Magneto-Rotational Augmentation of Bioconvective Transport in Plasma-Nanofluid Flowing through a Penetrable Spinning DiscRead the full article
Journal of Engineering publishes research in several areas of engineering, including chemical engineering, civil engineering, computer engineering, electrical engineering, industrial engineering and mechanical engineering.
Chief Editor, Professor Wang, is the Vice Deputy Dean of the School of Aerospace Engineering at Tsinghua University.
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Effect of SiC Addition on Microhardness and Relative Density during Selective Laser Melting of 316L Stainless Steel
The utilization of 316L stainless steel has been very common in marine, automotive, architectural, and biomedical applications due to its adequate corrosion resistance to cracks after the completion of welding process. However, there has been ongoing attempts to investigate the potential enhancement in the strength and durability of 316L stainless steel by reinforcing it with silicon carbide (SiC). The present work adopts the selective laser melting (SLM) technique to fabricate SiC-reinforced 316L steel to boost its microhardness and strength properties. The methodology involved the addition of 1% wt. silicon carbide with particle sizes <40 μm to reinforce the stainless steel matrix. An SLM metal printing machine equipped with a continuous wave of 300 W fiber laser is employed to form the specimens. To measure the properties of the final product, EDX, XRD, FESEM, and universal tensile test machines have been used. The maximum value of 296 HV was obtained for a 1% volume of SiC compared to the 285 HV microhardness of pure stainless steel 316L. FESEM examination showed that the SiC microparticles were dissolved completely and they were randomly distributed in the melting basin. The samples were dissolved entirely, and the best porosity was obtained at 0.4% with influential parameters of 200 W laser power, 70 µm hatching distance, 30 µm layer thickness, and 700 mm/s velocities. The results also revealed that the microhardness at these parameters is the best compared to the samples produced with different values. The volumetric energy density was also considered. The findings can be informative to the researchers and manufacturers interested in 316L steel industry.
Experimental Determination of the Effect of Time of Exposure to Heat on Erosion Development in Different Soil Types
Tropical forests are increasingly exposed to devastating bushfires, leading to increased erosion. This work involves the study of the effect of exposure to heat on erosion development. Four different soil samples from the study area were used for the study. In this study, the postfire impacts of a laboratory fire representing a bushfire and a subsequent rainfall simulation experiment representing postfire rainfall were compared to evaluate the short-term impact of fire on heated bare soil. Laboratory observations show that bushfire or wildfire affects the erodibility of different types of soil. When the soil under consideration contains a meaningful amount of clay, initial exposure to heat tends to cement the soil sample, because clay minerals harden on exposure to bush burning. However, it is generally observed that at 6 hours of exposure to burning, the cementation is adversely affected, leading to increased soil loss.
Prediction of the Radiative Properties of Triangular-Grating Surfaces from Electromagnetic Theory
In this paper, we present a study of the influence of roughness on the bidirectional reflectivity and on the emissivity of surfaces using Maxwell’s electromagnetic theory. In this framework, we solve the Helmholtz equations by using the surface integral method. We first proceed to a general description of this method, allowing to solve the propagation equations of the electromagnetic field. We then express the diffused directional flux using the surface field and its normal derivative (source terms), in the case of an incident plane wave in “p” polarization or in “s” polarization. This finally allows us to arrive at the desired radiative properties. We have developed two numerical calculation codes whose use we limit to cases of surfaces presenting cavities in the shape of a symmetrical or asymmetrical “V”. Particular interest was given to the influence of the geometric parameters of these surfaces on the bidirectional reflection function and on the emissivity of these surfaces. Finally, we present some very conclusive results.
Experimental Study of Hollow RC Beams Strengthened by Steel Fiber under Pure Torsion
This paper examines the effectiveness of pure torsional loads on hollow reinforced concrete high-strengthened beams. Engineers need to know how much twist a structural member generates when exposed to torsional loads to design it properly. This is done through an experimental investigation of the torsional behavior of reinforced concrete (RC) beams using twelve hollow rectangular beams with varying parameters, such as the spacing of the stirrups, the influence of the steel fiber fraction, and the main reinforcement amount. Four values of fiber volume fractions (0, 0.5%, 0.75%, and 1%), three spacings of transverse reinforcements (60,100, and 150 mm), and various longitudinal reinforcements (8Ф12 mm, 6Ф12 mm, and 4Ф12 mm) have been used. The tested beams had the same length (1000 mm), cross-sections, concrete mixture, and quality control. In the hollow beams, the interior dimensions were 180 mm × 180 mm, while the exterior dimensions were 300 mm × 300 mm. Torsional loads were applied to all the beams using custom-built test equipment. This study highlighted that the structural characteristics of hollow RC beams could be improved by increasing the fiber volume, lowering the stirrup spacing, and increasing the longitudinal reinforcement. Torsion moments rose by 132% when the fractional volume of fiber was increased from 0% to 1%, while they rose by 71.27% when the longitudinal reinforcement was increased from 4 to 8 bars for beams with fractional volumes of fiber of 0.5 percent and the same transverse reinforcement ratios.
Applications of Artificial Intelligence Enhanced Drones in Distress Pavement, Pothole Detection, and Healthcare Monitoring with Service Delivery
Artificial Intelligence (AI) has fascinated the present study assigned to multiple areas such as distress detection on the pavement, pothole detection, and healthcare. The distress detection on pavement and roads and delivering healthcare and medical services need to be monitored through state-of-the-art technology, i.e., drone technology. Improvement in construction sites and healthcare delivery are of serious concern. Nowadays, computer vision techniques are commonly used in this area utilizing images and videos of construction sites. Due to confined data, researchers are using Unmanned Aerial Vehicles (UAVs) or Drone to get maximum information through 360° monitoring. This review article presents the useful monitoring techniques using AI-enabled drones for scholars around the world. In this comprehensive review, initially, the image acquisition equipment along with the perks and limitations has been presented. Second, the main constraints related to different computer vision techniques are highlighted for detecting distress in the pavement. Then, the possible research solution to some of the distress issues such that detection of pavement texture, cracks or potholes, joint faulting, temperature segregation, and rutting issues are predicted. Finally, the application of AI-enhanced drones in the healthcare field is elucidated which showed their significance. Moreover, in this research, the comparative image analysis of pavement and path hole detection was presented for the collection of detailed information and accurate detection. In the future, the work can also be enhanced to monitor the live pavement distress detection, especially for busy roads and highways. Moreover, an analysis to determine and reduce the costs in the healthcare sectors and organizations is required for future work.
Modeling and Nonlinear Control of a Quadcopter for Stabilization and Trajectory Tracking
This paper presents an adequate mathematical representation of a quadcopter’s system dynamics and effective control techniques. A quadcopter is an unmanned aerial vehicle (UAV) that is able to do vertical take-off and landing. This study presents a nonlinear quadcopter system’s mathematical modeling and control for stabilization and trajectory tracking. The mathematical model of the system dynamics of the quadcopter is derived using Newton and Euler equations with proper references to the appropriate frame or coordinate system. A PD control algorithm is developed for the nonlinear system for stabilization. Another nonlinear control technique called full state feedback linearization (FBL) using nonlinear dynamic inversion (NDI) is developed and implemented on the quadcopter system. However, there is a problem with the normal approach of the complete derivation of the full state FBL system using NDI as gathered from the literature review. In such an approach, the PD controller that was used for attitude stabilization was able to stabilize the angles to zero states, but the position variables cannot be stabilized because the state variables are not observable. Thus, a new approach where the position variables are mapped to the angle variables which are controllable so as to drive all states to zero stability was proposed in this study. The aim of the study was achieved but the downside is that it takes a longer time to achieve this stability so it is not efficient and should only be considered when absolute zero stability is the aim without considering time efficiency. The study further investigates the problem of nonlinear quadcopter system’s mathematical modelling and control for stabilization and trajectory tracking using the feedback linearization (FBL) technique combined with the PD controller. The proposed control algorithms are implemented on the quadcopter model using MATLAB and analyzed in terms of system stabilization and trajectory tracking. The PD controller produces satisfactory results for system stabilization, but the FBL system combined with the PD controller performs better for trajectory tracking of the quadcopter system.