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Many Other Applications (many + other_application)
Selected AbstractsCover Picture: Electrophoresis 7'09ELECTROPHORESIS, Issue 10 2009Article first published online: 13 MAY 200 Issue no. 10 is a special issue on CE-MS edited by Phillipe Schmitt-Kopplin. It has three review articles describing recent advances in fundamental concepts, instrumentation, food safety, food quality, trace analysis of environmental pollutants and food contaminants, as well as many other applications. In addition, the special issue consists of 22 research articles on various topics of CE-MS, including technical and method developments, residue analysis in food and environmental applications and applications in diagnostic and life sciences. [source] A low-leakage sample plug injection scheme for crossform microfluidic capillary electrophoresis devices incorporating a restricted cross-channel intersectionELECTROPHORESIS, Issue 15 2008Chin-Lung Chang Abstract This study develops a crossform CE microfluidic device in which a single-circular barrier or a double-circular barrier is introduced at the cross-channel intersection. Utilizing a conventional crossform injection scheme, it is shown that these barriers reduce sample leakage and deliver a compact sample band into the separation channel, thereby ensuring an enhanced detection performance. A series of numerical and experimental investigations are performed to investigate the effects of the barrier type and the barrier ratio on the flow streamlines within the microchannel and to clarify their respective effects on the sample leakage ratio and sample plug variance during the injection process. The results indicate that a single-circular barrier injector with a barrier ratio greater than 20% and a double-circular barrier injector with a barrier ratio greater than 40% minimize the sample leakage ratio and produce a compact sample plug. As a result, both injectors have an excellent potential for use in high-quality, high-throughput chemical analysis procedures and in many other applications throughout the micro-total analysis systems field. [source] High-resolution DNA separation in microcapillary electrophoresis chips utilizing double-L injection techniquesELECTROPHORESIS, Issue 21-22 2004Lung-Ming Fu Abstract An experimental and numerical investigation into the use of high-resolution injection techniques to separate DNA fragments within electrophoresis microchips is presented. The principal material transport mechanisms of electrokinetic migration, fluid flow, and diffusion are considered, and several variable-volume injection methods are discussed. A detailed analysis is provided of a double-L injection technique, which employs appropriate electrokinetic manipulations to reduce sample leakage within the microchip. The leakage effect in electroosmotic flow (EOF) is investigated using a sample composed of rhodamine B and Cy3 dye. Meanwhile, the effects of sample leakage in capillary electrophoresis (CE) separation are studied by considering the separation of 100-base pairs (bp) DNA ladders and HaeIII-digested ,X-174 DNA samples. The present experimental and simulation results indicate that the unique injection system employed in the current microfluidic chip has the ability to replicate the functions of both the conventional cross-channel and the shift-channel injection systems. Furthermore, applying the double-L injection method to these two injection systems is shown to reduce sample leakage significantly. The proposed microfluidic chip and double-L injection technique developed in this study have an exciting potential for use in high-resolution, high-throughput biochemical analysis applications and in many other applications throughout the micrototal analysis systems field. [source] Exact transformation of a wide variety of domain integrals into boundary integrals in boundary element methodINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2008M. R. Hematiyan Abstract In this paper, a sufficient condition for transforming domain integrals into boundary integral is described. The transformation is accomplished by Green's and Gauss' theorems. It is shown that a wide range of domain integrals including some integrals in boundary element method satisfy this sufficient condition and can be simply transformed into boundary. Although emphasis is made on potential and elastostatic problems, this method can also be used for many other applications. Using the present method, a wide range of 2D and 3D domain integrals over simply or multiply connected regions can be transformed exactly into the boundary. The resultant boundary integrals are numerically evaluated using an adaptive version of the Simpson integration method. Several examples are provided to show the efficiency and accuracy of the present method. Copyright © 2007 John Wiley & Sons, Ltd. [source] Generalization of rank reduction problems with Wedderburn's formulaJOURNAL OF CHEMOMETRICS, Issue 11 2003Joan Ferré Abstract In first- and second-order calibration methods based on spectroscopic data, the calculation of the space spanned by the spectra of the interferences has been an important research subject for, among many other applications, calculating the net analyte signal and obtaining figures of merit. Recently, many different calculation methods have been introduced. We show that the calculation of this space can be interpreted from a unified point of view, namely from the rank-one downdating Wedderburn formula. This formula enables one to better understand the properties of the calculation methods currently available. A number of recently introduced signal-preprocessing methods also fit into the proposed framework. Copyright © 2004 John Wiley & Sons, Ltd. [source] Birds after dark: an efficient and inexpensive system for making long-range observations at nightJOURNAL OF FIELD ORNITHOLOGY, Issue 3 2008Carlos D. Santos ABSTRACT The ability of investigators to study the behavior of animals at night is often limited by the difficulties of making observations in the dark, particularly at a distance. Indirect techniques, such as radio tracking, generally produce limited behavioral data, and most night-viewing equipment tends to be both inefficient for making long-range observations and expensive. We describe a long-range night-vision system consisting of a camcorder and infrared laser illuminators. We tested the performance of this system by comparing our ability to quantify the foraging behavior of shorebirds during the day and at night. Distance thresholds for detecting ingestion of prey and for identifying them were similar during the day and night for all species. At night, we were able to quantify all foraging parameters for all species at distances up to 59 m, and to count pecks and steps at distances greater than 200 m for some species. The observation system we describe can be further improved by using camcorders with higher optical zooms or more powerful infrared laser illuminators. Because of its efficiency and relatively low cost, this system has the potential for being useful in many other applications that require long-range observations of animals at night. SINOPSIS La habilidad de los investigadores para estudiar el comportamiento nocturno de los animales es frecuentemente limitada por las dificultades de realizar observaciones en la oscuridad, particularmente a largas distancias. Los métodos indirectos como la radio telemetría generalmente producen datos limitados en cuanto al comportamiento y la mayor parte de los equipos para realizar observaciones nocturnas tienden a ser caros e ineficientes para realizar observaciones a larga distancia. Describimos un sistema para realizar observaciones nocturnas a larga-distancia cual consiste de una videocámara e iluminadores de láser infrarrojos. Probamos este sistema mediante una comparación de nuestra habilidad de cuantificar el comportamiento de forrajeo de aves playeras durante el día y durante la noche. Los umbrales para detectar el consumo de presas y para la identificación de las mismas fueron similares durante el día y durante la noche para todas las especies. Durante la noche pudimos cuantificar todos los parámetros de forrajeo para todas las especies hasta una distancia de 59 m y para algunas especies pudimos contar los picotazos y pasos de las aves a distancias mayores de 200 m. El sistema de observación que describimos puede ser mejorado mediante el uso de videocámaras con zoom ópticos más potentes o con iluminadores de láser infrarrojo más potentes. Por su eficiencia y su costo relativamente bajo, este sistema tiene el potencial de ser útil en varias otras aplicaciones que requieren observaciones nocturnas de animales a larga distancia. [source] An integer programming model for the weekly tour scheduling problemNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 7 2001Tolga Çezik Abstract We study a workforce planning and scheduling problem in which weekly tours of agents must be designed. Our motivation for this study comes from a call center application where agents serve customers in response to incoming phone calls. Similar to many other applications in the services industry, the demand for service in call centers varies significantly within a day and among days of the week. In our model, a weekly tour of an agent consists of five daily shifts and two days off, where daily shifts within a tour may be different from each other. The starting times of any two consecutive shifts, however, may not differ by more than a specified bound. Furthermore, a tour must also satisfy constraints regarding the days off, for example, it may be required that one of the days off is on a weekend day. The objective is to determine a collection of weekly tours that satisfy the demand for agents' services, while minimizing the total labor cost of the workforce. We describe an integer programming model where a weekly tour is obtained by combining seven daily shift scheduling models and days-off constraints in a network flow framework. The model is flexible and can accommodate different daily models with varying levels of detail. It readily handles different days-off rules and constraints regarding start time differentials in consecutive days. Computational results are also presented. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 607,624, 2001. [source] Synthesis, characterization and properties of azobenzene side-chain polythiophene,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 3-5 2003Leong Huat Gan Abstract Thiophene monomers with an azobenzene moiety of different spacer length at the 3-position of the thiophene ring were synthesized. The monomers were polymerized and copolymerized with 3-hexyl thiophene to investigate the influence of an azobenzene side-chain on the properties of polythiophene, which has been widely used as a conducting polymer and has also been found many other applications. The polymers were characterized with UV-vis, FT-IR spectrophotometry, gel permeation chromatographic (GPC) analysis, DSC, TGA, elemental analysis and X-ray diffractometry. The polymers showed novel thermochromic and photoresponsive properties in polymer solutions and solid films. It was found that an azobenzene side-chain could bring about substantial thermochromic and photochromic changes to the polythiophene backbone as compared with non-azobenzene side-chain polythiophenes. These property changes could be triggered or controlled by light or heat on the basis of azobenzene trans,cis or cis,trans isomerization. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||