bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards Physically Talented Aerial Robots With Intelligent Swarm Behavior Thereof: an Efficient Co-Design Approach
Authors: KrisshnaKumar Prajit , Paul Steve , Manjunatha Hemanth , Corra Mary , Esfahani Ehsan , Chowdhury Souma
Published: November 2024

The collective performance or capacity of collaborative autonomous systems such as a swarm of robots is jointly influenced by the morphology and the behavior of individual systems in that collective. In that context, this paper explores how morphology impacts the learned tactical behavior of unmanned aerial/ground robots performing reconnaissance and search & rescue. This is achieved by presenting a computationally efficient framework to solve this otherwise challenging problem of jointly optimizing the morphology and tactical behavior of swarm robots. Key novel developments to this end include the use of physical talent metrics and modification of graph reinforcement learning architectures to allow joint learning of the swarm tactical policy and the talent metrics (search speed, flight range, and cruising speed) that constrain mobility and object/victim search capabilities of the aerial robots executing these tactics. Implementation of this co-design approach is supported by advancements to an open-source Pybullet-based swarm simulator that allows the use of variable aerial asset capabilities. The results of the co-design are observed to outperform those of tactics learning with a fixed Pareto design, when compared in terms of mission performance metrics. Significant differences in morphology and learned behavior are also observed by comparing the baseline design and the co-design outcomes.
Investigating Mechanical Behavior of 3D Printed Compliant and Origami-Inspired Mechanisms
Authors: Parkinson Bethany , Martel Austin , Wing Davis , Magleby Spencer
Published: November 2024

The fused filament fabrication 3D printer is growing in popularity amongst designers. When manufacturing actuating mechanisms, however, it can often be difficult to use 3D printers to achieve desired behavior. Two essential areas of active mechanisms — compliant mechanisms and origami-based mechanisms — are explored in this paper.

The design of compliant mechanisms for specific applications often requires them to achieve specific kinetics, which necessitates knowledge of material and mechanical properties. When 3D printing with polymers, mechanical properties vary widely based on a variety of factors, including process parameters. Through a thorough study involving systematically changing several parameters of the slicer and performing a three-point bending test on a 3D printed specimen, mechanical properties for a variety of parameters are recorded. These tests indicate that compliant mechanisms can be 3D printed from polymers to achieve desired mechanical properties from the mechanism.

Manufacturing origami-inspired mechanisms often requires assembly, where precise alignment of panels is essential. Through changing process parameters, thickened origami flashers and patterns may be 3D printed in a single operation, thus eliminating the need for assembly. This is achieved through designing compliant living hinges into the 3D model and altering process parameters to ensure that these hinges are flexible and durable.

Through using these process parameters and test results or through applying the framework presented here with their own 3D printer or material, designers can more effectively use 3D printing to design and rapidly prototype compliant mechanisms and origami-inspired mechanisms.
ConceptVis: Generating and Exploring Design Concepts for Early-Stage Ideation Using Large Language Model
Authors: Duan Runlin , Karthik Nachiketh , Shi Jingyu , Jain Rahul , Yang Maria C. , Ramani Karthik
Published: November 2024

Large language models (LLMs) are capable of generating cross-domain design knowledge, opening up new possibilities for creating a myriad of design concepts for early-stage design ideation. The current interfaces and interaction capabilities of LLMs, however, pose challenges in controlling the ideation process in terms of its diversity and quality. To enhance human guidance over the LLM-driven ideation process, we have developed ConceptVis, a system that organizes and symbiotically coordinates the LLM-generated design space through an interactive knowledge graph. In ConceptVis, designers can easily control the breadth and depth of the design space by intuitively prompting the LLM from the graph nodes. Natural Language Processing (NLP) algorithms extract concept keywords and related design knowledge from LLM responses, which are then added to the knowledge graph for visualization. We conducted a user study with 24 novice designers and compared the performance of ConceptVis with that of a chat-based LLM interface for concept generation. With ConceptVis, designers can explore the design space with a balance of breadth and depth. This approach prevents them from merely prompting the LLM to generate random concepts, struggling to keep track of what has been generated in long linear lists, or fixating on early ideas. Supporting users to interact with LLMs through an interactive visual interface significantly improves both the efficiency and quality of concept generation. This result highlights the importance of developing user-centered design systems to facilitate human-LLM collaboration during the early stages of design.
Transitioning Towards Circular Consumer Electronics Products
Authors: Ko Junwon , Guedes Gisele Bortolaz , Badurdeen Fazleena , Jawahir I. S. , Morris K. C. , Ferrero Vincenzo
Published: November 2024

In the present digital era, consumer electronics have become ubiquitous, providing numerous conveniences in various aspects of daily life. However, the significant increase in the production and use of consumer electronics products coupled with the unplanned end-of-life management leads to the depletion of rare earth materials, increasing carbon emissions, and growing electronic waste, thus presenting unique sustainability challenges. Numerous studies have emphasized the development of circular electronic products that align with Circular Economy principles to address these issues. Consumer electronics industry-led initiatives, such as the Circular Electronics Partnership (CEP), have also made a concerted effort to establish key requirements to ensure the circular flow of consumer electronics. However, the broadness of these requirements poses challenges in operationalizing them to facilitate more effective decision-making during product design. This paper addresses this gap by proposing more specific and actionable circular product attributes identified and compiled from extant literature. The relevancy of these attributes was verified in consultation with industry practitioners. These attributes were then mapped to the broad, generic requirements proposed by the CEP. By doing so, this research contributes to translating the CEP-proposed requirements into more specific and actionable attributes to facilitate the design and manufacturing of circular products in the consumer electronics industry.
Review of Commercial One-Dimensional Thermo-Fluid Solvers for Liquid Cooled Server System
Authors: Ravi Bharath Ram , Yu Jiwon , Keefe Stephen , Chu Herman , Wealther Chase
Published: November 2024

Recent advancements in Artificial Intelligence (AI), blockchain, the Internet of Things (IoT), and other technologies have driven the development of high-performance server systems. This progress has resulted in a significant increase in heat dissipation of servers, limiting the use of traditional air-cooling methods. Many high-performance server systems currently available in the market require liquid cooling due to their high power and power densities. Liquid cooling technologies provide a more efficient means of dissipating heat from high-power density chips and, in certain cases, can lead to reduced operating costs and carbon footprint for data centers. This study focuses on evaluating two commercially available one-dimensional thermo-fluid analysis tools by comparing their results with experimental data. The liquid cooling system under examination consists of a single coolant loop branching into two sections. Each section contains a cold plate designed for a CPU chip and ten cold plates dedicated to cooling DIMM modules. Both one-dimensional solver tools demonstrated good correlation with the experimental results. The study also discusses the limitations of the options available in these tools for modelling flow and heat transfer components.
Behavior of Printed Hybrid Electronic Assemblies With Embedded Components in Polymeric Substrates Subject to Extreme Acceleration Levels and Elevated Temperatures
Authors: Richards Hayden , Abusalma Hisham , Dasgupta Abhijit , Bujanda Andres , Tsang Harvey , Bowman Matthew
Published: November 2024

This study assessed the performance of printed hybrid electronic (PHE) assemblies subject to simultaneous exposure to elevated temperatures (up to 150 °C) and extreme mechanical shock (up to 100,000 g). The test specimens were rectangular beams measuring 3.2 mm thick, 12.7 mm wide, and 63.5 mm long, fabricated using injection molding from various polysulfone polymers. Several different electronic circuit elements — traces, passive components, and interconnects — were embedded into the largest flat surface of these substrates using a novel ‘mill-and-fill’ method. This method used conventional 5-axis CNC milling to generate pockets and channels into which the electrical elements were embedded. Traces were extrusion-printed with silver paste. The components used were 0-ohm resistors. Interconnects were formed using extrusion-printed tin-bismuth solder.

Testing was accomplished using an accelerated-freefall drop tower equipped with a shock amplifier and integrated furnace. Acceleration pulses (half-sine shape) ranged from 25,000 g to 100,000 g with pulse durations of ∼.03-.1 ms and velocity changes of 6–25 m/s. Elevated temperatures ranged from 88 °C to 150 °C in addition to room temperature (25 °C). The specimens were fixtured in a clamped-clamped configuration (largest flat face upright) and did not experience any secondary impact. Tests were instrumented with accelerometers, thermocouples / RTDs, and strain gauges with sampling grates of 1 MHz. Thermal cameras and high-speed optical cameras were also used. At the highest acceleration levels, peak strain values measured > 14,000 microstrain. Drop degradation assessment was based on changes in electrical performance metric (such as overall circuit resistance) or based on structural failure of circuit elements. Measurements were made either in real time during the drop event or intermittently after a select number of drops. Global and meso-scale modeling was conducted to validate measured strain response data, facilitate generation of a damage accumulation model, explain observed failure modes, and predict physical and electrical response for future geometries and applications.

Component separation and interconnect failure were the primary failure modes observed. As expected, number of cycles to failure decreased with increasing acceleration level and increasing temperature. The polysulfone beams themselves survived at all tested temperatures and most acceleration levels except for 100,000 g. Optical microscopy observations throughout testing showed cracking present in sintered silver traces, but this was not the sole predictor of circuit failure. Additional work is ongoing to further explore the causes for these failure modes and understand the implications of the physical response on different embedded components and specimen geometries.
Experimental Investigation of Single-Phase Forced Convection Heat Transfer With Water in Compressed Copper Foam
Authors: Alade Bolape , Kisitu Deogratius , Battleson May , Schaffarzick Denver , Ortega Alfonso
Published: November 2024

Open-cell metallic foams exhibit properties that make them suitable for enhancing the performance of heat sinks in advanced electronics cooling applications. Metallic foams have high surface area and low density, making them ideal for dissipating heat efficiently. However, while much research has focused on uncompressed metallic foams, particularly in single-phase cooling with air, there remains a gap in understanding their behavior in single-phase forced convection with liquid or in two-phase flow. Recent investigations have indicated that compressed copper foams can offer significant improvements in two-phase cooling efficiency at high heat fluxes when compressed in the direction of flow, but this advantage has not been explored in single-phase forced convection. This paper presents an experimental study aimed at evaluating the thermohydraulic performance of copper foam using deionized (DI) water as a coolant. The study focuses on investigating how foam compression influences heat transfer and fluid flow characteristics in single-phase forced convection. The experimental setup involves square copper foam samples of different heights, heated from below with flow entering parallel to the heated surface. The tested foam samples include a baseline uncompressed sample (compression ratio (CR) = 1) and two other compressed samples with CR = 2 and 4, corresponding to porosities of 92%, 81%, and 64%, respectively. Each sample has a footprint area of 25.4 mm × 25.4 mm and heights of 2.5, 3.5, and 5 mm. The experimental data demonstrate that foam compression significantly enhances the apparent heat transfer coefficient, attributed to increases in both effective thermal conductivity and apparent fin efficiency. This improvement in thermal performance is accompanied by an increase in pressure drop. The data trends are predicted well by a simple homogeneous, equilibrium flow model that predicts NuL α PeL1/2 but the data reveal an independent dependence on sample height.
Basic Study on Transient Flow Control Technique in Narrow Flow Passage With Flow Separation Region for Maximization of Cooling Performance of Heating Elements
Authors: Kobayashi Daiki , Fukue Takashi , Wakitani Shin
Published: November 2024

This study describes a method to maximize cooling performance in narrow passages with flow separation regions by applying pulsating flow. Forced convection cooling using pumps and fans is a standard cooling method for electronic devices. In most densely assembled and complicated passages, there are separation regions when cooling is performed by this method. However, in these regions, cooling is not sufficient. This prevents the accessible design of immersion cooling in computers and other devices. In this paper, pulsating flow is used to cool the heating element more effectively and more widely. In general, the cooling with pulsating flow results in uneven temperatures and areas that are not cooled. Therefore, it is necessary to repeatedly change parameters such as the frequency and time-averaged Reynolds number of the pulsating flow. This study applied an extremum seeking control approach to achieve maximum cooling even when the heat generation point changes. The following results were obtained from this study. The cooling target cooled better with pulsating flow than with steady flow. The pulsating frequency for the best cooling was found to be limited. The optimal pulsating frequency can be automatically guided to various cooling targets by controlling the pulsating frequency.
Scalable Large-Area Two-Phase Capillary-Enhanced Micro-Cooler Using Silicon Microchannel Fin Array With 3D Silicon Manifold for High-Heat-Flux Electronics Cooling Application
Authors: Kwon Heungdong , Kong Daeyoung , Lee Hyoungsoon , Palko James , Dede Ercan M. , Asheghi Mehdi , Goodson Kenneth E.
Published: November 2024

We have developed a silicon-based capillary-enhanced two-phase micro-cooler capable of removing a high heat flux > 200 Wcm−2 with water mass flow rate ≈ 28 g(min)−1 (vapor quality, xe ≈ 0.8) over a large area ≈ 2 cm × 2 cm at superheat < 20 °C, resulting in a thermal resistance of phase change, R″mean,2-ϕ ≈ 0.08 cm2°CW−1. By increasing the flow rate to ≈ 150 g(min)−1, a hybrid single/two phase regime prevails resulting in a critical heat flux ≈ 285 Wcm−2 (1.1 kW/chip) with minimal pressure drop ≈ 10 kPa, achieving 100× larger Coefficient of Performance (COP), compared to the conventional forced convective microchannel cooling. In this work, we utilize dense silicon channel fin array (height 100 μm, width 15 μm and 15 μm spacing) as capillary wicking structure in combination with a 3D silicon open-microchannel manifold (channel width and period ≈ 100 μm and 570 μm, respectively) for capillary-based liquid delivery and vapor extraction over large, heated area of 2 cm × 2 cm. The micro-cooler performs the best at low flow rates and high heat fluxes where the capillary flow and two-phase boiling dominates, resulting in a very uniform temperature distribution over the large area of the micro-cooler. At the high flow rates (pressurized flow), the coolant bursts out of the gap between the 3D manifold and the cold plate, resulting in single-phase cooling near the inlets of the micro-cooler. The temperature profile and its uniformity, or lack thereof, strongly depend on the competing effects of the single-phase and two-phase cooling regimes, which in turn depend on the flow rate and applied heat flux.
Passive Direct Liquid Cooling for High-Power Processors
Authors: Tyryshkin Alexei , Kim John , Amalfi Raffaele Luca , Enright Ryan
Published: November 2024

Refrigerant-based two-phase cooling systems are leading candidates for adoption in high-power electronics thermal management due to their potential for enhanced thermofluidic characteristics relative to single-phase liquid cooling. Passive cooling, leveraging gravity and fluid-vapor density difference instead of mechanical pumps to drive the flow, have attracted particular attention by offering further benefits, including lower maintenance requirements and higher operational reliability. However, the industrial implementation of passive cooling, tuned to specific application requirements, is a non-trivial task due to the complex two-phase flow physics and intricate thermo-hydraulic coupling during the evaporation and condensation processes. Designing a passive two-phase cooling system is a complex task requiring rigorous optimization of each individual component in the loop to ensure stable cooling performance in the desired range of heat dissipation and temperature. This challenge is further compounded by the dimensional constraints imposed by the electronic equipment. Thus, accurate experimental data and computational support are of crucial importance to realize the optimal design of such cooling loops.
Computational Fluid Dynamics (CFD) Modeling and Optimization of Large-Scale (3 cm X 3 cm) Silicon-Based Embedded Microchannels With 3D Manifold Micro-Coolers
Authors: Kong Daeyoung , Kwon Heungdong , Lee Haeun , Lee Hyoungsoon , Asheghi Mehdi , Goodson Kenneth E.
Published: November 2024

The continuing increase in CPU and GPU performances can be attributed mostly to the rise in frequency, scaling of chip area (bigger dies), advancements in thermal management, and improvements in thermal design power, among other factors. Over the past two decades, the size of a typical GPU die has increased from 100 mm2 to ∼800 mm2 in the year 2020. Silicon-based single-phase embedded microchannels with a large area of 30 mmx30 mm, featuring three-dimensional (3D) manifold (MF) μ-coolers, can potentially remove heat and minimize pressure drop. However, previous computational fluid dynamics (CFD) simulation findings indicated considerable temperature nonuniformity resulting in increased thermal resistance and maximum temperature. The primary cause of temperature non-uniformity is the abrupt flow acceleration at the entrance and sudden deceleration at the end section of the 3D-manifold inlet channels. This leads to a significant temperature rise in the middle region of the microcooler. In this study, we introduce innovative microcooler designs and conduct extensive computational fluid dynamics (CFD) simulations to achieve low thermal resistance, low-pressure drop, and crucially, uniform temperature distribution across the entire surface area of the microprocessor. To deal with this issue, our initial approach involved integrating converging inlet and diverging outlet channels into the 3D manifold. Although this method effectively dealt with the nonuniformity throughout the u-cooler’s area, it still resulted in a large pressure drop. Consequently, we implemented a narrow opening at the end of the inlet channels in the 3D manifold. This allows a portion of the coolant (50–80%) to bypass the microchannels in the cold plate to the exit plenum. As a result, the pressure was reduced by ∼66% compared to the conventional 3D manifold microchannel cooler.
Advanced Thermal Aware Mobile SoC Floorplan Design Optimization by Integrating Proactive Design Rule Check Process and Evolutionary Algorithms
Authors: Lee Myunghoon , Arimpoor Pallan Ouseph Lindo , Yaddanapudi Vamsi Krishna
Published: November 2024

The increasing demands for advanced functionality and high performance in modern mobile devices continuously escalate power consumption in system-on-chips (SoCs), intensifying thermally induced challenges, the floorplan design of application processors (AP) from the initial design stage must optimize the placement of each Intellectual Property (IP) block through thermal aware design, minimizing IP Block area, timing delays, maximum die temperature, and hotspot areas. This paper proposes an optimal IP Block placement workflow that satisfies key design parameters such as Performance, Power, and Area (PPA), using Computational Fluid Dynamics (CFD) thermal analysis and evolutionary algorithms. Additionally, to validate the utility of the developed workflow, a comparison of Dynamic Thermal Management (DTM) performance between base line and optimized candidate design under specific operating scenario is conducted, confirming the effectiveness of the workflow.
Enhanced Passive Cooling in Thermal Interface Materials via Encapsulated Phase Change Material Additives
Authors: Kasitz Joshua , Ghufran Muhammad , Huitink David
Published: November 2024

Phase change materials (PCMs) offer significant upside in passive cooling potential, allowing them to be integrated in electronics as thermal buffers to prevent damaging localized heating effects. This impact can greatly improve the reliability of electronic packages and reduce the opportunity for thermal stress induced failures. Integrating passive cooling into electronics is difficult, especially in the case of PCMs, as additional packaging architectures are needed to facilitate PCM incorporation that often negatively affects the module’s power density. Encapsulated phase change materials (ePCMs) achieve a stable PCM system by creating spherical particles with a PCM core and a protective shell material. The shell contains the PCM through both solid and liquid phase, removing concerns of handling liquid PCM within an electronic stack. The particles contain most of the thermal energy storage capability of the PCM and are mechanically more reliable than the bulk system. These particles can be introduced into existing materials to form ePCM composites. Balancing the functionality of both material types is important for upgrading current materials in electronic packaging. Thermal interface materials (TIMs) are at the forefront of electronic packaging research as these are a significant bottleneck in the thermal management of electronics. This study introduces ePCMs into TIMs to create a more thermally capable interface material. These new composites will look to take advantage of ePCM fillers to provide passive cooling across the interface and be used as thermal conductivity fillers. In this study, ePCM particles with a paraffin core and a titania shell will be combined with three different TIMs of varying thermal conductivity and viscosity. The composites will be thermally and mechanically evaluated.
Thermal Performance of Common Cold Plate for Pumped Single- and Two-Phase Direct Liquid Cooling for Next Generation High Power Server Processors
Authors: Kulkarni Devdatta , Gulick John , King Jeff , Jarrett Brian , George Paul , Feldman Yoav
Published: November 2024

The rapid expansion of Generative AI and ML applications has led to a surge in demand for advanced accelerators. These next-generation accelerators require high power, with some reaching nearly 1kW and continuing to rise. Consequently, server power envelopes have expanded to 10kW and beyond, while rack-level power for AI applications is approaching 100kW. The high TDP (Thermal Design Power) and heat flux of these processors, combined with power-dense servers and racks, necessitate cooling technologies with superior thermal performance. As IT power consumption escalates, most data centers are transitioning to liquid cooling solutions that align with corporate sustainability objectives. This paper assesses the thermal performance of single and two-phase pumped direct liquid cooling technologies. It explores a unified cold plate construction approach, a COMMON cold plate, enabling both technologies to address cooling challenges faced by data center operators and to expedite the Time to Market (TTM) for server manufacturers’ cooling solutions. The paper outlines the design methodology, laboratory testing procedures, and thermal performance of a common cold plate design suitable for both single and two-phase pumped direct liquid cooling technologies. For single-phase liquid cooling, Propylene Glycol-25 (PG25) is the chosen fluid medium, while a medium-pressure refrigerant with a lower Global Warming Potential (GWP) is considered for two-phase cooling. Three types of Thermal Test Vehicles (TTVs) were utilized under uniform and non-uniform heat load conditions, with power levels up to and beyond 1kW and high heat fluxes up to 300W/cm∧2. Additionally this paper emphasizes the significance of characterizing non-uniform heat flux in thermal solutions by varying the heat flux at high heat flux locations. Understanding how to cool these high heat flux hotspots are crucial for the development of thermal solutions, as the heat fluxes of new generation accelerators are significantly higher than those of traditional processors. In conclusion, the paper highlights the need for further ecosystem development for various cooling loop components to enhance the adoption of two-phase liquid cooling solutions.
Additively Manufactured Cold Plate Integrated With Evaporator Wicks and Phase Separators for Thermal Management of Multiple High-Heat-Flux Heat Sources
Authors: Shaeri Mohammad Reza , Demydovych Maksym , Chen Chien-Hua
Published: November 2024

In this study, a Hybrid Two-Phase Cooling System (HTPCS) was developed, combining the advantages of capillary-driven evaporation from wick structures with pumped two-phase cooling. The cold plate, the core element of the HTPCS, was made of AlSi10Mg and incorporated seven heaters distributed in a non-patterned configuration across its surface. Each heater was assigned a wick structure as an evaporator. The key contribution of this study lies in (i) fabricating the entire cold plate through one single additive manufacturing (AM) process, and (ii) preventing the flooding of individual evaporators using an internal phase separator. The first merit results in a substantial reduction in fabrication complexity compared to traditional manufacturing processes, representing a crucial milestone in the path toward commercializing the developed HTPCS in this study. The second merit results in a further reduction in the thermal resistance of the cold plate. The HTPCS exhibited significant thermal performance, operating at heat fluxes exceeding 505 W/cm2 and achieving low and uniform thermal resistances of ∼0.16 K-cm2/W. Furthermore, the HTPCS operated within a low pumping power range, below 0.14 W. This study introduces a promising cooling technology for the thermal management of the next generation of miniaturized electronic devices, especially those integrating multiple high-heat-flux heat sources.
Study on the Impact of Prolonged High-Temperature Exposure on the Reliability of Lead-Free Solder Joint Assemblies Under Vibration
Authors: Lall Pradeep , Mehta Vishal , Suhling Jeff , Blecker Ken
Published: November 2024

The solder joint stands out as one of the most vulnerable elements in electronic components and assemblies. In automotive systems, including engine control units, variable valve sensors, and crankshaft-camshaft sensors, many electronic assemblies are located under the hood. These components are frequently exposed to elevated temperatures reaching up to +150°C. Moreover, they undergo drop-impact incidents, experience vibrations, and encounter shocks. In this demanding environment, electronic devices may also be subjected to strain rates ranging from 1 to 100 times per second. To enhance the durability of electronic packages in high-temperature and high-strain-rate conditions, it is imperative to focus on the mechanical properties and statistics of lead-free solder alloys. The combination of vibrations and elevated temperatures has the potential to accelerate the degradation of electronic components. Existing research on solder joints has primarily concentrated on either vibrational stresses in room temperature environments or thermal cycling, particularly for traditional and unaged solders such as SAC105 and SAC305. Previous studies involving Finite Element (FE) analysis have exclusively considered the linear-elastic behavior of solder materials. SAC-Q solder was employed in the assembly of the CABGA208 Package-PCB assemblies. Unaged and isothermally aged PCB-Package assemblies were tested for failure at different ambient test temperatures up to 150°C, with vibration loads of 5g and 10g applied. To model harmonic vibration loading on PCB-Package assemblies under various situations, finite element (FE) analysis was carried out. The first natural frequencies of test boards featuring CABGA208 packages were measured at different test temperatures (e.g., 25°C, 75°C, and 150°C) and vibration g-levels using a combination of experimental and Finite Element Analysis (FEA) based modal analysis. The number of cycles to failure was measured and compared across various test conditions (unaged and aged) through Weibull plots. Peak displacements under vibrations at different g-levels were measured and compared for the test vehicle using the 2D-DIC method. Hysteresis stress-strain curves and accumulated plastic work densities were extracted through FE analysis, and comparisons were made for various g-levels and ambient temperatures. Damage relationship model is established for life prediction of the PCB-Package assembly.
Thermal Cycling Reliability on Encapsulated Flexible Printed Circuit Fabricated With Water-Based Ink and Room-Temperature Curable Adhesive
Authors: Lall Pradeep , Bimali Sabina , Miller Scott
Published: November 2024

The application of room-temperature curable adhesive and water-based ink offers an economical and sustainable method in the field of electronics production. On the other hand, little is known about how encapsulation and thermal cycling affect the functionality of circuits fabricated using these materials. The purpose of this study is to look into how thermal cycling circumstances and encapsulation techniques affect the reliability and performance of circuits made with room-temperature curable adhesive and water-based ink. Understandings from this research will fill this knowledge gap and improve the processes involved in the design and production of environmentally friendly electronic circuits, leading to the development of sustainable electronics technology. Even with the progress made in electronics production, not much is known about how encapsulation will affect the thermal cycling reliability of a circuit made with water-based ink and room-temperature curable adhesive. Comprehensive studies addressing the performance and reliability test of circuits made using this environmentally friendly method are lacking in the current literature. This lack of systematic studies that examine these circuits’ behavior in different environmental settings — like thermal cycling with encapsulation procedures — is the limitation. As a result, the lack of knowledge makes it difficult to optimize manufacturing procedures and compromises the production of robust, reliable electronics made of eco-friendly materials. It is crucial to address this shortcoming to further sustainable electronics technology and encourage the electronics industry to embrace environmentally friendly manufacturing practices. This paper investigates the effect of encapsulation in flexible printed circuits fabricated with water-based inks and room-temperature curable adhesives, undergoing thermal cycling processes. A comparison will be made between the encapsulated and non-encapsulated circuits manufactured with room-temperature processable interconnects, coupled with water-based inks, for both test designs: individual components test and functional circuit test. The study includes the realization of a differentiator circuit through aerosol jet printing, employing room temperature interconnects for component attachment, and comparing the performance of encapsulated circuits with that of the non-encapsulated circuit, under Thermal Cycling.
State of Health Estimation Model Development for Li-Ion Battery Lifetime Considering Calendar Aging and Post-Knee Degradation
Authors: Lall Pradeep , Soni Ved , Bimali Sabina
Published: November 2024

Lithium-ion batteries are the most popular choice for power sources in the modern consumer electronics products, due to their exceptional specific energy, specific capacity, and other features including long cycle life, high columbic efficiency, and low self-discharge rate. To address the modern and ubiquitous concerns of improving product sustainability and counter supply-chain shortages, understanding battery degradation is pivotal for extending battery life, improving battery materials, and informing end user about device battery health to prompt replacement as needed. Battery health degradation as a phenomenon starts even before the battery is put into use in a device, as the battery capacity degrades during storage (calendar aging); and continues even after its cycling life is completed, wherein the battery experiences catastrophic failure as its health degrades rapidly (knee-point failure). The majority of the models available in literature today focus mainly of estimating battery health during its usage phase. However, it is critical to model battery health in the pre-use phase, to understand the battery health status when its put into use, and even after the battery has experienced knee-point failure to inform the user of the need for urgent replacement. This study proposes a cell lifetime degradation model which addresses all the three aforementioned phases of battery life: calendar aging, cycle aging, and post-knee aging. By testing batteries using different case-specific parameters, battery degradation data has been acquired for different aging stages. This data is then used to build individual models for the three stages which have later been combined to form the cell lifetime degradation model. Moreover, the study provides markers to estimate onset of knee-point failure using battery parameters that can be made accessible to the end user.
Sequential High Humidity and Isothermal Evolution of UF-Substrate Interface
Authors: Lall Pradeep , Choudhury Padmanava , Pandurangan Aathi
Published: November 2024

FCBGA architecture has become increasingly complex, with increases their power requirements, and in conjunction, these packages are ubiquitous modern-day automotive platforms. The assurance of the reliability of the packages requires a fundamental understanding of the damage accrual at the interfaces. Underfills are used to provide supplemental support to the interconnects between the chip and substrate. Long-term high humidity and high temperature are detrimental environmental stresses which may increase the propensity for the premature failure of the interface followed by interconnect failures. In this study, the objective is to analyze the interface strength reliability between underfill/substrate due to sequential high-temperature and high humidity operation.
Socialising the Frequency Code: Effects of gender and age on iconic associations of pitch
Authors: Calhoun Sasha , Warren Paul , Mills Joy , Agnew Jemima
Published: November 2024

Burgeoning research has shown the pervasiveness of sound symbolism, a type of iconicity, in language. However, little work looks at how individual experiences and beliefs affect sound symbolic associations. We investigate pitch associations under the Frequency Code, which links high vs low pitch to small vs large body size and female vs male gender (via sexual dimorphism), long claimed to underlie “universal” meanings like submissiveness vs dominance. While such associations appear widespread, the Frequency Code assumes ideological links, e.g., between dominance and masculinity, which differ between individuals and cultures. In Implicit Association Task experiments with English-speaking listeners, we show high pitch is implicitly associated with small size and female gender, and low with large and male, following the Frequency Code. Crucially, though, the strength of these associations varies by social factors. Associations are stronger for male voices and listeners, particularly older men, as ideologies related to the Frequency Code (linking large size, strength, and dominance) tend to be stronger for men. The association of pitch with gender is stronger than with body size, reflecting stronger gender-based stereotypes. This work shows that social experience shapes and reinforces iconic associations, with important implications for how iconic meanings develop and are processed.
Forecast skill assessment of an operational continental heat-cold-health forecasting system: New avenues for health early warning systems
Authors: Quijal-Zamorano Marcos , Petrova Desislava , Martínez-Solanas Èrica , Herrmann François R. , Rodó Xavier , Robine Jean-Marie , Marí-Dell’Olmo Marc , Achebak Hicham , Ballester Joan
Published: November 2024

More than 110,000 Europeans died as a result of the record-breaking temperatures of 2022 and 2023. A new generation of impact-based early warning systems, using epidemiological models to transform weather forecasts into health forecasts for targeted population subgroups, is an essential adaptation strategy to increase resilience against climate change. Here, we assessed the skill of an operational continental heat-cold-health forecasting system. We used state-of-the-art temperature-lag-mortality epidemiological models to transform bias-corrected ensemble weather forecasts into daily temperature-related mortality forecasts. We found that temperature forecasts can be used to issue skillful forecasts of temperature-related mortality. However, the forecast skill varied by season and location, and it was different for temperature and temperature-related mortality due to the use of epidemiological models. Overall, our study demonstrates and quantifies the forecast skill horizon of heat-cold-health forecasting systems, which is a necessary step toward generating trust among public health authorities and end users.
Fractional change of scattering and absorbing aerosols contributes to Northern Hemisphere Hadley circulation expansion
Authors: Ying Tong , Li Jing , Fu Qiang , Liu Guanyu , Zhang Lu , Xia Yan , Hu Yongyun
Published: November 2024

The relative amount of scattering and absorbing aerosols is essential in determining the aerosol radiative and climate effects. Using reanalysis datasets and climate simulations, here, we show that changes in the relative amount of scattering and absorbing aerosols in the Northern Hemisphere (NH) high latitudes, manifested as long-term decreasing trends in aerosol single-scattering albedo (SSA), have played an important role in driving the widening and weakening trends of the NH Hadley circulation (HC) since the early 1980s. Decreasing SSA in the NH middle and high latitudes can notably warm the troposphere there, thus reducing the equator-to-pole temperature gradient, increasing static stability in mid-latitude regions, and leading to the widening and weakening trends of NH HC. Further analysis of the Coupled Model Intercomparison Project Phase 6 (CMIP6) aerosol forcing–only simulations also supports the importance of SSA trends in perturbing NH HC through the above mechanism.
INF2 mutations cause kidney disease through a gain-of-function mechanism
Authors: Subramanian Balajikarthick , Williams Sarah , Karp Sophie , Hennino Marie-Flore , Jacas Sonako , Lee Miriam , Riella Cristian V. , Alper Seth L. , Higgs Henry N. , Pollak Martin R.
Published: November 2024

Heterozygosity for inverted formin-2 (INF2) mutations causes focal segmental glomerulosclerosis (FSGS) with or without Charcot-Marie-Tooth disease. A key question is whether the disease is caused by gain-of-function effects on INF2 or loss of function (haploinsufficiency). Despite established roles in multiple cellular processes, neither INF2 knockout mice nor mice with a disease-associated point mutation display an evident kidney or neurologic phenotype. Here, we compared responses to puromycin aminonucleoside (PAN)–induced kidney injury between INF2 R218Q and INF2 knockout mice. R218Q INF2 mice are susceptible to glomerular disease, in contrast to INF2 knockout mice. Colocalization, coimmunoprecipitation analyses, and cellular actin measurements showed that INF2 R218Q confers a gain-of-function effect on the actin cytoskeleton. RNA expression analysis showed that adhesion and mitochondria-related pathways were enriched in the PAN-treated R218Q mice. Both podocytes from INF2 R218Q mice and human kidney organoids with an INF2 mutation (S186P) recapitulate adhesion and mitochondrial phenotypes. Thus, gain-of-function mechanisms drive INF2-related FSGS and explain this disease’s autosomal dominant inheritance.
Acoustofluidic tweezers via ring resonance
Authors: Xu Xianchen , Jin Ke , Yang Kaichun , Zhong Ruoyu , Liu Mingyuan , Collyer Wesley , Jain Shivam , Chen Ying , Xia Jianping , Li Junfei , Yang Shujie , Dowell Earl H. , Huang Tony Jun
Published: November 2024

Ring resonator (RR) devices are closed-loop waveguides where waves circulate only at the resonant frequencies. They have been used in sensor technology and optical tweezers, but controlling micron-scale particles with optical RR tweezers is challenging due to insufficient force, short working distances, and photodamage. To overcome these obstacles, an acoustofluidic RR-based tweezing method is developed to manipulate micro-sized particles that can enhance particle trapping through the resonance interaction of acoustic waves with high
Q
factor (>3000), more than 20 times greater than traditional acoustic transducers. Particles can be precisely manipulated within the RR by adjusting the signal phase, with trapping amplified by enlarging the connected waveguide. Rapid particle mixing is achieved when particles are placed between the waveguide and RR. The signal path is strengthened by strategically positioning the RR in a two-dimensional plane. Acoustofluidic RR tweezers have immense potential for advancing applications in biosensing, mechanobiology, lab-on-a-chip, and cell-cell communication research.
Frequent genetic exchanges revealed by a pan-mitogenome graph of a fungal plant pathogen
Authors: van Westerhoven Anouk C. , Dijkstra Jelmer , Aznar Palop Jose L. , Wissink Kyran , Bell Jasper , Kema Gert H. J. , Seidl Michael F.
Published: November 2024

Mitochondria are present in almost all eukaryotic lineages. The mitochondrial genomes (mitogenomes) evolve separately from nuclear genomes, and they can therefore provide relevant insights into the evolution of their host species.
Fusarium oxysporum
is a major fungal plant pathogen that is assumed to reproduce clonally. However, horizontal chromosome transfer between strains can occur through heterokaryon formation, and recently, signs of sexual recombination have been observed. Similarly, signs of recombination in
F. oxysporum
mitogenomes challenged the prevailing assumption of clonal reproduction in this species. Here, we construct, to our knowledge, the first fungal pan-mitogenome graph of nearly 500
F
.
oxysporum
mitogenome assemblies to uncover the variation and evolution. In general, the gene order of fungal mitogenomes is not well conserved, yet the mitogenome of
F. oxysporum
and related species are highly colinear. We observed two strikingly contrasting regions in the
F. oxysporum
pan-mitogenome, comprising a highly conserved core mitogenome and a long variable region (6–16 kb in size), of which we identified three distinct types. The pan-mitogenome graph reveals that only five intron insertions occurred in the core mitogenome and that the long variable regions drive the difference between mitogenomes. Moreover, we observed that their evolution is neither concurrent with the core mitogenome nor with the nuclear genome. Our large-scale analysis of long variable regions uncovers frequent recombination between mitogenomes, even between strains that belong to different taxonomic clades. This challenges the common assumption of incompatibility between genetically diverse
F. oxysporum
strains and provides new insights into the evolution of this fungal species.

IMPORTANCE

Insights into plant pathogen evolution is essential for the understanding and management of disease.
Fusarium oxysporum
is a major fungal pathogen that can infect many economically important crops. Pathogenicity can be transferred between strains by the horizontal transfer of pathogenicity chromosomes. The fungus has been thought to evolve clonally, yet recent evidence suggests active sexual recombination between related isolates, which could at least partially explain the horizontal transfer of pathogenicity chromosomes. By constructing a pan-genome graph of nearly 500 mitochondrial genomes, we describe the genetic variation of mitochondria in unprecedented detail and demonstrate frequent mitochondrial recombination. Importantly, recombination can occur between genetically diverse isolates from distinct taxonomic clades and thus can shed light on genetic exchange between fungal strains.