Utjecaj tvrdoće podloge na otpornost abrazijskom trošenju triboloških prevlaka

The paper gives comparative analysis of properties of tribological coatings obtained by thermo chemical processes - classical vanadizing coating and vanadizing coating with prior carburization of the substrate, used as protection against abrasive wear. Properties of coating hardness, substrate hardness underneath the coating and abrasive wear resistance of the coating are compared. The comparative analysis proved justification for introduction of carburization of the substrate prior to vanadizing process because of abrasive wear resistance increase.U radu je prikazana usporedna analiza svojstava triboloških prevlaka dobivenih toplinsko-kemijskim postupcima - klasično vanadirana prevlaka i vanadirana prevlaka s prethodno naugljičenim supstratom, koje su primjenjene za zaštitu od abrazijskog trošenja. Uspoređivana su svojstva tvrdoće prevlake, tvrdoće supstrata ispod prevlake i otpornosti prevlake abrazijskom trošenju. Usporedna analiza potvrdila je opravdanost uvođenja naugljičenja supstrata prije postupka vanadiranja zbog povećanja otpornosti abrazijskom trošenju

Ferografija u službi održavanja po stanju

The model of maintenance is an algorithm of activities which aims at achieving the condition of a technical system that can ensure fulfilling the goals as well as predicting possible equipment breakdowns. Researches point out that corrective maintenance is associated with high cost and considerable time consumption. On the other side there are method of predictive maintenance, which presents a possibility to detect and predict a technical system failure and method of preventive maintenance, which performs the set tasks on technically correct systems in order to avoid failures. The paper accentuates and reviews the position and significance of the technology used for an early prediction of machinery wear by means of one out of a series of analyses of lubricant oils known as ferrography.Model održavanja jest algoritam aktivnosti koji ima za cilj dovođenje tehničkih sustava u stanje koje će omogućiti postizanje ciljeva, istovremeno predviđajući i mogućnost zastoja u proizvodnji. Istraživanja su dokazala kako korektivno održavanje ima za posljedicu visoke troškove i produženo vrijeme zastoja. Nasuprot ovim metodama postoji i prediktivno održavanje koje predstavlja mogućnost otkrivanja i predviđanja kvara tehničkog sustava te preventivno održavanje koje provodi zadane zadatke na tehnički ispravnim sustavima nužne za izbjegavanje kvara tehničkog sustava. U radu se izdvaja i daje pregled stanja i važnosti tehnologije koja služi za vrlo rano predviđanje stanja procesa trošenja tehničkog sustava i to uz pomoć jedne od niza analiza ulja za podmazivanje nazvane ferografija

A Comparison of Precise Fertilization Prescription Rates to a Conventional Approach Based on the Open Source GIS Software

Fertilization is one of the most important components of precision agriculture, ensuring high and stable crop yields. The process of spatial interpolation of soil sample data is recognized as a reliable method of determining the prescription rates for precise fertilization. However, the application of a free open-source geographic information system (GIS) software was often overlooked in the process. In this study, a method of precise fertilization prescription map creation was developed using an open-source GIS software to enable a wider and cheaper availability of its application. The study area covered three independent locations in Osijek-Baranja County. A method was developed for the fertilization of sugar beet with phosphorous pentoxide, but its application is universal with regard to the crop type. An ordinary kriging was determined as an optimal interpolation method for spatial interpolation, with the mean RMSE of 1.8754 and R2of 0.6955. By comparing the precision fertilization prescription rates to a conventional approach, the differences of 4.1 kg ha-1 for Location 1, 15.8 kg ha-1 for Location 2, and 11.2 kg ha-1 for Location 3 were observed. These values indicate a general deficit in soil phosphorous pentoxide, and precise fertilization could ensure its optimal content in the future sowing seasons

THE MODEL OF CREATING NOISE MAPS IN THE OPERATION OF TECHNICAL SYSTEMS FOR SHREDDING PLANT MASS BY THE POINT KRIGING METHOD

U radu su prikazane neke od mogućnosti primjene geostatističkih modela u području analize buke na radnom mjestu. Istraživanje je obavljeno u okruženju tehničkog sustava, sitnilice biljne mase „Willibald 2800“ i kombiniranog radnog stroja (traktorski utovarivač s dubinskom žlicom) proizvođača „JCB“ tipa „4CX“ koji je punio sitnilicu biljnom masom. Istraživanje je provedeno tijekom uobičajene eksploatacije strojeva. Mjerenje emitirane razine buke obavljeno je uređajem za mjerenje buke proizvođača „METREL“ tipa „Multinorm MI 6201 EU“ s pripadajućom zvučnom sondom (mikrofonom klase B) istog proizvođača. Krajnji je rezultat istraživanja model generiranja dvodimenzionalne i trodimenzionalne karte buke „Point Krigging“ metodom koja na svima razumljiv način prikazuje rezultate mjerenja buke i omogućava stručnjacima lakše donošenje odluka glede sigurnog rada. Karte buke su neophodne za adekvatno praćenje i monitoring štetnih utjecaja na čovjeka u radnom okruženju.The paper describes some of the possible applications of geostatistical models in the analysis of noise in the workplace. This study was conducted in an environment of technical system, the shredder of plant mass "Willibald 2800" and the combined processing machine (tractor loader shovel) manufactured by "JCB", type "4CX" which was filling the shredder with plant mass. The survey was conducted during the normal operation of machines. Measuring emitted noise levels was carried out with the device for measuring noise produced by "METREL" type "Multinorm MI 6201 EU" with a corresponding sound transducer (microphone Class B) of the same manufacturer. The final result of the research is a model of generating two-dimensional and three dimensional maps of noise "Point Krigging" method which in an easily understood manner presents the results of noise measuring and allows experts to help you make decisions regarding safe operation. Noise maps are essential for adequate observations and monitoring of harmful effects on humans in the working environment

Metodologija razvoja karata namjene zemljišta u GIS okruženju – upravljanje resursima

The purpose of this research was to determine the methodology of land capability evaluation with regard to an array of objective limiting factors when growing, for example, perennial crops. The methodology of relief parameterization was used in the method for calculating geomorphological parameters, and pedometric mapping methods were used to calculate pedological variables. Inventory of the actual condition of land cover was made based on sketches and maps that were gathered during field research. These sketches were then geo-referenced and overlapped with LANDSAT satellite images to determine the actual situation. The best locations for a particular type of perennial plantation were selected by using logic and spatial queries. Best locations (in this example for vineyards) were identified as an area overlap (areas with, according to the spatial plan, either valuable, especially valuable or other arable soils, southern relief exposition with the total annual incident light >1,208 KWh/m2, and the location where the relief slope is not higher than 12% and lower than 2%, or where elevation exceeds 110 m and soil acidity does not exceed 5.6 pH). The query resulted in a simple map. The map shows areas which are either suitable for viticulture (1) or not suitable for viticulture (0). Similar approach could be used also for thematic maps of different purposes, for example, urbanization maps, or mapping valuable sources of water, gas, thermal wells and other resources of special importance for the country. According to the results obtained in our example of finding the methodology for development of thematic maps in GIS environment, the total of 17,782 ha in the County area is suitable for viticulture. The best way of developing spatial plans for particular crops would be to develop maps of negative scores for all crops, and then to standardize these values to find the best possible crop for each location. Thematic GIS layers can be used as the foundation for loans, advice on what crop to choose, making decisions on land re-allocation and land use, reconstruction i.e. modified land use.Svrha ovog istraživanja bila je utvrditi metodologiju bonitiranja poljoprivrednog zemljišta s obzirom na niz objektivnih ograničavajućih čimbenika koji se povećavaju, na primjer, kod višegodišnjih kultura. Metodologija parametrizacije reljefa rabljena je za izračun geomorfoloških parametara, a pedometrijske metode kartiranja za izračun pedoloških varijabli. Stvarno stanje pokrova zemljišta inventarizirano je na temelju skica i planova koji su prikupljeni tijekom terenskog istraživanja. Te skice su zatim georeferencirane i preklopljene s LANDSAT satelitskim snimkama kako bi se odredilo stvarno stanje. Optimalne lokacije za pojedini tip trajnog nasada odabrane su primjenom logičkih prostornih upita. One su (u ovom primjeru za vinograde) identificirane kao područja preklapanja (lokacije gdje se prema prostornom planu nalaze ili vrijedna, osobito vrijedna tla ili ostala obradiva tla i južne ekspozicije reljefa s količinom ukupne godišnje upadne svijetlosti >1208 KWh/m2 i lokacije gdje nagib reljefa nije veći od 12% i manji od 2%, odnosno gdje nadmorska visina nije manja od 110 m i gdje tla nisu kiselija od 5.6 pH). Kao rezultat upita dobivena je jednostavna karta koja pokazuje područja koja su pogodna (1) ili nisu pogodna za vinogradarstvo (0). Sličan pristup može se koristiti i na tematskim kartama različite svrhe, na primjer, urbanističkim planovima, kartama izvora vode, plina, termalnih bunara i drugih resursa od posebnog značaja za državu. Prema dobivenim rezultatima u našem primjeru, za vinogradarstvo je pogodno ukupno 17.782 ha na području Županije. Optimalni način izrade prostornih planova za pojedine kulture bio bi izraditi karte negativnih bodova za sve kulture, a zatim standardizirati te vrijednosti kako bi za svaku lokaciju pronašli najbolju moguću kulturu. Tematski GIS slojevi mogu se rabiti kao osnova kreditiranja, savjeta o izboru kulture, donošenja odluka o preraspodjeli i korištenju, rekonstrukciji odnosno prenamjeni korištenja zemljišta

Određivanje pogodnosti poljoprivrednog zemljišta za uzgoj kukuruza (Zea mays L.) primjenom višerazinske GIS multikriterijske analize u kontinentalnoj Hrvatskoj

Previous research in continental Croatia indicated that cropland suitability levels are highly variable and existing natural resources could be better utilized. To overcome this issue, a method of multilevel Geographic information system (GIS)-based multicriteria analysis based on Analytic hierarchy process (AHP) for maize cropland suitability determination was proposed and evaluated. Free spatial data and free open-source software were implemented in the research in 250 m spatial resolution. The effects of air temperature, precipitation, soil and topography were modelled with the multilevel approach to avoid inconsistency in pairwise comparison due to criteria count. The maize suitability index (MSI) was calculated using the weighted linear combination, with higher values indicating proportionally higher suitability. According to the results of the AHP method, the weight consistency ratio was lower than the borderline value (0.042 < 0.100). Soil type and mean air temperature in June had the most impact on the suitability result, with 14.3% and 13.6% influence, respectively. The highest MSI values were achieved along the Sava River, especially in the proximity of Sisak and Nova Gradiška, resulting up to 3.9 of the possible 5.0. The sensitivity analysis of criteria indicated precipitation data in May, July and August particularly impactful in continental Croatia, while mean air temperature in September had very low variability of the suitability and was the least impactful on calculated MSI values.Prethodna istraživanja u kontinentalnoj Hrvatskoj pokazala su da su razine pogodnosti poljoprivrednog zemljišta vrlo promjenjive i da bi se postojeći prirodni resursi mogli iskoristiti na bolji način. Da bi se prevladalo ovo pitanje, predložena je i evaluirana metoda višerazinske GIS multikriterijske analize temeljena na analitičkom hijerarhijskom procesu (AHP) za utvrđivanje pogodnosti poljoprivrednog zemljišta za uzgoj kukuruza. Istraživanje je temeljeno na besplatnim prostornim podacima i besplatnom GIS softveru otvorenog koda s prostornom razlučivost od 250 m. Kriteriji temperature zraka, oborina, tla i topografije modelirani su višerazinskim pristupom kako bi se izbjegla nedosljednost u usporedbi parova kriterija. Indeks pogodnosti područja za uzgoj kukuruza (MSI) izračunat je primjenom težinske linearne kombinacije, pri čemu veće vrijednosti proporcionalno ukazuju na veću pogodnost. Prema rezultatima AHP metode, omjer konzistencije težina bio je niži od granične vrijednosti (0,042 <0,100). Vrsta tla i srednja temperatura zraka u lipnju najviše su utjecali na rezultat pogodnosti, s 14,3%, odnosno 13,6% utjecaja. Najveće MSI vrijednosti postignute su uz rijeku Savu, posebno u okolici Siska i Nove Gradiške, rezultirajući s 3,9 of mogućih 5,0. Analiza osjetljivosti kriterija ukazala je da su podaci o oborinama u svibnju, srpnju i kolovozu bili posebno utjecajni u kontinentalnoj Hrvatskoj, dok je srednja temperatura zraka u rujnu imala vrlo nisku varijabilnost pogodnosti i najmanje je utjecala na izračunate MSI vrijednosti

Sensors and Their Application in Precision Agriculture

The paper depicts sensors in precision agriculture. It encompasses the most significant and frequently used sensors in agriculture. Furthermore, the paper explains the main sensor types according to their design, the recorded range of electromagnetic spectrum, as well as the way of detection, recording, measuring, and representation of the detected energy. The development of remote research has provided deeper understanding of remote sensors and their advantages. The sensors installed on soil testing equipment, fertilizing and crop protection machinery, as well as crop picking machinery have been analyzed relative to precision farming. The paper depicts widely known sensors OptRx, ISARIA and VRT technology. The results of the paper assess the data collected by sensors and processed in order to produce maps for agrotechnical operations. The application of maps decreases the employment of human resources, heightens the capacity of data collection, increases the precision of agricultural activities, and finally results in decreasing the cost of final products. The technological progress over the past decade has enabled the development of technology with variable application standards (VRT) that, according to current needs, enables input optimization

Changing the mechanical properties of materials by forging of part of vehicle\u27s steering mechanism

Upravljački mehanizam jedan je od najvažnijih sustava na vozilima. S obzirom na njegovu važnost u pogledu cjelokupne sigurnosti vozila, posebna pozornost tijekom izrade dijelova mehanizma posvećuje se izboru materijala i odgovarajuće tehnologije. Određeni dijelovi upravljačkog mehanizma vozila izrađuju se tehnologijom kovanja u više tehnoloških faza. Karakteristični predstavnik takvih dijelova je krajnik spone. Prilikom kovanja u pojedinim fazama se mijenja mikrostruktura materijala, a time i mehaničkim svojstvima materijala izratka. Rad prikazuje navedene promjene na primjeru promjene tvrdoće, utvrđene mjerenjem na površini i u karakterističnom presjeku izratka.Steering mechanism is one of the most important systems on vehicles. Due to its importance in terms of overall vehicle safety, special attention is given to material selection and appropriate technology during the development of parts of the mechanism. Certain parts of the vehicle\u27s steering mechanism are made by forging technology in several technological phases. A typical representative of such parts is the track (tie) rod. During the forging in particular phases the microstructure of the material is changing, and thus the mechanical properties of materials of the workpiece. This paper presents these changes through the changes in hardness, determined by measuring on the surface and in typical cross-section of the workpiece

ANALIZA RGB I MULTISPEKTRALNE KAMERE NA BESPILOTNOME ZRAKOPLOVU ZA KLASIFIKACIJU KUKURUZA STROJNIM UČENJEM

This study investigated a crop and soil classification applying the Random Forest machine learning algorithm based on the red-green-blue (RGB) and multispectral sensor imaging deploying an unmanned aerial vehicle (UAV). The study area covered two 10 x 10 m subsets of a maize-sown agricultural parcel near Koška. The highest overall accuracy was obtained in the combination of the red edge (RE), near-infrared (NIR), and normalized difference vegetation index (NDVI) in both subsets, with a 99.8% and 91.8% overall accuracy, respectively. The conducted analysis proved that the RGB camera obtained sufficient accuracy and was an acceptable solution to the soil and vegetation classification. Additionally, a multispectral camera and spectral analysis allowed for a more detailed analysis, primarily of the spectrally similar areas. Thus, this procedure represents a basis for both the crop density calculation and weed detection while deploying an unmanned aerial vehicle. To ensure crop classification effectiveness in practical application, it is necessary to further integrate the weed classes in the current vegetation class and separate them into crop and weed classes.U ovoj studiji istražena je klasifikacija usjeva i tla korištenjem algoritma strojnoga učenja Random Forest, temeljenoga na crveno-zeleno-plavoj (RGB) i multispektralnoj kameri integriranoj na bespilotnome zrakoplovu. Područje istraživanja obuhvaćalo je dva podskupa poljoprivredne čestice kukuruza dimenzija 10 x 10 m u blizini Koške. Najveća ukupna točnost klasifikacije postignuta je u kombinaciji rubnoga crvenog (RE), bliskoga infracrvenog (NIR) kanala i indeksa normalizirane vegetacijske razlike (NDVI) u oba podskupa, s ukupnom točnošću od 99,8 %, odnosno 91,8 %. Provedena analiza pokazala je da je RGB kamera postigla dovoljnu točnost i da je prihvatljivo rješenje za klasifikaciju tla i vegetacije. Međutim, multispektralna kamera i spektralna analiza omogućile su detaljniju analizu, prvenstveno za spektralno slična područja. Ovaj je postupak temelj i za izračun gustoće usjeva i za otkrivanje korova s pomoću bespilotnih zrakoplova. Kako bi se osigurala učinkovitost klasifikacije usjeva u praktičnoj primjeni, potrebno je dodatno uključiti klase korova u trenutačnu klasu vegetacije i podijeliti ih na klase usjeva i korova