Expert project analyses in the process of road maintenance management

Za potrebe učinkovitog gospodarenja održavanjem cestovne mreže neophodno je raspolagati s ažurnom informacijskom osnovom i odgovarajućim modelom za odlučivanje. U radu se daje prikaz metodološkog postupka za ekspertne projektne analize za radove na održavanju i poboljšanju cesta uz korišćenje Baze Cestovnih Podataka (BCP) i primjenu HDM-4 modela. Postupak je uspješno primjenjen i prihvaćen u apliciranju zahtjeva za financiranje radova na održavanju i poboljšanju cestovne mreže od strane međunarodnih financijskih institucija (Svjetska Banka, EIB i EBRD) tijekom 2012-e godine.An updated information system, and an appropriate decision making model, must be put in place for an efficient road maintenance management. A methodological procedure for expert project-level analyses of road maintenance and improvement activities, based on the Road Data Base (RDB) and the HDM-4 model, is presented in the paper. The procedure was successfully applied and accepted in 2012, in the scope of application for funding of road network maintenance and improvement by international financing institutions (World, Bank, EIB and EBRD)

Uticaj ponavljanog livenja na biokompatibilnost dentalnih legura zlata

Although highly noble Au alloys have been considered as biocompatible dental materials, little is known about whether recasting affects their biocompatibility. The aim of this work was to study the effect of repeated casting procedures on the microstructure and biocompatibilty of a noble Au dental alloy. The prepared samples of one- four- and eight times melted/cast Dentor S were used to study primary cutaneous irritation and sensibilization on experimental animals. The extract of the alloy prepared by conditioning the Dentor S samples in a cell culture medium was used to study the cytotoxicity on L929 cells. The elemental composition and surface changes of the alloy were examined by Energy Dispersive X-ray (EDX) analysis and optical microscopy, respectively. Our results showed that repeated casting decreased the biocompatibility of Dentor S, manifested as decreased metabolic and proliferative activities of L929 cells and that the effect correlated with the number of melting/casting procedures. However, neither sample of Dentor S caused irritation and sensibilization on experimental animals. EDX showed that recasting slightly increased the content of Au and Cu and slightly decreased the content of Pt, Pd and Zn. These changes correlated with the observations by optical microscopy. In conclusion, our results show that repeated casting of noble Au alloy changes its microstructure and decreases the biocompatibilty, suggesting that this procedure should be avoided in dental practice.Visoko plemenite legure su biokompatibilni materijali, ali je malo poznato da li ponovljena livenja legura utiču na njihovu biokompatibilnost. Cilj ovog rada je bio da se utvrdi efekat ponovljenog topljenja i livenja na mikrostrukturu i biokompatibilnost visoko plemenitih dentalnih legura zlata. Pripremjena je serija uzoraka od jednom, četiri i osam puta topljene i livene Dentor S legure za ispitivanje primarne iritacije kože i senzibilizacije na eksperimentalnim životinjama, kao i in vitro ispitivanje citotoksičnosti na L929 ćelijama. Hemijski sastav i promena površine legure ispitivana je EDX analizom i optičkim mikroskopom. Naši rezultati su ukazali da ponavljana livenja smanjuju biokompatibilnost Dentor S legure, koja se manifestuje smanjenjem metabolitičke i proliferativne aktivnosti L929 ćelija i da je efekat u korelaciji s brojem topljenja i livenja. Ni jedan uzorak Dentor S legure ne uzrokuje iritaciju i senzibilizaciju eksperimentalnih životinja. EDX analiza dokazuje da ponovna livenja blago povećavaju procenat Au i Cu i blago smanjuju procenat Pt, Pd i Zn. Ove promene su u korelaciji sa zapažanjima na optičkom mikroskopu. Autori zaključuju da ponovljena livenja visoko plemenitih legura zlata menjaju mikrostrukturu i smanjuju biokompatibilnost i preporučuju da se ova procedura izbegava u svakodnevnoj praksi

The Influence of Temperature Changes on Concrete Pavement

The paper deals with the influence of temperature changes on concrete pavement. Due to differences in temperature on the upper and the lower surface of a concrete slab, the bending stress is created, resulting in concrete slab deformation. During the process of heating, the difference in temperature between the upper and the lower surface of pavement is created as a result of heat conduction. The upper surface has a tendency to expand (tense), whereas the lower one does not alter its dimensions, which results in generating the bending stress. Concrete pavement is most commonly placed in zones with extremely heavy traffic load as well as at bus stops. The analysis was carried out at bus stops in the city of Novi Sad for three different types of slab thickness. The thickness of slabs was 20, 22 and 24 cm. The testing was conducted in the longitudinal and transverse direction of the concrete pavement, both in the middle and on the edge of a slab. During the analysis of results, a conclusion was drawn that the concrete slabs were of different dimensions and thickness, and that they were placed on different subgrade reactions. The maximum values of stress were recorded in the middle of a concrete slab, in slabs whose thickness amounted to 24 cm, while the minimum stresses were identified in slabs which were 20 cm thick. The paper presents the stresses of concrete slabs, caused by changes in temperature, which depend on the subgrade reaction and dimensions of concrete slabs

Modeling of Arterial Stiffness using Variations of Pulse Transit Time

In this paper, a finite element (FE) modeling is used to model effects of the arterial stiffness on the different signal patterns of the pulse transit time (PTT). Several different breathing patterns of the three subjects are measured with PTT signal and corresponding finite element model of the straight elastic artery is applied. The computational fluid-structure model provides arterial elastic behavior and fitting procedure was applied in order to estimate Young's module of stiffness of the artery. It was found that approximately same elastic Young's module can be fitted for specific subject with different breathing patterns which validate this methodology for possible noninvasive determination of the arterial stiffness

Preliminarna ispitivanja antibaktericidnog delovanja etarskih ulja na ekonomski značajne fitopatogene bakterije

Numerous scientific research studies all over the world have addressed the problem of agriculture in the 21st century as being particularly sensitive to climate change, which has caused phytopathogenic bacteria to spread. Therefore, there is a clear and urgent need to contain this kind of risk in agricultural production (both conventional and organic farming). The objective of this study was to determine the antibacterial activity of 30 essential oils (EOs) against three harmful plant pathogenic bacteria of agricultural importance, Erwinia amylovora, Xanthomonas campestris pv. campestris and Pseudomonas syringae pv. syringae. The study included in vitro testing, using an agar-diffusion assay. The EOs of Ceylon cinnamon (leaf and bark), oregano, clove bud and palmarosa revealed antibacterial activity against the test bacteria, and the maximum mean inhibition zone diameters of 35 mm was found against E. amylovora and X. campestris pv. campestris (highly sensitive reaction), while it was smaller in the case of P. syringae pv. syringae, from 18.25-26.25 mm (sensitive to very sensitive reaction). Maximum diameter of the zone of inhibition (35 mm) was obtained using basil and peppermint against E. amylovora, and rosemary, blue gum and camphor tree against X. campestris pv. campestris. Not a single EO inhibited P. syringae pv. syringae with the resulting total diameter zone of 35 mm, and this test bacteria was resultingly classified as the least susceptible bacterium of the three tested. EOs of lemongrass, aniseed, ylang ylang, silver fir, lemon, dwarf mountain pine, bay laurel and scots pine caused sensitive reaction of the tested bacteria. Peppermint, black cumin, Indian frankincense, bergamot orange, common juniper, bitter orange and neem produced variable reactions from total to weakly or no inhibition at all. Weakly activity was found in niaouli and Atlas cedar. Eastern red cedar, patchouli, Indian sandalwood and ginger caused no reaction of any of the test bacteria. The results offer a basis for further work based on in vivo testing for the purpose of developing ‘natural pesticides’ for control of phytopathogenic bacteria, thus giving a significant contribution to reducing yield losses in agriculture and sustainable development.Brojna naučna istraživanja širom sveta potvrđuju da je poljoprivreda u 21. veku posebno osetljiva na klimatske promene koje su uzrok širenja fitopatogenih bakterija. Stoga je jasna hitna potreba za ublažavanjem ovog rizika u poljoprivrednoj proizvodnji (u konvencionalnoj i organskoj poljoprivredi). Cilj ovog rada je određivanje antibakterijske aktivnosti 30 etarskih ulja prema tri ekonomski značajne fitopatogene bakterije, Erwinia amylovora, Xanthomonas campestris pv. campestris i Pseudomonas syringae pv. syringae. Istraživanja su vršena u in vitro uslovima, korišćenjem agar-difuzne metode. Etarska ulja pravog cimeta (od lista i kore), origana, zatim karanfilića i palmaroze, su pokazala antibakterijsku aktivnost prema testiranim sojevima bakterija, ostvarujući zone inhibicije maksimum prečnika 35 mm dobijene u slučaju E. amylovora i X. campestris pv. campestris (visoko osetljiva reakcija), a u slučaju P. syringae pv. syringae manju, od 18.25-26.25 mm (osetljiva do vrlo osetljiva reakcija). Maksimalni prečnik inhibicione zone (35 mm) je takođe dobijen primenom ulja bosiljka i pitome nane prema E. amylovora i ruzmarina, eukaliptusa i ravensare prema X. campestris pv. campestris. Kod P. syringae pv. syringae ni u jednom slučaju primene ulja nije postignut maksimalan prečnik inhibicije od 35 mm, na osnovu čega je ova bakterija svrstana kao slabije osetljiva. Etarska ulja limun trave, anisa, ilang-ilanga, evropske jele, limuna, planinskog bora, lovora i belog bora su rezultirala osetljivom reakcijom testiranih sojeva bakterija. Pitoma nana, čurukot, tamjan, begramot, kleka, gorka pomorandža i nim su izazvali varijabilnu reakciju, od potpune inhibicije, do slabe ili čak i bez inhibicije. Slaba aktivnost je ostvarena kod niaoulija i atlaskog kedra. Sve tri testirane bakterije nisu pokazale reakciju prema virdžinijskoj kleki, pačuliju, sandalovini i đumbiru. Rezultati dobijeni u ovom radu daju osnovu za dalja istraživanja in vivo, sa svrhom razvoja 'prirodnih pesticida' koji se mogu primeniti za suzbijanje fitopatogenih bakterija, čime se daje značajan doprinos u smanjenju gubitaka prinosa u poljoprivredi i održivom razvoju

Antimikrobna aktivnost novosintetisanog endodontskog nanomaterijala na bazi kalcijum-aluminata

Introduction Materials used for root canal obturation and root perforation are expected to have, in addition to preventing apical, lateral and coronary leakage, antimicrobial effects on microorganisms that are not accessible to chemomechanical instrumentation and intra-canal medications. The aim of this study was to evaluate the antimicrobial effect of a novel calcium aluminate-based endodontic nanostructured biomaterial (ALBO-MCCA) using agar diffusion test. Material and methods the two materials were tested in the study. The nanostructured calcium aluminate was synthesized by the hydrothermal sol-gel method from individual components of calcium aluminate (CaOxAl2 O3 ), calcite (CaCO3 ) and barium sulfate (BaSO4 ) as radiocontrast agent in the ratio of 2:2:1 according to V. Jokanovic's recipe. The other used material was calcium silicate MTA Angelus (Londrina, Brazil). The antimicrobial effect was assessed using agar diffusion test. Standard strains of Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, cultured on blood Mueller-Hinton agar and Candida albicans cultivated on Sabouraud Dextrose Agar, were used as test microorganisms. Results the best antimicrobial effect after 24 h both materials showed against S. aureus. The mean values of the growth inhibition zone for ALBO MCCA were 5.7 ± 0.25 mm and MTA 6.2 ± 0.4 mm. The ALBO MCCA material showed slightly stronger antibacterial effect against E. coli compared to MTA (p lt 0.05), whereas none of the materials showed antibacterial effect against E. faecalis. Conclusion the ALBO MCCA material showed certain antibacterial effect on Escherichia coli, Staphylococcus aureus and Candida albicans that was comparable to antibacterial effect of MTA.Uvod Od materijala koji se koriste za opturaciju kanala korena i perforacija na korenu se očekuje da pored sprečavanja apikalnog, lateralnog i koronarnog curenja, poseduju i antimikrobno delovanje na mikroorganizme, koji nisu dostupni hemomehaničkoj obradi i intrakanalnim medikamentima. Cilj ovog istraživanja je bio da se testom difuzije u agaru proceni antimikrobni efekat novog endodontskog nanostrukturnog biomaterijala na bazi kalcijum-aluminata (ALBO-MCCA). Materijal i metode U istraživanju su korišćena dva materijala. Nanostrukturni kalcijum-aluminat je sintetisan hidrotermalnom sol-gel metodom od pojedinačnih komponenata kalcijum-aluminata (CaO·Al2 O3 ), kalcita (CaCO3 ) i barijum-sulfata (BaSO4 ) kao rendgen-kontrastnog sredstva u odnosu 2 : 2 : 1 prema recepturi V. Jokanovića. Drugi korišćeni materijal je kalcijum-silikatni MTA Angelus (Londrina, Brazil). Antimikrobni efekat je ispitivan testom difuzije u agaru. Kao test mikroorganizmi korišćeni su standardni sojevi Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, koji su kultivisani na krvnom agaru MuellerHinton, dok je C. albicans kultivisana na agaru Sabouraud Dextrose. Rezultati Najbolji antimikrobni efekat nakon 24 h oba materijala su pokazala prema bakteriji S. aureus. Izmerene prosečne vrednosti zone inhibicije rasta iznosile su kod ALBO-MCCA (5,7 ± 0,25 mm), odnosno kod MTA (6,2 ± 0,4 mm). Materijal ALBO-MCCA je pokazao nešto veći antibakterijski efekat prema bakteriji E. coli u odnosu na MTA (p lt 0,05), dok prema bakteriji E. faecalis nijedan materijal nije ispoljio antibakterijski efekat. Zaključak Materijal ALBO-MCCA je ispoljio određeni antibakterijski efekat na bakterije Escherichia coli, Staphylococcus aureus i Candida albicans komparabilan sa antibakterijskim efektom MTA

A measurement of roughness as indicator of road network condition – case study Serbia

Prethodna istraživanja su utvrdila da je mjerenje uzdužne hrapavosti kolnika izraženo kroz međunarodni indeks hrapavosti (International Roughness Index - IRI) jedan od najvažnijih pokazatelja za ukupnu ocjenu stanja cestovne mreže. U isto vrijeme IRI predstavlja ključni okidač za planiranje i primjenu različitih radova održavanja cesta kao što su sanacije ili rekonstrukcije kolnika. U radu se razmatraju postojeće metode za mjerenje hrapavosti kolnika i ocjenu stanja cestovne mreže u Republici Srbiji u ukupnoj dužini od 13 191,34 km.Earlier researches have established that the measurement of pavement longitudinal roughness expressed through International Roughness Index (IRI) is one of the most important indicators for overall evaluation of road network condition. At the same time IRI presents the key trigger for planning and applying the different road maintenance works like pavement rehabilitation or reconstruction. This paper examines the existing methods for measurement of pavement roughness and evaluation of the road network condition in the Republic of Serbia in total length of 13 191,34 km

Outputand perfomance based road maintenance contracting – case study Serbia

U radu se opisuju glavne karakteristike ugovora o održavanju i popravku cesta prema Output and Performance-Based Contracting for Roads (OPBC). Daje se pregled iskustava u primjeni takvih ugovora. Agencije za održavanje cesta koje su prihvatile OPBC pristup uštedjele su od 10 % do 40 % u cijeni radova u usporedbi s radovima ugovorenim po tradicionalnoj metodi. U razdoblju od 2004. do 2008. u Srbiji je bio primijenjen način ugovaranja prema Output Performance-based Maintenance Contract (OPBC) za pilot projekt u okviru Transport Rehabilitation Project-a financiranog od Svjetske banke. Prikazani su glavni rezultati i zaključci.The paper describes the main features of contract work for road maintenance and improvement under the Output and Performance-Based Contracting for Roads (OPBC). Experiences in the application of such contracts for the roads are reviewed. Road agencies that have adopted an OPBC approach have achieved cost savings from 10 % to 40 % compared to traditional method-based contracts. During the period 2004 ÷ 2008 Serbia implemented the Output Performance-based Maintenance Contract (OPBC) for routine road maintenance pilot project within Transport Rehabilitation Project financed by World Bank. The main results and conclusions are presented

Anatomski i funkcionalni faktori koji utiču na rezultate klasične hirurške procedure kod bolesnika sa regmatogenom ablacijom retine

Background/Aim. Rhegmatogenous retinal detachment is a potentially blinding condition of the posterior segment of the eye. Currently, the only treatment modality is surgery and surgical options include scleral buckling, pars plana vitrectomy and pneumoretinopexy. Many factors may influence the outcome of the surgery. Well defined indications are essential for achieving the best postoperative results. The aim of this study was to assess anatomical and functional outcome of treatment with scleral buckling for macula-off rhegmatogenous retinal detachments. Methods. This prospective, nonrandomized, interventional study included consecutive patients underwent scleral buckling for macula-off retinal detachment in the tertiary centre for vitreoretinal surgery. Results. A total of 168 consecutive patients (mean age 58.2 ± 13.9 years) were included in the study. Postoperatively, anatomical success was achieved in 152 (90.5%) of the patients. Parameters that influenced the anatomical success included the number of retinal breaks (p = 0.040), lens status (p = 0.041), preoperative proliferative vitreoretinopathy (p lt 0.001), patients' age (p = 0.049), and marginally, the presence of typical symptoms (p = 0.057). Duration of macular detachment, previous ocular trauma and refraction of the eye did not affect the anatomical result. Functional success was evaluated using the postoperative visual acuity and depended mainly on the duration of macular detachment prior the surgery. Visual acuity 0.4 or better was significantly more often achieved if duration of macular detachment was up to seven days (p lt 0.001). Refraction and patients' age did not influence the functional result. Conclusion. Scleral buckling is an efficient surgical procedure for treatment of patients with retinal detachment. Optimal results are achieved if operation is performed within the first seven days of duration of macular detachment.Uvod/Cilj. Regmatogena ablacija retine je oboljenje zadnjeg segmenta oka koje, ako se ne leči, može dovesti do slepila. Trenutno, jedini način lečenja je hirurški i opcije su klasična metoda (scleral buckling), pars plana vitrektomija i pneumoretinopeksija. Mnogi faktori mogu uticati na ishod operacije. Jasno definisane hirurške indikacije su ključne za postizanje dobrih postoperativnih rezultata. Cilj ove studije bio je da se procene faktori koji utiču na anatomski i funkcionalni ishod lečenja klasičnom metodom lečenja bolesnika sa regmatogenom ablacijom retine sa zahvaćenom makulom. Metode. U prospektivnu, nerandomizovanu, interventnu studiju bili su uključeni svi bolesnici operisani klasičnom metodom zbog ablacije retine sa zahvaćenom makulom, u tercijarnom centru za vitreoretinalnu hirurgiju. Rezultati. Ukupno 168 bolesnika (starosti 58,2 ± 13,9 godina) bilo je uključeno u studiju. Postoperativno, anatomski uspeh postignut je kod 152 (90,5%) bolesnika. Parametri koji su uticali na anatomski uspeh operacije bili: su broj ruptura retine (p = 0,040), status sočiva (p = 0,041), preoperativno prisustvo proliferativne vitreoretmopatije (p lt 0,001), starost (p = 0,049) i, granično, prisustvo tipičnih simptoma (p = 0,057). Dužina odvojenosti makule, ranije povrede oka i refrakcija oka nisu uticali na anatomski rezultat. Funkcionalni uspeh procenjivan je na osnovu postoperativne vidne oštrine i zavisio je uglavnom od preoperativne dužine trajanja odvojenosti makule. Vidnaoštrina 0,4 ili bolja bila je značajno češće postignuta ako je dužina trajanja odvojenosti makule bila do sedam dana (p lt 0,001). Refrakcija oka i životno doba bolesnika nisu uticali na funkcionalni ishod operacije. Zaključak. Klasična metoda scleral buckling je efikasna hirurška procedura za nekomplikovane slučajeve ablacije retine. Kada je makula zahvaćena, najbolji rezultati postižu se operacijom u toku prvih sedam dana od početka simptoma