Showing papers on "Water environment published in 1988"

Nutrient regeneration in cold, high salinity bottom water of the Arctic shelves

Abstract: Nutrient regeneration in cold, high salinity bottom water has been studied in Storfjorden, southern Svalbard. This bottom water was a mixture of Atlantic water with brine produced by sea ice during its formation and aging. The concentrations of nutrients, oxygen and total carbonate in this high salinity water are used to estimate the decay rates of organic matter at the sediment-water interface in a cold water environment. The relative regeneration rates of the constituents from the soft parts of organic matter are found to be in good agreement with the literature values. Silicate from the hard parts is concluded to have a higher rate of regeneration relative to the other nutrients in cold water than in warm water. The regeneration rates are used to estimate the time required for the production of the organic decay components contributing to the nutrient maximum in the upper halocline of the Canada Basin in the Arctic Ocean, in order to estimate the residence time of this water. The estimated residence times given by the different components are approximately 10 years.

Lower Devonian Gastropod Biogeography of the Western Hemisphere

Abstract: Early Devonian biogeography has been based primarily on articulate brachiopods, rugose corals and trilobites. Study of gastropod literature and unpublished collections confirms previously utilized biogeographic units based on other taxa: the Eastern Americas Realm; the Malvinokaffric Realm; and the Old World Realm. Spiny platyceratids, Strophostylus and Crossoceras are restricted to the Eastern Americas Realm which can be informally divided into three paleoclimatic regimes: Hudson Bay Platform — Michigan Basin (tropical to subtropical with abundant evaporites and oolites), Appalachian Basin (subtropical to warm temperate), and the Amazon-Colombian area (moderate to cool temperate with limited to no carbonates). Overall gastropod taxic diversity is highest in Old World Realm faunas, which include more highly ornamented forms such as the oriostomataceans and salpingostomatids, and the genera Kodymites and Euomphalopterus found in Arctic and western North America (Alaska, British Columbia, Yukon and Northwest Territories), Bohemia, and southeastern Australia. Nevada gastropods confirm the shifting biogeographic boundaries recognized previously by other faunal groups. In Lochkovian time this area was part of the Old World Realm. During Pragian-early Emsian time Nevada contained typical Appalachian gastropod genera (Nevadan Subprovince of Eastern Americas Realm). Later in the Emsian (Eurekaspirifer pinyonensis Zone) mixing occurred with elements of both realms co-occurring. By Eifelian time the gastropods were wholly of Old World Realm character. The Malvinokaffric Realm fauna of southern and central South America, Falkland Islands and Antarctica is strongly depauperate, with only four superfamilies represented from the seventeen then extant. Characteristic genera are Plectonotus (Plectonotus) and large species of Tropidodiscus. The reduction in taxonomic diversity from the Old World Realm to the Eastern Americas Realm to the Malvinokaffric Realm is consistent with an interpreted change from warm tropical to warm temperate to the cooler water environment of high paleolatitudes of the southern hemisphere. The distribution of Old World Realm faunas, as well as calcareous algae and oolites favor paleogeographic reconstructions with the Early Devonian equator passing through Alaska and the Canadian Arctic Islands.

The influence of a dam having no fishway on the distribution of decapod crustaceans in the Yukinoura river, Nagasaki, Japan

Abstract: Samplings of decapod crustaceans were conducted in the Yukinoura River to estimate the influence of a dam having no fishway on the distribution of these animals. Eight decapods were collected from freshwater area. Two of them, Geothelphusa dehaani and Neocaridina denticulata, were landlocked species, and the others were amphidromous or catadromous species. The present fauna can not be compared directly with the fauna before the dam construction because of the absence of comparable studies. Comparing the species composition from respective sampling stations, however, the influence of the dam on their distributions can be estimated as follows: (1) Caridina typus, Macrobrachium japonicum and Macrobrachium formosense could no longer get by the dam into their former habitats. (2) Eriocheir japonicus could reach the dam lake but stopped migrating upstream into its former habitat. (3) Caridina leucosticta had the upper part of its former habitat destroyed by the dam and dam lake. (4) N. denticulata had an expansion of distribution because of the still water environment in the dam lake. (5) G. dehaani was unaffected by the dam. At first glance, Caridina japonica, a resident in the uppermost stream, can be categorized in the fifth category, but its population density seems to have decreased after the completion of dam in 1976.

Benthic Communities in the South African Devonian

Abstract: The Lower Devonian clastic Bokkeveld Group of South Africa likely resulted from the vertical stacking of a number of wave dominated deltaic complexes. Concentrating on the lowermost of these deltaic cycles, comprising the Gydo and Gamka formations, it is possible to recognize a number of benthic invertebrate fossil communities. These can be correlated with the various depositional sub-environments within a delta complex. The deepest water environment was the prodelta-shelf area in which shale was deposited. This area was home to the most diverse fossil assemblage, dominated by thin-shelled, free lying brachiopods but which also contained infaunal bivalves, gastropods, trilobites, crinoids and hyoliths. Higher in the sequence the sediment becomes coarser grained and sandstone becomes interbedded with siltstone. In this delta slope environment thicker shelled brachiopods predominate and trilobites become progressively scarce. At the top of the deltaic pile shallow water depositional environments were developed, including distributary mouth bars and tidal flats. In such areas low diversity communities existed. Distributary mouth bars were dominated by large thick-shelled brachiopods fixed to the substrate by functional pedicles; tidal flats were dominated by infaunal bivalves and inarticulate brachiopods. Similar benthic assemblages to those detailed for the lowest deltaic cycle can be found in some of the overlying cycles but the topmost part of the Bokkeveld Group is apparently devoid of invertebrate remains. However, in the basal part of the overlying Witteberg Group a few representatives of the shallow water communities have been found.

Stress corrosion cracking resistance of alloys 600 and 690 and compatible weld metals in BWRs: Final report

Abstract: The relative susceptibilities of alloy 600 and 690 base metals and I-82, I-182, R-127 and R-135 weld metals to intergranular stress corrosion cracking (IGSCC) in either pure water or a simulated resin intrusion environment at 288/degree/C were evaluated. Alloy 600, I-182, and I-82 weld metals were susceptible to various degrees of IGSCC in oxygen containing pure water when creviced, and immune to IGSCC when uncreviced. Alloy 690 was immune to IGSCC under all pure water conditions. Alloy 500, alloy 690, I-182, and I-82 were all susceptible to cracking in the simulated resin intrusion environment, although alloy 690 exhibited the greatest resistance to SCC. The high chromium experimental weld alloy were immune to cracking under all conditions examined. The IGSCC susceptibility of seven different weld metals used to weld alloy 600 and A508 were also evaluated in the resin intrusion environment at 288/degree/C. Weldments made with I-625, I-182, and I-82 (GTAW) were the most susceptible, whereas welds made with I-132 were the least susceptible. Most of the weldments failed at the fusion line between the weld metal and the A508 steel, and the SCC susceptibility increased with increasing hardness measured at the fusion line. There was no effect of crevice conditionmore » or heat treatment on SCC susceptibility. The SCC susceptibility of Type 316 NG stainless steel welded with R-127, R-135, I-72 and Type 308L weld metals was evaluated in pure water and resin intrusion environments at 288/degree/C. All of the materials were immune to SCC in the pure water environment. In the resin intrusion environment, both the I-72 and R-135 weld metals were immune to SACC, but the R-127 and Type 308L weld metals exhibited SCC. The Type 316 NG stainless steel was susceptible to transgranular SCC in the resin intrusion environment, except when welded with I-72, in which case it was immune. 36 refs., 4 tabs.« less

Chromium steel excellent in corrosion resistance

Abstract: PURPOSE: To manufacture a chromium steel excellent in corrosion resistance and formability by incorporating specified percentages of C, Mn, Si, P, S, Cr, Cu, Ni, Ti, N and Al to Fe. CONSTITUTION: A chromium steel which has a composition consisting of, by weight, ≤0.01% C, ≤0.5% Mn, ≤0.6% Si, ≤0.01% P, ≤0.005% S, 3-12% Cr, 0.3-0.8% Cu, 0.3-0.8% Ni, 0.1-0.3% Ti, ≤0.003% N, 0.2-0.5% Al, and the balance Fe with inevitable impurities and further containing, if necessary, 0.01-0.3% of one or ≥2 elements among Zr, V, and Nb is prepared. By this method, the chromium steel showing excellent corrosion resistance in a highly corrosive exhaust gas condensation water environment and having superior formability can be obtained. This chromium steel is useful, e.g., as a stock for automobile exhaust gas system equipment. COPYRIGHT: (C)1990,JPO&Japio

The influence of oxidation‐reduction potential on the water environment of Aswan high dam reservoir

Abstract: This study was undertaken to clarify in detail the dynamics of oxidation‐reduction potential in the seasonally oxic and anoxic conditions of Lake Nasser. The profile of dissolved oxygen and redox potential was determined. The dynamic mechanisms of deposition and dissolution of some chemical elements through the water‐sediment interface were studied.

Amphiphilic properties of angiotensin and its fragments

Abstract: Many biologically active peptides are supposed to interact with specific receptors mainly due to hydrophobic forces. In order to obtain a more detailed information about the peptide molecule behavior at the "water-non-polar-phase" boundary an approach to the calculation of stable conformations on such a boundary has been developed. This approach is used for investigation of the amphiphilic properties of angiotensin and its six fragments. The results of calculations of transfer energies of these peptides from the water environment to the phase boundary are in agreement with the experimental data.

Electrochemical corrosion-scoping experiments: An evaluation of the results

Abstract: Prior to emplacement in a nuclear waste repository, each waste form must be well characterized with respect to its behavior in the environments expected to develop in the repository. This scoping study was designed to obtain a qualitative idea of how spent fuel cladding would respond to a hot water environment that could develop in a tuff repository at a time when temperatures have cooled to {approximately}95{degree}C and hot liquid water has infiltrated the repository horizon. That information would then be used to establish more definitive tests on cladding behavior in a tuff repository. For this study bundles of spent fuel cladding held together with a 304 stainless steel (SS) wrap were constructed which simulate the geometries and materials associations in a breached 304L SS container. They were exposed to 90{degree}C tuff-equilibrated Well J-13 water for periods of 2, 6, and 12 mo. During the experiments, the water level, temperature, conductivity, and pH were monitored on a regular basis. The water was also checked periodically for carbon (organic, inorganic, and later in the experiment Carbon-14) and zirconium. More extensive water analyses were carried out at the midpoint and completion of the experiments. 12 refs., 16 figs., 5 tabs.

Fatigue Crack Growth Rate Properties of SA508 and SA533 Pressure Vessel Steels and Submerged-Arc Weldments in a Pressurized Water Environment

Abstract: The Stage II fatigue crack growth rate (FCGR) properties of four base materials (SA508 Class 2a; SA533 Grade A, Class 2; SA508 Class 3a; and SA533 Grade B, Class 2 steels) and two automatic submerged-arc weldments (SA508 Class 2a and SA533 Grade A, Class 2) were developed in a pressurized water environment at 288°C (550°F) and 13.8 MPa (2000 psi) at load ratios of 0.20 and 0.50. The pressurized water environment FCGR properties of these four pressure vessel steels and two submerged-arc weldments were generally conservative compared with the appropriate Amerian Society of Mechanical Engineers (ASME) Section XI water environment reference curve. The growth rate of fatigue cracks in the four base materials, however, was considerably faster in the pressurized water environment than in a corresponding 288°C (550°F) baseline air environment. The growth rate of fatigue cracks in the two submerged-arc weldments was also accelerated in the pressurized water environment but to a lesser degree than that demonstrated by the corresponding base materials. In the air environment, fatigue striations were observed independent of the material and load ratio, while in the pressurized water environment some intergranular facets were present. The greater environmental effect on crack growth rates displayed by the base materials in comparison with the weldments was attributed to a different sulfide composition and morphology.

Apparatus for purifying water quality

Abstract: PURPOSE:To improve the water environment for fish or the like by efficiently removing foam generated, in a purifying apparatus using an aeration device or an oxygen supply device, by arranging a treated water send-out pipe having a specific shape in specific positional relation to a foam discharge pipe. CONSTITUTION:When a water quality purifying apparatus is arranged in a marsh, a basin or a fish farm and at least one of a stirring device 14 and an aeration device is operated and at least one of an ultraviolet sterilizing lamp 11, an ozone injection device and an oxygen supply device is operated, water is subjected to sterilization treatment and dissolved oxygen increases. At this time, a treated water send-out pipe 3 wherein the inner end part thereof having a foam separation pie 6 is bent upwardly in the apparatus and a foam discharge pipe 8 are arranged so that the upper end of the send-out pipe 3 is positioned at a height equal to or more than that of the lower end of the opening part of the foam discharge pipe 8. Therefore, the foam generated by stirring is separated by the foam separation pipe 6 to be taken out from the discharge pipe 8.

Propagation of delamination fatigue cracks in CFRP in water.

Abstract: The effect of a water environment on the near-threshold growth of delamination fatigue cracks was investigated with unidirectional laminates made from Ciba Geigy prepregs 914C (T300/914) and from Toray prepregs P305 (T300/#2500). Tests were carried out under mode I opening loading using double cantilever beam specimens. The crack growth rate was correlated to the equivalent stress intensity range without respect to the stress ratio. For 914C laminate, the crack growth rate in water was about one tenth of that in air in the power-law region. For P305 laminate, the effect of a water environment was small in the power-law region. Near the threshold, the crack grew slower in water than in air for both laminates. When the 914C laminate specimen was moisture-conditioned, the rate in water was about 300 times faster than that for the specimen in water without conditioning. These environmental effects were explained on the bases of fractography and fracture mechanisms.

Factors influencing fluorine absorption and excretion in people and animals

Abstract: Factors that make fluorine absorption and excretion easy or difficult from organisms of people and animals have been analysed. Fluorine is easily absorbed in presence of alimentary fat from soluble dust, from water environment, especially from an acid one. Compounds of calcium, magnesium, aluminium, microelements and various high protein diet make fluorine absorption difficult. Compounds that easily absorb fluorine, namely compounds of calcium, magnesium, aluminium, boron, phosphorus and vitamin C as well as climatic conditions (increasing perspiration) make fluorine excretion from organisms easy. Fluorine excretion is made difficult in the period of intensified mineralization and lactation processes. The age of the person is also important.

Formation of coating film

Abstract: PURPOSE:To obtain the titled coating film having excellent corrosion resistance and adhesivity in hot water environment, by coating an adherend with a coating film of a composition composed of a bisphenol-type epoxy polymer and a hardener and curing the coating film under specific condition in two steps CONSTITUTION:The objective coating film can be formed by coating an adherend with a composition composed of (A) an epoxy polymer derived from bisphenols of formula (R1 and R2 are H or 1-3C alkyl) and (B) a hardener, keeping the formed coating film at a temperature near normal temperature for <72hr and preliminarily curing the film by contacting with the hot liquid of <60 degC