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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Will Oakland Burn Again: Understanding the Fire Hazard in an Urban Park System

Zambrano, Alessandra M 01 June 2021 (has links) (PDF)
Though almost thirty years have passed since the 1991 Tunnel Fire, the wildfire hazard is still present in the Oakland Hills. This study was conducted to determine if the vegetation in the Oakland Hills had reverted back to fuel conditions that contributed to the Tunnel Fire, examine how the fire hazard has changed since 1991, and evaluate planned wildfire mitigation. The goal was to determine how fuel conditions have changed since 1991 and compare potential fire behavior to that of the Tunnel Fire. Additionally, the study examined the effectiveness of the mitigation actions described in the East Bay Regional Park District’s Wildfire Hazard Reduction and Resource Management Plan on lowering extreme fire behavior. Through the use of remote sensing, historical aerial imagery, satellite imagery, and Landsat imagery the 1991 and 2018 fuel conditions were analyzed. ArcGIS Pro and FlamMap 6 were used to compare hectares of fuel and changed in fire behavior between the two year. Mitigation actions were modeled with FlamMap 6 and ArcGIS Pro and fire behavior was compared between untreated conditions and post treatment conditions. The vegetation in the Oakland Hills, in the absence of fire, returned to a mature state, similar to the 1991 conditions. However, there was a reduction in the overall hectares of fuel model 147 in 2018. Modeled fire behavior indicated an overall reduction in extreme fire behavior when comparing 1991 to 2018. This reduction varied on a park level with each park performing differently. When modeled, mitigation was able to lower extreme fire behavior across the landscape but success varied on an individual park basis. In conclusion, should ignition occur presently, under foehn wind conditions, a fire would still exhibit very extreme behavior with a high potential for catastrophic loss, and implantation of planned mitigation measures may be able to lower the degree of extreme fire behavior.
2

Thermal characteristics of grinding fluids

Massam, Mark January 2008 (has links)
High Efficiency Deep Grinding (HEDG) combines high depths of cut, high grinding wheel speeds with high work piece feed rates to deliver a very high stock removal process that can produce components free of surface damage. High contact temperatures are a characteristic of the process and this produces a mass of hot grinding sparks being ejected from the grinding zone. Neat oil cutting fluids are typically used in HEDG due to their excellent lubricity, but the high grinding wheel speeds employed leads to high levels of highly volatile cutting fluid mist in the machine canopy. This mist can mix with the hot grinding sparks being ejected from the grinding zone to create a potential fire hazard. The project aim was to produce a cutting fluid application strategy for the HEDG regime, focusing on establishing the thermal characteristics of cutting fluids in order to determine the optimum cutting fluid for the HEDG process. The cutting fluid application strategy also involved investigating the optimum means by which to apply the cutting fluid, based on minimising amount of cutting fluid used in the process and in reducing the potential fire hazard. The characteristics that have a thermal impact on the grinding process are the cooling, lubrication, ignition and misting properties of the fluid. A series of tests were established to investigate these properties and therefore allow different fluids to be compared and contrasted for their suitability for the HEDG regime based. Once an optimal cutting fluid had been established, the project then investigated the optimal method of applying this fluid, with particular reference to the type and design of the nozzle used to apply the fluid to the grinding zone. As part of these trials, a series of benchmark tests were also conducted using long established cutting fluid application techniques to enable the benefits of the new strategy to be evaluated. The project concluded that high viscosity neat oil ester based cutting fluids were the best fluids to be used in the HEDG regime due to they excellent lubricity and low misting properties coupled to their relatively high resistance to ignition when compared to neat mineral oils. The studies also found that using a high viscosity ester based fluid and then applying it using a coherent jet nozzle, significant reductions in the grinding powder and specific grinding energy could be achieved whilst significantly lowering the amount of mist in the machine, thus reducing the potential fire hazard and the volume of cutting fluid used by the process.
3

Assessing Surface Fuel Hazard in Coastal Conifer Forests through the Use of LiDAR Remote Sensing

Koulas, Christos 17 December 2013 (has links)
The research problem that this thesis seeks to examine is a method of predicting conventional fire hazards using data drawn from specific regions, namely the Sooke and Goldstream watershed regions in coastal British Columbia. This thesis investigates whether LiDAR data can be used to describe conventional forest stand fire hazard classes. Three objectives guided this thesis: to discuss the variables associated with fire hazard, specifically the distribution and makeup of fuel; to examine the relationship between derived LiDAR biometrics and forest attributes related to hazard assessment factors defined by the Capitol Regional District (CRD); and to assess the viability of the LiDAR biometric decision tree in the CRD based on current frameworks for use. The research method uses quantitative datasets to assess the optimal generalization of these types of fire hazard data through discriminant analysis. Findings illustrate significant LiDAR-derived data limitations, and reflect the literature in that flawed field application of data modelling techniques has led to a disconnect between the ways in which fire hazard models have been intended to be used by scholars and the ways in which they are used by those tasked with prevention of forest fires. It can be concluded that a significant tradeoff exists between computational requirements for wildfire simulation models and the algorithms commonly used by field teams to apply these models with remote sensing data, and that CRD forest management practices would need to change to incorporate a decision tree model in order to decrease risk. / Graduate / 0799 / 0478 / christos@koulas.ca
4

A probabilistic comparison of times to flashover in a compartment with wooden and non-combustible linings considering variable fuel loads

Studhalter, Jakob January 2012 (has links)
Prescriptive fire safety codes regulate the use of combustible room linings to reduce fire risk. These regulations are based on classification systems which designate materials according to their relative hazard when exposed to a standard fire scenario. However, no quantitative data sets on the fire risk of wooden lining materials exist which take into account relevant uncertainties, such as movable fuel loads in compartments. This work is a comparative risk analysis on the influence of wooden linings on the time to flashover in a compartment, considering uncertainties in the fuel load configuration. A risk model is set up for this purpose using B-RISK, a probabilistic fire design and research tool currently under development at BRANZ (Building Research Association of New Zealand) and the University of Canterbury. The risk model calculates fire spread in a compartment between fuel load items and from fuel load items to combustible linings. Multiple iterations are performed considering varying fuel load arrangements and input values sampled from distributions (Monte-Carlo simulation). The functionality and applicability of the risk model is demonstrated, comparing the model with experiments from the literature. The model assumptions are described in detail. Some of the model inputs are defined as distributions in order to account for uncertainty. Parametric studies are conducted in order to analyse the sensitivity of the results to input parameters which cannot be described as distributions. Probabilistic times to flashover are presented and discussed for an ISO 9705 compartment considering varying movable fuel loads and different lining configurations. The fuel load is typical for a hotel room occupancy. Effects of suppression measures are not considered. It is shown that flashover occurs approximately 60 seconds earlier if walls and ceiling are lined with wooden materials than if all linings are non-combustible. This value refers to the 5th percentiles of the time to flashover, i.e. in 5% of the cases flashover has occurred and in 95% of the cases flashover has not (yet) occurred. Referring to 50th percentiles (median values), the difference is approximately 180 seconds. Furthermore it is shown that with wooden wall and ceiling linings in approximately 95% of the iterations flashover occurs, whereas with non-combustible linings 86% of the iterations lead to flashover. After 900 seconds, in 90% of the iterations flashover occurs if walls and ceiling are lined with wooden materials, and in 77% of the iterations if the linings are non-combustible. Using different wooden lining materials (non-fire retardant plywood, fire retardant plywood, and MDF) has no significant effect on the probabilistic times to flashover. Varying the fuel load energy density has an influence only when all linings are non-combustible and when the fuel load energy density is relatively low (100–200 MJ/m2). This work contains recommendations regarding the further development of B-RISK, the research into the fire risk connected with wooden room linings, and suggestions regarding the further development of prescriptive fire safety codes.
5

Identification, examination and management of risk factors behind dwelling fires in the Kingdom of Saudi Arabia : a managerial and policy perspective

Al-Sharabi, Faisal January 2013 (has links)
Fire incidents are a central issue in Saudi civil defence. Despite detailed regulation concerning firefighting equipment dealing with dwelling fires, fires occur frequently. Globally, research on dwelling fire safety is relatively new. Most studies focus on human factors, incidence and causal issues. Few studies examine management or policy-making perspectives towards managing these individual agents. Thus, a detailed study on understanding the management of these factors for dwelling fires is long overdue. The study uses an inductive approach to investigate key management issues in reducing dwelling fires in Saudi Arabia. This qualitative study consisted of twelve indepth semi-structured interviews and four focus groups with senior managers of the Civil Defence Division dealing with fire safety. A sustainability-based framework is developed to map the critical issues in generating a long-term planning solution to policy and management of fire hazard and risk in Saudi Arabia. Critical drivers of this sustainability approach are good management, regulation, governance practices: especially accountability and transparency; reduction of tribalism, bureaucracy, and burns unit efficiency. However, given the modern environment of communications, information technology and communications, and in particular public education, are viewed as important mediators between drivers and sustainability. The critical role of knowledge generation is also positioned as a mediator. The framework proposed is a paradigm shift from merely managing fire incidents on a case by case basis to a proactive risk reduction strategy. This represents an original solution to managing fire hazards at a national level and an important contribution to the fire management literature.
6

Identification, Examination and Management of Risk Factors behind Dwelling Fires in the Kingdom of Saudi Arabia: A Managerial and Policy Perspective

Al-Sharabi, Faisal January 2013 (has links)
Fire incidents are a central issue in Saudi civil defence. Despite detailed regulation concerning firefighting equipment dealing with dwelling fires, fires occur frequently. Globally, research on dwelling fire safety is relatively new. Most studies focus on human factors, incidence and causal issues. Few studies examine management or policy-making perspectives towards managing these individual agents. Thus, a detailed study on understanding the management of these factors for dwelling fires is long overdue. The study uses an inductive approach to investigate key management issues in reducing dwelling fires in Saudi Arabia. This qualitative study consisted of twelve indepth semi-structured interviews and four focus groups with senior managers of the Civil Defence Division dealing with fire safety. A sustainability-based framework is developed to map the critical issues in generating a long-term planning solution to policy and management of fire hazard and risk in Saudi Arabia. Critical drivers of this sustainability approach are good management, regulation, governance practices: especially accountability and transparency; reduction of tribalism, bureaucracy, and burns unit efficiency. However, given the modern environment of communications, information technology and communications, and in particular public education, are viewed as important mediators between drivers and sustainability. The critical role of knowledge generation is also positioned as a mediator. The framework proposed is a paradigm shift from merely managing fire incidents on a case by case basis to a proactive risk reduction strategy. This represents an original solution to managing fire hazards at a national level and an important contribution to the fire management literature.
7

Restoring oak habitats in the Southern Willamette Valley, Oregon: A multi-objective tradeoffs analysis for landowners and managers

Ulrich, Nathan D., 1977- 12 1900 (has links)
xvii, 160 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Restoring oak habitats is an emerging conservation priority in Oregon's Willamette Valley. Both private and public landowners face multiple challenges to conservation and restoration of oak habitats, including a lack of knowledge about the potential tradeoffs and constraints for achieving multiple priorities on a given site. This study simulated 25 alternative oak habitat restoration scenarios to develop estimates of outcomes related to six different restoration priorities: costs, income potential, habitat value, scenic quality, fire hazard reduction potential, and time requirements. Model results indicated that initial land conditions strongly influence a landowner's ability to optimize among these different priorities. To assist landowners with decision-making, model estimates were organized into a digital decision matrix that communicates advantages and tradeoffs associated with each alternative scenario. In doing so, it aims to help landowners choose restoration goals that better meet their broader needs and objectives. / Committee in Charge: Dr. Bart Johnson, Chair; Dr. Robert Ribe

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