Procena koeficijenta heritabiliteta za broj živorođene prasadi u prva tri prašenja krmača švedskog landrasa

The main objective of this study was to evaluate phenotypic and genetic variation of the number of piglets born alive (NBA) Swedish Landrace sows (SL) in three consecutive parities under the influence of sires, year and season of mating. The study included: 618 litters in the first, 470 in the second and 403 litter in the third farrowing. Testing the homogeneity of variance was performed with Levene's test. The data were analyzed using analysis of variance (Statistica Ver. 6.0., 2003). Heritability coefficients were evaluated by intra-class correlation. Swedish Landrace sires have influenced on the variability of the NBA's daughter in the first and second farrowing (p (lt) 0.05), but not in the third farrowing. Year and season of mating was not influenced on the variability of the NBA (p>0.05). The estimated heritability coefficients for the NBA were the highest in the second (0.123), then the first (0.092) and lowest in the third farrowing (0.030).Osnovni cilj rada bio je da se oceni fenotipska i genetska varijabilnost broja živorođene prasadi (NBA) krmača švedskog landrasa (SL) u tri uzastopna prašenja pod uticajem očeva, godine i sezone pripusta. Istraživanjem je bilo obuhvaćeno: 618 legala u prvom, 470 u drugom i 403 legla u trećem prašenju. Testiranje homogenosti varijanse izvršeno je testom Levene-a. Dobijeni podaci su obrađeni metodom analize varijanse (Statistica Ver. 6.0., 2003). Koeficijenti heritabiliteta su ocenjeni metodom intra-klasne korelacije. Očevi švedskog landrasa uticali su na varijabilnost NBA kćeri u prvom i drugom prašenju (p (lt) 0.05), ali ne i u trećem prašenju. Godina i sezona pripusta nisu uticale na varijabilnost NBA (p>0.05). Procenjeni koeficijenti heritabiliteta za NBA su bili najviši u drugom (0.123), zatim u prvom (0.092) i najniži u trećem prašenju (0.030)

Techno-economic analysis of gas turbine-based chp plant operation under a feed-in tariff system

This paper deals with the techno-economic analysis of gas turbine-based combined heat and power production, within a current local legislation frame for the promotion of such production of energy in the Republic of Serbia. Since the legislation includes plants with electric power below 10 MW, an overview of the relevant technical characteristics for a number of appropriate gas turbines was prepared. The relevant thermodynamic parameters are calculated in order to estimate the economic feasibility of combined heat and power production using these plants. The production cost of useful heat is determined by taking into account the incomes from the sale of electricity to the electric grid under a feed-in tariff. It is compared with the production cost from an equivalent boiler for the separate production of the heat. One of the main objectives is to determine the effectiveness of the implemented legislative measures in the promotion of combined production of heat and power. Clear conclusions were drawn based on the results obtained

Analysis of the motion and stability of the holonomic mechanical system in the arbitrary force field

U cilju dobijanja uvida u rad mašine pre njene montaže i proizvodnje, kao i dobijanja dobre analize, ovaj rad predstavlja detaljna rešenja specifičnog problema iz oblasti analitičke mehanike. Pored numeričkih postupaka u radu, izvršen je i pregled teorijskih osnova. Razne vrste analiza su vrlo česte u mašinskom inženjerstvu, zbog mogućnosti aproksimacije složenih mašina. Za predloženi sistem date su Lagranžove jednačine prve vrste, kovarijantne i kontravarijantne jednačine, Hamiltonove jednačine, generalisane koordinate, kao i uvid u Kulonovu silu trenja. Takođe, rešeni su i uslovi statičke ravnoteže uz pomoć numeričkih i grafičkih postupaka - presekom dve krive. Konačno, razmatrana je i stabilnost kretanja poremećenog i neporemećenog kretanja.In order to give an insight into the work of the machine before the production and assembly and to obtain good analysis, this paper presents detailed solutions to the specific problem occured in the field of analytical mechanics. In addition to numerical procedures in the paper, a review of the theoretical foundations was made.Various types of analysis are very common in mechanical engineering, due to the possibility of an approximation of complex machines. For the proposed system, Lagrange's equations of the first kind, covariant and contravariant equations, Hamiltons equations and the generalized coordinates, as well as insight in Coulumb friction force are provided.Also, the conditions of static equilibrium are solved numerically and using intersection of the two curves. Finally, stability of motion for the disturbed and undisturbed system was investigated

Techno-economic analysis of gas turbine-based chp plant operation under a feed-in tariff system

This paper deals with the techno-economic analysis of gas turbine-based combined heat and power production, within a current local legislation frame for the promotion of such production of energy in the Republic of Serbia. Since the legislation includes plants with electric power below 10 MW, an overview of the relevant technical characteristics for a number of appropriate gas turbines was prepared. The relevant thermodynamic parameters are calculated in order to estimate the economic feasibility of combined heat and power production using these plants. The production cost of useful heat is determined by taking into account the incomes from the sale of electricity to the electric grid under a feed-in tariff. It is compared with the production cost from an equivalent boiler for the separate production of the heat. One of the main objectives is to determine the effectiveness of the implemented legislative measures in the promotion of combined production of heat and power. Clear conclusions were drawn based on the results obtained

Competitive trait anxiety and general self-esteem of athletes according to the sport type and gender

Traditionally, anxiety has been interpreted as a negative emotional state characterized by nervousness, worry, fret, uncertainty and vague fear which could have an adverse effect on sports achievement. On the other hand, sport type and its specific nature and demands, may also be connected with the level of state and trait anxiety. This study aimed to investigate potential differences in the competitive trait anxiety level and general self-esteem according to gender in sports of different contact level. The sample consisted of 1024 (590 males and 434 females) young athletes. Independent variables were sport contact level (non-contact, contact and collision sports) and gender. Dependent variables were measured by the adjusted versions of Sport Competition Anxiety Test and Rosenberg Self-Esteem Scale. Basic descriptive statistics was calculated for all the groups, and the differences between them were established using χ² test and MANOVA. The results suggest significant differences in trait competitive anxiety per sport type, gender and their interaction, and no differences in the general self-esteem level. The current study reveals that not only the intensity but also the intergroup relationship of a sport contact level (non-contact, contact and collision sports) is gender determined. These findings are important in psycho-diagnostic procedure and choosing appropriate coping strategies for athletes

Granični sloj ioniziranog plina na rotacijskim tijelima pri postojanju magnetskog polja

This paper studies ionized gas flow in the boundary layer on bodies of revolution. The present magnetic field is normal to a nonporous contour of the body. The governing boundary layer equations are brought to a generalized form by general similarity method. The obtained equations are numerically solved by finite differences method. Based on the obtained solutions, diagrams of distributions of physical qualities in the boundary layer are given. Conclusions of behaviour of these quantities for the studied ionized gas problem are also drawn.Istraživano je strujanje ioniziranog plina u graničnom sloju na rotacijskim tijelima. Prisutno magnetsko polje je okomito na neporoznu konturu tijela. Polazne jednadžbe graničnog sloja dovedene su na uopćeni oblik metodom uopćene sličnosti u verziji Saljnikova. Dobivene jednadžbe numerički su riješene metodom konačnih razlika. Na osnovu dobivenih rješenja prikazani su dijagrami raspodjela fizikalnih veličina u graničnom sloju. Izvedeni su zaključci o ponašanju ovih veličina kod razmatranog problema strujanja ioniziranog plina

Analysis of the motion and stability of the holonomic mechanical system in the arbitrary force field

U cilju dobijanja uvida u rad mašine pre njene montaže i proizvodnje, kao i dobijanja dobre analize, ovaj rad predstavlja detaljna rešenja specifičnog problema iz oblasti analitičke mehanike. Pored numeričkih postupaka u radu, izvršen je i pregled teorijskih osnova. Razne vrste analiza su vrlo česte u mašinskom inženjerstvu, zbog mogućnosti aproksimacije složenih mašina. Za predloženi sistem date su Lagranžove jednačine prve vrste, kovarijantne i kontravarijantne jednačine, Hamiltonove jednačine, generalisane koordinate, kao i uvid u Kulonovu silu trenja. Takođe, rešeni su i uslovi statičke ravnoteže uz pomoć numeričkih i grafičkih postupaka - presekom dve krive. Konačno, razmatrana je i stabilnost kretanja poremećenog i neporemećenog kretanja.In order to give an insight into the work of the machine before the production and assembly and to obtain good analysis, this paper presents detailed solutions to the specific problem occured in the field of analytical mechanics. In addition to numerical procedures in the paper, a review of the theoretical foundations was made.Various types of analysis are very common in mechanical engineering, due to the possibility of an approximation of complex machines. For the proposed system, Lagrange's equations of the first kind, covariant and contravariant equations, Hamiltons equations and the generalized coordinates, as well as insight in Coulumb friction force are provided.Also, the conditions of static equilibrium are solved numerically and using intersection of the two curves. Finally, stability of motion for the disturbed and undisturbed system was investigated