Temat: 07.20.-n - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Design of a Laboratory Unit Air-Conditioning System with Matlab/Simulink Software
Autorzy:: Koçyiğit, N.
Şahin, M.
Tematy:: 07.05.Tp
07.20.-n
07.20.Mc; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1031881.pdf Link otwiera się w nowym oknie
Opis:: In this study, design of an electronic air-conditioning system was carried out using Matlab/Simulink software. The air-conditioning system was designed as a laboratory experimental setup. The aim of this study was to revise and to reuse an outdated air-conditioning laboratory unit, by using improved methods. General equations were defined separately for each part and cell of this air conditioning system. Using these equations Matlab/Simulink models for every component were created. The Matlab/Simulink models were combined and verified with theoretical results. The simulation results show that theoretical results are compatible with the simulation results. These results were tested for input and output air enthalpy values and for humidity values. In addition, air mass flow rates for the number of different fan speeds were compared. The coherent simulation results showed that the general model of the air conditioning system, designed in Matlab/Simulink, behaves correctly. This model will be used in the future studies for comparison of real system results with simulation results.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 2.

Tytuł:: The Effect of General Low Frequency Vibration on Energy Balance of a Human Being
Autorzy:: Damijan, Z.
Uhryński, A.
Tematy:: 87.50.yt
07.20.-n; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1177286.pdf Link otwiera się w nowym oknie
Opis:: The work presents the research and analysis concerning general low frequency vibration and its effect on energy balance of a human organism (a comparison with a control group). The research was conducted in two phases: a group exposed to vibration and a control group. An exposed group (28 participants) took part in 19 training sessions, each lasting 20 min, of low frequency vibration (around 3.2 Hz in standing position) applied to each participant at fixed time of the day. Before and after the session, the thermographic images were taken and deep temperature was taken too. The control group (33 participants) also took part in 19 everyday 20-min sessions with no vibrations and only measurements conducted. The results were analysed concerning statistics using Statistica. For the sake of the analysis the significance level was p = 0.05, the parametric T - test, and the non-parametric Kołmogorow-Smirnow tests were used for two groups of independent variables. Having conducted the research and analysis, one can state that 20-min exposure to low frequency vibration results in significant positive changes in chosen parameters.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 3.

Tytuł:: Study of the structure and thermal properties of intermetallics from Fe-Al system
Autorzy:: Śmiglewicz, A.
Rodak, K.
Tomaszewska, A.
Tematy:: 81.70.Pg
65.40.De
65.60.+a
07.20.-n; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1112888.pdf Link otwiera się w nowym oknie
Opis:: Selected alloys from the Fe-Al system are included into a group of materials on a matrix of intermetallic phases, and characteristic properties result from it and they constitute a resultant between properties of superalloys and ceramic materials. These materials are characterized, inter alia, by capacity for operating at elevated temperatures, as well as good strength related properties and resistance to oxidation and corrosion at an increased temperature. In addition, a low cost of alloy components and low density caused by aluminium content are their advantages. The basic reasons limiting application of alloys from Fe-Al system as construction materials are current: their low plasticity at room temperature, propensity for brittle cracking, low resistance at elevated temperature, and insufficient creep resistance. This unfavorable characteristics may be improved by adding to alloys such elements as molybdenum, zirconium, carbon, and boron, reducing the size of grains, increasing their purity, stabilizing the solid solution, and causing changes in phase transition temperatures. These alloys may be successfully manufactured by classic melting accompanied with refinement remelting, and ingot casting. In spite of additions and microadditions, grain refining of the initial structure of ingots manufactured in that way is rarely achieved, mainly because of low castability and high casting contraction. In this work we presented the results of structure analysis and investigations of the dilatometric study alloys on the base Fe-Al system. The alloys were obtained by classic casting technique. The studies were carried out on samples after casting and annealing. The phase transformation and thermal expansion investigations of the alloys from Fe-Al system with concentration of Fe-58Al were presented. The linear thermal expansion α was calculated by standard method. The α coefficient was noticed as a temperature function.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 4.

Tytuł:: Characterization of Temperature Field Distribution in Large-Size Paratellurite Crystals Applied in Acousto-Optic Devices
Autorzy:: Tretiakov, S.
Grechishkin, R.
Kolesnikov, A.
Kaplunov, I.
Yushkov, K.
Molchanov, V.
Linde, B.
Tematy:: 42.70.-a
42.79.-e
65.40.-b
07.20.-n; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1383374.pdf Link otwiera się w nowym oknie
Opis:: Temporal and spatial distribution of temperature field was studied in operating acousto-optic devices on base of large-size paratellurite crystals. The study was carried out in real time by means of thermal imaging technique. Dynamics of heat release in a hot deflector and a hot tunable filter was examined at different frequencies and driving electric power levels applied to piezoelectric transducers. The study was also based on measurements of standing wave ratio and analysis of the Smith charts.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 5.

Tytuł:: Magnetic Properties and Resistivity Measurement of Nanocrystalline $Cu_{70}Fe_{18}Co_{12}$ Alloys
Autorzy:: Laslouni, W.
Hamlati, Z.
Azzaz, M.
Tematy:: 81.07.-b
81.20.-n
81.20.Ev
81.07.Wx; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1401972.pdf Link otwiera się w nowym oknie
Opis:: The mechanical alloying process has been used to prepare nanocrystalline $Cu_{70}Fe_{18}Co_{12}$ alloy from elemental Cu, Fe and Co powders in a planetary ball mill under argon atmosphere. The interdiffusion of Cu, Fe and Co leads to a heterogeneous solid solution with Cu-Fe-Co rich environments after 12 h of milling. The end product is a mixture of a highly disordered structure, fcc-Cu (Fe-Co), phase having different microstructural and structural parameters. For all the elaborate series, the evolution of coercive field and the remanence according to the time of milling is analyzed. The coercivity, $H_{c}$, decreases rapidly up to 8 h of milling to about 0.3 A/m and then the coercivity, increases to a maximum at 54 h. The influence of the time of milling at the resistivity of these alloys is shown.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 6.

Tytuł:: Mesure de la Temperature Basees sur l'Observation du Premier Systéme Negatif de l'Azote
Temperature Measurements Based on the First Negative Spectrum of Nitrogen
Autorzy:: Nassar, H.
Czernichowski, A.
Tematy:: 33.10.-n
33.20.-t
07.20.Ka
78.40.-q; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1929529.pdf Link otwiera się w nowym oknie
Opis:: Noisy, non-resolved emission spectra of the (0,0) 391.4 nm N$\text{}_{2}$$\text{}^{+}$ molecular band are employed for the rotational (and in some case vibrational) temperature evaluation in different sources in the range of 320-7900 K when the apparatus function of the recording system is unknown. The following sources are examined: an ovoid-shaped transferred arc at atmospheric pressure, a low-pressure transferred arc, a high-voltage high-pressure electric discharge, a low-pressure radio-frequency discharge, and an atmospheric pressure laminar plasma jet. The described method is based on a normalization of the experimental spectrum with respect to the (0,0) band-head amplitude followed by a point-to-point comparison of the real spectrum with respect to a computer simulated spectrum using the best-square fit criterion. This criterion is found as the good one: the relative error on temperature evaluation had the same order of magnitude as the noise-to-signal ratio, even if the last one was relatively high. It was also found that the rotational and vibrational temperatures in the radio-frequency discharge are very different, which indicates an out of thermodynamic equilibrium characteristic of such a discharge. The proposed method of temperature evaluation is shown as quite precise and simple to use for even the non-spectroscopists.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 7.

Tytuł:: Electronic States and Structure of Dibenzo[j,lm]-phenanthro[5,4,3-abcd]perylene
Autorzy:: Marczyk, J.
Waluk, J.
Fetzer, J.
Tematy:: 07.65.-b
33.20.-t
33.10.-n; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1933561.pdf Link otwiera się w nowym oknie
Opis:: Electronic absorption and emission, fluorescence anisotropy and linear dichroism techniques were applied to dibenzo[j, lm]phenanthro[5,4,3-abcd]perylene in order to determine its electronic structure and check the possibility of existence of conformational isomers. The results indicate the presence of only one conformer. Its structure is proposed on the basis of the experimental data as well as molecular mechanics and quantum chemical calculations.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 8.

Tytuł:: Examples for the Industrial Use of Synchrotron Radiation
Autorzy:: Hormes, J.
Chauvistré, R.
Schmitt, W.
Pantelouris, M.
Tematy:: 07.85.+n
29.20.-c
32.30.Rj
78.70.Dm; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1920823.pdf Link otwiera się w nowym oknie
Opis:: Synchrotron radiation has become a valuable tool for many fields of basic research. Several of the methods which were here developed are also suitable for solving industrial problems. Perhaps the most promising ones are the various X-ray techniques, e.g. X-ray absorption spectroscopy (EXAFS and XANES) and X-ray fluorescence. In the following article the theoretical and experimental basis for these techniques is shortly introduced and some instructive examples for such applications for actual industrial problems are dicussed. In the last section, X-ray lithography for the production of microstructures is presented as an example where synchrotron radiation is already today used for industrial production.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 9.

Tytuł:: Measurement System for Parameter Estimation and Diagnostic of Ultrasonic Transducers
Autorzy:: Kluk, P.
Milewski, A.
Kardyś, W.
Kogut, P.
Michalski, P.
Tematy:: 43.35.-c
43.35.+d
43.38.+n
43.38.-p
84.37.+q
07.10.-h
46.40.-f
07.20.Dt; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1399367.pdf Link otwiera się w nowym oknie
Opis:: The paper presents an architecture and design of measurement system and methods for parameter estimation and diagnostic of ultrasonic transducers used in ultrasonic welding and cutting systems manufactured by Tele and Radio Research Institute. The key element of the ultrasonic welding and cutting system is a high power ultrasonic transducer implemented as a sandwich transducer consisting of a stack of piezoelectric ceramic rings mounted between two masses. High quality welding and cutting demand predetermined frequency characteristic of transducer impedance. Also important are: high energy efficiency, high coupling coefficient, low dielectric loss, and the optimal radiation pattern. In order to manufacture high quality and long-life transducers the piezoelectric rings must be selected and the sandwich transducers diagnosed on the basis of their measured parameters. Presented measurement system takes advantage of the virtual instrument technique in the NI LabVIEW environment. It uses Agilent U2761A Function Generator, U2531A Data Acquisition Unit, and the linear amplifier to measure impedance frequency characteristic in the frequency range of 10 kHz to 100 kHz. Moreover, the system can measure the vibration amplitude in the range of 1 μm up to 100 μm, using an optical sensor, and the temperature of the transducer using a pyrometer sensor.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 10.

Tytuł:: Field Assisted Sintering Technique Compaction of Ultrafine-Grained Binderless WC Hard Metals
Autorzy:: Dopita, M.
Salomon, A.
Chmelik, D.
Reichelt, B.
Rafaja, D.
Tematy:: 81.05.Je
81.05.Mh
81.07.-b
81.20.-n
81.20.Ev
62.20.Qp
62.20.mm; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1419115.pdf Link otwiera się w nowym oknie
Opis:: Tungsten carbide (WC) powder having a crystallite size around 55 nm and the Brunauer-Emmett-Teller specific surface area 2.75 $m^2//g$ was sintered using the field assisted sintering/spark plasma sintering technique. Sintered samples were investigated using different analytical methods providing detailed information on the microstructure and mechanical properties of materials. Density and porosity of specimens were determined using the Archimedes principle and optical and scanning electron micrographs. The X-ray diffraction investigations provided the information on the crystal real structure and crystallite sizes. The electron backscatter diffraction measurements yielded the details about the grain size, frequency, and distributions of grain boundaries. Finally, the essential mechanical properties of sintered samples were obtained from the hardness and fracture toughness measurements. The influences of individual sintering conditions: sintering temperature and sintering time especially, on the microstructure and mechanical properties of sintered specimens were derived. Fully compact samples having the Vickers hardness HV10 around 29 GPa and fracture toughness $K_{Ic}$ approximately 7.2 MPa $m^{1//2}$ were sintered from temperatures of 1800C and holding times 1 min. Specimens sintered at lower temperatures showed lower density which resulted in a significant drop in the sample hardness.
Dostawca treści:: Biblioteka Nauki

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