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Search results for: external viscosity
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Quantum-state transfer in spin chains via isolated resonance of terminal spins
PublicationWe propose a quantum-state transfer protocol in a spin chain that requires only the control of the spins at the ends of the quantum wire. The protocol is to a large extent insensitive to inhomogeneity caused by local magnetic fields and perturbation of exchange couplings. Moreover, apart from the free evolution regime, it allows one to induce an adiabatic spin transfer, which provides the possibility of performing the transfer...
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The behavioural model of graphene field-effect transistor
PublicationThe behavioural model of a graphene field-effect transistor (GFET) is proposed. In this approach the GFET element is treated as a “black box” with only external terminals available and without considering the physical phenomena directly. The presented circuit model was constructed to reflect steady-states characteristics taking also into account GFET capacitances. The authors’ model is defined by a relatively small number of equations...
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Measurements and visualization of sound field distribution around organ pipe
PublicationMeasurements and visualization of acoustic field around an organ pipe are presented. Sound intensity technique was applied for this purpose. Measurements were performed in free field. The organ pipe was activated with a constant air flow, produced by an external compressor, aimed at obtaining long-term steady state responses of generated acoustic signal. Sound energy distribution was measured in a defined fixed grid of points...
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Standing Waves in One-Dimensional Resonator Contaning an Ideal Isothermal Gas Affected by the Constant Mass Force
PublicationThe study is devoted to standing acoustic waves in one-dimensional planar resonator which containing an ideal gas. A gas is affected by the constant mass force. Two types of physically justified boundary conditions are considered: zero velocity or zero excess pressure at both boundaries. The variety of nodal and antinodal points is determined. The conclusion is that the nodes of pressure and antinodes of velocity do not longer...
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Electromagnetic plane wave scattering from a cylindrical object with an arbitrary cross section using a hybrid technique
PublicationA hybrid technique combining finite-element and mode-matching methods for the analysis of scattering problems in open and closed areas is presented. The main idea of the analysis is based on the utilization of the finite-element method to calculate the post impedance matrix and combine it with external excitation. The discrete analysis, which is the most time- and memory-consuming, is limited here only to the close proximity of...
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Dynamically positioned ship steering making use of backstepping method and artificial neural networks
PublicationThe article discusses the issue of designing a dynamic ship positioning system making use of the adaptive vectorial backstepping method and RBF type arti cial neural networks. In the article, the backstepping controller is used to determine control laws and neural network weight adaptation laws. e arti cial neural network is applied at each time instant to approximate nonlinear functions containing parametric uncertainties....
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Variability of relationship between cities and nature in landscape architecture= Zmienność relacji miedzy miastem a naturą na przykładzie architektury krajobrazu miast
PublicationInterpreting and creating the relations between nature and city are the process of learning which is a subject of permanent conceptualization. It is characterized by the culutrality due to human nature and own ability to perceive oneself in the context of the relationship between own environmental and cultural nature. The way of interpreting the nature and providing it with different features affected significantly the development...
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Nonlinear Excitation of the Non-Wave Perturbations by the Magnetoacoustic Waves in the Non-Isentropic Plasma
PublicationNonlinear excitation of slow modes by the planar magnetosonic perturbations in a plasma is discussed. Plasma is an open system due to radiation and external heating. This may stipulate enhancement of wave perturbations and hence the acoustical activity of plasma. Plasma is assumed to be a homogeneous ideal gas with infinite electrical conductivity. The straight magnetic field is orthogonal to the velocity of fluid’s...
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Managing Quality Contests Based on Excellence Model at the Local Level. Selected Conditions and Problems – Case Study
PublicationThe aim of this article was to present characteristic phenomena accompanying competitions for quality awards based on the use of the organizational excellence models implemented at the regional level. Typical problems were identified, the understanding of which allows for a better use of the idea of excellence to raise the overall level of maturity of organizations aspiring to quality awards at every level. The results of self-assessment...
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Systems of boundary value problems of advanced differential equations
PublicationThis paper considers the existence of extremal solutions to systems of advanced differential equations with corresponding nonlinear boundary conditions. The monotone iterative method is applied to obtain the existence results. An example is provided for illustration.
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The paired-domination and the upper paired-domination numbers of graphs
PublicationIn this paper we obtain the upper bound for the upper paired-domination number and we determine the extremal graphs achieving this bound. Moreover we determine the upper paired- domination number for cycles.
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Possibility to use engine compression ignition engines in floating power plants marine
PublicationCompression-ignition engines used in ship technology as main propulsion engines are large units reaching even to 50-60 MW. The engines can be used in power industry for electricity generation in a simple or combined steam turbine system in combined heat and power plants. The leading engine in such an arrangement is an internal-combustion piston engine. The main propulsion engines are used in large piston internal-combustion engines...
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Novel binary mixtures of alkanolamine based deep eutectic solvents with water - thermodynamic calculation and correlation of crucial physicochemical properties
PublicationThis paper demonstrates the assessment of physicochemical and thermodynamic properties of aqueous solutions of novel deep eutectic solvent (DES) built of tetrabutylammonium chloride and 3-amino-1-propanol or tetrabutylammonium bromide and 3-amino-1-propanol or 2-(methylamino)ethanol or 2-(butylamino)ethanol. Densities, speeds of sound, refractive indices, and viscosities for both pure and aqueous mixtures of DES were investigated...
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Novel Binary Mixtures of Alkanolamine Based Deep Eutectic Solvents with Water—Thermodynamic Calculation and Correlation of Crucial Physicochemical Properties
PublicationThis paper demonstrates the assessment of physicochemical and thermodynamic properties of aqueous solutions of novel deep eutectic solvent (DES) built of tetrabutylammonium chloride and 3-amino-1-propanol or tetrabutylammonium bromide and 3-amino-1-propanol or 2-(methylamino)ethanol or 2-(butylamino)ethanol. Densities, speeds of sound, refractive indices, and viscosities for both pure and aqueous mixtures of DES were investigated...
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An isogeometric finite element formulation for boundary and shell viscoelasticity based on a multiplicative surface deformation split
PublicationThis work presents a numerical formulation to model isotropic viscoelastic material behavior for membranes and thin shells. The surface and the shell theory are formulated within a curvilinear coordinate system,which allows the representation of general surfaces and deformations. The kinematics follow from Kirchhoff–Love theory and the discretization makes use of isogeometric shape functions. A multiplicative split of the surface...
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Numerical analysis of the ostiomeatal complex aeration using the CFD method
PublicationWe aimed to analyse ostiomeatal complex (OMC) aeration using the computational fluid dynamics (CFD) method of simulation based on human craniofacial computed tomography (CT) scans. The analysis was based on CT images of 2 patients: one with normal nose anatomy and one with nasal septal deviation (NSD). The Reynolds-Average Simulation approach and turbulence model based on linear eddy viscosity supplemented with the two-equation...
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Copolymerization of Styrene and Pentadecylphenylmethacrylate (PDPMA): Synthesis, Characterization, Thermomechanical and Adhesion Properties
PublicationThe copolymerization of styrene (St) with a bioderived monomer, pentadecylphenylmethacrylate (PDPMA), via atom transfer radical polymerization (ATRP) was studied in this work.The copolymerization reactivity ratio was calculated using the composition data obtained from1HNMR spectroscopy, applying Kelen-Tudos and Finemann-Ross methods. The reactivity ratio of styrene (r1=0.93) and PDPMA (r2=0.05) suggested random copolymerization...
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The Influence of Water and Mineral Oil on Mechanical Losses in a Hydraulic Motor for Offshore and Marine Applications
PublicationIn this paper, mechanical losses in a hydraulic motor supplied with water and mineral oil (two liquids having significantly different viscosity and lubricating properties) are described and compared. The experimental tests were onducted using a special design (prototype) of a hydraulic satellite motor. The design of the satellite motor is presented. This motor was developed to supply both with water and mineral oil and features...
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Rheological properties, oxidative and thermal stability, and potential application of biopolyols prepared via two-step process from crude glycerol
PublicationIn this work, previously synthesized biopolyols were analyzed in terms of their rheological and thermal properties, very important from the technological point of view. For better evaluation of performed synthesis, the influence of its time and temperature on the properties of biopolyols was determined. In the end, obtained materials were used to prepare rigid polyurethane-polyisocyanurate (PUR-PIR) foams, to evaluate their potential...
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THE INFLUENCE OF WATER AND MINERAL OIL ON MECHANICAL LOSSES IN THE DISPLACEMENT PUMP FOR OFFSHORE AND MARINE APPLICATIONS
PublicationIn this paper mechanical losses in a positive displacement pump supplied with water and mineral oil (two liquids having significantly different viscosity and lubricating properties) are described and compared. The experimental tests were conducted using a special design (prototype) of a satellite pump. The design of the satellite pump is presented in the article. The pump features a non-circular tooth working mechanism. This pump...
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Determination of Mechanical Energy Loss in Steady Flow by Means of Dissipation Power
PublicationWhen systems of simple geometry like pipes or regular channels are considered, the mechan- ical energy loss of the fluid flow can be expressed by local and longitudinal empirical energy loss coefficients. However, in the case of large spatially distributed objects, there are no simple approaches to this task. In practice, general recommendations addressing different types of objects are used, but they usually provide very coarse...
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Zastosowanie audytu wewnętrznego u operatorów produkcyjnych w zapobieganiu kryzysom-studium przypadku
PublicationGłównym tematem artykułu była analiza badań przeprowadzonych u producenta farb proszkowych przedsiębiorstwa X, w zakresie zastosowania audytu wewnętrznego, jako metody pozwalającej na zapobieganie pojawienia się kryzysu. Właściwa współpraca operatorów produkcyjnych z menedżerami ma kluczowe zna-czenie dla budowy właściwej pozycji audytu wewnętrznego w przedsiębiorstwie X. Brak należytej współpracy na etapie badań, przy braku...
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Comparative analysis of coaxial magnetocumulative generators
PublicationThis paper presents the results of a computer simulation of coaxial magnetocumulative current generators (MCGs). The simulation tests were carried out for different values of the internal diameter, length and speed of the deformation of the MGP element.
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Two tests for adhesive bonding long term characterization: principles and applications
PublicationThis article describes recent refinement of the traditional wedge test technique used to characterize durability of the adhesive joints. We propose two types of measuring protocols to monitor precisely and continuously the propagation of an "effective" crack during long term mode I fracture mechanic test. First method is directly derived from the traditional wedge test technique and consist in monitoring the surface strain of adherent...
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The energy approach to fatigue crack growth of S355 steel welded specimens subjected to bending
PublicationThe study presents the results of the research on the rate of fatigue crack growth subjected to bending in the ferritic-pearlitic structure. The studies were carried out at a constant amplitude of the moment and at various values of the load ratios R and at the operating frequency of the machine of 28.4 Hz. Flat specimens made of S355 steel and with fillet welds and with double-sided blunt external notches as well as concave...
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Problems of Active Dynamic Thermography Measurement Standardization in Medicine
PublicationReliability of thermographic diagnostics in medicine is an important practical problem. In the field of static thermography, a great deal of effort has been made to define the conditions for thermographic measurements, which is now the golden standard for such research. In recent years, there are more and more reports on dynamic tests with external stimulation, such as Active Dynamic Thermography, Thermographic Signal Reconstruction...
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Electronic noses in classification and quality control of edible oils: A review
PublicationThe growing demand for wholesome and nutritious food leads to intensification of production, which in turn can have a detrimental effect on quality and well-being of consumers. For that reason, it is important to develop novel methods of food control which would be characterized by a short time of analysis, adequate sensitivity and relatively low cost. One such technique involves the use of multi-sensory devices called electronic...
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Magnetic-field-induced electric quadrupole moments for relativistic hydrogenlike atoms: Application of the Sturmian expansion of the generalized Dirac-Coulomb Green function
PublicationWe consider a Dirac one-electron atom placed in a weak, static, uniform magnetic field. We show that, to the first order in the strength of the external field, the only electric multipole moments, which are induced by the perturbation in the atom, are those of an even order. Using the Sturmian expansion of the generalized Dirac-Coulomb Green function we derive a closed-form expression for the electric quadrupole moment induced...
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THE PROBLEM OF THE BANKING SYSTEM STABILITY IN THE LITERATURE
PublicationThe article is an overview of the literature output in the field of banking sector stability. In the literature a plethora of definitions of the term may be encountered. There is no universal definition of the term. Therefore, the article proposes a unique division of the existing explanations into the following groups: stability determined by the quality of the banking sector, stability in terms of its influence on the macroeconomic...
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IS THE REGIONAL DIVERGENCE A PRICE FOR THE INTERNATIONAL CONVERGENCE? THE CASE OF THE VISEGRAD GROUP
PublicationThe main goal of this article is to verify whether the Visegrad Group countries are achieving social convergence at national level at the expense of internal divergence. For this purpose, the existence of social beta-, sigma- and gamma-convergence at national and regional level was tested. The author of this article decided to tackle the convergence problem since there is a high risk that countries are trying to catch up at...
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The role of resilience in explaining hotel growth: A fuzzy-set QCA approach
PublicationPurpose: Due to the detrimental effects of the recent pandemic on the hotel sector, hotel resilience research and its impact on hotel recovery have received lots of academic attention. However, a sustainable perspective on hotel resilience, as an approach for investigating its impact on long-term hotel growth, has been largely overlooked in the hospitality resilience literature. Therefore, this paper aims to address the research...
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Lighting conditions in home office and occupant’s perception: Exploring drivers of satisfaction
PublicationThis paper depicts lighting home office conditions within different countries and continents, emphasizing the user’s satisfaction with the visual environment. The scope of this article is to investigate the drivers of participants’ satisfaction with the lighting conditions at the home office. The study was developed by a team of international experts working together on Subtask A: User perspective and requirements, Task 61 IEA...
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Employee Well-Being and its Potential Link With Human Knowledge Risks
PublicationEmployee well-being is an essential component of any organisation organisation. Conscious companies make every effort to create a healthy work environment. The well-being of employees and their overall emotional, physical and economic health is affected by various internal and external factors. When employees feel well, they tend to perform better. Therefore, the impact of employee well-being on the organisation is a fact and has...
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Studies of Nonlinear Sound Dynamics in Fluids Based on the Caloric Equation of State
PublicationThe sound speed and parameters of nonlinearity B/A, C/A in a fluid are expressed in terms of coefficients in the Taylor series expansion of an excess internal energy, in powers of excess pressure and density. That allows to conclude about features of the sound propagation in fluids, the internal energy of which is known as a function of pressure and density. The sound speed and parameters of nonlinearity in the mixture consisting...
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Agent System for Managing Distributed Mobile Interactive Documents
PublicationThe MIND architecture of distributed mobile interactive document is a new processing model defined for facilitate informed decision-making in non-algorithmic decision-making processes carried out by knowledge-based organizations. The aim of this architecture is to change the static document to mobile agents, which are designed to implement the structure of the organization through autonomous migration between knowledge workers...
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High-Speed Serial Embedded Deterministic Test for System-on-Chip Designs
PublicationThe paper presents a high-speed serial interface between external tester and Embedded Deterministic Test (EDT) compression logic hosted by SoC designs. With only a single bidirectional link, the system is capable of feeding distributed heterogeneous cores with hundreds of test channels. Moreover, it synergistically supports EDT bandwidth management to improve the overall test performance. A detailed study indicates a high potential...
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Closed-form expression for the magnetic shielding constant of the relativistic hydrogenlike atom in an arbitrary discrete energy eigenstate: Application of the Sturmian expansion of the generalized Dirac–Coulomb Green function
PublicationWe present analytical derivation of the closed-form expression for the dipole magnetic shielding constant of a Dirac one-electron atom being in an arbitrary discrete energy eigenstate. The external magnetic field, by which the atomic state is perturbed, is assumed to be weak, uniform, and time independent. With respect to the atomic nucleus we assume that it is pointlike, spinless, motionless, and of charge Ze. Calculations are...
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On the Nonlinear Effects of Magnetoacoustic Perturbations in Optically Thin Quasi-Isentropic Plasmas
PublicationNonlinear effects of planar magnetosound perturbations in a plasma are discussed. Plasma is non-adiabatic due to optically thin radiation and external heating. For these reasons, thermal instability of a plasma may appear which makes it acoustically active. The plasma is assumed to be initially homogeneous ideal gas with infinite electrical conductivity permeated by a straight magnetic field which is orthogonal to the trajectories...
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Sample preparation and recent trends in volatolomics for diagnosing gastrointestinal diseases
PublicationThe analysis of the human volatilome can be successfully used for rapid and non-invasive diagnostics of gastrointestinal diseases. However, the introduction of techniques based on detection of volatiles is limited, among other factors, by difficulties which arise during the sampling stage and instrumental analysis. The aim of this article was to review and discuss medical and analytical literature on the analysis of volatiles in...
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Bio‐polyols synthesized by liquefaction of cellulose: Influence of liquefaction solvent molecular weight
PublicationCurrently, the plastics industry including polyurethanes is based on the use of petrochemicals. For this reason, scientists are looking for new types of renewable resources for the substitution of petrochemical substances. This work aims to evaluate the effect of polyethylene glycols (PEG) with different molecular mass impact on properties of bio-based polyols synthesized via biomass liquefaction of cellulose. To date, research...
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Topical delivery of pharmaceutical and cosmetic macromolecules using microemulsion systems
PublicationMicroemulsions are transparent, thermodynamically stable colloidal systems. Over the recent years, they have been increasingly investigated due to their potential as skin delivery vehicles for a wide range of drug molecules. The nanoscale particle size and the specificity of microemulsion components are the main features determining the skin permeation process. However, in order to effectively cross the skin barrier, the active...
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Deep Eutectic Solvents or Eutectic Mixtures? Characterization of Tetrabutylammonium Bromide and Nonanoic Acid Mixtures
PublicationDeep eutectic solvents have quickly attracted the attention of researchers because they better meet the requirements of green chemistry and thus have the potential to replace conventional hazardous organic solvents in some areas. To better understand the nature of these mixtures, as well as expand the possibilities of their use in different industries, a detailed examination of their physical properties, such as density, viscosity,...
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Maxillary sinus aeration analysis using computational fluid dynamics
PublicationThe maxillary sinus aeration using the computational fluid dynamics (CFD) method based on individual adult patients’ computed tomography (CT) scans were analyzed. The analysis was based on CT images of 4 patients: one with normal nose anatomy and three with nasal septal deviation (NSD) and concha bullosa (CB). The CFD simulation was performed using the Reynolds-Average Simulation approach and turbulence closure based on linear...
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Processing, Mechanical and Morphological Properties of GTR Modified by SBS Copolymers
PublicationIn this work, ground tire rubber (GTR) was thermo-mechanically treated in the presence of styrene-butadiene-styrene (SBS) copolymers. During preliminary investigation, the effects of different SBS copolymer grades, the variable content of SBS copolymer on the Mooney viscosity, and the thermal and mechanical properties of modified GTR were determined. Subsequently, GTR modified by SBS copolymer and cross-linking agents (sulfur-based...
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The description of non-linear interactions of wave and non-wave modes in a non-adiabatic plasma flow
PublicationThe method of derivation of non-linear equations for interacting modes is explained and applied to a plasma's flow affected by a magnetic field. It is based on the linear projecting of the total perturbation field into specific variations of variables in individual modes of a flow. The method may be applied in many examples of fluid flows with different mechanisms of non-adiabaticity. It is of special importance in complex flows...
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Removal of Siloxanes from Model Biogas by Means of Deep Eutectic Solvents in Absorption Process
PublicationThe paper presents the screening of 20 deep eutectic solvents (DESs) composed of tetrapropylammonium bromide (TPABr) and glycols in various molar ratios, and 6 conventional solvents as absorbents for removal of siloxanes from model biogas stream. The screening was achieved using the conductor-like screening model for real solvents (COSMO-RS) based on the comparison of siloxane solubility in DESs. For the DES which was characterized...
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Interfacial adhesion evaluation in (low-density polyethylene)/elastomer blends
PublicationLow-density polyethylene (LDPE) with different elastomers at a ratio of 50/50 wt% blends was prepared by using a co-rotating twin-screw extruder. Three kinds of elastomers were used: ground tire rubber (GTR), partially crosslinked butyl rubber (KalarVR ), and styrenebutadiene- rubber block copolymer (SBS; KratonVR ). For better characterization of interaction between polyethylene and elastomer, influence of the type of elastomer on...
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Super Dominating Sets in Graphs
PublicationIn this paper some results on the super domination number are obtained. We prove that if T is a tree with at least three vertices, then n2≤γsp(T)≤n−s, where s is the number of support vertices in T and we characterize the extremal trees.
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Exact resultant equilibrium conditions in the non-linear theory of branching and self-intersecting shells
PublicationWe formulate the exact, resultant equilibrium conditions for the non-linear theory of branching and self-intersecting shells. The conditions are derived by performing direct through-the-thickness integration in the global equilibrium conditions of continuum mechanics. At each regular internal and boundary point of the base surface our exact, local equilibrium equations and dynamic boundary conditions are equivalent, as expected,...
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High temperature corrosion of evaporator tubes with thermal sprayed coatings
PublicationDegradation examinations of outer surface of low-emission steam boiler evaporator tubes are presented in the paper. Metallographic evaluation of scale morphology, its micro sites chemical composition analysis and distribution of elements on cross sections have been performed. Water-wall tubes were exposed in steam boiler for up to two years period. Common tubes made of 16Mo3 steel suffered sulphide and molten salts corrosions....