Physical Sciences and Mathematics Commons^™

Computer Science: A Guide To Selected Resources On The Internet., Michael Knee

University Libraries Faculty Scholarship

No abstract provided.

Fish Protection Measures To Ensure Fish For The Future, Jo Bunting

Fisheries management papers

The protection of Western Australia's aquatic animals, plants and habitats is important for many reasons. Fish, and many aquatic invertebrates, have significant commercial, recreational and social importance. Aquatic habitats provide food, refuge and breeding areas for fish and other animals. In addition, some habitats, such as rocky reefs and seagrass meadows, act as nursery sites for juvenile animals. Some habitats and their inhabitants (such as coral reefs) also have aesthetic values which support economically and socially important industries, such as tourism.

Scott Coastal Plain A Strategy For A Sustainable Future, Department Of Agriculture And Food, Western Australia

Bulletins 4000 -

The Scott Coastal Plain has significant attributes that make it an area of State and regional significance for agricultural production. The climate, availability of good quality groundwater for irrigation, and large lot sizes provide opportunities for mechanised horticultural production which other parts of the State may not have.

An estimate of the area that could be used for each agricultural land use has been developed, at a broad study area level. The figures presented in this report show that diversified production combining tree plantation and/or irrigation (cropping or hay/silage) with grazing enterprises provides for potential increases in gross margins and …

Reflectance Spectral Features And Detection Of Superficial Scald–Induced Browning In Storing Apple Fruit, Olga B. Chivkunova, Alexei E. Solovchenko, S. G. Sokolova, Mark N. Merzlyak, I. V. Reshetnikova, Anatoly A. Gitelson

School of Natural Resources: Faculty Publications

Reflectance (R) spectra of Antonovka apples in the visible and near infrared ranges of the spectrum were studied during fruit storage. Specific spectral features of reflectance of healthy ripening fruits and those arising as a result of superficial scald development and browning induced artificially by n–hexane treatment were revealed and compared. Both superficial scald and n–hexane treatment brought about a strong decrease of reflectance, especially, in the green near 550 nm. During natural fruit ripening in the absence of superficial scald development, a high correlation was found between reflectances at 550 and 700 nm. In contrast, as a …

Cooperative Magnetism And The Preisach Model, Ralph Skomski, David J. Sellmyer

David Sellmyer Publications

Cooperative and noncooperative magnetization processes in magnetic nanostructures are investigated. Using model calculations it is shown that the Preisach model and related approaches, such as Henkel, ΔM, and ΔH plots, describe magnetism on a mean-field level and cannot account for intra- and inter-granular cooperative effects. For example, the ΔM plot of a nucleation-controlled two-domain particle gives the false impression of a positive intergranular interaction. A simple but nontrivial cooperative model, consisting of two interacting but nonequivalent particles, is used to show that cooperative effects are most pronounced for narrow switching-field distributions, i.e., for nearly rectangular loops. …

Ultraviolet Lasing In Cholesteric Liquid Crystals, A. F., Peter Palffy-Muhoray, B. Taheri

Peter Palffy-Muhoray

We report the observation of stimulated emission and mirrorless lasing in pure cholesteric liquid crystals. The lasing action is attributed to the combination of the fluorescence and the distributed feedback that are due to the inherent periodic structure of the liquid crystal. If the reflection band matches the intrinsic emission of the cholesteric liquid crystal, the crystal becomes a natural laser material, which will self-lase, without any optical elements or the addition of dyes, under picosecond excitation at 355 nm. Samples have been made to lase at different wavelengths in the near UV by shifting of the edge of the …

A Solid State 13c Nmr Study Of Kerogen Degradation During Black Shale Weathering, Steven T. Petsch, R. J. Smernik, T. I. Eglinton, J. M. Oades

Steven T. Petsch

Solid state 13C nuclear magnetic resonance (NMR) spectroscopy is used to examine kerogen composition in weathering profiles of the Monterey, Green River, Woodford, and New Albany formations. Techniques include cross polarization (CP) and Bloch decay (BD) spectral acquisition, dipolar dephasing (DD), spin counting, experiments to provide estimates of relaxation times (T1ρH and T1H), and proton spin relaxation editing (PSRE). It is demonstrated that CP/MAS (cross polarization/magic angle spinning) spectra obtained on isolated kerogens provide reliable characterization of kerogen composition (compared with BD spectra and whole-rock samples). Highly aliphatic (polymethylenic) kerogens are not appreciably altered during weathering. Aromatic and/or branched aliphatic …

Inhibition Of The Aminopeptidase From Aeromonas Proteolytica By L-Leucinephosphonic Acid. Spectroscopic And Crystallographic Characterization Of The Transition State Of Peptide Hydrolysis, Carin Stamper, Brian Bennett, Tanya Edwards, Richard C. Holz, Dagmar Ringe, Gregory A. Petsko

Physics Faculty Research and Publications

The nature of the interaction of the transition-state analogue inhibitor l-leucinephosphonic acid (LPA) with the leucine aminopeptidase from Aeromonas proteolytica (AAP) was investigated. LPA was shown to be a competitive inhibitor at pH 8.0 with a K_i of 6.6 μM. Electronic absorption spectra, recorded at pH 7.5 of [CoCo(AAP)], [CoZn(AAP)], and [ZnCo(AAP)] upon addition of LPA suggest that LPA interacts with both metal ions in the dinuclear active site. EPR studies on the Co(II)-substituted forms of AAP revealed that the environments of the Co(II) ions in both [CoZn(AAP)] and [ZnCo(AAP)] become highly asymmetric and constrained upon the addition of …

Ozone And Tracer Transport Variations In The Summer Northern Hemisphere Stratosphere, E. C. Cordero, S. R. Kawa

Faculty Publications, Meteorology and Climate Science

Constituent observations from the Upper Atmosphere Research Satellite (UARS) in combination with estimates of the residual circulation are used to examine the transport and chemical budgets of HF, CH₄ and O₃ in the summer Northern Hemisphere. Budget calculations of HF, CH₄ and O₃ show that the transport tendency due to the residual circulation increases in magnitude and is largely opposed by eddy motions through the summer months. Ozone budget analyses show that between 100 and 31 hPa, the magnitudes of the mean circulation and eddy transport terms increase through the summer months, producing tendencies that are …

Visions, Values, Valuation And The Need For An Ecological Economics, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

Practical problem solving in complex, humandominated ecosystems requires the integration of three elements: (1) active and ongoing envisioning of both how the world works and how we would like the world to be, (2) systematic analysis appropriate to and consistent with the vision, and (3) implementation appropriate to the vision. Scientists generally focus on only the second of these steps, but integrating all three is essential to both good science and effective management. Subjective values enter in the vision element, both in terms of the formation of broad social goals and in the creation of a preanalytic vision,which necessarily precedes …

Simultaneous Measurement Of Changes In Thickness And Refractive Index Of Weakly Absorbing Self-Standing Solid Films Using Optical Interferometry, Nalini Easwar, R. Fantini, E. Willis

Physics: Faculty Publications

A nondestructive optical interferometric method, which enables a direct and simultaneous measurement of small changes in both thickness and refractive index of thin films, is described. Optical interferometric methods are sensitive to the changes in the optical path length (the product of the refractive index and the physical thickness) through the film. Thus, when the film is subjected to changing environmental conditions such as changing temperature or humidity, it is a challenge to determine the change in thickness and the change in refractive index separately, using interferometry. By simultaneously monitoring two different sets of interference fringes, i.e., transmission and reflection …

A Security Analysis For Label Switching Routers, M. Al-Ibrahim, M. Savsar, W. Adi

Faculty of Informatics - Papers (Archive)

Label Switching Routers (LSR), such as IP switching of Ipsilon, use separate Virtual Circuits (VC)from different sources even having the same destination. Merging switches, on the other hand, allow multiple VCs of upstream traffic to use a single output VC if having same destination criteria. In this paper, we study IP switching of Ipsilon and identify certain security threats. We found that oscillation between routing and switching as a result of a malicious frequent suspension and releasing of flows is a main security threat that decreases performance of such systems. To stabilize the performance in face of such an attack, …

Mathematics Memory Verses: Weekly Devotionals For Math Class, Mark Colgan

ACMS Conference Proceedings 2001

Each Monday during the semester I start class with a short devotional on a verse that relates in some way to mathematics. After three weeks I choose one of the three at random for students to write out on their quiz for a possible bonus point. This encourages students to practice memorizing Scripture and it gives us the opportunity to discuss biblical principles that relate to some of the topics we are studying in the course.

I would like to share some of the Bible verses and weekly devotionals I have used in my mathematics classes. These can be organized …

Parables For Mathematicians: With Good News For Curved Beings, Ashley Reiter Ahlin

ACMS Conference Proceedings 2001

Because we often lack the language for talking about such deep matters, the things of God can be hard to understand or talk about. The things that we do see and know were made by the same God of whom we speak. Thus, they are reflections of His nature, purposes, and ways and can help us to think and take about Him. This presentation expresses a parable using the language of math.

Three Problems From Number Theory, Robert Brabenec

ACMS Conference Proceedings 2001

This paper discusses the experiences of Wheaton College mathematics and computer science department colloquium as they explored open-ended problems.

Theism & Mathematical Realism, John Byl

ACMS Conference Proceedings 2001

This paper examines connections between theism and mathematical realism. Mathematical realism, which offers the best account of mathematics, strongly supports theism. Theism, in turn, supports mathematical realism. Theism readily explains the intricate relations between mathematics, matter, and mind. The attributes of the biblical God provide justification for classical mathematics.

What Mathematical Paradoxes Teach Us About Paradoxes In Christianity, Paul Bialek

ACMS Conference Proceedings 2001

In Christian academic circles, we talk about the integration of our faith and learning. That is, we seek to discover and develop connections between our Christian faith and our particular discipline. This is notoriously difficult when the discipline is mathematics. I have found that asking myself these three questions has helped me to integrate my Christian faith with mathematics, although they could be applied to any discipline: (1) How does the fact that I am a Christian affect the way I view mathematics? (2) How does the fact that I am a mathematician affect the way I view Christianity? (3) …

Why Natural Selection Can't Design Anything, William A. Dembski

ACMS Conference Proceedings 2001

In The Fifth Miracle Paul Davies suggests that any laws capable of explaining the origin of life must be radically different from scientific laws known to date? The problem, as he sees it, with currently known scientific laws, like the laws of chemistry and physics, is that they cannot explain the key feature of life that needs to be explained. That feature is specified complexity. Life is both complex and specified. The basic institution here is straightforward. Davies rightly notes, laws (that is, necessities of nature) can explain specification but not complexity. Once life (or more generally some self-replicator) …

The Soviet Concept Of The Correlation Of Forces, James Bradley

ACMS Conference Proceedings 2001

This paper takes a look at the Soviet Union’s accumulation of nuclear weapons during the Cold War and what mathematical strategy they employed to make their choices.

Microcathodoluminescence Of Impurity Doping At Gallium Nitride/Sapphire Interfaces, S. H. Goss, X. L. Sun, A. P. Young, L. J. Brillson, David C. Look, Richard J. Molnar

Physics Faculty Publications

We have used low-temperature cathodoluminescence spectroscopy (CLS) to probe the spatial distribution and energies of electronic defects near GaN/Al₂O₃ interfaces grown by hydride vapor phase epitaxy (HVPE). Cross sectional secondary electron microscopy CLS shows systematic variations in impurity/defect emissions over a wide range of HVPE GaN/Sapphire electronic properties. These data, along with electrochemical capacitance–voltage profiling and secondary ion mass spectrometry, provide a consistent picture of near-interface doping by O diffusion from Al₂O₃ into GaN, over a range 100–1000 nm.

Ozone And Tracer Transport Variations In The Summer Northern Hemisphere Stratosphere, E. C. Cordero, S. R. Kawa

Eugene C. Cordero

Constituent observations from the Upper Atmosphere Research Satellite (UARS) in combination with estimates of the residual circulation are used to examine the transport and chemical budgets of HF, CH₄ and O₃ in the summer Northern Hemisphere. Budget calculations of HF, CH₄ and O₃ show that the transport tendency due to the residual circulation increases in magnitude and is largely opposed by eddy motions through the summer months. Ozone budget analyses show that between 100 and 31 hPa, the magnitudes of the mean circulation and eddy transport terms increase through the summer months, producing tendencies that are …

Cooperative Freezing In Spin Glasses And Magnetic Nanostructures, Ralph Skomski, Diandra Leslie-Pelecky

Diandra Leslie-Pelecky Publications

Relaxation processes in disordered nanostructures and spin glasses are investigated by examining the role of the magnetic anisotropy. To abstract from freezing processes associated with phase transitions, the consideration is restricted to a one-dimensional bond-disordered Ising spin glass. Using a Mattis-type gauge transformation, the spin glass is mapped onto a disordered ferromagnet. Based on the behavior of the spin chain we argue that spin-glass freezing is not necessarily related to a phase transition. The magnetic anisotropy, which is largely ignored in the Glauber approach to Ising dynamics, gives rise to cooperative deviations from the Arrhenius behavior and mimics Vogel–Fulcher relaxation. …

Molecular Dynamics Simulation Of Supersaturated Vapor Nucleation In Slit Pore. Ii. Thermostatted Atomic-Wall Model, K.T. Kholmurodov, K. Yasuoka, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Molecular dynamics simulations of nucleation of a supersaturated Lennard-Jones vapor in slit nanopores are carried out. In this study we extend a previous work [K. Yasuoka, G. T. Gao, and X. C. Zeng, J. Chem. Phys. 112, 4279 (2000)] in that the walls of the slit are treated as actual atomic walls serving as both the confining solid surfaces and a thermostat. The walls are fixed in place in a fcc lattice structure and wall atoms are subjected to a stiff biharmonic potential thereby bounded to lattice sites. The two walls of the slit have an identical surface [fcc (100)], …

Electronic Structure Of Superconducting Mgb₂ And Related Binary And Ternary Borides, Nadezhda I. Medvedeva, Alexander L. Ivanovskii, Julia E. Medvedeva, Arthur J. Freeman

Physics Faculty Research & Creative Works

First-principles full potential linear muffin-tin orbital-generalized gradient approximation electronic structure calculations of the new medium-T_c superconductor (MTSC) MgB₂ and related diborides indicate that superconductivity in these compounds is related to the existence of P_x,y-band holes at the γ point. Based on these calculations, we explain the absence of medium-T_c superconductivity for BeB₂, AlB₂, ScB₂, and YB₂. The simulation of a number of MgB₂-based ternary systems using a supercell approach demonstrates that (i) the electron doping of MgB₂ (i.e., MgB_2-yX_y with X=Be, …

Structural And Superconducting Properties Of La2-Xrxba2caycu4+Yo10+Δ (R=Nd, Gd; Y=2x) System, D. G. Kuberkar, R. S. Thampi, Nikesh A. Shah, Krushna Mavani, S. Rayaprol, R. G. Kulkarni, S. K. Malik, William B. Yelon

Physics Faculty Research & Creative Works

A Non superconducting La₂Ba₂Cu₄O_9+δ system has been made superconducting by the addition of CaCuO2, along with rare earth doping at the La site, with the stoichiometric composition La_2-xR_xCa_yBa₂Cu_4+yO_10+δ (R=Nd, Gd, and y=2x). All the samples with 0.0 < x < 0.5; y=2x were characterized by x-ray diffraction and neutron diffraction measurements for structural properties and by ac susceptibility, dc resistivity, and iodometric analysis for superconducting properties. The x=0.0 sample displays semiconducting behavior. Increasing x increases Tc from less than 15 K for Nd/Gd samples with x=0.1 to ∼78 K for x=0.5 samples. It is interesting to note that the hole concentration and T_c exhibit a strong correlation with increasing dopant concentration. Neutron diffraction studies confirm the occupancy of Ca and Nd ions at the La site with a concomitant displacement of La on to the Ba site. © 2001 American Institute of Physics.

Structure And Magnetic Studies On Uniald2.2, P. Raj, K. Shashikala, A. Sathyamoorthy, S. K. Malik, William B. Yelon

Physics Faculty Research & Creative Works

Heavy fermion itinerant antiferromagnetic UNiAl is one of the very few U-containing compounds which absorbs H2/D2 without disproportionation. The present neutron diffraction studies on UNiAlDy (y = 2.2) are directed towards resolving controversies with regard to the occupancy of Ni atoms and the associated interstitial sites for (H/D) atoms, as well as the nature of magnetic ordering in the higher hydride phase with y ≥ 2. The fit to the neutron diffraction data is found to improve considerably if the Ni atoms originally lying in the U-atoms' plane in UNiAl get shifted to the Ni-Al atoms' plane in the deuteride. …

Layer-Resolved Spin Polarization In Sb Overlayers On Nimnsb, Ralph Skomski, T. Komesu, C.N. Borca, H.-K. Jeong, Peter A. Dowben, D. Ristoiu, J.P. Nozie´Res

Peter Dowben Publications

The magnetism of antimony overlayers on a ferromagnetic substrate is investigated by spin-polarized inverse photoemission and explained in terms of a spin-dependent envelope-function approximation (SDEFA). The atomic structure of the films, which were deposited by sputtering Sb onto a NiMnSb(001) substrate, is characterized by a unique combination of three features: (i) NiMnSb is a highly spin-polarized semi-Heusler alloy predicted to be halfmetallic, (ii) antimony is a semimetal, exhibiting a band structure reminiscent of indirect-gap semiconductors, and (iii) the small lattice mismatch ensures a well-controlled interface. Combined x-ray absorption spectroscopy and spin-polarized inverse photoemission yield a layer-resolved spin polarization decaying on …

Self-Assembled Aggregates Of Neutral Nonlinear Optical Dyes In Smectite Clay Films, Mark Kostuk

Honors Theses

The field of photonics relies on nonlinear optical (NLO) materials and their unique light interacting properties to guide and manipulate light for such uses as optical switches and optical data storage. Hybrid organic-inorganic composites offer excellent routes to such materials synthesis. We report herein the first study of neutral organic NLO chromophores adsorbed onto hectorite and laponite clay films. Seven different dyes (disperse red 1; disperse red 13; disperse red 19; disperse orange 3; disperse orange 13; disperse orange 25, and DANS, [4-dimethylamino-4' -nitrostilbene]), and two exchangeable cations (sodium and zinc), are used to create the hybrid films. The nature …

Separation Of Chiral Controlled Substances Using Capillary Electrophoresis, Tania Magoon

Honors Theses

The separation of the chiral narcotic propoxyphene by capillary electrophoresis (CE) is the goal of this work. A three-way collaboration between our research group, Professor lsiah Warner (LSU) and the New York State Forensic Investigation Center is underway to separate propoxyphene enantiomers and to develop a protocol for the Forensic Center. We are investigating the application of both polymer surfactants and cyclodextrins as CE additives for the separation of enantiomeric propoxyphene. We have synthesized or obtained several polymerized N-undecylenyl-L-amino acid and N-undecylenyl-L-dipeptide derivatives as a pseudo-stationary phase in capillary zone electrophoresis for the separation of chiral compounds. Though no separation …

Interactions Between Oxazine Dyes And Sodium Dodecyl Sulfate Studied By Molecular Spectroscopy, Michael R. Webb

Honors Theses

We present the results of a fundamental investigation of how the presence of surfactant affects the self-interaction of cationic laser dyes in aqueous solution. Oxazine 1 and oxazine 170 are known to form non-fluorescent H-aggregates (n-stacked dimers). The interactions of each of these laser dyes with sodium dodecyl sulfate (SDS), a micelle forming, anionic surfactant, have been examined using UV-visible absorption and fluorescence spectroscopy, fluorescence anisotropy, and Rayleigh scattering. The colors of oxazine 170 solutions are visually distinguishable into three stages: solutions with no SDS, solutions with SDS below the erne (8mM), and solutions with SDS concentrations above the erne. …