Engineering Commons^™

The Nuclear Security Science And Policy Institute At Texas A&M University, Claudio A. Gariazzo, Kelley H. Ragusa, David R. Boyle, William S. Charlton, Sunil S. Chirayath, Craig M. Marianno, Paul Nelson Jr.

International Journal of Nuclear Security

The Nuclear Security Science and Policy Institute (NSSPI) is a multidisciplinary organization at Texas A&M University and was the first U.S. academic institution focused on technical graduate education, research, and service related to the safeguarding of nuclear materials and the reduction of nuclear threats. NSSPI employs science, engineering, and policy expertise to: (1) conduct research and development to help detect, prevent, and reverse nuclear and radiological proliferation and guard against nuclear terrorism; (2) educate the next generation of nuclear security and nuclear nonproliferation leaders; (3) analyze the interrelationships between policy and technology in the field of nuclear security; and (4) …

Addressing Imbalances In Us Nuclear Economic And Nonproliferation Policies, Matthew S. Duchene, Howard L. Hall

International Journal of Nuclear Security

Foreign civilian nuclear start-ups have an increasing number of international partners capable of supplying fuel cycle technologies. The desire to prevent the spread of dual-use enrichment and reprocessing technology by asking partner states to rely on international fuel markets is a major obstacle for US negotiating civilian nuclear trade agreements, leading to delays. US participation in emerging nuclear markets is being undercut by foreign competition, leading to decreasing economic competition and influence in international nonproliferation issues. It is therefore necessary for the US to reinvest and complete its domestic nuclear fuel cycle and modify its process for implementing civilian nuclear …

Radiation Damage As A Possible Metal Chronometer For Pre-Detonation Nuclear Forensics, Edward T. Peskie, Howard L. Hall

International Journal of Nuclear Security

The better we can determine how long ago nuclear material was made, the sharper our tools for investigating seized nuclear materials. This paper examines the effects of radiation damage caused by the decay of uranium isotopes, and assesses how experts in nuclear forensics could use the analyses of these damaged regions to determine how much time has passed since metal samples were formed. It also draws parallels from fission track dating studies of mineral samples under geologic time, and proposes modifications to past publications on α-recoil track dating in order to determine the time since a metal sample was cast …

Bio-Fuel Alternatives In South African Airways (Saa) Operations - Is It An Effective Response To Vulnerability Over Carbon Taxes And Penalty?, Daniel Kwasi Adjekum

International Journal of Aviation, Aeronautics, and Aerospace

The paper did a comparative analysis of the carbon emission and European Union Emission Trading Surcharges (EU ETS) of South African Airways (SAA) current fleet that used aviation jet A1 fuel and the same fleet if it had used a 25% bio-fuel ‘drop in’ for the European routes within the first quarter of the 2014 flying year (FY 14). Operational data in terms of the flight scheduled, aircraft type, total time enroute, route stage length, passenger estimates were obtained through SAA’s flight operations website. An independent t–test was conducted to compare means of the emissions. The mean carbon dioxide …

National Culture And Business Resilience: An Exploratory Study Of Two Chinese Construction Firms Operating In Singapore, Low Sui Pheng, Gao Shang, Teo Wee Kiat Ken

Business Review

The study of national culture focuses on differences in values and beliefs among people of different nationalities. With the increasing globalization of economies around the world, the construction industry is inherently exposed to risk at an unprecedented level. This is particularly true for Chinese construction firms, which are aggressively setting up subsidiaries and branches all around the world as they partake in large-scale complex projects overseas. With the liberal foreign trade policies adopted by China after its reforms, domestic construction firms in China also face immense pressure from the international players that are now able to enter the Chinese construction …

Extraction And Characterization Of Cellulose Nanocrystals Produced By Acid Hydrolysis From Corn Husk, Piyaporn Kampeerapappun

Journal of Metals, Materials and Minerals

Corn husk is one of the agricultural residues represent abundant, inexpensive, and readily available source of renewable lignocellulosic biomass. Cellulose nanocrystals (CNCs) were extracted from corn husk by alkali and bleaching treatments followed by sulfuric acid hydrolysis treatment. The material obtained after each stage of the treatments was characterized. Morphological investigation was carried out using scanning electron microscope (SEM) and transmission electron microscopy (TEM). Fourier transform infrared (FTIR) spectroscopy showed the progressive removal of non-cellulosic materials. The crystallinity of corn husk and CNCs was also investigated using X-ray diffraction analysis (XRD). The highest crystallinity index value of this study is …

Preparation And Characterization Of Epoxidized Natural Rubber And Epoxidized Natural Rubber/Carboxylated Styrene Butadiene Rubber Blends, Saowaroj Chuayjuljit, Thongchai Nutchapong, Onusa Saravari, Anyaporn Boonmahitthisud

Journal of Metals, Materials and Minerals

In this study, epoxidized natural rubber (ENR) with 30 mol % epoxidation (ENR-30) was first prepared from natural rubber (NR) latex via in situ performic epoxidation using 0.5 M hydrogen peroxide and 0.75 M formic acid at 50C for 4 h. The prepared ENR-30 was blended with three different loadings of carboxylated styrene butadiene rubber (XSBR) (10, 20 and 30 wt%) in the latex stage. All ENR-30/XSBR blends had longer scorch time and cure time than neat ENR-30 as examined on a moving die rheometer. The tensile properties (tensile strength, modulus at 300% strain and elongation at break), thermal stability …

Effect Of Heating Rate On Morphology Of Anti-Reflective Tio2 Film Coated By Sol-Gel With Polyethylene Glycol, Kumpol Leelaruedee, Patama Visuttipitukul, Niti Yongvanich

Journal of Metals, Materials and Minerals

This research studies formation of thin porous TiO2 film prepared by Sol-gel process with spin coating. Polyethylene glycol with molecular weight of 6,000 g/mol (6kPEG) was used as a pore generating agent. The TiO2 film was calcination at 450C for 1 hour with different heating rate. It was found that heating rate strongly affects on morphology of TiO2 film due to grain coalescence. The lower heating rate tends to cause more coalescence resulting in coarsening of both grain and pore size. With higher heating rate, film density can be increased due to lower number of pores. On the other hand, …

Effect Of Temperature Dropping During Solution Treatment During Rejuvenation Heat Treatment On Final Microstructures In Cast Nickel Base Superalloy, Grade Inconel-738, Aimamorn Promboopha, Sureerat Polsilapa, Panyawat Wangyao

Journal of Metals, Materials and Minerals

Generally, the rejuvenation heat treatment of degraded turbine blades, which were made of cast nickel based superalloy, Grade Inconel 738, usually consist of solution treatment condition with temperature range of 1125C- 1205C for 3 hours and then following with double aging processes, which include primary aging at 1055C for 1 hour and secondary aging at 845C for 24 hours. However, in practical working conditions of reheat treatment processed, the possible change of temperature during solution treatment can be obtained by error or malfunction of heating furnace, which usually provides the temperature dropping down. To simulate this effect, the dropping temperature …

Peroxidase Inhibition Assay For The Detection Of Some Thiols By Carbon Screen Printed Electrodes Based On Square Wave Voltammetry, Wischada Jongmevasna, Orawon Chailapakul, Manchumas Hengsakul Prousoontorn

Journal of Metals, Materials and Minerals

Cassava peroxidase (CSP) from leaves of cultivar KU50 was used as an alternative peroxidase for the electrochemical detection of thiram and thiourea.Square-wave voltammetry (SWV) incorporated with screen-printed carbon electrode was applied for the investigation of peroxidase activity. It was based on the measurement of 3, 3-diaminobenzidine (DAB) electro active product catalyzed by CSP and horseradish peroxidase (HRP) in 0.04 M Britton-Robinson buffer, pH 6, containing urea hydrogen peroxide in 96-well microplate. The reaction mixture in the presence of either thiourea or thiram was performed in order to study their effects on DAB oxidation catalyzed by both peroxidases. From the result …

Bs News July/August

Building Services Engineering

No abstract provided.

Sandwich-Type Cobalt Tungstophosphate: Synthesis, Characterization And Catalytic Activity, Wimonrat Trakarnpruk, Aphiwat Wannatem, Jutatip Kongpeth

Journal of Metals, Materials and Minerals

odium tungstophosphate, Na9[HPW9O34].7H2O was synthesized by reaction in aqueous solution of sodium tungstate, phosphoric acid and acetic acid. It was used as a precursor for synthesis of sandwich-type cobalt tungstophosphate, K10[Co4(H2O)2(PW9O34)2].20H2O by reacting with cobalt chloride and potassium acetate. The potassium ion can be exchanged with tetrabutylammonium bromide. The characterization was carried out by means of elemental analysis, FT-IR, UV-vis diffuse reflectance spectroscopy (DR-UV-vis). The sandwich-type cobalt tungstophosphate was used to catalyze oxidation of cyclooctane with H2O2 as oxidant in absence and presence of phase transfer agent. The experimental results showed that with phase transfer agent, the sandwich-type cobalt tungstophosphate …

Properties Of Binary And Ternary Composites Of Polypropylene Containing Soybean Oil-G-Chitosan And Hydrophobic Phosphonated Silica, Natthaphop Suwannamek, Kawee Srikulkit

Journal of Metals, Materials and Minerals

PP/soybean oil-g-chitosan binary composite, PP/hydrophobic phosphonated silica binary composite, and PP/chitosan/hydrophobic phosphonated silica ternary composite were prepared. Firstly, the preparation of soybean oil-g-chitosan was carried out by surface hydrophobicity modification of chitosan powder with soybean oil maleate and hydrophobicallyphosphonated silica was prepared by silanization of phosphonated silica with hexadecyltrimethoxysilane (an organosilane). Binary and ternary composites were prepared using a twin screw extruder. It was found that soybean oil-g-chitosan not only caused a decrease in tensile strength but also enhanced flexibility of PP due to its plasticization effect. In the opposite direction, the addition of hydrophobic phosphonated silica resulted in an …

An Updated Mineralogical Analysis Of Sediment Materials From Three Therapeutically-Used Peruvian Lagoons, Maria Luisa Ceron Loayza, Jorge Aurelio Bravo Cabrejos, F. A. R. Navarro, F. Urcia Ch.

Journal of Metals, Materials and Minerals

Herein, we determine the elemental, structural and mineralogical characterization of samples collected in three Peruvian lagoons; likewise, we investigate the physical and chemical properties of their fractions, both clay and magnetic. These lagoons are located in the Chilca District, Cate Province, southern Lima Region, Peru; their morphology has been altered since we carried out a previous study five years ago. The physical analytical techniques we used were energy dispersive X-ray fluorescence (EDXRF); X-ray diffractometry (XRD); and transmission Msbauer spectroscopy (TMS), at room and liquid-helium temperatures, and at low and high velocities. The results indicate that dolomite is the main clayey …

A Developmental Model Of Research Mentoring, Renata A. Revelo, Michael Loui

School of Engineering Education Faculty Publications

We studied mentoring relationships between undergraduate and graduate students in a summer undergraduate research program, over three years. Using a grounded theory approach, we created a model of research mentoring that describes how the roles of the mentor and the student can change. Whereas previous models of research mentoring ignored student roles and treated mentor roles as static, our model focuses on the development of the mentoring relationship over time. Our model explains how conflicts can occur if the mentor role does not match the maturity level of the student.

Current Status And Prospect Of Cathode Materials For Lithium Sulfur Batteries, Lan Zhou, Ai-Shui Yu

Journal of Electrochemistry

Elemental sulfur has been extensively investigated as a promising candidate of cathode material for next generation lithium secondary batteries. However, some troublesome issues, such as the low electric conductivity of sulfur (5×10^-30 S·cm^-1) and the high solubility of lithium polysulfide intermediates in organic electrolytes, resulting in a low utilization of active material and a redox shuttling of dissolved polysulfide ions between the sulfur cathode and the lithium anode, which eventually leads to a deposition of insoluble and insulating Li₂S₂/Li₂S on the electrode surface and a fast reduction in the specific capacity. …

Research Status And Application Prospects Of Limnpo4 As A New Generation Cathode Material For Lithium-Ion Batteries, Lai-Fen Qin, Yong-Gao Xia, Li-Peng Chen, Hua-Sheng Hu, Feng Xiao, Zhao-Ping Liu

Journal of Electrochemistry

Olivine-structured lithium manganese phosphate (LiMnPO₄) has the following advantages: excellent thermal stability, low cost, high safety and environmental benignity. Importantly, the theoretical energy density of LiMnPO₄ is about 20% higher than that of commercialized LiFePO₄ due to its higher Li⁺ intercalation potential of 4.1 V (vs. Li⁺/Li). Moreover, the high operating voltage of LiMnPO₄ is compatible with present non-aqueous organic electrolytes of lithium-ion batteries. Therefore, LiMnPO₄ is considered as a next generation cathode material for lithium-ion batteries. However, LiMnPO₄ suffers from poor electronic conductivity and low lithium diffusivity, resulting in …

Preparations And Applications Of Layered Carbon And Layered Carbon-Pbso4 Composite, Shu-Kai Zhang, Hao Zhang, Wei-Hua Xue, Jie Cheng, Wen-Feng Zhang, Gao-Ping Cao, Hai-Lei Zhao, Yu-Sheng Yang

Journal of Electrochemistry

The layered carbon materials (similar to graphene) have been synthesized by chemical vapor deposition (CVD) on the cheap catalyst (potassium or sodium carbonate substrate). The layered-carbon- lead sulfate (PbSO₄) composite could be prepared by in situ chemical deposition based on the layered carbon. The XRD, SEM and TEM results showed that the layered carbon materials was amorphous carbon layer, and the composite was a compound made of fine lead sulfate grains and layered carbon. Thermogravimetric analysis determined the carbon content in the composite. Adding a certain amount of layered carbon or layered-carbon-PbSO₄ composite into negative active materials …

Electrochemical Mass Spectrometric Study Of Lithium-Oxygen Batteries, Xin-Xiu Yan, Li-Po Ma, Zhang-Quan Peng

Journal of Electrochemistry

Mass Spectrometry, coupled with electrochemistry, is a powerful research tool to study mechanisms for a broad range of electrode reactions by identifying and quantifying reaction products and intermediates. In this review, we summarize the recent advances in the Li-O₂ battery researches offered by electrochemical mass spectrometry based on our group investigations. These include the research progresses in electrolytes, cathode materials (electrocatalysts), and parasitic reactions, i.e., the key issues associated with Li-O₂ research. In addition, we also discuss the effects of irreversible side reactions involved in battery systems on charge and discharge processes.

Synthesis Of Graphene Wrapped Li-Rich Layered Metal Oxide And Its Electrochemical Performance, Meng-Yan Hou, Ke Wang, Xiao-Li Dong, Yong-Yao Xia

Journal of Electrochemistry

In present work, lithium-rich layered transition metal oxide (LLO) was synthesized by a co-precipitation method in combination with a solid-state reaction. The graphene wrapped Li-rich layered oxide composite (LLO/Gra) was obtained by sintering the LLO/GO composite at 300 ^oC for 30 min in an air. The morphologies and the electrochemical performances were characterized by means of SEM, TEM, XRD, XPS, EIS and charge/discharge tests. The results indicated that the LLOe particles were uniformly wrapped with graphene. The resulting material exhibited better rate capability than that of pristine LLO since the wrapped graphene demonstrated the enhanced electronic conductivity. Accordingly, the …

Research Progress In Carbon Coating On Lifepo4 Cathode Materials For Lithium Ion Batteries, Ning Zhang, Yong-Chang Liu, Cheng-Cheng Chen, Zhi-Qiang Zhu, Zhan-Liang Tao, Jun Chen

Journal of Electrochemistry

Olivine-structured LiFePO₄ has been received much attention because of its flat voltage profile, low cost, abundant material supply and better environmental compatibility. However, the poor electronic and ionic conductivities have limited its application in industry. One of the best methods to improve the electrochemical performance is carbon coating. In this review, we summarize the recent developments of LiFePO₄/C cathode. Moreover, the different effects caused by coating methods and carbon sources, as well as the mechanism of carbon coating on the properties of LiFePO₄/C are reviewed.

Enhancing Stability Of Pem Fuel Cell Catalysts Via Support Changing, Xiao-Hong Xie, Zi-Dong Wei

Journal of Electrochemistry

The Pt/C catalyst with highly dispersed Pt nanoparticles supported on carbon has been widely used as the state-of the-art catalyst in proton exchange membrane fuel cells (PEMFCs), while the durability of Pt/C is one of the major barriers for large-scale applications of PEMFCs. Thus, enhancing the stability of Pt/C has been a hot issue in this field. In this review, we summarize the recent progress in enhancing the catalyst stability in the view of support material. The future prospects of the PEMFCs catalyst should focus on adopting more stable supports or strengthening the interactions between Pt and supports.

Pt/C Modified Proton Exchange Membrane For Improved Fuel Cell Performance, Zhi Cui, Chao Wang, Shui-Yun Shen, Feng-Jing Jiang, Jun-Liang Zhang

Journal of Electrochemistry

The property of proton exchange membrane greatly affects the performance of proton exchange membrane fuel cells (PEMFC). During the operation of a PEMFC, the water produced at the cathode, the water vapor from the humidified feed gas and the water migrated by electro-dragging will reach a balance in the membrane and determine the resistance of PEMFC, and thus affect the performance of PEMFC. Normally, the PEMFC performance strongly depends on the relative humidity of the feed gas, and the performance decreases at lower humidity as a result of lower proton conductivity of the membrane. In this paper, we proposed to …

Lithium Air Batteries: Non-Aqueous And Hybrid Systems, Sheng-Fu Tong, Ping He, Xue-Ping Zhang, Shi-Yong Zhao, Hao-Shen Zhou

Journal of Electrochemistry

Developing energy storage devices and new materials, which match the requirements in electric vehicles (EVs) and hybrid electric vehicles (HEVs), is an effective way to balance the contradiction between the social development and the shortage of fossil energy and environment pollution. Rechargeable lithium-air (Li-air) batteries consisting of Li and oxygen as the anodic and cathodic reactants, respectively, have attracted much attention during the past decade due to their high theoretical specific energy. According to work conditions, the most studied types of Li-air batteries are non-aqueous, hybrid, and solid state electrolyte Li-air batteries. Challenges still exist in cathodes, anodes, electrolytes and …

Electrolytes For Lithium And Lithium-Ion Batteries, Zong-Rang Zhang

Journal of Electrochemistry

This is an up-to-date book published by Springer last year and focuses on the field of the electrolytes for lithium and lithium-ion batteries. A brief introduction and review of this book are given in this paper. The main contents of this book are introduced briefly in the order of ten different chapters along with a short review of recent progress in those fields.

Preparation Of Zro2-Doped Nb/Pbo2 Electrode And Electrocatalytic Performance Of Methyl Orange Degradation, Li Zhang, Wen-Yan Dong, Tai-Lai Yang, Zhen-Hai Liang

Journal of Electrochemistry

The zirconium oxide (ZrO₂)-doped niobium based lead oxide (Nb/PbO₂) electrode was prepared by electrodeposition. The microstructures and electrochemical properties of Nb/ZrO₂+PbO₂ electrode were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), linear sweep voltammetry, electrochemical impedance spectroscopy and cyclic voltammotry. In addition, the Nb/PbO₂ electrode was used as an anode for the electrochemical degradation of methyl orange (MO). Results revealed that the ZrO₂ doping made the Nb/PbO2 electrode surface denser and rougher with smaller sized crystal particles, which increased the specific surface area and enhanced the electrocatalytic activity of the …

Consumer Perceptions Towards Package Designs: A Cross Cultural Study, Romica Chandra Lal, Fritz Yambrach, Lucy Mcproud

Journal of Applied Packaging Research

The choice of one package or the other can be an economic decision or can be influenced by cultural acceptance or perception of individual convenience. Product package systems can be designed for one-time use or multiple-use purposes. Package perceptions in different countries typically develop from a variety of factors, including climate, lifestyle, and cultural acceptance with regard to particular products. In an increasingly global economy with multinational firms marketing products worldwide, it is important to understand the differences between consumer needs and consumer responses to product-package systems.

The objective of this research was to examine consumer perceptions of different product …

Effects Of Various Extrapolation Techniques For Abbreviated Dynamic Modulus Test Data On The Mepdg Rutting Predictions, Minkyum Kim, Louay N. Mohammad, Mostafa A. Elseifi

Journal of Marine Science and Technology–Taiwan

Abbreviated dynamic modulus test protocols have been used to reduce the time and cost of running the test for routine uses. The abbreviated test results can then be extrapolated to estimate the complete array of the dynamic modulus values required for the Level 1 MEPDG analysis. Multiple approaches are available for the extrapolation depending on a master curve and shift factor functions chosen. The objective of this study was to identify the best practice of extrapolating the abbreviated dynamic modulus data by evaluating the accuracy of performance predictions through MEPDG pavement analysis. Two common sigmoid functional forms (i.e., the MEPDG …

Combined Effects Of Temperature And Moisture Content On Soil Suction Of Compacted Bentonite, Shu-Rong Yang, Wei-Hsing Huang, Shao-Hung Chung

Journal of Marine Science and Technology–Taiwan

Based on experimental determination of soil suctions of two clayey soils, this study investigated the combined effects of temperature and moisture content on soil suction. First, two clayey soils were statically compacted at target moisture contents ranging from 5% to 20%, such that a broad spectrum of compaction conditions can be evaluated. Then, filter paper method and thermocouple psychrometer were adopted to measure soil suction, including total and matric suctions, at temperatures ranging from 10°C to 60°C. It was found that soil suctions of expansive soils vary with compaction parameters such as compaction moisture content and compaction effort, and that …

Preliminary Study On The Correlation Between Two-Dimension Surface Texture And Friction, Shih-Huang Chen, Kuan-Lun Hsu, Pei Liu, Hung-Wen Chung

Journal of Marine Science and Technology–Taiwan

The friction of pavement is mainly determined by the microtexture of the surface layer. However, the finer degree of microtexture makes it impossible to observe with naked eye. The object of this study was to develop a High Definition Scan Texture Machine (HDSTM) with 2D Laser CCD to support previous research on the correlation between texture and friction. In addition, this study proposed seven different parameters and sought to find an index for an ideal correlation that could represent the entire pavement texture. By assessing the test results, the Segment of Average Profile Depth (SAPD) was selected as the texture …