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Aircraft icing has long been a plague to aviation for its serious threat to flight safety. Recently, researches about a newly proposed deicing method based on Plasma Synthetic Jet Actuator (PSJA) have just started. To meet the requirements of in-flight deicing, structure of PSJA needs to be adjusted. This paper completed the detailed design and experimental validation of a novel plasma striker, which was a modified version of PSJA. Influences of mass of the moving part and rod shapes on the ice-breaking performances were also studied. Besides, a “conical-nosed rod configuration” was proposed. Its purpose was to ensure a good ice-breaking performance of the plasma striker on long ice, by generating a splitting failure. Results show that, though mass of the moving part was just several grams, ice-breaking performance was better when the mass was lighter. The rectangular rod could generate an elliptical circumferential crack, whose major axis was parallel to the direction of the long side of the rectangular rod. And the “conical-nosed rod” concept was verified to be able to generate a splitting crack which can spread completely to the far end of long ice, and the crack direction was parallel to edge line of the cone. In general, the plasma striker has the advantages of simple structure, low energy consumption, little harm to the flow field and the aircraft skin. Simulations will be carried out in future works to study in detail the working process of the plasma striker.

This paper describes the experimental validation of a CubeSat tether deployment design by air-bearing ground test and microgravity parabolic flight test. The tethered CubeSat mission includes two 1U CubeSats with a tape-type tether of 100 m. The tether will be deployed by pull with two CubeSats separating at a desired velocity. Various ground tests were performed to validate the designed separation velocity, estimate the internal friction force, and measure the deployed tether length. Finally, the engineering model of tether deployment system is validated by microgravity parabolic flight testing. The parabolic flight demonstrated the tether deployment system works as expected. By measuring the separation velocity of CubeSats in the parabolic flight, it reveals the internal friction is much less in the microgravity environment than the value measured on the ground.

The vibrations observed in internal combustion engines transfer to the Tail pipe via exhaust manifold. Such Vibrations cause failure of exhaust system. Two types of vibration can affect the exhaust manifold: the sonic pressure waves coming from the exhaust ports, and the vibration of the engine itself. Pressure wave vibrations are usually transparent, travelling through the exhaust system to either absorb into or cancel out in the muffler. These waves are harmonic, like the vibration of a speaker, but they are usually too minute to cause noise through component movement. Engine vibrations, on the other hand, can easily shake your complete exhaust system. Such cyclic loading of waves can cause component rattling or failure. This vibration failure occurs due to resonant frequencies occurring in defined frequency range. The ‘frequency match’ could lead to a response detrimental to the life of the structure.FEA techniques are proposed in this work to avoid resonance. Physical experimentation is proposed using FFT Analyzer. This work deals with the damping of such later mentioned vibration problems with a concept of CAE (Computer Aided Engineering). In this project we are analyzing the exhaust system under various conditions for modal (natural vibrations). Static and modal analysis of exhaust manifold has been performed using ANSYS 19 software along with experimental validation of manifold using FFT and impact hammer test. Different types of methods for reducing vibration of manifold are studied. After studying these methods and procedures for reducing a vibration, we conclude that, exhaust manifold concept 02 is more efficient by changing the geometry or adding proper stiffener for reducing vertical vibration which further increases the frequency response of component..

The aim of this study is to analyze the phase change material cooling performance integrated into heat sink experimentally. a paraffin wax as phase change material is used in this experiment and it placed under the heat sink with thickness 30mm , various power input at 11W,13W and 15W used in this experiment to generate heat at different levels also several fan speed at 15m/s,2.5m/s and 3.4m/s. the surface temperature of the heat sink is monitored over the time to evaluate the phase change material thermal performance . From the results ,temperature drop and the time lag in case of without PCM compared to with PCM shows the effect of cooling of adding PCM under low and high speeds of heat removal. It found that inclusion of PCM into heat sink with forced convection shows high temperatures drop up to 18 °C.

The development, modelling and testing of a novel, fuel-efficient hydraulic hybrid light truck is reported. The vehicle used a Digital Displacement® pump/motor and a foam-filled hydraulic accumulator in parallel with the existing drivetrain to recover energy from vehicle braking and use this during acceleration. The pump/motor was also used to reduce gear-shift times. The paper describes the development of a mathematical vehicle model and the validation of this model against an extensive testing regime. In testing, the system improved the fuel economy of the vehicle by 23.5% over the JE05 midtown drive cycle. The validated mathematical model was then optimised and used to determine the maximum fuel economy improvement over the diesel baseline vehicle for two representative cycles (JE05 midtown and WLTP). It was found that the hybrid system can improve the fuel economy by 24%–43%, depending on the drive cycle. When this was combined with engine stop-start, the system improved the fuel economy of the vehicle by 29%–95%, depending on the drive cycle.

An integrated kinetic model representing catalytic cracking of eugenol in a fixed bed reactor is developed. Eugenol, a major component of clove oil can act as the most potential bio additive fuel for improving the diesel quality thereby reducing the exhaust emission of the engine. The proposed integrated model includes four lump kinetic model which is plugged with catalyst deactivation model. The reactor design parameters are also included in the integrated model. The effectiveness of the proposed integrated model is compared with the conventional kinetic models and the results are presented. The proposed integrated model is validated against the real time data obtained by conducting an experiment in a real time setup with MoS2(Ni2P) Al-SBA-15(10) as the catalyst. The advantages of the proposed integrated model are highlighted.

The road transportation of critical components for cryogenic cryomodules is a challenging task. Indeed, the shipping and the handling of fundamental sub-assemblies can expose these components to harmful dynamic loads that can jeopardize their structural integrity. This article has the purpose of developing a finite element multibody model capable of assessing the acceleration on a test coupler for a cavity of the Single Spoke Resonator 1 subjected to a typical road transportation trip. A multibody model consisting of rigid bodies and finite element–imported flexible bodies has been created allowing a comparison of the simulated and experimental acceleration. Afterwards, an experimental on-road test, whose set-up is described in this article, has been carried out at Fermilab with instrumented components. Being able to effectively simulate and validate the dynamic effects on such sub-assemblies makes it possible, for the future, to simulate more complex structures subject to dynamic loadings, such as the entire cryomodules during shipping. Furthermore, the results from the simulations can be used to guide the design of new suspension systems suitable for the reduction mitigation of structural vibration during the road transportation of cryomodules.

Heterogeneous electrocatalysis is critical to many energy conversion processes. Theoretical and computational approaches are essential to interpret experimental data and provide the mechanistic understanding necessary to design more effective catalysts. However, automated general procedures to build predictive theoretical and computational frameworks are not readily available; specific choices must be made in terms of the atomistic structural model and the level of theory, as well as the experimental data used to inform and validate these choices. Here we outline some best practices for modelling heterogeneous systems and present examples in the context of catalysis at metal electrodes and oxides. The level of theory should be chosen for the specific system and properties of interest, and experimental validation is essential from the beginning to the end of the study. Continuous feedback and ultimate integration between experiment and theory enhances the power of calculations to elucidate mechanisms, identify effective descriptors and clarify design principles. Theoretical modelling is essential to deepen our understanding of heterogeneous electrocatalytic energy conversion processes, such as water splitting. Here, Sharon Hammes-Schiffer and Giulia Galli offer their perspectives on the best strategies for successfully studying such systems.

This study presents a novel cylindrical vane pump based on the traditional working principle. The efficiency of the cylindrical vane pump was verified by experimental validation and numerical analysis. Numerical analysis, such as kinematics analysis, was performed in Pro/Mechanism and unsteady flow-field analysis was performed using ANSYS FLUENT. The stator surface equations were derived using the geometric theory of the applied spatial triangulation function. A three-dimensional model of the cylindrical vane pump was established with the help of MATLAB and Pro/E. The kinematic analysis helped in developing kinematic equations for cylindrical vane pumps and proved the effectiveness of the structural design. The maximum inaccuracy error of the computational fluid dynamics (CFD) model was 5.7% compared with the experimental results, and the CFD results show that the structure of the pump was reasonable. An experimental test bench was developed, and the results were in excellent agreement with the numerical results of CFD. The experimental results show that the cylindrical vane pump satisfied the three-element design of a positive-displacement pump and the trend of changes in efficiency was the same for all types of efficiency under different operating conditions. Furthermore, the volumetric efficiency presented a nonlinear positive correlation with increased rotational velocity, the mechanical efficiency showed a nonlinear negative correlation, and the total efficiency first increased and then decreased. When the rotational velocity was 1.33[Formula: see text] and the discharge pressure was 0.68[Formula: see text], the total efficiency reached its maximum value.

A micro-meso-scale model is proposed to predict shear deformation and strength of textile-reinforced composites, considering shear non-linearity, strain-rate dependent elastic and visco-plastic beh...

A nitro group is a common fluorescence quencher, but its quenching efficiency can be easily affected by the surrounding environment. To date, there has been no systematic study on the effects of electron-withdrawing groups on the quenching efficiency of nitro groups. Herein, by virtue of experimental validation and theoretical calculations, we found that strong electron-withdrawing groups, such as pyridinium and dicyanovinyl groups, are detrimental to the quenching effect of nitro groups. Decreasing the electron-withdrawing ability could restore the nitro group’s quenching effect.

Combination of transient computational fluid dynamics simulations of a gas-fired heat treatment furnace and experimental validation were carried out to investigate the applicability of equilibrium ...

The aim of this study was to assess and quantify the effect of channel bed roughness on hydraulic jumps based on sound physical theories. Assuming that integrated bed shear stress due to surface roughness changes linearly with supercritical velocity, a novel definition for the shear force coefficient and for roller length were obtained. Experimental findings and Pearson's correlation verify that the developed equations perform reasonably well and they prove that a linear correlation assumption between integrated bed shear stress and supercritical velocity is valid for a Froude number between 1.1 and 9.8. The shear force coefficient is defined in terms of the Reynolds coefficient and the supercritical flow velocity is directly related to the modified Reynolds number. A new analytical equation for roller length as a function of the modified Reynolds number was also developed and validated by using data from the experimental study. HIGHLIGHTS The tendency of the Reynolds coefficient to approach a fixed value increases as the modified Reynolds number increases.; The results of this study showed that the modified Reynolds number is important in roller length analysis and cannot be ignored.; Pearson's correlation analysis showed a significant positive linear correlation between integrated bed shear stress and upstream supercritical velocity.

Covering with plastic film in fall and planting through the film in spring is an effective drought-resistance, potato-cultivation method. To achieve proper under-plastic-film, hill-drop potato seeding, the geometry of an existing five-link planter mechanism that is driven synchronously by two cranks rotating in the same direction has been refined through bivariate plots and numerical optimization. For this purpose, novel quantitative measures of the geometry of the crunode portion of the dibber-tip path have been introduced. The prototype planter mechanism described in detail elsewhere has then been configured according to the three optimum kinematic solutions obtained, and field tests have been carried out. All three configurations satisfied the imposed agronomic requirements of potato planting through the plastic film, with one setup performing better than the other two, and then a previously reported solution obtained through manually conducted optimization.

As a promising metalwork processing technology, electromagnetic induction heating (EMIH) method has been applied in dealing with bolted flange joints in turbomachinery. In this study, a 3-D finite element model of electromagnetic induction heating system for the bolted flange joint is established, and the specific governing equations are derived based on Maxwell’s principle. The alternately-coupled magneto-thermal analysis is carried out considering temperature-dependent material properties to obtain the temperature distribution, followed with the uncoupled thermal-mechanical analysis to acquire the axial stress and deformation in EMIH process. The magnetic induction intensity mainly concentrates at the inner wall region, attenuates seriously along the radial direction, and reduces to almost zero at the outer wall. Due to the skin effect, the heat transfers radially and axially outward, indicating a diamondlike-shaped development from the center to the surrounding region. The axial stress with and without initial pretension are also discussed respectively. Then the corresponding experiments are introduced and carried out to validate the reliability of numerical simulation results. By comparing the results of the center point of inner surface and outer surface, the numerical simulation is proved reliable with a 5∼10% reasonable deviation. Further, the induction heating process has been improved through the optimization method based on pattern search algorithm. By adopting the stepped input current density optimized in the study, the optimal thermal stress tends to be constant and the final heating time reduces by 20.5% in the safe range of stress.

Thermal deformation caused by temperature rise affects the contact status of bearings in motorized spindles. In turn, the change in the contact status will affect the temperature rise and thermal deformation of the system. However, the latter has been rarely focused on in the previous literature. Therefore, a thermal network model of motorized spindle is enhanced by considering the thermal–mechanical coupling effect. Then, an iterative method is presented to solve the coupled equations, and a temperature test rig of the motorized spindle is set up to verify the proposed model. The predicted results by the proposed model are compared with the experimental results and the predicted results by the previous model. The relative error between the predicted and experimental results at two test points decreases by 9.56% and 3.44%, respectively, after considering the thermal–mechanical coupling effect. The temperature changes the contact angle and contact load of the bearings, thereby causing changes in frictional heat and temperature field. Such changes cause the difference between the proposed and previous models. The comparison with the experimental results shows that the proposed model with thermal–mechanical coupling effect can obtain a more accurate temperature field than the previous model.

The interaction of guided waves with a material discontinuity is not well understood. This study investigates the propagation behavior of the fundamental Lamb-wave modes, the symmetric mode ( S0) and the anti-symmetric mode ( A0), upon interaction with welded joints of dissimilar materials. A plate with an intact AA6061-T6/AZ31B dissimilar joint was employed, and the interaction of the propagating wave with the material interface was scrutinized numerically and validated experimentally. Plane-wave approximation was also adopted to investigate the behavior of the symmetric modes, and its performance was compared to the numerical and experimental results. The effect of the angle of incidence on the reflection, transmission, and mode conversion of the incident modes was analyzed. The study was conducted as the excited Lamb wave propagated from AA6061-T6 to AZ31B (forward), and when the propagation direction was reversed (backward). Different techniques were developed to identify the in-plane and out-of-plane modes from the three-dimensional measurements and to separate wave reflections and transmissions of the joint. The fundamental shear-horizontal guided-wave mode ( SH0 mode) has evolved upon the interaction of the obliquely-incident Lamb-wave S0 mode with the interface. While the reflection of the SH0 mode from the joint was found to be well-pronounced, its transmission to the other material is extremely weak. The analytical solution, using plane-wave approximation, was accurate for predicting the behavior of the in-plane modes ( S0 and S0– SH0 modes). Despite the peaks appearing at the critical angle, the absolute values of the reflection coefficients of the studied modes have shown similar trends between the forward and the backward propagation directions. The total reflection of the excited wave, from the material interface, was not observed in any condition. The transmission coefficients of the S0 and A0 modes are almost constant until reaching very steep incidence angles [Formula: see text]. The results were experimentally validated on an intact AA6061-T6/AZ31B friction-stir-welded joint using an excitation frequency of 200 kHz. Measurements along the transmission and reflection directions were conducted using a three-dimensional scanning laser vibrometer. Experimental results showed very good agreement with both the analytical and the numerical ones.

With the gradual reduction of mineral resources, marine mining has increasingly been developed as a method of exploiting resources. However, the cutting efficiency of submarine mineral deposits requires additional improvement. Investigating the preferable cutting efficiency in marine mining, it is important to establish a theoretical model of predicting the peak cutting force for polymetallic sulfide. The polymetallic sulfide was taken from the floor of the Indian Ocean and maintained at constant temperature and humidity conditions during transportation. In the paper, some experiments were conducted to study the physicomechanical properties of polymetallic sulfide. And the cutting experiments were conducted to investigate the cutting force at room temperature and atmosphere pressure, preliminarily. Then, based on maximum tensile stress theory, the theoretical equation of predicting the peak cutting force was derived, and an improved high-precision theoretical model was established. The reliability and accuracy of this model was verified using the experimental data. Based on the improved theoretical model, the brittleness index and the cutting depth, which influenced the peak cutting force, were investigated. Results show that the established model improved the accuracy of predictions. The peak cutting force decreased with the increase of the brittleness index, but it increased with the increase of the depth, which followed the power-law pattern. The power-law coefficient was generally at 1-2. The experiments verified that this improved theoretical model and the related conclusions can predict the peak cutting force. It is significant for the design and study of conical picks and cutting mechanisms in marine mining.

In this research, stress measurement tests and advanced application algorithms based on computer-aided design and engineering (CAD and CAE) were developed and tested. The algorithm was put implemented through a case study on the strength-based structural design and fatigue analysis of a chassis. This algorithm consists of numerical and experimental methods and additionally includes material tests, three-dimensional CAD, a finite element method (FEM)-based analysis procedures, a structural optimization strategy, prototype production, stress tests, a fatigue analysis, and design verification procedures. In the optimization study targeting the optimum chassis weight/strength ratio, two chassis prototypes, with 8 mm and a 5 mm wall thicknesses, were manufactured to verify the structural analysis and experimental tests. As a result of the FEA analyses, for 20 kN, which is the target load value of the chassis, for chassis thicknesses t = 5 mm and t = 8 mm, the maximum tensile strength was obtained as 93 MPa and 83 MPa, respectively. Thus, the material gain of 35.85 kg mass was achieved, and chassis utilization efficiency was increased. This research provides a useful methodology for experimental and advanced CAE techniques, especially for further research on complex stress and deformation analysis of chassis that are desired to be of optimum weight/strength ratio.

Fracture modeling and experimental validation of Compacted Graphite Iron (CGI) specimens loaded under quasi-static conditions at room temperature are considered. Continuum damage mechanics coupled to plasticity is adopted to describe the evolution of damage. The damage production is based on a recently developed rate dependent damage evolution law, where the damage–plasticity coupling is modeled based on a damage driving energy that involves both stored energy and plasticity contributions. To describe ductile fracture accounting for stress triaxiality on the damage initiation, the inelastic contribution to the damage driving energy is controlled by the Johnson-Cook failure criterion. Three different damage models are defined based on elastic/inelastic damage driving energies. The damage models are validated against experiments on a set of notched specimens made of CGI with different notch geometries, where the global force-displacement curves and corresponding strain fields are obtained using digital image correlation technology. It is shown from the testing and the simulations that plastic strains generally need to be accounted for in order to properly describe the different failure processes of the CGI specimens. In addition, the ductile damage model is shown to more accurately predict the experimental force-displacement response as compared to the more simplistic stress drop, element deletion technique.

The buck converter is one of the DC/DC converters that are often used as power supplies and high energy conversion. These controllers are used in electronic devices to regulate the output voltage a...

Recently, there has been an ever-growing demand for multireceiver wireless power transfer (WPT) systems with a high power transfer efficiency. In this article, a novel optimization-based method is proposed to precisely determine the optimal resonant condition for multireceiver WPT systems in order to maximize the power transfer efficiency while satisfying all the rated power that can be differently required in each receiver module. The proposed method links the optimization module and the analysis module to iteratively update the design variables during optimization based on electric performance evaluated in the analysis module. After being verified with a “single-transmitter-to-a-single-receiver” WPT system which has a well-known resonance condition, the proposed method is applied to determine the optimal resonant condition for various “single-transmitter-to-multiple-receiver” WPT systems in both initial and disturbed configurations. The experimental validation demonstrates the performance and potential of the proposed method to compensate the coupling changes of multireceiver WPT systems.

A numerical investigation and experimental validation is performed to address deeper insights into the combined effect of shaped holes and Sand-Dune-shaped upstream Ramp (SDR) on enhancing the film cooling effectiveness, under a wide blowing ratio range (M = 0.25–1.5). Three kinds of holes (Cylindrical Hole (CH), Fan-Shaped Hole (FSH), and Crater-Shaped Hole (CSH)) are taken into consideration. The SDR shows an inherent affecting mechanism on the mutual interaction of jet-in-crossflow. It aggravates the lateral spreading of cooling jet and thus improves the film cooling uniformity significantly, regardless of film-hole shape and blowing ratio. When the blowing ratio is beyond 1.0, the combined effect of shaped holes and SDR on improving film cooling effectiveness behaves more significantly. It is suggested that FSH-SDR is a most favorable film cooling scheme. For FSH-SDR case, the spatially-averaged film cooling effectiveness is increased monotonously with the increase of blowing ratio, among the present bowing ratio range.

Based on a previous theoretical work, this paper focuses on the experimental validation of a sliding mode control (SMC) technique applied to an aerodynamic angular system (AAS). To do so, an aerodynamic experimental platform is presented together with its electronic interface and its closed-loop behavior generated by the aforementioned SMC strategy. The control performance is widely reviewed under different regulation tasks and gain variations. Experimental results prove that the control strategy guarantees a stable behavior. Moreover, the robustness of the control strategy is proved when the system is subject to the influence of external disturbances.

In a vehicle, bulbs called the P-group are responsible for warning other drivers or pedestrians and they are known as signal bulbs. Signal bulbs have been used to emit warning and hazard signs in parts such as brake lights, direction indicator, hazard lights (night vision) as well as tail bulbs and car park alarms. There has been limited researches on the photometric characteristics of these lamps, but a review of these studies revealed that no detailed research has yet been done on optimizing these characteristics, and there is a scientific gap. In this study, factors affecting the service life and luminous flux were evaluated by using Taguchi design of experiments method. The results showed that the two factors of weight percent composition of bubble filling neutral gases and the volumetric efficiency of gases injected into the bubble had the most influence on the target parameters. Experimental results showed that the optimum composition of neutral gases injected into the bulb bubble can extend the bulb service life to approximately 341 h, which is three times the service life of a bulb with the inappropriate composition of fill gases. Then the optimum state of the service life and the luminous flux were determined to meet the reference standards. Although the service life and luminous flux parameters were able to reach 341 h and 513 lumens in the maximized state, however, in the optimum state with satisfying reference standards, the service life and luminous flux were 330 h and 463 lumens, respectively. Then, the bulb bubble filling with inert neutral gases and its effect on the bulb service life was investigated. The results showed that if the volumetric efficiency of gas injection increased from the normal 75%–100%, the service life of the test lamps would be improved by about 10%.

The mismatch terminations are essential components in measurement setups of various active and passive microwave components. The main objective of such components is to provide a certain reflection level with a flat response over the operating bandwidth. The need for mm-wave mismatch terminations has increased due to the expansion of using mm-wave frequency ranges in future communication systems. The mm-wave bands are considered among the essential bands for the 5G communication system, which is expected to launch this year. In addition, the utilization of these bands is expected to increase in the 6G standard. In this article, we introduce a novel systematic procedure to design mismatch terminations. Moreover, two examples of mismatch terminations are designed with reflection levels of −9.5 and −12.7 dB, with the operating band of 32–38 GHz. For experimental validation, the proposed design is fabricated and measured, where a good agreement is achieved between the simulated and the measured response.

International audience; Objective - The potentialities of improving the penetration of millimeter waves for breast cancer imaging are here explored. Methods - A field focusing technique based on a convex optimization method is proposed, capable of increasing the field level inside a breast-emulating stratification. Results - The theoretical results are numerically validated via the design and simulation of two circularly polarized antennas. The experimental validation of the designed antennas, using tissue-mimicking phantoms, is provided, being in good agreement with the theoretical predictions. Conclusion - The possibility of focusing, within a lossy medium, the electromagnetic power at millimeter-wave frequencies is demonstrated. Significance - Field focusing can be a key for using millimeter waves for breast cancer detection.

It is of great significance to study the characteristics of low-temperature oxidation of coal in an adiabatic environment for the prediction and control of coal spontaneous combustion. Coal spontan...

The interaction between structures and walking humans is an important factor in vibration serviceability assessment of slender, lightweight, and low-damping structures. When on bridges humans form a human-structure system and interact with the structural vibration. The conventional vertical moving force (MF) model neglects human-structure interaction (HSI) effects. In contrast, a moving spring-mass-damper (MSMD) model is shown to have the potential to incorporate HSI effects leading to more accurate vibration response prediction. The MSMD model parameters have been much studied in biomechanics. However, the literature lacks an experimental calibration of the MSMD model parameters on a vibrating surface for vibration serviceability design and assessment purposes. Consequently, an experimental-numerical methodology is developed to calibrate the MSMD model parameters in the worst-case (resonance) scenario by matching measured and simulated vibration responses. To facilitate simple implementation of HSI effects into engineering practice, results of simulation using a calibrated equivalent moving force (EMF) model are also shown. The walking force on rigid surfaces along with vibration responses of two lively full-scale laboratory footbridges are measured for 23 test subjects by performing a total of 295 trials on the two structures. A parametric study is first performed on the MSMD model using the experimental results. The experimental results of the Monash footbridge are then used as the training dataset to extract optimal MSMD model parameters. The results from the Warwick footbridge are used to validate the model. The validation tests results show a considerable improvement in the vibration response prediction using both models. It was found that when walking in resonance with the bridge, the walker can be modelled to have natural frequency equal to the resonant frequency of the bridge, and that the damping ratio is larger for heavier walkers.

An improvement of a formerly proposed CFD-based methodology (base model) for the estimation of water evaporation rate in swimming pools is presented here. This base model achieved satisfactorily on...

This paper presents the methodology for design, analysis and experimental validation of Inconel-625 bellows for critical applications. By conducting a series of fatigue tests on Inconel-625 bellows, a curve representing the variation of fatigue life with equivalent stress range was generated. For critical applications such as in nuclear systems, the design of bellows needs to comply with the standard nuclear design codes such as ASME section-III. A design curve was generated by incorporating a factor of safety (FOS) on the experimental data. The experimental stress analysis approach given in ASME section-III/appendix-II was used to obtain the FOS. Design of the Inconel-625 bellows as per the generated fatigue design curve in the present work is simple and can be adopted by bellows suppliers. Also, the proposed method has required compliance with design codes such as ASME section-III. This paper also presents the design by analysis approach for design of nuclear bellows as per ASME section-III/NB).

Urea line heating system is critical for Selective Catalytic Reduction (SCR) aftertreatment system under low temperature environment. Traditionally, the Electronic Control Unit (ECU) motivates urea lines heating command and diagnostics directly. This paper illustrates a Controller Area Network (CAN)-based line heater architecture development for the SCR aftertreatment system, as well as the diagnostics generation. The CAN-based line heater diagnostics is validated on vehicle experimental with four different given cases. It can be seen from the validation results that the diagnostics logic and algorithm are reasonable, and the line heater failure modes could be detected correctly including open circuit, short circuit and inducement. In addition, the failure modes are able to set or clear for each of the urea lines according to the diagnostics logic. ECU and ECU1 could communicate well between each other by CAN. This study introduces a new line heater architecture for SCR aftertreatment system which is meaningful for the whole vehicle assembly, which could be considered in the real application in future.

This paper presents a feedback control design scheme for internal combustion engines with the exhaust gas recirculation and the variable valve timing. A second-order nonlinear dynamical model is pr...

The critical dimensions of magnet and its positional parameters in a permanent magnet synchronous motor (PMSM) are optimized using Taguchi method. L16 Orthogonal Array (OA) was used in Taguchi method to optimize the magnet width w and thickness t, and magnet position parameters i.e., D1, O1, and Rib. Using the D-optimal design criterion, 52 data points for five factors were selected for optimization of power factor and efficiency using response surface methodology to perform the sensitivity analysis. Regression model for efficiency and power factor are modeled using analysis of variance results. A 1.07 kW capacity PMSM was designed based on the optimized parameters and making use of efficient computational resource, i.e., RMxprt tool of the ANSYS Maxwell software and drive system in ANSYS Simplorer for real time results and performance study. The performance of PMSM in terms of line current, load torque, and efficiency has been verified with the experimental results and the efficiency data available in literature. The results were found to be in a good agreement. Confirmation test results showed that the Taguchi method is very successful in the optimization of permanent magnet synchronous motor dimensions.

The Heavy Elastica problem is a classical issue and has been addressed by many authors. The only analytical approach applied is the perturbative method, and the expansion through Taylor's series is the most recurrent technique. This transforms the nonlinear differential problem into a system of nonlinear (trigonometric) algebraic equations to compute the expansion coefficients. The main disadvantage is that the size of the obtained nonlinear systems is equal to the degree of the series expansion of the solution; therefore, to gain a good accuracy, it is necessary to manage the series expansion up to a considerable degree. Possibly for this reason, the use of perturbative techniques has gradually been abandoned and many authors have addressed the problem of Heavy Elastica with numerical methods. In this paper, a new analytical method based on the parabolic curvilinear abscissa mapping is presented. The result is that the problem of the Heavy Elastica takes on the same complexity as the well-known Elastica problem (concentrated forces and moment applied) and is therefore solved. The proposed method is compared with the Runge-Kutta integration approach and finite element results, showing the correctness of the solution suggested and its remarkable computational advantage. A further comparison is carried out by means of a number of experimental tests that agree with the analytical expected values. By expressing the proposed solution in a dimensionless form, Design Charts are given; they provide the results in the whole field of the domain, so that both kinematic and static variables can be deduced without computer aid.

Advances in thermal science force us to develop more efficient systems. The efficiency of widely-used gas turbine engines, is highly dependent on turbine inlet temperature. However, a high turbine inlet temperature yields material deterioration and long term degradation of turbines. To prevent material deterioration, cooling the hot zones of gas turbine engines, particularly turbine components and blades, is a priority. In this way, long term degradation of the turbine is prevented, while the thermal efficiency of the gas turbine engine is boosted. In the current paper, a flow field within a rib roughed blade internal cooling channel is discussed. Within this scope, a computational fluid dynamics analysis is conducted using a Standard k-ω turbulence model. After this, the same case is experimentally investigated. Experimental results obtained from particle image velocimetry measurements are used to validate the results of the computational fluid dynamics analysis. At the end of the study, the flow field is fully mapped with the recirculation and separation zones being clearly pinpointed.

PURPOSE Both safety and accuracy are of vital importance for surgical operation procedures. An efficient way to avoid the singularity of the surgical robot concerning safety issues is to maximize its manipulability in robot-assisted surgery. The goal of this work was to validate a dynamic neural network optimization method for manipulability optimization control of a 7-degree of freedom (DoF) robot in a surgical operation. METHODS Three different paths, a circle, a sinusoid and a spiral were chosen to simulate typical surgical tasks. The dynamic neural network-based manipulability optimization control was implemented on a 7-DoF robot manipulator. During the surgical operation procedures, the manipulability of the robot manipulator and the accuracy of the surgical operation are recorded for performance validation. RESULTS By comparison, the dynamic neural network-based manipulability optimization control achieved optimized manipulability but with a loss of the accuracy of trajectory tracking (the global error was 1 mm compare to the 0.5 mm error of non-optimized method). CONCLUSIONS The method validated in this work achieved optimized manipulability with a loss of error. Future works should be introduced to improve the accuracy of the surgical operation.

This paper presents the development (concept, design, detailing, and fabrication) and experimental validation of a novel low-damage precast concrete cladding panel system that can accommodate signi...

Infrared (IR) Thermography is currently a supplementary technique for breast cancer diagnosis. There have been studies using IR thermography and numerical modeling in an attempt to detect tumor inside the breast. Most of these studies focused on either the “forward modeling” problem or only used idealized or population-averaged patients’ data, whereas identification of the tumor inside the breast based on the thermal pattern is an “inverse modeling” problem dependent on personalized information of the patient. Inverse modeling is based on the idea that the surface thermal pattern of the breast can be used to determine the tumor features based on physical and physiological principles. The current study aims to develop a well-validated inverse thermal modeling framework that could be used to determine the depth and size of tumor inside a breast based on personalized patients’ breast data, such as thermogram and 3D geometry using efficient design optimization techniques and Finite Element Modeling (FEM) to support the process. The numerical modeling was validated by the experiments, conducted using artificial breasts. Results show that although DIRECT Optimization method can be employed to find the depth and size of the tumor with good accuracy, the technique can be very time consuming. On the other hand, Response Surface Optimization method is also able to find the depth and size of the tumor with less accuracy but faster when compared with DIRECT Optimization. The last method tested, Nelder-Mead method, failed to detect the tumor. The study concludes that Response Surface Optimization method should be used first, and after the range of parameters are found, the DIRECT optimization method can be applied for more accurate results. However the GA method was found to be the only viable and efficient design optimization method for reverse modeling when blood perfusion was adopted in the breast model and many parameters were searched for with patient specific data input for breast tumor diagnosis.

The use of social network theory and methods of analysis have been applied to different domains in recent years, including public health. The complete procedure for carrying out a social network analysis (SNA) is a time-consuming task that entails a series of steps in which the expert in social network analysis could make mistakes. This research presents a multi-domain knowledge model capable of automatically gathering data and carrying out different social network analyses in different domains, without errors and obtaining the same conclusions that an expert in SNA would obtain. The model is represented in an ontology called OntoSNAQA, which is made up of classes, properties and rules representing the domains of People, Questionnaires and Social Network Analysis. Besides the ontology itself, different rules are represented by SWRL and SPARQL queries. A Knowledge Based System was created using OntoSNAQA and applied to a real case study in order to show the advantages of the approach. Finally, the results of an SNA analysis obtained through the model were compared to those obtained from some of the most widely used SNA applications: UCINET, Pajek, Cytoscape and Gephi, to test and confirm the validity of the model.

This paper presents the modeling of a Proton Exchange Membrane Fuel Cell (PEMFC) implemented in PSCAD/EMTDC for steady and transient regimes applying equivalent electrical circuits. The model considers the activation, concentration and ohmic losses, dissipated as heat, of a PEMFC fuel cell, as well its thermodynamic behavior. In addition, this paper reviews the key concepts related to fuel cells, their operating mode and applications. Simulations are carried out under different load conditions to analyze the PEMFC model response, as well as series and parallel associations to increase the power supply. The results obtained from the model simulations are compared to experimental data retrieved from the literature.

There is a huge difference between electricity production and its demand. In order to meet the requirements, a selective power cut is carried out which is currently based on area and time. Although this is a simplistic solution, it has many drawbacks such as the area gets completely deprived of even the very basic appliances such as lights and fans, which do not contribute significantly to the power consumption. This creates a need to come up with a solution so that no one gets deprived of using basic appliances at any time and still be able to reduce power consumption to fulfill the ever-growing demand. This work has dealt with the same by implementing a device selective protocol which can selectively cut power of particular devices depending on their energy rating, power rating, manufacturer etc. by the use of power line carrier communication. Hence, revolutionizing the whole concept of area selective power cut to device selective power cut. Since, IoT refers to a network of devices or “Things”, this work incorporates the basic principles of IoT by essentially creating a network of devices which can communicate with each other, over low bandwidth.

Gimballed sensor system is a precision electromechanical assembly designed primarily to isolate the optical system from disturbances induced by the operating environment. This paper gives an insight to the design and development of gimballed sensor system for Line of Sight (LOS) stabilization of an electro-optical tracking and pointing system. Initially kinematic equations are formulated to establish a relationship between LOS angle and applied torque. This relationship is used to obtain nested loop transfer function model. First, the parameters of the proposed assembly are determined through experimentation & rigorous analysis process, and then conventional control design methodology is adopted for controller configuration design for current and rate loop. The frequency response analysis of the designed LOS stabilization model with conventional controller is done in simulation and the obtained results are verified experimentally against angular disturbances in real time scenario. Further, Based on prior qualitative information about system dynamics and linguistic performance criteria, a fuzzy logic controller of mamdani type with simplified rule set is developed with an objective to improve the disturbance attenuation and command response performance of designed system irrespective of angular disturbances due to platform vibrations, model uncertainties and mass imbalance in gimbal assembly. Both the Fuzzy logic simulation model and conventional model are tested based on critical performance characteristics such as stability of the loop, responsiveness of the loop and insensitivity to disturbances. Finally, the comparative analysis suggests that, although both the control configuration satisfies the required accuracy, Fuzzy logic control certainly improvised the performance of the gimballed sensor system and hence can be very effective for more precise pointing, tracking and stabilization application.

Wire electrical discharge hybrid turning (WEDHT) is one of the unconventional machining process following thermo-electric material removal principle to machine cylindrical components at meso and micro scale with very high accuracy and precision. Thermal simulation and validation of Ti6Al4V alloy on temperature profile, crater formation, rate of material removal during WEDHT process was reported less by previous researchers and this creates path for framing the objective. The objective of the present study is to, numerically simulate and validate the material removal through crater formation and temperature generation in WEDHT process using COMSOL Multiphysics 5.2. The time-dependent and heat transfer in solid module is chosen with current, voltage and discharge ON time (TON) of 106, 109, 112 µs as the input parameters for modelling. With the same varying TON, varying wire feed rate of 3, 4, 5 m/min and varying servo feed of 5, 7, 9 mm/min, the validation experiments are performed to validate the crater formed. Based on the comparison plot, the numerically predicted and experimentally obtained data resulted in the error percentage of 41.6%, 21.2%, 15% for 106, 109 and 112 µs discharge ON time, respectively. The images of the crater formed on the work material are captured using scanning electron microscope and atomic force microscopy images. The results of the numerical and experimental study, proved that, high the TON, more would be material removal.

A functional vascular network is essential to the correct wound healing. In sprouting angiogenesis, vascular endothelial growth factor (VEGF) regulates the formation of new capillaries from pre-existing vessels. This is a very complex process and mathematical formulation permits to study angiogenesis using less time-consuming, reproducible and cheaper methodologies. This study aimed to mimic the chemoattractant effect of VEGF in stimulating sprouting angiogenesis. We developed a numerical model in which endothelial cells migrate according to a diffusion-reaction equation for VEGF. A chick chorioallantoic membrane (CAM) bioassay was used to obtain some important parameters to implement in the model and also to validate the numerical results. We verified that endothelial cells migrate following the highest VEGF concentration. We compared the parameters—total branching number, total vessel length and branching angle—that were obtained in the in silico and the in vivo methodologies and similar results were achieved (p-value smaller than 0.5; n = 6). For the difference between the total capillary volume fractions assessed using both methodologies values smaller than 15% were obtained. In this study we simulated, for the first time, the capillary network obtained during the CAM assay with a realistic morphology and structure.

The mechanical behaviour of a high performance polycaprolactone based polyurethane elastomer (PCL) up to large strain levels, cyclic loading and equibiaxial stress has been assessed. The PCL can be categorised as a rubber-like material, thus, showing nonlinear stress-strain behaviour. The materials elastic network is based on a high molecular weight PCL polyol which gives the material its elastomeric behaviour similar to polyurethanes. In this work, mechanical testing capturing the major features of the stress-strain curve under different loading conditions is performed. Both, uni-axial loading-unloading curves and bulge test are thoroughly studied through the addition of digital image correlation (DIC) to measure the strain field. Results show the presence of hysteresis and loading configuration dependence. Then, two well-known hyperelastic constitutive models, the Arruda-Boyce eight-chain and Bergström-Boyce, were fitted to the uni-axial monotonic and cyclic test data and compared to the bulge test experimental results through finite element analysis (FEA) in Abaqus.

A new geometry of roughness in the sinusoidal form has been investigated computationally using Computational Fluid Dynamics (CFD) software for examining the influence of roughness on heat transfer ...

In an indoor environment, many factors may affect the airflow characteristics and thermal comfort. Hence, a lot of research has been carried out in order to investigate the impact of these factors....

Both theoretical study, experimental validation, and outdoor performance assessment of a single grid-connected photovoltaic plant installed on the roof of the car parking located in Renewable Energ...

In this study, the sensitivities of weave and capsize speeds with respect to design parameters were calculated on the basis of the linear forms of uncontrolled-bicycle dynamic equations. The significance of the design parameters and the way in which the stable speed range is changed were determined by analyzing the sensitivity curves. Among the seven important parameters (out of 25), head angle was found to be the most dominant, followed by the diameter of front wheel, mass, and moment of inertia, demonstrating the importance of front side design to bicycle stability. The procedure for predicting the stable speed range using sensitivity information was also investigated. When a single parameter was changed, the stable range was determined by that parameter, whereas when multiple parameters were changed, the stable range was determined by summing all the contributions from each parameter. The weave speeds in the nominal and changed configurations yielding the lowest values were measured using an experimental bicycle of variable configuration. A comparison of the measured and predicted values of weave speeds showed a good correlation, demonstrating the validity of the sensitivity-based stability analysis. This study used a novel procedure for predicting the stable speed range through the sensitivity analysis of design parameters related to bicycle stability and validation of the stable speed range with experiment.