ESA Activity Research Articles

New Approach to Synthesizing Cathode PtCo/C Catalysts for Low-Temperature Fuel Cells

The presented study is concerned with a new multi-step method to synthesize PtCo/C materials based on composite CoxOy/C that combines the advantages of different liquid-phase synthesis methods. Based on the results of studying the materials at each stage of synthesis with the TG, XRD, TEM, SEI, TXRF, CV and LSV methods, a detailed overview of the sequential changes in catalyst composition and structure at each stage of the synthesis is presented. The PtCo/C catalyst synthesized with the multi-step method is characterized by a uniform distribution of bimetallic nanoparticles of about 3 nm in size over the surface of the support, which result in its high ESA and ORR activity. The activity study for the synthesized PtCo/C catalyst in an MEA showed better current–voltage characteristics and a higher maximum specific power compared with an MEA based on a commercial Pt/C catalyst. Therefore, the results of the presented study demonstrate high prospects for the developed approach to the multi-step synthesis of PtM/C catalysts, which may enhance the characteristics of proton-exchange membrane fuel cells (PEMFCs).

High School Sport Participation Intensity and Breadth

The purpose of this study was to address the gap in research related to whether measures of participation (intensity and breadth) demonstrated a relationship with academic achievement for 11th grade student athletes (N=128) in a rural Midwestern high school. Anonymous athletic participation and achievement data from 2015-2017 was obtained from the school’s archive and analyzed by correlation, hierarchical regression, and one-way ANOVA. Data derived from statistical analyses demonstrated two outcomes regarding sport participation, ACT, and GPA: (a) Intensity demonstrated no statistical significance to student achievement measured by ACT, however intensity demonstrated a statistically significant relationship to cumulative GPA (p < .05), and (b) ANOVA analysis demonstrated statistically significant differences in breadth and GPA (p < .01) between one sport athletes and three sport athletes. Three sport athletes had statistically significantly higher GPAs than one sport athletes and significantly higher GPAs than two sport athletes. The research was limited to one cross-sectional heterogeneous rural high school population of participants over a three-year period. Furthermore, the study was limited to school-specific athletic participation data as school non-athletic activity and out-of-school activity participation was not available. Results from this study suggest programming and potential practice recommendations for rural school leaders. Future research on ESA sport, activity, and non-school activity participation intensity and breadth related to academic outcomes is justified.

ACIX-Aqua: A global assessment of atmospheric correction methods for Landsat-8 and Sentinel-2 over lakes, rivers, and coastal waters

Atmospheric correction over inland and coastal waters is one of the major remaining challenges in aquatic remote sensing, often hindering the quantitative retrieval of biogeochemical variables and analysis of their spatial and temporal variability within aquatic environments. The Atmospheric Correction Intercomparison Exercise (ACIX-Aqua), a joint NASA – ESA activity, was initiated to enable a thorough evaluation of eight state-of-the-art atmospheric correction (AC) processors available for Landsat-8 and Sentinel-2 data processing. Over 1000 radiometric matchups from both freshwaters (rivers, lakes, reservoirs) and coastal waters were utilized to examine the quality of derived aquatic reflectances (ρ̂w). This dataset originated from two sources: Data gathered from the international scientific community (henceforth called Community Validation Database, CVD), which captured predominantly inland water observations, and the Ocean Color component of AERONET measurements (AERONET-OC), representing primarily coastal ocean environments. This volume of data permitted the evaluation of the AC processors individually (using all the matchups) and comparatively (across seven different Optical Water Types, OWTs) using common matchups. We found that the performance of the AC processors differed for CVD and AERONET-OC matchups, likely reflecting inherent variability in aquatic and atmospheric properties between the two datasets. For the former, the median errors in ρ̂w560 and ρ̂w664 were found to range from 20 to 30% for best-performing processors. Using the AERONET-OC matchups, our performance assessments showed that median errors within the 15–30% range in these spectral bands may be achieved. The largest uncertainties were associated with the blue bands (25 to 60%) for best-performing processors considering both CVD and AERONET-OC assessments. We further assessed uncertainty propagation to the downstream products such as near-surface concentration of chlorophyll-a (Chla) and Total Suspended Solids (TSS). Using satellite matchups from the CVD along with in situ Chla and TSS, we found that 20–30% uncertainties in ρ̂w490≤λ≤743nm yielded 25–70% uncertainties in derived Chla and TSS products for top-performing AC processors. We summarize our results using performance matrices guiding the satellite user community through the OWT-specific relative performance of AC processors. Our analysis stresses the need for better representation of aerosols, particularly absorbing ones, and improvements in corrections for sky- (or sun-) glint and adjacency effects, in order to achieve higher quality downstream products in freshwater and coastal ecosystems.

Experimental approach regarding the ignition of H 2 /O 2 mixtures in vacuum environment

Abstract The paper, elaborated in the framework of the ESA activity Green thruster for attitude control and orbital manoeuvres of small satellites (GREENTH), focuses on the preliminary stages of an experimental program aiming to evaluate the feasibility and to increase the maturity level of a H2/O2 pulsed technology for small scale space propulsion applications. For demonstrating the capability of the H2/O2 mixture to be pulsed and ignited in a vacuum environment, the paper presents the main technical requirements, some addressing the thruster itself, related to system dimensioning, such as the nature of manoeuvres, the thrust level, the minimum impulse bit, the operating conditions, and some addressing the experimental campaign to be performed. The design of the experimental installation has taken into account the demands coming for the challenges and limitations raised by the small-scale satellites (telecommunications satellites or even CubeSats) applications, including vacuum system dimensioning, injection and ignition systems dimensioning and equipment and instrumentation specifications. The testing program covers the selected ranges of operational parameters and the operating sequences, for pulse mode and steady state tests, in order to determine the performance level and to evaluate the pulse repeatability, respectively to demonstrate the process stability.

Investigation of Advanced Components in a High Pressure Single-Cell Electrolyser for the Development of a HP-PEM-ELY Stack as Part of a Regenerative Fuel Cell System

The objective of the presented work, done under current ESA activity (Contract No. 4000109578/13/NL/SC), is the performance and tolerance evaluation of selected components and materials for the development of a High Pressure, Polymer Electrolyte Membrane (PEM) Electrolyser (HP-PEM-ELY) Stack, aiming to operate at 80 bar with a performance output of 0.3 A/cm 2 at 1.6 V. An extensive study was performed on a single-cell high pressure PEM electrolyser manifold, leading to a list of materials with suitable properties and engineering solutions towards operation in space environment. This investigation provided the necessary feedback for the design of a HP-PEM-ELY stack, which is also discussed. The ultimate target of the current ESA activity is to implement research findings, develop and operate a complete regenerative fuel cell system, comprising of a High Temperature Fuel Cell Stack and the HP-PEM-ELY stack. System aspects are briefly discussed.

Gan Transistor in Space Equipments: From Selection to Applications

Two years ago, at ESPC-2014 results of ESA activity on GaN transistor survey has been presented. The main outcome was the existence of an unknown phenomena in silicon MOSFET: the dynamic Rdson.Today we are the time of studying introduction of this technology into products. At least two suppliers (EPC- co & GaN Systems) are proposing stabilized GaN transistors components which are worth spending some time to try to implement in next generation product prototypes.Space applications aren’t very different from terrestrial ones when we speak about benefits of using GaN technology into dc-dc converters: lower losses & more compact designs thanks to higher switching frequencies. Next to reliability analyses proposed by the component vendors to be able to address the automotive markets, there is of course quite a list “space” specific questions that need also to be answered to raise the confidence that GaN will one day be put is orbit: hermetic packaging & assembly on PCBs, radiation harness, reliability impact of radiations, cooling in the absence of air flow, thermal cycling, drivers, deratings to apply…In this article we presents some prototyping results & shares some feedback & concerns about the introduction of GaN into space qualified dc-dc products.

NELIOTA: ESA's new NEO lunar impact monitoring project with the 1.2m telescope at the National Observatory of Athens

AbstractNELIOTA is a new ESA activity launched at the National Observatory of Athens in February 2015 aiming to determine the distribution and frequency of small near-earth objects (NEOs) via lunar monitoring. The project involves upgrading the 1.2m Kryoneri telescope of the National Observatory of Athens, building a two fast-frame camera instrument, and developing a software system, which will control the telescope and the cameras, process the images and automatically detect NEO impacts. NELIOTA will provide a web-based user interface, where the impact events will be reported and made available to the scientific community and the general public. The objective of this 3.5 year activity is to design, develop and implement a highly automated lunar monitoring system, which will conduct an observing campaign for 2 years in search of NEO impact flashes on the Moon. The impact events will be verified, characterised and reported. The 1.2m telescope will be capable of detecting flashes much fainter than current, small-aperture, lunar monitoring telescopes. NELIOTA is therefore expected to characterise the frequency and distribution of NEOs weighing as little as a few grams.

Student Awards for Excellence in Ecology

Murray F. Buell had a long and distinguished record of service and accomplishment in the Ecological Society of America. Among other things, he ascribed great importance to the participation of students in meetings and to excellence in the presentation of papers. To honor his selfless dedication to the younger generation of ecologists, the Murray F. Buell Award for Excellence in Ecology is given to a student for the outstanding oral paper presented at the ESA Annual Meeting. E. Lucy Braun, an eminent plant ecologist and one of the charter members of the Society, studied and mapped the deciduous forest regions of eastern North America and described them in her classic book, The Deciduous Forests of Eastern North America. To honor her, the E. Lucy Braun Award for Excellence in Ecology is given to a student for the outstanding poster presentation at the ESA Annual Meeting. A candidate for these awards must be an undergraduate, a graduate student, or a recent doctorate not more than 9 months past graduation at the time of the meeting. The paper or poster must be presented as part of the program sponsored by the Ecological Society of America, but the student need not be an ESA member. To be eligible for these awards the student must be the sole or senior author of the oral paper (Note: symposium talks are ineligible) or poster. Papers and posters will be judged on the significance of ideas, creativity, quality of methodology, validity of conclusions drawn from results, and clarity of presentation. While all students are encouraged to participate, winning papers and posters typically describe fully completed projects. The students selected for these awards will be announced in the ESA Bulletin following the Annual Meeting. A certificate, a check for $500, and up to $700 to be used for travel and/or lodging for the Annual Meeting will be presented to each recipient at the next ESA Annual Meeting. If you wish to be considered for either of these awards at the 2015 Annual Meeting, you must send the following to the Chair of the Student Awards Subcommittee: (1) the application form on the back of this page, (2) a copy of your abstract, and (3) a 250-word or less description of why/how the research presented will advance the field of ecology. Because of the large number of applications for the Buell and Braun awards in recent years, applicants may be pre-screened prior to the meeting, based on the quality of the abstract and this description of the significance of their research. The application form, abstract, and research justification must be sent by e-mail (greatly preferred: [email protected]) or mail to The Ecological Society of America, Attn: Buell/Braun Awards, 1990 M St, NW, Suite 700, Washington, DC 20036. The deadline for submission of form and abstract is 1 March 2015; applications sent after 1 March 2015 will not be considered. This submission is in addition to the regular abstract submission. Buell/Braun participants who fail to notify the B/B Chair by 1 May of withdrawal from the meeting will be ineligible, barring exceptional circumstances, for consideration in the future. Electronic versions of the Application Form are available on the ESA web site, or you can send an e-mail to [email protected] and request that an electronic version be sent to you as an attachment. Judges are needed to evaluate candidates for the Murray F. Buell Award for the outstanding oral presentation by a student and the E. Lucy Braun Award for the outstanding poster presentation by a student at the Annual ESA Meeting at Baltimore, Maryland, in 2015. We need to provide each candidate with at least four judges competent in the specific subject of the presentation. Each judge is asked to evaluate 3–5 papers and/or posters. Current graduate students are not eligible to judge. This is a great way to become involved in an important ESA activity. We desperately need your help! Please complete and send this form by mail or e-mail to the Ecological Society of America, Attn: Buell/Braun Awards, 1990 M Street, NW, Suite 700, Washington, DC 20036, e-mail: [email protected]. If you have judged in the past several years, this information is on file. If you do not have to update your information, simply send an e-mail message, “Yes, I can judge this year.” Please refer to the PDF of this article for the application form.

ESA's Fourth Decade: the Post‐War Years

ESA's Fourth Decade: the Post‐War Years

Fall 2013 ESA Election Results

Fall 2013 ESA Election Results

Announcements

Announcements

Request for Student Award Judges

Judges are needed to evaluate candidates for the Murray F. Buell Award for the outstanding oral presentation by a student and the E. Lucy Braun Award for the outstanding poster presentation by a student at the Annual ESA Meeting at Portland, Oregon in 2012. We need to provide each candidate with at least four judges competent in the specific subject of the presentation. Each judge is asked to evaluate 3–5 papers and/or posters. Current graduate students are not eligible to judge. This is a great way to become involved in an important ESA activity. We desperately need your help! Please complete and send this form by mail or e-mail to the Ecological Society of America, Attn: Buell/Braun Awards, 1990 M Street, NW, Suite 700, Washington, DC 20036, e-mail:buellbraun@esa.org. If you have judged in the past several years, this information is on file. If you do not have to update your information, simply send an e-mail message, "Yes, I can judge this year." Please refer to the PDF of this article for the application form.

Ku Band Hemispherical Fully Electronic Antenna for Aircraft in Flight Entertainment

The results obtained in the frame of the ESA activity “Advanced Antenna Concepts For Aircraft In Flight Entertainment” are presented. The aim of the activity consists in designing an active antenna able to guarantee the Ku band link between an aircraft and a geostationary satellite in order to provide in flight entertainment services. The transmit-receive antenna generates a single narrow beam to be steered electronically in a half sphere remaining compliant with respect to stringent requirements in terms of pattern shape, polarization alignment, EIRP, G/T, and using customized electronic devices. At the same time, the proposed solution should be competitive in terms of cost and complexity.