Uticaj strukture čestica na nasipnu masu elektrolitički dobijenog bakarnog praha

The quantitative microstructural analysis and the sieve analysis of copper powder as well as the scanning electron microscopy analysis of the copper powders particles were performed. It was found that the structure of the copper powder particles determines the apparent density of copper powder. The powder particles from the same fractions of different powders occupy approximately the same volume, but the structure of metallic copper is very different. This causes the difference in apparent densities of copper powder obtained under different conditions. The more dendritic is the structure of powder particles the smaller is the apparent density of copper powder.Izvršena je kvalitativna mikrostrukturna i granulometrijska analiza bakarnih prahova kao i analiza morfologije i strukture čestica praha pomoću skenirajuće elektronske mikroskopije (SEM). Ustanovljeno je da struktura čestica praha određuje nasipnu masu bakarnog praha. Čestice iste frakcije različitih prahova zauzimaju otprilike istu zapreminu, ali je struktura metalnog bakra različita. Ovo uzrokuje razlike u nasipnoj masi bakarnog praha dobijenog pod različitim uslovima. Što je struktura čestica više dendritična to je manja nasipna masa bakarnog praha

Structural characteristics of electrodeposited copper coatings

Uzorci bakra su podvrgnuti mehaničkom i elektrohemijskom glačanju u odgovarajućim elektrolitima za elektrohemijsko glačanje. Na tako prethodno pripremljene površine supstrata izvršeno je taloţenje prevlaka bakra iz dva kupatila i to iz osnovnog elektrolita (OR) sastava: 240 g/dm3 CuSO4 ∙ 5 H2O + 60 g/dm3 H2SO4 i kupatila sa dodacima za sjaj (OR +DS). Pomoću STM i AFM tehnika precizno su prikazane strukturne osobine koje odreĎuju da li je metalna površina ogledalski sjajna ili ne, odnosno da li dobijena topografija površine manje ili više hrapava. UtvrĎeno je znatno povećanje hrapavosti uzoraka na koje je taloţena prevlaka bakra iz osnovnog sulfatnog kupatila (OR) u odnosu na mehanički i mehanički i elektrohemijske pripremane uzorke. TakoĎe, pri taloţenju prevlaka iz kupatila sa dodacima za sjaj (OR +DS), došlo je do smanjenja hrapavosti površine.The samples of rolled copper were mechanically and electrochemically polished in suitable electrolytes for electrochemical polishing. These substrate surfaces that had been prepared in advance, served as the basis for depositing of copper layers from two baths, namely, from the basic electrolyte(OR) with the following composition: 240 g/dm3 CuSO4 ∙ 5 H2O + 60 g/dm3 H2SO4i as well as from the bath which contained brightening addition agents(OR +DS). STM and AFM techniques show in great detail the structural properties which determine whether the metal surfaceis are as bright as a mirrior or not, that is, whether the obtained topography of the surface is more or less rough. It was determined that a considerable increase of roughness occurred in the samples where copper layers were deposited from the basic sulfate bath (OR) when compared with mechanical, and mechanical-electrochemical samples. In addition, depositing of the samples from the bath with brightening addition agents (OR +DS) resulted in the decrease of surface roughness

The effect of sociodemographic characteristics on the self-evaluation of health among the population in Serbia

This paper analyses the impacts of various demographic and socioeconomic characteristics on the way Serbian people assess their own health. Marital status, education level, and occupation were analysed using the threeway ANOVA statistical method. The results of the statistical analysis show that each of the selected features significantly affects the subjective experience of health conditions. Regarding marital status, unmarried people assessed their health status most favourably. In terms of education, a better perception of health was observed in people with higher levels of education. And considering gender, only marital status had an impact on the self-assessment of health in both sexes. For men, education had an impact, whereas for women, it was the type of occupation. The specificity in perception of one’s own health in the elderly population of Serbia (above 60 years old) is reflected in the fact that occupation was the only factor that influenced the subjective experience of health status. © 2022 Demographic Research Centre. All rights reserved

Electrochemical deposition and characterization of Ni-Mo alloy powders

Electrodeposition of Ni-Mo alloy powders from ammonium sulfate and ammonium chloride containing electrolytes of different Ni/Mo ions concentration ratios was investigated by polarization measurements. The morphology, chemical composition and phase composition of electrodeposited Ni-Mo alloy powders were investigated using DSC, TGA, SEM, EDS and XRD analysis. EDS results showed that powder composition depends on Ni/Mo ions concentration ratio, as well as on the position where the EDS analysis was performed. As-deposited alloy powders were nanocrystalline showing no XRD peaks with undefined morphology (SEM). After recrystallization for 2 h in N2 atmosphere at 600°C the presence of NiMoO4 phase was identified in the powder electrodeposited from chloride electrolyte at the Ni/Mo ions concentration ratio 1/3, with well defined crystalline powder particles

Elektrohemijsko taloženje i koroziona stabilnost prevlaka Zn-Mn legura

The influence of the type of the deposition solution on the current efficiency during electrodeposition of Zn-Mn alloys was examined. The Zn-Mn alloys were deposited on steel from chloride, sulphate and pyrophosphate plating baths at different current densities. The influence of deposition current density on the appearance of alloy coatings, as well as their corrosion stability, was examined. It was shown that Zn-Mn alloys with the best corrosion properties, among all investigated in this work, were obtained from chloride plating bath at 2 A dm-2. .Izučavan je uticaj vrste rastvora za taloženje na iskorišćenje struje prilikom elektrohemijskog taloženja Zn-Mn legura. Legure su taložene na čeliku iz hloridnog, sulfatnog i pirofosfatnog rastvora različitim gustinama struje. Ispitivan je uticaj gustine struje taloženja na izgled prevlaka legura, kao i njihovu korozionu stabilnost. Pokazano je da najveću korozionu stabilnost imaju legure dobijene taloženjem iz hloridnog rastvora gustinom struje od 2 A dm-2

Searching for an interstellar medium association for HESS J1534-571

The Galactic supernova remnant HESSJ1534−571 (also known as G323.7 − 1.0) has a shell-like morphology in TeV gamma-ray emission and is a key object in the study of cosmic ray origin. Little is known about its distance and local environment. We examine Mopra 12CO/13CO(1–0) data, Australian Telescope Compact Array HI⁠, and Parkes HI data towards HESSJ1534−571⁠. We trace molecular clouds in at least five velocity ranges, including clumpy interstellar medium structures near a dip in HI emission at a kinematic velocity consistent with the Scutum–Crux arm at ∼3.5 kpc. This feature may be a cavity blown-out by the progenitor star, a scenario that suggests HESSJ1534−571 resulted from a core-collapse event. By employing parametrizations fitted to a sample of supernova remnants of known distance, we find that the radio continuum brightness of HESSJ1534−571 is consistent with the ∼3.5 kpc kinematic distance of the Scutum–Crux arm HI dip. Modelling of the supernova evolution suggests a ∼8–24 kyr age for HESSJ1534−571 at this distance.Nigel I. Maxted, C. Braiding, G. F. Wong, G. P. Rowell ... Gavin P. Rowell ... Fabien Voisin ... et al