119 research outputs found
A Tale of Two Chambers: Iterative Approaches and Lessons Learned from Life Support Systems Testing in Altitude Chambers
With a brand new fire set ablaze by a serendipitous convergence of events ranging from a science fiction novel and movie ("The Martian"), to ground-breaking recent discoveries of flowing water on its surface, the drive for the journey to Mars seems to be in a higher gear than ever before. We are developing new spacecraft and support systems to take humans to the Red Planet, while scientists on Earth continue using the International Space Station as a laboratory to evaluate the effects of long duration space flight on the human body. Written from the perspective of a facility test director rather than a researcher, and using past and current life support systems tests as examples, this paper seeks to provide an overview on how facility teams approach testing, the kind of information they need to ensure efficient collaborations and successful tests, and how, together with researchers and principal investigators, we can collectively apply what we learn to execute future tests
Functionalised metal-organic frameworks: a novel approach to stabilising single metal atoms
We have investigated the potential of metal-organic frameworks for immobilising single atoms of transition metals using a model system of Pd supported on NH2-MIL-101(Cr). Our Transmission Electron Microscopy and in-situ Raman spectroscopy results give evidence for the first time that functionalised metal-organic frameworks may support, isolate and stabilise single atoms of palladium. Using Thermal Desorption Spectroscopy we were able to evaluate the proportion of single Pd atoms. Furthermore, in a combined theoretical-experimental approach, we show that the H-H bonds in a H2 molecule elongate by over 15% through the formation of a complex with single atoms of Pd. Such deformation would affect any hydrogenation reaction and thus the single atoms supported on metal-organic frameworks may become promising single atom catalysts in the future
PI-in-a-Box
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1998.Includes bibliographical references (p. 77-78).Principal Investigator-in-a-Box (abbreviated [PI]) is an expert system designed to assist astronauts with the performance of an experiment outside their field of expertise when contact with the Principal Investigators on the ground is not allowed or impossible. The latest version of [PI] was designed to assist with the calibration and troubleshooting procedures of the Neurolab Sleep and Respiration Experiment, launched on the Space Shuttle Columbia on April 17, 1998. The role of [PI] in this application is to display physiological signals in real time during the pre-sleep instrumentation period, and to alert the astronauts when a poor signal quality (due to incorrect application of the instrumentation or a hardware malfunction) is detected. As the first expert system ever designed to be an integral part of a Space Life Sciences experiment, a formal and structured evaluation of the efficacy of such a system is unprecedented. The study presented in this thesis is a preliminary assessment of the efficacy of [PI] with the "poor signal quality detection" process. The twelve subjects used for this study were required to monitor a set of pre-recorded physiological signals and identify signal artifacts displayed on the screen. Every subject performed the experiment twice, once with the assistance of [PI] and once without, in a balanced design. Results indicated a positive effect of [PI] on overall time to detect anomalies. The combination of previous exposure to signal monitoring (training) and [PI] assistance was a significant factor in the improvement of overall reaction time. Also, the assistance of the expert system dramatically reduced the number of undetected anomalies. Having been designed for a life sciences experiment, the evaluation of [PI] was modeled after that of ground-based medical information systems. As for most medical expert systems, evaluation is an iterative process, and this study represents the first step, providing many insights and recommendations for more in-depth studies in the future, as well as exploring possible ramifications and expansions of the uses of expert systems in space.by Gianluca Callini.S.M
Storage of Renewable Energy by Reduction of CO2 with Hydrogen
The main difference between the past energy economy during the industrialization period which was mainly based on mining of fossil fuels, e.g. coal, oil and methane and the future energy economy based on renewable energy is the requirement for storage of the energy fluxes. Renewable
energy, except biomass, appears in time- and location-dependent energy fluxes as heat or electricity upon conversion. Storage and transport of energy requires a high energy density and has to be realized in a closed materials cycle. The hydrogen cycle, i.e. production of hydrogen from water
by renewable energy, storage and use of hydrogen in fuel cells, combustion engines or turbines, is a closed cycle. However, the hydrogen density in a storage system is limited to 20 mass% and 150 kg/m3 which limits the energy density to about half of the energy density in fossil
fuels. Introducing CO2 into the cycle and storing hydrogen by the reduction of CO2 to hydrocarbons allows renewable energy to be converted into synthetic fuels with the same energy density as fossil fuels. The resulting cycle is a closed cycle (CO2 neutral)
if CO2 is extracted from the atmosphere. Today's technology allows CO2 to be reduced either by the Sabatier reaction to methane, by the reversed water gas shift reaction to CO and further reduction of CO by the Fischer–Tropsch synthesis (FTS) to hydrocarbons or
over methanol to gasoline. The overall process can only be realized on a very large scale, because the large number of by-products of FTS requires the use of a refinery. Therefore, a well-controlled reaction to a specific product is required for the efficient conversion of renewable energy
(electricity) into an easy to store liquid hydrocarbon (fuel). In order to realize a closed hydrocarbon cycle the two major challenges are to extract CO2 from the atmosphere close to the thermodynamic limit and to reduce CO2 with hydrogen in a controlled reaction to a
specific hydrocarbon. Nanomaterials with nanopores and the unique surface structures of metallic clusters offer new opportunities for the production of synthetic fuels
Italian consensus statement (2020) on return to play after lower limb muscle injury in football (soccer)
Return to play (RTP) decisions in football are currently based on expert opinion. No consensus guideline has been published to demonstrate an evidence-based decision-making process in football (soccer). Our aim was to provide a framework for evidence-based decision-making in RTP following lower limb muscle injuries sustained in football. A 1-day consensus meeting was held in Milan, on 31 August 2018, involving 66 national and international experts from various academic backgrounds. A narrative review of the current evidence for RTP decision-making in football was provided to delegates. Assembled experts came to a consensus on the best practice for managing RTP following lower limb muscle injuries via the Delphi process. Consensus was reached on (1) the definitions of return to training' and return to play' in football. We agreed on return to training' and RTP in football, the appropriate use of clinical and imaging assessments, and laboratory and field tests for return to training following lower limb muscle injury, and identified objective criteria for RTP based on global positioning system technology. Level of evidence IV, grade of recommendation D
Hydrogen Storage Materials for Mobile and Stationary Applications: Current State of the Art
One of the limitations to the widespread use of hydrogen as an energy carrier is its storage in a safe and compact form. Herein, recent developments in effective high-capacity hydrogen storage materials are reviewed, with a special emphasis on light compounds, including those based on organic porous structures, boron, nitrogen, and aluminum. These elements and their related compounds hold the promise of high, reversible, and practical hydrogen storage capacity for mobile applications, including vehicles and portable power equipment, but also for the large scale and distributed storage of energy for stationary applications. Current understanding of the fundamental principles that govern the interaction of hydrogen with these light compounds is summarized, as well as basic strategies to meet practical targets of hydrogen uptake and release. The limitation of these strategies and current understanding is also discussed and new directions proposed
Mg for hydrogen storage: synthesis, nanostructure and thermodynamics properties
Nowadays alternative energies are an extremely important topic and the possibility of using hydrogen as an energy carrier must be explored. Many problems infer the technological application of this abundant and powerful resource, one of them the possibility of storage.
In the framework of suitable materials for hydrogen storage, magnesium has been the center of this study because it is cheap and the amount of stored hydrogen that it achieves (7.6 wt%) is extremely appealing. Nanostructure helps to overcome the slow hydrogen diffusion and the functionalization of surfaces with transition metals or oxides favors the hydrogen molecule dissociation/recombination.
The aim of this research is the investigation of the metal-hydride transformation in magnesium nanoparticles synthesized by inert-gas condensation, exploiting the fact that they are a simple model system. The so produced nanostructured powder has been analyzed in response to nanoparticles surface functionalization by transition metal clusters, specifically palladium, nickel and titanium, chosen on the basis of their completely different Mg-related phase diagrams. The role of the intermetallic phases formed upon heating and hydrogenation treatments will be presented to provide a comprehensive picture of hydrogen sorption in this class of nanostructured storage materials
A Tale of Two Chambers: Iterative Approaches and Lessons Learned from Life Support Systems Testing in Altitude Chambers
United StatesNASA JSC501ICES501: Life Support Systems Engineering and AnalysisVienna, AustriaGianluca Callini, Jacobs Clear Lake Group at NASA Johnson Space Center, USAThe 46th International Conference on Environmental Systems was held in Vienna, Austria, USA on 10 July 2016 through 14 July 2016.The drive for the journey to Mars is in a higher gear than ever before. We are developing new spacecraft and life support systems to take humans to the Red Planet.
The journey that development hardware takes before its final incarnation in a fully integrated spacecraft can take years, as is the case for the Orion environmental control and life support system (ECLSS).
Through the Pressure Integrated Suit Test (PIST) series, NASA personnel at Johnson Space Center have been characterizing the behavior of a closed loop ECLSS in the event of cabin depressurization. This kind of testing – one of the most hazardous activities performed at JSC – requires an iterative approach, increasing in complexity and hazards). The PIST series, conducted in the Crew and Thermal Systems Division (CTSD) 11-ft Chamber, started with unmanned test precursors before moving to a human-in-the-loop phase, and continues to evolve with the eventual goal of a qualification test for the final system that will be installed on Orion.
Meanwhile, the Human Exploration Spacecraft Testbed for Integration and Advancement (HESTIA) program is an effort to research and develop technologies that will work in concert to support habitation on Mars. September 2015 marked the first unmanned HESTIA test, with the goal of characterizing how ECLSS technologies work together in a closed environment. HESTIA will culminate in crewed testing, but it can benefit from the lessons learned from another test that is farther ahead in its development and life cycle.
Discussing PIST and HESTIA, this paper illustrates how we approach testing, the kind of information that facility teams need to ensure efficient collaborations and successful testing, and how we can apply what we learn to execute future tests
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