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(21 - 40 of 188)
Pages
- Title
- The synthetic manufacture of phenol
- Creator
- Parrot, Raymond D.
- Date
- 2009, 1919
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/syntheticmanufac00parr
Thesis (B.S.)--Armour Institute of Technology
- Title
- A study of a suction gas producer
- Creator
- Hoffman, Balthasar
- Date
- 2009, 1907
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/studyofsuctionga00hoff
Thesis (B.S.)--Armour Institute of Technology
- Title
- TOWARDS THE EXACT CALCULATIONS OF THE FREE ENERGY FOR ENTANGLED SEMIFLEXIBLE POLYMER CHAIN
- Creator
- Pilyugina, Ekaterina
- Date
- 2015, 2015-05
- Description
-
This work consists of two separate projects unified by the idea to extend the Discrete Slip-Link Model, which has been being successfully...
Show moreThis work consists of two separate projects unified by the idea to extend the Discrete Slip-Link Model, which has been being successfully developed in this group to predict rheological behavior of entangled flexible polymers, to new applications. The first project was dedicated to application of the Discrete Slip-Link Model to dielectric relaxation in order to simultaneously predict linear rheology and dielectric relaxation experiments of entangled polyisoprenes. Linear monodisperse, linear bidisperse and star-branched monodisperse systems were studied. It was found that all circumstances save one are well described. Namely, dilute long chains in a sea of short chains can be predicted rheologically, but dielectric relaxation data show a reduction in the relaxation time of long chains greater than that predicted by either the DSM or the expected Rouse motion. The second project was focused on the derivation of the exact free energy expression for semiflexible chains in the presence of entanglements in order to implement the DSM for semiflexible polymers. The special cases of chains with one, two and three strands are examined. An additional implementation of obtained results for one and two strands to buckling instability was performed. It is believed that in two dimensional case the critical buckling force is increased by thermal fluctuations in comparison to classical Euler buckling. However, how the critical buckling force is influenced by thermal fluctuations in three dimensions remains unclear. Some research groups calculate the critical buckling force approximately and conclude that, in opposite to 2D case, in 3D the force is decreased by thermal fluctuations. In this work the critical buckling force for semiflexible chain under compression was calculated exactly. It was shown that thermal fluctuations significantly increase the critical force over classical Euler buckling force in both two and three dimensions.
Ph.D. in Chemical Engineering, May 2015
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- Title
- CO2 CAPTURE AND HYDROGEN PRODUCTION IN SORBENT ENHANCED WATER-GAS SHIFT (SEWGS) PROCESS WITH REGENERABLE SOLID SORBENT
- Creator
- Zarghami Khanehsar, Shahin
- Date
- 2015, 2015-07
- Description
-
Carbon dioxide emission from fossil fuel combustion and its impact on global warming is one of the most critical environmental issues nowadays...
Show moreCarbon dioxide emission from fossil fuel combustion and its impact on global warming is one of the most critical environmental issues nowadays. Coal as a main source of produce energy is the most CO2-intensive fossil fuel. Advanced power generation processes that use gasification technology, such as Integrated Gasification Combined Cycle (IGCC), which offer higher efficiency, are among the leading contenders for power generation in the 21st century. In an IGCC process, because of high pressure, carbon dioxide in the fuel gas is at higher concentration, which can be captured and sequestered at lower costs. Utilization of regenerable MgO-based sorbents has been shown to be an effective method for capturing CO2 from gasification-based processes at elevated temperatures and pressures (i.e. p > 20 atm and 330° < T < 450°C). Low cost MgO based sorbent can be prepared through modification of natural dolomite. The reactivity of the sorbent in carbonation/regeneration cycles has a significant impact on the economics of the proposed regenerable process. Although the sorbent can be regenerated in successive cycles, the sorbent reactivity and capacity gradually decline during the cyclic process. Therefore, it is crucial to develop a better understanding on the role of the key parameters affecting the reactivity of the sorbent going through the cyclic carbonation/regeneration process. In this work, a systematic study on the sorbent preparation parameters (i.e., calcination temperature, calcination duration, calcination temperature ramp, potassium concentration, impregnation duration, drying temperature, re-calcination temperature, and re-calcination duration) was conducted to understand the effect of each parameter on the overall capacity and reactivity of the sorbent. The concentration of potassium additive (as carbonation reaction promoter) has the most significant effect on the reactivity of the sorbent and the optimum K/Mg molar ratio appears to be in the range of 0.1-0.16. The reactivity of the sorbent toward carbon dioxide at various operating conditions (i.e. temperature, CO2 concentration and steam concentration) was experimentally evaluated. The presence of steam significantly improves the reactivity of the sorbent which is attributed to formation of more favorable pore structure as well as the existence of a parallel carbonation reaction pathway involving the formation of a transient MgO.H2O* compound. The optimum carbonation reaction temperature in the presence of steam is around 380˚C. The effect of cycling on CO2 capture capacity of MgO-based sorbent was also experimentally investigated in this work. Series of carbonation/regeneration cycles (up to 25) have been carried out in a dispersed bed reactor to determine the effect of various variables on long term durability of the sorbent. The gradual loss of CO2 sorption capacity appears to be mainly due to loss potassium (a carbonation reaction promoter) in the cyclic process. Durability of the sorbents improves in the presence of steam, which is likely due to the favorable changes in the pore structure of the sorbents. A kinetic model was developed to fit the reactivity curves obtained from the dispersed bed tests at different operating conditions which was needed to predict the sorbent/catalyst performance in the regenerative process. Model parameters were defined and discussed for each of the operating conditions, as well as dispersed bed cyclic tests. Furthermore, the thermal behavior and the kinetics of partial decomposition of dolomite were studied in a dispersed-bed reactor to improve the reactivity of the sorbent. The microstructure and the nature of the solid products were found to be strongly dependent on the CO2 partial pressure near the reacting interface and on the decomposition temperature. A significant increase in the rate of the dolomite decomposition reaction was found in the presence of steam. Steam improves the kinetics of decomposition, modifies the radial distribution of the pores; and improves the connectivity of the pores inside the dolomite particles, which decreases the diffusion resistance of produced carbon dioxide inside the particle. A shrinking core model with variable product layer diffusivity was used to fit the experimental data and determine the kinetic parameters of the dolomite decomposition reaction. The results indicate that transport of CO2 across the reacting interface in the porous particle was the main limiting factor in the decomposition reaction at the experimental conditions investigated. A lab-scaled high-pressure/high-temperature packed-bed reactor was utilized to evaluate the performance of the sorbent in simultaneous water-gas shift reaction and sorbent carbonation environment. It was shown that the CO2 in the coal gas can be removed by regenerable MgO-based sorbents at temperatures around 350°C, and the CO2 removal can shift WGS reaction to enhance hydrogen production. Therefore, Sorbent Enhanced Water-Gas-Shift (SEWGS) can result in much higher hydrogen production without lowering the temperature, leading to higher overall process efficiency.
Ph.D. in Chemical Engineering, July 2015
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- Title
- A study of the corrosion of locomotive boiler tubes
- Creator
- Congdon, Charles C.
- Date
- 2009, 1915
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/studyofcorrosion00cong
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaves 36-37
- Title
- INVESTIGATION OF THE EFFICACY OF REACTIVE OXYGEN SPECIES GENERATED BY BOVINE AORTIC ENDOTHELIAL CELLS FOR INITIATING FREE-RADICAL POLYMERIZATION
- Creator
- Lu, Chenlin
- Date
- 2013, 2013-12
- Description
-
Reactive oxygen species are reported to be generated by bovine aortic endothelial cells during ischemia followed by reperfusion. This...
Show moreReactive oxygen species are reported to be generated by bovine aortic endothelial cells during ischemia followed by reperfusion. This biological response, believed to be the cause of post-ischemic reperfusion injury, inspired us to investigate the possibility of coupling it with the initiation of free-radical polymerization to produce polymer hydrogels for cell encapsulation. In this work, the generation of reactive oxygen species during ischemia and reperfusion was examined by fluorescence detection and the feasibility of initiating free-radical polymerization by generated reactive oxygen species was investigated in two sets of experiments. The generation of reactive oxygen species by bovine aortic endothelial cells when subjected to anoxia followed by reoxygenation was investigated in both attached and suspended cells. Both intracellular and extracellular generations of ROS appeared to occur in the experiments of attached cells. Cell viability experiments demonstrated that the generation of ROS was sufficient to cause cell damage and death. The feasibility of initiating free-radical polymerization by reactive oxygen species generated by bovine aortic endothelial cells subjected to anoxia followed by reoxygenation was investigated in two sets of experiments. One set involved the linear polymerization of NVP which allowed us to quantify the extent of polymerization and characterization of the weight conversion of PVP polymer. The other set involved the formation of PEGDA hydrogels which were characterized by imaging and staining methods. To our knowledge this is the first evidence of cell induced polymerization initiated by reactive oxygen species and gelation which can be used for a variety of biomedical applications.
M.S. in Chemical and Biological Engineering, December 2013
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- Title
- A study of the "cracking" of petroleum
- Creator
- Heritage, Clark Cable, Hook, Frank William.
- Date
- 2009, 1914
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/studyofcrackingo00heri
Thesis (B.S.)--Armour Institute of Technology, 1914 B.S. in Chemical Engineering, 1914
- Title
- A study of the effect of temperature and pressure on the carbonation of water
- Creator
- Marx, Walter L
- Date
- 2009, 1916
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/studyofeffectoft00marx
Thesis (B.S.)--Armour Institute of Technology, 1916 Bibliography: leaf 40 B.S. in...
Show morehttp://www.archive.org/details/studyofeffectoft00marx
Thesis (B.S.)--Armour Institute of Technology, 1916 Bibliography: leaf 40 B.S. in Chemical Engineering, 1916
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- Title
- EVALUATION OF COXIELLA BURNETII NINE MILE PHASE II INACTIVATION IN WHOLE MILK AFTER THERMAL TREATMENT BY INTEGRATED CELL CULTURE-PCR ASSAY
- Creator
- Ma, Songchuan
- Date
- 2013-04-30, 2013-05
- Description
-
Coxiella burnetii, the etiologic agent of Q fever, is a Gram-negative, obligate intracellular coccobacillus, which has been used as the...
Show moreCoxiella burnetii, the etiologic agent of Q fever, is a Gram-negative, obligate intracellular coccobacillus, which has been used as the reference organism for defining milk pasteurization conditions. A developed Integrated Cell Culture-PCR (ICC-PCR) assay may be helpful for evaluating C. burnetii inactivation by thermal process in whole milk products. The purpose of this research was to characterize and optimize an ICCPCR assay in whole milk and evaluate this assay by thermal process. Coxiella burnetii was diluted into whole milk from FDA stock and treated by thermal process. Samples were sealed in glass vials and placed in ice-water to obtain a consistent starting temperature. Cooled vials were heated in a shaking waterbath at 60 °C, 62 °C and 64 °C in for various times. Thermally treated samples were diluted by RPMI+1% FBS and inoculated on Vero cell culture monolayers with PBS, incubated for 48 hours to infect the Vero cells, and then incubated for another 9 days to allow propagation. The propagated C. burnetii mix was subjected to freeze-thaw followed by DNA extraction with Autogen DNA Tissue Kit by using Quickgene Mini80. Extracted DNA was amplified by using TaqMan-MGB based qPCR targeting published primers for the IS1111a transposase gene to verify C. burnetii growth. For detection limit determination, serial dilutions of C. burnetii were mixed independently in whole milk and 1% FBS+RPMI. The mix was overlaid on confluent Vero cells for 2 days and 11 days. The DNA extractions were followed using DNA tissue kit by Quickgene Mini80 and PCR. At least duplicate trials using 3 replicates per trial were completed for each time/temperature condition.
M.S. in Food Safety and Technology, May 2013
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- Title
- MODEL-BASED EXPLORATION OF THE FEASIBILITY OF CREATING MULTIPLE PROPERTY GRADIENT IN CROSSLINKED POLYMER FILMS IN CONTROLLED LIVING POLYMERIZATION
- Creator
- Qin, Zikai
- Date
- 2014, 2014-05
- Description
-
The functional gradient materials have been widely used in chemical engineering, biomedical engineering and tissue engineering since they have...
Show moreThe functional gradient materials have been widely used in chemical engineering, biomedical engineering and tissue engineering since they have been reported because of their admirable mechanical, physical and chemical properties. Several traditional methods of synthesis gradient materials are known to all. Here we introduced a new mathematical model of designing and producing crosslinked polymeric films with target multiple gradients. We derive our model from batch reactor system and explore how each condition of the system affects the gradient of the polymer film. Then we extend to semi-batch reactor to control the gradient in crosslink density and set up different strategies to make the target multiple gradient crosslink density accomplish. With any given target gradient crosslinked polymer film, we can make an exact similar film in our model.
M.S. in Chemical Engineering, May 2014
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- Title
- PEGYLATION OF FIBRONECTIN AND ITS FUNCTIONAL DOMAINS: EFFECT ON STABILITY AND BIOLOGICAL ACTIVITY
- Creator
- Zhang, Chen
- Date
- 2013, 2013-07
- Description
-
Delayed wound healing in many chronic wounds has been linked to the lack of extracellular matrix (ECM) support and the degradation of...
Show moreDelayed wound healing in many chronic wounds has been linked to the lack of extracellular matrix (ECM) support and the degradation of fibronectin (FN) by an abnormally high protease level. The ECM is important in wound healing because it provides physical and chemical cues that direct tissue growth and development. FN is a key ECM protein that attracts and binds different molecules and cells and thereby supports biological responses associated with wound healing. The goal of my study is two fold: (1) To create an ECM analogue based on a composite of polyethylene glycol (PEG) hydrogels and FN binding domains and (2) To stabilize FN against proteolytic degradation by conjugating it to PEG. To address the first goal, I used Michael addition chemistry to covalently link the cell-binding domain of FN, III9−10, to PEG diacrylate and cross-linked the conjugate to PEG hydrogels. The conjugation of PEG to III9−10 was through cysteines in the affinity tag Glutathione S Transferase (GST). The conjugate of GST-III9−10 and PEG was characterized by: (i) Circular dichroism studies to determine secondary structure, (ii) Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to determine molecular weight, and (iii) Ellmans reagent to determine the efficiency of PEG conjugation to GST-III9−10. The conjugate of PEG and GST-III9−10 had comparable secondary structure to GST-III9−10. SDS-PAGE studies showed that up to three PEG molecules were attached to one GST-III9−10 molecule. The efficiency of PEG conjugation was greater than 90% and occurred within 30 minutes after PEG diacrylate addition. Adhesion assays were used as a metric of biological activity. These assays demonstrated that on a molar basis cell adhesion and spreading were significantly higher on PEG hydrogels with GST-III9−10 than those with the commonly used arginine-glycine-aspartic acid (RGD) peptide. Scaffold rigidity is an important biological cues that influence xi cell responses. However, a comparative study of rigidity on GST-III9−10 and RGD functionalized PEG hydrogels demonstrated that differences in rigidity could not account for differences in cell adhesion and spreading between RGD and GST-III9−10 functionalized PEG hydrogels. Thus as ECM analogues, GST-III9−10 functionalized hydrogels provide more robust biochemical cues than RGD functionalized hydrogels. Studies of PEG hydrogel composites with mixtures of III9−10 and a fibronectin binding domain demonstrated that biological responses of adhesion and spreading and extracellular matrix assembly could be controlled by varying the ratio of these two domains and the rigidity of the PEG hydrogels. FN was stabilized against proteolytic degradation by covalent attaching it to PEG or by PEGylating it. FN was first isolated from human plasma by gelatin affinity chromatography and then PEGylated using two methods. The first method is to PEGylate human plasma fibronectin (HPFN) at cysteine residues with 3.4 kDa PEG diacrylate. The second method is to PEGylate HPFN at lysine residues on the surface with 2-10 kDa PEG Succinimidyl carboxy methyl esters. Cysteine PEGylation of HPFN was first carried out because cysteines are concentrated in the amino- terminus of HPFN which leaves two-thirds of the molecule, including the cell-binding domain, unperturbed. PEGylation of HPFN on cysteines resulted in a molecule that supported cell adhesion, spreading, focal adhesion formation and cell migration in a comparable manner to native HPFN. Moreover, PEGylated HPFN was incorporated into the ECM in a similar manner to native HPFN when present in the culture media but not when coated on a surface indicating that PEGylation on cysteines modified some biological activity of HPFN. Additionally, HPFN PEGylated by this manner could not bind denatured collagen or gelatin. The gelatin-binding domain is at the site of cysteine PEGylation. The second approach for PEGylation of HPFN was through lysine residues xii on the surface of the protein. This approach was used because it targeted different amino acid residues in FN. The length of PEG and extent of PEGylation have been reported to influence biological activity of proteins. In the second approach, both PEG length and extent were varied. HPFN completely PEGylated on lysines residues was significantly more proteolytically stable than native HPFN but had reduced cell attachment and spreading. Furthermore, cell spreading and attachment on surfaces conjugated with this lysine PEGylated HPFN decreased with increasing PEG length. Partially PEGylated HPFN was synthesized by masking the cell and gelatin binding domains during PEGylation. The partially PEGylated HPFN supported cell adhesion and spreading in a similar manner to native HPFN and was more proteolytically stable. For the partially PEGylated HPFN, the size of PEG poly had no significant influence on the attachment and spreading of cells. These studies are the first attempt by any laboratory to stabilize FN against proteolytic degradation while retaining activity and show the feasibility of this approach as a potential therapeutic approach. The work presented here shows a two-prong approach by which the problem of ECM degradation and deficiency chronic wound healing can be addressed. The first approach for addressing ECM deficiency is through a scaffold design methodology. The novelty of the scaffold approach is that it uses the cell-binding domains of FN instead of the often-used RGD peptide. I demonstrate that a PEG hydrogel with the cell-binding domain produces a more robust biological response in cells than a PEG hydrogel with the RGD peptide. I also demonstrate that varying different functional domains of fibronectin can be used to controllably stimulate multiple biological responses. The second approach demonstrates a method by which FN, a key ECM protein, is stabilized against proteolytic degradation without perturbing its activity. These studies of creating PEG-FN conjugates are the first of their kind. Collectively, the data that I present in this thesis will lead to novel therapeutic methods for treating chronic wounds.
PH.D in Chemical Engineering, December 2012
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- Title
- The study of the formation of chromates
- Creator
- Kaplon, H., Schiffman, H. M.
- Date
- 2009, 1921
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/studyofformation00kapl
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaf 30
- Title
- AGENT-BASED MODELING OF ANGIOGENESIS: EXPLORATION OF THE EFFECTS OF VEGF DELIVERY STRATEGIES ON PROMOTING ANGIOGENESIS
- Creator
- Xiao, Nan
- Date
- 2015, 2015-05
- Description
-
This is a dissertation about three-dimensional agent-based modeling (ABM) of angiogenesis within porous scaffold. Tissue engineering...
Show moreThis is a dissertation about three-dimensional agent-based modeling (ABM) of angiogenesis within porous scaffold. Tissue engineering technology provides great benefits for humanity in maintaining healthy tissue formation and disease rehabilitation. However, biomedical experiments, especially animal experiments, are very costly, timeconsuming and high technological level of equipment required. The computational modeling can provide an efficient alternative to biomedical experiments in strategy design and assist clinical research. To simulate the angiogenesis process, an agent-based model was developed using java-based Repast toolkit. The purpose of this research is to explore the effects of different Vascular Endothelial Growth Factor (VEGF) delivery methods in promoting angiogenesis. The work here includes four parts: a) model verification by comparing simulation results with experimental results; b) exploration of different VEGF delivery methods by changing total dose and release rate; c) exploration of the effects of prevascularized strategies; d) development of a tissue cell VEGF secretion model. The simulation results showed that: angiogenesis can be promoted by increasing VEGF total dose or decreasing releasing rate; prevascularized scaffolds can improve new vascular network formation and result in better invasion depth; pre-seeded tissue cells in the scaffold can provide a continuous source of VEGF and promote angiogenesis. This ABM can provide a good reference for the design of biomedical applications.
M.S. in Chemical Engineering, May 2015
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- Title
- EFFECT OF REACTANT CONCENTRATIONS AND AGING EFFECT IN THE SYNTHESIS OF SILVER NANORODS
- Creator
- Wang, Guan
- Date
- 2016, 2016-05
- Description
-
In the recent years, anisotropic metallic nanoparticles have drawn much attention because of their unique optical properties. Particularly,...
Show moreIn the recent years, anisotropic metallic nanoparticles have drawn much attention because of their unique optical properties. Particularly, gold and silver nanorods show great potential in extensive applications such as health care, food storage, drug delivery, biosensor, and cancer treatment. Among a variety of nanorods synthesis methods, the seed-mediated growth approach stands out due to its mild and convenient experimental conditions. However, there exist two defects of this method, the poor reproducibility and low yield of nanorods. In order to create nanoparticle systems of reproducible quality in high yields, a deeper understanding of the mechanism of nanorods formation as well as identifying the more important variables is necessary. In this study, the original seed-mediated growth method has been modified to promote the reproducibility and yield of nanorods. Effects of CTAB concentration and ages of growth solution have been investigated in the nanorods formation process. The results suggest that a high concentration of CTAB is not necessary for the growth process and the age of growth solution can affect the optical performance of nanorods. In a brief survey on the stability property of nanorods, it shows that the degradation rate decreases with increasing concentrations of CTAB.
M.S. in Chemical Engineering, May 2016
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- Title
- MODELING, CONTROL, AND DESIGN OF HYBRID FUEL CELL VEHICLES
- Creator
- Ahmed, Syed
- Date
- 2011-12, 2011-12
- Description
-
The Polymer Electrolyte Membrane Fuel Cell (PEMFC) has been projected to be the fuel cell of choice for future automotive applications. Among...
Show moreThe Polymer Electrolyte Membrane Fuel Cell (PEMFC) has been projected to be the fuel cell of choice for future automotive applications. Among the challenging aspects of this application is maintaining highly efficient operation of the fuel cell. The key component of the PEMFC, the Nafion Membrane, can reach two critical states: drying and flooding. In drying, high resistance prevents normal operation of the fuel cell. In flooding, reactants are prevented from reaching reaction sites and there is a reduction of performance of the fuel cell. To address the first point, a spatially distributed along the plane membrane model was developed and tested with proportional-integral control of voltage and temperature. To analyze the occurrence of severe and frequent changes in power demand, a model aimed at mimicking the load expected in a fuel cell vehicle, including a DC motor, DC-DC converters and a rechargeable battery for peak-shaving and regenerative braking was developed. The model includes rotational and translational inertia as well as a simple wind resistance model for a vehicle. In contrast to simple lab-focused loads where load impendence is directly manipulated, the manipulated variable within this load is the DC-DC converter gain. Based on this model a control system architecture was developed consisting of a number of low level regulatory loops, a power distributor for peak-shaving and finally a high level loop for tracking vehicle speed. After understanding the load demands to a fuel cell vehicle with only a battery, the issue of multiple energy storage technologies is addressed. Designing a vehicle with these technologies poses an optimization problem. A high-level model of a fuel cell vehicle with two storage technologies, a battery and super-capacitor was developed. The model accounted for the constraints of each component and a drive cycle characterized the power demand. An economic-based optimization problem xv was posed whereas its objective was to minimize the capital cost of the system, while meeting power demand and keeping the technologies within their constraints. The result of the optimization provided a controller from which a high-level power coordination unit can be developed for the fuel cell vehicle.
Ph.D. in Chemical Engineering, December 2011
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- Title
- Some observations on the baking test as commercially applied to wheat and flour
- Creator
- Pirrie, Peter Gustave
- Date
- 2009, 1913
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/someobservations00pirr
Thesis (B.S.)--Armour Institute of Technology; Includes index
- Title
- UNDERSTANDING THE MEMBRANE ACTIVITY OF ACYL LYSINE OLIGOMERS
- Creator
- Lingaraju, Mahesh
- Date
- 2012-07-10, 2012-07
- Description
-
In the past two decades, Antimicrobial peptides (AMPs) have attracted considerable interest because of their potential therapeutic use as...
Show moreIn the past two decades, Antimicrobial peptides (AMPs) have attracted considerable interest because of their potential therapeutic use as antibiotics, antivirals, and antitumoural drugs. However, there are a number of serious challenges on the way toward bringing AMPs onto the market which include their rapid in vivo degradation, high production costs, reduced activity in physiological conditions, etc. To overcome these problems and yet to capitalize on the immense potential of AMPs, extensive efforts to develop their non-natural mimics have been recently made. A better understanding of the structure-activity relationships of AMPs is essential to the creation of a successful peptidomimetic compound. It has been widely accepted that AMPs kill pathogens by disrupting the cell membrane or invading the cytoplasm and inhibiting core metabolic functions. Thus, the pathogenic membrane plays a crucial role either as an immediate target or as a barrier that must be traversed. Herein, we have investigated the role of charge and hydrophobicity in the interplay between membrane-active molecules (Oligomers of acyl lysine) and model bacterial or host cell membranes using constant-pressure insertion assays, synchrotron X-ray reflectivity (XR) and grazing incident-angle X-ray diffraction (GIXD). The outer surface of a membrane was approximated by a planar lipid monolayer at the air-liquid interface, whose composition was modified in accordance with the cell being modelled. The presented results have helped us to arrive at a general mechanism by which the OAKs seem to interact with lipids which is strongly dependent upon the charge density of the monolayer, charge and hydrophilicity of the molecule and presence of freely accessible hydrophobic regions. The results indicate the molecules fail to interact with the acyl chains when they poorly negotiate with the head group or when they lack accessible hydrophobic regions. Overall, presented results advance current understanding of the mechanism of action of flexible AMP mimics on bacterial membranes and will no doubt aid in the rational design and optimization of non-natural mimics of antimicrobial peptides that will be effective against multidrug resistant bacteria and cancer cells. Nevertheless, future work is required to further understand the critical factors leading to potent anti-infective activity of antimicrobials.
M.S. in Molecular Biochemistry and Biophysics, July 2012
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- Title
- Study of the chemical and physical properties of molding sands
- Creator
- Woldenberg, Maximilian
- Date
- 2009, 1906
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/studyofchemicalp00wold
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaves 26-29
- Title
- Test of a new method for the fixation of atmospheric nitrogen
- Creator
- Buttner, William C., Knaus, Peter J.
- Date
- 2009, 1913
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/testofnewmethodf00butt
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaf 37
- Title
- A study of resorcinol production
- Creator
- Bernstein, Joseph M., Vogt, Emil G.
- Date
- 2009, 1920
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/studyofresorcino00bern
Thesis (B.S.)--Armour Institute of Technology