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Dr. S.R. Caplan (Israel) summarised his work on the self adaptive control of energy conversion and its relation to the mechanical behaviour of muscle.

Silicone fluids have numerous electrical applications in both energy conversion equipment and communications type apparatus. To aid engineers in the application of these fluids and to determine the general characteristics of these dielectrics, a study was made of their electrical properties. The measurements were made on fluids of commercial purity.

During a session of the first Intersociety Energy Conversion Engineering Conference, a panel discussion dealt with approaches to nonconventional energy conversion education. This short paper covers the contribution of this author. It is realized that these topics should be covered during university studies; however, the question of where in a curriculum, or when during a student's university career formal courses should be offered, has not yet been answered. The author suggests that only a small number of engineers are needed in this area, and that there is really no space in any undergraduate curriculum to give these topics the amount of time they require. Accordingly, the place for such studies is on the graduate level, at the very few universities which can expect to interest a sufficiently large number of students in order to develop and carry on a specialized program in an economical way.

As a result of the energy conversion and storage research underway at Oklahoma State University since 1961, several components needed to engineer a continuous-duty energy system operating on replenishable solar energy have been developed to the prototype stage and are being tested. This paper presents and discusses these components and how they fit together in the solar energy systems envisioned for the long-term and immediate future. A simplified economic analysis of solar energy systems is presented, and the calculated generation costs are compared with those of conventional fuel burning systems for different fuel costs, load factors and interest rates. One result of this study is that wind energy systems, costing $125 to $150 per installed kW and pumping power directly into a.c. mains for 20 per cent of the time using the field-modulated generating systems developed at OSU, are competitive with conventional systems costing $250 to $350 per installed kW operating at a load factor of 80 per cent and fuel cost of $0·50 per MBtu. More such comparisons are included in the text of the paper.

If the insulating layer in a metal-insulator-semiconductor (MIS) diode is very thin ( A for AlSiO2Si), measureable tunnel current can flow between the metal and the semiconductor. If the insulating layer is even thinner ( A ), tunnel currents are so large that they can significantly disturb the semiconductor from thermal equilibrium. Under such conditions, MIS diodes exhibit properties determined by which of the following tunneling processes is dominant; tunneling between the metal and the majority carrier energy band in the semiconductor, between the metal and the minority carrier energy band, or between the metal abd surface state levels. In the present paper, minority carrier MIS tunnel diodes are analysed using a very general formulation of the tunneling processes through the insulator, transport properties in the semiconductor, and surface state effects. Starting from solutions for diodes with relatively thick insulating layers where the semiconductor is essentially in thermal equilibrium, solutions are obtained for progressively thinner insulating layers until non-equilibrium effects in the semiconductor are observed. It is shown that such minority carrier MIS tunnel diodes with very thin insulating layers possess properties similar to p-n junction diodes including exponential current-voltage characteristics which approach the “ideal diode” law of p-n junction theory. The theory adequately describes the observed properties of experimental devices reported in a companion paper. The diodes have application as injecting contacts, as photodiodes or elements of photodiode arrays, and as energy conversion devices employing the electron- or photo-voltaic effects.

Over the last few years, considerable effort has been devoted to employing the plasma state in applications as widely differing as microwave and optical frequency devices; power generation by thermonuclear fusion; magnetohydrodynamic (MHD) and thermionic energy conversion, and the propulsion of spacecraft. In some of these areas intense activity still continues, and encouraging progress is being made. In others the results have been disappointing, and after an initial period of enthusiasm interest has waned. This paper is restricted to such an area, and reviews microwave plasma device research. A few years ago it seemed that a new and useful range of components, including phase shifters, beam-plasma amplifiers, and harmonic generators, might be developed. After a great deal of work, there is still a dearth of serious commercial plasma competitors to existing vacuum tube and solid-state devices. The paper discusses some of the obstacles to microwave plasma device development that have been encountered along the way, and some of the paths that have been taken to circumvent them. It is concluded that the present disappointing situation is likely to persist unless a major breakthrough is made in production of a simple quiescent plasma source, or there is a departure from the present device concepts.

This paper presents a brief outline of the various solid-state energy conversion concepts currently under development by the Air Force. Much of the paper will be on the developments in solar cells and thermoelectrics with only a brief look at piezoelectrics, pyroelectrics, ferroelectrics, the Nernst effect and nuclear photon conversion. These conversion concepts are discussed from the stand-point of present capabilities to satisfy aerospace vehicle electrical power needs together with the author's estimates of possible performance if the concepts are completely developed. The energy sources considered are solar, nuclear, chemical and acoustic with emphasis on solar and nuclear. Research and development is being accomplished in the areas of solid-state energy conversion today because these materials and conversion mechanisms are most nearly ideal for unattended operation in space. That is: they are relatively static (no moving parts); are non-volatile exceptat high temperatures; are reasonably resistant to the space environment; and generally have long lifetime possibilities. The long range objective of the applied research programs in these areas is to acquire the technology for obtaining reliable, highly efficient, long lifetime, light weight, and low cost energy conversion systems for aerospace vehicles. The lifetime requirements are for essentially unattended operation for two years by 1965 and for five to ten years by 1970. Generally high watts/lb, reliability, and long lifetime are the primary objectives, and efficiency and cost are of lesser importance.

This paper discusses the process of chemical regeneration of hot metallic surfaces, which may find application in very high temperature thermionic devices. In the process, gaseous materials such as chlorine form compounds with the metal departing from the hot emitter surface. The metallic compounds return the metal to the emitter surface where it is redeposited. The paper consists of an analysis of chemical regeneration under conditions of free molecule flow (Knudsen conditions) in which particles are assumed not to interact in the interspace. Partial or complete equilibration is assumed at the walls, the degree of equilibration being expressed by a recombination coefficient, γ. The analysis prescribes conditions within the system required to prevent destruction of the surfaces. A simplification of the analysis yields a thermodynamic criterion for selection of materials to be tested in regenerative systems. Some hypothetical systems are considered as examples. These are: tungsten-chlorine, molybdenum-chlorine, tungsten-molybdenum-chlorine, and tungsten-oxygen. The possible difficulty in constructing a stable device with an emitter and collector of the same material is discussed, together with a solution to the problem. No consideration is given to the possibility of destruction of other parts of the system by the reactants used to regenerate the emitter and collector. Chemical interactions between species added to the interspace for their regenerative properties and materials added for their effect on electrical properties are not considered.

Although the title of this paper, as chosen originally, is broad enough to allow consideration of both magnetohydrodynamic generators and accelerators, the present discussion will be limited to MHD power generators. The subject of plasma propulsion (MHD accelerators) is discussed in another paper presented in this symposium [see Physics Today, March 1963, p. 24].

With the advent of gas turbine prime movers for both propulsion and electric power generation, new methods of optimizing thermal efficiency are needed if weight and cost limits are to be achieved by new ship designs without sacrificing operational capability. The balance of primary power generation from fuel and secondary power generation utilizing other energy media must be reviewed. Where once the basic shipboard energy conversion was Bunker C fuel into steam within a large boiler, using steam as the energy medium for all power and heating use, we now have machinery systems that convert fuel into energy at several subsystem levels, i.e. propulsion, electric power, auxiliary steam and so forth. The design challenge for today's machinery system engineer is to optimize thermal recovery from fuel much the same as economizers, etc. that were used in previous steam plant designs. This can be done by making one system dependent upon another for its source of energy. However the design constraint demanded by NAVY combatant ships is that operational flexibility, vulnerability protection and reliability/maintainability/availability goals for each dependent system must be maintained should the primary energy source system fail. This paper presents an engineering approach to generating and evaluating alternative machinery designs within the structure of a set of ship design criteria categories. These categories are defined and examples of machinery system design objectives given. A design process is then proposed which includes determination of energy requirements, identification of alternate energy generation/conversion hardware and verification of adequate energy supply under all operating modes. Discussion is given to the importance of selecting the proper energy medium (fuel, electricity, steam, etc.) for each functional service if energy generation and energy absorption are to be efficiently matched. An evaluation approach is then presented which compares total performance of candidate designs on a system-level basis. Finally, the paper describes two recent ship designs where integration of machinery systems has taken place: the Canadian DDH-280 Class Destroyer and the U.S. Navy DD-963 Class Destroyer. Elements in the “trade-off” studies for these ships are reviewed and design advantages discussed.

Nuclear technology interacts with laser technology in two ways. Lasers may be used for generation of nuclear energy in connection with laser triggered thermonuclear fusion reactions or nuclear energy may be used to excite lasers. This paper is concerned with the latter possibility. The ultimate goal is to directly convert fission energy, the largest part of which is the kinetic energy of charged particles (fission fragments), into laser light. Historically this idea is almost as old as the laser itself. Papers dealing with this subject began to appear around 1961. A review of this earlier work is given in [1].

HE process described in this paper, has the objective of adding energy to test air flows to help simulate re-entry and space shuttle conditions without exceeding pressure and temperature limitations of the air supply. Electrofluid dynamic (EFD) acceleration is involved, whereby kinetic energy is added to the flow by the volume forces resulting from interaction between a strong electrostatic field and small charged particles imbedded in the flow. The charged particles are removed before the test section is reached so that the test flow is not contaminated. This process is described in more detail in the revised version of the AIAA paper. The objective is to present generalized analyses of EFD augmentation for facilities applications.in order to show promising areas for exploratory research. Contents A schematic diagram of the electron1 uid dynamic augmented wind-tunnel (EFDAW T) system as a whole is shown in Fig. 1, with the following principal parts: a) high pressure air supply, b-d) high-voltage EFD power supply, e) EFD acceleration section whereby unipolar charges are strongly accelerated by a high-voltage electrostatic field, f) final expansion nozzle which expands the flow to the desired test section conditions, also collecting and neutralizing the charges, g) test section, and h) exhaust section. The EFD generator, Sec. d is being developed by the Energy Conversion Laboratory of the Aerospace Research Laboratories, which has been active for a number of years in the direct conver

In this paper we present the results of an experimental study of electronic energy transfer in xenon‐argon and xenon‐krypton gaseous mixtures excited by an α source. Spectroscopic evidence is presented for molecule‐atom energy transfer from Ar*2(1,3Σu) to Xe(1P1) and from Kr*2(1,3Σu) to Xe(3P1). These two electronic energy transfer processes are characterized by large ∼ 10−14 − 10−13 cm2 cross sections. Information has been obtained for collision‐induced energy conversion processes of the Xe energy acceptor involving 1P1 → 3P1 conversion and the formation of Xe*2(1,3Σu) at moderately low (≤ 200 ppm) Xe concentrations. A new emission band, observed in the xenon‐krypton system, peaking at 1530A, is tentatively assigned to a heteronuclear (KrXe)* diatomic molecule.

Some general problems of design and application of compact devices for the generation of pulse electric fields at a megavolt range in space experiments are discussed. The prospect of various applications of powerful electron beams for active diagnostics of upper layers of atmosphere, radiation belts and the earth's magnetic field is also reviewed. The proposed development of powerful impulsive devices is dictated by limitations of energy resources in spacecraft together with a need to get a good signal-to-noise ratio for reliable data recording. Compact devices which directly transform electric energy of a low-voltage source (solar batteries, chemical elements, nuclear reactor, etc.), into the energy of a megavolt charge particle beam of high impulsive power appear as reliable means for satisfying these requirements. In this paper, the basic practical schemes of energy transformation procedures are considered and the optimal operation parameters of high-voltage storage and transformer systems are discussed. Proper application of combined high-voltage insulation techniques result in the development of experimental models of heavy-current electron beam accelerators capable of generating beams of 300–500 kV, 3–5 kA, with a pulse duration of 15 × 10−9 sec at a frequency of 10 Hz. Typical applications of electron beam accelerators including the generator of electron-beam-controlled discharge laser beams are also described.

Since the beginning of earth, ultra-violet rays from the sun have been splitting water molecules in the upper reaches of the atmosphere, producing hydrogen and oxygen. At the same time, photosynthesis has been sustaining life on earth by utilizing the longer wavelengths of sunlight to split carbon and water molecules forming carbohydrates and oxygen. Attempts are being made to imitate these processes for the purpose of harnessing solar energy for man's use. This paper presents a state-of-the-art review of photolysis of water by sunlight with consequent energy storage in the molecular bonds of hydrogen and oxygen. The photocatalytic solar energy conversion methods reviewed are classified according to the photosensitizer type. That includes catalysts such as compound salts, compound semi-conductor crystals and photosynthetic dyes. An assessment of these methods concludes that photolysis of water as a solar energy conversion process does not seem feasible at present or for the immediate future. On the other hand, efficiency estimates indicate that with research emphasis this unconventional energy conversion method may prove to be a long-term alternative in harnessing solar energy for man's use.

Multimegajoule high‐temperature high‐Z plasmas are of interest as high‐intensity radiation sources for use in a number of applications. This paper describes a possible method of generating such plasmas by means of the j × B driven implosion of thin metallic foil cylinders. Basic analytical guidelines are developed and the results of numerical computations are displayed. Experimental problems associated with the creation of high‐energy plasmas by this technique are discussed with some initial experimental results presented.

This paper contains a study of the energy conversions in Pedlosky's solution for finite-amplitude baroclinic wave development for the case of small dissipation. It is shown that the solution contains an implicit, non-physical source of mean kinetic energy owing to the neglect of a certain boundary condition on the developing mean flow. Additional features of the energetics are described which do not depend explicitly on the solution with the relevant boundary condition inserted. However, the possibility of limit-cycle solutions when this boundary condition is satisfied remains an open question.

This paper presents procedures for designing the transformer for a two-winding energy-storage dc-to-dc power converter in which the power transistor is pulsewidth modulated by means of a constant-frequency type of controller. The presence of the second winding provides an additional degree of freedom in the design procedures beyond those for single-winding converters and leads to a number of design options for achieving specific performance characteristics. Ten options are provided: four relate to conditions that may be imposed on the duty cycle, four to maximum stress on the semiconductors, and two to the transformer turns. The design algorithm has been implemented in a computer program to automate the design procedures and to provide an evaluation of the converter circuit for each of the transformer designs.

This paper describes a program directed toward eliminating the need for a stator seal in turbine-driven space power generators that are required to operate in an energy conversion loop using liquid metals such as mercury and potassium Stator seals may be one of the major development problems affecting the reliability and design of space power generators. The need for higher system reliability and improved generator design optimization is the compelling reason for the effort towards eliminating the stator seal requirement. Development of a generator insulation system and winding configuration that permits direct exposure of the generator stator to a liquid-metal-vapor environment was the initial objective of the program, and development of a generator that incorporates the unsealed stator concept is the ultimate program objective.

The expected philosophy in the future trend for energy conversion on a large scale is outlined in this paper. Following a brief review of the basic concepts of irreversible thermodynamics a scheme is described which outlines a method of searching for new conversion processes. Some examples are then given to demonstrate the method.

Internal energy can be pictured as the energy contained by quiescent matter because of particle motion—the thermal energy—and because of particle interaction—the chemical energy. Attempts to separate these two parts thus far have yielded only qualitative discussions with no logical formulations. In the present paper, definitions of chemical available energy and thermal energy are justified and expressions for these new properties and their changes are rigorously developed. First, thermodynamic friction is defined to include not only the usual mechanical form, but also forms called here the chemical and thermal friction. Then, the concepts of chemical available energy, thermal available energy and thermal energy are defined, and the equations of change for these new properties are developed. It is proved quantitatively that mechanical and chemical friction are, respectively, the irreversible conversion of mechanical energy and chemical available energy into thermal energy of less availability, while thermal friction is the degradation of thermal energy through temperature gradients. The equations are applicable for chemically reacting or non-reacting fluid systems, with or without diffusion. The developments have been restricted to systems with conservative body forces, alike for all species, to avoid distracting attention from the main thesis: the mathematical and physical relationships between friction and available energy. 1

As bearing on the general problem of conversion from steam to electricity for railroad operation, attention may be drawn to the probable influence of the methods followed and results obtained in equipping single-track roads. Of the total mileage in this country, about 60% is single track. The conditions obtaining on such roads are necessarily widely different from those on the large trunk-line sections which have been recently electrically equipped. While the several notable papers which have recently appeared on this and kindred subjects have taken quick advantage of the data available from the short periods of operation of several large installations, it cannot be said that the conditions in those cases are typical of more than a part of the entire problem.

After a brief survey of proposed radioisotope conversion systems this paper presents in detail two systems particularly suited for microwatt power sources. First, a 10-9 ampere Kr85 s current cell capable of tens of kilovolts now in limited production is presented, followed by a discussion of other possible future s current cells. Second, some theoretical considerations of a Pm147 silicon electronvoltaic converter with an output in the range of 100 ?A/cm2 at a few tenths of a volt are discussed. Some applications adapted to each system are also presented.

This paper explores the potential applicability of the Supercritical (Feher) Thermodynamic Power Cycle to advanced ground nuclear power systems. The supercritical cycle is a closed cycle heat engine that operates entirely above the critical pressure of the working fluid. It is characterized by high thermal efficiency and compactness of the machinery. The cycle is highly regenerated and receives heat over a narrow temperature range. For the evaluation of the advantages of the power conversion concept, a 150-kwe power conversion module has been selected that employs a gas turbine driven high speed alternator, using carbon dioxide as the working fluid.

In this paper we show that for an exciton mode coupled to a vibronic state of an impurity or to a different electronic final state of a host molecule (through an intersystem crossing or internal conversion) where the final state is damped, the damping causes a broadening of the initial exciton mode. The damping is considered in terms of Senitzky's theory of the damped quantum oscillator for molecular vibrations and in terms of his theory of the damped two‐level system for the molecular electronic states. The damping constants found in the Senitzky‐type damping theory are related to Green functions. Thus, it is possible to relate the exciton linewidth (or lifetime) to well‐defined energy conversion processes within a molecule. The final energy‐loss step—to the thermal bath—can still be treated by means of an arbitrary damping constant.

The present paper is concerned with an evaluation of a piezoelectric energy conversion system in which two columns of piezoelectric ceramic disks are excited axially by means of thin metallic shims stacked alternately with the disks. Mechanical energy output is extracted through the expansion and contraction of the Columns. The treatment is based upon the equivalent circuit approach first suggested by Mason. A lever system is used in making the mechanical impedance transformation between the very high force and small displacement of the piezoelectric columns and the low force and relatively large displacement required for an artificial heart. The role of mass loading in improving the power capability and efficiency of the energy converter is clearly indicated. It is concluded that the theoretical energy output per unit mass of material per cycle and the efficiency of conversion are such as to justify a continued developmental effort.

This paper discusses certain of the noise characteristics of silicon broad area junctions which have been developed for use for solar energy conversion. Under constant illumination the photovoltaic output of these junctions has been found to show fluctuations which are characteristic of a 1/f noise power spectrum. For varying illumination the magnitude of the photovoltaic noise voltage has been found to vary considerably, and in fact passes through a pronounced maximum. A plausible explanation of this effect is obtained by assuming that fluctuations are produced in the primary photocurrent as a result of traversing the junction. The assumption of a current dependent noise mechanism is justified by an independent experiment.

In this paper the graph of potential against resistance, often used to picture the discharge of an electric cell, is shown to represent the transformations of energy involved in the process. With this property in view, the V-R diagram becomes applicable to every energy transformation that can occur in an electric circuit. Such a diagram is used accordingly to represent the charging of a storage cell as well as its discharge, the charging of a condenser, the operation of the dc generator and motor, the performance of the copper-iron thermocouple, and the increase and decrease of current in an inductive coil without iron. It is hoped that this unified treatment of important electric processes may reveal their essential similarities and make them better understood and more easily remembered.

The chain reaction which takes place in a nuclear reactor is a regenerative process and can therefore be unstable, so the fission rate must be closely controlled in order that the nuclear reaction may proceed at a rate which is both useful and safe. Electronic circuits play a vital part in this, and their reliability must be exceedingly high, as many reactors are required to run for months without interruption and for years without an unscheduled shutdown. This paper considers in a very elementary way the dynamic behavior of a reactor and the circuit requirements associated with maintaining the power level constant. The additional problems associated with starting-up and the automatic shutting-down of a reactor are briefly surveyed and the use of automatic data-handling is considered. It is concluded that not all instrumentation and control problems presented by existing types of reactor have been satisfactorily solved and that more advanced reactors will present still more difficult problems.

The evaluation of the effect of a transverse electric field on the characteristics of an EHD generator is an important problem of electrohydrodynamic energy conversion [1,2]. This subject was considered in [3,4] on certain simplifying assumptions, such as; absence of compressibility and zero mobility of charged particles. This paper gives a qualitative analysis of a stationary one-dimensional electrohydrodynamic flow of a compressible gas in the presence of mobile charged particles in a varying electric field having longitudinal and transverse components.

This paper considers the transient cooling of a spherical mass of high-temperature gas which is surrounded by the cold atmosphere. The ionization and dissociation phenomena are neglected, and it is assumed that energy transfer by convection is negligible in comparison to radiation. The radiation transfer problem has been formulated exactly. For the case of a gray gas, approximate solutions are obtained for the temperature inside the sphere as functions of time and space coordinate by the method of moments. The local radiation flux is then evaluated for two different initial temperature distributions and several value of the optical radius.

Ion engines have been found to be demanding loads for high-voltage solid-state power-conditioning systems. This is due, in large part, to the tendency of these engines to undergo frequent and severe electrical arcing. The unusual ruggedness and efficiency requirements for such power systems are in direct conflict with the requirement for an extremely light weight. This paper describes a six-stage nondissipatively-regulated modular conversion system in which the use of an unconventional method for accomplishing dc-to-dc conversion, current-feedback base drive for the power transistors, and a relatively high (10 kc/s) intermediate conversion frequency results in an efficient and lightweight power-conditioning system with excellent protection characteristics. In this modular 2000-volt 1600-watt system, voltage conversion is accomplished by means of multiple-winding energy-storage transformers, each containing a core with an air gap. These transformers are caused to absorb energy from the source on one half cycle and to discharge energy into the output filter and load on the succeeding half cycle. This configuration makes possible a converter in which no semiconductor element is subjected to an immediate or abrupt transient as a result of a short circuit across the high-voltage output; protection schemes need not be elaborate. This ?energy-pumping? conversion technique, in which the special energy-storage transformers perform multiple functions involving not only voltage conversion but also filtering, nondissipative regulation, and system protection, results in a system which is physically very simple.

Although it is proved theoretically that a two-parameter model is capable of converting potential energy into kinetic, there has been some doubt about its ability to predict successfully the strong cyclogenesis often associated with this energy conversion. The experiment described in this paper is intended to be a contribution to the solution of this problem. A two-level primitive equation model with constant static stability has been integrated for two cases characterized by typical baroclinic developments, and the results are compared to the barotropic forecasts for the same cases. The two-level prognoses are not better than the barotropic in many respects, but they show that at least some baroclinic developments can be predicted by this model.

In certain space missions a mirror is used to convert solar energy to forms suitable for use in a space craft. Effective operations of such a system requires accurate following and an initial acquiring of the sun. This paper describes a method based on momentum exchange from rotating flywheels to a platform to initially acquire the sun.

Thermomagnetic power devices utilize the temperature dependence of magnetic moment to convert heat into organized energy. In an analogous manner thermoelectrostatic devices would utilize changes of electric moment to perform the same function and the analysis of each can be given in a single treatment. This paper, which analytically explores new considerations relevant to these energy conversion methods, is motivated by a search for increased performance. To begin, a basis for the treatment of the thermodynamics of polarizable substances is developed in a manner that stresses material parameters. Explicit thermodynamic functions are then derived corresponding to both a simple and a realistic equation of state. With this information power cycles are devised and evaluation is made of their thermodynamic efficiencies. An optimum regenerative cycle emerges and criteria for its attainment are considered. Finally, a power estimate accounting for thermal irreversibilities predicts the possibility of low specific weight. Using more general conversion techniques than were admitted in the past, the prospect for thermomagnetic and thermoelectrostatic energy conversion is greatly improved.

The paper discusses problems and applications of plasma physics and its revelance to astrophysics. A method of interpreting radio emission of variable quasars is suggested. (Author)

This paper presents in depth the major basic performance characteristics of electrofluid dynamic (EFD) energy conversion processes, which are shown to be complementary to magnetofluid dynamic processes. With a view toward making possible effective thermal-electric energy conversion without moving parts, the potential compatibility of incorporating low pressure ratio EFD processes into high pressure ratio thermodynamic cycles is shown. Investigations of scaling, similarity, performance characteristics, and the effects of physical properties of working media containing electric charges of one polarity are used as a basis to determine the major problems and corresponding research areas in EFD energy conversion. In general these are: Generation of Charged Colloids; Electrode and Conversion Duct Geometry; and Fluid Dynamic Energy Transfer Phenomena in Multicomponent, Multiphase Flows. Also given are typical configurations of EFD energy converters, and a look at potential applications, especially those associated with encapsulated, long-duration power supply for operations in space, under the ocean, or at remote unattended sites.

This paper deals with the enhancement of the quantum efficiency and photovoltaic energy conversion efficiency of a p-n semiconducting cell by optimizing the dimensions of the cell. Based on the Shockley-Read statistics a general expression for the quantum efficiency of monochromatic incident radiant energy photons has been derived in terms of the absorption coefficient of the incident photons, the minority carrier diffusion length, the built-in electrostatic field appearing in diffused cells, and the surface recombination velocity in the exposed layer of the cell. Although the expressions derived may be used for all semiconducting p-n cells, special efforts have been made in the analysis and computations of the germanium p-n cell. The germanium cells show a great potential for photovoltaic energy conversion from radiant sources other than the sun. The results for germanium indicate that the quantum efficiency strongly depends upon the thicknesses of the exposed and base layers. The built-in electrostatic field and the surface recombination velocity in the exposed layer influence the quantum efficiency greatly. Optimization studies for the thicknesses of the exposed and base layers of an n-p type germanium for different values of minority carrier diffusion length, built-in electrostatic field, and surface recombination velocity have been worked out.

Mechanical properties of mechanochemical materials have been scarcely investigated. This paper deals with the theoretical and experimental studies on the mechanical behaviors of mechanochemical materials in an equilibrium state. That is, the degree of swelling under external forces and the works developed during the swelling of mechanochemical materials in forms of a particle, a film and particles in a rigid cylinder are treated from the engineering point of view. The expressions of the mechanical works are derived. Several other mechanical characteristics such as the degree of swelling, the restriction of energy conversion due to an external force, the work efficiency and the swelling pressure are also quantitatively explained. Comparison of the present materials with the muscle is made.

Normally the energy conversion efficiency of a confined-discharge plasma generator is inversely related to the mean enthalpy of the effluent plasma jet. The present paper describes a technique for increasing both the energy conversion efficiency, defined as the net fraction of the electrical power input transferred to the working fluid, and the mean enthalpy, defined as the net energy transferred to the working fluid per unit mass. A portion of the working fluid is introduced to the discharge through a narrow circumferential slit in the confining duct wall. Heat transfer and fluid dynamic effects associated with this high velocity inflow of cold gas cause the local discharge column to become highly constricted. Concomitant with this local fluid constriction (LFC) is a sharp increase in the local power density, resulting in enhanced energy transfer to the cold gas. Experimental results suggest that for optimum operation the gas injection slit should be located slightly upstream of the axial position where the discharge becomes thermally fully developed.

Continued development of the high vacuum tube has played an extremely important part in the development of radio communication. Since the power output of a tube is proportional to the amount of heat that may be dissipated safely from its anode the anode is one of the most vital parts of high vacuum tubes especially those used for transmitting purposes. Several materials have been found suitable for the anodes of transmitting tubes, depending upon the requirements of specific applications and the type of cooling adopted; these materials and their characteristics are discussed in this paper.

In many chemical operations for which large scale reactors must be designed, the rate of reaction is influenced by the fact that chemical and physical processes may proceed with comparable rates. This leads to considerable difficulty in constructing appropriate models for studying the behavior of reactors. In this paper, a few representative techniques which have been found useful are described, and compared with methods for modeling combustion chambers.

This paper discusses the part solar energy, our only energy income, can play in meeting our ever increasing energy demands. The basic characteristics of solar energy and the solar properties of materials are mentioned. The conversion of solar energy to the forms of energy which are needed in our daily life are explained.

The experiments described in this paper were initiated for the purely practical purpose of securing data to be used for an energy balance of the process of comminution of solids. The technologic problem is not considered here but rather the antecedent fundamental and scientific one of attempting to describe the thermodynamic properties of crystals as a function of particle size. It has been customary to ascribe observable variations in the properties of crystalline materials of large or fine particle size to a change of free energy, entropy or heat content resultant from the subdivision. Consideration of the first law of thermodynamics with reference to the application of work energy to crystals allows for only two obvious possibilities: (1) The heat produced in the crystals by the applied work is equal to it, whence no change of intrinsic energy of the material can occur; or (2) part only of the work appears as heat and the intrinsic energy of the crystals must increase. In this latter case, it is supposed that the energy corresponding to the increase of intrinsic energy is ``stored'' in the surficial layers of the crystal particles. We shall offer no apology for approaching the problem of testing these alternatives in a strictly empirical manner and for presenting data which may seem to contradict much of previous theory and experiment concerning the ``surface energy'' of solids. However tempting a review and criticism of previous attempts to measure or theoretically define this quantity might be, the elementary approach represented by our work now seems essential for understanding of the anomalous results, both of ourselves and others. Experimental test based on the first law, as expressed above, obviously could be either by (1) attempting to determine the change of intrinsic energy of fine compared to coarse particles of suitable materials or (2) by comparing the work and heat during the comminution process. Both of these experimental alternatives are described below. Thus we shall first describe experiments upon the heat of solution of fine and coarse calcite, designed to reveal measurable differences of intrinsic energy due to comminution. Further, we have investigated the specific heat at low temperatures of similar samples of calcite, and later of finely drawn wires of copper and aluminum in the annealed compared to the cold‐worked state, referring to that part of the intrinsic energy represented by heat content. Finally, in the case of copper and aluminum, we have adopted the second experimental alternative of comparing the work and heat during a drawing process.

The primary objectives of this paper are: 1. To present an available energy balance reflecting the Second Law of Thermodynamics to complement the macroscopic balances of Bird which are dictated by conservation of mass, the laws of motion and the First Law of Thermodynamics. 2. To develop an equation which relates the loss of available energy to the entropy production. 3. To point out that the dead state (the state of zero available energy) is a variable for the open system. The equations are valid, in general, for chemically reacting or non-reacting systems, with or without diffusion. Although the potential energy term implies like conservative body forces on each constituent the equations can be extended to include unlike and/or time-dependent body forces; this is accomplished with the generalized definition of potential energy presented earlier ([7], first footnote).

The flow in diffuser of the steam ejectors consists of the two processes, one of which is to mix steam with inhaled gas and the other is to transform the energy from the velocity of flow into the pressure. But in the theories of the steam ejectors, usually, the mixing process is. neglected, so that these theoretical methods are, as pointed out by Dr. Stodola, of little value for the ditermination of the dimensions in an actual case for the following reason : We do not know to what extent the velocities in a cross-section are equalized. Consequently, neither an exact energy equation nor a continuity equation can be formulated. So the author tried a calculation method of the flow in diffuser of the steam ejectors by thermodynamic consideration in which the two processes, not only the energy transformation process, but the mixing process, are considered. And he has made clear the various changes of flow state in diffuser and the causes of the so-called hysteresis phenomena of steam ejector. By this consideration, the two required conditions have been obtained for high vacuum in mixing chamber. (high vacuum characteristic) On the thermodynamic method, we meet with a difficulty, as also pointed out by Dr. Stodola, that the flows are of different kinds (steam and air). But this difficulty has been solved in this paper by drawing up i, s-diagrams for each air ratio, so that the various changes of flow state are shown on these diagrams.

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.

In contracting muscle a chemical reaction takes place in such a way that part of the free energy of the reactants can be converted into mechanical work. Recently Caplan (1965, 1966) has made a theoretical study of certain types of energy converters, using the methods of irreversible thermodynamics. He has extended this study to muscle and he makes several predictions of practical importance, notably about the efficiency of muscular contraction. In this paper a simplified summary of Caplan’s theory is given, with the equations rearranged, as far as possible, to provide relations between experimentally observable quantities. Four tests of the theory are then possible, of which the results are: 1. The theory correctly predicts the shape of the force-velocity curve. 2. The theory predicts a relation between the maximum efficiency of energy conversion and the degree of curvature of the force-velocity curve which is probably similar to what is found experimentally. 3. The theory predicts a relation between the force on the muscle and the rate of the driving chemical reaction which is markedly different from that which can be inferred from measurements of heat and work production. 4. The theory requires that there should be large variations in the free energy change of the driving reaction when the force on the muscle changes. It is difficult to see how these could occur in practice. No simple modification of the theory seems to avoid these difficulties. It is concluded that muscle is not an energy converter of the type described by the theory.