VELOX – A Demonstration Facilility for Lunar Oxygen Extraction in a Laboratory Environment

The ultimate goal of a permanent human presence on the Moon is discussed intensively within the global lunar community. Obviously, such an effort poses stringent demands not only on the technology but also on logistics, especially considering the important aspects of masses and volume for materials and replenishments of consumables. On-site propellant production (i.e. liquid oxygen) is one of the main needs and would lead to more efficient return-to-Earth or further exploration missions. Additionally, the supply of breathable air and water for the survival of the crew on the lunar surface is also a major aspect. Thus, large effort is put into the development and research of technologies for in-situ resources utilization (ISRU) to drastically reduce the required supply from Earth and to increase the level of autonomy of a lunar outpost. The major resource on the Moon for such a purpose is regolith, which covers the first meters of the lunar surface and contains about 45% of mineralogically bounded Oxygen in terms of mass. By using adequate processing methods of this material, one could be able to extract valuable minerals and volatiles for further utilization. At DLR Bremen a compact and flexible lab experimenting facility has been developed, built and tested, which shall demonstrate the feasibility of the process by extracting oxygen out of lunar regolith, respectively soil simulants and certain minerals in the laboratory case. For this purpose, important boundary conditions have been investigated such as temperatures during the process, chemical reaction characteristics and material properties for the buildup of the facility, which shall be analyzed within this paper. Since it is one of the most elaborated chemical processes regarding ISRU and has comparably low temperature and energy constraints it has been primarily concentrated on the Hydrogen-reduction process which reduces the iron oxide component of Ilmenite (FeTiO3) within the lunar regolith. Based on the obtained results, a first line-out of a planned superior test set-up and infrastructure with pre- and post-processing units such as feeding and extraction is also presented, as well as an analysis of reaction products with common methods. This paper will present the first results of DLR efforts regarding these topics. Finally, important aspects of the future development of the processes and technologies are discussed with special consideration of lunar applicability and with respect to environmental conditions as well as mass and energy constraints

Down By The Nile

https://digitalcommons.library.umaine.edu/mmb-vp/5149/thumbnail.jp

Dream Girl, Give Back My Dream To Me

https://digitalcommons.library.umaine.edu/mmb-vp/4186/thumbnail.jp

Progressive impairment of CaV1.1 function in the skeletal muscle of mice expressing a mutant type 1 Cu/Zn superoxide dismutase (G93A) linked to amyotrophic lateral sclerosis

Background: Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder that is typically fatal within 3–5 years of diagnosis. While motoneuron death is the defining characteristic of ALS, the events that underlie its pathology are not restricted to the nervous system. In this regard, ALS muscle atrophies and weakens significantly before presentation of neurological symptoms. Since the skeletal muscle L-type Ca2+ channel (CaV1.1) is a key regulator of both mass and force, we investigated whether CaV1.1 function is impaired in the muscle of two distinct mouse models carrying an ALS-linked mutation. Methods: We recorded L-type currents, charge movements, and myoplasmic Ca2+ transients from dissociated flexor digitorum brevis (FDB) fibers to assess CaV1.1 function in two mouse models expressing a type 1 Cu/Zn superoxide dismutase mutant (SOD1G93A). Results: In FDB fibers obtained from “symptomatic” global SOD1G93A mice, we observed a substantial reduction of SR Ca2+ release in response to depolarization relative to fibers harvested from age-matched control mice. L-type current and charge movement were both reduced by ~40 % in symptomatic SOD1G93A fibers when compared to control fibers. Ca2+ transients were not significantly reduced in similar experiments performed with FDB fibers obtained from “early-symptomatic” SOD1G93A mice, but L-type current and charge movement were decreased (~30 and ~20 %, respectively). Reductions in SR Ca2+ release (~35 %), L-type current (~20 %), and charge movement (~15 %) were also observed in fibers obtained from another model where SOD1G93A expression was restricted to skeletal muscle. Conclusions: We report reductions in EC coupling, L-type current density, and charge movement in FDB fibers obtained from symptomatic global SOD1G93A mice. Experiments performed with FDB fibers obtained from early-symptomatic SOD1G93A and skeletal muscle autonomous MLC/SOD1G93A mice support the idea that events occurring locally in the skeletal muscle contribute to the impairment of CaV1.1 function in ALS muscle independently of innervation status

Restricted isometries for partial random circulant matrices

In the theory of compressed sensing, restricted isometry analysis has become a standard tool for studying how efficiently a measurement matrix acquires information about sparse and compressible signals. Many recovery algorithms are known to succeed when the restricted isometry constants of the sampling matrix are small. Many potential applications of compressed sensing involve a data-acquisition process that proceeds by convolution with a random pulse followed by (nonrandom) subsampling. At present, the theoretical analysis of this measurement technique is lacking. This paper demonstrates that the sth-order restricted isometry constant is small when the number m of samples satisfies m ≳ (s logn)^(3/2), where n is the length of the pulse. This bound improves on previous estimates, which exhibit quadratic scaling

Slepian Beamforming: Broadband Beamforming using Streaming Least Squares

In this paper we revisit the classical problem of estimating a signal as it impinges on a multi-sensor array. We focus on the case where the impinging signal's bandwidth is appreciable and is operating in a broadband regime. Estimating broadband signals, often termed broadband (or wideband) beamforming, is traditionally done through filter and summation, true time delay, or a coupling of the two. Our proposed method deviates substantially from these paradigms in that it requires no notion of filtering or true time delay. We use blocks of samples taken directly from the sensor outputs to fit a robust Slepian subspace model using a least squares approach. We then leverage this model to estimate uniformly spaced samples of the impinging signal. Alongside a careful discussion of this model and how to choose its parameters we show how to fit the model to new blocks of samples as they are received, producing a streaming output. We then go on to show how this method naturally extends to adaptive beamforming scenarios, where we leverage signal statistics to attenuate interfering sources. Finally, we discuss how to use our model to estimate from dimensionality reducing measurements. Accompanying these discussions are extensive numerical experiments establishing that our method outperforms existing filter based approaches while being comparable in terms of computational complexity