Physical Sciences and Mathematics Commons^™

Graded Index And Randomly Oriented Core-Shell Silicon Nanowires With Broadband And Wide Angle Antireflection, P. Pignalosa, H. Lee, L. Qiao, M. Tseng, Y. Yi

Publications and Research

Antireflection with broadband and wide angle properties is important for a wide range of applications on photovoltaic cells and display. The SiOx shell layer provides a natural antireflection from air to the Si core absorption layer. In this work, we have demonstrated the random core-shell silicon nanowires with both broadband (from 400nm to 900nm) and wide angle (from normal incidence to 60o) antireflection characteristics within AM1.5 solar spectrum. The graded index structure from the randomly oriented core-shell (Air/SiOx/Si) nanowires may provide a potential avenue to realize a broadband and wide angle antireflection layer

Stream Recession Curves And Storage Variability In Small Watersheds, Nir Y. Krakauer, Marouane Temimi

Publications and Research

The pattern of streamflow recession after rain events offers clues about the relationship between watershed runoff (observable as river discharge) and water storage (not directly observable) and can help in water resource assessment and prediction. However, there have been few systematic assessments of how streamflow recession varies across flow rates and how it relates to independent assessments of terrestrial water storage. We characterized the streamflow recession pattern in 61 relatively undisturbed small watersheds (1–100 km2 ) across the coterminous United States with multiyear records of hourly streamflow from automated gauges. We used the North American Regional Reanalysis to help identify …

Computational Insight With Monte Carlo Simulations, Boyan Kostadinov

Publications and Research

We introduce Monte Carlo simulations for estimating areas by playing a game of "darts". We also introduce simulations of random walks. We use compact, vectorized programming, based on the R language, for all computer simulations and visualizations, aimed at high school students. This presentation is based on the Invited, prime time lecture given at the summer camp for gifted high school students at City College of New York, July 13, 2011.

Formalizing Reusable Aspect-Oriented Concurrency Control, Neelam Soundarajan, Derek Bronish, Raffi Khatchadourian

Publications and Research

Java and its library provide powerful concurrency control mechanisms. However, their use can lead to similar synchronization code scattered across multiple classes, synchronization and functional code being tangled together, and similar code being duplicated in many applications. Aspect-oriented (AO) programming makes it possible to address these problems. However, the specific behavior of systems built using AO techniques can be challenging to comprehend. We propose a specification approach to precisely express such systems' critical concurrency and synchronization properties. We illustrate the method with a simple example.

Automated Auction Mechanism Design With Competing Markets, Jinzhong Niu

Publications and Research

Resource allocation is a major issue in multiple areas of computer science. Despite the wide range of resource types across these areas, for example real commodities in e-commerce and computing resources in distributed computing, auctions are commonly used in solving the optimization problems involved in these areas, since well designed auctions achieve desirable economic outcomes.

Auctions are markets with strict regulations governing the information available to traders in the market and the possible actions they can take. Auction mechanism design aims to manipulate the rules of an auction in order to achieve specific goals. Economists traditionally use mathematical methods, mainly …

Noncomputable Functions In The Blub-Shub-Smale Model, Wesley Calvert, Ken Kramer, Russell Miller

Publications and Research

Working in the Blum-Shub-Smale model of computation on the real numbers, we answer several questions of Meer and Ziegler. First, we show that, for each natural number d, an oracle for the set of algebraic real numbers of degree at most d is insufficient to allow an oracle BSS-machine to decide membership in the set of algebraic numbers of degree d + 1. We add a number of further results on relative computability of these sets and their unions. Then we show that the halting problem for BSS-computation is not decidable below any countable oracle set, and give a more …

A Statistical Method To Correct Radiometric Data Measured By Avhrr Onboard The National Oceanic And Atmospheric Administration (Noaa) Polar Orbiting Environmental Satellites (Poes), Md Zahidur Rahman, Leonid Roytman, Abdelhamid Kadik

Publications and Research

This paper apply an statistical technique to correct radiometric data measured by Advanced Very High Resolution Radiometers(AVHRR) onboard the National Oceanic and Atmospheric Administration (NOAA) Polar Orbiting Environmental Satellites(POES). This paper study Normalized Difference Vegetation Index (NDVI) stability in the NOAA/NESDIS Global Vegetation Index (GVI) data for the period 1982-2003. AVHRR weekly data for the five NOAA afternoon satellites NOAA-7, NOAA-9, NOAA-11, NOAA-14, and NOAA-16 are used for the China dataset, for it includes a wide variety or different ecosystems represented globally. GVI has found wide use for studying and monitoring land surface, atmosphere, and recently for analyzing climate and …

Melting Trends Over The Greenland Ice Sheet (1958-2009) From Spaceborne Microwave Data And Regional Climate Models, X. Fettweis, Marco Tedesco, M. Van Den Broeke, J. Ettema

Publications and Research

To study near-surface melt changes over the Greenland ice sheet (GrIS) since 1979, melt extent estimates from two regional climate models were compared with those obtained from spaceborne microwave brightness temperatures using two different remote sensing algorithms. The results from the two models were consistent with those obtained with the remote sensing algorithms at both daily and yearly time scales, encouraging the use of the models for analyzing melting trends before the satellite era (1958–1979), when forcing data is available. Differences between satellite-derived and model-simulated results still occur and are used here to identify (i) biases in the snow models …

Memorial To Charles Alexander Baskerville (1928–2009), Allen W. Hatheway, Ajitkumar Shah, Joseph J. Lifrieri, Nazrul I. Khandaker, Stanley Schleifer

Publications and Research

Charles Alexander Baskerville captured our imagination, as a senior colleague in the practice of engineering geology in New York City. “Charlie” held the seat of master Big Apple Geologist during his matured career. He was the source, he knew the possibilities, he was aware of the pitfalls of this most geologically complex of American cities. His final work was his greatest reach—the four bedrock geologic quadrangles of the city. Baskerville mapped New York City for more than fifty years. He was sought and given access to sites of bedrock and bedrock/ overburden interface on the various capitol construction projects undertaken …

Electromagnetic Wave Propagation In Two-Dimensional Photonic Crystals, Oleg L. Berman, Vladimir S. Boyko, Roman Ya. Kezerashvili, Yurii E. Lozovik

Publications and Research

No abstract provided.

Polycationic Glycosides, Robert Engel, Ishrat Ghani, Diego Montenegro, Marie Thomas, Barbara Klaritch-Vrana, Alejandra Castaño, Laura Friedman, Jay Leb, Leah Rothman, Heidi Lee, Craig Capodiferro, Daniel Ambinder, Eve Cere, Christopher Awad, Faiza Sheikh, Jaimelee Rizzo, Lisa-Marie Nisbett, Erika Testani, Karin Melkonian

Publications and Research

Cationic lipids have long been known to serve as antibacterial and antifungal agents. Prior efforts with attachment of cationic lipids to carbohydrate-based surfaces have suggested the possibility that carbohydrate-attached cationic lipids might serve as antibacterial and antifungal pharmaceutical agents. Toward the understanding of this possibility, we have synthesized several series of cationic lipids attached to a variety of glycosides with the intent of generating antimicrobial agents that would meet the requirement for serving as a pharmaceutical agent, specifically that the agent be effective at a very low concentration as well as being biodegradable within the organism being treated. The initial …

Two-Loop Leading Color Corrections To Heavy-Quark Pair Production In The Gluon Fusion Channel, R. Bonciani, Andrea Ferroglia, T. Gehrmann, A. Von Manteuffel, C. Studerus

Publications and Research

We evaluate the two-loop QCD diagrams contributing to the leading color coefficient of the heavy-quark pair production cross section in the gluon fusion channel. We obtain an analytic expression, which is valid for any value of the Mandelstam invariants s and t and of the heavy-quark mass m. Our findings agree with previous analytic results in the small-mass limit and with recent results for the coefficients of the IR poles.

A View Of The Universe From Siue’S Campus, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Moving Towards Adaptive Search In Digital Libraries, Udo Kruschwitz, M-Dyaa Albakour, Jinzhong Niu, Johannes Leveling, Nikolaos Nanas, Yunhyong Kim, Dawei Song, Maria Fasli, Anne De Roeck

Publications and Research

Information retrieval has become very popular over the last decade with the advent of the Web. Nevertheless, searching on the Web is very different to searching on smaller, often more structured collections such as digital libraries, local Web sites and intranets. One way of helping the searcher locating the right information for a specific information need is by providing well-structured domain knowledge to assist query modification and navigation. There are two challenges: acquiring the domain knowledge and adapting it automatically to the specific interests of the user community. We will outline how a domain model can be automatically acquired using …

Climate Change: The Fork At The End Of Now, Micha Tomkiewicz

Publications and Research

There are many books on global warming written entirely from a layman's perspective, and there is a great deal of scientific literature on this subject. But few if any books attempt to bridge the science to those who lack a rigorous background in mathematics, physics and chemistry-but who may be working on careers in environmental science and policy. The new text is designed to introduce the field of global climate change from a scientific perspective-but written in a way that is accessible to students with some or little science background. It reviews the basic principles of climatic thermodynamics and atmospheric …

The Maximum Rectilinear Crossing Number Of The Wheel Graph, Elie Feder

Publications and Research

We find and prove the maximum rectilinear crossing number of the wheel graph. First, we illustrate a picture of the wheel graph with many crossings to prove a lower bound. We then prove that this bound is sharp. The treatment is divided into two cases for n even and n odd.

Dissipative Macroscopic Quantum Tunneling In Type-I Superconductors, Ricardo Zarzuela, Eugene M. Chudnovsky, Javier Tejada

Publications and Research

We study macroscopic quantum tunneling of interfaces separating normal and superconducting regions in type-I superconductors. Mathematical model is developed, that describes dissipative quantum escape of a two-dimensional manifold from a planar potential well. It corresponds to, e.g., a current-driven quantum depinning of the interface from a grain boundary or from artificially manufactured pinning layer. Effective action is derived and instantons of the equations of motion are investigated. Crossover between thermal activation and quantum tunneling is studied and the crossover temperature is computed. Our results, together with recent observation of non-thermal low-temperature magnetic relaxation in lead, suggest possibility of a controlled …

A Bulk Inflaton From Large-Volume Extra Dimensions, Brian Greene, Daniel N. Kabat, Janna Levin, Dylan Thurston

Publications and Research

The universe may have extra spatial dimensions with large volume that we cannot perceive because the energy required to excite modes in the extra directions is too high. Many examples are known of such manifolds with a large volume and a large mass gap. These compactifications can help explain the weakness of four-dimensional gravity and, as we show here, they also have the capacity to produce reasonable potentials for an inflaton field. Modeling the inflaton as a bulk scalar field, it becomes very weakly coupled in four dimensions, and this enables us to build phenomenologically acceptable inflationary models with tunings …

Ssgss: The Spitzer-Sdss-Galex Spectroscopic Survey, Matthew J. O'Dowd, David Schiminovich, Benjamin D. Johnson, Marie A. Treyer

Publications and Research

The Spitzer-SDSS-GALEX Spectroscopic Survey (SSGSS) provides a new sample of 101 star-forming galaxies at z < 0.2 with unprecedented multi-wavelength coverage. New mid- to far-infrared spectroscopy from the Spitzer Space Telescope is added to a rich suite of previous imaging and spectroscopy, including ROSAT, Galaxy Evolution Explorer, Sloan Digital Sky Survey, Two Micron All Sky Survey, and Spitzer/SWIRE. Sample selection ensures an even coverage of the full range of normal galaxy properties, spanning two orders of magnitude in stellar mass, color, and dust attenuation. In this paper we present the SSGSS data set, describe the science drivers, and detail the sample selection, observations, data reduction, and quality assessment. Also in this paper, we compare the shape of the thermal continuum and the degree of silicate absorption of these typical, star-forming galaxies to those of starburst galaxies. We investigate the link between star formation rate, infrared luminosity, and total polycyclic aromatic hydrocarbon luminosity, with a view to calibrating the latter for spectral energy distribution models in photometric samples and at high redshift. Last, we take advantage of the 5-40 micron spectroscopic and far-infrared photometric coverage of this sample to perform detailed fitting of the Draine et al. dust models, and investigate the link between dust mass and star formation history and active galactic nucleus properties.

Mount Graham, Janet Butler Munch

Publications and Research

Mount Graham, in southern Arizona, is considered a sacred location by the Apaches. The remoteness and high elevation of the mountain makes it an ideal location for astronomical research. After protracted litigation suits, the University of Arizona prevailed and was allowed to establish the Mount Graham International Observatory on the site.

Dea With A Perfect Object: Analytical Solutions, Alexander Vaninsky

Publications and Research

For the main DEA models, adding a Perfect Object—that is, a virtual object that has the smallest inputs and greatest outputs—to a collection of actual objects permits obtaining solutions analytically. The paper derives formulas for the solutions and demonstrates that computations with them comprise simple operations with ratios of inputs and outputs while avoiding the use of linear programming (LP) algorithms. A numerical example illustrates the utility of the approach.

Associate Professor Makes Mark Composing, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Roofs Of Our Homes May Be Green Tomorrow, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Statistician Recommends A Dose Of Skepticism, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Physics Professor Leads Research Into Laser Uses, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Neath Studies, Teaches The Uncertainties Of Life, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

Quantum Entanglement Of A Tunneling Spin With Mechanical Modes Of A Torsional Resonator, Dmitry A. Garanin, Eugene M. Chudnovsky

Publications and Research

We solve Schr\"odinger equation describing a tunneling macrospin coupled to a torsional oscillator. Energy spectrum is studied for various quantum regimes. Magnetic susceptibility and noise spectrum are computed. We show that entanglement of the spin with mechanical modes of a subnanometer oscillator results in the decoherence of spin tunneling. For larger oscillators the presence of a tunneling spin can be detected through splitting of the mechanical mode at the resonance. Our results apply to experiments with magnetic molecules coupled to nanoresonators.

Renormalization Of The Tunnel Splitting In A Rotating Nanomagnet, Michael F. O'Keeffe, Eugene M. Chudnovsky

Publications and Research

We study spin tunneling in a magnetic nanoparticle with biaxial anisotropy that is free to rotate about its anisotropy axis. Exact instanton of the coupled equations of motion is found that connects degenerate classical energy minima. We show that mechanical freedom of the particle renormalizes magnetic anisotropy and increases the tunnel splitting.

Quantum Tunneling Of The Interfaces Between Normal-Metal And Superconducting Regions Of A Type-I Pb Superconductor, Eugene M. Chudnovsky, S Velez, A Garcia-Santiago, J A. Hernandez

Publications and Research

Evidence of a non-thermal magnetic relaxation in the intermediate state of a type-I superconducor is presented. It is attributed to quantum tunneling of interfaces separating normal and superconducting regions. Tunneling barriers are estimated and temperature of the crossover from thermal to quantum regime is obtained from Caldeira-Leggett theory. Comparison between theory and experiment points to tunneling of interface segments of size comparable to the coherence length, by steps of order one nanometer.

Thermal Diffractive Corrections To Casimir Energies, Daniel N. Kabat, Dimitra Karabali

Publications and Research

We study the interplay of thermal and diffractive effects in Casimir energies. We consider plates with edges, oriented either parallel or perpendicular to each other, as well as a single plate with a slit. We compute the Casimir energy at finite temperature using a formalism in which the diffractive effects are encoded in a lower dimensional non-local field theory that lives in the gap between the plates. The formalism allows for a clean separation between direct or geometric effects and diffractive effects, and makes an analytic derivation of the temperature dependence of the free energy possible. At low temperatures, with …