Design issues in the GCF Mark 4 development

Some of the major design problems facing the computer based Ground Communications Facility (GCF) Digital Communication System for the Mark 4 Network Consolidation Program are discussed. The solutions to each as implemented in the software of the GCF Operation Programs are proposed

Postcard: Souvenir National Encampment G.A.R, Kansas City, 1916

This color printed postcard features an illustration of an American flag on the left side of the card. There is blue and red text printed at the top. There is handwriting on the front and back of the card.https://scholars.fhsu.edu/tj_postcards/1533/thumbnail.jp

Deep Space Network information system architecture study

The purpose of this article is to describe an architecture for the Deep Space Network (DSN) information system in the years 2000-2010 and to provide guidelines for its evolution during the 1990s. The study scope is defined to be from the front-end areas at the antennas to the end users (spacecraft teams, principal investigators, archival storage systems, and non-NASA partners). The architectural vision provides guidance for major DSN implementation efforts during the next decade. A strong motivation for the study is an expected dramatic improvement in information-systems technologies, such as the following: computer processing, automation technology (including knowledge-based systems), networking and data transport, software and hardware engineering, and human-interface technology. The proposed Ground Information System has the following major features: unified architecture from the front-end area to the end user; open-systems standards to achieve interoperability; DSN production of level 0 data; delivery of level 0 data from the Deep Space Communications Complex, if desired; dedicated telemetry processors for each receiver; security against unauthorized access and errors; and highly automated monitor and control

Team sport athletes’ perceptions and use of recovery strategies: a mixed-methods survey study

Background: A variety of recovery strategies are used by athletes, although there is currently no research that investigates perceptions and usage of recovery by different competition levels of team sport athletes. Methods: The recovery techniques used by team sport athletes of different competition levels was investigated by survey. Specifically this study investigated if, when, why and how the following recovery strategies were used: active land-based recovery (ALB), active water-based recovery (AWB), stretching (STR), cold water immersion (CWI) and contrast water therapy (CWT). Results: Three hundred and thirty-one athletes were surveyed. Fifty-seven percent were found to utilise one or more recovery strategies. Stretching was rated the most effective recovery strategy (4.4/5) with ALB considered the least effective by its users (3.6/5). The water immersion strategies were considered effective/ineffective mainly due to psychological reasons; in contrast STR and ALB were considered to be effective/ineffective mainly due to physical reasons. Conclusions: This study demonstrates that athletes may not be aware of the specific effects that a recovery strategy has upon their physical recovery and thus athlete and coach recovery education is encouraged. This study also provides new information on the prevalence of different recovery strategies and contextual information that may be useful to inform best practice among coaches and athletes

Medical device design for adolescent adherence and developmental goals: a case study of a cystic fibrosis physiotherapy device

Purpose: This study investigates the psychosocial aspects of adolescent medical device use and the impact on adolescent adherence and goals for the transitional years between child and adulthood. Patients and methods: Interviews were carried out with 20 adolescents with cystic fibrosis, investigating adolescent medical device use and experiences in relation to their personal and social lives and development through the adolescent years. The qualitative dataset was thematically examined using a content analysis method. Results: The results show that adolescent users of medical technologies want their independence and capabilities to be respected. Adolescent adherence to medical device use was associated with short- and long-term motivations, where older adolescents were able to comprehend the longer-term benefits of use against short-term inconvenience more acutely than younger adolescents. It was suggested that medical devices could provide a tool for communication with families and clinicians and could support adolescents as they take responsibility for managing their condition. Themes of “fitting into teenage life” and “use in the community” were associated with adolescents' needs to form their own identity and have autonomy. Conclusion: This study shows that adolescent needs regarding medical device use are complex. It provides evidence to suggest that devices designed inclusively for adolescents may lead to improved adherence and also facilitate transition through the adolescent years and achievement of adolescent goals

Cassiopeia A: dust factory revealed via submillimetre polarimetry

If Type-II supernovae - the evolutionary end points of short-lived, massive stars - produce a significant quantity of dust (>0.1 M_sun) then they can explain the rest-frame far-infrared emission seen in galaxies and quasars in the first Gyr of the Universe. Submillimetre observations of the Galactic supernova remnant, Cas A, provided the first observational evidence for the formation of significant quantities of dust in Type-II supernovae. In this paper we present new data which show that the submm emission from Cas A is polarised at a level significantly higher than that of its synchrotron emission. The orientation is consistent with that of the magnetic field in Cas A, implying that the polarised submm emission is associated with the remnant. No known mechanism would vary the synchrotron polarisation in this way and so we attribute the excess polarised submm flux to cold dust within the remnant, providing fresh evidence that cosmic dust can form rapidly. This is supported by the presence of both polarised and unpolarised dust emission in the north of the remnant, where there is no contamination from foreground molecular clouds. The inferred dust polarisation fraction is unprecedented (f_pol ~ 30%) which, coupled with the brief timescale available for grain alignment (<300 yr), suggests that supernova dust differs from that seen in other Galactic sources (where f_pol=2-7%), or that a highly efficient grain alignment process must operate in the environment of a supernova remnant.Comment: In press at MNRAS, 10 pages, print in colou

Forehead reflectance photoplethysmography to monitor heart rate: preliminary results from neonatal patients

Around 5%–10% of newborn babies require some form of resuscitation at birth and heart rate (HR) is the best guide of efficacy. We report the development and first trial of a device that continuously monitors neonatal HR, with a view to deployment in the delivery room to guide newborn resuscitation. The device uses forehead reflectance photoplethysmography (PPG) with modulated light and lock-in detection. Forehead fixation has numerous advantages including ease of sensor placement, whilst perfusion at the forehead is better maintained in comparison to the extremities. Green light (525 nm) was used, in preference to the more usual red or infrared wavelengths, to optimize the amplitude of the pulsatile signal. Experimental results are presented showing simultaneous PPG and electrocardiogram (ECG) HRs from babies (n = 77), gestational age 26–42 weeks, on a neonatal intensive care unit. In babies ≥32 weeks gestation, the median reliability was 97.7% at ±10 bpm and the limits of agreement (LOA) between PPG and ECG were +8.39 bpm and −8.39 bpm. In babies <32 weeks gestation, the median reliability was 94.8% at ±10 bpm and the LOA were +11.53 bpm and −12.01 bpm. Clinical evaluation during newborn deliveries is now underway

Precision control of thermal transport in cryogenic single-crystal silicon devices

We report on the diffusive-ballistic thermal conductance of multi-moded single-crystal silicon beams measured below 1 K. It is shown that the phonon mean-free-path $\ell$ is a strong function of the surface roughness characteristics of the beams. This effect is enhanced in diffuse beams with lengths much larger than $\ell$, even when the surface is fairly smooth, 5-10 nm rms, and the peak thermal wavelength is 0.6 $\mu$m. Resonant phonon scattering has been observed in beams with a pitted surface morphology and characteristic pit depth of 30 nm. Hence, if the surface roughness is not adequately controlled, the thermal conductance can vary significantly for diffuse beams fabricated across a wafer. In contrast, when the beam length is of order $\ell$, the conductance is dominated by ballistic transport and is effectively set by the beam area. We have demonstrated a uniformity of $\pm$8% in fractional deviation for ballistic beams, and this deviation is largely set by the thermal conductance of diffuse beams that support the micro-electro-mechanical device and electrical leads. In addition, we have found no evidence for excess specific heat in single-crystal silicon membranes. This allows for the precise control of the device heat capacity with normal metal films. We discuss the results in the context of the design and fabrication of large-format arrays of far-infrared and millimeter wavelength cryogenic detectors