Piezometric

Development Extension well QO (Step-out well) Development well Q (Production well) Service well 0 (Injection well, observation well, disposal well, etc.) Wells for production purposes - Production well 0 - Injection well 0 - Production- OO injection well - Appraisal well O - Piezometric well Special wells Disposal well O Absorptive well O Development well OOO Service well 0 Miscellaneous wells Appraisal well 00 (Extension well) Production well 0 (Exploitation well)... 

The NATA site consists of tailings overlying relatively low permeability clay soil, gravel-sand, and bedrock units. There are two aquifers one is confined between the bedrock and clay, and another unconfined aquifer which developed within the NATA tailings. Vertical exchange between aquifers is limited due to the clay separation. This is demonstrated by the higher piezometric levels of the unconfined aquifer compared to the confined one. 

A water table piezometric surface contour map is presented in Figure 12.18. The elevation of this surface varies from 10 to 40 ft below sea level across the facility. Groundwater occurring under water table conditions is first encountered between 30 and 60 ft in depth. The regional direction of flow of shallow groundwater is toward a depression in the piezometric surface of the Gage aquifer located about... 

If a reference datum plane (h = 0) is set at the bottom of each of the capillaries shown in the previous Fig. 5.5, the expression for the total driving force, that is the piezometric pressure difference along the penetration length h for a capillary with an upward (I pgh cos a) or a downward (—pgh cos a) orientation, can be represented by following equation (Bouchon and Pyle, 2005b),... 

H-n.m.r. [71], quasi-elastic neutron scattering [72], frequency response [73] and piezometric sorption uptake [34]. On the other hand, theself-consistency of data reported in [4,39,66,67] suggests further analysis of phenomena, probably interfered with bothithe samples and the experimental techniques used. 

The actinide metals up to californium were studied under pressure at room temperature (Fig. lb). For the lighter actinides up to plutonium, the (densest) room temperature allotrope remained in general stable under compression to the highest pressure attained (68 GPa for Th, 53 GPa for Pa, 21 GPa for Pu). a-U was stable up to about 50 GPa preliminary results indicate that at 71 GPa a different structure of uranium may exist. Np was only studied to 3.5 GPa by a piezometric technique. 

The pressure intensity is related to the piezometric pressure p, through the definition of the latter quantity ... 

Two parameters, that is, piezometric efficiency and ballistic efficiency are commonly employed in order to evaluate the overall performance of a particular gun-charge-projectile system and are defined in the following manner. 

Piezometric efficiency Piezometric efficiency is defined as the ratio of the mean pressure and the maximum breech pressure. The mean pressure is taken as that pressure which, if uniformly exerted upon the projectile over the entire length of the bore, will produce the observed muzzle velocity. Thus (Equation 4.2) ... 

In general, the pressure-travel curve becomes flatter with higher piezometric efficiency. 

Figure 15.4 Morphology of the piezometric surface obtained from both surface and deep boreholes piezometers.

Conventionally, molecular uptake is recorded gravi-metrically [18-20]. Alternatively, for a limited supply of adsorbate, molecular uptake may also be calculated from a knowledge of the time dependence of the pressure (piezometric method [21, 22]) or composition of the gas phase. Changing the sorbate pressure by a step change of the gas volume has proved to be a very efficient method for following fast sorption processes (single step method [23, 24]). The sorption uptake may also be measured volumctrically by mans of a gas burette arrangement [25]. 

Fig. 2.6 Components of a confined aquifer with through-flow tilted, or folded, water-bearing rock strata, sealed at the top and the base by aquicludes. Each active confined system also has a phreatic section at outcrops of the aquifer rocks. The level of the water table in the phreatic section defines the piezometric head in the confined section. Water ascends in boreholes drilled into confined aquifers. Water reaches the surface in artesian flow in boreholes that are drilled at altitudes lower than the piezometric head.

The level water reaches in an artesian well reflects its pressure, called the piezometric, or confined, water head (Fig 2.6). In boreholes drilled at altitudes that are lower than the piezometric head, water will reach the surface in a jet (or wellhead pressure) with a pressure that is proportional to the difference between the altitude of the wellhead and the piezometric head. The piezometric head is slightly lower than the water level in the relevant phreatic section of the system due to the flow resistance of the aquifer. Confined aquifers often underlay a phreatic aquifer, as shown in Fig. 2.7. The nature of such groundwater systems may be revealed by data measured in boreholes and wells. The water levels in wells 1 and 2 of Fig. 2.7 did not rise after the water was encountered, and both wells reached a phreatic aquifer. Well 3 is artesian, and the drillers account should include the depth in which the water was struck and the depth and nature of the aquiclude. The hydraulic interconnection between well 1 and well 3 may be established by... 

Fig. 11.10 Piezometric levels (in masl) of the Albian aquifer. Recharge seems to occur in the peripheries, giving rise to down-gradient flow toward Paris in the confined Albian aquifer. This hydrological hypothesis has been tested by 14C dating (Fig. 11.11). (Following Evin and Vuillaume, 1970.)...

Fig. 16.7 Piezometric water levels in waste injection and monitoring wells, and injection rates in Florida. (From Goolsby, 1971.)...

Pickens, J.F., Cherry J.A., Grisak, G.E., Merritt, W.F., and Risto, B.A. (1978) A multilevel device for ground-water sampling and piezometric monitoring. Ground Water 16, 322-327. 

The selection of impedance or admittance for presentation of experimental results and data analysis is dependent on the type of equivalent electric circuit. For instance, for the analysis of -> charge-transfer processes and -> double-layer charging, the impedance may be preferred, while for the resonance circuits (e.g., in piezometric systems) the admittance may offer advantages. 

Measurement of the transient adsorption or desorption curve for a sample of zeolite crystals exposed to a step change in ambient sorbate concentration (pressure) provides, in principle, a simple and direct method of measuring the intracrystalline diffusivity (D). Such measurements are conveniently carried out by gravimetric, volumetric or piezometric methods. The... 

Sorption Rates in Batch Systems. Direct measurement of the uptake rate by gravimetric, volumetric, or piezometric methods is widely used as a means of measuring intraparticle diffusivities. Diffusive transport within a particle may be represented by the Fickian diffusion equation, which, in spherical coordinates, takes the form... 

Piezometric ring— Pressure sensing holes that form a concentric circle around the center of the pipe. 

Brandani, S., Analysis of the Piezometric Method for the Stucfy of Diflusion in Microporous Solids Isothermal Case, Adsorption, 4, 17 (1998). 

In Fig. 18 the self-diffusivities obtained by different experimental techniques are compared. It appears that in both the absolute values and the trends in the concentration dependence, the QENS data, the PFG NMR results, and the data derived from sophisticated uptake experiments using the piezometric or single-step frequency-response techniques agree. Nevertheless, disagreement with some sorption results has to be stated. Additional information on the molecular reorientation of benzene in zeolite X has been obtained by QENS and NMR lineshape analysis. 

Fig. 18. Self-diffusion coefficients of benzene in NaX at 458 K PFG NMR, O (97) and (92) (JENS, A (13) deduced from NMR lineshape analysis, (10). Comparison with nonequilibrium measurements T, sorption uptake with piezometric control (93) , zero-length column method (96) o, frequency-response and single-step frequency-response technique (98). The region of the results of gravimetric measurements with different specimens (92) is indicated by the hatched areas. Asterisked symbols represent data obtained by extrapolation from lower temperatures with an activation energy confirmed by NMR measurements.

The oxidation of sulfide minerals appears to have been promoted by groundwater abstraction which has led to the lowering of the piezometric surface at a rate of —0.6 m yr since the 1950s, leading to partial dewatering of the confined aquifer. The high arsenic concentrations occur where the piezometric surface intersects, or lies close to, the sulfide cement horizon (Schreiber et al., 2000). 

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