Multidisciplinary analysis of steel plate of variable thickness in view of optimal design

The paper shows the indentification of deformational-stress state of partially loaded plates composed of two elements of different thicknesses. We analyzed metallurgical processes that characterize the technology of welding steel structures. The mathematical interpretation of the local stress state, through the developed software, enables an optimal design of geometric parameters of plate or supporting elements of construction according to the stress criteria. Comparative analysis of deflection and equivalent stress obtained by the analytical method and Finite elements method (FEM), using ANSYS 12 software package, the high agreement of results in terms of values and distribution trends is noticed. The application of the results of this paper is particularly important for the optimal design of steel girders

Ocena varijabilnosti telesnih mera srneće divljači

Despite the fact that a numerous factors have influence on variability of body dimensions in roe deer, research data on this topic are scarce. In order to obtain a necessary data, analysis of 6 body traits was carried out. Descriptive statistical parameters as well as coefficients of asymmetry kurtosis and quartiles were calculated. There are a noticable difference among obtained parameters between male and female roe deer. Among all body dimensions the most expressed variability has recorded in body weight, while body length had the smallest.Istraživanje varijabilnosti telesnih mera srneće divljači, uslovljeno je dvojakim razlozima. To je nedovoljno podataka, i raznolikost uticaja koji doprinose izraženijem ispoljavanju varijabilnosti. U cilju dobijanja potrebnih pokazatelja, obavljena je obrada za šest osobina kod ukupno 218 grla srneće divljači oba pola. Pored standardnih pokazatelja, izračunate su i vrednosti trećeg i četvrtog momenta za ocenu asimetrije i kurtoze, zatim kvartili Q.25,,Q.75 i interkvartilno rastojanje. Obrada raspoloživih podataka omogućava da se jasno uoče razlike u pojedinim pokazateljima uslovljenih polom. Najizraženije variranje mereno SD i CV je za telesne mase a najmanje za dužinu tela. Distribucija varijanata odstupa od normalne, sa nekoliko izuzetaka ona je asimetrična i više spljoštena. U celini posmatrano, najmanje variranje nalazi se u okvirima IKR, a najviše u donjoj četvrtini, tj. od minimuma do vrednosti Q.25. Kod sve tri grupe, u ovom delu je najveća zastupljenost, s tim da osobine kod kojih je i procenat najveć i su različite, za srne (dužina tela), za srndaće i zbirno (visina grebena)

Material characterization of the main steam gate valve made of X20CrMoV 12.1 steel after long term service

Martensitic steel X20CrMo12.1 has been extensively used within the last few decades as a material for tubing systems and pipelines in thermal power plants (TPP). Long term behavior of this steel is very well known and understood and because of that was found to be reliable material for prolonged service at elevated temperatures. It is well known that during operation TPP components are subject to microstructural changes that inevitably reflect decrease in their mechanical properties that lead to the loss of structural integrity and serviceability of component. This paper deals with the comprehensive investigation carried out on the main steam gate valve parent material of welded joint, as a part of main steam pipeline, after 170.000 h of service (545 degrees C and 19MPa). The obtained results showed that the microstructural degradation caused by long term operation had little effects on the hardness and strength of material, while the changes in impact toughness were observed. Comprehensive microstructural analysis included the examination of the microstructure on the surface and trough the wall thickness

Material characterization of the main steam gate valve made of X20CrMoV 12.1 steel after long term service

Martensitic steel X20CrMo12.1 has been extensively used within the last few decades as a material for tubing systems and pipelines in thermal power plants (TPP). Long term behavior of this steel is very well known and understood and because of that was found to be reliable material for prolonged service at elevated temperatures. It is well known that during operation TPP components are subject to microstructural changes that inevitably reflect decrease in their mechanical properties that lead to the loss of structural integrity and serviceability of component. This paper deals with the comprehensive investigation carried out on the main steam gate valve parent material of welded joint, as a part of main steam pipeline, after 170.000 h of service (545 degrees C and 19MPa). The obtained results showed that the microstructural degradation caused by long term operation had little effects on the hardness and strength of material, while the changes in impact toughness were observed. Comprehensive microstructural analysis included the examination of the microstructure on the surface and trough the wall thickness

Multidisciplinary analysis of steel plate of variable thickness in view of optimal design

The paper shows the indentification of deformational-stress state of partially loaded plates composed of two elements of different thicknesses. We analyzed metallurgical processes that characterize the technology of welding steel structures. The mathematical interpretation of the local stress state, through the developed software, enables an optimal design of geometric parameters of plate or supporting elements of construction according to the stress criteria. Comparative analysis of deflection and equivalent stress obtained by the analytical method and Finite elements method (FEM), using ANSYS 12 software package, the high agreement of results in terms of values and distribution trends is noticed. The application of the results of this paper is particularly important for the optimal design of steel girders

Plan integrisanog monitoringa kvaliteta zemljišta kao indikatora kvaliteta životne sredine u Novom Sadu

U radu je prikazan plan integisanog upravljanja životnom sredinom na primeru kontrole kvaliteta zemljišta u gradu Novom Sadu u Republici Srbiji. S obzirom da ima veoma povoljan geografski položaj, Novi Sad je grad gde se prepliću važni magistralni putevi, ima sve veći priliv stanovništva, kao i brzi razvoj industrije i poljoprivrede. Usled navedenih činjenica postoji i povećano zagađivanje vazduha, vode i zemljišta, kao i generisanje velike količine otpada. Pored parkova i devastiranih područja u okolini industrijskih zona, rasprostranjena poljoprivredna delatnost u prigradskim delovima, naročito je osetljiva na kvalitet zemljišta i obrnuto. U ovoj studiji analizirani su geografska pozicija i geomorfološke karakteristike područja grada, kao i vodeći ekološki problemi. Na osnovu datih činjenica predložen je integrisani monitoring jednog od indikatora kvaliteta životne sredine, kvalitet zemljišta. Predložena je mreža od ukupno 15 senzora za merenje pH vrednosti, vlage i temperature zemljišta na teritoriji grada. Podaci o kvalitetu zemljišta koji se na ovakav način dobijaju u realnom vremenu veoma značajni su za eliminisanje ili ublažavanje potencijalnih nepoželjnih posledica. Zahvaljujući brzom razvoju tehnologije primena senzorskih mreža sve više se koristi u modernim sistemima monitoringa i dostupna je za efikasno i ekonomski isplativo rešavanje problema zaštite životne sredine

Systems of Hess-Appel'rot Type and Zhukovskii Property

We start with a review of a class of systems with invariant relations, so called {\it systems of Hess--Appel'rot type} that generalizes the classical Hess--Appel'rot rigid body case. The systems of Hess-Appel'rot type carry an interesting combination of both integrable and non-integrable properties. Further, following integrable line, we study partial reductions and systems having what we call the {\it Zhukovskii property}: these are Hamiltonian systems with invariant relations, such that partially reduced systems are completely integrable. We prove that the Zhukovskii property is a quite general characteristic of systems of Hess-Appel'rote type. The partial reduction neglects the most interesting and challenging part of the dynamics of the systems of Hess-Appel'rot type - the non-integrable part, some analysis of which may be seen as a reconstruction problem. We show that an integrable system, the magnetic pendulum on the oriented Grassmannian $Gr^+(4,2)$ has natural interpretation within Zhukovskii property and it is equivalent to a partial reduction of certain system of Hess-Appel'rot type. We perform a classical and an algebro-geometric integration of the system, as an example of an isoholomorphic system. The paper presents a lot of examples of systems of Hess-Appel'rot type, giving an additional argument in favor of further study of this class of systems.Comment: 42 page

Anisotropic impurities in anisotropic superconductors

Physical properties of anisotropic superconductors like the critical temperature and others depend sensitively on the electron mean free path. The sensitivity to impurity scattering and the resulting anomalies are considered a characteristic feature of strongly anisotropic pairing. These anomalies are usually analyzed in terms of s-wave impurity scattering which leads to universal pair breaking effects depending on only two scattering parameters, the mean free path and the impurity cross section. We investigate here corrections coming from anisotropies in the scattering cross section, and find not only quantitative but also qualitative deviations from universal s-wave isotropic pairbreaking. The properties we study are the transition temperature, the density of states, quasiparticle bound states at impurities, and pinning of flux lines by impurities.Comment: 19 page

Distribution of chromium, nickel, copper and zinc in the Al Zintan area, northwestern Libya

Global population is growing rapidly. As a result, increasingly large areas are being settled and farmed. This devastates soils and causes pollution by heavy metals and other components. Heavy metals in the environment originate from both natural and anthropogenic sources. Natural sources generally include rock weathering and the propagation of heavy metals, such as Cr and Ni, from ultrabasic rocks. These are natural processes that generally do not threaten human health. Anthropogenic sources include industry and inappropriate disposal of waste in the environment. In such cases concentrations of heavy metals can be harmful to people and other living beings. Al Zintan is a city located in northwestern Libya, on a plateau mainly built up of Cretaceous sediments. Since the 1980’s, nomadic population has rapidly been settling this area. As a result, a former part of the desert was transformed and is used for farming. Soil sampling at Al Zintan was conducted in 2017, across a 2×2 km grid. A total of 143 samples were collected from depths of about 30 cm. The samples weighed 2 to 2.5 kg and generally comprised sand with a clay component. A Niton Xl3t goldd+ instrument was used for chemical analyses, based on which GIS heavy-metal distribution maps were generated. The distribution of Cr, Ni, Cu and Zn is discussed on the paper