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

Accumulative knowledge on Thermal Energy Storage (TES) is imperative in society today because technology is ever expanding, opening doors for improved innovation that is more sustainable to our environment. TES has a multitude of uses; from simply boiling a kettle of water on a stove to more complex applications such as solar power generation. This research focuses on the application of a thermal energy storage unit introduced to a selected Phase Change Material (PCM) to undergo controlled experimentation. It helpful to gain understanding of how the TES unit will perform in a typical laboratory environment. A PCM is any substance capable of absorbing or releasing sufficient energy to undergo a phase transition. For specified purposes of this work was, the relevant states of matter liquid and solid; hence the use of a paraffin wax was the ideal for the experimental work model where the phase transition from solid to liquid occurs in a relatively low temperature. The objective of this work was determining the amount of energy that can be stored, and the power that can be generated by using paraffin wax. The setup of the experimental work for this project was consisting of a wax chamber, corrugated steel plates, and gaskets compressed within two plexiglass frames with an inlet and outlet. Tap water was used the medium of transferring thermal energy, and a JULABO heating unit was used to generate enough thermal energy for the steel plates. PCM was used to absorb the energy and transfer it to the cold water during the PCM transformation. A normal faucet was to provide cool enough water to lower the temperature within the system initiating the liquid to solid phase transition. Hoses was used to connect the main TES unit, JULABO unit, and faucet, as well as allowing flow throughout the system. Experiential work and calculation model results shows that the energy recovery was effected by flow rates, melting temperatures, and PCM. Other factors were considered in this work including mass, volume, density, specific heat, latency, turbulence flow, Reynolds number, limitations, and factor of safety. The results of this work can be used to get useful energy especially in isolated location such as desert, ships in occasion, and military locations.
Development of an Organisational Framework for the Optimal and Efficient Selection of Actuators
Authors: Hanna Pavlos , Carmichael Marc , Clemon Lee
Published: January 2022

Actuators are a vital component, and more often than not one of the limiting factors in robotics and robotics related applications. For the use of actuators in robotics related to humanoids, exoskeletons, prosthetics and orthoses, there are more factors that influence the selected actuator than the basic mechanical outputs, size, backlash, material and power consumption. The main interest within these applications is that because the device is being carried by the human user, thus weight, power consumption and form factor are important selection parameters. The correct selection of an actuator for these applications is a difficult and lengthy process to perform. This paper creates an organizational framework and database for searching the wide range of actuators. This dataset is organized into a design tool that plots the properties of each actuator on varying graphs creating trade-off Ashby charts to rapidly narrow the selection space for designers. A case study is performed to demonstrate the use of this design tool in human-centric actuation applications. The database is utilized in the selection of the ideal actuator based on lines of best fit and a multivariate regression analysis for the optimization of parameters about the required specifications. In addition, a meta-analysis identifies clusters of current actuators, gaps for new developments, and trends. This work provides research direction into developing specific actuators to fit into these trend gaps which offers substantial benefits to humanoids, exoskeletons, prosthetics and orthosis.
Theoretical Analysis of Geometrically Modified Dew Point Evaporative Cooler
Authors: Patunkar Prashant , Dingare Sunil V.
Published: January 2022

Human thermal comfort being one of major aspect of increasing demand of energy consumption for heating, ventilation and air conditioning (HVAC) sector. The vapor compression refrigeration systems are predominantly used in the conditioning of the air. Such systems are energy intensive on account of the mechanically driven compressor, hence, not to be considered as a long-term option. It is the need of an hour to propose alternative and sustainable method for the cooling requirements.

The evaporative cooling is considered one of alternative cooling method. Such technique helps to cool the incoming air only up to the wet bulb temperature of the air. The continuous development in the past have proposed the indirect cooling methods to achieve the purpose. This method helps to achieve the temperature closer to the dew point temperature of the incoming air. Dew point evaporative cooler is an indirect evaporative cooling (IEC) technique to lower temperature of incoming air below its wet bulb temperature and near to dew point temperature. Performance parameters of dew point evaporative cooler are significantly influenced by configuration and structural arrangement of heat exchanger. The different arrangements of heat exchangers commonly used are counterflow, cross flow and counter-cross flow. This work presents performance analysis of geometrically modified dew point evaporative cooler. The commonly used geometries for the construction of heat and mass exchangers are flat plates, corrugated plates, plates with the perforations etc. In this work, the plate geometry shape is modified to corrugated trapezoidal plates for the theoretical analysis. The modified geometry helps to provide more heat exchange area for the same heat exchanger volume. The cooling efficiencies and temperatures at the outlet of the cooler were investigated for different intake air temperatures and moisture content. The incoming air temperatures are varied from 25°C to 45°C and moisture content from 7 g/kg to 26g/kg for the fixed inlet velocity of 2.5 m/s. The wet bulb and dew point efficiencies ranged from 80% to 131% and 58% to 89% respectively. The trapezoidal corrugated plates predict 17.5 % and 8.5% higher wet bulb efficiency as compared to flat plates and corrugated plate, while the dew point efficiency remains almost same.
Microstructural Analysis and Tensile Property Studies on Spray Cooled Friction Stir Welded Aluminium Alloy 2014
Authors: Mohamed Rafi Afrith Noor , Augustine Michael Duke Mystica , Santhanam Senthil Kumar Velukkudi
Published: January 2022

Conventional Friction Stir Welding has increased heat generation which results in improper dissolution of precipitates in Heat Affected Zone (HAZ) which develop the weakest section of the weld. In order to dissipate the heat beyond Thermo-Mechanical Affected Zone (TMAZ), spray nozzle with water and compressed air is used in this study. Friction Stir Welding assisted with cooling has been shown to improve the microstructure properties of the weld than normal friction stir welding process (FSW). This is because the grain structures in the nugget zone become finer when water is used as a cooling medium to dissipate the excess heat. Refined grain structure is known to improve the tensile strength and ductile properties of the weld. The welding was carried out using the spray setup at 1000 rpm and 44 mm/min. The flow rate of the nozzle setup was set to 72 ml/min. The tensile behavior of the welded specimen was then tested. The ultimate tensile strength of water cooled was obtained and compared with air cooled weld. Fracture analysis was performed using Scanning Electron Microscope (SEM) and the results are then compared. Microhardness values of various zones were then measured and compared. It was found that the weld obtained with water cooled friction stir welding possesses balanced hardness and tensile properties suitable for real life applications.
Compression Analysis Tests for Prototypes Made of Different Polymers
Authors: Deemyad Taher , Akula Vincent , Sebastian Anish
Published: January 2022

In this paper, we tested and compared the failure loading conditions for allowed pressure over prototypes of smart toilet seats with custom shapes and materials (Polypropylene homopolymer (PPH) & Polymethyl methacrylate (PMMA)). These tests were conducted to identify the allowable maximum loading condition on these prototypes. The main challenge in designing these tests, was the application of load, specific to the custom shape of the prototype seats. A custom loading platform was designed to facilitate the application of a distributed force, to find the maximum allowable weight to identify any weak/critical sections, and failing point/s for each of the designs. However, because of the deflection of the seats, which causes a nonlinear condition for compression analysis, combined with their complex shapes, simulation of the models in SolidWorks was not very accurate. To circumvent this shortcoming an actual test bed was built and used a high accuracy electromechanical tensile & compression testing machine to subject and compare the maximum allowable loading of the seats. The results showed the seats passed the compression tests but have some differences in the locations for failures and maximum allowable pressure.
Characterization of Electric Fan Noise Generation Due to Blade Geometry
Authors: Cole Liliosa-Eyang , Barez Fred
Published: January 2022

The flow surrounding the propeller of an electric fan contributes significantly to the noise emitted by low-pressure electronic fans designed to cool electronic equipment such as desktop computers. This study characterizes fan noise based on modification of geometrical features such as its hub diameter, blade length, blade thickness, blade angle of attack and number of blades.

Computational Fluid Dynamics and Computational Aeroacoustics simulations were employed to analyze sound pressure level on the fan rotor. A commercially available computer cooling fan was selected as a reference fan. Two constant rotational speeds were tested, 2,400 rpm and 4,500 rpm, yielding OASPL of 31.94 dB and 48.99 dB, respectively. The sound pressure levels visualized from the reference fan were within the range of noise emission advertised by two manufacturers for the same size of fan, with number of blades and rated voltage. Velocity magnitude profiles and pressure profile distributions were also generated to visualize the flow patterns and validate aerodynamic theories citing turbulent flow in the vicinity of the rotor, characterized by a vortex field, wakes and eddies in the Trailing Edge.

A reduction in hub diameter and an increase in the blade’s thickness resulted in considerable noise reduction. Consequently, an improved fan geometry was created by superimposing these design modifications yielding a 5.02 dB and 3.53 dB noise reduction for the two respective rotational speeds.
A Comparative Study of Adaptive Mode Decomposition Methods for Modal Response Extraction
Authors: Liao Yabin , Sensmeier Mark
Published: January 2022

Adaptive mode decomposition (AMD) methods have received significant interest in recent years as an effective means for analyzing signals of multi-components and high complexity. This paper investigates the feasibility of integrating AMD methods and modal response extraction, and performs a comparative study of few representative AMD methods including the empirical mode decomposition (EMD), local mean decomposition (LMD), empirical wavelet transform (EWT), variational mode decomposition (VMD), nonlinear mode decomposition (NMD), and adaptive local iterative filtering (ALIF) methods. The fusion of AMD and modal analysis adds adaptivity and flexibility into data processing and helps automate the modal analysis process. The comparative study will provide insights on the advantages and disadvantages of the AMD methods as to the application of modal analysis. In this comparative study, the six representative AMD methods are first applied to the free response of a simulated three-degree-of-freedom (3-DOF) system, to extract the modal responses associated with the three modes. After that, the methods are applied to a measured free-response signal of a polymethyl methacrylate (PMMA) beam to assess their capability of analyzing real signals. Finally, the findings are summarized and conclusions are drawn.
Analysis of Surface Roughness in End-Milling of Aluminium Using an Adaptive Network-Based Fuzzy Inference System
Authors: Balonji Serge , Okokpujie I. P. , Tartibu L. K.
Published: January 2022

End-milling is considered one of the well-known cutting processes that machines surface using cutter tools that operate at relatively high speed. In order to manufacture mechanical parts, existing studies suggest that minimum roughness could be obtained if the radial and axial depth of the cut, the feed rate, and the spindle speed is adequately adjusted. This study considers the results of an experimental investigation conducted on 30 samples of aluminum alloy AL-6061 using a CNC machine and analyzes the relationship between independent input parameters, taken within well-defined ranges, that characterize the machine setting and output performance of surface roughness. Because the surface finish is a major concern, the present study considers an Adaptive Network-based Fuzzy Inference System (ANFIS) for the modeling: The paper presents results of surface roughness prediction using ANFIS. Emphasis is put upon shapes of membership functions, types of FIS generation, and FIS training optimum methods as these configurations affect the most performance of the ANFIS model. Results expressed in terms of an accuracy tool named root mean square error (RMSE) are compared. ANFIS has a strong learning capacity, prediction accuracy and can capture nonlinearity problems. In addition, The ANFIS surface roughness prediction model is expected to improve the cutting processes and the manufacturing process in the industry through sustainable prediction analysis.
Effect of Geometry on Small Scale Venturi Nozzle Performance
Authors: O’Hern Hannah , Zhang Xiang , Abbasi Bahman
Published: January 2022

A parametric study was conducted on small scale, subsonic Venturi nozzles. The purpose of this study was to determine the effect of different operating conditions and different geometric parameters on the performance of the nozzle. In this study, the performance of the nozzle was defined as the ratio of suction mass flow to motive mass flow, or the suction ratio. The parametric study included 15 different nozzle geometries, under various operating conditions, for a total of 55 case studies. The parametric study was conducted using CFD in Ansys Fluent. Additionally, experimental validation was conducted for several 3D printed nozzles. Dimensional analysis of the parameters was completed to determine the form of a dimensionless correlation for the suction ratio as a function of the other parameters. The case studies were run through a constrained multi-variable global optimization code to determine the dependency on each dimensionless group. This correlation can be used as a design guide for Venturi nozzles. If operating conditions dictate an optimum suction ratio, the ideal nozzle geometry can be determined. Alternatively, based on the geometry of a given nozzle, the resulting suction ratio can be determined.
Computational Modeling and Analysis of Turbulent Flows in the Humidification Unit of the Continuous Positive Airways Pressure Device
Authors: Vuong Tung Xuan , Al-Jumaily Ahmed
Published: January 2022

In this paper, an investigation into the dynamics flow behaviour of a humidifier unit is carried out using the numerical simulation method. The Computational Aeroacoustics (CAA) with a hybrid approach is conducted in the ANSYS software environment.

The CFD simulations were used to investigate the internal flow behaviours of the humification fluid model. The predicted results have shown the internal flow characteristics combined with scatters, circulations, and separation behaviours. These behaviours are due to the installation of a baffle unit inside the humification unit. Turbulent and pressure fluctuations were used to predict the noise level generated within the system. The predicted results are compared with the experimental results for validation. The comparison shows the predicted results agreed with the experimental result with some differences in frequency analysis.

In summary, the numerical model was developed for the CPAP humidifier unit to study the internal flow behaviours and the potential noise source location. The predicted results have explained and identified some locations of interest. These findings were used as guidelines to optimise and further develop to improve the future product. It also concludes that the CAA approach can be considered as a potential cost-effective tool in the early product development process for a better product design.
Mechanical and Thermal Characterization of Silica Particle-Reinforced Polymer Composites
Authors: Langat Hassan K. , Keraita J. K. , Mwema F. M. , Akinlabi E. T.
Published: January 2022

Polymer based composites are currently used in several fields including automobile, aerospace, biomedical, and domestic applications due to their high strength-to-weight ratio and other attractive properties. In the current study, silica particles are evaluated as reinforcement for three polymers namely, high impact polystyrene (HIPS), general purpose polystyrene (GPPS) and recycled low density polyethylene (rLDPE. The composites were prepared by varying the weight of silica particles in relation to the polymer matrix and then tensile, impact and thermal properties were evaluated using universal tensile testing machine, Charpy impact and differential scanning calorimeter (DSC) respectively.

The mechanical results showed that for HIPS-Silica composite, the tensile strength increased with increased silica content from 13.6 MPa for pure HIPS to 13.9 MPa at 5% silica and 14.8 GPa at 31% Silica. GPPS-Silica showed slight increase in tensile strength from 16.2 MPa for pure to 33.8 MPa at 5% silica and reduced to 21.5 MPa at 31%. The rLDPE-silica composite showed reduced tensile strength from 10.4 MPa for recycled HDPE to 10.2 MPa at 5% silica and an increase at 31% silica to 11.7 MPa. The modulus of elasticity for all the samples increased with the increasing silica content. The impact strength was found to increase from 5.6 kJ/m2 for pure PS - GPPS to 8.1 kJ/m2 at 5% silica. There was no remarkable increase in impact strength at 31% silica for PS-PPS. For HIPS composite, the impact reduced from 47 kJ/m2 for pure HIPS to 37 kJ/m2 at 5% silica and 11 kJ/m2 at 31% silica.

Thermal results of the composites at 31% silica were compared with pure respective polymers. In terms of thermal and mechanical properties, the general-purpose polystyrene had the highest heat absorption capacity and tensile strength. The modulus of elasticity was also reported highest in the general-purpose polystyrene composite. The results showed slight change in glass transition temperature and an increased heat absorption property when silica was added to respective polymers. Based on the results, natural silica (diatomite)-based composites may be used as green construction materials.
Fresh Air Flow Required to Maintain Safe Carbon Dioxide Levels and Provide a Breathable Air Environment in a Refuge Alternative
Authors: DeGennaro Cory , Yan Lincan , Yantek David
Published: January 2022

Federal mining regulations in the United States mandate that underground coal mines install refuge alternatives (RA) for miners to seek refuge after an inescapable disaster. RAs are required to isolate and protect occupants from hazardous conditions and to provide a life-sustaining, breathable air environment for a minimum of 96 hours. According to federal RA regulations, an RA’s oxygen levels (%O2) must be maintained between 18.5%–23% with carbon dioxide levels (%CO2) less than 1%. Once an RA is occupied, due to human breathing, the %O2 can decrease, and %CO2 levels can increase quickly. One method of providing an RA with a breathable air environment is to use a borehole air supply (BAS) to provide fresh air from the surface, purge existing harmful gases, and prevent harmful gas build-up. RA regulations require air supplies to provide air at 12.5 cubic feet per minute (cfm) per person. To investigate the minimum fresh air flow (FAF) rate needed to maintain interior %O2 and %CO2 within the mandated ranges, researchers conducted testing in a modified shipping container that represented the volume of an RA. During these tests, propane (C3H8) combustion and additional CO2 supplied from cylinders were used to match human O2 consumption and CO2 generation. The FAF rate supplied to the shipping container was varied to determine the minimum FAF rate required for the %CO2 inside the shipping container to stabilize below 1%. The test results showed that the minimum FAF rate was between 1.76–2.12 cfm per person. Therefore, the mandated per-person FAF rate provides a 6x–7x safety factor. Test results also showed that the %O2 range requirement was satisfied for the entire range of tested FAF rates from 1.76–12.5 cfm per person.

In this paper, researchers from the National Institute for Occupational Safety and Health (NIOSH) provide a repeatable test method that can be used to evaluate the FAF rate versus interior gas concentrations (%CO2 and %O2) for various occupancy levels to ensure a breathable air environment within a refuge alternative. This paper also discusses federal RA regulations and previous NIOSH research. Additionally, this paper provides an experimental concept and set-up description, including the C3H8 combustion and supplemental CO2 delivery with gas flow rates used to simulate human breathing, data collection sensors, laboratory modifications, and safety measures. Lastly, the paper discusses test results, including the amount of time taken to reach hazardous interior %CO2 and %O2, as well as %O2 and %CO2 resulting from several FAF rates that have been used to validate a predictive model. This test method could be adopted to evaluate breathable air environments in refuge alternatives and confined enclosures in various industries.
Resistance Heat Assisted Friction Element Welding
Authors: Grimm Tyler J. , Parvathy Gowtham V. , Mears Laine
Published: January 2022

The lightweighting of vehicle structures has become imperative in order to further improve efficiency within the transportation industry. One method of lightweighting is through the extensive use of multiple materials, offering the ability to selectively add strength where needed while eliminating the addition of extraneous mass. Though effective in design, multi-material automotive structures can be difficult to manufacture. One challenge which arises is the joining of these structures, which often cannot be achieved through traditional methods. Friction element welding (FEW) is a process capable of joining aluminum sheets to a steel substrate.

In this process, the aluminum material flows around the fastener shaft by applying an axial load and high rotational speeds. However, when joining high-strength aluminum alloys, this flow becomes diminished due to these materials’ relatively low ductility, resulting in the formation of sharp edges which protrude from the head of the fastener that introduce irregularities and potential contamination. These protrusions, termed chips, accelerate corrosion and are a significant defect. In a previous study, thermal assistance was confirmed as a viable method of reducing chipping by improving the flow of aluminum. An application method for such thermal assistance is developed and tested herein, which utilizes a direct electrical current applied locally to the joint region. The temperature rise was simulated and determined experimentally using a prototype modified downholder. Electrical heating was found to be a viable method of thermal assistance only when forced cooling of the electrodes is used.
Probabilistic Performance Evaluation and Optimization of Medical Plastic Moulded Components Subject to Large Scale Production
Authors: Brix Nerenst Tim , Ebro Martin , Nielsen Morten , Bhadani Kanishk , Asbjörnsson Gauti , Eifler Tobias , Lau Nielsen Kim
Published: January 2022

A new medical device can take years to develop from early concept to product launch. The long development process can be attributed to the severe consequences for the patient if the device malfunctions. Three approaches are often combined to mitigate risks: rigorous simulation and modeling, physical test programs, and Failure Mode Effect Analysis (FMEA) — all of which are time-consuming. Physical test programs are often carried out on prototype components from the same batch and, therefore, limited in revealing the actual distribution of performance. The risk probabilities are subsequently based on educated guesses. Furthermore, simulation and modeling are usually performed on nominal geometry — not accounting for variation — and only provide a safety factor against failure. The traditional use of safety factors in structural analysis versus the probabilistic approach to risk management presents an obvious misfit. Therefore, these three approaches are not ideal for addressing the two key questions that the design engineer has: 1) How often will the design fail, and 2) How should the design be changed to improve robustness and failure rates. The present work builds upon the existing Robust and Reliability-Based Design Optimization (R2BDO) and adjusts it to address the key questions above using finite element analysis. The key feature of the new framework is the focus on minimal use of computational resources while being able to screen feasible design concepts early in the embodiment phase and subsequently optimize their probabilistic performance. A case study in collaboration with a medical design and manufacturing company demonstrates the new framework. The case study includes FEA contact modeling between two plastic molded components with twelve geometrical variables. The optimization focuses on minimizing the failure rate (and improving design robustness) concerning three constraint functions (contact pressure, strain, torque). The study finds that the new framework achieves significant improvements to the component’s performance function (failure rate) with minimal computational resources.
Additively Manufactured Two-Phase Heat Exchanger Integrating PCMs for Spacecraft Thermal Management
Authors: Kabir Mehdi , Gemeda Takele , Preller Evan , Mohammed Raid , Xu Jiajun
Published: January 2022

For spacecraft thermal management systems, it is crucial to diminish the overall mass of on-board thermal storage system and minimize the temperature fluctuations when the environmental temperature changes drastically. Since there is no atmosphere in outer space, heat can only be rejected to space using radiation (e.g., radiators). By engaging and integrating phase-change materials (PCMs) into a passive two-phase heat exchanger, the radiator can be designed and sized for the average rather than the maximum power. To meet the NASA needs, the prototype developed and fabricated in the present study is a novel two-phase heat exchanger that integrates PCMs within a vapor chamber through multiple thin drawers loaded with bulk PCM. The entire solid structure of the prototype is manufactured additively using Maraging Steel with the Direct Laser Metal Sintering (DLMS) technique. The chosen working fluid is Methanol to undertake two-phase heat transfer via saturated vapor from the heated surface of evaporator to the condenser surface, and the condensate then returns back to the heated region and keeps recirculated using the capillary pumping pressure performed by the wick structure without any reliance on the gravitational magnitudes. Depending on the heat sink temperature and PCM melting temperature, the developed heat exchanger can either function as a thermal capacitor or a two-phase heat exchanger with thermal storage capability, that is, two modes of operation to be engaged within the spacecraft’s launching/landing stages or orbiting stage, respectively. In the present study, the geometry and number of the PCM-loaded drawers enclosed inside the heat exchanger’s casing are optimized based on the mass ratio (the ratio of PCM mass to the total heat exchanger mass), additive manufacturing (AM) constraints, and total thermal resistances imposed on the system for either of the operation modes.
Dynamic Response Evaluation of Platinum Thin Film Gauge
Authors: Alam Tanweer , Kumar Rakesh
Published: January 2022

The temperature gauge with quick response characteristic and ability to provide highly precise instantaneous temperature data is usually selected for the systems with minimal time available for the measurement. Thin-film gauges are best suited for such transient measurement. In this paper, the convective environment created by blower-heater arrangement is used to evaluate the dynamic response of platinum thin-film as a heat flux gauge. The in-house fabrication of the gauge is made by using quartz as a substrate and a thin-film of pure platinum acting as a sensing element. The response is measured to the step changes for the enforced convective heat flux. The heat flux value is inferred from transient temperature data from one-dimensional heat conduction model subjected to a semi-infinite body. Numerical analysis is also performed. The similarities of experimental and numerical results authenticate the experimental set up as well as the thin film gauge efficacy.
Verification of Additive Manufacturing Products Using Model Registration and Template Matching Techniques
Authors: Davis Lenning A. , Donnal John S. , Kutzer Michael D. M.
Published: January 2022

This paper presents a method of verifying Additive Manufacturing (AM) products using computer vision, specifically model based registration. The use of AM increasingly widespread, with systems being used by private households, educational institutions, commercial enterprises, and government agencies. With this increased adoption of AM comes cyber-physical risks and an ever-increasing potential for part defects. To address this growing issue, this method seeks to verify product quality using model-based registration and image comparison techniques. Using the “.gcode” file for a given part, and an estimate of the extruder’s pose relative to the product, we create a simulated image of the desired product. This simulated image can be compared to images of the physical part collected during the printing process to verify overall part quality. This paper presents two methods of image comparison to identify discrepancies. Preliminary results yield successful image segmentation and detection of structural defects.
Investigations to Consider Thermal Interactions Between Spatially Separated Subsystems: Concept of a Thermal Coupling System for X-in-the-Loop Test Benches
Authors: Leitenberger Felix , Steck Michael , Gwosch Thomas , Matthiesen Sven
Published: January 2022

The system behavior of new products can be validated with X-in-the-Loop (XiL) test benches. The potential spatial separation of the subsystems on those test benches interrupts the heat flows between the subsystems. This can lead to a different temperature distribution compared to the original assembly situation. It may change the system behavior because many functional relevant properties are temperature-dependent and the thermal interactions are not considered. The reliability of the test results concerning the system behaviour of the overall system is therefore reduced. This paper describes the investigations to consider thermal interactions between spatially separated subsystems on XiL test benches. A concept of a thermal coupling system for the transfer of thermal interactions by heat conduction is modeled. The model setup with sensors, actuators and control systems is described in detail. A simulation is used to check its feasibility for a future physical setup. The results of the simulation show small temperature deviations compared to the situation with spatially separated subsystems. With such a thermal coupling system, thermal interactions by heat conduction between spatially separated subsystems can be transferred. It is able to improve the product validation by using it on XiL test benches.
Yttrium Decorated on Thin Borophene Defect for Hydrogen Storage: A First Principles Study
Authors: Ledwaba Kabelo , Karimzadeh Sina , Mkhohlakali Andile , Jen Tien-Chien
Published: January 2022

Borophene- two-dimensional (2D) is an emerging material that has engrossed much consideration in the field of energy materials They exhibit a broad range of various incredible properties, which were considered as ground-breaking for different application such as batteries, superconductors, anode materials for photochemical water splitting, and biosensors and super capacitors. Yttrium-decorated borophene (Y-borophene) as a carrier for hydrogen storage have been studied. DFT calculations based on the Dmol3 code were used to investigate adsorption energy and optimal geometry for hydrogen adsorption on pure borophene and Y-borophene. Isolated yttrium atom on borophene have studied for defect. For Y-borophene, the yttrium atom can adsorb eight hydrogen molecules with average adsorption energy of 0.461 eV/H2 which has increased adsorption energy by 33% compared to the pure borophene with the same condition. The hydrogen storage capacity of this material is 15.23 wt.%, demonstrating Y-borophene as a promising candidate for hydrogen storage. In addition, the density of states plots (PDOS) is presented to further comprehend the electronic structures and bonding nature.
Effect of Cyclic Compression on Mechanical Behavior of Ceramic-in-Polymer Composite Electrolytes for Lithium-Ion Batteries
Authors: Mulay Nishad , Oh Dahyun , Yoon Dan-Il , Lee Sang-Joon (John)
Published: January 2022

Composite polymer electrolytes (CPEs) for lithium-ion batteries provide an effective balance of ionic conductivity, mechanical robustness, and safety. Loss of charge capacity, however, is caused by several contributing factors. In this work we specifically examine mechanical changes in the composite electrolyte layer. We apply cyclic compression to mimic stress cycling that is caused by asymmetric volume changes during charging cycles between anode and cathode. Using a representative composite electrolyte formulation consisting of Li6.4La3Zr1.4Ta0.6O12 (LLZTO) at 10 wt. % in polyethylene oxide (PEO) with bis(trifluoromethane) sulfonimide (LiTFSI), we experimentally measure stress-strain characteristics, stress relaxation time, and cyclic compression of a composite electrolyte. We also examine the effect of particle size, by comparing 500 nm vs. 5 μm sizes. At 15% compressive strain, the addition of 500 nm particles increased strain energy density (SED) by a factor of 2.6 and the addition of 5 μm particles increased SED by a factor of 2.9. Both particle sizes showed similar relaxation time constant, but the 5 μm particles showed tighter repeatability than the 500 nm case. Both compositions exhibited continual decline in peak stress beyond 500 cycles of compression at 15% strain. These experiments reveal insights into how cyclic loading can alter the mechanical response of a composite electrolyte, and thereby contribute to the broader understanding of electrochemical and mechanical coupling in lithium-ion batteries.
Conceptual Design of Temperature-Controlled Fueled-Salt Irradiation Experiment to Support Demonstration of Advanced Nuclear Reactors
Authors: Abou-Jaoude Abdalla , Chandler James , Core Gregory , Davies Kim , Downey Calvin , Phillips William , Tan Chuting , Wilson Stacey
Published: January 2022

Irradiation testing of fuel-bearing molten salts is critical for supporting the development and demonstration of molten salt reactors (MSRs). These experiments can inform several important reactor design and safety parameters, including source term modeling, the evolution of thermophysical properties with burnup, and the degradation of structural materials under reactor-relevant conditions. Idaho National Laboratory is designing an instrumented and heated high-temperature molten-salt-fueled irradiation capsule to study the behavior of the fuel salt during in-pile irradiation. This paper details the neutronics, thermal, and mechanical analyses performed to date. Parametric studies were performed to assess a range of materials, different experiment dimensions, two in-reactor positions, and the fuel enrichment used. The principal recommendations are to select a peripheral reactor position in order to alleviate neutronic constraints, a thin salt annulus to achieve thermal design objectives, and high-temperature alloys that provide additional safety margins.
Valve-Enabled Sample Preparation and Isothermal Amplification for SARS-CoV-2 Detection at the Point-of-Care
Authors: Manzanas Carlos , Alam Md. Mahbubul , Loeb Julia C. , Lednicky John A. , Wu Chang-Yu , Fan Z. Hugh
Published: January 2022

Early and accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the point-of-care (POC) is crucial for reducing the transmission of coronavirus disease 2019 (COVID-19). To address this need, we have developed a valve-enabled lysis, paper-based RNA enrichment, and RNA amplification device (VLEAD) for detecting SARS-CoV-2. We have combined VLEAD with a smart coffee mug for sample preparation, nucleic acid isothermal amplification, and colorimetric detection using a smartphone camera or a naked eye. VLEAD enables two critical functions required for POC testing: sample preparation and detection. Since the reagents can be pre-packaged in the device, all operational steps can be carried out at POC. We have demonstrated the functions of the device by analyzing samples spiked with heat-inactivated SARS-CoV-2, which were obtained from BEI Resources. This rapid and highly sensitive POC platform for SARS-CoV-2 detection has a potential to help reduce COVID-19 transmission.
A Hybrid Methodology for Risk Mitigation During Development of Safety-Critical Autonomy Features
Authors: Zarifian Pez , Garikapati Divya , Pralle Julia , Dawson Jennifer , Hubmann Constantin , Reiff Brielle , Tam Raymond , Gaddamadugu Gopi
Published: January 2022

As a relatively nascent field, engineers developing autonomous vehicle (AV) technologies need frequent performance feedback on whether algorithms are performing the driving task competently. Further, because of the complexity of AV systems, it is often lower risk to frequently test small, incremental changes instead of delaying testing and accumulating a large number of changes to the algorithms. While simulation and closed course testing are useful and critically important tools, ultimately driving on public roads is necessary to truly understand system performance and identify potential edge cases. Maintaining a high safety standard to protect all road users during continual public road testing is of paramount importance for the AV industry.

The Waterfall methodology has a demonstrated track record for product safety, but does not provide much flexibility for prototyping and incremental testing. The Agile methodology is famous for enabling rapid development and incremental rollouts, but does not possess any inherent safety gates. When it comes to developing complex safety-critical autonomy features, particularly for dynamic environments such as in the case of autonomous vehicles, neither method is fitting.

This paper presents a hybrid methodology that strikes a balance between safe and rapid development of autonomy features for the AV industry.
Innovation in Hydrotesting Above Ground Pipes: Analytical Solution via Integral Transforms for Discerning Test Fluid Temperatures Subject to Ambient Temperature Variations
Authors: Isaza Pedro A. , Botros Kamal K.
Published: January 2022

Hydrostatic testing for strength and leaks of newly constructed pipelines are required by code. However, for exposed pipes challenges are encountered since ambient conditions can influence pressure responses. Additionally, there is uncertainty as to whether the temperatures measured at a pipe’s outer wall, which are used to compute the expected pressure profiles, are representative of the testing fluid. To help bridge the gap, this work demonstrates the use of integral transforms for analytically solving the non-homogeneous 1D transient equations prescribed for the fluid temperature inside a cylindrical pipe. The solution identified provides sufficient generality to accommodate arbitrary initial conditions and ambient temperature variations. Furthermore, a rate of change function is formulated which enables a direct assessment of the temperature equality assumption between the fluid and the pipe wall. The validity of the solution is then substantiated by demonstrating excellent agreement with results reported in the literature (for a scenario describing typical hydrotest conditions). From the results obtained it can be observed that as the Biot number increases the temperature equality assumption begins to break down. Finally, a simplified expression for the relationship between the rate of change of the ambient air and the average fluid temperatures was formulated for this special scenario, which again showed agreement with the results in the literature.
Modular Printed Powered Air Purifying Respirator
Authors: Brown J. , Clifford M. , Magana J. , Salman M. , Tran D.
Published: January 2022

At present, the world is undergoing a pandemic spawning from the advent of a new coronavirus outbreak known as COVID-19. As a result, hospital staff, paramedics, first responders, and the general world population have been forced to wear personal protective equipment (PPE) and take special measures to prevent catching the virus. Furthermore, because of this necessity, increasing demand on the PPE supply chain has generated many shortages, especially seen in masks designed to stop the inhalation of COVID-19 particles in the air. This inspired our group to design something that could help make PPE more accessible and affordable for the average person. The proposed is an almost entirely 3D printed design to help keep costs down and make it simplistic, such that anyone with a 3D printer has the potential to duplicate it. We hope that with the design, we can help combat the shortage and keep more people safe from COVID-19.
Anomaly Detection for Cyber-Physical Systems Using Transformers
Authors: Ma Yuliang , Morozov Andrey , Ding Sheng
Published: January 2022

Safety and reliability are two critical factors of modern Cyber-Physical Systems (CPS). However, the increasing structural and behavioral complexity of modern automation systems significantly increases the possibility of system errors and failures, which can easily lead to economic loss or even hazardous events. Anomaly Detection (AD) techniques provide a potential solution to this problem, and conventional methods, e.g., Autoregressive Integrated Moving Average model (ARIMA), are no longer the best choice for anomaly detection for modern complex CPS. Recently, Deep Learning (DL) and Machine Learning (ML) anomaly detection methods became more popular, and numerous practical applications have been presented in many industrial scenarios. Most of the modern DL-based anomaly detection methods use the prediction approach and LSTM architecture. The Transformer is a new neural network architecture that outperforms LSTM in natural language processing.

In this paper, we show that the Transformer-based deep learning model, which has received much attention recently, can be applied to the anomaly detection of industrial automation systems. Specifically, we collect time-series data from a system of two industrial robots using a Simulink model. Then, we feed these data into our Transformer-based model and train it to be a time-series data predictor. The paper presents the experimental results that show the comparison of precision and speed of a Long-Short Time Memory (LSTM) predictor and our Transformer-based predictor.
Performance Analysis of a Gas Turbine Disk Containing Rotating Heat Pipes
Authors: Lu Wanqiu , Ding Shuiting , Li Guo
Published: January 2022

The turbine disk is a key component of an aero-engine, which works under extremely high rotational and thermal loads. The combination of high-temperature heat pipes with a turbine disk is an effective method for controlling thermal load and the corresponding stress level because heat pipes enable rapid heat transfer from the rim of the disk to its hub. In this study, the influences of temperature and stress distribution variations caused by two different shapes of heat pipes are evaluated via thermomechanical finite element simulation. Results show that although the two shapes of heat pipes exert minimal effect on temperature change at the rim, specially shaped heat pipes with a connection ring at the bottom exhibit an advantage over cylindrical heat pipes in terms of stress level decrease at the hub of the disk because the former have lower rotational and thermal hoop stress components. Moreover, notch stress at the end of the heat pipe condenser is associated with the geometric parameters of heat pipes, particularly heat pipe length.
Unstart Phenomena Induced by Forced Excitation in a Dual-Mode Scramjet
Authors: Alex Alvin , Lijo V.
Published: January 2022

Scramjet engine with no moving parts and extensive speed range is suitable for developing cheaper vehicles to outer space. The isolator, which isolates the inlet from the pressure buildup inside the combustor, is a critical component of the scramjet engine. In an actual scramjet, the combustor undergoes highly transient combustion giving rise to high amplitude fluctuating backpressure, which may cause the inlet to unstart. In general, combustion in a scramjet is a complex process that involves flows subjected to considerable pressure gradients, coexisting subsonic and supersonic flow regions in the presence of shock waves. Moreover, shock-induced boundary-layer separation patterns are different due to asymmetrical boundary layer development at the walls. Until now, no experimental study on the forced dynamic excitation in hypersonic flows is reported, mainly due to the limited available ground facilities that can reproduce such conditions. Such dynamic excitation can give to flow fields that are significantly different from that reported in other studies. The present study numerically addresses forced excitation inside the combustor generated by an elliptical-shaped rotor. During the unstart process, several stages were identified, such as separation and its growth in both the upper and lower walls of the combustor, isolator, inlet, and finally, shock excursion leading to unstart. The results provide ample insight into the upstream propagation of flow disturbances originating from the combustor, its interaction with the asymmetric boundary layers on top and bottom walls, and the dynamics of inlet unstart.