804 research outputs found

    The performance of pulsed-pressure wetted-wall distillation columns

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    The main purpose of this work was to investigate the characteristics and operational performance of pulsed wetted-wall distillation columns at total reflux and using the binary system methylcyclohexane/toluene. The results of a detailed study on three concentric-tube, wetted-wall columns are given both with the application of pulsations on the vapour phase and without. Marked improvement in the performance of the columns expressed as number of transfer units (N.T.U.) was obtained by using pulsations in the range of 0–21 cycles/sec, even to the extent of quadrupling the efficiency. It was found that an increase in efficiency was obtained for both increase in amplitude and frequency and that there exists a maximum efficiency at an approximate frequency of 17 cycles per second. [Continues.

    Motor Capabilities of Lower Limb Amputated Patients and Its Relation to Body Image and Depression

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    Background: Lower limb amputation is a great event in the life of individual’s which having an counteractive effect on overall physical, psychological and social functioning of an individual so the study aim is to measure relation of motor capabilities of lower limb amputated patients on body image and depression level. Methods: Design: The descriptive correctional research design was utilized to achieve the aim of the study. Sample: A convenient sample of sixty four participant consisted of male and female adult amputee patients. Setting: This study was conducted in Rheumatology and Rehabilitation Department at Minia University Hospital. Tools of data collection: Three scales and one tool were utilized; Bio socio-demographic characteristic and structured interview, Locomotor Capabilities Index, Amputee Body Image Scale and Beck Depression Inventory (BDI) scale. Results: 73.5% of the amputated patients have low locomotor capabilities while 93.7% of the study sample has a low body image and 31.2% of the study sample suffers from moderate depression after 6 month from amputation and high positive significant correlation between locomotor capabilities and body image, while that there was a high negative significant correlation between locomotor capabilities and depression level among the imputed patients. Conclusions: The recent amputee patients that are have lower limb prosthesis suffer from low locomotor capabilities and theses have negative impact on their body image and depression level. Recommendation: A well planned structured rehabilitation program should be done to the specific needs of people with limb amputation in order to be able to find out its impact on their functional abilities, body image and depression level. Keywords: Amputation,  locomotors capabilities, Body image, Depression. DOI: 10.7176/JHMN/64-03 Publication date:July 31st 201

    Pitman estimator for the parameter and reliability function of the exponential distribution

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    The easiest and most essential distribution in reliability studies is the exponential distribution. An important issue in this area is to seek for a good estimator to estimate the parameter and reliability function of this distribution. So in this article, The Pitman method is used to derive an estimator for the parameter and reliability function of the exponential distribution, then a comparison was made with the usual methods such as maximum likelihood estimator and Bayes estimator through simulation studies with different sizes of samples. The results showed that the Pitman estimator has a good performance for the parameter of exponential distribution compared with other methods by relying on the statistical measure Mean square error. Also it showed that the Bayes estimator has a good performance compared with the other methods in estimating the reliability function by relying on the statistical measure integral mean square error

    Price Clustering After the Introduction of Bitcoin Futures

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    Economic theory suggests that introduction of derivative contracts can improve the informational efficiency of the underlying asset prices (Danthine, 1978). In this study, we examine the impact of the introduction of Bitcoin futures on price clustering in Bitcoin. Our findings suggest that price clustering in Bitcoin meaningfully decreases post the introduction of its futures contracts

    OPTIMAL SLIDING MODE CONTROLLER DESIGN BASED ON WHALE OPTIMIZATION ALGORITHM FOR LOWER LIMB REHABILITATION ROBOT

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    The Sliding Mode Controllers (SMCs) are considered among the most common stabilizer and controllers used with robotic systems due to their robust nonlinear scheme designed to control nonlinear systems. SMCs are insensitive to external disturbance and system parameters variations. Although the SMC is an adaptive and model-based controller, some of its values need to be determined precisely. In this paper, an Optimal Sliding Mode Controller (OSMC) is suggested based on Whale Optimization Algorithm (WOA) to control a two-link lower limb rehabilitation robot. This controller has two parts, the equivalent part, and the supervisory controller part. The stability assurance of the controlled rehabilitation robot is analyzed based on Lyapunov stability. The WO algorithm is used to determine optimal parameters for the suggested SMC. Simulation results of two tested trajectories (linear step signal and nonlinear sine signal) demonstrate the effectiveness of the suggested OSMC with fast response, very small overshoot, and minimum steady-state error
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