Methodology for statistical analysis of squat rail defects

This paper proposes a methodology for statistical analysis of data obtained by visual inspection of squat defects on the rail head. Rail inspection by visual observation, including measurement of the squat defect position and depth was performed in Pančevo Varoš railway station in 2017. The obtained data about the squat rail defect (defect type 227 according to the UIC 712) on the main tracks was analysed in this paper. The rail defect position was determined regarding the position of the nearest sleeper in the track. Statistical analysis of the occurrence of squat rail defect was conducted according to the performed visual inspection in the field. Statistical data processing was performed for tracks zones according to the vertical stiffness of rail support. Furthermore, the impact of traffic load, the type and the arrangement of sleepers on the appearance of the squat rail defect was considered

ФІНАНСОВОГО ПОТЕНЦІАЛУ ВІДНОВЛЕННЯ ПЛАТОСПРОМОЖНОСТІ ПІДПРИЄМСТВ МЕТАЛУРГІЙНОЇ ГАЛУЗІ УКРАЇНИ

As a result of component analysis of the concept of financial potential and finding the center of gravity by the method representants defined set of indicators to assess the financial potential of enterprises. Based on identified indicators was analyzed the financial potential of restoration of solvency of steel industry enterprises in Ukraine. The analysis revealed a low level of adequacy of financial resources to ensure the solvency, inability to  mobilize and inefficient distribution and use of financial resources, indicating a low level of financial potential of restoration of solvency of steel industry enterprises in Ukraine and high probability of financial insolvencyВ результате компонентного анализа понятия финансового потенциала и поиска репрезентантов методом центр тяжести определен набор показателей для оценки финансового потенциала предприятий. На основе определенных показателей проведен анализ финансового потенциала восстановления платежеспособности предприятий металлургической отрасли Украины.В результаті компонентного аналізу поняття фінансового потенціалу та пошуку репрезентантів методом центр тяжіння визначено набір показників для оцінки фінансового потенціалу підприємств. На основі визначених показників проведено аналіз фінансового потенціалу відновлення платоспроможності підприємств металургійної галузі України

Methodology for statistical analysis of squat rail defects

This paper proposes a methodology for statistical analysis of data obtained by visual inspection of squat defects on the rail head. Rail inspection by visual observation, including measurement of the squat defect position and depth was performed in Pančevo Varoš railway station in 2017. The obtained data about the squat rail defect (defect type 227 according to the UIC 712) on the main tracks was analysed in this paper. The rail defect position was determined regarding the position of the nearest sleeper in the track. Statistical analysis of the occurrence of squat rail defect was conducted according to the performed visual inspection in the field. Statistical data processing was performed for tracks zones according to the vertical stiffness of rail support. Furthermore, the impact of traffic load, the type and the arrangement of sleepers on the appearance of the squat rail defect was considered

The influence of lithium carbonate on the heat release during the hydration of Portland cement at the temperature 40°C

This work represents the stage of the author's research aimed at identifying the solutions for increasing the energy efficiency of the production of precast concrete and reinforced concrete products and structures in plant conditions due to reducing the temperature of heat treatment, or due to the reduction of duration of this technological process. The work provides results of the research of the influence of the admixture of lithium carbonate (Li2CO3) on the dynamics of hydration process of the binding systems on a cement basis in the conditions of the increased temperature (40°C). The research was performed using the method of isothermal calorimetry on the two various samples of the cement binder, conducted in various countries. The Li2CO3 admixture is accepted in dosages from 0.5% to 2.5%. The graphical dependence of the heat flow of the exothermic reaction of hydration on the used lithium carbonate dosage in the first days of curing of the samples is established and presented

Two-stage commercial evaluation of engineering systems production projects for high-rise buildings

The paper is devoted to the current and debatable problem of methodology of choosing the effective innovative enterprises for venture financing. A two-stage system of commercial innovation evaluation based on the UNIDO methodology is proposed. Engineering systems account for 25 to 40% of the cost of high-rise residential buildings. This proportion increases with the use of new construction technologies. Analysis of the construction market in Russia showed that the production of internal engineering systems elements based on innovative technologies has a growth trend. The production of simple elements is organized in small enterprises on the basis of new technologies. The most attractive for development is the use of venture financing of small innovative business. To improve the efficiency of these operations, the paper proposes a methodology for a two-stage evaluation of small business development projects. A two-stage system of commercial evaluation of innovative projects allows creating an information base for informed and coordinated decision-making on venture financing of enterprises that produce engineering systems elements for the construction business

Principles of Sustainable Infrastructure Formation in Research and Technology Development Centers Construction

The paper concerns the issue of infrastructure formation in research and technology development centers. It is established that the key point in the design and construction of such centers is providing the effective functioning of social infrastructure, which is a connecting link for the main structural elements of modern research and technology development centers. The grounds for the necessity of working out a unified pattern for designing research and technology development centers in compliance with the urban planning regulations and research and technology development priorities are given. An integrated model for working out a unified pattern of designing research and technology development centers is suggested. This model envisages creating a harmonized international standard that describes the basic principles of sustainable infrastructure formation in research and technology development centers construction. Based on the research results, the principles of sustainable infrastructure formation in research and technology development centers are set out and worded according to the goals of sustainable development. The authors also give grounds for the applicability of the principles formulated in this paper for the infrastructure assessment of research and technology development centers, both operating and under construction, which will make it possible to target the less-developed elements and draw up the plan of their improvement for further sustainable development. The authors also list emerging technologies to be developed and implemented for the efficient accomplishment of the research objectives

Upravljanje naponima u šinama na železničkim mostovima

This paper analyses the stresses in continuous welded rails on bridges including the aspect of fatigue of rail steel. Furthermore, it examines the possibility to avoid rail expansion joints, while simultaneously exploiting the permissible stress capacity of the rail profile 60E1. Accordingly, general application of permissible values of pressure and tensilestresses prescribed in the current European standards was critically analysed. Paper includes specific application aspects of the prescribed stress values for railway bridges in Serbia. General algorithm for reducing the stresses due to the vehicle/track/bridge interaction, which is presented in this paper, was developed by the authors. This algorithm includes all essential parameters of the bridge structure and railway superstructure, as well as the influence of climate conditions and railway route design.Ovaj rad analizira napone u kontiunualno zavarenim šinama na mostovima, uključujući aspekt zamora šinskog čelika. Pored toga, ispituje se mogućnost izostavljanja šinskih dilatacionih sprava, uz istovremeno iskorišćenje kapaciteta dozvoljenih napona za profil šine 60E1. U skladu sa tim, kritički je analizirana opšta primena dozvoljenih vrednosti napona pritiska i zatezanja koje su propisane u važećim evropskim standardima. Rad uključuje aspekte posebne primene propisanih vrednosti napona za železničke mostove u Srbiji. U radu je predstavljen opšti algoritam za smanjenje napona usled interakcije vozilo/kolosek/most, koji je razvijen od strane autora. Ovaj algoritam uključuje sve bitne parametre konstrukcije mosta i gornjeg stroja železničke pruge, kao i uticaj klimatskih uslova i projekta trase pruge

Solid-state nuclear magnetic resonance spectroscopy of cements

Cement is the ubiquitous material upon which modern civilisation is built, providing long-term strength, impermeability and durability for housing and infrastructure. The fundamental chemical interactions which control the structure and performance of cements have been the subject of intense research for decades, but the complex, crystallographically disordered nature of the key phases which form in hardened cements has raised difficulty in obtaining detailed information about local structure, reaction mechanisms and kinetics. Solid-state nuclear magnetic resonance (SS NMR)spectroscopy can resolve key atomic structural details within these materials and has emerged as a crucial tool in characterising cement structure and properties. This review provides a comprehensive overview of the application of multinuclear SS NMR spectroscopy to understand composition–structure–property relationships in cements. This includes anhydrous and hydrated phases in Portland cement, calcium aluminate cements, calcium sulfoaluminate cements, magnesia-based cements, alkali-activated and geopolymer cements and synthetic model systems. Advanced and multidimensional experiments probe 1 H, 13 C, 17 O, 19 F, 23 Na, 25 Mg, 27 Al, 29 Si, 31 P, 33 S, 35 Cl, 39 K and 43 Ca nuclei, to study atomic structure, phase evolution, nanostructural development, reaction mechanisms and kinetics. Thus, the mechanisms controlling the physical properties of cements can now be resolved and understood at an unprecedented and essential level of detail

СУХИЕ СТРОИТЕЛЬНЫЕ СМЕСИ ДЛЯ УСТРОЙСТВА ЗАЩИТНЫХ КОНСТРУКЦИЙ ОТ НЕЙТРОНОВ С ЭНЕРГИЕЙ 14,8 МэВ

Предмет исследования: бетон для устройства защитных конструкций от нейтронов с энергией 14,8 МэВ. При возведении защитных конструкций от ионизирующих излучений в зданиях объектов использования атомной энергии особое внимание уделяется качеству производства работ и оценке соответствия возведенных конструкций требованиям проектной документации. Цель исследования: получение необходимых данных для верификации программ нейтронно-физического расчета защитных характеристик бетонов различного химического состава. Материалы и методы: для достижения целей проведены расчетно-экспериментальные исследования с использованием генератора нейтронов с энергией 14,8 МэВ, комплекса спектрометрического и дозиметрического оборудования и расчетного программного комплекса ANISN. Исследования проводились для двух составов бетонов. Результаты: выявлена удовлетворительная сходимость расчетных и экспериментальных данных. Выводы: полученные результаты расчетно-экспериментальных исследований позволят разработать простые полуэмпирические методики расчета, которые могут быть использованы при проектировании составов бетонов с требуемой защитной эффективностью от нейтронов с энергией 14,8 МэВ и при контроле стабильности химического состава сухих бетонных смесей при их производстве и применении