Effect of spring-back in v-tool bending of high-strength steel sheet metal plates

This paper deals with the effects of technological parameters used in the V-die bending process, on the obtained product properties and dimensions. By variation of the tool geometry, several cases of steel sheet bending process are observed through the FEM simulations. Also by variation of different mechanical material properties, effects on product geometry are observed. Since the automobile manufacturers mostly use the high strength steel sheet metal plates, there is a need for the successful tool construction and optimization in order to produce quality products

Utjecaj materijala i geometrije radnog komada kod savijanja laserom

Seit den siebziger Jahre ist durch die Einführung des Laserstrahls in die Fertigungstechnik eine ganze Reihe neuer Verfahren entstanden. Einige dieser Verfahren sind mittlerweile in die technische Anwendung übergangen wie zu Beispiel Schneiden, Schweißen, Drehen, Fräsen, Bohren und Umformen. Gemeinsames Merkmal der Lasergestützten Formgebungsverfahren ist die digitale Speicherung der Werkstückgeometrie in einem NC-Programm anstelle der analogen Speicherung im Werkzeug und sukzessive Abarbeitung dieses Programm, die zusätzlich Steuermöglichkeiten während des Prozessablaufs ermöglicht. Weiterhin ergibt die Vorgehensweise eine sehr hohe Flexibilität hinsichtlich der Werkstückgeometrie, die im Bereich des Rapid Prototyping genutzt werden. In dieser Arbeit wird Werkstoff - Geometriewerkstückbeeinflussung auf den Laserstrahlbiegen analysiert. Einfluss hat Blechdicke, längen der Biegekante und Biegeschenkel.Od kada je sedamdesetih godina uveden laser u tehnologiju izrade nastali su mnogi novi postupci. Neki od tih postupaka našli su tehničku primjenu u tehnologiji izrade kao na primjer rezanje, zavarivanje, tokarenje, glodanje, bušenje i oblikovanje metala deformiranjem. Karakteristika je postupka izrade potpomognuta laserom digitalno spremanje geometrije radnog dijela u NC - program, provođenje analognog spremanja podataka u (stroj) alat i sukcesivna obrada ovog programa, koji osigurava dodatno mogućnost upravljanja za vrijeme odvijanja procesa. Nadalje, postiže se fleksibilnost s obzirom na geometriju radnog komada, koja se primjenjuje u području brze izrade prototipova. U ovom se radu analizira utjecaj materijala i geometrije radnog komada na savijanja laserom. Utjecaj ima: debljina lima, duljina ruba savijanja i duljina kraka savijanja

Dijagnostika gravidnosti koza

Dijagnostika gravidnosti bitan je segment veterinarske djelatnosti u upravljanju i kontroli rasplođivanja koza, posebice prilikom držanja u intenzivnom uzgoju. Premda vlasnik životinje može posumnjati na gravidnost, neizbježna je uloga veterinara da kliničkom pretragom i metodama poput ultrazvuka ili laboratorijskih testova utvrdi je li životinja gravidna ili nije i shodno tomu poduzme sve potrebne mjere oko reproduktivnog statusa životinje. Specifičnost spolnog ciklusa koza i sezonska poliestričnost dodatne su okolnosti i stvaraju potrebu za što ranijom dijagnostikom gravidnosti. Zadnjih četrdesetak godina dijagnostičke metode su usavršene tako da je moguće relativno brzo i lako dobiti nalaze dijagnostike, i to ne samo gravidnosti nego i podatke o starosti plodova, njihovoj brojnosti i vitalnosti

Use of ultrasonography to detect ovarian response in goats submitted to multiple ovulation and embryo transfer program

The aim of this research was to establish the importance and accuracy of ultrasonic examination of goats in order to estimate the superovulatory response. For this reason, 28 donor goats were systematically examined by real time ultrasonography to count the preovulatory follicles at observed oestrus onset and to confirm respective ovulation(s) 48 h later. The accuracy of ultrasound exams was analysed comparing the number of preovulatory follicles with number of corpora lutea (CL′s) counted during embryo collection. The total relative undervalue of ultrasound prediction of multiple ovulation was found to be 19.4%. In all ovaries examined, the total number of preovulatory follicles minus number of unovulated follicles was lower than the number of CL′s. The relationship between the predicted ovulation rate and number of CL's was positive and significant (CL 3.98 + 0.75 follicle; r2 0.93), with significantly higher intercept (1.45) for the right ovary. Also, the accuracy of ultrasound to establish the ovulating and non-ovulating goats was 100.0%. However, determination of the exact number of multiple ovulations on ovaries was 45.0%. In conclusion, the ultrasonography of donor goats is an useful tool to monitor follicular dynamics and success of superovulation procedures. Counting the number of follicles >4 mm in diameter at the oestrus onset and confirming the ovulation is a good method for selection of responding goats prior to flushing of uterus

Flock-reprod: hormone-free non-seasonal or seasonal goat reproduction for a sustainable European goat-milk market

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