Best approaches to teach students with learning disabilities at the college level

My capstone project is very unique and focuses on a topic that I am very passionate about and that is students with Learning Disabilities in higher education and how to best accommodate them while college. I also wrote a professional piece which is an autobiography about my life. But the book also is guide that through research is designed to help students. Taking all the resources and programs I was in and passing the word on so others can have access to the programs that helped me succeed. I happen to be student with learning disabilities and have had to overcome a lot in my life to get to where I am at today

Recombination models for defects in silicon solar cells

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Generality of liquid precursor phases in gas diffusion-based calcium carbonate synthesis

The ammonia diffusion method (ADM) is one of the most widely used strategies for the bioinspired synthesis of minerals. Herein, we present investigations of the mineralization mechanism using an advanced ADM to solve the limitations of the conventional ADM. This allows us to confirm the presence of liquid calcium carbonate precursor species in additive-free and polymer-stabilized gas diffusion systems, indicating that liquid-liquid phase separated species exhibit sufficient kinetic stability to be detected. Time-dependent experiments reveal the role of these precursor phases during the early stages of the crystallization process, demonstrating that liquid calcium carbonate mineral precursors play an important role in the precipitation pathway and must be generally considered for the interpretation of gas diffusion experiments, with and without additives. This discovery poses an important step in the understanding of how minerals are formed, highlighting that nonclassical mineralization processes must be considered for material synthesis. Last but not least, the advanced ADM may be useful for the exploration of the formation mechanism of other minerals than calcium carbonate, which are also of broad interest in the materials chemistry community

High-order harmonic generation with ultra-short pulses from filamentation

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A Combined Statistical and TCAD Model as a Method for Understanding and Reducing Variations in Multicrystalline Si Solar Cell Production

AbstractMonitoring the I-V parameters in mass production yields a distribution that cannot be understood in a simple manner. For example, if Voc varies greatly, it is not obvious whether this is mainly due to variations in the bulk lifetime or in the surface passivation or due to other sources.In this work, we develop a method where statistics is combined with numerical device modeling to obtain a physical interpretation of the observed variations. In the first part, we derive a multivariate statistical model to extract the main influences of fabrication fluctuations on the I-V parameters. This statistical model is based on cell parameters measured on a representative sample of solar cells from production. In the second part, we develop a computer-aided design (TCAD) device simulation model for multicrystalline Si solar cells. This TCAD model quantifies the I-V variations on a physically sound basis. However, the number of simulations is grossly reduced by feeding in solely the main influences obtained from the statistical model. In the third part, we verify this method by comparing the calculated distribution with production data.This model is used for optimization strategies for higher cell efficiency, smaller variations in cell parameters and improved yield in mass production. Furthermore, we will apply our methodology to advanced cell concepts. It will allow the early consideration of production fluctuation in device simulation of advanced cell concepts, and therefore a realistic assessment of such concepts

High-order-harmonic generation from dense water microdroplets

We report on high-order-harmonic generation from micrometer-sized liquid water droplets. In pump-probe experiments, the influence of the time delay onto the emission of harmonic radiation is systematically studied. Phase-matching aspects are observed by controlling the focal position and the intensity of the probe pulse. The spatiotemporal dynamics of the droplet during interaction with intense laser pulses are studied by controlling the intensity of the pump pulse. We find transient phase-matching conditions and the expansion dynamics of the droplet to be of major influence on the harmonic yield. © 2013 American Physical Society.DFG/EXC/QUESTDFG/KO 3798/1-

Spatial contributions of electron trajectories to high-order-harmonic radiation originating from a semi-infinite gas cell

We report on the analysis of the spatial beam profile of high-order harmonic radiation originating from a semi-infinite gas cell (SIGC). We experimentally assign contributions of electron trajectories to different spatial regions of the harmonic radiation beam. The angular divergence of the harmonic radiation is studied for the first time in a SIGC as a function of different phase-matching parameters. We relate the ratio of the dipole phase coefficients to the coherence time and divergence angle measurements. Simulations, including high-order-harmonic propagation, give further insight into the generation process and the influence of phase matching. The analysis reveals that the SIGC enables tuning of the cutoff frequency by altering the absorption of the generating medium.The authors thank Vasily V. Strelkov and Pascal Salie`res for valuable discussions and the Deutsche Forschungsge- meinschaft DFG and the Cluster of Excellence QUEST for financial support of this work. Carlos Hernández-García and Luis Plaja acknowledge support from Junta de Castilla y León (Consejería de Educación and Fondo Social Europeo) and Spanish MINECO (FIS2009-09522)

Solar cell emitter design with PV-tailored implantation

A potentially cost-effective ion implanter for solar cells has become commercially available very recently. As the emitter dopant profiles differ from the standard diffusions, a combination of process simulation and device simulation is used to predict possible applications as front emitter. The simulations show that ion energies of 10 to 30 keV and doses in the range of 5×1014 to 7×1015 cm-2 are sufficient for reducing the phosphorus peak density and, hence, obtaining cell efficiency levels above 20%, if appropriate surface passivation and wafer materials are used. The simulations strongly indicate, however, that cell efficiency improves only marginally if the cell has a fully metallized rear Al-BSF and a boron-doped Cz base in the degraded state. Simulated cells with a local rear Al-BSF show an efficiency improvement of more than 0.3% absolute in the degraded state

High-order harmonic generation directly from a filament

The synthesis of isolated attosecond pulses (IAPs) in the extreme ultraviolet (XUV) spectral region has opened up the shortest time scales for timeresolved studies. It relies on the generation of high-order harmonics (HHG) from high-power few-cycle infrared (IR) laser pulses. Here we explore experimentally a new and simple route to IAP generation directly from 35 fs IR pulses that undergo filamentation in argon. Spectral broadening, self-shortening of the IR pulse and HHG are realized in a single stage, reducing the cost and experimental effort for easier spreading of attosecond sources. We observe continuous XUV spectra supporting IAPs, emerging directly from the filament via a truncating pinhole to vacuum. The extremely short absorption length of the XUV radiation makes it a highly local probe for studying the elusive filamentation dynamics and in particular provides an experimental diagnostic of short-lived spikes in laser intensity. The excellent agreement with numerical simulations suggests the formation of a single-cycle pulse in the filament. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft

Tracking spectral shapes and temporal dynamics along a femtosecond filament

The spectral evolution of a high-intensity light channel formed by filamentation is investigated in a detailed experimental study. We also track the spatio-temporal dynamics by high-order harmonic generation along the filament. Both the spectral and temporal diagnostics are performed as a function of propagation distance, by extracting the light pulses directly from the hot filament core into vacuum via pinholes that terminate the nonlinear propagation. We compare the measured spectral shapes to simulations and analyze numerically the temporal dynamics inside the filament. © 2011 Optical Society of America