Behaviour of end-plate moment connections with four bolts per row

У овом раду спроведене су опсежна експериментална и нумеричка испитивања понашања веза са чеоном плочом и четири завртња у реду, као и карактеристичне компоненте ових веза - Т-елемента. Експериментална испитивања укључују тестирања 36 узорака Т-елемената у природној величини, као и четири везе греда-стуб са чеоном плочом и четири завртња у реду, такође у природној величини. Нумеричке анализе, спроведене у софтверском пакету ABAQUS, су обухватале све типове нелинеарности, али и отказ материјала, те се као такве сврставају међу ретке којима су слични проблеми нумерички испитивани. Параметарска студија обухвата 33 различите конфигурације Т-елемената са четири завртња и представља највећу такву студију изведену за ову компоненту. Као основни још увек нерешен проблем, круцијалан за понашање Т-елемената, препознати су положај сила услед ефеката полуге, али и савијање завтњева. Приказан је и предложен нови аналитички модел прорачуна носивости Т-елемената са четири завртња, и квантификована његова предност над до сада постојећим моделима.U ovom radu sprovedene su opsežna eksperimentalna i numerička ispitivanja ponašanja veza sa čeonom pločom i četiri zavrtnja u redu, kao i karakteristične komponente ovih veza - T-elementa. Eksperimentalna ispitivanja uključuju testiranja 36 uzoraka T-elemenata u prirodnoj veličini, kao i četiri veze greda-stub sa čeonom pločom i četiri zavrtnja u redu, takođe u prirodnoj veličini. Numeričke analize, sprovedene u softverskom paketu ABAQUS, su obuhvatale sve tipove nelinearnosti, ali i otkaz materijala, te se kao takve svrstavaju među retke kojima su slični problemi numerički ispitivani. Parametarska studija obuhvata 33 različite konfiguracije T-elemenata sa četiri zavrtnja i predstavlja najveću takvu studiju izvedenu za ovu komponentu. Kao osnovni još uvek nerešen problem, krucijalan za ponašanje T-elemenata, prepoznati su položaj sila usled efekata poluge, ali i savijanje zavtnjeva. Prikazan je i predložen novi analitički model proračuna nosivosti T-elemenata sa četiri zavrtnja, i kvantifikovana njegova prednost nad do sada postojećim modelima.In this research, extensive experimental and numerical investigations of behaviour of end-plate moment connection with four bolts per row are performed, as well as specific component of the connection – T-stub element. Experimental research comprises tests on 36 unscaled specimens of T-stub elements and 4 specimens of beam-to-column joints with end-plate connection and four bolts per row, also in full-size. Numerical analyses, performed with software ABAQUS, included all types of nonlinearities, and material deterioration, hence they can be considered as one of the few most sophisticated analyses used for investigation of the considered problem. The parametric study comprises 33 different configurations of the T-stub element with four bolts per row and it presents the biggest study of this kind for this type of component. Bending of the bolts and position of the prying forces are recognized as the largest, still unsolved problem, crucial for the behavior of the T-stub elements. A new theoretical model for the resistance of the T-stub element with four bolts per row is proposed and its advantage over the existing models is presented and quantified

Behaviour of end-plate moment connections with four bolts per row

У овом раду спроведене су опсежна експериментална и нумеричка испитивања понашања веза са чеоном плочом и четири завртња у реду, као и карактеристичне компоненте ових веза - Т-елемента. Експериментална испитивања укључују тестирања 36 узорака Т-елемената у природној величини, као и четири везе греда-стуб са чеоном плочом и четири завртња у реду, такође у природној величини. Нумеричке анализе, спроведене у софтверском пакету ABAQUS, су обухватале све типове нелинеарности, али и отказ материјала, те се као такве сврставају међу ретке којима су слични проблеми нумерички испитивани. Параметарска студија обухвата 33 различите конфигурације Т-елемената са четири завртња и представља највећу такву студију изведену за ову компоненту. Као основни још увек нерешен проблем, круцијалан за понашање Т-елемената, препознати су положај сила услед ефеката полуге, али и савијање завтњева. Приказан је и предложен нови аналитички модел прорачуна носивости Т-елемената са четири завртња, и квантификована његова предност над до сада постојећим моделима.U ovom radu sprovedene su opsežna eksperimentalna i numerička ispitivanja ponašanja veza sa čeonom pločom i četiri zavrtnja u redu, kao i karakteristične komponente ovih veza - T-elementa. Eksperimentalna ispitivanja uključuju testiranja 36 uzoraka T-elemenata u prirodnoj veličini, kao i četiri veze greda-stub sa čeonom pločom i četiri zavrtnja u redu, takođe u prirodnoj veličini. Numeričke analize, sprovedene u softverskom paketu ABAQUS, su obuhvatale sve tipove nelinearnosti, ali i otkaz materijala, te se kao takve svrstavaju među retke kojima su slični problemi numerički ispitivani. Parametarska studija obuhvata 33 različite konfiguracije T-elemenata sa četiri zavrtnja i predstavlja najveću takvu studiju izvedenu za ovu komponentu. Kao osnovni još uvek nerešen problem, krucijalan za ponašanje T-elemenata, prepoznati su položaj sila usled efekata poluge, ali i savijanje zavtnjeva. Prikazan je i predložen novi analitički model proračuna nosivosti T-elemenata sa četiri zavrtnja, i kvantifikovana njegova prednost nad do sada postojećim modelima.In this research, extensive experimental and numerical investigations of behaviour of end-plate moment connection with four bolts per row are performed, as well as specific component of the connection – T-stub element. Experimental research comprises tests on 36 unscaled specimens of T-stub elements and 4 specimens of beam-to-column joints with end-plate connection and four bolts per row, also in full-size. Numerical analyses, performed with software ABAQUS, included all types of nonlinearities, and material deterioration, hence they can be considered as one of the few most sophisticated analyses used for investigation of the considered problem. The parametric study comprises 33 different configurations of the T-stub element with four bolts per row and it presents the biggest study of this kind for this type of component. Bending of the bolts and position of the prying forces are recognized as the largest, still unsolved problem, crucial for the behavior of the T-stub elements. A new theoretical model for the resistance of the T-stub element with four bolts per row is proposed and its advantage over the existing models is presented and quantified

Significance of clinical parameters and treatment methods for prognosis and postoperative outcome of rhegmatogenous retinal detachment

Introduction: Rhegmatogenous retinal detachment (RRD) represents separation of neurosensory retina from retinal pigment epithelium, which is sight threatening condition. The procedures for surgical management of RRD are scleral buckle and pars plana vitrectomy (PPV). Various factors may affect the success of surgery and postoperative outcome. Patients with RRD represent one of the most difficult cases for surgical treatment, while postoperative visual recovery is not always complete. Aim: The aim of this study was to analyze the methods of treatment of patients with RRD, and clinical parameters relevant for prognosis and postoperative outcome. Material and methods: Retrospective study conducted at the Department of Ophthalmology, Clinical Center of Serbia, in Belgrade, from January 1. 2016 to December 31. 2016, included 203 consecutive patients hospitalized for RRD. The statistical analysis of the results on anatomical and functional outcome of operation, obtained from medical records, was carried out by t-test, Wilcoxon test and x2 test. Results: Scleral buckle was method of choice in treatment of 56.65% patients, while PPV was performed in 43.35% of patients. Retina was successfully reapplied at 88.7% of patients treated with scleral buckle and 67% operated with PPV method. Parameters that influenced the anatomical success included: number of retinal ruptures (p = 0.022) and macular attachment (p < 0.001). Statistically significant increase in postoperative visual acuity, compared to the measured preoperative visual acuity (p < 0.001) was shown. Functional success was evaluated using postoperative visual acuity and depended on: macular attachment, number of retinal ruptures and type of performed surgery. Conclusion: The presented results show that patients with RRD can have a good anatomical and functional recovery, especially those cases with a single retinal rupture and macula-on. Therefore, it is important to urgently refer patients with RRD to the surgical treatment, before it comes to the separation of the macula, in order to achieve better postoperative results

USAGLAŠENOST ZAKONODAVSTVA U OBLASTI ŽIVOTNE SREDINE U REPUBLICI SRBIJI SA PREPORUKOM EVROPSKE UNIJE O INSPEKCIJSKOM NADZORU

Republic of Serbia’s obligations in process of joining European Union include harmonizing national regulations, institutions and operational practices with the requirements in the EU, legal inheritance of EU (acquis communautaire). Republic of Serbia, in the previous period, significantly improved its position in the transposition of legal inheritance of EU within environmental field and this significant process was initiated by the adoption of a number of systematic laws and laws within fled. In the EU states and our country, authorities in charge of inspection ensure the implementation of existing regulations in the area of environment. Recommendation of the minimal criteria for the ecological inspection in the EU countries (RMCEI) takes significant role in the area of supervision. Subject of this thesis are features of this Recommendation and harmonizing of Republic of Serbia ecological inspections with its directives.Obaveze Republike Srbije u procesu pridruživanja Evropskoj uniji, podrazumevaju usklađivanje nacionalnih propisa, institucionalnih organizacija i radnih praksi sa zahtevima propisanim u EU propisima, pravnim tekovinama EU (acquis communautaire). U prethodnom periodu Republika Srbija je znatno napredovala u transpoziciji pravnih tekovina EU iz oblasti životne sredine i to usvajanjem brojnih sistemskih i sektorskih zakona, na koji način je ovaj značajan proces započet. U državama članicama EU i u našoj državi, inspekcijski organi svojim kontrolama obezbeđuju primenu važećih propisa iz oblasti životne sredine. Preporuka o minimalnim kriterijumima za inspekciju za zaštitu životne sredine u državama članicama EU (RMCEI), zauzima značajnu ulogu u oblasti inspekcijskog nadzora. Tema ovog rada su karakteristike ove Preporuke i usaglašenost inspekcije za zaštitu životne sredine Republike Srbije sa njenim smernicama

Efficacy and safety of triamcinolone acetonide posterior subtenon injection in patients with diabetic maculopathy

Introduction: Diabetic maculopathy (DM) is the main cause of visual impairment of the working population. Optical coherence tomography and fluorescein angiography give us a precise insight into retinal changes. In recent years, pharmacological treatment of DM is increasing. Posterior subtenon application is accompanied by a smaller percentage of complications compared to intravitreal application. Aim: The aim is to assess the efficacy and safety of triamcinolone acetonide (TA) posterior subtenon injection in the treatment of DM, by measuring intraocular pressure (IOP), central macular thickness (CMT) and visual acuity, before and two months after. Material and methods: The retrospective study included 49 patients admitted during 2016, for posterior subtenon injection of TA in the DM treatment, at Daily Hospital, for the treatment of vascular diseases of the eye and the macula Department of Ophthalmology, Clinical Center of Serbia. Data were collected from medical records on gender, age, type of retinopathy and visual acuity, IOP and CMT, before and two months after intervention. Results: The average age of patients was 63 ± 9.5 years. Out of 49 patients tested, 30.61% were female and 69.39 % were male. The frequency of non-proliferative diabetic retinopathy (NPDR) in the study was 53.6%. There was a statistically significant difference in visual acuity and CMT, before and two months after the intervention, but there was no correlation between the improvement of visual acuity and CMT reduction. There was no statistically significant difference in IOP, before and two months after intervention. Conclusion: The most common type of diabetic retinopathy in this study was NPDR. After posterior subtenon application of TA, there was a significant increase in visual acuity and CMT reduction, but reduction of CMT is not connected with the increase of visual acuity. Posterior subtenon TA application is not accompanied by a significant increase in IOP, and it is an effective and relatively safe way of treating DM

Uticaj agroekoloških uslova i hibridne kombinacije na klijavost semena kukuruza

Germination energy and seed germination of four maize combinations cultivated under different growing conditions were observed. Analysis of hybrid seed of four commercial combinations derived at the Maize Research Institute, Zemun Polje, grown in three locations, were done on the working sample of 4 x 100 seeds under laboratory conditions. The experimental data was processed for the mean and total variability (X and C.V.) for both seed traits and for each test variant. The total average values of germination energy and germination in the period of investigation amounted to 94.5% and 94.8%, respectively. The coefficient of variation for germination energy was 0.67%, while for germination it was 0.39%. In the five-year study, the hybrid combination ZP704 had the highest values of germination energy (95.9%) and total germination (96.3%).Test results indicate that coefficients of variations for both observed traits over years were low, which points out to homogeneity of the material. Significant effects of factors (hybrid and location) and their interaction on observed seed properties were established by the analysis of variance. Gained results indicate that all four hybrids had high level of expression of traits under changeable agroecological conditions, as well as, a great effect of factors (hybrid and location) on germination energy and seed germination.U ovim istraživanja proučavane su energija klijanja i klijavost semena kukuruza četiri genotipske kombinacije u različitim agroekološkim uslovima uspevanja. Analize hirbidnog semena četiri komercijalne kombinacije Instituta za kukuruz Zemun Polje, proizvedene na tri lokaliteta, urađene su u laboratorijskim uslovima na radnom uzorku 4 x 100 semena. Eksperimentalni podaci obrađeni su na srednju vrednost i ukupnu varijabilnost (X i C.V.) za obe osobine semena i svaku varijantu istraživanja. Ukupna prosečna vrednost energije klijanja u posmatranom periodu bila je 94.5%, a klijavost 94.8%. Koeficijent varijacije za energiju iznosio je 0.67%, a za klijavost 0.39%. Hibridna kombinacija ZP704 u petogodišnjim istraživanjima imala je najviši nivo energije klijanja (95.9%) i ukupne klijavosti (96.3%). Rezultati testova ukazuju da koeficijenti varijacije ispitivanih karakteristika kod obe osobine su mali i ukazuju na homogenost materijala. Dvofaktorijalnom analizom varijanse utvrđen je značajan uticaj faktora (hibrid i lokacija), kao i njihova interakcija na ispitivane osobine semena. Dobijeni rezultati pokazali su da sva četiri hibrida imaju visok nivo ispoljavanja ispitivanih osobina u promenljivim agroekološkim uslovima, kao i visok uticaj faktora ( hibrid i lokalitet) na energiju i klijavost semena

Primena različitih sistema za fiksiranje protetičkih rešenja na implantatima - prikaz slučaja

Implantology has become an important therapeutic procedure that allows complete aesthetic and functional rehabilitation of the oro-facial system in edentulous patients. Implant supported prosthetic restorations can be fixed in two ways, by cement or screws. Both techniques have advantages and disadvantages and their selection depend on situation in patient’s mouth. The aim of this study was to describe complete process of prosthetic rehabilitation in an edentulous patient, from pre-implant preparation, through implant placement and fixation of final restoration on implants. In this case report, one ceramo-metal bridge was fixed by screws in the lower jaw while the other one was fixed using glass-ionomer cement in the upper jaw. After bone augmentation and time necessary for its osseointegration (6 to 8 months), 16 implants were placed in both jaws. Eight weeks after the implant placement, final prosthetic rehabilitation was achieved by cementation of one ceramo-metal bridge in the upper jaw using glass ionomer cement and fixation of the second bridge with screws in the lower jaw. To achieve successful implant supported prosthetic rehabilitation, the treatment protocol must be followed from the beginning to the end of the therapy.Ugradnja implantata je danas vrlo važna terapijska procedura u stomatološkom zbrinjavanju pacijenata bez zuba zbog mogućnosti potpune estetske i funkcionalne rehabilitacije orofacijalnog sistema. Protetičku restauraciju na ugrađenim implantatima moguće je fiksirati na dva načina: cementiranjem ili pomoću šrafova. Obe tehnike imaju prednosti i mane, a njihov izbor zavisi od stanja u ustima pacijenta. Cilj ovog rada bio da se prikaže celokupan postupak zbrinjavanja pacijenta bez zuba, počev od preimplantološke pripreme, preko ugradnje implantata, do fiksiranja završenog protetičkog rada na implantatima. Kod pacijenta je u donjoj vilici postavljen metalokeramički most na osnovi fiksiranoj šrafom, dok je u gornjoj vilici most fiksiran glasjonomer-cementom. Nakon ugradnje veštačke kosti i vremena neophodnog za njenu oseointegraciju (od šest do osam meseci), postavljeno je 16 implantata u gornjoj i donjoj vilici. Osam nedelja od ugradnje implantata urađena je konačna protetička rehabilitacija pacijenta, koja je završena cementiranjem jednog metalokeramičkog mosta u gornjoj vilici glasjonomer-cementom, te fiksiranjem drugog mosta pomoću šrafova u donjoj vilici. Da bi se postigla uspešna protetička rehabilitacija pacijenta pomoću implantata, potrebno je pridržavati se protokola od početka do kraja terapije

Arsenic removal from water using low-cost adsorbents: A comparative study

Inorganic arsenic removal from water using low-cost adsorbents is presented in this paper. Selective removal of As(III) and As(V) from water was performed with natural materials (zeolite, bentonite, sepiolite, pyrolusite and limonite) and industrial by-products (waste filter sand as a water treatment residual and blast furnace slag from steel production); all inexpensive and locally available. Kinetic and equilibrium studies were realized using batch system techniques under conditions that are likely to occur in real water treatment systems. The natural zeolite and the industrial by-products were found to be good and inexpensive sorbents for arsenic while bentonite and sepiolite clays showed little affinity towards arsenic. The highest maximum sorption capacities were obtained for natural zeolite, 4.07 mg As(V) g-1, and waste iron slag, 4.04 mg As(V) g-1

Gas chromatography-mass spectrometry system applied to determine botanical origin of various types of edible vegetable oils

This study represents a new strategy for discrimination of 59 samples of various cold-pressed, virgin and refined edible vegetable oils according to the corresponding botanical origin. Samples were produced from 17 plant species: olive, sunflower, safflower, flax, pumpkin, sesame, hemp, walnut, hazelnut, almond, grape, black cumin, apricot, plum, soybean, wheat and rapeseed. A GC/MS device performing in a ion current (IC) mode, combined with multivariate clustering, was employed in the analysis. Derivatization reaction occurred in the injector of a gas chromatograph. The discriminations between species were based on marker-peaks of 9 molecular ions of dominant fatty acid methyl esters (FAMEs), which were chosen as descriptors: m/z 268, 270, 292, 294, 296, 298, 324, 326 and 354. Dendrogram obtained after performing cluster analysis shows clear discriminations of the analyzed samples, based on the belonging botanical origin. These results demonstrate that IC-GC/MS approach with cluster analysis could be a useful tool in rapid screening for botanical origin of commercial samples of various edible vegetable oils