363 research outputs found
Manned Orbital Transfer Vehicle (MOTV). Volume 3: Program requirements documents
The requirements for geosynchronous orbit capability using the manned orbit transfer vehicle (MOTV) are defined. The program requirements, the mission requirements, and the system and subsystem requirements for the MOTV are discussed. The mission requirements include a geosynchronous Earth orbit vehicle for the construction, servicing, repair and operation of communications, solar power, and Earth observation satellites
Manned Orbital Transfer Vehicle (MOTV). Volume 2: Mission handbook
The use of the manned orbit transfer vehicle (MOTV) for support of future space missions is defined. Some 20 generic missions are defined each representative of the types of missions expected to be flown in the future. These include the service and update of communications satellites, emergency repair of surveillance satellites, and passenger transport of a six man crew rotation/resupply service to a deep space command post. The propulsive and functional capabilities required of the MOTV to support a particular mission are described and data to enable the user to determine the number of STS flights needed to support the mission, mission peculiar equipment requirements, parametrics on mission phasing and requirements, ground and flight support requirements, recovery considerations, and IVA/EVA trade analysis are presented
Manned Orbital Transfer Vehicle (MOTV). Volume 4: Supporting analysis
Generic missions were defined to enable potential users to determine the parameters for suggested user projects. Mission modes were identified for providing operation, interfaces, performance, and cost data for studying payloads. Safety requirements for emergencies during various phases of the mission are considered with emphasis on radiation hazards
Manned Orbital Transfer Vehicle (MOTV). Volume 6: Five year program plan
The five year program plan for the manned orbit transfer vehicle (MOTV) is presented. The planning, schedules, cost estimates, and supporting data (objectives, constraints, assumptions, etc.) associated with the development of the MOTV are discussed. The plan, in addition to the above material, identifies the supporting research and technology required to resolve issues critical to MOTV development
Manned geosynchronous mission requirements and systems analysis study. Volume 1: Executive summary
The crew capsule of the MOTV was studied with emphasis on crew accommodations, crew capsule functional requirements, subsystem interface definition between crew module and propulsion module, and man rating requirements. Competing mission modes were studied covering a wide range of propulsion concepts. These included one stage, one and one half stage, and two stage concepts using either the standard STS or an augmented STS. Several deorbit concepts were considered, including all propulsive modes, direct re-entry, and aeromaneuvering skip in skip out in the upper reaches of Earth's atmosphere. A five year plan covering costs, schedules, and critical technology issues is discussed
Hyperbolic outer billiards : a first example
We present the first example of a hyperbolic outer billiard. More precisely
we construct a one parameter family of examples which in some sense correspond
to the Bunimovich billiards.Comment: 11 pages, 8 figures, to appear in Nonlinearit
Topological signature of deterministic chaos in short nonstationary signals from an optical parametric oscillator
Although deterministic chaos has been predicted to occur in the triply
resonant optical parametric oscillator (TROPO) fifteen years ago, experimental
evidence of chaotic behavior in this system has been lacking so far, in marked
contrast with most nonlinear systems, where chaos has been actively tracked and
found. This situation is probably linked to the high sensitivity of the TROPO
to perturbations, which adversely affects stationary operation at high power.
We report the experimental observation in this system of a burst of irregular
behavior of duration 80 microseconds. Although the system is highly
nonstationary over this time interval, a topological analysis allows us to
extract a clearcut signature of deterministic chaos from a time series segment
of only 9 base cycles (3 microseconds). This result suggests that
nonstationarity is not necessarily an obstacle to the characterization of
chaos
Piecewise Linear Models for the Quasiperiodic Transition to Chaos
We formulate and study analytically and computationally two families of
piecewise linear degree one circle maps. These families offer the rare
advantage of being non-trivial but essentially solvable models for the
phenomenon of mode-locking and the quasi-periodic transition to chaos. For
instance, for these families, we obtain complete solutions to several questions
still largely unanswered for families of smooth circle maps. Our main results
describe (1) the sets of maps in these families having some prescribed rotation
interval; (2) the boundaries between zero and positive topological entropy and
between zero length and non-zero length rotation interval; and (3) the
structure and bifurcations of the attractors in one of these families. We
discuss the interpretation of these maps as low-order spline approximations to
the classic ``sine-circle'' map and examine more generally the implications of
our results for the case of smooth circle maps. We also mention a possible
connection to recent experiments on models of a driven Josephson junction.Comment: 75 pages, plain TeX, 47 figures (available on request
Polymorphic dinucleotide microsatellite loci in the sandfly Lutzomyia longipalpis (Diptera: Phlebotominae)
A scoping review of outdoor food marketing: exposure, power and impacts on eating behaviour and health
Background: There is convincing evidence that unhealthy food marketing is extensive on television and in digital media, uses powerful persuasive techniques, and impacts dietary choices and consumption, particularly in children. It is less clear whether this is also the case for outdoor food marketing. This review (i) identifies common criteria used to define outdoor food marketing, (ii) summarises research methodologies used, (iii) identifies available evidence on the exposure, power (i.e. persuasive creative strategies within marketing) and impact of outdoor food marketing on behaviour and health and (iv) identifies knowledge gaps and directions for future research. Methods: A systematic search was conducted of Medline (Ovid), Scopus, Science Direct, Proquest, PsycINFO, CINAHL, PubMed, the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials and a number of grey literature sources. Titles and abstracts were screened by one researcher. Relevant full texts were independently checked by two researchers against eligibility criteria. Results: Fifty-three studies were conducted across twenty-one countries. The majority of studies (n = 39) were conducted in high-income countries. All measured the extent of exposure to outdoor food marketing, twelve also assessed power and three measured impact on behavioural or health outcomes. Criteria used to define outdoor food marketing and methodologies adopted were highly variable across studies. Almost a quarter of advertisements across all studies were for food (mean of 22.1%) and the majority of advertised foods were unhealthy (mean of 63%). The evidence on differences in exposure by SES is heterogenous, which makes it difficult to draw conclusions, however the research suggests that ethnic minority groups have a higher likelihood of exposure to food marketing outdoors. The most frequent persuasive creative strategies were premium offers and use of characters. There was limited evidence on the relationship between exposure to outdoor food marketing and eating behaviour or health outcomes. Conclusions: This review highlights the extent of unhealthy outdoor food marketing globally and the powerful methods used within this marketing. There is a need for consistency in defining and measuring outdoor food marketing to enable comparison across time and place. Future research should attempt to measure direct impacts on behaviour and health
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