THE SCALE AND EFFECT OF PUBLIC INVESTMENTS IN FLOOD CONTROL INFRASTRUCTURE IN SERBIA FROM 2009 TO 2021

Flood control structures play an important role in saving lives and property during floods, especially due to climate change issues. The construction, reconstruction, and rehabilitation of hydraulic structures are compliant with their maintenance and are performed periodically and preventively in order to achieve their required functional safety. However, over the years, investments in flood protection, i.e. the reduction of possible damage caused by the harmful effects of water, mostly implied investments in embankments. Investments in high dams are insufficient in terms of their importance, structure complexity, and failure risk

Utvrđivanje kriterijuma za izbor rešenja regulisanja rečnih tokova

People used moderate natural resources and obeyed the natural laws. Last Century of the II millennium constitutes a turning point in the relations, since it brought into question the harmony between people and the natural environment. The concept of „sustainable development“ is development which meets the needs of the present providing the ability of future generations to meet their own needs. The aim of this concept refers to the continuous improvement of quality of life and cannot be achieved if the community is not able to rationally and effectively use natural resources and ecological potential of the economy, providing an unbreakable link between economic prosperity, environmental protection and public interest. Water is an important natural resource. Engineering solutions for river training structures have a strong and long-lasting impact on the economy and society in general. Traditional structural solutions in river training works are focused on basic requirements as flood protection, littoral zone protection, river bed protection, providing the space for economic development. These solutions may lead to environmental degradation, i.e. alteration of physical-chemical and morphological characteristics of the natural components of the environment, decrease of diversity and biological productivity of natural and anthropogenic ecosystems, impacts on the ecological balance and quality of life. The main purpose of this thesis was to define a approach for the selection of hydraulic structures using multi criteria analysis, that would in addition to the basic water management requirements (flood protection, coastal protection, protection of the river bed, securing the space for economic development) provide the ecological development of rivers in accordance with the requirements of the „sustainable development“. This thesis elaborates on the application of multi criteria analysis method in selecting an appropriate alternative river training proposed solution for the section of the river course. Presented method is an aid to decision-making that helps stakeholders organize available information, think on the consequences, explore their own wishes and tolerances. Approach presented is based on the author's selection of sustainability criteria and identifies the best solution for the sustainable development of the river system, regarding to the environmental impact of proposed river training structural solution. In the case study section of the river in lower part of Carpathian Mountains is considered, for which three relevant intended alternative solutions are designed: riverbed with concrete lining, riverbed slope protection with vii gabions/gabion mattresses and natural (unregulated) riverbed. For alternative solutions respectable comparison the ELECTRE and PROMETHEE GAIA methods were applied, which allow comparison of different criteria unit measures. The main difference in the application of these methods is in defining the criteria weights, which in the method ELECTRE are exclusively subjective, while in a PROMETHEE GAIA method a respectable comparison of three scenarios of application of subjective, objective and integrated subjective and objective weights for criteria are given. For the analysis of the three scenarios defined alternatives, complete ranking of PROMETHEE GAIA method was performed using the software package Decision Lab 2000. In the case study, the final ranking of alternative solutions in both methods indicates that design of second structural solution is sustainable. MCA is not a tool providing the „right“ solution in a decision problem, since no such solution exists. The solution provided might be considered best only for the stakeholders who provided their values in the form of weighting factors, while other stakeholders’ values may indicate another alternative solution. Results obtained in the work and the conclusions derived have general character and can be applied in all areas of water management in the selection of optimal hydraulic constructive solutions

Adolescent acne: prevalence, risk factors and quality of life assessment

Akne pripadaju grupi od osam najčešćih bolesti u svetu a jedna su od tri najzastupljenijih kožnih bolesti. Po pravilu se prvi put javljaju u adolescenciji kod oba pola. Procenjena prevalencija adolescentnih akni varira od 41,7% do 94,9%. Rano prepoznavanje i lečenje akni je od ogromnog značaja jer može doprineti sprečavanju emotivnih i psihičkih poremećaja kod obolelih. Najvažniji faktori za pojavu akni su pozitivna porodična anamneza i hiperseboreja kože. Oprečni stavovi su i u domenu uticaja stresa, pušenja, nekvalitetnog sna i drugih navika, a intenzivno se proučava uticaj ekspozoma kao sveukupnog spoljnog štetnog dejstva na akne. Uticaj objektivno i subjektivno procenjene težine kliničke slike akni na umanjenje kvaliteta života je najčešće predmet populacionih istraživanja. Retke su studije koja se bave identifikovanjem faktora koji utiču na lošiji kvalitet života adolescenata sa aknama. Ciljevi. (1) Određivanje prevalencije različitih kliničkih oblika akni kod srednjoškolaca u Beogradu. (2) Utvrđivanje faktora rizika za nastanak akni kod adolescenata. (3) Procena kvaliteta života adolescenata sa aknama i identifikacija faktora koji doprinose lošijem kvalitetu života kod adolescenata sa aknama. (4) Analiza stavova adolescenata o prirodi bolesti, uzrocima nastanka, faktorima koji pogoršavaju bolest, kao i o mogućnostima lečenja. Metod. Sprovedena je studija preseka na stratifikovanom reprezentativnom uzorku adolescenata, učenika srednjih škola u Beogradu, tokom 3 konsekutivna meseca, od decembra 2012. do februara 2013. godine. Škole su odabrane metodom stratifikovanog slučajnog izbora. U cilju obezbeđivanja maksimalne participacije ispitanika, svi dostupni učenici, njih 2833, su bili usmeno obavešteni o vrsti i načinu istraživanja od strane anketara, a učestvovanje u istraživanju je bilo na dobrovoljnoj bazi. Podaci su prikupljeni anketom, a klinički pregled lica je obezbeđen od strane istovetnog anketara-dermatologa za sve učenike. Upitnik se sastojao iz nekoliko osnovnih delova: (1) osnovni demografski podaci , (2) podaci o aknama, (3) podaci o terapiji, (4) podaci o navikama (5) podaci o stavovima i znanju vezanom za akne. U cilju procene subjektivne percepcije stresa upotrebljena je skala percipiranog stresa - PSS (engl. Perceived stress scale). Kvalitet života je ispitivan upotrebom Kardifovog indeksa nesposobnosti u vezi akni (engl. Cardiff Acne Disability Index- CADI), a kvalitet života povezan sa zdravljem SF-36 anketom...and the third most common skin disease. The peak incidence is in adolescence in both gender, the prevalence varies between 41,7% do 94,9%. Considering the great impact of acne on emotional and mental health, the early diagnosis and treatment is essential in order to prevent further complications. The strongest risk factors for acne development are family history of acne and hyperseborrhoea. Conflicting results also refer to effects of stress, tobacco, quality of sleep and other personal habits on acne; the exposome and acne relation is currently under thorough investigation. The influence of objective and subjective acne severity on quality of life impairment is usually analyzed in cross-sectional studies. Still, the evaluation of specific predictive factors of acne disability is rarely performed. Objectives. (1) Prevalence of acne and acne severity grades among schoolchildren aged 14-18 years in Belgrade (2) Assessment of acneassociated risk factors (3) Analysis of quality of life in acne pupils and assessment of predictive factors of its impairment (4) Knowledge, beliefs and perceptions about acne in schoolchildren, including treatment seeking behavior. Method. We conducted cross-sectional study on representative sample of adolescents, high-school children in Belgrade, during 3 consecutive months (Dec 2012. until Feb 2013.). Schools were randomly selected. For maximal participation, the purpose of investigation was explained to 2833 available pupils, and their participation was voluntary. Collection of data was obtained through questionnaires, and the objective acne assessment was provided by single dermatologist-investigator for all participants. The questions were grouped in several parts:(1) basic demographic data, (2) information about acne (3) acne therapy, (4) data on personal behavior (5) knowledge about acne. Subjective assessment of perceived stress was measured using perceived stress scale (PSS). Disability due to acne was assessed with Cardif Acne Disabilty Index (CADI), and SF-36 generic questionnaire was used to assess the health related quality of life..

Antibacterial and Antibiofouling Activities of Carbon Polymerized Dots/Polyurethane and C60/Polyurethane Composite Films

The cost of treatment of antibiotic-resistant pathogens is on the level of tens of billions of dollars at the moment. It is of special interest to reduce or solve this problem using antimicrobial coatings, especially in hospitals or other healthcare facilities. The bacteria can transfer from medical staff or contaminated surfaces to patients. In this paper, we focused our attention on the antibacterial and antibiofouling activities of two types of photodynamic polyurethane composite films doped with carbon polymerized dots (CPDs) and fullerene C60. Detailed atomic force, electrostatic force and viscoelastic microscopy revealed topology, nanoelectrical and nanomechanical properties of used fillers and composites. A relationship between the electronic structure of the nanocarbon fillers and the antibacterial and antibiofouling activities of the composites was established. Thorough spectroscopic analysis of reactive oxygen species (ROS) generation was conducted for both composite films, and it was found that both of them were potent antibacterial agents against nosocomial bacteria (Klebsiela pneumoniae, Proteus mirabilis, Salmonela enterica, Enterococcus faecalis, Enterococcus epidermis and Pseudomonas aeruginosa). Antibiofouling testing of composite films indicated that the CPDs/PU composite films eradicated almost completely the biofilms of Pseudomonas aeruginosa and Staphylococcus aureus and about 50% of Escherichia coli biofilms

Synthesis and characterization of ceramic composite materials based on silicon-carbide and cordierite

Predmet ove doktorske disertacije je sinteza i karakterizacija kompozitnih keramičkih materijala na bazi silicijum-karbida i kordijerita. Silicijum-karbid, SiC, je kovalentno jedinjenje male gustine, velike tvrdoće, odlične termičke stabilnosti, dobre toplotne provodljivosti, dobre otpornosti prema termošoku. Ovakva svojstva omogućavaju njegovu brojnu primenu u raznim oblastima. Zbog kovalentne prirode veze, dobijanje guste SiC keramike je nemoguće bez dodatka aditiva. Dosadašnja ispitivanja su pokazala da se dodatkom smese oksida, kao aditiva, dobija gusta SiC keramika na temperaturama ispod 2100°C. Kordijerit, 2MgO 2Al2O3 5SiO2, poseduje odličnu termičku stabilnost, nizak koeficijent toplotnog širenja i dobru otpornost prema termošoku. U ovom radu kordijerit je dobijen iz dva izvora: iz spinela, MgAl2O4, i iz Mg-izmenjenog zeolita LTA a zatim je uz dodatak silicijum-karbida korišćen za sintezu kompozitnih materijala. Kompozitni materijali dobijeni su mehaničkim mešanjem SiC sa 30 i 50 mas.% kordijerita, dobijeno je četiri vrste kompozita. Posebna pažnja posvećena je proučavanju procesa sinterovanja u cilju dobijanja keramike sa poboljšanim fizičko-hemijskim svojstvima variranjem parametara sastav-temperaturapritisak. Praćen je uticaj sadržaja dodatog kordijerita na termostabilnost SiC/kordijeritnog kompozitnog materijala pošto poznavanje otpornosti vatrostalnih materijala prema termošoku određuje njihovu primenu. Dodatak grafita omogućio je formiranje pora tokom sinterovanja. Sadržaj dodatog grafita značajno utiče na poroznost i čvrstoću kompozitnog materijala pa je proučavan uticaj poroznosti na termostabilnost kompozitne keramike. U okviru istraživanja korišćene su nedestruktivnih metode karakterizacije: ultrazvučne metode za određivanje dinamičkog Jungovog modula elastičnosti i čvstoće tokom ispitivanja termošoka, kao i primena alata za analizu slike, Image Pro Plus program, radi određivanja stepena oštećenja uzoraka pre i u toku ispitivanja termostabilnosti. Uspostavljene su zavisnosti i predloženi modeli između izmerenih brzina prostiranja ultrazvučnih talasa, Jungovog modula elastičnosti, kao i stepena oštećenja uzoraka sa brojem ciklusa termošoka. Ustanovljeno je veoma dobro slaganje između rezultata predloženih modela posmatranih veličina sa brojem ciklusa termošoka. Ovakav pristup je doveo do razvoja modela za predviđanje smanjenja čvrstoće kompozitnih materijala usled termošoka na osnovu promena brzine prostiranja ultrazvučnih talasa kroz kompozitne materijale, kao i stepena oštećenja površine kompozitnih materijala. Takođe, ovaj pristup je iskorišćen radi razvijanja modela koji određuju kritični broj ciklusa, koje kompozitni materijali izdrže a da ne dođe do razaranja 50 % čeone površine usled izlaganja termošoku, na osnovu promena posmatranih parametara (brzina prostiranja ultrazvuka kroz materijal i stepen oštećenja površine)...The aims of this dissertation are synthesis and characterization of silicon-carbide and cordierite based ceramic composite materials. Silicon-carbide, SiC, is low density covalent compound with high hardness value, excellent thermal stability, high thermal conductivity and good thermal shock resistance. These properties of SiC allow numerous applications in different fields. Covalent bond of SiC precludes formation of high density SiC ceramics without additive. Previous investigations show that the combination of oxide mixture and SiC results in dense SiC ceramics at temperatures up to 2100°C. Cordierite, 2MgO 2Al2O3 5SiO2, has excellent thermal stability, low coefficient of thermal conductivity and good thermal shock resistance. In this dissertation cordierite was synthesized by using two sources: spinel, MgAl2O4, and Mg-exchanged zeolite LTA and then, the mechanical commixtures with SiC powder were prepared with the aim of obtaining four types of composite materials with 30 and 50 wt% of cordierite. Particular attention in this thesis was focused on sintering process. Processing parameters such are composition, temperature, and pressure were changed with the aim of synthesizing ceramics with good physical-chemical properties. Variation of cordierite content in composite materials was applied due to examine his impact on thermal stability of SiC-cordierite composite materials. Graphite, as pore former during sintering, was added to change porosity of SiC-cordierite composite materials. Since addition of graphite has strong influence on porosity and hardness, the influence of graphite additions, 10, 20, and 30 wt%, on thermal stability of SiC-cordierite composite materials was investigated. Nondestructive methods of characterization were applied: ultrasonic pulse velocity technique for determination of dynamic Young modulus of elasticity and strength during the thermal shock investigation as well as tools for image analyses Image pro Plus program for determination of degradation level before and during the thermal shock experiment. Correlations and models between measured ultrasonic velocity, Young modulus of elasticity and degree of degradation were established. Good agreement between the results of suggested models of analyzed parameters with number of thermal shock cycles were obtained. This approach leads to the models for prediction of strength degradation level of composite materials during the thermal shock based on changes of ultrasonic velocity through the composite materials and level of surface degradation. Based on this analysis, model for prediction of critical number of cycles, the number of cycles that composite materials exposed to thermal shock can withstand without surface degradation less than 50 %, was developed..

Comparative analysis of patch loading buckling resistances according to existing and new Eurocode

Summary: This paper compares the procedures for calculating steel plate girders according to thе current standards ЕN1993-1-5: 2006 [1] and the new version prEN1993-1-5: 2020, which is in the final stage of development [2]. There is a particular emphasis on problems of resistance to patch loading, the interaction between transverse force, bending moment and shear force, and the reduced stress method. The differences between the current standard and the new version prEN1993-1-5: 2020 [2] are illustrated using specific numerical examples

Животиње у погребном ритуалу на некрополи Батајница - Велика хумка

Skeletni ostaci životinja se naročito često nalaze u grobnim kontekstima iz ranog srednjeg veka na prostoru Karpatskog basena. Iako je tokom dosadašnjih arheoloških istraživanja na području Vojvodine otkriven relativno veliki broj nekropola iz razdoblja 10‒11. veka, gotovo su u potpunosti izostala proučavanja usmerena ka ispitivanju uloge životinja u ritualu sahranjivanja. Zato je cilj ovog rada rekonstrukcija pogrebnog rituala na nekropoli na Velikoj humci, i to analizom raspoloživih skeletnih ostataka životinja, odnosno da utvrde u kojoj meri se ovaj materijal može smatrati prilogom u hrani, ostatkom pogrebne gozbe (daće) ili simboličnim/žrtvenim prilozima. Takođe se ispituju značaj i zastupljenost vrsta životinja u okviru naznačenih kategorija. Na nekropoli Batajnica-Velika Humka otkriveno je 115 grobova, od čega su u 31 dokumentovani životinski ostaci.The paper presents results of the analysis of animal remains discovered during the excavations at the necropolis Velika humka near Batajnica dated to the second half of the 10th and the first half of the 11th century. The goal was to reconstruct the funerary rites, manifested in donating an entire animal or a part of it, as well as their symbolic background. At the necropolis, 115 graves were investigated, while animal remains originate from 31 of the graves

New scientific challenges - the possibilities of using selenium in poultry nutrition and impact on meat quality

Physiological stress is one of many concerns facing modern broiler production. In conditions when birds are exposed to stress, supplementation of selenium, which is a crucial glutathione peroxidase enzymatic cofactor, increases the antioxidant capacity of the animals and decreases the harmful effects of free radicals. Dietary selenium improves production performance and health of animals, and positively affects the immune system, the quality, selenium content and fatty acid composition of meat and eggs. There are several different forms of selenium, the most common dietary supplements being an inorganic form (sodium selenite) and anorganic form (selenomethionine). However, in recent years, new forms of selenium, such as a 2-hydroxy-4-methylselenobutanoic acid (HMSeBA) and nanoselenium, which have more bioavailability, bioefficacy, and low toxicity have been designed. In this short comparative overview discusses the effects of inorganic, organic and nanoforms of selenium on production results, glutathione peroxidase activity, meat quality and level of toxicity in poultry

The influence of tip sonication on structural and morphological properties of graphene

Although ultrasound is frequently used to disperse carbon nanomaterials in suitable solvents, the propagation of high-amplitude ultrasonic vibrations from the tip sonicator was found to be aggressive and has the potential to break down graphene sheets. Here, the effects of tip sonication time on structural and morphological properties of two types of graphene (graphene oxide and electrochemically exfoliated graphene) was investigated by UV-vis spectroscopy and Atomic Force Microscopy. It was found that the structural composition of the graphene was not affected by ultrasounds emitted from the tip sonicator even for the prolonged period of sonication (60 min). Microscopy analysis showed an increased portion of smaller graphene sheets in the sonicated samples for both types of graphene as a result of graphene sheet fragmentation caused by tip sonication