Copper production in Majdanpek in sixties and seventies of the 16th century

In this paper the practice of mine Majdanpek during sixties and seventies of the XVI century has been investigated with an accent on copper production. The attention has been also given to various subjects from considering copper treatment and use to forbidden activities connected to copper illegal production and trade with Persia

Use of engineering tools in modelling first bite-case study with grilled pork meat

This study provides an engineering approach in modelling the first bite. Based on the mechanical properties of grilled pork meat obtained by applying compression and Warner Bratzler tests and using the Finite element method, a 3D model of cubic pieces has been created. It was then used for simulating the first bite of pork meat grilled at two temperatures and three positions of the jaws. Stress distribution during impact of upper and lower jaw shows growth of internal stress in the direction of jaw movement, leading to crack development and breaking of meat

Use of engineering tools in modelling first bite-case study with grilled pork meat

This study provides an engineering approach in modelling the first bite. Based on the mechanical properties of grilled pork meat obtained by applying compression and Warner Bratzler tests and using the Finite element method, a 3D model of cubic pieces has been created. It was then used for simulating the first bite of pork meat grilled at two temperatures and three positions of the jaws. Stress distribution during impact of upper and lower jaw shows growth of internal stress in the direction of jaw movement, leading to crack development and breaking of meat

A revised modified Bentall's procedure using aorto-prosthetic hemostatic suture

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Istraživanje mehanizma i kinetika procesa oksidacije halkopiritnog koncentrata

The oxidation process of chalcopyrite concentrate ″Rudnik″ (Serbia) was investigated by DTA-TG measurements under air conditions in the temperature range of 298 – 1173 K, as well as by XRD analysis of the oxidation products at 723, 873 and 1173 K. Based on the results obtained, the mechanism of chalcopyrite concentrate oxidation process was given, contributing to the understanding of the successive chemical reactions accompanying the formation of intermediate products. The kinetic study of the investigated process was done according to the methods of Kissinger and Ozawa, which enabled determination of the activation energy values of the chemical reactions proceeding during the chacopyrite concentrate oxidation.Proces oksidacije halkopiritnog koncentrata ″Rudnik″ (Srbija) ispitivan je DTA-TG mjerenjima u atmosferi zraka i temperaturnom intervalu 298–1173 K, kao i XRD analizama produkata oksidacije na 723, 873 i 1173 K. Na temelju dobivenih rezultata predložen je mehanizam oksidacije halkopiritnog koncentrata uključujući i kemijske reakcije koje prate stvaranje odgovarajućih međuproizvoda. Za ispitivanje kinetike procesa rabljene su metode Kissinger i Ozawa, kojima su određene vrijednosti energija aktivacije kemijskih reakcija tokom oksidacije halkopiritnog koncentrata

Iridium anomaly in the cretaceous-paleogene boundary at Højerup (Stevns Klint, Denmark) and Woodside Creek (New Zealand): The question of an enormous proportion of extraterrestrial component

The Cretaceous-Paleogene boundary clays at Højerup and Woodside Creek show anomalous enrichments of iridium compared with the marine sedimentary rocks. For the average iridium content of 465 ppb in CI chondrite the estimate of the carbonaceous chondritic proportions in the decarbonated iridium-rich boundary layers, based on the integrated iridium fluencies, is about 26% at Højerup and 65% at Woodside Creek. These proportions are most likely too high due to a significant Ir influx from the nearby marine or continental site to these sections

Processing, properties and application of bismuth ferrite-based multiferroic materials.

Bizmut-ferit (BiFeO3) ispoljava jedinstvena svojstva koja pre svega doprinose teorijskom shvatanju električnih i magnetnih uređenja i njihove interakcije u kristalnim oksidnim materijalima, ali bi uz prevazilažanje trenutno postojećih prepreka materijala na bazi bizmut-ferita mogli naći primenu u mnogim oblastima. Postoji samo nekoliko jednofaznih materijala kojima se može pripisati više feroičnih svojstava (feroelektrična, feroelastična, (anti)feromagnetna) na temperaturama višim od 50 K. Zbog toga ne čudi da je baš bizmut-ferit, koji i na temperaturama iznad sobne može ispoljiti feroelektričnost, feroelastičnost, pa čak i slab feromagnetizam (iako je po magnetnoj strukturi antiferomagnetan), predmet istraživanja brojnih naučnih radova iako i dalje ne postoje uređaji koji u sastavu sadrže bizmut-ferit...Bismuth ferrite (BiFeO3) theoretically possesses very peculiar properties, and understanding them may be the key of understanding the nature of interaction between electrical and magnetic orderings in crystalline oxides. If problems in exhibiting those properties were overcome, bismuth ferrite-based materials might be widely applicable. Few single phase materials exhibit two or three of the ferroic properties (ferroelectric, ferroelastic, (anti)ferromagnetic) at temperatures above 50 K. Being ferroelectric, ferroelastic and even weakly ferromagnetic (although possessing antiferromagnetic structure of magnetic spins) at temperatures well above the room temperature, bismuth ferrite is the subject of hundreds of scientific studies with good reason, although its application is still far from being realized..

The analysis of particles emission during the process of grinding of steel EN 90MNV8

Metal grinding is a one of the manufacturing technologies that is greatly connected to particles emission. Particles generated during the grinding process are dangerous in terms of its potential penetration deeply into the lungs of an operator. The level of risk for human respiratory system is related to nature, shape and size of the particles, and for this reason it is important to have a quality characterization of emitted particles. This paper focuses on particles characterization on the bases of image analysis from scanning electron microscopy (SEM). The research was conducted during the process of grinding of steel EN 90MnV8, using personal sampler. Results of image analysis, consisted of Feret’s diameter and circularity, showed quite a wide range of sizes and significant deviation of particles from regular shape