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No description available.

No description available.

No description available.

No description available.

Larvae of Ae. triseriatus mosquitoes were collected from treeholes on the Ball State University campus. These insects were raised to adulthood under laboratory conditions. Newly hatched larvae were raised in deionized water. One hundred twenty-five of instar 1 mosquitoes (group A) were placed into separate baby food jars containing deionized water. These jars were separated into five groups. The pH of the water in each group was adjusted to 3, 4, 5, 6 and 7 with a 70% to 30% sulfuric-nitric acid solution. Subsequent groups consisting of instar 2, 3 and 4 larvae and pupae (groups B, C, D and E respectively) were exposed to the same experimental treatment as that of group A. The effects of each of these pH levels on mortality and development was observed until the insects reached maturity or died.Larvae in water of pH 3 experienced a higher percentage of mortality than mosquitoes exposed to less acidic solutions. A decrease in mortality with age was observed. Mortality of insects in group A was greater than that of any other group. Mosquitoes in group D experienced the lowest mortality.Variations of developmental time for mosquitoes in pH 3 were probably due to high mortality. Developmental time was similar for all groups. Slight variations between these groups may have been due to natural fluctuations in development. The total average developmental time for Ae. triseriatus mosquitoes of this study was 11.12 days.

No description available.

No description available.

The harmful effects of air pollutants on human beings and environment have been the major reason for efforts in sampling, analysis and control of their sources. The major pollutants emitted to atmosphere from stationary combustion processes are nitrogen oxides, inorganic acids, carbon dioxide, carbon monoxide, hydrocarbon and soot. In the current work two methods are developed for sampling and analysis of volatile chlorinated aromatic hydrocarbons and semi-volatile chlorinated aromatic hydrocarbons for example 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) by using solid sorbent, thermal desorption and high resolution GC-MS. The capacity of several solid sorbents is compared by breakthrough value and percentage recovery ofthe analyte from the sorbent. The thermal stability of polyvinyl chloride (PVC) and PVC in the presence of metals is studied because PVC is a polymer commonly found in solid waste derived from medical waste, car recycling and electrical cable. Harmful pollutant emissions from combustion and pyrolysis of PVC are measured using the novel method developed in this work. The main inorganic volatile is HCl while benzene is the major volatile organic formed under pyrolysis and combustion conditions. The thermal degradation of PVC produces a large number of chlorinated aromatic hydrocarbon, aromatic hydrocarbon and short chain linear gases. A study is designed for control of harmful pollutants from combustion of PVC including HCl, aromatic hydrocarbon, chlorinated aromatic hydrocarbons and soot. It is reported that the presence of metal oxides have the ability to control the level of harmful emissions by facilitating the producing of more short chain linear gases. A study is designed for control of harmful pollutants from combustion of PVC including HCl, aromatic hydrocarbon, chlorinated aromatic hydrocarbons and soot. It is reported that the presence of metal oxides have the ability to control the level of harmful emissions by facilitating the producing of more short chain linear gases. Two methods are developed for the control of soot from liquid and gas combustion process by using applied fields, Magnetic and electric fields. In this study, it is shown that an increase in applied field strength leads to an increase in flame temperature but a decrease in the length of flame. The level of soot emission was decreased in presence of an applied field. A discussion of the effect of applied fields on the combustion process is given.

Emission limits for diesel engine exhaust pollutants are being continually reduced in line with increasingly stringent emissions legislation. Essential to the task of reducing diesel exhaust emissions is an understanding of the origin of the exhaust pollutants. This research has investigated the origin of a group of compounds, polycyclic aromatic hydrocarbons (PAH), in diesel exhaust emissions using 14C-radiotracer techniques developed specifically to investigate the origin of the organic components in diesel emissions. The use of radiotracers in this research has enabled both the extent to which individual PAH survive combustion and the extent to which PAH are pyrosynthesized during combustion to be measured accurately. No other diesel emissions research technique has yielded information which is so unequivocal. Radio-chromatographic techniques were developed specifically for the identification and quantification of radioactive species present in diesel emissions resulting from the combustion of a single 14C-radiolabelled precursor. Radio-high performance liquid chromatography (radio-HPLC) was the main technique used and was applicable as both a tool for sample fractionation and for analytical measurement. Radio-gas chromatographic techniques (radio-GC) were also developed and applied to the identification of radioactive species in the exhaust emissions. Diesel exhaust samples were collected from a 2L direct injection Perkins Prima diesel engine using a novel exhaust sampling device, the Total Exhaust Solvent Stripping Apparatus (TESSA) devised previously to sample organic species from automobile exhausts. Diesel combustion experiments were performed on three 14C-radiolabelled PAH, fluorene, pyrene and benzo[α]pyrene (B[α]P), and 14C-n-hexadecane. These were spiked into the diesel fuel and were combusted in the Prima Engine. The extent of survival was 0.04% for B[α]P, 0.17% for pyrene and 0.87% for fluorene. The amount of each PAH in the exhaust emissions derived from pyrosynthetic sources ranged from <20% for B[α]P, to 26.5% for fluorene and 71% for pyrene. The extent to which individual PAH survive the diesel combustion process was correlated with the molecular orbital distribution of the molecule, and especially the energy levels of the lowest unoccupied molecular orbital (LUMO). It is concluded that the relationship between PAH survival and PAH molecular orbitals (MOs) is owing to the kinetics of combustion reactions and the chemical reactivity of the P AH. The extent to which individual PAH molecules are formed during combustion varies considerably. From the limited number of experiments performed in the current research it has not been possible to determine the mechanisms responsible for the formation of these PAH during combustion. Mass balance calculations have demonstrated that the degree of pyrosynthesis of the parent PAH molecules investigated in this research may be accounted for by comparatively low rates of dealkylation of alkyl-substituted derivatives present in diesel fuel. The importance of dealkylation reactions during diesel combustion, was investigated by combusting a low aromatic fuel spiked with a non-radiolabelled alkyl-PAH, 2- and 3-ethylphenanthrene (2- and 3-EtPa), which were synthesized for this purpose. The 2 and 3-EtPa isomers were recovered in yields of 0.35% and 0.3% respectively. No dealkylation of the EtPa was detected. A statistically significant increase in the emissions of 3-methylphenanthrene (3-MePa) was detected and was equivalent to a conversion rate of 0.0004% of the EtPa spike. It is proposed that the ease with which individual alkyl-PAH isomers are dealkylated varies for specific isomers, and is dependent on the position of the alkyl-substituent on the aromatic nucleus. The major product from the combustion of the EtPa was vinylphenanthrene (ViPa) which produced in a yield equivalent to a conversion of 0.01% of the EtPa spike. Radiotracer experiments with 14C-n-hexadecane were performed to investigate the origin of the aliphatic component of diesel emissions. The extent of hexadecane survival was 0.35%. Approximately two thirds of the hexadecane in the emissions was derived from pyrosynthetic sources. The most probable source of the pyrosynthesized hexadecane in the emissions was 'thermal cracking of higher molecular weight aliphatic species in diesel fuel during the combustion process. This process may account for a significant proportion of lower molecular weight n-alkanes emitted in diesel emissions.