Thermal and convection analyses of the dendrite remelting rocket experiment; Experiment 74-21 in the space processing rocket program

The Dendrite Remelting Rocket Experiment was performed aboard a Black Brant VC Sounding Rocket during a period which gravity levels of approximately 0.00001 g prevailed. The experiment consisted of cooling an aqueous ammonium chloride solution in a manner such that crystallization of ammonium chloride crystals proceeded throughout a three minute period of zero-g. The crystallization process during flight was recorded on 35 mm panatomic-x film. A number of ground crystallizations were similarly recorded for comparison purposes. The convective and thermal conditions in aqueous and metallic liquid systems were assessed under conditions of the flight experiment to help establish the relevance of the rocket experiment to metals casting phenomena. The results indicate that aqueous or metallic convective velocities in the Dendrite Remelting Rocket Experiment cell are of insignificant magnitudes at the 0.0001 to 0.00001 g levels of the experiment. The crystallization phenomena observed in the Rocket Experiment, therefore, may be indicative of how metals will solidify in low-g

Development of the general interpolants method for the CYBER 200 series of supercomputers

The General Interpolants Method (GIM) is a 3-D, time-dependent, hybrid procedure for generating numerical analogs of the conservation laws. This study is directed toward the development and application of the GIM computer code for fluid dynamic research applications as implemented for the Cyber 200 series of supercomputers. An elliptic and quasi-parabolic version of the GIM code are discussed. Turbulence models, algebraic and differential equations, were added to the basic viscous code. An equilibrium reacting chemistry model and an implicit finite difference scheme are also included

Adaptive finite element methods for two-dimensional problems in computational fracture mechanics

Some recent results obtained using solution-adaptive finite element methods in two-dimensional problems in linear elastic fracture mechanics are presented. The focus is on the basic issue of adaptive finite element methods for validating the new methodology by computing demonstration problems and comparing the stress intensity factors to analytical results

Manufacturing in space: Fluid dynamics numerical analysis

Numerical computations were performed for natural convection in circular enclosures under various conditions of acceleration. It was found that subcritical acceleration vectors applied in the direction of the temperature gradient will lead to an eventual state of rest regardless of the initial state of motion. Supercritical acceleration vectors will lead to the same steady state condition of motion regardless of the initial state of motion. Convection velocities were computed for acceleration vectors at various angles of the initial temperature gradient. The results for Rayleigh numbers of 1000 or less were found to closely follow Weinbaum's first order theory. Higher Rayleigh number results were shown to depart significantly from the first order theory. Supercritical behavior was confirmed for Rayleigh numbers greater than the known supercritical value of 9216. Response times were determined to provide an indication of the time required to change states of motion for the various cases considered

Manufacturing in space: Fluid dynamics numerical analysis

Natural convection in a spherical container with cooling at the center was numerically simulated using the Lockheed-developed General Interpolants Method (GIM) numerical fluid dynamic computer program. The numerical analysis was simplified by assuming axisymmetric flow in the spherical container, with the symmetry axis being a sphere diagonal parallel to the gravity vector. This axisymmetric spherical geometry was intended as an idealization of the proposed Lal/Kroes growing experiments to be performed on board Spacelab. Results were obtained for a range of Rayleigh numbers from 25 to 10,000. For a temperature difference of 10 C from the cooling sting at the center to the container surface, and a gravitional loading of 0.000001 g a computed maximum fluid velocity of about 2.4 x 0.00001 cm/sec was reached after about 250 sec. The computed velocities were found to be approximately proportional to the Rayleigh number over the range of Rayleigh numbers investigated

Working with and for social enterprises: the role of the volunteer ethnographer

Purpose – This paper considers the specific opportunities and challenges of engaging in ethnographic research with organisations in which the researcher participates as a volunteer ethnographer. Design/methodology/approach – The findings in this paper are based on four years of ethnographic research within a social enterprise. Findings – This paper finds that there are significant benefits of the role of the volunteer ethnographer and suggests ways to address some of the challenges. Research limitations/implications – As the field of social enterprise and ethnography grows and researchers engage with methodological discussions about participant observation, the authors suggest that attention should also be paid to the specifics of the role of the volunteer ethnographer. Originality/value – There is growing interest in the use of ethnography in social enterprises. This paper offers unique insight into how this methodology has been applied in the context of self-reliant groups and the importance of the engaging with discussion about the specific role of the volunteer ethnographer

Analytical support for SPAR experiment 76-36

The apparatus, materials, and procedures used in an analysis of thermal, convective, and rotational fluid flow for a second series of rocket experiments of dendrite growth are described. A constitutive supercooling criterion was calculated from the thermal data. A convection analysis was made of the various cases to ensure that convective velocities will not exceed about .01 cm/sec in the low-g tests. Damping times for fluid flow generated by rocket spin-up and spin-down were also determined, so that the conditions for this experiment are generally the same as those for the SPAR experiment 74-21 study of ammonium chloride low-g crystallizations

Achieving provider engagement: providers' perceptions of implementing and delivering integrated care

The literature on integrated care is limited with respect to practical learning and experience. Although some attention has been paid to organizational processes and structures, not enough is paid to people, relationships, and the importance of these in bringing about integration. Little is known, for example, about provider engagement in the organizational change process, how to obtain and maintain it, and how it is demonstrated in the delivery of integrated care. Based on qualitative data from the evaluation of a large-scale integrated care initiative in London, United Kingdom, we explored the role of provider engagement in effective integration of services. Using thematic analysis, we identified an evolving engagement narrative with three distinct phases: enthusiasm, antipathy, and ambivalence, and argue that health care managers need to be aware of the impact of professional engagement to succeed in advancing the integrated care agenda

Labour market experiences of young UK Bangladeshi men: Identity, inclusion and exclusion in inner-city London

Detailed qualitative data are used to explore the processes perpetuatinglabour market disadvantage among young UK-Bangladeshi men living in central London. Strong forces of inclusion within the Bangladeshi community are found to interact with forces of exclusion from ‘mainstream’ society to constrain aspirations and limit opportunities. Though diverse forms of young Bangladeshi masculinity are found, a common pattern is heavy dependency on intra-ethnic networks. Negative experiences of and isolation from ‘mainstream’ society further reinforce reliance on ‘our own people’. However, acute ambivalence towards belonging to a dense Bangladeshi community exists, exemplified in the widespread denigration of the restaurant trade. Many respondents express the desire to ‘break out’ and access new experiences. The findings support current policy emphasis on ‘connecting people to work’ but highlight the more fundamental need to connect people across ethnic boundaries. The paper urges researchers to ‘unpack’ ethnicity to consider carefully what ethnic identity implies in terms of access to resources and opportunities for different individuals in different contexts in order better to understand the diversity of labour market outcomes and the persistence of disadvantage