Endurance test and evaluation of alkaline water electrolysis cells

Utilization in the development of multi-kW low orbit power systems is discussed. The following technological developments of alkaline water electrolysis cells for space power application were demonstrated: (1) four 92.9 cm2 single water electrolysis cells, two using LST's advanced anodes and two using LST's super anodes; (2) four single cell endurance test stands for life testing of alkaline water electrolyte cells; (3) the solid performance of the advanced electrode and 355 K; (4) the breakthrough performance of the super electrode; (5) the four single cells for over 5,000 hours each significant cell deterioration or cell failure. It is concluded that the static feed water electrolysis concept is reliable and due to the inherent simplicity of the passive water feed mechanism coupled with the use of alkaline electrolyte has greater potential for regenerative fuel cell system applications than alternative electrolyzers. A rise in cell voltage occur after 2,000-3,000 hours which was attributed to deflection of the polysulfone end plates due to creepage of the thermoplastic. More end plate support was added, and the performance of the cells was restored to the initial performance level

Solar cell radiation response near the interface of different atomic number materials

The response of cobalt 60 irradiated N/P silicon solar cells was measured as a function of the atomic number of the medium adjacent to the cell and the direction of the gamma ray beam. The interpositioning of various thicknesses of aluminum between the adjacent material and the cell had the effect of moving the cell to various locations in an approximate monatomic numbered medium. Using this technique the solar cell response was determined at various distances from the interface for gold and beryllium. The results were compared with predictions based upon ionization chamber measurements of dose perturbations in aluminum and found to agree within five percent. Ionization chamber data was then used to estimate the influence of various base contact materials

Static Feed Water Electrolysis Subsystem Testing and Component Development

A program was carried out to develop and test advanced electrochemical cells/modules and critical electromechanical components for a static feed (alkaline electrolyte) water electrolysis oxygen generation subsystem. The accomplishments were refurbishment of a previously developed subsystem and successful demonstration for a total of 2980 hours of normal operation; achievement of sustained one-person level oxygen generation performance with state-of-the-art cell voltages averaging 1.61 V at 191 ASF for an operating temperature of 128F (equivalent to 1.51V when normalized to 180F); endurance testing and demonstration of reliable performance of the three-fluid pressure controller for 8650 hours; design and development of a fluid control assembly for this subsystem and demonstration of its performance; development and demonstration at the single cell and module levels of a unitized core composite cell that provides expanded differential pressure tolerance capability; fabrication and evaluation of a feed water electrolyte elimination five-cell module; and successful demonstration of an electrolysis module pressurization technique that can be used in place of nitrogen gas during the standby mode of operation to maintain system pressure and differential pressures

Ultra-high speed electro-optical systems employing fiber optics final report

Ultrahigh speed electro-optical systems employing fiber optic

Self-interaction errors in density functional calculations of electronic transport

All density functional calculations of single-molecule transport to date have used continuous exchange-correlation approximations. The lack of derivative discontinuity in such calculations leads to the erroneous prediction of metallic transport for insulating molecules. A simple and computationally undemanding atomic self-interaction correction greatly improves the agreement with experiment for the prototype Au/dithiolated-benzene/Au junction.Comment: 4 pages. Also available at http://www.smeagol.tcd.i

Valuing Access to our Public Lands: A Unique Public Good Pricing Experiment

We report the findings of a unique nation-wide experiment to price access to our public lands. In 2004, the U.S. Federal Lands Recreation Enhancement Act mandated the creation of a new annual pass to cover all federal recreation sites that charge an entrance or access fee. Our task was to assist federal policymakers in determining an appropriate price for this new pass. Toward that end, we administered a contingent valuation phone survey to over 3700 households to estimate households willingness to pay (WTP) for the new pass at a variety of different prices. Our innovative experimental design allows us to estimate the degree of hypothetical bias in the sample and calibrate our WTP estimates to reflect actual purchasing decisions. In a sample of the general U.S. population most of whom have little experience with similar federal passes respondents tend to greatly exaggerate their WTP for the pass when contrasted with previous pass sales. A sample of recent pass purchasers, however, exhibits little bias. This confirms recent research showing that market experience can be an effective means to mitigate hypothetical bias.Land Economics/Use,

Four new species of Cymatodera Gray from central and southern Mexico (Coleoptera, Cleridae, Tillinae)

Citation: Burke, A. F., Rifkind, J., & Zolnerowich, G. (2015). Four new species of Cymatodera Gray from central and southern Mexico (Coleoptera, Cleridae, Tillinae). Zookeys(513), 105-121. doi:10.3897/zookeys.513.9935Four new species of Cymatodera are described from Mexico: C. tortuosa Burke & Rifkind, sp. n. from Hidalgo and Tamaulipas; C. ortegae Burke, sp. n. from Colima, Jalisco and Michoacan; C. gerstmeieri Burke & Rifkind, sp. n. from Chiapas; and C. mixteca Burke & Rifkind, sp. n. from Puebla and Guerrero. Male genitalia and other characters of taxonomic value are illustrated

Addressing environmental and atmospheric challenges for capturing high-precision thermal infrared data in the field of astro-ecology

Using thermal infrared detectors mounted on drones, and applying techniques from astrophysics, we hope to support the field of conservation ecology by creating an automated pipeline for the detection and identification of certain endangered species and poachers from thermal infrared data. We test part of our system by attempting to detect simulated poachers in the field. Whilst we find that we can detect humans hiding in the field in some types of terrain, we also find several environmental factors that prevent accurate detection, such as ambient heat from the ground, absorption of infrared emission by the atmosphere, obscuring vegetation and spurious sources from the terrain. We discuss the effect of these issues, and potential solutions which will be required for our future vision for a fully automated drone-based global conservation monitoring system.Comment: Published in Proceedings of SPIE Astronomical Telescopes and Instrumentation 2018. 8 pages, 3 figure

Microwave Spectroscopy

Contains reports on three research projects