The Experts below are selected from a list of 1410 Experts worldwide ranked by ideXlab platform
Christoph Von Ballmoos - One of the best experts on this subject based on the ideXlab platform.
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Alternative proton binding mode in ATP synthases
Journal of Bioenergetics and Biomembranes, 2007Co-Authors: Christoph Von BallmoosAbstract:ATP synthases are Rotary Engines which use the energy stored in a transmembrane electrochemical gradient of protons or sodium ions to catalyze the formation of ATP by ADP and inorganic phosphate. Current models predict that protonation/deprotonation of specific amino acids of the rotating c-ring, extracting protons from one side and delivering them to the other side of the membrane, are at the core of the proton translocation mechanism of these enzymes. In this minireview, an alternative proton binding mechanism is presented, considering hydronium ion coordination as proposed earlier. Biochemical data and structural considerations provide evidence for two different proton binding modes in the c-ring of H^+-translocating ATP synthases. Recent investigations in several other proton translocating membrane proteins suggest, that hydronium ion coordination by proteins might display a general principle which was so far underestimated in ATP synthases.
Drbal Milan - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic model of Wankel engine with output power 11 kW
Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017Co-Authors: Drbal MilanAbstract:The master’s thesis deals with the Wankel Rotary Engines and their 1D simulations using a thermodynamic simulation software for the piston Engines. The necessary steps for creation of the equivalent model of the four-stroke three-cylinder combustion engine are provided. The engine used for the validation model was Aixro XR 50. The data measured on this engine during testing were used to validate the created thermodynamic model. The discharge coefficient calculation of the intake and the exhaust ports is shown. The 11kW engine design is created using validated thermodynamic model
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Thermodynamic model of Wankel engine with output power 11 kW
Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017Co-Authors: Drbal MilanAbstract:Práce se zabývá rozborem problematiky rotačních motorů typu Wankel a jejich modelování v 1D simulačních programech určených pro termodynamické simulace pístových motorů. Jsou popsány nutné kroky k vytvoření ekvivalentního modelu čtyřdobého tříválcového pístového motoru, pomocí kterého jsou poté získávány výsledky výpočtů. Jako validační motor je použit Aixro XR 50. Data naměřená na tomto motoru jsou poté použita k validaci vytvořeného termodynamického modelu. Dále je uvedeno určování průtokových koeficientů jednotlivých částí sání a výfuku motoru. Na základě vytvořeného termodynamického modelu je proveden návrh motoru s výkonem 11kW.The master’s thesis deals with the Wankel Rotary Engines and their 1D simulations using a thermodynamic simulation software for the piston Engines. The necessary steps for creation of the equivalent model of the four-stroke three-cylinder combustion engine are provided. The engine used for the validation model was Aixro XR 50. The data measured on this engine during testing were used to validate the created thermodynamic model. The discharge coefficient calculation of the intake and the exhaust ports is shown. The 11kW engine design is created using validated thermodynamic model.
A H De Boer - One of the best experts on this subject based on the ideXlab platform.
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14 3 3 protein is a regulator of the mitochondrial and chloroplast atp synthase
Proceedings of the National Academy of Sciences of the United States of America, 2001Co-Authors: Tom D Bunney, H S Van Walraven, A H De BoerAbstract:Mitochondrial and chloroplast ATP synthases are key enzymes in plant metabolism, providing cells with ATP, the universal energy currency. ATP synthases use a transmembrane electrochemical proton gradient to drive synthesis of ATP. The enzyme complexes function as miniature Rotary Engines, ensuring energy coupling with very high efficiency. Although our understanding of the structure and functioning of the synthase has made enormous progress in recent years, our understanding of regulatory mechanisms is still rather preliminary. Here we report a role for 14-3-3 proteins in the regulation of ATP synthases. These 14-3-3 proteins are highly conserved phosphoserine/phosphothreonine-binding proteins that regulate a wide range of enzymes in plants, animals, and yeast. Recently, the presence of 14-3-3 proteins in chloroplasts was illustrated, and we show here that plant mitochondria harbor 14-3-3s within the inner mitochondrial-membrane compartment. There, the 14-3-3 proteins were found to be associated with the ATP synthases, in a phosphorylation-dependent manner, through direct interaction with the F1 β-subunit. The activity of the ATP synthases in both organelles is drastically reduced by recombinant 14-3-3. The rapid reduction in chloroplast ATPase activity during dark adaptation was prevented by a phosphopeptide containing the 14-3-3 interaction motif, demonstrating a role for endogenous 14-3-3 in the down-regulation of the CFoF1 activity. We conclude that regulation of the ATP synthases by 14-3-3 represents a mechanism for plant adaptation to environmental changes such as light/dark transitions, anoxia in roots, and fluctuations in nutrient supply.
David C. Walther - One of the best experts on this subject based on the ideXlab platform.
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development and characterisation of small scale Rotary Engines
International Journal of Alternative Propulsion, 2007Co-Authors: Bennett S Sprague, David C. Walther, Albert P. Pisano, Sang Won Park, Carlos Fernandez A PelloAbstract:This paper describes the development and characterisation of small-scale Rotary Engines with displacements in the range of 781500 mm for portable applications in the range of 10200 W of power output. Small-scale combustion Engines present a number of research challenges including manufacturing tolerances, sealing, thermal management, ignition, combustion efficiency and porting. Four Engines have been characterised using a custom test bench and show an increase in performance due to design changes that mitigate the challenges associated with small-scale Engines. The volumetric power density has been increased from 11 W/cm in a 348 mm engine operating with a supercharged hydrogen/air mixture to 22 W/cm in a 1500 mm engine operating with naturally aspirated liquid hydrocarbon fuel. The thermal efficiency has also been increased from 0.2 to 4%. Continued improvements in sealing, thermal management, combustion efficiency and friction reduction will allow further increases in engine performance.
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development of liquid fuel injection system for small scale Rotary Engines
44th AIAA Aerospace Sciences Meeting and Exhibit, 2006Co-Authors: Sang Won Park, David C. Walther, Albert P. Pisano, Berkeley Sensor, Carlos A FernandezpelloAbstract:*† ‡ § In an attempt to optimize the performance of small scale internal combustion Rotary Engines for portable power generation, an investigation and development effort for a liquid fuel delivery system is ongoing. Engine operation sets a pair of primary design constraints for liquid fuel delivery systems: fuel mass flow rate and maximum droplet diameter. The fuel mass flow rate requirement is dictated by the stoichiometry, the engine geometry, and the engine residence time as determined by engine (rotational) speed. The droplet diameter constraint is generated from the engine geometry and the residence time. Similarly, the field of use limits operational parameters, such as delivery pressure, subsystem power requirements, and overall system weight. A theoretical prediction has been carried out to determine the required fuel flow rate and initial droplet size for a small-scale Rotary engine. For an engine operation of having residence time of 9ms (rotational speed: 10,000RPM), 40mg/sec of methanol with 60µm of initial droplet diameter is required. Guided by these fuel delivery requirements, experimental measurements have been performed using commercially available micro dispensing valves to determine their viability. It was determined that these valves are capable of delivering 10-100mg/sec of fuel with a droplet diameter range of 210-360µm for pressures expected in portable power devices, and commercially available orifice diameters. Several injector parameters, such as the size of orifice, the driving pressure, and the duty cycle, have been varied to determine the effect on mass flow rate and size of droplets to guide future designs. Due to large discrepancy between required initial size of droplets and measurements, the concept of evaporating fuel by external heat source has been adapted and implemented. Using an evaporator, a fuel injector was successfully delivered fuel up to 50mg/sec as mostly vaporized droplets. The results of this study will be applied to develop a fuel delivery system for standalone portable power applications such as micro-scale Engines, turbines and potentially fuel cells.
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Design and experimental results of small-scale Rotary Engines
2001 ASME International Mechanical Engineering Congress and Exposition November 11 2001 - November 16, 2001Co-Authors: Kelvin Fu, Kenji Miyaska, David C. Walther, Dorian Liepmann, Carlos Fernandez-pello, Fabian C. Martinez, Aaron J. Knobloch, Albert P. Pisano, Kazuteru MarutaAbstract:A research project is currently underway to develop small-scale internal combustion Engines fueled by liquid hydrocarbons. The ultimate goal of the MEMS Rotary Internal Combustion Engine Project is to develop a liquid hydrocarbon fueled MEMS-size Rotary internal combustion micro-engine capable of delivering power on the order of milli-watts. This research is part of a larger effort to develop a portable, autonomous power generation system with an order of magnitude improvement in energy density over alkaline or lithium-ion batteries. The Rotary (Wankel-type) engine is well suited for the fabrication techniques developed in the integrated chip (IC) community and refined by the MicroElectroMechanical Systems (MEMS) field. Features of the Rotary engine that lend itself to MEMS fabrication are its planar construction, high specific power, and self-valving operation. The project aims at developing a "micro-Rotary" engine with an epitrochoidal-shaped housing under 1 mm3 in size and with a rotor swept volume of 0.08 mm3. To investigate engine behavior and design issues, larger-scale "mini-Rotary" Engines have been fabricated from steel. Mini-Rotary engine chambers are approximately 1000 mm3 to 1700 mm3 in size and their displacements range from 78 mm3 to 348 mm 3. A test bench for the mini-Rotary engine has been developed and experiments have been conducted with gaseous-fueled mini-Rotary Engines to examine the effects of sealing, ignition, design, and thermal management on efficiency. Preliminary testing has shown net power output of up to 2.7 W at 9300 RPM. Testing has been performed using hydrogen-air mixtures and a range of spark and glow plug designs as the ignition source. Iterative design and testing of the mini-engine has lead to improved sealing designs. These particular designs are such that they can be incorporated into the fabrication of the micro-engine. Design and fabrication of a first generation meso-scale Rotary engine has been completed using a SiC molding process developed at Case Western Reserve University. The fabrication of the micro-Rotary engine is being conducted in U.C. Berkeley's Microfabrication Laboratory. Testing of the mini-engine has lead to the conclusion that there are no fundamental phenomena that would prevent the operation of the micro-engine. However, heat loss and sealing issues are key for efficient operation of the micro-engine, and they must be taken into account in the design and fabrication of the micro-Rotary engine. The mini-Rotary engine design, testing, results and applications will be discussed in this paper.
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Design and experimental results of small-scale Rotary Engines
2001Co-Authors: Aaron J. Knobloch, Kenji Miyaska, David C. Walther, Dorian Liepmann, Carlos Fernandez-pello, Fabian C. Martinez, P. Pisano, Kaoru MarutaAbstract:A research project is currently underway to develop small-scale internal combustion Engines fueled by liquid hydrocarbons. The ultimate goal of the MEMS Rotary Internal Combustion Engine Project is to develop a liquid hydrocarbon fueled MEMS-size Rotary internal combustion micro-engine capable of delivering power on the order of milli-watts. This research is part of a larger effort to develop a portable, autonomous power generation system with an order of magnitude improvement in energy density over alkaline or lithium-ion batteries. The Rotary (Wankel-type) engine is well suited for the fabrication techniques developed in the integrated chip (IC) community and refined by the MicroElectroMechanical Systems (MEMS) field. Features of the Rotary engine that lend itself to MEMS fabrication are its planar construction, high specific power, and self-valving operation. The project aims at developing a "micro-Rotary" engine with an 3 epitrochoidal-shaped housing under 1 mm in size and with a rotor swept volume of 0.08 mm 3. To investigate engine behavior and design issues, larger-scale "mini-Rotary" Engines have been fabricated from steel. Mini-Rotary engine chambers are approximately 1000 mm 3 to 1700 mm 3 in size and their displacements range from 78 mm 3 to 348 mm 3. A test bench for the mini-Rotary engine has been developed and experiments have been conducted with gaseous-fueled mini-Rotary Engines to examine the effects of sealing, ignition, design, and thermal management on efficiency. Preliminary testing has shown net power output of up to 2.7 W at 9300 RPM. Testing has been performed using hydrogen-air mixtures and a range of spark and glow plug designs as the ignition source. Iterative design and testing of the miniengine has lead to improved sealing designs. These particular designs are such that they can be incorporated into the fabrication of the micro-engine. Design and fabrication of a first generation meso-scale Rotary engine has been completed using a SiC molding process developed at Case Western Reserve University. The fabrication of the micro-Rotary engine is being conducted in U.C. Berkeley's Microfabrication Laboratory. Testing of the mini-engine has lead to the conclusion that there are no fundamental phenomena that would prevent the operation of the micro-engine. However, heat loss and sealing issues are key for efficient operation of the micro-engine, and they must be taken into account in the design and fabrication of the micro-Rotary engine. The mini-Rotary engine design, testing, results and applications will be discussed in this paper. NOMENCLATURE
Ali Emadi - One of the best experts on this subject based on the ideXlab platform.
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modern electric hybrid electric and fuel cell vehicles fundamentals theory and design
2004Co-Authors: Morteza Ehsani, Ali EmadiAbstract:Environmental Impact and History of Modern Transportation Air Pollution Global Warming Petroleum Resources Induced Costs Importance of Different Transportation Development Strategies to Future Oil Supply History of EVs History of HEVs History of Fuel Cell Vehicles Fundamentals of Vehicle Propulsion and Brake General Description of Vehicle Movement Vehicle Resistance Dynamic Equation Tire-Ground Adhesion and Maximum Tractive Effort Power Train Tractive Effort and Vehicle Speed Vehicle Power Plant and Transmission Characteristics Vehicle Performance Operating Fuel Economy Brake Performance Internal Combustion Engines 4S, Spark-Ignited IC Engines 4S, Compression-Ignition IC Engines 2S Engines Wankel Rotary Engines Stirling Engines Gas Turbine Engines Quasi-Isothermal Brayton Cycle Engines Electric Vehicles Configurations of EVs Performance of EVs Tractive Effort in Normal Driving Energy Consumption Hybrid Electric Vehicles Concept of Hybrid Electric Drive Trains Architectures of Hybrid Electric Drive Trains Electric Propulsion Systems DC Motor Drives Induction Motor Drives Permanent Magnetic BLDC Motor Drives SRM Drives Design Principle of Series (Electrical Coupling) Hybrid Electric Drive Train Operation Patterns Control Strategies Design Principles of a Series (Electrical Coupling) Hybrid Drive Train Design Example Parallel (Mechanically Coupled) Hybrid Electric Drive Train Design Drive Train Configuration and Design Objectives Control Strategies Parametric Design of a Drive Train Simulations Design and Control Methodology of Series-Parallel (Torque and Speed Coupling) Hybrid Drive Train Drive Train Configuration Drive Train Control Methodology Drive Train Parameters Design Simulation of an Example Vehicle Design and Control Principles of Plug-In Hybrid Electric Vehicles Statistics of Daily Driving Distance Energy Management Strategy Energy Storage Design Mild Hybrid Electric Drive Train Design Energy Consumed in Braking and Transmission Parallel Mild Hybrid Electric Drive Train Series-Parallel Mild Hybrid Electric Drive Train Peaking Power Sources and Energy Storages Electrochemical Batteries Ultracapacitors Ultra-High-Speed Flywheels Hybridization of Energy Storages Fundamentals of Regenerative Breaking Braking Energy Consumed in Urban Driving Braking Energy versus Vehicle Speed Braking Energy versus Braking Power Braking Power versus Vehicle Speed Braking Energy versus Vehicle Deceleration Rate Braking Energy on Front and Rear Axles Brake System of EV, HEV, and FCV Fuel Cells Operating Principles of Fuel Cells Electrode Potential and Current-Voltage Curve Fuel and Oxidant Consumption Fuel Cell System Characteristics Fuel Cell Technologies Fuel Supply Non-Hydrogen Fuel Cells Fuel Cell Hybrid Electric Drive Train Design Configuration Control Strategy Parametric Design Design Example Design of Series Hybrid Drive Train for Off-Road Vehicles Motion Resistance Tracked Series Hybrid Vehicle Drive Train Architecture Parametric Design of the Drive Train Engine/Generator Power Design Power and Energy Design of Energy Storage Appendices Index
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modern electric hybrid electric and fuel cell vehicles fundamentals theory and design
2004Co-Authors: Morteza Ehsani, Yimi Gao, Ali EmadiAbstract:Environmental Impact and History of Modern Transportation Air Pollution Global Warming Petroleum Resources Induced Costs Importance of Different Transportation Development Strategies to Future Oil Supply History of EVs History of HEVs History of Fuel Cell Vehicles Fundamentals of Vehicle Propulsion and Brake General Description of Vehicle Movement Vehicle Resistance Dynamic Equation Tire-Ground Adhesion and Maximum Tractive Effort Power Train Tractive Effort and Vehicle Speed Vehicle Power Plant and Transmission Characteristics Vehicle Performance Operating Fuel Economy Brake Performance Internal Combustion Engines 4S, Spark-Ignited IC Engines 4S, Compression-Ignition IC Engines 2S Engines Wankel Rotary Engines Stirling Engines Gas Turbine Engines Quasi-Isothermal Brayton Cycle Engines Electric Vehicles Configurations of EVs Performance of EVs Tractive Effort in Normal Driving Energy Consumption Hybrid Electric Vehicles Concept of Hybrid Electric Drive Trains Architectures of Hybrid Electric Drive Trains Electric Propulsion Systems DC Motor Drives Induction Motor Drives Permanent Magnetic BLDC Motor Drives SRM Drives Design Principle of Series (Electrical Coupling) Hybrid Electric Drive Train Operation Patterns Control Strategies Design Principles of a Series (Electrical Coupling) Hybrid Drive Train Design Example Parallel (Mechanically Coupled) Hybrid Electric Drive Train Design Drive Train Configuration and Design Objectives Control Strategies Parametric Design of a Drive Train Simulations Design and Control Methodology of Series-Parallel (Torque and Speed Coupling) Hybrid Drive Train Drive Train Configuration Drive Train Control Methodology Drive Train Parameters Design Simulation of an Example Vehicle Design and Control Principles of Plug-In Hybrid Electric Vehicles Statistics of Daily Driving Distance Energy Management Strategy Energy Storage Design Mild Hybrid Electric Drive Train Design Energy Consumed in Braking and Transmission Parallel Mild Hybrid Electric Drive Train Series-Parallel Mild Hybrid Electric Drive Train Peaking Power Sources and Energy Storages Electrochemical Batteries Ultracapacitors Ultra-High-Speed Flywheels Hybridization of Energy Storages Fundamentals of Regenerative Breaking Braking Energy Consumed in Urban Driving Braking Energy versus Vehicle Speed Braking Energy versus Braking Power Braking Power versus Vehicle Speed Braking Energy versus Vehicle Deceleration Rate Braking Energy on Front and Rear Axles Brake System of EV, HEV, and FCV Fuel Cells Operating Principles of Fuel Cells Electrode Potential and Current-Voltage Curve Fuel and Oxidant Consumption Fuel Cell System Characteristics Fuel Cell Technologies Fuel Supply Non-Hydrogen Fuel Cells Fuel Cell Hybrid Electric Drive Train Design Configuration Control Strategy Parametric Design Design Example Design of Series Hybrid Drive Train for Off-Road Vehicles Motion Resistance Tracked Series Hybrid Vehicle Drive Train Architecture Parametric Design of the Drive Train Engine/Generator Power Design Power and Energy Design of Energy Storage Appendices Index
