Showing papers on "Literature survey published in 1974"

The Effectiveness of Alternative Instructional Media: A Survey

Abstract: This survey provides an overview of research on the effectiveness of alternative instructional media. The media discussed are traditional classroom instruction (TI), instructional radio (IR), instructional television (ITV), programmed instruction (PI), and computer-assisted instruction (CAI). The effectiveness of these media is examined from a reasonably macroscopic point of view; the psychology of pupil-teacher interaction or the 'content variables' of ITV, to take two examples, are at a micro-level not considered. Achievement test scores constitute the measure of effectiveness most frequently used in this survey though, where available, results concerning the affective impact of the various media of instruction are included. Achievement test data, in most cases, were collected only on an annual basis, so they reveal no fine-grained detail about the learning process. Since this survey is relatively brief and its scope broad, a few caveats are in order. First, where literature surveys are available, their results have been cited to the extent possible and, frequently, original sources remain unchecked. Second, available knowledge of the effectiveness of the various media varies considerably; much more is known about TI and ITV than about the others. For this reason a survey such as this is inherently spotty in its conclusions. The third warning, related to the second, is that many of the evaluations fall short of (or lack entirely) scientific standards of analysis and reporting. For this reason, it was sometimes necessary to attempt to cull conclusions from essentially journalistic accounts of projects. Fourth, it should be noted that this survey is limited to instruction within a school setting. Finally, the survey excludes information on costs. Before beginning the literature survey, we present a paradigm for measurement of effectiveness and then discuss several less desirable alternatives that have actually been employed. In the surveys of the individual methods where adequate prior surveys are unavailable, results from a representative sample of individual evaluations are discussed.

Informative and Goodwill Advertising

Abstract: T HIS paper attempts to show that there is merit in the long-standing but much abused distinction between 'informative' and other types of advertising, and that this difference is revealed in a differential effect on economic performance. After a brief literature survey, section II develops a theoretical distinction between informative and goodwill advertising. Section III outlines a test of the hypothesis that the different kinds of advertising will have opposite effects on market performance. Section IV presents the results of this test. Section V summarizes and relates the results to other recent work on the economics of advertising.

Ultrasound Dosage for Nontherapeutic Use on Human Beings - Extrapolations from a Literature Survey

Abstract: A practical method for analyzing the biological effects of nontherapeutic ultrasound was applied to the data of 21 different principal investigators. The data were compiled so that individual investigators could develop tentative guidelines of their own regarding the hazards of diagnostic ultrasound in human beings. One set of guidelines developed suggested that exposures of minimal hazard lie below a log/log line connecting 100 ?s of 100 W/cm 2 ultrasound with 200 s of 100 mW/cm 2 ultrasound. An ultrasonic intensity of 100 mW/cm 2 or less was of little or no hazard for at least 10 000 s. These guidelines applied to both continuous- and pulsed-wave ultrasound doses that were described by average intensity multiplied by total exposure time. The proposed schedule was valid for 0.5-15 MHz and for all anatomic sites except the eyes.

Mass-transport problems and some design concepts of electrochemical reactors

Abstract: Electrochemical cells, designed to operate with reactants at low concentrations, require special provisions to be made for enhancement of mass transport of the reactants to the electrode surface. The different concepts for doing this in industrial or large-scale cells are reviewed. Examples are given of cells and processes in which these ideas have been used. A comprehensive literature survey of the quantitative relationships pertaining to the different configurations is given. The various cell designs are compared on a quantitative basis, usingi lim, and some advantages and disadvantages are discussed.

A study of the performance of subjective probability assessors

Abstract: Despite the key role that subjective probabilities play in decisions made under conditions of uncertainty, little is known about the ability of probability assessors in developing these estimates. A literature survey is followed by a review of results from a continuing series of experiments designed to investigate the external accuracy of subjectively assessed probability distributions. Initial findings confirm that probability assessments provided by untrained assessors are of questionable value in predicting the distribution of actual outcomes of uncertain events. Particular difficulty is encountered when subjects attempt to quantify the extremes of their subjective distributions. The impact of extended assessor training and hypotheses regarding the effects of variation in the assessor's information level and the complexity of the assessment task are explored. Implications for applied decision making are drawn, and directions for future investigations are suggested.

The Influence of State of Stress on Low-Cycle Fatigue of Structural Materials. A Literature Survey and Interpretive Report

Abstract: A literature survey was made on the influence of state of stress on the deformation and fracture behavior during low-cycle fatigue Only the phenomenological aspects of fracture and deformation in the low-cycle range (< 10 5 cycles) are considered Most of the materials investigated are shown or are assumed to have isotropic fatigue properties so that anisotropy was generally not considered For the isotropic case correlation formulas between uniaxial and multiaxial states of stress (strain) are stated in Appendix 1 Individual papers are reviewed to see which formula can best correlate uniaxial and multiaxial data No single criterion was found which consistently correlates the data Of all the correlation formulas the von Mises or distortion energy or octahedral shear stress criterion showed the highest degree of acceptance However, some papers show no good correlation on the basis of this criterion and serious objections are voiced against this criterion on principal grounds- The von Mises criterion gives the same value for two states of stress which differ only by a hydrostatic pressure, it is pressure insensitive Fatigue fracture is shown to be affected by the superposition of a hydrostatic pressure and therefore a preassure sensitive criterion should be used for correlation In future work a clear distinction of the influence of multiaxial states of stress (strain) on crack initiation and crack growth is necessary Crack initiation and propagation studies are urgently needed For isotropic fatigue properties pressure sensitive criteria should be incorporated into the constants of a generalized Coffin-Manson law In the case of anisotropic fatigue properties, new correlation procedures have to be developed

Cyclic creep: an interpretive literature survey

Abstract: An analysis is made of the inelastic deformation of structural materials under cyclic creep conditions such as loading, unloading, reloading, cyclic creep, cyclic relaxation, and low-cycle fatigue with and without hold times under uniaxial and multiaxial states of stress. Constitutive equations such as linear and nonlinear viscoelasticity, plasticity, creep theory and equation of state are examined. It is concluded that an accurate cycle-by-cycle analysis for ratchetting and creep-fatigue interaction is not now possible. For cyclic strain hardening materials, such as stainless steel but not Cr--Mo--V steels, a conservative prediction can be made. 26 figures, 132 references. (DLC)

Decision-making in technologically based organizations: A literature survey of present practice

Abstract: This survey was undertaken to determine what factors are considered when a manager has to decide whether an idea, or new embryo process or product, is to go on to the next stage of development in the innovation process. An attempt was made to provide a complete listing of articles and reports which have been published since 1967. The literature reviewed covers idea generation, transmission and evaluation; market group involvement in the innovation decision process; project selection and evaluation; and possible impact of formal project selection models or techniques on the bench scientist or engineer. The factors or procedures used by various organizations to select and evaluate projects are described. Examples of the several classes of mathematical models proposed by management scientists are given. As was the case in 1967 very few of these models have been used in actual business situations and the reasons for this lack of use are presented.

Interim prediction method for low frequency core engine noise

Abstract: A literature survey on low-frequency core engine noise is presented Possible sources of low frequency internally generated noise in core engines are discussed with emphasis on combustion and component scrubbing noise An interim method is recommended for predicting low frequency core engine noise that is dominant when jet velocities are low Suggestions are made for future research on low frequency core engine noise that will aid in improving the prediction method and help define possible additional internal noise sources

The Structure of Water and Its Solutions

Abstract: The nature of the structure of liquid water has been a matter of scientific interest since before the beginning of this century. Since 1933 the suggestion of Bernal and Fowler [1] that the structure of water is due to the hydrogen bonding between molecules has been the basis of all structural models. In this article we discuss some of the evidence that has been provided by the study of the vibrational spectra of liquid water that bears on the nature of the structure. There has been no attempt to conduct a complete literature survey but rather to select and discuss examples that serve to illustrate the scope of infrared and Raman studies in the study of the structure of water in aqueous solutions.

Investigation of Gust Factors in Tropical Cyclones.

Abstract: : The 1972 Tropical Cyclone Conference requested that FLEWEACEN/JTWC include peak gusts in the warnings when sustained surface wind speeds equal or exceed 50 kts. During 1972, a sustained wind/peak gust graph derived by former JTWC personnel was used. Details on how this graph was derived were not available and there was a general feeling among JTWC forecasters that the gust factors derived from this graph were too high for open water conditions. Therefore, at the 1973 Tropical Cyclone Conference, FLEWEACEN/JTWC requested that all 7th Fleet ships equipped with anemometers include peak gusts as well as sustained winds in their weather reports during strong wind conditions. These ship observations and a comprehensive literature survey led to the derivation of a new sustained wind/peak gust relationship which was introduced into operational use by the JTWC during the 1973 season. This study showed that for strong wind conditions, gust factors (i.e., ratio of peak gusts to one-minute average sustained wind speeds) over open water should fall in the range of 1.20 to 1.25. (Author)

The Morphology of Suspension Polyvinyl Chloride

Abstract: A literature survey is presented on the relationship between the plasticizer absorption capacity and “fish-eyes” content of suspension polyvinyl chloride resin and polymerization conditions (suspending agent, agitation, extent of reaction, etc.) and the resulting resin morphology.

Explosives and pyrotechnic propellants for use in long term deep space missions

Abstract: Explosives and pyrotechnic propellant materials which will withstand heat sterilization cycling at 125 C and ten year deep space aging under 10 to the minus 6th power torr and 66 C have been selected. The selection was accomplished through a detailed literature survey and an analytical evaluation of the physicochemical properties of the materials. The chemical components of the electroexplosive devices used in U.S. missiles and spacecraft were categorized into primary explosives, secondary explosives, and propellant ingredients. Kinetic data on such parameters as thermal decomposition and sublimation were obtained for these materials and used as a basis for the ten year life prediction. From these experimental data and some analytical calculations, a listing of candidate materials for deep space missions was made.

The effect of environmental-loading history on longitudinal strength of glass-fiber reinforced plastics

Abstract: A literature survey and an experimental study are presented on the short term strength variation of G.R.P. specimens subjected to the combined effect of loading and different environmental conditions. Findings are as follows: a) Residual longitudinal strength was found to decrease above a preloading level of about 25–35% of the corresponding reference strength — on exposure to hot (80 °C) water, even after an environmental-loading history (E.L.H.) stage of 48 h. b) No reduction in residual longitudinal strength (R.L.S.) was observed on exposure to cold water (22 °C) and to a dry-hot environment (80 °C).

Crashworthy troop seat investigation

Abstract: : The purpose of this investigation was to perform a research program for the development, analytical verification, mockup evaluation, and comparison of designs for practical crashworthy forward-, aft-, and side-facing troop seating systems for U.S. Army helicopters. Tasks performed during the program included a literature survey, military organization survey, and questionnaire distribution to obtain data on existing seats, restraint systems, accommodation and human factors requirements, mathematical simulation of crash force attenuation, and energy attenuator development. These data were used in developing 19 crashworthy troop seat concepts and several restraint systems applicable to troop use.

A survey and evaluation of remedial measures for earth slope stabilization

Abstract: The results of a literature survey undertaken to identify remedial measures which have been used to stabilize earth slopes are presented. In this review attention is directed to specific case histories and field conditions where the remedial measures were actually used. The remedial measures reviewed include drainage of surface and subsurface water, restraint structures, elimination and avoidance of the slide area, benching and slope flattening as well as a number of special procedures including electro-osmosis, thermal treatment and addition of stabilizing admixtures. Of the procedures reviewed drainage of surface and subsurface water appears to be the most widely and successfully used technique. However, the success of each measure depends to a large degree on the specific soil and groundwater conditions for the slope and the degree to which these are correctly recognized in an investigation and design.

Trends and differentials in age at marriage in Korea.

Abstract: The findings of a study of time trends and demographic social and economic differentials in age at marriage are presented. Korean birth rates declined between 1960 and 1970 and the major cause of this decline was delayed marriage. This article is based on a literature survey and on some analysis of the 1966 Special Demographic Survey. The findings indicated that around 28% of the women born before 1896 were still single at age 18 compared with 50% of the cohort born from 1911 to 1969. Data indicate that both urban and rural areas of Korea have departed from the traditional pattern of early marriage. Especially for females there is competition between marriage and high educational attainment. Also a lower proportion of working women than nonworking women report a lower proportion married before age 20.

An investigation of the effectiveness of existing bridge design methodology in providing adequate structural resistance to seismic disturbances. phase iii: analytical investigations of seismic response of short, single, or multiple-span highway bridges

Abstract: This report is the second in a series to result from the investigation, "An Investigation of the Effectiveness of Existing Bridge Design Methodology in Providing Adequate Structural Resistance to Seismic Disturbances", sponsored by nonlinear analytical procedures are described for Administration. Descriptions are given to the analytical investigations of the seismic response of long, multiple-span, highway bridge structures of the type which suffered heavy damages during the San Fernando earthquake of February 9, 1971. Linear and nonlinear mathematical modeling of this type of bridge structural system is presented. A three-dimensional elasto-plastic flexural column model suitable for modeling the coupled inelastic behavior of reinforced concrete bridge columns is described in detail. A nonlinear mathematical model for simulating the nonlinear discontinuous behavior of bridge expansion joints is also presented. Then, appropriate linear and determining the seismic response of this type of bridge structure. Nonlinear seismic responses are presented for three prototype long, multiple-span, reinforced concrete highway overcrossing structures. Parameter studies carried out on these bridges are described, and the analytical results are presented, discussed, and correlated with the apparent prototype behavior observed during the San Fernando earthquake. Finally, based on the analytical seismic responses presented, general conclusions and recommendations related to the fundamental seismic design methodology of long, multiple-span highway bridges are deduced and summarized. This report is the second in a series. The others in the series are: Phase No.: I, FHWA No.: 73-13, Short Title: Literature Survey, NTIS (PB) No. (if available): (not yet available). /FHWA/

C(10)-methylation of steroidal synthesis intermediate BCD-tricyclic 9-en-5-ones.

Abstract: A literature survey indicated that stereospecific non-reductive β-face methylation at C(10) of steroidal synthesis intermediate BCD-tricyclic 9-en-5-ones had never been effected. An attempt to define the factors controlling the β/α product ratio in such alkylations was made. The course of methylation is significantly affected by the temperature. In the best case, methylation of the sodium enolate of 17 β-t-butoxy-19-(3,5-dimethyl-4-isoxazolyl)-deA-androst-9-en-5-one (18) in tetrahydrofuran at − 78° gave a β/α product ratio of > 5:1. The reaction mixture contained no unalkylated or dialkylated materials, indicating that enolate exchange probably did not occur at this temperature. The 10β-methylated product 23, isolated in 78% yield, was converted to Δ9(ll)-dehydrotestosterone (29). Compounds 23 and 29 are potential intermediates for the synthesis of 11-oxygenated steroids.

A Review of the Toxicology of Colored Chemical Smokes and Colored Smoke Dyes

Abstract: : The report is a review of the inhalation (total-body-exposure) studies performed by this laboratory during 1966 with the M18 series of colored smokes. The acute toxicities of the smokes, the times to death, and the gross signs are compared. A literature survey and toxicological evaluation of the various dyes in the violet, green, and red smoke mixtures are included. Studies necessary for definition of the hazards incident to the use of the dye components in manufacturing and military operations as well as knowledge gaps are described. The dyes used in chemical smokes are: 1- methylaminoanthraquinone; dibenzo (b,def) chrysens-7, 14-dione; 7H-benz (de) anthracene-7-one and 1,4-di-p-toluidinoanthraquinone.

Feasibility Study for Rapid Evaluation of Airfield Pavements.

Abstract: : An investigation was conducted to determine the feasibility of using noncontacting sensor techniques to rapidly evaluate airfield pavements. A literature survey, laboratory test, and field tests were conducted. A broadband video pulse radar system was found to be the most successful. During field tests with this radar system, trenches, pipes, and various soil interfaces were observed and verified. The report described the work done, the video radar system, and a plan for future development of the system to meet pavement evaluation requirements. (Author)

Sources and remedies for restraint system discomfort and inconveniences

Abstract: This study examines possible causes of failure of autombile occupants to wear restraint systems provided by the manufacturers. Attention is directed primarily to confusion, incovenience and discomfort factors in seat belt usage. Study phases consisted of: (a) literature survey to determine state-of-the-art in restraint system design and reasons why people avoid using seat belts; (b) preliminary user survey aimed at identifying in greater detail why people find seat belt systems inconvenient and uncomfortable; (c) new car survey to learn more about how current seat belt systems are designed and installed and if there are new developments that can improve the state-of-the-art; and (d) a series of laboratory studies designed to determine if it is possible to create a more suitable seat belt system. Based on laboratory results an optimized system was designed and tested in two vehicles. These optimized seat belt systems were then compared to four other 1974 vehicle systems to determine their acceptability by users from the standpoints of convenience and comfort. Results showed that the optimized system was significantly favored by test subjects.

Pressure Recovery and Related Properties in Supersonic Diffusers: A Review

Abstract: : This report covers a literature survey on the status of present knowledge on supersonic diffusers. Three types of diffusers are examined: wind tunnel diffusers, ramjet inlets, and supersonic ejectors. No systematic study on wind tunnel diffusers has been found. The results obtained in specific studies, made in conjunction with the design and installation of a number of wind tunnels, show that 100% of normal shock recovery is obtained for M less than 10. Some systematic work exists for ramjet diffusers, with most of the attention being paid to external compression configurations. For supersonic ejectors, comprehensive studies have been made, and useful empirical design methods are available.

Literature Survey on Structural Reliability

Abstract: A brief overview of the structural reliability problem and its relationship to probabilistic and statistical concepts is given. Selected references on structural reliability are compiled from various sources. References address structural reliability and selected topics associated with implementing the structural reliability approach.

Breeding method of hybrid forage sorghum by using male-sterile lines

Abstract: The author has developed a classification of sorghum cultivar groups into four major parental types based on a literature survey of cytogenetical and morphological characteristics and on field studies of varietal performance. The work done by the author in improving the growth rate and yield of sorghum is reviewed and a breeding method which utilizes male sterility is described

Dynamic Properties of Materials. Part 2. Aluminum Alloys

Abstract: : A literature survey on the mechanical properties of aluminum alloys under dynamic loadings has been made The experimental data showing the variation of yield, ultimate strengths and elongation with strain rate and temperature are compiled and tabulated The range of strain rate included in this report is from 000001 in/in/sec to 10,000 in/in/sec, while the temperature range is from -300 deg F to 900 deg F The variations of yield and ultimate strengths are plotted for 6061 and 7075 aluminum alloys It is shown that both the yield and ultimate strengths are higher under dynamic loads than under static loads However, the aluminum alloys are not as strongly affected by strain rate as polymers and steels It is also shown that the yield and ultimate strengths decrease with an increase of temperature

Prestress losses of in-service highway bridge members, A Literature Survey, November 1974

Abstract: The report presents a survey of literature concerning the prestress loss characteristics of in-service bridge members in comparison with those of laboratory specimens. In Chapters 2, 3, and 4 respectively, findings by previous researchers related to camber and deflection, shrinkage and creep, and prestress losses are presented and discussed. Chapter 5 provides a brief summary, and shows the need for further research. The work was done as part of a research project entitled 'Evaluation of Prestress Loss Characteristics of In-Service Bridge Beams.' This project is aimed at establishing a comparison between the behavior of laboratory specimens and that of in-service structural members, and to formulate necessary adjustments to a previously developed procedure for estimating prestress losses in pretensioned bridge members.