Showing papers on "Water environment published in 1990"

Retractable swim fin

Abstract: Swimming efficiency and safety in a water environment is achieved with the use of retractable swim fins (10) having a web-like member (14) rotatably interconnected to a shoe-like member (12). Latchkey (44) secures the web-like member (14) to the shoe-like member (12) in a downward swimming position. Release of latchkey (44) permits the web-like member (14) to rotate to an upward walking position. A natural swimming kick returns and latches the web-like member (14) to the swimming position.

Condensing phenomena of a single vapor bubble into subcooled water

Abstract: Experiments have been carried out to investigate direct contact condensation of saturated vapor bubbles introduced into a quiescent subcooled water environment. The experiments were performed for a range of pressures from atmospheric to 1 MPa, for subcooling from 10 to 70 K, and for initial bubble diameters of about 10 mm. Flow visualization by highspeed motion pictures was based on a frame-by-frame analysis. The photographs show that the successive shapes of the bubbles during their collapse histories proceeded from a sphere to a hemisphere, to an ellipsoid, to a sphere, and finally to collapse. Two-dimensional photographs clearly show that the cavities of the bubbles during their collapse histories proceeded from the bottom to the top. The time to collapse increased with increasing pressure difference. The rising velocities of the bubbles were essentially constant, with an overall range of 20–25 cm/s.

Method and apparatus for mariculture utilizing converted hopper barges or the like

Abstract: A new and unique method and apparatus for the farming of redfish and the like. The exemplary embodiment of the present invention teaches an apparatus comprising a converted hopper barge retrofitted to allow circulation of water surrounding the vessel within the habitation tank(s). The present invention further teaches a fully self-contained farming apparatus providing the optimum environment for mariculture including circulation, oxygenation, replenishing of the water as well as an apparatus designed to systematically feed the crop and dispensing antibiotics and other solutions into the water environment as needed. The apparatus is designed for floating transport to a shallow water area with optimal salinity, PH, and purity and then be partially submerged via the opening of large coffer passages. The passages include a barrier for preventing the escape of the crop, while allowing new water circulation of the habitat. The present system is designed to farm fingerling size fish to a marketable size as efficiently and quickly as possible; when the fish have been farmed to the desired size, the coffer doors are closed, water is removed from the farming tanks to allow the vessel to float, and the barge is transported an area where the fish may be harvested. the present apparatus may be used in the mariculture of a variety of marine species, and may also be used for the purification of shellfish such as oysters or the like in an alternative embodiment, which teaches the multiple stacking of oyster racks in the tank area.

Underwater housing and pressure compensation method and apparatus

Abstract: A method and apparatus for protecting a camera or other apparatus from a water environment with a flexible, pressure compensated bag-like housing which is maintained at a slight positive pressure. The housing is larger than its contents to permit the contents to be moved relative to at least one wall to activate controls by frictional engagement between the wall and control during the relative movement. The housing may be configured as a merchandising container for the contents.

Water quality management in the RSA: preparing for the future

Abstract: The uniform effluent standard approach is presently used in the RSA to control pollution from point sources. Water quality in the RSA is gradually deteriorating and social and economical changes taking place affect water quality and the way in which it is managed. A new approach, which combines the receiving water quality objectives and pollution prevention approaches, will be used in future to control pollution from both point and non-point sources. The receiving water quality objectives approach to control input of non-hazardous pollutants and the pollution prevention aproach to control input of dangerous or hazardous substances to the water environment will be used.

The use of protein as a carrier of methotrexate for experimental cancer chemotherapy. V. Alternative method for preparation of serum albumin-methotrexate derivative.

Abstract: An alternative method for the preparation of human serum albumin-methotrexate derivative (HSA-MTX) using N-hydroxysuccinimide ester of methotrexate (MTX) was compared with that using the water-soluble carbodiimide (WSC) assistance. The prepared derivative was tested to find the advantages and drawbacks of this method. The N-hydroxysuccinimide ester method is more laborious than that using WSC but some reasons speak in favor of this method. The formation of protein-protein conjugates during the reaction was negligible and under specific conditions more MTX molecules could be bound to protein than by the WSC method. However, some disadvantages of this method were found: A laborious preparation, a small degree of denaturation of protein during the synthesis and, moreover, the binding of MTX to protein did not always take place through NH2-groups of protein but through some other groups (--OH, --SH) as well. These couplings were not so stable as an amidic (or peptidic) bond. In water environment they were hydrolyzed and MTX was slowly released. If there is no difference in a small fraction of protein-protein conjugates, the WSC-assisted method possesses evident advantages over the active MTX ester one, mainly because of the simple preparation of the stable derivative.

The water environment and implications for productivity

Abstract: Water deficits constrain productivity of herbi- management of the soil surface on the water constraint. vores on savanna grassland in two ways. The lack of soil It is concluded that the substantial progress in reducing water in the dry season causes a nutritional stress due to nutritional stress of the annual dry season has changed the the low protein concentration and low dry matter nature of the problem of periodic droughts. Whereas digestibility of dead tropical perennial grass tissue. Less formerly the main impact of nutritional stress was high frequently, lack of rain in the growing season causes feed cattle mortalities, now genetically better adapted cattle shortages in the subsequent dry season. The first part of survive by consuming a greater proportion of the low- this paper deals with simulation of these effects using quality herbage with the aid of mineral supplements. The weather data and describing the variation which occurs in sowing of legumes increases average carrying capacity and northern Australia. increased pasture utilization. Options for reducing the impact of the annual dry season Both innovations increase the risk of overgrazing in include sowing a pasture legume, since dry legume leaf is years of below-average pasture production. Avoidance of relatively nutritious. The second part of the paper examines accelerated land degradation as a result of loss of buffering variation imposed by the water climate on legume produc- capacity inherent to the former extensive system will tion potential and on the risk of spoilage due to out-of- require skilful management. season rainfall.

Influence of Aqueous Environment on Surface Molecular Mobility and Surface Microphase Separated Structure of Segmented Poly(ether urethanes) and Segmented Poly(ether urethane ureas)

Abstract: Segmented poly(ether urethanes) (SPUs) and segmented poly(ether urethane ureas) (SPUUs) with various hard and soft segment components were prepared. The surface characterization of SPU and SPUU in aqueous environment was done by means of X-ray photoelectron spectroscopy, XPS and dynamic contact angle measurements. XPS revealed that in the hydrated state, the component with the higher surface free energy is enriched on the surfaces of SPU and SPUU in order to minimize the interfacial free energy. The SPU and SPUU with hydrophilic soft segment showed the large increase in surface tension after immersing in water environment. It has been revealed that the surface molecular mobility reflects the bulk molecular mobility. Also, the effect of introduction of a fluorocarbon-containing diol into hard segment was investigated. The fluorocarbon chains in the diol of the hard segment did not influence the surface characteristics of SPU due to the bulky structure of diphenylmethane group.

Defensive secretions from the larvae of Apatania fimbriata (Pictet) (Trichoptera: Limnephilidae).

Abstract: When the larvae of the caddis flyApatania fimbriata (Pictet) are threatened, drops of fluid appear on their head capsules. The secretions are produced in a gland in the dorsal part of the prothorax. The neck region contains an eversible sac with numerous single setae, groups of 3 setae, or rows of setae on the surface. The secretion is released through two paris of orifices on the lateral sides of the sac. For the most part the secretion is composed of some 30 fatty acids, with the major components having 12–14 carbon atoms and up to 4 double bonds (approx. 1–2 µg secretion per specimen). Biotests with synthetic saturated acids (C6–C12) in a stream and in the laboratory demonstrated a paralysing effect on small invertebrate predators (Rhyacophila sp.,Plectrocnemia conspersa, Hydropsyche sp., larvae, all Trichoptera). In choice experiments,Rhyacophila sp. larvae preferred larvae ofAgapetus fuscipes andDrusus annulatus (Trichoptera) as food as compared withApatania fimbriata larvae. Larger predators, such asDinocras cephalotes (Insecta, Plecoptera) and the fishCottus gobio, did not discriminate betweenApatania fimbriata and other prey species. The use of fatty acids in defensive secretions is interpreted as an adaptation to the running water environment. They are effective repellents againstRhyacophila sp. larvae, the most important predator in the natural environment ofApatania larvae.

Cardiac output and heart rate in man during simulated swimming while breath-holding.

Abstract: We measured stroke volume (SV), heart rate (HR), cardiac output (Q), arterial pressure and intrapulmonic (mouth) pressure in four healthy, male subjects during simulated swimming (i.e., performing crawl movements with the legs continuously at a constant rhythm) with and without apnea (water temperature: 31 degrees C). We wanted to see whether the exercise tachycardia response persisted, or whether the HR decreased during apnea, just as in the "diving response" of diving animals. The SV and the Q fell to half its value in the control phase (i.e., swimming with normal breathing), when the 15-s apnea was performed at a high mouth-pressure; at low mouth-pressure, SV and Q hardly changed. These results are replicates of our previous findings in man during rest in air. Due to the light work, HR increased slightly from rest, but the exercise HR did not change much during apnea with or without high mouth-pressure. The results show that man tends to preserve his exercise HR response, and does not react as an oxygen-conserving animal, whether he is in air or in water under these conditions. However, man, as well as diving animals, may well have a "diving response" as an emergency reaction, which may not be restricted to only the water environment.

Temperature as an environmental factor influencing the pathogenicity of Aeromonas hydrophila.

Abstract: Contamination of wounds by surface water and the aspiration of such water following an accident can lead to severe septic infection by A. hydrophila. As such water is often found at low temperatures, the question should be asked whether this particular water environment influences the pathogenicity of this organism. Some experiments have been undertaken to assess if the pathogenicity of A. hydrophila is affected by temperature. The pathogenicity of A. hydrophila adapted to the low temperature of ground and surface waters (10 degrees C) was tested in a mouse-model. The conclusions drawn from the experimental data indicate that the 50 per cent lethal dose of A. hydrophila suspensions are lower for those grown at low temperatures (10 degrees C) when compared to those grown at higher temperatures (30 degrees C). The generation and log phase periods support the above conclusion, in so far that low-temperature-adapted organisms, when exposed to high temperatures, grow faster than those organisms already adapted to higher temperatures.

Equibiaxial Stress Effect on Fracture Strength of Indented Soda‐Lime Glass in Water Environment: An Examination for Dependence on Crack‐Tip Blunting

Abstract: Equibiaxial stress effects were observed in constant stressing rate tests of indented soda-lime glass in a water environment. To discuss whether the equibiaxial stress effects on fracture strenght in a water environment were caused by the blunting of crack tips by chemical reaction between the glass and moisture, the specimens with controlled surface flaws soaked in hot water to make the crack tip blunt were fractured under both uniaxial and equibiaxial tensile stresses under both vacuum and air environments. The biaxial strengthening observed under restricted subcritical crack growth indicates that equibiaxial stress effects in a water environment are caused by the rounding of the initial crack tip.

Strength degradation of steel-adhesive-joint in water environment.

Abstract: The strength degradation of steel adhesive joint in water environment was investigated. A model is proposed in which the process of progressive decrease in joint strength due to water uptake is considered as that of progressive growth of an apparent crack at the joint interface, and the strength degradation of adhesive joint can be analysed on the basis of fracture mechanics.It was found that in the specimens immersed in water for the same duration of time, the depth of the apparent crack increased with increasing water temperature, while the water concentration at the tip of respective crack was nearly the same. The fracture strength after immersing the joint in water at various temperatures was determined as a function of a single variable of Dt. The effect of side diffusion on the joint strength is not negligible in the case of longer immersion, especially at higher temperatures.

Effectiveness of the Space Shuttle anti-exposure system in a cold water environment.

Abstract: The purpose of this study was to evaluate the National Aeronautics and Space Administration (NASA) Space Shuttle Launch Entry Suit (LES) and raft for 24 h of protection against cold water immersion. Two configurations, the LES and the LES with raft (Navy LRU-18/U with NASA spray shield) were evaluated for anti-exposure protection. Conditions were selected to simulate worst case water and air temperatures along projected Space Shuttle ground tracks; i.e., water temperatures = 4.4 degrees C (40 degrees F), air temperature = 5.6 degrees C (42 degrees F), 1 foot waves (chop), and constant spray. Four males, 31-44 years of age, and one 32-year-old female, were studied once in each configuration. Trials with and without a raft were scheduled for up to 24 and 6 h, respectively. Mean LES trial durations were 150 +/- 9 min and final rectal temperature (Tre, f) = 36.5 +/- 0.3 degrees C. Mean LES with raft (LES/r) trial durations were 398 +/- 126 min and final rectal temperature (Tre, f) = 35.6 +/- 0.4 degrees C. LES and LES/r trials were terminated for reaching Tre = 35.0 degrees C or subject-requested termination due to discomfort. The longest LES and LES/r trials were terminated due to subject discomfort. Although not achieving the desired durations, the LES and LES/r did prove capable of protecting individuals, respectively, for up to 3 and 13.5 h. Since the longest LES and LES/r runs were terminated due to subjective tolerance and not physical incapacitation, actual survival times greater than 3 and 13.5 h, respectively, could be expected for individuals in these ensembles.

Dyed knitted fabric of alternating knitting and its production

Abstract: PURPOSE:To obtain the title knitted fabric having excellent chlorine water- resistant performance by dyeing knitted fabric of alternating knitting, comprising polyurethane-based elastic yarn containing a specific inhibitor of chlorine water deterioration and polyamide-based yarn so as not to make the system <=a specific pH value. CONSTITUTION:In dyeing knitted fabric of alternating knitting comprising polyurethane-based elastic yarn prepared by blending polyurethane-based elastic yarn with one or more of magnesium oxide, zinc oxide and aluminum oxide as an inhibitor of chlorine water deterioration and polyamide-based yarn with acid dye, pH of a dyeing bath is maintained above 4.5 from beginning to the end of the dyeing to give a knitted fabric of alternating knitting having excellent chlorine water-resistant performances to a chlorine water environment (e.g. swimming pool) while suppressing elution of the inhibitor.

Computer models for the detection of environmental changes

Abstract: Computer models are indispensable for the detection of environmental changes because of the large data sets and the complexity of the environmental processes. Unfortunately many of the processes related to the water environment cannot be modelled successlully, but computer-generated graphical presentations can provide valuable insight.

RIVER BASIN MANAGEMENT AND ITS SUPPORTING SYSTEM (2nd Report)

Abstract: In order to help the environmentally sound management of water regions and their basins, we are struggling to present a new supporting system. This system is made up by three parts; 1) watershed information system comprised of data base, some tools for handling the geographical data, and watershed indicies, 2) a number of models for predicting the future water environment, cost/results of some restoration practices, etc., 3) manual for proposing and giving priority to some reasonable plans of basin-wide management. In this first-report, the structure and functions of watershed information system are discussed and build up for Lake Kasumigaura's basin. In addition, the application of one runoff model (HSPF) to a small basin (9 km2) is examined.

The Sustainability of Aquaculture as a Farm Enterprise: Impacts and Consequences of Fish Culture in Rwanda.

Abstract: Rwanda, a small country in Africa, has experienced declines in per capita food production. Fish culture is one part of a many-stranded effort to increase food production and food security by intensifying the use of land resources to produce a much-needed protein crop. Beginning in 1983, the Rwanda National Fish Culture Project has assisted farmers with the upgrading of their fish ponds and identified and provided a species suitable for the high elevation, cool water environment. Average annual production among participants has been raised from 300 kilograms to 1,550 kilograms per hectare. New technologies like fish culture must conform with the environment and activities of the farming system. Thus,.rural extension is relevant in providing technological assistance to farmers. Data were obtained from 186 Rwandan farmers throughout the nation who had active ponds for 2 years and who received extension services during that period. Responses to the survey suggest a relatively uniform expectation for continuing fish culture, even though many factors affecting the sustainability of aquaculture as a farm enterprise are related to infrastructure beyond farmer control. A great deal of spontaneous emulation is occurring outside the project. Neighbors and relatives are constructing fish ponds, often without technical assistance. One threat to the evolution of fish culture is improperly constructed ponds. These ponds are too small, leaky, or have improper water temperatures, shortcomings that will undermine the success achieved by project participants. The paper discusses the necessary corrective or technical assistance to these emulators to avoid unnecessary failures. (ALL) *It:t******************************************************************** * Reproductions supplied by EDRS are the best that cal be made * * from the original document. * ***********************************************************************