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Constitutive modeling of ultra?fine?grained titanium flow stress for machining temperature prediction

Bio-Design and Manufacturing 2019年第3期2卷 153-160页

作者： Jinqiang Ning Vinh Nguyen Yong Huang karl t.hartwig Steven Y.Liang George W.Woodruff School of Mechanical Engineering Georgia Institute of Technology801 Ferst DriveAtlantaGA 30332USA Department of Mechanical and Aerospace Engineering University of Florida231 MAE-AP.O.Box 116250GainesvilleFL 32611USA Department of Mechanical Engineering Texas A&M University3123 TAMUCollege StationTX 77843?3123USA

this work investigates the machining temperatures of ultra-fine-grained titanium(UFG ti),prepared by equal channel angular extrusion,through analytical *** ti has great usefulness in biomedical applications because of its high mechanical strength,sufficient manufacturability,and high *** temperatures were predicted using a physics-based predictive model based on material constitutive relation and mechanics of the orthogonal cutting *** minimization between the stress calculated using Johnson–Cook constitutive model and the same stress calculated using mechanics model yields the estimation of machining temperatures at two deformation *** agreements are observed upon validation to the values reported in the *** machinability of UFG ti is investigated by comparing its machining temperature to that of ti–6Al–4V alloy under the same cutting *** lower temperatures are observed in machining UFG *** computational efficiency of the presented model is investigated by comparing its average computational time(~0.5 s)to that of a widely used modified chip formation model(8900 s)with comparable prediction *** work extends the applicability of the presented temperature model to a broader class of materials,specifically ultra-fine-grained *** high computational efficiency allows the in situ temperature prediction and optimization of temperature condition with process parameters planning.

关键词： Ultra-fine-grained titanium Analytical modeling High computational efficiency Johnson–Cook model Cutting mechanics

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Microglia:a promising therapeutic target in spinal cord injury

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Neural Regeneration Research 2025年第2期20卷 454-463页

作者： Xiaowei Zha Guoli Zheng thomas Skutella karl Kiening Andreas Unterberg Alexander Younsi Department of Neurosurgery Heidelberg University HospitalHeidelbergGermany Department of Neuroanatomy Institute for Anatomy and Cell BiologyHeidelberg UniversityHeidelbergGermany

Microglia are present throughout the central nervous system and are vital in neural repair,nutrition,phagocytosis,immunological regulation,and maintaining neuronal *** a healthy spinal cord,microglia are accountable for immune surveillance,however,when a spinal cord injury occurs,the microenvironment drastically changes,leading to glial scars and failed axonal *** this context,microglia vary their gene and protein expression during activation,and proliferation in reaction to the injury,influencing injury responses both favorably and unfavorably.A dynamic and multifaceted injury response is mediated by microglia,which interact directly with neurons,astrocytes,oligodendrocytes,and neural stem/progenitor *** a clear understanding of their essential nature and origin,the mechanisms of action and new functions of microglia in spinal cord injury require extensive *** review summarizes current studies on microglial genesis,physiological function,and pathological state,highlights their crucial roles in spinal cord injury,and proposes microglia as a therapeutic target.

关键词： astrocytes cytokines functional recovery immune regulation M1/M2 activation macrophages microglia neuroinflammation spinal cord injury therapy

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Analyzing the effect of earthquakes on OpenStreetMap contribution patterns and tweeting activities

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Geo-Spatial Information Science 2018年第3期21卷 195-212页

作者： Ahmed Ahmouda hartwig H.Hochmair Sreten Cvetojevic Geomatics Program Fort Lauderdale Research and Education CenterUniversity of FloridaFloridaFort LauderdaleUSA

Natural disasters,such as wildfires,earthquakes,landslides,or floods,lead to an increase in topical information shared on social media and in increased mapping activities in volunteered geographic information(VGI)*** earthquakes in Nepal and Central Italy as case studies,this research analyzes the effects of natural disasters on short-term(weeks)and longer-term(half year)changes in OpenStreetMap(OSM)mapping behavior and tweet activities in the affected *** increase of activities in OSM during the events can be partially attributed to those focused OSM mapping campaigns,for example,through the Humanitarian OSM team(HOt).Using source tags in OSM change-sets,it was found that only a small portion of external mappers actually travels to the affected regions,whereas the majority of external mappers relies on desktop mapping ***,the study analyzes the spatio-temporal sequence of posted tweets together with keyword filters to identify a subset of users who most likely traveled to the affected regions for support and rescue *** also explores where,geographically,earthquake information spreads within social networks.

关键词： Volunteered geographic information(VGI) OpenStreetMap(OSM) twitter natural disaster human dynamics

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Where to catch'em all?-a geographic analysis of Pokémon Go locations

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Geo-Spatial Information Science 2017年第3期20卷 241-251页

作者： Levente Juhász hartwig H.Hochmair Geomatics Program University of FloridaFort LauderdaleFLUSA

In 2016,Niantic Labs released Pokémon Go,an augmented reality smartphone game that attracted millions of users *** game allows users to“catch”Pokémons through their mobile cameras in different geographic locations that often correspond to prominent *** paper analyzes the distribution of PokéStops,Pokémon gyms,and spawnpoints in selected urban areas of South Florida and *** identifies which socioeconomic variables and landuse categories affect the density of PokéStops,and how PokéStops and gyms cluster relative to each *** nearest neighbor analysis,this paper assesses also how actual PokéStop locations are reflected in Yelp’s“PokéStop nearby”*** show that black and Hispanic neighborhoods are disadvantaged when it comes to crowd-sourced data coverage,that PokéStops occur more frequently in commercial,recreational and touristic sites and around universities,and that PokéStops tend to cluster around *** latter suggests that these point sets were generated by a similar location selection *** mitigate geographically linked biases,future versions of augmented reality and geo-games should aim to make them equally accessible in all areas,for example by placing extra resources,such as points of interest,in neighborhoods that are currently underrepresented in data coverage.

关键词： Pokémon Go VGI(Volunteered Geographic Information) Yelp cluster South Florida Boston HCl(human-computer interaction)

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transport mechanism in chemically reactive hybrid nanofluid flow containing gyrotactic micro-organisms over a curved oscillatory surface

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 177-192页

作者： M.NAVEED M.IMRAN t.ASGHAR Z.ABBAS Department of Mathematics Division of Science and TechnologyUniversity of Education Department of Mathematics The Islamia University of Bahawalpur

this paper examines the transport analysis, including both heat transfer and mass transfer, in hybrid nanofluid flow containing gyrotactic microorganisms towards a curved oscillatory surface. the influence of magnetic fields is also inspected in terms of their physical characteristics. to depict the phenomena of transport, modified versions of both Fick's and Fourier's laws are used. Additionally, the characteristics of both heterogeneous and homogeneous chemical reactions are also incorporated. Utilizing a curvilinear coordinate system, the flow problem is formulated as partial differential equations(PDEs)for momentum, concentration, microorganism field, and energy. An analytical solution to the obtained flow equations is achieved utilizing the homotopy analysis method(HAM).the effects of significant flow parameters on the pressure and microorganism fields, velocity, oscillation velocity, concentration, and temperature distributions are shown via graphs. Furthermore, the variations in skin friction, mass transfer rate, heat transfer rate, and local motile number due to different involved parameters are presented in tables and are analyzed in detail. Graphical results indicate that the curves of velocity and temperature fields are enhanced as the values of the solid volume fraction variables *** is also verified that the concentration rate field decreases as the values of the homogeneous reaction strength parameter and the radius of curvature parameter increase, and it increases with the Schmidt number and the heterogeneous reaction strength *** outcomes show a favorable response of the motile number to advanced values of the Peclet number, the Schmidt number, the microorganism difference parameter, and the bio-convective Lewis number.

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Prediction and Validation of Promoters Involved in the Abscisic Acid Response in Physcomitrella patens

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Molecular Plant 2011年第4期4卷 713-729页

作者： Gerrit timmerhaus Sebastian t. Hanke karl Buchta Stefan A. Rensing Faculty of Biology University of Freiburg Hauptstr. 1 79104 Freiburg Germany Present address: Nofima Marin Postboks 5010 1432/ks Norway Freiburg Initiative for Systems Biology (FRISYS) Faculty of Biology University of Freiburg Schanzlestr. 1 79104 Erelburg Germany Centre for Biological Signalling Studies (BIOSS) University of Freiburg Albertstr. 19 79104 Freiburg Germany

Detection of cis-regulatory elements, such as transcription factor binding sites （tFBS）, through utilization of ortholog conservation is possible only if genomic data from closely related organisms are available. An alternative approach is the detection of tFBS based on their overrepresentation in promoters of co-regulated genes. However, this approach usually suffers from a high rate of false-positive prediction. Here, we have conducted a case study using promoters of genes known to be strongly induced by the phytohormone abscisic acid （ABA） in the model plant Physcomitrella patens, a moss. Putative tFBS were detected using three de novo motif detection tools in a strict consensus approach. the resulting motifs were validated using data from microarray expression profiling and were able to predict ABA-induced genes with high specificity （90.48%） at mediocre sensitivity （33.33%）. In addition, 27 genes predicted to contain ABA-responsive tFBS were validated using real-time PCR. Here, a total of 37% of the genes could be shown to be induced upon ABA treatment, while 70% were found to be regulated by ABA. We conclude that the consensus approach for motif detection using coregulation information can be used to identify genes that are regulated under a given stimulus. In terms of evolution, we find that the ABA response has apparently been conserved since the first land plants on the level of families involved in transcriptional regulation.

关键词： Hormone biology bioinformatics comparative genomics gene expression transcriptional control and tran-scription factors bryophytes.

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the feasibility of coating by cooling crystallization on ibuprofen naked tablets

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Frontiers of Chemical Science and Engineering 2017年第2期11卷 211-219页

作者： Fatima Mameri Ouahiba Koutchoukali Mohamed Bouhelassa Anne hartwig Leila Nemdili Joachim Ulrich University Constantine 3 Engineering Faculty of Pharmaceutical Processes 25000 Constantine Algeria Martin Luther University Halle-Wittenberg Center of Engineering Science Thermal Process Engineering D-06099 Halle Germany

Sugar spray coating is a frequently used process in the pharmaceutical industry. However, this process presents the disadvantage to form an amorphous coating around the active ingredient. A crystalline coating formed on the surface of a tablet is highly desirable. Recently, a new process of coating by cooling crystallization has been developed and applied on bisacodyl pastilles obtained by melt crystallization. In this work, we investigated the feasibility of coating by cooling crystallization on ibuprofen ＂naked tablets＂ manufactured by compression. In the first part of this work, the solubility and the metastable zone width have been determined experimentally for the coating solution because they are essential factors for any crystallization process. In the second part, the coating process is investigated on the operating conditions that affect the surface morphology and the crystal growth rate. these experimental conditions include concentration of the coating solution, degree of sub-cooling, agitation speed, retention time, and surface properties of the naked ibuprofen tablets. the results show that naked tablet coating by cooling crystallization is feasible and can be applied in the pharmaceutical industry.

关键词： coating solution crystallization ibuprofen tablets sucrose

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Dedicated to Professor Dr.-Ing. ***.h.c. Jurgen Zierep for his 80^(th) birthday Pattern Formation in Rotating Fluids

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Journal of thermal Science 2009年第2期18卷 109-118页

作者： karl Bühler Department of Mechanical and Process Engineering University of Applied Sciences

Flows in nature and technology are often associated with specific structures and pattern. this paper deals with thedevelopment and behaviour of such flow pattern. Flow structures are important for the mass, momentum and energytransport. the behaviour of different flow pattern is used by engineers to obtain an efficient mass and energyconsumption. Mechanical power is transmitted via the momentum of rotating machine parts. therefore thephysical and mathematical knowledge of these basic concepts is important. theoretical and experimental investigationsof principle experiments are described in the following. We start with the classical problem of the flowbetween two concentric cylinders where the inner cylinder rotates. Periodic instabilities occur which are calledtaylor vortices. the analogy between the cylindrical gap flow, the heat transfer in a horizontal fluid layer exposedto the gravity field and the boundary layer flow along concave boundaries concerning their stability behaviour isaddressed. the vortex breakdown phenomenon in a cylinder with rotating cover is also described. A generalizationto spherical sectors leads then to investigations with different boundary conditions. the spherical gap flowexhibits interesting phenomena concerning the nonlinear character of the Navier-Stokes equations. Multiple solutionsin the nonlinear regime give rise to different routes during the laminar-turbulent transition. the interactionof two rotating spheres results in flow structures with separation and stagnation lines. Experimental results areconfirmed by numerical simulations.

关键词： Rotating Fluids Stability Behaviour Bifurcation Vortices Laminar-turbulent transition

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Fecal microbiota transplantation in allergic diseases

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World Journal of Methodology 2025年第2期15卷 83-91页

作者： Ece tüsüzÖnata ÖnerÖzdemir Division of Pediatric Allergy and Immunology Medical FacultySakarya UniversityAdapazarı54100SakaryaTürkiye

Microorganisms such as bacteria,fungi,viruses,parasites living in the human intestine constitute the human intestinal *** refers to composi-tional and quantitative changes that negatively affect healthy gut *** recent years,with the demonstration that many diseases are associated with dysbiosis,treatment strategies targeting the correction of dysbiosis in the treat-ment of these diseases have begun to be *** microbiota trans-plantation(FMt)is the process of transferring faeces from a healthy donor to another recipient in order to restore the gut microbiota and provide a therapeutic *** studies have gained popularity after probiotic,prebiotic,symbiotic studies in the treatment of dysbiosis and related *** has emerged as a potential new therapy in the treatment of allergic diseases as it is associated with the maintenance of intestinal microbiota and immunological balance(t helper 1/t helper 2 cells)and thus suppression of allergic *** this article,the definition,application,safety and use of FMt in allergic diseases will be discussed with current data.

关键词： Microbiota Dysbiosis Faecal microbiota transplantation Allergic diseases

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Insect Science 2008年第4期15卷 369-374页

作者： karl Kral Institute of Zoology KarI-Franzens-University Graz A-8010 Graz Austria

the peering-jump behavior was studied for the common field grasshopper Chorthippus brunneus, the meadow grasshopper C. parallelus and the alpine grasshopper Miramella alpina （Orthoptera, Caelifera）. It was found that immediately before jumping M. alpina executes primarily unilateral object-related peering movements, with approximately twice the amplitude and velocity of the predominantly bilateral object-related peering movements of the other two species. Whereas M. alpina almost always jumped toward the black stripes in the experimental arena, the other species jumped toward both the black stripes and the white spaces between them. All three species preferred the same pattern of black stripes, which permitted them to view one black stripe frontally, with an additional black stripe to the left and right, in the lateral visual field. the similarities and differences in the peering-jump behavior of the three grasshopper species is discussed with regard to visual perception （parallax cues） and environmental adaptation.

关键词： Chorthippus environmental adaptation grasshopper jumping Miramella,peering phototaxis scototaxis

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