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Environmental Effects on Viable Virus Transport and Resuspension in Ventilation Airflow
Get PDFCurrently little is known on how SARS-CoV-2 spreads indoors and its infectability. The objective of this study is to gain more knowledge on the effect of environmental factors on the spread and infectivity of virus aerosols in the built environment. Understanding how the virus transmits indoors would allow for early detection and mitigation of viral particles in room sized spaces. Bovine coronavirus (BCoV) was used as virus simulant in laboratory experiments conducted in a controlled humidity cabinet at Biosafety Level 2. An air-jet nebulizer was used to disseminate known numbers of BCoV particles. After aerosolization, the surface in the cabinet was swiped at regular time intervals to assess the number of particles impacted. Additional surfaces placed in the chamber and swiped at the end of testing. The samples were quantified using quantitative polymerase chain reaction (qPCR). Virus attachment to the surfaces was analyzed using bio-layer interferometry. The virus aerosols that remained suspended in the air were collected bioaerosol collectors with a reference air sampler and quantitated by qPCR. To monitor the effect of the ventilation on the virus movement, PRD1 bacteriophage aerosols as virus simulants were also disseminated in a �� scale ventilated hospital test room equipped with twelve PM2.5 samplers at 15 L/min. After plating and counting the plaque forming units (PFU), the highest concentration of viral particles was detected above the patient���s head in the test room in the second ventilation configuration. Other high virus concentration locations were near the foot of the patient���s bed. From these results, it was determined that with the current airflow set up in the second configuration with the air inlet on the ceiling above the bed, exhaust bottom left on the wall behind the bed, the virus particles concentrate over the lower part of the patient���s bed. Based on air property measurements, aerosol collections and the mechanical blueprint of the model room, a computational flow model was created to visualize the entrainment and movement of the virus in the ventilation airflow. The models showed the third presented configuration minimized particle concentration at the door while the first configuration decreased overall particle concentration in the room
Meteotsunamis Characterization for Gulf of Mexico and Development of a Low Power Autonomous Surface Vehicle Using a Moving-Mass-Actuated Stabilizer Hydrofoil Concept
No full textRecently, there has been an increasing awareness and research relating to meteotsunamis (MT). MTs are caused by atmospheric disturbances (AD) such as cold fronts, squalls, and storms. One of the well-established causes of MT is Proudman Resonance when the AD forward speed matches the wave celerity in its path. In this work, an AD model that was developed previously has been used along with depth-integrated Navier Stokes equations to conduct 34,560 numerical experiments in the Gulf of Mexico.
The data generated thus has been analyzed using a newly developed characterization tool -the meteotsunami rose chart. A description is provided on how MT rose charts are to be read. A sensitivity study conducted on the various constant parameters associated with it gives an idea of the factors to account for when using MT rose charts to determine maximum wave amplitude estimates.
MT rose charts are then used to study the meteotsunami hazard for Clearwater, FL, and some of the critical scenarios identified. In addition, a new visualization tool, the severe MT rose chart, was developed to summarize the hypothetical AD scenarios that could produce MT with an amplitude of more than 0.3 m. This new tool was then applied to 7 other places or communities along the Gulf of Mexico to study how the coastal morphology and bathymetry of the region relate to MT events. ADs with forward speeds around 14 m/s along broad continental shelves were observed to produce the most severe MTs. At the same time, narrower continental shelves cause the most severe MTs for fast-moving ADs in the range of 24-40 m/s forward speed. These tools have been established on publicly available web pages for hazard mitigation by emergency managers or third parties.
The role of bathymetry in determining the amplitude of meteotsunami events underscores the necessity for comprehensive bathymetric data. Utilizing Autonomous Surface Vehicles (ASVs) can effectively fulfill this requirement. The data collected by these ASVs will serve as an input to the numerical models for meteotsunami, helping create more accurate predictions. There is much development in ASV technologies. Concurrently, hydrofoil surfboards, which experience very little resistance from the water, are increasingly becoming popular for recreation. This project combines these ideas to develop an energy-efficient moving-mass actuated stabilizer single-mast Hydrofoil ASV (MASS-foil ASV). MASS-foil ASV can be utilized in effective bathymetry surveys, among other applications. The first component of the research and development (R&D) was an experimental setup and procedure designed to test the hydrodynamic characteristics of the submerged portion (sub-structure) of the vessel. This experimental study resulted in an understanding of the drag and lift behavior of the hydrofoil substructure, which can be used in the formulation of a model for the dynamics of the vessel and the validation of the CFD model.
The main focus of R&D after this was on developing a model to describe the dynamics of the MASS-foil when it is foiling. The perturbation equations about the cruising speed of the MASS-foil were derived utilizing some empirical models verified using experiments earlier and making suitable assumptions. The equations are then employed to design an optimal control system using a Sampled Data Regulator to stabilize the motions experienced by it. Simulations are performed to analyze and demonstrate the effectiveness of the controls implemented. Several wave forcing scenarios were also studied to understand MASS-foil���s susceptibility to them.
A prototype of the MASS-foil is being fabricated, and the progress so far has been shown
Parent and Youth Perceptions of Social Competence and Friendships for Youth with Attention-Deficit/Hyperactivity Disorder and/or Internalizing Symptoms
No full textIt is known that having ADHD symptoms can cause impairments in psychosocial functioning. Children and adolescents with ADHD often exhibit difficulties in interpersonal relationships with peers (Mrug et al., 2012) and potential social competence deficits (Hoza et al., 2004). More studies are needed to examine the comparison of parent and youth self-reports on social competence and friendships in youth with ADHD and internalizing symptoms (Becker et al., 2012; Becker at al., 2015). Particularly, few studies have examined or compared these reports spanning the developmental periods of childhood to adolescence. This study examined parents��� perceptions and adolescents��� self-reports of internalizing symptoms (i.e., anxiety and depression), as well as youths��� perceived social competence and friendships in a sample of children/adolescents with ADHD comorbid with internalizing symptoms (e.g., ADHD group) and non-ADHD samples (e.g., Typical Development group), at ages 9 and 15. A sample of 2511 participants (ADHD group = 400, Typical Development group = 2111), from two waves of longitudinal data (ages 9 and 15), were collected from the Future of Families and Wellbeing Study (FFCWS). Each child���s parent completed questionnaires on internalizing symptoms and social competence at both waves. Adolescents at age 15 completed questionnaires on perceived friendships and social competence. When youth were 9 years old, parents��� report of their internalizing symptoms was higher in the ADHD group, and parents��� report at their children���s age 15 was consistent with their report at youth age 9, with the ADHD group having higher parent reports of internalizing symptoms in both groups. Parents��� reports of internalizing symptoms differed from adolescent self-reports of internalizing symptoms within the Typical Development and ADHD groups, as parents reported higher levels of internalizing symptoms in their children than adolescents reported within the ADHD group. Parent ratings of their child���s social competence at age 9 was found to be a positive predictor of youths��� self-perceptions of their social competence and for friendships. Particularly, adolescents with ADHD perceived themselves differently than typically developing youth their age: The ADHD group reported lower levels of social competence and friendships
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Get PDFAn Analysis of the Practicality of Hardware Acceleration for Lightweight Block Ciphers in a Field Programmable Gate Array
No full textThe Internet of Things (IoT) is prompting a rapid shift in the way that encryption is performed by resource-constrained devices. Embedded devices are unable to implement the same cipher algorithms that general-purpose computers use. This project aims to examine practical considerations for implementing lightweight block cipher algorithms in a field programmable gate array (FPGA) for the purpose of hardware acceleration of encryption for constrained devices. To do this, four block cipher algorithms were implemented. Three lightweight ciphers from ISO 29192-2 (Present, Clefia, and Lea) and the Advanced Encryption Standard (AES) were selected. In addition, the necessary logic to have them interface with another device such as a microcontroller was implemented. The effectiveness of the serial communication between the FPGA and microcontroller is examined using metrics such as data transmit speed and the maximum feasible clock speed. The performance is analyzed using metrics such as computation time, encryption throughput, power consumption, efficiency, and the number of logic units used