Reverse osmosis (RO) is one of several methods for water desalination. Over the years the energy efficiency of these systems have increased greatly and many variants of RO have emerged. The method that provides the most energy efficient system is batch RO. Batch RO provides the ability to recycle the retentate that is produced until it reaches a concentration where it can no longer be used. Additionally, batch RO can keep the pressure and osmotic pressure of the system balanced to prevent the need of external energy recovery devices. One challenge about this system is the supersaturation levels which can occur in the recycled retentate. With a high enough concentration nucleation will begin to occur causing scaling in the membrane reducing system efficiency. In this study, a 15-hour batch cycle is observed to analyze the concentration of calcium sulfate at the membrane, the saturation index of gypsum, and the potential induction times over the trial. After the sixth hour in the trial, a batch developed a concentration at the membrane of about 10 mM higher than any other batch creating a supersaturation solution with an induction time near the length of time the batch ran for. Subsequent batches revealed that each took almost twice as long to complete, suggesting that scaling of the membrane had occurred during the batch with the highest saturation index. These results help explain why: concentration at the membrane, saturation index, and induction times are important metrics to consider to run a batch RO system more efficiently.

In March 2020, the Federal Communications Commission (FCC) initiated a processing round calling for additional applications for non-geostationary satellite orbit (NGSO) fixed-satellite service (FSS) operations in Ka-band. Satellite operators submitted descriptions of their planned constellations and provided proof that their systems would comply with interference limits set by the FCC and the International Telecommunications Union (ITU). All ten companies in this processing round provided power flux density (PFD) compliance calculations. Three companies optionally submitted interference-to-noise (I/N) compliance calculations: Telesat, SpaceX, and OneWeb. This paper documents a standardized process to calculate I/N and analyzes I/N compliance for these three companies. I/N analyses consist of static analyses, which considers the worst-case interference scenario, and dynamic analyses, which computes the interference over time. In ITU-R F.1495, the long-term I/N limits are defined to not exceed -10 dB for greater than 20% of the year, requiring dynamic analyses to prove compliance. Static I/N analysis is calculated in this paper, which allows for verification of compliance with the long-term dynamic -10 dB limit in the worst-case scenario. Dynamic I/N analyses are required to verify compliance fully and will be addressed in future work. This study shows that Telesat, OneWeb, and all SpaceX operations at a minimum elevation angle of 25° complied with I/N long-term dynamic limits of -10 dB, but SpaceX operations at altitudes of 360 km and 373 km with a minimum elevation angle of 5° exceeded I/N limits in the worst-case scenario.

Batch reverse osmosis is a unique process that uses standard equipment to recover water from scaling-prone reverse osmosis (RO) concentrate. Batch RO avoids scaling by operating in cycles that are too short for scalants to nucleate. Batch RO can efficiently reduce inland desalination plants’ concentrate disposal costs while recovering potable water. We have demonstrated batch RO at the pilot scale as part of the US Bureau of Reclamation’s More Water Less Concentrate Challenge. The pilot system demonstrated more than 80% water recovery from RO brine for less than 2.5 kWh/m3. By leveraging batch RO’s cyclical operation and demonstrating its efficacy with the Yuma Desalting Plant’s challenging RO brine, we hope to expand the capabilities of RO for low-energy, high-recovery desalination.

Drones are often equipped with shock-absorbing rigid structures intended for landing or absorbing impact of crashes. While the landing gear that manufacturers supply does protect the drone from damage, these rigid structures work best on flat surfaces. We investigate the use of compliant structures inspired by origami for landing gear and bumper systems for drones. Compliant structures absorb more energy than rigid structures and are adaptable to varied terrain. Two of our main goals were to make the designs easy to manufacture/reproduce, and to reduce the weight of the prototypes to minimally affect drone flight performance. The majority of our designs are targeted towards the landing system of the drone. In our investigation, we explore variations of origami folds and how these variations affect damage from compressive impact.

There has been a rise in demand for fish products in the US, leading to the need for more offshore aquaculture farms. These farms have been a source of controversy for many years. While some point to them as sustainable alternatives to land farms, there has been an outcry that aquaculture is bad for the oceanic ecosystem. Despite these arguments, not enough data exist to support either claim, particularly as to how damaging aquaculture is to the underwater environment. In response to this, we are developing a deployable, autonomous aquaculture profiler. The profiler is designed to be handled by two people, and can dive to varied depths, collect data, and return to the surface along a mooring line. It shows promise as a solution to the controversy surrounding fish farms, as it can help in data collection concerning the environmental impact. Additionally, it can act to monitor fish health on established aquaculture sites for more general use.

LiDAR technology can accurately generate a 3D representation of the environment which creates numerous opportunities for improving assistive technology for blind and visually impaired individuals. Unfortunately, LiDAR is expensive and only available in high-end mobile devices, including the iPhone 12 and 13 Pro, making assistive technology inaccessible to the majority of users. Software LiDAR aims to imitate the capabilities of LiDAR by integrating the output of MiDaS, a neural network for depth estimation,and Apple’s ARKit to bridge the gap in technology and make assistive technology more accessible to users. Software LiDAR was created and benchmarked against LiDAR, and found to be fairly accurate, especially after removing failure cases. Moreover, codesigners expressed a desire for using the MiDaS depth data to create object detection, showing its potential in assistive technology and motivating the future development of software LiDAR.

Before the 1950’s, the Air Force believed in the ‘average man’ [4]. The ‘average man’ was believed to be the average in human body data as a way to oversimplify the variability in a population of pilot bodies. This was to simplify the design for a cockpit to fit everyone since it would fit the ‘average man.’ It was only until further investigation by Gilbert Daniels revealed that out of the thousands of Air Force pilots (over 4,000 pilots), no one was average in all dimensions of a pilot. Daniels quoted that “‘the average man’ is a misleading and illusory concept as a basis for design criteria,” illustrating the importance of handling variability in the real world and the consequences of only using a single value (the mean) to represent a distribution [4]. However, this is not the only example of variability negatively affecting the effectiveness of designs, and furthermore, this is not a widely known study. Despite the results of this study, there is a lack of research regarding how engineers handle variability. Many industries rely on single values (like the mean) when doing engineering design work. This flattens real world variability, and opens up the potential to design shortfalls and probability of failure. For example, if an engineer were building a structural system out of an aluminum alloy, they might use a mean strength value of that alloy when doing calculations for the design. Because real world materials have variability, meaning the samples will exhibit a range of different strength value, this design approach could lead to mechanical failure if the sample used in the construction falls below the mean strength used in the design. This is why it is important that engineers are given adequate tools and knowledge on how to approach real world variability. In this study, we conducted interviews with engineers to understand how they approach real world variability. The goal of this study is to better understand how engineers reason under uncertainty, and to provide more baseline research that will help us to better educate engineers on how to approach variability.

Makeup Assist is an iOS app that improves the experience of applying makeup for individuals who are blind or visually impaired. Most efforts in developing assistive technology have concentrated on making necessary tasks more self-reliant. This app strives to create more ways through which blind and visually impaired people can freely express themselves and experience independence beyond just basic tasks. With Apple’s Face Tracking technologies, voice overs capabilities, and Firebase’s cloud database, the Makeup Assist app provides real-time assistance and feedback to achieve just that.

From 2015 to 2021, the FCC held eleven auctions, an unprecedented amount [1]. Analysis and comparison of these auctions provide a unique opportunity to quantify bidding trends and auction results based on metrics like frequency, geographic factors, and population data.

This paper primarily assesses Auction 107 (C-Band) data and compares the findings with those of Auctions 1000 (600 MHz Band), 101 (28 GHz Band), 102 (24 GHz Band), and 103 (Upper 37, 39, and 47 GHz Bands), and 105 (CBRS Band).

I explored many different ceramic techniques including slab-building, coil-building, and wheel throwing. For my final exhibition, I wanted to continue on with a previous final project that I had for Tell the Story that was centered around integrating Asian snack designs into everyday objects.

For my AHS Capstone, I wrote a paper on policy changes that would be necessary in order to promote satellite servicing in space and help promote a more sustainable space environment. This infographic summarizes the technology and policies in the satellite servicing field.

This article is the final version of my 2023 AHS Capstone work. It is a 10 page paper about the ethics of robots especially the ones that are used in the workforce.

The project focused on creating accessible video game designs for individuals who experience limitations in their physical movements. Through research on requirements and existing approaches, this project aims to provide enjoyable gaming designs that are inclusive and accessible to all players, regardless of their physical abilities.

For my AHS Capstone I decided to contextualize how Dante's Divine Comedy, and in particular Dante's Inferno, influenced different parts of society: such as the Italian Language, the views on the Afterlife, and different forms of classical and modern media.

For my AHS Capstone, I wanted to create a new fantasy world and explore some family and societal dynamics. I wanted to do it through something other than exposition, so I created a character, Ishya, a 25-year-old traveller, to explore the setting.

The reflection game created by Regan Mah in the AHS Capstone class of Spring 2023. A set of prompts that allow players to reflect upon various life experiences.

Microbial communities are an important cornerstone of all ecosystems. By studying their interactions and the way they respond to environmental changes we can better understand which factors contribute to the ability of the community to function. Previous experiments were conducted to gather data on how microbial community composition changes over time of a nutrient perturbation. After collecting this data, the microbial community composition was determined by sequencing of the 16SsrDNA gene. Being able to analyze these datasets of community composition, is where we are able to gain the most understanding of the significance of the community. There are main ways to look at these communities but the main three are the statistical approach, network analysis, and linear systems modeling. Each of these provides a different lens to look at datasets which can be used to give context to the various trends in the data. Being able to understand how to use each of these methods and determine which is the most useful for any given dataset is an important part of this research.

Article 22 of the International Telecommunications Union (ITU)'s Radio Regulations, Equivalent Power Flux Density (EPFD) is defined to ensure protection from harmful interference from non-geostationary (NGSO) systems into geostationary (GSO) satellites or earth stations. EPFD depends on the power flux density amplified or attenuated by the antenna gains of the NGSO and victim GSO systems. This occurs when an NGSO satellite transmits towards their system's ES, and some of the NGSO's transmitted power and causes interference to the GSO ES. EPFD calculations are performed in three directions: down, up, and intersatellite. The paper focuses on the EPFDdown algorithm and its applications in interference regulations and radio astronomy services (RAS), which tend to be more susceptible to unwanted emissions from other systems. In order to protect RAS, a new set of EPFD limits was established. To ensure that RAS is protected, the ITU Radiocommunication Sector restricts harmful interference. EPFDdown is defined as the EPFD from the NGSO satellite into the victim GSO earth station (ES), and accounts for the gain pattern of both NGSO satellite and the GSO victim ES in a particular orbital geometry and frequency band. In terms of RAS, RAS telescope sites on Earth are victim ES. To help prevent Article 22 limit exceedances, the ITU's Radiocommunication Sector (ITU-R) defined Recommendation S.1503 to provide guidance for satellite operators developing software to evaluate EPFD limits. This study focuses on implementing the EPFD-down algorithm in ITU-R S.1503 to analyze EPFDdown. With the EPFD validation process, NGSO systems can ensure that incumbent and planned GSO networks can operate without harmful interference, reducing data loss caused by interference from NGSO satellites. By going through each step of the EPFD validation process to validate Mangata's EPFDdown showing, this paper aims to make the complex EPFDdown algorithm more accessible to companies who are operating satellite systems.

Clew Maps is an update to a preexisting iOS App for indoor navigation called Clew. Presently, blind and visually impaired (BVI) individuals struggle to navigate unfamiliar spaces, and often have to rely on navigation instructions from a sighted guide. Clew Maps introduces a cloud database that can store pre-recorded routes that users can navigate along in an App Clip experience. This means that even non-Clew users can utilize the navigation tool without downloading the app, and that routes can be navigated by an individual without them having to walk along the route to record it ahead of time. Clew Maps robustly anchors the device utilizing ARKit’s ARImageAnchors; however, more work is required to better understand the potential use cases and address potential pain points for BVI individuals, such as route discovery and aligning to image anchors.

Research was done on actuators for a soft robotic glove that could assist children with cerebral palsy with at-home hand physical therapy. Materials in the construction of fabric-based soft pneumatic actuators were evaluated for this purpose. Three different bladder types (TPE impulse sealed bladders, condoms, and modeling balloons) were tested. The straightening and bending force each actuator could produce as well as the shape the actuator formed when unrestrained were analyzed. The results indicated that condoms and modeling balloons are superior to TPE bladders for the use as bending bladders. All bladder types performed well as straightening bladders so any could be chosen depending on the desired quantitative values such as the straightening force and force-to-pressure relationship. Further research is needed into the durability of each bladder type and into attachment methods of each bladder to prevent air leaking.

Clew Maps reimagines Clew as an app that crowdsources routes for indoor navigation and repurposes the existing backend code base to better serve this purpose by alleviating the pain points inherent to the current route-sharing mode of use. By implementing image anchoring to improve the robustness of the anchoring and alignment process, and by using a cloud database for route storage along with a new user interface (UI) to address the limitations of sharing routes in Clew, Clew Maps makes independent travel in unfamiliar public spaces more accessible for people with blindness and visual impairments (B/VI).

The RoboTuna is a robotic fish that will be able to collect samples from marine wildlife and allow us to better understand the oceanic ecosystem and the behavior of underwater creatures. This biomimetic robot will be able to get closer to fish and other creatures in their natural habitat than a person ordinarily could, and therefore will give new insights into how the underwater world is changing. Many of the RoboTuna’s pieces need to be flexible and waterproof, so casting and molding will be necessary to create them. The focus of this research was on fabricating a fin and air bladders for the RoboTuna, which included experimenting with different kinds of silicone rubber and urethane plastic. Existing soft robotic actuators have been extremely helpful to gain insight on how to move these parts without mechanical mechanisms. Shape memory alloys allow for simpler fin movement actuation instead of having to rely on a bulky motor. The same goes for moving the tail via air bladders, a kind of fluidic elastomer actuator. The differences between different kinds of silicones and how each material and molding method affected the fabricated parts are shown through flexibility and strength data. The information here can help future researchers determine what materials would be best for various parts of the RoboTuna and understand their options for soft robotic actuators.

There are long-standing examples of how engineers’ education in probability and statistics has not been sufficient. This work presents a novel theoretical framework to help teach and study statistical variability. Using this framework, we developed an interview guide and deductive coding scheme to use in interviews with engineering students. Early results from these interviews support our initial hypothesis of a slight induced variability bias.

Computing has a history of perpetuating injustices, a pattern that has only seemed to grow worse over recent years. These injustices are a direct result of computing's epistemic values and practices, which suggests the need for computing to adopt alternative epistemic values and practices, including sociopolitical awareness, reflexivity, humility, and an explicit commitment to justice. These are the central values of feminism, but while scholars have developed theories about how feminist values could reshape computing, there is a need for more research into how to practically integrate feminist values into computing practice. Additionally, given that computing education reinforces and reproduces the dominant computing culture, there is a need for further research to imagine how computing education could be transformed to teach developing technologists how to integrate feminist values into this practice. I conducted a small-sample, in-depth interview-based study to understand the experiences of people who are developing into or practicing as feminist technologists. Through my research, I identified six common characteristics of feminist technologists, including a commitment to care, awareness of power structures, practice of epistemic humility, application of systems thinking, and negotiation with the tensions in integrating feminist values. I also identified two common types of experiences that help develop people into feminist technologists: experiences that foster feminist consciousness-raising and experiences that positively model feminist values. These insights suggest alternative ways of understanding the development of feminist technologists as a continuous process, where being and becoming a feminist technologist is one and the same, that requires a foundation of emotional safety.