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Search results for: DIFFRACTION OF BEAMS
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Variable-temperature X-ray diffraction study of structural parameters of NH---S hydrogen bonds in triethylammonium and pyridinium silanethiolates
PublicationHydrogen bonds in triethylammonium and pyridinium silanethiolate salts have been characterized by X-ray, FT–IR and NMR spectroscopies. DFT calculations reveal strongly asymmetric double-well minima at the potential energy curves of the studied compounds
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Short-range order structure and free volume distribution in liquid bismuth: X-ray diffraction and computer simulations studies
PublicationThe structure of liquid bismuth was studied by X-ray diffraction and computer simulation methods. The contraction of the atomic structure within the first coordination sphere in the temperature interval of 575- 1225 K is reported. The temperature dependencies of the coordination numbers and of the free volume are analysed. On the basis of the temperature dependencies of the free volume, the temperature dependencies of viscosity...
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Experimental Study of Dapped-End Beams Subjected to Inclined Load
PublicationThis paper presents the results of an experimental investigation of the reinforced concrete (RC) dapped-end beams loaded with inclined forces, compared to identical ones loaded with vertical forces only. Such a load may occur in, for example, Gerber's joints or in dapped-end beams supported on corbels, where the vertical gravitation force is additionally completed with horizontal forces caused by temperature differences, shrinking,...
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Ultrasonic diagnostics of concrete T-beams used in bridge structures
PublicationThis paper describes a method of ultrasonic diagnostics used for prefabricated concrete elements. The studies are focused on the applicability of nondestructive techniques based on impulse and wave packet induced elastic waves for the condition assessment of T-shaped bridge beams. Experimental tests were performed for the prestressed beam used for the superstructure of the viaduct on A1 highway near Toruń. In addition numerical...
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First natural transverse frequency of truncated cone and wedge beams
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Sensitivity analysis of beams and frames made of thin-walled members
PublicationMonografia dotyczy analizy wrażliwości w problemach statyki układów zbudowanych z prętów cienkościennych. Przedstawiono w niej nowe podejście do modelowania belek i ram z różnego rodzaju stężeniami ograniczającymi spaczenie przekroju poprzecznego, w przypadku skręcenia. Wprowadzono pojęcie superelementu belkowego i węzłowego. Przeprowadzono analizę statyczną belek i ram poddanych skręceniu lub skręceniu ze zginaniem, wzmocnionych...
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Free torsional vibration sensitivity analysis of thin walled beams.
PublicationW pracy przedstawiono analizę wrażliwości swobodnych drgań skrętnych bisymetrycznej , cienkościennej belki o otwartym przekroju poprzecznym, poddanej działaniu siły osiowej
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Static and sensitivity analysis of thin-walled beams and frames with stiffeners.
PublicationPraca zawiera tekst referatu wygłoszonego w Maastricht. Przedstawiono analizę statyczną oraz analizę wrażliwości belek i ram zbudowanych z cienkościennych elementów, poddanych skręcaniu lub zginaniu ze skręcaniem, z możliwością zastosowania różnego typu stężeń . Wykorzystano technikę superelementu do wyznaczenia macierzy sztywności węzła ramy i elementów ze stężeniami. Otrzymane wyniki dla modelu jednowymiarowego MES porównano...
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Adjoint approach sensitivity analysis of thin-walled beams and frames.
PublicationArtykuł omawia zastosowanie metody układów sprzężonych w numerycznej analizie wrażliwości belek i ram zbudowanych ze stalowych profili cienkościennych poddanych skręceniu lub skręceniu ze zginaniem. Przedstawiono wyniki analizy wrażliwości przemieszczeń i sił wewnętrznych na zmianę parametrów geometrycznych konstrukcji.
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Intercultural Challenges in Virtual Teams
Publication: Virtual teams are usually geographically dispersed and consist of members from different countries and cultures. They influences internal communication processes and can cause personal conflicts, misunderstandings or lack of trust. Intercultural diversity is also significant for goal setting and team effectiveness. The aim of this article is to check if virtual team members appreciate the cultural diversity or rather suffer from lack...
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Application of vibrational spectroscopy, thermal analyses and X-Ray diffraction in the rapid evaluation of the stability in solid-state of ranitidine, famotidine and cimetidine
PublicationThis paper reports the study on applicability of Fourier transform infrared (FTIR), near-infrared (NIR) and Raman spectroscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) for the estimation of the chemical stability and photostability of histamine H2-receptor antagonist substances. Ranitidine hydrochloride (RAN), famotidine (FAM) and cimetidine (CIM) were tested and differences in sensitivity were measured...
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Comparative X-ray diffraction and Mössbauer spectroscopy studies of BiFeO3 ceramics prepared by conventional solid-state reaction and mechanical activation
PublicationThe aim of this work was to prepare BiFeO3 by modified solid-state sintering and mechanical activation processes and to investigate the structure and hyperfine interactions of the material. X-ray diffraction and Mössbauer spectroscopy were applied as complementary methods. In the case of sintering, BiFeO3 phase was obtained from the mixture of precursors with 3 and 5 % excess of Bi2O3 during heating at 1023 K. Small amounts of...
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Unusual dynamics and nonlinear thermal self-focusing of initially focused magnetoacoustic beams in a plasma
PublicationUnusual thermal self-focusing of two-dimensional beams in plasma which axis is parallel to the equilibrium straight magnetic field is considered. The equi- librium parameters of plasma determine scenario of a beam divergence (usual or unusual) which is stronger as compared with a flow without magnetic field. Nonlinear thermal self-action of a magnetosonic beam behaves differently in the ordinary and unusual cases. Damping of wave...
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Damage detection in beams using wavelet transform on higher vibration modes
PublicationNiniejsza praca poświęcona jest technice diagnostyki konstrukcji bazującej na transformacie falkowej. Badany obiekt to belka wspornikowa z uszkodzeniami w formie nacięcia o głębokości 20%, 10% oraz 5% wysokości belki. Pomiary postaci drgań wykonano za pomocą nowoczesnego wibrometru laserowego. Celem pracy jest przedstawienie eksperymentalnych i numerycznych analiz wpływu wyższych postaci drgań na efektywność wykrywania uszkodzeń...
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Discussion - Experimental study of dapped–end beams subjected to inclined load
PublicationDiscussion - Experimental study of dapped–end beams subjected to inclined load
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Debonding Detection in Reinforced Concrete Beams with the Use of Guided Wave Propagation
PublicationOne of the most frequent damage of the reinforced concrete structures is debonding between steel bar and concrete cover. In the case of debonding occurrence not only the strength of the structure decreases, but also it is more vulnerable to corrosion damages. For this reason fast and effective methods of debonding detection in an early stage of its development need a significant boost. The paper presents analytical and experimental...
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Surface texture of pine wood beams after planing in industrial conditions
PublicationMeasuring the surface features of wooden components after planing is connected with the rising demands regarding to the quality of the painted window frames. In the paper the complex surface texture analysis especially identifying of surface damages using non-contact 3D measurement techniques for precise area measurement were presented.This enabled the study of irregular surface features with sufficient fidelity and resolution....
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Experimental Verification of Natural Vibration Models of Steel-concrete Composite Beams
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Thermal Self-Action of Acoustic Beams Containing Several Shock Fronts
PublicationThermal self-action of an acoustic beam with one discontinuity or several shock fronts is studied in a Newtonian fluid. The stationary self-action of a single sawtooth wave with discontinuity (or some integer number of these waves), symmetric or asymmetric, is considered in the cases of self-focusing and self- defocusing media. The results are compared with the non-stationary thermal self-action of the periodic sound. Thermal self-action...
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BEHAVIOR OF REINFORCED CONCRETE BEAMS CONTAINING LIGHTWEIGHT AGGREGATE IN THE TENSILE ZONE
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RMS-based damage detection in reinforced concrete beams: numerical simulations
PublicationImage-based damage detection methods using guided waves are well known and widely applied approaches in structural diagnostics. They are usually utilized in detection of surface damages or defects of plate-like structures. The article presents results of the study of applicability of imaging wave-based methods in detection in miniscule internal damage in the form of debonding. The investigations were carried out on numerical models...
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Structural Assessment of Reinforced Concrete Beams Incorporating Waste Plastic Straws
PublicationThe behavior of reinforced concrete beams containing fibers made of waste plastic straws (WPSs) under the three point bending test is examined. The effect of WPS fiber addition on the compressive and split tensile strength is reported. Four concrete mixes were prepared. The control mix PS-0 had a proportion of 1 cement: 1 sand: 2 coarse aggregate and a water cement ratio of 0.4. In the other three mixes PS-0.5, PS-1.5 and PS-3,...
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Cavitation erosion of steels processed by CO2 laser beams of various parameters.
PublicationPrzedstawiono wpływ parametrów przetapiania stali za pomocą wiązki lasera CO2 na jej własności kawitacyjne. Do badań użyto stali 45, 2H13 i OH18N9. Wyniki badań wskazują na znaczny wpływ parametrów przetapiania na poziom odporności kawitacyjnej stali.
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Investigation of influence of space mopdes interaction on nonlinear dynamics of sound beams
PublicationOperatory rzutu na mody są zdefiniowane w dynamice płynów trójwymiarowych. Zostały wyprowadzone równania ewolucyjne. Rezultaty obliczeń numerycznych przedstawione.
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On the exact equilibrium conditions of irregular shells reinforced by beams along the junctions
PublicationThe exact, resultant equilibrium conditions for irregular shells reinforced by beams along the junctions are formulated. The equilibrium conditions are derived by performing direct integration of the global equilibrium conditions of continuum mechanics. New, exact resultant static continuity conditions along the singular curve modelling reinforced junction are presented. The results do not depend on shell thickness, internal through-the-thickness...
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Identification of discontinuites in composite rods and beams based on Lamb wave propagation
PublicationW pracy omówiono metodę identyfikacji typu nieciągłości w belkach i prętach kompozytowych, oparta o analizę zmain w propagacji fali Lamba.
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Experimental investigations of size effect in reinforced concrete beams failing by shear
PublicationW artykule omówiono wyniki doświadczalne efektu skali w zbrojonych betonowych belkach niszczących się przez ścinanie. Doświadczenia wykonano dla belek o różnych wymiarach ze zbrojeniem stalowym i bazaltowym. Podczas doświadczeń pomierzono siłę oraz szerokości lokalizacji i rys. Wyniki porównano z modelem skali wg Bazanta.
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Multi-scale modelling of concrete beams subjected to three-point bending
PublicationW artykule przedstawiono wyniki numeryczne MES dwuskalowego modelowania belek betonowych z nacięciem na poziomie skali makro i mezo. Obliczenia wykonano przy wykorzystaniu modelu degradacji sztywności z nielokalnym osłabieniem. Beton został opisany na poziomie skali mezo jako stochastyczny materiał 3-składnikowy złożony z kruszywa, zaczynu cementowego oraz stref kontaktu. Natomiast na poziomie skali makro został opisany jako materiał...
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Investigations on strength and fracture in RC beams scaled along height or length
PublicationThe objective of the present paper is to identify experimentally and theoretically differing failure mechanisms in reinforced concrete beams subjected to four-point bending for a separate variation of the depth and length at the constant thickness. Experiments were performed on reinforced concrete beams under four-point bending. Different failure mechanisms included steel yielding, diagonal tension or shear- compression depending...
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The congruence of mental models in entrepreneurial teams – implications for performance and satisfaction in teams operating in an emerging economy
PublicationPurpose – The paper aims to explore the relationship between the congruence of mental models held by the members of entrepreneurial teams operating in an emerging economy (Poland) and entrepreneurial outcomes (performance and satisfaction). Design/methodology/approach – The data obtained from 18 nascent and 20 established entrepreneurial teams was analysed to answer hypotheses. The research was quantitative and was conducted using...
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Double wedge prism based beam deflector for precise laser beam steering
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Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams
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Trust triggers and barriers in intercultural teams
PublicationIntercultural teams are more and more popular nowadays — they constitute a serious challenge in terms of effective cooperation and trust building, however. The article presents the potential problems that can affect intercultural cooperation and stresses the power of trust in cultural diversity conditions. The ten-factor model of intercultural team trust is presented. The main aim was to answer the questions: what are the differences...
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COMPARATIVE STUDY OF TRADITIONAL AND VIRTUAL TEAMS
PublicationThe paper presents two kinds of cooperating teams: traditional and virtual, and proposes a new measure of the team virtuality level. Some representative teamwork characteristics, such as team member competencies, team diversity, leadership, and team decision-making are analyzed and compared depending on the degree of virtuality. Moreover, the team climate as one of the team performance measures is also analyzed and compared in...
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The preferable ways of decision-making in IT teams
PublicationSoftware development team collaboration requires various decisions regarding essential aspects of a project’s progress. General and particular decision-making models are considered, and their main aspects such as team types, problem solving categories, and decision-making ways are analyzed. The research concerns representative groups of IT specialists and their preferences in decision-making are investigated. Four possible cases were...
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Static analysis of grids assembled with thin-walled beams of the open cross-section
PublicationPraca dotyczny analizy statycznej rusztów zbudowanych z prętów cienkościennych. Przedstawiono w niej koncepcję metody modelowania konstrukcji dźwigarów cienkościennych i rusztów z wykorzystaniem superelementów w połączeniu z klasyczną teorią belek cienkościennych o przekroju nieodkształcalnym. Zamieszczono wyniki przeprowadzonej eksperymentalnej weryfikacji badań teoretycznych.
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The method of analysis of damage reinforced concrete beams using terrestial laser scanning
PublicationThe authors present an analysis of the possibility to assess deformations and mechanisms of destructing bent reinforced concrete beams using the terrestrial laser scanning. As part of the experiments carried out at the Regional Laboratory of Construction of the Concrete Structures Division of the Civil and Environmental Engineering Faculty at Gdansk University of Technology, the reinforced concrete beams were subjected to destruction...
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Experimental Tests Of Sandwich Beams In The Design Process Of GFRP Shell Footbridge Structure
PublicationThe paper includes selected aspects of the study to elaborate architectural, material and construction design of pedestrian footbridge spans made of composite materials. The considered footbridge is a sandwich-type shell structure. The cooperation of PET foam core with outer lining surfaces is crucial for its load bearing capacity. The paper is aimed to experimental investigation of sandwich beams subjected to bending loading....
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Time Projection Chamber (TPC) detectors for nuclear astrophysics studies with gamma beams
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THE METHOD OF ANALYSIS OF DAMAGE REINFORCED CONCRETE BEAMS USING TERRESTRIAL LASER SCANNING
PublicationThe authors present an analysis of the possibility to assess deformations and mode of failure of R-C beams using terrestrial laser scanning. As part of experiments carried out at the Regional Laboratory of Construction (at Gdansk University of Technology), reinforced concrete beams were subjected to destruction by bending and by shear. The process of press impact on the reinforced concrete beam was recorded using terrestrial laser...
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An isogeometric finite element formulation for geometrically exact Timoshenko beams with extensible directors
PublicationAn isogeometric finite element formulation for geometrically and materially nonlinear Timoshenko beams is presented, which incorporates in-plane deformation of the cross-section described by two extensible director vectors. Since those directors belong to the space R3, a configuration can be additively updated. The developed formulation allows direct application of nonlinear three-dimensional constitutive equations without zero...
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Performance of isotropic constitutive laws in simulating failure mechanisms in scaled RC beams
PublicationResults of numerical calculations of reinforced concrete (RC) beams are presented. Based on experimental results on longitudinally reinforced specimens of different sizes and shapes are investigated. Four different continuum constitutive laws with isotropic softening are used: one defined within continuum damage mechanics, an elasto-plastic with the Rankine criterion in tension and the Drucker-Prager criterion in compression, a...
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Nonlocalized thermal behavior of rotating micromachined beams under dynamic and thermodynamic loads
PublicationRotating micromachined beams are one of the most practical devices with several applications from power generation to aerospace industries. Moreover, recent advances in micromachining technology have led to huge interests in fabricating miniature turbines, gyroscopes and microsensors thanks to their high quality/reliability performances. To this end, this article is organized to examine the axial dynamic reaction of a rotating...
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Neutral Dissociation of Pyridine Evoked by Irradiation of Ionized Atomic and Molecular Hydrogen Beams
PublicationThe interactions of ions with molecules and the determination of their dissociation patterns are challenging endeavors of fundamental importance for theoretical and experimental science. In particular, the investigations on bond-breaking and new bond-forming processes triggered by the ionic impact may shed light on the stellar wind interaction with interstellar media, ionic beam irradiations of the living cells, ion-track nanotechnology,...
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A Diagnostic Method Based on Deflection Analysis for Monitoring Post-elastic Response of Beams
PublicationA non-destructive diagnostic method based on deflection analysis for monitoring the post-elastic response of beams was developed, and a diagnostic indicator was proposed. The indicator was defined as the second moment of the normalised curvature function about the mid-span, where the curvature was computed from the normalised deflection function. Elastic reference values of the indicator were computed for simply supported beams...
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Assessment of Wooden Beams from Historical Buildings Using Ultrasonic Transmission Tomography
PublicationThe main goal of this study was non-destructive evaluation of wooden elements using ultrasonic waves. The inspection was carried out on wooden beams from a historical object. Elastic wave signals were processed by ultrasonic transmission tomography to obtain imaging of the internal structure of tested elements without disturbing their state and integrity. The focus was on the influence of wood anisotropy on the propagation of ultrasonic...
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Characterization of corrosion in reinforced concrete beams using destructive and non-destructive tests
PublicationThe paper presents both non-destructive and destructive experimental tests on steel-reinforced concrete beams subjected to electrochemical corrosion. To examine the condition and behavior of the specimens, destructive tests were carried out, i.e., a three-point bending together with a modulated ultrasonic wave test. In addition, a series of non-destructive experiments were conducted, such as the potential measurement method, low-frequency...
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A novel section–section potential for short-range interactions between plane beams
PublicationWe derive a novel formulation for the interaction potential between deformable fibers due to short-range fields arising from intermolecular forces. The formulation improves the existing section–section interaction potential law for in-plane beams by considering an offset between interacting cross sections. The new law is asymptotically consistent, which is particularly beneficial for computationally demanding scenarios involving...
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Spectral criterion of infinite fatigue life of beams under asymmetric random loads
PublicationRozpatrywana jest trwałość zmęczeniowa belek poddanych stałym i zmiennym obciążeniom osiowym, giętnym i skrętnym o znanych gęstościach widmowych mocy. Założono, że materiał posiada granicę zmęczenia i jest zgodny z modelem Kelvina-Voigta, oraz że składowe naprężenia są stacjonarne, stacjonarnie skorelowane i różniczkowalne w sensie średniokwadratowym. Zdefiniowano naprężenie równoważne i sformułowano kryterium nieograniczonej trwałości...
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Spectral criterion of infinite fatigue life of beams under combined random loads
PublicationRozpatrywana jest trwałość zmęczeniowa belek poddanych zmiennym obciążeniom osiowym, giętnym i skrętnym o znanych gęstościach widmowych mocy i zerowych wartościach średnich. Założono, że materiał posiada granicę zmęczenia i jest zgodny z modelem Kelvina-Voigta, oraz że składowe naprężenia są stacjonarne, stacjonarnie skorelowane i różniczkowalne w sensie średniokwadratowym. Zdefiniowano naprężenie równoważne i sformułowano kryterium...