Texas A&M University

About: Texas A&M University is a education organization based out in College Station, Texas, United States. It is known for research contribution in the topics: Population & Gene. The organization has 72169 authors who have published 164372 publications receiving 5764236 citations.

Tropical tropopause layer

Abstract: [1] Observations of temperature, winds, and atmospheric trace gases suggest that the transition from troposphere to stratosphere occurs in a layer, rather than at a sharp “tropopause.” In the tropics, this layer is often called the “tropical tropopause layer” (TTL). We present an overview of observations in the TTL and discuss the radiative, dynamical, and chemical processes that lead to its time-varying, three-dimensional structure. We present a synthesis definition with a bottom at 150 hPa, 355 K, 14 km (pressure, potential temperature, and altitude) and a top at 70 hPa, 425 K, 18.5 km. Laterally, the TTL is bounded by the position of the subtropical jets. We highlight recent progress in understanding of the TTL but emphasize that a number of processes, notably deep, possibly overshooting convection, remain not well understood. The TTL acts in many ways as a “gate” to the stratosphere, and understanding all relevant processes is of great importance for reliable predictions of future stratospheric ozone and climate.

Supramolecular arrays based on dimetal building units.

Abstract: Supramolecular chemistry is today a major thrust area, a significant part of which is based on the use of metal atoms or ions as key elements in promoting the assembly of and dictating the main structural features of the supramolecular products. Most of the work has been done with single metal atoms or ions in this role, but considerable success has already been achieved by employing M−M bonded dimetal entities instead. We review here the work done in our laboratory. Metal−metal bonded cationic complexes of the [M2(DAniF)n(MeCN)8-2n](4-n)+ type, where M = Mo or Rh and DAniF is an N,N‘-di-p-anisylformamidinate anion, have been used as subunit precursors and then linked by various equatorial and axial bridging groups such as polycarboxylate anions, polypyridyls, and polynitriles. Characterization of the products by single-crystal X-ray diffraction, CV, DPV, NMR, and other spectroscopic techniques has revealed the presence of discrete tetranuclear (pairs or loops), hexanuclear (triangles), octanuclear (squar...

Nanocomposite hydrogels for biomedical applications.

Abstract: Hydrogels mimic native tissue microenvironment due to their porous and hydrated molecular structure. An emerging approach to reinforce polymeric hydrogels and to include multiple functionalities focuses on incorporating nanoparticles within the hydrogel network. A wide range of nanoparticles, such as carbon-based, polymeric, ceramic, and metallic nanomaterials can be integrated within the hydrogel networks to obtain nanocomposites with superior properties and tailored functionality. Nanocomposite hydrogels can be engineered to possess superior physical, chemical, electrical, and biological properties. This review focuses on the most recent developments in the field of nanocomposite hydrogels with emphasis on biomedical and pharmaceutical applications. In particular, we discuss synthesis and fabrication of nanocomposite hydrogels, examine their current limitations and conclude with future directions in designing more advanced nanocomposite hydrogels for biomedical and biotechnological applications.

The Finite Element Method in Heat Transfer and Fluid Dynamics

Abstract: EQUATIONS OF HEAT TRANSFER AND FLUID MECHANICS Present Study Governing Equations of a Continuum Governing Equations in Terms of Primitive Variables Porous Flow Equations Auxiliary Transport Equations sChemically Reacting Systems Boundary Conditions sChange of Phase Enclosure Radiation Summary of Equations THE FINITE ELEMENT METHOD: AN OVERVIEW Model Differential Equation Finite Element Approximation Weighted-Integral Statements and Weak Forms Finite Element Model Interpolation Functions Assembly of Elements Time-Dependent Problems Axisymmetric Problems Convective Boundary Conditions Library of Finite Elements Numerical Integration Modeling Considerations Illustrative Examples 3D CONDUCTION HEAT TRANSFER Semidiscrete Finite Element Model Interpolation Functions Numerical Integration Computation of Surface Fluxes Semidiscrete Finite Element Model Solution of Nonlinear Equations Radiation Solution Algorithms Variable Properties sPost-Processing Operations sAdvanced Topics in Conduction sExamples of Diffusion Problems VISCOUS INCOMPRESSIBLE FLOWS Mixed Finite Element Model Penalty Finite Element Models Finite Element Models of Porous Flow Computational Considerations Solution of Nonlinear Equations Time-Approximation Schemes sStabilized Methods Post-Processing sAdvanced Topics Advanced Topics - Turbulence Numerical Examples CONVECTIVE HEAT TRANSFER Mixed Finite Element Model Penalty Finite Element Model Finite Element Models of Porous Flow Solution Methods Convection with Change of Phase Convection with Enclosure Radiation Post-Computation of Heat Flux Advanced Topics - Turbulent Heat Transfer Advanced Topics - Chemically Reacting Systems Numerical Examples sNON-NEWTONIAN FLUIDS Governing Equations of Inelastic Fluids Finite Element Models of Inelastic Fluids Solution Methods for Inelastic Fluids Governing Equations of Viscoelastic Fluids Finite Element Model of Differential Form Finite Element Model of Integral Form Unresolved Problems Numerical Examples sCOUPLED PROBLEMS Coupled Boundary Value Problems Fluid Mechanics and Heat Transfer Solid Mechanics Electromagnetics Coupled Problems in Mechanics Implementation of Coupled Algorithms Numerical Examples sADVANCED TOPICS Parallel Processing Other Topics Note: Chapters also include an Introduction, Exercises, and References APPENDIX A: COMPUTER PROGRAM--HEATFLOW Heat Transfer and Related Problems Flows of Viscous Incompressible Fluids Description of the Input Data A Source Listings of Selective Subroutines Reference sAPPENDIX B: SOLUTION OF LINEAR EQUATIONS Introduction Direct Methods Iterative Methods References for Additional Reading sAPPENDIX C: FIXED POINT METHODS AND CONTRACTION MAPPINGS Fixed Point Theorem Chord Method Newton's Method The Newton-Raphson Method Descent Methods References for Additional Reading