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Wyszukujesz frazę "Kozieł, A." wg kryterium: Autor


Wyświetlanie 1-9 z 9
Tytuł:
Improving environmental odor measurements : comparison of lab-based standard method and portable odor measurement technology
Autorzy:
Maurer, D. L.
Bragdon, A. M.
Short, B. C.
Ahn, H.
Koziel, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/204983.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
odor
volatile organic compounds
air quality measurements
standardization
olfactometry
Opis:
Current standard odor measurement methods are lab-based and require substantial investment in hardware, sample collection, training, and maintenance. Odor samples must be collected in the field using bags and brought to the lab to test. This can be a time-consuming process, with the possibility of the sample loss. The actual odor measurements are based on dilution olfactometry, embodied in the AC’SCENT® International Olfactometer, following the ASTM E679-04 standard. In recent years a portable olfactometer, the Scentroid SM100i, has been developed for odor measurements. The portable olfactometer has many advantages over lab-based standard method, especially the lower cost-per-sample. However, very little is known about the performance and reliability of portable olfactometer where the dilutions are controlled with orifices in metallic plates. It is important to evaluate the Scentroid SM100i accuracy to determine the usefulness of using it as a comparable technology for odor measurements. The main objective of this research is to compare the performance of the lab-based ASTM E679-04 method with portable odor measurement technology. Specific objectives include: (1) determining the accuracy of the dilution ratios specified by the manufacturer of both the AC’SCENT International Olfactometer and the Scentroid SM100i; (2) comparing results between olfactometers using n-butanol, a commonly used standard gas in the olfactometry field, and (3) determining the accuracy of odor measurement using real odor samples collected from livestock farms in Iowa. The AC’SCENT olfactometer had an average percent error between the factory specifications and measured dilution ratios of 5.23% compared with 14.1% for Scentroid SM100i (using plate i-2 with dilution range most comparable to the AC’SCENT olfactometer). The use of other dilution plates resulted in average percent errors ranging from 9.68% to 25.31%. The Scentroid SM100i deviated from the manufacturer specifications for flowrates and dilution ratios, but these flowrates were generally consistent with each dilution setting. Overall, the Scentroid SM100i overestimated the odor concentrations with the mean difference of 22.9% (ranging from 0.95% to 93.34%). When the post-measurement adjustment using dilution correction was made, the mean percent average difference was 11.8%.
Źródło:
Archives of Environmental Protection; 2018, 44, 2; 100-107
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computationally Efficient Two-Objective Optimization of Compact Microwave Couplers through Corrected Domain Patching
Autorzy:
Kozieł, S.
Bekasiewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/221065.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
computer-aided design
compact circuits
microwave couplers
multi-objective optimization
domain patching
surrogate modelling
response correction
Opis:
Finding an acceptable compromise between various objectives is a necessity in the design of contemporary microwave components and circuits. A primary reason is that most objectives are at least partially conflicting. For compact microwave structures, the design trade-offs are normally related to the circuit size and its electrical performance. In order to obtain comprehensive information about the best possible trade-offs, multi-objective optimization is necessary that leads to identifying a Pareto set. Here, a framework for fast multi-objective design of compact micro-strip couplers is discussed. We use a sequential domain patching (SDP) algorithm for numerically efficient handling of the structure bandwidth and the footprint area. Low cost of the process is ensured by executing SDP at the low-fidelity model level. Due to its bi-objective implementation, SDP cannot control the power split error of the coupler, the value of which may become unacceptably high along the initial Pareto set. Here, we propose a procedure for correction of the S-parameters’ characteristics of Pareto designs. The method exploits gradients of power split and bandwidth estimated using finite differentiation at the patch centres. The gradient data are used to correct the power split ratio while leaving the operational bandwidth of the structure at hand intact. The correction does not affect the computational cost of the design process because perturbations are pre-generated by SDP. The final Pareto set is obtained upon refining the corrected designs to the high-fidelity EM model level. The proposed technique is demonstrated using two compact microstrip rat-race couplers. Experimental validation is also provided.
Źródło:
Metrology and Measurement Systems; 2018, 25, 1; 139-157
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rapid Design Optimization of Multi-Band Antennas by Means of Response Features
Autorzy:
Kozieł, S.
Bekasiewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/221503.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
antenna design
antenna measurements
computer-aided design
surrogate modelling
feature-based optimization
Opis:
This work examines the reduced-cost design optimization of dual- and multi-band antennas. The primary challenge is independent yet simultaneous control of the antenna responses at two or more frequency bands. In order to handle this task, a feature-based optimization approach is adopted where the design objectives are formulated on the basis of the coordinates of so-called characteristic points (or response features) of the antenna response. Due to only slightly nonlinear dependence of the feature points on antenna geometry parameters, optimization can be attained at a low computational cost. Our approach is demonstrated using two antenna structures with the optimum designs obtained in just a few dozen of EM simulations of the respective structure.
Źródło:
Metrology and Measurement Systems; 2017, 24, 2; 337-346
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Rapid Re-Design of UWB Antennas with Respect to Substrate Permittivity
Autorzy:
Koziel, S.
Bekasiewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/221869.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
antenna design
geometry scaling
simulation-driven optimization
surrogate modeling
inverse modeling
substrate properties
Opis:
Re-design of a given antenna structure for various substrates is a practically important issue yet non trivial, particularly for wideband and ultra-wideband antennas. In this work, a technique for expedited redesign of ultra-wideband antennas for various substrates is presented. The proposed approach is based on inverse surrogate modeling with the scaling model constructed for several reference designs that are optimized for selected values of the substrate permittivity. The surrogate is set up at the level of coarse-discretization EM simulation model of the antenna and, subsequently, corrected to provide prediction at the high-fidelity EM model level. The dimensions of the antenna scaled to any substrate permittivity within the region of validity of the surrogate are obtained instantly, without any additional EM simulation necessary. The proposed approach is demonstrated using an ultra-wideband monopole with the permittivity scaling range from 2.2 to 4.5. Numerical validation is supported by physical measurements of the fabricated prototypes of the re-designed antennas.
Źródło:
Metrology and Measurement Systems; 2016, 23, 4; 513-520
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent developments in simulation-driven multi-objective design of antennas
Autorzy:
Koziel, S.
Bekasiewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/201914.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
computer-aided design
CAD
antenna design
multi-objective optimization
surrogate models
evolutionary algorithms
projektowanie wspomagane komputerowo
projektowanie anteny
model zastępczy
algorytmy ewolucyjne
Opis:
This paper addresses computationally feasible multi-objective optimization of antenna structures. We review two recent techniques that utilize the multi-objective evolutionary algorithm (MOEA) working with fast antenna replacement models (surrogates) constructed as Kriging interpolation of coarse-discretization electromagnetic (EM) simulation data. The initial set of Pareto-optimal designs is subsequently refined to elevate it to the high-fidelity EM simulation accuracy. In the first method, this is realized point-by-point through appropriate response correction techniques. In the second method, sparsely sampled high-fidelity simulation data is blended into the surrogate model using Co-kriging. Both methods are illustrated using two design examples: an ultra-wideband (UWB) monocone antenna and a planar Yagi-Uda antenna. Advantages and disadvantages of the methods are also discussed.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2015, 63, 3; 781-789
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Novel Structure and Design Optimization of Compact Spline-Parameterized UWB Slot Antenna
Autorzy:
Koziel, S.
Bekasiewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/221205.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compact antennas
computer-aided design (CAD)
EM-driven design
UWB antennas
slot antennas
surrogate-based optimization
Opis:
In this paper, a novel structure of a compact UWB slot antenna and its design optimization procedure has been presented. In order to achieve a sufficient number of degrees of freedom necessary to obtain a considerable size reduction rate, the slot is parameterized using spline curves. All antenna dimensions are simultaneously adjusted using numerical optimization procedures. The fundamental bottleneck here is a high cost of the electromagnetic (EM) simulation model of the structure that includes (for reliability) an SMA connector. Another problem is a large number of geometry parameters (nineteen). For the sake of computational efficiency, the optimization process is therefore performed using variable-fidelity EM simulations and surrogate-assisted algorithms. The optimization process is oriented towards explicit reduction of the antenna size and leads to a compact footprint of 199 mm2 as well as acceptable matching within the entire UWB band. The simulation results are validated using physical measurements of the fabricated antenna prototype.
Źródło:
Metrology and Measurement Systems; 2016, 23, 4; 637-643
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Suppressing Side-Lobes of Linear Phased Array of Micro-Strip Antennas with Simulation-Based Optimization
Autorzy:
Kozieł, S.
Ogurtsov, S.
Bekasiewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/220985.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
linear antenna array
micro-strip antenna array
phased antenna array
antenna optimization
antenna array optimization
simulation-based optimization
surrogate model
Opis:
A simulation-based optimization approach to design of phase excitation tapers for linear phased antenna arrays is presented. The design optimization process is accelerated by means of Surrogate-Based Optimization (SBO); it uses a coarse-mesh surrogate of the array element for adjusting the array’s active reflection coefficient responses and a fast surrogate of the antenna array radiation pattern. The primary optimization objective is to minimize side-lobes in the principal plane of the radiation pattern while scanning the main beam. The optimization outcome is a set of element phase excitation tapers versus the scan angle. The design objectives are evaluated at the high fidelity level of description using simulations of the discrete electromagnetic model of the entire array so that the effects of element coupling and other possible interaction within the array structure are accounted for. At the same time, the optimization process is fast due to SBO. Performance and numerical cost of the approach are demonstrated by optimizing a 16-element linear array of microstrip antennas. Experimental verification has been carried out for a manufactured prototype of the optimized array. It demonstrates good agreement between the radiation patterns obtained from simulations and from physical measurements (the latter constructed through superposition of the measured element patterns).
Źródło:
Metrology and Measurement Systems; 2016, 23, 2; 193-203
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design Optimization and Trade-Offs of Miniaturized Wideband Antenna for Internet of Things Applications
Autorzy:
ul Haq, M. A.
Kozieł, S.
Powiązania:
https://bibliotekanauki.pl/articles/220987.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compact antennas
internet of things (IoT)
communication devices
numerical optimization
footprint-reduction-oriented design
Opis:
Internet of Things (IoT) will play an important role in modern communication systems. Thousands of devices will talk to each other at the same time. Clearly, smart and efficient hardware will play a vital role in the development of IoT. In this context, the importance of antennas increases due to them being essential parts of communication networks. For IoT applications, a small size with good matching and over a wide frequency range is preferred to ensure reduced size of communication devices. In this paper, we propose a structure and discuss design optimization of a wideband antenna for IoT applications. The antenna consists of a stepped-impedance feed line, a rectangular radiator and a ground plane. The objective is to minimize the antenna footprint by simultaneously adjusting all geometry parameters and to maintain the electrical characteristic of antenna at an acceptable level. The obtained design exhibits dimensions of only 3.7 mm × 11.8 mm and a footprint of 44 mm2, an omnidirectional radiation pattern, and an excellent pattern stability. The proposed antenna can be easily handled within compact communication devices. The simulation results are validated through measurements of the fabricated antenna prototype.
Źródło:
Metrology and Measurement Systems; 2017, 24, 3; 463-471
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure of the amorphous-crystalline Fe66Cu6B19Si5Nb4 alloy obtained by the melt-spinning process
Struktura amorficzno-krystalicznego stopu Fe66Cu6B19Si5Nb4 otrzymanego metodą melt-spinning
Autorzy:
Kozieł, T.
Latuch, J.
Zielińska-Lipiec, A.
Powiązania:
https://bibliotekanauki.pl/articles/355938.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metallic glasses
amorphous/crystalline composites
melt-spinning
szkło metaliczne
kompozyty amorficzno-krystaliczne
metoda melt-spinning
Opis:
This paper presents structure investigations of the rapidly cooled Fe66Cu6B19Si5Nb4 alloy. A proper selection of chemical composition enabled in-situ formation of the amorphous-crystalline composite during the melt spinning process. Liquid phase separation into the Fe-rich and the Cu-rich phases was confirmed. The microstructures of alloy, melt-spun from 1723 and 1773 K, are composed of the Fe-rich amorphous matrix and Cu-rich spherical crystalline precipitates. For the higher melt-ejection temperature, no coarse precipitates could be observed. Amorphous nature of the Fe-rich matrix was confirmed by presence of a broad diffraction maximum on the X-ray diffraction patterns, a halo ring on the electron diffraction pattern as well as presence of exothermic effects, related to the crystallization of the Fe-rich amorphous matrix, in the differential scanning calorymetry. Beside presence of copper, revealing positive heat of mixing with iron, relatively large supercooled liquid region, was noticed.
Praca przedstawia badania kompozytu amorficzno-krystalicznego otrzymanego w stopie Fe66Cu6B19Si5Nb4. Badania obejmowały rentgenowską analizę fazową (XRD), skaningową kalorymetrie różnicową (DSC), mikroskopię swietlną (LM), skaningową mikroskopię elektronową (SEM) i transmisyjną mikroskopię elektronową (TEM). Odpowiedni dobór składu chemicznego umożliwił uzyskanie kompozytu amorficzno-krystalicznego dzięki wykorzystaniu zjawiska podziału w stanie ciekłym w efekcie dodatniego ciepła tworzenia roztworu pomiędzy żelazem i miedzią. Mikrostruktury badanego stopu, po odlaniu z temperatury 1723 i 1773 K, składają się z amorficznej osnowy bogatej w żelazo i krystalicznych kulistych wydzieleń bogatych w miedź. Dla wyższej temperatury odlewania nie obserwowano dużych wydzieleń. Obecność fazy amorficznej została potwierdzona poprzez obecność halo na dyfrakcji elektronowej oraz efekt cieplny egzotermiczny w badaniach skaningowej kalorymetrii różnicowej, związany z krystalizacją osnowy bogatej w żelazo. Pomimo dodatku miedzi, wykazującej dodatnie ciepło tworzenia roztworu z żelazem, wyznaczony zakres cieczy przechłodzonej jest względnie duży.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 2; 601-605
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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