Hasil untuk "Engineering"

Eiki Yamaguchi

John Towns, T. Cockerill, M. Dahan et al.

S. Foucart, H. Rauhut

J. Schindelin, Ignacio Arganda-Carreras, E. Frise et al.

E. Gamma, Richard Helm, Ralph E. Johnson et al.

J. Nocedal, Stephen J. Wright

Numerical Optimization presents a comprehensive and up-to-date description of the most effective methods in continuous optimization. It responds to the growing interest in optimization in engineering, science, and business by focusing on the methods that are best suited to practical problems. For this new edition the book has been thoroughly updated throughout. There are new chapters on nonlinear interior methods and derivative-free methods for optimization, both of which are used widely in practice and the focus of much current research. Because of the emphasis on practical methods, as well as the extensive illustrations and exercises, the book is accessible to a wide audience. It can be used as a graduate text in engineering, operations research, mathematics, computer science, and business. It also serves as a handbook for researchers and practitioners in the field. The authors have strived to produce a text that is pleasant to read, informative, and rigorous - one that reveals both the beautiful nature of the discipline and its practical side.

M. Abramowitz, I. Stegun, R. H. Romer

S. Haykin

Panagiotis D. Christofides, R. Scattolini, David Mu˜noz de la Pe˜na d et al.

W. Mendenhall, T. Sincich

H. Vliet

Dipankar Dasgupta, Zbigniew Michalewicz

LIN Yongfeng, CHENG Zhen, LIU Wenmei, ZOU Zehua, LIU Hong, LIU Guangming, LIU Qingmei

In this study, the physicochemical properties of polysaccharides from Houttuynia cordata Thunb. fermented with Lactiplantibacillus plantarum HM6008 (FHCTP) were determined, and the antiallergic activity was evaluated using rat basophilic leukemia (RBL)-2H3 cells. The results showed that fermentation increased the ratio of mannose to sulfate in FHCTP. Compared with H. cordata Thunb. polysaccharides (HCTP), the particle size of FHCTP decreased by 26.67%, and its stability in aqueous solution increased. The inhibition rate of FHCTP on the degranulation of RBL-2H3 cells was significantly higher than that of HCTP, (82.79 ± 5.19)% versus (53.75 ± 1.95)%. After FHCTP intervention, the expression of fragment crystallizable epsilon receptor I (FcεRI) was significantly down-regulated, and the average fluorescence intensity decreased from 2 458.00 ± 7.50 to 1 495.00 ± 28.50. Both FHCTP and HCTP effectively inhibited the isomerization of cytoskeletal proteins and the increase of intracellular calcium ion concentration. In addition, in the mouse passive cutaneous anaphylaxis assay, FHCTP showed a more significant inhibitory effect on dye extravasation in mouse ears, indicating stronger antiallergic activity. In conclusion, FHCTP has better stabilizing effect on mast cells and effectively alleviates mast cell-mediated passive cutaneous anaphylaxis in mice. The results of this research are expected to promote the development and application of antiallergic products from edible and medicinal materials.

Lijo Jacob Varghese, Suma Sira Jacob, Jaisiva Selvaraj et al.

Abstract This article describes a method for improving power grid voltage profiles by more effectively regulating reactive power through the integration of hybrid renewable energy systems (HRES) in smart grids. The unpredictable nature of renewable energy sources RES, such as wind turbines and solar systems, causes an unstable voltage profile throughout the grid, underscoring the problem of voltage fluctuation in power grids. This article proposes DSTATCOM, a reactive power adjustment device, to address these voltage fluctuations and provide the grid with the required var. DSTATCOM assists in preserving voltage stability by consistently lowering the voltage drop, which guarantees an increase in active power flow. Therefore, the overall voltage profile throughout the electrical grid gets improved. Convolutional neural networks (CNN) with bidirectional long short-term memory (BiLSTM) combined to form the proposed solution, which controls and maximizes DSTATCOM performance. These advanced artificial intelligence (AI) methods helps in dynamic reactive power management, improving the grid’s voltage profile and DSTATCOM’s performance. In smart grid situations, this method works well for real-time voltage regulation since CNNs are employed for feature extraction and BiLSTM helps capture temporal dependencies in the grid’s power behavior. The CNN-BiLSTM network’s weights are also adjusted using an adaptive parrot optimizer (APO). The proposed approach was implemented using the MATLAB/Simulink environment, and three different scenarios were used to assess its performance. Simulation results confirm that the method achieved up to 33.4% loss reduction, improved voltage stability index (VSI) to 1.02 p.u, minimized total harmonic distortion (THD) below 1.7%, and cut settling time to 0.075 s. The hybrid PV/wind setup ensured superior voltage stability, while the model attained high prediction accuracy with an R2 of 0.9672 and RMSE of 3.0094. By controlling reactive power balance, the created system assures grid stability, improves the voltage profile, and reduces power loss.

David Bujdos, Zachary Kuzel, Adam Wood

Pyrolyzed carbon electrodes (PCEs) can provide sustainable alternatives in electric devices, but it is difficult to control their surface geometries during their semi-destructive fabrication procedure. Impressive contributions have been made to the field of PCE fabrication in terms of the nanoscale, functionalization, and separation applications; however, further progress towards an emphasis on a sustainable life cycle is the next step forward. Here, we propose two new methodologies for creating sustainable PCEs: stamping, where a user-designed, 3D printed electrode precursor (EP) imparts a shape on an organic material, and reconstitution, where the same EP acts as a mould as a mixture of agitated organic material and water dries to leave behind a rigid shape. Both methods allow for the reuse of the EP and the upcycling of biologically derived waste products as a pyrolytic input, and they do not require chemical modification. A comparison of the two methodologies is discussed as surface features of PCEs scale by a factor of 0.78 during the reconstitution process and by a factor of 0.68 during the stamping process. These PCEs maintain defined structures on the micro-scale and demonstrate previously unachievable resolution to the naked eye prior to these two novel pathways.

Ting Feng, Wenfeng Chen, Aja McDonagh et al.

Luma F. Ali, Hussein Togun, Abdellatif M. Sadeq

Practical applications such as solar power energy systems, electronic cooling, and the convective drying of vented enclosures require continuous developments to enhance fluid and heat flow. Numerous studies have investigated the enhancement of heat transfer in L-formed vented cavities by inserting heat-generating components, filling the cavity with nanofluids, providing an inner rotating cylinder and a phase-change packed system, etc. Contemporary work has examined the thermal performance of L-shaped porous vented enclosures, which can be augmented by using metal foam, using nanofluids as a saturated fluid, and increasing the wall surface area by corrugating the cavity’s heating wall. These features are not discussed in published articles, and their exploration can be considered a novelty point in this work. In this study, a vented cavity was occupied by a copper metal foam with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mi>P</mi><mi>I</mi><mo>=</mo><mn>10</mn></mrow></semantics></math></inline-formula> and saturated with a copper–water nanofluid. The cavity walls were well insulated except for the left wall, which was kept at a hot isothermal temperature and was either non-corrugated or corrugated with rectangular waves. The Darcy–Brinkman–Forchheimer model and local thermal non-equilibrium models were adopted in momentum and energy-governing equations and solved numerically by utilizing commercial software. The influences of various effective parameters, including the Reynolds number (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>20</mn><mo>≤</mo><mi>R</mi><mi>e</mi><mo>≤</mo><mn>1000</mn></mrow></semantics></math></inline-formula>), the nanoparticle volume fraction (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0</mn><mo>%</mo><mo>≤</mo><mi>φ</mi><mo>≤</mo><mn>20</mn><mo>%</mo></mrow></semantics></math></inline-formula>), the inflow and outflow vent aspect ratios (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.1</mn><mo>≤</mo><mrow><mrow><mi>D</mi></mrow><mo>/</mo><mrow><mi>H</mi></mrow></mrow><mo>≤</mo><mn>0.4</mn></mrow></semantics></math></inline-formula>), the rectangular wave corrugation number (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>N</mi><mo>=</mo><mn>5</mn></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>N</mi><mo>=</mo><mn>10</mn></mrow></semantics></math></inline-formula>), and the corrugation dimension ratio (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>C</mi><mi>R</mi><mo>=</mo><mn>1</mn></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>C</mi><mi>R</mi><mo>=</mo><mn>0.5</mn></mrow></semantics></math></inline-formula>) were determined. The results indicate that the flow field and heat transfer were affected mainly by variations in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>R</mi><mi>e</mi></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mrow><mi>D</mi></mrow><mo>/</mo><mrow><mi>H</mi></mrow></mrow></mrow></semantics></math></inline-formula>, and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>φ</mi></mrow></semantics></math></inline-formula> for a non-corrugated left wall; they were additionally influenced by <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>N</mi></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>C</mi><mi>R</mi></mrow></semantics></math></inline-formula> when the wall was corrugated. The fluid- and solid-phase temperatures of the metal foam increased with an increase in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>R</mi><mi>e</mi></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mrow><mi>D</mi></mrow><mo>/</mo><mrow><mi>H</mi></mrow></mrow></mrow></semantics></math></inline-formula>. The fluid-phase Nusselt number near the hot left sidewall increased with an increase in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>φ</mi></mrow></semantics></math></inline-formula> by <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mfenced separators="|"><mrow><mn>25</mn><mo>–</mo><mn>60</mn></mrow></mfenced><mo>%</mo></mrow></semantics></math></inline-formula>, while the solid-phase Nusselt number decreased by <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mfenced separators="|"><mrow><mn>10</mn><mo>–</mo><mn>30</mn></mrow></mfenced><mo>%</mo></mrow></semantics></math></inline-formula>, and these numbers rose by around <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>3.5</mn></mrow></semantics></math></inline-formula> times when the Reynolds number increased from <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>20</mn></mrow></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1000</mn></mrow></semantics></math></inline-formula>. For the corrugated hot wall, the Nusselt numbers of the two metal foam phases increased with an increase in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>R</mi><mi>e</mi></mrow></semantics></math></inline-formula> and decreased with an increase in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mrow><mi>D</mi></mrow><mo>/</mo><mrow><mi>H</mi></mrow></mrow></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>C</mi><mi>R</mi></mrow></semantics></math></inline-formula>, or <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>N</mi></mrow></semantics></math></inline-formula> by <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>10</mn><mo>%</mo></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>19</mn><mo>%</mo></mrow></semantics></math></inline-formula>, and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>37</mn><mo>%</mo></mrow></semantics></math></inline-formula>. The original aspect of this study is its use of a thermal, non-equilibrium, nanofluid-saturated metal foam in a corrugated L-shaped vented cavity. We aimed to investigate the thermal performance of this system in order to reinforce the viability of applying this material in thermal engineering systems.

K. Demarest

L. Brammer

W. Marwood, L. Jain