bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Influence of the Shape of Turbulence Inhibitors on the Hydrodynamic Conditions Occuring in a Tundish
Authors: Merder T. 
Published: January 2014

Abstract
The article presents results of the research that was carried out taking into account the influence of the (impact pads) turbulence inhibitor geometry and its equipment of the working space on the hydrodynamic conditions occurring in T-type tundish. Four different turbulence inhibitors were discussed. They differ in shape and configuration of external walls. The research was conducted basing on the numerical simulations as well as on tests performed on physical water model. As a result of calculations the velocity field distribution, turbulence field and marker concentration distribution in the liquid steel for the tested geometrical variants of turbulence inhibitors were obtained. Worked out RTD curves (Residence Time Distribution) allowed to determine the kinetics of steel mixing (the range of transient zone was estimated), and the percentage participation of the particular flow zones. The test carried out on the water model concerned one of the tested turbulence inhibitors. Research was done to verify the parameter settings of the numerical model applied in calculations. Obtained results gave valuable information about the work of the object after applying different turbulence inhibitors.
Investigation of the Usability of Cubic Boron Nitride Cutting Tools as an Alternative to Diamond Cutting Tools for the Aircraft Industry
Authors: Islak S. , Kir D. , Çelik H. 
Published: January 2014

Abstract
Diamond and cubic boron nitride (cBN) cutting segments were produced using hot pressing technique for this study to be used in cutting natural stone. cBN grains were added to bronze powder, the chosen matrix, at a rate of 0%, 20%, 40%, 60%, 80%, and 100% (according to percentage by weight). Segments were produced under a pressure of 35 MPa, at a sintering temperature of 600°C, over a sintering time of 3 minutes. The cutting properties of the produced segments were determined by cutting Ankara andesite. A Scanning Electron Microscope (SEM) and an X-Ray Diffractometer (XRD) were used to analyse the microstructure, phase compound, and wear surfaces of each segment type.
Thermo-Mechanical Model of a TIG Welding Process for the Aircraft Industry
Authors: Hojny M. 
Published: January 2014

Abstract
TIG welding is the most important process, which is used in the aircraft industry. A number of components of airplane are made using this method. Thermo-mechanical models are needed to understand better phenomena involved in this process. In the presented work thermo-mechanical simulations were performed and the possibilities of welding distortion in the investigated process were evaluated. Comparison of the results of numerical simulation with the experimental data confirmed good predictive capabilities of the model and quite good description of the phenomena involved in this process.
Premature Cracking of Dies for Aluminium Alloy Die-Casting
Authors: Pawłowski B. , Bala P. , Tokarski T. , Krawczyk J. 
Published: January 2014

Abstract
Two identical dies for aluminium alloy die-casting failed prematurely because of a number of parallel cracks on the working surface. These cracks were of a mechanical nature related to incorrect microstructural banding orientation of the die core and related to improper heat treatment. The microstructural banding orientation was determined by metallographic examination of the specimens, which were cut from the dies along the three axes of the coordinate system. Scanning electron microscopy (SEM) examination of the fracture surfaces and along the crack path (including energy dispersive spectroscopy (EDS) analysis) indicated that the root cause of the premature cracking of the dies was improper heat treatment (quenching and tempering conditions). Additionally, resistance to fracture of the investigated specimens, as measured by the Charpy V-notch test, was five times lower than that required for the desired hardness.
Microstructure and Corrosion Resistance Characteristics of Cr-Co-Mo Alloys Designed for Prosthetic Materials
Authors: Augustyn-Pieniążek J. , Lukaszczyk A. , Zapala R. 
Published: January 2014

Abstract
The work presents the results of microscopic tests of two alloys: Co-Cr-Mo and Co-Cr-W-Mo, together with a quantitative local analysis of the chemical composition, with the use of an electron microprobe X-ray analyzer EDS. Corrosion resistance tests were also performed on the alloys, in the artificial saliva environment. The microstructure of the examined alloys was of the dendrite type. An eutectic consisting of alloy carbides and a cobalt austenite was observed in the interdendritic spaces. The dendritic matrix was a solid solution of chromium, molybdenum and carbon in cobalt (Co), and the precipitates present in the interdendritic spaces were rich with Cr and Mo - in the case of Co-Cr-Mo - and with W and Mo - in the case of Co-Cr-W-Mo. The analyzed materials exhibited a similar progress of polarization curves. The obtained currentless potential values and the wide passivation area of those alloys made it possible to conclude their high corrosion resistance in the examined environment.
Studies on Stress and Strain State in Cold Orbital Forging a AlMgSi Alloy Flange Pin
Authors: Samołyk G. 
Published: January 2014

Abstract
The orbital forging is one of the metal forming processes which enables the manufacture of products through worm or cold working. A characteristic feature of this technological process is the use of a special wobbling motion of one of the tools in order to reduce the required forming force. This is particularly advantageous during the formation of products in the shape of a disc or a flange pin. Unfortunately, typical constraints of cold orbital forging are: uncontrolled buckling, loss of shape stability (“mushroom effect”) and cracks. They depend on the technological parameters of the process and their cause can be explained on the basis of e.g. workpiece stress state analysis, which is a difficult task due to the complexity of orbital forging process. The article discusses the issues of stress and strain in cold orbital forged parts of the flange pin type, made of AlMgSi aluminum alloy. The results of the presented FEM simulation, verified experimentally, explain the influence of the theoretical aspects of this process on its implementation conditions. It is assumed that orbital forging is performed on the PXW-100A press and the numerical model takes into account all possible variants of the process. Debate boils down to discussing the stress and strain state (e.g. analyzing the stress and strain rate fields) occurring in the workpiece in the context of chosen technological parameters and constrains of orbital forging process
On the Reconstruction Method of Ceramic Foam Structures and the Methodology of Young Modulus Determination
Authors: Nowak M. , Nowak Z. , Pęcherski R.B. , Potoczek M. , Śliwa R.E. 
Published: January 2014

Abstract
In the present paper a finite element model was used to investigate the mechanical properties such as Young’s modulus of open-cell ceramic foam. Finite element discretization was derived from real foam specimen by computer tomography images. The generated 3D geometry of the ceramic foam was used to simulate deformation process under compression. The own numerical procedure was developed to control finite element mesh density by changing the element size. Several numerical simulations of compression test have been carried out using commercial finite element code ABAQUS. The size of the ceramic specimen and the density of finite element mesh were examined. The influence of type and size of finite element on the value of Young’s modulus was studied, as well. The obtained numerical results have been compared with the results of experimental investigations carried out by Ortega [11]. It is shown that numerical results are in close agreement with experiment. It appears also that the dependency of Young’s modulus of ceramic foam on density of finite element mesh cannot be ignored.
Mathematical Foundations of Limit Criterion for Anisotropic Materials
Authors: Ostrovvska-Maciejewska J. , Szeptyński P. , Pęcherski R.B. 
Published: January 2014

Abstract
In the paper a new proposition of limit state criteria for anisotropic solids exhibiting different strengths at tension and compression is presented. The proposition is based on the concept of energetically orthogonal decompositions of stress state introduced by Rychlewski. The concept of stress state dependent parameters describing the influence of certain stress modes on the total measure of material effort was firstly presented by Burzynski. The both concepts are reviewed in the paper. General formulation of a new limit criterion as well as its specification for certain elastic symmetries is given. It is compared with some of the other known limit criteria for anisotropic solids. General methodology of acquiring necessary data for the criterion specification is presented. The ideas of energetic and limit state orthogonality are discussed - their application in representation of the quadratic forms of energy and limit state criterion as a sum of square terms is shown
Fabrication of Ceramic Aggregate from Phosphogypsum and Power Plant Ash – Preliminary Studies
Authors: Sokołowski J. , Urbańska P. 
Published: January 2014

Abstract
The compositions of phosphogypsum and power plant ash as waste created in the production of an orthophosphoric acid and the coal combustion with the addition of fine coal were prepared. The compositions were then granulated and sintered in a muffle furnace in the atmosphere of air under the conditions previously determined. The compressive strength, open porosity and water absorption were also determined and compared with the results obtained for the commercial aggregate. Chemical and phase compositions of the aggregate were also studied. The results of the research indicate that proposed method of the high temperature utilization of phosphogypsum and power plant ash has a great potential for application and it is worth of further research.
Technology and Properties PMN-PT-PS-PFN:LI Material for Multilayer Capacitor
Authors: Niemiec P. , Skulski R. , Bochenek D. , Wawrzała P. 
Published: January 2014

Abstract
In this work it is designed and obtained the multicomponent material with the formula 0.6075PMN-0.2025PT-0.09PS- 0.1PFN:Li (PMN-PT-PS-PFN:Li) for applications in multilayer ceramic capacitors MLCC. Obtaining of PMN-PT-PS-PFN:Li was done by two alternative methods of synthesis. In the first method a PMN-PT-PS-PFN:Li has been obtained from simple compounds (oxides, carbonates), in the second method the complex compounds (MgNb2O6 and FeNbO4) and simple compounds (oxides PbO, TiO2 and carbonate Li2CO3) were used. From synthesized powder of PMN-PT-PS-PFN:Li the ceramic samples were obtained which have next undergone comprehensive investigations. The X-ray investigations, as well as ferroelectric, dielectric and elastic investigations have been made.
Application of Ceramic Preforms to the Manufacturing of Ceramic - Metal Composites
Authors: Jach K. , Pietrzak K. , Wajler A. , Sidorowicz A. , Brykała U. 
Published: January 2014

Abstract
This paper presents new solution to manufacturing Cu-Al2O3 composites with a dispersed reinforcement phase. It consists in substituting commonly used commercial alumina powder with crushed ceramic foam. Very low strength of thin-walled Al2O3 porous foams results in both their easy destruction and isolation of fragments <200 μm. The addition of the ceramic phase is 3-10 vol.%. The sintering process is performed for 30 min in a hot-press at 1050°C and 30 MPa. The aim of the presented paper is to study the effect of the volume content of the ceramic phase on the microstructure and selected physical and thermal properties of copper - alumina composites.
MINING-INDUCED SURFACE HORIZONTAL DISPLACEMENT: THE CASE OF BW PROSPER HANIEL MINE / ANALIZA PRZEMIESZCZEŃ POZIOMYCH POWIERZCHNI TERENU WYWOŁANYCH PODZIEMNĄ EKSPLOATACJĄ GÓRNICZĄ NA PRZYKŁADZIE KOPALNI BW PROSPER HANIEL
Authors: Tajduś Krzysztof 
Published: January 2014

Abstract
The paper presents a wide-ranged analysis of horizontal displacements in the region of underground mining exploitation. Initially, various theories pertaining to the determination of mining-induced horizontal displacement are discussed, followed by a complex study on horizontal displacements measured for a selected example region of the German coal mine BW Prosper Haniel, as well as the determination of displacement factor B.
UNIQUE PROJECT OF SINGLE-CUTTING HEAD LONGWALL SHEARER USED FOR THIN COAL SEAMS EXPLOITATION / PROJEKT JEDNOORGANOWEGO KOMBAJNU ŚCIANOWEGO O SPECJALNEJ KONSTRUKCJI PRZEZNACZONEGO DO EKSPLOATACJI POKŁADÓW CIENKICH
Authors: Bołoz Łukasz 
Published: January 2014

Abstract
Problem of thin hard coal seams exploitation, including chosen data related with their resources in Poland, has been discussed in the introduction of the present study. On the basis of actually operated machines the assumptions, which should be satisfied by the longwall shearer used for exploitation of thin hard coal seams, have been made. A project of such longwall shearer combined with band conveyor and mechanized longwall support, including description of the machine operation technology and analysis of possible day output achievement, have been presented.
RESULTS OF THE PROMETHEE METHOD APPLICATION IN SELECTING THE TECHNOLOGICAL SYSTEM AT THE MAJDAN III OPEN PIT MINE / WYNIKI ZASTOSOWANIA METODY PROMETHEE DO WYBORU SYSTEMU TECHNOLOGICZNEGO W KOPALNI ODKRYWKOWEJ MAJDAN III
Authors: Vujić Slobodan , Hudej Marjan , Miljanović Igor 
Published: January 2014

Abstract
This paper discusses the application of the PROMETHEE model and the results achieved in practice, following the example of the multi-criteria selection of the technological system at the Majdan III clay mineral raw material open pit mine of the Potisje Company, Republic of Serbia. After the introduction comments, reasons are explained for selecting the new technological system, conditions and limitations for the seven alternative solutions considered are described, mathematical foundation for the PROMETHEE method and a multi-criteria model of the problem in question are presented. The solution with the following structure was ranked first and accepted by the Company management as the best: Bucket chain excavator - Conveyor belts - Spreader (ECS), alongside a decision is made on the acquisition of machinery and system construction. The system was put into operation in 2000. The experience and the data accumulated in the previous twelve years confirm that the decision made on the application of the ECS technology was just, and the conclusion lists the benefits achieved.
VERIFICATION OF FLOTATION KINETICS MODEL FOR TRIANGULAR DISTRIBUTION OF DENSITY FUNCTION OF FLOTABILITY OF COAL PARTICLES / WERYFIKACJA MODELU KINETYKI FLOTACJI DLA TRÓJKĄTNEGO ROZKŁADU FUNKCJI GĘSTOŚCI FLOTOWALNOŚCI ZIAREN WĘGLA
Authors: Kalinowski Krystian , Kaula Roman 
Published: January 2014

Abstract
Parameters of flotation kinetics model with a gamma and a triangular distribution have been determined based on the batch coal flotation experiments. Analyses were carried out at different values of the intensity of aeration air. The results of example analyses are presented in tables and graphs form. It follows from the carried out study on the mathematical models of flotability coefficient distribution of particles of examined coal samples that the triangular distribution model is statistical equivalent to the gamma flotability distribution. The assumption of the triangular distribution enables determination of the density function of distribution of fraction in the industrial flotation machines. Knowledge of this function will allow better evaluation of the phenomena occurring in the process of enrichment. It may be one of the basic information used in the supervisory control system.
THE EFFECT OF TEMPERATURE GLIDE OF R407C REFRIGERANT ON THE POWER OF EVAPORATOR IN AIR REFRIGERATORS / WPŁYW POŚLIZGU TEMPERATURY CZYNNIKA CHŁODNICZEGO R407C NA MOC PAROWNIKA CHŁODZIARKI POWIETRZA
Authors: Nowak Bernard , Życzkowski Piotr 
Published: January 2014

Abstract
The article discusses the effect of the phenomenon of temperature glide of zeotropic refrigerants on thermal power of an evaporator in an air compression refrigerator. Zeotropic mixtures are subject to phase transitions, the process of which significantly differs from that of homogeneous refrigerants. In contrast to homogeneous refrigerants, where boiling and condensing processes take place at a constant temperature, for the zeotropic mixtures it is essential to know the vapor quality to unambiguously determine the temperature at which the evaporation process is initiated. The R407C refrigerant serves as an example to describe the method of determining the initial temperature of the evaporation process taking into account the effect of temperature glide. The developed formula (7) has been based on a proven linear course of isobars in the two-phase region (Fig. 5) and thus determining a polynomial describing their angle of inclination (8). In addition, temperature calculation formulas (9) and specific enthalpy (10) of dry saturated vapor of the R407C refrigerant have been presented as well. This approach allows to determine the temperature of the R407C refrigerant at the inlet to the evaporator without the required knowledge of its vapor quality. The previously used simplified methods for determining the temperature of a refrigerant at the inlet to the evaporator result in considerable deviations in calculated power of the evaporator compared with its actual value. The presented calculation example involving mine air compression refrigerator of TS-450P type shows that relative deviations of the evaporator thermal power may even exceed 20%. This example compares two simplified methods for determining zeotropic evaporating temperature of a refrigerant used in comparative calculations of refrigerants with the method presented in this article.
Mathematical model of a plate fin heat exchanger operating under solid oxide fuel cell working conditions
Authors: Kupecki Jakub , Badyda Krzysztof 
Published: January 2014

Abstract
Heat exchangers of different types find application in power systems based on solid oxide fuel cells (SOFC). Compact plate fin heat exchangers are typically found to perfectly fit systems with power output under 5 kWel. Micro-combined heat and power (micro-CHP) units with solid oxide fuel cells can exhibit high electrical and overall efficiencies, exceeding 85%, respectively. These values can be achieved only when high thermal integration of a system is assured. Selection and sizing of heat exchangers play a crucial role and should be done with caution. Moreover, performance of heat exchangers under variable operating conditions can strongly influence efficiency of the complete system. For that reason, it becomes important to develop high fidelity mathematical models allowing evaluation of heat exchangers under modified operating conditions, in high temperature regimes. Prediction of pressure and temperatures drops at the exit of cold and hot sides are important for system-level studies. Paper presents dedicated mathematical model used for evaluation of a plate fin heat exchanger, operating as a part of micro-CHP unit with solid oxide fuel cells.
Numerical analysis of CO2 capture efficiency in post combustion CCS technology in terms of varying flow conditions
Authors: Niegodajew Paweł , Asendrych Dariusz , Drobniak Stanisław 
Published: January 2014

Abstract
The paper deals with the computational fluid dynamics modelling of carbon dioxide capture from flue gases in the post combustioncapture method, one of the available carbon capture and storage technologies. 30% aqueous monoethanolamine solution was used as a solvent in absorption process. The complex flow system including multiphase countercurrent streams with chemical reaction and heat transfer was considered to resolve the CO2 absorption. The simulation results have shown the realistic behaviour and good consistency with experimental data. The model was employed to analyse the influence of liquid to gas ratio on CO2 capture efficiency.
ENERGY POTENTIAL IN PRODUCTION OF FAST-GROWING POPLAR CLONES IN SLOVAK REGIONS
Authors: Petráš Rudolf , Mecko Julian , Petrášová Viera 
Published: January 2014

Abstract
Calorific value production from the above-ground biomass of stands was derived from its volume production. The mathematical models of growth tables of I-214 and Robusta poplar clones, biomass density values and calorific values of biomass dry matter were used for its calculation. At the stands aged 35 years and site indices of 20, 30 and 40, the calorific value has approximately 2.700, 6.000 and 9.300 GJ.ha-1 respectively. The I-214 clone has higher production than Robusta in the first half of its growth, albeit with minimum differences. The annual increments of calorific value culminate about the age of 9-13 years with values of 450-115 GJ.ha-1. Mean annual production of both clones culminates at the age of 17-26 years with values of 320-80 GJ.ha-1. Lowland forest locations with high level of ground water in Slovakia with the total area of 25.600 ha are most suitable for poplars production. On this area, we can assume the mean annual production of 3.566 TJ of gross calorific value obtained from above-ground biomass in the future. From that, about 64% is in wood, 14% in bark and 22% in small-wood. Up to 85% of this production potential is situated in the area of The Danube Lowland and the rest is mainly in southern areas of the Central and Eastern Slovakia.
Effect of Temperature and Used Ingredients on Rheological Parameters of Pancake Dough
Authors: Hlaváč Peter , Božiková Monika 
Published: January 2014

Abstract
This paper presents the selected rheological properties of pancake dough such as dynamic and kinematic viscosity and fluidity. The effect of used ingredients and temperature on rheological properties is investigated. Measurements were performed on three pancake dough samples. In two samples, there was used milk with a different fat content, and in the third sample, all ingredients were in a powder state. A digital rotational viscometer Anton Paar DV-3P was used for measuring the rheological properties. The principle of viscometer measurement is based on the dependence of sample resistance to probe rotation. Results of measurements are shown as graphical dependencies of rheological parameters on temperature. Exponential functions were used to express the dependencies of all rheological parameters on temperature. Dynamic and kinematic viscosity decreased, and fluidity increased with temperature. The highest values of dynamic viscosity were obtained for pancake dough from powder ingredients. A higher fat content of used milk caused higher values of dynamic viscosity.
Cutting Process Capability Study
Authors: Škůrková Katarína Lestyánszka , Žarnovský Jozef 
Published: January 2014

Abstract
This study focuses on the evaluation of cutting process capability in the production of printed circuit boards according to regulation defined by ISO 9001: 2008 Quality Management Systems. Requirements. Therefore, statistical process control is analysed on the basis of normality and stability of the process, and cutting process capability indices Cp and Cpk are calculated. The values obtained for indices are Cp = 6.801 and Cpk = 5.499. Therefore, we can consider the process as capable.
Increasing calculation accuracy in the design stage of a gas transportation system
Authors: Neacşu Sorin , Rădulescu Renata 
Published: January 2014

AbstractThe paper presents a critical evaluation of the equations used to calculate the flow and pressure for transport pipelines. A highly accurate method for calculating gas parameters is proposed. The final part of the paper presents some comparisons between the proposed method and modern simulators used for the design of transport systems.