Measurement of 60CO gamma radiation induced attenuation in multimode step-index POF at 530 nm

As optical fibres are used ever more extensively in space applications, nuclear industry, medicine and high-energy physics experiments, it has become essential to investigate the influence of ionizing radiation on their characteristics. In this work, the radiation-induced attenuation at 530 nm is investigated experimentally in step-index multimode polymethyl-methacrylate plastic optical fibres exposed to low dose-rate gamma radiation. Cumulative doses ranged from 50 Gy to 500 Gy. The radiation induced attenuation has been empirically found to obey the power law RIA= aDb, where D is the total radiation dose and a and b are the constants determined by fitting

Stark Broadening in Compact Stars: Xe VI Lines

International audienceWe will consider Stark broadening of non hydrogenic spectral lines in the impact approximation in compact stars: pre-white dwarf and white dwarf atmospheres. In order to show an example, Stark broadening parameters have been calculated, using the impact semiclassical perturbation approach for four Xe VI spectral lines. Obtained results have been used to demonstrate the influence of Stark broadening in DA and DB white dwarf atmospheres

Nursery Production of Black Walnut (Juglans nigra L.) Seedlings

U radu se analiziraju neki od elemenata kakvoće sjemena crnoga oraha i ispituju njegova svojstva. U proljeće 2004. godine obavljena je sjetva stratificiranog sjemena na dva načina: na gredice i u dva tipa zbirnih kontejnera (Bosnaplast 18 i kontejner dimenzija 35,5x27,0 (16) sa 24 rupe za sadnju). Najveća rasadnička klijavost dobivena je kod sjemena posijanog u kontejner Bosnaplast 18 (55,00 %), slijedi rasadnička klijavost sjemena posijanog na gredice (42,99 %) i u drugi tip kontejnera (20,83 %). Prosječno najveće visine na kraju prve vegetacije (1+0) imale su sadnice uzgajane na gredici (315 mm). Visine sadnica u kontejneru Bosnaplast 18 bile su u prosjeku niže za 61 mm a u drugom tipu kontejnera za 67 mm u odnosu na sadnice uzgajane na gredici. U jesen 2004. godine obavljena je sjetva nestratificiranog sjemena na dva načina, s obzirom na čišćenje mesnatog usplođa ploda. Dio sjemena posijan je s usplođem, a dio bez usplođa. Rasadnička klijavost očišćenog sjemena iznosila je 91,67 % a sjemena posijanog sa usplođem 73,00 %. Najveću visinu na kraju prve vegetacije (1+0) imale su nepodrezane sadnice uzgojene iz sjemena s očišćenim usplođem (524 mm). Nepodrezane sadnice uzgojene iz sjemena bez čišćenja usplođa bile su prosječno niže od sadnica uzgojenih s očišćenim usplođem za 185 mm. Podrezane sadnice, u jednom i drugom slučaju, bile su niže od nepodrezanih.The paper analyzes some of the elements of Black walnut seed quality and examines its characteristics. In spring 2004 stratified seed was sown in two ways: on nursery beds and in two types of multiple containers (Bosnaplast 18 and a 35,5x27,0 (16) container with 24 holes). The seed sown in the Bosnaplast 18 container showed the largest germination percentage (55,00 %), followed by nursery germination of seed sown on beds (42,99 %) and in the other type of container (20,83 %). At the end of the current growing season (1+0) the bed-grown seedlings had the largest height (315 mm). The seedlings grown in the Bosnaplast 18 container 18 were on average lower by 61 mm and those from the other container by 67 mm with respect to the bed-grown seedlings. In autumn 2004 non-stratified seed was sown in two ways: with and without cleaning husks. Part of the seed was sown with and part without husks. The nursery germination of the cleaned seed amounted to 91,67 % while the germination of the seeds sown with husks reached 73,00 %. The non-undercut seedlings raised from the cleaned seeds had the largest height (524 mm) at the end of the current growing season (1+0). The non-undercut seedlings raised from uncleaned seeds were on average lower by 185 mm compared to the seedlings raised from cleaned seeds. In both cases the undercut seedlings were lower than the non-undercut ones

Uticaj stimulativnih mera na motivaciju pripadnika Vojske Srbije

nem

Thermodynamic Optimization Of Cascade Heat Pump

In today’s modern world, development of industry and technology has led to the increase in energy demand. Hence, more fossil fuels are burnt in order to cover this demand. Due to the multiple disadvantages, as well as the neg-ative impact that burning of fossil fuels has on the environment, heat pumps are gaining more importance when provid-ing energy for heating. This paper is aimed at conducting thermodynamic optimization of cascade heat pump in terms of different working fluid combinations and calculating maximum COP. In order to perform thermodynamic analysis, a software program that uses database of working fluids, was developed. The intermediate temperature within cascade heat exchanger represents a crucial parameter when analyzing and designing cascade heat pumps. Thus, when per-forming thermodynamic analysis, the intermediate temperature was varied in the range from 0⁰С to 25⁰С and the opti-mal temperature that provides maximum COP was defined. The analysis was performed on an air-to-water heat pump, that could be used for heating different types of buildings in places in Serbia where the outdoor design temperature is -20⁰С. The cascade heat pump would be used alongside radiator heating system operating at temperatures 70⁰С/50⁰С. Due to the high temperature difference between heat source and heat sink, cascade heat pumps have advantages over single stage or multi stage heat pumps. The optimization was performed on an air-to-water cascade heat pump where the evaporation and condensation temperatures were -25⁰С and 75⁰С, respectively. Following the conducted optimization, the analysis of the impact that isentropic efficiency of compressor has on COP was examined

Model za podršku odlučivanju pri selekciji pripadnika vojske srbije za upućivanje na karijerna usavršavanja

nem

Krađe motornih vozila kao savremeni vid organizovanog kriminala u domaćoj kriminalističkoj praksi

The first part of the paper outlines the normative and legal framework within which criminal law provides protection of motor vehicles and lists the problems encountered by the judiciary in the practical implementation of legal provisions. The central part of the paper focuses on the modus operandi of organized criminal groups engaged in the perpetration of such criminal acts, particularly in the organization and deployment of various electronic tools used to overcome electronic protection of modern vehicle makes. Finally, the authors emphasize the fact that investigative activities aimed at tracking down organized criminal groups and identifying the roles of their members call for an approach that differs from that used for detecting other criminal acts and point out to the main guidelines for police activities aimed at dealing with such cases.U prvom delu rada autori ukazuju na normativno-pravni okvir kojim se obezbeđuje krivično-pravna zaštita motornih vozila i na probleme koji se pojavljuju u njegovoj praktičnoj primeni od strane policije i pravosuđa. Centralni deo rada tretira modus operandi organizovanih kriminalnih grupa vezan za ovu vrstu krivičnih dela, a u prvom redu organizaciju kriminalne aktivnosti i primenu različitih elektronskih alata u cilju savlađivanja elektronske zaštite prisutne na novijim tipovima vozila. Na kraju, autori ukazuju na činjenicu da kriminalistička delatnost razotkrivanja organizovanih kriminalnih grupa oformljenih za vršenje krivičnih dela krađa vozila, njihove strukture i uloge pojedinih članova, zahteva drugačiji pristup u odnosu na druga krivična dela, te ukazuju na osnovne pravce policijske delatnosti koja se preduzima u tom cilju