Tidal velocity

In deriving this expression, was assumed to be symmetrically distributed about zero and to be statistically independent of the phase of the tide. For the currents near the floor of Long Island Sound, these characteristics of u have been demonstrated with field data (Bokuniewicz et al., 1975). The first term of (4.12) dominates the sum, and the relative magnitudes of the respective terms are 10 1 1. As a result, the net sand flux is approximately proportional to 1.5 uul. The direction of the average sand flux is controlled by the sign of the mean velocity although the magnitude of the sand flux is dominated by the amplitude of the tidal velocity. 

The decrease in the mean advection velocity is due, at least in part, to a decrease in the mean water velocity. The change could also be a manifestation of a decrease in the maximum tidal velocity and/or an increase in the critical erosion velocity due to decreasing mean grain size. [The maximum tidal velocity does decrease by about 12% (4 cm/sec) along the section.] Both of these phenomena would help to reduce the time that sand grains actually spend in motion and to lower the mean velocity of transport with a consequent decrease in the width of the transition zone. The width of the zone will also be decreased by an increase in the sedimentation rate or a decrease in the diffusion coefficient. 

Tidal and sub-tidal currents were examined using current profiles from three bottom-moored Sontek Acoustic Doppler Profilers (ADPs) deployed in the southern Yellow Sea in the summers of 2001 and 2003. The measured current time series were dominated by tidal currents. The maximum velocities were 40 80 cm/s at the mooring stations. The M2 current was the dominant primary tidal constituent, while the MS4 and M4 components produced the most significant shallow water tidal currents with much weaker amplitudes. The measured mean sub-tidal velocities were less than 5 cm/s. The mean flows in the lower layer implied that an anti-cyclonic circulation pattern might exist in the deeper central Yellow Sea (Liu ZL et al., 2008). 

Figure 6 is a contour map the average tidal velocity variation, compared with the pre engineering, flow velocity in the East west sides of Island increased. The maximum growth rate of about 0.3 m/s velocity decreases in south and north sides of island, the maximum reduction of about 0.5 m/s. 

In estuaries, it is concluded that a model should include tidal velocity variation, rather than lumping it all into Dl. If the estuary can be verified as 1-D, the MIT numerical model (18) should be used. If it is not 1-D, the best available options appear to be the Yeh-Tsai (104) or the Holley-Harleman (40) analytical solutions. However, questions still exist on coefficient selection, especially for the Yeh-Tsai model. 

Abstract. We present the first results of Call triplet observations from VLT/FLAMES for Sculptor, Fornax and Sextans dSphs. For each galaxy, we obtained accurate velocity and metallicity measurements for hundreds of stars out to and beyond the tidal radius. In each case, we find cfear evidence for the presence of two distinct steffar components with different spatiaf distribution and kinematics the metaf rich component is more centrally concentrated and kinematically colder than the metal poor one. 

In general, slow, deep inhalation followed by a period of breath holding increases the deposition of aerosols in the peripheral parts of the lungs, whereas rapid inhalation increases the deposition in the oropharynx and in the large central airways. Thus, the frequency of respiration (the flow velocity) and the depth of breath (tidal volume) influence the pattern of pulmonary penetration and deposition of inhaled aerosols. Therefore, an aerosol of ideal size will penetrate deeply into the respiratory tract and the lungs only when the aerosols are inhaled in the correct manner (Sackner, 1978 and Sackner et al., 1975). 

As noted earlier, air-velocity profiles during inhalation and exhalation are approximately uniform and partially developed or fully developed, depending on the airway generation, tidal volume, and respiration rate. Similarly, the concentration profiles of the pollutant in the airway lumen may be approximated by uniform partially developed or fully developed concentration profiles in rigid cylindrical tubes. In each airway, the simultaneous action of convection, axial diffusion, and radial diffusion determines a differential mass-balance equation. The gas-concentration profiles are obtained from this equation with appropriate boundary conditions. The flux or transfer rate of the gas to the mucus boundary and axially down the airway can be calculated from these concentration gradients. In a simpler approach, fixed velocity and concentration profiles are assumed, and separate mass balances can be written directly for convection, axial diffusion, and radial diffusion. The latter technique was applied by McJilton et al. 

For locating these ERWs, the most important characteristic of a body of water is its current. Currents may be nearly nonexistent in some stagnant ponds or irrigated fields. Currents in streams and rivers are usually consistent in direction but variable in velocity. Currents in tidal areas oscillate in direction and vary in velocity. Rapid currents have higher Reynolds numbers, hence more turbulence. Even rather modest velocities in water produce turbulence because the Reynolds number is higher with the higher density than in air. 

Male Fischer 344/N rats were exposed via the nose only for 6 h to concentrations of vinylidene fluoride ranging from 27 to 16 000 ppm [71-42 000 mg/m. Tidal volume (mean, 1.51 mL/brcath) and respiratory frequency (mean, 132 breaths/min) were not influenced by exposure concentration. Steady-state blood levels of vinylidene fluoride increased linearly with increasing exposure concentration up to 16 000 ppm. Vinylidene fluoride tissue/air partition coefficients were determined experimentally to be 0.07, 0.18, 0.8,10, and 0.29 for water, blood, liver, fat and muscle, respectively. Previously published detenninations (Filser Bolt, 1979) for the maximum velocity of metabolism in mg/li/kg) and Michaelis Menten constant (K in mg/L) are 0.07 and 0.13, respectively. Time to reach steady-state blood levels of vinylidene fluoride was less than 15 min for all concentrations. After cessation of exposure, blood levels of vinylidene fluoride decreased to 10% of steady-state levels within 1 h. Simulation of the metabolism of vinylidene fluoride mdicated that although blood levels of vinylidene fluoride increased linearly with increasing exposure concentration, the amount of vinylidene fluoride metabolized per 6-h exposure period approached a maximum at about 2000 ppm [5240 mg/m vinylidene fluoride (Medinsky et al., 1988). 

Kinematic Lengths + time intervals, or velocities Planetarium, tidal models... 

Figure 3.9 Stratification-circulation diagrams used to describe a spectrum of circulation and geomorphometric types of estuaries that can be defined by stratification. Estuarine types are as follows Type 1 estuaries are those without upstream flow requiring tidal transport for salt balance Type 2 estuaries are partially mixed (e.g., Marrows of the Mersey (NM) (UK), James River (J) (USA), Columbia River estuary (C) (USA) Type 3 estuaries are representative of fjords [e.g., Siver Bay (S), Strait of Juan de Fuca (JF) (USA)] and Type 4 estuaries indicative of salt wedge estuaries [e.g., Mississippi River (M) (USA)]. The basic classification parameters are as follows the stratification is defined by SS/Sq where SS is the difference in the salinity between surface and bottom water and So is the mean-depth salinity, both averaged over a tidal cycle and Us/Uf, where U is the surface velocity (averaged over a tidal cycle) and Uf is the vertically averaged net outflow. The subdivisions a and b represent values where SS/Sq <0.1 and SS/Sq >0.1, respectively subscripts h and 1 refer to high and low river flow. The curved line at the top represents the limit of surface freshwater outflow. (From Hansen and Rattray, 1966, as modified by Jay et al., 2000, with permission.)...

Figure 6.5 Distinct differences in transport behavior between pools of surface and bottom floes over several tidal cycles, as determined by R0 values, in the ACE Basin (USA). Hatched areas are times of maximum current speed. ws = sediment settling velocity, 0 = proportionality coefficient between eddy viscosity and diffusivity, k = von Karman s constant, and n = frictional velocity. (From Milligan et al., 2001, with permission.)...

Zappa, C J., Raymond, P.A., Terray, E.A., and McGillis, W.R. (2003) Variation in surface turbulence and the gas transfer velocity over a tidal cycle in a macro-tidal estuary. Estuaries 26, 1401-1415. 

End-tidal C02 (peak expired C02) is measured for each breath with a microcapnometer (Microcapnometer, model 0151-003L, Columbus Instruments, Columbus, OH, USA). This microcapnometer is uniquely suited for measurement of expired C02 in rats and other animals with low minute volumes (200-400 mL/min) since it utilizes relatively low flow rates (5 or 20 cc/min) compared with the standard capnometers that require 150-200 cc/min. This capability is achieved by using a low pressure, high velocity principle for analyzing the sampled gas. Airflow to the microcapnometer is maintained at 20 mL/min and is collected through a Teflon catheter (I.D. = 0.76 mm). Carbon dioxide concentrations are measured spectrophotometrically... 

The time, t, required for the passage of water across the Campbellrand platform is uncertain. The modern Bahamas are probably a reasonable analogue for the Campbellrand platform. On the Bahama Banks tidal currents of 25 cm s are common, and velocities of 1 m s have been recorded in channels (SeUwood, 1986). At a rate of 25 cm s it would have taken seawater —1 month (4 X 10" min) to traverse the —800 km diameter of the Campbellrand platform. This period is much longer than the time required to precipitate Fe oxyhydroxide after the oxidation of Fe to Fe (Grundl and Delwiche, 1993). The best estimate of the residence time of seawater on the Grand BahamaBankis —1 yr(Morseefa/., 1984 Millero, personal communication). The pH of the solutions from which the iron formations were deposited was probably less than that of seawater today, but probably not lower than 7.0. 

The northern part of the area with low tidal flows (u < 0.5 m/s) stratifies in the summer, but the area adjacent to the French coast remains mixed throughout the year due to the high tidal stream velocities (>2 m/s) (23). 

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