Showing papers on "Water flow published in 1977"
Book•
01 Jan 1977
TL;DR: The Light Environment of Plant Canopies Appendix as discussed by the authors describes the light environment of plant canopies in terms of temperature, wind, and water flow in the soil and water vapor and other gases.
Abstract: 1. Introduction 2. Temperature 3. Water Vapor and Other Gases 4. Liquid Water in Organisms and their Environment 5. Wind 6. Heat and Mass Transport 7. Conductances for Heat and Mass Transport 8. Heat Flow in the Soil 9. Water Flow in Soil 10. Radiation Basics 11. Radiation Fluxes in Natural Environments 12. Animals and Their Environment 13. Humans and Their Environment 14. Plants and Plant Communities 15. The Light Environment of Plant Canopies Appendix
3,373 citations
TL;DR: In this paper, the authors investigated the capabilities of the oxygen transport system of rainbow trout in supplying the increased oxygen demands in exercise, in a water tunnel at 9-10.5 °C, by increasing the velocity of water flow, with a 1 h period between increments, up to the maximum swimming speed (critical velocity, U crit ).
Abstract: 1. The capabilities of the oxygen transport system of rainbow trout in supplying the increased oxygen demands in exercise, in a water tunnel at 9–10.5 °C, have been investigated by increasing the velocity of water flow, with a 1 h period between increments, up to the maximum swimming speed (critical velocity, U crit ). 2. At U crit , N O2 was elevated above the resting level by 7.5 times. The logarithm of N O O2 was linearly related to the swimming speed expressed as a proportion of U crit . V g increased in almost direct proportion to the increase in N O O2 . 3. Heart rate rose slightly at half U crit and reached a maximum, 1.6 times the resting rate, as U crit was approached. Ventral and dorsal aortic mean blood pressures rose by 60% and 20% respectively at U crit while their pulse pressures doubled. Central venous pressure was virtually unchanged. 4. P a, O a, O2 fell slightly during exercise but C a, O a, O2 was unaffected. On the other hand P v, O v, O2 halved and C v, O v, O2 fell from 3.17 (S.E. = 0.3) to 0.6(S.E. = 0.7) mmol/1. Cardiac output increased by about 3 times resting values. 5. The results are discussed and an attempt is made to estimate the maximum capabilities of the components of the oxygen transport system in sustained exercise.
382 citations
TL;DR: In this article, the axisymmetric and spiral vortex breakdowns to imposed flow transients reported previously are confirmed, and are traced to the shedding of starting and stopping vortices from swirl vanes.
Abstract: Flow visualization studies and laser Doppler anemometer measurements on swirling water flows reveal six distinct types of very large amplitude disturbance modes of the vortex core. Three, ’’axisymmetric’’ and spiral vortex breakdowns, and the ’’double helix,’’ have been described by others. A definite order of evolution in parameter space (Reynolds number and circulations) occurs, and is described. Puzzling responses of the axisymmetric and spiral vortex breakdowns to imposed flow transients reported previously are confirmed here, and are traced to the shedding of starting and stopping vortices from swirl vanes. Conclusions bearing upon the validity of some theories of vortex breakdown are possible from the data.
368 citations
TL;DR: In this article, the authors used the concept of similar media to measure water flow in spatially varying soils, and found that the scaling parameter determined at a given sampling location for the soil water characteristic relationship (α from h(S)) should be identical to that for unsaturated hydraulic conductivity (αr from K(S)).
Abstract: With a view toward developing techniques for studying water flow in spatially varying soils, field data for soil water characteristic relationships and unsaturated hydraulic conductivity are scaled by using the concept of similar media. Data observed by different investigators at three geographic areas are used. The soil water characteristic data consisted of 840, 900, and 512 observations, while those for the unsaturated hydraulic conductivity (available from only one of the three sources) consisted of 2640 observations. In the process of scaling the data a best fit for the scaled data is defined in terms of a sum of squares about an ‘average’ curve using one value for the scaling parameter for each sampling location. Comparisons made between curves fitting the data and those fitting the scaled data show that scaling reduces the sums of squares by amounts varying from 34 to over 90%. For similar media the scaling parameter determined at a given sampling location for the soil water characteristic relationship (α from h(S)) should be identical to that for the unsaturated hydraulic conductivity (αr from K(S)). Although these parameters were highly correlated (r = 0.91 ) for the only set of data available, α r from h(S) values are shown to be more effective in scaling the unsaturated hydraulic conductivity data than are αr from K(S) values in scaling soil water characteristic data.
287 citations
Book•
01 Feb 1977
TL;DR: Finite element techniques for fluid flow, Finite element techniques with real-time application, اطلاعات رسانی کشاورزی, £20,000 (US$30,000; €40,000)
Abstract: Finite element techniques for fluid flow , Finite element techniques for fluid flow , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
226 citations
TL;DR: A review of cylinders in steady currents can be found in this paper, where the effects of length/diameter ratio, cylinder surface roughness and channel blockage are discussed, and the results of tests with pane and three-dimensional frames are described and quantified in terms of isolated cylinder data.
204 citations
TL;DR: Hatchery-reared brown trout (Salmo trutta L.) were exercised continuously for periods of several weeks at swimming speeds of 1-5, 3-0 and 4-5 body lengths/s and their rates of growth and changes in the major muscle constituents were determined.
Abstract: SUMMARY Hatchery-reared brown trout (Salmo trutta L.) were exercised continuously for periods of several weeks at swimming speeds of 1-5, 3-0 and 4-5 body lengths/s and their rates of growth were determined. Changes in the major muscle constituents were determined by biochemical analysis and changes in muscle cells using histochemistry and electron microscopy. At the lowest speed the fish grew much more rapidly, and converted food into fish flesh much more efficiently than their controls kept in still water. Large stores of glycogen and lipid were built up. Gross changes were observed mainly in red muscle cells, with enlargement of the mitochondria being very noticeable. The fish swimming at intermediate speed showed greater growth than the controls, although the energy expended in swimming against the water current led to an inefficient food conversion rate. Large stores of glycogen were built up, but lipid levels fell, suggesting that this was the major fuel for swimming at this speed. Changes in all the muscle fibre types were observed. The energy required to maintain the fish in the water flow at the highest speed was so great as to have serious detrimental effects on the fish, and many did not survive. Those which did survive showed signs of gross depletion.
149 citations
TL;DR: In this paper, the positions of the chloride and tritium as functions of soil depth and time were measured by extracting samples of the soil solution with soil suction probes, used to identify the rate at which a solute was displaced in the soil, will yield an estimate of the mean porewater velocity of this soil within a range of approximately ±25% of its true value providing the effects of potential solute-soil interactions are taken into account.
Abstract: Solute and water movement was studied under steady-state flow conditions in a field soil consisting of 70 cm of clay to silty clay over a medium sand. A steady-state water flow condition was maintained by applying irrigation water at a constant flux of 2 cm per day. During the steady-state condition some of the water leached into the plot was labelled with chloride and tritium. The positions of the chloride and tritium as functions of soil depth and time were measured by extracting samples of the soil solution with soil suction probes. Extremes in solute displacement occurred at equal and different depths within the plot. An analysis of these measurements indicated that observations of the pore-water velocity and the apparent diffusion coefficient were log normally distributed. Twenty-four soil suction probes, used to identify the rate at which a solute was displaced in the soil, will yield an estimate of the mean pore-water velocity of this soil within a range of approximately ±25% of its true value providing the effects of potential solute-soil interactions are taken into account.
133 citations
TL;DR: The water permeability response of the toad urinary bladder to vasopressin is inhibited by PGE synthesized by the bladder in response to vasipressin, which means that endogenous PGE inhibits basal and vasopressingin-stimulated adenylate cyclase activity.
Abstract: Prostaglandin E biosynthesis and its effect on water permeability were investigated in the toad urinary bladder. Arginine vasopressin (1 mU/ml) increased prostaglandin E (PGE) biosynthesis from 0.5+/-0.1 to 5.0+/-0.4 pmol/min per hemibladder (mean +/-SEM, n= 8, P less than 0.001). Maximal vasopressin-stimulated PGE biosynthesis, 6.4+/-0.2 pmol/min per hemibladder, occurred at vasopressin concentrations in excess of 3 mU/ml. Half-maximal stimulation of PGE biosynthesis occurred at a vasopressin concentration of approximately 0.7 mU/ml, whereas half-maximal stimulation of water flow occurred at a vasopressin concentration of approximately 5 mU/ml. Vasopressin-stimulated PGE biosynthesis did not depend on water flow along an osmotic gradient or upon sodium transport. Thin-layer chromatographic analysis of the lipids released from hemibladders labeled with tritium-arachidonic acid revealed that vasopressin stimulates the release of arachidonic acid from intracellular lipid stores without affecting the percentage of free arachidonic acid converted to PGE. Neither cyclic AMP nor theophylline stimulated PGE biosynthesis although they mimic arginine vasopressin (AVP) in stimulating water permeability. Biosynthesis of PGE was inhibited by mepacrine, a phospholipase inhibitor, and by agents that inhibit arachidonic acid oxygenase. The inhibition of PGE biosynthesis resulted in augmented vasopressin- and theophylline-stimulated water flow, but had no effect on cyclic AMP-stimulated water flow. We interpret these results to mean that endogenous PGE inhibits basal and vasopressin-stimulated adenylate cyclase activity. In contrast to the effects of AVP on permeability and transport, AVP stimulates PGE biosynthesis by a mechanism that does not depend on an increase in cellular cyclic AMP levels. The water permeability response of the toad urinary bladder to vasopressin is inhibited by PGE synthesized by the bladder in response to vasopressin.
119 citations
TL;DR: Analysis of net Na and K fluxes in the presence and absence of ouabain led to the conclusion that Na andK fluxes via both conservative and dissipative pathways are increased in response to osmotic swelling or shrinkage.
Abstract: The nucleated high K, low Na red blood cells of the winter flounder demonstrated a volume regulatory response subsequent to osmotic swelling or shrinkage. During volume regulation the net water flow was secondary to net inorganic cation flux. Volume regulation the net water flow was secondary to net inorganic cation flux. Volume regulation after osmotic swelling is referred to as regulatory volume decrease (RVD) and was characterized by net K and water loss. Since the electrochemical gradient for K is directed out of the cell there is no need to invoke active processes to explain RVD. When osmotically shrunken, the flounder erythrocyte demonstrated a regulatory volume increase (RVI) back toward control cell volume. The water movements characteristic of RVI were a consequence of net cellular NaCl and KCl uptake with Na accounting for 75 percent of the increase in intracellular cation content. Since the Na electrochemical gradient is directed into the cell, net Na uptake was the result of Na flux via dissipative pathways. The addition of 10(-4)M ouabain to suspensions of flounder erythrocytes was without effect upon net water movements during volume regulation. The presence of ouabain did however lead to a decreased ration of intracellular K:Na. Analysis of net Na and K fluxes in the presence and absence of ouabain led to the conclusion that Na and K fluxes via both conservative and dissipative pathways are increased in response to osmotic swelling or shrinkage. In addition, the Na and K flux rate through both pump and leak pathways decreased in a parallel fashion as cell volume was regulated. Taken as a whole, the Na and K movements through the flounder erythrocyte membrane demonstrated a functional dependence during volume regulation.
101 citations
TL;DR: Findings indicate that the phenomenon of particle aggregation is specifically related to vasopressin-induced water permeability and not to changes in urea or sodium permeability.
Abstract: It has been previously demonstrated with freeze-fracture electron microscopy that vasopressin induces specific structural alterations of the luminal membrane of granular cells from toad urinary bladder in a dose-dependent fashion. These alterations consist of aggregated intramembranous particles and are observed both in the presence and absence of an osmotic gradient. We examined the effect of methohexital, a selective inhibitor of vasopressin-stimulated water flow, and the effect of phloretin, a selective inhibitor of urea permeability, on the structure of the granular cell luminal membrane. Methohexital treatment of the vasopressin-stimulated toad bladder reduced both the osmotic water flow and vasopressin-induced alterations of membrane structure to the same extent. Phloretin reduced urea permeability but not water flow or particle aggregation. Since neither agent affects vasopressin-stimulated sodium movement, these findings indicate that the phenomenon of particle aggregation is specifically related to vasopressin-induced water permeability and not to changes in urea or sodium permeability.
TL;DR: The relative susceptibility of six species of salmonid fish to glochidiosis was determined by exposing fish individually to different numbers of parasites and plotting mortalities against these exposure levels at 70 days postexposure and also against the numbers of parasite recovered from fish 48 hr postinfection.
Abstract: The comparative susceptibility of 4 species of salmonid fishes, 30.5 to 87.0 mm in fork length, to the glochidia of the freshwater mussel (Margaritifera margaritifera) was determined by ex- amination of 594 caged and 178 uncaged (native) fish for infection. Of the caged fish, 99% of the chinook salmon (Oncorhynchus tshawytscha), 75% of the coho salmon (Oncorhynchus kisutch), 88% of the cutthroat trout (Salmo clarki), and 95% of the steelhead trout (Salmo gairdneri) were infected. There was a similar relationship in infection incidence in the native fish species. Mean infection in- tensities in the caged and native fish were: 446 and 399 for chinook salmon, 8 and 24 for coho salmon, and 72 and 88 for steelhead trout, respectively, and 212 for caged cutthroat trout (native juvenile trout were not captured). Glochidia completed development in mussels in the Siletz River, Oregon, in 13 days at an average water temperature of 12.8 C. They were released by these mussels from 13 May to 15 June 1971. During development in fish, the parasites increased in length by 500% from an initial size of 70 to 75 tum. Encysted parasites occurred in the gill filaments, arches, rakers, and occa- sionally in the pseudobranchs of all fish species; but most were in the lamellae of the filaments. Initially, the cyst walls were approximately 15 tLm in thickness, but as the parasites increased in size the ex- posed part of the wall became thinner. Up to 15 lamellae may be fused to the wall. Except for lamellae "grasped" by the parasites, blood apparently continued to flow through capillaries of the fused lamellae, but these lamellae, except the outermost ones, probably no longer functioned in respiration. Parasites encysted on the sides of gill filaments restricted blood flow by "pinching" the arterioles. Large en- cysted parasites on the lamellae increased the physiological dead space in the water flow. Clubbing of the filaments resulted when large parasites were located distally. These pathological changes in heavy infections may result in early death of fish by asphyxiation. In less heavy infections, the invading or exiting parasites may provide portals of entry for fungi, and delayed mortality may occur from sec- ondary infection.
TL;DR: Hypothetical curves relating temperature, food availability, and oyster growth are proposed and suggest that under ideal conditions and with high food availability maximum growth might be achieved at temperatures approaching 20°C.
TL;DR: In all species the trends from summer to fall were toward lower (more negative) osmotic potentials, lower matric potentials more rapid loss of turgor with increasing leaf water deficits, and the occurrence of incipient plasmolysis at lower values of leaf water deficit.
Abstract: Pressure volume curves were measured with a pressure bomb in leaves collected in the field from Ilex opaca, Acer rubrum, Liquidambar styraciflua, Liriodendron tulipifera and Cornus florida. Water potential components were calculated from the curves. The species differed in the relationships measured. In all species the trends from summer to fall were toward lower (more negative) osmotic potentials, lower matric potentials more rapid loss of turgor with increasing leaf water deficit, and the occurrence of incipient plasmolysis at lower values of leaf water deficit. Initial osmotic potentials ranged from-14.8 to-19.8 bars, similar to values reported in the literature for other mesophytic plants. These values, however, were much higher than those reported for halophytes and xerophytes. The fraction of leaf water which contributes to the osmotic potential ranged from 0.74 to 0.98 in this study. Values reported for other mesophytes and for halophytes and xerophytes all fall well within this range. Patterns of component water potentials are discussed in relation to potential growth rates and water flow in the total plant system.
TL;DR: The hydrogen-bubble technique has been used to measure the velocities of pulsating water flow in a rigid circular pipe as discussed by the authors, where mean flows with Reynolds numbers between 1275 and 2900 were superimposed on an oscillating flow produced by moving the pipe axially with simple harmonic motion.
Abstract: The hydrogen-bubble technique has been used to measure the velocities of pulsating water flow in a rigid circular pipe. Mean flows with Reynolds numbers between 1275 and 2900 were superimposed on an oscillating flow produced by moving the pipe axially with simple harmonic motion. While the velocities in the oscillating boundary layers on the pipe wall were found to be close to those predicted by laminar flow theory, at the higher Reynolds numbers the velocities near the centre of the pipe were lower than those predicted and more uniformly distributed.The intermittency of the periodic bursts of turbulent motion at the higher Reynolds numbers was measured. At each mean-flow Reynolds number the turbulent intermittency of the flow was found to be a function of a single parameter: the harmonicflow Reynolds number.
TL;DR: The membrane hydraulic conductivity of F. grandifolia leaves is roughly 10−6 cm s−1 bar−1 (1 bar = 100 kPa) and that water travels the shortest path between the cell sap and the nearest xylem vessel, flowing in and out of mesophyll cells through the areas in contact between adjacent cells along the pathway.
Abstract: The tempo of water efflux from single Fagus grandifolia leaves has been measured. The resistance to pressure-driven water efflux has been measured for normal leaves, Rs, and for leaves in which extracellular mesophyll spaces are infiltrated with water, Rs*. The ratio Rs*/Rs is about 0.4. The resistance to water flow through the xylem, Rx, was also measured and found to be a small part of Rs, i.e., Rx/Rs = 0.08. The activation energies for water efflux from normal and infiltrated leaves are both about 26 ± 4 kJ/mol.After an analysis of our data, we conclude that the membrane hydraulic conductivity of F. grandifolia leaves is roughly 10−6 cm s−1 bar−1 (1 bar = 100 kPa) and that water travels the shortest path between the cell sap and the nearest xylem vessel, flowing in and out of mesophyll cells through the areas in contact between adjacent cells along the pathway.
TL;DR: The house morphology and feeding behaviour of seven species of appendicularians was observed and photographed in the field and new information on the pattern of water flow through the house and mechanisms of food collection are presented.
Abstract: The house morphology and feeding behaviour of seven species of appendicularians was observed and photographed in the field. Details of house morphology varied greatly among species. New information on the pattern of water flow through the house and on mechanisms of food collection are presented. Flow rates through the house, ranging from 36 to 1400 ml/hour, may result in substantial depletion of phytoplankton locally.
TL;DR: Observations on the fresh water crayfish, a marine crab, and several species of fish, suggest that in aquatic animals the ventilatory activity depends greatly on the degree of water oxygenation, and the change of ventilation may be accompanied by a new equilibrium of the blood acid-base status, quite different from that observed in normoxia.
TL;DR: In this paper, the authors made measurements in 71 boreholes distributed over 5 km 2 near Noranda, Quebec and found that nearly 50% of the boreholes had some evidence of water flow along part of their total depth.
TL;DR: In this article, a finite element model of transient, partially saturated water flow within a hillslope soil mantle overlying an impermeable bedrock is used to make an investigation into the effects of parameter variations and initial conditions on the hillside hydrograph.
Abstract: Simulation models may be used to explore the implications of making specific assumptions about the nature of a real world system, and then to make predictions of the behaviour of that system under a set of naturally occurring conditions. It is important that understanding generated by the former should be gained before predictive use of the system model. This paper describes and uses a finite-element model of transient, partially saturated water flow within a hillslope soil mantle overlying an impermeable bedrock, to make an investigation into the effects of parameter variations and initial conditions on the hillslope hydrograph. The results clearly demonstrate that the response of the hillslope system to rainfall is highly non-linear and that the initial conditions, particularly in the unsaturated zone, are of paramount importance in governing the timing and magnitude of the hydrograph peak. Hillslope convergence appears as the dominant topographic parameter but the non-linearity of the response and the complex interdependence between the soil and topographic parameters restrict the possibility of further definite conclusions about the relative sensitivity of the simulated hillslope hydrograph to changes in these parameters.
TL;DR: None of the theories devised to account for the increase in min epp frequency predicts the falloff in frequency and in evoked quantal release that occurs in highly hypertonic solutions, and two theories do not fit with the results.
Abstract: 1. The time course for the changes in miniature end-plate potential (min epp) frequency and in epp amplitude produced by alterations in the tonicity of the Ringer at the frog neuromuscular junction was studied. The relations between the tonicity and min epp frequency as well as epp amplitude were also investigated. 2. The change in min epp frequency occurred within 1 min after the start of the change in the tonicity of the extracellular solution. Following a shift to a hypertonic solution, the min epp frequencies were often maintained at a relatively steady, elevated level, even with large (+100 mosM) changes in tonicity. In other instances the elevation was transitory like the reported data for the rat neuromuscular junction. Essentially the same results were obtained in very low Ca2+-Ringer. Unlike the rat neuromuscular junction, the final level after hours of the increased min epp frequency caused by raising the osmolarity by more than 75 mosM was well above the control level. Following the return from a hypertonic to an initial solution there was a prompt decrease in min epp frequency to about the initial level; there was no indication of the transitory depression in min epp frequency following the return from hypertonic solution that has been reported in mammals. 3. Until the osmolarity of the Ringer reached about 420 mosM, the frequency of min epp continued to rise along a line relating log (min epp frequency) to (osmolarity)0.5. When the osmolarity exceeded 460 mosM, the relation started to level off. 4. The hypothesis that the min epp frequency in a Ringer with a given increased tonicity is a fixed multiple of the frequency in normal Ringer is not in accord with the data. 5. The decrease in epp amplitude caused by markedly hypertonic solutions also came about within 1 or 2 min after the start of the change in the tonicity of the solution surrounding the nerve terminal. 6. Hypertonic solutions did not appear to affect facilitation. 7. Below 360 mosM increasing the tonicity of the Ringer had little effect on the amplitude of epp. Above this level the amplitude decreased as the tonicity increased. At a given junction an increase in tonicity in a range above 360 mosM can cause an increase in min epp frequency and a decrease in epp amplitude. 8. The results are discussed in terms of the theories proposed to account for the effects of osmolarity on synaptic function. Two theories--the water flow hypothesis (11) and the barrier of water hypothesis (2)--do not fit with the results. The two other theories--calcium elevation (1) and screening of surface charges (3, 13, 21)--fail to account for important aspects of the results and therfore cannot be accepted without substantial modifications. None of the theories devised to account for the increase in min epp frequency predicts the falloff in frequency and in evoked quantal release that occurs in highly hypertonic solutions.
Patent•
[...]
05 Dec 1977
TL;DR: Water supply line to the home has a water flow sensor therein and a valve therein. When water flow is sensed, the valve is turned off, as when a leak occurs as discussed by the authors, such as a burst pipe or leaky hot water heater, or may be caused by a disaster such as an earthquake.
Abstract: Water supply line to the home has a water flow sensor therein and a valve therein. When water flow is sensed, the valve is turned off, as when a leak occurs. Such a leak may be caused by failure of a component in the system, such as a burst pipe or leaky hot water heater, or may be caused by a disaster such as an earthquake.
TL;DR: The control of prey, thin syrup and water flow, through a society of Myrmica was studied and found that Starved nurse workers can obtain prey and water from foragers but a reverse flow does not occur; only thin syrup is exchanged freely between workers.
TL;DR: In this paper, the mean coliform density in a small-volume sample is estimated from coliform densities found in a series of small volume samples obtained over a period of time.
Abstract: water-treatment processes. There are two categories of samples: the mean coliform density in a smallvolume sample and the mean coliform density in a flow of water passing a particular point over some period of time. Usually, the primary interest is to obtain a measure of the mean coliform density in the raw water flow into a treatment plant or the finished water flow out of a treatment plant over a day's time. Since no method is available for counting each coliform organism in a flow of water, however, the mean coliform density in the flow of water is estimated from coliform densities found in a series of small-volume samples obtained over a period of time. The small-volume sample thus becomes the basic measurement.
Journal Article•
TL;DR: Paracellular pathways across “leaky” epithelia are the major route for transepithelial ionic diffusion and the permselective properties of these pathways suggest that they offer a watery environment through which ions diffuse in their hydrated forms.
Abstract: Paracellular pathways across “leaky” epithelia are the major route for transepithelial ionic diffusion. The permselective properties of these pathways suggest that they offer a watery environment through which ions diffuse in their hydrated forms. There is also suggestive evidence that, at least in some tissues, paracellular pathways provide a significant route for transepithelial water flow in response to an osmotic pressure difference; however, this has not as yet been definitively established. The effect of junctional complexes that are permeable to ions and water on the predictions of the standing-osmotic gradient model for isotonic water absorption is considered.
Patent•
27 Jun 1977
TL;DR: In this paper, a digital welder control system for controlling a portable gun welder of the type used in the automotive industry on an assembly line is described. But, it does not provide diagnostics for six common problems often encountered by welder controls such as override timeout, half cycling, transformer temperature rises, a low water flow, a shorted SCR, and a change in the heat settings.
Abstract: A digital welder control system for controlling a portable gun welder of the type used in the automotive industry on an assembly line. An 8 bit microprocessor is the main control element of the system. The known cycle time of the microprocessor is used to generate a real time delay which in turn is used to generate a digital phase shift heat control. RAM locations in the microprocessor are used to store medium constants of the welding sequence which were previously stored, in prior art controls, in the position of tap switches or thumbwheel switches. The controller provides diagnostics for six common problems often encountered by welder control systems such as override timeout, half cycling, transformer temperature rises, a low water flow, a shorted SCR, and a change in the heat settings. The controller also provides a maintenance interval counter and compensator control having a four-step stepper. The stepper control is used to automatically increase the weld heat after a preset number of welds to compensate for electrode mushrooming. The controller also checks the setting of address and data thumbwheels to prevent incorrect entries into the welding sequence. The controller also permits entry of data only into RAM locations which are used in the normal sequence of the welder. The controller also utilizes serial communication between a sequence module used to program the microprocessor and the microprocessor to economize on the number of drivers and receivers required and to reduce the power requirements of the controller.
TL;DR: The distribution and abundance of these two species of echinoids is significantly correlated with water flow over the reef and with detrital algae being deposited in their burrows.
Abstract: Echinometra oblonga and E. mathaei, two rock-burrowing sedentary echinoids, live in positive association on an Hawaiian algal reef. E. oblonga dominates in rough water, E. mathaei in calmer water. The distribution and abundance of these two species of echinoids is significantly correlated with water flow over the reef and with detrital algae being deposited in their burrows. The mean size of each species increased with increase in water flow. E. mathaei and E. oblonga show no significant difference in the rate in which biomass increases with test diameter.
TL;DR: Differences in sensitivity to both hormones were observed with gills from prespawning and postspawning salmon; gill from freshwater-adapted fish were less sensitive to norepinephrine and more sensitive to calcitonin, suggesting a decreased production of this hormone in the late stage of the life cycle.
Abstract: When isolated salmon gills were perfused under simulated in vivo conditions, norepinephrine increased and calcitonin decreased the rate of flow of perfusate and the influx of calcium and phosphate through the gill Only the increased water flow was mediated by β-adrenergic receptors Differences in sensitivity to both hormones were observed with gills from prespawning and postspawning salmon; gills from freshwater-adapted fish were less sensitive to norepinephrine and more sensitive to calcitonin, suggesting a decreased production of this hormone in the late stage of the life cycle The antagonistic effects of calcitonin and norepinephrine on the gill strongly implicate their regulatory role for calcium homeostasis in vivo; the major process being regulated is the influx of calcium into the gill In fish, calcitonin performs an important role in regulating gill function
TL;DR: In this article, measurements of noise from two-phase flow over hydrofoils were performed in a variable-pressure water tunnel which was acoustically calibrated so that sound power levels could be deduced from the sound measurements.
Abstract: This paper describes measurements of noise from two-phase flow over hydrofoils. The experiments were performed in a variable-pressure water tunnel which was acoustically calibrated so that sound power levels could be deduced from the sound measurements. It is partially reverberant in the frequency range of interest. Cavitation was generated on a hydrofoil in the presence of either a separated laminar boundary layer or a fully turbulent attached boundary layer. The turbulent boundary layer was formed downstream of a trip which was positioned near the leading edge. High-speed photographs show the patterns of cavitation which were obtained in each case. The noise is shown to depend on the type of cavitation produced.
TL;DR: It is concluded that the mechanism of enhancement on vasopressin-stimulated water flow by the sulfonylureas is the inhibition of prostaglandin E biosynthesis.
Abstract: Chlorpropamide is known to enhance the water permeability response of the toad urinary bladder to vasopressin and to theophylline In other studies, we have shown that prostaglandin E synthesis by the toad bladder inhibits the water permeability response to arginine vasopressin and to theophylline In this study, the effect of chlorpropamide on vasopressin-, theophylline-, and cyclic AMP-stimulated water flow and on prostaglandin E biosynthesis was investigated in the toad urinary bladder in vitro Chlorpropamide inhibited prostaglandin E biosynthesis during vasopressin-, theophylline- and cyclic AMP-stimulated water flow Tolbutamide and glyburide, two other sulfonylurea compounds, also enhanced vasopressin-stimulated water flow and inhibited vasopressin-stimulated prostaglandin E biosynthesis We conclude that the mechanism of enhancement on vasopressin-stimulated water flow by the sulfonylureas is the inhibition of prostaglandin E biosynthesis