Rensselaer Polytechnic Institute

About: Rensselaer Polytechnic Institute is a education organization based out in Troy, New York, United States. It is known for research contribution in the topics: Terahertz radiation & Finite element method. The organization has 19024 authors who have published 39922 publications receiving 1414699 citations. The organization is also known as: RPI & Rensselaer Institute.

Experimental Observation of an Extremely Dark Material Made By a Low-Density Nanotube Array

Abstract: An ideal black material absorbs light perfectly at all angles and over all wavelengths. Here, we show that low-density vertically aligned carbon nanotube arrays can be engineered to have an extremely low index of refraction, as predicted recently by theory [Garcia-Vidal, F. J.; Pitarke, J. M.; Pendry, J. B. Phys. Rev. Lett. 1997, 78, 4289-4292] and, combined with the nanoscale surface roughness of the arrays, can produce a near-perfect optical absorption material. An ultralow diffused reflectance of 1 x 10(-7) measured from such arrays is an order-of-magnitude lower compared to commercial low-reflectance standard carbon. The corresponding integrated total reflectance of 0.045% from the nanotube arrays is three times lower than the lowest-ever reported values of optical reflectance from any material, making it the darkest man-made material ever.

CRC Standard Mathematical Tables and Formulae

Abstract: Numbers and Elementary Mathematics Proofs without words Constants Special numbers Number theory Series and products Algebra Elementary algebra Polynomials Vector algebra Linear and matrix algebra Abstract algebra Discrete Mathematics Set theory Combinatorics Graphs Combinatorial design theory Difference equations Geometry Euclidean geometry Coordinate systems in the plane Plane symmetries or isometries Other transformations of the plane Lines Polygons Surfaces of revolution: the torus Quadrics Spherical geometry and trigonometry Conics Special plane curves Coordinate systems in space Space symmetries or isometries Other transformations of space Direction angles and direction cosines Planes Lines in space Polyhedra Cylinders Cones Differential geometry Analysis Differential calculus Differential forms Integration Table of indefinite integrals Table of definite integrals Ordinary differential equations Partial differential equations Integral equations Tensor analysis Orthogonal coordinate systems Interval analysis Real analysis Generalized functions Complex analysis Special Functions Ceiling and floor functions Exponentiation Logarithmic functions Exponential function Trigonometric functions Circular functions and planar triangles Tables of trigonometric functions Angle conversion Inverse circular functions Hyperbolic functions Inverse hyperbolic functions Gudermannian function Orthogonal polynomials Gamma function Beta function Error functions Fresnel integrals Sine, cosine, and exponential integrals Polylogarithms Hypergeometric functions Legendre functions Bessel functions Elliptic integrals Jacobian elliptic functions Clebsch-Gordan coefficients Integral transforms: Preliminaries Fourier integral transform Discrete Fourier transform (DFT) Fast Fourier transform (FFT) Multidimensional Fourier transforms Laplace transform Hankel transform Hartley transform Mellin transform Hilbert transform Z-Transform Tables of transforms Probability and Statistics Probability theory Classical probability problems Probability distributions Queuing theory Markov chains Random number generation Control charts and reliability Statistics Confidence intervals Tests of hypotheses Linear regression Analysis of variance (ANOVA) Sample size Contingency tables Probability tables Scientific Computing Basic numerical analysis Numerical linear algebra Numerical integration and differentiation Mathematical Formulae from the Sciences Acoustics Astrophysics Atmospheric physics Atomic physics Basic mechanics Beam dynamics Classical mechanics Coordinate systems - Astronomical Coordinate systems - Terrestrial Earthquake engineering Electromagnetic transmission Electrostatics and magnetism Electronic circuits Epidemiology Finance Fluid mechanics Fuzzy logic Human body Image processing matrices Macroeconomics Modeling physical systems Optics Population genetics Quantum mechanics Quaternions Relativistic mechanics Solid mechanics Statistical mechanics Thermodynamics Miscellaneous Calendar computations Cellular automata Communication theory Control theory Computer languages Cryptography Discrete dynamical systems and chaos Electronic resources Elliptic curves Financial formulae Game theory Knot theory Lattices Moments of inertia Music Operations research Recreational mathematics Risk analysis and decision rules Signal processing Symbolic logic Units Voting power Greek alphabet Braille code Morse code List of References List of Figures List of Notation Index

Water in Nonpolar Confinement: From Nanotubes to Proteins and Beyond *

Abstract: Water molecules confined to nonpolar pores and cavities of nanoscopic dimensions exhibit highly unusual properties. Water filling is strongly cooperative, with the possible coexistence of filled and empty states and sensitivity to small perturbations of the pore polarity and solvent conditions. Confined water molecules form tightly hydrogen-bonded wires or clusters. The weak attractions to the confining wall, combined with strong interactions between water molecules, permit exceptionally rapid water flow, exceeding expectations from macroscopic hydrodynamics by several orders of magnitude. The proton mobility along 1D water wires also substantially exceeds that in the bulk. Proteins appear to exploit these unusual properties of confined water in their biological function (e.g., to ensure rapid water flow in aquaporins or to gate proton flow in proton pumps and enzymes). The unusual properties of water in nonpolar confinement are also relevant to the design of novel nanofluidic and molecular separation devices or fuel cells.

A correct and complete algorithm for the generation of mechanical assembly sequences

Abstract: The authors present an algorithm for the generation of mechanical assembly sequences and a proof of its correctness and completeness. The algorithm uses a relational model which describes the geometry of the assembly and the attachments that bind one part to another. The problem of generating the assembly sequences is transformed into the problem of generating disassembly sequences, in which the disassembly tasks are the reverse of feasible assembly tasks. This transformation leads to a decomposition approach in which the problem of disassembling one assembly is decomposed into distinct subproblems, each involving the disassembly of one subassembly. It is assumed that at each assembly task exactly two subassemblies are mated and that all contacts between the parts in the two subassemblies are established. The algorithm yields an AND/OR graph representation of assembly sequences. The correctness of the algorithm is based on the assumption that it is always possible to decide correctly whether two subassemblies can be joined based on geometrical and physical criteria. An approach to compute this decision is given, and bounds for the amount of computation required are presented. >

Automotive Electric Propulsion Systems With Reduced or No Permanent Magnets: An Overview

Abstract: Hybrid and electric vehicle technology has seen rapid development in recent years. The motor and the generator are at the heart of the vehicle drive and energy system and often utilize expensive rare-earth permanent magnet (PM) material. This paper reviews and addresses the research work that has been carried out to reduce the amount of rare-earth material that is used while maintaining the high efficiency and performance that rare-earth PM machines offer. These new machines can use either less rare-earth PM material, weaker ferrite magnets, or no magnets; and they need to meet the high performance that the more usual interior PM synchronous motor with sintered neodymium-iron-boron magnets provides. These machines can take the form of PM-assisted synchronous reluctance machines, induction machines, switched reluctance machines, wound rotor synchronous machines (claw pole or biaxially excited), double-saliency machines with ac or dc stator current control, or brushless dc multiple-phase reluctance machines.