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Characteristics of the crack tip field in high-speed railway tunnel linings under train-induced aerodynamic shockwaves

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Underground Space 2024年第5期18卷 199-217页

作者： Yi-Kang Liu Yu-Ling Wang e deng Yi-Qing Ni Wei-Chao Yang Wai-Kei Ao School of Civil engineering Central South UniversityChangsha 410075China National Rail Transit electrification and Automation engineering Technology Research Center(Hong Kong Branch) The Hong Kong Polytechnic UniversityHong Kong 999077China department of Civil and environmental engineering The Hong Kong Polytechnic UniversityHong Kong 999077China The Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518057China National engineering Research Center of High-speed Railway Construction Technology Changsha 410075China

High-speed railway tunnels in various countries have continuously reported accidents of vault falling concrete *** the concrete block falling occurs,serious consequences follow,and traffic safety may be *** aerodynamic shockwave evolves from the initial compression wave may be an important inducement causing the tunnel lining cracks to grow and form falling concrete blocks.A joint calculation framework is established based on ANSYS Fluent,ABAQUS,and FRANC3d for calculating the crack tip field under the aerodynamic *** intensification effect of aerodynamic shockwaves in the crack is revealed,and the evolution characteristics of the crack tip field and the influence factors of stress intensity factor(SIF)are *** show that(1)the aerodynamic shockwave intensifies after entering the crack,resulting in more significant pressure in the crack than the input *** maximum pressure of the inclined and longitudinal cracks is higher than the corresponding values of the circumferential crack,respectively.(2)The maximum SIF of the circumferential,inclined,and longitudinal crack appears at 0.5,0.68,and 0.78 times the crack front *** maximum SIF of the circumferential crack is higher than that of the inclined and longitudinal *** possibility of crack growth of the circumferential crack is the highest under aerodynamic shockwaves.(3)The influence of train speed on the SIF of the circumferential crack is more than 40%.When the train speed,crack depth,and crack length change,the change of pressure in the crack is the direct cause of the change of SIF.

关键词： Falling concrete blocks Tunnel lining cracks Aerodynamic shockwave Intensification effect Crack tip field Stress intensity factor

3d Printed Polyimide/Silica Composite Aerogels for Customizable Thermal Insulation from-50℃ to 1300℃

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Chinese Journal of Polymer Science 2024年第7期42卷 936-945,I0007页

作者： dingyi Yu Tiantian Xue Zhuocheng Ma Zaiyin Hu Lijuan Long Yue-e Miao Wei Fan Tianxi Liu State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai201620China Key Laboratory of Synthetic and Biological Colloids Ministry of EducationSchool of Chemical and Material EngineeringJiangnan UniversityWuxi214122China Guizhou Aerospace Wujiang electro-Mechanical equipment Co. Ltd.Zunyi563000China School of Materials and Architectural engineering Guizhou Normal UniversityGuiyang550025China

Aerogels are widely used as thermal insulation materials because of their high porosity and low bulk ***,the insulation performance of aerogels is limited to a narrow temperature ***,the preparation of aerogel materials with precisely controlled and complex architectures is still ***,we report 3d printed polyimide/silica aerogel particle(PI/SAP)composite aerogels for thermal insulation in a wide range of temperature with customized *** printability and shape fidelity of 3d printed composite aerogels is improved by adding hydrophilic SAP as a rheology *** resulting PI/SAP composite aerogel exhibits excellent flame-retardant properties and thermal insulation from-50℃ to 1300℃.Moreover,the PI/SAP composite aerogel with customized shape can be applied for battery insulation at subzero temperatures,promising to be used as customizable and stable insulating materials in a variety of complex and extreme applications.

关键词： 3d printing Polyimide Aerogel Silica Thermal insulation

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Continuous Lithium-Ion extraction From Seawater and Mine Water With a Fuel Cell System and Ceramic Membranes

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energy & environmental Materials 2024年第6期7卷 254-261页

作者： Cansu Kök Lei Wang Jean Gustavo A.Ruthes Antje Quade Matthew e.Suss Volker Presser INM–Leibniz Institute for New Materials Campus D2266123Saarbr¨uckenGermany department of Materials Science&engineering Saarland UniversityCampus D2266123Saarbr¨uckenGermany Leibniz Institute for Plasma Science and Technology Felix-Hausdorff-Straße 217489GreifswaldGermany Faculty of Mechanical engineering Technion–Israel Institute of TechnologyHaifa3200003Israel Wolfson department of Chemical engineering Technion–Israel Institute of TechnologyHaifa3200003Israel Grand Technion energy Program Technion–Israel Institute of TechnologyHaifa3200003Israel Saarene–Saarland Center for energy Materials and Sustainability Campus C4266123Saarbr¨uckenGermany

The demand for electronic devices that utilize lithium is steadily increasing in this rapidly advancing technological *** high-purity lithium in an environmentally friendly way is challenging by using commercialized ***,we propose the first fuel cell system for continuous lithium-ion extraction using a lithium superionic conductor membrane and advanced *** fuel cell system for extracting lithium-ion has demonstrated a twofold increase in the selectivity of Li^(+)/Na^(+)while producing *** data show that the fuel cell with a titania-coated electrode achieves 95%lithium-ion purity while generating 10.23 Wh of energy per gram of *** investigation revealed that using atomic layer deposition improved the electrode's uniformity,stability,and electrocatalytic *** 2000 cycles determined by cyclic voltammetry,the electrode preserved its stability.

关键词： atomic layer deposition cation selectivity electrochemical lithium-ion extraction fuel cell

Lighting up aggregate emission of perylene diimide by leveraging polymerization-mediated through-space charge transfer and π-π stacking

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Science China Chemistry 2024年

作者： Suiying Ye désirée Füglistaller Tian Tian Anjay Manian Sudhir Kumar Celine Nardo Andrew J.Christofferson Salvy P.Russo Chih-Jen Shih Jean-Christophe Leroux Yinyin Bao Institute of Pharmaceutical Sciences Department of Chemistry and Applied Biosciences ETH Zurich Vladimir-Prelog-Weg 3 Institute for Chemical and Bioengineering Department of Chemistry and Applied Biosciences ETH Zurich Vladimir-Prelog-Weg 1-5 ARC Centre of excellence in exciton Science School of Science RMIT University School of Science STEM College RMIT University

The molecular engineering of fluorescent organic/polymeric materials, specifically those emitting in the deep red to near-infrared spectrum, is vital for advancements in optoelectronics and biomedicine. Perylene diimide(PdI), a well-known fluorescent scaffold, offers high thermal and photophysical stability but suffers from fluorescence quenching in solid or aggregate states due to intense π-π interactions. To mitigate this, simple and versatile methods for strong PdI aggregate emission without extensive synthetic demands are highly desirable but still lacking. Here, we report a straightforward strategy to enhance the solid-state emission of PdI by introducing certain degree of through-space charge transfer(TSCT) via controlled radical polymerization,which can efficiently distort the typical face-to-face PdI stacking, enabling greatly enhanced deep red emission. This is achieved by growing electron-donating star-shape styrenic(co)polymers from a multidirectional electron-accepting PdI initiator. The incorporation of polycyclic aromatic monomers further shifted the emission into the near-infrared region, albeit with a reduced intensity. Overall, the emission of the PdI-based TSCT polymers can be systematically manipulated by leveraging the balance between PdI stacking and the TSCT degree, as confirmed by both experimental study and theoretical calculations. Our approach circumvents complex synthetic procedures, offering highly emissive materials with large Stokes shifts and showing broad potential for optoelectronic technology.

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Socioenvironmental drivers of Farmers’ Perceptions of Climate Change Risk in Agroforestry Parklands of West Atacora in Benin (West Africa)

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Open Journal of ecology 2024年第1期14卷 54-65页

作者： Amos Baninwain Nambima Thierry dèhouégnon Houehanou Narcisse Yehouenou dowo Michée Adjacou Abdul Sodick Alassiri Gérard Gouwakinnou Laboratory of ecology Botany and Plant Biology (LEB) Faculty of Agronomy (FA) University of Parakou (UP) Parakou Republic of Benin

Throughout the world, climate change is threatening the human population. In West Africa, smallholder farmers in indigenous agricultural societies typically hold considerable knowledge. Therefore, this study was conducted in West Atacora of Benin Republic to assess the drivers of farmers’ perceptions of climate change risk. We used a random sampling technique to select 360 households’ heads who were interviewed regarding different climate change risks perception. Binomial logistic regression was used to assess the drivers of farmers’ perceptions of climate change risks. The results showed that the farmers in drier areas had a higher perception of the global risk of climate change than those in humid areas. The same trend was observed for the seven different individual’s climate change risk investigated. The study identified also membership of farm organizations as main sociodemographic characteristic that explains farmers’ perception of climate change risk perception. These findings are helpful tools to sensitize the local people on climate change risk and cope with the risk in agricultural lands.

关键词： Climate Change Risk Local ecological Knowledge Socio-demographic Characteristics Benin West Africa

Influence of previous plane of nutrition on molecular mechanisms regulating the expression of urea and water metabolism related genes in the rumen and kidney of finishing crossbred Angus steers

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Animal Nutrition 2024年第2期17卷 232-243页

作者： Aghata e.Moreira da Silva Arturo Macias Franco Bradley S.Ferguson Mozart A.Fonseca College of Agriculture Biotechnology&Natural Resources University of Nevada department of Animal and Range Sciences Clayton Livestock Research Center New Mexico State University

This study aimed to understand how molecular mechanisms controlling water and urea metabolism at the finishing phase can be affected by previous plane of nutrition of crossbred Angus beef steers. Twentyfour(n = 24) animals were randomly distributed into either a moderate(MP) or high plane of nutrition during the background phase for 85 d. Animals were then blocked by their previous plane and were moved onto a 105-d finishing phase in a 2 × 2 factorial arrangement. The forage-finished group received only high-quality alfalfa hay, whereas the grain-fed group received a high grain diet(80% whole corn and20% alfalfa hay). By the end of the finishing phase, animals were harvested and tissue samples from the rumen and kidney were collected. Changes in gene expression of aquaporins(AQP)-2,-3,-4,-7, ATP1A1,ATP1B1, SGK1, CLIC1(kidney and rumen), UT-A1(kidney only) and UT-B(rumen only), were assayed via real-time q PCR; 18S r RNA was used as an endogenous control. One-way ANOVA followed by Tukey's post hoc analysis was conducted. When animals were from MP, forage-finishing increased the relative abundance of AQP3(P ≤ 0.05), AQP7(P ≤ 0.05), ATP1B1(P ≤ 0.05), and SGK1(P ≤ 0.05) in the kidney when compared to grain-fed animals. In the rumen, for the MP group, AQP7 was differentially expressed in both treatments at the finishing phase(P ≤ 0.01), with forage-finished steers having the highest expression of AQP7. For the MP group, UT-B had a tendency of presenting a higher expression on grainfed animals(P = 0.075). Overall, these results suggest that previous plane can impact expression of genes associated with water and urea metabolism during the finishing phase, namely AQP3, AQP7, ATP1B1, and SGK1 in the kidney, and AQP7 and UT-B in the rumen. The greatest impact observed on gene expression changes of investigated genes at the finishing phase was reflective of animals backgrounded on the moderate previous plane.

关键词： Gene expression Aquaporin Sodium channel Urea transporter

Interactions between maternal parity and feed additives drive the composition of pig gut microbiomes in the post‑weaning period

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Journal of Animal Science and Biotechnology 2024年第3期15卷 1241-1257页

作者： Kayla Law eduardo Rosa Medina Garcia Chad Hastad deborah Murray Pedro e.Urriola Andres Gomez department of Animal Science University of Minnesota1364 Eckles AvenueSaint PaulMN 55108USA New Fashion Pork 164 Industrial ParkwayJacksonMN 56143USA

Background Nursery pigs undergo stressors in the post-weaning period that result in production and welfare *** challenges disproportionately impact the offspring of primiparous sows compared to those of mul-tiparous *** is known regarding potential interactions between parity and feed additives in the post-weaning period and their effects on nursery pig ***,the objective of this study was to investigate the effects of maternal parity on sow and offspring microbiomes and the influence of sow parity on pig fecal microbi-ome and performance in response to a prebiotic *** weaning,piglets were allotted into three treat-ment groups:a standard nursery diet including pharmacological doses of Zn and Cu(Con),a group fed a commercial prebiotic only(Preb)based on an Aspergillus oryzae fermentation extract,and a group fed the same prebiotic plus Zn and Cu(Preb+ZnCu).Results Although there were no differences in vaginal microbiome composition between primiparous and mul-tiparous sows,fecal microbiome composition was different(R^(2)=0.02,P=0.03).The fecal microbiomes of primiparous offspring displayed significantly higher bacterial diversity compared to multiparous offspring at d 0 and d 21 post-weaning(Pdifferences in community composition observed at d 21(R^(2)=0.03,P=0.04).When analyzing the effects of maternal parity within each treatment,only the Preb diet triggered significant microbiome distinc-tions between primiparous and multiparous offspring(d 21:R^(2)=0.13,P=0.01;d 42:R^(2)=0.19,P=0.001).Composi-tional differences in pig fecal microbiomes between treatments were observed only at d 21(R^(2)=0.12,P=0.001).Pigs in the Con group gained significantly more weight throughout the nursery period when compared to those in the Preb+ZnCu *** Nursery pig gut microbiome composition was influenced by supplementation with an Aspergillus oryzae fermentation extract,with varying effects on performance

关键词： Aspergillus prebiotic Copper Feed additives Maternal Nursery pig microbiome Parity Swine microbiome Trace minerals Zinc

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Female Contraception: Comparative Study of Biometrics and Vascularization of the Uterus at Sylvanus Olympio University Hospital (Togo)

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Open Journal of Obstetrics and Gynecology 2024年第1期14卷 162-174页

作者： dédé Régine diane Ajavon Metoukam Andrée Josiane douaguibe Baguilane Ketevi Améyo Ayoko Logbo Akey Kossi edem Kambote Yendoube M’bortche Bingo Amadou Abdoulatif Aboubakari Abdoul Samadou Faculty of Health Sciences University of Kara Kara Togo Faculty of Health Sciences University of Lomé Lomé Togo Service de gynécologie obstétrique du CHU Sylvanus Olympio Lomé Togo

Female contraception uses both hormonal and non-hormonal methods. The aim of the study is to determine the impact of female contraception on uterine vascularisation and the endometrium. Method: It was a descriptive comparative study with an analytical aim. It took place at the University Clinic of Obstetrics Gynaecology and the Radiology and Medical imaging department of Sylvanus Olympio University Hospital in Lomé over a two-month period from May 15, 2023 to July 15, 2023. Group 1 included women using a modern contraceptive method and group 2 women not using a modern contraceptive method. epidata 3.1 and R 4.0.4 software were used to process the data. Results: each group included 50 women. There were no significant differences in uterine and endometrial biometrics. All women on contraception had their zone 1 vascularized, without vascularisation of zone 2, without significant difference with women without contraception The pulsatility index was greater than 3 in 51% (n = 51) of women, including 62.7% (n = 32) of women without contraception and 37.3% (n = 19) of women on contraception, with a statistically significant difference (p = 0.009). Conclusion: Contraceptive methods do not influence the biometry of the uterus. However, uterine artery doppler indices can predict abnormal uterine bleeding.

关键词： Contraception endometrium Uterine Artery doppler

Adding Value to Crop Production Systems by Integrating Forage Cover Crop Grazing

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American Journal of Plant Sciences 2024年第3期15卷 180-192页

作者： Robert B. Mitchell daren d. Redfearn Kenneth P. Vogel Terry J. Klopfenstein Galen erickson P. Stephen Baenziger Bruce e. Anderson Mary e. drewnoski Jay Parsons Steven d. Masterson Marty R. Schmer Virginia L. Jin USdA-ARS Wheat Sorghum and Forage Research Unit University of Nebraska-Lincoln Lincoln NE USA department of Agronomy and Horticulture University of Nebraska-Lincoln Lincoln NE USA department of Animal Science University of Nebraska-Lincoln Lincoln NE USA department of Agricultural economics University of Nebraska-Lincoln Lincoln NE USA USdA-ARS Agroecosystem Management Research Unit University of Nebraska-Lincoln Lincoln NE USA

In addition to their value as cereal grains, wheat (Triticum aestivum L.) and triticale (× Triticosecale Wittmack) are important cool-season annual forages and cover crops. Yearling steer (Bos taurus) performance was compared in the spring following autumn establishment as for age cover crops after soybean [Glycine max (L.) Merr.] grain harvest. Replicated pastures (0.4 ha) were no-till seeded in three consecutive years into soybean stubble in autumn, fertilized, and grazed the following spring near Ithaca, Ne, USA. each pasture (n = 3) was continuously stocked in spring with four yearling steers (380 ± 38 kg) for 17, 32, and 28 d in 2005, 2006, and 2007, respectively. In 2005, average daily gain (AdG) for steers grazing triticale exceeded the AdG for wheat by 0.31 kghd-1d-1. In 2006, wheat AdG exceeded that for triticale by 0.12 kghd-1d-1. In 2007, steers grazing wheat lost weight, while steers grazing triticale gained 0.20 kghd-1d-1. Based on the 3-year average animal gains valued at $1.32 kg-1, mean net return ($ ha-1 yr-1) was $62.15 for triticale and $22.55 for wheat. Since these grazed cover crops provide ecosystem services in addition to forage, grazing could be viewed as a mechanism for recovering costs and adds additional value to the system. Based on this 3-year grazing trial, triticale was superior to wheat and likely will provide the most stable beef yearling performance across years with variable weather for the western Cornbelt USA.

关键词： Cover crops Soybean Triticale Wheat