<p>The primary aim of these coal fired industries for co-disposing fly ash and brine was to use the fly ash as a sustainable salt sink. It is therefore important to study the interaction chemistry of the fly ash-brine systems to fully understand the leaching and mobility of the contaminant species, and to determine the possibility of capturing the salts from the brine solution when fly ash and brine are co-disposed. In order to achieve the aims and objectives of this study, several leaching procedures such as batch reaction tests, long-term fly ash-brine interaction tests, acid neutralization capacity (ANC) tests, up-flow percolation tests and sequential extraction tests were employed. The geochemical modeling software was applied to predict the formation of secondary mineral phases controlling the release of species in the fly ash-brine systems. Several analytical techniques such as x-ray diffraction (XRD), x-ray fluorescence (XRF), scanning electron microscopy-energy dispersion spectroscopy (SEM-EDS), inductively coupled plasma-mass spectroscopy (ICP-MS) and ion chromatography (IC) were applied to characterize the fresh fly ashes, solid residues recovered from the fly ash-brine interaction tests, the brine sample used in this study and the leachate samples in order to determine the chemical and mineralogical compositions and speciation of the waste materials.</p>

In the production of biodiesel via the transesterification of vegetable oils, purification to international standards is challenging. A key measure of biodiesel quality is the level of free glycerol in the biodiesel. In order to remove glycerol from fatty acid methyl ester (FAME or biodiesel), a membrane separation setup was tested. The main objective of this thesis was to develop a membrane process for the separation of free glycerol dispersed in FAME after completion of the transesterification reaction and to investigate the effect of different factors on glycerol removal. These factors included membrane pore size, pressure, temperature, and methanol, soap and water content. First, a study of the effect of different materials present in the transesterification reaction, such as water, soap, and methanol, on the final free glycerol separation was performed using a modified polyacrylonitrile (PAN) membrane, with 100 kD (ultrafiltration) molecular weight cut off for all runs at 25°C. Results showed low concentrations of water had a considerable effect in removing glycerol from the FAME. The mechanism of separation of free glycerol from FAME was due to the removal of an ultrafine dispersed glycerol-rich phase present in the untreated (or raw) FAME. The size of the droplets and the free glycerol separation both increased with increasing water content of the FAME. Next, three types of polymeric membranes in the ultrafiltration range with different molecular weight cut off, were tested at three fixed operating pressures and three operating temperatures (0, 5 and 25oC) to remove the free glycerol from a biodiesel reactor effluent. The ASTM standard for free glycerol concentration was met for the experiments performed at 25°C. The results of this study indicate that glycerol could be separated from raw FAME to meet ASTM and EN standards at methanol feed concentrations of up to 3 mass%. The process was demonstrated to rely on the formation of a dynamic polar layer on the membrane surface. Ceramic membranes of different pore sizes (0.05 µm (ultrafiltration (UF) range) and 0.2 µm (microfiltration (MF) range)) were used to treat raw FAME directly using the membrane separation set up at temperatures of 0, 5 and 25°C. The results were encouraging for the 0.05 µm pore size membrane at the highest temperature (25°C). The effect of temperature on glycerol removal was evident from its relation with the concentration factor (CF). Higher temperatures promoted the achievement of the appropriate CF value sooner for faster separation. Membrane pore size was also found to affect separation performance. A subsequent study revealed the effect of different variables on the size of the glycerol droplets using dynamic light scattering (DLS). A key parameter in the use of membrane separation technology is the size of the glycerol droplets and the influence of other components such as water, methanol and soaps on that droplet size. The effect of water, methanol, soap and glycerol on the size of suspended glycerol droplets in FAME was studied using a 3-level Box-Behnken experimental design technique. Standard statistical analysis techniques revealed the significant effect of water and glycerol on increasing droplet size while methanol and soap served to reduce the droplet size. Finally, a study on the effect of trans-membrane pressure (TMP) at different water concentrations in the FAME phase on glycerol removal using UF (0.03 µm pore size, polyethersulfone (PES)) and MF (0.1 and 0.22 µm pore sizes, PES) membranes at 25, 40 and 60°C was performed. Results showed that running at 25°C for the two membrane types produced the best results for glycerol removal and exceeded the ASTM and EN standards. An enhancement of glycerol removal was found by adding small amounts of water up to the maximum solubility limit in biodiesel. An increase in temperature resulted in an increase in the solubility of water in the FAME and less effective glycerol removal. Application of cake filtration theory and a gel layer model showed that the gel layer on the membrane surface is not compressible and the specific cake resistance and gel layer concentration decrease with increasing temperature. An approximate value for the limiting (steady-state) flux was reported and it was found that the highest fluxes were obtained at the lowest initial water concentrations at fixed temperatures. In conclusion, dispersed glycerol can be successfully removed from raw FAME (untreated FAME) using a membrane separation system to meet the ASTM biodiesel fuel standards. The addition of water close to the solubility limit to the FAME mixture enables the formation of larger glycerol droplets and makes the separation of these droplets straightforward.

The teneurin C-terminal associated peptides (TCAP) are a family of four predicted peptides that are expressed in all metazoans where the teneurins have been studied to date. Of the four peptides, TCAP-1 has been studied most extensively. In vitro, TCAP-1 increases neuronal proliferation and neurite outgrowth. In vivo, the peptide reduces CRF-induced behavioural responses in rats. Despite the large body of evidence indicating a strong biological role for TCAP-1, little is known about the chemistry and solubility of the peptide, or the signaling pathway(s) mediating these effects. The aim of this research was to appropriately solubilize the peptide and to develop detection assays for its study in greater detail. I have now established an appropriate formulation of TCAP-1 and developed an immunoassay to assess its concentrations in tissues and in circulation. Also, by examining a number of transcriptional response elements, I have found two assays for probing the signal transduction mechanisms of this peptide.

The teneurin C-terminal associated peptides (TCAP) are a family of four predicted peptides that are expressed in all metazoans where the teneurins have been studied to date. Of the four peptides, TCAP-1 has been studied most extensively. In vitro, TCAP-1 increases neuronal proliferation and neurite outgrowth. In vivo, the peptide reduces CRF-induced behavioural responses in rats. Despite the large body of evidence indicating a strong biological role for TCAP-1, little is known about the chemistry and solubility of the peptide, or the signaling pathway(s) mediating these effects. The aim of this research was to appropriately solubilize the peptide and to develop detection assays for its study in greater detail. I have now established an appropriate formulation of TCAP-1 and developed an immunoassay to assess its concentrations in tissues and in circulation. Also, by examining a number of transcriptional response elements, I have found two assays for probing the signal transduction mechanisms of this peptide.

In the production of biodiesel via the transesterification of vegetable oils, purification to international standards is challenging. A key measure of biodiesel quality is the level of free glycerol in the biodiesel. In order to remove glycerol from fatty acid methyl ester (FAME or biodiesel), a membrane separation setup was tested. The main objective of this thesis was to develop a membrane process for the separation of free glycerol dispersed in FAME after completion of the transesterification reaction and to investigate the effect of different factors on glycerol removal. These factors included membrane pore size, pressure, temperature, and methanol, soap and water content. First, a study of the effect of different materials present in the transesterification reaction, such as water, soap, and methanol, on the final free glycerol separation was performed using a modified polyacrylonitrile (PAN) membrane, with 100 kD (ultrafiltration) molecular weight cut off for all runs at 25°C. Results showed low concentrations of water had a considerable effect in removing glycerol from the FAME. The mechanism of separation of free glycerol from FAME was due to the removal of an ultrafine dispersed glycerol-rich phase present in the untreated (or raw) FAME. The size of the droplets and the free glycerol separation both increased with increasing water content of the FAME. Next, three types of polymeric membranes in the ultrafiltration range with different molecular weight cut off, were tested at three fixed operating pressures and three operating temperatures (0, 5 and 25oC) to remove the free glycerol from a biodiesel reactor effluent. The ASTM standard for free glycerol concentration was met for the experiments performed at 25°C. The results of this study indicate that glycerol could be separated from raw FAME to meet ASTM and EN standards at methanol feed concentrations of up to 3 mass%. The process was demonstrated to rely on the formation of a dynamic polar layer on the membrane surface. Ceramic membranes of different pore sizes (0.05 µm (ultrafiltration (UF) range) and 0.2 µm (microfiltration (MF) range)) were used to treat raw FAME directly using the membrane separation set up at temperatures of 0, 5 and 25°C. The results were encouraging for the 0.05 µm pore size membrane at the highest temperature (25°C). The effect of temperature on glycerol removal was evident from its relation with the concentration factor (CF). Higher temperatures promoted the achievement of the appropriate CF value sooner for faster separation. Membrane pore size was also found to affect separation performance. A subsequent study revealed the effect of different variables on the size of the glycerol droplets using dynamic light scattering (DLS). A key parameter in the use of membrane separation technology is the size of the glycerol droplets and the influence of other components such as water, methanol and soaps on that droplet size. The effect of water, methanol, soap and glycerol on the size of suspended glycerol droplets in FAME was studied using a 3-level Box-Behnken experimental design technique. Standard statistical analysis techniques revealed the significant effect of water and glycerol on increasing droplet size while methanol and soap served to reduce the droplet size. Finally, a study on the effect of trans-membrane pressure (TMP) at different water concentrations in the FAME phase on glycerol removal using UF (0.03 µm pore size, polyethersulfone (PES)) and MF (0.1 and 0.22 µm pore sizes, PES) membranes at 25, 40 and 60°C was performed. Results showed that running at 25°C for the two membrane types produced the best results for glycerol removal and exceeded the ASTM and EN standards. An enhancement of glycerol removal was found by adding small amounts of water up to the maximum solubility limit in biodiesel. An increase in temperature resulted in an increase in the solubility of water in the FAME and less effective glycerol removal. Application of cake filtration theory and a gel layer model showed that the gel layer on the membrane surface is not compressible and the specific cake resistance and gel layer concentration decrease with increasing temperature. An approximate value for the limiting (steady-state) flux was reported and it was found that the highest fluxes were obtained at the lowest initial water concentrations at fixed temperatures. In conclusion, dispersed glycerol can be successfully removed from raw FAME (untreated FAME) using a membrane separation system to meet the ASTM biodiesel fuel standards. The addition of water close to the solubility limit to the FAME mixture enables the formation of larger glycerol droplets and makes the separation of these droplets straightforward.

No description available.

The main purpose of this study is to compare the effectiveness of case- based learning method instruction over traditional method instruction on eleventh grade high school students&rsquo / understanding of solubility equilibrium concepts. In addition, students&rsquo / attitudes toward chemistry as a school subject and students&rsquo / epistemological beliefs were investigated. Sixty-two eleventh grade students from two classes of a chemistry course taught by the same teacher in Atakent High School in 2007-2008 spring semesters were enrolled in the study. The classes were randomly assigned as experimental and control group. Experimental group students instructed by case-based learning method in which specific situations, generally real-life examples were discussed. On the other hand, control group students were instructed by traditional method. Solubility Concept Test was administered as a pre-test to both groups. Moreover, Attitude Scale toward chemistry and Epistemological Belief Scale about chemistry were administered as a pre- and post-tests to all groups. Solubility Equilibrium Concept Test and Open-Ended Solubility Equilibrium Concept Test were administered as a post-test to all groups. The results showed that case based learning instruction produced significantly greater achievement in understanding of solubility equilibrium than the traditional instruction. Also, there was a significant difference between the experimental and the control group with respect to their epistemological beliefs and attitudes toward chemistry as a school subject in the favor of experimental group. Results obtained revealed that students have several misconceptions related to solubility equilibrium. Case based learning was effective for remediation of misconceptions and enhancing students&rsquo / understanding in comparison to traditional method.

The purpose of this study was to investigate the effect of instruction based on 5E learning cycle model (LCI) compared to Traditional Instruction (TI) and gender on 11th grade students&rsquo / understanding of solubility equilibrium concept, students&rsquo / perceived motivation, use of learning strategies, and attitudes towards chemistry. There were 53 students in the experimental group instructed by the LCI and 56 students in the control group instructed by the TI. Solution Concept Test and Science Process Skills Test were administered to students in both groups as a pre-test. Attitude Scale towards Chemistry and Motivated Strategies for Learning Questionnaire were given to students in both groups before and after the treatment. Moreover, Solubility Equilibrium Concept Test was administered to both groups as a post-test and retention test two months after treatment. Treatment implementation continued for seven weeks. After the instruction, semi-structured interviews were conducted with six students from experimental group and six students from control group. Data were analyzed by using MANCOVA. The results revealed that LCI was more effective than the TI on students&rsquo / understanding and retention of the solubility equilibrium concepts. In addition, LCI improved students&rsquo / attitudes towards chemistry, intrinsic goal orientation, task value, self-efficacy for learning and performance, rehearsal, elaboration, organization, critical thinking, metacognitive self-regulation, time and study environment, and peer learning. Moreover, females found as more positive towards chemistry and better organization and help seeking. Furthermore, interview results indicated that students in experimental group demonstrated better scientific understanding of solubility equilibrium concepts compared to those in control group.

The Savannah River Site (SRS) deposits in the Southeastern US between 30-45 m of depth are calcium carbonate-rich, marine-skeletal, Eocene-aged sediments with varying clastic content and extensive diagenetic alteration, including meter-sized caves that coexist with brittle and hard limestone. An experimental investigation including geotechnical (P- and S-wave velocities, tensile strength, porosity) and geochemical (EDS, XRD, SEM, N2-adsorption, stable isotopes, K-Ar age dating, ICP-assisted solubility, groundwater) studies highlighted the contrast between hard and brittle limestones, their relationship with cave formation, and allowed calculation of parameters for geochemical modeling. Results demonstrate that brittle and hard limestones bear distinct geochemical signatures whereby the latter exhibits higher crystallinity, lower clastic load, and freshwater-influenced composition. Results also reveal carbonate diagenesis pathways likely driven by geologic-time seawater/freshwater cycles, microorganism-driven micritization, and freshwater micrite lithification. The second section of this investigation dealt with SRS surface soils which are largely coarse-grained and rich in iron oxides with various degrees of maturity. These soils were simulated in the laboratory using Ottawa sands that were chemically coated with goethite and hematite. Surface (SEM, AFM, N2-adsorption) and geotechnical properties (fabric, small-strain stiffness, shear strength) were investigated on the resulting "soil analog". Results indicate that iron-oxide coated sands bear distinct inherent fabric and enhanced small-strain stiffness and critical state parameters when compared to uncoated sands. Contact mechanics analyses suggest that iron oxide coatings yield an increased number of grain-to-grain contacts, higher surface roughness, and interlocking, which are believed to be responsible for the observed properties.

<p>The aim of this work was to investigate and determine central parameters that can be used to control and increase the solubility, quality and productivity of recombinant proteins. These central parameters should be applicable under the constraints of high-throughput protein production in <em>Escherichia coli.</em></p><p>The present investigation shows that alternative methods exist to improve solubility, quality and productivity of the recombinant protein. The hypothesis is that by reducing the synthesis rate of the recombinant protein, a higher quality protein should be produced. The feed rate of glucose can be used to decrease the synthesis rate of the recombinant protein.</p><p>The influence of feed rate on solubility and proteolysis was investigated using the <em>lac</em>UV5-promoter and two model proteins, Zb-MalE and Zb-MalE31. Zb-MalE31 is a mutated form of Zb-MalE that contains two different amino acids. These altered amino acids greatly affect the solubility of the protein. The soluble fraction is generally twice as high using Zb-MalE compared to Zb-MalE31. Using a low feed rate compared to high benefits the formation of the full-length soluble protein. Furthermore, by using a low feed rate, the proteolysis can be decreased. One other factor that influences the solubility is the amount of inducer used. An increase from 100 µM to 300 µM IPTG only results in more inclusion bodies being formed, the fraction of soluble protein is the same.</p><p>The quality aspect of protein production was investigated for a secreted version of Zb-MalE using two different feed rates of glucose and the maltose induced promoter P<em>malK</em>. It was shown that when the protein was secreted to the periplasm, the stringent response as well as the accumulation of acetic acid (even for high feed rates) was reduced. The stringent response and accumulation of acetic acid are factors that are known to affect the quality and quantity of recombinant proteins. Transporting the protein to the periplasm results in this case on a lower burden on the cell, which leads to less degradation products being formed when the protein is secreted to the periplasm.</p><p>Seeing the feed rate as a critical parameter, the high-throughput production would benefit from a variation in the feed rate. However, since the fed-batch technique is technically complicated for small volumes another approach is needed. <em>E.coli</em> strains that have been mutated to create an internal growth limitation that simulate fed-batch were cultivated in batch and were compared to the parent strain. It was shown that the growth rate and acetic acid formation was comparable to the parent strain in fed-batch. Furthermore it was shown that a higher cell mass was reached using one of the mutants when the cells were cultivated for as long time as possible. The higher cell mass can be used to reach a higher total productivity.</p>