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Wyniki wyszukiwania dla: compression tests
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Combined cold supply system for ship application based on low GWP refrigerants - Thermo-economic and ecological analyses
PublikacjaThe withdrawal of popular high-GWP refrigerants will significantly affect maritime industry. Refrigeration and air conditioning systems currently used on ships are not ready to fulfil future limitations. Therefore, there is a need for system, which will operate with low-GWP refrigerants and at the same time will be efficient and reliable in difficult environmental conditions. This paper explains the concept of a cold supply system,...
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Local dynamics of fluids and dielectrics as the foundation of signal-carrying wave properties
PublikacjaThis paper develops an original approach to fundamental problems of classical linear acoustics and electromagnetics, proving a crucial role of doubly-dynamic local properties of a propagation medium in supporting wave-like fields able to carry information signals. The proof is composed of two steps concerning, subsequently, fluid acoustics and dielectric electromagnetics. The first step consists in complementing a common, practically...
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Analyses of Shear Angle in Orthogonal Cutting of Pine Wood
PublikacjaThe determination of energy effects for wood machining processes, such as cutting power and cutting forces, is very useful in designing of manufacture process of wooden products. A more accurate prediction of cutting forces requires a correct determination of the shear angle value, which can be determined using various models. In this article, shear angle values for an orthogonal linear cutting process of pine wood are determined. The...
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Computations of critical load value of composite shell with random geometric imperfections
PublikacjaThe work presents the numerical analysis of composite shell with geometric imperfections subjected to compression along its generatrix. The imperfections are described as single indentations and random fields with random parameters of shape and correlation. The fields are generated with the use of the authors made program. Using the authors’ FEM software as well as commercial package Femap with NX Nastran, the critical load values...
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LEGAL ASPECTS OF ELECTRIC ENERGY GENERATION IN A FLOATING POWER PLANT
PublikacjaThis paper discusses the characteristics of pollution and legal regulations governing investment projects affecting the environment. It describes a combined system of a compression ignition engine and a steam turbine, whose aim, when placed on a floating platform, is to produce electric energy in a so-called distributed generation system. Such a system involves a reciprocating internal combustion engine and a connected steam turbine...
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Evaluation of compression realization in diesel engine based on performance indicator changes
PublikacjaIn the article a method of evaluation of a diesel engine during the realization of processes of working cycle on the example of compression is described. The method is based on the use of the quantity called performance indicator in the description of the engine's work, which contains the information on the energy values, which may be disposed using the engine and the time at which it can be delivered. Theoretical information has...
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The forming and emission of high power electromagnetic pulses
PublikacjaAn impulse energy source, a power conditioning system and an electromagnetic field emitter are essential to generate an electromagnetic field pulse (EMFP) with a specific frequency bandwidth. Selected simulation results for a power conditioning system consisting of a fuse opening switch and a paraboloidal electromagnetic emitter have been presented in this article. The synthetic system examined in the simulation is powered by an...
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The Dominant Influence of Plastic Deformation Induced Residual Stress on the Barkhausen Effect Signal in Martensitic Steels
PublikacjaThe paper presents the results of investigation of the influence of plastic deformation on the magnetic properties of martensitic steel (P91 grade). The properties of the hysteresis loops as well as of the Barkhausen effect (BE) signal are analysed for both tensile and compressive loading up to ε = 10% of plastic deformation. The choice of the steel and of the deformation range is unique, since for such combination one can expect...
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The forming and emission of high power electromagnetic pulses
PublikacjaAn impulse energy source, a power conditioning system and an electromagnetic field emitter are essential to generate an electromagnetic field pulse (EMFP) with a specific frequency bandwidth. Selected simulation results for a power conditioning system consisting of a fuse opening switch and a paraboloidal electromagnetic emitter have been presented in this article. The synthetic system examined in the simulation is powered by...
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Wireless intelligent audio-video surveillance prototyping system
PublikacjaThe presented system is based on the Virtex6 FPGA and several supporting devices like a fast DDR3 memory, small HD camera, microphone with A/D converter, WiFi radio communication module, etc. The system is controlled by the Linux operating system. The Linux drivers for devices implemented in the system have been prepared. The system has been successfully verified in a H.264 compression accelerator prototype in which the most demanding...
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Rigid polyurethane foams modified with selected flame retardants
PublikacjaThe flame retardants: expandable graphite, triethylphosphatehas been used in rigid polyurethane foams (PUFs). The influence of fillers amounts on processing parameters, physical-mechanical properties (compression strength, density, water absorption, brittleness)and thermal properties (thermal stability) of such foams has been analyzed.The gel, cram and rise time for PUFs modified with flame retardant has been observed during synthesis...
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Solvation phenomena in ternary system tetramethylurea-methylacetamide-water: Insights from volumetric, compressibility and FTIR analysis
PublikacjaThe properties of the ternary systems N,N,N’,N’-tetramethylurea - N-methylacetamide - water were investigated using Fourier-transform infrared spectroscopy (FTIR), volumetric and compression measurements. Densities and sound velocities were determined in order to obtain the apparent molar volumes (VΦ) and apparent molar isentropic compressions (ΚS,Φ). These values were then extrapolated to infinite dilution. Additionally, interaction parameters...
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Smaller Representation of Finite State Automata
PublikacjaThis paper is a follow-up to Jan Daciuk's experiments on space-effcient finite state automata representation that can be used directly for traversals in main memory. We investigate several techniques of reducing memory footprint of minimal automata, mainly exploiting the fact that transition labels and transition pointer offset values are not evenly distributed and so are suitable for compression. We achieve a gain of around 20-30%...
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Preparation, morphology and properties of natural rubber composites filled with untreated short jute fibres
PublikacjaGreen composites were obtained by incorporation of short jute fibres in natural rubber matrix using a laboratory two-roll mill. The influence of untreated fibre content (1, 2.5, 5, 7.5 and 10 phr) on the mechanical properties, dynamic mechanical properties, swelling properties was examined. The behaviour of prepared green composites under cyclic compression was also investigated. Fibre dispersion in rubber matrix was studied by...
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A procedure for elastoplastic hardening function identification.
PublikacjaThe inverse analysis method for identifying a nonlinear hardening function,which governs a plastic yielding of soil and rock materials in the framework of elastoplastic theory is presented. A concept of two stage finite element based on spatial discretization of computational space and hardening function space is introduced. The proposed inverse analysis can be classified as the output least squares method. The Levenberg Marquard...
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Smaller representation of finite state automata
PublikacjaThis paper is a follow-up to Jan Daciuk's experiments on space-efficient finite state automata representation that can be used directly for traversals in main memory (Daciuk, 2000)[4]. We investigate several techniques for reducing memory footprint of minimal automata, mainly exploiting the fact that transition labels and transition pointer offset values are not evenly distributed and so are suitable for compression. We achieve...
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Thermodynamic analysis of the Compressed Air Energy Storage system coupled with the Underground Thermal Energy Storage
PublikacjaImprovement of flexibility is one of the key challenges for the transformation of the Polish Power System aiming at a high share of renewable energy in electricity generation. Flexible and dispatchable power plants will contribute to this ongoing transformation process as they compensate for fluctuations in electricity generation from renewable energy sources such as wind and photovoltaics. In this context, CAES storage tanks are...
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Robust and Efficient Machine Learning Algorithms for Visual Recognition
PublikacjaIn visual recognition, the task is to identify and localize all objects of interest in the input image. With the ubiquitous presence of visual data in modern days, the role of object recognition algorithms is becoming more significant than ever and ranges from autonomous driving to computer-aided diagnosis in medicine. Current models for visual recognition are dominated by models based on Convolutional Neural Networks (CNNs), which...
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Te use of acoustic emission for assessment of the oil lubricity in a four-ball tester
Publikacjain view of the increased dynamic and temperature load in the compression-ignition engine tribological systems, particular attention is drawn to the problem of such lubrication of the friction nodes that after breaking the boundary layer it could be restored without any wear occurring. therefore, an idea has been devised of introducing to friction nodes, with the lubrication oils, of new substances (operational preparations) modifying...
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rigid polyurethane foams modified with selected nanofillers
PublikacjaThe nanofillers: natural montmoryllonite (MMT) - Bentonite, natural MMT modified with a quaternary ammonium salt - Cloisite30B, has been used in rigid polyurethane foams (PUFs). The influence of fillers amounts on processing parameters, physical-mechanical properties (density, water absorption, brittleness and compression strength) and thermal properties (thermal stability, fire behaviours) of such foams has been analysed. The...
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Stability and limit load analysis of a cold-formed channel section column
PublikacjaThe paper presents stability and limit load analysis of a steel column 1440 mm high of a cold-formed channel section, subjected to a combination of compression and bending. Experimental results were compared to the resistance of a code procedure and to the outcome of numerical non-linear analysis. Comparison was made of numerical solutions by means of static (Riks) and dynamic (Explicit and Implicit) methods. Perfectly elastic...
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Average Size of a Suffix Tree for Markov Sources
PublikacjaWe study a suffix tree built from a sequence generated by a Markovian source. Such sources are more realistic probabilistic models for text generation, data compression, molecular applications, and so forth. We prove that the average size of such a suffix tree is asymptotically equivalent to the average size of a trie built over n independentsequences from the same Markovian source. This equivalenceis only known for memoryless...
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Continuum models for pantographic blocks with second gradient energies which are incomplete
PublikacjaWe postulate a deformation energy for describing the mechanical behavior of so called pantographic blocks, that is bodies constituted by stacking of layers of pantographic sheets. We remark that the pantographic effect is limited in the plane of pantographic sheets and therefore only the second derivatives of transverse displacements along the pantographic fibers appear in the chosen deformation energy. We use this novel energy...
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Analysis of impact of audio modifications on the robustness of watermark for non-blind architecture
PublikacjaThe aim of this paper is to assess the robustness of the non-blind audio content watermarking scheme proposed by the authors. The authors present the architecture of the designed system along with the employed workflows for embedding and extracting the watermark followed by the implementation phase description and the analysis of the experimental results. Some possible attack simulations on the embedded watermarks are reviewed,...
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Time variable gain for long range sonar with chirp sounding signal
PublikacjaThe main purpose of applaying Time Variable Gain (TVG) in active sonars with digital signal processing is to reduce dynamic range of echo signal and adapt it to the dynamic range of the analogue to digital conversion. With high transmission losses level, the dynamic range of the input signal in long range sonars can be very high and even exceed 200dB. When chirp sounding signals with matched filtration are used, sonars can raech...
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Analysis of impact of lossy audio compression on the robustness of watermark embedded in the DWT domain for non-blind copyright protection
PublikacjaA methodology of non-blind watermarking of the audio content is proposed. The outline of audio copyright problem and motivation for practical applications are discussed. The algorithmic theory pertaining watermarking techniques is briefly introduced. The system architecture together with employed workflows for embedding and extracting the watermarks are described. The implemented approach is described and obtained results are reported....
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Microstructure, mechanical properties, and flame retardancy of nanoclay-incorporated polyurethane flexible foam composites
PublikacjaThe present work seeks to investigate microstructure, mechanical properties, and flame retardancy of polyurethane/nanoclay flexible foam composites. In this regard, we prepared various nanocomposites with and without nanoclay and observed the resulting morphologies to correlate them with the other corresponding characteristics. The results provided support for the fact that tensile strength and compression set will increase with...
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Processing of Polyester-Urethane Filament and Characterization of FFF 3D Printed Elastic Porous Structures with Potential in Cancellous Bone Tissue Engineering
PublikacjaThis paper addresses the potential of self-made polyester-urethane filament as a candidate for Fused Filament Fabrication (FFF)-based 3D printing (3DP) in medical applications. Since the industry does not provide many ready-made solutions of medical-grade polyurethane filaments, we undertook research aimed at presenting the process of thermoplastic polyurethane (TPU) filament formation, detailed characteristics, and 3DP of specially...
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Orientation effects on the fracture behaviour of additively manufactured stainless steel 316L subjected to high cyclic fatigue
PublikacjaIn this paper, stainless steel 316L (SS316L) bars were additively manufactured (AM) in three orientations (Z – vertical, XY – horizontal, ZX45 – midway between vertical and horizontal) by using the Laser Powder Bed Fusion Melting (LPBF-M) method. The AM specimens were subjected to load control fatigue testing under full tension and compression (R = -1) at stress amplitudes ±350, ±400 and ±450 MPa. The XY and ZX45 printing orientations...
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Local buckling of compressed flange of cold-formed channel members made of aluminum alloy
PublikacjaThe paper deals with local buckling of a compressed single flange of thin-walled channel cold- formed columns and beams made of aluminum alloy. Material is described by means of the Ramberg-Osgood constitutive equation. Axial compression of the columns and beams undergoing bending is taken into consid- eration. A simple model of the member flange in the form a long beam elastically connected to the web is used to find the critical...
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High-Speed Serial Embedded Deterministic Test for System-on-Chip Designs
PublikacjaThe 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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The hydration of the protein stabilizing agents: trimethylamine-N-oxide, glycine and its N-methylderivatives - the volumetric and compressibility studies
PublikacjaThe densities at T = (288.15, 293.15, 298.15, 303.15, and 308.15) K and sound velocities at T = 298.15 K have been measured for aqueous solutions of trimethylamine-N-oxide, glycine, N-methylglycine (sarcosine), N,N-dimethylglycine, N,N,N-trimethylglycine (betaine). From these data the apparent molar volumes, VΦ, the apparent molar isentropic compressions, KS,Φ, and the solvation numbers of solutes have been determined. The concentration...
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Experiments on compression ignition engine powered by nano-fuels
PublikacjaThe use of nanoparticles in fuels provides new opportunities for modification of fuel properties, which may affect the operational parameters of engines, in particular the efficiency and fuel consumption. The paper presents comparison of compression ignition engine performance fuelled with neat diesel and nano-diesel. Alumina (Al2O3) was used as nanoparticles. Surface-active substances, including Span 80 surfactant, as well as...
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Highly sensitive large strain cellulose/multiwalled carbon nanotubes (MWCNTs)/thermoplastic polyurethane (TPU) nanocomposite foams: From design to performance evaluation
PublikacjaAerogel-based polymer composite foams are promising for large strain piezoresistive sensors, but their aerogel skeleton is partially destroyed during the foaming process, limiting their sensitivity. Herein, the thermoplastic polyurethane was synthesized on the aerogel skeleton to obtain cellulose/multiwalled carbon nanotubes (MWCNTs)/thermoplastic polyurethane (TPU) nanocomposite materials foamed with the aid of supercritical carbon...
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Application of the near-infrared spectroscopy in the pharmaceutical technology
PublikacjaNear-infrared (NIR) spectroscopy is currently the fastest-growing and the most versatile analytical method not only in the pharmaceutical sciences but also in the industry. This review focuses on recent NIR applications in the pharmaceutical technology. This article covers monitoring, by NIR, of many manufacturing processes, such as granulation, mixing or drying, in order to determine the end-point of these processes. In this...
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ISSUES OF ECONOMIC ANALYSIS OF ELECTRIC ENERGY GENERATION IN A FLOATING POWER PLANT
PublikacjaThis article presents basic dependences for conducting a technical and economic analysis related with investment projects. It describes a combined system of a compression ignition engine and a steam turbine, whose aim, when placed on a floating platform, is to generate electric energy in the so-called distributed generation system. Such a system involves a reciprocating internal combustion engine and a connected steam turbine system...
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Performance of isotropic constitutive laws in simulating failure mechanisms in scaled RC beams
PublikacjaResults of numerical calculations of reinforced concrete (RC) beams are presented. Based on experimental results on longitudinally reinforced specimens of different sizes and shapes are investigated. Four different continuum constitutive laws with isotropic softening are used: one defined within continuum damage mechanics, an elasto-plastic with the Rankine criterion in tension and the Drucker-Prager criterion in compression, a...
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Three-Dimensional Printing of Bone Models
PublikacjaThe trabecular bone occurs, for example, in the femoral heads. Understanding the phenomenon of bone tissue degeneration can be the basis for the possibility of looking for alternative methods of surgical treatment of bone loss. The paper presents the results of the trabecular bone model, which was produced in additive manufacturing method with fused filament fabrication technology. The verification of the mechanical behavior of...
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Buckling Analysis of a Micro Composite Plate with Nano Coating Based on the Modified Couple Stress Theory
PublikacjaThe present study investigates the buckling of a thick sandwich plate under the biaxial non-uniform compression using the modified couple stress theory with various boundary conditions. For this purpose, the top and bottom faces are orthotropic graphene sheets and for the central core the isotropic soft materials are investigated. The simplified first order shear deformation theory (S-FSDT) is employed and the governing differential...
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Morphology and the physical and thermal properties of thermoplastic polyurethane reinforced with thermally reduced graphene oxide
PublikacjaIn this study, thermally reduced graphene oxide (TRG)-containing polyurethane nanocomposites were obtained by the extrusion method. The content of TRG incorporated into polyurethane elastomer systems equaled 0.5, 1.0, 2.0 and 3.0 wt%. The morphology, static and dynamic mechanical properties, and thermal stability of the modified materials were investigated. The application of TRG resulted in a visible increase in material stiffness...
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Application analysis of a hybrid solid oxide fuel cell-gas turbine system for marine power plants
PublikacjaThe results of theoretical studies of the possibilities of using hybrid solid oxide fuel cell–gas turbine (SOFC-GT) systems for marine power plants are presented. A 500 kW auxiliary marine power plant scheme using stacks of SOFCs in combination with a regenerative gas turbine operating with over-expansion based on our recent patent application is proposed. The results of mathematical modelling showed the opportunity to obtain a...
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Bioactive core material for porous load-bearing implants
PublikacjaSo far state of knowledge on biodegradable materials is reviewed. Among a variety of investigated materials, those composed of polymers and ceramics may be considered as only candidates for a core material in porous titanium alloy. The collagen and chitosan among natural polymers, polyhydroxy acids among synthetic polymers, and hydroxyapatite and tricalcium phosphate among ceramics are proposed for further research. Three essential...
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THE INTERACTION BETWEEN STEEL COLUMN CHORD AND CLOSELY SPACED REINFORCEMENT.
PublikacjaNowadays, more often than before, civil engineering designers are willing to use steel build-up members composed of single or doubled cold-formed chords interconnected using different mechanical connectors. This paper subject is an analysis of cooperation of a closely spaced built-up cold-formed chord interconnected with series of bolts that are located along the length of the member in a specific spacing. This distance along the...
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Joint fingerprinting and decryption method for color images based on quaternion rotation with cipher quaternion chaining
PublikacjaThis paper addresses the problem of unauthorized redistribution of multimedia content by malicious users (pirates). In this method three color channels of the image are considered a 3D space and each component of the image is represented as a point in this 3D space. The distribution side uses a symmetric cipher to encrypt perceptually essential components of the image with the encryption key and then sends the encrypted data via...
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Investigations on strength and fracture in RC beams scaled along height or length
PublikacjaThe objective of the present paper is to identify experimentally and theoretically differing failure mechanisms in reinforced concrete beams subjected to four-point bending for a separate variation of the depth and length at the constant thickness. Experiments were performed on reinforced concrete beams under four-point bending. Different failure mechanisms included steel yielding, diagonal tension or shear- compression depending...
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Influence of Properties of Hydraulic Fluid on Pressure Peaks in Axial Piston Pumps’ Chambers
PublikacjaThe article concentrates on the research of the pressure peaks in a working chamber of an axial piston pump. The main focus of the article is the influence of fluid properties on the pressure peaks value. Experimental and analytical methods were used to determine the impact of the fluid density, viscosity, compressibility and aeration. The article describes the pressure peak generation process and explains the theoretical basis...
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Current divider-based nanosecond high current pulse measuring systems
PublikacjaThis paper presents the analysis of the new approach to the measurement methodology of significant values (in order of hundreds of kA) and huge steepness (in order of MA/μs) current pulses based on current dividers along with a comparison of the various types transducers suitability in measuring systems with such extreme parameters. Such dividers are used to extend the measurement ranges of current transducers with limited current...
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Direct reduction of pellets through hydrogen: Experimental and model behaviour
PublikacjaThis paper presents the hydrogen reduction behaviour of industrial pellets designed for the efficient hydrogen based direct reduction. The pellets were provided with very low non ferrous oxides percentage (0.52 of basicity index) and with the absence on TiO2 oxides. The pellets measured diameters in the range 1.14–1.72 cm and were characterized in terms of porosity, pores size, tortuosity and compression strength. The pellets were...
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On Symmetry of Uniform and Preferential Attachment Graphs
PublikacjaMotivated by the problem of graph structure compression under realistic source models, we study the symmetry behavior of preferential and uniform attachment graphs. These are two dynamic models of network growth in which new nodes attach to a constant number m of existing ones according to some attachment scheme. We prove symmetry results for m=1 and 2 , and we conjecture that for m≥3 , both models yield asymmetry with high...
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Innovative cold-formed GEB section under compression
PublikacjaCold-formed steel sections extensively affect the modern steel construction industry. Not only are they used as secondary elements like purlins or sheeting, but also they can serve as primary load-bearing members in fabricated steel panels and trusses. A new cross-section called shortly a GEB may serve as that member. However, its existence of the metal building structures industry depends on the exact, optimal dimensional parameters...