bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of nanostructured CeO2 with dyes adsorption property
Authors: Zuas Oman , Abimanyu Haznan , Wibowo Widayanti
Published: April 2014

The nanostructured cerium dioxide (CeO2) has been successfully fabricated
using a simple precipitation method. Its characteristics were evaluated using
TG-DTA, DR-UV-Vis, XRD, FTIR and TEM. The results showed that the
nanostructured CeO2 has high purity and good crystalline nature, with face
centered cubic (fcc) phase and the average diameter of CeO2 single crystal
about 14 nm. Performance evaluation of the synthesized CeO2 samples showed
that the nanostructured CeO2 has a strong adsorption toward acid orange-10
(AO-10) and congo red (CR) in aqueous solution. Under given experimental
conditions (dye concentration of 15 mg/l, adsorbent dosage of 1 g/l, reaction
temperature of 30 ? 1?C), it was estimated that the adsorption equilibrium
for AO-10 and CR occurred at 60 min and 90 min of reaction time,
respectively, with total removal of 96.82% for AO-10 dye and 93.55% for CR
dye. The results suggested that the CeO2 nanopowder could be potentially used
as an efficient adsorbent for the removal of synthetic organic dyes in
aqueous solution and may address for future concern in the area.
Simon Blackburn's projectivism and quasi-realism
Authors: Jovanovic Monika
Published: April 2014

In this paper, I will deal with Simon Blackburn?s metaethical theory.
Blackburn?s metaethics can be described by two ?-isms? - projectivism and
quasi-realism. In the first part of the paper, I will try to show what the
nature of their relation is. In the second part of the paper, I will discuss
two reasons Blackburn advances in favor of his projectivism. The first
pertains to the simplicity of his position, whereas the second claims that
projectivism, unlike cognitivism, can explain the thesis of supervenience of
moral features over the natural features. I will try to show that the first
argument does not have the strength, and that the second argument does not
have the plausibility that Blackburn ascribes to the two. In the third part
of the paper, I will point out to probably the hardest problem that every
non-cognitivist theory is faced with - the Frege-Geach problem. I will
discuss Blackburn?s attempt at a solution, and after that, express some
doubts with respect to the proposal that Blackburn puts forward.
When do the symptoms of autonomic nervous system malfunction appear in patients with Parkinson’s disease?
Authors: De Luka , Svetel Marina , Pekmezovic Tatjana , Milovanovic Branislav , Kostic Vladimir
Published: April 2014

Background/Aim. Dysautonomia appears in almost all patients with Parkinson?s
disease (PD) in a certain stage of their condition. The aim of our study was
to detect the development and type of autonomic disorders, find out the
factors affecting their manifestation by analyzing the potential association
with demographic variables related to clinical presentation, as well as the
symptoms of the disease in a PD patient cohort. Methods. The patients with PD
treated at the Clinic of Neurology in Belgrade during a 2-year period,
divided into 3 groups were studied: 25 de novo patients, 25 patients already
treated and had no long-term levodopa therapy-related complications and 22
patients treated with levodopa who manifested levodopa-induced motor
complications. Simultaneously, 35 healthy control subjects, matched by age
and sex, were also analyzed. Results. Autonomic nervous system malfunction
was defined by Ewing diagnostic criteria. The tests, indicators of
sympathetic and parasympathetic nervous systems, were significantly different
in the PD patients as compared with the controls, suggesting the failure of
both systems. However, it was shown, in the selected groups of patients, that
the malfunction of both systems was present in two treated groups of PD
patients, while de novo group manifested only sympathetic dysfunction. For
this reason, the complete autonomic neuropathy was diagnosed only in the
treated PD patients, while de novo patients were defined as those with the
isolated sympathetic dysfunction. The patients with the complete autonomic
neuropathy differed from the subjects without such neuropathy in higher
cumulative and motor unified Parkinson?s disease rating score (UPDRS) (p <
0.01), activities of daily living scores (p < 0.05), Schwab-England scale (p
< 0.001) and Hoehn-Yahr scale. There was no difference between the patients
in other clinical-demographic characteristics (sex, age at the time of
diagnosis, actual age, duration of disease, involved side of the body, pain
and freezing), but mini mental status (MMS) score and Hamilton depression and
anxiety rating scale were significantly lower (p < 0.05). Conclusion. Our
results confirm a high prevalence of autonomic nervous system disturbances
among PD patients from the near onset of disease, with a predominant
sympathetic nervous system involvement. The patients who developed complete
autonomic neuropathy (both sympathetic and parasympathetic) were individuals
with considerable level of functional failure, more severe clinical
presentation and the existing anxiety and depression.
Isolated hepatic sarcoidosis
Authors: Jovicic Ivana , Popovic Dusan , Toncev Ljubisa , Jovicic Zikica , Vucinic Violeta , Kovacevic Nada , Djuranovic Srdjan , Boricic Ivan , Micev Marjan , Spuran Milan , Milosavljevic Tomica
Published: April 2014

Introduction. Sarcoidosis is a multisystem granulomatous disease of unknown
etiology. Although hepatic granulomas occur in 50-65% of patients with
systemic sarcoidosis, isolated liver sarcoidosis is rare. Clinical
presentation varies from asymptomatic to manifest. The diagnosis is based on
a characteristic histopathological finding of liver biopsy. Case report. We
reported a 69-year old man was admitted due to abdominal swelling and
abdominal pain. Laboratory studies detected: cholestasis, pancytopenia and
elevaton of angiotensin-converting enzyme. Abdominal imaging techniques
showed liver cirrhosis, splenomegaly and ascites. The diagnosis of the
hepatic sarcoidosis was confirmed by histopathological examination of liver
biopsy. The patient was treated with corticosteroids. After 18 months the
patient was without any subjective symptoms, and with biochemical and
clinical improvement. Conclusion. Isolated hepatic sarcoidosis should be
considered in the differential diagnosis of asymptomatic or simptomatic
patients with hepatosplenomegaly and changes in liver functional tests. Only
the timely diagnosis and proper treatment can lead to subjective and
objective improvement of patients.
Price Shocks, News Disclosures, and Asymmetric Drifts
Authors: Lu Hai , Wang Kevin Q. , Wang Xiaolu
Published: April 2014

Motivated by investor disagreement and corporate disclosure literatures, we examine how stock price shocks affect future stock returns. We find that both large short-term price drops and hikes are followed by negative abnormal returns over the subsequent year, consistent with the conjecture that price shocks are useful indicators of intertemporal spikes in investor disagreement and investor opinion converges gradually. The asymmetric drifts involve return continuation for negative price shocks versus return reversal for positive price shocks, and are in sharp contrast to the general findings of symmetric drifts in corporate event studies. Moreover, price shocks associated with public news events are followed by significantly weaker downward drifts, suggesting that news disclosures mitigate disagreement-induced overpricing. Examining the dynamics of a disagreement proxy during and after price shocks, we provide further evidence for the disagreement hypothesis. The economic significance of the price shock effect is illustrated with a revised momentum strategy that generates an annualized abnormal return of 16.92 percent.
Shape Accuracy of Iron Precision Castings in Terms of Ceramic Moulds Physical Properties Anisotropy
Authors: Biernacki R. , Haratym R. , Tomasik J. , Kwapisz J.
Published: April 2014

While analyzing shape accuracy of ferroalloy precision castings in terms of ceramic moulds physical anisotropy, low-alloy steel castings ("cover") and cast iron ("plate") were included. The basic parameters in addition to the product linear shape accuracy are flatness deviations, especially due to the expanded flat surface which is cast plate. For mentioned castings surface micro-geometry analysis was also carried, favoring surface load capacity tp50 for Rmax = 50%. Surface load capacity tp50 obtained for the cast cover was compared with machined product, and casting plate surface was compared with wear part of the conveyor belt. The results were referred to anisotropy of ceramic moulds physical properties, which was evaluated by studying ceramic moulds samples in computer tomography equipment Metrotom 800
Evaluation of Casting Shrinkage and Liquid Metal Fluidity of IN-713C Alloy
Authors: Binczyk F. , Cieśla M. , Gradoń P. , Findziński R.
Published: April 2014

This paper presents the results of measurements of liquid metal fluidity and linear shrinkage of nickel alloy IN-713C in vacuum induction melting furnace Balzers VSG-2. Because of limited volume of the furnace chamber special models for technological trials were designed and constructed to fit in the mould of dimensions 170x95x100mm. Two different designs of test models were proposed: horizontal round rods and modified spiral. Preliminary studies were carried out for alloys Al-Si. Horizontal round rods test was useful for evaluation of fluidity of hypoeutectic silumin, however in case of nickel superalloy the mould cavity was completely filled in each test because of high required pouring temperature. Positive results were obtained from the modified spiral test for all alloys used in the research. Relationship between the linear shrinkage for the test rod and a specific indicator of contraction defined on a spiral was observed.
Some Mechanical Properties of Experimental Mg-Al -RE-Mn Magnesium Alloys
Authors: Braszczyńska-Malik K.N.
Published: April 2014

The results of some mechanical properties of four Mg-5Al-xRE-0.4Mn (x = 1 - 5) alloys are presented. The microstructure of experimental alloys consisted of an α-Mg phase and an α+γ semi-divorced eutectic, Al11RE3 phase and an Al10RE2Mn7 intermetallic compound. For gravity casting in metal mould alloys, Brinell hardness, impact strength, tensile and compression properties at ambient temperature were determined. The performed mechanical tests allowed the author to determine the proportional influence of the mass fraction of rare earth elements in the alloys on their tensile strength, yield strength, compression strength and Brinell hardness. The impact strength of the alloys slightly decreases with a rise in the rare earth elements mass fraction.
The Results of the Brass Refining Process in the Reducer Conditions
Authors: Bydałek A.W. , Bydałek A.
Published: April 2014

This article contains information concerning of the analysis the possibility of defining refinery qualities of the slag based thermo-physical and thermo-dynamical data. It was showed the brass refining with the many-carbide reagents introduced in to the slag. The paper presents the results of the structure analysis of the brass after carbide slag refining in the industrial conditions. The results of the macrostructure analysis have confirmed the argument on high reducing effectiveness of manganese and aluminium carbide used during CuZn39Pb2 alloy melting. The X-Ray microanalysis of the ingot cross-section has shown considerable discrepancies in the disposition of the inclusions. This effects showed on the great influence of reduction melting condition in to the brass melting.
Influence of Binding Rates on Strength Properties of Moulding Sands with the GEOPOL Binder
Authors: Holtzer M. , Drożyński D. , Bobrowski A. , Plaza W.
Published: April 2014

The results of investigations of moulding sands with an inorganic binder called GEOPOL, developed by the SAND TEAM Company are presented in the paper. Hardeners of various hardening rates are used for moulding sands with this binder. The main aim of investigations was determination of the influence of the hardening rate of moulding sands with the GEOPOL binder on technological properties of these sands (bending strength, tensile strength, permeability and grindability). In addition, the final strength of moulding sands of the selected compositions was determined by two methods: by splitting strength and shear strength measurements. No essential influence of the hardening rate on such parameters as: permeability, grindability and final strength was found. However, the sand in which the slowest hardener (SA 72) were used, after 1 hour of holding, had the tensile and bending strength practically zero. Thus, the time needed for taking to pieces the mould made of such moulding sand will be 1.5 - 2 hours.
Characteristics of Non-Ferrous Metal Alloys as Determined by Low-Cycle Fatigue Test under Variable Loads
Authors: Maj M. , Pietrzak K.
Published: April 2014

The paper presents the results of comparative tests of the fatigue properties conducted on two non-ferrous alloys designated as Al 6082 and Al 7075 which, due to the satisfactory functional characteristics, are widely used as engineering materials. The fatigue tests were carried out using a proprietary, modified low cycle test (MLCF). Particular attention was paid to the fatigue strength exponent b and fatigue ductility exponent c. Based on the tests carried out, the results comprised within the range defined by the literature were obtained. These results prove a satisfactory sensitivity of the method applied, its efficiency, the possibility of conducting tests in a fully economical way and above all the reliability of the obtained results of the measurements. Thus, the thesis has been justified that the modified low cycle fatigue test (MLCF) can be recommended as a tool used in the development of alloy characteristics within the range of low-cycle variable loads
The Formation of Gaseous Atmosphere in a Molten Cast Iron/Moulding Sand Contact System
Authors: Mocek J.
Published: April 2014

Drops of molten cast iron were placed on moulding sand substrates. The composition of the forming gaseous atmosphere was examined. It was found that as a result of the cast iron contact with water vapour released from the sand, a significant amount of hydrogen was evolved. In all the examined moulding sands, including sands without carbon, a large amount of CO was formed. The source of carbon monoxide was carbon present in cast iron. In the case of bentonite moulding sand with seacoal and sand bonded with furan resin, in the composition of the gases, the trace amounts of hydrocarbons, i.e. benzene, toluene, styrene and naphthalene (BTX), appeared. As the formed studies indicate much higher content of BTX at lower temperature it was concluded that the hydrocarbons are unstable in contact with molten iron.
Preliminary evaluation of the applicability of F, V and AEsignals in diagnosis of ADI machining process
Authors: Myszka D. , Bombiński S.
Published: April 2014

In this study, a preliminary evaluation was made of the applicability of the signals of the cutting forces, vibration and acoustic emission in diagnosis of the hardness and microstructure of ausferritic ductile iron and tool edge wear rate during its machining. Tests were performed on pearlitic-ferritic ductile iron and on three types of ausferritic ductile iron obtained by austempering at 400, 370 and 320°C for 180 minutes. Signals of the cutting forces (F), vibration (V) and acoustic emission (AE) were registered while milling each type of the cast iron with a milling cutter at different degrees of wear. Based on individual signals from all the sensors, numerous measures were determined such as e.g. the average or maximum signal value. It was found that different measures from all the sensors tested depended on the microstructure and hardness of the examined material, and on the tool condition. Knowing hardness of the material and the cutting tool edge condition, it is possible to determine the structure of the material .Simultaneous diagnosis of microstructure, hardness, and the tool condition is probably feasible, but it would require the application of a diagnostic strategy based on the integration of numerous measures, e.g. using neural networks.
Analysis of the Crystallization of AZ91 Alloy by Thermal and Derivative Analysis Method Intensively Cooled in Ceramic Shell
Authors: Rapiejko C. , Pisarek B. , Czekaj E. , Pacyniak T.
Published: April 2014

The work presents the test result of the influence of cooling rate on the microstructure of AZ91 alloy, Vickers micro-hardness and Brinell hardness. Studies cooling and crystallization of AZ91 alloy was cast into the ceramic shells preheated to 180 ° C and then air-cooled at ambient temperature or intensively super cooled in the liquid coolant. The TDA method was applied to record and characterize the thermal effect resulting from the phase transformations occurring during the crystallization of AZ91 alloy. The kinetics and dynamics of the thermal processes of crystallization of AZ91 alloy in the ceramic shells were determined. Metallographic tests were performed with the use of an optical microscope. A comparison of these test results with the thermal effect recorded by way of the TDA method was made. Influence of cooling rate of AZ91 on HV0, 01 micro-hardness and Brinell hardness alloy was examined
Effect of the Hold Time and Temperatureon Characteristic Quantities of TDACurves
Authors: Szymczak T. , Gumienny G. , Pacyniak T.
Published: April 2014

This paper presents the effect of the temperature and hold time in the holding furnace of 226 silumin on the characteristic quantities of TDA curves. The temperature of phase transformations and the cooling rate were tested.It has been shown that increasing both the hold time and the temperature in the holdingfurnace cause the decreasethe end ofα+Al9Fe3Si2+β and α+Al2Cu+βternary eutectics crystallizationtemperature in the tested silumin. This is due to the fact an increase in amounts of impurities as a result of reacting theliquid alloy with the gases contained in the air.It has been shown, however, that examined technological factors ofthe metal preparation do not cause systematic changes in the cooling rate.
Structural, Dielectric Specroscopy and Internal Friction Correlation in 2NB2O9 Ceramics
Authors: Adamczyk M. , Kozielski L. , Zachariasz R. , Pawełczyk M. , Szymczak L.
Published: April 2014

The research presented in this paper concerns BaBi2Nb2O9 (BBN) which is the member of the Aurivillius family and seems to be interesting from the point of view of its potential applications in storage media. Our investigations focused on temperature dependence crystal structure and mechanical properties of this ceramics as well as on the dielectric properties of samples. Correlation between positions of the maximum of the real part of electric permittivity and the behavior integral width of diffraction lines XRD versus temperature had been discussed based of the presence of polar nano-regions with orthorhombic distortion in macroscopic tetragonal matrix.
Effect of Surface Treatment on Corrosion Resistance of 304 Stainless Steel Implants in Tyrode Solution
Authors: Ahmadian Z. , Danaee I. , Golozar M.A.
Published: April 2014

The effect of different surface preparation methods such as mechanical, chemical and electrochemical surface preparation on the formation, stability and deterioration of surface films formed on austenitic 304 stainless steel was investigated in Tyrode’s physiological solution by cyclic polarization curves, AC impedance measurements surface techniques. A hysteresis loop in a cyclic polarization curve was obtained that indicates a delay in repassivation of an existing pit when the potential is scanned cathodically. Electrolytic polishing and ultrasonic cleaning improves corrosion resistance by increasing the value of the corrosion potential and breakdown potential of the passive layer as well as the pit initiation potential. After mechanical polishing no perfect passivation region was observed. Change in surface fractal is in good agreement with the result obtained from height roughness factor of AFM.
Microstructure and Properties of Cu-Nb Wire Composites
Authors: Głuchowski W.J. , Rdzawski Z.M. , Stobrawa J.P. , Marszowski K.J.
Published: April 2014

Nowadays, there is much activity all over the world in development of Cu-Nb composites for their potential use as conductors in high field magnets. This study was aimed at investigation of microstructure, mechanical and electrical properties of Cu-Nb composite wires. The investigated materials have been processed by vacuum furnace melting and casting, and then hot forging and cold drawing. Initial results of research into Cu-Nb composite material obtained using repeated iterative drawing of niobium wires compacted into copper tube, have been also presented in this article. The ultimate tensile strength versus cold deformation degree has been presented. These changes have been discussed in relation to microstructure evolution. It was assumed that repeated drawing of compacted wires is a promising method for fibrous composite production (more than 823,000 Nb fibres of nanometric diameter) characterized by high mechanical properties and electrical conductivity. Original SPD technique applied for Cu-Nb composite deformation result in initial microstructure refinement and improves effectiveness of wire production process.
Fabrication of Open Cell Fe-10%Al Foam by Space-Holder Technique
Authors: Golabgir M.H. , Ebrahimi-Kahrizsangi R. , Torabi O. , Saatchi A.
Published: April 2014

In this paper, fabrication of open-celled porous Fe-10%A1 foam by space-holder technique in which NaCl powder and polyester resin were utilized as space holder and binder respectively to generate 30-80% porosities was studied. FeAl solid solution was prepared via mechanical alloying method after 25 h high energy milling process. The results indicate that the size and shapes of the pores are determined by the size and shapes of NaCl particles. Also, when compaction pressure was in the range of 70-150 MPa and the sintering process was performed at temperature around 1100°C, the samples had the best quality. Microstructure observations show the pore size was in the range of 200-500 μm.
High-coercivity Nd-Fe-B Powders Obtained by High-Temperature Milling
Authors: Kaszuwara W. , Michalski B. , Orlowski P.
Published: April 2014

The possibility of employing high temperature milling (600°C) for the production of highly coercive Nd-Fe-B powders was examined. The materials were the Nd12Fe82B6, alloy which was subjected to mechanical milling and the powders of the constituent elements of this alloy which were processed by mechanical alloying. The processes were conducted in the two variants: the first variant consisted of mechanical milling performed at a high temperature which was maintained during the entire process, and the other variant included preliminary milling carried out at room temperature and then the milling temperature was increased. All the processes gave nanocrystalline powders with hard magnetic properties. The powders produced by mechanical milling had better properties than those produced by mechanical] alloying as they were more homogeneous and contained smaller amounts of the α-Fe phase.
Fabrication and Characterization of CU/B4C Surface Dispersion Strengthened Composite using Friction Stir Processing
Authors: Sathiskumar R. , Murugan N. , Dinaharan I. , Vijay S.J.
Published: April 2014

Friction stir processing has evolved as a novel method to fabricate surface metal matrix composites. The feasibility to make B4C particulate reinforced copper surface matrix composite is detailed in this paper. The B4C powders were compacted into a groove of width 0.5 mm and depth 5 mm on a 9.5 mm thick copper plate. A tool made of high carbon high chromium steel; oil hardened to 63 HRC, having cylindrical profile was used in this study. A single pass friction stir processing was carried out using a tool rotational speed of 1500 rpm, processing speed of 40 mm/min and axial force of 10 kN. A defect free interface between the matrix and the composite layer was achieved. The optical and scanning electron micrographs revealed a homogeneous distribution of B4C particles which were well bonded with the matrix. The hardness of the friction stir processed zone increased by 26% higher to that of the matrix material.
Synthesis and Characterization of New Refractory Coatings Based on Talc, Cordierite, Zircon and Mullite Fillers for Lost Foam Casting Process
Authors: Prstić A. , Aćimović-Pavlović Z. , Terzić A. , Pavlović L.
Published: April 2014

Refractory coatings based on different refractory fillers (talc, cordierite, zircon and mullite) for application in Lost Foam casting process were investigated. Design and optimization of the coatings composition with controlled, rheological properties included, and consequently synthesis were achieved by application of different coating components, namely different suspension agents and fillers and by alteration of the coating production procedure. Morphologic and microstructural analysis of fillers was carried out by means of scanning electronic microscope. X-ray diffraction analysis by means of X-ray diffractometer was applied in determination and monitoring the phase composition changes of the refractory fillers. An analysis of the particle size and shape was carried out by means of the PC software application package OZARIA 2.5. To assess the effects of application of individual refractory coatings, a detailed investigation of structural and mechanical properties of the moldings obtained was performed. Highlight was placed on revealing and analyzing surface and volume defects present on moldings. Radiographic molding tests were carried out by means of the X-ray device SAIFORT type-S200. Attained results are essential for the synthesis of refractory coatings based on high-temperature fillers and their applications in Lost Foam casting process for manufacturing of moldings with in-advance-set properties.
Fatigue Life Predictions of Metal Matrix Composites Using Artificial Neural Networks
Authors: Uygur I. , Cicek A. , Toklu E. , Kara R. , Saridemir S.
Published: April 2014

In this study, fatigue life predictions for the various metal matrix composites, R ratios, notch geometries, and different temperatures have been performed by using artificial neural networks (ANN) approach. Input parameters of the model comprise various materials (M), such as particle size and volume fraction of reinforcement, stress concentration factor (Kt), R ratio (R), peak stress (S), temperatures (T), whereas, output of the ANN model consist of number of failure cycles. ANN controller was trained with Levenberg-Marquardt (LM) learning algorithm. The tested actual data and predicted data were simulated by a computer program developed on MATLAB platform. It is shown that the model provides intimate fatigue life estimations compared with actual tested data.
Influence of Temperature of Accumulative Roll Bonding on the Microstructure and Mechanical Properties of AA5251 Aluminum Alloy
Authors: Bogucka J.
Published: April 2014

The influence of bonding temperature on microstructure and mechanical properties of AA5251 alloy sheets have been analyzed in the paper. The alloy was deformed with the method of accumulative roll bonding (ARB) in various temperature conditions i.e. at ambient temperature up to 5th cycle (ε = 4.0) and using pre-heating of sheet packs at 200°C and 300°C up to 10 cycles (ε = 8.0). The deformed material was subjected to structural observations using TEM, measurements of crystallographic texture with the technique of X-ray diffraction and tensile tests.

It was established that the temperature of roll-bonding had a significant effect on the structure evolution and the observed changes of mechanical properties. High refinement of microstructure and optimum mechanical properties were obtained for the material processed at lower temperatures, i.e. at ambient temperature and pre-heating at 200°C. Recovery structure processes occurring during deformation were observed in the alloy bonded with pre-heating at 300°C and therefore mechanical properties were lower than for the alloy bonded at lower temperatures.
The Portevin –Le Chatelier Effect and Acoustic Emission of Plastic Deformation CuZn30 Monocrystals
Authors: Ozgowicz W. , Grzegorczyk B. , Pawełek A. , Piatkowski A. , Ranachowski Z.
Published: April 2014

The paper presents the investigation of the relation between the acoustic emission (AE) and instability of plastic deformation type Portevin-Le Chatelier (PLC) of single-phase brass CuZn30 monocrystals with crystallographical orientation [1¯3 9]. The monocrystals have been investigated applying the method of free compression at a constant strain rate and the temperature within the range from 200°C to 400°C, simultaneously recording PLC phenomenon by means of acoustic emission. During hot axial compression tests the correlation between work-hardening curves σ - ε, which display PLC effect and characteristic of acoustic emission signals has been found. Moreover, it was proved that in the range of the PLC effect, the acoustic signal is an impulse a character of cyclic repeatability, distinctly correlated qualitatively with the stress oscillations on the curves σ - ε. The analysis of the obtained results leads to the conclusion that in the tested monocrystals the effect PLC is probably controlled by complex processes similar to the phenomenon of dynamic strain ageing (DSA), which are described by diffusion models.
Ball-milled Fe-Ni and Fe-Mn Matrix Powders For Sintered Diamond Tools
Authors: Romanski A. , Konstanty J.
Published: April 2014

The work presents the possibility of substitution of expensive, Co-WC powders, that have been traditionally used in the production of sintered diamond tools, with cheap iron-base counterparts manufactured by ball milling. It has been shown that ball-milled Fe-Ni and Fe-Mn powders can be consolidated to a virtually pore-free condition by hot pressing at 900°C. The as-consolidated materials are characterised by high hardness, bending strength and resistance to 3-body abrasion.
D-gun Sprayed Fe-Al Single Particle Solidification
Authors: Wołczyński W. , Senderowski C. , Morgiel J. , Garzeł G.
Published: April 2014

Some Fe-Al particles less than 50 μm in diameter were deposited onto the steel substrate by means of the D-gun spraying. A solidification mechanism of an individual particle is described. The particle subjected to the description contained nominally 63 at.% Al. The description was preceded by the TEM / SAED analysis of both the Fe-Al coating and Ni-20Cr interlayer. The whole number of the analyzed particles was partially melted during the deposition. The solidification products like: amorphous phase sub-layer, oscillatory sub-layer which contains two types lamellae distributed alternately and typically non-equilibrium phase sub-layer were revealed. In the micro scale, solidification was considered as a process which occurred in two directions: towards the substrate and towards the non-melted particle part. Both solidification processes underwent the positive thermal gradients. The boron addition was localized within the eutectic precipitates pushed and then rejected by the solid/liquid interface of the solidifying non-equilibrium phase. The proposed model is a general one and therefore can be applied to other systems ;description.
Influence of Bismuth Content on Complex Immittance Characteristics of Pressureless Sintered BiNbO4 Ceramics
Authors: Czekaj D. , Lisinńska-Czekaj A. , Adamczyk M.
Published: April 2014

Goal of the present research was to study immittance properties of BiNbO4 ceramics fabricated by the solid state reaction route followed by pressureless sintering. Four sets of samples were examined, namely the one fabricated from the stoichiometric mixture of oxides, viz. Bi2O3 and Nb2O5 as well as the ones with an excess of 3%, 5% and 10% by mole of Bi2O3. The immittance properties were studied by impedance spectroscopy. Measurements were carried out within the frequency range ν =20Hz-1MHz and temperature range T =RT-550°C. The Kramers-Kronig data validation test was employed in the impedance data analysis. It was found that complex impedance first increases with an increase in Bi2O3 content and decreases for 10mol% excess of Bi2O3. Two relaxation phenomena manifested themselves at elevated temperature (T>267°C) within the measuring frequency range. The conductivity relaxation phenomenon (M″(ν) spectra) took place at higher frequency than the phenomenon with dominant resistive component (Z″(ν) spectra).
Iron and Bronze Powdered Based Materials for Bearings with Surface Modified with Solid Lubricant Nanoparticles
Authors: Lijewski M. , Leshynsky V. , Wisniewska-Weinert H. , Sulej-Chojnacka J. , Rybak T.
Published: April 2014

In the recent years, a growth of demand for various types of self-lubricating elements of machines has been observed. A lot of parts are manufactured with the use of a powder metallurgy method. The Metal Forming Institute (INOP) in Poznan developed a modern technology, designed and made a tool for compaction of powdered parts with complex shapes and high density. The technology is being realised with a large scale equipment, which performs the forging and sizing of the sintered performs.

The present work describes development of manufacturing technology and determination of mechanical and tribological properties of nanocomposites for self-lubricating bearings with a very low friction coefficient. It is envisaged to use particulate materials which consist of nano-and microparticles of solid lubricant.

The study conducted aims at definition of a relationship between the microstructure and tribological properties of materials modified with solid lubricant MoS2 nanoparticles dispersed in a technological oil. INOP’s technology of nanoparticles manufacturing by RCT method (Rolling Cleavage Technology) results in that top layer of the porous bearing is modified with the nanoparticles. These layers are characterised by a low friction coefficient and considerably longer period of use. It should be noted that the stainless steel and bronze powders materials used have a good corrosion resistance. Production of the sintered bearings will disseminate the market especially in automotive and aircraft industries.
Surface Tension of Cu – Bi Alloys And Wettability in a Liquid Alloy – Refractory Material – Gaseous Phase System
Authors: Oleksiak B. , Łabaj J. , Wieczorek J. , Blacha-Grzechnik A. , Burdzik R.
Published: April 2014

The study involved measurements of surface tension of liquid binary copper-bismuth alloys with respect to their chemical composition and temperature as well as investigations of the liquid alloy - refractory material - gaseous phase system wettability using usual refractory materials, i.e. aluminium oxide, magnesium oxide and graphite. The experiments were performed with the use of sessile drop method and a high-temperature microscope coupled with a camera and a computer was utilised.
Microstructure and Creep Resistance of Mg-Al-Ca-Sr Alloys
Authors: Rzychoń T. , Adamczyk-Cieślak B.
Published: April 2014

Microstructure and creep properties of cast Mg-Al-Ca-Sr alloys have been investigated. The microstructure was characterized using light microscopy, scanning and transmission electron microscopy. Phase identification was made by EBSD technique and by SAED analysis. The measurement of volume fraction of intermetallic phases was performed using quantitative metallography. Creep tests were performed at 180°C and at applied stress between 45 and 90 MPa. Microstructure of tested alloys composed of α-Mg grains and intermetallic compounds in the interdendritic regions. It was found that the addition of calcium and strontium improves creep resistance at 180°C.
Aluminium AlMg1SiCu Matrix Composite Materials Reinforced with Halloysite Particles
Authors: Dobrzański L.A. , Tomiczek B. , Pawlyta M. , Król M.
Published: April 2014

In this work selected results of investigations of the new AlMg1SiCu matrix composite materials reinforced with halloysite particles manufactured by powder metallurgy techniques including mechanical alloying and hot extrusion are present. The composite materials obtained as a result of mechanical synthesis and hot extrusion are characterized with the structure of evenly distributed, disperse reinforcing phase particles in fine-grain matrix of AlMg1SiCu alloy, facilitate the obtainment of higher values of strength properties, compared to the initial alloy. The nanostructural composite materials reinforced with halloysite nanotubes with 15 mass % share are characterized by almost twice as higher micro-hardness - compared to the matrix material.
Influence of the Zinc Sublayer Method Production and Heat Treatment on the Microhardness of the Composite Ni-Al2O3 Coating Deposited on the 5754 Aluminium Alloy
Authors: Karaś M. , Nowak M. , Opyrchał M. , Bigaj M. , Najder A.
Published: April 2014

In this study, the effect of zinc interlayer on the adhesion of nickel coatings reinforced with micrometric Al2O3 particles was examined. Nickel coating was applied by electroplating on EN AW - 5754 aluminium alloy using Watts bath at a concentration of 150 g/l of nickel sulphate with the addition of 50 g/l of Al2O3. The influence of zinc intermediate coating deposited in single, double and triple layers on the adhesion of nickel coating to aluminium substrate was also studied. The adhesion was measured by the thermal shock technique in accordance with PN-EN ISO 2819. The microhardness of nickel coating before and after heat treatment was additionally tested.

It was observed that the number of zinc interlayers applied does not significantly affect the adhesion of nickel which is determined by thermal shock. No defect that occurs after the test, such as delamination, blistering or peeling of the coating was registered. Microhardness of the nickel coatings depends on the heat treatment and the amount of zinc in the interlayer. For both single and double zinc interlayer, the microhardness of the nickel coating containing Al2O3 particles increased after heat treatment, but decreased when a triple zinc interlayer was applied.
Evaluation of the Effect of Selected Alloying Elements on the Mechanical and Electrical Aluminium Properties
Authors: Mamala A. , Sciężor W.
Published: April 2014

Modern industry expects aluminum products with new, unusual, and well-defined functional properties. Last years we are able to notice constant development of aluminium alloys. In food industry, power engineering, electrical engineering and building engineering, flat rolled products of 1XXX series aluminium alloys are used.8XXX series alloys registered in Aluminium Association during last 20 years may be used as an alternative. These alloys have very good thermal and electrical conductivity and perfect technological formability. Moreover, these materials are able to obtain by aluminium scrap recycling. Fundamental alloy additives of 8XXX series are Fe, Si, Mn, Mg, Cu and Zn. Aluminium alloying with these additives makes it possible to obtain materials with different mechanical ale electrical properties. In this paper, the analysis of alloy elements content (in 8XXX series) effect on chosen properties of material in as cast and after thermal treatment tempers has been presented.
Phytoplankton composition and physicochemical properties in Lake Swarzędzkie (midwestern Poland) during restoration: Preliminary results
Authors: Kozak Anna , Kowalczewska-Madura Katarzyna , Gołdyn Ryszard , Czart Anna
Published: April 2014

This paper presents the preliminary results of a study of the phytoplankton structure and dynamics and physicochemical properties of Lake Swarzędzkie in 2011. The subject of the study is a shallow, elongated, post-glacial lake located in western Poland. The surface area is 93.7 ha with a maximum depth of 7.2 m. Its poor water quality led to the implementation of chemical and biological restoration procedures in an attempt to improve it. The highest concentration of total nitrogen was 13.07 mg l-1 N. Secchi depth (SD) was low in the summer with a minimum value of 0.5 m in September. The most abundant group of phytoplankton were cyanobacteria, and the maximum value of chlorophyll a concentration was 278.0 μg l-1. The dominant species were Pseudanabaena limnetica and Aphanizomenon gracile. Cyanobacteria were the most abundant phytoplankton until November. Maximum diatom, cryptophyte, and chrysophyte density was noted in the spring, and the most abundant were Nitzschia acicularis, Cryptomonas marssonii, Rhodomonas lacustris, Erkenia subaequiciliata, and Dinobryon sociale. One-hundred and thirty-six phytoplankton taxa belonging to nine taxonomic groups were identified in Lake Swarzędzkie. The highest number of taxa was noted among chlorophytes (57 taxa), cyanobacteria (19), diatoms (16), and chrysophytes (12), while other taxonomic groups were represented by smaller number of taxa.
Slope stability analysis with geo 5 software for “Łaski” Landslide in Międzybrodzie Bialskie
Authors: Michalski Andrzej
Published: April 2014

Abstract. Numerical modeling is an important tool to estimate slope stability. This publication shows application of a GEO 5 - slope stability software to evaluate stability of the “Łaski” Landslide in Międzybrodzie Bialskie. The slide surfaces, which were indentified in drill cores, were used to compute factors of safety (FS). The data from inclinometric measurements were used to verify the numerical model of the landslide. Calculations were carried out for three scenarios: first with normal water level, second scenario with lowered water level of 5 m and 10 m and the third scenario without water with the worst courses of sliding surfaces. As the result for each scenario the factors of safety were estimated. It was found that despite of water lowering and stabilization of existed surfaces, there is a considerable risk of a new sliding surfaces occurrence.
An application of geoelectrical methods for contamination plume recognition in Urbanowice waste disposal
Authors: Mycka Mateusz , Mendecki Maciej Jan
Published: April 2014

The purpose of this work was to detect groundwater pollution and to identify the conditions of soil and groundwater near the Urbanowice landfill site using geoelectrical measurements. Presented measurements are preliminary results from tested site and are beginning of continuous monitoring. Contamination outflows detected by resistivity and IP technique show a good correlation with available hydrological data. Contamination plume were found in Eastern part of survey profil.
Metallophytes in biotopes polluted by waste dumps rich in Zn-Pb, Cd (Olkusz region) – review of previous and planned research
Authors: Rożek Dorota
Published: April 2014

The aim of that publication was the presentation of previous and planned research concerning selected vascular plants and soils near Olkusz (Southern Poland). The extremely high concentration of heavy metals in soils from that region was caused by the natural geochemical aureoles of dispersed metals (due to weathering of Zn-Pb-Fe ore sulphides) and mining and processing of shallowly occurring metalliferous deposits (containing Ag-Pb and Zn-Pb ores) since XII century. The condition of stress in metals, shortage of water and some plant nutrition led to formation of some adaptable vegetation features by plants growing in that region. Some species called metallophytes have been already detailed investigated. Moreover some geochemical and pedological research of soil have been already done. However the conditions of habitat of pioneering species such as Koeleria glauca and Corynephorus canescens are not still recognized.
Application of multivariate data analysis in the construction of predictive model for the chemical properties of coke
Authors: Sajdak Marcin , Smędowski Łukasz
Published: April 2014

The aim of this work was to develop a statistical model which can predict values describing chemical composition of cokes performed in industrial scale. This model was developed on the basis of data that were taken from the production system used in the one of Polish coking plant. Elaborated equation include quality parameters of initial coals that form coal blends as well as contribution of additions such as coke and petrochemical coke. These equations allow to predict chemical composition of coke, e.g. contributions of: sulphur, ash, phosphorus and chlorine within the coke. A model was elaborated with use of STATISTICA 10 program and it is based on factor and multiply regression analyses. These analyses were chosen from among few kinds of regression analyses. They allowed to develop prediction model with the required goodness of fit between calculated and actual values. Goodness of fit was elaborated with:

• residuals analyses,

• residues normality and predicted normality

• mean absolute error

• Pearson correlation confidence
Gamma-ray-based measurement of concentration distribution in pipe flow of settling slurry: vertical profiles and tomographic maps
Authors: Krupička Jan , Matoušek Václav
Published: April 2014

Principles of gamma-ray-based measurement are summarized and their application is demonstrated on an operation of the radiometric facility installed in the test loop for slurry flows at the Institute of Hydrodynamics. The facility is able to measure vertical profiles of chord-averaged concentrations and concentration maps in the pipe cross section. A methodology of measurement is proposed including detection and quantification of random and systematic errors. Experimental results are discussed in the light of the proposed methodology. Experimentally determined vertical profiles of concentration are presented for slurry flows of four different fractions of glass beads. The tomographic application of the radiometric device is demonstrated on a measured concentration map and a suitable image reconstruction method is tested. High reliability of measured concentration distributions is proved except for regions near the pipe wall. The radiometric method is shown to be a useful tool for measurement of concentration distribution in slurry flow through a pipe.
Three-dimensional flow of an Oldroyd-B fluid over a bidirectional stretching surface with prescribed surface temperature and prescribed surface heat flux
Authors: Hayat Tasawar , Shehzad Sabir Ali , Alsaedi Ahmed
Published: April 2014

This paper concentrates on the mathematical modelling for three-dimensional flow of an incompressible Oldroyd- B fluid over a bidirectional stretching surface. Mathematical formulation incorporates the effect of internal heat source/sink. Two cases of heat transfer namely the prescribed surface temperature (PST) and prescribed surface heat flux (PHF) are considered. Computations for the governing nonlinear flow are presented using homotopy analysis method. Comparison of the present analysis is shown with the previous limiting result. The obtained results are discussed by plots of interesting parameters for both PST and PHF cases. We examine that an increase in Prandtl number leads to a reduction in PST and PHF. It is noted that both PST and PHF are increased with an increase in source parameter. Further we have seen that the temperature is an increasing function of ratio parameter
Sergiusz Hessen (1887 – 1950) – as creative European educationalist with no homeland
Authors: Kucha Ryszard , Świderska Mariola
Published: April 2014

This article examines the life and scientific career of the prominent European educationalist and pedagogue Sergiusz Hessen. His pedagogical heritage is examined on the base of basic primary writing and archive sources prepared in different languages. We are trying to show the contribution of the Hessen`s activity in the research methodology of multicultural societies and education, his philosophy of education, teaching knowledge, as well as in the real process of university and school education.
ROBONAUT 2: MISSION, TECHNOLOGIES, PERSPECTIVES
Authors: Tzvetkova Galia V.
Published: April 2014

The paper focuses on key aspects of scientific and techno- logical solutions implemented in the joint project of NASA and General Motors, Robonaut 2, a humanoid robot designed to work in space as a real assistant to astronauts.