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AbstractFace cups form a vital component of breathing, assisting with devices that aid in artificial breathing for neonates. This study aims to evaluate the flow parameters in the nasal cavity for two different types of face cups. The neonatal nasal cavity model was developed from CT scans using MIMICS 21.0. Two face cups, one hemispherical and the other anatomical shaped cups are developed around the nasal cavity and the airflow is simulated using ANSYS 2021 R2. Results are compared with a nasal-only model. At the nasal valve region, the highest velocity is seen for the nasal-only model which is 16.3% higher than that of the hemispherical face cup and 15.2% superior to the anatomical-shaped face cup. In addition, the decrease in pressure across the nasal-only model is 7.4 and 6.6% below that of the hemispherical cup and anatomical cup masks. The nasal resistance values across the nasal cavity are the lowest for the nasal-only model, 7.7 and 6.7% lower respectively than the hemispherical and anatomical-shaped cups. There were very minor changes in the flow parameters such as velocity, pressure and wall shear stress when comparing the hemispherical and anatomic-shaped masks for the airflow inside the nasal cavity. [ABSTRACT FROM AUTHOR]

3-D E-glass fabric reinforced epoxy composites at 6 mm thickness were fabricated for various orientations of the binder yarn viz. 0°, 30°, 45°, 60° and 90° respectively. Tensile, flexural, interlaminar shear stress tests were conducted to ascertain the influence of binder yarn orientation on the mechanical properties of the composites. The composites with 0° binder yarn orientation showed the best strength followed by 90° whilst the others showed highly depleted traits in comparison. Shear stress induced at the interface of each lamina was seen as the major reason for drop in the strength. A secondary study was carried out to explore the effect of compression factor during fabrication on the mechanical properties of the composites. Laminates with varying thickness namely, 4 mm, 5 mm and 7 mm but, with same number of plies of 3D E-glass fabric at 0° orientation were fabricated. The test results were compared with the results of 6 mm composites from the primary study. The results showed that, compression factor affected the mechanical properties of the composites and had a direct relation with increasing compression factor up to a certain value beyond which a drop in properties was seen. Composites pressed to a thickness of 5 mm showed the best properties. Drop in properties was attributed to close packing of reinforcement and crushing of fibres leading to inefficient stress transfer. Scanning electron microscopy was employed to understand the modes of failure. The major failure modes observed were delamination, matrix cracking and debonding. Based on the results obtained, these composites can be seen as a material system for applications like ballistic armours, structural renovations and automobile components.

Objective: The nasal cavity effectively captures the particles present in inhaled air, thereby preventing harmful and toxic pollutants from reaching the lungs. This filtering ability of the nasal cavity can be effectively utilized for targeted nasal drug delivery applications. This study aims to understand the particle deposition patterns in three age groups: neonate, infant, and adult. Materials and methods: The CT scans are built using MIMICS 21.0, followed by CATIA V6 to generate a patient-specific airway model. Fluid flow is simulated using ANSYS FLUENT 2021 R2. Spherical monodisperse microparticles ranging from 2 to 60 µm and a density of 1100 kg/m3 are simulated at steady-state and sedentary inspiration conditions. Results: The highest nasal valve depositions for the neonate are 25% for 20 µm, for infants, 10% for 50 µm, 15% for adults, and 15% for 15 µm. At mid nasal region, deposition of 15% for 20 µm is observed for infant and 8% for neonate and adult nasal cavities at a particle size of 10 and 20 µm, respectively. The highest particle deposition at the olfactory region is about 2.7% for the adult nasal cavity for 20 µm, and it is <1% for neonate and infant nasal cavities. Discussion and conclusions: The study of preferred nasal depositions during natural sedentary breathing conditions is utilized to determine the size that allows medication particles to be targeted to specific nose regions. [ABSTRACT FROM AUTHOR]

Considering the current growth of design and development activities in micro/mini-Unmanned Aerial Vehicles (UAVs), there is a significant need for thin, durable and lightweight composites for their structural applications. Robust and impact-resistant materials are deemed mandatory concerning the harsh operational conditions where these UAVs are employed. Numerical models for composite materials at various loading conditions can bring up tremendous pace in various design and manufacturing aspects of such competent and tailored engineering materials. Numerical simulations of low velocity flatwise Charpy impact are performed on carbon/aramid hybrid laminates. The modelling is based on representative volume element (RVE) micro-scale property homogenisation in ANSYS Workbench, followed by macroscale impact analysis in ABAQUS/EXPLICIT. The damage propagation was determined using the Hashin failure criteria. The numerically predicted results were validated against the experimental data concerning the energy absorbed and impact strength. The results provided by the modelling are in good correlation with the experimental observations. The numerically obtained force-time data correlated the damage propagation and failure modes observed in the post-impact damage morphology in the laminate during the non-instrumented Charpy test. [ABSTRACT FROM AUTHOR]

Natural fiber-reinforced polyester composites were prepared using bast fibers as the reinforcement which were extracted from Grewia serrulata trees. Chemical treatments such as alkali pretreatment followed by permanganate treatment, acetylation and silane treatment were exclusively applied to modify the fiber surface. Hand lay-up technique with compression molding was adapted for the fabrication of axially oriented fiber reinforced composites. Tensile, flexural and impact strength properties of the specimens prepared were evaluated following the standard procedures. The SEM images of the fractured surfaces shows improvement in compatibility between the chemically treated fibers and the matrix. It was found that the tensile and flexural strengths of chemically treated fiber-reinforced polyester composites have significantly improved when compared to untreated fiber-reinforced polyester specimens. The properties of 1200 hrs water aged specimens were found deteriorated considerably due to diffusion of water into the composite material system. The chemical treatment of fibers prior to fabrication of composites improves the resistance to water absorption tendencies.

PID control is widely used for designing controllers in production plants and automotive and robotic applications. Although it suits linear systems, with minor modifications, it can also be applied to nonlinear plants. As a simple control approach, it can be easily realized conceptually, but there is a large cost involved in the production of the working controller. A digital PID controller based on a fixed point representation of the operands can be considered for approximate realization. The field programmable gate array (FPGA), with its concurrent architecture, is an ideal way of producing programmable, cost‐, power‐, and speed‐optimized controllers with a compromised controller area compared to application‐specific approaches. In this research, the PID controller for quadcopters is initially tested for performance using MATLAB/Simulink based on continuous/analog domain operations. Then, FPGA‐based architecture mapping is performed using HDL Coder, with fixed‐point‐based operands produced using the fixed‐point conversion toolbox. With satisfactory performance obtained with system generator‐based cosimulation of the controller, Vivado IDE is used to implement the controller on a Zynq Ultrascale+ based FPGA device. The realized cost‐efficient controller is analysed for logical resources, computation power and controller frequency and inferred to be optimal with reference to all these indices. By adapting the thrust, which is the control input for the translational motion of the quadcopter, robustness against coupled motion is ensured, with higher simultaneous tracking speeds. [ABSTRACT FROM AUTHOR]

Today, the turbomachinery engineering plays a vital role in the field of air breathing propulsion, most importantly the components like compressor, turbine and its possible numerical strategies to improve the overall efficiency especially in the transonic flow conditions. The main objective of this paper is to address the numerical solution for most uncertain problem like unsteady and non-uniform flow across the axial-flow compressor. The axial-flow compressor distorted flow problem is modeled and analyzed by means of a systematic three-dimensional numerical approach. Particularly, the rotor inflow instability implications of an axial compressor stage are carried out. Geometry is created using ROTOR-37 coordinates for numerical analysis and the results are validated in contradiction of experimental data available from literature, by imposing various combinations of Mach numbers from 0.8 to 1.2 and the engine mass flow rate of incoming air. The results highlighted that the rotor blade main distortion effect was noticed at near the tip region and as well as the hub corners of the blade. Numerical simulations also revealed that due to the distortion influence, the stream flow separation on pressure side of the blade is more. Moreover, these calculated figures have more significance for better aero-mechanical features of axial-flow compressor.

The novel coronavirus responsible for COVID-19 has spread to several countries within a considerably short period. The virus gets deposited in the human nasal cavity and moves to the lungs that might be fatal. As per safety guidelines by theWorld Health Organization (WHO), social distancing has emerged as one of the major factors to avoid the spread of infection. However, different guidelines are being followed across the countries with regards to what should be the safe distance. Thus, the current work is an attempt to understand the virus deposition pattern in the realistic human nasal cavity and also to find the impact of distance that could be termed as a safety measure. This study is performed usingComputationalFluid Dynamics as a solution tool to investigate the impact of COVID-19 deposition (i) On a realistic 3D human upper airway model and (ii) 2D social distancing protocol for a distance of 0.6, 1.2, 1.8, and 2.4 m. The results revealed that the regional deposition flux within the nasal cavity was predominantly observed in the external nasal cavity and nasopharyngeal section. Frequent flushing of these regions with saltwater substitutes can limit contamination in healthy individuals. The safe distancing limit estimated with 1 m/s airflow was about 1.8 m. The extensive deposition was observed for distances less than 1.8 m in this study, emphasizing the fact that social distancing advisories are not useful and do not take into account the external dynamics associated with airflow. [ABSTRACT FROM AUTHOR]