Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Chemical Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaves 123-126. / M.S.

Thesis (MBA.) --University of Limpopo, 2008 / Chemicals are found to be enormously dangerous on the health and safety criteria. In academic laboratories, chemical safety has always been a major concern. Safety risks are either not perceived at all, or perceived to be less dangerous than what they actually are. The climate of safety in any organization consists of employees’ attitudes towards, and perceptions of safety behaviour. In academic departments, safety is influenced by factors such as the organisational environment, management attitude and commitment, the nature of the job or task, and the personal attributes of the individual. This study is concerned with safety climate and chemical management practices in academic departments. More specifically, it investigates the safety perceptions, attitudes, and chemical management behaviours of university employees. It represents the empirical results of a questionnaire survey administered in a university department and direct observations of safe and unsafe chemical management behaviours, targeting employees who work with chemicals. Based upon the survey analysis results, this study demonstrates that employees in the academic departments under study have a good degree of risk awareness and a relatively high degree of safety consciousness. The results also reveal employees’ intentional unsafe chemical management behaviours. Further, it was found, empirically, that overall employees’ intentional unsafe behaviours seem to be best explained by employees’ perceptions of management attitude and commitment to safety, social and physical work environment, priority for safety, as well as their perception of the risk they are generally exposed to in their work environment. The study, thus, establishes that perceptions of management attitudes and actions have a direct effect on employees’ behaviour. There is a positive correlation between workers’ safety climate and chemical management safe behaviour in academic departments.

Exposure to air contaminants is significantly associated with both short-term and long-term health effects. However, the precise mechanisms that derive such effects are not always understood. While an extensive background database from in vivo toxicological studies have been developed, most toxicity data is from oral and dermal chemical exposures rather than inhalation exposure. There is a need to explore new alternative approaches to provide toxicity information particularly on this technically demanding area. This research explores the potential of in vitro methods for toxicity assessment of workplace air contaminants. A tiered approach for in vitro toxicity testing of workplace contaminants was designed in which appropriate air sampling and exposure techniques were developed. A diversified battery of in vitro assays including the MTS (tetrazolium salt, Promega), NRU (neutral red uptake, Sigma) and ATP (adenosine triphosphate, Promega) and a multiple human cell system including: A549- lung derived cells; HepG2-liver derived cells, and skin fibroblasts were used. Primarily the application and merits of in vitro methods for prediction of toxicity of selected workplace contaminants including Ammonium hydroxide, Cadmium chloride, Cobalt chloride, Formaldehyde, Glutaraldehyde, Manganese chloride, Mercuric chloride, Sodium dichromate, Sulphureous acid and Zinc chloride was confirmed. To study the toxicity of airborne contaminants an indirect exposure method was established using air sampling techniques followed by static and dynamic direct exposure methods by culturing cells on porous membranes to reveal representative data relating to human airborne exposures. The static method enabled the measurement of an airborne IC50 (50% inhibitory concentration) value for selected volatile organic compounds (VOCs) including: Xylene (IC50 = 5,350-8,200 ppm) and Toluene (IC50 = 10,500- 16,600 ppm) after 1 hr exposure. By implementing the dynamic method, airborne IC50 values were calculated for gaseous contaminants including: NO2 (IC50 = 11 ?? 3.54 ppm; NRU), SO2 (IC50 = 48 ?? 2.83 ppm; ATP) and NH3 (IC50 = 199 ?? 1.41 ppm; MTS). A higher sensitivity of in vitro methods was observed compared to in vivo published data. A range of in vitro bioassays in conjunction with exposure techniques developed in this thesis may provide an advanced technology for a comprehensive risk assessment of workplace air contaminants.

Exposure to air contaminants is significantly associated with both short-term and long-term health effects. However, the precise mechanisms that derive such effects are not always understood. While an extensive background database from in vivo toxicological studies have been developed, most toxicity data is from oral and dermal chemical exposures rather than inhalation exposure. There is a need to explore new alternative approaches to provide toxicity information particularly on this technically demanding area. This research explores the potential of in vitro methods for toxicity assessment of workplace air contaminants. A tiered approach for in vitro toxicity testing of workplace contaminants was designed in which appropriate air sampling and exposure techniques were developed. A diversified battery of in vitro assays including the MTS (tetrazolium salt, Promega), NRU (neutral red uptake, Sigma) and ATP (adenosine triphosphate, Promega) and a multiple human cell system including: A549- lung derived cells; HepG2-liver derived cells, and skin fibroblasts were used. Primarily the application and merits of in vitro methods for prediction of toxicity of selected workplace contaminants including Ammonium hydroxide, Cadmium chloride, Cobalt chloride, Formaldehyde, Glutaraldehyde, Manganese chloride, Mercuric chloride, Sodium dichromate, Sulphureous acid and Zinc chloride was confirmed. To study the toxicity of airborne contaminants an indirect exposure method was established using air sampling techniques followed by static and dynamic direct exposure methods by culturing cells on porous membranes to reveal representative data relating to human airborne exposures. The static method enabled the measurement of an airborne IC50 (50% inhibitory concentration) value for selected volatile organic compounds (VOCs) including: Xylene (IC50 = 5,350-8,200 ppm) and Toluene (IC50 = 10,500- 16,600 ppm) after 1 hr exposure. By implementing the dynamic method, airborne IC50 values were calculated for gaseous contaminants including: NO2 (IC50 = 11 ?? 3.54 ppm; NRU), SO2 (IC50 = 48 ?? 2.83 ppm; ATP) and NH3 (IC50 = 199 ?? 1.41 ppm; MTS). A higher sensitivity of in vitro methods was observed compared to in vivo published data. A range of in vitro bioassays in conjunction with exposure techniques developed in this thesis may provide an advanced technology for a comprehensive risk assessment of workplace air contaminants.

This thesis research tested the utility of a quantitative measure of idea progression (B₁) in a computer-based training environment. Anderson (1971) only studied the different levels of the metric by simply rearranging sentences. In this experiment, however, careful rephrasing of a text created three statistically different training programs with B₁ averages of 0.31, 0.39, and 0.48 from instructional design, human-computer interaction, and human information processing guidelines. Three groups of industrial subjects (η = 8) were trained and tested to see which level maximizes worker comprehension of the chemical hazard concepts found in the Occupational Safety and Health Administration’s (OSHA) Material Safety Data Sheet (MSDS) Form 174. It was expected that subjects who received medium levels of complexity would show the highest post-test scores; however, no significant differences were detected (p>0.05). The negative results and corresponding small effect size are discussed along with future research suggestions. / Master of Science

This work seeks to develop new solvents for environmentally benign chemical synthesis. Switchable solvents are a new class of compounds that change properties upon the application of some stimulus such as heat, UV light, or pH. We have developed the use of a new solvent, thiirane oxide, that has chemical properties similar to DMSO. Thiirane oxide, however, undergoes facile decomposition to two gases at temperatures above 100 C, which is much lower than the temperature required for removing DMSO. Thus we have a solvent with excellent solvation properties, but with a built-in switch for easier removal. However, thiirane oxide leaves behind sulfurous products which make the reverse reaction to reform the solvent unfeasible. We are also developing the use of another solvent, piperylene sulfone, which is expected to have good solvent properties, yet with decomposition products that can be reacted to reform the solvent. This thesis also details the work to date on piperylene sulfone. Gas-expanded liquids (GXLs) also show promise as a new reaction medium. In order to design solvent systems that take full advantage of this medium, we desire to understand the microstructure of these fluids. To that end, we are using cage reactions to probe solute-solvent and solvent-solvent interactions at the molecular level. This thesis discusses the current research on using cage reactions to probe the structure of GXLs.

Background: The aim of this study was to investigate the use and management of hazardous chemical substances (HCS) at a chemistry department in a selected Higher Education Institution in Gauteng province. Method: A quantitative, baseline descriptive study was conducted using a structured survey checklist. The population consisted of the chemistry department. Other than purposive observation by the researcher, employees present during data collection were approached for further clarifying comment to survey questions. Results: It emerged that physical-, health- and environmental hazard classes of HCS were present; and that hazard types included flammable liquids, HCS with acute toxicity and carcinogenicity. Selected exposure control measures were lacking which created risks of fire and explosion. Conclusion: The study reflected the use and management of HCS, the actual and potential human exposure and the exposure control measures. Varying degrees of compliance were found, which, if attended to, should mitigate risks to health and safety. / Health Studies / M.A. (Nursing Science)

Background: The aim of this study was to investigate the use and management of hazardous chemical substances (HCS) at a chemistry department in a selected Higher Education Institution in Gauteng province. Method: A quantitative, baseline descriptive study was conducted using a structured survey checklist. The population consisted of the chemistry department. Other than purposive observation by the researcher, employees present during data collection were approached for further clarifying comment to survey questions. Results: It emerged that physical-, health- and environmental hazard classes of HCS were present; and that hazard types included flammable liquids, HCS with acute toxicity and carcinogenicity. Selected exposure control measures were lacking which created risks of fire and explosion. Conclusion: The study reflected the use and management of HCS, the actual and potential human exposure and the exposure control measures. Varying degrees of compliance were found, which, if attended to, should mitigate risks to health and safety. / Health Studies / M.A. (Nursing Science)

Indiana University-Purdue University Indianapolis (IUPUI) / Heat generation is a major safety concern in the design and development of Li ion batteries (LIBs) for large scale applications, such as electric vehicles. The total heat generation in LIBs includes entropic heat, enthalpy, reaction heat, and heat of mixing. The main objective of this study is to investigate the influence of heat of mixing on the LIBs and to understand whether it is necessary to consider the heat of mixing during the design and development of LIBs. In the previous research, Thomas and Newman derived methods to compute heat of mixing in LIB cells. Their results show that the heat of mixing cannot be neglected in comparison with the other heat sources at 2 C rate. In this study, the heat of mixing in different materials, porosity, particle sizes, and charging/discharging rate was investigated. A COMSOL mathematical model was built to simulate the heat generation of LIBs. The LIB model was based on Newman’s model. LiMn2O4 and LiCoO2 were applied as the cathode materials, and LiC6 was applied as the anode material. The results of heat of mixing were compared with the other heat sources to investigate the weight of heat of mixing in the total heat generation. The heat of mixing in cathode is smaller than the heat of mixing in anode, because of the diffusivity of LiCoO2 is 1 ×10-13 m2/s, which is larger than LiC6's diffusivity 2.52 × 10-14 m2/s. In the comparison, the heat of mixing is not as much as the irreversible heat and reversible heat, but it still cannot be neglected. Finally, a special situation will be discussed, which is the heat of mixing under the relaxation status. For instance, after the drivers turn off their vehicles, the entropy, ix enthalpy and reaction heat in LIBs will stop generating, but the heat will still be generated due to the release of heat of mixing. Therefore, it is meaningful to investigate to see if this process has significant influence on the safety and cycle life of LIBs.