The impact of the transition radius lower flange-web on local stress of monorail crane girder

Širokopojasne profile sa paralelnom konturom pojaseva, koji se danas dominantno koriste za izradu jednošinskih nosača dizalica, karakteriše relativno veliki radijus tranzicije konture pojasa u konturu rebra. Upravo zbog toga, uticaj pomenutog radijusa na naponsko stanje izazvano lokalnim savijanjem usled dejstva točkova dizaličnih kolica znatno je izraženiji kod širokopojasnih (IPB) profila, u odnosu na klasične I profile i srednje široke (IPE) profile. U radu su prezentirani rezultati numeričko-analitičkog i eksperimentalnog istraživanja lokalnih napona u zoni tranzicije donji pojas/rebro kod širokopojasnih profila. Utvrđeno je da se najveće vrednosti razmatranih napona javljaju na početku tranzicije konture, a ne u tački fiktivnog preseka konture rebra i donje konture donjeg pojasa, kako se navodi u relevantnoj literaturi i aktuelnoj tehničkoj regulativi (standard EN 15011:2014). Osim toga, rezultati istraživanja dokazuju da apsolutne vrednosti lokalnih napona na donjoj i gornjoj konturi nisu jednake.Wide flange I-beams with parallel flange contours, which are now predominantly used in production of monorail crane girders, are characterized by a relatively large radial transition between flange contour and rib contour. Therefore, the influence of the radius on the stress state, due to the local bending caused by the action of crane trolley wheels, is more pronounced in wide-flange I-beams (IPB) than in conventional (I) and mid-wide (IPE) I-beams. This paper presents the results of numerical-analytical and experimental research of local stresses in the lower flange-rib transition zone at wide flange I-beams. It was found that the highest values of the considered stresses occur at the start of the transition contour, and not in the fictive point of intersection of the rib contour and the upper contour of the lower flange, as stated in relevant literature and current technical regulations (standard SRPS EN 15011: 2014). In addition, research results show that the absolute values of local stresses on the lower and upper contours of the lower flange are not equal

Gas corrosion damage in Ti-stabilized interstitial free steel

The selective oxidation damage in the Ti-stabilized interstitial free steel during 60 s of recrystallization annealing at 820 °C under the different compositions of protective H2-N2 atmosphere at low dew point (–40 °C) was investigated using various experimental techniques. It was found that Mn, Al and Si oxide particles are the main products of external and internal oxidation. Increase of the H2 content in gas atmosphere favors external oxidation and leads to appearance of greater nonwetted surface areas.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

The influences of multiscale-sized second-phase particles on fracture behaviour of overaged 7000 alloys

To identify the most important parameters of multiscale microstructural features influencing the fracture modes and resistance to damage, detailed microstructural and fractographic analysis of overaged 7000 alloy plates are performed using the broken plane-strain fracture toughness, K-Ic, test specimens. The geometric characteristics of differently sized second-phase particles are changed by the compositional variations. It was found that the fracture process involves three main micromechanisms. The dominant fracture mode changes with alloy purity, leading to fracture toughness degradation. Quantitative description of fractures by profilometry confirmed that crack initiation and propagation is fostered by the coarse Fe- and Si-rich particles. (C) 2009 Elsevier B. V. All rights reservedMesomechanics 2009 Conference, Jun 24-26, 2009, Oxford, Englan

Exploring the impact of local load of trolley wheels on stress states of monorail hoist crane

Циљ истраживања је утврђивање тренутног стања по питању примене пракси менаџмента енергије у индустрији Србије, и на основу резултата, предлог начина за побољшање. Мотивација за овакву тему је притисак европске регулативе на примену мера за уштеду енергије, као и потреба за испуњавањем одредби једног од најзахтевнијих поглавља за приступање Европској унији, поглавља 27, које се односи на заштиту животне средине. Стандарди за систем менаџмента енергије, на којима се ово истраживање заснива, разматрају енергетску перформансу коју постиже организација. Један од најпознатијих представника ове врсте стандарда је ISO 50001. Iстраживањем је закључено да индустријски сектор „Прерађивачка индустрија“ има у свету највећи број сертификата за систем менаџмента енергије (75%). Ова анализа је коришћена како би се даље истраживање усмерило на наведени индустријски сектор. Коришћењем АХП методе као алата одлучивања, дефинисани су приоритети за побољшање менаџмента енергије међу секторима прерађивачке индустрије у Србији. Критеријуми који су коришћени су: 1) Промена у нивоу производње, 2) Учешће у извозу, 3) Емисије CO2 из употребе фосилних горива, 4) Учешће у укупном финалном коришћењу енергије, и 5) Сертификација ISO 50001 у Европи. АХП метода је коришћена као алат за идентификовање у којим секторима прерађивачке индустрије у Србији постоји највећа потреба и оправданост за побољшање менаџмента енергије, а добијени резултати се могу користити као улазни елементи за креирање енергетске политике и основа за поређење са другим државама. На основу резултата, за даљу анализу су изабрани сектори „Прехрамбена индустрија“ и „Производња производа од осталих неметалних минерала“. На овај начин је проширено подручје примене АХП методе на нове проблеме и дефинисани су до сада некоришћени критеријуми одлучивања у случају предметног проблема. Спроведена је анализа нивоа примене захтева за систем менаџмента енергије у приоритетним секторима прерађивачке индустрије у Србији, која показује да се ниво примене менаџмента енергије у Србији креће од 11,76% до 100%, средња вредност је 59,05%, а одступање од средње вредности је 25,90%. 53,85% организација има ниво примене захтева испод просека, док је проценат организација које се налазе изнад просека 46,15%. Потпуна примена захтева за систем менаџмента енергије је утврђена у само 5,8% испитаних организација. Организације углавном имају дефинисан енергетски профил, комуницирају о менаџменту енергије и разматрају енергетску перформансу током пројектовања. Међутим, документација система готово и да не постоји, самим тим нема ни енергетске политике, а преиспитивања система и примена побољшања су ретка, највише из финансијских разлога...The aim of this research is to determine the current status of the energy management application in Serbian industry, and, based on the results, to propose ways to improve the current situation. The motivation for the topic is increasing pressure on the European regulation on energy savings, as well as the need to meet the provisions of one of the most challenging chapters for accession to the European Union, Chapter 27, which relates to environmental protection. Standards for energy management system, on which this research is based, discusses energy performance achieved by the organization. ISO 50001 is one of the representatives of this kind of standards. The analysis showed that the industrial sector "Manufacturing" has the world's highest number of certificates for the energy management system (75%). Such an analysis directed research toward manufacturing industry in Serbia. By using AHP method as a decision tool, priorities for improving the energy management among the sectors of manufacturing industry in Serbia were structured. The criteria used are: 1) Change in the production level, 2) Participation in exports, 3) CO2 emissions from fossil fuel use, 4) Share in total final energy use, and 5) Certification ISO 50001 in Europe. The AHP method was used as a tool for identifying which sectors of manufacturing industry in Serbia have the greatest need for the energy management improvement. The results can be used as inputs for energy policy, as well as the basis for benchmarking with other countries. Based on the results, sectors „Food Industry“ and „Manufacture of other non-metallic minerals“ were chosen for further analysis in this research. In this way, the scope of the AHP application was expanded to new problems, and so far unused decision criteria for the decision problem were defined. An analysis of the implementation level of energy management system in priority sectors of the manufacturing industry in Serbia was conducted. Results show that the level of energy management implementation in Serbia ranges from 11.76% to 100%, with a mean of 59.05%, and standard deviation of 25.90%. 53.85% of organizations have an implementation level below average while the percentage of organizations that are above the average is 46.15%. Full implementation of energy management system was determined in only 5.8% of the surveyed organizations. Organizations usually have a defined energy profile, communicate about energy management topics, and energy performance is considered in the design. However, the documentation system almost does not exist, energy policy does not exist, a system review and improvements are rare, mostly for financial reasons. If we observe data on the full energy management system implementation, we can see that the level of energy management implementation in Serbia is within the limits specified by the study in Denmark, far from the Swedish average, but the results obtained for 90-100% implementation are very close to the results obtained in Turkey..

Gas Chromatography in Environmental Sciences and Evaluation of Bioremediation

Crude oil and its derivatives, as the key energy-generating substances and raw materials used for production, are very widely used in all domains of work and everyday life. With the advent of oil as a fuel, there was the most intense economic growth and it can be said that the entire modern civilization is based on the utilization of oil. However, rapid growth and development of civilization in the past two centuries with the mass use of fossil fuels has led to imbalances and distortions of natural processes. In spite of improvements in technology and equipment used for oil drilling, transport and processing by the petroleum industry, oil and oil derivatives represent a significant source of environmental contamination

Evaluations of some classes of the trigonometric moment integrals

Four classes of the trigonometric moment integrals are evaluated in closed form in a simple and unified manner by making use of the contour integration in conjunction with the Cauchy integral theorem. In all cases, the closed contour of the same shape is used and it is shown that the integrals are expressible only in terms of the Hurwitz zeta function and elementary functions. A number of interesting (known or new) special cases and consequences of the main results are also considered. (c) 2008 Elsevier Inc. All rights reserved

Some discrete Fourier transform pairs associated with the Lipschitz-Lerch Zeta function

It is shown that there exists a companion formula to Srivastavas formula for the Lipschitz-Lerch Zeta function [see H.M. Srivastava, Some formulas for the Bernoulli and Euler polynomials at rational arguments, Math. Proc. Cambridge Philos. Soc. 129 (2000) 77-84] and that together these two results form a discrete Fourier transform pair. This Fourier transform pair makes it possible for other (known or new) results involving the values of various Zeta functions at rational arguments to be easily recovered or deduced in a more general context and in a remarkably unified manner. (C) 2009 Elsevier Ltd. All rights reserved

Calculation methods' comparative analysis of monorail hoist crane local bending effects

Rezultati numeričko-eksperimentalnih istraživanja problema lokalnog savijanja, obavljenih na klasičnim i srednje širokim I profilima, predstavljali su osnovu za donošenje aktuelnog standarda (EN 15011:2014) koji propisuje postupak proračuna lokalnih napona izazvanih dejstvom točkova kolica. S obzirom na činjenicu da se za izradu glavnih nosača jednošinskih transportnih sistema danas dominantno koriste širokopojasni IPB (HE-A, HE-B) profili, u radu su prezentirani rezultati proračuna lokalnih napona izazvanih dejstvom točkova kolica na pojas profila HE-A, primenom metoda i postupaka relevantnih istraživača, postupka koji propisuje standard EN 15011, kao i rezultati proračuna primenom metode konačnih elemenata. Na osnovu uporedne analize rezultata uočeno je da u zoni tranzicije donji pojas/rebro podužni lokalni naponi na donjoj konturi pojasa, određeni primenom navedenog standarda imaju zatežući karakter, dok sve ostale metode, uključujući i metodu konačnih elemenata, daju pritiskujući karakter razmatranih napona. Osim toga, svi navedeni postupci, izuzev metode konačnih elemenata, usvajaju pretpostavku da su na gornjoj i donjoj konturi opterećenog pojasa apsolutne vrednosti napona izazvanih lokalnim savijanjem jednake, što nema fizičkog opravdanja. Imajući u vidu činjenicu da identifikacija napona izazvanih lokalnim savijanjem pojasa predstavlja izuzetno važnu etapu dokazivanja čvrstoće jednošinskih nosača, zaključuje se da primena standarda EN 15011 ne daje pouzdane rezultate kada je reč o širokopojasnim profilima.The results of numerical and experimental researches of local bending problems, carried on classic and medium-wide I profiles, were a basis for the adoption of the current standards (EN 15011: 2014) which regulates the action of the local stress caused by the effect of cart wheels. Regarding the fact that IPB (HE-B) wide flange profiles are largely used for production of the main carriers of monorail transport systems, this paper presents the results of the action of the local stress caused by the effect of cart wheels on the HE-A flange profile, using the methods and procedures of relevant researchers, the procedures prescribed by the standard EN 15011 as well as the results of calculations using finite element method. It has been revealed, based on comparative analysis of the results, that in the transition zone low flange / rib longitudinal local stress on the lower contour flange, determined using the above mentioned standards have tightening characteristic, while all other methods, including finite element method, give the pressing nature of the considered voltage. In addition, all of these procedures, except for the finite element method, adopt the assumption that absolute value of voltage, caused by local bending on upper and lower contour of the loaded flange, are the same, and there is no physical justification. Bearing in mind the fact that stress identification, caused by the flange local bending, is an extremely important phase proving the strength of monorail beams, we may conclude that the application of standard EN 15011 does not provide reliable results when it comes to wide flange profiles

Spectrophotometric study of solution equilibria between Al3+ ion and L-histidine

Aluminium(III) ion and L-histidine (HHis) react in water solution to yield two mononuclear binary complexes [Al(HHis)]3+ and [Al(HHis)His] 2+. The over-all stability constants for these complexes were calculated by non-linearleast-squarestreatment of the spectrophotometric data and found to be: log β1,1,1 = 13.12 ± 0.04, log β1,2,1 = 20.9 ± 0.1, respectively. Indices refer to stoichiometric coefficients in complexation equilibrium: p Al + q His + r H → [AlpHisqHr]. The possible structures of the complexes in solution, are discussed.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Electronic structure of periodic curved surfaces -- topological band structure

Electronic band structure for electrons bound on periodic minimal surfaces is differential-geometrically formulated and numerically calculated. We focus on minimal surfaces because they are not only mathematically elegant (with the surface characterized completely in terms of "navels") but represent the topology of real systems such as zeolites and negative-curvature fullerene. The band structure turns out to be primarily determined by the topology of the surface, i.e., how the wavefunction interferes on a multiply-connected surface, so that the bands are little affected by the way in which we confine the electrons on the surface (thin-slab limit or zero thickness from the outset). Another curiosity is that different minimal surfaces connected by the Bonnet transformation (such as Schwarz's P- and D-surfaces) possess one-to-one correspondence in their band energies at Brillouin zone boundaries.Comment: 6 pages, 8 figures, eps files will be sent on request to [email protected]