Upotreba vremensko frekvencijske analize za rano otkrivanje pukotina na jednostupanjskim zupčastim pogonima

The relationships between the existence of gear teeth cracks as a cause and symptoms emerging as housing vibrations that can be detected with signals measured was investigated numerically and experimentally. Experimental measurements on one-stage gear drives have been carried out involving gears built in with different notch length in tooth root. Signals measured as accelerations on gear box house have been analysed with STFT. A new computer programme DSP_Studio has been developed for detecting and measuring the diagnostic signals, and simultaneously for analysing the effect of crack in tooth root. Numerical simulation model of simple gear pair, which incorporates simulation of crack presence in altered tooth stiffness, has been conducted to confirm experimentally obtained results. The experimental results corroborate with the numerical results. The results derived represent an important contribution to early crack detection on one-stage gear drives.Sljedeći rad raspravlja o istraživanju povezanosti pukotine u korijenu zuba, kao uzrok, i simptomima koji se pojavljuju u obliku vibracija na kućištu te ih je moguće očitavati u izmjerenim signalima. U tu svrhu su bila obavljena eksperimentalna mjerenja na izrađenom jednostupanjskom zupčastom pogonu u kom su bili ugrađeni zupčanici sa različito dugim pukotinama u korijenu zuba. Signali, izmjereni u obliku ubrzavanja na kućištu pogona, bili su analizirani u vremenskom, frekvencijskom, kepstralnom te vremensko-frekvencijskom prostoru. Da bi obuhvatili dijagnostičke signale i analizu utjecaja pukotine zuba izradili smo vlastiti kompleksan računalni program DSP_studio, koji predstavlja novost i važan doprinos na području tehničke dijagnostike. Da bi potvrdili rezultate dobivene eksperimentima, izveli smo numeričku simulaciju modela jednostavnog zupčanog para u kojem je bila simulirana prisutnost pukotine u promijenjenom slijedu krutosti zuba. Ustanovili smo dobro slaganje eksperimentalno i numeričko dobivenih rezultata. Dobiveni rezultati predstavljaju doprinos k ranom otkrivanju pukotina na zupčastim pogonima

Modelling of Apple Fruit Growth by Application of Image Analysis

The possibility of RGB image processing and analysis for modelling of the development and growth of apple fruits was investigated during the two seasons under the orchards experiment in the four-years old ‘Golden Delicious’ and ‘Gala’ variety. The fruit detection depended significantly on the size and fruit’s colour of each growing stage, thus the correlation coefficients were continuously increasing from r=0.71 (2001) and r=0.73 (2002) after fruit tinning in June, up to r=0.88 (2001) and r=0.89 (2002) at harvesting in September respectively. The yield at harvest was estimated with the accuracy of 94% and 101% for ‘Golden Delicious’ and with 106% and 92% for ‘Gala’ respectively, whenever based on images captured on June 22 2001 and June 26 2002. Therefore, the image algorithm was proved to be equal or even better method for estimating the yield at harvest than the common ‘Prognosefruit’ method (accuracy 101% and 77% for ‘Golden Delicious’ and 72% and 63% for ‘Gala’ respectively

Upotreba vremensko frekvencijske analize za rano otkrivanje pukotina na jednostupanjskim zupčastim pogonima

The relationships between the existence of gear teeth cracks as a cause and symptoms emerging as housing vibrations that can be detected with signals measured was investigated numerically and experimentally. Experimental measurements on one-stage gear drives have been carried out involving gears built in with different notch length in tooth root. Signals measured as accelerations on gear box house have been analysed with STFT. A new computer programme DSP_Studio has been developed for detecting and measuring the diagnostic signals, and simultaneously for analysing the effect of crack in tooth root. Numerical simulation model of simple gear pair, which incorporates simulation of crack presence in altered tooth stiffness, has been conducted to confirm experimentally obtained results. The experimental results corroborate with the numerical results. The results derived represent an important contribution to early crack detection on one-stage gear drives.Sljedeći rad raspravlja o istraživanju povezanosti pukotine u korijenu zuba, kao uzrok, i simptomima koji se pojavljuju u obliku vibracija na kućištu te ih je moguće očitavati u izmjerenim signalima. U tu svrhu su bila obavljena eksperimentalna mjerenja na izrađenom jednostupanjskom zupčastom pogonu u kom su bili ugrađeni zupčanici sa različito dugim pukotinama u korijenu zuba. Signali, izmjereni u obliku ubrzavanja na kućištu pogona, bili su analizirani u vremenskom, frekvencijskom, kepstralnom te vremensko-frekvencijskom prostoru. Da bi obuhvatili dijagnostičke signale i analizu utjecaja pukotine zuba izradili smo vlastiti kompleksan računalni program DSP_studio, koji predstavlja novost i važan doprinos na području tehničke dijagnostike. Da bi potvrdili rezultate dobivene eksperimentima, izveli smo numeričku simulaciju modela jednostavnog zupčanog para u kojem je bila simulirana prisutnost pukotine u promijenjenom slijedu krutosti zuba. Ustanovili smo dobro slaganje eksperimentalno i numeričko dobivenih rezultata. Dobiveni rezultati predstavljaju doprinos k ranom otkrivanju pukotina na zupčastim pogonima

Kemijsko prorjeđivanje cvjetova jabuke u ekološkoj proizvodnji

An experiment on chemical blossom thinning on apple variety \u27Summerred\u27/ M9 was performed in an experimental plantation in Brdo pri Lukovici. Different chemical thinners were applied on apple’s fruitlets in organic production. The experiment was designed in 7 randomized block with 13 treatments: 1. unthinned trees (as a control), 2. hand thinning in June, 3. 1% NaCl, 4. 1,5% NaCl, 5. 1% CH3COOH, 6. 3% CH3COOH, 7. 3% CaSx, 8. 1% rape oil, 9. 3% rape oil, 10. 3% of sunflower oil, 11. 3% soybean oil, 12. 5% dextrin, 13. emulsifier 100 + OCA 30. Chemical thinners were applied in a phenological stage at peak blooming with a manual knapsack sprayer. The best thinning of fruitlets (similar to hand thinned trees) was observed with 3% rape oil, however, relatively strong russeting of fruit skin was detected in this treatment. Statistically significant reduction of final fruit set also occurred when 1,5% NaCl and 3% soybean oil were applied, but with less fruit russeting.Na eksperimentalnoj plantaži (Brdo pri Lukovici) proveden je pokus kemijskog prorjeđivanja cvjetova jabuke sorte ‘Summerred’ cijepljene na podlozi M9. Cilj eksperimenta bio je ispitati učinke različitih sredstava koji se koriste u jabukama u ekološkoj proizvodnji. U pokusu sa 7 randomiziranih blokova i 13 tretmana proučavan je utjecaj: 1. neprorijeđeno, 2. ručno rijeđeno u lipnju, 3. 1% NaCl, 4. 1,5% NaCl, 5. 1% CH3COOH, 6. 3% CH3COOH, 7. 3% vapneni sumpor CaSx, 8. 1% ulje uljane repice, 9. 3% ulje uljane repice, 10. 3% suncokretovo ulje, 11. 3% sojino ulje, 12. 5% dekstrin, 13. emulgator 100 + OCA 30. Kemijski prorjeđivači primijenjeni su u fenološkom stadiju u vrhuncu cvjetanja. Najbolje prorjeđivanje plodova, slično onima s rukom, zabilježeno je pri nanošenju 3% ulja uljane repice. Prilikom ovog tretmana uočena je razmjerno jaka rđavost kože ploda. Statistički značajna manji broj plodova također se pojavilo kada je raspršeno 1,5% NaCl i 3% sojinog ulja, ali s manje izraženom rđavošću jabuka

Modern soil tillage trends in source protection regions

Vodoopskrbna područja (VOP) predstavljaju zaštitu izvora pitke vode (uključujući vodu iz jezera, rijeka i podzemnih vodonosnika) od prekomjerne uporabe i onečišćenja. U većini europskih zemalja VOP se sastoji od četiri osjetljiva područja; zona bunara (VOP0), zona crpljenja vode (VOPI), značajna površina za punjenje podzemnih voda (VOPII) i vrlo ranjivo područje (VOPIII). Budući da je VOP obično sastavni dio poljoprivrednog krajolika, poljoprivredna praksa može izravno utjecati na kvalitetu vode te se zbog toga vodoopskrbnim područjima obično regulira/ograničava način konvencionalne poljoprivrede, posebice obrade tla, gnojidbe i upotrebu pesticida. Iz tog razloga, u mnogim VOPI i VOPII zonama konzervacijska obrada (CT) predstavlja jedini način pripreme tla za sjetvu. U ovom radu prikazani su CT sustavi, koji uzrokuju minimalni mehanički poremećaj tla odnosno direktnu sjetvu, pokrivenost tla malčem i raznolikost ratarskih kultura. CT je globalno prihvaćena poljoprivredna praksa kojom se obrađuje oko 11% poljoprivrednog zemljišta na svim kontinentima.Source Protection Region (SPR) represents source water (including water from lakes, rivers and underground aquifers) protection from overuse and contamination. In majority of European countries SPR consists of four vulnerable areas; wellhead protection area (WHPA), intake protection zone (IPZ), significant gro- undwater recharge area (SGRA) and highly vulnerable area (HVA). Since SPR is usually the part of agricultural landscape the water quality might be affected by the agricultural practices, thus the Water Act usually regulate/limit the way of conventional farming, especially soil tillage, fertilization and pesticide application. For this reason, in many IPZ and SGRA zones the conservation tillage (CT) represents the only way of preparing the soil for sowing. CT systems, comprising no or minimum mechanical soil disturbance, organic mulch soil cover, and crop species diversification is presented in this paper. CT is globally adopted practice corresponding to about 11% of field cropland in all continents

Apple harvesting machines – current state and outlooks

Ručno branje jabuka pomoću vreća, košara i ljestvi skupo je i neučinkovito. Uvođenje platformi olakšava berbu s najviših grana i povećava radnu učinkovitost do 100 kg voća na sat. Još veća učinkovitost postiže se pravovremenim prorjeđivanjem plodova te uvođenjem platformi s gumiranim trakama i automatskim sustavom za punjenje standardnih boks paleta (\u27pluck-o-track\u27). Međutim, skupa radna snaga traži nova rješenja tj. upotrebu robota za berbu plodova. Prvi eksperimentalni robot pojavio se već 1998. godine, ali je za neometan rad tražio poseban Y uzgojni oblik jabuka koji je sprečavao daljnje uvođenje u praksu. Suvremeni ACRO robot može brati jabuke u komercijalnim voćnjacima pomoću vakuumske hvataljke i integrirane USB kamere. Zbog upotrebe jedne ruke roboti su još relativno spori pa se u budućnosti planira napraviti sustav s više neovisnih robotskih ruku.Apple hand picking by bags, baskets and ladders is expensive and inefficient. The introduction of the platform makes it easy to harvest from the highest branches and boosts productivity to 100 kg of fruit per hour. Even greater efficiency is achieved by correct thinning and introducing of platform with rubber bands and automatic filling system into standard boks pallet (so called \u27pluck-on-track\u27). However, expensive labour still force producers for seeking new solutions in the form of robots to harvest the fruit. The first experimental robot appeared already in 1998 but for the smooth operation special Y shape growing apple form was necessary which prevented further introduce to practice. Recently, a modern ACRO robot can pick apples in commercial orchards using vacuum gripper and integrated USB camera. Due to the use of one arm robots are still relatively slow, so in the future more independent robotic arms should be integrated in the system to make it more efficient

Effects of nozzle difference on droplet deposition in spraying of barley (Hordeum vulgare L.) at spike stage

U eksperimentalnom polju Sveučilišnog centra za poljoprivredu (UKC) Pohorski Dvor Fakulteta za kmetijstvo in biosistemske vede pokraj Maribora, u 2012. godini proučavan je utjecaj anti-drift mlaznica (Lechler ID 120-03, Albuz AVI TWIN 110-03 i 110-03 Turbo Drop HiSpeed) na depozit po horizontali i vertikali biljakaozimog ječma u usporedbi s depozitom standardne mlaznice (Lechler LU 120-03). Najveći normaliziran depozitpostignut je mlaznicom Turbo Drop HiSpeed 110-03 te 120-03 Lechler ID koji se statistički razlikuje od rezultata mlaznica Albuz AVI Twin 110-03 i Lechler LU 120-03. Kao što se očekivalo, najveći depozit izmjeren je u gornjoj trećini lišća. Iznenađujuće visoke su vrijednosti taloženja u donjoj trećini lišća i statistički se ne razlikuju od vrijednosti ugornjoj trećini. Najmanji su depoziti na stabljici i statistički se razlikuje od ostalih slojeva biljaka.U našem eksperimentu najbolje rezultate postigli smo asimetričnom Turbo HiSpeed mlaznicom.Na temelju rezultata otkrili smo da je mlaznica Turbo Drop HiSpeed najpogodnija za suzbijanje bolesti ječma u cvatnji, a i kasnije za zaštitu klasa od bolesti i štetnih organizama.Faculty of Agriculture and Life Sciences conducted in 2012 a study on the effects of anti-drift nozzles (Lechler ID 120-03, Albuz AVI TWIN 110-03 and 110-03 Turbo Drop HiSpeed) on the horizontal and vertical deposit in winter barley and a comparison with the deposit achieved by standard nozzles (Lechler LU 120-03) that took place at the University Agriculture Centre agricultural experiment station Phorski Dvor near Maribor. The largest normalized deposit was measured with Turbo Drop HiSpeed 110-03 and 120-03 Lechler ID nozzles and was statistically different from the results of Albuz AVI Twin 110-03 and Lechler LU 120-03 nozzles. As expected, the largest deposit was measured on upper leaves. Only minimal deposits that were statistically different from all other parts of the plant were detected on the stem. In our experiment, the best results were achieved using the asymmetric Turbo HiSpeed nozzle. Based on the results, we found that Turbo Drop HiSpeed nozzle is the most appropriate nozzle for the disease control of barley during bloom, and for the disease and pest protection in later stages of crop development

Possibility of increasing the efficiency of preparation of soil and sowing of winter cereals with elements of precision agriculture

Koncept precizne poljoprivrede vrlo je širok, a najčešće se pojašnjava povećanom učinkovitošću postignutom pomoću precizne navigacije, digitalnih karata i odgovarajućeg softvera. Različite studije širom svijeta pokazale su znatnu uštedu potrošnje goriva i vremena tijekom obrade i sjetve tla koja se temelji na izostavljanju preklapanja i učestalosti okretanja na kraju polja. Za manje farme, koje obično koriste trometarske radne strojeve (kultivator, gruber, valjari) smanjuje se potrebno radno vrijeme do 15,7 % i ušteda goriva do 8,66%, a na strojevima od šest metara do 12,6 % vremena i 8,28 % goriva. Glavni razlog je smanjenje širine preklapanja vožnje koja u uvjetima ručne vožnje obično predstavlja od 6,5 do 9,5 % nazivne radne širine. Korištenje preciznih poljoprivrednih tehnologija omogućuje također bolje planiranje i analizu radnih postupaka.The concept of precision farming is wide, and it is represented with the efficiency achieved with the help of precise RTK (Real Time Kinematic) navigation, digital maps and appropriate software. Different studies around the world reported considerable fuel and time saving during soil tillage and seeding which based on omitting the overlapping and the frequency of turning round at the end of fields. For smaller farms, which commonly use 3 m working machines (cultivator, chisels, disc harrow) up to 15.7% of the time and 8.66 % of the fuel can be saved, while on 6 m machines up to 12.6 % of the time and 8.28% of fuel is saved. The main reason lies in the reduction of overlapping width which in manual driving conditions usually represent about 10 % of nominal working width. The use of precision agriculture technologies allows us to better plan and analyze the working procedures

Comparison of different grape harvesters

U intenzivnom uzgoju vinove loze nužno je koristiti suvremenu mehanizaciju kako bi se svi poslovi obavili pravovremeno i kvalitetno uz najmanje moguće troškove. Kako ručna berba zahtijeva između 250 – 300 radnih sati ljudskog rada logično je tražiti smanjenje troškova proizvodnje uvođenjem kombajna za berbu. Usprkos početnim problemima s kvalitetom rada početkom 1970-ih godina, mehanizacija berbe grožđa postaje sve prisutnija u vinogradarskim regijama svijeta. Ekonomske prednosti, kontinuirani razvoj strojeva, i konačno međunarodna standardizacija ispitnih metoda za komparativnu procjenu metoda očitavanja, doveli su do svjetskog uspostavljanja mehaniziranog berbe grožđa. U nastavku su predstavljeni preduvjeti ove tehnologije, prednosti i nedostaci, vučenih i samohodnih strojevi kao i neke tehničke inovacije.The high workload in the grape harvest (250–300 hours) and the connected limited impact resulted in the first attempts with grape harvesters in the late seventies. Since then, in spite of initial quality problems, the mechanization of grape harvesting has become more and more prevalent in the wine-growing regions of the world. The economic advantages, the continuous development of the machines and finally also the international standardization of the test methods for the comparative assessment of the reading methods led to a worldwide establishment of mechanized grape harvesting. In the following, the prerequisites for this technology, the pros and cons, towed and self-propelled machines as well as some technical innovations are presented

Fertilization and soil supply in organic production of apples

Osnovu visoke produktivnosti ekoloških voćnjaka osim dobro izvedenih tehnoloških mjera predstavlja aktivan život u tlu na kojeg izravno utječemo izborom pravih meliorativnih biljnih vrsti, opskrbom ozelenjenih površina malčiranjem, okapanjem prostora ispod drveća te pravovremenim unosom organskih gnojiva u tlo. Budući da je u ekološkoj proizvodnji zabranjena upotreba herbicida, koristimo sjetvu korisnih pokrovnih biljki kao što su oštri žednjak (Sedum acre), podzemna djetelina (Trifolium subterraneum) ili runjika (Hieracium pilosella) koje su niskoga rasta i ne zahtijevaju puno vode za rast i razvoj, ali mogu spriječiti rast agresivnih korova kao što su čičak ili slak. U suvremenu tehniku za kontrolu korova ispod stabala ubrajaju se tri grupe strojeva: bočni malčeri, strojevi za okopavanje u redovima te strojevi za podrezivanje trave.Beside well-implemented technological measures, the basis for high productivity in ecological orchards represents an active life in the soil, which is influenced directly by seeding adaptive ameliorative plant species, regular mulching of driving trams, digging the belt under the trees and adding organic fertilizers into the soil in correct time. Since in the organic production the use of herbicides is prohibited, the seeding of sharp stonecrop (Sedum acre), underground Trifolium (T. subteraneum) or hawkweed (Hieracium pilosella) is recommended which are low in growth and do not require a lot of water for growth and development but can even inhibit the growth of aggressive weeds such as velcro or morning glory. The modern technique for controlling weeds in the tree belt includes three groups of machines; side mulchers, hoeing machines for tree belt and machines for trimming gras