Search for: All records

The Plio-Pleistocene turnover event in the western Atlantic following the closure of the Central American Seaway involved high rates of extinction for both gastropod and bivalve molluscs. This extinction was associated with declining nutrient conditions and has been presumed to be associated with a decrease in molluscan body size. Previous work which has been concordant with this expectation, however, has either focused on bivalves or not considered the effects of the recovery post extinction. In three phylogenetically diverse clades, we found that body-size evolution in gastropods across the turnover event is likely tied to ecology. One clade increased in size, one decreased, and another exhibited no substantial change. Individual species lineages exhibit a mixture of microevolutionary changes from the Pliocene to today. This study indicates that gastropod body-size evolution may be more complex than in bivalves, with ecology and other functional traits playing a significant role. Macroevolutionary processes, especially whether a clade re-radiated post extinction, were found to be important. Indeed, a low portion of extant diversity consists of survivors from clades that increased in size or have similar size distributions among their species relative to the Pliocene. 

Introduction:Agriculture is the largest user of water globally (i.e., 70% of freshwater use) and within the United States (i.e., 42% of freshwater use); irrigation ensures crops receive adequate water, thereby increasing crop yields. Surfactants have been used in various agricultural spray products to increase spray stability and alter droplet sizes. Methods:The effects of the addition of surfactant (0.1 wt% Surfactin; surface tension of 29.2 mN/m) to distilled water (72.79 mN/m) on spray dynamics and droplet formation were investigated in four flat fan (206.8–413.7 kPa), one full cone (137.9–413.7 kPa), and three LEPA bubbler (41.4–103.4 kPa) nozzles via imaging. Results and discussion:The flat fan and cone nozzles experienced second wind-induced breakup (i.e., unstable wavelengths drive breakup) of the liquid sheets exiting the nozzle; the addition of surfactant resulted in an increased breakup length and a decreased droplet size. The fan nozzles volumetric median droplet diameter decreased with the addition of surfactant (e.g., decreased by 26.3–65.6 μm in one nozzle). The full cone nozzle volumetric median droplet diameter decreased initially with the addition of surfactant (27.8, 14.3, and 13.4 μm at 137.9, 206.8, and 310.3 kPa respectively), but increased at 413.7 kPa (24.3 μm). Sprays from the bubbler nozzles were measured and observed to experience Rayleigh (i.e., the droplets form via capillary pinching at the end of the jet) and first wind-induced breakup (i.e., air impacts breakup along with capillary pinching). The effect of Surfactin on droplet size was minimal for the 41.4 kPa bubbler nozzle. The addition of surfactant increased the diameter of the jet or ligament formed from the bubbler plate, thereby increasing the breakup length and the droplet size at 68.9 and 103.4 kPa (droplet size increased by 750.6 and 4,462.7 μm, respectively). 

Lean management has been widely used in manufacturing industries because it increases productivity and improves quality. However, this existing universal management framework has not been widely used in higher education. Lean Manufacturing key principles are customer value, continuous improvement and respect for individuals. The aim of the present poster is to emphasize the importance of applying lean manufacturing principles in a program for supporting the needs of underrepresented students and identifying potential beneficial outcomes. The hypothesis being tested was that providing students with the opportunity to engage in hands-on discovery-based activities, offering experience in laboratory environments, allowing them to conduct undergraduate research, and offering mentorship as part of a community would help students develop a strong self-identity in STEM and strengthening their self-efficacy, and has added value to students of different background. The results show improvements in recruitment, retention, and inclusion of students from underrepresented groups in STEM disciplines. The Kansas LSAMP alliance, led by Kansas State University, offers multiple activities aimed towards the success of underrepresented identities and first-generation students. For instance, Research Immersion: Pathways to STEM, KS-LSAMP Scholars Program, KS-LSAMP T.E.A.M Mentor Program, Transfer Visit Day, and KS-LSAMP Connect. With integrating the lean manufacturing tool of “identifying value” where value corresponds to all the characteristics or functions of something that meets a person's needs from feedback surveys, led the outcomes of activities and programs being flexible and individualized plans for each student making KS-LSAMP educational program more efficient and effective. 

Predicting the effects of anthropogenic climate change on Earth’s marine mollusk species is highly relevant, as many are critical human food resources and indispensable members of marine ecosystems. To predict which species will go extinct and which will survive, it is essential to understand the past climate species have experienced, as well as determine the relationship between functional traits, which provide a direct connection to organismal ecology, and survival. Many extant West Atlantic (WA) mollusks, especially gastropods and bivalves, survived the Mid-Pliocene Warm Period and the Last Interglacial, warm intervals compared to the present, that can serve as analogues for predicted future conditions of anthropogenic climate change. WA mollusks have an exceptional Neogene fossil record, which makes them an ideal group to study to develop a predictive extinction risk framework. The present research focuses on the correlation between functional traits and extinction in over 80 species of WA mollusks, both extant and extinct. Functional trait data such as body size, mobility, diet, bathymetric depth range, and organism-substrate relationship, which correlate with metabolic requirements, a known factor in extinction risk, and degree and type of ornamentation, shell shape in bivalves, and narrowness of the aperture in gastropods, which correlate with predation resistance, were collected across these species. These comprise both continuous and discrete character data. Various statistical tests were applied to the database to examine variable correlation/interaction, and the relative contributions of traits to extinction risk. Traits related to metabolism were strong predictors of survival; traits related to predation resistance play a less important role. While this study focuses on organismic traits, the aim of future research will be to explore how group characteristics such as geographic range are associated with functional traits and extinction risk for these species. A predictive framework is developed using patterns of extinction in the fossil record to infer survival of various species in the future, which will be relevant for evaluating the potential consequences of climate change, global change biology, and for determining which species should be targeted for conservation efforts. 

Preliminary data indicate between the latest Pliocene and recent approximately 85% of bivalves and 90% of gastropod species in Florida and the Atlantic Coastal Plain became extinct, with high levels of origination resulting in similar total species richness in the region today. We expected this event may have impacted molluscan body size as body size in mollusks is generally correlated with nutrient availability and primary productivity, which decreased following the Pliocene closure of the Central American Seaway. Previous work indicated small body size is associated with extinction survival during this event in both bivalves and gastropods. Where all extant and Pliocene members of surviving bivalve clades have been compared, these have also declined in size; comparable studies of all extant and Pliocene members of gastropod clades have not yet, however, been undertaken. We investigated 3 families of gastropods of differing ecology with both high turnover and at least one boundary-crossing lineage in order to assess the impact of the turnover event on each clade’s body size. These were the predatory Conidae, the herbivorous Tegulidae, and the suspension-feeding Turritellidae. These had approximately 65%, 75%, and 90% extinction, respectively, with modern­ diversity at 110%, 100%, and 10% of their respective Pliocene species richness in the region. Despite high levels of turnover, we found no general pattern of body-size change associated with the event either within clades or among boundary-crossing lineages. While many of the largest species of Conidae and Turritellidae did become extinct, this was balanced by the loss of smaller-bodied species, while the Tegulidae increased in size. Among ancestor-descendant pairs, 1 turritellid decreased in size while 1 remained unchanged, 4 Conidae decreased in size while 2 increased in size, and 1 tegulid increased in size. These data suggest that for gastropods there were complex interactions between ecology, extinction, origination, and body-size evolution associated with this event and that a more phylogenetically-diverse dataset is needed to determine whether generalizable patterns exist which may be used to predict responses to future environmental change. 

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. 

Atmospheric condensation is very important for multiple practical applications such as heat transfer, thermal management, aerospace, and condensate harvesting. Water droplets heterogeneously nucleate on the surfaces when the temperature is below the dew point temperature. The nucleation energy barrier for a condensed droplet varies significantly with the humidity content in the operating environment. The freezing of this condensate is also dependent on the operating conditions and surface properties. This article presents an experimental study of condensation and freezing from humid air with the objective of understanding how the surface morphology and chemistry determines the droplet shape and wetting state. Hexagonal close-packed arrays of titanium (Ti) pillars are patterned using microsphere photolithography (MPL). The Ti nanostructured surface was tested with and without a Teflon© coating to reveal the condensate harvesting, passive freezing, and dropwise condensation applications, respectively. Condensation and freezing tests were conducted in the presence of non-condensable gases (air) with different relative humidity (RH) levels to control the nucleation site density. The experiments showed that droplet growth occurs in the following stages: initial nucleation, direct growth, and coalescence events. By pinning droplets, coalescence is suppressed for the Ti nanopillared surface altering the size distribution of droplets and significantly accelerating the freezing process. 

The goal of this project is to better understand the beliefs that undergraduate students hold about their own intelligence and how these beliefs change during their undergraduate engineering education. The research team has used the theoretical framework established by Carol Dweck on Mindset and how different fixed and growth mindsets affect success. Fixed mindset individuals believe that their intelligence is an unchanging trait, while people with a growth mindset believe that through effort they can grow and develop greater intelligence. Prior researchers have shown that individuals with a growth mindset respond to challenges with higher levels of persistence, are more interested in improving upon past failures, and value criticism and effort more than those with a fixed mindset. The team developed an interview protocol from the theoretical framework. Then the team piloted the protocol and subsequently modified the protocol multiple times to ensure that the interviews provided rich qualitative data. Analytic memos were used to analyze and modify the piloted interview protocols. Once the final protocol was established, first-year and senior students were recruited to provide cross-sectional insight. The team also recruited using purposeful sampling to ensure that women and underrepresented minorities were included. To date, 19 interviews have been conducted with the final protocol. Of these interviews, four have been coded in detail using the “Attitudes, Values, and Beliefs” coding system. A codebook has also been started to categorize and interconnect the themes in the interview transcripts. This paper provides details of the protocol and coding process as well as preliminary findings on the themes extracted from the student interviews. 

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.