Impact of Gravity on Fluid Mechanics Models

AbstractMathematical formulae which describe fluid mechanics models include the influence of gravity. In the literature and practice, when considering numerical hydraulic models, gravity is taken as constant value (“gravitational constant”). Actually, gravity is not constant and it is changing depending on mass distribution into the body of the Earth, mass density, altitude and topography (relief shape and mas density above the geoid). This paper is focused on the gravity influence on the different hydraulics models and fluid mechanic formulae in order to point out that gravity acceleration should not be treated routinely as “constant”

Management of environmental quality and Kostolac mine areas natural resources usage

Purpose – This paper aims to define and theoretically analyse the performance of modern methods investigated to speed up the recultivation process of degraded areas, and apply it into the mining basin, open pit mines, tailings and all other areas, which need environmental quality improvement. Design/methodology/approach – This paper presents methods of conservation and substitution of natural resources for the purpose of faster land recultivation (reclamation) in degraded coal mine areas. Two types of methods have been developed: forest slope recultivation and agricultural recultivation of flat landfills. Indicators of positive changes include: changes in chemical properties of tailings, increase in biogenic properties and changes in biodiversity. Findings – The research results show that the application of these methods, along with the holistic approach and adequate investment, can significantly contribute to the length of recovery process and accelerate it. Research limitations/implications – Mining basin Kostolac is used as a model test. The results can be applied on all mining basin, open pits and any degraded area. Originality/value – All results and conclusions were drawn, based on the original measurements and experiments. Stake holders, wanting to manage environmental quality after exploitation in mining basin, applying those methods, can find the value of this paper

Prirodne riznice vodnog resursa dunava - Đerdap 1, 2 i 3, u kontekstu održivosti i uticaja na životnu sredinu

U ovom referatu je predstavljen prirodni vodni potencijal reke Dunav na potezu kroz Srbiju i realizovani i planirani vidovi korišćenja tog resursa, tehnički, ekonomski i u kontekstu uticaja i potrebne zaštite životne sredine. Hidroenergetski i plovidbeni sistem „Đerdap 1”, kompleksan i višenamenski objekat, izgrađen je na 943. kilometru Dunava od ušća u Crno more. Konačan položaj glavnog objekta na profilu Sip Gura Vaii, određen je na osnovu obimnih topografskih, hidroloških, geoloških, hidrogeoloških, geomehaničkih i geotehničkih studijskih i istražnih radova. Ovako realizovan i izgrađen hidrotehnički objekat je obezbeđivao najoptimalnije iskorišćenje hidroenergetskog potencijala Dunava i uslov da se tokom gradnje plovidba ne obustavlja. HEPS „Đerdap 2” druga je zajednička hidroelektrana na Dunavu na granici sa Rumunijom. Izgrađena je na 863. km Dunava od ušća u Crno more na profilu Kusjak – Ostrovul Mare. Kao i HEPS „Đerdap 1” i ovaj sistem je kompleksan i višenamenski hidrotehnički objekat. Pored energetskog i plovidbenog ima veliki značaj za poljoprivredu, drumski i železnički saobraćaj. „Đerdap 3“ je specifično hidroenergetsko postrojenje u fazi projektovanja. U dnevnoj potrošnji električne energije postaje dva tzv. špica potrošnje – jutarnji i večernji. Ovaj drugi je u pogledu opterećenja do 2,5 puta veći od najmanjeg, koje nastaje posle 22 časa i traje do jutarnjih časova. PAHE „Đerdap 3“ obuhvata izgradnju ne samo hidroelektrane na obali Đerdapskog jezera nego i veće akumulacije vode na pogodnim mestima u dolinama rečica Pesače i Brodice. Nivo vode u tim akumulacijama je približno 400m viši od nivoa vode u Đerdapskom jezeru. Hidroelektrana Đerdap 3 je reverzibilno pumpno akumulaciono postrojenje, koje treba da bude izgrađeno na 1007 kilometru Dunava, četiri kilometara uzvodno od Lepenskog Vira i oko 100 km vazdušne linije od Beograda. Koncepcija rešenja sastoji se u tome da se voda zahvata iz Đerdapskog jezera sa kote 68, pumpa u gornje predviđene bazene "Pesača" i "Brodica", kada elektroenergetski sistem Srbije raspolaže viškom električne energije. Ako se dogovori saradnja sa stranim investitorima o realizaciji ovog projekta od strateškog značaja za našu državu, „Đerdap 3“ bi bila najveća reverzibilna hidroelektrana u Evropi

Renewable energy sources towards social challenges in sustainable development and low carbon economy

Low carbon economy, sustainable and holistic development is a challenge for all society. The imperative is to alleviate carbon emission, global warming effects and minimize cross-border environmental pollution. Developing countries follow the global policy and protocols by preparing their technically feasible renewable energy potential for investment and world emission trading market. This paper presents the current state of different renewable energy sources in Serbia, as well as opportunities for incorporating the world and European legislation, technology, knowledge, and investments in the energy sector of this Balkan country. Several case studies of initial investments in renewable energy sources are reported

On the Roman Concept of Natio

On the Roman Concept of Natio The aim of this paper is to examine the Roman concept of natio: what did the ancient Romans mean by it, in what sense did they use the term and how does the ancient Roman concept of natio differ from the modern concept of nation? The study is based on a corpus of Latin texts that belong to different periods and different genres. The earliest usages date back to the third century BC and the latest ones to the late second century AD. The texts that form the main source of data derive from the so-called Ciceronian age of Latin literature (81–43 BC). The study shows that the Roman concept of natio differed in many respects from the modern concept of nation. For the Romans, natio was primarily a collective term for a tribal community of foreigners who were tied together by the place of birth, but who were not organized into a politically recognized entity. The term was also used pejoratively to denigrate communities of people derided for their common values, interests and activities, as well as a term which referred to the place of origin of a product.   O rzymskim pojęciu natio Celem niniejszego artykułu jest analiza pojęcia natio w ujęciu starożytnych Rzymian. Spróbuję zastanowić się, jak rozumieli ten termin starożytni Rzymianie, jak go używali i czym różni się ich koncepcja natio od nowoczesnego rozumienia narodu? Swoje badanie opieram na korpusie tekstów łacińskich należących do różnych okresów i reprezentujących różne gatunki. Najstarsze użycia terminu są datowane na trzeci wiek przed narodzeniem Chrystusa, a najnowsze pochodzą z drugiego wieku naszej ery. Główny korpus tekstów powstał w tak zwanym cycerońskim okresie literatury łacińskiej (81–43 rok przed naszą erą). Analiza potwierdza istotną różnicę między rzymską koncepcją natio a nowoczesnym rozumieniem narodu. Dla starożytnych Rzymian natio był przede wszystkim terminem zbiorczym opisującym plemienną społeczność cudzoziemców powiązanych wspólnym miejscem urodzenia, ale nie zorganizowanych w politycznie uznaną całość. Termin był także używany w znaczeniu pejoratywnym, degradującym wspólnoty wyśmiewane z powodu ich wartości, zainteresowań i działań, jak również jako termin, który odnosił się do miejsca pochodzenia produktu

Windmills breakthrough in the governance of energetic landscapes

Mitigation measures of climate changes will have large-scale effects on the landscapes. Resource problems of energy are linked to the economic, environmental and social systems. Landscapes have energetic constraints, so mitigation measures of climate changes, divide landscapes into new categories. As environmental boom, proliferate wind farm projects, clusters of wind turbines, with audio-visual effects are under enquiry. Obsolete and outdated coal-fired backdrop, turns into new environmentalism enriched with top new sustainable technologies and digital discoveries. Placing windmills is conducted through initial project mapping and visualization, by locating appropriate topographic points and mixing criteria

Techno economic, environmentally and socially optimal energy efficient SHPP construction

Water resources engineering is facing with the complex problem when the construction of hydro power plants and its techno economic evaluations is charged with environmental and social problems. This paper is dealing with the selection of optimal small hydro power plants construction in the catchment area of Babinopoljska river, in Prokletije region in Montenegro. Total available potential, technically available and technically usable potential on the fifteen small hydro power plants profile and for catchments area in total was calculated, as well as average and installed discharge, net head, installed power and energy production for each constructed power plant. Cost benefit analyses for fifteen possible small hydro power plants is conducted, together with belonging environmental and social parameters. Delphi method was applied for the results quantification of Environmental and Social impact assessment study of the project. Optimal energy efficient construction solution was developed by mathematical multi criteria operational research method. Numerical introduction of environmental and social parameters in to techno economic analyses is novelty of this research. The result is the solution of three small hydro power plants, which belong to the concept of sustainable development of the region

Sustainability of chemical soil quality in Southern Morava river valley in correlation with the flooding

Land as the main edaphic factor, plays a very important role in the production of various field crops, fruit and vine crops. Its role is reflected in the fertility and productivity. Soil fertility includes content available nutrients, such as individual elements, pH and humus. The study of soil quality leads to conclusions about what the land is suitable for cultivation of what kind of culture. This paper presents the results of investigation of changes in soil quality in the South Morava river valley, in correlation with the floods. Different results of pH, humus, nitrogen, phosphorus and potassium, are obtain in the function of time, within the research conducted. Experiment was implemented two years ago, immediately after the flood and six months after the floods, which occurred in May 2014 in the region South Serbia. The methods that were used for the analysis of the soil are: colorimetric, photometric, potentiometric and spectrophotometry. Results show a high degree of sustainability of quality of land intended for the cultivation of field crops. The conclusion is that the soil relatively quickly regenerate their properties after floods

Sustainable management of Danube renewable resources in the region of Iron Gate Djerdap 1, 2 and 3 case study

Purpose - The purpose of this paper is to analyze sustainability of the constructed projects (Djerdap 1 and 2) and feasibility of the planned ones (Djerdap 3) on the river Danube in the region of Iron Gate, with multi-criteria focus on technical, economical and environmental parameters. Design/methodology/approach - The main objectives were achieved by using the methodology of a holistic multi-criteria approach. Electra method was applied. The design of the three projects on the international Danube River were analyzed, from technical, economical and environmental point of view, with the goal to manage a higher involvement of renewable resources. Findings - The results of the research imply that the most profitable technical solutions cannot reach its realization and construction if the environmental quality criteria are not fulfilled and included in the multi-criteria optimization model. At the same time, the most sustainable and environmentally friendly technical solutions, such as the renewable hydro pump storage scheme, cannot be realized without proper project management and investment. Research limitations/implications - The results and conclusions are valid for all the structures and projects of renewable resources, where there is a conflict to the environment. This research has implications to all decision-making processes focusing on holistic analyses of conflicted techno-economical and environmental parameters. Originality/value - The value of the paper and research is in proving the necessity of simultaneous analyses of technical, economical and environmental impacts on the projects. All the results of the research are beneficial for stakeholders who intend to invest in renewable hydro energy resources, in the function of sustainable development