Browsing by Subject "Calcium carbonate"
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Item Item Biomolecule interactions on calcium carbonate and stoichiometrically similar biomedical, optical and electronic materials(2004) Gooch, Erin Elaine; Belcher, Angela M.A combinatorial approach has been successfully used to characterize peptides that bind to four different surfaces of CaCO3 and six different oxide substrates that are chemically and stoichiometrically similar to CaCO3. A standard screening and a single substrate screening method were employed. Both methods used a bacteriophage combinatorial library with a complexity of 109 different random sequences. While geological (104) calcite screenings do not seem to show strong consensus, peptides screened against geological aragonite exhibit extraordinary consensus. Overall, peptides screened against aragonite were highly basic. Peptides screened against (110) geological aragonite show [LAIVG]P[WF][RKH] and triple [RKH] patterns. The most significant binding peptide, A21 (LPPWKHKTSGVA) was found in 4 separate screenings. The (110) geological aragonite sequences are highly enriched in prolines. Coincidently, peptides screened against the optical material LiNbO3 +Z show patterns similar to those found in the aragonite screenings. Other substrates that did not exhibit strong consensus include powdered LiNbO3, powdered BaTiO3, powdered PbTiO3, single crystal LiNbO3 –Z, and hydroxyapatite. A database and analysis program was written to catalog and evaluate the statistical significance of the many sequences. One peptide that was determined to be extremely significant in binding to aragonite, A20 (LPKWQERQMLSA), was modeled using umbrella sampling molecular dynamics techniques as well as analyzed by NMR. It was determined that there is a good probability that the peptide’s conformation is helical, but it is able to introconvert between α-helical, 3-10 helical and extended conformations fast enough that a stable secondary structure is not detectable by NMR. Engineered phage were constructed to display these significant peptides on the pVIII surface, increasing the expression level and the long range order in the hopes of building an aragonite nucleation surface. Hybrid organic-inorganic materials were grown on the phage resulting in a mixture of the three forms of CaCO3: calcite, vaterite, and aragonite. In addition, hybrid materials were grown on the optical waveguide material LiNbO3. Doubly engineered phage were shown to bind preferentially to the LiNbO3 +Z surface through the interaction of the A1 displayed peptide as well as nucleate semiconducting ZnS particles via the A7 peptide selected previously against ZnS.Item Item Degradation of pedogenic calcretes in West Texas(Texas Tech University, 2003-08) Hirmas, Daniel RNot availableItem Distribution and petrography of calcrete zones, southern High Plains, New Mexico and Texas(Texas Tech University, 1981-12) Ries, Gaila VawnNot availableItem Effect of soil texture and calcium carbonate on laboratory-generated dust emissions from SW North America(2013-05) Mockford, Tom; Lee, Jeffrey; Perry, Gad; Zobeck, Ted M.; Bateman, MarkUnderstanding the controls of mineral dust emissions and their particle size distributions during wind-erosion events is critical as dust particles play a significant impact in shaping the earth’s climate. It has been suggested that emission rates and particle size distributions are independent of soil chemistry and soil texture. In this study, 37 samples of wind-erodible surface soils from the High Plains regions of Texas, New Mexico and Colorado were analyzed by the Lubbock Dust Generation, Analysis and Sampling System (LDGASS) and a Beckman-Coulter particle multisizer. The LDGASS created dust emissions in a controlled laboratory setting using a rotating arm, which allows particle collisions. The emitted dust was transferred to a chamber where particulate matter concentration was recorded using a DataRam and MiniVol filter and dust particle size distribution was recorded using a GRIMM particle analyzer. Particle size analysis was also determined from samples deposited on the Mini-Vol filters using a Beckman-Coulter particle multisizer. Soil textures of source samples ranged from sands and sandy loams to clays and silts. Results suggest that total dust emissions increased with increasing soil clay and silt content and decreased with increasing sand content. Particle size distribution analysis showed a similar relationship; soils with high silt content produced the widest range of dust particle sizes and the smallest dust particles. Sand grains produce the largest dust particles. The chemical control on dust emissions by calcium carbonate content is also discussed.Item Effects of particle-size distribution, organic matter and calcium carbonate on water retention of Texas High Plains soils(Texas Tech University, 1985-05) Meng, Tan PiowThe overall objective of the research program was to provide data that will allow the prediction of the probable effectiveness of precipitation when deep plowing has altered the texture of the plow layer.Item Removal of calcium carbonate scaling by carbon dioxide injection(Texas Tech University, 1990-12) Thomas, Gary LeeNot availableItem Thermal decomposition of calcium carbonate(Texas Tech University, 1969-08) Gordon, James LaughlandNOT AVAILABLEItem Toward the development of robust self-healing concrete using vegetative microorganisms(2015-05) Williams, Sarah Lynn; Ferron, Raissa D.; Kirisits, Mary JoRobust self-healing concrete, which requires less maintenance and repair throughout its service life than ordinary concrete, can be used for the development of sustainable infrastructure. Li and Herbert stated that a true robust self-healing concrete should meet six critical robustness criteria; the self-healing mechanism should 1. possess a long shelf life comparable to the service life of the structure; 2. be pervasive throughout the material; 3. exhibit good quality as indicated by the percentage of recovery provided; 4. be reliable; 5. be versatile in various environmental conditions; 6. be repeatable over the service life of the structure; Although many approaches can be used to promote self-healing in cement-based materials, use of biomineralization (the process by which organisms stimulate the formation of minerals) for this purpose has generated considerable interest. Previous research on biomineralization, specifically microbial-induced calcium carbonate precipitation, suggested that this process can improve durability and remediate cracks in concrete. This thesis presents the results of a multifaceted research program undertaken to evaluate the robustness of microbial concrete containing vegetative Sporosarcina pasteurii. Specifically, the criteria of versatility and quality were assessed. Versatility was evaluated by examining the influence of environmental factors on the polymorph selection process of calcium carbonate precipitated due to the activity of S. pasteurii, and it was determined that calcium concentration and overall ionic strength impacted morphology as did pH and substrate mineralogy. Another aspect of versatility that was addressed was the ability of vegetative S. pasteurii to remain viable and metabolically active when subjected to harsh conditions that might occur inside concrete including heat, high pH, and nutrient depletion. Quality was assessed by comparing properties of biogenic calcium carbonate and synthetic calcium carbonate, and it was determined that the former exhibited greater kinetic and thermodynamic stability than the latter. Quality was further examined by determining the ability of biomineralization to heal flexural cracks in mortar and provide strength recovery. Finally, the chemical constituents of the growth medium for S. pasteurii were optimized to mitigate severe retardation in cement hydration kinetics that has been observed when vegetative bacteria suspended in growth medium are added to cement, which improved the feasibility of microbial concrete.