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Thermomechanical Characterization of Hot Surface Ignition Device Using Phenomenological Heat Flux Model

JOURNAL OF PROPULSION AND POWER 2022年第4期38卷 656-670页

作者： Kang, Sang-Guk Ryu, Je Ir Motily, Austen H. Numkiatsakul, Prapassorn Lee, Tonghun Kriven, Waltraud M. Kim, Kenneth S. Kweon, Chol-Bum M. U.S. Army Research Laboratory Aberdeen Proving Ground MD 21005 Aerospace Engineer Weapons and Materials Research Directorate Postdoctoral Fellow Computational and Information Sciences Directorate University of Illinois at Urbana-Champaign Urbana IL 61801 Graduate Student Department of Mechanical Science and Engineering. Student Member AIAA Graduate Student Department of Materials Science and Engineering Professor Department of Mechanical Science and Engineering. Associate Fellow AIAA Professor Department of Materials Science and Engineering Mechanical Engineer Computational and Information Sciences Directorate. Member AIAA Program Manager Computational and Information Sciences Directorate. Member AIAA.

Modern aircraft compression ignition engines that seek to achieve fuel-flexible operation require ignition-assisting devices to perform reliably. Many military propulsion systems, and unmanned aircraft in particular, can use hot surface energy addition to improve engine performance. An analysis of the thermomechanical stress behavior of hot surface ignition devices is therefore critical to ensure that they can satisfy new operational requirements. In this paper, a phenomenological heat-flux model is proposed to simulate heat generation inside a heating element. Two finite element analysis models are established using the proposed heat-flux model in order to characterize the transient thermomechanical behavior of an ignition assistant: a two-dimensional (2-D) axisymmetric model with an equivalent cylindrical heating element and a three-dimensional (3-D) solid model with realistic heating element geometry. The transient behavior of the ignition assistant is investigated at standard conditions by characterizing the temperature and thermal stress inside the device for various input voltages. The effect of the nonaxisymmetric heating element geometry on the temperature and thermal stress distribution is assessed. Furthermore, the 3-D ignition assistant model is used to analyze the thermomechanical behavior of an ignition device subjected to a combustion event inside a rapid compression machine. Multiple circumferential orientations of the heating element plane relative to the spray axis are investigated. Results demonstrate that the observed maximum principal stress depends significantly on heating element orientation.

关键词： Heat Flux Stress Distribution Heat Generation Unmanned Aerial Vehicle Propulsion System Surface Energy Adaptive Mesh Refinement Fuel Injection CFD Simulation Fracture Toughness

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Mo-terminated edges in two-dimensional molybdenum disulfide for site-specific hydrolysis and DNA cleavage

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materials Today 2025年 86卷 162-171页

作者： Wang, Cong Wu, Menghan Li, Muqing Zhao, Yingcan Zhao, Mingchuang Zhang, Yunhao Bai, Yichao Gao, Jianxiang Wang, Xiaoxia Tian, Xilin Zhang, Han Chang, Liang Zou, Xiaolong Liu, Bilu Kang, Feiyu Terrones, Mauricio Lei, Yu Institute of Materials Research Shenzhen Key Laboratory of Advanced Layered Materials for Value-added Applications Guangdong Provincial Key Laboratory of Thermal Management Engineering and Materials & Center of Double Helix Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen518055 China Institute of Materials Research & Shenzhen Geim Graphene Center Shenzhen Key Laboratory of Advanced Layered Materials for Value-added Applications Tsinghua-Berkeley Shenzhen Institute and Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen518055 China Environmental Science Program Department of Life Sciences Beijing Normal University-Hong Kong Baptist University United International College Guangdong519087 China Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen518055 China Department of Physics Department of Chemistry Department of Materials Sciences Center for 2-Dimensional and Layered Materials The Pennsylvania State University University ParkPA16802 United States International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale Optoelectronics Shenzhen University Shenzhen518060 China

The hydrolysis of DNA serves as the foundational principle for gene engineering that enable precise gene cleavage at the molecular level. This process typically occurs in biological nucleases, which exhibit nucleobase-selective and catalytic hydrolysis capabilities rarely replicated in abiotic nanomaterials. Here, we demonstrate that molybdenum-terminated (Mo-terminated) edges of molybdenum disulfide (MoS2) possess the unique ability to abstract a proton (H+) from water molecules, thereby facilitating catalytic hydrolysis reactions that cleave the phosphodiester bonds in DNA through the action of hydroxide ions. The enhanced proton absorption at Mo-terminated edges of MoS2 significantly reduces the activation energy required for the DNA hydrolysis reaction. Furthermore, the favorable interaction between the Mo-terminated edges and thymine nucleobases promotes both charge transfer and P-O bond cleavage, enabling targeted DNA hydrolysis at 'TTTTTTT' sequences under dark conditions. This discovery underscores the potential of MoS2 as a stable, efficient nanosystem for precise genetic editing, heralding advanced applications in the field of gene engineering. © 2025 The Author(s)

关键词： Activation energy

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Conductive Mof Coating for Suppressing the Mn Dissolution in Limn2o4 Toward Long-Life Lithium-Ion Batteries

SSRN

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SSRN 2024年

作者： Kim, Eunji Lee, Jeongmin Park, Junghyun Nam, Kwan Woo Department of Chemical Engineering and Materials Science Graduate Program in System Health Science and Engineering Ewha Womans University Seoul03760 Korea Republic of

Spinel lithium manganese oxide (LiMn2O4, denoted LMO) is one of the promising cathode materials with non-toxicity, high operating voltage, and low cost. However, structural collapse during battery cycling — caused by Mn dissolution and the Jahn-Teller effect — is a critical disadvantage, reducing cycle retention, particularly at high temperatures. In this investigation, to solve these critical issues of LMO cathode, we introduce Cu3(HITP)2, a conductive two-dimensional (2D) MOF as a surface coating material through a simple process. Coating the conductive 2D Cu3(HITP)2 MOF increases the electrical conductivity and shows the effect of suppressing the dissolution of Mn by enriching the surface of LMO with Mn4+. By suppressing Mn dissolution, structural stability also improves, resulting in offsetting all the inherent problems of LMO. As a result, at 50 °C, CuHITP–LMO exhibits an initial capacity of 98.7 mAh g–1 at 100 mA g–1 and achieved a capacity of 74.5 mAh g–1 after 100 cycles, indicating outstanding cyclability. This research highlights the potential of conductive 2D MOF to improve the electrochemical performances of battery cathode. © 2024, The Authors. All rights reserved.

关键词： Cathodes

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Cr-modified CuAlBe shape memory alloy: Role of microstructure, thermodynamic parameters, superelasticity, dissipated energy and corrosion resistance

Journal of Alloys and Metallurgical Systems

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Journal of Alloys and Metallurgical Systems 2024年 7卷

作者： Silva, David D.S. Candido, Gemierson V.M. Alves, Ricardo F. Dias, Elisabeth A.M.G.S. Oliveira, Danniel F. Federal University of São Carlos Graduate Program in Materials Science and Engineering SP São Carlos13565-905 Brazil Colorado School of Mines George S. Ansell Department of Metallurgical and Materials Engineering GoldenCO80401 United States Federal University of Paraíba Graduate Program in Mechanical Engineering PB João Pessoa58051-900 Brazil Federal University of Rio Grande do Norte Graduate Program in Materials Science and Engineering RN Natal59078-970 Brazil Federal University of Paraíba Graduate Program in Materials Science and Engineering PB João Pessoa58051-900 Brazil

This study reports the effects of Cr addition on the microstructure, superelasticity and corrosion resistance improvement of CuAlBe shape memory alloy. Analysis via structural, morphological, thermal, mechanical and electrochemical characterizations were performed. The analyses revealed austenite as the stable phase at room temperature for all samples. The increase in the Cr content caused a slight increase in the recovery rate and dissipated energy. Electrochemical results demonstrate that a small addition of Cr (0.1–0.3 wt%) increase the corrosion resistance due the decreases of the corrosion current density and increase of the corrosion potential. © 2024 The Authors

关键词： Corrosion resistance

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Creating Mathematical Models to Help Formulate Company Strategies for Knowledge Management System Implementation 9

Creating Mathematical Models to Help Formulate Company Strat...

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9th International Conference on Information Management and Technology, ICIMTech 2024

作者： Sardjono, Wahyu Perdana, Widhilaga Gia Pranata, Dewi Sagita BINUS Graduate Program Master of Information Systems Management Bina Nusantara University Information Systems Management Department Jakarta11480 Indonesia Post Graduate Program of Management Science State University of Jakarta Jakarta13220 Indonesia King's College London Cyber Security Studi Program Faculty of Natural Mathematical & Engineering Sciences Department of Informatics Strands West MinsterWC2R 2LS United Kingdom

ISBN: (纸本)9798350390025

This research aims to build a mathematical model to formulate the problems of implementing knowledge management systems in companies that often face obstacles in achieving the desired objectives and goals. With increasing competition in the business sector, organizations or organizations realize the importance of utilizing the knowledge assets that reside in each individual and organization. If this knowledge can be managed optimally, it can become a competitive advantage for the company due to the emergence of innovative ideas by the concepts of knowledge management theory. By implementing optimal knowledge management (KM), companies can design innovative solutions to improve business operations and increase overall revenue. The factor analysis method will be used to find the determining factors for the success of the implementation of knowledge management systems (KMS) and the regression analysis method will also be used to form a mathematical model of several new factors which are formed as independent variables with the current level of community understanding of KMS as the dependent variable. The research results provide insight into strategies to improve success factors to successfully facilitate KMS implementation. This study contributes to existing knowledge management by providing insight into dynamics that go beyond the technical aspects of KMS, ultimately developing strategies for more effective and efficient utilization of knowledge and organizational growth and supporting competitive advantage for companies. © 2024 IEEE.

关键词： Knowledge organization system (KOS)

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Reusable Hydrogen Storage Tank with Flange Design 10

Reusable Hydrogen Storage Tank with Flange Design

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10th International Conference on Applied System Innovation, ICASI 2024

作者： Li, Yun-Qi Chen, Hsuan-Jung Yang, Hsi-Wen Chen, Chih-Yuan Chang, Shao-Fu Chen, Ssu-Ying Chen, Chien-Chon College of Engineering and Science Ph.D. Program in Materials and Chemical Engineering National United University Miaoli Taiwan Michigan State University Department of Chemistry MI48824 United States National United University Department of Materials Engineering Miaoli Taiwan Graduate Institute of Intellectual Property National Taipei University of Technology Taiwan National United University Department of Energy Engineering Miaoli Taiwan

ISBN: (纸本)9798350394924

For how to store and transport hydrogen, the first thought is to store hydrogen directly in the cylinder. However, this method is not desirable, because generally at least 700 atm high pressure, the hydrogen contained in the cylinder to be useful. Therefore it is very unsafe at such high pressures. In This paper, we design and production of a new generation of solid-state hydrogen storage and discharge container. The goal of 'development of solid-state hydrogen storage technology' is to break through the bottlenecks of hydrogen storage technology safety, hydrogen storage density, high-efficiency hydrogen absorption and release, transportation safety, and engineering practice. © 2024 IEEE.

关键词： Aluminum

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Natural antimicrobial properties of liquid smoke derived from cocoa pod shells in meatball preservation

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South African Journal of Chemical engineering 2023年 46卷 106-111页

作者： Desvita, Hera Faisal, M. Mahidin, Mahidin Suhendrayatna Doctoral Program Post Graduate Program Universitas Syiah Kuala Indonesia Research Center for Chemistry National Research and Innovation Agency B.J. Habibie Science and Techno Park Serpong Banten South Tangerang 15314 Indonesia Chemical Engineering Department Faculty of Engineering Universitas Syiah Kuala Indonesia Halal Research Center Universitas Syiah Kuala Indonesia

The liquid smoke, which is produced by pyrolyzing wood materials containing cellulose, hemicellulose, and lignin, can be used to preserve food. Phenolic, acetic, and carbonyl compounds found in liquid smoke can serve as a natural preservative. This study aimed to determine meatball preservation ability of liquid smoke from cocoa pod shells. Specifically, cocoa pod shells were converted to liquid smoke using slow pyrolysis at three different temperatures, 300 °C, 340 °C and 380 °C. Prior to its use, liquid smoke was purified using distillation at 190 °C. Liquid smoke at concentrations of 0.5%–3.0% was then used to preserve meatballs using an immersion method. Total volatile base-nitrogen (TVB-N), total plate count (TPC), and most probable number (MPN) analyses were used to evaluate preservation performance of liquid smoke. The statistical methods for MPN using one-way ANOVA followed by Tukey's tests. The SNI (Standar Nasional Indonesia) threshold to test whether meatballs remained fresh (TVB-N <20 mg N/g). TPC test results indicated that beef meatballs stay fresh at room temperature for 42 h or 48 h of storage using 0.5% or 1%–3% liquid smoke concentrations, respectively. Based on MPN tests showed meatballs could last for 48 h for all samples. Liquid smoke produced from cocoa pod shells can be used as a natural preservative for beef meatballs;however, liquid smoke concentrations influence the maximum preservation period for meatballs. © 2023 The Author(s)

关键词： Cocoa pod shells Liquid smoke MPN Pyrolysis Total plate count Total volatile base-nitrogen

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Biomass-Based Discrete Furan Oligomers as materials for Electrochromic Devices

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ACS Sustainable Chemistry and engineering 2024年第1期12卷 459-469页

作者： Atayde, Eduardo C. Fong, Guan-Lun Yeh, Jyun-Yi Matsagar, Babasaheb M. Wang, Yu-Cheng Chen, De-Chian Peng, Chi-How Li, Yi-Pei Yamauchi, Yusuke Ho, Kuo-Chuan Wu, Kevin C.-W. Molecular Science and Technology Program Taiwan International Graduate Program (TIGP-MST) Academia Sinica No. 128 Sec. 2 Academia Road Taipei 11529 Taiwan Department of Chemistry National Tsing Hua University No. 101 Sec. 2 Kuang-Fu Road Hsinchu 30013 Taiwan Department of Chemical Engineering National Taiwan University No. 1 Sec. 4 Roosevelt Road Taipei 10617 Taiwan Sustainable Chemical Science and Technology Program Taiwan International Graduate Program (TIGP-SCST) Academia Sinica No. 128 Sec. 2 Academia Road Taipei 11529 Taiwan School of Chemical Engineering and Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensl Brisbane 4072 QLD Australia Department of Materials Process Engineering Graduate School of Engineering Nagoya University Nagoya 464-8603 Japan Institute of Polymer Science and Engineering National Taiwan University No.1 Sec. 4 Roosevelt Rd. Taipei 10617 Taiwan Department of Chemical Engineering and Materials Science Yuan Ze University No. 135 Yuandong Rd. Taoyuan 320 Taiwan

Electrochromic devices (ECDs) are materials that can undergo reversible changes in transmittance when exposed to different applied potentials. While many conjugated heterocyclic oligomers, such as oligothiophenes, have been developed for this purpose, there is no reported study on the use of discrete oligomeric furans as ECD materials. In this work, we introduce a furan trimer that can be utilized as a discrete electrochromic material, which transitions from light yellow to red and has a very high coloration efficiency of 1940 cm²/C at 507 nm. We propose that the reversible π-stack formation of the oligomer radical cations is behind this phenomenon, as evidenced by both experimental and computational results. The derivability of this oligomer from biomass and its facile synthesis make it an interesting alternative for other existing organic electrochromic materials. © 2023 American Chemical Society

关键词： electrochromism furan oligomer hydroxyalkylation−alkylation reaction solvatochromism π-stacks

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Multi-robot Map Exploration Based on Multiple Rapidly-Exploring Randomized Trees

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SN Computer science 2024年第1期5卷 31页

作者： Mukhopadhyay, Shayok Umari, Hassan Koirala, Koshish Electrical & Computer Engineering and Computer Science Department University of New Haven 300 Boston Post Rd West Haven 06516 CT United States Department of Electrical Engineering American University of Sharjah Sharjah P.O. Box 26666 United Arab Emirates Mechatronics Engineering graduate program American University of Sharjah Sharjah P.O. Box 26666 United Arab Emirates

A map is necessary for tasks such as path planning or localization, which are common to mobile robot navigation. However, a map may be unavailable if the environment in which a robot navigates is unknown. Creating a map requires an exploration algorithm. Such algorithms guide robots to boundaries that separate known portions of a map from the unknown portions. Such boundaries are known as frontiers. There are image processing-based algorithms that detect frontiers. The authors’ previous work uses two, i.e., local and global, rapidly exploring random trees (RRTs) for two-dimensional exploration using a single robot. The present work applies the above to a multiagent system with three robots. A market-based strategy is used to allocate exploration tasks to the robots. Results show that the developed exploration strategy successfully explores a map in a reasonable amount of time compared to image processing-based approaches, and also reduces the map exploration cost. This strategy is readily usable for three-dimensional exploration with drones. It is also shown that the usage of a local frontier detector along with a global frontier detector helps reduce exploration time compared to simply using a global frontier detector alone. As an outline to future work, the paper also shows an extension of the proposed approach towards three-dimensional mapping using a single robot. © 2023, The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd.

关键词： Exploration Mapping Multi-agent Navigation ROS RRT

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Accuracy of DFT computed oxygen-vacancy formation energies and high-throughput search of solar thermochemical water-splitting compounds

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Physical Review materials 2023年第6期7卷 065403-065403页

作者： Bianca Baldassarri Jiangang He Xin Qian Emanuela Mastronardo Sean Griesemer Sossina M. Haile Christopher Wolverton Graduate Program in Applied Physics Northwestern University Evanston Illinois USA Department of Materials Science and Engineering Northwestern University Evanston Illinois USA

The enthalpy change involved in metal oxide reduction is a key quantity in various processes related to energy conversion and storage and is of particular interest for computational prediction. Often this prediction involves the simulation of a high-temperature reduction process with a 0-K methodology like density functional theory (DFT), and it is not infrequent for the high temperature and 0-K stable crystal structures to differ. This introduces a conundrum with regard to the choice of crystal structure to utilize in the computation, with approaches in the literature varying and experimental validation remaining scarce. In this work, we address both the crystal structure conundrum and the experimental validation, and then apply the insights we gain to guide a high-throughput search for new materials for solar thermochemical water-splitting applications. By computing the DFT+U oxygen-vacancy formation energy (ΔEvf) of a selection of ABO3 compounds and comparing different crystal structures for each composition, we highlight the issues that arise when the structure utilized in the computation is dynamically unstable at 0 K, namely the presence of an artificial lowering of ΔEvf, and the lack of convergence of ΔEvf with cell size. We solve these limitations by identifying and employing a suitable surrogate dynamically stable structure. We then validate the predictive power of our calculations against appositely generated experimental measurements of reduction enthalpy for a series of Hubbard U values, finding an accuracy ranging between 0.2–0.6 eV/O. In light of such conclusions, we revise and expand a previous a high-throughput DFT study on ABO3 perovskite oxides. We provide a list of candidate STCH materials, highlight trends with redox-active cation and structural distortion, and identify Mn4+, Mn3+, and Co3+ as the most promising redox-active cations.

关键词： Energy applications First-principles calculations Hydrogen energy

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