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Chang, Liang, Zhiwei Li, Sheng Li, Wenang Jia y Jian Ruan. "Heat Loss Analysis of a 2D Pump’s Transmission". Machines 10, n.º 10 (26 de septiembre de 2022): 860. http://dx.doi.org/10.3390/machines10100860.
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Highly enhanced pump power density inevitably results in a profound rise in pump temperature, which seriously influences both power loss and service performance. Heat loss analysis is an important part of analyzing the mechanical and cooling efficiency of a 2D piston pump. This paper focuses on heat loss analysis of this pump’s transmission. Firstly, theoretical and experimental studies are carried out on the thermal–hydraulic model to investigate the heat loss of the pump’s transmission. A pump test rig is developed and thermal experiments are conducted, from 1000 rpm to 6000 rpm. Furthermore, its transient thermal simulation model is implemented with Ansys software to capture the pump’s thermal status. The test convective heat transfer coefficients and temperature data are set in the model, and the simulation results are mutually validated with the experimental ones. Finally, the transmission’s heat loss is compared with its reference churning loss formula. The distribution of the transient heat loss is 49.66% into the end cap, 27.74% into the cylinder head, 13.30% into the inner cylinder, and 9.30% into the oil. The heat loss simulation results agree with the churning loss below 4000 rpm; therefore, the transmission thermal model is accurate and efficient.
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Kalua, Amos y James Jones. "Epistemological Framework for Computer Simulations in Building Science Research: Insights from Theory and Practice". Philosophies 5, n.º 4 (22 de octubre de 2020): 30. http://dx.doi.org/10.3390/philosophies5040030.
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Computer simulations are widely used within the area of building science research. Building science research deals with the physical phenomena that affect buildings, including heat and mass transfer, lighting and acoustic transmission. This wide usage of computer simulations, however, is characterized by a divergence in thought on the composition of an epistemological framework that may provide guidance for their deployment in research. This paper undertakes a fundamental review of the epistemology of computer simulations within the context of the philosophy of science. Thereafter, it reviews the epistemological framework within which computer simulations are used in practice within the area of building science research. A comparison between the insights obtained from the realms of theory and practice is made, which then interrogates the adequacy of the epistemological approaches that have been employed in previously published simulation-based research. These insights may help in informing a normative composition of an adequate epistemological framework within which computer simulation-based building science research may be conducted.
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Kuokkala, V. T. "Computer simulation of transmission electron micrographs by microscope for windows". Proceedings, annual meeting, Electron Microscopy Society of America 54 (11 de agosto de 1996): 126–27. http://dx.doi.org/10.1017/s0424820100163095.
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microScope for Windows™ is a transmission electron micrograph simulation program for brightfield and darkfield images of dislocations and stacking faults, based on the dynamical two-beam theory and the column approximation. The program is a modification of the original programs of Head et al, which have been rewritten in Visual Basic™ 4.0 for Microsoft® Windows™ 3.1. microScope for Windows™ also includes routines needed to prepare data for the actual calculation of the image, and to calculate and display a rocking curve for any pixel of the previously computed brightfield or darkfield image. On a 120 MHz Pentium, microScope for Windows™ calculates a true gray scale (256 gray level) image consisting of 19840 pixels in about 10 seconds (version 2.3). A 300 dpi laserprinter screendump at the end of the calculation of an image is shown in Fig. 1.
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Liang, Qing, Jing Liu, Wen Zhong Xu y Gang Xu. "Optimization of the Optical Performance of TiO2/Ag/TiO2 Multilayers for Warm Climates". Advanced Materials Research 168-170 (diciembre de 2010): 936–39. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.936.
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The optical performance of the heat mirror for warm climates was proposed, and a parameter Dx which equals the ratio of solar transmission to visible transmission was defined. To make the Dx as low as possible, the thicknesses of the films for TiO2/Ag/TiO2multilayers were optimized through computer simulation. A TiO2(140 nm)/Ag (16 nm)/TiO2(140 nm) structure optimized for 16-nm Ag has a maximum decrease in Dx value (from 0.75 to 0.51), which possesses excellent building energy efficiency.
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Huo, Wen. "Thermal Simulation Analysis of Internal Control Circuit Board of Steering Gear Box Based on COMSOL Three-Dimensional Simulation Software". Computational Intelligence and Neuroscience 2022 (24 de marzo de 2022): 1–20. http://dx.doi.org/10.1155/2022/3006349.
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The steering gear device includes two parts, a steering gear control circuit and a transmission component. The transmission component includes a ball screw and a motor. During the operation of the steering gear, due to the presence of the steering gear ball screw motor and friction, a certain amount of heat will be generated, which will affect the steering gear control circuit in a confined space. At the same time, the steering gear is inevitable in the actual working process, and will experience a high temperature environment, which will increase the temperature of the internal structure of the steering gear, and due to the difference in thermal expansion coefficients between various materials, stress and strain will occur in the structure, which may cause mismatch or even cracks in the system structure, and the steering gear system cannot work normally. It is necessary to analyze the thermal characteristics of the overall steering gear under multiple factors. Based on this, this paper uses COMSOL three-dimensional simulation software to conduct thermal simulation analysis on the shell of the steering gear containing the control circuit board. The temperature distribution and stress-strain response law of the control circuit board in the box, and the influence of different materials and thickness of the box heat insulation layer on the thermal characteristics of the control circuit are discussed, and then a reasonable thickness and material of the heat insulation layer are obtained for the design of the rudder chassis for reference.
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Hopmann, Christian y Suveni Kreimeier. "Modelling the Heating Process in Simultaneous Laser Transmission Welding of Semicrystalline Polymers". Journal of Polymers 2016 (27 de octubre de 2016): 1–10. http://dx.doi.org/10.1155/2016/3824065.
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Laser transmission welding is an established joining process for thermoplastics. A close-to-reality simulation of the heating process would improve the understanding of the process, facilitate and shorten the process installation, and provide a significant contribution to the computer aided component design. For these reasons a thermal simulation model for simultaneous welding was developed which supports determining the size of the heat affected zone (HAZ). The determination of the intensity profile of the laser beam after the penetration of the laser transparent semicrystalline thermoplastic is decisive for the simulation. For the determination of the intensity profile two measurement systems are presented and compared. The calculated size of the HAZ shows a high concordance to the dimensions of the HAZ found using light microscopy. However, the calculated temperatures exceed the indicated decomposition temperatures of the particular thermoplastics. For the recording of the real temperatures during the welding process a measuring system is presented and discussed.
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Noémi Zetz, Dóra y István Kistelegdi. "Comfort simulation supported sketch plan optimization of the University of Pécs, Medical School extension". Pollack Periodica 15, n.º 2 (agosto de 2020): 166–77. http://dx.doi.org/10.1556/606.2020.15.2.15.
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Abstract:During sketch design stage for the new block of the University of Pécs, Medical School comfort and lighting simulations were applied to quantify optimization strategies. Simulation cases about shading possibilities, façade glazing ratios and internal heat storage masses evaluate the impact of illumination, solar gains, loads and heat transmission on visual and thermal comfort. The goal was to select the most favorable comfort, coupled with maximum reduction of investment costs. Concepts represent 14% (shading), 10% (reduced wall-window ratio), 11% (slabs without suspended ceilings), and 17% (combined wall-window ratio and thermal mass) improvement in thermal comfort performance, and it was proposed for further design.
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Lim, Huey Sia, Nayan Nafarizal, Mohd Zainizan Sahdan, Samsul Haimi Dahlan, Zuhairiah Zainal Abidin, Muhammad Yusof Ismail, Fauziahanim Che Seman et al. "Optimization of Transmission Lost for Energy Saving Glass with Different Sheet Resistance Values". Advanced Materials Research 832 (noviembre de 2013): 233–36. http://dx.doi.org/10.4028/www.scientific.net/amr.832.233.
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Recently, energy saving glass is commonly applied in the modern engineered building. This is due to its advantages of keeping the heat inside the building in winter while rejecting the heat when in summer. The typical energy saving glass is made by applying a very thin metallic oxide such as silver oxide or tin oxide on one side of the float glass. But at the same time, it has the disadvantages of attenuates useful microwave frequencies that ranging from 0.8 2.2 GHz. The examples of the microwave frequency at this range are GSM mobile signal, GPS and personal communication. Frequency selective surface (FSS) has been introduced to overcome this drawback of energy saving glass. In this study, the transmission of the microwave signal is observed through the simulation using Computer Simulation Technology Microwave Studio. Bandpass frequency selective surface of cross dipole shape is used for the simulation. In the simulation, conductivity and electrical properties of glass and metal oxide thin film are important. The microwave transmission was evaluated at various sheet resistance of metal oxide thin film. The results show that the minimum transmission lost increased with the ohmic resistance increased. On the other hand, the peak frequency at various sheet resistance shows constant value at around 1.25-1.30 GHz. The full width half maximum of the microwave transmission increases with the sheet resistance value. The results suggest that FSS structured metal oxide thin film with lowest sheet resistance transmits more signal in the range for GSM phone signal.
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Della Torre, Augusto, Gianluca Montenegro, Angelo Onorati, Sumit Khadilkar y Roberto Icarelli. "Multi-Scale CFD Modeling of Plate Heat Exchangers Including Offset-Strip Fins and Dimple-Type Turbulators for Automotive Applications". Energies 12, n.º 15 (1 de agosto de 2019): 2965. http://dx.doi.org/10.3390/en12152965.
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Plate heat exchangers including offset-strip fins or dimple-type turbulators have a wide application in the automotive field as oil coolers for internal combustion engines and transmissions. Their optimization is a complex task since it requires targeting different objectives: High compactness, low pressure drop and high heat-transfer efficiency. In this context, the availability of accurate Computational Fluid Dynamics (CFD) simulation models plays an important role during the design phase. In this work, the development of a computational framework for the CFD simulation of compact oil-to-liquid heat exchangers, including offset-strip fins and dimples, is presented. The paper addresses the modeling problem at different scales, ranging from the characteristic size of the turbulator geometry (typically µm–mm) to the full scale of the overall device (typically cm–dm). The simulation framework is based on multi-scale concept, which applies: (a) Detailed simulations for the characterization of the micro-scale properties of the turbulator, (b) an upscaling approach to derive suitable macro-scale models for the turbulators and (c) full-scale simulations of the entire cooler, including the porous models derived for the smaller scales. The model is validated comparing with experimental data under different operating conditions. Then, it is adopted to investigate the details of the fluid dynamics and heat-transfer process, providing guidelines for the optimization of the device.
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Alzu’bi, Oruba Ahmad Saleh, Firas A. Alwawi, Mohammed Z. Swalmeh, Ibrahim Mohammed Sulaiman, Abdulkareem Saleh Hamarsheh y Mohd Asrul Hery Ibrahim. "Energy Transfer through a Magnetized Williamson Hybrid Nanofluid Flowing around a Spherical Surface: Numerical Simulation". Mathematics 10, n.º 20 (16 de octubre de 2022): 3823. http://dx.doi.org/10.3390/math10203823.
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A computational simulation of Williamson fluid flowing around a spherical shape in the case of natural convection is carried out. The Lorentz force and constant wall temperature are taken into consideration. In addition, upgrader heat transfer catalysts consisting of multi-walled carbon tubes, molybdenum disulfide, graphene oxide, and molybdenum disulfide are employed. The Keller box approach is used to solve the mathematical model governing the flow of hybrid Williamson fluid. To validate our findings, the key parameters in the constructed model are set to zero. Next, the extent of the agreement between our results and published results is observed. Numerical and graphical results that simulate the impressions of key parameters on physical quantities related to energy transmission are obtained, discussed, and analyzed. According to the results of this study, increasing the value of the Weissenberg number causes an increase in both the fluid temperature and drag force, while it also leads to a decrease in both the velocity of the fluid and the rate of energy transmission. Increasing the magnetic field intensity leads to a reduction in the rate of heat transfer, drag force, and fluid velocity while it has an appositive effect on temperature profiles.
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Fan, Youping, Peng Zhang, Ben Shang, Dianlang Wang, Wen’an Li, Dongjian Zhuang, Zihan Chen, Zhaoyi Zhang y Wu Wen. "Thermal Characteristic Simulation Study of Multicolumn Parallel Zinc Oxide Arresters under Extreme Operating Conditions". Electronics 12, n.º 1 (26 de diciembre de 2022): 100. http://dx.doi.org/10.3390/electronics12010100.
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The arrester plays an important role in the protection of the DC transmission system, and its thermal characteristics under different operating conditions greatly affect its performance. To study the thermal characteristics of multicolumn parallel arresters under extreme operating conditions in a DC system, considering the influence of SF6 fluid, the structural parameters of the ±500 kV Niu Cong DC transmission project were applied for this research. Firstly, a 3D model of the four-column parallel zinc oxide arrester installed on the neutral bus of the ±500 kV Niu Cong DC transmission project was built in ANSYS to analyze its thermal conduction. Then, the electromagnetic transient model of the Niu Cong DC transmission system was established in PSCAD to study the withstood energy of a four-column parallel zinc oxide arrester under 22 typical fault conditions in three operation modes. Based on the extreme operating conditions obtained, simulations of steady-state and transient thermal characteristics were performed considering the influence of SF6 fluid flow on the heat dissipation of the arrester. Finally, the field-test temperature test on the four-column parallel zinc oxide arrester was carried out to validate the effectiveness of the proposed simulation model and calculation method, with simulation data matching well with the field-test data. The results also conclude the thermal characteristics findings to reveal the thermal conduction of multicolumn arresters under extreme operating conditions.
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Li, X. M., Y. F. Tong y An Feng Hui. "Dynamic Simulation of the Assembly Process of Spindle Box of Machine Tool". Key Engineering Materials 455 (diciembre de 2010): 503–6. http://dx.doi.org/10.4028/www.scientific.net/kem.455.503.
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Based on the analyzed transmission process of spindle head and combined with the analyzed assembly process of spindle box, it determined the relationships of transmission and assembly between the various components of the spindle head. Firstly, using software of computer-aided design (UG6), it established a 3D parts library of spindle box of machine tool. Secondly, we had been developed dynamic simulation and power transmission simulation software of the assembly process of the spindle box of machine tool. It could realistically reproduce the disassembly process and the power transmission process of spindle box of machine tool when running the software. The software not only could be used for the old products to analysis and improvement, but also could be used for development of new products, and to some extent, the prototype could be replaced by it. The software was one of the essential tools for both the training of related employees and teaching of mechanical engineering students.
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Pu, Ziheng, Chenqu Zhou, Yuyao Xiong, Tian Wu, Guowei Zhao, Baodong Yang y Peng Li. "Two Dimensional Axisymmetric Simulation Analysis of Vegetation Combustion Particles Movement in Flame Gap under DC Voltage". Energies 12, n.º 19 (20 de septiembre de 2019): 3596. http://dx.doi.org/10.3390/en12193596.
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In recent years, extreme high temperature weather occurs frequently, which easily causes forest fires. The forest fire is prone to the trip accident of the transmission line. Previous studies show that charged combustion particles cause electric field distortion in the gap below the transmission line, and trigger discharges near the conductor area. The motion and distribution characteristics of combustion particles in the gap have an important influence on the discharge characteristics. Therefore, the size and morphology of combustion particles are analyzed through combustion experiments with typical vegetation. The combustion particles are mainly affected by the air drag force, electric field force and gravity. The interaction and influence of temperature, fluid, electric field and the multi-physical field of particle motion are comprehensively analyzed. A two dimensional (2D) axisymmetric simulation model is established by simplifying the flame region. According to the heat release rate of vegetation flame combustion, the fluid temperature and velocity are calculated. Combined with the fluid field and electric field, the forces on particles and movement are calculated. The results can provide a basis for the analysis of the electric field distortion, and further study the discharge mechanism of the gap under the condition of vegetation flame.
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Huang, Bonan, Chaoming Zheng, Qiuye Sun y Ruixue Hu. "Optimal Economic Dispatch for Integrated Power and Heating Systems Considering Transmission Losses". Energies 12, n.º 13 (28 de junio de 2019): 2502. http://dx.doi.org/10.3390/en12132502.
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To address the problem of the supply–demand imbalance caused by network transmission losses in integrated power and heating systems (IPHS), this paper presents an optimal economic dispatch strategy to minimize system operation cost and realize coordination and optimization between power and heat. Firstly, an innovative economic dispatch model considering transmission losses is developed, where both power and heat transmission losses models are established with good precision together. In addition, the coordination equation is derived from the formulated nonlinear, multi-constrained coupling optimization problem, where the coordination relationship of units’ outputs is clearly analyzed in an analytic way. Then, a double- λ -iteration algorithm is proposed, which can not only effectively solve the nonlinear coupling optimization problem but also decrease computation burden with faster convergence rate. Finally, simulations performed on five case studies illustrate the satisfying performance of the presented strategy.
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Vajda, József y Ildikó Perjési-hámori. "Two dimensional mathematical model of heat-transmission in building structures". Pollack Periodica 2, n.º 3 (diciembre de 2007): 25–34. http://dx.doi.org/10.1556/pollack.2.2007.3.3.
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Steininger, Peter, Matthias Gaderer y Belal Dawoud. "Assessment of the Annual Transmission Heat Loss Reduction of a Refurbished Existing Building with an Advanced Solar Selective Thermal Insulation System". Sustainability 13, n.º 13 (30 de junio de 2021): 7336. http://dx.doi.org/10.3390/su13137336.
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A numerical parameter sensitivity analysis of the design parameters of the recently published solar selective thermal insulation system (SATIS) has been carried out to enhance its thermal and optical properties. It turned out that the insulation properties of SATIS can be effectively improved by reducing the length of the glass closure element. Increasing the area share of the light conducting elements (LCEs) and decreasing their length-to-diameter (L/D) ratio were identified as key parameters in order to increase the solar gain. Two SATIS variants were compared with the same wall insulation without SATIS in a yearly energetic performance assessment. The SATIS variant with 10 mm length of the closure element, 44.2% area share of LCE, as well as front and rear diameters of 12 mm/9 mm shows an 11.8% lower transmission heat loss over the heating period than the wall insulation without SATIS. A new methodology was developed to enable the implementation of the computed solar gains of SATIS in 1D simulation tools. The result is a radiant heat flow map for integration as a heat source in 1D simulation models. A comparison between the 1D and 3D models of the inside wall heat fluxes showed an integral yearly agreement of 98%.
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Yang, Chen, Long-jie Yu, Junhui Zhang y Jin-yuan Qian. "Cooling Performance Analysis of Outside Fins of the Closed Circuit Axial Piston Transmission". Machines 9, n.º 1 (16 de enero de 2021): 17. http://dx.doi.org/10.3390/machines9010017.
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Realizing conversion between fluid power and mechanical energy, the closed circuit axial piston transmission (CCAPT) plays a vital and indispensable role in miscellaneous industries. The frictional loss and leakage loss inside the system give rise to the inevitable temperature rise. In order to prolong the life of the device, a cooling structure on the outside of the CCAPT is designed for promoting heat dissipation. Based on the relevant heat transfer law and the temperature distribution of internal machinery elements, a spiral fin structure is designed at the shell side. With the help of numerical simulation, the effects of fin height, fin pitch, and fin thickness on the thermal performance are studied. The flow field and temperature field on the outside of the fin structure are obtained as a guidance for enhancing heat dissipation effect. Results indicate that the area of rotating elements tend to accumulate heat, where more attention should be paid for a better cooling effect. In addition to this, a moderate increase of fin height, fin pitch and fin thickness has a positive effect on heat transfer enhancement. The peak value of Nusselt number is obtained with a fin height of 7.5 mm, which is about 2.09 times that of the condition without the fin structure. An increase in fin pitch improves both heat transfer performance and comprehensive performance at the same. When fin pitch is 30 mm, Nusselt numberincreases 104% over the original condition.
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Masrura, Haque Mayeesha, Afsal Kareekunnan, Fayong Liu, Sankar Ganesh Ramaraj, Günter Ellrott, Ahmmed M. M. Hammam, Manoharan Muruganathan y Hiroshi Mizuta. "Design of Graphene Phononic Crystals for Heat Phonon Engineering". Micromachines 11, n.º 7 (30 de junio de 2020): 655. http://dx.doi.org/10.3390/mi11070655.
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Controlling the heat transport and thermal conductivity through a material is of prime importance for thermoelectric applications. Phononic crystals, which are a nanostructured array of specially designed pores, can suppress heat transportation owing to the phonon wave interference, resulting in bandgap formation in their band structure. To control heat phonon propagation in thermoelectric devices, phononic crystals with a bandgap in the THz regime are desirable. In this study, we carried out simulation on snowflake shaped phononic crystal and obtained several phononic bandgaps in the THz regime, with the highest being at ≈2 THz. The phononic bandgap position and the width of the bandgap were found to be tunable by varying the neck-length of the snowflake structure. A unique bandgap map computed by varying the neck-length continuously provides enormous amounts of information as to the size and position of the phononic bandgap for various pore dimensions. We have also carried out transmission spectrum analysis and found good agreement with the band structure calculations. The pressure map visualized at various frequencies validates the effectiveness of snowflake shaped nano-pores in suppressing the phonons partially or completely, depending on the transmission probabilities.
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Muzhaimey, Syarif Syahrul Syazwan, Nik Nazri Nik Ghazali, Mohd Zamri Zainon, Irfan Anjum Badruddin, Mohamed Hussien, Sarfaraz Kamangar y N. Ameer Ahammad. "Numerical Investigation of Heat Transfer Enhancement in a Microchannel with Conical-Shaped Reentrant Cavity". Mathematics 10, n.º 22 (18 de noviembre de 2022): 4330. http://dx.doi.org/10.3390/math10224330.
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The current study is focused on improving the thermal performance of the microchannel heat sink (MCHS) using the passive reentrant cavity approach. The MCHS physical model’s single channel was used in a three-dimensional numerical simulation. The basic geometrical layout of the MCHS’s computational domain was drawn from previously published research and verified using numerical and analytical correlations that were already in existence. The innovative conical-shaped microchannel heat sink’s (CMCHS) properties for heat transmission and fluid flow were examined numerically under steady-state conditions with laminar flow and a constant heat flux. At various flow velocities and configurations, the impacts of the geometrical parameters on pressure drops and heat transfer were examined. The outcome demonstrates a tremendously positive thermal performance with a significantly greater pressure drop than the traditional straight channel. In the microchannels with the conical-shaped reentrant cavities and minimal pressure loss, convection heat transfer is significantly improved. The findings of the present investigation demonstrate that the conical-shaped MCHS is practical and has a good chance of being used in real-world settings.
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Swing Gustafsson, Moa, Jonn Myhren y Erik Dotzauer. "Life Cycle Cost of Heat Supply to Areas with Detached Houses—A Comparison of District Heating and Heat Pumps from an Energy System Perspective". Energies 11, n.º 12 (23 de noviembre de 2018): 3266. http://dx.doi.org/10.3390/en11123266.
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There are different views on whether district heating (DH) or heat pumps (HPs) is or are the best heating solution in order to reach a 100% renewable energy system. This article investigates the economic perspective, by calculating and comparing the energy system life cycle cost (LCC) for the two solutions in areas with detached houses. The LCC is calculated using Monte Carlo simulation, where all input data is varied according to predefined probability distributions. In addition to the parameter variations, 16 different scenarios are evaluated regarding the main fuel for the DH, the percentage of combined heat and power (CHP), the DH temperature level, and the type of electrical backup power. Although HP is the case with the lowest LCC for most of the scenarios, there are alternatives for each scenario in which either HP or DH has the lowest LCC. In alternative scenarios with additional electricity transmission costs, and a marginal cost perspective regarding the CHP investment, DH has the lowest LCC overall, taking into account all scenarios. The study concludes that the decision based on energy system economy on whether DH should expand into areas with detached houses must take local conditions into consideration.
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Milan, Hugo F. M. y Kifle G. Gebremedhin. "General node for transmission-line modeling (TLM) method applied to bio-heat transfer". International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 31, n.º 5 (23 de mayo de 2018): e2455. http://dx.doi.org/10.1002/jnm.2455.
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Grabchak, E. P., E. L. Loginov y V. U. Chinaliev. "Digital transformation of Russia’s thermal power industry management system for optimization of consumers’ expenditures determined by tariffs and prices". Safety and Reliability of Power Industry 13, n.º 2 (31 de julio de 2020): 84–90. http://dx.doi.org/10.24223/1999-5555-2020-13-2-84-90.
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The development and implementation of a strategy for organizational reconfiguration of a digital heat and power super system to streamline the processes of providing structured technological zones with heat makes the basis for creating a coordinated system for optimizing the tariff and price load on heat and electricity consumers in the Russian economy. Providing the industry with a mechanism for regulating the processes of rendering heat energy services based on the transition to the system of Unified Heat-Supply Organizations (ETOs) and ensuring a return on price trend investment in the heat market with the possibility of transferring departmental reporting and analytics to a single regulatory legal basis enables regulating the operation of the power system as a subsystem of the Russian energy sector with a common information technology platform. It is proposed to develop a methodology for constructing mathematical estimates of reliability indicators of provided heat and power services in the form of analytical relationships and simulation models, taking into account the complex nature of the operation of electric power transmission and heat transportation networks as well as information systems that provide processing, storage and distribution of digital data and documents. The key activities are: development of a methodology for constructing mathematical estimates of reliability indicators of provided heat and power services in the form of analytical relationships and simulation models; development of digital methods for detecting hazardous effects; development of algorithms for storing information in the presence of natural and artificial interference; development of digital methods for optimization, modernization and transformation of production chains and processes, control models and planning procedures to neutralize threats to the reliability of provided heat and power services. The result should be the creation of a computer-based information system for modeling impacts on the electric and heat grid facilities.
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Sechenov, Pavel, Inna Rybenko y Valentin Tsymbal. "The calculation of thermodynamic functions for simulation model of the column string-emulsion reactor". Кибернетика и программирование, n.º 2 (febrero de 2020): 33–41. http://dx.doi.org/10.25136/2644-5522.2020.2.34102.
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The simulation model of the column string-emulsion reactor previously suggested that the temperature does not change on the height of reactor and over time is consistent. The assessment of temperature changes in the reactor requires the knowledge on the amount of heat necessary to heat up the particles, absorbed or emitted in the course of chemical reactions, as well as the speed of heat transmission in space. The possibility of calculating these parameters for each floating particle in online regime is limited by the operating speed of the computer system. For accelerating the calculations, the author creates the database of these parameters for all substances involved in the reactions. In these circumstances, enthalpies and entropies were expressed in through the specific thermal capacity calculated based on the fifth degree polynomial. The coefficient values of the polynomial and phase transitions were taken from the reference books. The article provides an algorithm in form of the logic diagram for calculating the specific enthalpy of the particle. Based on the developed algorithm, the author creates the software that allows calculating thermodynamic functions. The interaction between the classes are demonstrated in the UML class diagram. The research presents the calculations of specific enthalpy and entropy for substances in the interval of temperatures of 298-1850 K. Variations of the values of enthalpy and entropy at the temperature of 1700 K compared to the reference values do not exceed 1.2 %.
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Ostroushko, Mykola, André Buchau y Wolfgang Rucker. "Design and simulation of the electromagnetic heating of a biological tissue". COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 36, n.º 2 (6 de marzo de 2017): 408–16. http://dx.doi.org/10.1108/compel-05-2016-0220.
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Purpose The purpose of this paper is to present the design and the numerical calculation of the electromagnetic heating system for the ablation therapy. Hence, the heating of the tumor cells must be processed very carefully to achieve a localized coagulative necrosis and to avoid too high temperatures inside the tissue. Design/methodology/approach The non-invasive method of the ablation therapy is implemented due to the inductive power transmission between the generator and implant. The ferromagnetic implant has a small size and can be placed intravenously into tumor cells. High-frequency driving currents are necessary to obtain high induced eddy currents within the ferromagnetic implant. Findings Finite element analysis has been used for the design and numerical calculation of the electromagnetic heating system. The electromagnetic analysis is done in the time domain due to the nonlinearity of the ferromagnetic implant. Magnetic fields are computed based on a magnetic vector potential formulation. The thermal analysis is done in the time domain as well. The temperature computation in biological tissue is based on a heat balance equation. Research limitations/implications This paper is focused on the design and simulation of the inductive system for the ablation therapy. Practical implications The designed system can be practically implemented. It can be used for the clinical study of the immune response by the thermal ablation therapy. Originality/value The common method of thermal ablation is combined with an inductive power transmission. It enables a repetitive application of this method to study the immune response.
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Bagheri, Hamed, Mohammadali Behrang, Ehsanolah Assareh, Mohsen Izadi y Mikhail A. Sheremet. "Free Convection of Hybrid Nanofluids in a C-Shaped Chamber under Variable Heat Flux and Magnetic Field: Simulation, Sensitivity Analysis, and Artificial Neural Networks". Energies 12, n.º 14 (22 de julio de 2019): 2807. http://dx.doi.org/10.3390/en12142807.
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In the present investigation, the free convection energy transport was studied in a C-shaped tilted chamber with the inclination angle α that was filled with the MWCNT (MultiWall Carbon Nanotubes)-Fe3O4-H2O hybrid nanofluid and it is affected by the magnetic field and thermal flux. The control equations were numerically resolved by the finite element method (FEM). Then, using the artificial neural network (ANN) combined with the particles swarm optimization algorithm (PSO), the Nusselt number was predicted, followed by investigating the effect of parameters including the Rayleigh number (Ra), the Hartmann number (Ha), the nanoparticles concentration (φ), the inclination angle of the chamber (α), and the aspect ratio (AR) on the heat transfer rate. The results showed the high accuracy of the ANN optimized by the PSO algorithm in the prediction of the Nusselt number such that the mean squared error in the ANN model is 0.35, while in the ANN model, it was optimized using the PSO algorithm (ANN-PSO) is 0.22, suggesting the higher accuracy of the latter. It was also found that, among the studied parameters with an effect on the heat transfer rate, the Rayleigh number and aspect ratio have the greatest impact on the thermal transmission intensification. The obtained data also showed that a growth of the Hartmann number illustrates a reduction of the Nusselt number for high Rayleigh numbers and the heat transfer rate is almost constant for low Rayleigh number values.
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Liu, Feng Xia, Wei Wei, Zhi Jun Liu, Tao Tian Leng y Zhi Yi Li. "Hydrodynamic Modeling of Dense Granular Flow between Two Waved Plates". Advanced Materials Research 550-553 (julio de 2012): 3201–5. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.3201.
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Using a two-dimensional Discrete Element Method (DEM) computer simulation, dense granular flows with the particle size range of 2-3 mm were studied between two vertical waved plates. The hydrodynamic characteristics, such as flow pattern, distribution of stress, velocity and trajectory of particles were analyzed in the process of granular flow. The results were compared to those of the flows between two vertical flat plates. The results indicated that the transient stress between waved plates was heterogeneous; the zigzag-like pressure profiles on the waved pate increased. Conclusions could be drawn that the formation of dense particle clusters disturbed spatial homogeneity and resulted in collisional anisotropy which was propitious to enhance the process of momentum, heat and mass transmission.
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Wang, Baoguo, Minghua Fu y Longya Xu. "EVALUATION AND COMPUTER SIMULATION OF A TRANSCUTANEUOUS ENERGY TRANSMISSION SYSTEM FOR ARTIFICIAL HEART AND VENTRICULAR ASSIST SYSTEM". ASAIO Journal 45, n.º 2 (marzo de 1999): 172. http://dx.doi.org/10.1097/00002480-199903000-00213.
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Kuczyński, Szymon, Mariusz Łaciak, Andrzej Olijnyk, Adam Szurlej y Tomasz Włodek. "Thermodynamic and Technical Issues of Hydrogen and Methane-Hydrogen Mixtures Pipeline Transmission". Energies 12, n.º 3 (12 de febrero de 2019): 569. http://dx.doi.org/10.3390/en12030569.
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The use of hydrogen as a non-emission energy carrier is important for the innovative development of the power-generation industry. Transmission pipelines are the most efficient and economic method of transporting large quantities of hydrogen in a number of variants. A comprehensive hydraulic analysis of hydrogen transmission at a mass flow rate of 0.3 to 3.0 kg/s (volume flow rates from 12,000 Nm3/h to 120,000 Nm3/h) was performed. The methodology was based on flow simulation in a pipeline for assumed boundary conditions as well as modeling of fluid thermodynamic parameters for pure hydrogen and its mixtures with methane. The assumed outlet pressure was 24 bar (g). The pipeline diameter and required inlet pressure were calculated for these parameters. The change in temperature was analyzed as a function of the pipeline length for a given real heat transfer model; the assumed temperatures were 5 and 25 °C. The impact of hydrogen on natural gas transmission is another important issue. The performed analysis revealed that the maximum participation of hydrogen in natural gas should not exceed 15%–20%, or it has a negative impact on natural gas quality. In the case of a mixture of 85% methane and 15% hydrogen, the required outlet pressure is 10% lower than for pure methane. The obtained results present various possibilities of pipeline transmission of hydrogen at large distances. Moreover, the changes in basic thermodynamic parameters have been presented as a function of pipeline length for the adopted assumptions.
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Ullah, Zia, Nevzat Akkurt, Haifaa F. Alrihieli, Sayed M. Eldin, Aisha M. Alqahtani, Abid Hussanan, Muhammad Ashraf y Mah Jabeen. "Temperature-Dependent Density and Magnetohydrodynamic Effects on Mixed Convective Heat Transfer along Magnetized Heated Plate in Thermally Stratified Medium Using Keller Box Simulation". Applied Sciences 12, n.º 22 (11 de noviembre de 2022): 11461. http://dx.doi.org/10.3390/app122211461.
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The heat transmission properties along the non-magnetized geometries have been numerically obtainedby various researchers. These mechanisms are less interesting in engineering and industrial processes because of excessive heating. According to current studies, the surface is magnetized and the fluid is electrically conductive, which helps to lessen excessive surface heating. The main objective of the current analysis is to numerically compute the temperature-dependent density effect on magnetohydrodynamic convective heat-transfer phenomena of electrical-conductive fluid flow along the vertical magnetized and heated plate placed in a thermally stratified medium. For the purpose of numerical analysis, the theoretical process governing heat and magnetic intensity along a vertical magnetic plate is examined. By using suitable and well-known similarity transformations for integration, the non-linear coupled PDEs for the aforementioned electrical-conductive fluid flow mechanism are changed and subsequently converted into non-similar formulation. The Keller Box method is used to numerically integrate the final non-similar equations. The MATLAB software program plots the transformed algebraic equations graphically and quantitatively. The behavior of the physical quantities such asvelocity graph, magnetic field graph, and temperature plot along with their slopes that arerate of skin friction, the rate of heat transfer, and the rate of magnetic intensity for different parameters included in the flow model. The novelty of the current work is to compute the magneto-thermo analysis of electrically conducting flow along the vertical symmetric heated plate. First, we secure the numerical solution for steady part and then these results are used to find skin friction, heat transfer, and magnetic intensity. In the current work, the fluid becomes electrically conducing due to a magnetized surface which insulates heat during the mechanism and reduces the excessive heating. The results are excellent and accurate because they are satisfied by its given boundary conditions. Additionally, the current problems have a big impact on the production of polymer materials, glass fiber, petroleum, plastic films, polymer sheets, heat exchangers, catalytic reactors, and electronic devices.
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Wai, Thiri Shoon, Naoki Maruyama, Yuttana Mona y Chatchawan Chaichana. "Prediction of the Energy Consumption for Indoor Strawberry Cultivation in a Tropical Climate". Journal of Hunan University Natural Sciences 49, n.º 3 (28 de marzo de 2022): 158–67. http://dx.doi.org/10.55463/issn.1674-2974.49.3.17.
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This article addresses the lack of information for predicting the energy consumption of strawberry plantations inside plant factories located in tropical climate regions. This study aims to investigate the energy consumption of the cultivation of strawberries in the controlled environment room and to develop a TRNSYS computer model for the controlled environment room. Experiments were conducted in a 25 m3 controlled environment room. There are 180 strawberry trees inside the room. Light Emitting Diode (LED) grow light substitutes for natural sunlight. An air conditioner was used to regulate the indoor air condition. A computer model was developed using TRNSYS (TRaNsientSYStem simulation tool) and was validated using the collected data. There are three main components of the room heat load: transmission, lighting, and evapotranspiration. The lighting heat load shares more than 96% of the total heat load — the evapotranspiration load increases when the LED turns on. However, the lighting consumes only about 36% of total electricity consumption, while the air conditioner consumes 64%. Most of the electricity is used during the runner stage. Electricity consumption can be saved by 40% if the runners are grown outside the plant factory. Therefore, the high heat load is a feature in the plant factory. In this study, the lighting heat load is the most significant parameter. The strawberry light intensity requirement is the high lighting heat load. Consequently, the electricity for the air conditioner becomes high since the air conditioner removes the generated heat from the high light intensity. Therefore, the air conditioner electricity consumption is enormous in this study. Moreover, the required lighting intensity, photoperiod, and low air temperature factors affect electricity consumption. Therefore, the results from this study could provide strategies for energy cost reduction and plantation management for plant factories cultivation.
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M., Anugraha y Dr Krishnaveni S.H. "In Mobile Adhoc Networks, a Trustworithness of Data Transmission Using HTCMR". Webology 19, n.º 1 (20 de enero de 2022): 2152–63. http://dx.doi.org/10.14704/web/v19i1/web19145.
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Mobile Ad hoc Network is a self-configured network, the main responsibility faced in the network is security. Malicious nodes are mostly to blame for the insecurity of MANET. The malicious attacker nodes will disrupt the overall functioning of the network, and many security solution approaches are utilized for safe and reliable communication in MANET to stop such harmful activity. This routing, known as Hybrid Trust Cluster based Multiple Routing (H-TCMR), helps to minimize the amount of messages carried inside the network, lowering the network's total energy usage. It utilizes Hybrid Time Division Multiple Access (HTDMA) for time slots and the Unified Slot Assignment Protocol (USAP) for cluster allocation. Using Hybrid Rider Optimization Algorithm (HROA) approaches, a group of riders will drive together to a specified location in order to obtain the cluster head slot. The suggested approach encrypts the data before sending it to its final destination. It also helps to extend the life of mobile networks. Some of the factors considered in simulation studies include connection, energy, average delay, throughput, as well as overall cluster quality. The simulation result demonstrates a performance study of HTCMR's dependable security, as well as increased system efficiency and improved data transfer security.
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Lee, Soonmyung y Sanghoon Park. "Zero-Energy Building Integrated Planning Methodology for Office Building Considering Passive and Active Environmental Control Method". Applied Sciences 11, n.º 8 (19 de abril de 2021): 3686. http://dx.doi.org/10.3390/app11083686.
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The objective of this study is to derive a design methodology for a zero-energy building considering the energy production and consumption of the building. In order to establish the design methodology, various factors affecting the energy production and consumption of the building are derived, and the effect of the heat transmission rate, the surface to volume ratio (S/V ratio), the location and the orientation of the building are analyzed by simulation method. As a result, the S/V ratio and the heat transmission rate are the most important factors in the central region of Korea where consumes large amounts of heating and cooling energy. This is because the final energy consumption varies depending on the heat loss through the envelope. It was confirmed that solar power generation is the most important factor in the southern regions of Korea where the energy consumption is relatively small. The final energy consumption varies depending on the solar power generation in these areas. Therefore, when designing a zero-energy building, the zero-energy of the building can be achieved by using the design methodology established in this study.
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De Schutter, E., J. D. Angstadt y R. L. Calabrese. "A model of graded synaptic transmission for use in dynamic network simulations". Journal of Neurophysiology 69, n.º 4 (1 de abril de 1993): 1225–35. http://dx.doi.org/10.1152/jn.1993.69.4.1225.
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1. The heartbeat central pattern-generating network of the medicinal leech contains elemental neural oscillators, comprising reciprocally inhibitory pairs of segmental heart interneurons, that use graded as well as spike-mediated synaptic transmission. We are in the process of developing a general computer model of this pattern generator. Our modeling goal is to explore the interaction of membrane currents and synaptic transmission that promote oscillation in heart interneurons. As a first step toward this goal, we have developed a computer model of graded synaptic transmission between reciprocally inhibitory heart interneurons. Previously gathered voltage-clamp data of presynaptic Ca2+ currents and simultaneous postsynaptic currents and potentials (5 mM external [Ca2+]) were used as the bases of the model. 2. We assumed that presynaptic Ca2+ current was composed of distinct fast (ICaF) and slow (Icas) components because there are two distinct time courses of inactivation for this current. We fitted standard Hodgkin-Huxley equations (Eq. 1 and 2, APPENDIX) to these components using first-order activation and inactivation kinetics. 3. Graded synaptic transfer in the model is based on calculation of a dimensionless variable [P]. A portion of both IcaF and ICaS determined by a factor A contributes to [P], and a removal factor B decreases [P] (Eq. 4, APPENDIX). [P] can be roughly equated to the [Ca2+] in an unspecified volume that is effective in causing transmitter release. Transmitter release, and thus postsynaptic conductance, is related to [P]3 (Eq. 3, APPENDIX). 4. We adapted our model to voltage-clamp data gathered at physiological external [Ca2+] (2.0 mM) and tested it for shorter presynaptic voltage steps. Presynaptic Ca2+ currents and synaptic transfer were well simulated under all conditions. 5. The graded synaptic transfer model could be used in a network simulation to reproduce the oscillatory activity of a reciprocally inhibitory pair of heart interneurons. Because synaptic transmission in the model is an explicit function of presynaptic Ca2+ current, the model should prove useful to explore the interaction between membrane currents and synaptic transmission that promote and modulate oscillation in reciprocally inhibitory heart interneurons.
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Cheim, Luiz y Alan F. Howe. "The use of transmission-line modelling (TLM) for the solution of heat diffusion in electric fuses". International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 5, n.º 4 (noviembre de 1992): 289–95. http://dx.doi.org/10.1002/jnm.1660050409.
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Orgeira-Crespo, Pedro, Carlos Ulloa, José M. Núñez y José A. Pérez. "Development of a Transient Model of a Lightweight, Portable and Flexible Air-Based PV-T Module for UAV Shelter Hangars". Energies 13, n.º 11 (5 de junio de 2020): 2889. http://dx.doi.org/10.3390/en13112889.
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This research paper introduces a mathematical model to predict the performance of photovoltaic–thermal systems (PV-T), based on a thin layer flexible panel and an air pipe, by using the Trnsys® software tool to simulate energetic systems. The main advantage of these types of panels is their easy portability, making them ideal to address thermal needs in several scenarios. In the military field, there is an important concern about the use of sustainable energy; for instance, cooling facilities for infantry tents used in their deployments. In this research, a PV-T panel to cover electrical power needs for an infantry’s hangar unmanned air vehicle (UAV) is introduced. The proposed thermal model, based on the novelty of inertial mass (lump) as an approach to real panel behavior, has been validated through the comparison between Trnsys’ model simulation data, a real weather station, and data obtained in a test bed. Genopt’s simulation software is used to fit the model, allowing for the prediction of heat transmission coefficient values. The good match between simulated and experimental data makes the proposed model suitable for the photovoltaic–thermal prediction of panel behavior.
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Xu, Qiwei, Yunqi Mao, Meng Zhao y Shumei Cui. "A Hybrid Electric Vehicle Dynamic Optimization Energy Management Strategy Based on a Compound-Structured Permanent-Magnet Motor". Energies 11, n.º 9 (23 de agosto de 2018): 2212. http://dx.doi.org/10.3390/en11092212.
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A dynamic optimization energy management strategy called Hybrid Electric Vehicle Based on Compound Structured Permanent-Magnet Motor (CSPM-HEV) is investigated in this paper. CSPM-HEV has obvious advantages in power density, heat dissipation efficiency, torque performance and energy transmission efficiency. This paper describes the topology and working principle of the CSPM-HEV, and analyzes its operating mode and corresponding energy flow laws. On this basis, the relationship about the power loss of the vehicle, the CSPM transmission ratio iCSPM and the CSPM-HEV power distribution coefficient f1 were derived. According to the optimal combination of (iCSPM, f1), the engine power and speed which minimize the power loss of the vehicle, were calculated, thus realizing the instantaneous optimal control of the vehicle. In addition, in order to improve the instantaneously optimized control processing speed, a neural network controller was established. The drive axle demand power, speed and battery State of Charge (SOC), were taken as input variables. Then, the engine power and speed were taken as output variables. The simulation results show that the average speed of the instantaneous optimization strategy after BP neural network optimization is increased by 98.1%, the control effect is significant, and it has high application value.
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Kim, Myeongjin y Fernando Bello. "Multi-Shape Free-Form Deformation Framework for Efficient Data Transmission in AR-Based Medical Training Simulators". Applied Sciences 11, n.º 21 (24 de octubre de 2021): 9925. http://dx.doi.org/10.3390/app11219925.
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Augmented reality medical training simulators can provide a realistic and immersive experience by overlapping the virtual scene on to the real world. Latency in augmented reality (AR) medical training simulators is an important issue as it can lead to motion sickness for users. This paper proposes a framework that can achieve real-time rendering of the 3D scene aligned to the real world using a head-mounted display (HMD). Model deformation in the 3D scene is categorised into local deformation derived from user interaction and global deformation determined by the simulation scenario. Target shapes are predefined by a simulation scenario, and control points are placed to embed the predefined shapes. Free-form deformation (FFD) is applied to multiple shapes to efficiently transfer the simulated model to the HMD. Global deformation is computed by blending a mapping matrix of each FFD with an assigned weighting value. The local and global deformation are then transferred through the control points updated from a deformed surface mesh and its corresponding weighting value. The proposed framework is verified in terms of latency caused by data transmission and the accuracy of a transmitted surface mesh in a vaginal examination (VE) training simulation. The average latency is reduced to 7 ms, less than the latency causing motion sickness in virtual reality simulations. The maximum relative error is less than 3%. Our framework allows seamless rendering of a virtual scene to the real world with substantially reduced latency and without the need for an external tracking system.
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Jin, Liqiang, Xianglong Peng, Dehai Wang, Desheng Guo y Biao Chen. "Calculation and Verification of the Real-Time Working Characteristics of a Viscous Coupling". Applied Sciences 11, n.º 3 (26 de enero de 2021): 1110. http://dx.doi.org/10.3390/app11031110.
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During operation, the shear friction between the silicone oil and the plates of a viscous coupling (VC) will generate heat and increase the temperature of the silicone oil, inflate the volume, increase the internal pressure, and eventually deliver more torque, in what is called hump operation mode. Temperature is the root cause of the change of the operation characteristics in VCs. In this paper, the heat-transfer model for a VC is established based on the thermodynamical theory. The capacity of the heat transmission of each part of the VC are calculated to obtain the temperature of silicone oil. The real-time shear torque of the VC is finally obtained. Then, the theoretical analysis on hump phenomenon was done. The internal pressure was obtained by analyzing the characteristics of ideal gas, and the maximum torque during the hump phenomenon was calculated. The simulation of the key parameters and the entire working process for the VC were carried out based on the proposed calculation model. A prototype of a viscous limited-slip differential (VLSD) was developed to test the output torque characteristics. The test results were quite consistent with the simulation results, and the accuracy of the calculation model was verified.
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Yu, Tsu-Ping, Yung-Lung Lee, Ya-We Li y Shih-Wei Mao. "The Study of Cooling Mechanism Design for High-Power Communication Module with Experimental Verification". Applied Sciences 11, n.º 11 (3 de junio de 2021): 5188. http://dx.doi.org/10.3390/app11115188.
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With the continued development of 5G mobile communications technology, the implementation of high-power communication systems has become a key indicator of developed nations. Communication modules are also trending toward wide bandwidth and high-capacity Multi-Input and Multi-Output systems. As the signal transmission speed and resolution continue with the increasing trend, the power used to operate these communications systems increase, causing extreme heat generation by transmit/receive modules (T/R module). In conditions where computation load increases in micro design systems, chips must operate in environments that are narrow, sealed, and have no convection, which can drastically increase the thermal load within a system. If no proper cooling system is utilized, the system fails or operates at impacted performance due to excessive temperatures. To solve the aforementioned problem, this study aimed to optimize the design of the cooling system in the T/R modules of communications systems by integrating heat pipes, cooling fans, cooling fins, and cooling chips within a limited space. We also proposed four types of cold plates based on the different directional clamp-in configuration methods of heat pipes within copper panels and utilized the finite element method to simulate and analyze the heat dissipation performance. The simulation results reveal that cold plates of types I and II can achieve a better heat dissipation performance. Finally, types I and II cold plates were selected for production and experimental verification. The results show that heat dissipation performances were similar to simulation results. The results also confirmed that type II cold plate has a better temperature uniformity and heat transfer efficiency. Thus, the cooling mechanism depicted in this study is viable in practical applications. The proposed mechanisms can also provide a reference for heat dissipation design patterns in different electronic module settings.
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P. Saveetha, P. Saveetha, Y. Harold Robinson P. Saveetha, Vimal Shanmuganathan Y. Harold Robinson, Seifedine Kadry Vimal Shanmuganathan y Yunyoung Nam Seifedine Kadry. "Hybrid Energy-based Secured Clustering technique for Wireless Sensor Networks". 網際網路技術學刊 23, n.º 1 (enero de 2022): 021–31. http://dx.doi.org/10.53106/160792642022012301003.
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<p>The performance of the Wireless sensor networks (WSNs) identified as the efficient energy utilization and enhanced network lifetime. The multi-hop path routing techniques in WSNs have been observed that the applications with the data transmission within the cluster head and the base station, so that the intra-cluster transmission has been involved for improving the quality of service. This paper proposes a novel Hybrid Energy-based Secured Clustering (HESC) technique for providing the data transmission technique for WSNs to produce the solution for the energy and security problem for cluster based data transmission. The proposed technique involves the formation of clusters to perform the organization of sensor nodes with the multi-hop data transmission technique for finding the specific node to deliver the data packets to the cluster head node and the secured transmission technique is used to provide the privacy of the sensor nodes through the cluster. The residual energy of the sensor nodes is another parameter to select the forwarding node. The simulation results can show the efficiency of this proposed technique in spite of lifetime within the huge amount data packets. The security of this proposed technique is measured and increases the performance of the proposed technique.</p> <p> </p>
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Bošanský, Michal y Bořek Patzák. "Different Approaches to Parallelization of Vector Assembly". Applied Mechanics and Materials 821 (enero de 2016): 341–48. http://dx.doi.org/10.4028/www.scientific.net/amm.821.341.
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Recent developments in computer hardware bring in new opportunities in numerical mod-elling. Traditional simulation codes run sequentially on computers with a single processing unit,where only one instruction can be processed at any moment in time. The performance of single pro-cessing units is reaching the physical limits, given by transmission delays and heat build-up on thesilicon chips. The current trend in technology is parallel processing, relying on the simultaneous useof multiple processing units to solve given problem. The efficient utilization of parallel computingresources requires development of new algorithms and techniques allowing to decompose the giventask into pieces of work that can be processed simultaneously.This contribution focuses on parallelization of vector assembly operation, which is one of thecritical operations in any finite element software. The aim of presented work is to propose differentapproaches to parallelization of this operation and to evaluate their efficiency. In this contribution,we focus on shared memory programming model, where individual processes/tasks share a commonaddress space, which they read and write to asynchronously. Open Multi-Processing (OpenMP) andPortable Operating System Interface (POSIX) Threads programming models are used to implementdifferent variants of parallel assembly operations. The efficiency of implemented approaches is eval-uated on a selected benchmark problem, comparing computation times and obtained speed-ups.
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Száva, Renáta-Ildikó, Ioan Száva, Sorin Vlase, Pál-Botond Gálfi, Károly Jármai, Teofil Gălățeanu, Gabriel Popa y Zsolt Asztalos. "Modern Dimensional Analysis-Based Steel Column Heat Transfer Evaluation Using Multiple Experiments". Symmetry 14, n.º 9 (19 de septiembre de 2022): 1952. http://dx.doi.org/10.3390/sym14091952.
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In order to foresee the response during the fire of a real symmetrical structure (prototype), nowadays engineers apply methods which involve the associated reduced-scale model’s behaviors, mainly dimensional analysis behaviors. Between the dimensional analysis methods, the so-called Modern Dimensional Analysis (MDA), developed by Szirtes, fulfills all engineering requirements compared with the classical one. The authors used this new proposed method to describe their original electric fire simulation testing bench, as well as the Model Law (using MDA) for the heat transfer in tubular rectangular bars. So, a validation of the Model Law was performed based on several scrupulous experimental investigations both on a real column’s segment and its associated reduced-scale models manufactured at 1:2; 1:4, as well as 1:10 scales. The original heating system, the elaborated protocol, the deduced Model Law, and the results of the experimental investigations represent the contributions of the authors in the field of metallic structures subject to fires. The results validate the possibility of using MDA in the case of heat transmission.
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Padmaja, P. y G. V. Marutheswar. "Certain Investigation on Secured Data Transmission in Wireless Sensor Networks". International Journal of Mobile Computing and Multimedia Communications 8, n.º 1 (enero de 2017): 48–61. http://dx.doi.org/10.4018/ijmcmc.2017010104.
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Wireless Sensor Network (WSN) need to be more secure while transmitting data as well as should be deployed properly to reduce redundancy and energy consumption. WSNs suffer from many constraints, including low computation capability, small memory, limited energy resources, susceptibility to physical capture and the use of insecure wireless communication channels. These constraints make security in WSNs a challenge. In this paper, a survey of security issues in WSNs is presented and a new algorithm TESDA is proposed, which is an optimized energy efficient secured data aggregation technic. The cluster head is rotated based on residual energy after each round of aggregation so that network lifetime increases. Based on deviation factor calculated, the trust weight is assigned, if more deviation, then the trust value is less. Simulation results observed by using NS-2. From network animator and x-graphs the result are analyzed. Among all protocols tesda is an energy efficient secured data aggregation method.
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Muramatsu, Dairoku y Ken Sasaki. "Transmission Analysis in Human Body Communication for Head-Mounted Wearable Devices". Electronics 10, n.º 10 (19 de mayo de 2021): 1213. http://dx.doi.org/10.3390/electronics10101213.
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As society ages, wireless body area networks (WBANs) are expected to increasingly improve the quality of life of the elderly and disabled. One promising WBAN technology is human body communication (HBC), which utilizes part of the human body as a transmission medium. Communication between head-mounted wearable devices, such as hearing aids, is a potential HBC application. To clarify the HBC transmission mechanism between head-mounted wearable devices, this study analyzes the input impedance characteristics of the transceiver electrodes, transmission characteristics, and electric field distributions around and through a detailed head model. The investigation was performed via an electromagnetic field simulation. The signal frequency had less effect on the transmission characteristics and electric field distributions at 10, 20, and 30 MHz. However, the transmission mechanism between the head-mounted wearable devices was influenced by the number of electrodes in the transceiver. Moreover, the transmission characteristics between two-electrode transceivers were improved by impedance matching. Finally, the availability of the proposed system was evaluated from power consumption and human safety perspectives.
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Yu, Xiao, Shijian Zhang, Ivan Sergeevich Egorov, Jiangqi Zhao, Chang Xiong, Sha Yan, Chang Tan, Gennady Efimovich Remnev y Xiaoyun Le. "Optimization of Transmission X-ray Target for Intense Pulsed Electron Beam Accelerators". Applied Sciences 12, n.º 9 (25 de abril de 2022): 4327. http://dx.doi.org/10.3390/app12094327.
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X-ray sources based on pulsed electron accelerators stimulate the development of bremsstrahlung converter designs. The numerical optimization of transmission-type X-ray targets for maximum X-ray output by pulsed electron beams was carried out in the present work. The targets featured a combination of a heavy element (tungsten or molybdenum) X-ray conversion layer and a titanium membrane that served as the vacuum window, thermal shielding for converter heat, and an electron dump. The energy spectrum of the electron beam generated via explosive emission was analyzed via the space-charge effect, and was utilized for the source sampling algorithm for electron transportation simulation with a Monte Carlo method for X-ray emission analysis. It was revealed that the transmission photon intensity of a mono-material target is primarily affected by the thickness of the target, and there exists an optimal target thickness within which the photon fluence is restricted by insufficient electron stopping; when exceeded, the extra thickness of the X-ray converter target imposes absorption and attenuates the generated X-ray. Analysis on dual-layer targets proved that this optimized converter target thickness, combined with a proper titanium window, produces the highest X-ray photon emissions.
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Yu, Xiao, Shijian Zhang, Ivan Sergeevich Egorov, Jiangqi Zhao, Chang Xiong, Sha Yan, Chang Tan, Gennady Efimovich Remnev y Xiaoyun Le. "Optimization of Transmission X-ray Target for Intense Pulsed Electron Beam Accelerators". Applied Sciences 12, n.º 9 (25 de abril de 2022): 4327. http://dx.doi.org/10.3390/app12094327.
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X-ray sources based on pulsed electron accelerators stimulate the development of bremsstrahlung converter designs. The numerical optimization of transmission-type X-ray targets for maximum X-ray output by pulsed electron beams was carried out in the present work. The targets featured a combination of a heavy element (tungsten or molybdenum) X-ray conversion layer and a titanium membrane that served as the vacuum window, thermal shielding for converter heat, and an electron dump. The energy spectrum of the electron beam generated via explosive emission was analyzed via the space-charge effect, and was utilized for the source sampling algorithm for electron transportation simulation with a Monte Carlo method for X-ray emission analysis. It was revealed that the transmission photon intensity of a mono-material target is primarily affected by the thickness of the target, and there exists an optimal target thickness within which the photon fluence is restricted by insufficient electron stopping; when exceeded, the extra thickness of the X-ray converter target imposes absorption and attenuates the generated X-ray. Analysis on dual-layer targets proved that this optimized converter target thickness, combined with a proper titanium window, produces the highest X-ray photon emissions.
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Gheitaghy, A. M., B. Takabi y M. Alizadeh. "Modeling of ultrashort pulsed laser irradiation in the cornea based on parabolic and hyperbolic heat equations using electrical analogy". International Journal of Modern Physics C 25, n.º 09 (26 de agosto de 2014): 1450039. http://dx.doi.org/10.1142/s0129183114500399.
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Hyperbolic and parabolic heat equations are formulated to study a nonperfused homogeneous transparent cornea irradiated by high power and ultrashort pulsed laser in the Laser Thermo Keratoplasty (LTK) surgery. Energy absorption inside the cornea is modeled using the Beer–Lambert law that is incorporated as an exponentially decaying heat source. The hyperbolic and parabolic bioheat models of the tissue were solved by exploiting the mathematical analogy between thermal and electrical systems, by using robust circuit simulation program called Hspice to get the solutions of simultaneous RLC and RC transmission line networks. This method can be used to rapidly calculate the temperature in laser-irradiated tissue at time and space domain. It is found that internal energy gained from the irradiated field results in a rapid rise of temperature in the cornea surface during the early heating period, while the hyperbolic wave model predicts a higher temperature rise than the classical heat diffusion model. In addition, this paper investigates and examines the effect of some critical parameters such as relaxation time, convection coefficient, radiation, tear evaporation and variable thermal conductivity of cornea. Accordingly, it is found that a better accordance between hyperbolic and parabolic models will be achieved by time.
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Zhai, Li, Guangyuan Zhong, Yu Cao, Guixing Hu y Xiang Li. "Research on Magnetic Field Distribution and Characteristics of a 3.7 kW Wireless Charging System for Electric Vehicles under Offset". Energies 12, n.º 3 (27 de enero de 2019): 392. http://dx.doi.org/10.3390/en12030392.
Texto completoResumen
A 3.7 kW resonant wireless charging system (WCS) is proposed to realize the energy transmission for electric vehicles. In addition to designing the electrical modules functionally, coupling coils are designed and verified by physical prototype, which guarantees the accuracy of coils and subsequent simulations. Then, we focus on the magnetic field distribution of coupling coils in the vehicle environment. Four points (A1, A2, A3, A4) in different regions and three points (the head B1, chest B2 and cushion B3) in the driving seat are helped to measure the magnetic field strength. The magnetic field distribution of coils under five offsets of 60 mm, 120 mm, 180 mm, 240 mm and 300 mm are analyzed theoretically and simulated correspondingly. The simulation results indicate that the magnetic field strength of test points are within the limits, but the strength at A3 is larger than 30.4 A/m required by SAE J2954 at 40% offset and 50% offset. Taking into account the composition of the actual magnetic field, the magnetic field distribution due to side-band and odd harmonic current are also obtained. An experimental bench for the proposed 3.7 kW WCS is built to validate the rightness and feasibility of the simulated scheme. The results of simulation and experiments of magnetic field distribution have less error and are often in good agreement.
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Ji, Xiang, Huiqun Yu, Guisheng Fan, Huaiying Sun y Liqiong Chen. "Efficient and Reliable Cluster-Based Data Transmission for Vehicular Ad Hoc Networks". Mobile Information Systems 2018 (30 de julio de 2018): 1–15. http://dx.doi.org/10.1155/2018/9826782.
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Vehicular ad hoc network (VANET) is an emerging technology for the future intelligent transportation systems (ITSs). The current researches are intensely focusing on the problems of routing protocol reliability and scalability across the urban VANETs. Vehicle clustering is testified to be a promising approach to improve routing reliability and scalability by grouping vehicles together to serve as the foundation for ITS applications. However, some prominent characteristics, like high mobility and uneven spatial distribution of vehicles, may affect the clustering performance. Therefore, how to establish and maintain stable clusters has become a challenging problem in VANETs. This paper proposes a link reliability-based clustering algorithm (LRCA) to provide efficient and reliable data transmission in VANETs. Before clustering, a novel link lifetime-based (LLT-based) neighbor sampling strategy is put forward to filter out the redundant unstable neighbors. The proposed clustering scheme mainly composes of three parts: cluster head selection, cluster formation, and cluster maintenance. Furthermore, we propose a routing protocol of LRCA to serve the infotainment applications in VANET. To make routing decisions appropriate, we nominate special nodes at intersections to evaluate the network condition by assigning weights to the road segments. Routes with the lowest weights are then selected as the optimal data forwarding paths. We evaluate clustering stability and routing performance of the proposed approach by comparing with some existing schemes. The extensive simulation results show that our approach outperforms in both cluster stability and data transmission.
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Veeram, Gopinath, Pasam Poojitha, Harika Katta, Sanakkayala Hemalatha, Macherla Jayachandra Babu, Chakravarthula S. K. Raju, Nehad Ali Shah y Se-Jin Yook. "Simulation of Dissipative Hybrid Nanofluid (PEG-Water + ZrO2 + MgO) Flow by a Curved Shrinking Sheet with Thermal Radiation and Higher Order Chemical Reaction". Mathematics 10, n.º 10 (16 de mayo de 2022): 1706. http://dx.doi.org/10.3390/math10101706.
Texto completoResumen
The heat transmission capabilities of hybrid nanofluids are superior to those of mono nanofluids. In addition to solar collectors and military equipment, they may be found in a number of areas including heat exchanger, automotive industry, transformer cooling and electronic cooling. The purpose of this study was to evaluate the significance of the higher order chemical reaction parameter on the radiative flow of hybrid nanofluid (polyethylene glycol (PEG)–water combination: base fluid and zirconium dioxide, magnesium oxide: nanoparticles) via a curved shrinking sheet with viscous dissipation. Flow-driven equations were transformed into nonlinear ODEs using appropriate similarity transmutations, and then solved using the bvp4c solver (MATLAB built-in function). The results of two scenarios, PEG−Water+ZrO2+MgO (hybrid nanofluid) and PEG−Water+ZrO2, (nanofluid) are reported. In order to draw important inferences about physical features, such as heat transfer rate, a correlation coefficient was used. The main findings of this study were that curvature parameter lowers fluid velocity, and Eckert number increases the temperature of fluid. It was observed that the volume fraction of nanoparticles enhances the skin friction coefficient and curvature parameter lessens the same. It was noticed that when curvature parameter (K) takes input in the range 0.5≤K≤2.5, the skin friction coefficient decreases at a rate of 1.46633 (i.e., 146.633%) (in the case of hybrid nanofluid) and 1.11236 (i.e., 111.236%) (in the case of nanofluid) per unit value of curvature parameter. Increasing rates in the skin friction parameter were 3.481179 (i.e., 348.1179%) (in the case of hybrid nanofluid) and 2.745679 (in the case of nanofluid) when the volume fraction of nanoparticle (ϕ1) takes input in the range 0≤ϕ1≤0.2. It was detected that, when Eckert number (Eck) increases, Nusselt number decreases. The decrement rates were observed as 1.41148 (i.e., 141.148%) (in the case of hybrid nanofluid) and 1.15337 (i.e., 153.337%) (in the case of nanofluid) when Eckert number takes input in the range 0≤Eck≤0.2. In case of hybrid nanofluid, it was discovered that the mass transfer rate increases at a rate of 1.497214 (i.e., 149.7214%) when chemical reaction (Kr) takes input in the range 0≤Kr≤0.2. In addition, we checked our findings against those of other researchers and discovered a respectable degree of agreement.