Smart Platform for Low-Cost MEMS Sensors – Pressure, Flow and Thermal Conductivity

In a technological world that is trending towards smart and autonomous engineering, the collection of quality data is of unrivalled importance. This has led to a huge market demand for the development of low-cost, small and accurate sensors and thus has resulted in significant research into sensors, with the aim of advancing the price/performance ratio in commercial solutions. Micro Electro Mechanical Systems (MEMS) have recently offered an attractive solution to miniaturise and drastically improve the performance of sensors. In this thesis, MEMS technology is exploited to create a multi-sensor technology platform that is used to fabricate several sensing technologies. Piezo-resistive and piezo-electronic pressure sensors are designed, fabricated and tested. Different doping profiles, stress-engineered structures and electronic devices for pressure transduction are investigated, with focus on their sensitivity and non-linearity. A ring is fabricated in the metal layer around the circumference of the membrane that alleviates the effects of over/under etching. This is achieved by creating a new rigid edge of the membrane in the metal layer, which has tighter fabrication tolerances. A piezo-MOSFET is developed and shown to have greater sensitivity than similar state-of-the-art devices. Flow sensors based on a heated tungsten wire are designed, fabricated, tested and substantiated with numerical modelling. Calorimetric and anemometric driving modes are optimised with regards to device structure. Thermodiodes are also used as the temperature transduction devices and are compared to the traditional resistor method and showed to be preferable when further miniaturising the sensor. Thermal conductivity gas sensors based on a heated tungsten resistor are designed, tested and substantiated with numerical modelling. Holes through the membrane are used to improve the sensitivity to measuring carbon dioxide by 270%. Asymmetric holes are utilised to prove a novel method of measuring thermal conductivity in a calorimetric method. Designs improving this new concept are outlined and substantiated with analytical and numerical models. Linear statistical methods and artificial neural networks are used to differentiate flow rate and gas concentration using three on-membrane resistors. With membrane holes, the discrimination between gases in the presence of flow is improved. Neural networks provide a viable solution and show an increase in the accuracy of both flow rate and gas concentration. The main objective of the work in this thesis was to develop low-cost, low-power, small devices capable of high-volume production and monolithic integration using a single smart technology platform for fabrication. The smart technology platform was used to create pressure sensors, flow sensors and thermal conductivity gas sensors. Within each sensing technology, proof-of-concepts and optimisations have been carried out in order to maximise performance whilst using the low-cost, high-volume fabrication process, ultimately helping towards smart and autonomous engineering solutions driven by data

The Role of the Expansion Segment 7 of 25S rRNA During Oxidative Stress in Saccharomyces cerevisiae

Translation is an essential process for protein expression in both eukaryotes and prokaryotes. Like any cellular process, translational factors are prone to damage when the cell is under stress. One common stressor that nearly all cells may experience is abnormal levels of reactive oxygen species (ROS). Damage caused by ROS has been associated with disease ranging from neurodegenerative impairments, to the aging process of cells. These oxygen radicals are capable of damaging a litany of molecules including nucleic acids, and molecular factors involved in translation. It has been shown that tRNA can be cleaved upon ROS-induced stress and these fragments come to serve as signaling molecules. However, to date there is very little research that has been done to investigate whether or not rRNAs are capable of similar signaling. Presented in this dissertation is an observed endonucleolytic cleavage in the ES7c region of eukaryotic 25S rRNA, which results in rRNA fragments formation. Herein, experimentation is presented that shows a relationship between elevated levels of ROS, in particular H2O2, and ES7c-cleavage. The results presented in this dissertation aim to provide further understanding of this observed rRNA cleavage. The groundwork established during this project serves as a foundation for further research into the nature of this phenomenon. The protocols and procedures that were developed during this project will provide our laboratory with necessary tools for future projects regarding ROS, apoptosis, and rRNA fragmentation

Heavy Lift Mobility Platform (AIAA 2024)

We present a design for a new heavy lift aircraft to replace the existing C-5M and C-17 fleet for USAF Air Mobility Command. Design requirements and specifications are taken from an RFP from the American Institute of Aeronautics and Astronautics (AIAA). A video presentation of the design can be found here: https://www.youtube.com/watch?v=wdmCVdGXyL

Modification of the Ribosome as Part of the Adaptive Response to Oxidative Stress in Yeast

Living organisms are constantly exposed to a variety of environmental and internal stressors tha tare detrimental to their cellular physiology and viability. One such condition, oxidativestress, is caused by abnormal amounts of Reactive Oxygen Species (ROS) that can lead to damage to proteins, nucleic acids, and lipids. Although the mechanisms to neutralize ROS have been widely studied, the understanding of ROS‐mediated signaling for these mechanisms is rather incomplete and sparse. We have uncovered a previously undescribed phenomenon of yeast ribosomes to respond to elevated levels of ROS through a specific endonucleolytic cleavage of the 25S rRNA in the c‐loop of the expansion segment 7 (ES7c) regions

Endonucleolytic Cleavage in the Expansion Segment 7 of 25S rRNA Is an Early Marker of Low-Level Oxidative Stress in Yeast

The ability to detect and respond to oxidative stress is crucial to the survival of living organisms. In cells, sensing of increased levels of reactive oxygen species (ROS) activates many defensive mechanisms that limit or repair damage to cell components. The ROS-signaling responses necessary for cell survival under oxidative stress conditions remain incompletely understood, especially for the translational machinery. Here, we found that drug treatments or a genetic deficiency in the thioredoxin system that increase levels of endogenous hydrogen peroxide in the yeast Saccharomyces cerevisiae promote site-specific endonucleolytic cleavage in 25S ribosomal RNA (rRNA) adjacent to the c loop of the expansion segment 7 (ES7), a putative regulatory region located on the surface of the 60S ribosomal subunit. Our data also show that ES7c is cleaved at early stages of the gene expression program that enables cells to successfully counteract oxidative stress and is not a prerequisite or consequence of apoptosis. Moreover, the 60S subunits containing ES7c-cleaved rRNA cofractionate with intact subunits in sucrose gradients and repopulate polysomes after a short starvation-induced translational block, indicating their active role in translation. These results demonstrate that ES7c cleavage in rRNA is an early and sensitive marker of increased ROS levels in yeast cells and suggest that changes in ribosomes may be involved in the adaptive response to oxidative stress

The role of cell-envelope synthesis for envelope growth and cytoplasmic density in Bacillus subtilis

All cells must increase their volumes in response to biomass growth to maintain intracellular mass density within physiologically permissive bounds. Here, we investigate the regulation of volume growth in the Gram-positive bacterium Bacillus subtilis. To increase volume, bacteria enzymatically expand their cell envelopes and insert new envelope material. First, we demonstrate that cell-volume growth is determined indirectly, by expanding their envelopes in proportion to mass growth, similarly to the Gram-negative Escherichia coli, despite their fundamentally different envelope structures. Next, we studied, which pathways might be responsible for robust surface-to-mass coupling: We found that both peptidoglycan synthesis and membrane synthesis are required for proper surface-to-mass coupling. However, surprisingly, neither pathway is solely rate-limiting, contrary to wide-spread belief, since envelope growth continues at a reduced rate upon complete inhibition of either process. To arrest cell-envelope growth completely, the simultaneous inhibition of both envelope-synthesis processes is required. Thus, we suggest that multiple envelope-synthesis pathways collectively confer an important aspect of volume regulation, the coordination between surface growth, and biomass growth.Fil: Kitahara, Yuki. University of Montreal; Canadá. Universite de Paris; Francia. Instituto Pasteur; FranciaFil: Ordewurtel, Enno. Instituto Pasteur; FranciaFil: Sean, Wilson. Harvard University; Estados UnidosFil: Yingje, Sun. Harvard University; Estados UnidosFil: Altabe, Silvia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: de Mendoza, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Gardner, Ethan. Harvard University; Estados UnidosFil: Van Teefelen, Sven. University of Montreal; Canadá. Institut Pasteur de Paris.; Franci

CAPSTONE: A CubeSat Pathfinder for the Lunar Gateway Ecosystem

The cislunar environment is about to get much busier and with this increase in traffic comes an increase in the demand for limited resources such as Earth based tracking of and communications with assets operating in and around the Moon. With the number of NASA, commercial, and international missions to the Moon growing rapidly in the next few years, the need to make these future endeavors as efficient as possible is a challenge that is being solved now. Advanced Space is aiming to mitigate these resource limitations by enabling the numerous spacecraft in the cislunar environment to navigate autonomously and reduce the need for oversubscribed ground assets for navigation and maneuver planning. Scheduled to launch on a Rocket Lab Electron in October 2021, the Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) mission will leverage a 12U CubeSat to demonstrate both the core software for the Cislunar Autonomous Positioning System (CAPS) as well as a validation of the mission design and operations of the Near Rectilinear Halo Orbit (NRHO) that NASA has baselined for the Artemis Lunar Gateway architecture. Currently being developed in a Phase III of NASA’s SBIR program, our CAPS software will allow missions to manage themselves and enable more critical communications to be prioritized between Earth and future cislunar missions without putting these missions at increased risk. CAPSTONE is the pathfinder mission for NASA’s Artemis program. The overall mission will include collaboration with the Lunar Reconnaissance Orbiter (LRO) operations team at NASA Goddard Space Flight Center to demonstrate inter-spacecraft ranging between the CAPSTONE spacecraft and LRO and with the NASA Gateway Operations team at NASA Johnson Space Center to inform the requirements and autonomous mission operations approach for the eventual Gateway systems. Critical success criteria for CAPSTONE in this demonstration are a transfer to and arrival into an NRHO, semi-autonomous operations and orbital maintenance of a spacecraft in an NRHO, collection of inter-spacecraft ranging data, and execution of the CAPS navigation software system on-board the CAPSTONE spacecraft. Advanced Space along with our partners at NASA’s Space Technology Mission Directorate, Advanced Exploration Systems, Launch Services Program, NASA Ames Small Spacecraft Office, Tyvak Nano-Satellite Systems and Rocket Lab, envision the CAPSTONE mission as a key enabler of both NASA’s Gateway operations involving multiple spacecraft and eventually the ever-expanding commercial cislunar economy. This low cost, high value mission will demonstrate an efficient low energy orbital transfer to the lunar vicinity and an insertion and operations approach to the NRHO that ultimately will demonstrate a risk reducing validation of key exploration operations and technologies required for the ultimate success of NASA’s lunar exploration plans, including the planned human return to the lunar surface. This presentation will include the current mission status (which would include the launch and early mission operations), the operations plan for the NRHO, and lessons learned to date in order to inform future CubeSat pathfinders in support of national exploration and scientific objectives

LoRaWAN Battery-Free Wireless Sensors Network Designed for Structural Health Monitoring in the Construction Domain.

This paper addresses the practical implementation of a wireless sensors network designed to actualize cyber-physical systems that are dedicated to structural health monitoring applications in the construction domain. This network consists of a mesh grid composed of LoRaWAN battery-free wireless sensing nodes that collect physical data and communicating nodes that interface the sensing nodes with the digital world through the Internet. Two prototypes of sensing nodes were manufactured and are powered wirelessly by using a far-field wireless power transmission technique and only one dedicated RF energy source operating in the ISM 868 MHz frequency band. These sensing nodes can simultaneously perform temperature and relative humidity measurements and can transmit the measured data wirelessly over long-range distances by using the LoRa technology and the LoRaWAN protocol. Experimental results for a simplified network confirm that the periodicity of the measurements and data transmission of the sensing nodes can be controlled by the dedicated RF source (embedded in or just controlled by the associated communicating node), by tuning the radiated power density of the RF waves, and without any modification of the software or the hardware implemented in the sensing nodes

CAPSTONE: A Summary of Flight Operations to Date in the Cislunar Environment

The cislunar environment is about to get much busier and with this increase in traffic comes an increase in the demand for limited resources such as Earth based tracking of and communications with assets operating in and around the Moon. With the number of NASA, commercial, and international missions to the Moon growing rapidly, the need to make these future endeavors as efficient as possible is a challenge that is being solved now. Advanced Space is aiming to mitigate these resource limitations by enabling spacecraft in the cislunar environment to navigate autonomously and reduce the need for oversubscribed ground assets for navigation and maneuver planning. Launched in June 2022, the Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) mission utilizes a 12U CubeSat to demonstrate both the core software for the Cislunar Autonomous Positioning System (CAPS) as well as a validation of the mission design and operations of the Near Rectilinear Halo Orbit (NRHO) that NASA has baselined for the Artemis Lunar Gateway architecture. The CAPS software enables cislunar missions to manage their navigation functions themselves and reduces the reliance on Earth based tracking requirements without putting these missions at increased risk. Upon arrival in the NRHO, the CAPSTONE spacecraft will soon initiate its navigation demonstration mission in collaboration with the Lunar Reconnaissance Orbiter (LRO) operations team at NASA’s Goddard Space Flight Center to demonstrate autonomous inter-spacecraft ranging and autonomous navigation between the CAPSTONE spacecraft and LRO. Critical success criteria for CAPSTONE in this demonstration are 1) semi-autonomous operations and orbital maintenance of a spacecraft in an NRHO, 2) collection of inter-spacecraft ranging data, and 3) execution of the CAPS navigation software system in autonomous mode on-board the CAPSTONE spacecraft. Additionally, CAPSTONE continues to demonstrate an innovative one-way ranging navigation approach utilizing a Chip Scale Atomic Clock (CSAC), unique firmware installed on the Iris radio, and onboard autonomous navigation algorithms developed JPL an implemented by Advanced Space. Advanced Space, along with our partners at NASA’s Space Technology Mission Directorate, (STMD), Advanced Exploration Systems (AES), Launch Services Program (LSP), NASA Ames’ Small Spacecraft Office, the Jet Propulsion Lab (JPL), Terran Orbital and Rocket Lab, envision the CAPSTONE mission as a key enabler of both NASA’s upcoming Gateway operations involving multiple spacecraft and eventually the ever-expanding commercial cislunar economy. Over the next 21 months, CAPSTONE will demonstrate an efficient low energy orbital transfer to the lunar vicinity, an insertion into the NRHO, and a risk reducing validation of key exploration operations and technologies required for the ultimate success of NASA’s lunar exploration plans. This paper includes an overview of the mission, the current mission operational status, lessons learned from the launch, lunar transfer, and insertion into the NRHO, an overview of operations plan for the NRHO, and other lessons learned to date in order to inform future missions in support of national exploration and scientific objectives

CAPSTONE: A Summary of a Highly Successful Mission in the Cislunar Environment

NASA, Advanced Space, Terran Orbital, Rocket Lab, Stellar Exploration, JPL, the Space Dynamics Lab, and Tethers Unlimited have partnered to successfully develop, launch, and operate the Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) mission, which is serving as a pathfinder for Near Rectilinear Halo Orbit (NHRO) operations around the Moon. This low-cost, high-value mission has demonstrated an efficient, low-energy orbital transfer to the Moon and a successful insertion into the Near Rectilinear Halo Orbit (NRHO), the intended orbit for NASA\u27s Gateway lunar orbital platform. The mission is now demonstrating operations within the NRHO that ultimately will serve to reduce risk and validate key exploration operations and technologies required for the future success of NASA\u27s lunar exploration plans, including the planned human return to the lunar surface. Over the next 9+ months, CAPSTONE will continue to validate these key operations and navigation technologies required for the success of NASA\u27s lunar exploration plans. This paper will include an overview of the current mission status, lessons learned from the launch, transfer, and insertion into the NRHO, a summary of the challenges encountered thus far, and an overview of the successful mission operations technology demonstrations thus far