A few modeling and rendering techniques for computer graphics and their implementation on ultra hardware

Ultra network is a recently installed very high speed graphic hardware at NASA Langley Research Center. The Ultra Network interfaced to Voyager through its HSX channel is capable of transmitting up to 800 million bits of information per second. It is capable of displaying fifteen to twenty frames of precomputed images of size 1024 x 2368 with 24 bits of color information per pixel per second. Modeling and rendering techniques are being developed in computer graphics and implemented on Ultra hardware. A ray tracer is being developed for use at the Flight Software and Graphic branch. Changes were made to make the ray tracer compatible with Voyager

Treatment or Unconformity Zone and Curtain Grouting in Foundation of Almatti Dam on Krishna River

Curtain Grouting is an important component of Foundation treatment of Dam and other hydraulic structures. The purpose of Curtain Grouting is to form a zone of low permeability upto a designed depth on the upstream of the dam. This grout curtain along with downstream drainage system controls the uplift pressure and piping which are potential hazards. The present case study deals with providing grout curtain to Almatti Masonry Dam from Block No. 1 to 52. Besides curtain grouting this case study also deals with the treatment of weak zone (unconformity zone) of thickness upto 6 m, which was existing in the foundation from Block No. 45 to 52 below the joint of base granite rock and overlying quartzite foundation. The single line grout curtain of permeability less than 3 Lugeon has been effectively formed below the foundation, despite very poor strata having maximum pre-grout permeability of 90 Lugeon

Improvements to the Langley HZE abrasion model

Improvements to a previously developed high charge energy abrasion model are made by incorporating more realistic values for the constituent Fermi momentum and nucleon root-mean-square charge radius. The theoretical predictions for neon projectiles at 2.1 GeV/nucleon colliding with carbon and molybdenum targets are in excellent agreement with recent experiment results

Grouting Technology for Rehabilitation of Tillar Earthen Dam

Over the last few decades grouting technology has grown into one of the disciplines in geotechnical engineering comprising mainly of foundation treatment of dams and other structures by strengthening or by making them impermeable and has become one of the main tool to rehabilitate the dams structurally. The present case study deals with structural rehabilitation of Tillar earthen dam which was constructed in 1987 but distress signals had started from the first impounding. Highly permeable strata having permeability to the tune of 0.36 x 10-1 cm/sec was existing between the bottom of Cut off Trench (COT) and foundation rock. From this zone water was permeating and causing danger to the stability of the dam. Grout curtain in the permeable zone, below COT bed and upto foundation rock by using the special technique namely Tube-a-Manchatte Grouting was used to reduce the permeability from 10-1 cm/sec to 10-5 cm/sec and also to provide grout curtain in foundation rock upto 7 m depth

Phenomenological optical potential analysis of proton-carbon elastic scattering at 200 MeV

Differential cross sections for 200 MeV protons elastically scattered from C-12 were analyzed utilizing a local, complex, spin-dependent optical potential with a harmonic well radial dependence. Analyses were performed using the WKB and eikonal approximations. For the latter, first-order corrections to he phase shifts were incorporated to account for the spin-orbit contribution. Large disagreement between theory and experiment was observed when the usual Thomas form for the spin-orbit potential was utilized. Substantial improvement was obtained by allowing the parameters in the central and spin-orbit potential terms to vary independently

Electronic and mechanical properties of chemically functionalized nanowires

Organic and inorganic nanostructured materials, nano- and mesoscale objects and devices, and their integration into existing microelectronic technologies have been at the center of recent fundamental and applied research in nanotechnology. One of the critical needs is to develop an enhanced predictive capability of structure-property correlations and enable robust high performance systems by design. My thesis work was concerned with the theoretical and experimental studies of electronic and mechanical properties of chemically functionalized nanowires. I will describe a theoretical approach for investigating structure-property correlations in atomic-sized metallic wires based on the Density Functional Theory (DFT) for structure calculations and the Non-equilibrium Green's Function (NEGF) technique for electronic transport properties simulations. This synergistic approach is shown to yield the atomic structure of the smallest niobium nanowires. Furthermore, the method was applied to simulate electronic properties of chemically functionalized graphene nanoribbons. Further, I will demonstrate an experimental technique for simultaneous measurements of force and conductance in atomic-size objects based on quartz tuning fork piezoelectric sensors. A peculiar scaling effect, relevant for a broad range of test and measurement applications, namely the squeeze film effect, was observed during the development of the sensors. Using theoretical analysis based on finite element simulations of the hydrodynamic behavior of the sensors in a broad range of ambient conditions, I explain the observed phenomenon.Ph.D.Committee Chair: Marchenkov, Alexei; Committee Member: Callen, William Russell; Committee Member: First, Phillip; Committee Member: Kindermann, Marcus; Committee Member: Riedo, Elis

Heavy-ion total and absorption cross sections above 25 MeV/nucleon

Within the context of a double-folding optical potential approximation to the exact nucleus-nucleus multiple-scattering series, eikonal scattering theory is used to generate tables of heavy ion total and absorption cross sections at incident kinetic energies above 25 MeV/nucleon for use in cosmic ray high-energy heavy ion transport and shielding studies. Comparisons of predictions with nucleus-nucleus experimental data show excellent agreement except at the lowest energies, where the eikonal approximation may not be completely valid. Even at the lowest energies, however, agreement is typically within 20 percent

Anchored RCC Diaphragm Wall Coffer Dam for Bisalpur Dam (A Case - Study)

Construction of dam foundation of Bisalpur masonry dam on river Banas was posing a problem due to presence of medium and coarse sand in the river bed. In post monsoon period, though there remains very little surface flow in the river, but ipso-facto entire river flows through 10 to 12 m thick sand bed. Hence RCC diaphragm wall was conceived to play dual role i.e. to cut off the flow through the sand bed and also to act as coffer dam to divert the surface flow in the diversion channel. 60 cm thick RCC diaphragm wall has been constructed and used as cut off as well as coffer dams on u/s and d/s side of main dam. Wherever depth of diaphragm wall was less than 12 m, post tension anchors of capacity 135 Tons to 170 Tons at an inclination of 45 degrees, were provided through the diaphragm wall and sand bed and grouted in rock. Wherever depth of diaphragm wall was more than 12 m, it was designed as T shaped wall on principle of counter fort retaining wall. This coffer dam cum cut off wall had served its purpose and facilitated the construction of foundation and main dam of Bisalpur project

Neon transport in selected organic composites

An energy-dependent, perturbation expansion solution for heavy-ion transport in one dimension was used to calculate the dose from Ne-20 beams at incident kinetic energies of 350, 670, and 2000 MeV/amu onto selected organic composites. Transport coefficients, applicable to arbitrary ion beams over a broad range of energies, are presented. Polyethylene and Kapton were tested as constituents of multilayered shielding for spacecraft and astronauts

Nucleon and deuteron scattering cross sections from 25 MV/Nucleon to 22.5 GeV/Nucleon

Within the context of a double-folding optical potential approximation to the exact nucleus-nucleus multiple-scattering series, eikonal scattering theory is used to generate tables of nucleon and deuteron total and absorption cross sections at kinetic energies between 25 MeV/nucleon and 22.5 GeV/nucleon for use in cosmic-ray transport and shielding studies. Comparisons of predictions for nucleon-nucleus and deuteron-nucleus absorption and total cross sections with experimental data are also made