Optimal Design of Concrete Canal Section for Minimizing Costs of Water Loss,Lining and Earthworks

Canal section design with minimum cost, which can be considered as an objective function, involves minimization of total costs per unit length of the canal, including direct costs of per cubic meter earthworks and per meter canal lining and indirect costs of water losses through canal seepage and evaporation. Since the costs (both direct and indirect) are associated with the canal geometry and dimensions, it is possible to lower them by optimization of the mentioned objective function. For this purpose, some constraints were subjected and considered to solve the problem. Flow discharge, as the main constraint, was considered in addition to the minimum permissible velocity and Froude’s number, as subsidiary constraints. MATLAB programming software was used to demonstrate and run the optimization algorithm. The results finally were illustrated in forms of dimensionless graphs, which simplify the optimum design of canal dimensions with minimum cost per meter length. Comparing the results with other similar studies, however show the importance and role of earthworks and lining costs, as well as including the subsidiary constraints in the optimization process.     

A survey of shaped-based registration and segmentation techniques for cardiac images

Heart disease is the leading cause of death in the modern world. Cardiac imaging is routinely applied for assessment and diagnosis of cardiac diseases. Computerized image analysis methods are now widely applied to cardiac segmentation and registration in order to extract the anatomy and contractile function of the heart. The vast number of recent papers on this topic point to the need for an up to date survey in order to summarize and classify the published literature. This paper presents a survey of shape modeling applications to cardiac image analysis from MRI, CT, echocardiography, PET, and SPECT and aims to (1) introduce new methodologies in this field, (2) classify major contributions in image-based cardiac modeling, (3) provide a tutorial to beginners to initiate their own studies, and (4) introduce the major challenges of registration and segmentation and provide practical examples. The techniques surveyed include statistical models, deformable models/level sets, biophysical models, and non-rigid registration using basis functions. About 130 journal articles are categorized based on methodology, output, imaging system, modality, and validations. The advantages and disadvantages of the registration and validation techniques are discussed as appropriate in each section.     

Effect of Hydrogen Free Radicals on Hg<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>Cd<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Te

The effects of atomic hydrogen (H) and Br/methanol etching on Hg_1−x Cd _x Te films were investigated using x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Exposure of an as-received Hg_1−x Cd _x Te sample to H + H₂ resulted in H-induced TeO₂ reduction. The oxide reduction was first order with respect to H + H₂ exposure. Exposure to H + H₂ after etching the Hg_1−x Cd _x Te film in a Br/methanol solution induced Hg and C depletion. Hg and C removal was also observed after completely reducing the TeO₂ on the as-received sample. The removal process was hindered by the formation of a Cd-rich overlayer on both etched and unetched surfaces.     

Pseudohalogenation of methyl 9-hydroxy-cis-12-and 12-hydroxy-cis-9-octadecenoate

Pseudohalogenation of methyl 9-hydroxy-cis-12-octadecenoate (I) and methyl 12-hydroxy-cis-9-octadecenoate (II) has been carried out with N,N-dibromobenzenesulfonamide (NNDBS). Compounds I and II, on reaction with NNDBS, formed four and three products, respectively. The interesting feature of these reactions was the formation of 1,4-epoxy compounds. The structures of individual compounds were established with the help of elemental and spectral analysis.     

Surface Characterization of Mild Steel During Atmospheric Corrosion After Being Treated by Sodium Dihydrogen Orthophosphate

Protection of Metals and Physical Chemistry of Surfaces - The objective of this study was to characterize the surfaces of the steel products produced locally during their exposure to the industrial...     

DOLOMITIZATION AND ANHYDRITE PRECIPITATION IN PERMO-TRIASSIC CARBONATES AT THE SOUTH PARS GASFIELD, OFFSHORE IRAN: CONTROLS ON RESERVOIR QUALITY

Dolomitization and related anhydrite cementation can complicate the characterization of carbonate reservoirs. Both processes have affected the Permo-Triassic Upper Dalan – Kangan carbonates, the main reservoir at the South Pars gasfield, offshore Iran. The carbonates were deposited in a shallow-marine ramp or epeiric platform and, according to previous studies, underwent intense near-surface diagenesis and minor burial modification. Detailed petrographical and geochemical analyses indicate that dolomitization and anhydrite precipitation can be explained in terms of the sabkha/seepage-reflux models. The early dolomites then re-equilibrated or re-crystallized in a shallow burial setting. Evaluation of poroperm values in different reservoir intervals indicates that replacive dolomitization in the absence of anhydrite precipitation or with only patchy anhydrite has enhanced the reservoir quality. Where anhydrite cement is pervasive and has plugged the rock fabric, poroperm values are significantly decreased. As emphasized in previous studies and confirmed here, dolomitization and anhydrite cementation, together with original facies type, are the major factors controlling reservoir quality in the Dalan – Kangan carbonates at South Pars. When associated with minor anhydrite cementation, replacive dolomitization has enhanced reservoir quality by increasing permeability. However, porosity in fabric-retentive dolomite was apparently inherited from the precursor rock and therefore reflects the original depositional environment. Low-temperature dolomitization is commonly fabric-selective and partially fabric-retentive. Whole rock stable isotope thermometry indicates that fabric-destructive dolomites in the reservoir rocks formed at temperatures above 22°C, whereas fabric-retentive dolomites and associated anhydrites formed in surface and near-surface conditions. Fabric-destructive dolomite or dolomite neomorphism post-date fabric-retentive dolomite and continued to form in deep burial conditions (∼1400m). These observations may explain why fabric-retentive dolomite and anhydrite fabrics are traversed by stylolites.     

Shielding effectiveness of a rectangular enclosure with finite wall thickness and rectangular apertures by the generalised modal method of moments

An efficient and accurate technique based on modal method of moments (MoM) is introduced, which takes into account the perforated wall thickness in the calculation of the shielding effectiveness (SE) of a rectangular enclosure. To achieve this, the modal expansion of the magnetic currents at both sides of the aperture is considered and the volume inside the aperture and the enclosure walls is represented by a proper Green's function that is incorporated in the original modal MoM. The SE of an enclosure with single and multiple rectangular apertures with various wall thicknesses is examined. A very good agreement among the results of the proposed method and experimental results is observed. It is shown that wall thickness affects the calculated SE, and hence, the accuracy and precision of SE prediction is increased by taking it into consideration. In addition to being efficient, the method shows convergent results even for very small thicknesses.     

Continuum and atomistic modeling of electromechanically-induced failure of ductile metallic thin films

A multiscale modeling approach is presented for the analysis of electromechanically-induced void morphological evolution and failure in ductile metallic thin films, which are used for device interconnections in integrated circuits. Self-consistent mesoscopic simulations of surface morphological evolution are combined with atomistic calculations of surface properties and molecular-dynamics (MD) simulations of plastic deformation mechanisms in the vicinity of void surfaces. Results are presented that demonstrate a coupled mode of surface instability that leads to formation of electromigration-induced slit-like features and stress-induced crack-like features on void surfaces. In addition, MD results are presented for the dislocation-mediated mechanism and the kinetics of void growth in ductile metallic systems subject to hydrostatic and biaxial tensile strains. The incorporation of MD-derived constitutive information for plastic deformation into the mesoscopic analysis and simulation framework also is discussed.     

Theoretical Studies of the Output Pulse with Variation of the Pumping Pulse for RF Excited CO2 Pulsed Waveguide Laser

The behavior of a RF-excited waveguide CO2 laser in the pulse regime is studied theoretically. The output pulse evolution is studied by applying three types of pulses namely the square, sine and the triangular ones as the excitation pulses. The frequency dependence behavior of the output pulse is also presented.