This study was conducted to investigate the capacity of Cynodon nlemfuensis (star grass) to accumulate lead (Pb) and cadmium (Cd) and develop metal uptake models for sandy soils receiving treated sewage from domestic and industrial sources. The study area comprised a non-polluted area and an adjacent area that received treated sewage from Harare’s Firle Wastewater Treatment Plant for over 30 years. Measured soil properties, total Pb and Cd in soils and grass and past records of Pb and Cd in treated sewage were analysed. Growing grass in a greenhouse in pots with previously non-polluted soils amended by single and mixed Pb and Cd salts and irrigated with treated sewage tested the uptake capacity of star grass. Yields, soil bio-available and grass Pb and Cd levels were measured and used to develop models for estimating critical soil and grass concentrations at which productivity declines. In the field, star grass grown in 10m x 10m plots in the non-irrigated and irrigated areas, received varying amounts of treated sewage over 11 months. Soil bio-available and grass metal contents were measured and used to develop field-based models to predict Pb and Cd content in star grass. Star grass had a high Pb and Cd extraction capacity, making it unsuitable for pasture if grown on polluted soils. Correlation between total Pb and Cd in soils and grass was insignificant (p<0.05). Logarithm-based models of log10 bio-available soil levels and log10 grass metal levels provided the best-fit regression models for Pb and Cd predictions in grass. Toxicity levels of Pb and Cd that were derived for star grass from pot-based models were higher than levels recommended for pasture. Toxicity occurred without visible signs on grass, making it difficult to recognise toxicity without testing. The field-based uptake models predicted safe bio-available limits for pasture on sandy soils. The co-presence of Pb and Cd resulted in increased Cd uptake but did not significantly affect Pb uptake. Star grass can accumulate more than 1 mg/kg of Cd at total soil Cd levels of less than 1 mg/kg, suggesting that the soil limit may be too high for a sandy soil. / Thesis (PhD (Chemical Engineering))--University of Pretoria, 2007. / Chemical Engineering / unrestricted

En el año 2017, Perú sufrió el fenómeno del Niño Costero luego de 19 años. Este desastre afectó principalmente la costa norte del país, ocasionando que numerosas viviendas e instalaciones terminaran enterradas por las inundaciones. Además, varios puentes colapsaron causando que pueblos queden incomunicados. A raíz de ello, se puede determinar que no todos los puentes están preparados para este tipo de fenómenos, teniendo como posibles causas estudios de suelos y diseños estructurales con escasa información. Por tales motivos, la presente tesis se refiere al diseño y determinación del tipo de pilote para la cimentación profunda más eficiente en puentes sobre suelos arenosos en Tumbes mediante un modelo computarizado. La aplicación se realizará en el puente Canoas, en el cual se buscará optimizar el rendimiento de ejecución considerando que pueda soportar las cargas actuantes y las características del suelo. Se propondrá un diseño alternativo para la superestructura que junto con una cimentación profunda con pilotes analizados será un proyecto óptimo tiempo de construcción, sin descuidar la capacidad resistente y costo. Esta propuesta consta de un puente de 50m de luz con vigas metálicas que presenta estribos de 16 m de altura en cada apoyo. Estos estribos tienen un encepado con 12 pilotes cada uno tipo CPI-8 con barrena de hélice continua (CFA). El diseño de la superestructura se realizará en SAP2000, los estribos serán en GEO5 y los pilotes se diseñarán por dos métodos (FHWA 1999 y analítico) comprobando su resistencia grupal con la eficiencia del grupo de 12 pilotes. / In 2017, Peru suffered the phenomenon of the Coastal Child after 19 years. This disaster mainly hit the north coast of the country, causing numerous homes and facilities to end up buried by flooding. In addition, several bridges collapsed causing villages to go intocommunicado. As a result, it can be determined that not all bridges are prepared for this type of phenomenon, taking as possible causes soil studies and structural designs with little information. For these reasons, this thesis refers to the design and determination of the type of pilot for the most efficient deep foundation in bridges on sandy soils in Tumbes using a computerized model. The application will be carried out on the Canoas bridge, in which it will be sought to optimize the execution performance considering that it can withstand the actuating loads and characteristics of the ground. An alternative design will be proposed for the superstructure that together with a deep foundation with analyzed piles will be an optimal construction time project, without neglecting the resilient capacity and cost. This proposal consists of a 50m light bridge with metal beams that presents 16 m high stirrups in each support. These stirrups have a brush with 12 piles each type CPI-8 with continuous propeller auger (CFA). The superstructure design will be done in SAP2000, the stirrups will be in GEO5 and the piles will be designed by two methods (FHWA 1999 and analytical) checking their group resistance with the efficiency of the group of 12 piles. / Tesis

In this thesis work, I examine the use and adoption of online communication media by 840 fire and police departments that were affected by the 2012 Hurricane Sandy. I began by exploring how and why these fire and police departments used (or did not use) online media to communicate with the public during Hurricane Sandy. Results show that fire and police departments used online media during Hurricane Sandy to give timely and relevant information to the public about things such as evacuations, damages, weather, and cleanup and to engage in two-way communications with their constituents. In their messages, fire and police departments sought to make the information provided more credible by referencing, rebroadcasting, and recommending other authoritative entities. Though some departments saw online media as a useful and effective means of communication with members of the public, other departments found them difficult to use given the challenging circumstances of Hurricane Sandy such as flooding and power outages. Next, I explore how a large-scale disaster event like Hurricane Sandy affects online media adoption by affected fire and police departments. I found an increase in online activity over Facebook, Twitter, and Nixle by the affected fire and police departments compared to before Hurricane Sandy. However, it is unclear whether this increase in online activity can be attributed to Hurricane Sandy or a natural increase over time.

No description available.

M.S.

No / There is an increasing interest in the use of Ground Source Heat Pumps (GSHPs) as a source of renewable energy in temperate countries. GSHPs coupled with buried heat collectors can harness the thermal energy from near-surface soils to provide the heating required for domestic properties. The performance of a GSHP system depends greatly on the thermal conductivity of the surrounding soils. Near-surface soils undergo cycles of drying and wetting due to, for example, the infiltration of rain water and/or fluctuations of the ground water table. Several parameters - including the properties of soil, suction head and saturation history - affect the thermal properties as well as the retention and flow of water. This paper presents results from a comprehensive laboratory investigation on sand samples with markedly different grain size distribution. Simultaneous measurements of thermal and hydraulic properties of the sands were taken under incremental increase/decrease in the suction head values to simulate cycles of drying and wetting. The results clearly suggest that the thermal conductivity is better expressed as a function of the matric suction head so as to reflect the saturation history. There has been almost five-fold increase in the measured value of thermal conductivity when the soil was wetted to a residual degree of saturation from being dry.

Six plots on the McMaster University campus were instrumented with thermocouples down to a depth of 225 cm. The choice of instruments and procedures was outlined and justified. A complete description of the site soil and climatic characteristics was made. Throughout the year soil temperature observations were taken to provide a complete picture of the conditions prevailing. In addition to studying the annual march of temperature, experiments were conducted by applying simple surface treatments to test plots and comparing the results with an untreated control plot. These experiments were conducted both over a period of weeks and on the daily scale. / Thesis / Candidate in Philosophy

Following the removal of Marmot Dam on the Sandy River, Oregon, several Lidar flights were flown over the area of the former reservoir. The resultant sequential DEMs permitted calculation of reach-scale volumetric erosion and aggradation following dam removal. This allows for change detection across the entire affected reach of the former impoundment rather than just at several cross sections. In the first year there was a net loss of blank sediment in the dewatered reach. Subsequent flights show continued degradation of 145,649 m3 as well as aggradation of 6,232 m3. Sediment transport reached quasi-equilibrium in 2012 with a net change of 65 m3. In addition, this technique allows the extraction of cross-section information which shows that the channel continues to be actively migrating in some areas while also being constrained by bedrock features from past volcanism in some reaches. This study further shows the capability of lidar to measure rates of aggradation and degradation for an entire river system instead of reach specific extrapolations and that repeat lidar flights can more than adequately assess the changing nature of entire stream reaches more rapidly and more cost effectively than traditional field techniques. In addition: The utility of Lidar to do river management with repeat returns, having successive lidar acquisitions run on the watershed level will help us to gain insight into the correlation to precipitation events and geomorphological change in a given reach. Lidar can be used to assess the validity of channel evolution models. Sequential runs of lidar can be used to adjust the overall effectiveness of current CEM's and create new ones that consider reach specific geomorphology. Dam removal projects should incorporate initial lidar flights prior to removal and follow acquisitions based on known CEM's for the region and overall region-specific physiography. Sequential lidar should be used for hazard mitigation and geohazards analysis with an acquisition timeframe that is appropriate for the region's physiography, geology, geomorphology and the return interval of the hazard being monitored.

More guns-less violence? A qualitative and comparative analysis between the swedish and the american daily news-press.

Within risk communication, much is understood about pre-event warning related to evacuation and sheltering; however risk communication during the return-entry phase when ending evacuations has been largely under-studied in the disaster literature. Understanding of the return-entry risk communication process is important because returning early or prior to issuance of the all-clear message can make returnees susceptible to post-disaster risks, and also hamper post-disaster activities such as debris removal, traffic management, utility restoration and damage assessments. Guided by the Warning Components Framework and the Theory of Motivated Information Management, this dissertation focuses on risk communication as it pertains to organizational behavior during the return-entry process by examining how local emergency management organizations develop, disseminate and monitor return-entry messages. The data is collected through semi-structured telephone interviews with local emergency management organizations that managed return-entry following Hurricane Sandy. The findings of the study indicate that local emergency management organizations required information on post-disaster threats, damages, and utility and infrastructure condition in order to develop return-entry strategy for their community. Organizations improvised to their existing risk communication measures by adopting creative ways for information dissemination to the evacuees. They also utilized active and passive approach to monitor public response to the return-entry messages.