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Mechanical simulation of artificial gravity in torus-shaped and cylindrical spacecraft
PublikacjaLarge deformations and stress analyses in two types of space structures that are intended for people to live in space have been studied in this research. The structure under analysis is assumed to rotate around the central axis to create artificial gravitational acceleration equal to the gravity on the Earth's surface. The analysis is fully dynamic, which is formulated based on the energy method by using the first-order shear deformation...
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Model of Nutrient and Pesticide Outflow with Surface Water to Puck Bay (Southern Baltic Sea)
PublikacjaCoastal basins are particularly exposed to the adverse impact of anthropogenic stress. In many places, despite only the seasonal increase in the number of residents, progressive urbanization and associated changes in the catchment characteristics are noticeable. Puck Bay is part of the Gulf of Gdansk and belongs to the Baltic Sea. Although the area of Puck Bay is covered by the Natura 2000 Network, this has not saved it from eutrophication...
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Autistic Employees’ Technology-Based Workplace Accommodation Preferences Survey—Preliminary Findings
PublikacjaBackground: There has been an increase in the number of research studies focused on the design of accommodations aimed at improving the well-being and work performance of autistic employees. These accommodations took various forms; some of them were based on modification of management practices, for example, support in the area of effective communication, or involved modifications to the physical working environment aimed at limiting...
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Experimental investigations on the mechanical properties and damage detection of carbon nanotubes modified crumb rubber concrete
PublikacjaThis study presents a modified crumb rubber (MCR) concrete design mix reinforced with multi-walled carbon nanotubes (MWCNTs), mechanical characterization, and cracking monitoring using the acoustic emission (AE) technique. The results showed that the bridging effect of MWCNTs and MCR in the concrete mix mitigated the shortcomings of MWCNT-MCR concrete and improved the flexural and compressive strengths by 18.3% and 26.5%, respectively,...
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Tensile validation tests with failure criteria comparison for various GFRP laminates
PublikacjaThe paper studies the mechanical properties of glass fibre reinforced polymers (GFRP) with various types and orientation of reinforcement. Analyzed specimens manufactured in the infusion process are made of polymer vinyl ester resin reinforced with glass fibres. Several samples were examined containing different plies and various fibres orientation [0, 90] or [+45, –45]. To assess the mechanical parameters of laminates, a series...
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Nitric Oxide-Dependent Pathways as Critical Factors in the Consequences and Recovery after Brain Ischemic Hypoxia
PublikacjaBrain ischemia is one of the leading causes of disability and mortality worldwide. Nitric oxide (NO), a molecule that is involved in the regulation of proper blood flow, vasodilation, neuronal and glial activity constitutes the crucial factor that contributes to the development of pathological changes after stroke. One of the early consequences of a sudden interruption in the cerebral blood flow is the massive production of reactive...
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Effect of Tool Positioning Factors on the Strength of Dissimilar Friction Stir Welded Joints of AA7075-T6 and AA6061-T6
PublikacjaFriction Stir Welding (FSW) is a solid-state bonding technique. There are many direct and indirect factors affecting the mechanical and microstructural properties of the FSW joints. Tool offset, tilt angle, and plunge depth are determinative tool positioning in the FSW process. Investigating the effect of these factors simultaneously with other parameters such as process speeds (rotational speed and translational speed) and tool...
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Effect of bending-torsion on fracture and fatigue life for 18Ni300 steel specimens produced by SLM
PublikacjaIn this study, different fracture surfaces caused by fatigue failure were generated from 18Ni300 steel produced by selective laser melting (SLM). Hollow round bars with a transverse hole were tested under bending-torsion to investigate the crack initiation mechanisms and fatigue life. Next, the post-failure fracture surfaces were examined by optical profilometer and scanning electron microscope. The focus is placed on the relationship...
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ANTIOXIDANT POWER SERIES (APS) AS A TOOL FOR RATIONAL DESIGN AND ASSESSMENT OF HEALTH PROMOTING PROPERTIES OF FUNCTONAL FOODS BASED ON ANTIOXIDANT PHYTOCHEMICALS
PublikacjaOver past decades, plantborne antioxidants dominated so called "translational research" in the area of food, nutrition, and disease prevention. Among consumers and producers, such phytochemicals are synonyms of nutriceuticals. Popularity and commercial success of antioxidants stems from mechanistic studies suggesting the involvement of reactive oxygen species in etiology of chronic diseases. However, epidemiology failed to provide...
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The thermal effort during marine steam turbine flooding with water
PublikacjaThe work discussed an extreme case of cooling a steam turbine. The ship's steam turbine was used as an example. In marine transport units with low-speed engines dominate, however, there are also units with steam turbines. An example of analysed marine steam turbine is shown in Fig. 1. When considering the issue of cooling steam turbines, it is necessary to estimate the extreme conditions that may occur during operation of the turbine....
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Comparison of strain results at a laser weld notch obtained by numerical calculations and experimental measurements
PublikacjaIn the development of ship structures applying new materials and it’s purposeful placement play an important role. During the last years, especially in a construction of ro-ro type vessels, the usage of novel sandwich structures in cargo decks is profitable. Steel sandwich panel is an innovative solution which at a todays state of development can be used for the construction of any members not taking part in a global bending of...
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Processing of point cloud data retrieved from terrestrial laser scanning for structural modeling by Finite Element Method
PublikacjaFinite Element Method is one most popular contemporary method of strength analysis. The method is an advanced method for solving differential equations, based on discretization, which means that area is divided into finite elements. Each finite element has a solution of the equation approximated by specific functions and performing the actual calculations only for nodes of this division. Finite Element Method is widely used in...
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On a Recurrence Arising in Graph Compression
PublikacjaIn a recently proposed graphical compression algorithm by Choi and Szpankowski (2012), the following tree arose in the course of the analysis. The root contains n balls that are consequently distributed between two subtrees according to a simple rule: In each step, all balls independently move down to the left subtree (say with probability p) or the right subtree (with probability 1p). A new node is created as long as...
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Toolgraph Design of Optimal and Feasible Control Strategies for Time-Varying Dynamical Systems
PublikacjaArtykuł prezentuje nową metodę projektowania optymalnych i realizowanych strategii sterowania dla wariantnych procesów dynamicznych. Centralnym ośrodkiem i narzędziem tej metody jest struktura grafu przepływowego reprezentująca istotne właściwości autonomicznej dynamiki danego procesu w przestrzeni czasowo-stanowej, składającej się z elementarnych segmentów. Strukturę tę nazywamy grafem narzędziowym przestrzeni czasowo-stanowej....
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In Silico Safety Assessment of Bacillus Isolated from Polish Bee Pollen and Bee Bread as Novel Probiotic Candidates
PublikacjaBacillus species isolated from Polish bee pollen (BP) and bee bread (BB) were characterized for in silico probiotic and safety attributes. A probiogenomics approach was used, and in-depth genomic analysis was performed using a wide array of bioinformatics tools to investigate the presence of virulence and antibiotic resistance properties, mobile genetic elements, and secondary metabolites. Functional annotation and Carbohydrate-Active...
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X-Ray Computer Tomography Study of Degradation of the Zircaloy-2 Tubes Oxidized at High Temperatures
PublikacjaThe investigations of high-temperature oxidation of zirconium alloys, applied for fuel pellets in nuclear power plants, are usually limited to oxidation kinetics, phase transformations and microstructural characterization. The purpose of this research was to characterize the degradation phenomena occurring within oxide layer and at the interface oxide/metal, on internal and external Zircaloy-2 tube...
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The FEM analysis of pressure installation elements after simulated accidental overheating
PublikacjaThe paper presents innovative analysis focused on the safety aspects of existing pressure installation operation after overheating accidents. Results presented here can be applied in decision-making process concerning further operation of existing pressure installation after cooling system failure. In this paper the results of FEM analysis performed for a straight pipe and 90 degrees elbow, made of super duplex stainless steel,...
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Study of microstress state of P91 steel using complementary mechanical Barkhausen, magnetoacoustic emission, and X-ray diffraction techniques
PublikacjaThe paper deals with assessment of microstress state of martensite P91 steel using three complementary techniques: mechanical Barkhausen emission, magnetoacoustic emission (MAE), and X-ray diffraction (XRD) profile analysis. Magnetic coercivity Hc and microstructure were investigated with inductive magnetometry and magnetic force microscopy (MFM), respectively. Internal stress level of P91 steel was modified by heat treatment....
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A Flexible Nafion Coated Enzyme‐free Glucose Sensor Based on Au‐dimpled Ti Structures
PublikacjaThe detection of glucose at low concentrations using electrochemical sensors is of great importance due to the possibility of using different human body fluids than blood, such as e.g. urine, saliva, sweat or tears. The interest behind those biofluids is related to their utility in non-invasive sugar determination. In this work, we present flexible, fully biocompatible electrode material based on Au nanoparticles immobilized onto...
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THREE-LEVEL F-TYPE INVERTER
PublikacjaGiven the recent available IGBT switch modules up to 6.5 kV, 1200 A rating, the prospect of the diode-free variant topology of the three-level neutral-point-clamped (3-level, T-type) inverter in certain medium voltage applications is bright; due to its small part count and low conduction losses compared to the diode-clamped NPC inverter. However, within this voltage range, the input dc voltage rating of 50% of the switches per...
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Load path sensitivity and multiaxial fatigue life prediction of metals under non-proportional loadings
PublikacjaEngineering components often operate under complex loadings, in which the variable amplitude multiaxial stresses are raised by geometric discontinuities including holes, grooves, fillets and shoulders, etc. Besides, the non-proportional loading will lead to the rotation of maximum principal stress/strain and additional fatigue damage of structural elements in service. Consequently, the multiaxial and non-proportional loading have...
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Interactions of telomeric proteins with nucleic acids: sequence recognition on intact and oxidatively damaged telomeres
PublikacjaTelomeres are complex nucleoprotein assemblies that play a vital role in the maintenance of functional ends of linear chromosomes. Telomeric DNA, composed of tandem repeats of the 5'-TTAGGG-3' motif, solves the so-called end replication problem: as chromosomes shorten with each cell division, no information is lost, and the telomere can be re-extended. In the cell, many protein factors regulate telomere length, nuclear positioning...
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Nonlinear free and forced vibrations of a dielectric elastomer-based microcantilever for atomic force microscopy
PublikacjaThe majority of atomic force microcode (AFM) probes work based on piezoelectric actuation. However, some undesirable phenomena such as creep and hysteresis may appear in the piezoelectric actuators that limit their applications. This paper proposes a novel AFM probe based on dielectric elastomer actuators (DEAs). The DE is modeled via the use of a hyperelastic Cosserat model. Size effects and geometric nonlinearity are included...
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Regulated Assembly of LPS, Its Structural Alterations and Cellular Response to LPS Defects
PublikacjaDistinguishing feature of the outer membrane (OM) of Gram-negative bacteria is its asymmetry due to the presence of lipopolysaccharide (LPS) in the outer leaflet of the OM and phospholipids in the inner leaflet. Recent studies have revealed the existence of regulatory controls that ensure a balanced biosynthesis of LPS and phospholipids, both of which are essential for bacterial viability. LPS provides the essential permeability...
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Interdisciplinary e-collaboration tools / Narzędzia interdyscyplinarnej e-współpracy
PublikacjaW projektach interdyscyplinarnych niezwykle ważnym czynnikiem jest aktywne konsultowanie i bezpośrednie zastosowanie relatywnie nowo powstałej dziedziny zwanej współpracą interdyscyplinarną. Nawiązywanie interdyscyplinarnej współpracy przynosi wiele korzyści, jednakże niejednokrotnie wiąże się z licznymi problemami i niedogodnościami, a także koniecznością ciągłego doszkalania się i rozszerzania kompetencji zawodowych. Na podstawie...
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Vision guided robot gripping systems
PublikacjaW rozdziale omawia się robotycki system wykorzystujący kamery streo. System taki zastępuje pracę człowieka przy przenoszeniu obiektów wielkowymiarowych (teoretycznie nieograniczonych) w przestrzeni trójwymiarowej. W rozważaniach uwzględniono pinholową kamerę (bezsoczewkową z bardzo małą aperturą/otworem) oraz prosty model zniekształcenia soczewkowego. Podano wartości poszczególnych parametrów. Zastosowano dwie konwencje notacyjne...
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The experience of movement in orbital space architecture: A narrative of weightlessness
PublikacjaBased upon a combination of architectural theories, the knowledge of space environment, and psychology of isolated and confined environments, this qualitative research aims to study orbital space settlement in a way to get the built space congenial to the human experience of movement. In this sense, sensors, self-propulsion or mechanical actuators, the inhabitant’s mental and visual capacity for movement, as well as the represented...
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Memetic approach for multi-objective overtime planning in software engineering projects
PublikacjaSoftware projects often suffer from unplanned overtime due to uncertainty and risk incurred due to changing requirement and attempt to meet up with time-to-market of the software product. This causes stress to developers and can result in poor quality. This paper presents a memetic algorithmic approach for solving the overtime-planning problem in software development projects. The problem is formulated as a three-objective optimization...
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Ultra-rare ultra-care: The unique burden of ultra rare disease caregiving
PublikacjaBackground: We sought to assesses the impact of caring for children with ultra rare diseases (URDs) on familycarers and to analyse the way these experiences differ among the caregivers of children diagnosed throughprenatal or newborn screening, and those with symptom-based diagnosis.Methods: A total of 200 caregivers of 219 URDs children completed an on-line survey regarding the challengesand experiences...
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Możliwości wykorzystania roślin kapustowatych na potrzeby rolnictwa zrównoważonego na przykładzie kapusty białej
PublikacjaRośliny kapustowate (Brassicaceae) stanowią najważniejszą grupę roślin o potencjalnym zastosowaniu na dużą skalę w ochronie środowiska. Wynika to głównie z dwóch własności ich fitokompleksu: zdolności wiązania zanieczyszczeń środowiskowych oraz wytwarzania substancji o aktywności skierowanej przeciwko agrofagom. Te cechy spowodowały, że proponuje się rolnicze wykorzystanie roślin kapustowatych w rewitalizacji terenów zdegradowanych...
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Numerical Model of Femur Part
PublikacjaThe aim of the study is to create a new more accurate method of femur part modelling by using the finite element method. According to this new method, a femur part is treated as a complex structure composed of trabecular bone (internal part) and cortical bone (external part). The internal part is modelled as a scaffold, thus the external part is modelled as a coat (i.e. covering). Applying the programme ABAQUS, there were created...
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Reinforced concrete thin wall dome after eighty years of operation in maritime climate environment
PublikacjaThe paper presents a description of the construction elements of the Gdynia Seaport main hall dome. Firstly, it provides information about the technical condition of the dome’s structure. Secondly, it examines the strength analysis of the thin-walled reinforced concrete dome covering. Throughout the last 80 years the building has been exposed to an unfavourable marine climate. The analysis of the state of stress and deformations...
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Polygons vs. clumps of discs: A numerical study of the influence of grain shape on the mechanical behaviour of granular materials
PublikacjaWe performed a series of numerical vertical compression tests on assemblies 01 20 granular material using a Discrete Element code and studied the results with regard to the grain shape. The samples consist of 5000 grains made from either 3 overlapping discs (clumps - grains with concavities) or six-edged polygons (convex grains). These two grain type have similar external envelope, which is a fund ion of a geometrical parameter...
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Chemical Theory of Machines, basic principles of strength with examples of calculations
PublikacjaThis book encompasses the essential range of information on technical aspects of mechanical design. It was written primarily for the students and staff of chemistry faculties of technical universities, yet it may also be utilized by everyone, who ether would like to try or already enjoys designing, but cannot take advantage of typical stress & machine construction handbooks. These handbooks often require familiarity with the concepts...
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The treatment of wastewater containing pharmaceuticals in microcosm constructed wetlands: the occurrence of integrons (int1–2) and associated resistance genes (sul1–3, qacEΔ1)
PublikacjaThe aim of this study was to analyze the occurrence of sulfonamide resistance genes (sul1–3) and other genetic elements as antiseptic resistance gene (qacEΔ1) and class 1 and class 2 integrons (int1–2) in the upper layer of substrate and in the effluent of microcosm constructed wetlands (CWs) treating artificial wastewater containing diclofenac and sulfamethoxazole (SMX), which is a sulfonamide antibiotic. The bacteria in the substrate...
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Możliwości wydłużania krzywych przejściowych w układach geometrycznych torów
PublikacjaW pracy przedstawiono analizę problemu wydłużania krzywych przejściowych, wykorzystując do tego celu analityczną metodę projektowania. Podstawę analizy stanowiły obliczenia numeryczne przeprowadzone dla zestawu parametrów charakteryzujących standardowy układ geometryczny: krzywa przejściowa – łuk kołowy – krzywa przejściowa (w wersji niesymetrycznej). Ocenie poddano różnice rzędnych poziomych układu istniejącego oraz układu z...
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Molecular Strategy for Survival at a Critical High Temperature in Eschierichia coli
PublikacjaThe molecular mechanism supporting survival at a critical high temperature (CHT) in Escherichia coli was investigated. Genome-wide screening with a single-gene knockout library provided a list of genes indispensable for growth at 47°C, called thermotolerant genes. Genes for which expression was affected by exposure to CHT were identified by DNA chip analysis. Unexpectedly, the former contents did not overlap with the latter except...
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Behaviour of deformed steel columns exposed to impact load during earthquakes: numerical analysis
PublikacjaIt has been observed during earthquakes that the so called soft-storey failure of an upper floor of a building leads to considerable vertical impact load acting on structural members of the lower storeys. The aim of this paper is to investigate numerically the behaviour of horizontally deformed columns (deformation as the result of earthquake loading) that are additionally subjected to vertical impact load. In the first stage of...
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Influence of laser processing of the low alloy medium carbon structural steel on the development of the fatigue crack
PublikacjaThe paper contains the results of the structural analysis, hardness tests and fatigue tests conducted for the medium carbon structural steel with low content of Cr and Ni after its processing with CO2 laser beam. Pre-cracks were made in the round compact tension (RCT) specimen used for fatigue test. Next, four paths, parallel to each other, were melted on both sides of the samples using a laser beam. The paths were perpendicular...
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Wpływ zaburzeń geometrii na proces wypierania w przestrzeni pierścieniowej otworów wiertniczych
PublikacjaIzolacja stref zbiornikowych, przenoszenie części naprężeń oraz spowolnienie tempa erozji rur okładzinowych to główne zadania płaszcza cementacyjnego. Powstaje on na skutek stopniowego wyparcia płuczki przez ciecze buforowe, a następnie cieczy buforowych przez zaczyn cementowy. Niepowodzenie tej operacji skutkować może katastrofą na miarę wycieku ropy w Zatoce Meksykańskiej w 2010 roku. Mimo że problem niewystarczającego związania płaszcza...
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A novel one-variable first-order shear deformation theory for biaxial buckling of a size-dependent plate based on Eringen’s nonlocal differential law
PublikacjaPurpose – This paper aims to present a new one-variable first-order shear deformation theory (OVFSDT) using nonlocal elasticity concepts for buckling of graphene sheets. Design/methodology/approach – The FSDT had errors in its assumptions owing to the assumption of constant shear stress distribution along the thickness of the plate, even though by using the shear correction factor (SCF), it has been slightly corrected, the errors...
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FEM modelling of screw displacement pile interaction with subsoil
PublikacjaPredicting the-settlement characteristics of piles is an important element in the designing of pile foundations. The most reliable method in evaluating pile-soil interaction is the static load test, preferably performed with instrumentation for measuring shaft and pile base resistances. This, however, is a mostly post-implementation test. In the design phase, prediction methods are needed, in which numerical simulations play an...
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Earthquake–induced pounding on response of adjacent structures in series: experimental and numerical study
PublikacjaPounding between structures in series during earthquakes may cause serious damage in the structur-al elements. The aim of this paper is to show the results of an experimental and numerical study that is focused on pounding between more than two structures which may be called "structures in series". In this study, the shaking table experiments, as well as the numerical analyses, were performed using three tower models including...
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Smart Virtual Product Development (SVPD) System to Support Product Inspection Planning in Industry 4.0
PublikacjaThis paper presents the idea of supporting product inspection planning process during the early stages of product life cycle for the experts working on product development. Aim of this research is to assist a collaborative product development process by using Smart Virtual Product Development (SVPD) system, which is based on Set of Experience Knowledge Structure (SOEKS) and Decisional DNA (DDNA). The proposed system is developed...
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The Influence of the Depth of Cut in Single-Pass Grinding on the Microstructure and Properties of the C45 Steel Surface Layer
PublikacjaThe paper contains the results of a metallographic examination and nanoindentation test conducted for the medium carbon structural steel with low content of Mn, Si, Cu, Cr, and Ni after its grinding to a depth ranging from 2 μm to 20 μm, at constant cutting speed (peripheral speed) of vs = 25 ms−1 and constant feed rate of vft = 1 m/min. Applied grinding parameters did not cause the surface layer hardening, which could generate...
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A new hyperbolic-polynomial higher-order elasticity theory for mechanics of thick FGM beams with imperfection in the material composition
PublikacjaA drawback to the material composition of thick functionally graded materials (FGM) beams is checked out in this research in conjunction with a novel hyperbolic‐polynomial higher‐order elasticity beam theory (HPET). The proposed beam model consists of a novel shape function for the distribution of shear stress deformation in the transverse coordinate. The beam theory also incorporates the stretching effect to present an indirect...
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A Concept for Safe and Less Expensive Acceleration of a Marine Steam Turbine Start-up
PublikacjaThis paper analyses the issue of accelerated start-up of a marine steam turbine, which is an important problem because the start-up of a steam machine involves the combustion of fuel that is not transformed into useful energy. To find novel technologies that offer improvements in this aspect is essential due to restrictions on reducing ship emissions. Thus, the shorter the start-up time, the better for the environment and economy....
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Linear viscoelastic transversely isotropic model based on the spectral decomposition of elasticity tensors
PublikacjaThe linear viscoelasticity is still a useful model in the engineering for studying the behavior of materials loaded with different loading rates (frequencies). Certain types of materials reveal also an anisotropic behavior: fiber reinforced composites, asphalt concrete mixtures, or wood, to name a few. In general, researchers try to identify experimentally the dependence of engineering constants like: directional Young’s moduli...
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Recent Advances in Loop Heat Pipes with Flat Evaporator
PublikacjaThe focus of this review is to present the current advances in Loop Heat Pipes (LHP) with flat evaporators, which address the current challenges to the wide implementation of the technology. A recent advance in LHP is the design of flat-shaped evaporators, which is better suited to the geometry of discretely mounted electronics components (microprocessors) and therefore negate the need for an additional transfer surface (saddle)...
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Fatigue fracture morphology of AISI H13 steel obtained by additive manufacturing
PublikacjaThe paper focuses on researching the effect of fatigue loading on metallic structure, lifetime, and fracture surface topographies in AISI H13 steel specimens obtained by selective laser melting (SLM). The topography of the fracture surfaces was measured over their entire area, according to the entire total area method, with an optical three-dimensional surface measurement system. The fatigue results of the SLM 3D printed steel...