Partial Differential Equations for Cereal Seeds Distribution

During the recent years all crop species achieved the best possible field distribution so a high yield is to be expected. In this paper the solutions of two different diffusion equations are determined, which describe the optimal distribution of cereal grains over a field. Therefore, there are two different partial differential equations of cereal seed distribution-distinction is made between the longitudinal spacing (seeds in a row), and transverse distance (between two rows), as well as the sowing depth. In particular, closed forms of solutions are derived in each case. Although the result of the diffusion equation with respect to the distribution of the lateral seed distance of two adjacent rows is already known, a new solving method is presented in this paper. By this method, the partial differential equation is reduced to an ordinary one, which is easier to solve. In this paper it is shown that the distribution of lateral resp. longitudinal and in-depth wheat seed distances is achieved by a normal Gauss function resp. a log-normal function. Furthermore, it is demonstrated that the fitting functions of the best experimental results of wheat seeding distributions are particular solutions of the individual differential equations. Normal Gauss function describes lateral distribution with R2 = 0.9325; RSME = 1.2450, and log-normal function describes longitudinal distribution with R2 = 0.9380; RSME = 1.4696 as well as depth distribution with R2 = 0.9225; RSME = 2.0187

Razmak i dubina setve semena ozime raži

Proper seed distribution over area and depth is the essential condition that provides later uniform plants distribution over the vegetation space. Paper presents statistical analysis of two drills accuracy results in winter rye sowing. Experiment was done in north Kosovo, during rye sowing with two mechanical seed drills, OLT Gama and IMT 634.23. Besides the comparative analysis of the sowing results achieved by these two drills, in the paper is tested and verified the applicability of Gaussian function for analytical description of longitudinal, transverse and depth distribution of winter rye seed at the experimental plot.Pravilna raspodela semena po površini i dubini predstavlja osnovni uslov za obezbedjenje ravnomerne raspodele biljaka u vegetacionom prostoru. U radu je predstavljena statistička analiza rezultata ispitivanja tačnosti distribucije semena dve uskoredne sejalice u setvi ozime raži. Ispitivanja su izvedena na severu Kosova, u toku setve semena raži primenom dve sejalice Olt Gama 14 i IMT 634.23. Osim komparativne analize rezultata setve koji su dobijeni primenom ove dve sejalice, u radu je testirana i proverena primenljivost Gausove funkcije za analitičko opisivanje uzdužne, poprečne i raspodele semena ozime raži po dubini na eksperimentalnoj parceli

Mehanizovana berba peršuna u regionu Južnog Banata

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 konstrukcije, 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

Razmak i dubina setve semena ozime raži

Proper seed distribution over area and depth is the essential condition that provides later uniform plants distribution over the vegetation space. Paper presents statistical analysis of two drills accuracy results in winter rye sowing. Experiment was done in north Kosovo, during rye sowing with two mechanical seed drills, OLT Gama and IMT 634.23. Besides the comparative analysis of the sowing results achieved by these two drills, in the paper is tested and verified the applicability of Gaussian function for analytical description of longitudinal, transverse and depth distribution of winter rye seed at the experimental plot.Pravilna raspodela semena po površini i dubini predstavlja osnovni uslov za obezbedjenje ravnomerne raspodele biljaka u vegetacionom prostoru. U radu je predstavljena statistička analiza rezultata ispitivanja tačnosti distribucije semena dve uskoredne sejalice u setvi ozime raži. Ispitivanja su izvedena na severu Kosova, u toku setve semena raži primenom dve sejalice Olt Gama 14 i IMT 634.23. Osim komparativne analize rezultata setve koji su dobijeni primenom ove dve sejalice, u radu je testirana i proverena primenljivost Gausove funkcije za analitičko opisivanje uzdužne, poprečne i raspodele semena ozime raži po dubini na eksperimentalnoj parceli

Predviđanje kotrljanja čestice đubriva duž lopatice centrifugalnog rasipača sa diskom

The paper analyzes the motion of idealized spherical homogeneous fertilizer particle along the straight vane attached to flat rotating disc. The analysis, based on the assumption on the pure rolling of the particle along the vane (without sliding), has been performed in the non-inertial reference coordinate system, which rotates together with the spreader disk. The particle motion along the vane is described by hyperbolic cosine function, which is the solution of the ordinary in-homogenous secondorder differential equation having constant coefficients. Solution of this kind represents an approximation of the real motion of fertilizer particle along the radial vane fixed to horizontal disc rotating at constant angular velocity. However, it can be very useful for optimization of centrifugal spreader design and working parameters, as well as for further analysis of the whole fertilizer spreading process that also includes particle flight.U radu je analizirano kretanje idealizovane, loptaste, homogene čestice mineralnog đubriva duž radijalne lopatice postavljene na rotirajućem disku centrifugalnog rasipača đubriva. Analiza, zasnovana na pretpostavci o kotrljanju čestice duž lopatice bez klizanja, izvedena je u neinercijalnom referentnom koordinatnom sistemu koji rotira zajedno sa diskom za rasipanje đubriva. Kretanje čestice duž lopatice je opisano hiperboličnom kosinusnom funkcijom, koja predstavlja rešenje obične homogene diferencijalne jednačine drugog reda sa konstantnim koeficijentima, koja opisuje dinamiku čestice. Rešenje ove vrste predstavlja aproksimaciju stvarnog kretanja čestice đubriva duž lopatice diska koji rotira konstantnom ugaonom brzinom. Međutim, može biti veoma korisno za optimizaciju dizajna centrifugalnog raspršivača i njegovih radnih parametara, kao i za dalju analizu čitavog procesa rasipanja đubriva koji obuhvata i let čestice u vazduhu po napuštanju lopatice

The general movement assessment in non-European low- and middle-income countries

Abnormal general movements are among the most reliable markers for cerebral palsy. General movements are part of the spontaneous motor repertoire and are present from early fetal life until the end of the first half year after term. In addition to its high sensitivity (98%) and specificity (91%), the assessment of general movements is non-invasive and time- and cost-efficient. It is therefore ideal for assessing the integrity of the young nervous system, most notably in lowresource settings. Studies on the general movements assessment in low- and middle-income countries such as China, India, Iran, or South Africa are still rare but increasing. In Brazil, too, researchers have demonstrated that the evaluation of general movements adds to the functional assessment of the young nervous system. Applying general movements assessment in vulnerable populations in Brazil is therefore highly recommended

Mathematical Method for Droplet Size Distribution of Agricultural Nozzles

One of the technical factors from agricultural nozzles and overall plant protection is droplet diameter, which exclusively depends on working pressure, ISO number and nozzle type. Therefore, this paper was aimed to describe mathematical model for droplet size distribution. Through field exploitation experiment, data was used from three ISO numbers of nozzles (hollow cone 80 015; 02 and 03), two air-assisted sprayers (axial and radial fan) and two permanent crops (vineyard and an apple orchard). Water sensitive papers were used for evaluation of droplet diameters, and digital image analysis with Image J software was used for data processing. Mathematical model through homogenous diffusion equation and simplified differential equation shows that droplet size distribution had exponential function of modelling. Theoretical mathematical model was confirmed in experimental results, where coefficient of determination of exponential regression model for 80 015 nozzles was 0.93 with 5.15 of RMSE. The same coefficient for 80 02 nozzles was 0.96 with 2.88 of RMSE and for 80 03 nozzle R2 was 0.93 with 3.25 of RMSE. In addition, it is proved that droplet diameter depends on operating pressure with very high negative correlation (80 03 nozzles: r = −0.98; 80 02 nozzles: r = −0.97; 80 015 nozzles: r = −0.95). This data will help future researchers in their papers to facilitate and describe similar models for plat protection processes, and all agricultural producers to determine optimal operating pressure which is immensely important in economic, biologic, technical and ecologic aspect

Modelling the Compost Parameters During Mechanized Aerobic Fermentation

The article is focused on the behaviour of the basic properties of dairy cow's solid manure over the maturation period. The manure was exposed to mechanized aerobic processing by mechanically turning-over. Performed analysis comprehended measurements of mass participation percentages of organic components, mineral matters, H2O, N, P2O5 and K2O, as well as measurements of PH-values during the seven weeks of supervised test period of effective aerobic preparation of the composting material. Through maturation, large growth of averaged mass percentages of nitrogen, phosphorous-pentoxide and potassium-oxide, more than triple in comparison to the initial levels in a fresh solid, has been verified. Following a possible common approach in the scientific and technical practice, an analytical semi-empirical approach was used in describing the changes over the time of manure properties during composting, supported by prototype of the machine Kompomat 1. Combining the analytical theory of diffusion partial differential equations and application of numerical methods to non-linear fitting of the experimental output data, it was verified that all acquired manure parameters follow an identical general exponential law (R2 all properties = 0,906-0,990; RMSEall properties = 0,010-2,544). Clear relationships between the values of basic parameters of solid manure under mechanized aerobic fermentation (y) and composting duration lap time (x) have been established. © 2022, Strojarski Facultet. All rights reserved

One-dimensional diffusion equation for the particle size distribution of perlite filter granulation

Mnoštvo pročistačkih sustava do sada je načinjeno s uporabom različitih granulacija perlita. Raspodjela veličina čestica perlita izravno utječe na svojstva retencije pročistačkih medija. Informacije o raspodjeli veličine granulacija perlita, koji se koriste u svakom konkretnom postupku dead-end filtracije (filtracija koja se odvija u pravcu okomitom na ravninu pročistača), od presudne je važnosti za odgovarajuću tvorbu pročistaćkog medija. Kako bi se olakšala tvorba pročistaćkog medija koji posjeduje pročistaćke sposobnosti ove vrste, novi i specifični matematički model je razvijen za ovo istraživanje. Temelji se na odgovarajućoj parcijalnoj diferencijalnoj jednadžbi i dodanim matematičkim uvjetima, čije rješenje je eksponencijalna funkcija koja opisuje vjerojatnost raspodjele gustoće različitih veličina čestica perlita. Formulirani model eksperimentalno je potvrđen mjerenjem veličine čestica perlita pomoću morfometrijske metode, koja se temelji na primjeni standardnog svjetlosnog mikroskopa i softvera za digitalnu analizu slika. Postupak pronalaženja najtočnije funkcije za rezultate istraživanja ostvaruje zadovoljavajuću točnost - visoki R2 čimbenik (R2 = 0,905) i mala vrijednost srednje kvadratne pogreše (MSE = 0,490).Many filtration systems employing perlite granulations have been designed so far. Size distribution of perlite particles directly influences the retention properties of filter media. The information on the size distribution of perlite particles, used in each specific dead-end filtration process (the flow of fluid being filtered is perpendicular to the surface of filter medium), is crucial for the adequate design of filter medium. In order to facilitate the design of filter systems possessing filter media of this kind, a new and particular mathematical model has been developed for this present study. It is based on an appropriate partial differential equation and additional mathematical conditions, whose solution is an exponential function describing the probability density distribution of perlite particle sizes. The formulated model was experimentally verified by measuring the particle sizes of a perlite granulation using the morphometric method, based on the application of a standard light microscope and digital image analysis software. The fitting procedure of experimental data gave acceptable values of accuracy parameters - high R-square factor (R2 = 0,905) and small value of the root-mean square error (MSE = 0,490)