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Multi-objective optimization of double-layer microchannel heat sink with trapezoidal cross-sections based on computational fluid dynamics

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INTERNATIONAL JOURNAL OF THERMAL SCIENCES 2025年 214卷

作者： Mohammadi, Rafat dadras, vahid Arak Univ Dept Mech Engn Arak Iran

This study presents a multi-objective optimization of a trapezoidal double-layer microchannel heat sink (TDLMCHS) to minimize both thermal resistance and pumping power. A three-dimensional fluid-solid conjugate heat transfer model, coupled with a multi-objective genetic algorithm, was employed. The optimization considered five design variables, including the flow rate ratio between the upper and lower channels and four geometric parameters related to the channel cross-sections. A parametric study explored the design space, and response surface approximation was applied to improve computational efficiency. The results showed that the optimized TDL-MCHS achieved up to a 42 % reduction in thermal resistance, though at the cost of a significant increase in pumping power. Conversely, minimizing pumping power by 42 % led to a 4 % reduction in thermal resistance. The Pareto-optimal front highlights the trade-offs between thermal performance and energy consumption, providing valuable insights for the efficient design of TDL-MCHSs in electronic cooling applications.

关键词： Double-layer microchannel heat sink Trapezoidal cross-section Multi-objective genetic algorithm Thermal resistance Pumping power Electronic cooling Thermal management

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Sliding mode control for uncertain new chaotic dynamical system

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CHAOS SOLITONS & FRACTALS 2009年第4期41卷 1857-1862页

作者： dadras, Sara Momeni, Hamid Reza Majd, vahid Johari Tarbiat Modares Univ Dept Elect Engn Automat & Instruments Lab Tehran Iran Tarbiat Modares Univ Dept Elect Engn Intelligent Control Syst Lab Tehran Iran

This paper proposes a sliding mode control strategy for a new uncertain chaotic dynamical system (Liu system). Using the sliding mode control technique and based on Lyapunov stability theory, a sliding surface is determined and a robust control law is established which stabilizes the uncertain chaotic system. The chattering phenomenon, which is inherent in conventional switching-type sliding controllers, due to this control law is very small and is clamped quickly. An illustrative simulation result is given to demonstrate the effectiveness of the proposed sliding mode control design. (C) 2008 Elsevier Ltd. All rights reserved.

关键词： SLIDING mode control CHAOS theory DYNAMICS LYAPUNOV stability ROBUST control SWITCHING theory SIMULATION methods & models

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Pressure effects on the carbon nano-tube embedded Y-123 superconductors

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PHYSICA B-CONDENSED MATTER 2016年 487卷 42-46页

作者： dadras, Sedigheh Manivannan, Nallayian Daadmehr, vahid Rezakhani, Ali Tayefeh Kim, Kee Hoon Alzahra Univ Dept Phys Tehran *** Iran Seoul Natl Univ Dept Phys & Astron CeNSCMR Seoul 151747 South Korea Seoul Natl Univ Dept Phys & Astron FPRD Seoul 151747 South Korea Sharif Univ Technol Dept Phys Tehran Iran

It has been known that applying pressure and doping carbon nano-tubes (CNTs) can each affect the behavior of high temperature superconductors. Here, bridging these two effects in order to see how they can interplay, we investigate how the dc resistivity varies in both pure and CNT-doped polycrystalline YBa2Cu3O7-delta (Y-123) compounds under hydrostatic pressure. We demonstrate that the broadening of the resistivity transition in the CNT-doped samples (of 0.7 wt%) is smaller than the undoped samples. In addition, by increasing applied pressure, the doped samples exhibit a higher rate of the increase of the transition temperatures T-c(on) and T-c(mid) than the undoped samples. Interestingly as well, under applied pressure of 1.5 GPa, it is found that T-c(on) for the doped samples (99.39 K) is relatively higher than in the undoped samples (96.88 K). The doped samples also show more robustness versus applied pressure in the sense that they have smaller variations of resistivity. In particular, we observed that the increase rate of the normal resistivity in the CNT-doped samples is nearly four times smaller than the undoped samples. This may be a manifestation of relative robustness of the doped samples against fractures of the links between grains. These observations, overall, may suggest that the CNT doping, due to unique mechanical characteristics of CNTs, can enhance superconductivity properties of Y-123 superconductors under applied pressure. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Hydrostatic pressure effects Superconductivity Y-123 CNT doping Transition temperature Resistivity

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Control of Uncertain Butterfly-Shaped Chaotic System: Sliding-mode Approach

Control of Uncertain Butterfly-Shaped Chaotic System: Slidin...

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International Conference on Control, Automation and Systems

作者： dadras, Sara Momeni, Hamid Reza Majd, vahid Johari Tarbiat Modares Univ Dept Elect Engn Tehran Iran

ISBN: (纸本)9788995003893

A sliding mode control scheme for an uncertain Butterfly-shaped chaotic dynamical system is proposes in this paper. A sliding surface is determined according to the sliding mode control technique and the control law is established. Stability of the sliding control law is determined using Lyapunov stability theory. The chattering phenomenon, which deteriorates the system performance and may cause unforeseen instabilities, is attenuated due to this control law. The effectiveness of the presented sliding mode control design is confirmed through numerical simulations.

关键词： Chaos system Sliding mode control Chattering phenomenon Lyapunov stability

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Fuzzy Surface-Based Control for Uncertain Unified Chaotic Systems

Fuzzy Surface-Based Control for Uncertain Unified Chaotic Sy...

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International Conference on Control, Automation and Systems

作者： dadras, Sara Momeni, Hamid Reza Majd, vahid Johari Tarbiat Modares Univ Dept Elect Engn Tehran Iran

ISBN: (纸本)9788995003893

This paper proposes a fuzzy sliding mode control strategy for an uncertain unified chaotic system with input nonlinearity. Using the sliding mode control technique, a sliding surface is determined and the control law is established. A fuzzy system is used instead of sign function in the sliding mode control to reduce the chattering phenomenon on the sliding surface. Based on Lyapunov stability theory, stability of the fuzzy sliding control law is determined. Chattering in the system with nonlinearity input is also damped due to this control law. The illustrative simulation results are given to demonstrate the effectiveness of the proposed fuzzy sliding mode control design.

关键词： Chaos system Sliding mode control Fuzzy control Chattering phenomenon

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Photobiomodulation improved stereological parameters and sperm analysis factors in streptozotocin-induced type 1 diabetes mellitus

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JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2018年第0期186卷 81-87页

作者： dadras, Sara Abdollahifar, Mohammad-Amin Nazarian, Hamid Ghoreishi, Seyed Kamran Fallahnezhad, Somaye Naserzadeh, Parvaneh Jajarmi, vahid Chien, Sufan Bayat, Mohammad Shahid Beheshti Univ Med Sci Dept Biol & Anat Sci Tehran Iran Univ Qom Dept Stat Qom Iran Shahid Beheshti Univ Med Sci Sch Pharm Dept Pharmacol & Toxicol Tehran Iran Shahid Beheshti Univ Med Sci Sch Adv Technol Med Dept Biotechnol Tehran Iran Univ Louisville Price Inst Surg Res Louisville KY 40292 USA Noveratech LLC Louisville Louisville KY USA

The aim of this study was to evaluate the effect of photobiomodulation (PBM) on testicular tissues and fresh sperm analysis factors in streptozotocin (STZ)-induced type one diabetes mellitus (T1DM) mice. T1DM was induced in 15 male Syrian mice by injection of 200 mg/kg STZ. After one month, mice were divided randomly into three groups, harboring 5 mice each: 1, control group;2, first laser group (890 nm, 80 Hz, 0.03 J/cm(2)) and 3, second laser group (0.2 J/cm(2)). Then the mice were euthanized and testicles were dissected for stereological studies, and both epididymis and vas deferens were removed for fresh sperm analysis. Data were analyzed by statistical methods. A significant increase was observed in the Sertoli cell count in both PBM groups, compared to the control group. In addition, the second PBM group shows a significant increase in the Sertoli cell count, compared to the first PBM group. Both PBM groups show significant increase in the Leydig cell count, compared to the control group. There were significant increases of the length in the seminiferous tubules in both PBM groups, compared to the control group. In addition, the second PBM group showed a significant increase of the length in the seminiferous tubules, compared to the first PBM group. The second PBM group showed a significant increase in the sperm count, compared to the control, and first PBM groups. The first PBM group showed a significant increase in sperm count, compared to the control group. The sperm motility and count were significantly increased in the second PBM group, compared to the control and first PBM groups. The sperm motility was significantly increased in the first PBM group, compared to the control group. PBM with 0.2 J/cm(2) and 0.03 J/cm(2) energy densities significantly improved the stereological parameters and fresh sperm analysis factors, compared to the control group in STZ-induced T1DM in mice. Moreover, the PBM with 0.2 J/cm(2) energy density was statistically more effec

关键词： Photobiomodulation Diabetes mellitus Testicle Stereological parameters Sperm analysis factors Low-level laser therapy

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Demographic, clinical, and virological characteristics of patients with a laboratory-confirmed diagnosis of influenza during three consecutive seasons, 2015/2016-2017/18, in the Islamic Republic of Iran

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JOURNAL OF CLINICAL VIROLOGY 2020年 124卷 104281-104281页

作者： Nateghian, Alireza Gouya, Mohammad Mehdi Nabavi, Mahmood Soltani, Hanieh Mousavi, Seyed vahid Agah, Elmira Erfani, Hosein Parchami, Peiman dadras, Mohammadnasr Robinson, Joan L. Iran Univ Med Sci Tehran Iran Minist Hlth & Med Educ Tehran Iran Univ Tehran Med Sci Students Sci Res Ctr Tehran Iran USERN NeuroImmunol Res Assoc NIRA Tehran Iran Univ Alberta Edmonton AB Canada

Background: There are minimal data on the differences in demographics, clinical presentations and outcomes for patients with different types and sub-types of influenza in the Middle East. Objectives: To use population-based data from Iran to investigate factors associated with unfavorable disease outcome. Study design: Clinical data were compiled from the Iranian Ministry of Health for patients of all ages who fulfilled the severe acute respiratory infections (SARI) definition according to World Health Organization criteriatested for any reason and found to have and had laboratory proven influenza September 21, 2015 through March 20, 2018. Pulmonary, cardiac, renal, hematologic and neurologic complications were recorded. Results were compared by type, age, gender and health status. Multivariate analysis was used to analyze risk factors for complications and death. Results: Of 11,080 enrolled patients, 10,046 (90.7 %) were inpatients, 2254 (20.4 %) were children, 8403 (75.8 %) had influenza A, 2599 (23.5 %) had influenza B, and 78 (0.7 %) had unidentified types. Fever was less common in older patients (OR 0.99;95 % CI 0.98-0.99, p < 0.001 and in those with comorbidity (OR 0.87;95 % CI 0.77-0.97, p = 0.013). Although the rate of complications was lower with A(H1N1) pdm09 influenza than with A(H3N2) infection (12.8 % versus 15.6 %, p = 0.001), the mortality rate was higher (7.0 % versus 3.0 %, p < 0.001). Complications occurred more often during late versus early influenza season (OR 1.22;95 % CI 1.08-1.37, p = 0.002). Patients with type B influenza (OR 0.85;95 % CI 0.74-0.98, p = 0.025), or who presented with sore throat (OR 0.74;95 % CI 0.65-0.84, p < 0.001) were less likely to develop complications. The risk of developing complications was increased in patients who had chronic heart disease (OR 1.51;95 % CI 1.29-1.76, p < 0.001), chronic pulmonary disease (OR 1.62;95 % CI 1.37-1.91, p < 0.001), diabetes (OR 1.24;95 % CI 1.03-1.50, p = 022), or epilepsy (OR 1.55;95 %

关键词： Influenza Clinical presentation Complications Demographics Influenza subtype

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Fuzzy surface-based control for uncertain unified chaotic systems

Fuzzy surface-based control for uncertain unified chaotic sy...

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International Conference on Control, Automation and Systems ( ICCAS)

作者： Sara dadras Hamid Reza Momeni vahid Johari Majd Department of Electrical Engineering Tarbiat Modares University of Technology Tehran Iran

关键词： Fuzzy control Fuzzy systems Control systems Chaos Sliding mode control Chaotic communication Nonlinear control systems Fuzzy logic Uncertainty Automatic control

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Control of uncertain butterfly-shaped chaotic system: Sliding-mode approach

Control of uncertain butterfly-shaped chaotic system: Slidin...

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International Conference on Control, Automation and Systems ( ICCAS)

作者： Sara dadras Hamid Reza Momeni vahid Johari Majd Department of Electrical Engineering Tarbiat Modares University of Technology Tehran Iran

A sliding mode control scheme for an uncertain butterfly-shaped chaotic dynamical system is proposes in this paper. A sliding surface is determined according to the sliding mode control technique and the control law is established. Stability of the sliding control law is determined using Lyapunov stability theory. The chattering phenomenon, which deteriorates the system performance and may cause unforeseen instabilities, is attenuated due to this control law. The effectiveness of the presented sliding mode control design is confirmed through numerical simulations.

关键词： Sliding mode control Control systems Chaos Nonlinear control systems Uncertainty Automatic control Lyapunov method Systems engineering and theory Adaptive control Nonlinear dynamical systems

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Global, regional, and national burden of epilepsy, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

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The Lancet Public Health 2025年第3期10卷 e203-e227页

作者： Feigin, Valery L Vos, Theo Nair, Balakrishnan Sukumaran Hay, Simon I Abate, Yohannes Habtegiorgis Abd Al Magied, Abdallah H A Abd ElHafeez, Samar Abdelkader, Atef Abdollahifar, Mohammad-Amin Abdullahi, Auwal Aboagye, Richard Gyan Abreu, Lucas Guimarães Abu Rumeileh, Samir Abualruz, Hasan Aburuz, Salahdein Abu-Zaid, Ahmed Addo, Isaac Yeboah Adedoyin, Rufus Adesoji Adepoju, Abiola Victor Afzal, Muhammad Sohail Afzal, Saira Ahmad, Aqeel Ahmad, Sajjad Ahmad, Tauseef Ahmadi, Ali Ahmadzade, Amir Mahmoud Ahmed, Ayman Ahmed, Haroon Ahmed, Mehrunnisha Sharif Ahmed, Muktar Beshir Al Awaidy, Salah Al Omari, Omar Al-Ajlouni, Yazan Albashtawy, Mohammed Al-Fatly, Bassam Algammal, Abdelazeem M Ali, Abid Ali, Mohammed Usman Ali, Syed Shujait Ali, Waad Alif, Sheikh Mohammad Almazan, Joseph Uy Alshahrani, Najim Z Altaf, Awais Al-Wardat, Mohammad Al-Worafi, Yaser Mohammed Aly, Hany Alzoubi, Karem H Amiri, Sohrab Ancuceanu, Robert Angappan, Dhanalakshmi Ansari, Mohammed Tahir Anvari, Saeid Anyasodor, Anayochukwu Edward Arabloo, Jalal Arafat, Mosab Aravkin, Aleksandr Y Aregawi, Brhane Berhe Aremu, Abdulfatai Atout, Maha Moh'd Wahbi Atreya, Alok Aujayeb, Avinash Aychiluhm, Setognal Birara Aziz, Shahkaar Azzam, Ahmed Y Badiye, Ashish D Bai, Ruhai Baig, Atif Amin Bakkannavar, Shankar M Bandyopadhyay, Soham Banerjee, Indrajit Bardhan, Mainak Barker-Collo, Suzanne Lyn Barrow, Amadou Basharat, Zarrin Bashiri, Azadeh Basiru, Afisu Bastan, Mohammad-Mahdi Batchu, Sai Behnam, Babak Bejarano Ramirez, Diana Fernanda Bemanalizadeh, Maryam Beyene, Kebede A Bhagat, Devidas S Bhagavathula, Akshaya Srikanth Bhaskar, Sonu Bhat, Ajay Nagesh Bhatti, Gurjit Kaur Bhatti, Jasvinder Singh Bhuiyan, Mohiuddin Ahmed Bhuyan, Soumitra S Bilgin, Cem Bisulli, Francesca Boloor, Archith Boppana, Sri Harsha Bouaoud, Souad Bustanji, Yasser Çakmak Barsbay, Mehtap Carvalho, Felix Castaldelli-Maia, Joao Mauricio Chandika, Rama Mohan Chattu, Vijay Kumar Chaudhary, Anis Ahmad Ching, Patrick R Chopra, Hitesh Chu, Dinh-Toi Chu, Hongyuan Cortese, Samuele Cortesi, Paolo Angelo Auckland Univ Technol Auckland 0627 New Zealand

Background: Epilepsy is one of the most common serious neurological disorders and affects individuals of all ages across the globe. The aim of this study is to provide estimates of the epilepsy burden on the global, regional, and national levels for 1990–2021. Methods: Using well established Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) methodology, we quantified the prevalence of active idiopathic (epilepsy of genetic or unknown origin) and secondary epilepsy (epilepsy due to an underlying abnormality of the brain structure or chemistry), as well as incidence, death, and disability-adjusted life-years (DALYs) by age, sex, and location (globally, 21 GBD regions and seven super-regions, World Bank country income levels, Socio-demographic Index [SDI], and 204 countries) and their trends from 1990 to 2021. Vital registrations and verbal autopsies provided information about deaths, and data on the prevalence and severity of epilepsy, largely came from population representative surveys. All estimates were calculated with 95% uncertainty intervals (UIs). Findings: In 2021, there were 51·7 million (95% UI 44·9–58·9) people with epilepsy (idiopathic and secondary combined) globally, with an age-standardised prevalence of 658 per 100 000 (569–748). Idiopathic epilepsy had an age-standardised prevalence of 307 per 100 000 (235–389) globally, with 24·2 million (18·5–30·7) prevalent cases, and secondary epilepsy had a global age-standardised prevalence of 350 per 100 000 (322–380). In 2021, 0·7% of the population had active epilepsy (0·3% attributed to idiopathic epilepsy and 0·4% to secondary epilepsy), and the age-standardised global prevalence of epilepsy from idiopathic and secondary epilepsy combined increased from 1990 to 2021 by 10·8% (1·1–21·3), mainly due to corresponding changes in secondary epilepsy. However, age-standardised death and DALY rates of idiopathic epilepsy reduced from 1990 to 2021 (decline of 15·8% [8·8–22·8] and 14·5% [4·2–24·2], re

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