39 research outputs found
Potencijal otpadne vode mljekarske industrije za proces denitrifikacije
In this work the potential of dairy wastewater for denitrification process by means of a microbial culture of nitrificants and denitrificants was investigated. The aim of this work was to remove nitrate by using organic compounds from the dairy wastewater as an electron donors. The minimal ratio of COD/NO3-N of 10 (COD-chemical oxygen demand/NO3-N-nitrate nitrogen) was required to achieve complete reduction of NO3-N. The microbial culture of nitrificants and denitrificants, that was previously adapted on the dairy wastewater, carried out nitrate reduction with a different substrate utilization rate. The denitrification rate of 5.75 mg NO3-N/Lh was achieved at the beginning of denitrification when the microbial culture utilizes readily biodegradable COD. Further degradation occurred with the denitrification rate of 1.7 mg NO3-N/Lh.U ovom radu istražen je potencijal otpadne vode mljekarske industrije za proces denitrifikacije pomoÄu mikrobne kulture nitrifikanata i denitrifikanata. Cilj rada je bio ukloniti nitrat koristeÄi organske sastojke iz otpadne vode industrije prerade mlijeka kao elektron donore. Minimalan omjer KPK/ NO3-N (KPK-kemijska potroÅ”nja kisika/NO3-N-nitratni duÅ”ik) potreban za postizanje potpune redukcije NO3-N iznosi 10. Mikrobna kultura nitrifikanata i denitrifikanata, prethodno prilagoÄena na otpadnu vodu mljekarske industrije, provodi redukciju nitrata uz razliÄitu brzinu iskoriÅ”tenja supstrata. U poÄetku denitrifikacije mikrobna kultura troÅ”i lako razgradivi KPK i postiže brzinu denitrifikacije od 5,75 mg NO3-N/Lh. Daljnja razgradnja zbiva se uz brzinu denitrifikacije od 1,7 mg NO3 N/Lh
Potencijal otpadne vode mljekarske industrije za proces denitrifikacije
In this work the potential of dairy wastewater for denitrification process by means of a microbial culture of nitrificants and denitrificants was investigated. The aim of this work was to remove nitrate by using organic compounds from the dairy wastewater as an electron donors. The minimal ratio of COD/NO3-N of 10 (COD-chemical oxygen demand/NO3-N-nitrate nitrogen) was required to achieve complete reduction of NO3-N. The microbial culture of nitrificants and denitrificants, that was previously adapted on the dairy wastewater, carried out nitrate reduction with a different substrate utilization rate. The denitrification rate of 5.75 mg NO3-N/Lh was achieved at the beginning of denitrification when the microbial culture utilizes readily biodegradable COD. Further degradation occurred with the denitrification rate of 1.7 mg NO3-N/Lh.U ovom radu istražen je potencijal otpadne vode mljekarske industrije za proces denitrifikacije pomoÄu mikrobne kulture nitrifikanata i denitrifikanata. Cilj rada je bio ukloniti nitrat koristeÄi organske sastojke iz otpadne vode industrije prerade mlijeka kao elektron donore. Minimalan omjer KPK/ NO3-N (KPK-kemijska potroÅ”nja kisika/NO3-N-nitratni duÅ”ik) potreban za postizanje potpune redukcije NO3-N iznosi 10. Mikrobna kultura nitrifikanata i denitrifikanata, prethodno prilagoÄena na otpadnu vodu mljekarske industrije, provodi redukciju nitrata uz razliÄitu brzinu iskoriÅ”tenja supstrata. U poÄetku denitrifikacije mikrobna kultura troÅ”i lako razgradivi KPK i postiže brzinu denitrifikacije od 5,75 mg NO3-N/Lh. Daljnja razgradnja zbiva se uz brzinu denitrifikacije od 1,7 mg NO3 N/Lh
DEVELOPMENT OF A DIDACTIC SET OF PNEUMATICS AND SERVO PNEUMATICS IN ENGINEERING EDUCATION
Control of the work piece position is one of the most difficult and most common problems in manufacturing. This problem is in most cases solved by using an electric axis with a servo or step motor, servo pneumatic or classical pneumatic components. Having this in mind, a didactic set for controlling the work piece position in vertical tubes has been developed and will be described in this paper. This system has been realized by using servo pneumatics and classical pneumatics. In this system, feedback was used for controlling the work piece position in a servo pneumatic system. The feedback was obtained by using a photoelectric sensor. The developed system is a part of the laboratory equipment used by undergraduate and graduate students in the Industrial Engineering and Mechatronics study programme at the Faculty of Technical Sciences, University of Novi Sad, as well as by individuals who already work in industry. This didactic set encourages active participation of students in class and helps them with their tasks, which include learning about the structure of the set and the way of controlling the work piece position
Novi nalazi crne voline Dipturus nidarosiensis (Storm, 1881) (Pisces: Rajidae) iz Jadranskoga mora
Additional records of the Norwegian skate Dipturus nidarosiensis (Storm, 1881)from the Adri-atic Sea are reported. Two specimens were collected in the southern Adriatic Pit in 2008 and 2010, respectively. The records reported herein improve our knowledge on the distribution of a rarely encountered, deep water species D. nidarosiensis, whose presence has only recently been confirmed in the Mediterranean Sea.U radu su opisani novi nalazi crne voline Dipturus nidarosiensis (Storm, 1881) iz Jadran-skoga mora. Dva primjerka ulovljena su na podruÄju Južnojadranske kotline 2008. odnosno 2010. godine. Ovi nalazi proÅ”iruju saznanja o distribuciji ove rijetke dubokomorske vrste Äija je prisutnost u Sredozemnom moru tek nedavno utvrÄena
Integrisana primena plodoreda i herbicida za kontrolu korova u kukuruzu
Research on nonherbicidal weed management strategies that integrate other weed management systems with herbicide use are still actual. Crop rotation is important measure within IWMS, aimed to successful maize production and pest control. Sequences with row and grain crops, legumes and cereals allow application of herbicides with different mode of action which directly infl uences weed abundance. Sequence composition is important as much as number and type of crop because of applied measures and their carry over effects. Effects of maize monoculture and three crop rotation maize-wheat-soybean and maize-soybean-wheat, integrated with herbicide application at recommended and low rates on annual and broadleaf maize weed control, were studied. The best effects on maize weed control showed MSW rotation, especially with the application of the recommended rate of herbicides. In this production system, biomasses of the annual and perennial weeds were significantly lower after one cycle of rotation, in all herbicide treatments. Cereal crop such as wheat together with herbicides used for its production, is much better preceding crop for maize weed control than soybean.ProuÄavanja nehemijskih mera za kontrolu korova, kao i njihove integrisane primene sa herbicidima u okviru integrisanog sistema mera za kontrolu korova (Integrated Weed Management System - IWMS), su i dalje veoma aktuelna. Plodored je važna mera za uspeÅ”no gajenje useva uz istovremenu kontrolu korova i drugih Å”tetnih organizama. Smena Å”irokoredih useva i strnina, leguminoza i žita omoguÄava primenu herbicida sa razliÄitim mehanizmima delovanja Äime se direktno utiÄe na zastupljenost korova. Osim broja i vrste useva koje ulaze u sastav plodoreda, veoma je važan i njihov redosled u rotaciji, jer Äe mere koje se primenjuju u prethodnom usevu imati efekat i na naredne useve. U ogledu je prouÄavan uticaj monokulture i dva tropoljna plodoreda kukuruz- pÅ”enica-soja i kukuruz-soja-pÅ”enica uz primenu herbicida, na zastupljenost jednogodiÅ”njih i viÅ”egodiÅ”njih korova u kukuruzu. U pogledu kontrole zakorovljenosti, najbolji efekat je ispoljio tropoljni plodored kukuruz-soja-pÅ”enica, posebno uz primenu herbicida u preporuÄenoj koliÄini. Nakon jedne rotacije useva, biomasa jednogodiÅ”njih, a naroÄito viÅ”egodiÅ”njih korova je znaÄajno smanjena u svim varijantama primene herbicida. PÅ”enica je, u pogledu kontrole korova, kao gusti usev, uz herbicide koji se primenjuju tokom njenog gajenja, pogodnija kao predusev za kukuruz u odnosu na soju
Common millet and soybean intercropping with bio-fertilizer as sustainable practice for managing grain yield and quality
Climate changes are one of the biggest threats to food security. Sustainable agriculture, focused on eco-friendly practices for highly efficient food production, enables greater resilience and safety. This study experimented on intercropping and bio-fertilizer application as convenient ecological solutions for crop yield stability and quality. The experiment was conducted during 2018 and 2020 with soybean and common millet sown in three sowing patterns: alternating rows, alternating strips 1 (2 rows of soybean + 2 rows of millet), and alternating strips 2 (2 rows of soybean + 4 rows of millet), as well as sole crops (control), with or without a bio-fertilizer Coveron. Grain yield and nutrient grain yield response were calculated through land equivalent ratio (LER) and element-LER (E-LER), while quality was estimated based on the concentration of antioxidants (phytate phosphorus, total phenolic compounds, and yellow pigment) and elements in grains, including potential bio-availability of essential elements. Results revealed LER values to be >1 for all sowing patterns, with the highest one achieved in alternating strips 1 (1.38) together with a greater level of all antioxidants in millet grain. Intercropping significantly enhanced Fe and Mn accumulation in both crops and simultaneously decreased the concentration of potentially toxic elements (Al, Cr) in millet grain. Potential bio-availability of essential elements, expressed through the ratio between phytic acid and Ca, Mg, Fe, and Zn revealed smaller values in intercropped soybean and millet with the bio-fertilizer. The bio-fertilizer also increased the concentration of some micro-elements in millet grain, classifying it as a highly dependent plant to microbial inoculation. Interaction of intercropping and bio-fertilizer was most pronounced for LER, E-LER, and accumulation of Fe and Mn in grains. These results highlighted the benefits of soybeanācommon millet intercropping, especially in combination with the bio-fertilizer, in light of enhanced land utilization and nutrient absorption, thus increasing the resilience of soybean and millet under dry land conditions and low-input systems toward stability and food security
21st Century engineering challenges observed through computer vision syndrome
Inženjerski posao poÄetkom novog tisuÄljeÄa viÅ”e se ne može zamisliti bez raÄunala. Inženjeri koji u svom radu koriste raÄunala ili neke druge ekrane za promatranje, kako za projektiranje, tako i u fazama rada u proizvodnji, izloženi su utjecaju sindroma raÄunalnog oka. U ovom radu definiran je sindrom raÄunalnog oka, objaÅ”njen je njegov nastanak i izložene su njegove posljedice. U srediÅ”njem dijelu rada dani su rezultati istraživanja provedenog u Republici Srbiji o pitanju poznavanja korisnika raÄunala, uoÄenim simptomima ovog sindroma i postojanju sindroma raÄunalnog oka. Na kraju rada izložena su rjeÅ”enja za smanjenje i sprjeÄavanje nastanka promatranog sindroma.In the beginning of the new millennium, professional engineering cannot be imagined exclusive of the use of computers. Engineers who use computers or some other monitoring display terminals, both in design and various manufacturing phases, have been exposed to the effects of computer vision syndrome. Computer has become almost an indispensable piece of equipment both in the office and at home. This paper defines the computer vision syndrome, describes its genesis and explains related consequences. In the central part of this paper, results are presented of the research conducted in the Republic of Serbia regarding computer users, detected computer vision syndrome symptoms as well as the genuine actuality of computer vision syndrome among computer users. The final part of the paper offers possible solutions for reducing the effects and preventing occurrence of the observed syndrome
ZnaÄaj sistema integrisanih mera za kontrolu korova u kukuruzu
Continual application of the same measures in the agricultural practice leads to the disturbances in connexions in agro-ecosystem. For the reason of damaging effects of herbicides, the combined application of the several measures for weed control, as a part of Integrated Weed Management System - IWMS is applying in the world and in our country in recent time. The concept of this system is development of the programs for weed control owing to combined or integrated application of preventive, direct, mechanical, chemical, biological and other measures. According to the presence of great number of weed species in maize crop, which have different life cycles and surviving types, it is unreal to expect that application of one measure solely could have satisfactory effect in weed control and lowering of potential weediness through the lowering of seed reserve and vegetative organs of weed plants in soil. The effect of application of the chosen measures system must not be short-lived, but it has to show results during the longer period. Moreover, it isnāt literal weed eradication, but reduction of the weed number to the level which could be tolerated by the crop, without threatening of the yield and radical disturbing of the balance in agro-ecosystem. Bearing all that in mind, the effects of combined application of the different measures of IWMS (crop rotation, tillage, fertilization, genotype choice, herbicide application) in maize weed control were analysed.Stalna primena istih mera u poljoprivredi vremenom dovodi do naruÅ”avanja odnosa u agroekosistemu. Radi smanjenja Å”tetnog delovanja herbicida, u svetu i kod nas se poslednjih godina sve viÅ”e preporuÄuje kombinovana primena viÅ”e mera za kontrolu korova u okviru sistema integrisanih mera (Integrated Weed Management System IWMS). Koncept ovog sistema je razvoj programa za kontrolu korova putem kombinovane ili integrisane primene preventivnih, direktnih, mehaniÄkih, hemijskih, bioloÅ”kih i drugih mera. S obzirom da se u usevu kukuruza javlja veliki broj vrsta korova sa razliÄitim životnim ciklusima i naÄinima preživljavanja, nerealno je oÄekivati da primena bilo koje mere pojedinaÄno može imati zadovoljavajuÄi efekat u kontroli korova i smanjenju potencijalne zakorovljenosti kroz smanjenje rezervi semena i vegetativnih organa korovskih biljaka u zemljiÅ”tu. Efekat primene odabranog sistema mera ne sme biti samo trenutan, naprotiv, mora da ima rezultate i na duži vremenski period. Isto tako, ne radi se o bukvalnom uniÅ”tavanju, tj. iskorenjivanju korova, veÄ o svoÄenju njihove brojnosti na nivo koji usev može da toleriÅ”e tako da prinos nije ugrožen a ravnoteža u agrosistemu nije radikalno naruÅ”ena. ImajuÄi sve navedeno u vidu, analizirani su efekti kombinovane primene razliÄitih mera iz sistema integrisanih mera (plodored, obrada, Äubrenje, gustina gajenja, izbor genotipa, primena herbicida) u kontroli korova u kukuruzu
MoguÄnosti primene sulfonilurea i triketonskih herbicida u usevu samooplodnih linija kukuruza
Herbicide efficacy is one of the most important herbicide properties. In addition to efficacy, the herbicide should possess certain selectivity for the crops. If there is not selectivity, it is possible to damage the plants after herbicide application, which can lead to loss of yield. The growing technology of broad row crops, such as maize, involves the application of herbicides as a measure of weed control. The aim of this study was to examine the selectivity of sulfonylurea and triketons herbicides applied in five lines, following visual plant changes (EWRC) and grain yield. Herbicides were applied at recommended doses for the production of hybrid maize, as well as in double doses. The applied triketons (mesotrione and topramezone) did not cause significant damage to the lines tested, unlike sulfonylureas (rimsulfuron and foramsulfuron). Sulfonylureas significantly influence of grain yield, the highest in early maturity group lines. Triketons had no effect on grain yield of maize lines examined.Efikasnost prema korovima je jedna od najbitnijih osobina herbicida. Pored efikasnosti, herbicid bi trebalo da poseduje i odgovarajuÄu selektivnost prema usevu u kome se primenjuje. Ukoliko se selektivnost herbicida nedovoljno poznaje moguÄe je da doÄe do oÅ”teÄenja useva posle primene, Å”to može dovesti i do gubitka prinosa. Tehnologija gajenja Å”irokorednih useva, kakav je kukuruz, podrazumeva primenu herbicida, kao meru suzbijanja korova. Cilj ovog rada je bio da se ispita selektivnost sulfonilurea i triketonskih herbicida u usevu pet linija kukuruza, praÄenjem vizuelnih promena na samim gajenim biljakama (EWRC) i prinosa zrna. Herbicidi su primenjeni u koliÄinama preporuÄenim za proizvodnju hibridnog kukuruza, kao i u dvostruko veÄim. Triketonski herbicidi (mezotrion i topramezon) nisu izazvali znaÄajna oÅ”teÄenja na ispitivanim linijama, za razliku od sulfonilurea herbicida (rimsulfuron i foramsulfuron). Prinos zrna linija kukuruza pod uticajem sulfonilurea je znaÄajno varirao, najviÅ”e kod linija ranih grupa zrenja. Triketonski herbicidi nisu imali uticaja na prinos zrna ispitivanih linija kukuruza
Efekat interakcije genotipa i gustine setve na rodnost kukuruza na navodnjavanom Äernozemu
The aim of these studies was to determine the number of plants per hectare that would provide the maximum utilization of the genetic yielding potential of maize hybrids belonging to different FAO maturity groups and would also contribute to a rational use of seeds. The two-factorial trial was performed on irrigated chernozem in the period 2006-2008, according to the split-plot method with four replicates. Hybrids ZP 578 (FAO 500) and ZP 735 (FAO 700) observed in the combination with seven sowing densities (G1 - 40,816 plants ha-1, G2 - 50,125 plants ha-1, G3 - 59,524 plants ha-1, G4 - 69,686 plants ha-1, G5 - 79,365 plants ha-1, G6 - 86,286 plants ha-1 and G7 - 98,522 plants ha-1). Gained results show that statistically very significant differences in maize grain yields were obtained between the studied hybrids and the sowing densities. The lowest yields were recorded for all studied hybrids at the lowest sowing density (40,861 plants ha-1). The yield projection shows that the maximum grain yield of the hybrid ZP 578, i.e. hybrid ZP 735 can be expected at the level of 13.53 t ha-1, i.e. 12.86 t ha-1 at the sowing density of 84,000 plants ha-1, i.e. 72,000 ZP plants ha-1, respectively. In accordance with the rational use of seeds, high yields are obtained by sowing that provides 60,000 plants of ZP 578 ha-1 and 50,000 plants of ZP 735 ha-1.Cilj prouÄavanja bio je da se utvrdi broj biljaka po hektaru koji stvara uslove za maksimalno koriÅ”Äenje genetiÄkog potencijala rodnosti dva hibrida kukuruza razliÄite FAO grupe zrenja i ujedno doprinosi racionalnoj upotrebi semena. Dvofaktorijalni ogled izveden je u periodu 2006-2008 na navodnjavanom Äernozemu, po metodi razdeljenih parcela u Äetiri ponavljanja. Isptitivani su hibridi ZP 578 (FAO 500) i ZP 735 (FAO 700) u kombinaciji setve sa sedam gustina (G1 - 40,816 bilj. ha-1, G2 - 50,125 bilj. ha-1, G3 - 59,524 bilj. ha-1, G4 - 69,686 bilj. ha-1, G5 - 79,365 bilj. ha-1, G6 - 86,286 bilj. ha-1 and G7 - 98,522 bilj. ha-1). Dobijeni rezultati pokazuju da su izmeÄu ispitivanih hibrida i gustina setve ostvarene statistiÄki veoma znaÄajne razlike prinosa zrna kukuruza. Najniže prinose ispitivani hibridi su ostvarili pri najmanjoj gustini setve (40,816 bilj. ha-1). Projekcija prinosa pokazuje da se maksimalan prinos zrna hibrida ZP 578 može oÄekivati na nivou 13,53 t ha-1 pri gustini setve 84.000 bilj. ha-1, a 12,86 t ha-1 hibrida ZP 735 pri gustini 72.000 bilj ha-1. U skladu sa racionalnom upotrebom semena, visoki prinosi hibrida ZP 578 obezbeÄuju se sklopom sa 60.000 biljaka, a hibrida ZP 735 sa 50.000 biljaka po hektaru