COVID-19 DISSEMINATION ASSESSMENT THROUGH NATURAL VENTILATION IN HOSPITAL PATIENT ROOM BY CFD ANALYSIS

This paper studies the effect of natural ventilation on the spread of the COVID-19 virus from a patient room to an adjacent room with the help of airflow. The importance of this study is since COVID-19 virus contamination can easily transfer with the airflow from one room to the next room or adjacent corridor. This paper aims to determine the effect of natural ventilation on the contamination of the spaces next to the COVID-19 patients’ room.For this evaluation, we have used mechanical modelling and CFD simulation to evaluate the effect of natural ventilation on the transmission of COVID-19 with the airflow from a contaminated space to a clean space. During this study, we have calibrated the CFD model using one actual case, that was studied in a wind tunnel, and verified the modified model with the actual existing case. The simulated CFD model showed a reasonable accuracy for the prediction of ventilation in indoor spaces.Results showing the room geometries with air inlet/outlet that positioned at either bottom or top of the room will result in less COVID contamination dissemination through natural ventilation. In addition, in case of having the inlet/outlet in middle and positioning face to face and as well in the case of having max natural air velocity, the maximum contamination will exhaust from the space.

Magnetic Resonance Compatible Knee Extension Ergometer

A magnetic resonance (MR) compatible ergometer has been developed to study contracting lower limb muscles during acquisition of MR spectroscopy data, a technique to noninvasively measure metabolic energy in muscle tissue. Current active and passive MR-compatible ergometer designs lack torque or velocity control to allow precise mechanical measurements during isotonic and isokinetic contractions; incorporating load and velocity controllers while maintaining MR-compatibility is the main challenge. Presented in this paper is the design and evaluation of an MR-compatible ergometer designed to control knee torque or velocity up to 420 N·m and 270 deg/s and is able to operate in a 3 Tesla magnetic field. The ergometer comprising of a passive component with no electronics or ferrous materials is located inside the bore of the scanner. The active component with the electronics and actuator located outside of the magnetic field in an adjacent room. The active components connect to the passive components via a cable that passes through the waveguide, a hole in the wall of the scanner room. System evaluations were performed and human subject evaluations were performed that measured the mechanical performance and show the mean percent errors below 9% in isotonic and 2% in isokinetic conditions.

FIELD MEASUREMENT OF AIRBORNE SOUND INSULATION BETWEEN ROOMS

Airborne sound can be a nuisance and a constant expose to the sound can in- troduced health problems to the people in the area especially areas where quiet environ- ment is a necessity. The objective of this measurement is to demonstrate the field mea- surement of the airborne sound insulation properties of interior walls. The measurement was done for determining the sound insulation properties of a partition between two rooms. This measurement will also determine the parameters and source of the prob- lems which are contributing to the airborne sound from the adjacent room. The results are that the volume of the room and the construction of the room (pipe construction and ceiling, etc.) have large effects to the sound transmitted between the rooms.

Determination of a Methodology to Derive Correlations Between Window Opening Mass Flow Rate and Wind Conditions Based on CFD Results

This paper presents a methodology for the development of an empirical equation which can provide the air mass flow rate imposed by single-sided wind-driven ventilation of a room, as a function of external wind speed and direction, using the results from Computational Fluid Dynamics (CFD) simulations. The proposed methodology is useful for a wide spectrum of applications, in which no access to experimental data or conduction of several CFD runs is possible, deriving a simple expression of natural ventilation rate, which can be further used for energy analysis of complicated building geometries in 0-D models or in object-oriented software codes. The developed computational model simulates a building, which belongs to Rheinisch-Westfälische Technische Hochschule (RWTH, Aachen University, Aachen, Germany) and its surrounding environment. A tilted window represents the opening that allows the ventilation of the adjacent room with fresh air. The derived data from the CFD simulations for the air mass flow were fitted with a Gaussian function in order to achieve the development of an empirical equation. The numerical simulations have been conducted using the Ansys Fluent v15.0® software package. In this work, the k-w Shear Stress Transport (SST) model was implemented for the simulation of turbulence, while the Boussinesq approximation was used for the simulation of the buoyancy forces. The coefficient of determination R2 of the curve is in the range of 0.84–0.95, depending on the wind speed. This function can provide the mass flow rate through the open window of the investigated building and subsequently the ventilation rate of the adjacent room in air speed range from 2.5 m/s to 16 m/s without the necessity of further numerical simulations.

Thermal functioning of a transparent barrier equipped with a system of external thermal insulation shields

The article presents the results of tests of the thermal operation of a transparent barrier, which is equipped with an external thermal insulation roller blind. The tests were carried out under real climatic conditions. The barrier in question was mounted on the south façade in two external test chambers. The aim of the research was to determine whether and to what extent the external thermal insulation roller blind influences the flow of heat through the transparent barrier. The second goal was to propose a way of programming the position of the blind so that it would be beneficial in both limiting of overheating in the adjacent room during the high summer sunshine and minimizing the need to reheat the room in the case of high clouds and low temperatures in the outside air. During the tests, the following values were measured: the intensity of solar radiation, temperature (outside air, indoor air and the internal surface of the barrier), as well as the heat flux density on the internal surface of the barrier. The test results indicate that the use of an external thermal insulation roller blind has a significant impact on the thermal operation of the transparent barrier and thermal comfort in the room adjacent to the barrier. The method of programming of the position of the blind should take into account both the temperature of the outside air and the value of the intensity of solar radiation, as well as the temperature of the air in the room adjacent to the barrier, and the direction and values of the heat flux passing through this barrier.

Criteria and Characteristics of Elevator Noise in Apartments

Elevator noise in apartments can make annoying sounds depending on locations of elevators and the sensitivity of the residents. Some nations have their own criteria regarding noise from elevators, however, South Korea has no such criteria, which makes it difficult to handle the damage due to noise from elevators. Thus, the present study investigated noise criteria in elevators in other nations and identified the noise characteristics during elevator operation to provide foundational data at the time of setup on noise criteria forelevators. The noise criteria in other nations recommend the maximum noise level to be below NC-20–30 and 25–30 dB(A). The noise measurement in elevators showed that the maximum noise level at the adjacent room was NC-29, 31.4 dB(A) in A Apartment, and NC-26~29, 30.8–32.7 dB(A) in B Apartment.