181 research outputs found

    Eighth Amendment Meanings from the ABA’s Moratorium Resolution

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    Bilionis argues that the American Bar Association\u27s moratorium resolution on capital punishment doesn\u27t challenge the capacity of the Eighth Amendment

    Information systems application on reinforced concrete beams subjected to shear and torsion

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    Information Systems Application on Reinforced Concrete Beams Subjected to Shear and TorsionA. M. El-Nady R. Morsy AbstractInformation technology plays a key role in every aspect of structural engineering field. It has been implemented for a long time in all design and construction stages. One of the main objectives of using information technology is saving time and cost. Most of its application was focused on analysis, design, drawings and visual presentations. However, very little research was focused on managing the huge amount of related available information.In this study, a platform for combining both analytical calculations and knowledge management for the design of reinforced concrete elements is investigated. Considering that reinforced concrete design is governed by a widely available specifications, limitations and related information, the recent developments in information technology should be utilized to facilitate an easier and more reliable design techniques. This study investigates the possibility of building a structured database for design limitations, specifications and related information to support designers. An application of the suggested system is introduced for the design of reinforced concrete beams subjected to shear and torsion. In addition, information technology with graphical interface is combined with the aforementioned technique to present a hybrid platform

    Perceptions of Existing Wearable Robotic Devices for Upper Extremity and Suggestions for Their Development: Findings From Therapists and People With Stroke

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    Background: Advances in wearable robotic technologies have increased the potential of these devices for rehabilitation and as assistive devices. However, the utilization of these devices is still limited and there are questions regarding how well these devices address users’ (therapists and patients) needs. Objective: The aims of this study were to (1) describe users’ perceptions about existing wearable robotic devices for the upper extremity; (2) identify if there is a need to develop new devices for the upper extremity and the desired features; and (3) explore obstacles that would influence the utilization of these new devices. Methods: Focus groups were held to collect data. Data were analyzed thematically. Results: A total of 16 participants took part in the focus group discussions. Our analysis identified three main themes: (1) “They exist, but...” described participants’ perceptions about existing devices for upper extremity; (2) “Indeed, we need more, can we have it all?” reflected participants’ desire to have new devices for the upper extremity and revealed heterogeneity among different participants; and (3) “Bumps on the road” identified challenges that the participants felt needed to be taken into consideration during the development of these devices. Conclusions: This study resonates with previous research that has highlighted the importance of involving end users in the design process. The study suggests that having a single solution for stroke rehabilitation or assistance could be challenging or even impossible, and thus, engineers should clearly identify the targeted stroke population needs before the design of any device for the upper extremity

    Experimental study of film cooling and heat transfer on a gas turbine vane with shaped holes

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    Improving the film cooling technique provides more cooling capacity to withstand the harsh thermal environment in the next generation of gas turbines. A two-dimensional cascade has been designed and constructed in a subsonic wind tunnel in order to investigate the heat transfer of shaped holes over a gas turbine stator. An in-situ calibration technique has been developed to obtain the film cooling performance without disturbing the aerodynamic flow around the vane surface. Subsequently, the cooling performance of two types of shaped holes is measured at different positions over the entire surface. Firstly, a louver scheme was investigated on the convex surface of the suction side and on the concave surface of the pressure side. In addition, a proposed smooth expansion was investigated over the highly curved surface of the leading edge. The location of the hole has a high impact on the cooling performance due to the difference in curvature. The investigated blowing ratios slightly affect the cooling performance of the presented schemes due to the considerable reduction in the jet momentum that impedes the jet lift-off at exit. The shaped holes provide a higher net heat flux reduction compared with the similar cylindrical holes and other shaped holes in the literature. The contribution of this study will help to enhance the cooling performance in the next generation of gas turbines

    First Order Integral Sliding Mode Control for Active and Reactive Current of A Multilevel Inverter Based Distributed Generation Unit

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    Abstract. This paper presents an innovative control scheme for Distributed Generation Systems, DGS, using an efficient version of the first order Sliding Mode Control, SMC. The control law of the SMC is modified in order to improve the tracking and reduce the chattering over the conventional SMC. The modification is focused on the definition of the sliding manifold, sliding surface, which contains an integral term of the error not a differential term like the conventional SMC. The proposed control scheme is applied to a multilevel diode clamped inverter based Distributed Generation Unit, DGU. The proposed control scheme is developed to control the active and reactive currents injected or absorbed by the power grid. Simulation results are provided to prove the viability of the proposed formulation and practicality of the presented sliding mode controller for the distributed generation system

    Journal Staff

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    This paper discusses the effect of high level multi-tone acoustic excitation on the acoustic properties of perforates. It is based on a large experimental study of the nonlinear properties of these types of samples without mean grazing or bias flow. Compared to previously published results the present investigation concentrates on the effect of multiple harmonics. It is known from previous studies that high level acoustic excitation at one frequency will change the acoustic impedance of perforates at other frequencies, thereby changing the boundary condition seen by the acoustic waves. This effect could be used to change the impedance boundary conditions and for instance increase the absorption. It could obviously also pose a problem for the correct modelling of sound transmission through ducts lined with such impedance surfaces. Experimental results are compared to a quasi-stationary model. The effect of the combination of frequency components and phase in the excitation signal is studied.QC 20131030</p

    Measuring Egyptian Farmers’ Attitude Towards Staying Organic

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    Organic agriculture (OA) in Egypt is well-developed and still fast growing. Improving the relation between organic farmers and the other agents in the chain can provide a positive contribution to the whole organic chain competitiveness. One possible approach to investigate the farmers’ perceived role and satisfaction within the organic system is to explore the factors influencing their decision to stay organic. In particular, the aim of the present study was to measure the farmers’ attitude towards staying organic. Organic agricultural experts and institutional stakeholders were interviewed to complete a literature review and to obtain information about the Egyptian context. The survey questionnaire was pre-tested (n = 13) and then administered to a different sample (n = 232). A split-half validation procedure was used to evaluate and then confirm the factor structure. Explorative and confirmatory factor analysis yielded a final 29-item measure consisting of 8 distinct factors showing how organic agriculture influences a broad range of farmers’ life dimensions (environmental, economic, social, psychological). The significant role played by psychological and social factors in defining the farmers’ decision to stay organic emerged as a relatively unexpected outcome. The study supports the sustainable development of small family farmers, providing a useful tool to support the growth of organic production and consumption, mostly in developing countries. By monitoring farmers’ attitudes and perception towards OA, the instrument proposed in the present study can support policy makers, farmers’ organizations, civil society organizations (NGOs) and organic chains focal companies when defining policies, advocating campaigns, and chain coordination strategies for farmers involved in the organic food system development

    Optimum PID Controller with Fuzzy Self-Tuning for DC Servo Motor

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    DC motors are simple and controllable, making them a popular choice for various applications. However, the speed and load characteristics of DC motors can change, making it difficult to control them effectively. This paper proposes an optimum PID controller with fuzzy self-tuning for DC servo motors. The controller uses two steps to adjust the PID gains: The ACS algorithm is employed to identify the optimal PID gains in the first step. A fuzzy logic (FLC) controller is employed in the second stage to further fine-tune the gains. The FLC considers two cost functions: the first function is the sum of the squares of the error between the controlled output and reference input. The second function is a mathematical expression that specifies the required characteristics of the system response. The fuzzy self-tune then uses a set of rules to adjust the PID gains in response to changes in the system. The rules are based on the two cost functions designed to maintain the optimum PID gains for various operating settings. The outcomes of the two functions are: Kp = 5.2381, Ki = 7.0427, and Kd = 0.49468, with rising time = 0.2503, overshoot = 2.5079, and settling time = 10.4824 in the first cost function. The second cost function outcomes are Kp = 8.1381; Ki = 8.6427; and Kd = 0.49468. The FST-PID controller's performance is evaluated using Matlab-Simulink. The proposed controller was tested on a DC servo motor, and the results showed good performance in both steady-state and transient responses. The controller also maintained the optimum PID gains in the event of changes or disturbances. So, the motor's speed can effectively control under a variety of conditions

    MicroRNAs as Potential Biomarkers for Childhood Epilepsy

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    BACKGROUND: Epilepsy is the most frequent chronic neurologic condition in childhood. Its clinical diagnosis is based on electroencephalograms (EEG) and neuroimaging techniques. MicroRNAs (miRNAs) modulate gene expression of several genes and are aberrantly expressed in several diseases. AIM: Evaluation of using circulating miR-106b and miR-146a as diagnostic and prognostic biomarkers in children patients with epilepsy. METHODS: Thirty epileptic children and twenty controls were enrolled in our study. They were assessed for the expression pattern of miR-106b and miR-146a in plasma using quantitative real-time PCR and determination of plasma Immunoglobulin levels. RESULTS: MiR-146a and miR-106b expression patterns were significantly up-regulated in children patients than that in normal controls. Plasma Immunoglobulins were differentially expressed in epileptic patients in comparison with healthy controls. No correlations were found between expression levels of miRNAs (miR-146a and miR-106b) and clinical data or immunoglobulin levels in children patients with epilepsy. CONCLUSION: Our findings suggest that up-regulated plasma miR-106b and miR-146a could be used as biomarkers for epilepsy evaluation

    Analysis of acoustic networks including cavities by means of a linear finite volume method

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    [EN] A procedure allowing for the analysis of complex acoustic networks, including three-dimensional cavities described in terms of zero-dimensional equivalent elements, is presented and validated. The procedure is based on the linearization of the finite volume method often used in gas-dynamics, which is translated into an acoustic network comprising multi-ports accounting for mass exchanges between the finite volumes, and equivalent 2-ports describing momentum exchange across the volume surfaces. The application of the concept to a one-dimensional case shows that it actually converges to the exact analytical solution when a sufficiently large number of volumes are considered. This has allowed the formulation of an objective criterion for the choice of a mesh providing results with a prefixed error up to a certain Helmholtz number, which has been generalized to three-dimensional cases. The procedure is then applied to simple but relevant three-dimensional geometries in the absence of a mean flow, showing good agreement with experimental and other computational results.This work has been partially supported by Ricardo Software, and by Ministerio de Ciencia e Innovacion through Grant DPI2009-14290. The authors thank Dr. F.D. Denia for his kind computational assistance.Torregrosa, AJ.; Broatch, A.; Gil, A.; Moreno MartĂ­nez, D. (2012). Analysis of acoustic networks including cavities by means of a linear finite volume method. Journal of Sound and Vibration. 331(20):4575-4586. https://doi.org/10.1016/j.jsv.2012.05.023S457545863312
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