9,273 research outputs found

    Converting rain into drinking water: Quality issues and technological advances

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    With growing pressures on water supplies worldwide, rainwater harvesting is increasingly seen as a viable option to provide drinking water to an ever expanding population, particularly in developing countries. However, rooftop runoff is not without quality issues. Microbiological and chemical contamination have been detected in several studies, well above local and international guidelines, posing a health risk for consumers. Our research explores the use of silver ions, combined with conventional filtration and settling mechanisms, as a safe and affordable model for purification that can be applied on a small scale. The complete systems were installed and tested in rural communities in a Mexican semi-arid region. Efficiencies up to 99.9% were achieved in the removal of indicator microorganisms, with a marked exception where cross-contamination from external seepage occurs. Sites without overhanging branches or with relatively clean surfaces show an absence of total coliforms in the untreated runoff, compared with others where values as high as 1,650 CFU/100 ml were recorded. Thus, given adequate maintenance, the system can successfully deliver high quality drinking water, even when storage is required for long periods of time. © IWA Publishing 2011

    Millet agriculture dispersed from Northeast China to the Russian Far East: integrating archaeology, genetics, and linguistics

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    Broomcorn and foxtail millets were being cultivated in the West Liao River basin in Northeast China by at least the sixth millennium BCE. However, when and how millet agriculture spread from there to the north and east remains poorly understood. Here, we trace the dispersal of millet agriculture from Northeast China to the Russian Far East and weigh demic against cultural diffusion as mechanisms for that dispersal. We compare two routes for the spread of millet into the Russian Far East discussed in previous research—an inland route across Manchuria, and a coastal/inland route initially following the Liaodong Peninsula and Yalu River—using an archaeological dataset including millet remains, pottery, stone tools, spindle whorls, jade and figurines. We then integrate the archaeological evidence with linguistic and genetic findings in an approach we term ‘triangulation’. We conclude that an expansion of agricultural societies in Northeast China during the Middle to Late Hongshan (4000–3000 BCE) coincided with the arrival of millet cultivation in eastern Heilongjiang and the Primorye province of the Russian Far East. Our findings support the inland, Manchuria route for the dispersal of millet to the Primorye and suggest that, as well as long-distance cultural exchange, demic diffusion was also involved. Our results are broadly compatible with the farming/language dispersal hypothesis and consistent with a link between the spread of millet farming and proto-Tungusic, the language ancestral to the contemporary Tungusic languages, in late Neolithic Northeast Asia. © 2020 The Author

    Swept-wavelength mid-infrared fiber laser for real-time ammonia gas sensing

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    The mid-infrared (mid-IR) spectral region holds great promise for new laser-based sensing technologies, based on measuring strong mid-IR molecular absorption features. Practical applications have been limited to date, however, by current low-brightness broadband mid-IR light sources and slow acquisition-time detection systems. Here, we report a new approach by developing a swept-wavelength mid-infrared fiber laser, exploiting the broad emission of dysprosium and using an acousto-optic tunable filter to achieve electronically controlled swept-wavelength operation from 2.89 to 3.25 {\mu}m (3070-3460 cm^-1). Ammonia (NH3) absorption spectroscopy is demonstrated using this swept source with a simple room-temperature single-pixel detector, with 0.3 nm resolution and 40 ms acquisition time. This creates new opportunities for real-time high-sensitivity remote sensing using simple, compact mid-IR fiber-based technologies.Comment: Invited article for APL Photonic

    The Place of Widening Participation

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    This chapter reports on a small-scale study to explore the learning careers of mature, non-traditionally qualified students. It reveals how they (re)engage with learning, and their transition from studying on a bespoke access course delivered in a university to study at undergraduate level. The study highlights the barriers and challenges students overcome and identifies their motivations and dispositions to learning. Whilst the majority of access courses are delivered in further education colleges, a small number of universities deliver bespoke access courses. These courses, which are usually designed to facilitate progression within the institution, enable students to experience teaching and learning in a university setting, facilities and support services. The research adopted a qualitative approach, using interviews as the main method of data collection. Emerging findings reveal that (re)engaging with education and the transition from ‘access student’ to undergraduate student is not seamless and without challenges. Such students ‘often undergo a unique and profound experience’ (Burnell, 2015:6) as they enter this new space which provides an opportunity to create new social and class-related identities. The transition to undergraduate study is easier when learners are familiar with the routines and rhythms of higher education in general and the facilities and services of a particular institution

    Alien Registration- Ellis, Maude I. (Bath, Sagadahoc County)

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    https://digitalmaine.com/alien_docs/9518/thumbnail.jp

    SOYBEANS QUALITY PRICE DIFFERENTIALS FROM AN ELEVATOR'S PERSPECTIVE

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    Soybean prices are determined by interaction between various factors. At an elevator, discount prices for unique characteristics can range from 0.02 cents per bushel to 7.71 cents per bushel of soybeans. This variation suggests that producers of soybeans need quality-characteristic specific information concerning soybeans pricing at the market. This study uses a hedonic model to evaluate price differentials associated with soybean quality based on grain elevator data during the 1998 production period. Foreign material, moisture, bean damage, and net weight were found to significantly influence the cash price of soybeans.hedonic, quality, discount, Crop Production/Industries, Demand and Price Analysis,
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