University of Missouri--Columbia Research Reactor (MURR) flux trap design using Fluent Computational Fluid Dynamics (CFD)

Abstract only availableThe University of Missouri--Columbia Research Reactor Center (MURR) is the center of a world class, totally unique environment for the research, development, and production in major advances in nuclear medicine. The reactor operates at a ten megawatt power level. Samples are placed in three strategically positioned canisters situated in the flux trap zone of the nuclear reactor core. Heat is removed from the core by water flowing through it, as well as through the flux trap. The trap consists of three vertical cylinders 4 meters long which are encased inside one bigger cylinder, inside every cylinder there is one canister, where the samples are placed. Pool water at a high mass flow rate is pumped inside and around the cylinders to partially cool the reactor core (the main portion of the flow is directly through the core). The purpose of the research is to model the MURR using Fluent Computational Fluid Dynamics (CFD) software, to visually project the pool water flow and heat transfer in the flux trap to enable possible improved positioning of the irradiation samples. In other words, our focus is on being able to create a model of MURR, and understand the effects of geometry in the flux trap for the pool water flow to the fullest extent possible. In conclusion, the geometry of the MURR flux trap has been successfully modeled using GAMBIT, in addition water velocity, temperature, pressure and turbulence have also been successfully computed using FLUENT. The results show regions of high turbulence, strain and velocity in the flux trap. For Future work it will be useful to obtain functional data so these computer results can be verified, also the model that we have constructed should be improved to include all details of the reactor, and finally, the model should be further used to optimize the flow geometry and canister placement of the reactor.Louis Stokes Missouri Alliance for Minority Participatio

Production of nano particles

Abstract only availableNano particles (particles having diameters in the nanometer range) have applications in a variety of areas including medical, environmental, sensor, to name a few. However, the production of nano particles having uniform size and properties is challenging. A number of methods have been proposed for production of nano particles such as flame synthesis, aersol decomposition using indirect heating, and laser ablation. In this work we used a flame synthesis process to produce nano particles of aluminum oxide (Al2O3). Aluminum oxide is used in ceramic industry. The nano size particles can change various mechanical and physical properties of Al2O3 based materials significantly. Two different precursor salts were used for production of Al2O3. The first one was aluminum nitrate-nano hydrate (Al(NO3)3*9H2O) of different concentrations and the other one was aluminum acetate basic (C2H3O2)2AlOH. An aqueous solution of these salts flowed through a mini-mist nozzle and the resulting spray was decomposed in a methane-air flame to produce the particles. Different concentrations of aluminum nitrate and nozzle sizes were used to investigate their effect on the particle size. The particles were analyzed using a scanning electron microscopy (SEM) that showed particles with different sizes, shape and having a porous surface. Although particles in the nano size range were produced, some particles were also in the micron size range. The precursor salt also had significant effect on the particle morphology.Nuclear Science and Engineering Institute (NSEI

Fundamental Understanding of Pebble Bed Nuclear Reactors for Environmentally Benign and Risk Free Proliferation 4th Generation Nuclear Energy and Hydrogen Production [abstract]

Abstract only availableTrack I: Power GenerationPebble bed nuclear reactor is among the 6 suggested 4th generation nuclear reactors. It is also one of the advanced high temperature gas nuclear reactors (AGRs). In such reactor the pebbles that contain the nuclear fuel particles (TRISO) (~900-950 micron) move downward while high temperature helium moves upward. These pebbles are circulated until they are spent. The pebble bed nuclear reactors are characterized as environmentally benign, risk free proliferation with high thermal efficiency (about 55% while the current nuclear reactor technology provides ~ 35%). The fundamental understanding of these reactors is lacking. Therefore, this work as a part of the research program on high temperature reactors through the consortium consists of University of Missouri - Columbia, Missouri S&T, North Carolina State University focuses on the detailed hydrodynamics of the pebbles movement, gas dynamics and heat transfer using both advanced measurement and computation techniques. The progress made on this project at Missouri S&T will be presented and the future work will be outlined

Improved outcomes in the treatment of post-myocardial infarction ventricular septal defect with percutaneous TandemHeart left ventricular mechanical circulatory support

Background Post-myocardial infarction (MI) ventricular septal defect (VSD) is associated with 40% - 50% of peri-procedural mortalities; however, it is amenable to catheter-based therapies. We retrospectively investigated the impact of state-of-the-art bridging percutaneous left ventricular mechanical circulatory support (MCS) using the TandemHeart® (TH) ventricular assist device (VAD) on a patient with post-MI VSD. Results From July 2008 to March 2014, 23 patients were referred for treatment of post-MI VSD. Initially, 18/23 patients required MCS; 12 received an intra-aortic balloon pump (IABP), while 6 received initial TH support. Seven of the IABP patients later required TH support. Catheter-based device VSD closure was performed in 18 of the patients; however, three patients required conversion to conventional open cardiac surgical repair via VSD patch closure due to failure of the catheter-based approach. Five patients with TH underwent planned open cardiac surgical repair due to an anticipated lack of suitability for catheter-based treatment. Results revealed that delayed closure after MI correlated with improved survival. Overall, 30-day and 6-month survival rates were 83% (19/23) and 70% (16/23), respectively. Conclusions Further, Qp/Qs ratios of \u3c2.4 correlated with successful percutaneous VSD repair, and this assessment should be further explored as an assessment to inform clinical judgment in patients with post-MI VSD treatment

Albuterol metered dose inhaler performance under hyperbaric pressures

Comparative Medicine - OneHealth and Comparative Medicine Poster SessionINTRODUCTION: The stimulus for this presentation was an asthma attack suffered on the first dive by a victim of a severe industrial electrical burn. The patient's response to albuterol metered dose inhaler (MDI) treatment given at depth was felt to have been poor. We thus wondered what the output of these devises (chlorofluorocarbon or CFC) was at therapeutic depth versus normobaria. As the current MDIs were being phased out of use we also wondered what the comparable output characteristics of the replacement MDIs (hydrofluoroalkane or HFA) would be. MATERIALS AND METHODS: The dose and aerosol particle size and number delivered by MDIs were measured in a hyperbaric chamber at pressures ranging from one atmosphere absolute (1 ATA, 0 feet of seawater, fsw, 101 kPa) to three ATA (66 fsw, 304 kPa). Mass delivered was measured by a Sartorius B120 analytical balance, and particle size analysis by a TSI 3080L electrostatic classifier with a TSI 3776 ultrafine condensation particle counter. RESULTS: Dose delivery per actuation by CFC and long canister HFA powered MDIs was 13±1% and 12±1% less, respectively, at 3 ATA compared to 1 ATA. However, dose delivery by short canister HFA MDIs was not significantly changed with pressure. The geometric mean diameters of nano particles from the CFC and short canister HFA MDIs decreased from 50 nm at 0 fsw to 32 nm at 66 fsw whereas the long canister HFA aerosol diameters were not affected. The numbers of nanometer size particles delivered at 66 fsw were only 4-7% of those delivered at 0 fsw for the CFC and long canister HFA MDIs; whereas for the short canister HFAs it was 26%. CONCLUSIONS: The doses of albuterol and the sizes and numbers of aerosol particles emitted from albuterol MDIs actuated in a hyperbaric environment vary by canister type; CFC MDI loss is probably unimportant

A Research Program on Very High Temperature Reactors

Track I: Power GenerationIncludes audio file (27 min.)Prismatic and pebble bed very high-temperature reactors (VHTRs) are very attractive both from a thermodynamic efficiency viewpoint and hydrogen-production capability. This project addresses numerous challenges associated with the fuel cycle, materials, and complex fluid dynamics and heat transfer. The objectives of the project are to: i. Conduct physical experiments for fission product transport phenomena in the overcoating and compact structural graphite and transport through TRISO coating layers; ii. Develop improved sorption measurement techniques to measure the accumulation of condensable radionuclides (“plateout”) in the VHTR primary coolant circuit and obtain representative data; iii. Develop advanced computations of charged, radioactive dust (aerosol) transport in the VHTR coolant circuit and confinement by exploring direct simulation Monte Carlo (DSMC) techniques for deposition and resuspension and conduct experiments to verify computational predictions; iv. Develop a program to measure emissivity for various VHTR component materials, both bare and oxidized, and obtain extensive data; v. Develop an experimental program to characterize gas, fission product, and particle flows in the complex geometries of pebble bed modular reactors (PBMRs) and help improve computational approaches and computer programs through experimental understandings. This project is leading to research training of about a dozen Ph D students at the participating universities. Upon graduation, these students will be able to contribute even more effectively to the future challenges in the global deployment of nuclear power generation and hydrogen technologies. We will discuss the VHTR technology and research challenges. We also describe progress on the project by the three Consortium participants

The impact of pay-for-percentile incentive on low-achieving students in rural China

In some accountability regimes, teachers pay more attention to higher achieving students at the expense of lower achieving students. The overall goal of this study is to examine, in this type of accountability regime, the impacts of a pay-for-percentile type scheme in which incentives exist for all students but which are larger for improving the achievement of lower achieving students. Analyzing data from a large-scale randomized experiment in rural China, we find that incentives improve average achievement by 0.10 SDs and the achievement of low-achieving students by 0.15 SDs. We find parallel changes in teacher behavior and curricular coverage. Taken together, the results demonstrate that incentive schemes can effectively address teacher neglect of low-achieving students

Tracking the effects of COVID-19 in rural China over time

Background: China issued strict nationwide guidelines to combat the COVID-19 outbreak in January 2020 and gradually loosened the restrictions on movement in early March. Little is known about how these disease control measures affected the 600 million people who live in rural China. The goal of this paper is to document the quarantine measures implemented in rural China outside the epicenter of Hubei Province and to assess the socioeconomic effect of the measures on rural communities over time. Methods: We conducted three rounds of interviews with informants from 726 villages in seven provinces, accounting for over 25% of China’s overall rural population. The survey collected data on rural quarantine implementation; COVID-19 infections and deaths in the survey villages; and effects of the quarantine on employment, income, education, health care, and government policies to address any negative impacts. The empirical findings of the work established that strict quarantine measures were implemented in rural villages throughout China in February. Results: There was little spread of COVID-19 in rural communities: an infection rate of 0.001% and zero deaths reported in our sample. However, there were negative social and economic outcomes, including high rates of unemployment, falling household income, rising prices, and disrupted student learning. Health care was generally accessible, but many delayed their non-COVID-19 health care due to the quarantine measures. Only 20% of villagers received any form of local government aid, and only 11% of villages received financial subsidies. There were no reports of national government aid programs that targeted rural villagers in the sample areas. Conclusions: By examining the economic and social effects of the COVID-19 restrictions in rural communities, this study will help to guide other middle- and low-income countries in their containment and restorative processes. Without consideration for economically vulnerable populations, economic hardships and poverty will likely continue to have a negative impact on the most susceptible communities

Cross-Effects in Microgravity Flows

Film growth by chemical/physical vapor deposition is a process of considerable interest in microgravity experiments. The absence of natural convection should allow better control of film growth processes but, in highly non-isothermal ampoules, thermal slip (creep) can become a matter of significant concern. The reported research is a theoretical and experimental investigation of the flow of gas/vapor mixtures under non-continuum conditions. The Boltzmann equation has been solved for a monatomic gas under non-condensing conditions and the various phenomenological coefficients have been computed. Computations for realistic potentials as well as for velocity and creep slip have been completed and the creep slip has been found to be dependent on the type of gas confirming the accuracy of previous variational results. The variational technique has been extended and planar flows calculated via the Burnett solutions. Velocity, diffusion and creep slips have been computed for gas mixtures and previously unknown dependencies of the creep slip on the mixture properties have been observed. Also for gas mixtures, an integral representation of the linearized Boltzmann operator has been developed for use in numerical and variational calculations for all intermolecular force laws. Two, two-bulb capillary systems have been designed, built and tested for the measurements of cross-flows; one of glass for isothermal measurements and one of stainless steel for non-isothermal measurements. Extensive data have been collected for Ar-He and N2-He mixtures at a variety of pressures and mole ratios. Viscosity, velocity slip coefficients and tangential momentum accommodation coefficients have been obtained from measurements with a spinning rotor gauge via a new theory that has been formulated for the spinning rotor gauge in the slip regime. The FIDAP fluid dynamics code has been applied to condensing flows in ampoules in the continuum regime and agreement obtained with the earlier work of Duval

Delayed intracardial shunting and hypoxemia after massive pulmonary embolism in a patient with a biventricular assist device

We describe the interdisciplinary management of a 34-year-old woman with dilated cardiomyopathy three months postpartum on a cardiac biventricular assist device (BVAD) as bridge to heart transplantation with delayed onset of intracardial shunting and subsequent hypoxemia due to massive pulmonary embolism. After emergency surgical embolectomy pulmonary function was highly compromised (PaO2/FiO2 54) requiring bifemoral veno-venous extracorporeal membrane oxygenation. Transesophageal echocardiography detected atrial level hypoxemic right-to-left shunting through a patent foramen ovale (PFO). Percutaneous closure of the PFO was achieved with a PFO occluder device. After placing the PFO occluder device oxygenation increased significantly (Δ paO2 119 Torr). The patient received heart transplantation 20 weeks after BVAD implantation and was discharged from ICU 3 weeks after transplantation