A STUDY OF SOLID CO2 FORMATION FROM RAPID FLUID EXPANSION USING CFD AND MATHEMATICAL MODELLING

Rapid carbon dioxide expansion from an accidental pipeline leakage is an adiabatic process that forms solid CO2 micro-particles entrained in CO2 vapor. While the vapor is subsequently dispersed as vapor cloud, the micro-particles – at sizes larger than 100 μm – can rain out to form a solid pool. The pool will then sublimate to the atmosphere and contribute significantly to the concentration of vapor cloud. Ultimately, the effect of solid rainout pool on vapor cloud concentration and dispersion has to be taken into consideration when calculating safety distance. In order to investigate the sizes of solid micro-particles formed under varying discharge scenarios, the process of rapid fluid expansion through an orifice (leakage) is emulated using a simulation model. It involves an integration of two sub-models: (1) a 3-D Computational Fluid Dynamics (CFD) model using FLUENT 14.0, and (2) a mathematical model published by authors Hulsbosch-Dam, Spruijt, Necci & Cozzani (2012). The CFD model employs the FLUENT software to obtain temperature and velocity profiles of rapid fluid expansion. The mathematical model calculates the droplet size distribution from the point of release and size of final solid particles formed. The combination of the two models generates results and parametric trends (mainly the effect of leakage size on the size of particles formed). They are then compared with experimental data available in literatures, and validation is achieved. Finally, the model is used to simulate rapid carbon dioxide expansion from pipeline leakage at supercritical storage conditions. Conclusive evidence shows that at supercritical storage conditions (specifically at 310 K and 150 bar), a pipeline leakage will not produce solid CO2 micro-particles big enough to form a solid rainout pool

Bacteremia Associated with Early Childhood Caries

Previous research has investigated the post-operative bacteria levels caused by a variety of clinical procedures such as anesthetic injections, standard dental procedures, endodontic treatment, periodontal surgery, root scaling, and oral surgical procedures in children. Other studies have suggested that bacteremias are often caused by oral infections. Although numerous studies have examined how oral infections lead to various medical conditions (i.e. brain abscess) none have studied the potential for preoperative bacteremia that may arise in conjunction with early childhood caries (ECC). The purpose of this study was to compare potential systemic facultative and anaerobic bacteria found in otherwise healthy children who had type III early childhood caries to children who were caries free. METHODS AND MATTERIALS Twenty patients diagnosed with severe ECC and presenting for a complete oral-dental rehabilitation at Loma Linda University Surgery Center for Dentistry were selected as subjects for this study. After obtaining informed consent from each patient, 5ml of blood was drawn from the patient immediately after the intravenous line had been initiated. The blood was analyzed for bacteria levels by clinical laboratory using an automated Bactec® blood culturing system. The results were to be compared with a control group that was composed of healthy patients and did not have ECC, however, due to ethical issues raised by the Universities Institutional Review Board a control group was not included in this study. Instead, data from the literature similar to the control group was used. This is discussed in detail in the methods and materials of the thesis. RESULTS One subject (5%) was identified as having Staphylococcus saprophyticus. No bacteremias were cultured from the remaining nineteen subjects. Thus 95% of the experimental group demonstrated no bacteremia. CONCLUSIONS Nineteen out of twenty children in the experimental group (95%) showed no evidence of preoperative bacteremia. One out of twenty children in the experimental group (5%) showed a bacteremia identified as Staphylococcus saprophyticus, a common skin contaminant. There was no statistically significant difference between the experimental and control group. Further research is indicated on children being treated for ECC to determine the specific procedures that initiate bacteremia

A STUDY OF SOLID CO2 FORMATION FROM RAPID FLUID EXPANSION USING CFD AND MATHEMATICAL MODELLING

Rapid carbon dioxide expansion from an accidental pipeline leakage is an adiabatic process that forms solid CO2 micro-particles entrained in CO2 vapor. While the vapor is subsequently dispersed as vapor cloud, the micro-particles – at sizes larger than 100 μm – can rain out to form a solid pool. The pool will then sublimate to the atmosphere and contribute significantly to the concentration of vapor cloud. Ultimately, the effect of solid rainout pool on vapor cloud concentration and dispersion has to be taken into consideration when calculating safety distance. In order to investigate the sizes of solid micro-particles formed under varying discharge scenarios, the process of rapid fluid expansion through an orifice (leakage) is emulated using a simulation model. It involves an integration of two sub-models: (1) a 3-D Computational Fluid Dynamics (CFD) model using FLUENT 14.0, and (2) a mathematical model published by authors Hulsbosch-Dam, Spruijt, Necci & Cozzani (2012). The CFD model employs the FLUENT software to obtain temperature and velocity profiles of rapid fluid expansion. The mathematical model calculates the droplet size distribution from the point of release and size of final solid particles formed. The combination of the two models generates results and parametric trends (mainly the effect of leakage size on the size of particles formed). They are then compared with experimental data available in literatures, and validation is achieved. Finally, the model is used to simulate rapid carbon dioxide expansion from pipeline leakage at supercritical storage conditions. Conclusive evidence shows that at supercritical storage conditions (specifically at 310 K and 150 bar), a pipeline leakage will not produce solid CO2 micro-particles big enough to form a solid rainout pool

Synaptic Innervation Density Is Regulated by Neuron-Derived BDNF

AbstractIn this report, we have examined the role of neuron-derived BDNF at an accessible synapse, that of preganglionic neurons onto their sympathetic neuron targets. Developing and mature sympathetic neurons synthesize BDNF, and preganglionic neurons express the full-length BDNF/TrkB receptor. When sympathetic neuron-derived BDNF is increased 2- to 4-fold in transgenic mice, preganglionic cell bodies and axons hypertrophy, and the synaptic innervation to sympathetic neurons is increased. Conversely, when BDNF synthesis is eliminated in BDNF −/− mice, preganglionic synaptic innervation to sympathetic neurons is decreased. Together these results indicate that variations in neuronal neurotrophin synthesis directly regulate neuronal circuitry by selectively modulating synaptic innervation density

An Early Diagnosis of Oral Cancer based on Three-Dimensional Convolutional Neural Networks

Three-dimensional convolutional neural networks (3DCNNs), a rapidly evolving modality of deep learning, has gained popularity in many fields. For oral cancers, CT images are traditionally processed using two-dimensional input, without considering information between lesion slices. In this paper, we established a 3DCNNs-based image processing algorithm for the early diagnosis of oral cancers, which was compared with a 2DCNNs-based algorithm. The 3D and 2D CNNs were constructed using the same hierarchical structure to profile oral tumors as benign or malignant. Our results showed that 3DCNNs with dynamic characteristics of the enhancement rate image performed better than 2DCNNS with single enhancement sequence for the discrimination of oral cancer lesions. Our data indicate that spatial features and spatial dynamics extracted from 3DCNNs may inform future design of CT-assisted diagnosis system

Advanced Television and Signal Processing Program

Contains an introduction and reports on two research projects.Advanced Television Research Progra

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Advanced Television and Signal Processing Program

Contains an introduction and reports on fifteen research projects.Advanced Television Research ProgramAdams-Russell Electronics, Inc.National Science Foundation Fellowship Grant MIP 87-14969National Science Foundation FellowshipU.S. Navy - Office of Naval Research Grant N00014-89-J-1489U.S. Air Force - Electronic Systems Division Contract F1 9628-89-K-004