|Gholamreza Nabiyouni - Giant magnetoresiscance in spintronic Co/Pt
|T. Ekino, A. M. Gabovich, M. S. Li, M. Pękała,
H. Szymczak, A. I. Voitenko - Charge-density-wav features in tunnel spectra of high-T
|Ireneusz Jabłoński, Janusz Mroczka - Frequency indexes of respiration during interrupter experiment||153|
|Aleksander Olczyk - Specific mass flow rate measurements in a
pulsating flow of gas||165|
|Tomasz Barszcz - Proposal of architecture of distributed vibration monitoring system with flexible architecture and remote access support||177|
|Grzegorz Jasiński, Piotr Jasiński, Bogdan Chachulski - Nano-porous alumina humidity sensors||195|
|Paweł Wierzba - Stability of an optical displacement sensor using a two-beam polarization interferometer||205|
|R. Uklejewski, M. Winiecki, J. Mielniczuk, P. Rogala,
A. Augu¶ciński - The poroaccessibility parameters for three-dimensional
characterization of orthopaedic implants porous coatings||215|
|Leszek Lipiński, Anna Szmyrka-Grzebyk - Proposals for the new definition of the kelvin||227|
|Janusz Mroczka - Tenth anniversary of Chair of Electronic and Photonic Metrology Wrocław University of Technology||237|
|Tomasz R. Woliński, Ryszard S. Romaniuk - Photonics Society of Poland established||241|
ABSTRACTS & FULL PAPERS
University of Arak
Department of Physics, Iran
GIANT MAGNETORESISCANCE IN SPINTRONIC CO/PT
We used electrodeposition for growing of pure metallic, alloy and multilayer nanowires. Electrodeposition of cobalt/platinum nanowires was achieved in the cylindrical pores of a commercially available nuclear tracked polycarbonate membrane. In order to make an ohmic contact, prior to electrodeposition one side (the back one) of the membranes was coated with gold, using a simple evaporation technique. An assembly of nanowires with an average diameter of 80 nm and a length of 6 microns was achieved. Our multilayer nanowires were grown from an electrolyte containing Co2+ and Pt2+ ions.
The samples were then characterized using scanning and transmission electron microscopy. The selected area diffraction patterns of the wires showed that the growth is polycrystalline, though the measured grain size was relatively large . Magnetic properties of the nanowires were studied using vibrating sample magnetometry (VSM). Resistivity of the Co/Pt multilayer nanowires then was measured as a function of applied magnetic field in both parallel and perpendicular to the nanowire growth directions. The samples clearly exhibit a giant magnetoresistance (GMR) effect which can be explained in terms of spin-dependent scattering phenomena. The results are of particular interest since they promise potential devices for nano-magnetic sensors, especially devices based on spintronic materials [2, 3, 4].
T. EKINO1, A. M. GABOVICH2, M. S. LI3, M. PĘKAŁA4,
H. SZYMCZAK3, A. I. VOITENKO2
Faculty of Integrated Arts and Sciences, Higashi-Hiroshima, Japan
2Institute of Physics, Kyiv, Ukraine
3Institute of Physics, Warsaw, Poland
4University of Warsaw
Department of Chemistry, Warsaw, Poland
CHARGE-DENSITY-WAV FEATURES IN TUNNEL SPECTRA OF HIGH-T
Tunnel conductance G(V) was calculated for junctions between a normal metal and a spatially inhomogeneous superconductor with a dielectric gap on the nested sections of the Fermi surface or between two such superconductors. The dielectric gapping was considered to be a consequence of the charge density wave (CDW) appearance. Spatial averaging was carried out over domains with randomly varying parameters of the CDW superconductor (CDWS). The calculated G(V)s demonstrate a smooth transformation from patterns with a pronounced dip-hump structure (DHS) at low temperature, T, into those with a pseudogap depletion of the electron density of states at higher T within the range of actual critical temperatures of the CDWS domains. Thus, it is shown that both the DHS and the pseudogap have the same origin. This circumstance provides a new insight into the problem and explains the peculiar features of G(V) for Bi2Sr2CaCu2O8+δ and related high-Tc cuprates. At the same time, the approach, being quite general, can be applied to other CDWSs which belong to various other classes of materials.
Keywords: superconductivity, pseudogap, charge-density wave, non-homogeneity, tunneling, diphump structure
IRENEUSZ JABŁOŃSKI, JANUSZ MROCZKA
Wroclaw University of Technology
Chair of Electronic and Photonic Metrology
Poland, e-mail: firstname.lastname@example.org
FREQUENCY INDEXES OF RESPIRATION DURING INTERRUPTER EXPERIMENT
A new issue of the respiratory mechanics evaluation by the frequency mode of the interrupter technique is undertaken in the paper. The aim of the computer-aided research is to show the abilities to separate airways and tissue properties of the respiratory system. The proposed evaluation procedure of the identification quality in the modified DuBois model proves the possibility to conduct repeatable measurements of the important diagnostic indexes. The obtained precision of the parametric description of the investigated physiological system suggests the need to continue the work in the outlined direction. Their final effect can be a portable device with applicability to clinically diffcult subjects - infants and pre-school children.
Keywords: respiratory mechanics; interrupter technique; frequency-domain identification
Technical University of Lodz
Institute of Turbomachinery, Poland
SPECIFIC MASS FLOW RATE MEASUREMENTS IN A
PULSATING FLOW OF GAS
The method of measurement of the specific mass flow rate in a pulsating flow by means of the Constant Temperature Anemometer (CTA) has been described. Special attention has been paid to the probe calibration problem. Different forms of the CTA characteristic have been analyzed. Example measurement results have been presented for chosen pulse frequencies. Apart from the measurements executed in one single point representing each control section, a flow field survey has been done in order to determine the velocity profile under the conditions of a pulsating flow. Probes have been displaced radially with a small step to cover the range from the pipe axis to its wall. It has been found that in the large field around the pipe axis, successive velocity plots are similar as far as their shape and phase shift are considered. Pulsations are damped and mean velocity decreases rapidly only in direct proximity of the pipe wall. It has been also shown that the presence of pulsations makes the mean velocity profile more uniform than in the case of a steady flow. Measurements have been also performed for the case of a reverse flow occurring in the pipe at resonance frequencies.
Keywords: pulsating flow, hot wire probe, calibration, approximation, flow field survey
AGH University of Science and Technology
Department of Robotics and Mechatronics
PROPOSAL OF ARCHITECTURE OF DISTRIBUTED VIBRATION MONITORING SYSTEM WITH FLEXIBLE ARCHITECTURE AND REMOTE ACCESS SUPPORT
With advances in IT technologies even complex machines with several gears and bearings, running at varying rotational speed can be effciently monitored with an algorithm consisting of a combination of signal envelope and synchronous resampling.
For implementation, robust advanced software development technologies are applied, based on an object-oriented approach, supported by formal methodologies, like UML. Another concept important for distributed systems is middleware, like RPC or DCOM.
The paper presents a proposal of the architecture of the distributed vibration monitoring and diagnostic system, based on the approaches mentioned above. Principal components are described and their functionality is discussed. Special interest was put on flexibility of architecture and optimization of remote access. XML was proposed as universal and effcient means of configuration storage. The structure of the monitored machine should also be stored in XML. A proposal of such a data structure is described for a gas compressor.
Another key component is the database server. It needs to handle multiple databases and multiple users, delivering fast and reliable data. Vibration signal handling can be more effcient when signals are processed on the server side. Effciency is essential when remote access to vibration data is required and data link is limited. Such a mechanism, based on plug-in approach, is proposed and described.
Finally, the paper presents a case study which describes the installation of the system on a gas compressor. The measured data are presented after different processing algorithms. High resolution envelope order spectrum was able to detect the bearing failure.
Keywords: distributed system, vibration monitoring, configuration, database
GRZEGORZ JASIŃSKI1, PIOTR JASIŃSKI1, BOGDAN CHACHULSKI2
Gdansk University of Technology
1Faculty of Electronics Telecommunications and Informatics, Poland
e-mail: email@example.com, firstname.lastname@example.org
2Chemical Faculty, Poland
NANO-POROUS ALUMINA HUMIDITY SENSORS
In this paper the details of porous alumina humidity sensors fabricated using anodic aluminium oxidation are presented. The main aim of this study is to establish relations between technological process parameters and electrical properties of sensors. Surface morphology was investigated by scanning electron microscopy. Impedance spectroscopy was used to identify electrical parameters of the sensor.
Keywords: ceramic humidity sensors, alumina film, impedance spectroscopy
Gdańsk University of Technology
Faculty of Electronics, Telecommunication and Informatics
Department of Optoelectronics and Electronic Systems, Poland
STABILITY OF AN OPTICAL DISPLACEMENT SENSOR USING A TWO-BEAM
Optical interferometers can measure displacement with a resolution of tens of picometers. Polarization interferometers are often used in such measurements, as they exhibit much lower sensitivity to most of the perturbations. Although properties of these interferometers designed for metrology applications are fairly well documented, little is known about the stability of such interferometers in typical laboratory settings, where they work without vibration isolation setups or controlled flow of air. In order to assess the stability of such interferometers, a representative two-beam polarization interferometer was built on an optical plate using off-the-shelf components. Based on the results of performed measurements it is possible to conclude that such interferometers can be used for measurements when a drift of the order of ten nanometers during a 30 s interval is acceptable.
Keywords: polarization interferometry, two-beam interferometer, displacement measurement, stability of interferometers
R. UKLEJEWSKI1, M. WINIECKI1, J. MIELNICZUK2, P. ROGALA3, A. AUGU¦CIŃSKI2
1Kazimierz Wielki University
Department of Fundamentals of Medical Bioengineering
Institute of Technology, Bydgoszcz, Poland
e-mails: email@example.com, firstname.lastname@example.org
2Poznan University of Technology
Chair of Machine Design Fundamentals, Poland
e-mails: email@example.com, firstname.lastname@example.org
3Poznan University of Medical Sciences
Department of Spine Surgery, Orthopaedics and Traumatology, Poland
THE POROACCESSIBILITY PARAMETERS FOR THREE-DIMENSIONAL
CHARACTERIZATION OF ORTHOPAEDIC IMPLANTS POROUS COATINGS*
The ability of formation of the proper bone-porous implant fixation depends, among others, on the structural-osteoinductive properties of the porous coating covering the orthopaedic implant surface. These properties, describing the poroaccessibility of porous biomaterial, are one of co-factors conditioning the promotion of bone tissue ingrowth into pore space of implant porous coating. So far the structural-osteoinductive properties of implants porous coatings are described by the traditional two-dimensional roughness parameters obtained with contact or non-contact roughness profile measurement (mostly standard surface roughness amplitude parameters e.g.: Ra, Rq, Rmax) or with the average pore size, which is, in the authors opinion, inadequate and unsatisfactory for porous coating characterization in respect of its poroaccessibility. The lack of proper directives on porous structure characterization of titanium and hydroxyapatite coatings on orthopaedic implants is the reason to work them out. In connection with the development of methods for surface texture analysis in three dimensions, the authors have perceived new possibilities for porous coatings microstructure analysis and on this base a set of parameters of poroaccessibility of implant porous coating for bone tissue ingrowth has been proposed: the effective volumetric porosity ΦVef , the index of the porous coating space capacity VPM, the representative surface porosity ΦSrep, the representative pore size pSrep, the representative angle of the poroaccessibility Ωrep and the bone-implant interface adhesive surface enlargement index Ψ. With this set of parameters one can characterize the structural-osteoinductive properties of porous biomaterial. In this paper a new set of poroaccessibility parameters of implant porous coatings and a method of calculation of these parameters on the basis of three-dimensional roughness measurements are presented.
Keywords: Surface topography, joint replacement, biologic fixation of implants, bone tissue ingrowth, porous coating poroaccessibility
* This work was financed by research project no 4 T0/C 056 29.
LESZEK LIPIŃSKI, ANNA SZMYRKA-GRZEBYK
Institute of Low Temperature and Structure Research
Polish Academy of Sciences, Wrocław
e-mail: A. Szmyrka@int.pan.wroc.pl
PROPOSALS FOR THE NEW DEFINITION OF THE KELVIN
The International Committee forWeights and Measures (CIPM) has had a long-term aim of defining all of the base units in the terms of fundamental physical constants to eliminate any artifact on material dependencies. In 2005, in Recommendation 1, the CIPM approved preparative steps towards new definitions of the kilogram, the ampere, the Kelvin and the mole in terms of fundamental constants [1, 2].
The unit of temperature, the Kelvin, can be defined in terms of the SI unit of energy, the joule, by fixing the value of the Boltzmann constant k which is simply the proportionality constant between temperature T and thermal energy kT . The new definition would be in line with modern science where nature is characterized by statistical thermodynamics, which implies the equivalence of energy and temperature as expressed by the Maxwell-Boltzmann equation. The Boltzmann constant k is not connected with the other fundamental constants, there are no alternatives to the linking of the Kelvin aside from the exact value of the constant k.
In practice, no universal instrument for measuring energy exists while energy appears in different forms, e.g. temperature. Currently, several experiments are underway to determine k using primary thermometers of different types [3, 4].
From the point of view of practical thermometry it is necessary to determine what uncertainty in the measured value of k is needed to apply it as the temperature unit. It would be of the order in the present realization of the triple point of water: = 1.8×10-7. At present its uncertainty is about one order of magnitude higher.