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Effects of grit roughness and pitch oscillations on the NACA 4415 airfoil (open access)

Effects of grit roughness and pitch oscillations on the NACA 4415 airfoil

A NACA 4415 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory 3 x 5 subsonic wind tunnel under steady state and unsteady conditions. The test defined baseline conditions for steady state angles of attack from {minus}10{degree} to +40{degree} and examined unsteady behavior by oscillating the model about its pitch axis for three mean angles, three frequencies, and two amplitudes. For all cases, Reynolds numbers of 0.75, 1, 1.25, and 1.5 million were used. In addition, these were repeated after the application of leading edge grit roughness (LEGR) to determine contamination effects on the airfoil performance. Steady state results of the NACA 4415 testing at Reynolds number of 1.25 million showed a baseline maximum lift coefficient of 1.30 at 12.3{degree} angle of attack. The application of LEGR reduced the maximum lift coefficient by 20% and increased the 0.0090 minimum drag coefficient value by 62%. The zero lift pitching moment of {minus}0.0967 showed a 13% reduction in magnitude to {minus}0.0842 with LEGR applied. Data were also obtained for two pitch oscillation amplitudes: {+-}5.5{degree} and {+-}10{degree}. The larger amplitude consistently gave a higher maximum lift coefficient than the smaller amplitude, and both unsteady maximum lift coefficients were …
Date: July 1, 1996
Creator: Hoffmann, M. J.; Reuss Ramsay, R. & Gregorek, G. M.
Object Type: Report
System: The UNT Digital Library
Effects of grit roughness and pitch oscillations on the S814 airfoil (open access)

Effects of grit roughness and pitch oscillations on the S814 airfoil

Horizontal-axis wind turbine rotors experience unsteady aerodynamics when the rotor is yawed, when rotor blades pass through the support tower wake, and when the wind is gusting. An understanding of this unsteady behavior is necessary to assist in the design of new rotor airfoils. The rotors also experience performance degradation due to surface roughness. These surface irregularities are due to the accumulation of insect debris, ice, and/or the aging process. Wind tunnel studies that examine both the steady and unsteady behavior of airfoils can help define pertinent flow phenomena, and the resultant data can also be used to validate analytical computer codes. An S814 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) 3 X 5 subsonic wind tunnel (3 X 5) under steady flow with both stationary model conditions and pitch oscillations. To study the extent of performance loss due to surface roughness, a leading edge grit roughness pattern (LEGR) was used to simulate leading edge contamination. After baseline cases were completed, the LEGR was applied for both steady state and model pitch oscillation cases. The Reynolds numbers for steady state conditions were 0.75, 1, 1.25 and 1.5 million, while the angle of …
Date: July 1, 1996
Creator: Janiszewska, J. M.; Ramsay, R. Reuss; Hoffmann, M. J. & Gregorek, G. M.
Object Type: Report
System: The UNT Digital Library
Control of interface fracture in silicon nitride ceramics: influence of different rare earth elements (open access)

Control of interface fracture in silicon nitride ceramics: influence of different rare earth elements

The toughness of self-reinforced silicon nitride ceramics is improved by enhancing crack deflection and crack bridging mechanisms. Both mechanisms rely on the interfacial debonding process between the elongated {Beta}-Si{sub 3}N{sub 4} grains and the intergranular amorphous phases. The various sintering additives used for densification may influence the interfacial debonding process by modifying the thermal and mechanical properties of the intergranular glasses, which will result in different residual thermal expansion mismatch stresses; and the atomic bonding structure across the {Beta}-Si{sub 3}N{sub 4} glass interface. Earlier studies indicated that self-reinforced silicon nitrides sintered with different rare earth additives and/or different Y{sub 2}O{sub 3}:AI{sub 2}0{sub 3} ratios could exhibit different fracture behavior that varied from intergranular to transgranular fracture. No studies have been conducted to investigate the influence of sintering additives on the interfacial fracture in silicon nitride ceramics. Because of the complexity of the material system and the extremely small scale, it is difficult to conduct quantitative analyses on the chemistry and stress states of the intergranular glass phases and to relate the results to the bulk properties. The influence of different sintering additives on the interfacial fracture behavior is assessed using model systems in which {Beta}-Si{sub 3}N{sub 4}whiskers are embedded in …
Date: October 1, 1996
Creator: Sun, E. Y.; Becher, P. F.; Waters, S. B.; Hsueh, Chun-Hway; Plucknett, K. P. & Hoffmann, M. J.
Object Type: Article
System: The UNT Digital Library
Valve studies: Hydrogen fluoride monitoring of UF{sub 6} cylinder valves (open access)

Valve studies: Hydrogen fluoride monitoring of UF{sub 6} cylinder valves

Uranium hexafluoride (UF{sub 6}) cylinder valves have, like the cylinders, been in use and/or storage for periods ranging from 15 to 44 years. Visual inspection of the cylinders has shown that the extent of corrosion and the overall cylinder condition varies widely throughout the storage yards. One area of concern is the integrity of the cylinder valves. Visual inspection has found deposits which have been identified as radioactive material on or near the valves. These deposits suggest leakage of UF{sub 6} and may indicate valve degradation; however, these deposits may simply be residual material from cylinder filling operations.
Date: August 1, 1996
Creator: Leedy, R. R.; Ellis, A. R.; Hoffmann, D. P.; Marsh, G. C.; Melton, R. C.; Phifer, D. W., Jr. et al.
Object Type: Report
System: The UNT Digital Library
Speciation of Fe in ambient aerosol and cloudwater (open access)

Speciation of Fe in ambient aerosol and cloudwater

Atmospheric iron (Fe) is thought to play an important role in cloudwater chemistry (e.g., S(IV) oxidation, oxidant production, etc.), and is also an important source of Fe to certain regions of the worlds oceans where Fe is believed to be a rate-limiting nutrient for primary productivity. This thesis focuses on understanding the chemistry, speciation and abundance of Fe in cloudwater and aerosol in the troposphere, through observations of Fe speciation in the cloudwater and aerosol samples collected over the continental United States and the Arabian Sea. Different chemical species of atmospheric Fe were measured in aerosol and cloudwater samples to help assess the role of Fe in cloudwater chemistry.
Date: August 15, 1996
Creator: Siefert, L.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Ranger (San Antonio, Tex.), Vol. 71, No. 12, Ed. 1 Friday, January 26, 1996 (open access)

The Ranger (San Antonio, Tex.), Vol. 71, No. 12, Ed. 1 Friday, January 26, 1996

Weekly student newspaper from San Antonio College in San Antonio, Texas that includes campus news along with advertising.
Date: January 26, 1996
Creator: San Antonio College
Object Type: Newspaper
System: The Portal to Texas History
The Ranger (San Antonio, Tex.), Vol. 72, No. 3, Ed. 1 Friday, September 27, 1996 (open access)

The Ranger (San Antonio, Tex.), Vol. 72, No. 3, Ed. 1 Friday, September 27, 1996

Weekly student newspaper from San Antonio College in San Antonio, Texas that includes campus news along with advertising.
Date: September 27, 1996
Creator: San Antonio College
Object Type: Newspaper
System: The Portal to Texas History
The Rattler (San Antonio, Tex.), Vol. 82, No. 11, Ed. 1 Wednesday, March 6, 1996 (open access)

The Rattler (San Antonio, Tex.), Vol. 82, No. 11, Ed. 1 Wednesday, March 6, 1996

Biweekly student newspaper from St. Mary's University in San Antonio, Texas that includes campus news along with advertising.
Date: March 6, 1996
Creator: St. Mary's University (San Antonio, Tex.)
Object Type: Newspaper
System: The Portal to Texas History
DIII-D research operations. Annual report to the US Department of Energy, October 1, 1994--September 30, 1995 (open access)

DIII-D research operations. Annual report to the US Department of Energy, October 1, 1994--September 30, 1995

The DIII-D research program funded by the U.S. Department of Energy (DOE) is aimed at developing the knowledge base for an economically and environmentally attractive energy source for the nation and the world. The DIII-D program mission is to advance fusion energy science understanding and predictive capability and improve the tokamak concept. The DIII-D scientific objectives are: (1) Advance understanding of fusion plasma physics and contribute to the physics base of ITER through extensive experiment and theory iteration in the following areas of fusion science - Magnetohydrodynamic (MHD) stability - Plasma turbulence and transport - Wave-particle interactions - Boundary physics plasma neutral interaction (2) Utilize scientific understanding in an integrated manner to show the tokamak potential to be - More compact by increasing plasma stability and confinement to increase the fusion power density ({Beta}{tau}) - Steady-state through disruption control, handling of divertor heat and particle loads and current drive (3) Acquire understanding and experience with environmentally attractive low activation material in an operating tokamak. This report contains the research conducted over the past year in search of these scientific objectives.
Date: September 1, 1996
Creator: unknown
Object Type: Report
System: The UNT Digital Library
The Baytown Sun (Baytown, Tex.), Vol. 74, No. 240, Ed. 1 Tuesday, August 6, 1996 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 74, No. 240, Ed. 1 Tuesday, August 6, 1996

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: August 6, 1996
Creator: Dobbs, Gary
Object Type: Newspaper
System: The Portal to Texas History
The Kernel Polynomial Method for non-orthogonal electronic structure calculations (open access)

The Kernel Polynomial Method for non-orthogonal electronic structure calculations

The Kernel Polynomial Method (KPM) has been successfully applied to tight-binding electronic structure calculations as an O(N) method. Here we extend this method to nonorthogonal basis sets with a sparse overlap matrix S and a sparse Hamiltonian H. Since the KPM method utilizes matrix vector multiplications it is necessary to apply S{sup -1} H onto a vector. The multiplication of S{sup -1} is performed using a preconditioned conjugate gradient method and does not involve the explicit inversion of S. Hence the method scales the same way as the original KPM method, i.e. O(N), although there is an overhead due to the additional conjugate gradient part. We show an application of this method to defects in a titanate/platinum interface and to a large scale electronic structure calculation of amorphous diamond.
Date: October 1, 1996
Creator: Roeder, H.; Silver, R.N.; Kress, J.D. & Landrum, G.A.
Object Type: Article
System: The UNT Digital Library
The Substance Abuse Subtle Screening Inventory: a Predictive Validity Study with Criminal Offenders Mandated to Rehabilitative Treatment (open access)

The Substance Abuse Subtle Screening Inventory: a Predictive Validity Study with Criminal Offenders Mandated to Rehabilitative Treatment

The Substance Abuse Subtle Screening Inventory was constructed to screen for substance abuse patterns despite non-admittance of respondents. Predictive validity studies of the SASSI are limited, and are not available for probationers. Participants were 147 male and 54 female probationers mandated to treatment. Overall differences among SASSI scales were significant for treatment compliance and outcome. Higher SASSI scales were found among those probationers who were compliant/successful. Individual scales were not significantly different, however, a trend was revealed; those respondents who scored higher tended to comply/succeed in treatment. The SASSI alone accurately classified 59.7% of respondents. In summary, the SASSI's use in predicting treatment outcome is limited and should be employed with concomitant data.
Date: August 1996
Creator: Flores, Johnny Martin
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Ordering of a prototypical conjugated molecular system during monolayer growth on the (1 x 2)- Au(110) surface (open access)

Ordering of a prototypical conjugated molecular system during monolayer growth on the (1 x 2)- Au(110) surface

Article on the ordering of a prototypical conjugated molecular system during monolayer growth on the (1x2)-Au(110) surface.
Date: 1996
Creator: Buongiorno Nardelli, Marco; Cvetko, D.; De Renzi, V.; Floreano, L.; Gotter, R.; Morgante, A. et al.
Object Type: Article
System: The UNT Digital Library
2l-nl{prime} x-ray transitions from neonlike charge states of the row 5 metals with 39 {le} Z {le} 46 (open access)

2l-nl{prime} x-ray transitions from neonlike charge states of the row 5 metals with 39 {le} Z {le} 46

X-ray spectra of 2l-2l{prime} transitions with 3 {le} n {le} 12 in the row five transition metals zirconium (Z = 40), niobium (Z = 41), molybdenum (Z = 42) and palladium (Z = 46) from charge states around neonlike have been observed from Alcator C-Mod plasmas. Accurate wavelengths ({+-} .2 m{angstrom}) have been determined by comparison with neighboring argon, chlorine and sulfur lines with well known wavelengths. Line identifications have been made by comparison to ab initio atomic structure calculations, using a fully relativistic, parametric potential code. For neonlike ions, calculated wavelengths and oscillator strengths are tabulated for 2p-nd transitions in Y (Z = 39), Tc (Z = 43), Ru (Z = 44) and Rh (Z = 45) with n = 6 and 7. The magnitude of the configuration interaction between the (2p{sup 5}){sub 1/2}6d{sub 3/2} J = 1 level and the (2p{sup 5}){sub 3/2}7D{sub 5/2} J = 1 levels is demonstrated as a function of atomic number for successive neonlike ions. Measured spectra of selected transitions in the aluminum-, magnesium-, sodium- and fluorine like isosequences are also shown.
Date: March 18, 1996
Creator: Rice, J. E.; Terry, J. L.; Marmar, E. S.; Fournier, K. B.; Goldstein, W. H.; Finkenthal, M. et al.
Object Type: Article
System: The UNT Digital Library
NMR Study of the Reorientational and Exchange Dynamics of Organometallic Complexes (open access)

NMR Study of the Reorientational and Exchange Dynamics of Organometallic Complexes

Investigations presented here are (a) the study of reorientational dynamics and internal rotation in transition metal complexes by NMR relaxation experiments, and (b) the study of ligand exchange dynamics in transition metal complexes by exchange NMR experiments. The phenyl ring rotation in Ru3(CO)9(μ3-CO)(μ3-NPh) and Re(Co)2(CO)10(μ3- CPh) was monitored by 13C NMR relaxation experiments to probe intramolecular electronic and/or steric interactions. It was found that the rotation is relatively free in the first complex, but is restrained in the second one. The steric interactions in the complexes were ascertained by the measurement of the closest approach intramolecular distances. The rotational energy barriers in the two complexes were also calculated by using both the Extended Hiickel and Fenske-Hall methods. The study suggests that the barrier is due mainly to the steric interactions. The exchange NMR study revealed two carbonyl exchange processes in both Ru3(CO)9(μ3-CO)(μ3-NPh) and Ru3(CO)8(PPh3)(μ3-CO)(μ3-NPh). The lower energy process is a tripodal rotation of the terminal carbonyls. The higher energy process, resulting in the exchange between the equatorial and bridging carbonyls, but not between the axial and bridging carbonyls, involves the concerted formation of edge-bridging μ2-CO moieties. The effect of the PPh3 ligand on the carbonyl exchange rates has been discussed. …
Date: May 1996
Creator: Wang, Dongqing
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Cuero Record (Cuero, Tex.), Vol. 102, No. 7, Ed. 1 Wednesday, February 14, 1996 (open access)

The Cuero Record (Cuero, Tex.), Vol. 102, No. 7, Ed. 1 Wednesday, February 14, 1996

Weekly newspaper from Cuero, Texas that includes local, state, and national news along with advertising.
Date: February 14, 1996
Creator: unknown
Object Type: Newspaper
System: The Portal to Texas History
The Ranger (San Antonio, Tex.), Vol. 71, No. 23, Ed. 1 Friday, April 19, 1996 (open access)

The Ranger (San Antonio, Tex.), Vol. 71, No. 23, Ed. 1 Friday, April 19, 1996

Weekly student newspaper from San Antonio College in San Antonio, Texas that includes campus news along with advertising.
Date: April 19, 1996
Creator: San Antonio College
Object Type: Newspaper
System: The Portal to Texas History
Treatment options for low-level radiologically contaminated ORNL filtercake (open access)

Treatment options for low-level radiologically contaminated ORNL filtercake

Water softening sludge (>4000 stored low level contaminated drums; 600 drums per year) generated by the ORNL Process Waste Treatment Plant must be treated, stabilized, and placed in safe storage/disposal. The sludge is primarily CaCO{sub 3} and is contaminated by low levels of {sup 90}Sr and {sup 137}Cs. In this study, microwave sintering and calcination were evaluated for treating the sludge. The microwave melting experiments showed promise: volume reductions were significant (3-5X), and the waste form was durable with glass additives (LiOH, fly ash). A commercial vendor using surrogate has demonstrated a melt mineralization process that yields a dense monolithic waste form with a volume reduction factor (VR) of 7.7. Calcination of the sludge at 850-900 C yielded a VR of 2.5. Compaction at 4500 psi increased the VR to 4.2, but the compressed form is not dimensionally stable. Addition of paraffin helped consolidate fines and yielded a VR of 3.5. In conclusion, microwave melting or another form of vitrification is likely to be the best method; however for immediate implementation, the calculation/compaction/waxing process is viable.
Date: April 1, 1996
Creator: Lee, Hom-Ti & Bostick, W.D.
Object Type: Report
System: The UNT Digital Library
The Llano News (Llano, Tex.), Vol. 108, No. 37, Ed. 1 Thursday, June 27, 1996 (open access)

The Llano News (Llano, Tex.), Vol. 108, No. 37, Ed. 1 Thursday, June 27, 1996

Weekly newspaper from Llano, Texas that includes local, state, and national news along with advertising.
Date: June 27, 1996
Creator: Buckner, Walter L.
Object Type: Newspaper
System: The Portal to Texas History
Messy genetic algorithms: Recent developments (open access)

Messy genetic algorithms: Recent developments

Messy genetic algorithms define a rare class of algorithms that realize the need for detecting appropriate relations among members of the search domain in optimization. This paper reviews earlier works in messy genetic algorithms and describes some recent developments. It also describes the gene expression messy GA (GEMGA)--an {Omicron}({Lambda}{sup {kappa}}({ell}{sup 2} + {kappa})) sample complexity algorithm for the class of order-{kappa} delineable problems (problems that can be solved by considering no higher than order-{kappa} relations) of size {ell} and alphabet size {Lambda}. Experimental results are presented to demonstrate the scalability of the GEMGA.
Date: September 1, 1996
Creator: Kargupta, H.
Object Type: Report
System: The UNT Digital Library
Gerhart Hauptmann: Germany throught the Eyes of the Artist (open access)

Gerhart Hauptmann: Germany throught the Eyes of the Artist

Born in 1862, Gerhart Hauptmann witnessed the creation of the German Empire, the Great War, the Weimar Republic, the Third Reich, and World War II before his death in 1946. Through his works as Germany's premier playwright, Hauptmann traces and exemplifies Germany's social, cultural, and political history during the late-nineteenth to mid-twentieth centuries, and comments on the social and political climate of each era. Hauptmann wrote more than forty plays, twenty novels, hundreds of poems, and numerous journal articles that reveal his ideas on politics and society. His ideas are reinforced in the hundreds of unpublished volumes of his diary and his copious letters preserved in the Prussian Staatsbibliothek, Berlin. In the 1960s, Germans celebrated Hauptmann's centenary as authors who had known or admired Hauptmann published biographies that chronicled his life but revealed little of his private thoughts. This dissertation examines Hauptmann's life from his early childhood through his adult life with emphasis on social and political commentaries found in his works, diaries, and letters. Hauptmann told of the social problems alcohol and greed created and used historical events to express his concern about Germany's labor and social conditions. He also used historical events to address the political problems that …
Date: December 1996
Creator: Igo, William Scott
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Simple DFT-LSDA modeling of the molecular-like aspects of ultra-thin film properties (open access)

Simple DFT-LSDA modeling of the molecular-like aspects of ultra-thin film properties

Ordered ultra-thin films (UTF`s) are atomic n-layers (n = 1,2,3,...) with translational symmetry in-plane and molecular-like inter-planar spacings. Though commonly used (especially at relatively large n-values) as models of crystalline surfaces, they are intrinsically interesting and of growing technological significance as the basic building blocks of multi-layer electronic devices. Predicting the structure and properties of even a simple diatomic 1-layer means addressing aspects of molecular binding (and boundary conditions) in the context of an extended, periodically bounded system. At the level of refinement provided by the local spin density approximation to Density Functional Theory, the baseline standard of today`s predictive, chemically specific solid-state calculations, a number of technical and fundamental issues arise. The authors focus on treatment of the isolated atoms, on basis sets, and on numerical precision, as illustrated by the Fe atom and BN 1- and 2-layer calculations. Computational requirements are illustrated by a brief summary of recently completed calculations on crystalline sapphire, {alpha}-Al{sub 2}O{sub 3}, which used the same code.
Date: September 1, 1996
Creator: Trickey, S. B.; Mathar, R. J. & Boettger, J. C.
Object Type: Article
System: The UNT Digital Library
The energetics and electronic origins for atomic long- and short-range order in Ni-Fe invar alloys (open access)

The energetics and electronic origins for atomic long- and short-range order in Ni-Fe invar alloys

States of magnetic and compositional order are strongly coupled in many magnetic alloys, with Ni-Fe Invar being the most celebrated example. Results of an electronic-based method that addresses compositional and magnetic disorder, as well as atomic short-range order and energetics, are discussed. This allows a system-dependent microscopic understanding of the interplay of chemical, magnetic, and displacive effects, and a direct comparison to diffuse scattering experiments. Discussion is in context of total-energy calculations for various magnetic states in chemically disordered and ordered Ni- Fe alloys, emphasizing the importance of exchange-splitting and the implication for phase stability in Ni-Fe system.
Date: December 31, 1996
Creator: Johnson, D. D. & Shelton, W. A.
Object Type: Article
System: The UNT Digital Library
Treatability study for removal of leachable mercury in crushed fluorescent lamps (open access)

Treatability study for removal of leachable mercury in crushed fluorescent lamps

Nonserviceable fluorescent lamps removed from radiological control areas at the Oak Ridge Department of Energy facilities have been crushed and are currently managed as mixed waste (hazardous and radiologically contaminated). We present proposed treatment flowsheets and supporting treatability study data for conditioning this solid waste residue so that it can qualify for disposal in a sanitary landfill. Mercury in spent fluorescent lamps occurs primarily as condensate on high-surface-area phosphor material. It can be solubilized with excess oxidants (e.g., hypochlorite solution) and stabilized by complexation with halide ions. Soluble mercury in dechlorinated saline solution is effectively removed by cementation with zero-valent iron in the form of steel wool. In packed column dynamic flow testing, soluble mercury was reduced to mercury metal and insoluble calomel, loading > 1.2 g of mercury per grain of steel wool before an appreciable breakthrough of soluble mercury in the effluent.
Date: February 1, 1996
Creator: Bostick, W. D.; Beck, D. E. & Bowser, K. T.
Object Type: Report
System: The UNT Digital Library