149 research outputs found

    Optimum Depth of Seismic Drains for Mitigating Large Deformations in Liquefied Ground with Hydraulic Barrier

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    Liquefaction of water saturated granular soils is one of the major risks that affect the safety and post-earthquake performance of infrastructure such as bridges, dams, buildings, and lifelines in various parts of the world. The seismically induced ground deformations are often the main concern when liquefaction occurs in significant zones of an earth structure or soil foundation. Recent studies including field data, centrifuge model testing and numerical investigations indicate that large lateral spreads and flow-slides in gentle sandy slopes have taken place when a low permeability silt/clay layer (hydraulic barrier) is present. One of the promising measures to alleviate this barrier effect and ground failures is seismic drains. Currently the effects of seismic drain configuration in plan are well understood and established in the engineering profession. However, most drain improvement schemes comprise of seismic drains that fully penetrate the liquefied soil layer. This paper describes the results of a coupled stress-flow dynamic analysis to investigate the enhancement effect of drain depth on deformations of liquefied slopes with barrier sub-layer. This study showed that drains that fully penetrate the liquefiable depth do not provide the lowest deformations and as a result may not provide the optimum solution

    Efficacy and Safety of Lamotrigine in Lennox - Gastaut Syndrome

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    ObjectiveThe Lennox-Gastaut syndrome (LGS), one of the most difficult epilepsy syndromes to treat, is characterized by a triad of intractable seizures of various types, a slow (< 2.5-hertz) spike-wave pattern in EEG and mental retardation. The aim of this study was to evaluate the efficacy and safety of lamotrigine as add-on therapy in intractable epilepsy of children with LGS.Materials & MethodsIn a quasi- experimental study, 40 children with LGS referred to the pediatric neurology clinic of Shaheed Sadoughi Hospital in Yazd, between August 2007 and to November 2008, were evaluated.ResultsTwenty-two boys and 18 girls with a mean age of 4.12 ±1.8 years were evaluated. At the end of three months of treatment with lamotrigine, 12 % were seizure free, 52% had> 50% reduction in seizure frequency and 12% had increase in seizures. Means of seizure frequency/per week, before and after treatment were 70 (range 1-180) and 18.6 (range 0-60) respectively, indicating effectiveness of the drug in seizure reduction (P value = 0.003). The drug was effective in 72 % of mixed type seizures, 40 % of generalized tonic-clonic and 33% of drop attack and tonic seizures. Transient side effects were seen in 12.5 % (drowsiness in 3 and ataxia in 2 children). No serious side effects were seen.ConclusionLamotrigine should be considered as an add-on therapy in management of intractable epilepsy in LGS

    Classification of visualization exudates fundus images results using support vector machine

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    This paper classifies the characteristics of normal and exudates fundus images by determine its accuracy for diagnostic purposes. Image normalization was performed on 149 fundus images (81 normal and 68 exudates) from MESSIDOR databases to standardize the colours in the fundus images. The OD removed fundus image and fundus image with the exudates areas removed. The SVM1 classifier was applied to 30 test fundus images to determine the best optimal parameter. The kernel function settings; linear, polynomial, quadratic and RBF have an effect on the classification results. For SVM1, the best parameter in classifying pixels is linear kernel function. The visualization results using CAC and radar chart are classified using ts accuracy. It has proven to discriminated exudates and non exudates pixels in fundus image using linear kernel function of SVM1 to diagnose DR.Keywords: Diabetic retinopathy (DR); Optic disc (OD); Support Vector Machine (SVM); AC); Radial Basis Function (RBF)

    Deriving optimal operational policies for off-stream man-made reservoir considering conjunctive use of surface- and groundwater at the Bar dam reservoir (Iran)

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    Study region: The off-stream artificial Bar lake, built in 2015 to store the flood flows of the Bar river for domestic and industrial needs and with the objective to intentionally recharge the aquifer, is situated in the Razavi Khorasan province (Iran). Study focus: We present a methodology, based on the combination of a MODFLOW groundwater flow model for estimating seepage rates, and an optimization model, for the management and operation of an artificial reservoir considering surface/groundwater interactions for satisfying 12 Mm3/year of water demand. We simulated the reliable amount of water that can be supplied from the reservoir, considering reservoir seepage, maximizing water supply yields subject to the water supply reliability requirements, and the additional intentional volume of groundwater recharge. New hydrological insights for the region: Our results demonstrate the reliability of conjunctive use of surface-and ground-water in water scarce areas by exploiting reservoir infrastructures with relevant leakage losses, also for creating additional aquifer storage. In such systems, man-induced changes of lake stages can significantly affect the volume of water that seeps through the lakebed. The aquifer, under managed aquifer recharge operations, may then provide the resource not satisfied by the reservoir release, fulfilling 100 % reliability of water supply. The conjunctive use of surface- and ground-water, by improving water security, may open new sustainability views for leaking reservoirs, even if they were not initially designed for increasing aquifer recharge, in many areas worldwide

    The Effect of the Marketing Mix and Specialized Knowledge on the Export Performance of SMEs Exporting Dry Fruits

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    Export is a crucial driver of economic growth in various countries and significantly contributes to a country's entry into global markets and enhances economic success. In developing countries such as Iran, economic and social development programs prioritize the expansion of exports, particularly high value added agricultural products. The growth in non-oil exports, such as dried fruits, and the entry of domestic producers into new global markets have led to an increased demand for Iran's export products. This has also resulted in higher production levels, increased employment opportunities, and higher value added in the related activities. To enhance export performance, which is a crucial measure of a company's success in utilizing its resources and capabilities in the international arena over a specific period of time, it is important to focus on improving marketing strategies and specialized knowledge. Therefore, this research aims to examine the impact of marketing mix and specialized marketing knowledge on the export performance of small and medium-sized enterprises (SMEs) involved in exporting dried fruits in Mashhad, Iran in 2022. A total of 80 questionnaires were distributed among senior managers, board members, and business managers of dried fruits SMEs using the available sampling method. Structural equation modeling was employed for data analysis and test of research hypotheses. The statistical data and structural equation modeling revealed that the joint impact of marketing mix and specialized marketing knowledge has a positive and significant influence on export performance. In order to improve the company's profitability, it is essential for senior managers and sales managers to recognize the significance of these two factors and undergo relevant training to acquire the necessary skills. Moreover, managers should make effective use of appropriate distribution channels to expand their exports. Simultaneously, they should consider adapting product quality and packaging to align with the preferences of foreign buyers

    Experimental Study of Natural Convective Flow over a Hot Horizontal Rhombus Cylinder Immersed in Water via PIV Technique

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    Natural convective flow over a horizontal cylinder is a phenomenon used in many industries such as heat transfer from an electrical wire, heat exchanger, pipe heat transfer, etc. In this research, fluid dynamics of natural convective flow over a horizontal rhombus cylinder, with uniform heat flux, is investigated by using two-dimensional Particle Image Velocimetry (PIV) Technique. Experiments are carried out in a cubical tank full of water having an interface with air and the cylinder is placed horizontally inside the tank. The heater is turned on for 40s and the effects of heater's power and the height of water above the cylinder are surveyed. The experiments are carried out in three different heights of water and two different heater’s powers in which Rayleigh number changes from 1.33×107 to 1.76×107. The emitted heat flux causes the buoyancy force to be made and the main branch of flow to be formed. Then, moving up the main branch flow through the stationary water generates two equal anti-direction vortexes. These vortexes are developed when they reach the free surface. The results indicate that the flow pattern changes for different values of water height and heater’s power

    Gait recognition using kinect and locally linear embedding

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    This paper presents the use of locally linear embedding (LLE) as feature extraction technique for classifying a person’s identity based on their walking gait patterns. Skeleton data acquired from Microsoft Kinect camera were used as an input for (1). Multilayer Perceptron (MLP) and (2). LLE with MLP. The MLP classification accuracy result was used for comparison between both. Several MLP and LLE properties were tested to find the optimal number of setting that can improve the MLP performance. Based on the two methods used, the neural network implemented with LLE showed the better accuracy compared to the neural network alone.Keywords: locally linear embedding; neural network; multilayer perceptron

    Enhanced Mechanical Properties and Microstructure of Accumulative Roll-Bonded Co/Pb Nanocomposite.

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    Lead composites have been used as anode in electrowinning process to produce metals such as copper and zinc. Manufacturing of stable lead anodes with appropriate mechanical and chemical properties is required to improve the performance of the electrowinning processes. In this study, accumulative roll bonding (ARB) method was used to fabricate Co/Pb nanocomposite. Utilizing ARB method can help us to achieve a uniform structure with enhanced mechanical properties via sever plastic deformation. The results showed that suitable tensile properties were obtained in Pb-%0.5Co-10pass samples. The tensile strength and strain of these samples were 2.51 times higher and 83.7% lower than that of as-cast pure Pb. They also showed creep resistance and hardness up to 1.8 and 2.5 times more than that of as-cast pure Pb. ARB technique uniformly distributed Co par-ticles in the Pb matrix. The enhanced strength of Pb samples was observed in the composite in-cluding grain size less than 50 nm as a result of hindering the recovery phenomenon. The particle size of the Co distributed in the Pb matrix was 353 ± 259 nm. Compared to conventional methods, ARB process improved the mechanical properties of Co/Pb composites and can open a new horizon to fabricate this composite in metal industries
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