Digital Commons Network^™

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 …

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 …

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 …

The Catalyst, February 1998, Illinois State University, Center For The Advancement Of Teaching

The CATalyst

Newsletter of the Center for the Advancement of Teaching (CAT) at Illinois State University

Gender-Based Pay Gaps: Methodological And Policy Issues In University Salary Studies, Myra Marx Ferree, Julia Mcquillan

Department of Sociology: Faculty Publications

Methodology is often a point of contention in gender-based salary studies. Although this debate seems at first to be merely about technical issues, it also has an important conceptual dimension. We argue that there are two competing implicit conceptions of discrimination, one institutional and the other individual, that underlie many such debates. We first contrast the preferred methodologies advanced by each side, the policy capturing approach and the flagging approach, and explore the theoretical meaning of their statistical models. We then describe a practical application of both methodological approaches in one specific salary inequity study. In conclusion, we reflect on …

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.

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. …

Pulmonary Disposition Of Lipophilic Amine Compounds In The Isolated Perfused Rabbit Lung, Said H. Audi, Christopher A. Dawson, John H. Linehan, Gary S. Krenz, S. B. Ahlf, David L. Roerig

Biomedical Engineering Faculty Research and Publications

We measured the pulmonary venous concentration vs. time curves for [³H]alfentanil, [¹⁴C]lidocaine, and [³H]codeine after the bolus injection of each of these lipophilic amine compounds (LAC) and a vascular-reference indicator (fluorescein isothiocyanate-dextran) into the pulmonary artery of isolated perfused rabbit lungs. A range of flows and perfusate albumin concentrations was studied. To evaluate the information content of the data, we developed a kinetic model describing the pulmonary disposition of these LAC that was based on indicator dilution theory, and we sought a robust approach for interpreting the estimated model parameters. We found that the …

A Visual Object-Relationship Query Language For User-Database Interaction, Keng Siau

Research Collection School Of Computing and Information Systems

User–database interaction has a direct and immediate effect on the effectiveness and efficiency of database end users. Traditional query languages like SQL and QBE require end users to understand the underlying data structure in the database. This is a burden on end users, especially novice end users who have little technical knowledge or understanding of database. To alleviate the need for end users to know the logical database organization, this paper proposes the use of an object–relationship (OR) model and a formal high-level visual query language as the interface. Using this interface, end users communicate only domain knowledge with the …

Issue No. 46: February 1998, Historical Society Of New Mexico

La Crónica de Nuevo México

1 Arizona/New Mexico Joint Conference in Santa Fe, April 2-5, 1998, for Arizona Historical Society and the Historical Society of New Mexico
1 The Annual Book & Artifact Auction
1 Hilton Hotel Reservations
2 A Canticle for Fray Angélico
5 Book Reviews, Heart of the Circle: Photographs by Edward S. Curtis of Native American Women
5 Book Reviews, Tales of Los Alamos: Life on the Mesa, 1943-1945
5 Book Reviews, Wide Ruins: Memories from a Navajo Trading Post
5 Book Reviews, The Chile Chronicles: Tales of a New Mexico Harvest
6 Land of Light: Photographs of Ghost Ranch, an …

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)].

The Register, 1998-01-31, North Carolina Agricutural And Technical State University

NCAT Student Newspapers

No abstract provided.

Orthogonal Transmultiplexers : Extensions To Digital Subscriber Line (Dsl) Communications, Xueming Lin

Dissertations

An orthogonal transmultiplexer which unifies multirate filter bank theory and communications theory is investigated in this dissertation. Various extensions of the orthogonal transmultiplexer techniques have been made for digital subscriber line communication applications.

It is shown that the theoretical performance bounds of single carrier modulation based transceivers and multicarrier modulation based transceivers are the same under the same operational conditions. Single carrier based transceiver systems such as Quadrature Amplitude Modulation (QAM) and Carrierless Amplitude and Phase (CAP) modulation scheme, multicarrier based transceiver systems such as Orthogonal Frequency Division Multiplexing (OFDM) or Discrete Multi Tone (DMT) and Discrete Subband (Wavelet) Multicarrier …

A Model For Travel Mode Switching, Lei Cao

Dissertations

Transportation policy research assesses the effect of policy changes such as the imposition of a parking charge or the augmentation of passenger rail service, on individual travel behavior. Over the last few decades, Conditional Lo it Model has been strongly advocated among discrete choice models for transportation policy study due to its ease of estimation and realistic outcomes.

This dissertation analyzes the necessity of the entry of constraints in the indirect utility function. These functions are used in discrete choice models and form the basis for travel demand modeling. This dissertation proposes a hypothesis that the explicit entry of constraints …

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 …

Flag : The Fault-Line Analytic Graph And Fingerprint Classification, Ching-Yu Huang

Dissertations

Fingerprints can be classified into millions of groups by quantitative measurements of their new representations - Fault-Line Analytic Graphs (FLAG), which describe the relationship between ridge flows and singular points. This new model is highly mathematical, therefore, human interpretation can be reduced to a minimum and the time of identification can be significantly reduced.

There are some well known features on fingerprints such as singular points, cores and deltas, which are global features which characterize the fingerprint pattern class, and minutiae which are the local features which characterize an individual fingerprint image. Singular points are more important than minutiae when …

Decentralized Reliable Control For Large-Scale Lti Systems, Zhengfang Chen

Dissertations

Reliable control concerns the ability of closed loop system to maintain stability and regulation properties during arbitrary sensor, controller, and actuator failure. Reliable control research has been an active research topic for more than 10 years.

Recent approach for reliable control includes the H∞ method, the algebraic factorization design, and the robust servomechanism control. These methods have been surveyed and discussed in this thesis with the robust servomechanism control methodology serving as the basis of the research development of this work.

In this thesis, the reliable control for large-scale, multi-input/output linear system is considered. Two concepts of reliable control …

Numerical Study Of Three-Dimensional Free Convection From Semi-Enclosed Geometry And Discontinuous Heat Sources, Aklilu T.G. Giorges

Dissertations

Three-dimensional natural convection from three-by-three array of isoflux heat sources mounted on one vertical wall of semi-enclosed region has been numerically investigated. Detailed thermal information of this important engineering configuration is currently not available. The major objective of this study was to obtain this needed thermal and velocity information.

The semi-enclosed geometry can be viewed as a thin rectangular region with four closed and two open sides. The open surfaces are located at the top and adjacent side. For the fluid air, Pr = 0.71, the study covered a heat flux based Rayleigh number (Ra) range of (10² ≤ …

Effects Of Surfactants And Fenton's Reagents On Extraction And Destruction Of Phenanthrene In Spiked Sand, Ming-Chin Chang

Dissertations

In this study, surfactants and Fenton's reagents (Fe(II) and H₂0₂) ere proposed to solve contaminated site problems in situ on a lab scale. Phenanthrene is a simple PAHs (polynuclear aromatic hydrocarbons). The phenanthrene spiked ottawa sand simulated contaminated soil. HPLC was used for phenanthrene analysis because it provided excellent separation and no interference. Six surfactants (including nonionic and ionic) were tested. The operating conditions were optimized based on process and economic considerations such as reaction time, mixing speed, concentrations of surfactants and concentrations of Fenton's reagents. Surfactants could effectively dissolve phenanthrene from the spiked sand. In …

Thermodynamic Properties Of Chlorocarbons And Kinetic Analysis For A- And B -Addition Of Oh+C2h3cl, Li Zhu

Theses

Thermodynamic properties, ΔHf°₂₉₈, S°₂₉₈ and Cp(T) 300≤T/K≤1500, for C₁, C₂ chlorocarbons are calculated by AM1 and PM3 in MOPAC6, then compared with the literature data. AM1- and PM3-derived S°298 and Cp(T) (300≤T/K≤1500) are found to be consistent with the literature (Rd ≤ ± 5%). ΔHf°₂₉₈ of CH₂Cl₂, CH₂ClCH₂Cl, CH₂ClCHCl₂, CHCl₂CHCl₂, and C₂Cl₄ and C₂Cl₂ calculated by PM3 as well as ΔHf°₂₉₈ of CCl₄, C₂HCl₃, …

Dynamic Friction Measurement, Modeling, And Compensation For Precise Motion Control, Simon Cohn

Theses

In this thesis, measurements of dynamic friction in a hydrodynamic journal bearing were performed for varying sinusoidal velocity excitations, loads, and lubricants. The results indicate that the friction data displays a negative slope in the mixed region of friction vs. velocity (f-v) curves, and also shows that the dynamic friction is not just a function of current velocity, but also a function of velocity history (hysteresis). These results are in agreement with previous experimental investigations by other investigators in lubricated friction.

Secondly, a dynamic friction model is fully explored and partially extended to provide quantitative agreement to measured friction values. …

Investigation Of Optical Properties Of Inp, Ain And Sapphire For Applications In Non-Contact Semiconductor Process Monitoring, Rajasekhar Velagapudi

Theses

The objective of this thesis was to develop a reliable multi-wavelength pyrometer for simultaneous measurement of the wafer temperature and its optical properties in the wavelength range of 1 to 20 microns and temperature range of 30 to 1500° C. The spectral emissometer has been utilized for measurement of the temperature dependent optical properties of InP, AlN and Sapphire. The experimental results presented in this thesis showed that the measurement of high temperature optical properties could be performed reliably with a novel approach using the spectral ernissometer. The temperature determination capability of the emissometer was tested and verified using a …

Kinematic Analysis Of A Swash-Plate Mechanism Using Transformation Matrices, David Edgar Evans

Theses

The swash-plate mechanism is used to transfer rotational motion into translational motion and vice versa. Using transformation matrices to describe each joint, the displacements of the swash-plate mechanism were analyzed. The general transformation matrix model for the plane joint, not previously developed using transformation matrices, was presented. The solution was tested using a computer program. Examples of three different swash-plate angles; 10, 45, and 25' were considered. The solution was found to agree with previous solutions while offering a more complete description of the mechanism. Future work in this area could include a complete static, velocity, and/or dynamic analysis of …

Introduction To Pollution Prevention Concepts In Freshman Chemistry Through Simulations And Hypermidia, Aniraban Bhaumik

Theses

As citizens of the 20th century, a key issue we all are aware of is degradation of the environment. In the interest of teaching the environmental issues to freshmen engineers, this study develops a computer aided learning/teaching (CAL/T) tool.

This CAL/T tool consists of Internet based multimedia courseware and intelligent simulations. The courseware assembles the fundamentals of chemistry associated with current environmental issues such as air pollution, stratospheric ozone layer depletion and environmentally sensitive or 'clean' manufacturing. The courseware targets early and comprehensive understanding of pollution prevention concepts with a focus on environmentally friendly manufacturing. The courseware includes: on-line text, …

Optimal Synthesis Of A Planar Four-Bar Function Generator Based On Imderect Measure Of Structural Error, Robert Ellis

Theses

A novel technique for optimal synthesis of a planar four-bar function generator is presented. An indirect measure of structural error is used to formulate an objective function which, along with its derivatives, is straightforward to evaluate and results in an elegant and robust algorithm. Lagrange multipliers are used to incorporate the loop closure constraint into the objective function.

In this thesis, the formulation of the objective function and the minimization algorithm are described, examples are presented, and the virtues and shortcomings of the algorithm are discussed.

Performance Enhancement Of Linear Robotic Workcell Using Dsp Based Control, Kedar Arvind Godbole

Theses

Robotic Controllers have for the major part been computer implementations of PID or similar controllers. In this thesis DSP based control of a Robotic Workcell is presented. The control algorithms used with the DSP based controller are Input Shaping and also State Feedback. Input Shaping is a Feed Forward strategy for eliminating vibration under certain conditions. In this thesis Input Shaping is applied to the performance enhancement of a linear robot system. Although feedback control strategies offer higher accuracy and are much more robust, feedforward strategies offer possibilities for improving the response time. Input Shaping is successfully applied to the …

A Design-For Retirement Rating Model For Environmentally Conscious Products, Xin He

Theses

Design-For-Retirement is a concept that allows one to design a product such that its retirement time and post-life treatment are optimized to lead to the minimum environmental impact and maximum financial gain. Retired product parts or subassemblies face three primary multi-lifecycle engineering treatments. The first one is to recondition them for reuse in the next lifecycle. The second one is to convert their post life parts into a material form for recycling back into new parts. The last is to dump or landfill them. Each option has a significantly different environmental cost-benefit ratio. Another important concern is the dismantling process …

Development And Characteristics Of Carbon Nitride Thin Solid Films For Advanced Coating Applications, Muhammad A. Hussain

Theses

Carbon nitride films were synthesized on silicon substrate by reactive magnetron sputtering of graphite target in an environment of Ar and nitrogen gas. The performance of a negative carbon ion source was also investigated to use the source in negative ion-beam-assisted deposition. These films were synthesized at room temperature at a constant pressure of 5 mtorr and at 300 Watts R.17 power, but at different composition of nitrogen in Ar-N₂ gas mixture ranging from 0-53 percent. The films deposited were microscopically smooth, amorphous and their properties found to be varied with nitrogen composition in plasma. The deposition rate was …

Applications Of Internet Technology For Requirements Elicitation, Deepak Pandit

Theses

During the Requirements Elicitation part of a project various stakeholders need to be able to communicate their requirements to the developers, and the developers need to be able communicate their understanding back to the stakeholders. Communication between the various members of the project is the key factor during the Requirements Elicitation part of a project. Easing communications between stakeholders and developers makes the process of eliciting requirement easier, leading to better requirements specification and eventually a better product.

The Requirements Elicitation Process through Internet (REPI) web site has been designed and implemented to explore this idea. The prototype version of …