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In-Line Crack and Stress Detection in Silicon Solar Cells Using Resonance Ultrasonic Vibrations

Description: Statement of Problem and Objectives. Wafer breakage in automated solar cell production lines is identified as a major technical problem and a barrier for further cost reduction of silicon solar module manufacturing. To the best of our knowledge, there are no commercial systems addressing critical needs for in-line inspection of the mechanical quality of solar wafers and cells. The principal objective of the SBIR program is to validate through experiments and computer modeling the applicability of the Resonance Ultrasonic Vibrations system, which ultimately can be used as a real-time in-line manufacturing quality control tool for fast detection of mechanically unstable silicon solar cells caused by cracks. The specific objective of Phase II is to move the technology of in-line crack detection from the laboratory level to commercial demonstration through development of a system prototype. The fragility of silicon wafers possessing low mechanical strength is attributed to peripheral and bulk millimeter-length cracks. The research program is based on feasibility results obtained during Phase I, which established that: (i) the Resonance Ultrasonic Vibrations method is applicable to as-cut, processed wafers and finished cells; (ii) the method sensitivity depends on the specific processing step; it is highest in as-cut wafers and lowest in wafers with metallization pattern and grid contacts; (iii) the system is capable of matching the 2.0 seconds per wafer throughput rate of state-of-art solar cell production lines; (iv) finite element modeling provides vibration mode analysis along with peak shift versus crack length and crack location dependence; (v) a high 91% crack rejection rate was confirmed through experimentation and statistical analysis. The Phase II project has the following specific tasks: (i) specify optimal configurations of the in-line system’s component hardware and software; (ii) develop and justify a system prototype that meets major specifications for an in-line crack detection unit, such as ...
Date: April 3, 2013
Creator: Ostapenko, Sergei
Partner: UNT Libraries Government Documents Department

Instability, Collapse and Oscillation of Sheaths Caused by Secondary Electron Emission

Description: The Debye sheath is shown to be unstable under general conditions. For surface materials with sufficient secondary electron emission (SEE) yields, the surface's current-voltage characteristic has an unstable branch when the bulk plasma temperature (Te ) exceeds a critical value, or when there are fast electron populations present. The plasma-surface interaction becomes dynamic where the sheath may undergo spontaneous transitions or oscillations. Using particle-in-cell simulations, we analyze sheath instabilities occurring in a high Te plasma slab bounded by walls with SEE. As the plasma evolves, whenever the sheath enters an unstable state, its amplitude rapidly collapses, allowing a large flux of previously trapped electrons to hit the wall. These hot electrons induce more than one secondary on average, causing a net loss of electrons from the wall. The sheath collapse quenches when the surface charge becomes positive because the attractive field inhibits further electrons from escaping. Sheath instabilities influence the current balance, energy loss, cross-B-field transport and even the bulk plasma properties. Implications for discharges including Hall thrusters are discussed. More generally, the results show that common theories that treat emission as a fixed (time-independent) "coefficient" do not capture the full extent of SEE effects.
Date: January 3, 2013
Creator: M.D. Campanell, A.V. Khrabrov and I.D. Kaganovich
Partner: UNT Libraries Government Documents Department

Superhydrophobic Materials Technology-PVC Bonding Techniques

Description: The purpose of the technology maturation project was to develop an enhanced application technique for applying diatomaceous earth with pinned polysiloxane oil to PVC pipes and materials. The oil infiltration technique is applied as a spray of diluted oil in a solvent onto the superhydrophobic diatomaceous earth substrate. This makes the surface take on the following characteristics: • wet‐cleanable • anti‐biofouling • waterproof • anti‐corrosion. The project involved obtaining input and supplies from VeloxFlow and the development of successful techniques that would quickly result in a commercial license agreement with VeloxFlow and other companies that use PVC materials in a variety of other fields of use.
Date: May 3, 2013
Creator: Hunter, Scott R. & Efird, Marty
Partner: UNT Libraries Government Documents Department

Control of Suspect/Counterfeit and Defective Items

Description: This procedure implements portions of the requirements of MSC-MP-599, Quality Assurance Program Description. It establishes the Mission Support Alliance (MSA) practices for minimizing the introduction of and identifying, documenting, dispositioning, reporting, controlling, and disposing of suspect/counterfeit and defective items (S/CIs). employees whose work scope relates to Safety Systems (i.e., Safety Class [SC] or Safety Significant [SS] items), non-safety systems and other applications (i.e., General Service [GS]) where engineering has determined that their use could result in a potential safety hazard. MSA implements an effective Quality Assurance (QA) Program providing a comprehensive network of controls and verification providing defense-in-depth by preventing the introduction of S/CIs through the design, procurement, construction, operation, maintenance, and modification of processes. This procedure focuses on those safety systems, and other systems, including critical load paths of lifting equipment, where the introduction of S/CIs would have the greatest potential for creating unsafe conditions.
Date: September 3, 2013
Creator: Sheriff, Marnelle L.
Partner: UNT Libraries Government Documents Department

Ecological Monitoring and Compliance Program 2012 Report

Description: The Ecological Monitoring and Compliance Program (EMAC), funded through the U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office (NNSA/NFO, formerly Nevada Site Office), monitors the ecosystem of the Nevada National Security Site (NNSS) and ensures compliance with laws and regulations pertaining to NNSS biota. This report summarizes the program’s activities conducted by National Security Technologies, LLC (NSTec), during calendar year 2012. Program activities included (a) biological surveys at proposed construction sites, (b) desert tortoise compliance, (c) ecosystem monitoring, (d) sensitive plant species monitoring, (e) sensitive and protected/regulated animal monitoring, (f) habitat restoration monitoring, and (g) monitoring of the Nonproliferation Test and Evaluation Complex (NPTEC). During 2012, all applicable laws, regulations, and permit requirements were met, enabling EMAC to achieve its intended goals and objectives.
Date: July 3, 2013
Creator: Hall, Derek B.; Anderson, David C.; Greger, Paul D.; Ostler, W. Kent & Hansen, Dennis J.
Partner: UNT Libraries Government Documents Department


Description: The 2012 Gordon Conference on Electrodeposition: Electrochemical Materials Synthesis and Applications will present cutting-edge research on electrodeposition with emphasis on (i) advances in basic science, (ii) developments in next-generation technologies, and (iii) new and emerging areas. The Conference will feature a wide range of topics, from atomic scale processes, nucleation and growth, thin film deposition, and electrocrystallization, to applications of electrodeposition in devices including microelectronics, batteries, solar energy, and fuel cells.
Date: August 3, 2013
Creator: Gewirth, Andrew
Partner: UNT Libraries Government Documents Department

Final Report - LAW Envelope A and B Glass Formulations Testing in Increase Waste Loading. VSL-06R6900-1

Description: This report describes the results of testing specified by the Test Plan VSL-06R6900-1 Rev 0. The work was performed in compliance with quality assurance requirements specified in the Test Plan. Results required by the Test Plan are reported. The test results and this report have been reviewed for correctness, technical adequacy, completeness, and accuracy.
Date: December 3, 2013
Creator: Kruger, Albert A.; Joseph, I.; Muller, I. S.; Gong, W.; Gan, H.; Pegg, I. L. et al.
Partner: UNT Libraries Government Documents Department

Final Report - LAW Envelope C Glass Formulation Testing to Increase Waste Loading, VSL-05R5900-1

Description: This report describes the results of testing specified by Test Plan VSL-05R5900-1 Rev.0. The work was performed in compliance with the quality assurance requirements specified in the Test Plan. Results required by the Test Plan are reported. The test results and this report have been reviewed for correctness, technical adequacy, completeness, and accuracy.
Date: December 3, 2013
Creator: Kruger, Albert A.; Pegg, I. L.; Matlack, K. S.; Joseph, I.; Muller, I. S. & Gong, W.
Partner: UNT Libraries Government Documents Department