{"text": "this is written like a traditional blood pressure measurement. an example is a pulmonary artery pressure 90 / 40. the mean pap is a function of the upper ( systolic ) and lower ( diastolic ) number. see also pulmonary artery pressure magnetic resonance imaging ( mri ) : an imaging technique that uses a strong magnetic field and low - energy radio waves to make pictures of the inside of the body. mri images usually have great detail, and can allow doctors to make some diagnoses much easier. in ph, mri is currently being used to capture better pictures of the heart, heart valves and the functioning of the heart than seen on an echocardiogram. sometimes used with radiopaque dye. read more about common tests in ph back to top of page - n - national heart, lung, and blood institute ( nhlbi ) : a government institute that is part of the national institutes of health. the nhlbi coordinates basic research, clinical investigations and trials, observational studies, and education projects related to the causes, prevention, diagnosis, and treatment of heart, blood vessel, lung and blood diseases as well as sleep disorders. pha interacts with the nhlbi through the agency \u2019 s public interest organizations group. learn more about the nhlbi national institutes of health ( nih ) : the national institutes of health, a part of the u. s. department of health and human services whose mission is \u201c to seek fundamental knowledge about the nature and behavior of living systems and the application of that knowledge to enhance health, lengthen life, and reduce the burdens of illness and disability. \u201d learn more about the nih nebulizer : a machine that can aerosolize medications so that they can be inhaled. nitric oxide ( no ) : a potent vasodilator in gas form. ( not the same thing as nitrous oxide, which is \u201c laughing gas \u201d used during dental procedures. ) it is delivered through a face mask or nasal cannula like oxygen. it has been approved by the fda for use in newborn babies with persistent pulmonary hypertension. it is being used experimentally for adults with pah. back to top of page - o - oximeter / pulse oximeter : a device to measure the concentration of oxygen in your blood by measuring the color in your skin ( usually finger or earlobe ). normal saturation is around 97 - 100 percent. in patients with lung disease, it is generally desirable to be above 90 percent \u201c saturated. \u201d some patients with congenital heart disease have", "subdomain_id": "subdomain_quantum_metrology", "similarity_score": 0.6119000796920608, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 11, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:09.263497"} {"text": "phineas parkhurst quimby whence is it - of matter or wisdom? errors & misery resulting from the misapplication of the wordnovember 1861 what is strength? this question sounds as though it might be easily answered, but on consideration, it is not so easy. words are so misused that it it impossible to get at the original meaning of the person who applied the word - or at the feeling ( or state of mind ) when the word was first introduced. if you choose to apply the word \" strength \" to machinery - then i have no fault to find with the definition. but if it means will, then it is wrongly applied - for will is independent of the thing you call strong. if you say, \" that is a strong lever \" - then it does not include the force that is applied to it. if the person who first used the word applied it to his wisdom as a powerful intellect - then it will only apply where there is some intellect - the quality of which is not taken into account. this confusion of meaning makes a great deal of trouble, for we put intelligence into everything that has resistance - instead of in the intelligence having the strength. as far as man is concerned the word \" strength \" has no meaning at all - unless you call it \" will. \" a man ' s legs are a combined lever - and if you mean that they have strength - you might as well say that a lever has strength ; for one is as much alive as the other - and neither, of itself, can do anything. the word \" strength \" does not convey the author ' s feelings when he made the expression. he either meant to apply it to wisdom - or to matter. if the author meant to give a name to the phenomenon called \" will \" - then it makes a vast difference in reasoning about strength. for instance, a person is \" weak, \" as it is called, in the back or limbs. now the medical faculty goes to work to rub on all kinds of strengthening medicines - just as though there were intelligence in the medicine, and it imparted strength to the weak part. the absurd idea is carried out all through our lives - and it deprives man of the true wisdom that might make him happy and intelligent. my theory gives the lie to all the above, for i have seen that the word \" strength \" is a mere word with no more meaning than to lead man astray - and the whole medical science is based on this word \" strength. \" this or", "subdomain_id": "subdomain_quantum_field_theory", "similarity_score": 0.6381419001792543, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:09.318820"} {"text": "atmospheric sciences & global change division dust achieves lofty aspirations disposition to form ice crystals is measured and modeled for a new - fangled framework this conceptual model illustrates the path pnnl researchers used to steer multiple data points into one flexible calculation, efficiently simulating how ice forms on dust particles and produces clouds. this universal calculation will help them describe how ice crystals are formed on other particles, such as atmospheric soot, organic, and biological particles. enlarge image results : instead of dust - bunnies under the sofa, this dust helps form ice crystals that are at the heart of clouds. researchers at pacific northwest national laboratory used dust \u2019 s loftier disposition to create a new way to calculate how all particles, not just dust, attract and form ice crystals in clouds. steering multiple data points into one flexible calculation, they efficiently simulated how ice forms on dust particles, a calculation that will help them nail down how ice latches on to atmospheric soot, organic, and biological particles as well. their research was published in the august issue of atmospheric chemistry and physics. why it matters : the u. s. and other parts of the world are suffering record drought this year. looking at the genesis of rain and snow, and how the earth warms and cools are crucial to daily life. tiny ice crystals in the clouds can be instigators of rain and snow. ice crystals can reflect and scatter sunlight away from the earth, cooling the surface. thus, ice crystals are tiny provocateurs for both precipitation and earth \u2019 s warming and cooling. scientists in this study are tracking down the very basics of how ice forms in the atmosphere, beginning with its attraction to dust \u2013 one of several ways that ice crystals form. their finding of a universal calculation for how this happens will enable them to model and predict other ways that ice crystals are formed. methods : previously, scientists had to rely on individual data points to represent the process of ice forming on dust particles. in this study, pnnl researchers developed a new way to translate multiple observation data points into one efficient parameterization framework used in cloud and climate models. parameterizations are calculations that allow scientists to represent field or laboratory observations in computer simulations. this framework not only works on dust particles shown in this study, it can be used with many different data sets. the framework takes into account a standard way to measure how efficiently ice forms on a substance and calculated the probability that a seed particle \u2014 in this case dust \u2014 will form an ice crystal. the higher the contact angle,", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6053621042103429, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:09.349866"} {"text": "the basic requirements for a synthetic motor are repetitive 360\u00b0 motion, the consumption of energy and unidirectional rotation. two efforts in this direction were published in 1999 in the same issue of nature. for the two reports below, it is unknown whether these molecules are capable of generating torque. it is expected that reports of more efforts in this field will increase, as understanding of chemistry and physics at the nanolevel improves. this rotation takes place in five steps. first, the amine group present on the triptycene moiety is converted to an isocyanate group by condensation with a phosgene molecule ( a ). thermal or spontaneous rotation around the central bond then brings the isocyanate group in proximity of the hydroxyl group located on the helicene moiety ( b ), thereby allowing these two groups to react with each other ( c ). this reaction irreversibly traps the system as a strained cyclic urethane that is higher in energy and thus energetically closer to the rotational energy barrier than the original state. further rotation of the triptycene moiety therefore requires only a relatively small amount of thermal activation in order to overcome this barrier, thereby releasing the strain ( d ). finally, cleavage of the urethane group restores the amine and alcohol functionalities of the molecule ( e ). the result of this sequence of events is a unidirectional 120\u00b0 rotation of the triptycene moiety with respect to the helicene moiety. additional forward or backward rotation of the triptycene rotor is inhibited by the helicene moiety, which serves a function similar to that of the pawl of a ratchet. the unidirectionality of the system is a result from both the asymmetric skew of the helicene moiety as well as the strain of the cyclic urethane which is formed in c. this strain can be only be lowered by the clockwise rotation of the triptycene rotor in d, as both counterclockwise rotation as well as the inverse process of d are energetically unfavorable. in this respect, the preference for the rotation direction is determined by both the positions of the functional groups and the shape of the helicene, and is thus built into the design of the molecule instead of dictated by external factors. the motor by kelly and co - workers is an elegant example of how chemical energy can be used to induce controlled, unidirectional rotational motion", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6002476572214862, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:09.635123"} {"text": "software developers are racing to patch a recently discovered vulnerability that allows attackers to recover the plaintext of authentication cookies and other encrypted data as they travel over the internet and other unsecured networks. the discovery is significant because in many cases it makes it possible for attackers to completely subvert the protection provided by the secure sockets layer and transport layer protocols. together, ssl, tls, and a close tls relative known as datagram transport layer security are the sole cryptographic means for websites to prove their authenticity and to encrypt data as it travels between end users and web servers. the so - called \" lucky thirteen \" attacks devised by computer scientists to exploit the weaknesses work against virtually all open - source tls implementations, and possibly implementations supported by apple and cisco systems as well. ( microsoft told the researchers it has determined its software isn ' t susceptible. ) the attacks are extremely complex, so for the time being, average end users are probably more susceptible to attacks that use phishing e - mails or rely on fraudulently issued digital certificates to defeat the web encryption protection. nonetheless, the success of the cryptographers ' exploits \u2014 including the full plaintext recovery of data protected by the widely used openssl implementation \u2014 has clearly gotten the attention of the developers who maintain those programs. already, the opera browser and polarssl have been patched to plug the hole, and developers for openssl, nss, and cyassl are expected to issue updates soon. \" the attacks can only be carried out by a determined attacker who is located close to the machine being attacked and who can generate sufficient sessions for the attacks, \" nadhem j. alfardan and kenneth g. paterson researchers wrote in a web post that accompanied their research. \" in this sense, the attacks do not pose a significant danger to ordinary users of tls in their current form. however, it is a truism that attacks only get better with time, and we cannot anticipate what improvements to our attacks, or entirely new attacks, may yet be discovered. \" a pdf of their paper is here. how it works lucky thirteen uses a technique known as a padding oracle that works against the main cryptographic engine in tls that performs encryption and ensures the integrity of data. it processes data into 16 - byte chunks using a routine known as mee, which runs data through a mac ( message authentication code ) algorithm, then encodes and encrypts it. the routine adds \" padding \" data to the cipher", "subdomain_id": "subdomain_quantum_cryptography", "similarity_score": 0.6036373549435473, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:10.298915"} {"text": "a treatise on electricity and magnetism / part i / chapter i | \u2190part i : electrostatics | | a treatise on electricity and magnetism by part i, chapter i : description of phenomena | chapter ii : elementary mathematical theory of electricity\u2192 | | scanned pages for this section can be found starting here. | description of phenomena. electrification by friction. 27. ] experiment i. let a piece of glass and a piece of resin, neither of which exhibits any electrical properties, be rubbed together and left with the rubbed surfaces in contact. they will still exhibit no electrical properties. let them be separated. they will now attract each other. if a second piece of glass be rubbed with a second piece of resin, and if the pieces be then separated and suspended in the neighbourhood of the former pieces of glass and resin, it may be observed \u2014 - that the two pieces of glass repel each other. - that each piece of glass attracts each piece of resin. - that the two pieces of resin repel each other. these phenomena of attraction and repulsion are called electrical phenomena, and the bodies which exhibit them are said to be electrified, or to be charged with electricity bodies may be electrified in many other ways, as well as by friction. the electrical properties of the two pieces of glass are similar to each other but opposite to those of the two pieces of resin, the glass attracts what the resin repels and repels what the resin attracts. if a body electrified in any manner whatever behaves as the glass does, that is, if it repels the glass and attracts the resin, the body is said to be vitreously electrified, and if it attracts the glass and repels the resin it is said to be resinously electrified. all electrified bodies are found to be either vitreously or resinously electrified. it is the established practice of men of science to call the vitreous electrification positive, and the resinous electrification negative. the exactly opposite properties of the two kinds of electrification justify us in indicating them by opposite signs, but the application of the positive sign to one rather than to the other kind must be considered as a matter of arbitrary convention, just as it is a matter of convention in mathematical diagrams to reckon positive distances towards the right hand. no force, either of attraction or of repulsion, can be observed between an electrified body and a body not electrified. when, in any case, bodies not previously electrified are observed to be acted on by an electrified body, it is because they have become electrified by induction", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6278520434937575, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.079501"} {"text": "of attraction or of repulsion, can be observed between an electrified body and a body not electrified. when, in any case, bodies not previously electrified are observed to be acted on by an electrified body, it is because they have become electrified by induction. electrification by induction 28. ] experiment ii. let a hollow vessel of metal be hung up by white silk threads, and let a similar thread be attached to the lid of the vessel so that the vessel may be opened or closed without touching it. let the pieces of glass and resin be similarly suspended and electrified as before. let the vessel be originally unelectrified, then if an electrified piece of glass is hung up within it by its thread without touching the vessel, and the lid closed, the outside of the vessel will be found to be vitreously electrified, and it may be shewn that the electrification outside of the vessel is exactly the same in whatever part of the interior space the glass is suspended. if the glass is now taken out of the vessel without touching it, the electrification of the glass will be the same as before it was put in, and that of the vessel will have disappeared. this electrification of the vessel, which depends on the glass being within it, and which vanishes when the glass is removed, is called electrification by induction. similar effects would be produced if the glass were suspended near the vessel on the outside, but in that case we should find an electrification vitreous in one part of the outside of the vessel and resinous in another, when the glass is inside the vessel the whole of the outside is vitreously and the whole of the inside resinously electrified. electrification by conduction. 29 ] experiment iii. let the metal vessel he electrified by induction, as in the last experiment, let a second metallic body be suspended by white silk threads near it, and let a metal wire, similarly suspended, he brought so as to touch simultaneously the electrified vessel and the second body. the second body will now be found to be vitreously electrified, and the vitreous electrification of the vessel will have diminished. the electrical condition has been transferred from the vessel to the second body by means of the wire. the wire is called a conductor of electricity, and the second body is said to be electrified by conduction. conductors and insulators. experiment iv. if a glass rod, a stick of resin or gutta - percha, or a white silk thread, had been used instead of the metal wire, no transfer of electricity would have taken", "subdomain_id": "subdomain_quantum_optics", "similarity_score": 0.6093533680969558, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 1, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.080613"} {"text": "conduction. conductors and insulators. experiment iv. if a glass rod, a stick of resin or gutta - percha, or a white silk thread, had been used instead of the metal wire, no transfer of electricity would have taken place. hence these latter substances are called non - conductors of electricity. non - conductors are used in electrical experiments to support electrified bodies without carrying off their electricity. they are then called insulators. the metals are good conductors ; air, glass, resins, gutta - percha, vulcanite, paraffin, & c. are good insulators ; but, as we shall see afterwards, all substances resist the passage of electricity, and all substances allow it to pass, though in exceedingly different degrees. this subject will be considered when we come to treat of the motion of electricity. for the present we shall consider only two classes of bodies, good conductors, and good insulators. in experiment ii an electrified body produced electrification in the metal vessel while separated from it by air, a non - conducting medium. such a medium, considered as transmitting these electrical effects without conduction, has been called by faraday a dielectric medium, and the action which takes place through it is called induction. in experiment iii the electrified vessel produced electrification in the second metallic body through the medium of the wire. let us suppose the wire removed, and the electrified piece of glass taken out of the vessel without touching it, and removed to a sufficient distance. the second body will still exhibit vitreous electrification, but the vessel, when the glass is removed, will have resinous electrification. if we now bring the wire into contact with both bodies, conduction will take place along the wire, and all electrification will disappear from both bodies, showing that the electrification of the two bodies was equal and opposite, 30. ] experiment v. in experiment ii it was shown that if a piece of glass, electrified by rubbing it with resin, is hung up in an insulated metal vessel, the electrification observed outside does not depend on the position of the glass. if we now introduce the piece of resin with which the glass was rubbled into the same vessel, without touching it or the vessel, it will be found that there is no electrification outside the vessel. from this we conclude that the electrification of the resin is exactly equal and opposite to that of the glass. by putting in any number of bodies, electrified in any way, it may be shown that the electrification of the outside of the vessel is", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.624713450036289, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 2, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.081615"} {"text": "is expressed by the equation known as the equation of continuity in hydrodynamics. it is not true of heat, for heat may be increased or diminished within a closed surface, without passing in or out through the surface, by the transformation of some other form of energy into heat, or of heat into some other form of energy. it is not true even of energy in general if we admit the immediate action of bodies at a distance. for a body outside the closed surface may make an exchange of energy with a body within the surface. but if all apparent action at a distance is the result of the action between the parts of an intervening medium, and if the nature of this action of the parts of the medium is clearly understood, then it is conceivable that in all cases of the increases or diminution of the energy within a closed surface we may be able to trace the passage of the energy in or out through that surface. there is, however, another reason which warrants us in asserting that electricity, as a physical quantity, synonymous with the total electrification of a body, is not, like heat, a form of energy. an electrified system has a certain amount or energy, and this energy can be calculated by multiplying the quantity of electricity in each of its parts by another physical quantity, called the potential, of that part, and taking half the sum of the products. the quantities ' electricity ' and ' potential, ' when multiplied together, produce the quantity ' energy. ' it is impossible, therefore, that electricity and energy should be quantities of the same category, for electricity is only one of the factors of energy, the other factor being ' potential. ' energy, which is the product of these factors, may also be considered as the product of several other pairs of factors, such as | a force | | \u00d7 | | a distance through which the force is to act. | | a mass | | \u00d7 | | gravitation acting through a certain height. | | a mass | | \u00d7 | | half the square of its velocity, | | a pressure | | \u00d7 | | a volume of fluid introduced into a vessal at that pressure | | a chemical affinity | | \u00d7 | | a chemical change, measured by the number of electro - chemical equivalents which enter into combination. | if we obtain distinct mechanical ideas of the nature of electric potential, we may combine these with the idea of energy to determine the physical category in which ' electricity ' is to be placed. 36. ] in most", "subdomain_id": "subdomain_quantum_thermodynamics", "similarity_score": 0.632639583464604, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 6, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.086428"} {"text": "equivalents which enter into combination. | if we obtain distinct mechanical ideas of the nature of electric potential, we may combine these with the idea of energy to determine the physical category in which ' electricity ' is to be placed. 36. ] in most theories on the subject, electricity is treated as a substance, but inasmuch as there are two kinds of electrification which, being combined, annul each other, and since we cannot conceive of two substances annulling each other, a distinction has been drawn between free electricity and combined electricity. theory of two fluidsin the theory called that of two fluids, all bodies, in their un - electrified state, are supposed to be charged with equal quantities of positive and negative electricity. these quantities are supposed to be so great that no process of electrification has ever yet deprived a body of all the electricity of either kind. the process of electrification, according to this theory, consists in taking a certain quantity p of positive electricity from the body a and communicating it to b, or in taking a quantity n of negative electricity from b and communicating it to a, or in some combination or these processes. the result will be that a will have p + n units of negative electricity over and above its remaining positive electricity, which is supposed to be in a state of combination with an equal quantity of negative electricity. this quantity p + n is called the free electricity, the rest is called the combined, latent, or fixed electricity. in most expositions of this theory the two electricities are called ' fluids, ' because they are capable of being transferred from one body to another, and are, within conducting bodies, extremely mobile. the other properties of fluids, such as their inertia, weight, and elasticity, are not attributed to them by those who have used the theory for merely mathematical purposes ; but the use of the word fluid has been apt to mislead the vulgar, including many men of science who are not natural philosophers, and who have seized on the word fluid as the only term in the statement of the theory which seemed intelligible to them. we shall see that the mathematical treatment of the subject has been greatly developed by writers who express themselves in terms of the ' two fluids ' theory. their results, however, have been deduced entirely from data which can be proved by experiment, and which must therefore be true, whether we adopt the theory of two fluids or not. the experimental verification of the mathematical results therefore is no evidence for or against the peculiar doctrines of this theory", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6488155052320939, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 7, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.087507"} {"text": "deduced entirely from data which can be proved by experiment, and which must therefore be true, whether we adopt the theory of two fluids or not. the experimental verification of the mathematical results therefore is no evidence for or against the peculiar doctrines of this theory. the introduction of two fluids permits us to consider the negative electrification of a and the positive electrification of b as the effect of any one of three different processes which would lead to the same result. we have already supposed it produced by the transfer of p units of positive electricity from a to b, together with the transfer of n units of negative electricity from b to a. but if ' p + n ' units of positive electricity had been transferred from a to b, or if p + n units of negative electricity had been transferred from b to a, the resulting ' free electricity ' on a and on b would have been the same as before, but the quantity of ' combined electricity ' in a would have been less in the second case and greater in the third than it was in the first. it would appear therefore, according to this theory, that it is possible to alter not only the amount of free electricity in a body, but the amount of combined electricity. but no phenomena have ever been observed in electrified bodies which can be traced to the varying amount of their combined electricities. hence either the combined electricities have no observable properties, or the amount of the combined electricities is incapable of variation. the first of these alternatives presents no difficulty to the mere mathematician, who attributes no properties to the fluids except those of attraction and repulsion, for in this point of view the two fluids simply annul one another, and their combination is a true mathematical zero. but to those who cannot use the word fluid without thinking of a substance it is difficult to conceive that the combination of the two fluids shall have no properties at all, so that the addition of more or less of the combination to a body shall not in any way affect it, either by increasing its mass or its weight, or altering some or its other properties. hence it has been supposed by some, that in every process of electrification exactly equal quantities of the two fluids are transferred in opposite directions, so that the total quantity of the two fluids in any body taken together remains always the same. by this new law they ' contrive to save appearances, ' forgetting that there would have been no need of the law except to reconcile the ' two fluids ' theory with facts, and to prevent it from predicting non - existent phenomena", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6319155659629558, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 8, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.088563"} {"text": "the same. by this new law they ' contrive to save appearances, ' forgetting that there would have been no need of the law except to reconcile the ' two fluids ' theory with facts, and to prevent it from predicting non - existent phenomena. theory of one fluid 37. ] in the theory of one fluid everything is the same as in the theory of two fluids except that, instead of supposing the two substances equal and opposite in all respects, one of them, generally the negative one, has been endowed with the properties and name of ordinary matter, while the other retains the name of the electric fluid. the particles of the fluid are supposed to repel one another according to the law of the inverse square of the distance, and to attract those of matter according to the same law. those of matter are supposed to repel each other and attract those of electricity. the attraction, however, between units of the different substances at unit of distance is supposed to be a very little greater than the repulsion between units of the same kind, so that a unit of matter combined with a unit of electricity will exert a force of attraction on a similar combination at a distance, this force, however, being exceedingly small compared with the force between two uncombined units. this residual force is supposed to account for the attraction of gravitation. unelectrified bodies are supposed to be charged with as many units of electricity as they contain of ordinary matter. when they contain more electricity or less, they are said to be positively or negatively electrified. this theory does not, like the two - field theory, explain too much. it requires us, however, to suppose the mass of the electric fluid so small that no attainable positive or negative electrification has yet perceptibly increased or diminished either the mass or the weight of a body, and it has not yet been able to assign sufficient reasons why the vitreous rather than the resinous electrification should be supposed due to an excess of electricity. one objection has sometimes been urged against this theory by men who ought to have reasoned better. it has been said that the doctrine that the particles of matter uncombined with electricity repel one another, is in direct antagonism with the well established fact that every particle of matter attracts every other particle throughout the universe. if the theory of one fluid were true we should have the heavenly bodies repelling one another. but it is manifest that the heavenly bodies, according to this theory, if they consisted of matter uncombined with electricity", "subdomain_id": "subdomain_quantum_field_theory", "similarity_score": 0.6157921907029156, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 9, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.089598"} {"text": "every other particle throughout the universe. if the theory of one fluid were true we should have the heavenly bodies repelling one another. but it is manifest that the heavenly bodies, according to this theory, if they consisted of matter uncombined with electricity, would be in the highest state of negative electrification, and would repel each other. we have no reason to believe that they are in such a highly electrified state, or could be maintained in that state. the earth and all the bodies whose attraction has been observed are rather in an unelectrified state, that is, they contain the normal charge of electricity, and the only action between them is the residual force lately mentioned. the artificial manner, however, in which this residual force is introduced is a much more valid objection to the theory. in the present treatise i propose, at different stages of the investigation, to test the different theories in the light of additional classes of phenomena. for my own part, i look for additional light on the nature of electricity from a study of what takes place in the space intervening between the electrified bodies. such is the essential character of the mode of investigation pursued by faraday in his experimental researches, and as we go on i intend to exhibit the results, as developed by faraday, w. thomson, & c., in a connected and mathematical form, so that we may perceive what phenomena are explained equally well by all the theories, and what phenomena indicate the peculiar difficulties of each theory. measurement of the force between electrified bodies. 38. ] forces may be measured in various ways. for instance, one of the bodies may be suspended from one arm of a delicate balance, and weights suspended from the other arm, till the body, when unelectrified, is in equilibrium. the other body may then be placed at a known distance beneath the first, so that the attraction or repulsion of the bodies when electrified may increase or diminish the apparent weight of the first. the weight which must be added to or taken from the other arm, when expressed in dynamical measure, will measure the force between the bodies. this arrangement was used by sir w. snow harris, and is that adopted in sir w. thomson ' s absolute electrometers. see art. 217. it is sometimes more convenient to use a torsion - balance in which a horizontal arm is suspended by a fine wire or fibre, so as to be capable of vibrating about the vertical wire as an axis, and the body is attached to one end of the arm and acted", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6174223376857085, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 10, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.091744"} {"text": "each of the positive units in will repel each of the positive units in with a certain force, say, making a total effect equal to. since the effect of negative electricity is exactly equal and opposite to that of positive electricity, each of the positive units in will attract each of the negative units in with the same force, making a total effect equal to. similarly the negative units in will attract the positive units in with a force, and will repel the negative units in with a force the total repulsion will therefore be ; and the total attraction will be the resultant repulsion will be now is the algebraical value of the charge on, and is that of the charge on, so that the resultant repulsion may be written, the quantities and being always understood to be taken with their proper signs. variation of the force with the distance. 40. ] having established the law of force at a fixed distance, we may measure the force between bodies charged in a constant manner and placed at different distances. it is found by direct measurement that the force, whether of attraction or repulsion, varies inversely as the square of the distance, so that if is the repulsion between two units at unit distance, the repulsion at distance will be and the general expression for the repulsion between units and units at distance will be definition of the electrostatic unit of electricity. 41. ] we have hitherto used a wholly arbitrary standard for our unit of electricity, namely, the electrification of a certain piece of glass as it happened to be electrified at the commencement of our experiments. we are now able to select a unit on a definite principle, and in order that this unit may belong to a general system we define it so that may be unity, or in other words \u2014 the electrostatic unit of electricity is that quantity of electricity which, when placed at unit of distance from an equal quantity, repels it with unit of force. this unit is called the electrostatic unit to distinguish it from the electromagnetic unit, to be afterwards defined. we may now write the general law of electrical action in the simple form dimensions of the electrostatic unit of quantity. 42. ] if is the concrete electrostatic unit of quantity itself, and, the numerical values of particular quantities ; if is the unit of length, and the numerical value of the distance ; and if is the unit of force, and the numerical value of the force, then the equation becomes. this unit is called the electrostatic unit of electricity. other units may be employed for practical purposes, and in", "subdomain_id": "subdomain_quantum_optics", "similarity_score": 0.6086967817112132, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 12, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.094457"} {"text": "and measurements ( which may be used as illustrations of the law ), but by a mathematical consideration of the phenomenon described as experiment vii, namely, that an electrified conductor, if made to touch the inside of a hollow closed conductor and then withdrawn without touching, is perfectly discharged, in whatever manner the outside of may be electrified. by means of delicate electroscopes it is easy to show that no electricity remains on after the operation, and by the mathematical theory given at art. 74, this can only be the case if the force varies inversely as the square of the distance, for if the law had been of any different form would have been electrified. the electric field. 44. ] the electric field is the portion of space in the neighbourhood of electrified bodies, considered with reference to electric phenomena. it may be occupied by air or other bodies, or it may be a so - called vacuum, from which we have withdrawn every substance which we can act upon with the means at our disposal. if an electrified body be placed at any part of the electric field it will be acted on by a force which will depend, in general, on the shape of the body and on its charge, if the body is so highly charged as to produce a sensible disturbance in the previous electrification of the other bodies. but if the body is very small and its charge also very small, the electrification of the other bodies will not be sensibly disturbed, and we may consider the body as indicating by its centre of gravity a certain point of the field. the force acting on the body will then be proportional to its charge, and will be reversed when the charge is reversed. let be the charge of the body, and the force acting on the body in a certain direction, then when is very small is proportional to, or where is a quantity depending on the other bodies in the field. if the charge could be made equal to unity without disturbing the electrification of other bodies we should have. we shall call the resultant electric force at the given point of the field. 45. ] if the small body carrying the small charge be moved from the given point to an indefinite distance from the electrified bodies, it will experience at each point of its course a force, where varies from point to point of the course. let the whole work done on the body by these electrical forces be, then is the potential at the point of the field from which the body started. if the charge could be made equal to unity without disturbing the electrification of other bodies, we might define the potential at any", "subdomain_id": "subdomain_quantum_field_theory", "similarity_score": 0.6225577003324185, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 14, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.096573"} {"text": "done on the body by these electrical forces be, then is the potential at the point of the field from which the body started. if the charge could be made equal to unity without disturbing the electrification of other bodies, we might define the potential at any point as the work done on a body charged with unit of electricity in moving from that point to an infinite distance. a body electrified positively tends to move from places of greater positive potential to places of smaller positive, or of negative potential, and a body negatively electrified tends to move in the opposite direction. in a conductor the electrification is distributed exactly as if it were free to move in the conductor according to the same law. if therefore two parts of a conductor have different potentials, positive electricity will move from the part having greater potential to the part having less potential as long as that difference continues. a conductor therefore cannot be in electrical equilibrium unless every point in it has the same potential. this potential is called the potential of the conductor. 46. ] if a surface described or supposed to be described in the electric field is such that the electric potential is the same at every point of the surface it is called an equipotential surface. an electrified point constrained to rest upon such a surface will have no tendency to move from one part of the surface to another, because the potential is the same at every point. an equipotential surface is therefore a surface of equilibrium or a level surface. the resultant force at any point of the surface is in the direction of the normal to the surface, and the magnitude of the force is such that the work done on an electrical unit in passing from the surface v to the surface v ' is v - v '. no two equipotential surfaces having different potentials can meet one another, because the same point cannot have more than one potential, but one equipotential surface may meet itself, and this takes place at all points and lines of equilibrium. the surface of a conductor in electrical equilibrium is necessarily an equipotential surface. if the electrification of the conductor is the whole surface, then the potential will diminish as we move away from the surface on every side, and the conductor will be surrounded by a series of surfaces of lower potential. but if ( owing to the action of external electrified bodies ) some regions of the conductor are electrified positively and others negatively, the complete equipotential surface will consist of the surface of the conductor itself together with a system of other surfaces, meeting the surface of the conductor in the lines which", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.620348963445636, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 15, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.097647"} {"text": "proportional to the superficial density of the electrification. hence the electricity on any small area of the surface will be acted on by a force tending from the conductor and proportional to the product of the resultant force and the density, that is, proportional to the square of the resultant force. this force which acts outwards as a tension on every part of the conductor will be called electric tension. it is measured like ordinary mechanical tension, by the force exerted on unit of area. the word tension has been used by electricians in several vague senses, and it has been attempted to adopt it in mathematical language as a synonym for potential ; but on examining the cases in which the word has been used, i think it will be more consistent with usage and with mechanical analogy to understand by tension a pulling force of so many pounds per square inch exerted on the surface of a conductor or elsewhere. we shall find that the conception of faraday, that this electric tension exists not only at the electrified surface but all along the lines of force, leads to a theory of electric action as a phenomenon of stress in a medium. 49. ] when two conductors at different potentials are connected by a thin conducting wire, the tendency of electricity to flow along the wire is measured by the difference of the potentials of the two bodies. the difference of potentials between two conductors or two points is therefore called the electromotive force between them. electromotive force may arise from other causes than difference of potential, but these causes are not considered in treating of statical electricity. we shall consider them when we come to chemical actions, motions of magnets, inequalities of temperature, & c. capacity of a conductor. 50. ] if one conductor is insulated while all the surrounding conductors are kept at the zero potential by being put in communication with the earth, and if the conductor, when charged with a quantity of electricity, has a potential, the ratio of to is called the capacity of the conductor. if the conductor is completely enclosed within a conducting vessel without touching it, then the charge on the inner conductor will be equal and opposite to the charge on the inner surface of the outer conductor, and will be equal to the capacity of the inner conductor multiplied by the difference of the potentials of the two conductors. a system consisting of two conductors whose opposed surfaces are separated from each other by a thin stratum of an insulating medium is called an electric accumulator. its capacity is directly proportional to the area of the opposed surfaces and inversely proportional to", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6031256035448495, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 17, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.099637"} {"text": "a system consisting of two conductors whose opposed surfaces are separated from each other by a thin stratum of an insulating medium is called an electric accumulator. its capacity is directly proportional to the area of the opposed surfaces and inversely proportional to the thickness of the stratum between them. a leyden jar is an accumulator in which glass is the insulating medium. accumulators are sometimes called condensers, but i prefer to restrict the term condenser to an instrument which is used not to hold electricity but to increase its superficial density. resistance to the passage of electricity through a body. 51. ] when a charge of electricity is communicated to any part of a mass of metal the electricity is rapidly transferred from places of high to places of low potential till the potential of the whole mass becomes the same. in the case of pieces of metal used in ordinary experiments this process is completed in a time too short to be observed, but in the case of very long and thin wires, such as those used in telegraphs, the potential does not become uniform till after a sensible time, on account of the resistance of the wire to the passage of electricity through it. the resistance to the passage of electricity is exceedingly different in different substances, as may be seen from the tables at arts. 362, 366, and 369, which will be explained in treating of electric currents. all the metals are good conductors, though the resistance of lead is 12 times that of copper or silver, that of iron 6 times, and that of mercury 60 times that of copper. the resistance of all metals increases as their temperature rises. selenium in its crystalline state may also be regarded as a conductor, though its resistance is 3. 7\u00d71012 times that of a piece of copper of the same dimensions. its resistance increases as the temperature rises. selenium in the amorphous form is a good insulator, like sulphur. many liquids conduct electricity by electrolysis. this mode of conduction will be considered in part ii. for the present, we may regard all liquids containing water and all damp bodies as conductors, far inferior to the metals, but incapable of insulating a charge of electricity for a sufficient time to be observed. on the other hand, the gases at the atmospheric pressure, whether dry or moist, are insulators so nearly perfect when the electric tension is small that we have as yet obtained no evidence of electricity passing through them by ordinary conduction. the gradual loss of charge", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6420525927130223, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 18, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.100585"} {"text": "hand, the gases at the atmospheric pressure, whether dry or moist, are insulators so nearly perfect when the electric tension is small that we have as yet obtained no evidence of electricity passing through them by ordinary conduction. the gradual loss of charge by electrified bodies may in every case be traced to imperfect insulation in the supports, the electricity either passing through the substance of the support or creeping over its surface. hence, when two charged bodies are hung up near each other, they will preserve their charges longer if they are electrified in opposite ways, than if they are electrified in the same way. for though the electromotive force tending to make the electricity pass through the air between them is much greater when they are oppositely electrified, no perceptible loss occurs in this way. the actual loss takes place through the supports, and the electromotive force through the supports is greatest when the bodies are electrified in the same way. the result appears anomalous only when we expect the loss to occur by the passage of electricity through the air between the bodies. certain kinds of glass when cold are marvelously perfect insulators, and sir w. thomson has preserved charges of electricity for years in bulbs hermetically sealed. the same glass, however, becomes a conductor at a temperature below that of boiling water. gutta - percha, caoutchoue, vulcanite, paraffin, and resins are good insulators, the resistance of gutta - percha at 75\u00b0f. being about 6\u00d71019 times that of copper. ice, crystals, and solidified electrolytes, are also insulators. certain liquids, such as naphtha, turpentine, and some oils, are insulators, but inferior to most of the solid insulators. the resistance of most substances, except the metals, and selenium and carbon, seems to diminish as the temperature rises. specific inductive capacity. 52. ] all bodies whose insulating power is such that when they are placed between two conductors at different potentials the electromotive force acting on them does not immediately distribute their electricity so as to reduce the potential to a constant value, are called by faraday dielectrics. faraday discovered that the capacity of an accumulator depends on the nature of the insulating medium between the two conductors, as well as on the dimensions and relative position of the conductors themselves. by substituting other insulating media for air as the dielectric of the", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6256771308277427, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 19, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.101703"} {"text": "a discharge, will be too great. the accumulator if charged and left insulated appears to lose its charge by conduction, but it is found that the proportionate rate of loss is much greater at first than it is afterwards, so that the measure of conductivity, if deduced from what takes place at first, would be too great. thus, when the insulation of a submarine cable is tested, the insulation appears to improve as the electrification continues. thermal phenomena of a kind at first sight analogous take place in the case of the conduction of heat when the opposite sides of a body are kept at different temperatures. in the case of heat we know that they depend on the heat taken in and given out by the body itself. hence, in the case of the electrical phenomena, it has been supposed that electricity is absorbed and emitted by the parts of the body. we shall see, however, in art. 329, that the phenomena can be explained without the hypothesis of absorption of electricity, by supposing the dielectric in some degree heterogeneous. that the phenomenon called electric absorption is not an actual absorption of electricity by the substance may be shewn by charging the substance in any manner with electricity while it is surrounded by a closed metallic insulated vessel. if, when the substance is charged and insulated, the vessel be instantaneously discharged and then left insulated, no charge is ever communicated to the vessel by the gradual dissipation of the electrification of the charged substance within it. 54. ] this fact is expressed by the statement of faraday that it is impossible to charge matter with an absolute and independent charge of one kind of electricity. in fact it appears from the result of every experiment which has been tried that in whatever way electrical actions may take place among a system of bodies surrounded by a metallic vessel, the charge on the outside of that vessel is not altered. now if any portion of electricity could be forced into a body so as to be absorbed in it, or to become latent, or in any way to exist in it, without being connected with an equal portion of the opposite electricity by lines of induction, or if, after having being absorbed, it could gradually emerge and return to its ordinary mode of action, we should find some change of electrification in the surrounding vessel. as this is never found to be the case, faraday concluded that it is impossible to communicate an absolute charge to matter, and that no portion of matter can by any change of state evolve or render latent one", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6146058617808414, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 21, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.103718"} {"text": "its surface. let its temperature be now raised, the crystal remaining insulated. one end will be found positively and the other end negatively electrified. let the surface be deprived of this apparent electrification by means of a flame or other wise, then if the crystal be made still hotter, electrification of the same kind as before will appear, but if the crystal be cooled the end which was positive when the crystal was heated will become negative. these electrifications are observed at the extremities of the crystallographic axis. some crystals are terminated by a six - sided pyramid at one end and by a three - sided pyramid at the other. in these the end having the six - sided pyramid becomes positive when the crystal is heated. sir w. thomson supposes every portion of these and other hemihedral crystals to have a definite electric polarity, the intensity of which depends on the temperature. when the surface is passed through a flame, every part of the surface becomes electrified to such an extent as to exactly neutralize, for all external points, the effect of the internal polarity. the crystal then has no external electrical action, nor any tendency to change its mode of electrification. but if it be heated or cooled the interior polarization of each particle of the crystal is altered, and can no longer be balanced by the superficial electrification, so that there is a resultant external action. plan of this treatise. 59. ] in the following treatise i propose first to explain the ordinary theory of electrical action, which considers it as depending only on the electrified bodies and on their relative position, without taking account of any phenomena which may take place in the surrounding media. in this way we shall establish the law of the inverse square, the theory of the potential, and the equations of laplace and poisson. we shall next consider the charges and potentials of a system of electrified conductors as connected by a system of equations, the coefficients of which may be supposed to be determined by experiment in those cases in which our present mathematical methods are not applicable, and from these we shall determine the mechanical forces acting between the different electrified bodies. we shall then investigate certain general theorems by which green, gauss, and thomson have indicated the conditions of solution of problems in the distribution of electricity. one result of these theorems is, that if poisson ' s equation is satisfied by any function, and if at the surface of every conductor the function has the value of the potential of that conductor, then the function expresses the actual potential of the system at every point.", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6421364107488995, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 27, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.111387"} {"text": ", we shall find it equal to the energy due to the electrification of the conductors on the hypothesis of direct action at a distance. hence the two hypotheses are mathematically equivalent. if we now proceed to investigate the mechanical state of the medium on the hypothesis that the mechanical action observed between electrified bodies is exerted through and by means of the medium, as in the familiar instances of the action of one body on another by means of the tension of a rope or the pressure of a rod, we find that the medium must be in a state of mechanical stress. the nature of this stress is, as faraday pointed out, a tension along the lines of force combined with an equal pressure in all directions at right angles to these lines. the magnitude of these stresses is proportional to the energy of the electrification, or, in other words, to the square of the resultant electromotive force multiplied by the specific inductive capacity of the medium. this distribution of stress is the only one consistent with the observed mechanical action on the electrified bodies, and also with the observed equilibrium of the fluid dielectric which surrounds them. i have therefore thought it a warrantable step in scientific procedure to assume the actual existence of this state of stress, and to follow the assumption into its consequences. finding the phrase electric tension used in several vague senses, i have attempted to confine it to what i conceive to have been in the mind of some of those who have used it, namely, the state of stress in the dielectric medium which causes motion of the electrified bodies, and leads, when continually augmented, to disruptive discharge. electric tension, in this sense, is a tension of exactly the same kind, and measured in the same way, as the tension of a rope, and the dielectric medium, which can support a certain tension and no more, may be said to have a certain strength in exactly the same sense as the rope is said to have a certain strength. thus, for example, thomson has found that air at the ordinary pressure and temperature can support an electric tension of 9600 grains weight per square foot before a spark passes. 60. ] from the hypothesis that electric action is not a direct action between bodies at a distance, but is exerted by means of the medium between the bodies, we have deduced that this medium must be in a state of stress. we have also ascertained the character of the stress, and compared it with the stresses which may occur in solid bodies. along the lines of force", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6154432292545752, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 29, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.113733"} {"text": "medium between the bodies, we have deduced that this medium must be in a state of stress. we have also ascertained the character of the stress, and compared it with the stresses which may occur in solid bodies. along the lines of force there is tension, and perpendicular to them there is pressure, the numerical magnitude of these forces being equal, and each proportional to the square of the resultant force at the point. having established these results, we are prepared to take another step, and to form an idea of the nature of the electric polarization of the dielectric medium. an elementary portion of a body may be said to be polarized when it acquires equal and opposite properties on two opposite sides. the idea of internal polarity may be studied to the greatest advantage as exemplified in permanent magnets, and it will be explained at greater length when we come to treat of magnetism. the electric polarization of an elementary portion of a dielectric is a forced state into which the medium is thrown by the action of electromotive force, and which disappears when that force is removed. we may conceive it to consist in what we may call an electrical displacement, produced by the electromotive force. when the electromotive force acts on a conducting medium it produces a current through it, but if the medium is a non - conductor or dielectric, the current cannot flow through the medium, but the electricity is displaced within the medium in the direction of the electromotive force, the extent of this displacement depending on the magnitude of the electromotive force, so that if the electromotive force increases or diminishes the electric displacement increases and diminishes in the same ratio. the amount of the displacement is measured by the quantity of electricity which crosses unit of area, while the displacement increases from zero to its actual amount. this, therefore, is the measure of the electric polarization. the analogy between the action of electromotive force in producing electric displacement and of ordinary mechanical force in producing the displacement of an elastic body is so obvious that i have ventured to call the ratio of the electromotive force to the corresponding electric displacement the coefficient of electric elasticity of the medium. this coefficient is different in different media, and varies inversely as the specific inductive capacity of each medium. the variations of electric displacement evidently constitute electric currents. these currents, however, can only exist during the variation of the displacement, and therefore, since the displacement cannot exceed a certain value without causing disrupt", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6382368695966418, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 30, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.114898"} {"text": "as the specific inductive capacity of each medium. the variations of electric displacement evidently constitute electric currents. these currents, however, can only exist during the variation of the displacement, and therefore, since the displacement cannot exceed a certain value without causing disruptive discharge, they cannot be continued indefinitely in the same direction, like the currents through conductors. in tourmaline, and other pyro - electric crystals, it is probable that a state of electric polarization exists, which depends upon temperature, and does not require an external electromotive force to produce it if the interior of a body were in a state of permanent electric polarization, the outside would gradually become charged in such a manner as to neutralize the action of the internal electrification for all points outside the body. this external superficial charge could not be detected by any of the ordinary tests, and could not be removed by any of the ordinary methods for dis charging superficial electrification. the internal polarization of the substance would therefore never be discovered unless by some means, such as change of temperature, the amount of the internal polarization could be increased or diminished. the external electrification would then be no longer capable of neutralizing the external effect of the internal polarization, and an apparent electrification would be observed, as in the case of tourmaline. if a charge is uniformly distributed over the surface of a sphere, the resultant force at any point of the medium surrounding the sphere is numerically equal to the charge e divided by the square of the distance from the centre of the sphere. this resultant force, according to our theory, is accompanied by a displacement of electricity in a direction outwards from the sphere. if we now draw a concentric spherical surface of radius, the whole displacement,, through this surface will be proportional to the resultant force multiplied by the area of the spherical surface. but the resultant force is directly as the charge e and inversely as the square of the radius, while the area of the surface is directly as the square of the radius. hence the whole displacement,, is proportional to the charge, and is independent of the radius. to determine the ratio between the charge, and the quantity of electricity,, displaced outwards through the spherical surface, let us consider the work done upon the medium in the region between two concentric spherical surfaces, while the displacement is increased from to. if and denote the potentials at the inner and the outer of these surfaces respectively, the electromotive force by which the additional displacement is produced is, so that the work spent in", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.620408584571772, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 31, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.116156"} {"text": "circuit, such that at every section of the circuit the same quantity of electricity crosses in the same time, and this is the case, not only in the voltaic circuit where it has always been recognised, but in those cases in which electricity has been generally supposed to be accumulated in certain places. 61. ] we are thus led to a very remarkable consequence of the theory which we are examining, namely, that the motions of electricity are like those of an incompressible fluid, so that the total quantity within an imaginary fixed closed surface remains always the same. this result appears at first sight in direct contradiction to the fact that we can charge a conductor and then introduce it into the closed space, and so alter the quantity of electricity within that space. but we must remember that the ordinary theory takes no account of the electric displacement in the substance of dielectrics which we have been investigating, but confines its attention to the electrification at the bounding surfaces of the conductors and dielectrics. in the case of the charged conductor let us suppose the charge to be positive, then if the surrounding dielectric extends on all sides beyond the closed surface there will be electric polarization, accompanied with displacement from within outwards all over the closed surface, and the surface - integral of the displacement taken over the surface will be equal to the charge on the conductor within. thus when the charged conductor is introduced into the closed space there is immediately a displacement of a quantity of electricity equal to the charge through the surface from within out wards, and the whole quantity within the surface remains the same. the theory of electric polarization will be discussed at greater length in chapter v, and a mechanical illustration of it will be given in art. 334, but its importance cannot be fully understood till we arrive at the study of electromagnetic phenomena. 62. ] the peculiar features of the theory as we have now developed them are : - that the energy of electrification resides in the dielectric medium, whether that medium be solid, liquid, or gaseous, dense or rare, or even deprived of ordinary gross matter, provided it be still capable of transmitting electrical action. that the energy in any part of the medium is stored up in the form of a state of constraint called electric polarization, the amount of which depends on the resultant electromotive force at the place. that electromotive force acting on a dielectric produces what we have called electric displacement, the relation between the force and the displacement being in the most general case of a kind to be afterwards investigated", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6315577732233832, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 33, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.119372"} {"text": "is set up, and the resistance depends, not on the total quantity of electricity displaced from its position of equilibrium, but on the quantity which crosses a section of the conductor in a given time. that in every case the motion of electricity is subject to the same condition as that of an incompressible fluid, namely, that at every instant as much must flow out of any given closed space as flows into it. it follows from this that every electric current must form a closed circuit. the importance of this result will be seen when we investigate the laws of electro - magnetism. since, as we have seen, the theory of direct action at a distance is mathematically identical with that of action by means of a medium, the actual phenomena may be explained by the one theory as well as by the other, provided suitable hypotheses be introduced when any difficulty occurs. thus, mossotti has deduced the mathematical theory of dielectrics from the ordinary theory of attraction by merely giving an electric instead of a magnetic interpretation to the symbols in the investigation by which poisson has deduced the theory of magnetic induction from the theory of magnetic fluids. he assumes the existence within the dielectric of small conducting elements, capable of having their opposite surfaces oppositely electrified by induction,, but not capable of losing or gaining electricity on the whole, owing to their being insulated from each other by a non - conducting medium. this theory of dielectrics is consistent with the laws of electricity, and may be actually true. if it is true, the specific inductive capacity of a dielectric may be greater, but cannot be less, than that of air or vacuum. no instance has yet been found of a dielectric having an inductive capacity less than that of air, but if such should be discovered, mossotti ' s theory must be abandoned, although his formulae would all remain exact, and would only require us to alter the sign of a coefficient. in the theory which i propose to develope, the mathematical methods are founded upon the smallest possible amount of hypothesis, and thus equations of the same form are found applicable to phenomena which are certainly of quite different natures, as, for instance, electric induction through dielectrics ; conduction through conductors, and magnetic induction. in all these cases the relation between the force and the effect produced is expressed by a set of equations of the same kind, so that when a problem in one of these subjects is solved, the problem and its solution may be", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6281455408144387, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 35, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.121952"} {"text": "in our last article we discussed how both the celsius and fahrenheit temperature scales aligned perfectly with the specific structural design of the future holy temple as laid out by ezekiel thousands of years ago, and moreover how the kelvin scale and the surface temperature of the planets aligned with the dates given by the tzaddikim for the final redemption. given that, and returning the the freezing point of water, 32 degrees fahrenheit, we see that the major structural dimensions of the future holy temple centers redundantly and concentrically on the 32 paths of wisdom that comprise the tree - of - life. as we lay out this structure for you in a 2 - dimensional grid, please note that the temple, like the tree - of - life, is multi - dimensional and should always be viewed that way, staring with the fact that 32 is 25, and that 32 represents the 32 edges ( paths ) of what is called in mathematics a 4 - dimensional hypercube. though our modern physicists, by and large, agree with the ancient kabbalists that the greater universe is constructed in 10 dimensions, we cannot even fathom, except mathematically, how a 4 - d cube, or indeed any object would actually look. nevertheless, in the same way that a 3 - d cube casts a 2 - d shadow on our desk, a 4 - d hypercube does the same in our 3 - d world. it \u2019 s by these shadows, much like plato \u2019 s cave, that we can glimpse and maybe grasp that upper dimension. the following illustrations are just such shadows of 4 - d hypercubes on our world, and the reason we need to perceive them before getting back to the temperature scales will be clear in a moment, but keep in mind that it \u2019 s only because of light that we have shadows and thus perception in the first place. one of the shapes that a 3 - d cube casts on a flat 2 - d page is a square, another is a hexagon, and likewise one of the shadows cast by our 4 - d hypercube on our 3 - d world is a cube itself ( if you follow the outlines in the blue image ). others, include the tesseract, as in the image above ( a cube within a cube ), and also the double stacked cubes, which once turned on its axis, forms the exact tree - of - life depiction kabbalists have been elaborating on for thousands of years. since we have a difficult time imagining hyper", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6009696590337048, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.377936"} {"text": "1 ) tiny beginnings & the grand unification in the beginning, the universe was smaller and hotter than a mustard seed. it was even smaller than that. smaller than tiny, more miniature than microscopic, and hotter than hot. it was smaller, denser, and had more potential energy than anything that exists today. within this invisible seed, the forces of nature were unified. they travelled bundled together in high energy packages that could be called quofs ( from the quanta of the unified field ), if anyone wanted to give them a name. however, they were only joined in this way due to the extremely extreme and tight conditions they found themselves in. as things began to open up, one by one the forces of nature separated within the primordial little nut. the first to loosen off was the force that holds all the big things together. it even sounds big. its name is gravity, and it shapes our universe on a galactic scale. despite the fact that it is absolutely everywhere, no - one fully understands how it works. it is a mysterious, omnipresent phenomenon. some think gravity is substantially different from the other forces, that it was always a separate entity from the beginning, and its effect can travel and disappear into other universes. whether it was part of the grand unification or not, at some point there were three forces bundled tightly together, which we shall call the strong unification. but these three didn \u2019 t much like being squeezed together either, and so a powerful member broke off from the trinity \u2013 the strong force. the strong force is called the strong force because it is strong. it works invisibly on the tiniest of scales, tightly binding together every object you can see around you. without it, matter would simply fall apart into a gloop of subatomic bits. the strong force \u2019 s separation from the rest was no casual affair. whilst going its own way, it spilt unprecedented quantities of energy in all directions and set off the most important event of the ever - so - young universe. in the blink of an eye, as quick as a bursting balloon seen in reverse, the universe inflated.", "subdomain_id": "subdomain_quantum_field_theory", "similarity_score": 0.6036896294930507, "token_count": 433, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.835168"} {"text": "( phys. org ) - - a voltage signal preceding failure of bridges and other structures made of powder has been documented by three researchers in the department of biomedical engineering at rutgers university. their findings, published on monday in proceedings of the national academy of sciences, are an important step forward. the authors note that it has been known for over a century that electrical signals are produced by material failure, for example during crack formation of crystals and glasses, or stick - slip motion of liquid mercury on glass. they say that slip events in cohesive powders also produce electrical signals, and that these signals can appear significantly in advance of slip events. key structural materialsceramics in turbines, chalk in cliffs, and concrete in bridgesare made from powders ; a voltage spike might precede cracking in these structures. the authors of the paper, electrostatic precursors to granular slip events, are troy shinbrot, nam h. kim, and nirmal thyagu, and they discuss their results from lab tests on powders. they documented a voltage signal. they studied how clumps of fine particles emit electrical voltages just before they crack. pulling powders apart seems to produce a voltage. shinbrot and his study team studied scoops of finely ground tylenol in a slowly - spinning cylinder. powder stuck to the sides, built up, and after reaching a certain height, cracked and tumbled down to the bottom. the mini avalanches \" created voltages higher than 100 volts. they discovered that the voltage spike sometimes preceded the avalanche by as much as five seconds. outside of rutgers, a doctoral candidate familiar with the electrification of granular systems noted that five seconds might not be meaningful to save people from an earthquake area but would be beneficial in a smart - grid setting in turning off technologies that might cause explosions or fires during a quake. the researchers at rutgers performed several experiments before reaching their conclusions ; they used different containers and different powders. bleached and unbleached flour, plaster and mortar were tried and the team found the same results. similar voltage signals are produced by crack - like defects in several powdered materials. failure of these materials, in turn, may be preceded by telltale electrical signals. they speculate that similar voltage changes could be warning signs of internal defects or of impending catastrophic failures in objects made of consolidated powders. the authors acknowledge that electrical disturbances have been reported in the past to precede major earthquakes and rockbursts, but many of these reports have been anecdot", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6023175866900599, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.897887"} {"text": "signs of internal defects or of impending catastrophic failures in objects made of consolidated powders. the authors acknowledge that electrical disturbances have been reported in the past to precede major earthquakes and rockbursts, but many of these reports have been anecdotal. at the same time, a growing body of field measurements will help other research efforts to more fully understand these events. we anticipate that the ability to generate correlated electrical signals and slip events in a controlled setting will enable future research to unveil the mechanisms leading to the curious effects. prof. shinbrot says a better understanding of the particles ' electrical interactions may enable technologies that predict breakages before they cause catastrophic damage. explore further : wearable electronics - the next fashion fad? more information : electrostatic precursors to granular slip events, pnas, published online before print june 11, 2012, doi : 10. 1073 / pnas. 1121596109 it has been known for over a century that electrical signals are produced by material failure, for example during crack formation of crystals and glasses, or stick - slip motion of liquid mercury on glass. we describe here new experiments revealing that slip events in cohesive powders also produce electrical signals, and remarkably these signals can appear significantly in advance of slip events. we have confirmed this effect in two different experimental systems and using two common powdered materials, and in a third experiment we have demonstrated that similar voltage signals are produced by crack - like defects in several powdered materials.", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6520129302097522, "token_count": 305, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 1, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:11.898468"} {"text": "how can i decrypt a message that was encrypted with a one - time pad? would i need to get that pad, and then reverse the process? i ' m confused here. one - time pad is unbreakable, assuming the pad is perfectly random, kept secret, used only once, and no plaintext is known. this is due to the properties of the exclusive - or ( xor ) operation. here ' s its truth table : note that it introduces no bit - skew - the number of 0s and 1s in the inputs are equal to the number of 0s and 1s in the output, i. e. two of each. furthermore, if you know only one element from a row, you cannot predict the values of the other two, since they are equally probable. for example, let ' s say we know that x is 0. there ' s an equal probability that a = 0 and b = 0, or a = 1 and b = 1. now let ' s say we know that x is 1. there ' s an equal probability that a = 0 and b = 1, or a = 1 and b = 0. it ' s impossible to predict. so, if you only know one element, you cannot possibly determine any information about a or b. the next interesting property is that it is reversible, i. e. so, if we take any value and xor it with itself, the result is cancelled out and it always results in 0. this means that, if we xor a value a with a value b, then later xor that result with either a or b, we get b or a respectively. the operation is reversible. this lends well to cryptography, because : as such, the following is perfectly secure : but only if message is the same length as key, key is perfectly random, key is only used once, and only one element is known to an attacker. if they know the ciphertext, but not the key or message, it ' s useless to them. they cannot possibly break it. in order to decrypt the message, you must know the entire key and the ciphertext. keep in mind that the key must be completely random, i. e. every bit must have an equal probability of being 1 or 0, and be completely independent of all other bits in the key. this actually turns out to be rather impractical, for a few reasons : the weak link here is your", "subdomain_id": "subdomain_quantum_cryptography", "similarity_score": 0.608190348249951, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:12.005471"} {"text": ". e. every bit must have an equal probability of being 1 or 0, and be completely independent of all other bits in the key. this actually turns out to be rather impractical, for a few reasons : the weak link here is your random number generator. the security of the one time pad is entirely limited by the security of your generator. since a perfect generator is almost impossible, a perfect one - time pad is almost impossible too. the final problem is that the key can only be used once. if you use it for two different messages, and the attacker knows both ciphertexts, he can xor them together to get the xor of the two plaintexts. this leaks all sorts of information ( e. g. which bits are equal ) and completely breaks the cipher. so, in conclusion, in a perfect one - time pad you need to know the ciphertext and key in order to decrypt it, but perfect one - time pads are almost impossible. one - time pads are extremely hard to break, in fact they are still used in some situations as if they are done correctly then they are essentially unbreakable. in a one - time pad system every character is changed by a stream of random data which is shared by both sides, without a copy of the pad you will not be able to break the code. one of the few weaknesses in the system is the random data source. in wwii british one - time pads were being broken and they traced it to a worker whose job it was to pull random numbered balls out of a drum. the way it was supposed to work was that the worker would spin the drum, pull out a ball at random without looking at it, spin again, pick again, etc, etc. the worker started taking shortcuts by pulling out more than one ball after each spin and looking at the numbers, picking out favorites. it introduced patterns which enabled the opposition to break the pads, and lives were lost as a result. the same is true today with pseudo - random number sources. encryption protocols that should take millennia to break will really only last for years or decades without a true random data source. assuming the encryption was competently done, the only way to decrypt is to get the pad. while one - time - pad encryption is provably impossible to break, note that it is also extraordinarily rare. part of the definition of otp is that the pad must contain truly random data, and truly random data can be hard to come by for", "subdomain_id": "subdomain_quantum_cryptography", "similarity_score": 0.611890582049937, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 1, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:12.006928"} {"text": "| biomimetic dye molecules for solar cells | pressing energy problems provide opportunities for solid - state physicists and chemists to solve a major challenge : solar cell adoption. though solar cells can use energy directly from the sun to produce electricity that can be converted efficiently into other kinds of energy, they are currently too costly to compete with traditional ( polluting ) energy sources. the most cost - effective solar cells are not high - end, high - efficiency single - crystal devices, but rather low - end cells based on organic molecules or conducting polymers. vital information for making organic solar cells more competitive for widespread implementation was obtained using near - edge x - ray absorption fine structure ( nexafs ) spectroscopy performed at als beamline 8. 0. 1. the relevant energy levels of biomimetic dye molecules were mapped out systematically by determining their unoccupied molecular orbitals and their orientation. organic molecules in dye - sensitized solar cells exhibit great potential to increase the efficiency and reduce the cost of photovoltaic power generation by allowing a wide variety of chemical modifications and combinations with inorganic nanocrystals. researchers investigated the x - ray absorption spectra of two classes of candidate dye molecules for dye - sensitized solar cells : phthalocyanines and porphyrins. these cloverleaf shaped molecules have a metal atom at the center, surrounded by a ring of nitrogen atoms ( in porphyrins, two rings in phthalocyanines ). in each, the metal atom can be exchanged for other atoms among the transition metals. but, how does this substitution affect the energy levels of the molecule? can these molecules be tailored to optimize their performance in solar cells? the highest energy efficiency is currently obtained with dyes based on ruthenium, a rare and expensive metal. in nature, the chemically similar but much more abundant element iron facilitates electron transfer, for example in hemoglobin and cytochrome c. the active center of these dyes \u2014 the heme \u2014 is similar to that of porphyrin molecules, but it contains additional atoms that form a three - dimensional cage around the central iron atom. it would be advantageous to understand such biomolecules, what makes them so efficient, and how to mimic them with smaller, more robust molecules for use in organic solar cells. in an organic solar cell, sunlight is absorbed by an optical transition between a molecule ' s highest occupied and lowest unoccupied molecular orbitals ( homo and lumo ). in the molecules", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6453123467475614, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:12.330174"} {"text": ", more robust molecules for use in organic solar cells. in an organic solar cell, sunlight is absorbed by an optical transition between a molecule ' s highest occupied and lowest unoccupied molecular orbitals ( homo and lumo ). in the molecules discussed here, the nitrogen cage and the central transition metal atom form the homo and lumo, whose close proximity and significant overlap facilitate electron transfer, which can be controlled by adjusting the orbital energies. the absorption of sunlight produces electrons and holes, which are ultimately responsible for producing electrical power at the solar cells ' electrodes. biomolecules are particularly good at separating electron \u2013 hole pairs produced by sunlight in a dye molecule and pulling them towards their destination with minimal energy loss, enabling optimal use of solar energy. x - ray absorption spectroscopy provides much more information than just that about energy levels : it monitors oxidation states, and when coupled with polarized synchrotron radiation, it reveals the orientation of the molecular orbitals. the multiplet structure of the metal spectra reveals the oxidation state of the metal atom in a dye molecule, which is crucial for electron transfer. in the course of this work, researchers found that iron and manganese ( two important transition metals in biomolecules ) easily change between + 2 and + 3 during the preparation of thin films such as those used in solar cells. this requires close monitoring to obtain reproducible solar cells. the polarization dependence of the spectra reveals the orientation of the molecules, which also varies depending on film preparation. this is critical for optimizing electron transport from dye molecules to electrodes. molecular conductivity is commonly poor, but can be mitigated by orienting the molecular orbitals of neighboring molecules such that they overlap optimally. research conducted by p. l. cook, f. j. himpsel and x. liu ( university of wisconsin madison ) ; and w. yang ( berkeley lab ). research funding : u. s. department of energy and the national science foundation. operation of the als and ssrl are supported by the u. s. department of energy, office of basic energy sciences. publication about this research : p. l. cook, x. liu, w. yang, and f. j. himpsel, \" x - ray absorption spectroscopy of biomimetic dye molecules for solar cells, \" j. chem. phys. 131, 194701 ( 2009 ).", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6591373172179444, "token_count": 491, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 1, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:12.331271"} {"text": "josephson received the 1973 nobel prize in physics for discovery of the josephson effect, which occurs in two superconducting layers separated by an insulating oxide. under certain conditions current can pass through the insulator through tunneling of cooper pairs of electrons. the effect has been used to design superconducting quantum interference devices ( squid ) because switching is very fast, in the order of picoseconds. tunneling in the josephson junctions is very sensitive to magnetic fields and can therefore be used to measure extremely small magnetic fields with thresholds as low as tesla. josephson junctions are also used for other precision measurements. the standard volt is now defined as the voltage required to produce a frequency of 483, 597. 9 ghz in a josephson junction oscillator. a schematic diagram of a circuit with a josephson junction is shown below. the quantum effects can be modeled by the schrodinger equation, but it turns out that the circuit can also be modeled as a system with lumped parameters. let be the flux that is the integral of the voltage across the device, it follows from quantum theory [ feynman, 1970 ] that the current through the device is a function of the flux : where is a device parameter, and the josephson parameter is given by the circuit in the figure has two storage elements : the capacitor and the josephson junction. we choose the states as the voltage across the capacitor and the flux of the josephson junction. let, and be the currents through the resistor, the capacitor and the josephson junction. we have and a current balance gives which can be rewritten as combining this equation with equation for gives the following state equation for the circuit notice that apart from parameter values, this equation is identical to the equation for the inverted pendulum.", "subdomain_id": "subdomain_quantum_metrology", "similarity_score": 0.6973120328346555, "token_count": 373, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:12.689274"} {"text": "used during a concrete pour this small concrete block supports the rebar so it isn ' t forced to the bottom. abbreviation for the word document. 1. structure built into the water from the land providing a facility for boats to tie up. 2. loading area for goods at the rear of a commercial building. legal rule, principle or tenet. recorded materials including letters, photos, reproducible computer files, legal forms, etc. a document is any tangible information including letters, contracts, electronic or paper files, x - rays, receipts or other material evidence. list of documents that a lender requires from a potential borrower, such as paycheck stubs and credit card statements. any written evidence or tangible material that is coherent and related to the subject at hand. this includes documents, contracts, electronic and paper files, photographs and other non - oral evidence. tax imposed by some state and local governments to record property deeds and mortgages into the public records. polygon that is comprised of 12 angles and sides. solid figure comprised of 12 adjoining plane surfaces. heavy metal staple that makes a temporary connection between timbers. wooden fence with top corners of the vertical fence boards cut of at 45 - degree angles. dormer, which is in the shape of a small dog house. brick corners which project from a wall. modification in the amount of money involved for some justifiable reason. 1. any of several kinds of low, flat, wheeled frames for transporting heavy objects. 2. tool that holds a rivet at one end with a head hammered out of the other end. 3. a stick or board for stirring. bevel siding that is made with a rabbet or two - sided groove running along the edge which will overlap the top of the board below it. vertical piling structure which provides support to and contact with each other. a convex vaulted curvature often spherical in shape usually built atop of a building. they can be constructed of any material including masonry, wood, glass or steel and can be decorative or functional in nature. hemispherical ( 1 / 2 of a globe ) ceiling projecting upward. a person ' s permanent primary residence. alternately, the state where on has a permanent legal address. one who is considered the primary and principal estate administrator, being in the state where an individual was domiciled at the time of death. property that has an easement right through another adjoining property. the property through which the easement passes is considered to have the servient tenement. one to whom a", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6042884443313384, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:13.856504"} {"text": "_ 196 ; silverman, 1977 ). in other cases, the ability to discriminate without awareness is minimally above chance and confined to a small number of subjects ( merikle and reingold, 1992, p. 67 ). experiments have similarly failed to corroborate the phenomenon of repression. after reviewing this research holmes has concluded that at the present time there is no controlled laboratory evidence supporting the concept of repression ( holmes, 1990, p. 96 ). in summary, \" given the available evidence, it is still possible to argue that unconscious perceptual processes have not been shown to play any important role in directing human behavior \" ( merikle and reingold, 1992, p. 76 ). the foregoing critiques of unconscious processes indicate that psychological activity does not proceed by mechanisms independent of consciousness. psychological activity is activity of consciousness. psychological activity is also inseparable from social life. accordingly, the unconscious and its products ( dreams, slips of the tongue, and dysfunctional symptoms ) must be reconceptualized as integral to a social consciousness ( cf. lakoff, 1993 for a social cognitive analysis of dreams ). reconceptualization would be objectified in terminology. the term \" the unconscious \" would be abandoned because it connotes a physical thing or place outside consciousness. \" the unconscious \" would be replaced by \" unawareness \" which connotes a process or state rather than some sort of thing. in the remainder of this paper, i shall attempt to articulate a social conception of unawareness. the most fruitful perspective for guiding this endeavor is sociohistorical psychology. this school was founded by lev vygotsky, alexander luria, and alexei leontiev in the 1920 ' s unawareness according to sociohistorical psychology an overview of sociohistorical psychology space does not permit a full explication of sociohistorical psychology which can be found in ratner ( 1991, 1993a ), van der veer and valsiner ( 1991 ), and wertsch ( 1985a, 1985b ). the cornerstone of this viewpoint is that psychological functions depend upon real social life and bear its imprint. specifically, as individuals participate in economic, political, educational, religious, recreational, familial, and interpersonal activities they form social concepts. social concepts are socially shared knowledge, expectations, and evaluations of objects, people, and events. social concepts are the meanings that things have for a culture ( cf., lutz", "subdomain_id": "subdomain_quantum_mechanics", "similarity_score": 0.6173641425613728, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 5, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:14.746961"} {"text": ". the occupations determine the chief modes of satisfaction, the standards of success and failure. hence they furnish the working classifications and definitions of value ; they control the desire processes. moreover, they decide the sets of objects and relations that are important, and thereby provide the content or material of attention, and the qualities that are interestingly significant. the directions given to mental life thereby extend to emotional and intellectual characteristics. so fundamental and pervasive is the group of occupational activities that it affords the scheme or pattern of the structural organization of mental traits. occupations integrate special elements into a functioning whole. ( dewey, 1902, pp. 219 _ 220 ). moreover, social concepts structure somatic symptoms of psychological dysfunction. smith rosenberg ( 1972 ) concludes that hysterical conversion in nineteenth century middle - class women reflected the social value that women should be weak and spiritual rather than physically active. this social value led frustrated women to deaden their senses and immobilize their limbs, thereby exaggerating the normative gender ideal ( ratner, 1991, p. 274 ). kleinman and kleinman ( 1985, p. 434 ) similarly conclude that social values channel stress into somatic symptoms among precapitalist people and among lower class and rural groups in capitalist societies, while channeling stress into psychological symptoms among people living a more bourgeois life style. the defining features of social concepts are that they are shared by individuals and that they are rooted in concrete social activities of a social system. social concepts originate in particular praxis within particular sectors and classes ( or fields ) of a social system ( cf. bourdieu and wacquant, 1992, pp. 94 _ 115 ). but concepts may migrate to other sectors and classes and become quite general. economic concepts such as competition, individualism, and materialism may permeate family life, education, and the arts ( adorno, 1974 ; bronfenbrenner, 1979 ; henry, 1963 ; leach, 1993 ). religious ideas and scientific concepts may also achieve broad acceptance. wherever social concepts are accepted, they organize perception, emotions, motives, imagination, needs, and bodily functions. research on the cultural - cognitive basis of psychological functions has been summarized by shweder and sullivan ( 1993 ) and ratner ( 1991 ). this research demonstrates that psychological phenomena are integrated with each other, with social life, and with consciousness. unfortunately, little is known about the specific operations by which social concepts organize psychological phenomena. according to sociohistorical psychology, social concepts", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6140385852805134, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 7, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:14.749285"} {"text": "1991 ). this research demonstrates that psychological phenomena are integrated with each other, with social life, and with consciousness. unfortunately, little is known about the specific operations by which social concepts organize psychological phenomena. according to sociohistorical psychology, social concepts form psychological activity. they do not simply inhibit pre - social, pre - conscious functions. social concepts reorganize and reconstitute natural, infantile functions into psychological activity. natural functions do not retain their original character and continue to operate independently of social consciousness. in vygotsky ' s words, \" culture reworks all the child ' s natural behavior and carves anew his entire course of development \" ( 1993, p. 166 ). individual thoughts may be anti - social in content they may oppose certain social norms however they are not pre - social in origin. nor do social concepts influence the mind by operating on one function e. g., sexuality which, in turn, determines all other functions. social concepts directly form all psychological activity ; their impact is broad and systematic. in the same way, social concepts derive from the totality of social relations, not simply from a single domain of sexual mores. social influences on consciousness include economic, political, and other norms. in contrast to freud ' s psychology which narrowed the impact of society and consciousness on psychology, sociohistorical psychology expands their importance. sociohistorical psychological principles of unawareness although vygotsky did not propose a sociohistorical model of unawareness, the foregoing principles can be extended to develop one. indeed, an alternative conception of the unconscious would strengthen the critique which vygotsky levelled against psychoanalysis. while he was initially sympathetic to freud ' s materialistic approach and remained attracted to certain of freud ' s ideas, his mature work repudiated freud ' s overall conceptual system ( van der veer and valsiner, 1991, chapter five ). an exhaustive reconceptualization of the unconscious is beyond the scope of this paper. in what follows i shall only outline some fundamental concepts concerning the nature of unawareness. to begin with, sociohistorical psychology accepts freud ' s distinction between psychological phenomena which are temporarily beyond the focus of attention but are readily accessible ( the preconscious ), versus phenomena which are only accessible through extensive analysis ( the unconscious ). however, sociohistorical psychology constructs this distinction in terms that are significantly different from freud ' s. a more acceptable view of temporary unawareness is the ph", "subdomain_id": "subdomain_quantum_field_theory", "similarity_score": 0.6318806655075357, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 8, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:14.750263"} {"text": "outside explicit awareness. i shall not attempt to unravel the perplexing mystery of how the cognitive unconscious is acquired and controlled. instead i shall analyze another aspect of unawareness, namely ignorance of features of things and people. examples of this kind of unawareness are perceptual illusions which fool us into overlooking the features of physical objects. we may similarly overlook psychological characteristics of oneself and other people such as motives, emotions, abilities, and attitudes. this ignorance of attributes is what freud ' s concept of the unconscious denoted. in what follows i offer a sociohistorical psychological explanation of this kind of unawareness. sociohistorical psychology explains unawareness of people ' s psychological qualities in terms of the social concepts which structure perception. as discussed earlier, social concepts function as cognitive schemas which structure our mental processes and sensitize us to certain things while desensitizing us to other things. in this way social concepts create unawareness as well as awareness. for example, the social value of romantic love leads to exaggerating the lover ' s attractiveness and obscuring faults. the social value of youthfulness leads to exaggerating the capabilities of young people and obscuring their limits. conversely, the capabilities and wisdom of old people are obscured and denigrated. from this point of view, unawareness and awareness are two sides of the same janus figure. unawareness is the obverse of awareness its dialectical opposite. unawareness is not a separate system as freud claimed. unawareness is due to misperception and it is explainable in the same terms as perceptual illusions : the perceiver invokes incorrect assumptions about a psychological quality and these erroneous assumptions misinform him about its properties, relationships, and origins. asch ( 1952, p. 604 ) explained this as follows : \" the forcible exclusion of data ( and goals ) from the center of awareness need not involve the operation of unconscious forces in freud ' s sense. what is of most consequence at the social level is that one does not see facts in their proper context, or that one does not face them, or that one violently stresses certain events at the expense of others, operations which produce misstructuring or distortion in understanding and feeling. \" explaining unawareness in the same terms as misperception has several virtues. it sharpens our understanding of unawareness by employing accepted, detailed concepts from the study of \" perception and cognition. it also maintains a parsimonious account of", "subdomain_id": "subdomain_quantum_mechanics", "similarity_score": 0.6318665823561999, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 10, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:14.754422"} {"text": ". \" explaining unawareness in the same terms as misperception has several virtues. it sharpens our understanding of unawareness by employing accepted, detailed concepts from the study of \" perception and cognition. it also maintains a parsimonious account of several phenomena with relatively few concepts, which is one of the goals of science. perception and recollection of psychological characteristics are distorted by inadequate concepts. * distortion occurs in two ways. in certain cases, conceptual schemata lead to misperceiving an enduring quality. for instance, a person of low intelligence believes himself to be bright. his low intelligence persists despite his overestimation. in other cases, conceptual schemata actually transform a psychological quality. for example, an angry person who conceives of herself as mild - mannered may not perceive her own angry state as anger. anger will be misconstrued as equanimity and the latter will be experienced. anger may have been momentarily experienced but it was transformed in the act of reflection and no longer exists. of course, the brief experience of anger may be encoded in memory and remembered as a previous experience. however, in all likelihood, the anger will not be recalled because it was so fleeting and discordant with the individual ' s self image. * * both kinds of misperception leave the subject unaware of the original quality. in neither case does the original quality remain in the subject ' s \" unconscious. \" low intelligence is not \" unconsciously \" known to the subject, any more than the real properties of objects are \" unconsciously \" known in the case of perceptual illusions. social concepts function as filters which distort the character of a psychological quality just as they can distort the properties of physical objects. distortion is caused by conceptual limitations of social values, not, as freudians claim, by the subject ' s fear of facing his or her own unacceptable true ideas. to say that social concepts structure awareness means that all perceptual activity is biased toward certain things and away from others. perception can never be fully responsive to everything. it must be insensitive to, or unaware of, phenomena which fall beyond its parameters. although all social concepts produce some unawareness, the content and extensiveness of unawareness vary. certain concepts may desensitize us to things which are quite valuable, and we will wish to replace these concepts with others that sensitize us to the important things. we shall return to this subject in the section on overcoming unawareness", "subdomain_id": "subdomain_quantum_mechanics", "similarity_score": 0.6405602453715058, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 11, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:14.755456"} {"text": "superficiality, intolerance and insecurity. he could not see that other people were sensitive and justifiably offended by his arrogance. fictitious postulates were necessary to uphold the integrity of his ideological system. george ' s competitive social concept additionally led him to misconstrue the interrelation of certain qualities in himself and others. his competitive schema did not allow him to perceive his awkwardness as a causal factor which pushed people away from him. this would have implied some weakness in george which was inconceivable to his viewpoint. his competitive schema made george reverse the causal relationship and postulate that other people had estranged him, thereby producing his awkwardness. another social concept, atomism, compounded george ' s unawareness. atomism is the belief that phenomena are discrete, independent atoms. atomism, like competition, is rooted in our capitalistic socioeconomic system. the struggle among independent entrepreneurs to maximize their private wealth, unbridled by social coordination, cooperation, or obligation fosters the belief that the world is composed of separate, independent elements ( macpherson, 1962 ). when people regard themselves in these atomistic terms they feel internally fragmented and detached from other people. detachment desensitizes us to other people ' s needs, perceptions, emotions, reasoning, and motives. it also obscures social influences that mold behavior. these effects of atomism can be seen in george ' s psychology. he certainly felt estranged from people, and he was terribly insensitive to their perceptions, emotions, and personality. george ' s atomistic thinking also obscured the interrelationships among his psychological activities. it focused his attention on individual acts and distracted him from detecting consistencies among them. for example, it never occurred to george that shoplifting, spreading rumors, resenting other people ' s success, and lecturing to them all embodied a common tendency to make himself superior. the dissimilar details of these acts overshadowed similar elements. when george succeeded with shoplifting he was absorbed in the success of obtaining a free object. when he lectured people he was absorbed in presenting a clever idea. the different acts each generated a gleeful superiority, but because the acts were not compared together, this feeling was not drawn out as a common essential quality. * * experimental psychologists have reported similar awareness of particular events but unawareness of their relations. kenneth bowers ( 1984 ) described an experiment where he selectively reinforced subjects ' preference for certain pictures. this reinforcement led to dramatic changes in preference for", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.60325485613388, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 14, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:14.761961"} {"text": "quality. * * experimental psychologists have reported similar awareness of particular events but unawareness of their relations. kenneth bowers ( 1984 ) described an experiment where he selectively reinforced subjects ' preference for certain pictures. this reinforcement led to dramatic changes in preference for some subjects. these subjects were aware of the reinforcement, but they failed to comprehend the effect that the reinforcement had on their preferences : they insisted that their preferences were independent of the reinforcement. nisbett and wilson ( 1977 ) summarize additional experimental demonstrations of people being aware of factual events but unaware of the causal relation between them. subjects whose behavior has been systematically modified by manipulating certain variables misattribute their behavior to other factors. a final effect that atomistic thinking had on george ' s unawareness was to blind him to the relationship that his behavior had to the broad society. he construed his behavior in individual terms and was oblivious to social factors, including social concepts, which had influenced his action. it is important to understand that social concepts restructured george ' s consciousness to blot out the foregoing characteristics and relationships. george could not entertain these issues because they lay outside his conceptual framework, not because he was afraid to face them. he was unaware of them because they were inconceivable, not because they were unacceptable. knowledge of these issues did not surreptitiously exist in george ' s \" unconscious \" insulated from social consciousness. rather, competitive and atomistic schemata structured the psyche so thoroughly as to preclude knowledge from existing at any level. the true character and relationships of psychological acts were unknown to george without being unconscious in the freudian sense. according to sociohistorical psychology, unawareness is not the product of negatively blocking an existing idea. it results from positively structuring perception in a certain way that misconstrues qualities and their relationships. unawareness depends upon a certain kind of awareness. for freud, understanding unawareness does not require understanding consciousness. the only aspect of consciousness that is relevant is that it rejects a certain idea as unacceptable. for sociohistorical psychology, understanding unawareness depends upon understanding the specific social concepts of consciousness which value and devalue certain qualities of people, relate and differentiate particular attributes, and which construe events in a certain manner. george ' s conceptual framework not only desensitized him to certain characteristics ( e. g., weaknesses ) and relationships ( e. g., patterns ) of psychological activity. his conceptual framework also obscured the causes of", "subdomain_id": "subdomain_quantum_mechanics", "similarity_score": 0.6014153591761605, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 15, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:14.763465"} {"text": ". social concepts are the means by which we produce psychological phenomena they are our \" psychological means of production \" and \" psychological mode of production. \" social concepts not only determine our perceptions, emotions, imagination, and needs, but our unawareness as well. several caveats must be mentioned concerning social ideology and psychology. although ideology is constructed and sustained in social institutions, individuals creatively apply ideology to their particular personal situation. we have seen how hysterical women exaggerated social values to construct psychological symptoms. george was similarly creative in using competition to explain his estrangement. he postulated weaknesses in his peers which led them to reject him. however, he could have utilized the concept of competitiveness to explain his social estrangement in another way. he might have regarded himself as a loser with less ability than his successful peers. blaming oneself for failure is as compatible with competitive ideology as is blaming others. an ideology has numerous strands and the individual may select among them. * the failure of naive individuals to identify the social pattern, significance, and origin of their psychological functions means that a sociohistorical analysis must be made by a culturally sensitive observer rather than by the subject himself. phenomenological reports of subjective experience will not explicate the sociohistorical character of that naive experience. as sartre ( 1960 / 1976, p. 225 ) said, \" there is no a priori reason why the... result [ of social events ] should be understood by the agent : everything depends upon the instruments of thought provided for him by his period, class, and historical circumstances. \" while a sociohistorical character is implicit in all experience, it can only be explicated by an analyst who is knowledgeable about society and can draw out the manner in which experience reflects ( and contradicts ) social values and norms ( cf. ratner, 1993b ). another caveat is that predominant social values such as competitiveness and atomism do not affect all individuals equally. people have different social experiences and they exercise some selection in adopting social concepts. why a particular individual adopts a particular form of a particular ideology is not addressed here. i am only concerned with the social parameters within which individual variations occur. the social parameters allow for prediction of general psychological trends among masses of people, but not for prediction of any one individual. an individual ' s psychology is composed of social concepts but which particular ones must be discovered after he or she makes the selection. we have seen that unawareness of psychological qualities and relationships is shaped by social", "subdomain_id": "subdomain_quantum_field_theory", "similarity_score": 0.6290343821845754, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 17, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:14.765839"} {"text": ", but not for prediction of any one individual. an individual ' s psychology is composed of social concepts but which particular ones must be discovered after he or she makes the selection. we have seen that unawareness of psychological qualities and relationships is shaped by social influences of which we are also unaware. consequently, overcoming unawareness requires identifying the social influences which produce it, repudiating these influences, and ultimately replacing them with others that enhance sensitivity. the social concepts which generate unawareness can be gleaned from a social analysis of conscious activity. consciousness and unawareness are two sides of the same social concept. the analyst must begin with the social concepts that inform conscious activity and proceed to identify the unawareness which those same concepts produce. for example, george ' s arrogance and stealing were forms of competitiveness, and the latter was responsible for his ignorance about self and others. once conscious activity is construed in social terms, unawareness can be also. reconceptualizing cognitive concepts and behavior in social terms such as competition, materialism, individualism, reification, and alienation restructures understanding because language produces meaning. this meaning - giving function of language was one of vygotsky ' s central concerns. he believed that, \" speech does not merely serve as the expression of developed thought. thought is restructured as it is transformed into speech. it is not expressed but completed in the word \" ( vygotsky, 1987b, p. 251 ; cf. ratner, 1991, pp. 36 _ 37 ). recasting personal lived experience as reflecting social concepts * provides the greatest potential for identifying, repudiating, and eliminating the causes of personal unawareness. identifying social concepts in the psyche would make george aware of the numerous ways in which he thinks and acts competitively, and how these combine to make him unaware of important issues. * dilthey was an important advocate of this kind of recasting ( cf. - - ermarth, 1978, pp. 226 _ 227 - - ). george would then be in a position to systematically repudiate these psychological manifestations of competition which impair his awareness. identifying social concepts would additionally enable george to identify their origins and manifestations in diverse sectors of society. george could discern that his personal competitiveness was promulgated by competitiveness in the economy, in the media, in school, and elsewhere. he would then be in a position to systematically repudiate the social origins of his destructive behavior and his unawareness", "subdomain_id": "subdomain_quantum_mechanics", "similarity_score": 0.6101472176605555, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 18, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:14.767607"} {"text": "facilitate awareness of the social reasons for his behavior. new social concepts would therefore restructure george ' s psychological field. elements would become reorganized into new relationships, causal vectors would be reversed, and characteristics which appeared immutable might be perceived as changeable. since social concepts emanate from social practice, new beneficent concepts can only be successfully implemented if they are supported by a new social practice, just as debilitating social concepts can only be uprooted if their social basis is repudiated. sociohistorical psychology is unique in emphasizing the social changes necessary to enhance awareness. nonsocial analyses ignore the full range of social and psychological influences which sustain unawareness. nonsocial analyses also pay little attention to reconstructing new social practices and concepts that must replace the debilitating ones. this makes overcoming unawareness extremely difficult because the sustaining context continues to perpetuate it. paradoxically, overlooking social systems reifies behavior as natural, while recognizing social origins and social forms of behavior enable them to be altered. social practices and concepts can be altered for a variety of reasons. one reason is that social practices and concepts may produce behavior that contradicts them. for example, competition is designed to motivate winning behavior, but it often produces losing behavior. people who consistently lose may see the contradiction between what the social value promises and what it actually produces. the social value cannot deliver its own definition of success. this internal contradiction may lead to questioning the viability of the social concept. another reason for altering social concepts is the \" external \" contradiction that occurs between different concepts. every society has numerous social concepts which reflect activities from different social sectors. in the united states, competition is contradicted by religious, family, and educational values. internal and external contradictions among social concepts can generate psychic strife and the desire to change behavior. there is no need to postulate a non - social segment of self which challenges and improves social concepts. according to sociohistorical psychology, psychological qualities are not unknown because they are submerged below conscious awareness. they are unknown because they lie beyond the scope of our conceptual schemata. psychological insight will not be achieved by a depth psychology which excavates impulses from inside the mind. insight requires breadth psychology which develops new social concepts and social relations. this is what vygotsky ( 1987a, p. 77 ) had in mind when he said, \" it is not the depths but the heights of the personality that are decisive for understanding the reactions of", "subdomain_id": "subdomain_quantum_field_theory", "similarity_score": 0.6301666062975944, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 20, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:14.771149"} {"text": "carl e. wieman, wendy k. adams, and katherine k. perkins this item is a 2008 article in science magazine that highlights research done by the physics education technology project on how students use interactive simulations to meet their learning needs. the article discusses research by the phet project on the design and use of simulations in a variety of educational settings. results indicate that concept mastery is measurably improved when students explore simulations in addition to traditional labs. in addition, use of simulations was correlated with higher student motivation and active involvement in the learning process. the phet project provides technology - based resources and information for physics education, most notably, simulations on a wide range of topics. the simulations are developed in conjunction with careful research to enhance their effectiveness as learning tools. metadata instance created february 10, 2009 by caroline hall july 8, 2010 by lyle barbato last update when cataloged : october 31, 2008 this resource is part of a physics front topical unit. topic : wave energy unit title : teaching about waves and wave energy a must - read article from science magazine, this item summarizes the research efforts of the phet project on the use of interactive simulations in the physics classroom. results indicate that concept mastery is measurably improved when students explore simulated physical processes in addition to traditional labs. use of simulations was also correlated to higher student motivation and active involvement in the learning process. c. wieman, w. adams, and k. perkins, phet research : simulations that enhance learning, science 322 ( 5902 ), 682 ( 2008 ), < http : / / phet. colorado. edu / publications / phet _ simulations _ that _ enhance _ learning. pdf >. wieman, c., adams, w., & perkins, k. ( 2008, october 31 ). phet research : simulations that enhance learning. science, 322 ( 5902 ), 682 - 683. retrieved may 23, 2013, from http : / / phet. colorado. edu / publications / phet _ simulations _ that _ enhance _ learning. pdf % 0 journal article % a wieman, carl % a adams, wendy % a perkins, katherine % d october 31, 2008 % t phet research : simulations that enhance learning % j science % v 322 % n 5902 % p 682 - 683 % 8 october 31, 2008 % u http : / / phet. colorado. edu / publications / phet _ simulations _ that _ enhance _ learning. pdf", "subdomain_id": "subdomain_quantum_simulation", "similarity_score": 0.60711522905858, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.072140"} {"text": "the item that binds the two hard - to - combine ingredients. common emulsifiers are mustard and egg yolks. glaze : 1. a 90 % reduction of stock. 2. a thin glossy coating applied to foods. a reduction or aspic can cover savory foods. anything from melted chocolate to thin icings can cover pastries and cakes. v. to apply a thin shiny coating to food. infusion : the extraction of flavor from a food in a hot liquid ( below the boiling point ). usually refers to teas and coffees, but can also apply to cooking ( like the pistachio cream or olive oils that are infused with herbs ). infusion : the extraction of flavor from a food in a hot liquid ( below the boiling point ). usually refers to teas and coffees, but can also apply to cooking ( like the pistachio cream or olive oils that are infused with herbs ). - j - marrow : a soft, fatty tissue found in the hollow center of an animal ' s bone - - particularly plentiful in the shin and leg bones. considered a delicacy in europe, marrow is light and digestible with the same amount of calories as beef fat. it can be cooked in the bone, removed, and eaten. and it can be used in soups and stews for flavor and body. mince : to cut food into very small pieces. the terms \" finely chopped \" and \" minced \" are interchangeable. mirepoix : [ mihr - pwah ] a mixture of diced carrots, onions, celery, and herbs sauteed in butter. mirepoix is used in almost all soups, sauces, and stews as a base flavor. it is also used as a bed to braise meats, poultry and fish. mount : a technique where small pieces of cold, unsalted butter are whisked into a sauce just before serving. mounting gives sauces texture and flavor as well as a glossy look. non - reactive : any cooking material that won ' t react ( by discoloring or changing the taste ) with acidic foods. glass and stainless steel are the most common non - reactive materials. non - reactive pan or bowl : any non - porous material that does not impart a flavor or alter a color in food. this includes glass, stainless steel, glazed ceramic, or enamel. - p - poach : to cook food gently in hot liquid that", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6345166815117922, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 1, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.091395"} {"text": "or bowl : any non - porous material that does not impart a flavor or alter a color in food. this includes glass, stainless steel, glazed ceramic, or enamel. - p - poach : to cook food gently in hot liquid that ' s just below the boiling point. liquids can vary from broths, to water, to syrups. polenta : [ po - lehn - tah ] an italian cornmeal mush that is often cooled and then fried, grilled, broiled, or baked. prosciutto : [ proh - shoo - toh ] this \" ham \" is italy ' s gift to the food world. the cities of parma and san daniele ( where it ' s mainly produced ) argue over whose is better. its production is a secret. it ' s first seasoned and salt - cured ( but not smoked ). then it ' s air - dried, pressed, and sold thinly sliced. the best hams are aged 18 to 24 months. - r - reduce : applied to cooking, this means to boil a liquid until its volume is reduced by evaporation. this thickens the liquid and intensifies the flavor. reduction : a process used to increase and intensify the flavor of a liquid. this is done by rapidly boiling a liquid to decrease its volume through evaporation. this concentrates the flavor, so season a reduction after it ' s made - - not before. render : the melting of animal fat over low heat so it separates from any connective tissue. this tissue turns crisp and brown ( known as crackling ) and the clarified ( clear ) fat is further processed by straining. to cook fatty meats, such as bacon or spare ribs, until the fat melts. resting : heat drives meat ' s juices from the surface when it cooks. letting meat \" rest \" before slicing lets these juices seep back towards the surface ( liquids always take the path of least resistance ). the result is a more flavorful piece of meat. ribbon : when a sauce thickens enough that when lifted, it falls in wide bands. also, when sauce is thick enough that while stirred with a whisk, it leaves trails that expose the bottom of the pan or mixing bowl. ricer : a kitchen gadget that looks like a big garlic press. great for mashing potatoes. this device, also called a potato ricer, forces cooked foods like turnips saute : [ saw - tay ] in french", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6084891469439044, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 2, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.093461"} {"text": "net force, also known as resultant force, is a vector quantity produced when two or more forces act upon one object. the concept of net force is the same as the mathematical concept of vector addition. let ' s talk about net force. this is also sometimes called resultant force, those two words are used interchangenly and basically what this is, is the vector that ' s produced when 2 or more forces act together. remember anything that has distance and magnitude we can depict as a vector. so let ' s look at a couple of examples or how you can calculate a net force on an object okay. let ' s take for example a helicopter, you may notice when helicopters go up and down they are completely vertical right? but when they want to go forward they need to actually tilt, that ' s to create this thrust where they ' re pushing air in that direction which is causing a force in that direction. i ' m going to call that f1 okay but how come that a helicopter that ' s tilted in this direction isn ' t going up in that direction? well that ' s because there ' s a second force acting on that helicopter okay and that ' s the force of gravity. i ' m going to call that f2, okay. so what ' s the overall force going to be on this helicopter? well i have to add my 2 vectors together and i can do that easily by just taking this one and pointing it head to tail to the first one. so if i put my f2 right here i can see that my resultant vector which we ' ll call fa is causing it to move in a horizontal way to the earth. okay, so just adding vectors that helps us figure out the true vector okay. let ' s say i ' m playing golf another example we might see i ' m going to tee off from right here and there ' s my hole and i want to aim right for that whole okay and i ' m going to hit a shot that goes right about there okay. now if that was my only force acting on that ball that would be a pretty good shot right. but let ' s say there ' s a wind and let ' s say that wind is blowing in this direction okay. so f1 is the force applied to my golf club on the ball, f2 is the wind okay. that is going to push the ball in this direction, okay so i put f2 right there and i add these two vectors together and i actually get something that looks like that f actual okay and now i ' m", "subdomain_id": "subdomain_quantum_field_theory", "similarity_score": 0.6343968331097765, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.531015"} {"text": "in mathematics, computer science, or management science, mathematical optimization ( alternatively, optimization or mathematical programming ) is the selection of a best element ( with regard to some criteria ) from some set of available alternatives. in the simplest case, an optimization problem consists of maximizing or minimizing a real function by systematically choosing input values from within an allowed set and computing the value of the function. the generalization of optimization theory and techniques to other formulations comprises a large area of applied mathematics. more generally, optimization includes finding \" best available \" values of some objective function given a defined domain, including a variety of different types of objective functions and different types of domains. optimization problems an optimization problem can be represented in the following way - given : a function f : a r from some set a to the real numbers - sought : an element x0 in a such that f ( x0 ) \u2264 f ( x ) for all x in a ( \" minimization \" ) or such that f ( x0 ) \u2265 f ( x ) for all x in a ( \" maximization \" ). such a formulation is called an optimization problem or a mathematical programming problem ( a term not directly related to computer programming, but still in use for example in linear programming \u2013 see history below ). many real - world and theoretical problems may be modeled in this general framework. problems formulated using this technique in the fields of physics and computer vision may refer to the technique as energy minimization, speaking of the value of the function f as representing the energy of the system being modeled. typically, a is some subset of the euclidean space rn, often specified by a set of constraints, equalities or inequalities that the members of a have to satisfy. the domain a of f is called the search space or the choice set, while the elements of a are called candidate solutions or feasible solutions. the function f is called, variously, an objective function, cost function ( minimization ), indirect utility function ( minimization ), utility function ( maximization ), or, in certain fields, energy function, or energy functional. a feasible solution that minimizes ( or maximizes, if that is the goal ) the objective function is called an optimal solution. by convention, the standard form of an optimization problem is stated in terms of minimization. generally, unless both the objective function and the feasible region are convex in a minimization problem, there may be several local minima, where a local minimum x * is defined as a point", "subdomain_id": "subdomain_quantum_simulation", "similarity_score": 0.6438996023701558, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.674639"} {"text": "- optimal control theory is a generalization of the calculus of variations. - dynamic programming studies the case in which the optimization strategy is based on splitting the problem into smaller subproblems. the equation that describes the relationship between these subproblems is called the bellman equation. - mathematical programming with equilibrium constraints is where the constraints include variational inequalities or complementarities. multi - objective optimization adding more than one objective to an optimization problem adds complexity. for example, to optimize a structural design, one would want a design that is both light and rigid. because these two objectives conflict, a trade - off exists. there will be one lightest design, one stiffest design, and an infinite number of designs that are some compromise of weight and stiffness. the set of trade - off designs that cannot be improved upon according to one criterion without hurting another criterion is known as the pareto set. the curve created plotting weight against stiffness of the best designs is known as the pareto frontier. a design is judged to be \" pareto optimal \" ( equivalently, \" pareto efficient \" or in the pareto set ) if it is not dominated by any other design : if it is worse than another design in some respects and no better in any respect, then it is dominated and is not pareto optimal. the choice among \" pareto optimal \" solutions to determine the \" favorite solution \" is delegated to the decision maker. in other words, defining the problem as multiobjective optimization signals that some information is missing : desirable objectives are given but not their detailed combination. in some cases, the missing information can be derived by interactive sessions with the decision maker. multi - objective optimization problems have been generalized further to vector optimization problems where the ( partial ) ordering is no longer given by the pareto ordering. multi - modal optimization optimization problems are often multi - modal ; that is, they possess multiple good solutions. they could all be globally good ( same cost function value ) or there could be a mix of globally good and locally good solutions. obtaining all ( or at least some of ) the multiple solutions is the goal of a multi - modal optimizer. classical optimization techniques due to their iterative approach do not perform satisfactorily when they are used to obtain multiple solutions, since it is not guaranteed that different solutions will be obtained even with different starting points in multiple runs of the algorithm. evolutionary algorithms are however a very popular approach to obtain multiple solutions in a multi -", "subdomain_id": "subdomain_quantum_simulation", "similarity_score": 0.6224307044264278, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 4, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.684559"} {"text": "evaluation of hessians. - gradient descent ( alternatively, \" steepest descent \" or \" steepest ascent \" ) : a ( slow ) method of historical and theoretical interest, which has had renewed interest for finding approximate solutions of enormous problems. - subgradient methods - an iterative method for large locally lipschitz functions using generalized gradients. following boris t. polyak, subgradient \u2013 projection methods are similar to conjugate \u2013 gradient methods. - bundle method of descent : an iterative method for small \u2013 medium sized problems with locally lipschitz functions, particularly for convex minimization problems. ( similar to conjugate gradient methods ) - ellipsoid method : an iterative method for small problems with quasiconvex objective functions and of great theoretical interest, particularly in establishing the polynomial time complexity of some combinatorial optimization problems. it has similarities with quasi - newton methods. - reduced gradient method ( frank \u2013 wolfe ) for approximate minimization of specially structured problems with linear constraints, especially with traffic networks. for general unconstrained problems, this method reduces to the gradient method, which is regarded as obsolete ( for almost all problems ). - simultaneous perturbation stochastic approximation ( spsa ) method for stochastic optimization ; uses random ( efficient ) gradient approximation. - methods that evaluate only function values : if a problem is continuously differentiable, then gradients can be approximated using finite differences, in which case a gradient - based method can be used. global convergence more generally, if the objective function is not a quadratic function, then many optimization methods use other methods to ensure that some subsequence of iterations converges to an optimal solution. the first and still popular method for ensuring convergence relies on line searches, which optimize a function along one dimension. a second and increasingly popular method for ensuring convergence uses trust regions. both line searches and trust regions are used in modern methods of non - differentiable optimization. usually a global optimizer is much slower than advanced local optimizers ( such as bfgs ), so often an efficient global optimizer can be constructed by starting the local optimizer from different starting points. - memetic algorithm - differential evolution - differential search algorithm matlab code - link has been provided in civicioglu, p., ( 2012 ). - dynamic relaxation - genetic algorithms - hill climbing - nelder - mead simplicial heuristic : a popular heuristic for approximate minimization", "subdomain_id": "subdomain_quantum_simulation", "similarity_score": 0.6352000952479351, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 8, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.689066"} {"text": "- link has been provided in civicioglu, p., ( 2012 ). - dynamic relaxation - genetic algorithms - hill climbing - nelder - mead simplicial heuristic : a popular heuristic for approximate minimization ( without calling gradients ) - particle swarm optimization - artificial bee colony optimization - simulated annealing - tabu search - reactive search optimization ( rso ) implemented in lionsolver mechanics and engineering problems in rigid body dynamics ( in particular articulated rigid body dynamics ) often require mathematical programming techniques, since you can view rigid body dynamics as attempting to solve an ordinary differential equation on a constraint manifold ; the constraints are various nonlinear geometric constraints such as \" these two points must always coincide \", \" this surface must not penetrate any other \", or \" this point must always lie somewhere on this curve \". also, the problem of computing contact forces can be done by solving a linear complementarity problem, which can also be viewed as a qp ( quadratic programming ) problem. many design problems can also be expressed as optimization programs. this application is called design optimization. one subset is the engineering optimization, and another recent and growing subset of this field is multidisciplinary design optimization, which, while useful in many problems, has in particular been applied to aerospace engineering problems. economics is closely enough linked to optimization of agents that an influential definition relatedly describes economics qua science as the \" study of human behavior as a relationship between ends and scarce means \" with alternative uses. modern optimization theory includes traditional optimization theory but also overlaps with game theory and the study of economic equilibria. the journal of economic literature codes classify mathematical programming, optimization techniques, and related topics under jel : c61 - c63. in microeconomics, the utility maximization problem and its dual problem, the expenditure minimization problem, are economic optimization problems. insofar as they behave consistently, consumers are assumed to maximize their utility, while firms are usually assumed to maximize their profit. also, agents are often modeled as being risk - averse, thereby preferring to avoid risk. asset prices are also modeled using optimization theory, though the underlying mathematics relies on optimizing stochastic processes rather than on static optimization. trade theory also uses optimization to explain trade patterns between nations. the optimization of market portfolios is an example of multi - objective optimization in economics. since the 1970s, economists have modeled dynamic decisions over time using control theory. for example, microeconomists use dynamic", "subdomain_id": "subdomain_quantum_simulation", "similarity_score": 0.6402960708205362, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 9, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.690089"} {"text": "of economic science, macmillan, p. 16. - a. k. dixit ( 1990 ). optimization in economic theory, 2nd ed., oxford. description and contents preview. - a. g. malliaris ( 2008 ). \" stochastic optimal control, \" the new palgrave dictionary of economics, 2nd edition. abstract. - julio rotemberg and michael woodford ( 1997 ), \" an optimization - based econometric framework for the evaluation of monetary policy. nber macroeconomics annual, 12, pp. 297 - 346. - from the new palgrave dictionary of economics ( 2008 ), 2nd edition with abstract links : \u2022 \" numerical optimization methods in economics \" by karl schmedders \u2022 \" convex programming \" by lawrence e. blume \u2022 \" arrow \u2013 debreu model of general equilibrium \" by john geanakoplos. further reading undergraduate level - bradley, s. ; hax, a. ; magnanti, t. ( 1977 ). applied mathematical programming. addison wesley. - rardin, ronald l. ( 1997 ). optimization in operations research. prentice hall. p. 919. isbn 0 - 02 - 398415 - 5. unknown parameter - strang, gilbert ( 1986 ). introduction to applied mathematics. wellesley, ma : wellesley - cambridge press ( strang ' s publishing company ). pp. xii + 758. isbn 0 - 9614088 - 0 - 4. mr 870634. graduate level - magnanti, thomas l. ( 1989 ). \" twenty years of mathematical programming \". in cornet, bernard ; tulkens, henry. contributions to operations research and economics : the twentieth anniversary of core ( papers from the symposium held in louvain - la - neuve, january 1987 ). cambridge, ma : mit press. pp. 163 \u2013 227. isbn 0 - 262 - 03149 - 3. mr 1104662. - minoux, m. ( 1986 ). mathematical programming : theory and algorithms ( translated by steven vajda from the ( 1983 paris : dunod ) french ed. ). chichester : a wiley - interscience publication. john wiley & sons, ltd. pp. xxviii + 489. isbn 0 - 471 - 90170 - 9. mr 2571910. ( 2008 second ed., in french : programmation mathematique : theorie et algorithmes. editions tec & doc, paris, 2008", "subdomain_id": "subdomain_quantum_simulation", "similarity_score": 0.6039899046694306, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 11, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.695662"} {"text": "489. isbn 0 - 471 - 90170 - 9. mr 2571910. ( 2008 second ed., in french : programmation mathematique : theorie et algorithmes. editions tec & doc, paris, 2008. xxx + 711 pp. isbn 978 - 2 - 7430 - 1000 - 3. unknown parameter - nemhauser, g. l. ; rinnooy kan, a. h. g. ; todd, m. j., eds. ( 1989 ). optimization. handbooks in operations research and management science 1. amsterdam : north - holland publishing co. pp. xiv + 709. isbn 0 - 444 - 87284 - 1. mr 1105099. - j. e. dennis, jr. and robert b. schnabel, a view of unconstrained optimization ( pp. 1 \u2013 72 ) ; - donald goldfarb and michael j. todd, linear programming ( pp. 73 \u2013 170 ) ; - philip e. gill, walter murray, michael a. saunders, and margaret h. wright, constrained nonlinear programming ( pp. 171 \u2013 210 ) ; - ravindra k. ahuja, thomas l. magnanti, and james b. orlin, network flows ( pp. 211 \u2013 369 ) ; - w. r. pulleyblank, polyhedral combinatorics ( pp. 371 \u2013 446 ) ; - george l. nemhauser and laurence a. wolsey, integer programming ( pp. 447 \u2013 527 ) ; - claude lemarechal, nondifferentiable optimization ( pp. 529 \u2013 572 ) ; - roger j - b wets, stochastic programming ( pp. 573 \u2013 629 ) ; - a. h. g. rinnooy kan and g. t. timmer, global optimization ( pp. 631 \u2013 662 ) ; - p. l. yu, multiple criteria decision making : five basic concepts ( pp. 663 \u2013 699 ). - shapiro, jeremy f. ( 1979 ). mathematical programming : structures and algorithms. new york : wiley - interscience [ john wiley & sons ]. pp. xvi + 388. isbn 0 - 471 - 77886 - 9. mr 544669. - spall, j. c. ( 2003 ), introduction to stochastic search and optimization : estimation, simulation, and control,", "subdomain_id": "subdomain_quantum_simulation", "similarity_score": 0.6068683158921377, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 12, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.696567"} {"text": "+ 388. isbn 0 - 471 - 77886 - 9. mr 544669. - spall, j. c. ( 2003 ), introduction to stochastic search and optimization : estimation, simulation, and control, wiley, hoboken, nj. continuous optimization - mordecai avriel ( 2003 ). nonlinear programming : analysis and methods. dover publishing. isbn 0 - 486 - 43227 - 0. - bonnans, j. frederic ; gilbert, j. charles ; lemarechal, claude ; sagastizabal, claudia a. ( 2006 ). numerical optimization : theoretical and practical aspects. universitext ( second revised ed. of translation of 1997 french ed. ). berlin : springer - verlag. pp. xiv + 490. doi : 10. 1007 / 978 - 3 - 540 - 35447 - 5. isbn 3 - 540 - 35445 - x. mr 2265882. - bonnans, j. frederic ; shapiro, alexander ( 2000 ). perturbation analysis of optimization problems. springer series in operations research. new york : springer - verlag. pp. xviii + 601. isbn 0 - 387 - 98705 - 3. mr 1756264. - boyd, stephen p. ; vandenberghe, lieven ( 2004 ). convex optimization ( pdf ). cambridge university press. isbn 978 - 0 - 521 - 83378 - 3. retrieved october 15, 2011. - jorge nocedal and stephen j. wright ( 2006 ). numerical optimization. springer. isbn 0 - 387 - 30303 - 0. - ruszczynski, andrzej ( 2006 ). nonlinear optimization. princeton, nj : princeton university press. pp. xii + 454. isbn 978 - 0691119151. mr 2199043. combinatorial optimization - r. k. ahuja, thomas l. magnanti, and james b. orlin ( 1993 ). network flows : theory, algorithms, and applications. prentice - hall, inc. isbn 0 - 13 - 617549 - x. - william j. cook, william h. cunningham, william r. pulleyblank, alexander schrijver ; combinatorial optimization ; john wiley & sons ; 1 edition ( november 12, 1997 ) ; isbn 0 - 471 - 55894 - x. - gondran, michel ; minoux, michel ( 1984 ). graphs and algorithms", "subdomain_id": "subdomain_quantum_simulation", "similarity_score": 0.6014620054690982, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 13, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.697509"} {"text": "| s - block in the periodic table | | | this article is in a list format that may be better presented using prose. ( march 2013 ) | the s - block is a block in the periodic table that consists of the first two groups, namely the alkali metals and the alkaline earth metals. the elements in the s - block generally exhibit well - defined trends in their physical and chemical properties, changing steadily moving down the groups. their properties can be most readily explained in terms of their electron configuration, with their valence electrons occupying s - orbitals. by this definition, hydrogen and helium are sometimes also considered to be part of the s - block. the modern periodic law states that an element ' s chemical and physical properties is a periodic function of its atomic number. the long form of the periodic table is based on modern periodic law. the long form is divided into four blocks, s, p, d, and f. in an atom of an s - block element, the last electron enters the s - orbital of the outermost electron shell : - group 1 : - group 2 : - beryllium ( z = 4 ), magnesium ( z = 12 ), calcium ( z = 20 ), strontium ( z = 38 ), barium ( z = 56 ), radium ( z = 88 ). - anomalous properties of lithium : diagonal relationship | | this section may stray from the topic of the article into the topic of another article, diagonal relationship. ( march 2013 ) | 1. ) lithium is in group 1 and period 2. 2 ) magnesium is in 2 group and 3 period. 3. ) lithium resembles magnesium which is diagonally placed. \u00a4 cause of diagonal relationship - lithium and magnesium have similar ionic size and polarizing power hence they show diagonal relationship. \u00a4 similarities between lithium and magnesium - due to similar ionic size and polarizing power. ' li ' and ' mg ' shows similar properties. 1 ) both li and mg are hard metals. 2 ) licl and mgcl2 are deliquecent and crystallize as hydrates. licl. 2h2o and mgcl. 2h2o. 3 ) both li and mg combine with nitrogen to form nitrides. 4 ) hydroxides of both li and mg are weak bases. 5 ) carbonates of both li and mg decompose on heating. 6 ) hydrogen carbonates of both li and mg do not exist in solid states. anomalous behaviour of lithium lithium - the first", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6481181397195468, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.769295"} {"text": "both li and mg are weak bases. 5 ) carbonates of both li and mg decompose on heating. 6 ) hydrogen carbonates of both li and mg do not exist in solid states. anomalous behaviour of lithium lithium - the first element of group 1 - differs from the rest of this group in many respects. this anomalous behaviour of lithium is due to the following reasons : - small size of lithium atom and its ion. - higher polarization power of li + ( i. e. charge size ratio ) resulting in increased covalent character of its compounds which is responsible for their solubility in organic solvents - comparatively high ionisation enthalpy and low electropositive character of lithium as compared to other alkali metals - strong intermetallic bonding some of the properties in which lithium differs from other members of its group illustrating its anomalous behaviour are as follows : - lithium is harder than sodium and potassium which are so soft that they can be cut by a knife. - the melting and boiling points of lithium are comparatively high. - lithium forms monoxide with oxygen, other alkali form peroxide and superoxide. - lithium combines with nitrogen to form nitrides, while other alkali metals do not. - lithium chloride is deliquescent and crystallizes as a hydrate licl. 2h2o, whereas other alkali metal chlorides do not form hydrates. - hydroxide of alkali metals don ' t decompose but lioh decompose in li2o + h2o - lithium carbonate decompose on heating into li2o + co2 but rest of all decompose as moh + h2o + co2 - alkali nitrate make nitrites and o2 on heating but li2no3 decompose into li2o and gives brown colour gas no2 and o2 see also", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6056847022028083, "token_count": 385, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 1, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:15.771664"} {"text": "as we work with coalgebras, we \u2019 ll need a nice way to write out the comultiplication of an element. in the group algebra we \u2019 ve been using as an example, we just have, but not all elements are so cleanly sent to two copies of themselves. and other comltiplications in other coalgebras aren \u2019 t even defined so nicely on any basis. so we introduce the so - called \u201c sweedler notation \u201d. if you didn \u2019 t like the summation convention, you \u2019 re going to hate this. okay, first of all, we know that the comultiplication of an element is an element of the tensor square. thus it can be written as a finite sum now, this uses two whole new letters, and, which might be really awkward to come up with in practice. instead, let \u2019 s call them and, to denote the first and second factors of the comultiplication. we \u2019 ll also move the indices to superscripts, just to get them out of the way. the whole index - summing thing is a bit awkward, especially because the number of summands is different for each coalgebra element. let \u2019 s just say we \u2019 re adding up all the terms we need to for a given : then if we \u2019 re really pressed for space we can just write. since we don \u2019 t use a subscript in parentheses for anything else, we remember that this is implicitly a summation. let \u2019 s check out the counit laws in this notation. now they read. or, more expansively : similarly, the coassociativity condition now reads in the sweedler notation we \u2019 ll write both of these equal sums as or more simply as. as a bit more practice, let \u2019 s write out the condition that a linear map between coalgebras is a coalgebra morphism. the answer is that must satisfy notice here that there are implied summations here. we are not asserting that all the summands are equal, and definitely not that ( for instance ). sweedler notation hides a lot more than the summation convention ever did, but it \u2019 s still possible to expand it back out to a proper summation - heavy format when we need to.", "subdomain_id": "subdomain_quantum_field_theory", "similarity_score": 0.6243606000859615, "token_count": 476, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:17.176454"} {"text": "key : \" s : \" = show synset ( semantic ) relations, \" w : \" = show word ( lexical ) relations display options for sense : ( gloss ) \" an example sentence \" - s : ( n ) chewing gum, gum ( a preparation ( usually made of sweetened chicle ) for chewing ) - s : ( n ) gingiva, gum ( the tissue ( covered by mucous membrane ) of the jaws that surrounds the bases of the teeth ) - s : ( n ) gum ( any of various substances ( soluble in water ) that exude from certain plants ; they are gelatinous when moist but harden on drying ) - s : ( n ) glue, gum, mucilage ( cement consisting of a sticky substance that is used as an adhesive ) - s : ( n ) gumwood, gum ( wood or lumber from any of various gum trees especially the sweet gum ) - s : ( n ) gum tree, gum ( any of various trees of the genera eucalyptus or liquidambar or nyssa that are sources of gum ) - s : ( v ) gum ( cover, fill, fix or smear with or as if with gum ) \" if you gum the tape it is stronger \" - s : ( v ) mumble, gum ( grind with the gums ; chew without teeth and with great difficulty ) \" the old man had no teeth left and mumbled his food \" - s : ( v ) gum ( become sticky ) - s : ( v ) gum ( exude or form gum ) \" these trees gum in the spring \"", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6216557871831283, "token_count": 322, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:17.452426"} {"text": "this is the second dimension of color and is possibly the simplest to understand. it is, according to albert munsell ' s definition, \" the quality by which we distinguish a light color from a dark one. \" we noted that the first dimension did not tell us whether a color was light or dark. it told us that the color was green and not red, but we know that there may be light green and dark green. the function of value is to tell us how light or how dark a given color is. for this purpose we shall need a scale of value, which we may conceive as a vertical pole, or axis, to our circle of hues. black is at the lower end, representing total absence of light. white is at the top, representing pure light. between these are a number of divisions of gray, regularly graded between black and white. this gradation could also be infinite. since pure black is unattainable, we will call that 0 and begin our scale with the darkest gray as 1, numbering the steps up to 9, which is the lightest gray. pure white, which is also unattainable, we will call 10. in the practical use of the scale of value, therefore, we shall have but 9 steps and the middle one of these will be 5 - what is referred to as middle value. these steps of value, have been scientifically measured and registered by means of an instrument called a photometer. * in writing a color formula we express this dimension of value by a numeral, which denotes at what step upon the scale of value this color falls. this numeral is written above a line, as b 6 / for example, by which we mean that this particular blue, regardless of its other qualities, is as light or as dark as the 6th step upon the scale of value. a color such as is commonly called \" maroon \" is an example of a red which is low in value, because it is dark. what is called \" pink \" is a red which is high in value because it is light. now having familiarized ourselves with these two dimensions and understanding what qualities of a color they express, we may proceed to consider the third dimension. without this third dimension our description of any given color is incomplete. * this instrument is described in albert munsell ' s book, \" a color notation. \" munsell color co., boston, 1919, p. 38.", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6207921153739555, "token_count": 499, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:17.704830"} {"text": "the original question was : \u2026 true randomness on a quantum level has experimentally been shown to exist. my question is, does this quantum randomness ever / often / always bubble up to our readily observable world of newtonian physics to create truly random everyday events? physicist : hard to say. quick aside : the difference between quantum randomness, which is absolute, and classical randomness, which basically means \u201c very hard to predict \u201d, is covered a bit in this older post. in a nutshell, up until the science of quantum mechanics came along it was assumed that if you ( somehow ) knew everything about an object at one moment, you would be able to perfectly predict how it behaved the next. however, it turns out that even if you know absolutely everything about a radioactive atom, for example, it \u2019 s still impossible to accurately predict when it will decay. this is called \u201c fundamental \u201d, \u201c irreducible \u201d, or \u201c quantum \u201d randomness. back to the point : large scale effects can be thought of in terms of lots of small - scale effects being averaged together which usually ( and counter - intuitively ) leads to much more predictable ( classical ) results. this is the same idea that shows up when you flip lots of coins : the total number of heads is very predictably about half. generally speaking, any individual quantum event will be drowned out by the noise of all of the other quantum events around it, and the average is the only important thing. large scale events that rely on a small number of atoms and interactions are likely to have the same kind of randomness as \u201c legit \u201d quantum phenomena. for example, the meter on a geiger counter is an example of quantum randomness on a large - scale. nuclear decay is a quantum mechanically random process. normally, the effects of nuclear decay are washed out. for example, you \u2019 re hit, on average, by about one high energy particle per exposed square centimeter every second. ever notice? but a geiger counter detects every high energy particle that passes through its detector ( the wand on the right ) and notes the event by moving a needle ( which is huge by quantum standards ) and clicking. so, what geiger counters and other sensitive detectors do is \u201c exaggerate \u201d tiny events and bring their effects into the macro - scale. normally, large - scale events are fairly well determined. whether or not you go to lunch is probably not particularly random. if someone somehow got every possible piece of information about what everything in the nearby", "subdomain_id": "subdomain_quantum_mechanics", "similarity_score": 0.686957230277254, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:17.745335"} {"text": "events and bring their effects into the macro - scale. normally, large - scale events are fairly well determined. whether or not you go to lunch is probably not particularly random. if someone somehow got every possible piece of information about what everything in the nearby universe was doing, they \u2019 d be able to predict large - scale events, including your lunch schedule, with fair accuracy. however, if you determine whether or not to go to lunch based entirely on the results of a geiger counter reading, then your lunch outing is a genuine, fundamentally random event. this wouldn \u2019 t change the experience ; you won \u2019 t see different versions of yourself walking around, and you won \u2019 t end up \u201c spread thin \u201d across different versions of the universe. a quantum random number generator is essentially the same as an ordinary random number generator. that all said, there \u2019 s chaos inherent to most of the stuff that happens in the world ( tiny errors becoming bigger errors, becoming bigger errors, \u2026 ). however, there \u2019 s nothing particularly special about the original source of the errors being quantum mechanical. as far as prediction goes, randomness due to quantum mechanics and randomness due to a lack of perfect knowledge ( which is pretty hard to avoid ) are pretty much the same. this is a pretty subtle distinction. you can expect that, after a lot of time, the randomness of quantum processes will lead to worlds that are wildly different from each other because of the butterfly effect. but that \u2019 s pretty unsatisfying. it would be more interesting to be able to point at a large thing in the world and say \u201c that is dependent on just a couple of quantum events \u201d. the most dramatic example of exactly that is probably biological life. the earliest development of a creature is strongly influenced by the interactions of a relatively small number of chemical interactions. an atom in the wrong place in the flagella motor of a sperm can determine whether or not someone is born at all. more than that, the evolution of entire species can be changed by a single mistake in the replication of a strand of dna ( this is one mechanism for mutation ). on a more individual basis, it \u2019 s hard to say how much the process of thinking is affected by the actions of just a few atoms. the fact that you can lose a heck of a lot of brain cells without noticing implies that the activity of a handful of atoms probably isn \u2019 t too important when it comes to human behavior. that said ; maybe? by the way, it \u2019 s a little dangerous to tread this", "subdomain_id": "subdomain_quantum_mechanics", "similarity_score": 0.6472145043516604, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 1, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:17.746734"} {"text": "jumping droplets key to energy efficient products microscopic water droplets jumping from one surface to another could hold the key to a wide array of more energy efficient products \u2014 from large solar panels to compact laptop computers, say scientists. a team at duke university has, in fact, developed a new way of producing thermal diodes, devices which regulate heat to preferentially flow in a certain direction, effectively creating a thermal conductor in the forward direction and an insulator in the reverse direction. while thermal diodes can be made from solid materials, these solid - state diodes are not nearly as effective as \u201c phase - change \u201d thermal diodes that rely on vaporisation and condensation to transport heat, say the scientists. these phase - change diodes can transfer over a hundred times more heat in the forward direction compared to the reverse, but with major limitations \u2014 they are dependent on gravity or restricted by a tubular configuration. these limitations severely constrain the application of phase - change thermal diodes, for example, in mobile electronics which require orientation independence or solar panels which require a large surface area. the duke engineers believe they have figured out a way to solve these limitations to existing thermal diodes by exploiting self - propelled water droplets, which can jump from a superhydrophobic ( highly water - repellent ) surface to a superhydrophilic ( highly absorbent ) surface, but not the other way around.", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6177979926367659, "token_count": 286, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:17.933704"} {"text": "included here are more in depth explanations of some of the terms and processes in the nuclear fuel cycle. nuclear fuel is produced utilizing various elements and compounds in reactions that yied the product desired at the various stages. initially uranium is the prime constituent looked for in its natural setting during the exploration phase. the ore body, the rock, that holds the uranium also contains many other elements and compounds. while these remain undisturbed, very little of these components enter the surrounding environment. but once mining is initiated, all of the components are moved throughout the environment and left, in many cases, to contaminate the ground and water systems. while most of the uranium is taken from the mine location, almost all of the other components are left in piles of waste rock and tailings either at the mine or at the mill. below are the various components found in uranium ore bodies. full descriptions can be found on wikepedia. uranium - ( pronounced / j\u028a\u02c8re\u026ani\u0259m / ) is a silvery - gray metallic chemical element in the actinide series of the periodic table that has the symbol u and atomic number 92. it has 92 protons and 92 electrons, 6 of them valence electrons. it can have between 141 and 146 neutrons, with 146 ( u - 238 ) and 143 in its most common isotopes. uranium has the highest atomic weight of the naturally occurring elements. uranium is approximately 70 % denser than lead, but not as dense as gold or tungsten. it is weakly radioactive. it occurs naturally in low concentrations ( a few parts per million ) in soil, rock and water, and is commercially extracted from uranium - bearing minerals such as uraninite ( see uranium mining ). a person can be exposed to uranium ( or its radioactive daughters such as radon ) by inhaling dust in air, or by ingesting contaminated water and food. absorbed uranium tends to bioaccumulate and stay for many years in bone tissue because of uranium ' s affinity for phosphates. normal functioning of the kidney, brain, liver, heart, and numerous other systems can be affected by uranium exposure, because in addition to being weakly radioactive, uranium is a toxic metal. uranium is also a reproductive toxicant. in nature, uranium atoms exist as uranium - 238 ( 99. 284 % ), uranium - 235 ( 0. 711 % ), and a very small amount of uranium - 234 ( 0. 0058 % ). uranium decays slowly by emitting an alpha particle. the half", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6141434425281913, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:18.056461"} {"text": "be one of the heavy metals. lead has a bluish - white color when freshly cut, but tarnishes to a dull grayish color when exposed to air. it has a shiny chrome - silver luster when melted into a liquid. lead has the highest atomic number of all stable elements, although the next element, bismuth, has a half - life so long ( longer than the estimated age of the universe ) it can be considered stable. like mercury, another heavy metal, lead is a potent neurotoxin that accumulates in soft tissues and bone over time. lead is a poisonous metal that can damage nervous connections ( especially in young children ) and cause blood and brain disorders. to read a more in depth description please visit the wikipedia link : lead molybdenum - ( pronounced / m\u0259\u02c8l\u026abd\u0259n\u0259m /, from the greek word for the metal \" lead \" ), is a group 6 chemical element with the symbol mo and atomic number 42. it has the eighth - highest melting point of any element. it readily forms hard, stable carbides, and for this reason it is often used in high - strength steel alloys. molybdenum is found in trace amounts in plants and animals, although excess molybdenum can be toxic in some animals. the ability of molybdenum to withstand extreme temperatures without significantly expanding or softening makes it useful in applications that involve intense heat, including the manufacture of aircraft parts, electrical contacts, industrial motors, and filaments. molybdenum dusts and fumes, as can be generated by mining or metalworking, can be toxic, especially if ingested ( including dust trapped in the sinuses and later swallowed ). low levels of prolonged exposure can cause irritation to the eyes and skin. the direct inhalation or ingestion of molybdenum and its oxides should also be avoided. chronic exposure to 60 to 600 mg mo / m\u00b3 can cause symptoms including fatigue, headaches, and joint pains. to read a more in depth description please visit the wikipedia link : molybdenum vanadium - ( ipa : / v\u0259\u02c8ne\u026adi\u0259m / ) is the chemical element with the symbol v and atomic number 23. it is a soft, ductile, silver - grey metal. most vanadium is used as ferrovanadium as an additive to improve steels. all vanadium compounds should be considered to be toxic.", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6317675449010323, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 4, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:18.064163"} {"text": "v and atomic number 23. it is a soft, ductile, silver - grey metal. most vanadium is used as ferrovanadium as an additive to improve steels. all vanadium compounds should be considered to be toxic. the occupational safety and health administration ( osha ) has set an exposure limit of 0. 05 mg / m3 for vanadium pentoxide dust and 0. 1 mg / m3 for vanadium pentoxide fumes in workplace air for an 8 - hour workday, 40 - hour work week. the national institute for occupational safety and health ( niosh ) has recommended that 35 mg / m3 of vanadium be considered immediately dangerous to life and health. this is the exposure level of a chemical that is likely to cause permanent health problems or death. to read a more in depth description please visit the wikipedia link : vanadium in nuclear science, the decay chain refers to the radioactive decay of different discrete radioactive decay products as a chained series of transformations. most radioactive elements do not decay directly to a stable state, but rather undergo a series of decays until eventually a stable isotope is reached. decay stages are referred to by their relationship to previous or subsequent stages. a parent isotope is one that undergoes decay to form a daughter isotope. the daughter isotope may be stable or it may decay to form a daughter isotope of its own. the daughter of a daughter isotope is sometimes called a granddaughter isotope. the four most common modes of radioactive decay are : alpha decay, beta minus decay, beta plus decay ( considered as both positron emission and electron capture ), and isomeric transition. of these decay processes, alpha decay changes the atomic mass number ( a ) of the nucleus, and always decreases it by four. because of this, almost any decay will result in a nucleus whose atomic mass number has the same residue mod 4, dividing all nuclides into four classes. the members of any possible decay chain must be drawn entirely from one of these classes. all four chains also produce helium, from alpha particles. three main decay chains ( or families ) are observed in nature, commonly called the thorium series, the radium series ( not uranium series ), and the actinium series, representing three of these four classes, and ending in three different, stable isotopes of lead. the mass number of every isotope in these chains can be represented as a = 4n, a = 4n + 2, and a = 4n + 3, respectively. the long - lived starting", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6131147829776926, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 5, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:18.066073"} {"text": "everyone in the electrical industry, including the electrical apprentice, the journeyman, the master electrician, electrical contractor, electrical engineer, designer, the electrical inspector, et al., seem to use the phrase \u201c neutral conductor. \u201d however, until the 2008 national electrical code ( nec ), we did not actually have a definition of a neutral. in the process of determining the definition of a neutral for the 2008 nec, the nec technical committee task group on the definition of \u201c neutral conductor \u201d realized two definitions were required to adequately define this seemingly elusive component of the electrical system. the definition of a neutral conductor, as developed by the task group, was derived from the international electrotechnical commission definition of neutral conductor with some minor text changes to adapt to the nec style. this definition read, \u201c neutral conductor \u2014 the conductor connected to the neutral point of a system that is intended to carry current under normal conditions. \u201d the definition establishes that any conductor connected to a neutral point of an electrical system is intended to carry current under normal conditions. any electricians who find themselves connected to a neutral conductor carrying the imbalanced current of the circuit will certainly verify that the neutral is a current - carrying conductor. most electricians, myself included, also will admit that it is very difficult to \u201c get off \u201d the neutral conductor once connected to it since the current is on the load side of the circuit. most people either fall away, breaking the connection if on ground or floor level, or fall off the ladder when not working at grade level. we all count ourselves very lucky to have survived the neutral \u201c connection. \u201d whenever possible, work on the circuit in an electrically safe work condition. in other words, ensure the circuit has been locked off, and verify that the circuit is de - energized. upon analyzing the newly developed definition of a \u201c neutral, \u201d the task group then decided that a second definition was necessary to further explain the \u201c neutral point. \u201d the definition of neutral point was found in the ieee standard c57. 12. 80 - 2002 and read, \u201c the common point on a wye - connection in a polyphase system or midpoint on a single - phase, 3 - wire system, or midpoint of a single - phase portion of a 3 - phase delta system, or a midpoint of a 3 - wire, direct - current system. \u201d again, with some minor text changes to fit the nec format, this text was adopted into the 2008 nec. to make the two definitions as technically correct as possible, a", "subdomain_id": "subdomain_quantum_materials", "similarity_score": 0.6205166395730064, "token_count": 512, "source_dataset": "HuggingFaceFW/fineweb-edu", "source_id": "", "chunk_index": 0, "filtering_threshold": 0.6, "created_at": "2025-12-26T13:41:18.129720"}