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Thermo-hydraulic performance of a heat exchanger tube with inserted curved-wing tape vortex generators

AIP Conference Proceedings 2024年第1期3236卷

作者： Narin Koolnapadol Pongjet Promvonge Pitak Promthaisong Panuwat Hoonpong Chitakorn Khanoknaiyakarn Suabsakul Gururatana Sompol Skullong Department of Automotive Mechanical Engineering Faculty of Industrial Technology Rajabhat Rajanagarindra University Chachoengsao 24000 Thailand Department of Mechanical Engineering School of Engineering King Mongkut’s Institute of Technology Ladkrabang Bangkok 10520 Thailand Heat Pipe and Thermal Tool Design Research Unit (HTDR) Faculty of Engineering Mahasarakham University Maha Sarakham 44150 Thailand Department of Mechanical Technology Faculty of Industrial Technology Thepsatri Rajabhat University Lopburi 15000 Thailand Division of Engineering Management Graduate School Southeast Asia University 19/1 Petchkasem Road Nongkhangphlu Nonghkaem Bangkok 10160 Thailand Energy Systems Research Group Department of Mechanical Engineering Faculty of Engineering at Sriracha Kasetsart University Sriracha Campus 199 M.6 Sukhumvit Rd. Sriracha Chonburi 20230 Thailand

In the current study, thermal patterns and flow resistance in a heat exchange tube equipped with a curved-wing tape (CWT) vortex generator were experimentally analyzed to boost performance. A range of Reynolds numbers (Re) from 4130 to 25,370 was utilized in the experiment. The curved wings were arranged in forward array patterns for pitch length ratios (P/D = PR = 2.5, 2, and 1.5) and three wing attack angles (α = 10°, 20°, and 30°). The friction factor, f, and the Nusselt number, Nu, were utilized to quantify the pressure loss and heat transmission caused by the CWT insertion. The measured data reveal that utilizing the CWT resulted in a roughly 2.55-4.37 times greater increase in Nu than the smooth tube, whereas the rise in f is approximately 7.36-46.9 times. Raising the α value causes the Nu and f to trend upward, but increasing PR causes them to trend downward. The CWT’s maximal thermal performance is approximately 1.58 at α = 10° and PR = 1.5. Correlations for f and Nu in the functional form of the CWT parameters have also been established.

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FIELD METHODS FOR MEASUREMENT OF GROUND-WATER REDOX CHEMICAL-PARAMETERS

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GROUND WATER MONITORING AND REMEDIATION 1990年第4期10卷 81-89页

作者： WALTONDAY, K MACALADY, DL BROOKS, MH TATE, VT Katherine Walton-Day received an A.B. in geology from Smith College (1981) and an M.S. in geology from the Colorado School of Mines (1986). She is currently a Ph.D. candidate in geology at the Colorado School of Mines and is employed as a geologist at the U. S. Geological Survey Geologic Division in Denver Colorado(USGS Box 25046 MS973 Denver CO 80225). Her research involves studying the processes controlling the mobility of trace metals in pristine and contaminated natural systems. Donald L. Macalady received a B.S. in chemical engineering from Pennsylvania State University in 1963 and a Ph.D. in chemistry from the University of Wisconsin in 1969. He has held positions at Grinnell College (1968–1970) Northern Michigan University (1970–1982) and the Colorado School of Mines (1982-present) (Department of Chemistry and Geochemistry Colorado School of Mines Golden CO 80401). His research interests include chemical reactions of anthropogenic organic chemicals in natural water systems chemistry of metals and metal-organic complexes in natural and polluted water systems aqueous analytical chemistry and surface chemistry of natural particles. He is a member of ACS AAAS and ASLO and serves as an associate editor to the Journal of Contaminant Hydrology. Myron H. Brooks received a B.S. in biology from Emory University (1979). He is a graduate student in the Department of Chemistry and Geochemistry at the Colorado School of Mines. Brooks is a research chemist for the U. S. Geological Survey Water Resources Division in Arvada Colorado (USGS Box 25046 MS408 Denver CO 80225). He has participated in numerous investigations of ground water surface water and wet deposition chemistry over the last 10 years. His current research is focused on microbial processes in contaminated ground water. Vernon T. Tate studied mechanical engineering at the University of Denver. He was employed by Union Carbide for 27 years. While employed by Union Carbide he worked as an analyst was in charge of developing a QA/QC lab for

An inexpensive, versatile, and portable system is presented, which facilitates rapid field determinations of redox potentials, pH, conductivity, ferrous and total iron, nitrite, specific conductance, dissolved oxygen, and temperature. Accuracy is facilitated by on-site measurements of most parameters using specially constructed flow-through cells and, for several analyses, sealed reagent ampoules, which can be broken and developed inside a flowing stream of ground water. Coupled with laboratory analyses of more stable ground water parameters, this system can provide accurate and relatively inexpensive determinations of redox conditions in ground water.

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Symmetries and synchronization from whole-neural activity in C. elegans connectome: Integration of functional and structural networks

arXiv

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arXiv 2024年

作者： Avila, Bryant Augusto, Pedro Phillips, David Gili, Tommaso Zimmer, Manuel Makse, Hernán A. Levich Institute and Physics Department City College of New York New YorkNY10031 United States Vienna Austria Vienna Biocenter PhD Program Doctoral School the University of Vienna Medical University of Vienna Vienna Austria Mechanical Engineering Department University of New Mexico AlbuquerqueNM87131 United States Networks Unit IMT Scuola Alti Studi Lucca Piazza San Francesco 15 Lucca55100 Italy Department of Radiology Neuroradiology Service Memorial Sloan Kettering Cancer Center New YorkNY10065 United States CUNY Neuroscience Graduate Center City University of New York New YorkNY10031 United States

Understanding the dynamical behavior of complex systems from their underlying network architectures is a long-standing question in complexity theory. Therefore, many metrics have been devised to extract network features like motifs, centrality, and modularity measures. It has previously been proposed that network symmetries are of particular importance since they are expected to underly the synchronization of a system’s units, which is ubiquitously observed in nervous system activity patterns. However, perfectly symmetrical structures are difficult to assess in noisy measurements of biological systems, like neuronal connectomes. Here, we devise a principled method to infer network symmetries from combined connectome and neuronal activity data. Using nervous system-wide population activity recordings of the *** backward locomotor system, we infer structures in the connectome called fibration symmetries, which can explain which group of neurons synchronize their activity. Our analysis suggests functional building blocks in the animal’s motor periphery, providing new testable hypotheses on how descending interneuron circuits communicate with the motor periphery to control behavior. Our approach opens a new door to exploring the structure-function relations in other complex systems, like the nervous systems of larger animals. © 2024, CC BY.

关键词： Synchronization

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NAVAL SHIP DESIGN - EVOLUTION OR REVOLUTION

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NAVAL ENGINEERS JOURNAL 1988年第3期100卷 40-52页

作者： TIBBITTS, BF KEANE, RG RIGGINS, RJ Captain Barry Tibbitts USN: was graduated from the U.S. Naval Academy in 1956 and subsequently served as a gunnery division officer in an attack aircraft carrier and as gunnery officer operations officer and chief engineer in two diesel submarines. He attended MIT from 1962–1965 earning a master of science in mechanical engineering and a naval engineers degree. Early assignments as an engineering duty officer included SRF Yokosuka CINCPACFLT staff and SupShip Pascagoula. From 1976 to 1987 he served in a variety of senior ship design assignments: CVV ship design manager director NAVSEC Hull and Ship Design Divisions director NavSea Ship Design Management and Integration Office commander David Taylor Naval Ship R&D Center and director NavSea Ship Design Group. Recently retired but recalled to active duty he is the professor of naval construction and engineering at MIT. He has received seven personal decorations including two Legion of Merit awards. Robert G. Keane Jr.:is currently the deputy director of the NavSea Ship Design Group. He has been employed by NavSea and its predecessor organizations for over twenty years. He is a graduate of The Johns Hopkins University from which he received his B.E.S. degree in mechanical engineering in 1962. He received his M.E. degree in mechanical engineering in 1967 from Stevens Institute of Technology and in 1970 his M.S.E. degree in naval architecture and marine engineering from the University of Michigan. Mr. Keane held increasingly responsible design positions involving ship arrangements hull equipment hull form and hydrodynamic performance before being selected in 1981 for the Senior Executive Service to be director of the Naval Architecture Subgroup. Following an assignment at the David Taylor Research Center as assistant for transition of ship engineering technology he served as director of the Ship Survivability Subgroup until assuming his current position in 1985. He is an active member of ASNE SNAME and ASE. Robert Riggins:received a B.S. in mechanical

Some fairly radical changes to the naval ship design process occurred during the 1970s. The decade of the 80s has also witnessed a steady stream of changes. One of the most significant was the establishment of the Ship Characteristics Improvement Board (SCIB) in the Office of the Chief of Naval Operations (OpNav), and the resulting influence on the dialog between the military requirements decision makers and the Navy's ship designers. Other changes have occurred for which the impacts are less clear. These include establishment of the chief engineer of the Navy (ChEng) position, creation of the Space and Naval Warfare systems Command (SpaWar) and OpNav's “Revolution at Sea” initiative. This paper will describe and discuss these and other changes, and comment on the resultant impact. The authors will attempt to present a global view of the total pattern of changes and try to discern if we are on a path of revolution, or merely normal evolution.

关键词： NAVAL VESSELS

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INNOVATIONS IN COMPUTER-AIDED-DESIGN OF MARINE TURBINES USING INTERACTIVE GRAPHICS

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NAVAL ENGINEERS JOURNAL 1980年第2期92卷 207-217页

作者： GINGRICH, JK WINTER, RL Mr. John K. Gingrich joined the General Electric Company after his graduation from Lafayette College in 1948. His early assignments were with the General Engineering Laboratory and the Knolls Atomic Power Laboratory in Schenectady. N. Y. He joined the Marine Turbine and Gear Department in 1968 as Manager Engineering Administration. and assumed his present assignment as Manager Engineering Resource Planning & Administration in 1976. Mr. Gingrich was instrumental in procuring the Interactive Graphics System for the Medium Steam Department. having headed up the Study Team and is now responsible for the Interactive Graphics Systems management including new procurements. He is a member of the American Institute of Design Drafting and is currently the Chairman of the Computer-Aided Drafting Committee in that organization. Mr. Reinhold L. Winter is a graduate of the General Electric Apprentice Program and Salem State College from which he received his B.S. degree in Business Administration. He has nineteen years experience with the General Electric Company including eight years in Business Systems and Programming two years in Computer Operations Management and six years in his present position as Manager Engineering Business Systems. He was a member of the original Study Team that investigated and selected the present Applicon Interactive Graphics (IAG) equipment and currently is responsible for the management of software and hardware support for the ZAG Facility.

This paper discusses the Interactive Graphics System used by the General Electric Company, Medium Steam Turbine Department (engineering & Manufacturing) for designing, drafting, and manufacturing applications. A brief overview of the hardware malting up the system is described, followed by a more detailed description of the actual applications. Two-dimensional applications described include a Heat Balance Analysis, Flow Diagrams, and Electrical Schematics. A more fruitful area for increased productivity gains is described in the three-dimensional or mechanical applications including turbine design & layout and bucket design. coordination of the design with manufacturing for numerical control tape generation is described through CAM and Plate Frame Cutting applications. Finally, a short review of the engineering design work using Interactive Graphics is discussed. Productivity gains of 2.6 to 1 are being realized, and the overall savings to the Medium Steam Department are outlined.

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Non-linear optics at twist interfaces in h-BN/SiC heterostructures

arXiv

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arXiv 2023年

作者： Biswas, Abhijit Xu, Rui Alvarez, Gustavo A. Zhang, Jin Christiansen-Salameh, Joyce Puthirath, Anand B. Burns, Kory Hachtel, Jordan A. Li, Tao Iyengar, Sathvik Ajay Gray, Tia Li, Chenxi Zhang, Xiang Kannan, Harikishan Elkins, Jacob Pieshkov, Tymofii S. Vajtai, Robert Birdwell, A. Glen Neupane, Mahesh R. Garratt, Elias J. Ivanov, Tony Pate, Bradford B. Zhao, Yuji Zhu, Hanyu Tian, Zhiting Rubio, Angel Ajayan, Pulickel M. Department of Materials Science and Nanoengineering Rice University HoustonTX77005 United States Sibley School of Mechanical and Aerospace Engineering Cornell University IthacaNY14853 United States Max Planck Institute for the Structure and Dynamics of Matter Center for Free-Electron Laser Science Luruper Chaussee 149 22761 Germany Department of Materials Science & Engineering University of Virginia CharlottesvilleVA22904 United States Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak RidgeTN37831 United States Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States DEVCOM Army Research Laboratory RF Devices and Circuits AdelphiMD20783 United States Chemistry Division Naval Research Laboratory WashingtonDC20375 United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Flatiron Institute New YorkNY10010 United States

Understanding the emergent electronic structure in twisted atomically thin layers has led to the exciting field of twistronics. However, practical applications of such systems are challenging since the specific angular correlations between the layers must be precisely controlled and the layers have to be single crystalline with uniform atomic ordering. Here, we suggest an alternative, simple and scalable approach where nanocrystalline two-dimensional (2D) film on three-dimensional (3D) substrates yield twisted-interface-dependent properties. Ultrawidebandgap hexagonal boron nitride (h-BN) thin films are directly grown on high in-plane lattice mismatched wide-bandgap silicon carbide (4H-SiC) substrates to explore the twist-dependent structure-property correlations. Concurrently, nanocrystalline h-BN thin film shows strong nonlinear second-harmonic generation and ultra-low cross-plane thermal conductivity at room temperature, which are attributed to the twisted domain edges between van der Waals stacked nanocrystals with random in-plane orientations. First-principles calculations based on time-dependent density functional theory manifest strong even-order optical nonlinearity in twisted h-BN layers. Our work unveils that directly deposited 2D nanocrystalline thin film on 3D substrates could provide easily accessible twist-interfaces, therefore enabling a simple and scalable approach to utilize the 2D-twistronics integrated in 3D material devices for next-generation nanotechnology. © 2023, CC BY.

关键词： Harmonic generation

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A new model for simulating heat, air and moisture transport in porous building materials

arXiv

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arXiv 2019年

作者： Berger, Julien Dutykh, Denys Mendes, Nathan Rysbaiuly, Bolatbek Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS LOCIE Chambéry73000 France LOCIE UMR 5271 CNRS Université Savoie Mont Blanc Campus Scientifique Le Bourget-du-Lac CedexF-73376 France Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS LAMA Chambéry73000 France LAMA UMR 5127 CNRS Université Savoie Mont Blanc Campus Scientifique Le Bourget-du-Lac CedexF-73376 France Thermal Systems Laboratory Mechanical Engineering Graduate Program Pontifical Catholic University of Paraná Rua Imaculada Conceição 1155 Curitiba - ParanáCEP: 80215-901 Brazil International Information Technology University Manas Str. 34/1 Almaty Kazakhstan

This work presents a detailed mathematical model combined with an innovative efficient numerical model to predict heat, air and moisture transfer through porous building materials. The model considers the transient effects of air transport and its impact on the heat and moisture transfer. The achievement of the mathematical model is detailed in the continuity of Luikov's work. A system composed of two advection-diffusion differential equations plus one exclusively diffusion equation is derived. The main issue to take into account the transient air transfer arises in the very small characteristic time of the transfer, implying very fine discretisation. To circumvent these difficulties, the numerical model is based on the Du Fort-Frankel explicit and unconditionally stable scheme for the exclusively diffusion equation. It is combined with a two-step Runge-Kutta scheme in time with the Scharfetter-Gummel numerical scheme in space for the coupled advection-diffusion equations. At the end, the numerical model enables to relax the stability condition, and, therefore, to save important computational efforts. A validation case is considered to evaluate the efficiency of the model for a nonlinear problem. Results highlight a very accurate solution computed about 16 times faster than standard approaches. After this numerical validation, the reliability of the mathematical model is evaluated by comparing the numerical predictions to experimental observations. The latter is measured within a multi-layered wall submitted to a sudden increase of vapor pressure on the inner side and driven climate boundary conditions on the outer side. A very satisfactory agreement is noted between the numerical predictions and experimental observations indicating an overall good reliability of the proposed model. Copyright © 2019, The Authors. All rights reserved.

关键词： Numerical models

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The Combined Multi-objective Optimization Design for a Light Guide Rod

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IOP Conference Series: Materials Science and engineering 2013年第1期46卷

作者： Yu-Sen Yang Chun-Yao Shih Hong-Yao Chien Rong-Fong Fung Department of Mechanical & Automation Engineering National Kaohsiung First University of Science and Technology 1 University Road Yenchau Kaohsiung County 824 Taiwan Graduate Institute of Electro-optical Engineering National Kaohsiung First University of Science and Technology 1 University Road Yenchau Kaohsiung County 824 Taiwan Industrial Master Program on Advanced Headlamp Industry National Kaohsiung First University of Science and Technology 1 University Road Yenchau Kaohsiung County 824 Taiwan

The light guide rod (LGR) has been popularly used for the vehicles, and the automobile lamp industries need mass production to match this trend. This paper aims to develop a systemic way to find the best parameters' combination for the LGR, and the parameters are usually restricted to some levels and random values. In this paper, the LGR example with two optical performances of illuminance flux and uniformity is to be optimized by use of the real-coded genetic algorithm (RGA) and grey relational analysis (GRA). The illuminance flux and uniformity of the best parameters' combination are obtained and compared with the initial set. Comparisons with Taguchi-Grey can improve 5% of gain and comparisons with Pareto genetic algorithm (PaGA) can improve 1.7% of gain. The combined multi-objective optimization can saving 7% time and it is found that the new proposed method has positive gains in performances.

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ADVANCED AVIONICS ARCHITECTURE - THE NAVAIR STUDY

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NAVAL ENGINEERS JOURNAL 1994年第6期106卷 31-40页

作者： KATZ, RS JAHNKE, L JEWETT, CE Cdr. Larry Jahnke USN:is presently Head of the Architecture Branch of the Avionics Engineering division AIR-546 of the Naval Air Systems Command. Among his current responsibilities is to lead implementation activities of the NAVAIR Advanced Avionics Architecture study described in this paper. Cdr. Jahnke graduated from the University of Minnesota with a B.S. degree in aeronautical engineering and was commissioned in 1974. After flight training as a Naval flight officer he was assigned to Naval Air Station Barbers Point Hawaii where he served as Tactical Coordinator for P-3B aircraft. He was assigned to the Communications Directorate of the Joint Staff in 1990 where he participated in support of Desert Shield/Desert Storm and was part of the original cadre of officers responsible for the “C41 for the Warrior” concept. Cdr. Jahnke also has a Master of Science degree from the University of Southern California and is a 1990 graduate of the Industrial College of the Armed Forces. Cdr. Charles E. Jewett USN:is currently the Common Avionics Requirements Officer for Naval Aircraft Programs. He has served the Navy as an Aeronautical Engineering Duty Officer since 1982 with previous defense acquisition assignments as the Avionics Architecture and Engineering Branch Head Fighter/Attack Avionics systems Engineering Branch Head and A-12 Avionics Officer and A-6F Deputy Program Manager and the A-6 Avionics Officer. Cdr. Jewett entered the Navy as an Aviation Officer Candidate in 1971 receiving his commission and earning his wings as a Naval Flight Officer the same year. After graduating from the U.S. Naval Test Pilot School in 1976 he was assigned to the Strike Aircraft Test Directorate of the Naval Air Test Center where he participated in various electronic warfare electro-optics and software update evaluations for A-6 EA-6B and OV-10 aircraft. In Cdr. Jewett's previous assignment at NAVAIRSYSCOM he led a major Avionics Architecture Study (the subject of this paper) that surveyed cutting-edge avionics technol

To establish a planning basis for future avionics systems, the Naval Air systems Command (NAVAIR) conducted an avionics architecture investigation during 1992-1993, culminating in a final report published in August 1993. In the course of the study, U.S. Industry provided significant information to a NAVAIR avionics database for both technologies and systems integration methods. From the study emerged an implementation strategy to allow NAVAIR to develop effective avionics systems in the future that use commercial products and standards where applicable but also allow the ready use of new and emerging technologies. Recommended strategies concentrate on the development process, especially the use of sound systems engineering techniques and the maximum practical use of commercial standards and products. This paper reviews the methodology employed during the NAVAIR investigation, and presents the key findings and resulting implementation strategies. The paper concludes with a brief summary of current implementation plans at NAVAIR.

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Human osteoblast and fibroblast behavior on modified zirconia implant surfaces

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Clinical Oral Implants Research 2018年第S17期29卷

作者： Mariana Cruz Joana Marques Gabriella Peñarrieta-Juanito Filipe Silva António Mata Mafalda Costa Georgina Miranda Júlio Souza Ricardo Magini Silvio Mario Meloni João Caramês Faculty of Dental Medicine Universidade de Lisboa Portugal Oral Biology and Biochemistry Research Group LIBPhys Faculty of Dental Medicine University of Lisbon Portugal Center for Research on Dental Implants Post-graduate program in dentistry (PPGO) School of Dentistry Federal University of Santa Catarina (UFSC) Brazil Center for Microelectromechanical Systems (CMEMS) Dept. of Mechanical Engineering University of Minho Portugal Center for Research on Dental Implants Post-graduate program in dentistry (PPGO) School of Dentistry Federal University of Santa Catarina (UFSC) Portugal NA Italy Faculty of Dental Medicine University of Lisbon Portugal

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