bluuebunny/crossref_metadata_2025 huggingface dataset:
JOINING THE COMBINATION OF AHSS STEEL AND HSLA STEEL BY RESISTANCE SPOT WELDING
Authors: Kaščák Ľuboš , Spišák Emil , Gajdoš Ivan
Published: January 2014

The paper deals with the optimization of parameters of resistance spot welding and quality analysis of welded joints made by combination of galvanized Advanced High Strength Steel and High Strength Low Alloy steel. It is an advanced material combination utilized in automotive industry to reduce weight of the vehicle body and consequently lowering the fuel consumption to achieve the lowest possible fuel consumption, high active and passive safety of passengers while decreasing the amount of emission. The quality of welded joints was evaluated by destructive tests and non-destructive tests. The shear tensile test according to STN 05 1122 standard was used. Some samples were prepared for metallographic analysis, where the influence of the welding parameters on the structure of welded joint and occurrence of pores in the weld metal caused by evaporation of zinc from the coating was observed.
AIR FLOW ANALYSIS FOR ELECTRICAL MOTOR'S COOLING SYSTEM WITH AUTODESK SIMULATION CFD 2013 PROGRAM
Authors: Madej Jerzy , Będkowski Bartłomiej
Published: January 2014

In the article the analysis of airflow through electrical motor was conducted and optimal design solution was chosen in order to increase cooling efficiency. Numerical simulations allow to determine the areas of temperature occurrence which may have destructive influence on electrical motor parts and on its safe operation. The numerical calculations of airflow was carried out for two different types of fans as well as for two different housings. An analysis of the construction was carried out by CFD method using Autodesk Simulation CFD 2013. Community results of the analysis, we can conclude that the better solution for machines with fixed direction of rotation is to use instead of the radial the axial fan. For axial fan the motor temperature in the same condition was lower by about 5°C.
EFFECT OF HEAT TREATMENT AND PLASMA NITRIDING ON CORROSION RESISTANCE OF 440B MARTENSITIC STAINLESS STEEL
Authors: Łępicka Magdalena , Grądzka-Dahlke Małgorzata
Published: January 2014

Reliability and durability assurance poses a serious challenge for surgical instruments manufacturers. Hard working conditions, such as intermittent contact with body fluids and hard bone tissues, as well as necessity to undergo frequent sterilisation processes, induce constant research into solutions capable of ensuring high wear resistance while maintaining satisfactory imperviousness to corrosion. Plasma nitriding is marked as the modern corrosion resistance improving method suitable for surgical instruments steels. The paper presents findings from the heat treated and plasma nitrided AISI 440B (PN EN or DIN X90CrMoV18) steel corrosion resistance studies. Three conventionally heat treated (quenched with tempering in 250, 390 or 605°C) and three additionally plasma nitrided in N2:H2 reaction gas mixture (50:50, 35:65 and 20:80 ratio, respectively) specimens groups were examined. Furthermore, the authors evaluated the effect of machining - polishing and sandblasting - on investigated steel corrosion resistance. Microscopic observations and electrochemical corrosion tests were performed using a variety of analytical techniques. Results showed that, in comparison to conventional heat treatment, plasma nitriding of 440B stainless steel does not significantly affect its corrosive characteristics as far as the uniform nitride layer over the entire detail surface is obtained. The layer heterogeneity results in intensification of corrosion processes, making the material even more susceptible to corrosion than after conventional heat treatment, and contributing to severe, visible even with the unaided eye damages development.
ANALYSIS OF TRIBOLOGICAL PROCESSES IN THE INKING UNIT OF THE OFFSET PRINTING MACHINE
Authors: Pyryev Yuriy , Piętak Zofia Maria
Published: January 2014

In this paper is proposed the mathematical description of the temperature distribution resulting from the friction between the two inking rollers (one of which is made off steel and the second one has elastic layer) in the offset printing machine. So-called in printing industry steel vibrator roller perform simultaneously rotary and reciprocating motion. This reciprocating motion is the main source of the heat generation. Using the Laplace transform method for heat conduction equations with boundary conditions taking into account the real processes taking place in the inking unit in contact area we obtained and analyzed the solution that could be useful for determination and regulation of parameters in order to decrease time of process stabilization
Impact of Tin and Nickel on the Brazing Properties of Silver Filler Metals and on the Strength of Brazed Joints Made of Stainless Steels
Authors: Winiowski A. , Rózanski M.
Published: January 2014

The research involved vacuum tests of brazing properties of silver filler metals, containing tin as well as tin and nickel, and used in brazing of chromium X6Cr17 and chromium-nickel X6CrNiTi18-10 stainless steels. The research also involved testing the strength and structural properties of brazed joints made of these steels. The tests were conducted on filler metals (silver brazing alloys) B-Ag68CuSn-730/755 (Ag68Cu28Sn4) and B-Ag65CuSnNi-740/767 (Ag65Cu28Sn5Ni2) and also, for comparative purposes, on the filler metal B-Ag72Cu-780 (Ag 272 according to PN-EN ISO 17672), most commonly applied in the vacuum brazing of high alloyed stainless steels. The brazing properties of the filler metals were tested by determining their wettability by means of the spreadability method. The strength of brazed joints made of the stainless steels was examined in a shear test. Research-related structural tests involved light and electron microscopy with an energy dispersive spectrometer (EDS). The comparative analysis of the properties of the filler metals revealed the positive impact of tin and nickel on the spreadability and wettability of the silver brazing alloys as well as on the quality and the shear strength of brazed joints.
Effect of Synergic Controlled Pulsed and Manual Gas Metal ARC Welding Processes on Mechanical and Metallurgical Properties of AISI 430 Ferritic Stainless Steel
Authors: Teker T.
Published: January 2014

The gas metal arc is widely used in manufacturing industries because of the high metal deposition rate and ease of automation with better weld quality at permissible cost than other welding processes in joining similar and dissimilar metals. AISI 430 steel is normally difficult to weld by melting methods, due to the associated problems such as grain growth. For this purpose, AISI 430 ferritic stainless steel couples of 10 mm thick were welded by the synergic controlled pulsed (GMAW-P) and manual gas metal arc (GMAW) welding techniques. The interface appearances of the welded specimens were examined by scanning electron microscopy (SEM). Structural changes in the weld zone were analysed by energy dispersive spectrometry (EDS) and X-ray diffraction (X-RD). Microhardness, notch charpy and tensile tests were conducted to determine the mechanical properties of specimens. Accordingly, the best result was obtained from the GMAW-P technique.
Analysis of the New Solution of the Vibratory Conveyor
Authors: Czubak P.
Published: January 2014

It was noticed, in industrial practice, that in typical vibratory conveyors suspended on the coil springs system and driven by two self-synchronising vibrators their dissynchronisation can lead to local elevations of loose feed and in extreme cases to the arrestment of a feed flow from the machine or even to the reversal of its transportation direction along the body. The new structural solution of the vibratory conveyor which, in spite of disphasing of vibrators, enables the feed material transport along the trough with a constant velocity, was presented and analysed in the paper
Mathematical Modelling of the High Frequency Vibrations During Cold Rolling Process
Authors: Światoniowski A. , Bar O.
Published: January 2014

The study explores the model of high-frequency vibrations during the continuous rolling processes, the underlying assumption being that vibrations are self-excited. The effects of rolling stand and rolling process parameters on the nature and intensity of vibrations are investigated. The appearance of darkened streaks occurring on the metal sheet is explained. The results are compared with the data quoted in literature on the subject.
The Effect of Secondary Metalworking Processes on Susceptibility of Aircraft to Catastrophic Failures and Prevention Methods
Authors: Dzidowski E.S.
Published: January 2014

The causes of plane crashes, stemming from the subcritical growth of fatigue cracks, are examined. It is found that the crashes occurred mainly because of the negligence of the defects arising in the course of secondary metalworking processes. It is shown that it is possible to prevent such damage, i.e. voids, wedge cracks, grain boundary cracks, adiabatic shear bands and flow localization, through the use of processing maps indicating the ranges in which the above defects arise and the ranges in which safe deformation mechanisms, such as deformation in dynamic recrystallization conditions, superplasticity, globularization and dynamic recovery, occur. Thanks to the use of such maps the processes can be optimized by selecting proper deformation rates and forming temperatures.
Forming Limit Diagram of the AMS 5599 Sheet Metal
Authors: Fracz W. , Stachowicz F. , Trzepieciński T. , Pieją T.
Published: January 2014

Formability of sheet metal is dependent on the mechanical properties. Some materials form better than others - moreover, a material that has the best formability for one stamping may behave very poorly in a stamping of another configuration. For these reasons, extensive test programs are often carried out in an attempt to correlate material formability with value of some mechanical properties. The formability of sheet metal has frequently been expressed by the value of strain hardening exponent and plastic anisotropy ratio. The stress-strain and hardening behaviour of a material is very important in determining its resistance to plastic instability. However experimental studies of formability of various materials have revealed basic differences in behaviour, such as the ”brass-type” and the ”steel-type”, exhibiting respectively, zero and positive dependence of forming limit on the strain ratio. In this study mechanical properties and the Forming Limit Diagram of the AMS 5599 sheet metal were determined using uniaxial tensile test and Marciniak’s flat bottomed punch test respectively. Different methods were used for the FLD calculation - results of these calculations were compared with experimental results
The Analysis of Stress States in Steel Rods Surfaced by Welding
Authors: Winczek J.
Published: January 2014

In work is presented a method of calculating elasto-plastic states in thermally loaded rods, which takes into account phase transformations that occur during surfacing by welding. Kinetics of phase transformations during heating and cooling is limited by temperature values at the beginning and at the end of austenitic transformation, while the progress of phase transformations during cooling is determined on the basis of TTT-welding diagram, basing on Johnson-Mehl-Avrami-Kolomogorov law for diffusional transformations and Koistinen-Marburger for martensitic transformation. Stress state of a bar subjected to thermo-mechanical loads is described assuming the planar cross section hypothesis and using integral equations of stress equilibrium of a bar as well as simple Hook’s law. Dependence of stresses from strains is assumed on the basis of tensile curves of particular structures, taking into account the influence of temperature. Computations of strains and stresses are investigated in a rod made of S235 steel, loaded by thermal fields generated by a point welding heat source of different intensities. The analysis of origination and development of plastic strains is carried out. In order to verify correctness of the model, experimental tests are carried out on a rod made of S235 steel surfaced with GMA method with geometry and welding parameters assumed in numerical simulations. Residual stresses, calculated taking into account phase transformations and for homogenous material model, are compared with experimental results.
The Effect of Nano SiO2 Particle Size Distribution on Rheological Behaviour of Shear Thickening Fluids
Authors: Idźkowska A. , Szafran M.
Published: January 2014

In present work the influence of particle size distribution on the dilatant effect of shear thickening fluid was investigated. As a ceramic powder a mixture of silicas 200 and 7 nm in ratio 95:5, 90:10, 85:15, 80:20, 75:25, 50:50 was used. A dispersing agent was poly (propylene glycol) of a molecular weight of 425 g/mol. The as prepared slurries were examined on a rotational rheometer Kinexus Pro with a plate-plate measuring system at room temperature, where the viscosity as a function of shear rate was investigated. The measurement showed that by partially replacing greater particle size by smaller one, it is possible to shift the onset of shear thickening to the higher value of shear rate, however, the decreases of dilatant effect is observed. The influence of particle size distribution on a maximum volume fraction also was investigated. The maximum volume fraction which was passible to obtain was 35 vol%.
Photothermal Transformation In Heterogeneous Semiconductors Structures Under Its Pulse Laser Irradiation: Role Of Electron-Hole Diffusion
Authors: Isaiev M. , Kuryliuk V. , Kuzmich A. , Burbelo R.
Published: January 2014

In this paper photothermal transformation in semiconductor structures with modified properties of subsurface layer under its irradiation by pulse laser (~10 ns) radiation was analyzed. It was show that the presence of this surface modified layer leads to increasing of surface temperature in comparison with homogeneous case. Moreover, this increasing could even compensate the temperature decreasing induced by thermal source redistribution caused by charge carrier diffusion.
Some Structural Aspects of Ionic Conductivity in Co-Doped Ceria-Based Electrolytes
Authors: Dudek M.
Published: January 2014

The sinters of co-doped ceria solid solutions with the formula of Ce0.85Sm0.15-x RxO1.9, where R = Y, Gd, Pr, Tb, Ox-0.15, were obtained from powders synthesised by Pechini method. The linear variation of cell parameter a vs. chemical composition was observed for Ce0.85Sm0:15-xRxO1.9, where R = Y, Gd, Tb, 0 <x<0.15 samples. However, the introduction of Pr3+ into Ce0.85Sm0.15-x PrxO1.9 caused a small deviation from linearity due to possible changes in the valence from Pr3+ to Pr4+. The determined values of oxide transference number tion for Ce0.85Sm0.15-xRxO1.9, R = Y, Gd in the temperature range 400-750°C and partial oxygen pressure from 10-6 to 1 atm were close to 1, which indicated that materials investigated exhibited practically pure ionic oxide conductivity. On the other hand, the introduction of Tb3+ or Pr3+ higher than x>0.05 into solid solution Ce0.85Sm0.15-xRxO1.9, R = Tb, Pr caused a decrease in the ionic transference number tion below 1 due to an increase in partial electronic conduction. This fact limiting investigated co-doped terbia and samaria or samaria and praseodymia ceria-based solid solutions for the further application as oxide electrolytes in solid oxide fuel cells. The analysis of bulk and grain boundary values indicated that partial substitution of Sm3+ by Y3+ or Gd3+ caused slight improvements in the ionic conductivity of Ce0.85Sm0.15-xRxO1.9. The highest ionic conductivity was found for solid solution with chemical composition Ce0.85Sm0.1Y0.05O1.9. The selected co-doped ceria samples were tested as solid electrolytes in solid oxide fuel cells operating in the intermediate temperature range 500-750°C.
Technology and Electrophysical Properties of Multiferroic PZT–PFT Ceramics
Authors: Niemiec P. , Skulski R. , Bochenek D. , Wawrzała P.
Published: January 2014

We present the results of obtaining and investigating ceramic samples of solid solution (1-x)(PbZr0.53Ti0.47O3)- x(PbFe0.5Ta0.5O3) [i.e. (1-x)PZT-xPFT] with x =0.25, 0.35 and 0.45 obtained using conventional ceramic technology. These materials belong to class of materials known as multiferroics. Solid solutions PZT-PFT are the lowest-loss room-temperature multiferroics known, and as a result there are very interesting for magnetoelectric devices. Paper presents the results of termogravimetric investigations, EDS, XRD and main dielectric measurements. It has been stated that with increasing content of PFT decreases the mean diameter of grains and more wide distribution of grain diameters is observed. For x =0.25 sharp phase transition from ferroelectric phase to paraelectric one is observed and high values of dielectric permittivity. Composition PZT-PFT with x =0.45 has the lowest values of dielectric permittivity, and the transition is more diffused. The increase of x leads also to the shift of the temperature of maximum of dielectric permittivity towards lower temperatures. Samples with x =0.25 and x =0.35 exhibit very low values of dielectric losses up to about 100°C. Dielectric losses for samples with x =0.45 are higher. For obtained PZT-PFT samples we have investigated P-E hysteresis loops at room temperature for frequency 1 Hz. For composition x =0.25 it after application the field about 2.5 kV/mm polarization is equal approximately 28 μC/cm2, while for x =0.35, and x =0.45 after application the field about 2.0 kV/mm the polarizations are equal about 25 μC/cm2 and 20 μC/cm2 respectively. Very low values of losses and high values of polarization lead to the conclusion that interesting material PZT-PFT for applications should be composition with x =0.25.
The Influence of Fabrication Conditions on the Physical Properties of PLZT:Nd3+ Ceramics
Authors: Płonska M. , Pisarski W.A. , Wodecka-Dus B. , Czekaj D.
Published: January 2014

The aim of this work was to study the effect of fabrication conditions and neodymium co-doping on the physical properties of (Pb0:98La0:02)(Zr0:65Ti0:35)0:98O3, known as PLZT:Nd3+ ceramics. All ceramic powders of these materials were synthesized by the conventional mixed oxide method, from the high purity raw materials (>99.9%). The bulk ceramic samples were sintered by the pressure less sintering and the hot-uniaxial pressing techniques. The study gives a detailed account of the relationships between doping and preparing conditions on the dielectric and optical properties of obtained ceramic materials. Optimal conditions of PLZT:Nd3+ preparation as well as Nd3+ activator concentration were determined in relation to the potential opto-electronic applications.
Effect ofSolvents on Curing Process of Photopolymerizable Ceramic Suspensions
Authors: Falkowski P. , Grzelak A.
Published: January 2014

The effect of solvent on rheological properties and way of preparation of ceramic suspensions or dispersions was presented. The research showed that in case of applied polyester resin the water cannot be used in preparation of UV curable suspensions. However, the highly loaded ceramic dispersion in UV curable media can be prepared if the water is replaced by PEG. Thus, the dispersions with good homogeneity and solids content up to 45-50vol.% of alumina can be obtained. The dispersion prepared in this way can be tape casted and UV cured.
IN-SITU TREATMENT OF GROUNDWATER CONTAMINATED WITH UNDERGROUND COAL GASIFICATION PRODUCTS / OCZYSZCZANIE IN-SITU WÓD PODZIEMNYCH ZANIECZYSZCZONYCH PRZEZ PRODUKTY PODZIEMNEGO ZGAZOWANIA WĘGLA
Authors: Suponik Tomasz , Lutyński Marcin
Published: January 2014

In the paper the contaminants that may be generated in Underground Coal Gasification (UCG) process were listed and include mainly mono- and polycyclic aromatic hydrocarbons, phenols, heavy metals, cyanides, ammonium, chloride and sulphate. As a method of UCG contaminated groundwater treatment a Permeable Reactive Barrier technology was proposed. To assess the effectiveness of this technology two tests were carried out. Granulated activated carbon (GAC) and zeolite, and granulated activated carbon and scrap iron were applied in the first and second test respectively. For these materials the hydro geological parameters called reactive material parameters were determined and discussed. The results of the experiments showed that GAC seems to be the most effective material for phenols, BTX, PAH, cyanides and slightly lowers ammonia removal, while zeolites and scrap iron removed free cyanide, ammonia and heavy metals respectively.
THE IDENTIFICATION OF PARAMETERS OF THEORIES USED FOR PROGNOSES OF POST MINING DEFORMATIONS BY MEANS OF PRESENT SOFTWARE / IDENTYFIKACJA WARTOŚCI PARAMETRÓW TEORII PROGNOZOWANIA WPŁYWÓW PRZY WYKORZYSTANIU WSPÓŁCZESNYCH NARZĘDZI INFORMATYCZNYCH
Authors: Ścigała Roman
Published: January 2014

The characteristic of specialized computer programs has been presented, serving for identification of W. Budryk-S. Knothe theory parameters, used for description of asymptotic state of post-mining deformations, as well as for transient state. The software is the result of several years of authors’ work. It is a part of complete software system designed for forecasting of underground mining influences on the rock mass and land surface and graphical processing of calculations results. Apart from software description, a short example of its practical utilization has been attached.
EVALUATION OF DRY MATTER PRODUCTION OF MISCANTHUS SINENSIS (TATAI) IN THE CONDITIONS OF SOUTH-WESTERN SLOVAKIA
Authors: Prčík Martin , Kotrla Marián
Published: January 2014

In this paper, we present the results of research of phytomass production allocated to aboveground organs, leaves and stalks, after the third growing year. The research was conducted in the field experiment conditions of Farm holding in Kolíňany. The results of the aboveground dry matter production are expressed in tonnes of dry weight produced on the area of one hectare (t.ha-1). The total dry weight of the aboveground biomass was 6.89 t.ha-1 at the end of the first growing year 2010. In the growing year 2011, it reached 15.21 t.ha-1 (an increase by 121 %.) The total dry weight of the aboveground phytomass increased by 37% compared to 2011, and it reached 20.82 t.ha-1 in the third growing year (2012). The increase of phytomass is directly proportional to off shoot circle. Average off shoot circle of individuals in the first growing year was 300 mm and the average number of stems produced in a clump was 37.60. In 2011, the average off shoot circle of individuals was 502 mm and there were 43.73 stems created in a clump. In the third growing period of 2013, the extension of the off shoot circle by 113.7% (641 mm) was registered in comparison with 2010 and the amount of 80.19 stems per clump was recorded.
BIOGAS PRODUCTION FROM AMARANTH BIOMASS
Authors: Sitkey Vladimír , Gaduš Ján , Kliský Ľubomír , Dudák Alexander
Published: January 2014

Energy variety of amaranth (Amaranthus spp.) was grown in large-scale trials in order to verify the capability of its cultivation and use as a renewable energy source in a biogas plant. The possibility of biogas production using anaerobic co-fermentation of manure and amaranth silage was verified in the experimental horizontal fermentor of 5 m3 volume, working at mesophilic conditions of 38-40 °C. The goal of the work was also to identify the optimum conditions for growth, harvesting and preservation of amaranth biomass, to optimize biogas production process, and to test the residual slurry from digestion process as a high quality organic fertilizer. The average yield of green amaranth biomass was 51.66 t.ha-1 with dry matter content of 37%. Based on the reached results it can be concluded that amaranth silage, solely or together with another organic materials of agricultural origin, is a suitable raw material for biogas production.
THE INFLUENCE OF YEAR-ROUND WEATHER CONDITIONS AND FERTILIZATION ON THE PHYTOMASS YIELD OF AMARANTH (AMARANTHUS L.)
Authors: Illéš Ladislav , Candráková Eva , Pospišil Richard , Žembery Jozef
Published: January 2014

In the years 2010 and 2011, a field trial was established in the administrative area Kolinany, Barack farm. We evaluated the growth of aboveground phytomass depending on different levels of fertilization. In the climatically unbalanced growing years, the phytomass yield of amaranth was different. Extremely wet conditions during the growing season exceeding long-term normal precipitation confirmed the assumption of high growth of aboveground phytomass in the observed amaranth genotype. In 2010, the highest amaranth aboveground dry matter in phytomass reached 3231.40 g m2 in the variant with the fertilization dose of 150 kg ha-1. In the climatically different year 2011 with lower precipitation, the highest aboveground phytomass yield of 3956.95 g m2 was reached in the fertilized variant as well.
Impact of Multipath GPS Signal Spreading on Precision of Us er Localization
Authors: Chrastina Jozef , Polonec Tomáš , Janoško Ivan , Tulík Juraj
Published: January 2014

This paper focuses on measuring the inaccuracy of localization using a global positioning system. It describes the types and causes of navigation errors as well as the impact of multipath signal spreading on determining the GPS location. The aim of the experiment is to quantify the degree of influence of GPS multipath signal spreading in urban environments compared with measurements in the open air. During the experiment, we have used a Holux M-1000C GPS device in the DGPS / SBAS mode using the EGNOS technology.
In vivo quercetol effect in lead acetate poisoning
Authors: Roncea Florentina , Miresan Horatiu , Rosca Adrian Cosmin , Bratu Mihaela , Popescu Antoanela
Published: January 2014

The present study investigated the influence of quercetol upon δ-aminolevulinic acid (△ -ALA) urine concentration as marker of lead poisoning. The study was conducted on six lots of 6 mature Wistar rats of both sexes, lots not poisoned treated with different concentrations of quercetol (Q1, Q2), control (L6M), lot poisoned untreated (L3Pb), lots poisoned and treated with Q (L4Q1Pb and L5Q2Pb). After 11 days urine from 24 hours was collected for △-ALA spectrophotometric assay and testing the significance of mean difference of by "t" test Student at p <0.05. Statistical analysis of the data presented shows that compared to L2Q2 and L6M the amount of δ-ALA excreted in urine under quercetol influence (L4Q1Pb) shows statistical significance compared to (L2Q2) the amount of δ-ALA excreted in urine compared to (L3Pb) shows statistical significance. Different concentrations of quercetol (Q1, Q2), did not produce significant changes in the δ-ALA excreted compared with values of (L3Pb). Difference between means is probably due to sampling fluctuation, is not significant, reduced growth to eliminate δ-ALA on L4Q1Pb and L5Q2Pb is believed to be due to iron complex formation, reducing hemoglobin synthesis. From the results we conclude that hem biosynthesis does not start to grow under quercetol protection. The obtained data are not relevant statistical since interpretations were performed on non homogeneous groups in number of individuals, the percentage of mortality variability and high levels of standard deviation calculated from each lot.
The dynamic simulation of the natural gas transportation
Authors: Eparu Cristian , Rădulescu Renata , Stoica Doru
Published: January 2014

The natural gas consumption of the operators connected to the gas transport system depends on the gas needs. As gas needs vary in time, the whole process of gas transportation is, therefore, nonstationary. The paper presents nonstationary simulations for a gas transportation network and highlights the parameters values (flows, pressures) that are necessary to assure the safety of the system.
Environmental pollution in the petroleum refining industry
Authors: Damian Cristina
Published: January 2014

The petroleum refining industry has a significant influence on the total pollution of the environment by industrial discharges and wastes. In the operation of petroleum refineries, the atmosphere is polluted with hydrogen sulfide, sulfur dioxide, nitrogen oxides, carbon monoxide, hydrocarbons, and other toxic substances. The main pollutants are sulfur dioxide and hydrocarbons. The fresh water used by refineries in product cooling is returned to the original source of water containing crude oil, petroleum products, and mineral salts as contaminants. The extent of air and water pollution depends on the particular processing technology, control measures that are employed and also on the scale of the processing. In working out these measures, the primary attention of scientific-research institutes and design and planning organizations must be directed not only towards how to reduce the contaminating and poisoning action of industrial discharges on the environment, but primarily towards preventing or minimizing these discharges in the refineries.
Mathematical model for power consumption at mixing of industrial and domestic wastewater sludge
Authors: Sterpu Ancaelena Eliza , Koncsag Claudia Irina , Dumitru Anca Iuliana , Mihalcea Alina-Daniela
Published: January 2014

Physical investigations have been carried out to characterize the power consumption in a laboratory autoclave vessel equipped with an anchor impeller (diameter d = 0.068 mm), without baffles, at 8 speed ratio, from 100 to 800 rpm. The laminar flow regime was investigated using sludge proceeding from the treatment of mixed industrial and domestic wastewater, with a view to its subsequent processing: mixing, filtration, dewatering. The mathematical modeling focused on finding an accurate equation linking the Power number (Np) and the Reynolds number (Re) at different levels (H) of sludge in the vessel.

The rheological curves indicate that the sludge have non-Newtonian behaviors which are better described by the Herschel-Buckley model. The models resulted from the Np variation versus Re are power function type Np = a ×Reb , where the coefficient a is a linear functions of H/d ratio and b = -1.016 have a constant value.
The framing of the raw materials used for manufacturing some rough ceramic materials into polinary oxide systems
Authors: Szöke Anna-Maria
Published: January 2014

In this paper it is presented the framing into polinary oxide systems in the case of optimal design of the oxide composition for obtaining raw ceramic materials. These calculations were carried out on two raw materials, which were the base of the experimental researches, for finding out the potential mineralogical composition. It was also followed, for the two raw materials, the framing options of the composition in oxide systems and the assessment of their belongings to possible subsystems.
Quantification of sugar in different brands of drinks
Authors: Dobrinas Simona , Soceanu Alina , Stanciu Gabriela , Popescu Viorica
Published: January 2014

The levels of invert sugar (glucose/fructose mixture resulting from inversion) were determined in different brands of orange, grapefruit, lemon, apricot and raspberry products. Samples of fresh juice, soft drink, syrup, nectar and compote were representative of the Romanian market. The invert sugar was quantified by Ofner’s method (a titrimetric method) and the refractive and Brix indices were measured for the quantification of sucrose in studied samples. International Commission for Uniform Methods of Sugar Analysis accepts reading of sugar content based on the refractive properties of sucrose despite the fact that the sugar in analyzed juice sample is fructose, not sucrose. This usually does not result in significant error. There were significant differences among orange, grapefruit, lemon, apricot and raspberry products brands, in the levels of sugars.
The 3 vs 1 game build-up effectiveness examination in physical and technical tests of 11-year-old football players
Authors: Tóth jr. Janos , Zalai David , Tóth Janos , Hamar Pál
Published: January 2014

Study aim: The aim of this study is to prove that young players who have been coached with the main focus on technical ability and player interaction, perform better when tested on physical and technical attributes.

Material and methods: We examined 2 separate groups made up of 15 players each. After thorough analysis, the experimental group practiced playing forms to building up 3 vs 1 games weekly for one year. The control group did not follow this training pattern.

Results: Over the course of the year there was a constant development in all aspects of the examination. Furthermore, both physical and technical attributes were significantly better . The same cannot be concluded from the analysis of the control group, in which the performance level even dropped in some aspects of the examination.

Conclusion: The results show that players practicing the playing forms on a weekly basis performed better in physical and technical tests. In addition, subjective experience has also underlined the effect of the method.
Use of leaf morphometric parameters for identification of the most common cultivated intraspecific taxa of Tilia platyphyllos
Authors: Evarte-Bundere Gunta , Evarts-Bunders Pēteris
Published: January 2014

Evarte-Bundere G., Evarts-Bunders P., 2013: Use of leaf morphometric parameters for identification of the most common cultivated intraspecific taxa of Tilia platyphyllos [Morfometrinių požymių panaudojimas dažniausiems kultūriniams Tilia platyphyllos vidurūšiniams taksonams apibūdinti]. - Bot. Lith., 19(2): 83-90. To determine variation of the most important morphological parameters of Tilia platyphyllos Scop., we studied four most frequently found in Latvia taxa: T. platyphyllos subsp. platyphyllos, T. platyphyllos subsp. cordifolia (Besser) C.K.Schneid., T. platyphyllos ‘Rubra’, T. platyphyllos ‘Obliqua.’ Morphometric measurements (length of petioles, width and length of leaf blades, pubescence and margin of leaves) were performed for 10 different specimens of every selected taxon measuring five typical leaves from each specimen. The cultivated intraspecific taxa of Tilia platyphyllos differed by the following morphometric parameters - the pubescence of leaves, the margin of leaves and the length of leaf blades. No significant differences were ascertained between taxa in such morphometric parameters as the width of leaf blades and the length of petioles.
Notes on some new and interesting Greenland lichens with particular emphasis on high arctic taxa
Authors: Hansen Eric Steen
Published: January 2014

Hansen E. S., 2013: Notes on some new and interesting Greenland lichens with particular emphasis on high arctic taxa [Pastabos apie retas ir įdomias Grenlandijos kerpes, ypač poliarinių dykumų taksonus]. - Bot. Lith., 19(2): 149-156.

The paper lists 73 taxa of Greenland lichens. Immersaria athroocarpa, Melanelixia subaurifera and Polyblastia sakkobanensis are recorded for the first time from Greenland. Melanelia agnata, Melanohalea exasperatula and Peltigera britannica are new to South Greenland, while Miriquidica intrudens and Peltigera ponojensis are new to Central West Greenland. Caloplaca citrina, Cladonia galindezii, Pertusaria bryontha, Protoblastenia rupestris, Sphaerophorus globosus and Staurothele drummondii represent northern range extensions in North East Greenland. New localities north of 80° N are given for 59 lichen taxa from Greenland.
Different Successful Patterns for Implementing Holding Model in Public Sector
Authors: Todorović Ivan , Komazec Stefan , Čudanov Mladen
Published: January 2014

Background: Transitions in the modern business environment cause significant organizational changes not only in private companies, but also in the public sector. Introduction of an adequate organizational model for the public sector could improve the quality level of public services. Objectives: This article aims to present general benefits of the application of the holding organizational paradigm in the public sector through a parallel analysis of several cases that were observed individually in our previous research. The goal is to suggest possible restructuring directions to policy makers in cities where the public sector has not been adjusted to the changes in the modern business environment. Methods: The case study research based on the documentation analysis, interviews and direct observation using the standard management consulting practice provided an additional and deeper insight into the functioning of public enterprises in one European capital and one small municipality. Results: The examples presented in this paper showed that the application of the holding institutional solution in the public sector leads to an improved command, an increased level of control, reduced management costs, better allocation of city resources and decreased overheads in the public sector. Conclusions: Switching from a functional towards a network model of the organizational structure improved the performance of public enterprises and increased the quality of public services
Children’s university - a way to convince children to study science and technologies / Uniwersytet dziecięcy - droga przekonywania dzieci do studiowania nauk ścisłych i technologii
Authors: Dubová Markéta , Hernych Miloš
Published: January 2014

Technical University of Liberec implemented programs to attract pupils, high school students and first-year university students for study of technical and scientific disciplines. The first program is called “Children’s university” with the aim to convince elementary school pupils and secondary schools student. Children attend practical lectures and solve basic scientific tasks including work with real scientific equipment. They got exams for their activities and when passing all prescribed “lectures” they got a “diploma”. In addition to university examinations the Children’s University offers many different leisure activities, eg Open University, Walk for science and technology, Scientific cafes, Saturdays with technology. The main objective of the Children’s University is to catch talented individuals early and awaken their interest in university studies of technical and scientific disciplines in order to better direct their future professional orientation towards sectors with high added value, which the labour market has a long-term interest in. The second program, entitled “Scientific incubator”, is a follow-up programme to catch talented first-years university students for technical and scientific disciplines.
Water storage in anthropogenic lakes in southern Poland during high and low water stages / Retencja wody w jeziorach antropogennych południowej Polski w okresie wezbrań i niżówek
Authors: Rzętała Mariusz , Jaguś Andrzej , Rzętała Martyna A.
Published: January 2014

The central part of southern Poland is a land of anthropogenic lakes. Within an area of 6,766 km2 as many as 4,773 water bodies are present with a total area of 185.5 km2. Around a dozen of the largest water bodies serve flood protection purposes and are sources of water for municipal, industrial, agricultural, transport, energy purposes, etc. Such usage of these water bodies is the main reason for fluctuations in their water levels, although obviously these also depend directly on their supply (rainfall, groundwater drainage, water transfers), and indirectly on the size of their catchment areas and the degree to which their basins are full. The most spectacular changes in water levels occur during high and (less frequent) low water stages. Periodical rises in water levels related to high water episodes caused by thawing or rainfall reach as much as several metres compared to the period preceding the high water episode. Drought periods result in the lowering of storage levels towards minimum ones as does similarly the intentional discharge of water from reservoirs. In water bodies in southern Poland, annual changes in water levels range from several centimetres to almost ten metres. The variability of levels is often similar to the average depth of the water body in question, in some cases approaching its maximum depth. It determines the changes in the water retention, unprecedented for natural lakes.
BLENDING CHARACTERISTICS OF HIGH-SPEED ROTARY IMPELLERS
Authors: Fořt Ivan , Seichter Pavel , Pešl Luboš , Rieger František , Jirout Tomáš
Published: January 2014

This paper presents a comparison of the blending efficiency of eight high-speed rotary impellers in a fully baffled cylindrical vessel under the turbulent flow regime of agitated charge. Results of carried out experiments (blending time and impeller power input) confirm that the down pumping axial flow impellers exhibit better blending efficiency than the high-speed rotary impellers with prevailing radial discharge flow. It follows from presented results that, especially for large scale industrial realisations, the axial flow impellers with profiled blades bring maximum energy savings in comparison with the standard impellers with inclined flat blades (pitched blade impellers).
OPTIMAL STATE ESTIMATION AND ON-LINE OPTIMISATION OF A BIOCHEMICAL REACTOR
Authors: Satya Eswari Jujjavarapu , Anand Polumati , Venkateswarlu Chimmiri
Published: January 2014

An on-line optimising control strategy involving a two level extended Kalman filter (EKF) for dynamic model identification and a functional conjugate gradient method for determining optimal operating condition is proposed and applied to a biochemical reactor. The optimiser incorporates the identified model and determines the optimal operating condition while maximising the process performance. This strategy is computationally advantageous as it involves separate estimation of states and process parameters in reduced dimensions. In addition to assisting on-line dynamic optimisation, the estimated time varying uncertain process parameter information can also be useful for continuous monitoring of the process. This strategy ensures that the biochemical reactor is operated at the optimal operation while taking care of the disturbances that are encountered during operation. The simulation results demonstrate the usefulness of the two level EKF assisted dynamic optimizer for on-line optimising control of uncertain nonlinear biochemical systems.
Loss Reduction Method for the Isolated qZS-based DC/DC Converter
Authors: Zakis Janis , Rankis Ivars , Liivik Liisa
Published: January 2014

This paper presents an isolated quasi-Z-source inverter-based (qZSI) resonant DC/DC converter. The explanation of selection of the proposed topology is justified. Both the normal and the boost modes are discussed. Theoretical operation waveforms as well as basic expressions for the calculation of currents and voltages are proposed. A 1500 W laboratory prototype was built and experimentally verified at two operation points: that of light-load (300 W) and full-load (1500 W). All the experiments were also carried with resonant circuit and without it. The experimental results as well as performance of proposed qZSI based resonant DC/DC converter laboratory setup are presented and analyzed. Experimental and calculated characteristics showing the dependence of the load voltage and supply current on the load resistance in both modes were presented. The dynamic losses in the transistors were evaluated for the cases with the resonant circuit and without it. The main conclusions based on this study are summarized and the future tasks for development of proposed converter were defined.
The Re-examination of Adjustment of the Rotor Magnetic Field Observer in the Induction Motor
Authors: Burkov Alexander , Krasilnikyants Evgenii , Smirnov Alexander , Bouldukan Georgy
Published: January 2014

Wide use of induction motor drives makes the problems related to induction motors very topical. One of such problems is the maximal utilization of torque and velocity of induction motors. In this regard the use and accurate adjustment of rotor magnetic flux observers may be helpful. The technique of observer adjustment is subject of special interest. This technique can be regarded as optimal if it ensures constant acceleration that, in turn, corresponds to constant magnitude of active and magnetizing components of stator current. In contrast, nonoptimal tuning of the magnetic flux observer creates a transient response caused by variation of magnetic and active components of the stator current resulting in changing acceleration of the motor. However, the parameters of non-optimal process can be used for fine tuning of the observer which considers the variation of the time constants obtained analyzing the drive's magnetic circuit saturation. It is possible to conclude that implementation of fine adjustment of rotor magnetic flux observer is of critical importance for induction motor torque and velocity maximum utilization.
INORGANIC MICROPOLLUTANTS REMOVAL BY MEANS OF MEMBRANE PROCESSES - STATE OF THE ART
Authors: Bodzek Michał
Published: January 2014

A number of inorganic anions and metals, especially heavy metals, at certain conditions, have been found in potentially harmful concentrations in numerous water sources. The maximum permissible levels of these compounds, in drinking water and wastewaters discharged to environment, set by the WHO and a number of countries are very low (from μg/dm3 to a few mg/dm3). Several common treatment technologies, which are nowadays used for removal of inorganic contaminants from natural water supplies, represent serious exploitation problems. Membrane processes such as reverse osmosis and nanofiltration, ultrafiltration and microfiltration in integrated systems, Donnan dialysis and electrodialysis as well as membrane bioreactors, if properly selected, offer the advantage of producing high quality drinking water without inorganic substances as well as purified wastewater which can be drained off to natural water sources
THE USE OF NEUTRON ACTIVATION ANALYSIS IN THE BIOMONITORING OF TRACE ELEMENT DEPOSITION IN THE OPOLE PROVINCE
Authors: Kłos Andrzej , Aleksiayenak Yulia A. , Ziembik Zbigniew , Rajfur Małgorzata , Jerz Dominik , Wacławek Maria , Frontasyeva Marina V.
Published: January 2014

The neutron activation analysis procedure was used to determine the concentration of 42 elements: Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Ni, Co, Zn, As, Se, Br, Rb, Sr, Zr, Nb, Mo, I, Ag, Cd, Sb, Ba, Cs, La, Ce, Nd, Sm, Eu, Tb, Yb, Hf, Ta, W, Au, Hg, Th, and U accumulated in mosses sampled for testing in September and October 2011 in the Opole Province (Southern Poland). Samples of different moss species were collected near the intersections of the grid lines marked on the map of the province. The distance between the points was approximately 20 km. The analysis of the results made it possible to identify the places of increased deposition of element-pollutants and to indicate the potential sources of emission. Factor analysis revealed four components, two of which are of definite anthropogenic origin. The possible sources of elements are local industry and farming, and distant heavy industry complexes. The results have demonstrated the increased content of Cr, Cd, Hg, and U in moss samples collected in agricultural areas located in the southern part of the province. It has been concluded that the industrial areas of Rybnik and Ostrava and Karvina Coal Basin may be the potential source of emission of these elements.