980 resultados para Rock surfaces


Relevância:

20.00% 20.00%

Publicador:

Resumo:

A resident within one of the counties in your region has expressed some concern regarding potential adverse health effects from dust and material that may be found within foundry slag that has been used as a replacement for road rock. This consultation includes a comparison of nuisance issues from dust generated from a road constructed of foundry slag and dust generated from a road constructed from typical road rock. This consultation also includes a discussion of the potential health effects of exposure of heavy metals from incidental ingestion of foundry slag.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Due to their numerous novel technological applications ranging from the example of exhaust catalysts in the automotive industry to the catalytic production of hydro- gen, surface reactions on transition metal substrates have become to be one of the most essential subjects within the surface science community. Although numerous applications exist, there are many details in the different processes that, after many decades of research, remain unknown. There are perhaps as many applications for the corrosion resistant materials such as stainless steels. A thorough knowledge of the details of the simplest reactions occuring on the surfaces, such as oxidation, play a key role in the design of better catalysts, or corrosion resistant materials in the future. This thesis examines the oxidation of metal surfaces from a computational point of view mostly concentrating on copper as a model material. Oxidation is studied from the initial oxidation to the oxygen precovered surface. Important parameters for the initial sticking and dissociation are obtained. The saturation layer is thoroughly studied and the calculated results arecompared with available experimental results. On the saturated surface, some open questions still remain. The present calculations demonstrate, that the saturated part of the surface is excluded from being chemically reactive towards the oxygen molecules. The results suggest, that the reason for the chemical activity of the saturated surface is due to a strain effect occuring between the saturated areas of the surface.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Même ouvrage.Livres 3 et 5. — Comparer Cat. imp., liv. 106, f. 21 (Xin fa suan shu, 100 livres).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Frank Reynolds was in charge of the Rock at Brock featuring the Guess Who and 7 other Canadian Bands, held on the back field at Brock. It was a geat affair, with 40,000 in attendance and few incidents. The student union rented every bus the City of St Catharines owned and took everyone home at 1 AM when the event ended.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

There were three purposes to this study. The first purpose was to determine how learning can be influenced by various factors i~ the rock climbing experience. The second purpose was to examine what people can learn from the rock climbing experience. The third purpose was to investigate whether that learning can transfer from the rock climbing experience to the subjects' real life in the workplace. Ninety employees from a financial corporation in the Niagara Region volunteered for this study. All subjects were surveyed throughout a one-day treatment. Ten were purposefully selected one month later for interviews. Ten themes emerged from the subjects in terms of what was learned. Inspiration, motivation, and determination, preparation, goals and limitations, perceptions and expectations, confidence and risk taking, trust and support, teamwork, feedback and encouragement, learning from failure, and finally, skills and flow. All participants were able to transfer what was learned back to the workplace. The results of this study suggested that subjects' learning was influenced by their ability to: take risks in a safe environment, fail without penalty, support each other, plan without time constraints, and enjoy the company of fellow workers that they wouldn't normally associate with. Future directions for research should include different types of treatments such as white water rafting, sky diving, tall ship sailing, or caving.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Cell surfaces of susceptible host species (Mortierella pusllla and Cboanepilora cucurbitarum ), resistant host (Pilascolomyces articulosus ), nonhost (Mortierella candelabrum ) and the mycoparasite (Piptocepilalis virginiana) were examined for sugar distribution patterns using light and fluorescent microscopy techniques. The susceptible host, resistant host and the mycoparasite species exhibited a similar sugar distribution profile; they all showed N-acetyl glucosamine and D-glucose on their cell wall surfaces. The nonhost cell wall surface showed a positive binding reaction to FITClectins specific for N-acetyl glucosamine and also for OI.-fucose, N-acetyl galactosamine and galactose. Treatment of these fungi with mild concentrations of proteinases (both commercial as well as the mycoparasiteproteinase) resulted in the revelation of additional sugars on the fungal cell walls. The susceptible host treated with proteinase expressed higher levels of N-acetyl glucosamine and D-glucose. The susceptible host also showed the presence of OI.-fucose, N-acetyl galactosamine and galactose. The proteinasetreated susceptible host cell walls also showed an increase in the levels of attachment with the mycoparasite. Treatment of the resistant host with proteinases revealed OI.-fucose in addition to N-acetyl glucosamine and D-glucose. Treatment of the nonhost cell wall with proteinase resulted in the exposure of low levels of D-glucose, in addition to sugars found on the untreated nonhost cell wall surface. The mycoparasite treated with proteinase revealed OI.-fucose, N-acetyl galactosamine and galactose on its cell surface in addition to the sugars N-acetyl glucosamine and D-glucose. Protoplasts were isolated from hosts and nonhost fungi and their surfaces were examined for sugar distribution patterns. The susceptible host and nonhost protoplast membranes showed all the sugars (N-acetyl glucosamine, D-glucose, (It.-fucose, N-acetyl galactosamine and galactose) tested for. The resistant host protoplast membrane however, had only N-acetyl glucosamine and D-glucose exposed. This sugar distribution profile resembles that exhibited by the untreated resistant host cell wall, as well as that shown by the untreated mycoparasite cell surface. Only susceptible host protoplasts were successful in attaching to the mycoparasite surface. Resistant host protoplasts did not show any interaction with the i mycoparasite cell surface. Both susceptible as well as resistant host protoplasts were incapable of attaching to agarose beads surface-coated with specific carbohydrates. The mycoparasite however, did attach to agarose beads surface-coated with either N-acetyl glucosamine, D-glucose/Dmannose or o:,- methyl-D-mannose. The relevance of the cell wall and the protoplast membrane in the light of the present results, in reacting appropriately to bring about either a susceptible, a resistant or a nonhost response has been discussed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The endocrine pancreas of the rock bass (Ambloplites rupestris) was examined by light and electron microscopy. Two cell types with staining properties similar to mammalian A and B cells, and a third, non-staining cell type were found in the spherical pancreatic islets that were surrounded by a connective tissue capsule and embedded in two small masses of exocrine tissue. From an analysis of the ultrastructure of the A and B cells, a secretory cycle for each of these cell types was proposed. The secretory cycle of the A cell consisted of three well defined stages: (1) A cell production stage: during which A granule formation occurred in the sacs of the Golgi apparatus and the cell was characterized by the presence of numerous secretory granules, some elements of lamellar endoplasmic reticulum, and a homogeneously granular nucleus. The cytoplasm contained few distended cisternae, variable numbers of free ribosomes, microtubules and small vesicles. (2) A cell release stage: during which the release of A granules occurred and the cell usually contained several large distended cisternae and variable numbers of secretory granules. Granule release mechanisms included exocytosis, by which individual granules were released into the extracellular space after their membranes fused with the plasmalemma, and emiocytosis, by which one or more granules were released into a large cisterna whose membrane fused with the plasmalemma and formed a pore through which the cisternal contents passed out of the cell. (3) A cell reorganization stage: during which the changeover from the release stage to the production stage occurred and the reorganization of organelles and membrane structures took place. The cell contained few secretory granules and numerous small endoplasmic reticular cisternae. The cytoplasm exhibited less electron density than either of the other two stages. The A granule after formation underwent a series of morphological changes which were described in four numerically identified phases. The secretory cycle of the B cell consisred of two stages: (1) B cell production stage: during which the B granule formation occurred in the sacs of the Go1gi apparatus. The cell was characterized by an irregular outline, the presence of numerous secretory granules, and an irregularly shaped nucleus which contained variable amounts of clumped chromatin. The cytoplasm contained moderate amounts of lamellar endoplasmic reticulum studded with ribosomes, several small vesicles, and an active Go1gi apparatus. (2) B cell release stage: during which the release of B granules occurred. The cell contained a rounded nucleus with dispersed chromatin, several distended endoplasmic reticular cisternae and a variable number of secretory granules. Granule release occu~ by emiocytosis and exocytosis similar to that found for the A cell.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mathematical predictions of flow conditions along a steep gradient rock bedded stream are examined. Stream gage discharge data and Manning's Equation are used to calculate alternative velocities, and subsequently Froude Numbers, assuming varying values of velocity coefficient, full depth or depth adjusted for vertical flow separation. Comparison of the results with photos show that Froude Numbers calculated from velocities derived from Manning's Equation, assuming a velocity coefficient of 1.30 and full depth, most accurately predict flow conditions, when supercritical flow is defined as Froude Number values above 0.84. Calculated Froude Number values between 0.8 and 1.1 correlate well with observed transitional flow, defined as the first appearance of small diagonal waves. Transitions from subcritical through transitional to clearly supercritical flow are predictable. Froude Number contour maps reveal a sinuous rise and fall of values reminiscent of pool riffle energy distribution.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Three cores from the Kearl Lake Oil Sands area within the Athabasca deposit of northeastern Alberta have been analyzed to understand the thermal history of the McMurray and Clearwater formations of the Lower Cretaceous Mannville Group. The approach involves the integration of vitrinite reflectance (VR), Rock-Eval pyrolysis, fluorescence microscopy, and palynology. Mean VR varies between 0.21 and 0.43% Ro and indicates thermally immature levels equivalent to the rank of lignite to sub-bituminous coal. Although differing lithologies have influenced VR to some extent (i.e., coals and bitumen-rich zones), groundwater influence and oxidation seem not to have measurably altered YR. Rock-Eval analysis points to Type III/IV kerogen, and samples rich in amorphous organic matter (ADM) show little to no fluorescence characteristics, implying a terrestrial source of origin. Palynology reveals the presence of some delicate macerals but lack of fluorescence and abundant ADM suggests some degradation and partial oxidation of the samples.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

For inviscid fluid flow in any n-dimensional Riemannian manifold, new conserved vorticity integrals generalizing helicity, enstrophy, and entropy circulation are derived for lower-dimensional surfaces that move along fluid streamlines. Conditions are determined for which the integrals yield constants of motion for the fluid. In the case when an inviscid fluid is isentropic, these new constants of motion generalize Kelvin’s circulation theorem from closed loops to closed surfaces of any dimension.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A photograph of the construction at Baie Comeau, with the caption "'Sinking' dynamite for blast in rock immediately behind temporary staff house."