Physical Sciences and Mathematics Commons^™

Development And Construction Of A White Light Profiler For Industrial Applications, Martin Somers

Masters

With the ever decreasing tolerances in modern manufacturing processes it has become more important to define surface topography measurements quickly and accurately. Though contact methods, using the stylus probe, have been used for a long time more optical techniques are being brought into the market place. The advantages in using optical methods is obvious; no contact with the surface eliminates damage due to a probing tip and also the surface may be scanned in a matter of seconds. Optical techniques also have the advantage that a full field of view may be acquired, unlike point measurement where the surface must …

A Transaction Model To Improve Data Availability In Mobile Computing, Sanjay Kumar Madria, Bharat Bhargava

Computer Science Faculty Research & Creative Works

We incorporate a prewrite operation before a write operation in a mobile transaction to improve data availability. A prewrite operation does not update the state of a data object but only makes visible the future value that the data object will have after the final commit of the transaction. Once a transaction reads all the values and declares all the prewrites, it can pre-commit at mobile host (MH) (computer connected to unreliable mobile communication network). The remaining transaction's execution (writes on database) is shifted to the mobile service station (MSS) (computer connected to the reliable fixed network). Writes on database …

Tunable Local Polariton Modes In Semiconductors, Michael G. Foygel, Alexey Yamilov, Lev I. Deych, Alexander A. Lisyansky

Physics Faculty Research & Creative Works

We study the local states within the polariton band gap that arise due to deep defect centers with strong electron-phonon coupling. Electron transitions involving deep levels may result in alteration of local elastic constants. In this case, substantial reversible transformations of the impurity polariton density of states occur, which include the appearance/disappearance of the polariton impurity band, and its shift and/or the modification of its shape. These changes can be induced by thermo- and photoexcitation of the localized electron states or by trapping of injected charge carriers. We develop a simple model, which is applied to the O_p center …

Strong Enhancement Of Superconducting TC In Ferromagnetic Phases, Theodore R. Kirkpatrick, Dietrich Belitz, Thomas Vojta, Rajesh S. Narayanan

Physics Faculty Research & Creative Works

It is shown that the critical temperature for spin-triplet, p-wave superconductivity mediated by spin fluctuations is generically much higher in a Heisenberg ferromagnetic phase than in a paramagnetic one, due to the coupling of the magnons to the longitudinal magnetic susceptibility. Together with the tendency of the low-temperature ferromagnetic transition in very clean Heisenberg magnets to be of first order, this qualitatively explains the phase diagram recently observed in UGe₂.

Nature Of Charge Carriers In Disordered Molecular Solids: Are Polarons Compatible With Observations?, Paul Ernest Parris, Vasudev M. Kenkre, David H. Dunlap

Physics Faculty Research & Creative Works

Polaronic theories for charge transport in disordered organic solids, particularly molecularly doped polymers, have been plagued by issues of internal consistency related to the magnitude of physical parameters. We present a natural resolution of the problem by showing that, in the presence of correlated disorder, polaronic carriers with binding energies Δ ~ 50 - 500 meV and transfer integrals J ~ 1 - 20 meV are completely consistent with the magnitudes of field and temperature dependent mobilities observed.

Large-Scale Power Spectrum And Structures From The Enear Galaxy Peculiar Velocity Catalogue, S. Zaroubi, M. Bernardi, L. N. Da Costa, Y. Hoffman, M. V. Alonso, G. Wegner

Dartmouth Scholarship

We estimate the mass density fluctuations power spectrum (PS) on large scales by applying a maximum likelihood technique to the peculiar velocity data of the recently completed redshift—distance survey of early-type galaxies (hereafter ENEAR). Parametric cold dark matter (CDM)-like models for the PS are assumed, and the best-fitting parameters are determined by maximizing the probability of the model given the measured peculiar velocities of the galaxies, their distances and estimated errors. The method has been applied to CDM models with and without COBE normalization. The general results are in agreement with the high-amplitude power spectra found from similar analyses of …

Seeding Effect On Micro- And Domain Structure Of Sol–Gel-Derived Pzt Thin Films, A. L. Kholkin, Alexei Gruverman, A. Wu, M. Avdeev, P. M. Vilarinho, I. M. Miranda Salvado, J. L. Baptista

Alexei Gruverman Publications

Current trend to miniaturization requires precise control of micro- and domain structure of ferroelectric materials at the nanoscale level. This is essential for future applications of ferroelectric thin films in non-volatile memories, microactuators and pyroelectric arrays. In this work, the seeding effect on the nanoscale properties of ferroelectric Pb(Zr,Ti)O₃ (PZT) thin films is investigated using scanning force microscopy (SFM) capable of simultaneously resolving topographic and domain features on the surface of the films. It is shown that the addition of 5 mol% seeds (fine PZT powder) into the sol–gel precursor solution completely modifies the film’s microstructure leading to the …

The Prairie Naturalist Volume 33, No.3 September 2001

The Prairie Naturalist

SEASONAL REPRODUCTION IN SIGMODON HISPIDUS INHABITING TALLGRASS PRAIRIES OF OKLAHOMA ▪ J. A. Wilson and R. L. Lochmiller

USE OF THE INDEX OF BIOLOGICAL INTEGRITY IN EASTERN SOUTH DAKOtA RIVERS ▪ C. L. Milewski, C. R. Berry, and D. Dieterman

SEED USE BY VERTEBRATES AND INVERTEBRATES IN TALLGRASS PRAIRIE ▪ A. W. Reed, G. A. Kaufman, J. E. Boyer, Jr., and D. W. Kaufman

RANGE EXPANSION OF THE PILEATED WOODPECKER IN NORTH DAKOTA ▪ J. A. Dechant 163

LAB FATTENING AND NON-INVASIVE ESTIMATES OF BODY COMPOSITION IN DEER MICE ▪ E. T. Unangst, Jr., M. J. Blair, M. W. Granger, …

Off-Diagonal Exchange-Induced Transverse And Field-Induced Spin-Flop Order In The Diluted Metamagnet Fe0.85Mg0.15Br2, Wolfgang Kleeman, H. Aruga Katori, T. Kato, Christian Binek, K. Katsumata

Christian Binek Publications

Specific heat and Faraday rotation magnetometry were used to determine the axial magnetic phase diagram of the dilute hexagonal antiferromagnet Fe_0.85Mg_0.15Br₂. In contrast to metamagnetic pure FeBr₂, the first-order line of transverse phase transitions, H1(T), is disconnected with the antiferro-to-paramagnetic phase line H_c(T) and extends down to H_t=0 at T_t≈8.7 . This is attributed to symmetric off-diagonal exchange in the presence of structural disorder. Moreover, a spin-flop phase emerges beyond H_c(T) up to a bicritical point (T_b≈9.3 , μ_oH …

Measurement Of The W Boson Mass With The Collider Detector At Fermilab, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We present a measurement of the W boson mass using data collected with the CDF detector during the 1994–1995 collider run at the Fermilab Tevatron. A fit to the transverse mass spectrum of a sample of 30115 W→eν events recorded in an integrated luminosity of 84 pb^-1 gives a mass M_w=80.473±0.065(stat) ±0.092(syst) GeVc². A fit to the transverse mass spectrum of a sample of 14740 W→μν events from 80 pb^-1 gives a mass M_w=80.465±0.100(stat) ±0.103(syst) GeV/c². The dominant contributions to the systematic uncertainties are the …

The First Detection Of Coherent Emission From Radio Pulsars, F. A. Jenet, S. B. Anderson, T. A. Prince

Physics & Astronomy Faculty Publications

The statistical properties of the radio emission from the pulsars B0823+26, B0950+08, B1133+16, and B1937+21 are studied using high time resolution observations taken at the Arecibo Observatory in Puerto Rico. Temporally coherent non-Gaussian emission has been detected in three of the four observed objects. This is the first time such a phenomenon has been observed. The results have been interpreted using a generalized shot noise model, and various basic physical quantities pertaining to the magnetospheric plasma have been estimated.

Vide: A Visual Data Extraction Environment For The Web, Yi Li, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

With the rapid growth of information on the Web, a means to combat information overload is critical. In this paper, we present ViDE (Visual Data Extraction), an interactive web data extraction environment that supports efficient hierarchical data wrapping of multiple web pages. ViDE has two unique features that differentiate it from other extraction mechanisms. First, data extraction rules can be easily specified in a graphical user interface that is seamlessly integrated with a web browser. Second, ViDE introduces the concept of grouping which unites the extraction rules for a set of documents with the navigational patterns that exist among them. …

Nonparametric Techniques To Extract Fuzzy Rules For Breast Cancer Diagnosis Problem, Manish Sarkar, Tze-Yun Leong

Research Collection School Of Computing and Information Systems

This paper addresses breast cancer diagnosis problem as a pattern classification problem. Specifically, the problem is studied using Wisconsin-Madison breast cancer data set. Fuzzy rules are generated from the input-output relationship so that the diagnosis becomes easier and transparent for both patients and physicians. For each class, at least one training pattern is chosen as the prototype, provided (a) the maximum membership of the training pattern is in the given class, and (b) among all the training patterns, the neighborhood of this training pattern has the least fuzzy-rough uncertainty in the given class. Using the fuzzy-rough uncertainty, a cluster is …

The Structure And Stability Of Expanding And Converging Near-Stoichiometric Flames, Raymond Addabbo

Dissertations

The stability of expanding and converging premixed flames is investigated theoretically. These configurations are inherently unsteady and represent simple examples of positively (expanding) and negatively (converging) stretched flames. A new model is employed in this study that incorporates both hydrodynamic and diffusional-thermal effects. The model expands earlier works by incorporating variable transport properties, variations in the mixture strength and a more realistic dependence on viscosity.

The expanding flame is shown to remain stable at small radii provided the thermal diffusivity exceeds the mass diffusivity of the deficient reactant. However, once the flame achieves a critical size, a cellular instability appears, …

Asymptotic Methods In Applied Waveguide Problems, Helen Martynov

Dissertations

Some of the most challenging problems in acoustics and electromagnetics involve the study of scattered fields in waveguides caused by targets of elaborate shape. The complexity of the resulting scattered field depends on the geometry of the scatterer, and exact solutions exist only for the simple geometries.

The asymptotic methods developed in this dissertation give the approximate solutions for the scattered fields in two practically important geometries: an object placed inside a stratified waveguide, and a waveguide with multiple abrupt width transitions. The solutions for these geometries are obtained by approximating the field near the target or junction by the …

Structural, Transport And Magnetic Studies Of Perovskite Bi1-X Cax Mn O3, Hyungje Woo

Dissertations

This dissertation presents an investigation of the fundamental physics of the perovskite system Bi_1-xCa_xMn0₃. This material belongs to a group of simple perovskites called the manganites which are of technological importance for magnetic device applications as read-head sensors.

The Bi_1-xCa_xMnO₃ system is known to exhibit charge ordering (and high sensitivity to magnetic fields) for a much broader range of x than the well-characterized La_1-xCa_xMnO₃ system. However, the properties of Bi_1-xCa_xMnO₃ over the entire doping range are not well understood. …

Detection Of Vapor Phase Mercury Species By Laser Fluorescence Methods, Xiaomei Tong

Dissertations

Elemental and compound mercury are often both volatile and air stable. Several mercury species emissions have been identified in off-gases from industrial processes. The high toxicity of mercury species and the presence of mercury species in municipal waste and coal have prompted a demand for a cost-effective, accurate, and rugged technique for real-time, continuous detection of mercury species vapors. Real-time, continuous emission measurements are important for process control, monitoring, and remediation. At present, there is no commercial continuous emission monitoring (CEM) technique or instrumentation to reliably monitor volatile mercury species emissions from industrial stacks. Conventional measurement methods, such as cold …

Electrostatic Micro Actuators For Mirror And Other Applications, Xingtao Wu

Dissertations

Micro-electro-mechanical systems (MEMS) based electrostatic micro actuators are becoming important building blocks for innovations in optical signal processing and computing systems due to their inherently small size, high density, high speed and low power consumption. Generally, the principle of operation in these systems can be described as: an electrostatic attractive force causes a mechanical rotation, translation or deformation of a mirror plate, controlling the power, phase or direction of a light beam while it propagates through some medium or through free space. The fast paced, competitive research and development efforts widely being undertaken, both in academia and industry, are demanding …

Computationally Efficient Search For Large Primes, Wieslawa E. Amber

Theses

To satisfy the speed of communication and to meet the demand for the continuously larger prime numbers, the primality testing and prime numbers generating algorithms require continuous advancement. To find the most efficient algorithm, a need for a survey of methods arises. Concurrently, an urge for the analysis of algorithms' performances emanates. The critical criteria in the analysis of the prime numbers generation are the number of probes, number of generated primes, and an average time required in producing one prime. Hence, the purpose of this thesis is to indicate the best performing algorithm. The survey the methods, establishment of …

Design And Analysis For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides: Quarterly Report 5/15/01-8/15/01, Yitung Chen, Darrell Pepper, Randy Clarksean

Fuels Campaign (TRP)

No abstract provided.

Photon Decay At The Schwarzschild Horizon, Brett Altschul, R. Jackiw

Faculty Publications

A recent proposal that gravity theory is an emergent phenomenon also entails the possibility of photon decay near the Schwarzschild event horizon. We present a possible mechanism for such decay, which utilizes a dimensional reduction near the horizon. © 2001 Elsevier Science B.V.

Stimulated Emission Of Polarization-Entangled Photons, Antia Lamas-Linares, John C. Howell, Dik Bouwmeester

Mathematics, Physics, and Computer Science Faculty Articles and Research

Entangled photon pairs—discrete light quanta that exhibit non-classical correlations—play a crucial role in quantum information science (for example, in demonstrations of quantum non-locality^{1,2,3,4,5,6,7}, quantum teleportation^8,9 and quantum cryptography^10,11,12,31). At the macroscopic optical-field level non-classical correlations can also be important, as in the case of squeezed light¹³, entangled light beams^14,15 and teleportation of continuous quantum variables¹⁶. Here we use stimulated parametric down-conversion to study entangled states of light that bridge the gap between discrete and macroscopic optical quantum correlations. We demonstrate experimentally the onset of laser-like action for entangled photons, through …

Predators Of Mesoplatys Ochroptera In Sesbania Planted-Fallows In Eastern Zambia, G. Sileshi, M. Kenis, C. K.P.O. Ogol, S. Sithanantham

All Peer-Reviewed Publications

Mesoplatys ochroptera Stål (Coleoptera: Chrysomelidae) is a serious pest of the tropical legume sesbania (Sesbania sesban (L.) Merrill) widely used for soil fertility improvement in southern Africa. Surveys were conducted between October 1997 and June 1999 in order to identify the predators of M. ochroptera in sesbania fallows in eastern Zambia. The Heteroptera Afrius yolofa (Guérin-Méneville), Glypsus conspicuus (Westwood), Macrorhaphis acuta Dallas, Mecosoma mensor (Germar), Rhinocoris segmentarius (Germar), and Deraeocoris ostentans (Stål), the carabid beetle Cyaneodinodes fasciger (Chaudoir), the ants Tetramorium sericeiventre Emery and Pheidole sp., and the lacewing Mallada sp. were recorded as predators of M. ochroptera for the …

Designing A Terminal Area Bird Detection And Monitoring System Based On Asr-9 Data, Seth Troxel, Mark Isaminger, Beth Karl, Mark Weber, Arthur Levy

Bird Strike Committee-USA/Canada Joint Annual Meeting: 3rd (2001)

Conflicts between birds and commercial aircraft are a noteworthy problem at both large and small airports [Cleary, 1999]. The risk factor for United States airports continues to increase due to the steady rise in take-off/landings and bird populations. There is a significant bird strike problem in the terminal area as shown by the incidents reported in the National Bird Strike Database [Cleary and Dolbeer, 1999]. The focus of bird strike mitigation in the past has centered primarily on wildlife management techniques. Recently, an Avian Hazard Advisory System (AHAS) has been developed to reduce the risks of bird strikes to military …

Uneven Anodic Dissolution Of Iron Induced By Magnetic Field, Zhan-Peng Lv, De-Lun Huang, Wu Yang

Journal of Electrochemistry

The effects of magnetic field on anodic dissolution of iron in sulfuric acid were studied by potentiostatic polarization measurements and scanning electron microscopy observation. Magnetic field would reduce the surface film coverage fraction on electrode by enhancing the film dissolution process, thus made the electrode prone to active dissolution state. With increasing the applied potentials, magnetic field would accelerate the anodic dissolution, change the oscillation state or passive state to active dissolution state, or maintain the passive state, respectively. Potential for onset of passivation moved in the noble direction when magnetic field was imposed. At specific anodic potentials, denting occurred …

Simultaneous Determination Of Gold(Ⅲ) And Copper(Ⅱ) With Two-Way Stripping Voltammetry, Rong-Zong Hu, Dong-Ping Wei, Guang Wei, Yue-Ying Liu

Journal of Electrochemistry

A novel Two-way Stripping Voltammetry method for simultaneous determination of Au³⁺ and Cu²⁺ was reported in this paper. Because of the strongly electrostatic attraction of carbon paste electrode towards Au(Ⅲ) ion at positive potential and the biochemical contribution of Gram-positive bacteria strain DO1, the ion can be determined by cathodic stripping voltammetry. At the same time, Cu(Ⅱ) is reduced readily under the catalysis of ultra-fine gold particles, thereafter it can be determined by anode stripping voltammetry. There is no interference between the determination of Au³⁺ and Cu²⁺ . A perfect liner relationship between the concentrations of …

Current Oscillations In The System Of Carbon Steel/Phosphoric Acid/Platinum, Shao-Yuan Shi, Jin-Ping Wu, Jing Liu, An Lin

Journal of Electrochemistry

The periodic,aperiodic, chaotic and mixed-mode oscillations can occur in the process of the anodic electrodissolution of carbon steel in the solution of dilute phosphoric acid. More plentiful dynamic behaviors can be found in this system compared with the system of Fe/H₃PO₄/Pt.

A New Method For Impregnating Nafion Solution Into The Electrode Of Pemfc, Qian Tang, Ming Han, Bao-Lian Yi, Zhi-Yin Lin

Journal of Electrochemistry

We have developed a new method for impregnating Nafion solution into the catalyst layer of homemade hydrophobic electrode using capillary process. Those electrodes show better performance and higher utilization of catalyst (detected by CV and TEM) than traditional spray method in PEMFC. According to the results of SEM photograph and linear-analysis of sulfur and platinum for the electrode cross-section, we can conclude that the resin is uniform in the catalyst layer and has almost same depth as catalyst in the impregnated electrode. While in traditional method resin is not uniform in the catalyst layer and penetrates into the diffusion layer, …

Grb 010222: A Burst Within A Starburst, D. A. Frail, F. Bertoldi, G. H. Moriarty‐Schieven, E. Berger, P. A. Price, J. S. Bloom, R. Sari, S. R. Kulkarni, C. L. Gerardy, D. E. Reichart

Dartmouth Scholarship

We present millimeter and submillimeter wavelength observations and near-infrared K -band imaging toward the bright gamma-ray burst GRB 010222. Over seven epochs the flux density of the source was constant wit h an average flux density 3.74 ± 0.53 mJy at 350 GHz and 1.05 ± 0.22 mJy at 250 GHz, giving a spectral index α = 3 . 78 ± 0.25 (where F∝ ν^α). We rule out the possibility that this emission originated from the burst or its afterglow and we conclu de that it is due to a dusty, high redshift starburst galaxy (SMM J14522+43 01). …

Immobilization Of Long-Strand Dna Onto Gold Surface And Electrochemical Labeling Of Hybridization Of Dna, Jian-Zhang Zhou, Ling-Ling Wu, Li-Qin Dong, Zhong-Yu Lin, Jia-Wei Yan, Ping Dong, Yue Bao, Zhong-Hua Lin

Journal of Electrochemistry

Poly(diallyldimethylammonium chloride)(PDDA) was used to facilitate long strand DNA immobilization onto gold surface using self assembly method. Characterization of the PDDA self assembled film and subsequently immobilized DNA were carried out by Diffuse Reflectance Infrared, XPS, STM and electrochemical measurements. Hybridization of DNA was labeled by electrochemical method.