985 resultados para Site investigations


Relevância:

60.00% 60.00%

Publicador:

Resumo:

Stormwater runoff is a major cause of surface water pollution in western Washington and cost-effective control measures are needed to reduce contamination of receiving waters. This project evaluated the performance efficiency and costs of installing a residential rain garden by inspecting two gardens and testing water quality samples in one. Infiltration through the garden was effective in reducing metals and nutrients as indicated by reductions in copper and nitrate concentrations of 75% and 97%, respectively. The costs were affordable for most homeowners and cost-effective compared to other options. After doing on-site investigations, the storm water manual for the State of Washington was reviewed and eight recommendations were made for improving it.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Construction companies are interested in adopting environmental methods, such as in situ bioremediation, when conducting remediation at petroleum contaminated sites. This interest is due to both the cost benefits associated with in situ bioremediation methods and the environmental movement. This project creates a comprehensive manual comprised of information about site investigations, treatability studies, design, and implementation of in situ bioremediation at petroleum contaminated sites. The training manual also provides information about regulatory requirements and permitting for petroleum contaminated sites.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Thesis (Master's)--University of Washington, 2016-06

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The aim of this project was to carry out a fundamental study to assess the potential of colour image analysis for use in investigations of fire damaged concrete. This involved:(a) Quantification (rather than purely visual assessment) of colour change as an indicator of the thermal history of concrete.(b) Quantification of the nature and intensity of crack development as an indication of the thermal history of concrete, supporting and in addition to, colour change observations.(c) Further understanding of changes in the physical and chemical properties of aggregate and mortar matrix after heating.(d) An indication of the relationship between cracking and non-destructive methods of testing e.g. UPV or Schmidt hammer. Results showed that colour image analysis could be used to quantify the colour changes found when concrete is heated. Development of red colour coincided with significant reduction in compressive strength. Such measurements may be used to determine the thermal history of concrete by providing information regarding the temperature distribution that existed at the height of a fire. The actual colours observed depended on the types of cement and aggregate that were used to make the concrete. With some aggregates it may be more appropriate to only analyse the mortar matrix. Petrographic techniques may also be used to determine the nature and density of cracks developing at elevated temperatures and values of crack density correlate well with measurements of residual compressive strength. Small differences in crack density were observed with different cements and aggregates, although good correlations were always found with the residual compressive strength. Taken together these two techniques can provide further useful information for the evaluation of fire damaged concrete. This is especially so since petrographic analysis can also provide information on the quality of the original concrete such as cement content and water / cement ratio. Concretes made with blended cements tended to produce small differences in physical and chemical properties compared to those made with unblended cements. There is some evidence to suggest that a coarsening of pore structure in blended cements may lead to onset of cracking at lower temperatures. The use of DTA/TGA was of little use in assessing the thermal history of concrete made with blended cements. Corner spalling and sloughing off, as observed in columns, was effectively reproduced in tests on small scale specimens and the crack distributions measured. Relationships between compressive strength/cracking and non-destructive methods of testing are discussed and an outline procedure for site investigations of fire damaged concrete is described.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The research concerned the assessment of the pathways utilized by heavy metal pollutants in urban stormwater runoff. A separately sewered urban residential catchment of approximately 107 hectares in Chelmsley Wood, north-east Birmingham was the subject of the field investigation. The catchment area, almost entirely residential, had no immediate industrial heavy metal input, however, industry was situated to the north of the catchment. The perimeter of the catchment was bounded by the M6 motorway on the northern and eastern sides and was believed to contribute to aerial deposition. Metal inputs to the ground surface were assumed to be confined to normal suburban activities, namely, aerial deposition, vehicular activity and anthropological activities. A programme of field work was undertaken over a 12 month period, from July 1983 to July 1984. Monthly deposition rates were monitored using a network of deposit cannisters and roadside sediment and soil samples were taken. Stormwater samples were obtained for 19 separate events. All samples were analysed for iron, lead, zinc, copper, chromium, nickel and cadmium content. Rainfall was recorded on site with additional meteorological data obtained from local Meteorological Offices. Use was made of a simple conceptual model designed for the catchment to substantiate hypotheses derived from site investigations and literature, to investigate the pathways utilized for the transportation of heavy metals throughout the catchment.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The purpose of the study was to evaluate the magnitude of environmental lead contamination in the downtown area of Miami. Lead inspections took place at 121 homes in Little Haiti and Liberty City and involved the collection ofrepresentative samples from floors, window wells, tap water, soil and air. Community health workers (CHWs) trained in interview and safety techniques went from door to door to enlist participation. On-site investigations were tailored to areas most utilized by children underthe age of6 years. The presence of lead-containing paint was also investigated in situ via X-ray fluorescence (XRF) analysis. Results: Of the sampling areas, the window wells area had the most abundant occurrence of lead. On analysis, 24% of sites returned window well samples with lead levels above Department of Housing and Urban Development (HUD) guidelines. Of the soil samples, the playgrounds around the house had the highest concentration of lead. Soil sampling demonstrated that 27.5% of sites returned samples with lead levels (400 to 1600 ppm) inexcess of HUD/Environmental Protection Agency (EPA) standards. Positive XRF readings in one or more components were returned by 18% of sites. Conclusions: More than half of the houses in these two neighborhoods exhibited unacceptably high levels of lead dust and soil in areas where children live and play. Limitations of this study did not allow the assessment of how many children in this area are affected. A more comprehensive study including other areas of Miami-Dade County with older housing stock is recommended.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The Pico de Navas landslide was a large-magnitude rotational movement, affecting 50x106m3 of hard to soft rocks. The objectives of this study were: (1) to characterize the landslide in terms of geology, geomorphological features and geotechnical parameters; and (2) to obtain an adequate geomechanical model to comprehensively explain its rupture, considering topographic, hydro-geological and geomechanical conditions. The rupture surface crossed, from top to bottom: (a) more than 200 m of limestone and clay units of the Upper Cretaceous, affected by faults; and (b) the Albian unit of Utrillas facies composed of silty sand with clay (Kaolinite) of the Lower Cretaceous. This sand played an important role in the basal failure of the slide due to the influence of fine particles (silt and clay), which comprised on average more than 70% of the sand, and the high content presence of kaolinite (>40%) in some beds. Its geotechnical parameters are: unit weight (δ) = 19-23 KN/m3; friction angle (φ) = 13º-38º and cohesion (c) = 10-48 KN/m2. Its microstructure consists of accumulations of kaolinite crystals stuck to terrigenous grains, making clayey peds. We hypothesize that the presence of these aggregates was the internal cause of fluidification of this layer once wet. Besides the faulted structure of the massif, other conditioning factors of the movement were: the large load of the upper limestone layers; high water table levels; high water pore pressure; and the loss of strength due to wet conditions. The 3D simulation of the stability conditions concurs with our hypothesis. The landslide occurred in the Recent or Middle Holocene, certainly before at least 500 BC and possibly during a wet climate period. Today, it appears to be inactive. This study helps to understand the frequent slope instabilities all along the Iberian Range when facies Utrillas is present.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

La0.5Li0.5TiO3 perovskite was synthesized by various wet chemical methods. By adopting low temperature methods of preparation lithium loss from the material is prevented. La0.5Li0.5TiO3 (LLTO) was formed with cubic symmetry at 1473 K. LLTO was formed at relatively lower temperature by using hydrothermal preparation method. PVA gel-decomposition route yield tetragonal LLTO on annealing the dried gel at 1473 K. By using gel-carbonate route LiTi2O4 minor phase was found to remain even after heat-treatment at 1473 K. The hydroxylation of LLTO was done in deionized water as well as in dilute acetic acid medium. By hydroxylation process incorporation of hydroxyls and leaching out of Li+ was observed from the material. The Li+ concentration of these compositions was examined by AAS. The electrical conductivities of these compositions were measured by dc and ac impedance techniques at elevated temperatures. The activation energies of electrical conduction for these compositions were estimated from the experimental results. The measured activation energy of Li+ conduction is 0.34 eV. Unhydroxylated samples exhibit only Li+ conduction, whereas, the hydroxylated LLTO show proton conductivity at 298-550 K in addition to Li+ conductivity. The effect of Zr or Ce substitution in place of Ti were attempted. La0.5Li0.5ZrO3 Perovskite was not formed; instead pyrochlore phase (La2Zr2O7) along with monoclinic ZrO2 phases was observed above 1173 K; below 1173 K cubic ZrO2 is stable. (La0.5Li0.5)(2)CeO4 solid solution was formed in the case of Ce substitution at Ti sublattice on heat-treatment up to 1673 K. (c) 2005 Springer Science + Business Media, Inc.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Long-term (2009-2012) data from ground-based measurements of aerosol black carbon (BC) from a semi-urban site, Pantnagar (29.0 degrees N, 79.5 degrees E, 231 m amsl), in the Indo-Gangetic Plain (IGP) near the Himalayan foothills are analyzed to study the regional characterization. Large variations are seen in BC at both diurnal and seasonal scales, associated with the mesoscale and synoptic meteorological processes, and local/regional anthropogenic activities. BC diurnal variations show two peaks (morning and evening) arising from the combined effects of the atmospheric boundary layer (ABL) dynamics and local emissions. The diurnal amplitudes as well as the rates of diurnal evolution are the highest in winter season, followed by autumn, and the lowest in summer-monsoon. BC exhibits nearly an inverse relation with mixing layer depth in all seasons; being strongest in winter (R-2 = 0.89) and weakest (R-2 = 0.33) in monsoon (July-August). Unlike BC, co-located aerosol optical depths (AOD) and aerosol absorption are highest in spring over IGP, probably due to the presence of higher abundances of aerosols (including dust) above the ABL (in the free troposphere). AOD (500 nm) showed annual peak (>0.6) in May-June, dominated by coarse mode, while fine mode aerosols dominated in late autumn and early winter. Aerosols profiles from CALIPSO show highest values close to the surface in winter/autumn, similar to the feature seen in surface BC, whereas at altitudes > 2 km, the extinction is maximum in spring/summer. WRF-Chem model is used to simulate BC temporal variations and then compared with observed BC. The model captures most of the important features of the diurnal and seasonal variations but significantly underestimated the observed BC levels, suggesting improvements in diurnal and seasonal varying BC emissions apart from the boundary layer processes. (C) 2015 Elsevier Ltd. All rights reserved.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

In celebration of the 250th anniversary of the birth of Charles Carroll of Carrollton, Archaeology in Annapolis was invited to excavate the Carroll House and garden on 107 Duke of Gloucester Street in Annapolis, Maryland. The site, named the St. Mary's Site (18AP45) for the Catholic church on the property, is currently owned by the Redemptorists, a Roman Catholic congregation of priests and brothers who have occupied the site since 1852. Prior to the Redemptorists' tenure, the site was owned by the Carroll family from 1701-1852 and is perhaps best known as the home of Charles Carroll of Carrollton (1737-1832), signer of the Declaration of Independence. Excavations at the site were conducted during four consecutive summer seasons from 1987-1990. The investigation focused on three research questions. The first line of inquiry were questions surrounding the dating, architectural configuration, and artifact deposits of the "frame house," a structure adjoining the west wall of the brick Carroll House via a "passage" and later a three story addition. The frame house was partially demolished in the mid-nineteenth century but the construction was thought to pre-date the brick portion of the house. The second research question was spurred by documentary research which indicated that the property might have been the location of Proctor's Tavern, a late 17th-century tavern which served as the meeting place of the Maryland Provincial Assembly. Archaeological testing hoped to determine its location and, if found, investigate Annapolis' early Euro-American occupation. The third research question focused on the landscape of the site as it was shaped by its occupants over the past three hundred years. The research questions included investigating the stratigraphy, geometry, and architectural and planting features of Charles Carroll of Carrollton's terraced garden built during the 1770s, and investigating the changes to the landscape made by the Redemptorists in the nineteenth and twentieth centuries. While no structural evidence associated with Proctor’s Tavern was uncovered during limited excavations along Spa Creek, the historic shore of Spa Creek was identified, buried beneath deep fill deposits laid down during construction of the Carroll Garden. Features and deposits associated with this period likely remain intact in a waterlogged environment along the southeastern sea wall at the St. Mary’s Site. Evidence of extensive earth moving by Carroll is present in the garden and was identified during excavation and coring. This strongly suggests that the garden landscape visible at the St. Mary’s Site is the intact Carroll Garden, which survives beneath contemporary and late nineteenth century strata. The extant surviving garden should be considered highly sensitive to ground-disturbing activities, and is also highly significant considering demonstrable associations with the Carroll family. Other garden-related features were also discovered, including planting holes, and a brick pavilion or parapet located along Spa Creek to the south of the site. The Duke of Gloucester Street wall was shown to be associated with the Carroll occupation of the site. Finally, intensive archaeological research was directed at the vicinity of a frame house constructed and occupied by the Carrolls to the east of the existing brick house, which was replaced by the Redemptorists in the nineteenth century with a greenhouse. These superimposed buildings were documented in detail and remain highly significant features at the St. Mary’s Site.