11,023 research outputs found
Thermal conductivity and electrical resistivity of porous materials
Process for determining thermal conductivity and electrical resistivity of porous materials is described. Characteristics of materials are identified and used in development of mathematical models. Limitations of method are examined
Fluid mechanics of waste water disposal in the ocean
Outfall pipes into the ocean are analogous to chimneys in the atmosphere: they are each intended for returning contaminated fluids to the environment in a way that promotes adequate transport and dispersion of the waste fluids. A waste-water treatment plant and an adjoining outfall constitute a system for environmental control; it is practically never feasible to provide such complete treatment that an outfall is not necessary, nor is it common to depend entirely on an outfall with no treatment.
Although outfalls and chimneys are functionally similar, there are important differences in their relationships to the coastal waters and atmosphere respectively. Urban and industrial areas, generating waste water, are located along the shallow edge of the ocean, with often tens or even hundreds of kilometers of continental shelf between the shoreline and the deep ocean. The bottom slope on the shelf is typically less than one percent. Thus outfalls extending several kilometers offshore discharge into a body of water of large lateral extent compared to the depth, and are still remote from the main body of ocean water.
In contrast, most atmospheric contaminants are introduced at the base of the atmosphere and circulate throughout the whole atmosphere much more readily. Vertical convection mixes the troposphere rapidly in most places and the wind
systems circulate the air around the globe in a matter of weeks.
Outfalls and chimneys are useful in reducing pollutant concentrations only locally. Far away from the sources, it makes little difference how the pollutants are discharged. The decay times of the pollutants are important in the choice of effective discharge strategies. For example, the problems of very persistent contaminants such as DDT cannot be alleviated by dispersion from an outfall; such pollutants must be intercepted at the source and prevented from entering the environment. On the other hand, degradable organic wastes, as in domestic sewage, may be effectively disposed of through a good ocean outfall. Since the decay time is only a few days, potential problems are only local, and not regional or global
Overproduction of PDR3 Suppresses Mitochondrial Import Defects Associated with a TOM70 Null Mutation by Increasing the Expression of TOM72 in Saccharomyces cerevisiae
Most mitochondrial proteins are synthesized with cleavable amino-terminal targeting signals that interact with the mitochondrial import machinery to facilitate their import from the cytosol. We previously reported that the presequence of the F1-ATPase beta subunit precursor (pre-F1beta ) acts as an intramolecular chaperone that maintains the precursor in an import-competent conformation prior to import (P. Hajek, J. Y. Koh, L. Jones, and D. M. Bedwell, Mol. Cell. Biol. 17:7169-7177, 1997). We also found that a mutant form of pre-F1beta with a minimal targeting signal (Delta 1,2 pre-F1beta) is inefficiently imported into mitochondria because it rapidly folds into an import-incompetent conformation. We have now analyzed the consequences of reducing the pre-F1beta targeting signal to a minimal unit in more detail. We found that Delta 1,2 pre-F1beta is more dependent upon the Tom70p receptor for import than WT pre-F1beta is, resulting in a growth defect on a nonfermentable carbon source at 15°C. Experiments using an in vitro mitochondrial protein import system suggest that Tom70p functions to maintain a precursor containing the Delta 1,2 pre-F1beta import signal in an import-competent conformation. We also identified PDR3, a transcriptional regulator of the pleiotropic drug resistance network, as a multicopy suppressor of the mitochondrial import defects associated with Delta 1,2 pre-F1beta in a tom70Delta strain. The overproduction of PDR3 mediated this effect by increasing the import of Delta 1,2 pre-F1beta into mitochondria. This increased the mitochondrial ATP synthase activity to the extent that growth of the mutant strain was restored under the selective conditions. Analysis of the transcription patterns of components of the mitochondrial outer membrane import machinery demonstrated that PDR3 overproduction increased the expression of TOM72, a little studied TOM70 homologue. These results suggest that Tom72p possesses overlapping functions with Tom70p and that the pleiotropic drug resistance network plays a previously unappreciated role in mitochondrial biogenesis
Nonacquiescence in Immigration Decisions of the U.S. Courts of Appeals
Perhaps at no other time is the conflict between administrative agencies and courts placed in starker terms than in instances of nonacquiescence. In general, nonacquiescence refers to an agency\u27s refusal to follow a U.S. court of appeals precedent in subsequent factually similar cases arising within ( intracircuit ) or outside ( intercircuit ) the circuit which produced the adverse ruling. A nonacquiescence policy reflects a tension between an agency\u27s mandate to achieve uniformity and expediency in its administrative adjudications and the court\u27s obligation to safeguard equally the rights of litigants and nonlitigants. These basic issues have been the subject of considerable academi\u27 and legislative attention. To date, however, there has been no examination in academic circles of the policy and practice of nonacquiescence by the Immigration and Naturalization Service ( INS or the Service )
Citra Penjajahan Jepang di Indonesia yang Terpantul dalam Beberapa Novel Pramoedya
Images of Japanese troops which drawn by Pramoedya in his works indeed related with his own experiences. Pramoedya through his characters portrays his view on humanities. Pramoedya depicted the brutality of Japanese troops in their occupation in Indonesia. All Japanese propaganda delivered false messages and caused disasters for Indonesian people. Japanese culture retardation and their brutality made the author suffer and down. Even though his novels associate with anti Japanese occupation and patriotism among the youth, humanities issues in fact appear as a strong theme in all his works
Delivery Systems and Initial Dilution
The discharge of municipal waste into the ocean has
been practiced for many decades by coastal communities. There are basically two methods of transporting the waste from the treatment works to the discharge point: 1. via an outfall pipeline for effluent or sludge, and 2. for sludge, by means of barges or vessels
Fundamental study of transpiration cooling
Isothermal and non-isothermal pressure drop data and heat transfer data generated on porous 304L stainless steel wire forms, sintered spherical stainless steel powder, and sintered spherical OFHC copper powder are reported and correlated. Pressure drop data was collected over a temperature range from 500 R to 2000 R and heat transfer data collected over a heat flux range from 5 to 15 BTU/in2/sec. It was found that flow data could be correlated independently of transpirant temperature and type (i.e., H2, N2). It was also found that no simple relation between heat transfer coefficient and specimen porosity was obtainable
Viscous stratified flow towards a line sink
A theoretical and experimental investigation has been made for the problem of two-dimensional, viscous, incompressible, steady, slightly-stratified flow towards a line sink. The analytical solution was obtained from the Navier Stokes equations, the continuity equation, and the diffusion equation by making a boundary-layer-type assumption and by using a small perturbation technique based on a perturbation parameter proportional to the sink strength q. The effects of viscosity, diffusivity, and gravity have been included while the inertia effect is neglected in the zeroth order solution. The solution indicates that there exists a withdrawal layer which grows in thickness with the distance x from the sink at the rate x^(1/3) and that the velocity distributions u(y) are similar from one station x to another.
Twenty-five tank experiments were performed using water stratified by means of either salt or temperature. Detailed measurements of the velocity field were made by means of photographs of vertical dye lines. The experiments verify the shape of the velocity profiles as well as their similarity in x as predicted by the theory.
The applicability of these results to the problem of selective withdrawal from a reservoir is discussed and compared with nonviscous solutions by Yih (6) and Kao (7)
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