Pushover analysis for seismic assessment of RC Nišava Bridge

Contemporary structural design implies nonlinear behavior of ductile members for design seismic action. Therefore, the application of nonlinear analysis in the aseismic design of structures is required. Nonlinear static (pushover) analysis has become a very popular tool for the seismic assessment of structural performance during a particular earthquake due to the lower computational cost and less time consuming in comparison to the nonlinear time-history analysis. The standard pushover analysis (SPA) has been extended to the modal pushover analysis (MPA) of buildings in order to consider higher modes effects. Since the higher modes usually play an important role in the seismic bridge analysis, the MPA has been adopted for the seismic assessment of bridges. In the paper, the MPA of the Nišava Bridge structure (233.2m long 7-span continuous bridge, curved in plan with R=540m and prestressed 13.75m wide bridge deck) has been performed in transverse direction, for two levels of excitation which are 2 and 3 times higher than the design level (a g =0.1g). For the horizontal component of the seismic action, elastic response spectrum, Type 2 for soil type B, according to EN1998-1 has been selected. Analyses considering different levels of excitation and different monitoring points are carried out using the SAP2000 commercial software package. The seismic demands of the structure (peak displacements of the deck in transverse direction), subjected to the monotonically increasing lateral forces have been calculated, considering five dominant transverse modes. Hinge distribution within the structure has been determined, too, for the target displacement obtained from the MPA. The overall performance of the bridge was very satisfactory. Neither local nor global failure was predicted, even under seismic actions that three times exceed the design level. The performed analysis showed that the fundamental transverse mode shape contributes to the final response significantly. The influence of higher modes is more pronounced for higher level of excitation

Pushover analysis for seismic assessment of RC Nišava Bridge

Contemporary structural design implies nonlinear behavior of ductile members for design seismic action. Therefore, the application of nonlinear analysis in the aseismic design of structures is required. Nonlinear static (pushover) analysis has become a very popular tool for the seismic assessment of structural performance during a particular earthquake due to the lower computational cost and less time consuming in comparison to the nonlinear time-history analysis. The standard pushover analysis (SPA) has been extended to the modal pushover analysis (MPA) of buildings in order to consider higher modes effects. Since the higher modes usually play an important role in the seismic bridge analysis, the MPA has been adopted for the seismic assessment of bridges. In the paper, the MPA of the Nišava Bridge structure (233.2m long 7-span continuous bridge, curved in plan with R=540m and prestressed 13.75m wide bridge deck) has been performed in transverse direction, for two levels of excitation which are 2 and 3 times higher than the design level (a g =0.1g). For the horizontal component of the seismic action, elastic response spectrum, Type 2 for soil type B, according to EN1998-1 has been selected. Analyses considering different levels of excitation and different monitoring points are carried out using the SAP2000 commercial software package. The seismic demands of the structure (peak displacements of the deck in transverse direction), subjected to the monotonically increasing lateral forces have been calculated, considering five dominant transverse modes. Hinge distribution within the structure has been determined, too, for the target displacement obtained from the MPA. The overall performance of the bridge was very satisfactory. Neither local nor global failure was predicted, even under seismic actions that three times exceed the design level. The performed analysis showed that the fundamental transverse mode shape contributes to the final response significantly. The influence of higher modes is more pronounced for higher level of excitation

Pegavost i sušenje lista - značajna bolest peršuna u Srbiji

In the period 2005-2014, total of 19 isolates of Alternaria petroselini originating from parsley leaves, taproot and seed, as well as infested soil were collected and analyzed on the bases of morphological, pathogenic and molecular features. All isolates formed dark gray colonies on PDA and subsurfacely produced microsclerotia, as well as pigmented, broadly ellipsoidal, singly feodyctiosporic conidia. Pathogenicity and host range studies using spore suspension spray inoculation, revealed that isolates were pathogenic for parsley, parsnip, celery and coriander, weakly pathogenic for carrot, fennel and anise, and not pathogenic for onion, cabbage, pepper, tomato, and cucumber. Molecular detection utilizing A. radicina specific primers failed to demonstrate difference between two closely related but diffe­rent species, A. radicina and A. petroselini. For further confirmation of idendty of Serbian A. petroselini isolates, sequencing of selected genomic fragments including ITS rDNA, Alt a1 and EF1a protein coding genes was performed. BLAST search revealed that the most reliable molecular delineation between A. petroselini and closely related species could be achieved on the bases of sequence analysis of Alt a1 and EF1a genes (25-27, and 10-12 nucleotide differences from A. radicina isolates, respectively), while sequence of ITS rDNA were helpful, but not completely informative for identification of A. petroselini isolates.U periodu od 2005. do 2014. godine, sakupljeno je 19 izolata Alternaria petroselini poreklom iz lista, korena i semena peršuna, kao i infestiranog zemljišta i analizirano na osnovu morfoloških, patogenih i molekularnih osobina. Svi izolati formirali su tamnosive kolonije na PDA i supstratno obrazovali mikrosklerocije, kao i obojene, elipsoidno okruglaste, feodiktiosporne konidije pojedinačno na kratkim konidioforama. Ispitujući patogenost i krug domaćina inokulacijom suspenzijom spora, svi ispitivani izolati ispoljili su patogenost za peršun, paštrnak, celer i korijander, slabu patogenost za mrkvu, morač i anis, a nisu bili infektivni za crni luk, kupus, papriku, paradajz i krastavac. Molekularna detekcija korišćenjem prajmera specifičnih za detekciju A. radicina nije uspela da napravi razliku između izolata dve srodne, ali različite vrste, A. radicina i A. petroselini. Dalja karakterizacija izolata A. petroselini poreklom iz Srbije, obavljena je sekvenciranjem različitih genskih segmenata uključujući ITS rDNK, kao i Alt a1 i EF1a gene. BLAST analiza pokazala je da su sekvence Alt a1 i EF1a gena najpouzdanije za razlikovanje A. petroselini od drugih blisko srodnih vrsta (25-27 odnosno 10-12 nukleotida razlike od izolata A. radicina). Sekvence ITS rDNK regiona bile su korisne, ali ne i potpuno informativne za identifikaciju izolata A. petroselini

Од отпада до биотерапеутика

Iako su bioterapeutici doveli do revolucionarnih promena u lečenju raka, dokazali svoju efikasnost u saniranju mikrobnih infekcija i lečenju ljudi sa retkim bolestima, zbog visoke cene nisu svima dostupni. Inovativni pristup gde otpad ulazi u sastav hranjivih podloga za gajenje bakterija bi mogao dovesti do smanjenja cene bioterapeutika. Fermentacijom na skali od 5 L je dobijeno nekoliko bioaktivnih prirodnih proizvoda, pri čemu je različit otpad bio izvor hranjivih materija za gajenje mikroorganizama proizvođača. Prodigiozin, sekundarni metabolit bakterije Serratia marcescens, dobijen je gajenjem S. marcescens u tečnoj podlozi sa homogenizovanim mesnim nareskom, a prinos prodigiozina je poboljšan čak 10 puta u poređenju sa standardnom podlogom.1 Kada je Pseudomonas sp. BK25H gajen u podlozi sa komponentama kuhinjskog otpada dobijen je odličan prinos piocijanina od 12,5 mg L-1. Slično, aktinomicin D i staurosporin, sekundarni metaboliti Streptomyces sp. BV365 i 410, su dobijeni gajenjem proizvođača u hranjivim podlogama sa komponentama poljoprivrednog otpada ili otpada dobijenog preradom lignoceluloze. S obzirom da neka od navedenih jedinjenja dostižu komercijalnu vrednost od 2.500,00 evra za 1 mg (https://www.sigmaaldrich.com/RS/en/product/sigma/s5921), dobijeni rezultati idu u prilog ideji da bi se otpadne materije mogle koristiti kao jeftine sirovine za proizvodnju vrednih hemikalija, uz istovremeno smanjenje njihove cene, pri čemu bi se i količina otpadnih tokova redukovala.Иако су биотерапеутици довели до револуционарних промена у лечењу рака, доказали своју ефикасност у санирању микробних инфекција и лечењу људи са ретким болестима, због високе цене нису свима доступни. Иновативни приступ где отпад улази у састав храњивих подлога за гајење бактерија би могао довести до смањења цене биотерапеутика. Ферментацијом на скали од 5 L је добијено неколико биоактивних природних производа, при чему је различит отпад био извор храњивих материја за гајење микроорганизама произвођача. Продигиозин, секундарни метаболит бактерије Serratia marcescens, добијен је гајењем S. marcescens у течној подлози са хомогенизованим месним нареском, а принос продигиозина је побољшан чак 10 пута у поређењу са стандардном подлогом.1 Када је Pseudomonas sp. BK25H гајен у подлози са компонентама кухињског отпада добијен је одличан принос пиоцијанина од 12,5 mg L-1. Слично, актиномицин Д и стауроспорин, секундарни метаболити Streptomyces sp. BV365 и 410, су добијени гајењем произвођача у храњивим подлогама са компонентама пољопривредног отпада или отпада добијеног прерадом лигноцелулозе. С обзиром да нека од наведених једињења достижу комерцијалну вредност од 2.500,00 евра за 1 mg (https://www.sigmaaldrich.com/RS/en/product/sigma/s5921), добијени резултати иду у прилог идеји да би се отпадне материје могле користити као јефтине сировине за производњу вредних хемикалија, уз истовремено смањење њихове цене, при чему би се и количина отпадних токова редуковала.Knjiga sažetaka: Treći Kongres biologa Srbije, Zlatibor, Srbija 21 - 25. 9. 2022

Prognostic significance of tympanosclerotic plaques localization and their morphological and histological characteristics for the outcome of surgical treatment

Background/Aim. Tympanosclerosis is a sequela of inflammation of the middle ear usually causing conductive hearing loss. The aim of the study was to determine the significance of tympanosclerotic plaques localization in the middle ear and their morphological and histological characteristics for surgical treatment outcome. Methods. This retrospective study included a total of 73 patients operated on for tympanosclerosis in the Clinic for Otorhinolaryngology, Military Medical Academy (MMA) in a period 1996-2010. The results of surgical treatment as well as the last audiometry findings were analyzed. considering follow-up periods of 6 months to 8 years. The patients were divided into 4 groups according to tympanosclerotic plaques localization in the middle ear and the classification suggested by Wieling and Kerr. The patients were also divided based on intraoperatively noticed morphological characteristics of tympanosclerotic plaques, while the third division was done as per histological findings. Surgical success was assessed using the suggestions of the Japan Otological Society. Results. The analyzed results showed the surgical success especially in the group II according to Wieling and Kerr, while histological findings had no impact on the outcome of the surgery. Conclusion. Surgical treatment has good results especially in patients with the mobile stapes. Results are satisfactory in other localizations, while various morphological and histological characteristics do not have impact on the surgery outcome

Verodostojnost prihoda i neto novčanih priliva kompanija u Republici Srbiji

U savremenim uslovima poslovanja kada se putem informacionih tehnologija podaci mogu na raznovrsne načine sortirati i obraditi javlja se mogućnost za prikazivanje iskrivljenih podataka o stvarnom poslovanju jedne kompanije. Manipulacija od strane menadžmenta sa finansijskim izveštajima je tema koja je uvek privlačila pažnju naučnih krugova. Svrha sprovedenog istraživanja je bio da ukaže na postojanje opravdane sumnje da kompanije u Republici Srbiji na neispravan način prikazuju svoje prihode i prilive novca iz poslovne aktivnosti u finansijskim izveštajima. Uzorak se sastojao od prikupljenih finansijskih izveštaja za 4031 kompaniju za period od 3. godine. Istraživanje je pokazalo da postoji mnogo veća sumnja u ispravnost prikazivanja priliva novca iz poslovnih aktivnosti nego u prikazivanju poslovnih prihoda. Iz ovog razloga zaključeno je da prilikom sastavljanja izveštaja o tokovima gotovine puno računovođa se ne pridržava pisanih zakonskih odredbi ili ne poseduje adekvatno znanje kako bi na ispravan način prikazali poslovanje kompanije

Fracture analysis of the pulley of a bucket wheel boom hoist system

© 2016, Polish Academy of Sciences Branch Lublin. All rights reserved. This paper presents the results of the pulley fracture analysis. Experimental investigations confirmed that the chemical composition and basic mechanical properties of the pulley material, except the impact energy at a temperature of –20°C, meet the requirements of the corresponding standard. The impact energy value at the temperature of –20°C is for ≈45% lower than the prescribed value which has considerable influence on the appearance of the brittle fracture, especially having in mind the fact that the bucket wheel excavators operate at low temperatures. Metallographic examinations as well as magnetic particle inspections indicated that initial cracks in the welded joints occurred during the manufacture of the pulleys. Characteristic levels of the rope load cycle are obtained by using in-house software which includes the dynamic effects of the resistance-to-excavation. The FEA results pointed out that in the representative load cases the combinations of the mean stress and the alternating stress in the pulley critical zone lie considerably below the limit line of the modified Goodman’s diagram. The conclusion, based on the presented results, is that the fracture of the pulley appeared as the result of the ‘manufacturing-in’ defects

Biološka i molekularna karakterizacija virusa mozaika krastavca poreklom iz lubenice u Srbiji

Investigation of the presence and distribution of Cucumber mosaic virus in watermelon crops in Serbia during 2012 revealed that the virus was present in five out of six surveyed localities. CMV was detected in 24.05% of total serologically tested samples using DAS-ELI­SA method and the virus was the most prevalent in the locality of Silbaš. During this investigation, Cucumber mosaic virus was present more often in mixed infections with ZYMV and/or WMV (12.66%), while the single infection was detected in lower percentage, 11.39%. Five CMV isolates were obtained by mechanical inoculations of N. glutinosa and two of them were selected for further biological characterization. Concerning type and severity of symptoms on test plants, the investigated isolates exhibited different phenotypic features. Molecular detection was performed by amplification of a fragment of 871 bp in all tested isolates, using the primer pair CMVCPfwd/CPrev that amplify the entire coat protein gene and part of 5' and 3' UTR regions. The affiliation of Serbian CMV isolates from watermelon to subgroup IA, the group that includes most of the isolates selected for phylogenetic analysis, was determined by sequence analysis of the complete CP gene and reconstruction of phylogenetic tree.Proučavanjem pojave i rasprostranjenosti virusa mozaika krastavca u usevu lubenice u Srbiji tokom 2012. godine, prisustvo virusa utvrđeno je u pet od šest pregledanih lokaliteta. Prisustvo virusa ustanovljeno je u 24,05% serološki testiranih uzoraka (DAS-ELISA), a najzastupljeniji je bio na lokalitetu Silbaš. Tokom ovih istraživanja virus mozaika krastavca češće je bio prisutan u mešanim infekcijama sa ZYMV i/ili WMV (12,66%), dok je prisustvo pojedinačne infekcije utvrđeno u nešto nižem procentu, 11,39%. Mehaničkim inokulacijama N. glutinosa, dobijeno je pet izolata, od kojih su dva odabrana za dalju biološku karakterizaciju. Na osnovu tipa i jačine simptoma na test-biljkama, utvrđena je fenotipska varijabilnost ispitivanih izolata. Molekularna detekcija obavljena je amplifikacijom fragmenta dužine 871 bp kod svih ispitivanih izolata korišćenjem para prajmera CMVCPfwd/CPrev, koji omogućavaju umnožavanje gena za protein omotača i deo 5' i 3' UTR regiona. Analizom sekvenci kompletnog gena za protein omotača i rekonstrukcijom filogenetskog stabla, utvrđena je pripadnost izolata CMV iz lubenice iz Srbije podgrupi IA, koja obuhvata većinu izolata odabranih za filogenetsku analizu