Showing papers on "Water environment published in 1979"

Application of Corrosion Fatigue Crack Growth Rate Data to Integrity Analyses of Nuclear Reactor Vessels

Abstract: The methodology of fatigue crack growth analysis in evaluating structural integrity of nuclear components has been well established over the years, even to the point where a recommended practice has been incorporated in Appendix A to Section XI of the ASME Code. The present reference curve for crack growth rates of pressure vessel steels in reactor water environment was developed in 1973, and since that time a great deal of data have become available. The original curve was meant to be a bounding curve, and some recent data have exceeded it, so an important question to address is which reference curve to use for these calculations. The important features of fatigue crack growth behavior in a reactor water environment are reviewed, along with some suggested explanation for the observed environmental enhancement and overall trends. The variables which must be accounted for in any reference crack growth rate curve are delineated and various methods for accomplishing this task are discussed. Improvements to the present reference curve are suggested, and evaluated as to their accuracy relative to the present curve. The impact of the alternative curves is also evaluated through solution of an example problem. A discussion of the conservatisms included inmore » the alternative reference curves as compared with the present reference curve is included. Also research work is identified which could lead to further improvement in the reference curves.« less

Corrosion resistant galvanic coating

Abstract: A coating of the inorganic zinc type which has, among other uses, excellent performance in the cathodic protection of metal from corrosion, especially when exposed to hot water. The coating is composed of mixture of zinc dust, extremely fine, high purity aluminum, sodium aluminum silicate and red iron oxide or titanium dioxide. Clay may be added for flow control and/or thixotrophy. The powder mixture is mixed with an alcoholic solution of partially hydrolyzed ethyl silicate liquid to form a slurry, and the slurry is thereafter sprayed or otherwise applied to a metal substrate to provide a coating having a thickness of 2 to 10 mils. Drying of the coating acts to evaporate the alcohol, and exposure to atmospheric humidity will fully hydrolyze the ethyl silicate to produce a dense, hard, tightly adherent coating which provides excellent corrosion resistance in a hot water environment.

Fatigue Crack Growth of Stainless Steel Piping in a Pressurized Water Reactor Environment

Abstract: Fatigue crack-growth behavior was investigated for types 304 and 316 stainless steel exposed to a pressurized water reactor environment. The effects of test frequency, stress ratio, specimen orientation, heat to heat variables and weld versus base metal performance were evaluated. Crack-growth rates were correlated with the range of crack-tip stress intensity factor, as well as the “effective stress intensity factor” proposed by Walker to account for R ratio effects. Results of the study showed that fatigue crack-growth rates in the water environment were not significantly different from results at the same stress ratio in an air environment at the same temperature. The most important parameter found to affect the crack-growth rate was the stress ratio R , and increasing values of R produced increased crack-growth rates at any given value of stress intensity factor range ΔK . The stress ratio effects were successfully accounted for by employment of the Walker model.

Ground and n–π* excited state structures of the hydrogen bonded complexes pyrazine⋅H2O and pyrazine⋅ (H2O)2

Abstract: Vibronically resolved 1Ag→1B3u(n–π*) excitation and 3B3u(n–π*) →1Ag emission spectra are reported for isolated pyrazine, and the complexes pyraxine⋅Kr, pyrazine⋅H2O, and pyrazine⋅ (H2O)2 in solid neon host at 4.2°K. Distinct zero phonon lines appear in the complex spectra, enabling a separation of vertical and adiabatic excitation with respect to the low frequency intermolecular normal modes. In the monohydrate and bihydrate complexes, the hydrogen bond is only slightly weaker in the n–π* excited states. An upper limit for excited state hydrogen bond lengthening is obtained. The monohydrate 3n–π* complex decays purely radiatively, but a competitive intersystem crossing appears to occur in the bihydrate. The hydrate spectra and lifetimes are unchanged for D2O. Zero phonon lines are just resolved in the spectra of pyrazine isolated in solid ice at 10°K. These data enable a distinction to be drawn between specific solvation due to hydrogen bonding and general solvation due to a polar water environment.

Demosponges as Substrates: an Example from the Pennsylvanian of North America

Abstract: The rigid skeletal frameworks of two heliospongid genera from the Bethany Falls Limestone (Pennsylvanian) of Missouri provided suitable sites of attachment for other marine invertebrates in a quiet water environment. A cluster of three horn corals attached apically to one Heliospongia while it was upright. Other horn corals are in lateral contact with ?Coelocladiella fragments and may have attached to fallen specimens. The distribution of acrothoracic barnacle borings and membraniporiform bryozoans on ?Coelocladiella fragments suggest that the sponges were in an upright position when the epizoans lived. Calcareous worm tubes and shell scars of Derbyia are also associated with ?Coelocladiella. The sponges themselves became established on a soft carbonate mud bottom by growing on productacean shells and possibly fallen blades of calcareous algae. Irregularities in their form indicate that conditions were crowded on limited sites of attachment. The organisms in the assemblage are ecologically coherent and in situ. Ecological requirements of associated organisms and sponge morphologies indicate: (1) the energy of the environment was low to moderate, (2) the rate of deposition was slow and (3) the substrate was a soft carbonate mud.

Viruses in the Water Environment: An Underestimated Problem

Abstract: Most infectious diseases are probably caused by viruses. Viruses are infectious agents that possess either ribonucleic or deoxyribonucleic acid; some viruses also contain lipids and a small fraction of carbohydrates. The nucleic acid is the repository of viral genetic information essential for synthesis and viral replication that occur inside the infected host cell. Viruses are devoid of ribosomes and

Correlations between theoretical and experimental Kerr constants of n-alkyl amides in solution in dioxan and water

Abstract: The theoretical molecular Kerr constants of eleven alkyl amides (related to formamide, acetamide and propionamide), calculated using bond polarisabilities and solution dipole moments, are compared with infinite dilution molecular Kerr constants determined in 1,4-dioxan at 298 K. Kerr effect data are also presented for several alkyl amides in solution in benzene, cyclohexane and water at 298 K. Theoretical molecular Kerr constants were found to be directly proportional to the corresponding experimental molecular Kerr constants measured in 1,4-dioxan. The optical polarisability tensors, associated with carbon–carbon and carbon–nitrogen single bonds and with carbon–hydrogen bonds of the amide alkyl groups, are not significantly changed in going from a dioxan to a water environment.

Fatigue crack growth of A508 steel in high-temperature, pressurized reactor-grade water

Abstract: Fatigue crack growth tests of A508-2 pressure vessel steel have been conducted at two test temperatures (93 degrees C and 288 degrees C) using a variety of constant amplitude waveforms. The load ratios were either 0.1 or 0.125, and the water chemistry was carefully monitored and controlled so as to simulate the nominal pressurized water reactor chemistry. The test procedures are described, and an examination of all the data indicates that the results fall into one of two rather clearly defined categories. One band of data, termed 'low', lies close to or essentially on, the ASME Section XI Code air environment default line. The other band of data, termed 'high', resides approximately midway between the ASME Sec. XI air and water environment default lines. The two bands of data are the result of certain combinations of the waveform and temperature variables listed above, and are determined by the following rules: (1) a ramp time in excess of one second is needed to obtain the high crack growth rate; and (2) the application of a hold time, together with a high temperature, serves to depress a normally high crack growth rate test (i.e. one with a long ramp time) and forcemore » it into the low category. A hydrogen embrittlement model is used as a basis for the explanation of this behavior. During the longer ramp times (approximately one second) hydrogen, formed by aqueous hydrolysis, diffuses into the plastic zone, resulting in local embrittlement.« less

Water Resources Planning and Public Health: 1776-1976

Abstract: Planning for water use and management extends from the earliest cultures of agriculture and water navigation to twentieth century energy development. Within this historical framework, the nature of the relationship of water resources and public health provides an important mirror to the character of human civilization over time. In overview terms, this paper describes man's concern for the water environment from historical and scientific perspectives. Early institutions to manage the public health aspects of water resources; the impact of sanitary engineering on urbanization; and the rise of modern environmental engineering in relation to controlling water pollution are considered. The paper examines a number of specific elements illustrating the substantial impact that public health interests have had on water resources planning in the United States. Beyond usual drinking water supply and pollution control matters, the paper touches upon public safety, insect-borne disease control, institutional change, and issues associated with broad based multipurpose water resource development planning.

Aquatic Plant Management for Recreation Areas

Abstract: : Algae and flowering aquatic plants (submergents, floaters and emergents) form the first link in the food chain, contribute to the water environment by taking in carbon dioxide and releasing oxygen during photosynthesis, provide an animal habitat for the water community, and control erosion. But even with these necessary contributions, certain species have the ability to become major world wide aquatic pest plants. Shallow depth, gently sloping shorelines, stable bottoms, warm water, clear water, and water of high fertility are environmental factors that contribute to dense aquatic plant growth. Nitrogen and phosphorus compounds discharged from sewage plant effluents, home waste disposal systems, food-producing plants, and well-fertilized agricultural watersheds increase fertility thereby stimulating profuse growth of algae and aquatic plants. Also, seed production, vegetative reproduction and winter buds intensify the problem. Excessive growths interfere with swimming, boating and fish propagation; clog intake pipes; make water unfit to drink without treatment; cause oxygen depletion and subsequent fish kills due to increased respiration and decomposition; and speed up the natural lake filling processes. (Author)

The role of applied climatological research in alleviating the hazardous impact of the monsoons in South and Southeast Asia

Abstract: This paper surveys the extent to which the Asian Monsoon system and, especially, its hazard component have been studied from the applied climatological standpoint and seeks to draw attention to the deficiencies and inadequacies. More intensive and detailed investigations are required for providing a better basis for planning, implementing and evaluating preventive and remedial action in hazard mitigation. The main focus of the discussion is the instability of the hydro-climate which constitutes the bane of Asian agricultural economies. It is felt that the main thrust of applied climatological inquires should be directed towards instilling in decision-makers, planners, and the farming community in general, a better knowledge, understanding, and appreciation of the opportunities and challenges of the water environment as an economic constraint. In this connection, more emphasis should be placed on the manageable aspects of the atmosphere/man interaction directly or indirectly contributing towards greater hazard proneness. The role that applied climatology proposes to play should be guided more by physical-environmental and socio-economic realities rather than by mere academic dictates. Also, the need for an inter-disciplinary approach to studying the adversities of the monsoon climate cannot be over-emphasized.

Imaging optical probe for pressurized steam-water environment

Abstract: An air-cooled imaging optical probe, with an outside diameter of 25.4 mm, has been developed to provide high resolution viewing of flow regimes in a steam-water environment at 343/sup 0/C and 15.2 MPa. The design study considered a 3-m length probe. A 0.3-m length probe prototype was fabricated and tested. The optical probe consists of a 3.5-mm diameter optics train surrounded by two coaxial coolant flow channels and two coaxial insulating dead air spaces. With air flowing through the probe at 5.7 g/s, thermal analysis shows that no part of the optics train will exceed 93/sup 0/C when a 3-m length probe is immersed in a 343/sup 0/C environment. Computer stress analysis plus actual tests show that the probe can operate successfully with conservative safety factors. The imaging optical probe was tested five times in the design environment at the semiscale facility at the INEL. Two-phase flow regimes in the high temperature, high pressure, steam-water blowdown and reflood experiments were recorded on video tape for the first time with the imaging optical probe.

Holoceńska fauna mięczaków i martwica wapienna z Głowiny koło Dobrzynia nad Wisłą

Abstract: Opisano holocenskie osady zboczowe przesycone w roznym stopniu weglanem wapnia wystepującym czesto w postaci martwicy wapiennej. W osadach wykryto 17 gatunkow mieczakow, glownie ślimakow lądowych. Odtworzono warunki powstania osadow z fauną. HOLOCENE MOLLUSCAN FAUNA AND CALCAREOUS SINTER FROM GŁOWINA NEAR DOBRZYŃ ON VISTULA The molluscan locality is situated at slope foot east of Dobrzyn on Vistula (Fig. 1). The slope was shaped by Early Holocene river erosion and landslide-deluvial movements. Its lower part is formed of glacitectonically disturbed Pliocene clays overlain by two till horizons separated here by fluvioglacial sands. The slope is about 40.0 m high (Figs. 2, 3). The slope is covered with deposits among which there may be differentiated: - deposits related to surficial creep and slopewash processes, with well marked stratification (silts, sands, gravels and boulders); - deposits formed by landslides operating to greater depths, comprising large packets of Pliocene clays and cut by numerous dislocation planes usually dipping towards the slope. The deposits are impregnated with calcium carbonate which forms typical calcareous sinter in some places. Gastropod and bivalve shells are nonuniformly distributed throughout the deposits, being common in deluvial ones and scarcer in the colluvial. Terrestial gastropods predominate among 17 molluscan species recorded at Glowina (Table 1). Aquatic molluscans are represented by four species only: Bithynia tentaculata (L.), Planorbis planorbis (L.), Viviparus fasciatus (M u I l.), and bivalves of the genus Unio . The faunal assemblage appears fairly inhomogeneous from the ecological point of view. It comprises representatives of 8 out of 10 ecological groups differentiated by V. Ložek (1964), that is the species confined to forests only ( Cochlodina laminata ), those living in forests and open space ( Arianta arbustorum , Bradybaena fruticum , Cepaea hortensis , Helix pomatia ), wet forests ( Perforatella bidentata ), steppes ( Chondrula tridens ), open spaces ( Euomphalia strigella ), wet ( Laciniaria plicata ) and wet and swampy places ( Monachoides rubiginosa , Succinea putris ), and the above listed aquatic species living in overgrown stagnant water ( Planorbis planorbis ), flowing water ( Viviparus fasciatus , Unio sp.) or stagnant and flowing water environment ( Bithynia tentaculata ). The requirements of Recent representatives of this fauna! assemblage suggest thermal conditions similar to the present. The age of the molluscan assemblage is primarily indicated by the species Helix pomatia, the expansion of which has mainly taken place in the historical times. This suggests Late Holocene age of the assemblage. The processes operating on the slope were mainly related to imperviousness of Pleistocene clays and their susceptibility to mass movements, as well as effluent seepage of water out of Quaternary deposits. Southward exposition of the slope and humidity of ground were favourable for the development of vegetational cover and molluscan fauna and the formation of calcareous sinter.

Experimental vibration study of in-air and fluid coupled co-axial cylinders

Abstract: It was the objective of this study to develop and carry out an experimental program which would provide additional insight into the mechanics of fluid--solid interaction with respect to the response of a set of coaxial cylinders with water in the annulus. Such configurations are found in nuclear reactors in the vessel wall-thermal liner. The effects of cylinder thickness and the fluid filled annulus gap size on the resonant frequencies and mode shapes of the cylinders (either singly or coupled in air and a water environment) are presented in this paper; also included is an evaluation of damping for selected gaps and cylinder thicknesses. Details of the experimental setup and procedures are also outlined.