New Approaches in Engineering Research Vol. 16

Burr and film are common when punching cable ducts made of polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS). Additional deburring processes are required as a result, which is reflected in the product price. The punching process is investigated in the following study using Design of Experiments to emphasize the relationship between the input variables (factors) and the output variables (quality characteristics). The punching process was examined, and the key factors were identified and rated using a Failure Mode and Effects Analysis (FMEA). The Pareto approach was then used to choose the rated factors. The Software Modde was used to define factor levels and a D-optimal screening test plan. Using illustrated evaluation catalogues, the resulting quality characteristics were categorically appraised. The quality-characteristic mathematical models were then optimized and evaluated. The findings show that clearance is the most important factor in all five quality criteria studied. It is interesting to note that for some quality characteristics a reduction of the clearance would be positive, whereas for some a reduction would be positive. Between these two boundaries, it is considered that an ideal clearance size exists. In addition to the clearance, a holding-down of the material, in the close vicinity of the punch-out, during the punching of PC/ABS is essential for good results.

One of the process steps in the production of cable ducts is punching the side recesses. Polyvinyl chloride (PVC) has already been successfully processed using this method. Punching flame-retardant polycarbonate/acrylonitrile butadiene styrene (PC/ABS) cable ducts, on the other hand, is challenging. There is an increase in burr and film formation. Both reduce the quality of the end product and thus make an additional deburring process necessary. Using high-speed recordings and a transparent tool, this research attempts to visualize and adjust burr and film creation. This identifies the first burr and film formation. Then, if necessary, optimization steps can be defined. Because the returning punch effects the burr and film, analyzing the existing burr and film is false. In order to formulate optimization procedures, the existing punching processes for PVC and PC/ABS were compared. As a result, snapshots from the high-speed recordings were assigned to the process steps in question. This revealed the commencement of film development and its reasons, as well as the fact that PVC and PC/ABS shatter in various ways.

In this chapter, study of  new Stilling Basin Model have been carried out for non-circular pipe outlet keeping the outlet at zero depth from the basin of floor.  Evolution was carried out after testing of twenty four models using different appurtenances like impact wall, intermediate sill and end sill. Testing of Stilling Basin Model have been performed for non-circular pipe outlet with Froude number 3.85. All models were experimented using same bed materials and tail water depth was kept constant as normal depth and test duration was kept constant as forty five minutes for all models. After test run of forty minutes duration Scour parameters were measured and performance of model were measured by computing Scouring index. The Scour indexes after the end sill were estimated for each test run. After experimentation, it was found that new developed stilling basin model with appurtenances of rectangular intermediate sill of cross section 0.5 d width and 1d height, impact wall of dimensions 1 d x 2.2 d and a triangular end sill of cross section 1 d width and 1 d height at basin length of 6.4 d performed better as compared to other tested models with zero depth of pipe outlet from basin floor. Performance of new developed Stilling Basin Model is 49% efficient as compared to USBR VI stilling basin model and the stilling basin length is also reduced by 23%. Thus this model is emerged as the best Stilling Basin Model among all other tested models as it is efficient and economical as compared to USBR VI Stilling Basin Model at zero depth of pipe outlet.

This paper reports on the design and simulation of source-field-plated Ga₂O₃ power MOSFETs, investigating breakdown voltage, interface oxide charges and its relationship with the threshold voltage. For the device structure modeled a threshold voltage of -50 V is extracted.  This value is comparable to the published experimental results with a similar device structure and physical parameters where an interface oxide charge density of 5 x10¹³ /cm² is assumed in simulation.   Simulation results indicate a breakdown voltage of 600 V and Ron resistance of 40 W-mm for Ga₂O₃ n-MOSFETs when a channel doping density of 1.5 x 10¹⁶ cm^-3 is used. These results are in agreements with measured value of electric field breakdown and Ron resistance reported by others.

Adequately identifying and managing hazards at the workplace can be a tedious task which extends into the realm of uncertainty, probability and prediction models in order to fully comprehend the nature of the hazard. As such, organizations cannot be blamed for knowledge gaps in the training of personnel they contract to ensure a safe and healthy work environment, especially where there are latent hazards.

Electromagnetic wave propagation at frequencies in the SAR (specific absorption rate) region is a special concern to authorities involved in setting RF (radiofrequency) and microwave exposure guidelines. Despite that there is no conclusive evidence to suggest that non-ionizing electromagnetic radiation causes adverse health effects other than thermal, no effort should be spared to ensure that workers and the public at large are adequately protected from unnecessary exposure to radiation. Standards however set exposure limits for free space, plane wave propagation but fall short in compiling information on intensities of these waves after they undergo reflection and diffraction from wall surfaces.

This review visits a theoretical model for potential energy build-up due to RF propagation in confined spaces that are of waveguide design but with larger dimensions.  Such confined spaces include silos, tanks, pipes, air-condition ducts, tunnels, and operator rooms on board vessels. In these confined spaces rf waves reflect off of the walls and combine constructively or destructively with incident waves producing reinforcement or cancellation respectively.  Where there is reinforcement, the intensity of the wave for a particular distance in accordance with the standard, may exceed the exposure limit for this distance from the source thereby exposing the worker to larger intensities than the accepted limit and presenting a potential health and safety threat. In this way, waveguide theory and physics principles have been proposed as the building blocks for the model construction.

Flat plates weakened by presence of sharp V-notches subject to axial loads are analyzed by various researchers. Attempts towards mitigation of stress concentration factor due to V-notches are limited. In the present work, mitigation of the stress distribution due to  notch under in-plane static loading in rectangular isotropic plates using area reduction method. The variations of stress concentration factor (SCF) for different b/A ratios, depth of V-notch to plate width is established, for subtended angle, 2\(\alpha\), of V notch 60^o, 90^o, 120^o, and 150^o. Mitigation in stress concentration factor (SCF) around main notch has been carried out by introducing auxiliary semi circular notches around V-notch. Effect of various geometric parameters on the stress mitigation is also studied. The optimum size and position of auxiliary semicircular notches has been obtained. The work has been carried out using finite element analysis and two dimensional photo elasticity method. The results are shown in graphical forms and discussed. The mitigation thus obtained in Stress Concentration Factor due to introduction of semicircular notches in the vicinity is encouraging.

The controller implementation for the generation of PWM signals is critical to obtaining the desired response of the sensor less Vector controlled Induction Motor (SVC-IM) by the experimental setup. With the rapid growth of the electronic industry, such as high speed digital signal processors (DSPs) with microcontrollers available these days, it is possible. Previously, DSP technologies were used to implement the various SVC-IM schemes, namely KF, PI, GA, and PSO. It causes problems related to the time delay and execution of the PWM signals, etc., as a results system becomes complex. As a result, a new approach is implemented to address the issue of execution time, namely Field Programmable Gate Array (FPGA) processors, which are currently being proposed in the market.  Furthermore, the programming is done in VHDL, which is a very high-speed hardware descriptive language.

Determining a seizure is essential in order to support the diagnosis and treatment of an epileptic patient. The objective of this work is to automatically detect the epileptic seizures in a patient from EEG signal. As compared to different biological signals like PET, MEG, MRI and fMRI, the EEG signal is found to be more advantageous. The recorded EEG signal was first preprocessed. Features of the EEG signal were then obtained and finally it was classified into seizure or normal on the basis of the calculated features. The results were compared among the features like Mean, PSE (Power Spectral Entropy), variance and energy and the best performing features were selected. Weighted combinations of these features were obtained in order to confirm a robust feature vector. In this paper, we propose a weighted combination of variance and energies (in two particular frequency bands), resulting in a composite feature. We set a threshold for this composite feature, on the basis of which, a given EEG signal can be classified into a normal or a seizure sequence. The proposed composition of features gives up to 96.5% accuracy.

Human computer interaction is a fast growing area of research where in the physiological signals are used to identify human emotion states. Now a day, gaming Disorder has become a major source of concern in recent years and has therefore created immense interest among researchers for further study. In this paper, work is carried out to detect the emotional behavior of the subject who involve in online games regularly using Electroencephalography (EEG). EEG is a low cost, high temporal resolution popular tool which can be used for studying addictive behaviors. As a result, EEG will serve as a reliable indicator of the subject's emotional state. In the present work, the training model is for emotion states is done using SEED-IV data base and testing of gamming addiction behavior is done for acquired signals. The spectrogram features are fed to the VGG pre-trained model. The trained model performance of prediction accuracy of 89.54% and testing accuracy of 78.63% on SEED-IV database is obtained. The acquired signals are tested on the trained model and an accuracy of 75% is obtained.

Banana is one of the top produced crops in the Philippines, and among its cultivars is the Musa balbasiana, commonly known as Saba. Due to its high moisture content, Saba is perishable and one of the methods to increase its shelf-life is drying. Because of its shelf life, it must be consumed a few days after harvest. The shelf life of Saba can be extended up to six months when dried to 12% moisture content. The research focuses on the effect of banana maturity and choses a mathematical model which will best fit its drying kinetics. The banana samples, the unripe and ripe Saba, were bone-dried without pre-treatment using a hot-air tray drier. To produce repeatable data, three trials were done for temperatures 40^oC, 50^oC and 60^oC. Among the three mathematical models used in the study, the treated data for both unripe and ripe Saba best fit the Laplace Transform Model. Using Lagrange interpolation, the time per trial was computed; unripe Saba dried at 50^oC achieved the ideal moisture content in an average time of 87.5574 minutes for the three trials while that of ripe Saba dried at 40^oC achieved the same moisture content in an average time of 88.8619 minutes for the three trials. With the increase in temperature, the discoloration decreased indicating an enzymatic character of browning. The difference in the moisture that can be removed from Saba has a greater factor as compared to the temperature in determining the drying time.