The shuttle main engine: A first look

Anyone entering the Space Shuttle Main Engine (SSME) team attends a two week course to become familiar with the design and workings of the engine. This course provides intensive coverage of the individual hardware items and their functions. Some individuals, particularly those involved with software maintenance and development, have felt overwhelmed by this volume of material and their lack of a logical framework in which to place it. To provide this logical framework, it was decided that a brief self-taught introduction to the overall operation of the SSME should be designed. To aid the people or new team members with an interest in the software, this new course should also explain the structure and functioning of the controller and its software. This paper presents a description of this presentation

Service user and carer involvement in mental health education: a grounded theory investigation into its impact on (trainee) clinical psychologists' learning

Service user and carer involvement has become a priority in the education of mental health professionals. While preliminary evidence suggests that service user and carer involvement is perceived positively by mental health students, there is a paucity of research investigating impacts relating to changes in learners’ knowledge, skills, attitudes or behaviour. The present qualitative study sought to investigate what, and how, (trainee) clinical psychologists learn as a result of service user and carer involvement in their training. Overall, 12 (trainee) clinical psychologists were interviewed and grounded theory methodology was used to analyse the data. Findings indicated that (trainee) clinical psychologists learned from service user and carer involvement in a variety of ways and a preliminary model was proposed, encompassing four main categories: 'mechanisms of learning', 'relational and contextual factors facilitating learning', 'relational and contextual factors hindering learning' and 'impact'. The findings are discussed in relation to extant empirical research, taking into account theoretical considerations. Recommendations for educators in clinical psychology training programmes are provided alongside suggestions for a future research agenda. A methodological critique of the study is offered

Valuing information from mesoscale forecasts

The development of meso-gamma scale numerical weather prediction (NWP) models requires a substantial investment in research, development and computational resources. Traditional objective verification of deterministic model output fails to demonstrate the added value of high-resolution forecasts made by such models. It is generally accepted from subjective verification that these models nevertheless have a predictive potential for small-scale weather phenomena and extreme weather events. This has prompted an extensive body of research into new verification techniques and scores aimed at developing mesoscale performance measures that objectively demonstrate the return on investment in meso-gamma NWP. In this article it is argued that the evaluation of the information in mesoscale forecasts should be essentially connected to the method that is used to extract this information from the direct model output (DMO). This could be an evaluation by a forecaster, but, given the probabilistic nature of small-scale weather, is more likely a form of statistical post-processing. Using model output statistics (MOS) and traditional verification scores, the potential of this approach is demonstrated both on an educational abstraction and a real world example. The MOS approach for this article incorporates concepts from fuzzy verification. This MOS approach objectively weighs different forecast quality measures and as such it is an essential extension of fuzzy methods

Evaluation of the efficiency and fault density of software generated by code generators

Flight computers and flight software are used for GN&C (guidance, navigation, and control), engine controllers, and avionics during missions. The software development requires the generation of a considerable amount of code. The engineers who generate the code make mistakes and the generation of a large body of code with high reliability requires considerable time. Computer-aided software engineering (CASE) tools are available which generates code automatically with inputs through graphical interfaces. These tools are referred to as code generators. In theory, code generators could write highly reliable code quickly and inexpensively. The various code generators offer different levels of reliability checking. Some check only the finished product while some allow checking of individual modules and combined sets of modules as well. Considering NASA's requirement for reliability, an in house manually generated code is needed. Furthermore, automatically generated code is reputed to be as efficient as the best manually generated code when executed. In house verification is warranted

Scattering and the Point Spread Function of the New Generation Space Telescope

Preliminary design work on the New Generation Space Telescope (NGST) is currently under way. This telescope is envisioned as a lightweight, deployable Cassegrain reflector with an aperture of 8 meters, and an effective focal length of 80 meters. It is to be folded into a small-diameter package for launch by an Atlas booster, and unfolded in orbit. The primary is to consist of an octagon with a hole at the center, and with eight segments arranged in a flower petal configuration about the octagon. The comers of the petal-shaped segments are to be trimmed so that the package will fit atop the Atlas booster. This mirror, along with its secondary will focus the light from a point source into an image which is spread from a point by diffraction effects, figure errors, and scattering of light from the surface. The distribution of light in the image of a point source is called a point spread function (PSF). The obstruction of the incident light by the secondary mirror and its support structure, the trimmed corners of the petals, and the grooves between the segments all cause the diffraction pattern characterizing an ideal point spread function to be changed, with the trimmed comers causing the rings of the Airy pattern to become broken up, and the linear grooves causing diffraction spikes running radially away from the central spot, or Airy disk. Any figure errors the mirror segments may have, or any errors in aligning the petals with the central octagon will also spread the light out from the ideal point spread function. A point spread function for a mirror the size of the NGST and having an incident wavelength of 900 nm is considered. Most of the light is confined in a circle with a diameter of 0.05 arc seconds. The ring pattern ranges in intensity from 10(exp -2) near the center to 10(exp -6) near the edge of the plotted field, and can be clearly discerned in a log plot of the intensity. The total fraction of the light scattered from this point spread function is called the total integrated scattering (TIS), and the fraction remaining is called the Strehl ratio. The angular distribution of the scattered light is called the angle resolved scattering (ARS), and it shows a strong spike centered on a scattering angle of zero, and a broad , less intense distribution at larger angles. It is this scattered light, and its effect on the point spread function which is the focus of this study

Learning from service user and carer involvement in clinical psychology training

Purpose – The purpose of this paper is to build a theoretical model of how and what clinical psychologists learn from service user and carer involvement in their training. Design/methodology/approach – A qualitative research design was adopted, and verbatim transcripts of semi-structured interviews conducted with 12 clinical psychologists were analysed using grounded theory methodology. Findings – Findings indicated that clinical psychologists learned from service user and carer involvement in a variety of ways and a preliminary model was proposed, encompassing four main categories: “mechanisms of learning”, “relational and contextual factors facilitating learning”, “relational and contextual factors hindering learning” and “impact”. Research limitations/implications – Further research is required to establish to what extent the current findings may be transferrable to learning from service user and carer involvement in the context of educating professionals from other disciplines. Additionally, participants had limited experiences of carer involvement, and more research in this area specifically would be useful. Practical implications – This study advocates for service user and carer involvement in clinical psychology training, and specific recommendations are discussed, including service user perspectives. Originality/value – Service user and carer involvement has become mandatory in Health Care Professional Council-approved training programmes for mental health professionals, yet if and how learning occurs is poorly understood in this context. This study makes an important contribution in evaluating outcomes of service user and carer involvement in clinical psychology training by advancing theoretical understanding of the learning processes involved. The authors are unaware of similar work

De geboorte van het Hollandse bouwblok

Dutch housing culture has its origins in the urban terraced houses in which people lived and worked for centuries, in all kinds of configurations. 1 The individual dwelling remained the determining unit of urban development until industrialization took off in the nineteenth century. However, even in the seventeenth century, people were thinking and designing on a larger scale; of this, the urban extension of the Amsterdam canal area is the best-known exponent. But while this extension plan concerned an entire district, in the end it was yet again the terraced house, in this case the chic canal-side house, that was the development unit. As a result, the character of the city block remained secondary, with the urban design dependant on individual owners.2 Much less known but all the more interesting are a number of projects from the same period that were actually based on the entire city block as a development and design unit. In quick succession, various architects in different cities took on the experiment to create designs for city blocks that combined living and working for a specific target group, namely weavers and their families. This article will compare three of these weavers’ blocks and join the architects in their search for the added value of the city block as a design unit. What advantages did they see? What design choices did they make on the basis of perceived advantages? Did the combination of living and working in these artisan dwellings influence the design, and which criteria were decisive? What could the designers refer to in their façade designs given the fact that the entire city block was the architectural unit? And finally, with regard to flexibility: How did they guarantee that they would be able to find tenants, should the weavers stay away? These are questions that, if you look at current discussions about urban living and working blocks, have lost none of their topicality.De Nederlandse wooncultuur heeft haar oorsprong in het stedelijke rijtjeshuis, waarin eeuwenlang werd gewoond én gewerkt, in allerlei combinaties.1 Het individuele huis zal tot de industrialisatie in de negentiende eeuw bouwsteen van de stadsontwikkeling blijven. Toch komt er in de zeventiende eeuw al een eerste ontwikkeling op gang waarin grootschaliger wordt gedacht en ontworpen, met de stadsuitleg van de Amsterdamse grachten als bekendste exponent. Maar terwijl dit plan een hele wijk betrof, is uiteindelijk toch weer het rijtjeshuis, in dit geval het chique grachtenpand, de ontwikkeleenheid. Hierdoor blijft het bouwblok additief van karakter en de stedenbouw afhankelijk van individuele eigenaars.2 Veel minder bekend maar des te interessanter is een aantal projecten uit dezelfde tijd, dat uitgaat van het hele bouwblok als ontwikkel- en ontwerpeenheid. Kort na elkaar wagen in diverse steden verschillende architecten zich aan dit experiment, met ontwerpen voor bouwblokken die wonen en werken combineren voor een specifieke doelgroep, namelijk wevers en hun families. Dit artikel zal drie ‘weversblokken’ met elkaar vergelijken, en de architecten volgen in hun zoektocht naar de meerwaarde van het stadsblok als ontwerpeenheid. Welke voordelen zagen ze, en welke ontwerpkeuzes maakten ze op basis hiervan? Was de combinatie van wonen en werken in deze ambachtshuizen van invloed op het ontwerp, en welke criteria waren hierbij beslissend? Waar konden de ontwerpers naar refereren in de gevelontwerpen, op het moment dat een heel bouwblok de architectonische eenheid was? En tot slot de kwestie van flexibiliteit: hoe garandeerden ze de mogelijkheden voor verhuur, mochten de wevers wegblijven? Het zijn vragen die, als je kijkt naar de discussies over het woon-werkblok, nog niets van hun actualiteit verloren hebben