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Getting the Wheels Turning: Assessing Strategies for Financing & Advancing Mass Transit Infrastructure in the 21st-Century
This thesis explores several strategies for advancing the growth of mass transit infrastructure in the United States. This thesis finds that public-private partnerships (P3), design-build delivery systems, and value capture tools like tax-increment financing (TIF) all have potential for improving the feasibility of financing and constructing transportation infrastructure. However, they do carry some drawbacks and must be utilized in an appropriate context. While the three tools may address different components of a project and are not necessarily applicable in the same situation, this thesis finds that design-build carries the least risk and should be incorporated more broadly
Advanced thermoplastic resins, phase 1
Eight thermoplastic polyimide resin systems were evaluated as composite matrix materials. Two resins were selected for more extensive mechanical testing and both were versions of LaRC-TPI (Langley Research Center - Thermoplastic Polyimide). One resin was made with LaRC-TPI and contained 2 weight percent of a di(amic acid) dopant as a melt flow aid. The second system was a 1:1 slurry of semicrystalline LaRC-TPI powder in a polyimidesulfone resin diglyme solution. The LaRC-TPI powder melts during processing and increases the melt flow of the resin. Testing included dynamic mechanical analysis, tension and compression testing, and compression-after-impact testing. The test results demonstrated that the LaRC-TPI resins have very good properties compared to other thermoplastics, and that they are promising matrix materials for advanced composite structures
Heterotic-string amplitudes at one loop: modular graph forms and relations to open strings
We investigate one-loop four-point scattering of non-abelian gauge bosons in heterotic string theory and identify new connections with the corresponding open-string amplitude. In the low-energy expansion of the heterotic-string amplitude, the integrals over torus punctures are systematically evaluated in terms of modular graph forms, certain non-holomorphic modular forms. For a specific torus integral, the modular graph forms in the low-energy expansion are related to the elliptic multiple zeta values from the analogous open-string integrations over cylinder boundaries. The detailed correspondence between these modular graph forms and elliptic multiple zeta values supports a recent proposal for an elliptic generalization of the single-valued map at genus zero
Conformational Preferences of 3-(Dimethylazinoyl)propanoic Acid as a Function of pH and Solvent; Intermolecular versus Intramolecular Hydrogen Bonding
The conformational equilibrium of 3-(dimethylazinoyl)propanoic acid (DMAPA, azinoyl = N^+(O^−) has a weak pH-dependence in D_2O, with a slight preference for trans in alkaline solutions. The acid ionization constants of the protonated amine oxide and carboxylic functional groups as determined by NMR spectroscopy were 7.9 × 10^(−4) and 6.3 × 10^(−6), respectively. The corresponding value of K_1/K_2 of 1.3 × 10^2 is not deemed large enough to provide experimental NMR evidence for a significant degree of intramolecular hydrogen bonding in D_2O. Conformational preferences of DMAPA are mostly close to statistical (gauche/trans = 2/1) in other protic solvents, e.g., alcohols. However, the un-ionized form of DMAPA appears to be strongly intramolecularly hydrogen-bonded and gauche in aprotic solvents
Contumacious Beasts: A Story of Two Diastylidae (Cumacea) from Arctic Waters
A full description of the subadult male holotype of the diastylid Ektonodiastylis robusta, new genus, new species, is presented, as well as of the adult male and adult female of E. nimia. Ektonodiastylis nimia is transferred from Brachydiastylis to Ektonodiastylis. The family definition of Diastylidae is expanded. The implications of this expansion on the systematics of the Cumacea in general, and Diastylidae and Gynodiastylidae in particular, are discussed
Wide range and tunable linear TMR sensor using two exchange pinned electrodes
A magnetic tunnel junction sensor is proposed, with both the detection and
the reference layers pinned by IrMn. Using the differences in the blocking
temperatures of the IrMn films with different thicknesses, crossed anisotropies
can be induced between the detection and the reference electrodes. The pinning
of the sensing electrode ensures a linear and reversible output. It also allows
tuning both the sensitivity and the linear range of the sensor. The authors
show that the sensitivity varies linearly with the ferromagnetic thickness of
the detection electrode. It is demonstrated that an increased thickness leads
to a rise of sensitivity and a reduction of the operating range
Hedge Fund Boards and the Market for Independent Directors
We provide the first examination of hedge fund boards and their directors. The majority of directorships are held by extremely busy independent directors. These directors are sought after by funds because they have more reputational capital at stake, making them independent and credible monitors whose presence can certify fund quality to investors. Busy independent directors are more likely to be hired by high quality funds, and their departure from the board is associated with investor withdrawals. Moreover, funds with busy independent directors are less likely to commit fraud, abuse discretionary liquidity restrictions, or engage in performance-based risk shifting
Coulomb-U and magnetic moment collapse in -Pu
The around-the-mean-field version of the LDA+U method is applied to
investigate electron correlation effects in -Pu. It yields a
non-magnetic ground state of Pu, and provides a good agreement with
experimental equilibrium volume, bulk modulus and explains important features
of the photoelectron spectra
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