Savremeni pristupi upotrebe kukuruza

From a global standpoint, maize is one of the most important crops and as such one of the most significant naturally renewable carbohydrate raw materials of not only energy but also numerous very different products. The dominance and superiority of maize are primarily caused by and resulted from the extremely wide, very diversified and enormous possibilities of its utilization. Previous accomplishments were presented and prospective developments of the maize utilization were discussed in the present study. The recent utilizations of maize in the production of bioethanol biodegradable plastics and textile fibres were particularly emphasized and described. In addition, a brief review on changes in the global maize production was also presented.Posmatrano u svetskim razmerama kukuruz je je jedna od najznačajnijih gajenih biljaka i kao takav ujedno i jedna od najznačajnijih prirodno obnovljivih ugljenohidratnih sirovina energije i jako velikog broja veoma različitih proizvoda. Dominacija i superiorni položaj kukuruza uslovljeni su prevashodno izuzetno širokim, veoma raznovrsnim i ogromnim mogućnostima njegove upotrebe. U ovom radu su prikazana dosadašnja dostignuća i diskutovane perspektive budućeg razvoja upotrebe kukuruza. Posebno su istaknute i opisane najnovije upotrebe kukuruza u proizvodnji bioetanola, biorazgradive plastike i tekstilnih vlakana. Pored toga, dat je i kratak osvrt na promene u svetskoj proizvodnji kukuruza

Genetic variability as background for the achievements and prospects of the maize utilisation development

Maize is one of the most important crops, and as such, one of the most significant naturally renewable carbohydrate raw materials of energy and numerous very different products. The dominance and superiority of maize are primarily caused by the extremely wide, very diversified and enormous possibilities of its utilisation. Previous accomplishments are presented and prospective developments of the maize chemistry and technology, i.e. maize utilisation in our country and worldwide were discussed in the present study. The objective of this study was to advert to this section of science that is full of real and great challenges. Changes in the maize production and utilisation are described. Some very important questions were asked, such as: what is it that makes maize such a valuable, naturally renewable raw material, how and why do we sow maize and harvest energy and products?

Technological conditions of flight instrument development

Razvoj avijacije postavio je tehnološke zahteve koji su uslovili nastanak i neprekidan razvoj instrumentalizacije leta. Praktična primena avijacije u vojne i civilne svrhe, razvoj vazdušnog saobraćaja i tehnike uopšte, povećavaju brzine, visine i dužine preleta, dok letelice postaju sve veće i složenije. Od lakih drvenih konstrukcija sa otvorenom pilotskom kabinom, danas avioni po svim vremenskim uslovima prelaze velike razdaljine što pilota i konstrukciju letelica dovodi granica izdržljivosti. Na početku, tokom pionirskog perioda, letenje je bilo u potpunosti u rukama pilota i sve odluke je donosio na osnovu svog iskustva i psihofizičkih sposobnosti. Sa povećanjem složenosti letelica i dužine preleta, sve veći uticaj na tehniku pilotiranja imaju tehnološki, ergonomski i bezbednosni uslovi. Ovaj rad se osvrće na tehnološke uslove i razvoj sistema instrumentalizacije i automatizacije leta. Primena digitalne pilotske kabine uspostavlja mnoge pozitivne standarde ali i postavlja pitanja daljeg pravca razvoja vazduhoplovstva. Poseban prikaz opisuje upotrebu i razvoj jednog od osnovnih instrumenata u pilotskoj kabini – kompasa. Ovaj instrument se i dalje, u skoro nepromenjenom obliku, nalazi u modernom digitalnom kokpitu – glass cockpit-u.The development of aviation has set technological requirements that have conditioned the emergence and development of flight instrumentalization. The practical application of aviation for military and civilian purposes, the development of air traffic and technology in general, increase speeds, altitudes and flight lengths, while aircraft are becoming larger and more complex. From light wooden constructions and open cockpit, today planes fly long distances in all weather conditions, which brought the pilot and the construction of the aircraft to the endurance limit. At the beginning, during the pioneer period, flying was completely in the hands of the pilot and he made all the decisions based on his experience and psychophysical abilities. With the complexity of aircraft and flying, technological, ergonomic and safety conditions have an increasing influence on piloting technique. This paper describes the technological conditions and the development of instrumentation and flight automation systems. The application of the digital cockpit establishes many positive standards, but also raises questions about the further direction of aviation development. A special review describes the use and development of one of the basic instruments in the cockpit -the compass. This instrument is still, in an almost unchanged form, in the modern digital cockpit -glass cockpit

Physical and chemical properties of various corn genotypes as a criterion of technological quality

Physical properties, such as test weight, 1000-kernel weight, kernel density flotation index, water absorption index and kernel hardness and chemical properties: protein, starch and oil contents, of twenty the most widely grown ZP corn hybrids of different genetic background and utilization purposes were studied. The results showed wide ranges of chemical and physical properties among the selected corn hybrids. Protein, starch and oil contents ranged from 8.9 to 13.5%, 67.5 to 73.7%, and 4.1 to 6.5%, respectively. The test weight was within the range of 771.8-897.7 kg m-3, while the 1000-kernel weight ranged from 121.6 to 392.7 g. The kernel density, i.e. flotation index was within the range of 1.23-1.34 g cm-3, i.e. 0-71 %, respectively, while the water absorption index ranged from 0.155 to 0.278. Kernel hardness, expressed as a milling response, and a hard fraction portion varied in the tested samples from 9.4 to 19.9s and 49.6 to 75.2%, respectively. The correlation analysis points to a very great interdependence among certain physical and chemical properties. Obtained high correlation coefficients could be used to predict not so easily measurable parameters based on the known value of the corresponding easily measurable parameter. A wide scope of tested quality parameters offers many possibilities in selection and estimation of hybrids for certain purposes

Fizičko-hemijske karakterisrike i hemijski sastav frakcije kukuruznog oklaska

Morphological structure and chemical composition of basic fractions - hard and soft -of maize cob are presented in this paper. Different chemical compositions and physical and chemical properties of these fractions, first of all, their great capability to bind fluid, especially oil and water define their use as an agent for degreasing and drying. A great hardness and abrasive capability of products produced by cob milling have put them to a use for polishing in metalworking industry, while the content of certain compounds (pentosan) is of a very great importance in chemical industry in the manufacturing of furfural and its derivates. Due to their inertness neutral pH values and lack of heavy metals, these products are used as organic carriers in the production of pesticides and agrochemicals, as well as, in cosmetics and pharmacy.U radu su date fizičko-hemijske karakteristike i hemijski sastav frakcija kukuruznog oklaska dobijenih po originalnoj ZP tehnologiji. Različit hemijski sastav i fizičko-hemijske karakteristike ovih frakcije - celgran A B, C, pre svega visoka sposobnost vezivanja tečnosti, naročito ulja i vode opredeljuju njihovu upotrebu kao medijuma za odmašćivanje i sušenje. Velika tvrdoća i abrazivna sposobnost proizvoda dobijenih mlevenjem oklaska našla je primenu za poliranje u metaloprerađivačkoj industriji, a sadržaj nekih jedinjenja od posebnog je značaja u hemijskoj industriji. Zbog svoje inertnosti, neutralne pH vrednosti i odsustva teških metala ovi proizvodi nalaze primenu kao organski nosači u proizvodnji pesticida i agrohemikalija kao i u kozmetici i farmaciji

Determination of the ductile-to-brittle transition temperature of NIOMOL 490 K steel welded joints

This paper is dedicated to the ductile–brittle transition behaviour of the microalloyed structural steel NIOMOL 490 K. This steel grade is used for welded pressure vessels subjected to dynamic loads and operating at sub-zero temperatures. Therefore, it must have an acceptable toughness. Due to its importance for the safety assessment of pressure vessels, a characterization of this steel was carried out using the Charpy V-notch impact test in the temperature range between - 60 ◦C and + 60 ◦C. The notches were located in parent material, heat affected zone and weld metal. In this paper, the tensile strength properties at ambient temperature and the nil ductility temperature in the temperature range from - 60 ◦C to + 60 ◦C are presented

Influence of Raster Angle on Tensile Properties of FDM Additively Manufactured Plates made from Carbon Reinforced PET-G Material

Tensile properties of thin plate specimens made from short carbon fiber reinforced PET-G material are experimentally evaluated for various raster angles (printing directions). In additive manufacturing (AM), raster angle is recognized as one of the key printing parameters which strongly influences the strength and stiffness of the final part. The relatively high average value of ultimate tensile strength was obtained for specimens printed with the 0° raster angle, compared to the value obtained for specimens printed with the 90° raster angle - 52.2 MPa and 25.4 MPa, respectively. Similarly, noticeably higher average value of modulus of elasticity was obtained for specimens printed with the 0° raster angle, compared to the value obtained for specimens printed with the 90° raster angle - 4752 MPa and 1569 MPa, respectively. Scanning electron microscopy (SEM) was used for analysis of specimens’ fracture surfaces. SEM images revealed considerable volume fraction of voids (porosity). Тhe porosity, together with weak bonding between two adjacent rasters, could be one of key factors for poor tensile properties of samples printed with rasters perpendicular to direction of load application (90° raster angle

Savremene metode određivanja kvaliteta i tehnološke vrednosti kukuruza

An ever growing importance of contemporary maize processing has imposed a need for more intensive research, within a field of quality and technological value of grain, as well as, relations between quality factors and maize utilization. A new concept of the developed maize market encompasses the identification of the most important utilization, as well as, requirements of each single use pertaining the essential grain properties. Several methods and tests for determination of properties, such as kernel hardness, kernel density, floatation index and water absorption index that are very important for estimation of the maize utilizable value, have been modified, according to contemporary tendencies in the world research, in the course of the long-term maize quality testing performed at the Department of technological research of the Maize Research Institute Zemun Polje.Rastući značaj suvremenih procesa prerade kukuruza nametnuo je potrebu intenziviranja istraživanja u oblasti kvaliteta i tehnološke urednosti zrna, kao i veze između faktora kvaliteta i upotrebe kukuruza. Novi koncept razvijenog tržišta kukuruza je da se identifikuju najznačajnije upotrebe, kao i zahtevi svake pojedinačne upotrebe u pogledu najbitnijih svojstava zrna. Sledeći tendencije savremenih svetskih istraživanja u višegodišnjim ispitivanjima kvaliteta kukuruza u Odseku za tehnološka istraživanja Instituta za kukuruz modifikovano je više metoda i testova za određivanje svojstava, kao što su tvrdoća zrna, gustina, indeks flotacije i indeks apsorpcije vode, koja su od izuzetnog značaja za procenu upotrebne urednosti kukuruza

Magnetic and mechanical characteristics of nickel-based superalloy after laser induced deformation

Nickel-based superalloys are used in load-bearing structures at elevated temperature and pressure and in harsh environment. Nickel based superalloys have good mechanical properties, good oxidation and corrosion resistance. Among the most demanding applications for a structural material are those in the turbine engines, in first place for turbine blades. Nickel based superalloys consist of nickel solid solution, strengthening ϒ’ phase (Ni3Al) and carbides. At room temperature turbine blades are paramagnetic. The earlier studies reported increase in magnetic properties of Ni3Al after induced deformation. In this paper, the magnetic properties of nickel based superalloy after deformation induced by laser waves are investigated and discussed. Mechanical characteristics are analyzed with regards to changes of magnetics properties

Antibacterial activity of chlorhexidine

Čiščenje in razkuževanje sta pomembna tekom celotne proizvodno-prodajne živilske verige. Z ustrezno metodo čiščenja in izborom razkužila lahko učinkovito preprečujemo kontaminacijo živil z nezaželenimi mikroorganizmi. V okviru diplomskega dela smo določili protibakterijsko delovanje klorheksidin diacetata. Aktivnost smo ovrednotili z določitvijo minimalne inhibitorne koncentracije (MIC) klorheksidin diacetata z bakterijami vrst Listeria monocytogenes (kot grampozitivne bakterije), Staphylococcus aureus (kot toksigene bakterije), Bacillus cereus (kot sporogene bakterije), Escherichia coli in Salmonella enterica (kot gramnegativne bakterije). MIC smo določili z metodo razredčevanja v mikrotitrski ploščici, kjer smo po dodatku reagenta INT (2-p-iodofenil-3-p-nitrofenil-5-fentil tetrazolijev klorid) določili metabolno aktivne bakterije. Število preživelih bakterij smo nato določili še z metodo štetja kolonij na trdem gojišču. Najbolj učinkovito je razkužilo delovalo na grampozitivne bakterije vrst Staph. aureus in L. monocytogenes, kjer je povprečna MIC znašala 0,9±0,3 mg/l. Povprečna MIC pri gramnegativnih bakterijah vrste E. coli je bila 1,1±0,3 mg/l in pri bakterijah vrste S. enterica 8,7±2,5 mg/l. Sporogene bakterije vrste B. cereus so imele MIC pri 1,5±0,6 mg/l. Hipotezo, da so gramnegativne bakterije vrst E. coli in S. enterica bolj odporne proti klorheksidin diacetatu kot grampozitivne bakterije vrst Staph. aureus, B. cereus in L. monocytogenes lahko potrdimo, čeprav bi za podrobnejše rezultate rabili večji obseg raziskovalnega dela. Sporogene grampozitivne bakterije vrste B. cereus so bolj odporne proti razkužilu kot nesporogene grampozitivne bakterije. Uporaba ustreznih koncentracij razkužila klorheksidina zmanjša prisotnost bakterij.Cleaning and disinfection have big importance through the production, manufacturing and distribution of food. With proper cleaning method and selection of disinfectants we can effectively prevent contamination of foods with unwanted microorganisms. Within the diploma work we investigated antibacterial activity of chlorhexidine diacetate. The activity was evaluated by determining minimum inhibitory concentration (MIC) for different bacteria, as follows, Listeria monocytogenes (as gram-positive bacterium), Staphylococcus aureus (as toxigenic bacterium), Bacillus cereus (as sporogenic bacterium), Escherichia coli and Salmonella enterica (as gram-negative bacteria). MIC was determined by micro-dilution method after adding INT reagent (2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-tetrazolium chloride) that dyed metabolic active bacterial cells. The number of surviving bacteria was also determined with the plate count method. Chlorhexidine diacetate was the most efficient for gram-positive Staph. aureus and L. monocytogenes stains, where the MIC was 0.9±0.3 mg/l. The gram-negative E. coli strain had MIC of 1.1±0.3 mg/l. The gram-negative S. enterica strain had the highest MIC of 8.7±2.5 mg/l. Sporogenic B. cereus had MIC of 1.5±0.6 mg/l. The hypothesis that gram-negative bacteria such as E. coli and S. enterica are more resistant to chlorhexidine diacetate than gram-positive bacteria such as Staph. aureus, B. cereus and L. monocytogenes was confirmed. Sporogenic bacteria like B. cereus were more resistant than non-sporogenic gram-positive bacteria. Usage of appropriate concentrations of chlorhexidine decrease the presence of bacteria