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2023-07-01 | Quasi-zero stiffness (QZS) device is widely studied for their better performance in low-frequency and micro-vibration isolation due to the high-static and low-dynamic (HSLD) stiffness characteristics. The previous QZS isolator with determined parameters is not suitable for variable isolated mass. In this study, a novel compound regulative quasi-zero stiffness air spring (CRQSAS) has been proposed and designed by introducing a bidirectional regulator for the horizontal air springs. The CRQSAS could change the quasi-zero region depending on the payload. To identify the parameters of the convoluted air spring (CAS) and novel rubber air spring (NRAS), the air spring testing system is established. The stiffness functions of air springs are obtained by the multi-parameter fitting method. According to the structure of the CRQSAS, the dynamic model of the system is analyzed and simplified by Taylor Expansion. The harmonic balance method (HBM) is applied to calculate the frequency response and absolute displacement transmissibility. An experimental prototype has been set up to verify the theoretical model and simulation. Compared with the single NRAS, CRQSAS performs better in low-frequency and micro-amplitude vibration. The research proves that CRQSAS is a passive device widely applied for improving isolation precision under low-frequency vibration. | Dynamic frequency response characteristics of a compound regulative quasi-zero stiffness air spring system | 10.1007/s11431-022-2268-2 |
2023-07-01 | Retinol is widely used for topical application for antiaging. However, the efficacy and effect rate of different concentrations of retinol have been rarely analyzed. Therefore, in this study, the efficacy and rate of effect of retinol concentrations from 1500 to 6600 IU, on various skin parameters, have been compared. Seventy-two Korean women aged 40–59 years participated in this study. Retinol was used by them for 24 weeks; the effects were measured at 0, 2, 4, 8, 12, and 24 weeks. The measurement parameters for aging were crow’s feet, forehead wrinkles, nasolabial fold, dermal density, and elasticity and that for skin color were skin brightness, yellowness, redness, and standard deviation of skin brightness. The texture of the skin was measured by measuring the skin roughness and pores, and the skin barrier function was evaluated through hydration, sebum, and desquamation. Low concentration retinol (1500–2500 IU) had a significantly higher effect in skin color, brightness, and elasticity and faster improvement rate in skin brightness and elasticity compared to that for high concentration (3300–6600 IU). High concentration of retinol had a significantly higher effect in wrinkles, dermal density and pores and faster improvement rate for wrinkles, skin texture, pores, and desquamation compared to that for low concentration. This study evaluated the changes caused by different concentration of retinol over a long period of time. The results of this study have great implications as the optimal concentration of retinol can be prescribed for an accurate period for the desired results without side effects. | A long term study of the difference in efficacy and effect rate of various concentrations of retinol (1500–6600 IU) in middle aged women | 10.1007/s00403-022-02520-2 |
2023-06-30 | Several low-cost adsorbents, including orange mesocarp (OMS), Bengal gram husk (BGH), and Khangar, were investigated for their capability to absorb chromium hexavalent ions from synthetic solutions. Process parameters like pH, dose of the adsorbent, concentration of metal ions, and the time they remain in contact were used to calculate the equilibrium adsorption levels. The most crucial factor for removing Cr(VI) ions was observed to be pH. The highest removal for Cr(VI) was determined to be 87%, 90%, and 92%, for OMS, BGH, and Khangar adsorbents respectively. Langmuir adsorption isotherm was observed to be the best fitted, with regression values ( R 2 ) of 0.988, 0.974, and 0.989 for OMS, BGH, and Khangar, separately. The kinetic study of Cr(VI) was best expressed with pseudo-second-order. Adsorption process was found to be endothermic and spontaneous in nature with enthalpy (ΔH 0 ) of 48.74, 52.54, and 53.68 KJ mol −1 and entropy of 48.95, 52.78, and 53.93 KJ K −1 mol −1 for OMS, BGH, and Khangar respectively. Also, the possible use of OMS, BGH, and Khangar for Cr(VI) ion removal is indicated by the possibility of reusing adsorbents successfully up to three times. According to the study out of the three adsorbents, Khangar was observed to be the most efficient adsorbent for extracting Cr(VI) ions from an aqueous medium. | Effective removal of Cr(VI) ions from aqueous solution using low-cost adsorbents (orange mesocarp, Bengal gram husk, and Khangar): equilibrium, kinetic, and thermodynamic study | 10.1007/s13399-023-04473-6 |
2023-06-30 | The incidence of melanoma is continuously increasing over time. Melanoma is the most aggressive skin cancer, significantly reducing quality of life and survival rates of patients at advanced stages. Therefore, early diagnosis remains the key to change the prognosis of patients with melanoma. In this context, advanced technologies are under evaluation to increase the accuracy of the diagnostic, to better characterize the lesions and visualize their possible invasiveness in the epidermis. Among the innovative methods, because melanin is paramagnetic, clinical low frequency electron paramagnetic resonance (EPR) that characterizes the melanin content in the lesion has the potential to be an adjunct diagnostic method of melanoma. In this review, we first summarize the challenges faced by dermatologists and oncologists in melanoma diagnostic and management. We also provide a historical perspective on melanin detection with a focus on EPR spectroscopy/imaging of melanomas. We describe key elements that allow EPR to move from in vitro studies to in vivo and finally to patients for melanoma studies. Finally, we provide a critical view on challenges to meet to make EPR operational in the clinic to characterize pigmented lesions. | Towards Characterization of Skin Melanoma in the Clinic by Electron Paramagnetic Resonance (EPR) Spectroscopy and Imaging of Melanin | 10.1007/s11307-023-01836-3 |
2023-06-29 | Commercial office buildings are major electrical energy guzzlers as they are required to maintain high levels of overall occupant comfort to maximize workers’ productivity. Thermal comfort, visual comfort, and noise insulation are three major aspects of overall comfort in such buildings. There is ample potential to achieve these aspects of comfort through the passive design of the envelope and reduce the dependence on supplementary systems through building simulation optimization methodologies. But due to multiple conflicting objectives and complexity, these methodologies are seldom adopted by designers in early-stage design, especially in the Indian tropical subcontinent. The present study aims to provide ready-to-use guidelines in the form of recommended parameters for building envelope design of low-rise commercial buildings which after implementation will enhance the thermal, visual, and noise insulation performance of the building envelope in tropical climatic regions. Recommended material and thickness for construction layers of the exterior wall, roof, and glazing were formulated as guidelines for the different major climatic zones of the Indian tropical climate. | Development of design guidelines for thermal, visual, and noise insulation performance of building envelope of low-rise commercial office buildings in the Indian tropical climate | 10.1007/s12046-023-02191-3 |
2023-06-29 | In this work, the microstructure, and mechanical properties of cold-rolled low-density multi-principal-element Fe-30Mn-10Al-1.57C-2.3Cr-0.3Si-0.6Ti (wt.%) specimens were systematically investigated by annealing under different conditions. The microstructural evolution and strengthening mechanism were also examined. Results from x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron backscatter diffraction (EBSD) analyses confirmed that carbides were composed of TiC and κ -carbides. As the annealing temperature increased, both the volume fraction of κ -carbides and yield strength (YS) of the alloys decreased. TEM images indicated a pile-up of dislocations around carbides and boundary of twins. The increase in annealing temperature to 450 °C led to best mechanical properties of specimens with σ 0.2% = 1270.28 MPa, R m = 1318.67 MPa, and ε = 19.47%. Moreover, YS decreased by 9.28% and TE increased by 192.78%. Notably, the density of the as-obtained alloy reached 6.58 g/cm 3 , a value 15.6% lower than that of conventional steel. In sum, these findings are promising for future applications of low-density alloys. | Effect of Annealing on Microstructure and Mechanical Behavior of Cold Deformed Low-Density Multi-principal-Element High-Strength Alloys | 10.1007/s11665-023-08465-5 |
2023-06-29 | This study focuses on hydrothermal alteration in the geothermal reservoir of Cerro Pabellón (Andean Cordillera, Northern Chile). It is based on CP2A and CP5A production wells drilled above a local normal fault and presenting unlike hydraulic properties. Cuttings from 300 to 1555 m depth were sampled and analyzed using X-ray diffraction (XRD) to observe distribution of hydrothermal minerals and crystal chemistry variations of clays (fraction < 5 μm). Then, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM–EDX) allowed to perform microanalysis of hydrothermal minerals. These results highlight a mineral assemblage that was not observed before, composed of adularia + Ba-rich feldspar + feathery quartz + chalcedony + calcium arsenates + illite. They are characteristics of high-temperature hydrothermal alteration in epithermal settings and are restricted to shallow permeable fracture zones of the active part of the reservoir. Another fracture-controlled event related to a typical illitization is observed in all permeable fracture and fault zones of the geothermal system. This multi-event alteration seems strongly controlled by the eastern graben fault and the associated interconnected fracture network. | Structural control of the graben fault on hydrothermal alteration in the Cerro Pabellón geothermal system (Andean Cordillera, Northern Chile) | 10.1186/s40517-023-00260-8 |
2023-06-29 | Background Veterinary diagnostics aid intervention strategies, track zoonoses, and direct selective breeding programs in livestock. In ruminants, gastrointestinal nematode (GIN) parasites are a major cause of production losses, but morphologically similar species limit our understanding of how specific GIN co-infections impact health in resource-limited settings. To estimate the presence and relative abundance of GINs and other helminths at the species level, we sought to develop a low-cost and low-resource molecular toolkit applied to goats from rural Malawi smallholdings. Methods Goats were subjected to health scoring and faecal sampling on smallholdings in Lilongwe district, Malawi. Infection intensities were estimated by faecal nematode egg counts with a faecal subsample desiccated for DNA analysis. Two DNA extraction methods were tested (low-resource magbead kit vs high-resource spin-column kit), with resulting DNA screened by endpoint polymerase chain reaction (PCR), semi-quantitative PCR, quantitative PCR (qPCR), high-resolution melt curve analysis (HRMC), and ‘nemabiome’ internal transcribed spacer 2 (ITS-2) amplicon sequencing. Results Both DNA isolation methods yielded comparable results despite poorer DNA purity and faecal contaminant carryover from the low-resource magbead method. GINs were detected in 100% of samples regardless of infection intensity. Co-infections with GINs and coccidia ( Eimeria spp.) were present in most goats, with GIN populations dominated by Haemonchus contortus , Trichostrongylus colubriformis , Trichostrongylus axei , and Oesophagostomum columbianum . Both multiplex PCR and qPCR were highly predictive of GIN species proportions obtained using nemabiome amplicon sequencing; however, HRMC was less reliable than PCR in predicting the presence of particular species. Conclusions These data represent the first ‘nemabiome’ sequencing of GINs from naturally infected smallholder goats in Africa and show the variable nature of GIN co-infections between individual animals. A similar level of granularity was detected by semi-quantitative PCR methods, which provided an accurate summary of species composition. Assessing GIN co-infections is therefore possible using cost-efficient low-resource DNA extraction and PCR approaches that can increase the capacity of molecular resources in areas where sequencing platforms are not available; and also open the door to affordable molecular GIN diagnostics. Given the diverse nature of infections in livestock and wildlife, these approaches have potential for disease surveillance in other areas. Graphical Abstract | Low-cost molecular methods to characterise gastrointestinal nematode co-infections of goats in Africa | 10.1186/s13071-023-05816-y |
2023-06-29 | Background For thirty years, the Harmonic scalpel has been used for precise dissection, sealing and transection. There are numerous meta-analyses on individual surgical procedures with Harmonic, but no overarching review covering all the areas. This umbrella review seeks to summarize the clinical results from the use of Harmonic across surgical fields and broadly quantify its effects on patient outcomes. Methods MEDLINE, EMBASE, and Cochrane Databases were searched for meta-analyses (MAs) of randomized controlled trials (RCTs) comparing Harmonic devices to conventional techniques or advanced bipolar (ABP) devices. For each procedure type, the most comprehensive MAs were evaluated. RCTs not already analysed in a MA were also included. Operating time, length of stay, intraoperative blood loss, drainage volume, pain, and overall complications were evaluated, and the methodological quality and certainty of evidence were assessed. Results Twenty-four systematic literature reviews were identified on colectomy, hemorrhoidectomy, gastrectomy, mastectomy, flap harvesting, cholecystectomy, thyroidectomy, tonsillectomy, and neck dissection. There were also 83 RCTs included. In every MA evaluated, Harmonic devices were associated with either statistically significant or numerical improvements in every outcome compared with conventional techniques; most MAs reported a reduction in operating time of ≥ 25 min. Harmonic versus ABP device MAs in colectomy and thyroidectomy showed no significant differences in outcomes. Conclusion Across surgical procedures, Harmonic devices demonstrated improved patient outcomes for operating time, length of stay, intraoperative bleeding, drainage volume, pain, and overall complications compared to conventional techniques. Additional studies are required to assess differences between Harmonic and ABP devices. | An umbrella review of the surgical performance of Harmonic ultrasonic devices and impact on patient outcomes | 10.1186/s12893-023-02057-9 |
2023-06-27 | Background WRKY transcription factors are a prominent gene family in plants, playing a crucial role in various biological processes including development, metabolism, defense, differentiation, and stress response. Although the WRKY gene family has been extensively studied and analysed in numerous plant species, research on Prunus sibirica ’s WRKY genes ( PsWRKY ) remains lacking. Results This study analysed the basic physicochemical properties, phylogeny, gene structure, cis-acting elements, and Gene ontology (GO) annotation of PsWRKY gene family members using bioinformatics methods based on the whole-genome data of P. sibirica . In total, 55 WRKYs were identified in P. sibirica and were heterogeneously distributed on eight chromosomes. Based on the phylogenetic analysis, these WRKYs were classified into three major groups: Group I, Group II (II-a, II-b, II-c, II-d, II-e), and Group III. Members of different subfamilies have different cis-acting elements, conserved motifs, and intron-exon structures, indicating functional heterogeneity of the WRKY family. Prediction of subcellular localisation indicated that PsWRKYs were mainly located in the nucleus. Twenty pairs of duplicated genes were identified, and segmental duplication events may play an important role in PsWRKY gene family expansion. Analysis of the Ka/Ks ratio showed that the PsWRKY family’s homologous genes were primarily purified by selection. Additionally, GO annotation analysis showed that the WRKY gene family was mainly involved in responses to stimuli, immune system processes, and reproductive processes. Furthermore, quantitative real-time PCR (qRT-PCR) analysis showed that 23 PsWRKYs were highly expressed in one or more tissues (pistils and roots) and PsWRKYs showed specific expression patterns under different low-temperature stress conditions. Conclusions Our results provide a scientific basis for the further exploration and functional validation of WRKYs in P. sibirica . | Genome-wide identification and analysis of the WRKY gene family and low-temperature stress response in Prunus sibirica | 10.1186/s12864-023-09469-0 |
2023-06-26 | The development of infrared (IR) surveillance technology has led to a growing interest in thermal camouflage. However, the tradeoff relationship between low IR-emissivity and thermal insulation hinders the advance of thermal camouflage materials. Herein, guided by multi-physics simulation, we show a design of asymmetric aramid nanofibers/MXene (ANF/MXene) aerogel film that realizes high-efficient thermal camouflage applications. The rationale is that the asymmetric structure contains a thermal-insulation three-dimensional (3D) network part to prevent effective heat transfer and a low IR-emissivity (∼ 0.3) dense surface layer to suppress radiative heat emission. It is remarkable that the synergy mechanism in the topology structure contributes to over 40% reduction of target radiation temperature. Impressively, the tailored asymmetric ANF/MXene aerogel film also enables sound mechanical properties such as a Young’s modulus of 44.4 MPa and a tensile strength of 1.3 MPa, superior to most aerogel materials. It also exhibits great Joule heating performances including low driving voltage (4 V), fast thermal response (< 10 s), and long-term stability, further enabling its versatile thermal camouflage applications. This work offers an innovative design concept to configure multifunctional structures for next-generation thermal management applications. | Tailoring of a robust asymmetric aramid nanofibers/MXene aerogel film for enhanced infrared thermal camouflage and Joule heating performances | 10.1007/s12274-023-5895-4 |
2023-06-25 | Background Chronic low back pain can lead to individual suffering, high medical expenditures, and impaired social well-being. Although the role of physical activity in pain management is well established, the underlying mechanisms of biological and clinical outcomes are unknown. This study aimed to assess the feasibility and acceptability of a pain self-management intervention, Problem-Solving Pain to Enhance Living Well, which employs wearable activity tracking technology and nurse consultations for people with chronic low back pain. Methods This one-arm longitudinal study recruited 40 adults aged 18–60 years with chronic low back pain. Over 12 weeks, participants watched 10 short video modules, wore activity trackers, and participated in nurse consultations every 2 weeks. At baseline and the 12-week follow-up, they completed study questionnaires, quantitative sensory testing, and blood sample collection. Results Forty participants were recruited, and their mean age was 29.8. Thirty-two participants completed the survey questionnaire, quantitative sensory testing, Fitbit activity tracker, and bi-weekly nurse consultation, and 25 completed the evaluation of biological markers. The overall satisfaction with the Problem-Solving Pain to Enhance Living Well video modules, nurse consultations, and Fitbit in pain management was rated as excellent. No adverse events were reported. Between the baseline and 12-week follow-up, there was a significant decrease in pain intensity and interference and an increase in the warm detection threshold at the pain site. Conclusions Despite concerns about the participant burden due to multidimensional assessment and intensive education, the feasibility of the Problem-Solving Pain to Enhance Living Well intervention was favorable. Technology-based self-management interventions can offer personalized strategies by integrating pain phenotypes, genetic markers, and physical activity types affecting pain conditions. Trial registration This pilot study was registered with ClinicalTrials.gov [NCT03637998, August 20, 2018]. The first participant was enrolled on September 21, 2018. | Pain self-management plus activity tracking and nurse-led support in adults with chronic low back pain: feasibility and acceptability of the problem-solving pain to enhance living well (PROPEL) intervention | 10.1186/s12912-023-01365-y |
2023-06-23 | Abstract Composition and seasonal fluctuations of stress dehydrin proteins of Cajander larch ( Larix cajanderi Mayr) growing under extremely cold climatic conditions in Central Yakutia, which are notable for an extraordinary frost resistance, were investigated. Immunoblotting technique made it possible to detect major dehydrins in a molecular mass range of 17–20, 37–42, and 73 kD in the shoots of L. cajanderi for the first time. A high level of polymorphism of dehydrins within a population of L. cajanderi was detected and differences between the examined specimens of trees were mainly revealed in a molecular mass range of 20–37 kD. Within the circannual cycle of larch, the greatest seasonal fluctuations were observed in low-molecular dehydrins, with their content rising at the end of phenological autumn and reaching a steady level in the period of ultralow winter temperatures. The pattern of seasonal fluctuations and wide variety of dehydrins in larch shoots may point to their possible participation in the formation of a unique frost resistance of L. cajanderi upon adaptation of this conifer species to conditions existing in the cryolithozone. | Relationship between Dehydrins and Adaptation of Cajander Larch to Yakutia Cryolithozone Conditions | 10.1134/S1021443723600848 |
2023-06-23 | Abstract Changes in the ultrastructural organization of mesophyll cells during low-temperature adaptation (4°C, 7 days) were studied on seedlings of a frost-resistant variety of winter wheat ( Triticum aestivum L.). It was found that, under the influence of low hardening temperature, wheat leaf cells increased in size, while the area of the cytoplasm increased and the size of the vacuole decreased. The electron density of the cytoplasm visually increased, and numerous vesicles appeared in it. In addition, the size of chloroplasts, as well as the number of chloroplasts, mitochondria, and peroxisomes per unit area of a cell section, increased. Accumulations of mitochondria and peroxisomes in the form of chains were noted near chloroplasts in the cells of hardened seedlings, and the mitochondria themselves changed their shape from round to elongated or dumbbell-shaped. The low temperature also affected the shape of chloroplasts, which became more rounded from lenticular, and outgrowths (stromules) were found in them. Significant changes under the influence of low temperature occurred in the ultrastructure of chloroplasts: the number and size of plastogbules increased; starch inclusions completely disappeared; the number of grana, the average number of thylakoids per grana, the height and area of the grana, the density of photosynthetic membranes in the chloroplast, and the index of grana stacking (ratio length of appressed membranes to the length of non-appressed membranes) decreased. At the same time, in the process of low-temperature hardening, an increased frost resistance of wheat was formed, which was analyzed by the survival rate of seedlings and the release of electrolytes from leaf tissues after testing freezing. The relationship between the found structural transformations in wheat leaf cells and functional and physiological-biochemical changes occurring in cold-tolerant plants in the process of low-temperature adaptation is shown. It is assumed that the observed ultrastructural reorganization of cells is one of the important components in a complex adaptation program as well as a link necessary for the formation of increased resistance of winter cereals to low temperatures. | The Role of Ultrastructural Organization of Cells in Adaptation of Winter Wheat to Low Temperature | 10.1134/S1021443723600873 |
2023-06-23 | Neuromorphic devices with ultra-low energy consumption are highly desired for artificial intelligence and brain-like computing. Here, artificial optoelectronic synaptic devices based on vertical organic field-effect transistors (VOFETs) are fabricated, in which the composite film of the poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl) thieno [3,2-b]thiophene)] and polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) is utilized as the active layer. SEBS is employed to reduce the possibility of source-drain short-circuiting during the device fabrication. Due to the VOFET structure, the device can work at low voltages because of the shorter charge carrier transport distance. Typical biological synaptic performances including excitatory postsynaptic current, short/long-term plasticity, and “learning experience” can be mimicked by the VOFET-based optoelectronic synaptic devices. Importantly, most synaptic functions can be achieved at a low voltage of -0.01 V, and the device still exhibits an obvious response even at an operating voltage of -0.001 V, achieving an ultra-low power consumption of ~ 0.12 fJ, which is among the best reported transistor-based synaptic devices. This work offers a new approach to fabricating neuromorphic electronic devices with ultra-low electric power consumption. Graphical Abstract The vertical field-effect transistor was utilized to fabricate the optoelectronic synapse, achieving a low power consumption of ~ 0.12 fJ. | Artificial optoelectronic synaptic devices based on vertical organic field-effect transistors with low energy consumption | 10.1007/s42114-023-00712-6 |
2023-06-22 | This study investigates the evolution of gaseous pollutants with prevailing meteorology using a network of Alpha sense low-cost portable air monitoring devices deployed to six selected sampling sites namely the Iron steel smelting factory (ISSF), Modomo, Eleweran, Fire service station, staff quarters, and OAU Teaching and research farm (OAUTRF). All six sampling sites were chosen along the pollution hotspot in Ile-Ife. The low-cost sensor has Optical particle counters (OPC-N2) which measured particulate matter and the gaseous pollutants were monitored with electrochemical sensors. At the sites, each sensor unit measured gaseous pollutants: carbon dioxide (CO 2 ), ozone (O 3 ), carbon monoxide (CO), and oxides of nitrogen (NO and NO 2 ). Inbuilt into the monitoring device are temperature and relative humidity (RH) probes as well as a 2-D sonic anemometer to measure wind speed and directions. The directional dependence of the local source of the gaseous pollutant affecting each site was determined using the conditional probability function (CPF) model. The results showed that the highest mean values of 470.6 ppm, 7.2 ppb, and 20.6 ppb for CO 2 , NO, and NO 2 , respectively were recorded at the Modomo site while ISSF and Fire service sites were found to have the highest mean values of 67.9 ppb and 517.6 ppb, respectively for O 3 and CO during the observational period. The mean values for temperature were noticed to increase in trend from OAUTRF (24.9 °C) to ISSF (26.0 °C). Also, CO 2 gave a good relationship with meteorological parameters with R 2 value ranging from 0.26 to 0.89 in all the sampling sites except ISSF. On contrary, weak relationships were found between the meteorological variables and other gaseous pollutants other than CO 2 for both day and nighttime periods. The CPF model indicated that a larger percentage of the elevated O 3 , NO and NO 2 were associated with pollutant transport at wind speed $$>2 m/s$$ > 2 m / s due to low event number. This study concludes that there is evidence of a significant effect of meteorological parameters on the gaseous pollutants as observed, while, the CPF plot shows a good agreement with the location of known pollution sources. | Investigating the evolution of gaseous air pollutants with prevailing meteorology across selected sites within a pollution hotspot in Ile-Ife, Southwestern Nigeria | 10.1007/s44274-023-00006-0 |
2023-06-21 | Magnesium (Mg) alloys are the lightest metal structural material for engineering applications and therefore have a wide market of applications. However, compared to steel and aluminum alloys, Mg alloys have lower mechanical properties, which greatly limits their application. Extrusion is one of the most important processing methods for Mg and its alloys. However, the effect of such a heterogeneous microstructure achieved at low temperatures on the mechanical properties is lacking investigation. In this work, commercial AZ80 alloys with different initial microstructures (as-cast and as-homogenized) were selected and extruded at a low extrusion temperature of 220 °C and a low extrusion ratio of 4. The microstructure and mechanical properties of the two extruded AZ80 alloys were investigated. The results show that homogenized-extruded (HE) sample exhibits higher strength than the cast-extruded (CE) sample, which is mainly attributed to the high number density of fine dynamic precipitates and the high fraction of recrystallized ultrafine grains. Compared to the coarse compounds existing in CE sample, the fine dynamical precipitates of Mg 17 (Al, Zn) 12 form in the HE sample can effectively promote the dynamical recrystallization during extrusion, while they exhibit a similar effect on the size and orientation of the recrystallized grains. These results can facilitate the designing of high-strength wrought magnesium alloys by rational microstructure construction. | Effect of Initial Microstructure Prior to Extrusion on the Microstructure and Mechanical Properties of Extruded AZ80 Alloy with a Low Temperature and a Low Ratio | 10.1186/s10033-023-00901-w |
2023-06-20 | For humanity to complete its ambitious solar system exploration, it is crucial to comprehend how terrestrial life reacts to differing planet gravity. We followed the life trajectory of an earth cotton seed's germination, development, and ultimate fate after prolonged exposure to extremely low temperatures using the life-regeneration ecosystem carried by Chang'e 4 probe, which landed on the Moon on January 3rd, 2019, for the first time in human history. In a controlled environment with similar characteristics, such as temperature, humidity, air pressure, and nutrition, we compared this life trajectory on the moon to that on Earth, except for the differences in gravity, light, and radiation. We discovered that the 1/6 g moon gravity speeds up seed germination. Surprisingly, Moon seed-lings demonstrated rapid acclimatization to super-freezing (below minus 52 degrees Celsius) under 1/6 g lunar gravity, maintaining upright and green despite exposure to long-term extremely cold temperatures for 18–24 hours. Based on cellular and molecular reactions caused by moon-low gravity, we suggest probable mechanisms for cold resilience. These unique findings will enhance our understanding of how plants adapt to suboptimal environmental conditions in space. | The Lunar One-Sixth Low Gravity Conduciveness to the Improvement of the Cold Resistance of Plants | 10.1007/s12217-023-10058-9 |
2023-06-19 | Stress relaxation property is critical to evaluating low temperature anti-cracking performance of asphalt materials. A preliminary attempt was made to measure and model the short term stress relaxation behavior of the wet process crumb rubber modified asphalt binder within linear viscoelastic (LVE) region. The strain amplitude sweep test was implemented with a dynamic shear rheometer to identify the LVE region and maximum critical strain of the asphalt. Subsequently, the stress relaxation curve of the sample binder was obtained by carrying out the shear stress relaxation test, which was then fitted using the Zener model and Power law model to set up the stress relaxation model. Results showed the maximum critical strain of crumb rubber modified asphalt at 10 °C ~ 15 °C was around 1%, suggesting the control strain should not surpass 1% when trying to capture the linear viscoelastic behavior of crumb rubber modified asphalt at lower temperatures. Additionally, higher temperature related to greater maximum critical strain and broader linear viscoelastic region, and crumb rubber content showed limited effect on the maximum critical strain whereas it showed significant effect on the storage and loss moduli and phase angle of the asphalt. Furthermore, the stress inside the asphalt finally relaxed to zero at 10 °C ~ 15 °C, suggesting typical viscoelastic liquid behavior. Its relaxation process could be divided into the rapid relaxation stage and steady relaxation stage. Temperature showed obvious influence on the relaxation property at the rapid relaxation stage and lower temperature led to greater relaxation modulus. However, the influence of temperature in the steady relaxation stage was limited. The Power law model was more preferred than the Zener model because it better represented the viscoelastic liquid behavior of the crumb rubber modified asphalt. This work was expected to shed some light on evaluation of the low temperature stress relaxation performance of crumb rubber modified asphalt and to promote the application of crumb rubber modified asphalt technology under the “carbon neutrality” background. | Experiment and Representation of Stress Relaxation Behavior of Crumb Rubber Modified Asphalt | 10.1007/s42947-023-00344-5 |
2023-06-19 | The use of reclaimed asphalt pavement (RAP) in road construction is expected to lead to a sustainable asphalt pavement system by reducing the environmental footprint as well as the cost in construction materials. However, the use of RAP in road construction results in a stiffer pavement and could cause the need for early rehabilitation than the traditional road management cycle. In this regard, a novel laboratory aging method is proposed where the new protocol, unlike the traditional simulation method, simulates the expected rehabilitation period. Here, different desired mixtures are aged five hours at 135 °C in the laboratory, while the corresponding mixtures are aged naturally and evaluated periodically for 30 months. The Bending Beam Rheometer (BBR) was used to evaluate the stiffness characteristics of the mixtures. Finally, the evaluation is carried out using an Artificial Intelligence-based approach, namely regression tree, by observing the minute details of stiffness and relaxation capacity instead of the traditional index value. It is observed that the samples aged in the laboratory for five hours at 135 °C simulate 2 years of field aging. The proposed accelerated laboratory procedure is expected to be a comparatively practical simulation procedure for RAP-incorporated mixture to achieve a two-year real-field aging condition for a cold region. | Laboratory Simulation of RAP Incorporated Mix in a Cold Region: An Artificial Intelligence-Based Approach | 10.1007/s42947-023-00346-3 |
2023-06-16 | To control the precipitation sites of carbides, the cold rolling, annealing, and aging processes were employed to process Fe-26Mn-10.2Al-0.98C-0.15 V (wt.%) steels with duplex structure. After aging, the alloy achieved a good combination of strength and plasticity, which had a yield strength of 1120 MPa, tensile strength of 1285 MPa, and elongation of 17%. The precipitation strengthening of the κ-carbides shows a significant contribution to the high yield strength of this alloy. The strengthening models were employed to calculate the precipitation strengthening from coherent κ-carbides, and show good prediction performance. The increase in strength slows down with increasing aging time, which is influenced by the critical grain size of the precipitated particles and the antiphase boundary energy ( $${\gamma }_{\mathrm{APB}}$$ γ APB ). Furthermore, the deformation mechanism of this alloy is influenced by the high SFE and the softening effect of the intragranular κ-carbide sliding surface. The analyses of the deformed structure revealed that the plastic deformation was dominated by the planar slip, resulting in the formation of the Taylor lattice, a special dislocation substructure. | Deformation Structures and Strengthening Mechanisms Associated with κ-Carbides Precipitation in an Austenitic-Based Low-Density Steel | 10.1007/s11665-023-08420-4 |
2023-06-15 | Troctolites were recovered during Integrated Ocean Drilling Program Expedition 345 at the Hess Deep Rift, next to fast-spreading East Pacific Rise. These troctolites are divided into three groups based on textural differences: coarse-grained (1–10 mm in length) troctolite, fine-grained (~ 2 mm in length) troctolite, and skeletal olivine-bearing troctolite. All troctolites exhibit a magmatic fabric. The major-element compositions of olivine, plagioclase, and clinopyroxene in the troctolites are intermediate between those of Hess Deep gabbros and harzburgites. The trace-element compositions of olivine, plagioclase, and clinopyroxene in the troctolites overlap with those of troctolites from slow-spread crust, but they record no petrographic evidence indicating assimilation of mantle peridotite. Thermodynamic calculation for mineral chemistry showed that fractional crystallization of melt is the dominant process responsible for the formation of the troctolites. The fine-grained troctolite was crystallized with high crystallization rate resulting from hot melt injection into colder wall gabbro. In contrast, interactions between the unsolidified troctolite containing interstitial melt and newly injected melt resulted in the formation of the skeletal olivine-bearing troctolite. While our results demonstrate that the troctolites exhibit multiple melt injections and partial dissolution of a troctolite precursor, fractional crystallization is the dominant process for the creation of the lower crust in the Hess Deep Rift. | Formation of lower fast-spread oceanic crust: a structural and geochemical study of troctolites in the Hess Deep Rift (East Pacific Rise) | 10.1186/s40645-023-00560-4 |
2023-06-14 | The observation of geomagnetic field variations is an important approach to studying earthquake precursors. Since 1987, the China Earthquake Administration has explored this seismomagnetic relationship. In particular, they studied local magnetic field anomalies over the Chinese mainland for earthquake prediction. Owing to the years of research on the seismomagnetic relationship, earthquake prediction experts have concluded that the compressive magnetic effect, tectonic magnetic effect, electric magnetic fluid effect, and other factors contribute to preearthquake magnetic anomalies. However, this involves a small magnitude of magnetic field changes. It is difficult to relate them to the abnormal changes of the extremely large magnetic field in regions with extreme earthquakes owing to the high cost of professional geomagnetic equipment, thereby limiting large-scale deployment. Moreover, it is difficult to obtain strong magnetic field changes before an earthquake. The Tianjin Earthquake Agency has developed low-cost geomagnetic field observation equipment through the Beijing–Tianjin–Hebei geomagnetic equipment test project. The new system was used to test the availability of equipment and determine the findings based on big data. | Design and implementation of low-cost geomagnetic field monitoring equipment for high-density deployment | 10.1007/s11770-023-1015-1 |
2023-06-14 | This paper presents a digital low computation detection method for signal nonlinear distortion. After presetting ADC sampling rate and completing data sampling, the low sampling rate data extracted from the sampling data complete the autocorrelation analysis to correct and calculate the accurate fundamental frequency. According to the relationship between the fundamental frequency and the sampling rate, the complete periodic segment data of the signal cutting out from the sampling data carry out the digital quadrature detection operation to obtain the value of each harmonic component and nonlinear distortion. Experiments show that the calculation of this method is less than that of FFT spectrum analysis method when measuring the THD lower than 15 order. When calculating the 15-order THD at 1024 points, the calculation time is reduced by 44.26%. Moreover, the digital quadrature detection method has high measurement accuracy with less than 0.6% error of detecting 5-order THD. | A low computation detection method of signal nonlinear distortion based on digital quadrature detection principle | 10.1186/s13634-023-01015-0 |
2023-06-13 | Radon is found in various rocks as a naturally occurring radioactive gas. It is crucial to estimate the radon emission characteristics of different in situ rocks in the pre-mountain fracture zone of the northern foot of the Qinling Mountains in China for radiation risk prevention, as several inhabitants occupy the area. This paper analyzes the pore structure and radon gas emission characteristics of granite, gneiss, limestone, and sandstone by low-temperature nitrogen adsorption (LTNA) test, nuclear magnetic resonance (NMR) test, scanning electron microscope (SEM) test, and radon gas (Rn-222) measurements. Based on the findings of the study, the order of radon emission rate from high to low is granite, gneiss, limestone, and sandstone, and the volume of micropores ( r < 2 nm) is positively correlated to the radon emission rate. Furthermore, mesopores (2 nm < r < 50 nm) are the major components of rock pore structure. The sandstone and limestone show a negative correlation of radon emission rates with the mesopore fractal dimensions (based on LTNA and NMR). The radon emission is inhibited for complex mesopore structures. The results of the study can help to understand the mechanisms influencing the radon emission process in rocks and to guide assessments of the radon potential in the region and radiation risk in rocks. | Study on the pore structure and radon emission characteristics of typical rocks in the Lintong area | 10.1007/s10064-023-03285-2 |
2023-06-13 | Background Insulinomas are rare neuroendocrine tumors that typically present with hypoglycemic crises. Peripheral neuropathy is an uncommon complication of insulinoma. Most clinicians expect peripheral neuropathy symptoms to reverse completely after the insulin-secreting tumor is resected, but this may be a misassumption. Case report We report a case of a 16-year-old Brazilian boy with clonic muscle spasms of the lower limbs for almost one year. Disabling paraparesis and confusional episodes had progressively set in as well. There were no sensorial abnormalities in the lower limbs, upper limbs or cranial nerves. An electromyography revealed a motor neuropathy of the lower limbs. The diagnosis of insulinoma was established as serum insulin and C-peptide concentrations were inappropriately normal during spontaneous episodes of hypoglycemia. Following a normal abdominal magnetic resonance scan, the imaging work-up continued with an endoscopic ultrasound, which localized the tumor at the pancreatic body-tail transition. Once localized, a prompt surgical removal (enucleation) of the tumor was undertaken, leading to an immediate and complete resolution of hypoglycemia. The time length between the onset of symptoms and tumor resection was 15 months. After surgery, the symptoms of peripheral neuropathy of the lower limbs showed a slow and only partial improvement. At a two-year follow-up after surgery, although being able to lead a normal and productive life, the patient still reported symptoms of reduced muscular strength in the lower limbs and a new electroneuromyography analysis showed chronic denervation and reinnervation in the legs’ muscles—indicating chronic neuropathic injury. Conclusion The events of this case reinforce the importance of an agile diagnostic work-up and spry definitive treatment for patients with this uncommon disease, enabling the cure of neuroglycopenia before permanent bothersome complications ensue. | Insulinoma with peripheral neuropathy: a case report | 10.1186/s13256-023-03963-5 |
2023-06-12 | Background Septic and aseptic nonunion require different therapeutic strategies. However, differential diagnosis is challenging, as low-grade infections and biofilm-bound bacteria often remain undetected. Therefore, the examination of biofilm on implants by sonication and the evaluation of its value for differentiating between femoral or tibial shaft septic and aseptic nonunion in comparison to tissue culture and histopathology was the focus of this study. Materials and methods Osteosynthesis material for sonication and tissue samples for long-term culture and histopathologic examination from 53 patients with aseptic nonunion, 42 with septic nonunion and 32 with regular healed fractures were obtained during surgery. Sonication fluid was concentrated by membrane filtration and colony-forming units (CFU) were quantified after aerobic and anaerobic incubation. CFU cut-off values for differentiating between septic and aseptic nonunion or regular healers were determined by receiver operating characteristic analysis. The performances of the different diagnostic methods were calculated using cross-tabulation. Results The cut-off value for differentiating between septic and aseptic nonunion was ≥ 13.6 CFU/10 ml sonication fluid. With a sensitivity of 52% and a specificity of 93%, the diagnostic performance of membrane filtration was lower than that of tissue culture (69%, 96%) but higher than that of histopathology (14%, 87%). Considering two criteria for infection diagnosis, the sensitivity was similar for one tissue culture with the same pathogen in broth-cultured sonication fluid and two positive tissue cultures (55%). The combination of tissue culture and membrane-filtrated sonication fluid had a sensitivity of 50%, which increased up to 62% when using a lower CFU cut-off determined from regular healers. Furthermore, membrane filtration demonstrated a significantly higher polymicrobial detection rate compared to tissue culture and sonication fluid broth culture. Conclusions Our findings support a multimodal approach for the differential diagnosis of nonunion, with sonication demonstrating substantial usefulness. Level of Evidence : Level 2 Trial registration DRKS00014657 (date of registration: 2018/04/26) | The value of sonication in the differential diagnosis of septic and aseptic femoral and tibial shaft nonunion in comparison to conventional tissue culture and histopathology: a prospective multicenter clinical study | 10.1186/s10195-023-00708-4 |
2023-06-11 | Low temperature (LT) disrupted the osmotic regulation system and sucrose and nitrogen metabolism of Bitter gourd ( Momordica charantia L.). The osmotic regulation system and the sucrose and nitrogen metabolism in bitter gourd were investigated in ungrafted (M), self-grafted (MS), and grafted onto rootstocks of pumpkin ( Cucurbita moschata Duch . , MC) and loofah ( Luffa cylindrica Roem., ML) exposed to LT (8 °C) for 24 h and then allowed to recover growth (RG; 24/18 °C) for 24 h. MC and ML maintained better osmotic adjustment ability. Gas exchange parameters of MC and ML are higher than M and MS under both LT and RG. However, chloroplast fluorescence parameters varied considerably for the different groups under LT and RG. The soluble sugar and sucrose contents and sucrose phosphatase and sucrose synthase synthesis activities of MC leaves under LT and RG were higher than those of M and MS, however, the changes of these indexes in ML are not as obvious as that of MC. The activities of the sucrose-decomposing enzymes neutral invertase and acid invertase in ML and MC were lower than those of M and MS. After the induction of LT and RG, the nitrogen metabolites and enzyme activities of M and MS leaves were significantly reduced, while the MC and ML seedlings were on the contrary and the ammonium content in the leaves was significantly reduced. Pumpkin as rootstock can improve the LT tolerance of bitter gourd and using this method may help expand the planting area and season of bitter gourd. | Interspecific rootstocks improve the low-temperature resistance of bitter gourd through sucrose and nitrogen metabolism regulation | 10.1007/s11738-023-03577-w |
2023-06-08 | Pharmaceutical products found in wastewater and various water systems have become an environmental concern. Various processes were developed to remove various pharmaceuticals, including adsorption processes utilizing activated carbon adsorbents derived from agricultural wastes. The present study investigates the removal of carbamazepine (CBZ) from aqueous solutions by activated carbon (AC) derived from pomegranate peels (PGPs). The prepared AC was characterized by FTIR. The adsorption kinetics of CBZ on AC-PGPs was well represented by the pseudo-second-order kinetic model. Moreover, the data were well explained by Freundlich and Langmuir isotherm models. The effect of various parameters (including pH, temperature, CBZ concentration, the adsorbent dosage, and contact time) on the efficiency of CBZ removal by AC-PGPs was studied. The CBZ removal efficiency was not affected by changes in pH values but was slightly enhanced at the outset of the adsorption experiment with increasing temperature. The highest percentage removal efficiency was 98.0% at 23 °C when the optimum adsorbent dose was determined as 400.0 mg and the CBZ initial concentration was 20.0 mg L −1 . The general and potential applicability of this method is presented by using available agricultural wastes as a low-cost source of AC and as an efficient removal method of pharmaceuticals from aqueous solutions. | Activated carbon-based pomegranate peels as an efficient removal method for carbamazepine | 10.1007/s10661-023-11393-5 |
2023-06-08 | Changes in the milk microbiota during the course of mastitis are due to the nature of a sporadic occurring disease difficult to study. In this study we experimentally induced mastitis by infusion of Escherichia coli endotoxins in one udder quarter each of nine healthy lactating dairy cows and assessed the bacteriological dynamics and the milk microbiota at four time points before and eight time points after infusion. As control, saline was infused in one udder quarter each of additionally nine healthy cows that followed the same sampling protocol. The milk microbiota was assessed by sequencing of the 16 S rRNA gene and a range of positive and negative controls were included for methodological evaluation. Two different data filtration models were used to identify and cure data from contaminating taxa. Endotoxin infused quarters responded with transient clinical signs of inflammation and increased SCC while no response was observed in the control cows. In the milk microbiota data no response to inflammation was identified. The data analysis of the milk microbiota was largely hampered by laboratory and reagent contamination. Application of the filtration models caused a marked reduction in data but did not reveal any associations with the inflammatory reaction. Our results indicate that the microbiota in milk from healthy cows is unaffected by inflammation. | Absence of changes in the milk microbiota during Escherichia coli endotoxin induced experimental bovine mastitis | 10.1186/s13567-023-01179-5 |
2023-06-08 | Background High-resolution sound and movement recording tags offer unprecedented insights into the fine-scale foraging behaviour of cetaceans, especially echolocating odontocetes, enabling the estimation of a series of foraging metrics. However, these tags are expensive, making them inaccessible to most researchers. Time-Depth Recorders (TDRs), which have been widely used to study diving and foraging behaviour of marine mammals, offer a more affordable alternative. Unfortunately, data collected by TDRs are bi-dimensional (time and depth only), so quantifying foraging effort from those data is challenging. Methods A predictive model of the foraging effort of sperm whales ( Physeter macrocephalus ) was developed to identify prey capture attempts (PCAs) from time-depth data. Data from high-resolution acoustic and movement recording tags deployed on 12 sperm whales were downsampled to 1 Hz to match the typical TDR sampling resolution and used to predict the number of buzzes (i.e., rapid series of echolocation clicks indicative of PCAs). Generalized linear mixed models were built for dive segments of different durations (30, 60, 180 and 300 s) using multiple dive metrics as potential predictors of PCAs. Results Average depth, variance of depth and variance of vertical velocity were the best predictors of the number of buzzes. Sensitivity analysis showed that models with segments of 180 s had the best overall predictive performance, with a good area under the curve value (0.78 ± 0.05), high sensitivity (0.93 ± 0.06) and high specificity (0.64 ± 0.14). Models using 180 s segments had a small difference between observed and predicted number of buzzes per dive, with a median of 4 buzzes, representing a difference in predicted buzzes of 30%. Conclusions These results demonstrate that it is possible to obtain a fine-scale, accurate index of sperm whale PCAs from time-depth data alone. This work helps leveraging the potential of time-depth data for studying the foraging ecology of sperm whales and the possibility of applying this approach to a wide range of echolocating cetaceans. The development of accurate foraging indices from low-cost, easily accessible TDR data would contribute to democratize this type of research, promote long-term studies of various species in several locations, and enable analyses of historical datasets to investigate changes in cetacean foraging activity. | Predictive model of sperm whale prey capture attempts from time-depth data | 10.1186/s40462-023-00393-2 |
2023-06-07 | Low plasticity clays are found in abundance worldwide, exerting undue stresses on civil structures, road pavements and railway infrastructure, owing to the periodic settlement caused by their low bearing capacity and slight swelling potential. They are often encountered as natural soil when constructing road subgrade and have the potential to compromise the integrity of the entire pavement system unless improved appropriately. Furthermore, the accumulation of vast quantities of non-biodegradable glass waste is identified as a challenge in many countries. Considering the above, this paper aims to provide a sustainable solution by studying the effect of crushed glass (CG) at varied inclusions of 0, 5, 10, 15 and 20% in a clay subgrade. The testing procedure implemented includes three distinct testing phases, namely, material properties, microstructural properties and mechanical strength tests. The material property tests involved particle size distribution, X-ray fluorescence (XRF) and X-ray diffraction (XRD) testing. Microstructural tests considered include scanning electron microscope (SEM) and micro-CT (CT) testing, which enabled a vital understanding of how the introduction of glass affects the internal structure of the clay matrix, where an increase in the porosity was evident upon adding CG. The mechanical testing phase involved standard compaction, unconfined comprehensive strength (UCS), California bearing ratio (CBR), resilient modulus and swelling–shrinkage tests. It can be concluded that introducing CG improved the clay’s mechanical strength with respect to UCS, CBR and resilient modulus whilst also reducing its swelling potential, where the optimum inclusion of CG at 15% best enhanced the mechanical strength properties of the low plasticity clay. | Improvement of Low Plasticity Clay with Crushed Glass: A Mechanical and Microstructural Study | 10.1007/s42947-023-00339-2 |
2023-06-06 | Background To investigate the effect of low-intensity pulsed ultrasound (LIPUS) combined with lipid microbubbles on the proliferation and bone regeneration of bone marrow mesenchymal stem cells (BMSCs) in poly (lactic-glycolic acid copolymer) (PLGA)/α-tricalcium phosphate (TCP) 3D-printed scaffolds. Methods BMSCs were irradiated with different LIPUS parameters and microbubble concentrations, and the best acoustic excitation parameters were selected. The expression of type I collagen and the activity of alkaline phosphatase were detected. Alizarin red staining was used to evaluate the calcium salt production during osteogenic differentiation. Results BMSCs proliferation was the most significant under the condition of 0.5% (v/v) lipid microbubble concentration, 2.0 MHz frequency, 0.3 W/cm 2 sound intensity and 20% duty cycle. After 14 days, the type I collagen expression and alkaline phosphatase activity in the scaffold increased significantly compared to those in the control group, and alizarin red staining showed more calcium salt production during osteogenic differentiation. After 21 days, scanning electron microscopy experiments showed that osteogenesis was obvious in the PLGA/TCP scaffolds. Conclusion LIPUS combined with lipid microbubbles on PLGA/TCP scaffolds can promote BMSCs growth and bone differentiation, which is expected to provide a new and effective method for the treatment of bone regeneration in tissue engineering. | Enhanced bone regeneration by low-intensity pulsed ultrasound and lipid microbubbles on PLGA/TCP 3D-printed scaffolds | 10.1186/s12896-023-00783-9 |
2023-06-06 | Introduction It has not yet been possible to ascertain the exact proportion, characterization or impact of low-acuity emergency department (ED) attendances on the German Health Care System since valid and robust definitions to be applied in German ED routine data are missing. Methods Internationally used methods and parameters to identify low-acuity ED attendances were identified, analyzed and then applied to routine ED data from two EDs of the tertiary care hospitals Charité—Universitätsmedizin Berlin, Campus Mitte (CCM) and Campus Virchow (CVK). Results Based on the three routinely available parameters `disposition´, `transport to the ED´ and `triage´ 33.2% ( n = 30 676) out of 92 477 presentations to the two EDs of Charité—Universitätsmedizin Berlin (CVK, CCM) in 2016 could be classified as low-acuity presentations. Conclusion This study provides a reliable and replicable means of retrospective identification and quantification of low-acuity attendances in German ED routine data. This enables both intra-national and international comparisons of figures across future studies and health care monitoring. | Identification of low-acuity attendances in routine clinical information documented in German Emergency Departments | 10.1186/s12873-023-00838-2 |
2023-06-06 | Introduction Lower respiratory tract infections (LRTIs) caused by drug-resistant pathogenic bacteria is a major problem in developing countries including Ethiopia. Therefore, this study aimed to determine the pathogenic bacteria and their antimicrobial susceptibility patterns among Gene X-pert tuberculosis-negative adult patients with clinically suspected LRTIs at the University of Gondar Comprehensive Specialized Referral Hospital, Gondar, Northwest Ethiopia. Methods This institutional-based cross-sectional study was conducted from February 01 to March 15, 2020. Socio-demographic data were collected by using a structured questionnaire. A total of 254 sputum specimens were collected from Gene X-pert tuberculosis-negative patients. Bacterial recovery was performed using blood, chocolate, and MacConkey agar plates. Bacterial isolates were identified based on Gram staining, colony characteristics, and biochemical reactions. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method. Methicillin resistance of S. aureus was confirmed using cefoxitin (30 µg). Descriptive statistics were calculated for each variable and results are shown in tables and figures. Results In this study, the overall sputum culture positivity rate was 145/254 (57.1%). Gram-negative bacteria 111 (64.9%) were predominant compared to Gram-positive bacteria 60 (35.1%). Of the 145 culture-positive cases, 26 (14.8%) had poly-bacterial infections. S. aureus 40 (66.7%) was the predominant Gram-positive bacterium whereas K. pneumoniae 33 (29.7%), was the most isolated Gram-negative bacterium. Bacterial species, such as S. aureus were sensitive to ciprofloxacin 38/40 (95.0%), gentamicin 37/40 (92.5%), cefoxitin 36/40 (90.0%), and clindamycin 34/40 (85.0%). The proportion of Methicillin-resistant S. aureus was low, 4(10.0%). S. pneumoniae was sensitive to chloramphenicol 8/9 (88.9%) and resistant to ciprofloxacin 6/9 (66.7%). K pneumoniae , P. aeruginosa, E. coli , Serratia species, and H. influenzae also demonstrated high levels of resistance to ampicillin at rates of 21/33 (63.6%), 8/8 (100.0%), 15/17 (88.2%), 7/10 (70.0%), and 6/6 (100.0%), respectively. Conclusion This study revealed a higher burden of Gram-negative and Gram-positive pathogenic bacterial agents, which is responsible for LRTs. Therefore, routine sputum culture identification and antibiotic susceptibility testing should be performed in Gene X-pert tuberculosis-negative patients. | Pathogenic bacteria recovered from Gene X-pert tuberculosis-negative adult patients in Gondar, Northwest Ethiopia | 10.1186/s12890-023-02500-w |
2023-06-05 | It is of great significance to study the mechanical properties of rocks with different saturations for safe and efficient development of geotechnical engineering in low-temperature environments, such as open-pit mining and tunnel excavation in winter in cold areas, and etc. In this paper, the LT-SHPB test system was used to carry out impact loading tests for sandstones with various saturations at − 20 °C environment. SEM was used to observe the cross-sectional characteristics of the specimens. The distributions of fragments were obtained by screening after impact failure. The energy dissipation model was established during the failure process. The research results indicated that the failure strength, elastic modulus, and peak strain of sandstones showed significant strain rate strengthening. Under the fixed strain rate, as the increase of the water content, the failure strength and elastic modulus and the sensitivity increased first and then decreased, while the peak strain showed the opposite change characteristics. 75% saturation was the turning point of the change. The sandstones under saturated water content exhibited remarkable ductile failure characteristics, while the brittle failure dominated in other conditions. The fundamental reason for this change was the difference between the freezing and frost heave effects of water-bearing specimens under low temperature conditions. The change characteristics of the macroscopic damage degree of sandstones with the strain rate and water content were basically the same as the characteristics of mechanical properties. The higher the internal density, the more the dissipated energy and surface specific energy for the whole failure of the specimen. The energy dissipation difference could directly change the macroscopic failure characteristics. The LT-SHPB test system was used to carry out impact loading tests for sandstones with various saturations at − 20 °C environment. SEM was used to observe the cross-sectional characteristics of the specimens. The distributions of fragments were obtained by screening after impact failure. The energy dissipation model of sandstones with different saturations at low temperatures was established during the failure process. | Study on dynamic mechanical response characteristics and fracture energy dissipation mechanism of sandstones with different saturations under real-time low temperature | 10.1007/s40948-023-00622-3 |
2023-06-05 | A plasma chemistry model is developed to study the evolution of species during the synthesis of iron oxide nanoparticles from ferrocene precursor in non-equilibrium argon or argon–hydrogen plasma. The model includes electron-induced reactions, charge exchange reaction and neutral–neutral reactions. While the rate constants for neutral–neutral reactions are taken from the available literature, those of electron induced reactions, charge exchange reactions, and Penning reactions are determined from available models. The effect of pressure and hydrogen gas flow on iron species formation in the plasma is studied. The presence of hydrogen gas in the plasma leads to the formation of hydrogen atom radicals that help in the dissociation of ferrocene to form intermediates, which in turn lead to formation of iron. Overall, the model predicts that addition of hydrogen gas and high working pressure results in improving iron formation, thus increasing the iron content in nanoparticles. This is in good agreement with previous experimental results. The model gives a basic understanding of a ferrocene–argon–hydrogen plasma and provides a basic building block for future studies in particle formation and growth in iron oxide nanoparticle synthesis. | Modeling nanoparticle synthesis process using ferrocene/Ar/H2 low pressure RF plasma | 10.1007/s12008-023-01387-5 |
2023-06-05 | Background Bacteria colonizing the nasopharynx play a key role as gatekeepers of respiratory health. Yet, dynamics of early life nasopharyngeal (NP) bacterial profiles remain understudied in low- and middle-income countries (LMICs), where children have a high prevalence of risk factors for lower respiratory tract infection. We investigated longitudinal changes in NP bacterial profiles, and associated exposures, among healthy infants from low-income households in South Africa. Methods We used short fragment (V4 region) 16S rRNA gene amplicon sequencing to characterize NP bacterial profiles from 103 infants in a South African birth cohort, at monthly intervals from birth through the first 12 months of life and six monthly thereafter until 30 months. Results Corynebacterium and Staphylococcus were dominant colonizers at 1 month of life; however, these were rapidly replaced by Moraxella- or Haemophilus -dominated profiles by 4 months. This succession was almost universal and largely independent of a broad range of exposures. Warm weather (summer), lower gestational age, maternal smoking, no day-care attendance, antibiotic exposure, or low height-for-age z score at 12 months were associated with higher alpha and beta diversity. Summer was also associated with higher relative abundances of Staphylococcus , Streptococcus , Neisseria , or anaerobic gram-negative bacteria, whilst spring and winter were associated with higher relative abundances of Haemophilus or Corynebacterium , respectively. Maternal smoking was associated with higher relative abundances of Porphyromonas . Antibiotic therapy (or isoniazid prophylaxis for tuberculosis) was associated with higher relative abundance of anerobic taxa ( Porphyromonas , Fusobacterium , and Prevotella ) and with lower relative abundances of health associated-taxa Corynebacterium and Dolosigranulum . HIV-exposure was associated with higher relative abundances of Klebsiella or Veillonella and lower relative abundances of an unclassified genus within the family Lachnospiraceae. Conclusions In this intensively sampled cohort, there was rapid and predictable replacement of early profiles dominated by health-associated Corynebacterium and Dolosigranulum with those dominated by Moraxella and Haemophilus , independent of exposures. Season and antibiotic exposure were key determinants of NP bacterial profiles. Understudied but highly prevalent exposures prevalent in LMICs, including maternal smoking and HIV-exposure, were associated with NP bacterial profiles. Video Abstract | Succession and determinants of the early life nasopharyngeal microbiota in a South African birth cohort | 10.1186/s40168-023-01563-5 |
2023-06-05 | Background Global crises, regardless of the place where they started to spread or of the factors that triggered them, require a comprehensive approach, primarily based on good communication, cooperation and mutual support. No individual and no institution should remain indifferent to crises but, on the contrary, be fully aware that any involvement in curbing them matters. Although humanity can be affected by various types of crises, in this paper we refer to the one related to COVID-19 pandemic. There are certain reasons that come to justify our choice: first of all, being a shock with a strong impact on people, its analysis should be performed from several angles; this may bring to light an image with its disparate propagation and measures to counteract it both in developed countries, and especially in those with a shortage of resources. Secondly, in the context of the emergence of vaccines against COVID-19, it is helpful to have an overview of COVID-19 through the lens of the relationship between the vaccination process and the elements that characterize governance, with a differentiated dashboard by country categories worldwide: low, middle and high-income countries. Our study is far from capturing the complexity arising from such social problem, but rather aims to outline the defining role of governance when it comes to providing firm reactions to the COVID-19 crisis. Methods Given that our sample consists of a large number of countries, namely 170, first, examined all together, and then, split into three groups (high, middle and low-income), it is challenging to address governance in association with COVID-19 vaccination, in order to see how much they interact and how each of the six aggregate governance indicators of the World Bank (Worldwide Governance Indicators) is reflected in this process. Even if they do not oscillate strongly over relatively short periods of time, reporting on health issues requires a sequential inventory, considering closer time intervals, so as to be able to act promptly. Thus, to better distinguish how the COVID-19 vaccination process evolved in low, middle and high-income countries, but also how it was imprinted by governance, we present the situation quarterly (March, June, September and December), in 2021, the year when the immunization campaigns were the most intense at the global level. Regarding the applied methods, we mention both OLS regressions with robust estimators and a panel model, used to investigate the determinants of COVID-19 vaccination, some of them describing the good governance, as well as other dimensions. Results The findings point out that the influence of governance on COVID-19 vaccination differs depending on whether a country belongs to high, middle or low-income typology: the strongest determinism of governance on vaccination is encountered in high-income countries, and the weakest in low-income ones; in some cases, governance does not matter significantly. However, exploring the three groups of states included in the research, it is observed that the most relevant factors in this relationship are government effectiveness, regulatory quality and control of corruption. Conclusions Besides the order of importance of governance indicators on COVID-19 vaccination, our study indicates that, overall, governance positively shapes the vaccination rate at the level of the chosen sample. In normative terms, these findings can be translated particularly by the fact that they can serve as information to raise awareness on the relevance of the existence of an institutional framework that allows the formulation of strategies according to the patterns of each country, especially since the actionable tools depend on the available resources. As a general conclusion, public policies should be designed in such a way as to strengthen trust in vaccination regulations and in governments, to reduce the multifaceted negative effects of this health crisis and to hope for its total end. | COVID-19 vaccination and governance in the case of low, middle and high-income countries | 10.1186/s12889-023-15975-3 |
2023-06-05 | Tinnitus is a perception disorder of sound with no hearing impulse. It is a very common otology complaint that leads to worsening quality of life. The experience of sound is only the product of neural system activity, with no matching mechanical or vibratory activity in the cochlea, and is unrelated to any external stimuli. Low-level laser therapy (LLLT) is a medical treatment of tinnitus that uses low-energy-level lasers or light-emitting diodes to stimulate or inhibit cellular function. The study included nine patients aged 20–68 years with unilateral or bilateral tinnitus. It was a self-controlled clinical trial study on subjective tinnitus. All patients attended the ENT outpatient Department, Rzgari Teaching Hospital, Erbil, Iraq. Two types of low-level laser therapy (LLLT) devices were used for patients. The first tool, a soft laser called a Tinnitool, has a wavelength of 660 nm and a power of 100 mW. The second tool is a Tinnitus Pen, which has a wavelength of 650 nm and a power of 5 mW. Seven females (77.7%) and two males (22.2%) participated in this study during one month. The mean age of the study sample was 44 years, with a standard deviation of 15.59 years. There was a significant improvement in the comparison of both types of therapy low-level laser before and after treatment, which reduced the tinnitus level among patients from 70% before treatment to 59% and 65.50%, respectively, after one month of treatment. A paired t test was applied to assess this difference before and after treatment. LLLT devices can be an effective device tool for the treatment of tinnitus and can reduce the symptoms of annoyance that affect the life of the sufferer. | The effectiveness of two types of low-level laser therapy in patients with persistent tinnitus | 10.1007/s10103-023-03797-z |
2023-06-02 | The frequency of extreme weather events has increased in the latest years in Europe. The recent consecutive droughts caused severe damage in many sectors and underlined the demand for adaptation. There is a need for a better understanding of the response of ecosystems to climate change and the consequences for key ecosystem services, such as water supply and carbon sequestration, at a local and regional scale. This paper aims to support decision-making for climate adaptation in a low-mountainous region of central Germany. We analysed the temperature and precipitation trends and drought conditions. The response of two key services (surface water provision and carbon sequestration) to droughts is estimated using an ecosystem service model. The spatially averaged water yield, net ecosystem productivity (NEP), and soil moisture are assessed and compared for the five worst droughts with long-term averages to identify the vulnerable areas and ecosystems. The temperature increased on seasonal and annual scales, while precipitation decreased in some areas in summer and increased in winter and annually. The standardised precipitation-evapotranspiration index (SPEI) showed worsening drought conditions, especially after the late 1980s. Droughts caused a reduction of water yield by 54%, NEP by 18%, and upper zone soil moisture by 13%. The impacts varied spatially, with the central region being worst affected, while the southern part was relatively more resilient. Adaptation is urgently needed to reduce drought risks and enhance climate resilience. Adaptive measures can include amending crop rotations, introducing more drought-tolerant varieties, upgrading agriculture and food industry technology, increasing mixed forests, and reducing non-native tree species. | Climatic drought impacts on key ecosystem services of a low mountain region in Germany | 10.1007/s10661-023-11397-1 |
2023-06-01 | Through the rapid carbonation test of SFRRC with different fiber volume fractions at ultra-low temperature, the influence of ultra-low temperature damage on the carbonation resistance of SFRRC was analyzed, which provides a theoretical basis for the application of SFRRC in ultra-low temperature engineering. The experimental results show that ultra-low temperatures can significantly weaken the carbonization resistance of SFRRC. When the temperature reaches 160 °C, the carbonization depth increases by 67.66 % compared with the normal state. The proper amount of steel fiber has an evident influence on the carbonation resistance of the material. However, when the addition amount exceeds the optimum content, the carbonation resistance of the material decreases. The grey prediction model established by constructing the original sequence can reasonably predict the carbonation resistance of SFRRC after ultra-low temperatures. | Effect of Ultra-low Temperature on Carbonation Performance of SFRRC and Prediction Model | 10.1007/s11595-023-2759-4 |
2023-06-01 | A computational study has been conducted to investigate the coupled effect of low temperatures and water saturation on the dynamic response of carbon/epoxy and E-glass/epoxy composite plates subjected to air blast and near-field explosive loading conditions. The temperature range considered corresponds to room temperature (20 °C) down to arctic seawater and extreme ocean depth conditions (− 2 °C). Each material has been evaluated in both dry and fully saturated conditions, with material properties taken from prior detailed mechanical evaluation studies. For the air-blast modeling, the study examined the transient elastic and damage response with both simply supported and fully fixed boundary conditions. The underwater explosive/blast modeling utilized fully clamped air backed plates which were loaded with an RP-503 explosive submerged in water. Finally, an evaluation of the effects of temperature/saturation coupling on the fundamental natural frequencies of the clamped plates was conducted. The results of the complete study show that plate responses to the dynamic loading conditions are dependent upon both the temperature and the saturation state. For each loading condition, the peak deformations are larger for panels, which are saturated with water, as compared to those in a dry state. Furthermore, panels evaluated at lower temperatures generally had lower displacements as compared to room temperature conditions. The study has shown that when considering composite materials, which will be subjected to shock loading in low temperature or wetted conditions, the material properties play a significant role in the transient and damage responses. | Effects of Low Temperature and Water Saturation on the Blast Response of Carbon and E-Glass Epoxy Composites | 10.1007/s40870-023-00373-y |
2023-06-01 | Vinblastine and catharanthine, mainly derived from Catharanthus roseus, are highly effective anticancer agents. With the increasing demand for Catharanthus roseus as their raw material, the cultivation gradually spread from south to north, in which planting and breeding are seriously affected by the cold climate in high-latitude regions. This study explores the effect of trehalose on C. roseus under low-temperature stress. Based on low-temperature stress experiments on C. roseus seedlings as the experimental material, it was discovered that exogenous application of trehalose effectively increased plant chlorophyll content and antioxidant enzyme activity. l -phenylalanine, quercetin, apigenin, chrysin and genistein accumulated significantly under low-temperature stress, by 115.3%, 91.6%, 125.7% and 123.6%, respectively, compared to CK, whereas the accumulation decreased after exogenous trehalose application. In addition, alkaloids production in C. roseus was inhibited. To further understand the effect of exogenous trehalose on alkaloids content, dynamic expression changes in the 4 enzyme genes involved in alkaloids metabolism were analyzed. In summary, CrSTR and CrSGD expression was significantly upregulated under low-temperature, while the expression of CrTDC and CrLAMT was downregulated. Exogenous trehalose significantly increased the expression level of all 4 genes. These findings revealed the positive regulation of trehalose on alkaloid metabolism in C. roseus . Consequently, this study provides a theoretical basis for low-temperature stress resistance improvement in C. roseus , suggesting exogenous trehalose applications in industrial production to promote the planting and breeding process. | Metabonomics Reveals the Mechanism of Trehalose Protecting Catharanthus roseus Against Low-Temperature | 10.1007/s00344-022-10833-9 |
2023-06-01 | Graphene-aerogel-based flexible sensors have heat tolerances and electric-resistance sensitivities superior to those of polymer-based sensors. However, graphene sheets are prone to slips under repeated compression due to inadequate chemical connections. In addition, the heat-transfer performance of existing compression strain sensors under stress is unclear and lacks research, making it difficult to perform real-temperature detections. To address these issues, a hyperelastic polyimide fiber/graphene aerogel (PINF/GA) with a three-dimensional interconnected structure was fabricated by simple one-pot compounding and in-situ welding methods. The welding of fiber lap joints promotes in-suit formation of three-dimensional crosslinked networks of polyimide fibers, which can effectively avoid slidings between fibers to form reinforced ribs, preventing graphene from damage during compression. In particular, the inner core of the fiber maintains its macromolecular chain structure and toughness during welding. Thus, PINF/GA has good structural stabilities under a large strain compression (99%). Moreover, the thermal and electrical conductivities of PINF/GA could not only change with various stresses and strains but also keep the change steady at specific stresses and strains, with its thermal-conductivity change ratio reaching up to 9.8. Hyperelastic PINF/GA, with dynamically stable thermal and electrical conductivity, as well as high heat tolerance, shows broad application prospects as sensors in detecting the shapes and temperatures of unknown objects in extreme environments. Graphical Abstract Polyimide fibers in graphene aerogel are in-suit welded to fabricate a composite with excellent hyperelasticity and adjustable thermal conductivity for artificial intelligence sensing over a wide temperature range. | Hyperelastic Graphene Aerogels Reinforced by In-suit Welding Polyimide Nano Fiber with Leaf Skeleton Structure and Adjustable Thermal Conductivity for Morphology and Temperature Sensing | 10.1007/s42765-023-00268-6 |
2023-06-01 | In order to improve the charge transfer rate and Li + diffusion coefficient of LiFePO 4 (LFP), the material was surface treated with polyacrylonitrile/polyaniline (PAN/PANI). PAN/PANI polymers were synthesized by a self-assembly process, and LFP@PAN/PANI were prepared by a wet-coating process. LFP@PAN/PANI exhibits superior electrochemical performance compared to bare LFP, with a discharge capacity of 3088.97 mAh at low temperature and high rate condition (−20 °C, 26650-type cylindrical battery, 5 C rate), and a relatively high low-temperature discharge plateau (2.68 V). Electrochemical impedance spectroscopy (EIS) proves that the Li + diffusion coefficient of LFP@PAN/PANI is an order of magnitude higher than that of bare LFP. The above performance is improved because the polar cyano group of the polymer can interact with the electrolyte and Li + , and the polyaniline makes the polymer have high conductivity. Therefore, the composite of the two polymers endows LFP with excellent Li + activity and high conductivity. | Influence of PAN/PANI polymer on low-temperature rate performance of LiFePO4 | 10.1007/s11581-023-04983-3 |
2023-06-01 | Aiming at high energy consumption and large Co loss in the pyrometallurgy of low-nickel matte, a process of NH 4 Cl roasting-water leaching was proposed to co-extract metals, followed by the separation and utilization of metals. The effect of several factors on metal extractions in NH 4 Cl roasting process and the optimized process conditions were investigated by orthogonal experiments. The most influencing factors were roasting temperature and NH 4 Cl dosage, and the optimized chlorination conditions were as follows: particle size of low-nickel matte <75 µm, roasting temperature of 500 °C, roasting time of 2.5 h, NH 4 Cl dosage of 250% and O 2 flow rate of 20 mL/min. By studying the effect of temperature and time on the extraction efficiency of metals, the appropriate leaching conditions were determined as temperature 90 °C and time 2 h. The extraction efficiency of nickel, copper, cobalt and iron can reach 97.6%, 96.2%, 94.5% and 29.2%, respectively. The (Ni, Cu, Co)Fe 2 O 4 photocatalyst was synthesized from leaching solution using α -Fe 2 O 3 as a carrier to composite with other metals. The optimum conditions were determined as precipitation temperature 25 °C and molar ratio of Ni-Cu-Co to Fe 1:3. The as-prepared catalysts were spherical nanoparticles of approximate 40–60 nm, and the degradation rate of which to methylene blue solution can reach 99.8% within 120 min. 针对低冰Ni 火法冶炼过程能耗高、Co 损失大的问题,本文提出了NH 4 Cl 焙烧-水浸联合提取金属,再分离利用金属的工艺。通过正交试验,研究了NH 4 Cl焙烧过程中不同因素对金属提取的影响,并确定了优化的工艺条件。结果表明,焙烧温度和NH 4 Cl用量为主要的影响因素,最佳氯化条件为: 低冰镍粒径<75 µm,焙烧温度500 ℃,焙烧时间2.5 h,NH 4 Cl用量250%,O 2 流速20 mL/min。通过研究温度和时间对金属浸出的影响,确定了适宜的浸出条件为: 温度90 ℃,时间2 h,这时Ni、Cu、Co和Fe 的浸出率分别达到97.6%、96.2%、94.5% 和29.2%。以浸出液为原料,以α-Fe 2 O 3 为载体与其他金属复合,合成了(Ni,Cu,Co)Fe 2 O 4 光催化剂。最佳制备条件确定为: 沉淀温度25 ℃,Ni-Cu-Co 与Fe 的摩尔比1: 3。制备的催化剂为40~60 nm 的球形纳米颗粒,在120 min 内对亚甲基蓝溶液的降解率可达99.8%。 | Extraction efficiency of metals from low-nickel matte via NH4Cl roasting-water leaching process and synthesis of (Ni,Cu,Co)Fe2O4 photocatalyst | 10.1007/s11771-023-5342-4 |
2023-06-01 | Achieving high strength and reliable bonding below 150°C using Ag nanoparticle pastes is still a challenge. This work developed an organic-free nano-Ag multilayer film consisting of a compact layer and a loose layer using pulsed laser deposition (PLD). A high shear strength of 71.2 MPa was achieved with bonding at 150°C, well above the reported values. A value of 18.6 MPa was achieved even with bonding at 50°C, meeting the MIL-STD-883 K standard requirement. The shear strength of sintered joints was strongly dependent on the diffusion behavior and microstructure evolution of loose layers. The sub-10-nanometer grains and high quantity of lattice disorders in the Ag nanoparticles induced a high diffusion driving force, ensuring high-strength bonding inside the bondline. In addition, pre-bonding and nano-bump effects of the deposited compact layer enhanced the interfacial bonding between bondline and metalized surfaces. This work provides a promising method for robust die attachment below 150°C. | Bonding Below 150°C Using Nano-Ag Film for Power Electronics Packaging | 10.1007/s11664-023-10358-1 |
2023-06-01 | Background Saussurea involucrata (Sik.) is alpine plant that have developed special adaptive mechanisms to resist adverse environmental conditions such as low temperature chilling during long-term adaptation and evolution. Exploring the changes of its metabolites under different temperature stresses is helpful to gain insight into its cold stress tolerance. Methods Ultra-performance liquid chromatography and tandem mass spectrometry were used to analyze the metabolites in the leaves of Sik . under low different temperature stress conditions. Results: A total of 753 metabolites were identified, and 360 different metabolites were identified according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) involved in the biosynthesis of secondary metabolites and amino acids and sugars. Sucrose and trehalose synthesis, glycolysis, tricarboxylic acid cycle, pentose phosphate pathway, glutamic acid-mediated proline biosynthesis, purine metabolism, amino acid metabolism, phenylpropane synthesis pathway metabolites all respond to low temperature stress. Under cold stress conditions, carbohydrates in Sik . leaves accumulate first than under freezing conditions, and the lower the temperature under freezing conditions, the less amino acids accumulate, while the phenolic substances increase. The expression of various substances in LPE and LPC increased more than 10-fold after low temperature stress compared with the control, but the content of LPE and LPC substances decreased after cold adaptation. In addition, purines and phenolics decreased and amino acids accumulated significantly under freezing conditions. Conclusion: The metabolic network of Sik . leaves under different low temperature stress conditions was proposed, which provided a reference for further exploration of the metabolic mechanism related to low temperature stress tolerance of Sik . | Metabolomics-based exploration the response mechanisms of Saussurea involucrata leaves under different levels of low temperature stress | 10.1186/s12864-023-09376-4 |
2023-06-01 | Membrane distillation (MD) is a sustainable approach for the treatment of challenging saline water by effective removal of non-volatile compounds at high water recovery, offering near-to-zero liquid discharge to environment. Progressive efforts have been made in recent literature to mitigate membrane fouling and enhance the wetting resistance of MD for long-term stable operation; however, extensive energy consumption is the key constraint that hinders MD to become an economically sustainable solution for industrialization. This review represents the evaluation of energy consumption in MD in comparison with other existing advanced water treatment technologies (e.g., reverse osmosis). An up-to-date review of low-energy MD utilization to minimize energy consumption is provided in this work. High energy consumption in MD can be compensated by the effective utilization of renewable energy sources such as solar energy, geothermal energy, or waste heat. However, due to the sporadically unequal distribution and unstable availability of these low-grade sources, the dependence on the abundance of these energy sources may limit the flexibility in commercial MD applications. A recent approach to reduce specific thermal energy through direct heating of the membrane or spacer is also discussed in this review. The development of the membrane materials/configurations was highlighted for mitigating the effects of temperature polarization and improving energy efficiency by localized heating at/near the membrane surface by using photothermal, electrothermal, or induction materials. | Mitigation of Thermal Energy in Membrane Distillation for Environmental Sustainability | 10.1007/s40726-023-00249-8 |
2023-06-01 | To study the modification mechanism of activated carbon (AC) by Fe and the low-temperature NH 3 -selective catalytic reduction (SCR) denitration mechanism of Fe/AC catalysts, Fe/AC catalysts were prepared using coconut shell AC activated by nitric acid as the support and iron oxide as the active component. The crystal structure, surface morphology, pore structure, functional groups and valence states of the active components of Fe/AC catalysts were characterised by X-ray diffraction, scanning electron microscopy, nitrogen adsorption and desorption, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The effect of Fe loading and calcination temperature on the low-temperature denitration of NH 3 -SCR over Fe/AC catalysts was studied using NH 3 as the reducing gas at low temperature (150 °C). The results show that the iron oxide on the Fe/AC catalyst is spherical and uniformly dispersed on the surface of AC, thereby improving the crystallisation performance and increasing the number of active sites and specific surface area on AC in contact with the reaction gas. Hence, a rapid NH 3 -SCR reaction was realised. When the roasting temperature remains constant, the iron oxide crystals formed by increasing the amount of loading can enter the AC pore structure and accumulate to form more micropores. When the roasting temperature is raised from 400 to 500 °C, the iron oxide is mainly transformed from α -Fe 2 O 3 to γ -Fe 2 O 3 , which improves the iron oxide dispersion and increases its denitration active site, allowing gas adsorption. When the Fe loading amount is 10%, and the roasting temperature is 500 °C, the NO removal rate of the Fe/AC catalyst can reach 95%. According to the study, the low-temperature NH 3 -SCR mechanism of Fe/AC catalyst is proposed, in which the redox reaction between Fe 2+ and Fe 3+ will facilitate the formation of reactive oxygen vacancies, which increases the amount of oxygen adsorption on the surface, especially the increase in surface acid sites, and promotes and adsorbs more reaction gases (NH 3 , O 2 , NO). The transformation from the standard SCR reaction to the fast SCR reaction is accelerated. | Low-temperature Denitration Mechanism of NH3-SCR over Fe/AC Catalyst | 10.1007/s11595-023-2721-5 |
2023-06-01 | Two-dimensional (2D) materials such as graphene and MoX 2 (X = S, Se, W, Te) are very important for the next-generation electronic devices. One of the most exciting materials in 2D materials is MoS 2 and the most important property that MoS 2 has, but graphene does not have, is the bandgap. For obtaining good quality of MoS 2 film, the selection of Mo precursor and S source is very important. And the other experimental conditions, such as synthesis temperature and reaction gas flow rate, are also important for obtaining good quality of MoS 2 thin film, particularly at low temperature. Synthesis of MoS 2 at the high temperature above 500 °C is relatively easy for the researchers. However, the synthesis of MoS 2 at the low temperature is not easy. In this work, we will report on the experimental results of MoS 2 synthesis carried out on SiO 2 (300 nm)/Si substrate at low temperature of 200 °C and 300 °C with precursor of Mo(CO) 6 . Even at the very low temperature of 200 °C, we could synthesize relatively good quality of MoS 2 films. | Low-temperature synthesis of MoS2 at 200 °C | 10.1007/s40042-023-00831-9 |
2023-06-01 | Abstract The review describes low-temperature reduction of (–)-mentholactone with diisobutylaluminum hydride in methylene chloride. Depending on the conditions, three products are formed: (2 S ,4 R ,7 S )-7-isopropyl-4-methyloxepan-2-ol [(–)-mentholactol), (6 R )-8-hydroxy-2,6-dimethyloctan-3-one, and (2 S ,4 R ,7 S )-2-isobutoxy-7-isopropyl-4-methyloxepane. Possible ways of formation of each product have been proposed, and conditions for their selective formation have been found. The synthesis of oxepan-2-ol isobutyl acetals via low-temperature (–70°C) reduction of 7-membered lactones with diisobutylaluminum hydride in methylene chloride is considered. The synthesis of a number of low-molecular-weight bioregulators, including optically active pheromones of insect pests in agriculture and forestry, based on (–)-mentholactol, its aluminate, and (6 R )-8-hydroxy-2,6-dimethyloctan-3-one is discussed. | Transformations of Seven-Membered Terpene Lactones toward Low-Molecular-Weight Bioregulators | 10.1134/S1070428023060015 |
2023-06-01 | Selective catalytic reduction (SCR) system is considered to be the most effective control method for reducing NO x in exhaust gas post-treatment of the diesel engine. Catalysts are the main factors affecting de-NO x efficiency in SCR reactions. In recent years, due to the excellent characteristics of copper zeolite catalysts, they have been widely studied as low-temperature NH 3 -SCR catalysts. However, the development of low-temperature SCR catalysts with high removal efficiency still faces severe challenges. This paper reviewed the latest research progress with copper zeolite catalysts at low temperature and compared the action mechanism of various copper zeolite catalysts in NH 3 -SCR reactions. Copper zeolite catalysts were studied from the aspects of catalytic performance, preparation strategy, broadening the operating temperature window, hydrothermal deactivation and resistance to H 2 O and SO 2 . Several solutions to the problems existing in low-temperature NH 3 -SCR reactions were discussed. In addition, this paper also puts forward some views on the future research direction of copper zeolite catalysts. Finally, the summaries and prospects of the development of low-temperature SCR copper zeolite catalysts were presented. Hopefully, more researchers can understand the current research status of copper zeolite catalysts and obtain better research achievements from copper zeolite catalysts in the future. This review could pave the way for similar studies to enable a wider variety of copper zeolite catalysts to be commercially available. Graphical abstract | Research progress on selective catalytic reduction of NOx by NH3 over copper zeolite catalysts at low temperature: reaction mechanism and catalyst deactivation | 10.1007/s11164-022-04938-9 |
2023-06-01 | Mechanical behavior and deformation essence of frozen soft rock under complex environmental conditions is crucial for frozen shaft engineering. The strength and deformation properties of sandstones under different low temperatures were investigated by conducting uniaxial and triaxial compression tests. The energy characteristics of rocks during the deformation were analyzed. The micro-structure features were obtained by scanning electron microscopy (SEM) test. The results show that the sandstones have a noticeable pore compression stage and the medium-grained sandstone is more pronounced. The rock strength decreases and increases non-linearly with the increase of temperature and confining stress, respectively, and the factors affect each other. The elastic modulus increases with the decrease of low temperature, while the changes in Poisson ratio is opposite. In addition, the total strain energy, elastic energy and dissipated energy of sandstones have different evolution laws, revealing the deformation and damage mechanism of rocks. Last, the internal reason of differences in the mechanical properties of sandstones is explained from the microstructural perspective. The above research conclusions could provide a certain theoretical basis for the stability control of shaft engineering in northwest China. 复杂地应力和低温环境条件下白垩系弱胶结红砂岩的力学特性和变形本质是西北地区冻结井筒 工程安全建设的关键。通过低温单轴和三轴压缩试验, 研究了不同低温、不同围压条件下饱和白垩系 粗粒砂岩和中粒砂岩的强度和变形特性, 查明了冻结砂岩加载变形过程中的能量演化规律和影响因 素, 并基于扫描电镜(SEM)揭示了两种砂岩的微观结构特征。结果表明: 冻结白垩系砂岩的应力−应变 关系呈应变软化型, 其受温度、围压和岩性的影响显著, 具有明显的孔隙压密变形阶段; 冻结砂岩的 三轴压缩强度随着温度和围压的增加分别呈非线性减小和增大规律, 且各因素之间相互影响。两种砂 岩的弹性模量随着温度的降低而非线性增大, 但泊松比的变化与之相反。此外, 冻结白垩系弱胶结红 砂岩的总应变能、弹性能和耗散能具有不同的演化规律, 揭示了冻结砂岩的变形破坏内部机制; 基于 能量比提出了冻结砂岩的损伤因子, 评价了两种冻结砂岩的损伤力学特征。最后, 从宏观物理特性和 微观结构特征等多角度解释了两种砂岩力学和能量特性差异的内在原因。研究成果将为我国寒区矿山 建设和深部地下工程的稳定性控制提供理论依据。 | Mechanical properties and energy-dissipation mechanism of frozen coarse-grained and medium-grained sandstones | 10.1007/s11771-023-5344-2 |
2023-06-01 | The application of biomass pyrolysis was still limited owing to the high pyrolysis temperature and the complicacy of pyrolysis products. In this work, a homogeneous low-temperature cellulose catalytic pyrolysis system is proposed to directional products 5-methylfurfural. The low-temperature catalytic activity and products distribution of cellulose pyrolysis in [bmim][FeCl 4 ] (Fe-IL) and [bmim] 2 CoCl 4 (Co-IL) at temperature gradients from 150 to 300 °C were studied. As the results, both Fe-IL and Co-IL can catalyze the pyrolysis of cellulose, especially for Fe-IL, which effectively reduced the pyrolysis temperature of cellulose to 200 °C. Nano-scale and micron-scale particles were produced by the catalysis of Fe-IL and Co-IL, respectively. Fe-IL have a high selectivity for the production 5-methylfurfural (5-MF) and furfural (FF), which were 71.12% and 19.14% respectively at the pyrolysis temperature of 200 °C. Furthermore, the mechanism of low-temperature catalytic pyrolysis and the directional evolution mechanism of 5-MF and FF were suggested. Graphical abstract | Low-Temperature Catalytic Pyrolysis of Cellulose to Directional Products 5-Methylfurfural by Magnetic Ionic Liquid | 10.1007/s12155-022-10494-2 |
2023-06-01 | In this paper, low-grade limonitic nickel laterite and chromite were synergistically utilized via the hybrid sintering process (i.e., pellet-sintering process) for high-quality Ni–Cr sinter preparation and great carbon emission reduction. Under the optimum process conditions, Ni–Cr sinter indices were substantially improved in the pellet-sintering process. Tumble index and productivity were improved by 33.57% and 27.84%, respectively, and solid fuel rate was reduced by 16.02% compared with the base case. CO 2 emissions can be annually reduced by 112.62 thousand tons in sinter production for a major Chinese stainless steel enterprise. This was due to that the better heat and mass transfer conditions during pellet-sintering was beneficial to the reduction of sinter porosity and the formation of silico-ferrite of calcium and alumina, which consequently contributed to the generation of Ni–Cr sinter with more compact microstructure at lower solid fuel consumption. Its reduction characteristics were similar to the base case whereas the softening-melting properties were even better. In addition, Fe–Cr–Ni crude alloy formed in the determination process of softening-melting properties possessed the appropriate melting point, which was suitable for blast furnace production. The high-quality Ni–Cr sinter obtained from the low-carbon pellet-sintering process can be used as the qualified burden for Fe–Cr–Ni alloy smelting at lower cost. Graphical Abstract | Reduction of Carbon Footprint Through Hybrid Sintering of Low-Grade Limonitic Nickel Laterite and Chromite Ore | 10.1007/s40831-023-00676-3 |
2023-06-01 | Lithium-sulfur (Li-S) batteries have demonstrated the potential to conquer the energy storage related market due to the extremely high energy density. However, their performances at low temperature are still needed to be improved to broaden their applications. Therefore, in this review, the basic failure mechanisms and major challenges of Li-S battery at low temperature are categorized as the high desolvation barrier of Li + , uncontrolled nucleation and deposition of lithium, polysulfides clustering, and passivation of cathode by film like Li 2 S. Targeting these major issues, strategies, and advances concerning the design of optimized electrolyte, composite cathode and functional separator are highlighted and discussed. Finally, the suggestions are proposed for the future development of practical Li-S battery working at low temperature scenarios, hoping to accelerate the commercialization process and bring revolution to the energy storage market. | Challenges and advances on low-temperature rechargeable lithium-sulfur batteries | 10.1007/s12274-022-4983-1 |
2023-06-01 | Melatonin (Mel) and CaCl 2 have been demonstrated to play significant roles in plant cold tolerance. However, studies on their mechanisms of action are relatively limited. In this study, the effects of Mel and CaCl 2 on the growth of cucumber seedlings under low-temperature stress (10 °C/6 °C, day/night) and the possible interplay between Mel and CaCl 2 in this process were investigated. The results indicated that Mel and CaCl 2 at different concentrations inhibited low-temperature-induced reactive-oxygen species burst and decreased lipid peroxidation levels when compared with low-temperature stress alone, with the most significant effects being observed in the treatment with 100 μM Mel and 10 mM CaCl 2 ( P < 0.05). The foliar application of 100 μM Mel and 10 mM CaCl 2 also increased the accumulation of osmoprotective compounds in different organs and the root vigor of cucumber seedlings under low-temperature conditions. However, the above favorable effects of Mel and CaCl 2 were significantly negated by the combined treatment of p-chlorophenylalanine (p-CPA, inhibitor of Mel biosynthesis) with Mel and that of lanthanum chloride (LaCl 3 , Ca 2+ channel blocker), ethylene glycol tetraacetic acid (EGTA, Ca 2+ chelator), trifluoperazine dihydrochloride (TFP, calmodulin antagonist and CDPK inhibitor), or N -(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7, calmodulin antagonist and CDPK inhibitor) with CaCl 2 . Furthermore, increased photosynthetic efficiency (confirmed by chlorophyll fluorescence parameters) and expression levels of photosynthesis-related genes ( Rbc L , Rbc S , RCA , FBPase , and SBPase ) were observed in cucumber seedlings pretreated with Mel and CaCl 2 under low-temperature stress. Intriguingly, co-treatment of LaCl 3 /EGTA or TFP/W-7 with Mel significantly attenuated the effects of Mel on the growth and photosynthesis of cucumber seedlings under low-temperature stress. In contrast, p-CPA had slight or no effect on the growth and photosynthesis by CaCl 2 . These results suggested that Mel and CaCl 2 could improve the cold tolerance of cucumber seedlings by maintaining redox homeostasis and osmotic balance and improving photosynthetic efficiency. In addition, Mel confers cold tolerance to cucumber seedlings in a Ca 2+ signaling (Ca 2+ /CDPKs and Ca 2+ /CaM)-dependent manner. In conclusion, this study revealed the positive regulatory effects of exogenous Mel and CaCl 2 on the cold tolerance of cucumber seedlings and their interactions during this process. This work could also promote the application of these two substances in agriculture and provide a reference for the study of their mechanisms of action. | Exogenous Melatonin and CaCl2 Alleviate Cold-Induced Oxidative Stress and Photosynthetic Inhibition in Cucumber Seedlings | 10.1007/s00344-022-10805-z |
2023-06-01 | Magnetization roasting is one of the most effective way of utilizing low-grade refractory iron ore. However, the reduction roasting of siderite (FeCO 3 ) generates weakly magnetic wüstite, thus reducing iron recovery via weak magnetic separation. We systematically studied and proposed the fluidized preoxidation-low-temperature reduction magnetization roasting process for siderite. We found that the maghemite generated during the air oxidation roasting of siderite would be further reduced into wüstite at 500 and 550°C due to the unstable intermediate product magnetite (Fe 3 O 4 ). Stable magnetite can be obtained through maghemite reduction only at low temperature. The optimal fluidized magnetization roasting parameters included preoxidation at 610°C for 2.5 min, followed by reduction at 450°C for 5 min. For roasted ore, weak magnetic separation yielded an iron ore concentrate grade of 62.0wt% and an iron recovery rate of 88.36%. Compared with that of conventional direct reduction magnetization roasting, the iron recovery rate of weak magnetic separation had greatly improved by 34.33%. The proposed fluidized preoxidation-low-temperature reduction magnetization roasting process can realize the efficient magnetization roasting utilization of low-grade refractory siderite-containing iron ore without wüstite generation and is unlimited by the proportion of siderite and hematite in iron ore. | Fluidized magnetization roasting of refractory siderite-containing iron ore via preoxidation–low-temperature reduction | 10.1007/s12613-022-2576-3 |
2023-06-01 | Haptophytes are emerging as sustainable sources of high-value metabolites such as polyunsaturated fatty acids (PUFAs). The goal of this work was to isolate a native haptophyte from the southwestern Atlantic coast and to evaluate the effect of low-temperature stress on the concentration of PUFAs, sterols, and pigments during its cultivation. The strain was identified as Pavlova gyrans . Cultures were carried out in a photobioreactor for 10 days at 20 °C (Control), lowering the culture temperature to 10 °C at the beginning of the stationary growth phase (LTS). The lipid content of the biomass represented 13% of the dry weight, neutral lipids being the main lipid fraction. Under LTS, biomass increased significantly, reaching a value of 305 mg L −1 . The same effect was observed with PUFAs content, which represented 41.3% of total fatty acids. The most abundant omega-3 (ω3) and omega-6 (ω6) fatty acids were eicosapentaenoic (EPA) and docosapentaenoic (DPA), respectively. PUFAs concentration under LTS reached 6.65 mg L −1 of which 3.59 mg L −1 corresponded to ω3 and 3.06 mg L −1 to ω6. EPA reached a value of 2.82 mg L −1 while that for DPA was of 1.59 mg L −1 . The maximum content of phytosterols was obtained during the exponential growth phase. The most abundant phytosterol was 24-ethylcholesta-5,22-dien-3β-ol, which represented ≈41–49% of the free sterol fraction, with a volumetric concentration of ≈320 μg L −1 . Finally, under LTS pigments reached a value of ≈700 μg L −1 . These results open the way for further progress towards the commercial and profitable cultivation of P. gyrans for food and aquaculture applications. | Pavlova gyrans as a potential source of essential fatty acids, sterols and pigments: culture under low temperature | 10.1007/s10811-023-02943-y |
2023-06-01 | Low-cycle fatigue (LCF) behavior of the directionally solidified (DS) nickel-based DZ125 superalloy was studied at elevated temperature (980 °C). Specimens were, respectively, exposed for 0, 2, 25, 50, and 100 h in air. The fatigue life of pre-exposed specimens is lower than that of unexposed specimens. The result is closely associated with fatigue crack initiation and propagation due to oxygen embrittlement and cycle loading. Detailed fractographic evaluations indicate the fatigue life is closely related to the surface microstructural modification. The resulting changes in microstructure cause the decrease in the effective area and the increase in actual stress. A methodology based on the continuum damage mechanics is developed to describe the correlation between the residual LCF life and pre-exposed time. | Low-cycle fatigue behavior of DZ125 superalloy under prior exposure conditions | 10.1007/s12598-016-0874-5 |
2023-06-01 | In this study, the microstructural evolutions, phase equilibrium, mechanical properties and fracture mechanism of hot-rolled and post-weld solution-treated Fe-12.5Mn-9.8Al-1.0C(wt.%) low-density steel welded joints were investigated. Optical microscopy (OM), scanning electron microscope (SEM), eelectron backscatter diffraction (EBSD) and x-ray diffraction (XRD) were used to analyze microstructure and phases of the weld metal. Tensile test and microhardness test were inspected to determine the mechanical properties. Tensile fracture morphology was also determined by SEM. The results illustrated that welded joint was composed of austenite and annealing twins. Compared with the hot-rolled experimental steel, the strength and hardness of the post-weld solution-treated steel were reduced, but the elongation was increased. Especially, when the solution temperature was 950 °C, the elongation increased to 10.6%, which improved the plasticity and the quality of the welded joint. | The Microstructure and Mechanical Properties of Welded Joints of Hot-Rolled and Post-Weld Solution-Treated Fe-12.5Mn-9.8Al-1.0C Low-Density Steel | 10.1007/s11665-022-07455-3 |
2023-06-01 | Low-temperature combustion in diesel engines gained prominence because of their ability to meet the current emission standards without NOx and PM trade-off. Among the low-temperature combustion concepts, premixed charge compression ignition (PCCI) offers an in-cylinder emission reduction with minimal to zero engine modifications. This work reviews the role of premixed charge compression ignition (PCCI) of low-carbon and oxygen-rich fuels on diesel powertrains' performance. This review covers the fundamentals and significance of PCCI combustion with low-carbon oxygen-rich fuels of both renewable and synthetic origins. Various strategies employed for achieving PCCI combustion, in-cylinder, and external charge preparation are discussed in this review. The effect of a single injection, multiple split injections, injection pressure, and injection duration on PCCI combustion in diesel engines is discussed at length. Low-temperature combustion depends on the chemical kinetics of combustion. The present review discusses the numerical works carried out with detailed chemical kinetics of various conventional and alternative fuels. Challenges in PCCI combustion, such as wall-wetting in early direct injections, combustion phasing, narrow load range, and engine knock for conventional and unconventional fuels, are presented. Bottlenecks in the present PCCI technology, advantages of using alternative fuels for PCCI combustion, and the scope of future work are presented at the end of this review. Graphic abstract | PCCI combustion of low-carbon alternative fuels: a review | 10.1007/s10973-023-12108-1 |
2023-06-01 | The demand for cold-resistant coatings that can be applied at low temperatures is rapidly growing, especially for polar cables requiring extreme cold resistance. These cables also need extreme cold resistance and organic solvent-free or water-dispersion coating resins that do not produce volatile organic compounds. In the current study, to address these issues, waterborne poly(dimethylsiloxane)-appended polyurethane (WPU-PDMS) resins were prepared. FTIR measurements confirmed the structures of the WPU-PDMS copolymers, and EDS mapping images established the presence of the siloxane group. DSC and TGA measurements showed that WPU-S10, with a PDMS-based polyol molar ratio of 10%, had a low glass transition temperature and high thermal stability. WPU-S10 also exhibited a high UV blocking rate and exceptional light resistance. Moreover, WPU-S10 displayed outstanding low-temperature characteristics, including a tensile strength of 1.31 kg/mm 2 , elongation of 190%, and a shape recovery rate of 90% at – 40 ℃. It is evident that the PDMS content contributed to the chain flexibility, significantly increasing low-temperature elongation. Finally, WPU-S10 revealed no deep cracks on the surface after cold bending, demonstrating excellent low-temperature characteristics and cold resistance. Exceptional low-temperature characteristics and cold resistance of WPU-PDMS provide an ideal coating solution for various applications in Arctic conditions. | Low-Temperature Flexible WPU-PDMS Copolymers for Cold-Resistant Coating Applications | 10.1007/s12221-023-00227-3 |
2023-06-01 | The superconductivity and nontrivial topological electronic state are key hallmarks of topological superconductors. Here, we focus on the transport signals of possible topological surface state in the topological superconductor candidate β-PdBi 2 nanoflake with a thickness of 21 nm. The resistance demonstrates a semiconductor-metal transition followed by an upturned behavior as the temperature decreases. A large and unsaturated longitudinal magnetoresistance (MR), accompanied by distinct Shubnikov-de Hass oscillation in Hall resistance, is observed. An analysis of Hall resistance reveals that the carriers present the characteristics of relativistic particles with small effective mass and extremely high mobility. The angle-dependent quantum oscillations demonstrate a two-dimensional Fermi surface topology. A giant anisotropic MR as large as 98% is detected when rotating the magnetic field. These results provide the possible transport signals of a nontrivial topological electronic state, establishing a further understanding of the topological properties of the low-dimensional topological superconductor candidate α-PdBi 2 . | Transport signatures of the topological surface state induced by the size effect in superconductor β-PdBi2 | 10.1007/s11433-023-2103-2 |
2023-06-01 | The accumulation of heavy metals in water bodies degrades the water quality and availability. Heavy metals are toxic and can be fatal if consumed. Various techniques such as ion-exchange, precipitation, and adsorption have been used to extract heavy metals in wastewater. The process of adsorption will be reviewed in this study since it uses various adsorbents from industrial waste to agricultural waste and is inexpensive. The production of adsorbents from industrial waste produces large amounts of toxins such as greenhouse gases and it is also costly to produce; thus, it was suggested that adsorbents are produce using biomass, which supports both circular economy and sustainability. The most effective biomass adsorbent is activated carbon; however, it has high production costs than biochar. This study will review on synthesis of biochar, its contribution to circular economy, biochar adsorption mechanisms, heavy metals extraction techniques, and peanut shells as an effective adsorbent to extract heavy metals, namely, chromium, cadmium, lead, zinc, and copper and as a low-cost adsorbent. Furthermore, limitations to using peanut shell-derived biochar are identified. Studies were conducted using peanut shells and it was found that even using peanut shell without pyrolysis is effective to remove heavy metals. In one study, raw peanut shells (non-pyrolyzed) were used to extract lead and the peanut shells’ dosages were at 0.5 g, 1.0 g, and 1.5 g and it was found that 74.36%, 74.57%, and 74.05% of lead was extracted, respectively. In other study, the peanut shells were pyrolyzed to produce biochar and used to extract Cr(I II), Cu(II), and Pb(II) and it was found that it extracted 80%, 85%, and 90% of the metal ions, respectively. This shows that biochar adsorbs more heavy metal ions; thus, it is necessary to thermally degrade the biomass before usage. More literature on the usage of peanut shells to extract heavy metals in wastewater are reviewed in this article to further show that peanut shells have potential to be used as an adsorbent. | Peanut Shell-Derived Biochar as a Low-Cost Adsorbent to Extract Cadmium, Chromium, Lead, Copper, and Zinc (Heavy Metals) from Wastewater: Circular Economy Approach | 10.1007/s43615-022-00207-4 |
2023-06-01 | One of the seismic retrofit methods is applying heat to transfer the failure location from the near column into the beam. In this method, by heating a section of the beam, changes the mechanical characteristics of the beam, such as enhancing the ductility and decreasing the yield as well as the ultimate strength in that section, thus causing an altered place of failure as well as changes in the failure mode. In this study, via experimental and numerical methods an investigation was conducted on the ultra-low cycle fatigue capacity in retrofitted St-37 steel connection with three models of thermal improvement with the titles HBS1, HBS1&RIB, and HBS2 which differ in the cooling rate after the heating operation. The connection without retrofit failed in the cycle of 5% drift angle of SAC protocol loading. Retrofitted connections with HBS1 and HBS1&RIB thermal models failed in the cycle of 6% drift angle of SAC protocol loading. The results of modeling these connections in software and using the ultra-low cycle fatigue failure index also revealed a failure in a cycle with a 6% drift angle. The seismic capacity of the retrofitted connection with the HBS2 thermal model, with one percent increase in seismic capacity, failed in the cycle of 7% of the drift angle. The result of numerical modeling of this connection in the software was the same and indicated the ultra-cycle fatigue failure occurring in the cycle of 7% of the drift angle. | Experimental Investigation on Ductile Failure in Heat Retrofitted Connections by Ultra-Low Cycle Fatigue Method | 10.1007/s13296-023-00712-8 |
2023-06-01 | Abstract This article reviews the main properties of the modular design of small nuclear power plants (SNPPs), shows the possibility of reducing the cost and construction time of this class of plants through factory production, the effect of serialization, and the reduction of redundant safety systems. The prospects for significant expansion of the field of application of nuclear technologies due to their modularity and the possibility to ensure high safety performance are presented. Possible areas of SNPP use for power supply of remote territories including the Arctic area, production of high-potential heat and hydrogen for industrial consumers, and other applications are analyzed. It shows the need to develop and implement a new nuclear energy technology platform based on SNPPs to solve the problems of global decarbonization of the world economy by significantly expanding the scope of nuclear energy technologies in addition to the currently developed technological platform of a closed nuclear fuel cycle with fast neutron reactors and the technological platform of controlled thermonuclear fusion. The authors propose to create a pilot site for testing technologies for captive production of hydrogen (heat) for an industrial consumer, as well as other technologies for the utilitarian use of SNPPs based on a pilot demonstration of a nuclear power plant with a high-temperature (about 1100°C) fast neutron reactor with a gas coolant. | Prospects for the Development of Small Nuclear Power Plants in Russia | 10.1134/S1019331623010136 |
2023-06-01 | The subject of this study was the application of a novel CO 2 -based low-molecular weight poly (propylene carbonate) diol (PPCD) in the field of adhesive. Two-component polyurethane adhesive (PPCD-PU) was prepared with PPCD and polymethylene polyphenyl polyisocyanate (PAPI) as raw materials, propylene carbonate diol (PCD-EDA) as extender. The effects of the molecular weight, carbonate linkage content of PPCD and content of PCD-EDA on the properties of PPCD-PU were also investigated. The results showed that the novel CO 2 -based low-molecular weight poly (propylene carbonate) diol had higher carbonate linkage content (35%). The PPCD-PU synthesized by the PPCD had good adhesion performance, and the lap shear strength reached to 15 MPa. The addition of PCD-EDA not only improved the bonding properties of the adhesive, but also made PPCD-PU adhesive achieved higher lap shear strength in a shorter curing time. When the amount of PCD-EDA was 20 wt.%, the lap shear strength increased to 17 MPa, and the lap shear strength increased significantly from 3.7 to 10.6 MPa after curing at 80 °C for 30 min. Water absorption rate of PPCD-PU film was about 1.7%, and the lap shear strength was almost unchanged after 24 h of immersion in water. The temperature of 5%-weight loss of PPCD-PU was 284 °C, and the glass transition temperature was 79.3 °C. All the polyurethane adhesives obtained performed good heat and water resistance. | Novel CO2-based low-molecular weight poly (propylene carbonate) diol (PPCD) for two-component polyurethane adhesive | 10.1007/s11696-023-02708-4 |
2023-06-01 | The development of a realistic numerical model that predicts the impact behavior of adhesively bonded composite joints is important for many industrial sectors such as automotive, aerospace, and marine. In this study, it was aimed to develop a numerical model that can predict the low-velocity oblique impact behavior of composite single-lap joints close to the experimental results. The validation of the proposed numerical model was carried out with the results of the previously experimentally tested joints. In explicit finite element analysis, the orthotropic material model and Hashin’s damage criterion were used in the numerical model of composite adherends. The adhesive region was divided into three different regions. The cohesive zone model (CZM) was used to determine the damage initiation and propagation in the upper and lower interface regions of adhesive. The middle region of the adhesive between the two cohesive interfaces was modeled with an elastic–plastic material model to reflect the plastic material behavior of the adhesive in the analysis. The effects of impact angle, fiber orientation, and overlap length on adhesive damage initiation and propagation were investigated in detail. There is a good agreement between the numerical and experimental results, considering the contact force-time variations and composite and adhesive damage. The impact angle and fiber angle had a significant effect on the impact behavior of the composite joints and the adhesive damage initiation and propagation. The increase in impact angle and fiber angle caused a decrease in the maximum contact force value. Adhesive damage propagation patterns varied according to the composite fiber orientation. In addition, since the shear toughness of the adhesive is higher than its tensile toughness, the amount of adhesive damage and damage propagation rate decreased as the impact angle increased. | Finite Element Analysis of Low-Speed Oblique Impact Behavior of Adhesively Bonded Composite Single-Lap Joints | 10.1007/s10443-023-10119-7 |
2023-06-01 | Abstract Low-temperature combustion synthesis was used both for modifying silica gel support with 10 and 20 wt % Al 2 O 3 and for producing supported catalysts with 10 wt % of Co active phase. Prepared catalysts were characterized by XRD, SEM, EDS, and BET method. It was revealed that these catalysts contain oxides, aluminates, and silicates of cobalt. It was shown that modification of support noticeably reduces its specific surface, while its calcination decreases the catalyst activity. The catalysts synthesized from supports with lower content of Al 2 O 3 demonstrated higher specific surface and lower activity in deep oxidation of propane and CO. The catalyst on an uncalcinated support modified with 20 wt % Al 2 O 3 was found to possess the highest activity in the process of deep oxidation. | Low-Temperature Combustion Synthesis and Characterization of Co-Containing Catalysts Based on Modified Silica Gel | 10.3103/S1061386223020024 |
2023-06-01 | This study reports on the investigation of the melting behavior and mechanical properties of Sn–Bi–In ternary solders, which has two ternary eutectic points (59 °C and 76 °C), with six different compositions chosen from the liquidus line from the In–Sn eutectic point (118 °C) to the ternary eutectic point at 59 °C. We fabricated solder pastes with the compositions and characterized them using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), shear test, and solder balling test. The solder balling test disclosed that the solders with a wide pasty zone (T liquidus −T solidus ) and a wide exothermic peak showed a poor morphology after solder balling test, while those with a composition close to the binary or ternary eutectic compositions exhibited a good morphology. The SEM analysis disclosed that the ternary solders were comprised of β-InSn, γ-InSn, and BiIn 2 , and that the volume fraction of BiIn 2 increased as the composition moves toward the ternary eutectic point. The shear test unfolded that the microstructure change influenced the fracture mode, which changed from ductile to brittle possibly due to the increase of the phase fraction of BiIn 2 . The shear strength was around 18 MPa for the In–Sn binary solder and was between 22 and 24 MPa for the ternary alloy samples. | Investigation of Sn–Bi–In ternary solders with compositions varying from In–Sn eutectic to 59 °C ternary eutectic point | 10.1007/s40042-023-00788-9 |
2023-06-01 | The reservoir properties and gas-bearing characteristics of different lithotypes of lignite are different, resulting in complex migration and accumulation laws of methane in lignite. Following systematic collections of samples of different lithotypes from the Erlian Basin, occurrence modes and storage potential of methane in lignite were explored through a series of isothermal adsorption experiments and NMR-based experiments on original water-containing samples. The maceral composition affects the reservoir characteristics and hydrophilicity of different lithotypes of lignite, which control the reservoir’s gas–water competition. Xylite lignite has a strong adsorption capacity, poor development of macropores, and high irreducible water content. Therefore, among various lithotypes of lignite, xylite lignite has the highest occurrence potential for adsorbed gas and soluble gas and the lowest potential for free gas. Notably, the soluble gas in lignite is never dominant in the gas composition. Therefore, gas in xylite lignite is mainly adsorbed. Due to carbonization, the fusain-rich lignite retains many unexpanded primary plant tissue structures and has developed macropore spaces and weak hydrophilicity. Therefore, the fusain-rich lignite has high free fluid porosity and the highest free gas storage potential. When the burial depth of the matrix lignite is less than 500 m, the methane is mainly adsorbed. The storage potential of free gas gradually exceeds that of adsorbed gas as the burial depth increases. There are apparent differences in the occurrence states and accumulation patterns of methane in different lithotypes of lignite. Clarifying methane’s occurrence and storage potential in different lithotypes of lignite are significant for evaluating methane resources and exploring the methane enrichment model. | Storage Potential of Multi-State Fluids in Different Lithotypes of Lignite: An In Situ Water-Gas-Bearing Analysis Based on Nuclear Magnetic Resonance | 10.1007/s11053-023-10172-w |
2023-06-01 | To cope with the problem of global warming caused by greenhouse gases, an environmentally friendly working fluid with low global warming potential (GWP) value was proposed to replace R507A which has a higher GWP value. This paper evaluated the thermodynamic properties and cycle performance of the alternative named RTB1. Firstly, the thermodynamic properties of RTB1 were investigated experimentally, including saturated vapor pressure and miscibility with polyol ester (POE) lubricating oil. The results showed that the saturated vapor pressure of RTB1 is 7.14% higher than that of R507A on average, and RTB1 has good miscibility with POE 32. Secondly, the flammability of RTB1 was tested by the flammability limits test system, and the experimental results showed that RTB1 was a non-flammable working fluid. Finally, the cycle performance of RTB1 and R507A under different operating conditions was compared. RTB1 is better than R507A in terms of cooling capacity per unit volume and coefficient of performance, however, the discharge temperature of RTB1 is higher than that of R507A. This work is of great significance to promote the elimination process of high-GWP working fluids and reduce emissions of greenhouse gases. | Thermodynamic analysis of a lower-GWP and nonflammable alternative to R507A | 10.1007/s10973-023-12121-4 |
2023-06-01 | Abstract The properties and mechanisms of fracture of hybrid composite materials (HCMs) based on flexible and brittle matrices reinforced with hybrid fibers of carbon, aramid, and ultrahigh molecular weight polyethylene (UHMWPE) are studied by the method of impact break (IB) under low speed impact. The composition of the hybrid fiber and the plasticity of the matrix have an effect on the properties and fracture mode of the HCM. It is established that the combination of carbon and aramid fibers in a hybrid fiber for reinforcing a flexible matrix (FM) makes it possible to create a material with delayed failure. It is shown that the impact fracture of the HCM with a flexible matrix requires a load twice as large as the load required for specimens with a brittle matrix. Hybrid composite materials in which there is a joint deformation of the matrix and the reinforcing fiber at all stages of loading up to failure have the highest strength. The mechanism of deformation and destruction of anisotropic HCMs upon impact is associated with the stepwise behavior. | Effect of the Hybridization of Carbon Fibers with Aramid and UHMWPE Fibers on the Impact Properties of Hybrid Carbon Fiber Reinforced Plastics | 10.1134/S2075113323030218 |
2023-06-01 | The two interfaces in direct contact with the channel are the main factors affecting the performance of MoS 2 FETs. They are the source–drain electrode contacts and the interface between the channel and the gate dielectric material. As carriers move through the channel, they may fluctuate if they encounter a non-uniform electrostatic field. Carrier fluctuations are a major cause of performance degradation in semiconductor devices and circuits, resulting from delayed turn-on in the channel and low carrier mobility. This issue is becoming increasingly pronounced as low-dimensional semiconductor materials are used or as devices are miniaturized to an extreme extent. In this study, we utilized low-temperature deposited indium electrodes and hexagonal boron nitride( h -BN) as gate dielectric materials in MoS 2 devices, aiming to minimize interfacial defects. The In-MoS 2 / h -BN device exhibited negligible contact resistance and interfacial Coulomb scattering, and a remarkably reduced density of dielectric traps, resulting in a negative threshold voltage shift of approximately 60 V and a tenfold improvement in carrier mobility. DC and low frequency noise (LFN) measurements were used to evaluate the impact of interfacial properties of the devices. The LFN modeling demonstrated that interfacial Coulomb scattering was reduced in the low-current region for devices utilizing the indium electrodes. The LFN provided reasonable results compared with the DC analysis, and also detailed information about the behavior of carriers. | Optimization of two major interfaces in MoS2 FETs with low frequency noise analysis | 10.1007/s40042-023-00825-7 |
2023-06-01 | In the metal additive manufacturing (AM) process of laser powder bed fusion (LPBF), there are a limited number of materials suitable for producing parts with high density and desired mechanical properties. To establish novel materials, it is essential to determine optimized process parameters in order to overcome process-related challenges and mitigate defects such as lack of fusion, keyholing, and balling. Scaling laws based on thermophysical properties and process parameters can be used to transfer knowledge from other materials or LPBF systems. In this work, a scaling law is used to adjust process parameters for single-track experiments over a wide range, which are laser power P L (100–1000 W), scan speed v s (300–2500 mm/s), and laser spot size d s (0.08–0.25 mm). Compared to existing studies, the parameter range is thus extended towards large laser spot sizes and high laser powers. The scaling law used is based on the calculation of the normalized enthalpy $$\frac{\Delta H}{{h}_{s}}$$ Δ H h s . The ratio of the deposited energy density $$\Delta$$ Δ H and the melting enthalpy h s correlates with the dimensions of the melt pool. According to the aspect ratio $${\delta }_{\mathrm{c}}$$ δ c of the melt pool of each single track, the respective melting mode—conduction, transition, and keyhole mode—was identified. The process parameters of the single tracks in transition mode were used to optimize the density of the LPBF specimens with varying hatch distance h d (0.06–0.12 mm), resulting in specimens with a relative density of > 99.8%. The proposed methodology can accelerate the process parameter finding for new alloys and avoid process-related defects. Graphical Abstract | Systematic approach to process parameter optimization for laser powder bed fusion of low-alloy steel based on melting modes | 10.1007/s00170-023-11377-2 |
2023-06-01 | Here we examine the water stable-isotope data from the Roosevelt Island Climate Evolution (RICE) ice core. Roosevelt Island is an independent ice rise located at the northeastern margin of the Ross Ice Shelf. In this study, we use empirical orthogonal function (EOF) analysis to investigate the relationship between RICE ice-core oxygen-18 isotopes (δ 18 O) and Southern Hemisphere atmospheric circulation during the extended austral winter (April–November). The RICE δ 18 O record is correlated with Southern Annular Mode (SAM) and Pacific–South American pattern 1 (PSA1), which both project onto the Amundsen–Bellingshausen Sea (ABS) geopotential height field. Pacific sector Southern Ocean, eastern Ross Sea, and West Antarctic’s atmospheric circulation, sea ice, and surface air temperature (SAT) anomalies, as well as RICE δ 18 O, are strongest when El Niño–Southern Oscillation (ENSO) and SAM are “in-phase”. That is when the SAM − /PSA1 + (El Niño) and SAM + /PSA1 − (La Niña) phasing prevails. When in-phase, the δ 18 O correlation with the 500-hPa geopotential height (Z500) is strong in regions (e.g., the Amundsen Sea) where their anomalies associated with SAM and PSA1 show the same sign. SAM − /PSA1 + (El Niño) and SAM + /PSA1 − (La Niña) is associated with positive and negative δ 18 O anomalies, respectively. RICE δ 18 O can aid in establishing past natural variability of the strength of the SH high-latitude Pacific sector ENSO-SAM connection and associated atmospheric circulation, sea ice, and SAT extremes. | The role of large-scale drivers in the Amundsen Sea Low variability and associated changes in water isotopes from the Roosevelt Island ice core, Antarctica | 10.1007/s00382-022-06568-8 |
2023-06-01 | In recent years, high refractive index polythiourethane materials have attracted increasing attention. In this study, the soft segment part of conventional polyurethane was replaced by ethylenedithiol, and a series of nanocomposite films containing Mercaptoethanol (ME) capped ZnS NPs were prepared by UV curing after the synthesis of the bifunctional linear prepolymer with hydroxyethyl acrylate as capping agent and trifunctional prepolymer with trimethylolpropane triacrylate as sulfhydrylate capping. ZnS NPs were well dispersed in the resin system, and the transmittance of the film decreased with the increase of ZnS content, but it did not float much and still has 80% transmittance at 40%. The addition of ZnS had a significant improvement on the refractive index. The RI of the system without the addition of particles was less than 1.5, the system with 40% was greater than 1.6. It was worth noting that the Abbe number was almost greater than 30, which was in the category of low dispersion. Graphical abstract Preparation of highly refractive polythiourethane-ZnS composite film by “click” chemical reaction | Polythiourethane composite film with high transparency, high refractive index and low dispersion containing ZnS nanoparticle via thiol-ene click chemistry | 10.1007/s13233-023-00144-7 |
2023-06-01 | Key technical innovations in the construction of Baihetan Hydropower Station Project | 10.1007/s42524-023-0253-5 | |
2023-06-01 | SARS-CoV-2 contaminated items in the cold chain becomes a threat to public health, therefore the effective and safe sterilization method fit for the low temperature is needed. Ultraviolet is an effective sterilization method while its effect on SARS-CoV-2 under low-temperature environment is unclear. In this research, the sterilization effect of high-intensity ultraviolet-C (HIUVC) irradiation against SARS-CoV-2 and Staphylococcus aureus on different carriers at 4 °C and − 20 °C was investigated. The results showed that dose of 15.3 mJ/cm 2 achieved more than 3 log reduction of SARS-CoV-2 on gauze at 4 °C and − 20 °C. The vulnerability of coronavirus to HIUVC under − 20 °C was not significantly different than those under 4 °C. Four models including Weibull, biphasic, log-linear tail and log linear were used to fit the survival curves of SARS-CoV-2 and Staphylococcus aureus . The biphasic model fitted best with R 2 ranging from 0.9325 to 0.9878. Moreover, the HIUVC sterilization correlation between SARS-CoV-2 and Staphylococcus aureus was established. This paper provides data support for the employment of HIUVC under low-temperature environment. Also, it provides a method of using Staphylococcus aureus as a marker to evaluate the sterilization effect of cold chain sterilization equipment. Graphical Abstract | High-Intensity Ultraviolet-C Irradiation Efficiently Inactivates SARS-CoV-2 Under Typical Cold Chain Temperature | 10.1007/s12560-023-09552-5 |
2023-06-01 | The high applicability of Bacterial Cellulose (BC) is often challenging due to its high production costs, which ultimately prevents its widespread use. Therefore, the present study aimed to investigate BC production using alternative feedstock to replace high-cost synthetic carbon and nitrogen sources and to evaluate the physical and structural properties of the produced BC membranes. BC was produced through a microbial consortium from kombucha, and the formulated alternative media sustained promising BC production, especially the association of apple wastes (at 10% (W/V)) with tea mixture, with a yield similar to BC produced on Hestrin–Schramm (HS) control media. Moreover, the BC samples produced in this alternative media also exhibited comparable properties to BC from HS media, with similar water-holding capacity and retention ability, thermal stability, mechanical behavior, and a crystallinity index of 87.61% and 88.08%, respectively. Thus, our findings substantiated that expensive substrates, such as glucose, peptone, and yeast extract, could be successfully replaced by apple wastes, black and green tea, for BC production while maintaining its remarkable physical and structural properties. Furthermore, besides the low-cost advantage, the bioconversion of apple waste also reduces the environmental burden caused by its disposal in landfills. | Sustainable bacterial cellulose production by low cost feedstock: evaluation of apple and tea by-products as alternative sources of nutrients | 10.1007/s10570-023-05238-0 |
2023-06-01 | Bauxite is widely used to produce alumina. There are many bauxite resources with high iron content. These resources could not be processed and utilized efficiently due to the high concentration of iron (Fe). The alkaline leaching process has been proposed to remove iron from these bauxite resources. Therefore, in this study, the alkaline leaching process was employed, and the effects of sodium dithionite (on the decomposition of iron oxides), sodium carbonate (adjustment of the solution pH), and oxalic acid (on the prevention of precipitation of Fe 2+ complexes and the decomposition of kaolinite) were investigated using a central composite design. The results showed that 77 and 54% of iron and silica were removed under optimum operating conditions. These conditions included the use of oxalic acid at a dosage of 24 g and sodium dithionite at a concentration of 0.08 M, reaction time of 75 min, solid content of 10%, pH of 8–8.2, and stirring speed of 700 rpm. The kinetics modeling indicated that the alkaline leaching of iron from high-iron bauxite was controlled by the product layer diffusion mechanism. In addition, the calculated activation energy was 18.8 kJ/mol. The removal mechanism was studied by X-ray diffraction, X-ray fluorescence, and Fourier transform infrared spectroscopy analysis. Graphical Abstract FTIR spectra of the leaching residue before and after washing. | Simultaneous Application of Oxalic Acid and Sodium Dithionite for Synchronous Removal of Iron and Silica from Low-Grade Bauxite: Kinetics and Mechanism | 10.1007/s40831-023-00661-w |
2023-06-01 | Industrial effluent is not always safe to the environment because of the presence of huge amounts of substantial heavy metals like arsenic, cadmium, chromium, nickel, mercury, etc. If the wastewater is disposed of in the environment without any prior treatment, it will result in environmental pollution that would affect water bodies, soil strata, and all other natural resources. This research focuses on the removal process of identified toxic heavy metals, i.e., mercury from effluent, using natural adsorbents like Ground Gulmohar seeds and Waste Tea powder. The performance of these adsorbents was compared with the removal efficiency of conventionally used material, i.e. Powdered Activated Carbon. Experimental parameters such as pH, contact time, adsorbent dosage, and initial concentration were taken into consideration to calculate the removal efficiency, and the accuracy of the results was interpreted with adsorption isotherm models. The findings of this research demonstrate that the natural adsorbents Waste Tea powder & Ground Gulmohar seeds have high efficiency in the removal of mercury metal concentration from prepared aqueous solution. | Effective removal of heavy metal: mercury concentration using natural adsorbents | 10.1007/s10668-023-03123-1 |
2023-06-01 | Abstract Upgraded plasma source based on atmospheric pressure glow discharge device and features of its operation are presented. The main purpose of the upgraded device is the generation of metal-contained plasma flows. A brief review of the state-of-the-art methods for generating metal-containing plasma at atmospheric pressure is given. The possibilities of the application of the described discharge system in research on the production of ultrafine powders and functional coatings are indicated. | Metal-Containing Plasma Source Based on Atmospheric Pressure Glow Discharge | 10.1134/S1063780X23600238 |
2023-06-01 | Abstract This paper presents an overview of epoxy compounds used to obtain low-combustible and fire-safe polymer composite materials. | Epoxy Binders for the Creation of Low-Combustible and Fire-Safe Types of Polymer-Composite Materials | 10.1134/S1995421223020119 |
2023-06-01 | Agriculture is one of the exposed sectors to abiotic stress conditions. There are diverse abiotic stress in which low temperature is an important abiotic stress limiting plant growth and development. The low temperature (0–20 °C) adaptive microbial communities are of particular interest because of their adaptability to prevailing conditions. Phosphorus is an important growth nutrient for the plants. Low temperature and phosphorus limitations act as the stress factors for the plants. Psychrotrophic microbiomes with P-solubilizing ability are gaining attention because of their amazing role in enhancing the availability of P and growth under low temperatures. In the present study, different crops with their rhizospheric soil from Poonch region of Jammu and Kashmir were collected for isolation of potential plant growth promoting psychrotrophic bacteria. A total of 65 isolates were obtained on different growth media. Among 65 isolates, 29 exhibited P-solubilizing capability. On basis of P-solubilizing ability and multiple PGP attributes, bacterial strain EU-PW75 was identified on basis of 16S rRNA gene sequencing as Serratia nematodiphila . The strain EU-PW75 was used for plant growth promotion of barley under conditions of low temperature where it efficiently improved the growth and physiological parameters of barley. The low temperature adaptive microbes with PGP activities could be useful for cold stress alleviation and plant growth promotion of crops growing under the low temperature. | Mitigation of low temperature stress and plant growth promotion in barley (Hordeum vulgare L.) by inoculation of psychrotrophic P-solubilizing Serratia nematodiphila EU-PW75 | 10.1007/s42976-022-00324-8 |
2023-06-01 | Two-dimensional (2D) hybrid metal halide perovskite is receiving more interest today due to being more stable and having a higher surface area-to-volume ratio than 3-dimensional (3D) hybrid metal halide perovskites. To create a 2D structure with high-efficiency properties, the A cation in the parental 3D structure should be replaced with a bulky organic cation (BOC). So in this study, we aim to investigate the structural, electrical, and optical characteristics of 2D (2-AMP)PbI 4 via CASTEP computer code and density functional theory (DFT). The computations utilize the local density approximation (LDA) and the generalized gradient approximation (GGA) techniques. The structural characteristics of GGA-PBEsol demonstrate great agreement with experiment data. The (2-AMP)PbI 4 structure consists of corner-sharing PbI 6 4− octahedra separated by alternating sheets of the double-protonated 2-AMP cation. Due to the spin–orbit coupling (SOC) effect, the electronic band gap was reduced from 1.92 to 0.98 eV. According to the partial density of states (PDOS), the Pb-p and I-p bonds supply the most electrons to the band gap. When it comes to optical characteristics, the actual part of the dielectric function reveals that this compound exhibits plasmonic behavior, which increases its capacity to absorb light. The absorption coefficient of (2-AMP)PbI 4 shows that this 2D compound able to absorb light in the range of UV and visible light, making it a possible candidate for high-efficiency solar cell devices. | Structural, electronic, and optical properties of lower-dimensional hybrid perovskite lead-iodide frameworks + SOC via density functional theory | 10.1007/s42247-023-00484-1 |
2023-06-01 | Low-temperature silicon nitride (SiN x ) films deposited by plasma-enhanced chemical vapor deposition (PECVD) have huge application potential in the flexible display. However, the applicability of SiN x largely depends on the film’s general properties, including flexibility, deposition rate, residual stress, elastic modulus, fracture strain, dielectric constant, refraction index, etc. Process optimization towards specific application by conventional experiment design needs lots of work due to the interaction of muti quality and process parameters. Therefore, an efficient global optimization approach for the process technology was proposed based on the Taguchi orthogonal experiment method considering muti-factor muti-responses. First of all, the Taguchi orthogonal experiment design and analysis was used to rank the influences of main process parameters on the quality characteristics, including radio frequency (RF) power, pressure, silane flow rate, ammonia flow rate and nitrogen flow rate. Then, the global optimization approach was carried out utilizing the multi-response optimizer considering the combination target of film formation rate, residual stress, dielectric constant, elastic modulus, fracture strain, refractive index. Finally, the optimal solution of the SiN x film was finally obtained and verified. | Global optimization of process parameters for low-temperature SiNx based on orthogonal experiments | 10.1007/s40436-022-00423-z |
2023-06-01 | Abstract Comparative data about the combustibility of adhesives of different chemical compositions are presented. The application of epoxy oligomers with chlorine or bromine atoms is considered for producing materials with enhanced fire-safety properties. The potential of adding phosphazenes with epoxy groups to adhesives with enhanced fire-safety properties is shown, as well as combinations of various types of materials for reducing polymer combustibility. | Adhesive-Material Combustibility-Reduction Methods. Part 2. Combustibility Reduction by Adding Low-Combustibility Oligomers | 10.1134/S1995421223020338 |
2023-06-01 | Adhesively bonded repaired aircraft composite structures are also susceptible to low-velocity impact (LVI) events. However, the impact responses and the residual behaviors of the bonded repaired structures are still not expressly revealed. In this paper, the impact damage resistance and residual compression behaviors of scarf repaired composite plates were investigated through experiments. LVI and compression after impact (CAI) experiments were carried out for both scarf repaired plates and virgin composite plates. Impact responses including the impact curves, dent depth, dissipated energy and delamination damage, and residual compression behaviors including the residual strength, failure mode and the failure process were compared and analyzed. The results show that scarf repaired plates get smaller dent depth but larger delamination area than the virgin plates due to the higher out-of-plane stiffness and the cushioning effect of the ductile adhesive layer. The large-area delamination causes a reduction of the compression strength due to sub-laminate buckling and delamination propagation. Therefore, scarf repaired plates might have lower residual compressive strength than virgin composite plates under the same impact energy. It is suggested to comprehensively adopt parameters such as delamination area and dent depth to characterize the impact damage resistance of the bonded scarf repaired structures. | Experimental Study on Impact Damage Resistance and Residual Compression Behaviors of Scarf Repaired Composite Plates | 10.1007/s10443-023-10118-8 |
2023-06-01 | Abstract Combustibility requirements for aircraft materials are shown. Data are presented about the main methods of making adhesives less combustible by adding fire retardants, such as halogenous and phosphoric compounds, as well as mineral fillers that release carbon dioxide and water vapor upon heating. Properties and purposes of low-combustibility adhesives, as well as adhesive-combustibility testing methods, are presented. | Adhesive-Material Combustibility-Reduction Methods. Part 1 | 10.1134/S1995421223020326 |
2023-06-01 | Near-surface projected wind changes in the Caribbean Sea (CAR) related to climate warming are analyzed using 24 General Circulation Models (GCM) from the CMIP6 intercomparison project. A multi-model ensemble mean is constructed to evaluate wind changes in CAR and the Caribbean Low Level Jet (CLLJ), using three different Socio Economic Pathways (SSPs) in the twenty-first century, and including their seasonal behavior. Models are validated against scatterometer data and a reanalysis product to assess their performance in the region. Best results are obtained from the MMM ensemble. Surface wind speed show significant spatially averaged trends in the 1850–2014 period. Larger trends are expected in the 2015–2100 period. Spatial changes in projected wind direction are not expected. Conversely, wind intensification has different spatial patterns in the dry and wet seasons when compared to the annual mean. In the wet season and SSP5-8.5 scenario, wind speed is expected to increase > 10% toward the south of the Colombian basin between 1990–2014 and 2076–2100 periods. Wind intensification will be greater between May and October. In all cases, projected wind intensification show a direct relation to the radiative scenario and is larger in the CLLJ when compared to CAR mean. Climate-related wind changes in CAR have the potential to affect regional climate, ocean dynamics and coastal communities. | Projected wind changes in the Caribbean Sea based on CMIP6 models | 10.1007/s00382-022-06535-3 |
2023-06-01 | Coherent elastic neutrino-nucleus scattering (CE $$\nu $$ ν NS), detected for the first time more than 40 years after its prediction, represents an experimental challenge because of its signature: a single nuclear recoil with energy in the range of 10 eV to a few 10’s keV on average. One of the main features of CE $$\nu $$ ν NS is its cross section, around two orders of magnitude higher compared with the inverse $$\beta $$ β decay. BASKET (Bolometers At Sub keV Energy Threshold) project aims at investigating cryogenic calorimeters for the CE $$\nu $$ ν NS detection, able to maintain the background level below the expected signature while being operated in above ground conditions in close vicinity to a nuclear reactor. The main requirements for such detectors are a low enough energy threshold of O(10 eV), and a fast signal rise time in the range of 0.1–1 ms to achieve good timing resolution and hence good mitigation of pile-up events. In this article, we report on the first tests of a prototype detector coupling a Li $$_2$$ 2 WO $$_4$$ 4 crystal to a magnetic metallic calorimeter (MMC) thermal sensor. | First Tests of Li
$$_2$$
2
WO
$$_4$$
4
Bolometric Detectors Using MMC Sensors for the Detection of CE
$$\nu $$
ν
NS | 10.1007/s10909-022-02911-9 |
2023-06-01 | Cryogenic detector and qubit readout systems often include radio-frequency low-pass filters (LPFs) at the input/output paths to protect the sensitive devices from stray radiation traveling down the coaxial lines. For this application, a popular solution is to use custom-made copper powder filters, which are LPFs with injection of copper powder-loaded epoxy. They are very effective in attenuating high frequency (THz and far infrared) radiation but often introduce a few dBs of undesired insertion loss at the readout band below 10 GHz. Here, we describe a LPF design concept based on low- $$T_{c}$$ T c ( $$\approx 700$$ ≈ 700 mK) Ti/TiN superconducting artificial (lumped-element-loaded) transmission lines. We carefully design the unit inductance $$L_{u}$$ L u and unit capacitance $$C_{u}$$ C u to make the cut-off frequency $$f_{c} = 1/(\pi \sqrt{L_{u} C_{u}}) \approx 30$$ f c = 1 / ( π L u C u ) ≈ 30 GHz and the characteristic impedance $$Z_{0} = \sqrt{L_{u}/C_{u}} \approx 50$$ Z 0 = L u / C u ≈ 50 Ohm. Above the gap frequency ( $$\approx 50$$ ≈ 50 GHz), the transmission line behaves as a lossy line made of normal metal which naturally attenuates the high-frequency radiations. In addition, the cavity resonances and spurious pass-bands at high frequencies can be effectively suppressed by adding a layer of microwave absorber below the substrate and by introducing an aperiodic loading of unit structures. A detailed design and electromagnetic simulation using realistic material parameters are presented. Our LPF design offers the advantages of close-to-zero insertion loss below 10 GHz, precise and sharp frequency roll-off, and linear phase response. The LPF can be placed in a separate package with compact size and easily connected to other superconducting circuits. | A Superconducting RF Low-Pass Filter Based on Ti/TiN Artificial Transmission Line for Detector and Qubit Readout | 10.1007/s10909-022-02918-2 |
2023-06-01 | Composite sandwich panels are known to possess high specific mechanical strength and impact resistance. The low-velocity impact test is performed to assess the impact resistance, damage tolerance, and strength of panels. Generally, it is difficult to calculate the damaged area induced by the impact test on the panels by visual inspection method on account of their colour visibility and irregular shapes. In this study, a novel method based on the digital image analysis technique combined with MATLAB programming is proposed to calculate the exact damage areas and can check its severity economically, and without any robust instrumentation. The results are compared with that of the visual inspection technique and confirmed that the proposed method was an effective tool for the evaluation of exact impact damage areas. | Evaluation of Damage Area on Low-Velocity Impact Tested AA3003 Sandwich Panels Using Digital Image Analysis: A Novel Method | 10.1007/s40033-022-00382-6 |
2023-06-01 | Alkyl polycyclic aromatic hydrocarbons (APAHs) are more toxic and persistent than their parent compounds. In this study, the concentrations of polycyclic aromatic compounds (PACs) in dust, topsoil and coal gangue from Huaibei Coal mine, China were analyzed by gas chromatography-mass spectrometry, confirming APAHs were the dominant pollutants. The mean concentrations of APAHs were substantially higher than those of 16 PAHs in both dust and topsoil. The mean concentration of APAHs in dust was 9197 µg kg −1 , accounting for 80% of the total mean concentration of PACs. The mean concentration of APAHs in topsoil was 2835 µg kg −1 , accounting for 77% of the mean concentration of PACs. Alkyl naphthalenes and alkyl phenanthrenes were the primary pollutants in APAHs. Their mean concentrations in dust and topsoil were 7782 µg kg −1 and 2333 µg kg −1 , respectively. This accounted for 85% and 82% of the concentration of APAHs, respectively. Additionally, low-molecular-weight APAHs dominated the PACs of the coal mine, exhibiting petrogenic characteristics; distribution of C1-C4 NAP and C1-C4 PHE exhibited “bell shape” pattern indicated as petrogenic source. Source identification indicated that the PACs were mainly derived from petrogenic sources and vehicle emissions, followed by biomass and coal burning. Fingerprinting information of dust and topsoil were consistent with coal gangue, indicating that PACs are most likely derived from coal gangue. Coalfields comparable to our study area are widely distributed in China. Therefore, investigating PAC pollution derived from coal gangue warrants further attention. | Contamination characteristics of alkyl polycyclic aromatic hydrocarbons in dust and topsoil collected from Huaibei Coalfield, China | 10.1007/s10653-022-01365-y |
2023-06-01 | Millimeter-sized objects like engine components, sand particles, or debris impact on the gas turbine blades very frequently during operation of a gas turbine. This is one of the major concerns in the aviation industry, and various studies and research have been done throughout the decades in preventing the damage. Such impacts may not affect or damage the gas turbine blades but the frequent impact leads to the fatigue of the gas turbine blades and eventually to failure. The low-velocity impact analysis of gas turbine rotor blades in aviation has been presented in this study. Impact analysis of spherical steel balls as impactors of different masses on titanium-alloyed rotor blades is recorded and the result data are collected. To verify the present method, the numerical data are also compared to open literature. The analysis has been done using ANSYS software considering factors like meshing sizes, impactor size, and velocity. | Low-Velocity Impact Damage Due to Debris Particles Impacted on Titanium Alloy (Ti–6Al–4V) Gas Turbine Blades | 10.1007/s40033-022-00372-8 |
2023-06-01 | Global warming is partly caused by massive emissions of carbon dioxide (CO 2 ), a greenhouse gas, in the atmosphere by industrial and other human activities. Consequently, there is a need for advanced methods to store and transform CO 2 into value-added chemicals, materials, and fuels. In particular, the electrochemical reduction of CO 2 into fuels and chemicals using renewable electricity appears as a long-term solution for the circular economy, yet this method is actually limited by low selectivity, activity, and stability of carbon–carbon coupling in aqueous electrolytes. Here we review the electrochemical reduction of CO 2 with emphasis on principles, electrocatalysts and production of compounds with either one carbon (C 1 ) or two or more carbons (C 2+ ). We discuss the application of bimetallic, oxide-derived, and crystal facet compounds, and their defect engineering and structure tuning. | Electrochemical reduction of carbon dioxide into valuable chemicals: a review | 10.1007/s10311-023-01565-7 |
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