2,020,096 research outputs found
GA-cal
No full textGA-cal is a Fortran software for automatically calibrating constitutive laws using Genetic Algorithms (GA) optimization. The proposed approach sets the calibration problem as a regression, and the GA optimization is used to adjust the model parameters so that a numerical model matches experimental data. Currently, the code allows the calibration of the Sand Hypoplastic law (SH), proposed by von Wolffersdorff, with the oedometer (OE) and triaxial drained (TD) test data
GA-Fuzzy PID control simulation waveform diagram.
No full textAs is well known, the metal annealing process has the characteristics of heat concentration and rapid heating. Traditional vacuum annealing furnaces use PID control method, which has problems such as high temperature fluctuation, large overshoot, and long response time during the heating and heating process. Based on this situation, some domestic scholars have adopted fuzzy PID control algorithm in the temperature control of vacuum annealing furnaces. Due to the fact that fuzzy rules are formulated through a large amount of on-site temperature data and experience summary, there is a certain degree of subjectivity, which cannot ensure that each rule is optimal. In response to this drawback, the author combined the technical parameters of vacuum annealing furnace equipment, The fuzzy PID temperature control of the vacuum annealing furnace is optimized using genetic algorithm. Through simulation and comparative analysis, it is concluded that the design of the fuzzy PID vacuum annealing furnace temperature control system based on GA optimization is superior to fuzzy PID and traditional PID control in terms of temperature accuracy, rise time, and overshoot control. Finally, it was verified through offline experiments that the fuzzy PID temperature control system based on GA optimization meets the annealing temperature requirements of metal workpieces and can be applied to the temperature control system of vacuum annealing furnaces.</div
adrien-ga/Simstrat-BSIW: Simstrat v1.3
No full text<p>Simstrat version allowing the use of a filtered wind time series for improved modelling of basin-scale internal waves (BSIWs), as described in the paper gmd-2016-262</p>
GA-LNS Optimization for Helicopter Rescue Dispatch
No full textAviation emergency rescue has become one of the most effective means for natural disaster relief due to its flexible and timely characteristics. A reasonable emergency dispatch plan can guarantee the effective implementation of all the rescue measures. Most of previous studies in this area focused on the scheduling and routing but ignored the impact of the specific rescue process, for example the fuel consumption of various helicopters. In this paper, a multi-helicopter-multi-trip Aviation Rescue Routing Problem (ARRP) is analysed which covers the whole rescue process. In addition, a time-domain procedural simulation model is built which can consider different helicopters, refueling or not, various resource locations, multiple disaster sites and other operation factors. Based on that, a Genetic Algorithm (GA) hybridized Large Neighborhood Search (LNS) algorithm (GA-LNS) is proposed for optimization. In ARRP, single search algorithm may lead to the local optimum due to complexity. In contrast, the distance greedy strategy and the load ratio strategy are combined in GA-LNS which can fix the local optimum problem. More specifically, based on the helicopter-tagged-task-sequenced chromosome, the single-point crossover operator is used in GA and then, the worst removal strategy and the first/last insertion strategy are adopted in LNS. Finally, the numerical experiments are exercised to verify the effectiveness of the proposed GA-LNS algorithm which is compared with three traditional basic heuristic algorithms and a stateof-the-art memetic algorithm.</p
Ga-Substituted Nanoscale HZSM‑5 in Methanol Aromatization: The Cooperative Action of the Brønsted Acid and the Extra-Framework Ga Species
No full textA series of nanosized [Al]-, [Ga,
Al]-, and [Ga]-HZSM-5 catalysts with a fixed Si-to-M3+ ratio
(M = Al or Ga) was synthesized by a seed-induced crystallization method.
In order to reveal the catalytic nature of the extra-framework Ga
species, an acid treatment was applied to selectively extract Lewis
acidic amorphous Ga cations of as-synthesized catalysts. A comparative
evaluation of freshly prepared and acid-treated catalysts in methanol
conversion to aromatics showed the dehydrogenative nature of the extra-framework
Ga species, which is essential in the enhancement of aromatics. Among
tested catalysts, [Ga, Al]-HZSM-5 with a low extra-framework Ga-to-Brønsted
acid ratio (0.06) was the most effective. The efficacy is due to the
contact synergy of the extra-framework Ga species and the Brønsted
acid, by which aromatics originated from the dual-cycle mechanism
of methanol conversion can be accelerated
GA-LNS Optimization for Helicopter Rescue Dispatch
No full textAviation emergency rescue has become one of the most effective means for natural disaster relief due to its flexible and timely characteristics. A reasonable emergency dispatch plan can guarantee the effective implementation of all the rescue measures. Most of previous studies in this area focused on the scheduling and routing but ignored the impact of the specific rescue process, for example the fuel consumption of various helicopters. In this paper, a multi-helicopter-multi-trip Aviation Rescue Routing Problem (ARRP) is analysed which covers the whole rescue process. In addition, a time-domain procedural simulation model is built which can consider different helicopters, refueling or not, various resource locations, multiple disaster sites and other operation factors. Based on that, a Genetic Algorithm (GA) hybridized Large Neighborhood Search (LNS) algorithm (GA-LNS) is proposed for optimization. In ARRP, single search algorithm may lead to the local optimum due to complexity. In contrast, the distance greedy strategy and the load ratio strategy are combined in GA-LNS which can fix the local optimum problem. More specifically, based on the helicopter-tagged-task-sequenced chromosome, the single-point crossover operator is used in GA and then, the worst removal strategy and the first/last insertion strategy are adopted in LNS. Finally, the numerical experiments are exercised to verify the effectiveness of the proposed GA-LNS algorithm which is compared with three traditional basic heuristic algorithms and a stateof-the-art memetic algorithm.</p
Desenvolvimentos de estruturas muitiferroicas de filmes finos de ligas Ni-Mn-Ga e PMN-PT
Full text linkMestrado em Ciência e Engenharia de MateriaisLigas de forma ferromagnética em sistemas Ni-Mn-Ga são uma classe recente de
materiais activos que podem gerar deformações de até 10% induzidas por um campo
magnético por um rearranjo de maclas. Esta e outras propriedades físicas destas ligas
têm importância tecnológica. Este trabalho investiga as propriedades de filmes finos
de ligas de Ni-Mn-Ga sobre diferentes substratos, incluindo substratos activos
(piezeléctricos). Para estudar as propriedades de filmes finos da liga, heteroestruturas
sob a forma de Ni-Mn-Ga/substrato foram produzidas por RF sputtering com
magnetrão utilizando temperaturas de deposição de 3200C, 3700C, 4000C sobre
substratos de Al2O3, MgO, SrTiO3 e PMN-PT. A influência da temperatura do
substrato durante a deposição nas propriedades estruturais e magnéticas de filmes finos
foi estudada. Além disso, o acoplamento magnetoeléctrico entre Ni-Mn-Ga como filme
fino material ferromagnético e PMN-PT como material piezoeléctrico foi investigada.
O efeito magnetoeléctrico foi investigado apenas em filmes depositados a temperatura
do substrato de 3700C e 4000C. As propriedades estruturais foram estudadas por
difração de raios-X, as propriedades magnéticas foram investigadas por VSM, SQUID,
e MFM, e o efeito magnetoeléctrico foi estudado por técnica lock-in. A medida
estrutural mostrou que os filmes depositados são parcialmente cristalinos e o grau de
cristalinidade aumenta como o aumento da temperatura do substrato. Fases austenita e
martensita foram observadas nesses filmes. Os resultados da medição magnética
mostram que todos os filmes depositados exibem comportamento ferromagnético e o
comportamento ferromagnético é favorecido com o aumento da temperatura do
substrato. Todos os filmes depositados na temperatura do substrato de 400ºC
apresentam temperaturas dev Curie acima da temperatura ambiente: 337K para Ni-Mn-
Ga/PMN-PT, 345K para Ni-Mn-Ga/STO e 348K para Ni-Mn-Ga/Al2O3. Nenhuma
evidência separada de temperatura de transição estrutural foi observada para nos
filmes. Os resultados das medições magnetoeléctricas mostram que as heteroestruturas
multiferróicas Ni-Mn-Ga/PMN-PT apresentam efeito magnetoelétrico. O valor
máximo medido para a tensão magnetoeléctrica induzida para filmes depositados à
temperatura do substrato de 3700C e 4000C são 3.16mV/cmOe e 3.02mV/cmOe,
respectivamente.Ferromagnetic shape memory alloys (FSMAs) in Ni-Mn-Ga systems are a
recent class of active materials that can generate large magnetic field induced
strains up to 10% by twin rearrangement. This and other physical properties
these alloys have many technological importance. This work investigates the
properties of Ni-Mn-Ga alloy thin films on different substrates including active
substrate (piezoelectric). To study the properties of thin films of the alloy, the
heterostructures in the form of Ni-Mn-Ga/substrate were produced by RF
magnetron deposition system using substrate deposition temperatures of
3200C, 3700C, and 4000C, where the substrates used were Al2O3, MgO, SrTiO3
and PMN-PT. The influences of deposition substrate temperature on structural
and magnetic properties of sputtered thin films on the aforementioned
substrates were studied. Moreover, magnetoelectric coupling between Ni-Mn-
Ga thin film as ferromagnetic material and PMN-PT as piezoelectric material
was investigated. The magnetoelectric effect was investigated only on films
deposited at substrate temperature of 3700C and 4000C. The structural
properties were studied by x-ray diffraction, magnetic properties were
investigated by VSM, SQUID, and MFM, and the magnetoelectric effect was
studied by lock-in technique. The structural measurement has shown that asdeposited
films are partially crystalline and degree of crystallinity increases as
substrate temperature increase. Austenite and martensite phases have been
observed in these films. The magnetic measurement results show that all films
as-deposited display ferromagnetic behaviour and ferromagnetic behaviour
improvements are observed as substrate temperature increases. All films
deposited at substrate temperature of 4000C exhibit Curie temperatures above
room temperature which are 337K for Ni-Mn-Ga/PMN-PT, 345K for Ni-Mn-
Ga/STO, 348K for Ni-Mn-Ga/Al2O3. No separate signature of structural
transition temperature was observed for all these films. The magnetoelectric
measurement results show that a heterostructure of Ni-Mn-Ga/PMN-PT
multiferroic exhibit magnetoelectric effect. The measured maximum induced
magnetoelectric voltage for films deposited at substrate temperature of 3700C
and 4000C are 3.16mV/cmOe and 3.02mV/cmOe, respectively
Ga(AAZTA) és Ga(CyAAZTA) komplexek szerkezeti tulajdonságainak tanulmányozása kvantumkémiai módszerekkel
No full textGa(AAZTA) komplexek szerkezeti vizsgálata. Kísérletes eredmények elméleti számításokkal való alátámasztása.gjVegyészmérnökBSc/B
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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