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 pomoću mikrobne kulture nitrifikanata i denitrifikanata. Cilj rada je bio ukloniti nitrat koristeći organske sastojke iz otpadne vode industrije prerade mlijeka kao elektron donore. Minimalan omjer KPK/ NO3-N (KPK-kemijska potrošnja kisika/NO3-N-nitratni dušik) potreban za postizanje potpune redukcije NO3-N iznosi 10. Mikrobna kultura nitrifikanata i denitrifikanata, prethodno prilagođena na otpadnu vodu mljekarske industrije, provodi redukciju nitrata uz različitu brzinu iskorištenja supstrata. U početku denitrifikacije mikrobna kultura troši 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 pomoću mikrobne kulture nitrifikanata i denitrifikanata. Cilj rada je bio ukloniti nitrat koristeći organske sastojke iz otpadne vode industrije prerade mlijeka kao elektron donore. Minimalan omjer KPK/ NO3-N (KPK-kemijska potrošnja kisika/NO3-N-nitratni dušik) potreban za postizanje potpune redukcije NO3-N iznosi 10. Mikrobna kultura nitrifikanata i denitrifikanata, prethodno prilagođena na otpadnu vodu mljekarske industrije, provodi redukciju nitrata uz različitu brzinu iskorištenja supstrata. U početku denitrifikacije mikrobna kultura troši 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 području Južnojadranske kotline 2008. odnosno 2010. godine. Ovi nalazi proširuju saznanja o distribuciji ove rijetke dubokomorske vrste čija je prisutnost u Sredozemnom moru tek nedavno utvrđena

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.Proučavanja 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 uspešno gajenje useva uz istovremenu kontrolu korova i drugih štetnih organizama. Smena širokoredih useva i strnina, leguminoza i žita omogućava primenu herbicida sa različitim mehanizmima delovanja čime se direktno utiče na zastupljenost korova. Osim broja i vrste useva koje ulaze u sastav plodoreda, veoma je važan i njihov redosled u rotaciji, jer će mere koje se primenjuju u prethodnom usevu imati efekat i na naredne useve. U ogledu je proučavan uticaj monokulture i dva tropoljna plodoreda kukuruz- pšenica-soja i kukuruz-soja-pšenica uz primenu herbicida, na zastupljenost jednogodišnjih i višegodišnjih korova u kukuruzu. U pogledu kontrole zakorovljenosti, najbolji efekat je ispoljio tropoljni plodored kukuruz-soja-pšenica, posebno uz primenu herbicida u preporučenoj količini. Nakon jedne rotacije useva, biomasa jednogodišnjih, a naročito višegodišnjih korova je značajno smanjena u svim varijantama primene herbicida. Pšenica 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 soybean–common 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 početkom novog tisućljeća više se ne može zamisliti bez računala. Inženjeri koji u svom radu koriste računala ili neke druge ekrane za promatranje, kako za projektiranje, tako i u fazama rada u proizvodnji, izloženi su utjecaju sindroma računalnog oka. U ovom radu definiran je sindrom računalnog oka, objašnjen je njegov nastanak i izložene su njegove posljedice. U središnjem dijelu rada dani su rezultati istraživanja provedenog u Republici Srbiji o pitanju poznavanja korisnika računala, uočenim simptomima ovog sindroma i postojanju sindroma računalnog oka. Na kraju rada izložena su rješenja za smanjenje i sprječavanje 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

Značaj 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 isn’t 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 narušavanja odnosa u agroekosistemu. Radi smanjenja štetnog delovanja herbicida, u svetu i kod nas se poslednjih godina sve više preporučuje kombinovana primena više 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, mehaničkih, hemijskih, bioloških i drugih mera. S obzirom da se u usevu kukuruza javlja veliki broj vrsta korova sa različitim životnim ciklusima i načinima preživljavanja, nerealno je očekivati da primena bilo koje mere pojedinačno može imati zadovoljavajući efekat u kontroli korova i smanjenju potencijalne zakorovljenosti kroz smanjenje rezervi semena i vegetativnih organa korovskih biljaka u zemljištu. 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 uništavanju, tj. iskorenjivanju korova, već o svođenju njihove brojnosti na nivo koji usev može da toleriše tako da prinos nije ugrožen a ravnoteža u agrosistemu nije radikalno narušena. Imajući sve navedeno u vidu, analizirani su efekti kombinovane primene različitih mera iz sistema integrisanih mera (plodored, obrada, đubrenje, gustina gajenja, izbor genotipa, primena herbicida) u kontroli korova u kukuruzu

Mogućnosti 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 odgovarajuću selektivnost prema usevu u kome se primenjuje. Ukoliko se selektivnost herbicida nedovoljno poznaje moguće je da dođe do oštećenja useva posle primene, što može dovesti i do gubitka prinosa. Tehnologija gajenja širokorednih 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, praćenjem vizuelnih promena na samim gajenim biljakama (EWRC) i prinosa zrna. Herbicidi su primenjeni u količinama preporučenim za proizvodnju hibridnog kukuruza, kao i u dvostruko većim. Triketonski herbicidi (mezotrion i topramezon) nisu izazvali značajna oštećenja na ispitivanim linijama, za razliku od sulfonilurea herbicida (rimsulfuron i foramsulfuron). Prinos zrna linija kukuruza pod uticajem sulfonilurea je značajno varirao, najviše 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 černozemu

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 proučavanja bio je da se utvrdi broj biljaka po hektaru koji stvara uslove za maksimalno korišćenje genetičkog potencijala rodnosti dva hibrida kukuruza različite FAO grupe zrenja i ujedno doprinosi racionalnoj upotrebi semena. Dvofaktorijalni ogled izveden je u periodu 2006-2008 na navodnjavanom černozemu, po metodi razdeljenih parcela u četiri 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 između ispitivanih hibrida i gustina setve ostvarene statistički veoma značajne 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 očekivati 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 obezbeđuju se sklopom sa 60.000 biljaka, a hibrida ZP 735 sa 50.000 biljaka po hektaru