Photoelectrochemical fabrication of spectroscopic diffraction gratings

Photoelectrochemical etching was demonstrated as a means of fabricating a variety of periodic structures in semiconductors. The semiconductor is used as an electrode in an electrochemical cell, and is in contact with a liquid electrolyte. When the crystal is held at a positive voltage and illuminated, etching occurs in only the illuminated regions to a depth proportional to the illumination intensity and exposure time. In Phase 1, it was determined that diffraction gratings could be produced in gallium arsenide crystals by this method, using either a scanned focused laser beam or by uniform illumination of a ruling mask defined in metal or photoresist on the crystal surface. The latter approach was determined to produce V-grooves if the mask is oriented along certain crystallographic directions. These V-grooves were produced with an exceedingly smooth crystal morphology due to the highly controllable nature of the process and the mild electrolytes involved. The results form the basis for photoelectrochemical fabrication of deep, low pitch Eschelle gratings for use in high orders in NASA spectrographic instrumentation such as the Space Telescope Imaging Spectrograph

Hydrogen production by photoelectrolytic decomposition of H2O using solar energy

Photoelectrochemical systems for the efficient decomposition of water are discussed. Semiconducting d band oxides which would yield the combination of stability, low electron affinity, and moderate band gap essential for an efficient photoanode are sought. The materials PdO and Fe-xRhxO3 appear most likely. Oxygen evolution yields may also be improved by mediation of high energy oxidizing agents, such as CO3(-). Examination of several p type semiconductors as photocathodes revealed remarkable stability for p-GaAs, and also indicated p-CdTe as a stable H2 photoelectrode. Several potentially economical schemes for photoelectrochemical decomposition of water were examined, including photoelectrochemical diodes and two stage, four photon processes

How do transfers and universal basic income impact the labor market and inequality?

This paper studies the impact of existing and universal transfer programs on vacancy creation, wages, and welfare using a search-and-matching model with heterogeneous agents and on-the-job human capital accumulation. We calibrate the general equilibrium model to match key moments concerning unemployment, wage and wealth distributions, as well as the distribution of EITC and transfers. In addition, unemployment insurance benefits are related to pre-unemployment earnings and subject to exhaustion, after which agents can only rely on transfers and savings. First, we show that existing transfers hamper economic activity but provide sizeable welfare gains. Next, we show that a universal basic income of nearly $12,500 to each household per year, which replaces all existing transfer programs and unemployment benefits, can lead to small aggregate welfare gains. These welfare gains mostly accrue to less skilled individuals despite their sizable fall in wages, and the overall rise in skill premia and wage inequality. Albeit the extra burden of higher taxes to finance UBI, we show that the increased action in hiring is a key channel though which outcomes for low education groups improve with the reform. However, if we keep the UI benefits in place, the positive effects on job creation vanish and UBI does not improve upon the current system

Social Media and Citation Metrics

Quantifying scholarly output via traditional citation metrics is the time-honored method to gauge academic success. However, as the tentacles of social media spread into professional personas, scholars are interacting more frequently and more meaningfully with these tools. Measuring the influence and impact of scholarly engagement with online tools and networks is gaining importance in academia today. Assessing the impact of a scholar’s work can be measured by evaluating several factors including the number of peer-reviewed publications, citations to these publications and the influence of the publications. These metrics take a relatively long time to accumulate, some are available only via subscription resources, and often measure influence only on a specific scientific community. While these accepted tools provide a means to weigh scholarly output, they do not tell the entire story. Increasingly, scholars are engaging with social media in a professional capacity. From following tweets of fellow conference attendees to hearing about newly published papers, researchers are becoming more reliant upon crowdsourced peer review. As the acceptance of social media and online tools has progressed, interest in employing these tools to gauge academic success has been amplified. There is some very interesting work being done on alternative scholarly metrics, or altmetrics (Priem, Taraborelli, Groth, & Neylon, Cameron, 2010). Some of the more mature tools will be discussed, along with current research that connects social networks with citation metrics (Eysenbach, 2011). In addition, acceptance of these tools in scientific disciplines will be addressed, along with the methods that information professionals can use to help facilitate their use

Zotero

Zotero is a free, open access, citation management tool that allows users to store, manage and cite bibliographic references. Zotero can format citations in many different styles and lets users insert citations within word processing software. Zotero allows for easy collaboration between multiple authors and enables users to create private or shared reading lists. Zotero is a project of the Roy Rosenzweig Center for History and New Media. At the completion of this class, participants will be able to: Install Zotero Collect and organize citations Create formatted bibliographies and insert citations into documents Collaborate with colleagues to create reading lists and/or jointly author paper