Thermal Modeling of FEMTA Micropropulsion System for CubeSat Attitude Control

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 seconds specific impulse. Liquid ultra-pure deionized water is used as a dense, safe, and abundantly available propellant source. A complete FEMTA six degree-of-freedom propulsion system including zero-gravity propellant management is being developed at Purdue University in preparation for a future orbital flight demonstration. It is suspected that the performance and long-term reliability of FEMTA will be sensitive to temperature fluctuations within this propulsion system while in orbit. Specifically, a reduction in propellant temperature may result in ice generation within the FEMTA chips and an increase in propellant temperature will reduce total DeltaV through higher quiescent propellant loss. We present an investigation of FEMTA propulsion system thermal response in Low Earth Orbit (LEO). A generalizable analysis process was developed for LEO CubeSat missions using finite element models in ANSYS. This analysis process was applied to a preliminary CubeSat mission design to investigate FEMTA propulsion system transient-thermal behavior. Model accuracy and recommendations for future improvements to the process are discussed

The Relationship Between the Supervisory Alliance and Novice Supervisees’ Risk-Taking Behavior

Supervisee risk-taking is the process by which supervisees take the new skills and interventions they learn in supervision and implement them in therapy with clients. Risk-taking overlaps with many of the skills supervision is intended to develop: clinical decision-making, supervisee self-efficacy, supervisee skill development, and clinical reflection (Bambling & King, 2014; Ellis et al., 2014; Rousmaniere et al., 2016; Wilson et al., 2016). Risk-taking has not been examined before the in the supervision literature, however, it is an important process to understand as it represents a process bridging supervision and clinical practice. The current study was an exploratory study intended to examine whether the strength of the supervisory relationship facilitates novice supervisee risk-taking in therapy. Results of the study did not find a significant relationship between the supervisory alliance and supervisee risk-taking. However, survey responses and interviews with participants illuminated the types of behaviors novice supervisees consider risky and how they make decisions around taking risks with clients. Their responses suggest that novice supervisees take risks with their clients as they try to meet their clients’ needs in the moment. Analysis found that 77.8% (n=7) of supervisees interviewed decided to take a risk to benefit either the client, therapeutic relationship, or treatment goals. Furthermore, results from the interviews revealed that for 88.9% (n=8) of supervisees, the risk was worth taking and increased their desire to take more risks in the future. Future research is recommended to understand how supervision can help supervisees make meaning of these risks

Propellant Management of Water-Based Microthruster for Suborbital 0G Testing

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 \u3c 1 W of power in \u3c 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

Multiple Reaction Monitoring Profiling (MRM-Profiling) of Lipids To Distinguish Strain-Level Differences in Microbial Resistance in Escherichia coli

The worldwide increase in antimicrobial resistance is due to antibiotic overuse in agriculture and overprescription in medicine. For appropriate and timely patient support, faster diagnosis of antimicrobial resistance is required. Current methods for bacterial identification rely on genomics and proteomics and use comparisons with databases of known strains, but the diagnostic value of metabolites and lipids has not been explored significantly. Standard mass spectrometry/chromatography methods involve multiple dilutions during sample preparation and separation. To increase the amount of chemical information acquired and the speed of analysis of lipids, multiple reaction monitoring profiling (MRM-Profiling) has been applied. The MRM-Profiling workflow includes a discovery stage and a screening stage. The discovery stage employs precursor (PREC) ion and neutral loss (NL) scans to screen representative pooled samples for functional groups associated with particular lipid classes. The information from the first stage is organized in precursor/product ion pairs, or MRMs, and the screening stage rapidly interrogates individual samples for these MRMs. In this study, we performed MRM-Profiling of lipid extracts from four different strains of Escherichia coli cultured with amoxicillin or amoxicillin/clavulanate, a β-lactam and β-lactamase inhibitor, respectively. t tests, analysis of variance and receiver operating characteristic (ROC) curves were used to determine the significance of each MRM. Principal component analysis was applied to distinguish different strains cultured under conditions that allowed or disallowed development of bacterial resistance. The results demonstrate that MRM-Profiling distinguishes the lipid profiles of resistant and nonresistant E. coli strains

The Anti-Inflammatory Effects of Ulinastatin in Trauma Patients with Hemorrhagic Shock

We investigated the use of ulinastatin in association with the suppression of polymorphonuclear leukocyte elastase (PMNE), tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6), and its effects on the prognosis of patients with traumatic hemorrhagic shock. Nineteen patients who visited the emergency department for traumatic hemorrhagic shock were enrolled. Eleven patients were randomly selected to receive a total of 300,000 IU of ulinastatin. Measurements of serum PMNE, TNF-α and IL-6 were taken before ulinastatin treatment at 24 hr, two days, three days, and seven days after admission. We compared the Systemic Inflammatory Response Syndrome scores, Multiple Organ Dysfunction Syndrome scores and Acute Physiology, age, Chronic Health Evaluation III scores of the control and ulinastatin groups. There were no significant differences in baseline values, laboratory data, treatment or mortality between the two groups. The serum PMNE levels in the ulinastatin group were lower than in the control group on the second hospitalized day. Serum TNF-α and IL-6 levels in the ulinastatin group decreased 24 hr after admission but had no significance. It is suggested that ulinastatin treatment could decrease the serum PMNE levels in trauma patients with hemorrhagic shock at 48 hr after treatment