bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of the Residual Stress Distribution in the 3D-Stacked Electronic Modules by Embedded Strain Sensors
Authors: Mizuno Ryota , Nakauchi Genta , Suzuki Ken , Miura Hideo
Published: January 2020

In this study, micro-scale strain sensors were embedded in a silicon chip to measure the variation of the local stress distribution around thin film interconnections used for 3D semiconductor modules. Piezoresistive effect of single crystal silicon was applied to the sensors. The stress sensitivity at room temperature was 1.3 MPa/Ω. Even though the stress sensitivity varied as a strong function of temperature, it was confirmed that this sensor can measure the stress distribution quantitatively in the temperature range from room temperature to 80°C at most. And the variation of the residual stress in electroplated copper thin films during heat treatment was investigated from the viewpoint of the change of stress amplitude during a thermal cycle. From the obtained results, it was confirmed that the recrystallization occurred when the films were annealed at only 200°C, and the change of the micro textue of the films caused the change of their residual stress. Therefore, it is very important to control the micro texture during electroplating for assuring long term reliability of interconnections.
Effect of Coating Process Parameters on the Development of Residual Stresses in Ceramic Coatings
Authors: Gadelmoula Ali , Al-Athel Khaled
Published: January 2020

Ceramic coatings are widely used in many engineering applications, especially applications related to components operating at elevated temperatures. One of the main issues relates to ceramic coatings is the development of residual stresses due to quenching and the thermal mismatch between the deposited coating layers and the substrate. In this work, a computational framework is developed to investigate the effect of various process parameters on the development of the residual stresses. The geometry of the coating layers and the interface roughness between the layers is first generated using SimCoat, a Monte Carlo based statistical algorithm that determines the effect of process parameters (droplet size, spraying speed, etc.) on the characteristics of the developed coating (coating thickness, porosity, etc.). An in-house code is used to convert the statistical data into a finite element (FE) model. Various FE models are generated with different process parameters, and the development of residual stresses is compared between them. The developed framework can be used by material scientists and engineers to predict the quality of the coating and optimize the process parameters to any specific application.
Neural Network Inverse Based Omnidirectional Rotation Decoupling Control to the Electrodynamic Reaction Sphere
Authors: Huai Zhouyu , Zhang Ming , Zhu Yu , Chen Anlin , Li Xin , Wang Leijie
Published: January 2020

The electrodynamic reaction sphere is a novel actuator for the spacecraft attitude control subsystem. This paper proposes a neural network inverse based decoupling control scheme to actualize the omnidirectional rotation of the electrodynamic reaction sphere which has strong multivariable nonlinear coupling features due to the induction-based drive. And an integrated electromagnetic torque model of the reaction sphere is firstly derived from the electromagnetic field analysis and modified with the finite element analysis method. Then based on the integrated torque model, a back propagation feedforward neural network is constructed and trained to approach the inverse dynamics which transforms the original system into a pseudo-linear system. Furthermore, an additional PI controller is introduced to achieve good control performance against the unmodelled dynamics. Finally, the effectiveness of the proposed method is validated by simulations.
A Computer Vision Based Automated Polarity Testing System of Rocket Motor Nozzle
Authors: Wang Guan , Yi Hang , Zhou Dengji
Published: January 2020

Launch vehicle realizes pitch, yaw and roll control through the swing of motor nozzles. Current rocket motor polarity test relies on simultaneous close observation of multiple nozzles by trained testers which thereby is both time-consuming and low-automation. And it is difficult for the human eye to recognize and track the working condition with a small amount of fast swing. By installing a set of cameras and designing a measurement system based on computer vision method, the oscillation trajectory and polarity of each nozzle can be effectively judged. We show that our system is able to improve test efficiency as well as test coverage, make testing process traceable and ensure measurement reliability.
Design of Metallic Support for Electronic Devices Installed on the Interstage 2/3 of Vega-C Launcher
Authors: Di Caprio F. , Cristillo D. , Giusto G. , Zallo A.
Published: January 2020

The purpose of this paper is to provide a numerical procedure developed to obtain the best design (in terms of weight and requirement fulfillment) for a structural component subjected to a launcher environment. The component analyzed represents the support used to mount the SAD/S and DBAT equipment into the VEGA C launcher Interstage 2/3. The final design is obtained by means of an optimization process which aims to satisfy the environmental requirements prescribed by the Vega General Specifications. The developed procedure is based on generation of a fully parametric FE model that is able to switch between ANSYS and NASTRAN software. This routine allows us to execute a topometry optimization with Nastran (by using a 2D model) and to generate a full 3D model (which represents the best compromise among structural performance, manufacturing cost and weight) with Ansys. The final design shows a weight reduction about 50% with respect to the initial provided model.
An Optimized 3D Probe Using Sensitivity and Compliance Analysis
Authors: Zheng Weikang , Liu Zhigang , Guo Junkang
Published: January 2020

High-precision micro/nano probe plays an increasingly important role in manufacturing and measurement. The multi-arm elastic mechanism that can produce deformation under the contact force is widely used in the design of probe. The striking feature of this mechanism is that multiple variables are coupled to each other and are not easily separated. However, the transfer matrix of probe, rather than a multivariable decoupling model, is widely used as a measurement model in traditional research. Transfer matrix appears as a “black box” and does not reveal working principles of probe. Our previous research proposed a 3D decoupling model. The 3D model presents the coupling relationship between input and output variables, and also finishes a theoretical explanation of complex features of 3D probe. Recent studies have found that this decoupling model has practical value in parameter and shape optimization of probe. As the optimized purpose, two indicators — sensitivity and compliance (reciprocal of stiffness) are proposed from the model. The increased sensitivity means the probe has a lower resolution requirement for the capacitive sensor used. High compliance of probe means small contact force between the stylus ball and workpiece. Excessive stiffness can cause excessive contact forces that damages surface of workpiece. Combined with theoretical model and finite element analysis (FEA), the key parameters affecting sensitivity and compliance of probe are extracted, and a new optimized elastic mechanism based on an original Hexflex mechanism. The new optimized probe has better performance with sensitivity, input compliance, output compliance increased by 78.6%, 48.4%, 157.7%, respectively.
Telemetry Data Prediction of Launch Vehicle Attitude Control Engine Using LSTM
Authors: Yi Hang , Wang Guan , Geng Hui , Xu Hao , Wang Wei , Zhou Dengji
Published: January 2020

The attitude control engine used by the launch vehicle is mainly composed of a pressurized gas cylinder, a pressure reducer, a tank, a duct, a pitch extension, a roll extension, a yaw extension, and a sinker extension. In this paper, a long short-term memory network is used to train the telemetry data transmitted from the temperature and pressure sensor points distributed in various positions of the attitude control engine, such that the state of the rocket attitude control engine can be deduced and predicted in real time through the data-driven digital twinning system. It is possible to detect potential data anomalies in advance and locate the faults, so that the control system can change the attitude control strategy in sufficient time to alleviate the fuel loss issue as well as positional deviation caused by minor faults, so as to better ensure the success of the mission.
Influence of Precipitation and Dislocation Density on Flow Stress Characteristics Under Compression Deformation of Heat-Treated 17-4 PH Stainless Steel Alloy
Authors: Sathyanath Athul , Meena Anil
Published: January 2020

The strengthening mechanism of 17-4 PH stainless steel is mainly due to the precipitation of copper particles in the martensitic lath matrix. The renowned steel grade possesses an exceptional combination of high strength and excellent corrosion resistance and hence is widely employed in high stress environments. In that case, under external loading, the movement and accumulation of dislocations are influenced by the nature of precipitation. Hence, the present study is based on the impact of precipitation on the dislocation induced hardening during compression of the heat-treated 17-4 PH stainless steel. Room temperature uniaxial compression test was used to evaluate the direct effect of precipitates and the dislocation interaction on the flow stress and strain-hardening behavior under the different heat-treated regime. Microstructural evolution during deformation and its influence on the strain-hardening mechanism were analyzed by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). A semi-empirical model was adopted to quantify the role of precipitate nature on the strain-hardening rate. The evaluated normalized microstrain and dislocation density from the XRD analyses were used to explain the observed variation in the mechanical property. Coarse particle precipitation was found to greatly affect the strain-hardening behavior of the steel alloy during compression deformation.
Weld Bead Performance Assessment of P-GMAW Using Acoustic Emission (AE) Signals Through NDT Methods for MS ASTM A 106 B Grade Material
Authors: Addamani Rudreshi , Venkatadasu Ravindra Holalu
Published: January 2020

Pulsed Gas Metal Arc Welding (P-GMAW) process is used in many industries to gain high quality, productivity and cost effective products in fabrication of welded joints. The input process parameters will affect the quality, productivity and cost of the welding and are considered to be the most important factors. P-GMAW is an excellent alternative to constant voltage GMAW process for those industries which are looking to boost efficiencies since the process helps to improve quality of welds over varying operator’s skills. The process enables low mean current and low net heat input with stable spray transfer. To produce a very precise control of the arc, P-GMAW applies waveform control logic through a broad wire feed and speed range. In order to understand and control the P-GMAW welding process, it is necessary to determine the input and output relationship parameters. The process is modified spray transfer in which the power source switches between low background current or voltage and a high peak current or voltage between 30 to 400 times per second. Over this period, the peak current pinches off droplets of wire and drive it to the welded joints. By the mean time, background current maintains the arc but produces low heat input that metal transfer cannot occur allowing weld pool to solidify. The process enables low mean current and low net heat input with stable spray transfer. The objective of the present study is to assess the weld bead performance and joint strength by carrying out the destructive testing using AE signals. Experiments have been conducted on MS ASTM A 106 material using 1.2 mm copper coated filler wire based on the Taguchi’s L27 standard orthogonal array. Input parameters considered to carry out the experiments are current, gas flow rate and wire feed rate with a constant speed. The direct response parameters are Ultimate Tensile Strength (UTS, N/mm2), Yield strength (YS, N/mm2) and % of elongation. Indirect response parameters signals are Viz., Acoustic Emission (AE) signals such as welding AERMS, welding AEENERGY, tensile AERMS and tensile AEENERGY are considered to assess the performance of the weld bead joint. From the obtained results, it is clearly observed that a good relationship exists between welding AERMS welding AEENERGY with tensile AERMS and tensile AEENERGY to evaluate the performance of the weld bead joint. The results are validated through carrying out different NDT testing methods on weld bead joint Viz., macro test examination, X–radiography, scanning electron microscope images to analyse external and internal defects in the welded joints. EDX investigation is performed for elemental composition on welded joint in different zones.
Heat Transfer Characteristics of a Train of Droplets Impinging Over a Hot Surface: From Film Evaporation to Leidenfrost Point
Authors: Guggilla Ganesh , Pattamatta Arvind , Narayanaswamy Ramesh
Published: January 2020

Due to the advancements in computing services such as machine learning and artificial intelligence, high-performance computing systems are needed. Consequently, the increase in electron chip density results in high heat fluxes and required sufficient thermal management to maintain the servers. In recent times, the liquid cooling techniques become prominent over air cooling as it has significant advantages. Spray cooling is one such efficient cooling process which can be implemented in electronics cooling. To enhance the knowledge of the process, detailed studies of fundamental mechanisms involved in spray cooling such as single droplet and multiple droplet interactions are required. The present work focuses on the study of a train of droplets impinging over a heated surface using FC-72 liquid. The surface temperature is chosen as a parameter, and the Dynamic Leidenfrost point (DLP) for the present impact conditions is identified. Spread hydrodynamics and heat transfer characteristics of these consecutively impinging droplets till the Leidenfrost temperature, are studied and compared.
Design Process Deconstructed: The Industry Case of an Elevator Button Assembly Redesigned for Additive Manufacturing
Authors: Puttonen Tuomas
Published: January 2020

Additive manufacturing (AM) has during the 21st century gradually shifted from prototyping towards the manufacture of end-use quality parts. The drivers to utilize AM instead of conventional manufacturing methods are often linked to geometrical design freedom, increased performance, customization, part consolidation, and weight reduction. However, designers have struggled to take full advantage of these new capabilities. In part, this is due to a pervasive engineering mindset locked into the constraints of conventional manufacturing technologies. Another reason is the lack of efficient design methodologies that would take into account the new capabilities of AM.

In this paper, to address the latter deficiency, an assembly redesign process for AM is deconstructed and analyzed. The studied assembly is an elevator accessibility button, which is a high-mix low-volume product. From the industry perspective, AM could reduce costs and increase the agility of production. Through systematic requirements mapping, part- and product-level functional analysis, a holistic functional analysis of the product is composed. The results of the product functional analysis are illustrated in a visual 3D design space. The 3D illustration is suggested as a conceptualization tool for the designers and as a way to reinforce creativity in the design process. The usability and expandability of the tool are discussed and contrasted with the current design methodologies for AM.
Decontamination of Heavy Metals From Municipal Sewage Sludge (MSS) by Electrokinetic Remediation
Authors: Ribeiro A. , Araújo J. , Mota A. , Campos R. , Vilarinho C. , Carvalho J.
Published: January 2020

A large quantity of sludges resulting from the treatment of MWWTP (Municipal Wastewater Treatment Plant) effluent is generated annually following the increase of population density and acceleration of urbanization. Sludge production in Europe has been predicted by around 12 million tons in 2020. As a solid waste, appropriate disposal of Municipal Sewage Sludge (MSS) has been taken seriously due to its larger volume and toxic substances such as heavy metals.

Electrokinetic remediation has more advantages in heavy metals uptake compared to other technologies, due to the ability to treat soils in-situ and to remove heavy metals from soils. In this work, it was studied the remediation of MSS by the electrokinetic remediation coupled with activated carbon (AC) as a permeable reactive barrier (PRB). It was applied an electric current of 3 V cm−1 and it was used an AC/sludge ratio of 30 g kg−1 of contaminated sludge for the preparation of the PRB. In each trial, the evolution of cadmium (Cd), lead (Pb), copper (Cu), chromium (Cr), nickel (Ni) and zinc (Zn) removal from the sludge were evaluated.

Results proved that this process is perfectly suited for the removal of chromium, nickel and zinc metals from the sludge. At the end of the operation time, it was achieved a maximum removal rate of 56% for chromium, 73% for nickel and 99% for zinc, with initial concentrations of 2790 mg kg−1, 2840 mg kg−1, and 94200 mg kg−1, respectively.

Based on these results, it was proved the technical viability of the proposed technology (electrokinetic with AC as a permeable reactive barrier) to treat municipal sewage sludges.
A Knowledge-Based Engineering Workbench for Automated Tolerance Specification
Authors: Sauer Christopher , Heling Bjoern , Schmutzler Simon , Schleich Benjamin
Published: January 2020

Designers often lack important information about achievable manufacturing tolerances. Moreover tolerances are not considered from the beginning of product development. This often leads to inaccurately specified parts. Furthermore the full potential of the manufacturing departements is not used.

This contribution tackles those areas by presenting a knowledge-based engineering workbench for automated tolerance specification, which has also been implemented using a commercial CAD system. This tool allows the designer to assign part tolerances that take into account the achievable accuracies for a specific manufacturing process, while at the same time allowing for specific part properties. The novelty of the presented approach can be found in the knowledge-based support of the product developers in tolerance specification by employing an engineering workbench. Moreover preprocessing for variation simulation and analysis is supported. It is possible to automate parts of the tolerance specification process, using the presented approach.
Simulation Model Uncertainty Quantification and Model Calibration for Natural Gas Compressor Units
Authors: Wei Tingting , Zhou Dengji , Yao Qinbo , Zhang Huisheng , Lu Zhenhua
Published: January 2020

Natural gas compressor units, as the core equipment in natural gas transportations, play a crucial role in daily industrial production. Meanwhile, with the increase of equipment operating time, the performance of each component will inevitably decline and even fail in severe cases. Apparently, the unit simulation model, also known as the mechanism model with the characteristic maps, lays foundation for remotely monitoring the conditions of this rotating machine and giving the suggestions for equipment maintenance. And it should be accurate and adaptive according to the performance degradation. To achieve this goal, some thermodynamic parameters and their data samples are decided to represent this model with the Grey Relational Analysis and the optimal Latin Hypercube Sampling. Then, a data-driven model based on Gaussian process is established and the Bayesian calibration method is applied to obtain the model uncertainty, which means the degradation uncertainty in this study. This approach can realize the uncertainty quantification and the result can be adopted to judge and correct the characteristic map in the simulation model. A case study is implemented on an industrial compressor unit to demonstrate this method’s effectiveness. The corrected model outputs are compared with the actual data to acquire the model accuracy and their variance is 0.993, which points out their similarities. This approach avoids the disadvantages of the traditional model correction methods such as low utilization rate of operational data, non-use of prior information, and long fitting time. It makes full use of prior information and numerous data. Besides, it can reduce the diagnostic error, provide new possibility for the real-time monitor and promote the development of health management in the industrial equipment.
Numerical Determination of Unconstrained Area Effect on Springback in Incremental Forming of 5052-H32 Aluminum
Authors: Grimm Tyler J. , Mears Laine
Published: January 2020

Incremental forming (IF) is a novel sheet material forming process which promises significant energy savings within the low and medium volume sheet production industries. This advantage stems from IF’s dieless forming nature, which alleviates the need for time and energy input towards die fabrication and offers significantly greater flexibility. However, a distinct disadvantage of this process is its relatively low forming rate compared to conventional stamping, which reduces its feasibility of use in higher volume productions.

Springback is one disadvantage of incremental forming which has hindered its implementation within industry. Spring-back reduction methods, as well as springback characterization, can be found throughout literature. However, very few publications disclose the clamping dimensions used for fixturing work-pieces. This study numerically determines the springback effect of utilizing various clamping structures and presents an empirical solution for determining the springback of truncated pyramid geometries for various constraining areas. The resulting equation was found to have an acceptable degree of error relative to experimental analysis.
Natural Convection in Yield Stress Fluids From a Confined Horizontal Plate
Authors: Patel S. A. , Raja A. H. , Chhabra R. P.
Published: January 2020

The heat transfer characteristics from an isothermal heated plate in a quiescent yield stress fluid in a cavity was investigated over a wide range of parameters (Rayleigh number, 102 ≤ Ra ≤ 105, Prandtl number, 10 ≤ Pr ≤ 100, and Bingham number, Bn ≥ 0) where the flow is known to be laminar and steady. The coupled momentum and energy equations have solved here numerically within the framework of Boussinesq approximation to capture the temperature-dependent fluid density. The results demonstrate that for a given value of the Rayleigh number, there exists a critical value of the Bingham number, above which the fluid is completely unyielded and heat transfer occurs solely by conduction. In order to delineate the effect of domain geometry on the conduction limit, the study was extended over a range of geometrical aspects by varying the aspect ratio (λ = diameter of the cavity/ a length of the plate), 2 ≤ λ ≤ 5. This work shows that the critical value of the Bingham number can be described as a function of geometry of domain, Ra and Pr. The value of critical Bingham number increases with the increasing aspect ratio and Rayleigh number in order to approach the conduction limit. The yield surfaces show that the increasing values of Rayleigh number induce fluid-like behaviour whereas Bingham number opposes this propensity. The average Nusselt number decreases with the increasing Bingham number due to the suppression of the advective component of heat transfer.
Simultaneous and Iterative Estimation of Vehicle Ride Model States and Parameters
Authors: Sampathraghavan Lakshmi , Ramarathnam Krishnakumar
Published: January 2020

With advancements in vehicle electronics and growing focus on vehicle safety systems, state and parameter estimation has become a remarkable sphere of research. In this study, the vehicle vertical dynamics states and parameters were estimated simultaneously and iteratively with relevant vehicle responses. This was achieved through vehicle tests, designed to excite the corresponding vehicle states. A linear Kalman filter was used for state estimation. Vehicle parameters were obtained as a optimal solution using an optimization algorithm. With the help of multi-DOF vehicle ride model along with real vehicle measurements, the state and parameter estimators work concurrently to obtain the results. A cleat test was performed for a Sports Utility Vehicle (SUV) in IPG CarMaker® and in reality, for evaluation of the proposed framework. The state estimation results showed upto 93% correlation from simulated data and upto 81% correlation from real time measurements. Parameter estimation produced an average error of only 9.1%. This demonstrated the efficacy of the algorithm for use in vehicle systems.
Polychromatic Coloring of Dental Zirconia by Inkjet Printing
Authors: Rehekampff Christoph , Rumschöttel Dominik , Irlinger Franz , Lueth Tim C.
Published: January 2020

To enable the development of an automated coloring process, dental zirconia is examined in terms of porosity, pore size and shrinkage during sintering. The properties of commercially available metal ionic inks such as viscosity, density and surface tension are investigated. Droplet impact on the zirconia surface and the absorption into the pores is analyzed with a high speed camera. The color result after sintering is investigated and compared to tooth samples.

A method is developed to achieve a realistic, smooth color transition on flat zirconia samples. This is achieved by mixing the single inks directly on the zirconia through sequential application. Consequently, the number of different inks required to reproduce the full dental color scale can be reduced. Additionally, three dimensional tooth replacements are colored with the developed method.
Maximizing Energy Harvesting of Photovoltaic Panel Full Tracking Optimization
Authors: Abdelmaksoud Ahmed Y. , A. Hegazi Hesham , El Morsi Mohamed S. , Metwalli Sayed M.
Published: January 2020

The wide spread use of solar energy and photovoltaic solar cells attracts researchers to work hard for the objective of improving their performance to be a viable attractive alternative to fossil fuels. This work presents the optimization of the output power of a photovoltaic solar cell to harvest maximum power. The power is optimized based on PVP full tracking of the sun and the effect of the tilt, the azimuth, and the incidence angles on its performance. A meta-model is utilized as a tool in the optimization technique. A case study which develops 2nd, 3rd, and 4th order hyper-surface equations that depend on day and hour to get the optimum tilt angle and optimum azimuth angle for the city of Hurghada in Egypt. The power produced from the polynomial meta-model algorithm is higher by 25.5% over the fixed tilt and azimuth angles. The developed equations from the meta-model optimization technique can be used in tracking control systems to get optimum tilt and optimum azimuth angles at any hour and at any day. By comparing the metamodel and the lengthy performance optimization technique, the error is around 1.1%. Comparison has also been made between the cost of the fixed and full tracking photovoltaic systems.
A New Mobile Anti-Ramming System
Authors: Baragetti Sergio , Arcieri Emanuele Vincenzo
Published: January 2020

The recent vehicle-ramming terror attacks in Berlin, Barcelona, London and Nice pointed out our vulnerability: all of us could be victims during a walk in our squares or in crowded places, it is sufficient a car, a van or a truck.

The current solution to this problem is the application of concrete barriers in our cities. These devices are not good-looking and give a sense of danger to the human beings. But are they effective?

Starting from this question, the authors studied the effectiveness of these barriers and developed a new good-looking mobile device.

The study was carried out by means of mathematical and numerical models. In particular, a spring-mass system was used in order to macroscopically represent the problem and finite element analyses by explicit calculation in Abaqus were carried out. Also Smoothed Particle Hydrodynamics (SPH) method was used in the numerical models.

The final shape of the barrier is a planter full of water which is urban furniture and anti-ramming system at the same time. The barrier is made of metal, without foundation and characterized by high friction coefficient between the ground and the barrier itself and a good mass distribution, studied to stop the vehicle in few meters.

The high deformability and the ability of the water in the barrier to take away a lot of energy allow to stop a 3500 kg vehicle running at 64 km/h and the system itself in less than four meters as demonstrated by the crash test carried out. As consequence of this crash test, the anti-ramming system is IWA 14-1:2013 and PAS 68:2013 certificated.
Membrane Fouling Mitigation in Water Filtration Using Piezoelectrics
Authors: Aronu Obinna , Abramowitz Harvey , Nnanna Agbai George
Published: January 2020

The clogging of filtration membrane by particles otherwise known as fouling is a major concern in membrane filtration technology due to severe flux reduction associated with it, which results to the reduction of membrane lifespan, reduced system performance and increased process and operating costs in industries that utilize membrane in their production process. This is because the cleaning or replacement of the fouled membrane requires production to be interrupted for the cleaning process or the entire system to be shut down for the replacement process to take place, leading to great loses to the industries involved. Many approaches have been devised over the years through research to tackle this problem, some of which not only undermine the performance of the filtration membrane but also contribute to great loses to industries that apply them. Cheaper and more efficient means of fouling control remains the key to salvaging this problem. This work proposes a water filtration system in which piezoelectric crystals attached at strategic points on a tubular polyvinylidene fluoride (PVDF) membrane are used to increase flux and delay the clogging of the pores of the filtration membrane by particles during water filtration. Filtration tests with mud solution show that the membrane vibrated with piezoelectrics reduced the clogging of the pores and increased permeate flux of the filtration process as compared with the case where the membrane was not vibrated with piezoelectrics, suggesting that vibrating the system with piezoelectrics is a good fouling reduction method that can be used in fluid separation processes. To optimize the permeate flux production of the system and fouling reduction, the anti-fouling effects of the piezoelectric crystals on the membrane surface is investigated through experiments together with the effects of voltage application, positioning and placement distance of the piezoelectrics and some other variables involved in this work.
An Application of a Digital Twin to Robotic System Design for an Unstructured Environment
Authors: Marshall Matthew Q. , Redovian Cameron
Published: January 2020

An experimentable digital twin is created to aid in a design decision (beginning of life stage) for a robotic system. This product is meant to automate a material-feed system. The robot comprises a six-axis manipulator mounted on a mobile base. Due to variability in the dimensions of the material-feed system and positioning error of the mobile base, the material-placement routine is considered to take place in an unstructured environment. Working therein requires exteroceptive sensors, in this instance taking the form of computer vision. Data from this subsystem are used to match the geometry of the digital twin to the physical environment. This close correspondence between physical and virtual embodiments allows for significant design decisions to be reached from simulated experiments. In this case, two motion-planning approaches are compared and it is determined that the costs associated with implementing the dynamic one in the lab for testing are merited by its ease of use and reliability, since simulation-based control employs all current information.
Low Frequency Absorption of Additively Manufactured Cylinders
Authors: Kaye Sophie R. , Casavant Ethan D. , Slaboch Paul E.
Published: January 2020

Attenuating low frequencies is often problematic, due to the large space required for common absorptive materials to mitigate such noise. However, natural hollow reeds are known to effectively attenuate low frequencies while occupying relatively little space compared to traditional absorptive materials. This paper discusses the effect of varied outer diameter, and outer spacing on the 200–1600 Hz acoustic absorption of additively manufactured arrays of hollow cylinders. Samples were tested in a 10 cm diameter normal incidence impedance tube such that cylinder length was oriented perpendicular to the incoming plane wave. By varying only one geometric element of each array, the absorption due to any particular parameter can be assessed individually. The tests confirmed the hypothesis that minimizing cylinder spacing and maximizing cylinder diameter resulted in increased overall absorption and produced more focused absorption peaks at specific low frequencies. Wider cylinder spacing produced a broader absorptive frequency range, despite shifting upward in frequency. Thus, manipulating these variables can specifically target absorption for low frequency noise that would otherwise disturb listeners.
Fully Transient Model of a Hydraulic Accumulator
Authors: Kratschun Filipp , Rambaks Andris , Schmitz Katharina
Published: January 2020

Hydraulic piston accumulators play a major role especially within the field of stationary hydraulics. The calculation of the amount of hydraulic energy which can be stored in such an accumulator is crucial when it comes to a precise system design. The knowledge of the temperature within the accumulator is required in order to calculate the amount of energy to be stored.

This paper presents a simulation approach with the goal to simulate the gaseous phase within a piston accumulator and to present results for the polytropic exponent without conducting costly experiments. The temperature, pressure, density and velocity profiles inside of the gaseous phase as well as the temperature profile inside the boundaries are calculated transiently in order to achieve that goal.

The effects of dissipation, heat transfer and transient wall temperature are added to the simulation routine continuously and their effects on the results are discussed in detail.
Pressure Drop in Circular Two-Phase Pipe Flow As Influenced by the Angle of Inclination
Authors: Worl Bethany , Nielson Samuel , Wang Xiuling
Published: January 2020

A variety of models exist to describe the frictional pressure drop for two-phase flow in a pipe. These models all are based on assumptions and simplifications of the flow regime and can experience difficulty when modeling flow through non-horizontal pipes due to the buoyant effects as the bubbles grow in size. Using computational fluid dynamics, it is possible to model the interaction between the two phases and determine an expected pressure drop. In order to evaluate the effect of the inclination angle of a channel, a parametric study will be conducted using ANSYS Fluent; these predicted pressure drops will then be compared to those found in literature for validation and then to other theoretical pressure drop calculations. Through this study, the benefits of both the theoretical framework and the numerical simulation will be identified.
Exergy Analyses of a Solar-Biogas Hybrid Micro Gas Turbine for Power Generation
Authors: Alshahrani Saad , Engeda Abraham
Published: January 2020

Solar thermal power is considered one of the most promising renewable energy resources that has witnessed a great technological improvement in the last two decades. Saudi Arabia has very intensive solar radiation because it is located in the sun belt region, which has led it to become one of the largest solar energy producers. In this paper, detailed exergy analysis of a solar-biogas hybrid micro gas turbine for power generation is presented. The system is driven by a central receiver and biogas as backup based on the hybridization technique. The net power output of the system is set to 100 kW. This study demonstrates that the highest exergy destruction occurs in the recuperatore and ceramic heat exchanger, about 22.6% and 22.5%, respectively, and that is due to the high entropy generation and the irreversibilities in these components. Moreover, the exergy destruction for all system components was examined at different environment temperatures. The study revealed that the exergy destruction for compressor, regenerator, and receiver decreases with an increase in the environment temperature, but the exergy destruction increases for turbine and heliostats field.
Heat Transfer Induced by Electron Tunneling Between Two Metal Plates
Authors: Yao Bojing , Pan Liang
Published: January 2020

We calculated the heat transfer caused by electron tunneling between two semi-infinite metal plates separated by a vacuum gap, which are made of the same material. The tunneling of electron is described by one dimensional quantum tunneling and its transmission coefficient. Sommerfeld model is used to derive the math expression of electron motion. Based on calculation results, we find that when the gap distance is below 1 nm, electron tunneling induced heat transfer starts to be considerable, which could exceed near-filed radiative heat transfer.
Acoustic Control of a Maneuverable Marine Hydrokinetic Cycloturbine
Authors: Goldschmidt Margalit Z. , Jonson Michael L. , Horn Joseph F.
Published: January 2020

Marine Hydrokinetic (MHK) cycloturbines exploit tidal currents to generate sustainable electric power. Because of the harsh marine environment, MHK cycloturbines require frequent maintenance and repair, which for current systems necessitates the use of a ship, making the process difficult and costly. A novel MHK cycloturbine system has been designed that uses pitching foils for maneuver, potentially circumventing the costs and difficulties associated with deployment and repairs. The vehicle fatigue is decreased and the vehicle’s acoustic signature underwater is reduced by design of a novel acoustic controller. This controller specifically reduces the tonal noise at blade rate frequency.

Each turbine foil radiates noise equivalent to an acoustic dipole at multiples of blade rate frequency, and so the vehicle is modelled as an acoustic multipole. At blade rate frequency, the turbine size compared to its acoustic wavelength allows for the entire vehicle to be treated as a compact source. The effect of turbine clocking on directivity and sound power is shown. The effects of the designed controller to reduce tonal noise at blade rate frequency and multiples are verified experimentally through testing in ARL’s Reverberant Tank facility. Fixing a Subscale Demonstrator (SSD) to a reaction frame provides the ability to measure the integrated loads using load cells. The radiated sound pressure is computed for the load cell data obtained. Acoustic control is implemented using the turbine RPM: turbines are clocked by slowing one turbine relative to another for a short period of time.
Computational Model for Knowledge Transfer Skills in Industry 4.0 in an Enhanced and Effective Way
Authors: Artifice Andreia , Luis-Ferreira Fernando , Sarraipa João , Jardim-Goncalves Ricardo
Published: January 2020

The current swift pace of development is a reality that is crossing many domains in society demanding specific measures to cope with such scale of development. In the new paradigm of Industry 4.0, new competences and professional skills are needed in the most diverse quadrants of society. The importance of adequately adapt the societal systems and to promote the adequate skills is worth as much as the value we give to present and future generations. Among demanding challenges arising from this changing reality, the transfer of knowledge from academia to industry is probably the most demanding. This reality is present across diverse countries and continents and for that, pilot deployments and lessons learned should be documented and shared to promote better and effective skill development. In this context, the SHYFTE project is establishing a computational model for knowledge transfer skills in industry 4.0.
A Biomass Supply Chain Optimization Framework With Linear Approximation of Biomass Yield Distributions for Improved Land Use
Authors: Cooper Nathanial , Panteli Anna , Shah Nilay
Published: January 2020

Biomass and the bio-economy have strong potential to help shift dependency away from petroleum. Supply chain optimisation (SCO) has been used to help other industries and can be used to boost biomass industry viability. Biomass supply chain models frequently average the biomass yield of large tracts of land in their calculations. However, there can be large variation in the biomass yield within those tracts, losing useful information. This work presents a biomass SCO framework which approximates the available quality of land by piecewise linearly approximation of the biomass yield distribution, and incorporates this information into the optimisation. The linear estimates of the biomass yield distributions allow the SCO model to make more informed decisions about quantity and location of biomass growth operations, affecting all downstream decisions. A case study of mainland Great Britain has been examined using the framework to illustrate the impact of retaining biomass yield information in the optimisation, versus averaging the yield across tracts of land. The case study found that using biomass yield linear estimates reduced the overall land usage by 10%. Further, it improved biomass output, which increased the quantity of bio-products produced. All of this led to an increase in the overall profit.
Bone-Integrated Optical Microlasers for In-Vivo Diagnostic Biomechanical Performances
Authors: Cavazos Omar , Manzo Maurizio , Ramírez-Cedillo Erick , Siller Hector R.
Published: January 2020

Bones experience mechanical loads on a daily basis. It is difficult to obtain biomechanical performances in-vivo measurements. When implants are integrated with bones after surgery, especially in aged individuals, their osseointegration can compromise the structural integrity of bones; for this reason, it is important to monitor the evolution of the mechanical properties of bones with some in-vivo diagnostic technique. In this study, we propose to integrate optical microsensing devices into bones. To simulate the working principle, a sensor is integrated with a 3-D printed bone. The sensing element is a dye-doped optical microlaser based on the morphology dependent resonance (MDR) shifts also called the whispering gallery mode phenomenon (WGM). When the microlaser is excited by a light source, the fluorescence from the dye couples with the optical resonances. These optical resonances are very sensitive to any perturbation of the microlasers’s morphology. Therefore, the local strain variation of the bone can be related to the shift of the optical resonances. This in-vivo technique monitors the biomechanical performance of bones with implants and prosthetics.
Numerical Analysis of Charging Process of a Shell and Tube Latent Heat Thermal Energy Storage System With PCM Embedded in Highly Conductive Porous Material
Authors: Mahdavi Mahboobe , Tiari Saeed , Sawyer Carley
Published: January 2020

The purpose of this study was to ascertain the effects of impregnation of porous material with the PCM on the thermal performance of a shell and tube latent heat thermal energy storage system. The heat transfer fluid flows in the tube while the phase change material is stored in the shell. A transient numerical model was developed to simulate the charging process of the system. The effects of porous material filling ratio, and its properties such as porosity and permeability, were studied on the performance of the system. The results showed that the porosity of the material or the metal foam has the greatest effect on the heat transfer and charging time of the system specifically for a filling ratio of one, or when the entire annular gap between the inner and outer tube is filled with the metal foam. As the filling ratio decreases, the effect of the porosity decreases; however, there is no linear relationship between the filling ratio and the decrease in the melting time as the porosity changes.
Discovery of Public Transportation Patterns Through the Use of Big Data Technologies for Urban Mobility
Authors: Antunes Hugo , Figueiras Paulo , Costa Ruben , Teixeira Joel , Jardim-Gonçalves Ricardo
Published: January 2020

Big cities show a wide public transport network that allows people to travel within the cities. However, with the overcrowding of big urban areas, the demand for new mobility strategies has increasing. Every day, citizens need to commute fast, easily and comfortable, which is not always easy due to the complexity of the public transport network. Therefore, this paper aims to explore the ability of Big Data technologies to cope with data collected from public transportation, by inferring automatically and continuously, complex mobility patterns about human mobility, in the form of insightful indicators (such as connections, transshipments or pendular movements), creating a new perspective in public transports data analytics. With special focus on the Lisbon public transport network, the challenge addressed by this work, is to analyze the demand and supply side of transportation network of Lisbon metropolitan area, considering ticketing data provided by the different transportation operators, which until now were essentially obtained through observation methods and surveys.
Monitoring the Cardiovascular Changes of a Rabbit Caused by Phenylephrine via a Microfluidic-Based Tactile Sensor
Authors: Wang Dan , Lattanzio Frank A. , Rodriguez Mario C. , Hao Zhili
Published: January 2020

In this work, a microfluidic-based tactile sensor was investigated for monitoring changes in the cardiovascular (CV) system of a rabbit caused by phenylephrine. The sensor was fixed on the front right leg of an anesthetized rabbit to measure the arterial pulse signal. Phenylephrine, as a vasoconstrictor, was used to introduce CV changes of the rabbit. Two sensors, one with high sensitivity and the other with low sensitivity, were tested on their suitability for measuring the pulse signals of the rabbit. The sensor with low sensitivity generated clear pulse signals and was further used to monitor the CV changes of the rabbit caused by phenylephrine. An automated sphygmomanometer and an ECG were used to record blood pressure and heart rate for comparison. Three low-dose injections of phenylephrine were sequentially performed on the rabbit. Through model-based analysis of the measured pulse signals, arterial elastic modulus, arterial radius and pulse wave velocity (PWV) were obtained. As compared with the baseline values measured before injection, injections of phenylephrine caused an increase in mean blood pressure (MAP) recorded by the medical instruments, and a decrease in arterial radius (increase in peripheral vascular resistance (PVR)) and an increase in arterial elastic modulus and PWV captured by the tactile sensor. Thus, the tactile sensor was proven to be feasible for monitoring the changes in the CV system caused by phenylephrine.