bluuebunny/crossref_metadata_2025_split huggingface dataset:
Virtual Testbed for Economical and Reliability Analysis of Battery Thermal Management Control Strategies
Authors: Singh Sagar , Olyaei Mostafa , Jiang Katherine , Gurumukhi Yashraj , Goodson Kenneth , Asheghi Mehdi , Miljkovic Nenad 
Published: November 2023

Abstract
A virtual testbed simulation framework is created for the economical and reliability analysis of battery thermal management control strategies in electric vehicles (EVs). The economic benefit of extending battery lifetime by optimal thermal conditioning is weighed against the corresponding energy cost of the operation, allowing for the adoption of economy-conscious strategies under different conditions. The system-level model is created in the MATLAB environment using the Simscape library and custom components as required. A lumped-parameter coupled electro-thermal model with temperature and state of charge dependent cell parameters is adapted from the literature to characterize battery performance. Suitable cell capacity degradation models are implemented to capture the cycle aging and calendar aging of the battery. Active cooling of the battery using a refrigerant system along with a preconditioning strategy is benchmarked against passive cooling by a radiator for operating cost, battery lifetime, and net savings. Active cooling can maintain optimal battery temperature but requires an additional 90–200 $/year in electrical costs compared to passive cooling. However, this cost is more than compensated for by the increase in battery lifetime by 1.5–3.2 years leading to a net savings of 325–1100 $/year.
Performance of SAC305 Solder Joints Under Simultaneous Tensile and Electromigration Stressing
Authors: Vinson Whit , Huitink David 
Published: November 2023

Abstract
The results contained within this paper examine the combined influence of electromigration stressors (elevated current density and elevated ambient temperature) and tensile stress on the lifetime of SAC305 solder joints (300[μm] diameter) compared to either individual stress condition acting singularly. Tensile stresses of 0 to 5 [MPa] were applied to samples already experiencing electromigration conditions of 9,100 [A/cm2] (4.611 [A]) at ambient temperatures of 100 and 150 [°C]. The testing duration was limited to 48 hours per sample. All samples tested without an applied tensile stress (i.e. 0 [MPa]) survived the 48 hour period. The same was true for only five of 24 samples tested under combined electromigration and tensile stressing conditions. Post failure analysis of the samples tested under combined electromigration and tensile stress showed necking or breakage at the Cu/SAC305 interface on the upstream side of electron flux. Cross-sectional analysis of tested samples is consistent with findings from other studies regarding electromigration failure in Cu/SAC305/Cu solder joint assemblies, where the intermetallic regions at Cu/SAC305 interfaces grow asymmetrically. Inherent process-voids in the experimental samples are discussed as a source of error and a brief computational examination of the impact of process-related voiding on current density and self-heating within solder samples is provided.
Predictive Modeling of High-G Potted Assemblies With Fine Pitch Electronics After Sustained High-Temperature Exposure
Authors: Lall Pradeep , Pandurangan Aathi Raja Ram , Blecker Ken 
Published: November 2023

Abstract
Electronic components designed for commercial purposes are subjected to high G shock loads and thermo-mechanical loads in defense and aerospace applications, making reliability a crucial factor in these harsh environments. To improve the reliability of printed circuit boards in such applications, they are potted, but interfacial delamination at the potting/PCB interface remains a major failure mode. The interfacial properties of the potting/PCB interface evolve over time with sustained exposure to high temperatures, which makes it necessary to investigate the effects of such exposure on the interface properties. The present study focuses on investigating the evolution of interfacial properties at the potting/PCB interface with respect to high-temperature exposure and the use of restraint mechanisms. A circular printed circuit board with fine-pitch electronic packages and multilayer ceramic chip capacitors is assembled, and bimaterial specimens of potting/PCB are made to investigate the evolution of interfacial properties. The specimens are tested under four-point bend loading, and the interfacial fracture toughness properties and cohesive zone parameters are determined for each of the interfaces. Additionally, potted circular printed circuit boards with four different potting materials are tested for pristine and 90-day aging at 150°C. The boards are subjected to shock levels of 10,000g and 25,000g to evaluate the efficacy of the potting compounds on the solder joint reliability of fine-pitch electronics and large discrete components. The study investigates an aspect of potting electronics that has not been reported earlier and could have practical implications for manufacturers. The cohesive zone parameters obtained from the bi-material samples are validated and used to develop a predictive finite element high G shock model for the circular board assemblies. The experimental test conditions are validated with the predictive model output to provide a better understanding of the interfacial properties of the potting/PCB interface. The study also discusses the potential use of the predictive model in the design of electronic components for harsh environmental applications. In summary, the study investigates the evolution of interfacial properties at the potting/PCB interface with respect to high-temperature exposure and the use of restraint mechanisms. The study also evaluates the efficacy of different potting compounds on the solder joint reliability of fine-pitch electronics and large discrete components for various aging durations. The cohesive zone parameters obtained from the bi-material samples are validated and used in the development of a predictive finite element high G shock model. The study could have practical implications for manufacturers designing electronic components for harsh environmental applications, and it provides valuable insights into the interfacial properties of the potting/PCB interface.
Study of Flow-Dependent Characteristics of HFE 7500 Coolant Dielectric Strength
Authors: Tunon Bryan , Huitink David 
Published: November 2023

Abstract
The use of dielectric fluids in direct cooling techniques offers an opportunity to address the thermal demands of highpower electronics that current external-to-case methods are struggling to meet. However, limited understanding about the voltage isolation performance of these fluids under different flow conditions limits their application. This effort seeks to understand the flow-dependent behavior of dielectric fluids, specifically of HFE 7500, when applied in force convective cooling method. To help understand this behavior, the flow characteristics of the dielectric fluid flowing over a needle-to-needle electrode configuration are compared to the partial discharge behavior when high voltages are applied. First, partial discharge data is collected for different flow rates in a closed flow loop containing the test section with the electrodes separated by a gap of 1 mm. Next, the test section is slightly pressurized to measure breakdown voltage and partial discharge on the dielectric fluid. The initiation of vortices due to flow over the needle configuration past a certain flow range creates low pressure zones that periodically detach from the electrodes. These low-pressure zones could impact the dielectric strength of the fluid as seen in the increased partial discharge rate for certain flow regimes. A lower breakdown voltage of HFE 7500 is observed when negative static gauge pressures are maintained in the test chamber, further supporting this hypothesis.
Development of Thermal Metrology Standards for Experimental Characterization of Thermal Resistance for Single-Phase Liquid Cold Plates
Authors: Ortega Alfonso , Martinez Victor A. , Caceres Carol , Heydari Ali , Chowdhury Uschas 
Published: November 2023

Abstract
Over the last decade, a significant number of investigations have been performed to develop and optimize cold plates for direct-to-chip cooling with cold plates attached to processor packages. Many investigations have reported computational simulations using commercially available CFD tools that are compared to experimental data. Generally, the simulations and experimental data are in qualitative agreement but often not in quantitative agreement. The computational simulations are used for thermal and hydraulic characterization of these cold plates and are used to perform parametric analysis to address the cold plate’s optimal design. Unfortunately, the experimental characterizations have high uncertainty due to lack of proper attention to the basic measurements, particularly of temperature. Extensive experimental evaluations reported in this paper will be used to demonstrate the frequent errors in experimental thermal measurements used in forming the defined thermal resistance and the experimental artifacts during testing that lead to unacceptable inconsistency and uncertainty in the reported results. By comparing experimental thermal data such as the temperature at multiple points on the processor lid, and using that data to extract a meaningful measure of thermal resistance, it will be shown that the data uncertainty and inconsistency is primarily due to three factors: (1.) inconsistency in the thermal boundary condition supplied by the TTV to the cold plate; (2.) errors in the measurement and interpretation of the surface temperature of a solid surface, such as the heated lid surface or the base of the cold plate, and (3.) errors introduced by improper contact between cold plate and TTV. A standard thermal test vehicle (STTV) was designed and used to provide reproducible thermal boundary conditions to the cold plate. An uncertainty analysis was performed in order to discriminate between the sources of inconsistencies in the reporting of thermal resistance, including parameters such as mechanical load distribution, methods for measuring the cold plate base, and TTV surface temperatures.
Quick Turn Methodology for High Temperature Solder Fatigue Reliability
Authors: Norris Matthew , Huitink David 
Published: November 2023

Abstract
Coefficient of thermal expansion (CTE) mismatch is responsible for most of the failures experienced in electronics packaging. Traditional means of life testing include thermal shock, thermal cycling, and power cycling; however there are several drawbacks to these methods. Thermal shock produces high thermal gradients which can present inaccuracies in time to failure (TTF) calculations through inconsistent fatigue behavior. Power cycling is the fastest of the three methods at cycling rates of up to 6 cycles per hour, which minimizes the time that a test can be observed during a standard workday/week. All of the processes require a large amount of power either through the repetitive heating and cooling of an oven, or the power dissipated by the electronics themselves, leading to unnecessary energy expenditures. Since these tests need to be performed for any given geometry and material, a more efficient test method was required. By equating CTE mismatch to mechanically cycled fatigue testing the lifetime of the sample can be approximated with at least a 10x reduction in TTF, as proposed by [1]. This allows for materials to be decoupled from a system and tested individually at cycle rates up to 1 cycle per second. We present a comparison of different lead-free solders using this accelerated test method. The test involves utilizing a modified tribometer to apply a sinusoidal force with peaks of ±20 N to a soldered sample using spring displacement according to Hooke’s law. Elevated temperature testing was utilized, at a homologous temperature of 0.8, to further accelerate TTF, in increasing the contribution of plasticity where the solders accumulate a significant amount of work per cycle without risk of reflow. As lead-free solder and solder pastes become more popular, a solid characterization of different attachment materials is required to make an informed selection for cost effectiveness versus robustness in a design. In this paper, we examined three different compositions. The control sample of gold-tin (AuSn) solder was used to compare against tin-antimony at compositions of 90:10 (Sn90Sb10) and 95:05 (Sn95Sb5). The footprint geometry was kept constant across all samples. Post failure, the mode of failure was examined via visual inspection under optical microscope and SEM imaging. The microhardness of samples was then captured in different regions confirming variation between hardness experienced by locations of different failure modes. Additionally, due to process, voiding was present in many samples. This voiding was examined and found to be inversely proportional to life, leading to a better understanding of the importance of process control.
Investigation of Performance and Repairability of Additively Printed Functional Circuits With Water-Based Silver Ink on an Inkjet Platform
Authors: Lall Pradeep , Kulkarni Shriram , Miller Scott 
Published: November 2023

Abstract
Additive printing techniques, particularly inkjet printing, have gained significant traction in the manufacturing of electronic circuits due to their cost-effective and time-efficient nature. Inkjet printing offers several advantages over traditional methods like screen printing, including printing fine lines and utilizing a broader range of conductive inks. Water-based silver ink is an environmentally friendly and highly conductive option. The water-based formulation eliminates the need for toxic solvents, ensuring a safer manufacturing and disposal process. This paper focuses on evaluating the performance of functional circuits additively printed with water-based silver ink using an inkjet platform. The circuits were printed onto a flexible Polyimide substrate using an inkjet printer with a piezoelectric printhead. Functional circuits comprising High-Pass and Low-Pass Signal Filters were printed using water-based silver ink, with discrete commercial-off-the-shelf (COTS) components attached. The frequency response of these circuits was measured and compared to simulated responses to determine any deviations in electrical performance. The viability of repairing printed circuits was studied by intentionally detaching and reattaching the components. The repaired circuits were then compared to the pristine circuits in terms of their electrical performance.
The Dual Role of “Coffee-Ring“ Effect in Colloidal Microchannel Formation
Authors: Dumont Ryan , Thammisetty Spandana , Li Bo 
Published: November 2023

Abstract
In order to address the challenges presented by future electronics with complex functionality and architecture, new materials and fabrication methods must be developed. In contrast to traditional top-down approaches, bottom-up self-assembly has emerged as a robust means of organizing nanoscopic building blocks into highly ordered structures and materials. In particular, topographical micropatterns are typically fabricated using complicated lithographic methods that are expensive and time-consuming and not suitable for high throughput manufacturing. Colloidal cracks, also known as colloidal microchannels, have been identified as a simple and robust strategy for the fabrication of scalable microchannels. Despite extensive theoretical modeling to understand the mechanism of crack formation, the influence of the “coffee-ring” effect on crack formation remains largely unexplored. Herein, we explore how the “coffee-ring” effect determines the colloidal microchannel formation by leveraging the kinetic control of the non-equilibrium deposition process of PS latex nanoparticles. Surprisingly, by tuning the particle size, we found the “coffeering” effect plays a dual role in determining the colloidal microchannel formation. In addition, temperature-concentration phase diagrams of colloidal microchannel formation are also provided in this work. Overall, the study presented offers crucial insights into controlling the self-assembly of colloidal particles to form microchannels, which is essential for the low-cost and large-scale fabrication of topographical templates. This study has important applications in microfluidics, geometry confinement for functional materials deposition, and alignment.
Evaluation of Antibacterial Activities for Poly-DL-Lactic Acid Nanosheet on the Biomimetic Sharkskin
Authors: Nakano Shunsuke , Ananthan Alyssa Asong , Ibrahim Mohd Danial , Abang Mahmod Dayang Salyani , Awang Husain Awang Ahmad Sallehin , Ngieng Ngui Sing , Sunami Yuta 
Published: November 2023

Abstract
The purpose of this study is to quantitatively examine whether antimicrobial activity varies with the thickness of the PDLLA nanosheets when placed on a PDMS surface with or without biomimetic shark skin surfaces. Sharks are known to have an antifouling property due to the rivulet structure of grooves spaced tens of μm apart covering their skin. The riblet structure reduces the area to which organisms adhere and prevents contact with small dirt and bacteria. In this study, a PDMS elastomer-embedded stamping method consisting of polydimethylsiloxane PDMS was used to achieve the biomimicry of sharkskin. The surface morphology before and after the nanosheet was applied was then observed with a scanning electron microscope to create a bacterial mass reference line to evaluate its antimicrobial activity. As a result, a decrease in antimicrobial activity was observed in the biological model compared to the flat surface. In addition, a small decreasing trend in antimicrobial effect was seen when the film thickness exceeded 100 nm in nanosheets with different film thicknesses, indicating that the antimicrobial activity on the surface increased as the film thickness became thicker and less able to follow the surface irregularities.
Integrating Multivariate Signal Processing and Machine Learning for Optimal Control of Prosthetic Hands
Authors: Pirouz Mortaza , Tadesse Yonas 
Published: November 2023

Abstract
Control systems for prosthetic hands, actuated with muscle-like actuators face challenges in achieving natural and intuitive movement. The utilization of electromyography (EMG) has the potential to control wearable devices and establish a connection between the human body and smart devices. Although this holds a great promise, there are still challenges to be addressed. Accurately replicating control signals from nerve and muscle sources is significant due to the complexity of signals and the high noise-to-signal ratio. This must be effectively addressed to ensure precise control of the robotic hand, prior to implementing artificial intelligence for the creation of smart devices. To address these challenges, we utilized EMG dataset comprising 8 channels, having 15 different hand motions, with 24 trials (8 individuals with 3 repeated measurements), and 20 seconds of data for each trial. The dataset was sampled at a rate of 4000 samples per second. We used Generalized Eigendecomposition (GED) technique to isolate and distinguish various sources of naturally occurring signals in the human arm, simultaneously reducing the noise ratio. Subsequently, these processed signals are then employed to train machine learning models for movement recognition, imitation learning, and adaptive control. Our machine learning algorithms trained using GED achieved exceptional accuracy in recognizing unprocessed EMG signals. For individual data, we achieved 100% accuracy, while for combined training and testing data from multiple individuals, the accuracy reached over 83%. Notably, our approach outperformed convolutional neural network models on the same dataset in terms of both speed and accuracy. These results highlight the effectiveness of employing multivariate signal processing techniques, such as GED, in improving accuracy, reducing overfitting, and enhancing the robustness and reliability of predictions. These findings have significant implications for optimizing the control of prosthetic hands.
Design Optimisation of a Planar Electromagnetic Energy Harvester Suitable for Low Frequency Vibrations
Authors: Ghafoor Nouman , Punch Jeff , Nico Valeria 
Published: November 2023

Abstract
Nowadays, most of the wireless sensor nodes (WSNs) used in Internet of Things (IoT) applications are powered by batteries. Despite the convenience of battery usage, the need for frequent battery replacement contributes to both direct and indirect environmental pollution. Vibrational energy harvesting using electromagnetic vibrational energy harvesters (EM-VEHs) is a more sustainable alternative to batteries as it harnesses the kinetic energy from ambient vibrations. Usually, the form factors of these devices render them difficult to integrate with printed circuit board and energy storage technologies since coils and magnets are generally arranged in a cylindrical form factor. Arranging coils and magnets in a planar configuration can result in a more compact device and improved integration.
In this paper, an innovative planar EM-VEH design is proposed for harvesting kinetic energy from low frequency (10 Hz to 20 Hz), in-plane vibrations. The structure comprises three fixed-free beams, each of which is fixed on one side to the housing of the harvester while their free ends are attached to a single mass that acts as a magnet holder. Compared to previous studies where the beams are straight (90° to the mass and to the fixed ends), the proposed fixed-free beams form an angle (86°) to the mass and at the fixed end. Coils can be placed on top and bottom of the magnets or, in case of a Halbach array, coils can be placed on top or bottom of the magnets. In-plane excitations induce oscillations of the beams in the in-plane direction and, hence, relative movement of magnets and coils.
Finite element analysis (FEA) using the stress and frequency analysis modules in SolidWorks was carried out to investigate and optimise different geometrical parameters of the design in order to increase the output power for low amplitude (up to 0.5 g, g = 9.81 m/s2) and low frequency (up to 20 Hz) vibrations. In particular, geometrical dimensions of the beams are optimised in terms of: (1) stress at the fixed end of the beam; (2) vertical deflection of the mass at free end; and (3) the movement of the magnet holder.
The FEA results show a resonant frequency of 16.8 Hz, and relative displacements in x-axis of coil and magnet of 4.3 mm, 6.5 mm, 8.7mm and 10.8 mm at acceleration levels of 0.2 g, 0.3 g, 0.4 g, and 0.5 g, respectively.