Three dimensional thermal analysis of rocket thrust chambers

A numerical model for the three dimensional thermal analysis of rocket thrust chambers and nozzles has been developed. The input to the model consists of the composition of the fuel/oxidant mixture and flow rates, chamber pressure, coolant entrance temperature and pressure, dimensions of the engine, materials and the number of nodes in different parts of the engine. The model allows for temperature variation in three dimensions: axial, radial and circumferential directions and by implementing an iterative scheme, it provides nodal temperature distribution, rates of heat transfer, hot gas and coolant thermal and transport properties

Observing and modeling drivers’ behavior in work zones using SHRP 2 naturalistic driving study data

The presence of a work zone increases disturbances to traffic flow and produces high cognitive workloads for drivers, which can increase the safety risks. There was an increase of about 11% in work zone-related fatalities from 2010 to 2014 despite a small decrease in non-work zone-related fatalities in the U.S. A number of studies concluded speeding and distractions are the main unsafe driver behaviors contributing to work zone crashes. Federal Highway Administration (FHWA) crash facts indicated speeding as a contributing factor for 28% of work zone crashes in 2014. A series of countermeasures have been used to get drivers’ attention to comply with work zone conditions. There is limited information about which safety features are the most effective in accomplishing this goal. The effectiveness of safety features can sometimes vary due to driver behavior that has not been truly investigated due to limited information in our traditional crash data. The Naturalistic Driving Study (NDS) data, developed by the Strategic Highway Research Program (SHRP) 2 provides a unique opportunity to observe actual driver behavior, to identify main contributing factors associated with crashes and near-crashes, and to understand how drivers negotiate work zones. The aim of this dissertation is to develop models that provide a better understanding of driver behavior in work zones. The additional objective is to determine the most effective safety features to get drivers’ attention in reducing their speed in work zones. The task was accomplished by conducting three studies. The first paper developed a logistic regression model using a number of explanatory variables which included driver behavior, work zone characteristics, and environmental conditions to predict the crash/near-crash event outcome. In the second paper, the speed trajectory time series data were used to develop models to accurately and efficiently estimate the location of changepoint in mean speed reacting to safety features utilized in work zones to encourage safe driving. The final paper utilized the methods of functional data analysis to understand and analyze driver behavior interacting with safety features applied in work zone with various characteristics. The methods were used to identify the effectiveness of various safety features

Investigating the crash interaction of younger and older (Y-O) drivers

Many studies have identified that older (O) and younger (Y) drivers are the most at risk age groups on U.S. highways; however, little information is available on the interaction of the cohorts. It would seem that the characteristics that make the two groups most risky would be compounded in situations where the two types of drivers meet on the road. As expected, statewide analysis of Y-O crashes, using VMT as a sole measure of exposure, reveals over-representation; however, when adjusted for over-involvement of Y-O drivers as groups, Y-O crashes are actually under-represented. Causal factors such as passenger load and type of roadway geometry are also investigated. Spatial and temporal variation of Y-O crashes reveal that some Iowa counties are over-represented and that 3:00-4:00 p.m. is the most represented hour for Y-O crashes

Dark Matter directional detection: comparison of the track direction determination

Several directional techniques have been proposed for a directional detection of Dark matter, among others anisotropic crystal detectors, nuclear emulsion plates, and low-pressure gaseous TPCs. The key point is to get access to the initial direction of the nucleus recoiling due to the elastic scattering by a WIMP. In this article, we aim at estimating, for each method, how the information of the recoil track initial direction is preserved in different detector materials. We use the SRIM simulation code to emulate the motion of the first recoiling nucleus in each material. We propose the use of a new observable, D, to quantify the preservation of the initial direction of the recoiling nucleus in the detector. We show that in an emulsion mix and an anisotropic crystal, the initial direction is lost very early, while in a typical TPC gas mix, the direction is well preserved.Comment: 9 pages, 5 figure

Mobile phone-based evaluation of talent tuberculosis infection

The tuberculin skin test (TST) is the most widely used method for detecting latent tuberculosis (TB) infection (LTBI) in adults and active TB disease in children. This work presents the development of a screening tool to detect LTBI's, which works in conjunction with the TST and serves as an alternative for measuring the TST induration. The screening tool makes use of a mobile application developed on the Android platform to capture images of an induration, and photogrammetric reconstruction using Agisoft PhotoScan to reconstruct the induration in 3D, followed by 3D measurement of the induration with the aid of Python functions. The screening accuracy of the developed process was tested using a 3D printed induration and an HTC One smartphone to capture images. In this accuracy test, the developed screening tool was found to measure indurations more accurately than current measurement methods, as indicated by the lower standard deviation produced. An experiment to simulate real-world conditions was conducted by using the developed screening tool on a set of mock skin indurations, created by a make-up artist, and evaluating its performance. It was found that the height of the skin induration and definition of its margins are the most significant factors that influence the accuracy of the screening tool under simulated real-world conditions. Future work should explore possible improvements to the developed image capture protocol and the bimodal segmentation methods employed in this project

Women, peace and security in the time of corona

With over 70% of the global healthcare workforce made up of women and many more shouldering caregiving roles, women are at the forefront of the fight against COVID-19, but the consequences and new realities of our world have gendered implications that need to be understood. Sanam Naraghi Anderlini MBE calls our attention to these impacts, the realities of women living this pandemic, and the relevance of the women, peace and security agenda now more than ever