bluuebunny/crossref_metadata_2025 huggingface dataset:
Atmospheric Water Capture Potential in Arid Countries: An Experimental Investigation
Authors: Rashad Muhammad I. , Mourad Nada , Mubarak Abdallah , Faiad Hend A. , Ahmed Shehab , Farahat Mohamed A.
Published: February 2024

The decline in freshwater supply is a multifaceted global problem that affects both developing and developed countries. In the MENA region, groundwater reserves are overexploited, leading to a heavy reliance on desalination as a main source of drinkable water. However, desalination requires high capital investment and adequate infrastructure. Lack of proper infrastructure further delays implementation of large-scale desalination plants, posing threats to economic growth, social development, and public health, particularly in developing countries. One potential solution in regions with high humidity and temperatures is atmospheric water generation (AWG), which can be used in addition to conventional desalination methods. This could be a promising solution for poor countries with limited infrastructure facing water scarcity challenges. In this study, an experimental setup utilizing a conventional vapor compression cycle (VCC) is designed, built, and tested to produce drinkable water by removing and collecting moisture from humid air. The setup includes an Aluminum-Copper finned tube condenser and a coil-shaped Copper evaporator placed perpendicular to the airflow direction in a horizontal configuration. A controlled fan is used to drive the airflow throughout the system, with the dehumidified cold air from the evaporator directly cooling the condenser for improved energy recovery. The dew point temperature (DPT), relative humidity (RH), and ambient temperature were monitored during experiments. Results show that this system yields an average of 33 litres/m2 per day where the DPT > 12°C and RH > 55%.
A Novel Device for the Standardized Intraoperative Preparation of Non-Valved Glaucoma Tube Shunts
Authors: Alzoubi Faleh , Laird Jack , Mallory Caleb , Stewart Mallory , Zachariah Natalie , Eichaker Lauren , Evans Joshua
Published: February 2024

Glaucoma refers to a category of eye conditions that involve damage to the optic nerve and is characterized by high intraocular pressure (IOP). This optic nerve damage causes pain and discomfort; in chronic cases, it can lead to long term vision loss and sometimes blindness. After failure of preliminary treatment such as drops and medication, late-stage glaucoma patients often undergo surgical intervention in which a drainage shunt is implanted to lower IOP. The shunt tube implantation surgery remains variable in both procedures and outcomes as there does not exist a one-size-fits-all-method or tool for implant and procedure customization.

There is currently a lack of predictability of outflow characteristics of tube shunt fenestrations due to the lack of a method to standardize the creation of fenestrations, leaving the number and size of fenestrations up to the surgeon. Additionally, the ligation of the base of the tube can be difficult and time consuming, which can lengthen surgical time.

Towards improving non-valved tube shunt procedures, this study describes a novel device to standardize the creation of fenestrations in tube shunts at the bedside. The device will standardize the size and placement of the fenestrations by acting as a guide to place a blade or needle. In this way the guide will allow for predetermined fenestrations to be placed at standard depths. Additionally, a preliminary mathematical model has been created to predict outflow characteristics of the novel device as a function of fenestration number. Validated mathematical models hold clinical value in predicting outflow characteristics and tailoring patient care.
Investigation of Nanomechanical Properties and Interphase of Variable-Size Hard Particles in a Soft Matrix in Atomic Force Microscopy and Finite Element Analysis
Authors: Norkus Tyler , Yekani Fard Masoud
Published: February 2024

Hard particles suspended in a soft matrix significantly change the properties of the surrounding matrix via interactions with matrix and through the interphase that surrounds the particles, and atomic force microscopy (AFM) is one of the techniques that has been used to characterize the nanoscale properties of such composites. AFM performed on particle-matrix composites results in complicated force-displacement data, and significant effort must be made to analyze that data. Finite element analysis (FEA) will be used in conjunction with experimental data to deconvolute and analyze the complex interactions between the AFM probe and particle-matrix composite. Previous work has been done to characterize both filled rubbers and biomaterials — which can be modeled with simpler particle-matrix composites — but the scenarios that were considered did not portray the full extent of the AFM probe’s interactions with the hard particles or matrix. A neo-Hookean constitutive material relation is assigned to the soft matrix, and the Derjaguin-Muller-Toropov (DMT) and Johnson-Kendall-Roberts (JKR) contact mechanic models are considered during analysis of the probe-particle interactions. Data from AFM performed on hard carbon nanotube (CNT) particles embedded in thermoset epoxy resin will be collected to supplement and verify FEA. Simulated force-displacement and stress field data are analyzed to extract nanoscale mechanical properties and identify the key impacts different geometries have on collected AFM data.
On the Development and Evaluation of an Affordable Telerobotic System for Object Grasping for Human-Machine Interaction
Authors: Abdul Rahaman Abdul Hafiz , Hazra Sudip , Shiakolas Panos S.
Published: February 2024

Due to mobility impairment, a person might rely on wheelchairs, canes, and crutches for assistance but could face challenges when performing tasks such as grasping and manipulating objects due to limitations in reach and capability. To overcome these challenges, a multi-degree-of-freedom robotic arm with an anthropomorphic robotic hand (ARH) could be used. In this research, we propose an architecture and then implement it towards the development of an assistive system to assist a person with object grasping. The architecture interlinks three functional modules to provide three operation modes to calibrate the system, train a user on how to execute a grasp, synthesize grasps, and execute a grasp. The developed system consists of a user input and feedback glove capable of capturing user inputs and providing grasp-related vibrotactile feedback, a CoppeliaSim-based virtual environment emulating the motions of the ARH, and an underactuated ARH capable of executing grasps while sensing grasp contact locations. The operation of the developed system is evaluated to determine the ability of a person to operate it and perform a grasp using two control methods; using a synthesized grasp or under real-time continuous control. The successful evaluation validates the architecture and the developed system to provide the ability to perform a grasp. The results of the evaluation provide confidence in expanding the system capabilities and use it to develop a database of grasp trajectories of objects with different geometries.
Analysis of Contact Positions of Inspection Tool for Motorcycle Safety Verification
Authors: Inui Masatomo , Umezu Nobuyuki
Published: February 2024

We propose a method for automatically detecting shapes that may be dangerous to pedestrians in the event of a collision using a motorcycle’s CAD model for its safety verification. A columnar inspection tool comprising a conical surface and cylindrical surface with a diameter of 300 mm, imitating an upright person, was prepared for this verification. The shape of the contact of the motorcycle with inspection tool is recognized as a shape that can cause severe injury to a pedestrian in a collision, which is modified at the designer’s discretion. The proposed technique detects the location of the inspection tool in contact with the motorcycle. It then detects the surface portions of the motorcycle that establish contact with the tool placed at that location. The former process involves slicing the CAD model of the motorcycle into several horizontal planes placed at small intervals, expanding the resulting cross-sectional figures by the radius of the inspection tool, overlapping the expanded figures, and calculating their Boolean union shape. To accelerate these processes, we developed an algorithm that leverages the parallel processing capabilities of a graphics processing unit. Computational experiments confirm the effectiveness of the proposed method.
Comparison of IZOD Impact Energies and Ductile to Brittle Transition Behavior of 3D Printed vs. Sheet Extruded Polymers
Authors: Coates Cameron , Adams Aaron , Johnson Wayne , Foster Ryan , Cook Christian
Published: February 2024

This work investigates the difference in impact response of sheet extruded vs 3D printed Polyethylene Terephthalate Glycol (PETG) and High Impact Polystyrene (HIPS). The effect of a machined notch vs a 3D printed notch, the effect of the raster angle, and the role of percentage infill are also examined. IZOD impact energies at temperatures ranging from −50°C to 50°C in 5°C intervals are experimentally obtained for 3D printed and extruded specimens. 3D printed specimens tested had 25% infill, 100% infill, 60° raster angle, 90° raster angle with machined and 3D printed notches.

For a 90°-raster angle, increasing infill percentage from 25% to 100% may increase the impact strength of 3D printed PETG and HIPS by 20% and 42% respectively. These gains do not seem to occur for a 60°-raster angle, neither were these gains consistent for machined notched specimens. 3D printing PETG or HIPS will generally result in materials whose DBT regions will have slopes up to 70% gentler than their sheet extruded counterparts. An increase in raster angle from 60° to 90° may reduce the DBT slope by up to 60% for either material. If an adjustment of the DBT slope is sought by altering the infill percentage for these 3D printed materials, careful attention must be paid to the raster angle used.
Phased Array Ultrasonic Nondestructive Testing for Mechanical Integrity Assessment of Steel Welding
Authors: Williams Caleb , Taheri Mohammad , Taheri Hossein
Published: February 2024

Variety of structures and components are using welding processes as the major method of joining. Various materials such as steels, aluminum alloys, nickel alloys, and cast iron are being welded regularly in industrial applications. Well-known methods of welding are available which being used depending on the type of the materials welded together and application requirement. Like any other sections of a manufactured component, welding parts need to be inspected for required level of quality and integrity. Welding inspection typically consists of a series of quality assessment actions carried out in a certain procedure. It ensures welded joints meet required levels of quality and are fit for a specified purpose. A range of nondestructive testing (NDT) techniques may be used for welding inspection which depends on several factors including geometry and configuration of the joints, material, thickness of the welded parts, and inspection environment. Among the variety of NDT methods, configurations of ultrasonic testing (UT) are identified as efficient and accepted techniques of inspection for welding. Many UT methods are based on traditional techniques. Despite the effectiveness of these techniques, the accuracy and repeatability of the UT can be significantly improved via advanced phased array technology. In this study, phased array UT (PAUT) is used to evaluate the quality of the welding in steel samples. In addition, mechanical properties of the samples were measured by tensile testing and monitored with acoustic emission technique. Results show that the phased array ultrasonic testing can provide localized quality information of the weld and correlate to the mechanical properties (e.g., strength) of the part in welding region.
Development of Paper-Based RNA Amplification Devices for Point-of-Care Detection of HIV
Authors: Adedokun George , Sidhu Gurjit , Wang Gary P. , Fan Z. Hugh
Published: February 2024

Point-of-care (POC) testing of human immunodeficiency virus (HIV) infection is challenging in resource-limited settings, where conventional nucleic acid tests are costly and complex. Paper-based devices offer a low-cost, simple, and rapid alternative, but most of them rely on antibody or antigen detection, which have limitations in sensitivity and specificity. In this work, we develop and evaluate a miniaturized platform for the detection of HIV infection in resource-limited settings. The platform uses low-cost and environment-friendly paper for sample preparation as a nucleic-acid-extraction substrate followed by isothermal amplification in a battery-powered coffee mug and colorimetric detection. Our platform can detect HIV in human serum and plasma samples with high sensitivity and specificity. We demonstrate the feasibility and performance of our platform using clinical samples and compare it with conventional nucleic acid tests.
Study of the Thermal Performance of a Medical Device Packaging System Using Phase Change Material
Authors: Biswal Amrut , Yildiz Salih , Roth Arti , Upadhyaya Sam
Published: February 2024

Medical devices and biologics require to be maintained within specific temperature bands for the product to be safe and effective for treatment. It is a particular challenge during the distribution of products from manufacturing to healthcare facilities when active temperature control is not available. Phase change materials have greatly been used in medical packaging systems to keep the device within the specified thermal conditions. Determining the suitable phase change material as well as the related packaging components are highly important to provide an acceptable environment for medical devices encapsulated by packaging systems. In this study, the thermal performance of a medical device packaging system was investigated. A computational thermal analysis model for the packaging system was conducted. In addition, an experimental set-up was developed, and the packaging system was tested in the environmental chamber. Thermal properties of the PCM obtained by Differential Scanning Calorimetry (DSC) test was validated by in-house experiments as well as a 3D computational model. Furthermore, the full packaging system was tested at −18°C for 24 hours after it was preconditioned at 35°C. The experimental results were compared to the 3D computational analysis. Lastly, the influence of the outer insulation box material and its wall thickness on the thermal performance of the packaging system under the standardized temperature profile (ISTA 7D) which may represent the distribution path of the packaging system was investigated using a computational modeling approach. Through this optimization study, an environmentally friendly, cost-effective, and robust packaging system for medical devices was obtained.
Combined Effect of Hydrogen-Enrichment and Stratification on the Stability and Structure of Premixed Swirl-Stabilized CH4/Air Flames
Authors: Abdelhalim Ahmed , Abdelhafez Ahmed , Nemitallah Medhat A.
Published: February 2024

Hydrogen-enriched flames are a viable solution to reduce greenhouse gas emissions and improve combustion efficiency in gas turbines and industrial applications. Hydrogen has advantages over conventional fuels, such as higher flame speed and a broader flammability range. These benefits lead to more efficient and stable combustion, resulting in improved efficiency, reduced emissions, and increased power output. However, a drawback of hydrogen-enriched flames is the elevated temperature, leading to higher NOx emissions. To tackle this issue, lean swirl-stabilized combustion and stratification techniques are used. The first one enhances combustion efficiency, stability, and reduces emissions, while stratification introduces a non-uniform distribution of fuel, improving the static stability of flames. The DACRS burner is an example of stratified combustors used in gas turbines. By combining hydrogen-enrichment, stratification, swirl-stabilization, and lean operation, combustion systems in gas turbines and industrial combustors can be significantly improved. The present study examined the stability and combustion properties of a hydrogen-enriched, lean, stratified CH4/air flame in a gas-turbine burner. The study varied the hydrogen fraction and equivalence ratio and found that the combination of stratification and hydrogen enrichment had conflicting effects on flame stability. The flame blowout limit remained unchanged, even with up to 20% hydrogen enrichment. NOx emissions were not affected by hydrogen addition up to 20%, but increasing the equivalence ratio promotes NOx formation, as anticipated.
Reduced Order Model of Parametric Resonance of Electrostatically Actuated Cantilever Resonators: Comparison Uniform Versus Non-Uniform Resonators
Authors: Caruntu Dumitru , Flores Rigoberto
Published: February 2024

A comparison of the frequency-amplitude and voltage-amplitude responses of parametric resonance between electrostatically actuated uniform and non-uniform cantilever resonator is conducted. The non-uniform cantilever resonator has constant width and linearly varying thickness. Both microstructures uniform and non-uniform are under soft AC electrostatic actuation. Two Reduced Order Models for predicting the responses of the MEMS cantilever are used in this paper, namely one using one mode of vibration, and another one using two modes of vibration. The Method of Multiple Scales is used to solve the Reduced Order Model with one mode of vibration. A second method is a direct numerical integration is used to solve the Reduced Order Model with two modes of vibration to predict time responses of the MEMS cantilever. A third method uses AUTO 07P, a continuation and bifurcation software, to predict the responses of the MEMS cantilever. A comparison between the three methods is conducted as well.
Analytical and Numerical Analysis of the De Haller Criterion for Low-Pressure Axial Fans
Authors: Fritsche Manuel , Epple Philipp , Delgado Antonio
Published: February 2024

During the design process of low-pressure axial fans, load criteria are often applied to minimize losses and obtain optimal machines. Particularly in the case of decelerated flows, such as in a blade channel of an axial fan, the flow tends to detach and form vortices due to the positive pressure gradient. Exactly 70 years ago in 1953, based on experiments on a linear blade cascade in a wind tunnel, De Haller suggested limiting the velocity reduction between blade outlet and blade inlet to a ratio of 0.75.

This De Haller criterion was analyzed in more detail in the present study. The De Haller criterion is examined on the basis of 16 different three-dimensional analytical impeller designs considering the radial equilibrium with different blade work distributions. Due to the three-dimensional approach in the radial and axial direction on several annular surfaces, it is possible to determine the existing flow field analytically. Due to the variation of the blade work distribution, the impeller is loaded differently, which leads to a change in the flow velocities and thus in the velocity reduction between blade inlet and outlet. The De Haller number can thus be examined using different blade work distributions.

These analytical designs have been simulated using numerical flow simulation methods (Computational Fluid Dynamics - CFD). The three-dimensional CFD model was modelled with ANSYS Workbench 2022R2 and the RANS equations were solved with ANSYS CFX, after performing a detailed grid independence study based on the Richardson extrapolation. From the simulated CFD model, the velocities on the corresponding ring surfaces were evaluated and the associated De Haller number was determined. Two criteria were applied in order to quantify the flow detachment in order to compare the CFD results with the De Haller criteria. The first one is the flow blockage percentage, which indicates how much of the flow is detached and the second one is the wall shear stress on the blade surface, which indicates how well the flow is attached to the blades. Finally, the analytical and the numerical results are compared and the respective De Haller numbers are analyzed. There is a systematic deviation between the analytical design and the numerical simulation. The De Haller numbers of the numerical simulation are always higher than those of the analytical design. This is due to the non-ideal flow deflection in the blade channel. The analytical results and the numerical CFD simulations are explained and presented in detail.
Numerical Investigation of the Mechanical Behavior of Shape Memory Alloy Triply Periodic Minimal Surface Primitive Lattices
Authors: Zaki Wael , Viet Nguyen
Published: February 2024

This work investigates the mechanical behavior of a Schwarz primitive (SP) triply periodic minimal surface (TPMS) lattice made from superelastic nitinol shape memory alloy. The investigation uses numerical homogenization to determine the effective response of a unit nitinol SP cell subjected to a reduced set of periodic boundary conditions that account for the cubic symmetry of the considered SP topology. The simulation of the mechanical behavior of the unit cell is carried out by means of finite element analysis using an implementation of the Zaki-Moumni (ZM) model for shape memory alloys. The analysis considers the influence of temperature and relative density on the mechanical and phase transformation behavior of the SMA SP lattice. The effective stress-strain response of the lattice, in the superelastic temperature range, shows smooth phase transitions characterized by less abrupt changes in the slope of the stress-strain curve compared to dense nitinol. Moreover, later stages of the material phase transformation from austenite to martensite are shown to approach completion in an asymptotic fashion in terms of the applied load, with full transformation corresponding to asymptotically high applied strain. The onset of phase transformation is found to describe an ellipsoidal hypersurface in stress space, which is shown to adequately fit an extended Hill’s loading surface that accounts for the influence of hydrostatic pressure. Moreover, the loading surface is found to evolve with the applied load in a way similar to isotropic hardening, whereby the center of the surface remains fixed whereas the size of the elastic domain increases monotonically with increased cumulated phase transformation, defined as the integral from zero of the magnitude of the differential increment in martensite volume fraction as the load applied to the nitinol lattice cell is varied. The reported findings contribute to understanding the behavior of architected nitinol lattice metamaterials and provide an important element in developing constitutive models that can describe their complex mechanical and functional response.
On the Prediction of Mechanical and Aesthetical Behavior of AM Specimens Through Machine Learning: A Preliminary Study
Authors: Greco Alessandro , Russo Mario Brandon , Gerbino Salvatore
Published: February 2024

3D printing, including the widely used technique of Fused Filament Fabrication (FFF), offers several benefits, such as freedom in design, faster production times, customization, and lightweight. In fact, it has the potential to serve a variety of sectors, from the everyday products market to the industry. However, the properties of FFF parts, in terms of mechanical strength and geometrical accuracy, are strongly influenced by printing process parameters, necessitating thorough investigations.

This preliminary study proposes a comparison between data-driven Machine Learning (ML) models, i.e. Quadratic Regression (QR), Regression Tree (RT), and Neural Network (NN), to predict the impact of printing process parameters on both mechanical (tensile properties) and aesthetical (bending angle, thickness, and flatness tolerance) behavior of additively manufactured tough-Polylactic Acid (PLA) specimens. The investigated models were trained by using experimental data obtained from Design of Experiment (DoE) where the building orientation on plate, the infill percentage and the pattern were varied. An additional dataset was used to test the accuracy of the prediction.

The results suggest that ML models perform well in predicting the tensile properties, particularly the Ultimate Tensile Stress (UTS). At the same time, further investigation is necessary to improve the prediction for aesthetical features.
Multiscale Mechanical Characterization of Cornea With AFM, SEM, and Uniaxial Tensile Test
Authors: Zhai Yingnan , Colmenarez Jose A. , Mendoza Valentina O. , Dong Pengfei , Nunes Kenia , Suh Donny , Gu Linxia
Published: February 2024

Cornea stiffness is associated with the progression of keratitis, aging, and glaucoma diseases. Knowing the microstructure and mechanical properties of the cornea is important for cornea tissue engineering. In this study, the microstructure and mechanical properties of the cornea from African green monkey eye were determined through multiscale methods with atomic force microscopy (AFM), scanning electron microscopy (SEM), and uniaxial tensile test. The cornea samples were dissected from the eyeball of African green monkeys. Cornea microstructures were inspected by SEM and optical microscopy for corneal stroma collagen lamellae. The aligned collagen lamellae have a width of approximately 3–6 μm. The stiffness map of cornea stroma with scanning regions of 10 × 10 μm2 and 5 × 5 μm2 was detected by AFM indentation test. The average Young’s modulus determined by AFM was 238.2 ± 32.7 kPa, which is on the same scale as the toe modulus (402.1 ± 176.7 kPa) of the stress-strain curve (linear region of 0%–5% strain) obtained from uniaxial tensile test. The heterogeneity of corneal stroma stiffness was presented in the stiffness map with line-shaped and band-shaped regions showing higher Young’s Modulus (around 250 kPa). The width of the band-shaped region is around 3.7 μm referring to collagen lamellae, while the adjacent arbitrarily shaped region with lower Young’s modulus (< 70 kPa) on the stiffness map refers to keratocytes. Corresponding histograms show two-phase characteristics with one peak at a lower Young’s modulus range of 0.027–0.574 kPa, and another peak at a higher Young’s modulus in the range of 250.0–263.3 kPa. Monkey cornea shows heterogeneous and nonlinear mechanical properties over the scale of the tests.
A Manufacturing Compensation Method As Applied to CFRP Components in Aero Engines
Authors: Lööf Johan , Frampton Andrew , Wärmefjord Kristina , Söderberg Rikard
Published: February 2024

In this paper the focus is on applying compensation to the manufacturing process based on the results of shape distortion simulation for composite CFRP (carbon fibre reinforced polymers) parts. The objective of the simulation is to predict the deformation due to the manufacturing process to enable the lay-up, compression and mold tool to be modified to compensate for these distortions to achieve a net shape component at the end of the process. A case study is presented to demonstrate how the results from the shape distortion simulation can be used to compensate for the global deformations. This case study describes the complete process on how to go from a nominal CAD model (design intent) towards to a virtually designed compensated lay-up and mold tool.
Investigation of High-Pressure Laminar Flame Speed Measurement
Authors: Shaffer James , Alvarez Luis F. , Askari Omid
Published: February 2024

Laminar burning speed (LBS) measurements are a significant fundamental experiment in understanding the combustion characteristics of fuels of interest. Such information is necessary for many applications such as engine design or modeling more complicated combustion phenomena. For example, to improve the thermal efficiency of combustion devices such as turbines or jets, it is generally necessary to operate at higher pressure or with lean fuel mixtures. Therefore, accurate measurement of fuels under these relevant conditions is of interest to accurately simulate the behavior of such devices. At these desired experimental conditions, the flame is often affected by instabilities (surface wrinkling and buoyancy), which can make LBS measurement challenging or impossible. Such instabilities are enhanced (occur earlier in the flame propagation) at high pressure where the flame thickness is decreased and propagates at a slower speed. This work demonstrates that the inclusion of flame propagation data at small geometries (r < 8 mm) can improve the measurement of LBS through the addition of early flame propagation. In the conventional measurements, flames of this size are excluded from analysis because experimental data is affected by the ignition plasma source. The effect of ignition on the propagation rate is in general not known, and an accurate time-resolved method for characterizing ignition for use in LBS measurements is not available. It has been found that an improved LBS measurement method can be developed if the ignition can be accurately characterized.
Investigation Into Mechanical Properties of Expanded Polystyrene Fresh Fish Boxes Using Finite Element Analysis and Experimental Methods
Authors: Lu Ziwei , Jónsdóttir Fjóla , Arason Sigurjón , Margeirsson Björn
Published: February 2024

Expanded polystyrene (EPS) is used as packaging material in transportation. To reduce environmental impact, it is crucial to minimize the consumption of packaging materials and maximize strength meanwhile. To reduce consumption, reducing the density of EPS is one method, and structural optimal design is the other. Therefore EPS boxes with densities of 22 kg/m3 are introduced to compare with the mass-produced 23-kg/m3 model. Regarding structural optimal design, as compressive and flexural properties underlie the optimization of structures and have been well-studied in construction, they have not been thoroughly explored in packaging. Material parameters obtained from a compression test are used in a finite element simulation of a stacking test, and good agreement is observed between the simulation and experimental results. The findings indicate that density impacts the initial modulus and compression/flexure strength, as well as the stacking strength of a box to some extent. The study investigates box failure and uses theoretical calculation, simulation, and experimentation to determine the critical force, with all findings showing agreement. The study also examines how sample preparation methods affect mechanical properties, specifically comparing cutting EPS with a hot wire and a table saw, and finds that differences are typically around 2%.
Measurement of Optimum Laser Energy Required to 3d Print Continuous Fiber Reinforced Composites Using Photo-Curable Thermoset Resin
Authors: Islam Md Zahirul , Rahman Md Atikur , Gibbon Luke , Hall Eric , Ulven Chad A. , La Scala John J.
Published: February 2024

Continuous carbon fiber (CCF) reinforcement has garnered significant attention in 3D printing due to its ability to impart exceptional mechanical performance characteristics to polymer composites. Light-assisted 3D printing of thermoset resin with CCF reinforcement enables the scalable production of complex structures using additive manufacturing. However, the opaqueness of carbon fiber poses challenges to the curing process of thermoset resins during printing with CCF reinforcement. Therefore, knowledge on the minimum light energy required to continue printing while retaining the desired print shape is crucial for designing energy-efficient and successful manufacturing systems. The primary objective of this study was to measure and compare the minimum energy required to continue light-assisted 3D printing of thermoset resin with CCF reinforcement. The study specifically investigated the minimum light energy needed for printing with both an acrylate-based thermoset resin and an epoxy-acrylate resin. Optimized laser irradiation with the appropriate light energy is imperative for achieving scalable production of CCF reinforced composites with minimum energy consumption.
A Dynamic Model for Underwater Propulsion of an Amphibious Rover Developed From Kane’s Method
Authors: Donohue Brigid , Beknalkar Sumedh , Bryant Matthew , Mazzoleni Andre
Published: February 2024

The Multi-terrain Amphibious ARCtic explOrer (MAARCO) rover is an amphibious arctic rover designed to traverse arctic terrains and propel through water. The MAARCO rover consists of an ellipsoid chassis with links connecting to the propulsion system. The propulsion system consists of two helical drives made up of hollow cylinder ballasts wrapped in auger or screw shaped blades in opposing helical directions parallel to each other. In this paper, a 6 degree of freedom dynamic model of the MAARCO rover is created using Kane’s method dynamic modeling to demonstrate the dynamic model capabilities for an underwater vehicle’s performance. The hydrodynamic forces considered on the underwater rover include drag, buoyancy, flow acceleration, and added mass. In addition to the hydrodynamic forces the rover will experience gravity forces, control forces, net thrust from the helical drive blades, and net buoyancy from the helical drive ballast system. The equations of motion are developed from Kane’s method to reduce computational cost and simulated in MATLAB for different cases to gain further understanding and provide a visual representation of the system underwater and the dynamic models capabilities. The results of the simulations show the MAARCO rover behavior in the hydrodynamic environment. The results reveal that the Kane’s method dynamic modeling successfully develops equations of motion of a complicated system that can be implemented into a control system.
Enhancing Sample Efficiency for Temperature Control in DED With Reinforcement Learning and MOOSE Framework
Authors: Sousa João , Darabi Roya , Sousa Armando , Reis Luís P. , Brueckner Frank , Reis Ana , de Sá José César
Published: February 2024

Directed Energy Deposition (DED) is crucial in additive manufacturing for various industries like aerospace, automotive, and biomedical. Precise temperature control is essential due to high-power lasers and dynamic environmental changes. Employing Reinforcement Learning (RL) can help with temperature control, but challenges arise from standardization and sample efficiency. In this study, a model-based Reinforcement Learning (MBRL) approach is used to train a DED model, improving control and efficiency. Computational models evaluate melt pool geometry and temporal characteristics during the process. The study employs the Allen-Cahn phase field (AC-PF) model using the Finite Element Method (FEM) with the Multi-physics Object-Oriented Simulation Environment (MOOSE). MBRL, specifically Dyna-Q+, outperforms traditional Q-learning, requiring fewer samples. Insights from this research aid in advancing RL techniques for laser metal additive manufacturing.
Analysis of Sustainable Building-Insulation Material Using Biochar and Natural Fiber
Authors: Mondal Sourov Kumar , Gomez Hector , Nasef Ziad , Diaz Gerardo
Published: February 2024

Natural insulation materials like hemp, cotton stalks, cardboard, and paper fiber are of great interest in the construction industry due to their natural composition and sustainability. Biochar can be produced from the pyrolysis of biomass which constitutes a carbon negative process. In this study, an experimental approach is utilized to analyze the effect of using biochar mixed with natural fibers as insulation material with the purpose of using them in the construction industry. Comparative studies were conducted for insulation using natural fibers with and without biochar. The effect of biochar in the thermal performance of the insulation materials is investigated first, by determining the thermal conductivity and R-value from tests. Then compression and bending tests were performed to determine the effect of biochar on the mechanical performance of building-insulation materials. The main contribution of this paper is to investigate the potential utilization of biochar mixed with natural fiber as building-insulation materials to improve fire-retardancy as well as achieving a stable form of carbon sequestration.
Investigation of Mechanically Fatigued Low-Frequency Energy Harvesting Effect on Isotropic Materials
Authors: Meade Daniel , Ahmed Hossain , Ahmed Riaz , Riggs Patrick
Published: February 2024

One of the most popular methods of harvesting electrical energy from mechanical stress is the utilization of piezoelectric materials. A significant amount of research has been done regarding piezoelectric material and has answered questions about what happens to the piezoelectric material during energy harvesting. However, the question that has yet to be answered is what happens to the properties of the material from which energy is being harvested. To answer this question, this study will focus on a simple energy harvesting system is designed that consists of a piezoelectric transducer, voltage regulator, rectifier, and energy storage element to collect energy. The base material from which energy is being harvested is an ASTM standard dog bone test piece of aluminum 6061, structural steel, and copper. To harvest energy from the test specimen, a low-frequency mechanical fatigue load is applied using a fatigue testing machine. Based on the SN curve estimated for the aluminum 6061, structural steel, and copper, the number of fatigue cycles for the test specimen is determined. The maximum fatigue tensile amplitude is set as half of the yield point of the aluminum. The test specimens are designed to go through three types of fatigue cycles which are 50%, 80%, and 100% of their strength. From each set of specimens, energy is harvested from a simulated time as defined in the study. The results of these experiments show a clear correlation between the harvested energy with the material strength of the mechanically fatigued isotropic structures. As the material strength decreases, the amount of energy that is extracted also decreases. Moreover, as the frequency increases, the amount of harvested energy increases exponentially. From each set of specimens, energy is harvested from half the time the experiment runs. At the end of each set of experiments, the ultimate tensile strengths are determined in order to observe if energy harvesting has negative, neutral, or positive effects by comparing the strengths of energy-harvested specimens to the non-harvested tensile strength. To understand the uniform effect of harvesting, the final strength is normalized with the amount of energy being harvested from the material. The results of these experiments show a clear correlation between the harvested energy with the final strength of the mechanically fatigued aluminum structure. As the material strength decreases, the amount of energy that is extracted also decreases. As the frequency increases, the amount of energy increases exponentially.
Development of Sub-Surface Laser Additive Manufacturing Process for Liquid Resins
Authors: Riggs Patrick , Silva Julio , Quirino Rafael , Ahmed Hossain
Published: February 2024

The goal of the present study is to develop original research revolving around plastics-based Laser Additive Manufacturing (LAM) that seeks to improve the current quality, print time, strength, and post-processing needed for LAM. This is accomplished through repurposing a sub-surface laser engraving (SSLE) machine that solidifies bio-resin through thermal polymerization. SSLE machines are traditionally used to create greyscale art pieces that are suspended in a solid crystal block. This is accomplished through focusing the laser below the top surface of the crystal and creating micro-fractures in the material that are around 20–30 μm in size. By keeping the same general process of SSLE, but changing what medium the laser interacts with, this experimental research seeks to replace the micro-fractures with micro-solids through laser induced thermal polymerization in resin. A resin with 50% (weight) of Tung oil is considered for its eco-friendliness. An SSLE machine equipped with a diode pumped Nd: YAG laser is customized to focus laser energy at the subsurface of the resin medium. Several advantages are hypothesized for this new additive manufacturing technique including the elimination of strictly defined layer lines, no longer needing a build plate for the part to build from, the absence of support material as any overhangs will be suspended in the uncured resin, enhancement of surface quality, and the improved strength found from a proposed Body Centered Cubic (BCC) lattice structure of the points. In combining these unprecedented advantages, it is expected that the Sub-Surface Laser Additive Manufacturing (SSLAM) would be an industry-leading advancement with a wide range of applications for commercial product development.
Development of Real-Time Defect Detection Techniques Using Infrared Thermography in the Fused Filament Fabrication Process
Authors: Sadaf Asef Ishraq , Ahmed Hossain , Khan Md Arif Iqbal , Sezer Hayri
Published: February 2024

One of the most popular forms of Additive Manufacturing (AM) is Fused Filament Fabrication (FFF), which allows flexibility to work with multiple materials with comparatively low manufacturing costs. However, uncontrollable process factors lead to the underutilization of the full potential of FFF on an industrial scale due to occasional failure in 3D printed parts. These failures can scale from insignificant to critical defects, which can significantly compromise the overall quality of the product, including desired structural integrity, mechanical property, and reliability of the FDM-produced parts. Post-inspection of the printed part is inconvenient as they result in a loss of labor hours, print time, and print materials. To circumvent these issues, an in-situ real-time defect detection approach is proposed in this study utilizing Infrared (IR) thermography. While optical sensors can provide real-time images of in-printing parts, they are unable to measure the thermal deviations essential to evaluate FFF process. Since IR sensors can provide thermal information of in-printing FFF parts with acceptable resolution in the spatiotemporal domain, these sensors can be utilized as an alternative source of information applicable for monitoring the print states and print defects of various types. In this study, an IR sensor-based data acquisition system is designed and integrated into an existing FFF printer to collect in-printing layer-wise real-time thermal data. As the FDM printer starts printing each layer of a part, the thermal data stream produced by the IR sensors from the in-printing part is collected along with the nozzle and the print bed temperature. By establishing a data-driven correlation of the spatiotemporal information between the non-defective and defective parts, a field-deployable approach to detect defects in real time is demonstrated herein.
Non-Linear Measurements of Roughness Effects in Pulsing Restricted Flows
Authors: Byers Clayton P. , Ofori Sandra , Chapata Lincoln , Ning Taikang
Published: February 2024

The influence of surface roughness on the acoustic spectrum in a pulsing restricted flow is investigated over a range of roughness sizes and flow conditions. Four different roughness scenarios are introduced, ranging from smooth to a relative roughness of 0.0486 based on hydraulic diameter. These span three different restriction severities ranging from moderate (56% restricted) to severe (82% restricted) based on the American Society of Echocardiography rating of aortic stenosis. The influence of restriction and roughness on the distribution of energy in the acoustic spectrum is evaluated, showing that enhanced roughness correlates with higher frequencies (150–300 Hz) becoming prominent in the spectrum. This trend follows with increasing restriction. As the Reynolds number changes, the spectral shape is not significantly affected, but the relative amount of energy in frequencies greater than 150 Hz does increase. A measure of frequency coupling is investigated by calculating the bicoherence for these cases, providing another quantitative assessment of the data. As more roughness is introduced, frequency coupling diminishes across all restrictions and Reynolds numbers. This new metric may provide a way of assessing the roughness of an internal flow through non-invasive means.
Assessment of the Thermal Comfort and CO2 Distribution Within a Movie Theatre
Authors: Costa Ana Carolina , Rodrigues Nelson , Carneiro Ana Marta , Teixeira Inês , Machado Lúcio Manuel , Ferreira Ana , Teixeira José , Teixeira Senhorinha
Published: February 2024

Human occupation is both the major source of pollutants and the main drive for providing a comfortable environment in buildings. Indoors, public buildings require special attention as they are used by a large number of people at the same time. The present work develops the application of a CFD (Computational Fluid Dynamics) model to simulate the thermal field and species distribution inside a movie theatre and to analyze the Indoor Air Quality (IAQ) to evaluate the thermal comfort of its occupants. For this movie theatre, the dimensions, the layout and the system ventilation details were obtained. The cinema was simulated at a ¾ capacity, while occupants were defined as heat, water vapor, and CO2 sources. People were distributed within the cinema by using the occupancy probability based on past records of ticket sales over a two-month period. Measurements also included the variables related to the thermal environment and the Predicted Mean Vote index. In addition to the thermal environment, the simulation included the release of CO2 through breathing. Based on the results, it was possible to conclude that the presence of people affects shows an increase of temperature, water vapor and CO2, mostly confined to the vicinity of the seats. Nevertheless, the actual ventilation system provided enough airflow for CO2 dispersion. The Predicted Mean Vote simulated overpredicted the experimental data, although by a small amount. Nonetheless, both values were below zero, indicating a cold sensation trend. Finally, it was verified that the flow rate at the inlet is within the parameters required by Portuguese legislation for the minimum flow rate of new air.
Teaching a Developed First-Year Flipped Classroom
Authors: Thamban P. L. Stephan , Fadda Dani , Rios Oziel
Published: February 2024

Teaching a mechanical engineering class for the first time requires significant preparation and content development. While a flipped classroom can be effective for student learning, course development can be quite difficult for the faculty. However, when a course is developed in a modular flipped classroom model, faculty, teaching the course for the first time, can benefit from the developed content. They can use and make improvements to modules based on their areas of expertise without affecting the entire course. The paper provides the perspective of a faculty member teaching a developed first year introduction to mechanical engineering course with the modular flipped classroom model.