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Title: Manufacture of pure cider vinegar in the United States
Creator: Schommer, J. J.
Date: 2009, 1912
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/manufactureofpur00scho
Thesis (B.S.)--Armour Institute of Technology, 1912 B.S. in Chemical Engineering, 1912

Title: The manufacture of calcium cyanamide by the use of nitrogen obtained from combustion gases
Creator: Ford, T. Celie, Dunham, Joseph L.
Date: 2009, 1909
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/manufactureofcal00ford
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaf 45

Title: The manufacture of acetphenetidin from phenol
Creator: Evans, S. R, Dougherty, G. T.
Date: 2009, 1917
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/manufactureoface00evan
Thesis (B.S.)--Armour Institute of Technology, 1917 Bibliography: leaves 30-32 B.S. in...
Show morehttp://www.archive.org/details/manufactureoface00evan
Thesis (B.S.)--Armour Institute of Technology, 1917 Bibliography: leaves 30-32 B.S. in Chemical Engineering, 1917
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Title: Modern bituminous roads and pavements
Creator: Ford, Thomas Cecil
Date: 2009, 1913
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/modernbituminous00ford
Thesis (B.S.)--Armour Institute of Technology, 1913 B.S. in Chemical Engineering, 1913

Title: A 4-Phase Flow Model for Methane Production from an Unconsolidated Hydrate Reservoir
Creator: Hinz, Deniz
Date: 2019
Description: Natural gas from hydrates is extremely abundant as an energy resource; US resource-grade hydrate deposits are estimated to be over 20 times...
Show moreNatural gas from hydrates is extremely abundant as an energy resource; US resource-grade hydrate deposits are estimated to be over 20 times the domestic proved natural gas resources, at approximately 7000 trillion cubic feet (tcf). The theoretical potential of hydrates is immense, but production testing and research remain lacking, which has led to the development of numerous hydrate production numerical simulators for consolidated porous media hydrate reservoirs. However, due to the onset of unconsolidated flow behavior upon significant hydrate dissociation, numerical models haven’t agreed well with the experimental data from the Mallik production tests. Hydrate contributes substantially to the strength of the sediment matrix, such that hydrate-bearing sediment ultimately falls apart exhibiting 4-phase unconsolidated flow behavior of gas, water, hydrate, and sand. In order to better capture the multiphase flow characteristics of gas, water, hydrate, and sand in an unconsolidated gas hydrate reservoir, we have developed a novel 4-phase flow model coupled with numerical simulation of the Mallik 2007/2008 production tests. The model is able to capture the coupled 4-phase hydrodynamics, mass transfer, and heat transfer physics inherent to the unconsolidated hydrate reservoir. Solid deformation is modeled by extending multiphase and granular flow theory to hydrate-bearing sediment. Constitutive models for the solid viscosity and solid pressure are developed to model the change in strength of the sediment as hydrate dissociates and the solid deforms. The solid viscosity is a composite of frictional contributions from the solid normal stress and cohesive contributions from the hydrate. The interphase momentum exchange between the fluid phases (gas and water) and solid phases (hydrate and sand) modeled based on a volume-averaged approach that considers the formation and closure of high-permeability volumes due to dilation and compaction of hydrate-bearing sediment as it deforms. By considering the deformation of solids and the subsequent effect on the permeability, the 4-phase simulations showed good agreement with the experimental data from the Mallik 2007/2008 production phases. The 4-phase modeling approach serves as a proof of concept for the application of granular flow theory to hydrate-bearing sediment. An unconsolidated hydrate reservoir with sustained sand production essentially behaves like a naturally fracking reservoir, exhibiting a dramatic increase in permeability induced solely by depressurization. Conversely, preventing sand production with a sand screen ultimately leads to significant throttling of the gas production rate due to the compaction and accumulation of sand at the sand screen.
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Title: Economic and Computational Methods for the Control of Uncertain Systems
Creator: Zhang, Jin
Date: 2019
Description: The Economic Linear Optimal Control (ELOC) can improve the effective use of economic and dynamic information throughout the traditional...
Show moreThe Economic Linear Optimal Control (ELOC) can improve the effective use of economic and dynamic information throughout the traditional optimization and control hierarchy. This dissertation investigates the computational procedures used to obtain a global solution to the ELOC problem. The proposed method employs the Generalized Benders Decomposition (GBD) algorithm. Compared to the previous branch and bound approach, the application of GBD to the ELOC problem will greatly improve computational performance. A technological benefit of decomposing the problem into steady-state and dynamic parts is the ability to utilize nonlinear steady-state models, since the relaxed master problem is free of SDP type constraints and can be solved using any global nonlinear programming algorithm.In order to address the issue of model/plant mismatch, the dissertation will also investigate how to handle box-type uncertainties in ELOC. We consider two methods, a robust formulation for when the uncertainty is completely unknown and a Linear Parameter Varying formulation for when uncertainty can be measured in real time. In both cases, the infinite number of conditions that need to be satisfied are reduced to a finite set of constraints. The resulting problem formulations have a similar structure to the ELOC and can be solved globally by employing the generalized Benders decomposition.Despite a high-quality control law, the ultimate performance of closed-loop systems will be dictated by the quality and limitation of hardware element. Thus, hardware selection is also investigated in the dissertation. The cost-optimal hardware selection problem has been shown to be of the Mixed Integer Convex Programming (MICP) class. While such a formulation provides a route to global optimality, use of the branch and bound search procedure has limited application to fairly small systems. In this dissertation, we illustrate that a simple reformulation of the MICP and subsequent application of the GBD algorithm will result in massive reductions in computational effort.Finally, the problems of value-optimal sensor network design (SND) for steady-state and closed-loop systems are investigated. The value-optimal SND problem has been shown to be of the nonconvex mixed integer programming class. In the dissertation, it is demonstrated after transforming into an equivalent reformation, the application of GBD algorithm will significantly reduce the computational effort.
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Title: SYNERGISTIC EFFECT OF FATTY ACIDS AND NISIN IN INHIBITING PERSISTER AND BIOFILM OF LISTERIA MONOCYTOGENES
Creator: Zhou, Jiacheng
Date: 2019
Description: A foodborne pathogen Listeria monocytogenes causes a life-threatening listeriosis in humans after eating contaminated food. The FDA-approved...
Show moreA foodborne pathogen Listeria monocytogenes causes a life-threatening listeriosis in humans after eating contaminated food. The FDA-approved antimicrobial peptide nisin has been used to prevent contamination of food product from Gram-positive pathogens including L. monocytogenes. However, the formation of biofilms and persisters (i.e., metabolically dormant bacterial population) has resulted in the failure of nisin treatment. Fatty acids, which have been known to exhibit antimicrobial activities, are widely used for therapeutics, food preservation, and agriculture. Previously, we found that two fatty acid compounds lauric acids and N-tridecanoic acids are effective in inhibiting biofilms and persister formation of Gram-negative pathogens. In this study, we investigate whether the fatty acid treatment in combination with nisin promotes inactivation of L. monocytogenes, especially biofilms and persisters. The fatty acid-only treatment reduced the level of biofilms and persisters, while nisin-only treatment resulted in the development of resistant population of L. monocytogenes ATCC19115 strain. However, the co-treatment of the fatty acid and nisin synergistically enhanced the killing of L. monocytogenes by significantly decreasing the number of survived cells and inhibiting biofilms. These results are particularly important in improving food safety in that the food-grade fatty acids can be applied to repress the occurrence of resistant mechanisms of foodborne pathogens by inhibiting biofilm and persister cell formation.
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Title: UNEQUAL GRANULAR TEMPERATURE THEORY FOR MOTION OF RED BLOOD CELLS AND PLATELETS
Creator: Aralaguppe Deepak Chandra, Vishak Chandra
Date: 2015, 2015-07
Description: Blood is a multiphase mixture of liquid plasma and solid blood cells. The primary objective of this thesis is to numerically model the motion...
Show moreBlood is a multiphase mixture of liquid plasma and solid blood cells. The primary objective of this thesis is to numerically model the motion of red blood cells and platelets in blood vessels using kinetic theory based multiphase flow transport phenomena. Many experimental observations over the years have concluded that the concentration of platelets and red blood cells vary across the radius of the blood vessel. It has been shown that shear drives the platelets towards the wall, while the red blood cells move towards the center of the blood vessel. Other studies have observed that the platelet adhesion at the walls of the vessel is strongly dependent on the wall shear rate and the concentration of red blood cells. Platelet adhesion to the walls of the vessel has been explained by various shear induced diffusion models over the past few years. The diffusion models are heavily dependent on empirical relations which do not fully explain the phenomena behind the migration. In this study we postulate the dependence of red blood cell concentration on the migration of platelets using kinetic theory. The experimentally measured motion of platelets to the wall and red blood cells to the center is explained by unequal granular temperature kinetic theory. The migration of platelets in the presence of red blood cells is caused by the high granular pressure produced by the random oscillations of the red blood cells and the dissipation of platelet random energy at the walls. At the wall the shear has the highest value. This produces a high granular pressure and temperature which drive the red blood cells towards the center. An analytical solution for the platelet concentration was derived.
M.S. in Chemical Engineering, July 2015
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Title: The chemical utilization of municipal waste
Creator: Hammond, Edward K.
Date: 2009, 1909
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/chemicalutilizat00hamm
Thesis (B.S.)--Armour Institute of Technology

Title: ELECTROCHEMICAL AND TERMAL MECHANISTIC STUDY OF BEYOND LITHIUM ION SYSTEMS: LITHIUM SULFUR AND LITHIUM OXYGEN CELLS
Creator: Seo, Jeongwook
Date: 2016, 2016-05
Description: Electrochemical and Thermal Mechanistic Study of Lithium Sulfur Cell. The thermal behavior of Li/S cells was studied using IMC in terms of...
Show moreElectrochemical and Thermal Mechanistic Study of Lithium Sulfur Cell. The thermal behavior of Li/S cells was studied using IMC in terms of reversible and irreversible heat generation. The heat generation profile was compared with the voltage profile during discharge of the cell and it was found that the trend of heat generation rate shows excellent correlation with the evolution of reaction voltage, which demonstrates that the IMC technique can be used as an useful tool to study the elementary reactions of the Li/S cell. A simple heat generation model provides reasonable agreement with the measured trends in the heat release. The resistive heat evolution that is calculated by over voltage has the largest portion of total cell heat generation (85%) after the IMC heat evolution model analysis. The qualitative agreement between the aforementioned experimental results and heat generation model yields a comprehensive picture of the elementary reaction steps in Li/S cell. The increase of cell conductivity can be expected to bring about low heat evolution during cell cycling by reducing resistive heat. Doped Sulfur as a conductive cathode is a good suggestion to improve cell heat behavior. Furthermore, better cell cycle capability is expected by using lithium metal oxide cathode composites. The thermal behavior of three cathode materials for lithium/sulfur (Li/S) cell, namely - sulfur, sulfur-LiFePO4 (S-LFP) composite and sulfur-LiV3O8 (S-LVO) composite were comparatively studied using Isothermal Micro-Calorimetry (IMC) at various rates of discharge current. A continuum model was used to calculate the reversible entropic heat and irreversible resistive heat generated over the discharge process and the model data was compared to the experimental data to elucidate these contributions to the overall heat generated. The S-LVO composite cathode was found to show the least heat generation during discharge. Further, Accelerating Rate Calorimetry (ARC) was used to study the thermal safety of these three cells. The cell with the S-LVO composite cathode was found to have the highest onset temperature for thermal runaway and also the lowest maximum self-heat rate. The combination of high capacity, long cycle life and thermal stability makes the S-LVO composite cathode a very promising material for Li/S cells Oxygen Reduction Reaction Studies using Rotating Ring Disk Electrode for Li-Air battery. The oxygen reduction reaction (ORR) studies in aqueous electrolytes have reported the following reaction mechanisms: (i) four electron reaction, (ii) two electron reaction and (iii) one electron chemical reaction. On the other hand, the aprotic ORR literature has no reports of four electrons and two electrons transfer reaction. The kinetics of ORR on the cathode was carried out using rotating ring disk electrode (RRDE) technique. The first step of ORR which produces the superoxide radical was investigated on glassy carbon (GC) disk in 0.1 M tetrabutylammonium bis-(trifluoromethane)imide (TBATFSI)/dimethoxyethane (DME). One-electron reduction to the superoxide radical was founded in the linear sweep voltammetry (LSV) analysis. Further, ORR to produce LiO2 and Li2O2 was carried in bis(trifluoromethane)sulfonimide-lithium(LITFSI)/DME on porous carbon coated glassy carbon electrode disk. The reaction kinetic rate on the porous carbon was calculated using the Li-O2 ORR mechanism model. The kinetic rate was compared with the kinetic rate of glassy carbon electrode. The non-aqueous system has several advantages compared to the aqueous system such as high operation voltage and non-reactive electrolyte with Li+. However this system has some critical problems such as low solubility of Li2O2 and High charge over potential. One attempted solution for these disadvantages of the non-aqueous system was to carry out water addition into the solvent which was expected to produce highly soluble LiOH with lower overpotential. Small amount of Water, 0.5 wt% added into 0.1 M LiTFSI/DME and 1 wt% added in the 0.2 M TBATFSI/DME electrolyte, showed great electrochemical performance with lower onset potential and overvoltage. The kinetics of ORR study for the non-aqueous and aqueous hybrid system was carried out using RRDE technique. Koutecky-Levich plot and Tafel slope analysis indicated two electron transfer reaction on the hydrated 0.1 M LiTFSI/DME. This hydrated system can be expected to double energy storage by two electron transfer ORR for Li-O2 Cell.
Ph.D. in Chemical Engineeering, May 2016
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Title: Chemical analysis of engineering alloys
Creator: Wilsnack, G. C., Patrick, W. W
Date: 2009, 1912
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/chemicalanalysis00wils
Thesis (B.S.)--Armour Institute of Technology, 1912 B.S. in Chemical Engineering, 1912

Title: INVENTORY CREEP PHENOMENON IN PROCESS SCHEDULING
Creator: Aleissa, Yazeed Muqbel
Date: 2016, 2016-05
Description: This work discuss the inventory creep phenomenon that occurs in production processes. Most production process use inventory to store their...
Show moreThis work discuss the inventory creep phenomenon that occurs in production processes. Most production process use inventory to store their products for max- imizing profit. When planning and scheduling control methods were applied, these processes encountered this phenomenon at the end of the controlled horizon. We applied the economic model protective control on a production process example and demonstrate the effect the inventory creep in open-loop and closed-loop solutions. An approach is developed to negate this problem by implementing a novel terminal constraints that showed a promising results in the overall performance of the process.
M.S. in Chemical Engineering, May 2016
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Title: CLONING, EXPRESSION, PURIFICATION AND STRUCTURE DETERMINATION OF PEANUT ALLERGEN ARA H 5
Creator: Wang, Yang
Date: 2012-11-21, 2012-12
Description: In our study, the peanut allergen Ara h 5 was cloned from raw peanut mRNA. The cDNA of the gene was then introduced into different expression...
Show moreIn our study, the peanut allergen Ara h 5 was cloned from raw peanut mRNA. The cDNA of the gene was then introduced into different expression vectors for protein expression in different E.coli strains. Recombinant protein expression was very successful with useful amounts of soluble protein produced. Fast protein liquid chromatography was used to purify the recombinant Ara h 5. High purity protein was subjected to crystallization screen and good quality crystals were harvested. Several crystallographic data sets were collected at a synchrotron X-ray beam line. The three-dimensional structure of the peanut profilin Ara h 5 was determined to 1.10Å resolution. The purified protein and the purification methods can be used in future research on the protein’s allergenecity, cross-reactivity and allergy immunotherapies. The high resolution structure was compared with the structures of homologous allergens and the putative epitopes was displayed on the allergen structure to evaluate their possible legitimacies. In the future, the Ara h 5 structure could be very valuable in studies of allergenecity and in the design of future immunotherapies.
PH.D in Biology, December 2012
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Title: THERMO-RESPONSIVE HYDROGELS FOR INTRAVITREAL INJECTION AND BIOMOLECULE RELEASE
Creator: Drapala, Pawel
Date: 2011-04-20, 2011-05
Description: In this dissertation, we develop an injectable polymer system to enable localized and prolonged release of therapeutic biomolecules for...
Show moreIn this dissertation, we develop an injectable polymer system to enable localized and prolonged release of therapeutic biomolecules for improved treatment of Age-Related Macular Degeneration (AMD). Thermo-responsive hydrogels derived from N-isopropylacrylamide (NIPAAm) and cross-linked with poly(ethylene glycol) (PEG) poly(L-Lactic acid) (PLLA) copolymer were synthesized via free-radical polymerization. These materials were investigated for (a) phase change behavior, (b) in-vitro degradation, (c) capacity for controlled drug delivery, and (d) biocompatibility. The volume-phase transition temperature (VPTT) of the PNIPAAm-co-PEG- b-PLLA hydrogels was adjusted using hydrophilic and hydrophobic moieties so that it is ca. 33 C. These hydrogels did not initially show evidence of degradation at 37 C due to physical cross-links of collapsed PNIPAAm. Only after addition of glutathione chain transfer agents (CTA)s to the precursor did the collapsed hydrogels become fully soluble at at 37 C. CTAs signi cantly a ected the release kinetics of biomolecules; addition of 1.0 mg/mL glutathione to 3 mM cross-linker accelerated hydrogel degradation, resulting in 100 % release in less than 2 days. This work also explored the e ect of PEGylation in order to tether biomolecules to the polymer matrix. It was demonstrated that non-site-speci c PEGylation can postpone the burst release of solutes (up to 10 days in hydrogels with 0.5 mg/mL glutathione). Cell viability assays showed that at least two 20-minute bu er extraction steps were needed to remove cytotoxic elements from the hydrogels. Clinically-used therapeutic biomolecules Lucentis® and Avastin® were demonstrated to be both stable and bioactive after release form PNIPAAm-co-PEG-b-PLLA hydrogels. The thermo-responsive hydrogels presented here o er a promising platform for the localized delivery of proteins such as recombinant antibodies.
Ph.D. in Chemical and Biological Engineering, May 2011
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Title: Building and operating a cider vinegar plant
Creator: Schommer, John Joseph
Date: 2009, 1920
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/buildingoperatin00scho
Thesis (B.S.)--Armour Institute of Technology

Title: MODELING GLUCOSE-INSULIN DYNAMICS AND AUTOMATED BLOOD GLUCOSE REGULATION IN PATIENTS WITH TYPE 1 DIABETES
Creator: Oruklu, Meriyan
Date: 2012-11-06, 2012-12
Description: Estimation of future glucose concentrations is a crucial task for diabetes management. Predicted glucose values can be used for early...
Show moreEstimation of future glucose concentrations is a crucial task for diabetes management. Predicted glucose values can be used for early hypoglycemic/hyperglycemic alarms or for adjustment of insulin amount/rate. In the first part of this thesis, reliable subject-specific glucose concentration prediction models are developed using a patient’s continuous glucose monitoring (CGM) data. CGM technologies provide glucose readings at a high frequency and consequently detailed insight into a patient’s glucose variation. Time-series analyses are utilized to develop low-order linear models from a patient’s own CGM data. Glucose prediction models are integrated with recursive identification and change detection methods, which enable dynamical adaptation of the model to inter-/intra-subject variability and glycemic disturbances. Two separate patient data sets collected under hospitalized (disturbance-free) and normal daily life conditions are used to validate the univariate glucose prediction algorithm developed. Prediction performance is evaluated in terms of prediction error metrics and Clarke error grid analysis (CG-EGA). The long-term complications of diabetes can be reduced by controlling the blood glucose concentrations within normoglycemic limits. In the second part of this thesis, the subject-specific modeling algorithm developed in part one is integrated with a control algorithm for closing the glucose regulation loop for patients with type 1 diabetes. An adaptive control algorithm is developed to keep a patient’s glucose concentrations within normoglycemic range and dynamically respond to glycemic challenges with automated subcutaneous insulin infusion. A model-based control strategy is used to calculate the required insulin infusion rate, while the model parameters are recursively identified at each sampling step. The closed-loop algorithm is designed for the subcutaneous route for both glucose sensing and insulin delivery. xii It accounts for the slow insulin absorption from the adipose tissue and the time-delay between blood and subcutaneous glucose concentrations. The performance of the control algorithm developed is demonstrated on two simulated patient populations to provide effective blood glucose regulation in response to multiple meal challenges with a simultaneous challenge on a patient’s insulin sensitivity. Physical activity and emotional stimuli such as stress are known to have a significant effect on a patient’s whole-body fuel metabolism. In the third part of this thesis, the univariate time-series models developed from recent glucose concentration history are extended to include additional information on a patient’s physical and emotional condition. Physiological measurements from a multi-sensor body monitor are used to supplement a patient’s CGM data and develop multivariate glucose prediction models. The prediction performance of the multivariate algorithm developed is evaluated on data collected from patients with type 2 diabetes, and a real life implementation of the algorithm is demonstrated for early (i.e., 30 min in advance) hypoglycemia detection. Finally, the control algorithm developed in part two is extended to utilize the glucose profiles predicted by the multivariate patient model. The multivariate closedloop algorithm is tested with two clinical experiments performed on a patient with type 1 diabetes during a high intensity exercise followed by a carbohydrate-rich meal challenge. The algorithm acquires the patient’s CGM and armband (body monitor) data every 10 min, and accordingly calculates the required basal insulin infusion rate. Insulin is administered in a fully automated manner without any food or activity announcements (e.g., no information on meal/exercise size or time). None of the algorithms developed in this thesis require any patient specific tailoring or prior experimental data before implementation. They are also designed to function in a fully automated manner and do not require any disturbance announcexiii ments or manual inputs. Therefore, they are good candidates for installation on a portable ambulatory device used in a patient’s home environment for his/her diabetes management.
PH.D in Chemical and Biological Engineering, December 2012
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Title: MULTI-AGENT MODELING OF TISSUE GROWTH AND ANGIOGENESIS WITH HIGH PERFORMANCE COMPUTING
Creator: Bayrak, Elif Seyma
Date: 2015, 2015-07
Description: Tissue engineering emerged as a result of the high demand of transplant organ and tissues in spite of low number of donors. Rapid and stable...
Show moreTissue engineering emerged as a result of the high demand of transplant organ and tissues in spite of low number of donors. Rapid and stable vascularization still presents the major challenge for three-dimensional functional tissues. Bone is a highly vascularized tissue. Regeneration of vascularized bone tissue from osteogenic cells in biodegradable scaffolds is strongly affected by the interplay between scaffold properties, chemical cues and precursor cells. The number of variables that contribute to the formation of engineered tissues present a challenging optimization problem that cannot be addressed with the experimentation alone. Complex system such as vascularized tissue growth can benefit from properly developed computational models. Computational models can help us understand interactions between the various parts of the complex systems, imagine all possible outcomes of a specific event, explain reasons and causes and forecast future trajectories. Agent-based modeling (ABM) is a powerful modeling and simulation technique that builds a structure from bottom-up to model and understand systems comprised of autonomous, interacting entities. ABM is a natural choice to model biological system that is comprised of many interacting cells. ABM possesses great advantages including simulating of each individuals behavior, holding their history, allowing them to adapt to dynamic conditions and learn through simple to complex algorithms. One main concern of the modelers is the computational heaviness of ABMs that limits the use of this technique in real time optimization, monitoring and control applications. Discovering the full potential of ABM in biological system with huge population size depend on the computational power available.A multi layer agent based model to simulate vascular bone regeneration in degradable porous hydrogels is developed both for personal computer (PC) environment and high performance computing (HPC) platforms. The personal computer (PC) version of this model is built upon the angiogenesis model that was previously developed by Arsun Artel and Hamidreza Mehdizadeh. This work is focused on development of bone tissue growth layer while considering the interactions and improving the existing layers and uses the parallel processing paradigm for running tissue growth more efficiently and more quickly. This model aims to help investigating and understanding the interactions between soluble factors, scaffolds and cells, and finding the optimal biomaterial structure and soluble cues to maximize vascularization and differentiation to bone tissue.
Ph.D. in Chemical Engineering, July 2015
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Title: By-products from wool washing
Creator: Butterman, Samuel, Marx, Victor E
Date: 2009, 1916
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/byproductsfromwo00butt
Thesis (B.S.)--Armour Institute of Technology; Includes folded leaves in back pocket

Title: By-products from garbage
Creator: Mease, A. J., Goorskey, N. J., Botts, T. E.
Date: 2009, 1917
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/byproductsfromga00meas
Thesis (B.S.)--Armour Institute of Technology

Title: MULTIFUNCTIONAL ELECTROCATALYST SUPPORTS AND ELECTROCATALYSTS FOR ELECTROCHEMICAL ENERGY CONVERSION
Creator: Kumar, Amod
Date: 2014, 2014-07
Description: Polymer electrolyte fuel cell (PEFC) technology has several underlying problems (lifetime, reliability and cost) that need to be resolved as a...
Show morePolymer electrolyte fuel cell (PEFC) technology has several underlying problems (lifetime, reliability and cost) that need to be resolved as a prerequisite for large-scale commercialization. Amongst these, the lifetime issue is regarded as critical. From the perspective of durability, the current state-of-the-art electrocatalyst, viz. platinum (Pt) supported on high surface area carbon, suffers substantial degradation during fuel cell operation. A key pathway for electrocatalyst degradation is the corrosion of the carbon support. During fuel cell startup and shutdown in automotive applications, the cathode potential undergoes excursions of up to 1.6 V. At these high potentials, the carbon corrosion reaction is significantly accelerated, leading to irreversible carbon loss at the electrode. The best way to eliminate the issue of support corrosion in PEFCs is to develop alternate corrosion-resistant catalyst supports. This dissertation investigates (i) mixed oxides of silica (SiO2) and ruthenia (RuO2) and (ii) tantalum modified titanium oxide (Ta0.3Ti0.7O2) for use as corrosion-resistant electrocatalyst supports in PEFCs, especially for the automotive sector, using detailed microstructure characterization and electrochemical evaluation, including two carefully chosen accelerated stress tests (startstop cycling to simulate fuel cell vehicle start-up and shut-down, and load cycling to simulate full-load to no-load transitions in the vehicle during operation). RuO2–SiO2 (0.5:0.5) displayed outstanding electrochemical stability upon exposure to rigorous accelerated potential cycling tests that mimic automotive drive cycles. The Pt/RuO2–SiO2 (0.5:0.5) electrocatalyst yielded a mass activity of 50 mA/mgPt and an area specific activity of 156.3 μA/cm2 at 0.9 V vs. RHE when tested in a fuel cell operating at 80 ºC and 75% RH. A 20 wt.% Pt/Ta0.3Ti0.7O2 catalyst was compared in terms of activity and stability against benchmark Pt/C catalysts. The importance of a corrosion resistant support in a PEFC was demonstrated by monitoring performance loss during start-stop cycling and load cycling; while load cycling did not cause a performance drop, the corrosion-resistant nature of the Ta0.3Ti0.7O2 support helped prevent catastrophic fuel cell failure observed in carbon-supported catalysts during start-stop cycling. Corrosion-resistant electrode materials can not only be applied to PEFCs but can also be extended to other electrochemical energy storage and conversion devices such as redox-flow batteries and electrolyzers. The results of this work also indicate suitable strategies for incorporation of other possible dopants (such as Nb, W and Zr) within TiO2, as well as the use of other metal oxides (such as SnO2 and HfO2) as alternative catalyst supports.
Ph.D. in Chemical Engineering, July 2014
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