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Frontiers of Structural and Civil Engineering 2018年第3期12卷 352-360页

作者： mohammed FARUQI Oved I. mATA Francisco AGUINIGA Department of Civil and Architectural Engineering Texas A&M University Kingsville TX 77843 USA

Concrete members historically have used either pre-stressed steel or steel bars. In recent years there has been an increased interest in the use of fiber reinforced polymer （FRP） materials. However, the flexure behavior of a hybrid system reinforced by the combination of pre-stressed steel and glass fiber reinforced （GFRP） is still relatively unknown. The purpose of this work is to study this. Two slabs of 100 and 150-millimeter thickness, with a span of 2.1 m reinforced with both pre-stressing steel and GFRP were constructed and tested to failure using ACI 318-11 and ACI 440.1 R-15. The concrete had strength of 31 mPa and the slabs were respectively reinforced with 5#4 bars and 3#5 bars. Each slab had 37.41 mm2 prestressing wire with a failure stress of 1722.5 mPa. The experimental flexural strength and deflection of slabs were compared with their respective sizes theoretical slabs. The theoretical slabs were either reinforced with pre-stressed steel or GFRP rebars, or a hybrid system. It was found that the hybrid system produces better results.

关键词： Partial pre-stressing composite structures GFRP bars

Laser Stimulation of the Chloroplast/Endoplasmic Reticulum Nexus in Tobacco Transiently Produces Protein Aggregates （Boluses） within the Endoplasmic Reticulum and Stimulates Local ER Remodeling

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molecular Plant 2011年第5期4卷 886-895页

作者： Lawrence R. Griffing1 3258 TAmU Biology Department Texas A＆M University College Station Texas 77843 USA

Does the ER subdomain that associates with the chloroplast in vivo, hereafter referred to as the chloroplast/ER nexus, play a role in protein flow within the ER？ In studies of tobacco cells either constitutively or transiently expressing ER-retained luminal, GFP-HDEL, or trans-membrane, YFP-RHD3, fluorescent fusion proteins, brief 405-nm （3-6-mW） laser stimulation of the nexus causes a qualitative difference in the movement and behavior of proteins in the ER. Photostimulating the nexus produces fluorescent protein punctate aggregates （boluses） within the lumen and membrane of the ER. The aggregation propagates through the membrane network throughout the cell, but within minutes can revert to normal, with disaggregation propagating back toward the originally photostimulated nexus. In the meantime, the ER grows and anastomoses around the chloroplast, forming a dense cisternal and tubular network. If this network is again photostimulated, bolus formation does not recur and, if the photostimulation results in photobleaching, fluorescence recovery after photobleaching occurs as it would typically in areas away from the nexus. Bolus propagation is not mediated by the actin cytoskeleton, but can be reversed by pre-conditioning the cells for 30 min with high, 40-45℃, temperature （heat stress）. Because it is not reversed with heat stress, the reorganization of the ER at the nexus following photostimulation is a separate event.

关键词： ER-chloroplast transport ER movement actin heat stress fluorescence recovery after photobleaching blue light reception.

BIVARIATE CUBIC B-SPLINES RELATIVE TO CROSS-CUT TRIANGULATIONS

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Chinese Annals of mathematics 1983年第4期4卷 509-523页

作者：崔锦泰王仁宏 texas a&m university USA Jilin university

In this paper we prove that there are no locally supported bivariate Gk-1spline functionsof degree k on cross-cut grid partitioned regions with no more than three lines meeting at acommon *** also give explicit expressions of bivariate C1 cubic B-spline with smallestlocal support on cross-cut triangular grid partitioned regions where each vertex is theintersection of three *** normalized,these B-splines are proved to be uniquelydetermined and form a partition of ***,the corresponding waxationdiminishing bivariate spline operators are proved to preserve all linear polynomials of *** facts enable us to give error estimates for approximation by bivariate C1cubic splines for functions of class C,C1 and C2.

关键词： BIVARIATE CUBIC B-SPLINES RELATIVE TO CROSS-CUT TRIANGULATIONS 一夕

Relative preference of Lygus hesperus （Hemiptera： miridae） to selected host plants in the field

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Insect Science 2010年第6期17卷 542-548页

作者： Apurba K. Barman megha N. Parajulee Stanley C. Carroll Department of Entomology Texas A&M University College Station texas AgriLife Research Center Lubbock Texas USA

Information on host plant preference of agriculturally important insect pests, such as Lygus hesperus （Knight）, can be helpful in predicting its occurrence and future movement among crop and nonrop host plants. A field study was conducted during 2005 and 2006 to evaluate the host preference of Lygus to cotton and four other host plants in the texas High Plains, including alfalfa （medicago sativa L.）, wild sunflower （Helianthus annuus L.）, Russian thistle （Salsola iberica L.） and pigweed （Amaranthus palmeri L.）. Sampling for both nymphs and adults during 2005 （July to November） and 2006 （June to November） showed that alfalfa and Russian thistle were the two most preferred hosts out of the five hosts evaluated. Abundance of nymphs （numbers per 50 sweeps per host plant） during the sampling period also indicated the superior reproductive suitability of alfalfa and Russian thistle. Cotton appeared to be the least attractive host plant for Lygus when Russian thistle and alfalfa were available in the host mosaic. Seasonal abundance of Lygus was found to be lower during 2006 compared to 2005, which may be explained by the difference in rainfall patterns during these two years. In terms of species dominance, L. hesperus was the most dominant species in the sampled population followed by an inconsiderable fraction ofL. elisus and L. lineolaris.

关键词： cotton crop host-plant preference Lygus hesperus non-cotton crops

Spatial evolution of friction of a textured wafer surface

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Friction 2013年第1期1卷 92-97页

作者： Huaping XIAO Ke WANG Grant FOX michel BELIN Julien FONTAINE Hong LIANG mechanical Engineering Texas A&M UniversityCollege StationTexas 77843USA materials Science and Engineering Texas A&M UniversityCollege StationTexas 77843USA Ecole Centrale de Lyon/CNRS-UmR 5513 France

mechanical failure of integrated circuits and micro-electro-mechanical systems(mEmS)demands new understanding of friction in small *** present research,we demonstrated an in situ approach to measure sliding friction of a patterned surface composing multi-materials and *** effects of materials and surface morphology on friction and electrical contact resistance were *** material transfer at the interface of dissimilar materials was found to play dominating roles in *** current work provides important insights from the fundamentals of friction that benefit the design of new micro-devices.

关键词： micro-electro-mechanical systems(mEmS) patterned wafers friction transfer wear electrical contact resistance

Zinc-ion hybrid supercapacitors with ultrahigh areal and gravimetric energy densities and long cycling life

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Journal of Energy Chemistry 2022年第7期31卷 480-491,I0012页

作者： Ahmad Amiri m.Naraghi Andreas A.Polycarpou J.mike walker’66 mechanical engineering department texas a&m universitycollege stationTX 77843USA department of aerospace engineering texas a&m universitycollege stationTX 77843USA

Zinc ion hybrid supercapacitor (ZIHSC) with promising energy and power densities is an excellent answer to the ever-growing demand for energy storage *** restricted lifespan due to the dendrite formation on metallic zinc (Zn) is one of the main ***,we investigate the electrochemical capability of oxygen-enriched porous carbon nanofibers (A-CNF) and nitrogen,oxygen-enriched porous carbon nanofibers (N-CNF) cathode materials for structural *** this end,a series of samples with different chemical compositions (N and O contents) are prepared to present deep insight into the electrochemical mechanism between N/O doping and Zn-ion *** as-prepared ZIHSC in the presence of N-CNF cathode and Zn Cl_(2) electrolyte offers a battery-level gravimetric energy density of 143.2 Wh kg^(-1)at a power density of 367.1 W kg^(-1).The free-standing N-CNF electrodes in ZIHSCs enjoy delivering an outstanding areal energy density of 110.4μWh cm^(-2)at 0.24 m W cm^(-2),excellent rate capability,and noticeable cycling stability over 10,000 cycles at 10 A g^(-1)with less than 7%*** was also concluded that active pyrrolic N dopants might deliver and facilitate more pseudocapacitance in ZIHSCs than other N configurations,resulting in higher adsorption/desorption and insertion/extraction process of Zn Cl^(+).Taking advantage of the beneficial properties of a free-standing continuous cathode,this novel generation of structural cathode material offers high areal and gravimetric energy densities and mechanical properties in a single zinc-ion-based package.

关键词： Porous carbon nanofibers Zinc chloride electrolyte Zinc ion hybrid supercapacitors Nitrogen-doping Activation Energy density

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multiscale modeling and Simulations of Flows in Naturally Fractured Karst Reservoirs

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Communications in Computational Physics 2009年第6期6卷 162-184页

作者： Peter Popov Yalchin Efendiev Guan Qin Institute for Scientific Computation Texas A&M UniversityCollege StationTX 77843 Department of mathematics Texas A&M UniversityCollege StationTX 77843

modeling and numerical simulations of fractured,vuggy,porus media is a challenging problem which occurs frequently in reservoir *** problem is especially relevant in flow simulations of karst reservoirs where vugs and caves are embedded in a porous rock and are connected via fracture networks at multiple *** this paper we propose a unified approach to this problem by using the StokesBrinkman equations at the fine *** equations are capable of representing porous media such as rock as well as free flow regions(fractures,vugs,caves)in a single system of *** then consider upscaling these equations to a coarser *** cell problems,needed to compute coarse-scale permeability of Representative Element of Volume(REV)are discussed.A mixed finite element method is then used to solve the Stokes-Brinkman equation at the fine scale for a number of flow problems,representative for different types of vuggy *** is also performed by numerical solutions of Stokes-Brinkman cell problems in selected *** isolated vugs in porous matrix as well as vugs connected by fracture networks are analyzed by comparing fine-scale and coarse-scale flow *** different types of fracture networks,representative of short-and long-range fractures are studied *** is also shown that the Stokes-Brinkman equations can naturally be used to model additional physical effects pertaining to vugular media such as partial fracture with fill-in by some material and/or fluids with suspended solid particles.

关键词： Homogenization Stokes equation Brinkman equation porous media

Heat Transfer Optimization for Air-mist Cooling between a Stack of Parallel Plates

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Journal of Thermal Science 2010年第3期19卷 253-260页

作者： Roy J.Issa mechanical Engineering Division Department of Engineering and Computer Science West Texas A&M University CanyonTexas 79016USA

A theoretical model is developed to predict the upper limit heat transfer between a stack of parallel plates subject to multiphase cooling by air-mist *** model predicts the optimal separation distance between the plates based on the development of the boundary layers for small and large separation distances,and for dilute mist *** results show the optimal separation distance to be strongly dependent on the liquid-to-air mass flow rate loading ratio,and reach a limit for a critical *** these dilute spray conditions,complete evaporation of the droplets takes *** results also show the optimal separation distance decreases with the increase in the mist flow *** proposed theoretical model shall lead to a better understanding of the design of fins spacing in heat exchangers where multiphase spray cooling is used.

关键词： Air-mist multiphase Heat transfer Liquid-to-air loading

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The production of carbon nanotubes from carbon dioxide:challenges and opportunities

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Journal of Natural Gas Chemistry 2010年第5期19卷 453-460页

作者： Geoffrey S.Simate Sunny E.Iyuke Sehliselo Ndlovu Clarence S.Yah Lubinda F.Walubita School of Chemical and metallurgical Engineering University of the Witwatersrand TTI-texas a&m university System College Station

Recent advances in the production of carbon nanotubes （CNTs） are reviewed with an emphasis on the use of carbon dioxide （CO2） as a sole source of carbon. Compared to the most widely used carbon precursors such as graphite, methane, acetylene, ethanol, ethylene, and coal-derived hydrocarbons, CO2 is competitively cheaper with relatively high carbon yield content. However, CNT synthesis from CO2 is a newly emerging technology, and hence it needs to be ex- plored further. A theoretical and analytical comparison of the cur- rently existing CNT-CO2 synthesis techniques is given including a review of some of the process parameters （i.e., temperature, pres- sure, catalyst, etc.） that affect the CO2 reduction rate. Such analysis indicates that there is still a fundamental need to further explore the following aspects so as to realize the full potential of CO2 based CNT technology：（1） the CNT-CO2 synthesis and formation mechanism, （2） catalytic effects of transitional metals and mechanisms, （3） uti- lization of metallocenes in the CNT-CO2 reactions, （4） applicability of ferrite-organometallic compounds in the CNT-CO2 synthesis reactions, and （5） the effects of process parameters such as temperature, etc.

关键词： supercritical CO2 CO2 reduction chemical vapour decomposition(CVD) carbon nanotubes ferrite catalysts

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Experimental investigation of multiphase flow behavior in drilling annuli using high speed visualization technique

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Frontiers in Energy 2020年第3期14卷 635-643页

作者： Alap Ali ZAHID Syed Raza ur REHmAN S.RUSHD Anwarul HASAN mohammad Azizur RAHmAN Department of mechanical Engineering College of EngineeringQatar UniversityDoha 2713Qatar Petroleum Engineering Program Texas A&M University at QatarDoha 23874Qatar

Imaging with high definition video camera is an important technique to visualize the drilling conditions and to study the physics of complex multiphase flow associated with the hole cleaning *** main advantage of visualizing multiphase flow in a drilling annulus is that the viewer can easily distinguish fluid phases,flow patterns and thicknesses of cutting *** this paper the hole cleaning process which involves the transportation of cuttings through a horizontal annulus was *** two-phase(solid-liquid)and the three-phase(solid-liquid-gas)flow conditions involved in this kind of annular transportation were experimentally simulated and images were taken using a high definition *** the captured images,a number of important parameters like velocities of different phases,heights of solid beds and sizes of gas bubbles were *** different techniques based on an image analysis software and mATLAB coding were used for the *** results were compared to validate the image analyzing *** visualization technique developed in this paper has a direct application in investigating the critical conditions required for efficient hole cleaning as well as in optimizing the mud program during both planning and operational phases of ***,it would be useful in predicting the cuttings transport performance,estimating solid bed height,gas bubble size,and mean velocities of bubbles/particles.

关键词： visualization horizontal annulus hole cleaning multiphase flow image analysis flow regime