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Impacts of 4R Nitrogen Management and Water Optimization on Soil Health
Get PDFFarmers in Utah and Idaho are facing growing challenges due to high fertilizer costs, limited irrigation water, and pressure to improve long-term soil health. To better understand current practices and grower attitudes, a survey was conducted in 2020 targeting 5,000 producers of small grains, corn, and potatoes. Although the response rate was low, 146 growers representing over 25,000 hectares of cropland participated. Survey results showed that most growers are open to improving nitrogen and irrigation practices and care about their soil health, even if not all are fully using 4R or precision agriculture methods.
This thesis includes two field studies aimed at addressing those needs. The first study tested 4R nitrogen strategies, right rate, source, timing, and placement across cherry orchards, silage corn, potato, and wheat systems at four locations in Utah and Idaho from 2020 to 2023. Soil samples were analyzed for residual nitrate, soil respiration, ACE protein, aggregate stability, total nitrogen, and total carbon. Results showed that site-specific nitrogen management could reduce nitrate leaching and improve soil biological activity without harming soil productivity. Positive results were especially pronounced in Kaysville and Kimberly, where fertilizer timing, rate, and placement had the most significant effects. The second study evaluated how deficit irrigation combined with land management practices (no-tillage, cover cropping, and drought-tolerant hybrids) impacted soil health and water infiltration across three Utah sites between 2019 and 2023. A split-plot design tested full and 50% irrigation rates across five treatments. Results showed that the effects of deficit irrigation varied by site and soil type. In drier areas like Cedar City, reduced irrigation led to declines in biological soil health indicators, while other locations maintained or improved soil function when combined with conservation practices.
Together, these studies show that integrating 4R nutrient strategies with water-saving practices can support healthier soils and more efficient resource use. However, successful outcomes depend on matching practices to local conditions
Ecology and Management of Forest Grouse: Breeding Acoustic Monitoring, Spatial Behavior, And Harvest
Get PDFForest grouse are difficult to study and manage in the Intermountain West because they live in remote, rugged areas and do not gather at predictable display sites like other grouse species. From 2023 to 2025, I studied two species, dusky grouse (Dendragapus obscurus) and ruffed grouse (Bonasa umbellus), to test new survey tools, track their seasonal movements, and evaluate hunting impacts. First, I tested whether small audio recording devices placed in the forest could minimize labor needed for spring breeding surveys. To do this, I conducted traditional surveys with human observers at the same time and locations as the recording devices in Utah’s Bear River Range. The devices detected more grouse overall and produced similar results to in-person counts, especially for ruffed grouse. This method could make it easier for wildlife agencies to monitor grouse over large areas with fewer staff. I also trained and tested sound identification models that can be used in future research and monitoring. Next, I tracked the movements of two dusky grouse populations using GPS trackers. Birds in Nevada used larger areas than those in Utah, likely due to lower population densities and harsher conditions. Both populations showed strong loyalty to the same breeding and wintering areas each year. In Utah, I studied the types of forest habitat used during winter and found that dusky grouse preferred mature forests with taller trees and moderate tree cover. These findings help fill important gaps in what we know about dusky grouse and can guide future forest management. Lastly, I looked at hunting effects by marking birds with leg bands and collecting wings from harvested birds in the Bear River Range. The number of wings submitted doubled in 2024, suggesting increased hunting. More harvested dusky grouse were female, and fewer young ruffed grouse were collected in 2024, indicating a poor breeding year. Many hunters appeared to have trouble identifying the two species correctly. This research provides new tools and information that can help wildlife managers better understand, monitor, and conserve forest grouse in the West
Understanding Salt Stress in Watermelon: Impacts on Plant Performance, Adaptive Solutions, and Future Prospects
Get PDFSoil salinity stress, intensified by extreme weather patterns, significantly threatens global watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] production. Watermelon, a moderately salt-sensitive crop, exhibits reduced germination, stunted growth, and impaired fruit yield and quality under saline conditions. As freshwater resources decline and agriculture’s dependency on irrigation leads to soil salinization, we need sustainable mitigation strategies for food security. Recent advances highlight the potential of using salt-tolerant rootstocks and breeding salt-resistant watermelon varieties as long-term genetic solutions for salinity. Conversely, agronomic interventions such as drip irrigation and soil amendments provide practical, short-term strategies to mitigate the impact of salt stress. Biostimulants represent another tool that imparts salinity tolerance in watermelon. Plant growth-promoting microbes (PGPMs) have emerged as promising biological tools to enhance watermelon tolerance to salt stress. PGPMs are an emerging tool for mitigating salinity stress; however, their potential in watermelon has not been fully explored. Nanobiochar and nanoparticles are another unexplored tool for addressing salinity stress. This review highlights the intricate relationship between soil salinity and watermelon production in a unique manner. It explores the various mitigation strategies, emphasizing the potential of PGPM as eco-friendly bio-inoculants for sustainable watermelon management in salt-affected soils
Deployable Diffractive Optical Elements for Small Satellite LiDAR Missions
Get PDFSPECIES (Smart Polyimide Expandable Collector to enable Investigations for Earth Science) is a NASA Earth Science Technology Office (ESTO) project that explores the use of a deployable diffractive optical element (DOE) in a space-based lidar instrument for a 12–24U CubeSat operating in low Earth orbit (LEO). The DOE, a 0.6-meter hybrid multi-level Fresnel zone plate, is made using a tessellation of hexagonal molds, each with a unique number of diffractive levels. It is stowed for launch and deployed on orbit using a 3 meter long extendible boom, which positions the optic at the correct distance from the spacecraft, while guy wires provide tensioning to maintain a flat profile. This approach leverages the weight and cost advantages of DOEs over traditional optics of comparable size, making them a promising option for small satellite platforms.
The project examines key challenges in deploying and operating such an optic, including the identification of supporting optical and spacecraft systems and modeling the effects of mechanically and thermally induced deformations, up to millimeters in size, on lidar performance. A custom optical model is used to propagate the beam through the deformed DOE and evaluate key performance metrics, including point spread function spot size and lidar signal to noise ratio. Simulations show that despite the presence of moderate deformations, the proposed DOE architecture maintains a compact enough PSF (80% energy in a 1 mm radius), and a cloud-targeting lidar SNR within a factor of three of CALIOP—a heritage lidar mission using traditional reflective optics—while offering significant advantages in mass and receiver aperture size. By quantifying these effects, this work aims to establish the feasibility of using large-format, lightweight DOEs in space-based lidar systems
A Ka Band High Data Rate Transmitter for LEO Satellites Design and System Simulation
Get PDFThis paper addresses the design of a high-throughput Ka-band transmitter for LEO satellites. This article particularly focuses on RF and microwave subsystems and system simulation.
The purpose of this transmitter (named KaLLISTO) is to operate the downlink from a LEO satellite to a ground station. High data rates are required to meet the expressed demand from satellite operators to enable much more data volume downlink. The equipment is the latest state-of-the-art qualified COTS based design. This design is perfectly adapted to New-Space programs, where cost effectiveness, performance and reliability are key factors. The allocated band goes from 25.5 to 27GHz Concerning the waveform the DVB-S2 standard is used to obtain flexibility for the modulation (QPSK, 8PSK, 16APSK, 32APSK) and for the coding rate. Traditionally, the X band from 8.025 to 8.4 GHz is used to ensure the downlink but the available bandwidth is relatively limited, only 375MHz. Also, it is important to know that X Band is starting to become saturated due to an increased number of users. This explains the growing interest in Ka Band.
The first part of the paper will present an overview of the transmitter architecture based on direct IQ up-conversion. We continue to present the downlink RF link budget in X and in Ka Bands between the transmitter embedded in the satellite in LEO orbit and the ground station. The objective is to highlight the RF key parameters to optimize the use of the highest modulation order as possible thanks to the DVB-S2 standard (QPSK, 8PSK, 16APSK and 32APSK). A comparison between X-Band and Ka-Band on the total bytes transferred during one satellite pass is carried out.
To optimize the design of SOE (Satellite-Onboard Electronics ex-Syrlinks) radio frequency transmitters (in X and Ka-band) we set up a system simulation based on the well-known Complex Envelope technique to modelize an RF signal. This simulation approach makes it possible to know the contribution of each transmitter stage (baseband, RF synthesizer, IQ Mixer, power amplifier, filtering, etc.) to the quality of the transmitted RF signal. The quality of the in-band RF signal is characterized by the EVM (Error Vector Magnitude) extracted from the complex constellation signal.
We will highlight the statistical characteristics of the modulated signals with CCDF curves for the four modulation schemes of the DVB-S2 standard. A comparison between simulations and measurement on spectrums, ACPR (Adjacent Channel Power Ratio) and EVM at different transmitter stage (Baseband, IQ modulator output, RF output including power amplifier and filtering) will also be described. Finally, the paper will present the consolidated relationship between EVM and Bit Error Rate (BER). This simulation work prepares the introduction of predistortion techniques in our transmitters
Integrating Launch Vehicles and Satellite Communications: Interstellar\u27s Advancements With Toyota\u27s Expertise
Get PDFInterstellar Technologies, a private Japanese aerospace company, is developing a vertically integrated space infrastructure combining orbital-class launch vehicles and advanced satellite communications. Its rocket, ZERO, is a two-stage vehicle designed and manufactured entirely in Japan. To scale production, Interstellar has partnered with Woven by Toyota, applying automotive manufacturing principles to rocket production. This collaboration, backed by a ¥7 billion (~$44 million USD) investment, aims to create Japan’s first mass-producible launch platform.
In parallel, Interstellar is developing direct-to-device broadband communication satellites and has been selected for JAXA’s formation flight program, working with top universities to develop femto-satellite constellations. By integrating launch and satellite capabilities, Interstellar offers a scalable, cost-effective model for sustainable space access in Japan and across the Asia-Pacific region
Aerogel-Enhanced E-Ink Particle Detector (AEPD) For Thermospheric Studies
Get PDFCurrent SmallSat particle detectors suffer from high power consumption ( \u3e 5W) and poor spatial resolution ( ≥ 1mm), limiting thermospheric research capabilities. The Aerogel-Enhanced E-Ink Particle Detector (AEPD) ideation is intended to revolutionize space instrumentation by integrating radiation-tolerant aerogel ( ≤ 3 mg/cm3) with modified E-Ink display technology. This breakthrough if valid can achieve close to 100mW operation with ≤ 200μm resolution, a 50x power improvement and 5x resolution enhancement. The aerogel\u27s graded nanostructure provides 40% capture efficiency gains, while E-Ink layers enable 12-hour persistent visualization without power. Laboratory validation demonstrates 92% particle classification accuracy and linear energy response (R2 = 0.98). AEPD-1 SmallSat deployment if successful will democratize space weather monitoring through ultra-low-power constellation networks
Gram-Scale ChipSat Spacecraft for Light Sailing in LEO
Get PDFCornell University’s Alpha mission is a 1U CubeSat that deploys a retroreflective free-flying light sail in LEO. Mounted to the sail, and serving as its flight computers, are four ChipSats –gram-scale spacecraft assembled onto a single palm-sized PCB. These satellites collect and downlink data on the sail’s orbital position and attitude kinematics, communicating directly with low-cost ground stations around the globe. This paper introduces the ChipSat developed specifically for the Alpha mission launching in 2025. The new femto-satellite builds on previous-generation designs with a significant revamp of the RF communications. This paper provides an overview of the as-flown ChipSat design and outlines significant test milestones that validated it for flight. Light sail integration, flight software architecture, and the ground segment are also discussed
Women and STEM − A 2025 Update
No full textAlthough the term STEM (science, technology, engineering and math) was coined in 2001 by Judith A. Ramaley of the National Science Foundation and had been used informally in the previous decade,1 the push for STEM in the US began in the 1950s with Russia launching Sputnik and the US subsequently pouring billions of dollars into educating students to ensure the nation became a technological global power. However, the gender gap in STEM fields today reduces the innovation that could be achieved with more unique perspectives contributing to the field. Closing the gender gap in STEM is vital because scientific progress relies on the unique solutions that arise from diverse perspectives, and the innovation necessary to address the problems of today and tomorrow requires these different perspectives, including those of women.2 Having more women in STEM will also help close the gender pay gap and create more inclusive products and services.3
Utah lags the US for women’s involvement in STEM fields, with higher occupational segregation (also known as gender disparity) in STEM fields in the state than in the US.4 Of particular concern have been the issues of STEM education and barriers women face to entering and staying in the fields. Since the UWLP’s last snapshot on the topic in 2022, Utah has done more to empower girls and women in STEM, and the percentage of women in STEM fields has increased, although there remains much progress to be made. This snapshot updates and expands on the data in that report, including: The state of STEM in Utah, Current STEM employment and education data, STEM education, Barriers to women\u27s involvement in STEM, Efforts to increase participation, and What Utahns can do to enact change in these fields
KorucuSAT: A Student-Led CubeSat Mission Investigating Solar-Ionospheric Interactions and Promoting STEM Education
No full textThe Astronomy Society of Fulton Science Academy (ASFSA) is developing KorucuSAT, a 3U CubeSat designed to both inspire K–12 students through hands-on aerospace education and investigate how soft X-ray solar radiation impacts the Earth\u27s F2 ionospheric layer. The satellite carries a Langmuir probe, three-axis magnetometer, and soft X-ray detector to correlate solar radiation with plasma parameters and geomagnetic activity, data critical to understanding disruptions in GNSS, HF communication, and radar systems. In parallel with its science goals, KorucuSAT is a platform for educational outreach, including classroom workshops, MIT Beaver Works curriculum integration, and a FlatSat-based Python coding challenge. The mission also partners with local schools and institutions such as the University of Georgia SSRL, ensuring the program’s longevity and impact beyond launch. KorucuSAT has undergone thorough technical and merit reviews by professionals from NASA JPL, MIT, and university partners