Energy Losses In System Research Articles

Comments on gravitational radiation damping and energy loss in binary systems

Comments on gravitational radiation damping and energy loss in binary systems

Measurement of damping in polymer materials

Damping materials dissipate mechanical energy when cyclically strained by converting it to heat. For sinusoidal strain the amount of energy dissipated per cycle depends on temperature, frequency, and amplitude. Each of these should be measured and reported. If the energy dissipated is proportional to the square of the amplitude, the damping mechanism is called linear and the damping may be reported as energy per cycle loss as a function of amplitude, storage, and loss modulus, or storage modulus and loss ratio. The measurement of system energy loss may be made by direct measurement of force, deflection, and the phase angle between them. The energy loss may also be inferred from the rate of decay in free vibration, the electrical impedance of or the energy input to a vibrating electromechanical system of which the specimen is a part. Regardless of the method used, it is impossible to distinguish between the energy dissipation in the specimen and that dissipated elsewhere in the system. This latter must either be accurately known or negligibly small. In order properly to interpret the data, the state and distribution of strain must be known though the volume of the specimen. Methods for measuring and controlling each of these parameters will be discussed and illustrated.

Flows Split in Closed Loops Expending Least Energy

In any problem involving flow distribution in a closed loop system, the flows distribute in such a manner that the loss of system energy is minimum. When this happens, head losses in alternate routes also become equal. Results obtained by the concept of least system energy loss agree with those obtained by the Hardy Cross method.

Energy efficiencies of air pollution control devices

The paper examines the minimum energy requirements for removing gaseous and particulate pollutants from gas streams at various levels of collection efficiency. A comparison of the minimum work with the actual work for typical particulate and SO 2 removal systems is presented. Equations for calculating the energy efficiency (effectiveness) of the various control devices are given as a function of both system energy losses and operating and maintenance costs.

Energy losses in a gas-particle system due to the irreversibility of interphase heat transfer

The energy losses in a dust-gas suspension due to heat transfer between the gas and solid phases are found by the methods of the thermo dynamics of irreversible processes. An expression is obtained for the energy losses in the approximation of the thermal relaxation time of the particle.

Energy Losses in a Many-Body System

The energy loss problem is formulated in such a way as to include all losses simultaneously. The lifetime and energy losses of a particle in a well- defined single-particle state with small transition probability are found to be related to the self-energy operator. As an illustration of the application of the relation obtained, a derivation of the Bethe sum rule and the Cerenkov losses is given for a particle incident on a many-body system. (auth)

Solar Collectors for Use in Thermionic Power Supply Systems in Space

T HERMIONIC conversion of solar energy to electrical energy is a commonly proposed means of generating sec­ ondary power in a space vehicle. The idea hinges on the use of a reflecting collector which concentrates solar energy onto the hot surface of a thermionic diode or series of diodes, where the conversion takes place. The heat thus accumulated passes through the converter and is dumped into space by the exterior radiating surface of the con­ verter package. The method of energy conversion is not of interest here. Suffice it to note that the temperature on the inner surface of the diode must be very high because the efficiency of the converter is sensitive to the available tem­ perature difference across the two diode plates. It has been found that the most practical form of concentrator which is capable of producing the necessary diode inner plate tempera­ ture is a parabolic mirror. Present thermionic converters have relatively low effi­ ciencies, but systems of the foreseeable future are expected to convert 10% or more of the solar energy entering the con­ verter into usable electric energy. To provide sufficient auxiliary power without exceeding space and weight limita­ tions, it is apparent that energy loss in the collector system must be reduced to an absolute minimum. The purpose of this paper is to discuss what these collector losses are, and to examine means of improving the overall collector efficiency.