Oxide Ceramics – Piezo-ceramics Piezo-ceramic materials are categorized as functional ceramics. In sensors they make it possible to convert forces, pressures and accelerations into electrical signals, and in sonic and ultrasonic transducers and actuators they convert electric voltages into vibrations or deformations. Piezo-ceramic materials are classified according to their chemical composition on the one hand, and by the specific application conditions on the other. CeramTec distinguishes between the following material categories: Materials for power transducers (ultrasonic applications) Materials for sensors (ultrasonic transmitters and receivers) Materials for actuators (precision positioning or injection systems) Materials for special applications Contacting of the metalized piezo-ceramics can be made using conductive adhesives, conductive rubbers, spring contacts or via soldering.
Magnetostriction Animation of magnetostriction Magnetostriction (cf. electrostriction) is a property of ferromagnetic materials that causes them to change their shape or dimensions during the process of magnetization. The variation of materials's magnetization due to the applied magnetic field changes the magnetostrictive strain until reaching its saturation value, λ. This effect causes losses due to frictional heating in susceptible ferromagnetic cores. Explanation[edit] Internally, ferromagnetic materials have a structure that is divided into domains, each of which is a region of uniform magnetic polarization. The reciprocal effect, the change of the susceptibility (response to an applied field) of a material when subjected to a mechanical stress, is called the Villari effect. The Villari reversal is the change in sign of the magnetostriction of iron from positive to negative when exposed to magnetic fields of approximately 40,000 A/m (500 oersteds). Magnetostrictive materials[edit] See also[edit]
Summary: Neighbourhood or community group purchase and distribution of energy saving equipment | Community Pathways Installation or use of energy saving equipment reduces household's energy bills as well as reducing their carbon emissions. Providing community members directly with the physical means to improve the energy efficiency of their homes overcomes barriers of inertia and feelings of hassle, which enables them to take action. At the same time, working together on a shared agenda strengthens social norms, which can reinforce the low carbon activities being undertaken, and increase the potential for future actions. Purchasing in bulk may also be a way to get discounts, or at least an efficient way to seek 'best buys' on behalf of the community. It may also be more effective as a group to seek funding than as separate individuals, for example from energy suppliers or other commercial bodies with new products to promote or environmental or social objectives and targets to meet.
Electromagnetic field The field can be viewed as the combination of an electric field and a magnetic field. The electric field is produced by stationary charges, and the magnetic field by moving charges (currents); these two are often described as the sources of the field. The way in which charges and currents interact with the electromagnetic field is described by Maxwell's equations and the Lorentz force law. From a classical perspective in the history of electromagnetism, the electromagnetic field can be regarded as a smooth, continuous field, propagated in a wavelike manner; whereas from the perspective of quantum field theory, the field is seen as quantized, being composed of individual particles. Structure of the electromagnetic field[edit] The electromagnetic field may be viewed in two distinct ways: a continuous structure or a discrete structure. Continuous structure[edit] Classically, electric and magnetic fields are thought of as being produced by smooth motions of charged objects. (Gauss's law) where
Energy Purchase & Sales — Community Renewable Energy A community renewable developer can recoup some, if not all, of its costs by entering into agreements with utilities to purchase the output of the project. In addition to energy, a utility may place value on, and hence be willing to pay for, capacity, identified distribution or transmission benefits, and environmental benefits. Some typical arrangements are described in more detail below. For more on the value of renewables to utilities, click here. Power Purchase Agreements Power Purchase Agreements (PPAs) are legal contracts between buyers and sellers of energy and capacity, and specify important details of the transaction, including the term of the contract and price paid for energy. When negotiating a PPA, environmental attributes, often called Green Tags or Renewable Energy Credits are usually sold with the power, but this must be specified in the PPA or it will be assumed that they are owned by the project owner. PURPA and Avoided Costs Net Metering
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Inverse magnetostrictive effect The inverse magnetostrictive effect (also known as Villari effect) is the name given to the change of the magnetic susceptibility of a material when subjected to a mechanical stress. Explanation[edit] Whereas magnetostriction characterizes the shape change of a ferromagnetic material during magnetization, the inverse magnetostrictive effect characterizes the change of domain magnetization when a stress is applied to a material. This magnetostriction can be positive (magnetization increased by tension) like in pure iron, or negative (magnetization decreased by tension) like in nickel. applied on a single magnetic domain, the magnetic strain energy density can be expressed as:[1] where is the magnetostrictive expansion at saturation, and the angle between the saturation magnetization and the stressed direction. and are both positive (like in iron under tension), the energy is minimum for = 0, i.e. when tension is aligned with the saturation magnetization. References[edit] See also[edit]
Ofgem guidance on collective purchasing & switching: thePeoplesPower 1st May 2012. Yesterday afternoon (30/4/2012) Ofgem wrote an open letter offering guidance on the legality of collective switching schemes. In general Ofgem “generally welcome” the development of collective purchasing schemes. Ofgem’s General conclusions All quotes on this page can be found in the Ofem Open letter on their website (PDF file) “Our general view is that the licence conditions that apply to licensed suppliers do not, in principle, prevent suppliers from engaging in collective purchasing and switching schemes.” and “Similarly, our general view is that the regulatory requirements under the RMR proposals would not prevent suppliers from engaging in collective purchasing and switching schemes.” (RMR – is Ofgem’s Retail Market Review – a consultation that has just been completed by Ofgem with the energy industry on how domestic supply should be reformed.) Want cheaper electricity?
Magnetic susceptibility In electromagnetism, the magnetic susceptibility Definition of volume susceptibility[edit] The volume magnetic susceptibility, represented by the symbol (often simply , sometimes – magnetic, to distinguish from the electric susceptibility), is defined in the International System of Units — in other systems there may be additional constants — by the following relationship, it is same as residual magnet. where M is the magnetization of the material (the magnetic dipole moment per unit volume), measured in amperes per meter, and H is the magnetic field strength, also measured in amperes per meter. The magnetic induction B is related to H by the relationship where μ0 is the magnetic constant (see table of physical constants), and and the magnetic permeability are related by the following formula: This allows an alternative description of all magnetization phenomena in terms of the quantities I and B, as opposed to the commonly used M and H. Conversion between SI and CGS units[edit] Examples[edit]
How to get lower energy bills: thePeoplesPower The concept is simple. Energy bills are really expensive for everyone, but as individual households we have no power to negotiate. thePeoplesPower believes that by negotiating together, we have the power to get a cheaper, fairer deal. (October 2013) At present we think people are better off switching NOW - and not waiting for another collective switch. (Find out more) We are offering £10 per fuel cashback whether you switch by internet or phone (Ofgem had said that all cashback were supposed to end by October 23nd – however, it seems that Ofgem have allowed cashback incentives to remain till December 31st). Switch Now! Switch Now! thePeoplesPower is a UK website where people can sign up their household for the cheapest electricity and gas. thePeoplesPower and our switching partner energyhelpline ask energy companies (the big ones as well as most of the smaller ones) to give us their cheapest energy deal. We will tell you how long you have to decide whether to accept the offer. Sign up NOW
Ferromagnetic resonance History[edit] Description[edit] FMR arises from the precessional motion of the (usually quite large) magnetization of a ferromagnetic material in an external magnetic field . The basic setup for an FMR experiment is a microwave resonant cavity with an electromagnet. Furthermore, the resonant absorption of microwave energy causes local heating of the ferromagnet. The resonant frequency of a film with parallel applied external field is given by the Kittel formula:[1] where is the magnetization of the ferromagnet and is the gyromagnetic ratio.[2] See also[edit] References[edit] Vonsovskii, S. External links[edit] References[edit] end fuel poverty