Physical Sciences and Mathematics Commons^™

Cyclic Deformation Behavior Of High-Purity Titanium Single Crystals: Part Ii. Microstructure And Mechanism, Xiaoli Tan, H. Guo, H. Gu, C. Laird, N. D. H. Monroe

Xiaoli Tan

Strain-controlled cyclic tests have been conducted on high-purity titanium single crystals with different orientations. The fatigue mechanisms of the titanium crystals were studied by means of a scanning electron microscope (SEM) and a transmission electron microscope (TEM). It was found that single slip lines, wavy slip lines, double slip lines, twins, and associated slip lines occurred in differently oriented single crystals. A new type of fractographic morphology, parallel traces, was observed. Dislocation patterns and cyclic twins, as well as the mechanical response, were analyzed. The dependence of the deformation mechanisms on the orientations of the single crystals is discussed.

Cyclic Deformation Behavior Of High-Purity Titanium Single Crystals: Part I. Orientation Dependence Of Stress-Strain Response, Xiaoli Tan, H. Gu, C. Laird, N. D. H. Monroe

Xiaoli Tan

Randomly oriented single crystals of high-purity titanium were prepared by strain annealing and were subjected to multiple-step fatigue testing under strain-controlled conditions, in order to determine their cyclic stress-strain curves (CSSCs). These were found to fall into three groups, depending on orientation and the extent of slip and twinning. For those crystals oriented for single prismatic slip, a plateau was observed in the CSSCs, persistent slip bands (PSBs) occurred, and the plateau stress was 38 MPa. In a second group, oriented for prismatic slip but for which cross-slip and twinning was favored, the plateau was suppressed and the flow stresses …

32. Ian Macmillan Ward, Otto Vogl

Otto Vogl

No abstract provided.

Murnaghan-Nakayama Rules For Characters Of Iwahori-Hecke Algebras Of The Complex Reflection Groups G(R,P,N), Thomas Halverson, A. Ram

Thomas M. Halverson

No abstract provided.

Abstract State Machines 1988-1998: Commented Asm Bibliography, James Huggins, Egon Borger

Computer Science Publications

Hartmut Ehrig asked the first author to write for this column what are the distinguishing features of the ASM approach to specification and verification of complex computing systems. In [21] an attempt had already been made to answer that question by discussing, in general comparative terms, some specific features which are characteristic for the ASM approach with respect to other well known approaches in the literature. That explanation seems to have been understood, as shown by the many positive reactions, but even more the numerous critical reactions of colleagues in the field who felt—rightly—that ASMs put justified doubt on cherished …

Bond Objects - A White Paper, Ladislau Bölöni

Department of Computer Science Technical Reports

No abstract provided.

Robust Scheduling Of Metaprograms, Ladislau Bölöni, Dan C. Marinescu

Department of Computer Science Technical Reports

No abstract provided.

In Situ Measurement Of Radiation Induced Conductivity In Oxide Insulators During Neutron Irradiation, D. P. White, L. L. Snead, S. J. Zinkle, W. S. Earthley

Physics Faculty Publications

No abstract provided.

The Approximate Functional Formula For The Theta Function And Diophantine Gauss Sums, Evangelos A. Coutsias, N.D. Kazarinoff

Branch Mathematics and Statistics Faculty and Staff Publications

By introducing the discrete curvature of the polygonal line, and by exploiting the similarity of segments of the line, for small w, to Cornu spirals (C-spirals), we prove the precise renormalization formula. This formula, which sharpens Hardy and Littlewood's approximate functional formula for the theta function, generalizes to irrationals, as a Diophantine inequality, the well-known sum formula of Gauss. The geometrical meaning of the relation between the two limits is that the first sum is taken to a point of inflection of the corresponding C-spirals. The second sum replaces whole C-spirals of the first by unit vectors times scale and …

From The Director: February 1998, Donald A. Wilhite

Drought Network News (1994-2001)

If it seems like considerable time has elapsed since you received the last issue of Drought Network News, it is not just your imagination. After much discussion, we decided not to publish the newsletter in October 1997. First, we had a limited number of submissions to include. Second, the task of editing the manuscript for a new drought book was an overwhelming task that was involving much of my time and that of my publications specialist, Deborah Wood. She is also responsible for Drought Network News. With more submissions and the near completion of the drought book, I …

A Mössbauer Spectral Study Of Nd₆Fe₁₃X, Where X Is Cu, Ag, And Au And Of The Spin Reorientation In Nd₆Fe₁₃Si, Dimitri Hautot, Gary J. Long, Fernande Grandjean, C. H. De Groot, K. H. Buschow

Chemistry Faculty Research & Creative Works

The Mössbauer spectra of Nd₆Fe₁₃X, where X is Si, Cu, Ag, and Au, have been measured between 80 and 500 K. A model corresponding to a basal alignment of the magnetic moments leads to excellent, internally consistent, fits for the Cu, Ag, and Au compounds. The resulting temperature dependences of the spectral hyperfine parameters are uniform and reveal for each Fe site the expected correlations between the isomer shift and the Wigner-Seitz cell volume and the hyperfine field and the number of Fe near neighbors. For Nd₆Fe₁₃Si, a different model must be …

Zebra Image Access System, Srilekha Mudumbai, Kshitij Shah, Amit P. Sheth, Krishnan Parasuraman, Clemens Bertram

Kno.e.sis Publications

The ZEBRA system, which is part of the VisualHarness platform for managing heterogeneous data, supports three types of access to distributed image repositories: keyword based, attribute based, and image content based. A user can assign different weights (relative importance) to each of the three types, and within the last type of access, to each of the image properties. The image based access component (IBAC) supports access based on computable image properties such as those based on spatial domain, frequency domain or statistical and structural analysis. However, it uses a novel black box approach of utilizing a Visual Information Retrieval (VIR) …

The Surface Plasmon Enhancement Effect On Adsorbed Molecules At Elevated Temperatures, P.T. Leung, Hai-Pang Chiang, W. S. Tse

Physics Faculty Publications and Presentations

The surface plasmon enhancement effect on adsorbed molecules at elevated substrate temperatures is studied theoretically using surface enhanced Raman scattering (SERS) as an example. The surface structure is idealized to be a monodisperse spherical particle with its nonlocal dielectric response accounted for. The temperature effects are modeled using a temperature-dependent collision frequency in the Drude model. Numerical results show that only a small decrease in the SERS enhancement ratio occurs for temperatures up to the melting point of the substrate, even for scattering close to the surface plasmon resonance frequency of the metal. More definitive results are subjected to more …

New Families Of Semi-Regular Relative Difference Sets, James A. Davis, Jonathan Jedwab, Miranda Mowbray

Department of Math & Statistics Faculty Publications

We give two constructions for semi-regular relative difference sets (RDSs) in groups whose order is not a prime power, where the order u of the forbidden subgroup is greater than 2. No such RDSs were previously known. We use examples from the first construction to produce semi-regular RDSs in groups whose order can contain more than two distinct prime factors. For u greater than 2 these are the first such RDSs, and for u = 2 we obtain new examples.

Some Harmonic N-Slit Mappings, Michael Dorff

Faculty Publications

The class SH consists of univalent, harmonic, and sense-preserving functions f in the unit disk, ∆, such that f = h+g where h(z) = (see PDF), g(z) = (see PDF) . SOH will denote the subclass with b1 = 0. We present a collection of n-slit mappings (n ≥ 2) and prove that the 2-slit mappings are in SH while for n ≥ 3 the mappings are in SOH. Finally we show that these mappings establish the sharpness of a previous theorem by Clunie and Sheil-Small while disproving a conjecture about the inner mapping radius.

Thermal Equilibrium Of Warm Clouds Of Charge With Small Aspect Ratio, Deborah L. Paulson, Ross L. Spencer

Faculty Publications

Global thermal equilibrium computations are presented for non-neutral plasmas whose radial size is much larger than their axial thickness. Axial and radial density profiles are computed for both ideal and nonideal Penning trap fields. Simple results are obtained in the limits of both low and high central density. Comparison is made to the grid calculations of Mason et al. [Phys. Plasmas 3 (5), 1502 (1996)].

Measurement Of The Total Cross Section For E+E-→Hadrons At √S=10.52 Gev, R. Ammar, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

Using the CLEO detector at the Cornell Electron Storage Ring, we have made a measurement of R≡ σ(e⁺e^- → hadrons)/σ(e⁺e^-→μ⁺μ^-)=3.56± 0.01± 0.07 at √s= 10.52 GeV. This implies a value for the strong coupling constant of α_s(10.52 GeV) =0.20±0.01±0.06, or α_s (M_Z)=0.13±0.005±0.03.

Environmental Management For Animal-Based Industries : Dairy Farm Effluent, Western Australia Agriculture Western Australia Bunbury Regional Office., Dairy Industry Nutrient Strategy Working Group (W.A.)

Bulletins 4000 -

The effluent which collects around dairies and their associated feeding facilities should be regarded as a resource to be retained and used on the farm, rather than a waste product for disposal.

These guidelines aim to assist dairy farmers plan effluent management systems which are practical, as well as easy to install and manage, while also being acceptable to the agencies and authorities given the responsibility of protecting the environment. .

An Investigation Of The Presence Of Pesticides In The Drinking Water Of Greater Cairo, Mohsen Majed Alami

Archived Theses and Dissertations

No abstract provided.

Specific Heat And Critical Fields Of The Organic Superconductor Β″–(Bedt-Ttf)2sf5ch2cf2so3, S. Wanka, J. Hagel, D. Beckmanm, J. Wosnitza, J. A. Schlueter, Jack M. Williams, P. G. Nixon, Rolf Walter Winter, Gary L. Gard

Chemistry Faculty Publications and Presentations

We report on specific-heat, magnetization, and ac-susceptibility measurements of β″–(BEDT-TTF)₂SF₅CH₂CF₂SO₃, an organic superconductor with Tc=4.5 K, where BEDT-TTF stands for bis(ethylenedithio)-tetrathiafulvalene. The jump of the specific heat C at Tc and the exact form of the specific heat difference between C in the superconducting (B=0 T) and in the normal (B=3.5 T) state can be well described by BCS theory with strong coupling. We estimate an electron-phonon coupling parameter λ≈1.1. From measurements of C in magnetic fields we extract the upper critical field Bc₂(T). Low-field dc-magnetization measurements were used to determine the temperature dependence of the lower critical field Bc₁. …

Four-Jet Final State Production In E+E- Collisions At Centre-Of-Mass Energies Ranging From 130 To 184 Gev, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

The four jet topology is analysed in the ALEPH data taken between November 1995 and October 1997, at centre-of-mass energies ranging from 130 to 184 GeV. While an unexpected accumulation of events with a dijet mass sum around 105 GeV/c 2 had been observed during the first run in 1995 at 130/136 GeV, corresponding to an integrated luminosity of 5.7 pb1 , no significant dierences between data and standard model prediction is seen, either in the high energy runs (81.1 pb1 taken at centre-of-mass energies from 161 to 184 GeV) or in the 7.1 pb1 recorded during a new short …

Optimum Preventive Maintenance Policies For The Amraam Missile, Scott J. Ruflin

Theses and Dissertations

The overall objective of this research effort was to formulate a preventive maintenance strategy for AMRAAM missiles subject to extended captive carry flight time. A preventive maintenance policy is only applicable if the item in question is aging, or deteriorating with time. Therefore, a supporting objective of this research is to characterize the aging process of the missile system through a non-parametric analysis of its Mean Residual Life (MRL) function. Three non-parametric, censored-data MRL function estimation techniques discussed in the literature are examined via a numerical example. All three estimation techniques provide MRL functions that exhibit greatly exaggerated decreasing trends …

Chemical And Electrochemical Studies Of Cl2Fes2Ms2Fecl2N- Clusters [M = Mo (N = 2), W (N = 2), V (N = 3)], Yanming Liu, Jinhai Chen, Michael D. Ryan

Chemistry Faculty Research and Publications

The electrochemistry and spectroelectrochemistry of [Cl₂FeS₂MS₂FeCl₂]^n- clusters (where n = 2 for M = Mo and W and n = 3 for M = V; Ia, Ib, and Ic, respectively) and the dimetal complex [Cl₂FeS₂MoS₂]^2- (IIIa) were examined in order to characterize the structures and properties of the one-electron-reduced complexes. A stable reduction product for Ia was observed spectroelectrochemically at −1.05 V, which could be oxidized back to the starting complex. Reduction at more negative potentials caused …

A Signcryption Scheme With Signature Directly Verifiable By Public Key, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

Signcryption, first proposed by Zheng, is a cryptographic primitive which combines both the functions of digital signature and public key encryption in a logical single step, and with a computational cost significantly lower than that needed by the traditional signature-then-encryption approach. In Zheng's scheme, the signature verification can be done either by the recipient directly (using his private key) or by engaging a zero-knowledge interative protocol with a third party, without disclosing recipient's private key. In this note, we modify Zheng's scheme so that the recipient's private key is no longer needed in signature verification. The computational cost of the …

A Photometric And Spectroscopic Study Of The Cataclysmic Variable Sx Leonis Minoris In Quiescence And Superoutburst, R. Mark Wagner, John R. Thorstensen, R. K. Honeycutt, S. B. Howell

Dartmouth Scholarship

We present CCD imaging, CCD photometry on long and short timescales, and time-resolved spectroscopy of SX LMi, a new SU Ursae Majoris type dwarf nova. The quiescent optical spectrum shows broad double-peaked Balmer, He I, and He II emission lines, similar to other quiescent dwarf novae. Absorption lines from a late-type secondary are not detected. Time-resolved spectra obtained in quiescence reveal radial velocity variations of the Balmer emission lines on a period of 0.06717 ± 0.00011 days, or 96.72 ± 0.16 minutes, with only a slight possibility of a daily cycle-count error. Optical photometry obtained between 1987 and 1991 shows …

Kempe Revisited, Joan Hutchinson, Stan Wagon

Stan Wagon, Retired

No abstract provided.

Trade In Medicinal Plants: The Need For It To Be Carried Out Based On The Principle Of Conservation, Nat Quansah

Nat Quansah

No abstract provided.

Density Fluctuations In Vibrated Granular Materials , E.R. Nowak, J.B. Knight, E. Ben-Naim, H.M Jaeger, S.R. Nagel

Eli Ben-Naim

We report systematic measurements of the density of a vibrated granular material as a function of time. Monodisperse spherical beads were confined to a cylindrical container and shaken vertically. Under vibrations, the density of the pile slowly reaches a final steady-state value about which the density fluctuates. We have investigated the frequency dependence and amplitude of these fluctuations as a function of vibration intensity Γ. The spectrum of density fluctuations around the steady state value provides a probe of the internal relaxation dynamics of the system and a link to recent thermodynamic theories for the settling of granular material. In …

Inference Of Steady Stellar Wind V(R) Laws From Optically Thin Emission Lines Ii. Occultation Effects And The Determination Of Intrinsic Stellar Properties., R. Ignace, J. C. Brown, L. L. Richardson, J. P. Cassinelli

Richard Ignace

This paper extends previous work on the inversion of line profiles to obtain wind velocity laws to a case that includes the occultation of light from the far side of the star. The velocity law v(r) is assumed to be from a wind that is steady and spherically symmetric. The wind is also assumed to be optically thin in the emission line profile. The major result here is the derivation of an analytic inversion formula. The effects of stellar occultation are shown to produce a significant change in the analysis from paper I, and by accounting for the occultation, the …

Biodegradation Of Pah Contaminated Soil And Sludge Using Non-Ionic Surfactants, Seema Narula

Dissertations

Polycyclic aromatic hydrocarbons (PAHs) are one of the most prevalent environmental pollutants contaminating a large number of industrial and Superfund sites. Low solubility and sorption to solid surfaces limit biodegradation rates of PAHs in the environment. Bioremediation of these compounds have been previously tested with partial success. In the present study, aerobic biodegradation of three PAHs (fluorene, phenanthrene, and pyrene) has been studied in shaker flasks, batch fermenter, and bioslurry reactor, in the presence of non-ionic surfactants. A mixed bacterial culture derived from both a refinery sludge and an activated sludge was used as the seed population in the degradation …