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2020-07-01 | Abstract The plastic flow behavior of tensile specimens of ultrafine-grained 08G2B steel prone to strain aging was studied using digital image correlation, electron backscatter diffraction, and microindentation. Standard flat tensile specimens were tested with a constant strain rate in the initial state (after controlled rolling) and after controlled rolling + heating to 680°C for 30 min followed by air cooling. The specimen strained to δ ≈ 3% was observed to have Chernov–Luders bands. Texture analysis and microindentation were carried out in different regions outside, at the front, and within the Chernov–Luders band. It was shown that plastic flow in the Chernov–Luders band leads to an increase in microhardness and the appearance of new {112}〈111〉 and {001}〈110〉 texture components. | Plastic Flow in a Chernov–Luders Band in Ultrafine-Grained
08G2B Steel | 10.1134/S1029959920040086 |
2020-07-01 | The aim of this study was to assess the effects of IL-6 and IL-8 cytokines on human gingival fibroblasts (HGF) cultured in a 3-D model and the possible photobiomodulation (PBM) of such effects by low-level laser therapy. In complete culture medium (DMEM), HGF from a healthy patient were seeded in a type I collagen matrix inserted into 24-well plates. After 5 days of incubation, the cytokines were added or not to serum-free DMEM, which was applied to the cell-enriched matrices. Then, PBM was performed: three consecutive irradiations using LaserTable diode device (780 nm, 0.025 W) at 0.5 J/cm 2 were delivered or not to the cells. Twenty-four hours after the last irradiation, cell viability and morphology, gene expression, and synthesis of inflammatory cytokines and growth factors were assessed. The histological evaluation demonstrated that, for all groups, matrices presented homogeneous distribution of cells with elongated morphology. However, numerous cytokine-exposed cells were rounded. IL-6 and IL-8 decreased cell viability, synthesis of VEGF, and gene expression of collagen type I. PBM enhanced cell density in the matrices and stimulated VEGF expression, even after IL-6 challenge. Reduced TNF-α synthesis occurred in those cells subjected to PBM. In conclusion, PBM can penetrate collagen matrix and stimulate HGF, highlighting the relevance of this research model for further phototherapy studies and in vitro biomodulation of the healing process. | Photobiomodulation of inflammatory-cytokine-related effects in a 3-D culture model with gingival fibroblasts | 10.1007/s10103-020-02974-8 |
2020-07-01 | This study aimed to investigate the anti-inflammatory effects of different dosage of low-level laser therapy (LLLT) in an experimental model of temporomandibular joint (TMJ) arthritis. One hundred male Wistar rats were used and divided into the following groups: CG, control group; AG, animals group with left TMJ arthritis induced by intra-articular injection of Complete Freund’s adjuvant - CFA; LG5, LG10 and LG20 - animals with arthritis and treated with LLLT at doses 5, 10, and 20 J/cm 2 , respectively. Morphological analysis was performed by TMJ histological sections stained with hematoxylin-eosin (HE), picrosirius (PSR), and toluidine blue (TB), as well as histomorphometric evaluation of cartilage, articular disc, and masticatory muscles. The amount of feed consumed within 3 weeks was evaluated, and biochemical analysis of TMJ tissues included measurement of sulfated glycosaminoglycans (GAGs), matrix metalloproteinases (MMPs) 2 and 9 zymography, and ELISA for cytokines IL-6, TNF-α, and IL-1β. Only the 20 J/cm 2 dose promoted higher feed intake compared to AG. On the other hand, all LLLT doses promoted better organization of articular disc collagen fibers, greater number of proteoglycans in articular cartilage, increased area and diameter of left lateral pterygoid fibers, reduced latent and active MMP 9 and 2 activity, and lower IL-1β concentration compared to AG. Considering the study limitations, it was observed that LLLT treatments were effective in protecting and tissue cleansing joint structures, accelerating tissue repair, especially at lower doses. | Photobiostimulation activity of different low-level laser dosage on masticatory muscles and temporomandibular joint in an induced arthritis rat model | 10.1007/s10103-019-02933-y |
2020-07-01 | To find out the effect of reducing energy intake during dry period on milk production, udder health, and body condition, the experiment was conducted on 14 Jersey crossbred cows during whole dry period and continued up to 120 days of lactation. Reduction in energy intake was done during far-off period for each dry cow of treatment group as compared to control group. Statistically analyzed data revealed that overall significantly ( P < 0.01) lower DMI and WI were recorded in control than treatment group. Overall significantly ( P < 0.01) higher total milk production was found in treatment than control group. Overall significantly ( P < 0.01) lower milk SCC, MCMT, pH, and EC were found in treatment than control group. Nonsignificant difference in milk fat, SNF, total solid, total protein, and fat:protein ratio was found. Overall significantly ( P < 0.01) better quality milk (MBRT) was found in treatment than control groups. BCS during dry period and at calving was significantly ( P < 0.01) different between groups. Significantly ( P < 0.01) higher plasma NEFA concentration was estimated in control than treatment groups in all stages. No significant difference was found for plasma concentrations of glucose, urea, and total protein. The coefficients of correlation indicated significant ( P < 0.01) correlation among BCS, milk production, milk SCC, MCMT, pH, and EC. It can be concluded that reducing energy intake during far-off dry period can lead to achieve optimum BCS at calving. Suitable BCS at calving was beneficial to get higher milk production with improved quality, better maintenance of udder health and body condition of Jersey crossbred cows at tropical lower Gangetic region. | Effect of reducing energy intake during the dry period on milk production, udder health, and body condition score of Jersey crossbred cows in the tropical lower Gangetic region | 10.1007/s11250-019-02191-8 |
2020-07-01 | This article presents the low-power ternary arithmetic logic unit (ALU) design in carbon nanotube field-effect transistor (CNFET) technology. CNFET unique characteristic of geometry-dependent threshold voltage is employed in the multi-valued logic design. The ternary logic benefit of reduced circuit overhead is exploited by embedding multiple modules within a block. The existence of symmetric literals among various single shift and dual shift operators in addition and subtraction operations results in the optimized realization of adder/subtractor modules. The proposed design is based on the notion of multiplexing either arithmetic, logical or miscellaneous operations, depending upon the status of input selection trits. The results obtained by the synopsis HSPICE simulator with the Stanford 32 nm CNFET technology illustrate that the proposed processing modules outperform their counterparts in terms of power consumption, energy consumption and device count. The proposed methodology leads to saving in power consumption and energy consumption (PDP) of 62% and 58%, respectively, on the benchmark circuit of the ALU [full adder/subtractor (FAS)]. Furthermore, for the 2-trit multiplier design, the enhanced performance at the architecture and circuit level is achieved through the optimized designs of various adder and multiplier circuits. | Energy-Efficient Ternary Arithmetic Logic Unit Design in CNTFET Technology | 10.1007/s00034-019-01318-4 |
2020-07-01 | The reconstructive techniques have been widely used in Veterinary Medicine. The post-operative adjuvants therapies like the low-level laser therapy (LLLT) are used to decrease inherent complications to reconstructive surgeries. This article purposed to define the LLLT effects on the healing, inflammation, and vascularization of the skin grafts in applicable time intervals to veterinary surgical routine. Forty rats ( Rattus norvegicus albinus wistar ) were used and each one was submitted to autogenous cutaneous mesh grafting in the interescapular region. The rats were randomly distributed in five groups (G1, G2, G3, G4, and G5) in accordance with the 6 J/cm 2 or 10 J/cm 2 dose every 3 or 5 days. These treatments were applied on the skin graft for 15 days. The histochemical evaluation with Picrosirius showed greater expression of collagen type 1 – red in grafts of G5 ( p < 0.05), while in G1 did not; the expression of collagen type III – green was not induced by LLLT. The histochemical evaluation with hematoxylin-eosin showed greater numbers of fibroblasts in grafts of G4 ( p < 0.05) and less hemorrhage in grafts of G5 ( p < 0.05). There was modulation of the inflammatory response in irradiated skin grafts. It is concluded the exhibition of the skin grafts to 6 J/cm 2 or 10 J/cm 2 dose every 5 days improved the healing and the modulation of the local inflammation. | Evaluation of angiogenesis, inflammation, and healing on irradiated skin graft with low-level laser therapy in rats (Rattus norvegicus albinus wistar) | 10.1007/s10103-019-02917-y |
2020-07-01 | Cyclophosphamide (CP) is a nitrogen mustard alkylating agent with effective antineoplastic, immunomodulatory and immunosuppressive properties. Despite its vast therapeutic uses, it is known to trigger strict cardiac toxicity. The objective of the current study was to examine the protective role of metformin (MET) and/or low dose radiation (LDR) on cardiotoxicity and apoptosis induced by CP in rats. CP (200 mg/kg i.p) induces cardiotoxicity and apoptosis as indicated by elevation of troponin, cardiac caspase-3 and Endothelin-I (ET-1). While, treatment with MET (150 mg/kg, orally for 14 days) and/or LDR (0.5 Gy) before CP hindered CP-induced toxicity. By estimating the apoptotic index (BAX/Bcl-2 ratio) CP showed significantly the highest BAX/Bcl-2 ratio. Administration of MET and/or LDR showed a significant improvement in oxidative stress indices and reverse the inhibitory effect of CP on SIRT-1. Also, Histological examination of cardiac tissues showed a sign of necrosis of myocardium after CP treatment. Conclusions: The results revealed that MET and/or LDR attenuate CP-induced cardiotoxicity by inhibiting oxidative stress and preserving the activity of antioxidant enzymes through SIRT-1/SOD and BAX/Bcl-2 pathways. Graphic abstract | Metformin and/or low dose radiation reduces cardiotoxicity and apoptosis induced by cyclophosphamide through SIRT-1/SOD and BAX/Bcl-2 pathways in rats | 10.1007/s11033-020-05582-5 |
2020-07-01 | Abstract Currently, a search for selective antagonists of luteinizing hormone (LH) receptor, which are required to suppress the steroidogenesis in hormone-dependent tumors and to prevent the ovarian hyperstimulation syndrome, is carried out. One approach to tackle this problem is the development of low-molecular-weight antagonists of the allosteric site of this receptor, which is located in its transmembrane domain. The aim of this work was to develop the heterocyclic compounds, the derivatives of thieno[2,3- d ]pyrimidine (TP31), pyrimido[4,5,6- de ][1,6]naphthyridine (PP10), and pyrido[3,4- d ]pyrimidine (PP17), and to study their ability to affect the functional activity of the LH receptor in the in vitro and in vivo conditions. It was shown that TP31 at micromolar concentrations suppressed stimulating effects of human chorionic gonadotropin (hCG) and TP03, an allosteric agonist of the LH receptor, on the adenylyl cyclase activity in rat testicular membranes; its effect was most pronounced in relation to the stimulating effects of TP03. This was due to a higher selectivity of the TP31 antagonist with respect to the cAMP-dependent signaling cascades, predominantly activated by TP03 and realized through G s proteins. PP17 inhibited stimulatory effects of hCG and TP03 on the adenylyl cyclase activity to a similar extent but was less active compared to TP31. Upon intratesticular (10 mg/kg) or intraperitoneal (45 mg/kg) administration to male rats, TP31 and PP17 decreased the baseline plasma level of testosterone and inhibited the testosterone production stimulated by hCG (100 IU/rat); the inhibitory effect of TP31 was much more pronounced than that of PP17. PP10 exhibited a weaker antagonistic activity than TP31 and PP17 in the in vitro and in vivo conditions. The data obtained indicated that TP31, the most active functional antagonist among the studied compounds, binded to the allosteric site of the LH receptor, made it less accessible to allosteric agonists and impairs the hormonal signal transduction through the LH receptor. This suggests the prospects of the development of TP31-based inhibitors of LH-dependent pathways and steroidogenesis. | Low-Molecular-Weight Ligands of Luteinizing Hormone Receptor with the Activity of Antagonists | 10.1134/S1990747820030034 |
2020-07-01 | We report a case of acquired dysfibrinogenemia with monoclonal gammopathy of undetermined significance presenting λ -type IgA M protein. The patient showed lower functional (0.4 g/dL) and normal immunological fibrinogen (2.9 g/dL). To examine the cause of the false lower value of fibrinogen, we performed experiments using the patient’s purified fibrinogen and IgA. Fibrinogen was purified from the patient’s plasma; IgA was purified from plasma or serum by immunoaffinity chromatography. We performed thrombin-catalyzed fibrin polymerization, scanning electron microscopy (SEM), immunoblotting analysis, and enzyme-linked immunosorbent assays (ELISAs). Fibrin polymerization in the patient’s plasma was markedly reduced and SEM showed no fiber bundles or sponge-like structures. Purified IgA did not influence polymerization, whereas immunoprecipitated plasma with an anti-IgA ( α -chain) antibody indicated normalization of polymerization and clot structure. Western blotting analysis revealed the presence of monoclonal λ -type IgA-bound fibrinogen, the proportion of which was significantly higher than normal control plasma using ELISA. Our results suggest that IgA M protein-bound fibrinogen is not normally converted into fibrin, but rather leads to formation of an aberrantly structured fragile clot. The patient’s reduced plasma fibrinogen level was caused by the presence of IgA M protein-bound fibrinogen, not by IgA M protein alone. | Acquired dysfibrinogenemia: monoclonal λ-type IgA binding to fibrinogen caused lower functional plasma fibrinogen level and abnormal clot formation | 10.1007/s12185-020-02874-1 |
2020-07-01 | Objective To observe the effect of electroacupuncture (EA) at Lower He-Sea points on the expression levels of interleukin-1β (IL-1β) in the serum and gallbladder tissues, and nuclear factor-κB (NF-κB) in gallbladder tissues of the guinea pigs with acute cholecystitis (AC), and to explore whether Yanglingquan (GB 34), the Lower He-Sea point pertaining to Dan Fu (gallbladder), is relatively specific for the Dan Fu (gallbladder) disorders. Methods Eighty-two healthy guinea pigs were randomly divided into 6 groups according to the random number table method, a blank group, a model group, a Yanglingquan (GB 34) group, a Zusanli (ST 36) group, a Shangjuxu (ST 37) group, and a Xiajuxu (ST 39) group, with 12 guinea pigs in the blank group while 14 in the other groups, respectively, half males and half females in each group. Except for the blank group, guinea pigs in the other groups were injected with E. coli into the gallbladder to establish AC models. Guinea pigs in the blank group were fed routinely without special treatment; those in the model group were daily tied up for 30 min without EA treatment; those in the 4 groups receiving EA treatment were acupunctured at the corresponding Lower He-Sea points after daily binding and stimulated with the SDZ-V EA instrument. After successful modeling and treatment for 5 d, blood was collected from the abdominal aorta of the guinea pigs, and the gallbladder tissues in each group were isolated for hematoxylin-eosin (HE) staining to observe the morphological changes. Enzyme-linked immunosorbent assay (ELISA) was used to detect the serum IL-1β level, and immunohistochemistry (IHC) was used to detect the expression levels of NF-κB and IL-1β in gallbladder. Results On the 3rd day after modeling, the guinea pigs in the five groups with modeling were mentally depressed with decreased appetite, significantly reduced activities, slouch, lassitude, slack and matted fur, and loose stools; two guinea pigs were selected from each group (one male and one female, not included in the final statistics) to isolate the gallbladder after sacrifice; macroscopic observation showed that the gallbladder wall was differently thickened; the bile color was dark green and opaque with particles suspended or accumulated; light microscope observation showed that the submucosal blood vessels of the gallbladder were congested, along with mucosal edema, ulceration, necrosis, shedding, and a large number of inflammatory cells infiltrating in the lamina propria, indicating that the AC model was successfully prepared. Compared with the model group, the gallbladder tissue injuries of the four groups receiving EA treatment were all differently repaired, the serum IL-1β levels were reduced ( P <0.01 or P <0.05), and the IL-1β levels in the gallbladder tissues were reduced ( P <0.01 or P <0.05). Compared with the model group, the NF-κB expression level in the Yanglingquan (GB 34) group was significantly reduced ( P <0.01), but was not statistical different in the Zusanli (ST 36) group, Shangjuxu (ST 37) group and Xiajuxu (ST 39) group (all P >0.05). Compared with the Yanglingquan (GB 34) group, the gallbladder tissues of the Zusanli (ST 36) group, Shangjuxu (ST 37) group and Xiajuxu (ST 39) group were more severely damaged, and the expression levels of serum IL-1β, the NF-κB and IL-1β in the gallbladder tissues were increased ( P <0.01 or P <0.05). Intervention effect of Yanglingquan (GB 34) on AC guinea pigs was superior to that of Zusanli (ST 36), Shangjuxu (ST 37) and Xiajuxu (ST 39). Conclusion EA at the Lower He-Sea points of the stomach, large intestine, small intestine and gallbladder can produce curative effects on AC guinea pigs and reduced the inflammatory symptoms. Intervention effect of Yanglingquan (GB 34) on AC guinea pigs is superior to that of Zusanli (ST 36), Shangjuxu (ST 37) and Xiajuxu (ST 39). The mechanism of EA at Yanglingquan (GB 34) in treating AC may be regulating IL-1β and NF-κB to control the inflammatory response and improve the gallbladder tissue damage. 目的 观察电针急性胆囊炎(AC)模型豚鼠下合穴对血清及胆囊组织白介素-1β(IL-1β)和胆囊组织核因子-κB (NF-κB)表达的影响, 探讨胆的下合穴阳陵泉对胆腑病变是否存在相对特异性. 方法 将82只健康豚鼠按照随机数 字表法随机分为空白组12只, 模型组、阳陵泉组、足三里组、上巨虚组和下巨虚组, 每组14只, 均雌雄各半. 除 空白组外, 其余组豚鼠均予胆囊内注射大肠杆菌建立AC模型. 空白组正常饲养而无特殊处理; 模型组每日捆绑 30 min但不做电针治疗; 接受电针治疗的4组每天捆绑后针刺相应下合穴, 并使用SDZ-V型电子针疗仪进行刺激. 造模成功并治疗5 d后, 行豚鼠腹主动脉采血, 取胆囊组织进行苏木素-伊红(HE)染色, 观察各组豚鼠胆囊形态学 变化, 酶联免疫吸附(ELISA)法检测血清中IL-1β含量, 免疫组织化学(IHC)法检测胆囊NF-κB及IL-1β的表达. 结果 造 模后第3天, 接受造模的5组豚鼠精神萎靡, 食欲下降, 活动明显减少; 弓背倦怠, 皮毛松, 无光泽, 大便稀; 每组 各取2只(雌雄各1只, 不纳入统计), 处死后取整个胆囊, 肉眼观察胆囊, 胆囊壁不同程度增厚, 胆汁颜色呈深绿色, 不透明, 有颗粒悬浮或堆积; 光镜下观察, 胆囊黏膜下血管充血, 有黏膜水肿、溃疡、坏死、脱落, 固有层有大量 炎细胞浸润, 提示豚鼠AC造模成功. 与模型组比, 接受电针治疗的4组胆囊组织损伤均有不同程度修复, 血清中 IL-1β含量均降低( P <0.01或 P <0.05), 胆囊组织中IL-1β含量均降低( P <0.01或 P <0.05). 与模型组比较, 阳陵泉组 NF-κB表达明显降低( P <0.01), 足三里组、上巨虚组和下巨虚组NF-κB表达无统计学差异(均 P >0.05). 与阳陵泉组 比, 足三里组、上巨虚组和下巨虚组胆囊组织损伤较严重, 血清中IL-1β含量及胆囊组织中NF-κB及IL-1β表达增高 ( P <0.01或 P <0.05). 结论 电针胃、大肠、小肠及胆的下合穴均可对AC模型豚鼠产生疗效, 减轻炎性症状. 阳 陵泉对AC模型豚鼠的干预效应优于足三里、上巨虚和下巨虚. 电针阳陵泉治疗AC的机制可能是通过调节IL-1β及 NF-κB等调控炎症反应, 改善胆囊组织损伤. | Effect of electroacupuncture at Lower He-Sea points including Yanglingquan (GB 34) on nuclear factor-κB and interleukin-1β in guinea pigs with acute cholecystitis | 10.1007/s11726-020-1184-x |
2020-07-01 | Abstract The composition, structure, and secondary alteration of the Lower Devonian sedimentary rocks are characterized; the distribution of various types of pore spaces is analyzed and several types of dolomite structures are distinguished. The results of our works indicate that, depending on the permeability, solubility, and primary structure of the carbonate rocks or sediment, as well as the temperature, volume, and duration of influence of dolomitizing fluids, dolomitization can lead to an increase or decrease in porosity. | Secondary Dolomitization as a Factor Responsible for the Reservoir Properties of the Lower Devonian Sedimentary Rocks of the Eastern Wall of the Khoreiver Depression (Timan–Pechora Petroleum Basin) | 10.3103/S014587522004016X |
2020-06-30 | Effects of high-pressure (HP) treatment on densification of poplar sapwood boards and subsequent coatings were evaluated. Tung oil (TO) and epoxy resin (ER)-coated treatments were used to improve the dimensional stability of HP-densified wood. The density of the wood after HP densification increased from 450 ± 50 kg/m 3 for the control to 960 ± 20 kg/m 3 at 125 MPa. This process also resulted in the average thickness of HP-densified boards to reduce significantly from 29.7 ± 0.11 mm for the control to 18.8 ± 0.53 mm after HP densification at 25 MPa and 14.3 ± 0.10 mm after 125 MPa treatment for 30 s. The mechanical strength measured as the hardness of densified wood significantly increased from 35% at 25 MPa to 96% at 125 MPa treatment, compared to untreated wood. As expected both TO and ER-coated treatments significantly reduced set-recovery of densified wood when stored at four relative humidity environments. ER showed better anti-swelling performance than TO, and would be a better choice. | High-pressure densification and hydrophobic coating for enhancing the mechanical properties and dimensional stability of soft poplar wood boards | 10.1186/s10086-020-01892-1 |
2020-06-29 | Background The objective of this prospective, multicentre, observational cohort study was to evaluate the association between admission hypothermia and neonatal outcomes in very low-birth weight (VLBW) infants in multiple neonatal intensive care units (NICUs) in China. Methods Since January 1, 2018, a neonatal homogeneous cooperative research platform-Shandong Neonatal Network (SNN) has been established. The platform collects clinical data in a prospective manner on preterm infants with birth weights (BWs) < 1500 g and gestational ages (GAs) < 34 weeks born in 28 NICUs in Shandong Province. These infants were divided into normothermia, mild or moderate/severe hypothermia groups according to the World Health Organization (WHO) classifications of hypothermia. Associations between outcomes and hypothermia were tested in a bivariate analysis, followed by a logistic regression analysis. Results A total of 1247 VLBW infants were included in this analysis, of which 1100 infants (88.2%) were included in the hypothermia group, 554 infants (44.4%) in the mild hypothermia group and 546 infants (43.8%) in the moderate/severe hypothermia group. Small for gestational age (SGA), caesarean section, a low Apgar score at 5 min and intubation in the delivery room (DR) were related to admission hypothermia (AH). Mortality was the lowest when their admission temperature was 36.5 ~ 37.5 °C, and after adjustment for maternal and infant characteristics, mortality was significantly associated with AH. Compared with infants with normothermia (36.5 ~ 37.5 °C), the adjusted ORs of all deaths increased to 4.148 (95% CI 1.505–11.437) and 1.806 (95% CI 0.651–5.009) for infants with moderate/severe hypothermia and mild hypothermia, respectively. AH was also associated with a high likelihood of respiratory distress syndrome (RDS), intraventricular haemorrhage (IVH), and late-onset neonatal sepsis (LOS). Conclusions AH is still very high in VLBW infants in NICUs in China. SGA, caesarean section, a low Apgar score at 5 min and intubation in the DR were associated with increased odds of hypothermia. Moderate/severe hypothermia was associated with mortality and poor outcomes, such as RDS, IVH, LOS. | Association between admission hypothermia and outcomes in very low birth weight infants in China: a multicentre prospective study | 10.1186/s12887-020-02221-7 |
2020-06-29 | Background Malaria and HIV are common infections in Africa and cause substantial morbidity and mortality in pregnant women. We aimed to assess the association of malaria with anemia in pregnant women and to explore the joint effects of malaria and HIV infection on anemia in pregnant women. Methods We used nationally representative, cross-sectional demographic and health surveys (DHS) that were conducted between 2012 and 2017 across 7 countries of sub-Saharan Africa (Burundi, the Democratic Republic of the Congo, Gambia, Ghana, Mali, Senegal and Togo). The outcome variables were anemia (defined as a hemoglobin concentration < 110 g/L), and hemoglobin concentration on a continuous scale, in pregnant women at the time of the interview. We used generalized linear mixed-effects models to account for the nested structure of the data. We adjusted models for individual covariates, with random effects of the primary sampling unit nested within a country. Results A total of 947 pregnant women, ages, 15–49 y, were analyzed . Prevalence of malaria only, HIV only, and malaria- HIV coinfection in pregnant women was 31% (95% CI: 28.5 to 34.5%, n = 293), 1.3% (95% CI: 0.77 to 2.4%, n = 13) and 0.52% (95% CI: 0.02 to 1.3%, n = 5) respectively. Overall prevalence of anemia was 48.3% (95% CI: 45.1 to 51.5%). The anemia prevalence in pregnant women with malaria infection only was 56.0% (95% CI: 50.1 to 61.7%); HIV infection only, 62.5% (95% CI: 25.9 to 89.8%); malaria- HIV coinfection, 60.0 (95% CI: 17.0–92.7%) and without either infection, 44.6% (95% CI: 40.7 to 48.6%). In the fully adjusted models, malaria infection was associated with 27% higher prevalence of anemia (95% CI of prevalence ratio: 1.12 to 1.45; p = 0.004), and 3.4 g/L lower hemoglobin concentration (95% CI: - 5.01 to − 1.79; p = 0.03) compared to uninfected pregnant women. The prevalence of HIV infection and malaria-HIV coinfection was too low to allow meaningful analysis of their association with anemia or hemoglobin concentration. Conclusion Malaria was associated with an increased prevalence of anemia during pregnancy. | Associations of malaria, HIV, and coinfection, with anemia in pregnancy in sub-Saharan Africa: a population-based cross-sectional study | 10.1186/s12884-020-03064-x |
2020-06-28 | Rainfall and surface runoff are the two most important components, which control the groundwater recharge of the basin. The long-term groundwater recharge of an aquifer gets affected by the population growth, irregular agriculture activities and industrialization. Hence, estimation of rainfall-surface runoff is very much essential for proper groundwater management practices. In the present study, Soil Conservation Service Curve Number (SCS-CN) model was employed in combination with geospatial techniques to estimate rainfall-surface runoff for the Lower Bhavani River basin in South India. To develop the SCS-CN model, rainfall data were obtained for 33 years (1983–2015) from 22 rain gauge stations spread over the basin. IRS LISS-IV satellite data of 5.8 m spatial resolution were used to analyze the land use/land cover (LU/LC) behavior. Based on the soil properties, four Hydrological Soil Groups (HSG) were identified in the basin which is most significant for surface runoff estimation. Curve Number (CN) values were obtained for various Antecedent Moisture Conditions (AMC) such as dry condition (AMC I), average condition (AMC II) and wet condition (AMC III). Spatial distribution of CN values was plotted using Geographical Information System (GIS) for the entire Lower Bhavani Basin to assess the surface runoff potential. The results indicate that the annual rainfall varies from 267 mm (2002) to 1528.6 mm (2005), and the annual surface runoff varies from 102.04 mm (1985) to 463.02 mm (2010). The SCS-CN model outputs predict that the average surface runoff of the basin is 211.99 mm, and the average surface runoff volume is 81,995,380 m 3 . The study also indicates that nearly 53% of the basin area is dominated by high to very high surface runoff potential. Finally, the output of surface runoff potential was validated with the Average Groundwater Level Fluctuation (AGLF) observed in 57 wells spread over the entire basin. The basin AGLF ranges from 2.32 to 21.72 m. The surface runoff potential categories are satisfactorily matching with the AGLF categories. Moderate surface runoff as well as moderate AGLF zones mostly occupy the central portion of the basin, which possess good groundwater potential. However, the high surface runoff zones in the basin lead more surface water flow into the river channels, which reduce the infiltration rate and decline the water table. This problem can be solved by constructing suitable artificial groundwater recharge structures across the river channels in the high surface runoff potential areas. | Rainfall-surface runoff estimation for the Lower Bhavani basin in south India using SCS-CN model and geospatial techniques | 10.1007/s12665-020-09079-z |
2020-06-27 | Background For infants undergoing complex cardiac surgery, hemodynamic management after cardiopulmonary bypass (CPB) is challenging because of severe myocardial edema, vasomotor dysfunction and weak tolerance to a change in blood volume. More importantly, the lack of availability of equipment for advanced monitoring, such as transesophageal echocardiography or transthoracic echocardiography, restricts the accurate assessment of hemodynamics. Case presentation This is a case of severe hypotension and non-detectable pulse oxygen saturation (SpO 2 ) after CPB in a low-weight infant who had normal blood pressure and oxygen saturation before surgery. Epinephrine and milrinone were administered with cerebral oximetry monitoring rather than blood pressure measurements because cerebral oximetry was more responsive to treatment than blood pressure. Under the guidance of cerebral oximetry, the infant was successfully weaned from CPB and recovered after surgery without adverse neurological events. Conclusions For infants who develop refractory hypotension and failure in SpO 2 monitoring during the CPB weaning period, cerebral oximetry provides an index for assessing brain perfusion and valuable guidance for appropriate inotropic treatment. | Severe low cerebral oximetry in difficult cardiopulmonary bypass weaning of low body-weight infant: a case report and literature review | 10.1186/s12871-020-01071-1 |
2020-06-26 | With the purpose of enhancing the photocatalytic activity of titania (TiO 2 ) coatings with low cost, a method of sulfuric-acid-bath pretreatment followed by simple oxidation in air has been proposed to fabricate TiO 2 coatings. The effect of oxidation temperature on the crystal structure, surface morphologies and photocatalytic activity of TiO 2 coatings was investigated, to figure out the suitable oxidation temperature. XRD and Raman’s results show that the phase transformation of TiO 2 starts at 773 K. The surface morphologies of TiO 2 coatings clearly show the porous-like structure at lower than 873 K. With raising the temperature, the photocatalytic activity of TiO 2 coatings firstly increases, then decreases, and reaches the highest at relatively low oxidation temperature of 773 K. | Enhanced photocatalytic activity of titania coatings fabricated at relatively low oxidation temperature with sulfate-acid-bath pretreatment | 10.1007/s00339-020-03597-0 |
2020-06-24 | The World Health Organization and other institutions are considering Artificial Intelligence (AI) as a technology that can potentially address some health system gaps, especially the reduction of global health inequalities in low- and middle-income countries (LMICs). However, because most AI-based health applications are developed and implemented in high-income countries, their use in LMICs contexts is recent and there is a lack of robust local evaluations to guide decision-making in low-resource settings. After discussing the potential benefits as well as the risks and challenges raised by AI-based health care, we propose five building blocks to guide the development and implementation of more responsible, sustainable, and inclusive AI health care technologies in LMICs. | Artificial intelligence in health care: laying the Foundation for Responsible, sustainable, and inclusive innovation in low- and middle-income countries | 10.1186/s12992-020-00584-1 |
2020-06-23 | Experimental results of dynamic contact angle measurements of low salinity brine and combined low salinity water and surfactant flooding (LSW–SF) on silica surface are presented in this study. Dynamic contact angle experiments were carried out for four crude oil samples with low salinity brines and combined low salinity and sodium dodecylbenzene sulfonate (SDBS) solutions. Similar measurements with the same ion strength in presence of different cations, Na + and Ca 2+ , for low salinity injections and combined low salinity–SDBS solutions were also carried out to study the change in dynamic contact angles and wetting behavior. The presences of different cations change the initial contact angles in low salinity solution injections and show different dynamic behaviors in presence of different crude oils. The signs and values of the line tension to oil/water interfacial tension ratios have been calculated from the size dependence of the dynamic contact angle measurements on the silica coated quartz crystal microbalance sensors. Analysis indicates positive line tension values for low salinity brine systems and negative values for LSW–SF systems. Injection of surfactant solutions in presence of electrolyte prompts the spreading of the oil droplet over the surface, which is induced by interfacial tension gradient from the top of the oil droplet toward the contact line. The results indicated that spreading time, which is the required time for oil drop to gradually flatten out, is dependent on type of electrolytes and is a function of surface excess concentration of the surfactant. | Dynamic wettability alteration for combined low salinity brine injection and surfactant flooding on silica surface | 10.1007/s42452-020-3094-4 |
2020-06-22 | Recently, reported perovskite solar cells (PSCs) with high power conversion efficiency (PCE) are mostly based on mesoporous structures containing mesoporous titanium oxide (TiO 2 ) which is the main factor to reduce the overall hysteresis. However, existing fabrication approaches for mesoporous TiO 2 generally require a high-temperature annealing process. Moreover, there is still a long way to go for improvement in terms of increasing the electron conductivity and reducing the carrier recombination. Herein, a facile one-step, in situ, and low-temperature method was developed to prepare an Nb:TiO 2 compact-mesoporous layer which served as both scaffold and electron transport layer (ETL) for PSCs. The Nb:TiO 2 compact-mesoporous ETL-based PSCs exhibit suppressed hysteresis, which is attributed to the synergistic effect of the increased interface surface area caused by nano-pin morphology and the improved carrier transportation caused by Nb doping. Such a high-quality compact-mesoporous layer allows the PSCs assembled using optimized 2% Nb-doped TiO 2 to achieve a remarkable PCE of 19.74%. This work promises an effective approach for creating hysteresis-less and high-efficiency PSCs based on compact-mesoporous structures with lower energy consumption and cost. | In Situ-Formed and Low-Temperature-Deposited Nb:TiO2 Compact-Mesoporous Layer for Hysteresis-Less Perovskite Solar Cells with High Performance | 10.1186/s11671-020-03366-1 |
2020-06-15 | Since the novel coronavirus disease 2019 (COVID-19) has been identified in Wuhan, China, in the last week of December, the virus has spread across nations and continents affecting over 3 million people and putting the whole world to a halt. Nations across the globe went on lockdown in an attempt to contain the spread of the virus and curb its propagation curve. Affected African countries did the same except for Benin, which opted for a sanitary cordon around the affected regions with free movement of people. The biggest challenge is the effectiveness of this measure. | Benin responds to covid-19: sanitary cordon without generalized containment or lockdown? | 10.1186/s41182-020-00235-6 |
2020-06-15 | Introduction Quality improvement in the administration of extracorporeal cardiopulmonary resuscitation (ECPR) over time and its association with low-flow duration (LFD) and outcomes of cardiac arrest (CA) have been insufficiently investigated. In this study, we hypothesized that quality improvement in efforts to shorten the duration of initiating ECPR had decreased LFD over the last 15 years of experience at an academic tertiary care hospital, which in turn improved the outcomes of in-hospital CA (IHCA). Methods This was a single-center retrospective observational study of ECPR patients between January 2003 and December 2017. A rapid response system (RRS) and an extracorporeal membrane oxygenation (ECMO) program were initiated in 2011 and 2013. First, the association of LFD per minute with the 90-day mortality and neurological outcome was analyzed using multiple logistic regression analysis. Then, the temporal changes in LFD were investigated. Results Of 175 study subjects who received ECPR, 117 had IHCA. In the multivariate logistic regression, IHCA patients with shorter LFD experienced significantly increased 90-day survival and favorable neurological outcomes (LFD per minute, 90-day survival: odds ratio [OR] = 0.97, 95% confidence interval [CI] = 0.94–1.00, P = 0.032; 90-day favorable neurological outcome: OR = 0.97, 95% CI = 0.94–1.00, P = 0.049). In the study period, LFD significantly decreased over time (slope − 5.39 [min/3 years], P < 0.0001). Conclusion A shorter LFD was associated with increased 90-day survival and favorable neurological outcomes of IHCA patients who received ECPR. The quality improvement in administering ECPR over time, including the RRS program and the ECMO program, appeared to ameliorate clinical outcomes. | Shortening of low-flow duration over time was associated with improved outcomes of extracorporeal cardiopulmonary resuscitation in in-hospital cardiac arrest | 10.1186/s40560-020-00457-0 |
2020-06-15 | Background Mounting evidence suggested a complex correlation between host lipid metabolism and Toxoplasma gondii ( T. gondii ) infection. However, the inherent association between T. gondii infection and host lipid state remains elusive either in mice or in human hosts. Methods Through a study in a sample of 1045 healthy participants from eastern China, we determined the association of T. gondii infection and host lipid levels using serological methods. We then examined the host lipid levels in C57BL/6 J mice at both acute and chronic T. gondii infection stages (for a period up to 36 weeks post infection). Results In our case-control study, T. gondii seropositive individuals had higher low-density lipoproteins (LDL) ( P = 0.0043) and total cholesterol (TC) ( P = 0.0134) levels compared to seronegative individuals. Furthermore, individuals with LDL (OR = 3.25; 95% CI:1.60–6.61) and TC (OR = 2.10; 95% CI:1.22–3.63) levels above the upper limit of normal range had higher odds ratio to be T. gondii IgG positive. Consistently, in vivo data revealed that a significantly increased LDL level was first observed at early acute stage but plateaued to later time (chronic infection with T. gondii ). Conclusions In both healthy population and T. gondii -infected mice, seropositive individuals had higher LDL level. Individuals with positive T. gondii IgG had more odds of being with LDL and TC abnormality. Latent T. gondii infection is common worldwide, potential medical interventions to host lipid metabolism may be a breakthrough point to the prevention and control of this parasite infection. | The influence of exposure to Toxoplasma Gondii on host lipid metabolism | 10.1186/s12879-020-05138-9 |
2020-06-12 | Stormwater represents a major non-point pollution source at an urban environment. To improve the treatment efficacy of stormwater infrastructure, low-cost adsorbents have increasingly gained attention over the past decades. This article aims to briefly discuss several key aspects and principles for utilization of low-cost adsorbents for urban stormwater treatment. To determine whether a low-cost adsorbent is suitable for stormwater treatment, two aspects should be carefully assessed, including: 1) its adsorption mechanisms and behaviors that can influence the binding strength, adsorption kinetics, and treatment capacity; and 2) unwanted chemical leaching patterns that can affect the extent of water quality degradation. Furthermore, the application mode of an adsorbent in the system design influences the utilization efficiency. Adsorbents, after dosed to soil media in infrastructure, would eventually become ineffective after oversaturation. In contrast, standalone filters or innovative composite adsorbents (e.g., adsorbent-coated mulch chips) can enable a long-lasting adsorption due to periodic replacement with fresh adsorbents. The aforementioned principles play a key role in the success of urban stormwater treatment with low-cost adsorbents. | Low-cost adsorbents for urban stormwater pollution control | 10.1007/s11783-020-1262-9 |
2020-06-12 | Background People with chronic low back pain (LBP) typically have increased pain sensitivity compared to healthy controls, however its unknown if pain sensitivity differs based on LBP trajectory at baseline or after manual therapy interventions. We aimed to compare baseline pressure pain threshold (PPT) and temporal summation (TS) between people without LBP, with episodic LBP, and with persistent LBP, and to compare changes over time in PPT and TS after a lumbar spinal manipulation or sham manipulation in those with LBP. Methods Participants were aged 18–59, with or without LBP. Those with LBP were categorised as having either episodic or persistent LBP. PPT and TS were tested at baseline. LBP participants then received a lumbar spinal manipulation or sham, after which PPT and TS were re-tested three times over 30 min. Generalised linear mixed models were used to analyse data. Results One hundred participants (49 female) were included and analysed. There were 20 non-LBP participants (mean age 31 yrs), 23 episodic LBP (mean age 35 yrs), and 57 persistent LBP (mean age 37 yrs). There were no significant differences in PPT or TS between groups at baseline. There was a non-significant pattern of lower PPT (higher sensitivity) from the non-LBP group to the persistent LBP group at baseline, and high variability. Changes in PPT and TS after the interventions did not differ between the two LBP groups. Discussion We found no differences between people with no LBP, episodic LBP, or persistent LBP in baseline PPT or TS. Changes in PPT and TS following a lumbar manual therapy intervention do not appear to differ between LBP trajectories. Trial registration The trial was prospectively registered with ANZCTR ( ACTRN12617001094369 ). | Pressure pain threshold and temporal summation in adults with episodic and persistent low back pain trajectories: a secondary analysis at baseline and after lumbar manipulation or sham | 10.1186/s12998-020-00326-5 |
2020-06-09 | Background Healthcare-associated infections (HAI) especially outbreaks of multi-drug-resistant organisms within hospitals are recognized as a major contributor to morbidity and mortality of hospitalized patients. The healthcare environment can act as an amplifier of HAI during outbreaks. The risk of acquiring HAI are 20 times higher in Low-and-middle-income countries. The purpose of this article is to review the challenges associated with controlling environmental contamination in low and lower-middle income countries (LMIC), highlighting possible solutions. Method This is a narrative review. A literature search was carried out in Google scholar, PubMed, Science Direct, EBSCOHOST, CENGAGE, Scopus, ProQuest, Clinical Key and African journals online using the key words - Health care Associated Infections (HCAIs) in LMICs, Challenges of HAIs in LMIC, Challenges of Prevention and Control of HAIs in LMICs, Environment of care and infection transmission, Contaminated environment and HAIs. Results From the accessed databases, 1872 articles related to environmental sources of contamination in healthcare settings were found. Of these, only 530 articles focused on LMICs. However, only 186 articles met the inclusion criteria studies published in English, conducted between 2000 and 2019 and exploring environmental sources of contamination in LMIC healthcare settings). The sources of environmental contamination in healthcare are numerous and commonly associated with poor governance, Inadequate infrastructure, human capacity and inadequate funding. Low awareness exists at all levels as to the role of the environment in healthcare outcomes and may explain in part the low priority given for funding. Conclusion Leadership and trained personnel, both Infection prevention and control practitioners and cleaners are crucial to drive and sustain the process to reduce environmental contamination in healthcare environments. | Challenges regarding the control of environmental sources of contamination in healthcare settings in low-and middle-income countries - a narrative review | 10.1186/s13756-020-00747-0 |
2020-06-09 | Background An epidemiological transition is interesting Sub-Saharan Africa increasing the burden of non-communicable diseases most of which are of surgical interest. Local resources are far from meeting needs and, considering that 50% of the population is less than 14 years of age, Pediatric surgical coverage is specially affected. Efforts are made to improve standards of care and to increase the number of Pediatric surgeons through short-term specialist surgical Missions, facilities supported by humanitarian organization, academic Partnership, training abroad of local surgeons. This study is a half term report about three-years Partnership between the University of Chieti- Pescara, Italy and the University of Gezira, Sudan to upgrade standard of care at the Gezira National Centre for Pediatric Surgery (GNCPS) of Wad Medani. Four surgical Teams per year visited GNCPS. The Program was financed by the Italian Agency for Development Cooperation. Methods The state of local infrastructure, current standard of care, analysis of caseload, surgical activity and results are reported. Methods utilized to assess local needs and to develop Partnership activities are described. Results Main surgical task of the visiting Team were advancements in Colorectal procedures, Epispadias/Exstrophy Complex management and Hypospadias surgery (20% of major surgical procedures at the GNCPS). Intensive care facilities and staff to assist more complex cases (i.e. neonates) are still defective. Proctoring, training on the job of junior surgeons, anaesthetists and nurses, collaboration in educational programs, advisorship in hospital management, clinical governance, maintenance of infrastructure together with training opportunities in Italy were included by the Program. Despite on-going efforts, actions have not yet been followed by the expected results. More investments are needed on Healthcare infrastructures to increase health workers motivation and prevent brain drain. Conclusions The key role that an Academic Partnership can play, acting through expatriated Teams working in the same constrained contest with the local workforce, must be emphasized. Besides clinical objectives, these types of Global Health Initiatives address improvement in management and clinical governance. The main obstacles to upgrade standard of care and level of surgery met by the Visiting Team are scarce investments on health infrastructure and a weak staff retention policy, reflecting in poor motivation and low performance. | Improving standard of pediatric surgical care in a low resource setting: the key role of academic partnership | 10.1186/s13052-020-00827-2 |
2020-06-08 | The longitudinal sound velocity ( V P ) and the density ( ρ ) of wüstite, FeO, were measured at pressures of up to 112.3 GPa and temperatures of up to 1700 K using both inelastic X-ray scattering and X-ray diffraction combined with a laser-heated diamond-anvil cell. The linear relationship between V P and ρ , Birch’s law, for wüstite can be expressed as V P = 1.55 (1) × ρ [g/cm 3 ] − 2.03 (8) [km/s] at 300 K and V P = 1.61 (1) × ρ [kg/m 3 ] − 2.82 (10) [km/s] at 1700 K. The sound velocity of wüstite is significantly lower than that of bridgmanite and ferropericlase under lower mantle conditions. In other words, the existence of wüstite in the lower mantle can efficiently decrease the seismic velocity. Considering its slow velocity and several mechanisms for the formation of FeO-rich regions at the core–mantle boundary, we confirm earlier suggestions indicating that wüstite enrichment at the bottom of the Earth’s mantle may contribute to the formation of denser ultra-low velocity zones. | The sound velocity of wüstite at high pressures: implications for low-velocity anomalies at the base of the lower mantle | 10.1186/s40645-020-00333-3 |
2020-06-05 | Background There is a steadily increasing quantity of silver nanoparticles (AgNP) produced for numerous industrial, medicinal and private purposes, leading to an increased risk of inhalation exposure for both professionals and consumers. Particle inhalation can result in inflammatory and allergic responses, and there are concerns about other negative health effects from either acute or chronic low-dose exposure. Results To study the fate of inhaled AgNP, healthy adult rats were exposed to 1½-hour intra-tracheal inhalations of pristine 105 Ag-radiolabeled, 20 nm AgNP aerosols (with mean doses across all rats of each exposure group of deposited NP-mass and NP-number being 13.5 ± 3.6 μg, 7.9 ± 3.2•10 11 , respectively). At five time-points (0.75 h, 4 h, 24 h, 7d, 28d) post-exposure (p.e.), a complete balance of the [ 105 Ag]AgNP fate and its degradation products were quantified in organs, tissues, carcass, lavage and body fluids, including excretions. Rapid dissolution of [ 105 Ag]Ag-ions from the [ 105 Ag]AgNP surface was apparent together with both fast particulate airway clearance and long-term particulate clearance from the alveolar region to the larynx. The results are compatible with evidence from the literature that the released [ 105 Ag]Ag-ions precipitate rapidly to low-solubility [ 105 Ag]Ag-salts in the ion-rich epithelial lining lung fluid (ELF) and blood. Based on the existing literature, the degradation products rapidly translocate across the air-blood-barrier (ABB) into the blood and are eliminated via the liver and gall-bladder into the small intestine for fecal excretion. The pathway of [ 105 Ag]Ag-salt precipitates was compatible with auxiliary biokinetics studies at 24 h and 7 days after either intravenous injection or intratracheal or oral instillation of [ 110m Ag]AgNO 3 solutions in sentinel groups of rats. However, dissolution of [ 105 Ag]Ag-ions appeared not to be complete after a few hours or days but continued over two weeks p.e. This was due to the additional formation of salt layers on the [ 105 Ag]AgNP surface that mediate and prolonge the dissolution process. The concurrent clearance of persistent cores of [ 105 Ag]AgNP and [ 105 Ag]Ag-salt precipitates results in the elimination of a fraction > 0.8 (per ILD) after one week, each particulate Ag-species accounting for about half of this. After 28 days p.e. the cleared fraction rises marginally to 0.94 while 2/3 of the remaining [ 105 Ag]AgNP are retained in the lungs and 1/3 in secondary organs and tissues with an unknown partition of the Ag species involved. However, making use of our previous biokinetics studies of poorly soluble [ 195 Au]AuNP of the same size and under identical experimental and exposure conditions (Kreyling et al., ACS Nano 2018), the kinetics of the ABB-translocation of [ 105 Ag]Ag-salt precipitates was estimated to reach a fractional maximum of 0.12 at day 3 p.e. and became undetectable 16 days p.e. Hence, persistent cores of [ 105 Ag]AgNP were cleared throughout the study period. Urinary [ 105 Ag]Ag excretion is minimal, finally accumulating to 0.016. Conclusion The biokinetics of inhaled [ 105 Ag]AgNP is relatively complex since the dissolving [ 105 Ag]Ag-ions (a) form salt layers on the [ 105 Ag]AgNP surface which retard dissolution and (b) the [ 105 Ag]Ag-ions released from the [ 105 Ag]AgNP surface form poorly-soluble precipitates of [ 105 Ag]Ag-salts in ELF. Therefore, hardly any [ 105 Ag]Ag-ion clearance occurs from the lungs but instead [ 105 Ag]AgNP and nano-sized precipitated [ 105 Ag]Ag-salt are cleared via the larynx into GIT and, in addition, via blood, liver, gall bladder into GIT with one common excretional pathway via feces out of the body. | Quantitative biokinetics over a 28 day period of freshly generated, pristine, 20 nm silver nanoparticle aerosols in healthy adult rats after a single 1½-hour inhalation exposure | 10.1186/s12989-020-00347-1 |
2020-06-04 | Micro-physicochemical characteristics and low-temperature SCR activities of the Mn–Ce–Cr catalysts on different carriers were investigated with SEM, XRD, XPS, FTIR, and denitration experiments. Mn–Ce–Cr catalysts carried on TiO 2 and ZrO 2 , and composite carrier containing Al 2 O 3 and TiO 2 had visible element interactions on the surfaces, and Mn presented the mixed valences of Mn 3+ and Mn 4+ . Mn 3+ was transferred to Mn 4+ due to the oxidation processes of Ce 3+ to Ce 4+ and Cr 3+ to Cr 6+ , and the O α /O β ratio decreased during the SCR process. Compared with single carriers such as TiO 2 or ZrO 2 , the catalysts on the composite carriers of Al 2 O 3 and TiO 2 had better pore structures and higher fractions of Mn 4+ , Ce 3+ , Cr 6+ , and chemisorbed oxygen. It could also absorb the coordination-state NH 3 well, especially the higher activity l -acid sites during the SCR process, and contribute to the formation of composite oxide Mn x Ti 1 −x O on Mn–Ce–Cr/Al 2 O 3 +TiO 2 catalyst. All the above factors had positive effects on the low-temperature SCR. However, Co-doping in Mn–Ce–Cr catalysts could not improve the pore structures or promote the dispersions of Mn–Ce–Cr active substances on the carrier surface. Groups such as nitrates and nitrites produced by NO adsorption would hinder the adsorption of NH 3 and low-temperature SCR. Mn–Ce–Cr/Al 2 O 3 +TiO 2 catalyst had high low-temperature SCR activity, while Mn–Ce–Cr/ZrO 2 catalyst was the most unstable with the lowest denitration efficiency. Moreover, for the scrapped catalyst from coal-fired power plants, it could still be used as the carrier of the Mn–Ce–Cr catalyst, and its SCR characteristics were much better than the above catalysts, especially at broader temperature range. | Study on Low-Temperature SCR Denitration Mechanisms of Manganese-Based Catalysts with Different Carriers | 10.1007/s11270-020-04644-5 |
2020-06-03 | Arc lower crust plays a critical role in processing mantle-derived basaltic melts into the intermediate continental crust, yet can only be studied indirectly or in exposed arc sections. Compared with the relatively well-studied oceanic arc sections (e.g., Kohistan and Talkeetna), the composition and formation mechanisms of continental arc lower crust remain less clear. Here we present a geochronological and geochemical study on the Lilong Complex and the Wolong granitoids from the Gangdese arc deep crustal section in southern Tibet. The Lilong Complex is composed of the early (85–95 Ma) mafic-intermediate sequence and late (85–86 Ma) ultramafic sequence. The Lilong crustal section exposed crustal depth extending from ~ 42 to 17 km based on the geobarometry. The mafic-intermediate sequence is a damp (low H 2 O) igneous differentiation sequence characterized by the subsequent appearance of pyroxene → plagioclase → amphibole → biotite. The ultramafic sequence represents a wet igneous differentiation sequence composed of olivine → pyroxene → amphibole → plagioclase. The 74–84 Ma Wolong granitoids were formed by fractional crystallization of wet magma and intra-crustal assimilation. Calculated seismic properties of the Gangdese deep arc crust are comparable to the average continental crust at a similar depth. The average composition of the Gangdese arc lower crust is basaltic andesite with SiO 2 of ~ 54 wt%. The highly incompatible elements in the Gangdese arc lower crust are systematically higher than those of the oceanic arc and are comparable with the estimates of lower continental crust, suggesting continental arc magmatism significantly contributes to the formation of continental crust. | Formation and composition of the Late Cretaceous Gangdese arc lower crust in southern Tibet | 10.1007/s00410-020-01696-y |
2020-06-03 | The Solar Heat Gain Coefficient (SHGC) is one of the energy loss factors in buildings, which affects a cooling load significantly. A variety of shading devices and high-performance windows have already been developed and applied to a large number of buildings to reduce a cooling load. However, performance evaluation on these shading devices and high-performance windows has depended on calculation via mathematical models and simulations. These evaluation methods have limits when reflecting heat characteristics of the ever-increasing complexity and development of window systems accurately in a realistic way. Thus, it is critically necessary to verify performance evaluation results through actual measure. The purpose of this paper is to measure the SHGC of various types of windows and shading devices and to analyze the difference between the calculated value and the measured value. The experimental result is as follows. SHGC of venetian blind is lower than SHGC of roll screen and Triple shade. The higher the glass SHGC was, the higher the SHGC reduction rate was under the same condition. The larger the slot angle was, the greater the SHGC performance improved. The analysis result on measured and calculated values showed that a mean different ratio was 4.86 %, which was matched within 5 % of the deviation rate. However, the different ratio tended to increase as the complexity of structures and types of windows increased. | Study on SHGC Calculation and Measurement of Window Installed with Shading Device | 10.1007/s10765-020-02684-x |
2020-06-02 | The production of electrical energy has always been a subject of debate to fight against climate change and preserve natural resources. Several countries, including Morocco, have proposed ambitious policies to develop renewable energy sources of production in the short and medium term. The major problem of renewable sources production is their intermittent nature. Using storage units, particularly PETS’ and molten salt technologies, will increase the penetration rate of renewable energies. The balance between production and consumption will optimize production, and it represents an important aspect of smart grids. In this article, an electrical energy consumption prediction was developed for the period 2019-2025, and optimization of the renewable energies injected within the grid was made by introducing the algorithm used. The results show that the use of storage units will increase the rate of renewable energies integration to 47.189% of the total installed capacity. | Optimal renewable resources mix for low carbon production energy system in Morocco | 10.1186/s42162-020-00105-9 |
2020-06-01 | Introduction The high-energy photon source, which has been built in Huairou, Beijing, has high requirements on magnetic field dithering. Magnetic field dithering is mainly determined by the stability of the output current of the power supply. In order to ensure the stability of the output current of quadrupole magnet power supply, the power supply sampling control loop needs to be precisely designed. In this paper, a precision ADC sampling system based on internal temperature control is designed to carry out precise control of the sampling ADC. Materials In this design, precise ADC chip is used to complete the precise sampling of the system. The precise sampling system contains a DAC system for high-speed settings. Methods In order to verify the design of the system, high-precision quadrupole magnet power supply is used for measurement. Conclusion The experimental results show that the temperature variation range of precision temperature control ADC system is ± 0.1 °C. By using the precise temperature control ADC system, the output current stability of the high-precision quadrupole magnet power supply is effectively improved. | A precision ADC sampling system design | 10.1007/s41605-020-00168-y |
2020-06-01 | This study was aimed at investigating the effect of novel ultrasonic-microwave combined pretreatment on the three-dimensional (3D) printing quality of wheat starch-papaya system. In this study, microwave heating (MH) and ultrasonic- microwave combined heating (UMCH) were used as pretreatment in order to gelatinize the system so that it can be printed. During the heating process, the effects of different pretreatments (MH and UMCH) and different low microwave power (60 W, 70 W and 80 W) were compared in terms of the gelatinization degree, rheological properties, dielectric properties, water status distribution, texture, microstructure and printing accuracy. The results showed that when the microwave power was 80 W, the printing effect of samples pretreated by UMCH was the best. Its support stability, line uniformity, and height retention were relatively at an optimum level. | Effect of Novel Ultrasonic- Microwave Combined Pretreatment on the Quality of 3D Printed Wheat Starch-Papaya System | 10.1007/s11483-019-09615-w |
2020-06-01 | Hollow glass microsphere (HGM) /organic silicon resin composite materials with different quantity of HGM were prepared by in-situ hydrolytic polymerization. The hydrolysis reaction of silicone resin was carried out at the same time with the surface treatment of HGM by the silane coupling agent. It has been found that HGM was treated by silane coupling agent and the silicone resin was hydrolyzed on the surface of HGM. Such in-situ polymerization method solves the poor compatibility between HGM and silicone resin. And then the composite materials were cured by hydrosilylation. The composite material has low dielectric constant (2.40) and good heat resistance. Such new HGM/organic silicone resin composite material is expected to be used for integrated circuit packaging material. | Preparation of Hollow Glass Microsphere/Organic Silicone Resin Composite Material with Low Dielectric Constant by In-Situ Polymerization | 10.1007/s12633-019-00234-1 |
2020-06-01 | This paper compares the techno-economic performances of three technologies for CO 2 capture from a lignite-based IGCC power plant located in the Czech Republic: (1) Physical absorption with a Rectisol-based process; (2) Polymeric CO 2 -selective membrane-based capture; (3) Low-temperature capture. The evaluations show that the IGCC plant with CO 2 capture leads to costs of electricity between 91 and 120 € · MWh −1 , depending on the capture technology employed, compared to 65 € · MWh −1 for the power plant without capture. This results in CO 2 avoidance costs ranging from 42 to 84 € · $${\text{t}_{{\text{CO}_2},\text{avoided}}}^{ - 1}$$ t CO 2 , avoided 1 , mainly linked to the losses in net power output. From both energy and cost points of view, the low-temperature and Rectisol based CO 2 capture processes are the most efficient capture technologies. Furthermore, partial CO 2 capture appears as a good mean to ensure early implementation due to the limited increase in CO 2 avoidance cost when considering partial capture. To go beyond the two specific CO 2 -selective membranes considered, a cost/membrane property map for CO 2 -selective membranes was developed. This map emphasise the need to develop high performance membrane to compete with solvent technology. Finally, the cost of the whole CCS chain was estimated at 54 € · $${\text{t}_{{\text{CO}_2},\text{avoided}}}^{ - 1}$$ t CO 2 , avoided 1 once pipeline transport and storage are taken into consideration. | Techno-economic comparison of three technologies for pre-combustion CO2 capture from a lignite-fired IGCC | 10.1007/s11705-019-1870-8 |
2020-06-01 | Abstract The tensile curves of ultrafine-grained (UFG) aluminum structured by high pressure torsion (HPT) technique have been obtained at 4.2 and 77 K for the first time as well as the temperature dependence of its yield strength in the range 4.2–300 K. The analysis of the results in correlation with microstructure parameters and comparison with the results of such studies for UFG aluminum structured by equal-channel angular pressing (ECAP) technique has been performed. It has been shown that the HPT-processed aluminum has a significantly higher yield strength at low temperatures than the ECAP-processed aluminum. Combination of high strength and plasticity (440 MPa and 55%, respectively) was obtained at 4.2 K, which makes this material attractive for practical use at low temperatures. The analysis of the obtained results indicates that, at room and low (77 K) temperatures, the plasticity of the UFG aluminum with a grain size less than 1 μm largely depends on the nature of the grain size distribution, as well as on the type and state of the grain boundaries (equilibrium or nonequilibrium), which opens up prospects for controlling the value of plasticity by creating a given microstructural design while maintaining a high level of strength of ultrafine-grained materials. | Mechanical Properties of Ultrafine-Grained Aluminum in the Temperature Range 4.2–300 K | 10.1134/S1063783420060190 |
2020-06-01 | The promotion of China’s coal gasification industry has produced highly yielded coal gasification slag. This research utilized the coal gasification fine slag as raw material and successfully synthesized a carbon–silica composite mesoporous material with a specific surface area of 500 m 2 /g and pore volume of 0.54 cm 3 /g by simple acid leaching technology. The influence of reaction conditions on porosity was discussed in detail, and the optimal sample was characterized by N 2 adsorption/desorption analyzer, SEM, TEM and others. Also, by the methylene blue adsorption experiment, we confirmed that the maximum adsorption capacity of synthesized mesoporous material is 182.48 mg/g, showing that it can be envisioned as a competitive candidate for purification of textile industrial wastewater. | Low-Cost Route for Preparing Carbon–Silica Composite Mesoporous Material from Coal Gasification Slag: Synthesis, Characterization and Application in Purifying Dye Wastewater | 10.1007/s13369-020-04383-z |
2020-06-01 | Intermetallic compounds, such as iron aluminides exhibit excellent oxidation and corrosion resistance, as well as metallurgical bonding with excellent adhesion to the substrate. In this work, aluminizing treatments were carried out using the dipping into slurry process to produce iron aluminide coatings on stainless steel substrates. In this process, AISI 304 stainless steel samples were immersed in a slurry consisting of polyvinyl butyral, ethyl alcohol and a powder composed of Al, AlCl 3 and Al 2 O 3 , dried and then placed in sealed crucibles without further protection. These samples were treated at temperatures of 500 and 650 °C for 2, 4, 6 and 8 h and then air-cooled. Flat and homogeneous layers were obtained over the substrate with increased thickness observed with increasing temperature and treatment time. Considering that the traditional treatments of aluminization by the pack process are carried out at temperatures close to 900 °C and use larger amounts of material, the low temperature treatments used in this work offer potential cost savings. | Production of Aluminide Layers on AISI 304 Stainless Steel at Low Temperatures Using the Slurry Process | 10.1007/s11665-020-04748-3 |
2020-06-01 | Fatigue assessment of welded joint is still far from being completely solved now, since many influencing factors coexist and some important ones should be considered in the developed life prediction models reasonably. Thus, such influencing factors of welded joint fatigue are firstly summarized in this work; and then, the existing life prediction models are reviewed from two aspects, i.e., uniaxial and multiaxial ones; finally, significant conclusions of existing experimental and theoretical researches and some suggestions on improving the fatigue assessment of welded joints, especially for the low-cycle fatigue with the occurrence of ratchetting, are provided. | Review on fatigue life prediction models of welded joint | 10.1007/s10409-020-00957-0 |
2020-06-01 | This work demonstrates the systematic investigation of the effects of high temperature on key performance parameters including speed, sensitivity, stability, and repeatability of a 3C-SiC/Si ultraviolet (UV) photodetector (PD) at various operating temperatures ranging from 50°C to 200°C. The device with very low dark current (∼ 0.08 pA) exhibited high sensitivity of 4466 and fast rise and decay times of 0.34 s and 0.30 s at 50°C to exposure of 254 nm UV light at a bias voltage of 20 V. Additionally, the device showed very good performance at a low operating voltage of 0.5 V and high temperature of 200°C, with a rise time of 2.68 s and decay time of 1.44 s, while maintaining good stability and repeatability. The slight decrease in performance (sensitivity from 4466 to 932) at 200°C was attributed to the increase in lattice scattering at elevated temperatures, leading to a decrease in carrier mobility. Moreover, the device was fabricated using a very cost-effective process flow. Consequently, this study can contribute to the development of low-power, fast, highly sensitive, and cost-effective 3C-SiC UVPDs for use in high-temperature photonic applications. | Low-Power-Operating 3C-SiC Ultraviolet Photodetector for␣Elevated Temperature Applications | 10.1007/s11664-020-08097-8 |
2020-06-01 | The Shanghai Meishan Iron and Steel Co., Ltd. has a large supply of coke oven gas (COG) and has the potential to develop and apply the spraying of COG on the surface of a sinter bed. The effects of the amount of COG, the spraying time, and the spraying distribution with the process on the quantity and quality indexes of sinter were investigated in the laboratory experiments. The results showed that the COG spraying can improve the sinter indexes to a large extent if appropriate parameters were used. It was found that an appropriate amount of COG, a relatively long spraying time, and a decreasing distribution of the COG amount with the spraying process all help to obtain a better performance for sinter quantity and quality indexes. When the COG spraying was applied to the No. 3 sintering machine, the sinter tumbler index increased by 0.45%, the overall finished product rate increased by 0.72%, the solid fuel consumption decreased by 4.06 kg/t, the reducibility increased by 3.89%, and the cost of iron decreased by 5.29 CNY/t, and the CO 2 , SO 2 and NO x emissions also decreased, thus proving the feasibility of this technology. Therefore, COG spraying provides a new way to improve sinter and also decrease the energy consumption and pollution. | Development and application of coke oven gas spraying on sinter bed | 10.1007/s42243-020-00403-2 |
2020-06-01 | A warm stamping process of 1 and 1.2 GPa ultra-high strength steel sheets at comparatively low temperatures using rapid resistance heating was investigated to produce high strength parts. The effects of the heating temperature and rate on mechanical and surface properties of warm-stamped parts were examined. For a rapid heat rate of 100 °C/s around a heating temperature of 300 °C, the hardness of the formed parts increased from that of the as-received sheets, and the hardness for the 1.2 GPa sheet approached that of conventional hot-stamped parts from 22MnB5 steel sheets. The increase in hardness appeared only for rapid heating, and not for slow heating using a furnace. The increase in hardness is due to the transformation of retained austenite into martensite at comparatively low temperatures using rapid resistance heating and cooling. For the comparative low heating temperature, the non-coated sheet hardly oxidised, and the galvannealed sheet having high corrosion resistance did not exhibit the exfoliation of the coating layer, whereas the springback did not improve. | Warm stamping of ultra-high strength steel sheets at comparatively low temperatures using rapid resistance heating | 10.1007/s00170-020-05642-x |
2020-06-01 | Hydrogen metallurgy is a technology that applies hydrogen instead of carbon as a reduction agent to reduce CO 2 emission, and the use of hydrogen is beneficial to promoting the sustainable development of the steel industry. Hydrogen metallurgy has numerous applications, such as H 2 reduction ironmaking in Japan, ULCORED and hydrogen-based steelmaking in Europe; hydrogen flash ironmaking technology in the US; HYBRIT in the Nordics; Midrex H 2 ™ by Midrex Technologies, Inc. (United States); H 2 FUTURE by Voestalpine (Austria); and SAL-COS by Salzgitter AG (Germany). Hydrogen-rich blast furnaces (BFs) with COG injection are common in China. Running BFs have been industrially tested by AnSteel, XuSteel, and BenSteel. In a currently under construction pilot plant of a coal gasification-gas-based shaft furnace with an annual output of 10000 t direct reduction iron (DRI), a reducing gas composed of 57vol% H 2 and 38vol% CO is prepared via the Ende method. The life cycle of the coal gasification—gas-based shaft furnace—electric furnace short process (30wt% DRI + 70wt% scrap) is assessed with 1 t of molten steel as a functional unit. This plant has a total energy consumption per ton of steel of 263.67 kg standard coal and a CO 2 emission per ton of steel of 829.89 kg, which are superior to those of a traditional BF converter process. Considering domestic materials and fuels, hydrogen production and storage, and hydrogen reduction characteristics, we believe that a hydrogen-rich shaft furnace will be suitable in China. Hydrogen production and storage with an economic and large-scale industrialization will promote the further development of a full hydrogen shaft furnace. | Development and progress on hydrogen metallurgy | 10.1007/s12613-020-2021-4 |
2020-06-01 | Triisopropanolamine (TIPA) was used as an early strength component to study its effects on mortar strength, cement paste setting time and early hydration characteristic of cement. And the early strength mechanism of TIPA at low temperature of 5 °C was also discussed. The results showed that, at 5 °C, the incorporation of TIPA promoted the condensation of cement paste, shortened the initial and final setting time, and accelerated the strength development of specimens at all ages, among which the strength after 3 d increased significantly. The 1, 3, 7, and 28 d compressive strength ratios of the mortars mixed with 1% TIPA could reach 196%, 179%, 160% and 110% respectively, and the mortar strength after 3 d exceeded that of the contrast sample cured at 20 °C. Under low temperature condition, TIPA could promote the hydration reaction of cement, shorten the induction period and advance the acceleration period. Furthermore, the maximum heat release rate and cumulative heat release quantity would be all increased, and the cumulative heat release of the cement mixed with TIPA hydrated for 12 h and 7 d increased 73% and 38% respectively. TIPA could shorten the nucleation and crystal growth (NG) stage and increase its hydration degree significantly, so it promoted cement hydration reaction. Additionally, the hydration reaction rates in phase boundary reaction (I) phase and diffusion reaction (D) phase were increased, and the duration of I process was prolonged, thereby the development of specimen strength would be accelerated. TIPA did not obviously change the types of hydration products, but increased the content of Ca(OH) 2 in the samples and the degree of cement hydration. After hydration to 7 d, large amounts of hydration products, whose surface was smooth, were formed and bonded into sheets, and the structural density of samples improved significantly. | Effect of Triisopropanolamine on the Compressive Strength and Early Hydration of Cement at Low Temperature | 10.1007/s11595-020-2298-1 |
2020-06-01 | Key messages Thirty MaFLAs vary in their molecular features. MaFLA14/18/27/29 are likely to be involved in banana chilling tolerance by facilitating the cold signaling pathway and enhancing the cell wall biosynthesis. Abstract Although several studies have identified the molecular functions of individual fasciclin-like arabinogalactan protein (FLA) genes in plant growth and development, little information is available on their involvement in plant tolerance to low-temperature (LT) stress, and the related underlying mechanism is far from clear. In this study, the different expression of FLAs of banana ( Musa acuminata ) ( MaFLAs ) in the chilling-sensitive (CS) and chilling-tolerant (CT) banana cultivars under natural LT was investigated. Based on the latest banana genome database, a genome-wide identification of this gene family was done and the molecular features were analyzed. Thirty MaFLAs were distributed in 10 out of 11 chromosomes and these clustered into four major phylogenetic groups based on shared gene structure. Twenty-four MaFLAs contained N-terminal signal, 19 possessed predicted glycosylphosphatidylinositol (GPI), while 16 had both. Most MaFLAs were downregulated by LT stress. However, MaFLA14/18/29 were upregulated by LT in both cultivars with higher expression level recorded in the CT cultivar. Interestingly, MaFLA27 was significantly upregulated in the CT cultivar, but the opposite occurred for the CS cultivar. MaFLA27 possessed only N-terminal signal, MaFLA18 contained only GPI anchor, MaFLA29 possessed both, while MaFLA14 had neither. Thus, it was suggested that the accumulation of these FLAs in banana under LT could improve banana chilling tolerance through facilitating cold signal pathway and thereafter enhancing biosynthesis of plant cell wall components. The results provide background information of MaFLAs , suggest their involvement in plant chilling tolerance and their potential as candidate genes to be targeted when breeding CT banana. | Genome-wide analyses of banana fasciclin-like AGP genes and their differential expression under low-temperature stress in chilling sensitive and tolerant cultivars | 10.1007/s00299-020-02524-0 |
2020-06-01 | All-optical devices, which are utilized to process optical signals without electro-optical conversion, play an essential role in the next generation ultrafast, ultralow power-consumption optical information processing systems. To satisfy the performance requirement, nonlinear optical materials that are associated with fast response, high nonlinearity, broad wavelength operation, low optical loss, low fabrication cost, and integration compatibility with optical components are required. Graphene is a promising candidate, particularly considering its electrically or optically tunable optical properties, ultrafast large nonlinearity, and high integration compatibility with various nanostructures. Thus far, three all-optical modulation systems utilize graphene, namely free-space modulators, fiber-based modulators, and on-chip modulators. This paper aims to provide a broad view of state-of-the-art researches on the graphene-based all-optical modulation systems. The performances of different devices are reviewed and compared to present a comprehensive analysis and perspective of graphene-based all-optical modulation devices. | Graphene-based all-optical modulators | 10.1007/s12200-020-1020-4 |
2020-06-01 | By the combination of transmission electron microscope, neutron diffraction and small-angle neutron scattering methods, mechanical fatigue behavior of AL6XN austenitic stainless steel was investigated in the temperature range of 400–600 °C. At 400 °C, in addition to the occurrence of dynamic strain aging, the formation of short-range order was evidenced from the forbidden electron diffraction spot of 1/3 {422} in face-centered cubic (fcc) structure viewed down [111] zone axis, which facilitate the planar slip mode of dislocation and result in the work hardening during the fatigue deformation. The fatigue damage is mainly dominated by the accumulation of planar slip band and the interaction among various slip systems. With increasing temperature, precipitates of chi phase, Laves phase and sigma phase were formed during the fatigue tests at 500 and 600 °C. An increase in precipitation content at 600 °C has also been confirmed by both scanning electron microscope and small-angle neutron scattering analysis. The dislocation pileup originating from the uncoordinated deformation between precipitate and austenitic matrix is an important fatigue damage leading to crack. The continuous cycle softening behavior was also observed on the fatigue curve at 600 °C, which is considered to be caused by dynamic recovery. | Fatigue Damage Mechanism of AL6XN Austenitic Stainless Steel at High Temperatures | 10.1007/s40195-020-01020-4 |
2020-06-01 | Sn-based Babbitt coatings are widely used for sliding in hydrodynamic bearings. The Babbitting of bearing surfaces is among others accomplished by casting; however, this implies some disadvantages such as segregations, or susceptibility to shrinkage defects. Thermal spraying represents a promising method to overcome these challenges. To date, no studies on Babbitt coatings deposited by means of low-pressure cold spraying (LPCS) are available in the literature. In this study, a first attempt is made to produce a Sn-Sb-Cu-based composite coating reinforced with alumina particles by means of LPCS which enables the coating of internal diameters (IDs) of cylindrical components. A tailor-made feedstock was utilized which consists of a powder mixture of Sn, Sb, Cu and alumina. The composite coating is investigated with regard to its microstructural and tribological characteristics using scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), as well as dry sliding experiments. Metallographic investigations demonstrate the feasibility of depositing an alumina-reinforced Sn-Sb-Cu-based composite coating with a dense microstructure and low porosity. The composite coating mainly consists of Sn, SbSn, Cu and hexagonal CuSn. Despite a small fraction of alumina particles, the microhardness of the composite coating is primarily determined by the formation of SbSn intermetallic phases dispersed in the soft Sn-Sb-rich matrix. The composite coating possesses a coefficient of friction of 0.43 ± 0.01 and wear coefficient k of 17.27 ± 7.77 × 10 −5 mm 3 N m −1 sliding against a 100Cr6 counterbody. | Microstructural and Tribological Characteristics of Sn-Sb-Cu-Based Composite Coatings Deposited by Cold Spraying | 10.1007/s11666-020-01054-1 |
2020-06-01 | Additive manufacturing (AM) is becoming increasingly popular since it offers flexibility to produce complex designs with less tooling and minimum material at shorter lead times. Wire arc additive manufacturing (WAAM) is a variant of additive manufacturing which allows economical production of large-scale and high-density parts. The WAAM process has been studied extensively on different steels; however, the influence of process parameters, specifically wire feed speed (WFS), travel speed (TS), and their ratio on bead geometry, microstructure, and mechanical properties, are yet to be studied. The present work aims at closing this gap by using the WAAM process with robotic cold metal transfer (CMT) technology to manufacture high-strength structural steel parts. For that purpose, single-bead welds were produced from HSLA steel by varying WFS between 5 and 10 m/min and the WFS to TS ratio between 10 and 20. Those variations produce heat inputs in the range of 266–619 J/mm. The results have shown that the wire feed speed to travel speed ratio is the major parameter to control the heat input. Increasing heat input increases characteristic bead dimension, whereas it reduces the hardness. In the second part of experiments, two single-bead walls were deposited via the parallel deposition strategy and one multiple-bead wall was produced using the oscillation strategy. The tensile properties were tested along two directions: parallel and perpendicular to deposition directions. For the yield strength and tensile strength, the difference between horizontally and vertically tested specimens was smaller than the standard deviations. On the other hand, the total and uniform elongation values exhibit up to 10% difference in the test direction, indicating anisotropy in ductility. Those tensile properties were attributed to repeated thermal cycles during the WAMM process, which can cause heat transfer in multiple directions. The yield strength of the multiple-bead wall produced via oscillation was lower, whereas its ductility was higher. The tensile properties and hardness differences were found to correlate well with the microstructure. | Wire arc additive manufacturing of high-strength low alloy steels: study of process parameters and their influence on the bead geometry and mechanical characteristics | 10.1007/s00170-020-05482-9 |
2020-06-01 | Abstract Cyclic heat treatment of steel samples is considered as a means of increasing their abrasive wear resistance. Cyclic heating of 65Г steel parts to 450°С increases their wear resistance by 40% in comparison with traditional inductive quenching. | Improving the Wear Resistance of Gear Teeth by Cyclic Quenching with Inductive Heating | 10.3103/S1068798X20060064 |
2020-06-01 | The solidus and liquidus temperatures and fusion heat were investigated in [(0.54NaF–0.46AlF 3 ) eut -(0.55KF–0.45AlF 3 ) eut ]-quasi-binary system. Two maximum liquidus temperatures (~ 1000 K) were observed at KF/(KF + NaF) ratio equal to 0.15 and 0.65. The minimum liquidus temperature (~ 900 K) was observed at KF/(KF + NaF) ratio equal to 0.3. The solidus temperatures were related to complex compounds KAlF 4 and K 2 NaAl 3 F 12 . The heat of fusion of eutectic compositions was found to be directly proportional to melting point. Thermal diffusivity of two eutectic mixtures was studied by laser flash method in temperature interval 300–800 K. Thermal conductivity was calculated using density and heat capacity data obtained for the same mixtures. Both thermal diffusivity and thermal conductivity are reduced with temperature for samples investigated. Thermal conductivity of potassium eutectic changes from 2.3 at 300 K to 1.8 W∙m −1 ∙K −1 773 K, and that of sodium eutectic reduces from 1.65 W∙m −1 ∙K −1 at 300 K to1.45 W∙m −1 ∙K −1 at 773 K. | Thermophysical properties of [(0.54NaF – 0.46AlF3)eut - (0.55KF – 0.45AlF3)eut]-quasi-binary system | 10.1007/s11581-020-03454-3 |
2020-06-01 | Understanding of thin film growth mechanism is crucial for tailoring film growth behaviors, which in turn determine physicochemical properties of the resulting films. Here, vapor-growth of tungsten carbide overlayers on W(110) surface is investigated by real time low energy electron microscopy. The surface growth is strongly confined by surface steps, which is in contrast with overlayer growth crossing steps in a so-called carpet-like growth mode for example in graphene growth on metal surfaces. Density functional theory calculations indicate that the step-confined growth is caused by the strong interaction of the forming carbide overlayer with the substrate blocking cross-step growth of the film. Furthermore, the tungsten carbide growth within each terrace is facilitated by the supply of carbon atoms from near-surface regions at high temperatures. These findings suggest the critical role of near-surface atom diffusion and step confinement effects in the thin film growth, which may be active in many film growth systems. | Step-confined thin film growth via near-surface atom migration | 10.1007/s12274-020-2769-x |
2020-06-01 | Abstract— The heat capacity C p ( T ) of cadmium fluoride, strontium fluoride, and the Cd 0.5 Sr 0.5 F 2 solid solution has been studied experimentally (2–300 K). We have detected deviations Δ C p ( T ) of the C p ( T ) data from additivity. The low-temperature (2–50 K), positive deviations Δ C p ( T ) have been tentatively attributed to the effect of two-level systems associated with the glasslike character of the low-temperature thermal properties of the solution due to disorder in the Cd–Sr sublattice. The high-temperature (100–300 K), negative deviations Δ C p ( T ) are caused by the effect of anharmonicity of lattice vibrations, whose increasing role is also associated with the disordered arrangement of atoms in the crystal lattice upon formation of the solution. The C p ( T ) data for the solution of the system studied have been analyzed in the Debye–Einstein model. We have determined model parameters: characteristic temperatures Θ i and the fractions of different contributions, a i , to total thermal characteristics of the substances studied. | Structural Disorder and Heat Capacity of a Solid Solution between Cadmium and Strontium Fluorides | 10.1134/S0020168520060096 |
2020-06-01 | Waterflooding has been applied for many years as secondary recovery method with no or little regard to the effect of the injected water salinity on oil recovery. However, in the last decade, there has been an increasing interest in understanding the effects of changing injected water salinity on reservoir performance. The potential of low-salinity waterflooding (LSWF) has been studied in sandstone reservoirs by numerous core-flooding experiments. These experiments have shown diverse results. This paper aims to investigate the effects of changing water salinity on oil recovery. A comprehensive review and analysis of the results of more than 500 core-flood experiments from published work were investigated to study the effects of several parameters such as clay content, clay type, and temperature on oil recovery. The relation between incremental oil recovery and sodium adsorption ratio SAR, and exchangeable sodium percentage (ESP) parameters which control clay swelling was illustrated. The analysis of the results revealed that there is an optimum composition and optimum salinity for waterflooding in secondary flooding stage. However, for tertiary flooding stage, the results showed that the controlling factor may be not decreasing the salinity but rather changing the salinity (e.g., either increasing or decreasing) with minor improvement in oil recovery. It was clear also that applying the optimum salinity in the secondary recovery stage is more effective than applying it in the tertiary recovery stage. This study aims to develop important guidelines for screening and designing optimum salinity for waterflooding projects in sandstone reservoirs. | Comprehensive investigation of low-salinity waterflooding in sandstone reservoirs | 10.1007/s13202-020-00862-z |
2020-06-01 | Low-cycle fatigue (LCF) behavior of a thermomechanically treated Fe 500 grade rebar has been evaluated under high-strain ranges to understand its seismic performance. The total strain-controlled LCF tests have been performed at five different strain (1.0, 2.0, 3.0, 4.0 and 5.0%) ranges at ambient temperature until failure maintaining a constant true strain rate of 1 × 10 −3 s −1 and a fixed strain ratio of − 1. Fatigue data have been analyzed following strain-life relationship; while, macro- and micro-features of the failed specimens have been critically examined under SEM. Evaluation of fatigue behavior has been supplemented by microstructural characterization apart from measurements of hardness and tensile property. Continued cyclic softening has been observed till failure, and the cyclic yield strength is found to be significantly lower than the monotonic one. Cross-sectional microhardness measurements of rebar before and after fatigue reveals significant reduction in hardness specifically in the rim region with tempered martensite microstructure. The strain-life relationship accurately predicts the cyclic plastic behavior of the selected rebar which also exhibits non-Masing behavior. The fatigue crack is always found to initiate from the transverse rib root and propagates along the rim region following the rib. | High-Strain Low-Cycle Fatigue Behavior of Thermomechanically Treated Rebar | 10.1007/s11668-020-00911-z |
2020-06-01 | In the present study, a novel model is proposed to evaluate the lower flammability limit (LFL) of alkane diluted with CO 2 . The LFL model is based on flame phenomenon simulation (FS-LFL). The model consists of combustion, turbulence, and igniter models, which are used to characterise the combustion based on the chemical kinetics and CFD, which is not feasible with traditional methods. The flame simulation phenomenon was validated by contrast with experiment and same criterion of flammability limit in the experiment was adopted. The FS-LFL model was used to predict the LFLs of a propane-CO 2 mixture and propane at various temperatures. The model performance was analysed by comparing the results with experimental data and predictions obtained from existing methods. The AARDs between the predicted and experimentally determined LFLs of the propane-CO 2 mixture are 0.34%, 1.19%, and 1.35% at 30°C, 50°C, and 70°C, respectively. The model also has a good predictive power with respect to the LFLs of propane at initial temperatures ranging from 30°C-300°C, with an AARD of 2.10%. When the dilution of CO 2 is 90%, the model yields a better result due to the utilisation of the chemical kinetics mechanism. This result is instructive for the use of this method in the prediction of upper flammability limits. | A lower flammability limit prediction model of alkane-CO2 mixtures based on flame phenomenon simulation | 10.1007/s11431-019-1447-4 |
2020-06-01 | To increase the COP and volumetric capacity of hydrofluoroolefins while reducing the global warming potential (GWP) of hydrofluorocarbons (HFCs), four HFC/R1234yf mixtures with various compositions are compared with verified thermodynamic models. Results show that a lower R1234yf mass fraction leads to a higher mixture latent heat; R32/R1234yf has the highest pressures, the lowest pressure ratios and the biggest temperature glides. As the R1234yf mass fraction increases from 0.0 to 1.0, the cooling coefficient of performance (COP) first increases from 5.25 to 5.52 and later decreases to 5.30 for R32/R1234yf, while it decreases from 5.46, 5.63 and 5.30 to 5.29 for R134a/R1234yf, R152a/R1234yf and R161/R1234yf. The heating COP first increases from 3.90 to 4.00 and later decreases to 3.79 for R32/R1234yf, while it decreases from 3.84, 3.95 and 4.02–3.79 for others. Caused by different volumetric capacities, R32/R1234yf requires a compressor enlarged by 2.8 times, R134a/R1234yf and R152a/R1234yf requires little change on compressor size, while R161/R1234yf requires a compressor enlarged by 1.5 times. R32/R1234yf yields the highest discharge temperature, while R134a/R1234yf yields the lowest. R32/R1234yf shows the highest exergy COPs (ECOPs) when the R1234yf mass fraction is above 60% in cooling mode and 46% in heating mode. Otherwise, R152a/R1234yf performs the best in cooling model and R161/R1234yf performs the best in heating mode. Considering both GWP and efficiency, the optimal composition is 20/80% for R32/R1234yf, 10/90% for R134a/R1234yf and 100/0% for both R152a/R1234yf and R161/R1234yf. This study provides suggestions for the determination of optimal compositions of different HFC/R1234yf mixture refrigerants. | Energy and exergy performance comparison of different HFC/R1234yf mixtures in vapor-compression cycles | 10.1007/s10973-019-08909-y |
2020-06-01 | Abstract The research results of the effect of small additions of vanadium and nitrogen on the microstructure and mechanical and service properties of high-carbon steels for railway transport are presented. The data on industrial production of metal products from such steels are considered. Medium-carbon bainitic and martensitic steels with a fine structure microalloyed with vanadium and nitrogen have a unique set of properties: a combination of high values of strength, ductility, cold resistance, and endurance under fatigue loading, which will increase the resistance of rails during operation not only at low temperatures, but also under conditions of increased loads, in curves of a small radius and in the event of a risk of thermomechanical damage. | Transport Steels Microalloyed with Vanadium and Nitrogen | 10.3103/S0967091220060078 |
2020-06-01 | Abstract TEC-DT differential heat hardening technology is developed based on the process of digital control of air humidity by high-efficiency mixing of air flows and the water ejected by it. The wide-range cooling rate control (2–14°C/s) makes it possible to heat hardened rails made of different steels, such as carbon steels, with a wide range of carbon content, and microalloyed and alloyed steels, while achieving the level of properties required for rails of both general and special purposes (low-temperature reliability and increased wear resistance). The rails, differentially hardened by reheating, have a highly dispersed pearlite structure, and a high level of ductility, impact strength, fatigue strength, and survivability. | Development of an Innovative Digital Cooling Technology (Differential Heat Treatment) for EVRAZ NTMK Rails | 10.3103/S0967091220060042 |
2020-06-01 | The distillation behaviors of some fission product fluorides in LiCl–KCl system were investigated. For rare earth element, the corresponding decontamination factors (DFs) of Ce in 5 wt% CeF 3 –LiCl–KCl salts were over 100 at 1040 K and 13 Pa. For SrF 2, the very poor DFs was deduced for the presence of more volatile SrClF, while Zr 4+ was observed to complex easily with F − and Cl − , which affected its evaporation rate and the separation efficiency. F ion concentration in condensate salt was 1–2 level higher than the metal ion due to the stronger covalent band. | The distillation behavior of fluorides in LiCl–KCl molten salt | 10.1007/s10967-020-07153-1 |
2020-06-01 | Abstract Low-energy (50–200 eV) He and Ar ion irradiation of on Si/SiO 2 -based nanoporous materials is modeled with the use of the molecular dynamics method. The obtained results corroborate the experimentally observed effect of densification of near-surface layers of materials with small-size pores and low porosity due to the ion-induced pore collapse process. The differences in the He and Ar ion irradiation of nanoporous materials and the influence of ion energy on the intensity of structural changes are studied. | Features of Low-Energy He and Ar Ion Irradiation of Nanoporous Si/SiO2-Based Materials | 10.1134/S1063785020060140 |
2020-06-01 | In this work, five different hot-rolled steel strips with different microstructures were produced through different microalloying design and adjusting final coiling temperature. The relationship between microstructure and mechanical properties, especially fatigue limit, was analyzed in detail. The results showed that the steels with mainly quasi-polygonal ferrite and pearlite have a similar yield strength as the steels with acicular ferrite and martensite, but they are higher than the DP (ferrite + martensite) steels that are strengthened by the second martensite phase. This is probably because the yield strengths of fine ferritic steels are further enhanced by the precipitation strengthening mechanism of nano-sized particles. Under the present experimental conditions, the fatigue limit is proportional to yield strength rather than tensile strength. It is also found that the precipitation strengthening mechanism is more beneficial to improving the fatigue stress than the strengthening mechanism by introducing martensite, although all these steels have the same fatigue crack initiation mode. | Correlation of Microstructure and Fatigue Properties of Hot-Rolled Steel Strips for Automobile Structural Application | 10.1007/s11665-020-04889-5 |
2020-06-01 | High-strength low-alloy or microalloyed steels are thermo-mechanically control processed (TMCP) to achieve desired microstructures and mechanical properties, and microalloy additions are critical for obtaining optimum properties. The steel of interest in this study is microalloyed with approximately 0.1 wt% Nb, levels that are typical in pipeline steels such as X70. Submerged arc welding (SAW) is a commonly utilized manufacturing method for constructing pipe segments via seam welding. There were two parts to this investigation. Part 1 analyzed controlled dilution levels consisting of commercially available SAW electrodes and Nb-bearing steel in proportions to simulate submerged arc weld metal. Part 2 of this investigation evaluated actual submerged arc welds on low-alloy steels. Bead-on-plate welds were deposited, and the Nb content of the weld metal was systematically increased by adding ferro-niobium directly to the flux. Two-run welds representative of line pipe production were also evaluated using the same ferro-niobium flux additions in order to increase the weld metal Nb content. The microstructural evolution and corresponding mechanical properties with increased Nb are evaluated based on this work and on the published literature. | Effect of niobium on the microstructure and properties of submerged arc welds in HSLA steel | 10.1007/s40194-020-00900-8 |
2020-06-01 | Nanoblends of conjugated materials doped with low-dimensional metal oxides employing a scalable manufacturing process are discussed. The morphology, crystal structure and photocatalytic property of the nanoblends comprising of π-stacking materials namely polyaniline (PANI), polythiophene (PTh), graphene oxide (GO) doped with metal oxide Fe–TiO 2 to form Fe–TiO 2 /PANI, Fe–TiO 2 /GO and Fe–TiO 2 /PTh nanostructures were studied in detail. The process includes wet chemical synthesis of the inorganic counterparts followed by mash blending technique to procure the low-dimensional nanoblends. The optical absorption characteristics of the above samples were studied by UV spectra. Furthermore, the samples are characterized by XRD, FTIR, SEM-EDAX and TEM analysis. The obtained nanoblends were utilized as photocatalyst for hydrogen production and a rational comparison was made with the procured Fe–TiO 2 nanoblends. The assessment of the photocatalyst was also carried out. Among the prepared nanoblends, Fe–TiO 2 /PTh has good photocatalytic activity and shows maximum efficiency of 15.83% towards photocatalytic hydrogen production which can be ascribed to increased surface area as a result of texturing attributes. The long-term stability of the photocatalyst was confirmed by the catalytic stability tests. | Composites of π-stacking materials with low-dimensional metal oxide nanoblends for photocatalytic hydrogen production
| 10.1007/s40097-020-00339-9 |
2020-06-01 | In this study, the low-pressure carbonitriding (LPCN) response of four different steel alloys is investigated. The influence of unprotected boron is evaluated by comparing the microstructure and fatigue performance of 20MnCr5 with and without boron additions after LPCN. Similarly, the influence of Nb microalloying is assessed by comparing 8620 steel with and without Nb additions. Low-pressure carbonitriding heat treatments were developed to achieve case depths of 0.65-0.75 mm in each alloy, thus allowing the influence of alloying and microstructure to be explored independent of case depth. The hardness and case microstructure are correlated with bending fatigue response measured with Brugger fatigue specimens, which are designed to simulate the root of a gear tooth. The 20MnCr5 alloys had the highest fatigue strength, and the 8620 alloys had the lowest fatigue strength, despite having the same hardness profile and case depth. Reductions in prior austenite grain size and increased surface hardness appeared to have a positive effect on the endurance limit of the steel alloys. Retained austenite volume fraction on the surface of the steel alloys as well as non-martensitic transformation products subsurface in the case did not have an apparent direct contribution to fatigue performance. | Bending Fatigue in Low-Pressure Carbonitriding of Steel Alloys with Boron and Niobium Additions | 10.1007/s11665-020-04757-2 |
2020-06-01 | An oxadiazole derivative 4-[3-(4-methylphenyl)-1,2,4-oxadiazol-5-yl]-phenol (MOP) has been investigated as a protector against corrosion of mild steel tanks in Iraqi kerosene reservoirs using the Tafel approach. The extrapolation study was carried out in four temperatures (303, 313, 323 and 333 K) and five concentrations (100, 200, 300, 400 and 500 ppm) of MOP derivative. The results of the polarization study showed that the MOP inhibitor is classified as a mixed type and the activity of corrosion inhibition was estimated depending on Tafel curve. The highest performance of the inhibition efficiency (IE% = 88.95) was observed in 500 ppm of the MOP inhibitor at 303 K, and the results showed that the increase of IE% was related to increase in the temperature and concentration of the inhibitor. The calculated thermodynamic parameters confirmed that the nature of adsorption is physisorption and the inhibitor obeys Langmuir isotherm. Different morphological methodologies have been used to confirm the protected layer formation on the steel surface. Also, Fourier transform infrared (FT-IR) spectrophotometer was used to detect the interference method between the inhibitor and surface. The computational study was applied to show the active locations of inhibitor and study their relationship with the surface by density functional theory (DFT). Also, the biological efficacy of this inhibitor has been shown to have a good inhibition zone against some types of corrosive bacteria. | Electrochemical, morphological and theoretical studies of an oxadiazole derivative as an anti-corrosive agent for kerosene reservoirs in Iraqi refineries | 10.1007/s11696-019-01022-2 |
2020-06-01 | Poleward expatriation of tropical marine organisms is occurring globally, linked to climate change via strengthening of Western Boundary Currents (WBCs). In summer 2016, there was an unprecedented (in 18 years of monitoring) influx of coral-reef fish juveniles (“vagrants”) in temperate SE Australia. However, a large climate change-linked storm event (“East Coast low”) in June 2016 wiped out large numbers of these fishes over several days, as well as severely altering coastal habitat. Some taxa (e.g. Acanthuridae: surgeonfishes, key habitat modifiers) were decimated with up to 95% loss, while others (e.g. Pomacentridae: damselfishes, under 5% loss) fared better. The storm altered habitat (boulder “barens” were exposed by large-scale removal of macroalgae) with new barrens supporting over fifty times more tropical fish recruits in the following year (2017) than surrounding kelp-dominated areas. Fish were more vulnerable to storm effects in exposed habitats, and some species exhibited size-selective losses. Such climate-related storms can decouple links between poleward fish shifts and more predictable climate effects such as sea temperature rise. | Opposing climate-change impacts on poleward-shifting coral-reef fishes | 10.1007/s00338-020-01919-5 |
2020-06-01 | Aims/hypothesis Physical inactivity, low mitochondrial function, increased intramyocellular lipid (IMCL) deposition and reduced insulin sensitivity are common denominators of chronic metabolic disorders, like obesity and type 2 diabetes. Yet, whether low mitochondrial function predisposes to insulin resistance in humans is still unknown. Methods Here we investigated, in an intervention study, whether muscle with low mitochondrial oxidative capacity, induced by one-legged physical inactivity, would feature stronger signs of lipid-induced insulin resistance. To this end, ten male participants (age 22.4 ± 4.2 years, BMI 21.3 ± 2.0 kg/m 2 ) underwent a 12 day unilateral lower-limb suspension with the contralateral leg serving as an active internal control. Results In vivo, mitochondrial oxidative capacity, assessed by phosphocreatine (PCr)-recovery half-time, was lower in the inactive vs active leg. Ex vivo, palmitate oxidation to 14 CO 2 was lower in the suspended leg vs the active leg; however, this did not result in significantly higher [ 14 C]palmitate incorporation into triacylglycerol. The reduced mitochondrial function in the suspended leg was, however, paralleled by augmented IMCL content in both musculus tibialis anterior and musculus vastus lateralis, and by increased membrane bound protein kinase C (PKC) θ. Finally, upon lipid infusion, insulin signalling was lower in the suspended vs active leg. Conclusions/interpretation Together, these results demonstrate, in a unique human in vivo model, that a low mitochondrial oxidative capacity due to physical inactivity directly impacts IMCL accumulation and PKCθ translocation, resulting in impaired insulin signalling upon lipid infusion. This demonstrates the importance of mitochondrial oxidative capacity and muscle fat accumulation in the development of insulin resistance in humans. Trial registration ClinicalTrial.gov NCT01576250. Funding PS was supported by a ‘VICI’ Research Grant for innovative research from the Netherlands Organization for Scientific Research (Grant 918.96.618). | One-leg inactivity induces a reduction in mitochondrial oxidative capacity, intramyocellular lipid accumulation and reduced insulin signalling upon lipid infusion: a human study with unilateral limb suspension | 10.1007/s00125-020-05128-1 |
2020-06-01 | A biochar filter, in conjunction with a biosand filter, was used to remove environmentally relevant concentrations of synthetic organic chemical such as atrazine, anthracene, naphthalene and phenanthrene from creek water over a period of 36 days. The biochar filter achieved complete removal of anthracene and phenanthrene, and significant removal of atrazine and naphthalene at the beginning of the experiment. Atrazine removal was observed to be dependent on pause period/contact time (i.e., contact time between atrazine and the biochar in the filter) and declined over time. Longer pause period/contact time resulted in better removal of atrazine, though the same effect of contact time was not observed for anthracene, phenanthrene or naphthalene. Variation in the removal of atrazine along the length of the filter column was observed and atrazine removal for water samples collected near the top of the filter column was found to be the lowest. The possible desorption of the chemicals from the biochar media was investigated, results suggested possible leaching of atrazine from the biochar. Leaching of anthracene, naphthalene and phenanthrene was not observed. The biochar filter was shown to be a promising technology to remove synthetic organic compounds from drinking water and can be used in conjunction with a biosand filter for contaminant removal. | An intermittently operated biochar filter to remove chemical contaminants from drinking water | 10.1007/s13762-019-02615-w |
2020-06-01 | A combination of experimental measurements and numerical analysis was utilized to study the low-velocity impact damage of domestic carbon fiber-reinforced composites (CFRCs). The results indicated that the low-velocity impact damage induced pits and longitudinal cracks on the front side, oblique cracks and delaminationin on the back side. The pit depth increased with the increasing impact energy. It was demonstrated that the numerical analysis strain history curve was similar to the experimentally measured strain history curve, which verified the accuracy of numerical analysis in which the Hashin failure criterion was used. The work provides basic data and theoretical basis for the promotion and application of the domestic carbon fiber, and demonstrates the feasibility of replacing imported carbon fibers with domestic carbon fibers. | Influence of Low-velocity Impact on Damage Behavior of Carbon Fiber-reinforced Composites | 10.1007/s11595-020-2282-9 |
2020-06-01 | Optimization of grain boundary engineering (GBE) process is explored in a Fe–20Cr–19Mn–2Mo–0.82 N high-nitrogen and nickel-free austenitic stainless steel, and its intergranular corrosion (IGC) property after GBE treatment is experimentally evaluated. The proportion of low Σ coincidence site lattice (CSL) boundaries reaches 79.4% in the sample processed with 5% cold rolling and annealing at 1423 K for 72 h; there is an increase of 32.1% compared with the solution-treated sample. After grain boundary character distribution optimization, IGC performance is noticeably improved. Only Σ3 boundaries in the special boundaries are resistant to IGC under the experimental condition. The size of grain cluster enlarges with increasing fraction of low ΣCSL boundaries, and the amount of Σ3 boundaries interrupting the random boundary network increases during growth of the clusters, which is the essential reason for the improvement of IGC resistance. | Application of Grain Boundary Engineering to Improve Intergranular Corrosion Resistance in a Fe–Cr–Mn–Mo–N High-Nitrogen and Nickel-Free Austenitic Stainless Steel | 10.1007/s40195-020-01000-8 |
2020-06-01 | The transition zone water filter model (Nature 425(6953), 39–44; 2003) predicts that a hydrous partial melt layer is only actively produced in a region of upwelling mantle. We test the transition zone water filter model via stacking of P-to-S converted receiver functions by using the IRIS-PASSCAL RISTRA (Colorado Plateau/Rio Grande Rift Seismic Transect Experiment) array. Assuming the high velocity regions found at the northwest and southeast ends of the array at 350–440 km by teleseismic velocity tomograms e.g. Schmandt and Humphreys (Earth and Planetary Science Letters 297(3–4): 435–445; 2010 ) are cold and sinking vertically, the 410-km low velocity layer should be absent in these regions. The receiver function stacking profiles find the mean depths of the two primary discontinuities at 417 ± 7.1 km for the 410-km discontinuity and 667 ± 8.2 km for the 660-km discontinuity. The average arrival amplitudes with respect to Z component are 3.0% for the 410-km discontinuity, 2.8% for the 660-km discontinuity, and − 1.8% for the 410-km low velocity layer. The stacked P d s image show the 410-km low cabsent at ~ 350 to 390 km in the high velocity regions, but present in low velocity region. A correlation plot of sum of the 410-km low velocity arrival amplitudes and P-wave perturbation finds a positive linear relationship. Therefore, our findings provide seismic evidence for the transition zone water filter model at a small scale. | Correlation of a 410-km Discontinuity Low Velocity Layer with Velocity Tomograms Beneath the Colorado Plateau Using the RISTRA Array | 10.1007/s00024-019-02405-y |
2020-06-01 | CO 2 flooding has become one of most effective methods to improve oil recovery in low-permeability reservoirs. Thus, influencing factors have been specifically analyzed for their impact on oil displacement. Factors that are difficult to observe, such as capillary pressure and CO 2 dissolution, have often been neglected in specific analysis. To do so, this paper combined laboratory experimentation with numerical simulation analysis to understand the specific functions of capillary pressure and CO 2 dissolution in the CO 2 -flooding process in low-permeability reservoirs. Based on laboratory experiments with long cores applying different CO 2 -flooding methods, the authors established a one-dimensional numerical simulation model for CO 2 flooding. After that, the model was simulated to analyze the effects of capillary pressure and CO 2 dissolution for different CO 2 -flooding processes. The results show that the function of capillary pressure in different CO 2 -flooding modes is not consistent in low-permeability reservoirs; furthermore, capillary pressure is a driving force in the process of flooding and is a resistance force in the CO 2 -flooding process after pressure recovery. When considering CO 2 dissolution in different flooding modes, its function was shown to be inconsistent in low-permeability reservoirs compared with CO 2 flooding without considering CO 2 dissolution; oil recovery is reduced in the CO 2 -flooding process, but oil recovery increases in the CO 2 -flooding process after pressure recovery. Therefore, in order to promote the rational and effective development of low-permeability reservoirs, it is necessary to understand the functions of capillary pressure and CO 2 dissolution clearly in the process of CO 2 flooding. | Functions of capillary pressure and dissolution in the CO2-flooding process in low-permeability reservoirs | 10.1007/s13202-020-00853-0 |
2020-06-01 | The salinity effect on anammox bacteria has been widely reported; however, rare studies describe the microbial dynamics of anammox-based process response to the introduction of real seawater at mainstream conditions. In this study, an anammox process at mainstream conditions without pre-enriching anammox bacteria was shifted to the feeds of a synthetic wastewater with a portion of seawater mixture. It achieved over 0.180 kg-N/(m 3 day) of nitrogen removal rate with an additional seawater proportion of 20% in the influent. The bacterial biodiversity was significantly increased with the increase of seawater proportions. High relative abundance of anammox bacteria (34.24–39.92%) related to Ca. Brocadia was enriched and acclimated to the saline environment. However, the introduction of seawater caused the enrichment of nitrite-oxidizing Ca. Nitrospira , which was responsible for the deterioration of nitrogen removal efficiency. Possible adaptation metabolisms in anammox bacteria and other nitrogen transforming bacteria are discussed. These results highlight the importance of microbial diversity for anammox process under the saline environments of 20% and 40% seawater composition. | Evolution of microbial dynamics with the introduction of real seawater portions in a low-strength feeding anammox process | 10.1007/s00253-020-10598-9 |
2020-06-01 | Potassium (K) plays a pivotal role in carbon (C) and nitrogen (N) balance via several physiological processes. Conventional K application ratio (0.6–0.8) is too low to meet the optimal K requirement for physiological activities as well as yield benefits in cotton. However, in line with low N application, what is the optimal K ratio relative to N, for efficient C-N balance and its relationship with enzymes activities as well as yield, is the objective of this study. A pot experiment was conducted with three K ratio to N (K 1 (0.8), K 2 (1.0), and K 3 (1.2)) using completely randomized design at the experimental site of Huazhong Agricultural University, Wuhan, China. The morphological attributes, C-N enzyme activities, assimilate contents, and yield-related components were analyzed under different K ratios. Results showed that higher K application ratios (K 2 and K 3 ) significantly enhanced the yield, leaf morphological attributes (leaf area and leaf weight), and C- and N-metabolizing enzyme activities. Similarly, C and N assimilation compounds were effectively balanced in leaves of plants receiving K 2 and K 3 over K 1 leading to an appropriate C/N ratio. Conclusively, leaf K content, C-N compounds balance, and narrow C/N ratio in higher K application suggest that the K relative ratio should be equal or even higher than N application rate. However, from an economic point of view, results suggest that the K ratio equal to the N is sufficient to get promising cotton yield with late planting under reducing N rate. | Relative Potassium Ratio Balanced the Carbon-Nitrogen Assimilation in Cotton Leaf Under Reducing Nitrogen Application | 10.1007/s42729-019-00163-3 |
2020-06-01 | Bacterial cellulose (BC), an important biopolymer, has gained tremendous interest in several fields in the last few decades. Despite having the same chemical structure as plant cellulose, BC is superior in physical appearance and purity, as well as in mechanical, crystallinic, and biological properties for multiple applications. Despite these features, BC has limitations in production cost as well as physiological features. Notable limitations, including a non-bactericidal nature, low biocompatibility, and lack of conductive and magnetic properties, have been compensated through the development of composites using nanomaterials and polymers. Similarly, the limitation associated with cost has been reduced by developing new BC synthesis strategies, designing novel bioreactors, using genetically modified microbial species, and exploring alternative cheap fermentation media. Successful BC production has been reported from the use of industrial, confectionary, municipal and other wastes, including coconut water and fruit juices. Herein, we overview various efforts made thus far in identifying waste byproducts and inexpensive carbon sources for cost-effective BC production. It also provides information about the BC market and selling price, as well as techno-economic analysis of biotechnological BC production. This review article includes findings reported in the last few decades, and we hope it will be of great interest for readers as well as commercial BC producers. | Production of bacterial cellulose from alternative cheap and waste resources: A step for cost reduction with positive environmental aspects | 10.1007/s11814-020-0524-3 |
2020-06-01 | In the pandemic situation created by COVID-19, which is a fast spreading human-to-human transmittable disease, it is essential to protect health care providers. They are frontline warriors who fight this disease by treating patients and are most vulnerable to the same disease. In the current scenario, it is required to come up with innovative solutions to protect health care providers, such innovations should be made in to usable products with limited resources available due to lock down condition prevailing in the market and should be provided to them instantly. Main routes of infection of COVID-19 disease are, direct contact with objects that has virus on it and indirect contact by inhaling droplets emitted through sneezes and cough of patients. Healthcare providers can avoid direct contact with objects having virus by using proper PPE (Personal Protective Equipment). However, they are at risk of transmissions by microscopic aerosol particles consisting of the residual solid components of evaporated respiratory droplets, which are tiny enough (< 5 μm) to remain airborne for hours created by cough and sneeze. Authors have come with such a solution, called as ‘Aerosol Containment Box’ that act as barrier to safeguard health care providers from viral infection while performing medical procedures. It is made of transparent acrylic box, and covers COVID-19 patient from head up to chest. This box has to be placed on the body of the patient while he is being treated. This box is of low cost, can be made easily with limited resources and can be re-used after disinfection. This box is conceptualized, designed, manufactured, engineered and demonstrated within a record duration of 3 days. 100 nos of such boxes are made within 15 days and are distributed at various hospitals in Hyderabad. Engineering drawings and manufacturing process are documented and shared with outstation enthusiastic manufacturers. | Aerosol Containment Box | 10.1007/s41403-020-00140-8 |
2020-06-01 | This article addresses the technical and cost competitiveness of microfiltration and centrifugation to produce organic clarified bottle gourd juice. The microfiltration (MF) process was conducted for fresh and centrifuged juices and for transmembrane pressures ranging from 103.4 to 172.4 kPa. Pertinent flux decline was extensively analyzed to account for the extent of irreversible membrane fouling using resistances in series model, flux decline, and recovery ratios. Feed, centrifuged, and permeate juice samples were evaluated for nutritional content and physico-chemical parameters to affirm that MF of fresh juice is the best among all investigated cases. Compared with the centrifugation process, the MF process performed comparatively better in terms of cost competitiveness, juice clarity, microbial, and protein rejection. For a variation in juice production capacity of 110–10,000 L, the MF-based juice processing cost varied from 1.19 to 0.37 $/L, which accounts to 31.27–26.32% of fresh juice cost to infer upon promising performance of the low-cost ceramic membranes. | Feasibility of Low-Cost Kaolin–Based Ceramic Membranes for Organic Lagernaria siceraria Juice Production | 10.1007/s11947-020-02455-4 |
2020-06-01 | Since most coalfields in China are commonly characterized by high gas content and low permeability, there is an urgent need to improve coal seam permeability and further enhance coal bed methane (CBM) extraction efficiency. As an emerging fracturing technology, the CO 2 gas fracturing (CGF) technology has been widely used because of its advantages of low cost, environmental protection and high fragmentation efficiency. In order to improve the fracturing ability of CGF technique and optimize the release orifices of discharge head, computational fluid dynamics model was used in this paper to simulate the flow fields of dynamic pressure of gas jet released from the orifices with different structures and other geometrical parameters. The results show that the orifice structure has a great influence on the flow field of gas jet, but little influence on the magnitude of the dynamic pressure. Besides, the maximum dynamic pressure of gas jet linearly decreases with the increase in the number of release orifices. Based on a series of simulation results, the discharge head which has single group of orifices with structure c, diameter of 24 mm can be identified as the best choice for fieldwork. Then, two field experiments were conducted in Pingdingshan and Changping coal mines to evaluate the enhanced CBM extraction efficiency by CGF. The results indicate that the CGF can effectively create a large number of cracks in a large range around the fracturing borehole in the coal seam and further significantly improve the permeability. And the CBM extraction efficiency can be improved to a higher level from a lower level and maintained for a long time. Besides, the effective influence radii caused by CGF in Pingdingshan and Changping coal mines are 15.19 m and 12.5 m, respectively. Compared with other fracturing techniques, the CGF technique has a promising application prospect. | Optimization and Field Application of CO2 Gas Fracturing Technique for Enhancing CBM Extraction | 10.1007/s11053-019-09563-9 |
2020-06-01 | Abstract —Alkaline and subalkaline granites of the Keivy megablock belong to the potassic alkali-calcic ferroan rocks enriched in large-ion lithophile, high-field strength and rare-earth elements. Based on these criteria, they correspond to A 2 -type granites (Eby, 1992). The granites have elevated Y/Nb (1.9–2.5) and Yb/Ta (3.4–3.7) ratios typical of crustally derived granites. The initial 176 Hf/ 177 Hf ratios in the central parts of zircon crystals vary within 0.281004–0.281175 at εHf(T) ranging from –2.89 to 3.79. It is supposed that the underplating of high-temperature mafic melts caused melting of metasomatically altered lower-crustal rocks and formation of palingenetic lower-crustal melts, which during subsequent ascent in the upper crust experienced fractional crystallization to more siliceous subalkaline and alkaline melts. | Lu–Hf Isotope-Geochemical Zircon Systematics and Genesis of the Neoarchean Alkaline Granites in the Keivy Megablock, Kola Peninsula | 10.1134/S0016702920060129 |
2020-06-01 | Lithium (Li) metal is regarded as the holy grail anode material for high-energy-density batteries owing to its ultrahigh theoretical specific capacity. However, its practical application is severely hindered by the high reactivity of metallic Li against the commonly used electrolytes and uncontrolled growth of mossy/dendritic Li. Different from widely-used approaches of optimization of the electrolyte and/ or interfacial engineering, here, we report a strategy of in-situ cerium (Ce) doping of Li metal to promote the preferential plating along the [200] direction and remarkably decreased surface energy of metallic Li. The in-situ Ce-doped Li shows a significantly reduced reactivity towards a standard electrolyte and, uniform and dendrite-free morphology after plating/ stripping, as demonstrated by spectroscopic, morphological and electrochemical characterizations. In symmetric half cells, the in-situ Ce-doped Li shows a low corrosion current density against the electrolyte and drastically improved cycling even at a lean electrolyte condition. Furthermore, we show that the stable Li LiCoO 2 full cells with improved coulombic efficiency and cycle life are also achieved using the Ce-doped Li metal anode. This work provides an inspiring approach to bring Li metal towards practical application in high energy-density batteries. 锂金属由于其高理论比容量(3860 mA g −1 )而被认为是最具 潜力的高能量密度锂电池用负极材料. 然而, 锂枝晶的不可控生长 和金属锂对电解液的高反应活性严重阻碍了其实际应用. 区别于 以往广泛使用的电解液优化或界面修饰工艺, 本文采用一种原位 铈掺杂的策略, 从根本上改变了锂金属的电沉积行为. 通过锂电极 表面的原位铈掺杂促进锂在电化学过程中沿[200]方向优先沉积, 显著降低金属锂的表面能. 光谱、形貌和电化学测试等结果证明, 原位铈掺杂大大降低了锂电极对电解液的反应活性, 使得电极在 沉积/脱出过程中具有无枝晶形貌. 采用这种策略装配的对称电池 中, 锂电极具有低腐蚀电流密度, 甚至在贫液条件下循环寿命也得 到显著提升. 采用铈掺杂锂负极的锂-钴酸锂全电池可稳定循环300 周, 库伦效率和循环寿命得到明显提高. 本工作为金属锂负极在高 能量密度电池中的实用化研究提供了一种具有启发性的策略. | Stable Li metal anode by crystallographically oriented plating through in-situ surface doping | 10.1007/s40843-019-1277-3 |
2020-06-01 | Abstract The hydrocarbon composition of the thermolysis products of asphaltenes from biodegraded oils of the Labagan and Usa oilfields and non-biodegraded oil of the Salyukinskoe oilfield of the Timan–Pechora sedimentary basin has been studied. The IR spectra of the asphaltenes are identical, indicating their similar structural group composition. The thermolysis of the asphaltenes has been carried out in an argon flow successively at 300 and 350°C. It has been shown that desorption of saturated and aromatic components from the pores of the asphaltenes predominantly occurs at 300°C. For the initial biodegraded oils and the oil that did not undergo biochemical oxidation, a number of geochemical parameters calculated in terms of acyclic hydrocarbons (HCs) and polycyclic biomarkers turns out to be similar to those obtained for the thermolysis products of the asphaltenes heated at 350°C. The values of the methylphenanthrene index are similar for the thermolysis products of asphaltenes and the parent oils. This similarity, in turn, allows the genetic identification of oils and evaluation of their catagenetic maturity by asphaltene thermolysis products in the case when biomarkers of the aliphatic fraction are lost during biodegradation. An analysis of the supermolecular structure of the asphaltenes of the oils under study has shown a general trend of its change by heating at 350°C, which consists in a sharp decrease in the particle size and loosening of the particle packing due to the appearance of pronounced porosity. | Thermolysis of Asphaltenes of Timan–Pechora Heavy Oils | 10.1134/S0965544120060043 |
2020-06-01 | High-mobility low-hysteresis electrolyte-gated thin-film transistors were successfully fabricated using a diketopyrrolopyrrole (DPP) and benzotriazole (BTz) copolymer semiconductor and high-capacitance ion gels based on 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([EMI][TFSI]) and tetraoctyl phosphonium ([P 8888 ]) [TFSI]. The DPP-BTz transistors gated with both ion gels operated effectively at low voltages below 1V with high on-to-off current ratios exceeding 10 5 and very low device hysteresis. Specifically, when the [EMI][TFSI] ion gel was employed as a gate dielectric layer, the DPP-BTz transistors exhibited a very high carrier-mobility value of 8.50 ± 1.09 cm 2 /Vs. In addition, device hysteresis of the DPP-BTz transistor was almost invariant to the voltage sweeping rate and was much lower than that of the poly(3-hexylthiophene) (P3HT) transistor under the same conditions. Overall, these results indicate that the performance of electrolyte-gated transistors can be improved using the DPP-BTz semiconductor. | High-Mobility Low-Hysteresis Electrolyte-Gated Transistors with a DPP-Benzotriazole Copolymer Semiconductor | 10.1007/s13233-020-8120-2 |
2020-06-01 | Abstract Irradiation with accelerated electrons of an extraction mixture of 30% TBP in Isopar-M isoparaffin diluent on the lower temperature limit of flame propagation ( Т l ) has been studied. It was found that, under irradiation up to a dose of 2 MGy, the value of Т l of the extraction mixture may decrease to 45°С, which should be taken into account when organizing the technological process. It was shown that, when an irradiated extraction mixture is bubbled with air, the value of Т l nearly reaches the Т l of the starting solution. | Effect of Irradiation of the Extraction Mixture with 30% TBP in ISOPAR-M on the Lower Temperature Limit of Flame Propagation | 10.1134/S106636222006003X |
2020-06-01 | This study presents a 2-D analytical surface potential model is advanced by derived the expression from the 2-D Poisson’s equation of heterostructure double gate tunnel FET with channel-source junction-pocket doped. The dual benefits of heterostructure and channel-source junction -pocket doping are incorporated in a single device. In addition, to the surface potential, we calculated the electric field and then the expression is obtained by integrating the tunneling region. The analytical model adequate calculates the channel surface potential and predicts the electric field of a proposed structure. We also examine the necessity of the surface potential on the structure constraints by varying the gate bias, gate dielectric thickness, channel-source junction pocket doping concentration, length of pocket doping. To confirm analytical consequences, we have also simulated the proposed device using Silvaco T-CAD Simulator. Moreover, the drain current, output characteristics and, ON-current with different dielectric and, doping concentration of the proposed device has been considerably observed using a simulator. | A Two Dimensional Analytical Model of Heterostructure Double Gate with Pocket Doped Tunnel FET | 10.1007/s12633-019-00232-3 |
2020-06-01 | In drought prone areas, often farmers use less nitrogen, and thus the crop is subjected to combined stress (low N + osmotic stress). Since understanding the regulation of genes involved in nitrate signalling, uptake and assimilation under water-deficit (osmotic stress) is important for improving yield under the combined stress environments, this study analysed the regulation of genes coding for N responses under low N, osmotic stress (OS) and combined stress conditions in seedlings of a wheat. The results revealed that HD2967, a mega wheat variety, was more tolerant to short-term N starvation, OS and combined stress as compared with C306, a drought tolerant check. Interestingly, it was found that low N stress can also lead to accumulation of ABA in wheat seedlings. Real-time RT-qPCR analysis revealed that in addition to low N stress, OS also regulated expression of nitrate signalling genes ( TaCIPK8 , TaCIPK23 , TaNLP4 , TaSPL9 , TabHLH1 and TaNAC4 ), HATS gene TaNRT2.1 , LATS genes ( TaNRT6.5 and TaNPF7.1 ), nitrate and nitrite assimilation genes and ammonium assimilation genes at least in one tissue of one of the genotypes. Combined stress was found to have significant interaction in regulation genes for nitrate signalling, uptake and assimilation. TabZIP1 and TaPIMP1 TF were identified as new players in low N response in wheat. Thus, osmotic stress and combined stress modulates the genes for N responses, and genotypic variation exists for this in wheat. The common expression pattern of N response genes found under low N and OS may probably regulated, at least in part, by ABA-dependent pathway, as ABA accumulation was induced by both OS and low N stresses. Functional analysis of the osmotic stress regulated genes coding for N response will help enhance tolerance of wheat to combined stress conditions. | Regulation of expression of genes associated with nitrate response by osmotic stress and combined osmotic and nitrogen deficiency stress in bread wheat (Triticum aestivum L.) | 10.1007/s40502-020-00503-x |
2020-06-01 | Results of investigations of acoustic signals induced in a copper plate irradiated with a microsecond lowenergy high-current electron beam (LEHCEB) are presented. The characteristic acoustic signal waveforms, their amplitudes, phases, and frequencies are experimentally measured. It has been established that the acoustic signals induced by LEHCEB irradiation have groups of characteristic spectral components with fundamental frequencies of 6, 11, 22–24, 80, and 100–120 kHz whose amplitudes increased with charging voltage. It has been established that from the change of the 80 kHz harmonic with the charging voltage, the beginning of LEHCEB generation, its stable or unstable phase, and the beginning of target melting can be traced. It has been found that for a fixed charging voltage of each pulse in a series, the amplitude and phase-frequency structure of acoustic signals are almost the same. | Acoustic Signals Induced in a Copper Target under Irradiation by a Low-Energy High-Current Electron Beam | 10.1007/s11182-020-02031-5 |
2020-06-01 | An intensive analysis of far-infrared (far-IR), low-frequency Raman, and wide angle X-ray diffraction (WAXD) data has been performed by two-dimensional correlation spectroscopy (2D-COS) as a function of the blend ratio of poly(3- hydroxybutyrate)/poly(4-vinylphenol) (PHB/PVPh). Homospectral 2D-COS revealed that a weak band at 128 cm −1 in the far-IR spectra appeared more clearly in the 2D correlation spectra. Heterospectral 2D-COS (far-IR/low-frequency Raman and far-IR/WAXD) provided very important results that were hardly detected in the conventional 2D-COS. A far-IR peak at 130 cm −1 in the heterospectral 2D-COS had negative correlations with the peaks in the low-frequency Raman spectra at 81, 100, and 110 cm −1 and WAXD profile 8.78 and 11.01°. These results indicated that those peaks have different origins; the 130 cm −1 peak comes from the intermolecular C=O···H–O hydrogen bond between PHB and PVPh, while those for low-frequency Raman and WAXD peaks are the features of PHB crystalline structure. | A Study on Blend Ratio-dependent Far-IR and Low-frequency Raman Spectra and WAXD Patterns of Poly(3-hydroxybutyrate)/ poly(4-vinylphenol) Using Homospectral and Heterospectral Two-dimensional Correlation Spectroscopy | 10.2116/analsci.19P428 |
2020-06-01 | Expanding the use of a recently introduced low-cost particle monitor (DC1700 Dylos Air Quality Monitor) for sensing atmospheric PM 2.5 requires comparison with data obtained using a certified method for PM 2.5 based on appropriate atmospheric observations. Full-year measurements of atmospheric aerosols were taken in Nagoya, Japan during March 2017-March 2018 using the DC1700 to measure the particle number concentrations of >0.5 and >2.5 μm diameter particles and to measure the PM 2.5 mass concentration ( M dry, PM2.5 ) using an automated β attenuation mass monitor (PM712). The number-size distribution was measured using an optical particle counter (KC01D). The dried mass concentration of 0.5–2.5 μm particles ( M dry, 0.5–2.5 ) was estimated from the ambient relative humidity and the DC1700 number concentration. The values of M dry, 0.5–2.5 were invariably less than those of M dry, PM2.5 . The coefficient of determination and slope of M dry, 0.5–2.5 to M dry, PM2.5 for the year were, respectively, 0.68 and 0.40. Slope values changed seasonally from 0.24 in July and August 2017 to 0.55 in May and April 2017. Light absorbing particles, smaller-fine particles, and the estimation method of M dry, 0.5–2.5 were inferred as causes of the difference between M dry, 0.5–2.5 and M dry, PM2.5 . Especially, we estimated a large contribution (ca. 54% underestimation of M dry, 0.5–2.5 into M dry, PM2.5 ) of particles smaller than the minimum detection diameter of DC1700. The seasonal variation of M dry, 0.5–2.5 / M dry, PM2.5 was related to the volume fraction of particles smaller than 0.5 μm. Good correlation of M dry, 0.5–2.5 to M dry, PM2.5 suggests that data obtained using DC1700 with a correction factor are useful as a rough proxy of atmospheric PM 2.5 within a season. However, precise estimation of PM 2.5 from the DC1700 number concentrations should include appropriate corrections of the size distribution, not only hygroscopicity. | Estimating Mass Concentration Using a Low-cost Portable Particle Counter Based on Full-year Observations: Issues to Obtain Reliable Atmospheric PM2.5 Data | 10.5572/ajae.2020.14.2.155 |
2020-06-01 | Periodontal disease is a chronic progressive inflammatory process leading to damage of tooth-supporting tissues. This comparative study assessed the effect of PhotoBioModulation (PBM) versus conventional therapy, and investigated biomarkers involved in the healing process. The test group comprised twenty systemically-healthy non-smoking subjects with chronic periodontitis with the presence of two matched contro-lateral premolar sites (probing depth > 5 mm); twenty subjects without chronic periodontitis (CP) served as control group. Patients were treated at baseline, either with scaling and root planing (SRP group) or with a procedure entailing SRP supported by PBM (PBM group). The laser used was a diode laser operating at 645 nm wavelength, 10 J/cm2, and 0.5 W/cm2 with a 600 μm fiber optic. Crevicular fluid levels of bradykinin (BK), vascular endothelial growth factor (VEGF), and epidermal growth factor z (EGF) were determined at both sites. Crevicular fluid specimens from both groups were analyzed with the ELISA TEST. Clinical differences in analyzed outcomes were observed in favor of PBM treatment. Taking average values as 100%, the reduction in BK concentration was 47.68% with SRP and 68.43% with PBM on day 3; the VEGF concentration decreased by 35.73% with SRP and 48.59% with PBM on day 7; the EGF concentration increased by 55.58% with SRP and by 58.11% with PBM on day 21. Clinical parameters improved significantly in both groups (pooled mean values of probing depth decreased from 5.6 to 4.5 mm; gingival index from 1.92 to 1.1; and bleeding on probing from 49.67 to 23.23) but did not vary significantly between the PBM and the SRP group. The results confirmed that PBM have beneficial effects in the early phases of the healing process playing a role in modulation of BK, EGF, and VEGF in gingival crevicular fluid levels; both groups had significant clinical improvement over control but there was no significant difference between them, only a trend for PBM group. The overall results of the study suggest a potential benefit of PBM in conjunction with SRP in treating chronic periodontitis. | Evaluation of bradykinin, VEGF, and EGF biomarkers in gingival crevicular fluid and comparison of PhotoBioModulation with conventional techniques in periodontitis: a split-mouth randomized clinical trial | 10.1007/s10103-019-02919-w |
2020-06-01 | Due to high gas content, high geo-stress and complex geological conditions, gas disasters occur frequently in deep coal mining. The hard thick roof (HTR) greatly increases the difficulty of coalbed gas control besides causing dynamic disasters. In this paper, the effects of HTR on gas migration were numerically analyzed based on a multi-field coupling model. Results indicated that the hanging arch leads to remarkable stress concentration and induces a “cap-shaped” low-permeable zone above the gob, which greatly prevents gas from migrating upwards. Meanwhile, HTR hinders the subsidence movements of the upper rock strata, contributing to very few roof fractures and bed-separated fractures. Without the formation of roof-fractured zone, coalbed gas completely loses the possibility of upward concentration and will accumulate in the gob, forming a major safety hazard. To overcome these problems, borehole artificially guided pre-splitting (BAGP) technology was proposed. Three different pre-splitting boreholes were constructed as a group to generate artificial fractures in advance in HTR via deep-hole blasting, promoting the evolution of roof fractures. With the effects of mining stress, a fracture network is eventually formed in HTR, which provides a preferential passage for the upward flow of coalbed gas. Moreover, the controllable breaking of HTR was achieved and the roof strata could deform and subside regularly, forming an “O-shaped” roof-fractured zone above the gob which greatly improves the gas extraction efficiency of roof high-level boreholes. In addition, after BAGP, several extraction measures can be applied in the gob-side entry to drain the gas in different concentrated areas. In the field experiment, the roof periodic breaking length was reduced by half, and the average gas extraction rate was increased by 4 times to 67.7%. The synergetic controls of HTR and coalbed gas were effectively realized. This study provides valuable insight into gas control in other deep coal mines with similar geological conditions. | Study of Effects of Hard Thick Roof on Gas Migration and Field Experiment of Roof Artificially Guided Pre-splitting for Efficient Gas Control | 10.1007/s11053-019-09531-3 |
2020-06-01 | Aiming at the problem that some security factors in large scale construction projects are difficult to be discovered in time and easily cause accidents, a low-power long-distance data acquisition and transmission scheme using LoRa wireless sensor network is proposed. Firstly, the improved linear integer programming (IILP) model is used to deploy sensor nodes, which is used to collect security risk data. Then, an ARM processor with a high-performance Cortex-M3 architecture is used by the LoRa node to interconnect the LoRa module via the SPI bus for data communication. Finally, the LoRa node sends the data collected by the sensor to the LoRa gateway through the wireless signal, and the data is stored in the cloud database through the TCP/IP protocol. Experimental tests are carried out in actual subway construction projects. The temperature and humidity sensors, deep horizontal displacement sensors, supporting shaft force sensors and groundwater level sensors are installed on the nodes to monitor real-time safety risk factors in the construction process. It is found that under the premise of ensuring more than 90% of the data transmission success rate, the proposed communication distance can be as far as 700 m. Compared with several other schemes, the proposed scheme can show better performance in terms of throughput and network delay. The simulation results of sensor deployment show that the improved ILP model can improve the performance of sensor deployment and save hardware cost to a certain extent. In addition, the proposed scheme combines the advantages of LoRa technology with the characteristics of low maintenance cost and long service life, and has a good reference significance for the application of Internet of Things technology in large-scale construction projects. | Data Acquisition and Transmission Scheme for Large Projects Based on LoRa Internet of Things Using Improved Linear Integer Programming Model | 10.1007/s10776-019-00454-7 |
2020-06-01 | Skin graft is one of the most common techniques used in plastic surgery and repair. However, there are some complications that can lead to loss of the skin graft. Thus, several features have been studied with the aim of promoting the integration of skin grafts. Among these resources, the use of laser photobiomodulation (laser PBM) has been highlighted. The present study aimed to investigate the effects of laser PBM on the viability and integration of skin grafts in rats. Twenty male Wistar rats (± 250 g) were randomly assigned into two experimental groups with 10 animals each: control group, animals submitted to skin graft and simulation of laser PBM; laser PBM group, submitted to the skin graft and submitted to laser PBM at 660 nm, 40 mW, 60 s, 2.4 J. The animals were submitted to laser photobiomodulation immediately after the surgical procedure and each 24 h. Animal euthanasia occurred on the 7th day after surgery, 24 h after the last treatment session. The histopathological analysis revealed that the laser PBM showed better adhesion of the graft when compared to the control group. Likewise, the morphometric analysis of mast cells, blood vessels, and collagen showed a statistically significant increase in the animals irradiated with the laser PBM when compared to the control group. In addition, immunohistochemical analysis demonstrated that the laser PBM showed statistically higher immunoexpression of FGF when compared to the CG. However, IL-4 immunoexpression did not show statistical difference between the experimental groups. From the results obtained in the present study, it can be suggested that laser photobiomodulation was effective in promoting the integration and viability of total skin grafts in rats. | Effects of photobiomodulation therapy in the integration of skin graft in rats | 10.1007/s10103-019-02909-y |
2020-06-01 | The loosely coupled independent hardware of any kind under internet protocol refers to the Internet of Things (IoT). The IoT network has often framed by the composition of various standards, techniques, and services that are having diversified privacy & security prerequisites. Therefore, it has noted that paradigm IoT has similar problems of security as cloud services, the internet, and “mobile communication networks”. Nevertheless, the outdated countermeasures of security, & implementation of privacy cannot be applied directly to the technologies of IoT because of confined IoT elements computing power, the maximum amount of interrelated devices & data sharing among users & objects. The proposals of IDS for the IoT will be placed to be distributed or central system or in the combination of bi-phase systems. The traditional intrusion detection strategies detect intrusion either by signature, anomalies, or a combination of any of these. Due to the limited resources of the devices placed in IoT networks, the intrusion detection strategies should perform the intrusion defense under the constrained resources of the corresponding devices. Regarding this argument, a novel specification measure that allows each of the devices falls in an IoT network to defend the intrusion at a corresponding device level. The method explored in this manuscript is a specification approach that determines Specification Heuristics to assess the scope of intrusion in IoT network requests. | SH-IDS: Specification Heuristics Based Intrusion Detection System for IoT Networks | 10.1007/s11277-020-07137-0 |
2020-06-01 | The goal was to investigate the time dynamic nature of the secreted protein profiles at 15–240 kDa, expressed by MDA-MB-231 breast cancer cells, exposed to 240 ± 12 mGy dose. After 2 h, a variety of proteins in the supernatant reduced their concentration up to 10–12 h, as an early event. After 24 h, up- and down-regulations of the secretions of several factors were postulated, indicating significant radio-induced changes. At a late event, in 48–96 h, the findings pointed out to distinct radio-induced modulations characterizing early and late profiles. Such findings suggest dynamic secretome behavior, possibly related to distinct MDA-MB-231 phenotypes. | Dynamic modulations of the MDA-MB-231 secretions at low dose radiation | 10.1007/s10967-020-07139-z |
2020-06-01 | Purpose Low birth weight (LBW) infants have a less diverse gut microbiota, enriched in potential pathogens, which places them at high risk of systemic inflammation diseases. This study aimed to identify the differences in gut bacterial community structure between LBW infants who received probiotics and LBW infants who did not receive probiotics. Methods Forty-one infants were allocated to the non-probiotic group (N group) and 56 infants to the probiotic group (P group), according to whether the formula they received contained a probiotic Bifidobacterium lactis . Gut bacterial composition was identified with sequencing of the 16S rRNA gene in fecal samples collected at 14 days after birth. Results There was no significant difference between the alpha diversity of the two groups, while the beta diversity was significantly different ( p < 0.05). Our results showed that Bifidobacterium and Lactobacillus (both p < 0.05) were enriched in the P group, while Veillonella , Dolosigranulum and Clostridium sensu stricto 1 (all p < 0.05) were enriched in the N group. Predicted metagenome function analysis revealed enhancement of fatty acids, peroxisome, starch, alanine, tyrosine and peroxisome pathways in the P group, and enhancement of plant pathogen, Salmonella and Helicobacter pylori infection pathways in the N group. Conclusions Probiotic supplement in formula may affect the composition, stability and function of LBW infants’ gut microbiota. LBW infants who receive probiotic intervention may benefit from gut microbiota that contains more beneficial bacteria. | Effects of a formula with a probiotic Bifidobacterium lactis Supplement on the gut microbiota of low birth weight infants | 10.1007/s00394-019-02006-4 |
2020-06-01 | This study aimed to histologically and radiographically evaluate the effectiveness of low-intensity laser irradiation of different wavelengths (660 or 808 nm) as an adjunct to scaling and root planing in the treatment of experimental periodontitis in rats. Periodontitis was induced by placing a ligature around the mandibular first molar of the rats. In total, 40 Wistar rats were randomly divided into five groups ( n = 8 each): control (CG), periodontal disease (PD), scaling and root planing (SRP), SRP + 660 nm laser (GL660) and SRP + 808 nm laser (GL808). Groups with laser use received radiation at 6 points in the first molar. The animals were euthanized at baseline and at 7 and 14 days after the interventions. Mandibles were surgically removed for histomorphometric and radiographic assessment of periodontal tissues. The GL660 group showed lesser bone loss than the PD group ( P < 0.05) and greater alveolar bone margin after 14 days, indicating a better long-term treatment response ( P < 0.05). These findings suggest that SRP with the 660 nm laser as an adjunct results in more favorable radiographic and histological responses than the 808 nm laser. | Effect of photobiomodulation therapy as an adjunct to scaling and root planing in a rat model of ligature-induced periodontitis: a histological and radiographic study | 10.1007/s10103-020-02952-0 |
2020-06-01 | Abstract The variation of low-energy slow secondary electron emission from the surface of relief structures (bumps) during their prolonged scanning in a low-voltage scanning electron microscope is estimated. The variation nature depends on the bump region profile, which is especially complex near relief structure angles. As a result, corresponding curve portions of the bump video signal, which results in an increase or even a decrease in geometrical sizes of these portions. The emission variation is explained by local charge induction in the natural oxide layer on the silicon surface. The portion size also changes due to contamination film bump deposition on the surface. Presumably, its deposition depends on charges induced on the bump surface and, hence, is poorly reproducible. The case of the absence of contamination broadening of a bump due to its prolonged scanning is fixed. | Surface State Variation during Scanning in a Low-Voltage SEM and Its Effect on of Relief Structure Sizes | 10.1134/S106378342006013X |
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