Subjektivni doživljaj siromaštva meðu mladima u ruralnim područjima Srbije

Poverty is a complex phenomenon faced by youth too. The purpose of this research is to determine the presence of the problem of poverty among youth in rural areas of Serbia. Survey has been conducted in five villages of Paraćin municipality. Exactly 98 young men and women took part in the survey, ages between 20 and 34, and they were asked to answer questions regarding poverty, to estimate their own poverty, and their own social exclusion. Desk research was supplemented with empirical research in the mentioned areas. Results of research conducted in the field are represented in the second part of this paper. In order to perceive the position and poverty of youth, their satisfaction with their living environment, and social exclusion of youth, we relied on the questionnaire that enables expressing subjective welfare. Data obtained through research indicate that one in ten subjects of the survey is poor. The surveyed subjects belonging to the oldest age group (30-34 years of age) and residents of settlements in the vicinity of municipality’s center are in a more unfavorable position. Survey results show that the young in rural areas have been facing the problem of their own poverty to a great extend during their lives. Social exclusion was recorded with 42% of the subjects, who claimed that they had felt isolated from the community at some point in the past two years, due to lack of money

Calculation of the Archard's wear coefficient of the polymer-based composite sliding bearings

Prediction and calculation of wear of the mechanical components in contact is one of the most important tasks in modern engineering. Due to time consumptive experiments and quite expensive test rig, it became even more challenging to evaluate wear by means of the computer simulation instead of the real experiments. With rapid improvement of the computer resources, this task became more realistic, and the results are more concurrent to those obtained by experiments. Since the most of the solvers evaluate wear by means of the Archard's equation, to perform the simulation it is mandatory to determine Archard's coefficient K. This paper provides necessary steps, experimental investigations and measurements in order to calculate Archard's coefficient K, as an input value for the simulation of wear of the polymer-based composite sleeve bearings

Heat transfer and lubrication of turboshaft motor-reducer

Turboshaft engines, as the rule, contains gear transmission unit - reducer and belong to the group of drive systems with the name motor-reducer. These are the compact and autonomous assemblies for various applications. In the case of turboshaft engine in combination with high speed reducer, arise the set of phenomenon which has to be solved. Majority of them are in relation to reducer protection of overheating and of gears and bearings failures. The article contains analysis of heat sources, heat transfer through design structure and heat taking out in order to maintain acceptable temperature level of reducer lubricant. Theoretical discussions are supported with various experimental results and testing procedures, including analytic calculations. The set of design solutions for reducer protection when reducer located in the area of hot gas flow, is the main content. The case study is innovative design of turboshaft motor-reducer with free turbine which provides flexible operation and compact design structure

Wear simulation of the polymer based composite sliding bearings by means of ansys

Polymer based composite sliding bearings are increasingly applied in many industries, due to their economic (usually low cost of production) and technical (good tribological properties) benefits. In order to predict their life cycle, it is necessary to perform numerous experiments and evaluate their wear rate. This is generally quite expensive and time consuming. By applying only one series of the experiments and determining Archard’s wear coefficient, and embedding it into the code of the Ansys software, it is possible to simulate the wear, and thus save the time and the financial resources. This paper explains the procedure of the wear simulation in case of known Archard’s coefficient, for sliding bearings made of PTFE polyamide composite material in contact with shaft of steel. The output of the simulation is the contact pressure in relation of time and the amount of worn volume for 3 revolutions of the shaft

Wear simulation of the polymer based composite sliding bearings by means of ansys

Polymer based composite sliding bearings are increasingly applied in many industries, due to their economic (usually low cost of production) and technical (good tribological properties) benefits. In order to predict their life cycle, it is necessary to perform numerous experiments and evaluate their wear rate. This is generally quite expensive and time consuming. By applying only one series of the experiments and determining Archard’s wear coefficient, and embedding it into the code of the Ansys software, it is possible to simulate the wear, and thus save the time and the financial resources. This paper explains the procedure of the wear simulation in case of known Archard’s coefficient, for sliding bearings made of PTFE polyamide composite material in contact with shaft of steel. The output of the simulation is the contact pressure in relation of time and the amount of worn volume for 3 revolutions of the shaft

Forenzička nauka i kriminalistika

The aim of this paper is to point to the innovations in higher police education in Serbia arisen from introduction of forensic science in study plans and programmes. An attempt was made to distinct and more clearly determine the content of basic terms important for the development of police education. It was also pointed to the significance the organization of criminalistic terminology has for successful scientific-research process in police education and for successful communication between the professionals in all the segments of criminalistic work, that is, in the broadest sense, in the field of internal affairs and criminal justice.Cilj ovog rada je da se ukaže na novine u visokom policijskom obrazovanju u Srbiji koje su nastale uvođenjem forenzičke nauke u nastavne planove i programe. U radu je napravljen pokušaj da se razgraniči i jasnije odredi sadržaj osnovnih pojmova koji su veoma bitni za razvoj policijskog obrazovanja. Takođe, naglašen je značaj uređenja kriminalističke terminologije za uspešan naučno-obrazovni proces u policijskom školstvu i za uspešnu komunikaciju stručnjaka u svim segmentima rada u vezi sa kriminalističkom delatnošću, a to su, u najširem smislu, oblast unutrašnjih poslova i krivičnog pravosuđa

Analiza načina izvršenja krivičnog dela silovanja

By using nonmetric multidimensional scaling 1126 solved rape cases (article 103 Criminal Law of Republic of Serbia) has been analyzed. The data were taken from Department of Informatics of Ministry of Interior affairs of republic of Serbia and were collected from Serbia and Vojvodina from 1991. to 2001. Elementary crime scene characteristics have been analyzed and those were location type, weapons, method of approach, method of attack, method of arriving and opportunistic elements. Set of nominal variables was transformed to binary form and analyzed by "alscal" technique. In accordance with earlier researches it has been chosen two-dimensional solution. Stress value 0.157 was acceptable. Examination of visual plot made it possible to divide rapist in two groups, based on crime scene characteristics. First group consisted of rapists who use indoor locations such as flat, public or working place, who use weapons or physical force, sex invitation or blitz approach. They tend to exploit victim's weakness or helplessness, they use vehicles in arriving to the crime scene and they choose certain locations or time as opportunistic elements. Second groups consisted of rapist who uses threat in outdoor locations, confident approach, they arriving bye foot and exploit some victim's features such as ignorance or thrust. In the end results were brought in connection with earlier theoretical findings.Primenom nemetričkog multidimenzionalnog skaliranja analizirano je 1126 rasvetljenih krivičnih dela silovanja, član 103 Krivičnog zakona Republike Srbije. Podaci su dobijeni iz Uprave za informatiku Ministarstva unutrašnjih poslova i odnose se na teritoriju Srbije i Vojvodine u periodu od 1991. do 2001. godine. Analizirane su elementarne informacije koje se odnose na način izvršenja krivičnog dela, a to su prostor, sredstvo, način izvršenja, način prilaska žrtvi, način dolaska i korišćene okolnosti. Nepotpuni slučajevi bili su izbačeni iz analize. Skup nominalnih varijabli pretvoren u binarni oblik obrađen je postupkom "alskal", na ordinalnom nivou merenja. U skladu sa ranijim istraživanjima, izabrano je rešenje sa dve dimenzije. Vrednost stresa iznosila je 0.157 što je ocenjeno kao prihvatljivo. Pregledom koordinatnog sistema koga su činile izolovane dimenzije bilo je moguće podeliti radnje izvršioca na dve grupe. Jednu su činila silovanja izvršena u zatvorenom prostoru poput stana, javnog mesta ili radnog mesta, upotreba oružja ili fizičke sile, poziv na neku aktivnost ili iznenadan prilazak, korišćenje nemoći žrtve ili stanja žrtve, izbor pogodnog vremena ili lokacije i korišćenje prevoznog sredstva za dolazak. Drugu grupu odlikovao je izbor pustog mesta na otvorenom prostoru, prilazak pomoću trika, korišćenje pretnje, izbor žrtve sa određenim svojstvima poput naivnosti, poverenja starosti itd. i dolazak pešice. Na kraju je pokušano da se rezultati dovedu u vezu sa nekim od dosadašnjih teorijskih nalaza o ponašanju i motivaciji silovatelja

Heat transfer and lubrication of turboshaft motor-reducer

Turboshaft engines, as the rule, contains gear transmission unit - reducer and belong to the group of drive systems with the name motor-reducer. These are the compact and autonomous assemblies for various applications. In the case of turboshaft engine in combination with high speed reducer, arise the set of phenomenon which has to be solved. Majority of them are in relation to reducer protection of overheating and of gears and bearings failures. The article contains analysis of heat sources, heat transfer through design structure and heat taking out in order to maintain acceptable temperature level of reducer lubricant. Theoretical discussions are supported with various experimental results and testing procedures, including analytic calculations. The set of design solutions for reducer protection when reducer located in the area of hot gas flow, is the main content. The case study is innovative design of turboshaft motor-reducer with free turbine which provides flexible operation and compact design structure

Dynamic stiffness method in the vibration analysis of circular cylindrical shell

In this paper the dynamic stiffness method is used for free vibration analysis of a circular cylindrical shell. The dynamic stiffness matrix is formulated on the base of the exact solution for free vibration of a circular cylindrical shell according to the Flügge thin shell theory. The matrix is frequency dependent and, besides the stiffness, includes inertia and damping effects. The derived dynamic stiffness matrix is implemented in the code developed in a Matlab program for computing natural frequencies and mode shapes of a circular cylindrical shell. Several numerical examples are carried out. The obtained results are validated against the results obtained by using the commercial finite element program Abaqus as well as the available analytical solutions from the literature.U ovom radu korišćena je metoda dinamičke krutosti za analizu slobodnih vibracija kružne cilindrične ljuske. Dinamička matrica krutosti formulisana je na osnovu tačnog rešenja sistema diferencijalnih jednačina problema slobodnih vibracija po Flügge-ovoj teoriji ljuski. To je frekventno zavisna matrica koja u sebi, pored krutosti, sadrži uticaj inercije i prigušenja. Izvedena dinamička matica krutosti implementirana je u za tu svrhu napisani Matlab program za određivanje sopstvenih frekvencija i oblika oscilovanja kružne cilindrične ljuske. Urađen je niz primera. Rezultati dobijeni primenom dinamičke matrice krutosti upoređeni su s rezultatima dobijenim pomoću komercijalnog programa zasnovanog na metodi konačnih elemenata Abaqus, kao i sa dostupnim analitičkim rezultatima iz literature