High Inflow Rates Research Articles

Improving Infiltration of Irrigated Mediterranean Soils with Polyacrylamide

The effects of continuous (1·0 mg/l) and concentrated (10 mg/l) irrigation water-added polyacrylamide (PAM) on infiltration of a highly erodible Mediterranean soil were studied using recirculating furrow infiltrometers. Polyacrylamide avoided the seal formation observed in the wetted surface of the control furrow and helped to maintain higher infiltration rates for both PAM treatments. Mean final cumulative infiltration for the continuous and concentrated PAM experiments increased by 20 and 14%, respectively, as the result of reduced seal formation and surface sealing. Steady-state furrow infiltration rates, evaluated with disc infiltrometers 15 h after irrigation and under soil water tensions of 40 and 100 mm, confirmed the infiltration benefit of PAM treatments. Unsaturated hydraulic conductivity calculated under the same tensions revealed that the PAM-treated furrows were about 95% more permeable than the control. Polyacrylamide application also increased average saturated conductivity by 168% because of more unblocked pores in the treated furrows. The ability of PAM to influence surface soil conditions and improve infiltration can greatly enhance management of irrigated Mediterranean soils by allowing longer irrigation and higher inflow rates. Application of 10 mg/l in the inflow only during the advance phase of the irrigation can reduce labour, and ensures that loss of PAM from furrow tail water is minimized and that quantities applied during the season are reduced.

An Explanation of International Differences in Education and Workplace Training

We develop a simple search equilibrium model of workplace training and education based on two features. First, investment in education improves job-related learning skills and reduces training costs burdened by firms. Second, firms with vacant skilled job slots can choose between recruitment from the market and training. Compared to Germany and Japan, the US has both a higher inflow rate into unemployment and a higher efficiency of the matching process. While the combined effort of these differences on the share of educated labor is ambiguous, the effect on the percentage of firms undertaking workplace training is to unambiguously reduce it.

Accretion Disk Evolution with Wind Infall. II. Results of Three‐dimensional Hydrodynamical Simulations with an Illustrative Application to Sagittarius A*

In the first paper of this series, using analytic tools, we examined how the evolution and structure of a massive accretion disk may be influenced significantly by the deposition of mass and angular momentum by an infalling Bondi-Hoyle wind. Such a mass influx impacts the long-term behavior of the disk by providing additional sources of viscosity and heating. In this paper, we make a significant improvement over this earlier work by incorporating the results of three-dimensional hydrodynamical simulations of the large-scale accretion from an ambient medium into the disk evolution equations developed previously. We discuss in detail two models, one with the axis of the disk parallel to and the second with the axis oriented perpendicular to the large scale Bondi-Hoyle flow. We find that the mass inflow rate onto the disk within logarithmic annuli is roughly constant with radius and that the impacting wind carries much less specific angular momentum than Keplerian. We also find, in general, that the infrared spectrum of a wind-fed disk system is steeper than that of a Shakura-Sunyaev configuration, due mainly to the dissipation of the wind's kinetic energy at the disk's surface. In applying our results to the Galactic center black hole candidate Sgr A*, accreting from nearby stellar winds, we demonstrate that a high wind inflow rate of the order of 10-4 M☉ yr-1 cannot be incorporated into a fossil disk without a significant dissipation of kinetic energy at all radii. Such a high dissipation would violate current infrared and near-infrared limits on the observed spectrum of Sgr A*.

Focal delivery during direct infusion to brain: role of flow rate, catheter diameter, and tissue mechanics.

Direct interstitial infusion is a technique capable of delivering agents over both small and large dimensions of brain tissue. However, at a sufficiently high volumetric inflow rate, backflow along the catheter shaft may occur and compromise delivery. A scaling relationship for the finite backflow distance along this catheter in pure gray matter (x(m)) has been determined from a mathematical model based on Stokes flow, Darcy flow in porous media, and elastic deformation of the brain tissue: x(m) = constant Q(o)(3)R(4)r(c)(4)G(-3)mu(-1) 1/5 [corrected] = volumetric inflow rate, R = tissue hydraulic resistance, r(c) = catheter radius, G = shear modulus, and mu = viscosity). This implies that backflow is minimized by the use of small diameter catheters and that a fixed (minimal) backflow distance may be maintained by offsetting an increase in flow rate with a similar decrease in catheter radius. Generally, backflow is avoided in rat gray matter with a 32-gauge catheter operating below 0.5 microliter/min. An extension of the scaling relationship to include brain size in the resistance term leads to the finding that absolute backflow distance obtained with a given catheter and inflow rate is weakly affected by the depth of catheter tip placement and, thus, brain size. Finally, an extension of the model to describe catheter passage through a white matter layer before terminating in the gray has been shown to account for observed percentages of albumin in the corpus callosum after a 4-microliter infusion of the compound to rat striatum over a range of volumetric inflow rates.

Economics of Furrow Irrigation under Partial Infiltration Information

The effects of partial infiltration and furrow geometry information on furrow irrigation design and economic return to water were quantified on a single furrow (reference furrow) and field-wide (10-furrow set) basis using a kinematic-wave furrow irrigation model in conjunction with an economic optimization model. A furrow sampled at 10 locations was assumed to represent the actual field condition. Subsamples were randomly drawn from the 10 samples and return to water was maximized. These suboptimal designs were applied to the actual furrows and monetary loss due to lack of information was simulated. The monetary loss was less for furrow irrigation designs having high inflow rates ($0.38/furrow, $17/ha) than for the low inflow rates ($2.27/furrow, $100/ha). Average loss decreased from $31/ha ($0.71/furrow) to $0/ha in the case of the reference furrow, and from $1.0/furrow ($44/ha) to $0.3/furrow ($13/ha) in the case of the 10-furrow set for the samples sizes of 1 and 10, respectively.

Unemployment in Latin America and the Caribbean in the mid-90's

The paper presents a comparative analysis of unemployment incidence and duration in a cross section of countries in Latin America and the Caribbean. The analysis of time-series averages of unemployment rates shows that unemployment is heterogeneous across countries, and comparable to the level of developed countries with relatively flexible labor markets. Unemployment has moderately increased, and this is likely to be associated with changes in the relative prices of capital and labor that has resulted in slower employment growth. This has been partly compensated by slower labor supply growth. Labor markets in the region are quite fluid in terms of employment creation and destruction, as the high inflow and low long term unemployment rates show. Inflow rates are very similar across deciles (except for the lowest), but short-term unemployment is more prevalent in the lower ones. This suggests that the fundamental problem that high unemployment groups face do not result from more frequent job destruction (high inflow), but rather from experiencing difficulties finding a new job (low outflow).

商業基盤施設利用者の商店街利用率とイメージに関する研究

This study aims at the grasp of commercial basic facilities with a good effect for the shopping district activation. Concretely, it grasps the kinds thatincrease the inflow person to shopping districts from the investigation when the commercial basic facilities are introduced into the shopping districts. The result of investigated analysis (1) A athletic club a hospital, a post office, a bank and a library are effective to activate the shopping districts as the result of the analysis of the inflow rate investigation. (2) As the result of image investigation, facilities that raised the image of the town always do not correspond with the high inflow rate. (3) In commercial basic facilities made effective by the study, there are a lot of one which does not agree with commercial basic facilities specified by "The special measure low concerning the promotion of the maintenance of a specific, commercial accumulation". The expansion of the commercial basic facilities and the examination on the operation will be needed in the future.

Possible outburst floods from debris‐covered glaciers in the sierra nevada, california

A sequence of aerial photographs of Mendel Glacier, a debris‐covered glacier in the central Sierra Nevada, California, suggests that at least one outburst flood originated from a subglacial reservoir beneath a prominent mid‐glacier surface depression. By 1962, a ring of crevasses 250 m in diameter was centered within the depression, implying recent ice collapse. In 1972, the crevasses had almost disappeared, and by 1987, a lake of similar area had replaced the crevasse ring. No lake was present in 1995/6. Theoretical examination of ice overburden and hydrostatic pressure at the glacier bed indicate that a subglacial water reservoir may have formed beneath the surface depression prior to 1962. According to theory, as water accumulates within the reservoir, the hydrostatic pressure increases until it is equal to the ice overburden pressure down‐glacier from the reservoir, at which point an outburst flood initiates. Cesium‐137 measurements from the Mendel Glacier outwash plain indicate the post‐bomb‐testing deposition of approximately 20 cm of sand, lending support to the flood hypothesis. The supraglacial lake is ephemeral, and likely reflects relatively high inflow rates or low outflow rates. This sequence of events is possible because the debris cover reduces local ablation rates, forming a depression up‐glacier of the debriscover, which in turn forces water to flow into a subglacial reservoir. As long as the debris content is relatively low (<13% by weight), the reservoir water will eventually float the glacier and initiate an outburst flood. Debris‐covered glaciers should be recognized as potential sources of outburst floods in alpine regions.

A Note on the Viability of Gaseous Ionization in Active Galaxies by Fast Shocks

Morphological and spectroscopic evidence suggests that may affect the spatial and velocity distributions of gas in the narrow-line region (NLR) and the extended NLR of some active galaxies. It thus seemed plausible that may energize the NLR also. The observed emission-line ratios strongly favor photoionization as the heating source for this gas, but it is not clear whether the ionizing radiation is generated in the NLR by shocks or whether the ionizing radiation originates at the central continuum source. Here I point out that are highly inefficient in producing line emission. Shocks in the NLR can convert at most ~10-6 of the rest mass to ionizing radiation, compared with a maximum conversion efficiency of ~10-1 for the central continuum source. The required mass flow rate through shocks in the NLR is thus a few orders of magnitude higher than the mass accretion rate required to power the NLR by the central continuum source. Since gravity appears to dominate the NLR cloud dynamics, must lead to an inflow, and the implied high inflow rates can be ruled out in most active galaxies. NLR dynamics driven by a thermal wind or by some jet configurations may produce the mass flux through required for photoionizing to be viable, but the mass flux inward from the NLR must be kept ~100-1000 times smaller. Photoionizing are a viable mechanism in very low luminosity active galaxies if they are highly sub-Eddington (10-4) and if they convert mass to radiation with a very low efficiency (10-4).

Factors Affecting the Production of Carbon Monoxide in Inhalation Anesthetic Use

Factors Affecting the Production of Carbon Monoxide in Inhalation Anesthetic Use

The frequency and duration of episodes of complete vertical mixing in the Clyde Sea

A filling box model for the Clyde Sea in which buoyancy input by surface heating and freshwater inflow is opposed by stirring associated with surface wind stress, internal tide mixing and convection, has been driven using observed boundary conditions to simulate stratification in the area, for the period 1985–1990. The results show a well-defined seasonal cycle in stratification and cross-sill exchange. The model indicates two contrasting regimes: the summer regime during which cross-sill exchange is low and inflow is not sufficiently dense to sink below sill level, and so deep water conditions are only changed through mixing; and the winter regime when cross-sill inflow ventilates the whole water column and the deep water is replaced by North Channel water. The results suggest that at the time of switch-over between the summer and winter regimes, usually in November, the system becomes susceptible to an episode of complete vertical mixing as the water column stability is low due to an inversion in the temperature structure. Should the system fail to mix completely at this time, the high cross-sill inflow rates result in a reduction in temperature stratification and an increase in water column stability. Observations of an episode of complete vertical mixing, made in November 1990, show that in the four-day period when the water column was mixed, deep water temperatures dropped by 1.5°C. The competition between the re-stratifying influence of the baroclinic flow and convectively driven mixing at this time is examined in terms of a simple energetics model. It is demonstrated that the persistence of the completely mixed state is largely the result of convection caused by intense surface cooling, sustained by the large pre-existing heat reservoir in the deep water, which allowed a daily mean cooling rate >1 kW m −2.

Different protective effects of tauroursodeoxycholate, ursodeoxycholate, and 23-methyl-ursodeoxycholate against taurolithocholate-induced cholestasis

The coinfusion of tauroursodeoxycholate (TUDC) prevents taurolithocholate (TLC) -induced cholestasis. 23-Methyl-ursodeoxycholate (MUDC) is a side-chain derivative of ursodeoxycholate (UDC). If conjugation with taurine is important for the protective effect of UDC, the MUDC may not be as able as TUDC to prevent TLC-induced cholestasis since it is poorly amidated by the liver. To answer this question, isolated livers of adult Sprague-Dawley rats were coinfused with MUDC (UDC, TUDC) and TLC. After 15 min, inflow rates of the bile acids were doubled. In further experiments taurine in excess was added to the coinfused bile acids. The uptake of bile acids was >90% in all groups, irrespective of whether they were perfused alone or in combination. Single perfusion of TLC caused a rapid decrease in bile flow. UDC and MUDC were hypercholeretic; TUDC moderately choleretic. During coinfusion experiments, TUDC not only completely abolished cholestasis but in addition increased bile flow and biliary bile acid secretion. UDC did prevent TLC cholestasis at the lower inflow rates. At high inflow rates, bile flow decreased significantly. Addition of taurine to this bile acid combination did not significantly improve the anticholestatic effect of UDC. At low and high infusion rates of MUDC, cholestasis induced by TLC was reduced very little. Cumulative bile flow over 30 min fell by approximately 70% as compared to that of singly perfused MUDC. Addition of taurine to the coinfused MUDC/TLC slightly, but less significantly, improved the anticholestatic effect of MUDC. Since MUDC is by far less protective than UDC (and TUDC) despite similar physiochemical properties, it is concluded that taurine conjugation of UDC seems to be a prerequisite to prevent TLC-induced cholestasis. The results imply that treatment of cholestatic liver diseases with taurine-conjugated UDC might be more appropriate than with unconjugated UDC in cases where taurine conjugation is defective or where taurine depletion has occurred.

Effects of rearing conditions on growth and mortality of juvenile chum salmon (Oncorhynchus keta) infected with Ichthyobodo necator

Chum salmon (Oncorhynchus keta) juveniles, experimentally infected with the bodonid flagellate Ichthyobodo necator (Henneguy, 1883), were reared in 18-L tanks at three densities (300, 600, and 1200 fish) for 5 weeks. Water inflow rates were adjusted to give five combinations of crowding and flow rate. The parasite density on the fish body surface increased to 2700–4100 parasites-mm−2 over the course of the experiment and did not differ significantly among the groups. Total mortality was 76–90% in infected groups kept under the most unfavorable conditions (crowding or low water supply) but 11–15% in the other infected groups. The former groups also showed apparent growth reductions. In the uninfected controls, mortality was low (0.7–2.6%) and the degree of crowding or water supply had no significant effect on growth or mortality. Infected salmon were also much less resistant to seawater challenge; all fish kept at high stocking density or low inflow rate died in seawater. These results indicate that Ichthyobodo infections have marked effects on both host growth and survival when infections are combined with environmental stress induced by overcrowding and (or) inadequate water supply, although the parasite density is not affected by these factors.

Vltava cascade as teaching grounds for reservoir limnology

The empirical and modelling limnological studies of the reservoirs of the Vltava Cascade spanning over 30 years have demonstrated the major differences between stratified throughflowing reservoirs and lakes. The most significant limnological differences are caused by the generally deep outflows due to the extreme position of the maximum depths, and high flow rates causing flow-driven gradients. Limnological conditions in dam reservoirs are very sensitive to the theoretical retention time of water in the reservoir (RT), in particular in the range RT &amp;lt; 200 days. The primary effect of the high inflow rates is the weakening of stratification, due mainly to increasing bottom temperatures leading to deeper mixing, which results in lower surface temperatures. The hydrophysical changes subsequently affect the fate of chemical constituents and the primary production; the effects are propagated to higher levels and fed back to both chemical and physical water quality. A reservoir being second or successive in a cascade differs limnologically in that it is affected by the dominantly hypolimnetic releases of the upperlying reservoir. The differences in hydrophysics, hydrochemistry and hydrobiology have been specified and the findings are, in general, supported by modelling studies.

CONSEQUENCES OF THE BEHAVIOUR OF ACTIVATED SLUDGE PLANTS WITH COMBINED SEWAGE INFLOWS

The paper deals with the dynamic behaviour of activated sludge plants resulting from combined sewage inflows. Implications for the planning and operation of activated sludge plants are inferred from this behaviour. On the basis of a measured rain event dynamic simulation is used as a tool to investigate the influences of combined sewage inflows. Following an increase in the water inflow rate due to rain, a significant increase in concentration of nitrogen is observable at the outflow of the activated sludge tank The reason for this is the total Kjeldahl nitrogen influent load peak generated by the combined sewage inflow, together with displacement of biomass to the secondary sedimentation tank. Since the effluent concentration peaks are caused by inflow load peaks, measures must be taken to buffer these load peaks in the inflow zone. Best results can be achieved with inflow storage. Given a sufficiently large storage tank and optimum load management, a relatively low ammonium effluent value could be maintained even at high inflow rates. Optimum inflow control is feasible if both the water volume and the nitrogen concentration can be measured at the inflow and can be influenced by means of storage tanks. Dynamic simulation continues to be useful during operation, and can support tank control.

Control of Airborne Particle Concentration and Draught Risk in an Operating Room

The influence of location of airborne particle source, ventilation rate, air inlet size, supply air velocity, air outlet location, and heat source on the distributions of airborne particle concentration and draught risk in an operating room is investigated. The investigation is carried out by using flow program with the k-e model of turbulence. Based on a standard case, five cases, each with one changed parameter, are computed, and the detailed field distributions of air velocity, temperature, airborne particle concentration, and draught risk are presented. The parametric study concludes that, for a better air quality and thermal comfort, it is desirable to use a higher inflow rate, a larger inlet area, and a uniform velocity profile of supply air. Outlet location and heat source have little influence on the distributions ofthe particle concentration in the room. It has also been found that the distributions of particle concentration in the recirculating zone are very sensitive to the location of the particle sources.

Alveolar Oxygenation and Mouth-to-Mask Ventilation: Effects of Oxygen Insufflation

The effect on alveolar oxygen fraction (FAO2) of insufflating oxygen under a mask (or through an inflow nipple provided in the mask) during simulated mouth-to-mask ventilation was investigated using a lung model. A variety of commercially produced masks were evaluated. Two patterns of artificial ventilation were applied: 1. 500 ml tidal volume at 20 breaths per minute, and 2. 900 ml tidal volume at 12 breaths per minute. The ventilating gas mixture was oxygen 16% in nitrous oxide, and oxygen was insufflated at flow rates of 2, 4, 6, 8, 10, 12 or 14 litres per minute. The rate of rise of FAO2 and the equilibrium FAO2 attained were greatest at high oxygen inflow rates. The relationship between oxygen flow and FAO2 was not linear however, and an oxygen flow rate of 10 l/min was adequate to generate FAO2's around 50% with either ventilatory pattern. The equilibrium FAO2 achieved was greater with smaller tidal volumes and with larger mask deadspace. We also found that several breaths were required for equilibration of FAO2 during each trial, supporting recommendations that several breaths should be given on commencement of artificial ventilation during cardiopulmonary resuscitation.

Root-induced nitrogen mineralisation: A theoretical analysis

The possibility is examined that carbon (C) released into the soil from a root could enhance the availability of inorganic nitrogen (N) to plants by stimulating microbial activity. The release of soluble C compounds from roots is assumed to occur by one of two general processes: cortical cell death or exudation from intact cells. On the basis of several assumptions chosen to allow maximal amounts of N mineralisation to be calculated, greater amounts of net N mineralisation are theoretically possible at realistic soil C:N ratios of bacteria are grazed by predators such as protozoa, than if bacteria alone are active. More N is mineralised when the substrate released from the root has a high C:N ratio (as in cell death) than when it is relatively N-rich. The amounts of N that a root might realistically cause to be mineralised are unlikely to account entirely for high nitrate inflow rates that have been measured experimentally. However there are circumstances in which the loss of C from roots is essential if any N is to be mineralised and obtained by plants.

Patterns of reactive hyperemia in the hand

In normal individuals, the size and time course of the reactive hyperemia which occurs in the hand after occlusion of the circulation at the wrist was compared with that which follows simultaneous occlusion at the contralateral shoulder. In each case, the blood flow in the hand was measured by venous occlusion plethysmography, and the circulation was arrested for 3 minutes. It was found that the reactive hyperemia following shoulder occlusion was 16 per cent greater than that following wrist occlusion. This difference was interpreted as being due to a greater vasodilatation of hand vessels, as a myogenic response to the greater fall in arterial pressure measured at the wrist during shoulder occlusion. In the normal arm the maximum hyperemic flow at the extremity was delayed when the proximal parts were also undergoing reactive hyperemia. This delay was thought to be due to limitations imposed on the very high inflow rates by the normal artery.

Estimation of inspiratory capacity in health and in subjects with respiratory muscle paralysis

A method is described for the reproduction of the natural inspiratory capacity in healthy subjects utilizing a pressure breathing device capable of delivering high inflow rates at low pressures (1.3 l/sec. at 5 cm of water in the delivery system). A highly significant correlation was found between natural inspiratory capacity and the estimation of inspiratory capacity carried out in this manner in healthy subjects. The reliability of this method in cooperative individuals suggested applicability in patients with respiratory muscle paralysis when maximum natural inspiration is impossible. In poliomyelitis subjects with respiratory muscle paralysis the values of estimated inspiratory capacity were significantly reduced below those found in health. The degree of reduction was not directly related to the diminution of natural inspiratory capacity or to the maximum volume changes that could be produced by means of tank respirator assistance at comparable peak transthoracic pressures. Measurement of inspiratory capacity with this technique together with the determination of functional residual capacity makes it practical to estimate the total lung capacity and thus describe the lung compartments in such subjects. Submitted on June 10, 1958