Physical Sciences and Mathematics Commons^™

Flow And Congestion Control For Internet Streaming Applications, Shanwei Cen, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

The emergence of streaming multimedia players provides users with low latency audio and video content over the Internet. Providing high-quality, best-effort, real-time multimedia content requires adaptive delivery schemes that fairly share the available network bandwidth with reliable data protocols such as TCP. This paper proposes a new flow and congestion control scheme, SCP (Streaming Control Protocol) , for real-time streaming of continuous multimedia data across the Internet. The design of SCP arose from several years of experience in building and using adaptive real-time streaming video players. SCP addresses two issues associated with real-time streaming. First, it uses a congestion control …

Combining Multi-Attribute Utility And Geographic Information For Boundary Decisions: An Application To Park Planning, Jeffrey Keisler, Ronald Sundell

Management Science and Information Systems Faculty Publication Series

The quality and value of an area depend primarily on what is found within its designated boundaries. To determine the value of such areas in terms of boundaries, we have developed a methodology for integrating multi-attribute utility functions with spatial analysis so that desirable, or appropriate, boundaries can be determined on the basis of the goals and objectives for the park. The key to successful evaluation is the development of measures for what decision makers value, rather than merely using what is easily measured. In a detailed example for planning of national parks, the fundamental objectives are conservation and societal …

Volcanology And Geochemistry Of Pliocene And Quaternary Basalts On Citadel Mountain, Lunar Crater Volcanic Field, Pancake Range, Nevada, Loretta D. Dickson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alkali basalts on Citadel Mountain form the southern margin of the Lunar Crater Volcanic Field (LCVF) in the central Great Basin, Nevada. Citadel Mountain comprised of a faulted, north tilted section of Tertiary andesite and ash-flow tuff is capped by Pliocene and Quaternary alkali basalt flows that erupted from six major cinder cones. The basalt flows on Citadel Mountain can be divided into two groups (older and younger) based on age and isotopic signatures. The older basalt group is characterized by higher ⁸⁷ Sr/⁸⁶Sr and lower E_Nd and the younger group has lower ⁸⁷Sr/⁸⁶Sr …

Statistics For Logisticians, Caroline Lubert

Caroline P Lubert

No abstract provided.

Windows 3.X Vs. Windows 95: Get Your Ring-Side Seat, Sonya Shepherd

Sonya S. Gaither

No abstract provided.

Combining Multi-Attribute Utility And Geographic Information For Boundary Decisions: An Application To Park Planning, Jeffrey Keisler, Ronald Sundell

Jeffrey Keisler

Combining Multi-Attribute Utility And Geographic Information For Boundary Decisions: An Application To Park Planning, Jeffrey Keisler, Ronald Sundell

Jeffrey Keisler

The quality and value of an area depend primarily on what is found within its designated boundaries. To determine the value of such areas in terms of boundaries, we have developed a methodology for integrating multi-attribute utility functions with spatial analysis so that desirable, or appropriate, boundaries can be determined on the basis of the goals and objectives for the park. The key to successful evaluation is the development of measures for what decision makers value, rather than merely using what is easily measured. In a detailed example for planning of national parks, the fundamental objectives are conservation and societal …

Photolithographic Patterning Of Vacuum-Deposited Organic Light Emitting Devices, Peifang Tian, P. E. Burrows, S. E. Forrest

Peifang Tian

We demonstrate a photolithographic technique to fabricate vacuum-deposited organic light emitting devices. Photoresist liftoff combined with vertical deposition of the emissive organic materials and the metal cathode, followed by oblique deposition of a metal cap, avoids the use of high processing temperatures and the exposure of the organic materials to chemical degradation. The unpackaged devices show no sign of deterioration in room ambient when compared with conventional devices fabricated using low-resolution, shadow mask patterning. Furthermore, the devices are resistant to rapid degradation when operated in air for extended periods. This work illustrates a potential foundation for the volume production of …

A Vegetation Based Approach To Biodiversity Gap Analysis In The Agastyamalai Region, Western Ghats, India, B. R. Ramesh, Shaily Menon, Kamaljit S. Bawa

Shaily Menon

Protected areas in India have historically been established on an ad hoc basis with little attention to the conservation value of an area. This study focuses on a set of protected areas in the Agastyamalai region of the Western Ghats (WG), India. We examine forest loss and land-use changes in the study area from the early 1900s to 1960 and from 1960 to 1990. We use GIS to perform a biodiversity gap analysis of the protected areas in the study site. We produce a detailed map of existing floristic types and use it to generate layers corresponding to floristic species …

Preface, Claus Hammer, Paul Andrew Mayewski, David Peel, Minze Stuiver

Earth Science Faculty Scholarship

This special issue of the Journal of Geophysical Research presents 47 papers developed from research on the two deep ice cores drilled in central Greenland during the years 1989-1993 by the U.S. Greenland Ice Sheet Project 2 (GISP2) and the European Greenland Ice Core Program (GRIP). In this "grand experiment," two large ice-core-drilling programs were combined. A major reason was to validate the presence of fast climate oscillations that could not be verified by a single deep ice core.

A 110,000-Year History Of Change In Continental Biogenic Emissions And Related Atmospheric Circulation Inferred From The Greenland Ice Sheet Project Ice Core, L. D. Meeker, Paul Andrew Mayewski, M. S. Twickler, S. I. Whitlow, D. Meese

Earth Science Faculty Scholarship

The 110,000-year record of ammonium concentrations from the Greenland Ice Sheet Project 2 (GISP2) ice core provides the basis for an analysis of terrestrial biological production and atmospheric circulation patterns involved in the transport of biologically produced ammonium to the Greenland atmosphere. The directly measured concentration series was selected for analysis, rather than that of estimated ammonium flux, after a detailed analysis of the relationship among ice core glaciochemical concentrations and a high-resolution simultaneous record of snow accumulation from the GISP2 core. Analysis of the ammonium concentration series shows that maxima in background levels of ammonium in the Greenland atmosphere …

The Co2 Concentration Of Air Trapped In Greenland Ice Sheet Project 2 Ice Formed During Periods Of Rapid Climate Change, H. J. Smith, M. Wahlen, D. Mastroianni, K. Taylor, Paul Andrew Mayewski

Earth Science Faculty Scholarship

The CO₂ content of air occluded in Greenland Ice Sheet Project 2 (GISP2) ice formed over two separate intervals of rapidly changing climate, centered at approximately 46 and 63 kyr B. P., is as much as 90 ppm more during warm periods (interstadials) than during cold periods (stadials). These CO₂ variations are superimposed on changes in annual layer thickness and δ¹⁸O of the ice and do not show the 200- to 700-year offsets which would be expected for concurrent variations in the atmosphere and the ice. The CO₂ concentrations during the stadials are similar to …

Electrical Measurements On The Greenland Ice Sheet Project 2 Core, Kendrick C. Taylor, Richard B. Alley, Gregg W. Lamorey, Paul Andrew Mayewski

Earth Science Faculty Scholarship

The Greenland Ice Sheet Project 2 (GISP2) electrical conductivity measurement (ECM) record is an indication of the concentration of H+ in the core. The ECM detected seasonal variations in the nitrate concentration of the core which were used to assist in dating the core by annual layer counting. Volcanic eruptions that produce acidic aerosols are recorded in the ECM record. Evidence of biomass burning is detected by the ECM because fire-related ammonium emissions neutralize the acids in the core. Rapid climate transitions associated with the Younger Dryas and Dansgaard/Oeschger interstadial events alter the concentration of alkaline dust and are detected …

Paleoclimatic Variability Inferred From The Spectral Analysis Of Greenland And Antarctic Ice-Core Data, R. Yiou, K. Fuher, L. D. Meeker, J. Jouzel, S. Johnsen, Paul Andrew Mayewski

Earth Science Faculty Scholarship

Paleoclimate variations occur at various time scales, between a few centuries for the Heinrich events and several hundreds of millenia for the glacial to interglacial variations. The recent ice cores from Greenland (Greenland Ice Core Project and Greenland Ice Sheet Project 2) and Antarctica (Vostok) span at least one glacial oscillation and provide many opportunities to investigate climate variations with a very fine resolution. The joint study of cores from both hemispheres allows us to distinguish between the sources of variability and helps to propose mechanisms of variations for the different time scales involved. The climate proxies we analyze are …

The Greenland Ice Sheet Project 2 Depth-Age Scale: Methods And Results, D. A. Meese, A. J. Gow, R. B. Alley, G. A. Zielinski, P. M. Grootes, M. Ram, K. C. Taylor, Paul Andrew Mayewski, J. F. Bolzan

Earth Science Faculty Scholarship

The Greenland Ice Sheet Project 2 (GISP2) depth-age scale is presented based on a multiparameter continuous count approach, to a depth of 2800 m, using a systematic combination of parameters that have never been used to this extent before. The ice at 2800 m is dated at 110,000 years B.P. with an estimated error ranging from 1 to 10% in the top 2500 m of the core and averaging 20% between 2500 and 2800 m. Parameters used to date the core include visual stratigraphy, oxygen isotopic ratios of the ice, electrical conductivity measurements, laser-light scattering from dust, volcanic signals, and …

Volcanic Aerosol Records And Tephrochronology Of The Summit, Greenland, Ice Cores, Gregory A. Zielinski, Paul Andrew Mayewski, L. David Meeker, Karl Grönvold, Mark D. Germani, Sallie Whitlow, Mark S. Twickler, Kendrick Taylor

Earth Science Faculty Scholarship

The recently collected Greenland Ice Sheet Project 2 (GISP2) and Greenland Ice Core Project ice cores from Summit, Greenland, provide lengthy and highly resolved records of the deposition of both the aerosol (H₂SO₄) and silicate (tephra) components of past volcanism. Both types of data are very beneficial in developing the hemispheric to global chronology of explosive volcanism and evaluating the entire volcanism-climate system. The continuous time series of volcanic SO₄²⁻ for the last 110,000 years show a strong relationship between periods of increased volcanism and periods of climatic change. The greatest number of volcanic …

Major Features And Forcing Of High-Atitude Northern Hemisphere Atmospheric Circulation Using A 110,000-Year-Long Glaciochemical Series, Paul Andrew Mayewski, Loren D. Meeker, Mark S. Twickler, Sallie Whitlow, Qinzhao Yang, W. Berry Lyons, Michael Prentice

Earth Science Faculty Scholarship

The Greenland Ice Sheet Project 2 glaciochemical series (sodium, potassium, ammonium, calcium, magnesium, sulfate, nitrate, and chloride) provides a unique view of the chemistry of the atmosphere and the history of atmospheric circulation over both the high latitudes and mid-low latitudes of the northern hemisphere. Interpretation of this record reveals a diverse array of environmental signatures that include the documentation of anthropogenically derived pollutants, volcanic and biomass burning events, storminess over marine surfaces, continental aridity and biogenic source strength plus information related to the controls on both high- and low-frequency climate events of the last 110,000 years. Climate forcings investigated …

Methanesulfonate In The Greenland Ice Sheet Project 2 Ice Core, E. S. Saltzman, P-Y. Whung, Paul Andrew Mayewski

Earth Science Faculty Scholarship

In this paper we present measurements of methanesulfonate in the Greenland Ice Sheet Project 2 (GISP2) ice core. Methanesulfonate is an atmospheric oxidation product of dimethylsulfide. The GISP2 methanesulfonate record contains information about the atmospheric loading of biogenic sulfur over the past 110 kyr and its relationship to climate change. The GISP2 data set supports the inferences made from the Renland ice core from Greenland that the glacial atmosphere over Greenland had reduced concentrations of biogenic sulfur compared with the present day [Hansson and Saltzman, 1993]. We conclude that the flux of biogenic sulfur from the North Atlantic Ocean …

Air-Snow Exchange Investigations At Summit, Greenland: An Overview, Jack E. Dibb, J L. Jaffrezo

Earth Sciences

The Greenland Ice Sheet Project 2 (GISP2) and Greenland Ice Core Project (GRIP) deep drilling programs at Summit, Greenland included support (both logistical and scientific) of extensive investigation of atmospheric transport and air-snow exchange processes of gases and particles relevant to the interpretation of the ice-core records. Much of the sampling for the air-snow exchange investigations was conducted at a unique solar-powered camp 30 km southwest of the GISP2 drill camp (even further from the GRIP camp) and was characterized by a high degree of international collaboration and cooperation. The wide range of expertise and analytical capabilities of the 20-plus …

Preparation Of High Rate Discharge Foamed Nicd Battery, Yuming Wang

Journal of Electrochemistry

A novel device of SC type foamed NiCd battery is presented, in which, the innerresistance of battery is appeared to be reduced, and the electrode performance is gained to very improved, and so, this battery can be suited to using of the powerdrive pistol drill.

Development Of A New Type Ni-S Evolution Hydrogen Electrode For Water Electrolysis, Xiaoyou Yuan

Journal of Electrochemistry

A new type evolution hydrogen electrode NiS(N) has been made from nickel plating electrode in NiSO4CS(NH2)2 bath by electrodeposition. It is analyzed by SEM and Xray energy spectrum. The NiS(N) electrode is different from the NiS(O) electrode (which is used in plant at present time) in surface metallograph configuration and surfer content. The results of measurement polarization curves and water electrolysis 480 hours at 5 000 A·m-2 show that the evolution hydrogen overpotential of NiS(N) electrode is decreased at least 160 mV relative to NiS(O) electrode and the stablisum of NiS(N) electrode is better than that of NiS(O) electrode.

Advances In Solid Polymer Electrolytes, Liming Ding, Shaojun Dong, Erkang Wang

Journal of Electrochemistry

The formation, classification, applications and iontransport mechanism studies of solid polymer electrolytes were reviewed. While the recent SPE reports on the preparation of novel materials, the full structure determinations of PEO/salt complexes, the exploration of iontransport mechanism and the applications in electrochemical devices being introduced, some prospects on the future SPE research were suggested. 84 references were quoted.

Calculation Of The Sacrificial Anode Resistance Utilizing Boundary Element Method, Jianhua Wu, Mingxian Sun, Guangzhou Liu, Guangzhang Chen

Journal of Electrochemistry

According to a kind of mathematic model set up for the cathodic protection potential field, the boundary element method (BEM) was used to study the working state of plate sacrificial anodes which were galvanically coupled to mild steel. In situ experiment showed that the current output and resistance of sacrificial anodes could be calculated more accurately using BEM than loiyd formula. On the basis of the calculation, the cathodic protection design would be more accurate. It was also investigated that the effect of the lengthtobreadth ratio (L/B) on current output and resistance of plate zinc anodes. The results demonstrated that …

Cyclic Voltammetric Investigation Of The Axial Coordination Effects Of Pyridine On The Redox Behaviours Of (Tpp)Co, Chuanwei Yan, Xiangqui Lin, Haichao Lin, Chunan Cao

Journal of Electrochemistry

The electrochemistry of (TPP)Co in presence of pyridine was investigated in dichloroethane solution by cyclic voltammetry. Upon the addition of pyridine to the solution, two reduction peaks of Co(Ⅲ)/Co(Ⅱ) at 0.25 and -0.40 V (SCE) were observed. It was infered that the peaks were belong to the reductions of the complex compounds with one and two axial pyridine, (TPP)Co(Ⅲ)(Py) and (TPP)Co(Ⅲ)(Py)2. Even though the mole ratio of added pyridine was less than 1 the reduction of Co(Ⅲ)/Co(Ⅱ) still mainly occured at -0.40 V, which evidently resulted from pyridine adsorption on the electrodes. Besides, it was observed that the reduction peak …

Mechanism Of Electrodeposition Of Cu/Co Multilayer Thin Films, Jiangyun Xue, Jixun Wu, Dejun Yang

Journal of Electrochemistry

The mechanism of electrodeposition of Cu/Co multilayer thin films has been studied by means of potentodynamic sweep, cyclic voltammetry sweep and AC impendance. The results indicated that the copper deposition is mass transfer controlled process and the cobalt deposition is related to the absorbed intermediate species such as Co(OH)ads. The cobalt ions first form Co(OH)ads, then was deoxygenated to cobalt on the electrode surface.

Study On The Electrochemical Behaviour Of Eu(Ⅲ) Tryptophane Imidazole Triple Complex, Huixia Wu, Zemin Wang, Xiaqin Wu, Haifeng Yang, Zongrang Zhand

Journal of Electrochemistry

Eu(Ⅲ)TryptophaneImidazole binary and triple complexes were synthesized. IR spectra indicate that the carboxy group of tryptophane and the N atom of imidazole are coordinated with Eu(Ⅲ) ion. Cyclic voltammetry was used to study the electrochemical behaviour of Eu(Ⅲ) ion, the mixture of Eu(Ⅲ) with tryptophane and imidazole, and Eu(Ⅲ) binary or triple complexes. Among the scan range of -0.4～-1.0 V (vs. SCE), all of these three kinds of systems depicted pseudoreversible electron transfer. The kinetic parameters including D and Ks were also evaluated. 

Study On Perchlorate Produced By Electrolysis With Oxygen Cathode, Zhigang Shao, Baolian Yi, Naichao Li, Ming Han

Journal of Electrochemistry

A new method of measuring the flow capacity of cell gas in the perchlorate cell process equipped with an oxygen cathode is applided to investigate the influence of changes in the concentration of solution (chloride, chlorate, perchlorate and metal ion) and changes in the operation parameters (current density, temperature and pH) on perchlorate current efficiency. The main abstacle that the oxygen cathode is used in the perchlorate cell process is put forward and a method is provided to resolve it.

The Effect Of Solution Composition On The Corrosion Behavior Of Electrodeposited Zinc Powder, Qingwen Li, Qin Yang, Xi Xia

Journal of Electrochemistry

Zinc powder as a widely anode material can be electrowon from ZnCl2 or ZnO+KOH media. The properties of zinc powder are likely to be modified with electrolytic conditions such as the composition of bath solution, electrolysis manner, current density and additives etc.. In this paper, we have discussed the effect of the compositions of bath solution on the microstructure and corrosion resistance of zinc powder.

The Initial Process Of Amophous Electroless Nickel, Yi Chi, Lei Zhang, Yijan Wang, Maoyuan Ma

Journal of Electrochemistry

The initial process and mophology of electroless nickel played a domination role in adhesive strenghth of EN coating. The structure of initial deposits on certain matrixes was observed by TEM analysis. The deposition of a extremaly fine grain film depended on relative contrast between a coating and a matrix in crystal lattice parameters. When the coating and matrix had similar srystal lattice parameters. A extremely fine grain film was obtained. On the contrary, when the crystal lattice parameters were very different, a amorphous structure was observed.

The Activity Of Alloy CuNi Electrode In Electroreduction Of Aromatic NitroCompounds, Chunan Ma, Shaoping Tong, Xiaojun Cheng, Hui Wang

Journal of Electrochemistry

CuNi alloy on the basis of copper at different ratio Cu/Ni are prepared by codepostion. The cathode activtiy of film are studied by steadystate polarization for electroreduction nitrobenzene (NB) and 1,5dinitroanthraquinone (1,5DNA) to paminophenol and 1,5diamino4,8dihydroanthraquinone respectly. The results show that the alloy cathodes at different ratio Cu/Ni have different exchange current density (io) and apparent activition energy (EA). The alloy (CN30) has maximal io  and minimal EA by codeposition at the following conditions: electrolyte: 0.05 mol/L CuSO4·5H2O+0.6 mol/L NiSO4·6H2O+0.25 mol/L Na3Cit·2H2O; current density: 0.6 A/dm2 , pH=6, temperature at 50 ℃. Compared with the common cathodes such as …