Evaluation of potassium titanate as a component of alkaline fuel cell matrices

Various forms of potassium titanate were found to have almost complete resistance to chemical attack in 45 wt % KOH at 150 C (423 K) for up to 9600 hours. Electron microscopy and X-ray diffraction disclosed important differences with respect to fibricity and stability. The octatitanate appeared to possess the best combination of properties. It was concluded that potassium titanate could be produced in a more asbestos-like form. Fiber dispersion is important in matrix manufacture

Tight bounds for break minimization

We consider round-robin sports tournaments with n teams and n − 1 rounds. We construct an infinite family of opponent schedules for which every home-away assignment induces at least 1/4 n(n−2) breaks. This construction establishes a matching lower bound for a corresponding upper bound from the literature

Effects of temperature and electrolyte concentration on performance of a fuel cell of the Bacon type

Effects of temperature and electrolyte concentration on performance of fuel cel

Mobilizing Public Will For Social Change

Examines the theory and strategies of "public will" campaigns and offers tangible criteria for their evaluation. It provides a rich inventory of strategies for use in mobilizing the public will through an integration of models of agenda building, social problem construction, issues management, social movements, media advocacy, and social capital. In addition, the paper provides cases and examples of public will campaigns directed at various social problems, along with criteria for evaluating these campaigns at various stages of a social problem's life cycle

Infinite families of superintegrable systems separable in subgroup coordinates

A method is presented that makes it possible to embed a subgroup separable superintegrable system into an infinite family of systems that are integrable and exactly-solvable. It is shown that in two dimensional Euclidean or pseudo-Euclidean spaces the method also preserves superintegrability. Two infinite families of classical and quantum superintegrable systems are obtained in two-dimensional pseudo-Euclidean space whose classical trajectories and quantum eigenfunctions are investigated. In particular, the wave-functions are expressed in terms of Laguerre and generalized Bessel polynomials.Comment: 19 pages, 6 figure

Maxwell's theory on a post-Riemannian spacetime and the equivalence principle

The form of Maxwell's theory is well known in the framework of general relativity, a fact that is related to the applicability of the principle of equivalence to electromagnetic phenomena. We pose the question whether this form changes if torsion and/or nonmetricity fields are allowed for in spacetime. Starting from the conservation laws of electric charge and magnetic flux, we recognize that the Maxwell equations themselves remain the same, but the constitutive law must depend on the metric and, additionally, may depend on quantities related to torsion and/or nonmetricity. We illustrate our results by putting an electric charge on top of a spherically symmetric exact solution of the metric-affine gauge theory of gravity (comprising torsion and nonmetricity). All this is compared to the recent results of Vandyck.Comment: 9 pages, REVTeX, no figures; minor changes, version to be published in Class. Quantum Gra

A General Class of Metamaterial Transformation Slabs

In this paper, we apply transformation-based optics to the derivation of a general class of transparent metamaterial slabs. By means of analytical and numerical full-wave studies, we explore their image displacement/formation capabilities, and establish intriguing connections with configurations already known in the literature. Starting from these revisitations, we develop a number of nontrivial extensions, and illustrate their possible applications to the design of perfect radomes, anti-cloaking devices, and focusing devices based on double-positive (possibly nonmagnetic) media. These designs show that such anomalous features may be achieved without necessarily relying on negative-index or strongly resonant metamaterials, suggesting more practical venues for the realization of these devices.Comment: 25 pages, 13 figures; minor changes in the tex

Participatory inclusion evaluation: a flexible approach to building the evidence base on the impact of community-based rehabilitation and inclusive development programmes

In response to the variability, complexity, and cross-sectoral nature of community-based rehabilitation (CBR) programmes and the lack of a structured approach to impact evaluations, an innovative model and set of tools, called the participatory inclusion evaluation (PIE) approach, has been developed. This is conceptualised in an evaluation framework, influenced by diverse evaluation theories and methods used in mainstream international development. Each has its own merits and shortcomings, so we have developed a hybrid to ensure a pragmatic and flexible mixed methods approach. We discuss the theoretical choices made in the evolution of PIE. PIE involves the participation of three types of stakeholders: people with disabilities, the CBR core team, and the network of strategic partners. PIE assesses the impact and the what, how and why of CBR programmes, privileging people with disabilities’ perspectives. In synchrony with the UN Convention on the Rights of Persons with Disabilities (CRPD) principles and the World Health Organisation (WHO) CBR guidelines, impact is defined as changes in inclusion, empowerment, and living conditions. PIE was developed using a participatory process, piloted in Uganda and Malawi. It provides a flexible outcome and impact evaluation methodology for CBR, using a mixture of quantitative and qualitative data, using an inclusive and participatory approach

Infrastructure for washable computing

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 1999.Includes bibliographical references (leaves 73-74).Wash-and-wear multilayer electronic circuitry can be constructed on fabric substrates, using conductive textiles and suitably packaged components. Fabrics are perhaps the first composite materials engineered by humanity; their evolution led to the development of the Jacquard loom, which itself led to the development of the modern computer. The development of fabric circuitry is a compelling closure of the cycle that points to a new class of textiles which interact with their users and their environments, while retaining the properties that made them the first ubiquitous "smart material". Fabrics are in several respects superior to existing flexible substrates in terms of their durability, conformability, and breathability. The present work adopts a modular approach to circuit fabrication, from which follow circuit design techniques and component packages optimized for use in fabric-based circuitry, flexible all-fabric interconnects, and multilayer circuits. While maintaining close compatibility with existing components, tools, and techniques, the present work demonstrates all steps of a process to create multilayer printed circuits on fabric substrates using conductive textiles.by E. Rehmi Post.S.M