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CNTR Rotating Fuel Tube Turbine Design and Speed Control
Get PDFThe work for this project involves the research, design, and testing of the turbine for a Centrifugal Thermal Rocket (CNTR) that can withstand a 420 day round trip human space expedition in terms of efficiency and vibration to suit the needs of NASA.
The project for Team 02 is to design and improve the turbine in the Nuclear Thermal Propulsion (NTP) system. Improvements from the previous years prototype are focused on vibration issues and materials on all elements of the project.
With performance in high temperature, dynamic fluid motion, and high rotation speeds in mind, the team is developing a prototype. The project also pertains to the issue of startup and shut down. Team 20 from the previous year with a similar project proposal, used an electric motor for startup, although to account for high temperatures, Team 02 is taking an alternative approach. The team developed design concepts pertaining to bearings, motors, turbines, structure, and function. Using Pugh and QFD analysis, these concept ideas were narrowed down using engineering and consumer requirements. CAD models of five different turbines were created and analyzed with ANSYS to determine which design choices would produce the best results.
For a proof of concept, a 3D printed prototype was built along with CFD simulations of the printed and possible turbines. Computational calculations to verify that validity of the design in terms of speed, thermodynamics, fluid flow, blade interaction, vibration, and pressure were also included in the proof of concept. Going forward into the next semester, further research and testing will be performed on each turbine along with improvements on the construction of the assembly
Corrigendum to “Quantification of microplastics in sediments from Narragansett Bay, Rhode Island USA using a novel isolation and extraction method” (Marine Pollution Bulletin (2022) 174, (S0025326X21012881), (10.1016/j.marpolbul.2021.113254))
No full textA) James Farnan was added as a co-author. B) The following chapters must be added at the section: Supplemental Information/The hybrid Extraction method/2. Sediment collections/2.2 Experimental procedure/2.2.4 Density separation: 2.2.4.6 Halfway through the settling period, transfer any settled sediment into a new separatory funnel. Place a new 1-L separatory funnel in upright position and make sure funnel is closed. Slowly open the valve at the bottom of the separatory funnel and empty the sediments into a new separatory funnel. Retain for later use. 2.2.4.7 Allow the sediments in the original separatory funnel to continue settling for the remaining time. The water column should be mostly clear, with the exception of floating debris at the solution surface. 2.2.4.8 If sediment is very fine or has not settled completely, allow to settle for additional time after emptying sediments into a new funnel and before filtering. This could be anywhere from 10 min to 1 h, then empty the settled sediments into the same funnel as 2.4.6. Replace chapter 2.6.3, by the following amended text: Place separatory funnel in ring stand and use remaining 20–100 mL NaBr solution to rinse the inside of the stopper and the inner walls of the separatory funnel. The goal is to remove any debris stuck to the inner wall of the separatory funnel. Let settle for 2 h, or longer until clearly defined water column separates from sediment. Repeat steps 2.2.4.5–2.2.4.8. C) James Farnan has been added to the list of authors for his contribution to the paper and changes made
Groundwater quality: global challenges, emerging threats and novel approaches
No full textImproving our understanding of groundwater quality threats to human health and the environment is essential to protect and manage groundwater resources effectively. This essay highlights some global groundwater quality challenges, describes key contaminant groups and threats of emerging concern, including antimicrobial resistance, and discusses novel approaches to assessing groundwater quality. Groundwater quality monitoring needs to improve significantly in order to effectively identify and mitigate threats to groundwater from historical, current and future pollution
Machine learning guided design of microencapsulated phase change materials-incorporated concretes for enhanced freeze-thaw durability
No full textProlonged exposure to freeze-thaw cycles (FTCs) induces adverse effects in concrete structures in terms of a significant reduction in strength and durability. This paper proposes a microencapsulated phase change material-incorporated concrete (MPCMC) layer to mitigate FTCs in the concrete bridge decks. Toward this, the present work implements finite element analysis (FEA)-based multiscale numerical simulation, which shows the effectiveness of the proposed MPCMC protective layer toward FTC reduction. Moreover, the multiscale framework is leveraged to generate a large dataset containing 8096 data points of FTCs considering a uniform variation of five design parameters, namely the thickness of the protective MPCMC layer, volume fraction, transition temperature, size, and the latent heat of the MPCM. Thereafter, the dataset is leveraged to develop an interpretable neural network (NN)-based predictive model as a computationally efficient alternative to the complex multiscale FEA-based design tools. The interpretable machine learning (ML) model provides a reliable and efficient continuous mapping between the design parameter space and the resultant number of FTCs. Moreover, it explains general engineering intuitions and physics. Besides, the interpretable ML characterizes various underlying interplays of the design parameters in dictating the resultant FTCs
Rheology of saliva in health and disease
No full textBACKGROUND: Saliva is a complex fluid that lubricates the oropharynx and facilitates chewing, swallowing, and vocalization. Viscoelasticity is critical for the ability of saliva to fulfill these functions. Xerostomia, or a sensation of dry mouth, occurs in 17-26% of the population. Although many equate xerostomia with hyposalivation, high-risk patients frequently report oral dryness in the absence of decreased salivary flow. OBJECTIVE: This study aims to determine if xerostomia is associated with alterations in the rheological properties of saliva in addition to decreased salivary production. METHODS: The study population included patients with post-radiation xerostomia, patients with anticholinergic-induced xerostomia and healthy controls. Salivary volumetric flow rate was measured, shear viscosity was measured using oscillatory rheometry, and extensional viscosity was measured using capillary thinning methods. Groups were compared using descriptive statistics and univariate analysis. RESULTS: A total of 36 subjects were included: 15 with post-radiation xerostomia, 9 with anticholinergic-induced xerostomia and 12 controls. Salivary volumetric flow was significantly decreased in post-radiation and anticholinergic-induced patients compared to controls. On capillary thinning testing, saliva from xerostomia patients had significantly greater extensional viscosity compared to controls. However, saliva from the three groups showed no significant difference in the complex viscosity or the storage or loss modulus of saliva with oscillatory rheology. CONCLUSIONS: Xerostomia is associated with decreased salivary volumetric flow and quantitative changes in the rheologic properties of saliva
Parental education in media literacy, social media and Internet safety for children in Bosnia and Herzegovina
Get PDFParents have a great responsibility to protect their children while online, and to make sure that they are using digital technologies in a safe manner; at the same time, parents are not sufficiently educated and are unfamiliar with all regulatory mechanisms and possibilities of controlling and protecting their children online. Children need some help to take advantage of all positive aspects of digital trends and to protect themselves from those which are potentially negative. The international framework in the legal sense, which is in charge of standardizing the protection of the interests and rights of children on the Internet, is put in the focus of the work. It is important to note that the international legal framework is generally valid and binding for the national framework that regulates the same issues in Bosnia and Herzegovina (BiH). The aim of this research is to establish how well parents from BiH are acquainted with the Internet-related regulations and the mechanisms for ensuring Internet safety for their children and to what extent these mechanisms are being applied. The results of this research demonstrate that the majority of parents are not sufficiently familiar with the regulatory mechanisms and that they are not using all available tools to protect their children online
Informing the Development of School-Based Strategies to Promote Children\u27s Executive Function Skills: Considerations, Challenges, and Future Directions
Get PDFIn recent years awareness of the importance of executive function (EF) skills for students\u27 academic growth has increased. Research suggests that experience in school promotes EF development; however, recommendations regarding evidence-based practices that educators can use to support EF in their classrooms are limited. Here we outline two main reasons that this may be the case. First, there are significant challenges in the measurement of EF, which have implications for our understanding of how children use EF skills in support of learning in the moment and in real-world settings like the classroom. Second, there is limited direct research on the types of classroom experiences that promote EF. In describing both, we highlight emerging evidence and new methods that are helping us better understand the development of EF and the ways in which school experiences shape this growth, which will ultimately inform the development of school-based strategies to promote these skills
Hemodynamic Changes with Umbilical Cord Milking in Nonvigorous Newborns: A Randomized Cluster Cross-over Trial
No full textObjective: To assess the hemodynamic safety and efficacy of umbilical cord milking (UCM) compared with early cord clamping (ECC) in nonvigorous newborn infants enrolled in a large multicenter randomized cluster-crossover trial. Study design: Two hundred twenty-seven nonvigorous term or near-term infants who were enrolled in the parent UCM vs ECC trial consented for this substudy. An echocardiogram was performed at 12 ± 6 hours of age by ultrasound technicians blinded to randomization. The primary outcome was left ventricular output (LVO). Prespecified secondary outcomes included measured superior vena cava (SVC) flow, right ventricular output (RVO), peak systolic strain, and peak systolic velocity by tissue Doppler examination of the RV lateral wall and the interventricular septum. Results: Nonvigorous infants receiving UCM had increased hemodynamic echocardiographic parameters as measured by higher LVO (225 ± 64 vs 187 ± 52 mL/kg/min; P \u3c.001), RVO (284 ± 88 vs 222 ± 96 mL/kg/min; P \u3c.001), and SVC flow (100 ± 36 vs 86 ± 40 mL/kg/min; P \u3c.001) compared with the ECC group. Peak systolic strain was lower (−17 ± 3 vs −22 ± 3%; P \u3c.001), but there was no difference in peak tissue Doppler flow (0.06 m/s [IQR, 0.05-0.07 m/s] vs 0.06 m/s [IQR, 0.05-0.08 m/s]). Conclusions: UCM increased cardiac output (as measured by LVO) compared with ECC in nonvigorous newborns. Overall increases in measures of cerebral and pulmonary blood flow (as measured by SVC and RVO flow, respectively) may explain improved outcomes associated with UCM (less cardiorespiratory support at birth and fewer cases of moderate-to-severe hypoxic ischemic encephalopathy) among nonvigorous newborn infants
