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Search results for: ROTATIONAL CONTINUITY
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NEW DESIGNS OF CENTRIFUGAL MAGNETIC FLUID SEALS FOR ROTATING SHAFTS IN MARINE TECHNOLOGY
PublicationThe centrifugal magnetic fluid seals have important advantage over the conventional centrifugal seals. They maintain very good sealing capacity at static, medium and high speeds of shaft rotation, with the increased seal lifetime, and minimum torque and static friction. These seals are particularly useful in cases when the angular shaft velocity varies and sometimes decreases to nearly or exactly zero, such as in flywheel applications,...
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Longitudinally magnetized left-handed cylindrical ferrite coupled line junction for nonreciprocal devices
PublicationThis paper presents investigations of longitudinally magnetized left-handed cylindrical ferrite coupled line junction for nonreciprocal devices. The proposed junction is formed as a quasi periodic arrangement of N unit cells. Each unit cell is realized as a cascade of short cylindrical ferrite coupled lines with reactance circuit composed of series capacitors and parallel inductors. The left-handed cylindrical junction with π/4...
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Digital Fingerprinting Based on Quaternion Encryption Scheme for Gray-Tone Images
PublicationIn this paper a new idea of digital images fingerprinting is proposed. The method is based on quaternion encryption in the Cipher Block Chaining (CBC) mode. Quaternion sare hyper-complex numbers of rank 4 and thus often applied to mechanics in three-dimensional space. The encryption algorithm described in the paper is designed for gray-tone images but can easily be adopted for color ones. For the encryption purpose, the algorithm...
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<i>N,N,N</i>-Trimethyl-N-(methyl 5-deoxy-2,3-<i>O</i>-isopropylidene-β-D-ribofuranosid-5- yl)ammonium 4-methylbenzenesulfonate sesquihydrate.
PublicationThe structure of the title compound, [C12H24NO4][C7H7O3S]·1.5H2O, contains alternating layers parallel to (001) of hydrophobic and polar character, stabilized by C-H...O hydrogen bonding. The furan ring adopts an envelope conformation with the C(OMe) atom as the flap, and the dioxolane ring is twisted about one of the O-C(methine) bonds. A comparison to related compounds is presented. The tosylate-O atoms were disordered over two...
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The Application of Fluidic Sealing in Shrouded Gas Turbine Blades
PublicationThis paper presents a study conducted on a new gas turbine designed to limit leakage in the labyrinth seal. The slots in the fin are used to generate a bypass flow, which obstructs the flow in the gap above the fin. The method was tested numerically and experimentally beforehand using a simplified model without rotation or blade passages. In this paper, the validation of the method using a model of a turbine stage is shown. Reynolds-averaged...
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Knowledge base views
PublicationThe paper introduces an extension to the NeeK language. In the current shape NeeK allows for selection of fragments of a given ontology. The selected part is automatically mapped to a database schema by Data Views implementation. Experience with a real system using Data Views has shown that the resulting database schema does not necessarily reflect the needs of the business logic of an application that uses a specific Data View....
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Fragmentation of Tetrahydrofuran Molecules by H+, C+, and O+ Collisions at the Incident Energy Range of 25–1000 eV
PublicationWe have studied fragmentation processes of the gas-phase tetrahydrofuran (THF) molecules in collisions with the H+, C+, and O+ cations. The collision energies have been varied between 25 and 1000 eV and thus covered a velocity range from 10 to 440 km/s. The following excited neutral fragments of THF have been observed: the atomic hydrogen H(n), n = 4–9, carbon atoms in the 2p3s 1P1, 2p4p 1D2, and 2p4p 3P states and vibrationally...
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Projekt Leonardo da Vinci EMDEL (European Model for Distance Education and Learning) - otwarte szkolenia online.
PublicationW referacie zaprezentowano główne zadania oraz ofertę szkoleniową Centrum Edukacji Niestacjonarnej Politechniki Gdańskiej (CEN PG) w kontekście realizowanych projektów Unii Europejskiej. Przedstawiono projekt Leonardo da Vinci EMDEL - European Model for Distance Education and learning - realizowany przez CEN PG w latach 2001-2005 oraz opisano doświadczenia w zakresie adaptacji i lokalizacji opracowanych przez partnerów projektu...
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Działania intuicyjne w praktyce przedsiębiorczej
PublicationIntuicję definiuje się jako szybkie, nieświadome i holistyczne przeczucie, które jest dynamicznym procesem poznawczym opartym na doświadczeniu i wiedzy przedsiębiorcy. Intuicja pozwala rozpoznawać okazje biznesowe i uzupełnia racjonalne podejmowanie decyzji biznesowych. Korzystanie z intuicji jest wskazane szczególnie ze względu na permanentnie zmieniające się otoczenie prowadzenia firmy oraz duży poziom niepewności, towarzyszący...
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Optimization-based antenna miniaturization using adaptively-adjusted penalty factors
PublicationThe continuing trend for miniaturization of electronic devices necessitates size reduction of the comprising components and circuitry. Specifically, integrated circuit-antenna modules therein require compact radiators in applications such as 5G communications, implantable and on-body devices, or internet of things (IoT). The conflict between the demands for compact size and elec-trical and field performance can be mitigated by...
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Micro-modelling of shear localization during quasi-static confined granular flow in silos using DEM
PublicationThe paper deals with the quasi-static confined flow of cohesionless sand in a plane strain model silo with parallel walls and a slowly movable bottom. Numerical modelling was carried out by the discrete element method (DEM) using spheres with contact moments to approximately capture a non-uniform shape of sand particles. Different initial void ratios of sand and silo wall roughness grades were employed. Regular triangular grooves...
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EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF CONCRETE BEHAVIOUR AT MESO-LEVEL DURING QUASI-STATIC SPLITTING TENSION
PublicationThe paper describes experimental and numerical results of quasi-static splitting tensile tests on concrete specimens at meso-scale level. The loading strip was made of plywood or steel. Fracture in concrete was detected at the aggregate level by means of three non-destructive methods: 3D x-ray micro-computed tomography, 2D scanning electron microscope and manual 2D digital microscope. The discrete element method was used to directly...
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Reduction of measurement data before Digital Terrain Model generation vs. DTM generalisation
PublicationModern data acquisition technologies provide large datasets that are not always necessary in its entirety to properly accomplish the goal of the study. In addition, such datasets are often cumbersome for rational processing, and their processing is time and labour consuming. Therefore, methods that enable to reduce the size of the measurement dataset, such as the generalization of the Digital Terrain Model (DTM) or the reduction...
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Synthetic strategies in construction of organic macromolecular carrier–drug conjugates
PublicationMany metabolic inhibitors, considered potential antimicrobial or anticancer drug candidates, exhibit verylimited ability to cross the biological membranes of target cells. The restricted cellular penetration ofthose molecules is often due to their highhydrophilicity. One of the possible solutions to this problem is aconjugation of an inhibitor with a molecular organic nanocarrier. The conjugate thus formed should beable to penetrate...
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Experimental and Machine-Learning-Assisted Design of Pharmaceutically Acceptable Deep Eutectic Solvents for the Solubility Improvement of Non-Selective COX Inhibitors Ibuprofen and Ketoprofen
PublicationDeep eutectic solvents (DESs) are commonly used in pharmaceutical applications as excellent solubilizers of active substances. This study investigated the tuning of ibuprofen and ketoprofen solubility utilizing DESs containing choline chloride or betaine as hydrogen bond acceptors and various polyols (ethylene glycol, diethylene glycol, triethylene glycol, glycerol, 1,2-propanediol, 1,3-butanediol) as hydrogen bond donors. Experimental...
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Experimental and Machine-Learning-Assisted Design of Pharmaceutically Acceptable Deep Eutectic Solvents for the Solubility Improvement of Non-Selective COX Inhibitors Ibuprofen and Ketoprofen
PublicationDeep eutectic solvents (DESs) are commonly used in pharmaceutical applications as excellent solubilizers of active substances. This study investigated the tuning of ibuprofen and ketoprofen solubility utilizing DESs containing choline chloride or betaine as hydrogen bond acceptors and various polyols (ethylene glycol, diethylene glycol, triethylene glycol, glycerol, 1,2-propanediol, 1,3-butanediol) as hydrogen bond donors. Experimental...
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On jump conditions at non-material singular curves in the resultant shell thermomechanics
PublicationThe global, refined, resultant, two-dimensional (2D) balance laws of mass, linear and angular momenta, and energy as well as the entropy inequality were formulated by Pietraszkiewicz (2011) as exact implications of corresponding laws of 3D rational thermomechanics. In case of a shell with the regular base surface and all resultant surface fields differentiable everywhere on it and at any time instant, the local laws of the resultant...
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Połączenie G3 dwóch kierunków prostych z użyciem krzywej NURBS
PublicationW artykule przedstawiono nową metodę projektowania układu geometrycznego toru kolejowego opartą na zastosowaniu krzywych NURBS (Non-Uniform Rational B-Spline) do opisu krzywizny. Punkty kontrolne krzywej NURBS wyznaczane są w procesie optymalizacji za pomocą algorytmu genetycznego. Jako kryterium optymalizacji przyjęto minimalizację oddziaływań dynamicznych występujących w układzie tor-pojazd przy spełnieniu warunków geometrycznych...
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THE MODELLING OF ACCUMULATION AND DISSIPATION OF ENERGY IN MECHANICAL DRIVE SYSTEM
PublicationThis paper presents a modelling of accumulation and dissipation energy in simple drive system. The simple drive system is presented by laboratory stand designed for calculate fatigue life of material for bending and rotation tests pieces. The laboratory stand was prepared to diagnosis of fatigue life of material by use energetic methods. This idea was submitted as utility model to Polish Patent Office. This laboratory stand gives...
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USEFULNESS OF SEMI-MARKOV PROCESSES AS MODELS OF THE OPERATION PROCESSES FOR MARINE MAIN ENGINES AND OTHER MACHINES OF SHIP POWER PLANTS
PublicationThe paper describes the properties of semi-Markov processes and the opportunities and benefits from their use as models of the operation processes for marine combustion engines and other machines of ship power plants. The emphasis is put on the importance of the theory of semi-Markov processes for development of the theory of marine combustion engines and other machines of ship power plants, as well as for development of the operational...
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The Matter of Decision-Making Control Over Operation Processes of Marine Power Plant Systems with the Use of their Models in the form of Semi-Markov Decision-Making Processes
PublicationThe article presents the possibility to control the real operation process of an arbitrary device installed in the marine power plant based on the four-state semi-Markov process, being the model of the process, which describes the transition process of operational states of the device and the transition process of its technical states. All these states are precisely defined for the ship main engine (SG). A hypothesis is proposed...
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Non-Coaxially Rotating Motion in Casson Martial along with Temperature and Concentration Gradients via First-Order Chemical Reaction
PublicationThe effect of non-coaxial rotation on the transport of mass subjected to first-order chemical reaction is studied analytically. The effects of thermal radiation, buoyancy, constructive and destructive chemical reactions along with Casson fluid in rotating frame are discussed. Time evolution of primary and secondary velocities, energy and solute particles are analyzed. The behavior of flow under the variation of intensity of magnetic...
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The Influence of Low-Temperature Disintegration on the Co-Fermentation Process of Distillation Residue and Waste-Activated Sludge
Publication: Innovative low-temperature disintegration (process temperature 55 ◦C and oxygen concentration 0.2 mg/dm3 ) can be an economically rational technology to intensifying energy production from renewable sources. The proposed process can achieve a degree of disintegration—under optimal conditions—of about 50%, which is excellent when compared with other methods of feed pre-treatment. The low-temperature disintegration of distillation...
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Application of linear buckling sensitivity analysis to economic design of cylindrical steel silos composed of corrugated sheets and columns
PublicationThe paper deals with global stability of steel cylindrical silos composed of corrugated walls and vertical columns with loads imposed by a bulk solid following Eurocode 1. The optimum silo design with respect to the steel weight was based on a sensitivity analysis method. The changes of silo column profiles at each design step were performed by means of influence lines for the buckling load factor due to the unit column bending...
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Open Strategy for Digital Business. Managing in ICT-Driven Environments
PublicationThis book offers the reader a novel perspective on how digital contexts and open strategy approaches – the act of opening up strategic initiatives beyond company managers to involve front-line employees, stakeholders, and entrepreneurs – are related. Going beyond the claim that digital media drives open strategy by containing a detailed analyses of the interrelations between the two, the authors examine how ICT have diffused globally...
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Structural and Dynamic Properties of Water within the Solvation Layer around Various Conformations of the Glycine-based Polypeptide
PublicationSeveral conformations of the solvated glycine-based polypeptides were investigated using molecular dynamics simulations. Some properties of water in the neighboring space around these molecules were investigated. It was found that water forms a well-defined layer—the first solvation shell—around the peptide molecule, and thickness of this layer is independent of the peptide structure and is equal to approximately 0.28 nm. Within...
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Combined partial denitrification/anammox process for nitrogen removal in wastewater treatment
PublicationRecently, the combined partial denitrification and anammox (PD/anammox) has received special attention as a viable alternative for N removal using organic matter present in municipal wastewater. In comparison with conventional nitrification-denitrification, PD/anammox provides enormous opportunities to achieve sustainable wastewater treatment due to the lack of dissolved oxygen (DO) demand, a smaller amount of organic carbon (C)...
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Satelitowy agregat pompowy
PublicationW artykule opisano najnowszą konstrukcję satelitowego agregatu pompowego charakteryzującego się tym, że pompa satelitowa jest umieszczona wewnątrz silnika elektrycznego i zasysa ciecz poprzez otwór wydrążony osiowo w wale silnika. Zastosowana w agregacie pompa satelitowa jest nowatorską konstrukcją zawierającą mechanizm satelitowy o odwróconej kinematyce znamienny tym, że planeta (wirnik) oraz płyty kompensacyjne (rozrządu) są...
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Wybrane aspekty oceny satysfakcji i lojalności klientów i pracowników
PublicationCelem artykułu jest przedstawienie propozycji oryginalnego modelu pozwalającego lepiej zrozumieć mechanizmy kształtowania się satysfakcji i lojalności klientów i pracowników oraz umożliwiającego porównywanie satysfakcji klientów różnych przedsiębiorstw w oderwaniu od ich specyfiki branżowej. Zaprezentowany model opiera się na mechanizmach przyczynowo-skutkowych i pozwala na stawianie kwantyfikowalnych celów, dając w rezultacie...
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Big Data i 5V – nowe wyzwania w świecie danych (Big Data and 5V – New Challenges in the World of Data)
PublicationRodzaje danych, składające się na zbiory typu Big Data, to m.in. dane generowane przez użytkowników portali internetowych, dane opisujące transakcje dokonywane poprzez Internet, dane naukowe (biologiczne, astronomiczne, pomiary fizyczne itp.), dane generowane przez roboty w wyniku automatycznego przeszukiwania przez nie Internetu (Web mining, Web crawling), dane grafowe obrazujące powiązania pomiędzy stronami WWW itd. Zazwyczaj,...
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Schronienie – poszukiwanie formuły dla domu wpisanego w relacje środowiskowe
PublicationKonieczność schronienia i potrzeba zamieszkiwania wymagają przestrzeni, które współcześnie zazwyczaj zabezpieczają obiekty architektoniczne. Jednak często zauważamy niedobory wartości w przestrzeni zamieszkiwania. Pomysłem zaradczym w tej sytuacji jest powrót do punktu wyjścia. Do zapewnienia schronienia. Jeśli będzie ono wpisane w relacje środowiskowe i ukształtowane w zgodzie z potrzebą zachowania ciągłości kulturowej, ma szansę...
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Nonlinear finite element modeling of vibration control of plane rod-type structural members with integrated piezoelectric patches
PublicationThis paper addresses modeling and finite element analysis of the transient large-amplitude vibration response of thin rod-type structures (e.g., plane curved beams, arches, ring shells) and its control by integrated piezoelectric layers. A geometrically nonlinear finite beam element for the analysis of piezolaminated structures is developed that is based on the Bernoulli hypothesis and the assumptions of small strains and finite...
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Secure Quaternion Feistel Cipher for DICOM Images
PublicationAn improved and extended version of a quaternion-based lossless encryption technique for digital image and communication on medicine (DICOM) images is proposed. We highlight and address several security flaws present in the previous version of the algorithm originally proposed by Dzwonkowski et al. (2015). The newly proposed secure quater- nion Feistel cipher (S-QFC) algorithm...
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New concept of drilling auger for displacement pile installation
PublicationIn 2020, a new version of the screw displacement auger for pile installation in soil was developed and patented in Poland. It was named DPDT (Displacement Pile Drilling Tool). The general aim of its development was to reduce the soil resistances to the auger during screwing into the ground while maintaning a good load-bearing capacity for the screw displacement piles. The “DPDT-Auger” prototype was tested as a scaled-down model...
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Local buckling of composite channel columns
PublicationThe investigation concerns local buckling of compressed flanges of axially compressed composite channel columns. Cooperation of the member flange and web is taken into account here. The buckling mode of the member flange is defined by rotation angle a flange about the line of its connection with the web. The channel column under investigation is made of unidirectional fibre-reinforced laminate. Two approaches to member orthotropic...
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Recent Achievements in Constitutive Equations of Laminates and Functionally Graded Structures Formulated in the Resultant Nonlinear Shell Theory
PublicationThe development of constitutive equations formulated in the resultant nonlinear shell theory is presented. The specific features of the present shell theory are drilling rotation naturally included in the formulation and asymmetric measures of strains and stress resultants. The special attention in the chapter is given to recent achievements: progressive failure analysis of laminated shells and elastoplastic constitutive relation...
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Influence of the femoral offset on the muscles passive resistance in total hip arthroplasty
PublicationBackground Soft tissue tension is treated as a crucial factor influencing the post-THA dislocation. The femoral offset is regarded as one of the major parameters responsible for the stabilization of the prosthesis. It is unclear which soft tissue is mostly affected by the offset changes. Methods A finite element model of the hip was created. The model comprised muscles, bones, a stem, the acetabular component and a liner. The muscles...
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Two-particle entropy and structural ordering in liquid water
PublicationEntropies of simple point charge (SPC) water were calculated over the temperature range 278-363 K using the two-particle correlation function approximation. Then, the total two-particle contribution to the entropy of the system was divided into three parts, which we call translational, configurational, and orientational. The configurational term describes the contribution to entropy, which originates from spatial distribution of...
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Heat transfer characteristics of hybrid microjet – Microchannel cooling module
PublicationThe paper presents experimental investigation of heat transfer intensification in a microjet–microchannel cooling module. Applied technology takes benefits from two very attractive heat removal techniques. When jets are impinging on the surface, they have a very high kinetic energy at the stagnation point, also in microchannels boundary layer is very thin allowing to obtain very high heat fluxes. Main objective of this paper was...
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Comparison of heat transfer characteristics in surface cooling with boiling microjets of water, ethanol and HFE7100
PublicationThe basis of microjet technology is to produce jets which impinge the surface at the stagnation point with a very high kinetic energy. Main objective of this paper was to investigate the physical phenomena occurring on solid surfaces upon impingement of the single microjet in case of three fluids, namely water, ethanol and HFE7100. Intense heat transfer in the impact zone of microjet has been examined and described with precise...
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Modeling a Traffic Remapping Attack Game in a Multi-hop Ad Hoc Network
PublicationIn multi-hop ad hoc networks, selfish nodes may unduly acquire high quality of service (QoS) by assigning higher priority to source packets and lower priority to transit packets. Such traffic remapping attacks (TRAs) are cheap to launch, impossible to prevent, hard to detect, and harmful to non-selfish nodes. While studied mostly in single-hop wireless network settings, TRAs have resisted analysis in multi-hop settings. In this paper...
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Experimental and theoretical study on high-temperature creep of VT6 titanium alloy under multi-axial loading conditions
PublicationIn the framework of damage mechanics, we discuss a new mathematical model that describes the kinetics of the stress–strain state and damage accumulation during material degradation by the mechanism of long-term strength under complex multiaxial stress state. An experimental and theoretical technique is proposed for determination of material parameters and scalar constitutive functions for damaged media based on specially set experiments...
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Is the Concept of Zero Waste Possible to Implement in Construction?
PublicationThe scientifically treated problem of reusing building materials appeared in the literature more than 50 years ago. This paper includes an analysis of the characteristics of recycled building materials, which is a prerequisite for rational recycling. The analysis and simulation of building stocks at different scales has led to the conclusion that the most important link in the transformation of the construction industry towards...
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Modelling and Analysis of the Positioning Accuracy in the Loading Systems of Mobile Cranes
PublicationIn this work, the authors analyse the influence of the order and range of sequential movements of a crane's working members on the accuracy of the final cargo positioning. The analysis was conducted on the basis of a specially developed method in which the authors proposed the introduction of a geometrical indicator of positioning the load in the intermediate positions (after completing each movement sequence) and in the target...
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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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Determinants of Directionality and Efficiency of the ATP Synthase Fo Motor at Atomic Resolution
PublicationFo subcomplex of ATP synthase is a membrane-embedded rotary motor that converts proton motive force into mechanical energy. Despite a rapid increase in the number of high-resolution structures, the mechanism of tight coupling between proton transport and motion of the rotary c-ring remains elusive. Here, using extensive all-atom free energy simulations, we show how the motor’s directionality naturally arises from the interplay...
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Correlation–polarization effects in electron/positron scattering from acetylene: A comparison of computational models
PublicationDifferent computational methods are employed to evaluate elastic (rotationally summed) integral and differential cross sections for low energy (below about 10 eV) positron scattering off gas-phase C2H2 molecules. The computations are carried out at the static and static-plus-polarization levels for describing the interaction forces and the correlation–polarization contributions are found to be an essential component for the correct...
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Personal Brand Value and Social Media, the Top Football Players’ Case
PublicationPersonal branding valuation and social media usage are new and empirically unexplored areas of research. The aim of the presented study is to determine how social media performance and sentiment are related to the value of a personal brand. Based on an example of 100 most valuable football players, in reference to transfermarkt.com and the sentione.com (sentiment analysis), the author points out the strongest...
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WZROST ZATRUDNIENIA W PRZEDSIĘBIORSTWACH MSP problemy badawcze i wyniki
PublicationW artykule w pierwszej kolejności przedstawiono główne problemy badawcze związane z zagadnieniem wzrostu i rozwoju przedsiębiorstwa, wskazując na najczęściej stosowane rozwiązania metodyczne w tym zakresie. W dalszej części zaprezentowano wyniki badań empirycznych, dotyczące zmian zatrudnienia oraz planów związanych z rozwojem małych i średnich przedsiębiorstw funkcjonujących na Pomorzu (badania zostały przeprowadzone w 2009 i...
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Scale effect in the self-propulsion prediction for Ultra Large Container Ship with contra-rotating propellers
PublicationThis article addresses the problem of the scale effect for an Ultra Large Container Ship (ULCS) with a novel twin-crp-pod propulsion system. Twin-crp-pod steering-propulsion arrangement is an innovative solution that gains from three well-known systems: twin-propeller, contra-rotating propellers and pod propulsors. It is expected that applying the twin-crp-pod system to the analysed Ultra Large Container Ship will increase propulsion...