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NON-LINE ANALYSIS OF STIFFNESS IN COMPRESSION CONDITIONS
PublikacjaThe analyzes were aimed at demonstrating the influence of parameters describing the deformation of the structure on the uncertainty of critical force, and the impact of technological imperfections on stress uncertainty in compression conditions. In a linear buckling analysis, the problem is considered only for the initial, permanent state of the stiffness matrix. In the case of demonstrating the influence of initial deformations...
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Damage detection in a bolted lap joint using guided waves
PublikacjaThe paper presents the experimental investigation of guided waves application to the condition assessment of prestressed bolted connections and a concept of new quantitative indicator. The main goal of the research was the analysis of the influence of the contact conditions changes to the characteristics of a propagating disturbance. The experimental tests were carried out for a single bolted lap joint. The excitation and acquisition...
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Reliability assessment of an OVH HV power line truss transmission tower subjected to seismic loading
PublikacjaThe study focuses on the reliability of a transmission tower OS24 ON150 + 10, an element of an OVH HV power line, under seismic loading. In order to describe the seismic force, the real-life recording of the horizontal component of the El Centro earthquake was adopted. The amplitude and the period of this excitation are assumed random, their variation is described by Weibull distribution. The possible space state of the phenomenon...
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Basic sensitivity analysis of a telecommunication tower complementing standard reinforcement design process
PublikacjaThis paper presents straightforward sensitivity assessment of a telecommunication tower. The analysis is set toidentify the elements of the tower which may be reinforced with the greatest structural advantage. As current expertopin ions on structural redesign of similar structures due to a planned addition of extra loads are mainly based ondeterministic computations or engineering intuition,...
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Damaged plasticity model - seismic analysis of structure of the Petronas Twin Towers (Kuala Lumpur) in Malaysia
PublikacjaThe article presents numerical simulations for the modelling of seismic impact on the structure of Petronas Twin Towers (Kuala Lumpur) in Malaysia with application of two methods. The Response Spectrum method, in which a spectrum of the structure's responses to an earthquake's impact is generated and the Acceletogram (BETA) method, in which we generate dynamic load in the form of a diagram of the connection between acceleration...
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Crack propoagation in MgO-PSZ ceramic materials
PublikacjaThe properties of ceramic materials such as elevated hardness, high temperature capability, low coefficient of thermal expansion are of interest for rolling element materials. Widely used ceramic materials in engineering applications are silicon nitride, zirconia and alumina. The paper presents an experimental study of the fatigue life of MgO-PSZ ceramic material in lubricated contact with defined types of cracks. A ceramic angular...
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Numerical Modelling of Connections Between Stones in Foundations of Historical Buildings
PublikacjaThe aim of this paper is to analyse the behaviour of old building foundations composed of stones (the main load-bearing elements) and mortar, based on numerical analysis. Some basic aspects of historical foundations are briefly discussed, with an emphasis on their development, techniques, and material. The behaviour of a foundation subjected to the loads transmitted from the upper parts of the structure is described...
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Towards Understanding of Mechanics of Hernia Managed by Synthetic Mesh in Laparoscopic Operation: A Single Case Study
PublikacjaIn this paper a research towards understanding of mechanics of ventral hernia operated with the use of Physiomesh Open image in new window implant and SecureStrap Open image in new window staples is described. Experimental and numerical studies are conducted for that purpose. Experimental works cover uni-axial tension tests of the implant samples and of the implant-staples-tissue system. Also experiments on implant-staples-tissue...
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Concrete-filled FRP tubular members in marine and bridge structures
PublikacjaConcrete core of the concrete-filled tubes (CFTs) with circular cross-section is in the case of an axial compression subjected to a spatial state of compressive stresses. This state leads to enhancement in the concrete strength. The enhancement is utilized in Eurocode 4 design procedures for CFSTs (i.e. CFTs with tube made of steel). The structural design of CFFTs (i.e. CFTs with tube made of Fibre Reinforced Polymer - FRP) is...
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CHARACTERIZATION STUDY ON MECHANICAL PROPERTIES OF POLYESTER COATED FABRIC
PublikacjaThe scope of the paper is to determine the mechanical properties of the Precontraint 1302 polyester coated fabric under uniaxial and biaxial tensile tests. The results are compared for Precontraint 1302 fabric and other types of coated fabrics. The author applied an orthotropic model and a dense net model to reflect the polyester coated fabric performance under uniaxial and biaxial tensile tests. Material parameters are specified...
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PROBABILISTYCZNE ASPEKTY ZUŻYCIA SKOJARZEŃ CIERNYCH UKŁADÓW KORBOWO-TŁOKOWYCH NA PRZYKŁADZIE OKRĘTOWYCH SILNIKÓW SPALINOWYCH DWUSUWOWYCH NAPĘDU GŁÓWNEGO
PublikacjaW artykule przestawiono propozycję rozpatrywania zarówno obciążenia jak i zużywania ślizgowych skojarzeń ciernych (łożysk głównych i korbowych) układów korbowo-tłokowych silników spalinowych, zwłaszcza głównych, a także skojarzeń „tłok-tuleja” tych silników, jako procesów stochastycznych. Propozycję tę uzasadniono tym, że deterministyczne podejście do badania zarówno obciążenia jak i zużycia wspomnianych skojarzeń uniemożliwia...
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Porównanie działania transformatora symetryzującego (zygzak) z aktywnym energoelektronicznym symetryzatorem prądów fazowych linii niskiego napięcia
PublikacjaNa potrzeby planowania sieci niskiego napięcia operatorzy systemów dystrybucyjnych (OSD) zakładają symetryczne warunki obciążenia linii. Z roku na rok, rośnie liczba rozproszonych systemów fotowoltaicznych (PV) zainstalowanych w sieciach niskiego napięcia, których większość to małe jednofazowe systemy dachowe. Dodatkowo, do niesymetrii obciążenia przyczyniają się instalowane masowo pompy ciepła i ładowane jednofazowo samochody...
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Design and investigations of the ethanol microturbine
PublikacjaThe paper presents the results of the design analysis and experimental investigations of the microturbine set consisting of the microturbine with partial admission and permanent magnet generator. The microturbine was designed for operation with the vapour of ethanol as a working fluid. Microturbine unit was tested for different parameters of the working fluid and varying the electrical load. The examples and the comparison between...
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The Impact of Crushed Rock Spoil on Pitting Corrosion of Selected Stainless Steel
PublikacjaThe paper presents the results of the pitting resistance investigations of selected stainless steels in the chloride environment and the simultaneous impact of erosive factors using the cyclic polarization technique. Additionally, using electrochemical techniques, ie: electrochemical impedance spectroscopy (EIS) and measurement of corrosion potential, the behavior of the passive layer of selected stainless steels in the environment...
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Elderly persons professional activity - substantive issues and methodological challenges
PublikacjaPopulation ageing in Europe and mass withdrawal from professional activity leads to a number of adverse phenomena, such as increased public spending, reduced consumer demand and the growing problem of social exclusion. The study focuses on the problems of population ageing in Europe as well as on the feasible steps that may be taken with a view to professional activation of the elderly. The first part is concerned with the trends...
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The Many Faces of Enterococcus spp.—Commensal, Probiotic and Opportunistic Pathogen
PublikacjaEnterococcus spp. are Gram-positive, facultative, anaerobic cocci, which are found in the intestinal flora and, less frequently, in the vagina or mouth. Enterococcus faecalis and Enterococcus faecium are the most common species found in humans. As commensals, enterococci colonize the digestive system and participate in the modulation of the immune system in humans and animals. For many years reference enterococcal strains have...
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Comparison of AHP and Numerical Taxonomy Methods Based on Biogas Plant Location Analysis
PublikacjaThe paper presents a comparison of the multi-criteria Analytic Hierarchy Process (AHP) method and numerical taxonomy in biogas plant location selection. Biogas plants are sources that will significantly contribute to the implementation of the provisions of the energy and climate package for Poland by 2030. Increasing the share of energy produced from renewable sources, e.g. biogas plants, will increase the country’s energy security....
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Possible schemes of photoassociation processes in the KLi molecule with newly calculated potential energy curves
PublikacjaWe present four promising schemes for photoassociative formation of KLi molecule in its ground electronic state. Analysis is based on newly calculated adiabatic potentials supported by transition dipole moments and Franck-Condon factors.
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Ewolucja rachunkowości chińskiej na tle czynników kulturowych determinujących jej rozwój
PublikacjaRachunkowość jest złożonym systemem, którego kształt uwarunkowany jest wieloma czynnikami, także czynnikami środowiska, w którym realizuje swoje zadania. Wśród tych czynników ważne miejsce zajmuje kultura, właściwa dla danego kraju, która odbija swe piętno na celach i sposobie funkcjonowania systemu pomiaru i ujawnień rachunkowych. Dobitnym przykładem występowania korelacji pomiędzy kształtem rachunkowości a czynnikami kultury...
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Analysis and assessment of the acoustic emission suitability for determination of the energy states of a tribological system in the form of a four-ball tester friction node
PublikacjaThe present operating safety and cost reduction requirements of the compression ignition engines make it necessary to search for new methods of detecting their defects, e.g. by the analysis of acoustic emission signals coming from the slide bearings. The paper presents non-destructive measurements of acoustic emission (AE) in order to obtain information on the processes taking place in a tribological system under the continuously...
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Selection of main engines for hopper suction dredgers with the use oobability models
PublikacjaThis paper presents a new original method of selection of main engines for hopper suction dredgers with regard to probabilistic models. It was proposed to use the normal distribution to describe the operational loads of the main receivers. The principles for determination of parameters of load distribution and design power of the main engines were formulated. Lastly, the principles of selection of the size and number of main engines...
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Application, design and operation of constructed wetland systems: case studies of systems in the Gdańsk region, Poland
PublikacjaDifferences in operation result from physical, chemical and biological conditions, which directly influence transformations in the whole aquatic-matrix-plants environment. Depending on the quantity of inflowing organic matter load and the rate of biochemical processes, the contaminations could be removed or/and retuned in the system. From this point of view the facility should be designed and operated in such way that the highest...
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Elastic distortional buckling of thin-walled bars of closed quadratic cross-section
PublikacjaIn this study a thin-walled bar with closed quadratic cross-section is considered. The elastic stability of axially compressed bar related to the cross-section distortion is investigated. The governing differential equation is derived with aid of the principle of stationary total potential energy. The critical load for the simply supported bar is found in analytical form and it is compared with the FEM solution. Sufficient accuracy...
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Noninvasive method for rotor fault diagnosis in inverter fed induction motor drive
PublikacjaThis article presents a proposal, simulation and experimental results of a noninvasive rotor fault diagnosis method for the inverter fed induction motor drive. Comparing to reported methods the proposed one does not require any load, rotor brake, slip, mechanical or electrical system physical modification e.g. machine disassembly and can be applied regardless the rotor speed measurement or estimation method.
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Elastic distortional buckling of thin-walled bars of closed quadratic cross-section
PublikacjaIn this study a tin-walled bar with closed quadratic cross-section is considered. The elastic stability of axially compressed bar related to the cross-section distortion is investigated. The governing differential equatio is derived with aid of the principle of stationary potential energy. The critical load for simply supported bar is found in an analytical form and it is copared with the FEM solution. Sufficient accuracy of the...
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INDICES FOR ASSESSING POTENTIAL ENVIRONMENTAL HAZARD FROM FUTURE SHIP SCRAPPING PROCESS, DETERMINABLE IN SHIP DESIGN STAGE
PublikacjaThis paper shortly presents the issue of utilization of ships after their withdrawal from service. Information on number of floating units liquidated in previous years was presented. Hazards to the environment , health and life of workers employed in the Far East ship scrapping yards operating on the beaches, were indicated. Then, the most important rules which have to make the ship recycling process safe were referred to. This...
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Driving Performance Indicators of Electric Bus Driving Technique: Naturalistic Driving Data Multicriterial Analysis
PublikacjaThe issue of electric energy saving in public transport is becoming the key area of interest. By improving of driving techniques and the implementation of eco-driving, it is possible to save electric energy. Systems that help to decrease energy consumption and to reduce fuel emissions are becoming popular in vehicles powered by diesel engines. However, these methods have not yet gained popularity in electric vehicles. Therefore,...
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The effect of impacted third molars on second molar external root resorption, a cross-sectional cone beam computed tomography study
PublikacjaBackground: Third molars have the highest prevalence of impaction in teeth and can cause pathological damage on the adjacent second molars. This study aims to evaluate the effects of factors related to impacted third molars on external root resorption (ERR) in adjacent second molars using cone-beam computed tomography (CBCT). Material and Methods: In CBCTs, the effect of impacted third molars on the root surface of adjacent second...
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Influence of rhamnolipids and ionic cross-linking conditions on the mechanical properties of alginate hydrogels as a model bacterial biofilm
PublikacjaThe literature indicates the existence of a relationship between rhamnolipids and bacterial biofilm, as well as the ability of selected bacteria to produce rhamnolipids and alginate. However, the influence of biosurfactant molecules on the mechanical properties of biofilms are still not fully understood. The aim of this research is to determine the effect of rhamnolipids concentration, CaCl2 concentration, and ionic cross-linking...
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Dynamic analysis of the railway bridge span under moving loads
PublikacjaThe first part of this paper provides a review of the state of knowledge of the dynamic behaviour of railway bridges under moving loads. Particular attention is paid to developments in modelling railway bridge loading and dynamic vehicle-span (structure) interaction. The most important aspects determining the advancements in this area of knowledge are identified. The contemporary techniques for defining bridge span finite element...
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COMPUTER-AIDED CONSTRUCTION AT DESIGNING REINFORCED CONCRETE COLUMNS AS PER EC
PublikacjaThe article presents the author’s computer program for designing and dimensioning columns in reinforced concrete structures taking into account phenomena affecting their behaviour and information referring to design as per EC. The computer program was developed with the use of C++ programming language. The program guides the user through particular dimensioning stages: from introducing basic data such as dimensions, concrete...
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Sensorless Fault Detection of Induction Motor with Inverter Output Filter
PublikacjaThe paper presents the problem of monitoring and fault detection of a sensorless voltage inverter fed squirrel cage induction motor with LC filter. The detection is based on load torque estimation of the investigated torque transmission system. The load torque is calculated besides the computation of other variables that are mandatory for sensorless drive operation such as rotor flux and speed. The implemented LC filter smooths...
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Influence of meniscus shape in the cross sectional plane on the knee contact mechanics
PublikacjaWe present a three dimensional finite element analysis of stress distribution and menisci deformation in the human knee joint. The study is based on the Open Knee model with the geometry of the lateral meniscus which shows some degenerative disorders. The nonlinear analysis of the knee joint under compressive axial load is performed. We present results for intact knee, knee with partial and complete radial posterior meniscus root...
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Mechanical Properties of Twisted Carbon Nanotube Bundles with Carbon Linkers from Molecular Dynamics Simulations
PublikacjaThe manufacturing of high-modulus, high-strength fibers is of paramount importance for real-world, high-end applications. In this respect, carbon nanotubes represent the ideal candidates for realizing such fibers. However, their remarkable mechanical performance is difficult to bring up to the macroscale, due to the low load transfer within the fiber. A strategy to increase such load transfer is the introduction of chemical linkers...
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Will NILM Technology Replace Multi-Meter Telemetry Systems for Monitoring Electricity Consumption?
PublikacjaThe estimation of electric power utilization, its baseload, and its heating, light, ventilation, and air-conditioning (HVAC) power component, which represents a very large portion of electricity usage in commercial facilities, are important for energy consumption controls and planning. Non-intrusive load monitoring (NILM) is the analytical method used to monitor the energy and disaggregate total electrical usage into appliance-related...
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Tax Evasion, Tax Morale, and Trade Regulations: Company-Level Evidence from Poland
PublikacjaObjective: To investigate the determinants of the phenomenon of evading taxes among polish entrepreneurs. In particular, I examine such factors as tax administration satisfaction, tax morale, tax burden, and the influence of trade regulations. Research Design & Methods: A survey study conducted in 2017 in Poland among 454 enterprises. I used the zero-inflated negative binomial modelling technique to examine the impact of factors...
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Total impact of oxidative stress genes on cardiovascular events—a 7-year follow-up study
PublikacjaCardiovascular (CV) events are the number one cause of lifetime disability and deaths worldwide. It is well known that traditional risk factors do not fully correlate with clinical outcomes; therefore, searching for other markers that would explain CV events occurrence seems essential. Of importance, one of the main factors at the origin of CV events is oxidative stress, causing inflammation and atherosclerotic plaque instability....
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Seagrass vegetation and meiofauna enhance the bacterial abundance in the Baltic Sea sediments (Puck Bay)
PublikacjaThis study presents the first report on bacterial communities in the sediments of eelgrass (Zostera marina) meadows in the shallow southern Baltic Sea (Puck Bay). Total bacterial cell numbers (TBNs) and bacteria biomass (BBM) assessed with the use of epifluorescence microscope and Norland’s formula were compared between bare and vegetated sediments at two localities and in two sampling summer months. Significantly higher TBNs and...
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Antibiotic resistance in wastewater, does the context matter? Poland and Portugal as a case study
PublikacjaAntibiotic resistance has been considered a major human health threat that may endanger the success of medicine. Recent studies have unveiled worldwide asymmetries of antibiotic resistance occurrence, being factors as diverse as climate, socioeconomic, or antibiotic use possible drivers of such asymmetric distribution. In Europe, where clinical antibiotic resistance is surveyed for more than 20 years, the European Center for Disease...
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Application and mechanical properties of aluminium alloys
PublikacjaThe paper presents a short survey of the application and mechanical properties of aluminium alloys. This area of scientific research is still developing, the authors restricted it to about 30 papers. Numerical simulations of the aluminium bracket are also investigated. The authors propose a solution to increase the load capacity of aluminium brackets with application of the additional cover plates. This study is proposed as an...
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The Point Estimate Method in a Reticulated Shell Reliability Analysis
PublikacjaThe objective of this paper is to present an application of the point estimate method (PEM) to determine the probabilistic moments for engineering structures. Reliability analysis is illustrated by two examples: an estimation of the critical force in linear elastic buckling analysis and a reticulated shell limit load determinations. Calculations were also made using Monte Carlo method. It has been shown the practical usefulness...
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Failure Analysis of footbridge made of composite materials
PublikacjaFinite element method analysis of a pedestrian footbridge made of sandwich material is presented. The internal structure of the material is modelled as a structural shell assuming the Equivalent Single Layer approach (ESL). Two FEM commercial codes are employed. The response of the structure is studied in order to determine the load level that activates Hashin and Tsai-Wu failure criteria. Some practical aspects of designing footbridges...
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Analiza zmiennych objaśniających i rozbudowa modelu wyboru środka transportu
PublikacjaW artykule poddano analizie potrzebę uwzględnienia dodatkowych czynników wpływających na wybór środka transportu w prognozowaniu podróży. Przedstawiono dotychczasowe badania wpływu wybranych czynników na podział zadań przewozowych. W oparciu o wyniki krajowych Kompleksowych Badań Ruchu zostały wykonane analizy zależności udziału podróży transportem zbiorowym w obszarach zurbanizowanych od wybranych czynników zewnętrznych.
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How does institutional and natural social support shape the beliefs about psychological help among policemen?
PublikacjaEffectiveness of social support mechanisms results from interacting subjective factors (beliefs about help from others) and context (social network available). Organized institutional support and perception of natural support reduce barriers in obtaining psychological help.
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The applicability of low-cost PM10 sensors for atmospheric air quality monitoring
PublikacjaDescribed in this work are the results of field tests carried out in the Tricity Agglomeration between 01 April 2018 and 30 June 2018 in order to evaluate the usefulness of low-cost PM10 sensors in atmospheric air quality monitoring. The results were juxtaposed with the results obtained using reference methods. The results were validated based on the measurement uncertainty as described in...
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FORECASTING EXCHANGE RATES IN THE PROCESS OF THE ASSESSMENT OF CONSUMER RISK BANKRUPTCY IN CENTRAL EUROPE
PublikacjaThis paper focuses on the issue of forecasting the fluctuation of exchange rates as part of the early warning system against the risk of consumer bankruptcy. The author identified the main macroeconomic factors affecting the level of bankruptcies for households in Poland. The fluctuation of exchange rates, which directly affects the deterioration of the economic situation of borrowers who have opened credit accounts in a foreign...
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The Impact of Organizational Culture on Bicycle Commuting Frequency: The Research Based on Example of Three IT companies
PublikacjaThis chapter describes a study on work-related factors affecting employees’ decision on bicycle commuting. Employees’ transport choices are related to organizational culture. This chapter refers to E. Schein’s definition of organizational culture model. The study was made in order to determine the impact of specific levels of organizational culture on the transport behavior of employees. It is based on a survey performed in three...
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Selected problems of earth fault loop impedance testing in circuits fed from UPS
PublikacjaIn the paper a principle of earth fault loop impedance testing in low voltage systems has been presented. Selected factors, influencing accuracy of the testing, are indicated. A structure of UPS of VFI-type and the problem of impedance testing in circuits with such type of UPS are discussed.
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Mechanical properties of polyvinyl chloride-coated fabric under cyclic tests
PublikacjaThe aim of the present paper is to propose a method of laboratory tests necessary for the identification of mechanical properties of the coated fabric. The material parameters of the coated fabric AF 9032 are specified on the basis of the uniaxial and biaxial tensile tests. For the identification process, the techniques based on the least squares methods are used. Additionally, the uniaxial and biaxial cyclic tests are performed...
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3D buckling analysis of a truss with horizontal braces
PublikacjaThe present research is devoted to the study of out-of-plane buckling of a truss with horizontal braces. The truss is a model of real roof truss scaled by factor ¼. A linear buckling and a non-linear analysis with geometric and material nonlinearity were carried out. The truss buckling and limit load for different stiffnesses and number of braces are found. Numerical analysis are verified by experiment. Threshold bracing stiffness...