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Impact of Climate Change on Pavement Structural Performance
No full textFuture climate change and its influence on the performance of the road network is an issue that is
concerning more and more road authorities. The impact of climate change on road infrastructure can be twofold: extreme climatic events can cause infrastructure damage and traffic disruptions in a short period of time, while long-term climate change can jeopardize the durability and functionality of road infrastructure over a longer period and cause more intensive maintenance work. The objective of the paper was to review potential impact of the most relevant climatic parameters like temperature and precipitation, on the long-term performance of primarily flexible pavements, since they constitute vast majority of road networks in the region. The case study has shown that increase in temperature of 1 oC would result in flexible pavement life reduction between 6% and 10%, depending on pavement structure and traffic loading. The road infrastructure design in the future would require taking into account future climate changes and not only historical climate information. In particular, it will be necessary to adapt design criteria regarding temperature and return period of storm flows, as well as selection of component
materials and asphalt mixture design to make more rutting resistant mixtures
Photocatalytic efficiency of ZnCr-mixed metal oxides in correlation to reaction parameters
Get PDFVarious organic pollutants are discharged into the water from chemical, textile and
pharmaceutical industries every day. The photocatalytic wastewater treatment is an efficient,
cheap and eco-friendly process for the removal of organic toxic dyes, such as methylene blue,
which is one of the most common toxic dyes in wastewater. Photocatalysts ZnCr mixed
oxides were synthesized and thermally treated at 500 and 900 °C. Their efficiency in
photocatalytic degradation of methylene blue and the influence of the reaction parameters
were studied. High photocatalytic activity of both samples was observed, where the complete
decolorization (100%) and partial decolorization (45%) of the aqueous solution of methylene
blue were achieved after 6 hours for ZnCr 900 and ZnCr 500, respectively. In order to
determine the influence of the pH on the photocatalytic effieciency, the photodegradation
reactions were conducted using better performing photocatalyst at different pH values,
measuring the photodegradation efficiency at the same time intervals. The optimal pH
resulting in the most efficient photodegradation for ZnCr 900 photocatalyst was observed at
pH 12, which could be explained by the correlation with different textural and structural
properties of photocatalysts. The results showed that the obtained ZnCr mixed oxides are
highly efficient in the methylene blue photodegradation and have a great potential for the
application in the photocatalytic wastewater treatment processes
Elementi bilansa vodovodnih sistema - Metodologija i terminologija
Get PDFU domaćoj literaturi i praksi planiranja, projektovanja ieksploatacije vodovodnih sistema postoje različititermini i metodologije za obračun i prikazivanjekomponenti potrošnje vode za piće i drugih komponentivodnog bilansa u vodovodima. Za potrebevodoprivrednih analiza i planiranja, u praksi i legislativiRepbublike Srbije nije unificirana metodologija iterminologija određivanja potreba za vodom zavodosnabdevanje. U radu je dat predlog terminologije imetodologije koja na jasan i nedvosmislen načindefiniše pojedine komponente potrošnje i potreba zavodom. Analizirana je kompatibilnost predloženemetodologije sa podacima sa kojima obično raspolažuvodovodska preduzeća, kao i sa IWA metodologijombilansa u vodovodima
A Novel ANN Technique for Fast Prediction of Structural Behavior
Get PDFIn recent decades, different concepts of machine learning (ML) have found applications in solving many engineering problems. Less time consumption in performing analyses, better optimization of the quality-price ratio and maintaining high model accuracy are just some ML advantages compared to traditional modeling procedures. There are currently a significant number of pre-trained machine learning models based on classification or regression tasks. However, there is a tendency to improve them through the implementation of the transfer learning (TL) approach. This article proposes an upgrade of the existing, pre-trained artificial neural network (ANN) model for the evaluation of the ultimate compressive strength of square concrete-filled steel tubular (CFST) columns. The aim of the improved TL model is to adapt to the problem of predicting the axial capacity of rectangular CFST columns in a more optimal way. The attractiveness of the TL is reflected through the possibility of overcoming certain shortcomings of classical models. Quick adaptation to the problem with small modifications of the existing surrogate model, better overcoming of potential overfitting even with a small dataset, and improved convergence towards the required solutions are some of the advanced TL strategies. The robustness of the proposed model was demonstrated through verification with experimental solutions and validation with the Eurocode 4 (EC4) design code. The application of such innovative paradigms can also be ensured for other research fields in a similar manner
Projekat silosa gipsa u postrojenju za odsumporavanje dimnih gasova u termoelektrani Nikola Tesla A
Get PDFPostrojenje odsumporavanja dimnih gasova u Termoelektrani Nikola Tesla A (TENT A) u Srbiji,
predstavlja jedan od najznačajnijih projekata u domenu zaštite životne sredine na Balkanu,
namenjen stabilizaciji koncentracije gasova sa efektom staklene bašte i prevenciji negativnih
antropogenih uticaja na klimatski sistem. Građevinski fakultet Univerziteta u Beogradu
učestvovao je u izradi projektne dokumentacije ključnih objekata postrojenja odsumporavanja u
TENT A. U ovom radu prikazano je projektno rešenje i opisane konstrukcijske specifičnosti
noseće hibridne konstrukcije Silosa gipsa namenjen dopremi i skladištenju krečnjaka
Sanacija temelja i oslonca figure spomenika "Beogradski Pobednik"
Get PDFU radu je prikazana sanacija temelja spomenika "Beogradski Pobednik", koja je imala za cilj da
se zaustavi neravnomerno sleganje postojećeg temelja i dalje naginjanje vrha stuba spomenika u
stranu. Sanacija je izvršena izvođenjem bušenih šipova. U okviru rada prikazano je i spcifično
rešenje oslanjanja figure na vrhu stuba spomenika, dizajnirano tako da, uz zadovoljenje nosivosti
i stabilnosti, omogući brzu i efikasnu montažu
Intuitionistic Propositional Probability Logic
No full textWe give sound and complete axiomatization of a probabilistic extension of intuitionistic logic. Reasoning with probability operators, unlike other works on this topic, is also intuitionistic, that is, measure functions used for modeling probability operators are partial functions. Finally, we present a decision procedure for our logic which is a combination of linear programming and an intuitionistic tableaux method
Procena stanja temeljnih konstrukcija turbo-generatora blokova A1 i A2 termo elektrane „Nikola Tesla“
Get PDFU radu je prikazana metodologija koja je primenjena kod kontrolnih proračuna dva
armiranobetonska turbo-stola termoelektrane „Nikola Tesla“ u Obrenovcu. Proračuni su rađeni sa
ciljem utvrđivanja stanja konstrukcija nakon višedecenijske eksploatacije i procene mogućnosti
njihovog daljeg korišćenja. Opisan je način formiranja proračunskog modela sa naglaskom na što
preciznije modeliranje krutosti radi adekvatnog sagledavanja ponašanja pod dinamičkim
opterećenjem. Model je kalibrisan upotrebom merenih vrednosti parametara materijala i
registrovanih dinamičkih karakteristika u radnom režimu i pri isključenoj opremi
Kontrola ugiba prema Evrokodu 2
Get PDFU radu su diskutovani postupci za verifikaciju ugiba prema Evrokodu 2 (EN 1992-1-1:2004).
Nekoliko problema se javlja pri primeni indirektnog postupka zasnovanog na ograničavanju
odnosa raspon-statička visina. Osim što nisu svi inputi jednoznačno definisani, vrednosti
ključnih parametara usvojene pri izvođenju kriterijuma često ne odgovaraju stvarnim
konstrukcijama, te je proračun ugiba često neophodan. Najjednostavnija mogućnost za
proračun bazira se na interpolaciji između vrednosti ugiba određenog za element bez prslina i
za potpuno isprskao element, što je ekvivalentno bi-linearnom postupku CEB-a. Rigorozni
proračun koristi postupak numeričke integracije dugotrajnih krivina sračunatih u većem broju
preseka duž raspona, ali za njegovo sprovođenje nedostaju ključne instrukcije u nekim
slučajevima