The subject of this thesis is divided into two parts: (1) Treatment of 2-ethyl hexanol (2-EH) in an air stream by a pilot-scale biotrickling filter, and (2) Treatment of gaseous VOC emissions from a resin manufacturing plant by a full-scale biotrickling filter. Treatment of 2-Ethyl Hexanol in An Air Stream by A Pilot-Scale Biotrickling Filter 2-Ethyl Hexanol (2-EH) may release from the thermal breakdown of di-isooctyl phthalate (DOP), a commonly-used plasticizer, in the curing stage when manufacturing PVC synthetic leather and gloves. This paper reports the results of studies using a biotrickling filter (BTF) with blast-furnace slag packings (sizes = 2-4 cm and specific surface area = 120 m2/m3) for treatment of 2-EH in an air stream. The experimental setup consisted of a set of two-stage-in-series biotrickling filters. Each stage of the biotrickling filter was constructed from a 19.5-cm x 200-cm (ID x H) acrylic column packed with slags of 125 cm in height. The operation started with the conditions of recirculation liquid pH = 8.0 and rate (VL) = 8.83 m3/m2.h, a steady nutrient (ammonia nitrogen and phosphate phosphorus) addition, and without a special microbial seeding. Results indicate that, yellowish-brown biofilms on the surface of packing slags could be observed in one week and well developed in two weeks after the start-up operation. The effects of volumetric 2-EH loading (L) and superficial gas velocity (U0) on the 2-EH elimination capacity (K) and the removal efficiency (K/L) were tested. Long-term experimental results show that, in the conditions of influent 2-EH concentration C0 = 250 mg/m3, U0 = 162 m3/m2.h, and gas empty-bed-retention time EBRT = 55 s, K/L could be correlated by the equation K/L = 71.9/(72.4+L) with a correlation coefficient (R) of 0.9988. The 2-EH elimination rate was mass-transfer controlled when L<16 g/m3.h and reaction-controlled when L>16 g/m3.h. Results also indicate that nutrient addition and liquid recirculation were important for the normal operation of the BTF in eliminating the influent 2-EH. Treatment of Gaseous VOC Emissions from A Resin-Manufacturing Plant by A Full-Scale Biotrickling Filter A resin and chemical company located in Tainan County, Taiwan engages in the manufacture of PU (poly urethane), PVAC (poly vinyl acetate), PS (poly styrene), and PMMA (poly methyl methacrylate) resins from various chemical stocks. Gaseous volatile organic compounds (VOCs) emitted from the reactors include toluene, methyl ethyl ketone (MEK), acetone, vinyl chloride, styrene, butyl acetate, 2-ethyl hydroxyl acetate, and methyl methacrylate. These VOCs should be properly eliminated before discharging the reactor vents to the atmosphere. This paper reports the performance results of using a biotrickling filter (BTF) with wood packings (sizes = 2-12 cm and specific surface area = 97 m2/m3) for treating the reactor vents with a total flowrate of 80 m3/min at 20-30¢J. The BTF was constructed from a 7.0 m x 6.0 m (ID x H) SUS 304 column with wood packings of 4.0 m in height. The operation started with the conditions of recirculation liquid pH = 7.0-8.0 and rate (VL) = 1.56 m3/m2.h, a steady nutrient (urea and phosphate phosphorus) addition, and without a special microbial seeding. Results indicate that, yellowish-brown biofilms on the surface of packings could be observed in one week and well developed in two weeks after the start-up operation. Long-term operation results show that, in the conditions of influent VOC concentration C0 = 200-10000 ppm (expressed in terms of methane), U0 = 125 m3/m2.h, and gas empty-bed-retention time EBRT = 115 s, K/L could be correlated by the equation K/L = 345/(467+L) with a correlation coefficient (R) of 0.9913. The VOC elimination rate was mass-transfer limited when L<45 g/m3.h, with the mass of VOCs expressed as that of methane. Results also indicate that the liquid recirculation might be interrupted for a hour without influencing the performance. Toluene was the most difficult one to eliminate among the VOCs in the gas stream.

Biofuels are of particular interest as they have the potential to reduce our dependence on petroleum-derived fuels for transportation. 1-Hexanol is a promising renewable long chain alcohol that can be used in conventional fuel blends or as a cosolvent for biodiesel mixtures. However, the fundamental combustion properties of 1-hexanol have not been fully characterized in the literature. Thus, new experimental results, consisting of temperature and concentration profiles of stable species were obtained for the oxidation of 1-hexanol generated in an opposed-flow diffusion flame at 0.101 MPa. The kinetic model consists of 361 chemical species and 2687 chemical reactions (most of them reversible). This experimental data were compared to the predicted values of a detailed chemical kinetic model proposed in literature to study the combustion of 1-hexanol. Reaction pathway and sensitivity analyses were performed to interpret the results. In addition, several improvements were investigated to optimize the proposed chemical kinetic mechanism.

Biofuels are of particular interest as they have the potential to reduce our dependence on petroleum-derived fuels for transportation. 1-Hexanol is a promising renewable long chain alcohol that can be used in conventional fuel blends or as a cosolvent for biodiesel mixtures. However, the fundamental combustion properties of 1-hexanol have not been fully characterized in the literature. Thus, new experimental results, consisting of temperature and concentration profiles of stable species were obtained for the oxidation of 1-hexanol generated in an opposed-flow diffusion flame at 0.101 MPa. The kinetic model consists of 361 chemical species and 2687 chemical reactions (most of them reversible). This experimental data were compared to the predicted values of a detailed chemical kinetic model proposed in literature to study the combustion of 1-hexanol. Reaction pathway and sensitivity analyses were performed to interpret the results. In addition, several improvements were investigated to optimize the proposed chemical kinetic mechanism.

The biophysical properties and distribution of voltage gated ion channels shape the spatio-temporal pattern of synaptic inputs and determine the input-output properties of the neuron. Of the various voltage-gated ion channels, persistent Na⁺ current (INaP) is of interest because of its activation near rest, slow inactivation kinetics, and consequent effects on excitability. Overshadowed by transient Na⁺ current (INaT) of large amplitude and fast inactivation, various quantitative characterizations of INaP have yet to provide a clear understanding of their role in neuronal excitability. We addressed this question using quantitative electrophysiology to compare somatic INaP and INaT in 4–7 week old Sprague-Dawley rat hippocampal CA1 pyramidal neurons. INaP was evoked with 0.4 mV/ms ramp voltage commands and INaT with step commands in hippocampal neurons from in vitro brain slices utilizing nucleated patch-clamp recording. INaP was found to have a density of 1.4 ± 0.7 pA/pF in the soma. Compared to INaT, it has a much smaller amplitude (2.38% of INaT) and distinct voltage dependence of activation (16.7 mV lower half maximal activation voltage and 41.3% smaller slope factor than those of INaT). The quantitative measurement of INaT gave the activation time constant ([tau]m) of 22.2 ± 2.3 [mu]s at 40 mV. Hexanol, which has anesthetic effects, was shown to preferentially block INaP compared to INaT with a significant voltage threshold elevation (4.6 ± 0.7 mV) and delayed 1st spike latency (221 ± 54.6 ms) suggesting reduced neuronal excitability. The number of spikes evoked by either given step current injections or [alpha]-EPSP integration was also significantly decreased. The differential blocking of INaP by halothane, a popularly used volatile anesthetic, further supports the critical role of INaP in setting voltage threshold. Taken together, the presence of INaP in the soma demonstrates an intrinsic mechanism utilized by hippocampal CA1 pyramidal neurons to regulate axonal spike initiation through different biophysical properties of the Na⁺ channel. Furthermore, INaP becomes an interesting target of intrinsic plasticity because of its profound effect on the input-output function of the neuron. / text

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In recent years, there have been a number of studies looking at inhibition of microorganisms by spices, herbs or their extracts.  Many of these products have been shown to have antimicrobial activity against foodborne pathogens.  The purpose of this research was to evaluate the antimicrobial activity of three essential oil (EO) compounds (thymol, eugenol, and trans-cinnamaldehyde) alone and in combination with three naturally-occurring apple aroma (AA) compounds (hexanal, trans-2-hexenal and 1-hexanol) to identify the minimum inhibitory concentrations necessary to inhibit E. coli O157:H7.  Three commercial apple juice flavoring mixtures (natural apple cinnamon, natural apple spice and natural red apple) were additionally tested alone for antimicrobial activity against E. coli O157:H7. The standard agar dilution method (SAD) and checkerboard assay were used to evaluate the efficacy of the nine compounds, alone and in combination against E. coli O157:H7.  In general, the EO compounds were significantly more effective against E. coli O157:H7 than the AA compounds (P<0.05).  Cinnamaldehye, with an MIC of 0.2 mg/mL, exhibited the highest degree of activity, followed by thymol, eugenol and trans-2-hexenal, which each had individual MIC values of 1.6 mg/mL.  No synergism was found in the combinations of EO compounds with AA compounds. / Master of Science in Life Sciences

Indiana University-Purdue University Indianapolis (IUPUI) / Solid phase micro-extraction is a powerful and versatile technique, well-suited to the analysis of numerous samples of forensic interest. The exceptional sensitivity of the SPME platform, combined with its adaptability to traditional GC-MS systems and its ability to extract samples with minimal work-up, make it appropriate to applications in forensic laboratories. In a series of research projects, solid phase micro-extraction was employed for the analysis of explosives, commercial tire treatments, and entomological specimens. In the first project, the volatile organic compounds emanating from two brands of pseudo-explosive training aids for use in detector dog imprinting were determined by SPME-GC-MS, and the efficacy of these training materials was tested in live canine trials. In the second project, the headspace above various plasticizers was analyzed comparative to that of Composition C-4 in order to draw conclusions about the odor compound, 2- ethyl-1-hexnaol, with an eye toward the design of future training aids. In the third, automobile tires which had participated in professional race events were analyzed for the presence of illicit tire treatments, and in the fourth, a novel SPME-GC-MS method was developed for the analysis of blowfly (Diptera) liquid extracts. In the fifth and final project, the new method was put to the task of performing a chemotaxonomic analysis on pupa specimens, seeking to chemically characterize them according to their age, generation, and species.

Petrochemical and fine chemical industries face a daunting problem in recovering acetic acid from its aqueous solutions. The recovery of acetic acid could be done through esterification reaction. However, esterification is an equilibrium limited reaction. Multi-functional reactors such as chromatographic reactor (CR) and reactive distillation column (RDC) are promising technologies mainly for equilibrium limited reactions wherein reaction and separation of products are carried out in a single equipment that tends to shift the equilibrium towards the desired direction which is not possible in a classical batch reactor. Physical and chemical characterisation of ion exchange resin catalysts such as scanning electron microscopy, Brunauer-Emmett-Teller (BET) surface area measurement, pore size distribution, elemental analysis, true density and particle size distribution were carried out to access the catalysts performance for n-hexyl acetate synthesis. Esterification of acetic acid with n-hexanol was studied with both dilute and concentrated acid in the presence of cation exchange resins (macroporous and gelular) in a jacketed stirred batch reactor to synthesise a value added ester, namely n-hexyl acetate and also to study the recovery of acetic acid from the waste aqueous streams. The effect of various parameters such as speed of agitation, catalyst particle size, feed mole ratio of n-hexanol to acetic acid, reaction temperature, catalyst loading and reusability of catalysts was studied for the optimisation of the reaction condition in a batch reactor. The non-ideality of each component in the reacting mixture was accounted for by using the activity coefficient via the use of the UNIFAC group contribution method. The kinetic data were correlated with both pseudo-homogeneous (PH) and adsorption based heterogeneous reaction rate models, e.g., Eley-Rideal (ER), Langmuir-Hinshelwood-Hougen-Watson (LHHW), and the modified LHHW (ML). Pseudo-homogeneous (PH) model gave the best representation of the kinetic data found experimentally. The feasibility of reactive distillation for the recovery of acetic acid using n-hexanol was evaluated through residue curve map (RCM) determination experiments. RCM provides information to a design engineer of the existence of separation boundaries imposed by the singular points corresponding to the reactive/non-reactive azeotropes, thus provides an insight into the feasibility of reactive distillation for this purpose. A laboratory scale batch chromatographic reactor was designed and constructed. Batch chromatographic reactor experiments were carried out using different parameters such as feed flow rate, feed mole ratio of n-hexanol to acetic acid, desorbent (n-hexanol) flow rate and reaction step to maximise the formation of n-hexyl acetate as well to achieve complete conversion of acetic acid. Continuous chromatographic reactor was designed, constructed and commissioned on the basis of the results obtained from the batch chromatographic reactor experiments. The experiments carried out in continuous chromatographic reactor correlated very well with the results from the batch chromatographic reactor for the optimised condition.