bluuebunny/crossref_metadata_2025 huggingface dataset:
Deformation Behavior of Hollow Axles With Constant Hole Diameter by Three-Roll Skew Rolling
Authors: Zhang Song , Shu Xuedao , Wang Jitai , Xu Chang
Published: February 2021

At present, hollow axles with constant hole diameter is mainly formed by turning thick-walled hollow tubes. This method of processing has low material utilization and processing efficiency. And heat treatment is required to improve the mechanical properties of hollow axles. To improve the material utilization and processing efficiency of hollow axles with constant hole diameter during the forming process, a new processing technique, three-roll skew rolling process, is proposed to form a hollow axles with constant hole diameter in this paper. The three-roll skew rolling process is a continuous plastic forming process, which has high material utilization and processing efficiency, and it can improve the mechanical properties of the rolled parts. Firstly, combining the working principle of three-roll skew rolling and the structural characteristics of hollow axles with constant hole diameter, the forming mechanism of hollow axles with constant hole diameter by three-roll skew rolling is described. Secondly, the finite element model of the hollow axles with constant hole diameter by three-roll skew rolling is established according to the dimensions of the hollow axles with constant hole diameter, the material characteristics of the hollow axles, and the stable rolling conditions of three-roll skew rolling. The process parameters of the hollow axles are also determined. Thirdly, according to each step position of the hollow axles, the forming process of the hollow axles with constant hole diameter by three-roll skew rolling is divided into 5 deformation stages. Lastly, the stress and strain field of each deformation stage of the hollow axles was analyzed. The results show that the dimensions of the hollow axles with constant hole diameter by three-roll skew rolling are very close to the designed dimensions, which indicates that the material utilization of the rolled hollow axles is very high. Along the rolling direction, the descending step of the hollow axle is easier to form than the ascending step, and the forming quality is also better. The surface metal of the rolled hollow axles flows faster than the internal metal. Areas with large stress and strain are mainly concentrated at both ends of the rolled hollow axles. And the magnitude of stress and strain gradually decrease from the surface to the center. The hollow axles with constant hole diameter by three-roll skew rolling has a good forming quality and high forming efficiency. The hollow axles with constant hole diameter is formed by three-roll skew rolling process, which has broad application prospects.
Design and Development of an Additively Manufactured Geothermal Heat Exchanger for Improved Efficiency and Easy Installation
Authors: Gemeda Takele , Estrada Sandy , Demisse Wondwosen , Wang Lei , Xu Jiajun
Published: February 2021

Effective system energy management and cooling is critical for a range of increasingly complex systems and missions. Various industries and agencies seek technologies to use energy more efficiently in various applications, and thereby increase system energy efficiencies in future advanced energy systems. There has been an increasing interest in exploiting the use of additive manufacturing in developing nontraditional energy conversion schemes. Meanwhile, wind power and solar power systems have become part of common knowledge and conversation over the past few years. While these provide excellent sustainable options of energy production, geothermal energy systems are just as efficient and economical. Solar and wind energy collectors are also site specific. On the other hand, the geothermal systems do not take up buildable ground level space nor are they location or climate specific. The earth has a generally constant temperature throughout the year which can be used in geothermal systems to benefit all sites. If all geothermal resources were combined, enough energy would be produced to provide all of the electricity needs in the United States. However, conventional geothermal system requires the relatively complex installation process and can potentially be cost prohibitive to many potential users.

In this study, an additively manufactured heat exchanger was designed and developed to resolve that issue. The heat exchanger can be integrated with a conventional geothermal heating and cooling system for improved efficiency and easy installation. A customized geothermal heating and cooling loop was designed and developed for testing the efficiency of the heat exchanger. Within this proposed system, this additive manufactured heat exchanger is designed and fabricated to improve it efficiency and easy installation with minimal tools needed. This new design eliminates the need of excavation of the soil and installation of long tubes as conventionally required for geothermal system. This new heat exchanger was designed using CREO software and fabricated using an EOS M280 direct metal laser sintering system at University of the District of Columbia. It is then integrated with a heat pump to exchange heat between a constant temperature of water bath circulator and a water heat sink. A prototype system was designed and constructed, which allowed the direct assessment of its performance. The performance of the heat exchanger is studied using COMSOL software to assess its heat transfer performance. The results have shown a significant improvement in its efficiency. It has shown the promising application of metal additive manufacturing technique in improving the efficiency of existing energy harvesting applications.
Cylindricity Sensitivity Thermal Model of the AGR-5/6/7 Experiment in the Advanced Test Reactor
Authors: Hawkes Grant L.
Published: February 2021

The AGR-5/6/7 experiment is currently being irradiated in the Advanced Test Reactor (ATR) at the Idaho National Laboratory and is approximately 70% complete. Several fuel and material irradiation experiments have been planned for the U.S. Department of Energy Advanced Gas Reactor Fuel Development and Qualification Program, which supports the development and qualification of tristructural isotropic (TRISO)-coated particle fuel for use in high-temperature gas-cooled reactors. The goals of these experiments are to provide irradiation performance data to support fuel process development, qualify fuel for normal operating conditions, support development of fuel performance models and codes, and provide irradiated fuel and materials for post-irradiation examination and safety testing. Originally planned and named as separate fuel experiments, but subsequently combined into a single test train, AGR-5/6/7 is testing low-enriched uranium oxycarbide TRISO fuel. The AGR-5/6/7 test train has five capsules with thermocouples and independent gas control mixtures.

Unique to this paper is a sensitivity study concerning the cylindricity of the graphite holders containing the fuel compacts and their eccentricity in relation to the stainless-steel capsule walls. Each capsule has small nubs on the outside used for centering the graphite holder inside the stainless-steel capsule with a small gas gap used to control temperature. Due to machining tolerances of these nubs, and vibration wearing the nubs down when the experiment is running in the reactor, the possibility exists that the holder may move around radially. Each capsule is equipped with several thermocouples placed at various radii and depths within each graphite holder. This paper will show the sensitivity of offsetting the graphite holder for various radii in 45-degree increments around the circle with the objective of minimizing the difference between the measured thermocouples and the modeled thermocouple temperatures. Separate gas mixtures of helium/neon are introduced into this gas gap between the holder and capsule wall and changed as necessary to maintain the desired thermocouple temperatures to keep the fuel compacts at a constant temperature as the nuclear reactor conditions change.

The goal of the sensitivity study is to find a radius and an angle to offset the holder from perfectly centered for each of the five capsules separately. The complex thermal model includes fission heating, gamma heating, radiation heat transfer, and heat transfer via conduction and radiation across the control gaps. Subroutines linked to the thermal model offer an easy method to offset the graphite holder from the capsule walls without remeshing the entire model.
Experimental Investigation of Friction Between Vehicle Air Bag Material and Head Skin for Humans and Crash Test Dummies
Authors: Dong Sheng , Kang Yun-Seok , Bolte John , Stammen Jason , Moorhouse Kevin
Published: February 2021

Motor vehicle crashes can produce serious head or brain injuries due to contact with interior vehicle structures. It has been found through both field data analysis and experimental testing that many of these brain injuries occur in oblique crashes, even with the deployment of air bags. Research has determined that rotational head velocity is strongly correlated to the risk of brain injury through metrics such as Brain Rotational Injury Criteria (BrIC). The severity of rotational head motion could be related to the friction force developed during contact between the head and air bags. Although crash test dummy head skins are designed with appropriate mass properties and anthropometry as well as material type and thickness to emulate the proper impact response of the human head, it is not known whether they accurately represent the frictional properties of human skin during air bag interaction. This study experimentally characterized the friction coefficient between human skin and air bag fabrics using a pin-on-disc tribometer. Skin samples were harvested from different locations (forehead, cheeks, chin) from specimens of post-mortem human subjects (PMHS). Fabric samples were cut from six different air bags spanning various vehicle manufacturers and interior mounting locations. For comparison, four types of dummy head skin samples were also tested against the air bag samples. Friction was measured between different skinair bag material combinations at various linear velocities and normal forces. It was determined that the difference between human and dummy skin friction with the air bag samples varied significantly among different air bags; however, the effect of linear speed, normal force, and human skin sample harvesting location on friction coefficient is negligible. Except for one air bag fabric, the friction coefficients of the dummy skin are higher than those quantified for human skin.
Effects of Different Cooling Methods After Demoulding on the Cornering Fatigue Resistance of the Injection-Molded Long-Glass-Fiber Reinforced Thermoplastic Composite Wheel
Authors: Zhang Yue , Liu Xiandong , Luo Jintao , Shan Yingchun
Published: February 2021

As an un-sprung rotary part of the vehicle, the wheel has a significant effect on reducing fuel consumption and emission for conventional fuel vehicles and increasing the mileage of electric vehicles, which is significantly higher than that of a spring-loaded non-rotating part. The high-performance long fiber reinforced thermoplastic composite is used to manufacture wheel through the injection molding, which not only can achieve wheel weight reduction but also provides a new way to promote wheel lightweight due to its advantages of fast molding, easy to achieve mass production, easy to recycle materials and so on. The wheel is a key safety component of a vehicle, and its performance is one of the most important factors that affect the safety of the vehicle. Therefore, the wheel made of long fiber reinforced thermoplastic composite must meet the requirements of cornering fatigue test, radial fatigue test and 13° bench impact test. In this paper, aiming at the cornering fatigue property of the composite wheel, the influence of different cooling methods on this performance of the composite wheel after demoulding are studied. The injection molding of passenger car wheels (type 5.5J × 15), composed of long-glass-fiber (LGF) reinforced thermoplastic composite (PA66+50 wt. % LGF), are fabricated under the same injection process conditions. The two cooling methods, water-cooling and air-cooling, are used to cool composite wheel to room temperature under atmospheric pressure respectively. The cornering fatigue test is carried out on the cooled composite wheels, and attain the variation curves of the maximum principal strain and the minimum principal strain with time in different directions at the test points of the spoke root of the composite wheel, respectively. In addition, during the process of cornering fatigue test of the composite wheel, the temperature change of the spokes is monitored in real-time with the aid of infrared thermal imager, and obtain the temperature distribution and change of the spokes under different load cycles. The effect of different cooling methods on the cornering fatigue performance of composite wheels is compared and analyzed based on the maximum number of cycles, the strain test results of spoke root and temperature distribution and change of composite wheel. The results show that after demouling, air cooling mode is more beneficial to improving the composite wheel cornering fatigue performance than water cooling mode. This rule is also applicable to composite wheels that are injection molded with composite materials provided by another manufacturer. The research results provide some guidance for the processing of the wheel made of long-glass-fiber reinforced thermoplastic composite.
Numerical Investigation of Convective Heat Transfer on a Dynamic Wall Heat Exchanger With Varying Amplitude and Frequency
Authors: Rahman Md. Habibur , Chowdhury Emdadul Haque , Redwan Didarul Ahasan , Prince Hasib Ahmed , Amin M. Ruhul
Published: February 2021

The current work aims to investigate the thermo-hydraulic performances of a dynamic wall heat exchanger by varying amplitude and frequency of the oscillating waveform. The lower wall of the channel is exposed to constant heat flux, the upper insulating wall is deforming in a sinusoidal waveform, and water is taken as the working fluid. The governing partial differential equations are solved by using the Arbitrary Lagrangian-Eulerian finite element method. The study has been performed in the transient regime for up to 1.0 second. At first the effects of frequency variation over the average mass flow rate, convective heat transfer coefficient, and the average liquid temperature have been observed for a particular amplitude of the dynamic wall. It has been found that the mass flow rate of water increases linearly with increasing frequency. Convective heat transfer coefficient decreases with increasing frequency up to 50 Hz, then starts to increase notably. Interestingly, the fluctuating average liquid temperature decreases and reaches a steady-state faster with increasing frequency. To explore the effect of amplitude over heat transfer characteristics, the amplitude ratio of the sinusoidal wave is varied maintaining a constant frequency of oscillation. It has been observed that with increasing amplitude, both mass flow rate and convective heat transfer coefficient increase exponentially. Increasing amplitude ratio from 0.5 to 0.9 results in an increment in the convective heat transfer coefficient by about 5 times. Although, the average liquid temperature decreases and reaches a steady state faster with increasing amplitude, initially the peak temperature of the water is recorded for the highest amplitude.
Investigation of the Secondary Crossflow at the Rectangular Exit of a Low-Speed Sectioned Contractive Wind Tunnel
Authors: Zhang Shuo , Tian Fu , Wang Xiaofang , Gao Qiang , Sui Yongfeng , Lan Jibing , Ding Xudong
Published: February 2021

The low-speed rectangular exit wind tunnel with sectioned contraction is widely used. The secondary flow vortices are found at contraction exit, which would lead to the non-uniform boundary layer and influence the aerodynamic experiment accuracy. In this paper, experimental and numerical approaches are adopted so as to clarify reasons for the formation of the secondary crossflow occurring at contraction exit and take measures to control it. The conclusions can be gotten as: the secondary crossflow is formed and developed in the second (rectangular-to-rectangular) contraction, and the first (circular-to-rectangular) contraction promote the secondary flow vortices to migrate to the middle of flow field to a certain extent; the formation of the secondary crossflow is related to the static pressure gradient in the contraction. Based on the mechanism analysis results, several methods aimed to control the secondary crossflow are proposed and verified, the results can be concluded as: in terms of the rectangular-to-rectangular contraction that contracts along one direction, it is difficult to effectively control the secondary crossflow just by optimizing contraction curves and contraction ratios, while adopting the boundary layer suction can significantly improve the boundary layer uniformity; if the rectangular-to-rectangular contraction contracts in two directions, such secondary crossflow can be well controlled.
Design and Assembly of a New Methane Generation System for Energy Conversion From Biowaste
Authors: Alhalwachi Ali , Moreno-Flores Omar , Davis Shelbie , Torrey Matthew , Altamimi Khalid , Duan Shawn
Published: February 2021

According to executive order 18-01 and 20-01 signed by the Washington State Governor, all newly constructed public buildings and facilities shall be designed to be net-zero energy capable. To respond to the governor’s order, the Washington State Department of Transportation (WSDOT) has asked for the design of a system that can use biowaste that accumulates at their safety rest stop areas to generate electricity to power the facilities. The goal of this project seeks to assist WSDOT by designing, building, and testing the capability of a small-scale methane energy generator that can be scaled to fit the needs of any rest area. There are a small number of methane generators in existence [1.]. However, they are not designed to satisfy the needs of net-zero energy facilities and safety rest areas. In this work, a net-zero methane generation system is presented to show how it can convert biowaste into methane for electricity at rest areas. The model is composed of two tanks to store the biomaterial, a filtration system to remove hydrogen sulfide (H2S) and carbon dioxide (CO2), a generator that runs on methane gas, and a photovoltaic system that powers temperature sensing devices. Through testing, it was shown that this system could generate energy through the use of bovine waste. Further improvements are needed to increase methane production and make operation more efficient. Future testing on human waste from a safety rest area will also be necessary before proving that the system can meet energy generation requirements.
Modeling Odor Optimization of Vehicles Based on Data-Driven Goal Programming
Authors: Hou Linzao , Zhang Jun , Li Mian , Zheng Ruixiang
Published: February 2021

In recent years, there is an increase in customer requirement on the comfort of vehicles. As a result, reducing the odor inside the vehicles has become an important and elusive task. Extensive experimental results show that the odor inside vehicles mainly comes from VOC (volatile organic compounds) emitted by the interior ornaments and parts. Given there are many VOC components affecting the odor, determining which VOC components are essential to the odor becomes a main difficulty in optimizing the odor in vehicles. In this paper, we proposed a new approach to optimize the odor of VOC in vehicles based on data-driven modeling and goal programming. To this end, we first collected mass spectrograms of vehicle parts and their odor ratings, where the mass spectrograms are obtained by mass spectrometer and ratings are scored by olfactory engineers. Then we used these data to build a data-driven model based on Weber-Fechner Law. The data-driven model is solved using lasso regression. Based on the data-driven model, we found out the contributions of the VOC components to the odor rating, which enables us to focus on certain specific VOC components that contribute much to the odor ratings. By strategically reducing those specific VOC components using goal programming, we finally obtained an optimized design with a better odor rating. To be specific, when performing the optimization, instead of minimizing the VOC odor rating, we set an ideal odor rating as the goal and formulated the optimization as a goal programming problem. To validate our approach, we collected 179 VOC mass spectrograms to train and test our data-driven model. The average accuracy of predicting odor ratings from mass spectrograms can reach 85% ∼ 90%. This data-driven model implies the contributions of VOC components on different mass weights to the odor rating, and the selected high-contribution mass weights can give reasonable optimization scheme to reduce the VOC gas odor.
Development and Evaluation of PVA-H 3D Printed Blood Vessel Biomodels With Several Stiffness
Authors: Kobayashi Naohiro , Shimizu Yasutomo , Nagano Ryota , Tupin Simon , Ito Makoto , Ohta Makoto
Published: February 2021

Biomodels, which are models of tissues such as blood vessels, have recently come into high demand for surgical training or medical device assessment use. Since the stiffness of blood vessels is not uniform, reproducing this nonuniformity would be advantageous to producing more realistic models, and to do this, we used a poly (vinyl alcohol) hydrogel (PVA-H) 3D printer. As a material, recently PVA-H has received increasing attention. This printing technique may be suitable for fabricating models composed of parts exhibiting different levels of stiffness (multipart models).

However, the PVA-H 3D printer uses outer molds as supports. Outer mold removal as a post-process might affect the mechanical properties of the models or other post-processes such as ethanol substitution, and this requires investigation. Quality checks on the mechanical properties of the final product are also necessary.

In this study, the effect of outer molds on the efficiency of ethanol substitution was estimated by measuring specimen weights. Additionally, the effect of the heat generated when molds were removed with an ultrasonic cleaner on the Young’s modulus of models was tested using tensile tests. Moreover, multipart pieces were fabricated, and their mechanical properties were measured.

The findings were that ethanol substitution was able to be completed by conventional methods. Furthermore, the heat generation did not change the Young’s modulus of the models. Also, it was possible to fabricate multipart PVA-H models, and their level of stiffness followed the theoretical equation that assumes constant stiffness and independency of each part. The PVA-H 3D printer, therefore, has the potential to fabricate multipart models that will enable better surgical training and device assessments.
Effect of the Number of Stages on the Performance of Savonius Vertical Axis Wind Turbines: Part II — Using Twisted Blades
Authors: Saad Ahmed S. , Ookawara Shinichi , Elwardany Ahmed , El-Sharkawy Ibrahim I. , Ahmed Mahmoud
Published: February 2021

Wind energy comprises one of several renewable resources of energy engineered to contain the global energy crisis. Although horizontal axis wind turbines (HAWTs) have proven to be effective in low turbulence and steady wind conditions, vertical axis wind turbines (VAWTs) potentially have the advantage in highly variable and turbulent regions. The Savonius vertical axis wind turbine has several advantages such as simple design, low manufacturing costs, low operating wind speed, low noise, and Omni-directional capability. However, the Savonius rotor requires further design optimization to improve its aerodynamic performance before becoming competitive with other turbine designs.

Thus, the main objective of the current study is to numerically investigate the aerodynamic performance of a multistage Savonius rotor to enhance the power coefficient and the ability of self-starting. In the current study, one-, two-, three-, and four-stage Savonius rotors with twisted blades are investigated. In a two-stage rotor, one single-stage rotor is mounted over another single-stage with a phase angle of 90°. In a three-stage rotor, the three single-stage rotors are mounted one above the other with a phase angle of 60° relative to one another while with a phase angle of 45° for the four stage-rotor. The blades of the studied Savonius rotor are twisted with a twist angle (φ) of 45°.

This is the first contribution to understand how multi-stages influence the aerodynamic performance of the twisted-bladed Savonius rotor. Moreover, variations of torque and power coefficients are computed for all the studied rotors with various numbers of stages. The developed numerical model is simulated using ANSYS Fluent and validated using the available experimental and numerical results. Results showed that the coefficients of torque (CT) and power (CP) increase with rising the number of stages. Increasing the number of stages from 1 to 2 significantly increases the CT and CP of the rotor. However, with a further increase in the number of stages to 3 and 4 stages, both the CT and CP remains almost the same as the rotor with 2 stages. The maximum coefficient of torque (CT, max) and power (CP, max) for a two-stage rotor are 0.42 and 0.253, respectively. The gain in the coefficient of power obtained by using the two-stage Savonius rotor with twisted blades is 53.5% compared to the conventional single-stage which has a coefficient of power 0.165 at a wind velocity of 6 m/s. Moreover, using multi-stages and twisted blades significantly smooth the variations in the generated torque and produce positive values at all rotor angles resulted in improving the self-starting ability of the Savonius rotor.
An Experimental Study on the Analysis of Operating Conditions in the PEMFC Flow Channel by Observing Temperature/Humidity Field
Authors: Han Jaesu , Yu Dongjin , Yu Sangseok
Published: February 2021

Proton Exchange Membrane Fuel Cell (PEMFC) has advantages that other energy sources don’t have, and recently, it has been spotlighted in many industries such as transportation and power generation. However, although much research has been conducted on PEMFC, studies on operating conditions of bipolar plates in cells have been insufficient. Most of the studies that have been conducted so far are obtained by setting a few points on the edge or the latter line of the bipolar plate when acquiring data such as the operating temperature or relative humidity of the cell, so the research is extremely limited. In order to maximize the performance of PEMFC and preserve its durability, it is very important to control operating temperature and humidity optimally. Typically, water contents inside membrane electrolyte is determined by externally delivered water vapor and electrically reacted water vapor. Since water vapor is delivered and exhausted through bipolar plate, the vapor concentration in the bipolar plate is a clue to understand operating characteristics of PEMFC. Even though vapor concentration is a key to improve the performance, it is very difficult to measure direct distribution on the membrane electrode assembly. Therefore, this study attempted to observe the behavior of vapor flow inside the bipolar plate. By mounting several sensors in the flow path of the bipolar plate, it is possible to measure the temperature and humidity field data in the flow path, so that it is possible to observe the actual operating environment in the stack under various operating conditions and to establish a control strategy. Especially, this approach not only makes it possible to analyze the static water content in a steady state where no change in load occurs, but also enables dynamic observation of transient characteristics in the flow path when the current density changes. Several temperature and humidity sensors were installed on the bipolar plates of the cathode and anode respectively, and reliability and performance evaluations were performed through experiments. Reliability was evaluated by setting up a relatively accurate comparison sensor among the existing sensors that were not used in this study, and analyzed the effects of flow disturbance in the flow path by comparing with the polarization curve in the general cell. After the sensor calibration, an experiment was performed to obtain temperature and humidity data as the current density changed. As a result, it was possible to quantitatively analyze the water content delivered from the outside or generated inside the stack.
Robustness Optimization of Product Assembly Architecture for Personalization
Authors: Tan Changbai , Freiheit Theodor , Barton Kira , Banu Mihaela , Hu S. Jack
Published: February 2021

Personalization has received extensive attention as a new manufacturing paradigm to address increased market demand for personalized products. An open product architecture that assembling common, customized, and personalized modules is regarded as a key enabler for product personalization, which can deliver one-of-a-kind products for individual customers at near mass production efficiency. Offering the best product architecture should consider the variations in design variables and parameters that influence the performance of a product architecture. This is especially true when designing open architecture for personalized products as many uncertain design quantities need to be considered in early product design stage.

A robustness optimization method is proposed to simultaneously optimize product variety, module variant selection, and configuration of personalized module variants for a personalized assembly architecture. First, a profit model is developed to measure the performance of a product architecture, which incorporates individual customer preferences and manufacturing cost. A three-step process is proposed to model heterogeneous customer preferences: conjoint analysis of the preferences of a sample of customers from target market, market segmentation by a multi-variate normal mixture method, and simulation of personal preferences for a broader market by Monte-Carlo simulation. Thus, the simulated individual customer preferences are used to predict the sales and profit of product offerings. Second, the variation of profit associated with a product family architecture due to the uncertainty in customer preference and manufacturing cost estimates is formulated by a sensitivity analysis. A robustness index is defined by combining the objectives of maximizing profit and minimizing its variation. Lastly, a robustness optimization model is established to optimize product architecture by maximizing its robustness index. The proposed method is demonstrated with a personalized bicycle architecture design example.
A 3D Finite Element Analysis Study of the Jawbones Response to Osseodensification and Conventional Drilling
Authors: Alaqeely Razan , AlDosari Mohammad , Babay Nadir , Abdulbari Al-Hussain , Ba Hadi Ala , Ben Yahia Faycal , Abdulghani Mohannad
Published: February 2021

Osseodensification is used to densify natural bone and increase dental implant stability. This work aims to compare, using finite element analysis, the stress generated on different jawbone areas between conventional drilling (OD) and osseodensification drilling (CD). Cone-beam CT scans of four different edentulous patients were obtained. Implant insertion and removal in the four bone models were simulated for the two different drilling techniques. Materials distribution was set as homogeneous throughout each part. In the OD technique, a new densified region was formed with new material properties based on a relation between density and elasticity. Material distribution of the densified regions was assumed to be a non-homogenous linear pattern and its gradual variation complies with the graph-related slope equations. Von-Mises stress for cortical and trabecular bone was significantly higher in the CD model in comparison to their values in the OD, as densified regions have absorbed most of the stresses and restricted their propagation. The same phenomenon was observed in the implant pull-out bone model. The OD technique was found to affect the primary stability of dental implants positively. The bone types present in different jawbone regions react differently to this technique according to the percentage of trabecular bone to cortical bone.
A Creative Vibration Energy Harvesting System to Support a Self-Powered Internet of Thing (IoT) Network in Smart Bridge Monitoring
Authors: Farhangdoust Saman , Mederos Claudia , Farkiani Behrouz , Mehrabi Armin , Taheri Hossein , Younesian Davood
Published: February 2021

This paper presents a creative energy harvesting system using a bimorph piezoelectric cantilever-beam to power wireless sensors in an IoT network for the Sunshine Skyway Bridge. The bimorph piezoelectric energy harvester (BPEH) comprises a cantilever beam as a substrate sandwiched between two piezoelectric layers to remarkably harness ambient vibrations of an inclined stay cable and convert them into electrical energy when the cable is subjected to a harmonic acceleration. To investigate and design the bridge energy harvesting system, a field measurement was required for collecting cable vibration data. The results of a non-contact laser vibrometer is used to remotely measure the dynamic characteristics of the inclined cables. A finite element study is employed to simulate a 3-D model of the proposed BPEH by COMSOL Multiphasics. The FE modelling results showed that the average power generated by the BPEH excited by a harmonic acceleration of 1 m/s2 at 1 Hz is up to 614 μW which satisfies the minimum electric power required for the sensor node in the proposed IoT network. In this research a LoRaWAN architecture is also developed to utilize the BPEH as a sustainable and sufficient power resource for an IoT platform which uses wireless sensor networks installed on the bridge stay cables to collect and remotely transfer bridge health monitoring data over the bridge in a low-power manner.
Web Based Application for Quick and Handy Health Condition Monitoring System for a Reliable Wind Power Generation
Authors: Kumar Verma Amar , Radhika Sudha , Surampudi Naren
Published: February 2021

Health condition monitoring in wind turbine motor plays an extremely important role, as these devices are highly in demand in the energy sector, especially in renewable energy and are vulnerable to both mechanical and electrical failures, more often. As such, timely identification of internal faults in these electrical devices goes a long way in productive operations by reducing the maintenance time and costs, i.e. such internal faults, if identified at an early stage, repaired or replaced timely will aid in reliable renewable energy supply. Taking this into consideration, automated continuous monitoring of wind turbine machine is a key to making this process more effective. A web application is built in the proposed research enabling quick monitoring of faults in wind turbine motor from a remote access workstation, like a control room. An experimental setup of wind turbine motor is made and data set of stator currents from both healthy and faulty conditions as well as the power spectral density from the motors were used for condition monitoring with a web interface application. Insulation failure in stator winding is a most commonly occurring electrical failure in machines. As such in the current research stator current features from the experimental machine are used for requirement analysis under both healthy and faulty operating conditions. Among the stator insulation failure most commonly occurring stator turn-to-turn faults are taken into consideration in the current research with percentage of insulation failure varying between 25% to 75%. Fault identification is done with the help of wavelet based artificial neural network analysis at the back end and the interface displays the details in the form of dashboards, with the program mainly featuring three dashboards for the unit, stator, rotor, and components in total. Using interactive visualizations, the user will be able to obtain more in-depth knowledge about the suspected faults in the system and its components, and help to take the necessary action. i.e. whether the wind turbine motor needed to be repaired or replaced depending on the vulnerability of the fault. The application also has been experimented with handheld devices by hosting the application on local host and tunneling it over the web. Interactive visualization also includes information about the working conditions of the electrical machine, such as balanced, unbalanced, and failure conditions. Thus internal electrical fault in a wind turbine induction machine can be remotely analyzed, checked and cure can be suggested with a proper online health condition monitoring system.
Thermal Analysis of Large Area Additive Manufacturing Resistance Heating Composites for Out of Oven/Autoclave Applications
Authors: Billah Kazi Md Masum , Hassen Ahmed Arabi , Nasirov Aslan , Haye Gregory , Heineman Jesse , Kunc Vlastimil , Kim Seokpum
Published: February 2021

Additive Manufacturing (AM) of carbon fiber (CF) reinforced composite has received growing attention because of the design flexibility, superior mechanical properties, improved thermal properties, and weight reduction. Autoclave tooling was proven to be a successful application for large scale AM technology. The capital cost, and cost associated with heating, and cycle time in a conventional autoclave process is relatively high. Thus, an innovative design of AM mold with an efficient heating scheme is essential. This study represents an innovative method of the resistive heating of composite molds which does not require a room size oven for heating during the curing processing. Therefore, it has the potential to reduce the operating cost drastically. For the design validation and feasibility study, we performed a numerical analysis of the wire embedded and AM mold parts. The goal of this study is to determine and optimize the thermal behavior of the printed mold with embedded wire technology. It is anticipated that the larger distance between the embedded wires along the printing direction (z-direction) increase the cold spot, on the other hand, a close distance of the wire can create the unwanted localize heating, thus melting. Constant thermal properties of the 20 wt.% short CF reinforced acrylonitrile butadiene styrene (ABS) was used for the simulation purpose. Thermal characterization was set to 100°C to avoid the thermal deformation or bulging on the part surface.
Gravity Compensation Walker: Structure and Safety
Authors: Felmlee Robert , Smith Jordan , Macaulay Michael , Leamer Dakota , Budd Ethan , Steinbrink Scott , Piovesan Davide , Crowe Mary
Published: February 2021

Morbid obesity is a widespread problem in the united states. The rate of falls and injures is much higher for obese individuals when compared to individuals of normative weight. Obesity can also impose excessive load to the hip and knee joints during the sit-to stand transition, which is conducive to osteoarthritis and increased sedentariety.

In order to help individuals with the aforementioned problems, a sit to stand assistive device can be created that compensates for the subject’s lack of propulsive force. This device can reduce the chances of falling while trying to stand and help professionals when aiding these individuals in the healthcare setting. Users can interact with the propulsive loading provided by the device, which can be customizable to their needs. This product is one of the few sit to stand passive, assistive devices allowing the individual to use lower body strength and very minimal upper body strength. The objectives of our device are to be adjustable, help individuals stand without falling forward, be relatively inexpensive, easy to use, and safe for a hospital environment. Structural and stability analysis of the device is here presented, to assess the safety of its use.
A Logistic Regression Analysis for Tissue Stiffness Categorization Through Magnetic Resonance Elastography
Authors: Ramzanpour Mohammadreza , Hosseini-Farid Mohammad , McLean Jayse , Ziejewski Mariusz , Karami Ghodrat
Published: February 2021

Magnetic resonance elastography (MRE) is commonly used as an image-based alternative for palpation of the internal organs of human body. The presence of tumor or other kind of pathologies in biological tissues can increase its stiffness. Therefore, while MRE technique is capable to provide a quantitative measurement, the qualitative description of the tissue stiffness could be potentially informative as well for physicians. MRE can be divided into several steps including the generation of waves in the tissue, measuring the field displacement of the tissue by magnetic resonance imaging devices, and then applying the constitutive based inversion algorithms to measure the material properties of the tissue. The inversion algorithms are dependent to the constitutive model in use, and moreover, it could be computationally expensive. To overcome this hindrance, in this paper, we propose a machine learning framework for categorizing the tissue stiffness based on the magnetic resonance elastography finite element simulation data. In our finite element simulation, the shear waves are generated in an axisymmetrical model by applying harmonic displacement at the center of the model with the known excitation frequency. To obtain the field displacement of the model, in the first step, the natural frequencies of the system will be calculated through numerical Block-Lanczos eigensolver algorithm. Thereafter, a transient dynamic modal analysis is carried out to find the corresponding displacement response of the tissue in different time steps of the simulation. To obtain the training dataset, ten simulations with the pre-assigned linear elastic modulus in the range of 2 to 6 kPa is conducted and the displacement of the tissue in three points at the end of the first and second cycle will be recorded as the features of the dataset. Each instance of the dataset is labelled as “Low“ or “High”, corresponding to its stiffness quantitative value lying in ranges of 2–4 kPa or 4–6 kPa. A machine learning classifying algorithm, a logistic regression hypothesis will be trained on this dataset. The trained hypothesis will be then tested on six new unseen simulation data with known elastic modulus values. The trained logistic regression was able to classify the tissue stiffness with the perfect accuracy score of 1.0. The findings of this study can be used for qualitative description of the tissue stiffness that can be beneficial for pathology diagnosis and moreover, it eliminates the need on the usage of inversion algorithms which leads to reduction in the computational complexity of tissue characterization.
Towards Implementing a Collaborative Manufacturing Cloud Platform: Experimenting Testbeds Aiming Asset Efficiency
Authors: Santos Nuno , Monteiro Paula , Morais Francisco , Pereira Jaime , Dias Daniel , Pimenta Daniel , Carvalho Márcia , Melo Mónica , Mendonça João P. , Oliveira Eduardo , Silva Leopoldo , Pereira Fernando , Carvalhal João P.
Published: February 2021

Developing Industrial Internet of Things (IIoT) systems requires addressing challenges that range from acquiring data at the level of the shopfloor, integrated at the edge level and managing it at the cloud level. Managing manufacturing operations at the cloud level arose the opportunity for extending decisions to entities of the supply chain in a collaborative way. Not only it has arisen many challenges due to several interoperability needs; but also in properly defining an effective way to take advantage of the available data, leading to Industrial Digital Thread (IDT) and Asset Efficiency (AE) implementing. This paper discusses implementation concerns for a collaborative manufacturing environment in an IIoT system in order to monitor equipment’s AE. Each concern was addressed in a separate proof of concept testbed. The demonstration is based in a project for the IIoT domain called PRODUTECH-SIF (Solutions for the Industry of the Future).
Biomechanical Study of Cervical Disc Arthroplasty Devices Using Finite Element Models
Authors: Purushothaman Yuvaraj , Choi Hoon , Yoganandan Narayan , Baisden Jamie , Rajasekaran Deepak , Jebaseelan Davidson
Published: February 2021

Various types and designs of artificial discs for cervical disc arthroplasty (CDA) have been introduced to overcome the disadvantages of the conventional anterior cervical discectomy and fusion (ACDF). The purpose of this study was to evaluate the effects of different CDA designs on the range of motion (ROM), intradiscal pressure (IDP), and facet force variables with different types of FDA-approved CDA devices under normal physiological loading conditions. A validated three-dimensional finite element model (FEM) of the intact cervical spinal column (C2-T1) was used in the present study. The intact spine model was modified and used for postoperative FE models simulating CDAs implanted at the C5-C6 intervertebral disc space. The normal surgical procedures were used in the simulations. The hybrid loading protocol (intact spine loading: 2 Nm) with a compressive follower force of 75 N was applied at the superior end of the spine. The inferior endplate of C7 vertebra was constrained in all directions. Flexion, extension, and lateral bending loading conditions were simulated in all models: intact spine and models with different CDA devices. At the index level, all CDAs except the Bryan disc showed an increase in motion, and the range of motions at the adjacent levels decreased in flexion, extension, and lateral bending modes. The largest increase in motion occurred during lateral bending. The Bryan disc reduced the segmental motion at the index level under flexion, extension, and lateral bending, and had compensatory increases in motion at the adjacent levels. The intradiscal pressure reduced at the adjacent levels with Mobi-C and Secure-C devices. The Bryan and Prestige LP devices showed increases in the intradiscal pressure at the adjacent levels due to the reduced index level motion (Bryan disc) and the metal-on-metal design (Prestige LP). The facet force increased at the index level in all CDAs, with the highest force with Mobi-C, and this was attributed to its unrestrained design. The facet force generally decreased at the adjacent levels with CDAs, except for the Bryan disc, due to reduced index level motion, and the Prestige LP in lateral bending, likely due to its metal-on-metal design. The present study demonstrates the influence of different CDA designs on the anterior and posterior loading patterns at the index and adjacent levels. In addition, the study validates key clinical observations: CDA procedure is contraindicated in cases of facet arthropathy; and CDA may be protective against adjacent segment degeneration.