Light source selection for a solar simulator for thermal applications: A review

Solar simulators are used to test components and systems under controlled and repeatable conditions, often in locations with unsuitable insolation for outdoor testing. The growth in renewable energy generation has led to an increased need to develop, manufacture and test components and subsystems for solar thermal, photovoltaic (PV), and concentrating optics for both thermal and electrical solar applications. At the heart of any solar simulator is the light source itself. This paper reviews the light sources available for both low and high-flux solar simulators used for thermal applications. Criteria considered include a comparison of the lamp wavelength spectrum with the solar spectrum, lamp intensity, cost, stability, durability, and any hazards associated with use. Four main lamp types are discussed in detail, namely argon arc, the metal halide, tungsten halogen lamp, and xenon arc lamps. In addition to describing the characteristics of each lamp type, the popularity of usage of each type over time is also indicated. This is followed by guidelines for selecting a suitable lamp, depending on the requirements of the user and the criteria applied for selection. The appropriate international standards are also addressed and discussed. The review shows that metal halide and xenon arc lamps predominate, since both provide a good spectral match to the solar output. The xenon lamp provides a more intense and stable output, but has the disadvantages of being a high-pressure component, requiring infrared filtering, and the need of a more complex and expensive power supply. As a result, many new solar simulators prefer metal halide lamps

Self-Portraiture and Commodification in the Work of Huron/Wendat Artist Zacharie Vincent, aka “Le Dernier Huron”

Zacharie Vincent, or Tehariolin (1815–1886), was a Huron/Wendat artist from the Wendake reserve community near Quebec City. He took up painting in 1838 after posing for a portrait by celebrated French-Canadian artist Antoine Plamondon, entitled “Le dernier Huron” (“The Last Huron”). Tehariolin’s extant works include landscapes and local-color sketches, but are most notable for his many self-portraits, in which he depicted himself wearing chiefly accessories such as medals and headdresses. Since the 1980s his art has been the subject of growing attention by scholars, mostly in Quebec and writing in French, but Tehariolin is still little known in the United States. This essay examines, first, how the epithet “Last Huron,” typical of the “vanishing Indian” ideology of the time, was appropriated into the cultural struggle of Francophone canadiens against imperial British hegemony during a time of violent rebellion and repression in Canada; and second, how Tehariolin’s artwork became commodified in the manner of products manufactured for a mass market, much like the moccasins, snowshoes, and other items manufactured in Wendake. During the later nineteenth century, photography made possible the mass reproduction of images of Tehariolin, such as in postcards produced by Quebec photographer L. P. Vallée in the 1870s. Zacharie Vincent was not the last Huron, but his livelihood as an artist suffered even as his image proliferated. The cliché of “the Last of his Tribe” was undercut by the consumer culture that had often exploited the ideology for its own colonialist purposes

Workshop report: Strategies for setting occupational exposure limits for engineered nanomaterials

AbstractOccupational exposure limits (OELs) are important tools for managing worker exposures to chemicals; however, hazard data for many engineered nanomaterials (ENMs) are insufficient for deriving OELs by traditional methods. Technical challenges and questions about how best to measure worker exposures to ENMs also pose barriers to implementing OELs. New varieties of ENMs are being developed and introduced into commerce at a rapid pace, further compounding the issue of OEL development for ENMs. A Workshop on Strategies for Setting Occupational Exposure Limits for Engineered Nanomaterials, held in September 2012, provided an opportunity for occupational health experts from various stakeholder groups to discuss possible alternative approaches for setting OELs for ENMs and issues related to their implementation. This report summarizes the workshop proceedings and findings, identifies areas for additional research, and suggests potential avenues for further progress on this important topic

Timely Colonoscopy After Positive Fecal Immunochemical Tests in the Veterans Health Administration: A Qualitative Assessment of Current Practice and Perceived Barriers.

IntroductionThe Veterans Health Administration introduced a clinical reminder system in 2018 to help address process gaps in colorectal cancer screening, including the diagnostic evaluation of positive fecal immunochemical test (FIT) results. We conducted a qualitative study to explore the differences between facilities who performed in the top vs bottom decile for follow-up colonoscopy.MethodsSeventeen semistructured interviews with gastroenterology (GI) providers and staff were conducted at 9 high-performing and 8 low-performing sites.ResultsWe identified 2 domains, current practices and perceived barriers, and most findings were described by both high- and low-performing sites. Findings exclusive to 1 group mainly pertained to current practices, especially arranging colonoscopy for FIT-positive patients. We observed only 1 difference in the perceived barriers domain, which pertained to primary care providers.DiscussionThese results suggest that what primarily distinguishes high- and low-performing sites is not a difference in barriers but rather in the GI clinical care process. Developing and disseminating patient education materials about the importance of diagnostic colonoscopy, eliminating in-person precolonoscopy visits when clinically appropriate, and involving GI in missed colonoscopy appointments and outside referrals should all be considered to increase follow-up colonoscopy rates. Our study illustrates the challenges of performing a timely colonoscopy after a positive FIT result and provides insights on improving the clinical care process for patients who are at substantially increased risk for colorectal cancer