Procter & Gamble (United Kingdom)
GraFar - Repository of the Faculty of Civil EngineeringNot a member yet
3934 research outputs found
Sort by
Estimation of Changes in Sediment Transport along the Free-Flowing Middle Danube River Reach
Get PDFThe subject of this study is an approximately 300 km long Middle Danube River reach that
spans from river kilometer (rkm) 1581 in Hungary to (rkm) 1255 in Serbia. The observed drying of
floodplains in Hungary some thirty years ago initiated the hydrological studies. However, problems
related to the navigation route maintenance of the Danube River and those in the water supply of
irrigation and drainage canal networks are now present in the whole free-flowing middle Danube
region. The study aims at investigating the correlation between the observed water level decrease
and recorded incision of the river bed at gauging stations and the indirect estimation of the long-term sediment transport along the sand-bed reach based on the surveillance cross-sections’ data
collected during regular monitoring surveys on the navigable Danube. It starts with hydrological
analyses of the 70-year-long time series of water level and discharge yearly data and continues
with morphological and correlation studies. It ends with the estimation of sediment transport. The
decreasing trend in water levels and the increasing trend in cross-sectional areas are persistent. There is a linear correlation between the two. Longitudinal changes in sediment transport indicate the existence of both degrading and aggrading riverbed reaches.Носиоци осталих ауторстава су уредници посебног, тематског броја Sediment Transpor
Mogućnosti primene DeNSE metode za sektorizaciju distributivnih mreža za redukciju gubitaka
Get PDFSektorizacija odnosno podela vodovodne mreže na osnovne zone bilansiranja (eng. District Meter Areas – DMAs) predstavlja najisplativiju i opšte prihvaćenu strategiju za kontrolu vodnog bilansa, pritisaka i smanjenje gubitaka u mreži. Izbor zona bilansiranja nije jednoznačan zbog čega je identifikacija njihovog optimalnog rasporeda u mreži izuzetno zahtevan zadatak, naročito u slučaju postojećih distributivnih sistema. Pored osnovnih kriterijuma (npr. veličina zona i dužina mreže) postupak sektorizacije treba da obuhvati i dodatne „lokalne“ kriterijume specifične za mrežu koja se razmatra kao što su minimalni broj dovoda, zadovoljenje protivpožarnog opterećenja itd. Metodologija za sektorizaciju primenjena u ovom radu zasnovana je na primeni indeksa uniformnosti mreže (eng. Uniformity Index) čime se omogućava identifikacija zona u mreži ujednačenih po potrošnji. Efikasnost, upotrebljivost i primena razvijene metodologije obezbeđena je kroz implementaciju sledećih celina u jedinstveni hidroinformacioni alat: 1) algoritm za automatsku sektorizaciju mreže na klastere, 2) efikasni model za hidrauličke simulacije i 3) višekriterijumska optimizacija. Osnovni kriterijumi za vrednovanje i izbor optimalnog rešenja su minimalna ulaganja u neophodne intervencije u mreži i očuvanje pouzdanosti sistema. Za poređenje stanja sistema pre i nakon sektorizacije usvojeni su sledeći indikatori performasi: 1) indeks sposobnosti adaptacije sistema (eng. Resilience Index) i 2) prosečan pritisak u zonama. Nakon identifikacije osnovnih zona bilansiranja, pažljivo odmerenim intervencijama na njihovim granicama u cilju dodatne redukcije pritiska se može uticati na potencijalno smanjenje gubitaka u mreži. Rezultati testiranja metodologije na realnom primeru distributivne mreže naseljenog mesta u Holandiji, sa primenom lokalnih kriterijuma, potvrđuju da metodologija može biti od značajne koristi u inženjerskoj praksi u procesu sektorizacije i izboru mera za smanjenje gubitaka
Long-term change in hydroclimatic regimes in catchments across Serbia
No full textThis study presents trend analyses in several catchments across Serbia. The trend analyses are preformed over series of precipitation, temperature and streamflows. These variables are represented by different indicators, such as the total annual precipitation, or maximum daily precipitation depth, temperature, and streamflow rate. The indicators are selected to represent different features of the catchment hydroclimatical regimes, such as mean or extreme conditions, or seasonality, and are all computed at the annual level. The
Mann-Kendall test for trend is applied over these annual series of indicators, and the series that result in the test null hypothesis rejection at 5% are considered to exhibit a statistically significant trend. The results of the Mann-Kendall test are complemented by the Sens’ slope estimator values, which indicate a sign of a trend. The trend analyses are further extended to joint considerations of concurrent occurrence of trends in climatical and hydrological indicators in the same catchment by conducting a correlation analysis. The objective of these analyses is to examine if the trends in climatical variables inevitably translate to trends in streamflow-related indicators, i.e., hydrological signatures, which is important in context of climate change and effective water resources management
Solving the Vehicle Routing Problem In the Open-Source Software ‘ODL Studio’
Get PDFTransport management is one of the most important logistical tasks, and the designing the optimal transport routes plays a major role in that process. Vehicle routing is primarily of interest to companies that organize the transportation of goods to end users, with the aim of minimizing the total cost of the routes. Being a well-known NP-hard problem, the theoretical background of the vehicle routing problem has been researched for many years and it has been the basis for the development of a large number of commercial software. However, affordable software solutions are lacking. Difficult access to high quality and reliable spatial data related to the road network is also a limitation. This paper discusses the possibilities of applying open-source software for solving the VRP. Open spatial data from a collaborative project of the virtual community was used as the basis for modeling the road network graph. The experiment was carried out on data on vehicles and customers of a certain retail chain and refers to the territory of Serbia
An Adaptive Section Discretization Scheme for the Nonlinear Dynamic Analysis of Steel Frames
Get PDFThe paper presents an adaptive section discretization scheme for the inelastic response analysis of structural members with cross sections that can be decomposed into rectangular and circular subdomains. Each subdomain can consist of a different material. As long as the largest strain in a subdomain does not exceed the specified trigger strain values, the subdomain contribution to the section response is determined by the numerically exact cubature rule for the subdomain. Once the largest strain reaches the trigger value for a subdomain, it is discretized with a fiber mesh and the numerical evaluation of its contribution to the section response is determined with the midpoint
integration rule. The fiber mesh with the midpoint integration rule remains in effect for the activated subdomain until the end of the response history. The paper applies the adaptive discretization scheme to the thin-walled sections common in metallic structures and investigates the effect of different trigger strain values on the accuracy and computational efficiency of the inelastic response analysis of wide-flange steel sections and multistory steel frames under static and dynamic excitations
Čelične konstrukcije u zgradarstvu: Opšta pravila za projektovanje prema SRPS EN standardima i nacionalnim prilozima
No full textWater distribution networks flushing planning: framework for optimization of implementation efficiency and cost
Get PDFIspiranje vodovodne mreže je osnovna aktivna fizička mera za čišćenje cevi vodovodne mreže sa ciljem održavanja i unapređenja kvaliteta vode za piće. Najčešće se primenjuju tradicionalna, odnosno konvencionalna, tehnika ispiranja i takozvana tehnika ispiranja u jednom pravcu. U ovom radu fokus je stavljen na tehniku ispiranja u jednom pravcu budući da se poslednjih decenija primarno ona koristi zbog određenih prednosti u odnosu na tradicionalnu tehniku. Ispiranje u jednom pravcu se može koristiti u formi reaktivnog odgovora nakon akcidenta sa kvalitetom vode (npr pojava zamućenja vode) ili kao deo protokola za održavanje kvaliteta pijaće vode u redovnim operativnim uslovima. Dobra praksa je pokazala da je neophodno imati plan ispiranja kojim se definiše sekvenca poteznih ispiranja za efikasno ispiranje određenog dela vodovodne mreže. Definisanje plana ispiranja se i dalje najčešće vrši „ručno“ uprkos činjenici da to predstavlja složen i dugotrajan proces. U ovom radu se identifikuju i analiziraju ključni kriterijumi za planiranje ispiranja: geometrijski, hidraulički i ekonomski. Predlaže se okvir za optimizaciju efikasnosti učinka i troškova implementacije, kojim se obezbeđuje bolja kontrola i ujednačenost efikasnosti ispiranja kao i realna procena troškova implementacije plana. Predstavljen je i razvijeni hidroinformatički alat (algoritam) za planiranje ispiranja i analizirani su rezultati primene na primeru jedne zone za ispiranje u gradu Amsterdamu u Holandiji.Water distribution network flushing is one of the basic active physical activities for pipe cleaning aiming to preserve and enhance the drinking water quality. Most frequently used techniques are traditional, or conventional, flushing and unidirectional flushing. In this paper, focus is placed on the unidirectional flushing as in past decades, well-equipped water utilities are preferring this technique due to the several advantages over traditional flushing. Unidirectional flushing can be applied in the form of the reactive response after the water quality accident (e.g. discoloration) or within a regular maintenance protocol, under regular operating conditions. Either way, good flushing practice has shown that a flushing plan is needed to define the sequence of the designed flushing operations aiming to allow for effective and efficient discoloration risk mitigation. Design of a flushing plan is still, commonly, a “manual” job, despite the fact that is complex and time-consuming task. Here key criteria for flushing planning are identified and analyzed: geometric, hydraulic and economic. A framework for efficiency and cost optimization is suggested, enabling better control and uniformity of the flushing effectiveness, and providing realistic estimates of the flushing cost. Developed hydroinformatic tool (algorithm) for flushing planning is presented and results of the application on the flushing zone in Amsterdam, Netherlands, are analyzed
CITYGML стандард за визуелизацију 3D модела градова
Get PDFУ раду је описан развој CITYGML стандарда за визуелизацију 3Д градских модела кроз историју. Приказане су основне карактеристике, промене и правац у којем ће се стандард даље развијати како би испратио нове технолошке револуције које се свакодневно дешавају
With the Chebyshev polynomials through geometric circulant matrices
Get PDFWe will present estimates for spectral norm bounds of the geometric circulant matrices whose entries are the Chebyshev polynomials of the first and the second kind. Some of the obtained results were verified by applying them to some known results on matrices involving various integer sequences, such as Fibonacci, Lucas, Pell and Jacobsthal integer sequences
Parametric Study of Additional Temperature Stresses in Continuously Welded Rails on Steel Truss Railway Bridges
Get PDFAdditional temperature stresses in continuously welded rails (CWRs) are caused by track/bridge interaction (TBI) due to thermal actions. Exceeding permissible stresses in CWRs on the bridge can lead to track buckling or rail cracking, compromising the safety of railway traffic. The main aim of the conducted study is to determine the effects of the key parameters such as rail cross-sectional area, track longitudinal resistance, bridge expansion length, and longitudinal stiffness of the fixed bridge support on the reduction of additional temperature stresses in CWRs on steel truss railway bridges. To quantify the effects of these parameters, two steel railway bridges with CWRs and the maximum expansion lengths according to UIC Code 774-3 were analyzed: (1) simply supported truss bridge with expansion length of 60 m and (2) continuous truss bridge with expansion lengths of 2 × 60 m. According to the obtained results, the track longitudinal resistance had the most significant impact on additional temperature stresses in CWRs, leading to their reduction of up to 72%. The bridge expansion length and the rail cross-sectional area led to reductions of up to 25% and up to 18%, respectively. Considering the deformation criteria of TBI, the longitudinal stiffness of the fixed bridge support had a minor effect on the reduction of additional temperature stresses in CWRs