bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulated Model for a New Design of Thermal Energy Storage System
Authors: Elsharafi Mahmoud , Elmozughi Ali , Pokharel Pranaya , Holmes Clayton , Krahl Madison , Aldawsari Musaad , Rolle Theo
Published: January 2022

The importance of this article is to study of Phase Change Materials (PCM) in thermal energy storage systems using simulation Software, ANSYS, to conduct Thermal Computational Fluid Dynamic (CFD) studies. Because of the versatile nature of latent heat thermal energy storage systems, it is pertinent to conduct further studies. SolidWorks is used to create precise 3D models of Tranter Heat Exchanger Components. This purpose is to extract the volume between plates of an actual Tranter Heat Exchanger System. Also, in this model, located in a custom-made chamber of Poly (Methyl Methacrylate) or plexiglass, contacting the heat exchanger plate is the volume in which the phase change material (PCM) is stored to be melted and retrieved to obtain stored energy. A PCM is a medium that is capable of absorbing and releasing energy as the phase changes occur in low temperature, in our case from solid to liquid and conversely. Due to this process, it is necessary to study the various types of latent heat storage materials. Transient heat transfer analysis is conducted to investigate low temperature energy storage using corrugated thermal flow channel for lower temperature applications. The enthalpy porosity method is applied to simulate model in pure conduction. The PCM used in the study is the Paraffin C22−C45 packed in the chamber and contacted to corrugated stainless steel plate. Energy storage into PCM and energy retrieval from PCM is simulated in turbulent flow of the heat transfer fluid. Other key variables consist of time temperature, pressure, turbulent type flow, and properties of H2O and Paraffin C22−C45. The use of ANSYS Software can determine distribution of heat throughout the unit, and witness the melting process simultaneously unlike in physical testing. Due to the simulation’s quick nature, relative to physical testing, in future, multiple experiments can be performed with various phase change materials, calculations on the total energy stored can be performed quickly, and power recovery can be estimated based on the simulation results. The novelty of the work is demonstrated in simulation of PCM that is stored above a volume generated from combined complex ‘chevron’ shaped plates. The goal is to compare the results of the simulation to corresponding simulations. Due to the nature of the plate and its arrangement, it is correctly observed from the simulation that the melting of the PCM begins at the center of the plate where maximum heat transfer takes place.
Estimates of Area, Output and Levelized Energy Cost of Wind Energy Schemes in Saudi Arabia
Authors: Abdulghani Mohannad , Alabdulkarem Abdullah
Published: January 2022

Renewable energy is experiencing a surge in the Middle East and North Africa. Investigations of the economic feasibility of utility level renewable energy projects are necessary for such projects to become part of the zeitgeist of power generation in the region and be viewed as a sustainable clean alternative. Saudi Arabia, with the advent of Vision 2030, has placed renewable energy as a key pillar of its energy policy with several renewable energy projects planned and commissioned in the past couple of years. Although Solar Energy seems like an obvious choice for Saudi Arabia, owing to its location and the amount of solar irradiance it experiences annually, there remain unanswered questions about this option’s viability. Several investigations into the financial efficacy of large-scale solar projects in the kingdom have raised concerns about their economic feasibility. Wind turbines have the potential of resolving the economic questions about renewable energy as a source of power for domestic consumption to cover the Kingdom’s growing energy demands. The power generation capacity of Saudi Arabia has grown exponentially due to several factors such as modernization and a population boom in the past five decades, thus necessitating finding clean energy alternatives. In this work, estimates of area, energy output, and levelized energy cost for a large, utility-scale, energy scheme is obtained using a RETScreen model, which is informed by up-to-date figures from the region. The levelized cost of energy, area required, and energy output of a wind power plant with a nameplate capacity — the full load of the power plant as intended — equivalent to the country’s peak load demand is estimated. The levelized energy cost resulting from the model is compared with the current unsubsidized costs of energy in the kingdom.
A Safety-Space-Based Approach to Inspection Path Planning for the Sheet Metal Assemblies
Authors: Liu Yinhua , An Chao , Duan Zhenxia
Published: January 2022

The inspection path planning of sheet metal assemblies plays an important role in the measurement efficiency of large free-form surfaces. In the path generation of a 5-axis coordinate measurement machine (CMM), large calculation of collision detection and obstacle avoidance are needed in the traditional computer-aided inspection planning methods. Owing to structure complexity of large free-form surfaces, the planning procedures for collision detection and automatic collision-free trajectory generation is time-consuming and low-efficiency. To address this problem, a safety-space-based modeling approach is proposed to generate a feasible collision-free path for a large number of key measurement points. At first, based on the decomposition of the dynamic motion trajectory of the probe and discretizing of the inspected object, a continuous envelope space, i.e., safety space is constructed for candidate path generation of the probe. In the proposed planning strategy, the work of collision detection and avoidance are eliminated. Then, a heuristic optimization algorithm is used to generate the feasible trajectory in the constructed safety space for all the measurement points. At last, an inspection path planning case of a car door assembly was used to illustrate the procedure of the proposed method.
Combined Time- and Frequency-Domain Aircraft System Identification Using Pareto Optimization
Authors: Stachiw Terrin , Ricciardi Joseph , Crain Alexander
Published: January 2022

Aircraft system identification can either occur in the time-or frequency-domain with each approach having inherent advantages and disadvantages. For example, time-domain modelling generates superior time history matches and has a superior ability to achieve a trim solution. However, time-domain models do not provide a high degree of insight to the frequency responses of the system, which is important for control law development and for matching handling qualities for pilot-in-the-loop simulation — this is a strength of the frequency-domain approach. This paper utilises a Pareto optimization procedure to combine both the time- and frequency-domain approaches and exploit the strengths of both methods. Pareto fronts are generated for the system identification of a 6 degree-of-freedom forward flight model at 90 kts of the National Research Council of Canada’s Bell 412 helicopter. The generated Pareto fronts showed the necessity of balancing the time- and frequency-domain matches whereby moving from the compromise solution to either the isolated time- or frequency-domain solutions resulted in a small improvement in one while the other suffered relatively more. Accordingly, the multi-objective solution using Pareto optimization capitalized on the strengths of both approaches and avoided an overspecialized solution in either of the domains.
Probabilistic Response of a Vibration Energy Harvester With Customized Nonlinear Force Driven by Random Excitation
Authors: Devarajan K. , Shankaranarayanan V. , Nithishrajan K. , Gaouthaman M. , Chandraditya B.
Published: January 2022

Nonlinear restoring forces have been widely introduced into the harvesting of vibratory energy to enhance energy harvester performance. Generally, the various source of nonlinearity include magnetic forces, spring forces, geometric and material nonlinearity, etc. However, these kind of nonlinear forces cannot be manipulated in an arbitrary manner. The performance of the energy harvester can be further optimized if the nonlinear forces are manipulated according to the requirements. The aim of this work is to study the energy harvesting performance of vibration energy harvester that can customize the nonlinear forces subjected to Gaussian white noise. The approximate analytical solution is obtained by moment differential method for the vibration energy harvester and there is a good agreement between analytical and the numerical solution obtained by Euler Maruyama scheme. Mean squared output power is presented to illustrate the device output performance. The nonlinear forces are customized For monostable and bistable piezoelectric energy harvester and the influence of noise intensity, and effect of system parameters on the response of the energy harvester is analyzed both numerically and analytically. The effect of stochastic resonance on the performance of the system also analyzed numerically for the bistable energy harvester.
Measuring Sustainability and Operational Performance by Engineering Students In University-Business PBL Partnerships
Authors: Alves Anabela C. , Abreu M. Florentina
Published: January 2022

This paper describes an assignment given to fourth-year Industrial Engineering and Management (IEM) students in a Project-Based Learning (PBL) developed in the context of university-business partnerships. The aim of this assignment was students assess sustainability business effectiveness in an industrial context. To achieve this, they must use an indicator that was explained in the context of Lean-Green synergy, a content lectured in the course Production Systems Organization II (PSOII) of the fourth year IEM program of the School of Engineering at University of Minho. This course is one of the five courses which contents must be integrated into the Integrated Project of Industrial Engineering and Management II course, under PBL. Students worked in teams of 6–10 students and developed their projects in companies. The cohort of 2020–21 involved 12 teams in a total of 100 students. In each company, teams had a supervisor that supported and supervised their work. Teams had to organize themselves to attend lectures in university and visit the companies according to companies’ availability, which was difficult by the pandemic situation. The project developed under PBL is related to the analysis and proposals improvements for companies’ production system applying the knowledge and contents learned in courses of fourth or previous years. Taking into account the results obtained in the indicator used, the teams had to propose some environmental and operational improvement actions to increase it. The teams’ main findings, the sustainability learning process, and outcomes are discussed in the paper.
Sizing Optimization of District Energy Systems Considering Meteorological, Demand, and Electricity Emission Factor Uncertainties
Authors: Ghaemi Zahra , Tran Thomas T. D. , Smith Amanda D.
Published: January 2022

In this study, a framework is developed to perform two-stage stochastic programming in a district energy system. This framework optimizes the sizing of energy components to minimize the total cost and operating CO2 emissions. Uncertainties in electricity demand, solar irradiance, wind speed, and electricity emissions are considered. A group of buildings at University of Utah is used as the case study to test the optimization framework. This study is novel by forming an open-source framework, considering electricity emissions with more details compared to previous studies in the literature, and performing the optimization for a campus in the U.S. This study’s results show the trade-off between cost and emissions when different energy configurations are used for three electricity purchasing cases. This framework can help facility managers to evaluate the optimum sizing of their district energy system to minimize the cost and emissions.
Efficient Feedrate Optimization Method for Spline Toolpath Based on Typical Characteristics of Integral Impeller
Authors: Xiao Jianxin , Li Bingran , Fang Jun , Zhang Hui
Published: January 2022

As a relatively complex part of aero-engine turbine blades, the integral impeller is characterized by complex space, high steepness, and distortion. An actual five-axis computerized numerical control (CNC) machining process unaffected by the machining quality and accuracy of a large curvature range. Consequently, knowing how to reasonably adjust the feed speed of a path in view of further improving the efficiency has always been difficult. This research adopts the method of combining computer-aided manufacturing (CAM) and CNC and proposes a direct interpolation algorithm for the double non-uniform rational B-spline curves based on the typical characteristics of the integral impeller. First, in the CNC, the integral impeller is divided into high-speed regions and three-dimensional characteristic parameters of the integral impeller in CAM. Second, in the low-speed area, the feature-divided high- and low-speed areas are discretized on the basis of the interpolation period and equal arc length. Then, the low-speed area speed is adjusted to meet the kinematic constraints according to the dichotomous configuration. Finally, the discrete speed is smoothly filtered by the Finite Impulse Response (FIR) filter to be able to meet the dynamic response characteristics of the machine tool. Simulations and experiments show that the algorithm can effectively improve the speed and smoothness of the inlet and exhaust edges of the overall impeller, effectively reduce the calculation amount of the numerical control system, and improve the overall machining efficiency of the impeller under the requirements of machining accuracy.
Abrasive and Cutting Element Use in Friction Element Welding
Authors: Grimm Tyler J. , Deshpande Amit B. , Mears Laine
Published: January 2022

Increasing awareness of the global warming effects of greenhouse gas emissions has caused governments to impose strict regulations requiring significant improvements in vehicles’ fuel economy. These regulations have required automotive manufacturers to revise traditional designs. An effective method of improving fuel economy is through lightweighting, which can be achieved by incorporating multi-material designs. However, this method presents difficulty in manufacturing since traditional joining methods, such as resistance spot welding, cannot in many cases be directly used.

Many advanced joining methods have recently been developed to enable multi-material joining. Friction element welding (FEW) is one such process which can join aluminum sheets to steel without any required pre-hole drilling. In this process, the fastener is rotated and driven into the aluminum sheet, producing frictional heat which causes the aluminum to flow around the fastener shaft. In a successful joint, this aluminum flow remains near the shaft of the element and is covered by the element’s head upon welding. However, when joining high-strength aluminum alloys, the flow is hindered and aluminum protrusions are formed which extend beyond the cover of the element’s head. These protrusions, termed chips, are known to increase corrosion and should be eliminated. A novel method of reducing this effect is explored which utilizes modified elements to increase friction between the element and the aluminum sheet, causing accelerated heating. Additionally, a modified tip design is tested which aims to cut through the aluminum sheet. These methods were found to reduce chipping; however, chipping could not be eliminated. It was concluded that this is not a viable method of addressing the chipping issue in FEW.
Thermocapillary Flow of a Moderate-Prandtl Number Fluid in Annular Pools With a Heat Inner Cylinder
Authors: Mo Dong-Ming , Zhang Li , Ruan Deng-Fang , Li You-Rong
Published: January 2022

In this paper, a set of direct numerical simulations on the thermocapillary flow of 2cSt silicone oil with Prandtl number of 28.01 in annular pools heated from inner cylinder were carried out. The critical Marangoni number of flow destabilization was determined, and the flow pattern evolution with Marangoni number was revealed when the aspect ratios of the annular pools were 0.375 and 0.75. It was found that the axisymmetric steady flow will transit into different types of oscillatory flows. The critical Marangoni number of flow destabilization depends on types of flow instability. At a small aspect ratio, the flow transits to the oscillatory concentric ring pattern firstly, then into the combination of the oscillatory concentric ring pattern and azimuthal non-uniform temperature fluctuation, and eventually into rotating wave, while it transits directly into the rotating wave at a large aspect ratio. With the increase of Marangoni number, the oscillation frequency of the oscillatory flow increases, and the wave number is almost unchanged. However, when the oscillatory flow pattern transition happens, there is always an abrupt drop of the oscillation frequency.
Multi-Physics Topology Optimization for Efficient Spacecraft Design
Authors: Corrado Casey R. , Ramos-Carrizosa Francisco F. , Neu Samuel C.
Published: January 2022

The current development process for spacecraft consists of designing for mission goals first and mitigation for environmental requirements second. Environmental issues often arise late in the design process, leading to longer design times and less efficient use of the available volume and mass. Faster and more efficient development of spacecraft can be achieved through a novel design methodology, Multi-Physics Topology Optimization (MPTO). The work presented provides an overview of a MPTO for small satellite design, combining thermal management and structural design into a single, streamlined process. This method results in a more effective use of allotted mass and volume, providing opportunities to increase system functionality. An example case is provided using an existing 3U CubeSat, where the proposed methodology was used to improve specific performance attributes. As topology optimization technologies continue to develop, this method can be expanded to include new capabilities, such as multi-material optimization, as well as new objectives, such as optical and electrical performance.
Influence of Volumetric Dilation of Microstructural Phases on Residual Stress Distribution in Laser Welded Ti-Alloy
Authors: Kumar Bikash , Bag Swarup , Amin M. Ruhul
Published: January 2022

The accurate assessment of welding induced residual stress field is always of significant interest due to its adverse effect on the structural stability and mechanical performance of welded structure. Incorporation of intricate phenomena, in particular, thermal gradient, phase development, volumetric dilation, and phase transformation strain during FE modeling, not only act as a reliable method for residual stress calculation but also serves as a directive to reduce tensile residual stress in a weldment, which is sensitive to the selection of materials. To investigate the same for continuous and pulse laser welded Ti-6Al-4V alloy, the sequential coupled thermal-metallurgical-mechanical models are established. The internal state-dependent variables (SDVs) are implemented to capture the growth of phase evolved during diffusionless β → α′ transformation using Koistinen-Marburger (K-M) theory in the cooling cycle. The role played by a phase transformation induced strain on the generation of residual stress is systematically investigated. The volumetric dilation and associated phase fraction form the basis for the calculating of phase transformation strain in the present study. The accomplishment of highest martensitic fraction, i.e., 95 %, produced a phase transformation strain of 7.95 × 10−3 in pulse mode of operation. As a result, reversal of residual stress from tensile to compressive is perceived for pulse-welded specimen. Enrichment of martensitic phase fraction puts the weld surface into a compression state that mitigates the overall tensile residual stress in a welded structure.
The Use of the Discrete Element Method to Study the Response of Packed Particles to a Pressure Wave
Authors: Florio Catherine S.
Published: January 2022

While a system of particles confined in a container forms a structure-like system, its response to mechanical loads has characteristics that are both similar to a comparable continuum and unique to the discrete nature of the particles. Even when packed together, local interactions are often discontinuous throughout the system and over time, resulting in complex local and bulk behaviors. The effects of the properties of the particles and their interactions may, therefore, result in local forces and stresses in response to a pressure wave that cannot be readily modeled by continuum based computational modeling methods. This work uses the discrete element method (DEM) to improve the understanding of the model and system parameters that influence the local interactions of individual particles, the forces that develop, and the energy that is stored or dissipated as a pressure wave passes through a confined system of particles. Loads with durations that varied over four orders of magnitude, from quasi-static to near-impulse, were applied to particle systems with and without a pre-compression load. The results of this study and methods described may help in the selection of appropriate modeling parameters for solution stability and accuracy and can guide the determination of physical properties to tailor the local and bulk behavior of a confined particle system.
Post-Processing and Material Properties of Nylon 12 Prepared by Laser-Powder Bed Fusion
Authors: Sperry McKay , Busath Annie , Ottesen Michael , Heslington Jacob , Crane Nathan
Published: January 2022

Laser Powder Bed Fusion (L-PBF) is a fabrication process in the Powder Bed Fusion (PBF) family of additive manufacturing. The key advantage to L-PBF over other manufacturing methods is design flexibility. Additional design flexibility, however, has previously come at the cost of reduced material properties. Polyamide 12 (PA12, Nylon 12) is a semicrystalline polymer with thermophysical properties that make it ideal for L-PBF. Although L-PBF PA12 has tensile strength comparable to injection molded PA12, it has substantially reduced ductility. This paper reports on a series of post-processing treatment for L-PBF of PA12 and measures their impact on strength, ductility, and density. These include annealing, cooling, and pressure treatments. The treatments resulted in PA12 parts with a wide range of properties, which could be tailored according to end-use application with up to 11% increase in strength or 19% increase in ductility.
Effect of Shaking at or Near Resonance of a Simple Head Model on Skull/Brain Connectors
Authors: Daboin Jose , Saboori Parisa
Published: January 2022

A solid model of a six-month-old child has been developed using average human anatomical characteristics combined with crash test dummy dimensions. The model consisted of a body and limbs, and a neck and head combination with the head being hollow and housing a hemispherical brain. This model was then exposed to a linear sinusoidal input displacement to the chest, and the angular displacement of the skull and brain were observed. The resulting data showed that the oscillatory behavior was a function of frequency, and maximal oscillations existed at a frequency close to the expected natural frequency of the head/neck system, and at a frequency one order of magnitude greater than this frequency. In addition, when a square wave was applied, rather than a sine wave, the resulting oscillation proved to be more violent; and finally, a real input was applied to the model, from previous tests, to discover if a different oscillatory behavior resulted.
A Method of Parametric Model Data Exchange and Reconstruction Based on Feature Script
Authors: Ye Peng , Zhang Yonggang , Wang Yanglan , Huang Geying , Guo Lianshui
Published: January 2022

In collaborative product development (CPD), iterative design with heterogeneous CAD systems is always completed by original equipment manufacturers (OEMs) and other suppliers around the world. Therefore, product data exchanges among different heterogeneous CAD systems are crucial in CPD. However, the major bottleneck is that parametric part models of complex products cannot be exchanged among heterogeneous CAD systems. Published by the International Organization for Standardization (ISO), the Standard for the Exchange of Product Model Data (STEP) is the most common solution for geometry-based data exchanges and product annotations in the manufacturing industry. However, the exchanged STEP parts cannot be modified due to the loss of important information including modeling history, parameters and constraints, which involve the design intent. Therefore, the challenge of modification on exchanged parts needs to be overcome for iterative design in heterogeneous CAD systems of the manufacturing industry.

In this paper, a method of part parametric model data exchange and reconstruction based on feature script is proposed. The main idea is features, which include reference features (like datum-plane, datum-axis, and datum-point), shape features (like extrude and rotation), auxiliary features (like fillet and chamfer), and sketch features. These features are taken as the fundamental elements of a part in CAD system, and each is defined by feature script and saved as an extensible markup language (XML) node. The feature modeling history of a part is regarded as a tree structure, which can be converted to an XML tree structure. In part model reconstruction, the proposed method utilizes a persistent naming mechanism and geometric data to identify topological entities, and then realize the persistence of constraint information and parameter driving of part model.

The proposed method will be applied to part data exchange and parametric model reconstruction among heterogeneous CAD systems in the following process: (i) the feature tree and parameters of the parametric model are obtained in the source CAD system; (ii) the feature model data is translated into feature script and saved as XML format file; (iii) the feature script file is read, and the parametric model is reconstructed in the target CAD system according to modeling history. In order to verify the accuracy of data exchange and model reconstruction between Creo and CATIA, a method on constraints equivalence analysis and feature comparison is also proposed for analyzing the similarities and differences between source and target parametric models. In addition, a case study is presented to demonstrate the potentials of the proposed method for parametric-feature model exchanges among heterogeneous CAD systems in web-based collaborative product development.
Educating Historically Black Colleges and Universities Innovators About the Commercialization of Innovation by the Customer Discovery Process
Authors: Addo Sampson , Tyagi Pawan , Shetty Devdas
Published: January 2022

Historically Black Colleges and Universities (HBCUs) innovators lag behind their non-HBCU counterparts in the commercialization of innovations as they were originally set up as teaching and blue-collar trade institutions. There exists a strong need for education and training to bridge this gap by promoting the commercialization of innovations in HBCUs and thus transform next-generation HBCU innovators into entrepreneurs. HBCUs are promoting entrepreneurial education and mindset via changes in engineering education programs and curriculums. Several federally funded programs like the National Science Foundation (NSF) Center of Research Excellence in Science and Technology (CREST) Center for Nanotechnology Research Excellence (CNRE) are promoting innovation and intellectual property generation at HBCUs. NSF I-Corps Program supports the education and training of innovators about the commercialization of mature or patented innovations at HBCUs. The NSF I-Corps Introduction to Customer Discovery explores strategies in identifying key customer segments through extensive customer interviews, which is a fundamental step in the commercialization process. This paper discusses our educational experience in the customer discovery process for Pumpless Solar Thermal Air Heater (Patent Number 10775058). To learn about prospective customers’ attitudes and perceptions of the innovation, we conducted 30 interviews with potential customers (end users). Our innovation is focused on providing portable, cost-effective, healthy, and environmentally friendly space heating solutions. We tested several hypotheses about the value proposition of our innovation during interviews to explore the market segments for potential commercialization. During the Customer Discovery process, we came to know about new issues such as health issues caused by the dry air in winter. We also learned that mitigation of problems due to the current heating system required a humidifier to reduce health issues that added additional cost. Based on our interviews our innovation is suitable for customers needing: (i) Heating source mitigating health issues, (ii) add-on technology to reduce their heating bills. Our next step is to pursue market segments for our innovation. We plan to utilize the current experience of commercialization of intellectual property to develop training modules for the MECH 302 Undergraduate Research Experience and MECH 500 Research Methods and Technical Communication courses offered under the mechanical engineering program at the University of the District of Columbia (UDC).
Digital Twin: Universal User Interface for Online Management of the Manufacturing System
Authors: Kuts Vladimir , Bondarenko Yevhen , Gavriljuk Marietta , Paryshev Andriy , Jegorov Sergei , Pizzagall Simone , Otto Tauno
Published: January 2022

Industry 4.0 concept enables connecting a multitude of equipment to computer simulations through IoT and virtual commissioning, but using conventional interfaces for each separate piece of equipment for control and maintenance of Digital Twins is not always an optimal solution. Industrial Digital Twins software toolkits usually consist of simulation or offline programming tools. It can even connect real machines and controllers and sensors to feed a simulation with actual production data and later analyze it. Moreover, Virtual Reality (VR) and Augmented Reality (AR) are used in different ways for monitoring and design purposes. However, there are many software tools for the simulation and re-programming of robots on the market already, but those are a limited number of software that combine all these features, and all of those send data only in one way, not allowing to re-program machines from the simulations. The related research aims to build a modular framework for designing and deploying Digital Twins of industrial equipment (i.e., robots, manufacturing lines), focusing on online connectivity for monitoring and control. A developed use-case solution enables one to operate the equipment in VR/AR/Personal Computer (PC) and mobile interfaces from any point globally while receiving real-time feedback and state information of the machinery equipment. Gamified multi-platform interfaces allow for more intuitive interactions with Digital Twins, providing a real-scale model of the real device, augmented by spatial UIs, actuated physical elements, and gesture tracking.

The introduced solution can control and simulate any aspect of the production line without limitation of brand or type of the machine and being managed and self-learning independently by exploiting Machine Learning algorithms. Moreover, various interfaces such as PC, mobile, VR, and AR give an unlimited number of options for interactions with your manufacturing shop floor both offline and online. Furthermore, when it comes to manufacturing floor data monitoring, all gathered data is being used for statistical analysis, and in a later phase, predictive maintenance functions are enabled based on it.

However, the research scope is broader; this particular research paper introduces a use-case interface on a mobile platform, monitoring and controlling the production unit of three various industrial- and three various mobile robots, partially supported by data monitoring sensors. The solution is developed using the game engine Unity3D, Robot Operation System (ROS), and MQTT for connectivity. Thus, developed is a universal modular Digital Twin all-in-one software platform for users and operators, enabling full control over the manufacturing system unit.
Experimental Study of Gas-Liquid Mass Transfer in a Rectangular Microchannel by Digital Image Analysis Method
Authors: Yang Shuo , Kong Gaopan , Wu Zan
Published: January 2022

Study of mass transfer in microchannels is indispensable for the design of microreactors. Gas-phase volume monitoring method has been widely used to study the mass transfer process. When using this method, bubble length was measured in most studies to calculate the bubble volume by assuming a symmetrical bubble shape. Therefore, this method is not suitable for asymmetric bubbles. The present study focuses on the mass transfer of CO2 bubbles in a flat rectangular microchannel by using the method of digital image analysis (DIA), especially for deformed bubbles. The dynamics of gas-liquid flow at different volumetric flow rates were observed by a high-speed recording system. Flow patterns were mapped and scaling laws were given for bubble size and bubble velocity. The results showed that the bubble volume increases as gas flow rate increases, while decreases as liquid flow rate increases. It can be explained by the bubble breakup mechanism. Besides, the bubble velocity increases as gas and liquid flow rates increase. The mass transfer of CO2 from bubbles to liquid slugs was quantitatively characterized by volumetric mass transfer coefficient kLa. The results showed that kLa and kL increase with increasing of superficial gas and liquid velocities. The same tendencies can be found in the literature. Finally, new mass transfer correlations were proposed. Predictions from the correlations showed a good agreement with the experimental data.
Measurements of Pulsation Generated Due to Turning Flow Into Side Branches of Different Diameter Ratios
Authors: Botros Kamal K. , Satish Hemanth
Published: January 2022

The present investigation was motivated by a noticeable high-pressure pulsations and vibrations during commissioning of a centrifugal compressor on a high-pressure natural gas transmission system. During commissioning, the gas from the compressor discharge is recycled back to compressor inlet through a recycle line turning the gas flow from the main discharge line into a smaller diameter side branch, thus creating a deadleg due to the closure of a check valve farther downstream on the main discharge line. To better understand and characterize the flow generated pulsations due turning flow into side branches, an experimental setup was constructed on ambient air to test three side-branch to main pipe diameter ratios (d/D), nominally: 1.0, 0.75 and 0.5, over a wide range of mean flow velocities. Experimental results of the normalized pulsation pressure amplitudes (P*) vs. Strouhal number characterized the flow-acoustic field for the three d/D ratios and for acoustically tuned and detuned systems. It was found that P* decreases as d/D decreases for acoustically tuned systems. The highest P* was achieved with d/D = 1 which reached a value of 3.543 at St = 0.1376. At lower d/D = 0.762, the maximum value of P* decreased to 1.173 at a slightly lower St number of approximately 0.1. In the case of d/D = 0.5132, the normalized pressure P* was further reduced to a very low value of 0.2462 at a wider range of St number. Acoustically tuned system is characterized by having the highest anti-nodal point of acoustic velocity oscillation at the Tee-junction location in the axial direction of the main pipe, with minimum acoustic leakage into the side branch. When the system is acoustically detuned, i.e., when the axial acoustic velocity oscillations at the Tee-junction is reduced, the strength of the local acoustic source at the junction is also reduced resulting in a lower peak normalized pressure amplitude at the deadleg. The peak amplitudes of pressure pulsations occur at frequencies exactly matching the deadleg 1/4 wavelength resonance, whether it is tuned or detuned with respect to the inlet section. That is, the peak frequencies tracked the changes in the deadleg length and was not influenced by the inlet section acoustic resonance characteristics. This led to the postulation that the main driver of the flow-generated pulsations, i.e., the acoustic source is associated with the high-shear area of the flow facing the deadleg at the trailing edge of the Tee-junction rather than the ‘vortex bubble’ due to flow separation at the leading edge of the side branch.
A Numerical Hybrid Finite Element Model for Lattice Structures Using 3D/Beam Elements
Authors: Tahmasebimoradi Ahmadali , Mang Chetra , Lorang Xavier
Published: January 2022

In this work, a numerically hybrid model is presented for the lattice structures to reduce the computational cost of the simulations. This approach consists of utilization of solid elements for the junctions and beam elements for the microbeams connecting the corresponding junctions to each other. To take into account the geometric defects, for each microbeam of the lattice structures, an ellipse is fitted to capture the effect of shape variation and roughness. Having the parameters of the ellipses, the lattice structures are constructed in Spaceclaim (ANSYS) using the geometrical hybrid approach. When the global response of the structure is linear, the results from the hybrid models are in good agreement with the ones from the 3D models. However, the hybrid models have difficulty to converge when the effect of large deformation and local plasticity are considerable in the BCCZ structures. For BCCZ lattice structures, the results are not affected by the junction’s size. This is also valid for BCC lattice structures as long as the ratio of the junction’s size to the diameter of the microbeams is greater than 2.
Multilayer Separation Effects on MoS2 Membranes in Water Desalination
Authors: Oviroh Peter Ozaveshe , Oyinbo Sunday Temitope , Karimzadeh Sina , Jen Tien-Chien
Published: January 2022

Climate change and its related effects are imposing severe stress on the current freshwater supplies. This has been exacerbated due to the growth in population, rapid industrialization, and increased energy demand. Increased water requirement is a global challenge. Although more than 70% of the Earth is covered by water, much of it is unusable for human use. Freshwater reservoirs, ponds, and subterranean aquifers account for just 2.5% of the world’s overall freshwater availability. Unfortunately, these water supplies are not very unevenly spread. Therefore, the need to augment these supplies through the desalination of seawater or brackish water.

Reverse osmosis (RO) is currently the most widespread method of desalination. However, the unit cost of water is still high partly due to the thin-film composite (TFC) polymer membranes used in the current desalination system. Thus the need for low-cost nanomaterials for Water Desalination and Purification. A promising way to meet this demand is to use two-dimensional (2D) nanoporous materials such as graphene and MoS2 to minimize energy consumption during the desalination process. New nanotechnology methodologies that apply reverse osmosis have been developed. Among some of these technologies is using 2D materials such as graphene and MoS2, which have been studied extensively for water desalination.

Single-layer nanoporous 2D materials such as graphene and MoS2 promises better filtrations in the water channel. Although single-layer MoS2 (SL_MoS2) membrane have much promise in the RO desalination membrane, multilayer MoS2 are simpler to make and more cost-efficient. Building on the SL_MoS2 membrane knowledge, we have used the molecular dynamics method (MD) to explore the effects of multilayer MoS2 in water desalination. This comparison is made as a function of the pore size, water flow rate and salt rejection. In addition, we also looked at the effect of the increased interlayer spacing between layers of the nanoporous 2D membrane and then made the comparison.

The ions rejection follows the trend trilayer> bilayer> monolayer from results obtained, averaging over all three membrane types studied for the MoS2, the ions rejection follows the trend trilayer > bilayer > monolayer. We find that the thin, narrow layer separation plays a vital role in the successful rejection of salt ions in bilayers and trilayers membranes. These findings will help build and proliferate tunable nanodevices for filtration and other applications.
Probabilistic Optimization Approach for Damage Identification Using Frequency Response
Authors: Altammar Hussain , Kaul Sudhir , Dhingra Anoop
Published: January 2022

This paper presents a novel probabilistic optimization approach to identify damage characteristics by using the frequency response function (FRF). The proposed approach has been developed to predict the probability of damage existence and to further identify salient details about damage location and damage severity in a probabilistic manner. The optimization problem has been developed as a function of measured and simulated frequency responses and is formulated in a multi-stage sequence to detect the probability of damage parameters including crack depth and crack location while minimizing uncertainties in the analysis outcomes. To demonstrate the proposed approach, a simply supported beam has been modeled with an open edge crack and characterized by using Linear Elastic Fracture Mechanics (LEFM). Several frequency responses obtained from the structure have been incorporated with different levels of noise to evaluate the robustness of the proposed algorithm. The algorithm has been tested through multiple simulations with various damage characteristics and different levels of noise. In all cases, the proposed algorithm has successfully predicted the presence of damage with a relatively high probability. Evaluation of the results demonstrates that the probabilistic optimization approach provides significant advantages over conventional deterministic methods for damage detection in structural health monitoring.
Application of Block-Based Programming to the Selected Open-Source Quadrupedal Platform for Improving Robotics Training
Authors: Vollaro Stephen , Wein Mason , Tatoglu Akin , Sohn Kiwon
Published: January 2022

Quadruped robots offer a mechanism with a highly dynamical equation of motion and a complex control system not only to maintain a gait motion but also to control individual torque values at different coordinates. A previously developed open-source quadruped platform was used, slightly modified in mechanical design, and then implemented visual tools that can serve different levels of curriculums and research. Additive manufacturing reduced cost of sensors and actuators enabled rapid prototyping of these complex robots. As a result, it can be used for wide variety of purposes from graduate research to K-12 education. Additionally, it is important for students to be exposed to more complex dynamical systems at an earlier stage of their education. A visual coding suitable for any researcher or student with limited programming skills was developed so they can rapidly start working with the system. While this robot is used in higher education, it also offers a full-scale platform to study control, path and motion planning algorithms with an access to the open-source code. The final product, named Mini-HART, uses two microcontroller units, MCUs, a Raspberry Pi for higher education and an Arduino Mega for the selected Ardublock Visual Programming.
Stability Performance of a Stochastic Toolpath in Machining
Authors: Grimm Tyler J. , Kharat Nilesh Ashok , Potthoff Nils , Mears Laine , Wiederkehr Petra
Published: January 2022

The overall quality and efficiency of a machined part relies heavily on the tool path that is used. A more recently developed toolpath method is known as trochoidal milling, which is also known by several other terms, such as adaptive milling, circular milling, or volume clearing. In order to follow the contours of the final geometry, this path can give rise to a significant number of direction changes, which result in highly variable force directions on the tool. Chatter, or self-excited vibration that occurs at the tool or workpiece, can therefore be mitigated or avoided since periodic resonance does not have time to increase the vibration’s amplitude.

A randomized variation of the trochoidal path is tested in this research. Using this new proposed method, stochastic behavior of the toolpath is implemented. The toolpath consists entirely of circular arcs, which drive the tool in a pseudo-random fashion. The stability of such a path is examined in this work. A key parameter of this path is the allowable radius range of the circular arcs. It was found that the most efficient path utilized a median parameter value, illustrating an overall negative parabolic relationship between path efficiency and tool path radius. It was also discovered that smaller arcs reduced chatter. Future studies will explore the behaviors of this path for milling 3D surfaces.