Feet on the potential energy surface, head in the pie clouds (open access)

Feet on the potential energy surface, head in the pie clouds

This work presents explorations of the potential energy surface of clusters of atoms and of the interactions between molecules. First, structures of small aluminum clusters are examined and classified as ground states, transition states, or higher-order saddle points. Subsequently, the focus shifts to dispersion-dominated π-π interactions when the potential energy surfaces of benzene, substituted benzene, and pyridine dimers are explored. Because DNA nucleotide bases can be thought of as substituted heterocycles, a natural extension of the substituted benzene and pyridine investigations is to model paired nucleotide bases. Finally, the success of the dispersion studies inspires the development of an extension to the computational method used, which will enable the dispersion energy to be modeled – and the potential energy surface explored – in additional chemical systems. The effective fragment potential (EFP) method is described, as well as various quantum mechanical methods. An ab inito quantum mechanical study of 13-atom aluminum clusters is described. EFP studies of aromatic dimers are reported in which dispersion energy makes a significant contribution to the attraction between monomers. Theory and code development toward a means of computing dispersion energy in mixed ab inito-EFP systems are described.
Date: July 12, 2012
Creator: Smith, Quentin
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Wind prediction with multiple guide stars reduces tomographic errors and expands MOAO field of regard (open access)

Wind prediction with multiple guide stars reduces tomographic errors and expands MOAO field of regard

None
Date: July 12, 2012
Creator: Ammons, S. M.; Poyneer, L.; Gavel, D.; Kupke, R.; Max, C. E. & Johnson, L.
Object Type: Article
System: The UNT Digital Library
Attempted transverse impedance measurement in RHIC (open access)

Attempted transverse impedance measurement in RHIC

N/A
Date: July 12, 2012
Creator: M., Blaskiewicz & Montag, C.
Object Type: Report
System: The UNT Digital Library
Brayton Power Conversion System (open access)

Brayton Power Conversion System

Brayton Power Conversion System
Date: July 12, 2012
Creator: Kesseli, James
Object Type: Report
System: The UNT Digital Library
A REVIEW OF RECENT IMPURITY MEASUREMENTS OF LANL MATERIAL (open access)

A REVIEW OF RECENT IMPURITY MEASUREMENTS OF LANL MATERIAL

The Applied Computational Engineering and Statistics (ACES) group of the Savannah River National Laboratory (SRNL) was asked to review recent measurements performed by the Los Alamos National Laboratory (LANL) on material from that facility that is being considered for processing through the Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF) at the Savannah River Site (SRS). There are specification limits for impurities in the feed to the MOX facility: a maximum limit and an exceptional limit. The limits for an impurity apply to the population of concentration values for that impurity for a class of material that is to be processed through MOX. For the purposes of this report, these limits were defined as follows. The concentration of an elemental impurity, expressed as micrograms of the element per gram of plutonium ({micro}g/g Pu), is to be no more than the maximum limit for that element for 98% of the material coming through MOX; that is, 98% of the material processed at MOX is to have a concentration of the given element less than the maximum limit. In addition, the concentration for a given element is to be no more than the exceptional limit for that element for 99.9% of the material …
Date: July 12, 2012
Creator: Edwards, T.
Object Type: Report
System: The UNT Digital Library
Paraxial WKB Method Applied to the Lower Hybrid Wave Propagation (open access)

Paraxial WKB Method Applied to the Lower Hybrid Wave Propagation

The paraxial WKB (pWKB) approximation, also called beam tracing method, has been employed in order to study the propagation of lower hybrid (LH) waves in a tokamak plasma. Analogous to the well-know ray tracing method, this approach reduces Maxwell's equations to a set of ordinary differential equations, while, in addition, retains the effects of the finite beam cross-section, and, thus, the effects of diffraction. A new code, LHBEAM (Lower Hybrid BEAM tracing), is presented, which solves the pWKB equations in tokamak geometry for arbitrary launching conditions and for analytic and experimental plasma equilibria. In addition, LHBEAM includes linear electron Landau damping for the evaluation of the absorbed power density and the reconstruction of the wave electric field in both the physical and Fourier space. Illustrative LHBEAM calculations are presented along with a comparison with the ray tracing code GENRAY and the full wave solver TORIC-LH.
Date: July 12, 2012
Creator: Bertelli, N.; Poli, E.; Harvey, R.; Wright, J. C.; Bonoli, P. T.; Phillips, C. K. et al.
Object Type: Report
System: The UNT Digital Library
Final Technical Report – CMS FAST OPTICAL CALORIMETRY (open access)

Final Technical Report – CMS FAST OPTICAL CALORIMETRY

This is the final report of CMS FAST OPTICAL CALORIMETRY, a grant to Fairfield University for development, construction, installation and operation of the forward calorimeter on CMS, and for upgrades of the forward and endcap calorimeters for higher luminosity and radiation damage amelioration.
Date: July 12, 2012
Creator: Winn, David R
Object Type: Report
System: The UNT Digital Library
Microarcsecond relative astrometry from the ground with a diffractive pupil (open access)

Microarcsecond relative astrometry from the ground with a diffractive pupil

None
Date: July 12, 2012
Creator: Ammons, S. Mark; Bendek, Eduardo A.; Guyon, Olivier; Macintosh, Bruce & Savransky, Dmitry
Object Type: Article
System: The UNT Digital Library
Environmental Restoration Disposal Facility Lessons Learned (open access)

Environmental Restoration Disposal Facility Lessons Learned

The purpose of lessons learned is to identify insight gained during a project – successes or failures – that can be applied on future projects. Lessons learned can contribute to the overall success of a project by building on approaches that have worked well and avoiding previous mistakes. Below are examples of lessons learned during ERDF’s ARRA-funded expansion project.
Date: July 12, 2012
Creator: Caulfield, R.
Object Type: Report
System: The UNT Digital Library
Recovery Act: Training Program Development for Commercial Building Equipment Technicians (open access)

Recovery Act: Training Program Development for Commercial Building Equipment Technicians

The overall goal of this project has been to develop curricula, certification requirements, and accreditation standards for training on energy efficient practices and technologies for commercial building technicians. These training products will advance industry expertise towards net-zero energy commercial building goals and will result in a substantial reduction in energy use. The ultimate objective is to develop a workforce that can bring existing commercial buildings up to their energy performance potential and ensure that new commercial buildings do not fall below their expected optimal level of performance. Commercial building equipment technicians participating in this training program will learn how to best operate commercial buildings to ensure they reach their expected energy performance level. The training is a combination of classroom, online and on-site lessons. The Texas Engineering Extension Service (TEEX) developed curricula using subject matter and adult learning experts to ensure the training meets certification requirements and accreditation standards for training these technicians. The training targets a specific climate zone to meets the needs, specialized expertise, and perspectives of the commercial building equipment technicians in that zone. The combination of efficient operations and advanced design will improve the internal built environment of a commercial building by increasing comfort and safety, …
Date: July 12, 2012
Creator: Glameyer, Leah
Object Type: Report
System: The UNT Digital Library