157 research outputs found

    Forensic, Archaeological and Related Application of Inductively Coupled Plasma Mass Spectrometry

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    Inductively coupled plasma spectrometry (ICP-MS) is a powerful analytical instrument that can be applied to multiple disciplines for trace elements detection. In the first stage of this research, ICP-MS was used to group archaeological pottery sherds based on the compositional information obtained. Provenience of the pottery was evaluated using multivariate analysis. Results were compared with those obtained on the same data set using neutron activation analysis (NAA). It was found that the groups generated in this study were comparable to the previous ones, and more details within groups were observed. In the second stage of this research, ICP-MS was applied to a current forensic problem, the characterization of gunshot residue (GSR). The technique was found to be useful in comparison between shooters and non-shooters using inorganic GSR, mainly antimony, barium, and lead. Not only is the concentration on shooter\u27s hand higher, but also the dominant element is different from non-shooters. Lead isotope ratio can be determined by ICP-MS and assist in the differentiation of handguns and ammunitions. Two handguns and four ammunitions used in this study were differentiated by the biplot of mean of lead isotope ratio 208/206 against lead concentration. In the final stage of this research, ICP-MS was used to determine the concentration of inorganic elements in hair collected from mining and control areas. This work was done in concert with the Department of Community Medicine at the WVU Health Sciences Center. A unique aspect of this work was the extremely small sample size available for analysis. The results showed a depletion of chromium, manganese and iron, and an enrichment of aluminum, zinc, and arsenic in samples from mining area. Similar patterns of elemental concentration were also found in mining versus control areas and cancer versus non-cancer groups

    Probing confined interfacial excitations in buried layers by Brillouin light scattering

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    Brillouin light scattering from silicon oxynitride films grown on GaAs reveals a low frequency elastic wave excitation at frequencies lying below that of the Rayleigh surface wave. This mode, identified as an excitation localized by the interface, arises from the presence of a soft, thin transition layer between the film and substrate. Observations of this low frequency excitation offer a previously unexplored approach to characterize, non-destructively, the properties of buried interfaces.Comment: 4 pages, 4 figures, key words: interface, interfacial waves, guided acoustic waves, acoustic waveguid

    Aggregate Economic Implications of New Technologies in Energy Industry

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    This thesis studies technological progress in the energy sector and the transition path from fossil fuels to renewable energy, with a particular emphasis on the conse- quences to the whole economy. Currently, there is an active discussion regarding sub- sidizing renewable energy sources, which are often portrayed as the sole future source of energy and the driver of signi cant employment and economic growth. However, innovation in the fossil fuel sector and its continuing development can also be a game changer and should not be ignored. In the rst chapter, we use a dynamic general equilibrium model with endogenous technological progress in energy production to study the optimal transition from fossil fuels to renewable energy in a neoclassical growth economy. We emphasize the importance of modeling technology innovation in the fossil fuel sector, as well as in the renewable energy industry. Advancements in the development of shale oil and gas increase the supply of fossil fuel. This implies that the \parity cost target" for renewables is a moving one. We believe that this important observation is often neglected in policy discussions. Our quantitative analysis nds that these advancements allow fossil fuels to remain competitive for a longer period of time. While technological breakthroughs in the fossil fuel sector have postponed the full transition to renewable energy, they have also created many jobs and stimulated local economies. In the third chapter, we use an econometric analysis to compare job creation in the shale gas and oil sectors with that in the wind power sector in Texas. The results show that shale development and well drilling activities have brought strong employment and wage growth to Texas, while the impact of wind industry development on employment and wages statewide has been either not statistically signi cant or quite small. The rst and third chapters question the current enthusiasm in policy circles for only focusing on alternative energy. Chapter 2 provides some theoretical support for subsidizing renewable energy development. Here we develop a decentralized ver- sion of the model in Chapter 1 and allow for technological externalities. We analyze the e ciency of the competitive equilibrium solution and discuss in particular dif- ferent scenarios whereby externalities can result in an ine cient outcome. We show that the decentralized economy with externalities leads to under-investment in R&D, lower investment and consumption, and delayed transition to the renewable economy. This may provide an opportunity for government action to improve private sector outcomes

    HIV/AIDS knowledge in detention in Hunan province, China

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    BACKGROUND: Injection drug use (IDU) is one of the major modes of HIV transmission in China. Drug use is illegal in China, all identified drug users are registered by Public Security Bureau, and most were sent to detention; most detainees engaged in high risk behaviours. In order to well understand the HIV/AIDS knowledge among detainees, a survey was conducted in different detention settings in Hunan province in 2008 to assess knowledge and attitudes about HIV among detainees and to provide useful information for HIV prevention and intervention strategies in detention centers. METHODS: A cross-sectional survey was conducted in 10 detentions in Hunan province, China, and demographic information along with knowledge and attitude of HIV/AIDS was collected through standardized interviews. Descriptive statistics were used to describe HIV knowledge, attitudes, and education services among detainees. RESULTS: There were 956 detainees interviewed from 10 detention centers. The male to female ratio was 2.24:1. The majority detainees received nine years of compulsory education, accounting for 51.5%. There were nine questions to assess HIV/AIDS knowledge of detainees, and 35.7% of those surveyed answered all nine questions correctly. There were 92.3% (882/956) who consented to be informed about the HIV antibody test results when tested, and 81% (774/956) elected that their family members were also informed. All detention centers had an organized HIV/AIDS education program. CONCLUSION: This study gives us an overview about HIV/AIDS knowledge in detention in Hunan province, and all detention sites in the study provided HIV/AIDS intervention services among detainees that focused on HIV/AIDS knowledge, attitude, and health behaviors

    Non Destructive Determination Of Elastic Moduli By Two Dimensional Fourier Transformation And Laser Ultrasonic Technique

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    Broadband laser ultrasonics and two dimensional Fourier transformation are used to characterize the properties of varieties of foils and plates. Laser ultrasonics generation is achieved by use of a pulsed laser which deposits pulsed laser energy on the surface of the specimen. The displacement amplitude of the resulting broadband ultrasonic modes are monitored using a two wave mixing photo-refractive interferometer. By applying a two dimensional Fourier transformation to the detected spatial and temporal displacement waveforms, the images of density of state (DOS) for the excited ultrasounds are obtained. Results are presented for a 150 um thick paper sample, a 52.8 um stainless steel foil and a 1.27 mm thick aluminum plate. The DOS image demonstrates the ability to measure the properties of each generated ultrasonic modes and provides a direct, non destructive, measure of elastic moduli of the tested specimensComment: Laser ultrasonics, Fourier transformation, NDT&E, Lamb waves, plate mode

    Stabilization of polymer colloid dispersions with pH-sensitive poly-acrylic acid brushes

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    Polyelectrolyte brushes are widely used for surface modification of nano-and colloidal particles because of their ability to dramatically change their conformation, hydrophobicity, polarity, charge, etc., as a response to smooth variations in environmental conditions. In this work, we have studied experimentally the stability behavior of polymer colloids with grafted poly-acrylic acid (PAA) surface brushes. We have measured the Fuchs stability ratio (W) as a function of electrolyte concentrations at different pH. It is observed that at pH  8), since most of the carboxylic groups are ionized, the colloidal stability is much higher than that at pH ~ 5. However, the W values are basically the same with 1% and 2% PAA, implying that the contribution of the ionized AA in the two cases is practically the same. This experimental evidence indicates that only the ionized AA groups in the outer region of long brushes contribute to colloidal stability, thus supporting the hypothesis of local electroneutrality in the inner region of long brushes (LEA

    A Bi-Objective Fuzzy Credibilistic Chance-Constrained Programming Approach for the Hazardous Materials Road-Rail Multimodal Routing Problem under Uncertainty and Sustainability

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    Hazardous materials transportation involves extensive risk and cannot be avoided in practice. An advanced routing, however, can help to reduce the risk by planning the best transportation routes for hazardous materials that can make effective tradeoffs between the risk objective and the economic objective. In this study, we explore the hazardous materials routing problem in the road-rail multimodal transportation network with a hub-and-spoke structure, in which the risk is measured by the multiplication of population exposure and the associated volume of hazardous materials, and minimizing the total risk of all the transportation orders of hazardous materials is set as the risk objective. It is difficult to estimate the population exposure exactly during the routing decision-making process, which results in its uncertainty. In this study, we formulate the uncertain population exposure from a fuzzy programming perspective by using triangular fuzzy numbers. Moreover, the carbon dioxide emission constraint is formulated to realize the sustainable transportation of hazardous materials. To optimize the problem under the above framework, we first establish a bi-objective fuzzy mixed integer nonlinear programming model, and then develop a three-stage exact solution strategy that the combines fuzzy credibilistic chance constraint, linearization technique, and the normalized weighting method. Finally, a computational experiment is carried out to verify the feasibility of the proposed method in dealing with the problem. The experimental results indicate that tradeoffs between the two conflicting objectives can be effectively made by using the Pareto frontier to the hazardous materials routing problem. Furthermore, the credibility level and carbon dioxide emission cap significantly influence the hazardous materials routing optimization. Their effects on the optimization result are quantified by using sensitivity analysis, which can draw some useful insights to help decision makers to better organize the hazardous materials road-rail multimodal transportation under uncertainty and sustainability. Document type: Articl
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