Direct-Write Contacts for Solar Cells (open access)

Direct-Write Contacts for Solar Cells

We report on our project to develop inkjet printable contacts for solar cells. Ag, Cu, and Ni metallizations were inkjet printed with near vacuum deposition quality. Thick, highly conducting lines of Ag and Cu demonstrating good adhesion to glass, Si, and PCB have been printed at 100-200 C in air and N2, respectively. Ag grids were inkjet-printed on Si solar cells and fired through silicon nitride AR layer at 850 C resulting in 8% cells. Next-generation multicomponent inks (including etching agents) have also been developed with improved fire-through contacts leading to higher cell efficiencies. The approach developed can be easily extended to other conductors such as Pt, Pd, and Au, etc. In addition, PEDOT-PSS polymer-based conductors were inkjet-printed with the conductivity as good or better than those of polymer-based conductors.
Date: January 1, 2005
Creator: Kaydanova, T.; van Hest, M. F. A. M.; Miedaner, A.; Curtis, C. J.; Alleman, J. L.; Dabney, M. S. et al.
Object Type: Article
System: The UNT Digital Library
Proposed Route to Thin Film Crystal Si Using Biaxially Textured Foreign Template Layers (open access)

Proposed Route to Thin Film Crystal Si Using Biaxially Textured Foreign Template Layers

We have developed a new approach to growing photovoltaic-quality crystal silicon (c-Si) films on glass. Other approaches to film c-Si focus on increasing grain size in order to reduce the deleterious effects of grain boundaries. Instead, we have developed an approach to align the silicon grains biaxially (both in and out of plane) so that 1) grain boundaries are "low-angle" and have less effect on the electronic properties of the material and 2) subsequent epitaxial thickening is simplified. They key to our approach is the use of a foreign template layer that can be grown with biaxial texture directly on glass.
Date: November 1, 2005
Creator: Teplin, C. W.; Ginley, D. S.; van Hest, M. F. A. M.; Perkins, J. D.; Young, D. L.; Stradins, P. et al.
Object Type: Article
System: The UNT Digital Library
Metabolic Engineering to Develop a Pathway for the Selective Cleavage of Carbon-Nitrogen Bonds (open access)

Metabolic Engineering to Develop a Pathway for the Selective Cleavage of Carbon-Nitrogen Bonds

The objective of the project is to develop a biochemical pathway for the selective cleavage of C-N bonds in molecules found in petroleum. Specifically a novel biochemical pathway will be developed for the selective cleavage of C-N bonds in carbazole. The cleavage of the first C-N bond in carbazole is accomplished by the enzyme carbazole dioxygenase, that catalyzes the conversion of carbazole to 2-aminobiphenyl-2,3-diol. The genes encoding carbazole dioxygenase were cloned from Sphingomonas sp. GTIN11 and from Pseudomonas resinovorans CA10. The selective cleavage of the second C-N bond has been challenging, and efforts to overcome that challenge have been the focus of recent research in this project. Enrichment culture experiments succeeded in isolating bacterial cultures that can metabolize 2-aminobiphenyl, but no enzyme capable of selectively cleaving the C-N bond in 2-aminobiphenyl has been identified. Aniline is very similar to the structure of 2-aminobiphenyl and aniline dioxygenase catalyzes the conversion of aniline to catechol and ammonia. For the remainder of the project the emphasis of research will be to simultaneously express the genes for carbazole dioxygenase and for aniline dioxygenase in the same bacterial host and then to select for derivative cultures capable of using carbazole as the sole source of …
Date: October 1, 2005
Creator: Kilbane, John J., II
Object Type: Report
System: The UNT Digital Library
Computational Modeling of Uranium Corrosion and the role of Impurities(Fe, Cr, Al, C and Si) (open access)

Computational Modeling of Uranium Corrosion and the role of Impurities(Fe, Cr, Al, C and Si)

My talk will focus on our recent computational modeling results of uranium corrosion and the impact of impurities on uranium corrosion, which occurs primarily through hydriding Uranium hydriding is one of the most important processes that has received considerable attention over many years. Although significant number of experimental and modeling studies have been carried out concerning thermo chemistry, diffusion kinetics and mechanisms of U-hydriding, very little is known about the electronic structure and electronic features that govern the U-hydriding process. Our modeling efforts focus the electronic feature that controls the activation barrier and thus the rate of hydriding. Our recent efforts have been focused on the role of impurities such as Fe, Cr, Si, C, Al and so on. Moreover the role of impurities and the role of the product UH{sub 3} on hydriding rating have not been fully understood. Condon's diffusion model was found to be in excellent agreement with the experimental reaction rates. From the slopes of the Arrhenius plot the activation energy was calculated as 6.35 kcal/mole. Bloch and Mintz have discussed two models, one, which considers hydrogen diffusion through a protective UH{sub 3} product layer, and the second where hydride growth occurs at the hydride-metal interface. …
Date: October 31, 2005
Creator: Balasubramanian, K.; Sikehaus, W.; Balazs, B. & McLean, W., II
Object Type: Article
System: The UNT Digital Library
Kinetic measurement and prediction of the hydrogen outgassing from the polycrystalline LiH/Li2O/LiOH system (open access)

Kinetic measurement and prediction of the hydrogen outgassing from the polycrystalline LiH/Li2O/LiOH system

Due to the exothermic reaction of lithium hydride (LiH) salt with water during transportation and handling, there is always a thin film of lithium hydroxide (LiOH) present on the LiH surface. In dry or vacuum storage, this thin LiOH film slowly decomposes. We have used temperature-programmed reaction/decomposition (TPR) in combination with the isoconversion method of thermal analysis to determine the outgassing kinetics of H{sub 2}O from pure LiOH and H{sub 2} and H{sub 2}O from this thin LiOH film. H{sub 2} production via the reaction of LiH with LiOH, forming a lithium oxide (Li{sub 2}O) interlayer, is thermodynamically favored, with the rate of further reaction limited by diffusion through the Li{sub 2}O and the stability of the decomposing LiOH. Lithium hydroxide at the LiOH/vacuum interface also decomposes easily to Li{sub 2}O, releasing H{sub 2}O which subsequently reacts with LiH in a closed system to form H{sub 2}. At the onset of dry decomposition, where H{sub 2} is the predominant product, the activation energy for outgassing from a thin LiOH film is lower than that for bulk LiOH. However, as the reactions at the LiH/Li{sub 2}O/LiOH and at the LiOH/vacuum interfaces proceed, the overall activation energy barrier for the outgassing approaches …
Date: April 6, 2005
Creator: Dinh, L. N.; Grant, D. M.; Schildbach, M. A.; Smith, R. A.; Siekhaus, W. J.; Balazs, B. et al.
Object Type: Article
System: The UNT Digital Library
Kinetic measurement and prediction of the hydrogen outgassing from the polycrystalline LiH/LiOH system (open access)

Kinetic measurement and prediction of the hydrogen outgassing from the polycrystalline LiH/LiOH system

In this report, we present the use of temperature programmed reaction/decomposition (TPR) in the isoconversion mode to measure outgassing kinetics and to make kinetic prediction concerning hydrogen release from the polycrystalline LiH/LiOH system in the absence of any external H{sub 2}O source.
Date: March 9, 2005
Creator: Dinh, L. N.; Grant, D. M.; Schildbach, M. A.; Smith, R. A.; Leckey, J. H.; Siekhaus, W. J. et al.
Object Type: Article
System: The UNT Digital Library
Shape Memory Polymer Therapeutic Devices for Stroke (open access)

Shape Memory Polymer Therapeutic Devices for Stroke

Shape memory polymers (SMPs) are attracting a great deal of interest in the scientific community for their use in applications ranging from light weight structures in space to micro-actuators in MEMS devices. These relatively new materials can be formed into a primary shape, reformed into a stable secondary shape, and then controllably actuated to recover their primary shape. The first part of this presentation will be a brief review of the types of polymeric structures which give rise to shape memory behavior in the context of new shape memory polymers with highly regular network structures recently developed at LLNL for biomedical devices. These new urethane SMPs have improved optical and physical properties relative to commercial SMPs, including improved clarity, high actuation force, and sharper actuation transition. In the second part of the presentation we discuss the development of SMP based devices for mechanically removing neurovascular occlusions which result in ischemic stroke. These devices are delivered to the site of the occlusion in compressed form, are pushed through the occlusion, actuated (usually optically) to take on an expanded conformation, and then used to dislodge and grip the thrombus while it is withdrawn through the catheter.
Date: October 11, 2005
Creator: Wilson, T. S.; Small, W., IV; Benett, W. J.; Bearinger, J. P. & Maitland, D. J.
Object Type: Article
System: The UNT Digital Library
X-Ray Imaging Of Cryogenic Deuterium-Tritium Layers In A Beryllium Shell (open access)

X-Ray Imaging Of Cryogenic Deuterium-Tritium Layers In A Beryllium Shell

None
Date: June 1, 2005
Creator: Kozioziemski, B. J.; Sater, J. D.; Moody, J. D.; Sanchez, J. J.; London, R. A.; Barty, A. et al.
Object Type: Article
System: The UNT Digital Library
Piecewise linear discretization of Symbolic Implicit Monte Carlo radiation transport in the difference formulation (open access)

Piecewise linear discretization of Symbolic Implicit Monte Carlo radiation transport in the difference formulation

We describe a Monte Carlo solution for time dependent photon transport, in the difference formulation with the material in local thermodynamic equilibrium (LTE), that is piecewise linear in its treatment of the material state variable. Our method employs a Galerkin solution for the material energy equation while using Symbolic Implicit Monte Carlo (SIMC) to solve the transport equation. In constructing the scheme, one has the freedom to choose between expanding the material temperature, or the equivalent black body radiation energy density at the material temperature, in terms of finite element basis functions. The former provides a linear treatment of the material energy while the latter provides a linear treatment of the radiative coupling between zones. Subject to the conditional use of a lumped material energy in the vicinity of strong gradients, possible with a linear treatment of the material energy, our approach provides a robust solution for time dependent transport of thermally emitted radiation that can address a wide range of problems. It produces accurate results in the diffusion limit.
Date: November 15, 2005
Creator: Brooks, E. D., III; Szoke, A. & Peterson, J. D. L.
Object Type: Article
System: The UNT Digital Library
Influence of Pressure-gradient and Shear on Ballooning Stability in Stellarators (open access)

Influence of Pressure-gradient and Shear on Ballooning Stability in Stellarators

Pressure-driven, ideal ballooning stability calculations are often used to predict the achievable plasma in stellarator configurations. In this paper, the sensitivity of ballooning stability to plasmas profile variations is addressed. A simple, semi-analytic method for expressing the ballooning growth rate, for each field line, as a polynomial function of the variation in the pressure gradient and the average magnetic shear from an original equilibrium has recently been introduced [Phys. Plasmas 11:9 (September 2004) L53]. This paper will apply the expression to various stellarator configurations and comment on the validity of various truncated forms of the polynomial expression. In particular, it is shown that in general it is insufficient to consider only the second order terms as previously assumed, and that higher order terms must be included to obtain accurate predictions of stability.
Date: February 28, 2005
Creator: Hudson, S. R.; Hegna, C. C. & Nakajima, N.
Object Type: Report
System: The UNT Digital Library
Development and Manufacture of Cost Effective Composite Drill Pipe (open access)

Development and Manufacture of Cost Effective Composite Drill Pipe

This technical report presents the engineering research, process development and data accomplishments that have transpired to date in support of the development of Cost Effective Composite Drill Pipe (CDP). The report presents progress made from October 1, 2003 through September 30, 2004 and contains the following discussions: (1) Direct Electrical Connection for Rotary Shoulder Tool Joints; (2) Conductors for inclusion in the pipe wall (ER/DW-CDP); (3) Qualify fibers from Zoltek; (4) Qualify resin from Bakelite; (5) First commercial order for SR-CDP from Integrated Directional Resources (SR-CDP); and (6) Preparation of papers for publication and conference presentations.
Date: March 18, 2005
Creator: Leslie, James C.; Leslie, James C., II; Truong, Lee; Heard, James T. & Manekas, Peter
Object Type: Report
System: The UNT Digital Library
Subtask 7.2 Global Warming and Greehouse Gases (open access)

Subtask 7.2 Global Warming and Greehouse Gases

Evaluation of current climatic trends and reconstruction of paleoclimatic conditions for Devils Lake have been conducted based on diatom-inferred salinity for the last 2000 years. The 3-year cross-disciplinary research, funded by the U.S. Department of Energy (DOE) was carried out by the Energy & Environmental Research Center (EERC) and St. Croix Watershed Research Station (SCWRS) at the Science Museum of Minnesota. The results indicate that frequent climatic fluctuations resulting in alternating periods of drought and wet conditions are typical for the northern Great Plains and suggest that the severity and length of extremes exceeded those on modern record. Devils Lake has experienced five fresh periods and two minor freshening periods in the last 2000 years. Transitions between fresh and saline periods have been relatively fast, representing lake level changes that have been similar to those observed in the last 150 years. From 0 to 1070 A.D., Devils Lake showed more variable behavior, with fresh phases centered at 200, 500, 700, and 1000 A.D. From 1070 A.D. to present, Devils Lake was generally saline, experiencing two minor freshening periods at 1305-1315 and 1800-1820 A.D and the major current freshening from 1960 A.D. to present.
Date: January 1, 2005
Creator: Solc, Jaroslav; Eylands, Kurt; Solc, Jaroslav, Jr.; Mueller, Sara; Engstrom, Daniel & Edlund, Mark
Object Type: Report
System: The UNT Digital Library
Reformulation of Coal-Derived Transportation Fuels: Selective Oxidation of Carbon Monoxide on Metal Foam Catalysts (open access)

Reformulation of Coal-Derived Transportation Fuels: Selective Oxidation of Carbon Monoxide on Metal Foam Catalysts

Hydrocarbon fuels must be reformed in a series of steps to provide hydrogen for use in proton exchange membrane fuel cells (PEMFCs). Preferential oxidation (PROX) is one method to reduce the CO concentration to less than 10 ppm in the presence of {approx}40% H{sub 2}, CO{sub 2}, and steam. This will prevent CO poisoning of the PEMFC anode. Structured supports, such as ceramic monoliths, can be used for the PROX reaction. Alternatively, metal foams offer a number of advantages over the traditional ceramic monolith.
Date: June 1, 2005
Creator: Chin, Paul; Sun, Xiaolei; Roberts, George W.; Sirijarhuphan, Amornmart; Pansare, Sourabh; Goodwin, James G., Jr. et al.
Object Type: Report
System: The UNT Digital Library
The Journey to Fielded BioInstrumentation (open access)

The Journey to Fielded BioInstrumentation

Over the last ten years, a team at Lawrence Livermore National Laboratory created fieldable instruments that performed identification/quantification via bioassays. These instruments have been based on molecular surface-recognition assays, such as immunoassays, and on nucleic-acid-based assays, such as the polymerase chain reaction. In 1996, we participated in the Joint Field Trials 3, employing both immunoassays as well as the polymerase chair reaction. In 1998, we participated in the Joint Field Trials 4, using only the real-time polymerase chain reaction, as implemented on a 10-chamber instrument. Our hand-held, real-time PCR instrument, known as HANAA has been commercialized as the Bioseeq{reg_sign}, by Smiths Detection. More recently, teams from LLNL have built and fielded an autonomous pathogen detection system (APDS).
Date: February 24, 2005
Creator: Mariella, R., Jr.
Object Type: Article
System: The UNT Digital Library