A Survey of Solver-Related Geometry and Meshing Issues

There is a concern in the computational fluid dynamics community that mesh generation is a significant bottleneck in the CFD workflow. This is one of several papers that will help set the stage for a moderated panel discussion addressing this issue. Although certain general "rules of thumb" and a priori mesh metrics can be used to ensure that some base level of mesh quality is achieved, inadequate consideration is often given to the type of solver or particular flow regime on which the mesh will be utilized. This paper explores how an analyst may want to think differently about a mesh based on considerations such as if a flow is compressible vs. incompressible or hypersonic vs. subsonic or if the solver is node-centered vs. cell-centered. This paper is a high-level investigation intended to provide general insight into how considering the nature of the solver or flow when performing mesh generation has the potential to increase the accuracy and/or robustness of the solution and drive the mesh generation process to a state where it is no longer a hindrance to the analysis process

Neighborhood revitalization through catalyst projects : capacity building and urban design in the West Philadelphia Landscape Project and the Bronx River Project

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2003.MIT Institute Archives copy: bound 29 x 23 cm.Includes bibliographical references (p. 125-129).Achieving meaningful neighborhood revitalization remains a perennial challenge for urban planners, as problems facing inner-city neighborhoods are complex and interconnected. Most recently, both the practice and literature of neighborhood revitalization emphasized a comprehensive approach. Within this context, the concepts of capacity building and catalyst projects are gaining momentum. This thesis explores the emergence of and points of synergy between these concepts through a review of the literature and analysis of two urban design and capacity building projects: the West Philadelphia Landscape Project in Philadelphia, Pennsylvania, and the Bronx River Project in New York City, New York. Underlying this inquiry is the fundamental question: do catalyst projects represent a departure from the status quo or a strategic repackaging of past practices? The primary questions addressed in this thesis are as follows: ** Is there a typology of catalytic effects within neighborhood revitalization projects? What types of circumstances foster the development of catalysts? ** What role does capacity building play in the development of catalytic effects in urban design projects? ** In what ways can project organizers become more deliberate about fostering catalytic effects? This study revealed three types of catalytic effects within the case studies: projects can act as models, foster spin-off projects, or provide an overarching framework to enable other projects to engage. Capacity building and catalytic effects are indeed interconnected and mutually supportive. There is no precise recipe for creating catalytic effects within projects, as they can be unexpected as well as planned. Furthermore, catalytic effects often depend on mediating circumstances, such as timing and organizational capacity, to foster their development. The act of forming partnerships, in particular, builds constituencies, expands funding opportunities, and allows for the development of spin-off projects. Most importantly, adopting a watershed framework as the lens through which to organize proved most significant as it encourages both institutional and neighborhood-level change. Watersheds transcend political, social, and institutional boundaries, and working in this realm necessitates the development and integration of grassroots and city-level actors. The extent to which catalyst projects lead to systems change remains to be seen, however they do present a powerful model for activating both institutional and neighborhood-level change through a single planning effort.by Desiree A. Sideroff.M.C.P

A Survey of Solver-Related Geometry and Meshing Issues

No abstract availabl

Psychosocial and treatment correlates of opiate free success in a clinical review of a naltrexone implant program

Background: There is on-going controversy in relation to the efficacy of naltrexone used for the treatment of heroin addiction, and the important covariates of that success. We were also interested to review our experience with two depot forms of implantable naltrexone. Methods: A retrospective review of patients' charts was undertaken, patients were recalled by telephone and by letter, and urine drug screen samples were collected. Opiate free success (OFS) was the parameter of interest. Three groups were defined. The first two were treated in the previous 12 months and comprised "implant" and "tablet" patients. A third group was "historical" comprising those treated orally in the preceding 12 months. Results: There were 102, 113 and 161 patients in each group respectively. Groups were matched for age, sex, and dose of heroin used, but not financial status or social support. The overall follow-up rate was 82%. The Kaplan Meier 12 month OFS were 82%, 58% and 52% respectively. 12 post-treatment variables were independently associated with treatment retention. In a Cox proportional hazard multivariate model social support, the number of detoxification episodes, post-treatment employment, the use of multiple implant episodes and spiritual belief were significantly related to OFS. Conclusion: Consistent with the voluminous international literature clinically useful retention rates can be achieved with naltrexone, which may be improved by implants and particularly serial implants, repeat detoxification, meticulous clinical follow-up, and social support. As depot formulations of naltrexone become increasingly available such results can guide their clinical deployment, improve treatment outcomes, and enlarge the policy options for an exciting non-addictive pharmacotherapy for opiate addiction

Detailed examinations of the human micro-environment by CFD

Computational fluid dynamics (CFD) has been used in this work as a tool to examine the flow, heat and mass transfer in the human micro-environment. First, guidelines were developed to demonstrate accurate CFD simulations of the personal micro-environment (PME). Canonical benchmark cases that represent two common ventilation systems, displacement and mixing, were used along with provided experimental data to verify and validate the CFD. For the benchmark cases, by following the grid resolution guidelines, it was discovered that a common RANS turbulence model, such as the standard k -ε, was capable of predicting the PME provided radiative heat transfer was included. Following the guidelines from the first objective, CFD was then used as a predictive tool to investigate the consequence of light activities on the PME. These light activities included transient breathing, head motion and the combination of the two. It was revealed for the proposed configuration, that while including light activities such as breathing and head motion had an influence on the PME they did not significantly affect personal exposure or a neighbors personal exposure

Motivational properties of septal stimulation as the US in classical conditioning of heart rate in rabbits

Examined heart-rate (HR) classical conditioning, shuttle-box training, and bar-press self-stimulation in male albino rabbits in 3 experiments as a function of 3 intensities of electrical stimulation of the septal region. In the HR classical conditioning experiment (n = 24), CRs failed to occur in a low-intensity group even though reliable UCRs were elicited. In 2 higher intensity groups HR CRs were decelerative. 12 Ss from Exp. 1 made approach responses to the lowest UCS intensity, but escape responses to higher intensities when tested in the shuttle box. In the self-stimulation experiment, 8 naive Ss bar pressed at all 3 intensities. At the 2 highest values, bar pressing was accompanied by attempted escape responses. It is concluded that HR classical conditioning to septal stimulation requires an aversive component to the UCS. (35 ref.

Cardiovascular classical conditioning in rabbits (Oryctolagus cuniculus) using appetitive or aversive hypothalamic stimulation as the US

Examined the bar-press self-stimulation, shuttle-box preference, and cardiovascular classical conditioning of 2 groups of 6 male rabbits as a function of electrical stimulation of the medial or lateral hypothalamus. Results show that Ss having access to lateral hypothalamic stimulation bar-pressed to receive stimulation and made approach responses in the shuttle box. Ss having access to medial hypothalamic stimulation did not bar-press and made escape responses in the shuttle box. The cardiovascular UCRs of all Ss consisted of a blood-pressure increase and heart-rate decrease; CRs consisted of heart-rate decreases. Thus, while medial and lateral hypothalamic stimulation had different motivational properties, both provided effective UCSs for eliciting similar heart-rate CRs. Data indicate that cardiovascular changes elicited by hypothalamic stimulation are not merely global adjustments to aversive stimulation. (18 ref.