370 research outputs found
Glass Frit Filters for Collecting Metal Oxide Nanoparticles
Filter disks made of glass frit have been found to be effective as means of high-throughput collection of metal oxide particles, ranging in size from a few to a few hundred nanometers, produced in gas-phase condensation reactors. In a typical application, a filter is placed downstream of the reactor and a valve is used to regulate the flow of reactor exhaust through the filter. The exhaust stream includes a carrier gas, particles, byproducts, and unreacted particle-precursor gas. The filter selectively traps the particles while allowing the carrier gas, the byproducts, and, in some cases, the unreacted precursor, to flow through unaffected. Although the pores in the filters are much larger than the particles, the particles are nevertheless trapped to a high degree: Anecdotal information from an experiment indicates that 6-nm-diameter particles of MnO2 were trapped with greater than 99-percent effectiveness by a filtering device comprising a glass-frit disk having pores 70 to 100 micrometer wide immobilized in an 8-cm-diameter glass tube equipped with a simple twist valve at its downstream end
Factors Influencing Household Uptake of Improved Solid Fuel Stoves in Low- and Middle-Income Countries: A Qualitative Systematic Review
Household burning of solid fuels in traditional stoves is detrimental to health, the environment and development. A range of improved solid fuel stoves (IS) are available but little is known about successful approaches to dissemination. This qualitative systematic review aimed to identify factors that influence household uptake of IS in low- and middle-income countries. Extensive searches were carried out and studies were screened and extracted using established systematic review methods. Fourteen qualitative studies from Asia, Africa and Latin-America met the inclusion criteria. Thematic synthesis was used to synthesise data and findings are presented under seven framework domains. Findings relate to user and stakeholder perceptions and highlight the importance of cost, good stove design, fuel and time savings, health benefits, being able to cook traditional dishes and cleanliness in relation to uptake. Creating demand, appropriate approaches to business, and community involvement, are also discussed. Achieving and sustaining uptake is complex and requires consideration of a broad range of factors, which operate at household, community, regional and national levels. Initiatives aimed at IS scale up should include quantitative evaluations of effectiveness, supplemented with qualitative studies to assess factors affecting uptake, with an equity focus
Factors Influencing Household Uptake of Improved Solid Fuel Stoves in Low- and Middle-Income Countries: A Qualitative Systematic Review
Household burning of solid fuels in traditional stoves is detrimental to health, the environment and development. A range of improved solid fuel stoves ( IS) are available but little is known about successful approaches to dissemination. This qualitative systematic review aimed to identify factors that influence household uptake of IS in low- and middle-income countries. Extensive searches were carried out and studies were screened and extracted using established systematic review methods. Fourteen qualitative studies from Asia, Africa and Latin-America met the inclusion criteria. Thematic synthesis was used to synthesise data and findings are presented under seven framework domains. Findings relate to user and stakeholder perceptions and highlight the importance of cost, good stove design, fuel and time savings, health benefits, being able to cook traditional dishes and cleanliness in relation to uptake. Creating demand, appropriate approaches to business, and community involvement, are also discussed. Achieving and sustaining uptake is complex and requires consideration of a broad range of factors, which operate at household, community, regional and national levels. Initiatives aimed at IS scale up should include quantitative evaluations of effectiveness, supplemented with qualitative studies to assess factors affecting uptake, with an equity focus
Environmental tipping points and food system dynamics: Main report
First paragraph: Environmental tipping points occur when there are step changes in the way the biophysical world works – whether loss of soil fertility, collapse of a fishing stock, or sudden changes in weather patterns, such as those that caused the grasslands in North Africa to become deserts, 6000 years ago. These non-linear shifts arise following a critical degree of change, resulting from either many small cumulative changes or one large shock, “tipping” the system over a threshold and into a new stable state. Entering an alternative stable state is associated with a change to system function, usually being difficult to reverse or “tip” back into the original state. Increasingly we recognise that human-environment interactions are affecting the likelihood that critical thresholds for tipping points will be crossed, leading to step-changes in the provision of environmental goods and services, and impacting upon food security
The Birchwood Junk Food Cafe, Skelmersdale
The University of Manchester conducted an evaluation of the Birchwood Junk Food Cafe, Skelmersdale, to assess the additional benefits of their adapted approach. A mixed methods evaluation was conducted, including interviews and questionnaires with both customers and those running the cafe. This highlighted benefits of the cafe and the impact of the cafe on its volunteers and customers. Key messages: Junk Food Cafes have the potential to have a positive impact on public health. Junk Food Cafes have the potential to help combat food poverty and social isolation in deprived communities
Pneumonia and exposure to household air pollution in children under the age of 5 years in rural Malawi findings from the Cooking And Pneumonia Study
Background Exposure to household air pollution is associated with an increased risk of pneumonia in children in low- and middle-income countries, however exposure-response data are limited and there are uncertainties around the extent to which biomass-fueled cookstoves can reduce these exposures. Research question What is the association between exposure to household air pollution and pneumonia in children under the age of 5 years in rural Malawi and what are the effects of a biomass-fueled cookstove intervention on personal exposure to household air pollution? Study design and methods We measured personal exposure to carbon monoxide (CO) [48 hours of continuous measurement and transcutaneous carboxyhemoglobin (COHb)] 6-monthly in children participating in a cluster-randomised controlled trial of a cleaner-burning biomass-fueled cookstove intervention to prevent pneumonia in children under the age of 5 years in rural Malawi – the Cooking And Pneumonia Study (CAPS). Exposure-response and multi-variable analyses were done. Results We recruited 1805 (928 intervention; 877 control) children (mean age 25.6 months, 50.6% female). We found no evidence of an association between exposure to CO (IRR=1.0 95% CI:0.967-1.014; p=0.53) or COHb (IRR=1.00 95% CI:0.993-1.003; p=0.41)) in children who experienced pneumonia versus those who did not. Median exposure to CO in the intervention and control groups was was 0.34 ppm (IQR 0.15-0.81) and 0.37 ppm (IQR 0.15-0.97), respectively. The group difference in means was 0.46 (95% CI:-0.95-0.012; p=0.06). Interpretation Exposure to CO in our population was low with no association seen between exposure to CO and pneumonia incidence and no effect of the CAPS intervention on these exposures. These findings suggest that CO may not be an appropriate measure of household air pollution exposure in settings like rural Malawi and that there is a need to develop ways to directly measure particulate matter exposures in young children instead
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