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Search results for: INDUSTRY ANALYSIS, FIVE FORCES, SIX FORCES
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Selected aspects of the evolution of the industry analysis
PublicationPorter's five forces is a significant tool of analysis of industries. It helps evaluating variables of industry profitability and assessing firm performance. Using the framework, managers can take a decision as to which industries they can effectively compete in and position their companies to reduce the adverse effects of the mentioned forces. According to the critics, the five forces model is limited to its static nature. The...
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Scientific Journal of the Military University of Land Forces
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Analysis of unsteady flow forces on the thermowell of steam temperature sensor
PublicationIn this paper, 3D numerical analysis of unsteady flow forces acting on the measuring sheath of steam temperature is presented. According to that purpose, the CFD (Computation Fluid Dynamic [1]) approach has been used. The nonstationary of fluid acting on the measuring sheath such as: Strouhal frequency, amplitude of pressure, structure of vortex, peak of pressure, field of pressure, field of velocity etc. are studied analytically...
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Forces in Mechanics
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Social Forces
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Stan graniczny nośności dźwigara żelbetowego mostu na zginanie według norm PN-EN 1992-2 oraz PN-S-10042:1991
PublicationPraca włącza się w bogaty w ostatnich latach w krajowym piśmiennictwie nurt porównań dwóch generacji norm projektowania mostów z betonu: polskiej - wycofanej, aczkolwiek powszechnie stosowanej oraz europejskiej – wciąż jeszcze wdrażanej do praktyki projektowej. Nowością w stosunku do dotychczasowych publikacji polskich jest szersze ujęcie różnic pomiędzy obydwiema generacjami norm. Poza rozpatrywanymi przez wielu autorów różnicami...
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Explanation of Reduction of Pressure Forces in Turbine Chamber Seals
PublicationThe paper describes a chamber seal reducing the aerodynamic forces created in shroud seals. Asymmetrical pressure distribution (due to rotor-stator eccentricity) in the blade tip clearance leads to the creation of pressure forces acting on the blade shroud. By increasing the volume above the shroud, the pressure distribution becomes more uniform on the whole shroud circumference and the effect of rotor eccentricity is reduced....
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Explanation of Reduction of Pressure Forces in Turbine Chamber Seals
PublicationThe paper describes a chamber seal reducing the aerodynamic forces created in shroud seals. Asymmetrical pressure distribution (due to rotor-stator eccentricity) in the blade tip clearance leads to the creation of pressure forces acting on the blade shroud. By increasing the volume above the shroud, the pressure distribution becomes more uniform on the whole shroud circumference and the effect of rotor eccentricity is reduced....
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Is It Right To Predict Cutting Forces On The Basis Of Wood Density?
PublicationSeveral properties of wood can be correlated to wood density. It is widely accepted that the cutting power requirements are following this general assumption. Therefore, according to classic literature sources available for determination of the cutting power for both band- and circular- sawing machines, the cutting power requirements (and/or cutting forces) are computed as a function of the wood specific gravity SG. It was shown...
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Analysis of compressive forces in CFGFT cylindrical pillars and their coatings using laboratory tests and metric spaces
PublicationThe article discusses compressive forces tests in composite-concrete pillars with the use of laboratory active experiment including the factors and properties of materials which have a significant impact on the test results and their repeatability. A polymer composite based on glass fiber reinforced resin with different fiber beam angles (20, 55 and 85) was used as a buffer/coat of the pole. Due to the problems with direct comparison...
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Manoeuvring forces on azimuthing podded propulsor model
PublicationThis paper presents the preliminary part of comprehensive manoeuvring open- water tests of a gas carrier model. The paper focuses on open water experiments with an azimuthing podded propulsor. The test program was carried out in the cavitation tunnel and the large towing tank of Ship Hydromechanics Division, Ship Design and Research Centre, Gdańsk. The pod was tested as a pushing unit with a 161.3 mm diameter propeller. Steering...
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Influence of the shoe type on the ground reaction forces
PublicationThe aim of this work was to estimate a relationship between the type of the footwear and ground reactions. Differences in medio-lateral, anterior-posterior and vertical reactions are compared for different shoe-types for male and female volunteers. Each of the participants gait was recorded in case of different shoes and without them, also stabilograms were analyzed. Results revealed differences in ground reaction forces for different...
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EXPERIMENTAL AND THEORETICAL FLOW OF THE FORCES IN DEEP BEAMS WITH CANTILEVAR
PublicationThis article presents the results of experimental research carried out on deep beams with cantilever which was loaded throughout the depth. The main deep beam was directly simply supported on the one side. On the other side the deep beam was suspended in another deep member situated at right angles. All deep beams created a spatial arrangement. The paper is focused on the analysis of the cracks morphology and flow of the internal...
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The Method of reduction of aerodynamic forces generated in turbine blade seals
PublicationThe distibution of pressure in the seal gaps does not only affect the so called '' leakage losses'' and the turbine stage overall efficiency but also plays an important role in the generation of aerodynamic forces which may cause self-excited rotor vibrations. The paper describes a chamber seal applied for the reduction of the aerodynamic forces created in shroud seals. This kind of turbine seal was patented and tested.
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Stabilizing forces in trapezoidal sheeting used as a part of the bracing system
PublicationIn the analysis of bracing systems imperfections of the restrained elements should be considered. According to EC3 this effect can be calculated by means of the equivalent stabilizing force, which replaces (in simplified way) initial bow imperfection of the braced element. However, alternative suggestions of the equivalent stabilizing force calculations can be also found in the literature. In this paper segment of the pitched roof...
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Stabilizing forces in trapezoidal sheeting used as a part of the bracing system
PublicationIn the analysis of bracing systems imperfections of the restrained elements should be considered. According to EC3 this effect can be calculated by means of the equivalent stabilizing force, which replaces (in simplified way) initial bow imperfection of the braced element. However, alternative suggestions of the equivalent stabilizing force calculations can be also found in the literature. In this paper segment of the pitched roof...
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Analysis of the relationship between cutting forces and local structural properties of Scots pine wood aided by computed tomography
PublicationX-ray computed tomography (CT) is utilised in some sawmills today, primarily for enhancing value yield and for process automation, which includes log sorting and sawing optimisation. Nevertheless, there is a scarcity of recent research utilising CT to assess the local cutting process. As a preliminary study, this paper addresses this gap by using CT to investigate the connections between local cutting force and local wood properties...
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The concept of capillary forces supported evaporator for application to domestic ORC unit
PublicationIn the paper presented are studies on the investigation of the capillary forces effect inducted in the porous structure of a loop heat pipe. The potential application of such heat exchanger is for example an evaporator of the domestic micro CHP unit. Preliminary analysis of the results indicates water as having the best potential, however taking into account all issues it can be said that the best effect is obtained using ethanol.
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Sensitivity analysis of critical forces of trusses with side bracing
PublicationThe present research is devoted to the study of out-of-plane buckling of trusses with elastic side bracing. Inthis paper, a sensitivity analysis of critical buckling loads of a truss due to bracing stiffness is carried out. A method based on the sensitivity analysis for the determination of the threshold bracing stiffness conditionfor full bracing of a truss is proposed. The influence lines of the unit change of the bracing stiffness...
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The analysis of hydrodynamic forces and shape of towrope for an underwater vehicle
PublicationOpisano metodę obliczania sił hydrodynamicznych oraz kształtu liny holującej pojazd podwodny pod wpływem sił indukowanych przez opływ wody wokół liny i pojazdu. Siły indukowane na linie obliczane są za pomocą równania Morison'a, natomiast siły i momenty na kadłubie pojazdu za pomocą współczynników sił hydrodynamicznych, zależnych od kątów natarcia i prękości holowania pojazdu. Przykłady obliczeń dla pojazdu podwodnego zostały wykonane...
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Multimodal analysis of traction forces and the temperature dynamics of living cells with a diamond-embedded substrate
PublicationCells and tissues are constantly exposed to chemical and physical signals that regulate physiological and pathological processes. This study explores the integration of two biophysical methods: traction force microscopy (TFM) and optically detected magnetic resonance (ODMR) to concurrently assess cellular traction forces and the local relative temperature. We present a novel elastic substrate with embedded nitrogen-vacancy microdiamonds...
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Influence of the Shear Cap Size and Stiffness on the Distribution of Shear Forces in Flat Slabs
PublicationThe scope of this paper is to investigate analytically and numerically the influence of shear cap size and stiffness on the distribution of shear forces in flat slabs in a slab–column-connections-reinforced concrete structure. The effect of support (shear cap) stiffness on the calculation of the length of the shear control perimeter according to the available methods is presented. Based on the analysis, the authors indicate in...
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Design and Evaluation of the Platform for Weight-Shifting Exercises with Compensatory Forces Monitoring
PublicationDetails of a platform for the rehabilitation of people with severe balance impairment are discussed in the paper. Based upon a commercially available static parapodium, modified to fit force sensors, this device is designed to give a new, safe tool to physiotherapists. It is designed for the patients who cannot maintain equilibrium during a bipedal stance and need to hold to or lean on something during the rehabilitation. Visual,...
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ARMED FORCES & SOCIETY
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Deformation of an elastic second gradient spherical body under equatorial line density of dead forces
PublicationWe consider deformations of an elastic body having initially a spherical shape. Assumed deformation energy depends on the first and second gradient of displacements. We apply an equatorial line density of dead loads, that are forces per unit line length directed in radial direction and applied along the equator of the sphere. We restrict ourselves our analysis to the case of linearized second strain gradient isotropic elasticity...
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Driving forces of informal employment: An empirical study based on Polish enterprise data
PublicationObjective: The article aims to indicate the determinants of informal employment in registered enterprises using company-level evidence from Poland. Research Design & Methods: The survey conducted among Polish small and medium-sized (SME) enterprises in 2018 was used to find the driving forces of informal employment in Poland. The adequate sample comprised 952 representative surveys derived from the computer-assisted telephone...
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The new concept of capillary forces aided evaporator for application in domestic organic rankine cycle
PublicationThis paper presents studies on the possibility of applying capillary forces induced in the porous structure to a modern design of evaporator. The potential application of such heat exchanger is for example an evaporator of the domestic micro combined heat and power (CHP) unit. One of the problems in the micro-CHP is excessive demand for pumping power. The proposed design helps in overcoming that issue. In the evaporator outlined...
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The Influence of External Additional Loading on the Muscle Activity and Ground Reaction Forces during Gait
PublicationAsymmetrical external loading acting on the usculoskeletal system is generally considered unhealthy. Despite this knowledge, carrying loads in an asymmetrical manner like carrying on one shoulder, with one hand, or on the strap across the torso is a common practice. This study is aimed at presenting the effects of the mentioned load carrying methods on muscle activity assessed by using thermal field and ground reaction forces....
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The Effect of Wood Provenance and Density on Cutting Forces While Sawing Scots Pine (Pinus sylvestris L.)
PublicationSeveral properties of wood including the cutting power requirements can be correlated to wood density. Therefore, according to the literature, the cutting power requirements (and/or cutting forces) could be computed as a function of the wood specific gravity. This research shows that such an approach, based solely on specific gravity, may be considered a rather rough and imperfect estimate of cutting power. Samples of Scots pine...
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AN ALTERNATIVE WAY OF DETERMINING MECHANICAL PROPERTIES OF WOOD BY MEASURING CUTTING FORCES
PublicationThe cutting force is an energetic effect of splitting material, and might be therefore considered from a point of view of modern fracture mechanics. The dedicated mathematical model developed for description of the wood cutting has been developed here on the base of fracture theory, and includes work of separation (fracture toughness) in addition to the material plasticity and friction. The effect of the cutting edge dullness is...
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Assessment of tensile forces in Sopot Forest Opera membrane by in situ measurements and iterative numerical strategy for inverse problem
PublicationAssessment of tensile forces in newly build Sopot Forest Opera roofing membrane is presented. The procedure is based on in situ measurements and solution of the inverse problem by an iterative procedure. The goal of the analysis is to determine whether the stress state of the membrane is consistent with the design assumptions. The paper contains the description of measurements, used instruments, applied loadings, numerical investiga-tions...
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The differential impact of a density of Polish pine wood on cutting forces with its origin region taken into consideration
PublicationIn the article the dependence of cutting forces in a function the density of wood with regard to the wood origin are presented. Samples used in experiment were with Scotch pine (Pinus sylvestris L.) originating from four provenances in Poland (Figure 1). Wood density was measured by two methods: stereometric method (global density) and radiometric method (local density). Stereometric method consists in measurements the volume...
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Lateral forces determine dimensional accuracy of the narrow‑kerf sawing of wood
PublicationThe shrinking global forest area limits the supply of industrially usable raw resources. This, in combination with the ever‑increasing consumption of timber due to population growth can lead to the lack of a positive balance between the annual volumetric growth and consumption of wood. An important innovation toward increasing environmental and economic sustainability of timber production is to reduce the volume of wood residues...
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Time Domain Modeling of Propeller Forces due to Ventilation in Static and Dynamic Conditions
PublicationThis paper presents experimental and theoretical studies on the dynamic effect on the propeller loading due to ventilation by using a simulation model that generates a time domain solution for propeller forces in varying operational conditions. For ventilation modeling, the simulation model applies a formula based on the idea that the change in lift coefficient due to ventilation computes the change in the thrust coefficient. It...
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3D calculations of aerodynamic forces causing self-excited vibrations of turbine rotor systems. Part II: Pressure forces
PublicationPrzedstawiono wyniki badań numerycznych sił generowanych w uszczelnieniu nadbandażowym stopnia turbinowego przeprowadzone metodą Fluent. Uwzględniono niecentryczne położenie osi wirnika względem osi korpusu. Rozpatrzono bandaże o różnej geometrii. Niektóre wyniki zweryfikowano doświadczalnie.
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Methods of determining cutting forces during woodcutting
PublicationW artykule przedstawiono podstawowe metody określania sił przy przecinaniu drewna, które ulegały modyfikacjom wraz z postępem wynikającym z badań nad tym procesem. Przedstawione metody podzielono na dwie grupy: podejście klasyczne oraz nowatorskie podejście z zastosowaniem mechaniki pękania, które uwzględniają różne własności mające wpływ na proces przecinania. Podejście klasyczne reprezentują metody opierające się na właściwym...
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Isomerization and Decomposition of 2-Methylfuran with External Forces
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Reduction of pressure forces in turbine labyrinth seals
PublicationPrzedstawiono nową metodę zmniejszani sił samowzbudnych typu aerodynamicznego. zastosowano ją do różnych typów nadbandażowych uszczelnień labiryntowych. Efektywność rdukcji sił samowzbudnych wynosiła nawet ponad 60%. Potwierdzone rezultay obliczeniami i eksperymentalnie.
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On hydrodynamic forces acting on the ship in large motions.
PublicationPraca zapoznaje czytelnika ze współczesnym stanem dynamiki statku w nieliniowym ujęciu, ukierunkowanym na unikanie zbyt daleko idących komplikacji w rozwiązaniu. Nieliniowość dotyczy przede wszystkim sił Fronda-Kryłowa oraz sił tłumienia po wejściu pokładu do wody, czy też oporu stępek przechyłowych. Do pozostałych sił towarzyszących i dyfrakcyjnych stosuje się ekstrapolację podejścia liniowego.
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Evaluation of adhesive forces and the specific surface energy of zirconia stabilized by yttria with alumina additions ceramic by AFM method
PublicationThe adhesive forces and the specific surface energy of ceramic material surfaces are very important for further tribological and biomedical applications of ceramics. Partially stabilized zirconia (zirconium oxide) is popular for manufacturing various medical products. ZrO2 stabilized by Y2O3 with additions of 5 wt% alumina was produced by slip casting method with a subsequent sintering. Structure and chemical composition of ceramic...
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The influence of rotor-stator axial gap on the aerodynamic forces generatedin the shroud clearance of a turbine stage. Part II: Forces and moments
PublicationPrzedstawiono wyniki badań doświadczalnych wpływu zmiany luzu osiowego na wymuszenia aerodynamiczne powstające w uszczelnieniu nadbandażowym stopnia powietrznej turbiny modelowej. Wykazano, że w przypadku uszczelnienia promieniowego zmiana luzu osiowego odgrywa niewielką rolę w generowaniu sił i momentów aerodynamicznych w szczelinie nadbandażowej w porównaniu ze zmianą mimośrodowości czy skośnego ustawienia osi wirnika względem...
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Contr-rotating eccentric-mass rotors used as exciters of sinusoidal forces applied to elastically supported bodies
PublicationThe work focuses on aspects of multibody dynamics. Investigated object is a mass driven by rotations of an inertial shaker. Resulting vibrational set consists of two counter-rotating identically-unbalanced rotors. Since the mass centres of the rotors do not coincide with the axes of their rotations, significant centrifugal forces arise during rotations. As both rotors are identically unbalanced, the inter-axial force components...
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The methods of braking forces measurement for e mechanical vehicle
PublicationPrzedstawiono metody pomiaru sił hamowania pojazdów samochodowych.
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Simulation of the conformational flexibility of the mycodextran under external forces
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Experimental measurements of friction forces on the tissue in probabilistic view
PublicationNiniejsza praca jest poświęcona wyznaczaniu wartości sił tarcia wywołanych podczas hydrodynamicznego przepływu lepkosprężystej cieczy odżywczej na powierzchniach hodowanych chondrocytów w bioreaktorze. Badania realizuje się w nano skali przy wykorzystaniu mikroskopu sił atomowych. Chondrocyty hodujemy w celu naprawy uszkodzonych chrząstek stawowych kolana człowieka.
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A simple method for prediction of hydrodynamics forces on a pod propulsor
PublicationReferat przedstawia prostą metodę teoretyczną wyznaczania sił hydrodynamicznych na pędniku podowym przy różnych współczynnikach posuwu i kątach dryfu. Metoda jest oparta na elementarnej teorii płatów nośnych i na teorii pędnika idealnego. metoda ta jest podstawą dla programu komputerowego pozwalającego wyznaczać napór, siłę boczną i moment dla pędnika o znanej geometrii i znanych parametrach pracy. Rezultaty obliczeń są porównane...
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Analysis of stress and strains, forces and energy in initial contact zone abrasive grain with treating material
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Specific Binding of Cholesterol to the Amyloid Precursor Protein: Structure of the Complex and Driving Forces Characterized in Molecular Detail
PublicationC99 is the C-terminal membrane-bound fragment of the amyloid precursor protein that is cleaved by γ-secretase to release Aβ peptides, the hallmark of Alzheimer’s disease (AD). Specific interactions of C99 with cholesterol have been proposed to underlie the recognized role of cholesterol in promoting amyloidogenesis. By using molecular dynamics simulations, we studied cholesterol binding to C99 in a lipid bilayer. We determined...
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Report for the Short Term Scientific Mission within COST Action FP1101: development of the in-field sensor for estimation of fracture toughness and shear strength by measuring cutting forces
PublicationKnowledge on the fracture properties of materials is essential to assure structural integrity and proper design of mechanical connections in timber constructions. Measurement of this property is, however, a very challenging task. The linear fracture mechanics is usually used for its assessment assisted with experimental data acquired by means of various techniques, usually of destructive nature. The cutting force is an energetic...
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Investigation on the edge forces in ball end milling of inclined surfaces
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