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2021-07-01 | Abstract The yields of coal liquids (maltenes and asphaltenes) formed upon the heat treatment of three low-metamorphosed Kuzbass coals with different hydrogenation ability parameters in an atmosphere of hydrogen were compared. It was found that the H/C atomic ratios, the yields of volatile substances, the relative maximum rates of pyrolysis of coals in a range of 300–500°C, and the ratios between aliphatic and aromatic structures [( D 2920 + D 2860 )/ D 1600 ] in the test coals increased linearly with an increase in the yields of liquid products in the order Karakan long-flame coal < Itat brown coal < Barzas sapromixite. The best correlation ( R = 0.9792) was observed between the yields of liquid products and the [( D 2920 + D 2860 )/ D 1600 ] ratios. The thermal transformations of two types of Barzas sapromixites [a tile-like modification (“tile”) and its weathering product (gunny-like coal)] in different atmospheres (Н 2 and СО 2 ) were studied. It was found that a higher yield of coal liquids was observed upon the heat treatment of the Barzas sapromixites in an atmosphere of hydrogen, as compared with that upon their thermal conversion in an atmosphere of carbon dioxide. In the course of the heat treatment of the tile-like Barzas coal in an atmosphere of hydrogen, the yield of coal liquids (~37.7 wt %) was higher by a factor of >1.5 and the yield of gases (~10.3 wt %) was lower by a factor of >2 than those in similar experiments with the gunny-like coal. | Thermal Transformations of Low-Metamorphozed Kuzbass Coals in Different Atmospheres and Prediction of Coal Hydrogenation Ability in Direct Liquefaction Processes | 10.3103/S036152192104008X |
2021-07-01 | In this paper, a voltage mode all-pass filter design employing floating current sources (FCS) is proposed. The presented all-pass filter circuit contains two floating current sources, one grounded resistor and one floating capacitor. Furthermore, the PMOS transistors of the FCSs are replaced with dynamic threshold-voltage MOSFET (DTMOS) transistors. Due to the use of DTMOS transistors, power consumption and supply voltages of the filter circuit are reduced considerably, compared to the classical circuit. The gain and phase responses, input and output waves, the total harmonic distortion (THD) results, temperature performance, output noise voltage and Monte Carlo (MC) analyses of the all-pass filter are simulated. The simulation results of the proposed DTMOS based circuit are performed with the LTSPICE program using 0.18 μm TSMC CMOS process parameters. | DTMOS based low-voltage low-power all-pass filter | 10.1007/s10470-021-01878-z |
2021-07-01 | Abstract This work reports on the results of the studies of the material composition and physical properties of the basement rocks of the West Siberian Plate. It has been shown that the rocks contain bitumens of anthraxolite and kerite groups. We assume that the bitumens create the Late Paleozoic paleodeposit, transformed under the conditions of apocatagenesis. Impregnation with highly transformed organic matter leads to a significant decrease in electrical resistivity to values of 1–30 ohm m, which must be taken into consideration when interpreting the low-resistivity zones on the basis of log data. | Bitumens as a Cause of the Occurrence of the Low Electrical Resistivity Zones in the Basement Rocks of the West Siberian Plate | 10.3103/S0145875221040062 |
2021-07-01 | Abstract Based on literature and our own data, the effect of boron on the characteristics of all stages of metallurgical processes (from sintering, smelting of cast iron and ferroalloys, to steel production) and on the properties of the resulting slag and metal was studied. To intensify hardening of the pellets at the stage of liquid-phase sintering and to improve their metallurgical properties, it is sufficient to have 0.20–0.35% of boron oxide in them. According to laboratory studies, the presence of boron oxide in pellets increases their compressive strength by 1.5–1.7 times and hot strength by 3–4 times. While studying the mechanism and kinetics of sulfur removal, it was shown that the presence of boric anhydride significantly intensifies processes of ±pellets desulfurization. Their intensive progress goes to the zones of lower temperatures of 1050–1100°C. To increase the sinter strength characteristics, it is possible to add B 2 O 3 to the charge. The introduction of 0.44% of B 2 O 3 does not affect the sinter abrasion. The content of fines (0–5 mm) in comparison with the base sample is reduced by 1.5 times. The use of boron pellets in blast-furnace smelting makes it possible to increase the basicity of the final slag from 1.10 to 1.16. In this regard, the sulfur distribution coefficient increases from 48 to 74. The sulfur content in cast iron decreases by 0.005%. The possibility of using boron and its compounds to improve the technical and economic indicators of production and pellet quality, sinter and cast iron is shown on the base of the presented theoretical, laboratory-experimental and industrial data. | Prospects for Using Boron in Metallurgy. Report 1 | 10.3103/S0967091221070111 |
2021-07-01 | Abstract To explore a new formulation system of diamond bit matrix, three kinds of Fe-based pre-alloyed powder with low liquid phase content were utilized for the matrix fabrication of impregnated diamond bit (IDB). To this end, the D-optimal mixture design method was employed for the design of the experiment scheme which contained 16 groups of samples. The samples were fabricated under the same hot pressing sintering conditions, then tests on hardness, bending strength, and relative density were conducted. The results were analyzed by regression analysis, and so were the interrelations and interactions of formula components on matrix properties. Meanwhile, the fracture surface of samples after the bending strength test was observed by SEM. It was found that FAM1020 and FAM2120 have a positive effect on the bending strength of metal matrix composite. Besides, FAM2120 has a positive effect on the hardness of the matrix, but a negative effect on the bending strength of the diamond matrix composite. The interaction among the three powders can improve the performance of the matrix. According to the result, the Fe-based pre-alloyed bit matrix with low liquid phase content can meet the requirements of the diamond bit matrix. Based on this exploration experiment, an optimal formulation is concluded as 50 wt % X 1 , 30 wt % X 2 , 20 wt % X 3 . | D-Optimal Mixture Design of Fe-Based Pre-Alloyed Diamond Bit Matrix with Low Liquid Phase Content | 10.3103/S1063457621040080 |
2021-07-01 | Cold pilgering process is a seamless tube forming technology, in which the metal is subjected to a series of small incremental deformations. It has been extensively applied for the manufacturing of cladding tube in nuclear reactors, due to high dimensional accuracy and favorable texture evolution. Notwithstanding, the pilgered tubes showed a kind of shear cracks similar to those obtained during low-cycle shear fatigue experiments. To confirm it, a novel low-cycle shear fatigue experiment was designed, in which the shear stress amplitude was obtained from a tracking point in the inner surface of the pilgered tube through finite element model (FEM). Additionally, a theoretical model was established based on the experimental results to predict fatigue life during the cold pilgering process. Through this model, the effects of Q value, side relief, and friction coefficient on the safety factor during cold pilgering were investigated. The results showed that with the increase of Q value, and the decrease of the difference between the friction coefficients of the inner and outer surfaces, the safety of cold pilgering tube could be improved by decreasing the tendency of shear cracks. | Shear cracks of Zircaloy tube during cold pilgering: experimental investigation and numerical modeling | 10.1007/s12289-019-01534-y |
2021-07-01 | New finite strain elastoplastic $$J_2$$ J 2 -flow equations with no reference to the yield condition are proposed for the purpose of simultaneously simulating low-to-ultrahigh cycle failure effects of metals. As inherent response features of such new equations, the entire responses up to eventual failure under cyclic and non-cyclic loadings of constant and variable amplitudes are automatically predicted, in a direct sense without involving any additional damage-like variables and any ad hoc failure criteria. The thermodynamic consistency is ensured by demonstrating that the intrinsic dissipation is identically non-negative. Furthermore, a high-efficiency algorithm for integrating the elastoplastic rate equations is established toward bypassing very time-consuming numerical procedures in treating cyclic responses with high and even ultrahigh cycle number. With numerical examples, model predictions are shown to be in good agreement with fatigue failure data for low, high and very high cycle numbers, and the new algorithm is shown to be much faster and far more efficient than usual integration procedures. | High and low cycle fatigue failure effects of metals predicted automatically from innovative elastoplastic equations with high-efficiency algorithms | 10.1007/s00161-020-00945-6 |
2021-07-01 | Multiple displacement amplification (MDA) is a popular single-cell whole-genome amplification (WGA) technique that can greatly improve the amplification efficiency of single-cell genomes. However, there is an inherent problem that cannot be completely solved, that is, the amplification bias. We here propose an improved MDA method based on low melting agarose gel, named gelMDA. Firstly, the agarose gel and solution were characterized with SEM and fluorescent reagent. Then, we used gelMDA for cDNA amplification in library preparation of RNA-seq, and conventional MDA was used as a comparison. The sensitivity, efficiency of gelMDA, and amplification bias were evaluated with fluorescence curve, product yield, and the sequencing results. Finally, gelMDA was used for single-cell transcriptome sequencing. The results showed that the sensitivity and product yield of gelMDA were significantly higher than those of conventional MDA. A lower coefficient of variation (CV) and a higher reproducibility were obtained from gelMDA sequencing results. A region of 30 μm in diameter was amplified from the tissue sections and successfully sequenced. In conclusion, gelMDA obtained higher amplification efficiency and lower amplification bias in the present study. It suggested the great potential in single-cell RNA amplification and sequencing. Graphical abstract | Low bias multiple displacement amplification with confinement effect based on agarose gel | 10.1007/s00216-021-03415-3 |
2021-07-01 | Abstract A study is performed of mixtures of ultra-high-molecular-weight high-density polyethylene (UHMWHDPE; T m = 141°C; enthalpy of fusion, 180 J g −1 ) with 90 wt % low molecular weight component (copper complex of phthalocyanine, anthracene, succinic acid, and spiropyran) in the presence of acid–base indicators (anthraquinone, phenolphthalein, phenol red, bromocresol purple, Congo red, methyl orange, and thymol blue), organic acids (succinic, fumaric, and aspartic), melamine, and cyanuric acid. The mixtures are subjected to plastic deformation at 1 GPa on an anvil-type high pressure apparatus and are analyzed with a DSC. Enthalpies of melting are determined for the polymer in the deformed mixtures (from 135 to 763 J g −1 ). It is found that the enthalpy of fusion of UHMWHDPE in mixtures with organic acids grows along with the strength of the acid. The enthalpy of melting of the polymer is no more than 210 J g −1 in mixtures with alkaline indicators, and is 664–763 J g −1 in mixtures with acids. Endothermic peaks of small crystallite melting and the exothermic peaks of cold crystallization are observed on the thermograms of the deformed mixtures at temperatures T m below those of the polymer. It is shown that the enthalpies of crystallization of the polymer in the deformed mixtures from melts are almost identical to those of the initial UHMWHDPE. | Melting and Crystallization of High-Density Polyethylene Mixed with Organic Acids and Acid–Base Indicators after Plastic Deformation at High Pressures | 10.1134/S0036024421070311 |
2021-07-01 | All-perovskite tandem solar cells (TSCs) show great potential for achieving efficiencies beyond the Shockley–Queisser limit owing to their excellent photovoltaic properties and cost effectiveness. In this review, the current status of all-perovskite TSCs as well as recent research progress are introduced with a focus on three main strategies: optimization of the interconnecting layer (ICL), suppression of tin oxidation in low-bandgap perovskites, and prevention of halide segregation in wide-bandgap perovskites. The development of triple-junction all-perovskite devices and remaining issues facing all-perovskite TSCs are also discussed. | Monolithic all-perovskite tandem solar cells: recent progress and challenges | 10.1007/s43207-021-00117-5 |
2021-07-01 | The role of N 2 in the upper atmosphere on the atomic oxygen (AO)-induced erosion of polyimide in low Earth orbit (LEO) and sub-LEO is investigated through ground-based experiments and flight data. The experiment is performed by adding an Ar beam at the same collision energy as an undecomposed O 2 component in the AO beam formed by laser detonation to simulate the physical effect of simultaneous N 2 collision in sub-LEO. The Ar beam is added by the dual-pulsed supersonic valve-equipped laser-detonation system developed at Kobe University. The experimental results indicate that the erosion of polyimide in the laser-detonation system is promoted by the presence of O 2 and Ar in the beam, corresponding to N 2 in the sub-LEO. On-ground experimental results are compared with in-orbit AO measurements. Previous space shuttle, international space station-based exposure experiments, as well as the world’s first real-time sub-LEO material erosion data aboard a super low altitude test satellite (SLATS) orbiting at an altitude of 216.8 km are presented. The SLATS data suggests the presence of an acceleration effect by N 2 collision on AO-induced polyimide erosion, as predicted by ground-based experiments. | Effect of simultaneous N2 collisions on atomic oxygen-induced polyimide erosion in sub-low Earth orbit: comparison of laboratory and SLATS data | 10.1007/s12567-021-00358-4 |
2021-07-01 | Comprehensive studies of tubing made of 36CrMn2Si and 38CrMn steels have shown that 38CrMn steel has better corrosion resistance compared to 36CrMn2Si steel. А reduction in steel silicon content leads to an increase in corrosion resistance. Increased contamination with complex nonmetallic inclusions of unfavorable composition has an unfavorable effect on corrosion resistance, as well as presence of chemical inhomogeneity in the form of banding. | Influence of Chemical Composition and Microstructure Parameters of Tubing Steels on their Corrosion Resistance | 10.1007/s11015-021-01157-2 |
2021-07-01 | Abstract The three-phase structure of the solid fermentation substrates is composed by the solid, liquid and gas phases, adjusting the ratio of the three-phase structure has proven to be a strategy that can better serve the growth of microorganisms. In this study, the effect of the three-phase structure of the cultivated substrate on the growth of Lentinula edodes was evaluated. Our results showed that the liquid phase was most impacted by the particle size and moisture content among the three-phase. Further analysis of the three-phase structure index (TPSI) showed that the highest efficiency of L. edodes growth was achieved at TPSI value of 23.3, and the liquid phase was the most affected variable on the TPSI of cultivated substrates among the three phases. Further, to determine the optimal water environment for L. edodes in the substrates, three types of water containing four proton components in the cultivation substrate were identified based on distributed exponential curve fitting of transverse relaxation ( T 2 ), namely, bound water T 2b , free water T 21a and T 21b , and bulk water T 22 . L. edodes exhibited the best growth efficiency on elm (59% moisture content), peanut shell (52% moisture content) and apricot (56% moisture content) substrates, all of which were filled with free water and without bulk water, respectively. The same conclusion was also obtained in the mixed material cultivation substrate. In overview, L. edodes had the best growth efficiency in substrates filled with free water and not containing bulk water, which enabled proton analysis based on LF-NMR spectroscopy to provide new insights into the moisture content of wood-rot fungal cultivated substrates. Graphic abstract | Three-phase structure analysis of sawdust cultivation substrates and rapid detection of the optimal water environment for Lentinula edodes growth based on LF-NMR | 10.1007/s10570-021-03987-4 |
2021-07-01 | Abstract The effect of complex physicochemical treatment combining low-frequency acoustic action and the use of depressor additives on the composition and viscosity properties of oil sludge was studied. After the complex action, the viscosity of the treated sediments additionally decreased by a factor of 1.5–2, and the thixotropic recovery of properties increased to 72 h. The minimum values of the viscosity of the mixtures of oil sludge with oil correspond to a maximum decrease in the concentration of benzene and alcohol–benzene resin components and an increase in the amount of the oil fraction. | Physicochemical Treatment of Oil Sediments in Oil Sludge Utilization | 10.3103/S0361521921040042 |
2021-07-01 | Abstract A methanol conversion catalyst based on natural aluminosilicate nanotubes and H–ZSM-5 zeolite was synthesized. Its textural, structural, and acid properties were studied by low-temperature nitrogen adsorption–desorption, transmission electron microscopy, X-ray diffraction analysis, and temperature-programmed ammonia desorption. The influence exerted on the methanol conversion and product distribution by the reaction temperature (380–460°С), pressure (0.1–0.5 MPa), and feed space velocity (0.5–1 h –1 ) was studied. The catalyst based on halloysite aluminosilicate nanotubes showed high selectivity in formation of both lower olefins and aromatic hydrocarbons. | Micro-Mesoporous Catalyst Based on Natural Aluminosilicate Nanotubes and ZSM-5 Zeolite for Methanol Conversion to Hydrocarbons | 10.1134/S0965544121070082 |
2021-07-01 | Flow boiling experiments in microchannels under low mass fluxes have rarely been reported in the literature. In this study, flow boiling critical heat flux (CHF) for a parallel straight copper microchannel heat sink with 41 channels and hydraulic diameter of 420 µm (width: 300 µm; height: 700 µm) is reported under low mass fluxes(< 100 kg/m 2 s). The flow patterns reveal that the inertial force will be too low to flush the bubble downstream. The heat transfer coefficient was observed to decrease with an increase in the heat flux or vapor quality, which pointed toward convective boiling dominancy inside the channels. When approaching the CHF, the vapor flowed back to the heat sink’s inlet plenum, resulting in a flow blockage, which is the main factor for the CHF occurrence. | Experimental investigation on critical heat flux measurement in parallel microchannel heat sink at low mass fluxes | 10.1007/s12206-021-0641-x |
2021-07-01 | Intentional addition of cheaper oils into olive oil (OL) for economic motivation has been becoming particularly attractive due to the favorable flavor and healthy characteristics of OL, but it is very challenging to identify such adulteration because of the compositional similarity between the oils. In this study, low-field nuclear magnetic resonance (LF-NMR) in combination with multivariate statistical analysis was used to identify the adulterated olive oil with different rations of soybean oil (SO) or corn oil (CO). Significant differences in multi-component relaxation time (T 21 and T 22 ) and peak area proportions (S 21 and S 22 ) were detected between pure and adulterated OL. As the adulteration ratio increased, S 21 and S 22 changed linearly, while T 21 and T 22 only changed slightly. The detection by gas chromatography suggested that T 21 and T 22 values might be influenced by triacylglycerol components, and the changes of S 21 and S 22 were attributed to the varied mono-/polyunsaturated fatty acids. In the relaxation time-based pattern recognition models, the authentic OL could be correctly identified from the adulterated ones with at least 20% of SO or CO by principal component analysis (PCA) or partial least squares discriminant analysis (PLS-DA). The multi-blended oil could be 100% classified by orthogonal partial least squares discriminant analysis (OPLS-DA) and 98.8% classified by principal component analysis followed by linear discriminant analysis (PCA-LDA) when the adulteration ratio was above 30%, demonstrating a promising technique of LF-NMR combined with pattern recognition in rapid screening of the edible oils. | Rapid Detection of Adulteration in Extra Virgin Olive Oil by Low-Field Nuclear Magnetic Resonance Combined with Pattern Recognition | 10.1007/s12161-021-01973-x |
2021-07-01 | Abstract — The study presents data on the biology of the marginal population of burbot Lota lota from the lower reaches of the Volga. Individuals aged from 3 to 7 years were recorded in the catches; a relatively short age range is due to mass die-offs of burbot in hot years. Spawning continues from mid-January to mid-February; the migration of larvae takes place until April–early May. The diet is dominated by the Ponto-Caspian kilka Clupeonella cultriventris and gobies (Gobiidae); among the latter, the most important are the round goby Neogobius melanostomus , the Caspian bighead Ponticola gorlap , and the monkey goby N. fluviatilis . At present, the southern populations of burbot of the Saratov reservoir and the lower reaches of the Volga are characterized by the highest growth rates in water bodies of Northern and Eastern Europe. This is primarily due to the high abundance and availability of prey that mostly represent fish species, which have expanded their presence in the Volga basin under conditions of regulated runoff. | Features of Burbor Lota lota (Gadidae) Biology in the Lower Volga | 10.1134/S0032945221040019 |
2021-07-01 | Purpose The analysis of n -alkanes in palaeoenvironmental studies of peatlands is mainly limited to ombrogenous peatlands which are a rare feature in the environment. Using n -alkane and plant macrofossil analysis, we have tracked changes in the environment in the valley of a large Central European river. We tested the possibilities for applying such studies to low-moor bogs which are the most commonly occurring type of bog in the world. Materials and methods Representative peat samples were taken from two profiles in a peatland located in the Vistula Valley (southern Poland), and they were analysed for the occurrence and distribution of biomarkers. The distribution of n -alkanes was determined using gas chromatography-mass spectrometry (GC–MS). The botanical composition of the samples was determined by analysis of plant macrofossil remains, and the degree of peat decomposition was also determined. Results and discussion Samples of low-moor peat were characterised by a prevalence of medium- and long-chain n -alkane homologues, which is typical for higher plants. The variable values of the CPI, CPI (25–31) , and the C 23 /C 25 ratio have provided information on the stages of formation of the Zapadź bog. The source of n -alkane differentiation is vegetation change related to palaeohydrological dynamics and palaeoenvironmental conditions within the peatland. Conclusions We have shown that analysis of n -alkanes can be successfully used in low-moor bogs as a complement to palaeobotanical and palaeozoological methods. The bringing together of these types of research enables changes in the ecosystems of large river valleys to be tracked. | Impacts of vegetation and palaeohydrological changes on the n-alkane composition of a Holocene peat sequence from the Upper Vistula Valley (southern Poland) | 10.1007/s11368-021-02981-4 |
2021-07-01 | The objective of this study was to determine the role of spring catchment water storage on the evolution of low flows in central European mountainous catchments. The study analysed 58 catchments for which catchment storage, represented by snow, soil water and groundwater storages, was determined by the HBV hydrological model over a 35-year period. The spring catchment storage was related to several streamflow indices describing low flow periods using the mutual information criterion. The mean runoff in the summer and autumn periods was mostly related to rainfall sums from the respective season. The median relative contribution of rainfall to the total mutual information value was 48.4% in summer, and 44.2% in autumn period, respectively. The relative contribution of soil water and groundwater storages was approximately 25% for each of the components. In contrast, the minimum runoff, its duration and deficit runoff volume, were equally related to both catchment storage and seasonal rainfall, especially in the autumn period. | Catchment Storage and its Influence on Summer Low Flows in Central European Mountainous Catchments | 10.1007/s11269-021-02871-x |
2021-07-01 | Abstract A complex for processing liquid radioactive waste from Mayak chemical metallurgical production plant has been designed, constructed, and put in operation. Pilot trials were performed to test the technology for processing liquid low-level radioactive waste using cross-flow ultrafiltration. The method was found to be efficient. A total of 126 000 m 3 of solutions were processed during the trials. The decontamination factor for alpha-emitting radionuclides was up to 10 3 . The filtration modules allow concentration of liquid radioactive waste to 1/300 of its initial volume without preliminary preparation and introduction of additional reagents. The organic components that appear in the processed solutions were found to adversely affect the operation of ultrafiltration units. | Processing of Liquid Low-Level Radioactive Waste Using Cross-Flow Ultrafiltration at Mayak Production Plant | 10.1134/S0040579521040138 |
2021-07-01 | Abstract The species composition of free-living planktonic ciliates and their distribution in the riverbed of the Middle and Lower Volga reservoirs during the end of the hydrological spring of 2016 and low water period of 2017 have been studied. The tendency of decreasing species diversity of ciliates downstream the cascade of the Volga reservoirs is shown and knowledge of the distribution of some rare species and the distribution of the main groups of structure-forming species from the orders Tintinnida and Choreotrichida along the Volga cascade has been broadened. The abundance of ciliates in the area from the dam of the Rybinsk hydroelectric power station to the city of Astrakhan varies from 20 to 4785 thousand cells/m 3 and the biomass varies from 0.1 to 254 mg/m 3 . The highest species diversity and quantitative and productive characteristics of the ciliate communities in the Gorky and Cheboksary reservoirs, as well as in the unregulated part of the Lower Volga, are due to their traditionally higher trophic level. Factors determining seasonal and interannual differences in the distribution of ciliates in reservoirs of the Volga River are discussed. | Structure and Spatial Distribution of Planktonic Ciliates from the Middle and Lower Volga Reservoirs | 10.1134/S1995082921030044 |
2021-07-01 | Since the shale matrix has a very low permeability, the flow in the matrix is often transient flow. Hence, conventional reservoir simulators often do not accurately estimate the mass exchange between matrix and fractures. To evaluate the effect of water injection on oil recovery realistically, reservoir simulators need to incorporate the mass transport in the reservoir at different scales. These issues have motivated us to evaluate the contribution of water injection on oil recovery in liquid-rich unconventional reservoirs accounting the effects of salinity, fluid type, shale swelling, and wettability alteration. In this research, a new mass transport model is used to compute the mass transfer mass exchange between the rock matrix and the fractures. A geomechanical model is also used to account for the effect of fluid–rock interaction on the permeability and porosity. The coupled model is solved for every matrix block within the reservoir-scale model to evaluate the overall effect of salt concentration, shale swelling, and wettability alteration on the mass exchange between the fractures and the shale matrix. The reservoir-scale simulation helps to determine the phase pressure, saturation, solute concentration, and liquid production. A computer code was developed to solve the transport and geomechanical equations simultaneously, and the code is validated with the benchmark problems as shown in the Appendix. The results show that osmosis significantly contributes to the recovery of oil from very low permeability shale matrix over a long time period. Shale matrix swelling also significantly reduces the permeability of the shale matrix and fractures, reducing overall oil recovery. Therefore, water injection is not recommended for formations with swelling potential. The modified-zipper pattern is recommended for enhanced oil recovery operations. The simulation results also suggested that oil recovery can be improved by increasing the density of hydraulic fractures. | Evaluation of Low Salinity Water Injection Improved Oil Recovery in Liquid-Rich Unconventional Reservoirs | 10.1007/s00603-021-02444-9 |
2021-07-01 | This paper presents a power-efficient successive-approximation register (SAR) analog-to-digital converter (ADC) with fast response reference buffer (RV-buffer). Several techniques are applied in the system design to improve the performance of the SAR ADC. A novel timing-redistribution SAR logic is proposed to balance the difference between required settling time for the most significant bit and the least significant bits (LSBs) in the digital-to-analog capacitor array, which reduces the incomplete settling error and releases the requirements on the RV-buffer to achieve lower power dissipation. The SAR ADC is fabricated in 40-nm CMOS technology occupying 0.13 mm $$^{2}$$ 2 area. At 1.1 V supply voltage and 80 MHz sampling frequency, the ADC achieves 50.7 dB SNDR, 69.5 dBc SFDR with a 1 MHz input at −8 dBFS. The total power consumption of the ADC is 2.99 mW, including the reference buffer power consumption of 2 mW. The Schreier FoM is 164.1 dB. | A Power-Efficient SAR ADC with Optimized Timing-Redistribution Asynchronous SAR Logic in 40-nm CMOS | 10.1007/s00034-020-01643-z |
2021-07-01 | 4-chlorophenol (4-CP) is recognized as a highly toxic organic which can cause damage effects on human life and the aquatic environment. Since conventional wastewater techniques were unable to remove non-biodegradable chlorophenols, advanced oxidation process was investigated to achieve this goal. Amongst them, non-thermal plasma was recently proposed as an alternative and promising technique. However, the energy efficiency of most non-thermal plasma technique is very low as well as the input energy is dissipated in many forms such as heat, UV radiation, electromagnetic waves, etc., that are not totally involved in the pollutant degradation. In this work, quantitative analyses of UV radiation and H 2 O 2 in a moist air gliding arc plasma (glidarc) were performed using potassium ferrioxalate actinometry and peroxytitanyl complex method, respectively. The role of UV light emitted in gliding arc plasma was elucidated by performing parallel experiments: H 2 O 2 , glidarc alone, glidarc + H 2 O 2 , glidarc + H 2 O 2 + Fe 3+ (plasma-Photo-Fenton). The results show that the incorporation of Fenton reagents in 4-CP solution exposed to the plasma enhanced the yields of chemical active species, which were available for efficient removal and mineralization of 4-CP. Graphic Abstract | Effect of Gliding Arc Plasma-Induced UV Light During the Photo-Fenton Oxidation of 4-Chlorophenol in Aqueous Solution | 10.1007/s11090-021-10171-w |
2021-07-01 | Purpose In order to increase the efficiency of the low-power holmium laser enucleation of the prostate (LP-HoLEP), and introduce it as a standard surgery for BPH, we described a modified ‘seven-step two-lobe’ HoLEP (ST HoLEP) technique applying 60-W device in a stepwise manner. Methods From July 2016 to August 2019, 120 patients who received LP-HoLEP at our hospital because of urinary tract symptoms caused by BPH were included in the study. The patients were assigned into two groups, 60 consecutive patients received modified ST HoLEP compared with another preexisting 60 consecutive patients who received the conventional three-lobe HoLEP (T HoLEP) before the technical modification. The clinical parameters, including patient characteristics, perioperative data, as well as voiding outcomes, and complications were evaluated after at least 3-month follow-up. Results The median enucleation efficiency of the ST HoLEP was 0.72 gm/min, which was significantly higher than 0.62 gm/min of the T HoLEP. Despite the preoperative IPSS was slightly higher in T HoLEP group, the other preoperative and perioperative data showed no statistical difference between the two groups. After ST HoLEP procedure, the urinary incontinence rate was continually improved at 1-week, 1-month, and 3-month follow-up which were 13.3%, 6.7%, and 1.7%, respectively. There was no significant difference in postoperative voiding outcomes and urinary continence results in 3-month follow-up. Conclusion The ST HoLEP technique was proved to increase the efficiency which was benefit from minimizing the surgical incision, facilitating the single surgical plane identification and maintenance during the whole enucleation procedure. | ‘Seven-step two-lobe’ HoLEP: a modification to gain efficiency of the enucleation applying relatively low-power holmium laser devices | 10.1007/s00345-020-03470-y |
2021-07-01 | Sustainable development of a community needs to be balanced in all dimensions. Global warming and climate change from human emissions can affect the development of communities including highland communities in Chiang Rai, Thailand in terms of human life, growth and yield of plants and animals. This research presents low-carbon tourism for the sustainable development of the rural highland community in Chiang Rai, Thailand by integrating economic, social and environmental objectives in community development for sustainability. This research is carried out through funding of a royal project and is based on mixed research methodology incorporating both qualitative and quantitative data analysis techniques in different stages including, ethnographic delphi future research, in-depth interview and observation. The study evaluates the community development levels standard and indicators for enhancing the community's economic development such as low carbon tourism development through analyzing the available resources and the Royal Project initiatives through education, meeting and discussion. The result shows its impact on four dimensions of development as 1. environmentally friendly agriculture; 2. forest restoration and conservation; 3. community health management; and 4. community strength to support change, to develop into sustainable low carbon highland communities. The results of this research can be used as a guideline for a sustainable low-carbon community development and also to evaluate criteria, indicators, as well as developmental steps for preparing and evaluating community development levels for certification of community development standards into low-carbon sustainable areas. | Toward a low-carbon tourism for sustainable development: a study based on a royal project for highland community development in Chiang Rai, Thailand | 10.1007/s10668-020-01083-4 |
2021-07-01 | The excitations of nonlinear magnetosonic lump waves induced by orbiting charged space debris particles in the Low Earth Orbital (LEO) plasma region are investigated in the presence of the ambient magnetic field. These nonlinear waves are found to be governed by the forced Kadomtsev–Petviashvili-type model equation, where the forcing term signifies the source current generated by different possible motions of charged space debris particles in the LEO plasma region. Different analytic lump wave solutions that are stable for both slow and fast magnetosonic waves in the presence of charged space debris objects are found for the first time. The dynamics of exact pinned accelerated magnetosonic lump waves is explored in detail. Approximate magnetosonic lump wave solutions with time-dependent amplitudes and velocities are analysed through perturbation methods for different types of localized space debris functions, yielding approximate pinned accelerated magnetosonic lump wave solutions. These new results may pave new directions in this field of research. | Accelerated magnetosonic lump wave solutions by orbiting charged space debris | 10.1007/s11071-021-06594-x |
2021-07-01 | Enterococcus faecalis ( E. faecalis ) is an indigenous intestinal bacterium and has potential to be applied as probiotic supplement. Low pH is one of the main stresses that E. faecalis has to deal with to colonize in the gastrointestinal tract. Previous study indicated low concentration of flavonoids may enhance the tolerance of probiotic to environmental stress. In the present research, transcriptome analysis was employed to investigate the influence of Cyclocarya paliurus flavonoids (CPF) on E. faecalis exposed to low pH environment. The results revealed that under the stress of low pH, genes related to cell wall and membrane, transmembrane transport, metabolism process, energy production, and conversion stress proteins were significantly differentially expressed. And certain undesired changes of which (such as genes for MFS transporter were downregulated) could be partially mitigated by CPF intervention, indicating their capacity to improve the low pH tolerance of E. faecalis . Results from this study deepened our understanding of the beneficial role of CPF on the probiotic in the gastrointestinal environment. | Transcriptome analysis of Cyclocarya paliurus flavonoids regulation of differently expressed genes in Enterococcus faecalis under low pH stress | 10.1007/s00203-021-02215-8 |
2021-07-01 | A gap exists between clinical practice guidelines and real-world practice. We aim to investigate hospital admissions among patients presenting to emergency departments of 11 hospitals with venous thromboembolism (VTE). Eligible patients’ first emergency department VTE visit were retrospectively collected between 2013 and 2018 from electronic medical records (EMR). Patients were categorized at low risk of VTE complications if they were diagnosed with deep vein thrombosis (DVT) of the leg or if they were diagnosed with pulmonary embolism (PE) and had a PE score index < 85. Multivariable logistic regression models were constructed to measure the adjusted odds ratios (OR) and 95% confidence intervals (CI) of hospital admissions before and after clinical practice guidelines were updated to recommend outpatient management of DVT and PE with low risk of complications. A total of 13,677 patients were included in the analysis, of which 55% were diagnosed with DVT. Mean age was 65 ± 17 years, 54% were females, and 62% were Caucasian. Overall, 9281 patients were categorized at low risk VTE complications, of whom 77% were admitted for in-hospital management. The rate of in-hospital management declined from 81% in 2013 to 73% in 2018. Patients visiting emergency departments between 2016 and 2018 (post-guidelines) were equally likely to be admitted compared to patients visiting the emergency departments between 2013 and 2015 (pre-guidelines; OR = 0.99; 95% CI: 0.88, 1.11). Results from this real-world study indicate that most low-risk VTE patients are admitted for in-hospital management, despite recommendations in clinical practice guidelines. | Outpatient management of patients presenting with venous thromboembolism: Retrospective cohort study at 11 community hospitals | 10.1007/s11239-020-02328-9 |
2021-07-01 | A long-duration laboratory study spanning more than 6 months was conducted to evaluate the effect of operating mode on the performance of sand filters for greywater treatment. Performance of saturated and unsaturated filters operated in continuous or intermittent mode was evaluated using settled real greywater. Effects of pause period and higher loading rate on their performance were also evaluated. Furthermore, the effect of the depth of the filter medium on the performance of the filters was also assessed. The saturated filters operated continuously or intermittently performed significantly better than the respective unsaturated filters. Saturated continuous (SC) and unsaturated intermittent (UI) filters were the best and worst performers amongst the different filters. SC filter removed on an average 98% turbidity, 76% BOD, 88% COD, 84% ammonia-N (NH 4 -N) and 95% phosphate (PO 4 -P). Up to 99.68% (2.40 log) removal of faecal coliforms was also achieved by this filter. SC filter showed stable and reliable performance as its effluent quality was insensitive to fluctuations in influent quality. The pause period significantly affected the removal of some of the parameters. Doubling the hydraulic loading rate significantly affected the performance of continuous filters. Though most of the pollutant removal occurred in the top 10 cm in all the filters, a depth of 50 cm was found optimum for the removal of different pollutants. Whilst all the filters produced effluent conforming to different reuse standards except microbial standards, saturated continuous filter (SC) could also meet the faecal coliform standards towards the end of the filter operation. | Effect of operating mode on the performance of sand filters treating greywater | 10.1007/s11356-021-13413-8 |
2021-07-01 | Substantial pieces of evidence support the potential of exogenous toxins in disrupting neuroimmune homeostasis. It appears that mycotoxins are one of the noticeable sources of naturally occurring substances dysregulating the immune system, which involves the physiology of many organs, such as the central nervous system (CNS). The induction of inflammatory responses in microglial cells and astrocytes, the CNS resident cells with immunological characteristics, could interrupt the hemostasis upon even with low-level exposure to mycotoxins. The inevitable widespread occurrence of a low level of mycotoxins in foods and feed is likely increasing worldwide, predisposing individuals to potential neuroimmunological dysregulations. This paper reviews the current understanding of mycotoxins’ neuro-immunotoxic features under low-dose exposure and the possible ways for detoxification and clearance as a perspective. | Neuroimmune disruptions from naturally occurring levels of mycotoxins | 10.1007/s11356-021-14146-4 |
2021-07-01 | Hintergrund Eine verminderte antithrombozytäre Prophylaxe („Low-Response [LR]“/„high on-treatment platelet reactivity [HPR]“) mit Acetylsalicylsäure (ASS) ist mit einem erhöhten Risiko für thrombembolische Ereignisse assoziiert. Die Prävalenz einer Low-Response ist mit ca. 20 % häufig und ein Therapieregime wurde bisher noch nicht etabliert. Das Ziel dieser prospektiven Studie war es, die Effektivität eines Therapieschemas zur Therapieanpassung bei detektierter LR/HPR bei gefäßchirurgischen Patienten zu evaluieren. Methodik Insgesamt wurden 36 gefäßchirurgischen Patienten mit einer antithrombozytären Dauermedikation mit ASS 100 mg/Tag und einer nachgewiesenen ASS-Low-Response (ALR) in die Studie eingeschlossen. Entsprechend dem festgelegten Therapieplan wurde bei diesen Patienten eine Therapieanpassung durchgeführt und eine Kontrollaggregometrie zur Erfolgskontrolle durchgeführt. Das verwendete Therapieschema folgte dem Test-and-treat-Prinzip. Zur Beurteilung der Wirkung von ASS diente die Impedanzaggregometrie mittels Mehrelektrodenaggregometer (Multiplate). Ergebnisse Insgesamt konnten alle 36 Patienten erfolgreich in eine Response überführt werden. Bei 32 (88,89 %) Patienten erfolgte eine Dosiserhöhung auf 300 mg ASS, 2 (5,56 %) Patienten wurden von ASS auf Clopidogrel umgestellt. Bei weiteren 2 (5,56 %) Patienten wurde auf eine orale Antikoagulation mit Phenprocoumon aufgrund anderer Indikationen umgestellt. Blutungskomplikationen oder Nebenwirkungen traten nicht auf. Schlussfolgerung Das gewählte Therapieschema zur Behandlung einer Low-Response erwies sich als effektiv und sicher bei gefäßchirurgischen Patienten. Überwiegend führte eine leitliniengerechte Dosiserhöhung der Prophylaxe von 100 mg auf 300 mg ASS zu einer effektiven Thrombozytenaggregationshemmung in der Aggregometrie. Background A decreased antiplatelet prophylaxis (low response, LR/high on-treatment platelet reactivity, HPR) with acetylsalicylic acid (ASA) is associated with an increased risk of thromboembolic events. The prevalence of a LR is frequent with about 20% and a therapeutic regimen is not yet established. The aim of this prospective study was to evaluate the effectiveness of a therapeutic regimen for treatment adaptation when LR/HPR is detected in vascular surgery patients. Methods Overall, 36 patients under long-term antiplatelet treatment with 100 mg/day ASA and a detected ASA low response (ALR) were included in the study. In this patient group a modification of the prophylactic medication was carried out according to the established treatment plan and a control aggregometry was performed. The therapeutic regimen followed the test and treat principle. To evaluate the effect of ASA impedance, aggregometry with multiple electrodes was used (multiplate). Results All 36 patients were successfully transferred to response status with the treatment scheme. In 32 (88.89%) patients an increased dose of 300 mg/day ASA was carried out and in 2 (5.56%) patients the medication was changed from ASA to clopidogrel. A further 2 (5.56%) patients were switched to oral anticoagulation with phenprocoumon, due to other indications. Bleeding complications or other side effects did not occur. Conclusion The chosen treatment regime for a low response proved to be effective and safe in vascular surgery patients. A guideline-compliant increase of the ASA dose from 100 mg to 300 mg/day predominantly led to an effective inhibition of platelet aggregation in the aggregometry. | Evaluation einer Therapieanpassung bei ASS-Low-Response in der Gefäßchirurgie | 10.1007/s00104-020-01280-x |
2021-07-01 | This manuscript illustrates the 20-year process of establishing research sites that have been developed and maintained by the authors in collaboration with oncology colleagues at institutions in low- and middle-income countries. This infrastructure has been created for research training of US public health graduate students over the past 20 years for the Cancer Epidemiology Education in Special Populations (CEESP) Program funded by the US National Cancer Institute (R25 CA112383). We describe the history and resources that were utilized for developing and maintaining the research training infrastructure. We then define the elements needed for selecting and nurturing these global sites for education and research training of students. The elements include data and field resources, patient population, facilities for cancer management, laboratory resources, academic collaborators, and population parameters and cultural characteristics. These elements have also been essential in our US domestic training sites. We then emphasize the strengths and limitations of our global sites. Finally, we elaborate on our learning experience over the past 20 years. We believe that the material provided in this manuscript will serve as a useful toolkit for faculty, mentors, students, and trainees interested developing and/or utilizing research sites for cancer epidemiology and cancer prevention and control research training programs in global settings. | Developing and Maintaining a Global Research Training Infrastructure for Cancer Education | 10.1007/s13187-021-02033-y |
2021-07-01 | Abstract— The effect of human mast cells (MC) (HMC-1 line) on transendothelial transport (TET) of albumin and low-density lipoproteins (LDL) was studied using a two-chamber system with pores 1 μm in diameter. Human endothelial cells (EC) (line EA.hy926) were placed in the collagen-coated upper chamber and cultivated for 2–3 days until a visual monolayer was achieved. After that, 200 μg/mL LDL and 200 μg/mL albumin were added to the upper chamber. Intact MC or activated by aggregated human IgG or compound 48/80 were added to the lower chamber. Protein TET (a passage from the upper to the lower chamber through the EC monolayer) was assessed after 5 and 24 h. It turned out that the presence of MC (intact or activated) in the lower chambers retarded LDL and albumin TET after 24 h, but not after 5 h. LDL transport was found to be more sensitive to the inhibitory effect of MC than albumin transport. The suppressive effect of MC depended mainly on histamine and was canceled by histamine H1-receptor antagonist (but not of H2-receptor). | Mast Cells and Control of Transendothelial Transport: the Role of Histamine | 10.1134/S1990519X21040052 |
2021-07-01 | Herein the energies of low-lying levels, wavelengths, transition rates, and line strengths for electric dipole allowed (E1) and forbidden (M1) lines in Ne- to Al-like ions of tantalum have been calculated using the GRASP2K package, which is based on the multiconfi guration Dirac–Hartree–Fock (MCDHF) method. From our radiative decay rates, we also calculated the radiative lifetimes of some levels. The present results are in good agreement with other available theoretical and experimental values. We predict new data for several levels where no other theoretical and/or experimental results are available, stipulating the necessity of precise measurements. | Energy Levels, Wavelengths, Transition Rates, Line Strengths, and Lifetimes for Low-Lying Levels in Ne-, Na-, Mg-, and Al-Like Ions of Tantalum | 10.1007/s10812-021-01217-0 |
2021-06-30 | We consider the problem of metastability for stochastic dynamics with exponentially small transition probabilities in the low temperature limit. We generalize previous model-independent results in several directions. First, we give an estimate of the mixing time of the dynamics in terms of the maximal stability level. Second, assuming the dynamics is reversible, we give an estimate of the associated spectral gap. Third, we give precise asymptotics for the expected transition time from any metastable state to the stable state using potential-theoretic techniques. We do this in a general reversible setting where two or more metastable states are allowed and some of them may even be degenerate. This generalizes previous results that hold for a series of only two metastable states. We then focus on a specific Probabilistic Cellular Automata (PCA) with configuration space $${\mathcal {X}}=\{-1,+1\}^\varLambda $$ X = { - 1 , + 1 } Λ where $$\varLambda \subset {\mathbb {Z}}^2$$ Λ ⊂ Z 2 is a finite box with periodic boundary conditions. We apply our model-independent results to find sharp estimates for the expected transition time from any metastable state in $$\{\underline{-1}, {\underline{c}}^o,{\underline{c}}^e\}$$ { - 1 ̲ , c ̲ o , c ̲ e } to the stable state $$\underline{+1}$$ + 1 ̲ . Here $${\underline{c}}^o,{\underline{c}}^e$$ c ̲ o , c ̲ e denote the odd and the even chessboard respectively. To do this, we identify rigorously the metastable states by giving explicit upper bounds on the stability level of every other configuration. We rely on these estimates to prove a recurrence property of the dynamics, which is a cornerstone of the pathwise approach to metastability. | Effect of Energy Degeneracy on the Transition Time for a Series of Metastable States | 10.1007/s10955-021-02788-0 |
2021-06-30 | Background Obtaining instantaneous gas exchanges data is fundamental to gain information on photosynthesis. Leaf level data are reliable, but their scaling up to canopy scale is difficult as they are acquired in standard and/or controlled conditions, while natural environments are extremely dynamic. Responses to dynamic environmental conditions need to be considered, as measurements at steady state and their related models may overestimate total carbon (C) plant uptake. Results In this paper, we describe an automatic, low-cost measuring system composed of 12 open chambers (60 × 60 × 150 cm; around 400 euros per chamber) able to measure instantaneous CO 2 and H 2 O gas exchanges, as well as environmental parameters, at canopy level. We tested the system’s performance by simulating different CO 2 uptake and respiration levels using a tube filled with soda lime or pure CO 2 , respectively, and quantified its response time and measurement accuracy. We have been also able to evaluate the delayed response due to the dimension of the chambers, proposing a method to correct the data by taking into account the response time ( $${t}_{0}$$ t 0 ) and the residence time (τ). Finally, we tested the system by growing a commercial soybean variety in fluctuating and non-fluctuating light, showing the system to be fast enough to capture fast dynamic conditions. At the end of the experiment, we compared cumulative fluxes with total plant dry biomass. Conclusions The system slightly over-estimated (+ 7.6%) the total C uptake, even though not significantly, confirming its ability in measuring the overall CO 2 fluxes at canopy scale. Furthermore, the system resulted to be accurate and stable, allowing to estimate the response time and to determine steady state fluxes from unsteady state measured values. Thanks to the flexibility in the software and to the dimensions of the chambers, even if only tested in dynamic light conditions, the system is thought to be used for several applications and with different plant canopies by mimicking different environmental conditions. | A low-cost automated growth chamber system for continuous measurements of gas exchange at canopy scale in dynamic conditions | 10.1186/s13007-021-00772-z |
2021-06-30 | Background This paper describes a method to reversibly block nerve conduction through direct application of a 1 Hz sinusoidal current waveform delivered through a bipolar nerve cuff electrode. This low frequency alternating current (LFAC) waveform was previously shown to reversibly block the effects of vagal pulse stimulation evoked bradycardia in-vivo in the anaesthetised rat model ( Mintch et al. 2019 ). The present work measured the effectiveness of LFAC block on larger caliber myelinated vagal afferent fibers in human sized nerve bundles projecting to changes in breathing rate mediated by the Hering-Breuer (HB) reflex in anaesthetized domestic swine (n=5). Methods Two bipolar cuff electrodes were implanted unilaterally to the left cervical vagus nerve, which was crushed caudal to the electrodes to eliminate cardiac effects. A tripolar recording cuff electrode was placed rostral to the bipolar stimulating electrodes on the same nerve to measure changes in the compound nerve action potentials (CNAP) elicited by the vagal pulse stimulation and conditioned by the LFAC waveform. Standard pulse stimulation was applied at a sufficient level to induce a reduction in breathing rate through the HB reflex. If unblocked, the HB reflex would cause breathing to slow down and potentially halt completely. Block was quantified by the ability of LFAC to reduce the effect of the HB reflex by monitoring the respiration rate during LFAC alone, LFAC and vagal stimulation, and vagal stimulation alone. Results LFAC achieved 87.2 ±8.8% block (n=5) at current levels of 1.1 ±0.3 mA p (current to peak), which was well within the water window of the working electrode. CNAP showed changes that directly correlated to the effectiveness of LFAC block, which manifested itself as the slowing and amplitude reduction of components of the CNAP. Conclusion These novel findings suggest that LFAC is a potential alternative or complementary method to other electrical blocking techniques in clinical applications. | In-vivo application of low frequency alternating currents on porcine cervical vagus nerve evokes reversible nerve conduction block | 10.1186/s42234-021-00072-w |
2021-06-29 | It is important to avoid buckling during low-cycle fatigue testing. The buckling load is dependent on the specimen shape, material properties, and the testing machine. In the present investigation of hourglass-shaped specimens the importance of the diameter to radius of curvature is examined. Diameters of 5 and 7 mm are examined with a ratio of radius of curvature to diameter of 4, 6, and 8. The machine used is an Instron 8800 with elongated rods for a climate chamber. This leads to a reduced stiffness of the machine during compression testing. A finite element model (in Abaqus) is developed to identify the critical buckling force. For hourglass-shaped specimens, buckling means onset of sideways movement, without a drop in the applied load which is typical for conventional Euler buckling. The onset of sideways movement is identified experimentally by analysis of the data from extensometer and the load cell. This model is verified by experiments and fits within 0.6 to − 11% depending on the specimen diameter and diameter to radius of curvature ratio. The smallest deviations are obtained for the 7-mm-diameter specimen with deviation varying from 0.6 to − 3.3% between the model and the experiments. The current investigation is done with a commercially available hot rolled structural steel bar of Ø16 mm. | Prediction of buckling force in hourglass-shaped specimens | 10.1186/s40712-021-00132-8 |
2021-06-29 | Background The perspectives of low-educated employees are often neglected when designing sustainable employability (SE) interventions. As a result, the interventions offered by the employer do often not align with the needs of low-educated employees. This particular group should therefore be actively involved in the process of developing and implementing SE interventions in their work organizations. The current paper describes the development process of a web-based intervention for HR managers and direct supervisors aimed at improving the SE of low-educated employees. This intervention is specifically designed to involve low-educated employees. Methods The first four steps of the Intervention Mapping (IM) approach were used to systematically develop the intervention with the active involvement of stakeholders. Step 1 comprised a needs assessment including a literature review, empirical evidence, scoping search and several focus group interviews with employees and with representatives of employers. Step 2 formulated the intervention objective. During step 3, suitable theoretical methods were selected and translated to practical applications. Step 4 involved the development of a web-based intervention by integrating all information from the preceding steps. Results The needs assessment indicated that the employees’ active involvement and employees-employer genuine dialogue should be essential characteristics of an SE intervention for low-educated employees. The online toolkit ‘Healthy HR’ (HHR) was developed, which contains eight steps. Each step consists of one or more tasks helping the employer and employees with developing and implementing SE interventions themselves. One or more dialogue-based tools support each task. The leading principle providing structure within HHR was Adapted Intervention Mapping. Conclusion Principles of IM appeared to be useful to develop the intervention HHR systematically. This development process resulted in a practical online toolkit that supports employers in the development and implementation of local SE interventions tailored to the needs of low-educated employees. These employees should be actively involved in the process through a dialogue-based approach. By using IM principles, HHR is expected to increase the effectiveness in bettering the health and well-being of low-educated employees. | Using intervention mapping to develop ‘Healthy HR’ aimed at improving sustainable employability of low-educated employees | 10.1186/s12889-021-11278-7 |
2021-06-28 | Background The present study aimed to investigate the effects of low-level laser therapy (LLLT) on orthodontic tooth movement and its correlation with the levels of interleukin-1β (IL-1β), receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) in gingival crevicular fluid (GCF). Methods This split-mouth design study included 12 patients scheduled for the extraction of both upper first premolars. Patients were randomly selected for experimental group that received left- or right-side radiation with a diode laser (810 nm wavelength, 100 mW power output, 6.29 J/cm 2 energy density). Laser treatment was applied on days 0, 7, 14, and 21, after loading the canine retraction forces. GCF concentrations of IL-1β, RANKL, and OPG were analyzed. The upper arch of each patient was scanned with an intraoral scanner to assess tooth movement. Results The cumulative tooth movement over 28 days was significantly higher in the laser group than in the control group. We observed significant reductions in OPG levels and increases in IL-1β and RANKL levels in GCF samples on the experimental sides. Conclusion With the parameter settings used in this study, LLLT could, to some extent, lead to changes in bone metabolism, which could accelerate orthodontic tooth movement. Trial registration : Chinese Clinical Trial Registry, ChiCTR2000039594. Registered 2 November 2020—Retrospectively registered, www.chictr.org.cn/edit.aspx?pid=62465&htm=4 . | Clinical research: low-level laser therapy in accelerating orthodontic tooth movement | 10.1186/s12903-021-01684-z |
2021-06-26 | The lower Eocene-lower Miocene succession in the central part of the Al Jabal Al Akhdar, northeast Libya was investigated to determine its depositional environments and shed some light on diagenetic alterations. This succession is composed mainly of carbonate rocks and includes five formations from base to top; the Apollonia, Darnah, Al Bayda, Al Abraq, and Al Faidiyah. Relatively uniform shallow-marine carbonates were accumulated across northeast Libya, including the study area. Facies analysis of the studied carbonate rocks enables determination of four shallow-marine carbonate facies associations. These facies associations are: (1) restricted lagoon with limited circulation at/or below fair-weather wave base, (2) lagoon with open circulation below the fair-weather wave base, (3) platform-margin reefs, and (4) continental slope setting between the fair-weather and storm wave bases. The abundance of shallow marine carbonates indicates the presence of epeiric or epicontinental sea that covered the whole northern Africa. The depositional history in the studied area was controlled primarily by tectonics and relative sea-level changes. Four unconformities (i.e., sequence boundaries) were observed and separating five depositional sequences in the studied succession. Each depositional sequence shows shallowing-upward trend. The recorded unconformities reflect episodes of non-deposition and/or erosion and are associated with major fall in eustatic sea level. The diagenetic processes of the studied carbonate rocks include; micritization, pyritization, compaction, cementation, aggrading neomorphism and partial dissolution. | Facies analysis and depositional environments of the lower Eocene–lower Miocene succession in Northeast Libya | 10.1007/s13146-021-00706-9 |
2021-06-25 | Abstract High-performance electromagnetic wave absorption and electromagnetic interference (EMI) shielding materials with multifunctional characters have attracted extensive scientific and technological interest, but they remain a huge challenge. Here, we reported an electrostatic assembly approach for fabricating 2D/1D/0D construction of Ti 3 C 2 T x /carbon nanotubes/Co nanoparticles (Ti 3 C 2 T x /CNTs/Co) nanocomposites with an excellent electromagnetic wave absorption, EMI shielding efficiency, flexibility, hydrophobicity, and photothermal conversion performance. As expected, a strong reflection loss of -85.8 dB and an ultrathin thickness of 1.4 mm were achieved. Meanwhile, the high EMI shielding efficiency reached 110.1 dB. The excellent electromagnetic wave absorption and shielding performances were originated from the charge carriers, electric/magnetic dipole polarization, interfacial polarization, natural resonance, and multiple internal reflections. Moreover, a thin layer of polydimethylsiloxane rendered the hydrophilic hierarchical Ti 3 C 2 T x /CNTs/Co hydrophobic, which can prevent the degradation/oxidation of the MXene in high humidity condition. Interestingly, the Ti 3 C 2 T x /CNTs/Co film exhibited a remarkable photothermal conversion performance with high thermal cycle stability and tenability. Thus, the multifunctional Ti 3 C 2 T x /CNTs/Co nanocomposites possessing a unique blend of outstanding electromagnetic wave absorption and EMI shielding, light-driven heating performance, and flexible water-resistant features were highly promising for the next-generation intelligent electromagnetic attenuation system. Highlights The 2D/1D/0D Ti 3 C 2 T x /carbon nanotubes/Co nanocomposite is successfully synthesized via an electrostatic assembly. Nanocomposites exhibit an excellent electromagnetic wave absorption and a remarkable electromagnetic interference shielding efficiency. The flexible, waterproof, and photothermal conversion performances are achieved. | Flexible and Waterproof 2D/1D/0D Construction of MXene-Based Nanocomposites for Electromagnetic Wave Absorption, EMI Shielding, and Photothermal Conversion | 10.1007/s40820-021-00673-9 |
2021-06-24 | Time-dependent analysis based on layerwise theory (LT) along with higher-order shear deformation theory (HSDT) is studied to determine the stress distribution in a simply supported sector of spherical sandwich shell with piezoelectric face sheets and functionally graded carbon nanotube (FG-CNT) core subjected to the low-velocity impact. The aim of the current study is the investigation of the dynamic analysis of the sandwich sector when the spherical elastic ball hits the top face sheet of sector with an initial velocity of 50 m/s. The classical non-adhesive elastic contact theory and Hunter's relationship are used to calculate the normal contact pressure distribution in terms of time, as well as a function of distance from the center of contact location. The out-of-shell displacement of the sandwich shell at each layer is assumed to be a quadratic polynomial function of the radial component in addition to a function of the coordinate components within the shell. This means that the normal out-of-shell strain changes in the form of a linear function along with the thickness of each layer. The nineteen equations of motion are obtained by using Hamilton's principle, Maxwell's static equation. The numerical method was used to solve the nineteen equations of motion based on the finite difference method. The results show that the mechanical properties of FG-CNT have more effect on the stress distribution in the sandwich sector. Moreover, the variation of the voltage in terms of time caused by the impact of the spherical elastic ball was calculated. | Dynamic analysis of a spherical sandwich sector with piezoelectric face sheets and FG-CNT core subjected to low-velocity impact | 10.1007/s40430-021-03078-2 |
2021-06-24 | The wireless networks do not consider ultra-high reliability and low latency (URLL) as the primary factors. There is a delay-tolerant, non-critical content and services that are based on human-centric communication in mobile networks. The focus of the wireless networks is to provide boosted rate in data speed and increasing network coverage by using the best networking approach. The wireless communication device is primarily concerned with determining the entity’s status, by offering enhanced wireless connection assistance, and thereby raising the commodity’s status. Additionally, there will be occurrence of traffic in an infrequent manner. This adds pressure for the delivery of packets that are large or medium-sized at low latency. This is not provided by the current wireless technology system’s state of the art. This is a vital factor that challenges the future development of the wireless system for communication. Thus, to have high reliability with the irregular traffic patterns, there is a need for the development of novel and innovative technologies from physical to the network layer in the wireless communication systems. In this paper, technologies like multiple-access scheme, synchronization, multiplexing, full-duplex transmission, and channel code design are introduced for spectrally systematic ultra-high reliability and low latency communication (URLLC) in the physical layer. The techniques developed for the purpose of monitoring and controlling plant growth are called precision agricultural techniques. These techniques use actuators and sensor networks to monitor and control plant growth. Precision agriculture involves smart irrigation and fertilizer monitoring. This paper also develops a new precision agriculture technique using wireless sensor network (WSN). The WSN uses the Message Queuing Telemetry Transport (MQTT) protocol. This WSN uses IoT technology for connecting devices with the sensors for the purpose of monitoring, collecting, and distributing the data. The IoT integrates with cloud computing to subdue the limitations of IoT in monitoring and controlling systems. Thus, this paper involves the development of the UHLL communication system that can be used in precision agriculture using WSNs. | RETRACTED ARTICLE: Ultra-reliable low latency communication technique for agriculture wireless sensor networks | 10.1007/s12517-021-07576-4 |
2021-06-23 | The Ordovician reservoirs in the Tarim Basin have shown good exploration potential in recent years. To better understand its complex thermal history and further oil and gas exploration, we reconstructed the thermal evolution of the lower Paleozoic strata in Tarim Basin by applying new and previously published equivalent vitrinite reflectance (Requ), (U–Th)/He ages, and fission tracks. The modeled results indicated that there were three phases of heat flow evolution in the Tarim Basin: (1) The gradual cooling stage during Carboniferous-Ordovician, the heat flow was gradually decreasing during this period; (2) Rapidly raised stage in the early Permian period, the heat flow in Tabei and Tazhong uplift was raised rapidly during this period and the maximum is 51~62 mW/m 2 ; (3) The decline stage since Middle Permian. The tectonic activity was relatively stable and the heat flow was gradually reduced during this period. The abnormal high temperature of the Permian may be the result of the magmatic activity events. Additionally, the maturity evolution plane distribution of the bottom interface of the Lower Cambrian source rock was modeled based on the new thermal histories, suggesting that the source rocks experienced rapid heating during the Caledonian period, and entered the hydrocarbon generation stage at the end of Ordovician. In the end of Mesozoic, the Cambrian source rocks reached the dry gas stage in the south of Shuntuoguole low uplift, Manjiaer depression, Tadong uplift, and Kongquehe slope. Currently, the maturity mostly maintained the characteristics of the end of the Mesozoic. The thermal history and maturity histories of the lower Paleozoic source rock in Tarim Basin provide new insights to guide oil and gas exploration of the basin. | Thermal evolution and the maturation of the deeply buried lower Paleozoic source rocks in the Tarim Basin, northwest China | 10.1007/s12517-021-07562-w |
2021-06-22 | Studies have shown that rubberised concrete is a potential pavement material. Pavement materials are generally expected to possess concrete with high impact resistance, especially in regions where winter temperatures remain lower than the freezing point for long periods. However, knowledge about the performance of rubberised concrete on impact under low temperatures is still limited. In this study, experiments were conducted to evaluate the compressive strength, elasticity modulus, bending strength, and impact resistance of rubberised concrete at room temperature (20 °C) and at a sub-zero temperature (− 20 °C). Meanwhile, a new U-shaped specimen drop-weight test was performed as an impact test. The results indicated that although the impact toughness of both rubberised and plain concrete types decreased at low temperatures, rubber particles also had positive effects on concrete impact resistance at − 20 °C. In addition to macroscopic tests, mercury injection and molecular dynamics simulations were performed to understand the mechanism through which rubber particles improve the impact resistance of concrete at low temperatures. The pores that could not freeze accounted for 1.55% of the total pores in plain concrete; this value was 2.36% in concrete with a rubber particle density of 50 kg/m 3 . From the results of this study, we can conclude that the addition of rubber can change the distribution of water or ice in concrete pores, which leads to an improvement in the toughness of concrete at a low temperature (− 20 °C). | Effect of rubber particles on impact resistance of concrete at a temperature of − 20 ℃ | 10.1007/s43452-021-00257-9 |
2021-06-22 | Background To date (April 2021), medical device (MD) design approaches have failed to consider the contexts where MDs can be operationalised. Although most of the global population lives and is treated in Low- and Middle-Income Countries (LMCIs), over 80% of the MD market share is in high-resource settings, which set de facto standards that cannot be taken for granted in lower resource settings. Using a MD designed for high-resource settings in LMICs may hinder its safe and efficient operationalisation. In the literature, many criteria for frameworks to support resilient MD design were presented. However, since the available criteria (as of 2021) are far from being consensual and comprehensive, the aim of this study is to raise awareness about such challenges and to scope experts’ consensus regarding the essentiality of MD design criteria. Results This paper presents a novel application of Delphi study and Multiple Criteria Decision Analysis (MCDA) to develop a framework comprising 26 essential criteria, which were evaluated and chosen by international experts coming from different parts of the world. This framework was validated by analysing some MDs presented in the WHO Compendium of innovative health technologies for low-resource settings. Conclusions This novel holistic framework takes into account some domains that are usually underestimated by MDs designers. For this reason, it can be used by experts designing MDs resilient to low-resource settings and it can also assist policymakers and non-governmental organisations in shaping the future of global healthcare. | A framework for designing medical devices resilient to low-resource settings | 10.1186/s12992-021-00718-z |
2021-06-22 | Two-dimensional numerical investigations are carried out to understand the effect of rotation on flow characteristics over two identical circular cylinders in an unconfined medium at low Reynolds number. Both the cylinders are placed in tandem arrangement transverse to the incoming flow, and the dimensionless spacing between the cylinders is varied in the range $$0.2 \le g* \le 3.0$$ 0.2 ≤ g ∗ ≤ 3.0 . Unsteady laminar incompressible flow computations are performed for all spacings using a finite volume technique at constant Reynolds number (Re = 100) and Prandtl number (Pr = 0.71). The upstream and downstream cylinders are made to rotate in the clockwise and counterclockwise directions, respectively. Results show that the counter rotation brings stability in the flow field around the cylinders, which in turn alters the fluid flow and heat transfer characteristics. At some point of the rotation rate, irrespective of the direction of rotation, the flow permutes from unsteady periodic vortex shedding to the steady state. Moreover, the critical rotational speed slightly decreases with gap spacing and shoots up at larger gap spacing. | Influence of counter rotation on fluid flow and heat transfer around tandem circular cylinders at low Reynolds number | 10.1007/s40430-021-03072-8 |
2021-06-22 | In this article, we investigate the formation and disruption of a coronal sigmoid from the active region (AR) NOAA 11909 on 07 December 2013, by analyzing multi-wavelength and multi-instrument observations. Our analysis suggests that the formation of the sigmoid initiated ≈ 1 hour before its eruption through a coupling between two twisted coronal loop systems. This sigmoid can be well regarded as of ‘transient’ class due to its short lifetime as the eruptive activities started just after ≈ 20 min of its formation. A comparison between coronal and photospheric images suggests that the coronal sigmoid was formed over a simple β $\beta $ -type AR which also possessed dispersed magnetic field structure in the photosphere. The line-of-sight photospheric magnetograms also reveal small-scale flux cancellation events near the polarity inversion line, and overall flux cancellation during the extended pre-eruption phase which suggest the role of tether-cutting reconnection toward the build-up of the flux rope. The disruption of the sigmoid proceeded with a two-ribbon eruptive M1.2 flare (SOL2013-12-07T07:29). In radio frequencies, we observe type III and type II bursts in meter wavelengths during the impulsive phase of the flare. The successful eruption of the flux rope leads to a fast coronal mass ejection (with a linear speed of ≈ 1085 km s −1 ) in SOHO/LASCO field-of-view. During the evolution of the flare, we clearly observe typical “sigmoid-to-arcade” transformation. Prior to the onset of the impulsive phase of the flare, flux rope undergoes a slow rise (≈ 15 km s −1 ) which subsequently transitions into a fast eruption (≈ 110 km s −1 ). The two-phase evolution of the flux rope shows temporal associations with the soft X-ray precursor and impulsive phase emissions of the M-class flare, respectively, thus pointing toward a feedback relationship between magnetic reconnection and early CME dynamics. | A Transient Coronal Sigmoid in Active Region NOAA 11909: Build-up Phase, M-class Eruptive Flare, and Associated Fast Coronal Mass Ejection | 10.1007/s11207-021-01830-4 |
2021-06-21 | Background Tetanus remains common in many low- and middle-income countries, but as critical care services improve, mortality from tetanus is improving. Nevertheless, patients develop severe syndromes associated with autonomic nervous system disturbance (ANSD) and the requirement for mechanical ventilation (MV). Understanding factors associated with worse outcome in such settings is important to direct interventions. In this study, we investigate risk factors for disease severity and long-term physical outcome in adults with tetanus admitted to a Vietnamese intensive care unit. Methods Clinical and demographic variables were collected prospectively from 180 adults with tetanus. Physical function component scores (PCS), calculated from Short Form Health Survey (SF-36), were assessed in 79 patients at hospital discharge, 3 and 6 months post discharge. Results Age, temperature, heart rate, lower peripheral oxygen saturation (SpO 2 ) and shorter time from first symptom to admission were associated with MV (OR 1.03 [ 95% confidence interval (CI) 1.00, 1.05], p = 0.04; OR 2.10 [95% CI 1.03, 4.60], p = 0.04; OR 1.04 [ 95% CI 1.01, 1.07], p = 0.02); OR 0.80 [95% CI 0.66, 0.94], p = 0.02 and OR 0.65 [95% CI 0.52, 0.79, p < 0.001, respectively). Heart rate, SpO 2 and time from first symptom to admission were associated with ANSD (OR 1.03 [95% CI 1.01, 1.06], p < 0.01; OR 0.95 [95% CI 0.9, 1.00], p = 0.04 and OR 0.64 [95% CI 0.48, 0.80], p < 0.01, respectively). Median [interquartile range] PCS at hospital discharge, 3 and 6 months were 32.37 [24.95–41.57, 53.0 [41.6–56.3] and 54.8 [51.6–57.3], respectively. Age, female sex, admission systolic blood pressure, admission SpO 2 , MV, ANSD, midazolam requirement, hospital-acquired infection, pressure ulcer and duration of ICU and hospital stay were associated with reduced 0.25 quantile PCS at 6 months after hospital discharge. Conclusions MV and ANSD may be suitable endpoints for future research. Risk factors for reduced physical function at 3 months and 6 months post discharge suggest that modifiable features during hospital management are important determinants of long-term outcome. | Risk factors associated with mechanical ventilation, autonomic nervous dysfunction and physical outcome in Vietnamese adults with tetanus | 10.1186/s41182-021-00336-w |
2021-06-20 | Low condition of dissolved oxygen (DO) is commonly associated with sludge bulking problem that was able to disrupt the efficiency of wastewater treatment performances. Relatively, very little attention was paid to the possibility of applying magnetic field in controlling the bulking problem. Hence, this study aims to investigate the performance of magnetic field on biomass properties and its effect on biodegradation under low condition of DO. Two continuous laboratory-scale sequencing batch reactors—Reactor A (SBR A ) and Reactor B (SBR B )—were setup. SBR A was equipped with the magnetic device to exhibit magnetic field of 88 mT, while SBR B acted as a control system. The results showed that the biomass concentration in SBR A was higher compared to SBR B . High biomass concentration in SBR A resulted to better settleability with mean SVI of less than 30 mL/g. SBR A also showed consistently high removal performances of organic and inorganic contents compared to SBR B . These observations confirmed that the magnetic field was able to enhance the biomass properties, which further enhance the biodegradation ability of the aerobic bacteria under low DO condition. This also indicates that under the sludge bulking circumstances, the use of magnetic field stands a great chance in maintaining high biodegradation of the treatment system. | Effect of magnetic field on biomass properties and their role in biodegradation under condition of low dissolved oxygen | 10.1007/s13201-021-01439-9 |
2021-06-19 | The entry of blood-borne molecules into the brain is restricted by the blood–brain barrier (BBB). Various physical, transport and immune properties tightly regulate molecule movement between the blood and the brain to maintain brain homeostasis. A recent study utilizing a pan-endothelial, constitutive Tie2-Cre showed that paracellular passage of blood proteins into the brain is governed by endocytic and cell signaling protein low-density lipoprotein receptor–related protein 1 (LRP1). Taking advantage of conditional Slco1c1-CreER T2 specific to CNS endothelial cells and choroid plexus epithelial cells we now supplement previous results and show that brain endothelial Lrp1 ablation results in protease-mediated tight junction degradation, P-glycoprotein (P-gp) reduction and a loss of BBB integrity. | Brain endothelial LRP1 maintains blood–brain barrier integrity | 10.1186/s12987-021-00260-5 |
2021-06-17 | In order to visualize the rarefied flow field in a Φ1m hypersonic low-density wind tunnel, an electric glow discharge technique based on high frequency excited power has been developed. Firstly, finite element simulation analysis has been carried out, and it is concluded that the breakdown voltage can be reduced by using high frequency power supply; then an electric glow discharge apparatus has been fabricated, and the discharge images were compared with simulations; besides, a clear flow field around HB-1 standard model has been observed using this technology; finally, the influence of glow discharge on the flow field, as well as the differences between direct current and high frequency electric glow discharges is discussed at the end of this paper. | High frequency AC electric glow discharge visualization technology and application in big diameter hypersonic low-density wind tunnel | 10.1186/s42774-021-00067-w |
2021-06-17 | Bulk rock geochemical characteristics and Sr–Nd isotopic data were used as a proxy to evidently ascertain the adakitic affinity or signature of the basement rock samples from the Mbengwi region, located within the Pan-African North Equatorial fold belt. In the present study, numerous granitoids display low MgO (<3.0 wt.%) and Mg# (mostly < 45), moderate to high Sr/Y (avg.: 23), moderate to high La/Yb (avg.: 62), high Zr/Sm (10.86–328.9; avg.: 43.8) high Na 2 O contents (2.2–5.5 wt.%) and 87 Sr/ 86 Sr ≤0.7045 in addition to high K 2 O/Na 2 O (avg.: 1.5) ratio, typical of adakites or adakite-like rocks. The samples referred to as adakite-like are assigned both as K-rich adakite and high-Si adakite (HSA), and consequently of crustal origin. The large variation of Sr/Y and La/Yb ratios, the range of their Rb/Sr ratio (0.27–0.53) in addition to the plots of bulk rocks Mg number, FeO T /MgO and MgO vs. SiO 2 likewise evidence that they are mainly C-type adakitic rocks, and almost all derived from partial melt of lower thickened crust. | Evidence of adakitic signature in Pan-African basement rocks from the Mbengwi region (NW Cameroon): constraints from whole rock chemistry and Sr–Nd isotopes | 10.1007/s12517-021-07541-1 |
2021-06-15 | In the present work, the structural and optical properties of the pristine and argon (Ar) ion irradiated RF-sputtered ZnO thin films have been studied using X-ray diffraction (XRD), UV–visible spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The ion irradiation was performed at a constant fluence of 5 × 10 15 ions/cm 2 , and the incident ion energy was varied from 300 keV to 1 MeV. The XRD pattern of the pristine ZnO film shows amorphous-like behavior, whereas ion irradiated films exhibit the evolution of hexagonal wurtzite structure along c-axis (002) orientation at higher energies. The crystallinity of the films was found to improve with the ion irradiation at increased energy, and the crystallite size varies from 5.4 to 23.0 nm. The surface features of the pristine and ion irradiated films were recorded by SEM and AFM both. The 3 D images show growth of cone-like structure with enhanced energy-dependent ion irradiation. However, beyond 800 keV, dissolution of grains was noticed. With UV–visible spectroscopy, the transparency of the films was noticed to decrease with increasing the incident ion energy, and the optical band gap as measured using Tauc plots was found to vary from 3.31 to 3.26 eV. With chosen incident ion energies, viz. 300 keV, 550 keV, 800 keV, and 1 MeV, the ratio of the electronic to nuclear energy loss (Se/Sn) takes the value of 1, 2, 3, and 4 as deduced using SRIM Monte-Carlo simulation program and, and this provides us a probe to verify the synergistic effect of ion irradiation in tailoring the properties of ZnO. The ion-induced tunability of the structural and optical properties in such oxide films facilitates the wide range of applications mainly the piezoelectric transduction mechanism and fabrication of optoelectronics devices. | Structural and optical modifications of RF-sputtered ZnO thin films using low energy Ar ion irradiation | 10.1007/s00339-021-04685-5 |
2021-06-14 | Cenomanian strata of the Elbtal Group (Saxony, eastern Germany) reflect a major global sea-level rise and contain, in certain intervals, a green authigenic clay mineral in abundance. Based on the integrated study of five new core sections, the environmental background and spatio-temporal patterns of these glauconitic strata are reconstructed and some general preconditions allegedly needed for glaucony formation are critically questioned. XRD analyses of green grains extracted from selected samples confirm their glauconitic mineralogy. Based on field observations as well as on the careful evaluation of litho- and microfacies, 12 glauconitc facies types (GFTs), broadly reflecting a proximal–distal gradient, have been identified, containing granular and matrix glaucony of exclusively intrasequential origin. When observed in stratigraphic succession, GFT-1 to GFT-12 commonly occur superimposed in transgressive cycles starting with the glauconitic basal conglomerates, followed up-section by glauconitic sandstones, sandy glauconitites, fine-grained, bioturbated, argillaceous and/or marly glauconitic sandstones; glauconitic argillaceous marls, glauconitic marlstones, and glauconitic calcareous nodules continue the retrogradational fining-upward trend. The vertical facies succession with upwards decreasing glaucony content demonstrates that the center of production and deposition of glaucony in the Cenomanian of Saxony was the nearshore zone. This time-transgressive glaucony depocenter tracks the regional onlap patterns of the Elbtal Group, shifting southeastwards during the Cenomanian 2nd-order sea-level rise. The substantial development of glaucony in the thick (60 m) uppermost Cenomanian Pennrich Formation, reflecting a tidal, shallow-marine, nearshore siliciclastic depositional system and temporally corresponding to only ~ 400 kyr, shows that glaucony formation occurred under wet, warm-temperate conditions, high accumulation rates and on rather short-term time scales. Our new integrated data thus indicate that environmental factors such as great water depth, cool temperatures, long time scales, and sediment starvation had no impact on early Late Cretaceous glaucony formation in Saxony, suggesting that the determining factors of ancient glaucony may be fundamentally different from recent conditions and revealing certain limitations of the uniformitarian approach. | Depositional setting and limiting factors of early Late Cretaceous glaucony formation: implications from Cenomanian glauconitic strata (Elbtal Group, Germany) | 10.1007/s10347-021-00627-y |
2021-06-12 | The synthesis of novel architecture comprising perylene diimide (PDI)-MXene (Ti 3 C 2 T X )-integrated graphitic pencil electrode for electrochemical detection of dopamine (DA) is reported. The good electron passage between PDI-MXene resulted in an unprecedented nano-adduct bearing enhanced electrocatalytic activity with low-energy electronic transitions. The anionic groups of PDI corroborated enhanced active surface area for selective binding and robust oxidation of DA, thereby decreasing the applied potential. Meanwhile, the MXene layers acted as functional conducive support for PDI absorption via strong H-bonding. The considerable conductivity of MXene enhanced electron transportation thus increasing the sensitivity of sensing interface. The inclusively engineered nano-adduct resulted in robust DA oxidation with ultra-sensitivity (38.1 μAμM −1 cm −2 ), and low detection limit (240 nM) at very low oxidation potential (−0.135 V). Moreover, it selectively signaled DA in the presence of physiological interferents with wide linearity (100–1000 μM). The developed transducing interface performed well in human serum samples with RSD (0.1 to 0.4%) and recovery (98.6 to 100.2%) corroborating the viability of the practical implementation of this integrated system. Graphical abstract Schematic illustration of the oxidative process involved on constructed sensing interface for the development of a non-enzymatic dopamine sensor. | Perylene diimide/MXene-modified graphitic pencil electrode-based electrochemical sensor for dopamine detection | 10.1007/s00604-021-04884-0 |
2021-06-12 | This paper reports on the design, fabrication, RF measurement, and high-power test of a prototype accelerator—such as 11.424 GHz with 12 cells—and a traveling wave of two halves. It was found that the unloaded gradient reached 103 MV/m during the high-power test and the measured breakdown rate, after $$3.17\times 10^7$$ 3.17 × 10 7 pulses, was $$1.62\times 10^{-4}$$ 1.62 × 10 - 4 /pulse/m at 94 MV/m and a 90 ns pulse length. We thus concluded that the high-gradient two-half linear accelerator is cost-effective, especially in high-frequency RF linear acceleration. Finally, we suggest that silver-based alloy brazing can further reduce costs. | Development and high-gradient test of a two-half accelerator structure | 10.1007/s41365-021-00895-x |
2021-06-11 | Nano-composites are emerging class of materials with venerable physical and chemical properties useful for gas sensor applications. In the present work, we have successfully demonstrated utilization of TiO 2 nano-tube and hydroxyapatite nano-composite thick films for sensing of alcohol vapours at lower temperature and lower concentrations. Various composites have been prepared by adding wt.% TiO 2 nano-tube in hydroxyapatite host material. Various characterizations like XRD, TGA, FTIR and SEM were performed to know structural identification, thermal stability, functional groups and surface morphology, respectively. Among all composites, the 2 wt.% TiO 2 nano-tube-hydroxyapatite nano-composite film exhibits pronounced sensing behaviour for the detection of alcohol vapour even at 10 ppm. The operating temperature was observed to be 30/45/105 °C for methanol/ethanol/propanol, whereas, for the same nano-composite material there was fast response and recovery time (100 and 30)/(110 and 40)/(180 and 90) seconds, respectively. These results concluded that nano-composite of TiO 2 nano-tube and hydroxyapatite is capable of sensing alcohol vapours with their existence in ambient conditions as low as 10 ppm concentration compared to their native counterparts. | Enhancing alcohol sensing properties of hydroxyapatite via synthesis of its composite with TiO2 nano-tube | 10.1007/s00339-021-04660-0 |
2021-06-09 | A newly collected specimen of the enigmatic coleoid genus Longibelus is recorded from lower Turonian strata along the River Shadrinka in Sakhalin (Russian Far East). To date, this is the first record of Late Cretaceous coleoid cephalopods from the island and, in fact, from the entire Pacific coast of the Russian Federation. Lithological characteristics, coupled with published geochemical analyses (δ 13 C and C org content), suggest the habitat of this coleoid taxon to have been the middle to outer (i.e. distal) shelf. Its provenance from the stratigraphical level that is known as the Scaphites Event, characterised by a mass occurrence of Scaphites and Yesoites , may be indicative of occasional or marginal overlap in ranges, rather than life in similar habitats. On the basis of lithological features and in view of the extremely rare occurrence of Longibelus in rich ammonite assemblages with clear ecological/bathymetric preferences, the natural habitat of Longibelus may have comprised neritic to mesopelagic zones over distal shelves and slopes. | First record of the enigmatic coleoid genus Longibelus from Sakhalin (Far East Russia): a contribution to our understanding of Cretaceous coleoid habitats in the Pacific Realm | 10.1186/s13358-021-00227-x |
2021-06-07 | Aiming at the problem that the coal seam temperature is high and the gas desorption rate is fast, the gas content loss is estimated to be biased, resulting in inaccurate measurement of coal seam gas content. This paper proposes a method for taking the coal samples at low temperature (below 0 °C) in order to improve the accuracy of gas content measurement by suppressing the release of gas. Based on the importance of gas adsorption desorption in the prediction of gas diffusion law in coal, this paper analyzes the gas adsorption/desorption characteristics of standard size raw coal in low-temperature environment with self-designed low-temperature environment gas adsorption/desorption test platform. Experimental study has been conducted on the gas adsorption promotion and desorption restrain of environmental coal. The results show that (1) the temperature increase promotes the adsorption of coal to gas. The lower the temperature is, the more obvious the adsorption effect will be; and the lower the temperature inhibits the gas desorption; likewise the lower the temperature is, the more obvious the restrain of desorption will be. (2) The gas desorption rate of coal can be divided into three significant stages. Among them, stage I has the shortest time, the desorption rate is the largest, and the gas desorption amount is the most; stage III is the longest, the gas desorption rate is the second, and the gas desorption amount is the middle; stage II desorption rate is the smallest, and the desorption amount is the least. (3) Lowering the temperature has different effects on the gas desorption rate of coal in three stages. The gas desorption rate of the coal in the first stage is mainly suppressed, and the gas desorption rate data has a quadratic function increasing with the increase of the adsorption equilibrium temperature. However, the gas desorption in the second and third stages of coal is a promoting effect, and the gas desorption rate data decreases with the increase of the adsorption equilibrium temperature. (4) The research on the gas desorption restrain effect of low temperature environment coal will provide theoretical basis for the development and application of underground cryo-coring technology. | Experimental study on adsorption promotion and desorption restrain of gas-containing coal in low-temperature environment | 10.1007/s12517-021-07477-6 |
2021-06-04 | Background Diagnosing bacterial meningitis is essential to optimise the type and duration of antimicrobial therapy to limit mortality and sequelae. In sub-Saharan Africa, many public hospitals lack laboratory capacity, relying on clinical features to empirically treat or not treat meningitis. We investigated whether clinical features of bacterial meningitis identified prior to the introduction of conjugate vaccines still discriminate meningitis in children aged ≥60 days. Methods We conducted a retrospective cohort study to validate seven clinical features identified in 2002 ( KCH-2002 ): bulging fontanel, neck stiffness, cyanosis, seizures outside the febrile convulsion age range, focal seizures, impaired consciousness, or fever without malaria parasitaemia and Integrated Management of Childhood Illness (IMCI) signs: neck stiffness, lethargy, impaired consciousness or seizures, and assessed at admission in discriminating bacterial meningitis after the introduction of conjugate vaccines. Children aged ≥60 days hospitalised between 2012 and 2016 at Kilifi County Hospital were included in this analysis. Meningitis was defined as positive cerebrospinal fluid (CSF) culture, organism observed on CSF microscopy, positive CSF antigen test, leukocytes ≥50/μL, or CSF to blood glucose ratio <0.1. Results Among 12,837 admissions, 98 (0.8%) had meningitis. The presence of KCH-2002 signs had a sensitivity of 86% (95% CI 77–92) and specificity of 38% (95% CI 37–38). Exclusion of ‘fever without malaria parasitaemia’ reduced sensitivity to 58% (95% CI 48–68) and increased specificity to 80% (95% CI 79–80). IMCI signs had a sensitivity of 80% (95% CI 70–87) and specificity of 62% (95% CI 61–63). Conclusions A lower prevalence of bacterial meningitis and less typical signs than in 2002 meant the lower performance of KCH-2002 signs. Clinicians and policymakers should be aware of the number of lumbar punctures (LPs) or empirical treatments needed for each case of meningitis. Establishing basic capacity for CSF analysis is essential to exclude bacterial meningitis in children with potential signs. | Clinical features of bacterial meningitis among hospitalised children in Kenya | 10.1186/s12916-021-01998-3 |
2021-06-03 | Intended for human consumption water resources are rapidly decreased due to overuse, global warming and also polluting by pollutants. Metal concentrations are generally removed by precipitation, adsorption, biosorption and some chemical reactions in the receiving water media. Therefore, polluted waters by metals are caused to rarely toxic effects in living things in high concentrations. Metal polluted waters are generally caused to esthetic and cosmetic effects. Adsorption is one of the commonly used methods for metal removal. In recent years, researches about natural low cost adsorbents are increased. Factors such as modification and electricity costs increase the cost of adsorbent. In this study, dry acorn caps of Quercus robur were used as non-modify natural adsorbent. The batch experiments were carried out to removal of copper in water that has initial low concentration by prepared natural adsorbent. It was performed equilibrium, kinetics, thermodynamic studies and moreover adsorbent characterization studies with using SEM + EDX and XRD methods. It was found the removal efficiency was 84%, and adsorption capacity was 0.336 mg/g. This paper is aimed to expressing the affecting factors of adsorption mechanism at the removal of copper in water. This paper is expressing the affecting factors of a non-modify natural adsorbent's adsorption mechanism at the removal of copper in water which has initial low concentration. As a consequence, it has been seen that acorn caps of Quercus robur due to contained tannins highly effects adsorption mechanism, and it may be used of copper removal. | Investigation of Copper removal mechanisms on Quercus robur acorn caps: Equilibrium, kinetics, thermodynamic and characterization studies | 10.1007/s13201-021-01434-0 |
2021-06-03 | Here we report a comprehensive numerical study for the operating behavior and physical mechanism of nitride micro-light-emitting-diode (micro-LED) at low current density. Analysis for the polarization effect shows that micro-LED suffers a severer quantum-confined Stark effect at low current density, which poses challenges for improving efficiency and realizing stable full-color emission. Carrier transport and matching are analyzed to determine the best operating conditions and optimize the structure design of micro-LED at low current density. It is shown that less quantum well number in the active region enhances carrier matching and radiative recombination rate, leading to higher quantum efficiency and output power. Effectiveness of the electron blocking layer (EBL) for micro-LED is discussed. By removing the EBL, the electron confinement and hole injection are found to be improved simultaneously, hence the emission of micro-LED is enhanced significantly at low current density. The recombination processes regarding Auger and Shockley–Read–Hall are investigated, and the sensitivity to defect is highlighted for micro-LED at low current density. Synopsis : The polarization-induced QCSE, the carrier transport and matching, and recombination processes of InGaN micro-LEDs operating at low current density are numerically investigated. Based on the understanding of these device behaviors and mechanisms, specifically designed epitaxial structures including two QWs, highly doped or without EBL and p-GaN with high hole concentration for the efficient micro-LED emissive display are proposed. The sensitivity to defect density is also highlighted for micro-LED. | Designs of InGaN Micro-LED Structure for Improving Quantum Efficiency at Low Current Density | 10.1186/s11671-021-03557-4 |
2021-06-02 | Background Flavonoids can protect plants against extreme temperatures and ROS due to their antioxidant activities. We found that deep-purple seed coat color was controlled by two gene interaction (12:3:1) from the cross between yellow and deep-purple seed coat colored inbreds. F 2:3 seeds were grouped in 3 by seed coat color and germinated under chilling (4 °C) and non-acclimated conditions (18 °C) for a week, followed by normal conditions (18 °C) for three weeks and a subsequent chilling stress (4 °C) induction. We analyzed mean daily germination in each group. Additionally, to study the acclimation in relationship to the different seed coat colors on the germination ability and seedling performances under the cold temperatures, we measured the chlorophyll content, ROS scavenging activity, and expression levels of genes involved in ROS scavenging, flavonoid biosynthetic pathway, and cold response in seedlings. Results The results of seed color segregation between yellow and deep purple suggested a two-gene model. In the germination study, normal environmental conditions induced the germination of yellow-seed, while under chilling conditions, the germination ratio of deep purple-seed was higher than that of yellow-colored seeds. We also found that the darker seed coat colors were highly responsive to cold acclimation based on the ROS scavenging enzymes activity and gene expression of ROS scavenging enzymes, flavonoid biosynthetic pathway and cold responsive genes. Conclusions We suggest that deep purple colored seed might be in a state of innate pre-acquired stress response state under normal conditions to counteract stresses in a more effective way. Whereas, after the acclimation, another stress should enhance the cold genes expression response, which might result in a more efficient chilling stress response in deep purple seed seedlings. Low temperature has a large impact on the yield of crops. Thus, understanding the benefit of seed coat color response to chilling stress and the identification of limiting factors are useful for developing breeding strategies in order to improve the yield of wheat under chilling stress. | Effect of chilling acclimation on germination and seedlings response to cold in different seed coat colored wheat (Triticum aestivum L.) | 10.1186/s12870-021-03036-z |
2021-06-01 | In this study, ceramics was prepared by slip casting (no pressure was used during shaping step) and atmospheric pressure sintering with low-melting point glass (LPG) powder as the binding material to facilitate the transformation of spodumene flotation tailings (SFTs) into ceramics at lower temperatures. The influence of sintering temperature and mass ratio of LPG on the mechanical properties (flexural strength and compressive strength) of ceramic materials was studied by orthogonal test. The results showed that when the mass ratio of LPG powder was higher than or equal to 20 wt% and the sintering temperature was higher than or equal to 550 °C, mutual adhesion between the sample particles was realised and consequently the ceramic materials could be prepared with good mechanical properties (the maximum flexural strength=19.55 MPa, the maximum compressive strength=42.25 MPa, average porosity=24.52%, average apparent density=1.66 g/cm 3 , and average water absorption=14.79%). The sintered ceramics were characterized by XRF, XRD, optical microscopy analysis, SEM, TGA-DSC and FT-IR. The formation of liquid phase at high temperature may lead to the mutual bonding between particles, which might be the main reason for the improvement of mechanical properties of ceramic materials. Overall, SFTs were successfully sintered at low temperature to prepare ceramic materials with good mechanical properties, which are crucial for energy conservation and environmental preservation. 本文以锂辉石浮选尾矿为主要原料, 低熔点玻璃粉(LPG)为高温粘结材料, 通过湿法注模成型, 常压烧结制备陶瓷材料。通过正交试验研究了烧结温度和LPG 质量分数对陶瓷材料抗折强度和抗压 强度的影响。结果表明, 当LPG 质量比不低于20 wt%, 烧结温度不低于550 °C 时, 尾矿颗粒间相互 粘结紧密, 制备出了力学性能优异的陶瓷材料(最大抗折强度=19.55 MPa, 最大抗压强度= 42.25 MPa, 平均显气孔率24.52%, 体积密度1.66 g/cm 3 , 吸水率14.79%)。采用XRF, XRD, 光学显微镜, SEM, TGA-DSC 和FT-IR 等对陶瓷材料低温烧结机理进行了测试分析。结果表明, 高温下液相的生成使得 颗粒间相互粘结可能为陶瓷材料力学性能提高的主要原因。 | Sintering behavior and mechanical properties of sintered ceramics based on spodumene tailings | 10.1007/s11771-021-4723-9 |
2021-06-01 | This work presents a simulation study of the influence of temperature on the performance of dual material gate (DMG) vertical super-thin body (VSTB) FET. The introduction of DMG causes a drop in the off-state current (I off ) by ~99.18% and DIBL by 20%. Drop in the I off enhances the on-to-off current ratio (I on /I off ) by ~98.85%. A rigorous investigation on temperature dependency of DC, analog/RF, and linearity metrics was carried out. The zero temperature coefficient (ZTC) bias point for the DMG device was observed to be nearly at a gate bias of V G = 0.41 V. Various DC figures of merit (FoM) such as subthreshold swing (SS), I on /I off , and threshold voltage (V T ) show improvement with temperature fall. Lowering in temperature also leads to enhanced analog/RF performance by offering superior g m , g d , C gg , C gd , maximum f T , maximum GBP, intrinsic delay, TGF, TFP, GFP, and GTFP. However, linearity metrics like g m2 , g m3 , VIP2, VIP3, IIP 3 , IMD 3 , and 1-dB compression point show better performance with an increase in temperature. | Study of Temperature Effect on Analog/RF and Linearity Performance of Dual Material Gate (DMG) Vertical Super-Thin Body (VSTB) FET | 10.1007/s12633-020-00561-8 |
2021-06-01 | Y 2 O 3 is regarded as one of the potential environmental barrier coating (EBC) materials for Al 2 O 3f /Al 2 O 3 ceramic matrix composites owing to its high melting point and close thermal expansion coefficient to Al 2 O 3 . However, the relatively high thermal conductivity and unsatisfactory calcium-magnesium-aluminosilicate (CMAS) resistance are the main obstacles for the practical application of Y 2 O 3 . In order to reduce the thermal conductivity and increase the CMAS resistance, four cubic bixbyite structured high-entropy oxides RE 2 O 3 , including (Eu 0.2 Er 0.2 Lu 0.2 Y 0.2 Yb 0.2 ) 2 O 3 , (Sm 0.2 Er 0.2 Lu 0.2 Y 0.2 Yb 0.2 ) 2 O 3 , (Sm 0.2 Eu 0.2 Er 0.2 Y 0.2 Yb 0.2 ) 2 O 3 , and (Sm 0.2 Eu 0.2 Lu 0.2 Y 0.2 Yb 0.2 ) 2 O 3 were designed and synthesized, among which (Eu 0.2 Er 0.2 Lu 0.2 Y 0.2 Yb 0.2 ) 2 O 3 and (Sm 0.2 Er 0.2 Lu 0.2 Y 0.2 Yb 0.2 ) 2 O 3 bulks were prepared by spark plasma sintering (SPS) to investigate their mechanical and thermal properties as well as CMAS resistance. The mechanical properties of (Eu 0.2 Er 0.2 Lu 0.2 Y 0.2 Yb 0.2 ) 2 O 3 and (Sm 0.2 Er 0.2 Lu 0.2 Y 0.2 Yb 0.2 ) 2 O 3 are close to those of Y 2 O 3 but become more brittle than Y 2 O 3 . The thermal conductivities of (Eu 0.2 Er 0.2 Lu 0.2 Y 0.2 Yb 0.2 ) 2 O 3 and (Sm 0.2 Er 0.2 Lu 0.2 Y 0.2 Yb 0.2 ) 2 O 3 (5.1 and 4.6 W·m −1 ·K −1 ) are only 23.8% and 21.5% respectively of that of Y 2 O 3 (21.4 W·m −1 ·K −1 ), while their thermal expansion coefficients are close to those of Y 2 O 3 and Al 2 O 3 . Most importantly, HE RE 2 O 3 ceramics exhibit good CMAS resistance. After being attacked by CMAS at 1350 °C for 4 h, the HE RE 2 O 3 ceramics maintain their original morphologies without forming pores or cracks, making them promising as EBC materials for Al 2 O 3f /Al 2 O 3 composites. | Preparation and properties of CMAS resistant bixbyite structured high-entropy oxides RE2O3 (RE = Sm, Eu, Er, Lu, Y, and Yb): Promising environmental barrier coating materials for Al2O3f/Al2O3 composites | 10.1007/s40145-021-0461-6 |
2021-06-01 | Metal sulfides with high specific capacities have drawn considerable attention in the field of sodium-ion batteries (SIBs). As a typical metal sulfide, FeV 2 S 4 always suffers rapid decay of capacities because of its low stability arising from large volume change. FeV 2 S 4 nanoparticles with controllable sizes and distribution are encapsulated in carbon nanofibers (CNFs) with the help of graphene oxide (GO) to fabricate FeV 2 S 4 @GO@CNF. As a result, FeV 2 S 4 @GO@CNF anodes show enhanced electrochemical performances for Na + storage when compared with FeV 2 S 4 @CNF with more particles on the surface. Typically, the capacity of FeV 2 S 4 @GO@CNF can be maintained at 411 mA h g −1 after 200 cycles (0.1 A g −1 ) and 227 mA h g −1 over 500 cycles (1 A g −1 ) in SIBs. Moreover, they can deliver a capacity of 170.2 mA h g −1 after 150 cycles (0.1 A g −1 ) at 0°C. In addition, full cells based on FeV 2 S 4 @ GO@CNF anodes and Na 3 V 2 (PO 4 ) 3 /C cathodes achieve a remarkable capacity of 164 mA h g −1 after 100 cycles at 0.5 A g −1 . The high specific capacities and stability of FeV 2 S 4 @GO@CNF can be attributed to GO, which controls the size of FeV 2 S 4 nanoparticles and their distribution in CNFs, resulting in the enhanced stability of FeV 2 S 4 @GO@CNF. This study may provide a new strategy for the synthesis of nanoparticle-CNF composites in catalysts and batteries. 拥有高比容量的金属硫化物作为负极材料在钠离子电池 (SIBs)领域备受关注. FeV 2 S 4 作为一种典型的金属硫化物, 由于体积 变化大, 存在容量衰减快、稳定性差的问题. 本文利用氧化石墨烯 (GO)实现了对FeV 2 S 4 纳米粒子尺寸和分布的调控, 使其更好地包 裹在碳纳米纤维(CNFs)中, 从而制备了FeV 2 S 4 @GO@CNF. FeV 2 S 4 @GO@CNF负极与表面拥有更多粒子的FeV 2 S 4 @CNF负极相 比具有更优异的Na+存储性能. FeV 2 S 4 @GO@CNF用于钠离子电池 负极时, 200次循环(0.1 A g −1 )后容量仍然可保持在411 mA h g −1 , 500次循环(1 A g −1 )后可保持在227 mA h g−1 . 此外, 在0°C下, 经过 150次循环(0.1 A g −1 )后, 仍可以输出170.2 mA h g −1 的容量. 以FeV 2 S 4 @GO@CNF作为负极, Na 3 V 2 (PO 4 ) 3 /C作为正极的全电池在 0.5 A g −1 下循环100 次后, 其容量达到164 mA h g −1 . FeV 2 S 4 @GO@CNF表现出高比容量和稳定性, 这是由于GO控制了 FeV 2 S 4 的颗粒大小及其在CNFs中的分布, 从而提高了FeV 2 S 4 @ GO@CNF的稳定性. 本研究为纳米CNF复合材料的制备提供了新 思路. | Controllable deposition of FeV2S4 in carbon fibers for sodium-ion storage with high capacity and long lifetime | 10.1007/s40843-020-1542-8 |
2021-06-01 | Mid-infrared (IR) detectors based on the emerging low-dimensional (two-dimensional and quasi one-dimensional) materials offer unique characteristics including large bandgap tunability, optical polarization sensitivity and integrability with typical silicon process, which are not available in the mid-IR detectors based on traditional compound semiconductors. Here, we review the recent progress in study of mid-IR detectors based on the low-dimensional materials, including black phosphorus, black arsenic phosphorus, tellurene and BaTiS 3 , from the perspectives of crystal structure, material synthesis, optical properties, and the detector characteristics. The detector gain and detectivity are benchmarked, and the unique properties, such as the polarization sensitivity, are discussed. We also provide our perspective about key future research directions in this field. | Emerging low-dimensional materials for mid-infrared detection | 10.1007/s12274-020-3128-7 |
2021-06-01 | Composting is an environment-friendly method for recycling organic waste, and incorporation of heat and aeration can enhance favorable conditions for microbial growth in the process. This research aimed to evaluate the influence of the introduction of solar heat and aeration to the waste grass exposed to the composting process. The compost piles studied were subjected to different processes: application of solar-heated aeration, only-aeration, solar heating with a greenhouse, and control. Solar-heated air was introduced to a compost pile of grass clippings and compared with a greenhouse compost system. The composting process of 70 days was monitored for temperature, oxygen, moisture, organic matter loss, and humification rate. Germination index has been used to evaluate the maturation of the composts produced. The highest temperature was obtained at the compost pile with the greenhouse. This system reached the highest temperature (68.2 °C) on day 15; the ambient temperature on that day was 20.6 °C. The decreases in the C/N ratios after day 70 of composting were 20% and 15% for the greenhouse and the system where solar-heated air was introduced, respectively. Although the temperature of the solar-heated air was higher than that of the greenhouse, thermophilic temperature levels could not be reached in the aerated compost pile, which indicated a cooling effect of excessive aeration even with the heated air. Composting of grass clippings resulted in a decrease in organic matter content and enhancement in seed germination and root growth, obtaining high GI levels, inferring no phytotoxicity. This study showed that composting of grass clippings with low C/N ratios and high humidity can still be possible by using solar energy. Graphical abstract | Incorporation of solar-heated aeration and greenhouse in grass composting | 10.1007/s11356-021-12577-7 |
2021-06-01 | The development of an effective approach to improve low-temperature nitrification of domestic wastewater remains an important issue that needs to be urgently addressed. This study was intended to verify the feasibility of using iron scraps as an effective immobilization material to enhance nitrification activity in domestic wastewater-treatment systems at low temperatures. Iron scraps were tried and compared with one common immobilization material (PVA-SA embedded balls) in terms of low-temperature nitrification performances, anti-shock capacity, dynamics of microbial community, and economic costs. The results showed that compared with control, the average nitrification efficiency of iron scraps and PVA-SA embedded balls increased separately by 15.7% and 27.6% at low temperatures. Among these groups, the iron scrap-based group demonstrated the best anti-shock capacity and the smallest fluctuation (lower than 10%) with the shortening of HRT (hydraulic retention time) or the increase of inlet ammonium level. Nitrosomonas was found to be the dominant bacterial genera for these two immobilization materials. The increased costs of iron scraps and PVA-SA embedded balls were about ¥0.03 and ¥0.78 per ton of treated domestic wastewater. Taken together, iron scraps have some significant advantages including low costs, easy availability, and good anti-shock capacity, which make them a promising candidate for enhanced nitrification of domestic wastewater at low temperatures. | Feasibility of iron scraps for enhancing nitrification of domestic wastewater at low temperatures | 10.1007/s11356-021-12607-4 |
2021-06-01 | Long-term cycle life and high safety are important performances of lithium-ion power batteries. Voltage windows have a significant impact on battery cycle life and safety. While the mechanism by which an upper cut-off voltage affects the performances of lithium-ion batteries has been extensively studied, the effect of a lower cut-off voltage (LCV) on the cycle life and safety of lithium-ion batteries, especially nickel-rich layered oxide/graphite–SiO x batteries, is poorly understood. In this work, the as-prepared LiNi 0.8 Co 0.1 Mn 0.1 O 2 /graphite–SiO x pouch batteries have been cycled with different LCVs. When LCVs increase from 2.80 to 3.00 V, the capacity retention of the batteries increases from 90.66 to 93.98% in the 500 cycles, and the average temperature rise in discharging process decreases from 11.3 to 9.1 °C at the second stage. The resistance of batteries reduces because of the increase of LCVs, resulting in the decreased temperature rise and side reaction of the batteries. The increase of LCVs of batteries will be conducive to improving the cycle life and safety of batteries. This study provides a new direction for selecting voltage windows of batteries and a new idea for improving cycle and safety performances of batteries. | Effect of lower cut-off voltage on LiNi0.8Co0.1Mn0.1O2/graphite–SiOx pouch battery | 10.1007/s10008-021-04948-4 |
2021-06-01 | Utilization of low-grade manganese ore adopting the carbothermic reduction roasting process is a proven method to produce high-grade manganese ore. To minimize industrial waste and protect the environment, gas cleaning plant sludge (GCPS), which is a solid waste from steel industries, was employed as a reductant to perform the reduction roasting process. The optimum conditions to carry out reduction roasting of the low-grade manganese ore were found to be: a roasting temperature of 950 °C, a residence time of 2 h, 40% GCPS as reductant, and magnetic separation at 5000 G for a manganese ore size of –10 mm. A low-grade manganese ore comprising Mn grade 31.27% and Fe grade 19.78% having a Mn/Fe ratio of 1.58 containing a high silica content of 26.48% was used for the carbothermic reduction roasting having mineral phases of pyrolusite (MnO 2 ) and hematite (Fe 2 O 3 ) as found from XRD. The gangue minerals were separated during the magnetic separation, and the upgraded product was obtained, which reached a maximum value of TMn 49.5% with RMn 76.55% and TFe 62.19% with RFe 42.51%. In the study, activated charcoal (AC) was also taken as a reductant for comparative analysis; the experimental results revealed that GPCS performed better than that of the AC, showing potential to be used as a reductant in metallurgical industries. However, the resulted Mn/Fe ratio was very low for the reduced sample; therefore, it can be used for smelting along with high-grade manganese ores as a feed. | Sustainable Utilization of GCP Sludge as a Reductant in the Reduction Roasting of Low-Grade Manganese Ore to Recover Mn and Fe Values | 10.1007/s42461-021-00380-4 |
2021-06-01 | Abstract The effect of the thermal switching of a layered GeS:Nd single crystal is investigated in a wide range of temperatures ( T = 80–350 K). The effect of γ irradiation on the thermal switching of a GeS:Nd single crystal is studied at different doses (30 and 100 krad). It is found that no thermal-switching effect is observed in the GeS:Nd crystal after γ irradiation at low doses with the formation of an ordered structure. When the γ irradiation increases to 100 krad, structure degradation is observed, as a result of which the crystal loses its photosensitivity, and no thermal-switching effect is detected. | Effect of Gamma Irradiation on the Thermal Switching of a GeS:Nd Single Crystal | 10.1134/S1063782621070034 |
2021-06-01 | The climate is a complex, chaotic system with many degrees of freedom. Attaining a deeper level of understanding of climate dynamics is an urgent scientific challenge, given the evolving climate crisis. In statistical physics, many-particle systems are studied using Large Deviation Theory (LDT). A great potential exists for applying LDT to problems in geophysical fluid dynamics and climate science. In particular, LDT allows for understanding the properties of persistent deviations of climatic fields from long-term averages and for associating them to low-frequency, large-scale patterns. Additionally, LDT can be used in conjunction with rare event algorithms to explore rarely visited regions of the phase space. These applications are of key importance to improve our understanding of high-impact weather and climate events. Furthermore, LDT provides tools for evaluating the probability of noise-induced transitions between metastable climate states. This is, in turn, essential for understanding the global stability properties of the system. The goal of this review is manifold. First, we provide an introduction to LDT. We then present the existing literature. Finally, we propose possible lines of future investigations. We hope that this paper will prepare the ground for studies applying LDT to solve problems encountered in climate science and geophysical fluid dynamics. | Applications of large deviation theory in geophysical fluid dynamics and climate science | 10.1007/s40766-021-00020-z |
2021-06-01 | Pollution of industrial wastewaters containing dyes is a major concern for health in many countries, calling for advanced remediation techniques. Here, we review dye classification, toxicity, and removal with focus on adsorption using nanomaterials and magnetic nanoparticles. We present isotherm modeling and kinetic studies. We discuss factors controlling dye adsorption, such as pH, dye concentration, adsorbent amount, and temperature. Adsorption using magnetic nanoparticles appear as a simple and cost-effective technique. Removal efficiency increases with adsorbent concentration but declines sharply with increasing pH. Temperature is also highly influencing the removal. | Magnetite nanoparticles as sorbents for dye removal: a review | 10.1007/s10311-020-01173-9 |
2021-06-01 | Brewers’ spent grains (BSG) make up to 85% of a brewery’s solid waste, and is either sent to landfill or sold as cheap animal feed supplement. Xylo-oligosaccharides (XOS) obtained from BSG are antioxidants and prebiotics that can be used in food formulations as low-calorie sweeteners and texturisers. The effect of extremely low acid (ELA) catalysis in liquid hot water (LHW) hydrothermal treatment (HTT) was assessed using BSG with dry matter contents of 15% and 25%, achieved by dewatering using a screw press. Batch experiments at low acid loadings of 5, 12.5 and 20 mg/g dry mass and temperatures of 120, 150 and 170 °C significantly affected XOS yield at both levels of dry mass considered. Maximum XOS yields of 76.4% (16.6 g/l) and 65.5% (31.7 g/l) were achieved from raw BSG and screw pressed BSG respectively, both at 170 °C and using 5 mg acid/g dry mass, after 15 min and 5 min, respectively. These XOS yields were obtained with BSG containing up to 63% less water and temperatures more than 20 °C lower than that reported previously. The finding confirms that ELA dosing in LHW HTT allows lowering of the required temperature that can result in a reduction of degradation products, which is especially relevant under high solid conditions. This substantial XOS production intensification through higher solid loadings in HTT not only achieved high product yield, but also provided benefits such as increased product concentrations and decreased process heat requirements. | Intensification of Xylo-oligosaccharides Production by Hydrothermal Treatment of Brewer’s Spent Grains: The Use of Extremely Low Acid Catalyst for Reduction of Degradation Products Associated with High Solid Loading | 10.1007/s12010-021-03525-9 |
2021-06-01 | Key Message Chilling injury resulted in tree water-use changes in mangrove forests, with two Sonneratia species displaying different severities of impact and recovery patterns. Abstract Mangroves are periodically influenced in negative ways by non-freezing temperatures across their global sub-tropical range. However, physiological and morphological evidence of chilling influences to non-freezing chilling events has not been measured in field settings. In this study, we measured sap flow ( J s ) during such a chilling (but non-freezing) event in southern China and documented the reductions in J s and the recovery that ensued. We calculated tree water use (TWU) from J s measurements taken from thermal dissipation sap flow sensors on two mangrove species ( Sonneratia apetala and S. caseolaris ). This chilling event significantly injured the mangrove trees in the form of leaf scorch and massive defoliation. Diurnal variations of stem J s of both species were altered significantly after chilling. On the day of the chilling event, J s of S. caseolaris was reduced from the daily maximum of 44.1 g H 2 O m −2 s −1 to 0 immediately after chilling, which lasted throughout the remainder of the day. In contrast, S. apetala showed a certain low-temperature tolerance, while still maintaining an adequate transpiration rate after chilling, indicative of a more resilient hydraulic transport system to low temperatures. The sap flow data collected revealed substantial evidence for acute water conservation during low-temperature events, perhaps ameliorating low-temperature damage. Hence, the responses of some mangrove species with high sensitivity to low, but non-freezing, temperature (such as S. caseolaris ) may indicate that mangroves possess adaptive whole-tree strategies to cold temperature. | Sap flow evidence of chilling injury and recovery in mangroves following a spring cold spell | 10.1007/s00468-021-02089-9 |
2021-06-01 | Maize is a subtropical, cold-sensitive species. However, some varieties of this species have the potential to withstand long-term low temperatures, even at the seedling stage. The molecular basis of this phenomenon has not been determined. In a chromatin-level study, we compared the cold-stress reaction of seedlings of two maize inbred lines showing contrasting levels of cold sensitivity. The cold-tolerant line was selected based on field data and previous physiological and transcriptomic level studies. The first condition of gene expression—chromatin accessibility—was assessed by formaldehyde-aided isolation of regulatory elements method and DNA sequencing. Potentially expressed genes and cis -regulatory sequences open for interaction with transcription factors have been defined. The results of this study suggest that during cold stress, the tolerant maize line shifted resources from growth to defense. This shift was shown by potential hormone-level events—degradation of growth-promoting gibberellins and synthesis of jasmonic and abscisic acids. This finding is congruent with the xeromorphic morphology of seedlings of the cold-tolerant line and their ability to regrow when stress ceases. It is a common reaction of cold-tolerant maize lines. Moreover, in the cold-tolerant line, several genes from the low-temperature signaling pathways were potentially expressed. Additionally, numerous stress-response AP2/EREBP-binding cis -motifs were accessible in the cold-tolerant line. Differently in the cold-sensitive B73 line, MADS-binding cis -motifs were the most abundant. Development of the photosynthetic apparatus is crucial for the survival of maize seedlings at low temperature. Our results suggest efficient photosynthesis in seedlings of the cold-tolerant line, as was described earlier in physiological-level analyses. | Chromatin-Level Differences Elucidate Potential Determinants of Contrasting Levels of Cold Sensitivity in Maize Lines | 10.1007/s11105-020-01254-7 |
2021-06-01 | Lead extrusion dampers are supplemental energy-dissipation devices that are used to mitigate seismic structural damage. Small volumetric sizes and high force capacities define high-force-to-volume (HF2V) devices, which can absorb significant response energy without sacrificial damage. However, the design of such devices for specific force capacities has proven difficult based on the complexities of their internal reaction mechanisms, leading to the adoption of empirical approaches. This study developed upper- and lower-bound force capacity estimates from analytical mechanics based on direct and indirect metal extrusion for guiding design. The derived equations are strictly functions of HF2V device geometric parameters, lead material properties, and extrusion mechanics. The upper-bound estimates from direct and indirect extrusion are denoted as ( F UB,1 , F UB,2 ) and ( F UB,3 , F UB,4 ), respectively, and the lower-bound estimates are denoted as ( F LB , F LB,1 ) based on the combination of extrusion and friction forces. The proposed models were validated by comparing the predicted bounds to experimental force capacity data from 15 experimental HF2V device tests. The experimental device forces all lie above the lower-bound estimates ( F LB , F LB,1 ) and below the upper-bound estimates ( F UB,1 , F UB,2 , F UB,4 ). Overall, the ( F LB , F UB,2 ) pair provides wider bounds and the ( F LB,1 , F UB,4 / F UB,1 ) pair provides narrower bounds. The ( F LB,1 , F UB,1 ) pair has a mean lower-bound gap of 36%, meaning the lower bound was 74% of the actual device force on average. The mean upper-bound gap was 33%. The bulge area and cylinder diameter of HF2V devices are key parameters affecting device forces. These relatively tight bounds provide useful mechanics-based predictive design guides for ensuring that device forces are within the targeted design range after manufacturing. | Modeling limit force capacities of high force to volume lead extrusion dampers | 10.1007/s11709-021-0724-x |
2021-06-01 | Abstract The heat treatable aluminium alloy AA2219 is subjected to mechanical stress relieving by way of cold deformation after solution treatment to relieve the quenched in stresses as thermal stress relieving is not possible due to the requirement of higher temperature than the ageing temperature. Cold deformation prior to aging has also been found to yield improved strength. Though this phenomenon is to some extent being exploited in aluminium alloy AA2219 sheets and plates, there is no experimental data available to understand the influence of cold compression on the extent of benefits obtainable on mechanical properties in forgings. In the present study to identify a thermo-mechanical treatment that can yield the maximum tensile strength, solution treated AA2219 forgings were subjected to cold deformation ranging from 0 to 25% and then artificially aged. The results indicates that the maximum room temperature tensile strength (both UTS and 0.2% PS) can be obtained at 10% post solution treatment cold deformation. As this alloy is being used for low temperature applications, it is very essential to assess the effect of higher cold compression on the low temperature (77 K) properties and the results show that the 77 K tensile properties more or less same beyond 2% cold deformation. As the weld properties are around 50% of the parent metal properties, any increase in the mechanical properties, is considered to be very crucial and very much needed for this alloy in the absence of aluminium–lithium alloy technology. Hence this study indicate that there is a good scope to increase the amount of cold compression after Solution treatment instead of restricting the same to 2%–5% maximum. Graphic Abstract | Influence of Thermomechanical Treatments on the Microstructure and Mechanical Properties of Aluminium Alloy AA2219 Hand Forgings | 10.1007/s12540-019-00557-z |
2021-06-01 | Monoclinic SrAl 2 Si 2 O 8 ceramics for Sr immobilization were prepared by a liquid-phase sintering method. The sintering temperature, mineral phase composition, microstructure, flexural strength, bulk density, and Sr ion leaching characteristics of the SrAl 2 Si 2 O 8 ceramics were investigated. A crystalline monoclinic SrAl 2 Si 2 O 8 phase formed through liquid-phase sintering at 1223 K. The introduction of four flux agents (B 2 O 3 , CaO·2B 2 O 3 , SrO·2B 2 O 3 , and BaO·2B 2 O 3 ) to the SrAl 2 Si 2 O 8 ceramics not only reduced the densification temperature and decreased the volatilization of Sr during high-temperature sintering but also impacted the mechanical properties of the ceramics. Product consistency tests showed that the leaching concentration of Sr ions in the sample with flux agent B 2 O 3 was the lowest, whereas that of Sr ions in the sample with flux agent BaO·2B 2 O 3 was the highest. These results show that the leaching concentration of Sr ions depends largely on the amorphous phase in the ceramics. Meanwhile, the formation of mineral analog ceramics containing Sr is an important factor to improve Sr immobilization. | Sintering of monoclinic SrAl2Si2O8 ceramics and their Sr immobilization | 10.1007/s12613-020-2056-6 |
2021-06-01 | We investigate a model of interacting Dirac fermions in 2 + 1 dimensions with M flavors and N colors having the U( M ) × SU( N ) symmetry. In the large- N limit, we find that the U( M ) symmetry is spontaneously broken in a variety of ways. In the vacuum, when the parity-breaking flavor-singlet mass is varied, the ground state undergoes a sequence of M first-order phase transitions, experiencing M + 1 phases characterized by symmetry breaking U( M ) → U( M − k ) × U( k ) with k ∈ {0 , 1 , 2 , · · · , M }, bearing a close resemblance to the vacuum structure of three-dimensional QCD. At finite temperature and chemical potential, a rich phase diagram with first and second-order phase transitions and tricritical points is observed. Also exotic phases with spontaneous symmetry breaking of the form as U(3) → U(1) 3 , U(4) → U(2) × U(1) 2 , and U(5) → U(2) 2 × U(1) exist. For a large flavor-singlet mass, the increase of the chemical potential μ brings about M consecutive first-order transitions that separate the low- μ phase diagram with vanishing fermion density from the high- μ region with a high fermion density. | Cascade of phase transitions in a planar Dirac material | 10.1007/JHEP06(2021)015 |
2021-06-01 | Abstract An ultrafine-grained (UFG) structure of equiaxed and fiber types in the low-carbon structural steel 05G2MFBT (Fe–2Mn–Mo–V–Nb–Ti) has been formed with various techniques of deformation-heat treatment. This steel with a UFG structure has been found to exhibit higher strength properties. Different deformation techniques have been shown to produce either a fibrous or an equiaxed UFG structure with carbide particles of a wide range of sizes. The brittle fracture resistance of the fibrous UFG steel has been found to be higher than that of the fine-grained steel after controlled rolling and subsequent accelerated cooling. Standard bending-impact tests have shown that the steel with a fibrous UFG structure is characterized by higher impact strength characteristics and a lower ductile–brittle transition temperature. | Effect of Deformation-Thermal Processing on the Microstructure and Mechanical Properties of Low-Carbon Structural Steel | 10.1134/S0031918X21060090 |
2021-06-01 | Maize, a C 4 sub-tropical crop, possesses higher temperature optima as compared to the C 3 plants. Low temperature (LT) stress confines the growth and productivity of maize. In this context, two maize genotypes, LT tolerant Gurez local and LT susceptible Gujarat-Maize-6 (G-M-6) were analysed in present study for various osmolytes and gene expression of antioxidant enzymes including Ascorbate–glutathione (AsA-GSH) besides trehalose biosynthetic pathways. With the progressive LT treatment, Gurez local showed lesser accumulation of stress markers like hydrogen peroxide (H 2 O 2 ) and malondialdehyde, a significant increase in osmoprotectants like free proline, total protein, total soluble sugars, trehalose, total phenolics and glycine betaine, and a significant reduction in the plant pigments as compared to the G-M-6. Additionally, Gurez local was found to possess a well-established antioxidant defense system as revealed from the elevated transcripts and enzyme activities of various enzymes of AsA-GSH pathway. Higher gene expression and enzyme activities were exhibited by superoxide dismutase, catalase and peroxidase besides the gene expression of trehalose biosynthetic pathway enzymes. Moreover, through principal component analyses, a positive correlation of all analysed parameters with the LT tolerance was noticed in Gurez local alone demarcating the genotypes on the basis of their extent of LT tolerance. Overall, the present study forms the basis for unravelling of LT tolerance mechanisms and improvement in the performance of the temperate maize. | Low temperature elicits differential biochemical and antioxidant responses in maize (Zea mays) genotypes with different susceptibility to low temperature stress | 10.1007/s12298-021-01020-3 |
2021-06-01 | Increased blood pressure (BP) caused by exposure to cold temperatures can partially explain the increased incidence of cardiovascular events in winter. However, the physiological mechanisms involved in cold-induced high BP are not well established. Many studies have focused on physiological responses to severe cold exposure. In this study, we aimed to perform a comprehensive analysis of cardiovascular autonomic function and sleep patterns in rats during exposure to mild cold, a condition relevant to humans in subtropical areas, to clarify the physiological mechanisms underlying mild cold-induced hypertension. BP, electroencephalography, electromyography, electrocardiography, and core body temperature were continuously recorded in normotensive Wistar-Kyoto rats over 24 h. All rats were housed in thermoregulated chambers at ambient temperatures of 23, 18, and 15 °C in a randomized crossover design. These 24-h physiological recordings either with or without sleep scoring showed that compared with the control temperature of 23 °C, the lower ambient temperatures of 18 and 15 °C not only increased BP, vascular sympathetic activity, and heart rate but also decreased overall autonomic activity, parasympathetic activity, and baroreflex sensitivity in rats. In addition, cold exposure reduced the delta power percentage and increased the incidence of interruptions during sleep. Moreover, a correlation analysis revealed that all of these cold-induced autonomic dysregulation and sleep problems were associated with elevation of BP. In conclusion, mild cold exposure elicits autonomic dysregulation and poor sleep quality, causing BP elevation, which may have critical implications for cold-related cardiovascular events. | Roles of cardiovascular autonomic regulation and sleep patterns in high blood pressure induced by mild cold exposure in rats | 10.1038/s41440-021-00619-z |
2021-06-01 | The Carleton University Brayton Cycle Loop (CUBCL) is a project involving virtually all aspects of 10 MW supercritical CO 2 gas turbine design. One of the concerns regarding the 10 MW S-CO 2 gas turbine is recuperators degradation due to fouling. This work reveals that when the high temperature recuperator (HTR) overall heat transfer coefficient declines from 2471.65 to 1882.83 (kW/m 2 K), the cold outer temperature decreases from 814.16 to 728.89 K. To offset this, the control system directs the primary heat exchanger to add 11101.14 kW of heat to compensate for the loss due to fouling, which results in a cycle efficiency decrease from 48.25 to 32.16%. The amount of heat added by the primary heat exchanger will not be absorbed in the HTR and/or the low temperature recuperator (LTR) due to fouling layers, so the LTR hot stream discharge temperature (recompressor inlet) rises. The current design of a 10 MW S-CO 2 gas turbine recompressor works on fluid before heat is removed by the pre-cooler. This highlights the necessity for further protection to prevent the recompressor from overheating. | Investigation of the Fouling Effect of Recuperators on the Recompressor and Cycle Efficiency of a 10 MW S-CO2 Gas Turbine Power Plant | 10.1007/s11668-021-01157-z |
2021-06-01 | Atomic oxygen (AO) is a major threat to satellites in Low Earth Orbits (LEO). AO causes serious damage to satellites such as erosion, corrosion and damage to almost all satellites surfaces. This study presents numerical prediction for the space environment effects on NARSSCube satellite using ATOMOX module in Space ENVironment Information System (SPENVIS) online simulation tools. Indeed, the prediction of erosion yields of NARSSCube structure induced by AO flux in LEO with different models is calculated. NRLMSISE model shows the highest mass and thickness loss for the outer surfaces of the satellite in all worst-case scenarios. A comparative study, for the erosion yields of some materials using SPENVIS, MISSE2 and other calculations, is presented. This research recommends the necessity of developing a database for all materials used in space providing all data for the effect of AO on each material in addition to the erosion depth and mass loss. | Effect of Atomic Oxygen on LEO CubeSat | 10.1007/s42405-020-00336-w |
2021-06-01 | The nanocomposite of bead necklace-like structure in which single stands of single-walled carbon nanotube (SWCNT) are impregnated in several polypyrrole (PPy)/phenylalanine (PA), PPy@PA, nanoparticles, with an average bead diameter of 80 nm and SWCNT length of 5 µm, as a sensing material for detecting ammonia gas, was synthesized by simple emulsion polymerization. The synthesized nanocomposite showed an electrical conductivity more than 5 times higher than that of PPy alone with a selective reactivity to ammonia gas. In addition, it exhibited a high sensitivity of less than 100 ppb at room temperature and was not significantly affected by the sensitivity even under the humidity conditions of 0 ∼70% RH (relative humidity). | Bead Necklace-Shaped Single Walled Carbon Nanotube-Polypyrrole Nanocomposites for Ammonia Gas Sensor | 10.1007/s13233-021-9049-9 |
2021-06-01 | Alloying can make conventional metals reach ultra-high strength, but this usually comes at dramatic loss of toughness. In this work, a desirable strength–toughness combination in high-strength low-alloy steel achieved via trace carbon addition. The significance of carbon in tailoring variant pairing and tuning impact toughness was elucidated from the perspective of crystallography and thermodynamics. As the carbon content increases, the packets and blocks are refined, and the − 40 ℃ impact toughness improves. The enhancement of impact toughness results from the higher density of block boundaries, and the fracture mode shifts from brittle fracture to ductile–brittle combined fractures, then to ductile fracture due to the increased carbon. Increasing the carbon content would lower the martensite start temperature ( M S ) temperature and driving force for martensitic transformation, and increase the strength of austenite matrix, which in turn contributes to producing more V1/V2 variant pairs to accommodate the transformation strain. | Tailoring Variant Pairing to Enhance Impact Toughness in High-Strength Low-Alloy Steels via Trace Carbon Addition | 10.1007/s40195-020-01186-x |
2021-06-01 | Doing experiments in order to determine mechanical properties of nanocomposites costs a lot. Therefore, finding the ways by which the properties of the nanocomposites can be predicted without any empirical or few number of empirical experiments seems to be useful. In the present study, efforts have been made to create a relation between mathematical model based on dimensionless number (Ch) and mechanical properties of low-density polyethylene/linear low-density polyethylene/styrene ethylene butadiene styrene (LDPE/LLDPE/SEBS) nanocomposite reinforced by nanoparticles of calcium carbonate. The proposed model is able to predict mechanical properties of nanocomposites based on their composition. This model is capable to predict elongation at break in terms of Young’s modulus and fracture toughness, and to predict fracture toughness in terms of Young’s modulus and elongation at break. The results showed prediction of the dimensionless number Ch model, and the experimental results are consistent. | Estimation of mechanical properties of LDPE/LLDPE/SEBS nanocomposite reinforced with calcium carbonate nanoparticles by Ch mathematical model | 10.1007/s10973-021-10653-1 |
2021-06-01 | In recent years, potassium-ion batteries(KIBs)have received a lot of attention for their high energy density and low cost. However, a suitable anode is currently lacking. In this paper, to explore potential anode materials, PC 3 monolayer was predicted using first-principles. The calculation results show that the PC 3 monolayer is stiff and conductive after adsorbed K atoms. The adsorbed K atoms have small migration energy of 0.09 eV which provides a good charge/discharge rate. And the KIBs with PC 3 monolayer anode shows high capacity (1200 mAh g −1 ) and low open-circuit voltage (OCV) (0.11 V) offering high energy density. At a maximum capacity of 1200 mAh g −1 , the PC 3 monolayer shows only small deformation and volume changes. The results predict PC 3 monolayer would make a good material selection for potassium battery anodes. | Theory prediction of PC3 monolayer as a promising anode material in potassium-ion batteries | 10.1007/s11581-021-03994-2 |
2021-06-01 | Subsurface samples of the Talhar shale, Lower Goru Formation, are analyzed for smectite (montmorillonite) and illite in the Nur-dep#1 (ND‒1), well 2, Southern Lower Indus Basin, Pakistan. The ND‒1, well 2 is an unsuccessful well drilled by the OGDCL, Pakistan, for the shale gas exploration. Illitization and elemental content constrained using XRD qualitative and XRF quantitative analyses, respectively. The illite content increases from 15 to 55% with increasing depth. The fine-grained shale comprises chlorite, kaolinite, halloysite, allophane, muscovite, microcline, illite and montmorillonite. Chlorite was observed at 3450–3452 m, whereas kaolinite is present at depth range of 3450–3482 m. The mix layer expandability decreases from 40 to 20% at depth ranges from 3450 to 3552 m, respectively. The interstratification is random to ordered. Potassium and silicon contents with respect to aluminum and calcium are increasing with depth. Data obtained in this research indicate that the shale gas is immature and the oil is an early–medium stage of maturation. | Smectite illitization of the Talhar shale, Lower Goru Formation, Southern Indus Basin, Pakistan | 10.1007/s13202-021-01183-5 |
2021-06-01 | Purpose Light-induced fluorescence was evaluated as a process analytical tool in the development of quantitative models for the monitoring of a low-dose formulation manufacturing process. Method The system, equipped with a probe, was positioned in a tablet press feed-frame to monitor the active pharmaceutical ingredient content of the flowing powder before compression. Results Modeling errors of 1.1% and lower in cross-validation for a 0.67% w/w drug load were observed, which is remarkable for a process analytical tool. Conclusions While light-induced fluorescence is emerging as a promising technology, robustness improvements and demonstration of method validation are still required. The technology is expected to become a tool of choice, ready for manufacturing deployment, to support the monitoring and potentially control of low-dose pharmaceutical formulations. | Feasibility of Using Light-Induced Fluorescence Spectroscopy for Low-Dose Formulations Monitoring and Control | 10.1007/s12247-020-09432-6 |
2021-06-01 | Compared with the thin plate production process, the behavior of NbC precipitating would be different in thicker plate from the rolling processing due to reduction ratio conditions. The mechanism of epitaxial growth of NbC precipitating along with TiN particles was observed. The distribution of TiN particles, which influenced by N content in steels, would determine the distribution of the combined TiN + NbC particles by transmission electron microscopy. TiN particle is a high-temperature precipitate. The TiN particle is precipitated completely before the NbC particle is precipitated. It is concluded that the distribution of TiN was most important factor to control austenite grain size by Zener drag force. When the N content was higher in the steel would result in the coarser TiN particles which are harmful to controlling the size in roughing. Increasing of N content did not lead to an increase in the Zener drag force to control austenite grain size. | Analysis of Precipitation of NbC in Low Reduction Ratio Conditions | 10.1007/s13632-021-00749-3 |
2021-06-01 | Abstract The processes of formation of superhard coatings by treating titanium films on sapphire substrates with a low-temperature nitrogen plasma flow in open atmosphere have been studied. It is shown that a coating of nitrogen-containing TiO 2 with a rutile structure, the microhardness of which is twice as high as that of rutile TiO 2 (up to 27 GPa), is formed during plasma treatment. Deposition of this coating hardens the surface of sapphire plates by 22–23%. High yield and synthesis in open atmosphere make the proposed technique promising for preparing superhard coatings with a high oxygen resistance. | Formation of Superhard Coatings during Treatment of Titanium Films with Low-Temperature Nitrogen Plasma in Open Atmosphere | 10.1134/S1063785021050072 |
2021-06-01 | Studying on the pore size distribution of coal is vital for determining reasonable coalbed methane development strategies. The coalbed methane project is in progress in the southern Junggar Basin of northwestern China, where high volatile bituminous coal is reserved. In this study, with the purpose of accurately characterizing the full-scale pore size distribution of the high volatile bituminous coal of the southern Junggar Basin, two grouped coal samples were applied for mercury intrusion porosimetry, low-temperature nitrogen adsorption, low-field nuclear magnetic resonance, rate-controlled mercury penetration, scanning electron microscopy, and nano-CT measurements. A comprehensive pore size distribution was proposed by combining the corrected mercury intrusion porosimetry data and low-temperature nitrogen adsorption data. The relationship between transverse relaxation time ( T 2 , ms) and the pore diameter was determined by comparing the T 2 spectrum with the comprehensive pore size distribution. The macro-pore and throat size distributions derived from nano-CT and rate-controlled mercury penetration were distinguishingly analyzed. The results showed that: 1) comprehensive pore size distribution analysis can be regarded as an accurate method to characterize the pore size distribution of high volatile bituminous coal; 2) for the high volatile bituminous coal of the southern Junggar Basin, the meso-pore volume was the greatest, followed by the transition pore volume or macro-pore volume, and the micro-pore volume was the lowest; 3) the relationship between T 2 and the pore diameter varied for different samples, even for samples with close maturities; 4) the throat size distribution derived from nano-CT was close to that derived from rate-controlled mercury penetration, while the macro-pore size distributions derived from those two methods were very different. This work can deepen the knowledge of the pore size distribution characterization techniques of coal and provide new insight for accurate pore size distribution characterization of high volatile bituminous coal. | Pore size distribution of high volatile bituminous coal of the southern Junggar Basin: a full-scale characterization applying multiple methods | 10.1007/s11707-020-0845-x |
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