Parameter estimation of electric power transformers using Coyote Optimization Algorithm with experimental verification

In this work, the Coyote Optimization Algorithm (COA) is implemented for estimating the parameters of single and three-phase power transformers. The estimation process is employed on the basis of the manufacturer's operation reports. The COA is assessed with the aid of the deviation between the actual and the estimated parameters as the main objective function. Further, the COA is compared with well-known optimization algorithms i.e. particle swarm and Jaya optimization algorithms. Moreover, experimental verifications are carried out on 4 kVA, 380/380 V, three-phase transformer and 1 kVA, 230/230 V, single-phase transformer. The obtained results prove the effectiveness and capability of the proposed COA. According to the obtained results, COA has the ability and stability to identify the accurate optimal parameters in case of both single phase and three phase transformers; thus accurate performance of the transformers is achieved. The estimated parameters using COA lead to the highest closeness to the experimental measured parameters that realizes the best agreements between the estimated parameters and the actual parameters compared with other optimization algorithms

Quantum transport in weakly coupled superlattices at low temperature

We report on the study of the electrical current flowing in weakly coupled superlattice (SL) structures under an applied electric field at very low temperature, i.e. in the tunneling regime. This low temperature transport is characterized by an extremely low tunneling probability between adjacent wells. Experimentally, I(V) curves at low temperature display a striking feature, i.e a plateau or null differential conductance. A theoretical model based on the evaluation of scattering rates is developed in order to understand this behaviour, exploring the different scattering mechanisms in AlGaAs alloys. The dominant interaction in usual experimental conditions such as ours is found to be the electron-ionized donors scattering. The existence of the plateau in the I(V) characteristics is physically explained by a competition between the electric field localization of the Wannier-Stark electron states in the weakly coupled quantum wells and the electric field assisted tunneling between adjacent wells. The influence of the doping concentration and profile as well as the presence of impurities inside the barrier are discussed

Penyelenggaraan fasiliti stadium

Penyelenggaraan adalah kerja yang dilakukan untuk memelihara, menjaga, mengendali, memperbaiki dan mengawalselia struktur bangunan, kemudahan, kelengkapan, perkhidmatan bangunan dan persekitaran bagi memastikan bangunan sentiasa berada pada tahap piawaian yang telah ditetapkan. Selain itu, penyelenggaraan juga dapat mempertahankan utiliti dan nilai fasiliti kemudahan serta berada dalam keadaan selamat digunakan

Urethral advancement procedure in the treatment of primary distal hypospadias: a series of 20 cases

Introduction: Distal hypospadias is the most common genital anomaly, occurring in almost 65% of all hypospadias cases. Although there are several surgical techniques for the treatment of distal hypospadias, it is clear that none can be used to correct all forms of hypospadias. The aim of the study was to evaluate urethral advancement in the repair of primary distal penile hypospadias with regard to feasibility, complication rates and the final cosmetic outcome.Patients and methods: Between October 2014 and June 2015, the urethral mobilization technique was used in 20 patients who presented at the Pediatric Surgery Unit, Tanta University Hospital, with primary distal hypospadias. A submeatal crescent-like incision was performed a few millimeters proximal to the meatus with two vertical incisions from the lateral ends of the submeatal incisions. The urethra within the corpus spongiosum was dissected from the skin of the ventral surface and from the glans and corpora cavernosa for a distance of ~ 4 : 1. The urethra was advanced till the urethral meatus reached its normal position without any tension. Spongioplsty can be performed, and covering Buck’s or Dartos’ layers can be used. The follow-up was conducted on a weekly basis in the outpatient clinic in the first month, and then every month for 6 months.Results: The age of the patient at the time of operation ranged from 6 to 24 months, with a mean age of 10.5 months. The operative time ranged from 60 to 90 min, with a mean time of 73.5 min. Intraoperative urethral injury occurred only in one patient. In all patients, the catheter was removed immediately postoperatively except for one patient who had operative urethral injury. Deep wound infection was noticed in only one patient, followed by partial glanular disruption. Only one patient had urethrocutaneous fistula and two patients had meatal retraction.Conclusion: Urethral advancement can be used safely in the mobilization of the distal urethra with wide glanular dissection and wide lateral mobilization of glanular wings. However, it should be stressed that in the presence of hypoplastic distal urethra and/or persistent ventral curvature, another technique should be adopted. The majority of our patients had very good cosmetic results and minimal complication. However, the technique requires further studies with a larger number of patients and longer follow-up periods to draw more precise and final conclusions.Keywords: distal hypospidaus, primary, urethral advancemen

Virtual integration platform for computational fluid dynamics

Computational Fluid Dynamics (CFD) tools used in shipbuilding industry involve multiple disciplines, such as resistance, manoeuvring, and cavitation. Traditionally, the analysis was performed separately and sequentially in each discipline, which often resulted in conflict and inconsistency of hydrodynamic prediction. In an effort to solve such problems for future CFD computations, a Virtual Integration Platform (VIP) has been developed in the University of Strathclyde within two EU FP6 projects - VIRTUE and SAFEDOR1. The VIP provides a holistic collaborative environment for designers with features such as Project/Process Management, Distributed Tools Integration, Global Optimisation, Version Management, and Knowledge Management. These features enhance collaboration among customers, ship design companies, shipyards, and consultancies not least because they bring together the best expertise and resources around the world. The platform has been tested in seven European ship design companies including consultancies. Its main functionalities along with advances are presented in this paper with two industrial applications

Policy challenges and food security in Alqadarif State, Sudan

Food security is under focused issue in Sudan as a whole and AlQadarif State is not apart from that. According to the integrated food security phases classification (IPC) report April (2015), about 60% of the population suffering from food insecurity in the State. This problem needs to be solved by clear and sound policies and strategies.  The main objective of this study is to investigate and evaluate the Food Security and Nutrition (FSN) policies and strategies in the State. To achieve this objective secondary data such as annual reports, policy documents were collected from all key line institutions and primary data were collected by the mean of a questionnaire the main results of this research are that: there were no clear food security and nutrition policy documents for the key line institutions in the State.  Also, there was a gap between the policymakers at the State level and the locality level. 42% of the policymakers at the locality level did not aware of the existence of the FSN body in the State. About 94% of the policymakers in the localities believed that the Chamber of Zakat plays a very important role in helping at FSN situations. About 92% of policymakers in the state said that finance is not sufficient. The majority of the localities policymakers, 94%, do not have any (FSN) database in their localities. Finally, the main recommendation of this study is to build a food security and nutrition policy/strategy putting the conservation of the natural resources in consideration