SiO overcoating and polishing of CFRP telescope panels

Development of carbon fiber reinforces plastic (CFRP) panel overcoating and polishing is structured in two parts. The first part utilized a short series of experiments to determine the feasibility of overcoating and polishing CFRP panels, and the second part employes a systematic approach to optimize techniques learned. Questions which required answers in the initial investigation are summarized. Tests were performedin the Steward Observatory's 2.2 Meter Vacuum Coating Chamber and began with 3 cm square pieces of CFRP facesheet material. Next, a 10 cm square and one-inch-thick CFPR-Aluminum core panel was tested. Tests were then conducted on a 0.5-meter-square Dornier panel (QUAD 4) with CFRP facesheets on two-inch aluminum Flexcore. To complete the initial study, a previously characterized 0.5 m Dornier panel (QUAD 23) was coated and hand polished. The mirror's optical performance was not affected by the SiO coating

Low temperature optical testing of CFRP telescope panels

Since 1984, low temperature optical tests were made of very lightweight mirror panels for use in balloon and space infrared and submillimeter telescopes. In order to accomplish this testing, an ambient pressure 0.5 meter test chamber operating from 20 to -80 C, developed techniques for measuring non-optical quality mirrors with phase modulation 10.6 micron interferometry, and created the interferogram reduction program. During the course of the program, nineteen mirrors from four manufactures were tested: carbon fiber reinforced plastic (CFRP) aluminum honeycomb sandwich panel mirrors, a CFRP sandwich panel with an added glass facesheet, and carbon fiber reinforced glass panels. The results of the panel development and test program are summarized

Two-dimensional numerical modeling of a proposed freshwater diversion from the Bonnet Carre Spillway to the Labranche wetlands

Engineered modifications to the lower Mississippi River within the past century have limited the magnitude and frequency of flood events in wetlands along the Louisiana coast. Without this natural delivery of freshwater, sediment, and nutrients, the ecological health of these wetlands are now degrading. A recent study within the Bonnet Carre Spillway has revealed that the 7,623 acres of floodway between the Mississippi River and Lake Pontchartrain is one of the few areas in Louisiana that is actively accreting land as a result of pulsed sediment-laden freshwater input during high discharge events in the Mississippi River. On the other hand, the productivity of the spillway region is geographically juxtaposed to the deterioration of the Labranche wetlands directly to the east, which have lost an extensive amount of marsh and swamp land to open water since becoming hydrologically disconnected from the river in the 1930’s. A two-dimensional finite-element numerical model of the Mississippi River, Bonnet Carre Spillway, Lake Pontchartrain, and Labranche wetlands is presented, which is used to examine the hydrodynamics of a freshwater input in the Labranche wetlands via a hypothetical diversion channel through the eastern guide levee of the Bonnet Carre Spillway. Flow velocities, water distribution patterns, and residence time distributions are used to highlight the potential for reintroducing river water and resources to these degrading wetlands

Reinforcement Learning for Planning Heuristics

Informed heuristics are essential for the success of heuristic search algorithms. But, it is difficult to develop a new heuris- tic which is informed on various tasks. Instead, we propose a framework that trains a neural network as heuristic for the tasks it is supposed to solve. We present two reinforcement learning approaches to learn heuristics for fixed state spaces and fixed goals. Our first approach uses approximate value iteration, our second ap- proach uses searches to generate training data. We show that in some domains our approaches outperform previous work, and we point out potentials for future improvements

Analyzing group communication dynamics and content in a common-pool resource experiment

Unidad de excelencia María de Maeztu CEX2019-000940-MWe study costly communication in a common-pool resource (CPR) experiment as a proxy for two different forms of participatory processes: as a public good and as a club good. A public communication meeting, representing centralized participatory processes, occurs when all group members' monetary contributions reach a specified threshold. Club communication meetings, representing networked participatory processes, follow only among those members of the group who pay a communication fee. We test whether the way costly communication is provided affects the willingness of participants to contribute to communication, as well as the dynamics of such payments, and the content of communication. This is done by analyzing contributions to communication and communication content of 100 real-life resource users participating in a lab-in-field experiment. We find that contributions towards communication are higher when communication is public, and that club communication features more frequent but less inclusive communication meetings. Also, communication content is more oriented towards addressing the collective action problem associated with the management of the resource when communication groups are attended by all participants. The identified differences between the two ways to provide for communication can inform policies and the design of participatory processes in natural resource governance

Earth observation for exposome mapping of Germany: analyzing environmental factors relevant to non-communicable diseases

Non-communicable diseases - NCDs - (e.g., asthma, cancer, or diabetes) are a major concern for society and medicine. According to the World Health Organization, NCDs are responsible for > 70 % of global premature deaths. Apart from increasing mortality, these diseases strain one’s immune system which leads to higher susceptibility to transmittable diseases. NCD-susceptibility depends on the genome (genetic predisposition), behavior (lifestyle), and exposome of a person. The exposome is a composition of environmental parameters such as exposure to air pollution, noise, extreme temperatures, or surrounding greenness. Using Earth Observation data, the majority of factors making up the exposome can be monitored over long periods of time at high resolution and with nearly global coverage. Still, exposome maps and products communicating NCD risk are not widely available. In this study, we utilize eight land surface datasets (distance to green spaces, distance to blue spaces, temperature, noise from industry, as well as road, rail, and air traffic, and light pollution) as well as two air pollution datasets (PM2.5 and NO2) to map health-relevant environmental exposure. We use an established cumulative approach and incorporate exposure-response relationships from scientific literature to map environments that impact public health for the complete area of Germany. We present results communicating exposure relevant to myocardial infarction risk. The methodology is transferable to other NCDs and other areas of interest. In the context of the global health burden from NCDs and ongoing global change, this approach supplies findings for communicating health-relevant exposure