Sensitivity to Heavy Neutral Leptons with the SAND detector at the DUNE ND complex

Heavy Neutral Leptons (HNLs) have been an interesting topic for experimental particle physics in the past few years. A study has been performed within the framework of the multi-instrument DUNE near detector complex, specifically regarding the on-Axis System, to assess the sensitivity to HNL within six years of exposure. By utilizing two MC generators, and charmed heavy meson decay channels, the sensitivity to HNL masses between 0.3 and 1.8 GeV/$c^2$ has been explored. A Mad-Graph/Mad-Dump model has been implemented based on the $\nu MSM$ Lagrangian, and used to obtain accurate kinematics for the decay of mesons and HNL. The simulated final-state particles have been propagated through the detector; a track reconstruction algorithm, based on the Kalman Filter technique, along with a simple two-body decay selection, is implemented to estimate efficiency and background rejection. The HNL sensitivity has been estimated both from purely phenomenological as well as experimental point of view, reaching O($10^{-9}$) for higher HNL masses, with about a factor 3 deterioration between the phenomenological and the experimental case. In this paper, the results for direct and indirect decay channels of charmed meson $D_s$ to HNL has been investigated and the potential for further improvements has been discussed.Comment: General revisio

Flow boiling heat transfer characteristics of R245fa refrigerant in a plate heat exchanger

Plate heat exchangers (PHEs) are used extensively in industrial applications and, owing to their compactness, and higher thermal efficiency, they are keys component of organic Rankine cycle (ORC) application. This study presents the experimental heat transfer characteristics during flow boiling of R245fa refrigerant with a commercial working fluid used in ORCs; inside brazed plate heat exchanger with chevron angle of 65 degree. The flow boiling heat transfer characteristics were measured with varying saturation temperatures, mass flux and heat flux, which range from 55.5 \ub0C-61.8 \ub0C, 15.5-17.4 kg m-2 s-1, and 6400-10120 W m-2, respectively. The experimental results showed that flow boiling heat transfer coefficient is dependent upon the heat flux and mass flux. The results showed that the heat transfer coefficient increases with the increase of heat flux, and then starts to decrease due to local dry out. However, at low mass flux, locally triggering dry out was more prominent than that high mass flux. The heat transfer coefficient showed to be sensitive to the change in the saturation temperature. Moreover, flow boiling heat transfer coefficient showed a linear relationship with mass flux of the refrigerant

A Study on Gas Evolving Electrodes under Extreme Current Densities

ABSTRACT A Study on Gas Evolving Electrodes under Extreme Current Densities Zahra Ghorbani Electrochemical discharges or electrode effects are used in different fields such as micro-machining, nano-particle production, and surface engineering. Further development and improvement of the different applications of electrochemical discharges require a better understanding of this process. Beyond the critical voltage, an insulating gas film forms around the electrode and discharges take place through the gas film. The stability of the gas film affects the quality of the discharges. The gas film formation is therefore investigated in the present thesis. The main objective of the current project is to attain a better insight into the gas film dynamics. This goal is achieved through the following approaches: 1. The current-voltage characteristics are studied prior to the gas film formation and then compared with a model developed based on the percolation theory. 2. Since the hydrodynamic forces define the shape and thickness of the gas film, the effect of the hydrodynamic parameters on a gas film are analyzed. Based on the Pi theorem and dimensional analysis, important dimensionless parameters are derived to investigate the gas film formation. 3. Different system configurations are examined to improve the electrochemical discharge activity. Visual observations indicate that stable discharges are obtained by using a covered electrode and applying an offset pulsed voltage. Key words: Electrochemical discharges, Gas film formation time, Gas film thickness, Gas bubble evolutio

Oil Spill Detection Using Deep Neural Networks

Oil spills have catastrophic effects on the environment, wildlife, economy, and human health. Therefore, timely detection of oil spills can reduce these disastrous impacts. Existing oil spill detection practices include in-situ (e.g., acoustic method, vapor sampling, pressure-point-analysis, and negative pressure wave) and remote sensing methods (e.g., traditional image processing and image processing using artificial intelligence). These methods rely mostly on skilled personnel for data collection, processing, and analysis, thus leading to slow, costly, and subjective results. Furthermore, oil platforms and pipelines are often situated in remote, harsh areas, making inspections hazardous. To remedy this problem, in this Thesis, three state-of-the-art artificial intelligence (AI) models, namely VGG16, YOLOv3 (you-only-look-once), and mask R-CNN (mask region-based convolutional neural network) are used in a transfer learning scheme to facilitate the process of detecting oil spills and surrounding objects such as vessels and oil rigs. Keyword search, a semi-supervised machine learning approach, is used to collect red-green-blue (R-G-B) imagery for training and testing these models. The methodology includes image classification, object detection, and instance segmentation. The VGG16 model is used to predict the existence of an oil spill in an image, yielding an accuracy of 93%. The YOLOv3 model is implemented to detect and mark the location of vessels and oil rigs. The mean average precision for detecting these two object classes is 61.5% (46% for vessel and 77% for oil rig). The mask R-CNN model is utilized to identify oil spill boundaries at the pixel level in the input image. Results (considering all test images) indicate an average precision of 62%, and an average recall of 71%. Findings of this Thesis are sought to benefit oil and gas industry stakeholders and coastal communities by creating operational AI-assisted technologies for timely detection and response to oil spills and other environmental pollutions, ultimately contributing to human health, environment preservation, and profitability of energy exploration projects

Perceived oral health among adults in Tehran, Iran; a telephone survey

Objective: In comparison to clinical oral health indices, perceived oral health measures are less applied in large-scale epidemiological oral health studies in Iran. The aim of this study was to measure perceived oral health among adults in Tehran, Iran.Methods: In this cross-sectional study, perceived oral health was measured in 1100 adults in Tehran by two measures: 1- non-replaced extracted teeth, and 2- revised Rand dental health questions including pain, chewing problems and communication problems. Data was gathered by telephone interview using gender, age and level of education as socio-demographic information.Results: The mean number of non-replaced extracted teeth was 1.28 with 53.8% of adults reporting no extracted teeth. Extracted teeth was significantly less in younger (p<0.001) and more educated people (p<0.001). Rand dental health scores increased by age (p<0.001) but had no significant changes in different educational levels. The three items of Rand dental health were highly correlated (p<0.01) with Chronbach’s Alpha=0.73 but were not correlated with extracted teeth.Conclusion: Approximately half of Tehran adults have the experience of lacking one or more teeth, with a small group of them suffering from pain, chewing problems and communication problems

Self-Reported Dental Public Health Competencies of Senior Dental Students: A Cross-Sectional Study

Objective: To reach the World Health Organization's goal of improving community oral health, Iranian oral health policy-makers expanded the scope of oral health by including dental public health (DPH) courses in the latest dental curriculum to improve students' competencies. The aim of the current study was to evaluate DPH competencies in senior dental students at Shahid Beheshti University of Medical Sciences, according to specified educational objectives. Methods: In the present cross-sectional study, 195 senior dental students (enrolled in 2014-2015) filled up an online standardized questionnaire. The instrument included demographic information as well as 31 statements about ten domains of DPH. Participants used self-assessment method to report the level of their competencies on a Likert scale of 0-10; Zero indicating "not competent at all", and 10 indicating "fully competent" for each statement. Then the mean score was calculated for each domain. Data analysis was conducted using Independent samples, T-test, One-way ANOVA, Mann-Whitney U-test, and Kruskal-Wallis via SPSS version 21. ResultsThe sum of scores for each participant was within the range of 63 to 310, and the mean (SD) was 216.68 (±43.69). Students were most competent in "Providing preventive dental care" (8.22±1.59), "Adherence to professional ethics" (7.56±1.68), and" Understanding determinants of oral health" (7.50±1.52). They were least competent in "Understanding components and functions of healthcare system" (5.96±2.06), "Planning" (6.06±2.45), and "Oral health research" (6.24±2.44). The mean score for females' (223.30±38.21) was significantly higher than males' score (207.15±49.25), (P=0.011). Conclusion: Although higher competencies were achieved in "Providing preventive dental care", "Adherence to professional ethics", and" Understanding determinants of oral health"; there are more areas to be accomplished, such as "Understanding components and functions of healthcare system", "Planning", and "Oral health research". These findings could be helpful either in revising the content materials, teaching methods, or both

Comparative Effectiveness of Cognitive-Behavioral Therapy and Dialectical Behavior Therapy on Emotion Regulation, Positive and Negative Affection, Aggressive and Self-Harm Behaviors of 13-16-Year-Old Female Students

This study was aimed to compare the effectiveness of cognitive-behavioral therapy with dialectical behavior therapy on emotion regulation, positive and negative affection, aggressive and self-harm behaviors of 13 to 16-year-old female students. The results showed that both CBT and DBT have a significant effect on increasing emotional regulation and positive affect, and decreasing negative affect, reducing aggressive behavior and self-harm. Also there was no significant difference between two treatments in increasing the positive affection and decreasing negative affection, but the effect of DBT on increasing emotional regulation and reducing self-harm and aggressive behaviors was significantly more than CBT

Comparison of tooth brushing related knowledge, attitude and health behavior as well as dental health status among boy and girl students in elementary schools in district 4 of Tehran in 2015

Background and aims: Assessment of oral health status is considered as one of the main criteria for evaluating the public health. Knowledge and attitude towards oral health behavior, especially brushing and gender differenceare factors influencing oral health. This study was aimed to compare tooth brushing related knowledge, attitude and health behavior as well as …. (DMFT) among girl and boy students in elementary schools in district 4 of Tehran in2015.Method: The present cross-sectional (descriptive and analytical) study was carried out among 408 girl and boy elementary students from six randomly selected schools in district 4 of Tehran, Iran. Two-stage cluster sampling was selected and employed. A valid and reliable researcher-… questionnaire was used for this study. Dental visits wereperformed on the basis of DMFT index and all students were assured of information confidentiality. The data were analyzed using SPSS (version 16) software.Results: In the current study, comparing female students with males showed that the mean scores of brushing knowledge, attitude and health behavior in girls was higher than boys and the difference was statistically significant (p=0.001). However, the observed mean DMFT difference between the girls and boys in this study was not significant (p>0.05). Furthermore, a strong and statistically significant relationship was noticed between frequency of brushing and DMFT in both sexes (p<0.05).Conclusion: Mean scores of knowledge, attitude and behavior in both sexes were fairly good and also better in female students than males. It was further found that boys and girls in our study can be, respectively, classified as low and very low mean DMFT groups based on World Health Organization classification. Therefore, appropriate educational interventions with more focus on the vulnerable group of boys are highly advocated in order to improve their knowledge and attitude. Key Words: Knowledge, Attitude, DMFT, Health behavior brushin