bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy Absorption Mechanisms and Crash Analysis of Helicopter Seats
Authors: Özturk Gülce , Kayran Altan
Published: January 2019

In this paper, a crushable absorber system is designed to analyze the dynamic behavior and performance of a helicopter seat. The mechanism of the absorption system makes use of the crash energy to plastically deform the aluminum material of the seat legs. Seat structure is composed of a bucket, two legs and two sliding parts on each leg. Seat legs are made of aluminum and and the sliding parts of the seat are steel. During the impact event, the heavier sliding parts move down and crash the aluminum material for the purpose of deforming the aluminum material under the sliding parts and reduce the crash energy. The designed helicopter seat is analyzed using the explicit finite element method to evaluate how the seat energy absorbing mechanism works. Dynamic simulations are performed in ABAQUS by crashing the seat to a fixed rigid wall. To simulate the plastic deformation, true stress-strain curve of the aluminum material of the seat leg has been used. Time response results are filtered to calculate the meaningful g loads which incur damage to the occupants. Analyses are performed with and without the energy absorption mechanism in order to see the effectiveness of the energy absorption mechanism on the human survivability by comparing the g loads on the seat bucket with the acceptable loads specified by EASA. This study is a preliminary study intended to check the effectiveness of the damping mechanism based on the plastic deformation of the aluminum legs of the seat in the event of a crash.
Brain-Computer Interface Application in Robotic Gripper Control
Authors: Landavazo Briana , Nandikolla Vidya K.
Published: January 2019

In robotics research, the electroencephalograph (EEG) based brain-computer interface (BCI) as a control input has been used in designing prosthesis, wheelchairs and virtual navigation. The paper presents the research work on BCI development that communicates between an operator and a robotic gripping device. The control of a BCI robotic hand is broken down into two main subsystems. The first subsystem acquires a signal from the brain through the Emotiv EPOC EEG headset, extracts features and translates them into an input to the control system. The second subsystem incorporates kinematics and feedback from sensors, to control the multiple degrees of freedom used in the gripping device depending on the action specified by the higher-level BCI control. The BCI is trained to filter and extract features relating to the different hand motions from the data sets. Machine learning is used in conjunction with data filtering, feature extraction, and feature classification techniques to create a more accurate and personalized BCI hand control system. The system analyzes the EEG data, compares with the EEG data patterns from previous attempts. The test results demonstrate the movement functions of the gripper using the BCI, and the success rate for each function are presented in this paper.
Steering Strategy for a Multi-Axle Wheeled Vehicles
Authors: Ahmed Waqar , Azim Raja Amer , Fatima Sana
Published: January 2019

This paper presents a mathematical model for multi-axle steering vehicles operating on level ground. For transporting heavy loads vehicles with multiple axles are required. Apart from added complexity steering of multiple axle for turning is a big challenge. Due to type of load being carried a single unit vehicle is sometimes preferred. The mathematical model of a six axle vehicle with 4-axle steering system is developed. Simulations at various track radii, vehicle speeds and steering ratios (ratio between the first, second, fifth and sixth steering axle) are performed. Axle steering angles and wheel slip angles are evaluated. The steering ratio requirements vary with vehicle speed and turn radius. A configuration is selected for better performance for a wider range.

The resulting steering ratios show good vehicle maneuverability, stability and steering efficiency.
Numerical Study of High Temperature Thermochemical Energy Storage Using Co3O4/CoO
Authors: Vahedi Nasser , Ranjha Qasim A. , Oztekin Alparslan
Published: January 2019

Large-scale solar power generation becomes feasible using concentrated solar power plants, as the received heat is collected at high temperatures compatible with power cycle operations. The main drawback of solar power generation is the intermittent nature of available solar irradiation, which results in a mismatch between collected heat and electrical demand. Thermal energy storage (TES) systems are the options to resolve this problem by storing excess heat during high solar irradiance and releasing at off-sun conditions. Thermochemical energy storage (TCES) systems have the potential to store the solar energy at high temperatures suitable for CSP plants’ operations because of the higher energy density of the TCES materials than those used for sensible and latent heat storage options. In TCES, the heat is stored in the form of thermo-chemical energy using an endothermic reaction and is released by carrying out the reverse exothermic reaction. TCES using cobalt oxide redox (reduction/oxidation) reaction is selected for this study because of its unique features suitable for high temperature thermal energy storage. A reactor with the cylindrical fixed bed is considered, in which air flows through the bed during charging and discharging modes. Air is used as heat transfer fluid (HTF) and as the reactant gas supplying oxygen. Transient mass and energy transport equations are solved along with reaction kinetics equations using finite element method. Charging and discharging processes are investigated. The effect of geometrical and operational parameters including the material properties on overall storage and retrieval process has been studied. It was shown that the bed porosity plays a dominant role in the reactor performance. The increase in the bed porosity improves the reactor performance for both charging and discharging mode.
Viscoelectric Effect on the Electroosmotic Flow in Nanochannels With Heterogeneous Zeta Potentials
Authors: Jimenez Edson M. , Méndez Federico , Escandón Juan P.
Published: January 2019

In the present work, we realize a study about the influence of viscoelectric effect on the electroosmotic flow of Newtonian fluids in nanochannels formed by two parallel flat plates. In the problem, the channel walls have heterogeneous zeta potentials which follow a sinusoidal distribution; moreover, viscoelectric effects appear into the electric double layers when high zeta potentials are considered at the channel walls, modifying the fluid viscosity and the fluid velocity. To find the solution of flow field, the modified Poisson-Boltzmann, mass conservation and momentum governing equations, are solved numerically. In the results, combined effects from the zeta potential heterogeneities and viscosity changes yields different kind of flow recirculations controlled by the dephasing angle, amplitude and number of waves of the heterogeneities at the walls. The viscoelectric effect produces a decrease in the magnitude of velocity profiles and volumetric flow rate when the high zeta potentials are magnified. Additionally, the heterogeneous zeta potentials at the walls generate an induced pressure on the flow. This investigation extend the knowledge of electroosmotic flows under field effects for future mixing applications.
The Effects of Layer-by-Layer Thickness and Fiber Volume Fraction Variation on the Mechanical Performance of a Pressure Vessel
Authors: Özaslan Emre , Yetgin Ali , Coşkun Volkan , Acar Bülent , Olğar Tarık
Published: January 2019

Due to high stiffness/weight ratio, composite materials are widely used in aerospace applications such as motor case of rockets which can be regarded as a pressure vessel. The most commonly used method to manufacture the pressure vessels is the wet filament winding. However, the mechanical performance of a filament wound pressure vessel directly depends on the manufacturing process, manufacturing site environmental condition and material properties of matrix and fiber. The designed ideal pressure vessel may not be manufactured because of the mentioned issues. Therefore, manufacturing of filament wound composite structures are based on manufacturing experience and experiment. In this study, the effect of layer-by-layer thickness and fiber volume fraction variation due to manufacturing process on the mechanical performance was investigated for filament wound pressure vessel with unequal dome openings. First, the finite element model was created for designed thickness dimensions and constant material properties for all layers. Then, the model was updated. The updated finite element model considered the layer-by-layer thickness and fiber volume fraction variation. Effects of the thickness and fiber volume fraction on the stress distribution along the motor axial direction were shown. Also hydrostatic pressurization test was performed to verify finite element analysis in terms of fiber direction strain through the motor case outer surface. Important aspects of analyzing a filament wound pressure vessel were addressed for designers.
Downwind Two-Bladed Wind Turbine Aerodynamic Performance Evaluation Implementing Actuator Line Model
Authors: Henao Sebastian , Benavides Aldo G. , López Omar D.
Published: January 2019

The current trend in the wind power market is to develop large diameter rotors in order to maximize the power extraction from the wind. Those rotors exhibit issues related to blade deflection and structural integrity that can be mitigated implementing design variations that were present on the early wind turbine designs, such as rotors with less than three blades located behind the tower in downwind configuration. This work assesses the aerodynamic performance of a downwind two-bladed wind turbine based on CFD simulations coupled with the Actuator Line Model (ALM). This design is compared with the MEXICO project upwind three-bladed wind turbine, for which experimental data is available. The simulations showed good agreement with measurements especially upstream the rotor and for higher inlet velocities. Furthermore, the downwind configuration was successfully modeled using ALM and the performance prediction of the turbines was physically accurate since realistic variations were obtained between the evaluated wind turbines and none of their performance coefficients exceeded Betz theoretical limit.
Developing an Advance Tire Hydroplaning Model Using Co-Simulation of Fully Coupled FEM and CFD Codes to Estimate Cornering Force
Authors: Nazari Ashkan , Chen Lu , Battaglia Francine , Taheri Saied
Published: January 2019

Hydroplaning is a phenomenon which occurs when a layer of water between the tire contact patch and pavement pushes the tire upward. The tire detaches from the pavement, preventing it from providing sufficient forces and moments for the vehicle to respond to driver’s control inputs such as breaking, acceleration and steering. This work is mainly focused on the tire and its interaction with the pavement to address hydroplaning. Fluid Structure Interactions (FSI) between the tire-water-road surfaces are investigated through two approaches. In the first approach, the coupled Eulerian-Lagrangian (CEL) formulation was used. The drawback associated with the CEL method is the laminar assumption and that the behavior of the fluid at length scales smaller than the smallest element size is not captured. As a result, in the second approach, a new Computational Fluid Dynamics (CFD) Fluid Structure Interaction (FSI) model utilizing the shear-stress transport k-ω model and the two-phase flow of water and air, was developed that improves the predictions with real hydroplaning scenarios. Review of the public literature shows that although FEM and CFD computational platforms have been applied together to study tire hydroplaning, developing the tire-surrounding fluid flow CFD model using Star-CCM+ has not been done. This approach, which was developed during this research, is explained in details and the results of hydroplaning speed and cornering force from the FSI simulations are presented and validated using the data from literature.
A Correlation for Heat Transfer to Two-Component Gas-Liquid Flowing in Vertical Channels
Authors: Shah Mirza M.
Published: January 2019

A general correlation is presented for heat transfer during flow of gas-liquid mixtures flowing in vertical channels prior to dryout. It has been verified with a wide range of data that include upwards and downwards flow in heated and cooled tubes, annuli, and rectangular channels. The data are from 19 studies and include 14 gas-liquid mixtures with a very wide range of properties. The parameters include pressure 1 to 6.9 bars, temperature 16 to 115 oC, liquid Reynolds number from 2 to 127231, superficial gas and liquid velocities up to 87 and 13 m/s respectively, and ratio of superficial gas and liquid velocities 0.03 to 1630. The 1022 data points are predicted by the new correlation with mean absolute deviation (MAD) of 18.1 %. Several other correlations were also compared to the same data and had much larger deviations.
The Effect of a Spanwise Body Force on Skin-Friction Reduction and its Connections to Low-Drag States in Turbulent Flow
Authors: Hafner Thomas A. , Park Jae Sung
Published: January 2019

Reducing turbulent skin-friction drag is a subject of great interest due to the potential benefits. These benefits are reflected in applications such as aircraft and vehicles for which skin-friction drag constitutes a significant fraction of the total drag. For example, commercial airliners have up to 50% of their fuel consumption associated with turbulent drag. Thus, any drag reduction would result in substantial savings with regards to the operational cost of the airline industry. In this study, we investigated the effects of a spanwise body force on reducing skin-friction drag in turbulent channel flows. To this end, we performed direct numerical simulations (DNS) of turbulent channel flows with an applied spanwise body force. The body force consists of four control parameters: the amplitude of excitation, penetration depth, period of oscillation, and wavelength. A series of DNS were performed to investigate the effect of these parameters on drag reduction. We observed different levels of drag reduction and the magnitude of skin-friction varied considerably. The DNS results showed that the skin friction is reduced by as much as 20% with values for penetration lengths from 0.03 to 0.09 and periods between 10 and 20. An optimal combination of the four adjustable control parameters is yet to be concluded. In addition to skin-friction reduction, we found an intriguing observation from a time series of wall shear stress. When the wall shear stress is sufficiently lower than its mean value (i.e., low-drag intervals), the spanwise body force appears to significantly affect turbulent dynamics to make the wall shear stress not as chaotic as in other intervals. Specifically, the standard deviations of the peak-to-peak magnitudes of the wall shear stress during low-drag intervals are significantly lower than that of other intervals. This observation could be crucial in that it may lead to a further fundamental understanding of the drag reduction process. Moreover, it may aid in the development of more effective control schemes by way of anticipating that low-drag intervals are promising targets for drag reduction.
Development of the Pneumatic Non-Contact Holder
Authors: Tsukiji T. , Kondo R.
Published: January 2019

Pneumatic non-contact holders have been put to practical use for transporting semiconductor wafers and foodstuffs (hereafter “workpiece”) in manufacturing processes. The two main types of pneumatic non-contact holder are the Bernoulli and vortex types. In our previous study, we used a Bernoulli-type non-contact holder to achieve full non-contact holding by attaching a diffuser, but the workpiece underwent irregular rotation. With a vortex-type holder, this rotation could be prevented by generating two vortex flows with opposite rotations. However, the workpiece tended to slip away from the holder so that a guard structure was required, which introduced point contact with the guard into the holding process. This study’s purpose was to create a holder that is fully non-contact and does not cause workpiece rotation. By combining both the Bernoulli and vortex types, we succeeded in holding a workpiece without both contact and rotation.
Evaluation Method for Performance of SiC Power Module by Electro-Thermal-Anisotropic Stress Coupled Analysis
Authors: Kato Mitsuaki , Goryu Akihiro , Kano Akira , Takao Kazuto , Hirohata Kenji , Izumi Satoshi
Published: January 2019

Silicon carbide (SiC) has attracted increasing attention as a material suitable for use with high breakdown voltages and at high temperatures. The effects of residual stress and thermal stress on the electrical properties are therefore a matter of growing concern. To analyze the effects, multi-physics simulation is required. The aim of this study is to present an evaluation method for SiC power modules by electro-thermal-stress coupled analysis. In this analysis, we investigate the relationship among mechanical stress, temperature, and electrical resistance in 4H-SiC MOSFET. To investigate the relationship, we used a four-point bending system that is capable of applying uniaxial stress to the SiC device. We prepared two kinds of test specimens with the uniaxial stress direction of four-point bending coinciding with the 〈112̄0〉 and 〈11̄00〉 direction of SiC. To associate the four-point bending load with the stress components in the SiC device, the four-point bending test was simulated by the finite element method. Tensile or compressive load was applied to two types of test specimens, and the internal stress of the SiC device was determined. To determine the internal stress during operation and mounting, the simple module model was also simulated by the structural analysis method. The internal stress was simulated from mounting temperature to the operating temperature. An electrical circuit and thermal circuit were constructed for the DC-DC converter in the above-described module for the coupled analysis method. The relationship among mechanical stress, temperature, and electrical resistance was incorporated into the additional resistance of the MOSFET in the electrical circuit. When an isotropic stress from −500 to 1400 MPa was applied with the SiC under the oxide film in the one parallel DC-DC converter, the change in the power conversion efficiency was about 0.16%. This indicates that our proposed method is a useful simulation method for SiC power modules.
Computational Study of Onset Dynamics in Neuron-Spiking With Threshold Adaptation
Authors: Kavan Loabat S. , Wadkar Abhijeet , Asokanthan Samuel F.
Published: January 2019

Magnetic Seizure therapy (MST) is emerging as a treatment for patients suffering from severe depression where an induced current due to an external electromagnetic field is employed. This procedure can only be considered effective when sufficient induced current activates the neurons in the prefrontal cortex. Computer simulation of MST is essential to provide better insight of this procedure and to supplement the clinical trials. To this end, an understanding of transmission of electric impulse through the nerve is considered essential. Stochastic impulse spike sequences are trigged when membrane potential crosses a threshold value. Quantitative numerical predictions employing a mathematical model and induced current defined via Ornstein Uhlenbeck (OU) process predict that both the linear steady-state and rectified models provide adequate threshold adaptation while the rectified model exhibits superior spiking behavior. The present study when combined with suitable numerical simulation of electromagnetic induction is envisaged to aid the MST clinical treatment.
Calibration of External Heat Transfer Coefficients During Cooling of a Partially-Filled Water Tank Using Measured Temperature-Time Data
Authors: Ramesh Vishal , Mazumder Sandip , Matharu Gurpreet , Vaishnav Dhaval , Ali Syed , Lawrence Don , Desai Jatin , Ehteshami Mohsen
Published: January 2019

A combined Computational Fluid Dynamics (CFD) and experimental approach is presented to determine (calibrate) the external convective heat transfer coefficients (h) around a partially-filled water tank cooled in a climactic chamber. A CFD analysis that includes natural convection in both phases (water and air) was performed using a 2D-axisymmetric tank model with three prescribed average heat transfer coefficients for the top, side and bottom walls of the tank. The commercial CFD code ANSYS-Fluent™, along with User-Defined Functions (UDFs), were utilized to compute and extract temperature vs. time curves at five different thermocouple locations within the tank. The prescribed h values were then altered to match experimentally obtained temperature-time data at the same locations. The calibration was deemed successful when results from the simulations exhibited match with experimental data within ±2°C for all thermocouples. The calibrated h values were finally used in full-scale 3D simulations and compared to the experimental data to test their accuracy. Predicted 3D results were found to agree with experimental results within the error of the calibration, thereby lending credibility to the overall approach.
Measurements of the Contact Angles for Various Fluids Which Are Widely Used in the Oilfields to Improve Oil Recovery
Authors: Elsharafi M. , Vidal K. , Thomas R.
Published: January 2019

Contact angle measurements are important to determine surface and interfacial tension between solids and fluids. A ‘water-wet’ condition on the rock face is necessary in order to extract oil. In this research, the objectives are to determine the wettability (water-wet or oil-wet), analyze how different brine concentrations will affect the wettability, and study the effect of the temperature on the dynamic contact angle measurements. This will be carried out by using the Cahn Dynamic Contact Angle. Analyzer DCA 315 to measure the contact angle between different fluids such as surfactant, alkaline, and mineral oil. This instrument is also used to measure the surface properties such as surface tension, contact angle, and interfacial tension of solid and liquid samples by using the Wilhelmy technique. The work used different surfactant and oil mixed with different alkaline concentrations. Varying alkaline concentrations from 20ml to 1ml were used, whilst keeping the surfactant concentration constant at 50ml.. It was observed that contact angle measurements and surface tension increase with increased alkaline concentrations. Therefore, we can deduce that they are directly proportional. We noticed that changing certain values on the software affected our results. It was found that after calculating the density and inputting it into the CAHN software, more accurate readings for the surface tension were obtained. We anticipate that the surfactant and alkaline can change the surface tension of the solid surface. In our research, surfactant is desirable as it maintains a high surface tension even when alkaline percentage is increased.
Numerical Modeling and Analysis of Nonlinear Dynamic Response for a Bolted Joint Beam Considering Interface Frictional Contact
Authors: Li Dongwu , Xu Chao , Wang Dong , Wen Lihua
Published: January 2019

For an assembled structure with many bolted joints, predicting its dynamic response with high fidelity is always a difficult problem, because of the nonlinearity introduced by friction contact between jointed interfaces. The friction contact results in nonlinear stiffness and damping to a structure. To realize predictive simulation in structural dynamic design, these nonlinear behaviors must be carefully considered. In this paper, the dynamics of a multi-bolt jointed beam is calculated. A modified IWAN constitutive model, which can consider both tangential micro/macro slip and nonzero residual stiffness at macroslip phase, is developed to model nonlinear contact behaviors due to joint interfaces. A whole interface element integrating the proposed constitutive model is developed. The element is used to model the nonlinear stiffness and damping caused by bolted joints. The interface element is placed between the two contact interfaces. The other part of the beam is modeled by linear beam elements. A Matlab code is developed to realize the proposed nonlinear finite element dynamic analysis method. A hammer impact experiment for the bolt-jointed beam is conducted under different excitation force levels. The calculated nonlinear numerical results are compared with experimental results. It is shown that the effect of joint nonlinearity on structural dynamics can be observed from the response predicted by the proposed method. The numerical results agree well with the experimental results. This work validates the necessary of using nonlinear joint model for dynamic simulation of jointed structures.
Coupling Immunofluorescence and Optoelectrokinetic Technique for Escherichia Coli Detection and Quantification in Water
Authors: Ozeh Uzumma O. , Nnanna A. G. Agwu , Ndukaife Justus C.
Published: January 2019

At least 2 billion people worldwide drink water from sources contaminated with feces, in other words, sources contaminated with E. coli. The traditional method for detecting E. coli, among other limitations, detects only culturable bacteria and takes about 24–48 hours to yield a result. Consequently, the aim of this work is to develop a rapid diagnostic procedure for E. coli by combining immunofluorescence and optoelectrokinetic patterning to specifically target and sensitively trap the whole organism. This is to ensure the populace have timely access to sustained “E. coli-free” water for both domestic and recreational activities.

The procedure involves conjugation of streptavidin functionalized superparamagnetic fluorescent micro-beads with biotin-labelled anti-E. coli polyclonal antibody. The conjugate is introduced into a water sample containing E. coli among other contaminants, where it specifically and sensitively targets the bacteria in the sample solution which is quantified using an optoelectrokinetic patterning technique by introducing the targeted organism in a fabricated microfluidic chip and trapping it with an application of both laser beam and AC electric field simultaneously. Preliminary experiments have shown that increasing concentrations of E. coli in the microfluidic chamber varies directly with the electrical resistance of the entire system. This on-going research has the potential of sensitively isolating E. coli from a large pool of organic and inorganic contaminants in water in less than 4 hours.
Uncertainty Optimization Design of Vehicle Wheel Made of Long Glass Fiber Reinforced Thermoplastic
Authors: Hu Daijun , Shan Yingchun , Liu Xiandong , Chai Weihao , Wang Xiaoyin
Published: January 2019

The use of automobile lightweight is an effective measure to reduce energy consumption and vehicle emissions. The utilization of high-performance composite materials is an important way to achieve lightweight vehicles technically. The advantages of using thermoplastic composite wheels are: easy to form, high manufacturing efficiency, low cost and easy to recycle. This leads to broader application prospects. Taking composite anisotropy into consideration, the mechanical performance of a wheel made of long glass fiber reinforced thermoplastic (LGFT), is analysed using the finite element method (FEM). This is done by placing the wheel under a bending fatigue load simulation. According to the simulation results, the sample database is established by orthogonal experimental method on the Isight platform, and the approximate model is established by the Response Surface Methodology (RSM). Based on this model, uncertainty optimization analysis is then conducted on the wheel’s design using Sigma Principle whereby the optimization target is the mass minimization. The maximum deformation of the wheel and the stress on both sides of the spoke will serve as constraint conditions and the key dimension parameters of the wheel model will be taken as the design variables. The uncertainty optimization is based on the Sigma criterion, taking into consideration the wheel’s geometry and property-fluctuation materials. The feasibility of design schemes is then verified after comparison analysis between the optimization results and the simulation results obtained. The result shows that compared with deterministic optimization, though the weight of the wheel has slightly increased, the uncertainty optimization based on the Sigma criterion is much more robust and the reliabilities of the three constraints are all above 6 Sigma. The resulting optimized LGFT wheel weighs 5.28kg, which has a 5.5% more loss in weight than the initial target and is also 25.6% lighter than the counterpart wheel which is made of aluminum alloy. The desired design results is now achieved with this lightweight effect.
About the Immediate Shift From Large-Sized Machine Boeing 747 to Boeing 777
Authors: Shishido Masako
Published: January 2019

For aircraft, Airport facilities are indispensable infrastructure. Looking at the arrival and departure capabilities of Haneda / Narita airport which is said to be a crowded airport in japan, in 1992, Haneda Airport got 210,000 a year (40 departures / hours at departure and arrival), Haneda airport reached 130,000 a year, Totaling 340,000 times in total. In 2004 (2014), Haneda Airport had 447 thousand times and Narita airport had 300 thousand times, a total of 747 thousand times, showing more than doubling(1). Business opportunities of the air craft industry are expanding due to due to the start of sharing of Haneda’s new runway and new international passenger terminal. The development of modern IT promotes convenient air development of computers is greatly related to the transition from the Boeing 747 which was the theme this time to Boeing 777 promptly. I decided to investigate the fact that cooperation customers is changing in Boeing 747 and Boing 777.
Applying a Radiative Heat Transfer Finite-Volume Methodology to a Geometrically Complex Furnace
Authors: Lygidakis Georgios N. , Leloudas Stavros N. , Nikolos Ioannis K.
Published: January 2019

Considering that radiative heat transfer is encountered in many engineering and industrial applications, significant efforts have been applied during the last decades for the development of relevant numerical methodologies. In this study, such an inhouse academic radiative heat transfer method is presented in brief, whereas it is evaluated against a geometrically complex furnace. The proposed solver depends on the time-dependent RTE (Radiative Transfer Equation) aiming to predict radiative heat transfer in general enclosures through absorbing, emitting, and either isotropically or anisotropically scattering gray media. Spatial discretization is obtained with a node-centered finite-volume method on three-dimensional tetrahedral or hybrid unstructured grids. Increased accuracy is succeeded with a second-order scheme. The final steady-state solution is obtained with an iterative procedure, based on an explicit second-order accurate in time four-stage Runge-Kutta method and accelerated mainly via parallel processing and an agglomeration multigrid scheme. The proposed solver is assessed against an experimental three-dimensional furnace case, incorporating many of the geometric complexities encountered in industrial furnace systems. The predicted numerical results, regarding the incident wall fluxes, are compared with the available experimental data, revealing a satisfactory agreement and consequently demonstrating the proposed code’s potential to predict accurately radiative heat transfer in complex enclosures.
Blended Learning by Gamification in a Second-Year Introductory Engineering Design Course
Authors: Sharunova Alyona , Ead Ahmed , Robson Christopher , Afaq Misha , Mertiny Pierre
Published: January 2019

With the rapid development of engineering and new demands of contemporary employers, post-secondary institutions have to adapt, improve and enhance engineering curricula to ensure that recent graduates possess appropriate levels of technical and professional skills and multilateral abilities for a successful start in industry. As industrial technologies, tools, and processes evolve, so must teaching methodologies and approaches, which significantly changes the structure of engineering courses. To ensure that students not only master technical knowledge but also develop their professional, interpersonal, cognitive and computer skills, engineering curricula have begun to shift from a classic instruction format to a blended learning format. Blended learning, the strategy of combining regular face-to-face instruction with online learning and/or other out-of-class-activities, is increasingly used in post-secondary education and disciplines and can take different forms depending on the course needs and desired learning outcomes. This paper reviews the recent implementation of blended learning in the form of gamification of a second-year introductory engineering design course using a commercial online learning platform. The reasoning, methodology, process and the results of student surveys before and after the online game are discussed along with suggested improvements.
Utilization of Wavy Toolpath in Single-Point Incremental Forming
Authors: Grimm Tyler J. , Ragai Ihab , Roth John T.
Published: January 2019

Incremental forming (IF) is a sheet material forming method which utilizes a hemispherically tipped tool to form material. The tool is typically CNC controlled along a path which outlines the contours of the final geometry. The most common toolpaths used during forming are the spiral and step-down paths. Few variations of these toolpaths currently exist.

A novel toolpathing strategy is proposed herein. This toolpath forms a wave-like path in order to mimic the effects of vibration-assisted tooling; however, with much greater control. A variation of this strategy in which the tool does not lose contact with the surface of the part throughout its path was tested. This method has been found to be an effective approach for improving the surface variability of the final part.
Effective Design Team Composition Using Individual and Group Cognitive Attributes
Authors: Fritz Kaitlyn , Deschenes Line , Pandey Vijitashwa
Published: January 2019

Engineering design is typically a team effort. Design teams frequently need to push technical boundaries to solve the most relevant challenges faced by our society. A significant area of research across multiple fields of investigation, including engineering, is the understanding and use of an individual’s cognitive attributes in the process of assembling productive teams. This research proposes an approach to assembling an engineering design team by first defining the desirable cognitive attributes in the team members. Subsequently, based on individual cognitive profile assessments along these attributes, an exhaustive list of possible design teams is investigated based on their cumulative attribute level. We compare the performance of two teams predicted to perform at different levels, and our results verify the differences between the observations of team interactions and the quality of designs produced. In addition to self-assessments, we also investigate the brain activity of the respondents using electroencephalography (EEG) to evaluate performance in an individual and a team setting. This analysis intends to highlight the characteristics of an individuals’ brain activity under different circumstances to reveal if these characteristics contribute to the success of a design team. EEG data revealed observations such as correlation between raw amplitude and level of team contribution, a higher variation in the channel power spectral density during individual versus team tasks, and a degradation of alpha activity moving from individual to group work. The results of this research can guide organizations to form teams with the necessary cognitive attributes to achieve the optimum design solution.
Rotating Film Cooling Performance of the Hole Near the Leading Edge on the Suction Side of the Turbine Blade
Authors: Zhou Zhi-yu , Li Hai-wang , Wang Hai-chao , Zhao Guo-qin , Han Feng , Wu Min
Published: January 2019

This paper reports the experimental and numerical studies on the effects of rotating speed and blowing ratio on the film cooling performance of the hole near the leading edge on the suction side of the turbine blade. The chord and height of the blade are 60mm and 80mm respectively. The film hole with diameter of 0.8mm is located in the mid span on the suction side at axial location of 8%. The injection angle of the hole is 45° to the suction surface of the blade and is nearly perpendicular to the axial direction. Both experimental and numerical studies were carried out with rotating speeds of 300rpm, 450rpm and 600rpm, and with blowing ratios of 0.5, 1.0, 1.5 and 2.0. CO2 was used as the coolant. Experimental data was measured by applying the Thermochromic Liquid Crystal (TLC) technique and the Stroboscopic Imaging Technique. Mainstream and coolant were heated to 308K and 318K respectively. Numerical studies were performed to assist the analysis of the experimental results. The SST turbulence model was applied in the simulations. Results show that the film cooling performance of the hole near the leading edge is different from that of the hole further downstream on the suction side. This is because the direction of the jet is nearly perpendicular to the axial direction, which increases the effect of the Coriolis force. Besides, the mainstream from leading edge also has effects on film cooling performance. With the increase of the blowing ratio, the film coverage area and spatially averaged film cooling effectiveness increase first and then decrease. The maximum film coverage and averaged film cooling effectiveness appear at blowing ratio of 1.0 and rotating speed of 300rpm. Moreover, the upward deflection angle of the film trajectory increases slightly with the increase of the blowing ratio. Higher rotating speed intensifies the deflection of the film trajectory. Therefore, the film coverage and the averaged film cooling effectiveness decrease rapidly.
Numerical Investigation on Effects of Structure Parameters on Acceleration Noise of Involute Spur Gear System Under Different Operation Conditions
Authors: Wei Changyin , Wang Jingang , Liu Hai , Chen Yong , Ma Kunqi , Yu Hanzhengnan
Published: January 2019

The involute spur gear system has been widely utilized in the mechanical transmission domain, and the control of the acceleration noise of the involute spur gear system has become the key technology to solve the NVH performance of the power transmission system, especially in the automobile industry. In the process of the gear meshing, the unavoidable acceleration noise of the involute spur gear system is mainly caused by the meshing stiffness and error excitation due to the structural parameters. Therefore, the investigation on the effects of structure parameters on acceleration noise of the involute spur gear system is necessary.

In this paper, the numerical model for predicting the acceleration noise of the involute spur gear system has been established. The simulation results of the acceleration noise were compared with the experimental results, and the errors between these two results were only 2.9%, within permission.

The effects of structure parameters including base pitch error and pressure angle on the acceleration noise of the involute spur gear system have been discussed. Results showed that increasing the base pitch error, the acceleration noise level of the involute spur gear increased, and the gap of the noise level between different base pitch errors narrowed according to the increase of gear load and rotation speed. Increasing the pressure angle also increased the acceleration noise level, however, the gap between different pressure angles remained the same regardless the variations of gear load and rotation speed, which was different than the variations of base pitch error.
Design and Development of a Low-Cost Roof Top Solar Ventilator
Authors: Shanmugam Ragavanantham , Vellaisamy Umayakumar , Balasubramaniam Karthikeyan , Mani Sathishkumar
Published: January 2019

In hot summer, the sun rays strike the roof surface and heat up the enclosed attic. Passive vents (Soffit or Gable) allow some circulation of fresh air. Presently, in India, passive Whirlybird is predominantly used for ventilation purposes, which spins and sucks up the warm air and forces it out upwards through the vent on the roof. Since it depends mainly on the natural wind velocity, it’s efficiency to cost ratio is very low. Also, the accumulation of dust particles has a deleterious effect on the performance and life of the unit. Hence, in this work, a roof top solar ventilator has been designed and developed at low cost to address the above-mentioned problems. This unit has a high-performance brushless DC motor, an adjustable solar panel to achieve optimal solar exposure and it blends seamlessly into roof. The solar panel powers the fan through the motor, thereby increasing the air circulation through the vent. This increased air circulation provides the required pressure to force the hot air out from the attic. During hot summer, the difference in temperature between the floor and the ceiling can reach 10–15 °C, leading to a constant heat pile up in the attic and this system can limit the temperature of the attic to 40°C. In winter season, moist air present inside the house warms up, rises and collides with the cold air entering through the roof. This provides a mixed circulation that prevents the cold air from entering the roof and also reduces freezing of snow on the roof surface. Further, it keeps the inside space cooler and drier. Since this ventilator operates on renewable energy source, it is a simple and feasible solution that is environmentally friendly at low-cost. This provides healthy, energy efficient homes and work spaces as it reduces the usage of air conditions and heaters. A comparative study on the performance, life and cost of both the existing and the newly developed ventilators has been made and the same is reported.
A Novel Microlaser Based Plasmonic-Polymer Hybrid Resonator
Authors: Manzo Maurizio , Schwend Ryan
Published: January 2019

Whispering gallery mode (WGM) resonators exhibit high quality factor Q and a small mode volume; they usually exhibit high resolution when used as sensors. The light trapped inside a polymeric micro-cavity travels through total internal reflection generating the whispering gallery modes (WGMs). A laser or a lamp is used to power the microlaser by using a laser dye embedded within the resonator. The excited fluorescence of the dye couples with the optical modes. The optical modes (laser modes) are seen as sharp peaks in the emission spectrum with the aid of an optical interferometer. The position of these optical modes is sensitive to any change in the morphology of the resonator. However, the laser threshold of these microlasers is of few hundreds of microjoules per square centimeter (fluence) usually. In addition, the excitation wavelength’s light powering the device must be smaller than the microlasers size. When metallic nanoparticles are added to the microlaser, the excited surface plasmon couples with the emission spectrum of the laser dye. Therefore, the fluorescence of the dye can be enhanced by this coupling; this in turn, lowers the power threshold of the microlaser. Also, due to a plasmonic effect, it is possible to use smaller microlasers. In addition, a new sensing modality is enabled based on the variation of the optical modes’ amplitude with the change in the morphology’s microlaser. This opens a new avenue of low power consumption microlasers and photonics multiplexed biosensors.
Technology on Trial: The Social Framework of Safe Design
Authors: Munsell W. P.
Published: January 2019

Blocked by novel judicial defenses that deprived them of the common law remedies that the general public enjoyed, workers agitated for decades until growing political pressure led employers and the courts to accept worker’s compensation in America at the beginning of the twentieth century. Two remarkable side-effects of the Worker’s Compensation Acts were the ignition of the safety movement and the reformulation of tort law in regards to technological harms. These changes came just as some of the dangers formerly reserved for industrial workers began to be visited upon consumers in the form of new, complex, and mass-produced products. Safety-minded engineers joined together to reassess the role of technology in accident-related injury, creating a new framework for design that shed old deterministic assumptions about operator behavior. Likewise, the legal community re-imagined tort law in view of a broad no-fault worker’s compensation system. The legal formulation culminated in a strict products liability regime in 1964, and a sea change in the social status of technology itself. But these two revolutionary conceptions, both oriented toward the protection of the user, are not equal: modern legal disputes serve to expose the disconnect between the engineering and legal frameworks of safe design.
Toward a Contactless Hydrokinetic Energy Harvester: A Computational Magnetic Field Estimation
Authors: Tsakyridis Georgios , Xiros Nikolaos I. , Bernitsas Michael M.
Published: January 2019

Magnetic levitation (maglev) concepts are applied to a variety of industries such as the automotive, aerospace, or energy in order to accomplish different tasks: suspension and propulsion in maglev trains, rocket propulsion and spacecraft attitude control, centrifuge of nuclear reactors. In this paper, maglev is implemented in environmentally friendly hydrokinetic energy harvesting to achieve contactless bearing, thus, minimizing friction and improving efficiency. Generally, maglev systems exhibit higher efficiency and reduced maintenance while providing longer lifetime and higher durability when appropriate engineering design and control are applied. A Flow Induced Oscillation (FIO) energy-harvesting converter is considered in this work. To minimize friction in the support of the cylinder in FIO (vortex induced vibrations and galloping) due to high hydrodynamic drag, a maglev system is proposed. In the proposed configuration, a ferromagnetic core (element 1), of known dimensions, is considered under the effects of an externally imposed magnetic field. A second ferromagnetic element, of smaller dimensions, is then placed adjacent to the previous considered core. This particular configuration results in a non-homogenous magnetic field for element 1, caused by dimensional disparity. Specifically, the magnetic flux does not follow a linear path from the ferromagnetic core to element 2. A general electromagnetic analysis is conducted to derive an analytical form for the magnetic field of element 1. Subsequent numerical simulation validates the obtained formula. This distinct expression for the magnetic field is valuable towards calculating the magnetic energy of this specific configuration, which is essential to the design of the FIO energy harvesting converter considered in this work.