Critical stress of oval foil winding with epoxy coated insulation determined using measured equivalent modulus of elasticity

In the distribution transformers design oval windings are used due to economic advantages. On the other hand, such windings are more susceptible to radial forces in a short circuit. A diamond dotted paper with an epoxy coating is used in order to increase the stiffness of the winding. Despite that, winding failure may occur during the short circuit, e.g. buckling of inner winding. Because of a very thin foil conductor (typically 0.5–2 mm), the most critical is inner low voltage foil winding which can collapse due to radial forces at stresses far below the elastic limit of conductor material. This paper shows an analytical approach to the calculation of critical stress in inner oval foil winding with epoxy coated insulation. Critical stress was calculated using the equation for free buckling of round winding. Equivalent Young\u27s modulus of elasticity was obtained experimentally from the testing of the sample model loaded with bending force on a tensile test machine. A total of 12 test samples were formed from aluminium foil conductor and diamond dotted paper and cured at the temperature of 105°C. The results were successfully verified on distribution transformers subjected to short circuit withstand tests

Constrained field-oriented control of permanent magnet synchronous machine with field-weakening utilizing a reference governor

This paper presents a complete solution for constrained control of a permanent magnet synchronous machine. It utilizes field-oriented control with proportional-integral current controllers tuned to obtain a fast transient response and zero steady-state error. To ensure constraint satisfaction in the steady state, a novel field-weakening algorithm which is robust to flux linkage uncertainty is introduced. Field weakening problem is formulated as an optimization problem which is solved online using projected fast gradient method. To ensure constraint satisfaction during current transients, an additional device called current reference governor is added to the existing control loops. The constraint satisfaction is achieved by altering the reference signal. The reference governor is formulated as a simple optimization problem whose objective is to minimize the difference between the true reference and a modified one. The proposed method is implemented on Texas instruments F28343 200 MHz microcontroller and experimentally verified on a surface mounted permanent magnet synchronous machine

Izračunavanje parametara motora s umetnutim permanentnim magnetima metodom konačnih elemenata

A method for calculation of parameters of an interior permanent magnet (IPM) motor at any operating point using 2-D finite element method is presented. This approach is suited to be used in the design stage where it is necessary to determine the motor parameters, namely inductances, which are simultaneously a function on motor dimensions and terminal voltage constraints. An analytical technique based on a 3-D geometric model of the end winding region in which each coil is modeled as a set of serially connected straight filaments has been used for calculation of the end winding leakage inductance. The calculation of the mutual inductance of the end coils is based on the multiple solutions of the Neumann integral. This approach to calculation of motor parameters has been applied in the design of a 1.65 kW IPM motor for which a prototype has been built and tested.Prikazana je metoda proračuna parametara motora s umetnutim permanentnim magnetima u bilo kojoj radnoj točki korištenjem dvodimenzionalne metode konačnih elemenata. Metoda je prilagođena korištenju u fazi projektiranja motora gdje je potrebno odrediti parametre motora, posebice induktivitete, koji su istovremeno funkcija geometrijskih dimenzija motora i ograničenja naponskog izvora napajanja. Za proračun reaktancije glava namota korištena je analitička metoda bazirana na trodimenzionalnom modelu čeonog prostora motora u kojem je svaki svitak modeliran kao skup međusobno povezanih tankih ravnih linija. Proračun međuinduktiviteta svitaka u glavi namota baziran je na rješenju Neumannovog integrala. Navedeni pristup proračunu parametara je primijenjen na motoru s umetnutim magnetima snage 1,65 kW za koji je napravljen i ispitan prototip

Seroprevalencija meadi-visna virusa i procjena rizičnih čimbenika u populaciji ovaca u jugozapadnoj Hrvatskoj

The objective of this cross-sectional study was to detect the presence of maedi visna virus (MVV) infections in sheep in three counties in southwestern Croatia: Istria County, Primorje-Gorski Kotar County and Lika-Senj County, and to estimate the influence of geographical location, breed, age and gender as risk factors on the prevalence rate. A total of 460 randomly selected sheep were tested using a commercially available ID Screen® MVV/CAEV Indirect screening test, VISNAS-5P (ID.VET, Grabels France) for detection of antibodies against the Maedi-Visna virus. The prevalence rate for the entire population was 10.00 % (95 % 7.26 - 12.74 %), The highest seroprevalence of MVV was found in Istria County (19.02%, CI 95% 13.35 –24.70%), followed by Lika-Senj County (5.43 %, CI 95 % 2.17- 8.70) and Primorje-Gorski Kotar County (1.07 %, CI 95 % -1.03 – 3.17) (P<0.01). When comparing the seroprevalence among breeds, statistically significant differences were observed. The largest number of positive sheep was found in the following breeds: Istrian Pramenka (22.97%, CI 95% 13.39 - 32.55%), Jezersko-Solcava sheep (23.53%, CI 95% 11.89 - 35.17%%), Pramenka (13.16%, CI 95% 2.41 - 23.91%) and Lika sheep (9.78%, CI 95% 3.71- 15.85%). Prevalence rates in other examined breeds (Krk sheep, Pag sheep and Romanov sheep) were lower than 2 % (P<0.01). No statistically significant differences in seroprevalence between sex and age were found. According to risk estimation, the main risk factors were found to be geographical location and breed. In Istria County, seroprevalence was 4.77 ( CI 95 % 2.67 – 8.54) higher than in other examined areas (OR = 5.66, CI 95 % 2.97-10.79) (P<0.01). As for breeds, significant differences were observed between Jezersko-Solcava sheep and Lika sheep (OR = 2.84, CI 95% 1.13-7.14) and Istrian Pramenka in relation to Pag sheep (OR 22.51,, CI 95% 16.99-119.73), Krk sheep (OR 19.53, CI 95% 5.80-108.27), and Lika sheep (OR 2.35, CI 95% 1.17-6.47). This cross-section study indicates the circulation of MVV in this sheep population in Croatia, and represents the first research into the risk factors for MVV in sheep in southwestern Croatia.Cilj istraživanja bio je otkriti prisutnost infekcija virusom maedi visna (MVV) kod ovaca u tri županije u jugozapadnoj Hrvatskoj - Istarskoj, Primorsko-goranskoj i Ličko-senjskoj te procijeniti utjecaj geografske lokacije, pasmine, dobi i spola kao čimbenike rizika za stopu prevalencije. Ukupno je pregledano 460 nasumično odabranih ovaca postupkom ELISE ID Screen® MVV/CAEV indirektnog testa VISNAS-5P za otkrivanje protutijela protiv virusa maedi-visna. Stopa prevalencije za cijelu populaciju iznosila je 10,00% (CI 95% 7,26 - 12,74%). Najveća seroprevalencija MVV utvrđena je u Istarskoj županiji (19,02%, CI 95% 13,35–24,70%), zatim u Ličko-senjskoj županija (5,43%, CI 95% 2,17-8,70) i Primorsko-goranska županija (1,07%, CI 95% -1,03 - 3,17) (P<0,01). Usporedbom seroprevalencije između pasmina uočene su statistički znakovite razlike. Najveći broj pozitivnih ovaca nađen je kod istarske ovce (22,97%, CI 95% 13,39 - 32,55%), zatim jezersko-solčavske ovce (23,53%, CI 95% 11,89 - 35,17 %%), pramenke (13,16% , CI 95% 2,41 - 23,91%) i ličke pramenke (9,78%, CI 95% 3,71 - 15,85%). Stopa prevalencije u ostalih istraženih pasmina (krčka ovca, paška ovca i romanovska ovca) bila je niža od 2% (P<0,01). Statistički znakovite razlike u seroprevalenciji prema spola i dobi nisu ustanovljene. Kao glavni čimbenici rizika utvrđeni su zemljopisni položaj i pasmina. U Istarskoj županiji seroprevalencija je bila 4,77 (CI 95% 2,67 - 8,54) puta veća nego u ostalim istraženim područjima (OR = 5,66, CI 95% 2,97-10,79) (P<0,01). Uočene su znakovite razlike između jezerskosolčavske ovce i ličke pramenke (OR = 2,84, CI 95% 1,13-7,14) te istarske ovce u odnosu na pašku ovcu (OR 22,51 , CI 95% 16,99-119,73), krčku ovcu (OR 19,53, CI 95% 5,80-108,27) i ličku pramenku (OR 2,35, CI 95% 1,17-6,47). Rad predstavlja prvo istraživanje seroprevalencije i rizičnih čimbenika za MVV ovaca u jugozapadnoj Hrvatskoj. Rezultati ukazuje na prisutnost MVV infekcije te na važnost daljnjeg istraživanja bolesti u Hrvatskoj

Treatment of spastic knee contractures with botulinum toxin and physioteraphy in patients with severe traumatic brain injury

Spazam kao pozitivni simptom oštećenja gornjih motoneurona uslijed teške traumatske ozljede mozga, ukoliko se ne počne liječiti rano nakon oštećenja neurona, može biti uzrok kontraktura. U ovoj je prospektivnoj studiji istraživano djelovanje fizioterapije i botulinum toksina A u liječenju kontraktura koljena u pacijenata kod kojih sama fizioterapija nije dovela do smanjenja kontraktura i tonusa mišića. U studiju je bilo uključeno 26 pacijenata koji su imali kontrakturu u jednom ili oba koljena (ukupno 30 koljena), a kod kojih se tonus mišića i kontraktura koljena nisu umanjili nakon tromjesečne fizioterapije. Nakon aplikacije botulinum toksina A i nastavka fizioterapije, kod pacijenata je došlo do značajnoga poboljšanja pokretljivosti u koljenu, kao i do smanjenja spazma u mišićima u koje je bio apliciran botulinum toksin A. Primjenom botulinum toksina A i fizioterapijom mogu se značajno umanjiti kontrakture koljena koje su bile otporne na fizioterapiju, čime je izbjegnuto operativno liječenje i poboljšana aktivnost i participacija bolesnika u aktivnostima svakodnevnoga života.Spasm as a positive symptom of upper motor neuron damage due to severe traumatic brain injury, if not treated early after brain damage can cause contractures. This prospective study investigated the effect of physiotherapy and Botulinum toxin A in treating knee contractures in patients in whom physical therapy did not lead to reduction in contracture and reduced muscle tone. The study included 26 patients who had a contracture in one or both knees (a total of 30 knees), and in which the muscle tone and contracture of the knee have not been reduced after three months of physiotherapy. After application of Botulinum toxin A and continuing physiotherapy improvement in knee mobility and decrease in muscle spasms in muscles has been observed. The application of Botulinum toxin A and physiotherapy can significantly reduce knee contractures that were not responding to physiotherapy, thus sparing surgical treatment and improving patient activity as well as participation in daily living activities

Long-term Follow-up of Blood Pressure in Family Members of Soldiers Killed During the War in Bosnia and Herzegovina

Aim: To asses prevalence of essential arterial hypertension in family members of soldiers killed in 1992-1995 war in Bosnia and Herzegovina. Methods: The study enrolled 1144 subjects who lost a family member in the war and 582 of their close neighbors who experienced no such loss. Data on their medical history and habits were collected, and their blood pressure was recorded in 1996 and 2003. Arterial hypertension was defined as systolic blood pressure ≥140 mm Hg (≥130 mm Hg in patients with diabetes mellitus), or diastolic blood pressure ≥90 mm Hg (≥80 mm Hg in patients with diabetes mellitus), or taking antihypertensive therapy. Additional laboratory and clinical tests were performed in subjects with hypertension. Results: The prevalence of hypertension at both time points was higher in the group with a killed family member than in the group without the loss (55.1% vs 42.1%, P<0.001 in 1996, and 50.7% vs 39.0%, P<0.001 in 2003, respectively). However, there was also a significant decrease in the prevalence of hypertension in the group with the loss in 2003 (P<0.001), but not in group without the loss. Posttraumatic stress disorder (PTSD), smoking, and alcohol consumption were more prevalent in the group with a killed family member, but not cholesterol and triglyceride blood concentrations. In both groups, hypertension was more prevalent in subjects with PTSD and smoking or drinking habit. Proportion of subjects with hypertension who smoked and used alcohol was similar in both groups. Proportion of subjects with hypertension who did not smoke or drink was higher in the group with the loss (51.1% vs 36.7%, P<0.001; 46.2% vs 35.0%, P=0.006, respectively). Conclusion: This study showed higher prevalence of hypertension in family members of killed soldiers, regardless of the presence of other cardiovascular risk factors. Only the stress of mourning was associated with higher prevalence of hypertension. Over time, proportion of hypertensive subjects with the loss decreased in the group with killed family member, further suggesting that at least a part of their hypertension might have been of psychological origin

Treatment of spastic knee contractures with botulinum toxin and physioteraphy in patients with severe traumatic brain injury

Spazam kao pozitivni simptom oštećenja gornjih motoneurona uslijed teške traumatske ozljede mozga, ukoliko se ne počne liječiti rano nakon oštećenja neurona, može biti uzrok kontraktura. U ovoj je prospektivnoj studiji istraživano djelovanje fizioterapije i botulinum toksina A u liječenju kontraktura koljena u pacijenata kod kojih sama fizioterapija nije dovela do smanjenja kontraktura i tonusa mišića. U studiju je bilo uključeno 26 pacijenata koji su imali kontrakturu u jednom ili oba koljena (ukupno 30 koljena), a kod kojih se tonus mišića i kontraktura koljena nisu umanjili nakon tromjesečne fizioterapije. Nakon aplikacije botulinum toksina A i nastavka fizioterapije, kod pacijenata je došlo do značajnoga poboljšanja pokretljivosti u koljenu, kao i do smanjenja spazma u mišićima u koje je bio apliciran botulinum toksin A. Primjenom botulinum toksina A i fizioterapijom mogu se značajno umanjiti kontrakture koljena koje su bile otporne na fizioterapiju, čime je izbjegnuto operativno liječenje i poboljšana aktivnost i participacija bolesnika u aktivnostima svakodnevnoga života.Spasm as a positive symptom of upper motor neuron damage due to severe traumatic brain injury, if not treated early after brain damage can cause contractures. This prospective study investigated the effect of physiotherapy and Botulinum toxin A in treating knee contractures in patients in whom physical therapy did not lead to reduction in contracture and reduced muscle tone. The study included 26 patients who had a contracture in one or both knees (a total of 30 knees), and in which the muscle tone and contracture of the knee have not been reduced after three months of physiotherapy. After application of Botulinum toxin A and continuing physiotherapy improvement in knee mobility and decrease in muscle spasms in muscles has been observed. The application of Botulinum toxin A and physiotherapy can significantly reduce knee contractures that were not responding to physiotherapy, thus sparing surgical treatment and improving patient activity as well as participation in daily living activities

Blokovi perifernih živaca u bolesnika s prijelomom kuka

Hip fractures represent a major public health issue with increasing incidence as a population ages. The aim of this review is to describe peripheral nerve block techniques (the fascia iliaca compartment block and the pericapsular nerve group block) as pain management for hip fractures in emergency medicine, and to emphasize their benefits. Hip fractures are extremely painful injuries. The pain itself is unpleasant for patients and if left untreated it can lead to multiple complications during preoperative, operative and postoperative patient management. Pain management for elderly hip fracture patients is often challenging. Non-steroidal anti-inflammatory drugs are not recommended due to their side effects, the increased risk of gastrointestinal bleeding, renal function impairment and platelet aggregation inhibition. Paracetamol alone is often insufficient, and opioids have many potentially harmful side effects, such as delirium development. Peripheral nerve blocks for hip fractures are safe and effective, also in emergency medicine settings. The benefits for patients are greater pain relief, especially during movement, less opioid requirements and decreased incidence of delirium. Regional analgesia should be routinely used in hip fracture pain management.Prijelom kuka predstavlja značajan javno zdravstveni problem čija će incidencija rasti sa starenjem populacije. Cilj ovog preglednog članka je opisati blokove perifernih živaca u liječenju boli kod bolesnika s prijelomom kuka, (bloka ilijakalne fascije i bloka perikapsularnih živaca), te naglasiti prednosti njihove primjene. Prijelom kuka je izrazito bolna ozljeda. Bol sama po sebi je neugodna za bolesnika, a ukoliko je neodgovarajuće liječena može dovesti do višestrukih komplikacija tijekom prijeoperacijskog, operacijskog i poslijeoperacijskog zbrinjavanja bolesnika. Unatoč postojanju brojnih analgetika, liječenje boli u starijih bolesnika s prijelomom kuka često je zahtjevno. Nesteroidni protuupalni lijekovi se ne preporučuju radi svojih neželjenih učinaka, paracetamol je često nedovoljan, a opioidi također mogu imati brojne neželjene učinke, uključujući razvoj akutnog smetenog stanja. Primjena blokova perifernih živaca je sigurna i učinkovita, također u uvjetima hitne medicine. Koristi za bolesnike su bolje ublažavanje boli, osobito prilikom pomicanja, smanjena potreba za primjenom opioida i smanjena incidencija akutnog smetenog stanja. Primjena blokova perifenih živaca u liječenju boli kod bolesnika s prijelomom kuka trebala bi postati svakodnevnica u kliničkoj praksi

Analysis of interrelations between wheat protein fractions composition and its technological quality by combined multivariate and univariate statistics

Data on protein fractions' proportion, obtained with RP-HPLC and technological quality parameters for 29 wheat cultivars grown in Serbia and Croatia, were used for studying of interrelations among wheat protein fractions with different solubility and molecular weight properties by multivariate (PCA) analysis. Obtained trends were used as the base for investigations related to differentiation of technological quality among wheat cultivars with different combination of protein fractions' compositions using univariate statistics (ANOVA followed by Duncan's test) in order to draw out information about interrelations between protein fractions proportion in wheat cultivars and their technological quality. Analysis based on the first four PCA factors (89.04% of variability) pointed out interdependencies between: 1) high content of albumins and globulins, low gliadins content and gliadins/glutenins ratio, high omega-gliadins, LMW glutenins and low alpha-gliadins share in total protein with low water absorption, high energy and high resistance to extensibility ratio, 2) high albumin and globulin content and high proportion of omega-gliadins in total protein and low extensigraph extensibility, 3) high share of high molecular weight glutenins (HMW-GS) in total proteins, high extensigraph resistance/extensibility ratio and 4) high gamma-gliadins share in total protein and low extensigraph resistance/extensibility ratio