Variability in ejaculation rate and libido of boars during reproductive exploitation

The main objective of the study was to evaluate variability in the ejaculation rate and libido of boars under various genetic and non-genetic influences. A total of 7171 semen samples were collected from Swedish Landrace, Large White and Duroc boars reared under commercial production conditions. Time spent in preparing or collecting, constituted the period from the entry of boars into the room for collecting semen to onset of ejaculation. Ejaculation rate was defined as the volume of sperm extracted (mL) per unit of time (min). The index of boar libido was defined as the relationship between productive (duration of ejaculation) and unproductive (time spent in preparing to collect/jump) periods. Average values of the interval between two collections, age of boar at collection, time spent in preparing for collection, duration of ejaculation, volume of ejaculate, rate of ejaculation and libido index were: 8.83 days, 551.2 days, 3.56 min, 6.06 min, 231.9 mL, 37.67 mL/min and 1.76, respectively. Ejaculate traits and libido varied according to breed, season and collector, with the exception of seasonal variability of duration of ejaculation. The regression effect of the interval between two collections of ejaculate and age of boar at collection was not statistically significant only for duration of preparing for collection. Unlike the ejaculation rate, during the summer and autumn periods, boars exhibited weaker libido than in winter and spring. Duroc boars were inferior to the fertile breeds (Swedish Landrace and Large White) in terms of shorter duration of ejaculation, lower volume, lowest rate of ejaculation and weakest libido. Variability of rate of ejaculation and of boar libido indicates the need to include these traits in breeding programmes and the possibility of improving these traits

Sensory properties and fatty acids profiles of fermented dry sausages made of pork meat from various breeds

In this study, the parallel examinations on fatty acid profiles and sensory properties of fermented dry sausages are presented. Three types of kulen and sremska sausages were made, which varied depending on the percentage of meat and fat derived from different pig breeds: autochthonous (Swallow-Belly Mangalitsa and Moravka) and commercial (Swedish Landrace). In sausages made from meat of commercial pig breed, the highest cholesterol content was detected. However, sausage made from the Mangalitsa pork meat contained higher levels of monounsaturated fatty acid (MUFA) and unsaturated fatty acid (USFA), and lower saturated fatty acid levels (SFA). The level of polyunsaturated (PUFA) in sausage made of Landrace pork meat was significantly higher than levels in other types. These differences between fatty acids were mostly deriving by higher total n-6 PUFA content. In a sausage made of Mangulitsa meat, the values of atherogenic (IA) and thrombogenic (IT) health lipid indexes are lower. Kulen and sremska sausages made from the Mangalitsa pork meat was superior in terms of colour, odour, taste, after taste and overall acceptability. This study demonstrate that pig breed have an effect on the chemical content, fatty acids profiles and sensory properties of dry fermented sausages

Phenotypic and genetic variability of boar fertility

Fenotipska i genetska varijabilnost plodnosti nerasta ispitivana je na osnovu libida i osobina ejakulata, uspešnosti osemenjavanja, veličine legla plotkinja sa kojima su nerasti pareni i njihovih kćerki. Plodnost nerasta je ispitivana u zavisnosti od rase nerasta (švedski landras-ŠL, veliki jorkšir-VJ i durok-D), kombinacije parenja (čistorasno i ukrštanje), starosti nerasta (četiri klase), starosne kategorije krmača (prva tri prašenja), trajanja perioda od zalučenja legla do oplodnje (≤4, 5, 6, 7-50 dana), godine i sezone (zima, proleće, leto i jesen). Podaci su analizirani primenom General Linear Model procedure. Primenom REML metode izvršena je ocena komponenti varijanse između i unutar nerasta za dve generacije (očevi i sinovi). Ocena koeficijenata heritabiliteta osobina veličine legla kćerki izvršena je metodom intra-klasne korelacije polusestara po ocu. Osobine libida i ejakulata: trajanje pripreme za skok (T), ocena libida (OL), trajanje ejakulacije (E), volumen ejakulata (VOL), gustina (GUS), ocena pokretljivosti nativne sperme (NAT), ocena pokretljivosti razređene sperme (RAZ), broj proizvedenih doza po ejakulatu (BPD) varirale su pod uticajem genetskih i paragenetskih faktora. Za razliku od libida, VOL je ispoljio postepeni rast od 197,87 do 253,07 ml, dok su kvalitativna svojstva ejakulata (GUS; NAT i RAZ) pokazala poboljšanje ili relativno ujednačen nivo ispoljenosti (2,04; 3,98-3,99 i 3,95-3,96) do starosti nerasta oko dve godine. Uticaj visokih letnjih temperatura na libido, produkciju sperme i njenu fertilnu sposobnost bio je negativan. Ocenjeni koeficijenti ponovljivosti za osobine T, OL, E, VOL, GUS, NAT, RAZ i BPD iznosili su: 0,2491; 0,2013; 0,2472; 0,3511; 0,0875; 0,2363; 0,2074 i 0,0667, a pokazuju da se ispitivane osobine mogu poboljšati primenom selekcije. Utvrđene su manje varijanse između nerasta za sve osobine u generaciji sinova, koje nisu rezultat strože selekcije. Sinovi su imali prosečno duže trajanje vremena do skoka i slabiju ocenu libida, što ukazuje na potrebu poboljšanja ispitivanih osobina. Reproduktivna efikasnost nerasta može se ocenjivati na osnovu procenta povađanja (PPO, %) i prašenja (PPR, %). Prosečna vrednost PPO plotkinja parenih sa nerastima tri rase iznosila je 11,70% i varirala je od 4,82% do 28,04%, dok je vrednost PPR prosečno iznosila 81,40% sa variranjem od 63,55% do 90,00%..

Stepped spillway flow: Comparison of numerical and scale models

Tema rada je modeliranje strujnog polja na stepenastom brzotoku brane Bogovina. Analiza je sprovedena na rezultatima dobijenih pomoću: fizičkog modela, empirijskih jednačina i numeričkog modela. Slaganja rezultata empirijskih jednačina i numeričkog modela su u prihvatljivim granicama, dok je primećeno njihovo značajno odstupanje od rezultata merenja na fizičkom modelu. Uzrok ovih razlika je proces samo-aeracije mlaza. Budući da je ovaj proces važan za ovaj vid strujanja, nepohodno je poboljšati postojeće empirijske zavisnosti i numeričke modele.This paper deals with flow modelling of the stepped spillway for the Bogovina dam. The analysis was conducted using three approaches: scalemodelling, empirical equations and numerical modelling. An acceptable agreement was achieved between the empirical equations and the numerical model results, while both of them exhibit considerable differences when compared to scale-model. These discrepancies can be contributed to the difficulties in modelling the process of air-entrainment. Since air-entrainment is important for providing good estimates, existing empirical equations as well as numerical models require further improvements

Supercritical flow in circular-conduit bends

Analizirano je složeno strujanje koje nastaje u krivini kružnog provodnika pri burnom toku. Ispitivanja su urađena na hidrauličkom fizičkom modelu, kao i na numeričkom modelu, zasnovanom na programskom paketu ANSYS (Fluent). Prikazani su rezultati dobijeni na pomenuta dva modela, sa komentarima i preporukama za njihovu primenu. Predložene su jednostavne zavisnosti kojima se opisuje uticaj zakrivljenosti, skretnog ugla i prilaznih uslova tečenja (dubina i Frudov broj uzvodno od krivine) na razmatrano tečenje.Complex flow pattern occurring in a circular conduit bend with supercritical flow is analyzed. The research was done by a scale (physical hydraulic) model, and a numerical model developed in ANSYS (Fluent) surrounding. The results obtained by physical (scale) and numerical models are presented, with comments and recommendations for their application. Simple empirical relationships were developed, describing the effects of the bend curvature, bend deflection angle and approaching flow conditions (depth and Froude number upstream from the bend) on the considered flow

Energy loss in a circular-conduit bends with supercritical flow

U radu su analizirani gubici energije u krivini koji nastaju pri burnom tečenju u provodniku kružnog poprečnog preseka. Urađena su hidraulička modelska ispitivanja, na osnovu kojih su određeni koeficijenti gubitka energije. Predloženi su izrazi za koeficijent gubitka u zavisnosti od karakteristika krivine (skretnog ugla i zakrivljenosti). S obzirom da u literaturi ne postoje izrazi kojima se opisuje ovakav gubitak energije u krivini, predložene zavisnosti su upoređene sa izrazi a ko i se odnose na tečenje pod pritiskom. Na kraju rada su date preporuke i zaključci.In this paper the energy loss in a circular conduit bend with supercritical flow is analyzed. Based on the test results obtained by a scale model, the energy-loss coefficient has been determined. Simple empirical relationships were developed, describing the effects of the bend curvature and bend deflection angle on the energy losses. Since no expressions for supercritical flow bend energy-loss coefficient exist, proposed empirical relationships have been compared with expressions relating to pressurized flow

Burno tečenje u krivini provodnika kružnog poprečnog preseka

Complex flow pattern occurring in a circular conduit bend with supercritical flow is analyzed. The research was done by a scale (physical hydraulic) model, and a numerical model developed in ANSYS (Fluent) surrounding. The results obtained by physical (scale) and numerical models are presented, with comments and recommendations for their application. Simple empirical relationships were developed, describing the effects of the bend curvature, bend deflection angle and approaching flow conditions (depth and Froude number upstream from the bend) on the considered flow.Analizirano je složeno strujanje koje nastaje u krivini kružnog provodnika pri burnom toku. Ispitivanja su urađena na hidrauličkom fizičkom modelu, kao i na numeričkom modelu, zasnovanom na programskom paketu ANSYS (Fluent). Prikazani su rezultati dobijeni na pomenuta dva modela, sa komentarima i preporukama za njihovu primenu. Predložene su jednostavne zavisnosti kojima se opisuje uticaj zakrivljenosti, skretnog ugla i prilaznih uslova tečenja (dubina i Frudov broj uzvodno od krivine) na razmatrano tečenje

Supercritical flow in circular pipe bends

U radu je analizirano složeno strujanje koje nastaje u krivini zatvorenog provodnika u burnom toku. Ispitivanja su urađena na hidrauličkom fizičkom modelu, ali i na numeričkom, formiranom u okviru programskog paketa Ansys (Fluent). Rezultati sa hidrauličkog modela su korišćeni za kalibraciju numeričkog, pa je u okviru rada prikazano poređenje rezultata dobijenih na pomenuta dva modela, sa komentarima i preporukama za njihovu primenu. Na osnovu izvršenih ispitivanja date su jednostavne zavisnosti kojima se opisuje uticaj veličine skretnog ugla i prilaznih uslova tečenja (dubina i Frudov broj uzvodno od krivine) na razmatrano tečenje.In this paper a complex flow pattern occurring in a closed conduit bend with supercritical flow is analyzed. The research was done by a scale (physical hydraulic) model, and a numerical model developed in Ansys (Fluent) program surrounding. This article compares the results obtained by numerical and physical (scale) models, providing comments and recommendations for their application. Based on these results, simple empirical relationships were developed, describing the effects of the bend deflection angle and approach flow conditions (non dimensional depth and the Froude number upstream from the bend) on the considered flow

Analysis of Strengthening Variants of Existing Masonry Buildings for Seismic Resistance - Case Studies of Typical Residential Buildings in Niš

The revitalization of existing masonry buildings, built decades ago, is a very topical and complex structural engineering issue, especially when the building was built in the area of significant seismic activity. A large number of masonry buildings in the city of Niš, as well as in other places in Serbia, were built in the period before the adoption of technical regulations on the design and construction of seismically resistant structures and they are at insufficient safety level in the event of an earthquake. Therefore, it is necessary that structural strengthening meets the seismic resistance requirements laid down in Eurocode 8 or other relevant codes. In order to choose the method of structural strengthening, detailed seismic analyses must be carried out in several variants along with the application of relevant technical regulations. The effects of five analyzed structural strengthening methods were checked against the provisions of Eurocode 8, Part 1 and Part 3, which relate to the recommendations for the geometric characteristics of shear walls, and they were applied on two types of existing masonry buildings in Niš. On the basis of the performed analyses, conclusions were drawn regarding the methodological approach of the assessment of the condition of the structure, its seismic resistance and decision-making on remediation and/or strengthening measures