Model Block Press

The Center for Vocational Building Technology came to the Mechanical Engineering department at Cal Poly, San Luis Obispo with a project to create a new, less expensive model block press than their current BP9 design. This press would produce ¼ scale model compressed earth blocks to be sold as souvenirs and used in demonstrations for constructing buildings. After analyzing the design of the current block presses, JCM came up with the BP10 design. The BP10 operates similarly to the larger block presses, but will cost significantly less to produce and will have some of the design features enhanced to make it easier to use

Comparison of mini-channel condensation heat transfer for R513A and R134a

There is increased interest in emerging, low global warming potential (GWP) refrigerants due to With tthe phase out of hydrofluorocarbon (HFC) refrigerants (e.g., R134a); and the need for lower global warming potential (GWP) replacements, there are many questions that still need to be answered about replacement refrigerants, including heat transfer performance. One promising alternative to R134a (GWP = 1300) is R513A (GWP = 573), which is a non-flammable mixture comprised of 44% R134a and 56% R1234yf by weight. While this low GWPR513A refrigerant is attractive due to its lower GWP and A1 flammability rating, heat transfer data are limited. Condensation experiments were conducted for R134a and R513A in a vapor compression loop using multiport (i.e., 9 parallel channels) extruded aluminum tubes; each channel’s hydraulic diameter was 0.72 mm. Experiments covered a range of average qualities (e.g., 0.2 \u3c x \u3c 0.8) and mass fluxes (e.g., 300 \u3c G \u3c 500 kg/m2s). Heat transfer coefficients and pressure drops are reported. The heat transfer coefficients of R513A were found to be very similar to R134a. Condensation data weare compared to the condensation heat transfer coefficient correlations developed by Shah (2009) and Kim and Mudawar (2013). The MAE of the Shah correlation for R513A was 22% and 6.5% for the Kim and Mudawar (2013) correlation for R513A

Impact of AI on the HRI Dynamic in Search and Rescue Operations using Uav Swarms

Artificial intelligence (AI) offers significant benefits in search and rescue applications by enhancing the efficiency and effectiveness of the search. However, an over-reliance on AI can hinder the operation due to biases embedded in the underlying algorithms. This partiality, if left un-monitored, can pose a risk to the safety of those in need of disaster relief. Typically manifests into inaccuracies in the decision-making processes and if not carefully monitored can cause larger issues. This paper extends the knowledge presented in a previous work, which presents the design and modeling of search and rescue operations using unmanned aerial vehicle (UAV) swarms. The search and rescue operations using UAV swarms (SAROUS) model is modernized by introducing artificial intelligence to the operation framework that ideally will reduce the operator workload. The results suggest that a trade-off exists between operator fatigue, task correctness, and operation timeliness. This is due to the amount of work generated and needing to be processed manually by the operator rather than automatically by an AI algorithm. Both the operator and AI contribute to some level of error when processing tasks, which influence the overall effectiveness of the operation. The performance of the operator and swarm is estimated under this new operation design and the dynamic of the human-robot interaction is analyzed. 11Research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-22-2-0199. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein

Permeability Analysis of Additively-Manufactured Wick Structures with Heat Exchanger Applications

Heat pipes and other heat transfer applications use capillary-driven liquid motion to enhance performance. This research uses water and a low surface tension fluid FC-40 to test additive-manufactured polymer wicks using a rateof-rise test. The rate-of-rise tests give a measure of the wicks’ performance capabilities as well as being able to calculate the wicks’ permeability and effective pore radius. Four wicks were measured having two different internal structures (i.e., 1.0 mm triangle and 1.75 mm square) and two external structures (i.e., layered and column). The 1.0 mm Triangle wicks performed better than their 1.0 mm Square counterparts for both water and FC-40. Both 1.0 mm Triangle wicks performed similarly for both water and FC-40, with the column wick (11.0 mm) performing better than the layered wick (8.98 mm). Using a least squares method from the rate-of-rise results, the permeability and effective pore radius of each wick were calculated for the 1.0 mm triangle layered wick, the 1.75 mm square layered wick, and the 1.0 mm triangle column wick. The 1.75 mm square column wick was unable to wick either liquid, so the permeability and effective pore radius were not able to be calculated. The permeability and effective pore radius for each wick were 3.00 um2 and 130.1 um, 0.95 um2 and 221.1 um, and 77.8 um2 and 1099 um, respectively. Some challenges involved with polymer additive manufacturing design and creation were also discussed

Layered wicks enable passive transport of condensation out of cooling systems

Layered wicks enable passive transport of condensation out of cooling systems Nhicolas Aponte, Jordan Morrow, Gennifer Riley, Partha Chakraborty, Melanie M. Derby Department of Mechanical and Nuclear Engineering, Kansas State University Cooling systems, like condensers or cooling towers of a power plant, transfer heat out of a system. The cooling process often occurs through the condensation of water, which forms a liquid film that reduces heat transfer. This problem makes cooling systems larger and more costly. One approach to this problem is drop-wise condensation in which condensed water gathers in the form of droplets which can then run off, preventing the reduction of heat transfer caused by the liquid film. For this solution to be effective in industry, a hydrophobic coating would need to last over 10 years, which is difficult to achieve. The approach studied in this work uses the capillary/surface tension forces to passively transport water, which is applicable to removing liquid films from condensers. This is investigated by using a wick, which is a structure that enables the passive transport of water. In this project, we compare wicking structures with different porosity in order to design an effective wick for industrial use. The wicks used are an array of layered spheres bridged by cylindrical columns with calculated porosity of 0.35(Wick C), 0.42(Wick B), and 0.66(Wick A). The wicks are 3-D printed onto a test plate, which allows the fabrication of complex geometries. The effectiveness of the wicks is compared using the rate-of-rise method. For this method, the wicks are lowered into a water reservoir. The interactions between the wick and the water are observed and recorded under a high speed camera. Then, the height the water rises to within the wick is compared. The wicks printed for this project outline problems we did not account for. The small pore volume of the wicks made it difficult to clean out support material after being printed. Future wicks will be designed with a greater pore volume than that of Wick C. The success of this project could improve the heat transfer in space cooling systems and power plant condensers

Effects of estrogen and progesterone on neuroactive steroids and cytokines in patients with suicidality

BACKGROUND: In ovulating psychiatric patients experiencing suicidality, suicidal ideation (SI) often peaks perimenstrually. Our recent double-blind, placebo-controlled, crossover randomized clinical trial (RCT; NCT03720847) showed that perimenstrual administration of estradiol and progesterone (EP) can prevent this peak in SI and depressed mood. In this pre-registered follow-up analysis, we studied how the menstrual cycle and experimental manipulation affected two neurobiological systems associated with the menstrual cycle and suicide risk: GABAergic neuroactive steroids (NAS) and peripheral cytokines. METHODS: In 26 psychiatric outpatients with natural menstrual cycles and past-month SI, we analyzed serum samples from three blood draws (midluteal, perimenstrual, midfollicular) per experimental condition (EP vs placebo) timed to a luteinizing hormone-surge ovulation test. Using gas chromatography/mass spectrometry (GC/MS), we measured the progesterone (P4)-derived pregnane NAS (3α,5α)- 3-hydroxypregnan20-one (3α,5α-THP), (3α,5β)- 3-hydroxypregnan-20-one (3α,5β-THP), (3α,5α)- 3,21-dihydroxypregnan-20-one (3α,5α-THDOC), (3α,5α)- 3-hydroxyandrostan-17-one (3α,5α-A), the androstane NAS (3α,5β)- 3-hydroxyandrostan-17-one (3α,5β-A), (3α,5α,17β)-androstane-3,17-diol (3α,5α-A-diol), (3α,5β,17β)-androstane-3,17-diol (3α,5β-A-diol), and their precursor pregnenolone. High sensitivity multiplex assay kits quantified peripheral cytokines IL-1β, IL-6, and TNF-α. RESULTS: P4-derived NAS fluctuated in parallel with P4 and increased with exogenous perimenstrual administration of EP. Conversely, androstane NAS either did not fluctuate or fluctuated inversely from P4, and these NAS decreased with exogenous EP. Peripheral cytokines did not show cyclical patterns, but each significantly predicted SI, depressed mood, or anxiousness. Concomitant SSRI medication use predicted lower androstane NAS. CONCLUSIONS: While preliminary and exploratory, our findings provide critical descriptive context for future studies. Further, our work presents menstrual cycle-related patterns for ten frequently-studied biomarkers, allowing for improved quality of comparisons involving naturally-cycling populations in research

The Airway Microbiome at Birth.

Alterations of pulmonary microbiome have been recognized in multiple respiratory disorders. It is critically important to ascertain if an airway microbiome exists at birth and if so, whether it is associated with subsequent lung disease. We found an established diverse and similar airway microbiome at birth in both preterm and term infants, which was more diverse and different from that of older preterm infants with established chronic lung disease (bronchopulmonary dysplasia). Consistent temporal dysbiotic changes in the airway microbiome were seen from birth to the development of bronchopulmonary dysplasia in extremely preterm infants. Genus Lactobacillus was decreased at birth in infants with chorioamnionitis and in preterm infants who subsequently went on to develop lung disease. Our results, taken together with previous literature indicating a placental and amniotic fluid microbiome, suggest fetal acquisition of an airway microbiome. We speculate that the early airway microbiome may prime the developing pulmonary immune system, and dysbiosis in its development may set the stage for subsequent lung disease

Effects of adult aging on reading filtered text: evidence from eye movements

Objectives. Sensitivity to spatial frequencies changes with age and this may have profound effects on reading. But how the actual contributions to reading performance made by the spatial frequency content of text differs between young (18–30 years) and older (65+ years) adults remains to be fully determined. Accordingly, we manipulated the spatial frequency content of text and used eye movement measures to assess the effects on reading performance in both age groups. Method. Sentences were displayed as normal or filtered to contain only very low, low, medium, high, or very high spatial frequencies. Reading time and eye movements were recorded as participants read each sentence. Results. Both age groups showed good overall reading ability and high levels of comprehension. However, for young adults, normal performance was impaired only by low and very low spatial frequencies, whereas normal performance for older adults was impaired by all spatial frequencies but least of all by medium. Conclusion. While both young and older adults read and comprehended well, reading ability was supported by different spatial frequencies in each age group. Thus, although spatial frequency sensitivity can change with age, adaptive responses to this change can help maintain reading performance in later life

Analyzing the carbon dioxide emissions of R134a alternatives in water-cooled centrifugal chillers using the life cycle climate performance framework

Introduction: To reduce greenhouse gases, the Kigali Amendment to the Montreal Protocol seeks a phasedown of hydrofluorocarbons. R134a alternatives were analyzed for use in a water-cooled chiller: R450A, R513A, R516A, R1234ze (E), R515A, and R515B.Methods: A thermodynamic model of the chiller was employed to calculate compressor power, an input to the life cycle climate performance (LCCP) framework to estimate total equivalent carbon dioxide emissions, CO2eq. Emissions were calculated for an 809 kW [230 Tons of refrigeration (RT) nameplate] water-cooled centrifugal chiller at constant cooling capacity using five power sources (i.e., coal, distillate fuel oil, natural gas, nuclear, and wind) for a median chiller lifetime of 27 years. Two chiller operating profiles were considered: one using operational data from a university campus and a second from literature based on the Atlantic Fleet operation.Results and discussion: When powered via fossil fuels, over 90% of emissions were due to the indirect emissions from energy; therefore, the global warming potential (GWP) of the refrigerant was not the primary contributor to the total CO2eq emissions. With natural gas, total LCCP emissions were reduced for R450A (7.8%), R513A (4.7%), R516A (9.4%), R1234ze (E) (10%), R515A (8.4%), and R515B (6.4%) compared to R134a for the university campus load profile. For the round-the-clock Atlantic Fleet profile, there were emission reductions for R450A (3.6%), R513A (0.25%), R516A (2.3%), R1234ze (E) (2.4%), R515A (1.5%) and R515B (2.4%) compared to R134a. When coupled with renewable energy, the indirect emissions from the chillers substantially decreased, and GWP-dependent leakage emissions accounted for up to 74% or 40% of emissions from R134a alternatives powered by wind and nuclear, respectively. For operation using the load profile from the university campus chillers, R450A had the highest coefficient of performance (COP) of 5.802, while R513A had the lowest COP (5.606). Tradeoffs between alternative refrigerants exist in terms of operation, temperature glide, size of heat exchangers, system design, flammability, cost, availability, and material compatibility. In terms of flammability, R134a, R513A, R450A, R515B and R515A are A1 (nonflammable) fluids. R450A and R516A also have temperature glides of 0.4 K and 0.056 K, respectively, which can affect condenser design. In terms of equipment modification (sizing), R513A require fewer modifications

ReseArch with Patient and Public invOlvement: a RealisT evaluation - the RAPPORT study

Background Patient and public involvement (PPI) is a prerequisite for many funding bodies and NHS research ethics approval. PPI in research is defined as research carried out with or by the public rather than to, about or for them. While the benefits of PPI have been widely discussed, there is a lack of evidence on the impact and outcomes of PPI in research. Objectives To determine the types of PPI in funded research, describe key processes, analyse the contextual and temporal dynamics of PPI and explore the experience of PPI in research for all those involved. Mechanisms contributing to the routine incorporation of PPI in the research process were assessed, the impact of PPI on research processes and outcomes evaluated, and barriers and enablers to effective PPI identified. Design A three-staged realist evaluation drawing on Normalisation Process Theory to understand how far PPI was embedded within health-care research in six areas: diabetes mellitus, arthritis, cystic fibrosis, dementia, public health and learning disabilities. The first two stages comprised a scoping exercise and online survey to chief investigators to assess current PPI activity. The third stage consisted of case studies tracked over 18 months through interviews and document analysis. The research was conducted in four regions of England. Participants Non-commercial studies currently running or completed within the previous 2 years eligible for adoption on the UK Clinical Research Network portfolio. A total of 129 case study participants included researchers and PPI representatives from 22 research studies, and representatives from funding bodies and PPI networks