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Biomedical and Environmental Sciences 2018年第2期31卷 149-154页

作者： samuel t.ogundare Olubunmi G.Fasanmi Folorunso O.Fasina Department of Production Animal Studies Faculty of Veterinary Science University of Pretoria Federal College of Animal Health and Production technology Moor Plantation Emergency Centre for transboundary Animal Diseases (ECtAD) Food and Agriculture Organisation of the United Nations (FAO)

Enterotoxigenic Escherichio coli （EtEC） causes neonatal and post-weaning diarrhea in pigs. In order to determine the risk factors, rectal/fecal swabs and visceral organs obtained from pig farms in two regions of South Africa were analyzed microbiologically against risk variables. Seventy-two percent of young pigs were found to be positive for EtEC toxin genes; estB （38.9%）, estB/StAP （25%）, and estB/Lt （13.9%） were dominant. Risk factors for EtEC-diarrhea in pigs include： leaving sick piglets in a pen with healthy piglets [odds ratio （OR） = 33.52; P 〈 0.0001]; water spillage in pen （OR = 42.87; P 〈 0.0001）; hypothermic piglets （OR = 7.29; P 〈 0.0001）; runt piglets in pen with healthy littermates （OR = 3.65; P 〈 0.0001）; and prolonged use of antibiotics （OR = 3.05; P = 0.05）.

关键词： South Africa in Diarrheic and Non-diarrheic Neonatal and Weaner Pigs Risk Factors for Prevalence of Enterotoxigenic Escherichia coli

Atmospheric Corrosion Studies of Ductile Iron and Austenitic Stainless Steel in an Extreme Marine Environment

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Journal of Minerals and Materials Characterization and Engineering 2012年第9期11卷 914-918页

作者： Olasupo ogundare Babaniyi Babatope Adelana Razaq Adetunji samuel Olugbenga Oloruntoba Olusunle Department of Materials Science and Engineering ObafemiAwolowo University Ile Ife. Nigeria Department of Physics ObafemiAwolowo University Ile Ife. Nigeria National Agency for Science and Engineering Infrastructure Abuja. Nigeria Prototype Engineering Development Institute Ilesa Nigeria

this paper presents the corrosion characteristics and the accompanying changes in the microstructure of unalloyed duc-tile iron (DI) and austenitic stainless steel (ASS) in table salt medium representing an upper limit in an extreme marine environment. the individual corrosion rates of DI and ASS was evaluated for the maximum time period of 1200 hr. Using the immersion test technique, the corrosion rate of DI was evaluated and found to be four-orders of magnitude greater than that of ASS. the corrosion product morphologies of the DI showed that the nodular matrix was gradually covered up as immersion time progressed while the corrosion channels and volume of pits that initially formed in ASS respectively deepened and increased with increased exposure time. this work is important as a reference point for the quantification of the corrosion effectiveness of alloying DI. the microstructures of the corroded samples showed corro-sion initiation and gradual accumulation of corrosion products.

关键词： Atmospheric Corrosion Ductile IronL Austenitic Stainless Steel Sodium Chloride And Microstructure

Analytical modeling and simulation of germanium single gate silicon on insulator tFEt

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Journal of Semiconductors 2014年第3期35卷 25-28页

作者： t.S.Arun samuel N.B.Balamurugan Department of Electronics and Communication Engineering Thiagarajar College of Engineering

this paper proposes a new two dimensional（2D） analytical model for a germanium（Ge） single gate silicon-on-insulator tunnel field effect transistor（SG SOI tFEt）. the parabolic approximation technique is used to solve the 2D Poisson equation with suitable boundary conditions and analytical expressions are derived for the surfacepotential,*** is derived further by using the electric fields. the results show that Ge based tFEts have significant improvements ***heanalytical model results with the technology computer aided design（tCAD） simulation results and also comparing them with results from a silicon based tFEt.

关键词： tunnel field effect transistor(tFEt) analytical modelling Poisson equation surface potential electric field

Antipredatory call behavior of lapwing species in an Afrotropical environment

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Avian Research 2023年第4期14卷 630-639页

作者： Fatima R.James Chioma I.Okafor samuel t.Osinubi Shiiwua A.Manu samuel Ivande taiwo C.Omotoriogun A.p.leventis ornithological research institute university of josp.o.box 13404josplateau statenigeria eden creation care initiative rennajj fish farm p.o.box 7173josplateau statenigeria fitzpatrick institute of african ornithology university of cape towncape townsouth africa department of zoology university of josjosplateau statenigeria biotechnology unit department of biological scienceselizade universityp.m.2.002ilara-mokinondo statenigeria natural history museum university of oslop.o.box 1172 blindern0318 oslonorway

Predation is an important source of natural selection on prey species and has resulted in adaptations such as antipredator vocal signals,which can alert others to the presence of predators and solicit cooperative *** vocal alarm signals of birds have been well studied,they are poorly known in tropical African *** address this lack of information,the antipredatory signals and responses of two lapwings(Wattled Lapwing Vanellus senegallus and Spur-winged Lapwing Vanellus spinosus)to potential predators were investigated using data collected from focal observation,distance measurements,focal recordings,and playback *** lapwing calls elicited to predators were classified as alarm or mobbing calls based on whether the calls elicited alert behavior or attack from other *** linear analysis(DLA)was used to compare the time and frequency parameters of the call types measured in Raven ***,lapwings’responses to intruders,alert and start distance,time of day,and latency,as well as the effects of flock size and distance to cover were *** 48%of all calls was correctly classified by *** best predictors of call type for the lapwings were maximum frequency and high *** alarm and mobbing calls were elicited by African Wattled Lapwings to dogs and *** calls were elicited to intruders by the Spur-winged *** distance was positively associated with start distance,and differed between morning and evening in both *** scarce information from tropical Africa,this study put in perspective vocal and antipredator behavior of lapwing species in Africa.

关键词： Acoustic Alarm calls Lapwings Mobbing calls Vocal signals

Laboratory study of fluid properties owing to cutting intrusions during horizontal directional drilling

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Underground Space 2020年第1期5卷 20-29页

作者： Pinghe Sun Dingqiang Mo samuel t.Ariaratnam Han Cao Pengfei Zhang School of Geosciences and Information Physics Central South UniversityChangsha 410083China Key Laboratory of Metallogenic Prediction and Geoenvironmental Monitoring of Ministry of Education Central South UniversityChangsha 410083China School of Sustainable Engineering&the Built Environment Arizona State UniversityP.O.Box 873005TempeAZUSA State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengduChina

During horizontal directional drilling installations,a primary function of drilling fluids is to yield drill cuttings and lubricate the product *** paper presents the results of a research study of drilling fluid parameters,and the filter cake properties associated with drill cutting *** sand meshes and field cutting sizes were added to the drilling *** on the laboratory experiments of eighteen samples including testing drilling fluid rheology and filter cake properties,the influence of drill cuttings on low solid-phase drilling fluid systems were *** results reveal that drilling fluid plastic viscosity values increase with sand content and particle *** 100-mesh sand exhibits a larger plastic viscosity compared to the 200-mesh *** suggests that the coarser the sand,the greater is the plastic *** contrast,drilling fluids with 200-mesh sand exhibit greater shear forces than the 100-mesh *** the sand content is4%,the shear dilution ability of the drilling fluid begins to *** thinnest filter cake is formed after 6 h with a 100-mesh cutting size and 4%sand ***,when the cutting size changed to 150-mesh and 2%content,the largest filter cake toughness and strength after rolling for 12 h were ***,the combination of 200-mesh and 150-mesh with 2%–4%content rolling for 12–24 h indicate different *** the filter cake thickness,cutting content is the primary influencing factor followed by particle size and *** factor with the least influence is rolling *** found that rolling time and gradation were the most significant factors affecting the toughness of the filter cake,followed by cutting ***,particle size exhibits the least influence on filter cake *** results are important to better understand the solid-phase control of drilling fluids in the field.

关键词： Drilling fluid Filter cake Drilling cutting Solid-phase control Rheology Horizontal directional drilling

Determination of the magnetic fields of Magellanic X-ray pulsars

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Research in Astronomy and Astrophysics 2017年第6期17卷 95-100页

作者： Dimitris M. Christodoulou Silas G. t. Laycock Jun Yang samuel Fingerman Lowell Center for Space Science and technology University of Massachusetts Lowell Lowell MA 01854 USA Department of Mathematical Sciences University of Massachusetts Lowell Lowell MA 01854 USA Department of Physics & Applied Physics University of Massachusetts Lowell Lowell MA 01854 USA

the 80 high-mass X-ray binary （HMXB） pulsars that are known to reside in the Magellanic Clouds （MCs） have been observed by the XMM-Newton and Chandra X-ray telescopes on a regular basis for 15 years, and the XMM-Newton and Chandra archives contain nearly complete information about the duty cycles of the sources with spin periods Ps 〈 100 s. We have reprocessed the archival data from both observatories and we combined the output products with all the published observations of 31 MC pulsars with Ps 〈 100 s in an attempt to investigate the faintest X-ray emission states of these objects that occur when accretion to the polar caps proceeds at the smallest possible rates. these states determine the so-called propeller lines of the accreting pulsars and yield information about the magnitudes of their surface magnetic fields. We have found that the faintest states of the pulsars segregate into five discrete groups which obey to a high degree of accuracy the theoretical relation between spin period and X-ray luminosity. So the entire population of these pulsars can be described by just five propeller lines and the five corresponding magnetic moments （0.29, 0.53, 1.2, 2.9 and 7.3, in units of 1030 G cma）.

关键词： Magellanic clouds - accretion, accretion disks - stars magnetic field - stars neutron- X-rays binaries

COMPARISON OF EMIttED EMISSIONS BEtWEEN tRENCHLESS PIPE REPLACEMENt AND OPEN CUt UtILItY CONStRUCtION

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Journal of Green Building 2009年第2期4卷 126-140页

作者： samuel t.Ariaratnam Shaik S.Sihabuddin Ira A.Fulton School of Engineering Arizona State UniversityTempeAZ Metcalf Builders Inc. 751 Basque WayCarson CityNV

Currently,there is a worldwide trend towards reducing emissions into the environment generated by human *** emissions into the atmosphere are a major measure of the impact on *** construction indus-try is a major producer of such emissions due in part to the magnitude of operations and the vast array of *** urbanization has resulted in a need for the installation of an expanded underground network of infrastruc-ture that includes gas,water,wastewater,pipelines,power,and communications ***,engineers are faced with engaging the construction option that not only provides the best cost advantage,but also considers environmental sensitivities to create the most sustainable *** of pollutants such as carbon dioxide(CO_(2)),carbon monoxide(CO),nitrogen oxide(NO_(X)),total organic compounds(tOC),and sulfur oxide(SO_(X))have been identiﬁed by the United States Environmental Protection Agency as critical to sustainable *** paper describes an approach for quantifying airborne emissions that is demonstrated through a comparison of two construction methods for installing a wastewater *** was discovered that the option involving a traditional open cut method resulted in an overall average of about 80%greater emissions compared to trenchless pipe ***ﬁndings of this paper should assist the utility construction industry in technology selection to minimize environmental impacts.

关键词： environmental trenchless technology emissions underground construction

Kinematic Analysis of an Under-actuated,Closed-loop Front-end Assembly of a Dragline Manipulator

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International Journal of Automation and computing 2020年第4期17卷 527-538页

作者： Muhammad AWardeh samuel Frimpong Department of Mining and Nuclear Engineering Missouri University of Science and TechnologyRolla 65409USA Center for Infrastructure Engineering Studies Missouri University of Science and TechnologyRolla 65409USADepartment of Mining and Nuclear EngineeringMissouri University of Science and TechnologyRolla 65409USA

Dragline excavators are closed-loop mining manipulators that operate using a rigid multilink framework and rope and rigging system,which constitute its front-end *** arrangements of dragline front-end assembly provide the necessary motion of the dragline bucket within its operating *** assembly resembles a five-link closed kinematic chain that has two independent generalized coordinates of drag and hoist ropes and one dependent generalized coordinate of dump *** models failed to represent the actual closed loop of dragline front-end assembly,nor did they describe the maneuverability of dragline ropes under imposed geometric ***,a three degrees of freedom kinematic model of the dragline front-end is developed using the concept of generalized *** contains all relevant configuration and kinematic constraint conditions to perform complete digging and swinging *** model also uses three inputs of hoist and drag ropes linear and a rotational displacement of swinging along their *** inverse kinematics is resolved using a feedforward displacement algorithm coupled with the Newton-Raphson method to accurately estimate the trajectories of the *** trajectories are solved only during the digging phase and the singularity was eliminated using Baumgarte's stabilization technique(BSt),with appropriate inequality constraint *** is shown that the feedforward displacement algorithm can produce accurate trajectories without the need to manually solve the inverse kinematics from the *** research findings are well in agreement with the dragline real operational limits and they contribute to the efficiency and the reduction in machine downtime due to better control strategies of the dragline cycles.

关键词： Dragline mining manipulator underactuated closed-loop mechanism generalized speeds Baumgarte's stabilization technique(BSt) feedforward displacement

the benefits of being dominant:health correlates of male social rank and age in a marmot

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Current Zoology 2022年第1期68卷 19-26页

作者： Kenta UCHIDA Rachel NG samuel A.VYDRO Jennifer E.SMItH Daniel t.BLUMStEIN Department of Ecology&Evolutionary Biology University of CaliforniaLos AngelesCA 90095-1606USA Department of Biology Mills CollegeOaklandCA 94613USA the Rocky Mountain Biological Laboratory Crested ButteCO 81224USA

the benefits of dominance may not come without costs,particularly for *** example,the“immunocompetence handicap hypothesis”states that males with enhanced mating success allocate resources to enhance reproductive output at a cost to their current health,whereas the“resource quality hypothesis”predicts that high-ranking males may benefit from increased reproduction and good *** the predictions from each have been well tested in captive animals and in a variety of highly social primates,fewer studies have been carried out in free-living,facultatively social *** adult male yellow-bellied marmots(Marmota flaviventer),we evaluated predictions of these hypotheses by examining the relationship between social rank and 2 health indicators—fecal glucocorticoid metabolite(FCM)levels,and neutrophil/lymphocyte(N/L)ratios—after accounting for variation explained by age,body mass,and *** found that higher-ranking males tended to have a lower N/L ratio(reflecting good health)than lower-ranking individuals,whereas FCM levels were not significantly related to *** addition,heavier male marmots had lower N/L ratios,whereas body mass was not associated with FCM *** also found that older adult males had lower FCM levels(reflecting less physiological stress)but higher N/L ratios than younger ***,we found that FCM levels decreased as the active season progressed and FCM levels were associated with the time of the ***,our results suggest that socially-dominant male marmots enjoyed better,not worse health in terms of lower N/L ratios.

关键词： immunocompetence handicap hypothesis life history trade-offs N/L ratio physiological stress resource quality hypothesis

tAILING WAVEtRAIN GENERAtION IN PRECURSOR SOLItON GENERAtION IN tWO-LAYER FLOW

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Acta Mechanica Sinica 2000年第1期16卷 1-7页

作者：徐肇廷徐昊 samuel Shan-pu Shen Institute of Physical Oceanography and Physical Oceanography Lab. Ocean University of QingdaoQingdao 266003China Key Lab.of Marine Science & Numerical Modeling State Oceanic AdministrationQingdao 266003China Department of Mathematical Sciences University of Alberta EdmontonAlberta T6G 2G1Canada

A theory of tailing wavetrain generation for the precursor soliton generation in two-layer flow is presented by using averaged KdV equations (AKdV), which are derived by the authors in terms of Whitham's method of averaging([1,2]). From the AKdV equations, group velocities of the tailing wavetrain generation are obtained by means of generating conditions of the tailing wavetrains, furthermore an analytical solution of the tailing wavetrain generation is found theoretically. A comparison between the theoretical and numerical results is carried out in the present paper, which shows that the theoretical results are in good agreement with the numerical ones, obtained from the fKdV equation in two-layer flow with the depth of unity in the rest.

关键词： tailing wavetrain group velocity soliton two-layer flow