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MATLAB
Selected AbstractsTeaching differential equations in different environments: A first approachCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 3 2010Filipa Carneiro Abstract The use of specific softwares was the basis for a new approach for teaching ordinary and partial differential equations, in the field of heat transfer and fluid mechanics. The main objective was to enhance learning effectiveness of Numerical Methods in the post-graduate course of Polymers Engineering at the University of Minho. This degree takes place into two different environments: at the university campus and at the industrial field. Different commercial codes were used, namely EXCEL, MATLAB, and FLUENT, as well as two tools developed in house at University of Minho: CoNum and a graphics application PDE v.1. Lectures were based on videoconferencing and other web utilities. The teaching methodology presented and discussed in this article was well received and accepted by the post-graduate students, motivating teachers to improve their teaching/learning strategies. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 555,562, 2010; View this article online at wileyonlinelibrary.com; DOI 10.1002/cae.20231 [source] BONDSYM: SIMULINK-based educational software for analysis of dynamic systemCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 2 2010J.A. Calvo Abstract This article presents an educational software called BONDSYM developed to allow engineering students to learn easily and quickly about the analysis of dynamic systems through the Bond Graph method. This software uses the SIMULINK library of MATLAB, which has proven to be an excellent choice in order to implement and solve the dynamic equations involved. The application allows for the representation of the behavior of a dynamic system analyzed through the Bond Graph theory in order to understand the dynamic equations and the physical phenomena involved. Based on block diagram of SIMULINK, the different "bonds" of Bond Graph can be integrated as SIMULINK blocks in order to generate the dynamic model. A few simple models are analyzed through this application. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 238,251, 2010; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20246 [source] Investigating static and dynamic characteristics of electromechanical actuators (EMA) with MATLAB GUIsCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 2 2010Gursel Sefkat Abstract This paper deals with the design of an electromechanical device considering some prescribed performance requirements, and static and dynamic analysis of this device are carried out. In studying the transient response of such a system, as part of dynamic analysis, two methods mostly used finite element method (FEM) and finite differences method (FDM). However, these methods need much CPU time. In this work, a computer simulator program is developed for an EMA. This technique is implemented in the MATLAB-Simulink environment and tested for different design tasks such as electromagnetic valves or electromechanical brakes etc. Furthermore, by using GUIDE tools within MATLAB, a simple useful and user-friendly GUI structure is developed to provide a visual approach to design and analysis process. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 383,396, 2010; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20279 [source] SIMPERF: SIMULINK-based educational software for vehicle's performance estimationCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 2 2009J. A. Calvo Abstract This paper presents an educational software called SIMPERF developed to allow the engineering students to learn easily and quickly about the vehicle's performance calculations. This software uses the SIMULINK library of MATLAB which has shown to be a good choice to implement and solve the implicated equations. The model allows us to achieve the vehicle's performances with enough accuracy and to modify the parameters than influence on these performances quickly and easily in order to understand the physic phenomena involved. © 2008 Wiley Periodicals, Inc. Comput Appl Eng Educ 17: 139,147, 2009; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae20191 [source] MATLAB as an introductory programming languageCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 1 2006M. A. Wirth Abstract This paper explores the use of MATLAB for teaching the fundamental constructs of programming languages to engineering and science students. It was found that the time taken for students to learn programming can be reduced by up to 50%, paving the way for using the language to solve problems. © 2006 Wiley Periodicals, Inc. Comput Appl Eng Educ 14: 20,30, 2006; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20064 [source] MATLAB based GUIs for linear controller design via convex optimizationCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 1 2003Wathanyoo Khaisongkram Abstract Owing to the current evolution of computational tools, a complicated parameter optimization problem could be effectively solved by a computer. In this paper, a CAD tool for multi-objective controller design based on MATLAB program is developed. In addition, we construct simple GUIs (using GUIDE tools within MATLAB) to provide a visual approach in specifying the constraints. The linear controller design problem can be cast as the convex optimization subjected to time domain and frequency domain constraints. This optimization problem is efficiently solved within a finite dimensional subspace by a practical ellipsoid algorithm. In the design process, we include a model reduction of the resulting controller to speed up the computational efficiency. Finally, a numerical example shows the capability of the program to design multi-objective controller for a one-link flexible robot arm. © 2003 Wiley Periodicals, Inc. Comput Appl Eng Educ 11: 13,24, 2003; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.10035 [source] Environment for engineering design, analysis, and simulation for education using MATLAB via the World Wide Web.COMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 3 2002Abstract In Part II of this paper, we present representative examples that demonstrate the capabilities and features of the developed education environment that allows one to simulate in real time engineering systems utilizing the power of MATLAB through a web browser interface. The web-based graphical user interface (GUI) provides the means for the user to input system parameters and the display of the analysis results. The examples presented demonstrate the required clarity of the developed GUI, and the nature and type of the results returned to the web browser of the user in real time. This environment has the capability to return to the user textual, graphical, pictorial, and animation related material. The user has the option to download analysis results in any of the generated forms to the client computer. This work demonstrates the ease of implementation and advantages of using this technology to aid in classroom instruction. Users with Internet can access the developed simulation modules at http://zodhia.uta.edu/development. © 2002 Wiley Periodicals, Inc. Comput Appl Eng Educ 10: 109,120, 2002; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.10019 [source] Local control of photovoltaic distributed generation for voltage regulation in LV distribution networks and simulation toolsEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 6 2009Stefania Conti Abstract The increasing connection of distributed generation (DG) in distribution networks may affect the quality of power offered to customers. One of the most relevant issues is the possibility to have unacceptable voltage rise at the point of common coupling (PCC). This work focuses on the problem of voltage control in LV distribution networks in the presence of photovoltaic (PV) DG. The paper presents a local voltage control method based on PV generation curtailment as an alternative to ,on/off' operation, typically required by distribution operators to prevent overvoltage at the PCCs by means of overvoltage protections embedded in the PV unit. To show the effect of the proposed local voltage control, a simulation tool, developed in MATLAB®,Simulink® environment, is presented. Appropriate numerical models for network components and PV generators are provided in order to describe computer simulation implementation of the test system. The final results show that the control system is able to adjust the active power output of local generators to keep the voltage profile of the feeder, in which DG is installed, within the range allowed by Norm EN 50160. Copyright © 2008 John Wiley & Sons, Ltd. [source] Strategies for fault classification in transmission lines, using learning vector quantization neural networksEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 4 2006A. J. Mazón Abstract This paper analyses different approaches to fault classification, in two-terminal overhead transmission lines, using learning vector quantization (LVQ) neural networks, just verifying its efficiency. The objective is to classify the fault using the fundamental components of 50/60,Hz of fault and pre-fault voltage and current magnitudes. These magnitudes are measured in each phase at the reference end. The accuracy of these methods has been checked using properly validated fault simulation software developed with MATLAB. This software allows simulating faults in any location of the line, to obtain the fault and prefault voltage and current values. With these values, the fault can be classified. Copyright © 2006 John Wiley & Sons, Ltd. [source] A geometric and kinematic model for double-edge propagating thrusts involving hangingwall and footwall folding.GEOLOGICAL JOURNAL, Issue 5-6 2010An example from the Jaca, Pamplona Basin (Southern Pyrenees) Abstract A new geometric and kinematic model is proposed for a particular type of fault-related folding based on the study of a natural example developed in Palaeogene carbonate rocks from the Jaca,Pamplona Basin (Southern Pyrenees). The example consists of a hangingwall anticline related to a reverse fault with variable displacement and a gentle footwall syncline. A detailed structural analysis of the structure and a cross-section, perpendicular to its axis and parallel to the transport direction, reveals that none of the previous published models of fault-related folds is able to simulate its main characteristics and reproduce its geometry. The main features of the new model are: double-edge propagating fault and folding developed in both the hangingwall and the footwall. A MATLAB-based program was created to calculate structural parameters such as shortening, structural relief and fault slip; obtain graphs of different parameters such as shortening versus slip along the fault, shortening versus fault length, and produce sections across forward models showing the different stages of fold growth. The model presented here gives an acceptable geometrical fit to the studied natural structure and provides a reasonable evolutionary history. In addition, the results obtained using the model are similar to those measured on the cross-section. As a final step the subsurface portion of the natural fold was completed following the constraints imposed by the model. Copyright © 2010 John Wiley & Sons, Ltd. [source] Estimating Aquifer Transmissivity from Specific Capacity Using MATLABGROUND WATER, Issue 4 2005Stephen G. McLin Historically, specific capacity information has been used to calculate aquifer transmissivity when pumping test data are unavailable. This paper presents a simple computer program written in the MATLAB programming language that estimates transmissivity from specific capacity data while correcting for aquifer partial penetration and well efficiency. The program graphically plots transmissivity as a function of these factors so that the user can visually estimate their relative importance in a particular application. The program is compatible with any computer operating system running MATLAB, including Windows, Macintosh OS, Linux, and Unix. Two simple examples illustrate program usage. [source] Study on the action of the active earth pressure by variational limit equilibrium methodINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 10 2010Li Xinggao Abstract Within the framework of limiting equilibrium approach, the problem of active earth pressure on rigid retaining wall is formulated in terms of the calculus of variations by means of Lagrange multipliers. It is transcribed as the functional of extreme-value problem by two undetermined function arguments, and is further transformed into determining the minimax solution of restrained functions incorporating the geometrical relations of the problem. The function of (fmincon) in the optimization toolbox of MATLAB 6.1 can be used to find the minimax solution. Computation results show there exist two kinds of modes of failure sliding along plane surface and rotating around log-spiral cylinder surface when the soil behind the walls reaches the critical active state. The magnitude of active earth pressure in the case of translational mode is less than that in the case of rotational mode. The location of action point of earth pressure in the case of translational mode is at or below height of the wall, and in the case of rotational mode, is above height of the wall. Preliminary study indicates a pair of numbers by two theoretical modes can be regarded as an interval estimation of active pressure. Copyright © 2009 John Wiley & Sons, Ltd. [source] Numerical stability of unsteady stream-function vorticity calculationsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 6 2003E. Sousa Abstract The stability of a numerical solution of the Navier,Stokes equations is usually approached by con- sidering the numerical stability of a discretized advection,diffusion equation for either a velocity component, or in the case of two-dimensional flow, the vorticity. Stability restrictions for discretized advection,diffusion equations are a very serious constraint, particularly when a mesh is refined in an explicit scheme, so an accurate understanding of the numerical stability of a discretization procedure is often of equal or greater practical importance than concerns with accuracy. The stream-function vorticity formulation provides two equations, one an advection,diffusion equation for vorticity and the other a Poisson equation between the vorticity and the stream-function. These two equations are usually not coupled when considering numerical stability. The relation between the stream-function and the vorticity is linear and so has, in principle, an exact inverse. This allows an algebraic method to link the interior and the boundary vorticity into a single iteration scheme. In this work, we derive a global time-iteration matrix for the combined system. When applied to a model problem, this matrix formulation shows differences between the numerical stability of the full system equations and that of the discretized advection,diffusion equation alone. It also gives an indication of how the wall vorticity discretization affects stability. Despite the added algebraic complexity, it is straightforward to use MATLAB to carry out all the matrix operations. Copyright © 2003 John Wiley & Sons, Ltd. [source] On stochastic modelling of linear circuitsINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 3 2010Tarun Kumar Rawat Abstract In this paper, the deterministic modelling of linear circuits is replaced by stochastic modelling by including variance in the parameters (resistance, inductance and capacitance). Our method is based on results from the theory of stochastic differential equations. This method is general in the following sense. Any electrical circuit that consists of resistances, inductances and capacitances can be modelled by ordinary differential equations, in which the parameters of the differential operators are the functions of circuit elements. The deterministic ordinary differential equation can be converted into a stochastic differential equation by adding noise to the input potential source and to the circuit elements. The noise added in the potential source is assumed to be a white noise and that added in the parameters is assumed to be a correlated process because these parameters change very slowly with time and hence must be modelled as a correlated process. In this paper, we model a series RLC circuit by using the proposed method. The stochastic differential equation that describes the concentration of charge in the capacitor of a series RLC circuit is solved. Numerical simulations in MATLAB are obtained using the Euler,Maruyama method. Copyright © 2008 John Wiley & Sons, Ltd. [source] Global hybrid modeling and control of a buck converter: A novel conceptINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 9 2009Mohammad Hejri Abstract Several attempts have been made to design suitable controllers for DC,DC converters. However, these designs suffer from model inaccuracy or their inability to desirably function in both continuous and discontinuous current modes. This paper presents a novel switching scheme based on hybrid modeling to control a buck converter using mixed logical dynamical (MLD) methodologies. The proposed method is capable of globally controlling the converter in both continuous and discontinuous current modes of operation by considering all constraints in the physical plant such as maximum inductor current and capacitor voltage limits. Different loads and input voltage disturbances are simulated in MATLAB and results are presented to demonstrate the suitability of the controller. The transient and steady-state performance of the closed-loop control over a wide range of operating points shows satisfactory operation of the proposed controller. Copyright © 2008 John Wiley & Sons, Ltd. [source] Small-signal analysis of interleaved dual boost converterINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 6 2001Mummadi Veerachary Abstract This paper presents a systematic development of steady-state, small-signal models of interleaved dual boost converter operating in a continuous current mode. These models are derived by employing the well-known signal flow graph method. This signal flow graph approach provides a means to directly translate the switching converter into its equivalent graphic model, from which a complete behaviour of the converter can easily be studied. Steady-state performance, small-signal characteristic transfer functions are derived using Mason's gain formula. The bode plots of audiosusceptibility, input impedance, output impedance, and control-to-output transfer functions are determined and illustrated using MATLAB for different values of load resistances, duty ratios. Small-signal frequency responses obtained from the signal flow graph method are validated with PSPICE simulator results. To validate the signal flow graph modelling equations, sample steady-state experimental results are provided. Copyright © 2001 John Wiley & Sons, Ltd. [source] A novel fair random access scheme with throughput optimization using fuzzy controller for wireless systemsINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 4 2009M. R. M. Rizk Good backoff algorithms should be able to achieve high channel throughput while maintaining fairness among active nodes. In this paper, we propose a novel backoff algorithm to improve the fairness of random access channels, while maximizing channel throughput. The mechanism of the proposed backoff algorithm uses backoff delay (retransmission delay) and channel-offered traffic to dynamically control the backoff interval, so that each active node increases its backoff interval in the case of collision by a factor which exponentially decreases as the backoff delay increases, and decreases its backoff interval in the case of successful transmission by a factor which exponentially decreases as the backoff delay of previous retransmission attempts increases. Also, the backoff interval is controlled according to the channel offered, traffic using a fuzzy controller to maximize channel throughput. Furthermore, the operation of the proposed backoff algorithm does not depend on knowledge of the number of active nodes. A computer simulation is developed using MATLAB to evaluate the performance of the proposed backoff algorithm and compare it with the binary exponential backoff (BEB) scheme, which is widely used owing to its high channel throughput, while its fairness is relatively poor. It is shown that the proposed backoff algorithm significantly outperforms the BEB scheme in terms of improving the performance of fairness, and converges to the ideal performance as the minimum backoff interval increases, while achieving high channel throughput. Copyright © 2008 John Wiley & Sons, Ltd. [source] Kinetic and dynamic study of liquid,liquid extraction of copper in a HFMC: Experimentation, modeling, and simulationAICHE JOURNAL, Issue 6 2010M. Younas Abstract In this work, we present the dispersion-free liquid,liquid extraction of copper from aqueous streams in a hollow fiber membrane contactor (HFMC). Copper has been transferred from aqueous solutions to heptane using LIX 84-I (2-hydroxy-5-nonylacetephenone oxime) as extracting agent. In a first step, batch experiments have been performed to identify the extraction kinetics and to measure the partition coefficient of copper aqueous-organic phase system. Then, the continuous recycled-base extraction process has been performed in a HFMC Liqui-Cel® module. The module has been modeled from resistance in series concept to gain the exit concentrations, which are used to develop a dynamic model to calculate the exit concentration of copper from the output of storage tanks. The model has been validated with experimental data at various operating conditions. The integrated process model algorithm was scripted in MATLAB® 7.4 R (a). Simulations have been made for a range of different operating parameters to determine the optimum criterion conditions. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Computational Statistics Handbook with MATLABJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 4 2009Varinder Jain No abstract is available for this article. [source] Optimization of carbon black and nanoclay filler loading in chlorobutyl vulcanizates using response surface methodologyPOLYMER COMPOSITES, Issue 6 2009V. Sridhar In this article, an attempt has been made to study the applicability of using organo nanoclay (Cloisite 30B) and carbon black (HAF, N330) in chlorinated isobutyl isoprene rubber vulcanizates. Statistical design of experimentation was adopted so that maximum information can be obtained from a minimum number of experiments. Response surface methodology was applied successfully to rubber compound design using a rotatable central compound design. Compounding trials were carried out at design points, and the rubber vulcanizates were characterized for modulus, tensile strength, elongation at break, tear strength, bound rubber, and free volume parameters ,3 and I3. The experimental data was used to generate mathematical models by multiple linear regression analysis using MATLAB (version 6) package. The variability of the postulated models was tested by analysis of variance (ANOVA) and R2 tests and was found to be adequate. The accuracy of the models generated was tested by making an experimental trial. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers [source] Verified global optimization with GloptLabPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2007Ferenc Domes GloptLab is a testing and development platform for solving quadratic constraint satisfaction problems, written in MATLAB. All applied methods are rigorous, hence it is guaranteed that no feasible point is lost. Some emphasis is given to finding a bounded initial box containing all feasible points, in cases where other complete solvers rely on non-rigorous heuristics. The algorithms implemented in GloptLab are used to reduce the search space: scaling, constraint propagation, linear relaxations, strictly convex enclosures, conic methods, and branch and bound. From the method repertoire custom made strategies can be built, with a user friendly graphical interface. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A toolkit for the characterization of CCD cameras for transmission electron microscopyACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2010M. Vulovic Charge-coupled devices (CCD) are nowadays commonly utilized in transmission electron microscopy (TEM) for applications in life sciences. Direct access to digitized images has revolutionized the use of electron microscopy, sparking developments such as automated collection of tomographic data, focal series, random conical tilt pairs and ultralarge single-particle data sets. Nevertheless, for ultrahigh-resolution work photographic plates are often still preferred. In the ideal case, the quality of the recorded image of a vitrified biological sample would solely be determined by the counting statistics of the limited electron dose the sample can withstand before beam-induced alterations dominate. Unfortunately, the image is degraded by the non-ideal point-spread function of the detector, as a result of a scintillator coupled by fibre optics to a CCD, and the addition of several inherent noise components. Different detector manufacturers provide different types of figures of merit when advertising the quality of their detector. It is hard for most laboratories to verify whether all of the anticipated specifications are met. In this report, a set of algorithms is presented to characterize on-axis slow-scan large-area CCD-based TEM detectors. These tools have been added to a publicly available image-processing toolbox for MATLAB. Three in-house CCD cameras were carefully characterized, yielding, among others, statistics for hot and bad pixels, the modulation transfer function, the conversion factor, the effective gain and the detective quantum efficiency. These statistics will aid data-collection strategy programs and provide prior information for quantitative imaging. The relative performance of the characterized detectors is discussed and a comparison is made with similar detectors that are used in the field of X-ray crystallography. [source] Computational Statistics Handbook with MATLAB®, 2nd edition by MARTINEZ, W. L. and MARTINEZ, A. R.BIOMETRICS, Issue 1 2009Article first published online: 17 MAR 200 No abstract is available for this article. [source] A multikinetic model approach to predict gluconic acid production in an airlift bioreactorBIOTECHNOLOGY JOURNAL, Issue 5 2007Mukesh Mayani Abstract This paper uses a multikinetic approach to predict gluconic acid (GA) production performance in a 4.5 L airlift bioreactor (ALBR). The mathematical model consists of a set of simultaneous firstorder ordinary differential equations obtained from material balances of cell biomass, GA, glucose, and dissolved oxygen. Multikinetic models, namely, logistic and contois equations constitute kinetic part of the main model. The main model also takes into account the hydrodynamic and mass transfer parameters. These equations were solved using ODE solver of MATLAB v6.5 software. The mathematical model was validated with the experimental data available in the literature and is used to predict the effect of change in initial biomass and air sparging rate on the GA production. It is concluded that the mathematical model incorporated with multikinetic approach would be more efficient to predict the change in operating parameters on overall bioprocess of GA production in an ALBR. [source] Electronic Speckle Pattern Interferometry: A Tool for Determining Diffusion and Partition Coefficients for Proteins in GelsBIOTECHNOLOGY PROGRESS, Issue 6 2002David Karlsson The aim of this study was to demonstrate electronic speckle pattern interferometry (ESPI) as a powerful tool in determining diffusion coefficients and partition coefficients for proteins in gels. ESPI employs a CCD camera instead of a holographic plate as in conventional holographic interferometry. This gives the advantage of being able to choose the reference state freely. If a hologram at the reference state is taken and compared to a hologram during the diffusion process, an interferometric picture can be generated that describes the refraction index gradients and thus the concentration gradients in the gel as well as in the liquid. MATLAB is then used to fit Fick's law to the experimental data to obtain the diffusion coefficients in gel and liquid. The partition coefficient is obtained from the same experiment from the flux condition at the interface between gel and liquid. This makes the comparison between the different diffusants more reliable than when the measurements are performed in separate experiments. The diffusion and partitioning coefficients of lysozyme, BSA, and IgG in 4% agarose gel at pH 5.6 and in 0.1 M NaCl have been determined. In the gel the diffusion coefficients were 11.2 ± 1.6, 4.8 ± 0.6, and 3.0 ± 0.3 m2/s for lysozyme, BSA, and IgG, respectively. The partition coefficients were determined to be 0.65 ± 0.04, 0.44 ± 0.06, and 0.51 ± 0.04 for lysozyme, BSA, and IgG, respectively. The current study shows that ESPI is easy to use and gives diffusion coefficients and partition coefficients for proteins with sufficient accuracy from the same experiment. [source] Modeling of Kinetic Expressions for the Reduction of NOx by Hydrogen in Oxygen-Rich Exhausts Using a Gradient-Free Loop ReactorCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2003E. Frank Abstract The reduction of NOx by hydrogen under lean conditions is investigated in a gradient-free loop reactor. Using this computer-controlled reactor, the reaction rates can be measured under exact isothermal conditions. Systematic variation of the input concentrations of hydrogen, nitric oxide, oxygen as well as reaction temperature provides a complete data set of reaction rates for the given reaction system. A number of kinetic rate expressions were evaluated for their ability to fit the experimental data by using toolboxes of MATLAB. The temperature influence on reaction rate constants and adsorption equilibrium constants were correlated simultaneously using Arrhenius and van't Hoff equations, respectively. The kinetic rate expression based on a Langmuir-Hinshelwood-type model describes the data and the model can be improved by introducing a correction term in square root of hydrogen partial pressure over the range of conditions investigated. [source] 4334: Fully automated corneal endothelial morphometry of a large set of images captured by clinical specular microscopyACTA OPHTHALMOLOGICA, Issue 2010C BUCHT Purpose The endothelial cell density is the most important morphological factor of the corneal endothelium. Morphometry of the corneal endothelium is an important part of several clinical applications. Morphometry of the endothelium is presently carried out by semi automated analysis of pictures captured by Clinical Specular Microscopy (CSM). The need of operator involvement makes this process time consuming. This study presents a method for fully automated analysis of a large range of in vivo images of the corneal endothelium, captured by CSM, using Fourier analysis. Methods Software was developed in the mathematical programming language MATLAB. Pictures of the corneal endothelium, captured by CSM, were read into the analysis software. The software performed automated digital enhancement of the images. The enhanced images were Fourier transformed, using the Fast Fourier Transform. Relevant characteristics of the Fourier transformed images were identified and sampled. The data obtained from each transformed image was used to calculate the mean cell density of the original image, which in turn was compared to a semi automated method cell density estimate. The calculation was based on well known diffraction theory. Results Estimated cell densities of the corneal endothelium were obtained, using fully automated analysis software on 292 images captured by CSM. Using linear regression, a relatively large correlation between the estimates of the fully automated method and the semi automated method was found. Conclusion The results using the considerably faster fully automated method are highly encouraging for further development and implementation of the method. [source] Computational Colour Science Using MATLABCOLOR RESEARCH & APPLICATION, Issue 2 2005Rajeev Ramanath No abstract is available for this article. [source] Diploic venous anatomy studied in-vivo by MRICLINICAL ANATOMY, Issue 3 2009Khalil Jivraj Abstract Calvarial diploic venous anatomy has been studied post-mortem, but few studies have addressed these venous structures in-vivo. Previous work in our laboratory has shown that intraosseous infusion through the skull diploic space near the diploic veins in animals and humans does access the superior sagittal sinus and the systemic venous system. We developed a volumetric method of imaging the diploic veins in-vivo using MRI, intravenous gadolinium, and digital subtraction to provide for three-dimensional depiction and exact localization of these veins. We hypothesized that this technique would allow for an assessment of the probability of existence, distribution, and concentration of diploic veins in the skull. We scanned 31 neurosurgical patients, and were able to create 3D diploic venous maps in 74% of them. These maps were processed using Adobe Photoshop CS2. Mathworks MatLab 6.5, once customized, counted the number of pixels occupied by the diploic veins in the processed image. The probability of veins was highest in the occipital regions (100%). The inferior occipital (4.1%) and posterior parietal (4.1%) regions had the highest concentrations of diploic veins. Digital subtraction venography using a volumetric MRI sequence can demonstrate the diploic veins in-vivo. The inferior occipital region may be the best area for an intraosseous infusion device because it has the greatest likelihood of containing a vein and also has the highest concentration of veins. Clin. Anat. 22:296,301, 2009. © 2009 Wiley-Liss, Inc. [source] A graphical generalized implementation of SENSE reconstruction using MatlabCONCEPTS IN MAGNETIC RESONANCE, Issue 3 2010Hammad Omer Abstract Parallel acquisition of Magnetic Resonance Imaging (MRI) has the potential to significantly reduce the scan time. SENSE is one of the many techniques for the reconstruction of parallel MRI images. A generalized algorithm for SENSE reconstruction and theoretical background is presented. This algorithm can be used for SENSE reconstruction for any acceleration factor between 2 and 8, for any Phase Encode direction (Horizontal or Vertical), with or without Regularization. The user can select a particular type of Regularization. A GUI based implementation of the algorithm is also given. Signal-to-noise ratio, artefact power, and g -factor map are used to quantify the quality of reconstruction. The effects of different acceleration factors on these parameters are also discussed. The GUI based implementation of SENSE reconstruction provides an easy selection of various parameters needed for reconstruction of parallel MRI images and helps in an efficient reconstruction and analysis of the quality of reconstruction. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part A 36A: 178,186, 2010. [source] | |||||||||||||||||||||||||