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Tytuł:
The Effect of Low Deformation Asymmetric Rolling on Microstructure and Texture of the Polycrystalline Copper
Autorzy:
Uniwersał, A.
Wróbel, M.
Wroński, S.
Kalemba-Rec, I.
Wroński, M.
Wierzbanowski, K.
Baczmański, A.
Bacroix, B.
Powiązania:
https://bibliotekanauki.pl/articles/353907.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
asymmetric rolling
polycrystalline copper
microstructure refinement
strip curvature
Opis:
In the most recent years the asymmetric rolling (AR) attracts attention of researchers and technologists. This process can improve some technological parameters (e.g. modification of rolling torque and load, power requirements, etc.) as well as provide the possibility of grain refinement in a relatively inexpensive way. Most of the reports concerning microstructural changes produced by AR refer to high deformations imposed in highly asymmetric conditions. However, such rolling conditions are difficult to control, so there are no prospects to their quick industrial implementation. The present paper refers to relatively low deformation and low asymmetry rate, that is much more interesting for the industry. It was shown that bending of the rolled band (important disadvantage of the AR technology) can be controlled by adjusting of the amount of deformation and asymmetry. It was also shown that ca. 30% reduction in thickness during cold rolling, together with a relatively low asymmetry, reduces significantly the grain size and produces a more fragmented microstructure inside grains of the polycrystalline copper comparing to the symmetric rolling (SR). The material hardness after AR is higher than after the SR. Moreover, the crystallographic texture asymmetry, expressed by its rotation around the transverse direction, is observed in the AR material.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 4; 2183-2188
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Production Line Modelling in Accordance with the Industry 4.0 Concept as an Element of Process Management in the Iron and Steel Industry
Autorzy:
Niekurzak, Mariusz
Kubińska-Jabcoń, Ewa
Powiązania:
https://bibliotekanauki.pl/articles/2023962.pdf
Data publikacji:
2021-12
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hot rolling
logistic model
mill
steel
strip
stock management
Opis:
Simulations are becoming one of the most important techniques supporting production preparation, even in those industrial sectors with atypical technological processes, such as in metallurgy, where there is a multiphase material flow. This is due to the fact that in the conditions of a market economy, enterprises have to solve more and more complex problems in a shorter time. On the basis of the existing production process and the knowledge of the flow characteristics in a given process, a model is built, which, when subjected to simulation tests, provides experimental results in the scope of the defined problem. The use of computer techniques also creates new possibilities for the rational use of the reserves inherent in each technological process. Taking into account the existing demand and the state of modern technology, the computer model can be a source of information for further analysis and decision-making processes supporting company management. At work a model of the logistic system was made on the example of a hot-rolled steel strip mill, on which simulation experiments were carried out to improve the effectiveness and efficiency of the analysis production line. The presented article aims to disseminate the idea of ??Industry 4.0 in Polish companies from the manufacturing industry sector, taking into account simulation techniques.
Źródło:
Management and Production Engineering Review; 2021, 14, 4; 3-12
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tsunami event identified in a sedimentary record of the Gaza Strip, Palestine
Autorzy:
Ubeid, Khalid Fathi
Powiązania:
https://bibliotekanauki.pl/articles/2025075.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tsunami
sedimentology
pottery shard
rip-up clast
Gaza Strip
Opis:
The outcrop of the tsunami deposits, about 6 m thick, is located in the archaeological site Tel Askan in the Al Zhraa locality, southwest of the Gaza City. These deposits are unconformably underlain by sand dunes and sharply overlain by a palaeosol. They are pale gray sands mixed with volcanic ash and fine-grained deposits, and are intercalated with peat, few centimetres thick. The sand-sized grains are well rounded and well sorted, and consist mainly of quartz and subordinate of feldspar. Both macro- and microfossils were observed from tsunami deposits. Additionally, rip-up clasts and pottery shards were observed, indicating higher-flow regime. The potteries in tsunami deposits provide evidence for tsunami inundation at distance of about 1 km from the present shoreline.
Źródło:
Studia Quaternaria; 2021, 38, 1; 43-51
1641-5558
2300-0384
Pojawia się w:
Studia Quaternaria
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dual Band Integrated Wideband Multi Resonating Patch Antenna for C–Band and Ku–Band Applications
Autorzy:
Srivastava, Karunesh
Singh, Sweta
Singh, Aditya Kumar
Singh, Rajeev
Powiązania:
https://bibliotekanauki.pl/articles/226214.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
micro-strip antenna
dual-band
wideband
cband
ku-band
HFSS
Opis:
A wideband antenna with dual band characteristic at 5.33/14.3GHz with resonating frequencies for wireless applications is presented. The strategy of the design is to introduce multiband in antenna band. Bandwidth of the antenna increases by embedding annular ring on the radiating patch and four bands are achieved by introducing coupling gap between the patches. Surface current distribution is analyzed at different resonating frequencies for understanding the radiation mechanism and effect of annular ring. The antenna parameters such as return loss, radiation pattern, gain, VSWR and group delay are discussed. The impedance bandwidth of the proposed dual band antenna at lower resonant frequency is 12.7% (simulated) and 9.8 % (measured) whereas at upper resonant frequency is 15.3 % (simulated) and 13.97 % (measured).
Źródło:
International Journal of Electronics and Telecommunications; 2019, 65, 3; 347-352
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Analysis of the Asymmetric Plate Rolling Process in the Finishing Stand 3600
Analiza asymetrycznego procesu walcowania blach grubych w klatce wykańczającej 3600
Autorzy:
Kawałek, A.
Dyja, H.
Knapiński, M.
Banaszek, G.
Kwapisz, M.
Powiązania:
https://bibliotekanauki.pl/articles/356016.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
numerical modelling
asymmetric rolling
strip shape
strip bending
pressure of the metal on the rolls
modelowanie numeryczne
walcowanie asymetryczne
zmiana kształtu
wyginanie pasma
Opis:
In order to enhance the quality of plates, various solutions are being implemented, including normalizing rolling, the process of rolling followed by accelerated cooling, as well as new roll gap control systems. The hydraulic positioning of rolls and the working roll bending system can be mentioned here. The implementation of those systems results in increased loads of the rolling stands and working tools, that is the rolls. Another solution aimed at enhancing the cross-sectional and longitudinal shape of rolled plate is the introduction of asymmetric rolling, which consists in the intentional change of the stress and strain state in the roll gap. Asymmetric rolling systems have been successfully implemented in strip cold rolling mills, as well as in sheet hot rolling mills. The paper present results of studies on the effect of roll rotational speed asymmetry and other rolling process parameters on the change in the shape of rolled strip and the change of rolls separating force for the conditions of normalizing rolling of plates in the finishing stand. The variable process parameters were: the roll rotational speed asymmetry factor, av; the strip shape factor, h0/D; and the relative rolling reduction, ε. Working rolls of the diameter equal to 1000 mm and a constant lower working roll rotational speed of n = 50 rpm were assumed for the tests. The asymmetric rolling process was run by varying the rotational speed of the upper roll, which was lower than that of the lower roll. The range of variation of the roll rotational speed factor, av =vd/vg, was 1.01÷1.15. A strip shape factor of h0/D = 0.05÷0.014 was assumed. The range of rolling reductions applied was ε = 0.08÷0.50. The material used for tests was steel of the S355J2G3 grade. For the simulation of the three-dimensional plastic flow of metal in the roll gap during the asymmetric hot rolling of plates, the mathematical model of the FORGE 2008 ® program was used. For the mathematical description of the effect of rolling parameters on the strip curvature and rolls separating force the special multivariable polynomial interpolation was used. This method of tensor interpolation in Borland Builder programming environment was implemented. On the basis of the carried out analysis can be state, that by using the appropriate relative rolling reduction and working roll peripheral speed asymmetry factor for a given feedstock thickness (strip shape ratio) it is possible to completely eliminate the unfavorable phenomenon of strip bending on exit from the roll gap, or to obtain the permissible strip curvature which does not obstructs the free feed of the strip to the next pass or transferring the plate to the accelerated plate cooling stations. Additionally by introducing the asymmetric plate rolling process through differentiating working roll peripheral speeds, depending on the asymmetry factor used, the magnitude of the total roll separating force can be reduced and, at the same time, a smaller elastic deflection of rolling stand elements can be achieved. As a result smaller elastic deflection of the working rolls, smaller dimensional deviations across its width and length finished plate can be obtained.
W celu poprawy jakości blach grubych stosowane są różne rozwiązania obejmujące walcowanie normalizujące, przyspieszone chłodzenie po walcowaniu, jak również nowe systemy sterowania szczelina walcownicza. Należy również wspomnieć o systemach hydraulicznej nastawy walców oraz przeginania walców roboczych. Zastosowania tych systemów powoduje wzrost obciążenia klatki walcowniczej i jej osprzętu, jak również walców. Innym rozwiązaniem powodującym poprawę wzdłużnego i poprzecznego kształtu walcowanych blach jest wprowadzenie walcowania asymetrycznego, które wprowadza kontrolowana zmianę stanu naprężenia i odkształcenia w kotlinie walcowniczej. Systemy asymetrycznego walcowania były skutecznie zastosowane podczas walcowania taśm na zimno oraz w walcowniach gorących podczas walcowania cienkich blach. W artykule przedstawiono wyniki badań wpływu asymetrii prędkości obrotowej walców i innych parametrów procesu na zmianę kształtu walcowanego pasma oraz zmianę siły nacisku na walce w warunkach walcowania normalizującego blach grubych w klatce wykańczającej. Zmiennymi parametrami procesu były: współczynnik asymetrii prędkości obrotowej walców, av; współczynnik kształtu pasma, h0/D; oraz gniot względny, ε. Do badań założono średnice walców roboczych równa 1000 mm i stałą wartość prędkości obrotowej dolnego walca n = 50 obr/min. Warunki asymetrycznego procesu walcowania uzyskano przez zróżnicowanie prędkości obrotowej górnego walca, która przyjmowano niższą niż walca dolnego. Zakres zmian współczynnika asymetrii prędkości obrotowych av =vd/vg przyjeęo: 1,01÷0,15. Założono współczynnik kształtu pasma h0/D w zakresie 0,05÷0,014 oraz przyjęto wartości gniotu względnego ε w przedziale: ε = 0.08÷0.50. Badanym materiałem była stal w gatunku S355J2G3. Do symulacji trójwymiarowego, plastycznego płynięcia metalu w kotlinie walcowniczej podczas asymetrycznego walcowania blach grubych na gorąco wykorzystano model matematyczny programu FORGE 2008 ® . W celu matematycznego opisu wpływu parametrów walcowania na krzywiznę pasma i siłę nacisku metalu na walce zastosowano interpolacje wielomianem wielu zmiennych. Metodę interpolacji tensorowej zaimplementowano w środowisku programowym Borland Builder. Na podstawie przeprowadzonej analizy można stwierdzić, że zastosowanie odpowiedniego gniotu względnego i współczynnika asymetrii prędkości obwodowych walców, dla danej wartości wysokości początkowej pasma (współczynnika kształtu pasma) umożliwia całkowite wyeliminowanie niekorzystnego zjawiska wyginania się pasma po wyjściu z kotliny walcowniczej lub uzyskanie dopuszczalnej krzywizny pasma, która nie zakłóca wprowadzenia pasma do kolejnego przepustu lub jego transportu do urządzeń chłodzacych. Dodatkowo przez wprowadzenie procesu walcowania asymetrycznego, w zależności od zastosowanego współczynnika asymetrii, można uzyskać zmniejszenie siły nacisku metalu na walce, a jednocześnie zachodzi zmniejszenie sprężystego ugięcia elementów klatki walcowniczej. Dzięki zmniejszeniu sprężystego ugięcia klatki walcowniczej uzyskuje się końcową blachę o zmniejszonych odchyłkach wymiarowych wzdłuż jej szerokości i długości.
Źródło:
Archives of Metallurgy and Materials; 2014, 59, 4; 1533-1538
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of a rapid immunochromatographic assay for detection of antibodies against porcine epidemic diarrhea virus
Autorzy:
Li, R.
Ma, J.
Tian, X.
Yu, Y.
Qiao, S.
Wang, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2087760.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
porcine epidemic diarrhea virus
immunochromatographic test strip
nucleocapsid protein
diagnosis
Źródło:
Polish Journal of Veterinary Sciences; 2018, 21, 1; 139-147
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Multi-label Transformation Framework for the Rectangular 2D Strip-Packing Problem
Autorzy:
Neuenfeldt Júnior, Alvaro
Francescatto, Matheus
Stieler, Gabriel
Disconzi, David
Powiązania:
https://bibliotekanauki.pl/articles/2023851.pdf
Data publikacji:
2021-12
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
strip packing problem
data mining
multi-label transformation
classification analysis
heuristics
Opis:
The present paper describes a methodological framework developed to select a multi-label dataset transformation method in the context of supervised machine learning techniques. We explore the rectangular 2D strip-packing problem (2D-SPP), widely applied in industrial processes to cut sheet metals and paper rolls, where high-quality solutions can be found for more than one improvement heuristic, generating instances with multi-label behavior. To obtain single-label datasets, a total of five multi-label transformation methods are explored. 1000 instances were generated to represent different 2D-SPP variations found in real-world applications, labels for each instance represented by improvement heuristics were calculated, along with 19 predictors provided by problem characteristics. Finally, classification models were fitted to verify the accuracy of each multi-label transformation method. For the 2D-SPP, the single-label obtained using the exclusion method fit more accurate classification models compared to the other four multi-label transformation methods adopted.
Źródło:
Management and Production Engineering Review; 2021, 14, 4; 27-37
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the mechanics and micro/macroeconomics of multiple strip-shaped pillar recovery
Autorzy:
Chen, Qingfa
Wu, Shiwei
Zhao, Fuyu
Powiązania:
https://bibliotekanauki.pl/articles/219858.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mechanika
szalunek kopalni
bezpieczeństwo kopalni
multiple strip-shaped pillars
recovery
mechanics
macroeconomic
Opis:
The structural system of a multiple strip-shaped pillar-roof is common in underground mine exploitation, and research on its mechanics and micro/macroeconomics is meaningful for utilizing strip-shaped pillar resources. A general model of the structural system of a multiple strip-shaped pillar-roof was established, the deformation mechanism of the model was analysed by material mechanics, and the deflection curve equations of the model were obtained. Based on the stress strain constitutive relation of the strip pillar and cusp catastrophe theory, the nonlinear dynamic instability mechanism of the structural system of a multiple strip-shaped pillar-roof was analysed, and the expressions of the pillar width for maintaining the stability of different types of structural systems were derived. The benefits of different structural systems were calculated using micro/macroeconomic theory, the type of the structural system was determined, and different recovery schemes were obtained. Theoretical application research was applied to a large manganese mine, and the results demonstrate that no pillar recovery was needed in 2016, a 9-m wide artificial pillar could be built to replace a pillar in 2017, and the construction of 14-m wide artificial pillars can be conducted in 2018.
Źródło:
Archives of Mining Sciences; 2020, 65, 1; 19-33
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Repairing and strengthening of elliptical paraboloid reinforced concrete shells with openings
Autorzy:
Meleka, N. N.
Safan, M. A.
Bashandy, A. A.
Abd-Elrazek, A. S.
Powiązania:
https://bibliotekanauki.pl/articles/230114.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
powłoka żelbetowa
otwór
naprawa
wzmacnianie
taśma stalowa
zaprawa naprawcza
zaprawa żywiczna
taśma GFRP
reinforced concrete shell
opening
repair
strengthening
steel strip
repair mortar
resinous mortar
GFRP strip
Opis:
This investigation is carried out to evaluate the repair and strengthening the techniques of elliptical paraboloid reinforced concrete shells with openings. An experimental program of several different techniques in repair and strengthening is executed. The materials, which are considered for strengthening, are; Glass fiber reinforced polymers GFRP at different position of the shell bottom surface, steel strip and external tie. They loaded by four concentrated loads affected on the corners of the opening. The initial and failure loads as well as the crack propagation for the tested shells at different loading stages, defl ections and failure load for repaired and shells are recorded. A non-linear computer program based on finite element techniques is used to study the behavior of these types of shells. Geometric and materials nonlinearities are considered in the analysis. The efficiency and accuracy of computer program are verifi ed by comparing the program results with those obtained experimentally for the control shell with opening and strengthened shells.
Źródło:
Archives of Civil Engineering; 2013, 59, 3; 401-420
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strengthening of slab-column connections with CFRP strips
Wzmacnianie połączeń płyta-słup za pomocą taśm CFRP
Autorzy:
Urban, T.
Tarka, J.
Powiązania:
https://bibliotekanauki.pl/articles/230143.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wzmacnianie
połączenie płyta-słup
taśma kompozytowa
przebicie
CFRP
strengthening
slab-column connection
composite strip
punching
Opis:
The paper describes experimental research of slab-column connections examined on specimen designed as a part of reinforced concrete structure with flat slabs. The aim of the research was to verify the efficiency of slab reinforcement concept against punching shear by increasing slab's mechanical reinforcement ratio by applying additional external reinforcement in the form of carbon fiber reinforced polymer (CFRP) strips. The capacity enhancement in comparison to unstrengthened slab obtained 36%.
Artykuł przedstawia badania doświadczalne płyt żelbetowych, przyjętych jako fragment realnej konstrukcji żelbetowej z płaskimi stropami. Celem badań była weryfikacja efektywności wzmocnienia połączenia płyty ze słupem na przebicie poprzez zwiększenie mechanicznego stopnia zbrojenia (mocy zbrojenia) za pomocą dodatkowych zewnętrznych taśm karbodurowych (CFRP). Uzyskano wzrost nośności na przebicie do 36% względem modelu odniesienia.
Źródło:
Archives of Civil Engineering; 2010, 56, 2; 193-212
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Autoetnografia 2.0
Autoethnography 2.0
Autorzy:
Darmach, Krystian
Powiązania:
https://bibliotekanauki.pl/articles/1373288.pdf
Data publikacji:
2017-07-10
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Möbius Strip
autoetnografia
doświdczenie
fenomenologia
dziennik
metodologia
politropia
wstęga Möbiusa
autoethnography
anthropological experience
phenomenology
diary
methodology
polytropos
Opis:
This text is a methodological diary—a meta-autoethnography, an attempt to report on the course and formation of auto-reflection on various aspects of autoethnography in the broad sense. It is the reinterpretation of selected fragments of the author’s own texts of an autoethnographic profile, and a description of the process by which the concept of the essay emerged. It addresses the role of autoethnography in the anthropological cognitive process and autoethnography’s contemporary methodological status. The author intends to show how his reflections were shaped and to open the door to the scholar’s “kitchen” by describing how the questions, phrases, and ideas inscribed in his notebook served as departure points for further reflection and representation in the essay. He tells how his thoughts were structured, what reading and ideas inspired him, and finally, how these often laconic, fragmentary, and disorganized notes and observations brought together the issues and themes worthy of anthropological expansion and consideration.
Źródło:
Kultura i Społeczeństwo; 2017, 61, 3; 87-101
2300-195X
Pojawia się w:
Kultura i Społeczeństwo
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on application of strip backfilling mining technology – a case study
Autorzy:
Xing, Wenbin
Huang, Wanpeng
Feng, Fan
Powiązania:
https://bibliotekanauki.pl/articles/2073880.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
technologia budowlana
skała węglowa
symulacja numeryczna
coal gangue
strip backfilling mining
numerical simulation
scheme design
construction technology
Opis:
Strip backfilling mining technology is of great significance for eliminating coal gangue, improving coal recovery rate, harmonizing the development between resources and environment in diggings. This paper firstly analyzed the roof control mechanism, the deformation and failure mechanism and characteristics of the filling body through theoretical analysis. Then, through numerical simulation combined with the geological conditions on site, a gangue strip filling scheme was designed for the 61303 working face of the 13th layer of the rear group coal of the Wennan Coal Mine in Shandong Province, and the filling scheme of filling 50 m and leaving 25 m was determined. Finally, an on-site engineering test was carried out on the 61303 working face. Through the analysis of the measured data of “three quantities” after the filling test, it can be seen that the test has achieved a good engineering application effect and verified the rationality of the filling scheme design. It solves the coal gangue problem, improves the resource recovery rate, and provides a reference for other similar mines.
Źródło:
Archives of Mining Sciences; 2021, 66, 4; 595--609
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study of the strip coal pillar models failure with different roof and floor conditions
Autorzy:
Qu, Xiao
Chen, Shaojie
Yin, Dawei
Liu, Shiqi
Powiązania:
https://bibliotekanauki.pl/articles/2073871.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
kopalnia
filar węglowy
górnictwo odkrywkowe
“roof-strip coal pillar-floor” combined specimen
failure characteristics
acoustic emission
laboratory experiment
Opis:
In order to study the failure mechanism and characteristics for strip coal pillars, a monitoring device for strip coal pillar uniaxial compression testing was developed. Compression tests of simulated strip coal pillars with different roof and floor rock types were conducted. Test results show that, with increasing roof and floor strength, compressive strength and elastic modulus of “roof-strip coal pillar-floor” combined specimens increase gradually. Strip coal pillar sample destruction occurs gradually from edge to the interior. First macroscopic failure occurs at the edge of the middle upper portion of the specimen, and then develops towards the corner. Energy accumulation and release cause discontinuous damage in the heterogeneous coal-mass, and the lateral displacement of strip coal pillar shows step and mutation characters. The brittleness and burst tendency of strip coal pillar under hard surrounding rocks are more obvious, stress growth rate decreases, and the rapid growth acoustic emission (AE) signal period can be regarded as a precursor for instability in the strip coal pillar. The above results have certain theoretical value for understanding the failure law and long-term stability of strip coal pillars.
Źródło:
Archives of Mining Sciences; 2021, 66, 3; 475--490
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on some of the strength properties of soft clay stabilized with plastic waste strips
Autorzy:
Kabeta, Worku Firomsa
Powiązania:
https://bibliotekanauki.pl/articles/2173989.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
pasek plastykowy
stabilizacja
właściwości wytrzymałościowe
glina miękka
materiał odpadowy
plastic strip
stabilization
strength properties
soft clay
waste material
Opis:
It is well known that if plastic wastes are not well managed, it has a negative impact on the environment as well as on human health. In this study, recycling plastic waste in form of strips for stabilizing weak subgrade soil is proposed. For this purpose, a weak clay soil sample was mixed with 0.2%, 0.3%, and 0.4% of plastic strips by weight of soil, and the experimental results were compared to the control soil sample with 0% plastic. Laboratory tests on the Standard compaction test, Unconfined compression test (UCS), and California bearing ratio (CBR) were conducted according to the American Society for Testing and Materials (ASTM). The results of the study reveal that there are significant improvements in the strength of weak soil stabilized with plastic waste strips. Accordingly, the Standard Proctor test shows that there is a small increment in the maximum dry density of the soil when it is mixed with plastic strips. The result from the CBR test shows that there is a significant increment of CBR value with the plastic strip content. The unconfined compressive strength test also shows that increasing the percentage of plastic strips from 0 to 0.4% resulted in increased strength of soil by 138% with 2 cm length plastic strips. Therefore, this study recommends the application of plastic strips for improvement of the strength of soft clay for subgrade construction in civil engineering practice as an alternative weak soil stabilization method.
Źródło:
Archives of Civil Engineering; 2022, 68, 3; 385--395
1230-2945
Pojawia się w:
Archives of Civil Engineering
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

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