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1.
ASHRAE Transactions ; 128:340-347, 2022.
Article in English | ProQuest Central | ID: covidwho-1970581

ABSTRACT

The wavelength band of200-280 nm of UV-C radiation generated by the Ultraviolet Germicidal Irradiation (UVGI) system can destroy the reproduction ability of microorganisms. Severalfactors related to UVfixtures, HVAC layout, and the resulting airflow flow patterns can affect the performance of upper-room UVGI applications. With the help of Computational Fluid Dynamics (CFD) analyses, this study systematically evaluates the impact of UV-C intensities on the effectiveness of an upper room UVGI system. It shows that the addition of even a small amount of UV-C energy in the upper region of space can significantly reduce the probability of infection as predicted by the Wells-Riley model. Increasing the UV-C output shows a further reduction in the infection probability, although with a diminishing impact. A further investigation is necessary to evaluate the effect of airflow patterns on the performance of UVGI systems. These studies demonstrate that CFD analyses can help optimize the performance of UVGI systems to minimize the probability of infection in indoor spaces.

2.
Drones ; 6(4):97, 2022.
Article in English | ProQuest Central | ID: covidwho-1809768

ABSTRACT

This paper presents the design of a small size Unmanned Aerial Vehicle (UAV) using the 3DEXPERIENCE software. The process of designing the frame parts involves many methods to ensure the parts can meet the requirements while conforming to safety and industry standards. The design steps start with the selection of materials that can be used for the drone, which are polylactic acid (PLA), acrylonitrile styrene acrylate (ASA), and acrylonitrile butadiene styrene (ABS). The drone frame consists of four main parts, which are the center top cover (50 g), the side top cover (10 g), the middle cover (30 g), and the drone’s arm (80 g). A simulation was carried out to determine the stress, displacement, and weight of the drone’s parts. Additionally, a trade-off study was conducted to finalize the shapes of the parts and the various inputs based on their priorities. The outcome of this new design can be represented in design concepts, which involve the use of the snap hook function to assemble two body parts together, namely the middle cover and the center top cover, without the need of an additional fastener.

3.
Remote Sensing ; 14(7):1540, 2022.
Article in English | ProQuest Central | ID: covidwho-1785891

ABSTRACT

This paper presents a heterogeneous configuration of the multirotor unmanned aerial system (UAS) that features the combined characteristics of the helicopter and quadrotor in a single multirotor design, featuring the endurance and energy efficiency similar to a helicopter, while keeping the mechanical simplicity, control, and manoeuvrability of the standard quadrotor. Power needed for a rotorcraft to hover has the inverse relation with the rotor disc. Therefore, multiple small rotors of the quadrotor are energetically outperformed by a large rotor of the helicopter, for a similar size. Designing the stable control system for such a dynamically complex multirotor configuration remains the main challenge as the studies previously carried out on these designs have successfully demonstrated energy efficiency but at the cost of degraded attitude control. Advancements in the energetics of the multirotor results in enhanced endurance and range that could be highly effective in remote operation applications. However, a stable control system is required for accurate positioning. In this paper, a cascaded PID control approach is proposed to provide the control solution for this heterogeneous multirotor. Automatic tuning is proposed to design the PID controller for each loop of the cascade structure. A relay feedback experiment is conducted in a controlled environment, followed by identification of the open-loop frequency response and estimation of dynamics. Subsequently, PID controllers are tuned through approximated models with the help of tuning rules. A custom-designed flight controller is used to experimentally implement the proposed control structure. Presented experimental results demonstrate the efficacy of the proposed control strategy for heterogeneous multirotor UAS.

4.
Buildings ; 12(3):355, 2022.
Article in English | ProQuest Central | ID: covidwho-1760396

ABSTRACT

The transportation and surface deposition of aerosols from sneezing in a small indoor farmers’ market are studied numerically. The effects of numbers and locations of the entrances and exits of the market are discussed under the condition of natural convection. The results indicate that aerosols leave the indoor environment more quickly when two doors are designed face to face on the walls perpendicular to the natural wind direction compared to other natural ventilation strategies. The concentrations of aerosols accumulated on the surfaces of the stalls and human bodies inside the market are also lower. In this case, the risk of contacting the virus is relatively low among susceptible individuals in the indoor farmers’ markets. Moreover, opening more doors on the walls parallel to the natural wind direction is not beneficial for the fast exhaust of aerosols.

5.
Fluids ; 7(2):62, 2022.
Article in English | ProQuest Central | ID: covidwho-1715220

ABSTRACT

In this review, we summarize existing trends of flow control used to improve the aerodynamic efficiency of wings. We first discuss active methods to control turbulence, starting with flat-plate geometries and building towards the more complicated flow around wings. Then, we discuss active approaches to control separation, a crucial aspect towards achieving a high aerodynamic efficiency. Furthermore, we highlight methods relying on turbulence simulation, and discuss various levels of modeling. Finally, we thoroughly revise data-driven methods and their application to flow control, and focus on deep reinforcement learning (DRL). We conclude that this methodology has the potential to discover novel control strategies in complex turbulent flows of aerodynamic relevance.

6.
Applied Sciences ; 12(4):2198, 2022.
Article in English | ProQuest Central | ID: covidwho-1706204

ABSTRACT

Featured ApplicationMicrofluidics device for rapid antibiotics susceptibility screening for bacterial strains in laboratory environment.In recent years, excessive utilization of antibiotics has led to the emergence of antibiotic microbial resistance on a planetary scale. This recent phenomenon represents a serious threat to public health, as well as an enormous burden for healthcare systems’ budgets worldwide. Novel, rapid and cheap methods for antibiotic susceptibility screening are urgently needed for this obstacle to be overcome. In this paper, we present a microfluidic device for on-chip antibiotic resistance testing, which allows for antibiotic microbial resistance detection within 6 hours. The design, fabrication and experimental utilization of the device are thoroughly described and analyzed, as well as possibilities for future automation of the whole process. The accessibility of such a device for all people, regardless of economic status, was of utmost importance for us during the development of the project.

7.
Mathematical Problems in Engineering ; 2022, 2022.
Article in English | ProQuest Central | ID: covidwho-1701014

ABSTRACT

This work presents the splitting dynamics of low-viscous fingers inside the single bifurcating channel through the surface wettability of daughter branches. The propagation of low-viscous fingers inside branching microchannels have importance in many applications, such as microfluidics, biofluid mechanics (pulmonary airway reopening), and biochemical testing. Several numerical simulations are performed where a water finger propagates inside the silicon oil-filled bifurcating channel, and at the bifurcating tip, it splits into two fingers and these fingers propagate into the separate daughter branches. It is noticed that the behaviour of finger splitting at the bifurcating tip depends upon numerous parameters such as surface wettability, capillary number, viscosity ratio, and surface tension. This study aims to trigger the behaviour of finger splitting through the surface wettability of daughter branches θ1,θ2. Therefore, a series of numerical simulations are performed by considering four different surface wettability configurations of daughter branches, i.e., θ1,θ2∈78°,78°;78°,118°;78°,150°;150°,150°. According to the results obtained from numerical simulations, finger splitting may be categorized into three types based on splitting ratio λ, i.e., symmetrical splitting, nonsymmetrical splitting, and reversal (no) splitting. It is noticed that the surface wettability of both daughter branches is either hydrophilic 78°,78° or superhydrophobic 150°,150°, providing symmetrical splitting. The surface wettability of one of the daughter branches is hydrophilic and another is hydrophobic 78°,118°, providing nonsymmetrical splitting. The surface wettability of one of the daughter branches is hydrophilic and another is superhydrophobic 78°,150°, providing reversal splitting. The findings of this investigation may be incorporated in the fields of biochemical testing and occulted pulmonary airways reopening as well as respiratory diseases such as COVID-19.

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