Carbon, Cookstoves, and Kitchens: Case Studies of Fuelwood Use and the Potential for Ethanol Substitutability in Rural India, Vietnam, and Tanzania

Fuelwood constitutes the primary domestic cooking fuel in many rural communities throughout the Global South. Unsustainable levels of fuelwood consumption, however, contribute not only to local forest degradation but also to global climate change through the release of black carbon and carbon dioxide into the atmosphere. Moreover, as a driver of indoor air pollution, it also negatively affects human health. Indoor air pollution linked to cooking smoke is among the leading causes of preventable respiratory disease, and negatively impacts women and children through disproportionate and repeated exposure. While many cleaner and more efficient alternate stove designs have been developed for use in fuelwood-dependent communities, culturally-based user incompatibilities and technical design problems can lead to lack of widespread adoption. Although fuelwood dependence has also been offset by the availability of subsidized commercially-available fuels such as kerosene or liquid petroleum gas (LPG), the need persists for a clean, efficient, locally available, and sustainable fuel source for use in household cooking. This poster presents the results of three related, pilot project case studies about the potential for alcohol-fueled stoves to serve as a pathway to fuelwood substitution. The poster explores questions of cultural feasibility and the related roles of gender/class/ethnicity dynamics within a community, cooking and fuel preferences of stove users, and religious considerations related to non-consumptive alcohol use. Our study raises important issues for advocates of alternative technologies to consider, including the potential for resource capture by elites, openings for promotion of gender equity, and opportunities for socially and environmentally sustainable development

Simulations of shell galaxies with GADGET-2: Multi-generation shell systems

As the missing complement to existing studies of shell galaxies, we carried out a set of self-consistent N-body simulations of a minor merger forming a stellar shell system within a giant elliptical galaxy. We discuss the effect of a phenomenon possibly associated with the galaxy merger simulations --- a presence of multiple generations of shells.Comment: 2 pages, 1 figure, to appear in the Proceedings of JENAM 2010, Symposium 2: "Environment and the formation of galaxies: 30 years later

Microstructural Modeling of Collagen Network Mechanics and Interactions with the Proteoglycan Gel in Articular Cartilage

Cartilage matrix mechanical function is largely determined by interactions between the collagen fibrillar network and the proteoglycan gel. Although the molecular physics of these matrix constituents have been characterized and modern imaging methods are capable of localized measurement of molecular densities and orientation distributions, theoretical tools for using this information for prediction of cartilage mechanical behavior are lacking. We introduce a means to model collagen network contributions to cartilage mechanics based upon accessible microstructural information (fibril density and orientation distributions) and which self-consistently follows changes in microstructural geometry with matrix deformations. The interplay between the molecular physics of the collagen network and the proteoglycan gel is scaled up to determine matrix material properties, with features such as collagen fibril pre-stress in free-swelling cartilage emerging naturally and without introduction of ad hoc parameters. Methods are developed for theoretical treatment of the collagen network as a continuum-like distribution of fibrils, such that mechanical analysis of the network may be simplified by consideration of the spherical harmonic components of functions of the fibril orientation, strain, and stress distributions. Expressions for the collagen network contributions to matrix stress and stiffness tensors are derived, illustrating that only spherical harmonic components of orders 0 and 2 contribute to the stress, while orders 0, 2, and 4 contribute to the stiffness. Depth- and compression-dependent equilibrium mechanical properties of cartilage matrix are modeled, and advantages of the approach are illustrated by exploration of orientation and strain distributions of collagen fibrils in compressed cartilage. Results highlight collagen-proteoglycan interactions, especially for very small physiological strains where experimental data are relatively sparse. These methods for determining matrix mechanical properties from measurable quantities at the microscale (composition, structure, and molecular physics) may be useful for investigating cartilage structure-function relationships relevant to load-bearing, injury, and repai