Issue 2013-1.
http://arhiva.nara.ac.rs/handle/123456789/55
www.jageng.agrif.bg.ac.rs/files/casopis/PT_01-2013.pdf2022-12-03T23:40:25ZRespiratory Behaviour of Mature Light Green Guava (Psidium Guajava L.) under Closed System
http://arhiva.nara.ac.rs/handle/123456789/546
Respiratory Behaviour of Mature Light Green Guava (Psidium Guajava L.) under Closed System
Singh, Ranjeet; Giri Kumar, Saroj; Kulkarni, Sitaram
Respiratory behavior is an important aspect in designing and operating systems such as controlled and modified atmosphere storage that will extend the shelf life of the perishable produce. The respiration rate and respiratory quotient of fresh Guava (Psidium guajava L. cv. ‘Safeda’) fruit harvested at the mature light-green stage were determined under closed system at 5, 10, 15, 20, 25 and 35°C (ambient) temperatures. The respiration rate based on carbon dioxide production in aerobic condition decreased about 46% relative to air atmosphere. However the oxygen consumption sharply reduced to 31% relative to air atmosphere at 25°C temperature. The results suggest that, the respiration rate of Guava increased with temperature and decrease with storage time. Results of the study can be applied to design suitable packaging system for shelf life extension of Guava.; Respiratorno ponašanje je važan aspekt u projektovanju i rukovanju sistemima kao što je kontrolisana i modifikovana atmosfera skladišta koja će produžiti period skladištenja. Stepen respiracije i koeficijent respiracije sveže guave (Psidium guajava L. cv. ‘Safeda’), ubrane u zreloj svetlo-zelenoj fazi, određeni su u zatvorenom sistemu pri ambijentalnim temperaturama od 5, 10, 15, 20, 25, 30 i 35°C. Stepen respiracije zasnovan na proizvodnji ugljendioksida u aerobnim uslovima opao je za 46% u odnosu na atmosverski vazduh. Potrošnja kiseonika se značajno smanjila na 31% u odnosu na atmosverski vazduh pri temperaturi od 25°C. Dobijeni rezultati upućuju na zaključak da se stepen respiracije guave povećava sa povećanjem temperature, a smanjuje sa produženjem vremena skladištenja. Rezultati ovih istraživanja mogu se primeniti pri projektovanju optimalnih sistema za pakovanje kojima bi se produžio period skladištenja guave.
Mechanized Harvesting of Leafy Parsley Crops in the Region of South Banat
http://arhiva.nara.ac.rs/handle/123456789/545
Mechanized Harvesting of Leafy Parsley Crops in the Region of South Banat
Radojevic, Rade; Petrovic, Dragan; Tomantschger, Kurt; Radojevic, Mirjana
So far, many types, styles and sizes of mowing equipment has been developed and introduced in the agricultural practice. Therefore, leaf crops harvesting seems to be easier to mechanize with respect to other cultivars. However, keeping the leaf matter clean and loaded into a dryer without contaminants limits the kind of mechanization that can be used.
In this paper is given a general review of Parsley (Petroselinum crispum) crops properties, possible benefits of its applications and basic principles of mechanized growing technology. In addition a simplified agroeconomical calculation of the production costs against possible income from sold vegetables, based on current prices expressed in euros is also provided. This way, the production of Parsley herbs is justified from medical, nutritive, culinary and economical points of view.
Finally, results of testing three harvesters of different design, applied for collecting and preparation of parsley leaves at parcels in the region of south Banat (North Serbia) are presented and analysed. Measurements comprehended following working parameters: harvester velocity, loss of acquired crop and cutting lengths distribution of parsley leafs.; Do sada je razvijen i uveden u poljoprivrednu proizvodnju veliki broj tipova i konstrukcija mašina za košenje. Stoga se čini da je mehanizovanje žetve lisnatih useva lakše u poređenju sa ostalim kulturama. Ipak, očuvanje čistoće lisnatih useva i njihov utovar u sušare bez neželjenih kontaminanata ograničava vrstu opreme koja se može koristiti. U radu je prikazan opšti pregled opreme i postupaka za mehanizovano ubiranje peršuna (Petroselinum crispum). Na osnovu uprošćene ekonomske analize, zasnovane na tekućim cenama u Srbiji izraženim u evrima, potvrđena je opravdanost uzgoja ove poljoprivredne kulture sa ekonomske tačke gledišta. Konačno, prikazani su i analizirani rezultati uporednog testiranja tri kombajna različite kontrukcije, primenjene za sakupljanje i pripremu lišća peršuna na parcelama u regionu južnog Banata (severna Srbija). Merenjem su obuhvaćeni: brzina kombajna, gubici sakupljenog useva i raspodela dužina isečenih frakcija peršuna.
Effect of Agricultural Navigation Without RTK Correction on Spring Sowing
http://arhiva.nara.ac.rs/handle/123456789/544
Effect of Agricultural Navigation Without RTK Correction on Spring Sowing
Petrov, Petar; Ishpekov, Stoyan; Komitov, Georgy; Kachorova, Teodora
It is carried out a comparative investigation of seed drill guiding accuracy in two ways. In the first way the drill is guided by a conventional disk marker and in the second way - by agricultural navigation without RTK correction. It is found that the usage of agricultural navigation lead to more straight rows and reduction of the fuel consumption, but the distance between drill tracks exceeds the row width about 26 %, because of low level of navigation accuracy.; Uporedno ispitivanje preciznosti setvene navigacije je izvedeno na dva načina. U prvom testu sejalica je navođena konveniconalno upotrebom diskosnog markera, a u drugom testu putem poljoprivredne navigacije bez RTK korekcije. Utvrđeno je da upotreba poljoprivredne navigacije vodi do pravilnijih redova i smanjenja potrošnje goriva, ali i da razmak između prohoda sejalice prekoračuje širinu između redova za oko 26% zbog niske preciznosti navigacije.
Discrete Element Method (DEM) Modelling of Cohesive Soil-Tool Interaction
http://arhiva.nara.ac.rs/handle/123456789/543
Discrete Element Method (DEM) Modelling of Cohesive Soil-Tool Interaction
Kotrocz, Krisztian; Tamas, Kornel; Kerenyi, Gyorgy
The soil tool interaction is an important role in modern agricultural researches. In this paper a cultivation tine tool was simulated in operation with the working speed of 1 m s-1 and working depth of 20 cm using discrete element method (DEM). The parallel bond model was used to demonstrate the cohesive behaviour of the soil. Three analyses were created with different material properties and during the simulations the draft force was measured to compare it with soil bin tests’ results. After the soil tool analyses three tri axial tests were performed with the same material properties to measure the cohesion and the internal friction angle.; Interakcija između zemljišta i oruđa ima važnu ulogu u savremenim poljoprivrednim istraživanjima. U ovom radu je prikazana simulacija rada noža radnog organa za obradu zemljišta čija je radna brzina 1 m s-1 a radna dubina 20 cm korišćenjem modeliranja metodom diskretnih elemenata (DEM). Korišten je paralelan model da bi se pokazalo kohezivno ponašanje zemljišta. Napravljene su tri analize sa različitim materijalnim osobinama i tokom simulacije merena je vučna sila da bi se uporedila sa rezultatima testova u zemljišnom bazenu. Posle analize zemljište – oruđe, izvedena su tri tro-aksijalna testa sa istim osobinama materijala u cilju merenja kohezije i ugla unutrašnjeg trenja.