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Search results for: FAILURE CHARACTERISATION
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Numerical analysis of lumbar spine injury during road safety barrier collision
PublicationPurpose: Enhancing road safety is a critical goal worldwide, necessitating the development of clear standards for road safety systems. This study focuses on lumbar spine (L-spine) compression injuries during collisions with concrete road safety barriers (RSBs). It aims to analyze internal forces during impact to understand L-spine injury biomechanics in such accidents. Methods: The research included a literature review, analyzing...
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Microcracking monitoring and damage detection of graphene nanoplatelets-cement composites based on acoustic emission technology
PublicationThis study aims to identify the micro-cracking pattern and structural applications of cement composites replaced with 0 wt%, 0.04 wt%, and 0.08 wt% contents of graphene nanoplatelets (GNPs) over cement weight through acoustic emission (AE) monitoring under mechanical degradation. The ultraviolet-visible spectroscopy (UV–vis) results showed that at 60 min sonication period, GNP-4 showed maximum absorbance rate of 16.15% compared...
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Some problems of slide bearing material fatigue evaluation.
PublicationA slide bearing alloy resistance against fatigue failures have been investigated for three different lubricants, different heat loadings and different stress ratio κ values. The research methods and data handling procedures for determination of particular parameter effects on fatigue strength have been described and analysed for experiments that were set and performed in laboratory tester SKMR-2. Main and interaction effects of...
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Employing economical methods for pavement defects estimation
PublicationIt is a common practise that measurements of road surface conditions are made using professional and expensive apparatus. Typically a van or a truck equipped with a set of professional sensors i.e. laser scanners of surface is used, therefore the measurement update period is often quite long. Two alternative low-cost methods for estimating road pavement defects and failures were proposed and investigated by the authors. The first...
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Application of analytical methods for the determination of bioactive compounds in some berries
PublicationFluorometry, ESI-MS, FTIR, and radical scavenging assays were used for characterization of bioactive compounds and the levels of their antioxidant activities. Polyphenols, flavonoids, anthocyanins, and ascorbic acid and the level of antioxidant activity of water extracts of “Murtilla-like” [Myrteola nummularia (Poiret) Berg.], and other widely consumed berries were determined and compared. The contents of bioactive compounds and...
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Type III Responses to Transient Inputs in Hybrid Nonlinear Neuron Models
PublicationExperimental characterization of neuronal dynamics involves recording both of spontaneous activity patterns and of responses to transient and sustained inputs. While much theoretical attention has been devoted to the spontaneous activity of neurons, less is known about the dynamic mechanisms shaping their responses to transient inputs, although these bear significant physiological relevance. Here, we study responses to transient...
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Probabilistic sensitivity of limit states of structures : The Monte Carlo simulation
PublicationThe main issue of the paper is the probabilistic sensitivity of the limit states of structures with respect to selected input design variables. Attempt to the problem is done by the dedicated Monte Carlo simulation procedure. Basic design variables are random variables of given probability distributions, presented in the form of random numbers. Uni-parametrical increment of the dominant basic variable (basic variables) is done,...
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Monitoring of CRT by means of impedance multiple measurements - simulation studies
PublicationCardiac resynchronization therapy (CRT) is a very promising treatment for patients with congestive heart failure. An Impedance Cardiography (ICG) is used for evaluation of heart mechanical activity. A simulation study with the use of a FEM model was performed. The developed realistic model of the thorax, based on CT data obtained from examination of a 68-year-old man, consisted of 212 000 tetrahedral elements. Different configurations...
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Viscoplastic damage analysis of structures subjected to impact loading. Plate and shell structures. - Ł. Pyrzowski.
PublicationThe work presents the investigation in the response of plate-shell structures subjected to impact loading (gas mixture explosions). This phenomenon is studied in the context of its mechanical aspects, mainly the ductile fracture prediction. The work starts with the literature review and the description of theories, which are nowadays the most popular in the damage and failure modelling. After selecting the theoretical models and...
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The impact of material degradation on the resistance and reliability of truss structures
PublicationThe paper analyses limit load-carrying capacity and buckling load of truss towers used to support high voltage power lines. The analysed typical structure was subjected to characteristic loads and their combinations. The results were applied to assess structural resistance with regard to steel corrosion in the long-term operation. The extent of structural deterioration was assessed due to Young's modulus decrement in the course...
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A Survey Investigating the Influence of Business Analysis Techniques on Software Quality Characteristics
PublicationBusiness analysis is recognized as one of the most important areas determining the outcome (success or failure) of a software project. In this paper we explore this subject further by investigating the potential impact of techniques applied in business analysis on essential software quality characteristics. We conducted a literature search for software quality models, analyzed the existing models and selected a subset of commonly...
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Response of a steel tank during earthquakes and mining tremors - experimental investigation
PublicationCylindrical steel tanks are very popular shell structures used to store the products of chemical and petroleum industries. Any failure might have disastrous consequences, therefore their safety and reliability is essential. Earthquakes are the most dangerous and also the most unpredictable dynamic loads acting on such structures. On the other hand, mining tremors are usually considered to be less severe due to lower acceleration...
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APPLICATION OF INFRARED THERMOGRAPHY TO NON-CONTACT TESTING OF AD/DC POWER SUPPLY
PublicationTesting of AC/DC power supplies using the thermography was carried out in order to assess their assembly and operation correctness before launching them on the market. The investigation was carried out for 17 AC/DC power supplies which passed the standard tests (measurements of their basic parameters and characteristics). The investigation consisted of two steps. In the first step the dispersion of temperature on power supply boards...
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Traffic-induced vibrations. The impact on buildings and people
PublicationTraffic-induced vibrations have recently been of major concern to engineers as one of the aspects of so called physical environmental pollution. The interest is related to the observations of serious negative effects of such kind of vibrations on buildings and their inhabitants. Traffic-induced vibrations may cause plaster cracks, structural damage and even failure and collapse of the structure. They may also be the reason of serious...
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Local and global response of sandwich beams made of GFRP facings and PET foam core in three point bending test
PublicationIn the paper behaviour of laminated sandwich beams (FRP face sheet – PET foam core – FRP face sheet) subjected to three point bending is studied. The paper aim is to find practical descriptions enabling effective and accurate estimation of the elastic response, damage and failure of the beams, basing on experiments and static calculations. Therefore a number of tests are described, that were done on laminated coupons and foam specimens...
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Polynomial Algorithm for Minimal (1,2)-Dominating Set in Networks
PublicationDominating sets find application in a variety of networks. A subset of nodes D is a (1,2)-dominating set in a graph G=(V,E) if every node not in D is adjacent to a node in D and is also at most a distance of 2 to another node from D. In networks, (1,2)-dominating sets have a higher fault tolerance and provide a higher reliability of services in case of failure. However, finding such the smallest set is NP-hard. In this paper, we...
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Experimental Investigation of the Performance of an Innovative Implantable Left Ventricular Assist Device—Proof of Concept
PublicationThis paper presents the results of experimental performance of an innovative left ventricular assist device working on a specially designed test stand. The introduced invention is mainly applied for supporting the heart in patients with end-stage heart failure accompanied by mitral valve regurgitation and pulmonary hypertension. Moreover, the developed device has the form of a flexible balloon forming an intracardiac inert gas-filled...
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Asynchronous WAM with Irregular Pulse Repetition
PublicationRadiolocation systems for aviation based on Multi-Lateration (MLAT) typically use a set of synchronised ground sensors to receive radio signals broadcast by onboard transmitters. In most cases, the sensor synchronisation in Wide Area Multi-Lateration Systems (WAM) is provided by Global Navigation Satellite System (GNSS) receivers. However, in the case of synchronisation failure, there is still a possibility to estimate the coordinates...
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Numerical Model of the Aortic Valve Implanted Within Real Human Aorta
PublicationCardiovascular system diseases are the main cause of deaths in developed and developing countries. The main reasons are myocardial infarction, heart failure, stroke and valvular diseases. These are caused mainly by arteriosclerosis. The valvular diseases involve a significant burden for the health care system and their frequency is rising with the patient age. This work describes the tools and numerical models appropriate for modeling...
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Upoważnienie do zaciągania zobowiązań na rzecz jednostek samorządu terytorialnego jako naruszenie dyscypliny finansów publicznych
PublicationArtykuł poświęcony jest zagadnieniu upoważnienia do zaciągania zobowiązań na rzecz jednostek samorządu terytorialnego. W teoretycznej części zdefiniowano dwa pojęcia: zobowiązań oraz zaciągania zobowiązań. Następnie scharakteryzowano zagadnienie podmiotowego i przedmiotowego zaciągania zobowiązań. Nieprzestrzeganie przepisów dotyczących zaciągania zobowiązań, które zawarte są głównie w ustawie o finansach publicznych, prowadzi...
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Fluorescence of p-hydroxyazobenzocrowns – Tautomeric equilibrium effect
PublicationThe spectroscopic properties of a series of para-hydroxyazobenzocrowns, including three novel compounds, were investigated using UV–Vis absorption and emission spectroscopy. This study presents, for the first time, determined quantum yield (QY) values for macrocycles of this category, ranging between 0.122 and 0.195. The highest values were obtained for crowns bearing two phenyl substituents in benzene rings. The impact of aromatic...
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Superconductivity of Ta-Hf and Ta-Zr alloys: Potential alloys for use in superconducting devices
PublicationThe electronic properties relevant to superconductivity are reported for bulk Ta-Hf and Ta-Zr body centered cubic alloys, in a large part to determine whether their properties are suitable for potential use in superconducting qbits. The body centered cubic unit cell sizes increase with increasing alloying. The results of magnetic susceptibility, electrical resistivity, and heat capacity characterization are reported. While elemental...
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Anti-plane surface waves in media with surface structure: Discrete vs. continuum model
PublicationWe present a comparison of the dispersion relations derived for anti-plane surface waves using the two distinct approaches of the surface elasticity vis-a-vis the lattice dynamics. We consider an elastic half-space with surface stresses described within the Gurtin–Murdoch model, and present a formulation of its discrete counterpart that is a square lattice half-plane with surface row of particles having mass and elastic bonds different...
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Motor bearing diagnostics performed by means of laser vibrometer
PublicationDamage of bearings is the most common cause of failures in squirrel-cage induction motors. That is why the issues connected with diagnostics of bearings are so important. The equipment employed for bearing diagnostics usually makes use of vibrations as the criterion for technical condition of the bearings. This paper presents exemplary results of the research conducted on bearings with artificially introduced damage. A scanning...
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Combined method of multibeam sonar signal processing and image analysis for seafloor classification
PublicationThe combined approach to seafloor characterisation was investigated. It relies on calculation of several descriptors (parameters) related to seabed type using three types of multibeam sonar data obtained during seafloor sensing: 1) the grey-level sonar images (echograms) of seabed, 2) the 3D model of the seabed surface which consists of bathymetric data, 3) the set of time domain bottom echo envelopes received in the consecutive...
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The Occurrence and Role of Tetrasphaera in Enhanced Biological Phosphorus Removal Systems
PublicationThe application of enhanced biological phosphorus removal (EBPR) in wastewater treatment plants (WWTPs) has commonly been utilized worldwide. However, the optimum efficiency has not been realized over the past decades, prompting many studies and publications. The limitations, especially comprehension of the abundance and actual potential of polyphosphate-accumulating organisms (PAOs), are not fully understood. Recently identified...
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“Shadow” vs. “Phase 3D” method within endoscopic examinations of marine engines
PublicationA visual investigation of surfaces creating internal, working spaces of marine combustion engines by means of specialized view-finders so called endoscopes is at present almost a basic method of technical diag-nostics. The surface structure of constructional material is visible during investigations like through the magnifying glass (usually with a precisely determined magnification), which makes possible a detection, recognition...
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Projektowanie, synteza i charakterystyka fotokatalizatorów nowej generacji na bazie związku Ti3C2Tx do usuwania aktywnych substancji farmaceutycznych
PublicationCelem niniejszej pracy było zastosowanie materiałów nowej generacji na bazie związku Ti3C2Tx w procesach fotokatalitycznej degradacji aktywnych substancji farmaceutycznych: karbamazepiny, acetaminofenu i ibuprofenu. Zakres prac badawczych obejmował syntezę fotokatalizatorów, charakterystykę ich właściwości fizykochemicznych, oraz ocenę aktywności fotokatalitycznej. Przedstawiono możliwość zastosowania węglika tytanu jako kokatalizatora...
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Application of thin diamond films in low-coherence fiber-optic Fabry Pérot displacement sensor
PublicationThe novel fiber-optic low coherence sensor with thin diamond films is demonstrated. The undoped and boron-doped diamond films were elaborated by the use of the microwave plasma enhanced chemical vapor deposition (μPE CVD) system. The optical signal from the Fabry–Pérot cavity made with the application of those thin films is sensitive to displacement. The sensor characterization was made in the range of 0–600 μm. The measurements...
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Synthetic Principles Determining Local Organization of Copolyesters Prepared from Lactones and Macrolactones
PublicationA highly effective and facile technique for catalytic ring-opening copolymerization (cROP) of lactones viz. ε- caprolactone and ε-decalactone with ω-pentadecalactone is being described. The reactions were mediated by Zn- and Cabased tridentate Schiff base complexes and benzyl alcohol as initiator. The catalysts were successfully employed for the preparation of numerous block and random copolymers. To unravel the composition of...
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Nanoparticle-free tissue-mimicking phantoms with intrinsic scattering
PublicationWe present an alternative to the conventional approach, phantoms without scattering nanoparticles, where scattering is achieved by the material itself: spherical cavities trapped in a silicone matrix. We describe the properties and fabrication of novel optical phantoms based on a silicone elastomer polydimethylsiloxane (PDMS) and glycerol mixture. Optical properties (absorption coefficient µa, reduced scattering coefficient µs',...
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Rearrangement of azoxybenzocrowns into chromophoric hydroxyazobenzocrowns and the use of hydroxyazobenzocrowns for the synthesis of ionophoric biscrown compounds
PublicationThe Wallach rearrangement was used as a method for preparing p-hydroxyazobenzocrown ethers starting from different azoxybenzocrowns as substrates. Synthesis of a series of p-hydroxyazobenzocrowns under modified conditions and characterization of the obtained products are presented. o-Hydroxyazobenzocrowns were identified among the products of the photochemical rearrangement of azoxybenzocrowns. Novel biscrowns were synthesized...
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Capillary Electrophoresis in Determination of Low Molecular Mass Organic Acids
PublicationThis paper presents overviews the capabilities of capillary electrophoretic techniques to determine low molecular mass organic acids in a variety of aqueous, gas and solid samples. It mainly focuses on short - chain carboxylic acids containing one or more carboxylic groups and possibly some other functional groups (hydroxyl, keto-, amino- etc.). Finally the procedures applied to the determine the acids in different matrices are...
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Thermoplastic Elastomers Filled With GTR
PublicationIn recent years, searching for new and cost-effective methods of recycling waste tires has been a subject of research in many laboratories worldwide. This is due to regulations in the law and environmental factors, which have both stimulated industry to re-use high quality rubber found in ground tire rubber (GTR). One of the most promising solutions in this area seems to be thermoplastic elastomers (TPEs) filled with GTR, which...
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Superconductivity on a Bi Square Net in LiBi
PublicationWe present the crystallographic analysis, superconducting characterization and theoretical modeling of LiBi, that contains the lightest and the heaviest nonradioactive metal. The compound crystallizes in a tetragonal (CuAu-type) crystal structure with Bi square nets separated by Li planes (parameters a = 3.3636(1)Å and c = 4.2459(2) Å, c/a = 1.26). Superconducting state was studied in detail by magnetic susceptibility and heat...
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ALTERNATIVE, DIRECT SYNTHESIS METHOD OF THE CERAMIC SOLID SOLUTIONS BASED ON BaTiO3 THROUGH A HIGH ENERGY BALL MILLING
PublicationPolycrystalline samples BaTiO3 and the solid solutions Ba0.9Sr0.1TiO3, Ba0.9Sr0.1Ti0.9Sn0.1O3, Ba0.9Sr0.1Ti0.8Sn0.2O3 were obtained by means of a mechanochemical treatment based on the high-energy ball milling technique and next a high temperature solid state reaction method. The influence of synthesis condition on microstructural, dielectric and ferroelectric properties of obtained solid solutions were investigated. The structure...
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Nitrogen-Doped Diamond Film for Optical Investigation of Hemoglobin Concentration
PublicationIn this work we present the fabrication and characterization of a diamond film which can be utilized in the construction of optical sensors for the investigation of biological samples. We produced a nitrogen-doped diamond (NDD) film using a microwave plasma enhanced chemical vapor deposition (MWPECVD) system. The NDD film was investigated with the use of scanning electron microscopy (SEM), atomic force microscopy (AFM) and Raman...
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Restoration and preservation of the reinforced concrete poles of fence at the former Auschwitz concentration and extermination camp
PublicationThe objective of this study was to assess the present state of the reinforced concrete poles of fence at the former Auschwitz I and Auschwitz II-Birkenau concentration and extermination camp. The poles were subjected to renovation about 10 years ago. After this time some deficiencies of applied renovation method were noticed. Cracks appeared between fresh and original part of concrete cover. Analysis of the reasons of these failures...
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Restoration and preservation of the reinforced concrete poles of fence at the former Auschwitz concentration and extermination camp
PublicationThe objective of this study was to assess the present state of the reinforced concrete poles of fence at the former Auschwitz I and Auschwitz II-Birkenau concentration and extermination camp. The poles were subjected to renovation about 10 years ago. After this time some deficiencies of applied renovation method were noticed. Cracks appeared between fresh and original part of concrete cover. Analysis of the reasons of these failures...
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Rural Landscape Planning for Sustainable Development. The Case of Poland
PublicationThis text results from theoretical study on the possibilities of rural landscape renovation in Poland. The introduction marks new spatial phenomena and the scope of their influence. It indicates social and cultural reasons of the changes, and states the need of their renewed interpretation. The second part of the article contains a description of the degrading cultural landscape of the country and presents its features. It then...
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Experimental study on steel columns subjected to impact load under earthquake conditions
PublicationEarthquakes affecting urbanized regions cause exceptional loads to load bearing structural elements such as columns. Such a boost in the load conditions can lead to severe damages which, in a worst case scenario, can lead to a total collapse of a building. This boost is caused by the horizontal ground movement generating a rise in the internal forces due to considerable large displacement between the top and bottom support of columns....
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Influence of operating pressure on the durability of a satellite hydraulic motor supplied by rapeseed oil
PublicationThis article describes the results of a durability test of a hydraulic satellite motor supplied by rapeseed oil. The tests were carried out on a test stand in a power recuperation system. The tests of the motor were carried out at a constant shaft speed for three fixed pressure drops in the motor. This made it possible to demonstrate the influence of the motor operating pressure on the durability of the satellite mechanism. The...
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The Smith-Watson-Topper parameter and fracture surface topography relationship for additively manufactured 18Ni300 steel subjected to uniaxial variable-amplitude loading
PublicationIn this paper, the association between Smith-Watson-Topper (SWT) parameter and fracture surface topography is studied in additively manufactured maraging steel exposed to variable-amplitude fatigue loading. The post-failure fracture surfaces were examined using a non-contact 3D surface topography measuring system and the entire fracture surface method. The focal point is on the correspondence between fatigue characteristics, articulate...
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Effect of austempering temperature on microstructure and cyclic deformation behaviour of multiphase low-carbon steel
PublicationThis paper examined the cyclic deformation behaviour of multiphase low-carbon steel that was subjected to austempering heat treatments at four temperatures (190 °C, 230 °C, 275 °C, and 315 °C) below the martensite start temperature (Ms = 353 °C). The tests were conducted at room temperature, under fully reversed strain-controlled conditions, with strain amplitudes in the range 0.5–1.0%. The microstructure was observed by transmission...
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Numerical simulations of overflow experiments on a model dike
PublicationDike failure due to overtopping is one of the important factors, which should be considered in the dike designing process. Although the overflow is characterized by the relatively low risk of occurrence, in many cases dikes are totally destroyed or seriously damaged. An interesting phenomenon occurring during overflow is the trapping of air in pores of the unsaturated soil material. As the infiltration progresses from all sides,...
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Monitoring Steel Bolted Joints during a Monotonic Tensile Test Using Linear and Nonlinear Lamb Wave Methods: A Feasibility Study
PublicationThe structural integrity of steel bolted joints may be compromised due to excessive loading. Therefore, condition assessment and the detection of potential defects before they cause a failure have become a major issue. The paper is focused on the condition monitoring of a bolted lap joint subjected to progressive degradation in a tensile test. The inspection used Lamb waves propagated through the overlap area. Wave propagation...
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Protection in elastic optical networks
PublicationIn this article, we analyze gains resulting from the use of EON architectures with special focus on transportation of cloud-ready and content-oriented traffic in the context of network resilience. EONs are a promising approach for future optical transport networks and, apart from improving the network spectral efficiency, bring such new capabilities as squeezed protection, which reduces resource requirements in failure scenarios....
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Design of dimensionally stable composites using efficient global optimization method
PublicationDimensionally stable material design is an important issue for space structures such as space laser communication systems, telescopes, and satellites. Suitably designed composite materials for this purpose can meet the functional and structural requirements. In this paper, it is aimed to design the dimensionally stable laminated composites by using efficient global optimization method. For this purpose, the composite plate optimization...
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On instabilities and post-buckling of piezomagnetic and flexomagnetic nanostructures
PublicationWe focus on the mechanical strength of piezomagnetic beam-like nanosize sensors during post-buckling. An effective flexomagnetic property is also taken into account. The modelled sensor is selected to be a Euler-Bernoulli type beam. Long-range interactions between atoms result in a mathematical model based on the nonlocal strain gradient elasticity approach (NSGT). Due to possible large deformations within a post-buckling phenomenon,...
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Flexural behavior of composite structural insulated panels with magnesium oxide board facings
PublicationThe current report is devoted to the flexural analysis of a composite structural insulated panel (CSIP) with magnesium oxide board facings and expanded polystyrene (EPS) core, that was recently introduced to the building industry. An advanced nonlinear FE model was created in the ABAQUS environment, able to simulate the CSIP’s flexural behavior in great detail. An original custom code procedure was developed, which allowed to include...