Efficient method for transformer models implementation in distribution load flow matrix

Introduction. Most distribution networks are unbalanced and therefore require a specific solution for load flow. There are many works on the subject in the literature, but they mainly focus on simple network configurations. Among the methods dedicated to this problem, one can refer to the load flow method based on the bus injection to branch current and branch current to bus voltage matrices. Problem. Although this method is regarded as simple and complete, its drawback is the difficulty in supporting the transformer model as well as its winding connection types. Nevertheless, the method requires the system per unit to derive the load flow solution. Goal. In the present paper, our concern is the implementation of distribution transformers in the modeling and calculation of load flow in unbalanced networks. Methodology. Unlike previous method, distribution transformer model is introduced in the topology matrices without simplifying assumptions. Particularly, topology matrices were modified to take into account all winding types of both primary and secondary sides of transformer that conserve the equivalent scheme of an ideal transformer in series with an impedance. In addition, the adopted transformer models overcome the singularity problem that can be encountered when switching from the primary to the secondary side of transformer and inversely. Practical value. The proposed approach was applied to various distribution networks such as IEEE 4-nodes, IEEE 13-nodes and IEEE 37-nodes. The obtained results validate the method and show its effectiveness.Вступ. Більшість розподільчих мереж незбалансовані і тому потребують спеціального рішення для потоку навантаження. У літературі є багато робіт на цю тему, але переважно вони присвячені простим мережевим конфігураціям. Серед методів, присвячених цій проблемі, можна назвати метод потоку навантаження, заснований на введенні шини в матрицю струму відгалуження і відгалуження струму в матрицю напруги шини. Проблема. Хоча цей метод вважається простим та повним, його недоліком є складність підтримки моделі трансформатора, а також типів з’єднання його обмоток. Проте метод вимагає системи на одиницю для отримання рішення про потік навантаження. Мета. У цій статті нас цікавить застосування розподільних трансформаторів для моделювання та розрахунку потоку навантаження у незбалансованих мережах. Методологія. На відміну від попереднього методу, модель розподільного трансформатора вводиться в матриці топології без спрощення припущень. Зокрема, матриці топології були змінені, щоб врахувати всі типи обмоток як первинної, так і вторинної сторін трансформатора, які зберігають еквівалентну схему послідовно ідеально включеного трансформатора з імпедансом. Крім того, прийняті моделі трансформаторів долають проблему сингулярності, з якою можна зіткнутися при перемиканні з первинної на вторинну обмотку трансформатора і навпаки. Практична цінність. Пропонований підхід був застосований до різних розподільних мереж, таких як IEEE з 4 вузлами, IEEE з 13 вузлами та IEEE з 37 вузлами. Отримані результати підтверджують метод та показують його ефективність

Fistule carotido-caverneuse post-traumatique

Introduction : La fistule carotido-caverneuse (FCC) est une complication rare, mais grave des traumatismes craniofaciaux pouvant engager le pronostic fonctionnel oculaire et le pronostic vital. elle réalise une communication anormale entre le système artériel carotidien et le sinus caverneux.Buts : Rapporter un cas de FCC directe post-traumatique et étudier les aspects cliniques, diagnostiques et thérapeutiques de cette pathologie.Observation : Nous rapportons un cas de FCC apparue dans les suites d’un traumatisme craniofacial et survenue chez un homme de 25 ans ayant été victime d’un accident de la voie publique. Le diagnostic a été suspecté devant l’apparition, au 19ème jour d’hospitalisation, d’une exophtalmie unilatérale gauche pulsatile associée à un important chémosis et à une pupille aréflectique. Une artériographie cérébrale pratiquée 9 jours après la constatation de l’exophtalmie a objectivé une large FCC gauche. Une embolisation au moyen de deux ballonnets intravasculaires largables et de l’injection de colle biologique a été réalisée au même temps sans incidents permettant d’obtenir l’occlusion complète de la fistule. L’évolution a été marquée par la régression de l’exophtalmie et du chémosis et par l’amélioration partielle de l’acuité visuelle.Conclusion : Le traitement des FCC est urgent et est principalement basé sur la neuroradiologie interventionnelle. en effet, l’angiographie cérébrale constitue l’examen clé et possède un double intérêt diagnostique et thérapeutique.Mots clés : fistule carotido-caverneuse, traumatisme craniofacial, artériographie cérébrale, embolisation

End-of-fabrication CMOS process monitor

A set of test 'modules' for verifying the quality of a complementary metal oxide semiconductor (CMOS) process at the end of the wafer fabrication is documented. By electrical testing of specific structures, over thirty parameters are collected characterizing interconnects, dielectrics, contacts, transistors, and inverters. Each test module contains a specification of its purpose, the layout of the test structure, the test procedures, the data reduction algorithms, and exemplary results obtained from 3-, 2-, or 1.6-micrometer CMOS/bulk processes. The document is intended to establish standard process qualification procedures for Application Specific Integrated Circuits (ASIC's)

Product assurance technology for procuring reliable, radiation-hard, custom LSI/VLSI electronics

Advanced measurement methods using microelectronic test chips are described. These chips are intended to be used in acquiring the data needed to qualify Application Specific Integrated Circuits (ASIC's) for space use. Efforts were focused on developing the technology for obtaining custom IC's from CMOS/bulk silicon foundries. A series of test chips were developed: a parametric test strip, a fault chip, a set of reliability chips, and the CRRES (Combined Release and Radiation Effects Satellite) chip, a test circuit for monitoring space radiation effects. The technical accomplishments of the effort include: (1) development of a fault chip that contains a set of test structures used to evaluate the density of various process-induced defects; (2) development of new test structures and testing techniques for measuring gate-oxide capacitance, gate-overlap capacitance, and propagation delay; (3) development of a set of reliability chips that are used to evaluate failure mechanisms in CMOS/bulk: interconnect and contact electromigration and time-dependent dielectric breakdown; (4) development of MOSFET parameter extraction procedures for evaluating subthreshold characteristics; (5) evaluation of test chips and test strips on the second CRRES wafer run; (6) two dedicated fabrication runs for the CRRES chip flight parts; and (7) publication of two papers: one on the split-cross bridge resistor and another on asymmetrical SRAM (static random access memory) cells for single-event upset analysis

Fabrication of a novel microsystem for the electrical characterisation of cell array

We have designed and realised a new type of microsystem for the electrical characterisation of arrays of living cells for biomedical diagnostic purposes. We have used deep plasma etching for the fabrication of microholes and micro-fluidic channels in silicon substrates. After oxidation and electrical contact fabrication, these structured silicon wafers have been anodically bonded with Pyrex wafers. The fabrication is completed by the gluing of micro-patterned polyimide foils on top of the silicon. We have tested the electrical characteristics of our microsystems using NaCl salt solutions of various molarities. We believe that our device will open new perspectives for biochemical sensor applications

Electrocardiographic, electrophysiologic, and anatomical features of ventricular tachycardia originating from noncoronary cusp

In this article, we report 2 young patients (a 15-year-old adolescent girl and a 25-year-old man) with drug-refractory palpitations. Admission electrocardiograms showed runs of ventricular tachycardia with left bundle-branch block morphology, left inferior axis, early precordial QRS transition, and positive QRS complex in lead I. In right ventricular mapping, the earliest activation site was found in the His bundle region. Aortic root mapping showed a very early fractionated ventricular signal with large atrial potential and no His potential in the noncoronary cusp region. Radiofrequency energy application in this region resulted in tachycardia termination within 5 to 10 seconds. During a 3- to 6-month follow-up period, the patients remained asymptomatic, and the electrocardiogram showed no ventricular arrhythmias. © 2012 Elsevier Inc

The Degree of Achieving Organizational Rigidity at Umm Al-Qura and Ajloun National Universities: Faculty Members’ Perspective

The paper pinpoints the degree of achieving organizational rigidity at Umm Al-Qura University and Ajloun National University from the faculty members’ viewpoint in line with the faculty, academic rank, and number of years of experience. The nature of the research necessitates using the descriptive survey research approach. A questionnaire adopted as a research instrument is applied to a 410-member sample of (410) randomly designated from the two universities. It is found that the organizational rigidity achievement is of a medium degree with a mean of (3.48). The results also show no statistically significant differences thanks to the variables of the number of years of experience and academic rank. However, it is found that there are differences caused by the faculty variable in favor of scientific faculties. The research recommends activating the methods of evaluating job performance, activating accountability and accounting systems, dividing work at the university according to the competence and experience of workers, and defining the tasks and duties of employees

Isothermal section of the ternary phase diagram U–Fe–Ge at 900 °C and its new intermetallic phases

International audienc

Gene Expression Profiling of Bronchoalveolar Lavage Cells Preceding a Clinical Diagnosis of Chronic Lung Allograft Dysfunction.

BackgroundChronic Lung Allograft Dysfunction (CLAD) is the main limitation to long-term survival after lung transplantation. Although CLAD is usually not responsive to treatment, earlier identification may improve treatment prospects.MethodsIn a nested case control study, 1-year post transplant surveillance bronchoalveolar lavage (BAL) fluid samples were obtained from incipient CLAD (n = 9) and CLAD free (n = 8) lung transplant recipients. Incipient CLAD cases were diagnosed with CLAD within 2 years, while controls were free from CLAD for at least 4 years following bronchoscopy. Transcription profiles in the BAL cell pellets were assayed with the HG-U133 Plus 2.0 microarray (Affymetrix). Differential gene expression analysis, based on an absolute fold change (incipient CLAD vs no CLAD) >2.0 and an unadjusted p-value ≤0.05, generated a candidate list containing 55 differentially expressed probe sets (51 up-regulated, 4 down-regulated).ResultsThe cell pellets in incipient CLAD cases were skewed toward immune response pathways, dominated by genes related to recruitment, retention, activation and proliferation of cytotoxic lymphocytes (CD8+ T-cells and natural killer cells). Both hierarchical clustering and a supervised machine learning tool were able to correctly categorize most samples (82.3% and 94.1% respectively) into incipient CLAD and CLAD-free categories.ConclusionsThese findings suggest that a pathobiology, similar to AR, precedes a clinical diagnosis of CLAD. A larger prospective investigation of the BAL cell pellet transcriptome as a biomarker for CLAD risk stratification is warranted