Free electrons moving through space are fundamental and indivisible: they are not built up of smaller particles, in contrast with protons and neutrons. However, within materials, interactions among electrons and atoms can give rise to quasiparticles, quantum states in which groups of electrons behave as new, particle-like excitations. Physicists have now successfully created quasiparticles that split the electron's orbital characteristics from its spin. To accomplish this, Justine Schlappa et al.
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- Frequent and reliable launch is here
- Battling Space Junk With a Tractor Beam of Static Electricity
- Introduction to Computer Information Systems/Storage
- Graphene to make large scale electricity storage a reality
- What is a hydrogen fuel cell?
- Working Papers: Electric Propulsion Technology Overview
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Frequent and reliable launch is hereVIDEO ON THE TOPIC: Windows Storage Spaces Demonstration
In many ways fuel cells are similar to batteries, such as those you might find in a car or in a portable electronic device like an MP3 player. However, there are some important differences between batteries and fuel cells. Similar to a battery, a fuel cell with a supply of hydrogen and oxygen can be used to power devices that use electricity. While both batteries and fuel cells convert chemical energy into electrical energy, batteries store this chemical energy inside the battery itself.
This means that a battery will run down, or need recharging, when there is no longer enough stored chemical energy available to produce sufficient electricity to power the device connected to the battery. Rather than storing chemical energy inside itself, a hydrogen fuel cell receives a supply of chemical energy from the outside. This chemical energy is stored in the hydrogen that is supplied to the anode of the fuel cell.
A hydrogen fuel cell essentially consumes hydrogen and oxygen. When a fuel cell is continuously supplied with hydrogen and oxygen, and the product water is removed, the fuel cell can generate electricity. Hydrogen fuel cells and batteries are both electrochemical cells. They each have two electrodes in contact with a material that can conduct ions, called an electrolyte.
One electrode is the anode and the other is the cathode. In a hydrogen fuel cell electrons are released from the hydrogen that is supplied to the anode whereas in a battery the electrons are released from the material in the anode itself. Because battery electrodes actively participate in the conversion of chemical energy to electrical energy, over time this can have a damaging effect on the electrodes and therefore on the effectiveness of the battery. Unlike batteries, the electrodes in hydrogen fuel cells are relatively stable since they act as catalysts in the release or acceptance of electrons and are not chemically changed during this process.
When pure hydrogen is used as the fuel, the only by-products generated from the fuel cell are pure water and heat. This makes fuel cells potentially very efficient devices with minimal environmental impact. Often both of these by-products can be put to some kind of use. For example, the heat can be used wherever a heat supply is needed.
Because hydrogen does not occur naturally in the environment, hydrogen fuel must be derived from other substances that contain hydrogen such asmethanol, gasoline, natural gas, and water.
Most hydrogen that is produced today comes from natural gas. If hydrogen is made from water the only byproduct is pure water. If fossil fuels are used as the original source of hydrogen there will be more by-products, such as carbon dioxide. When hydrogen is produced from water electricity is used to split the water molecule. If that electricity comes from a renewable energy source such as wind or solar power, then the resulting hydrogen is a renewable, zero emission fuel.
The oxygen is typically obtained from the air, though it can be provided directly as pure oxygen. Hydrogen gas is supplied to the anode of the fuel cell.
The anode is coated with platinum, which acts as a catalyst to break down the hydrogen into protons and electrons. If a circuit is connected between the anode and cathode then the electrons can travel through the circuit and provide power to any load that is connected as part of the circuit.
The flow of electrons through the load is the electric current that is generated by the fuel cell. The hydrogen ions protons that are produced from the hydrogen at the anode travel through the electrolyte in the fuel cell to the cathode. Oxygen supplied to the cathode reacts with these hydrogen ions and electrons arriving via the external circuit to produce water and heat, both of which are removed from the fuel cell.
In a PEM fuel cell bipolar plates are positioned at either side of the cell. They help to distribute gases and also serve as current collectors. The electrolyte is contained in a membrane between the anode and cathode, which are all sandwiched between the bipolar plates.
The membrane allows only protons to pass through and is called a proton exchange membrane, or PEM. In order to work properly the membrane must be kept moist. A typical hydrogen fuel cell produces 0. To increase the voltage individual cells can be connected in series. This arrangement is called a fuel cell stack. The cross sectional area of a fuel cellaffects its ability to produce current.
Greater area means more reaction sites, and this allows more current to be generated. Current times voltage equals power. Adobe Flash is required to access this simulation. If you are having trouble accessing it, please be sure you have installed the latest version of Flash on your computer. Still having trouble? Email us. Hydrogen is not a source of energy, while solar, wind, natural gas and oil are.
There are no naturally occurring sources or reservoirs of hydrogen on earth. Hydrogen can be extracted from fossil fuels, or can be produced by using the process of electrolysis to split water into hydrogen and oxygen. Both of these processes require energy. This energy can be provided by fossil fuels or by renewable sources of energy such as solar or wind. The hydrogen must be kept in a suitable container until it is ready to be used in a fuel cell to produce electricity.
In this sense, hydrogen is a way of storing and transporting energy, but not a source of energy itself. There are already many well-known types of devices that produce electricity, why should we consider another type? Every device has advantages and disadvantages that influence its suitability for use in a particular application or location. Hydrogen fuel cells have some unique characteristics that make them more suitable for certain uses than other sources of electricity.
The fuel cell itself is silent, although the equipment used to provide the hydrogen and oxygen may not be as quiet, depending on the type of equipment used. Being quiet makes fuel cells especially suitable when they are used in places that are close to people.
Also, fuel cells do not emit pollutants or toxins, so they can be used in enclosed areas without negatively affecting human health. They are also modular, meaning they can be stacked to generate various amounts of power as needed.
Fuel cells are also very efficient at converting chemical energy into electrical energy. Fuel cells can offer many potential benefits over batteries. Batteries can be recharged just as a canister of hydrogen can be refilled, but the capacity of batteries decreases over many recharge cycles. A container for hydrogen and a fuel cell, on the other hand, do not degrade over time. Additionally, a container for hydrogen can typically be refilled with hydrogen from an external source much faster than a battery can be fully recharged.
When batteries are used in an electric vehicle, the performance of the vehicle degrades as the battery discharges. In contrast, fuel cell performance remains the same as long as there is hydrogen fuel in the tank. Hydrogen is very combustible, just like gasoline. However, containers suitable for holding hydrogen are put through many rigorous tests to make sure they are safe for the public. Hydrogen is composed of very small, light molecules, and is much less dense than air. This means that a hydrogen leak will tend to disperse very rapidly upwards into the air, unlike a gasoline leak that will pool below a vehicle and remain a hazard until it evaporates.
The same precautions that people exercise at gas stations must also be used at hydrogen filling stations, such as not smoking and not using a cell phone.
The only by-products from combining hydrogen and oxygen in a fuel cell are water and heat, so hydrogen fuel cells do not emit greenhouse gases or other air pollutants as engines that use fossil fuels do. However, to produce hydrogen one must use another source of energy.
If fossil fuels are used as either the source of hydrogen or the source of energy for producing the hydrogen, then the net process does produce greenhouse gases. If water is used as the source of hydrogen and the process of making the hydrogen is powered by renewable sources of energy, such as solar or wind, then the use of hydrogen fuel cells is completely clean and sustainable and adds no greenhouse gases to the atmosphere.
Sir William Grove demonstrated the concept of the fuel cell in However, it was not until that Francis Bacon developed the first successful fuel cell. Limited progress was made over the next quarter century. The pace of development increased around the time that NASA began to research the technology for use in the Gemini, and later the Apollo, programs. Fuel cells are also used on the space shuttle fleet. Hydrogen fuel cells can be used to power any device that uses electricity.
So they can be used to power vehicles that run off electricity. How does the level of efficiency of a hydrogen fuel cell compare to other devices that produce electricity? Compare this to the energy transformations that occur when a heat engine such as a gas powered generator produces electricity:.
Since each energy transformation involves some amount of energy loss, the fuel cell is more efficient at producing electricity than a heat engine. Hydrogen fuel cells can be found in many different places today. Because the technology is still developing, most fuel cell applications to date have been for demonstration projects.
Applications have included small handheld devices, such as cell phones and laptop computers, electric vehicles, from passenger cars to buses, and stationary power for office buildings, hospitals, and other large commercial and institutional facilities.
They are also used in remote places where access to a conventional power supply is limited or impossible, such as off-grid home-sites and field weather stations. Currently fuel cells can be found from above the Earth in the space shuttles to below the ocean surface in some of the most recent submarines , and they are likely to be used more in the future.
Submit a Correction. Click on the links below to learn more about hydrogen fuel cells: What is a hydrogen fuel cell? A hydrogen fuel cell converts chemical energy stored by hydrogen fuel into electricity. How does a hydrogen fuel cell work? Frequently Asked Questions Is hydrogen a source of energy? Are hydrogen fuel cells safe for people and the environment? Are hydrogen fuel cells a new idea?
Battling Space Junk With a Tractor Beam of Static Electricity
Contact jom tms. Environmental concerns about using fossil fuels, and their resource constraints along with energy security concerns, have spurred great interest in generating electrical energy from renewable sources. The variable and stochastic nature of renewable sources, however, makes solar and wind power difficult to manage, especially at high levels of penetration. Electrical energy storage EES is necessary to effectively use intermittent renewable energy, enable its delivery, and improve the reliability, stability, and efficiency of the electrical grid. While EES has gained wide attention for hybrid and electrical vehicle needs, public awareness and understanding of the critical challenges in energy storage for renewable integration and the future grid is relatively lacking. This paper examines the benefits and challenges of EES, in particular electrochemical storage or battery technologies, and discusses the fundamental principles, economics, and feasibility of the storage technologies.
Introduction to Computer Information Systems/Storage
For small atoms, relativistic effects aren't very big. The binding energy of the electron in hydrogen is about That's about The rest energy of an electron is about , eV. So the kinetic energy is small compared to the rest energy, and thus relativistic effects are small. For the inner electrons in big atoms the energies are large enough for the relativistic effects to be major. The basic quantum rules the Dirac equation, for an electron apply whether or not the particle is in a bound state.
Source Citation: "Magnetism. Gale Research, Reproduced in Discovering Collection. Farmington Hills, Mich. December, Magnetism and electricity represent different aspects of the force of electromagnetism, which is one part of Nature's fundamental electroweak force. The region in space that is penetrated by the imaginary lines of magnetic force describes a magnetic field. The strength of the magnetic field is determined by the number of lines of force per unit area of space. Magnetic fields are created on a large scale either by the passage of an electric current through magnetic metals or by magnetized materials called magnets. The elemental metals-iron, cobalt, nickel, and their solid solutions or alloys with related metallic elements-are typical materials that respond strongly to magnetic fields.
Graphene to make large scale electricity storage a reality
As the demand for technology and technology itself continues to excel throughout history, so does user's wants and needs. The user's lifestyle pertaining to computers may revolve around publishing documents, creating presentations, media management, networking on the internet, and much more. In correlation with their wants and needs, there's the need to be able to have access to storage of the data being produced.
The growing problem of space junk around Earth could be cleaned up in part using the same forces that give you a static shock when you touch a doorknob on a windy day. By shooting space debris with an electron beam, a charged spacecraft could tug them to higher orbit and then fling them away. This solution relies on what are known as electrostatic forces, which occur whenever electrons build up on something. Bombarding a piece of space junk with electrons could give it a modest negative charge of a few tens of kilovolts, roughly the equivalent charge stored in a car spark plug. An unmanned space probe with a positive charge could then tow it in a tractor-beam-like fashion. Orbital debris is a well-known problem of the Space Age. In the early days of space travel, it was assumed that the area around Earth could absorb a near-limitless amount of junk. We figured that if we simply left our defunct satellites, spent rocket stages, and any pieces of garbage emerging from spacecraft for long enough, they would take care of themselves. The truth was rather different, and now we might be nearing a situation called the Kessler Syndrome where space debris is so prevalent that it increasingly collides with other orbital trash, fragmenting into thousands of new pieces of junk and rendering the orbits around Earth useless. The electrostatic force field method of cleaning up this problem would only work on some space junk, particularly that which sits at geostationary orbit about 36, kilometers above the surface. There are more than 1, large objects in geostationary orbit, and less than a third are functioning.
What is a hydrogen fuel cell?
In many ways fuel cells are similar to batteries, such as those you might find in a car or in a portable electronic device like an MP3 player. However, there are some important differences between batteries and fuel cells. Similar to a battery, a fuel cell with a supply of hydrogen and oxygen can be used to power devices that use electricity. While both batteries and fuel cells convert chemical energy into electrical energy, batteries store this chemical energy inside the battery itself. This means that a battery will run down, or need recharging, when there is no longer enough stored chemical energy available to produce sufficient electricity to power the device connected to the battery. Rather than storing chemical energy inside itself, a hydrogen fuel cell receives a supply of chemical energy from the outside. This chemical energy is stored in the hydrogen that is supplied to the anode of the fuel cell. A hydrogen fuel cell essentially consumes hydrogen and oxygen. When a fuel cell is continuously supplied with hydrogen and oxygen, and the product water is removed, the fuel cell can generate electricity. Hydrogen fuel cells and batteries are both electrochemical cells.
Working Papers: Electric Propulsion Technology Overview
Space Science Reviews. February , Cite as. The first major scientific discovery of the Space Age was that the Earth is enshrouded in toroids, or belts, of very high-energy magnetically trapped charged particles. Early observations of the radiation environment clearly indicated that the Van Allen belts could be delineated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. The energy distribution, spatial extent and particle species makeup of the Van Allen belts has been subsequently explored by several space missions. Recent observations by the NASA dual-spacecraft Van Allen Probes mission have revealed many novel properties of the radiation belts, especially for electrons at highly relativistic and ultra-relativistic kinetic energies. In this review we summarize the space weather impacts of the radiation belts.
The first use of spin-valve sensors in hard disk drive read heads was in the IBM Deskstar 16GP Titan, which was released in with IBM introduced the microdrive in , the smallest hard drive to date, with a capacity of MB on a single, 1-inch platter.
As chemistry advances go, few rival the impact of the lithium-ion battery. The light, compact batteries power much of the modern world, including our smartphones, laptops, and electric vehicles and, increasingly, the electricity system. Background: To make really energy-dense batteries that work well in portable products, you need a light and highly reactive material. Improved safety was the key to making the batteries a commercial product.
To view this site you can download a newer version of Internet Explorer. Introducing Electron, Rocket Lab's latest launch vehicle - delivering small satellites to low Earth orbit at an unprecedented frequency.
Manchester is the home of graphene, as the 'two-dimensional' one-atom-thick carbon allotrope was first isolated here in The University of Manchester is a powerhouse for applied and fundamental graphene research, with the National Graphene Institute leading the way. Graphene promises a revolution in electrical and chemical engineering. It is a potent conductor, extremely lightweight, chemically inert and flexible with a large surface area.