716 research outputs found
Design study for a magnetically supported reaction wheel
Results are described of a study program in which the characteristics of a magnetically supported reaction wheel are defined. Tradeoff analyses are presented for the principal components, which are then combined in several reaction wheel design concepts. A preliminary layout of the preferred configuration is presented along with calculated design and performance parameters. Recommendations are made for a prototype development program
Magnetically suspended reaction wheel assembly
The magnetically suspended reaction wheel assembly (MSRWA) is the product of a development effort funded by the Air Force Materials Laboratory (AFML) at Wright Patterson AFB. The specific objective of the project was to establish the manufacturing processes for samarium cobalt magnets and demonstrate their use in a space application. The development was successful on both counts. The application portion of the program, which involves the magnetically suspended reaction wheel assembly, is emphasized. The requirements for the reaction wheel were based on the bias wheel requirements of the DSP satellite. The tasks included the design, fabrication, and test of the unit to the DSP program qualification requirements
Book Reviews
TO SECURE THESE RIGHTS
The Report of the President\u27s Committee on Civil Rights with An Introduction
by Charles S. Wilson, Committee Chairman.
New York: Simon and Schuster, 1947. Pp. xii, 178. 4.50.
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A NATIONAL POLICY FOR THE OIL INDUSTRY
By Eugene V. Rostow
New Haven: Yale University Press, 1948. Pp. XVI, 173. 3.00.
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AMERICA\u27S ECONOMIC SUPREMACY
By Brooks Adams
New York: Harper & Brothers, Inc., 1947. Pp. 194. $2.50
How Are the Interests of Incapacitated Research Participants Protected through Legislation? An Italian Study on Legal Agency for Dementia Patients
Patients with dementia may have limited capacity to give informed consent to participate in clinical research. One possible way to safeguard the patients' interests in research is the involvement of a proxy in the recruitment process. In Italy, the system of proxy is determined by the courts. In this study we evaluate the timing for appointment of a legal proxy in Italy and identify predictive variables of appointment.Subjects were recruited among the outpatients seeking medical advice for cognitive complaints at the Centre for Research and Treatment of Cognitive Dysfunctions, University of Milan, "Luigi Sacco" Hospital. The Centre was participating to the AdCare Study, a no-profit randomised clinical trial coordinated by the Italian National Institute of Health. The requirement that informed consent be given by a legal representative dramatically slowed down the recruitment process in AdCare, which was prematurely interrupted. The Centre for Research and Treatment of Cognitive Dysfunctions collected data on the timing required to appoint the legal representatives. Patients diagnosed with dementia and their caregivers were provided information on the Italian law on legal agency (law 6/2004). At each scheduled check-up the caregiver was asked whether she/he had applied to appoint a legal proxy for the patient and the time interval between the presentation of the law, the registration of the application at the law court chancellery and the sentence of appointment was registered. The study involved 169 demented patients. Seventy-eight patients (46.2%) applied to appoint a legal proxy. These subjects were usually younger, had been suffering from dementia for a longer time, had less than two children and made more use of memantine. The mean interval time between the presentation of the law and the patients' application to the law court chancellery was two months. The mean interval time between the patient's application to the law court chancellery and the sentence of appointment was four months.In Italy the requirement that legal representatives be appointed by the courts slows down subjects' participation in research. Other procedures for legal agency of the incapacitated patients may be adopted, taking as examples other EU countries' systems
Sonic boom and drag evaluation of supersonic jet concepts
This paper evaluates three different class supersonic airliners (Concorde, Cranfield E-5, and NASA QueSST X-plane) in a multidisciplinary design analysis optimization (MDAO) environment in terms of their sonic boom intensities and aerodynamic performance. The aerodynamic analysis and sonic boom prediction methods are key to this research. The panel method PANAIR is integrated to perform automated aerodynamic analysis. The drag coefficient is corrected by the Harris wave drag formula and form factor method. For sonic boom prediction, the near-field pressure is predicted through the Whitham F-function method. The F-function is decomposed to the F-function due to volume and the F-function due to lift to see their individual effect on sonic boom. The near-field signature propagates in a stratified windy atmosphere using the waveform parameter method. The aerodynamic results are compared with experimental data and the sonic boom prediction results are validated by the NASA PCBoom program. Through the evaluation, we find a direct link between the wave drag and the first derivative of the volume distribution. The sonic boom intensity is influenced by the lift distribution and the volume change rate. The study helps to study the feasibility of low-boom and low-drag supersonic airliners
Fungal Origins of the Bicyclo[2.2.2]diazaoctane Ring System of Prenylated Indole Alkaloids
Over eight different families of natural products, consisting of nearly seventy secondary metabolites, which contain the bicyclo[2.2.2]diazaoctane ring system, have been isolated from various Aspergillus, Penicillium, and Malbranchea species. Since 1968, these secondary metabolites have been the focus of numerous biogenetic, synthetic, taxonomic, and biological studies, and, as such, have made a lasting impact across multiple scientific disciplines. This review covers the isolation, biosynthesis, and biological activity of these unique secondary metabolites containing the bridging bicyclo[2.2.2]diazaoctane ring system. Furthermore, the diverse fungal origin of these natural products is closely examined and, in many cases, updated to reflect the currently accepted fungal taxonomy
Collaboration and knowledge exchange between scholars in Britain and the empire, 1830–1914
In recent years there has been a growing interest among historians in the British Empire as a space of knowledge production and circulation. Much of this work assumes that scholarly cooperation and collaboration between individuals and institutions within the Empire had the effect (and often also the aim) of strengthening both imperial ties and the idea of empire. This chapter argues, however, that many examples of scholarly travel, exchange, and collaboration were undertaken with very different goals in mind. In particular, it highlights the continuing importance of an ideal of scientific internationalism, which stressed the benefits of scholarship for the whole of humanity and prioritized the needs and goals of individual academic and scientific disciplines. As the chapter shows, some scholars even went on to develop nuanced critiques of the imperial project while using the very structures of empire to further their own individual, disciplinary and institutional goals
Método para a estimativa da cobertura do solo e da altura do dossel de algumas culturas de verão
How Biology Became Social and What It Means for Social Theory
In this paper I first offer a systematic outline of a series of conceptual novelties in
the life-sciences that have favoured, over the last three decades, the emergence of a
more social view of biology. I focus in particular on three areas of investigation: (1)
technical changes in evolutionary literature that have provoked a rethinking of the
possibility of altruism, morality and prosocial behaviours in evolution; (2) changes
in neuroscience, from an understanding of the brain as an isolated data processor to
the ultrasocial and multiply connected social brain of contemporary neuroscience;
and (3) changes in molecular biology, from the view of the gene as an autonomous
master of development to the ‘reactive genome’ of the new emerging field of
molecular epigenetics. In the second section I reflect on the possible implications for
the social sciences of this novel biosocial terrain and argue that the postgenomic
language of extended epigenetic inheritance and blurring of the nature/nurture
boundaries will be as provocative for neo-Darwinism as it is for the social sciences
as we have known them. Signs of a new biosocial language are emerging in several
social-science disciplines and this may represent an exciting theoretical novelty for
twenty-first social theory
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