The rapid accumulation of municipal solid waste is a significant environmental concern in our rapidly growing world. Due to its low cost, high energy recovery and limited environmental impact anaerobic digestion (AD) is a promising solution for stabilizing the organic fraction of municipal solid waste (OFMSW). Hydrolysis is often the rate-limiting step during AD of wastes with high solid content; this step can be accelerated by pretreatment of waste prior to AD. This thesis presents the results of alkaline pretreatment of OFMSW using NaOH and KOH. Four different pH levels 10, 11, 12 and 13 at two temperatures 23±1°C and 80±1°C were examined to study the effects of the pretreatment on (i) enhancing the solubility of the organic fraction of the waste, and (ii) enhancing the AD process and the biogas production. The effects on solubility were investigated by measuring changes in the soluble COD (SCOD) concentrations of pretreated wastes and the enhanced AD was investigated by measuring volatile solids (VS) destruction, total COD (TCOD) and SCOD removal in addition to biogas and methane production using biochemical methane potential (BMP) assay and semi-continuous laboratory reactor experiments. Pretreatment at pH 13 at 80±1°C demonstrated the maximum solubility for both NaOH and KOH pretreated samples; however the BMP analysis demonstrated that pretreatment at pH 12 at 23±1°C showed the greatest biogas yield relative to the removed VS for both chemicals. Thus pretreatment at pH 12 at 23±1°C using NaOH and KOH were examined using semi-continuous reactors at three different HRTs: 10, 15 and 20 days. Pretreatment demonstrated a significant improvement in the AD performance at SRTs of 10 and 15 days.

It is government policy that the UK’s intermediate level radioactive wastes (ILW) will be disposed of in a deep geological disposal facility (GDF), where cementitious materials will be ubiquitous. After ILW disposal, groundwater ingress through the engineered facility is expected, forming a hyperalkaline plume from the cementitious materials into the surrounding host rock. This will form a persistent, high pH, “chemically disturbed zone” over timescales of 105 - 106 years, that will evolve from pH >13 to pH 10 over time. In the deep subsurface, microbial processes, particularly metal reduction may immobilise redox active radioactive contaminants in the waste, yet these reactions remain poorly characterised under these extreme conditions. In this project, microbiologically-mediated Fe(III) reduction was explored under alkaline conditions in sediment from a lime workings site in Buxton, UK, as an analogue for an ILW impacted subsurface environment. In addition, the impact of these processes on radionuclide (U, Tc and Np) behaviour was considered. Microcosms were set up using sediments taken from the site, adjusted to pH 10, augmented with electron donor (organic acids with yeast extract) and Fe(III), U(VI), Tc(VII) or Np(V) as electron acceptors. Biogeochemical processes were monitored using geochemistry, microbial ecology and X-ray absorption spectroscopy (XAS) techniques. A cascade of microbial reduction processes occurred at pH 10 – 10.5 in all microbially active systems. In Fe(III) enriched systems, the dominant post-reduction mineral phase was magnetite and the rate and extent of Fe(III) reduction was increased in the presence of extracellular (AQDS, Aldrich humic acid) and endogenous (riboflavin) electron shuttles. In U(VI) supplemented sediment systems, partial U(VI) reduction occurred to a non-uraninite phase, which was susceptible to reoxidation by air (O2) and nitrate. By contrast, in Fe(III)-augmented microcosms, more complete U removal to solids was noted, with uraninite identified as the end product, which was also reoxidised by air (O2) and nitrate. In these experiments there was, however, evidence to suggest that uranium was associated with the reoxidised Fe(III) mineral. In Tc supplemented microcosm experiments, complete Tc(VII) reduction occurred in systems with and without added Fe(III). In the microcosms with no added Fe(III) however, only partial Tc removal from solution occurred, despite evidence for complete reduction, suggesting that soluble or colloidal Tc(IV) may be present. Moderate Tc reoxidation occurred with air (O2) in both systems with and without added Fe(III) however no Tc remobilisation occurred during reoxidation with added nitrate. XAS on Fe(III) enriched sediments that had been microbially reduced and then re-oxidised by air, indicated that Tc may be associated with the reoxidised Fe mineral phase in these experiments. In the Np experiments, significant Np(V) sorption to sediments with and without added Fe(III) occurred initially, followed by Np(V) bioreduction to Np(IV). In all experiments, microbial (16S rRNA gene) profiling suggested a role for novel Gram-positive bacteria in Fe(III) and radionuclide reduction. These results highlight the significance of microorganisms on radionuclide biogeochemistry at high pH and have implications for the safe disposal of intermediate level nuclear wastes.

The objectives of this project were to determine the reaction schemes of formanilide and substituted formanilides in acidic and alkaline solutions, to quantiate the kinetics of hydrolysis, to propose reaction mechanisms, and to assess the role of ortho words substitution in formanilide hydrolysis kinetics. A set of thirty substituted formanilides were synthesized and characterized. Hydrolysis of the formanilides was carried out under first order conditions in hydrochloric acid (0.01-8 M, 40°C) and in hydroxide solutions (0.01-3 M, 25°C and 40°C). Hydrolysis kinetics were evaluated in terms of temperature (20°C- 60°C), solvent composition (0-50 % dimethyl sulfoxide, dioxane, ethanol and acetone) and ionic strength (0.1-1) effects. The degradation products were separated and identified using RP-HPLC, and the alkaline and acidic reaction schemes were proposed. For acidic hydrolysis of formanilides, the observed rate constants were proportional to the hydronium concentrations. Modified Hammett plots constructed using the second order rate constants for specific acid catalysis were linear. The ortho effect was analyzed using the Fujita-Nishioka method. In alkaline solutions the observed rate constants showed mixed first and second order dependences with respect to hydroxide concentration. A complex degradation scheme was used to estimate individual rate constants and to construct Hammett plots. Ortho effects were examined for the first order hydroxide concentration dependent pathway. Arrhenius plots for substituted formanilides were linear in both acidic and alkaline media. Ionic strength did not show any effect on the acidic and alkaline hydrolysis rates. In both acidic and alkaline media the rate of hydrolysis decreased with increase in organic solvent content. Formanilide hydrolyzes in acidic solutions by specific acid catalysis and the kinetic study results were consistent with AAC2 mechanism. Ortho substitution led to reduction in rates. The orthoeffect could be split in steric inhibition of resonance, retardation due to steric bulk and through space interactions. In alkaline solutions a complicated kinetic scheme was used to describe the multiple pathways of degradation. The results from the kinetic studies could be explained using a modified BAC2 mechanism. The hydrolysis of meta and parasubstituted formanilides in alkaline conditions did not show substituent effects however ortho substitution led to an decrease in rate constants proportional to the steric bulk of the substituent.

Gas chromatographic acquisition of representative 'Total' cellular fatty acid profiles from bacteria or bacteria-containing samples (e.g., environmental or clinical materials) tends to be dependent on the method used to released the fatty acids and convert them to derivatives suitable for analysis. Alkaline saponification or interesterification methods, while preserving acid-sensitive components such as cyclopropane fatty acids, are often insufficient to release amide-linked components, such as hydroxylated fatty acids. Acid-catalyzed hydrolyses or interesterifications, on the other hand, while more efficiently releasing the predominantly amide-linked hydroxylated components, have been shown to cause severe and unpredictable degradation of cyclopropane fatty acids. We report studies of a single-tube method involving sequential alkaline/acid release of fatty acids in which fatty acids released by the alkaline step are partitioned into an organic epiphase during the aqueous acid hydrolysis step. After hydrolysis, the epiphase and the released fatty acids are extracted into an hypophasic solvend and esterified at moderate temperature under relatively low acid concentrations. Under these conditions, cyclopropane as well as hydroxylated fatty acids are recovered in high yield.

Background: Tissue non-specific alkaline phosphatase (TNAP) is an enzyme which functions within the body to catalyze the hydrolysis of pyrophosphate to phosphate, and is a well-known mediator of bone mineralization. It has also been identified as a positive mediator of intracellular lipid accumulation (ICLA) in both murine and human preadipocytes as well as in the hepatocellular cell line HepG2. However, the mechanism through which TNAP functions to control ICLA is not known. Both osteoblasts and adipocytes are both of mesenchymal origin and thus may share conserved mechanisms through which TNAP functions. Within bone, TNAP converts pyrophosphate (which inhibits mineralization) to phosphate. This phosphate is essential to the mineralization process through binding to hydroxyapatite crystals, and it also activates the transcription of genes whose products function in osteoblast differentiation, including NRF2. This thesis therefore aimed to determine the role of both pyrophosphate and TNAP-generated phosphate in ICLA. In addition, it is possible that TNAP may interact with other proteins, as it is known that TNAP is able to dephosphorylate proteins such as tau. This thesis therefore aimed to determine whether TNAP binds to other proteins in the context of ICLA. Lipids are not only stored within hepatocytes and adipocytes, but are also found in cells of the adrenal cortex, and TNAP is known to be expressed within such cells. Therefore, this thesis also aimed to determine whether TNAP is involved in the accumulation of cholesterol esters within lipid droplets in the adrenal cortex. Methods: To determine the effect of high intracellular pyrophosphate levels on ICLA, 3T3-L1 cells (a preadipocyte cell line) were cultured in the presence and absence of probenecid, an inhibitor of the pyrophosphate transporter ANK, and induced to accumulate lipids. Lipid accumulation was monitored through Oil red O staining. The effect of probenecid treatment on TNAP activity and intracellular pyrophosphate levels was also analysed. To determine whether TNAP functions in ICLA by producing phosphate for gene induction, 3T3-L1 cells were stimulated to undergo ICLA in the presence and absence of the TNAP inhibitor levamisole, which in turn blocks ICLA. Levamisole treated cells were also incubated with phosphate to see if this would overcome the inhibitory effect of levamisole on ICLA. The ability of phosphate to induce gene expression of NRF2 was determined through real-time PCR. In addition, an NRF2 expressing plasmid was transfected into cells treated with the TNAP inhibitor levamisole to determine if this would also overcome the block on ICLA caused by TNAP inhibition. In silico analysis identified TRAF2 as a potential binder of TNAP. The expression of TRAF2 during ICLA was determined through real time PCR, and the effect of overexpression of TRAF2 on intracellular lipid accumulation was determined through the transfection of a TRAF2 expressing plasmid in cells induced to undergo ICLA. To determine whether TNAP modulates lipid accumulation in cells of the adrenal cortex, the Y1 murine adrenocortical cell line was cultured in the presence and absence of TNAP inhibitor levamisole, and ICLA measured by Oil Red O staining. The location of TNAP within Y1 cells was identified by histochemical staining. Results: Cells treated with probenecid showed increased pyrophosphate levels (expressed as a % of levels observed at baseline) when compared to untreated controls (155.5 ± 15.1 % vs 51.1 ± 18.9 %; p=0.001) after 24 hours of culture. Increased pyrophosphate levels resulted in ICLA within 3T3-L1 cells surpassing levels seen in untreated controls (507.4 ± 30.4 % vs 337.6 ± 16.17 %; p=0.004). This increase in pyrophosphate was coupled to an increase in TNAP activity within the initial 24 hours (291.5 ± 72.8 % vs baseline of 100%; p=0.038) compared to that seen in control experiments (103.43 ± 24.3 % vs baseline of 100%; p=0.848). Cells treated with levamisole showed minimal ICLA and when exogenous phosphate was added, lipid levels were reconstituted to levels similar to that seen in cells induced to accumulate lipids in the absence of levamisole (284.01 ± 62.52% vs 275.86 ± 35.52%; p= 0.83). In the presence of levamisole plus exogenous phosphate, NRF2 expression was upregulated within 1 hour of treatment to levels greater than that seen in the absence of phosphate but presence of levamisole (216.64 ± 19.24% vs 98.28 ± 3.79%; p=0.004). Expression of NRF2 (through transfection with an NRF2 expression plasmid) in cells deficient in TNAP activity (via levamisole treatment), and induced to accumulate lipids, was not able to completely reconstitute ICLA when compared to cells not treated with levamisole (193.72 ± 16.51 vs 326.46 ± 47.64; p = 0.019), but ICLA was still greater than that observed at baseline. In silico analysis predicted that TNAP would bind to TRAF2, yet neither band shift assays nor immune co-precipitation showed evidence of this. However, TRAF2 mRNA was down regulated within 3T3-L1 cells during adipogenesis, reaching levels of 15.27 ± 10.27% (p= 0.014) of baseline (levels prior to induction of intracellular lipid accumulation) by day 4 of lipid accumulation. Overexpression of TRAF2 during adipogenesis markedly reduced intracellular lipid accumulation (147.88 ± 11.28% vs 326.46 ± 47.64%; p=0.028 (after 8 days of culture)). In Y1 cells TNAP activity is upregulated during ICLA, reaching 233 ± 37.56% (p=0.019 vs. baseline) of baseline levels within the initial 24 hours. Inhibition of TNAP activity through levamisole treatment resulted in a decrease in ICLA when compared to cells not treated with levamisole. Histochemical analysis showed that TNAP activity was localised to the lipid droplet. Discussion and Conclusions: Within 3T3-L1 cells TNAP mediates intracellular lipid accumulation through the generation of phosphate. The phosphate is able to increase the expression of NRF2, however it is likely that NRF2 is not the only gene whose expression is regulated by TNAP-generated phosphate. It was found that TNAP and TRAF2 do not bind to each other in the context of ICLA; however TRAF2 is a negative mediator of ICLA through a TNAP-independent mechanism. Functional TNAP is necessary for the accumulation of cholesterol esters within the Y1 cell line, suggesting that TNAP is essential for lipid accumulation in cell types that store lipids in intracellular membrane-bound droplets in the form of triglycerides or cholesterol esters. / GR2018

This thesis describes research to understand the relationships between materials, microstructure, transport processes, and battery performance for primary alkaline battery cathodes. Specifically, the effect of various carbon additives, with different physical properties, on electronic transport or conductivity within battery cathodes was investigated. Generally, the electronic conductivity increases with carbon additives that have higher aspect ratios, smaller particle diameters, higher surface areas, and lower bulk densities. Other favorable carbon aspects include more aggregated and elongated carbon domains which permit good particleto-particle contacts. Of the various carbon additives investigated, graphene nanopowder was the best performer. This graphene nanopowder had the smallest particle diameter, highest surface area, and one of the lowest Scott densities of the carbon additives investigated as well as well-connected, interspersed carbon pathways. Notably, a typical effective ionic conductivity is more than 50 times less than the electronic conductivity (5.7 S/m to 300 S/m, respectively) for a high-performance cathode. Thus, alkaline battery cathodes could be redesigned to improve ionic conductivity for optimal performance. This work expanded on previously published work by relating additional carbon-additive material properties--specifically, particle morphology, surface area and Scott density--and their corresponding cathode microstructure to the fundamental transport processes in alkaline battery cathodes.

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<p>Subject Category "Geology" not listed in menu.</p> / <p>An Alkalic suite of proterozoic volcanics and their associated sediments, situated within the Dubawnt Group of the Churchill Province, was mapped and studied. Petrography and geochemical analyses were performed on representative specimens. The extrusives and related dykes are thought to have been derived from the differentiation of a single parent magma, as evidenced by several geochemical trends. The units are as follows; intermediate to felsic trachytes and pyroclastics, typically phlogopite phyric and red alkali rhyolites; later volcaniclastic units. A significantly younger diabase dyke cuts these units, all of which overlie the '307' formation.</p> / Bachelor of Science (BSc)

This thesis is missing page 89, no other copy of the thesis has this page. -Digitization Centre / The vanadium mediated electrolysis of hydrogen sulphide has been demonstrated in a bench top pilot plant. The first step in the process is the absorption of hydrogen sulphide from a sour gas stream into an carbonate buffered liquor, pH 9. In the presence of citrate ion, the vanadium (V) in the liquor is reduced to vanadium (IV) by (hydro) sulphide ion, which is oxidized to yellow elemental sulphur. The vanadium (IV) rich solution is then pumped to an electrolysis cell where the vanadium (IV) is reoxidized to vanadium (V) and protons are reduced to elemental hydrogen. The reoxidized liquor is then returned to the absorber. The oxidation of vanadium (IV) to vanadium (V) in the liquor was found to be electrochemically irreversible. The current efficiency for vanadium (IV) oxidation exceeded 90 percent. The voltametric half-wave potential at platinum, was 0.34 v (vs Ag/AgCl, sat. KC1). With the slippage of sulphide or polysulphide ion into the electrolysis cells, the electrodes became passivated with electrodeposited sulphur. This resulted in an increased anode potential demand which may promote the electrosynthesis of oxygen and sulphate ion. The oxidation of vanadium (IV) at the anode releases 4 protons and acidifies the solution adjacent the electrode surface. This may induce carbon dioxide evolution and inhibit the discharge of vanadium (IV). The inhibition appears as a suppressed current and an anodic shift in the voltametric half-wave potential. This inhibition can be minimized at high pH levels in the liquor, buffer capacity., and citrate concentration. The irreversibility of the vanadium (IV/V) couple allows electrolysis cells to be constructed without a cell membrane. This is a significant advantage which will offset the cost of large electrolysis cells. Large cells will enable high energy efficiencies to hydrogen production to be realized. Energy efficiencies greater than 0.28 m3 /kwhr may be indicated. This study features a critical review of sulphide electro-oxidation, a factorial designed voltametric experiment, and a newly identified catalytic response in the polarographic analysis of sulphide ion. / Thesis / Master of Science (MS)