Improvement of kiln design and combustion/carbonization timing to produce charcoal from agricultural waste in Developing countries

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (leaf 25).Current economic conditions in third world countries like Haiti are so poor that the majority of the population has no access to energy sources that people in the first world take for granted. In Haiti the last two percent of the forests are being cut down to provide energy for basic cooking to survive. In response to the situation, MIT professors and students are designing a multi-step process for making charcoal briquettes from local agricultural waste products, or biomass. The process involves the combustion and carbonization of biomass at sustained high temperature in an air-tight metal barrel kiln to produce char. The char produced from Haiti's main agricultural waste product, bagasse, must be powderized, mixed with a binder, compressed into briquettes, and finally baked. The purpose of the thesis was to improve on key areas of the charcoal making process. The goals were to: conduct and investigation into alternative kiln layouts; address safety concerns with water boiling, briquette baking, and bottom venting; design of a method for uniform and complete briquette baking using heat from the carbonizing kiln; and gain a better understanding of the importance combustion timing and sealing.(cont.) Design for affordable, low level manufacturing would be an important requirement as well. The results of the thesis were: an analysis of possible kiln designs based on the supplies typically available in developing countries; improvements to safety by using wire tethers on kiln hardware to allow kiln operators to keep a safe distance; a proposed new design for a briquette baking box with multiple briquette banks; and combustion timing and kiln insulation techniques to maximize char output.by Jason A. Martinez.S.B

Investigation of (E, 2E) Collisions and Related Phenomena

In this thesis I investigate (e, 2e) processes, or electron impact ionization, using several theoretical methods. I first examine the problem using the Born approximations, particularly the Distorted Wave Born Approximation (DWBA), focusing on the underlying processes that dominate for ionization of the 2p state of Argon and Magnesium. I investigate as well the ionization of helium and hydrogen and use the simplicity of the approximation to probe the incident particle effects on the Helium cross section. In both cases the results are compared with experiment. I also produce cross section results for ions near threshold, a regime that is currently under experimental investigation. In the second part of this thesis, I develop an ab initio method for doing these calculations called the X2e method. This is described in full, including derivation of the important features of the method. Preliminary results are presented in comparison with established theory

Specification of high-level application programming interfaces (SemSorGrid4Env)

This document defines an Application Tier for the SemsorGrid4Env project. Within the Application Tier we distinguish between Web Applications - which provide a User Interface atop a more traditional Service Oriented Architecture - and Mashups which are driven by a REST API and a Resource Oriented Architecture. A pragmatic boundary is set to enable initial development of Web Applications and Mashups; as the project progresses an evaluation and comparison of the two paradigms may lead to a reassessment of where each can be applied within the project, with the experience gained providing a basis for general guidelines and best practice. Both Web Applications and Mashups are designed and delivered through an iterative user-centric process; requirements generated by the project case studies are a key element of this approach

Geometric stability conditions under autoequivalences and applications: Elliptic Surfaces

On a Weierstrass elliptic surface, we describe the action of the relative Fourier-Mukai transform on the geometric chamber of $\mathrm{Stab}(X)$, and in the K3 case we also study the action on one of its boundary components. Using new estimates for the Gieseker chamber we prove that Gieseker stability for polarizations on certain Friedman chamber is preserved by the derived dual of the relative Fourier-Mukai transform. As an application of our description of the action, we also prove projectivity for some moduli spaces of Bridgeland semistable objects.Comment: 32 pages, comments welcome

Implementation and Deployment of a Library of the High-level Application Programming Interfaces (SemSorGrid4Env)

The high-level API service is designed to support rapid development of thin web applications and mashups beyond the state of the art in GIS, while maintaining compatibility with existing tools and expectations. It provides a fully configurable API, while maintaining a separation of concerns between domain experts, service administrators and mashup developers. It adheres to REST and Linked Data principles, and provides a novel bridge between standards-based (OGC O&M) and Semantic Web approaches. This document discusses the background motivations for the HLAPI (including experiences gained from any previously implemented versions), before moving onto specific details of the final implementation, including configuration and deployment instructions, as well as a full tutorial to assist mashup developers with using the exposed observation data

Finite Element Analysis of Steel-Concrete Composite Floor Systems under Traveling Fires

Traveling fires occur in large open-plan compartment and have been observed in many fire accidents including the First Interstate Bank fire in Los Angeles in 1988, the One Meridian Plaza fire in Philadelphia in 1991, and the World Trade Center Building 7 fire in New York City in 2001. Despite the significant structural damage observed in these incidents, existing fire safety codes do not have regulations dedicated to ensuring the fire safety of large open-plan compartments, nor are traveling fires explicitly considered in the fire design process. To address this deficiency, the dissertation presents a computational study aimed at better understanding the thermal and structural response of steel-concrete composite (SCC) floor systems exposed to traveling fires. Improvements to the finite element modeling of SCC floor systems were developed as part of the dissertation work. Specifically, a formal macro-modeling approach for SCC floor systems was presented, which addresses a modeling error that has remained largely unreported in the research literature. Using this modeling approach, a numerical analysis of an axially-restrained SCC beam was performed. The results showed that failure of a restrained SCC beam is heavily influenced by its span length: a composite beam with a short span tends to fail in the compressive beam-column stage, while a composite beam with a longer span tends to fail in the tensile catenary stage. Additionally, conditions which are favorable for the mobilization of tensile catenary action were determined, which provides structural engineers with the information required to improve the fire resistance of SCC beams. A fomulation for an elevated-temperature tension stiffening model for use in the finite element modeling of SCC floor systems was also developed. Surprisingly, no elevated-temperature tension stiffening model existed in the research literature, despite the established role that tension stiffening plays in the modeling of reinforced concrete members at ambient temperature. First, the energy-based stress-strain model of plain concrete developed by Bazant and Oh (1983) was extended to the elevated-temperature domain by developing an analytical formulation for the temperature-dependence of the fracture energy. Then, the elevated-temperature model was developed based on the modification of the proposed elevated-temperature tension softening model. The applicability and validation of the proposed tension stiffening model was then presented through the numerical analysis of several experimental tests of SCC floor systems exposed to fire. Using a sequentially-coupled thermal-structural analysis procedure, the thermal and structural response of two code compliant SCC floor systems were then examined under various fire types, including a family of traveling fires, two post-flashover fires, and a standard fire exposure. The results of the investigation showed that fire insulations derived from prescriptive approaches might not provide adequate safety under traveling fires. Failure times derived using a critical temperature criterion and a critical displacement criterion both showed that SCC floor systems perform poorly under traveling fires, which was not the case under the two post-flashover fires. The findings demonstrate a large vulnerability with prescriptive fire codes, and strengthens the case for the use of performance-based design in engineering practice.PHDCivil EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/168127/1/marjason_1.pd

Measuring ambivalence about government in the 2006 ANES Pilot Study.

Although scholars increasingly recognize that people often possess multiple and even conflicting attitudes about a given topic, our understanding of the nature, causes, and consequences of such attitudinal ambivalence is limited by a lack of consensus as to how the concept should be operationalized. In this paper, we examine three separate measures (one subjective, two operative) of ambivalence regarding the federal government in Washington that were asked in the 2006 ANES Pilot Study. Our findings indicate that while the operative measures are less susceptible to question-order and response-order effects, none of the three indicators fares particularly well in various other tests of construct validity