2,605 research outputs found
High-bay warehouse analysis based on influence of stochastic parameters
U radu je analizirana familija visokoregalnih skladiÅ”ta sa jednim ureÄajem za opsluživanje. Ciklus rada, kao osnovni element sistema, proraÄunat je prema FEM propisu sa posebnim osvrtom na promenu brzine kretanja ureÄaja za opsluživanje u vremenu. RazliÄite teorijske raspodele za modeliranje dolaznog toka, opsluživanja i otkaza su koriÅ”Äene u radu za odreÄivanje stohastiÄkog uticaja na performanse skladiÅ”nog sistema. Ostali uticaji na performanse skladiÅ”nog sistema su obuhvaÄeni preko promene optereÄenja sistema. Kombinacija oba uticaja i njihova promena dovode do zakljuÄka o stohastiÄkom ponaÅ”anju posmatranih performansi sistema prikazanih preko razliÄitih teorijskih raspodela. Posebno je razvijen simulacioni model koji je koriÅ”Äen za analizu rada skladiÅ”nih sistema.A group of high-bay warehouses with one servicing device is analyzed. Working cycle of servicing device is calculated upon FEM regulation, using optimal change of velocity in time. Different theoretical distributions for arrival rate, servicing flow and failure were used, in this paper, for determining stochastic influence on warehouse system performances. The other influence on warehouse system performances is taken through offered load of the system. Combination of both influences and variety of each brought up the conclusion about stochastic behavior of observed system performances presented by theoretical distributions. Developed simulation model was used for analysis of warehouse system work
Principi razvoja stoÄarstva u Republici Srbiji
Livestock production is an important branch of agriculture in the Republic of Serbia because it provides necessary products (milk, meat, eggs). In addition, livestock production provides raw materials for food industry and leather industry. Livestock production is expected to provide quality products for export, primarily beef and lamb. There is an opportunity for export of cheese (especially sheep and goat milk cheese) with defined origin and standard of quality. However, based on available data, the situation in livestock production is assessed as negative. In the last years, number of heads of all species of domestic animals has decreased continuously. In several years, Serbia will become member of European Union (EU). This means that livestock production should prepare for competition in the single developed market, without any state trade barriers. Serbia's membership in international organizations, liberalization of trade in livestock products, a small possibility of protection from imports, the implementation of quality standards (HACCP, ISO, Global GAP), reduced levels of domestic support, elimination of export subsidies, increase profitability and ability to be competitive on the international market. Based on these circumstances, it is necessary to build efficient livestock production that can compete in the European market contributing to the growth of farmers and national income.StoÄarska proizvodnja je važna grana poljoprivrede u Republici Srbiji i posmatrani istorijski, oduvek je igrala vodeÄu ulogu u održanju egzistencije stanovniÅ”tva. StoÄarstvo pruža neophodne proizvode (mleko, meso, jaja), a takoÄe obezbeÄuje sirovine za prehrambenu industriju i industriju kože. Od stoÄarske proizvodnje se takoÄe oÄekuje da obezbedi kvalitetne proizvode za izvoz, pre svega govedine i jagnjetine. Priliku za izvoz imaju sir (posebno od ovÄijeg i kozjeg mleka), sa definisanim poreklom i standardom kvaliteta. MeÄutim, na osnovu raspoloživih podataka, situacija u stoÄarstvu se ocenjuje kao negativna. U poslednjih nekoliko godina broj grla svih vrsta domaÄih životinja kontinuirano se smanjuje. Srbija je dobila kandidaturu za Älanstvo u Evropskoj uniji (EU). To znaÄi da bi stoÄarska proizvodnja trebala da se pripremi za konkurenciju na jedinstvenom razvijenom tržiÅ”tu, bez ikakvih državnih trgovinskih barijera. Älanstvo Srbije u meÄunarodnim organizacijama, liberalizacija trgovine stoÄarskih proizvoda, mala moguÄnost zaÅ”tite od uvoza, implementacija standarda kvaliteta (HACCP, ISO, GLOBAL GAP), smanjeni nivo domaÄe podrÅ”ke, eliminisanje izvoznih subvencija,rast profitabilnosti i sposobnost da budu konkurentna na meÄunarodnom tržiÅ”tu, su joÅ” dodatni izazovi sa kojima se suoÄava ili Äe se suoÄiti stoÄarstvo Srbije. Na osnovu ovih okolnosti, neophodno je da se izgrade principi za efikasan razvoj stoÄarske proizvodnje, koja može da se takmiÄi na evropskom tržiÅ”tu i doprinosi rastu poljoprivrede i nacionalnog dohotka
EpidemioloÅ”ki znaÄaj odreÄivanja olova, kadmija, bakra i cinka u kosi i trajnim zubima osoba koje žive u blizini topionice olova
In this paper the content of lead, cadmium, copper and zinc was analysed by atomic absorption spectrophotometry (model Unicam SP 90), in the hair of 200 persons residing in the immediate vicinity (within a distance of 5 km) of a lead smeltery and in a control group of 200 persons living at a distance greater than 10 km from the main air pollution source. Statistically significant differences in the content of the metals were found, the probability range being 0.05-0.01. The concentration of lead, cadmium, copper and zinc in permanent teeth was also analysed in relation to the distance of the residence from the lead smeltery in a group of 111 persons living 1-5 km from it and in 23 persons living in the area 20 to 30 km away. The established differences were statistically significant for all analysed metals with the exception of zinc.Autori iznose rezultate merenja sadržaja olova, kadmija, bakra i cinka u 200 uzoraka kose muÅ”karaca i žena koji žive u blizini topionice olova i u uzorcima kose jednakog broja kontrolnih osoba koje žive daleko od topionice olova. Olovo, kadmij, bakar i cink odreÄivani su atomskom apsorpcijskom spektrofotometrijom. NaÄene su znaÄajne razlike u koncentraciji ispitivanih metala izmeÄu eksponirane i kontrolne skupine (p<0,05 i p<0,01). Koncentracije olova, kadmija, bakra i cinka merene su i u trajnim zubima 111 osoba koje žive u blizini topionice kao i u zubima 23 kontrolne osobe koje žive daleko od topionice. I u ovim su uzorcima utvrÄene statistiÄki znaÄajne razlike u koncentracijama svih metala osim cinka izmeÄu dviju ispitivanih grupa
Challenges of torrential flood risk management in Serbia
Torrential floods are the natural hydrological hazards manifesting as a consequence of extreme rainfall episodes which have a quick response from the watersheds of small areas, steep slopes and intensive soil erosion. Taking in consideration the nature of torrential flood (sudden and destructive occurrence) and the fact they are the most frequent natural hazards in Serbia, torrential flood risk management is a real challenge. Instead of partial solutions for flood protection, integrated torrential flood risk management is more meaningful and effective. The key steps should be an improvement of the legal framework on national level and an expansion of technical and biological torrent control works in river basins. Consequences for society can be significantly reduced if there is an efficient forecast and timely warning, rescue and evacuation and if affected population is educated about flood risks and measures which can be undertaken in case of emergency situation. In this paper, all aspects of torrential flood risk management are analyzed
Kako u Srbiji poveÄati proizvodnju juneÄeg, jagnjeÄeg i svinjskog mesa namenjenog domaÄim potrebama i izvozu
The present situation in livestock production and production of meat is presented in this paper, as well as directions for future work aimed at bringing changes to this branch of economy. In the last decade, a drop in the number of animals was recorded of approx. 2 to 3% at annual level. Also, drop in production of meat was recorded from 444.000 tons (1990) to 384.000 tons (2010). In order to have planned progress in production of meat it is necessary to define more clearly breeding goals with precise determination of all economically relevant and indicator traits. In addition to growth and body development traits which have so far been in focus of selection work, for production of meat also maternal traits are important, food conversion and quantity and quality traits of carcasses and meat.DugoroÄna koncepcija razvoja stoÄarstva treba da se temelji na efikasnosti proizvodnje mesa, preko organizovanja farmera. Za uspeÅ”no organizaciono i ekonomsko jaÄanje farmera važan je pravilan izbor poslovnog povezivanja. Za brdsko planinska podruÄja naÅ”e zemlje, u kojima nema organizovanih otkupnih i preraÄivaÄkih kapaciteta i koja su udaljena od gradskih centara, veoma interesantan oblik povezivanja Äe biti formiranje novih malih preradnih kapaciteta. Stabilne i unapred poznate cene za proizvode stoÄarstva, kao i dobro postavljeni pariteti cena garancija su za stabilno stoÄarstvo. NaÅ”a dosadaÅ”nja iskustva u unapreÄenju stoÄarstva i ostvareni rezultati u svetu, transfer tehnologija, sve viÅ”e nas upuÄuju da je za brže ukupno poboljÅ”anje stoÄarstva neophodna bolje organizovana i pojaÄana struÄna i nauÄna infrastruktura. U Srbiji je 2010-godine i pored manjeg broja stoke proizvedeno ukupno 384.000 tona juneÄeg, svinjskog i jagnjeÄeg mesa, Å”to je za 3,3% viÅ”e nego u 2009. godini, odnosno 6,3 odsto viÅ”e nego Å”to je bila proseÄna proizvodnja od 2001. do 2009. godine. U Srbiji u 2010. bila manja proizvodnja goveÄeg, juneÄeg i teleÄeg mesa za 4,4 odsto i ovÄijeg i jagnjeÄeg mesa za 7,1 odsto, dok se za 6,8 odsto viÅ”e proizvodilo svinjsko. 2010-godine, u poreÄenju sa proseÄno ostvarenom proizvodnjom u periodu od 2001. do 2009. proizvedeno je viÅ”e svih vrsta mesa: svinjskog mesa za 3,1%, goveÄeg i juneÄeg mesa za 7,5, i ovÄijeg i jagnjeÄeg mesa za 15%. Sva domaÄinstva koja se ozbiljnije bave govedarskom proizvodnjom trebalo bi u narednom periodu organizovati kao gazdinstva za tržiÅ”nu proizvodnju mleka, gazdinstva za tržiÅ”nu proizvodnju tovne junadi i gazdinstva za kombinovanu tržiÅ”nu proizvodnju mleka i junadi za klanje. Osnovnu pažnju u programima razvoja ovÄarstva treba posvetiti porodiÄnom gazdinstvu i novim tehnologijama koje se bave intenziviranjem proizvodnje mesa, mleka i vune na farmama ovaca. Specijalizovani farmeri za meso, odnosno mleko treba da poseduju od 100-500 grla ovaca, kao i odgovarajuÄu infrastrukturu. Farmeri trojnog smera proizvodnje su tradicionalna domaÄinstva koja drže do 20 ili 50 ovaca. Njima treba obezbediti kvalitetan priplodni materijal i svaku drugu pomoÄ u cilju poveÄanja njihove proizvodnje. PorodiÄne farme bi u narednom desetogodiÅ”njem periodu trebale da drže 50 a zatim do 100 krmaÄa i tove 1000 i viÅ”e tovljenika. Sve to bi moglo dovesti do poveÄanja proizvodnje svinjskog mesa po proseÄnoj godiÅ”njoj stopi od 2 do 2,5%. Neophodno je odabrati najbolje farme kako bi se formirali elitni, umnožavajuÄi (reproduktivni) i proizvodni (komercijalni) zapati u piramidalnoj organizaciji proizvodnje priplodnih grla i tovljenika
MoguÄnosti stoÄarstva Srbije - perspektiva i buduÄnost
The paper describes the state of the livestock production in the Republic of Serbia including preliminary results from the 2012 census: according to preliminary data, 908.990 heads of cattle, 3.403.288 pigs, 1.729.278 sheep and 235.576 goats are reared in Serbia. Structural and institutional measures, and measures of credit support should be the main instruments for achieving the goals of progress in animal husbandry. Activities in the breeding-selection work should be carried out in accordance with the recommendations of international organizations (ICAR, INTERBULL, EAAP). One of the most important outcome of these activities should result in a level of over 80% of the total population of cattle, pigs, sheep and other species of domestic farm animals in Serbia included in the control of production performance (presently between 25 and 30%). Genetic improvement of cattle, sheep and pigs (milk, meat) is very complex. More efficient use of reproductive technologies (AI - artificial insemination and embryo transfer ET, etc.), also of methods for evaluation of breeding value of farm animals through new methods of evaluation of breeding value of cows and breeding bulls will contribute to faster genetic improvement of production traits of these species of domestic animals. New knowledge in mapping and gene transfer, marker assisted selection, in vitro embryo development, embryo cloning, sexing, etc., are improving rapidly, with new technologies being developed permanently. Breeding/improvement of cattle, sheep and pigs in through breeding - selection work should facilitate further improvement of fertility traits, growth rate, feed efficiency, carcass quality (higher percentage of muscle tissue in the body), the quality of milk and meat, resistance to disease and stress, etc.PoÄetkom 2013. godine dobijeni su preliminarni rezultati popisa poljoprivrede u Republici Srbiji, obavljenog 2012. godine. Ukupan broj goveda je 908.990, svinja 3.403.288, ovaca 1.729.278 i koza 235.576 grla.. PoveÄanje konkurentnosti stoÄarstva Srbije se može ostvariti kreiranjem uslova za tržiÅ”no okruženje i putem investicija, kako u znanje, tako i u opremu. Zbog toga strukturne i institucionalne mere, kao i mere kreditne podrÅ”ke treba da budu glavni instrumenti za ostvarenje ovog cilja. Aktivnosti u odgajivaÄko-selekcijskom radu treba da se sprovode u skladu sa preporukama meÄunarodnih organizacija (ICAR, INTERBULL, EAAP i druga). Jedan od najvažnijih rezultata ovog rada treba da prouzrokuje nivo od preko 80% ukupne populacije goveda, svinja, ovaca i ostalih vrsta domaÄih životinja u Srbiji bude obuhvaÄeno kontrolom proizvodnih svojstava (sada izmeÄu 25 i 30%). Status i ciljevi oplemenjivanja goveda u Srbiji. Genetsko unapreÄenje goveda (mleko,meso) je vrlo kompleksno. Efikasnije koriÅ”Äenje reproduktivnih tehnologija (VO-veÅ”taÄko osemenjavanje i ET-embriotransfer i dr.) i koriÅ”Äenje metoda za procenu odgajivaÄke vrednosti domaÄih životinja preko novih metoda ocene priplodnih vrednosti bikova i krava Äe doprineti bržem genetskom unapreÄenju mleÄnosti krava. Nova saznanja u mapiranju i transferu gena, selekciji preko markera, in vitro razvoju embriona, seksiranju i kloniranju embriona i dr. OdgajivaÄki ciljevi-simentalska rasa, proseÄna proizvodnja mleka u standardnoj laktaciji preko 6 000 kg; HolÅ”tajn frizijska rasa u standardnoj laktaciji preko 8 000 kg. Melezi iz ukrÅ”tanja domaÄih krava nižih proizvodnih sposobnosti i bikova tovnih rasa, francuskih, italijanskih, engleskih. OdgajivaÄki ciljevi ovakvog oplemenjivaÄkog rada i koriÅ”Äenje heterozis efekta je stvaranje takvih genotipova koji Äe omoguÄiti zavrÅ”nu telesnu masu meleza F1, junadi od preko 550 kg, proseÄni dnevni prirast u tovu preko 1500 g, randman toplih polutki preko 60%, sadržaj miÅ”iÄa u trupu od preko 65%. Status i ciljevi oplemenjivanja ovaca u Srbiji. Oplemenjivanje u cilju poveÄanja proizvodnje mesa treba da omoguÄi dobijanje jagnjadi sa veÄim dnevnim prirastom (preko 300 g), veÄe zavrÅ”ne mase tela sa 90 dana uzrasta (preko 28 kg), kao i veÄeg randmana trupa, viÅ”e od 58%). Problem prelaska na policikliÄnost i oplodnju ovaca u toku cele godine obavio bi se na dva naÄina: genetiÄki, koriÅ”Äenjem ukrÅ”tanja rasa koje manifestuju estrus izvan normalne sezone (dorzet horn, il de france i romanovska) primenom metoda stimulacije, tj. indukcijom i sinhronizacijom estrusa.Tako bi se stvorili uslovi za primenu intenzivnog sistema jagnjenja dva jagnjenja u jednoj godini odnosno tri jagnjenja u dve godine. Sistem jagnjenja, sistem ukrÅ”tanja, selekcija i linijsko odgajivanje, zatim skraÄenje post partum intervala i poveÄanje indeksa jagnjenja, kao i broja jagnjadi pri roÄenju, rano zaluÄenje jagnjadi, koriÅ”Äenje metode veÅ”taÄkog osemenjavanja, automatskih maÅ”ina za dojenje, odgajivanje jagnjadi uspeÅ”nom zamenom za mleko i tov jagnjedi od 30 - 45 kg sa 90 do 120 dana. Status i ciljevi oplemenjivanja svinja u Srbiji. Oplemenjivanje svinja u cilju unapreÄenja mesnatosti preko odgajivaÄko-selekciojskog rada treba da omoguÄi dalje poboljÅ”anje osobina plodnosti, brzine porasta, iskoriÅ”Äavanja hrane, kvaliteta trupa (veÄi procenat miÅ”iÄnog tkiva u trupu), kvaliteta mesa i otpornosti svinja na bolesti i stres. OdgajivaÄko-selekcijskim radom neophodno je: poveÄati genetski potencijal postojeÄih mesnatih rasa i meleza svinja, raditi na stvaranju linija unutar Äistih rasa primenom divergentne selekcije, kako bi se kasnije njihovim ukrÅ”tanjem ispoljivo veÄi heterozis efekat. Cilj selekcije treba da bude poveÄanje miÅ”iÄnog tkiva u najvrednijim delovima trupa: but, pleÄka i kare. OdgajivaÄki program u naÅ”oj zemlji predviÄa ukrÅ”tanje landrasa (Å”vedski, holandski,) i velikog jorkÅ”ira radi proizvodnje nazimica F1 generacije. One se posle toga ukrÅ”taju sa nerastovima treÄe rase (terminalna rasa nerastova: hempÅ”ir, durok, pietren, nemaÄki i belgijski landras) ili nerastovima F1 generacije. PR Projekat Ministarstva nauke Republike Srbije, br. TR-31053
Lawton, Michael T: Seven aneurysms: Tenets and techniques for clipping: Thieme 2011, ISBN 978-1-60406-054-6
In this paper, the removal of methylene blue (MB) from aqueous solution by biosorption onto apricot shellshas been investigated through batch experiments. Apricot shells were chosen as a locally available and abundant waste from fruit juice industry. Methylene blue is common pollutant of waste waters from textile industry. The influence of initial MB concentration on biosorption process has been studied. The experimental data have been analysed using Langmuir and Freundlichisotherm models. The Langmuir model better fits to experimental data, which explain monolayer adsorption. Maximum biosorption capacity is 24,31 mg/g. A comparison of the biosorption capacity of waste apricot shells with biosorption capacities of similar adsorbents previously investigated indicates that apricot shells could be a promising biosorbent for removal of MB from aqueous solution
Korelaciona analiza povezanosti proizvodnih osobina kroz tri generacije krava simentalske rase
The relationship between milk production traits over whole lactations was evaluated across three generations of Simmental cows, i.e. between daughters, dams and grand dams, by a phenotypic regression analysis with whole lactation traits in the daughter generation being used as the dependent variables (x1), and those in the dam and grand dam generations being used as the independent variables (x2 and x3). The results were obtained from a sample of 1170 daughters and as many dams and grand dams. The significance of the partial regression coefficients b2 and b3 was separately evaluated by a t-test. An analysis of variance was used to estimate the significance of the simultaneous effect of the production traits of dams and grand dams on the milk production achieved in the daughter generation. The calculated value of the partial regression coefficients for the whole lactation production traits across three generations (grand dams, dams and daughters) and their statistical significances determined by the t and F tests, as well as the regression equations used, suggested that the effect of the grand dam generation on the milk production traits in granddaughters was substantially lower than the effect of dams. The calculated partial regression coefficients (b2 and b3) were positive and statistically very significant (P lt 0.01), excepting the regression coefficients b3 for lactation length and b2 for milk fat content that were not statistically significant (P>0.05). A very significant change (P lt 0.01) was observed in all production traits in the daughter generation as simultaneously affected by the traits in the dam and grand dam generations.Povezanost osobina mleÄnosti u punim laktacijama analizirana je izmeÄu tri generacije krava simentalske rase, odnosno izmeÄu kÄerki, majki i baba, fenotipskom regresionom analizom u uslovima kada su osobine punih laktacija u generaciji kÄerki posmatrane kao zavisno (x1), a osobine punih laktacija u generaciji majki i baba kao nezavisno promenljive (x2 i x3). Rezultati su dobijeni na uzorku od po 1170 kÄerki, majki i baba. PojedinaÄno ispitivanje znaÄajnosti delimiÄnih regresionih koeficijenata b2 i b3 izvrÅ”eno je t-testom, a analizom znaÄajnosti istovremenog uticaja proizvodnih osobina majki i baba na ostvarenu proizvodnju kod kÄerki izvrÅ”ena je metodom analize varijanse. Na osnovu izraÄunate vrednosti delimiÄnih regresionih koeficijenata za proizvodne osobine celih laktacija kroz tri generacije (babe, majke i kÄerke) i njihove statistiÄke znaÄajnosti odreÄene t i F testom, kao i jednaÄina regresije konstatovano je da je uticaj generacije baba na proizvodnju unuka znatno manji u odnosu na uticaj kojeg imaju majke. Svi izraÄunati delimiÄni koeficijenti regresije (b2 i b3) bili su pozitivni i statistiÄki vrlo znaÄajni (P lt 0.01), izuzimajuÄi koeficijent regresije b3 kod trajanja laktacije i b2 kod sadržaja mleÄne masti koji nisu bili statistiÄki znaÄajni (P>0.05). ZnaÄajnost promena svih posmatranih proizvodnih osobina u generaciji kÄerki pri istovremenom uticaju tih osobina iz generacije majki i baba bila je vrlo visoka (P lt 0.01)
Uticaj paragenetskih faktora na reproduktivne osobine krava simentalske rase
The examination was made on the effect of systematic factors (parturition group, calving season, birth type, calf gender, and birth type-calf gender interaction) and age at first conception on the expression of reproductive traits (gestation length, service period, fertility intensity and calf birth weight) in 143 Simmental cows. The overall mean (Ī¼) for gestation length, service period, intercalving period and calf birth weight was 284.14 days, 153.82 days, 416.92 days and 35.40 kg, respectively. The parturition group effect on all fertility traits was highly significant (P lt 0.01). The calving season statistically significantly (P lt 0.05) affected the intercalving period and calf birth weight. Birth type induced very significantly longer gestation (P lt 0.01) and higher calf birth weight in singles (P lt 0.01) and significantly longer service period in twins (P lt 0.05). Calf gender had a very significant effect (P lt 0.01) only on calf birth weight, and the interaction between birth type and calf gender significantly affected gestation duration only (P lt 0.05). The regression effect of age at first conception on all fertility traits was not significant (P>0.05).Na ispoljenost reproduktivnih osobina (dužina bremenitosti, servis period, intenzitet plodnosti i masa teladi pri roÄenju) kod 143 krave simentalske rase, ispitivan je uticaj sistematskih faktora (grupe partusa, sezone telenja, tip roÄenja, pol teladi i interakcija tipa roÄenja i pola teladi) i uzrasta pri prvoj oplodnji. OpÅ”ti prosek (Ī¼) za dužinu bremenitosti iznosio je 284.14 dana, servis period 153.82 dana, meÄutelidbeni interval 416.92 i masu teladi pri roÄenju 35.40 kg. Uticaj grupe partusa na sve osobine plodnosti bio je visoko znaÄajan (P lt 0.01). Sezona telenja statistiÄki znaÄajno (P lt 0.05) je uticala na meÄutelidbeni interval i masu teladi pri roÄenju. Tip roÄenja uslovio je vrlo znaÄajno dužu bremenitost (P lt 0.01) i veÄu masu teladi pri roÄenju kod jedinaca (P lt 0.01) i znaÄajno duži servis period kod blizanaca (P lt 0.05). Pol teladi vrlo znaÄajno je uticao (P lt 0.01) samo na masu teladi pri roÄenju, dok je interakcija tipa roÄenja i pola teladi znaÄajno uticala samo na trajanje bremenitosti (P lt 0.05). Regresijski uticaj uzrasta pri prvoj oplodnji na sve osobine plodnosti nije bio signifikantan (P>0.05)
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