Investigatory Project “ Kaymito Leaves Decoction as Antiseptic Mouthwash ”

Topics: Aquifer, Hydrogeology, Fluid dynamics Pages: 10 (3511 words) Published: March 5, 2013
Introduction
1.1 Problem Statement
Fractures are prevalent in natural and synthetic structural media, even in the best engineered materials. We find fractures in bedrock, in sandstone aquifers and oil reservoirs, in clay layers and even in unconsolidated materials (Figures 1.1 to 1.4). Fractures are also common in concrete, used either as a structural material or as a liner for storage tanks (Figure 1.5). Clay liners used in landfills, sludge and brine disposal pits or for underground storage tanks can fracture, releasing their liquid contents to the subsurface (Figure 1.6). Even “flexible” materials such as asphalt fracture with time (Figure 1.7). The fact that fractures are inevitable has led to spending billions of research dollars to construct “safe” long-term (10,000 years or more) storage for high-level nuclear waste (Savage, 1995; IAEA, 1995), both to determine which construction techniques are least likely to result in failure and what are the implications of a failure, in terms of release to the environment and potential contamination of ground water sources or exposure of humans to high levels of radioactivity.

Why do materials fail? In most cases, the material is flawed from its genesis. In crystalline materials, it may be the inclusion of one different atom or molecule in the structure of the growing crystal, or simply the juncture of two crystal planes. In depositional materials, different grain types and sizes may be laid down, resulting in layering which then becomes the initiation plane for the fracture. Most materials fail because of mechanical stresses, for example the weight of the overburden, or heaving (Atkinson, 1989; Heard et al., 1972). Some mechanical stresses are applied constantly2 until the material fails, others are delivered in a sudden event. Other causes of failure are thermal stresses, drying and wetting cycles and chemical dissolution. After a material fractures, the two faces of the fracture may be subject to additional stresses which either close or open the fracture, or may subject it to shear. Other materials may temporarily or permanently deposit in the fracture, partially or totally blocking it for subsequent fluid flow. The fracture may be almost shut for millions of years, but if the material becomes exposed to the surface or near surface environment, the resulting loss of overburden or weathering may allow the fractures to open. In some cases, we are actually interested in introducing fractures in the subsurface, via hydraulic (Warpinski, 1991) or pneumatic fracturing (Schuring et al., 1995), or more powerful means, to increase fluid flow in oil reservoirs or at contaminated sites. Our particular focus in this study is the role that fractures play in the movement of contaminants in the subsurface. Water supply from fractured bedrock aquifers is common in the United States (Mutch and Scott, 1994). With increasing frequency contaminated fractured aquifers are detected (NRC, 1990). In many cases, the source of the contamination is a Non-Aqueous Phase Liquid (NAPL) which is either in pools or as residual ganglia in the fractures of the porous matrix. Dissolution of the NAPL may occur over several decades, resulting in a growing plume of dissolved contaminants which is transported through the fractured aquifer due to natural or imposed hydraulic gradients. Fractures in aquitards may allow the seepage of contaminants, either dissolved or in their own phase, into water sources.

Fluid flow in the fractured porous media is of significance not only in the context of contaminant transport, but also in the production of oil from reservoirs, the generation of steam for power from geothermal reservoirs, and the prediction of structural integrity or failure of large geotechnical structures, such as dams or foundations. Thus, the results of this study have a wide range of applications.

The conceptual model of a typical contaminant spill into porous media has been put forward by Abriola...

References: Atkinson, B. K., 1989: Fracture Mechanics of Rock, Academic Press, New York, pp. 548
Abdul, A
Bai, M., D. Elsworth, J-C. Roegiers, 1993: Multiporosity/multipermeability approach to the simulation of
naturally fractured reservoirs, Water Resources Research, 29:6, 1621-1633
Gelhar, L. W., 1986: Stochastic subsurface hydrology: From theory to applications., Water Resources Res.,
22(9), 1355-1455.
Gierke, J. S., N. J. Hutzler and J. C. Crittenden, Modeling the movement of volatile organic chemicals in
columns of unsaturated soil, Water Resources Research, 26:7, 1529-1547
Heard, H. C., I. Y. Borg, N. L. Carter and C. B. Raleigh, 1972: Flow and fracture of rocks,
Geophysical Monograph 16, American Geophysical Union, Washington, D
Hsieh, P. A., S. P. Neuman, G. K. Stiles and E. S. Simpson, 1985: Field determination of the threedimensional hydraulic conductivity of anisotropic media: 2. Methodology and application to fracture
rocks, Water Resources Research, 21:11, 1667-1676
Hsieh, P. A., S. P. Neuman and E. S. Simpson, 1983: Pressure testing of fractured rocks- A
methodology employing three-dimensional cross-hole tests, Report NUREG/CR-3213 RW, Dept
Hydrology and Water Resources, University of Arizona, Tucson, AZ 85721
IAEA, 1995: The principles of radioactive waste management, International Atomic Energy Agency,
Kueper, B. H. and D. B. McWhorter, 1991: The behavior of dense, nonaqueous phase liquids in fractured
clay and rock, Ground Water, 29:5, 716-728
Long, J. C. S., 1985: Verification and characterization of continuum behavior of fractured rock at AECL
Underground Research Laboratory, Report BMI/OCRD-17, LBL-14975, Batelle Memorial Institute,
Hydraulic conductivity and fracture aperture, Water Resources Research, 29:4, 1149-1162
Mercer, J
liquids: mass transfer characteristics, Water Resources Research, 26:11, 2783-2796
Mutch, R
National Research Council, 1994: Alternatives for ground water cleanup, National Academy Press,
Washington, D
National Research Council, 1996: Rock Fracture and Fracture Flow: Contemporary Understanding and
Applications, Committee on Fracture Characterization and Fluid Flow, National Academy Press,
Parker, J. C. and R. J. Lenhard, 1987: A model for hysteretic constitutive relations governing multiphase
flow: 1
Parker, J. C. and R. J. Lenhard, 1990: Determining three-phase permeability-saturation-pressure relations
from two-phase system measurements, J
Parker, B. L., R. W. Gillham and J. A. Cherry, 1994: Diffusive disappearance of immiscible-phase
organic liquids in fractured geologic media, Ground Water, 32:5, 805-820
Powers, S. E., C. O. Loureiro, L. M. Abriola and W. J. Weber, Jr., 1991: Theoretical study of the
significance of nonequilibrium dissolution of nonaqueous phase liquids in subsurface systems, Water
Reitsma, S. and B. H. Kueper, 1994: Laboratory measurement of capillary pressure-saturation
relationships in a rock fracture, Water Resources Research, 30:4, 865-878
Savage, D., 1995: The scientific and regulatory basis for the geological disposal of radioactive waste, John
Wiley, New York
Schuring, J. R., P. C. Chan and T. M. Boland, 1995: Using pneumatic fracturing for in-situ remediation
of contaminated sites, Remediation, 5:2, 77-90
Norman R. Warpinski, 1991: Hydraulic fracturing in tight, fissured media, SPE 20154, J. Petroleum
Technology, 43:2, 146-209
Warren , J. E. and P. J. Root, 1963: The behavior of naturally fractured reservoirs, Soc. Pet. Eng. J., 3,
245-255
Wilkins, M. D., L. M. Abriola and K. D. Pennell, 1995: An experimental investigation of rate-limited
nonaqueous phase liquid volatilization in unsaturated porous media: Steady state mass transfer, Water
Resources Research, 31:9, 2159-2172
Zimmerman, R
with semianalytical treatment of fracture/matrix flow, Water Resources Research, 29:7, 2127-2137
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • Investigatory Project “ Kaymito Leaves Decoction as Antiseptic Mouthwash ” Essay
  • Investigatory Project “ Kaymito Leaves Decoction as Antiseptic Mouthwash Essay
  • Essay about Kaymito leaves decoction as antiseptic mouthwash
  • Kaymito Leaves as Antiseptic Mouthwash Essay
  • Kaymito Leaves as Antiseptic Mouthwash Essay
  • Kaymito Leaves Decoction as Antiseptic Mouthwash Essay
  • Kaymito Leaves Decoction as Antiseptic Mouthwash Essay
  • Kaymito Leaves Decoction as Antiseptic Mouthwash Essay

Become a StudyMode Member

Sign Up - It's Free