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Displaying 1226 - 1250 of 1721

Weibull Strength Scaling for Standardized Rectangular Flexure Specimens

January 1, 2003
Author(s)
George D. Quinn
Formulas for the effective volumes and effective surfaces for rectangular bars loaded in flexure are reviewed. The ratio of strengths from any two configurations, such as 3-point flexural to 4-point, is independent of whether the flaws are volume or

Direct Separation of Short Range Order in Intermixed Nanocrystalline and Amorphous Phases

December 1, 2002
Author(s)
Charles E. Bouldin, A I. Frenkel, A V. Kolobov, I K. Robinson, J O. Cross, Y Maeda
Diffraction Anomalous Fine Structure (DAFS) and Extended X-Ray Absorption Fine Structure (EXAFS) measurements have been combined to determine short-range order (SRO) about a single atomic type in a sample of mixed amorphous and nanocrystalline phases

Microstructure-Based Simulation of Thermomechanical Behavior of Composite Materials by Object-Oriented Finite Element Analysis

December 1, 2002
Author(s)
N Chawla, B V. Patel, M Koopman, K K. Chawla, R Saha, B R. Patterson, Lin-Sien H. Lum, Stephen A. Langer
While it is well recognized that microstructure controls the physical and mechanical properties of a material, the complexity of the microstructure often makes it difficult to simulate by analytical or numerical techniques. In this paper we present a

Multiple Small-Angle Neutron Scattering Studies of Anisoptropic Materials

December 1, 2002
Author(s)
Andrew J. Allen, Norman F. Berk, J Ilavsky, Gabrielle G. Long
Various authors have recognized the power of multiple small-angle neutron scattering (MSANS) analysis in providing information on coarse, concentrated microstructures involving micrometer length-scales larger than are accessible in conventional small-angle

Analysis of the Isoelectric Point in Moderately Concentrated Alumina Suspensions Using Electroacoustic and Streaming Potential Methods

November 1, 2002
Author(s)
Vincent A. Hackley, J Patton, Lin-Sien H. Lum, R Wasche, H Abe, M Naito, Y Hotta, H Pendse
Alumina suspended in aqueous electrolytic solution was used as a model ceramic suspension to investigate the measurement precision and influencing factors for the determination of the isoelectric point (IEP) in moderately concentrated systems. Techniques

Application of Self-Assembled Technology to Probe Fiber Matrix-Adhesion

October 1, 2002
Author(s)
E Feresenbet, D T. Raghavan, Gale A. Holmes
Adhesion at the fiber-matrix interface of composite is often related to a combination of factors such as mechanical interlocking, physico-chemical interactions, and chemical bonding of the fiber-matrix interphase region. We demonstrate the use of (self

Dynamic Analysis of Sliding Contacts at Head-Disk Interface

October 1, 2002
Author(s)
Tze J. Chuang, Stephen M. Hsu
As magnetic data storage technology moves towards higher areal data density with higher rotational speeds and lower flying heights, the propensity of severe sliding contacts at the head-disk interface is bound to increase. The tribological performance of

Nanopowder Characterization: Challenges and Future Directions

October 1, 2002
Author(s)
Ajitkumar Jillavenkatesa, J F. Kelly
This manuscript summarizes the proceedings and conclusions of a workshop organized to address issues associated with particle size and size distribution characterization of nanaopowders. Presentations made during this workshop highlighted the strengths and

Semifluorinated Aromatic Side-Group Polystyrene-Based Block Copolymers: Bulk Structure and Surface Orientation Studies

October 1, 2002
Author(s)
X Li, L Andruzzi, E Chiellini, Giancarlo Galli, Christopher K. Ober, A Hexemer, E K. Kramer, Daniel A. Fischer
Two families of narrow polydispersity poly(styrene)-based block copolymers bearing side groups containing both a phenyl ring and a para-linked semifluorinated side group were designed to produce stable low energy surfaces. The effects of the phenyl ring on

Structural Study of an Unusual Cubic Pyrochlore Bi 1.5 Zn o.92 Nb 1.5 O 6.92

October 1, 2002
Author(s)
Igor Levin, T G. Amos, J Nino, Terrell A. Vanderah, C A. Randall, M T. Lanagan
Single-phase pyrochlore specimens of Bi 1.5Zn 0.92Nb 1.5O 6.92 were studied using combined electron, X-ray and neutron powder diffraction techniques. Rietveld refinements using neutron powder diffraction data confirmed an average pyrochlore structure A 2B

Crystal Structures and Reference Diffraction Patterns of BaSrR 4 O 8

September 1, 2002
Author(s)
Winnie K. Wong-Ng, James A. Kaduk, J Dillingham
The structure of BaSrR4O8 (where R = La, Nd, Sm, Gd, Eu, Dy, Ho, Y, Er, Tm, Yb, and Lu) has been investigated, and the X-ray reference patterns of these compounds have been prepared using the Rietveld refinement technique. BaSrR2O4 are isostructural to

Finite Element Simulation of Straight Plunge Grinding for Advanced Ceramics

September 1, 2002
Author(s)
Tze J. Chuang, S Jahanmir, Hai C. Tang
The objective of this work is to model the grinding forces and the associated stress and deformation fields generated in a ceramic workpiece during surface plunge grinding. A two-dimensional finite element model is constructed with the grinding parameters

Polarized Ultraviolet Raman Spectroscopy of B-Si 3 N 4

September 1, 2002
Author(s)
R Vogelgesang, M Grimsditch, Jay S. Wallace
We have studied single crystals of Β-Si 3N 4 with polarization-resolved Raman spectroscopy in order to unambiguously obtain the symmetry character of zone center optical phonon modes. By applying ultraviolet excitation radiation, approaching resonance

First Principles Studies of KnbO 3 , KtaO 3 and LiTaO 3 Solid Solutions

August 1, 2002
Author(s)
S A. Prosandeev, Eric J. Cockayne, Benjamin P. Burton
KTaO3-based solid solutions exhibit a variety of interesting physical phenomena. To better understand these phenomena, we performed first-principles calculations on [K1-x,Lix]TaO3 (KLT) and K[Ta1-xNbx]O3 (KTN) supercells. Our results show Li displacements
Displaying 1226 - 1250 of 1721