Showing papers on "Literature survey published in 1976"

Probability-based short term design of soil slopes

Abstract: Earth slopes are generally designed in an environment characterized by numerous uncertainties, stemming from limited sampling efforts on soil strata with variable soil properties, amplified further by the discrepancy between in situ and laboratory measured soil strengths. Additional uncertainties are also introduced from various simplifying assumptions and idealizations that are necessary for a practical mathematical analysis of stability.The uncertainties involved in the short-term stability of soil slopes have been evaluated from an extensive literature survey. A procedure for developing design of earth slopes based on a permissible risk is formulated whereby experience, published research results, experimental test data and judgement can be consistently incorporated in the evaluation of uncertainties and reliability of a given design. An example of slope design is presented to illustrate the proposed risk-based design method.

Hydrodynamics of groundwater flow in a fractured formation

Abstract: Hydrodynamical aspects of groundwater flow in fractured formations and the basic hydraulic properties controlling the flow are the subject of the present consideration. A brief literature survey on studying the physical characteristics of the fractured rocks and on developing an understanding of the mechanism of fluid flow in fractured formations constitutes an introductory section. Basic definitions, relations, and assumptions given for subsequent interpretation of the flow behavior in a fissured rock then follow. Concepts of fractured, homogeneous, and heterogeneous water-bearing formations and their response mechanism to a pressure change are considered. The general differential equations for a flow in a fractured and in a heterogeneous formation of uniform anisotropy are derived. Two types of the flow behavior, fissure flow and pore flow, are distinguished. Two drawdown equations, respectively, for a flow in a fissure space, whether void or infilled with a fine material, and for a flow in a porous space to a well discharging at a constant rate in a fractured aquifer, are given. A fractured reservoir response to a pressure change due to pumping is illustrated by the field drawdown and recovery data. A particular case of a heterogeneous formation, an aquifer-aquitard system, is discussed, and the drawdown distribution in both aquifer and aquitard is given when account is taken of their elastic properties.

Quantitative electron microscopy of nucleic acids

Abstract: This Chapter is not intended to be a comprehensive literature survey, but rather an introduction to techniques that are now available for preparing nucleic acid samples for electron microscopy. In particular, an effort has been made to emphasize a quantitative approach to the electron microscopy of nucleic acids and to give examples of quantitative applications of the techniques discussed. We have often used examples from our own research to demonstrate ways in which quantitative electron microscopy can be done; however, this does not imply that these are the only examples available. Younghusband and Inman (1974) published a review of the electron microscopy of DNA that contains extensive literature references, and Chow et al. (1975) prepared a laboratory manual for the electron microscopy of nucleic acids containing extensive information about techniques, instruments, and supplies.

The epidemiological situation of brucellosis in africa

Abstract: Brucellosis, as a geomedical literature survey has shown, is spread to a higher of lesser degree of incidence virtually over the whole African continent. Its epidemiological spectrum of host animals is especially rich amongst the domestic and wild animal species. All domestic animal species and 21 of 26 herbivorous and 5 of 12 carnivorous wild animal species screened yielded positive brucella antibody serotitres. Thus self-maintaining natural foci independent of the domestic stock have firmly been established. The mapping of the epidemiological situation must be based on survey data which should have been planned, exactly performed, analyzed and reported according to statistical rules. Unfortunately Africa is especially badly covered in the world literature in the field of brucellosis. Representing itself 32.0% (49/153) of the countries of the world, their Medical and Veterinary Departments contributed only 2.1% of the computerized world literature on brucellosis in the period 1969-74. This picture can be considerably changed by including the non-computerized "grey literature" of Department and Laboratory Annual Reports into the screening process. By introducing objective, mathematical criteria for determining the degree of incidence from the available data, the following results were obtained from the literature survey: brucellosis is known or suspected to exist in 40 of the 49 African countries (82%). In 20 (41%) of these countries it represents a major problem, in 10 (20.4%) a moderate problem in the other 10 countries a minor problem to human health and economy. Following the rule that brucellosis can be expected to exist everywhere in the world (with the exception of a few islands) where cattle, sheep and/or goats are kept unless it has been eliminated by vigourous measures of control, it may be expected that the remaining 9 African countries not yet reporting also harbour this chronic, zoonotic disease. 35 of the 40 countries reporting have found brucellosis regularly, 1 exceptionally among domestic animals, 5 among game animals. Only 17 of these 35 (48.5%) have scheduled the disease, even if its incidence has been reported to be high. Only 32 of the 49 countries report on human brucellosis. The main reservoirs of disease and risks of infection vary from place to place with the different main kinds of domestic stock, the animal husbandry and human consumption methods and habits. Thus mainly the cattle herds are the source of infection for those countries where large numbers of cattle are kept and the drinking of raw milk is the custom; however, there is no strict correlation between these two factors. Goats and sheep fill the epidemiological place in all those countries where the lack of marketable milk curtails its consumption; the small ruminants are kept as the main source of meat supply and in close contact with the farmers family within the compound or house.

Harmonic Generation for Measurement of Internal Stresses as Produced by Dislocations

Abstract: Absrmcr-The present knowledge on the state of microscopic internal stresses, as produced by dislocations, and the relation of these internal stresses to materials properties such as flow stress and the state of fatigue are briefly reviewed. It will then be shown that ultrasonic harmonic generation is sensitive to the dislocation density and loop lengths and thus to microscopic internal stresses Some experimental data on harmonic generation in a deformed and fatigued aluminum specimen, which are in agreement with the above theory, are presented. Thus the technique of ultrasonic harmonic generation is shown to be a new and potentially powerful technique for the nondestructive evalua- tion of technologically important materials. N A RECENT meeting on nondestructive evaluation of internal stresses (l) the need for additional work in this area became quite apparent. The presence of either a compres- sional or a tensile macroscopic internal stress in a structural component is a very important parameter, in particular in de- sign work, which very effectively determines crack initiation and crack propagation under external loads. Strong efforts are being made at present to determine this kind of internal stress, mainly using X-ray techniques and, lately, acoustic birefringence and magnetic techniques. The role of micro- scopic internal stresses on mechanical properties, on the other hand, seems to be not quite clear to the designer or mainte- nance. The present paper, therefore, is addressed specifically to this subject. In particular, the internal stresses due to dis- locations which are the defects responsible for plasticity ef- fects in metals will be discussed. A literature survey as well as some preliminary experiments to be reported in this paper seem to indicate that the flow stress as well as a part of the fatigue life of a material are reflections of the state of the microscopic internal stress. These experiments have been per- formed using acoustic harmonic generation, and it is this tech- nique that is proposed in the present paper as a possible non- destructive tool to study the microscopic internal stress due to dislocation or, in other words, plasticity effects. The work reported here by no means is complete, and many basic questions remain to be answered. It is hoped, however, that the present work will lead to a better understanding of the materials' reliability and product lifetime.

Evaluation of the Effectiveness of Training Devices: Literature Review and Preliminary Model

Abstract: : The present report describes a program of research whose goal is the development and eventual validation of a method for predicting training device effectiveness. As the lead publication in the series, this report presents a preliminary model for the prediction of one of the most important aspects of training effectiveness--transfer of training. In developing the preliminary model, every attempt has been made to examine and, if possible, to build upon previous efforts. Toward this end, several different kinds of literature potentially bearing on the prediction of device effectiveness have been exhaustively reviewed, reduced, and analyzed. Previous methods and models dealing with the design or evaluation of training programs were examined. General theories of transfer were studied as were the specific constructs believed to mediate transfer. Finally, a host of substantive issues were examined, particularly in terms of empirical data on specific variables and their impact on transfer. The report describes and discusses this information and, when appropriate, indicates its incorporation into the model. In the following four sections of the report the results of the literature survey are described together with implications for a preliminary model for use in predicting training effectiveness.

High voltage design guide for airborne equipment

Abstract: : The report supplies the theoretical background and design techniques needed by an engineer who is designing electrical insulation for high-voltage high-power components, equipment, and systems on aircraft A literature survey and abundant bibliography identify references that provide further data on the subjects of partial discharges, corona, field theory and plotting, voids and processes for applying insulation Both gaseous and solid insulations are treated Cryogenic and liquid design notes are included Tests and test equipment for high voltage insulation and equipment are defined Requirements of test plans and procedures for high-voltage high-power equipment are identified and illustrated by examples Suggestions for high-voltage specifications are provided Very few of the Military and Government specifications deal with system voltages above 10kv, thus most aircraft high- voltage specifications will have to be derived from the power industry specifications and standards produced by ASTM, IEEE, and NEMA

A Study of Tensile Stresses in a Journal-Bearing Oil Film

Abstract: Tensile stresses of 740 kN/m2 have been observed in the oil film of a steadily loaded journal bearing. A critical eccentricity ratio has been suggested below which, for a particular clearance, a tensile stress may be generated.An extensive literature survey indicates the sensitivity of the liquid's tensile strength to such factors as gas content, viscosity, particle content and the surface finish at the liquid/bearing material interface.It is suggested that previously attempted observations of liquid tensile stresses in journal bearings may have been limited by the configuration of the pressure-measuring device.The possibility of bearing Babbitt damage arising from transient and steady-state liquid tensile stresses is postulated.

Basic chromosomal proteins in lower eukaryotes: relevance to the evolution and function of histones.

Abstract: The occurrence of basic chromosomal proteins in lower eukaryotes provides a useful approach to the study of histone evolution and function in higher eukaryotes. The histones of higher plants and animals are very similar and some are nearly identical, suggesting a high degree of evolutionary conservation within this group of proteins. However, a literature survey reveals that in the lower eukaryotes the histone situation is quite variable. The ciliates, and the true and cellular slime molds possess basic chromosomal proteins that are very similar to the histones of higher plants and animals. Various other lower eukaryotes possess basic chromosomal proteins that resemble at least some of the major histone fractions, and some microorganisms possess basic chromosomal proteins that bear little or no relationship to higher plant and animal histones. Since histones play a major role in the control of gene expression and the maintenance of chromosome structure in higher organisms, the evolution of these proteins represents a major change in the packaging of DNA and the mode of regulating gene expression in eukaryotes.

A guide to the use of grass in hydraulic engineering practice

Abstract: Guidance on the use of grass to stabilise surfaces subject to erosion by intermittent flow. Provides information on the erosion resistance and frictional resistance of grass. Includes recommendations on grass mixtures, etc. Extensive literature survey

Reproduction, Growth, and Development in the Yucatan Deer Mouse, Peromyscus yucatanicus

Abstract: Measures of reproduction, growth, and development were monitored in a laboratory population of the neotropical Yucat n deer mouse, Peromyscus yucatanicus , over an 18-month period. Supplementary data on reproduction were obtained from field studies, a literature survey, and museum specimens. In addition to the yucatanicus studies, information on embryo counts was obtained from the literature and from museum specimens for other species in the mexicanus species-group of Peromyscus . The reproductive pattern of yucatanicus differs from that of species of Peromyscus with a generally northern distribution in length of breeding season, which is thought to be year-round in yucatanicus , and in the gestation period of non-lactating females, longest yet reported for a species of Peromyscus . All other aspects of reproduction studied were similar to those of various northern species. Rates of growth and development were slower than those reported for most northern species; in many respects, rates for yucatanicus were remarkably similar to those of the pinon mouse, P. truei . There was a strong negative feedback of large litters on rates of growth and development in yucatanicus , suggesting a long history of close regulation of litter size to approximately three offspring. The pattern of reproduction, growth, and development in this species is examined in light of the ecology of this species, apparently unique in the mexicanus species-group.

Transversal Filter Design and Application in Satellite Communications

Abstract: A brief literature survey of transversal filters is followed by a design example of a binary transversal filter. A particular application in the modulator of the single channel per carrier data transmission equipment is described. Computer simulations and COS/MOS hardware implementation proved the validity and the feasibility of the theory described by Mueller. Design and evaluation of a linear phase filter approaching the Nyquist channel is the end result of our study.

Behavioral Issues in the use of interactive systems

Abstract: This paper identifies behavioral issues related to the use of interactive computers primarily by persons who are not computer professionals, so-called ‚general users.‘ This is not an exhaustive literature survey but instead provides: (1) a structure for discussing issues of interactive computing, and (2) the authors' best estimate of important behavioral problems, with suggestions for solutions.

Questionnaire Construction Manual. Annex: Literature Survey and Bibliography.

Abstract: : A literature survey on questionnaire construction encompassed journals, books, and reports in psychology, sociology, education, and marketing, and documentation published by the Defense Department The search yielded over 2,000 references, which are listed in the 279-page annotated bibliography A synthesis of the findings is based on abstracts selected for their relevance from the references Results of the search were the basis for developing a manual on questionnaire construction designed for Army personnel responsible for field evaluations

Chronic oil contamination and aquatic organisms with emphasis on diptera: status and bibliography

Abstract: The author's literature survey reveals that only recently have small and/or continuous low-level contaminations by petroleum and petroleum products begun to receive the attention previously accorded large marine spills. Very little is known about the long-term biological effects of this kind of contamination upon marine organisms and almost nothing with regard to freshwater organisms, particularly concerning the individual organism. He recommends that the lack of literature and current research on the subject receive priority attention and offers a bibliography intended to facilitate efficient planning for future investigations. (RFC)

Solid state hydrogen storage materials for application to energy needs. Final technical report, 1 Oct 1973--31 Mar 1976

Abstract: Six areas of study of solid state hydrogen storage materials were completed in the two and one half year study. These were (1) literature survey and field trips relating to studies of hydrogen storage materials, (2) safety characteristics of LaNi/sub 5/ hydrides, (3) general hydriding characteristics of LaNi/sub 5/, (4) study of kinetics of hydrogen desorption of LaNi/sub 5/, (5) studies of new alloy systems, and (6) development of fundamental insights of hydriding and of predictive criteria for new and improved hydrides. The safety characteristics of LaNi/sub 5/ were fully evaluated in terms of the properties of powders. Bulk powder properties determined were: ignition temperature, relative combustibility, flammability, shock sensitivity, impact sensitivity, spark sensitivity, and explosibility. Studies of dispersed dust clouds were conducted in which ignition temperature, minimum ignition energy, minimum explosive concentration, maximum explosive pressure, and maximum rate of pressure rise were determined. From these data, an index of explosibility was obtained, which indicated a 'weak' rating. The general hydriding characteristics included data on activation, effects of repetitive cycling, hysteresis effects, surface poisoning effects, and more precise pressure-temperature-composition relationships of the system than have been available in the literature. The kinetics of hydrogen desorption from LaNi/sub 5/ hydride weremore » established. The order, rate constant, and activation energy were determined. The effects of surface contamination were studed by exposure to air, oxygen, and moisture. Evaluation was conducte principally by the change in the kinetics of desorption of hydrogen. (GRA)« less

Iron and nickel carbonyl formation in steel pipes and its prevention: literature survey

Abstract: Data were compiled on the stability and formation rates of iron and nickel carbonyls. The data demonstrate that carbonyl formation in steel pipes is governed largely by kinetics. The rate of carbonyl formation is a function of several factors: temperature, pressure, gas flow rate, gas composition, impurities in the gas, alloy composition, surface conditions, and pretreatment of the surfaces. An evaluation of techniques for detecting iron and nickel carbonyls in gases showed atomic absorption spectroscopy to be a highly effective (approximately 1 ppB), almost instantaneous analytical technique. Carbonyl formation in pipe steels seems to be prevented mainly by the use of steels with high chromium contents, by lining the tubing with copper, or by use of any stable coating that prevents the carbon monoxide from directly contacting the metal. 23 references

The subunit structure of glycolytic enzymes.

Abstract: 1. 1. The subunit molecular weight of enolase from coho salmon has been determined by sedimentation equilibrium in dissociating solvent systems and by acrylamide gel electrophoresis in sodium dodecyl sulfate. 2. 2. The enzyme which has a native molecular weight of 93,000 dissociates into subunits with mol. wt of 45,000–50,000, and thus shows properties characteristic of most of the other enolases studied. 3. 3. A literature survey of the subunit structure of glycolytic enzymes in different species was consequently carried out, and the data are tabulated. 4. 4. With the exception of phosphoglycerate kinase, all the enzymes in the glycolytic pathway appear to be dimers or higher polymers of mostly identical subunits. 5. 5. The fact that these subunit structures have been preserved through evolution suggests that they impart some important biological functional advantage to the living cell.

The growth and activity of wheat root systems

Abstract: A knowledge of root growth and the activity of separate members of the root system is necessary before a comprehensive understanding of plant water and nutrient uptake is possible. The literature describing the developmental characteristics of wheat root systems is first reviewed. Methods of examining root systems in the field are compared, and studies of the contribution of seminal and nodal roots, and the effects of soil environment are discussed. Finally, nutrient and water uptake are considered mainly from the literature concerned with soil processes supplying nutrients to the root surface. The literature survey highlights the scarcity of field studies of water and nutrient uptake compared to laboratory studies and the poor understanding of the ways in which soil water status affects root growth and activity. An experiment in which spring wheat was grown in soil columns in a controlled environment is reported. Water was withheld during growth and the consequences for root growth and nutrient and water uptake followed. Nodal root growth was also restricted but this treatment was largely inconclusive because of the limited time during which conditions comparable to those in the field could be maintained. It was decided from these experiments to work with a field crop; a major study of the micro-climate and growth of winter wheat was in progress, so it was appropriate to examine in detail the growth and functioning of the crop's root system. A number of experiments were set up but this thesis mainly describes the root growth, and associated nutrient and water uptake of the normal field-grown crop. Measurements of root dry weight and length, plant nutrient content and water use are reported in early sections, with subsequent calculations of nutrient and water inflow; the possible contribution of mass-flow to plant nutrient is considered. A pattern of nutrient inflow not previously reported was found and possible explanations are discussed. The influence of soil properties, root distribution and atmospheric conditions on water inflow are also examined. The work shows the importance of field studies in understanding root growth and activity, and puts forward a number of suggestions for future progress.

Review of corrosion experience with copper-nickel alloys in sea water piping systems

Abstract: A literature survey of prior information on sea water attack on Cu-Ni piping shows that incidence of attack is a function of exposure to polluted water containing sulphides, a condition that occurs at many fitting-out basins. Deposition of copper sulphide on Cu-Ni surfaces is cited as the probable cause of pitting because the sulphide layer is cathodic to the base metal. Stagnation of sulphide-contaminated water accelerates attack. Other deposits such as carbonaceous films formed from residual drawing compounds during tube manufacture, oxides formed during brazing operations and solids settling out from water at excessively low velocities amy also give rise to pitting corrosion.

Convex chutes in converging supercritical flow

Abstract: : This study contains a brief literature survey and limited experimental data regarding the water-surface contours for supercritical flow in a steep converging chute. Items relevant to design of the chute sidewalls are described, and the development of a computer model for chute design is suggested. The author also suggests that a horizontal transverse water surface cannot be obtained unless parallel sidewalls are used and that for a converging chute, the designer will probably have to evaluate and accept some level of nonuniformity in the flow. (Author)

A literature survey of the potentially adverse effects of the drugs commonly prescribed for the elderly.

Abstract: Part I: Hard data concerning adverse drug reactions are notoriously difficult to obtain Some of the problems arise because of: --patient variables including age, sex, genetic differences, and current illness --multiple drug use, continuation of smoking, and use of alcohol --variations in dose, duration of treatment, and route of administration --some effects are not reported but many reported effects are not truly due to the drug indicated Nevertheless, we need to be aware of potential adverse reactions Our ability to recognize drug side effects will be improved if we have some idea which kinds of reaction may occur Part I deals with the analgesics, sedatives, laxatives, antacids, antidiabetic agents, antihypertensives and cardiovascular drugs Potential systemic and ocular adverse reactions are listed

Feasibility of Transplantation, Revegetation, and Restoration of Eelgrass in San Diego Bay, California.

Abstract: : The study was conducted to evaluate the feasibility of several methods of eelgrass (Zostera marine L.) transplantation, restoration, and revegetation in San Diego Bay, California. A literature survey was conducted and current state-of-the-art eelgrass transplant methodologies are presented. Two transplant methods are recommended; however, since neither of these has been tested in a large-scale field program, a preliminary pilot transplant study is also recommended. Transplantation costs for each method have been estimated and are also presented.