Browsing by Subject "Thermodynamic"
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Item Design and synthesis of conformationally constrained Src SH2 ligands for protein–ligand thermodynamic evaluation(2016-08) Gravenstreter, Alicia Nicole; Martin, Stephen F.; Keatinge-Clay, Adrian TPredicting how small structural changes will impact the thermodynamics of binding a small molecule to a protein represents a major challenge in the fields of drug design and biological recognition. The tetrapeptide, pYEEI, binds to the sarcoma (Src) SH2 domain in both hot spot and non-hot spot locations, presenting an opportunity to examine how ligand preorganization at a non-hot spot region will affect the thermodynamics of binding. Incorporation of a cyclopropane to constrain both the backbone and side-chain of the isoleucine residue of the native pYEEI ligand will allow us to preorganize the ligand in its binding conformation for thermodynamic evaluation. Several attempts towards the preparation of the constrained ligand will be discussed as well as preparation of a flexible control ligand for direct comparison.Item Dynamic subdivided relative humidity model of a polymer electrolyte membrane fuel cell(2013-05) Headley, Alexander John; Chen, Dongmei, Ph. D.The development of a control-oriented dynamic relative humidity model for a polymer electrolyte membrane (PEM) fuel cell stack is presented. This model is integrated with a first law based thermal model, which tracks energy flow within four defined control volumes in the fuel cell; the cathode channel, anode channel, coolant channel, and fuel cell stack body. Energy and mass conservation equations are developed for each control volume. On top of mass conservation, electro-drag and osmosis models were also implemented within the model to account for the major modes of vapor transfer through the membrane between the anode and cathode. Requisite alterations to the thermal model as well as mass flow rate calculations are also discussed. Initially, the model utilized a single lumped control volume for the calculation of all values each channel (anode and cathode). This lumped value method is computationally inexpensive, and makes the model optimal for control design. However, investigation of the mass-based Biot number showed the need for greater granularity along the length of the channels to properly capture the relative humidity dynamics. In order to improve the resolution of the model, while still minimizing the computation expense, the model was subdivided into a series of lumped value models. The cathode channel was the point of focus as it is the major concern from a controls perspective. This method captures the proper trends found in far more complex CFD models, while still maintaining a quick calculation time. Different levels are subdivision (3 and 6 submodels) are investigated, and the differences discussed. Particularly, temperature range, relative humidity range, the effect on the modeled voltage, and calculation time are compared. This control-oriented model is low order and based on lumped parameters, which makes the computational expense low. Formulation of this model enables the development of control algorithms to achieve optimal thermal and water management.