COMPARISON OF RESULTS AND CALCULATION SPEEDS OF VARIOUS POWER SYSTEM POWER FLOW METHODS SUMMARY

The theoretical part describes basic power flow methods Gauss-Seidel and Newton-Raphson in their practical forms for solving a load flow problem. In practical part, IEEE test 24, 48 and 72 node networks are used to compare basic methods in terms of calculation speed: on execution of one iteration, entire calculation and on given accuracy influence. Also is analyzed optimal acceleration factor for Gauss-Seidel method and convergences of methods. On the end, final conclusions are obtained after analyzing comparison results

COMPARISON OF RESULTS AND CALCULATION SPEEDS OF VARIOUS POWER SYSTEM POWER FLOW METHODS SUMMARY

The theoretical part describes basic power flow methods Gauss-Seidel and Newton-Raphson in their practical forms for solving a load flow problem. In practical part, IEEE test 24, 48 and 72 node networks are used to compare basic methods in terms of calculation speed: on execution of one iteration, entire calculation and on given accuracy influence. Also is analyzed optimal acceleration factor for Gauss-Seidel method and convergences of methods. On the end, final conclusions are obtained after analyzing comparison results

Influence of the acetabular cup position on hip load during arthroplasty in hip dysplasia

Abstract Placement of the acetabular cup during total hip arthroplasty is of great importance because usually every deviation from the ideal centre of rotation negatively influences endoprosthesis survival, polyethylene wear and hip load. Here we present hip load change in respect to various acetabular cup positions in female patients who underwent total hip replacement surgery due to hip dysplasia. The calculation suggests that, in the majority of cases, for every millimeter of lateral displacement of the acetabular cup (relative to the ideal centre of rotation) an increase of 0.7% in hip load should be expected and for every millimeter of proximal displacement an increase of 0.1% in hip load should be expected (or decreased if displacement is medial or distal). Also, for every millimeter of neck length increase, 1% decrease is expected and for every millimeter of lateral offset, 0.8% decrease is expected. Altogether, hip load decreases when the cup is placed more medially or distally and when the femoral neck is longer or lateral offset is used. Résumé Le positionnement de la cupule acétabulaire durant la réalisation d'une prothèse totale de hanche est très important car une déviation de la position idéale du centre de rotation peut influer de façon négative sur la survie, sur l'usure et sur les vecteurs de forces au niveau de la hanche. Nous présentons une étude qui permet de visualiser les vecteurs de forces en fonction des différentes positions de la cupule chez des patients de sexe féminin qui ont bénéficié d'une prothèse totale de hanche mise en place pour dysplasie. Les calculs permettent de penser que dans la majorité des cas chaque millimètre de latéralisation de la cupule augmente de 0,7% la charge au niveau de la hanche et que chaque déplacement proximal l'augmente de 0,1%. Ainsi chaque augmentation millimétrique de la longueur du col peut entraîner une diminution de 1% des forces, de même en ce qui concerne chaque millimètre d'offset latéral qui permet d'obtenir une diminution de 0,8%. En conclusion, les charges diminuent au niveau de la hanche quand la cupule est placée de façon plus médiane ou distale et quand les longueurs du col fémoral ou de l'offset son utilisées

FINANCIAL TRANSMISSION AND STORAGE RIGHTS

The paper presents concepts of Financial Transmission Rights (FTRs) and Financial Storage Rights (FSRs) as key market concepts for alleviating congestion issues in transmission networks. These instruments are in place in markets where prices differ depending on the location/node due to congestions. They serve as a tool for transmission system operators TSO (or independent system operators; ISOs) for eliminating congestions by remunerating entities who make it possible. The paper further discusses different aspects of FTRs, which are traditional financial instruments used to hedge the risk of high cost occurrence associated with transmission congestion. By owning and trading with FTRs, through auction or via bilateral contracts, market participants can gain additional profit. More variable and uncertain power system environment, characterized by high penetration of renewable energy sources (RES), creates potential for storage units to assist TSO/ISO in maximizing social welfare through FSR. As storage has the capability to move energy in time, it can alleviate transmission lines congestion and create profit through intertemporal arbitrage (by load shifting and peak shaving) improving return rate of its investment. These concepts are additionally explained by intuitive examples showing how, when congestion occurs and TSO/ISO awards market participants who own transmission and storage rights, price volatility is reduced

Prvih 100 godina nastave ortopedije na Medicinskom fakultetu Sveučilišta u Zagrebu

In Croatia, hospitals where patients with diseases of the locomotor system were cared for date from more than 100 years ago. However, we consider the beginning of orthopaedics in Croatia to be the year 1908 when Božidar Špišić (1879 - 1957) founded the first Orthopaedic Institute in Zagreb. In 1917, the School of Medicine, University of Zagreb was founded, and when the first students were in their fifth year of studies, the Department of Orthopaedic Surgery was established on December 15, 1922, and Božidar Špišić became an Assistant Professor. From that date until today, Orthopaedics has been an independent department within the School of Medicine. The Department of Orthopaedic Surgery was primarily established for the education of medical students. Another important activity of the Department was the training of orthopaedic surgeons and specialists in overlapping fields with orthopaedics. In 1973, the department made a program of postgraduate studies in orthopaedics. The department also participated in postgraduate studies of other professions overlapping with orthopaedics and held numerous post-graduate courses and continuous medical education for doctors. Also, the department organised both domestic and international meetings, symposia, and congresses. Within the scientific post-graduate and doctoral studies, the Department of Orthopaedic Surgery members are lecturers in many courses. This article presents the work and development of the Department of Orthopaedic Surgery in the first 100 years of orthopaedics education at the School of Medicine, University of Zagreb and clinical work as a part of the University Hospital Centre Zagreb. It is a presentation of time periods under nine heads of the department, starting from Professor Božidar Špišić all to the current head Professor Domagoj Delimar.Premda su i ranije u Hrvatskoj postojale bolnice u kojima su se zbrinjavali bolesnici s bolestima i ozljedama lokomotornog sustava, organiziranim početkom rada ortopedije u Hrvatskoj smatra se 1908. godina kada je Božidar Špišić (1879. - 1957.) u Zagrebu osnovao prvi Ortopedski zavod na slavenskom jugu. 1917. godine utemeljen je Medicinski fakultet Sveučilišta u Zagrebu, i kada prvi studenti dolaze na petu godinu studija medicine, utemeljuje se i Katedra za ortopediju, a dr. Božidar Špišić postaje docent 15. 12. 1922. godine. Od tog datuma pa sve do danas ortopedija je samostalan predmet i Katedra u okviru Medicinskog fakulteta. Katedra za ortopediju prvenstveno je osnovana za edukaciju studenata medicine, dok je slijedeća značajna djelatnost Katedre za ortopediju bila i ostala izobrazba specijalista ortopeda i specijalista struka koje se preklapaju s ortopedijom. 1973. godine Katedra za ortopediju započela je provoditi plan i program postdiplomskog studija iz ortopedije, a održava i mnogobrojne postdiplomske tečajeve te tečajeve trajnog usavršavanja liječnika. Također, Katedra organizira domaće i međunarodne sastanke, simpozije i kongrese. Na znanstvenom postdiplomskom i doktorskom studiju članovi Katedre za ortopediju voditelji su mnogih kolegija. Prikaz rada i razvoja Katredre za ortopediju u proteklih 100 godina djelovanja u okviru Medicinskog fakulteta Sveučilišta u Zagrebu i Klinike za ortopediju Kliničkog bolničkog centra Zagreb podijeljen je na više vremenskih odsječaka, počevši od prvog pročelnika profesora Božidara Špišića sve do današnjeg, devetog pročelnika Katedre za ortopediju i predstojnika Klinike za ortopediju Kliničkog bolničkog centra Zagreb profesora Domagoja Delimara

PhysioSoft – An Approach in Applying Computer Technology in Biofeedback Procedures

The paper presents description of original biofeedback computer program called PhysioSoft. It has been designed on the basis of the experience in development of biofeedback techniques of interdisciplinary team of experts of the Department of Health Psychology of the University of Applied Health Studies, Faculty of Electrical Engineering and Computing, University of Zagreb, and »Mens Sana«, Private Biofeedback Practice in Zagreb. The interest in the possibility of producing direct and voluntary effects on autonomic body functions has gradually proportionately increased with the dynamics of abandoning the Cartesian model of body-mind relationship. The psychosomatic approach and studies carried out in the 50-ies of the 20th century, together with the research about conditioned and operant learning, have proved close inter-dependence between the physical and mental, and also the possibility of training the individual to consciously act on his autonomic physiological functions. The new knowledge has resulted in the development of biofeedback techniques around the 70-ies of the previous century and has been the base of many studies indicating the significance of biofeedback techniques in clinical practice concerned with many symptoms of health disorders. The digitalization of biofeedback instruments and development of user friendly computer software enable the use of biofeedback at individual level as an efficient procedure of a patient’s active approach to self care of his own health. As the new user friendly computer software enables extensive accessibility of biofeedback instruments, the authors have designed the PhysioSoft computer program as a contribution to the development and broad use of biofeedback

Ulnar shortening osteotomy after distal radius fracture malunion: review of literature

Malunion of distal radius fracture is often complicated with shortening of the radius with disturbed radio- ulnar variance, frequently associated with lesions of triangular fibrocartilage complex and instability of the distal radioulnar joint. Positive ulnar variance may result in wrist pain located in ulnar part of the joint, limited ulnar deviation and forearm rotation with development of degenerative changes due to the overloading that occurs between the ulnar head and corresponding carpus. Ulnar shortening osteotomy (USO) is the standard procedure for correcting positive ulnar variance. Goal of this procedure is to minimize the symptoms by restoring the neutral radio - ulnar variance. In this paper we present a variety of surgical techniques available for ulnar shorthening osteotomy, their advantages and drawbacks. Methods of ulnar shortening osteotomies are divided into intraarticular and extraarticular. Intraarticular method of ulnar shortening can be performed arthroscopically or through open approach. Extraarticular methods include subcapital osteotomy and osteotomy of ulnar diaphysis, which depending on shape can be transverse, oblique, and step cut. All of those osteotomies can be performed along wrist arthroscopy in order to dispose and treat possibly existing triangular fibrocartilage complex injuries. At the end we described surgical procedures that can be done in case of ulnar shorthening osteotomy failure

Impact of various hydro power generation scenarios on energy balance and power markets in SEE region

This paper presents electricity power generation capacities in South East Europe (SEE). Due to a high share of hydro power generation, hydrology has a major influence on energy balance and power markets in SEE. Power markets are facing the impact of a rising number of renewable energy generation facilities. This paper describes influences of energy availability on power markets and energy generation within three hydrological scenarios (dry, normal and wet scenario). Short-term electricity prices are analyzed in terms of production and consumption on three major power exchanges in Romania, Hungary and Slovenia. Findings demonstrate influences of weather conditions on power markets in SEE through energy production, security of supply and risks facing power producers

LSQ DC 123 IIR algoritam za blokadu diferencijalne zaštite bloka i otkrivanje zemljospoja generatora

U radu je prikazan LSQ DC 123 IIR algoritam, razvijen na Fakultetu elektrotehnike i računarstva Sveučilišta u Zagrebu, koji je dobiven iz originalnog LSQ IIR algoritma. Glavna namjena algoritma je blokada numeričkih zaštitnih uređaja pri magnetiziranju energetskih transformatora spojenih u bloku s generatorom i stopostotna zaštita generatora od zemljospoja. Analiziran je rad LSQ DC 123 IIR algoritma te je prikazano učinjeno poboljšanje u odnosu na LSQ algoritam koji je u praktičnim uvjetima neupotrebljiv. LSQ DC 123 IIR algoritam računa istosmjernu komponentu signala te amplitude prvog, drugog i trećeg harmonika iz mjerenih valnih oblika napona i struja. Uz amplitudne vrijednosti algoritam daje i fazne, kao što su kutovi osnovnog, drugog i trećeg harmonika između svih mjerenih valnih oblika električnih signala. Iz algoritma je također moguće dobiti i vremensku konstantu istosmjerne prigušujuće komponente koja se javlja pri kratkom spoju. Iz dobivenih vrijednosti se donose zaključci prema tome je li nastupio kvar ili je potrebno blokirati proradu numeričke zaštite bloka generator-transformator