Physical Sciences and Mathematics Commons^™

Traveling Waves In Rotating Rayleigh-Bénard Convection: Analysis Of Modes And Mean Flow, Janet Scheel, M. Paul, P. Fishcer

Janet D. Scheel

Numerical simulations of the Boussinesq equations with rotation for realistic no-slip boundary conditions and a finite annular domain are presented. These simulations reproduce traveling waves observed experimentally. Traveling waves are studied near threshhold by using the complex Ginzburg-Landau equation (CGLE): a mode analysis enables the CGLE coefficients to be determined. The CGLE coefficients are compared with previous experimental and theoretical results. Mean flows are also computed and found to be more significant as the Prandtl number decreases (from σ=6.4 to σ=1). In addition, the mean flow around the outer radius of the annulus appears to be correlated with the mean …

Decoupling Of Erosion And Precipitation In The Himalayas, D Burbank, Ann Blythe, J Putkonen, B Pratt-Sitaula, E Gabet, M Oskin, A Barros, T Ohja

Ann Blythe

The hypothesis that abrupt spatial gradients in erosion can cause high strain rates in active orogens has been supported by numerical models that couple erosional processes with lithospheric deformation via gravitational feedbacks1, 2, 3. Most such models invoke a 'stream-power' rule, in which either increased discharge or steeper channel slopes cause higher erosion rates. Spatial variations in precipitation and slopes are therefore predicted to correlate with gradients in both erosion rates and crustal strain. Here we combine observations from a meteorological network across the Greater Himalaya, Nepal, along with estimates of erosion rates at geologic timescales (greater than 100,000 yr) …

Using Information Literacy Standards To Improve Geoscience Courses, Aimee Dechambeau, Ira Sasowsky

Aimee deChambeau

Information literacy (IL) is the set of skills that enables a person to find, evaluate, and use information. Although IL is important in the geosciences, it is hard to teach because the information comes in so many forms. Most geoscience courses include work that implicitly addresses some IL issues. However, because of the importance of IL, it is worthwhile to explicitly include it as part of the curriculum. The Association of College and Research Libraries has developed Information Literacy Standards for Higher Education that may be used to assess an individual's level of information literacy. We introduce a method for …

Hall And Wolynes Reply [Reply To Comment On ‘‘Microscopic Theory Of Network Glasses’’], Randall W. Hall, Peter G. Wolynes

Randall W. Hall

Targeting The Transcriptional Machinery With Unique Artificial Transcriptional Activators, Brian Brennan, Zhiqian Wu, Garrette Belanger, Jenifer Lum, Aaron Minter, Steven Rowe, Annette Plachetka, Chinmay Majmudar, Anna Mapp

Brian B. Brennan

The link between a growing number of human diseases and misregulation of gene expression has spurred intense interest in artificial transcriptional activators that could be used to restore controlled expression of affected genes. To expand the repertoire of activation domains available for the construction of artificial transcriptional regulators, a selection strategy was used to identify two unique activation domain motifs. These activation domains bear little sequence homology to endogenous counterparts and bind to unique sites within the transcriptional machinery. A comparison with two well-characterized activation domains, VP2 and P201, demonstrated for the first time that functional potency is not solely …

Spectral Representation Of The Electrical Properties Of Layered Materials., Anthony Day, A. Mcgurn, D. Bergman, M. Thorpe

Anthony Roy Day

We present a spectral representation for the effective conductivity of two homogeneous layers joined at a rough interface. This spectral representation is closely related to the Bergman-Milton spectral representation for bulk composites, and is easily extended to multilayered materials. By comparing the layered system to a reference layered system that has a flat interface, we form a surface spectral density that captures all the effects of surface structure on the effective conductivity of the layered sample, and is independent of the conductivities of the two layers. Because of the anisotropy of the layered system there are two surface spectral densities, …

A Distance-Based Semantic Search Algorithm For Peer-To-Peer Open Hypermedia Systems, Jing Zhou, Vijay Dialani, David De Roure, Wendy Hall

Vijay Dialani

We consider the problem of content management in dynamically created collaborative environments. We describe the problem domain with the aid of a collaborative application in Open Hypermedia Systems, which allows individual users to share their link databases, otherwise known as linkbases. The RDF specification is utilised to express and categorise resources stored in a linkbase. This paper describes a semantic search mechanism to discover semantically related resources across such distributed linkbases. Our approach differs from the traditional crawler based search mechanism since it relies on the clustering of semantically related entities to expedite the search for resources in a randomly …

Reductivedesorption Of 11-Mercaptoundecanoic Acid Monolayers Modified By Covalent Attachment Of 1,3- And 1,4-Phenylenediamine, Mark Anderson, Richard Baltzersen

Mark R. Anderson

1,3- and 1,4-phenylenediamine were covalently attached to a self-assembled monolayer of 11-mercaptoundecanoic acid by formation of an amide bond. Bonding of the phenylenediamine isomers was confirmed by the presence of infrared features attributable to ring vibrational modes, the amide I vibration, and the amide II vibration in the reflection–absorption infrared spectrum of the modified interface. Reductivedesorption peak potentials were shifted by 120 mV for the monolayer modified by 1,4-phenylenediamine and by 90 mV for the monolayer modified by 1,3-phenylenediamine relative to the desorption potential of the unmodified 11-mercaptoundecanoic acid monolayer. These potential shifts represent 23 and 17 kJ/mol stabilization of …

Effect Of Sn Substituting For Sb On The Low-Temperature Transport Properties Of Ytterbium-Filled Skutterudites, J. Yang, D. Morelli, G. Meisner, W. Chen, Jeffrey Dyck, C. Uher

Jeffrey Dyck

We examine the effect of alloying Sn on the Sb site of ytterbium-filled skutterudites, a promising class of thermoelectric materials. We report measurements of the Hall effect, electrical resistivity, Seebeck coefficient, and thermal conductivity between 2 and 300 K on two series of samples having different ytterbium filling fractions: Yb0.19Co4Sb12-xSnx, with x=0, 0.05, 0.1, and 0.2, and Yb0.5Co4Sb12-xSnx, with x=0.5, 0.6, 0.8, 0.83, and 0.9. We find that the substitution of Sn does not lower the electron concentration of these samples, but rather gives rise to a p-type carrier. Hall measurement data for Yb0.5Co4Sb11.17Sn0.83 can be understood in the context …

Implications Of Distributed Crustal Deformation For Exhumation In A Portion Of A Transpressional Plate Boundary, Western Transverse Ranges, Southern California, Andrew Meigs, Dong Yule, Ann Blythe, Doug Burbank

Ann Blythe

Spatial and temporal patterns of exhumation are inextricably linked to patterns of crustal deformation because crustal deformation drives rock uplift. A new interpretation of a segment of the Pacific-North America transpressional plate boundary in southern California is analyzed in the context of crustal shortening, rock uplift, and exhumation. Deformation is partitioned between two structural anticlinoria formed above thrust faults that root into a mid-crustal décollement. The southern anticlinorium began growing after 5 Ma and is characterized by almost no topographic expression, rock uplift of ∼3 km, and exhumation of <1.2 km. Deposition in the Los Angeles basin on the south generally kept pace with growth of this anticlinorium. In contrast, the northern anticlinorium is younger, has a significant topographic expression, rock uplift of 2.5–4.0 km, and exhumation of ∼1.5–2 km. On-going surface uplift above the northern anticlinorium is suggested by the mismatch between the magnitude of rock uplift relative to the exhumation. These data emphasize that the distribution of deformation between faults in the upper and middle crust, crustal root formation in the lower crust, and flexural subsidence are primary controls of patterns of exhumation, which together dictate net surface uplift in active orogenic belts.

Geochemistry Of Kauai Shield-Stage Lavas: Implications For The Chemical Evolution Of The Hawaiian Plume, Scott Bogue, S. Mukhopadhyay, J.C. Lassiter, K.A. Farley

Scott Bogue

We measured He, Sr, Nd, Pb, and Os isotope ratios and major and trace element concentrations in stratigraphically and paleomagnetically controlled shield-stage lavas from Kauai, Hawaii. The range of 3He/4He ratios (17–28 RA) from Kauai is similar to that reported from Loihi and thus challenges the prevailing notion that high 3He/4He ratios are restricted to the preshield stage of Hawaiian magmatism. 3He/4He ratios vary erratically with stratigraphic position, and chronostratigraphic control from paleomagnetic data indicates very rapid changes in the 3He/4He ratios (up to 8 RA in ∼102 years). These variations in helium isotopic ratios are correlated with variations in …

Working Across Cultures, John Hooker

John Hooker

No abstract provided.

Ultrafast Two-Photon Free Induction Decay, D. Keusters, Peifang Tian, W. Warren

Peifang Tian

No abstract provided.

A Comparison Of Semi-Analytical And Numerical Solutions For The Microwave Heating Of A Lossy Material In A Three-Dimensional Waveguide, Prof. Tim Marchant

Tim Marchant

The microwave heating of a three-dimensional block in an infinitely long rectangular waveguide propagating the TE10 mode is considered. The electrical conductivity (the dielectric loss) is assumed to be a function of temperature, and modelled by the Arrhenius law. A coupled set of equations is obtained that describes the electromagnetic fields and the temperature distribution in the block. The numerical solutions of this problem are obtained by two methods, the well known FD-TD scheme and a frequency domain method which makes the further assumption that a single TE10 mode exists in the waveguide and material. The results show that an …

No Frictional Heat Along The San Gabriel Fault, California: Evidence From Fission-Track Thermochronology, M.A. D’Alessio, Ann Blythe, R Bu¨Rgmann

Ann Blythe

Large earthquakes generate frictional heat, and the magnitude of heating is related to the slip magnitude, the applied effective normal stress, and the frictional strength of the fault. We looked for evidence of this heating in apatite fission-track age and track-length distributions of samples from adjacent to and within the San Gabriel fault zone in southern California. The fault is thought to be an abandoned major trace of the San Andreas fault system active from 13 to 4 Ma and has since been exhumed from depths of 2–5 km. At our sample locality, as much as 40 km of total …

Micro Thermoelectric Cooler Fabrication: Growth And Characterization Of Patterned Sb2te3 And Bi2te3 Films ., Luciana Da Silva, M. Kaviany, A. Dehennis, Jeffrey Dyck

Jeffrey Dyck

A column-type micro thermoelectric cooler is being fabricated using p-type Sb2Te3 and n-type Bi2Te3 films (approximately 4 μm thick). The films are grown by thermal co-evaporation and patterned on Cr/Au/Ti/Pt (hot) connectors, which are deposited onto a silicon dioxide coated wafer. The column height is limited by control of the Te deposition rate. Although a high substrate temperature during thermoelectric film deposition is desired, it has been limited by the degradation of the photoresist used for patterning. The measured Seebeck coefficient and electrical resistivity of the thermoelectric films are reported, and preliminary results show that excess tellurium increases the Seebeck …

A Solvent-Free Claisen Condensation Reaction For The Organic Laboratory, John Esteb, Matthew Stockton

John Esteb

An experiment involving the Claisen condensation reaction for a first-year organic chemistry laboratory is presented. Claisen condensations are routinely covered in organic textbooks but owing to the long reaction times required to reach equilibrium in solution they are seldom explored in the undergraduate teaching laboratory. In this experiment, potassium tert-butoxide and ethyl phenylacetate are heated to 100 °C for 30 minutes under solvent-free conditions to produce 2,4-diphenyl acetoacetate in 80% yield. The solvent-free nature of this procedure greatly reduces the quantity of waste generated by students relative to typical carbonyl condensation experiments.

Note:Link is to the article in a …

A Solvent-Free Oxidation Of Alcohols In An Organic Laboratory, John Esteb, Michael Schelle, Anne Wilson

John Esteb

An oxidation experiment for a first-year organic chemistry class is presented. This oxidation utilizes a solid mixture of CuSO4•5H2O and KMnO4 prepared by mortar and pestle. The oxidations take place under solvent-free conditions and near quantitative yields are obtained for the reactions. Thin-layer chromatography is used to monitor the progress of the reaction. This experiment provides for the simple oxidation of a secondary alcohol to a ketone using a relatively nontoxic oxidizing agent under solvent-free conditions.

Note:Link is to the article in a subscription database available to users affiliated with Butler University. Appropriate login information will be required for …

Transport Coefficients Of Titanium-Doped Sb2te3 Crystals., P. Svanda, P. LošŤÁK, Č. Drašar, Jeffrey Dyck

Jeffrey Dyck

Titanium-doped single crystals (cTi = 0 to 2×1020 atoms cm-3) were prepared from the elements Sb, Ti, and Te of 5N purity by a modified Bridgman method. The obtained crystals were characterized by measurements of the temperature dependence of the electrical resistivity, Hall coefficient, Seebeck coefficient and thermal conductivity in the temperature range of 5-300 K. It was observed that with an increasing Ti content in the samples the electrical resistance, the Hall coefficient and the Seebeck coefficient increase. This means that the incorporation of Ti atoms into the Sb2Te3 crystal structure results in a decrease in the concentration of …

A Note On Asymptotic Zero Distribution Of Orthogonal Polynomials, William F. Trench

William F. Trench

No abstract provided.

Absolute Equal Distribution Of The Spectra Of Hermitian Matrices, William F. Trench

William F. Trench

No abstract provided.

Absolute Equal Distribution Of Families Of Finite Sets, William F. Trench

William F. Trench

No abstract provided.

Linear Perturbations Of A Nonoscillatory Second Order Differential Equation Ii, William F. Trench

William F. Trench

No abstract provided.