Conditions For Maximum Efficiency Research Articles

Basic concepts of spray dryer design

AbstractThe major parameters in the design of spray dryers are discussed. A Lagrangian approach, combining experimental data with theoretical concepts, is proposed to develop design methods. Vortex flow patterns, obtained experimentally in a laboratory size chamber, are correlated and presented.Based on this design methodology, computational methods are given to calculate droplet trajectories and hence to predict the optimum chamber dimensions and operating conditions for maximum thermal efficiency and/or minimum operating cost. Application of these basic principles is illustrated by the design of an industrial size, spray drying chamber for a specific feed solution and production rate.

Using Dimensionless Prediction Terms to Describe In-Soil Tracked Vehicle Performance

ABSTRACT j ABORATORY tests were con-1^ ducted with a single model track operating straight line at low speed in level test beds of air-dry sand and of near-saturated clay. Dimensionless terms composed of independent (con-trolled) track and soil variables were developed to predict track perform-ance in the two soil types. Four performance levels (the towed, self-propelled, 20 percent slip, and maximum tractive efficiency condi-tions) and five performance variables (pull, towed force, torque, sinkage, and trim angle) are considered. Validation tests indicate that both the sand and the (preliminary) clay prediction terms can be used to describe prototype vehicle perform-ance

Review on ultra-violet nitrogen lasers

In this paper, we present a review of the ultraviolet molecular Nitrogen lasers from their origin until 1974, these lasers being considered as the representative of UV lasers with pulsed electronic pumping and low pressure molecular gases. Principaly, are developped: the laser spectroscopy, the inversion conditions, a valuation of the power density and maximum efficiency, the amplification and oscillation conditions. So, the performances of different technologies are compared and analyzed.

Aspekty operační dopravy lahví jako předpoklad plynulého provozu lahvárenských linek.

Aspekty operační dopravy lahví jako předpoklad plynulého provozu lahvárenských linek.

Competition and Efficiency: Comment

A familiar argument asserts that competition results in the maximum possible efficiency in the use of resources; and therefore in this respect it is superior to central planning and monopoly and other market structures. Even such advocates of socialism as Oscar Lange (1938) and A. P. Lerner (1944) have conceded this claim and have urged that central planning be confined to investment. The traditional theoretical defense of competition emphasizes allocation, but maximum efficiency in the use of resources entails maximum technical as well as allocative efficiency, as many expositions recognize. Such expositions maintain either that the conditions of competition entail maximum technical efficiency, or, less formally, that produces this result. Recently Leibenstein (1966), Comanor and Leibenstein (1969), Scherer (1970), and Shepherd (1970) have argued that technical inefficiency may be the major loss from monopoly and so have given this issue greater prominence. The shift in emphasis away from allocative efficiency reflects the small estimates of the welfare loss resulting from monopolistic misallocation, which intensive examination for biases has not significantly increased (Scherer 1970, pp. 400-404). The shift also reflects the recognition that reasonable estimates of the monopoly effect on price and of the price elasticity of demand yield small estimates of the welfare loss. This paper examines the logic of the model and the argument based on competitive pressure and finds the case for maximum technical efficiency under competition deficient. We will see that even the more modest claim for the superiority of technical efficiency under competition than under alternative market structures remains questionable. Indeed, competition does not even guarantee that an inefficient technique will disappear. A by-product of the inquiry into the logic of the model is the negation of another major normative claim for competition-the claim that it eliminates excess profits. We will see that they can persist. This

Optimum second harmonic generation in inhomogeneous magnetoplasma

Analytical expressions have been obtained for the second harmonic component in the reflected and transmitted waves from an inhomogeneous magnetoplasma slab, having both electron density and temperature gradients, when an electromagnetic wave of frequency omega is incident normally on it. These expressions have been used to obtain optimum conditions for maximum conversion efficiency of second harmonic generation.

Optimum second harmonic generation in inhomogeneous plasmas

The authors have investigated the conditions for maximum efficiency of second harmonic generation in reflected and transmitted waves from a plasma slab when a plane electromagnetic wave is normally incident on it. It is concluded that the efficiency of second harmonic conversion in the transmitted wave is maximum when 0.7<( omega p/ omega )2<0.9 and dimensionless plasma slab thickness ( xi 0= omega z0/c) is in the range 3.2< xi 0<5.0 and that it is maximum in the reflected wave when 1.0<( omega p/ omega )2<3.0 and 3.0< xi 0<4.0. The variation of the efficiencies in these limits is not significant.

Optimum harmonic generation in plasmas

Using the expressions for the second and third harmonic components of the current density in a plasma, subjected to an external alternating field and a d.c. electric field, the authors have investigated the conditions for maximum efficiency of harmonic generation in a plasma. It is concluded that (i) the intensity of harmonics is higher in the transmitted component than in the reflected component from a plasma slab, and that (ii) the efficiency of second-harmonic conversion is maximum when 0·80 <(ωp/ω)2 < 0·90 and dimensionless plasma thickness (ξ0=ωz/c) in the range 3·20 <ξ0 <3·50 and the efficiency of the third-harmonic generation is a maximum when 0·80<(ωp/ω)2<0·95 and 2·50<ξ0<3·40. The variation of the efficiencies in these limits is not significant.

Small-signal impedance of avalanching junctions with unequal electron and hole ionization rates and drift velocities

A small-signal analysis of an avalanching semiconductor junction is presented for unequal electron and hole ionization rates and saturated drift velocities. The model consists of a thin ionization layer in a thicker depletion layer. The ionization rates are assumed independent of distance in the ionization layer and zero elsewhere. This analysis is an improvement of Read's, and is sufficiently realistic to predict most of the small-signal characteristics shown by the computer analysis of Misawa. The linearized differential equations describing the ionization layer are solved with the ionization rates perturbed by the ac electric field. The ac junction impedance is calculated from the solutions of the differential equations. Although the small-signal analysis does not predict the conversion efficiency of an avalanche diode oscillator, it does predict the threshold conditions for oscillation. It may also help predict the conditions for maximum efficiency through knowledge of the input power and the Q of the diode at the onset of oscillation.

On the design of a rotating field pinched discharge

The dynamics of a rotating field pinch are described in terms of the macroscopic quantities: temperature, pressure, plasma radius and magnetic field strength. The amplitude programme necessary for maintaining the pinch is established and heating rates are given. The energy transfer between generator and plasma is examined and the condition for maximum efficiency is derived. These are the relations upon which the design of an experiment should be based.

The electrodeposition of gallium from a chloride bath

The electrodeposition of gallium from a solution of the chloride has been investigated. The optimum conditions for maximum current efficiency are: 1. (i) concentration of gallium: 2.5–4 M. 2. (ii) cathode current density. 100 A dm 2 . 3. (iii) cathode potential: −0.6 to −0.7 V (cell voltage 4–5 V). 4. (iv) temperature : 40°–50°C. 5. (v) pH of the solution: 1.5–2.5. Under these conditions the current efficiency may be better than 80%.

Small-signal impedance of avalanching junctions with unequal electron and hole ionization rates and drift velocities

A small-signal analysis of an avalanching semiconductor junction is presented for unequal electron and hole ionization rates and saturated drift velocities. The model consists of a thin ionization layer in a thicker depletion layer. The ionization rates are assumed independent of distance in the ionization layer and zero elsewhere. This analysis is an improvement of Read's, and is sufficiently realistic to predict most of the small-signal characteristics shown by the computer analysis of Misawa. The linearized differential equations describing the ionization layer are solved with the ionization rates perturbed by the ac electric field. The ac junction impedance is calculated from the solutions of the differential equations. Although the small-signal analysis does not predict the conversion efficiency of an avalanche diode oscillator, it does predict the threshold conditions for oscillation. It may also help predict the conditions for maximum efficiency through knowledge of the input power and the Q of the diode at the onset of oscillation.

MHD直接発電の最大効率条件

Maximum efficiency condition of MHD power generation have been derived as follows:(1) Spacialy homogeneous distribution both of induced electro-motive-force and of the ratio of the applied magnetic induction to the density of a working fluid are required for irrespective of compressible or incompressible plasmas.(2) In case of incompressible plasmas, a homogeneous distribution of the magnetic induction is requested.(3) The magnitude of the required external loading at optimum and maximum efficiency power conversion is determined and it is proved that the optimum value of loading exists in a light load region.

The effect of source and sink thermal resistance on thermoelectric generator performance

A static analysis of the thermoelectric generator is necessary in order to specify the electrical loading condition for maximum energy conversion efficiency and to determine the corresponding efficiency. Ioffe has done this for the simple case of a single p-n junction thermocouple, and his analysis has been extended to include the effect of temperature dependent parameters by Borrego, Lyden, and Blair.1,2 Harman has considered a cascade generator and has shown how its design can be optimized.3

Frecuency Multiplication wilt Nonlinear Capacitors-A Circuit Analysis

This paper presents a circuit analysis of frequency multipliers employing nonlinear capacitors. The analysis applies to the case of a multiplier of any order using semiconductor nonlinear capacitors, and specifies impedance levels, power capabilities, and efficiency in terms of the characteristics of the nonlinear element and the associated linear network. From the formulas derived it is possible to specify the optimum nonlinear characteristic for a given circuit and harmonic number, and to calculate the conditions for maximum efficiency. The procedure is also applicable to frequency dividers, and to frequency multipliers employing nonlinear induct ance.

U-233 Breeder- U-235 Converter Reactor

A description of a fluid-fuel-fluid-absorber thermal reactor for the production of U233 is presented herein, and the conditions for maximum efficiency as a breeder (shortest doubling time) are elaborated. With very little modification of operating conditions and no modifications in the structure, the machine shows promise as an efficient U235-U233 converter, with the possibility also of by-product power. Some of the development work required is indicated. In particular, achievement of high pumping rates for maximum heat transfer and fabrication of very thin-walled zirconium tubing pay large dividends.

Efficiency Calculation Formula of Francis Water Turbines by their Model experimented Efficiency

It is the well known phenomena that the efficiency of full scale water turbine is better than that of model. And it has been considered as such only because of the difference of friction losses between full scale and model, by their difference of Reynolds' number. The author, considering the discrepancy of velocity diagrams between full scale and model, owing efficiency difference, and to arrange this difference to the efficiency calculation formula, deduced a new formula to calculate the loss independent of Reynolds' number. By this formula, considering also the difference of friction loss, the author presents a new type efficincy calculation formula of Francis water turbines by their model efficiency. It is applicable to the case of partial load, and involve the deviation of maximum efficiency condition between full scale and model. The several actual experimental results in Japan coincide closely with calculated full scale efficiency by above formula.

A Note on the Design of Ducted Fans

SummaryThe design of ducted fans, and the estimation of their performance for conditions other than those of the design, are usually based on the equations of the so-called strip-theory. Existing methods of solution invariably employ some form of iteration which is more or less rapidly convergent according to the experience of the computer and the detail of the method.In this note, a solution is given which, although it is strictly an iteration, is explicit in the sense that in practice no iteration is necessary. It is shown how both design for a given performance and performance for a given fan can be calculated in one direct step.Conditions for maximum efficiency are considered in an Appendix. Here a suggestion of R. Baldur's is used to give a simple approximate solution of the strip-theory equations which can be developed to give conditions for maximum efficiency, for the special case of a constant pressure rise through the fan.

Some Additions to the Theory of Radio-Frequency High-Voltage Supplies

The double-tuned overcoupled air transformer, commonly used in radio-frequency high-voltage supplies, is represented by an equivalent primary circuit. This circuit can be used very advantageously to develop the theory of operation of the oscillator, including the two possible operating frequencies, the necessary conditions for oscillation and maximum efficiency, and the variation of operating frequency and load resistance with primary tuning. It is shown that, at the operating frequency, the load impedance is purely resistive. The various resistances in the circuit representing the power losses and the load resistance are included in the equivalent circuit resistance, which appears as the plate load of the class-C oscillator tube. This greatly facilitates the design of a circuit to give any required power and voltage output. There are several ways in which this design problem can be approached, and the paper outlines the method which was used and found successful by the author.

A Rational Representation of the Flow Performance of Reaction Steam-Turbine Blading

Abstract This paper gives a condensed method of representing flow performance of reaction-type turbine blading which is applicable to an extensive range of flow conditions including those widely different from the conditions of maximum efficiency. The method is of particular value in analyzing flow in by-pass blade groups of central-station turbines or of mixed-pressure or bleeder turbines. It is based on dimensional analysis and empirical data are presented in the condensed form suggested by the analysis.