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Buses: ICE/Battery Hybrids
Vehicles that utilize more than one energy source for propulsion are usually termed hybrid vehicles. Although the onboard energy storage system (ESS) may be a flywheel or a hydraulic accumulator, most hybrid vehicles use chemical batteries or capacitors and are termed hybrid-electric vehicles. Fuel cells (FCs) may be used in hybrid-electric vehicles as primary power sources instead of conventional internal combustion engines (ICEs). In this article, ICE–battery hybrid transit buses are discussed specifically and contrasted with conventional drive buses. ...
8/29/2018 7:02:04 PM +00:00
Electric Vehicle: Batteries
History At the beginning of the automotive century, around 1900– 1910, battery electric vehicles (BEVs), cars with steam engines, and cars with gasoline engines coexisted. They were competing with respect to power, comfort, and maintenance. As described by R. H. Schallenberg, it took the electric starter and the starting, lighting, and ignition (SLI) system (created by Charles Kettering on the demand from Henry Leyland for the 1911 Cadillac Model Thirty) to improve the comfort in use of the gasoline engine vehicle sufficiently to outperform others. ...
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Light Traction: Fuel Cells
As a proton-exchange membrane fuel cell (PEMFC) can be started instantly at ambient temperatures and can work with air as oxidant without carbon dioxide problems, it is so far the most viable fuel cell (FC) system that has the potential to replace internal combustion engines (ICEs) and batteries for transportation applications to power cars, buses, and personal electric vehicles (PEVs). This article focuses on the application of this technology for light traction vehicles, such as scooters, bicycles, forklifts, wheelchairs, and tour carts. ...
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Hybrid Electric Vehicles: Batteries
The idea of combining electrical engines and internal combustion (IC) engines has a long history. In 1901 J. Lohner and F. Porsche had already presented a first hybrid electric vehicle (HEV). But this revolutionary concept did not reach full maturity because the electrical components were not developed. The main concern was the battery, a high-performing battery system with acceptable long-term endurance was not available at the time. The battery of the vehicle shown in Figure 1 had a weight of not less than 1800 kg. It was not until the end of the twentieth century that HEVs became a...
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Hybrid Electric Vehicles: Overview
Road traffic is one of the major consumers of energy, particularly in western industrialized countries, and globally it exhibits the highest growth rate in energy consumption of all sectors. In the Organisation for Economic Cooperation and Development (OECD) countries, more than 33% of the total final energy consumption goes into the transportation sector, amounting to more than 11% of the world’s total primary energy consumed. Virtually all of these vehicles are operated with internal combustion engines (ICEs) fueled with gasoline, diesel, or – to a very lower extent – different kinds of gases (compressed natural gas (CNG), liquefied petroleum...
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Hybrid Electric Vehicle: Plug-In Hybrids
There are different degrees of hybridization from microhybrids to extended-range electric vehicles (E-REVs). The complete range between nonhybridized vehicles and pure battery electric vehicles (EVs) is covered. Depending on the degree of hybridization, there are different functionalities available. Table 1 shows the functionality for full hybrid electric vehicles (full HEVs), plug-in hybrid electric-vehicles (PHEV Full HEV, full heavy electric vehicles; PHEVs) with 10 or 40 miles electric-only range, and E-REVs. ...
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Light Traction: Batteries
Electric two-wheelers (E2Ws) are a category of vehicles in China that includes two-wheel bikes propelled by human pedaling supplemented by electrical power from a storage battery (bicycle-style E2Ws or pedelecs), and low-speed scooters propelled almost solely by electricity (scooter-style E2Ws). Besides pedelecs, most E2Ws rely exclusively on electric power, not on human pedaling. In many countries, E2Ws are allowed to operate in the bicycle lane and are considered a bicycle from a regulatory perspective (i.e., helmets and driver’s licenses are not required). The technology of each type of E2W is similar. The main components of an E2W include a...
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Rail Vehicles: Fuel Cells
This article concerns the rationale, history, principal issues, and potential of fuel cell-powered rail vehicles. Issues include fuel cell type, hydrogen storage, special factors affecting fuel cell rail, and the question of which rail applications are appropriate for hybrid powertrains. It concludes with a brief discussion of a supersonic concept vehicle, a cross between a train and an airplane that operates in a hydrogen-filled tube and levitates on a gas film, thereby overcoming an inherent efficiency limitation of aircraft. ...
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Satellites: Batteries
The successful accomplishment of a space mission is dependent on proper and reliable functioning of the power system of the spacecraft in orbit. The stringent demands on performance including weight, volume, reliability, durability, and cost make the design of the spacecraft power system a challenging exercise. Further, since a space mission is inherently expensive, the necessity of optimization and built-in reliability becomes a rule rather than an exception for all the onboard systems. Therefore, continuous efforts are being made to realize better performance of power systems and new technologies are brought to use continually. The different elements of the...
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Ships: Fuel Cells
The recent fuel cell (FC) development worldwide has always been accompanied by a number of studies and projects investigating the applications of FCs onboard ships. Almost all possible FC types and different fuels such as hydrogen, natural gas (liquefied or pressurized), liquefied pressurized gas (LPG), methanol, and maritime diesel have been considered. These applications of FCs are still mainly focused on onboard power generation (OPU) and propulsion. The types of ships being considered vary from sailing and other leisure boats to ferries, naval surface ships, submarines, and special underwater vehicles such as those used for research or military applications....
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Solar Cars: Batteries
On 19 December 1982, the Australian adventurer Hans Tholstrup manoeuvred the idea of a solar-powered land vehicle from concept to reality. With the assistance of fellow Australian Larry Perkins, an engineer and an accomplished race driver, Tholstrup set out from Perth on the west coast of Australia in the fragile Quiet Achiever (Figure 1(a)) – now widely acknowledged to be the world’s first solar car. An immediate target was to beat the 28 days set by Francis Birtles in 1912 in the first motor vehicle to cross the Continent (Figure 1(b)). ...
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Submersibles: Batteries
Submersibles are a large and nonhomogeneous group of vehicles that range from small unmanned autonomous vehicles such as Gavia and REMUS that can be carried by one or two men, to medium-large unmanned submersibles such as torpedoes, survey vehicles such as HUGIN and Bluefin, larger manned deep-diving vehicles such as the US Alvin and the Russian MIR up to naval diesel-electric submarines. With a few exceptions, all these use electrochemical power sources for propulsion. The rate of discharge is very different, however, being C/50 or less for a survey type of an autonomous underwater vehicle (AUV) to 5C or...
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Portable Devices: Fuel Cells
The rapid growth of the portable electronics market includes ‘power-hungry’ accessories in a smaller system, which has led to the search for an alternative and advanced power source due to the limited energy density of conventional lithium-ion batteries. Table 1 lists the power demand of the different portable applications. Fuel cells promise to provide a more reliable and longer operational time than batteries. As the energy is stored as a reservoir rather than as an integral part of the power source, fuel cells have advantages over batteries. Micro fuel cell products compete with power systems that utilize both direct...
8/29/2018 7:02:01 PM +00:00
Military: Batteries and Fuel Cells
In order to ensure their own leadership capability, sustainability, supportability, mobility, or survivability, modern armed forces are becoming increasingly dependent upon having a reliable supply of electrical energy. Consequently, electrochemical power sources are becoming increasingly important as a means to guarantee this reliable power supply. As this concerns quite a broad field of applications, the potential solutions using electrochemical power sources are also quite different. This article focuses on one specific sector, that of portable applications. ...
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Notebooks: Batteries
Notebook computers are complex devices. Figure 1 depicts the basic elements that comprise a notebook computer and shows how they fit together. It includes the operating environment and user, as well as the computer, battery pack, and the fundamental electrochemical cell that drives its operation. Since notebooks are portable, it is essential to have a lightweight, sealed battery to prevent leakage of electrolyte into the computer case. Two types of batteries are found in a notebook computer. One is a rechargeable battery pack that provides the energy for its operation. The pack is usually composed of several lithium-ion cells...
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Portable Devices: Batteries
Portable devices powered by batteries have experienced a dramatic growth in the last several years. In particular, devices such as cellular phones, portable computers, cameras, camcorders, and cordless tools have given a remarkable impulse to the market. The advancements in the field of transistors and other electronic components have been impressive and have played a very important role in this development. The so-called Moore’s law states, in its widely accepted form, that ‘the number of transistors in integrated circuits doubles every 18 months’. ...
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Fuel Cells
This article covers post-prototype fuel cell (FC) systems in stationary or ‘on-site’ applications, for use in non-grid-connected dispersed generation, or grid-connected distributed generation. Both are referred to here as DG. They include a range of sizes from kilowatt to megawatt scale, and may be in combined heat and power (CHP, cogeneration or dual energy use systems), or as electricity-only units. Trigeneration (combined heat, power, and cooling) is a further possibility. The article starts with a general discussion of on-site power systems, and introduces the different types of FC devices for these applications. This is followed by general sections on...
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Power Tools: Batteries
The name ‘power tool’ originally describes a tool that is powered by an electrical motor. Thus, the effort needed by an operator is reduced through using this tool. Today the term ‘power tool’ or ‘cordless tool’, as it is also called sometimes, is most commonly used for an electric tool, which is powered by batteries. This makes the user independent of power outlets. Power tools include drills and screwdrivers as well as hammers, saws, grinders, etc. They replace their electric power grid– connected equivalents. The first electrified drill was patented by Arthur James Arnot (1865–1946) on 20 August 1889,...
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Cogeneration of Energy and Chemicals: Fuel Cells
Fuel cells (FCs) are electrochemical systems that continuously produce electric energy and heat, where the reactants (fuel and oxidant) are fed to the electrodes and the reaction products are removed from the cell. The chemical energy of the reactants is directly converted into electricity, reaction products, and heat without involving combustion processes. The efficiencies of the FCs are about twice those of the heat engines because the latter are affected by the limitations imposed by Carnot’s theorem. Electricity is normally the main product of FCs, the chemicals and heat generated being the waste products of the first (or primary) cycle....
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APPLICATIONS – STATIONARY
Vast quantities of energy are the engine that powers the well-being and comfort of humanity on this planet, and it is difficult to imagine what our existence would be like in lieu of that abundance. Maintenance of the existing, reasonable balance between the need for energy and the available resources endures because of the continuing discovery of new energy resources and our ability to continually improve the efficiency of that energy’s use.
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Fuel Cell/Gas Turbine Hybrid
With increasing energy demands, dwindling fossil energy resources, and environmental concerns associated with criteria pollutants and greenhouse gases, significant attention in the power generation community has been focused on increasing efficiency and reducing emissions. A highly efficient and low-emission concept is the fuel cell gas turbine (GT) hybrid. Hybrid systems are comprised of fuel cells integrated with a GT engine. A variety of potential configurations have been proposed and a number of cycles have been investigated. The advantage sought is a synergism that yields a performance that exceeds the simple sum of the two systems. Both experimental and theoretical...
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Aviation: Battery
Batteries are an essential component of virtually all aircraft electrical systems. Aircraft batteries are used to start engines and auxiliary power units (APUs), provide emergency backup power for essential avionics equipment and lighting systems, assure no-break power for navigation units and fly-by-wire computers, and to provide ground power capability for maintenance and preflight checkouts. Many of these functions are critical to the safe operation of the aircraft, so the reliability of an aircraft battery is of utmost importance. Other important characteristics include power and energy density, environmental durability, operating temperature range, ease of maintenance, rapid recharge capability, shelf life,...
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Residential Energy Supply: Fuel Cells
For most of the time, electric energy supply was based on large centralized power stations, the biggest of them located close to coal mines. Electricity distribution traditionally is done by means of high voltage power lines feeding the electricity distribution grid. With time, electric utilities became large enterprises integrating electricity generation, distribution, and customer relations. Electricity generation mainly is powered by heat engines, their efficiency being determined by the temperature difference of the work fluid. Due to their location, most central power stations could not make use of the low-temperature waste heat resulting as a by-product of electricity generation....
8/29/2018 7:02:01 PM +00:00
Uninterruptible and Back-up Power: Fuel Cells
Backup Power Systems for Mobile Telecommunications Telecommunication networks are a major user of backup powering systems (also termed uninterruptible power systems (UPS)) and they serve as the primary example of a fuel cell (FC) application in this article. Mobile or wireless networks are often the primary source of telecommunications especially in emerging markets and developing countries where fixed line networks have not been extensively built. Customers expect to continue to use their mobile phones, even when the power grid fails. In extreme cases, need to be reached and need to continue with their communication. The mobile network is based...
8/29/2018 7:02:01 PM +00:00
APPLICATIONS – TRANSPORTATION
The need for electric power onboard automobiles is rapidly growing owing to an increased number of electrical components, improving safety, economy, and comfort. The most important feature in this regard is the air conditioning in the stationary phase. This feature is presently realized mostly by idling the main engine.
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Chương 4: Trao đổi nhiệt bằng Bức xạ
4.1 Khái niệm chung về Bức xạ nhiệt 4.2 Các định luật cơ bản về Bức xạ nhiệt 4.3 Trao đổi nhiệt Bức xạ giữa các vật rắn đặt trong môi trường trong suốt Hai tấm phẳng đặt song song Hai vật bọc nhau Tác dụng của màn chắn p.1 Người soạn: TS. Hà anh Tùng ĐHBK tp HCM 8/2009 4.1 Khái niệm chung về BỨC XẠ NHIỆT ĐN: là quá trình trao đổi nhiệt xảy ra giữa các vật có nhiệt độ khác nhau đặt cách xa nhau Năng lượng bức xạ truyền trong không gian dưới dạng sóng điện từ p.2 Người soạn: TS. Hà...
8/29/2018 7:01:54 PM +00:00
Chương 3: Trao đổi nhiệt bằng đối lưu
Khái niệm chung về TĐN Đối lưu 3.2 Một số yếu tố cơ bản ảnh hưởng TĐN Đối lưu 3.3 Các pt vi phân TĐN Đối lưu 3.4 Cơ sở lý luận đồng dạng 3.5 Các tiêu chuẩn đồng dạng của TĐN Đối lưu ổn định
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Chương 4: Trao đổi nhiệt đối lưu trong môi trường 1 pha
Tỏa nhiệt đối lưu tự nhiên 4.3 Tỏa nhiệt đối lưu cưỡng bức NHẮC LẠI: Để tính trao đổi nhiệt đối lưu Q F Tw trong đó: thường dùng công thức Newton: Q = α F (Tw − T f ) (W) (W/m2) Tf hay ΔT q= 1/ α - α là hệ số tỏa nhiệt đối lưu (W/m2.K) - F là diện tích bề mặt trao đổi nhiệt (m2) THỰC NGHIỆM - Tw là nhiệt độ trung bình của bề mặt ( K hoặc oC) - Tf là nhiệt độ trung bình của chất lỏng ( K hoặc oC) p.2 Người soạn: TS. Hà anh Tùng ĐHBK tp HCM 8/2009 Hệ số tỏa...
8/29/2018 7:01:54 PM +00:00
MATLAB ỨNG DỤNG CHO NGÀNH HÓA HỌC VÀ CÔNG NGHỆ HÓA HỌC
Để có thông tin mới nhất về yêu cầu của hệ thống chúng ta có thể vào MathWorks Web site (www.mathworks.com), system requirements page. Matlab là một phần mềm có yêu cầu khá cao với hệ thống máy tính, để chạy phần mềm này máy tính cần đảm bảo những yếu tố tối thiểu sau: Bộ xử lý: Pentium, Pentium Pro, Pentium II, Pentium III, Pentium IV, or AMD Athlon Hệ điều hành: Microsoft Windows 95, Windows 98 (original and Second Edition), Windows NT 4.0 (with Service Pack 5 for Y2K compliancy) or Windows 2000 Ổ CD-ROM để cài đặt....
8/29/2018 7:01:44 PM +00:00
Quy trình sản xuất trà túi lọc - ks.phan quang thoai
Tea has existed as a beverage since 2000 B.C. The brewing, serving, and drinking of tea are time-honored rituals throughout the world. While there is general agreement that the tea trade began in China, both China and India lay claim to discovering the dietary properties of tea leaves. The Chinese tell the story of a mythical emperor named Shen Nung who was so particular about his nutrition that he boiled his drinking water before he drank it. One day, the story goes, the wind caught some of the leaves on the tree branches that he had used to build a fire. The leaves floated into his boiling...
8/29/2018 6:58:25 PM +00:00