Klasifikacija poljoprivredne biomase uključuje biomasu dobivenu iz brzo rastućih energetskih usjeva. Jedna od takvih kultura je i višegodišnja trava Miscantus x giganteus koja nakon treće, četvrte ...godine formira gusti sklop s izuzetno visokim i čvrstim izbojma. Stoga se poseban naglasak treba staviti na sustave žetve. U žetvi Miscanthusa uglavnom se koristi mehanizacija za sjenažu i silažu primjenom jednofazne ili višefazne tehnike. Cilj ovog rada je dati pregled sustava za sakupljanje biomase Miscanthus x giganteusa s obzirom i na oblik požete biomase, bilo usitnjene ili/i balirane. Uz primjenu gnojiva, berba biomase je jedini agrotehnički zahvat koji se provodi kada nasada dosegne punu zrelost te ga je potrebno provesti uz što manji utrošak energije i gubitak biomase. Zbog povećanog interesa za proizvodnju energije iz biomase trave Miscantus x giganteus dolazi do adaptacije postojeće mehanizacije i razvoja novih, specijaliziranih strojeva.
The aim of this paper was to quantify vertical stress distribution in silty loam soil by applying three combinations of tyre inflation pressures of front and rear wheels of a four-wheel drive tractor ...weighing 3560 kg. The tyres on the tractor were bias-ply, front 11.2-24 and rear 16.9-30, and inflation pressures were 67, 100, and 150% of the recommended pressure. Soil stresses were measured at 10, 30, and 50 cm depths using a stress transducer consisting of ten sensors with a 10 cm distance between sensor centres. Decrease in tyre inflation pressure resulted in a decrease of maximum soil stress at all measured depths. Tyre inflation pressures greatly influenced soil stresses measured in the topsoil. Maximum soil stress in the topsoil depth below front wheel tyres was significantly higher than that below rear wheel tyres. There were no significant differences between tyre contact areas at recommended, high, and low tyre inflation pressures.
Cilj ovog rada bio je utvrditi utjecaj sustava držanja na fizikalna, morfološka i mehanička svojstva jaja japanskih prepelica (Coturnix coturnix japonica). Ukupno je prikupljeno 240 jaja japanskih ...prepelica koje su držane u dva različita sustava držanja: u kaveznom sustavu i u sustavu volijera (120 jaja iz svakog sustava). Jaja iz kaveznog sustava bila su značajno (P<0,05) teža od jaja iz sustava volijera (11,85 g nasuprot 10,93 g), a također su bila duža, šira i imala su značajno veći (P<0,05) srednji geometrijski promjer, površinu i volumen. Nije primijećena statistički značajna razlika u sadržaju bjelanjka i žumanjka između jaja iz kaveznog sustava i sustava volijera. Jaja iz sustava volijera imala su značajno veći sadržaj ljuske i čvrstoću ljuske te su zahtijevala veću silu za razbijanje ljuske jajeta. Prosječna sila potrebna za razbijanje ljuske jaja japanskih prepelica iz kaveznog sustava i sustava volijera u sve tri osi iznosila je 14.36 N odnosno 12.70 N.
The paper presents comparison of three soil tillage systems in maize, winter wheat and soybean growing on anthropogenic Albic Luvisol in north-west Slavonia, Croatia, during 1996-1999. Tillage ...systems and implements were: 1. conventional system (CT)-plough, disc-harrow and combined implement, 2. conservation system (RT)-chisel plough and multitiller, 3. no-till system (NT). The aim of testing was comparison of different tillage systems energy requirement and its influence on yield. Results indicate that conventional tillage (CT) system was the greatest energy consumer with 1813.10 MJ ha-1. Comparing to conventional tillage (CT) system, conservation (RT) system with chisel plough and multitiller spent 1133.14 MJ ha-1or 37.5 % less, while no-till (NT) system required even 85.1 % less energy or 270.13 MJ ha-1. In the first season the greatest yield of maize, 7.78 Mg ha-1, achieved conventional tillage (CT) system while next to it was conservation (RT) system with 7.77 Mg ha-1. No-till (NT) system achieved 7.56 Mg ha-1. Second season the greatest yield of winter wheat, 5.89 Mg ha-1, achieved conservation tillage (RT) system. Next to it was conventional (CT) system with 5.75 Mg ha-1, while no-till (NT) achieved 5.73 Mg ha-1. Third season the greatest yield of soybean, 2.71 t ha-1, achieved conservation tillage (RT) system again, while next to it was conventional (CT) system with 2.64 Mg ha-1. No-till (NT) achieved 2.61 Mg ha-1.
Cilj ovog istraživanja bio je usporediti fizikalna, morfološka i mehanička svojstva jaja sakupljenih od dvije pasmine pataka (Pekinška patka i Cherry Valley patka). Uzorak od 120 jaja (60 jaja od ...svake pasmine) prikupljen je od pataka starih godinu dana. Jaja Cherry Valley patke bila su značajno teža (94,23 prema 71.,91 g) nego Pekinške patke (P<0.01), imale su veće dimenzije i veći indeks oblika (73,8 prema 70,16). Nije bilo statistički značajne razlike između specifične težine jaja. Shodno udjelu glavnih komponenata, jaja Cherry Valley patke su imala veći postotak bjelanjka, dok su jaja Pekinške patke imala veći postotak žumanjka i ljuske. Jaja Pekinške patke imala su značajno veći omjer žumanjka i bjelanjka i vrijednost Haugh jedinice (P<0.01). Prosječna sila potrebna za razbijanje jaja Cherry Valley patke u sve tri osi (50,32 N) bila je značajno veća (P<0.01) od prosječne sile potrebne za razbijanje jaja Pekinške patke (42,64 N). Najveća potrebna sila za razbijanje jaja kod obje pasmine ispitane u ovom istraživanju izmjerena je kod opterećenja duž prednje X-osi, dok je najmanja otpornost na silu razbijanja izmjerena duž Z-osi.
The aim of the investigation was to compare and unveil efficiency of electro-hydraulic control (EHR) system to mechanical three point hitch regulation in mouldboard ploughing. Increase of working ...velocity and three point hitch automatic regulation activity decreased depth of ploughing at both regulation systems but electro-hydraulic system done it more accurately since deviation from default value was 10 % less than at mechanical regulation system. Electro-hydraulic three point hitch control system decreased wheel slip up to 30 % in comparison to mechanical regulation system. Net energy requirement at mechanical three point hitch regulation system spent 3 % more energy than electro-hydraulic control system. If wheel slip reduction influenced by electro-hydraulic control system would be added one could account on greater energy savings than previously mentioned value. The greatest working rates were achieved at the greatest working velocity (8,0 km h(-1)), while exactly at that velocity the greatest working rate increase of 3,8 % influenced by electro-hydraulic three point hitch control was noticed.
The objective of this study was to determine the influence of housing system on the physical, morphological, and mechanical properties of Japanese quail (Coturnix coturnix japonica) eggs. A total of ...240 eggs were collected from Japanese quails kept in two different housing systems: cage housing and aviary housing system (120 eggs from each housing system). Eggs from cage housing system were significantly (P<0.05) heavier than eggs from aviary housing system (11.85 g vs. 10.93 g), and were also longer, wider and had significantly (P<0.05) larger geometric mean diameter, surface area and volume. No statistically significant difference in albumen and yolk content was observed between eggs from cage and aviary housing system. Eggs from aviary housing system had significantly higher shell content and shell strength and required greater force to eggshell breaking. The average force required to breaking the shell of Japanese quail eggs from cage and aviary housing system in all three axes was 14.36 N and 12.70 N, respectively.
The aim of this study was to compare various physical and mechanical characteristics of eggs laid by ISA Brown hens kept in two different housing systems: aviary housing and free-range system. Aviary ...housed laying hens laid eggs of statistically significantly higher (Pyolk to albumen ratio (26.80% and 0.446) than eggs from aviary system (24.89 and 0.399). In comparison to eggs from free range system, eggs from aviary housing had higher shell strength and required greater force to rupture egg. The average force required to rupture eggs from aviary housing and free-range system in all three axes was 38.11 N and 36.28 N, respectively.
This study was conducted to evaluate mechanical properties of ten-egg boxes, which are the most commonly used egg boxes in many countries of Central and South-Eastern Europe. Six ten-egg boxes were ...tested, two made of cardboard, two made of expanded polystyrene and two made of general purpose solid polystyrene, each from a different producer. There were no significant differences in basic dimensions between tested boxes of various materials, while the significant differences were occurred in weight and box wall thickness. Test included measuring of vertical forces required for deforming complete box and at particular place for each egg in a box till contact with eggs. According to the obtained results, cardboard boxes can provide the best mechanical protection for eggs. The average force required for deforming complete cardboard box was 83.6% higher than for solid polystyrene box, and even 289.5% higher than for expanded polystyrene box. The average force required for deforming cardboard box at particular place for each egg in a box was 60.8% higher than for polystyrene box, and 74.0% higher than for expanded polystyrene box. The disadvantage of cardboard boxes is that they are not resistant to the impact of moisture as polystyrene boxes and in the case of an increase in box moisture due to storage in inappropriate conditions their mechanical resistance decreases.
PDF
