A Charge Simulation Based Computer-Aided Design Implementation of High Voltage Systems Modelling

A Charge Simulation based Computer-Aided Design (CAD) Package which facilitates the development of a charge simulation model for high voltage (HV) systems consisting of a number of electrodes and one or two dielectric regions has been developed. The package calculates the potential and electric field distributions for practical systems. It avoids the necessity for creating individual programs for each system studied by allowing the geometry to be specified using a minimum of entered data. The application of the CAD package to several electrode systems which have analytical solutions is presented. Good agreement, generally within 0.5% was found between the fields produced by the Charge Simulation Method (CSM) and the analytical results. A study of the effect of several parameters controlling the charge simulation model is conducted to determine their optimum ranges. Recommendations for these values are made. It is found that for best simulation, discontinuities in alignment of the simulating charges should be avoided. The rod-plane gap configuration and a HV shielding system are modelled and results are compared with existing literature values. Some simulation quality measures which have not previously been published are given. The computation of fields in a sphere/slab arrangement is conducted and results are presented for a wide range of permittivity ratios and gap spacings. It is found that the maximum electric field strength occurs at the triple point for high dielectric constant unrecessed slabs, and away from the axis for low dielectric constant slabs. Two high. voltage systems which have not been analyzed before using the CSM are studied. One is a rotationally symmetrical triggering electrode configuration. The other is a 22 - shed - V - polymer insulator with a grading ring included to reduce the non-linearity of the voltage distribution. In the triggering electrode system it is found that both the main gap distance and the pilot gap distance affect the potential and the field distributions along the axial main gap line. The location of the maximum electric field changes with both gaps and always occurs on the hemispherical part of the triggering electrode, but not necessarily at the tip. Optimum values for the location and size of the grading ring are determined for the polymer insulator. TI1e simulations of additional complicated three-dimensional field problems with and without axial symmetry using the CSM are presented. A tilted rod-electrode versus ground plane and a hemispherical capped rod electrode versus a grounded plane with another offset hemispherically capped electrode embedded are modelled. A detailed examination of the field distribution for a triggering high voltage system without axial symmetry is also presented

Entropy per rapidity in Pb-Pb central collisions using Thermal and Artificial neural network(ANN) models at LHC energies

The entropy per rapidity $d S/d y$ produced in central Pb-Pb ultra-relativistic nuclear collisions at LHC energies is calculated using experimentally observed identified particle spectra and source radii estimated from Hanbury Brown-Twiss (HBT) for particles, $\pi$, $k$, $p$, $\Lambda$, $\Omega$, and $\bar{\Sigma}$, and $\pi$, $k$, $p$, $\Lambda$ and $K_s^0$ at $\sqrt{s}$ $=2.76$ and $5.02$ TeV, respectively. Artificial neural network (ANN) simulation model is used to estimate the entropy per rapidity $d S/d y$ at the considered energies. The simulation results are compared with equivalent experimental data, and good agreement is achieved. A mathematical equation describes experimental data is obtained. Extrapolating the transverse momentum spectra at $p_T$ $=0$ is required to calculate $d S/d y$ thus we use two different fitting functions, Tsallis distribution and the Hadron Resonance Gas (HRG) model. The success of ANN model to describe the experimental measurements will imply further prediction for the entropy per rapidity in the absence of the experiment

The role of 3-methylindole in the aetiology of fog fever in cattle

3-Methylindole (skatole) is a metabolite of L-tryptophan formed in the rumen of cattle. There is considerable evidence that 3-methylindole is the cause of fog fever (acute bovine pulmonary emphysema) in cattle. Experimentally, administration of 3-methyl-indole causes acute pulmonary oedema and emphysema in cattle, goat and sheep. The aim of this study was to investigate the pharmaco-kinetics and mechanism of action of 3-rethylindole with special reference to fog fever, the most important respiratory disease problem of grazing adult cattle in Britain. Samples of ruminal fluid taken from different animals and from the same animal on different days showed considerable variations in their ability to metabolize L-tryptophan to 3-rethylindole, (8-78% conversion of L-tryptophan to 3-methylindole, during 24 hours incubation). These variations provided an explanation for the considerable individual variations in the severity of respiratory distress seen in cattle after oral administration of L-tryptophan and observed after sudden change to better grazing. It was suggested that the increased rate of conversion of L-tryptophan to 3-methylindole, rather than the excessive intake of the amino acid may be responsible for the production of the disease. Certain carbohydrates (fructose, glucose, lactose, galactose, sucrose, mannitol, starch and inulin) substances related to carbohydrates (citrate, lactate, acetate and glycerin) and antibacterial agents (ampicillin, penicillin, streptomycin, tetracycline, chlorar-phenicol, sulfaguanidine and sulfamethoxypyridazine) inhibited, to different degrees, the conversion of L-tryptophan to 3-methylindole. An oral dose of L-tryotophan (0.5 g/kg body weight) did not produce respiratory distress in any of four treated adult cattle. Failure of L-tryptophan to produce the disease was attributed to failure of conversion of the amino acid to 3-rrothylindole which was not detected, in plasma of the treated cattle. The absorption of 3-methylindole, after oral administration in cattle, is rapid. 3-Methyloxindole is a metabolite of 3-methylindole in cattle. Mean plasma half lives of 3-methyloxindole, 3-methylindole and 3-methylindole metabolites were estimated to be 11, 16 and 48 minutes respectively. It was concluded that measurement of the concentration of 3-methyl-indole or 3-methylindole metabolites in single plasma samples would not reflect the magnitude of production of 3-rethylindole in the rumen of cattle. 3-Methylindole (40 mug/ml) and 3-methyloxindole (50 mug/ml) did not cause the release of mediators of anaphylaxis from chopped bovine lung preparations (in vitro). 3-Methylindole and 3-methylindole analogues (3-methyloxindole, 3-phenylindole, 5-methylindole and 7-methylindole) (5-640 mug/ml) did not cause contraction of the isolated pulmonary artery, pulmonary vein, trachea bronchus of calves. It was concluded that the initial step in the pathogenesis of the 3-methylindole-induced pulmonary damage does not involve an action on the pulmonary vein or the release of mediators of anaphylaxis in cattle. Radioactivity from tritiated 3-methylindole became covalently bound to tissues of several organs when tritiated 3-methylindole was administered, intravenously, to calves. Lung tissue showed the highest concentration of covalently bound metabolites. In vitro studies showed that this covalent binding is catalyzed by a microsomal enzyme system with the classical characteristics of a cytochrome P-450 dependent mixed function oxidase. This enzyme system activates 3-methylindole to a chemically reactive highly electrophilic metabolite which becomes covalently bound to nucleophilic sites on cellular macromolecules. The 3-methylindole-reactive metabolite can be detoxified by spontaneous and glutathione-S-transferase-catalyzed conjugation with glutathione. Pretreatment of sheep with diethylmaleate (depletes glutathione) and L-cysteine (increases glutathione) was shown to increase and decrease, respectively, the severity of pneumotoxic effect of 3-methylindole. 3-Methyloxindole did not become covalently bound to microsomal proteins, in vitro, and did not cause acute pulmonary toxic effects similar to those produced by 3-methylindole, in vivo, suggesting that the 3-methylindole-reactive metabolite is intermediate between 3-methylindole and 3-methyloxindole. The liver possess an enzyme system capable of catalyzing the covalent binding of 3-methylindole metabolites to microsomal proteins, in vitro. This enzyme system was qualitatively identical to that of the lung. The Michaelis constants of the lung and liver systems were 0.37 and 0.44 mnol 3-methylindole and maximal velocities of microsomal alkylation were 100 and 556 pmol covalently bound 3-methylindole/mg microsomal protein/minute, respectively. These findings suggest that the specificity of 3-methylindole towards the lung is not due to higher rate of reactive metabolite formation in the lung, but is probably due to deficiency of the lung in defence mechanisms against this reactive metabolite

Obstacles of Achieving Total Quality in the Faculty of Education in Alexandria University from Staff’s Perspective

هدفت الدراسة لتحديد معوقات تحقيق الجودة الشاملة في كلية التربية جامعة الإسكندرية كما يراها أعضاء هيئة التدريس، وسبل علاجها ووضع خطط للتغلب عليها، وقياس أثر متغيرات (الجنس – الدرجة العلمية – التخصص) على آراء أعضاء هيئة التدريس حول معوقات تطبيق الجودة الشاملة في مجالات (التدريس والتعليم، البحث العلمي، خدمة المجتمع، الإدارة الجامعية، والجوانب الشخصية لأعضاء هيئة التدريس). واعتمدت الدراسة على استخدام المنهج الوصفي، واستخدمت استبانة حول معوقات تحقيق الجودة الشاملة بكلية التربية جامعة الإسكندرية، وطبقت على عينة مكونة من (100) عضو من أعضاء هيئة التدريس بالكلية, وأوضحت النتائج أن المعوقات تمثلت في: معوقات الإدارة الجامعية والتي حصلت على أعلى متوسط حسابي (4.5) بدرجة موافقة كبيرة جدًا، ثم معوقات التدريس والتعليم بمتوسط حسابي (4.2) بدرجة موافقة كبيرة، ثم معوقات البحث العلمي بمتوسط حسابي (3.9) بدرجة موافقة كبيرة، ثم معوقات خدمة المجتمع بمتوسط حسابي (3.5) بدرجة موافقة كبيرة، ثم المعوقات المرتبطة بالجانب الشخصي لعضو هيئة التدريس على متوسط حسابي (3.4) بدرجة موافقة كبيرة. وأوضحت النتائج عدم وجود فروق ذات دلالة إحصائية في وجهات نظر أعضاء هيئة التدريس في عينة الدراسة تجاه معوقات تطبيق الجودة في كلية التربية بجامعة الإسكندرية تعزى لمتغيرات (الجنس، أو الدرجة العلمية، أو التخصص). الكلمات المفتاحية: الجودة الشاملة، معوقات، أعضاء هيئة التدريس، كلية التربية.  This study investigated obstacles that prevent achieving total quality in the faculty of Education in Alexandria University from the point of view of the faculty members in order to provide methods for overcoming such obstacles. The study also aimed to measure the impact of the variables (gender – academic rank – the major) on the staff's views in the fields of (teaching, learning – scientific research – community service – university administration – staff's personal aspects). The study was based on the descriptive method and used a questionnaire to a sample of (100) teaching staff members who were randomly selected. The results revealed that the obstacles were as follows: i) obstacles of university administration with a mean of (4.5) indicating a very high agreement score, ii) obstacles of teaching and learning process with a mean of (4.2) indicating a high agreement score, iii) obstacles of the scientific research with a mean of (3.9) indicating a high agreement score, iv) obstacles of the community service with a mean of (3.5) indicating a high agreement score and v) obstacles related to the staff members’ personal aspects with a mean of (3.4) indicating an average agreement score. The results showed no statistically significant differences between the staff's views regarding about obstacles of applying total quality in the Faculty of Education, Alexandria University attributed to gender, academic rank or major. Keywords: Quality, Faculty of education, Staff members, TQM obstacles

Energy Harvesting Communication Networks: Online Policies, Temperature Considerations, and Age of Information

This dissertation focuses on characterizing energy management policies for energy harvesting communication networks in the presence of stochastic energy arrivals and temperature constraints. When the energy arrivals are stochastic and are known only causally at the transmitter, we study two performance metrics: throughput and age of information (AoI). When the energy harvesting system performance is affected by the change of the temperature, we consider the throughput metric. When the energy arrivals are stochastic, we study the throughput maximization problem for several network settings. We first consider an energy harvesting broadcast channel where a transmitter serves data to two receivers on the downlink. The battery at the transmitter in which the harvested energy is stored is of finite size. We focus on online transmission schemes where the transmitter knows the energy arrivals only causally as they happen. We consider the case of general independent and identically distributed (i.i.d.) energy arrivals, and propose a near-optimal strategy coined fractional power constant cut-off (FPCC) policy. We show that the FPCC policy is near-optimal in that it yields rates that are within a constant gap from the optimal rate region, for all system parameters. Next, we study online transmission policies for a two-user multiple access channel where both users harvest energy from nature. The energy harvests are i.i.d. over time, but can be arbitrarily correlated between the two users. The transmitters are equipped with arbitrary but finite-sized batteries. We propose a distributed fractional power (DFP) policy, which users implement distributedly with no knowledge of the other user's energy arrival or battery state. We show that the proposed DFP is near-optimal as in the broadcast channel case. Then, we consider online power scheduling for energy harvesting channels in which the users incur processing cost per unit time that they are on. The presence of processing costs forces the users to operate in a bursty mode. We consider the single-user and two-way channels. For the single-user case, we consider the case of the general i.i.d.~energy arrivals. We propose a near-optimal online policy for this case. We then extend our analysis to the case of two-way energy harvesting channels with processing costs; in this case, the users incur processing costs for being on for transmitting or receiving data. Our proposed policy is distributed, which users can apply independently with no need for cooperation or coordination between them. Next, we consider a single-user channel in which the transmitter is equipped with finite-sized data and energy buffers. The transmitter receives energy and data packets randomly and intermittently over time and stores them in the finite-sized buffers. The arrival amounts are known only causally as they happen. We focus on the special case when the energy and data arrivals are fully-correlated. We propose a structured policy and bound its performance by a multiplicative gap from the optimal. We then show that this policy \emph{is optimal} when the energy arrivals dominate the data arrivals, and is \emph{near-optimal} when the data arrivals dominate the energy arrivals. Then, we consider another performance metric which captures the freshness of data, i.e., AoI. For this metric, we first consider an energy harvesting transmitter sending status updates to a receiver over an erasure channel. The energy arrivals and the channel erasures are i.i.d. and Bernoulli distributed in each slot. In order to combat the effects of the erasures in the channel and the uncertainty in the energy arrivals, we use channel coding to encode the status update symbols. We consider two types of channel coding: maximum distance separable (MDS) codes and rateless erasure codes. For each of these models, we study two achievable schemes: best-effort and save-and-transmit. We analyze the average AoI under each of these policies. We show that rateless coding with save-and-transmit outperforms all other schemes. Next, we consider a scenario where the transmitter harvests i.i.d. Bernoulli energy arrivals and status updates carry information about an independent message. The transmitter encodes this message into the timings of the status updates. The receiver needs to extract this encoded information, as well as update the status of the observed phenomenon. The timings of the status updates, therefore, determine both the AoI and the message rate (rate). We study the trade-off between the achievable message rate and the achievable average AoI. We propose several achievable schemes and compare their rate-AoI performances. Then, with the motivation to understand the effects of temperature sensitivity on wireless data transmission performance for energy harvesting communication networks, we study several temperature models. We assume non-causal knowledge of the energy arrivals. First, we consider throughput maximization in a single-user energy harvesting communication system under continuous time energy and temperature constraints. We model three main temperature related physical defects in wireless sensors mathematically, and investigate their impact on throughput maximization. Specifically, we consider temperature dependent energy leakage, effects of processing circuit power on temperature, and temperature increases due to the energy harvesting process itself. In each case, we determine the optimum power schedule. Next, different from the previous work, we consider a discrete time system where transmission power is kept constant in each slot. We consider two models that capture different effects of temperature. In the first model, the temperature is constrained to be below a critical temperature at all time instants; we coin this model as explicit temperature constrained model. We investigate throughput optimal power allocation for multiple energy arrivals under general, as well as temperature and energy limited regimes. In the second model, we consider the effect of the temperature on the channel quality via its influence on additive noise power; we coin this model as implicit temperature constrained model. In this model, the change in the variance of the additive noise due to previous transmissions is non-negligible. In particular, transmitted signals contribute as interference for all subsequent slots and thus affect the signal to interference plus noise ratio (SINR). In this case, we investigate throughput optimal power allocation under general, as well as low and high SINR regimes. Finally, we consider the case in which implicit and explicit temperature constraints are simultaneously active. Finally, we extend the discrete time explicit temperature constraint model to a multi-user setting. We consider a two-user energy harvesting multiple access channel where the temperatures of the nodes are affected by the electromagnetic waves due to data transmission. We study the optimal power allocations when the temperatures of the nodes are subject to peak temperature constraints, where each node has a different peak temperature requirement and the nodes have different temperature parameters. We study the optimal power allocation in this case and derive sufficient conditions under which the rate region collapses to a single pentagon

Synchronous reluctance motor iron losses: considering machine non-linearity at MTPA, FW, and MTPV operating conditions

Synchronous reluctance machine has high flux density fluctuations in the iron due to the high harmonics results from the rotor anisotropy. Thus, an accurate computation of the iron losses is of paramount importance, especially during the design stage. In this paper, a non-linear analytical model considering the magnetic iron saturation and the slotting effect is proposed. The model estimates accurately the iron losses at a wide range of operating speed. In addition, the accuracy of the non-linear model when the machine is highly saturated, i.e. when it works along the MTPA trajectory, is presented and verified. The model presented is general and can be applied to other configurations. A 36-slot four-pole machine, with three flux-barriers per pole is considered as a case study. Finite element analysis is used to validate the results achieved by means of the non-linear analytical model. Furthermore, an experimental setup is built to validate the simulation results

Particle production and chemical freezeout from the hybrid UrQMD approach at NICA energies

The energy dependence of various particle ratios is calculated within the Ultra-Relativistic Quantum Molecular Dynamics approach and compared with the hadron resonance gas (HRG) model and measurements from various experiments, including RHIC-BES, SPS and AGS. It is found that the UrQMD particle ratios agree well with the experimental results at the RHIC-BES energies. Thus, we have utilized UrQMD in simulating particle ratios at other beam energies down to 3 GeV, which will be accessed at NICA and FAIR future facilities. We observe that the particle ratios for crossover and first-order phase transition, implemented in the hybrid UrQMD v3.4, are nearly indistinguishable, especially at low energies (at large baryon chemical potentials or high density).Comment: 13 pages, 5 figures, 2 tables, one reference is added and one paragraph is rephrased. To appear in EPJ