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  1. 44 Acta Physica Polonica A

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  1. 4 Szewczyk R.

  2. 3 Baykara S.

  3. 3 Jackiewicz D.

  4. 2 Avcu E.

  5. 2 Aydin M.

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1
Content available remote

Importance of Measurement Parameters for the Dental Implant Surface Characterization

100%
Gunay A., Sagbas B., Durakbasa M.
Acta Physica Polonica A
|
2014
|
vol. 125
|
issue 2
484-487
EN
Pure titanium and its alloys have been widely used in biomedical applications on account of their biological and mechanical properties. Although the mechanical properties of titanium provide acceptable responses under dynamic pressures, surface modifications are needed in order to improve osseointegration between bone-implant interfaces. There are many different surface modification techniques like sand blasting, acid etching, or coating with various materials. Surface characterization is as important as surface modification for dental implants. Although many researchers studied about measurement of surface characteristics of dental implants with similar techniques but with different measurement parameters, there is still no consensus about the optimal surface characteristics values of a successful dental implant. Among many other surface characteristics, surface roughness is one of the most important features for dental implants. In this study, the importance of surface roughness measurement of dental implants is discussed and the need of a standardized procedure for implant surface roughness measurement is emphasized. In our experimental study three different processed surfaces as sand blasted and hydrofluoric acid etched surfaces, sand blasted and nitric acid etched surfaces and blasted surfaces were investigated. Results are compared via each method and each processing technique. It is aimed to highlight the importance of a standardized method for measuring and describing surface characteristics. More definitive, standardized methods are needed to augment the rather existing varied combined measurement parameters which affect the results for the assessment of biomedical surfaces.
2
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Analysis of Residual Stress States Using Diffraction Methods

100%
Reimers W.
Acta Physica Polonica A
|
1999
|
vol. 96
|
issue 2
229-238
EN
The possibilities and limitations of residual stress analysis using diffraction methods are discussed. Examples for the analysis of stress gradients in the near surface zone are given. The use of neutron diffraction and of high energy synchrotron radiation for the analysis of bulk stresses is demonstrated. Future trends of experimental residual stress analysis are outlined.
3
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Investigation of Mechanical Properties of MIG-Brazed 304 Stainless Steel and EN 10292 Galvanized Steel Joints using Different Current Intensity

63%
Varol F.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 1
34-35
EN
In this study, 304 stainless steel and EN 10292 galvanized steel plates having 1 mm thickness were joined by copper-based S Cu 6100(CuAl8) wire in gas metal arc brazing technique. Argon was used as shielding gas and brazing operations were done with gas flow speed as 12 L/min. Brazing operations were done with seven different weld currents as 40, 45, 50, 55, 60, 65, and 70 A. Having accomplished the brazing operations, tensile strengths of joints were tested, and micro and macro-structures of joints were investigated in order to see the joinability of 304 stainless steel and EN 10292 steels using different current intensity by gas metal arc brazing technique.
4
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Preparation and Characterization of LaMoO_3, La_xSr_{y}V_{z}O_3 and La_{x}Sr_{y}Mo_{z}O_3 Perovskite Type Oxides by the Sol-Gel Citrate Method

63%
Figen H., Guldal N., Baykara S.
Acta Physica Polonica A
|
2014
|
vol. 125
|
issue 2
278-280
EN
In this study, LaMoO_3, La_{x}Sr_{y}V_{z}O_3 and La_{x}Sr_{y}Mo_{z}O_3 perovskites have been prepared by the sol-gel citrate method and calcined at 1000C for 5 h. Ammonium carbonate and citric acid were used as complexing agent and solvent. Phases of synthesized materials were characterized with X-ray diffraction. Morphological analysis and elemental composition of perovskites were determined by scanning electron microscope and energy dispersive spectroscopy. The surface analyses of the solids have been studied using the Brunauer-Emmett-Teller surface analyzer. The effects of substitution of x, y, and z on the physical properties of the synthesized perovskites were also investigated.
5
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Preparation and Characterization of Co-Mo/γ-Al_2O_3, Ni-Mo/γ-Al_2O_3 and (Co/Ni)-Mo/γ-Al_2O_3 Metal Oxides by Sol-Gel Process

63%
Figen H., Baykara S.
Acta Physica Polonica A
|
2012
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vol. 121
|
issue 1
224-226
EN
In this study, Co-Mo/γ-Al_2O_3, Ni-Mo/γ-Al_2O_3 and (Co/Ni)-Mo/γ-Al_2O_3 metal oxides have been prepared by the sol-gel process using citric acid and calcined at 800C for 5 h. Phases of synthesized materials were characterized with X-ray diffraction. Morphological analysis and elemental composition of oxides were determined by scanning electron microscope and energy dispersion spectroscopy. Surface analyses of the metal oxides have been studied using the Brunner-Emmett-Teller surface analyzer. Effects of substitution of cobalt and nickel together on the physical properties of the synthesized oxides were also investigated.
6
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Characterisation of Segregation by Dynamic Neutron Radiography

63%
Balaskó M., Sváb E.
Acta Physica Polonica A
|
1999
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vol. 96
|
issue 1
7-18
EN
Dynamic neutron radiography is an advanced non-destructive technique to visualise and analyse different types of segregation phenomena in technically important objects. Here we describe applications on calorimetric devices studied during operation. Segregation behaviour in the water separator and formation of clogging in the tube system of absorption-type refrigerator is studied. Separation of lubrication oil on the surface of the cooling agent in the evaporator puffer of compression-type cooling units, and inhomogeneous distribution of the working fluid in thermostats is discussed.
7
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Magnetovision Scanning System for Detection of Dangerous Objects

63%
Nowicki M., Szewczyk R.
Acta Physica Polonica A
|
2014
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vol. 126
|
issue 1
382-383
EN
This paper presents an application of magnetovision based measurements to develop a method for passive detection of dangerous ferromagnetic objects. Scanning system was designed and built to study the magnetic field vector distributions. The measurements of the Earth's field disturbances caused by ferromagnetic objects were carried out. The ability for passive detection of selected dangerous objects was demonstrated. Further data processing allowed for determining the (x,y) coordinates of the object relative to the plane of measurement, and even the possibility of calculating the distance from the object. The results obtained indicate that it is possible to detect and determine the location of dangerous ferromagnetic objects. This opens the new way to use magnetovision in public security systems, in particular for the detection of dangerous objects by police and sapper robots.
8
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Mechanical Properties of Soda-Lime-Silica Glasses with Variable Peanut Shell Contents

51%
Aktas B., Albaskara M., Yalcin S., Dogru K.
Acta Physica Polonica A
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2017
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vol. 131
|
issue 3
511-513
EN
In this study, the mechanical properties of soda-lime-silica glasses were investigated by using micro-Vickers indentation tests, while varying the amount of peanut shell powder added to the glass. Peanut shell powder was obtained by grinding peanut shells. It was added as a dopant to glass at 0.5-5 wt.%, with the final glass samples being produced by melting. Peanut shell addition had led to a decreased density of the soda-lime-silica glasses, and X-ray diffraction data of the peanut shell-doped soda-lime-silica glasses indicated the presence of two crystalline phases, namely, anorthite (Na_{0.45}(Ca_{0.55}Al_{1.55}Si_{2.45}O₈) and magnesium aluminum silicate (MgAl₂Si₃O_{10})₆. The Young's modulus values of the soda-lime-silica glasses increased along with the amount of peanut shell powder added. Peanut shell addition to the soda-lime-silica glasses has also caused increased hardness. Fracture toughness values of these glass samples were in the range of 0.91-1.04 MPa m^{1/2}. Thus, the mechanical properties (e.g. E and K_{C}) of soda-lime-silica glasses could be enhanced through peanut shell addition.
9
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Ageing Phenomena in La-Sr Manganites with Divalent Substituents for Manganese

51%
Merkulov D., Badelin A., Estemirova S., Karpasyuk V.
Acta Physica Polonica A
|
2018
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vol. 133
|
issue 3
529-531
EN
Variations of electromagnetic and structural characteristics of La_{1-c+x}Sr_{c-x}Mn_{1-x}Me_{x}O_{3+γ} manganites (Me = Zn, Ni) during storage time up to 36000 hours at room temperature and after frequentative thermal cycling in the 300-573 K range were investigated. Changes of magnetization of all samples were within the error of measurement. In most cases Curie point (T_{C}) showed irregular variations within the range of 20%, while zinc-substituted manganites with relatively high values of "c" exhibited some trend of T_{C} rise. The resistance of all samples increased during storage period. The cell volume of single-phase manganites decreased over time, that may indicates an increase in oxygen content. However, the sample with the highest Ni content (x=0.125) at c=0.19 suffered phase transition "rhombohedral-orthorhombic structures", which cannot be explained by the oxygen absorption. Probably, this effect was due to the rearrangement of the ions and vacancies between crystal sublattices of manganite.
10
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Wear Behavior of Surface Treated X45MoCrV5-3-1 Tool Steel at Room and Elevated Temperatures

51%
Aktaş G., Polat Ş., Atapek Ş.
Acta Physica Polonica A
|
2015
|
vol. 127
|
issue 4
1221-1224
EN
The aim of this study is to compare the wear behavior of X45MoCrV5-3-1 tool steel, used as die material in aluminum extrusion, after single treatment (CrN coating) and duplex treatment (nitriding and CrN coating). Gas nitriding and physical vapor deposition were used as processing techniques and wear tests were carried out at both room and elevated temperatures. A "ball-on-disc" type tribometer was used for room temperature tests, utilizing Al₂O₃ ball as counterpart. In order to simulate the wear conditions during extrusion, hot wear tests were carried out at 450°C using "block-on-cylinder" type tribometer against AA 6080 material. Worn surfaces were studied by microscopy to reveal the wear characteristics of treated steels. It was found that (i) duplex treated steel, having higher friction coefficient at room and elevated temperature, had higher wear resistance, (ii) at room temperature single treated steel exhibited higher volume loss than the duplex treated one, (iii) at elevated temperature duplex treated steel revealed a stable coating layer, whereas micro cracks were observed on the surface of the single treated steel.
11
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Application of Extended Jiles-Atherton Model for Modelling the Influence of Stresses on Magnetic Characteristics of the Construction Steel

51%
Jackiewicz D., Szewczyk R., Salach J., Bieńkowski A.
Acta Physica Polonica A
|
2014
|
vol. 126
|
issue 1
392-393
EN
Paper presents the possibility of application of the Jiles-Atherton extended model to describe the magnetic characteristics of construction steel C45 under the influence of tensile stresses. Experiment was performed on the frame-shaped samples. Then, the influence of stresses on hysteresis loops was modelled with the Jiles-Atherton extended model. The obtained results of the modelling are consistent with results of the experimental measurements. The results of modelling create new possibilities of explanation of the physical phenomena connected with magnetisation of the magnetic materials under stresses, which is esential for the assessment of the state of the construction steel during its exploitation in industrial conditions.
12
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Structural Characterization of Al_2O_3 and CeO_2 Supported Ni, Co Loaded Ceramic Monolithic Catalysts

51%
Guldal N., Baykara S.
Acta Physica Polonica A
|
2014
|
vol. 125
|
issue 2
281-284
EN
This paper discusses structural characterizations of monolithic catalysts prepared by incorporating Ni and Co supported over a porous alumina and ceria layer by using respective nitrates and H_2PtCl_6 as precursors. Monolithic catalysts were synthesized by dip-coating of 400 cpsi cordierite ceramic monolithic pieces cut in 20 × 13 mm^2 (L× D) into appropriate solutions of metals, followed by calcination in air at 800C for 4 h. Phases of catalysts were characterized with X-ray diffraction. Morphological analysis and elemental composition were determined by scanning electron microscope and energy dispersive spectroscopy. The specific surface area analysis have been studied using the Brunauer-Emmett-Teller method. Metal contents were determined by inductively coupled plasma optical emission spectrometry.
13
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Activation Energy in Hot Forming of Selected Fe-40at.%Al Type Intermetallic Compounds

51%
Schindler I., Kawulok R., Kulveitová H., Kratochvíl P., Šíma V., Knapiński M.
Acta Physica Polonica A
|
2012
|
vol. 122
|
issue 3
610-613
EN
Promising potential of the Fe-40at.%Al type alloys is used only in a limited way as yet, mainly due to their high brittleness. With regard to attraction of the given type material, the plastometric research at temperatures 800C to 1200C was carried out as a basic one, namely using the uniaxial compression tests at strain rates 10^{-2} s^{-1} to 10^1 s^{-1}. Cylindrical samples were manufactured from laboratory castings, gained by means of the vacuum induction furnace. Two materials were tested - Fe-40Al and Fe-40Al+TiB_2. From the measured flow stress curves the values of maximum stress were obtained and used for determination of the activation energy in hot forming according to the classical equation of the hyperbolic sine type. Enumeration of its parameters led to a possibility to predict maximum deformation resistance values of the investigated alloys in dependence on temperature and strain rate. Pronounced effect of the added titanium diboride particles (< 10 μm) on the activation energy value and to a resistance to the formation of cracks was observed. Thanks to the obtained value of activation energy an equation sufficiently describing the initiation of dynamic recrystallization process in the Fe-40Al+TiB_2 material as a function of the Zener-Hollomon parameter could be derived.
14
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Electron Microscopy of Cracks in In_{x}Ga_{1-x}As/GaAs(001) Multi-Quantum Wells

51%
Atici Y., Yildiz K., Akgul U.
Acta Physica Polonica A
|
2015
|
vol. 127
|
issue 3
859-862
EN
We studied cracks in two different In_{x}Ga_{1-x}As/GaAs(001) multi-quantum-well structures by electron microscopy. Transmission and scanning electron microscopy analyses of the sample-1 revealed that the epilayers associated with cracks. Detailed experimental works on the cracks were carried out by conventional and high-resolution electron microscopy. It was found that the epilayers were very effective on stopping the cracks in sample-1. Many dislocations were observed around the cracks and cracks tips. SEM images showed that the cracks formed an orthogonal set array accompanying with slits and pits. However, there were not observed any cracks in the sample-2.
15
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Mean Grain Size and Pore Effects οn Ultrasonic Properties οf WC-Fe-Ni and SiC-Fe-Ni Composites

51%
Sarpün İ., Özkan V., Yönetken A., Erol A.
Acta Physica Polonica A
|
2013
|
vol. 123
|
issue 4
688-694
EN
In this work, electroless nickel plating technique was used with WC-Fe and SiC-Fe powders. Plated powders were sintered at temperature ranging from 600C to 1100C under argon shroud in Phoenix microwave furnace. The mean grain size is determined by using three different techniques namely ultrasonic velocity, ultrasonic attenuation, and rate of screen heights of successive peaks according to the pulse-echo method by using a 2 MHz and a 4 MHz probes compared with the scanning electron microscopy images. In addition, the relative effects of porosity on ultrasonic attenuation and velocity in the WC-Fe-Ni and SiC-Fe-Ni composite samples are studied. It is seen that the ultrasonic velocity, the ultrasonic attenuation, the rate of screen heights of successive peaks have a linear relation with the mean grain size of samples. However, the correlation coefficients of porosity graphs have higher values than mean grain size graphs for the composite materials as expected. This indicates that porosity determines the ultrasonic velocity and attenuation for the composite samples.
16
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Examining with the Sintered Temperature of Mean Grain Size of B_4C-Al-Ni Composites by Ultrasonic Techniques

51%
Özkan V., Sarpün İ.
Acta Physica Polonica A
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2012
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vol. 121
|
issue 1
184-186
EN
Hard, tough, lightweight boron-carbide-reactive metal composites, boron-carbide-aluminum composites, are produced. The ultrasonic velocity and attenuation were measured on B_4C-Al-Ni ceramic-metal composites, which are sintered in the temperature range 500-1200°C, by using the pulse echo method. Ultrasonic velocity, ultrasonic attenuation and rate of screen heights of successive peaks were determined according to the pulse-echo method by using 2 MHz and 4 MHz probes. It was observed that the mean grain size of samples has been changed with the sintering temperature. The velocity was found to be pretty sample dependent at room temperature and increased with increasing sintering temperature. The ultrasonic attenuation at room temperature was found to be more sample dependent. The sintering temperature variation of ultrasonic attenuation exhibited broad minimum values around 1200C and sharp maximum values at 500°C. The increase observed in the temperature variation of longitudinal velocities and attenuation has been qualitatively explained with the help of the temperature variation of decrease value.
17
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Investigation of the Effect of Different Current Loads on the Arc-Erosion Performance of Electrical Contacts

51%
Biyik S., Aydin M.
Acta Physica Polonica A
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2016
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vol. 129
|
issue 4
656-660
EN
In this study, arc-erosion experiments using contactors were performed under inductive loads for up to 40000 switching operations to investigate the effect of different current loads on the arc-erosion performance of electrical contacts. Determination of the mass loss was performed after every 5000 operations. The arc-eroded surfaces were examined using scanning electron microscopy. The chemical composition near the arc was determined by energy dispersive X-ray spectroscopy. The results show that the contact surfaces are greatly affected by arc-erosion, resulting in mass loss due to material migration and/or evaporation. In addition, the arc-affected zones become bigger with the increase in the number of switching operations, especially at 20 A. However, electrical cleaning improves the contact performance by reducing the contact resistance due to breakdown of the non-conducting oxide films formed between 20000 and 25000 switching operations at 20 A. The stationary contacts experience major erosion, whereas the movable contacts suffered less contact erosion under each current load.
18
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Fabrication and Arc-Erosion Behavior of Ag8SnO₂ Electrical Contact Materials under Inductive Loads

51%
Biyik S., Aydin M.
Acta Physica Polonica A
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2017
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vol. 131
|
issue 3
339-342
EN
In this study, Ag-based SnO₂-reinforced electrical contact materials were produced by powder metallurgy and mechanical alloying techniques. Elemental powder mixture containing 8 wt.% SnO₂ was milled in a high-energy planetary-type ball mill, to achieve homogeneously mixed composite powder, and subsequently pressed in a closed die to obtain green compacts with a cylindrical shape and then sintered under vacuum to obtain composites. Composites were then subjected to electrical wear tests under inductive loads to investigate the arc-erosion performance of electrical contacts. Surface deterioration and mass losses of electrical contacts were also evaluated, as a function of increasing switching number. Characterization of the starting and composite powders, green compacts, composites and arc-originated surface deterioration was carried out using scanning electron microscopy and energy-dispersive X-ray spectroscopy. It was found that powder particle size had decreased with the increasing milling time. Density and hardness values of the composites had increased, whereas porosity had decreased with the increasing sintering temperature. Optimum sintering temperature was determined as 900°C. The arc-affected zones became bigger with the increase of the number of switching operations. Furthermore, comparison between surface morphologies and mass losses of arc-eroded specimens had revealed that the stationary contacts exhibit higher rates of erosion than the movable contacts.
19
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Intermittency and Deformation Band Propagation in an Austenitic FeMnC TWIP Steel

51%
Lebyodkin M., Lebedkina T., Roth A., Allain S.
Acta Physica Polonica A
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2012
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vol. 122
|
issue 3
478-481
EN
Plastic deformation of austenitic FeMnC TWIP steels exhibits complex spatiotemporal patterns associated with the occurrence of deformation bands and the concomitant fluctuations of the deforming stress. Although the plastic instability is a generic property of these steels and is usually attributed to interaction of dislocations with solutes (the Portevin-Le Chatelier effect), both the kinematics of the deformation bands and the characteristic shape of stress serrations observed in the carbon-containing TWIP steel at room temperature manifest unusual features. The nature of these peculiarities and the mechanism of jerky flow in such steels are unclear. In the present work, an attempt is made to get an insight into the jerky flow in the Fe22Mn0.6C steel by studying the time series characterizing the evolution of plastic deformation at various scales: stress-time curves, local strain field, and acoustic emission accompanying the deformation processes. Stress and strain fluctuations related to two distinct scale ranges are detected and characterized.
20
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Effect of Gravitation on Water Migration in Granular Media

51%
Milczarek J., Fijał-Kirejczyk I., Żołądek J., Chojnowski M., Kowalczyk G.
Acta Physica Polonica A
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2008
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vol. 113
|
issue 4
1245-1254
EN
The results of the experiments on water migration in unsaturated granular media performed with dynamic neutron radiography technique are presented. It was found that the porosity of the medium did not determine the kinetics of the process in a marked way. The influence of gravity was found to be considerable for media like coarse sand and gravel, consisting of large grains. No effect of gravitation on the water migration in clay beds was observed. The results are discussed in terms of the classical Washburn-Bosanquet theory of adhesion driven motion of the liquid in a straight circular capillary under gravity. It was found that this theory provides only qualitative description of the water migration within granular media, and the viscous dissipation effects are greatly underestimated.
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