Explore the vast range of titles available.

In the past decade CubeSats have made their way into the spotlight. They have evolved from small, university educational opportunities, to industry and governments using them make new discoveries and monetize space. However, with the small, constrained CubeSat form factor; there is often a need to expand the CubeSat through deployable mechanisms once the satellite is in space. This paper is a survey of deployable structures and their actuating mechanisms for CubeSats. The goal of this paper is to provide the applications within which deployable structures have been used in the past for CubeSats, the mechanisms with regards to how they deploy, the lessons learned, and limitations of the various types of deployables. The inputs to this paper come from a relational database in development to track launched CubeSat missions with deployable structures. From this database we can find insightful trends. This paper specifically focuses on the first decade of CubeSat deployables, from 2000 to 2010.

The Cosmic Dark Ages represent the period in the early evolution of the Universe, starting immediately after the decoupling of CMB photons from matter, and ending with the formation of the first stars and galaxies. The HI signal from the neutral hydrogen atoms is the only mechanism for us to understand this crucial phase in the cosmological history of the Universe and answer fundamental questions about the validity of the standard cosmological model, dark matter physics, and inflation. Due to cosmological redshift, this signal is now only observable in the 3-30~MHz frequency band, which is blocked from reaching the surface of the Earth by the ionosphere. In this paper, we present the design of the Lunar Crater Radio Telescope that intends to carry out unprecedented measurements of this signal by deploying a kilometer-sized parabolic reflector mesh inside a lunar crater on the far side of the Moon and suspending a receiver at its focus.

We propose a novel design for a lightweight, high-performance space-based solar power array combined with power beaming capability for operation in geosynchronous orbit and transmission of power to Earth. We use a modular configuration of small, repeatable unit cells, called tiles, that each individually perform power collection, conversion, and transmission. Sunlight is collected via lightweight parabolic concentrators and converted to DC electric power with high efficiency III-V photovoltaics. Several CMOS integrated circuits within each tile generates and controls the phase of multiple independently-controlled microwave sources using the DC power. These sources are coupled to multiple radiating antennas which act as elements of a large phased array to beam the RF power to Earth. The power is sent to Earth at a frequency chosen in the range of 1-10 GHz and collected with ground-based rectennas at a local intensity no larger than ambient sunlight. We achieve significantly reduced mass compared to previous designs by taking advantage of solar concentration, current CMOS integrated circuit technology, and ultralight structural elements. Of note, the resulting satellite has no movable parts once it is fully deployed and all beam steering is done electronically. Our design is safe, scalable, and able to be deployed and tested with progressively larger configurations starting with a single unit cell that could fit on a cube satellite. The design reported on here has an areal mass density of 160 g/m2 and an end-to-end efficiency of 7-14%. We believe this is a significant step forward to the realization of space-based solar power, a concept once of science fiction.

BACKGROUND Poor sleep duration and quality were previously reported to increase the risk of obesity. This study was aimed to evaluate the impact of sleep quality and duration on leptin, appetite, and adiposity in Indonesian adults. METHODS This cross-sectional study recruited adults in Yogyakarta, Indonesia, in 2016. Sleep quality was assessed using the Pittsburgh sleep quality index, appetite was evaluated using the community nutrition appetite questionnaire, and dietary intake was assessed by interviews using the semi-quantitative food frequency questionnaire. Sleep duration was also asked. Obesity indices were measured using the body mass index (BMI), waist-hip circumference, and percentage of body fat. Leptin was analyzed using the enzyme-linked immunosorbent assay. A Spearman analysis was done to evaluate the correlation between sleep quality, sleep duration, anthropometric measures, dietary intake, appetite, and leptin. RESULTS 244 adults participated in this study. This study showed that lower sleep quality and duration was significantly correlated with higher body weight (r = 0.129, p = 0.043 and r = −0.228, p<0.001), BMI (r = 0.176, p = 0.006 and r = −0.202, p = 0.001), and waist circumference (r = 0.179, p = 0.005 and r = −0.254, p<0.001). There was a correlation between poor sleep quality and higher leptin concentration (r = 0.186, p = 0.004). Sleep quality and duration were not associated with appetite (r = 0.109, p = 0.109 and r = −0.043, p = 0.500). CONCLUSIONS This study found that lower sleep quality was correlated with higher BMI, higher leptin concentration, but not appetite.

We address the challenge of making spatial audio datasets by proposing a shared mechanized recording space that can run custom acoustic experiments: a Mechatronic Acoustic Research System (MARS). To accommodate a wide variety of experiments, we implement an extensible architecture for wireless multi-robot coordination which enables synchronized robot motion for dynamic scenes with moving speakers and microphones. Using a virtual control interface, we can remotely design automated experiments to collect large-scale audio data. This data is shown to be similar across repeated runs, demonstrating the reliability of MARS. We discuss the potential for MARS to make audio data collection accessible for researchers without dedicated acoustic research spaces.