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2020-10-01 | Abstract The synthesis was performed of grafted copolymers of acrylic acid on low molecular weight polyethylene in the presence of benzoyl peroxide in o -xylene solution. The formation of copolymers was proved by the methods of functional analysis of carboxyl groups and FTIR spectroscopy. The patterns of synthesis are shown, which made it possible to obtain graft copolymers in a wide range of compositions. X-ray diffraction analysis demonstrated that the presence of acrylic acid units in the copolymer leads to a decrease in the crystallinity of the copolymers compared to the initial low molecular weight polyethylene. | Synthesis and Structure of Grafted Copolymers of Acrylic Acid and Low Molecular Weight Polyethylene | 10.1134/S1070427220100031 |
2020-10-01 | Numerous studies have been carried out to ascertain the mechanisms of low-salinity and smart water flooding technique for improved oil recovery. Focus was often on brine composition and, specifically, the cationic content in sandstone reservoirs. Given the importance of the salt composition and concentration, tweaking the active ions which are responsible for the fluids–rock equilibrium will bring into effect numerous mechanisms of displacement which have been extensively debated. This experimental study, however, was carried out to evaluate the extent of the roles of chloride- and sulphate-based brines in improved oil recovery. To carry this out, 70,000 ppm sulphates- and chloride-based brines were prepared to simulate formation water and 5000 ppm brines of the same species as low-salinity displacement fluids. Core flooding process was used to simulate the displacement of oil by using four (4) native sandstones core samples, obtained from Burgan oil field in Kuwait, at operating conditions of 1500 psig and 50 °C. The core samples were injected with 70,000 ppm chloride and sulphates and subsequently flooded with the 5000 ppm counterparts in a forced imbibition process. Separate evaluations of chloride- and sulphate-based brines were carried out to investigate the displacement efficiencies of each brine species. The results showed that in both high- and low-salinity displacement tests, the SO 4 brine presented better recovery of up to 89% of the initial oil saturation (Soi). Several mechanisms of displacement were observed to be responsible for improved recovery during SO 4 brine displacement. IFT measurement experiments also confirmed that there was reduction in IFT at test conditions between SO 4 brine and oil and visual inspection of the effluent showed a degree emulsification of oil and brines. Changes in pH were observed in the low-salinity flooding, and negligible changes were noticed in the high-salinity floods. These results provide an insight into the roles of chloride and sulphate ions in the design of smart “designer” water and low-salinity injection scenarios. | An investigation into the roles of chlorides and sulphate salts on the performance of low-salinity injection in sandstone reservoirs: experimental approach | 10.1007/s13202-020-00972-8 |
2020-10-01 | The necessity to produce modern composites with an acceptable impact resistance is an essential task in automobile and aerospace industry that needs to be satisfied. This capability is addressed by noteworthy energy absorption augmentation which is the most vital characteristic of such composite materials. In this paper, nanofibers are applied as interleaves to modify the delamination strength with a minimum rise in weight and thickness of the high-modulus polypropylene/epoxy composites. Nylon 6,6 nanofibers are produced by the electrospinning method. The distribution of nanofibers across the mats is examined by SEM. Innegra fabrics have been applied in composite layers production. The proper hand lay-up manufacturing of the laminates has been assured by the assistance of a hydraulic press. The energy absorption capacity at the onset of breakdown and impact resistance of the nanomodified and non-modified laminates were determined by quasi-static three-point flexural for the former and low-velocity impact tests for the latter. The obtained results were compared. The results showed a 6.2 and 16.9% increase in the energy absorption capacity of nanomodified laminates in quasi-static three-point flexural test and low-velocity impact tests, respectively. In addition, low-velocity impact tests revealed 16 and 26% improvement in maximum load capacity. | Effect of interleaved composite nanofibrous mats on quasi-static and impact properties of composite plate | 10.1007/s13726-020-00845-1 |
2020-10-01 | This article examines the choices that might be needed for India’s energy sector under alternative mitigation scenarios. The article draws on the CD-LINKS study—a collaborative EU project under which seven pathways based on different combinations of carbon budget (high and low) and policy implementation (early and late) were developed and examined. This study uses the MARKAL energy system model to develop these scenarios. The three broad strategies that emerge for India include decarbonisation of electricity, electrification of end-uses and improvement in energy efficiency. We conclude that by undertaking early action, India can potentially prevent carbon lock-in and leapfrog to renewables from coal in the power sector. However, early action scenarios exhibit higher cost than their delayed action counterparts. Several other barriers and challenges also need to be addressed in order to enable large-scale uptake of low-carbon technologies. India may need to come up with innovative mechanisms to ensure a smooth and just transition for the economy. | India’s energy sector choices—options and implications of ambitious mitigation efforts | 10.1007/s10584-020-02885-1 |
2020-10-01 | Abstract Unoccupied electronic states in the energy range from 5 to 20 eV above the Fermi level have been studied in ultrathin films of dimethyl-substituted thiophene–phenylene cooligomers CH 3 -phenylene–thiophene–thiophene–phenylene–CH 3 (CH 3 –PTTP–CH 3 ) on polycrystalline gold surfaces of two types: the ex situ Au layer thermally deposited in a special chamber and the in situ Au surface prepared inside an analytical chamber. The film structure is studied by the X-ray diffraction (XRD) method. The formation of a superposition of the amorphous phase and the crystalline phase with period 3.8 nm is discussed. The energy positions of the maxima of the unoccupied electronic states and the character of formation of the boundary potential barrier have been studied by the total current spectroscopy (TCS). The structures of the FSTCS maxima of the 5–7-nm-thick CH 3 –PTTP–CH 3 films are not different when using various types of Au substrates and the ZnO semiconductor surface prepared by atomic layer deposition (ALD). As a CH 3 –PTTP–CH 3 layer is deposited on the ex situ Au and in situ Au surfaces, the electron work function increases insignificantly (by ~0.1 eV) as the coating thickness increases to 5–7 nm. At such thicknesses of the CH 3 –PTTP–CH 3 films, the electron work function is 4.7 ± 0.1 eV in the case of the ex situ Au substrate and 4.9 ± 0.1 eV in the case of the in situ Au substrate. A possible influence of the processes of physicochemical interaction at the boundary between the film and the substrate on the formation of the boundary potential barrier in the structures under study is discussed. | Unoccupied Electron States of Ultrathin Films of Thiophene–Phenylene Cooligomers on the Surface of Polycrystalline Gold | 10.1134/S1063783420100170 |
2020-10-01 | The performance of FASTlab synthesizers and three-year operational experience at four hospitals in Taiwan were analyzed and summarized. [ 18 F]FDG was daily produced with about 80% (EOB) of RCY and USP-compliant specification at four centers in Taiwan. The easiness to operate the cassette and high RCY of produced [ 18 F]FDG are the main advantages for clinical use at the PET center of hospitals, but some underlying defects of the synthesizer or cassettes should be paid attention to and proactively scrutinized, such as cassette leakage and low tC18 trapping yield. | Performance analysis and operational experience of [18F]FDG production with cassette-type modules in four hospitals of Taiwan | 10.1007/s10967-020-07348-6 |
2020-10-01 | The abnormal noises, such as clunking and popping, are usually generated when the car turns or drives over bumps. It could happen frequently when the free gap (clearance) values in the axial direction of the lower control arm ball joint are higher than normal values. The spherical surface of the ball stud is commonly assumed to have been corroded by foreign substances such as water, and the rough surface of the corroded ball stud accelerates the abrasion of the bearing contact portion to increase the free gap. Thus, the dust cap material and shape have been improved over time. However, there are still recurrences. The objective of this study was to evaluate two ball studs with different plating thicknesses and one uncoated sample from the reproducibility test simulating vehicle behavior conditions under environment test conditions. The findings of this study were as follows: First, the ball stud plating is advantageous in corrosion resistance, however, the thickness of the plating is uneven and the surface becomes rough with time, thereby accelerating the abrasion of the bearing contact portion. Second, as the surface of the ball stud wears, oscillating torque decreases and the axial free gap increases, which is more disadvantageous as the thickness of the ball stud sphere becomes thicker. Therefore, uncoated ball joint was defined as the best option. | Practical Evaluation of Ball Stud Plating Effects on the Increase of Free Gap of Ball Joints in the Vehicle | 10.1007/s12239-020-0104-x |
2020-10-01 | Aims Magnesium (Mg) deficiency is detrimental to plant growth. However, how plants respond to Mg deficiency via regulation of Mg uptake and allocation is yet not fully understood. In this study, we tested whether Mg isotope compositions (δ 26 Mg) associated with Mg mass balance of the plants could be used as an indicator to trace Mg uptake and subsequent translocation processes under sufficient and low-Mg supply conditions. We aimed at using stable isotope fractionation as a novel proxy for nutrient uptake and cycling in plants. Methods We grew wheat plants ( Triticum aestivum ) in a greenhouse under control (1 mM Mg) and low-Mg supply (0.05 mM Mg) conditions, respectively. The Mg concentrations and isotope compositions in roots, stems, leaves and spikes/grains at different growth stages were analyzed. Results Wheat plants were systematically enriched in heavy Mg isotopes relative to the nutrient solution regardless of Mg supply conditions. With crop growth, the δ 26 Mg of the whole plants, as well as each plant organ, gradually shifted towards higher values in the control. However, the δ 26 Mg value of the whole plants in the low-Mg supply did not vary significantly. In addition, the wheat stems and spikes showed continuous enrichment of lighter Mg isotopes in the low-Mg supply than those in the control. Conclusions As reflected from Mg isotope compositions, the Mg supply in the growth media could affect the Mg uptake and subsequent translocation processes in plants. Changes in δ 26 Mg indicated that wheat plants likely regulated their Mg uptake strategy by switching between active and passive pathways during their life cycle. When Mg supply was low, a more negative δ 26 Mg value of the spikes suggested a potentially enhanced remobilization of Mg from leaves to spikes. Our results showed that Mg stable isotopes can provide new insights into plants’ response to nutrient shortage. | Magnesium isotope fractionation reflects plant response to magnesium deficiency in magnesium uptake and allocation: a greenhouse study with wheat | 10.1007/s11104-020-04604-2 |
2020-10-01 | New N, N ′-bis(4,6-dimethylpyrimidin-2-yl)- and N, N ′-bis(2,3,5,6-tetrafluorophenyl)-substituted pyromellitic diimides were synthesized. Their properties were studied in comparison with the previously synthesized N, N ′-bis(4-fluorophenyl)pyromellitic diimide. Thermogravimetry, UV spectroscopy, cyclic voltammetry, and quantum chemical calculations in the framework of the density functional theory were used to characterize the synthesized compounds. The introduction of the pyrimidine cycle significantly decreases the energy of the lowest unoccupied molecular orbital. The highest occupied molecular orbitals in all compounds synthesized are deep-lying (about −7 eV). | Synthesis and study of N,N′-disubstituted derivatives of pyromellitic diimide | 10.1007/s11172-020-2983-4 |
2020-10-01 | Abstract Reading the memristor memory cell without changing its resistance state is one of the potential problems to be addressed in the memristor-based memory design. This paper presents a novel read scheme that achieves a non-destructive read operation, consumes less power, provides high endurance and adapts itself based on the process variations. The proposed scheme uses built-in self-tuning circuitry to obtain the optimum amplitude and width of the refresh pulse required to completely retrieve the state of the memristor after the read cycle. As the scheme uses refresh pulse only when needed, the scheme saves nearly 50% of average power when compared with a conventional fixed pulse read method. The self-tuning circuits are validated by a generic, accurate, and efficient “voltage threshold adaptive memristor” model. The validation results prove that the proposed tuning circuitry achieves optimum refresh pulse size under various read disturbance faults. Graphic abstract | Variation-tolerant, low-power, and high endurance read scheme for memristor memories | 10.1007/s10470-020-01702-0 |
2020-10-01 | Groundwater quality samples from 33 wells were collected in the lower Ketar watershed (Ethiopia) to study its suitability for domestic and irrigation purposes. Samples were evaluated for major ions and physicochemical properties. In 58% of the samples analyzed, Ca 2+ is the dominant cation and Na + dominates the remaining 42% of the samples. Among the anions found during analyzation, HCO 3 − is the solo dominant ion in all the wells sampled. The order of the concentration of the major ions was Ca 2+ > Na + > Mg 2+ > K + for the cations and HCO 3 − > SO 4 2− > Cl > NO 3 − for the anions. AquaChem analysis shows that Ca–HCO 3 and Na–HCO 3 are the major water types in the area. The analyses indicated that the dissolution of fluorite or fluorapatite is the possible source of the high fluoride concentration in the area. And, the interactions between water and rock and cation exchanges mainly determine the water quality. The suitability of the groundwater for use in irrigation was evaluated based on the salinity (EC), SAR, %Na, RSC, PI, KR, and the USSL Salinity diagram. The groundwater from most of the wells can be used for irrigation without any significant restriction except for a few of the wells downstream. Its suitability for domestic use was evaluated by comparing with the WHO standard limits. The parameters limiting the use of this groundwater for drinking purposes are F − (94%), HCO 3 − (45%), and Ca 2+ (33%). All the remaining major cations and anions complied with the WHO standard limits for drinking. | Groundwater quality evaluation for different uses in the lower Ketar Watershed, Ethiopia | 10.1007/s10653-019-00508-y |
2020-10-01 | Plastics composed of polyethylene are non-biodegradable and are mostly harmful to the environment. Literature studies documented that the extent of microbial degradation of low-density polyethylene (LDPE) seems to be insufficient and the underlying mechanisms of such degradation remain unexplored. In the present study, efforts were given to degrade LDPE by a recently isolated bacteria Enterobacter cloacae AKS7. Scanning electron microscopic (SEM) image, tensile strength, and weight loss analysis confirmed the efficient degradation of LDPE by AKS7. To investigate the mechanism, it was observed that with the progression of time, the extent of microbial colonization got increased considerably over the LDPE surface. It was also observed that the organism (AKS7) gradually increased the secretion of extracellular polymeric substances (EPS) suggesting the formation of efficient biofilm over the LDPE surface. Furthermore, to comprehend the role of cell-surface hydrophobicity towards biofilm formation, two mutants of AKS7 were screened that showed a considerable reduction in cell-surface hydrophobicity in contrast to its wild type. The result showed that the mutants revealed compromised LDPE degradation than wild-type cells of AKS7. Further investigation revealed that the mutant cells of AKS7 were incapable of adhering to LDPE in contrast to wild-type cells. Thus, the results demonstrated that the cell-surface hydrophobicity of AKS7 favors the development of microbial biofilm over LDPE that leads to the enhanced degradation of LDPE by AKS7. Therefore, the organism holds the assurance to be considered as a promising bio-remediating agent for the sustainable degradation of polythene-based hazardous waste. | Degradation of low-density poly ethylene (LDPE) by Enterobacter cloacae AKS7: a potential step towards sustainable environmental remediation | 10.1007/s00203-020-01926-8 |
2020-10-01 | Reducing nitrogen (N) input can improve crop productivity in cereal-legume intercrops, but the impact on phosphorus (P) acquisition is unclear. A 10-year (2009–2018) field experiment was conducted to quantify how P acquisition by sugarcane ( Saccharum officinarum ) was affected by intercropping with soybean ( Glycine max (L.) Merrill at 1:1 and 1:2) with two N inputs (300 kg ha −1 [reduced], 525 kg ha −1 [conventional]). Nitrogen was supplied only to the sugarcane crop, and soybean received no N. There was a significantly higher land-equivalent ratio of sugarcane-soybean intercropping than of the sole cropping, and the intercropping advantage was more pronounced under reduced N input which can be associated with high degree of complementary N use. Furthermore, soybean intercropping with reduced N input stimulated acid phosphomonoesterase activity and depleted organic P in the rhizosphere of sugarcane, resulting in increased sugarcane stem P concentration and system P-use efficiency. The interspecific facilitation of P acquisition could be associated with the increased symbiotic N 2 fixation in soybean, soil microbial biomass and activity under reduced N input. In conclusion, soybean intercropping with reduced N input to sugarcane enhanced rhizosphere enzymatic organic P transformation and sugarcane P acquisition, which may contribute to maintaining a sustainable sugarcane production under low N supply. The findings advance our understanding of interactions between N and P cycling and provide new evidence for the value of cereal-legume intercrops in reducing fertilizer input. | Soybean (Glycine max (L.) Merrill) intercropping with reduced nitrogen input influences rhizosphere phosphorus dynamics and phosphorus acquisition of sugarcane (Saccharum officinarum) | 10.1007/s00374-020-01484-7 |
2020-10-01 | The analyses of hydrocarbon reservoirs in the high-frequency reef and shoal facies of the Lower Ordovician carbonate successions in the Penglaiba Formation (O 1 P) and Yingshan Formation (O 1–2 Y) in the Tazhong (Katake) Uplift in central Tarim basin showed three types of hydrocarbon reservoirs: type 1 associated with synsedimentary facies, type 2 developed by hot active basinal dissolution fluids [mesogenetic fluids, geothermal/hydrothermal fluids and thermochemical sulfate reduction-related fluids] and tectonic activity, and type 3 are hypogenic–epigenetic karst reservoirs formed by meteoric and mesogenetic dissolution fluids. Porosity and permeability development in the reef and shoal facies in the highstand system tracts (HST) of the third-order sequence cycles (SQ1–SQ3) correlates well with regression peaks in O 1 P and O 1–2 Y, mostly related to multiphase tectonic activity, long-term exposure, denudation and dissolution in near-surface to shallow burial settings. The carbonate successions in the O 1 P and O 1–2 Y are composed of seventeen microfacies (MF-1 to MF-17) deposited on a shallow marine platform. Six main groups of microfacies associations (MFA-1 to MFA-6) were recognized, with each microfacies association corresponding to the transgressive system tracts and HST of SQ1–SQ4 in O 1 P and O 1–2 Y. The microfacies represent specific sedimentary environment including platform interior and platform margin deposited under particular hydrodynamic conditions. Tectonics and frequent relative sea-level fluctuation associated with rapid transgression and slow regression favored the deposition of the large-scale vertical stacking, high-frequency reef and shoal facies across the carbonate platforms in this uplift. The hydrocarbon reservoirs in this study have relatively moderate porosity and low permeability, and are somewhat potential reservoirs for hydrocarbon exploration in the Tazhong Uplift. | Hydrocarbon reservoir development in reef and shoal complexes of the Lower Ordovician carbonate successions in the Tazhong Uplift in central Tarim basin, NW China: constraints from microfacies characteristics and sequence stratigraphy | 10.1007/s13202-020-00936-y |
2020-10-01 | Abstract This paper presents recent data on the population of the anadromous vimba bream ( Vimba vimba vimba ), introduced in the Volga basin. After penetration to the downstream section of the Volga River from the Volgograd Reservoir, vimba bream can be found throughout the entire unregulated stretch downstream of the Volga Hydroelectric Station. Observations show that the population size changes naturally during the year owing to its spawning migration. At the same time, a gradual transformation of the seasonal dynamics of the species is observed. As populations spread further downstream, the migrations of spawners downstream of the dam become longer, and the population density decreases. Also a seasonal redistribution takes place, with reduced migration observed in autumn and increased migration during spring. Meanwhile, the growth rate in the downstream section of the Volga River is comparable to the growth rate of populations in the Volgograd and Tsimlyansk reservoirs. Spawning occurs on in-channel spawning grounds. Yearlings are observed over a distance of 100 km downstream of the dam. In addition to Vimba bream, single specimens of Caspian bream ( V. v. persa ) are also recorded. | The Distribution of Vimba Bream Vimba vimba
vimba (Actinopterygii: Cyprinidae) in the Unregulated Section of the Lower Volga River | 10.1134/S2075111720040025 |
2020-10-01 | Abstract It is for the first time that silver sulfide colloidal solutions were prepared by chemical deposition from silver nitrate and sodium sulfide solutions in heavy water D 2 O. Sodium citrate served as the stabilizer. The sizes of Ag 2 S nanoparticles in colloidal solutions were assessed by dynamic light scattering (DLS) measurements and electron microscopy. The silver sulfide nanoparticles in heavy water colloidal solutions prepared from batches having various reagent concentrations had sizes in the range from 3 to 19–20 nm. The increasing silver nitrate concentration and decreasing sodium citrate concentration in the batch only slightly increased the sizes of Ag 2 S nanoparticles in the prepared colloidal solutions. The silver sulfide colloidal solutions prepared with heavy water D 2 O retained their stability and unchanged nanoparticle sizes when stored for more than 100 days. | Synthesis of Silver Sulfide Colloidal Solutions in Heavy Water D2O | 10.1134/S0036023620100174 |
2020-10-01 | Advanced Internet-of-Things applications require control-oriented codes to be executed with low latency for fast responsivity while their advanced signal processing and decision making tasks require computational capabilities. For this context, we propose three multi-issue core designs featuring an exposed datapath architecture with high performance, while retaining energy-efficiency. These features are achieved with exploitation of instruction-level parallelism, fast branching and the use of an instruction register file. With benchmarks in control-flow and signal processing application domains we measured in the best case 64% reduced energy consumption compared to a state-of-the-art RISC core, while consuming less silicon area. A high-performance design point reaches nearly 2.6 GHz operating frequency in the best case, over 2× improvement, while simultaneously achieving a 14% improvement in system energy-delay product. | Energy Efficient Low Latency Multi-issue Cores for Intelligent Always-On IoT Applications | 10.1007/s11265-020-01578-3 |
2020-10-01 | Objective To observe the effect of scraping therapy (ST) on the immune balance of serum helper T (Th) 1/Th2 cells in autologous nucleus pulposus transplantation non-compressive lumbar disc herniation (LDH) model rats, and explore the immune mechanism of ST in reducing LDH pain. Methods Seventy-two male Sprague-Dawley (SD) rats were randomly divided into a model group, a sham operation group and a ST group, with 24 rats in each group. Autologous nucleus pulposus transplantation non-compressive LDH models were established in the model group and ST group, while the rats in the sham operation group underwent sham operation without model establishment. On the fifth day after the model was successfully prepared, rats in the ST group received ST, once every other day, 3 times as a course for a total of 3 courses. Six rats in each group were randomly selected to observe their pain thresholds, and peripheral blood of the rats was collected before the first scraping treatment and at the end of the first, second, and third courses of treatment. The serum was isolated and enzyme-linked immunosorbent assay (ELISA) was applied for the detection of rat serum interferon (IFN)-γ, interleukin (IL)-4 and IL-10. Results Compared with the model group, the pain threshold in LDH rats in the ST group increased ( P <0.05), the serum IFN-γ level was significantly reduced ( P <0.05), but the levels of IL-4 and IL-10 did not change significantly (both P >0.05). At the end of the second and third courses of treatment, the IFN-γ/IL-4 ratio was negatively correlated with the pain threshold in the rats, and the IFN-γ/IL-4 ratio was significantly reduced in the ST group ( P <0.01). Conclusion ST can help suppress the Th1 immunity in LDH rats triggered by the autologous nucleus pulposus, restore the immune balance of Th1/Th2, and reduce the pain of LDH. 目的 观察刮痧对自体髓核移植非压迫性腰椎间盘突出症(LDH)模型大鼠血清辅助T(Th)1/Th2细胞免疫平 衡的影响, 探究刮痧降低LDH疼痛的免疫作用机制. 方法 将72只雄性Sprague-Dawley (SD)大鼠随机分为模型组、 假手术组和刮痧组, 每组24只。模型组与刮痧组大鼠建立自体髓核移植非压迫性LDH模型, 假手术组只做假手术 处理。模型组与假手术组不予治疗, 刮痧组于造模后第5天开始干预治疗, 隔日刮1次, 3次为1个疗程, 共3个疗程。 分别于造模后、刮痧前、第1疗程结束时、第2疗程结束时和第3疗程结束时, 每组随机取6只大鼠, 观察其痛阈, 并收集大鼠外周血。采用酶联免疫吸附测定法(ELISA)检测大鼠血清干扰素(IFN)-γ、白介素(IL)-4和IL-10. 结果 与 模型组比较, 刮痧能升高LDH大鼠痛阈值( P <0.05), 显著降低血清IFN-γ水平( P <0.05), 对IL-4和IL-10水平无显著影 响(均 P >0.05)。第2、3疗程结束时, IFN-γ/IL-4比值水平与大鼠痛阈值呈负相关, 刮痧组IFN-γ/IL-4比值明显降低 ( P <0.01). 结论 刮痧能抑制自体髓核引起的LDH大鼠Th1免疫, 使机体Th1/Th2免疫失衡恢复到正常状态, 并减 轻其疼痛. | Effect of scraping therapy on Th1/Th2 balance in rats with lumbar disc herniation | 10.1007/s11726-020-1198-4 |
2020-10-01 | Low-carbon pilot (LCP) policy aims to not only achieve economic development but also address climate change problems in China. With a difference-in-difference (DID) approach, this study provides empirical evidence to support the policy’s implementation by analysing its impacts on green total factor productivity (GTFP). We find that the implementation of the low-carbon pilot policy has a significant positive impact on GTFP. The low-carbon pilot policy significantly improves the GTFP in the year following implementation, and its efficacy diminishes over time. In terms of mechanism analysis, the policy enables China to achieve win-win development through industry structure adjustment and foreign direct investment (FDI) inflows. Innovation does not immediately improve GTFP, although the low-carbon pilot policy promotes regional innovation. Our results provide strong support for China’s recent third set of low-carbon pilot policies. As for global mitigation strategy, countries should incorporate the low-carbon development path into their strategic planning. In particular, developing countries should enforce more efforts on low-carbon development as such development path may improve their green productivity. It helps narrow the gap between developing and developed countries. | Can a low-carbon development path achieve win-win development: evidence from China’s low-carbon pilot policy | 10.1007/s11027-019-09897-y |
2020-10-01 | Russia is one of the largest carbon emitters in the world, possessing huge resources of both fossil fuels and zero-carbon energy sources. The Paris Agreement targets require substantial efforts to limit global warming to “well below 2 °C”. Energy-economic modeling provides sound conclusions that continuation of existing energy and climate policy will lead to stabilization of energy carbon emissions in Russia at the current level in 2010–2050 (about 30% below 1990). Stronger mitigation policies could gradually reduce domestic energy CO2 emissions by 61% from 2010 to 2050 (75% below 1990). Deep decarbonization policies with even more ambitious commitments could ensure an 83% reduction in energy CO2 emissions from 2010 levels (88% below 1990) by 2050. All key sectors (energy, industries, transport, and buildings) can play a substantial role in decarbonizing the national economy. However Russia’s historical reliance on domestic consumption and exports of fossil fuels creates strong barriers to decarbonization. Emission reduction costs are expected to be below 29 USD/tCO2 by 2030, 55 USD/tCO2 by 2040, and 82 USD/tCO2 by 2050 in the most ambitious decarbonization scenario. The results of this study provide insights into how Russia can enhance its ambitions to implement the Paris Agreement and contribute to global efforts toward building a climate-neutral economy by 2050. | The low carbon development options for Russia | 10.1007/s10584-020-02780-9 |
2020-10-01 | The role of malondialdehyde-modified low-density lipoprotein (MDA-LDL), an oxidized LDL, in the pathophysiology of autism spectrum disorder (ASD) is unclear. We studied association between MDA-LDL and behavioral symptoms in 11 individuals with ASD and 7 age -matched normal controls. Behavioral symptoms were assessed using the Aberrant Behavior Checklists (ABC). Because small sample size in this study, three measures were conducted: first, employment of adaptive Lasso for enhancing the accuracy of prediction and interpretability; second, calculation of coefficient of variation for an appropriate selection of plasma variables; and third, selection of good candidates of plasma variables. Plasma levels of MDA-LDL, eicosapentaenoic acid, docosahexaenoic acid (DHA) and DHA/arachidonic acid ratios were significantly higher, while plasma superoxide dismutase (SOD) levels were significantly lower in the ASD group than in the control group. The total ABC scores were significantly higher in the ASD group than in the control group. Multiple linear regression analysis and the adaptive Lasso revealed association of increased plasma DHA levels with the ABC total scores and increased plasma MDA-LDL levels. Such association between DHA and plasma MDA-LDL levels may contribute to behavior in individuals with ASD. | The role of lipid peroxidation in individuals with autism spectrum disorders | 10.1007/s11011-020-00585-4 |
2020-10-01 | The aim of the present study was to investigate the influence of low-level laser radiation at a wavelength of 650 nm for treating post-herpetic neuralgia, an extremely painful condition which frequently occurs severely in old age and may persist for years with no predictable course. In total, fifteen patients were included in the present study, out of which 8 were females and 7 were males aged between 42 and 82 years. All patients were treated through 16 sessions for 8 weeks, and pain scoring was done on a visual analogue scale and statistical analysis was made for comparison before and after treatments. The final pain score was 0 in 11 patients although their initial pain score was severe in 8 and moderate in 3 patients. In three patients, pain reduced to mild intensity (2–3), and in one, the final pain score was 4 on the visual analogue scale. Patients treated during the present study have not complained for recurrence of pain or any other abnormality even after many months since completion of the therapy. Overall, low-level laser therapy (LLLT) proved itself an excellent therapeutic modality for the relief of pain in post-herpetic neuralgia patients, which may replace pain management medicines in future. | Role of low-level laser therapy in post-herpetic neuralgia: a pilot study | 10.1007/s10103-020-02969-5 |
2020-09-29 | Deep-sea sediment is extremely important in marine scientific research, such as that concerning marine geology and microbial communities. The research findings are closely related to the in-situ information of the sediment. One prerequisite for investigations of deep-sea sediment is providing sampling techniques capable of preventing distortion during recovery. As the fruit of such sampling techniques, samplers designed for obtaining sediment have become indispensable equipment, owing to their low cost, light weight, compactness, easy operation, and high adaptability to sea conditions. This paper introduces the research and application of typical deep-sea sediment samplers. Then, a representative sampler recently developed in China is analyzed. On this basis, a review and analysis is conducted regarding the key techniques of various deep-sea sediment samplers, including sealing, pressure and temperature retaining, low-disturbance sampling, and no-pressure drop transfer. Then, the shortcomings in the key techniques for deep-sea sediment sampling are identified. Finally, prospects for the future development of key techniques for deep-sea sediment sampling are proposed, from the perspectives of structural diversification, functional integration, intelligent operation, and high-fidelity samples. This paper summarizes the existing samplers in the context of the key techniques mentioned above, and can provide reference for the optimized design of samplers and development of key sampling techniques. | Review and Analysis of Key Techniques in Marine Sediment Sampling | 10.1186/s10033-020-00480-0 |
2020-09-29 | Hybrid acoustic-RF systems offer excellent ranging accuracy, yet they typically come at a power consumption that is too high to meet the energy constraints of mobile IoT nodes. We combine pulse compression and synchronized wake-ups to achieve a ranging solution that limits the active time of the nodes to 1 ms. Hence, an ultra low-power consumption of 9.015 µW for a single measurement is achieved. The operation time is estimated on 8.5 years on a CR2032 coin cell battery at a 1 Hz update rate, which is over 250 times larger than state-of-the-art RF-based positioning systems. Measurements based on a proof-of-concept hardware platform show median distance error values below 10 cm. Both simulations and measurements demonstrate that the accuracy is reduced at low signal-to-noise ratios and when reflections occur. We introduce three methods that enhance the distance measurements at a low extra processing power cost. Hence, we validate in realistic environments that the centimeter accuracy can be obtained within the energy budget of mobile devices and IoT nodes. The proposed hybrid signal ranging system can be extended to perform accurate, low-power indoor positioning. | High precision hybrid RF and ultrasonic chirp-based ranging for low-power IoT nodes | 10.1186/s13638-020-01795-1 |
2020-09-28 | Within the framework of the AdS/CMT correspondence asymptotically anti-de Sitter black holes in four space-time dimensions can be used to analyse transport properties in two space dimensions. A non-linear renormalisation group equation for the conductivity in two dimensions is derived in this model and, as an example of its application, both the Ohmic and Hall DC and AC conductivities are studied in the presence of a magnetic field, using a bulk dyonic solution of the Einstein-Maxwell equations in asymptotically AdS4 space-time. The Q $$ \mathcal{Q} $$ -factor of the cyclotron resonance is shown to decrease as the temperature is increased and increase as the charge density is increased in a fixed magnetic field. Likewise the dissipative Ohmic conductivity at resonance increases as the temperature is decreased and as the charge density is increased. The analysis also involves a discussion of the piezoelectric effect in the context of the AdS/CMT framework. | A renormalisation group equation for transport coefficients in (2 + 1)-dimensions derived from the AdS/CMT correspondence | 10.1007/JHEP09(2020)169 |
2020-09-26 | Coal is the most important primary energy in China. Although the proportion of coal in China's total energy consumption continues to decline it will still be the main energy in China for a long time in the future. As the largest contributor to China's greenhouse gas emissions, the energy conservation and emission reduction of coal industry will be the most critical step for China to cope with global climate change and solve environmental problems at present and in the future for a long time. The object of this study was coal mining in China. Life cycle assessment (LCA) was used to quantify carbon emissions in whole process of coal mining, including mining, ventilation, drainage, power consumption, transportation, and post-mining activities. The analysis result shows that the carbon emissions of producing tons of coal are 164.403 kg of carbon dioxide equivalent per ton. The analysis further emphasizes that the methane contributes the most, accounting for 62.21% of the total emissions, and plays an important role in the full life cycle of coal mining. Therefore, it presents a potential to mitigate the environmental impact of coal mining, and its main task is to recover and recycle methane. Based on the technical level, this study puts forward the low-carbon development countermeasures for coal enterprises. Then the technical system of methane emission control and utilization is constructed from three aspects: coal-bed methane development, gas extraction, and utilization and gas utilization. Finally, a trinity resource utilization system of coal mine gas is constructed. This study hopes to help practitioners to realize the importance of coal mine methane to the coal mining process. If the efficient resource utilization of methane be realized, it could not only save energy and reduce emissions in coal enterprises, but also promote the safety production of coal mines and improve the economic benefits of coal mines. It is also of great significance for optimizing China's energy structure, realizing low-carbon transformation, and safeguarding China's strategic energy security. | Carbon emission assessment and control measures for coal mining in China | 10.1007/s12665-020-09189-8 |
2020-09-22 | This study aims to assess the groundwater quality and the origin of water mineralization in an environment with high anthropogenic pressure in the municipality of Treichville. Twenty-one water samples were analysed to determine the quality. Kruskal–Wallis nonparametric test, Mann–Whitney test, Kohonen algorithm, and water table building were used to determine the factors influencing the mineralization. The results showed that the well’s water contains chemical and bacteriological elements whose concentrations are higher than the standards authorized by the World Health Organization (WHO). Thus, high levels of nitrate (peak = 173.1 mg L −1 ), phosphate (peak = 1.03 mg L −1 ), lead (peak = 2.987 mg L −1 ), and Escherichia coli (peak = 2.31 × 10 5 UFC 100 mL −1 ) were obtained in these waters. So, the groundwater is not suitable for human consumption. The most mineralized waters are found in the areas near the Ebrié Lagoon and extend in the direction including the low-income neighbourhoods of Biafra, Nanan Yamousso and Appolo. Pollutant transfer is continuous in the study area and comes from surface sewage, latrines, sewage disposal systems, well water collection materials, and the Ebrié Lagoon. Indeed, the pollutants leave Biafra neighbourhoods where water is heavily polluted and the pollution is amplified by the presence of septic tanks and latrines located on the line of groundwater flow. The main factors influencing water quality are the lagoon water intrusion, the advection mechanism linked to the infiltration of surface water and the lateral migration of pollutants from septic tanks and latrines, and mechanism of dissolution of the clay component of the clayey–sandy layers. | Assessment of the quality of quaternary groundwater under the influence of anthropogenic activities in the low-income neighbourhoods of the Treichville municipality (Abidjan, Côte d’Ivoire) | 10.1007/s42452-020-03478-4 |
2020-09-21 | Background Sweetpotato ( Ipomoea batatas L.) is one of the seven major food crops grown worldwide. Cold stress often can cause protein expression pattern and substance contents variations for tuberous roots of sweetpotato during low-temperature storage. Recently, we developed proteometabolic profiles of the fresh sweetpotatoes (cv. Xinxiang) in an attempt to discern the cold stress-responsive mechanism of tuberous root crops during post-harvest storage. Results For roots stored under 4 °C condition, the CI index, REC and MDA content in roots were significantly higher than them at control temperature (13 °C). The activities of SOD, CAT, APX, O 2 .- producing rate, proline and especially soluble sugar contents were also significantly increased. Most of the differentially expressed proteins (DEPs) were implicated in pathways related to metabolic pathway, especially phenylpropanoids and followed by starch and sucrose metabolism. L-ascorbate peroxidase 3 and catalase were down-regulated during low temperature storage. α-amylase, sucrose synthase and fructokinase were significantly up-regulated in starch and sucrose metabolism, while β-glucosidase, glucose-1-phosphate adenylyl-transferase and starch synthase were opposite. Furthermore, metabolome profiling revealed that glucosinolate biosynthesis, tropane, piperidine and pyridine alkaloid biosynthesis as well as protein digestion and absorption played a leading role in metabolic pathways of roots. Leucine, tryptophan, tyrosine, isoleucine and valine were all significantly up-regulated in glucosinolate biosynthesis. Conclusions Our proteomic and metabolic profile analysis of sweetpotatoes stored at low temperature reveal that the antioxidant enzymes activities, proline and especially soluble sugar content were significantly increased. Most of the DEPs were implicated in phenylpropanoids and followed by starch and sucrose metabolism. The discrepancy between proteomic (L-ascorbate peroxidase 3 and catalase) and biochemical (CAT/APX activity) data may be explained by higher H 2 O 2 levels and increased ascorbate redox states, which enhanced the CAT/APX activity indirectly. Glucosinolate biosynthesis played a leading role in metabolic pathways. Leucine, tryptophan, tyrosine, isoleucine and valine were all significantly up-regulated in glucosinolate biosynthesis. | Proteomic and metabolic profile analysis of low-temperature storage responses in Ipomoea batata Lam. tuberous roots | 10.1186/s12870-020-02642-7 |
2020-09-21 | Background In order to study the relations of hepatocellular functions, weight gain and metabolic imbalance caused by low-dose antibiotics (LDA) via epigenetic regulation of gene transcription, 32 weaned piglets were employed as animal models and randomly allocated into two groups with diets supplemented with 0 or LDA (chlorotetracycline and virginiamycin). Results During the 4 weeks of the experiment, LDA showed a clear growth-promoting effect, which was exemplified by the significantly elevated body weight and average daily gain. Promoter methylome profiling using liquid hybridization capture-based bisulfite sequencing (LHC-BS) indicated that most of the 745 differential methylation regions (DMRs) were hypermethylated in the LDA group. Several DMRs were significantly enriched in genes related with fatty acids metabolic pathways, such as FABP1 and PCK1. In addition, 71 differentially expressed genes (DEGs) were obtained by strand-specific transcriptome analysis of liver tissues, including ALOX15, CXCL10 and NNMT, which are three key DEGs that function in lipid metabolism and immunity and which had highly elevated expression in the LDA group. In accordance with these molecular changes, the lipidome analyses of serum by LC-MS identified 38 significantly differential lipids, most of which were downregulated in the LDA group. Conclusions Our results indicate that LDA could induce epigenetic and transcriptional changes of key genes and lead to enhanced efficiency of lipid metabolism in the liver. | Multi-omics profiling highlights lipid metabolism alterations in pigs fed low-dose antibiotics | 10.1186/s12863-020-00918-3 |
2020-09-17 | Background Abiotic stresses like low temperatures are contributory factors to the variations observed among species during plant germination, growth, and development. The present study evaluated the morphological and genetic responses of maize ( Zea mays L.) seedling to cold shock induced by a one-time exposure to low temperature. Seeds were originally exposed to distilled water at room temperature for 48 h before they were completely submerged in buckets of ice for 0.5, 1.5, 3, 6, and 12 h, respectively, and then transferred into Petri dishes. The set up was left on the laboratory bench for an additional 5 days, and plant germination parameters were measured. DNA was extracted and this was followed by RAPD—polymerase chain reaction. Results Significant growth impairment upon exposure to cold shock corresponding to the length of time of exposure was shown. The length of the prominent root significantly reduced upon exposure to a cold shock from 141.8 mm to as low as 91.4 mm in those plants exposed at 1.5 h. The length of the prominent leaf also significantly reduced from 100.6 mm in the control to between 62.6 and 85.5 mm in low-temperature-exposed plants ( p < 0.05), notwithstanding the time of exposure. There were significant reductions in final germination percent in the low-temperature-exposed germinants (35.8–60.5%) when compared to the control (88.5%). The RAPD marker (OPA04) revealed variations in germinated maize seeds after treatment with different duration of low temperatures. The test plantlets treated for 0, 0.5, and 1.5 h have an unrecognizable complementary sequence to the primer OPA04, whereas the primer amplified regions of the genome of test plantlets treated for 3, 6, and 12 h. Primer OPA05 also presented diversity among maize seedlings stressed for various durations of cold shock. Conclusion The existence of genetic variations in the present study has far-reaching effects on the development of maize exposed to varying degrees of cold stress. Though restricted to germination only, they are important because the development of plants begins at the germination stage. These changes may affect the characteristics of economic importance or perhaps impact on the physiology of the maize plant eventually. | Variations in growth and genetic properties of Zea mays L. germinants exposed to cold shock | 10.1186/s42269-020-00415-8 |
2020-09-15 | In this work, we propose a bistable vibration energy harvester that can be used for non-resonant low-frequency, low-amplitude excitation. The design exploits magnetic bistability created between a pair of repelling magnets. Unlike base-excited beams, our design relies on placing one magnet on the tip of a cantilever beam having a fixed base, while transversely moving an opposite magnet thereby displacing the beam across its two stable positions with an amplified motion to harvest greater amounts of power by electromagnetic induction. A theoretical model is developed to simulate the dynamic behavior of the system at different excitation frequencies, amplitudes and magnetic gaps in order to assess the effect of the design parameters on the performance. It was found that the proposed design is beneficial and outperforms conventional linear oscillators for a broad range of frequencies, except at the linear resonance frequency. The results are supported experimentally over a range of load resistance. | A bistable electromagnetic energy harvester for low-frequency, low-amplitude excitation | 10.1007/s40430-020-02607-9 |
2020-09-14 | In 2016/2017, H5N8 highly pathogenic avian influenza (HPAI) virus of the Goose/Guangdong lineage spread from Asia to Europe, causing the biggest and most widespread HPAI epidemic on record in wild and domestic birds in Europe. We hypothesized that the wide dissemination of the 2016 H5N8 virus resulted at least partly from a change in tissue tropism from the respiratory tract, as in older HPAIV viruses, to the intestinal tract, as in low pathogenic avian influenza (LPAI) viruses, allowing more efficient faecal-oral transmission. Therefore, we determined the tissue tropism and associated lesions in wild birds found dead during the 2016 H5N8 epidemic, as well as the pattern of attachment of 2016 H5N8 virus to respiratory and intestinal tissues of four key wild duck species. We found that, out of 39 H5N8-infected wild birds of 12 species, four species expressed virus antigen in both respiratory and intestinal epithelium, one species only in respiratory epithelium, and one species only in intestinal epithelium. Virus antigen expression was association with inflammation and necrosis in multiple tissues. The level of attachment to wild duck intestinal epithelia of 2016 H5N8 virus was comparable to that of LPAI H4N5 virus, and higher than that of 2005 H5N1 virus for two of the four duck species and chicken tested. Overall, these results indicate that 2016 H5N8 may have acquired a similar enterotropism to LPAI viruses, without having lost the respirotropism of older HPAI viruses of the Goose/Guangdong lineage. The increased enterotropism of 2016 H5N8 implies that this virus had an increased chance to persist long term in the wild waterbird reservoir. | Enterotropism of highly pathogenic avian influenza virus H5N8 from the 2016/2017 epidemic in some wild bird species | 10.1186/s13567-020-00841-6 |
2020-09-14 | Background The association between long-term exposure to air pollutants, including nitrogen dioxide (NO 2 ), carbon monoxide (CO), sulfur dioxide (SO 2 ), ozone (O 3 ), and particulate matter 10 μm or less in diameter (PM 10 ), and mortality by ischemic heart disease (IHD), cerebrovascular disease (CVD), pneumonia (PN), and chronic lower respiratory disease (CLRD) is unclear. We investigated whether living in an administrative district with heavy air pollution is associated with an increased risk of mortality by the diseases through an ecological study using South Korean administrative data over 19 years. Methods A total of 249 Si-Gun-Gus, unit of administrative districts in South Korea were studied. In each district, the daily concentrations of CO, SO 2 , NO 2 , O 3 , and PM 10 were averaged over 19 years (2001–2018). Age-adjusted mortality rates by IHD, CVD, PN and CLRD for each district were averaged for the same study period. Multivariate beta-regression analysis was performed to estimate the associations between air pollutant concentrations and mortality rates, after adjusting for confounding factors including altitude, population density, higher education rate, smoking rate, obesity rate, and gross regional domestic product per capita. Associations were also estimated for two subgrouping schema: Capital and non-Capital areas (77:172 districts) and urban and rural areas (168:81 districts). Results For IHD, higher SO 2 concentrations were significantly associated with a higher mortality rate, whereas other air pollutants had null associations. For CVD, SO 2 and PM 10 concentrations were significantly associated with a higher mortality rate. For PN, O 3 concentrations had significant positive associations with a higher mortality rate, while SO 2 , NO 2 , and PM 10 concentrations had significant negative associations. For CLRD, O 3 concentrations were associated with an increased mortality rate, while CO, NO 2 , and PM 10 concentrations had negative associations. In the subgroup analysis, positive associations between SO 2 concentrations and IHD mortality were consistently observed in all subgroups, while other pollutant-disease pairs showed null, or mixed associations. Conclusion Long-term exposure to high SO 2 concentration was significantly and consistently associated with a high mortality rate nationwide and in Capital and non-Capital areas, and in urban and rural areas. Associations between other air pollutants and disease-related mortalities need to be investigated in further studies. | Association between long-term exposure to air pollutants and cardiopulmonary mortality rates in South Korea | 10.1186/s12889-020-09521-8 |
2020-09-11 | Background The thermal plasticity of life-history traits receives wide attention in the recent biological literature. Of all the temperature-dependent traits studied, developmental rates of ectotherms are especially often addressed, and yet surprisingly little is known about embryonic responses to temperature, including changes in the thermal thresholds and thermal sensitivity during early development. Even postembryonic development of many cryptically living species is understood superficially at best. Results This study is the first to estimate the exact durations of developmental stages in the cowpea seed beetle C. maculatus from oviposition to adult emergence at five permissive constant temperatures from 20 to 32 °C. Early embryonic development was tracked and documented by means of destructive sampling and subsequent confocal imaging of fluorescently stained specimens. Late embryonic and early larval development was studied with the use of destructive sampling and light microscopy. Well-resolved temporal series based on thousands of embryos allowed precise timing of the following developmental events: formation of the blastoderm; formation, elongation, and retraction of the germ band; dorsal closure; the onset and completion of sclerotization of the cuticle; hatching, and penetration of the first-instar larva into the cowpea seed. Pupation and adult eclosion were observed directly through an incision in the seed coat. The thermal phenotype of C. maculatus was found to vary in the course of ontogeny and different stages scaled disproportionately with temperature, but pitfalls and caveats associated with analyses of relative durations of individual stages are also briefly discussed. Conclusion Disproportionate changes in developmental durations with temperature may have important implications when study design requires a high degree of synchronization among experimental embryos or when the occurrence of particular stages in the field is of interest, as well as in any other cases when development times need to be estimated with precision. This work provides one of the first examples of integration of embryological techniques with ecophysiological concepts and will hopefully motivate similar projects in the future. While experiments with Drosophila continue to be the main source of information on animal development, knowledge on other model species is instrumental to building a broader picture of developmental phenomena. | Stagewise resolution of temperature-dependent embryonic and postembryonic development in the cowpea seed beetle Callosobruchus maculatus (F.) | 10.1186/s12898-020-00318-2 |
2020-09-11 | The valence and spin states of Fe in (Fe,Al)-bearing bridgmanite (bdg) affect its physical properties, which is important for the interpretation of geophysical observations. Currently, tens of studies on the compressibility and spin states of Fe-bearing bdg have been reported. A consensus is that Fe-bearing bdg shows spin transition, which affects its elastic parameters. However, there is a conflict between reports on the compressibility and spin states of (Fe,Al)-bearing bdg in experiments using samples pre-synthesized in a multi-anvil apparatus (MA), and samples directly synthesized in a diamond anvil cell (DAC). There are no reports showing evidence of spin transition of Fe in compression experiments using (Fe,Al)-bearing bdg samples pre-synthesized in a MA, while those synthesized at relatively high pressure (at least above 45 GPa) in a DAC all exhibited the spin transition. Here, we performed synchrotron X-ray diffraction measurements on Mg 0.85 Fe 0.09 Al 0.21 Si 0.86 O 3 and Mg 0.85 Fe 0.14 Al 0.05 Si 0.96 O 3 bdg synthesized at relatively high pressure in a laser-heated DAC from amorphous starting material up to 47 and 56 GPa, respectively, at room temperature. The obtained pressure ( P )–lattice volume (V ) relations show noticeable softening at 22–30 GPa and 35–45 GPa, respectively, which is probably due to the spin transition of Fe. Combining our results and previous reports, we suggest that the lower mantle bdg is capable of containing low-spin Fe 3+ , which questions the general view. Such a transition changes density and may affect the physical properties of bridgmanite such as thermal conductivity and iron partitioning coefficient, thus having profound implications for mantle dynamics, and the chemical composition of the Earth. | Anomalous compressibility in (Fe,Al)-bearing bridgmanite: implications for the spin state of iron | 10.1007/s00269-020-01109-3 |
2020-09-11 | Background The use of obstetric early-warning-systems (EWS) has been recommended to improve timely recognition, management and early referral of women who have or are developing a critical illness. Development of such prediction models should involve a statistical combination of predictor clinical observations into a multivariable model which should be validated. No obstetric EWS has been developed and validated for low resource settings. We report on the development and validation of a simple prediction model for obstetric morbidity and mortality in resource-limited settings. Methods We performed a multivariate logistic regression analysis using a retrospective case-control analysis of secondary data with clinical indices predictive of severe maternal outcome (SMO). Cases for design and validation were randomly selected ( n = 500) from 4360 women diagnosed with SMO in 42 Nigerian tertiary-hospitals between June 2012 and mid-August 2013. Controls were 1000 obstetric admissions without SMO diagnosis. We used clinical observations collected within 24 h of SMO occurrence for cases, and normal births for controls. We created a combined dataset with two controls per case, split randomly into development ( n = 600) and validation ( n = 900) datasets. We assessed the model’s validity using sensitivity and specificity measures and its overall performance in predicting SMO using receiver operator characteristic (ROC) curves. We then fitted the final developmental model on the validation dataset and assessed its performance. Using the reference range proposed in the United Kingdom Confidential-Enquiry-into-Maternal-and-Child-Health 2007-report, we converted the model into a simple score-based obstetric EWS algorithm. Results The final developmental model comprised abnormal systolic blood pressure-(SBP > 140 mmHg or < 90 mmHg), high diastolic blood pressure-(DBP > 90 mmHg), respiratory rate-(RR > 40/min), temperature-(> 38 °C), pulse rate-(PR > 120/min), caesarean-birth, and the number of previous caesarean-births. The model was 86% (95% CI 81–90) sensitive and 92%- (95% CI 89–94) specific in predicting SMO with area under ROC of 92% (95% CI 90–95%). All parameters were significant in the validation model except DBP. The model maintained good discriminatory power in the validation ( n = 900) dataset (AUC 92, 95% CI 88–94%) and had good screening characteristics. Low urine output (300mls/24 h) and conscious level (prolonged unconsciousness-GCS < 8/15) were strong predictors of SMO in the univariate analysis. Conclusion We developed and validated statistical models that performed well in predicting SMO using data from a low resource settings. Based on these, we proposed a simple score based obstetric EWS algorithm with RR, temperature, systolic BP, pulse rate, consciousness level, urinary output and mode of birth that has a potential for clinical use in low-resource settings.. | Development and validation of an obstetric early warning system model for use in low resource settings | 10.1186/s12884-020-03215-0 |
2020-09-11 | The groundwater samples were found to be contaminated with high concentrations of uranium (U) in Punjab state as well as in few other locations of India. U being chemically toxic can deteriorate health when ingested. Hence, there is a need to remove U from contaminated water using an efficient, cheap and user friendly method. A study was initiated to investigate the efficiency of low-cost adsorbents in removing U from water. Seven adsorbents were screened for U removal efficiency, among which fly ash (FA) and tea waste (TW) were found to have better removal efficiency. Solid–liquid contact time and solution pH were optimized to establish conditions for better U removal efficiency. The U adsorption on FA and TW followed pseudo-second-order kinetics with rate constant values 4.63 g/mg/min and 15.63 g/mg/min, respectively. FA and TW had the highest U removal capability at pH 6 and pH 4, respectively. The U sorption data were fitted with Freundlich and Dubinin–Radushkevich isotherm models. The U adsorption on FA and TW is found to be a physical process with mean free energy ( E ) values less than 8 kJ/mol. Theoretically calculated maximum adsorption capacity values indicate that FA is a better adsorbent as compared to TW, which has been further confirmed experimentally. The U adsorption on both the adsorbents has interference from Ca 2+ and no interference from Fe 3+ at tested U concentrations. It is also found that FA and TW are effective in decontaminating U from spiked real groundwater samples to below the WHO (Guidelines for drinking water quality, 4th ed, vol 1, World Health Organization, Geneva, 2011) limit. | An investigation on the efficiency of low-cost adsorbents in removing uranium from water samples | 10.1007/s13201-020-01299-9 |
2020-09-11 | Background Atrial fibrillation and heart failure are common coexisting conditions requiring hospitalisation for heart failure and death. Pulmonary vein isolation is a well-established option for symptomatic atrial fibrillation and for atrial fibrillation concomitant with heart failure with reduced left ventricular ejection fraction. Recently, pulmonary vein isolation using cryoballoon showed non-inferiority to radiofrequency ablation with respect to the treatment of patients with drug-refractory paroxysmal atrial fibrillation. However, the effectiveness of acute-phase rhythm control by semi-urgent pulmonary vein isolation using cryoballoon in patients with haemodynamically unstable atrial fibrillation storm accompanied with low cardiac output syndrome is unclear. Herein, we present a case in which semi-urgent pulmonary vein isolation using cryoballoon was effective for acute-phase rhythm control against drug-resistant and haemodynamically unstable repetitive atrial fibrillation tachycardia accompanied with low cardiac output syndrome. Case presentation A 57-year-old man was hospitalised for New York Heart Association functional class 4 heart failure with atrial fibrillation tachycardia and reduced left ventricular ejection fraction of 20% accompanied with low cardiac output syndrome-induced liver damage. The haemodynamics collapsed during atrial fibrillation tachycardia, which had become resistant to intravenous amiodarone and repeated electrical cardioversions. In addition to atrial fibrillation, atrial tachycardia and common-type atrial flutter appeared on day 3. Multiple organ failure progressed gradually due to haemodynamically unstable atrial fibrillation tachycardia storm accompanied with low cardiac output syndrome. On day 4, to focus on treatment of heart failure and multiple organ failure, semi-urgent rescue pulmonary vein isolation using cryoballoon to atrial fibrillation and cavotricuspid isthmus ablation to common-type atrial flutter were performed for acute-phase rhythm control. Soon after the ablation procedure, atrial fibrillation and common-type atrial flutter were lessened, and sinus rhythm was restored. A stable haemodynamics was successfully achieved with the improvement of hepatorenal function. The patient was discharged on day 77 without complications. Conclusions This case demonstrates that acute-phase rhythm control by semi-urgent pulmonary vein isolation using cryoballoon could be a treatment option in patients with haemodynamically unstable atrial fibrillation tachycardia storm accompanied with low cardiac output syndrome, which is refractory to cardioversion and drug therapy. | Semi-urgent pulmonary vein isolation using cryoballoon for haemodynamically unstable atrial fibrillation storm in a patient with low cardiac output syndrome: a case report | 10.1186/s12872-020-01682-z |
2020-09-10 | Background The Schmorl’s nodes (SNs) are defined as the herniation of the intervertebral disc into the vertebral body. Endplate fractures around the Schmorl’s node could result in severe back pain that is similar to vertebral compression fractures. The objective of this study was to prospectively analyze the surgical effectiveness and safety of percutaneous vertebroplasty (PVP) for endplate fractures around the SNs. Methods Seventy-one consecutive patients with the fresh endplate fracture around SNs from October 2017 to February 2018 were enrolled in this study. The visual analog scale (VAS) and Oswestry disability index (ODI) scores of low back pain were evaluated in all patients preoperatively, postoperatively, and at 1 month, 6 months, and 1 year after primary single level PVP. Surgery-related data including duration of the operation, injected cement volumes, and surgical complications were recorded. Results Sixty-five patients with fresh endplate fractures around the SNs were treated successfully via percutaneous vertebroplasty. Our study showed that the VAS scores and ODI scores of patients were obviously improved after operation. Cement leakage into the disc space occurred in 5 patients (7.7%), and adjacent segment refractures occurred in 2 patients (3.1%). No other surgical complications, including infections or nerve root injuries were encountered. Conclusions Based on the results of this prospective study, PVP was an effective and safe procedure for endplate fractures around the SNs. Trial registration ChiCTR, ChiCTR1800016453 . Registered 2 June 2018—retrospectively registered, http://www.chictr.org.cn/com/25/historyversionpuben.aspx?regno=ChiCTR1800017602 | Percutaneous vertebroplasty (PVP) to treat specialized type of endplate fractures around the Schmorl’s node: a prospective study of 65 patients | 10.1186/s13018-020-01873-6 |
2020-09-10 | The rapid population growth and industrialisation has contributed to the production of large quantities of solid wastes that should be managed properly. This study was conducted to investigate the generation and composition of solid wastes at different income levels during weekdays and weekends in a particular zone in Palapye municipality (Extension 7), Botswana. The study was conducted through sampling of wastes at source and analysis at the laboratory. In increasing order, the generation rates were 0.17 ± 0.11, 0.17 ± 0.0, 0.10 ± 0.02 and 0.08 ± 0.01 kg/capita/day in high, middle, lodge (commercial) and low income household during weekdays respectively. The corresponding generation rates during weekends were 0.38 ± 0.23, 0.34 ± 0.0, 0.22 ± 0.0 and 0.27 ± 0.21 kg/capita/day, respectively. Food wastes represented the highest composition and in decreasing order was 48.4 ± 24.6, 68.1, 59.4 ± 2.47, and 51.8 ± 5.1% respectively, during weekdays. The corresponding composition during weekends was 73.8 ± 25.7, 86.4, 62.6 ± 39.8 and 49.8%, respectively. The densities of the wastes were 383.5 ± 213, 493.8 ± 454, 580.9 ± 436, and 431 ± 188 kg/m 3 respectively, from high, middle, low- income households and commercial entity during weekdays. The corresponding densities during weekends were 568 ± 105, 270 ± 0.0, 352.8 ± 149 and 833 ± 0.0 kg/m 3 respectively. Indiscriminate wastes disposal were observed at the dumping site which was not controlled and therefore posing as a health hazard to both human beings, animals and the environment in general. To conclude, large quantities of wastes are generated by high income-households and more is produced during weekends with food wastes representing the highest composition. The information from the study can inform the policy makers and public health specialists to plan engineered waste management system for the town. | Generation and composition of municipal solid waste: case study, extension 7, Palapye, Botswana | 10.1007/s42452-020-03496-2 |
2020-09-09 | Kions were introduced onto Cu/SAPO-34 catalysts via the ion-exchange process in order to improve their stability under low-temperature hydrothermal aging. The changes in structure and copper-species contents of these catalysts upon hydrothermal aging were probed in order to investigate their effects on selective catalytic reduction (SCR) activity. For the fresh Cu/SAPO-34 catalysts, K ions had little influence on the chabazite framework but effected their acidities by exchanging with acid sites. After hydrothermal aging, the structural integrity and amount of active sites decreased on pure Cu/SAPO-34. While the K-loaded catalysts showed improved chabazite structure, acidity, and active site conservation with increasing K loading. However, although the 0.7 wt% K catalyst maintained the same crystallinity, active site abundance, and low-temperature SCR activity as the fresh catalyst upon aging, an apparent decrease in SCR activity at high temperature was observed because of the inevitable decrease in the number of Brönsted acid sites. To compensate for the activity disadvantage of K-loaded Cu/SAPO-34 at high temperature, Fe/Beta catalysts were co-employed with K-loaded Cu/SAPO-34, and a wide active temperature window of SCR activity was obtained. Thus, our study reveals that a combined system comprising Fe/Beta and K-loaded Cu/SAPO-34 catalysts shows promise for the elimination of NO x in real-world applications. | Promotional effect of ion-exchanged K on the low-temperature hydrothermal stability of Cu/SAPO-34 and its synergic application with Fe/Beta catalysts | 10.1007/s11783-020-1322-1 |
2020-09-09 | Background Exposure to ionizing radiation induces complex stress responses in cells, which can lead to adverse health effects such as cancer. Although a variety of studies investigated gene expression and affected pathways in human fibroblasts after exposure to ionizing radiation, the understanding of underlying mechanisms and biological effects is still incomplete due to different experimental settings and small sample sizes. Therefore, this study aims to identify the time point with the highest number of differentially expressed genes and corresponding pathways in primary human fibroblasts after irradiation at two preselected time points. Methods Fibroblasts from skin biopsies of 15 cell donors were exposed to a high (2Gy) and a low (0.05Gy) dose of X-rays. RNA was extracted and sequenced 2 h and 4 h after exposure. Differentially expressed genes with an adjusted p -value < 0.05 were flagged and used for pathway analyses including prediction of upstream and downstream effects. Principal component analyses were used to examine the effect of two different sequencing runs on quality metrics and variation in expression and alignment and for explorative analysis of the radiation dose and time point of analysis. Results More genes were differentially expressed 4 h after exposure to low and high doses of radiation than after 2 h. In experiments with high dose irradiation and RNA sequencing after 4 h, inactivation of the FAT10 cancer signaling pathway and activation of gluconeogenesis I , glycolysis I, and prostanoid biosynthesis was observed taking p -value (< 0.05) and (in) activating z-score (≥2.00 or ≤ − 2.00) into account. Two hours after high dose irradiation, inactivation of small cell lung cancer signaling was observed. For low dose irradiation experiments, we did not detect any significant ( p < 0.05 and z-score ≥ 2.00 or ≤ − 2.00) activated or inactivated pathways for both time points. Conclusions Compared to 2 h after irradiation, a higher number of differentially expressed genes were found 4 h after exposure to low and high dose ionizing radiation. Differences in gene expression were related to signal transduction pathways of the DNA damage response after 2 h and to metabolic pathways, that might implicate cellular senescence, after 4 h. The time point 4 h will be used to conduct further irradiation experiments in a larger sample. | Comparison of time and dose dependent gene expression and affected pathways in primary human fibroblasts after exposure to ionizing radiation | 10.1186/s10020-020-00203-0 |
2020-09-07 | Biobased products (biobased materials, bioenergy/biofuels, and biobased chemicals) are the futuristic replacement of fossil-based chemicals and considerably the best way of transiting towards a low-carbon economy (LCE) and which also can simultaneously mitigate the global challenges associated with the depletion of abiotic resources and climate change. Endurance with the biobased products is leading to the development of a biobased economy (BBE). Assessment of environmental sustainability achieved by the production of biobased products is important to understand their decarbonization potential, and all associated impacts with their life cycle and can be measured with life cycle assessment (LCA) tool. Life cycle sustainability assessment (LCSA) combines LCA with life cycle costing (LCC) and social life cycle assessment (sLCA). The framework of this paper is thus designed to provide an insight into biobased products with an overview of LCA as critical tools to measure sustainability. LCA methodology and its importance in determining sustainability for biobased products with associated limitations and probable solutions are also discussed. Circular economy (CE) integrating cradle-to-cradle (C2C) approach is also discussed as a promising endeavor to achieve LCE. Graphical abstract | Biobased Products and Life Cycle Assessment in the Context of Circular Economy and Sustainability | 10.1007/s42824-020-00007-x |
2020-09-04 | In this work, two quinoxline type monomers, 10,14-bis(4-octyl-2-thienyl)-dipyrido[3,2- a :2′,3′- c ] [1, 2, 5] thiadiazolo[3,4- i ] quinoxaline (OTPTP) and 10,14-bis(4-octyl-2-thienyl)-dibenzo[ a, c ][1,2,5]thiadiazolo [3,4- i ] quinoxaline (OTBTP) were prepared, and the electrochromic features of their polymer films that were synthesized on the ITO glass surface by electrochemical polymerization were studied. The electronic characteristics of two different electron-withdrawing groups and their influences on the electrochemical polymerization of monomers and electrochromic performance of the obtained polymers were observed. The electronic performance of monomers illustrated that OTBTP can be polymerized in the lower potential range than OTPTP due to the stronger electron-withdrawing capability of the electron-withdrawing groups in OTPTP which contains two dipyridine units. The UV Visible NIR spectra analysis showed that both polymers, POTPTP and POTBTP, have one broad absorbance band in the region of 400 ~ 1600 nm at the neutral state. The electrochromic analysis revealed that the two polymer films exhibited reasonable optical contrasts in the infrared region of 1000 ~ 1600 nm with low response time (about 5 s) and low band gap. | Low band gap polymers based on the electrochemical polymerization of Phenazine: studies on the color changing ability in near-infrared region | 10.1007/s10965-020-02266-3 |
2020-09-04 | Purpose The poor permeability of new drug candidates across intestinal epithelial membranes complicates their development in oral form. This study investigated the potential of cell-penetrating peptides (CPPs) to improve the intestinal permeation and absorption of low-permeable low-molecular-weight (low-MW) drugs. Methods The in vitro epithelial permeation of six different drugs (metformin, risedronate, zanamivir, methotrexate [MTX], tacrolimus, and vincristine [VCR]) across Caco-2 cell monolayers was examined in the presence and absence of L- or D-penetratin, and the correlation between permeation enhancement efficiency and the properties of tested drugs was analyzed. In addition, a rat closed ileal loop absorption study was conducted to determine the in vivo effects of penetratin. Results MTX and VCR efficiently permeated Caco-2 monolayers in the presence of L- and D-penetratin, suggesting that CPPs enhanced the epithelial permeation of drugs with relatively high molecular weight and resultant limited intrinsic permeability. The in vivo rat closed ileal loop absorption study revealed the stimulatory effect of L- and D-penetratin on the intestinal absorption of MTX and VCR. Conclusions CPPs are useful as oral absorption enhancers for low-permeable drugs. | Evaluation of Cell-Penetrating Peptides as Versatile, Effective Absorption Enhancers: Relation to Molecular Weight and Inherent Epithelial Drug Permeability | 10.1007/s11095-020-02874-0 |
2020-09-03 | Background Based on the previous investigation in our institution, the incidence of intraoperative hypothermia in neonates was high. Since September 1st, 2019, the recommendation had been launched to utilize ≤1 L/min fresh gas flow during the neonates’ surgical procedure. We therefore intended to evaluate the association between low fresh gas flow anesthesia and the occurrence of hypothermia in neonates undergoing digestive surgeries. Methods A retrospective chart review, before-after study was conducted for neonates who underwent digestive surgeries. The primary outcomes were the incidence of hypothermia. The secondary outcomes included hospital mortality, the value of lowest temperature, blood loss, mean body temperature during the surgery, the length of hypothermia during the surgery and postoperative hospital length-of- stay (PLOS). Results 249 neonates fulfilled the eligibility criteria. The overall incidence of intraoperative hypothermia was 81.9%. The low fresh gas flow anesthesia significantly reduced the odds of hypothermia [routine group: 149 (87.6%) versus low flow group: 55 (69.6%); p < 0.01]. Moreover, the low fresh gas flow anesthesia could reduce the length of hypothermia [routine group: 104 mins (50, 156) versus low flow group: 30 mins (0,100); p < 0.01], as well as elevate the value of lowest temperature for neonates [routine group: 35.1 °C (34.5, 35.7) versus low flow group: 35.7 °C (35.3, 36); p < 0.01]. After adjustment for confounding, low fresh gas flow anesthesia and the length of surgical time were independently associated with intraoperative hypothermia. Conclusions Low fresh gas flow anesthesia is an effective way to alleviate hypothermia in neonates undergoing open digestive surgery. | The low fresh gas flow anesthesia and hypothermia in neonates undergoing digestive surgeries: a retrospective before-after study | 10.1186/s12871-020-01140-5 |
2020-09-03 | Background The use of molecular diagnostics has revealed an unexpectedly large number of asymptomatic low-density malaria infections in many malaria endemic areas. This study compared the gains in parasite prevalence obtained by the use of ultra-sensitive (us)-qPCR as compared to standard qPCR in cross-sectional surveys conducted in Thailand, Brazil and Papua New Guinea (PNG). The compared assays differed in the copy number of qPCR targets in the parasite genome. Methods Plasmodium falciparum ( Pf ) and Plasmodium vivax ( Pv ) parasites were quantified by qPCR amplifying the low-copy Pf_ and Pv _18S rRNA genes or the multi-copy targets Pf _varATS and Pv _mtCOX1. Cross-sectional surveys at the three study sites included 2252 participants of all ages and represented different transmission intensities. Results In the two low-transmission areas, P. falciparum positivity was 1.3% (10/773) (Thailand) and 0.8% (5/651) (Brazil) using standard Pf _18S rRNA qPCR. In these two countries, P. falciparum positivity by Pf_ varATS us-qPCR increased to 1.9% (15/773) and 1.7% (11/651). In PNG, an area with moderate transmission intensity, P. falciparum positivity significantly increased from 8.6% (71/828) by standard qPCR to 12.2% (101/828) by us-qPCR. The proportions of P. falciparum infections not detected by standard qPCR were 33%, 55% and 30% in Thailand, Brazil and PNG. Plasmodium vivax was the predominating species in Thailand and Brazil, with 3.9% (30/773) and 4.9% (32/651) positivity by Pv _18S rRNA qPCR. In PNG, P. vivax positivity was similar to P. falciparum , at 8.0% (66/828). Use of Pv _mtCOX1 us-qPCR led to a significant increase in positivity to 5.1% (39/773), 6.4% (42/651) and 11.5% (95/828) in Thailand, Brazil, and PNG. The proportions of P. vivax infections missed by standard qPCR were similar at all three sites, with 23%, 24% and 31% in Thailand, Brazil and PNG. Conclusion The proportional gains in the detection of P. falciparum and P. vivax infections by ultra-sensitive diagnostic assays were substantial at all three study sites. Thus, us-qPCR yields more precise prevalence estimates for both P. falciparum and P. vivax at all studied levels of endemicity and represents a significant diagnostic improvement. Improving sensitivity in P. vivax surveillance by us-qPCR is of particular benefit, because the additionally detected P. vivax infections signal the potential presence of hypnozoites and subsequent risk of relapse and further transmission. | Utility of ultra-sensitive qPCR to detect Plasmodium falciparum and Plasmodium vivax infections under different transmission intensities | 10.1186/s12936-020-03374-7 |
2020-09-03 | In many quantum quench experiments involving cold atom systems the post-quench phase can be described by a quantum field theory of free scalars or fermions, typically in a box or in an external potential. We will study mass quench of free scalars in arbitrary spatial dimensions d with particular emphasis on the rate of relaxation to equilibrium. Local correlators expectedly equilibrate to GGE; for quench to zero mass, interestingly the rate of approach to equilibrium is exponential or power law depending on whether d is odd or even respectively. For quench to non-zero mass, the correlators relax to equilibrium by a cosine-modulated power law, for all spatial dimensions d , even or odd. We briefly discuss generalization to O ( N ) models. | Quantum quench and thermalization to GGE in arbitrary dimensions and the odd-even effect | 10.1007/JHEP09(2020)027 |
2020-09-03 | In this paper, the importance of Lithocodium–Bacinella facies (LB facies) as reservoir rock in the Lower Cretaceous carbonates of the Persian Gulf will be addressed. The studied interval belongs to the reservoir zone of upper Fahliyan Formation, which occurs in one of the giant offshore oilfields. A detailed examination of a continuous core (58 m) from this formation allows clarifying the relationship between facies distribution, diagenetic evolution, and porosity development in function of relative sea level changes. Seven facies types are identified based on core descriptions and microfacies analysis. These facies are interpreted to have been deposited in lagoonal, shoal, and open marine settings during Valanginian–Hauterivian times. Petrographic studies and stable carbon and oxygen isotope analyses indicate that these facies have been affected by different diagenetic processes, starting with early marine diagenesis and followed by meteoric and/or burial diagenesis. Based on facies stacking patterns and evidence of subaerial exposures, four high-frequency sequences are interpreted in terms of variations in accommodation space. Combination of facies analysis, diagenetic studies and poroperm data reveals (with the exception of sequence I) that the lower transgressive and the upper highstand intervals of these sequences show different facies types, diagenetic modifications and reservoir properties. The transgressive system tracts (TST’s) correspond to tight zones (Z-1, 3, 5), with poor reservoir quality ( Φ < 15% and K < 1 md). These intervals are composed of an alternation of open to restricted marine facies. The facies are characterized by extensive bioturbation, high clay content (argillaceous limestones), displaying marine (micritization) and shallow to deep burial diagenetic processes (pyrite mineralization and solution seams). The reservoir intervals preferentially occur within the highstand system tracts (HST’s), which are commonly composed of vertically stacked Lithocodium-Bacinella facies. This facies with aggradational patterns is capped by subaerial exposure surfaces at the top of the sequences and is associated with leaching and cementation. Meteoric dissolution during subaerial exposure resulted in the formation of vuggy and moldic pores as the main pore types in these system tracts, which survived in significant amounts until present-day. Therefore, the LB facies usually have greater than 15% porosity and 1 md permeability. Diagenetic studies in these units show that the marine diagenesis was interrupted by subaerial exposure and meteoric diagenesis before burial and development of stylolites. Our findings show that despite the uncertain taxonomy and paleoenvironmental setting of Lithocodium aggregatum and Bacinella irregularis, the LB facies has great reservoir importance. | Diagenesis and reservoir characteristics of the Lithocodium–Bacinella facies in a Lower Cretaceous reservoir, eastern Persian Gulf Basin | 10.1007/s10347-020-00608-7 |
2020-09-01 | Abstract The paper analyzes the nature of constant low-temperature impact toughness in low-carbon low-alloy 10Mn2VNbAl steel after helical rolling at 850°C. The analysis shows that when rolled, the steel changes the electronic spectrum via shifting its low-energy states in the reciprocal space of lattice curvature to higher levels which are vacant in the initial material. Such interstitial states provide the growth of interstitial bainite islands capable for adaptive rotations under shock loads, and this makes the rolled steel constant in low-temperature impact toughness up to T = –70 °C. | Nanoscale Mesoscopic Structural States in Low-Alloy Steels for
Martensitic Phase Formation and Low-Temperature Toughness
Enhancement | 10.1134/S1029959920050021 |
2020-09-01 | LiFePO 4 /C was prepared by employing coprecipitation method and carbothermal reduction method using FeSO 4 with different purity as the iron source. The purity of FeSO 4 has a great influence on the morphology of FePO 4 , but has little effect on the morphology of LiFePO 4 /C. The cycling performance decreases with the decrease of purity, and purity has a significant effect on the specific discharge capacities at low temperature. The specific discharge capacities of the five samples at − 20 °C and 0.5 C were 85.3, 74.2, 65.5, 60.4, and 50.1 mAh g −1 , and the capacity retention rates were 53.3%, 47.1%, 42.9%, 38.7%, and 31.9%, respectively. Full battery low temperature performance test results validate the test results of coin cell. The Li + diffusion coefficients are 4.53 × 10 −13 , 2.02× 10 −13 , 4.73 × 10 −14 , 2.34× 10 −14 , and 8.56 × 10 −15 cm 2 s −1 , respectively. D Li + is reduced two orders of magnitude with reduction of raw material purity. This is mainly because the low-purity FeSO 4 contains a large amount of Ti, which enters the LiFePO 4 /C crystal lattice, causing the lattice distortion to block the lithium ion diffusion channel. Therefore, improving the purity of raw materials is an important method to improve the low temperature performance of LiFePO 4 /C. | Effect of FeSO4 purity on low temperature performance of LiFePO4/C | 10.1007/s11581-020-03594-6 |
2020-09-01 | Abstract Distillation columns can have high economic impact on small-scale ethanol production because their capital cost and, therefore, a lower investment in this equipment may turn it more feasible. The present work aims to assess the substitution of stainless steel and borosilicate glass by polymeric materials in the manufacturing of distillation columns. A decision tree was proposed, considering chemical, mechanical, thermal, and economic aspects. In addition, a life cycle assessment (LCA) was used to evaluate potential reduction on environmental impacts from columns manufactured with polymeric material. Tests were performed to investigate chemical resistance, including determination of the degree of swelling and characterizations by X-ray diffraction, Fourier-transform infrared, and exploratory scanning calorimetry. Mechanical properties were evaluated by 3-point bending tests. Polymeric materials were selected due to their lower cost in comparison with stainless steel, e.g., polypropylene, high-density polyethylene, and glass fiber-reinforced polyester resin. Results showed satisfactory chemical and mechanical resistance of these three polymers after contact with ethanol, and a 68% reduction in capital cost related to a manufacturing of distillation column with polypropylene. LCA results showed that replacing stainless steel and borosilicate glass by polypropylene in distillation column manufacturing would result in lower environmental impacts in all impact categories considered. A reduction in CO 2 eq emissions of 85% and 59% was observed when polypropylene replaced stainless steel and borosilicate glass, respectively. Graphic abstract | Low-cost small-scale distillation column: assessment of polymeric materials on its economic, chemical, mechanical, and environmental performance | 10.1007/s10098-020-01897-w |
2020-09-01 | When the supercapacitor (SC) adopts electrolyte with solvent, the desolvation mechanism in the charging process is helpful for the electrode material to adsorb more electrolyte ions and improve the capacitance. However, the desolvation effect is temperature dependent, and it is difficult to achieve at low temperature. In this work, we find that the existence of a large number of submicropores (0.7–2 nm) in activated carbon greatly improves the SC performance at − 40 °C. The capacitance retention ratio can reach up to 90% compared with the value at 25 °C. We reveal both experimentally and theoretically a “gradual desolvation mechanism” from the thermal dynamic perspective. The solvent molecules energetically prefer to be removed from the solvated ion step by step in the submicropore. At the same time, we also found that the functionalized carbon nanosponge materials (FCNSs) with most of the submicro- and mesopore structure deliver a high specific capacitance of 131 F g −1 , the capacitance retention ratio at − 40 °C can be about 100% at increased current densities of 1–10 A g −1 . Moreover, the FCNSs also show excellent cycling performance at − 40 °C with no capacitance fading over 5000 cycles at 5 A g −1 . Graphical abstract | Thermal dynamic study of the gradual desolvation in submicropores for carbon-based supercapacitor at low temperature | 10.1007/s11581-020-03575-9 |
2020-09-01 | Abstract To meet the corrosion challenge of pipeline steel under complex mixed cases, the corrosion behavior of X65 steel joints welded by employing three low-temperature phase transformation welding wires was investigated. The low temperature phase transformation electrodes welded joints were exposed to saturated CO 2 aqueous solution containing H 2 S of different pH values for electrochemical corrosion test. The Potentiodynamic polarization curve, Electrochemical Impedance Spectroscopy (EIS) and corrosion morphology were analyzed. The results showed that the Cr and Ni element within joints can enhance the corrosion resistance. The corrosion resistance of the welded joint is improved as the pH of etching liquid increases. The corrosion mechanism was further revealed. | Electrochemical Corrosion Behavior of X65 Pipeline Steel Joints Welded by Low Temperature Phase Transformation Electrodes | 10.1134/S1027451020050407 |
2020-09-01 | A novel circulation process of electrolytic manganese metal (EMM) production with low-grade manganese oxide ores (LGMO) and high-sulfur manganese ores (HSMO) was studied and developed. The unit operations mainly include dissolution of LGMO, purification of leach liquor and electrolysis for EMM preparation. Based on the theoretical thermodynamic analysis, a reductive roasting-acid leaching process for utilizing LGMO using HSMO as reductant was investigated. The leaching efficiency of Mn and Fe could get to 97.30% and 17.50% with conditions set as following, which have all been verified through a series of experiments: the material ratio of 1.67:1 (mass ratio of HSMO to LGMO, w/w), roasting temperature of 600 °C for 60 min, L / S ratio of 5:1, stirring speed of 150 rpm, sulfuric acid concentration of 1.0 mol/L and the leaching temperature of 60 °C for 35 min. Meanwhile, the reduction roasting-acid leaching process applies to the Mn extraction for assorted manganese dioxide ores in general. Furthermore, the leach liquor was purified in two steps, and following a scale-up electrolysis process was implemented to prepare EMM from the purified liquors. The uniform and dense α-Mn with bcc crystal structure, meeting the requirement of metallurgical industry standard (YB/T 051-2003), could be stably produced in 9-day incessant ongoing test. | A Novel Circulation Process to Effectively Produce Electrolytic Manganese Metal (EMM) with Low-Grade Manganese Oxide Ores and High-Sulfur Manganese Ores | 10.1007/s13369-020-04656-7 |
2020-09-01 | Thermal analysis of the binary system (Al(NO 3 ) 3 )–(Cu(NO 3 ) 2 ) of different ratios was performed by using differential scanning calorimetry and thermogravimetric analysis. The eutectic temperature of the binary salt mixture was determined to be 65 °C. Moreover, the degradation temperature, specific heat, latent heat of fusion and thermal stability were reported, respectively. Further, this work focuses on synthesising low-temperature salt mixtures comprised of aluminium nitrate non-hydrate (Al(NO 3 ) 3 ) and copper nitrate hydrate (Cu(NO 3 ) 2 ) of varying compositions (60:40, 50:50, 55:45 and 57.5:42.5), respectively, which are optimised using Design of Expert v13. The performance of the binary salt mixture was determined from the results obtained from thermal stability measurements after the exposure of salt mixture to 120 h at a higher temperature. The results showed that the novel binary molten salt mixtures exhibit decomposition at 215 °C and the latent heat was found to increase from 17.7 to 20.73 J g −1 with the increase in aluminium nitrate composition with excellent repeatability after three sets of experiments. The average specific heat of binary molten salt mixture was observed from 2.73 to 2.13 J g −1 K −1 . The optimal molar ratio of binary molten salts is found to be 60:40 (Al/Cu) from the obtained results. Field emission scanning electron microscopy and energy-dispersive X-ray showed a uniform distribution of both the salts in the mixture. The average specific heat of the optimal molar ratio was 21.8% higher compared to other molar ratios, indicating the most promising material to be used in solar applications. | Low-melting-temperature binary molten nitrate salt mixtures for solar energy storage | 10.1007/s10973-020-09683-y |
2020-09-01 | Abstract— The titanium alloy Ti–6Al–4V with strongly nonequilibrium α- and β-phases has been studied for the first time. For this, it was subjected to cross-helical rolling (CHR) at T = 1000°C (above the polymorphic transformation temperature), and then quenched in water in order to partially preserve vanadium in the α-phase, and aluminum in the β-phase. Under active uniaxial tension, the non-equilibrium VT6 alloy was deformed in the absence of strain hardening at room temperature. Alloys treated with CHR below the polymorphic transformation temperature showed traditional parabolic hardening. The non-equilibrium of the VT6 alloy caused a strong increase in its impact toughness at low temperatures down to T = –70°C. The fatigue life of a nonequilibrium alloy has doubled. If the initial alloy has ductile-brittle fracture at low negative temperatures, then the nonequilibrium alloy deforms viscously with all signs of structural turbulence. Structural turbulence in a nonequilibrium alloy manifests itself in the temperature range from 20 to –70°C, during deformation of 3D-printed samples, under conditions of shock separation of diffusion-sintered multilayer VT6 alloy packets. | Fractography, Fracture Toughness and Structural Turbulence Under Low-Temperature Shock Loading of a Nonequilibrium Titanium Alloy Ti–6Al–4V | 10.3103/S0025654420050155 |
2020-09-01 | Materials with intrinsically low thermal conductivity are of fundamental interests. Here we report a new sort of simple one-dimensional (1D) crystal structured bismuth selenohalides (BiSeX, X = Br, I) with extremely low thermal conductivity of ∼0.27 W m −1 K −1 at 573 K. The mechanism of the extremely low thermal conductivity in 1D BiSeX is elucidated systematically using the first-principles calculations, neutron powder-diffraction measurements and temperature tunable aberration-corrected scanning transmission electron microscopy (STEM). Results reveal that the 1D structure of BiSeX possesses unique soft bonding character, low phonon velocity, strong anharmonicity of both acoustic and optical phonon modes, and large off-center displacement of Bi and halogen atoms. Cooperatively, all these features contribute to the minimal phonon transport. These findings provide a novel selection rule to search low thermal conductivity materials with potential applications in thermoelectrics and thermal barrier coatings. 本征低热导率材料的研究具有重要的科学意义, 已引起广泛关注. 本工作报道了一类具有简单一维晶体结构的超低热导率材料: 铋硒卤族化合物(BiSeX, X = Br, I). 研究发现, BiSeI的热导率在573 K仅为∼0.27 W m −1 K −1 , 达到了最低本征热导率的理论极限值. 本研究采用第一性原理计算结合粉末中子衍射和变温球差扫描透射电子显微镜表征, 深入探究了其超低热导率的机制. 研究表明, BiSeX的一维结构赋予了材料低热导特性: 弱的成键特性、 低的声子速度、 声学支和光学支的强非简谐性以及Bi和卤族元素较大的偏移效应, 从而有效阻碍了声子输运, 使得BiSeX具有超低的热导率. 本研究提出了在具有一维结构的材料中寻找低传导特性的新思路, 该研究思路在热电材料和热障涂层材料等低热传导需求领域中具有广阔的应用前景. | Extremely low thermal conductivity from bismuth selenohalides with 1D soft crystal structure | 10.1007/s40843-020-1407-x |
2020-09-01 | The effects of temperature on low cycle fatigue (LCF) behavior of Superni 263 superalloy in the solution annealed plus aged state were examined between 298 and 1023 K. The initial microstructure consisted of intragranular spherical γ ʹ (22 nm), intergranular M 23 C 6 carbides and a few un-dissolved primary MC particles. Strain-controlled LCF tests were performed at a strain rate of 10 −3 s −1 . Correlations between the initial microstructure, macroscopic cyclic deformation, fatigue life, crack initiation and propagation modes, evolving deformation substructure and phase changes have been attempted. Cyclic stress response displayed a marked variation in its temperature dependence. In general, the alloy exhibited initial hardening followed by very slight softening up to 473 K, continuous hardening to a maximum stress in between 573 and 873 K, and initial hardening succeeded by rapid softening at and above 923 K. Dynamic Strain Ageing (DSA) was noticed during 573–923 K. In the DSA domain, the alloy exhibited pronounced cyclic hardening at 673 K, displayed planar slip, stacking faults, high dislocation density and shearing of γ ʹ. The macroscopic features revealed serrated flow in the plastic deformation portions of stress–strain hysteresis loops and inverse temperature dependence of maximum stress and inelastic strain generated at half-life. Fresh precipitation of γ ʹ occurred at 973 K and 1023 K during LCF testing while prior existing γ ʹ coarsened marginally above 923 K. The operating deformation mechanisms of γ ʹ were identified and correlated with microscopic and macroscopic aspects. LCF life displayed a maximum at ~ 473 K and the reduction in life above 473 K was attributed to the deleterious effects of DSA and oxidation. | Comprehensive Assessment of Low Cycle Fatigue Behavior of Nickel-Base Superalloy Superni 263 in the Range 298–1023 K | 10.1007/s41403-020-00095-w |
2020-09-01 | Mn–Ce–VO x /TiO 2 (MnCeVTi), Mn–CeO x /TiO 2 (MnCeTi) and Mn–VO x /TiO 2 (MnVTi) nanocomposites as SCR DeNO x catalysts were synthesized by a modified sol–gel method. All catalysts shows high NO x conversion of over 90% at low temperature between 125 and 200 °C with GHSV of 30,000 h −1 . MnCeVTi catalyst demonstrates the highest NO x conversion and produces the least byproduct N 2 O at 110–310 °C. The co-presence of Ce, V and Mn inhibits the growth of rutile, decreases crystallinity of anatase TiO 2 and manganese oxides, reduces grain size, increases BET specific surface area and pore volume. There are most chemisorbed oxygen, appropriate Mn 3+ /Mn 4+ and the synergistic effect of Ce and V on MnCeVTi sample. The acid sites on MnCeVTi are most below 280 °C and in widest temperature range. Lewis acid sites play a leading role in SCR reaction on MnCeVTi catalyst. These helps to optimize the SCR catalytic performance of MnCeVTi, on which E-R and L–H mechanism may coexist in the reaction. | Synthesis and Characterization of Mn–Ce–VOx/TiO2 Nanocomposite for SCR of NOx at Low Temperatures: Role of Mn, Ce and V Oxide | 10.1007/s11244-020-01315-x |
2020-09-01 | Abstract The magneto-impedance response in Co 35 Fe 65 /Cu/Co 35 Fe 65 thin film magneto-impedance cells deposited by the thermal evaporation method has been studied with single and bilayer structures at the substrate temperature 300 K and 150 K. While the thin film deposited at 300 K has BCC structure, the amorphous character is dominant for 150 K deposited ones. Entire films show soft magnetic behavior with high saturation magnetization (M S ) and low coercive field (H C ). Bilayer thin film structure reveals higher magneto-impedance values than single-layer thin films. The relation between the magneto-impedance effect and layered structure is discussed in terms of structural growing mechanism and scattering effect. The highest magneto-impedance sensitivity (η) 37%/Oe is observed for the Co 35 Fe 65 /Cu/Co 35 Fe 65 bilayer thin film. The H C and remanence ratio (M R /M S ) values for single layer at 300 K, single and bilayer cells at 150 K are measured as 51, 158 and 253 Oe—0.48, 0.78, and 0.80, respectively. When η with the Soliton wave model is compared with the sample at room temperature, an increase of over 1700% is observed. The difference between the classical growing method at 300 K and the Soliton wave model at 150 K is the evidence of the logic of the work performed and its accuracy. The relatively high sensitivity is connected with interlayer usage and low temperature-smaller particle size in Soliton model growth. The observed findings are of practical importance to develop future technological magnetic sensor applications with high sensitivity. Graphic Abstract | Magneto-Impedance in Co35Fe65/Cu/Co35Fe65 Single and Bi-layer Thin Films | 10.1007/s13391-020-00237-w |
2020-09-01 | Abstract A review of techniques for recycling dispersed waste of ferroalloy production is conducted. The formation and accumulation of cyclone dust (catch product of crushing or CPC), formed during the grinding and fractionation of ferroalloys is considered. The drawbacks of the known techniques of handling this dust are shown. The possibility of obtaining commercial nitrided hardeners from CPCs and off-spec ferroalloy fines by self-propagating high-temperature synthesis (SPHTS) is studied. The proposed metallurgical SPHTS is used to develop the technology and show the possibility of bulk production of nitrided ferrosilicon, ferrovanadium, ferrochrome, and other composites in demand on the global market. The materials made by SPHTS have better quality than the nitrided ferroalloys made by the common furnace technique; in particular, the former contain less hydrogen, oxygen, and other impurities, and are denser, stronger, more porous, etc. The production of nitrided ferroalloys and composite hardeners by metallurgical SPHTS is developed using the production facilities of the Etalon scientific and technological production company, which includes the potential of annually processing up to 5000 t of cyclone dust of ferrosilicon and other alloys. The new approach to adopting SPHTS in practice is developed, and the possibility of utilizing synthesized products in metallurgy shown. The manufactured products are intended for use mainly as alloying additives in the smelting of transformed, rail, stainless, high-strength structural, and other steels and alloys. Another demanding consumer of composite SPHTS metal materials is the production of refractories. The modification of conventional refractories used in the smelting of cast iron, steel, and nonferrous metals with new composite SPHTS materials based on nitrides, borides, carbides, and other hard-to-melt compounds allows making refractories much more enduring and cut the expenses for them. | Recycling Dispersed Waste of Ferroalloy Production on the Basis of Metallurgical Self-Propagating High-Temperature Synthesis | 10.3103/S0967091220090089 |
2020-09-01 | COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches) is an experiment employing cryogenic calorimeters, dedicated to direct dark matter search in underground laboratories. Its goal is to cross-check the annual modulation signal the DAMA collaboration has been detecting for about 20 years (Bernabei et al. in Nucl Part Phys Proc 303–305:74–79, 2018. https://doi.org/10.1016/j.nuclphysbps.2019.03.015 ) and which has been ruled out by other experiments in certain dark matter scenarios. COSINUS can provide a model-independent test by the use of the same target material (NaI), with the additional chance of discriminating $$\beta /\gamma$$ β / γ events from nuclear recoils on an event-by-event basis, by the application of a well-established temperature sensor technology developed within the CRESST collaboration. Each module is constituted by two detectors: the light detector, that is a silicon beaker equipped with a transition edge sensor (TES), and the phonon detector, a small cubic NaI crystal interfaced with a carrier of a harder material (e.g. $$\hbox {CdWO}_4$$ CdWO 4 ), also instrumented with a TES. This technology had so far never been applied to NaI crystals because of several well-known obstacles, and COSINUS is the first experiment which succeeded in operating NaI crystals as cryogenic calorimeters. Here, we present the COSINUS project, describe the achievements and the challenges of the COSINUS prototype development and discuss the status and the perspectives of this NaI-based cryogenic frontier. | COSINUS: Cryogenic Calorimeters for the Direct Dark Matter Search with NaI Crystals | 10.1007/s10909-020-02464-9 |
2020-09-01 | Technology for low-temperature carbonitriding combined with high temperature tempering of cold-worked die steel 6Kh4M2FS (DI55) is proposed. The high efficiency of a paste-like coating based on amorphous carbon and nitrogen-containing components (carbamide and potassium ferricyanide) during die steel cyaniding in the temperature range from 500 to 580°C is demonstrated. The effect of thermochemical treatment regimes on diffusion layers formed on steel, their phase composition, and properties is investigated. | Pack Cyaniding of Steel 6Kh4M2FS in Order to Increase Heavily-Loaded Die Durability | 10.1007/s11041-020-00565-6 |
2020-09-01 | Carbonate reservoirs in Asmari block of Missan oilfield are characterized by complex geological characteristics. Temporary plugging is commonly used for effective damage control caused by the working fluid when drilling in such complex multi-pressure reservoirs and for preventing leakage, blowout, and collapse in long open hole wells. In this paper a new temporary plugging drilling fluid formulation system is proposed, designed for the low permeability carbonate reservoir containing H 2 S and CO 2 in the target block. The system contains a specially designed acid-soluble temporary plugging agent DSK-1 combined with HCOONa and modified biopolymer VS-A flow pattern regulator; modified starch water loss reduce agent, and DSP antioxidant. The parameters of the system, including temperature stability, resistance to formation water pollution, inhibition capacity, and stability to acids and acid gases, were evaluated in a series of experimental tests. The plugging ability was evaluated by experiments on cores received from the target block. The results showed that the plugging removal and recovery rate of the drilling fluid system was up to 86.3%, which can effectively meet the target requirements, and provide guidance and reference for the follow-up study of temporary plugging in low permeability carbonate reservoirs. | A New Drilling Fluid System for Temporary Plugging of Low Permeability Carbonate Reservoirs Containing H2S and CO2 | 10.1007/s10553-020-01173-z |
2020-09-01 | In this work, we investigate low-temperature sintering behavior of the 90W-7Ni-3Fe alloy by introducing Sn. The 90W-7Ni-3Fe alloy with different Sn contents (0, 0.5, 1.0 and 1.5 wt.%) was fabricated via vacuum sintering at 1300 °C for 90 min. When 1 wt.% Sn was added, the liquidus temperature of the 90W-7Ni-3Fe alloy decreased from 1477 to 1265 °C, resulting in rapid densification (relative density increased from 77.77 to 98.59%) and an homogeneous liquid-phase sintered microstructure. Electron probe microanalysis (EPMA) and transmission electron microscopy (TEM) observations revealed that, apart from W and the γ -(Ni, Fe) phase, a new Ni 3 Sn 2 phase appeared in the matrix phase. Furthermore, we discuss in detail the formation of the Ni 3 Sn 2 phase based on element selection theory, which can be associated with the larger atomic radius of Sn and with the negative enthalpy of mixing Sn and Ni. Excessive Sn content (1.5 wt.%) led to the increase in Ni 3 Sn 2 phase, and this deteriorated the relative density and tensile strength of the alloy. The 90W-7Ni-3Fe alloy with the addition of 1 wt.% Sn exhibited a maximum tensile strength value (710 MPa), which was much higher than that of the 90W-7Ni-3Fe alloy that was obtained at 1300 °C. Our findings shed light on further research directions and developed a 90W-6.3Ni-2.1Fe-1Sn alloy for low-temperature sintering. | Study on Low-Temperature Sintering Behavior of 90W-7Ni-3Fe Alloys: The Influence of Sn Addition | 10.1007/s11665-020-05055-7 |
2020-09-01 | Abstract In this paper, the microstructures and properties of hot rolled ultra-low carbon steel sheet produced by different compact strip production (CSP) processes were investigated. The softening mechanism was also discussed and the control strategy was proposed in order to obtain optimum properties. Result showed that the average ferrite grain sizes of austenite rolling sheet and multiphase rolling sheet were 31.0 μm and 74.6 μm, respectively. The sheet after austenite rolling had a slightly higher yield and tensile strength while had a 6.3% higher elongation than that of the sheet after multiphase rolling. The higher dislocation in the sheet after multiphase rolling increased the strength while decreased the elongation. The softening mechanism of the sheet after multiphase rolling was the coarsening of ferrite grain. The combined role of {001} and {111} orientation resulted in a slight increase of the r and $${\bar{\text{r}}}$$ r ¯ value in the sheet after multiphase rolling. It was a wise choice to conduct rolling at the Ac 1 temperature in CSP process to increase the grain size and decrease the dislocation density. Then, the strength of the sheets could be further reduced and the elongation could also be improved. Graphic Abstract The microstructures and properties of hot rolled ultra-low carbon steel sheet produced by different compact strip production (CSP) processes were investigated. The average ferrite grain sizes of austenite rolling sheet and multiphase rolling sheet were 31.0 μm and 74.6 μm, respectively. The sheet after austenite rolling had a slightly higher yield and tensile strength while had a 6.3% higher elongation than that of the sheet after multiphase rolling. The higher dislocation in the sheet after multiphase rolling increased the strength while decreased the elongation. The softening mechanism of the sheet after multiphase rolling was the coarsening of ferrite grain. It was a wise choice to conduct rolling at the Ac 1 temperature in CSP process to increase the grain size and decrease the dislocation density. Then, the strength of the sheets could be further reduced and the elongation could also be improved. | Microstructural Characterization and Softening Mechanism of Ultra-Low Carbon Steel and the Control Strategy in Compact Strip Production Process | 10.1007/s12540-019-00392-2 |
2020-09-01 | The development of reliable additive manufacturing (AM) technologies to process metallic materials, e.g. selective laser melting (SLM), has allowed their adoption for manufacturing final components. To date, ensuring part quality and process control for low-volume AM productions is still critical because traditional statistical techniques are often not suitable. To this aim, extensive research has been carried out on the optimisation of material properties of SLM parts to prevent defects and guarantee part quality. Amongst all material properties, defects in surface hardness are of particular concern as they may result in an inadequate tribological and wear resistance behaviour. Despite this general interest, a major void still concerns the quantification of their extent in terms of probability of defects occurring during the process, although it is optimised. Considering these issues, this paper proposes a novel approach to quantify the probability of occurrence of defects in hardness-optimised parts by SLM. First, three process variables, i.e. laser power, scan speed and hatching distance, are studied considering their effect on hardness. Design of Experiments and Response Surface Methodology are exploited to achieve hardness optimisation by controlling process variables. Then, hardness defect probability is estimated by composing the uncertainty affecting both process variables and their relationship with the hardness. The overall procedure is applied to AlSi10Mg alloy, which is relevant for both aerospace and automotive applications. The approach this study proposes may be of assistance to inspection designers to effectively and efficiently set up quality inspections in early design phases of inspection planning. | Defect Probability Estimation for Hardness-Optimised Parts by Selective Laser Melting | 10.1007/s12541-020-00381-1 |
2020-09-01 | An experiment is performed for explosive convergence (collapse) of a cylindrical shell of low carbon steel with a ferrite-perlite structure. It is revealed that during ultra-rapid heating caused by high-speed deformation austenite formation occurs in an unusual sequence: first, free ferrite is converted, then pearlite. The decrease in free ferrite transformation temperature is explained by action of high pressure, as well as by varying degrees of heating steel structural constituents. An effect of barothermal quenching is observed, as a result of which a pearlite-martensite structure forms. | Features of Austenite Formation in Low-Carbon Steel during High Speed Heating Induced by High-Speed Deformation | 10.1007/s11041-020-00560-x |
2020-09-01 | Abstract The influence of modification by low-temperature atmospheric-pressure plasma and steam sterilization on the properties of track membranes based on polyethylene terephthalate is studied. It is found that the action of hot steam under pressure changes the topography of the surface of the membranes with the formation of artifacts in the form of large oval-shaped protrusions with a height of 300–400 nm and a density of up to 0.007 protrusions/μm 2 on the surface, increases the surface roughness by 40% and the wetting angle by 9°–18° for the initial membranes and by 36.8°–39.6° for the membranes modified in plasma, and decreases their surface energy to the initial value of 33 mJ/m 2 . Despite the morphological and structural changes in the surface, sterilization by hot steam under pressure does not lead to any noticeable change in the surface charge and ζ potential of the track membranes. Hot steam under pressure does not promote further crystallization of the membrane, keeping the polymer with a crystalline phase of 40–42%. Thus, to preserve the properties acquired by the membrane after the plasma treatment, it is necessary to search for a different sterilization method (gamma radiation, ethylene oxide sterilization). | The Investigation of the Influence of Low-Temperature Plasma and Steam Sterilization on the Properties of Track Membranes Made of Polyethylene Terephthalate | 10.1134/S2075113320050111 |
2020-09-01 | Ginger is an important Chinese flavoring agent and a traditional herbal medicine. Traditional drying method for ginger may cause severe damage and destroy the chemical and physical qualities. Carbonic maceration (CM) is an efficient and low-cost technology, which can increase the mass transfer rate during drying process and improve the quality indices of ginger. The results showed that CM treatment could produce porous structure and increase the cell membrane permeability, which significantly increases the moisture diffusion and evaporation rate, especially the internal moisture diffusion. The total drying time can be shortened by 42.27 ± 2.78%. Due to the increase of cell membrane permeability, the plant extraction barrier was decreased; thus, the extracted active components were enhanced. Besides, the lower pH environment and inactivation of polyphenol oxidase (PPO) and peroxidase (POD) were also beneficial to increasing the phenol compound retention as well as antioxidant activities. The contents of 6-gingerol, 8-gingerol, 10-gingerol, and 6-shogaol were increased by 20.79%, 37.27%, 36.80%, and 68.53% respectively after CM treatment. The 2,2-diphenyl-1-picrylhydrazyl, ferric-reducing antioxidant power, and oxygen radical absorption capacity values were also increased by 1.33, 1.28, and 1.20 times respectively. Therefore, CM pretreatment could be a suitable alternative technique for improving drying characteristics and preserving nutritional values of agro-based product. | Effect of Carbonic Maceration (CM) on the Vacuum Microwave Drying of Chinese Ginger (Zingiber officinale Roscoe) Slices: Drying Characteristic, Moisture Migration, Antioxidant Activity, and Microstructure | 10.1007/s11947-020-02504-y |
2020-09-01 | The present study was focused on the bioenergy potential of Madhuca longifolia (mahua, MH) seeds to produce renewable fuel via thermocatalytic conversion. The physicochemical characterization of MH seed confirmed its bioenergy potential. Three model-free models were used to predict the pyrolysis kinetics of MH. The thermodynamic and kinetic analysis showed that MH has complex reaction kinetics which depends on the reaction rate as well as reaction order. Mahua seed was pyrolyzed in a semi-batch cylindrical shaped reactor with (CuO, Al 2 O 3 , and NaOH) and without catalysts. The yield of pyrolytic liquid during thermal pyrolysis was 51.2 wt%, whereas the use of catalysts decreased the liquid yield slightly at various biomass to catalyst ratios. Further, characterization results revealed that the use of catalysts improved the properties of pyrolytic oil by reducing viscosity, oxygenated compounds and with increasing heating value and acidity. FTIR spectra of pyrolytic oil confirmed the existence of phenols, aromatics, water, and acids which was also supported by the 1 H NMR analysis. Further, GC-MS analysis confirmed reduction in oxygenated compounds and increase in alcohol. | Pyrolysis characteristics, fuel properties, and compositional study of Madhuca longifolia seeds over metal oxide catalysts | 10.1007/s13399-019-00469-3 |
2020-09-01 | This study aims to interpret the temperature and pressure behavior of an open-hole horizontal gas well (OHHGW) in a low-permeability gas reservoir in order to obtain the permeability and production profile of the OHHGW. First, the mathematical model, which is comprised of viscous dissipation, friction, the Joule–Thomson effect, and several other micro-thermal effects, was developed under a single-phase condition. Second, during the process of solving the numerical model, the drilling skin, heterogeneity, and non-Darcy effect were taken into consideration. In addition, the reservoir and wellbore models were coupled. Third, the testing temperature and pressure data were inverted using the Levenberg–Marquardt (LM) or Markov Chain simulated annealing algorithms, and the permeability and production profiles of the wellbore were obtained. The synthetic cases demonstrate the models’ ability to predict the temperature profile, and the results show the following: (a) The inversion results are in good agreement with the actual data, that is, the model can provide effective guidance for horizontal well development. (b) The wellbore temperature is lower than that of the reservoir boundary, so the micro-thermal effects for the horizontal gas well cannot be ignored during production. (c) As the gas production, the relative density of the gas, and the drilling skin factor increase, the wellbore temperature profile gradually decreases. The wellbore temperature increases with increasing horizontal permeability. (d) The trend of the temperature profile is contrary to the flow path of the wellbore fluid. (e) Reservoir heterogeneity has a significant influence on the temperature profile. | An Interpretation Method for a Gas Production Profile Based on the Temperature and Pressure Behavior of Low-Permeability Gas Reservoirs | 10.1007/s13369-020-04545-z |
2020-09-01 | The high-spectral-resolution detection of hard X-rays (E > 20 keV) is a challenging and nearly unexplored area in space astrophysics. Traditionally hard X-ray detectors present moderate spectral resolutions, although few tens of eV one could open new frontiers in the study of nuclear processes and high-temperature plasma dynamics in energetic processes. This can be achieved by using cryogenic microcalorimeters. Within a research activity aimed at developing arrays of neutron transmutation-doped germanium (NTD-Ge) microcalorimeters for the high-spectral-resolution detection (about 50 eV@60 keV) of hard X-rays (20 keV < E<100 keV), we developed an electroplating process to fabricate high-thickness (> 60 μm) bismuth absorber arrays. The adopted technological process and the study of related process parameters are discussed; preliminary results on produced arrays are given. | Fabrication of Bismuth Absorber Arrays for NTD-Ge Hard X-ray Microcalorimeters | 10.1007/s10909-020-02475-6 |
2020-09-01 | Nowadays, one of the most important global goals in medicine is to find ways to control cancer. Magnetic fluid hyperthermia is a promising method for cancer treatment due to its localized influence and low damage to healthy tissue. Ferrite nanoparticles are widely used in this cancer modality because of their low Curie temperature, biocompatibility, and production simplicity. In this work, (Mn (1− x ) Zn x )Fe 2 O 4 sol was obtained by hydrothermal synthesis from chlorides of zinc, manganese, and iron (III) at 180 °C for x = 0.1 and x = 0.2. The results of dynamic light scattering analysis have shown that the average hydrodynamic diameter of nanoparticles in the sol is about 70 nm. According to scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), the powdered nanoparticles are spherical with a high degree of crystallinity. X-ray powder diffraction analysis (XRD) has confirmed single-phase formation in samples. The magnetic properties measured have indicated that the nanoparticles have reached temperatures close to the range required for deactivation of cancer cells under the influence of a variable magnetic field. Manganese–zinc ferrite sol was synthesized by the hydrothermal method. Manganese–zinc ferrite nanoparticles were characterized by structural, morphological, and optical studies. Magnetic properties of manganese–zinc ferrite sol indicated that the nanoparticles obtained have relatively low saturation temperatures. Manganese–zinc ferrite nanoparticles are prospective agents for cancer treatment applications. | Synthesis of (Mn(1−x)Znx)Fe2O4 nanoparticles for magnetocaloric applications | 10.1007/s10971-020-05237-8 |
2020-09-01 | Abstract Amorphous InGaZnO (a-IGZO) TFTs become mainstream at the forefront of display backplanes and are actively expanding their area for next-generation optoelectronic devices such as flexible and transparent displays. For flexible displays, low temperature processed passivation technology is required to keep the reliability of the electrical properties in a-IGZO TFTs without damaging flexible plastic substrates. Here, we proposed a low-temperature passivation process using a dual-chamber system. A high-quality passivation layer composed of octadecyl-trichlorosilane was formed at 140 °C under vacuum on the back-channel of a-IGZO TFTs using the system. The thermally deposited self-assembled monolayers (SAMs) enable the formation of hydrophobic surfaces on a-IGZO TFTs, leading to the protection of the back-channel against water and oxygen efficiently. As a result, the electrical characteristics such as the threshold voltage shift, hysteresis, field-effect mobility, and negative bias stress of the SAM treated TFTs were significantly improved compared to those of the control TFTs. Graphic Abstract | Improving Electrical Stability of a-InGaZnO Thin-Film Transistors with Thermally Deposited Self-Assembled Monolayers | 10.1007/s13391-020-00232-1 |
2020-09-01 | Large quantities of catalysts after their useful life are discarded as waste material from fertilizer industry. Disposal of spent catalyst is a problem as it falls under the category of hazardous industrial waste due to its heavy metals concentration. This investigation applied a novel approach to extract copper from spent low-temperature shift catalyst (CuO–ZnO–Al 2 O 3 ) using chelation process. Ethylenediaminetetraacetic acid (EDTA) was used as the chelating agent. Optimum parameters to extract 95% copper were found as: EDTA concentration 0.5 M, reaction temperature 100 °C, solid-to-liquid ratio 1:25 (g/ml), particle size 120 µm and reaction time 4 h. A kinetic analysis of the experimental data was done by shrinking core model which revealed the rate-controlling step of the leaching process as product layer diffusion. The activation energy calculated was 10.58 kJ/mol which supports leaching process to be the product layer diffusion controlled. The process adopted is eco-friendly as the EDTA was recovered after the extraction of copper from the spent catalyst and reused again. The recycled EDTA obtained after the extraction was characterized by NMR and SEM. The activity of the recycled EDTA was found to be consistent with the fresh EDTA. | A Greener Approach to Extract Copper from Fertilizer Industry Spent Catalyst | 10.1007/s13369-020-04652-x |
2020-09-01 | Abstract Changes in the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) for the plants Nicotiana tabacum L. and Secale cereale L. during low-temperature hardening have been investigated. It was determined that a transient increase in the content of MDA occurs in tobacco plants at the beginning of the hardening period with subsequent activation of SOD, APX, and CAT. Unlike tobacco, winter rye has an MDA content and activity of SOD, APX, and CAT throughout the hardening period that remains at the level of unhardened plants. In tobacco cells, the majority of SOD activity was detected in chloroplasts (90%), while other cellular structures accounted for only 10% of the total activity identified in PAGE. In winter rye cells, SOD activity was distributed evenly between chloroplasts and other cellular compartments (46% in chloroplasts and 54% outside of chloroplasts). The distribution of APX and CAT activity in tobacco and winter rye cells was identical: all APX was concentrated in chloroplasts, while all catalase activity was manifested outside of chloroplasts. It is concluded that tobacco and winter rye plants showed different antioxidant defense strategies under conditions of low hardening temperatures. Tobacco plants provided protection against oxidative damage during low-temperature hardening by increasing activity of SOD, APX, and CAT. Winter rye plants were able to avoid the development of oxidative stress during hardening due to uniform distribution of SOD activity in cells, maintaining the constitutive activity of SOD, APX, and CAT, and, probably, due to the accumulation of nonenzymatic antioxidants. | Change of Antioxidant Enzyme Activity during Low-Temperature Hardening of Nicotiana tabacum L. and Secale cereale L. | 10.1134/S1021443720050118 |
2020-09-01 | Museums, historical buildings mainly located in urban centers, may be seriously affected by pollution and other critical urban atmospheric conditions. In addition to museums, there are many other different cultural heritage indoor environments each having different characteristics, mainly depending on the type of preserved materials that are sensitive to pollution and urban conditions. In this contribution we report an investigation of the indoor air quality and some considerations about the conservation of historical artifacts located inside the Historical Museum of Bersaglieri in Rome. Specifically, we show the feasibility in the exhibition rooms of a microclimatic characterization to evaluate the air quality, a critical issue for many of the artifacts exposed in confined spaces. The work we carried out is the monitoring of the behavior of temperature and relative humidity and the presence of airborne pollutants inside the museum halls. Taking into account the regulations in force that control and protect the Italian museums, these measurements have been carried out by using a customized and flexible system based on low-cost multi-parameter sensors allowing the monitoring of several environmental parameters. In spite of the limitation of this preliminary test study, on the basis of the results and according to the different preserved materials, a set of indications, criteria and tools have been provided to the museum managers to implement an effective "conservative strategy". | Micro-climatic investigation and particulate detection in indoor environments: the case of the historical museum of Bersaglieri in Rome | 10.1007/s12210-020-00935-5 |
2020-09-01 | Abstract A combination of large void volume and rich microporous structure enables expanded graphite (EG) to possess excellent adsorption properties. Furthermore, it is discovered to be hydrophilic with the capability of adsorbing NO x . The ball milling method was applied in preparation of the MnO x /TiO 2 modified by expanded graphite catalysts with the aim to improve SCR activity and resistance to H 2 O and SO 2 . An optimal SCR performance was obtained over the catalysts with 5 wt% EG doping. Subsequently, an investigation was conducted by XPS, NH 3 -TPD, H 2 -TPR into the understanding of the SCR catalytic performance of MnO x /TiO 2 at low-temperature. As revealed by the investigation results, the catalyst modified by EG had more Mn 4+ species and could absorb more oxygen, which allowed it to present more surface acid sites that could boost SCR activity. In addition, it was discovered that the introduction of EG could facilitate the improvement on the resistance to H 2 O and SO 2 . Graphic Abstract Expanded graphite (EG) has used to improve the SCR activity and resistance to H 2 O and SO 2 over the MnO x /TiO 2 . The catalyst with the addition of 5% EG was found to have more surface acid sites, surface adsorbed oxygen and Mn 4+ species. | Enhancement of Low-Temperature NH3-SCR Catalytic Activity and H2O Resistance Ability Over MnOx/TiO2 Catalyst by Expanded Graphite | 10.1007/s10562-020-03170-7 |
2020-09-01 | Abstract —The eight-year dynamics of the quality of motherwort ( Leonurus quinquelobatus Gilib.) seed progeny growing for more than 60 years under chronic radiation in the East-Ural Radioactive Trace (EURT) zone, in comparison with background cenopopulations, has been studied. The absorbed dose rates of the parent plants in the EURT area exceed the background level by 1–3 orders of magnitude. The unique dependence between the radiation dose of mother plants and the seed progeny quality was not found. A key role in the formation of Leonurus quinquelobatus seeds belongs to weather factors, as well as the combined effect of weather conditions and chronic irradiation. All the studied characteristics of Leonurus quinquelobatus seed progeny quality from the EURT zone positively correlated with the effective temperature sum in April, i.e., with thermal conditions at the beginning of plant vegetation. The main meteorological factors that affected the physiological response (viability, mutability, and radiosensitivity) of Leonurus quinquelobatus of the background and impact zones were Selyaninov’s index in April of the current season and the amount of precipitation in November of last year. The viability of seed progeny had a negative correlation with Selyaninov’s index, whether the mutability of seed progeny had a positive correlation with Selyaninov’s index for background and impact samples. The physiological response to weather conditions, assessed by the seed radioresistance, was positive in the background samples and negative in the impact samples. The dependencies between the total precipitation in November of last year and the quality of seeds in the background samples were positive, and these dependences were negative in the impact samples. | Interannual Quality Variability in Motherwort (Leonurus quinquelobatus) Seed Progeny under Chronic Radiation Exposure | 10.1134/S1067413620050033 |
2020-09-01 | Abstract Two series of comparative experiments are carried out to select the most effective version of pressure oxidation technology (POT) for processing a pyrrhotine-containing charge (PCC) consisting of a mixture of ELNPP TCP and NPC NCP (enriched low-nickel pyrrhotine product and nickel-pyrrhotine concentrate). In the first version (basic), a standard oxidizing agent (oxygen) is used for pressure oxidation leaching (POL); in the second version, iron(III) sulfate is used. The use of iron(III) sulfate in comparison with oxygen makes it possible to significantly increase all the main indicators of the hydrometallurgical beneficiation of PCC. The substitution of iron(III) sulfate for oxygen in the POL operation after optimizing the operation parameters of the “head” POT operations is shown to achieve a high quality of the autoclave sulfide concentrate (ASC; 13–14% Ni) and the completeness of extraction of valuable components into it, namely, 96–97% nickel and 93–95% PGMs. An important competitive advantage of POL processes using iron(III) sulfate is that the formation of a bulky precipitate of iron hydroxides is almost completely excluded during the oxidation of pyrrhotine. In the version of “oxygen” leaching of PCC, it is the formation of this precipitate that causes a high level of the PGM losses with waste technological tailings technology and limits the possibility of improving the quality of ASC. A schematic diagram of POT is proposed for the POL-based hydrometallurgical beneficiation of PCC (ELNPP TCF, NPC NCP, SPM TCF, etc.) using iron(III) sulfate. This scheme can be implemented on the basis of the existing fleet of equipment for the hydrometallurgical production of the Nadezhda metallurgical plant at the minimum capital costs | Substantiation of a Combined Technology for the Hydrometallurgical Beneficiation of a Pyrrhotine-Containing Charge Based on Pressure Oxidation Leaching Using Ferric Sulfate as a Pyrrhotine Oxidizer | 10.1134/S003602952009013X |
2020-09-01 | Abstract M7 block of Santanghu oilfield is an abnormal low temperature tight oil reservoir. The effective development is very difficult. In this paper, we develop a new composite viscosity reducer called CSY-1. The synergistic effect of these agents provides the reducer with both dispersion and emulsification capacities. Based on orthogonal experiment and cost evaluation, the optimum formula of CSY-1 is 0.5% OP-10, 1.8% SDBS, 0.1% Tween 80, and 1% NaOH (or Na 2 CO 3 ). The rheology property of heavy oil changed fundamentally before and after the addition of CSY-1. Oil-in-water emulsion with very low viscosity can be obtained and the viscosity reduction rate can be over 99%. Simulation results showed that the oil production of a single well can be increased from the current 3.74 t/d to 8.12 t/d with the application of this reducer. | A New Composite Viscosity Reducer for Abnormal Low Temperature Extra-Heavy Oil Reservoir with High Acid Value | 10.1134/S0965544120090054 |
2020-09-01 | Abstract Composites Fe m O n –Fe 3 – x Ti x O 4 have been synthesized using the sol–gel method and hydrothermal treatment. The conditions chosen for the synthesis favor the formation of composites containing titanomagnetite in a relatively low concentration. The theoretical analysis of the magnetic properties of the composites is performed based on the hysteresis curves and the temperature dependences of the remanent magnetization using the cluster model of magnetostatically interacting two-phase particles. | Magnetic States of Two-Phase Synthesized FemOn–Fe3 – xTixO4 Particles: Experimental and Theoretical Analysis | 10.1134/S1063783420090139 |
2020-09-01 | The computation methods of the thermodynamic properties are used for theoretical studies of multicomponent refrigerant blends (MRBs) for low-temperature throttling refrigeration units, providing cryostatting modes for cooled objects in the temperature range of –90 – –160 °С. The article presents the comparative analysis of the state equations for calculating thermodynamic properties of multicomponent refrigerant mixtures. Quantitative and qualitative differences in the results of calculations in the lowtemperature region are determined. | Comparative Analysis of Equations of State for Calculating the Thermodynamic Properties of a Vapor-Liquid Multicomponent Refrigerant Blend Comprising the Working Fluid of a Low-Temperature Throttling Refrigeration Unit | 10.1007/s10556-020-00786-9 |
2020-09-01 | Abstract The reaction of KBiO 3–δ with Ba 2+ ions at a Ba : Bi ratio of 0.5‒1.6 (mol.) in a 10 M. KOH solution under reflux (~140°C) has furnished oxides, which composition and structure have been studied by X-ray diffraction, energy dispersive X-Ray, and chemical analysis. Pseudo cubic ( а = 4.271‒4.285 Å) perovskite-like phases of barium‒bismuth(III,V)‒potassium oxides with insignificant impurity of sodium have been formed in the KBiO 3–δ ‒Ba 2+ ‒OH – ‒H 2 O system during 1 h. The products have been characterized by an average oxidation state of bismuth – Bi = 4.36‒4.59. Barium content in the resulting oxides has increased with an increase in its concentration in the charge. According to the Ba–Bi ratio, the resulting phases can be classified as non-superconducting oxides of homologous series М x Ba m Bi m + n O y ( x < n ), М x Ba m Bi m + n O y , and (М, Ba) m+n Bi m O y ( m = 1, 2, ...; n = 0, 1, 2, ...), M = K, Na. | Low-Temperature Synthesis of K–Ba–Bi–O Oxides in KOH
Solution | 10.1134/S1070363220090157 |
2020-09-01 | We have developed a test setup to measure frequency up-conversion gain in superconductor–insulator–superconductor (SIS) junctions at W band (75–110 GHz). A conventional SIS mixer with Nb/AlO x /Nb tunnel junctions was used as a frequency up-converter. An up-converted signal is measured by a room-temperature down-converter system. We observed distinct intermediate frequency responses to signal inputs from a continuous microwave source. The measured single-sideband up-conversion gain in SIS junctions was clearly positive (> 0 dB) with input frequency less than 2 GHz, which was well-calibrated by using an input from the continuous-wave source. | Observation of Frequency Up-Conversion Gain in SIS Junctions at W Band | 10.1007/s10909-020-02470-x |
2020-09-01 | Low-alloy steel bolts are used in applications where high strength is needed, although they presented low corrosion resistance, limiting their application in harsh environments. Ni-P coatings could be an alternative to protect low-alloy steel bolts against corrosion. However, Ni-P coatings must be submitted to an interdiffusion post-heat treatment, which provokes severe microstructural changes in the steel substrate, lowering its strength. This research aims to investigate two new thermal routes to obtain Ni-P coatings on low-alloy steel bolts, aiming to preserve the steel substrate's resistance and deformation properties, addressing the ASTM A320/L7 requirements. The first route proposed consists of obtaining the Ni-P coating on an austempered steel substrate, instead of a quenched/tempered one. This approach resulted in less microstructural changes during the post-heat treatment, although poor impact properties were achieved. The second thermal route consists of Ni-P coating on a quenched substrate, followed by a single-step post-heat treatment aiming to temper the substrate and promote the coatings' interdiffusion at the same time. The single-step post-heat treatment performed at 600 °C for 4 h resulted in appropriated mechanical properties while assuring the creation of a proper coating/steel interdiffusion layer, showing the feasibility to use Ni-P coatings in low-alloy steel to be used in harsh environments. | Strength and Deformation Properties of Low-Alloy Steel Bolts with Electroless Ni-P Coating: An Investigation of Two Thermal Routes | 10.1007/s11665-020-05066-4 |
2020-09-01 | The pyrolysis of low-rank coal is considered as the optimal method of realizing clean and efficient production of blue coke, tar, and gas. The experiments of low-rank coal microwave pyrolysis under CO 2 , CH 4 , H 2 , and circulating gas (CG) are studied in a custom-designed microwave oven to clearly clarify the effects of reaction atmospheres on pyrolysis temperature, products yields, and spectroscopic characteristics of pyrolysis products by the analysis techniques of FT-IR and GC-MS. The results show that among four pyrolysis atmospheres, the temperature-rise rate and final pyrolysis temperature under H 2 atmosphere are both highest, taking only 5.6 min to arrive at 750°C, and the final temperature is greater than 950°C. The liquid yields under CO 2 , CH 4 , H 2 , and CG atmospheres are 21.8, 24.4, 28.2, and 26.8 wt.%, respectively. The contents of –OH, aromatic ring C=C double bond, and –C=O in the solid product under CH 4 atmosphere are highest, possibly because of the thermal polycondensation and the secondary degassing of the solid product. The hydrogenation of H free radicals dissociated from “rich hydrogen” gas results in an improvement in the alkane content and a decrease in the aromatic hydrocarbon content in tar, which is confirmed by the change in oxygen content in the solid product. The hydrogenation technique of circulating coal gas on low-rank coal microwave pyrolysis is economical, energy-efficient, and feasible, which is helpful in the development of coal processing technologies. | Spectroscopic Analysis of Products from Low-Rank Coal Microwave Pyrolysis: Effect of Reaction Atmosphere | 10.1007/s10812-020-01064-5 |
2020-09-01 | Coastal engineering is an important measure in coping with coastal risks. With global warming and sea level rising, the sustainable adaptation of the low-lying areas becomes urgent. An in-depth understanding of the relationship between coastal engineering and environmental changes can help improve the adaptation capability for climate change. Here, we use historical documents and synthesis approach to examine coastal engineering evolution on the Jiangsu coast, the largest lowland area along China’s coastlines, and explore its response to local sea level and land use changes. The results show that coastal engineering here experienced a long-term period centered on sea-dike construction, with a shift from primary function of storm surge prevention since the eleventh century, towards a green coastal engineering approach in recent years. On the century scale, there was a close connection between local sea level change and coastal engineering change, while on the ten-year scale, population dynamics and land use changes were the key driving factors. Since the future climate and sea level change magnitude will be beyond what has been observed on the Jiangsu coast, it would be sensible to define a “critical time” that divides the near future and remote future. On such a basis, a strategic plan for the remote future may be formulated to prepare for the critical time when inevitable inundation occurs, and a second strategic plan may be adopted for the near future, to buy time for the coastal communities to make necessary preparations and at the same time to continue to use the resources. For the “near future,” a green coastal engineering approach (in combination with the experiences gained from the Jiangsu coast) should be developed to provide a low cost, high efficiency technique for coastal defense schemes. The thoughts outlined above may be applicable also to a number of low-lying coastal regions of developing countries. | Coastal engineering evolution in low-lying areas and adaptation practice since the eleventh century, Jiangsu Province, China | 10.1007/s10584-020-02738-x |
2020-09-01 | Abstract In hot desert climates, the office buildings with high-performance glazing systems (HPGSs) provide better indoor thermal and visual comfort to the occupants due to the advanced coatings which prevent the undesired heat gain and daylight. However, these systems save energy in the use phase; it could consume more energy in the pre-use and post-use phases. Furthermore, the use of advanced materials may have negative impacts on the environment. Therefore, this paper selected the comparative life cycle assessment method as an environmental measuring tool to compare the energy consumption and the environmental impacts of three HPGSs with that of the conventional clear double-glazing system. The results show that the photovoltaic glazing system (PVGS) has the lowest energy consumption and the lowest environmental impacts, followed by the electrochromic glazing system (ECGS) and the low-E glazing system. In the use phase, both PVGS and ECGS achieved the highest energy savings, 87% and 25%, respectively. The use phase has a major contribution to the energy consumption and environmental impacts, while the pre-use and post-use phases have insignificant contributions in this study. The results could support decision-makers in choosing the most environmentally friendly HPGS for their projects. Graphic abstract | A comparative life cycle assessment of three high-performance glazing systems for office buildings in a hot desert climate zone | 10.1007/s10098-020-01891-2 |
2020-09-01 | Abstract The effect of MeV protons on the surface properties of a low-density polyethylene film was studied using EPR spectroscopy and thermomechanical spectrometry. The diblock semicrystalline structure of polyethylene was preserved upon proton irradiation; the molecular weight decreased, and the weight fraction of the crystalline modification increased. In the EPR spectrum of the irradiated polymer, allyl radicals were predominantly detected. At high proton fluences, the hyperfine structure disappeared from the EPR spectra, and they turned into a singlet with a line width of 4.1 or 3.5 mT as recorded at 23 and –196°C, respectively. | Influence of Accelerated Protons on the Molecular–Topological Structure of Polyethylene | 10.1134/S0018143920050021 |
2020-09-01 | Abstract The paper reviews studies of the Laboratory of Theoretical Physics of the Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences. Two research directions are discussed: transport properties of two-dimensional excitonic systems and electron transport in two-dimensional topological insulators. Particular attention is given to excitonic systems in the mode of Bose–Einstein condensate and to the theory of conductivity of two-dimensional topogical insulator with a thickness close to the critical one caused by developed network of edge states permeating the sample. | Transport Properties of Two-Dimensional Topological Insulators and Excitonic Condensates | 10.3103/S8756699020050027 |
2020-09-01 | An equiatomic MgAlSiCrFe high-entropy alloy was synthesized by mechanical alloying. The alloying behavior, phase evolution, phase composition and thermal stability of as-milled nanostructured powders of HEA were ascertained through X-ray diffraction and transmission electron microscopy, scanning electron microscopy and differential scanning calorimetry (DSC), respectively. The milling of elemental powders for 60 h led to the formation of HEA with a major BCC phase having lattice parameter of 0.2887 ± 0.005 nm very close to that of the α-Fe and a minor fraction of undissolved Si. The nanocrystalline HEA powder formed during milling has crystallite size of 19 ± 0.8 nm. The STEM–EDS mapping of these milled powders confirms the homogenous elemental distribution after 60 h of mechanical alloying. The DSC thermogram of 60 h milled HEA powder shows the thermal stability of milled powder up to ~ 400 °C. The exothermic heating events observed in the DSC thermogram correspond to phase transformation of MgAlSiCrFe HEA powder, and it may be correlated with the phases observed through the ex situ XRD of HEA powders annealed at different temperatures up to 700 °C. After annealing the 60 h milled powder, various phases along with parent BCC phase have evolved, i.e., B2 type Al–Fe phase, FCC phases (Al–Mg solid solution), Cr 5 Si 3 , Mg 2 Si, Al 13 Fe 4 . Further, the experimental findings were correlated with various thermodynamic parameters for understanding the phase evolution and stability. | Phase Evolution and Thermal Stability of Low-Density MgAlSiCrFe High-Entropy Alloy Processed Through Mechanical Alloying | 10.1007/s12666-020-02039-y |
2020-09-01 | Abstract Dinosaur footprints were found in Pliensbachian terrigenous rocks in the central North Caucasus. Tracks of different sizes (12‒35 cm) were identified at three levels of the Mizur Formation section. The sediments accumulated on the wide (15‒20 km) shelf of a paleobasin. The coastal land was covered with abundant vegetation. The warm and humid climate favored the development of weathering crusts, lake–bog systems, and peat accumulation. The seawater temperature ranged from 21 to 25°C. The accumulation of sediments on the shallow shelf and their distribution over the area were influenced by wave activity, currents, and tidal phenomena. At low tide, small dinosaurs visited the shelf zone in order to search for food in the form of benthic fauna, which was abundant in clayey–silty sediments. The simultaneous presence of significantly different–size animal tracks may indicate that large individuals preyed on smaller ones. The presence of dinosaur tracks at different levels of the upper Pliensbachian strata indicates that representatives of the terrestrial fauna periodically visited the paleoshelf during the Domerian. | Dinosaur Footprints in Terrigenous Sediments on the Early Jurassic Shelf of the Central North Caucasus: Sedimentological and Paleoecological Settings | 10.1134/S002449022005003X |
2020-09-01 | Abstract Optical infrared gas analyzers are developed for mixtures of vapors of liquefied natural gas and air. It is found that a network of them allows temperatures of −100 to +60°C to be measured along with volume concentrations of hydrocarbons С = 0.5–100 vol % with temporal responses of less than 1–2 s when analyzing methane–air emissions and clouds in the atmosphere with volumes of up to 10 7 m 3 and data transmitted to a remote server at rates of up to 10 km every 1 ms. It is shown that with large-scale pulsed emissions of liquefied natural gas into the atmosphere or spills of it onto dry ground or water, conditions are created for the long-term formation of flammable and explosive mixtures of air and hydrocarbons at concentrations C = 5–15 vol %. | Infrared Gas Analyzers for Monitoring Emissions of Flammable and Explosive Natural Gas into the Atmosphere | 10.1134/S0036024420090332 |
2020-09-01 | Phycobiliproteins (PBPs) are pigment proteins that comprise phycobilisomes (PBS), major light-harvesting antenna complexes of cyanobacteria and red algae. PBS core substructures are made up of allophycocyanins (APs), a subfamily of PBPs. Five paralogous AP subunits are encoded by the Far-Red Light Photoacclimation (FaRLiP) gene cluster, which is transcriptionally activated in cells grown in far-red light (FRL; λ = 700 to 800 nm). FaRLiP gene expression enables some terrestrial cyanobacteria to remodel their PBS and photosystems and perform oxygenic photosynthesis in far-red light (FRL). Paralogous AP genes encoding a putative, FRL-absorbing AP (FRL-AP) are also found in an operon associated with improved low-light growth (LL; < 50 μmol photons m –2 s –1 ) in some thermophilic Synechococcus spp., a phenomenon termed low-light photoacclimation (LoLiP). In this study, apc genes from FaRLiP and LoLiP gene clusters were heterologously expressed individually and in combinations in Escherichia coli . The resulting novel FRL-APs were characterized and identified as major contributors to the FRL absorbance observed in whole cells after FaRLiP and potentially LoLiP. Post-translational modifications of native FRL-APs from FaRLiP cyanobacterium, Leptolyngbya sp. strain JSC-1, were analyzed by mass spectrometry. The PBP complexes made in two FaRLiP organisms were compared, revealing strain-specific diversity in the FaRLiP responses of cyanobacteria. Through analyses of native and recombinant proteins, we improved our understanding of how different cyanobacterial strains utilize specialized APs to acclimate to FRL and LL. We discuss some insights into structural changes that may allow these APs to absorb longer light wavelengths than their visible-light-absorbing paralogs. | Characterization of cyanobacterial allophycocyanins absorbing far-red light | 10.1007/s11120-020-00775-2 |
2020-09-01 | Ozone in the upper troposphere–lower stratosphere (UTLS) is primarily regulated by tropospheric dynamics. Understanding mechanisms driving ozone variability at the UTLS is crucial to evaluate the transport of mass to and from the lower stratosphere. The El Niño-Southern Oscillation (ENSO) is the primary coupled mode acting on interannual timescales modulating tropospheric circulation worldwide. ENSO teleconnections can depend on the phases of the Pacific Decadal Oscillation (PDO) and on the characteristics of the warming over central and eastern tropical Pacific. This study investigates the role of ENSO on UTLS ozone variability with focus on South America and examines patterns of teleconnections in the two recent warm (1980–1997) and cool (1998–2012) PDO phases. The dominant mode of ozone variability is identified by applying a principal component analysis (PCA) to modern-era retrospective analysis for research and applications, Version 2 (MERRA-2) ozone data from September–November (SON). SON is the season with the largest UTLS ozone variance over South America. The first mode resembles a Rossby wave train across South America with spatial patterns dependent on PDO phase. We show that the ENSO teleconnections and respective influences on SON UTLS ozone are stronger during the cool PDO when ENSO and PDO are mostly in phase. Additionally, the strength of the ENSO teleconnection appears to depend on patterns of SST anomalies over tropical Pacific. The decadal variability in the ENSO-PDO relationships and teleconnections with the Southern Hemisphere resulted in a shift in upper tropospheric circulation in tropical and subtropical regions of South America. | The combined influence of ENSO and PDO on the spring UTLS ozone variability in South America | 10.1007/s00382-020-05340-0 |
2020-09-01 | The corrosion behavior of two types of low-carbon steel (denoted steel A and steel B) in H 2 S/CO 2 was investigated through immersion tests, and the effect of Ti microalloying on the corrosion mechanism was analyzed. The microstructures, corrosion kinetics, corrosion surface morphologies, corrosion phases, cross-sectional morphologies and elemental distributions of the materials were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron backscatter diffraction (EBSD), energy-dispersive spectroscopy (EDS), x-ray diffraction (XRD) and electron probe microanalysis (EPMA). The results showed that the corrosion rate of steel B with Ti microalloying was lower than that of steel A; the amount and formation rate of corrosion products in these two materials were different. As the immersion time increased, the corrosion products changed from iron-rich mackinawite to sulfur-rich pyrrhotite. In the early stage of corrosion, the corrosion products were primarily mackinawite, which controlled the corrosion phase through the entire process. After 384 h of immersion, pyrrhotite was observed, which can effectively protect the steel substrate, providing excellent corrosion resistance. The corrosion products in steel B with Ti microalloying were more compact than those in steel A. Moreover, Ti enrichment in the oxide film was observed in steel B, which can further improve its corrosion resistance. The results from this study can provide an important reference for the oil and gas industry. | Effect of Ti Microalloying on the Corrosion Behavior of Low-Carbon Steel in H2S/CO2 Environment | 10.1007/s11665-020-05077-1 |
2020-09-01 | Eco-environmental changes during interglacials with an astronomical background similar to that of the Holocene are potentially helpful for understanding the future climatic evolution. Marine oxygen isotope stage (MIS) 19 is similar to the Holocene in astronomical background, both being characterized by a low eccentricity of the Earth’s orbit. However, MIS 19 has attracted research attention only recently and therefore less is known about eco-environmental changes during this interval, especially based on terrestrial records. In the Chinese Loess Plateau (CLP), the S7 paleosol can provide valuable terrestrial paleoclimatic and paleoenvironmental record for MIS 19. Here, high-resolution terrestrial snail records from the L8-L7 strata of the Huining, Xifeng and Luochuan sequences in the CLP were analyzed in order to characterize spatio-temporal changes in climate and eco-environment during MIS 20–18. The results show that in all three sections the late part of MIS 20 was dominated by abundant cold-aridiphilous mollusc species, indicating that cold and dry climatic conditions prevailed across the entire CLP, under the strong influence of the winter monsoon. The mollusc fauna of MIS 19 were dominated by warmth-loving and thermohumidiphilous species that enable the definition of two climatic stages. The early part of MIS 19 (∼790–778 ka) was marked by warm and humid conditions, as evidenced by high abundances of warmth-loving and thermo-humidiphilous species. This interval was slightly warmer than today and it lasted for ∼12 kyr. The climate of the later part of MIS 19 (∼778–761 ka) was more moderate, and increased proportions of cold-aridiphilous and warmth-loving species were recorded. The warmth of this period was similar to that of today, but the climatic fluctuations were stronger. During the early part of MIS 18 (∼761–745 ka), the Xifeng and Luochuan sections in the eastern CLP still maintained high abundances of warmth-loving and thermo-humidiphilous species, indicating that the moderate climatic conditions during late MIS 19 continued during early MIS 18, lasting for another ∼15 kyr, and that the influence of the summer monsoon remained strong in the eastern CLP during early MIS 18. However, in the western CLP, cold-aridiphilous species in the Huining section became dominant during early MIS 18, reflecting the prevalence of a cold and dry glacial climate, with the strong influence of the winter monsoon. These findings indicate that a steeper climatic gradient and a pronounced regional environmental difference existed between the eastern and western CLP during the early part of MIS 18. Comparison of our mollusc results with the variation of Earth orbital parameters suggested that climate changes in the CLP during MIS 20-18 were likely controlled mainly by insolation changes forced by the configuration of Earth orbital parameters. The unique orbital configuration during the low eccentricity interglacial-to-glacial transition could have strengthened the East Asian summer monsoon which favored the amelioration of the eco-environment in the CLP, especially in the eastern CLP where the summer monsoon exerted a strong influence. Thus we speculate that, under natural climatic conditions, the climate of the CLP may remain in a warm, humid state for another 30 kyr, although climatic instability and the seasonal differences between winter and summer could strengthen. | Eco-environmental changes in the Chinese Loess Plateau during low-eccentricity interglacial Marine Isotope Stage 19 | 10.1007/s11430-020-9628-5 |
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