bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication and Testing of Asymmetric Magnetic-Polymer Flexible Sheets for Biomedical Actuated Devices
Authors: Manzo Maurizio , Bakaraju Megha
Published: February 2023

Flexible actuated sheets are currently being used in different devices in the biomedical field for a variety of different applications. Examples of biomedical devices that use flexible actuated sheets are neural probes, microneedles, micropumps for insulin, intraocular and inner ear drug delivery systems. Among them, micropumps are one of the most flexible and popular devices. In fact, micropumps are being extensively studied for multiple biomedical applications — controlled drug delivery systems, artificial sphincter prosthesis, cell culturing, micro-fluidic analyses. One of the most important applications for actuated membranes is in drug delivery systems, but there are multiple challenges that exist including maintaining controlled flow rate, reaching delicate tissues, and preventing complex side effects.

In this paper, the effect of an inhomogeneous distribution of magnetic particles in the membrane used for actuation is studied for the first time. The fabrication and testing of asymmetric thin flexible sheets magnetic actuators are presented. Focus of this research is to fabricate thin polymeric sheets with thickness range of 120–125μm, with asymmetric distribution of magnetic nano/micro particles.

Iron oxide (Fe3O4) particles are embedded into polymeric membranes made of Polydimethylsiloxane (PDMS). From the perspective of biomedical application, PDMS is chosen for its excellent biocompatibility and Fe3O4 for its non-toxic nature. The particles are mixed with the PDMS polymeric solution and micromagnets are used to localize the magnetic particles during the curing process at selected locations to create asymmetry into the particles’ distribution.

Fe3O4 – PDMS membranes are fabricated and mounted to a fixture to observe deflection by using a camera. An external magnetic field is applied for the actuation of the membrane and two measurement types are made: static and dynamic. A permanent magnet is used for generating the external magnetic field, which is attached to a piezoelectric actuator. The effect of the distribution of magnetic particles are investigated in terms of the deflection of membranes for both static and dynamic behavior. A comparative study of membranes with inhomogeneous and randomly distributed particles is carried out. This work shows that the inhomogeneous distribution of particles has a positive effect on the deflection of the membranes, making them favorable for a wide range of applications involving localized and targeted treatments and precision medicine.

Since magnetic actuation does not require onboard batteries or other power systems, it is very convenient to use. Magnetically actuated sheets can be used in Hyperthermia to have enhanced results due to asymmetric distribution of magnetic particles.
A Domain Specific Language Applied to Phonon Boltzmann Transport for Heat Conduction
Authors: Heisler Eric , Saurav Siddharth , Deshmukh Aadesh , Mazumder Sandip , Sadayappan Ponnuswamy , Sundar Hari
Published: February 2023

The phonon Boltzmann transport equation is a good model for heat transfer in nanometer scale structures such as semiconductor devices. Computational complexity is one of the main challenges in numerically solving this set of potentially thousands of nonlinearly coupled equations. Writing efficient code will involve careful optimization and choosing an effective parallelization strategy, requiring expertise in high performance computing, mathematical methods, and thermal physics. To address this challenge, we present the domain specific language and code generation software Finch. This language allows a domain scientist to enter the equations in a simple format, provide only basic mathematical functions used in the model, and generate efficient parallel code. Even very complex systems of equations such as phonon Boltzmann transport can be entered in a very simple, intuitive way. A feature of the framework is flexibility in numerical methods, computing environments, parallel strategies, and other aspects of the generated code. We demonstrate Finch on this problem using a variety of parallel strategies and model configurations to demonstrate the flexibility and ease of use.
A Study on the Effect of Graphene on the Vibrational and Flame Retardant Characteristics of the GFRP Composites
Authors: Nagamalai Thangapandian , Shanmugam Ragavanantham , Murugan Thirumal Azhagan , Vinayagam Mohanavel , Dennison Seth
Published: February 2023

In this work, the graphene nanoplatelets were reinforced in the GFRP composites to improve their mechanical, vibrational, and flame retardant properties. Three nanocomposites plates namely G1 (GFRP+0.25 wt.% graphene), G2 (GFRP+0.5 wt.% graphene), G3 (GFRP+1 wt.% graphene), and a neat composite plate (G0) were fabricated using hand layup method followed by compression molding. The effect of graphene on the damping properties of the composites was studied by using a free vibration test. The reduction in natural frequency was witnessed in the nanocomposite material ensuring the effective interfacial bonding between the graphene and matrix. The rate of burning test results confirms that the addition of graphene resulted in improved flame retardancy due to the formation of a protective char layer. The highest tensile strength value was observed in the 0.5 wt.% graphene composites, which is ∼1.5 times higher than that of the neat composites. The strength reduction in 1 wt.% graphene composites is due to the percolation of graphene, which acts as a potential site for stress concentration. Unlike tensile strength, the shore hardness value increased with the wt.% of the graphene reinforcement. This study elaborates the synergetic effect of graphene on the mechanical and vibrational characteristics of the composites.
Computational Modeling of Multi-Pass Rolling Parameters Effect on Resulting Fuel Foil Shape
Authors: Mason Taylor , Choi Kyoo Sil , Soulami Ayoub , Johnson Kenneth , Brooks Kriston , Karri Naveen , Joshi Vineet
Published: February 2023

A focus of the U.S. Department of Energy is to improve production yield and reduce the cost of Low Enriched Uranium (LEU)-molybdenum alloy (U-10Mo) monolithic fuel plates that will be replacing High Enriched Uranium (HEU) oxide dispersion fuels used currently in the United States High Performance Research Reactors (USHPRR). One area of improvement is lowering the transverse waviness and longitudinal waviness that can be present within the cold rolled foils following rolling operations. Traditional rolling manufacturing techniques for other metal foils use winders to pull and straighten the foil as it is rolled back and forth to the final thickness. This approach cannot be used to roll thin U-10Mo foils (0.008–0.025″ thick) because only small castings can be rolled due to nuclear criticality safety concerns. As a result, the fuel foils are too short (∼1–2 m in length) to use traditional winders. Therefore, it is crucial to identify other rolling parameters (i.e., roller friction, axial tension load, roller diameter, and roll pass reduction percent) that might reduce transverse waviness and longitudinal waviness in the rolled fuel foil and develop a high-yield, low-cost multi-pass rolling manufacturing process. This report documents a systematic finite element modeling study to investigate the effects of numerous rolling parameters to reduce resulting transverse waviness and longitudinal waviness in the fuel foil during multi-pass rolling of U-10Mo foils. The rolling of a U-10Mo plate with initial dimensions of 1″ × 1″ × 0.048″ is modeled using Abaqus CAE. This rolling is modeled to undergo eight 20% reduction roll passes to a final fuel foil thickness of 0.01″. The elastic-plastic constitutive model of the U-10Mo alloy was input to the fuel foil rolling model. The rollers were modeled as rigid bodies. A comparison of rolling friction coefficients of 0.3 and 0.7 over a wide range of applied axial tension loads were investigated in order to evaluate the effect of using a lubricant during rolling. The effect of roller diameter on the resulting transverse waviness and longitudinal waviness of the fuel foil over a wide range of axial tension loads were also investigated by modeling rollers 7/8″ and 3.75″ in diameter. The results of this systematic finite element method study will aid manufacturers in producing low transverse waviness and reduced longitudinal waviness in U-10Mo fuel foils.
Optimization of Supercritical CO2 Cycle Combined With ORC for Waste Heat Recovery
Authors: Carapellucci Roberto , Di Battista Davide
Published: February 2023

Waste heat recovery is a broadly considered opportunity for efficiency improvement in several energy consumption sectors, intending to reduce energy consumption and related carbon dioxide emissions to the atmosphere. The attention of research activities is focused on transportation and residential sectors, where the possible recovery is characterized by low enthalpy, but with a wider potential market. Therefore, the maximization of recovery is one of the principal aims of this option, and different kinds of technologies have been proposed in this regard. Thermodynamic cycles, which exploit the waste heat considering it as the upper thermal source, seem to be a promising option, and the possibility to combine two different cycles can increase the thermal power harvested.

In this paper, a combination of a supercritical CO2 Brayton cycle with an ORC-based unit has been proposed to recover waste heat from the exhaust gases of an internal combustion engine for the transportation sector. Using CO2 as working fluid is under investigation in literature, for its low Global Warming Potential and its suitable thermodynamic characteristics in dense phase (just above the critical point). An Organic Rankine Cycle (ORC), then, has been bottomed to the CO2 section, to further recover thermal energy and convert it into mechanical useful work. Indeed, the CO2 cycle must have a lower temperature cold sink, where thermal power can be furtherly recovered. The introduction of this second stage of recovery interacts with the upper one, modifying the overall optimization parameters. Hence, this work aims to find the maximization of the recovery from a global point-of-view, identifying possible trade-offs happenings between the two recovery sections. Minimum sCO2 pressure, stack exhaust temperature, and the possibility to have a regeneration stage have been considered as optimizing parameters.

Finally, the optimized system has been applied to a specific mission profile of a commercial vehicle, in order to evaluate the recovery potential during a realistic engine working points sequence. A recovery higher than 4% in every mission considered has been achieved, with values up to 7% in motorway and long-hauling conditions.
Modeling Single Ventricle Morphology With a HLHS-Specific Biventricular Template to Enhance Statistical Shape and Biomechanics Analyses
Authors: Tang Renxiang , Govil Sachin , Mauger Charlène , Hegde Sanjeet , Omens Jeffrey H. , Perry James C. , McCulloch Andrew D.
Published: February 2023

Modeling the hearts of patients with hypoplastic left heart syndrome has remained an ongoing challenge. Thus, in this work, we developed a HLHS-specific biventricular template to capture the single ventricle morphology in this cohort accurately and robustly. We have demonstrated that using the HLHS-specific template to reconstruct patient-specific models from cardiac magnetic resonance images result in significantly higher accuracy comparing to that of using the generic template. Additionally, element distortion in meshes created using the HLHS-specific template is compatible with meshes currently used for finite element analysis. Accurate 3D patient-specific models will serve as powerful tools for subsequent statistical shape and biomechanics analyses to provide insights into remodeling of ventricular shape and function and their potential association with clinical outcomes.
Effects of Flow-Induced Vibration on Forced Convection Heat Transfer From Three Tandem Cylinders at Different Spacing Ratios
Authors: Khan Hamid , Islam Md.
Published: February 2023

This work numerically investigates the effect of FIV on the heat transfer performance of three heated tandem cylinders at different spacing ratios and reduced velocity. The simulation is performed at Reynolds number Re = 100, Prandtl number Pr = 0.7. The three elastically mounted heated cylinders are allowed to oscillate in the transverse direction with reduced velocity Ur = 2–20, mass ratio m* = 2, and zero damping coefficient for maximum oscillation. The spacing ratio between cylinders G* = 2 and 4 are considered to elucidate the effect of FIV on heat transfer in extended body regime (G* = 2) and reattachment regime (G* = 4). The effect of the spacing ratio on FIV and heat transfer is observed through flow structures and quantified through oscillation amplitude, shedding frequency, pressure coefficient, and Nusselt number. The flow around the cylinders and the associated heat transfer depend strongly on the spacing ratio. The present findings can be utilized to develop a strategy for reducing fouling and removing contaminants and wax in piggyback pipes used in nuclear power plants or offshore oil extraction.
Operational Performance of a Photonic Based Microcalorimeter: Specific Heat Measurement
Authors: Zhang Yuwei , Kowalski Gregory
Published: February 2023

A photonic-based nanohole array sensor microcalorimetry is developed at the Microfluidic laboratory at Northeastern University utilizing changes in the extraordinary optical transmission (EOT). This experiment utilized calorimetry to conduct a novel specific heat measurement method for non-reacting fluids on the microscale level. This paper describes a calibration process and an accuracy test for this novel calorimetry. The test chamber was prefilled with deionized (DI) water (55 μl) and heated to steady state. Then room temperature DI water (15 μl) was injected and was treated as an unknown material. The temperature time history is recorded by the thermistor data acquisition system and the EOT by a CCD camera. An energy balance equation and algorithm were developed to calculate the specific heat of the injected material which was compared with its known value. The observed EOT and the corresponding temperature calculated from it exhibit the same trends. The error between the measured and known specific heat specific is 2–6%. The calorimetry has a significantly faster thermal response than traditional calorimeters and requires less compound with high accuracy.
On the Efficacy of Non-Holonomic Canonical Momentum Analysis of Constrained Multi-Body Mechanical Systems – Application in Ground Vehicle Double Wishbone Suspension Dynamics
Authors: Olorunfemi Oluwaseyi J. , Barhorst Alan A.
Published: February 2023

In this research, we aim to ascertain the practicability of generalized momentum canonical equations for non-holonomic rigid body systems by applying it to the modeling and simulation of a Double Wishbone suspension system dynamics. The model of the Double Wishbone suspension system of a passenger car’s front drive is assumed to be planar, with four degrees of freedom. Equations of motion derived from the model are solved using Wolfram Mathematica’s NDsolve Algorithm while dynamic simulations are made from modeling a real-life scenario and verification of the model. Simulated real life scenario had the model excited in one of the four DOFs — the roll rate of the model. Therefore simulation results, graphical plots of the total energy, constraint loop and generalized parameters of the DWB suspension system, predicted the response of vehicle dynamics in this event for a period. The method provides accurate results and we can infer that the set of equations of motion formulated from the projective momentum method can accurately simulate the inherent nonlinear vehicle suspension dynamics behavior. Therefore, the generalized momentum canonical equation for constrained systems has the capability to be used for vehicle dynamics analysis and prediction that are necessary for understanding the complexities involved in ground vehicle ride and handling.
Energy Consumption Evaluation on Robotic Drilling Process Using Digital Twin Technology
Authors: Cardoso Matheus , Lozan Rodrigo , Barbosa Gustavo , Guerra-Zubiaga David , Shiki Sidney
Published: February 2023

Faced with the advances in automation related to the digital transformation of the industry, new products are developed, and the fabrication processes are becoming smarter day by day. However, modern manufacturing systems look for electricity savings, especially in machining operations. In this sense, power consumption has a big deal for industry costs, and it needs to be monitored to provide a more competitive business. So, to minimize this problem, digital manufacturing based on simulation tools has been used to find economic ways to optimize the manufacturing processes, providing a reduction of recurring costs. Thus, this research proposes the use of Tecnomatix Siemens PS (Process Simulate) software for process simulation of 2024 aluminum drilling to explore the analysis of energy consumption (EC) in a machining operation using a robot. Also, this proposal looks for a digital twin conception, comprising its variables and features to make possible a case study assisted by the Design of Experiments (DOE) method.
Design of a Clutching and Braking System to Automate a Chain-Coupled Dual Planetary Gearing Transmission
Authors: Cann Megan , Speed Robert , Moreno Abraham , Azzouz Salim
Published: February 2023

The engineering team at Midwestern State University is working on a double planetary gearing transmission coupled by driving chains and sprockets. The ultimate purpose of this project is to manufacture and automate a transmission apparatus for the Machine Element Design Laboratory. The current team is the fourth team to work on this project and is tasked to build a better entry and exit shaft, as well as a braking system, and automate the entire system.

The Willis Gearing Theory was used to determine the system’s theoretical gear ratios. Next, the entry and exit shafts of the transmission, as well as the braking system, were designed using the SolidWorks CAD software. The blueprints were then sent out to a machine shop for manufacturing and then assembled. A programmable logic controller activated two linear actuators to move two keyed shafts at the entry and the exit of the transmission. An Arduino board was used to ensure safe placement of the braking blocks. It is expected that a future team will complete the PLC programming, measure the mechanical advantage of the system to compare to the theoretical velocity ratio, determine the efficiency of the transmission, and create a lab manual.
Simulation and Parametric Studies of a Linear Fresnel Solar Concentrator Using Air As HTF for Agricultural Drying Applications
Authors: Jaramillo-Cobos Daniela , Delgado Plaza Emerita , Durazno-Palacios Galo , Peralta-Jaramillo Juan
Published: February 2023

To ensure long-term energetic security and stability, it is necessary to work and develop in diversification, availability, profitability, and accessibility to several energy sources, which can be directly applied to all strategic sectors of the society, for example, the agricultural sector. Solar concentrators are devices designed to harness solar energy and convert the solar radiation into heat that can be used by solar dryers. The solar dryer is a technology that can be easily deployed and adopted in rural areas due to its energy efficiency and minimal environmental footprint.

This paper develops a simulation model and parametric studies of a linear-Fresnel-solar-concentrator using air as HTF for agricultural drying applications, specifically to dry mango in Guayaquil, Ecuador. Parametric analyses are performed to evaluate the thermal behavior of the linear-Fresnel-concentrator based in inlet-solar-radiation, the number of primary reflective mirrors, length of the receptive cavity and HTF mass-flux. These studies have shown that the model reaches an equilibrium point with 14 primary reflective mirrors with a length of 7 meters each. Additionally, when there is a flux increase in the HTF, a linear correlation between mass-flux and temperature appears, and for inlet-solar-radiation there is a quadratic correlation.
Research on Coarse Granularity Data Sample Completion Method for District Heating System
Authors: Luo Zheng , Feng Encheng , Lin Xiaojie , Zhong Wei
Published: February 2023

The heating system is an essential part of China’s urban energy system. However, the heating systems in China have varying levels of hardware and software, informationization, and intelligence. The coarse time granularity of actual system data and the missing data brings significant challenges to system analysis and diagnosis. This paper proposes to study the sample completion and granularity refinement of the time-series data of heating systems based on Wasserstein Generative Adversarial Networks (WGAN). The method is validated based on the field data from 2019 to 2020 of a district heating system in Zhengzhou. Besides, the key features affecting the quality of the completion are discussed. After introducing the data processing method of Empirical Modal Decomposition (EMD), the results show that historical data and climate data dominate the quality of the generated samples. The WGAN can generate the samples accurately. When comparing the real data under the same conditions, the accuracy rate reaches 96.4%. This study further refines the sampling granularity of the existing heating system based on the WGAN to provide more accurate samples for system analysis and diagnosis. Overall, the study provides a new data analysis method for theoretical and technical studies under data deficiency scenarios for heating systems.
Techniques for High-Speed Measurement of Accelerating Flame
Authors: Shaffer James , Askari Omid
Published: February 2023

Measurement of time resolved velocities with large accelerations is challenging because the optimal capture rate and pixel resolution changes with velocity. It is known for velocity measurements that high temporal resolution and low pixel resolution increases the velocity uncertainty. This makes selecting acceptable camera settings unintuitive and can result in highly uncertain measurements. For experimental conditions with slow velocities (< 10 m/s) where high temporal resolution is required (because of rapid acceleration) there arises a need for exponentially increasing pixel resolution to minimize experimental uncertainty which is often impossible to achieve experimentally. Desired measurements for early flame propagation have velocities which span a wide range of velocity which can be greater than 10 m/s during ignition and can drop to under 1 m/s depending on the pressure. This rapid velocity change all usually occurs within a millisecond timeframe.

Typical camera-based velocity measurement usually observes either fast- or slow-moving objects with either an average velocity or a velocity at a single time. The goal of this work is to accurately measure such a rapidly changing experimental condition using camera-based measurement and understand the affect various processing methods have on the result. A practical method is presented here to quantify the noise and observe any induced errors from improper processing where measurable physical analogs are used to represent future experimental conditions. These experimental analogs are in the form of rotating disks which have known radial and velocity profiles that will enable the assessment of experimental parameters and postprocessing techniques. Parameters considered include pixel resolution, framerate, and smoothing techniques such as moving average, Whittaker, and Savitzky-Golay filters.
A Device for Reducing Pressure Ulcers in Bedridden Patients Using Fiber Reinforced Elastomeric Enclosures (FREEs)
Authors: Russo Lea , Gondhalekar Mihir , Kota Sridhar , Bassin Benjamin
Published: February 2023

This paper describes the design, development, and prototype testing of a device that can relieve contact pressure to potentially prevent pressure ulcers in bedridden patients by utilizing pneumatically actuated Fiber-Reinforced Elastomeric Enclosures (FREEs) [1,2].

Bedsores, or pressure ulcers, develop in bedridden patients due to constant contact pressure between a patient’s skin and an external (bed) surface. It is estimated that over 2.5 million patients [8] suffer from pressure ulcer developments annually in the United States. High pressure areas of the body include the sacrum and heel, with 36% of pressure ulcers occurring at the sacrum and 30% occurring at the heel. All other body areas each account for only 6% of pressure ulcer occurrence [6]. They are a major concern for low-mobility, patients who are bedridden for an extended periods and are associated with a 5x increase in patient mortality [3]. In addition, pressure ulcers place a significant cost burden on patients. Development of Stage 4 pressure ulcers and associated comorbidities can cost on average $127,000 to the patient [4]. This high cost is mainly due to attending caregiver’s time.

The most common solution for preventing the development of pressure ulcers in bed ridden hospital patients is for the attending nurses to reposition the patients every 2 hours so that the affected areas are relieved of any contact pressure. Repositioning patients is time consuming and strenuous for health care providers. General purpose “dynamic” pressure relief mattresses have shown to be somewhat effective in reducing the development of pressure ulcers. However, they do not effectively target high pressure areas and still necessitate frequent repositioning.

FREEs can be designed to generate a variety of shapes and motions once actuated (pressurized) and serve as building blocks for soft robotic applications. When FREEs, arranged in parallel, are embedded in a material with compatible elastic properties they propagate their deformed shape throughout the surface. These compliant sheets of FREEs are capable of sustaining loads while relieving pressure on high pressure areas of the body. The prototype for the device presented in this paper was designed for relieving pressure on a patient’s heel area. Preliminary test results demonstrate that the prototype device is effective at lifting a patient’s ankle, for patients weighing up to 250lbs, thus relieving contact pressure. The research also demonstrates the viability of developing modular pressure-relieving pads embedded with more advanced FREEs than described in this paper that can be tailored to relieve contact pressure on other affected areas such as the sacrum.
Fuzzy Logic Based Fusion of 2D LIDAR and Depth Camera Data for Robust Perception of Obstacle Distance
Authors: Saksena Harsh , Anwar Sohel
Published: February 2023

Obstacle detection, avoidance and path finding for autonomous vehicles requires precise information of the vehicle’s environment for accurate navigation and decision making. As such vision and depth perception sensors have become an increasingly integral part of autonomous vehicle research and development work. The advancements made in vision sensors such as radars, Light Detection And Ranging (LIDAR) sensors and compact high resolution cameras is encouraging, however individual sensors can be prone to error/misinformation due to environmental factors such as scene illumination, object reflectivity, and object transparency. The application of sensor fusion in a given system, by the utilization of multiple sensors perceiving similar or relatable information over a network, is implemented to provide a more robust and complete system information and minimize the overall perceived error of the system. The primary objective of this work is to implement a smart and robust sensor fusion system using 2D LIDAR and a stereo depth camera to capture depth and color information of an environment. The depth points generated by the LIDAR are fused with the depth map generated by the stereo camera by a Fuzzy system that implements smart fusion and corrects any gaps in the depth information of the stereo camera. The results show that the output of the proposed fuzzy fusion algorithm provides a higher depth confidence than each of the individual sensors can provide.
A Bio-Printing Strategy to Fabricate Geometrically Accurate 3d Scaffolds
Authors: Quigley Connor , Tuladhar Slesha , Habib Md Ahasan
Published: February 2023

3D bioprinting is a promising field in regenerating patient-specific tissues and organs due to its inherent capability of releasing biocompatible materials encapsulating living cells in a predefined location. Due to the diverse characteristics of tissues and organs in terms of microstructures and cell types, a multi-nozzle extrusion-based 3D bioprinting system has gained popularity. The investigations on interactions between various biomaterials and cell-to-material can provide relevant information about the scaffold geometry, cell viability, and proliferation. Natural hydrogels are frequently used in bioprinting materials because of their high-water content and biocompatibility. However, the dominance of liquid characteristics of only-hydrogel materials makes the printing process challenging. Polycaprolactone (PCL) is the most frequently used synthetic biopolymer. It can provide mechanical integrity to achieve dimensionally accurate fabricated scaffolds, especially for hard tissues such as bone and cartilage scaffolds. In this paper, we explored various multi-material bioprinting strategies with our recently proposed bio-inks and PCL intending to achieve dimensional accuracy and mechanical aspects. Various strategies were followed to co-print natural and synthetic biopolymers and interactions were analyzed between them. The dependence of scaffold geometry on the printing process parameters of synthetic polymer and the rheological properties of natural polymers were identified. The successful application of this research can help achieve dimensionally accurate scaffolds.
Numerical Methods for Heat Transfer Computations of Curved Surfaces Using Excel Techniques
Authors: Abdelmessih Amanie
Published: February 2023

The majority of engineers, at some point of their careers, will employ analysis and modeling to a certain degree of complexity. Excel is installed on most engineers’ personal computers. Usually, engineers are competent in using Excel as a spreadsheet to speed up calculations, and are skilled in creating charts with Excel, but very few engineers can use Excel for Numerical Analysis and simulations. Excel is inexpensive unlike the numerous commercial thermal analysis software available in the market. Consequently, small companies and private consultants can find using Excel for basic simulations attractive.

The author published an article in which three Heat Transfer Numerical cases using Microsoft Excel are discussed in detail [1]. Unfortunately, the three cases only address rectangular cross sections. The rectangular cases are easy to address since Excel elements are square. In engineering practice, many circular cross sections are encountered such as cylinders, pipes, rods, etc. In this article four Numerical Heat Transfer practical cases for circular cross sections using Microsoft Excel are introduced and discussed. Each case is solved with two different Excel methods and results are compared with analysis from Patran Thermal. The first case is a pipe with both internal and external surfaces are subjected to isothermal boundary conditions. The second case is a pipe insulated on the outside and isothermal boundary condition on the inside surface. The third case demonstrates the implementation of uniform heat flux to the exterior surface and convection on the interior surface. Finally, the last case is transient conduction with isothermal boundary conditions on both internal and external surfaces of the tube. The details of the simulations and results are discussed in this article.
Bactericidal Effects of Micropillars: A Molecular Dynamics Study
Authors: Singh Akash , Li Yumeng
Published: February 2023

Previous studies have shown that cicada wings has the ability to kill the bacteria on contact. Study of natural bactericidal surface in cicada wings has opened new dimensions of scientific research in bio-inspired chemical-free bactericidal surfaces. To develop and design such biomimetic bactericidal surface, it is necessary to understand the mechanical bactericidal effects of nanopillars in the presence of bacteria, which is extremely challenging due to the small relevant length and time scales. In this study, we have conducted molecular dynamics (MD) simulations to investigate the biomimetic surface with various nanopillars configurations. MD simulations is an exceptional method to simulate materials with small time and length scales with good accuracy and low computational costs. We have simulated the bacteria’s model using coarse-grained modelling and conducting MD simulations. Effects of nanopillar spacing, diameter and height on the lysis process is studied in this article. It is expected that this study will provide us insights on designing nanopillars in terms of height, spacing and diameter for optimal bactericidal effects that can help in the development of chemical-free antibacterial surface.
Acoustic Emission Detection of Circumferential UV-Mechanical Failure of Glass Epoxy Composites
Authors: Yuan Yilin , Shen Gongtian , Xie Fei , Zhang Junjiao , Gan Pengcheng , Shen Yongna , Su Kuan
Published: February 2023

It is a challenging task to understand the damage and failure of ring glass-epoxy composites after ultraviolet aging in practical application. In this paper, acoustic emission (AE) and X-ray computed tomography techniques are employed to study its damage and failure behavior under circumferential tensile loading. The results show that the additional bending effect can’t be overcome when the specimen is stretched, so the strength test is only an apparent result. With the increase of aging time, the number of AE events gradually decreases, but the accumulated acoustic energy increases, which indicates that the longer the aging time, the more severe the damage during loading. The distribution of failure modes caused by circumferential mechanical properties test of specimens can be characterized by X-ray computed technology. In addition, the two complementary nondestructive testing techniques can effectively monitor the damage process inside and outside the specimen, which can provide the basis for the health monitoring of composite structures.
Digital Twin Simulations Based Reinforcement Learning for Navigation and Control of a Wheel-on-Leg Mobile Robot
Authors: Alsaleh Saleh , Tepljakov Aleksei , Tamre Mart , Kuts Vladimir , Petlenkov Eduard
Published: February 2023

Hybrid mobile robots are able to function in a number of different modes of locomotion, which increases their capacity to overcome challenges and makes them appropriate for a wide range of applications. To be able to develop navigation techniques that make use of these improved capabilities, one must first have a solid grasp of the constraints imposed by each of those different modalities of locomotion. In this paper, we present a data-driven approach for evaluating the robots’ locomotion modes. To do this, we formalize the problem as a reinforcement learning task that is applied to a digital twin simulation of the mobile robot. The proposed method is demonstrated through the use of a case study that examines the capabilities of hybrid wheel-on-leg robot locomotion modes in terms of speed, slope ascent, and step obstacle climbing. First, a comprehensive explanation of the process of creating the digital twin of the mobile robot through the use of the Unity gaming engine is presented. Second, a description of the construction of three test environments is provided so that the aforementioned capabilities of the robot can be evaluated. In the end, Reinforcement Learning is used to evaluate the two types of locomotion that the mobile robot can utilize in each of these different environments. Corresponding simulations are conducted in the virtual environment and the results are analyzed.
Design of Human-Robot Collaborative Workstation for the Packaging of Kitchen Furniture
Authors: Ciccarelli Marianna , Moschini Simir , Palpacelli Matteo Claudio , Papetti Alessandra , Germani Michele
Published: February 2023

Collaborative robotics is a key pillar of the smart factory of the future making production systems more flexible and responsive. To this aim, the research communities have made considerable efforts to enable direct interaction between humans and robots in a safe and integrated shared workspace. However, the industrial sector still shows a mismatch between the HRC potentialities and the HRC existing applications. The design is often technology-driven, and coexistence prevails on cooperation or collaboration. Through the case study, this article describes the human-driven design approach that a company should follow to define and evaluate different scenarios and choose the one that best suits its context and workforce. It considers safety, ergonomic, technical, spatial, and equipment issues. It presents an application common to all sectors, the packaging, addressing the complexities of the new production paradigm of mass customization. The design approach has been tested by the major Italian kitchen manufacturer and the resulting collaborative workstation has been simulated by using the software Tecnomatix Process Simulate. The simulation allowed the analysis and evaluation of risks, layout, and performance. The simulation results showed significant benefits in terms of efficiency ensuring a safe collaboration.
Modeling the Burning of Polymer Matrix: Training Collocation Physics-Informed Neural Network
Authors: Ghaderi Aref , Dargazany Roozbeh
Published: February 2023

The combined impacts of thermal, chemical, and physical processes play a significant role in the pyrolysis problems in polymeric materials. Thermal energy is transported into the material via thermal convection when the charring materials are subjected to high-temperature loading. Decomposition of the resin will result in pyrolytic gases and solid leftovers. The material can be split into three zones based on the degree of pyrolysis of the material: (i) charring zone, in which the material entirely decomposes; (ii) pyrolysis zone, in which the material is disintegrating; and (iii) virgin material zone, in which the material has not yet begun to decompose. Physics-informed neural networks (PINNs) are neural networks whose components contain model equations, such as partial differential equations (PDEs). A multi-task learning approach has emerged in which a NN must fit observed data while decreasing a PDE residual. This article introduces PINN architectures to forecast temperature distributions and the degree of burning of a pyrolysis problem in a one-dimensional (1D) and two-dimensional (2D) rectangular domain. The complex, non-convex multi-objective loss function presents substantial obstacles for forward problems in training PINNs. We discovered that adding several differential relations to the loss function causes an unstable optimization issue, which may lead to convergence to the trivial null solution or significant deviation of the solution. To address this problem, the dimensionless form of the coupled governing equations that we find most beneficial to the optimizer is used. The numerical results are compared with results obtained from PINN to show the performance of the solution. Our research is the first to explore fully coupled temperature-degree-of-burning relationships in pyrolysis problems. Unlike classical numerical methods, the proposed PINN does not depend on domain discretization. In addition to these characteristics, the proposed PINN achieves good accuracy in predicting solution variables, which makes it a candidate to be utilized for surrogate modeling of pyrolysis problems. In summary, the pyrolysis model of materials is solved with the PINN framework; We assumed that all thermal properties of a material (thermal conductivity, specific heat, and density) are affected by temperature and degree of burning. While the achieved results are close to our expectations, it should be noted that training PINNs is time-consuming. We relate the training challenge to the multi-objective optimization issue and the application of a first-order optimization algorithm, as reported by others. Given the difficulties encountered and overcome in this work for the forward problem, the next step is to use PINNs to inverse burning situations.
Sliding Mode Control of a Quad-Copter for Autonomous Trajectory Tracking
Authors: Wood Daniel , Selekwa Majura F.
Published: February 2023

Unmanned air vehicles or drones have become ubiquitous in our daily lives; they are deployed in performing many tasks from dangerous military missions to simple recreation activities. One air vehicle that has become very popular is the quad-copter driven by four vertical and parallel propellers. Today quad-copters are deployed in many video recording and remote monitoring almost everywhere in the world. One area of interest for quad-copters has been in farming operations; these vehicles are used in farming operations for not only aerial monitoring of soil nitrogen levels but many other farm monitoring operations. One common aspect of most quad-copters is that they are teleoperated by the user, i.e., most of them are not yet fully autonomous. There must be a remote pilot who is connected to the quad-copter by a video link so that he/she can control the maneuver of the vehicle along the intended path. This paper intends to show that a quad-copter can be programmed to run autonomously along a predetermined trajectory by using sliding mode control strategy. Since trajectories in most farms are clearly well known in advance, then they can be programmed into the controller for the quad-copter to autonomously track. The design process involves using the intended trajectory to define the 3-D sliding surface and then letting the quad-copter controller switch about that surface while keeping the vehicle in the target trajectory. The workspace is defined as a 3-D space where the sliding surface is defined by fitting weighted spline functions on the coordinates of the intended trajectory to define the stable sliding surface whose stability lever increases as the vehicle moves towards the target point. Preliminary results compare the trajectories followed by the quad-copter and the intended trajectories by using the mean square deviation. As would be expected, the performance depends heavily on the speed of the quad-copter; higher speeds on sharp curvature are associated with large tracking errors than low speeds on similar curvatures, while the performance on straight line paths was considerably good. This is most likely due to the switching speed because it seems that higher speeds should be associated with higher switching speeds also. The future work intends to study if parameterizing the 3-D splines using speed and time can improve the tracking performance where the switching rate will be made to be proportional to the number of spline functions that define the trajectory irrespective of the speed of the quad-copter.
Stochastic Analysis of the Carbon Nanotube Network Interphase in Dry and Pre-Infused Buckypaper
Authors: Yekani Fard Masoud , Perrino Samuel , Hedman Conor
Published: February 2023

Assembling CNTs into a thin film Buckypaper (BP) effectively creates high CNT content nanocomposites. BP consists of entangled CNT networks with a porous 3D structure in which CNTs are randomly distributed. The interaction between the dispersed CNT and the polymer or between the CNT network and the surrounding polymer occurs via interphase. The interphase is the region between two constituents and has different local morphology and properties than the constituents. The morphology and properties of the interphase between the CNT network and polymer have not been given enough attention in the literature. Atomic Force Microscopy-based Peak Force Quantitative Nanomechanics Mapping (PFQNM) technique has been used to characterize the CNT network interphase at the nanoscale with high lateral resolution. Probe actual stiffness, tip radius, tapping force, deformation level, and deflection sensitivity for heterogeneous BP are discussed. The nano-scale material properties are extracted from the DMT contact mechanic’s model. The authors show that reduced modulus and deformation can examine the interphase zone thickness and properties. Weibull model is used to investigate the distribution of an interphase thickness and the size of the CNT network.
Hybrid Manufacturing Decomposition Rules and Programming Strategies for Service Parts
Authors: Urbanic Ruth Jill , Hedrick Bob , Ramezani Hamoon , El Moghazi Sandy , Saghafi Marzie
Published: February 2023

For service parts, production runs are ‘on demand’, and managing the inventory for components or the tooling is expensive. Additive manufacturing (AM) processes lend themselves to this application as their key strength is the ability to fabricate components with no tooling or fixtures. However, several AM processes require significant post processing to remove support materials as well as generate the required surface finishes and feature tolerances. The main purpose of this research is to determine whether a directed energy deposition (DED) AM solution can be used to manufacture selected components that are presently cast, machined, or forged using hybrid manufacturing build solutions, where machining operations are introduced as required. Select DED AM processes are used to fabricate a near net shape, and either final machining or interspersed machining operations are included. A product-process classification schema is introduced to cluster similar build strategies. This provides the background for the decomposition approaches and the process planning strategies. The build times and material usage are included and component redesign is discussed to facilitate the manufacturing process and optimize the design. This is ongoing research and, in future work, an analysis of the heat maps and the resulting mechanical and physical properties will be evaluated for these components.
Effects of the CNT Network Size and Interphase on Mode I Fracture of Buckypaper Nanocomposites
Authors: Yekani Fard Masoud , Raman Rohan , Orozco Yesenia , Tata Aditi
Published: February 2023

Buckypaper (BP) is a complex 3D CNT structure with randomly distributed CNTs. The size of the CNT network and interphase can potentially affect the fracture behavior of BP nanocomposite on a larger length scale. For multiwall carbon nanotube BP, the main pore sizes range between 20–35 nm (intrabundle) and 65–110 nm (inter bundle). Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) have proven nano and sub-micron inhomogeneities in BP membranes. These inhomogeneities affect the macroscale mechanical response of BP membranes due to the local high modulus mismatch among CNT particles, the CNT networks, and the polymer. The geometry (shape and size) and the spatial locations (depth and distance between the networks) of the buried CNT networks are amongst critical parameters for the degree of the mechanical mismatch. Atomic Force Microscopy-based Peak Force Quantitative Nanomechanics Mapping (PFQNM) technique is used to quantify the nano- and micro-properties of CNT networks and interphase. Double Cantilever Beam (DCB) specimens are used for mode I fracture characterization. The compliance Calibration technique is used to calculate the initiation and propagation energy release rate. The authors use the Weibull model to examine material properties’ statistical distribution. Weibull statistics link the probability of an event such as CNT network size and interphase thickness.