198,060 research outputs found
International standards: filters for vehicular applications
No full textIn the second part of their examination of international standards for particulate and gaseous contaminant air filters, Paolo Tronville and Richard Rivers look at filters for vehicular applications
Fluvial contributions of nutrient salts, dissolved trace elements and organic carbon to the sea by pristine temperate rivers (SW Europe).
No full textBernárdez, P., Ospina-Alvarez, N., Caetano, M., & Prego, R. (2013). Fluvial contributions of nutrient salts, dissolved trace elements and organic carbon to the sea by pristine temperate rivers (SW Europe). Environmental Chemistry, 10(1), 42–53. doi:http://dx.doi.org/10.1071/EN1212
Anthropologues et missionnaires avant la rupture. Une conférence de W. H. R. Rivers
No full textRivers William Halse Rivers, Pulman Bertrand. Anthropologues et missionnaires avant la rupture. Une conférence de W. H. R. Rivers. In: Gradhiva : revue d'histoire et d'archives de l'anthropologie, n°7, 1989. pp. 73-86
Standards I:filters for buildings and gas turbines
No full textThe development of standards for the filtration industry continues to take prominence worldwide. In the first of a two part feature, Paolo Tronville and Richard Rivers examine the development of standards for filters used in general building ventilation, as well as for gas turbine intake air cleaning
Towards a More Comprehensive Understanding of Rivers
No full textFor several years now there has been widespread and deep concern at the deplorable state of the rivers Yamuna and Ganga. From time to time, there have also been disturbing accounts of the decline of certain other rivers. Very occasionally, there are reports about a few rivers that have remained relatively healthy and unpolluted. The circumstances and developments involved in those vague perceptions, both positive and negative, were sought to be explored in a series of monthly lectures/presentations. The present book is the outcome of that programme. Papers in finished form were asked for and some additional papers were obtained. The major part of the book consists of a series of chapters that give an account of the present condition of many of our rivers and of the factors that have had an impact on that condition
Island Rivers
No full textAnthropologists have written a great deal about the coastal adaptations and seafaring traditions of Pacific Islanders, but have had much less to say about the significance of rivers for Pacific island culture, livelihood and identity. The authors of this collection seek to fill that gap in the ethnographic record by drawing attention to the deep historical attachments of island communities to rivers, and the ways in which those attachments are changing in response to various forms of economic development and social change. In addition to making a unique contribution to Pacific island ethnography, the authors of this volume speak to a global set of issues of immense importance to a world in which water scarcity, conflict, pollution and the degradation of riparian environments afflict growing numbers of people. Several authors take a political ecology approach to their topic, but the emphasis here is less on hydro-politics than on the cultural meaning of rivers to the communities we describe. How has the cultural significance of rivers shifted as a result of colonisation, development and nation-building? How do people whose identities are fundamentally rooted in their relationship to a particular river renegotiate that relationship when the river is dammed to generate hydro-power or polluted by mining activities? How do blockages in the flow of rivers and underground springs interrupt the intergenerational transmission of local ecological knowledge and hence the ability of local communities to construct collective identities rooted in a sense of place
New method to measure the mechanical collection mechanisms of full-scale air filters
No full textAir filters are chosen for the minimum particle-capture efficiency they can provide in a specific application. Some media can achieve high efficiencies at low resistance to air flow by adding electrostatic charges on fairly coarse fibers. However, prolonged filter exposure to fine particles reduces the electrostatic enhancement effect. The filter efficiency must then rely mainly on mechanical collection mechanisms, and can fall well below the initial value. It is useful to test filter media when the effect of electrostatic charges is eliminated. To estimate the efficiency drop that may occur, air filter test standards include filter conditioning procedures to inhibit the effect of electrostatic charges. These treatments should leave only particle capture effects from mechanical collection mechanisms such as sieving, aerodynamics and diffusion, but not reduce or enhance these effects. EN779:2012 and ISO 21220:2009 describe such a conditioning treatment for filter media, and ASHRAE 52.2-2012 describes one for full-scale filters. The ASHRAE 52.2-2012 optional treatment suggests that air filters be exposed to a potassium chloride aerosol having approximately 35 nm count mean diameter. Following the charge-elimination treatment, procedures measuring efficiency as a function particle size are performed. In ISO/TS 21220:2009 and EN779:2012 the discharging treatment is also mandatory, but is performed on samples of the media used to manufacture the filter. This treatment requires a 2 minute soak in essentially pure isopropyl alcohol (IPA), after which the media samples are dried for 24 hours before further tests. This method presents problems, namely, that soaking in a liquid may alter the mechanical efficiency of media, and that samples of media may not be representative of the media used in the full-scale filter. A new approach, developed by T. Hayashi in Japan, eliminated electrostatic effects in electret-enhanced media sheets by exposure to IPA vapor for 16 hours or longer. This procedure was successfully duplicated by J. Cai in China, and at the Politecnico di Torino. ISO/TC142/WG9 in 2010 ran an inter-laboratory comparison to assess this procedure, and in 2011 organized another comparison which extended the method to full-scale filters. The full-scale tests have included three different types of air filters, comparing the results with the other approaches previously mentioned. These results will be useful for revising the current ISO 29461-1 test method and also for developing the new ISO 16890 series for general ventilation applications. Here we summarize the data obtained at the Politecnico di Torino, and describe the new test protocol that could be adopted by future international filter test standard
Global Standards for Filter Testing
No full textThe ISO and the IEC are cooperating with the European Union's CEN (see Table 1 for acronym definitions) and other standards organizations to create global standards for building air filters. The United States, through ANSI, is represented on ISO Technical Committee (TC) 142, Cleaning Equipment for Air and Other Gases, Working Group (WG) 3, General Ventilation Filters. This group is writing an ISO standard for a test method for general ventilation air filters. Several other countries are participating and the list is being updated continuously (see ISO/TC 142 Web site for the latest information
Valuing agricultural externalities in Canterbury rivers and streams
No full textWater quality and quantity concerns in Canterbury are intrinsically related to agriculture. Monetary values for impacts on streams and rivers is lacking in policy debate. This paper employs choice modelling to estimate values of three impacts on rivers and streams in Canterbury associated with agriculture: health risks of E coli from animal waste, ecological effects of excess nutrients, and low-flow impacts of irrigation. This study provides a valuation of outcomes for public policy implemented in Canterbury such as The Dairy and Clean Streams Accord, Living Streams, and The Restorative Programme for Lowland Streams.non-market-valuation, choice experiment, agricultural externalities, New Zealand, Agricultural and Food Policy, Environmental Economics and Policy, Food Consumption/Nutrition/Food Safety, Health Economics and Policy,
Predicting Resistance of Air Filter Media Having Log-Normal Fiber Diameter Distribution and Random 2-Dimension Spacing by CFD Simulation
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