Digital Commons Network^™

Gawmerge Expands Gwas Sample Size And Diversity By Combining Array-Based Genotyping And Whole-Genome Sequencing, Ravi Mathur, Fang Fang, Nathan Gaddis, Dana B Hancock, Michael H Cho, John E Hokanson, Laura J Bierut, Sharon M Lutz, Kendra Young, Albert V Smith, Nhlbi Trans-Omics For Precision Medicine (Topmed) Consortium, Edwin K Silverman, Grier P Page, Eric O Johnson

2020-Current year OA Pubs

Genome-wide association studies (GWAS) have made impactful discoveries for complex diseases, often by amassing very large sample sizes. Yet, GWAS of many diseases remain underpowered, especially for non-European ancestries. One cost-effective approach to increase sample size is to combine existing cohorts, which may have limited sample size or be case-only, with public controls, but this approach is limited by the need for a large overlap in variants across genotyping arrays and the scarcity of non-European controls. We developed and validated a protocol, Genotyping Array-WGS Merge (GAWMerge), for combining genotypes from arrays and whole-genome sequencing, ensuring complete variant overlap, and allowing …

Strain And Strain Rate In Friction Extrusion, Xiao Li, Md Reza-E- Rabby, Anthony Guzman, Glenn Grant, Suveen Mathaudhu, Michah Hinton, Anthony P. Reynolds

Faculty Publications

Friction extrusion is a metal forming process that generates large plastic strains and deformation-induced heating through friction between a rotating die and the material to be extruded. The final deformation state in friction extruded wire has been visualized in previous studies but the distribution and evolution of strain and strain rate inside the solid material have yet to be elucidated. This paper develops an approach that reveals the deformation during the process by visualizing the shape change of the pre-embedded markers in the remnant billet. For the first time, the distribution of steady-state strain and strain rate in friction extrusion …

Health Literacy And People Diagnosed With Mental Illness, Beckie Child

Dissertations and Theses

Health literacy is a well-studied concept that has a large literature base. Yet, little is known about health literacy and people diagnosed with mental illnesses, and even less health literacy research speaks to people diagnosed with mental illness. I used a framework and approach of lived experience of psychiatric diagnosis and psychiatric survivor research to conceptualize and inform the study. It explores health literacy with people diagnosed with mental and physical health diagnoses using a small quantitative survey, focus groups, and an individual interview. The findings suggest that health literacy is a dynamic and complex construct that interacts with the …

Reconceiving The Relationship Between The Built Environment And Walking Behavior: Examining The Samples, Scales, And Methods In Travel Behavior Research, Jaime Pablo Orrego-Oñate

Dissertations and Theses

This dissertation aims to formulate a mechanism for the relationship between the urban form and walking choice that can be consistent across contexts. The motivation is the lack of concordant results in the magnitude of the environmental influence on walking choice in urban areas found in the literature. The dissertation identifies a series of limitations in previous research that could cause mixed results in the magnitudes of the association. This research elaborates an approach to overcome these limitations by proposing a mechanism of the activity density over walking modal share by controlling for trip distance distribution. The aim is an …

The First Record Of Scorpiops Bhutanensis Tikader & Bastawade, 1983 From China, With The First Report Of Its Female (Scorpiones: Scorpiopidae), He-Yu Lv, Zhi-Yong Di

Euscorpius

The first record of Scorpiops bhutanensis Tikader & Bastawade, 1983 from China (Xizang). An emended diagnosis, detailed redescription, and illustrations of the species are provided. Its female is reported here for the first time.

From ‘Homo Economicus’ To ‘Homo Culturalis’: Review Of Irrationally Rational By V. Raghunathan, Milind M. Shrikhande

Markets, Globalization & Development Review

No abstract provided.

John Kuada And Madei Mangori, How To Succeed As An Entrepreneur In Africa: A Practical Guide And Cases (2021), Felix M. Edoho Sr

Markets, Globalization & Development Review

This is a book review of How to Succeed as an Entrepreneur in Africa: A Practical Guide and Cases by Professor John Kuada and Madei Mangori. Despite what is going on about the region, the entrepreneurial success story in African environment is not at all an oxymoron. Across African continent, individuals in several countries, such as Botswana, Ghana, South Africa, and Zimbabwe, have enacted entrepreneurial triumphs, and the success stories are largely untold. Kuada and Mangori now tell the story of successful entrepreneurial ventures across Africa.

Grandchildren Of Ottomans Vs. Children Of Atatürk: A Script On Turkey's Emerging Political Identities Towards 2023, İrem Taştan, Ezgi Karanfil

Markets, Globalization & Development Review

The aim of this script is to take the initiative to open an updated discussion of the ways in which the global ideological market is shaping the collective political identities in the context of contemporary Turkey. We craft two seemingly opposing yet deeply connected political identities, namely the "grandchildren of Ottomans" and the "children of Atatürk", to critically explore the future possibilities for Turkey's contested ideological market.

Does Microcredit Reduce Poverty? An Empirical Exploration In India, Aneel Karnani, Seema Sahai

Markets, Globalization & Development Review

Microcredit has grown dramatically over the last few decades and its supporters have made extravagant promises about its potential impact on reducing poverty. However, much recent research has shown that microcredit has no significant impact on reducing poverty. In this exploratory study we interview 205 clients of for-profit microcredit to better understand the causes of why microcredit has not lived up to its promise. We find the basic problem is that the lending policies of the microcredit organizations are designed to lower the costs and risks, and hence increase the profits of the organization, and are not responsive to the …

Inequality, Economic And Cultural Polarization, And Entrepreneurship Challenges In Emerging Contexts, Nikhilesh Dholakia, Deniz Atik

Markets, Globalization & Development Review

No abstract provided.

Pre-Flight Testing Results Of Multiple Water Propulsion Systems - Resistojet And Ion Thruster For Smallsats, Jun Asakawa, Hiroyuki Koizumi, Kazuya Yaginuma, Yuichi Nakagawa

Small Satellite Conference

This paper described re-flight flight testing results of the miniature water propulsion system combined an ion thruster and resistojet thrusters which is to be demonstrated on-orbit by JAXA’s program named Innovative Satellite Technology Demonstration-3. The unified propulsion system has a huge potential to expand micro/nano-spacecraft utilization and decrease the risk of debris.

Development Of Ascent Propellant Thrusters And Propulsion Systems, Mackenzie Kilcoin, Daniel Cavender, Tomas Hasanof, Michael Zaluki, Tim Mckechnie, Corinne Sedano, Hunter Williams

Small Satellite Conference

Since the 1960s, hydrazine technology has dominated the market of propulsion technology by providing reliable performance on a wide variety of spacecraft. Efforts to replace hydrazine with a higher-performance and safer alternative have engaged numerous emerging technologies in the industry to mature. ASCENT propellant, also known as AF-M315E, is an example of one such green propellant. Initially developed to provide a safer handling environment than hydrazine, ASCENT offers higher overall performance than a hydrazine equivalent by creating more heat during ignition. The next generation of propulsion technology, based on ASCENT propellant, produces a higher impulse and energy density, expanding the …

Design And Testing Of A 100-Mn Class Water Micropropulsion System Using Wire-Fed Magnesium Combustion, Mariko Akiyama, Rucheng Zhang, Hiroyuki Koizumi, Kimiya Komurasaki

Small Satellite Conference

In this study, the brand-new micropropulsion system is introduced to cover the thrust performances shorthanded by the exiting systems. It uses water as an oxidizer and a magnesium wire as a fuel. We constructed the lab-scale model of this micropropulsion system, and conducted several experiments to obtain the reaction rate of magnesium wire in water-vapor flow. Reaction rate showed almost proportional dependence on water-vapor mass flow rate. We constructed the revised version of lab-scale model, and will continue experiments for detailed analysis of combustion.

Twin Ion Engine Demonstration For Small Spacecraft Applications, Michael Tsay, Riley Terhaar, Kyle Emmi, Carl Barcroft

Small Satellite Conference

Two iodine-fueled, second-generation (Gen-2) “BIT-3” gridded RF ion propulsion systems were successfully demonstrated in proximity. The test units feature a host of upgrades from the flight models delivered to Lunar IceCube and LunaH-Map 6U Cube missions onboard NASA’s SLS Artemis 1. Each Gen-2 BIT-3 system is capable of 1.1 mN thrust, 2,150 sec specific impulse and 31.7 kN-sec total impulse, at 75W maximum power input. The twin engines, separated by a mere 6.5 cm, successfully performed simultaneous startup, sequential startup, and throttling, all without noticeable plasma interference. Onboard telemetry confirms that both thruster and cathode pairs operated nominally, and both …

Additively Manufactured Rcs For Small Satellites And Landers, James F. Horton, Joseph A. Helali, Mela H. Fung, Bryan M. Webb, Stephen A. Yows, William S. Brown, Shawn D. Buckley, William F. Sack

Small Satellite Conference

After a fifty year absence, NASA’s return to the lunar surface under the Artemis Program – for long term human exploration and utilization – is driving commercial and academic opportunities for small satellite and small lander platforms (e.g., Commercial Lunar Payload Services program – CLPS). Bipropellant thrusters are a reliable, low risk, and flight proven method for the propulsion and attitude control that is required for complex maneuvers such entry, descent, and landing (EDL) or in-space proximity operations. However, due to the increasingly competitive commercial spaceflight market in the last decade, satellite subsystems must also be affordable to buy their …

A Miniaturized Hydrogen Peroxide/Abs Based Hybrid Propulsion Systems For Cubesats, Tyson K. Smith, Zachary Lewis, Kurt Olsen, Ryan Thibaudeau, Stephen A. Whitmore

Small Satellite Conference

The Space Dynamics Lab is developing a prototype "green" hybrid prototype propulsion system for SmallSats. The system is based on Utah State's patented High Performance Green Hybrid Propulsion (HPGHP) technology. HPGHP leverages unique dielectric breakdown properties of 3D-printed acrylonitrile butadiene styrene (ABS), allowing re-start, stop, and re-ignition. HPGHP works most reliably using gaseous oxygen (GOX) as the oxidizer, but has experienced ignition reliability and latency issues when replaced by high test hydrogen peroxide (HTP). This deficiency results from HTP's high decomposition energy barrier. Tests show that noble metal catalysts like platinum on alumina are effective at decomposing 90% HTP in …

Propellant Management Of Water-Based Microthruster For Suborbital 0g Testing, Katherine Fowee Gasaway, Steven Pugia, Alina Alexeenko, Anthony Cofer

Small Satellite Conference

Size and power are primary limitations on nanosat missions, especially for propulsion, attitude control, or formation flight. New micropropulsion systems that are smaller, lighter, and less power expensive are required for versatile nanosats for cislunar and interplanetary missions. The Film-Evaporation MEMS Tunable Array (FEMTA) is water-based microthruster for CubeSat attitude adjustment that has been developed at Purdue University. FEMTA will provide an attitude control system for microsatellites that uses < 1 W of power in < 0.5 U of volume. The nozzles on FEMTA use heaters at the base of micro-capillary channels to induce film-evaporation, creating a highly controllable, low-power thrust. The novel capillary action thruster also requires a novel liquid 0G propellant management system. The FEMTA 0G propellant management system is a vapor pressure driven pump. It is self-regulating, does not rely on gravity, and does not require complex pressurization systems, making it suitable for microsatellite applications. The system uses a low vapor pressure fluid pressurant to apply a passive, constant deforming pressure upon a diaphragm that separates the pressurant from the propellant. The ratio of specific volume between the pressurant and the propellant is high enough that, as propellant is expended, the diaphragm compresses as the pressurant expands to fill the volume of the spent propellant. As part of the NASA Space Technology Research, Development, Demonstration, and Insertion (REDDI) program, the FEMTA 0G propellant management system is set to be tested during a suborbital Blue Origin New Shepard flight. In preparation for a 2023 launch, an experiment to test the propellant management system has been designed and built and engineering tests have been performed.

Real-Time Relay Of Small Satellite Remote Sensing Data To Tactical Military Operators, Robert Zitz, James Schwenke, Rob Singh

Small Satellite Conference

A Medium Earth Orbit (MEO) constellation of high bandwidth optical and RF relay satellites is urgently needed to provide real-time continuous tasking uplink and data downlink from the growing constellations of commercial remote sensing satellites. Tactical military operators have a need to establish communications links to these commercial assets, from commercial CONUS ground stations or directly to deployed ground terminals, when and where they need it. This level of access adds significant risk mitigation against adversary threats to foreign ground stations and data processing nodes in combat and can make the concept of a hybrid architecture combining government satellites and …

Development Of University-Friendly Cubesat Bus And Ground Station Architecture Using Software-Defined Radios, Jin S. Kang

Small Satellite Conference

The goal of the research and development presented in this paper is to introduce a CubeSat bus and ground station architecture that is made to be much more approachable to schools and universities. The three main pillars of the effort are low-cost, maintaining flexibility, and lowering the bar of entry. The presented CubeSat bus includes PyCubed board which houses most of the core satellite bus components on a single board. The board can handle main processing, data storage, UHF radio communication, telemetry sensors, and power management. This UHF radio is paired with a software-defined radio (SDR) that serves as the …

System Architecture For A Cubesat Dte Laser Communication System, Pj Du Plooy, Gilles Ackaert, G. Witvoet, W. Crowcombe

Small Satellite Conference

Small satellites and CubeSats are playing an increasingly larger role in technology demonstrations, research, and obtaining data for commercial use from space. As these use cases and applications for CubeSats increase and expand the need to get fast, secure and reliable access to the data gathered by the payloads on these spacecraft also increases. To support these developments AAC Hyperion together with TNO has developed a down-to-earth laser communication module for small satellites and CubeSats with a downlink capability of 1 Gbit/s, namely CubeCAT.

One of the challenges that needed to be solved to ensure success was how to deal …

Thermal Modeling Of Femta Micropropulsion System For Cubesat Attitude Control, Florian Alexander Hoeft, Steven Pugia, Alina Alexeenko

Small Satellite Conference

Nano and pico-class satellite platforms such as 1U CubeSats, PocketQubes, and ThinSats introduce unique power and volume constraints on propulsion systems. The Film-Evaporation MEMS Tunable Array(FEMTA) microthruster is one compact, low-power technology that is well suited for these applications. FEMTA thrusters are microfabricated on 1 cm x 1 cm x 1 mm silicon and glass chips. Each chip contains an array of micrometer-scale capillaries which are electrically heated to vaporize the liquid propellant and generate controlled thrust. Sixth generation FEMTA devices have been demonstrated to produce greater than 300 microNewton of thrust per 1 Watt of electrical power at 90 …

Design And Optimization Of An Autonomous Constellation Of Small-Satellites For Leo And Beyond, Mohammed Irfan Rashed, Hyochoong Bang

Small Satellite Conference

The speedy data reception with useful applications such as disaster management remains to be need of the hour. This paper addresses the major concerns relating to deployment and control of the larger small satellite (mainly cubesats) constellations in LEO by determining their relative position and velocity errors under certain acceptable limits with collision avoidance techniques. The article will also discuss the importance of Inter-satellite link to significantly to strengthen the satellite tracking and their data sharing speeds. The issue of optimal dispatch of the satellites by optimizing the constellation size is detailed though observing and controlling the orbits using a …

Test And Evaluation Of Grissom-1 Cubesat Communication Subsystem, Michael J. Bittle, Andrew S. Keys

Small Satellite Conference

The Grissom-1 mission (GM1), slated to launch in September 2022, is the first in a series of 6-Unit CubeSat satellites built and operated by the Air Force Institute of Technology’s (AFIT’s) Center for Space Research and Assurance (CSRA). Mission success for GM1 depends on a comprehensive campaign of testing and assessment to confirm the components, design, and assembly of all systems and subsystems within the satellite. This paper specifically focuses on the testing and analysis of all communication links between the spacecraft, the ground system, and the Satellite Operations Center (SOC) being hosted at the Air Force Instituteof Technology at …

Design Proposal And Realization Of An Academic-Nanosat "Pedago-Sat" Platform For Aerospace Training, Boutte Aissa, Belaidi El Yazid

Small Satellite Conference

Through this project, we try to promote the local aerospace knowledge by proposing a new kind of cooperation between the algerian universities and the ALgerian Space Agency (ASAL). The adopted method consists in developing an engineering training platform of a Nano-satellite (Open-source) and preparing functional and practical test courses to allow to the students and trainees the access to various knowledge related to the development and integration of satellites. The development plan granted to this platform (PEDAGO-SAT) is 36 months. At first milestone, a preliminary design realization of prototype are done, covering the certain equipment and sub-systems. The mechanical structure …

Development Of A Modular Propulsion System For Use In A Deep Space Hybrid Architecture, Stephen Mauthe, Bradley Hoover, James Brent, Noah Szczepanik

Small Satellite Conference

With recent and upcoming initiatives to revisit the moon and to begin planning for sending humans to Mars, the role of small spacecraft to facilitate and compliment these types of missions continues to grow. However, unlike low-Earth orbit (LEO), where small satellites have historically found their highest utilization, venturing further away from Earth and the more benign space environment it provides can prove to be a challenge for spacecraft designers. Factors can become difficult to design for, such as expected temperature ranges, power generation and radiation effects. At the same time, the objectives that small spacecraft are attempting to accomplish …

Flight And Direct To Earth/Space Relay Communication System Architecture For Gsfc Cubesat Missions, Ethan Abele, Serhat Altunc, Obadiah Kegege, Kaitlyn Ryder, Behnam Azimi, Michael Campola, Kevin Lynaugh, Gianfranco Barnaba, Sabit Ekin, John O'Hara

Small Satellite Conference

The CubeSat platform is finding increasing use in space science applications due to its low cost and comparative ease of launch. It is becoming a key scientific discovery tool in low Earth orbit (LEO) and beyond, including geosynchronous equatorial orbit (GEO), the Lagrange Points, Lunar missions, and more. The increasing complexity of these missions and their scientific goals must be supported by equal advancements in communications technology. Higher data rates and greater reliability are required every year. However, the reduced Size, Weight, and Power (SWaP) constraints of CubeSat platforms introduce unique challenges in the area of satellite communications. There is …

Angels: Opening The Door Of The French Newspace, Laurène Gillot, Dominique Delacroix, Romain Mathieu, Christian Rossiquet, Thibéry Cussac, Dries Caluwaerts, Corinne Fournigault

Small Satellite Conference

In December 2019, ANGELS, the first nanosatellite designed and developed by French industry, supported by the French Space Agency, CNES, was launched from Kourou. Development and qualification of the satellite were achieved in two and a half years: quite a challenge!

The ANGELS demonstration mission was set up as a co-funded partnership between CNES and Hemeria in order both to validate new technologies and to promote the “new space” approach. Thales Alenia Space & Syrlinks led the team in charge of the Argos Néo instrument payload. The data collected for two years now show that the chosen compromise was the …

Reusable Electron: Analysis Of Progress Toward The World's First Reusable Commercial Small Rocket, Lars Hoffman, Murielle Baker, Shane Glynn, Matt Darley, Peter Beck

Small Satellite Conference

Leading end-to-end space company Rocket Lab has significantly advanced its rocket reusability program over the past 12 months, bringing the Electron launch vehicle closer to becoming the world’s first reusable commercial orbital class small rocket. Applying the concept of a circular economy to rocketry, Rocket Lab’s reusability of Electron is expected to produce benefits to the space industry including reduced environmental pressure, innovation in rocket reuse technology, better sustainability of material supply, and lower launch costs to the burgeoning small satellite market.

Rocket Lab’s concept of operations for rocket recovery includes the capture of a returning Electron first stage mid-air …

Ops-Sat Leop And Commissioning: Running A Nanosatellite Project In A Space Agency Context, David Evans, Georges Labrèche, Tom Mladenov, Dominik Marszk, Vladimir Zelenevskiy, Vasundhara Shiradhonkar

Small Satellite Conference

OPS-SAT is a 3U CubeSat launched by the European Space Agency (ESA) on December 18, 2019. It is the first nanosatellite to be directly owned and operated by ESA. The spacecraft is a flying platform that is easily accessible to European industry, institutions, and individuals, enabling rapid prototyping, testing, and validation of their software and firmware experiments in space at no cost and no bureaucracy. The spacecraft is equipped with a full set of sensors and actuators including a camera, GNSS, star tracker, reaction wheels, high speed X band and S band communication, laser receiver, software defined radio receiver, and …

Remote Sensing Experiments Using The Rogue-Alpha,Beta Cubesats As A Constellation: High Frame Rate Environmental Observations From Agile, Taskable, Infrared And Visible Sensors In Low Earth Orbit, Dee W. Pack, Pradeep Thiyanaratnam, Tom Freeze, Brian S. Hardy, John R. Santiago, David Pietrowski, Jon C. Mauerhan, Patrick D. Johnson, Paul F. Zittel, Cameron R. Purcell

Small Satellite Conference

The Aerospace Corporation’s Rogue-alpha,beta program built and launched two 3-Unit CubeSats in 18-months, each equipped with modified commercial infrared camera payloads, visible context cameras, laser communications and precision pointing capabilities. Launched on November 2, 2019, the two spacecraft (Rogue-alpha and beta) were boosted and released from the International Space Station Cygnus NG-12 robotic resupply spacecraft on January 31, 2020 into a circular 460-km, 52° inclined orbit. The primary Rogue IR sensor is a 1.4-micron band, 640x512 pixel, 28° field of view, InGaAs short wavelength infrared (SWIR) camera. It is accompanied by a panchromatic, 10-megapixel, 37° field of view visible context …