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Heat pipes are passive heat transfer devices crucial for systems on spacecraft; however, they can freeze when exposed to extreme cold temperatures. The research on freezing mechanisms on wicked surfaces, such as those found in heat pipes, is limited. Surface characteristics, including surface topography, have been found to impact freezing. This work investigates freezing mechanisms on wicks during condensation freezing. Experiments were conducted in an environmental chamber at 22 °C and 60% relative humidity on three types of surfaces (i.e., plain copper, sintered heat pipe wicks, and grooved heat pipe wicks). The plain copper surface tended to freeze via ice bridging—consistent with other literature—before the grooved and sintered wicks at an average freezing time of 4.6 min with an average droplet diameter of 141.9 ± 58.1  μm at freezing. The grooved surface also froze via ice bridging but required, on average, almost double the length of time the plain copper surface took to freeze, 8.3 min with an average droplet diameter of 60.5 ± 27.9  μm at freezing. Bridges could not form between grooves, so initial freezing for each groove was stochastic. The sintered wick's surface could not propagate solely by ice bridging due to its topography, but also employed stochastic freezing and cascade freezing, which prompted more varied freezing times and an average of 10.9 min with an average droplet diameter of 97.4 ± 32.9  μm at freezing. The topography of the wicked surfaces influenced the location of droplet nucleation and, therefore, the ability for the droplet-to-droplet interaction during the freezing process. 

Undergraduate research opportunities have been demonstrated to promote recruitment, retention, and inclusion of students from underrepresented groups in STEM disciplines. The opportunity to engage in hands-on, discovery-based activities as part of a community helps students develop a strong self-identity in STEM and strengthens their self-efficacy in what can otherwise be daunting fields. Kansas State University has developed an array of undergraduate research opportunities, both in the academic year and summer, and has established a management infrastructure around these programs. The Graduate School, which hosts its own Summer Undergraduate Research Opportunity Program aimed at URM and first-generation college students, coordinates the leadership of the other grant-funded programs, and conducts a series of enrichment and networking activities for students from all the programs. These include professional development as well as primarily social sessions. The Kansas LSAMP, led by Kansas State University, created a summer program aimed at under-represented minority community college students enrolled in STEM fields to recruit them into research opportunities at K-State. There has been strong interest in the program, which incorporated university experience elements in addition to an introduction to STEM research and the four-year university. In the 5 years since the program’s inception, cohorts of nine to fourteen students came to K-State each year for eight-week experiences and took part in both cohort-based sessions and individual mentored research experiences. The two-fold focus of this program, Research Immersion: Pathways to STEM, has resulted in the majority of the students presenting a poster at a national conference and transferring to a STEM major at a four-year institution. Survey results showed that the program was successful at improving STEM identity and academic self-concepts. Qualitative feedback suggested that the two parts of the program worked together to increase interest and self confidence in STEM majors but also ensured that students connect with other students and felt comfortable in the transition to a 4-year institution. 

Abstract Engineering innovations—including those in heat and mass transfer—are needed to provide food, water, and power to a growing population (i.e., projected to be 9.8 × 109 by 2050) with limited resources. The interweaving of these resources is embodied in the food, energy, and water (FEW) nexus. This review paper focuses on heat and mass transfer applications which involve at least two aspects of the FEW nexus. Energy and water topics include energy extraction of natural gas hydrates and shale gas; power production (e.g., nuclear and solar); power plant cooling (e.g., wet, dry, and hybrid cooling); water desalination and purification; and building energy/water use, including heating, ventilation, air conditioning, and refrigeration technology. Subsequently, this review considers agricultural thermal fluids applications, such as the food and water nexus (e.g., evapotranspiration and evaporation) and the FEW nexus (e.g., greenhouses and food storage, including granaries and freezing/drying). As part of this review, over 100 review papers on thermal and fluid topics relevant to the FEW nexus were tabulated and over 350 research journal articles were discussed. Each section discusses previous research and highlights future opportunities regarding heat and mass transfer research. Several cross-cutting themes emerged from the literature and represent future directions for thermal fluids research: the need for fundamental, thermal fluids knowledge; scaling up from the laboratory to large-scale, integrated systems; increasing economic viability; and increasing efficiency when utilizing resources, especially using waste products.