Calculation of Electromagnetic Fields in Electrical Machines using Finite Elements Method

Finite Elements Method is a contemporary numerical method for determination of distribution of electromagnetic fields inside different objects. In this paper three different induction motors will be analyzed : Solid Salient Poles Synchronous Motor, product of company MAWDSLEY, Single Phase Shaded Pole Motor, product of company Micron-Tech and Induction Squirrel Cage Motor, product of company Koncar. In all analyzed motors distribution of electromagnetic field and magnetic flux density are calculated using two different approaches: magneto-static at zero herz frequency and magneto-dynamic at fifty herz frequency. Further on, calculation of different motor parameters such as magnetic flux density distribution in motor air gap at different operating regimes is performed and adequate conclusion are derived. Keywords: Finite Elements Method, Magnetic Fields Calculation, Induction Motor

ARTES LIBERALES

Pojam, pravno reguliranje, kao i pitanje koji je tip intelektualne djelatnosti spadao u artes liberales sporni su kako kod rimskih pravnika tako i u romanističkoj znanosti. Za razliku od starije romanističke znanosti, u kojoj je uglavnom smatrano da su usluge slobodnih profesija bile predmetom ugovora o nalogu (mandatum), u suvremenoj romanističkoj znanosti postoje oprečna mišljenja o tom problemu. Kreću se od stava da su regulirane pravilima mandata, najma ili inominatnog kontrakta, preko mišljenja da je upravo u toj oblasti besplatno djelovanje jedne stranke za drugu smješteno izvan ugovorne sfere. Autorica zaključuje da je rimsko shvaćanje djelatnosti obuhvaćenih terminom artes liberales bilo tijekom vremena podložno promjenama u ovisnosti o društvenim shvaćanjima, ali se uvijek zahtijevalo da ars liberalis - formalno besplatno, obavlja u slobodi rođeni Rimljanin. Iz tog razloga takva djelatnost nije mogla biti predmetom ugovora locatio conductio, ali ni mandata jer se u vrelima ne spominje actio mandati kao tužba kojom je nositelj slobodne profesije mogao tužiti, ili biti tužen. Krug artes liberales nije predstavljao pravnu kategoriju i sama kvalifikacija najčešće nije ovisila o fizičkoj ili intelektualnoj naravi posla nego o činjenici obavlja li ga slobodna osoba ili rob i na kojoj osnovi.The notion, the legal regulation as well the question, what sort of the intellectual labour should be regarded as ars liberalis, are controversial with Roman jurists as well as in Roman doctrine. In distinction from the older doctrine, that mainly deemed these services under a contract of mandate (mandatum), the contemporary science comprehends a lot controversies: the holders of the liberal professions (artes liberales) could engage under a contract of mandate, or contract of hire (locatio conductio), or the artes liberales were rendered under an innominate contract. Also there exists the opinion correspondingly on which the services as such were not the object of the contract. Strictly the activities which could be regarded as worthy of a free man are comprised by the term artes liberales. Since the Romans made a great difference between intellectual and manual labour, and the aristocratic perception had equalized the salaried labour with the slavishly position, the author concludes that artes liberales couldn’t be the object of the contract of locatio conductio. Also, these activities were not carried out on the basis of a contract of mandate. In the roman sources there isn’t any evidence that the contract of mandate covered the sector of these services and that actio mandati could be used to claim. In fact, at the basis of the evaluation of these services lies the social criterion, that was modified during the time. Pursuant to that, the sector of the artes liberales didn’t imply the unique legal category and its evaluation was depending on the basis of the carryung out and the fact whether this labour had made by a free man or by a slave.Der Begriff, die rechtliche Regelung ebenso wie die Frage, welche Art von geistiger Arbeit als ars liberalis zu betrachten wäre, sind strittig sowohl bei den römischen Juristen als auch in der romanistischen Wissenschaft. Während die ältere Romanistik meistens die Meinung verfechtete, dass diese Dienste tatsächlich unter das Mandat subsumiert wurden, bestehen in der neuerer Wissenschaft viele Kontroversen: die Erbringer von artes liberales konnten sich aus dem Auftrag (mandatum), oder aus dem Mietvertrag (locatio conductio) oder aus dem Innominatkontrakt verpflichten. Es besteht auch die Meinung, nach der es sich hier um die ausservertragliche Sphäre handelt. Unter artes liberales verstand man solche Tätigkeiten, die eines freien Menschen würdig waren. Da in der römischen Welt ein grundsätzlicher Unterschied zwischen geistiger und physischer Arbeit bestand, und die aristokratische Anschauungsweise die bezahlte Arbeit praktisch dem Sklavenzustand gleichsetzte, kommt die Autorin zum Schlusse, dass artes liberales nicht Gegenstand des Arbeits- oder Werkvertrages sein konnten. Diese Tätigkeiten, die nach der römischen Auffassung unter die artes liberales eingereiht wurden, konnten auch nicht Gegenstand des Auftrags sein. In den römischen Quellen gibt es keinen Beweis, dass die artes liberales durch das Auftragsrecht reguliert wurden, oder dass eine actio mandati angestrengt werden könnte. Eigentlich lag der Bewertung der Tätigkeiten, die man als artes liberales qualifizierte, keine juristische, sondern eine gesellschaftliche Beurteilung zu Grunde, die sich im Laufe der Zeit geändert hat. Dementsprechend bedeutete der Kreis der artes liberales keine eindeutige juristische Kategorie, und die Qualifizierung selbst war von der Tatsache abhängig, ob diese Arbeit von einem freien Menschen oder von einem Sklaven, und auf welcher Grundlage verrichtet wurde.La nozione, la disciplina giuridica, come pure l\u27interrogativo sul genere di attività intellettuale che veniva annoverato nelle artes liberales sono controversi sia per i giusromanisti, che per la scienza romanistica. A differenza della scienza romanistica più risalente nella quale si riteneva principalmente che le prestazioni delle libere professioni fossero oggetto del contratto di mandato (mandatum), nella scienza romanistica contemporanea sussistono convincimenti diversi circa detta questione; tali opinioni vanno dalla posizione secondo cui la materia è soggetta alla disciplina del mandato, della locazione oppure dal contratto innominato, attraverso l\u27 opinione in base alla quale proprio in questo ambito l\u27operato gratuito di una parte nei confronti dell\u27altra vada collocato al di fuori della sfera contrattuale. L\u27autrice perviene alla conclusione che nel tempo la concezione romanistica delle attività intese con il termine artes liberales è stata soggetta a cambiamenti in relazione alle diverse concezioni sociali, benché in ogni epoca si pretendesse che l\u27ars liberalis – formalmente gratuita, venisse eseguita da un romano nato libero. Per questo motivo detta attività non poteva essere oggetto di un contratto di locatio conductio, come nemmeno di mandato, poiché nelle fonti non viene fatta menzione dell\u27actio mandati, quale azione mediante la quale il titolare della libera professione potesse agire in giudizio od essere citato. Le artes liberales non costituivano una categoria giuridica, né la qualificazione medesima dipendeva dalla natura fisica od intellettuale dell’opera; bensì dalla circostanza se la stessa venisse eseguita da una persona libera o da uno schiavo e su quali basi

Myositis Ossificans of the temporalis muscle : case report

Los autores presentan un caso poco frecuente de miositis osificante del músculo temporal en un paciente varón de 51 años que se manifiesta con limitación de la apertura oral, con masa firme y dura en la fosa temporal derecha. La tomografia axial computerizada (TC) reveló una masa de densidad ósea localizada en la región temporal derecha, que unía el hueso temporal derecho con la apófisis coronoides y una imagen de pseudo-articulación en su porción media. La miositis osificante traumática es un tumor benigno que se localiza frecuentemente en las extremidades de los adolescentes. Los casos en el esqueleto craneofacial son raros. En esta localización, los músculos masetero y esternocleidomastoideo son los más frecuentemente afectados. Las características clínico patológicas de la miositis osificante pueden imitar otros tumores de los tejidos blandos, por lo que se requiere un cuidadoso diagnóstico diferencial. Histológicamente, la actividad osteoblástica asemeja a veces a un osteosarcoma, que requiere establecer el diagnóstico diferencial entre ambas entidades. En nuestro caso, el tratamiento quirúrgico, mediante abordaje combinado retromolar y hemicoronal, fue el elegido

Transient analysis of induction motor using different simulation models

Squirrel cage induction motors have wide range of applications in many industrial drive systems due to their simple construction, robust design and low operational costs. Their application becomes even wider as a result of implementation of voltage inverters providing very good speed-torque control characteristics. In this paper a dynamic behaviour of a squirrel cage induction motor type 2AZ 155-4, produced by Rade Koncar, is analysed. The motor has the following rated data: voltage (Δ/Y) 220/380 V, number of poles 2p=4, rated current 8,7/5 A, power factor cosϕ=0,81, rated speed nn=1410 rpm, frequency 50 Hz. The first simulation motor model, supplied from a symmetrical power supply, is developed in MATLAB/Simulink [1]. The following dynamic motor characteristics, such as: speed characteristic, electromagnetic torque characteristic and current were obtained from this model. Than the analysis is extended with a simulation model of the motor fed by a voltage inverter. In this case the motor transient speed, current and electromagnetic torque characteristics are obtained, for rated frequency as well as for frequencies lower and higher than the rated one. The results obtained from the simulation in MATLAB/Simulink are compared and verified with the results from the second simulation model developed in the software program PSIM. Distribution of magnetic flux density inside the motor cross section is gained by application of the Finite Elements Method (FEM) for all motor operation regimes. Simulatio

The role of the agreement on Trade Related Aspects of Intellectual Property Rights (TRIPS) in the system intellectual property protection

The Agreement on Trade Related Aspects of Intellectual Property Rights is one of the recent treaties in the system of intellectual property protection. This agreement represents an annex to the Agreement Establishing the World Trade Organization and is not in the system of the World Intellectual Property Organization. According to the TRIPS Agreement, protection of intellectual property should contribute to the promotion of technological innovation, transfer and dissemination of technologies for the mutual benefit of producers and users of technological knowledge in ways that incite social and economic development, as well as balancing the rights and obligations. TRIPS contains some of the principles and clauses that are specific to international trade agreements, such as most-favored-nation clauseand it gave the definition of each of the industrial property rights. These definitions will contribute to the harmonization of national legislation in this field.Unlike earlier treaties, TRIPS contains detailed provisions relating to the enforcement of intellectual property rights.Thanks to the mechanism of sanctions under the World Trade Organization, TRIPS became an umbrella agreement in the system of intellectual property protection

Successful treatment of refractory gastrointestinal bleeding by systemic (oral) ankaferd blood stopper in a patient with Glanzmann thrombasthenia

Background: Glanzmann Thrombasthenia (GT) is a genetic platelet dysfunction and a life threatening disease. Ankaferd Blood Stopper (ABS) is a topical hemostatic agent of herbal origin which has been recently made available for clinical use. Its hemostatic effect is independent from blood clotting factors and occurs as a result of the aggregation of focal red blood cells by an encapsulated protein web. Case Report: In this paper, a patient with GT is presented in whom 3 months of gastrointestinal bleeding refractory to all medical therapies was controlled within a short time of using oral ABS. Conclusion: The difference between this patient and other cases presented in the medical literature is the oral use of ABS. Thus, this patient may contribute to the medical community in showing the safety and efficacy of systemic (oral) ABS in patients with disorders of coagulation. However, there is a need for more patient experiences. © Trakya University Faculty of Medicine

CLINICAL TRIALS IN DEVELOPING COUNTRIES - ETHICAL CONSIDERATIONS

When designing clinical trial or considering decision to take part in particular clinical trial as investigators, even before submission to responsible Central Ethic Committee, we always make certain private assessment about ethical justification of this clinical trial. When making assessment if any clinical trial is ethically justifiable, there should make no difference in which country this clinical trial will be executed. Physicians coming from developing countries must ensure that patient population of developing countries is not misused in any ethically questionable clinical trial. There must be careful assessment of clinical protocols by various independent local advisory committees (e.g. hospital review boards, hospital drug committees, hospital administration and whatever is applicable) to exclude the possibility that only one person or one group of people has concentrated power to make decisions for entire country. Many times physicians/clinical researchers from developing countries are faced with the criticisms that they are not of the same quality as physicians from developed countries and that they can be easily bribed by sponsors, which are based on the prejudice that any clinical trial can be executed in developing countries, no matter of quality or risks for patients. Physicians coming from developing countries must ensure that patient population of developing countries is not misused in any ethically questionable clinical trial

Optic nerve head drusen: same presentation, different workup

Objective/Purpose: To report two young patients with optic nerve head drusen in wich one was interpreted initially as pappiledema. Discuss the OCT and the autofluorescence retinography optic nerve head drusen characteristics. Materials/Patients: Patient 1: A 10-year-old boy who was noted at follow-up ophthalmology consultation to have an abnormal optic nerve head. He refers a recent episode of neck pain. His past medical history is irrelevant. He has a strabismic amblyopia due to anisometropia. Fundoscopy showed bilateral disc enlargement that wasn t describe in previous consultation being interpreted as papilledema. Observation by Neuropediatry as well as the CT scan were unremarkable. Bilateral optic disc drusen were confirmed on B-scan ultrasonography, autofluorescence retinography and retinal nerve fiber layer on Stratus- OCT®. Patient 2: A 14-year-old girl went on a routine ophtalmology examination. Her past medical and ocular history were irrelevant. On examination visual acuity was 10/10 in both eyes. Fundoscopy showed bilateral disc enlargement being interpreted as optic nerve head drusen. Bilateral optic nerve head drusen were confirmed on B-scan ultrasonography, autofluorescence retinography and retinal nerve fiber layer on Stratus-OCT®. Methods: B-scan ultrasonography, autofluorescence retinography and Stratus-OCT imaging were obtained. Results and Conclusion Both patients were assymptomatic. With non-invasive readily available exams, such as ultrasonography and OCT practioners must rule out optic nerve head before costly and invasive exams , even when there is a history and fundoscopy highly suggestible of papilledema. Optic nerve head drusen were first described in 1868 by Liebreich. They are mostly bilateral and assymptomatic, although some degree of visual field defect can be shown. Most cases of pseudopapilledema are due to the presence of optic nerve head drusen, there are some clinical characteristics that can help to differenciate one from another but the use of recent technology is needed to confirm the diagnosis

Примена на лого контролер во управување на машина абкантпреса СTO-400 од апспект на зголемување на доверливоста и безбедноста на погонот

Современите програмибилни логички контролери се сé повеќе присутни во електормоторните погони допринесувајќи за поголема стабилност и доверливост на истите. Во трудот е прикажана замената на релејното-контакторско (аналогно) управување со дигитално преку имплементација на програмибилен контролер од фамилијата LOGO на производителот Siemens на машина абкантпреса СТО-400 инсталирана во АД „ФАКОМ“. Трудот дава опис на софтверското решение изработено во програмот LOGO Soft Comfort V7.0. преу описот на различните режими на работа на пресата со што се добива увид и во функционалноста на логичкиот котролер LOGO 230 RCE. Програмирањето на контролерот е направено со помош на Lаdder дијаграм, чија симулција треба успешно да заврши за да истиот може да се вчита во програмибилниот контролер. Двете абкантпреси се веќе подолго време инсталирани во работната еднициа „Производство„ при АД „ФАКОМ“ со намена да работата во тандем режим на работа, односно при синхронизација на двата хидраулични системи. Принципот на работа тандем бил неуспешен уште од самото пуштање во работа на машините поради лошата синхронизација на двата толчника кои се управуваат хидраулично. Со ова современо дигитално управување на двете абкантпреси, се врши подготвка за нивна синхронизација и можност за работење во тандем врска. Покрај тоа се зголемува и доверливоста и безбедноста на работата на машините преку намалување на бројот на дефекти кои се последица на дотраениот релејно-контакторски систем на управување. Со модренизација на управувањето на двете преси се зголемува стабилноста во работата, дијагностицирањето и одстранувањето на дефектите се врши многу побрзо и полесно со што работата на машината може да се следи попрегледно и поточно