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2023-03-01 | Evidence of the IoT is expanding the number of connected devices, including UAVs. UAVs overcome the flaws in the physical IoT infrastructure already in place. Low-altitude views are expected to be dominant swiftly in urban areas. In a short period of time, they are able to cover a large area and distribute goods and information around the globe. Additionally, how to provide a safe and secure UAV operation in high-level traffic circumstances is also a topic of investigation. When operating an UAV in a limited area, the IoLoUA system is used to maintain order. Additionally, it aids with node exploration. Basic principles that can be used to create new structural designs are analysed for both networks (IoLoUA). There has been an explanation of the IoLoUA strategy’s approach to implementation so far. Among the issues covered in this article are UAV-generated IoT data collection and delivery, security threats, and typical workflow approaches. This work presents a theoretical model of future design evolution. | Internet of Low-Altitude UAVs (IoLoUA): a methodical modeling on integration of Internet of “Things” with “UAV” possibilities and tests | 10.1007/s10462-022-10225-1 |
2023-03-01 | Crystals of Sodium Laurate, Lauric Acid (NaLLA) were obtained and the structure was determined by single-crystal X-ray diffraction. The new crystal form is monoclinic of space group P2 1 /c. The asymmetric unit contains two independent laurate molecules whose carboxylic/carboxylate groups are linked by a low barrier O-H…O hydrogen bond. Two lauric/laurate molecules are in a head-to-head configuration and the elongated hydrophobic chains are parallel to the long b axis. The carboxylic hydrogen atom was found to be disordered, bound on each of the two carboxylate groups in an unsymmetrical way. The non-symmetrical character of the hydrogen bond is related to the presence of two independent fatty acid molecules in the asymmetric unit and is in accordance with the different lengths of the four C-O bonds present in the molecular structure. The crystal structure was analyzed in terms of interactions on the Hirshfeld surface. The packing is stabilized by hydrogen bonds and O…Na ionic interactions in the hydrophilic layer and by C-H…H-C contacts in the hydrophobic layers which are the most enriched major contacts. | Case of Charge-Assisted Hydrogen Bonding in the Crystal Structure of Sodium Laurate, Lauric Acid | 10.1007/s10870-022-00946-0 |
2023-03-01 | Low-phosphorus stress significantly impacts the development of maize kernels. In this study, the phosphor efficient maize genotype 082 and phosphor deficient maize genotype Ye107, were used to construct an F 2:3 population. QTL mapping was then employed to determine the genetic basis of differences in the maize kernel traits of the two parents in a low-phosphorus environment. This analysis revealed several major QTL that control environmental impacts on kernel length, width, thickness, and weight. These QTL were detected in all three environments and were distributed on five genome segments of chromosomes 3, 5, 6, and 9, and some new kernel-trait QTL were also detected (eg: Qkwid6 , Qkthi3 , Qkwei9 , and Qklen3-1 ). These environmentally insensitive QTL can be stably expressed in low phosphorus environments, indicating that they can lay a foundation for the breeding of high phosphorus utilization efficiency germplasm. | QTL mapping of maize (Zea mays L.) kernel traits under low-phosphorus stress | 10.1007/s12298-023-01300-0 |
2023-03-01 | Objective The current study aimed to estimate prevalence of malaria infection, especially sub-patent infection, in pregnant women residing in high malaria-endemic, hard-to-reach pockets of the Indian state of Odisha; and also measure its impact on birth-weight of their new-borns. Method A time-to-event analysis of prospective longitudinal follow-up study nested within a cross-sectional survey of people residing in high malaria-endemic six districts of Odisha was conducted during July–November 2019. Malaria status in pregnant mothers was categorized as malaria free; sub-patent, and patent. Hazards Ratio (HR) of low birth-weight (LBW; birth-weight < 2500 gms) was estimated in these three categories ( n = 308) adjusted for residence (block), gravida, caste, age and gestational age at testing. Results 50.3% pregnant women had sub-patent malaria infection, 3.9% had patent infection. In fully adjusted model, hazards ratio of LBW was 3.76 (95% CI 1.12, 12.64, p = 0.032) in pregnant women with patent infection and 1.82 (95% CI 0.87, 3.81, p = 0.109) in women with sub-patent infection when compared to no malaria group. Conclusion The study showed that half of the pregnant women in high-endemic pockets had sub-patent infection which posed deleterious influence on birth-weight of their new-borns. The study thereby flags the prevalence of sub-patent infection as a public health concern, because sub-patent infection in pregnant mothers may persist as a “silent” reservoir, with the potential to derail the malaria control program, especially when the country plans malaria elimination by 2030. | Impact of Sub-patent Malaria During Pregnancy on Birth-Weight in Odisha, India: Time-to-Event Analysis of Prospective Longitudinal Follow-Up of a Survey | 10.1007/s44197-022-00082-0 |
2023-03-01 | Decreased light conditions due to cloud cover and smog pollution severely limit crop cultivation and production. Reduced light interception coupled with irregular rainfall caused damage to major crops’ yield at their critical growth stages, especially at the post-silking stage in maize ( Zea mays L.). This study was conducted in underground soil columns containing a moveable shed (to apply shade and avoid rainfall) to investigate the combined effect of drought and shading stress at the post-silking stage of maize. Plants were exposed to five shading treatments (a control without shading (SD0), shading for 3 (SD3), 6 (SD6), 9 (SD9), and 12 days (SD12)) and four drought levels (100, 75, 50, and 25% of irrigation) after silking in maize. A split-plot design was used. The combined stresses caused oxidative damage to maize leaves, which caused a significant reduction in the photosynthetic efficacy, grain yield, and grain quality. The combination of SD12 and 25% irrigation caused a 24% reduction in photosynthetic activity and grain yield compared with the respective control. Under interactive drought and shading conditions, SD12 combined with 25, 50, and 75% irrigation caused an upsurge in grain protein by 3.94, 8.06, and 6.70%, respectively. The combined drought and shading stress during the post-silking stage in maize caused a significant reduction in rain yield by altering antioxidant potential and photosynthetic efficiency. An increase in antioxidant defense was observed under combined stresses; however, this increase was insufficient to combat the oxidative damage caused by stress. | Physiological Mechanisms of Grain Yield Loss Under Combined Drought and Shading Stress at the Post-silking Stage in Maize | 10.1007/s42729-022-01108-z |
2023-03-01 | The Upper Cretaceous Ilam Formation in southwest Iran was studied in order to provide a better understanding of the palaeoenvironments that lead to the deposition of heterogeneous carbonate rocks. This formation is an important hydrocarbon reservoir of the Bangestan Group in the Zagros Basin and the Abadan Plain. The Ilam Formation is comprised mainly of carbonate rocks and was studied from three subsurface sections (100, 74, and 100 m thick). Petrographic investigation reveals that the Ilam Formation consists of 12 microfacies and a shale petrofacies that were deposited in lagoonal, shoal, and open marine facies belts of a carbonate ramp. Two third–order depositional sequences are recognised. Comparison of Ni/Co reveals that the limestones of the Ilam Formation formed under oxic to anoxic conditions. The main diagenetic features of the Ilam Formation include compaction, dissolution, dolomitization and cementation that occurred in marine, meteoric and burial diagenetic environments. We document for the first time the relationship between facies and geochemistry in the carbonate rocks of the Ilam Formation. These findings provide a more comprehensive understanding of the palaeoenvironments that lead to the deposition of heterogeneous carbonate rocks and their relationship with geochemistry and reservoir characteristics. | Variation of geochemical data and sedimentary characteristics in the Upper Cretaceous Ilam Formation, a case study from southwest Iran | 10.1007/s12549-022-00532-4 |
2023-03-01 | The rhizosphere microbiome plays a vital role in crop growth and adaptation. However, the effects of rice genotype, nitrogen (N) fertilization, and their interactions on the rhizosphere bacterial communities in low fertility soil remain poorly understood. In this study, a two-factor field experiment was performed in newly reclaimed mudflat paddies characterized by poor fertility to analyze bacterial communities in the rhizosphere of Yongyou 2640 (japonica/indica hybrid rice, JIH) and Huaidao No.5 (japonica conventional rice, JC) under different N fertilizer rates. Results showed that genotype, followed by N fertilizer rate, was the primary factor affecting rhizobacteria diversity. Rhizobacteria diversity was higher in JIH than in JC and that of JIH and JC did not significantly change overall as N fertilizer rates but increased and decreased at N fertilizer rates of over 300 kg N ha −1 , respectively. The inconsistent response was probably attributed to the difference in the increase of ammonium and/or nitrate in the rhizosphere of JIH and JC. Genotype explained approximately 26% of the variation in rhizosphere bacterial communities. Rhizosphere bacterial communities with N fertilizer rates of over 300 kg N ha −1 were more dissimilar to those without N fertilization relative to those with N fertilizer rates of below 300 kg N ha −1 , which was mainly attributed to changes in the concentration of ammonium and/or nitrate. The relative abundances of some potential beneficial genera such as Salinimicrobium , Salegentibacter , Gillisia , and Anaerolinea in the rhizosphere of JC and Salegentibacter , Lysobacter , Nocardioides , and Pontibacter in the rhizosphere of JIH were increased under N fertilizer rates of less than 300 kg N ha −1 and positively correlated with rice yields, which indicate that changes in bacterial communities caused by N fertilization might be strongly associated with the improvement of rice yield. Overall, rhizosphere bacterial communities were more sensitive to genotype in newly reclaimed mudflat paddies and showed a consistent response to N fertilizer rates. | Responses of rhizosphere bacterial communities in newly reclaimed mudflat paddies to rice genotype and nitrogen fertilizer rate | 10.1007/s11356-022-25020-2 |
2023-03-01 | Genomic selection (GS) is poised to revolutionize eucalypt tree improvement by shortening breeding cycles and increasing selection intensities. This could be particularly valuable for alternative, non-mainstream Eucalyptus species that are still in the initial stages of breeding. Eucalyptus benthamii is important for its adaptation to frost-prone subtropical regions. In this work, we compared seven genomic prediction models, six Bayesian and one frequentist GBLUP (Genomic Best Linear Unbiased Prediction) with the conventional pedigree-based ABLUP approach. Models were evaluated for their ability to estimate heritabilities and predict wood quality traits (wood density, extractives, lignin, and carbohydrates content) and volume growth in 77 open-pollinated families of Eucalyptus benthamii . We also evaluated predictive abilities and heritabilities using variable numbers of SNP in the models. Heritabilities ranged from 0.09 (extractives content) using Bayesian Lasso (BL) to 0.55 (wood density) using ABLUP. Predictive abilities (PA) ranged from 0.12 (for volume using ABLUP) to 0.44 (for wood density using three Bayesian models). All seven genomic models performed similarly well and better than the pedigree model for all traits, except extractives content. Subsets of 5000–7000 SNPs yielded heritabilities and PAs nearly as large as using all 15,293 SNPs. However, a low-density SNP panel might not be economically and technically advantageous compared to the current high-density multi-species Eucalyptus EUCHIP60k. Our results support a positive outlook to implement GS to accelerate Eucalyptus benthamii breeding for adaptation to frost-prone regions. | Genomic prediction of growth and wood quality traits in Eucalyptus benthamii using different genomic models and variable SNP genotyping density | 10.1007/s11056-022-09924-y |
2023-03-01 | The paper presents the results of studies of argon-nitrogen plasma of a non-self-sustained low-pressure glow discharge with a hollow cathode by optical emission spectrometry. The plasma was generated in a mixture of Ar–N 2 gases with an argon percentage from 0 to 100% at a total pressure of 1 Pa. The discharge current and voltage were maintained constant and amounted to 18 A and 165 V, respectively. A significant increase in the amount of Ar + (up to 30%) at a nitrogen content of 10–25% was shown, which is associated with a shift in the reaction of charge exchange of nitrogen with argon towards the generation of argon ions. It was found that at a low partial pressure of nitrogen (≈10%), a sharp increase in the content of atomic nitrogen is observed which is probably due to the dissociation of nitrogen molecules upon collisions with an excited argon atom. | Influence of the Percentage of Argon in the Ar–N2 Gas Mixture on the Relative Number of Ar+, N2+, N, and N+ Particles in the Plasma of a Non-Self-Sustained Low-Pressure Glow Discharge With a Hollow Cathode | 10.1007/s11182-023-02844-0 |
2023-03-01 | These are the first and so far only records of a sailfin velifer fish from the Lower Oligocene of the Unterfeld (“Frauenweiler”) clay pit at Rauenberg (S Germany), and only the fourth fossil skeletal finds of this group worldwide. The new genus and species † Oechsleria unterfeldensis is described in detail, diagnosed, and compared to other fossil and extant representatives of the Veliferidae. It appears to be a comparatively small-sized fish, which differs from the other representatives of this family, apart from body proportions, by having a lower number of vertebrae and dorsal-fin rays, the absence of massive spines in the dorsal and anal fins, four anal-fin pterygiophores in front of the anteriormost haemal spine, and a different morphology and size of various skeletal elements. Amongst others, the following character states are of relevance: a supraoccipital that is laterally sculptured by strong surface ridges; a weak ascending process of the premaxilla that is shorter than in the other veliferid taxa; compound (fused) anteriormost dorsal- and anal-fin pterygiophores, together with spineless dorsal and anal fins with unornamented rays (no spinules), of which the majority are bilaterally paired and both halves are fused only proximally but separate and segmented distally; a short coracoid that does not reach the ventral body margin; a broad and anterodorsally directed pelvic bone that bears a well-developed postpelvic process, and probably also the presence of a short pointed neural spine (in contrast to a distally blunt one and/or a low crest) on the second preural centrum. All in all, the new fossil records remarkably increase the known biodiversity of the Veliferidae. They also expand the known palaeogeographic range of this family as far as to the Western Paratethys. With reference to the occurrence and life habits as deduced from the extant forms, they seem to be another Indo-Pacific (respectively Palaeo-Mediterranean, when referring to the fossil forms) element of the Grube Unterfeld fish fauna with a preference for deeper waters and affinities to temperate to tropical climates. | Oechsleria unterfeldensis, gen. et sp. nov., a sailfin velifer fish (Lampridiformes, Veliferidae) from the Oligocene of the Unterfeld (“Frauenweiler”) clay pit | 10.1007/s12542-022-00633-7 |
2023-03-01 | China has become the largest energy producer and consumer in the world. Its carbon emissions account for 80% of its total carbon emissions, while the carbon emissions caused by energy consumption in the power industry account for more than 50%. To ensure that the 2030 carbon-peak and 2060 carbon–neutral targets are achieved, it is imperative to carry out low-carbon energy transformation in the power industry. The paper compares and analyzes the technical level of six high-energy-consuming industries: power, steel, cement, aluminum smelting, petrochemical industry, and coal chemical industry in terms of low carbon. The results show that the structural adjustment of China’s high-energy-consuming industries has reached the upper limit, and the low-carbon transformation of power and energy has become inevitable. The carbon emissions of China’s six regional power grids are statistically analyzed. The background of the power generation proportion of China’s thermal power, hydropower, nuclear power, wind power, solar power and other different energy systems from 2018 to 2020 is analyzed, and the development trend is predicted. The low-carbon emission path of power energy is proposed. Based on the EnergyPLAN model, the power energy structure of carbon peaking in different scenarios from 2020 to 2030 is constructed, and the power energy system’s carbon dioxide emission reduction paths under different scenarios are obtained. The sustainability impact of different power generation combination scenarios is comprehensively evaluated using the multi-index evaluation method, and the optimal path of the power system to energy scenario is selected. The research conclusion provides a basis for the power sector’s renewable energy power generation path selection. | Low-carbon transformation planning of China’s power energy system under the goal of carbon neutrality | 10.1007/s11356-023-25279-z |
2023-03-01 | Purpose To analyze the level of growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) in follicle fluid (FF) and granulosa cells (GCs) derived from young patients with low prognosis for in vitro fertilization and embryo transfer (IVF-ET) treatment. Methods A prospective cohort study was carried out by enrolling 52 young patients with low prognosis according to the POSEIDON classification group 3 (low prognosis group) and 51 young patients with normal ovarian reserve (control group). The concentration of the GDF9 and BMP15 proteins in FF was determined by enzyme-linked immunosorbent assay. The mRNA level of the GDF9 and BMP15 in the GCs was measured by quantitative real-time PCR. Results The concentration of GDF9 (1026.72 ± 159.12 pg/mL vs. 1298.06 ± 185.41 pg/mL) and BMP15 (685.23 ± 143.91 pg/mL vs. 794.37 ± 81.79 pg/mL) in FF and the mRNA level of GDF9 and BMP15 in the GCs and the live birth rate per treatment cycle started (30.77% vs. 50.98%) and oocytes retrieved (4.25 ± 1.91 vs. 12.04 ± 4.24) were significantly lower, whereas the canceled cycle rate was significantly higher (9.62% vs. 0) in the low prognosis group compared with the control group ( P < 0.05). The expression of GDF9 and BMP15 in the ovary was positively correlated with live birth ( P < 0.05). Conclusion The expression of GDF9 and BMP15 in the ovary was decreased in young patients with low prognosis accompanied by a poorer outcome of IVF-ET treatment. Trial registration ChiCTR1800016107 (Chinese Clinical Trial Registry), May 11, 2018. ( http://www.chictr.org.cn/edit.aspx?pid=27216&htm=4 ). | Decreased GDF9 and BMP15 in follicle fluid and granulosa cells and outcomes of IVF-ET among young patients with low prognosis | 10.1007/s10815-023-02723-0 |
2023-03-01 | Nitrogen pollution in groundwater is an environmental issue of global concern. Identifying nitrogen pollution sources and determining migration and transformation processes are the major ways to prevent and control nitrogen pollution in the groundwater on a regional scale. In this study, groundwater in the lower Wei River was investigated by combining multi-isotope tracing techniques with the SIAR hybrid model (source resolution) to trace the nitrate sources and their contribution rate to nitrogen pollution in groundwater of different geomorphological units, considering types of geomorphology as the units. The multi-isotope tracing technique allows dynamic analysis of nitrate sources, and the combination of this technology can improve the accuracy of nitrogen source traceability. The results indicated that the pH of the water bodies in the study area ranged from 6.83 to 8.01, which is neutral and weakly alkaline. The nitrogen pollution was mainly due to nitrates. The significant factors affecting nitrogen migration in groundwater are the geomorphological type, the chemical characteristics of the groundwater, and the age of the groundwater. Nitrogen migration and transformation processes in the study area were dominated by nitrification, and sources of nitrate pollution were mainly animal manure and domestic sewage (32.6%), followed by atmospheric deposition (26.8%), soil nitrogen (20.9%), and chemical fertilizer (19.7%). The main sources of nitrate in groundwater from river flats, alluvial plains, and loess tableland were animal manure and domestic sewage (43.7%), animal manure and domestic sewage (59.1%), and atmospheric deposition (55.5%), respectively. The result is mainly related to the different structural characteristics of various geomorphic units and the intensity of human activities. This study can provide a theoretical basis for the relevant agencies to develop plans to combat groundwater pollution. Graphical Abstract | Identification of nitrogen pollution sources and transport transformation processes in groundwater of different landforms using C, H, N, and O isotope techniques: an example from the lower Weihe River | 10.1007/s11356-022-24337-2 |
2023-03-01 | The results of experimental studies of analogs of columnar red sprites are presented. As is known, the development of sprites is due to the formation of cylindrical streamers at an altitude of 50–100 km from sea level. The velocities of a plasma diffuse jet (PDJ) obtained in a laboratory, which is an analog of a sprite, were measured, and its emission spectra were recorded. Estimates are made of the magnitude of the reduced electric field strength in the PDJ at various distances from the electrodes initiating the discharge. It has been established that the shape and color of the PDJ, which are also cylindrical streamers, at air pressures of 0.2–1.5 Torr corresponds to the color and shape of columnar red sprites. It is shown that the change in the color of diffuse plasma jets is associated with an increase in the reduced electric field strength. | Cylindrical Streamers Formed in Air and Nitrogen at Low Pressures | 10.1007/s11182-023-02856-w |
2023-03-01 | Purpose To evaluate the effect of an anti-inflammatory compared to a low-calorie diet on the physical and mental health of patients with knee OA. Methods In this randomized parallel clinical trial, participants were selected among overweight and obese women aged 40 years or older with mild to moderate OA. Sixty women with a ratio of 1:1 were randomly assigned to receive either low-calorie or anti-inflammatory accompanied by a low-calorie diet for two months. The dietary intake and weight of participants were measured. Study variables were assessed using the Western Ontario and McMaster Index (WOMAC), visual analog pain scale (VAS), Beck Depression Inventory (BDI-II), Beck Anxiety Inventory (BAI-I), and the Short Form 36 Health Survey Questionnaire (SF-36) to indicate the quality of life (QoL). Results There was no statistically significant difference between the two groups in demographic and baseline variables except for the emotional well-being subscale of QoL. There was significant difference in anti-inflammatory compared to low-calorie diet in terms of weight (MD (95% CI): − 4.02 kg (− 6.77 to − 1.28); p = 0.005), VAS (MD (95% CI): − 0.97 (− 1.53 to − 0.41); p = 0.001), WOMAC-total score (MD (95% CI): − 9.91 (− 15.05 to − 4.78); p < 0.001), WOMAC-pain subscale (MD (95% CI): − 3.30 (− 5.30 to − 1.29); p = 0.002), WOMAC-physical function (MD(95% CI): − 5.48 (− 9.41 to − 1.53); p = 0.007), depression ( p = 0.003), anxiety ( p = 0.011), QoL-physical functioning (0.041), and QoL-pain (0.010) after the intervention. Conclusion An anti-inflammatory accompanied by a low-calorie diet resulted in greater weight loss and greater improvement in pain intensity, functional status, depression, anxiety, and some dimension of QoL in overweight and obese women with knee OA compared to the low-calorie diet. Trial registration number and date of registration: IRCT201610220030424N2; 2018-04-23. | The effect of an anti-inflammatory in comparison with a low caloric diet on physical and mental health in overweight and obese women with knee osteoarthritis: a randomized clinical trial | 10.1007/s00394-022-03017-4 |
2023-03-01 | The scientific and accurate prediction of suspended sediment concentrations is of great importance for river management in the lower reaches of the Yellow River and for the scheduling of water conservancy projects in the upper and middle reaches. In order to solve the influence of the non-linear and non-smooth characteristics of the suspended sediment concentration series in the lower Yellow River on the prediction results and improve the prediction accuracy, this paper proposes a coupled model based on Complementary Ensemble Empirical Mode Decomposition (CEEMD) and non-linear autoregressive (NAR) model. Take the predicted suspended sediment concentrations in the lower reaches of the Yellow River at the Huayuankou hydrographic station as an example. The accuracy and stability of the coupled CEEMD-NAR model were verified through the Gaocun and Lijin hydrological stations. The CEEMD-NAR model predicted suspended sediment concentrations with a Nash–Sutcliffe efficiency (NSE) factor of 0.93. The three statistical evaluation indicators of the CEEMD-NAR model, mean absolute error (MAE), mean relative error (MRE), and root mean square error (RMSE) were 2.12 kg/m 3 , 1.07, and 3.75 kg/m 3 respectively. In contrast to the NAR, EMD-NAR, and EEMD-NAR models, the coupled CEEMD-NAR model has good stability and high prediction accuracy and can be used in non-linear, non-smooth suspended sediment concentration long series prediction. | Prediction of suspended sediment concentration in the lower Yellow River in China based on the coupled CEEMD-NAR model | 10.1007/s11356-022-24406-6 |
2023-02-28 | Understanding the dynamics of the lithosphere relies heavily on the scale-dependent rheology of minerals. While quartz, feldspar, and phyllosilicates are the key phases to govern the rheology of the crust and tectonic margins, olivine and other mafic phases control the same in the upper mantle. Phase transition, solid-state substitution, polymorphism, etc. also affect mineral phase rheology. High pressure–temperature deformation tests with natural, synthetic and analog materials have improved our interpretation of the geodynamic state of the lithosphere. However, deforming and studying a single crystal is not easy, because of the scarcity of specimens and laborious sample preparations. Experimental micro- to nanoindentation at room and/or elevated temperatures has proven to be a convenient method over mesoscale compressive testing. Micro- to nanoindentation technique enables higher precision, faster data acquisition and ultra-high resolution (nanoscale) load and displacement. Hardness, elastic moduli, yield stress, fracture toughness, fracture surface energy and rate-dependent creep of mono- or polycrystalline minerals are evaluated using this technique. Here, we present a comprehensive assessment of micro- to nano-mechanics of minerals. We first cover the fundamental theories of instrumented indentation, experimental procedures, pre- and post-indentation interpretations using various existing models followed by a detailed discussion on the application of nanoindentation in understanding the rheology and deformation mechanisms of various minerals commonly occur in the crust and upper mantle. We also address some of the major limitations of indentation tests (e.g., indentation size effect). Finally, we suggest potential future research areas in mineral rheology using instrumented indentation. | Nanomechanics of minerals: understandings and developments through instrumented nanoindentation techniques | 10.1007/s00269-023-01235-8 |
2023-02-27 | In this study, the low velocity impact behavior of glass fiber reinforced epoxy (GFRE) composites with the addition of organic intercalated nanoclay and spheroidal powder of polyamide nanoparticles individually and together were investigated experimentally. The weight ratio of the additives was 2% of the epoxy resin-hardener system. Composite laminates were manufactured using prepreg and hot-pressing techniques. Impact tests were carried out at different energy levels from 10 J to 45 J up to complete perforation of the laminates. To evaluate the damage characteristics of the laminates, the results are interpreted in terms of load-time, load-displacement, energy-time, and observation of the physical damages introduced. Addition of nanoparticles increased the peak load (up to 22.6%) and damage resistance (up to 40%) of the GFRE laminates altering damage mechanisms of the composite material from out of plane to in-plane direction at higher impact energy levels. | An experimental study on low velocity impact characteristics of glass fiber reinforced epoxy nanocomposites | 10.1007/s12046-023-02090-7 |
2023-02-27 | We investigate a numerical behavior of robust deterministic optimal control problem subject to a convection-diffusion equation containing uncertain inputs. Stochastic Galerkin approach, turning the original optimization problem containing uncertainties into a large system of deterministic problems, is applied to discretize the stochastic domain, while a discontinuous Galerkin method is preferred for the spatial discretization due to its better convergence behavior for optimization problems governed by convection dominated PDEs. Error analysis is done for the state and adjoint variables in the energy norm, while the estimate of deterministic control is obtained in the L 2 -norm. Large matrix system emerging from the stochastic Galerkin method is addressed by the low-rank version of GMRES method, which reduces both the computational complexity and the memory requirements by employing Kronecker-product structure of the obtained linear system. Benchmark examples with and without control constraints are presented to illustrate the efficiency of the proposed methodology. | Stochastic discontinuous Galerkin methods for robust deterministic control of convection-diffusion equations with uncertain coefficients | 10.1007/s10444-023-10015-5 |
2023-02-25 | The need for high-performance gas sensors is driven by concerns over indoor and outdoor air quality, and industrial gas leaks. Due to their structural diversity, vast surface area, and geometric tunability, metal oxides show significant potential for the development of gas sensing systems. Despite the fact that several previous reports have successfully acquired a suitable response to various types of target gases, it remains difficult to maintain the reliability of metal oxide-based gas sensors. In particular, the degradation of the sensor platform under repetitive operation, such as off-state stress (OSS) causes significant reliability issues. We investigate the impact of OSS on the gas sensing performances, including response, low-frequency noise, and signal-to-noise ratio of horizontal floating-gate field-effect-transistor (FET)-type gas sensors. The 1/ f noise is increased after the OSS is applied to the sensor because the gate oxide is damaged by hot holes. Therefore, the SNR of the sensor is degraded by the OSS. We applied a self-curing method based on a PN-junction forward current at the body–drain junction to repair the damaged gate oxide and improve the reliability of the sensor. It has been demonstrated that the SNR degradation caused by the OSS can be successfully recovered by the self-curing method. | Recovery of off-state stress-induced damage in FET-type gas sensor using self-curing method | 10.1186/s11671-023-03801-z |
2023-02-25 | The high-elasticity bottoms applying gradual pressurization to the blood vessels of the lower extremities simultaneously assisting to both prevention and treatment of multiple health conditions such as varicose veins. Medical compression stockings are classified as medical supplies, and there is a clear standard on magnitude and application for gradual pressure. However, in the case of leggings, there are no relevant experimental data or papers supporting these findings. This study was performed in order to analyse the gradual compression values in legging. Eight types of leggings currently available on the market by different brands, were analysed to determine the type of pressure applied. The pressure was measured at five points of the clothed body with leggings pulled across lower extremities. An airpack sensor was attached to a wooden leg model and five consecutive records at each measuring point were taken. Afterwards the average values were calculated. As observed in all eight leggings, the measuring point with the highest pressure applied was the back of the calf (mean 18.25 mmHg) or the below the knee circumference (mean 13.83 mmHg), pointing to deviance in applying gradual pressure as proposed in medical compression stockings. The commercial leggings used in this experiment did not show a gradual increase in pressure from the thigh to the ankle body zone. One can presume that the legs’ fatigue would increase over the time. Since, the gradual pressure should be applied in legging construction as seen in medical compression stockings. | Clothing pressure analysis of commercial women's leggings for applying medical compression classes | 10.1186/s40691-022-00324-6 |
2023-02-25 | Background Residents of informal settlements in Sub-Sahara Africa (SSA) are vulnerable to the health impacts of climate change. Little is known about the knowledge, attitudes and practices (KAP) of inhabitants of informal settlements in SSA regarding climate change and its health impacts. The aim of this study was to investigate how inhabitants of an informal settlement in SSA experience climate change and its health impacts and assess related knowledge, attitudes and practices. The study was conducted in Mukuru informal settlement in Nairobi City County, Kenya. Methods A cross-sectional study was conducted in September 2021 using a structured, semi-closed KAP questionnaire. Inclusion criteria were ≥ 18 years of age and living in one of the three main sections in Mukuru: Kwa Njenga, Kwa Reuben or Viwandani. By spinning a pen at the geographic centre of each section, a random direction was selected. Then, in every second household one individual was interviewed, creating a representative mix of ages and genders of the local community. To assess participant characteristics associated with climate change knowledge multivariable logistic regression was used. Thematic content analysis was performed for qualitative responses. Results Out of 402 study participants, 76.4% ( n = 307) had heard of climate change before the interview, 90.8% ( n = 365) reported that climate change was affecting their community, and 92.6% ( n = 372) were concerned with the health-related impact of climate change. Having lived in Mukuru for more than 10 years and living in a dwelling close to the riverside were factors significantly associated with having heard of climate change before (aOR 3.1, 95%CI 1.7 – 5.8 and aOR 2.6, 95%CI 1.1 – 6.1, respectively) and experiencing a climate change related impact on the community (aOR 10.7, 95%CI 4.0 – 28.4 and aOR 7.7; 95%CI 1.7 – 34.0, respectively). Chronic respiratory conditions, vector-borne diseases, including infectious diarrhoea, malnutrition and cardiovascular diseases were identified by respondents as climate related health risks. Conclusions Most respondents were knowledgeable about climate change and were experiencing its (health-related) impact on their community. This study provides insights which may prove useful for policy makers, intervention planners and researchers to work on locally adapted mitigation and adaption strategies. | Climate change and health risks in Mukuru informal settlement in Nairobi, Kenya – knowledge, attitudes and practices among residents | 10.1186/s12889-023-15281-y |
2023-02-24 | Pure and Mg-substituted AgCaVO 4 compounds were explored using the conventional solid-state sintering method and their microwave dielectric properties were investigated. The XRD patterns indicate all samples belong to an orthorhombic structure with a space group of Pmna. The pure AgCaVO 4 ceramic gives the dielectric properties: ε r of 11.7, Q × f of 15,000 GHz, and τ f of38 ppm/°C at 530 °C. The value of τ f is correlated with the bond valence. In a limited range ( x = 0.03–0.05), a small amount of Mg substitution can not only reduce the dielectric loss, but also increase the dielectric constant of the AgCa 1− x Mg x VO 4 specimen. AgCa 0.97 Mg 0.03 VO 4 ceramic sintered at 530 °C exhibits optimum properties of ε r = 12, Q × f = 23,000 GHz and τ f = –35 ppm/°C at microwave frequencies. The ceramic also shows good chemical compatibility with aluminum, providing a promising candidate for ULTCC applications. | Low-loss and ultra-low sintering temperature ceramics of AgCa1−xMgxVO4 (x = 0–0.09) for microwave applications | 10.1007/s00339-023-06501-8 |
2023-02-22 | Background Citizen science as an approach to merge society and science is not a new paradigm. Yet it is not common in public health, epidemiology, or medical sciences. SMARAGD (Sensors for Measuring Aerosols and ReActive Gases to Deduce health effects) assesses air pollution at participants’ homes or workplaces in Cologne, Germany, as feasibility study with a citizen science approach. Personal exposure to air pollutants is difficult to study, because the distribution of pollutants is heterogeneous, especially in urban areas. Targeted data collection allows to establish connections between air pollutant concentration and the health of the study population. Air pollution is among the most urgent health risks worldwide. Yet links of individualized pollution levels and respiratory infections remain to be validated, which also applies for the feasibility of the citizen science approach for epidemiological studies. Methods We co-designed a prospective feasibility study with two groups of volunteers from Cologne, Germany. These citizen scientists and researchers determined that low-cost air-quality sensors (hereafter low-cost sensors) were to be mounted at participants’ homes/workplaces to acquire stationary data. The advantage of deploying low-cost sensors is the achievable physical proximity to the participants providing health data. Recruitment started in March 2021 and is currently ongoing (as of 09/22). Sensor units specifically developed for this study using commercially available electronic sensor components will measure particulate matter and trace gases such as ozone, nitrogen oxides, and carbon monoxide. Health data are collected using the eResearch system “Prospective Management and Monitoring-App” (PIA). Due to the ongoing SARS-CoV-2 pandemic, we also focus on COVID-19 as respiratory infection. Discussion Citizen science offers many benefits for science in general but also for epidemiological studies. It provides scientific information to society, enables scientific thinking in critical discourses, can counter anti-scientific ideologies, and takes into account the interests of society. However, it poses many challenges, as it requires extensive resources from researchers and society and can raise concerns regarding data protection and methodological challenges such as selection bias. | Merging citizen science with epidemiology: design of a prospective feasibility study of health events and air pollution in Cologne, Germany | 10.1186/s40814-023-01250-0 |
2023-02-21 | This paper presents an assessment of the start-up performance of aerobic granular sludge (AGS) for the treatment of low-strength (chemical oxygen demand, COD < 200 mg/L) domestic wastewater by the application of a diatomite carrier. The feasibility was evaluated in terms of the start-up period and stability of the aerobic granules as well as COD and phosphate removal efficiencies. A single pilot-scale sequencing batch reactor (SBR) was used and operated separately for the control granulation and granulation with diatomite. Complete granulation (granulation rate ≥ 90%) was achieved within 20 days for the case of diatomite with an average influent COD concentration of 184 mg/L. In comparison, control granulation required 85 days to accomplish the same feat with a higher average influent COD concentration (253 mg/L). The presence of diatomite solidifies the core of the granules and enhances physical stability. AGS with diatomite recorded the strength and sludge volume index of 18 IC and 53 mL/g suspended solids (SS) which is superior to control AGS without diatomite (19.3 IC, 81 mL/g SS). Quick start-up and achievement of stable granules lead to an efficient COD (89%) and phosphate removal (74%) in 50 days of bioreactor operation. Interestingly, this study revealed that diatomite has some special mechanism in enhancing the removal of both COD and phosphate. Also, diatomite has a significant influence on microbial diversity. The result of this research implies that the advanced development of granular sludge by using diatomite can provide promising low-strength wastewater treatment. | Aerobic granular sludge development using diatomite for low-strength wastewater treatment | 10.1007/s10661-023-11028-9 |
2023-02-21 | Background Globally, millions of patients suffer from regenerative deficiencies, such as refractory wound healing, which is characterized by excessive inflammation and abnormal angiogenesis. Growth factors and stem cells are currently employed to accelerate tissue repair and regeneration; however, they are complex and costly. Thus, the exploration of new regeneration accelerators is of considerable medical interest. This study developed a plain nanoparticle that accelerates tissue regeneration with the involvement of angiogenesis and inflammatory regulation. Methods Grey selenium and sublimed sulphur were thermalized in PEG-200 and isothermally recrystallised to composite nanoparticles (Nano-Se@S). The tissue regeneration accelerating activities of Nano-Se@S were evaluated in mice, zebrafish, chick embryos, and human cells. Transcriptomic analysis was performed to investigate the potential mechanisms involved during tissue regeneration. Results Through the cooperation of sulphur, which is inert to tissue regeneration, Nano-Se@S demonstrated improved tissue regeneration acceleration activity compared to Nano-Se. Transcriptome analysis revealed that Nano-Se@S improved biosynthesis and ROS scavenging but suppressed inflammation. The ROS scavenging and angiogenesis-promoting activities of Nano-Se@S were further confirmed in transgenic zebrafish and chick embryos. Interestingly, we found that Nano-Se@S recruits leukocytes to the wound surface at the early stage of regeneration, which contributes to sterilization during regeneration. Conclusion Our study highlights Nano-Se@S as a tissue regeneration accelerator, and Nano-Se@S may provide new inspiration for therapeutics for regenerative-deficient diseases. Graphical Abstract | Turning gray selenium and sublimed sulfur into a nanocomposite to accelerate tissue regeneration by isothermal recrystallization | 10.1186/s12951-023-01796-4 |
2023-02-20 | Background Formula-fed infants are at increased risk of infections. Due to the cross-talk between the mucosal systems of the gastrointestinal and respiratory tracts, adding synbiotics (prebiotics and probiotics) to infant formula may prevent infections even at distant sites. Infants that were born full term and weaned from breast milk were randomized to prebiotic formula (fructo- and galactooligosaccharides) or the same prebiotic formula with Lactobacillus paracasei ssp. paracasei F19 (synbiotics) from 1 to 6 months of age. The objective was to examine the synbiotic effects on gut microbiota development. Results Fecal samples collected at ages 1, 4, 6, and 12 months were analyzed using 16S rRNA gene sequencing and a combination of untargeted gas chromatography-mass spectrometry/liquid chromatography-mass spectrometry. These analyses revealed that the synbiotic group had a lower abundance of Klebsiella , a higher abundance of Bifidobacterium breve compared to the prebiotic group, and increases in the anti-microbial metabolite d-3-phenyllactic acid. We also analyzed the fecal metagenome and antibiotic resistome in the 11 infants that had been diagnosed with lower respiratory tract infection (cases) and 11 matched controls using deep metagenomic sequencing. Cases with lower respiratory tract infection had a higher abundance of Klebsiella species and antimicrobial resistance genes related to Klebsiella pneumoniae , compared to controls. The results obtained using 16S rRNA gene amplicon and metagenomic sequencing were confirmed in silico by successful recovery of the metagenome-assembled genomes of the bacteria of interest. Conclusions This study demonstrates the additional benefit of feeding specific synbiotics to formula-fed infants over prebiotics only. Synbiotic feeding led to the underrepresentation of Klebsiella , enrichment of bifidobacteria, and increases in microbial degradation metabolites implicated in immune signaling and in the gut-lung and gut-skin axes. Our findings support future clinical evaluation of synbiotic formula in the prevention of infections and associated antibiotic treatment as a primary outcome when breastfeeding is not feasible. Trial registration ClinicalTrials.gov NCT01625273 . Retrospectively registered on 21 June 2012. | Targeting the gut-lung axis by synbiotic feeding to infants in a randomized controlled trial | 10.1186/s12915-023-01531-3 |
2023-02-20 | To investigate the effect of low-level laser therapy (LLLT) on orthodontic tooth movement during maxillary molar distalization over a 12-week observation period. Twenty patients were enrolled in this clinical trial. On the 0th, 3rd, 7th, 14th, 21st, 42nd, and 63rd days following the initial activation of the distalization appliance, laser therapy was applied in a total of 16 different points of the first and second molars for 10 s per point to the randomly determined molar region of the individuals in the intervention group. The amount of molar distalization was measured using digital scans of the three-dimensional (3D) digital models obtained during the 3rd, 6th, 9th, and 12th weeks. The amount of tooth movement on the laser-applied side of subjects in the intervention group was significantly greater than those in the contralateral and control groups at all time intervals ( p < 0.001). The amount of tooth movement between the contralateral side of the intervention group and the control group was determined to be statistically insignificant ( p > 0.05) at all time intervals. The laser-treated molars of the subjects in the intervention group moved 1.22 times more than the molars in the contralateral side and in the control group in 12 weeks. The rate of tooth movement in the laser, contralateral, and control groups was 0.033, 0.027, and 0.027 mm/day, respectively. Although LLLT was found to be statistically significant in terms of accelerating tooth movement, the effect of LLLT is not considered to be clinically significant. This trial was retrospectively registered (September 22, 2022) at Clinical-Trials.gov (Ref no: NCT05550168). | Effect of low-level laser therapy on orthodontic tooth movement during miniscrew-supported maxillary molar distalization in humans: a single-blind, randomized controlled clinical trial | 10.1007/s10103-023-03736-y |
2023-02-18 | Physical separation of the organic and inorganic constituents in coal mostly depends on the degree of association and the manner of their distribution. The liberation of macerals and minerals in coal holds a vital role in the effectiveness of coal-washing technologies. The intent of the study is to observe the effect of particle size on the distribution of both macerals and minerals in coal. Different size fractions were generated, viz. −3350+1000μm, −1000+500μm, −500+212μm, −212+150μm, 150+75μm, 75+45μm and −45μm by using Indian standard sieves. Petrographic studies were carried out for all the size fractions to understand the distribution and the degree of liberation of macerals and minerals with respect to particle sizes. The results showed that the concentration of vitrinite gradually increases while inertinite and liptinite decrease with the decrease in particle size. Mineral matters decrease/increase with particle size depending upon the nature of associated minerals. Also, the particle size influences the type of mineral matter association depending upon their hardness. | Influence of particle size on maceral and mineral distribution in Lower Gondwana coals of India | 10.1007/s12517-023-11286-4 |
2023-02-17 | Background Low temperatures are known to limit the growth and geographical distribution of poplars. Although some transcriptomic studies have been conducted to explore the response of poplar leaves to cold stress, only a few have comprehensively analyzed the effects of low temperature on the transcriptome of poplars and identified genes related to cold stress response and repair of freeze–thaw injury. Results We exposed the Euramerican poplar Zhongliao1 to low temperatures; after stems were exposed to − 40℃, 4℃, and 20℃, the mixture of phloem and cambium was collected for transcriptome sequencing and bioinformatics analysis. A total of 29,060 genes were detected, including 28,739 known genes and 321 novel genes. Several differentially expressed genes (n = 36) were found to be involved in the Ca 2+ signaling pathway, starch–sucrose metabolism pathway, abscisic acid signaling pathway, and DNA repair. They were functionally annotated; glucan endo-1,3-beta-glucosidase and UDP-glucuronosyltransferase genes, for instance, showed a close relationship with cold resistance. The expression of 11 differentially expressed genes was verified by qRT-PCR; RNA-Seq and qRT-PCR data were found to be consistent, which validated the robustness of our RNA-Seq findings. Finally, multiple sequence alignment and evolutionary analysis were performed, the results of which suggested a close association between several novel genes and cold resistance in Zhongliao1. Conclusion We believe that the cold resistance and freeze–thaw injury repair genes identified in this study are of great significance for cold tolerance breeding. | Transcriptome analysis of Populus × canadensis ‘Zhongliao1’ in response to low temperature stress | 10.1186/s12864-023-09187-7 |
2023-02-16 | Low phosphorus (P) is one of the limiting factors in sustainable cotton production. However, little is known about the performance of contrasting low P tolerant cotton genotypes that might be a possible option to grow in low P condition. In the current study, we characterized the response of two cotton genotypes, Jimian169 a strong low P tolerant, and DES926 a weak low P tolerant genotypes under low and normal P conditions. The results showed that low P greatly inhibited growth, dry matter production, photosynthesis, and enzymatic activities related to antioxidant system and carbohydrate metabolism and the inhibition was more in DES926 as compared to Jimian169. In contrast, low P improved root morphology, carbohydrate accumulation, and P metabolism, especially in Jimian169, whereas the opposite responses were observed for DES926. The strong low P tolerance in Jimian169 is linked with a better root system and enhanced P and carbohydrate metabolism, suggesting that Jimian169 is a model genotype for cotton breeding. Results thus indicate that the Jimian169, compared with DES926, tolerates low P by enhancing carbohydrate metabolism and by inducing the activity of several enzymes related to P metabolism. This apparently causes rapid P turnover and enables the Jimian169 to use P more efficiently. Moreover, the transcript level of the key genes could provide useful information to study the molecular mechanism of low P tolerance in cotton. | Phosphorus and carbohydrate metabolism contributes to low phosphorus tolerance in cotton | 10.1186/s12870-023-04100-6 |
2023-02-15 | We derive the necessary and sufficient conditions for a 2 d QCD theory of massless gluons and left and right chiral quarks in arbitrary representations of a gauge group G to develop a mass gap. These results are obtained from spectral properties of the lightcone and temporal QCD Hamiltonians. The conditions can be explicitly solved, and we provide the complete list of all 2 d QCD theories that have a quantum mechanical gap in the spectrum, while any other theory not in the list is gapless. The list of gapped theories includes QCD models with quarks in vector-like as well as chiral representations. The gapped theories consist of several infinite families of classical gauge groups with quarks in rank 1 and 2 representations, plus a finite number of isolated cases. We also put forward and analyze the effective infrared description of QCD — TQFTs for gapped theories and CFTs for gapless theories — and exhibit several interesting features in the infrared, such as the existence of non-trivial global ’t Hooft anomalies and emergent supersymmetry. We identify 2 d QCD theories that flow in the infrared to celebrated CFTs such as minimal models, bosonic and supersymmetric, and Wess-Zumino-Witten and Kazama-Suzuki models. | Infrared phases of 2d QCD | 10.1007/JHEP02(2023)157 |
2023-02-13 | Throughout the world, the use of water resources is increasing with industrial development, agro-food, and economic and demographic growth, which causes the degradation of their quality by polluted discharges. This requires controls and monitoring of these natural resources. In order to develop a diagnostic of the level of pollution of the waters of these rivers and to evaluate the health risks, this work’s focus was on the characterization of pollution by metallic trace elements (chromium, lead, and copper) of surface waters in the major Moroccan rivers. In addition, it should be noted that the analysis of metallic elements in sediments is an indicator of contamination of river water by trace metals. The chosen approach focused first on analyzing samples by inductively coupled plasma mass spectrometry. In this sense, six sampling campaigns were carried out at two campaigns per watercourse (dry period and wet period). All the samples analyzed for chromium are of good quality, with average concentrations of 1.75 µg/l for the lower Moulouya and 3.4 µg/l for Oum Er Rbia. On the other hand, 64% of the samples taken at the level of the Sebou are of poor quality with an average concentration of 181.25 µg/l, which exceeds three times the standard (50 µg/l). Regarding lead and copper, the analysis results show that the average concentrations are always lower than the quality values (average to excellent for the three rivers). The electrical conductivity values recorded in Oum Er Rbia and lower Moulouya are very high; 71% of the water analyzed in lower Moulouya is of poor quality. To perform this work, the results obtained were analyzed by calculating the existing correlations between the various parameters studied and determining the water pollution index to calculate the overall quality in each sampling station. It can be deduced that the water pollution index in the three rivers studied indicates that the overall quality of the Sebou varies from pure to heavily contaminated. In Oum Er Rbia, the quality is pure to moderately polluted, while in lower Moulouya the quality is pure for all sampling points. | Assessment of the water quality in the main rivers of Morocco | 10.1007/s12517-023-11208-4 |
2023-02-13 | Shaly sandstone reservoir is one of the most significant targets in petroleum and gas exploration. However, the influences of various factors on the resistivity of irregular laminated shaly sandstone are yet to be determined, and it is extremely challenging to accurately calculate the water saturation. By considering shaly sandstone in Zhujiang Formation of Neogene in Pearl River Mouth Basin as an example, this research extracts the shale distribution form and the pore structure by image processing, simulates the resistivity of rock by finite element method, analyzes the influence of shale parameters on resistivity, and deduces the water saturation equation of shaly sandstone. Results show that, in shaly sandstone, shale distributes in irregular laminated patterns on a millimeter scale. The other clean sandstone areas have high porosity and the capacity to reserve oil and gas. At high water saturation states, the shaly sandstone mainly conducts electricity in the clean sandstone area and various shale parameters have minor influences on the resistivity of shaly sandstone. At low water saturation states, the shaly sandstone mainly conducts electricity in the shale area, the resistivity of shaly sandstone is very close to the resistivity of the water layer, and the reservoir is the so-called low resistivity reservoir. The conductive form of clean sandstone area and shale laminae tends to parallel but remains a noticeable difference from total parallel. The simulation results deduced that the water saturation equation of shaly sandstone is more accurate than other equations, which provides an innovative mindset to calculate the water saturation of shaly sandstone. Three types of conduction models at different scales are proposed and combined to simulate the resistivity of shaly sandstone. Shale content and homogeneity of shale laminae have the greatest influence on the resistivity of irregular laminated shaly sandstone. A new water saturation equation is proposed based on numerical simulation and considering the conductivity of shale laminae. | Finite element method-based resistivity simulation and water saturation calculation of irregular laminated shaly sandstone | 10.1007/s40948-023-00544-0 |
2023-02-13 | Purpose Vulvovaginal candidiasis (VVC) is a mucosal infection of the female lower genital tract for which treatment using conventional antifungal drugs shows limited effectiveness. Herein, amphotericin B-loaded poly(lactic-co-glycolic acid)-polyethylene glycol (PLGA-PEG) nanoparticles (AmB-NPs) were fabricated and combined with low intensity ultrasound (US) to mediate AmB-NPs intravaginal drug delivery to achieve productive synergistic antifungal activity in a rabbit model of VVC. Methods Polymeric AmB-NPs were fabricated by a double emulsion method and the physical characteristics and biosafety of nanoparticles were analyzed. The distribution and tissue permeability of nanoparticles after intravaginal ultrasound irradiation (1.0 MHz, 1.0 W/cm 2 , 5 min, 50% duty ratio) were observed in the vagina. The synergistic therapeutic activity of US-mediated AmB-NPs treatment was evaluated using an experimental rabbit model of VVC. Vaginal C. albicans colony counts, the pathological structure of the vagina epithelium, and Th1/Th2/Th17-type cytokine and oxidative stress levels were analyzed to investigate the therapeutic effect in vivo. Results The prepared AmB-NPs showed an obvious shell and core structure with uniform size and good dispersion and displayed high biosafety and US-sensitive slow drug release. Ultrasound significantly enhanced nanoparticle transport through the mucus and promoted permeability in the vaginal tissue. US-mediated AmB-NPs treatment effectively increased drug sensitivity, even in the presence of the vaginal mucus barrier in vitro. On the seventh day after treatment in vivo, the combination treatment of AmB-NPs and US significantly reduced the fungal load in the vagina, achieving over 95% clearance rates, and also improved the pathological epithelium structural damage and glycogen secretion function. The expression of Th1 (IFN-γ, IL-2) and Th17 (IL-17) cytokines were significantly increased and Th2 (IL-6, IL-10) cytokines significantly decreased in the US + AmB-NP group. Furthermore, US-mediated AmB-NPs treatment effectively increased C. albicans intracellular reactive oxygen species (ROS) levels and promoted vaginal oxidation and antioxidants to normal levels. Conclusion US-mediated drug-loaded nanoparticles with intravaginal drug delivery exhibited a productive synergistic antifungal effect, which may provide a new non-invasive, safe, and effective therapy for acute or recurrent fungal vaginitis. Graphical Abstract | Low intensity ultrasound-mediated drug-loaded nanoparticles intravaginal drug delivery: an effective synergistic therapy scheme for treatment of vulvovaginal candidiasis | 10.1186/s12951-023-01800-x |
2023-02-09 | Archaeological objects based on copper alloys (such as bronze wares) usually suffer from “bronze disease” that results from the existence of CuCl on the surfaces. The surface-coating Cu 2 (OH) 3 Cl can release Cl − and lead to further corrosion during the storage procedure. The central aim of the work is the verity the effectiveness of low-temperature radio-frequency (RF) plasma for the removal of CuCl and Cu 2 (OH) 3 Cl from the bronze wares. In this work, CuCl and Cu 2 (OH) 3 Cl patina were synthesized on copper by a simple solution method. The chemical and aesthetic features before and after plasma treatment were characterized using optical microscopy (OM), SEM-EDS, XRD, and XPS. The results show that Ar-H 2 plasma could reduce the CuCl to Cu efficiently, which achieves pleasing esthetics as well as removes the chlorine (Cl atomic ratio decrease from 46.0 to 3.6%). For Cu 2 (OH) 3 Cl, the air plasma treatment exhibit better performance compared to the Ar-H 2 plasma treatment, judging from the aesthetic effect and the removal effect of chlorine (Cl atomic ratio decrease from 14.8 to 3.3%). | Application of low-temperature plasma for the removal of copper chloride layers on bronze Wares | 10.1186/s40494-022-00839-7 |
2023-02-08 | Autoclaved aerated concrete (AAC) is the lightest masonry material available in today’s building industry. It shows properties, such as high strength per unit weight, lesser density, lower shrinkage, higher thermal insulation, and fire resistance as compared to traditional concrete. Not only engineering properties of AAC make it popular in construction industry, but also its eco-friendly nature also contributes in conservation of energy. AAC produces about 67% lower carbon emission than the clay bricks. Consequently, it becomes a cost-effective product which reduces the cost of construction. This paper provides thorough insight into possible solutions for the waste utilization. It has been inferred that fine aggregates can be replaced by these wastes in the preparation of AAC. This replacement will improve its physio-mechanical properties, such as bulk-density, moisture absorption, compressive strength, along with microstructure. These properties are comprehensively presented to categorize the investigation which has been done in such fields earlier. The ongoing research work at the author’s institute, i.e., the development of lightweight concrete by using different kind of waste materials, such as marble slurry, fly ash, etc., is being presented. Graphical Abstract The paper presents the feasibility to use different agro-industrial wastes to develop AAC. Studies on the effect of fiber reinforcement on the physio-mechanical properties of AAC have been discussed. Ca/Si ratio affects the tobermorite formation and the mineralogy of AAC. Influence of porosity on the microstructure of AAC has been investigated. Ongoing R&D work at the author’s institute has been described. | Utilization of Solid Waste in the Production of Autoclaved Aerated Concrete and Their Effects on its Physio-mechanical and Microstructural Properties: Alternative Sources, Characterization, and Performance Insights | 10.1186/s40069-022-00569-x |
2023-02-07 | Four samples were prepared by the same synthetic process with paraffinic oil, naphthenic oil, poly-α-olefin oil (PAO), and polyol ester oil (POE), respectively, and using nano-silica as the thickener. For the samples prepared into nano-silica greases (NSGs) successfully, their physiochemical properties, rheological behaviors, low-temperature fluidities, and tribological properties were investigated. Based on the materials and preparation methods selected in this experiment, it has been found that the polyol ester oil could not be prepared into NSGs and the paraffinic oil-based grease had the best colloid stability among the three greases successfully prepared. SEM analysis revealed that NSGs synthesized by different base oils had a similar chain skeleton structure. Moreover, the properties of base oils and their sensitivities to nanoparticles (nano-thickeners) determined the structural strength and thixotropy of the as-prepared NSGs. The low-temperature fluidity test also showed that PAO-based grease has the best pumpability. In addition, the tribological properties of greases were different from the corresponding base oils, which might be caused by the change of the structure after the preparation of greases and the participation of nano-silica in the friction process. This study provided guidance in selecting base oils for the development of high-performance NSGs. | Effect of Base Oil on Rheological Behaviors and Tribological Properties of Nano-silica Greases | 10.1007/s40735-023-00742-z |
2023-02-07 | Bio-cementation of natural sand is a prospective solution to improve their engineering properties. The enhancement of strength and low-strain shear modulus is considered to be of high engineering significance for improvement in the performance of sand under both static and dynamic loading. In the present study, bio-cementation effects of bacillus Sporosarcina pasteurii bacteria on standard Ennore sand of India are studied at the microstructure level through scanning electron microscope (SEM) investigation considering microbial-induced calcite precipitation (MICP) technique. The crystallographic structure of the bio-cemented sand is reported through X-ray diffraction (XRD) analyses. Stress–strain behaviour and improvement in the strength of bio-cemented sand with different pore volumes of cementation solution have been investigated through unconfined compression strength (UCS) testing. Finally, the shear wave velocity values of the bio-cemented sand are assessed through bender element testing for different confining pressures, and low-strain shear modulus values have arrived. The study is believed to be helpful in the quantification of improvement of strength and low-strain shear modulus values of bio-cemented sand. | Assessment of strength and low-strain shear modulus of bio-cemented sand considering MICP treatment | 10.1007/s12665-023-10780-y |
2023-02-07 | To study the removal of nitrogen and phosphorus from low C/N ratio rural domestic sewage by Fe–C mixed fillers, in this study, a laboratory-scale iron-carbon microelectronics system (IC-ME) and an activated carbon system (AC) were established to purify rural domestic sewage with a C/N ratio of 1.9–4.4. The results show that the removal rates of NO 3 − -N, total nitrogen (TN), and total phosphorus (TP) of the IC-ME system are 89.25%, 80.64%, and 92.2%, respectively. During the hydraulic retention time (HRT) of 36 h, when the C/N ratio is 1.9. They are much higher than those of the AC system (NO 3 − -N: 31.09%; TN: 64.15%; TP: 26.34%). All the indicators reached the first class B standard of “Pollutant Discharge Standard of Urban Sewage Treatment Plant” (GB18918-2002) and the first-level discharge standard of Guangxi’s “Water Pollutants Discharge Standard for Rural Domestic Sewage Treatment Facilities” (DB45/2413–2021). Micro-electrolysis can provide electrons for denitrification, further facilitating the process. In addition, the effective phosphorus removal is caused primarily by the corrosion of the iron anodes, which produces Fe 2+ and Fe 3+ ions. These ions then react with PO 4 3− to form phosphate precipitates, and at the same time, create Fe(OH) 3 /Fe(OH) 2 colloids with OH − in the water, which can adsorb and flocculate organic phosphorus and PO 4 3− . Based on high-throughput sequencing studies, the microbial abundance of Bacteroidetes , Chloroflexi , and Firmicutes is much higher in the IC-ME system than in the AC system. Overall, the IC-ME process provides a new strategy for treating domestic wastewater in rural areas with low C/N ratios. | Study on the Effect of Iron-Carbon Micro-electrolysis Process on the Removal of Nitrogen and Phosphorus from Rural Domestic Wastewater with Low Carbon to Nitrogen Ratio | 10.1007/s11270-023-06131-z |
2023-02-07 | To realize maximum benefits and minimize environment pollution, the eco-efficiency of cultivated land utilization (ECLU) is becoming a vital indicator in weighing the rationality of regional land use. Scientific analysis of spatial–temporal pattern variations, as well as factors influencing the ECLU, is of great significance to cultivated land protection, economic development and ecological environment protection in black soil region of Northeast China, and has become a global strategic issue related to the sustainable development. However, assessments of the indicators are still incomplete, the lack of information may inhibit planning guideline for the sustainable development of cultivated land resources. Thus, this study attempts to fill the gaps by incorporating the net carbon sink and non-point source pollution emissions into the measurement framework of ECLU. The super-efficiency slack-based measure (SBM) model with undesirable output and the Malmquist–Luenberger (ML) index were used to measure the ECLU and changes in the total factor productivity (TFP) of cultivated land use in the Songnen Plain from 1989 to 2019. Moran index and LISA clustering were used to reveal spatial correlation of ECLU, and Kernel density estimation, and trend surface analysis maps were drawn to analyze variation tendency of the ECLU. Geographical detector model was employed to further analyze the influencing factors of ECLU. The study results revealed that: (1) The ECLU showed an overall development trend of "rising first and then declining", all of which were below the frontier efficiency. (2) The polarization of ECLU is prominent, and the ECLU had a significant heterogeneity and spatial correlation. (3) The TFP showing an increasing trend, technological progress is the main driving force to promote the progress of TFP, while the technological efficiency is the bottleneck for increasing the TFP of the cultivated land use. (4) According to the magnitude of influencing factor, increasing agricultural science and technology investments, lowering carbon emission, and controlling agrochemical investment could significantly enhance the ECLU. These findings have important implications for promoting high-efficient, low-carbon utilization of cultivated land resources and sustainable regional development in black soil region of Northeast China. | Exploring the eco-efficiency of cultivated land utilization and its influencing factors in black soil region of Northeast China under the goal of reducing non-point pollution and net carbon emission | 10.1007/s12665-023-10770-0 |
2023-02-07 | Non-invasive laser irradiation can induce photobiomodulation (PBM) effects in cells and tissues, which can help reduce inflammation and pain in several clinical scenarios. The purpose of this study is to review the current literature to verify whether PBM can produce dose effects in anti-inflammatory experiments by summarizing the clinical and experimental effects of different laser parameters of several diseases. The so-called Arndt-Schulz curve is often used to describe two-phase dose reactions, assuming small doses of therapeutic stimulation, medium doses of inhibition, and large doses of killing. In the past decade, more and more attention has been paid to the clinical application of PBM, especially in the field of anti-inflammation, because it represents a non-invasive strategy with few contraindications. Although there are different types of lasers available, their use is adjusted by different parameters. In general, the parameters involved are wavelength, energy density, power output, and radiation time. However, due to the biphasic effect, the scientific and medical communities remain puzzled by the ways in which the application of PBM must be modified depending on its clinical application. This article will discuss these parameter adjustments and will then also briefly introduce two controversial theories of the molecular and cellular mechanisms of PBM. A better understanding of the extent of dualistic dose response in low-intensity laser therapy is necessary to optimize clinical treatment. It also allows us to explore the most dependable mechanism for PBM use and, ultimately, standardize treatment for patients with various diseases. | Biphasic dose response in the anti-inflammation experiment of PBM | 10.1007/s10103-022-03664-3 |
2023-02-06 | In this paper, the periodic traveling wave solution for a reaction–diffusion SIR epidemic model with demography and time-periodic coefficients is investigated. Because the traveling wave system of non-autonomous reaction–diffusion model is a partial differential equation system, some traditional methods using only the theory of ordinary differential equations are no longer applicable. To overcome these difficulties, the traditional methods are extended and improved, and some new techniques are introduced. The research results show that the existence and nonexistence of traveling wave solutions are determined by the basic reproduction number $${\mathcal {R}}_0$$ R 0 and the minimal wave speed $$c^*$$ c ∗ . Specifically, when $${\mathcal {R}}_0>1$$ R 0 > 1 and the wave speed $$c>c^*$$ c > c ∗ the existence of periodic traveling wave solutions is proved by means of auxiliary system, upper–lower solutions, fixed-point theorems and some limit arguments. Otherwise, when $$R_0<1$$ R 0 < 1 , for any wave speed $$c>0$$ c > 0 the nonexistence of periodic traveling wave solutions is proved. Lastly, the numerical examples are carried out to verify the theoretical results. | Wave propagation in a diffusive epidemic model with demography and time-periodic coefficients | 10.1007/s00033-023-01953-7 |
2023-02-05 | Background In recent years, there has been significant research progress on in situ articular cartilage (AC) tissue engineering with endogenous stem cells, which uses biological materials or bioactive factors to improve the regeneration microenvironment and recruit more endogenous stem cells from the joint cavity to the defect area to promote cartilage regeneration. Method In this study, we used ECM alone as a bioink in low-temperature deposition manufacturing (LDM) 3D printing and then successfully fabricated a hierarchical porous ECM scaffold incorporating GDF-5. Results Comparative in vitro experiments showed that the 7% ECM scaffolds had the best biocompatibility. After the addition of GDF-5 protein, the ECM scaffolds significantly improved bone marrow mesenchymal stem cell (BMSC) migration and chondrogenic differentiation. Most importantly, the in vivo results showed that the ECM/GDF-5 scaffold significantly enhanced in situ cartilage repair. Conclusion In conclusion, this study reports the construction of a new scaffold based on the concept of in situ regeneration, and we believe that our findings will provide a new treatment strategy for AC defect repair. | Hierarchical porous ECM scaffolds incorporating GDF-5 fabricated by cryogenic 3D printing to promote articular cartilage regeneration | 10.1186/s40824-023-00349-y |
2023-02-05 | Background With the high frequency of acute respiratory infections in children worldwide, particularly so in low-resource countries, the development of effective diagnostic support is crucial. While pulse oximetry has been found to be an acceptable method of hypoxemia detection, improving clinical decision making and efficient referral, many healthcare set ups in low- and middle-income countries have not been able to implement pulse oximetry into their practice. Main body A review of past pulse oximetry implementation attempts in low- and middle-income countries proposes the barriers and potential solutions for complete integration in the healthcare systems. The addition of pulse oximetry into WHO health guidelines would prove to improve detection of respiratory distress and ensuing therapeutic measures. Incorporation is limited by the cost and unavailability of pulse oximeters, and subsequent oxygen accessibility. This restriction is compounded by the lack of trained personnel, and healthcare provider misconceptions. These hurdles can be combated by focus on low-cost devices, and cooperation at national levels for development in healthcare infrastructure, resource transport, and oxygen delivery systems. Conclusion The implementation of pulse oximetry shows promise to improve child morbidity and mortality from pneumonia in low- and middle-income countries. Steady measures taken to improve access to pulse oximeters and oxygen supplies, along with enhanced medical provider training are encouraging steps to thorough pulse oximetry integration. | Pulse oximetry: why oxygen saturation is still not a part of standard pediatric guidelines in low-and-middle-income countries (LMICs) | 10.1186/s41479-023-00108-6 |
2023-02-03 | Polyurethane-based adhesives are applied on the windshields of vehicles in the automotive industry to fix the windshield and seal the cabin. A failure in the adhesive bead could allow water to ingress between the windshield and the vehicle body. If not detected in the leak test, it can lead to high cost due to warranty repairs, inconvenience to customers and damage to the brand. Commercial solutions are available in the market to detect an interruption in the adhesive bead right after its application on the windshield, before it is fitted to the vehicle, but at high cost. This paper proposes an automatic inspection system based on computer vision, low-cost hardware, programming in Python language and making use of open-source libraries. A batch of defect-free windshields was inspected using the proposed inspection system. In the impossibility of obtaining defective parts for validation, windshield images were modified to simulate defects and the images were evaluated by the developed algorithm. The algorithm showed quite good results at the end, and we could establish the system's effectiveness at 100% for defect detection capability and 21% of false detections. | Automatic inspection system of adhesive on vehicle windshield using computational vision | 10.1007/s40430-023-04051-x |
2023-02-01 | The aerospace industry relies heavily on lithium-ion batteries in instrumentation such as satellites and land rovers. This equipment is exposed to extremely low temperatures in space or on the Martian surface. The extremely low temperatures affect the discharge characteristics of the battery and decrease its available working capacity. Various solvents, cosolvents, additives, and salts have been researched to fine tune the conductivity, solvation, and solid-electrolyte interface forming properties of the electrolytes. Several different resistive phenomena have been investigated to precisely determine the most limiting steps during charge and discharge at low temperatures. Longer mission lifespans as well as self-reliance on the chemistry are now highly desirable to allow low temperature performance rather than rely on external heating components. As Martian rovers are equipped with greater instrumentation and demands for greater energy storage rise, new materials also need to be adopted involving next generation lithium-ion chemistry to increase available capacity. With these objectives in mind, tailoring of the electrolyte with higher-capacity materials such as lithium metal and silicon anodes at low temperatures is of high priority. This review paper highlights the progression of electrolyte research for low temperature performance of lithium-ion batteries over the previous several decades. | A review on the development of electrolytes for lithium-based batteries for low temperature applications | 10.1007/s11708-022-0853-5 |
2023-02-01 | The deformation behavior of an ultra-high strength low alloy steel (commercial name: XF1700) at strain rates 0.001/s, 0.1/s (quasi-static), 922/s, 5962/s, 6000/s (dynamic) and temperatures 25, 100, 200 and 400 °C by using Split-Hopkinson pressure bar (SHPB) compression test have been investigated in the presented work. The results revealed that at 400 °C temperature and 6000/s strain rate, the work hardening remains dominant over thermal softening and could be tracked through sample surface which exhibited fractures but didn’t lead to failure of sample. Elaborating this deformation behavior, a modified Johnson–Cook (JC) model for elastic–plastic behavior aided by Z parameter had been formulated based on the combined effect of strain and temperature. Furthermore, SEM images of SHPB samples divulged that at different temperatures (100, 200 and 400 °C) and 6000/s strain rate, different modes of plastic deformation like slip, twinning and shear bands are operative accordingly however, at 400 °C adiabatic temperature rise enabled the occurrence of adiabatic shear bands only. These adiabatic shear bands led to crack initiation and propagation but not failure, thus supporting the role of adiabatic temperature rise. By data comparison of predicted values obtained from modified JC model (MJC) and values from original JC model (OJC) with experimental values, MJC was found to be in better agreement with experimental values than OJC. The overall R value for MJC model is 0.9925 and for OJC is 0.9937, whereas, AARE% for MJC model is 2.33% and for OJC model is 5.27%. | Constitutive Analysis on Deformation Behavior of XF1700 Ultra-high Strength Low Alloy Steel in Perceptive of Adiabatic Temperature Rise and Strain | 10.1007/s11665-022-07237-x |
2023-02-01 | Low-cost thermal insulation porous ceramics with uniform pore diameter and low bulk density were prepared with soda-ash dregs and felsic tailings. We investigated the effect of temperature, foaming agent, fluxing agent, Al 2 O 3 and CaO content on the pore structure and crystal phase of porous ceramics. The effect of Ca 2+ in soda-ash dregs on the preparation of quartz-feldspar based porous ceramics was studied. The results showed that the contribution of Ca 2+ to the preparation of porous ceramics in this system was mainly to accelerate the Si-O bond fracture and reduce the sintering temperature at the initial stage of sintering, which destroyed the needle-like feldspar in the high temperature melt and reduced the melt viscosity, thus reduced the foaming resistance and promoted the porous products with uniform pore size distribution. The Ca 2+ content on the high side can participate in the formation of crystals in sintering. The generated needle-like diopside and augite, which have small length-diameter ratio, will negligibly change in the viscosity of melt at high temperatures, and their inhibition effect on pores is not as good as that of feldspar with large length-diameter ratio, resulting in the merger and collapse of pores. But the increase of diopside and augite can improve the compressive strength of porous products to some extent. Porous ceramic products containing needle-like feldspar phase can be prepared by using two kinds of solid waste, which can improve the compressive strength of the products and reduce the raw material cost and energy consumption while comprehensively utilizing the double solid waste. The optimal product has a bulk density of 0.45 g/cm 3 , a compressive strength of 3.17 MPa, and a thermal conductivity of 0.11 W/(m·K). | Preparation of Thermal Insulation Ceramics Using Felsic Tailings as Main Raw Material and Soda-ash Dregs as Flux | 10.1007/s11595-023-2664-1 |
2023-02-01 | The Canary Archipelago comprises seven volcanic islands formed by the activity of the Canary mantle anomaly that might have been caused by an ascending plume at the NW-African passive margin. The “Basal Complex (BC)”, which contains the islands pre-shield rock formations, is exposed in the northwest and central Fuerteventura and NW-La Gomera and preserves the archive of giant landslides that caused the removal of most of the shield-stage volcanic rocks. Tools, like low-temperature thermochronology (LTT) are sensitive to rapid cooling activities that accompany landslides. In addition, integrating LTT data with time–temperature ( t – T ) numerical modelling are a powerful tool for reconstructing the thermo-tectonic evolution as well as defining and quantifying long-term landscape evolution in a variety of geological settings. To unravel part of the long-term landscape evolution of Fuerteventura and La Gomera, zircon and apatite fission-track, and (U–Th)/He data combined with t – T numerical modelling were applied to 39 samples representing the main rock units of the BCs and younger magmatic rocks on both islands. In Fuerteventura, the Northwest and Central Basal Complexes reveal rapid cooling/exhumation of more than 200 °C at ~ 20 Ma. The quantification of the thickness of the rock column using the t – T cooling path would need the knowledge of the palaeo-heat flow. The published thickness of the moved rock column in Fuerteventura and La Gomera does not point to an extreme high heat flow. Therefore, the formation of a giant landslide leads to the removal of ~ 2.0 (± 0.5) km of the volcano rock column. Offshore, such a landslide has led to part of the Puerto Rosario large debris avalanche. The “Central Basal Complex” revealed two more rapid cooling/exhumation events at ~ 16 Ma and ~ 14 Ma that might also be related to landslides. The three landslides might be responsible for the formation of the nowadays Puerto Rosario Debris Avalanche Unit offshore. What might have caused the landslides in Fuerteventura. Age data published provide evidence for magmatic and tectonic activity that occur at the time of the formation of the giant landslides. In addition, the Miocene climate significant changes lead to changes in precipitation, and such changes might also provide a destabilisation of pyroclastic units. Therefore, the causes of the giant landslides might be related to more than only one process. The La Gomera BC has experienced two rapid cooling/exhumation events: the first at ~ 9 Ma, which might have caused ~ 2.0 (± 0.2) km of erosion forming the offshore Tazo avalanche, also known as the Tazo landslide. The second rapid cooling at ~ 8.0 Ma is located at the northwest of the Island and might have been caused by the Garajonay caldera collapse and followed by landslides. The landslides are assumed to have formed the Segments I, II, III, and VIII of the submarine debris avalanches offshore. Like Fuerteventura, both landslides might have been triggered by tectonic and magmatic activities as well as due to variation in precipitation caused by climate variation. | Timing of rapid cooling and erosional decay of two volcanic islands of the Canary Archipelago: implications from low-temperature thermochronology | 10.1007/s00531-022-02253-7 |
2023-02-01 | A high-entropy dual-phase AlTiVCoNi alloy with a low density of ∼6.24 g cm −3 is developed, and it consists of a hierarchical structure, including an ordered L2 1 phase, a disordered body-centered-cubic (BCC) solid-solution phase, and nano-sized L2 1 precipitates embedded in the BCC phase. It is found that this new alloy shows phase stability after the heat treatment at 1200°C for 24 h, and the compressive yield strength of this annealed alloy is approximately equal to that of the as-cast condition, ∼1.6 GPa. This alloy displays an exceptional compressive strength at room temperature and at 600°C, with the specific yield strengths of ∼261 and ∼210 MPa g −1 cm 3 , respectively. The semi-coherent interface of the L2 1 and the BCC phases makes the alloy phase stable and regulates the work-hardening mechanism. Local dynamic-recrystallization behavior and grain evolution are observed in the as-prepared alloy during compression at 800 and 1000°C, which results in the high-temperature softening. This alloy with a muti-phase hierarchical structure would provide a new paradigm for the development of next-generation low-density, high-entropy structural materials for high-temperature applications. 本文研究了一种新型低密度(~6.24 g cm −3 )双相AlTiVCoNi高熵合金, 其组织结构由有序L2 1 高熵金属间化合物、无序体心立方结构和纳米L2 1 相多层次结构构成. 该合金在1200°C + 24 h热处理下未发生相结构转变, 在此条件下具有优异的高温相结构稳定性, 其铸态和热处理态的压缩屈服强度相当, 达到~1.6 GPa. 另外, 该合金在室温和600°C条件下表现出了优异的强塑性匹配和优异的比屈服强度, 分别达到了约261和210 MPa g −1 cm 3 . 该合金的超高强度主要源于有序L2 1 相与体心立方相的半共格界面导致的一种强相结构稳定性和多层次结构的复合强化机制. 该合金在800和1000°C压缩过程中出现了动态再结晶软化,使得其高温强度有所降低. 这种“具有半共格界面L2 1 + 体心立方+ 纳米L2 1 颗粒”的多层次结构设计为开发新型低密度耐高温高熵合金提供了一种新设计思路. | A low-density high-entropy dual-phase alloy with hierarchical structure and exceptional specific yield strength | 10.1007/s40843-022-2178-x |
2023-02-01 | Visible transparent yet low infrared-emissivity (e) polymeric materials are highly anticipated in many applications, whereas the fabrication of which remains a formidable challenge. Herein, visible transparent, flexible, and low- ε polymeric films were fabricated by nanocoating decoration of indium tin oxide (ITO) and MXene on polyethylene terephthalate (PET) film surface through magnetron sputtering and spray coating, respectively. The obtained PET-ITO@MXene (PET-IM) film exhibits low ε of 24.7% and high visible transmittance exceeding 50%, endowing it with excellent visible transparent infrared stealthy by reducing human skin radiation temperature from 32 to 20.8 µC, and remarkable zero-energy passive radiative heating capability (5.7 µC). Meanwhile, the transparent low- ε PET-IM film has high solar absorptivity and electrical conductivity, enabling superior solar/electric to thermal conversion performance. Notably, the three heating modes of passive radiative and active solar/electric can be integrated together to cope with complex heating scenarios. These visible transparent low -ε polymeric films are highly promising in infrared stealth, building daylighting and thermal management, and personal precision heating. | Visible transparent, infrared stealthy polymeric films with nanocoating of ITO@MXene enable efficient passive radiative heating and solar/electric thermal conversion | 10.1007/s12274-022-4962-6 |
2023-02-01 | Abstract With the development of environmental monitoring, it is urgent to establish NO 2 sensor with good sensing performance. Compared with the traditional NO 2 sensors made of metal oxides, NO 2 sensors made of n-p heterostructure nanocomposites have good sensing performance in detection limit and operating temperature. ZnO nanoflake arrays with polyaniline film grown on the surface were prepared on ceramic tubes by hydrothermal and vapor diffusion method. The gas-phase diffusion method can control the heterostructure by adjusting the diffusion time. At room temperature (25 °C), the construction of rich n-p heterogeneous interface enables the sensor prepared by the nanocomposite to respond to NO 2 , showing the sensing performance with the response value of 28.00 to 10.00 × 10 –6 NO 2 ; the detection limit improved to 0.01 × 10 –6 and the recovery time of 18 s. In this work, the sensing mechanism of NO 2 at heterogeneous interface is analyzed, which provides a promising material for the detection of low concentration NO 2 at room temperature. Graphical abstract 随着环境监测需求的不断增加, 研制性能优异的二氧化氮传感器已迫在眉睫。与传统的金属氧化物NO 2 传感器相比, 具有n-p异质结构的纳米复合材料将在检测限和工作温度方面显示出更大的优势。本文采用水热法在陶瓷管上原位生长ZnO纳米片阵列, 并利用气相扩散法在ZnO阵列表面覆盖聚苯胺, 得到复合物薄膜, 并考察了聚苯胺扩散时间对气敏性能的影响。丰富n-p异质界面的ZnO/PANI复合材料传感器能够对NO 2 响应, 对10.00 × 10 -6 浓度的NO 2 响应值为28.00, 检测限为0.01 × 10 -6 , 恢复时间18 s。研究了NO 2 的敏感机理, 能在室温条件下检测低浓度NO 2 使ZnO/PANI成为气敏传感器的理想材料。 | ZnO/PANI nanoflake arrays sensor for ultra-low concentration and rapid detection of NO2 at room temperature | 10.1007/s12598-022-02149-0 |
2023-02-01 | Modified polyimides (MPIs) show great potential towards 5G communication applications, due to its excellent thermal stability, mechanical property and chemical stability as compared to most of polymers. Introducing fluoride groups or porous structure is favorable to ultra-low dielectric constant ( D k ) and dielectric loss ( D f ). However, the cost of the fluorinated MPIs is high and their synthetic processes are complicated, and porous MPIs suffer poor mechanical properties. Also, increasing the fraction of free volume is a very effective way to lower D k through introducing more ultra-low- D k air component. However, most of this kind of MPIs lag far behind the fluorinated MPIs and the porous MPIs in terms of ultra-low D f , hindering the application of MPIs in high-speed communication devices. Thus, it is highly desirable to develop intrinsic ultra-low- D k / D f MPIs at high frequency with less fluoric groups and nonporous structure. Herein, we introduce a facile and effective strategy to lower D k and D f through introducing rigid and large sterically hindered aromatic groups into MPIs. On the one hand, their large steric hindrance effect leads to low D k by increasing intrinsic free volume. On the other hand, the resulting highly stiff polymer chain and strong intermolecular interaction are favorable to reduce D f by inhibiting dipole orientations. Based on this strategy, the spirobifluorene groups are preferred. The as-prepared MPIs show excellent dielectric performance with low D k of 2.74–2.76 and low D f of 0.00599 at 10 GHz, to some extent, exceeding the multiple fluorinated MPI with D k / D f of 2.67/0.00663 at 10 GHz. | A Facile Strategy for Intrinsic Low-Dk and Low-Df Polyimides Enabled by Spirobifluorene Groups | 10.1007/s10118-022-2824-z |
2023-02-01 | Silicon has been irreplaceable for a long time due to its well-estiblished design and fabrication in the field of Micro-Electro-Mechanical System (MEMS). However, it has poor tribological properties, which limits the further application of actuators (with relative motion) based MEMS. First, the amorphous silicon (a-Si) coatings were prepared on silicon substrates and high-speed steel (HSS) substrates by plasma enhanced chemical vapor deposition, and the relationships between mechanical properties and tribological performance were also systematically discussed. The wear rate of a-Si film on HSS has decreased significantly (decreased by 81.55%) compared with a-Si coating on silicon, which can be attributed to the larger elastic modulus and hardness of a-Si on the HSS matrix. Then, tungsten disulfide (WS 2 ) nanoflake coatings with low interlayer shear stress were successfully prepared on the amorphous silicon (a-Si) coatings by the drop-casting method, forming a WS 2 + a-Si coating to enhance the tribological properties. Combined with first-principles simulations and the characterization of the wear scar morphology, the macro-scale sliding friction of this composite coating against the Al 2 O 3 ceramic ball was investigated in ambient air. The results indicated that the introduction of WS 2 nanoflakes reduces the coefficient of friction (CoF) from 0.5 to 0.08. The reduction in CoF could be attributed to the in-situ formation of WS 2 lubricating transfer film on the wear scar of the ball and the WS 2 heterogeneous interface on a-Si film, leading to asymmetric contact between the friction pairs, which in turn triggers low and stable friction. | A Comparative Study on the Anti-Friction Performance of Amorphous Silicon Films Enhanced by WS2 Nanoflakes | 10.1007/s12633-022-02110-x |
2023-02-01 | Phased small interfering RNAs (phasiRNAs) are abundantly expressed in anthers and linked to environment-related male fertility in grasses, yet how they function under different environmental conditions remains unclear. Here, we identified a rice ( Oryza sativa ) low temperature-induced Argonaute (AGO) protein, OsAGO1d, that is responsible for generating phasiRNAs and preserving male fertility at low temperature. Loss of OsAGO1d function causes low-temperature male sterility associated with delayed programmed cell death of tapetal cells during anther development. OsAGO1d binds miR2118 and miR2275 family members and triggers phasiRNA biogenesis; it also binds 21-nt phasiRNAs with a 5′ terminal U. In total, phasiRNAs from 972 loci are OsAGO1d-dependent. OsAGO1d protein moves from anther wall cells into meiocytes, where it loads miR2275 to produce 24-nt phasiRNAs. Together, our results show that OsAGO1d acts as a mobile signal to fine-tune phasiRNA production and this function is important for male fertility at low temperature. | Mobile ARGONAUTE 1d binds 22-nt miRNAs to generate phasiRNAs important for low-temperature male fertility in rice | 10.1007/s11427-022-2204-y |
2023-02-01 | A low-temperature bonding process using silver nanoparticles paste has been developed in air at temperatures of 150–250°C under 5 MPa. The resistivity and hardness of the sintered Ag layer significantly improved when the sample was isothermally annealed above 180°C. The microstructural evolution in the Ag nanoparticles paste at various bonding temperatures has been characterized, and their corresponding bonding strength analyzed. The results revealed that the joints can be successfully bonded at the lowest temperature of 150°C for 1 h and at 180°C for 10 min. No damage was found at the bonded interface after shear tests. In addition, thermal cycle tests were performed, and the microstructure evolution of the joints remained the same after the thermal cycle tests. | Low-Temperature Bonding Process by Silver Nanoparticles Paste for Power Electronic Devices | 10.1007/s11664-022-10118-7 |
2023-02-01 | Freshwater supply is declining in the context of climate change, pollution, and soil salinization, calling for sustainable methods to produce drinking water. For instance, salt water can be converted into pure water by steam generation. Interfacial solar steam generation involves photoabsorbers consisting of a photothermal material with broad solar absorption and a porous substrate with a thermal insulating character. Nonetheless, scaling up of classical devices for interfacial solar steam generation is actually limited by cost, biofilm formation, salt fouling, complicated fabrication processes, and toxicity. Alternatively, wood-based devices are cheap, biodegradable, abundant, and display high fluxes of evaporation compared with other nonbiodegradable photoabsorbers. Here we review the design and applications of wood-based solar steam generation devices, with focus on wood structure and properties, different types of devices, and factors controlling the evaporative performance. | Interfacial solar steam generation by wood-based devices to produce drinking water: a review | 10.1007/s10311-022-01501-1 |
2023-02-01 | In general, Sn-Ag-Cu solder is widely used for interconnections in semiconductor device packaging. However, recently, several factors have been considered to implement low-melting-temperature solder (LTS), which has a lower assembly temperature than conventional Sn-Ag-Cu solder material. Implementation of LTS solder though has a different driving force per each industry sector. Consumer electronics have a driving force for lower energy consummation towards a carbon net zero strategy compared to the high-performance chip industry sector, which has a different reason based on larger component size-induced challenges, like dynamic warpage. This is a deformation of printed circuit board (PCB) and package components during the reflow process by elevated temperatures. The behavior of dynamic component changes the package size, material characteristics, and temperature range. Although most of the LTS are based on the low-melting-temperature range of 130–140°C, a separate category of intermediate LTS is formed at around 180–190°C to target an assembly peak temperature of 200–210°C. The study presented here targets a LTS at an intermediate temperature assembly to avoid the most active dynamic warpage temperature region. LTS has significant benefits with less warpage and thermal damage towards the component and assembled board, due to the low reflow peak temperature. To improve the thermal cycling performance by maintaining a low melting temperature, a small amount of indium is used as a microalloy element, with 12 mm × 12 mm ball grid array components on 62-mil-thick boards thermal cycled from − 40°C to 125°C with Sn-based LTS including In and Bi. The microstructure changes during thermal cycling have been observed and electron-backscattered diffraction has been used to find a correlation between crack propagation and localized recrystallization. It was found that the added indium enhanced the thermal cycling performance compared to conventional Sn-Ag-Cu-based solders. To compare the paste-induced composition change which dilutes the indium-containing solder ball, a flux-only assembly has been compared. | Intermediate Low-Melting-Temperature Solder Thermal Cycling Enhancement Using Bismuth and Indium Microalloying | 10.1007/s11664-022-10121-y |
2023-02-01 | Low alloy steels are widely used in bridges, construction, chemical and various equipment and metal components due to their low cost and excellent mechanical strength. Information in the literature related to the preparation, advantages and disadvantages, and applications along with research progress of various types of protective coatings suitable for low-alloy steel surfaces is reviewed, while a conclusive and comparative analysis is also afforded to the numerous factors influencing the protective ability of coatings. The characteristics of coatings drawn from the latest published literature are discussed and suggest that the modification of traditional metal coatings and the development of new organic coatings under the consideration of environmental protection, low cost, simplicity and large-scale industrial application are simultaneously proceeding, which holds promise for improving the understanding of corrosion protection in related fields and helps to address some of the limitations identified with more conventional coating techniques. | Progress in corrosion-resistant coatings on surface of low alloy steel | 10.1007/s42243-022-00872-7 |
2023-02-01 | It is difficult to test the engineering properties of undisturbed cohesionless coarse-grained fillers in the laboratory, especially those with low water contents because most sampling methods disturb the natural structure of the filler. This study proposes a novel sampling method that uses menthol as a temporary cement to obtain samples that are more resistant to disturbance. Liquid menthol infiltrates the interparticle spaces and cements the particles together as it cools, forming a high-strength structure. The samples can then be cut with a cutting ring (for grain sizes ≤ 0.5 mm) or a cutting machine (for grain sizes > 0.5 mm) to prepare the final samples, from which the menthol is removed by heating. To demonstrate the feasibility of the method, a number of laboratory experiments were performed, including sampling tests, confined compressive strength tests, vibration tests, drop tests, and CT scans. The optimal particle temperature for introducing the liquid menthol is 70°C, while 90°C is optimal for removing the cemented menthol. For both cost and anti-disturbance reasons, 20°C is suggested as a suitable storage temperature for menthol-cemented samples. The interspace structure undergoes less change with increases in sample depth and with larger grain sizes. We recommend that the lower two-third of the depth of a menthol-cemented block is used as the final sample for laboratory testing. | A Novel Menthol-Cementing Sampling Technique for Cohesionless Coarse-Grained Fillers | 10.1007/s12205-022-0103-8 |
2023-02-01 | To investigate the influence of induction treatment on the pitting corrosion resistance of non-standard low-Ni high-Mn-N duplex stainless steel (DSS) coating, the DSS coating with different percentage of Mn and Cr was prepared by tungsten inert gas welding. The electrochemical and pitting corrosion tests were carried out to characterize the pitting corrosion resistance of the DSS coating. The results showed that, after the DSS coating was induction-treated, the ferrite-to-austenite ratio increased and the film thickness was reduced. The electrochemical performance of the DSS coating was severely deteriorated after the 960 °C induction treatment, leading to a decrease in the pitting corrosion resistance. The 1130 °C induction-treated DSS coating had better polarization resistance than the 960 and 1030 °C induction-treated DSS coating due to the slower heating rate in the induction treatment. The present work verified that Cl − exhibited a deteriorative effect on the pitting corrosion resistance of the DSS coating. Graphical Abstract | Influence of Induction Treatment on the Pitting Corrosion Resistance of Non-standard Low-Ni High-Mn-N Duplex Stainless Steel Coating | 10.1007/s11665-022-07184-7 |
2023-02-01 | Reducing the low-frequency loss (≤ 1 kHz) of the soft magnetic powder cores (SMPCs) while maintaining high saturation magnetic induction ( B s ) is beneficial to the high efficiency and energy saving of motor applications. Herein, the effects of silicone resin content (SI), compaction pressure, and annealing temperature on the magnetic softness, microstructure, and magnetic domains of Fe-6.5 wt.%Si SMPCs were systematically studied. The SMPCs with 1 wt.% SI content and pressed at 1800 MPa not only have good forming ability but also exhibit low total loss and high B s . According to the loss separation at 1 T and 1 kHz, the hysteresis loss accounts for more than 75% of the total loss. Annealing at 850 °C induces dense and large recrystallized grains with large-angle grain boundaries and easily mobile domain walls, resulting in low hysteresis and total loss. A higher temperature of 950 °C damages the cladding layer and causes direct powder-to-powder contact, which thus slightly increases hysteresis and eddy loss. The correlation between the core loss, microstructure, and magnetic domain provides a reference for the development of high- B s and low-loss SMPCs for high-efficiency motors. | Correlation Mechanism of Microstructure, Magnetic Domain, and Magnetic Softness of Fe-6.5 wt.%Si Composites with High Saturation | 10.1007/s10948-023-06519-2 |
2023-02-01 | By means of low-field nuclear magnetic resonance (LF-NMR), the transverse relaxation time ( T 2 ) signals of physically bound water in cement paste were monitored to indicate water content change and characterize the early-age hydration process. With the curves of the T 2 signals and hydration time obtained, the hydration process could be divided into four typical periods using the null points of the second derivative curve, and the influences of water-cement ratio ( w / c ) and hydration heat regulating materials (HHRM) on hydration process were analyzed. The experimental results showed that the hydration rate of pure cement paste in accelerated period presented a positive correlation with w/c . Compared to pure cement paste, the addition of HHRM extended all four periods, and led to a much faster hydration rate in initial period as well as a slower rate in accelerated period. Finally, according to the LF-NMR test results, the early-age hydration model of cementitious materials was proposed considering w/c and HHRM content. | Effects of Water-cement Ratio and Hydration Heat Regulating Materials on Hydration Process of Early-age Cementitious Materials | 10.1007/s11595-023-2671-2 |
2023-02-01 | Expanded polystyrene (XPS) is an important building exterior wall insulation material at present, and the investigation of fire behavior characteristics is an important way to solve the fire safety problem of XPS. In this study, the influence of low oxygen conditions and external radiation source on smoke and heat release characteristics of XPS are compared and investigated, and the fire spread characteristics of XPS under low oxygen conditions are also studied by investigating the characteristic parameters such as flame height, width, flame spread index and spread rate. The results indicate that the pyrolysis combustion of XPS is inhibited with the decreased oxygen concentration in the environment, resulting in reduced the ignition time and increased Smoke Produce Rate (SPR) peak. Moreover, the low oxygen condition has little effect on the heat release peak and total heat release of normal ignited materials due to the stable heat radiation source, but the heat release peak and total heat release is reduced greatly in the fire spread experiment. At the same time, there is a positive correlation between the heat release rate and the flame propagation index (FPI) under low oxygen conditions. This paper provides important data and theoretical support for the design and fire theory research of XPS. | The study of smoke, heat release and fire spread characteristics of expanded polystyrene under low oxygen condition | 10.1007/s10973-022-11788-5 |
2023-02-01 | Abstract The possibility of producing aluminum alloys during low-temperature electrolysis in cells with vertical low-consumption metal anodes and wetted cathodes is shown. Aluminum alloys are fabricated by electrolysis of KF–NaF (10 wt %)–AlF 3 –Al 2 O 3 melt with a certain cryolite ratio (CR) in a galvanostatic mode in cells with a vertically arranged Fe–Ni–Cu metal anode and a borated graphite cathode at 830°C. The electrolysis proceeds at a constant voltage of 2.8 ± 0.1 V for 14 h. The source of alloying components for aluminum alloys is the Fe–Ni–Cu metal anode, on the surface of which an oxide layer forms during electrolysis. The concentration of alloying metals in the resulting aluminum remains almost constant or increases slightly during electrolysis. To study the interaction of the oxide layer with the electrolyte components using isothermal saturation, we used the isothermal saturation method to determine the solubility of the Fe 2 O 3 and NiO oxides in low-melting potassium cryolite-based melts KF–AlF 3 and KF–NaF (10 wt %)–AlF 3 with a cryolite ratio CR = 1.3–1.5 in the temperature range 750–850°C. The solubility of Fe 2 O 3 in the cryolite melts decreases with increasing NaF concentration and decreasing CR. In the KF–NaF (10 wt %)–AlF 3 electrolyte with CR = 1.3, the solubility of Fe 2 O 3 is lowest (0.016 wt % at 820°C) among all the melts under study. At temperatures exceeding the corresponding liquidus temperatures by 30–90°C, the solubility of NiO in the low-melting cryolite melts is an order of magnitude lower than that of Fe 2 O 3 . | Electrolytic Production of Aluminum Alloys in Cells with a Low-Consumption Metal Anode and a Wettable Cathode | 10.1134/S0036029523020180 |
2023-02-01 | Two-phase closed thermosyphons (TPCTs) are widely used in many engineering systems. Various working fluids are used in TPCTs depending on the working conditions. One of these working fluids is R134a. However, R134a has high global warming potential (GWP) rate (1300). Therefore, many legal regulations (Montreal protocol, Kyoto protocol, United Nations Climate Change Framework Agreement (UNFCCC), etc.) have been made to diminish the influence of HFCs on the environment. Recently, R1234yf with a lower GWP ratio (4) was developed as an alternative to R134a and has been used in heat pump and vapor compression refrigeration systems. In this study, the use of R1234yf working fluid instead of R134a in a TPCT was theoretically and experimentally investigated. The energy and environmental impact analyses have been performed using the experimental data obtained from the study. It was seen that while the performances of R134a and R1234yf are close at 30 °C evaporator heating water temperature, the performance of R134a is higher than R1234yf at 35 °C, 40 °C, 45 °C, 50 °C evaporator heating water temperatures. Also, the total greenhouse gas emission of the R1234yf filled TPCT is 90.61% lower than the R134a filled TPCT. It was concluded that although the R1234yf has lower performance than that of R134a, R1234yf should be preferred as working fluid. Because R1234yf working fluid is highly effective in reducing greenhouse gas emissions of TPCT, a similar performance to R134a can be achieved by changing the design (number, size, orientation, fluid charge rate, etc.) of the TPCT filled with R1234yf working fluid. | Investigation of the two-phase closed thermosyphon filled with R1234yf alternative to R134a: energy and environmental analysis | 10.1007/s10973-022-11787-6 |
2023-02-01 | Grain boundaries (GBs), as a prevalent structural characteristic, play a crucial role in the deformation of nanoporous metals with nanosized grains and ligaments. However, the fundamental understanding of GB-mediated deformation is still lacking because the plastic behavior of discrete ligaments involving GBs remains to be unknown. Here, we report atomic scale visualizations of coupled GB dislocation climb and glide in nanoporous gold ligaments with low-angle GBs via in situ tensile straining inside a Cs-corrected transmission electron microscope. The zig-zag motion paths of GB dislocations are precisely determined by real-time tracking of the movements of dislocation cores. The concurrent climb and glide of the dislocation arrays are confined to a narrow GB region, greatly enhancing GB diffusion in the bicrystal ligament. Our findings of coupled dislocation climb and glide shine a light on the room-temperature deformation of nanoporous metals and provide a time-dependent atomic-level physical image for GB engineering. | Atomic scale visualizations of low-angle grain boundary mediated plasticity by coupled dislocation climb and glide in nanoporous gold | 10.1007/s12274-022-5306-2 |
2023-02-01 | The electrical resistances of Cu/Sn57BiSbNi/Ni solder joints were continuously monitored during current stressing at temperatures between 95 and 125°C, and current densities up to 7kA/cm 2 , for times approaching 3000 h. Scanning electron microscopy was utilized to characterize corresponding changes in solder joint microstructure. The statistics of failure based upon a 20% increase in electrical resistance (correlated with the growth of a continuous layer of Bi at the anode) were analyzed for groups of nominally identical samples, while either current density or temperature was independently varied. At longer times, after prodigious, diffusion-limited growth of a Cu 6 Sn 5 -based phase, catastrophic failure (an increase in electrical resistance of 20 mΩ) was observed and correlated with crack propagation across the width of the sample. The statistics of catastrophic failure were analyzed during current stressing of these SnBi-based solder joints at a relatively high temperature (125°C) and current density (4kA/cm 2 ). | The Failure of Sn-Bi-Based Solder Joints Due to Current Stressing | 10.1007/s11664-022-10086-y |
2023-02-01 | Here, we report a novel technique to stabilize selective laser-sintered silver–barium strontium titanate (Ag-BST) resistors at higher temperatures up to 250°C. We previously developed a Ag-BST printable convertible ink (insulating phase to conductive/resistive phase) to pattern resistive features on insulating Ag-BST films for printed electronics and additive manufacturing applications. The newly developed ultraviolet (UV) ink in this work is utilized to increase the temperature tolerance of selective laser-sintered Ag-BST resistors from 150 to 250°C. This temperature window is critical for most multi-step manufacturing processes as well as device operations. The combination of an acrylate-based bisphenol A monomer and boron nitride particles played a major role in the stabilization of Ag-BST by preventing the creation of additional conductive paths. The selective laser-sintered Ag-BST resistors which were protected with the novel UV ink showed less than 15% decreased resistance over 40 min of exposure at 250°C, demonstrating proof of concept for potential applications of this technique. This novel technique will increase the usage of Ag-BST in a wide range of printed electronics and other additive manufacturing applications. | Stabilizing Selective Laser-Sintered Silver–Barium Strontium Titanate (Ag-BST) Resistors Using a UV-Curable Ink | 10.1007/s11664-022-10049-3 |
2023-02-01 | Low-temperature bonding has become a significant trend in advanced electronics packaging technology. A low-reflow-temperature process can effectively reduce the risk of warpage, thus greatly enhancing device reliability. SnBi eutectic solder is one of the best candidates for low-temperature assembly. In this study, first, a layer of pre-solder (Sn-0.3Ag-0.7 Cu, SAC0307) was reflowed; then, another layer of low-temperature solder (Sn-56Bi-1Ag-0.2Cu, SB102) was reflowed on top to create a hybrid solder joint. Small bismuth precipitates were uniformly distributed in the SAC0307 layer after long-term aging. Cross-sectional images were examined to analyze the kinetics between the SB102/SAC interdiffusion reaction. Shear tests and fracture surface analyses were undertaken to investigate the joint strength and the failure mode. The SAC0307 layer prevented the solder embrittlement by reducing the ratio of Bi-rich phases in the SB102 matrix and successfully transformed the mechanical fracture mode from brittle to ductile. The results demonstrated that the mechanical properties of the solder joint were greatly improved after long-term heat treatment. | Hybrid Solder Joint for Low-Temperature Bonding Application | 10.1007/s11664-022-10111-0 |
2023-02-01 | The microstructure, tensile deformation, and texture evolution behaviors of Ti-Nb-Mo-Ce microalloyed high-strength weathering steels were studied under different deformation conditions. The effects of continuous dynamic recrystallization and deformation-induced ferrite transformation (DIFT) on the nanoprecipitation behavior and microstructure were analyzed and compared. The results demonstrated that austenite recrystallization zone rolling and isothermal treatments were combined to obtain the high-strength ferrite weathering steel comprising nanoprecipitates with a yield strength of 635 MPa, a tensile strength of 750 MPa, and a 21.2% elongation. Further, the non-recrystallization rolling in the austenite region benefitted the deformation-induced ferrite transformation, and the texture that was obtained under the DIFT microstructure conditions was mainly (110)[1-10]. Many ε-fiber textures, <110>//TD, appeared under the microtensile deformation condition, and the ς-fiber textures, <110>//ND, were weakened compared with those of the non-tensile deformation microstructure. Although the grains of the ferrite, which were prepared via rolling in the non-recrystallized region of the austenite, followed by the isothermal process, were finer, the size of their nanoprecipitates increased significantly and deteriorated the mechanical properties. | Effect of Deformation Temperature on Nanoprecipitates and Tensile Behavior of Ti-Nb-Mo-Ce Microalloyed Ferritic Steel | 10.1007/s11665-022-07235-z |
2023-02-01 | The a -axis grains and other secondary phase impurities, which are of great suppression for the superconducting properties, are easily formed on the surface of YBa 2 Cu 3 O 7-δ (YBCO)-coated conductors (CCs) prepared by trifluoroacetic acid metal organic deposition (TFA-MOD) method. Removal of these impurities is crucial to improve superconductivity and further applications. In this paper, low energy density argon ion etching method is proposed to modify the surface properties of YBCO films by removing the surface layer without damaging the epitaxial structure. It is an effective strategy to regulate the internal strain, oxygen content and Cu–O chains of YBCO films. It is demonstrated that the self-field critical current density ( J c ) of the ion etched samples can be enhanced compared with the pristine one via this surface treatment. Meanwhile, the etching time is a crucial parameter to modify J c values. | Improved Superconducting Performance of YBCO-Coated Conductors by Low Energy Density Argon Ion Etching | 10.1007/s10909-022-02856-z |
2023-02-01 | Understanding what environmental factors are genetically linked to a phenological event is critical for predicting responses to climate change. Photosynthetic phenology often varies among a species of evergreen conifers due to local adaptation. However, few empirical studies have revealed relevant relationships between climatic factors in provenance environments and photosynthetic phenology. This study evaluated the effects of environmental conditions of the growing site and seed source provenance on the seasonal changes in maximal photochemical quantum yield of photosystem II ( F v / F m ) in a common garden experiment with 2-year-old seedlings of Sakhalin fir ( Abies sachalinensis ), a representative species with local adaptation, from four seed source provenances. A logistic model was constructed to explain the seasonal variation of F v / F m from July to October and the relationships between the estimated model parameters and representative factors featuring provenance environments were evaluated. The landscape gradient of the detected model parameters responsible for the provenance environments was visualized in a map of the distribution area. The lowest temperature was the most plausible factor in the growing environment to explain the seasonal changes of F v / F m . Among the representative meteorological factors of provenance environments, the lowest temperatures in July showed significant relationships with two model parameters, explaining the lower limit of F v / F m and the higher sensitivity of autumn F v / F m decline. The estimated spatial maps of model parameters consistently showed that the higher the lowest temperature in July in the provenance environment, the lower the F v / F m in October and the greater the decrease in the autumn F v / F m decline. Therefore, the lowest summer temperature could be associated with the local adaptation of autumn photosynthetic phenology in A. sachalinensis. | Landscape gradient of autumn photosynthetic decline in Abies sachalinensis seedlings | 10.1007/s11676-022-01592-0 |
2023-02-01 | Untapped thermal energy, especially low-grade heat below 373 K from various sources, namely ambient, industries residual, and non-concentrated solar energy, is abundant and widely accessible. Despite that, there are huge constraints to recycle this valuable low-grade heat using the existing technologies due to the variability of thermal energy output and the small temperature difference between the heat source and environment. Here, a thermal-mechanical-electrical energy conversion (TMEc) system based on the Curie effect and the soft-contact rotary triboelectric nanogenerator (TENG) is developed to recycle thermal energy in the mid-low temperature range. According to the phase transition mechanism between ferromagnetic and paramagnetic, disk-shaped ferromagnetic materials can realize stable rotation under external magnetic and thermal fields, thus activating the operation of TENGs and realizing the conversion of thermal energy and electrical energy. During the steady rotation process, an open-circuit voltage ( V OC ) of 173 V and a short-circuit current ( I SC ) of 1.32 µA are measured. We finally obtained a maximum power of 4.45 mW in the actual working conditions, and it successfully charged different capacitors. This work provides a new method for mid-low temperature energy harvesting and thermal energy transformation and broadens the application of TENG in the field of thermal energy recovery. | Thermal-mechanical-electrical energy conversion system based on Curie effect and soft-contact rotary triboelectric nanogenerator | 10.1007/s12274-022-5056-1 |
2023-02-01 | In order to know the function of C 18:2 and C 18:3 fatty acids in the cold growth of the psychrotrophic yeast M. bicuspidata var. australis W7-5, the mutant 1 without C 18:2 fatty acid and the mutant 2 without C 18:3 fatty acids were obtained. Only the trace amount of C 18:2 fatty acid in the mutant 1 occurred while no C 18:3 fatty acid in the mutant 2 was detected. The growth rate of only the mutant 1 cultured at 5 ℃ and 25 ℃ was significantly reduced compared with that of the wild-type strain W7-5. But there was no difference between the growth of the mutant 2 and that of the W7-5 strain. These meant that only C 18:2 synthesized by the psychrotrophic yeast played an important role in cell growth at low temperature (5 °C) and high temperature (25 °C). Meanwhile, cell wall in the mutant 1 without C 18:2 fatty acid gown at 5 and 25 °C was also negatively affected, leading to the reduced cell growth rate of the mutant 1 grown at 5 and 25 °C. | Genome-Wide Editing Provides Insights into Role of Unsaturated fatty Acids in Low Temperature Growth of the Psychrotrophic Yeast Metschnikowia bicuspidata var. australis W7-5 | 10.1007/s10126-022-10182-4 |
2023-02-01 | We have developed a passive system to efficiently reduce the amplitude of temperature oscillations in low-frequency Pulse Tube (PT) cryocoolers. It consists of a small, well-insulated tank of liquid 4 He, placed between the cold head of the PT and the user. As a result, we have been able to reduce the amplitude of thermal oscillations by a factor of 192, from 173 mK to 0.9 mK. The same damping efficiency can be obtained even if a thermal power of up to 100 mW is dissipated over it: the temperature oscillations remain consistently small as long as the Helium remains in its liquid phase. Even after its transition to the gas phase, the thermal oscillations continue to be stable, and despite increasing in amplitude by one order of magnitude, reaching 9 mK, they remain 19 times lower than those at the cold head of the PT. The advantage of this tool resides in the fact that it is a small, very compact sealed Helium reservoir, free of moving parts and external links. | An Efficient Damper of Thermal Oscillations for Two-Stage Pulse Tube Cryocoolers | 10.1007/s10909-022-02931-5 |
2023-02-01 | The results of numerical and experimental studies of zirconium irradiated by a low-energy high-current electron beam with an energy density ranging from 2.2 to 5.2 J/cm 2 are presented. The dynamics of surface melting is simulated, and the thickness and lifetime of the melt, as well as the cooling rates achieved in zirconium during pulsed electron beam processing, are determined. The structure and properties of zirconium are experimentally studied, it is shown that as a result of processing, a martensitic α'-phase is formed in the layer quenched from the melt. It is established that the formation of the martensitic phase increases the surface nanohardness and wear resistance. The maximum value of the surface layer nanohardness obtained by the processing is twice higher than the initial value. | Changes in the Surface Structure and Properties of Zirconium Upon Exposure to a Low-Energy High-Current Electron Beam | 10.1007/s11182-023-02814-6 |
2023-02-01 | In this study, sodium lignosulfonate modified illite (LS-ILT), an environmentally friendly adsorbent, was prepared by hydrothermal modification. An extensive study of Pb(II) and Cd(II) adsorption behavior and the mechanisms were conducted by evaluating the effects of initial pH value, sorbents dosage, and initial concentration of Pb(II) and Cd(II). Results showed that the adsorption characteristics of Pb(II) and Cd(II) by LS-ILT were well described by quasi-second-order kinetics and the Freundlich model, and the maximum adsorption capacity of Pb(II) and Cd(II) was 42.3 mg/g and 17.0 mg/g, respectively. The optimal application conditions for adsorption equilibrium were the dosage of 4 g/L and reaction pH = 5.5–5.8. The adsorption stability of Pb(II) by LS-ILT was better than that of Cd(II), and most of the existence of coexisting cations had no obvious inhibitory effect on the removal of Pb(II) and Cd(II). Furthermore, the dynamic adsorption results showed that LS-ILT can meet the ultra-low emission standard, and the adsorption capacity could maintain over 50% after four cycles, further providing certain guiding significance for the treatment of wastewater with ultra-low concentrations of heavy metals Pb(II) and Cd(II). | Highly efficient preferential adsorption of Pb(II) and Cd(II) from aqueous solution using sodium lignosulfonate modified illite | 10.1007/s11356-022-23807-x |
2023-02-01 | The intensified indoor living during the spring 2020 lockdown, with enhanced user awareness of the prevailing conditions in their homes, constituted a natural stress test for the housing design in place today. Surveys conducted during this period have yielded lessons for designing better intervention strategies for the residential sector, taking into account the systematic morphological and economic limitations of the buildings concerned. These considerations should inform the development of policies and strategies for improving environmental quality compatible with lower residential energy consumption and higher quality of life. This study explores the effect of occupant behaviour on home ventilation and the perception of the impact of indoor air quality on user health before and during lockdown. The method deployed consisted in monitoring environmental variables and conducting user surveys before and after restrictions came into force. The findings showed that prior to lockdown, occupants were unaware of or paid little heed to changes in indoor air quality, failed to perceive stuffiness, and, as a rule, reported symptoms or discomfort only at night during the summer months. During lockdown, however, users came to attach greater importance to air quality, and a greater sensitivity to odours and a heightened awareness of CO 2 concentration prompted them to ventilate their homes more frequently. In the spring of 2020, occupants also indicated a wider spectrum of indisposition, in particular in connection with sleep patterns. | Effects of covid-induced lockdown on inhabitants’ perception of indoor air quality in naturally ventilated homes | 10.1007/s11869-022-01239-3 |
2023-02-01 | FeSiCr/MnZn ferrite composites with low permittivity were prepared by a two-step synthesis method, which can improve the absorbing property of the material. The phase and thermal behavior of the composites were analyzed by x-ray diffractometry, thermogravimetric analysis/differential scanning calorimetry. The morphology was studied by scanning electron microscopy. The soft magnetic properties and electromagnetic parameters of the material were tested by a vibrating sample magnetometer and a vector network analyzer. The results show that, compared with pure FeSiCr powders, the complex permittivity of a FeSiCr/MnZn ferrite composite was significantly decreased, while the complex permeability was slightly decreased, achieving a more ideal impedance matching. When the MnZn ferrite content is 15% and the simulated thickness is 2 mm, the minimum reflection loss (RL) of the sample reached − 27.4 dB at 10.4 GHz, and the bandwidth reached 5.0 GHz when RL exceeded − 10 dB. Graphical Abstract | Microwave Absorption Properties of FeSiCr/MnZn Ferrite Composites Prepared by Two-Step Synthesis | 10.1007/s11664-022-10156-1 |
2023-02-01 | A microwave absorbing sheet with a high complex permeability and a relatively low complex permittivity is obtained by molding of the densely coated flaky carbonyl iron particles (FCIPs) by styrenebutadiene-styrene block copolymer (SBS) in the assistance of coupling agent modification. Direct molding of the core-shell FCIPs without adding extra binder results in a large permeability due to the high filling ratio (55 vol%) of absorbents. Importantly, the permittivity is well suppressed by the dense insulate polymer shell on the FCIPs, avoiding the severe impedance mismatch problem of the high filler content microwave absorbing materials. Investigations show that modifying the surface of FCIPs by proper amount of silane coupling agent is critical for the coating quality of the SBS shell, which is verified by resistivity and corrosion current density measurements, and can be interpreted by improved interfacial compatibility between the modified FCIPs and SBS. The obtained microwave absorbing sheet shows a minimum reflection loss of −38.74 dB at 1.57 GHz and has an effective absorption bandwidth from 1.1 to 2.3 GHz at a relatively small thickness of 2 mm. | Enhanced Microwave Absorption for High Filler Content Composite Molded from Polymer Coated Flaky Carbonyl Irons Modified by Silane Coupling Agents | 10.1007/s11595-023-2665-0 |
2023-02-01 | In this work, 6-mm-thick ASTM A387-11–2 steel plates have been butt welded at optimized parametric settings of current (A) = 100 A, voltage (V) = 13 V, and gas flow rate (GFR) = 21 L/min. The as-welded plates have been visually inspected for any surface defects and were found to be defect-free. Further, the weldments were subjected to macroscopic metallography to explore the weld bead geometry. Macroscopic results reveal that the RMD process produces a higher depth of penetration (DOP) and lower heat-affected zone (HAZ) as compared to the GMAW process. Optical and scanning electron microscopy have also been done to examine the internal microstructure in the weldments. The result of microscopic analysis reveals the presence of pearlite and ferrite in the base metal. The process of grain refinement in the heat-affected zone and weld zone was also observed in the form of fine-grain particles which confirms the presence of martensite in the weld zone. In addition to this, the microhardness values for both weldments were measured and compared. The microhardness of GMA weldments was found to be too high in all the zones as compared to that of RMD weldments and hence gives the affirmation with the obtained microstructures in the welded samples. | Influence of Regulated Metal Deposition and Gas Metal Arc Welding on ASTM A387-11–2 Steel Plates: As-deposited Inspection, Microstructure, and Mechanical Properties | 10.1007/s11665-022-07185-6 |
2023-02-01 | Over the past decades, low flow has been highly impacted by climate change across Turkey, and it is important to investigate low flow trends and drivers of this change to guide water resources management. The standard normal homogeneity test (SNHT), the Pettitt test, and the Buishand range test were used for homogeneity analysis. A comprehensive assessment of trends and variability in low flows from 88 flow stations located in 26 river basins across Turkey and their attributions in a changing climate were presented. The Mann–Kendall (MK) and modified Mann–Kendall test (mMK) were utilized to detect the significance of trends, while Sen’s slope method was used to identify the magnitude of trends. According to the trend test results, the low flow records of 34 stations indicated statistically decreasing trends, whereas those of four stations indicated a statistically increasing trend. We also analyzed how climate variables affect low flow variations. Correlations between climate variables (temperature and precipitation) and large-scale climate models with low flow were determined by Spearman's Rho test. North Atlantic Oscillation (NAO), Western Mediterranean Oscillation (WeMO), Southern Oscillation Index (SOI), and Pacific Decadal Oscillation (PDO) were investigated for their relation with the low flow variability. The results showed that low flow data were generally positively correlated with precipitation, and this result was particularly pronounced on the annual scale. Unlike precipitation, low flow series have a negative correlation with temperature data, and correlations are clearer during dry periods. In most areas, NAO and SO were negatively correlated with low flow patterns in Turkey, while PDO and WeMO were positively correlated with low flow series. The results indicate that low flows in most regions are more sensitive to precipitation than temperature and large-scale climate models. In addition, this research reported that the use of seasonal indices made some seasonal correlations more pronounced than their annual counterparts. These results suggest that seasonal climate indices can be potential candidates for low flow prediction. | Assessing the main drivers of low flow series in Turkey | 10.1007/s11069-022-05621-3 |
2023-02-01 | Current petroleum issues, quickly raising its costs and uncertainties regarding petroleum fuels availability endanger the renewable and sustainable challenge of the worldwide economy. Both the ecological consideration and availableness of fuels highly impact fuel directions for transport vehicles. The current paper introduces the Prospects for producing hydrotreated vegetable oil (HVO) and fatty acid methyl esters (FAME) biodiesel fuels and their applications. The potential of raw material supply for the production biodiesel in Russia was examined, including sunflower oil, soybean oil, rapeseed oil, tall oil, and used cooking oil. Additionally, an economic evaluation of biodiesel production in Russia was performed. Likewise, Russia has launched the process of developing low-carbon strategies for the energy transition, but the country is placing more emphasis on the electrification and gasification of transport. The results reported that HVO is a promising low-carbon component of biological nature than FAME, according to it has a high calorific value, and great chemical stability. Furthermore, the results indicated that the most promising feedstock for biodiesel production in Russia is rapeseed oil, as rapeseed retains a higher yield growth potential. Finally, the most preferable option is the hydroprocessing of oils in a separate unit with a capacity of 500,000 tons/year for oil. Large capacity is probably redundant given the limited resources of advanced raw materials up to 100–150,000 tons of waste oils and up to 150–200,000 tons of tall oils. Graphical abstract | Current Challenge and Innovative Progress for Producing HVO and FAME Biodiesel Fuels and Their Applications | 10.1007/s12649-022-01880-0 |
2023-02-01 | Using double-pulsed melt inert-gas welding (DP-MIG)-based wire arc additive manufacturing (WAAM), the 2319 aluminum alloy components were fabricated with different pulse frequencies. The low-frequency pulses with 1, 3 and 5 Hz were used to deposit thin-wall parts. The scanning electron microscopy (SEM) and optical microscopy (OM) were used to observe the microstructure and fracture surface; the EDS was performed to identify the precipitation phase. The tensile properties were carried out along vertical direction and horizontal direction. The results show that the θ and θ ′ phases were found in the deposition part. As the low frequency increases, the equiaxed size in the inner layer region decreases and promoted the precipitation of the θ phase. By changing the low-frequency pulse from 1 to 3 Hz, the ultimate tensile strengths and the elongations in the horizontal as well as vertical the directions increase by 25.67, 19.46 MPa, 0.36 and 4.59%, respectively. The maximum tensile strength reached 253.18 MPa when the pulse frequency was 3 Hz. A large number of dimples were observed on the fracture surface for different pulse frequencies, indicating that the fracture modes of different frequencies were mainly ductile fracture. | The Microstructure and Mechanical Properties of High-Strength 2319 Aluminum Alloys Fabricated by Wire Double-Pulsed Metal Inert Gas Arc Additive Manufacturing | 10.1007/s11665-022-07209-1 |
2023-02-01 | Abstract This article presents the results of examining pilot bainite steel railroad rails and their tests. It is shown that the set of properties typical of these rails is unreachable in standard perlite steel rails and includes a combination of high strength, hardness, ductility, and impact toughness. Bainite steel rails exhibit a better resistance to fatigue defect formation and a greater fracture toughness and, at the same time, increased contact-fatigue strength and reliability at low temperatures. Considering the demand for rails designed for use at high loads, complex track plan, and low temperatures on the railroads of the Eastern Testing Area and Northern Latitudinal Railway, bainite steel seems an expedient alloy for application. | Prospects of Making Bainite Steel Rails | 10.3103/S0967091223020043 |
2023-02-01 | Silica/resorcinol–formaldehyde (RF) hybrid xerogels with low shrinkage were prepared efficiently in an environmental-friendly way through a two-step method and ambient drying process. Poly(diallyldimethylammonium chloride) (PDADMAC) was used as a soft template, aqueous solution of resorcinol and formaldehyde was used as organic source, and hydrosol of tetraethoxysilane and methyltriethoxysilane was used as inorganic source. Then, the hybrid xerogel sample was grafted with trimethylchlorosilane to improve its hydrophobicity. By adjusting the amount of PDADMAC, the minimum shrinkage can be controlled at about 2%. With the slight increase of pH from 2.13 to 2.98, the average pore size decreased sharply from 24.82 to 0.47 μm, and the specific surface area increased significantly from 0.63 to 26.51 m 2 /g, but it still maintained the characteristics of low shrinkage (1.16–2.18%), low density (0.20–0.25 cm 3 /g) and high porosity (~ 80%). Scanning electron microscopy (SEM) analysis showed that the polysiloxane formed a continuous coating on the surface of the RF resin skeleton, and the average particle size decreased from micron level to nanometer level. Mechanics testing indicated that its elastic modulus is as high as 37.26 MPa. Thermogravimetric analysis in air revealed that the weight loss rate of hybrid modified samples slowed down at the high-temperature range (200–600 °C), and the residual weight increased from 0.65 to 13.80% at 800 °C. The water contact angle test before and after hydrophobic modification demonstrated that the contact angle increased sharply from 0° (superhydrophobic) to 160° (superhydrophobic). | Facile, tunable, and environmental friendly synthesis of silica/resorcinol–formaldehyde hybrid xerogels with ultra-low shrinkage using a cationic polyelectrolyte as a soft template | 10.1007/s10934-022-01301-6 |
2023-02-01 | Abstract The effect of water on double and triple polyethylene (PE)–polylactide (PLA) blends of various compositions, including those with the addition of aged polyethylene as an analog of recycled polymer is studied in this paper. It is established that the composition of the blends directly affects its characteristics, especially when exposed to water as an aggressive factor. PE–PLA composites have a maximum degree of water absorption of about 7.5%, and in the presence of the third component, oxidized polyethylene in the amount of 40 and 50 wt %, the degree of water absorption increases to 10%. It is shown by IR spectroscopy that after the action of water, structural elements belonging to PLA are destroyed, which is due to the more active interaction of water molecules with PLA molecules, while the characteristics of the polyethylene matrix remain practically unchanged. | Effect of Water on the Structure of Polyethylene–Polylactide Binary Blends and Polyethylene–Polylactide–Aged Polyethylene Ternary Blends | 10.1134/S1990793123010098 |
2023-02-01 | The purpose of this study is to determine whether piston friction can be reduced by applying a micro-pattern to the skirt portion of the piston, which accounts for the largest proportion of engine parts. The roughness of the ready-made pistons was reduced before etching the micro-scale pattern onto the piston skirt. The micro-patterns were screen-printed on the piston skirt, and kept uniform through etching. The friction reduction effect of the piston was confirmed through an engine experiment using a 1.6 L four-cylinder gasoline engine to remove parts. A hexagonal shape that is representative of bionic textures was selected for the micro-pattern, and circular and cross-hatch patterns were additionally produced for comparison. The friction experiments with the patterning pistons confirmed that friction was reduced by up to 6.74 % by adjusting the spacing of the hexagonal pattern. It was also confirmed that friction was reduced in the cross-hatch pattern by up to 5.28 %. The friction reduction effect may vary depending on the parameters used for a specific pattern. | Reduction of Piston Skirt Friction Using the Micro-scale Patterned Surface | 10.1007/s12239-023-0002-0 |
2023-02-01 | Cut-off lows are crucial extratropical circulation systems that can bring weather extremes over large areas, but the mechanism responsible for the life cycle of cut-off lows remains elusive. From a perspective of regional eddy-mean flow interaction, this study investigates the dynamical processes controlling the evolution of early-summer cut-off lows over Northeast Asia using the 6-hourly reanalysis data. Through the diagnostic of local wave activity (LWA) budget, we show that the cut-off low is initialized by a Rossby wave train originated from the subpolar North Atlantic, and then reinforced rapidly by zonal LWA flux convergence and local baroclinic eddy generation, and eventually decayed through energy dispersion by zonal wave activity advection. Furthermore, we show that the evolutions of the above dynamical processes are strongly modulated by the changes of background flow. In early summer, Northeast Asia is located at the eastern exit of the midlatitude jet to the north of the subtropical jet and exhibits a weak meridional gradient of potential vorticity, which favors frequent formation of cyclonic anomaly and energy accumulation. Prior to the onset of cut-off lows by several days, a Rossby wave train propagates along the Eurasian midlatitude jet, which initializes a cyclonic anomaly over Northeast Asia. With the aid of mean flow advection of anomalous zonal momentum, the zonal winds are then decelerated at the midlatitude jet exit and accelerated at the subtropical jet center. The former obstructs the wave packet proceeding downstream and the latter favors stronger baroclinic eddy generation below the subtropical jet. The two processes together maintain and strengthen the cyclonic anomaly in Northeast Asia rapidly. | Dynamical processes controlling the evolution of early-summer cut-off lows in Northeast Asia | 10.1007/s00382-022-06371-5 |
2023-02-01 | Here, well-dispersed and ordered ultrafine Pt nanocatalysts (Pt/SWCNTs) were synthesized by ice-photochemical method on single-walled carbon nanotubes (SWCNTs) without stabilizers and reducing agents. The catalytic performance of Pt/SWCNTs was studied in the reduction of 4 -nitrophenol ( 4 -NP). The morphology and crystal structure of as-synthesized materials were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The prepared samples all contained diffraction peaks of C and Pt with small size and good dispersion by XRD analysis. HR-TEM images displayed that the average particle sizes of the three samples were 1.2 ± 0.2 nm, 1.0 ± 0.2 nm and 1.1 ± 0.1 nm, respectively. The XPS analysis results confirmed the existence of Pt 0 . The catalytic performance test results showed that the prepared Pt/SWCNTs could effectively catalyze the reduction of 4 -NP to 4 -aminophenol ( 4 -AP) with the apparent rate constants of 0.36 min −1 , 0.28 min −1 , and 0.35 min −1 , respectively. Compared with literatures, they all had better catalytic activity. Though after seven cycles, the high catalytic activity was maintained with no significant deactivation and indicating high stability. The experimental results showed that Pt nano-rectangular array catalysts with uniform distribution and ultrasmall particle size were synthesized by a simple freezing method under the irradiation of visible (Vis)/ultraviolet (UV) light. It was demonstrated that the dispersion of Pt(II) reaction intermediates was effectively limited by light induction, carrier-substrate interaction and the use of the natural domain limitation of the ice lattice. Thus controlling the aggregation of Pt(0) to a certain extent and obtaining ordered dispersed ultrafine Pt nanoparticles. This method not only provides a method for the synthesis of ultrafine nanoparticles, but also provides a new idea for single-atom dispersed nanoparticles. Graphical Abstract | Photochemical Freeze Synthesis of Ultrafine Platinum Nanocatalysts | 10.1007/s10562-022-03976-7 |
2023-02-01 | Abstract An ethylene glycol (EG)–acetone (AC) system is studied via differential scanning calorimetry in the −140 to +40°С range of temperatures. A phase diagram is plotted over the range of concentrations. It is found that the mixtures in the system are supercooled by more than 30°C. Low-temperature melting is recorded in the region around −98°C, which corresponds to the eutectic point temperature. The devitrification of rapidly cooled samples is observed in the range of concentrations up to ~21 mol % AC, and the temperature of devitrification is determined ( T g ~ −120°C). The plotted phase diagram of the EG–AC system is compared to a water–acetone phase diagram. | Low-Temperature Phase Equilibria in an Ethylene Glycol–Acetone System | 10.1134/S0036024423020267 |
2023-02-01 | The present work examines the behavior of lime fly ash-treated recycled concrete aggregate (LFRCA) as a base course material for low-volume rural roads (LVRRs). The recycled concrete aggregate (RCA) material was stabilized with 10%, 15% and 20% LFA content with a lime-to-fly ash ratio of 1:2. Mechanical tests were carried out to determine the unconfined compressive strength (UCS), indirect diametrical tensile strength (IDTS) and durability. Microstructural analysis was also done using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffraction to confirm the stabilization process. The micro-level characteristics' findings attributed to the pozzolanic reaction between lime and fly ash. The test results demonstrated that adding 10–15% LFA content is sufficient to meet the strength and durability requirements of 3 MPa for stabilizing RCA. Finally, the pavement design was carried out using lime fly ash-stabilized recycled concrete aggregate (LFRCA) as a base course material, and the strains were determined using IIT PAVE software. The design and analysis indicated that the pavement with 215–250 mm thickness of LFRCA as the base layer for different traffic and subgrade conditions meets fatigue and rutting performance criteria. It has been noticed that the pavement thickness with LFRCA is comparable to that of pavement thickness with cement-stabilized base. This study provides an approach to the sustainable use of RCA and FA in pavement applications. | Strength and Durability Characteristics of Lime Fly Ash-Stabilized Recycled Concrete Aggregate for Use in Low-Volume Rural Roads | 10.1007/s40098-022-00659-3 |
2023-02-01 | A refractive index (RI) sensor has been demonstrated and numerically analyzed by the finite element method (FEM) to gain supreme sensitivity on the basis of localized surface plasmon resonance (LSPR). Plasmonic material, such as silver, has been used as a coating layer outside of the dielectric core. Various structural parameters have been analyzed for the proposed sensors, which have a significant influence on the sensing field. To make the sensing strength much stronger, a thin MgF2 layer has been added to the silver layer. The wavelength and amplitude interrogation method achieves extremely high wavelength sensitivity (WS) responses of 948.67 μm/RIU and amplitude sensitivity (AS) responses of − 1602.82 RIU −1 in the analyte RI range of 1.35 to 1.38. The operating wavelength range of 5.5–7.5 μm shows efficient results in this structure. The proposed sensor is used for identifying analytes in the biological and biochemical fields and is also applicable in bio-photonics. Owing to its low confinement losses and simply designed structure, the proposed RI sensor will be extensively appropriate for bio-sensing because of its outstanding sensitivity response. | Exploration of LSPR-based Refractive Index Sensor Coated with Silver-MgF2 Layer | 10.1007/s11468-022-01767-9 |
2023-02-01 | Abstract High moisture content affecting coal bed methane (CBM) occurrence and transport is a typical feature of low-rank coal (LRC). The mechanism of the influence of moisture on methane diffusion properties of LRC is critical to improve CBM production and prevent coal and gas outburst. In this paper, a new method was designed to prepare coal samples with different moisture contents (0–16.80%). The desorption experiment at different moisture contents was conducted to study the time-varying diffusion properties of selected LRC and medium-rank coal samples. Results show that with the moisture content increase, the desorption volume and the initial desorption rate of LRC decrease obviously. Based on the negative linear relationship between the initial diffusion coefficient ( D 0 ) and moisture content ( M ), a mathematical model between them is established, which can be described as D 0 = λM + D dry , where λ and D dry are the material constant and D 0 of the dry coal sample, respectively. Moreover, with the increase in moisture content, the time-varying diffusion coefficient ( D t ) and its decay rate decrease obviously. It indicates that moisture can significantly reduce the diffusion capacity of LRC, and the competitive adsorption between moisture and methane molecules is an important factor affecting the diffusion properties of LRC. It is worth noting that there is a critical value of moisture content, beyond which increasing moisture content has no significant effect on reducing desorption and diffusion capacity. Results can provide a theoretical basis for taking hydraulic technology to prevent outburst in LRC mining. Article Highlights (1) Moisture can significantly reduce methane desorption capacity of low-rank coal. (2) Effect of moisture on the time-varying diffusion properties of methane in low-rank coal was studied. (3) Mathematical model of methane initial diffusion coefficient and moisture was established. | Effect of Moisture on Time-Varying Diffusion Properties of Methane in Low-Rank Coal | 10.1007/s11242-022-01876-3 |
2023-02-01 | Abstract — A comprehensive study of the Upper Cambrian and Lower Ordovician rock complexes of Northern Kazakhstan was carried out; their ages were substantiated; the structural pattern and setting and rock compositions were investigated. It was established that the Upper Cambrian complexes are represented by coarse clastic sequences and mafic alkaline effusive rocks and gabbro, while felsic volcanic rocks and granites are represented only by boulders in conglomerates. The Lower Ordovician is characterized by basalt–rhyolite series, felsic alkaline volcanics, and granitoids. The lateral series of structures of the active continental margin were reconstructed for the Late Cambrian and the Early Ordovician. The Late Cambrian lateral series includes only the structures of the extensional hinterland, where rock complexes with intraplate-type geochemical characteristics were formed. The lateral series of the Early Ordovician structures represent the foreland volcanic region, where island arc-related volcanics are widespread, and the extensional hinterland region with intraplate felsic volcanic rocks and granites. It is assumed that the differences between the lateral series of structures could be due to a change in the sense of plate motion within the active continental margin at the Cambrian–Ordovician boundary, when the transform faulting mode, which is not associated with suprasubduction magmatism, gave way to the convergent magmatism with wide development of arc-related volcanic rocks. | Reconstruction of the Lateral Series of the Late Cambrian and Early Ordovician Active Continental Margin Structures in the Paleozoides of Northern Kazakhstan | 10.1134/S0016852123010041 |
2023-02-01 | The high cost, CO poisoning, and slow electro-oxidation kinetics of Pt-based noble metal catalysts limit the merchandizing of direct methanol fuel cell. Here, metal zeolite imidazole frameworks composites are used to acquire a small amount (6.5 wt%) of Pt nanoparticles modified molybdenum carbide-decorated metallic cobalt@nitrogen-doped carbon nanohybrid materials (Pt–Mo/Co@NC). Compared with the merchant Pt/C catalysts, the obtained Pt–Mo/Co@NC composites exhibit substantially enhanced electrocatalytic activity and stability, and the mass activity reaches 1727 mA mg −1 at − 0.1 V, which is about 4.3 times that of merchant Pt/C catalysts. | Multi-dimensional Pt–Mo/Co@NC nanocomposites with low platinum contents for methanol oxidation | 10.1007/s10008-022-05311-x |
2023-02-01 | Developing scintillators with high light yield (LY), superior irradiation stability, and weak afterglow is of significance for the realization of low-dose high-resolution X-ray excited optical luminescence (XEOL) imaging. Lanthanide doped fluoride nanoparticles possess low toxicity, superior environmental stability, facial fabrication process, and tunable emissions, which are appropriate candidates for the next generation nanoscintillators (NSs). However, the low LY and strong positive hysteresis greatly restrict their practical application. Here, we propose an effective strategy that engineers energy gap to significantly enhance the LY. Our results verify that the tetragonal LiLuF 4 host benefits the crystal level splitting of Tb 3+ ions, which greatly promotes the electrons population on the Tb 3+ : 5 D 4 level followed by the enhanced LY. The LY of LiLuF 4 :Tb@LiLuF 4 NSs is calculated to be ∼ 31,169 photons/MeV, which is much higher than the lead halide perovskite colloidal CsPbBr 3 (∼ 21,000 photons/MeV) and LuAG:Ce (∼ 22,000 photons/MeV) scintillators. Moreover, the positive hysteresis is remarkably restricted after coating a thin shell. The X-ray detection limit and spatial resolution are measured to be ∼ 21.27 nGy/s and ∼ 7.2 lp/mm, respectively. We further verify that this core/shell NS can be employed as scintillating screen to realize XEOL imaging under the low dose rate of 13.86 µGy/s. Our results provide an effective route to develop high performance NSs, which will promote great opportunities for the development of low-dose high-resolution XEOL imaging devices. | Enhancing light yield of Tb3+-doped fluoride nanoscintillator with restricted positive hysteresis for low-dose high-resolution X-ray imaging | 10.1007/s12274-022-4998-7 |
2023-02-01 | Abstract The optimum design geometry of a quasi-neutral plasma source is calculated. An ion-source scheme with the inductive plasma discharge induced and maintained by a rf electromagnetic field with a frequency of about 1 MHz is investigated . The surface profiles of the main design units, including the discharge chamber and electrodes of the ion-extraction system, are jointly optimized using computational modelling. The calculation is carried out within a previously developed engineering model of inductive discharge in plasma. The optimization criteria are the thrust and the ion current extracted from the source, which are determined from the calculated electron density and electron temperature distributions over the discharge-chamber volume. The optimization calculation is made for an ion source 16 cm in diameter with the discharge-chamber surfaces in the form of segments of a sphere. The calculated thrust data are compared with the values calculated for the basic ion-source configuration with a hemispherical discharge chamber and a flat ion-extraction system. A significant increase in the extracted ion current and thrust in the established optimum ion-source configuration is obtained. | Optimizing the Design Geometry of Radio-Frequency Ion Thrusters and Ion Sources | 10.1134/S1027451023010020 |
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