Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xi, 110 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 105-110).

No description available.

This dissertation describes the theoretical, laboratory, and astronomical spectroscopy of negative molecular ions (anions), starting with the laboratory detection of the large carbon chain anion C₆H⁻ in the radio band and its identification in the molecular envelope of the carbon star IRC+10216 and in the cold dark molecular cloud TMC-1. In IRC+10216 the identification solved the long standing problem of the unidentified series of lines with rotational constant 1377 MHz first observed by K. Kawaguchi et al. Rotational spectra of the structurally similar anions---CCH⁻, C₄H⁻, C₈H⁻, CN⁻, and C₃N⁻---have been detected in the laboratory, and three more anions---C₄H⁻, C₈H⁻, and C₃N⁻---have now been identified in space. Molecular structure calculations using the CCSD(T) method and large basis sets predicted accurately the rotational constants (B₀) and centrifugal distortion constants (D[subscript J]) of all six anions and their isotopomers, guiding laboratory searches for these species. Reported here are the radio spectra of C₄H⁻, C₆H⁻, C₈H⁻, and C₃N⁻, measured to within 0.1 ppm in the centimeter-wave band by Fourier transform microwave spectroscopy of supersonic molecular beams and in the millimeter-wave band by absorption spectroscopy of low-pressure DC discharges. The spectroscopic constants derived from these measurements are so accurate, that the rotational frequencies of the anions can be calculated to within 1 km s⁻¹, adequate for radio searches in essentially all astronomical molecular sources. Radio astronomical observations with the 100 m Green Bank Telescope (GBT) toward TMC-1 yielded detection of C₈H⁻, as well as an improved estimate of the column density of C₆H⁻. The two anions are surprisingly abundant relative to their neutral radicals: a C₆H⁻/C₆H ratio of 1.6% and a C₈H⁻/C₈H ratio of 5% was derived. Upper limits were obtained for C₄H⁻/C₄H (< 0.004%) and C₃N⁻/C₃N (< 0.8%). A survey of C₆H⁻ and the related radicals C₄H and C₆H was done with the GBT toward 24 galactic molecular sources. The C₆H⁻ ion was newly detected in two dark clouds: L1544 and L1521F; C₄H was detected in nearly all dark clouds surveyed (in six for the first time); and C₆H was newly detected in five dark clouds and a translucent cloud. The observed C₆H⁻/C₆H (1%-4%) and C₆H/C₄H (0.2%-1%) ratios suggest that C₆H⁻ may be close to detection in many other dark clouds. / text

Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / M.S.

This thesis presents a systematic scheme to determine the optimal propulsive/axial force ratio of a single-sided permanent magnet axial-flux motor (SPMAM) along with its operational constraints on both the winding currents and the speed induced voltages. According to the rotating magnetic field theory with combining the recoil line characteristics of permanent magnet and the equivalent operational magnetic circuits, appropriate projection of the stator currents to achieve an optimal ratio of the machine propulsive/axial forces has been confirmed through detailed three-dimensional finite element analysis (3-D FEA) and numerical studies. From these evaluations, a feasible operational guidance for SPMAM field oriented control (FOC) scheme realizations can be suitably provided. Finally, based on the proposed optimal scheme, a DSP-based drive system has been successfully implemented, and the desired operational strategy realization can be achieved.

An experimental investigation was carried out to examine the jet impingement and spray cooling. There are three parts in this study. The first part was investigated the effects of jet impinging positions on heat transfer from rib-roughened (square and semi-circular) channels with rotational speeds of up to 600 rpm. Results were presented for rotating number (Ro), jet impinging position, surface roughness and jet Reynolds number effects on local Nusselt numbers. The second part was studied instantaneous velocity fields for a single slot liquid microjet using MPIV. The streamwise mean velocity fields and flow evolutions with six nozzle-to-target spacing ratios of 0.86, 1, 1.2, 1.5, 2 and 3 and for eight jet Reynolds numbers Re of 50, 100, 150, 200, 250, 300, 350 and 400 were measured and calculated. The third part was investigated the flow field and heat transfer mechanism for water spray and cryogen (R-134a) spray cooling. An optical image system was used to quantify the droplet size and distribution and Laser Doppler Velocimetry (LDV) measurements to obtain the local velocity distributions. The effects of mass flow rate and average droplet velocity, and spray exit-to-target distance on the surface heat flux including the corresponding critical heat flux (CHF) were explored for R-134a which may enhance the current cryogen spray cooling (CSC) technique that assists laser therapy of dermatoses.

This dissertation addresses the generalization of rigid-body attitude kinematics, dynamics, and control to higher dimensions. A new result is developed that demonstrates the kinematic relationship between the angular velocity in N-dimensions and the derivative of the principal-rotation parameters. A new minimum-parameter description of N-dimensional orientation is directly related to the principal-rotation parameters. The mapping of arbitrary dynamical systems into N-dimensional rotations and the merits of new quasi velocities associated with the rotational motion are studied. A Lagrangian viewpoint is used to investigate the rotational dynamics of N-dimensional rigid bodies through Poincar??e??s equations. The N-dimensional, orthogonal angularvelocity components are considered as quasi velocities, creating the Hamel coefficients. Introducing a new numerical relative tensor provides a new expression for these coefficients. This allows the development of a new vector form of the generalized Euler rotational equations. An N-dimensional rigid body is defined as a system whose configuration can be completely described by an N??N proper orthogonal matrix. This matrix can be related to an N??N skew-symmetric orientation matrix. These Cayley orientation variables and the angular-velocity matrix in N-dimensions provide a new connectionbetween general mechanical-system motion and abstract higher-dimensional rigidbody rotation. The resulting representation is named the Cayley form. Several applications of this form are presented, including relating the combined attitude and orbital motion of a spacecraft to a four-dimensional rotational motion. A second example involves the attitude motion of a satellite containing three momentum wheels, which is also related to the rotation of a four-dimensional body. The control of systems using the Cayley form is also covered. The wealth of work on three-dimensional attitude control and the ability to apply the Cayley form motivates the idea of generalizing some of the three-dimensional results to Ndimensions. Some investigations for extending Lyapunov and optimal control results to N-dimensional rotations are presented, and the application of these results to dynamical systems is discussed. Finally, the nonlinearity of the Cayley form is investigated through computing the nonlinearity index for an elastic spherical pendulum. It is shown that whereas the Cayley form is mildly nonlinear, it is much less nonlinear than traditional spherical coordinates.

Thesis (Ph. D.)--University of Chicago, Dept. of Physics, 2001. / Includes bibliographical references. Also available on the Internet.

Thesis (M.S.)--Brigham Young University. Dept. of Chemical Engineering, 2003. / Includes bibliographical references (p. 69-74).

Chapter one is an overall introduction reviewing the applications of compounds possessing rotational symmetry, in particular their role as asymmetric reagents/catalysts in various reactions. The attempted syntheses of two different types of C₃-symmetric homochiral triols are described in chapter two. Unfunctionalised and functionalised triamides were synthesised from the corresponding amine and 1,3,5-benzenetricarbonyl trichloride. Unfunctionalised N-substituted 1,3,5-triazacychlohexanes (triazines) were synthesised from the corresponding amine and formaldehyde, however reactions between chiral amino alcohols and formaldehyde failed to give the desired trihydroxy triazines. Chapter three describes the syntheses of a range of unfunctionalised chiral C₃-symmetric compounds, as well as a review of C₃-symmetric systems as host molecules. The successful synthesis of a range of unfunctionalised triethrs was carried out by reacting 1,3,5-tris(bromomehyl)mesitylene with some selected terpenes and other alcohols. Their role as host molecules was investigated, however they failed to bind with any of the various metals that were used. Their asymmetric induction capabilities were also tested when one of the triethers was used as a catalyst in the Et₂Zn/aldehyde reaction. The desired alcohol was indeed isolated, however it was found by ¹H nmr of the Mosher's ester to be a reacemic mixture. In chapter four the synthesis of the unfunctionalised triethers that was described in chapter three was extended to the synthesis of C₃-symmetric triethers containing functional groups. A range of tridentate ligands were synthesised containing either amino, ester, keto or hydroxyl terminal groups. In addition to these, trihydroxy ligands containing amino linkages in place of ethereal linkages were also synthesised. From these compounds three of the trihydroxy ligands were used in complexation reactions with Sn, Ti, Si, Ni, and Cu. The reactions using Si, Ni and Cu failed to give the desired complexes. However, strong evidence was obtained for the existence of the desired Sn and Ti complexes. Once again using the Et₂Zn/aldehyde reaction preliminary asymmetric induction studies were carried out using one of the Ti complexes. The reaction showed some selectivity in favour of the R enantiomer. Chapter four also describes the syntheses of some hexadentate ligands, in particular the synthesis of a chiral C₃-symmetric hexol, a C₃-symmetric ligand containing three β keto-ester groups, and also a 1,3-diketo derivative.