321 |
The Studies of Risk Assessment of NanoparticlesLi, Han-Chieh 23 June 2006 (has links)
The study of this project includes nomenclature, methodologies for risk assessment, and the exchange of information on human and ecological toxicology studies in nanotechnology research. The goals are: (1) collecting domestic and international nanotechnology relevant to toxicity information, (2) establishing the flow chart of nanotechnology risk assessment, (3) making suggestions of methodologies for risk assessment on nanotechnology, and (4) establishing the structure of nanoparticles risk management for reference to future nanotechnology risk management.
Nanopartilces, quantum dots, fullerenes and carbon nanotubes has been collected in Toxicological information of nanomaterials. This study has established the Precautionary Principle and the preliminary framework for health risk assessment, which could prevent or reduce risks before the completed development of the potential danger, and reply the appeal for developing a standard methodology for risk assessment which is made by European Commission during the Brussels Conference of 2004.
Exchange of informations of nanotoxicology allows contact between domestic and international researchers. The methodologies for risk assessment establishes framework for health assessment of risks which could be used to be the direction to develop the internal risks assessment, and is advantageous to the government in management of the risks of nanotechnology.
|
322 |
The stock risk and return analysis of failure firmsChiang, Yi-Chang 17 June 2000 (has links)
This study examines the failure firm¡¦s stock risk character and return behavior prior announcements day. This study includes three parts. First, we examine the risk different between failure firms and control firms. Second, we analysis the returns character of failure firms, and third, we test whether the different judgment announcements will affect the failure firms¡¦ stock return.
We examine the daily stock returns between 1997 and 1999, 26 failure firms and 50 control firms have been observed. The empirical results can be summarized as follows:
1. Systematic risk behaves quite differently for the failure and control groups as much as two years before failure.
2. Both the total variance and the firm-specific variance behave quite differently for the failure and control groups only two months before failure.
3. The market is effective before announcements and not effective after announcements.
4. The shareholders of failure firms lost between different judgment announcements are no different in a short time.
5. The magnitude of the price reaction to failure filings depend on the probability of bankruptcy and proxy for predisclosure information impounded in stock prices over the year prior to failure filing.
|
323 |
noneSu, Wen-Hui 08 June 2001 (has links)
none
|
324 |
noneOu, Yu-Chen 23 January 2002 (has links)
none
|
325 |
Risk assessment of runoff on a range watershed in Brazos County, TexasGwaltney, Tracy Marie 30 September 2004 (has links)
A drip type rainfall simulator and an existing watershed study were used to assess relationships between runoff, infiltration, erosion and associated risk thresholds on a range watershed in Brazos County, Texas. The focus of the research was determining erosion risk associated with seasonal variations in precipitation and vegetation. The objectives were to (1) develop a climatic profile for Brazos County, Texas, (2) evaluate relationships between vegetative cover, infiltration, runoff, and climatic events, (3) quantify erosion/ runoff risk associated with measured vegetation, soil moisture, and climatic events, and (4) identify potential managerial thresholds for erosion risk management on similar range watersheds. The current year climatic profile showed the wettest season was summer with thirty-two percent of the precipitation coming from one rainfall event. Also, October through December was higher than the long-term rainfall average. Pair wise correlations identified season, initial time to runoff, percent litter, annual as the dominant species, soil moisture, amount to runoff and amount to storage as significant (p<0.05) variables affecting runoff and infiltration. Percent saturation and annuals as the dominant species were significant variables affecting sediment yield. During the current study, seasonal variations in precipitation patterns influenced runoff, infiltration, and sediment yield. Spring and summer had the highest infiltration rates while the largest runoff events were in fall and winter. The highest percent of soil saturation coincided with the largest runoff and sediment losses.
Minimums of two centimeters (winter and fall) and three centimeters (spring and summer) initiated runoff. This rainfall threshold would be exceeded 20 percent of the time based on the climatic profile developed for Brazos County. Peak biomass production for the watershed site was 170.61 g/m2. This was above the recommended biomass threshold of 134.5 to 168.1 grams/m2 to minimize sediment loss for tallgrass rangeland. Annual sediment loss was 10.8 grams/m2, which is negligible. Additional research across a wider array of site variation is needed to identify appropriate thresholds for the Post Oak Savanna ecosystem.
|
326 |
Risk assessment of surface vs subsea blowout preventers (bops) on mobile offshore drilling units focusing on riser failure and the use of subsea shear ramsMelendez, Jorge Luis 16 August 2006 (has links)
The use of a slim, high-pressure drilling riser for surface blowout preventer operations in the deepwater Gulf of Mexico was assessed as an alternative to conventional drilling procedures from floating units. Comparison of the low- and high-pressure system was accomplished through a detailed qualitative (assigned frequency) and quantitative (reported incidents) risk analysis using generic fault tree models to statistically determine the reliability of the system based on metocean conditions from the Gulf of Mexico. It is hoped that this investigation will serve as a starting point for drilling companies and regulatory agencies to understand the risk of implementing a high-pressure riser for surface blowout preventer applications in the Gulf of Mexico, because specific failure events and conditions of the area were considered. Despite the generic description of the drilling riser and pressure control system, the models are flexible enough to be modified and adapted to a specific rig configuration and location. Results from the qualitative comparison suggest an acceptable risk and high reliability for high-pressure riser systems and surface preventers. The quantitative portion of the study is influenced by the data quality of the high-pressure system, however it provides a range of possible reliability values with an acceptable overall risk.
|
327 |
Assessment of suspended dust from pipe rattling operationsPark, Ju-Myon 30 October 2006 (has links)
Six types of aerosol samplers were evaluated experimentally in a test chamber
with polydisperse fly ash. The Andersen sampler overestimates the mass of small
particles due to particle bounce between stages and therefore provides a conservative
estimate of respirable particulate mass and thoracic particulate mass. The TSP sampler
provides an unbiased estimate of total particulate mass. TSP/CCM provides no
information below ESD 2 õm and therefore underestimates respirable particulate mass.
The PM10 sampler provides a reasonable estimate of the thoracic particulate fraction.
The RespiCon sampler provides an unbiased estimate of respirable, thoracic, and
inhalable fractions. DustTrak and SidePak monitors provide relative particle
concentrations instead of absolute concentrations because it could not be calibrated for
absolute particle concentrations with varying particle shape, composition, and density.
Six sampler technologies were used to evaluate airborne dust concentrations
released from oilfield pipe rattling operations. The task sampled was the removal of
scale deposited on the inner wall of the pipe before it was removed from service in a
producing well. The measured mass concentrations of the aerosol samplers show that a Gaussian
plume model is applicable to the data of pipe rattling operations for finding an
attainment area. It is estimated that workers who remain within 1 m of the machine
centerline and directly downwind have an 8-hour TWA exposure opportunity of (13.3 ñ
9.7) mg/m3 for the Mud Lake pipe scale and (11.4 ñ 9.7) mg/m3 for the Lake Sand pipe
scale at 95 % confidence. At distances more than 4 m downwind from the machine
centerline, dust concentrations are below the TWA-TLV of 10 mg/m3 for the worker in
both scales. At positions crosswind or upwind from the machine centerline there is no
measurable exposure. Available data suggest that the attainment area for the public
starts at about 9 m downwind from the machine centerline in both scales, as 24 hour
average concentrations at these distances are smaller than the 0.15 mg/m3, the NAAQS
for unrestricted public access. The PSD of the suspended plume is dominated by
particles smaller than ESD 50 õm.
|
328 |
Risks in the Swedish Forest, Paper & Packaging IndustryLundqvist, Stina, Peterson, Tove January 2008 (has links)
<p>Background: In today’s more challenging business environment companies operating in a global market are faced by uncountable numbers of risks. The foundation of this report is based on the scenario of risks within one of the most important industries for the Swedish economy, namely the Forest, Paper and Packaging (FPP)industry. Sweden is one of the most forested countries in Europe and despite being a small country Sweden alone stands for 7 percent of the world’s total FPP production. However, it has been argued that the FPP industry might be in the midst of change where several articles and reports have commented on the upcoming challenges within the industry.</p><p>Problem discussion & Purpose: Globalization, shifting economical paradigm, a rising interest for sustainability, increased raw material prices and tougher market conditions have in combination lead to a change in today’s view of how to handle risks. FPP companies have to deal with countless number of issues facing business today and the question of how to manage risks across organizations are becoming increasingly important. The purpose of this thesis is to identify risks faced by the Swedish FPP industry and thereafter assess the most crucial risks impact and likelihood of occurrence and how they are linked to the dilemma of holding forestland or not.</p><p>Method: This study has its origin in interprevitism along with the ontological assumptions of constuctionism. An abductive research approach has been applied that has features from both deduction and induction. The study has applied the three research strategies; descriptive, explanatory and exploratory study in order to produce a true representation, describe relationships and in the same time seek new insight into the researched phenomena. A qualitative research strategy was applied where several semi-structured interviews were carried out, with respondents selected through a purposive sample of the Swedish FPP industry. Thereafter complementary material was sent out in form of a self-administrative questionnaire regarding the identified risks and their significance.</p><p>Theoretical framework: Consist of general theories concerning macro environment and risk analysis theories for understanding industries along with previous reports concerning the FPP industry. In order to determent the nature and scale of the risk the Risk radar model will be applied along with an assessment of impact and likelihood of occurrence.</p><p>Conclusion: The Swedish FPP industry today faces the following risks; Globalization & Shift of Capital to the Emerging Markets, Overcapacity, Foreign Exchange Impact & Currency Risks, Export & Import Taxes, Raw Material, Energy & Transportation Costs, Sustainability & Increased Environmental Awareness and Climate Change & Unforeseen Events. Out of these risks the most crucial where proven to be Raw Material and Energy & Transportation Costs hence there high impact and likelihood of occurrence. Given the pros and cons of holding forestland in relation to the most crucial risks identified the ownership of forestland can be seen as a strategic way of educing the threat from these risks, turning them into opportunities.</p>
|
329 |
Kvinnliga och manliga egenföretagares riskbenägenhetBjäreborn, Lisa, Karlsson, Therese January 2008 (has links)
<p>Bakgrund: Förr var det ofta kvinnan som hade till uppgift att ta hand om hemmet, medan mannen var familjeförsörjare. Idag arbetar kvinnor och män i princip lika mycket utanför hemmet, men de befinner sig på olika delar av arbetsmarknaden. I tidigare forskning har man funnit att personer som är beredda att ta risker har en benägenhet att bli egenföretagare. Det finns flera undersökningar där forskare funnit könsskillnader när det handlar om risktagande. I vilken utsträckning dessa skillnader är bevis på att det verkligen finns allmänna könsskillnader i riskpreferens och att det inte bara beror på sociala och omvärldsfaktorer är ännu olöst.</p><p>Syfte: Syftet är att beskriva och förklara om det finns något samband mellan finansiellt risktagande och kön.</p><p>Avgränsningar: Vi har avgränsat oss till egenföretagare i Växjö kommun. Vi har endast inriktat oss på riskbenägenhet som har med respondenternas finansiella beslut i företaget att göra.</p><p>Metod: I uppsatsen har vi använt oss av ett positivistiskt synsätt och ett kvantitativt tillvägagångssätt. Det empiriska materialet har vi samlat in med hjälp av enkäter. Vi har sedan testat våra hypoteser och analyserat övriga variabler.</p><p>Slutsatser: I vissa beslutssituationer fann vi samband mellan kön och riskbenägenhet, och där visade det sig att kvinnorna tog mer risk än männen. Eftersom vi inte fann samband överallt beror riskbenägenhet snarare på beslutssituationen och hur beslutsfrågorna är formulerade än på kön.</p><p>Förslag till fortsatt forskning: Att undersöka hur risktagandet ser ut i en bransch. Det skulle vara intressant att intervjua några kvinnliga och manliga egenföretagare om vad de har för syn på sitt risktagande i den specifika branschen.</p>
|
330 |
Three essays on risk-adjusted customer lifetime value and returns to search /Singh, Shweta, January 2008 (has links)
Thesis (Ph.D.)--University of Texas at Dallas, 2008. / Includes vita. Includes bibliographical references (leaves 91-99)
|
Page generated in 0.0422 seconds