bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Roughness Repeatability Analysis for Multi-Build Overhang Parts in Powder Bed Fusion Additive Manufacturing
Authors: Yang Zhuo , Hong Gi Suk , Lu Yan , Hu Chun-Chun , Yang Haw-Ching , Lane Brandon 
Published: November 2024

Abstract
Additive manufacturing (AM) has been evolving from rapid prototyping towards applications in high-volume production and mass manufacturing. However, achieving consistent quality and meeting industry standards remains a challenge that hinders AM industrialization. While most traditional manufacturing processes have established process control for part quality management, the complete understanding of part quality repeatability across builds, machines and processes is still missing. Hence, quality-related features such as surface roughness cannot be consistently reproduced for mass production. This study initiates the process of investigating laser powder bed fusion part repeatability in terms of surface roughness, based on the measurements conducted at the National Institute of Standards and Technology (NIST). The research compares the roughness of different surfaces of a single AM part, identical parts from a single build, and parts fabricated from two separate builds. The part has designed surfaces varying from up-skin surfaces with different conditions to down-skin surfaces of overhangs. The roughness measurements based on XCT data reveal that average roughness, Ra, of different types of surfaces is distinguishable from each other. It’s also observed that the roughness of up-skin surfaces consistently exhibits lower values compared to down-skin surfaces. However, inherent variations between builds pose challenges to achieving full repeatability. Analysis indicates that the roughness of all four parts from the first build is lower than that of the 16 parts from the second build with the same process settings and feedstock material. Achieving repeatability becomes increasingly difficult when process, machine or material variations between builds are present.
A Vision-Based Health Inspection of Power Line Conductors for the Mobile Damping Robot
Authors: Kang Hyun Myung , Yoon Ranhee , Barry Oumar 
Published: November 2024

Abstract
Ensuring the structural integrity of the overhead power line conductor is crucial for maintaining the safety and reliability of the electrical transmission system. Exposure to environmental hazards like moisture, dust, and Wind-Induced Vibrations (WIV) can lead to defects and corrosion in power line conductors, which are primary contributors to fatigue and shortened lifespan. Thus, this paper presents a vision-based health inspection of power line conductors for a maintenance robot. The method involves image filtering techniques such as Sobel, Scharr, and Gray-scale Variance Normalization (GVN). After filtering the image, row and column analysis is conducted to identify relevant patterns that distinguish healthy and unhealthy conductors, utilizing histograms for data representation. From the histogram data analysis, 10 features were chosen from observation. Subsequently, the collected image data is classified into either healthy or unhealthy categories through supervised machine learning models, including Random Forest (RF), Multi-Layer Perception (MLP), and Gradient Boosting (GB). The best combination of features is extracted to optimize each machine-learning models accordingly. Experimental results validated the effectiveness of our method, which has been specifically fitted for the Mobile Damping Robot (MDR), presenting its potential for enhancing power line maintenance.
Parametric: Empowering In-Situ Parametric Modeling in Augment Reality for Personal Fabrication
Authors: Duan Runlin , Hu Xiyun , Liu Min , Shi Jingyu , Ramani Karthik 
Published: November 2024

Abstract
Parametric modeling software is a powerful design tool for controlling dimensions, accessing high-quality model libraries, and iterating on design concepts. However, its steep learning curve, complex user interfaces, and lack of spatial understanding can hinder novice users from creating reusable and precise solid models. To overcome these barriers, we introduce pARametric, an augmented reality (AR) system that provides an effortless parametric modeling experience in situ. This system features an immersive sketching platform for freehand sketching, a transformer-based parametric sketch construction algorithm, and an AR interface that offers intuitive hand-to-virtual geometry interaction for 3D modeling operations. In pARametric, a novice designer without experience in 3D modeling can create parametric models for personal fabrication. Our system uses environmental information as design references to make decisions about structure, dimension, and shape. The system allows users to express their design intents by sketching in freehand rather than mastering the sophisticated operations of existing modeling software. We also incorporate widely used 3D modeling features such as extrusion, revolution, sweep, and mirror to create a wide variety of models. In a user study with 8 participants, we discovered that novice designers see great potential in pARametric to enhance their capabilities and willingness to engage in parametric modeling for design. We further discuss how our system can be integrated into traditional parametric modeling workflows to benefit a wider range of designers for visualization and collaboration on sophisticated design tasks.
Evaporative Thermal Management of Batteries in Electric Vehicles Using Flexible Structures
Authors: Bouzidi Myriam , Kim Junyoung , Goldman Jonathan , Joshi Yogendra 
Published: November 2024

Abstract
As the capacity of electric vehicle (EV) battery packs increases and recharging times are reduced, effective battery thermal management becomes a key challenge. When exposed to elevated temperatures and non-uniform thermal conditions, insufficient heat dissipation within the battery module can detrimentally impact both its operational lifespan and performance, posing a potential risk of thermal runaway. Therefore, by reducing maximum temperatures and enhancing temperature uniformity through the batteries in order to improve lifespan and performance. Furthermore, depending on the specific battery cell technologies employed in EVs, battery swelling also emerges as a significant challenge as it can increase heat generation and drops in battery life. Thus, this paper develops a two-phase flexible battery thermal management system, enhanced with a copper microstructure, using a dielectric coolant (HFE-7000) to mitigate battery surface temperatures. The heat transfer performances were experimentally studied in a mass flow rate range of 4.5 g.s−1 to 11 g.s−1 with representitive heat dissipation values between 10 W.m−2 and 1.4 W.m−2 and shows the ability of the system to maintain average surface temperatures in a the battery optimal operational range between 25°C and 35°C.
Commissioning and Thermohydraulic Characterization of a Single-Phase Liquid-Cooled High-Density Data Center Rack
Authors: Heydari Ali , Kisitu Deogratius , Ortega Alfonso , Eslami Bahareh , Shahi Pardeep , Tradat Mohammad , Costello James , Margaritondo Benjamin 
Published: November 2024

Abstract
High-density data centers are currently increasing in demand. As data centers grow in power and complexity, traditional air cooling is no longer adequate for handling contemporarily increasing HPC and AI workloads. Liquid cooling is emerging as an efficient solution for high-density data center cooling, with a host of benefits, including reduced costs, higher sustainability, and the ability to handle higher power densities. In the current work, a single-phase liquid-cooled test high-density rack was assembled, experimentally commissioned, and characterized at full design power. The rack has four servers, each with eight (8) high-power graphic processing units (GPU) thermal test vehicles (TTV) and four (4) low-power switch TTVs. Each TTV was instrumented with Type-T thermocouples to measure the case temperatures. Each GPU TTV was powered at 1000 W and each switch TTV was powered at 250 kW. Liquid-cooled cooling loops (each consisting of eight (8) GPU cold plates and four (4) switch cold plates) were attached to each of the server TTVs. The inlet and outlet of each cooling loop were instrumented with calibrated thermistors, pressure sensors, and magnetic-inductive flow meters to measure the cooling loop’s inlet and exit fluid temperatures, pressure drop, and flow rates, respectively. Two of the test servers were reliability servers and the other two were the thermal verification server and hydraulic verification server. The thermal verification server was hugely instrumented with numerous thermistors to verify the inlet and outlet fluid temperatures of each cold plate. The hydraulic verification server had multiple magnetic-inductive flow meters to verify flow distribution in each cold plate on the cooling loop. Results show that at the coolant [25% propylene glycol/water (PG-25)] supply temperature of 32 °C and full design power, the average GPU TTV case temperature per TTV was close to 64.5 °C. The mean switch heater Tcase is generally identical per server TTV and is about 53.5 °C, with a mean standard deviation of less than 0.7 °C. The energy balance on a rack reveals that about 97.1% of the heat dissipated by server TTVs was rejected to primary side/facilities chilled water.
Capillary-Based Two-Phase Cooling for High Power Density Power Electronics
Authors: Lin Yujui , Kwon Heungdong , He Yini , Chen Hao , Gupta Man Prakash , Degner Michael , Asheghi Mehdi , Mantooth H. Alan , Goodson Kenneth E. 
Published: November 2024

Abstract
Effective thermal management is crucial in power module design, significantly influencing the cost, performance, and reliability of the traction inverters. As we strive for greater power density and smaller form factors, innovative thermal solutions become imperative. In this study, we explore a two-phase cooling method enabled by substrate-embedded microchannels for the power module. We utilize surface enhancement features at the substrate microchannels to enable capillary-driven flow for passive liquid supply. We find that the two-phase cooling in our study leads to a high heat flux removal rate of 400 W/cm2 at a low superheat of 10 °C. Moreover, the coolant flow rate is less than 1 g/min, nearly 50 times lower than the pumped flow-based two-phase microcoolers. We also investigate the implementation of the two-phase cooling method into a power module-like package. A systematic study of packages with 1 and 4 chips is conducted and verified with the simulation. The impact of the condenser and vapor recovery features on the cooling performance is also studied. The proposed two-phase cooler can overcome the typical issues encountered in two-phase cooling, such as flow instability and dry-out.
Evaluation of Warpage Deformation in Semiconductor Device Packaging Process
Authors: Yagi Taiju , Yu Qiang , Shimada Haruyuki , Yanaka Yuichi , Masuko Takashi 
Published: November 2024

Abstract
Compression molding is gaining attention as a next-generation method for molding high-density and thinner semiconductors, driven by the increasing demand for products like smartphones and tablets. Unlike traditional methods, it involves uniformly supplying granular resin to the substrate to minimize resin flow, thus enabling batch encapsulation of large substrates without product variation or resin anisotropy. However, warpage during the semiconductor packaging process poses a technical challenge, especially for large carrier substrate molds. This warpage, caused by differences in the Coefficient of Thermal Expansion (CTE) between the substrate and encapsulant, as well as mold shrinkage effects during curing, can lead to defects. To address this, researchers have studied material combinations to minimize warpage, but predicting warpage for large and thin substrates has been difficult. This study aims to develop a Finite Element Method (FEM) simulation-based method to predict warpage during the packaging process, streamlining the selection of encapsulating materials. Through experimentation and simulation, the team aims to identify patterns of warpage, investigate the effects of factors such as resin cure shrinkage from the substrate and resin combination on warpage, and ultimately improve the consistency and predictability of the packaging process.
Effects of Package Position and Constraint Conditions on Fatigue Life of QFP Interconnect Structure Under Random Vibration
Authors: Shimamura Nozomi , Yu Qiang 
Published: November 2024

Abstract
In this paper, the effects of board restraint conditions and package location on the fatigue life of quad flat packaging (QFP) interconnect structures under random vibration loading for automotive applications are evaluated using the finite element method. Four different restraint conditions of the board model were used to reproduce the natural frequencies of the board, and six different positions of the package were analyzed and evaluated. The results show that the fatigue life depends on the relationship between the first-order natural frequency and the patterns of power spectral density (PSD) of the input. In addition, it was found that the maximum principal strain of printed circuit board (PCB) directly under the center of package had a significant effect on the maximum damage location and its damage value in the lead area. The relationship between the package mounting position and board restraint conditions and the degree of damage was found to be regular.
Comprehensive Analysis of Two-Phase Flow Boiling for IT Equipment Cooling: A System and Component-Level Approach
Authors: Najjari Mohammad Reza , Turner Cam , Mostafavi Kamal 
Published: November 2024

Abstract
As part of CoolIT System Inc.’s ongoing assessment of liquid cooling technologies, the company performed an in-depth study of two-phase direct liquid cooling (2P DLC). The study focused on the technology’s commercial viability from a system design and operation perspective using a 2P DLC system set up in CoolIT’s Liquid Lab™ Innovation Centre coupled with extensive industry research.
This paper outlines the study’s results, supplemented with research, and describes the inherent challenges system developers must address when developing a two-phase system. We examine how pressure drops affect system performance and evaluate the advantages and disadvantages of arranging components in a series configuration. The authors also examine the operational considerations of using refrigerants.
In sum, the higher costs associated with the refrigerant and equipment required for high working pressures in a 2P DLC system, greater health and safety risks as well as legal liability risks, outweigh the perceived performance benefits for industry-wide deployments. This is especially true given the excellent thermal performance of simpler, more cost-effective single-phase direct liquid cooling (1P DLC).
While the authors conclude that 2P DLC is not yet a viable solution for mass market production and adoption, further investigation is warranted to determine whether it is applicable for specific IT equipment applications.
Validation and Translation of Process Monitoring Tools for Commercial Aerosol Jet Printing Systems
Authors: Rurup Jeremy D. , Secor Ethan B. 
Published: November 2024

Abstract
Aerosol jet printing is a promising method for additive electronics packaging, offer digital, non-contact deposition of functional materials with resolution below 20 microns. However, process reliability remains a key challenge in translating this method to production environments. In recent years, we have developed a real-time process monitoring technology for aerosol jet printing using light scattering from the aerosol stream. In this work, we aim to translate this capability to commercial printing systems. Experimental efforts use two different commercial printing systems, namely Sprint and Decathlon systems from Optomec. Moreover, while prior work focused exclusively on ultrasonic atomization, we will discuss results for both ultrasonic and pneumatic methods for droplet generation. The comparison across printing systems and atomization methods provides valuable insight for the generality of the process monitoring approach. Alongside routine testing to validate the process monitoring method over timescales of tens of minutes, we show that variability in the measurement on the seconds timescale can serve as an indicator for nonidealities in the print process. Overall, this technique advances the utility of aerosol jet printing for electronics packaging applications by improving process reliability in prototyping and production, providing insight on fundamental mechanisms, and establishing a potential approach to efficient and more standardized material and process development.
Thermal Performance of Low GWP Dielectric Fluid for Two-Phase Immersion Cooling
Authors: Yuksel Anil , Pottker Gustavo , Van Wassen Abigail , Brandt Drew 
Published: November 2024

Abstract
Two-phase immersion cooling has become one of the most promising technologies for cooling servers and chips in data centers due to its superior cooling performance. In this work, the thermal performance of a new low-global warming potential (GWP) dielectric fluid, Opteon™ 2P50, was evaluated using an Intel Sapphire Rapids thermal test vehicle (TTV) coupled with a commercially available microporous boiler plate with a design power of 200–600W. Tests were carried out at power levels from 300–1000W, in three orientations and with two different thermal interface materials (TIMs) while the fluid was always kept near saturated conditions. For the vertical and 45° orientation, the case-to-fluid thermal resistance reached a minimum of about 0.02 K/W at about 400W or a heat flux of around 16 W/cm2. At the maximum boiler plate design power of 600W (24 W/cm2), the case-to-fluid thermal resistance still ranged from 0.023–0.026 K/W. It was estimated that the critical heat flux was reached between 900 and 1000W, or 36–40 W/cm2, for the vertical orientation. Results also showed the case-to-fluid thermal resistance was lower for the horizontal than the vertical orientation, consistent with previous studies. Finally, additional experiments demonstrated that indium pad yields a much lower case-to-fluid thermal resistances than the thermal grease tested.
Performance and Reliability Comparison of Thermoformed, Screen-Printed Structures on Polycarbonate (PC) and High Impact Polystyrene (HIPS) Substrates Under Sustained High Temperatures for In-Mold Electronics
Authors: Lall Pradeep , Kulkarni Shriram , Miller Scott 
Published: November 2024

Abstract
In-mold electronics offers a path toward reducing the carbon footprint in automotive platforms through weight reduction. This technology enables the integration of human-machine interfaces directly onto automotive surfaces using additive printing processes. Among these processes, screen printing is a promising method due to its suitability for large surface areas and high throughput efficiency. This paper sets out to evaluate and compare the electrical and mechanical performance of additively screen-printed, thermoformed circuits on Polycarbonate (PC) and High Impact Polystyrene (HIPS) substrates under prolonged high temperatures. The research aims to characterize the long-term reliability and stability of these circuits under significant thermal stress and to analyze their failure modes and mechanisms. The methodology involves screen printing two types of test structures — Traces with Pads and Circuits — on both PC and HIPS substrates. In this paper, results are presented on SMD attachment of components on IME Circuits. The interaction of high-temperature processing with circuit performance has been studied.
Evaluation of Printed Logic Circuits With Additively Packaged GaN Bare Die Devices at High Temperatures
Authors: Lall Pradeep , Soni Ved , Karakitie Daniel , Miller Scott 
Published: November 2024

Abstract
Current electronics packaging is not designed to sustain and operate at high temperatures above 150°C. However, in specialized applications, operation at extreme high and extreme low temperatures can be a requirement. Since the current electronics substrates are not high-temperature qualified, low-temperature co-fired ceramic (LTCC) can be used as a substrate for extreme-high-temp capable electronic circuits. Also, since traditional silicon carbide dies and package architectures would not sustain high temperatures, bare gallium nitride dies can be used. In this study, additively printed electronic circuits capable of operation at high temperatures have been attempted to be designed. Copper-clad LTCC has been used as the substrate of choice for fabricating these circuits. The circuit for this study was fabricated using the LPKF U4 Protolaser machine for laser patterning. Components are then attached to the patterned circuit using a transient liquid phase sintering (TLPS) paste, which sustains up to 600°C. The candidate circuit chosen for this study is a full-wave rectifier circuit. The fabricated circuits have been tested in a high-temperature kiln, and their performance is measured using an oscilloscope.
Enabling Reduced Footprint SMT Components in IC Packages: A Simulation-Based Approach for Solder Paste Volume Optimization
Authors: Puliyath Nidheesh , Xie Huxiao , Alcira Cecille , Kothari Nakul 
Published: November 2024

Abstract
The Integrated Circuit (IC) packaging sector is experiencing heightened demand for compact, and efficient packages, driven by advancements in AI and 5G technologies. This necessitates smaller package component footprints and increased component density. For surface mount technology (SMT), solder volume optimization is crucial for component height control and mechanical performance, to ensure device integrity and longevity. Research indicates that solder volume during SMT integration affects joint quality, standoff height and reliability. For the SMT integration, some of the key current challenges in the industry are reducing the size and footprint of SMT components and simultaneously optimizing the solder volume in relation to the reduced size. The use of SMTs on both the die side and the BGA side of the package are also increasingly common. However, existing studies have not sufficiently tackled these complex issues. Additionally, there is a significant research gap concerning the optimization of solder volume for intricate SMT components, like deep trench capacitors (DTC). These gaps provide a potential area for further exploration and advancement in this domain. This paper presents a simulation-based approach for solder paste optimization that can support IC package design and development. Thus, aiming to cut development costs and shorten the time from development to deployment by using the model for proof-of-concept validation. Authors present an energy-based simulation approach for integrating SMT in IC packages, to address current industry design challenges. This approach was validated using two types of Multilayer ceramic capacitor (MLCC) capacitors and a deep trench capacitor (DTC), promising substantial cost and time reductions in package development.