24,648 research outputs found
Fiber-optic push-pull sensor systems
Fiber-optic push-pull sensors are those which exploit the intrinsically differential nature of an interferometer with concommitant benefits in common-mode rejection of undesired effects. Several fiber-optic accelerometer and hydrophone designs are described. Additionally, the recent development at the Naval Postgraduate School of a passive low-cost interferometric signal demodulator permits the development of economical fiber-optic sensor systems
Civil Society Legitimacy and Accountability: Issues and Challenges
University education rarely focuses its attention and imagination on teaching students how to turn a vision into reality; how to design, develop, and lead social change organizations. The author co-created the Social Entrepreneurship Collaboratory (SE Lab) at Stanford University and then Harvard University as a model educational program designed to achieve this goal. The SE Lab is a Silicon Valley influenced incubator where student teams create and develop innovative pilot projects for US and international social sector initiatives. The lab combines academic theory, frameworks, and traditional research with intensive field work, action research, peer support and learning, and participation of domain experts and social entrepreneurship practitioners. It also provides students an opportunity to collaborate on teams to develop business plans for their initiatives and to compete for awards and recognition in the marketplace of ideas. Students in the SE Lab have created innovative organizations serving many different social causes, including fighting AIDS in Africa, promoting literacy in Mexico, combating the conditions for terrorism using micro-finance in the Palestinian territories, and confronting gender inequality using social venture capital to empower women in Afghanistan
A High-Order Method for Stiff Boundary Value Problems with Turning Points
This paper describes some high-order collocation-like methods for the numerical solution of stiff boundary-value problems with turning points. The presentation concentrates on the implementation of these methods in conjunction with the implementation of the a priori mesh construction algorithm introduced by Kreiss, Nichols and Brown [SIAM J. Numer. Anal., 23 (1986), pp. 325–368] for such problems. Numerical examples are given showing the high accuracy which can be obtained in solving the boundary value problem for singularly perturbed ordinary differential equations with turning points
Civil Society Actors as Catalysts for Transnational Social Learning
This article explores the roles of transnational civil society organizations and networks in transnational social learning. It begins with an investigation into social learning within problem domains and into the ways in which such domain learning builds perspectives and capacities for effective action among domain organizations and institutions. It suggests that domain learning involves problem definition, direction setting, implementation of collective action, and performance monitoring. Transnational civil society actors appear to take five roles in domain learning: (1) identifying issues, (2) facilitating voice of marginalized stakeholders, (3) amplifying the importance of issues, (4) building bridges among diverse stakeholders, and (5) monitoring and assessing solutions. The paper then explores the circumstances in which transnational civil society actors can be expected to make special contributions in important problem domains in the future.This publication is Hauser Center Working Paper No. 28. The Hauser Center Working Paper Series was launched during the summer of 2000. The Series enables the Hauser Center to share with a broad audience important works-in-progress written by Hauser Center scholars and researchers
Understanding voluntary organizations : guidelines for donors
Voluntary development organizations have demonstrated substantial comparatiave advantage in developing countries - especially in their ability to innovate, adapt to local conditions, and reach and work with poor and difficult to reach populations. These capabilities are a function of their values, special skills, small size, limited resources, flexibility, and freedom from political constraints. Their weaknesses are a function of many of the same characteristics - particularly their value commitments, small size, independence, and lack of administrative rigidity. The authors explain that the strongest Voluntary Organizations (VOs) and People's Organizations (POs) respond to more than financial incentives. Their strength lies in the fact that they are not the same as government organizations or businesses. At the same time, they are not immune to financial incentives, which if wrongly applied can destroy the voluntarism of all but the most strongly aware of VOs and POs.Environmental Economics&Policies,Early Child and Children's Health,Health Economics&Finance,Health Monitoring&Evaluation,Poverty Assessment
Harmonizing the paradigm with the data in stable coronary artery disease: A review and viewpoint
Resonant Acoustic Determination of Complex Elastic Moduli
A simple, inexpensive, yet accurate method for measuring the dynamic complex modulus of elasticity is described. Using a 'free-free' bar selectively excited in three independent vibrational modes, the shear modulus is obtained by measuring the frequency of the torsional resonant mode and the Young's modulus is determined from measurement of either the longitudinal or flexural mode. The damping properties are obtained by measuring the quality factor (Q) for each mode. The Q is inversely proportional to the loss tangent. The viscoelastic behavior of the sample can be obtained by tracking a particular resonant mode (and thus a particular modulus) using a phase locked loop (PLL) and by changing the temperature of the sample. The change in the damping properties is obtained by measuring the in-phase amplitude of the PLL which is proportional to the Q of the material. The real and imaginary parts or the complex modulus can be obtained continuously as a function of parameters such as temperature, pressure, or humidity. For homogeneous and isotropic samples only two independent moduli are needed in order to characterize the complete set of elastic constants, thus, values can be obtained for the dynamic Poisson's ratio, bulk modulus, Lame constants, etc
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A Two-Dimensional Mesh Refinement Method for Problems with One-Dimensional Singularities
This paper introduces a method for resolving internal layers that can occur in the solutions of time-dependent differential equations in two space dimensions. Singular features in these solutions that are essentially one-dimensional in nature but are not oriented with the computational mesh are resolved using one-dimensional mesh refinement techniques with a procedure that is similar to an ADI method. A careful interpolation procedure assures that the resolution obtained in each ADI step is not lost in the succeeding ADI step
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