bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and Numerical Investigation of Single-Phase Liquid Cooling for Heterogeneous Integration Multi-Chip Module
Authors: Gharaibeh Ahmad R. , Soud Qusai , Manaserh Yaman , Tradat Mohammad , Sammakia Bahgat 
Published: November 2023

Abstract
The variety of new electronic packaging technologies has grown significantly over the last 20 years as a result of market demands for higher device performance at lower costs and in less space. Those demands have pushed for heterogeneous packaging, where computer chips with different stack heights are closely packed, creating non-uniform multicore chip heat flux and temperature and additional challenges for thermal management. Without implementing an appropriate thermal management strategy for heterogeneous packages, large temperature gradients can be observed within the package, which would increase the thermal stresses on the chip and raise reliability issues. Therefore, removing excessive heat flux will improve the reliability and efficiency of those electronic components. The development of high-heat flux applications is straining the capabilities of air-cooling systems, which are nearing their limitations. Single-phase liquid cooling methods have proven to be reliable, usable, and energy-efficient methods for cooling high-heat flux devices. With the introduction of packages with multiple-chip modules (MCMs), the cold plates of future generations are expected to handle multiple hot spots at the same time. To enable the effective removal of heat from the chips, special cold plate designs for each type of package are required. Many methods may be used to improve thermohydraulic performance, including the use of improved fin designs, flow restriction to breakdown the boundary layer, and the integration of mixing mechanisms to improve the mixing between the fluid and channel walls. To mimic this real-life scenario of such packaging in high-heat flux applications, an experimental setup was designed and built. The design of the new experimental setup consists of four identical 1.2 cm × 1.2 cm ceramic heaters, each of which is connected to a separate power supply and can reach a heat flux of 140 W/cm2. Accordingly, this mock package is capable of delivering different power levels to mimic different multicore microprocessor conditions. To give the heater the ability to move precisely in the x, y, and z directions with high precision, each heater is mounted to an XYZ linear stage. Deionized water (DI) was used as the working fluid, and a commercially available pin-fin heat sink was used to run the initial steady-state tests on the experimental rig. The tests showed how different flow rates at a constant fluid temperature and input power affect the temperatures of the heaters and the thermohydraulic performance of the heat sink. In addition, a three-dimensional numerical model has been developed and validated with experimental data in terms of heat sink pressure drop and temperatures of the heaters.
Characterization of SAC305 Solder Joints Under Elevated Current, Temperature, and Varying Shear Stress Conditions
Authors: Ruby Collin , Huitink David R. 
Published: November 2023

Abstract
With the densification and increased power and operating temperatures of power electronics, solder joint reliability is increasingly important to study at high temperature, current, and mechanical stresses. This paper demonstrates the application of an accelerated stress test using a novel combined loading apparatus where a constant shear stress is applied to a test sample in an oven, with an applied constant current. Average shear stress is varied for three conditions, and it is demonstrated that increasing shear stress reduces lifetime of the solder joints. Cross-sectioned solder joints show corroboration between resistance measurement and joint failure. Further studies will develop a combined stress reliability model, and will include varying temperatures and constant current, as well as the individual measurement of the solder spheres in the circuit. High temperature solder alloys such as gold tin (AuSn) will also be considered.
Reliability of Copper Inverse Opal Surfaces for Extreme-Heat-Flux Micro-Coolers in Low-Global-Warming-Potential Refrigerant R-1233zd Pool Boiling Experiments
Authors: Kekelia Bidzina , Wu Qianying , Narumanchi Sreekant , Major Joshua , Moreno Gilbert , Asheghi Mehdi , Dede Ercan M. , Palko James , Goodson Kenneth 
Published: November 2023

Abstract
This paper explores copper inverse opal (CIO) surface reliability in pool boiling experiments in water and a new, low-global-warming-potential (GWP = 1) hydrofluoroolefin (HFO) refrigerant R-1233zd. The CIO-based structure is intended to develop enhanced two-phase heat transfer surfaces for extreme-heat-flux (∼1 kW/cm2) micro-coolers. In this study, a limited number of pool boiling experiments were performed using water and HFO-1233zd fluid, and the reliability of the CIO-based surfaces was evaluated. Critical heat flux (CHF) values in HFO-1233zd at 40°C–45°C saturation temperatures and the corresponding saturation pressures were also measured. The CHF values with the refrigerant are significantly lower compared to those with water, but the refrigerant allows for a wider usable temperature range in the end application of the micro-coolers and is not limited to data centers with controlled ambient conditions.
Reliability experiments with CIO surface samples — involving pool boiling with water on the CIO surfaces for approximately 48 hours and with HFO-1233zd for 144 hours — showed no structural degradation of the enhanced surface or any significant performance drop in heat transfer coefficients. The CIO surface samples in water were oxidized, most likely due to the presence of air in water and in the experimental vessel.
Water Entry Dynamics of Avian Inspired Divers
Authors: Boom Bart , Truscott Tadd , Fish Frank , Summers Adam , Habtour Ed 
Published: November 2023

Abstract
The mechanics of water entry has been investigated extensively for rigid and deformable media, for a wide range of engineering applications. Limited attention has been paid to understanding the water entry process of structural systems with both rigid and deformable components. Inspired by diving animals such as the gannet, the paper experimentally investigates the dynamic characteristics of diving systems (divers) with different springs and head shapes. While the body shape plays an important role in dissipating the impact energy due during water entry, introducing springs into the neck assembly of a rigid diver reduces its maximum impact acceleration and the jerk by more than 50%, regardless of the tested head shapes. The experimental investigation examines the water entry performance of two diving systems: round and cone head. The effect of the stiffness of water-entry mechanics of each system is compared for rigid (no spring), firm spring, and soft spring, totaling six experimental cases. The impact velocity ranges from approximately 3.1 to 5.9 m/s. Introducing rigid-deformable interfaces into the design of a diving system holds great promise in improving the impact survivability of the system.
A Novel Design of Shape-Memory Alloy Actuated Grippers
Authors: John Benjamin , Schubert Thomas , Casper Matthias , Karl Tino , Pagel Kenny , Drossel Welf-Guntram 
Published: November 2023

Abstract
Given the increasing requirements for enhanced performance, accuracy, space efficiency and complexity in industry, there is a need for robots and industrial grippers to become faster, lighter, and more precise. Moreover, due to various reasons including energy efficiency concerns, there is a growing demand for compressed air-free production or, at the very least, severely curtailed compressed air usage. To address this challenge, this paper introduces a novel approach for industrial grippers that employs shape memory wires, leveraging injection molding automation as a specific use case. Three different concepts of implementing a gripping mechanism were developed, considering the functional and structural degradation of shape memory wires during the design process to meet the requirements throughout its entire cyclic lifetime. Subsequently, a characterization study was conducted on the manufactured gripper system to evaluate its performance. To enable a comprehensive evaluation, a control strategy was devised prior to the study, with the objectives of preventing thermal overheating, enhancing dynamics, and achieving a substantial reduction in power consumption.
Environmental Tests of a Parabolic Self-Deployable Tapespring Boom for CubeSat Applications
Authors: Mhadgut Deven , Thomas Patrick , Du Minzhen , Phoenix Austin , Davaria Sheyda , Black Jonathan 
Published: November 2023

Abstract
The need for composite booms in deployable space structures is ever-increasing. This study aims to investigate the effects of environmental conditions on the material properties of a self-deployable carbon fiber boom with a parabolic cross-section. A similar boom will fly as the primary payload on Ut ProSat-1 (UPS-1), a 3U CubeSat designed and manufactured by students at Virginia Tech. The boom will be deployed repeatedly at different locations along the spacecraft’s orbit. In addition, the boom has a flexible circuit near its tip. This circuit houses an inertial measurement unit (IMU) to measure the acceleration experienced by the boom during and at the end of each deployment sequence. A second IMU embedded on the payload control module near the root of the boom measures the vibration response at that location. The transfer function between these two IMUs will give qualitative and quantitative information about the deployment shock perceived by the CubeSat chassis. The on-orbit data will help validate the data obtained from the ground experiments described here. The boom was deployed inside a Tenney environmental chamber to simulate the space environment. The thermal cycling was typical, with hot and cold survival cycles going from 4°C to 70°C, followed by a series of operational cycles with dwell periods at each. A low vacuum of 9 Torr was maintained throughout the test. The effect of temperature on the deployment velocities and shocks has been presented here. The same tests were performed with the TVAC chamber door open, and the differences were noted. These results will provide insight into the characterization of NASA’s tape springs and aid in making informed decisions for future missions.
Development of a Laser Vibrometer-Based Shear Wave Sensing System for Characterizing Mechanical Properties of Viscoelastic Materials
Authors: Cai Bowen , Shen Liang , Pei Zhe , Li Teng , Li Jiali , Bo Luyu , Du Yingshan , Tian Zhenhua 
Published: November 2023

Abstract
Characterizing the mechanical properties of viscoelastic materials is critical in biomedical applications such as detecting breast cancer, skin diseases, myocardial diseases, and hepatic fibrosis. Current methods lack the consideration of dispersion curves that depend on material properties and shear wave frequency. This paper presents a novel method that combines noncontact shear wave sensing and dispersion analysis to characterize the mechanical properties of viscoelastic materials. Our shear wave sensing system uses a piezoelectric stack (PZT stack) to generate shear waves and a laser Doppler vibrometer (LDV) integrated with a 3D robotic stage to acquire time-space wavefields. Next, an inverse method is employed for the wavefield analysis. This method leverages multi-dimensional Fourier transform and frequency-wavenumber dispersion curve regression. Through proof-of-concept experiments, our sensing system successfully generated shear waves and acquired its timespace wavefield in a customized viscoelastic phantom. After dispersion curve analysis, we successfully characterized two material properties (shear elasticity and shear viscosity) and measured shear wave velocities at different frequencies.
Active Implant System Based on SMA Actuators for Improved Bone Fracture Healing
Authors: Welsch Felix , Kirsch Susanne-Marie , Ehl Lukas , Britz Rouven , Pohlemann Tim , Ganse Bergita , Seelecke Stefan , Motzki Paul 
Published: November 2023

Abstract
Shape memory alloys (SMAs) are an attractive technology in actuators and sensors because of their versatile geometry, low weight, high energy density, and low cost.
Recent scientific research found that a switchable stiffness of an implant for bone fracture treatment with individual stimulation patterns to be applied to the fracture site may improve the patient’s healing process.
The first intelligent implant system was developed and realized. This active implant system consists of two actuation mechanisms. The first SMA actuator system generates a switching capability between rigid and soft states in cooperation with an incompressible element. A second set of SMA actuators generates controlled stimulation of the fracture site in the soft implant state by contracting and restoring with an adaptable stroke.
This work first introduces the mechanism of the active implant with a short overview of the mechanical parts. Next, the novel batterie-driven electronic control unit is presented with its realized miniaturized PCB, and the user interface is introduced, enabling wireless control and monitoring via the internet. Following the manual measuring setup, the demonstration case is presented, which is also equipped with an electronic control unit and the terminal where the user interface allows the control of the implant.
Systematic Thermo-Mechanical Validation of Numerous Tensile-Loaded NiTi Wire Bundles Used for Elastocaloric Heating and Cooling
Authors: Kirsch Susanne-Marie , Welsch Felix , Ehl Lukas , Louia Franziska , Seelecke Stefan , Motzki Paul 
Published: November 2023

Abstract
Nickel-Titanium (NiTi)-based shape memory alloys (SMAs) enable new sustainable and environmentally friendly solid-state heating and cooling technologies. Elastocaloric (EC) heat pump systems exploit superelastic SMAs as a non-volatile, inflammable, and non-global-warming refrigerant, in contrast to the well-established vapor compression technology. The high specific latent heat released or absorbed during mechanical loading or unloading of the SMA material leads to a high temperature change in the material. As a result of the small required work input to induce the phase transformation, a high coefficient of performance (COP) can be achieved by this technology. The potential of these alloys can be exploited through an adequate thermodynamic cycle, efficient mechanical system design, and choice of suited EC materials.
A fully functional continuous operating EC heat pump system based on SMA was developed and realized recently. The EC heat pump system comprises 24 thin wire bundles of 30 wire segments in one bundle. To assist the design process of an optimized device with given performance and efficiency requirements, the air-cooling behavior of single wires and simple bundle arrangement has been analyzed, and intensive parameter studies on different airflow rates have been performed.
Regarding validating the EC heat pump system, a reproducible manufacturing process is presented for the first time, which supports the installation of at least 720 SMA segments in the same thermo-mechanical state.
This work introduces the bundle fabrication process for the first time and validates it by comparing the key thermo-mechanical values of 135 SMA bundles.
The Effects of Electroplating on the Mechanical Properties of Additively Manufactured Structures
Authors: Simonson Kevin , Vyshniakova Kateryna , Nawrocki Robert , El-Shahat Adel , Newell Brittany 
Published: November 2023

Abstract
3D printing, using fused deposition modeling (FDM) has become a staple in the prototyping process because it allows engineers and designers to manufacture parts within a matter of hours instead of days. FDM printing works by melting and extruding plastic filament through a heated nozzle to build a 3D object layer by layer. However, due to the nature of the additive process, parts often fail when placed under loads that they might be subjected to during testing; especially when the loads are applied to the specimen perpendicular to the layer lines. These failures often slow down or halt the iterative engineering process. This work aims to explore strengthening 3D printed parts using an electroplating process typically used to add conductive properties to the plastic material. Tensile testing dog bones that comply with ASTM D638 were printed using an off-the-shelf FDM printer. Specimens were printed parallel to the build plate, at a 45-degree angle from the build plate, as well as perpendicular to the build plate using both non-conductive Polylactic Acid (PLA) filament as well as conductive PLA. Specimens printed in the non-conductive PLA were manually painted with a conductive paint prior to electroplating. Conductivity tests were completed on the specimens before the electroplating process to study its effect on the process. The printed specimens were then subjected to an abrasive sanding process to aid in adhesion of the thin metal layer desired followed by a cleaning in distilled water. The electroplating process requires submerging the specimen to be electroplated as well as the desired metal in an electrolyte solution for an extended period. The specimens will act as an anode and be wired to the negative terminal of a power supply while the desired metal will act as the cathode wired to the positive terminal. Using a single column tensile tester, the specimens were subjected to the testing method provided in ASTM D638 to find the maximum load at failure for all the samples. A statistical analysis was conducted and found that difference of tensile strengths existed between the electroplated and non-electroplated parts where the electroplated parts were on average 20% weaker. While electroplating did not strengthen the 3D printed parts it did add conductive properties to them which gives designers more options when that is a property desired.
Nebula: A Flexible, Solid-State Swimming Robot Enabled by HASEL Actuators
Authors: Hess Isabel , Musgrave Patrick 
Published: November 2023

Abstract
After millions of years of evolution, ocean creatures have mastered the underwater environment. In human interactions with the underwater world, unmanned underwater vehicles (UUVs) are needed for applications where human divers are impractical or at great risk such as exploration of remote locations or the deep ocean. Current propeller-driven UUVs stand to gain greater efficiency and maneuverability by mimicking underwater creatures. Biological fish outperform the state-of-the-art bio-inspired UUVs, but it has been shown in hydrofoil literature that tailoring chordwise flexibility can improve swimming performance across several metrics. In this paper we aim to integrate chordwise flexibility and integrated soft actuators to demonstrate a soft robotic propulsor which better mimics the structure and capability of fish.
Inspired by cartilaginous body-and-caudal-fin (BCF) fishes like sharks, we built a soft robotic fish from compliant components with embedded smart actuators. The robot’s body is made of a 3D printed rubber skeleton and electro-hydraulic contracting-pouch actuators embedded in compliant silicone. The actuators used were hydraulically-amplified, self-healing electrostatic (HASEL) artificial muscles placed in an antagonistic configuration across the spine to produce lateral body contractions. We tailored the stiffness distribution of the body to passively induce BCF swimming kinematics at the caudal fin in response to actuator contractions in the main body. In this paper, the design and fabrication of the soft robot is described and its underwater structural dynamics are characterized with experimental testing in quiescent water. Full-body high speed videos of the robotic fish were taken at varying actuator input voltage and frequency to quantify its dynamic response. We show that the robot’s compliant body deforms like a biological fish and is capable of tail-beat speeds up to 73 mm/s. This flexible, joint-less design with embedded actuation is a step toward fieldable, lifelike bio-inspired UUVs for the future of underwater robotics.
Classifying Soil Saturation Levels Using a Network of UAV-Deployed Smart Penetrometers
Authors: Chowdhury Puja , Satme Joud N. , Yount Ryan , Downey Austin R. J. , Khan Sadik , Imran Jasim , Micheli Laura 
Published: November 2023

Abstract
Levees are built to safeguard human lives, essential infrastructure, and farmland. However, failure of levees can have catastrophic impacts due to a fast rate of inundation in areas protected by levees. Earthen levees are prone to failure due to excessive moisture content that reduces the shear strength of the soil. The use of levee monitoring systems has demonstrated the ability to reduce the likelihood of failure by creating maps that depict the saturation levels of the surface of the levee, both in terms of space and time. By utilizing extensive sensor networks to continuously monitor these geo-infrastructure systems, the structural deterioration attributed to changing climate can be studied. Measuring environmental parameters surrounding such structures provides insight into the potential stressors that cause structural failure. Steps can then be taken to mitigate those effects on the levees and maintain structural integrity. However, the massive scale of levees makes it difficult to monitor with conventional wired sensors. This paper presents a preliminary investigation into the development and validation of UAV-deployable smart sensing spikes for soil conductivity levels in levees, which is a measurement modality for determining soil saturation levels. For this work, Gaussian process regression (also known as kriging) is used to model the soil saturation levels between sensing spikes obtaining a continuous moisture map of the levees. The expanded data is then categorized using a clustering-based machine learning approach with conductivity data from sensing spikes as model inputs. The machine learning model output is sorted into three categories: dry, partially saturated, and saturated soil. The findings of a laboratory study are presented, and the implications of the raw and expanded data are discussed. This work will aid in predicting potential levee failure risks and maintenance requirements based on the analysis of the soil conditions using a network of smart sensing spikes.