Primena 3D kompatibilnih materijala u građevinarstvu

Zbornik radova Građevinskog fakultet

Skupljanje betona na bazi recikliranog agregata

The application of recycled concrete aggregate in concrete structures is necessary for the achievement of sustainable construction and a reduction in the negative environmental impacts. This paper presents the most significant research into the phenomenon of shrinkage of recycled aggregate concretes. Since the amount of research is still relatively small, this paper presents an attempt to systematize them, present their results and analyze them. It is shown that the shrinkage of recycled aggregate concrete is mostly larger than the shrinkage of the reference natural aggregate concrete and that this difference increases as the percentage of recycled concrete aggregate increases. The effect of the water-to- cement ratio has also been analysed.Primena recikliranog agregata u armirano-betonskim konstrukcijama je nužna ako se želi postići održiva gradnja i smanjenje negativnih uticaja eksploatacije prirodnih resursa na životnu okolinu. U ovom radu su predstavljena značajna istraživanja fenomena skupljanja betona na bazi recikliranog agregata. Istraživanja u ovoj oblasti su i dalje relativno malobrojna. U ovom radu je izvršeno njihovo grupisanje, prezentacija, kao i analiza rezultata. Pokazano je da su skupljanja betona na bazi recikliranog agregata po pravilu veća od uporednih betona na bazi prirodnog agregata i da rastu sa procentom zamene prirodnog agregata recikliranim. Analiziran je i uticaj vodocementnog faktora na skupljanje

Žuta rđa preti da prepolovi prinos pšenice

In the 2013/14 production year, there was a strong appearance of rust on wheat at several locations in Vojvodina and Serbia. According to symptoms, colors, shapes and sizes of urediospores and teliospores the causal agent of yellow rust Puccinia striiformis f. sp. tritici dominated. The infection intensities ranged from 40 to 60% on some field sites, and at the genetic collection field trials intensities were up to 90%. This pathogen has not been a major issue in the Serbia wheat production, and there is no study of the virulence of its population. There has been report of the emergence of new races of yellow rust in England, France, Spain, Germany, Sweden and Denmark. This pathogen rapidly spreads through the wind and passengers from all over the world and a new race for a very short period of time can pass from one continent to the other. All that facts are reasons for a serious suspicion that there is the appearance of the new race(s) of yellow rust on wheat in Serbia.U proizvodnoj 2013/14. godini, na više lokaliteta u Vojvodini i Srbiji, došlo je do jače pojave rđa na pšenici. Na osnovu simptomatoloških karakteristika, boje, oblika i veličine uredo i teleutospora, dominira Puccinia striiformis f. sp. tritici - prouzrokovač žute rđe. Na pojedinim parcelama u proizvodnji intenzitet zaraze kreće se od 40 do 60%, a u genetskoj kolekciji na Rimskim Šančevima i do 90%. Ovaj patogen do sada nije predstavljao veći problem u proizvodnji pšenice u Srbiji, pa se nije ni radilo na proučavanju virulentnosti njegove populacije. U Engleskoj, Francuskoj, Španiji, Nemačkoj, Švedskoj i Danskoj je došlo do pojave novih rasa žute rđe. Ovaj patogen veoma brzo se širi putem vetra i putnika i nova rasa za veoma kratko vreme može sa jednog kontinenta preći na drugi kraj sveta. Iz tih razloga postoje opravdane sumnje da je u Srbiji došlo do pojave nekih od već opisanih ili do pojave nove ili novih rasa žute rđe na pšenici

EFFECTS OF THE SCHROTH METHOD IN CHILDREN WITH IDIOPATHIC SCOLIOSIS

Scoliosis is a multifactorial three-dimensional (3D) spinal deformation which always includes elementary deformations on three planes: a lateral curvature on the frontal plane, loss of natural physiological curvature on the sagittal plane and, in most cases, increase of lordosis in the lumbosacral joint (hyperlordosis), and a (very typical) vertebral axial rotation on the horizontal plane. One of the best methods in scoliosis correction is the Schroth method. In view of the above, the objective of this study is to identify the effects of the Schroth method on correcting functional-motor status in children with adolescent idiopathic scoliosis (IS). The participant sample comprised 20 children, of an average age of 14.5, who took part in the 10-day Schroth Camp. The following measure instruments were used for the assessment of the effect of the Schroth method: the Sorensen test, the Sit-and-reach test, and height assessment. Statistically significant improvements were identified across the results of all three tests, for the Sorensen test: 45.6±19.29 s, the Sit-and-reach test: 4.05±2.25 cm, and height 1.4±0.66 cm. It can be concluded that the conducted Schroth method exercise program exerted a positive effect on improving motor functionality, as well as enhancing flexibility and isometric endurance of the lumbar extensors of the spine. Additionally, there was an increase in height, which indicates a positive effect in terms of the functionality and symmetry of the left and right sides of the body, and in terms of improved posture on the frontal and sagittal planes

Stamena, ozima sorta pšenice

Stamena is a winter wheat variety developed at the Institute of Field and Vegetable Crops in Novi Sad, Yugoslavia. It was released by the Federal Commission for varietals Approval in 1999. Stamena was developed by crossing genetically divergent and highly productive parents Lasta and Rodna (Breeders: T. Mišić. N. Mladenov, Z. Jerković and R. Jevtić). Spike is white, smooth, awn less, medium compact with 18-21 spike lets. The grain is vitreous and dark red (Triticum aestivum L. ssp. vulgar e var. lutescens). Stamena is a medium early variety, 1 day earlier than Partizanka and 3 days earlier than Jugoslavija (Table 4). It has excellent resistance to winterkilling, as in very winter hardy Partizanka. The average stem height is 78 cm, with a good resistance to lodging. Stamena has field resistance to leaf rust (Pucce, recondita tritict), horizontal resistance, which is the type of resistance that modern wheat breeding is interested in. The resistance to stem rust (Pucce, graminis tritict) is good and to powdery mildew (Erysiphegraminis tritici) very good. The 1000 grain mass is about 32 g and volume grain mass 81.3 kg/hi. (Table 2). Stamena is classified in the subgroup A-l. It has excellent milling and baking quality and it belong to the 1st technological group (quality enhancer). The quantity of dry gluten is about 9%. The variety Stamena is a very productive, with the genetic potential for grain above 11 t/ha suitable for growing on fertile and less fertile soils. It has started to be grown commercially in 2000.Ozima, srednje rana sorta pšenice Stamena, oplemenjena je metodom proste hibridizacije genetički divergentnih roditelja, sorti Lasta i Rodna. U njoj su vrlo uspešno kombinovani geni koji kontrolišu glavne agronomske osobine: potencijal prinosa zrna iznad 11 t/ha, odličan tehnološki kvalitet na nivou poboljšivača, visoka otpornost prema niskim temperaturama i mrazu kao i pojavama koje prate mraz (golomrazici i suvomrazici), poljska otpornost prema prouzrokovaču lisne rđe (Pucce. recondita tritict) i dobra otpornost prema stabljičnoj rđi i vrlo dobra prema pepelnici (Pucce. graminis tritici, Erysiphe graminis tritici), srednje niska stabljika, oko 78 cm visine i dobra otpornost prema poleganju. Ističe se velikom biološkom plastičnošću i sposobnošću adaptacije različitim klimatsko-zemljišnim uslovima. Vrlo je perspektivna sorta. Registrovanje od strane Savezne komisije za priznavanje sorti 1999 godine (selekcioneri T. Mišić, N. Mladenov. Z. Jerković i R.Jevtić)

Incidence and impact of neck pain on daily life activities of the student population

Introduction: Neck pain (NP) may have a local mechanical (non-specific) origin caused by dysfunction of the joint, muscle, and ligament structures in the neck or by a discogenic etiology. Most people (50–60%) suffer from NP at some point in their lives. They are more common in highly developed countries and in urban areas. The aim of this study is to determine the prevalence of NP and its impact on daily living activities in the student population. Methods: The study included students of the University of Sarajevo - Faculty of Health Studies in the period from May 2021 to June 2021. The sample of respondents was formed by the method of random selection and included respondents of both sexes, aged 19–28 years. The study was conducted as a transversal cross-sectional study at a specific time point on the frequency of NP and the ability to perform activities of daily living in the student population. Results: Out of the total number of 255 respondents, 77 (30.2%) reported that they have NP while 178 (69.8%) respondents reported that they do not feel NP and it was found that there was no statistically significant difference between the age groups of the subjects with and without NP. The study concluded that a higher percentage of respondents with NP did not engage in leisure activities and that respondents with NP had lower mobility in daily life, sleep disturbance, and poorer ability to perform activities of daily living due to NP. Conclusion: The study conducted revealed that a significant percentage of the student population with NP has a lower ability to perform activities of daily living. Considering the above facts and the current transformation of the educational model, in which static postures dominate, it is necessary to design and implement programs for targeted physical activity and prevention of long-term inactivity that leads to painful musculoskeletal syndromes

The investigation of the presence of Clostridium botulinum spores in honey in Serbia

The presence of Clostridium botulinum spores in 59 honey samples originating from different regions of the Republic of Serbia was studied. In addition to microbiological methods, after enrichment, centrifugation and membrane filtration, molecular methods (PCR methods) were utilized. The number of spores in PCR positive samples was estimated by the most probable number (MPN) method. PCR confirmed C. botulinum spores in 5 (8.47%) honey samples. MPN of spores varied from 20/kg to 204/kg honey. PCR was more sensitive than cultural methods. Natural honey contamination with C. botulinum spores is low-level and not homogeneous, and therefore, PCR methods require multiple sub-sampling

Vodič za organsku proizvodnju pšenice

Pšenica spada u najznačajnije gajene biljne vrste. U svetskim razmerama, pored pirinča, pšenica se najviše koristi u ljudskoj ishrani. Pšeničnim hlebom se hrani preko 70% svetskog stanovništva. U konvencionalnoj proizvodnji, u Srbiji, pšenica se gaji na 500-550 hiljada hektara. Površine pod organskom proizvodnjom pšenice u 2010. godini iznosile su 234 ha, odnosno 5% od ukupne površine pod organskom proizvodnjom u Srbiji (März i sar., 2012). Izuzetno povoljni agroekološki uslovi, pored zadovoljavajućeg prinosa, omogućuju i postizanje odličnog tehnološkog kvaliteta. Zahvaljujući osobinama rezervnih proteina u endospermu zrna (glijadini i glutenini), pšenični hleb je idealna hrana za ljudsku populaciju. Kompleksan hemijski sastav, koji čine esencijalne aminokiseline, skrob, šećeri, celuloza, masti, vitamini i mineralne materije, doprinose velikom značaju pšenice u sistemu zdrave ishrane. Pored toga, proizvodnja testenina od durum pšenice ili bezglutenskih proizvoda od spelta pšenice, utiču na veću zastupljenost pšenice u setvenoj strukturi. Imajući u vidu veću potražnju i veliki značaj korišćenja integralnih proizvoda (od celog zrna) u ljudskoj ishrani, pored odličnog useva u plodoredu i plodosmeni, pšenica postaje sve zahvalnija i profitabilnija strnina u organskoj proizvodnji

Simulation methods approach to designing lasers of interest in ecology

Prema tipu primene lasera počinje se zadatak sa odabirom pogodnog kvantnog generatora, a zatim sledi koncepcija dizajna izabrane metode. Prema kompleksnosti sistema simuacije u procesu dizajniranja i procene uspešnosti, zamišljene koncepcije imaju veliku ulogu, pošto su cene razvoja sistema često u širokim granicama. U radu se razmatraju izabrani zahtevi i algoritmi, koji ih prate, kao delovi programskih paketa ili pojedinačno razvijenih sopstvenih rešenja. Izabrane su problematike iz dizajna sistema primene lasera kod interferometara, neki lidarski – ekološki problemi, i problematika kontrole požara, koja se ostvaruje primenom lidarskih sistema.The task of the laser application start with selection of adequate quantum generator, and the second step is the design of a chosen method. The wide cost range of the system development and simulation complexity in the designing process, result in the overall evaluation of conception efficiency. The chosen demandes and according algorithms as well as software packages, or own software solutions are presented in this paper. Design problems of laser systems in interferometers, some lidar-ecology applications, and the fire detection and monitoring accomplished by lidar systems, are analysed, too