Electronic Transport in Thermoelectric Bismuth Telluride

An experimental investigation of the electronic transport properties of bismuth telluride nanocomposite materials is presented. The primary transport measurements are electrical conductivity, Seebeck coefficient and Hall effect. An experimental apparatus for measuring Hall effect and electrical conductivity was designed, constructed and tested. Seebeck coefficient measurements were performed on a commercial instrument. The Hall effect and Seebeck coefficient measurements are two of the most important tools for characterizing thermoelectric materials and are widely used in the semiconductor industry for determining carrier types, carrier concentration and mobility. Further, these transport parameters are used to determine the thermal to electrical conversion efficiency of a thermoelectric material. The Boltzmann transport equation was used to analyze the Seebeck coefficient, carrier mobility and electrical conductivity as a function of carrier concentration for eleven samples. The relationship between the electronic transport and material/composite composition is discussed

Seguin Historical Museum : an internship report

This internship involved the creation of an historical maritime museum on an island off the Maine coast. The museum documents the history of Seguin Lightstation from 1795 to 1993. This paper describes the process of creating the museum, as well as the political and logistical complications of this particular site. The museum was created in conjunction with The Friends of Seguin Island, a nonprofit organization located in Georgetown, Maine, to promote public awareness of the lightstation\u27s historic value

Giant freshwater prawn farming in the Philippines

Freshwater prawn thrives in inland waters like rivers, lakes, swamps, irrigation canals, estuaries and even in rivers upstream. A recent survey in Luzon Island, Philippines identified 12 species of freshwater prawn found in the island (Agasen, unpublished). The country’s interest on freshwater prawn fishery started in 1914 as explained by Cowles (1914), when the freshwater prawn was recognized as one of the important fisheries during that time. In late 1976, trials were made to culture the freshwater prawn, however, the efforts were not sustained. These trials were conducted in Misamis Oriental, Mindanao between 1976-1979 by Dejarme et al., with the collection of wild spawners and the subsequent rearing of M. rosenbergii hatchlings. In 1981, a local banker-industrialist established a 100-hectare commercial Macrobrachium farm in Sta. Rosa, Nueva Ecija and a hatchery in Bulacan. Services of experts from Israel were tapped for the project. Marketable prawns were sold live in Metro Manila utilizing in-house retail outlets. After a few years, the company diversified their operations to include tilapia culture. However, even the diversification attempt failed to save the first venture of commercial Macrobrachium rosenbergii production in the Philippines

Young people, social media, social network sites and sexual health communication in Australia: ‘this is funny, you should watch it

Social media and social network sites (SNS) are an evolving area for sexual health communication with young people. They present opportunities and challenges for sexual health professionals and young people alike, such as learning through interactivity and addressing concerns about privacy. In this article, we present and discuss the findings from six rural and urban focus groups with young people in Australia about the use of social media and SNS for sexual health communication. We discuss a number of issues related to the use of social media and SNS for sexual health communication, such as concerns about bullying, privacy, and the stigma attached to sexual health

On-chip optical parametric oscillation into the visible: generating red, orange, yellow, and green from a near-infrared pump

Optical parametric oscillation (OPO) in a microresonator is promising as an efficient and scalable approach to on-chip coherent visible light generation. However, so far only red light at < 420 THz (near the edge of the visible band) has been reported. In this work, we demonstrate on-chip OPO covering > 130 THz of the visible spectrum, including red, orange, yellow, and green wavelengths. In particular, using a pump laser that is scanned 5 THz in the near-infrared from 386 THz to 391 THz, the signal is tuned from the near-infrared at 395 THz to the visible at 528 THz, while the idler is tuned from the near-infrared at 378 THz to the infrared at 254 THz. The widest signal-idler separation we demonstrate of 274 THz corresponds to more than an octave span and is the widest demonstrated for a nanophotonic OPO to date. Our work is a clear demonstration of how nonlinear nanophotonics can transform light from readily accessible compact near-infrared lasers to targeted visible wavelengths of interest, which is crucial for field-level deployment of spectroscopy and metrology systems.Comment: 6 pages, 5 figure

A universal frequency engineering tool for microcavity nonlinear optics: multiple selective mode splitting of whispering-gallery resonances

Whispering-gallery microcavities have been used to realize a variety of efficient parametric nonlinear optical processes through the enhanced light-matter interaction brought about by supporting multiple high quality factor and small modal volume resonances. Critical to such studies is the ability to control the relative frequencies of the cavity modes, so that frequency matching is achieved to satisfy energy conservation. Typically this is done by tailoring the resonator cross-section. Doing so modifies the frequencies of all of the cavity modes, that is, the global dispersion profile, which may be undesired, for example, in introducing competing nonlinear processes.Here, we demonstrate a frequency engineering tool, termed multiple selective mode splitting (MSMS), that is independent of the global dispersion and instead allows targeted and independent control of the frequencies of multiple cavity modes. In particular, we show controllable frequency shifts up to 0.8 nm, independent control of the splitting of up to five cavity modes with optical quality factors $\gtrsim 10^5$, and strongly suppressed frequency shifts for untargeted modes. The MSMS technique can be broadly applied to a wide variety of nonlinear optical processes across different material platforms, and can be used to both selectively enhance processes of interestand suppress competing unwanted processes.Comment: 13 pages, 8 figure