Transient behaviour of a group of induction motors

The non-linear differential equations describing the transient behaviour of a group of induction motors are developed from the equations for a single machine. These equations enable the behaviour of each machine in the group to be investigated, either when the complete group is connected to a stiff supply or when the supply is weak and the machine behaviour is interactive. A numerical solution of the equations using a digital computer is used to predict the transient currents and torques of a 0.75 kW/1.5 kW motor group and of a 0.75 kW/1.5 kW/2.25 kW motor group, and the results obtained are compared with experimentally obtained results. [Continues.

A new Solar Desalination System Design and Heat Recovery

The work evaluates experimentally technique toimprove fresh water production by careful energy recovery inthe vapour condensation processes; the recovered heat in turnon drives additional evaporation and preheats the feedwater. Apilot plant is designed and constructed in an arid area with 2 m2solar evaporation collector area to evaluate the process. Thisunit is tested on cold and hot days. The effect of mainparameters on fresh water production of the unit is studied. Theexperimental results show that, the production rate andefficiency of the system are strongly affected by solar radiationand level water in solar evaporation collector. Within the studiedranges, the maximum productivity reached to 16.1 kg/ m2day atTvap,av = 87.6 oC , solar radiation 842 W/m2 and level water 1.912kg. According to these results, fresher water production of thepresent system is higher than that solar still desalination systemin the previous studies

Synthesis and characterization of metallic materials for membrane technology

AbstractPowder of metallic materials composed of Fe, Ni was proposed for membrane applications such as microfiltration devices. The powder was synthesized using thermal route of simultaneously sintering–reduction techniques. The resulting powder has specific porous structure and can be deposited on steel substrate. The formed phases were identified by X-ray phase analysis. The produced powder was characterized by reflected light microscope and scanning electron microscope along with energy-dispersive X-ray spectroscopy (EDX). The reduction behavior of metal oxides was followed up by thermogravimetric techniques. The kinetics data obtained from reduction process were used to elucidate the reduction mechanism under isothermal condition. The microstructure changes accompanying sintering–reduction processes were investigated under different experimental parameters such as temperature, holding time and gas composition. The results show that pure Fe0.64Ni0.36 with relatively high porosity can be fabricated via reduction route. The presence of NiO plays a significant role in the reduction of iron oxide as well as in the structural changes accompanying the reduction processes. The particle size distribution of the produced metallic materials is being controlled under the different operation conditions to get a homogenous porous metallic structure with well defined porosity. The main advantage of using porous ferroalloy materials is their narrow size distribution leading to a well defined pore size distribution after sintering and reduction

Dysphagia related quality of life and its association with cognitive function and sociodemographic factors among older stroke patients in Amman, Jordan

Dysphagia is a disorder that compromises the movement of food and liquids from the mouth to the stomach. It is a frequent disorder in stroke patients, affecting 50% to 80% of them. Dysphagia and its complications negatively impact the emotional, functional, and physical aspects of stroke patients. Moreover, cognitive impairment is one of the most common disabilities after a stroke, affecting 20% to 80% of stroke survivors. Previous studies have shown that the severity of dysphagia increases with the severity of cognitive dysfunction. However, the correlation between cognitive function and the handicapping effect of dysphagia on emotional, functional, and physical aspects of quality of life (QOL) in stroke patients is still unknown. Thus, this study aimed to investigate the correlation between cognitive function and the handicapping effect of dysphagia on emotional, functional, and physical aspects of QOL in stroke patients. A total of 31 stroke patients with dysphagia participated in this cross-sectional study. The Arabic version of the Montreal Cognitive Assessment (MoCA) was used to assess patients' cognitive function. Furthermore, the Arabic version of the Dysphagia Handicap Index (DHI) was used to assess the emotional, functional, and physical effects of dysphagia in stroke patients. Most of the patients (61.3%) were male, and the majority (67.7%) were between 60-70 years old. The findings showed that 35.5% of the patients had impaired cognitive function, and the mean ± SD of the DHI total score was 53.5 ± 9.6. Moreover, the results indicated that there was a statistically significant difference in the means of the physical subscale (p=0.003), emotional subscale (p=0.020), and the DHI total score (p=0.005) between groups with different onsets of dysphagia, indicating that the handicapping effect of dysphagia on the physical and emotional aspects, and overall QOL decreases with time following a stroke. Additionally, the findings showed a weak negative correlation between cognitive function (MoCA total score) and the handicapping effect of dysphagia on the physical subscale (r = -0.418, p = 0.019) and the DHI total score (r = -0.368, p = 0.042). Our findings suggest that dysphagia negatively affects QOL aspects, and cognitive function may have a role in the severity of the handicapping effect of dysphagia on the QOL aspects. Thus, looking into the affected QOL aspects secondary to the debilitating dysphagia and the associated cognitive function will be very helpful for dysphagia management and rehabilitation

Association of high sensitive C reactive protein and dialysis adequacy with uremic pruritus in hemodialysis patients

Introduction: Uremic pruritus is one of the most common and complicated symptom affecting hemodialysis patients, it can be persistent, distressing and having a significant impact on the quality of life. We aimed to study the relationship between high sensitive C reactive protein and adequacy of dialysis with uremic pruritus in hemodialysis patients. Patients and Methods: In this Case control study one hundred prevalent hemodialysis patients were enrolled from hemodialysis units in Ain Shams University hospitals, fifty of them had pruritus and the other fifty patients had no pruritis, all of them underwent urea reduction ratio for dialysis adequacy assessment, pruritus assessment by using visual analog scale and high sensitive C reactive protein serum level. Results: Uremic pruritus has statistically significant negative correlation with urea reduction ratio and consequently with dialysis adequacy. However, uremic pruritus has statistically significant positive correlation with highly sensitive C reactive protein serum levels in hemodialysis patients. Conclusion: Inadequate hemodialysis and increased hsCRP serum level play an important role in aggravating intensity and severity of uremic pruritus

Reusing three-phase power-flow object components for unbalanced harmonic analysis

In this paper, the harmonic penetration method is developed as a component-based application. The direct nodal voltage harmonic solution is developed as an independent software component and then integrated with existing three-phase power-flow software components. The harmonic solution reuses many facilities available in the fundamental frequency power-flow object components. The nonlinear devices such as six pulse converters are modeled as entity objects and inherited from the basic object-oriented power-system device model at fundamental frequency. Also, the linear solver also is reused form the power-flow component library. The application of object components shows that the development of complicated algorithms becomes easy due to the high code reusability

The wave equation approach to an inverse eigenvalue problem for an arbitrary multiply connected drum in ℝ

The spectral function μˆ(t)=∑j=1∞exp(−itμj1/2), where {μj}j=1∞ are the eigenvalues of the two-dimensional negative Laplacian, is studied for small |t| for a variety of domains, where −∞<t<∞ and i=−1. The dependencies of μˆ(t) on the connectivity of a domain and the Robin boundary conditions are analyzed. Particular attention is given to an arbitrary multiply-connected drum in ℝ2 together with Robin boundary conditions on its boundaries

Crude Coal Tar and Ultraviolet (UV) A radiation (Modified Goeckerman Technique) in Treatment of Psoriasis

Background: Psoriasis is a chronic inflammatory dermatosis that has a substantial impact on the quality of life. Goeckerman\u27s technique (GT) has been recruited for the treatment of psoriasis with high clearance rates and long periods of remission.Psoriasis is a chronic inflammatory dermatosis that has a substantial impact on the quality of life. Goeckerman’s technique (GT) has been implemented for the treatment of psoriasis with high clearance rates and long periods of remission. The objective of this article was to evaluate the efficacy and safety of modified GT (crude coal tar 2.5% plus UVA) as an alternative therapeutic modality for psoriatic patients with skin types III-V. Twenty two patients with moderate, severe, and erythrodermic psoriasis were included in this study. All patients received modified GT (crude coal tar 2.5% plus UVA) six days per week for a period of 3 months. Assessment of the rate of reduction of psoriasis area severity index (PASI) was performed, as well as photographic documentation of each patient at baseline and after completion of therapy. There was a significant reduction in PASI scores after therapy in all patients (P=0.001). The rate of PASI reduction after therapy was &gt;50% in 63.6% of patients; 27.3% of patients achieved &gt;75% reduction and 9.1% of patients achieved 26-50% reduction. No serious side effects were reported in any of the patients. Modified GT is a safe and effective therapeutic option for patients with moderate and severe psoriasis.</p

Synthesis and biological activities of some new fully fused quinazoline derivatives

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