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Računske velike vode u gornjem delu sliva reke Toplice
No full textPouzdana ocena računskih velikih voda je jedan od
najvažnijih i najkompleksnijih zadataka hidrologije,
posebno ukoliko se radi o hidrološki neizučenim
slivovima. Na tim slivovima se računske velike vode
određuju na osnovu računskih kiša i hidrološkog modela
epizoda. S obzirom da ne postoje opšteprihvaćene
smernice za proračun, definisanje hijetograma računskih
kiša i odabir hidrološkog modela predstavljaju subjektivne
odluke modelara. Međutim, ove odluke mogu značajno da
utiču na dobijene računske protoke. U ovom radu je
razmatran uticaj (1) širine bloka hijetograma računskih
kiša dobijenih metodom naizmeničnih blokova, i
(2) metode gubitaka u hidrološkom modelu na dobijene
računske velike vode na profilima u gornjem delu slive
reke Toplice. Za potrebe ovih analiza razvijen je semidistribuiran model primenom softverskog paketa HECHMS, dok su hijetogrami računskih kiša formirani na
osnovu HTP krivih određenih za glavnu meteorološku
stanicu Kopaonik. Dobijene računske velike vode
poređene su sa kvantilima istog povratnog perioda na
lokacijama tri hidrološke stanice na ovom delu sliva:
Magovo, Merćez i Donja Selova. Rezultati pokazuju da
dobijene računske velike vode mogu značajno da
odstupaju od kvantila, pri čemu na odstupanje mnogo više
utiče model gubitaka nego širina bloka hijetograma
računskih kiša. Odstupanja u velikim vodama kraćih
povratnih perioda (50 i 100 godina) pokazuju sličan šablon
ponašanja, koji se razlikuje od najekstremnijih 1000-
godišnjih velikih voda. Rezultati prikazani u ovom radu
ilustruju kompleksnost i neizvesnosti koje prate proračun
velikih voda na neizučenim slivovima, i ukazuju na
potrebu da opsežnim istraživanjima kako bi se postupak
ovih proračuna standardizovao
Corrigendum to “Integrating ‘nature’ in the water-energy-food nexus: Current perspectives and future directions”
No full textIntegrated approaches for managing natural resources are said to meet increasing demand for water, energy, and food, while maintaining the integrity of ecosystems, and ensuring equitable access to resources. The Water-Energy-Food (WEF) Nexus has been proposed as a cross-sectoral approach to manage trade-offs and exploit synergies that arise among these sectors. Although not initially included as a component of the Nexus, the role of nature in sustaining the water, energy, and food sectors and in regulating their interrelationships is increasingly recognised by Nexus researchers and practitioners. To converge existing approaches that integrate nature into the WEF Nexus and suggest a common framework, we – an interdisciplinary group of natural resources management researchers and systems thinkers from the European research network NEXUSNET COST Action – followed a collaborative process of knowledge creation combining literature review, elicitation of expert opinion and collaborative writing. Our results reveal a multiplicity of concepts utilised in the literature to represent, partially or fully, “nature” in the Nexus, such as “environment”, “ecosystems”, “ecosystem services”, “social-ecological systems”, and “biodiversity”. Disparity was also found in the role attributed to nature, represented by three key paradigms: (1) ecosystems as the fourth component of an expanded Nexus, i.e., the WEF-Ecosystems (WEFE) Nexus; (2) ecosystems as a foundational layer to the Nexus; and (3) the WEF Nexus as a central component of social-ecological systems (SES). By creating a hybrid approach that brings together the benefits of the respective paradigms, we present a forward-looking WEFE Nexus conceptualisation. This paradigm expands the mutual interlinkages among water, energy and food to the entirety of SES, thus acknowledging the social-ecological processes that are affected by and affect the WEF Nexus. The results of this collaborative research effort intend to provide researchers and stakeholders with means to better understand and ultimately manage Nexus issues towards a transformative change.Овај рад у часопису резултат је ангажовања чланова радне групе 2 у оквиру COST акције CA20138 “Network on Water-Energy-Food Nexus For a Low-Carbon Economy in Europe and Beyond” (NEXUSNET). Уз рад су достављене и званично објављене техничке исправке
Mitigating aquaplaning in motorway inflections zones
No full textAt the Faculty of Civil Engineering, University of Belgrade, research on aquaplaning in motorway
inflection zones is underway. Firstly, the research in concern is to produce methods of identifying inflection zones prone to aquaplaning, not only on the existing network, but also of eliminating them in the design stage. Therefore, several traditional and alternative superelevation methods in inflection zones, with accompanying design parameters, are analysed. With the defined geometrical parameters of the road (longitudinal and cross grades and superelevation), the stage is set for the calculation of water flow trajectories and water film depth (WFD). At the early stages of the research, it was noticed that the current formulas for calculating the WFD are not appropriate
for the motorway projects in Serbia and the new numerical methods are to be developed. In the inflection zones where aquaplaning risk could not be eliminated or reduced by using solely appropriate parameters of road geometry, the application of porous asphalt wearing course would be analysed. Outcomes of the research would be implemented into the updated Serbian polices in road design
Data–driven nonlinear finite element modelling of stub recycled aggregate concrete-filled steel tube columns under axial compression
No full textRecycled aggregate concrete–filled steel tubes are composite structural members consisting of steel tubes filled
with recycled aggregate concrete produced from crushed construction and demolition waste. The steel tube
confinement enhances the mechanical performance of the concrete, increasing load–bearing capacity and
ductility under axial compression. While experimental research on these sustainable members is growing,
high–fidelity 3D numerical models capable of accurately predicting their behaviour remain limited. This paper
presents an advanced framework for simulating the axial response of this type of structural member. The
workflow integrates Bayesian optimisation algorithm with a 3D nonlinear finite element model available in
commercial software, automated via Python scripting. A dataset of 209 experimental specimens is used to
calibrate a constitutive model for confined recycled concrete, essential for reliable column analysis. The proposed
model extends the Eurocode 2 stress–strain relationship in compression to capture the specific behaviour of
confined recycled aggregate concrete. Validation against experimental results shows good agreement in
load–displacement response and ultimate strength prediction. Derived from a wide experimental dataset, the
modelling strategy enables rapid and reliable assessment of column performance. Beyond its application to this
column type, the proposed framework illustrates the broader potential of integrating simulation, optimisation,
and data–driven modelling, offering a transferable methodology for diverse structural problems
Digital Twins of Urban Drainage Systems: innovative data assimilation algorithm for continuous state update
No full textUrban drainage systems (UDSs) are facing increasing challenges due to aging infrastructure and external factors, requiring innovative decision support solutions. Digital Twins (DT) of the real-world systems offer a promising decision-support tool for UDS management. These digital replicas, updated in real-time through sensor data integration, can assist with energy efficiency, resource allocation, and scenario analysis for contingency planning. DTs require up-to-date simulation model, and integration of the sensor data into the model is perceived as a critical component. This research introduces an innovative data assimilation method, utilizing Proportional-Integrative-Derivative (PID) controllers to update UDS model states based on sensor data. Proposed approach, tested with PySWMM on a synthetic dataset, demonstrates the potential for improving UDS performance and reducing uncertainty through continuous updates
Monitoring klizišta „iz fotelje“: od arhivskih aerosnimaka do satelitske radarske interferometrije
No full textTraditional landslide monitoring relies on field-based instrumental measurements, which often involve significant costs, time, and logistical support. With the development of remote sensing methods, the availability of spatial data (usually free of charge), and open-source software, the concept of so-called desk-based monitoring (“armchair monitoring”), i.e., observing changes without direct field visits, is becoming increasingly prevalent. This paper presents the possibilities and limitations of three complementary methods for such an approach: comparison of archival aerial imagery, analysis of differences in orthophotos, and satellite radar interferometry using phase-stable radar targets (Permanent Scatterer Interferometric Synthetic Aperture Radar, PSInSAR). Archival aerial imagery provides a multi-decade retrospective of landslide evolution through visual interpretation and photogrammetric analyses. However, they are often limited by variable image quality and the need for preprocessing, such as georeferencing. Orthophotos, as standard in modern geodetic databases, provide the basis for digital pixel- and object-based change detection, allowing quantification of surface changes. The most advanced approach in this set is PSInSAR, which uses a series of SAR images to detect very small displacements of terrain or objects over extended periods, with short intervals and millimetric precision. By combining these techniques, different temporal and spatial observation domains are obtained, enabling the identification of the initial landslide phases, detection of the active areas, and trend assessment. Desk-based monitoring should not be considered a replacement for field investigations but rather as an efficient methodological approach for landslide monitoring, especially under conditions of limited resources.predavanje po pozivu publikovano u celin
Međunarodna saradnja u oblasti vodnih resursa u okviru 50 godina rada Međuvladinog hidrološkog programa (IHP)
No full textUnesko (UNESCO) je specijalizovana agencija UN za obrazovanje, nauku i kulturu, osnovana 1945. godine, sa ciljem da se ostvari intelektualna i moralna solidarnost čovečanstva, kao sredstvo za izgradnju trajnog mira. U okviru Uneska, 1975. godine, nakon Međunarodne hidrološke dekade (IHD) (1964-1974), osnovan je Međuvladin hidrološki program (Intergovernmental Hydrological program - IHP). IHP je jedini međuvladin program u sistemu Ujedinjenih nacija i posvećen je unapređenju istraživanja i upravljanja vodnim resursima, kao i povezanim obrazovnim inicijativama i razvoju kapaciteta, koji su ključni za podsticanje održivog i integralnog upravljanja vodama. Rad IHP se odvija u vremenski ograničenim fazama, a trenutno je aktuelna deveta faza (IHP-IX) koja se odvija u periodu 2022-2029. godine koja je fokusirana na pomoć državama članicama u ostvarivanju ciljeva održivog razvoja, kroz identifikaciju ključnih prioritetnih oblasti u transdisciplinarnom istraživanju voda. U radu je prikazan istorijat IHP i aktivnosti pod njegovim okriljem u Republici Srbiji
Analytical approach to seismic behaviour assessment of RC frame structures with rubber jointed masonry infill
No full textInfilled structures are the most used type of structures in seismic-prone countries. Masonry infills are the most vulnerable part of these structures, even under medium-intensity earthquakes; hence, developing systems to prevent their failure to protect goods and human lives is crucial. Since current design codes are very advanced in reinforced concrete structures designs and there has been worldwide recognition of the importance of the infilled part of these structures, spotlight has been given to research and experimental and numerical analysis of behavior, seismic assessment and improvement of masonry infill – RC interaction. Recent experimental and numerical studies demonstrated that flexible joints in the infills or decoupling systems between the infill and the surrounding frame reduce the adverse effects of the frame-infill interaction on the ductility of the system. The main focus of this paper is to investigate the applicability and accuracy of a discrete macro element as a practical numerical tool for the design and assessment of RC masonry-infilled frames equipped with rubber joints alongside the frame. The model, implemented in OpenSees, can be represented by a simple equivalent mechanical scheme consisting of an articulated quadrilateral panel with a 1D diagonal link simulating the masonry shear deformability and eight 2D perimeter contact links governing the masonry axial and flexural responses and the infill-frame interaction.
The numerical analyses are conducted on a 1) full-scale RC frames with masonry infills subjected to pure in-plane and out-of-plane as well as sequential and simultaneous in-plane and out-of-plane loading [5] [6] and 2) full scale RC frames with masonry infills decoupling system INODIS [7] [8].
The experiment results and the numerical analysis show that these flexible joints aid in improving and balancing the structure’s bearing and ductility capacity and protect the masonry of pre-term damage. The comparisons between the numerical analyses and the experiments, presented in terms of displacement time histories and damage patterns, demonstrate that the macro-element can predict the complex non-linear dynamic response of the system with reasonable accuracy
Computational analysis of free-edge stresses in composite laminates using Abaqus
No full textThe free-edge effects are related to singular stress states at the interfaces between dissimilar layers in the vicinity of geometrical or mechanical discontinuities within the laminar composite. Stress concentration at free edges can further lead to delamination and a significant drop in stiffness, with fracture occurring at lower loads than expected. The paper deals with the computational (finite element) modeling of free-edge effects in cross-ply composite laminates. For this purpose, Abaqus software package has been used and two solid finite element types have been applied. Free-edge stress field of laminar composites under axial extension has been analyzed. Several numerical examples of cross-ply composites with various stacking sequences have been presented, and the results are compared against the existing analytical solutions based on the improved first-order shear deformation theory. Additionally, a parametric study has been conducted, focusing on the variation of τyz stresses through free edges as a function of plate thickness
Effect of process parameters on mechanical properties of cold metal transfer manufactured steel wall structures
No full textThis study investigates the effects of key process parameters on the thermal behaviour, geometric stability, mechanical performance, and microstructural evolution of unalloyed S355 structural steel wall structures fabricated via wire arc additive manufacturing (WAAM). Experiments were conducted using varying deposition trajectories, substrate preheating conditions, travel speeds, wire feed speeds, shielding gas compositions, and heat source configurations. Thermal imaging revealed that raster trajectories result in elevated temperatures and increased residual deformation, while sinuous trajectories provided improved surface quality and reduced distortion at the expense of reduced deposition efficiency. Shielding gas with higher CO₂ content enhanced arc energy and ductility but led to increased oxidation. Mechanical testing showed that optimised process parameters improved yield and ultimate tensile strength, though at the cost of ductility. Directional mechanical anisotropy was observed, with longitudinal specimens generally exhibiting superior performance compared to transverse ones. Microstructural characterisation using optical microscopy, X-ray diffraction (XRD), and electron backscatter diffraction (EBSD) confirmed that grain morphology and crystallographic texture are highly sensitive to thermal history. Excessive heat input contributed to grain coarsening and, in some cases, formation of bainitic or acicular ferrite, associated with diminished mechanical performance