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Articles 171121 - 171150 of 198086

Full-Text Articles in Engineering

Direct Electro-Oxidation Synthesis Of D-Arabinose On Spectroscopic Graphite Electrode, Hei Wei, Huang Ying Nov 1998

Direct Electro-Oxidation Synthesis Of D-Arabinose On Spectroscopic Graphite Electrode, Hei Wei, Huang Ying

Journal of Electrochemistry

D Arabinose synthesized by direct electro-oxidative decarboxylation of D gluconate on graphite electrode from aqueous solutions. The effects of D gluconate concentration, electrolysis potential, temperature and electrolyte composition on the current efficiency and product yield of electrosynthsis are discussed. The laboratory scale electrosynthesis was achieved with flow through cell. The optimum technology conditions for electrosynthesis were obtained with orthogonal design method. Both galvanostatic and potentionstatic conditions have been exploited, the later was found to be more effective.


The Study On The Performance Of Mcfc Matrix Prepared By Flow Cast, Hua-Xin Lin, Bao-Lian Yi, Nai-Chao Li, Tian-Xi Qu, En-Jun Zhang, Lian-Yin Kong, Ying-Cai Chen Nov 1998

The Study On The Performance Of Mcfc Matrix Prepared By Flow Cast, Hua-Xin Lin, Bao-Lian Yi, Nai-Chao Li, Tian-Xi Qu, En-Jun Zhang, Lian-Yin Kong, Ying-Cai Chen

Journal of Electrochemistry

The matrix for MCFC were prepared by flow cast technique which gives reproducible and reliable results. Its mean pore radius is about 0.18 μm, and the porosity is about 65%. The performance of MCFC stacked with this type of matrix is 0.854 V at 200 mA/cm2.


Study On Ni-Co-S-Mo Alloys New Cathode Material For Aquous Electrolysis, Yuan-Shou Xie, Quan-Feng Liu Nov 1998

Study On Ni-Co-S-Mo Alloys New Cathode Material For Aquous Electrolysis, Yuan-Shou Xie, Quan-Feng Liu

Journal of Electrochemistry

The parameters of electrodeposion of Ni-Co-S-Mo alloy were studied. The experimental results indicate that the electrodeposition alloy shows high catalytic activity for hydrogen evolution reaction, as well as better mechanical strength and higher chemical stability. The mechanism of catalytic hydrogen evolution reaction on this type of alloy electrode was also investigated by means of polarization curve and cyclic voltametry.


Corrosion Characteristics Of Electrodeposited Ni-Mo-P Alloy Immersed In Nacl Solution, Yue Zeng, Hong-Xin Huang, Xiao-Ming Xiao, Shi-Xun Lian, Su-Wei Yao, He-Tong Guo Nov 1998

Corrosion Characteristics Of Electrodeposited Ni-Mo-P Alloy Immersed In Nacl Solution, Yue Zeng, Hong-Xin Huang, Xiao-Ming Xiao, Shi-Xun Lian, Su-Wei Yao, He-Tong Guo

Journal of Electrochemistry

The corrosion characteristics of electrodeposited Ni-Mo-P alloy immersed in 5wt.% NaCl solution were investigated using immersion, anodic polarization curves, XPS and AES analysis. The corrosion rates of amorphous Ni Mo P alloys are lower than that of crystalline Ni-Mo-P alloys. Anodic polarization curve experiments show that for the electrodeposited Ni-Mo-P alloys, the nickel mol fraction of which has in between 0.719 and 0.868, the corrosion potential moves to positive with the increase of P content, and the peak current value of active region increase with the increase of Mo content in alloys, though the effects of P content on the …


Study On Electrosynthesis Of Butyl Butyrate At Conducting Oxide Anode Support On Titanium, Jun-Xiang He, Jin-Cheng Zhou, Kang-Ning Chen Nov 1998

Study On Electrosynthesis Of Butyl Butyrate At Conducting Oxide Anode Support On Titanium, Jun-Xiang He, Jin-Cheng Zhou, Kang-Ning Chen

Journal of Electrochemistry

Synthesis of butyl butyrate by direct electroxidation of n butyl alcohol and the electrochemical behaviors of several selected conducting oxide electrodes (Pb/PbO2, Ti/PbO2, i/SnO2+Sb2O3/PbO2 and Ti/SnO2+Sb2O3+PdOx/PbO2) have been investigated. The results demonstrated that the intermediate layers of SnO2, Sb2O3 and PdOx could significantly decrease the interfacial resistance of the electrodes, and that the Ti/SnO2+Sb2O3+PdOx/PbO2 electrode possessed better electrocatelytic performance than others.


Oxygen Evolution Behavour On Ni Electrode In Koh Solution, Xiao-Yan Cao, Hua-Tang Yuan, Zuo-Xiang Zhou, Yun-Shi Zhang Nov 1998

Oxygen Evolution Behavour On Ni Electrode In Koh Solution, Xiao-Yan Cao, Hua-Tang Yuan, Zuo-Xiang Zhou, Yun-Shi Zhang

Journal of Electrochemistry

The steady-state polarization curves of oxygen evolution were measured at temperatures between 22~70 ℃ on Ni electrode in 30 wt.% KOH solution by galvanostat methode. The exchange current densities, Tafel slopes and transfer coefficients were studied. It was found that 40 ℃ is a special temperature, near which the kinetic parameters change abrupdy. The Tafel slopes for oxygen evolution reactions at higher overpotentials change from more than 120 mV to about 70 mV when the temperature raises to 40~70 ℃ from 22~35 ℃. Simultaneously, the heat of activation is changes from 79.88 kJ/mol to 55.32 kJ/mol. Moreover, the -(η/Τ) i …


Study Of The Effect Of Rare Earth Ions On Dna Using Cyclic Voltammetry And Spectroscopy, Hei-Bai Shen, Yu-Zhuan Kang, Hai-Feng Yang, Lin Yu, Zong-Rang Zhang Nov 1998

Study Of The Effect Of Rare Earth Ions On Dna Using Cyclic Voltammetry And Spectroscopy, Hei-Bai Shen, Yu-Zhuan Kang, Hai-Feng Yang, Lin Yu, Zong-Rang Zhang

Journal of Electrochemistry

The interaction between rare earth ions(e.g. Eu3+ ,Ce3+, Er3+, Sm3+, Tb3+, La3+ and Nd3+) and DNA had been investigated by using Cyclic Voltammetry, Ultraviolet and Raman Spectroscopy. After the adding of Ce3+ ion to DNA solution, the cathodic peak current of Ce3+ ion reduction was found to decrease obviously, and the anodic peak current to decrease even more significantly. Differential UV spectra of Ce3+ ion depicted hyperchromic effect after the reaction of these two species and a new peak of 272 nm was found. Differential …


The Study Of Poly [N-(3-Ferrocene Acetamino Propyl- Pyrrole] Film Modified Glucose Electrode, Cheng-Yun Tian, Jing Chen, Li Zhang Nov 1998

The Study Of Poly [N-(3-Ferrocene Acetamino Propyl- Pyrrole] Film Modified Glucose Electrode, Cheng-Yun Tian, Jing Chen, Li Zhang

Journal of Electrochemistry

A poly [N-(3-ferrocene-acetamino-propyl-pyrrole)] film modified electrode was fabricated and studied by cyclic voltammetric method. The result shows that the modified electrode can give stable redox peaks of ferrocene, and an obvious catalytic peak due to glucose. This modified electrode was used to tabricate a glucose sensor which operates at +0.2 V, so that the ascorbic acid or uric acid doesn't affect the accuracy detection of glucose concentration. The sensor has a linear range of 0.1~10 mmol/L glucose, which the period of long term stability and response time of the sensor are about ten days and 2 min.


Vacancy Clustering In Quenched Al-Li Solid Solution Alloys Studied By Doppler Broadening Spectroscopy, Hollis P. Leighly, P. G. Coleman Nov 1998

Vacancy Clustering In Quenched Al-Li Solid Solution Alloys Studied By Doppler Broadening Spectroscopy, Hollis P. Leighly, P. G. Coleman

Materials Science and Engineering Faculty Research & Creative Works

The clustering of vacancies in severely quenched Al-Li solid solution alloys, with Li content between 230 and 2760 ppm, has been studied using Doppler broadening spectroscopy. The alloy samples were initially annealed at 873 K in dry air or dry, pure nitrogen. The onset temperature for vacancy clustering in samples initially annealed in air was found to be 150 ± 10 K, 40 ± 15 K lower than for the nitrogen-annealed samples. This result is consistent with the migration of divacancies, formed as a result of the significant increase in vacancy concentration caused by Li migration to, and oxidation at, …


Asymptotic Decay Of Radius Of A Weakly Conductive Viscous Jet, A.F. Spivak, Yuris A. Dzenis Nov 1998

Asymptotic Decay Of Radius Of A Weakly Conductive Viscous Jet, A.F. Spivak, Yuris A. Dzenis

Nebraska Center for Materials and Nanoscience: Faculty Publications

Motion of a weakly conductive viscous jet accelerated by an external electric field is considered. Nonlinear rheological constitutive equation applicable for polymer fluids (Oswald–deWaele law) is applied. A differential equation for the variation of jet radius with axial coordinate is derived. Asymptotic variation of the jet radius at large distances from the jet origin is analyzed. It is found that the well-known power-law asymptote for Newtonian fluids with the exponent 1/4 holds for more general class of fluids, i.e., pseudoplastic (shear thinning) and dilatant (shear thickening) fluids with the flow index between 0 and 2. Dilatant fluids with the flow …


Trends. Straight Talk On Why Saddam Hussein Can't Go Straight, Ibpp Editor Nov 1998

Trends. Straight Talk On Why Saddam Hussein Can't Go Straight, Ibpp Editor

International Bulletin of Political Psychology

The author discusses Saddam Hussein's inability to give up nuclear weapons development.


Fertigation Basics, Charles M. Burt Nov 1998

Fertigation Basics, Charles M. Burt

BioResource and Agricultural Engineering

Fertigation is widely practiced with drip irrigation, yet remains very unsophisticated. Major areas which need improvement are (i) making certain the irrigation system applies water with a high DU (uniformity), (ii) using proper injection pumps and protection hardware, (iii) recognizing that chemicals can interact with each other and with water to form precipitates which will clog emitters, (iv) understanding of nutrient ratios in plants and soil, (v) recognizing that nitrogen fertilization requires attention to the type of nitrogen, and (vi) developing programs for spoon-feeding chemicals. This paper covers the first 4 topics, plus discusses some specific fertilizers.


Specific Heat And Transport “Anomalies” In Mixed Alkali Glasses, Peter F. Green, Richard K. Brow, James J. Hudgens Nov 1998

Specific Heat And Transport “Anomalies” In Mixed Alkali Glasses, Peter F. Green, Richard K. Brow, James J. Hudgens

Materials Science and Engineering Faculty Research & Creative Works

We show that changes in the relative mole fractions of Li2O and Na2O in alkali metaphosphate glasses lead to “anomalies” in the specific heat and structural relaxations. The heat capacity change between the liquid and glassy states, Δcp(Tg), at the calorimetric glass transition temperature, Tg, exhibits a minimum when the mole fractions of Li2O and Na2O are comparable. Moreover, systematic changes in the temperature dependence of the viscosity, η, i.e., changes in the “fragility” of the system, accompany these changes in mole fraction. This observed dependence …


Acuta Enews November 1998, Vol.27, No. 11 Nov 1998

Acuta Enews November 1998, Vol.27, No. 11

ACUTA Newsletters

In This Issue

Student Paper Competition

University of Oregon Overhauls Two-Way Radio Systems

Overheard on the Listserve

FTC Web Site: Information You Can Use

Board Report

DC at a Glance

Positions Available

Welcome New Members


Self-Enhancement Of Dynamic Gratings In Photogalvanic Crystals, Nickolai Kukhtarev, Sergei F. Lyuksyutov, Preben Buchhave, Tatiana Kukhtareva, K. Sayano, Partha P. Banerjee Nov 1998

Self-Enhancement Of Dynamic Gratings In Photogalvanic Crystals, Nickolai Kukhtarev, Sergei F. Lyuksyutov, Preben Buchhave, Tatiana Kukhtareva, K. Sayano, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

We have developed a compact closed-form solution of the band transport model for high-contrast gratings in photogalvanic crystals. Our solution predicts the effect of the photoconductivity and the electric field grating enhancement due to the photogalvanic effect. We predict a pronounced dependence of the steady-state photogalvanic current on the contrast of the interference pattern and an increase of holographic storage time due to the enhancement of the photoconductivity grating contrast. In the high contrast limit and a large photogalvanic effect the refractive index grating will be shifted from the position of the intensity modulation pattern, contrary to the usually adopted …


Flight Physician - November, 1998, Civil Aviation Medical Association Nov 1998

Flight Physician - November, 1998, Civil Aviation Medical Association

Browse all Civil Aviation Medical Association Newsletters

A twelve page newsletter of the Civil Aviation Medical Association. The newsletter provided news about civil aviation medicine and information related to the organization.


Model For Trace Metal Exposure In Filter-Feeding Flamingos At Alkaline Rift Valley Lake, Kenya, Yarrow M. Nelson, Ramesh J. Thampy, Gideon K. Motelin, Jackson A. Raini, Cynthia J. Disante, Leonard W. Lion Nov 1998

Model For Trace Metal Exposure In Filter-Feeding Flamingos At Alkaline Rift Valley Lake, Kenya, Yarrow M. Nelson, Ramesh J. Thampy, Gideon K. Motelin, Jackson A. Raini, Cynthia J. Disante, Leonard W. Lion

Civil and Environmental Engineering

Abstract—Toxic trace metals have been implicated as a potential cause of recent flamingo kills at Lake Nakuru, Kenya. Chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) have accumulated in the lake sediments as a result of unregulated discharges and because this alkaline lake has no natural outlet. Lesser flamingos (Phoeniconaias minor) at Lake Nakuru feed predominantly on the cyanobacterium Spirulina platensis, and because of their filter-feeding mechanism, they are susceptible to exposure to particle-bound metals. Trace metal adsorption isotherms to lake sediments and S. platensis were obtained under simulated lake conditions, and a mathematical model was …


Screen Printing Process Design Of Experiments For Fine Line Printing Of Thick Film Ceramic Substrates, Jianbiao Pan, Gregory L. Tonkay, Alejandro Quintero Nov 1998

Screen Printing Process Design Of Experiments For Fine Line Printing Of Thick Film Ceramic Substrates, Jianbiao Pan, Gregory L. Tonkay, Alejandro Quintero

Industrial and Manufacturing Engineering

Screen printing has been the dominant method of thick film deposition because of its low cost. Many experiments in industry have been done and many models of the printing process have been developed since the 1960’s. With a growing need for denser packaging and a drive for higher pin count, screen printing has been refined to yield high resolution prints. However, fine line printing is still considered by industry to be difficult. In order to yield high resolution prints with high first pass yields and manufacturing throughput, the printing process must be controlled stringently.

This paper focuses on investigating the …


A Slip-Line Field For Ploughing During Orthogonal Cutting, Daniel J. Waldorf, Richard E. Devor, Shiv. G. Kapoor Nov 1998

A Slip-Line Field For Ploughing During Orthogonal Cutting, Daniel J. Waldorf, Richard E. Devor, Shiv. G. Kapoor

Industrial and Manufacturing Engineering

Under normal machining conditions, the cutting forces are primarily due to the bulk shearing of the workpiece material in a narrow zone called the shear zone. However, under finishing conditions, when the uncut chip thickness is of the order of the cutting edge radius, a ploughing component of the forces becomes significant as compared to the shear forces. Predicting forces under these conditions requires an estimate of ploughing. A slip-line field is developed to model the ploughing components of the cutting force. The field is based on other slip-line fields developed for a rigid wedge sliding on a half-space and …


Santa Clara Magazine, Volume 40 Number 3, November 1998, Santa Clara University Nov 1998

Santa Clara Magazine, Volume 40 Number 3, November 1998, Santa Clara University

Santa Clara Magazine

8 - EARTHBOUND IN TUSCANY By Susan Vogel. Cultivating the soil and restoring a Tuscan farmhouse became regenerative physically and spiritually for SCU English professor Edward Kleinschmidt.

14 - PREMIES By Sue Frey. Kathy (Straus) VandenBerg '66 pioneers a rule-defying path, as she puts tenderness and love above tubes and isolation in caring for premature newborns.

18 - SEA HUNT By Connie Hinckley. SCU SCREEM team members probe the blue-black waters of the Arctic Ocean for historic bounty using high-tech robotics.

26 - THE VILLAGE PEOPLE By Kathleen (Nino) Castello '88. Some 40 years ago a community of ex-GIs and …


Comparison Of Water And Temperature Distribution Profiles Under Sand Tube Irrigation, Masoud Meshkat, Richard C. Warner, Stephen R. Workman Nov 1998

Comparison Of Water And Temperature Distribution Profiles Under Sand Tube Irrigation, Masoud Meshkat, Richard C. Warner, Stephen R. Workman

Biosystems and Agricultural Engineering Faculty Publications

Drip irrigation is one of the most efficient systems in delivering water to the plant root zone. Research has shown that the saturated, or nearly saturated, surface beneath the emitter may increase evaporation thereby reducing the irrigation efficiency. To increase the efficiency of surface applied drip irrigation on permanent tree crops a sand tube irrigation (STI) method was developed and tested. The sand tube method consists of removing a soil core beneath the emitter and filling the void with coarse sand. A weighing lysimeter was designed and instrumented to directly measure temporal evaporation during irrigation and for a period of …


The Symposium Proceedings Of The 1998 Air Transport Research Group (Atrg), Volume 2, Aisling Reynolds-Feighan, Brent D. Bowen, Uno Aviation Institute Nov 1998

The Symposium Proceedings Of The 1998 Air Transport Research Group (Atrg), Volume 2, Aisling Reynolds-Feighan, Brent D. Bowen, Uno Aviation Institute

Faculty Books and Monographs

UNOAI Report 98-4


The Symposium Proceedings Of The 1998 Air Transport Research Group (Atrg), Volume 1, Aisling Reynolds-Feighan, Brent D. Bowen, Uno Aviation Institute Nov 1998

The Symposium Proceedings Of The 1998 Air Transport Research Group (Atrg), Volume 1, Aisling Reynolds-Feighan, Brent D. Bowen, Uno Aviation Institute

Faculty Books and Monographs

UNOAI Report 98-3


The Symposium Proceedings Of The 1998 Air Transport Research Group (Atrg), Volume 3, Aisling Reynolds-Feighan, Brent D. Bowen, Uno Aviation Institute Nov 1998

The Symposium Proceedings Of The 1998 Air Transport Research Group (Atrg), Volume 3, Aisling Reynolds-Feighan, Brent D. Bowen, Uno Aviation Institute

Faculty Books and Monographs

UNOAI Report 98-5


Field Evaluation Of Efficient Building Technology With Photovoltaic Power Production In New Florida Residential Housing, Florida Solar Energy Center, Danny Parker Nov 1998

Field Evaluation Of Efficient Building Technology With Photovoltaic Power Production In New Florida Residential Housing, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

The objective of the project, sponsored by the Florida Energy Office and Sandia National Laboratories, is to test the feasibility of building very efficient residential buildings that when combined with utility-interactive PV power, exert little net demand on the utility during the summer peak demand period.

Two single family homes - one, a super efficient residence with a utility interactive photovoltaic (PV) system, and another, a control home - have been constructed in Lakeland, Florida. The PV residence, or PVRES, was constructed with many measures designed to make it more efficient (Fig.E-1). These include a white tile reflective roof system, …


Cracking The Shell To Student Learning: An Innovative Instructional Approach, John R. Olson, Paul Savory Nov 1998

Cracking The Shell To Student Learning: An Innovative Instructional Approach, John R. Olson, Paul Savory

Department of Industrial and Management Systems Engineering: Faculty Publications

Management and Industrial Engineering courses is motivating students to learn and apply the quantitative and managerial aspects of the material. The aim of our educational methodology is to not only teach and reinforce the core principles of the disciplines, but to have students develop a set of skills that will make them competitive in the classroom and the workforce. Teaching is why a university exists. As a result, the objective of our instructional approach is to attract and retain dedicated students to the fields of Operations Management and Industrial Engineering and to keep those students competitive and in focus with …


Robust Course-Boundary Extraction Algorithms For Autonomous Vehicles, Chris Roman, Charles Reinholtz Nov 1998

Robust Course-Boundary Extraction Algorithms For Autonomous Vehicles, Chris Roman, Charles Reinholtz

Graduate School of Oceanography Faculty Publications

Practical autonomous robotic vehicles require dependable methods for accurately identifying course or roadway boundaries. The authors have developed a method to reliably extract the boundary line using simple dynamic thresholding, noise filtering, and blob removal. This article describes their efforts to apply this procedure in developing an autonomous vehicle.


Chemicals For Fertigation, Charles M. Burt Nov 1998

Chemicals For Fertigation, Charles M. Burt

BioResource and Agricultural Engineering

No abstract provided.


Predictive Relationships For Uptake Of Organic Contaminants By Hybrid Poplar Trees, Joel Gerard Burken, Jerald L. Schnoor Nov 1998

Predictive Relationships For Uptake Of Organic Contaminants By Hybrid Poplar Trees, Joel Gerard Burken, Jerald L. Schnoor

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Twelve Organic Compounds Commonly Found at Hazardous Waste Sites Were Studied for Uptake by Hybrid Poplar Trees. the Vegetative Uptake of Many of These Compounds Has Not Previously Been Demonstrated for Plant Species Being Utilized for Phytoremediation, Such as Hybrid Poplar Trees. Experiments Were Conducted Hydroponically Utilizing 14C-Labeled Compounds to Ascertain Translocation and Fate. Predictive Relationships for the Translocation and Partitioning to Plant Tissues Were Developed from the Experimental Data. Translocation and Partitioning Relationships based on Compounds' Octanol- Water Partitioning Coefficients (100 K(Ow)) Produced the Best Results, But the Relationships Did Not Allow for Fully Accurate Prediction of Each Contaminant's …


Successive Galerkin Approximation Algorithms For Nonlinear Optimal And Robust Control, Timothy Mclain, Randal W. Beard Nov 1998

Successive Galerkin Approximation Algorithms For Nonlinear Optimal And Robust Control, Timothy Mclain, Randal W. Beard

Faculty Publications

Nonlinear optimal control and nonlinear H infinity control are two of the most significant paradigms in nonlinear systems theory. Unfortunately, these problems require the solution of Hamilton-Jacobi equations, which are extremely difficult to solve in practice. To make matters worse, approximation techniques for these equations are inherently prone to the so-called 'curse of dimensionality'. While there have been many attempts to approximate these equations, solutions resulting in closed-loop control with well-defined stability and robustness have remained elusive. This paper describes a recent breakthrough in approximating the Hamilton-Jacobi-Bellman and Hamilton-Jacobi-Isaacs equations. Successive approximation and Galerkin approximation methods are combined to derive …