bluuebunny/crossref_metadata_2025_split huggingface dataset:
Machine Learning Enables Autonomous Vehicles Under Extreme Environmental Conditions
Authors: Quach Nhi V. , Park Jewoo , Kim Yonghwi , Cheng Ruey-Hwa , Jenco Michal , Lee Alex K. , Yin Chenxi , Won Yoonjin 
Published: December 2022

Abstract
Autonomous vehicles are part of an expanding industry that encompasses various interdisciplinary fields including but not limited to dynamics and control, thermal engineering, sensors, data processing, and artificial intelligence. Autonomous vehicles require the use of various sensors, such as optical cameras, RADAR (radio detection and ranging), or LiDAR (light detection and ranging), to navigate on the road with the aim of self-driving. However, the exposures to environmental conditions related to the combination of surrounding temperature and humidity lead to challenges in sensor performance. For example, the sensor’s temperature will increase as the heat is generated during the vehicle’s usage. On the other hand, the sensor system will undergo thermal shock from the temperature difference the due to sudden changes in temperature, such as moving from an indoor garage at room temperature to −10°C environments. Furthermore, the consistent exposure to the cold weather may occur frosting, which can obstruct the optical sensor’s visibility. Those issues limit the potential of data processing from optical cameras and consequence autonomous driving reliability at extreme environmental conditions.
To review the requirements for sensor performance used in autonomous vehicles and to formulate solutions addressing potential concerns to improve autonomous driving safety, we simulate camera operating conditions in the real world. First, we correlate the common placements of optical sensors, mainly focusing on cameras, in autonomous vehicles to naturally occurring environmental conditions in relation to temperature and humidity. With this correlation, we aim to provide an understanding of potential areas on the vehicle that may be more prone to environmental factors of thermal shock or humidity variations. Second, we examine the condensation and frosting mechanism and formation sequence on the vehicle surfaces (e.g., windshield and camera lenses), which is then used to determine the level of water on the lenses before the sensor vision is impeded. Third, we introduce and conceptualize machine learning models that can extract features by employing object detection algorithms that perform image restoration to reconstruct areas with deterioration despite the presence of the droplets or frosts on the camera. With this research, we aim to provide a better understanding of the potential caveats and algorithm solutions that can help the capability for autonomous driving even under extreme environmental conditions.
Comparative Analysis of Direct and Indirect Cooling of Wide-Bandgap Power Modules and Performance Enhancement of Jet Impingement-Based Direct Substrate Cooling
Authors: Barua Himel , Gurpinar Emre , Xue Lingxiao , Ozpineci Burak 
Published: December 2022

Abstract
With the development of high-power and high-torque machines, requirements for high-power density electronics are increasing. Thermal management of such systems requires high heat extraction. Conventional air cooling based heat sinks and cold plate based liquid cooling have their own benefits for various applications but has limitations for high power density applications. The current study explores a jet impingement based direct substrate cooling system that was implemented for a SiC based direct bonded Cu substrate for various power losses. Numerical comparison between jet impingement cooling and conventional horizontal/indirect cooling (pin fin heat sink and genetic algorithm-optimized heat sink) showed that the area weighted average of the heat transfer coefficient (HTC) is high for both horizontal cooling designs, and the local HTC is higher for jet impingement. Design iterations were undertaken to resolve the bottleneck of this cooling system. Increasing the number of nozzles helped to cover more area at the direct bonded Cu bottom plate, which drops the chip temperature considerably. With a constant flow rate, increasing the number of nozzles would decrease local jet velocity, which reduces the heat extraction by jet impingement. This issue can be addressed by reducing the diameter of nozzle but doing so results in a high pressure drop where the design constraint is 2 psi. A flared nozzle design is proposed, which has a higher spreading angle of the jet that increases the flow coverage and reduces the pressure drop of the coolant loop.
AI/ML Applications for Thermally Aware SoC Designs
Authors: Norman Adam , Gallina Mark , Zhu Olena , Weiner Joyce , Garita Gonzalez Fabian 
Published: December 2022

Abstract
Thermal considerations are a critical facet in SoC and System design. There are numerous difficulties in performing comprehensive thermal analysis on modern SoC designs as well as considerable difficulty in moving towards a cross-discipline co-design strategy. The design space is large and growing more complex with each generation, coupled with long evaluation/simulation time for sufficiently accurate thermal response. Thermal feedback into design iterations were additionally slowed by the huge numbers of excitation (workloads) scenarios needed to provide design robustness. Augmented Intelligence and machine learning (ML) approaches are explored to address some of these difficulties, as well as development of a fast evaluation function to reduce total computation time. Various clustering and modeling techniques are used to improve stimulus/workload selection and coverage for analysis, which further reduces evaluation time. This huge enhancement in evaluation time has opened new opportunities for co-design work, ML optimization schemes are applied to address the high degrees of freedom present at the SoC level. The results have been impressive, showing huge potential for thermal improvements which translate directly into improved product performance.
Drop Durability of Printed Hybrid Electronic (PHE) Assemblies Under Extreme Acceleration Level
Authors: Abusalma Hisham , Dasgupta Abhijit , Bujanda Andres , Yu Jian , Tsang Harvey 
Published: December 2022

Abstract
In this paper, the drop durability of printed hybrid electronic (PHE) assemblies of various form factors is studied under extreme drop conditions with accelerations up to 20,000 G. Test specimens considered here include: circular disk, cantilever beam, and hemispherical dome samples.
The disk is made from a UV hardened resin material and mounted using a 3-point fixture. This specimen experienced overstress fracture at 20,000 G drops. Additionally, it was very susceptible to repetitive drop failure. The failure site was at the expected site of maximum flexure, as revealed by finite element modeling and by high-speed video recording.
The cantilever beam is a standard 1.6 mm thick FR4 substrate with printed silver traces. The substrate was durable but suffered from high strains near the clamp which are expected to cause damage to the silver conductive traces printed on them. The beam specimen was instrumented with strain gages and was also subjected to high-speed video recording of the drop event. The beam was found to vibrate in its first two bending modes when dropped at 10,000 G.
The hemispherical substrates for the dome specimens were made from several different polymeric materials and were mounted in a threaded fixture. Drop durability varied with choice of substrate material and fabrication method. Some showed catastrophic failures after 1–5 drops at 20,000 Gs while some survived more than 50 drops at 20,000 G. The failure site for all failed dome specimens was at the threads used for mounting to the fixture.
Liquid to Air Cooling for High Heat Density Liquid Cooled Data Centers
Authors: Heydari Ali , Radmard Vahideh , Eslami Bahareh , Tradat Mohammad I. , Manaserh Yaman , Miyamura Harold , Chowdhury Uschas , Shahi Pardeep , Hall Kevin Dave , Sammakia Bahgat , Rodriguez Jeremy 
Published: December 2022

Abstract
Growing demand for dense and high-performing IT compute capacity to support deep learning and artificial intelligence workloads necessitates data centers to look for more robust thermal management strategies. Today, data centers across the world are turning to liquid-based cooling solutions to keep up with the increased cooling demand for high power racks approaching 100kW of heat dissipation. Deploying direct-to-chip cold plate liquid cooling is one of the mainstream approaches which allows targeted cooling of high-power processors. This study provides the framework for a hybrid in row cooler (IRC) with liquid-to-air (L2A) heat exchanger (HX) system delivering chilled coolant to liquid-cooling cold plates mounted to the high heat dissipation electronics. This approach is useful for high heat density cooling of racks where no primary facility coolant is available at the data center. The present study aims to investigate the thermo-hydraulic performance of a distinct L2A IRC system that supplies cold secondary coolant (PG 25%) into the cooling loops of liquid-cooled servers in racks within an existing air-cooled data center. Thermal test vehicles (TTVs) are built to replicate actual high heat density servers. From the cold plate to data center level the proper choice of each level component was described based on their cooling performance and relevance. Three different cooling loop/rack designs are characterized experimentally, and detailed analytical and numerical (FNM) simulations are developed to analyze the heat exchanger performance. The FNM and CFD model of a data center are done in two steady and transient forms to study the performance of the L2A IRC in a data center.
Melt Front Enhancement of Phase Change Materials via Nanoparticle Inclusion for Improved Heat Transfer and Cyclability
Authors: Kasitz Joshua , Marshall Larry , Huitink David 
Published: December 2022

Abstract
Passive cooling techniques are widely sought-after solutions to thermal management issues in high power electronics due to increased energy dissipation in reduced areas. Phase change materials (PCMs) present a promising secondary passive thermal management opportunity by absorbing a large amount of energy as an isothermal process. This phenomenon can be utilized in various ways as a thermal management tool; including temperature spike alleviation, energy storage, and secondary passive cooling. Though PCMs have promising passive cooling ability, often it is difficult to select an appropriate or effective PCM for the specific application due to deficiencies in a particular material property. Previous studies have demonstrated the ability to alter PCM properties through the homogeneous inclusion of nanoparticles. Thermal conductivity is a particularly important metric for enhancement via nanoparticles due to the typically low conductivity of PCMs with high latent heats. Previous studies demonstrate the successful augmentation of this property. A large limiting factor to enhanced PCM passive cooling is related to the propagation of the melt front, representing the region of large energy absorption. In many cases, the melt front moves too slowly to effectively transfer energy away from the device. Slow material response time can also be problematic in the re-solidification process, limiting cyclability. Work has been conducted to monitor the melt front response to a thermal load. Early in the melting process, conduction dominates the heat transfer mechanism. This paper will examine the impact of nanoparticle inclusion as a means of controlling the melt front propagation. Using nanoparticles to control the composite thermal conductivity should lead to optimization ability of PCM melt characteristics to align with thermal management needs.
CFD Simulation-Based Comparative Study of Forced Convection Single-Phase Liquid Immersion Cooling for a High-Powered Server
Authors: Murthy Prajwal , Gupta Gautam , Herring Joseph , Lamotte-Dawaghreh Jacob , Sivaraju Krishna Bhavana , Bansode Pratik , Modi Himanshu , Agonafer Dereje , Mynampati Poornima , Sweeney Mike 
Published: December 2022

Abstract
Due to increasing computational workload and thermal design power requirements of high power-density microelectronics, low heat carrying capacity and poor thermal conductivity of air renders air-cooling insufficient to meet the cooling demands of component heat generation in high-performance servers. A more effective method of removing heat from these high-powered components is by using single-phase immersion cooling with a dielectric fluid of superior thermal properties and high boiling point. This study compares traditional forced-air cooling with forced convection single-phase immersion cooling to minimize chip junction temperatures of a 776 W high powered data center server using CFD simulations. The server is of spread-core configuration consisting of 2 CPU heatsink assemblies and 32 DIMM units with their specified chip thermal design power (TDPs). The first method consists of forced-air cooling with a 28°C air inlet supply and 110 CFM inlet air flowrate to establish baseline thermal performance. The second method is forced convection single-phase immersion cooling of the server in EC-110 dielectric fluid at 28 °C temperature and 2 GPM flow rate to observe server performance improvement in CPU case temperatures, maximum DIMM temperature, and server pressure drop through immersion cooling method. Lastly, CFD simulations are performed at different fluid inlet temperatures of 30, 40 and 50 °C, and 2 GPM fluid inlet flow rate, and the percentage change in the CPU case temperatures, server pressure drop and the maximum DIMM temperatures with fluid inlet temperature were studied.
Impact of Immersion Cooling on Thermomechanical Properties of Non-Halogenated Substrate
Authors: Bhandari Rabin , Lakshminarayana Akshay Boovanahally , Sivaraju Krishna Bhavana , Bansode Pratik Vithoba , Kejela Ephrem , Agonafer Dereje 
Published: December 2022

Abstract
Detailed study of material compatibility of the various electronics packaging materials for immersion cooling is essential to understand their failure modes and reliability. The modulus and thermal expansion are critical material properties for electronics mechanical design. Substrate is a critical component of electronic package and heavily influences failure mechanism and reliability of electronics both at the package and board level. This study mainly focuses on two major challenges. The first part of the study focuses on the impact of thermal aging in dielectric fluid for single-phase immersion cooling on the non-halogenate substrate’s thermo-mechanical properties. The second part of the study is the impact of thermal aging on thermo-mechanical properties of substrate in the air. The non-halogenated low Coefficient of Thermal Expansion (CTE) bismaleimide triazine (BT) resin laminate is used for its ultra-low CTE which in turn reduce the warpage of substrate. Moreover, the substrate has high glass transition temperature and high stiffness suitable for the application which requires high heat resistance. The substrate is aged in ElectroCool EC100 dielectric fluid, and air for 720 hours at three different temperatures: 22°C, 50°C, and 75°C. The complex modulus is characterized before and after aging for both parts and compared.
Evolution of Propensity for Chip-UF FCBGA Interface Delamination Under Fatigue-Loading and Sustained High Automotive Temperatures
Authors: Lall Pradeep , Pandurangan Aathi Raja Ram , Williamson Jaimal 
Published: December 2022

Abstract
Underhood applications in automotive are increasingly using electronics systems for safety and critical functions. In flip-chip ball grid array (FCBGA) packages, underfill (UF) forms the integral mechanical support between the substrate and die. In addition, underfills protect the chip against shock, vibration, moisture, and radiation. Underfills provide great mechanical support to the solder interconnects and limit the amount of plastic work during temperature excursions. Delamination is of the significant failure modes observed at chip-UF interfaces. Chip-UF interfaces have not been studied widely under cyclic fatigue loading with sustained high-temperature exposure. Chip-UF bi-material samples are prepared and subjected to long-term high-temperature aging at 100°C and then tested under four-point bend fatigue loading. The specimens have been exposed to isothermal aging for 30 days, 60 days, 90 days, 120 days, and 180 days. The interfacial crack growth rate with respect to the number of fatigue cycles has been determined from the experiment. The steady-state energy release rate and range of mode-I stress intensity values (ΔKI) have been computed for each of the test conditions. Paris power law has been used to establish the relationship between the crack growth rate and the range of stress intensity factors. Paris exponents (A,n) are determined from the relationship to understand the evolution in interfacial fracture toughness with respect number of days of aging under fatigue loading.
Experimental Study of Transient Hydraulic Characteristics for Liquid Cooled Data Center Deployment
Authors: Heydari Ali , Shahi Pardeep , Radmard Vahideh , Eslami Bahareh , Chowdhury Uschas , Sivakumar Akiilessh , Lakshminarayana Akshay , Miyamura Harold , Gupta Gautam , Agonafer Dereje , Rodriguez Jeremy 
Published: December 2022

Abstract
Increasing demands for cloud-based computing and storage, Internet-of-Things, and machine learning-based applications have necessitated the utilization of more efficient cooling technologies. Direct-to-chip liquid cooling using cold plates has proven to be one of the most efficient methods to dissipate the high heat fluxes of modern high-power CPUs and GPUs. While the published literature has well-documented research on the thermal aspects of direct liquid cooling, a detailed account of transient hydraulic investigation is still missing. In this experiment, a total of four 52U racks with four high-power TTV-servers (Thermal Test Vehicles) in each rack were designed and deployed. Each server consists of eight GPU TTVs and six NV switch heaters. Each of the two racks has a different vendor rack manifold and cooling loop modules (CLM). A 450 kW coolant distribution unit (CDU) is used to supply 25% propylene glycol coolant to these racks. Each rack has its own rack-level flow control valve to maintain the same flow rate. The present study provides an in-depth analysis of hydraulic transients when rack-level flow control valves are used with and without flow control. The operating conditions of the CDU are varied for different parameters, such as a constant flow rate, constant differential pressure, and constant pump speed. Furthermore, hydraulic transient is examined when the cooling loop modules are decommissioned from the rack one by one. The effect of this step-by-step decommissioning is assessed on the CDU operation and other racks. The pressure drop-based control strategy has been developed to maintain the same flow rate in the remaining servers in the rack when some cooling loop modules are decommissioned.
Deep Learning for Prediction of Print Parameters and Realized Electrical Performance and Geometry on Inkjet Platform
Authors: Lall Pradeep , Kulkarni Shriram , Soni Ved , Goyal Kartik , Miller Scott 
Published: December 2022

Abstract
A closed-loop deep learning approach for correlating the print parameters with realized electrical performance and geometry estimations on an inkjet platform has been presented in this paper. An estimate of the changes in the print parameters and the recognized print dimension is necessary to print reliable and fine conductive traces. The inks used for this analysis are both particle and particle-free silver inks, and the comparison of the same is also studied. A closed-loop control algorithm is used to attain the desired electrical and geometrical values by changing the print parameters without any user intervention. Sensing is achieved by an automatic print parameter sensing system using a camera that captures the print to identify the geometry and dimension of the same. Once the realized print parameters are determined, a deep learning neural network regression model based on these parameters is used to predict the desired input print parameters, which are used to achieve the desired geometry and dimension of the print. These new parameter values are passed on to the printing software to optimize the print and attain the desired geometry and characteristics.
Additively Printed Flexible Charging Circuits and Effect on Evolution of Line Resistance and Charging Current in Charging Thin Flexible Batteries
Authors: Lall Pradeep , Soni Ved , Miller Scott 
Published: December 2022

Abstract
Flexible electronics are increasingly finding commercial applications ranging from wearable activity tracking watches, rollable displays, foldable smartphones, and biometrics. There is an acceleration of effort in the research and development of additively printed electronics on flexible substrates. Aside from device flexibility, the usage of flexible electronics leads to weight and bulk miniaturization of the product leading to compact and sleek devices. In our previous works, we have successfully studied the effect of mechanical stresses on flexible batteries and their integration into the flexible format via battery lamination. However, in addition to the battery, the battery charging circuit is a key component that must be transferred from a rigid PCB to a flexible format. This study aims to employ electrically conductive ink to print a linear battery charging circuit on a flexible polyimide substrate using different additive printing technologies, namely, aerosol jet printing and direct ink writing (DIW). In aerosol jet printing, both the ultrasonic (AJU) and pneumatic atomization (AJP) technologies have been used for depositing ink, and their subsequent results have been compared. COTS have to be attached to the circuit using electronically conductive adhesives (ECA). The flexible charging circuit has been compared for the print platforms of aerosol-jet printing and direct-write during charging-discharge cycling of the circuit.
Effect of Property Evolution of Doped and Undoped SnAgCu Solder Alloys Under Shock and Vibration
Authors: Lall Pradeep , Yadav Vikas , Suhling Jeff , Locker David 
Published: December 2022

Abstract
Electronics may be required to operate in harsh environments in automotive, aerospace, and defense applications. Solder interconnects in harsh environments may be subjected to extremely-low and high temperatures in the range of −65C to +200C in conjunction with significant strain loads. Furthermore, electronic assemblies may be subjected to extended periods of non-climate-controlled storage prior to deployment. Prior studies have shown that lead-free solder materials continue to evolve under varied thermal loads, leading to deterioration in mechanical parameters such as Ultimate Tensile Strength and Elastic Modulus. The material characteristics for non-linear modeling and reliability prediction are required for risk minimization with the use of new alloy formulations in high-reliability applications. The current work fills this state-of-the-art gap by measuring the mechanical characteristics of undoped SAC105 and doped SAC-Q solder alloys at low operation temperatures (−65°C to 0°C) at high strain rate after varied thermal aging periods up to one year. In addition, the evolution of Anand parameters for SAC solder alloys after prolonged thermal aging has been studied. The Anand model’s reliability has been assessed by comparing experimentally observed data with forecasted data using determined model constants for both solder alloys. The Anand parameters were applied in a FE-framework to simulate drop events for a ball-grid array package on a printed circuit board assembly.