Engineering 498 Interdisciplinary Capstone is a required senior capstone course that creates university-industry partnerships that allow companies to tackle pressing projects through motivated engineering students and provides students with impactful real-world experience. In Engineering 498, students learn the in-depth design processes that are used in industry to provide them with the knowledge they need to succeed after graduation. The ability to put that learning into practice during the course of their senior year allows them to see how it works in real-time, before they enter the job market. Students are mentored by faculty who have retired from, or are still active, in industry so they learn from someone who actively did what they are teaching and can guide from experience. Mentors work closely with both students and sponsors to ensure the students are benefitting academically, and the sponsors are able to see progress on the projects they are sponsoring. Students also work directly with sponsors so they learn how to identify client needs, source manufacturing, and complete deliverables on a set schedule, among many other tasks. Students interested in participating in a Biosphere 2 specific project should reach out to their engineering department and John Adams at jadamsb2@arizona.edu.
Past Biosphere 2 Capstones:
Biosphere Ocean Life Support
Project number: 18116
Sponsor: UA Department of Chemical and Environmental Engineering
Academic year: 2018-2019
The 30 micron primary drum filters in the Biosphere 2 life-support system required backwash because they were failing to remove dissolved and suspended organic material from the Biosphere 2 ocean. The goal of the backwash treatment was to identify optimal conditions for reuse while simultaneously minimizing any potential waste stream. This required multiple mass balances, process train designs, and ocean chemistry knowledge. Mechanical processes such as rapid sand filtration and ultrafiltration were used to remove turbidity, and chemical processes such as ozonation and ultraviolet treatment removed harmful microbes within the backwash.
Biosphere 2 Controlled Systems Monitors
Project number: 19094
Sponsor: UA Biosphere 2
Academic year: 2019-2020
Project Goal: To design and build real-time, low-cost, high-precision, high-accuracy environmental monitoring systems for two controlled environments at Biosphere 2.This project developed two low-cost environmental monitoring systems for different controlled environments at the University of Arizona Biosphere 2. Each embedded sensor system consists of the necessary circuitry, software and mechanical housing required for their respective environments –one aquatic, and the other terrestrial. The Coral Reef Raceway Monitoring System measures water temperature, pH and salinity, housed in a compact, waterproof case with a built-in touchscreen and number pad for user input and control. It uses inexpensive components that improve upon the bulky, inconvenient and expensive commercial alternatives. The Lunar Greenhouse Monitoring System features temperature, relative humidity, and carbon dioxide air quality monitoring in a protective case that interfaces with existing equipment in use at the exhibit. Each system is equipped with an LED and email alert system to signal when values are out of desired bounds.
Biosphere Ocean Wave Generator
Project number: 19102
Sponsor: UA Biosphere 2
Academic year: 2019-2020
Project Goal: To improve the reliability of the ocean wave generator at the University of Arizona Biosphere 2so it more accurately simulates the ocean environment. The wave generator is a key piece of equipment at Biosphere 2. It ensures water is well-mixed with no stratification. This team recommended replacement parts for the wave generator. Criteria included that the replacements be readily available, low-maintenance, cost-effective, and equal to or better than the quality to existing parts. In addition, the team created a maintenance manual and troubleshooting guide for quick response to malfunctions. With the recommended upgrades, the system now has more reliable gates, automated electrical actuators, and code that controls the actuators of the system. It also monitors the water level in the troughs and activates an interlock if the water level passes a critical height.
Biosphere 2 Landscape Evolution Observatory Upgrade
Project number: 19128
Sponsor: UA Biosphere 2
Academic year: 2019-2020
Project Goal: To upgrade the existing irrigation system and design a lithium chloride tracer injection system for the Mini Landscape Evolution Observatory at Biosphere 2.The Landscape Evolution Observatory at Biosphere 2 studies how the landscape is affected by physical and biological processes, how water flow is affected by time and climate change, and how biological communities evolve in response to changes in landscape and environment. The LEO is a single, ongoing operation that cannot be paused or restarted. Therefore, Biosphere 2 researchers perform pilot-scale tests on a mini LEO before making changes to the Landscape Evolution Observatory. The team developed a comprehensive design and cost estimation for making the mini LEO's injection system compatible with existing equipment. Design constraints included the uniform distribution of rainfall, existing sensor network, and placement of irrigation heads in relation to the gas chamber and grow lights.
Pressure Regulating System for a Mars Habitat
Project number: 21066
Sponsor: UA Biosphere 2
Academic year: 2020-2021
Project Goal: Design a system that maintains a positive pressure in a closed Moon and Mars habitat to prevent the introduction of foreign contaminants. Maintaining a pressurized vessel is paramount to human survival in the hostile environment of the Moon or Mars. The Automated Pressure Regulation System will ultimately be attached to a high-fidelity Mars habitat analog at Biosphere 2 as part of research into off-world habitation. The APRS prototype is attached to a one-tenth-scale model of the analog crew quarters. An array of sensors and a Raspberry Pi computer detect the internal pressure of the living quarters. Based on these readings, the system uses a compressor and solenoid valve to either store air in tanks or release air into the system to maintain a steady pressure. A user interface enables the crew to monitor real-time internal and ambient pressures. The system can be operated in either automatic or manual mode. The scale model properly maintains the required positive pressure differential, thus validating the design. With testing concluded, the APRS is ready for full-scale implementation.
Automated system for measuring ecosystem gas fluxes in tropical forests
Project number: 22061
Sponsor: UA Biosphere 2
Academic year: 2021-2022
The chamber design is mainly to create a small air volume above (soil/water) or next to (tree stems) where gas concentrations change much faster than in ambient air, which then can be used to calculate surface fluxes. To measure the gas concentrations the air is circulated between the instrument and the chamber. The control interface would capture the change in gas concentrations, switch between different chambers (we plan to measure 10 tree stems and 5 soil/water surfaces), but also control the pistons that push the chamber against a tree stem surface or a base on the soil or water surface to seal the chamber against the surface.
Sub-scale Adsorption and Compression CO2 Removal System Re-design
Project number: 22014
Sponsor: NASA
Academic year: 2021-2022
The student team effort will include design, thermal-flow modeling, build, and test of a sub-scale TC-TSAC to determine its capability to integrate CO2 removal and compression into a single system. SAM team members and individuals at NASA will oversee requirements definition and provide system design assistance and data- sharing. The projects and products of the challenge will be evaluated by NASA subject matter experts currently working in the topic area and may be integrated into prototypes for the purpose of operational and functional evaluation opportunities.
Ocean Light Control
Project number 25007
Organization UA Biosphere 2
Offering ENGR498-F2024-S2025
Coral conservation research depends on the ability to reliably and accurately control lighting. This project aimed to develop a personalized website that gives users the ability to send color and intensity commands to a series of Maxspect 500W LED commercial floodlights at Biosphere 2’s coral research space.
The team’s design works by sending light settings from the main system to individual controllers on the lights via controller area network bus communication protocol. The design includes one Raspberry Pi 5 and three Raspberry Pi Picos that serve as the main and individual controllers, respectively. Each light is equipped with a Raspberry Pi Pico integrated with two digital potentiometers that allow operators to precisely adjust lighting parameters based on given commands.
Users can also apply 24-hour lighting schedules and receive real-time feedback from a photosynthetic active radiation sensor. This allows them to monitor and detect out-of-range intensity values. Additionally, the team gave each microcontroller a housing unit to protect it from the environment and the capability to dissipate heat produced from the electronics. This system enables enhanced lighting control and data collection to support coral conservation research at the U of A Biosphere 2 facility.
Coral Reef Arks Hydrodynamics
Project number 26022
Organization UA Biosphere 2
Offering ENGR498-F2025-S2026
Students shall propose three additional Ark design concepts for comparative evaluation. Each proposed design shall be analyzed using both 1V and 2V geodesic sphere configurations to explore structural feasibility and performance. Students shall also develop a model that demonstrates the hydrodynamic stability of each design under expected environmental conditions.
To validate their analyses, students shall construct smaller-scale physical models of each design for wind-tunnel and/or in-water testing. Following these tests, students shall clearly articulate the benefits, drawbacks, and trade-offs of each concept. Based on the combined results of modeling and physical testing, students shall identify one standout design and provide a well-supported justification for its selection.
Autonomous 3D-Printed Leaf Chamber - Developing a Portable Device for Gas Exchange Measurements on Large Tropical Rainforest Leaves
Project number 26040
Organization UA Biosphere 2
Offering ENGR498-F2025-S2026
Trees, in particular topical trees, have a large impact on the global carbon cycling and with increasing climate change we need to understand the feedbacks of natural ecosystems on the global atmosphere. Trees interact with the surrounding air mainly through their leaves, so it is of particular interest for ecosystem ecologists to understand how individual leaves interact with the air in real-time and under conditions we humans do not thrive in.
Researchers have measured leaf gas exchange for many years, either with handheld instruments (slow and not easily repeatable) or with leaf/branch bags or leaf cuvettes. Most of these have a strong impact on the leaf environmental conditions by modifying the light, temperature or humidity. These modifications also impact the leaf functioning and these methods thus do not yield reliable results. Recent development of autonomous small leaf cuvettes that can be 3D printed (https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10516825) appears to be a new method that might help ecologists to measure leaf gas exchange with minimal impact on leaves.
Scope: 1) with the sponsors research the current design (connect with the researchers who have developed it) and see how it can be improved upon, 2) evaluate the control requirements for reliable and controllable closure of the cuvette design, 3) design the small autonomous leaf cuvette, the electronic control system, and computer code to control the system 4) build (3D print the cuvette and control electronics box) a proto-type complete with mechanical and electronic diagrams and computer code, 5) test the proto-type in the Biosphere 2 rainforest ecosystem to test the system under realistic environmental conditions; 6) develop the plans to transform the prototype into a system that can be deployed on leaves of multiple species in the Biosphere 2 rainforest, and 7) present the results at design day and potentially at a conference.
The sponsor will supply the instrumentation needed to make gas exchange measurements.