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Applying robust design to study the effects of stratigraphic characteristics on brittle failure and bump potential in a coal mine

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International Journal of Mining Science and Technology 2018年第1期28卷 137-144页

作者： Bo-Hyun Kim mark K.Larson Heather e.Lawson Spokane Mining Research Division NIOSH/CDC

Bumps and other types of dynamic failure have been a persistent, worldwide problem in the underground coal mining industry, spanning *** example, in just five states in the *** 1983 to 2014,there were 388 reportable *** significant advances in mine design tools and mining practices,these events continue to *** conditions have been associated with bump potential, such as the presence of stiff units in the local *** effect of a stiff sandstone unit on the potential for coal bumps depends on the location of the stiff unit in the stratigraphic column, the relative stiffness and strength of other structural members, and stress concentrations caused by *** study describes the results of a robust design to consider the impact of different lithologic risk factors impacting dynamic failure *** the inherent variability of stratigraphic characteristics in sedimentary formations,such as thickness, engineering material properties, and location, is significant and the number of influential parameters in determining a parametric study is large, it is impractical to consider every simulation case by varying each parameter ***, to save time and honor the statistical distributions of the parameters, it is necessary to develop a robust design to collect sufficient sample data and develop a statistical analysis method to draw accurate conclusions from the collected *** this study,orthogonal arrays, which were developed using the robust design, are used to define the combination of the(a) thickness of a stiff sandstone inserted on the top and bottom of a coal seam in a massive shale mine roof and floor,(b) location of the stiff sandstone inserted on the top and bottom of the coal seam,and(c) material properties of the stiff sandstone and contacts as interfaces using the 3-dimensional numerical model, *** completion of the numerical experiments, statistical and multivariate analysis are performed using

关键词： Bumps Robust design FLAC3D Plastic dissipated energy Multiple regression

effects of overburden characteristics on dynamic failure in underground coal mining

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International Journal of Mining Science and Technology 2017年第1期27卷 121-129页

作者： Lawson Heather e. Tesarik Douglas Larson mark K Abraham Habte NIOSH Office of Mine Safety and Health ResearchGround Control BranchSpokane WA 99207USA

Dynamic failures, or ‘‘bumps", remain an imperative safety concern in underground coal mining, despite significant advancements in engineering controls. The presence of spatially discrete, stiff roof units are one feature that has been linked to these events. However, an empirical stratigraphic review indicates that no significant difference exists in the relative commonality of discrete units between bumping and non-bumping deposits. Instead an apparent relationship exists between reportable bumping and the overall stiffness of the host rock. However, this initial study is too simplistic to be conclusive; to weight the relative impact of changes in a single variable, such as the thickness or location of sandstone members, it must be examined in isolation—i.e., in a setting where all other variables are held *** modelling provides this setting, and the effects of variability in a stiff discrete member in a hypothetical longwall mining scenario are investigated within the context of three stratigraphic ‘‘types",Compliant, Intermediate and Stiff. A modelling experiment examines changes in rupture potential in stiff roof units for each stratigraphic type as discrete unit thickness and location are manipulated through a range of values. Results suggest that the stiff-to-compliant ratio of the host rock has an impact on the relative stress-inducing effects of discrete stiff members. In other words, it is necessary to consider both the thickness and the distance to the seam, within the context of the host rock, to accurately anticipate areas of elevated rupture-induced hazard; acknowledging the presence of a discrete unit within the overburden in general terms is an insufficient indicator of risk. This finding helps to refine our understanding of the role of individual stiff, strong roof members in bumping phenomena, and suggests that a holistic view of overburden lithology and site-specific numerical modelling may be necessary to improve miner safety.

关键词： Dynamic failure Coal mining Bumps Bounces

Laser directed energy deposited, ultrafine-grained functional titanium-copper alloys tailored for marine environments: Antibacterial and anti-microbial corrosion studies

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Journal of Materials Science & Technology 2023年第35期166卷 21-33页

作者： Jiaqi Li Duyao Zhang Xiaobo Chen Dake Xu Dong Qiu Fuhui Wang mark easton Shenyang National Laboratory for Materials Science Northeastern UniversityShenyang 110819China Key Laboratory for Anisotropy and Texture of Materials(Ministry of education) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China School of engineering Centre for Additive ManufacturingRMIT UniversityMelbourneVIC 3000Australia

The microorganism-rich nature of the ocean imposes great challenges to the structural integrity of met-als over their service lifespan,including titanium(Ti)alloys,which are usually prone to microbiologically influenced corrosion(MIC).So,multifunctional anti-MIC Ti alloys need to be developed and *** paper investigates the effect of copper(Cu)concentration on the MIC resistance of a series of additively manufactured,ultrafine-grained Ti-x Cu(x=3.5,6.5 and 8.5 in wt.%)*** dependence of the cor-rosion resistance and MIC resistance on the Cu concentration of Ti-Cu alloy is interpreted considering all conceivable *** mechanisms for excellent corrosion resistance of Ti-Cu alloy in seawater are attributed to the strong passive film and small surface potential difference between ***-tural characterization reveals that uniformly distributed,nanosized Ti_(2) Cu phase led to increased reactive oxygen species in the bacterial membrane,which is the root reason for the superb anti-bacterial property(99.2%)for *** to pure Ti and Ti-6Al-4V,Ti-8.5Cu alloy features both high strength(yield stress>1000 MPa)and the best MIC resistance(97.5%).The combination of such balanced properties enables this functional 3D printed Ti-Cu alloy to become an ideal material for load-bearing applications in the marine environment.

关键词： Multifunctional titanium alloys Additive manufacturing Ultrafine grains Microbiologically influenced corrosion resistance Mechanical property Antibacterial property

Multiple endocrine factors regulate nutrient mobilization and storage in Aedes aegypti during a gonadotrophic cycle

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Insect Science 2023年第2期30卷 425-442页

作者： Xiaoyi Dou Kangkang Chen mark R.Brown Michael R.Strand Department of entomology University of GeorgiaAthensGeorgia30602United States Department of Plant Protection College of Horticulture and Plant ProtectionYangzhou UniversityYangzhouJiangsu ProvinceChina

Anautogenous mosquitoes must blood feed on a vertebrate host to produce *** gonadotrophic cycle is subdivided into a sugar-feeding previtellogenic phase that produces primary follicles and a blood meal-activated vitellogenic phase in which large numbers of eggs synchronously mature and are *** endocrine factors including juvenile hormone(JH),insulin-like peptides(ILPs),ovary ecdysteroidogenic hormone(OeH),and 20-hydroxyecdysone(20e)coordinate each gonadotrophic *** formation also requires nutrients from feeding that are stored in the fat *** of egg formation is best understood in Aedes aegypti but the role different endocrine factors play in regulating nutrient mobilization and storage remains *** this study,we report that adult female *** maintained triacylglycerol(TAG)stores during the previtellogenic phase of the first gonadotrophic cycle while glycogen stores *** contrast,TAG and glycogen stores were rapidly mobilized during the vitellogenic phase and then *** genes encoding enzymes with functions in TAG and glycogen metabolism were differentially expressed in the fat body,which suggested regulation was mediated in part at the transcriptional *** of function assays indicated that stored nutrients were primarily mobilized by adipokinetic hormone(AKH)while juvenoids and OeH regulated ***3 further showed evidence of negatively regulating certain lipolytic *** of function assays indicated AKH depends on the AKH receptor(AKHR)for ***,our results indicate that the opposing activities of different hormones regulate nutrient stores during a gonadotrophic cycle in ***.

关键词： adipokinetic hormone ecdysone endocrine glycogen insulin-like peptide juvenile hormone mosquito nutrient ovary ecdysteroidogenic hormone triacylglycerol

Short-term inhalation exposure evaluations of airborne antibiotic resistance genes in environments

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Journal of environmental Sciences 2022年第12期34卷 62-71页

作者： Zhenchao Zhou Xinyi Shuai Zejun Lin Lingxuan Meng Xiaoliang Ba mark AHolmes Hong Chen Institute of environmental Technology College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China Department of Veterinary Medicine University of CambridgeCambridge CB39DAUK

Antibiotic resistance is a sword of Damocles that hangs over *** regards to airborne antibiotic resistance genes(AARGs),critical knowledge gaps still exist in the identification of hotspots and quantification of exposure levels in different ***,we have studied the profiles of AARGs,mobile genetic elements(MGes)and bacterial communities in various atmospheric environments by high throughput q PCR and 16S r RNA gene *** propose a new AARGs exposure dose calculation that uses short-term inhalation(STI).Swine farms and hospitals were high-risk areas where AARGs standardised abundance was more abundant than suburbs and urban ***,resistance gene abundance in swine farm worker sputum was higher than that in healthy individuals in other *** correlation between AARGs with MGes and bacteria was strong in suburbs but weak in livestock farms and *** exposure analysis revealed that occupational intake of AARGs(via PM10)in swine farms and hospitals were 110 and 29 times higher than in suburbs,were 1.5×10^(4),5.6×10^(4)and 5.1×10^(2)copies,i.e.,61.9%,75.1%and 10.7%of the overall daily inhalation intake,*** study comprehensively compares environmental differences in AARGs to identify high-risk areas,and forwardly proposes the STI exposure dose of AARGs to guide risk assessment.

关键词： Airborne Antibiotic resistance genes(ARGs) Short-term inhalation Risk assessment

Rapid range expansion predicted for the Common Grackle(Quiscalus quiscula)in the near future under climate change scenarios

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Avian Research 2021年第4期12卷 569-575页

作者： Peter Capainolo Utku Perktaş mark DeFellowes Division of Vertebrate Zoology-Department of Ornithology American Museum of Natural HistoryCentral Park West@79th StreetNew YorkNY 10024-5192USA People and Wildlife Research Group School of Biological SciencesUniversity of ReadingWhiteknightsReading RG66ASUK Depart-ment of Biology(Zoology Section Biogeography Research Laboratory)Faculty of ScienceHacettepe UniversityBeytepe06800 AnkaraTurkey

Background:Climate change due to anthropogenic global warming is the most important factor that will affect future range distribution of species and will shape future biogeographic *** much effort has been expended in understanding how climate change will affect rare and declining species we have less of an understanding of the likely consequences for some abundant *** Common Grackle(Quiscalus quiscula;Linnaeus 1758),though declining in portions of its range,is a widespread blackbird(Icteridae)species in North America east of the Rocky *** study examined how climate change might affect the future range distribution of Common ***:We used the R package Wallace and six general climate models(ACCeSS1-0,BCC-CSM1-1,CeSM1-CAM5-1-FV2,CNRM-CM5,MIROC-eSM,and MPI-eSM-LR)available for the future(2070)to identify climatically suitable areas,with an ecological niche modelling approach that includes the use of environmental ***:Future projections suggested a significant expansion from the current range into northern parts of North America and Alaska,even under more optimistic climate change ***,there is evidence of possible future colonization of islands in the Caribbean as well as coastal regions in eastern Central *** most important bioclimatic variables for model predictions were Annual Mean Temperature,Temperature Seasonality,Mean Temperature of Wettest Quarter and Annual ***:The results suggest that the Common Grackle could continue to expand its range in North America over the next 50 *** research is important in helping us understand how climate change will affect future range patterns of widespread,common bird species.

关键词： Annual mean temperature Climate change Common Grackle ecological niche modelling Range shift Seasonality

Long-term agricultural activity affects anthropogenic soil on the Chinese Loess Plateau

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Journal of Arid Land 2017年第5期9卷 678-687页

作者： LI Xiaoyun WANG Yiquan mark e ReYNOLDS LI Xiaoping LU Xinwei School of Geography and Tourism Shaanxi Normal University Xi'an 710119 China SNNU-JSU Joint Research Center for Nano-environment Science and Health Xi'an 710119 China College of Resources and environment Northwest A&F University Yangling 712100 China Stockbridge School of Agriculture University of Massachusetts Massachusetts 01003 USA

Anthropogenic activities largely influence the soil quality of agricultural fields and the composition of soil. Samples of typical anthropogenic Loutu soil in the Guanzhong area of the Loess Plateau, Shaanxi Province, China were collected and measured for soil compaction, bulk density, total organic carbon（TOC）, active organic carbon（AOC）, and soil enzyme activities to investigate spatial variations in soil quality. The results indicate that soil compaction and bulk density increased with increasing distance from the farm village, whereas soil TOC, AOC, and soil enzyme activities firstly increased and subsequently decreased with increasing distance from the farm village. All of the tested parameters presented clear concentric distribution. Vertically, soil compaction and bulk density in the topsoil were lower than those in the subsoil, but all other tested parameters in the topsoil were significantly higher than those in the subsoil. In addition, there was a significant positive correlation between organic carbon content and enzyme activities, confirming that the spatial distribution of Loutu soil characteristics has been affected by long-term anthropogenic activities to some extent. The results of this study imply that the use of farmyard manure and appropriate deep plowing are important and effective ways to maintain and improve soil quality.

关键词： anthropogenic soil spatial variation organic carbon enzyme activity soil quality

Alternatives for large-scale production of cultured beef: A review

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Journal of Integrative Agriculture 2015年第2期14卷 208-216页

作者： Matilda S M Moritz Sanne e L Verbruggen mark J Post Department of Physiology Maastricht UniversityMaastricht 6229 ER The Netherlands Department of Physics Chemistry and Biology Linkping UniversityLinkping SE-581 83 Sweden

Cultured beef is a method where stem cells from skeletal muscle of cows are cultured in vitro to gain edible muscle tissue. For large-scale production of cultured beef, the culture technique needs to become more efficient than today＇s 2-dimensional（2D） standard technique that was used to make the first cultured hamburger. Options for efficient large-scale production of stem cells are to culture cells on microcarriers, either in suspension or in a packed bed bioreactor, or to culture aggregated cells in suspension. We discuss the pros and cons of these systems as well as the possibilities to use the systems for tissue culture. either of the production systems needs to be optimized to achieve an efficient production of cultured beef. It is anticipated that the optimization of large-scale cell culture as performed for other stem cells can be translated into successful protocols for bovine satellite cells resulting in resource and cost efficient cultured beef.

关键词： cultured beef microcarriers aggregated cells packed bed bioreactor cell culture

ROOT eXUDATeS FROM CANOLA eXHIBIT BIOLOGICAL NITRIFICATION INHIBITION AND ARe eFFeCTIVe IN INHIBITING AMMONIA OXIDATION IN SOIL

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Frontiers of Agricultural Science and engineering 2022年第2期9卷 177-186页

作者： Cathryn A.O'SULLIVAN elliott G.DUNCAN Margaret M.ROPeR Alan e.RICHARDSON John A.KIRKeGAARD mark B.PeOPLeS CSIRO Agriculture&Food 306 Carmody RdSt LuciaQld 4067Australia CSIRO Agriculture&Food Private Bag 5WembleyWA 6913Australia MBS environmental 4 Cook StreetWest PerthWA 6005Australia CSIRO Agriculture&Food GPO Box 1700CanberraACT 2601Australia

A range of plant species produce root exudates that inhibit ammonia-oxidizing *** biological nitrification inhibition(BNI)capacity can decrease N loss and increase N uptake from the *** study sought evidence for the existence and magnitude of BNI capacity in canola(Brassica napus).Seedlings of three canola cultivars,Brachiaria humidicola(BNI positive)and wheat(Triticum aestivum)were grown in a hydroponic *** exudates were collected and their inhibition of the ammonia oxidizing bacterium,Nitrosospira multiformis,was *** pot experiments were used to test the inhibition of native nitrifying communities in *** exudates from canola significantly reduced nitrification rates of both *** cultures and native soil microbial *** level of nitrification inhibition across the three cultivars was similar to the well-studied high-BNI species *** capacity of canola may have implications for the N dynamics in farming systems and the N uptake efficiency of crops in rotational farming *** reducing nitrification rates canola crops may decrease N losses,increase plant N uptake and encourage microbial N immobilization and subsequently increase the pool of organic N that is available for mineralization during the following cereal crops.

关键词： ammonia oxidizing microorganisms biological nitrification inhibition farming rotations nitrogen cycling nitrogen use efficiency