bluuebunny/crossref_metadata_2025_split huggingface dataset:
Innovative Non-Destructive Techniques for Radioactive Waste Packages Monitoring
Authors: Chierici Andrea , Ciolini Riccardo , Lo Frano Rosa , D’Onofrio Antonio , Sabbarese Carlo , Pandalone Antonio , Romoli Mauro , di Meo Paolo , Finocchiaro Paolo , Conti Enrico , Gonella Franco , Andreetto Paolo , Checchia Paolo , Niederleithinger Ernst , d’Errico Francesco 
Published: November 2023

Abstract
A monitoring and surveillance system is a mandatory element to ensure that a radioactive waste disposal facility provides and meets the required level of safety during both its operational and closure periods. In this study an innovative approach for the identification and monitoring of the structural integrity of stored radioactive drums is presented. The activities were carried out in the context of the European Project PREDIS, whose goal is the development of a robust and reliable sensing technology for monitoring and long-term storage of radioactive waste packaging systems.
Specifically, the focus was set on the development of innovative and smart sensor technologies, non-destructive examination tools, and/or devices capable to improve the safety of the storage by minimizing the number of interventions of cemented waste packages. Both conventional and innovative techniques, such as muon-tomography, SiLiF neutron and SciFi gamma detection, or contactless and smart radio transceiver technology provided with radiation monitoring sensors, have been considered and adapted for the use under repository conditions. Indeed, gamma and neutron detection techniques exploit the radiological information coming from inside the drums, while imaging techniques proved to be effective in spotting high density objects embedded inside the concrete: together, they allow to improve safety and security and can provide an early alert on behavioral changes hinting at anomalies in the drums.
Tailoring Nuclear Waste Glass Properties for Joule Heated Ceramic Melter Technique With Bottom Drain Glass Pouring
Authors: Weiser Martin , Willberger Christian , Finck Nicolas , Xiangda Meng , Xiaorui Qu , Jing Zhao , Weisenburger Siegfried 
Published: November 2023

Abstract
Detailed investigations during the glass formulation development for the future Diwopu plant are described. Three different glass formulations were developed including two base glasses for the different waste streams present at Diwopu site and a corresponding Start Glass that allows commissioning of the liquid-fed ceramic melters (LFCM) and later switch-over from glass production operation of the melter to idling mode for maintenance. The waste glasses have to possess similar physical properties to be processed within the same LFCM. Therefore, all three developed glasses were tailored to lie within given margins for rheological and electrical resistivity data as well as to allow a high waste glass loading and high chemical durability. Further in-depth research was conducted to clarify the crystallization behavior of the waste glasses as it is known that the crystallization tendency has to be minimized to exclude relevant impacts on the viscosity. Increase of the viscosity due to crystallization might otherwise lead to unfavorable conditions for the bottom drain up to blockage in the worst case.
The Enhanced Sealing Project (ESP) at the Underground Research Laboratory in Canada: Sixteen Years and Counting?
Authors: Priyanto Deni G. 
Published: November 2023

Abstract
Established in 2008, the Enhanced Sealing Project (ESP) was the final full-scale experiment at the Underground Research Laboratory (URL) in Manitoba, Canada. As of January 2023, the project has been monitoring the evolution and performance of the full-scale composite shaft seal at the URL for over 16 years. The shaft seal was constructed in a 5-m-diameter circular shaft across a water bearing fracture zone at the depth of c. 270 m and comprises of 6-m-thick clay component that is sandwiched between two 3-m-thick concrete components. The clay component was made of 40% (by dry mass) of bentonite and 60% of fine aggregate mixture. This paper highlights the ESP results until early 2023. The ESP results, combined with the URL results from 1980s to 2013, provide 45+ years of unique data sets representing a lifecycle of an underground facility from pre-construction, operation, decommissioning, closure, and post-closure phases. This paper also examines the feasibility of the ESP extension beyond 2023 and proposes additional efforts that will enable to observe the evolution of the seal and URL for the longer term (e.g., several decades).
MPS Method Simulation for Estimating Fuel Debris Distributions Under the Damaged Reactor Pressure Vessel of 1F Unit-2
Authors: Bando Yamato , Yamaji Akifumi , Yamashita Takuya 
Published: November 2023

Abstract
The internal investigations of TEPCO’s Fukushima Daiichi Nuclear Power Station (1F) Unit 2 indicate multiple breaches in the lower head of the reactor pressure vessel (RPV), which led to discharges of molten core materials. In addition, a large enough breach(es) is expected near the vessel periphery, which allowed relocation of a fuel assembly upper tie plate to the pedestal floor. However, the muon radiography indicates that massive fuel debris are still retained within the RPV lower head. This study aims to provide a comprehensive explanation of such observations by considering interactions of the fuel debris with the thermal insulation plates below the RPV lower head at the time of the accident. The Moving Particle Semi-implicit (MPS) method has been developed and pieces of the debris were modeled by rigid bodies to analyze thermal behavior of the fuel debris and their interactions with the insulation plate. The results showed that whether the insulation plate failed or not depended on the initial enthalpy and temperature distribution of the relocated fuel debris on the plate. The results implied that thermal load on the plate was greater below the outer region of the vessel than the central region, because there was larger space between the plate and the vessel for the debris to pileup.
Additively Manufactured Hybrid Two-Phase Cold Plate
Authors: Shaeri Mohammad Reza , Bonner Richard , Catuche Jana 
Published: November 2023

Abstract
The performance of a capillary-driven two-phase cold plate (CP) for thermal management of high heat flux electronic devices was investigated. The CP was a key component of a hybrid two-phase cooling system (HTPCS). The HTPCS operated with the refrigerant R245fa and integrated the benefits of a pumped two-phase cooling with a capillary-driven two-phase cooling. The significance of the present study is to fabricate the CP integrated with evaporator wicks through one single additive manufacturing (AM) process. The CP was a compact enclosure including eight heaters located on both sides of the CP. The evaporator wicks were lattice structures, and individual heater was cooled down by its own evaporator. Compared to the CP without evaporator wicks, the capillary-driven CP (CDCP) led to 39% enhancement in the upper limit heat flux, as well as over 44% improvement in the non-uniformity of the thermal resistance of the CP. The equivalent heat fluxes achieved by the CDCP was 203–212 W/cm2 over areas less than 0.1 cm2. The measured thermal resistances at those ranges of heat fluxes were ∼ 0.16–0.30 K-cm2/W, while operating within a low pumping power below 0.3 W.
Cold Gas Spraying Copper Metal on AlN Ceramics as an Alternative to Thick DBC Substrates for Power Electronics
Authors: Guerrero Margie , Quintero Pedro , Ozdemir Ozan Cagatay 
Published: November 2023

Abstract
This study investigates the use of cold gas spraying (CGS) as a low-temperature additive manufacturing method to bond copper onto aluminum nitride (AlN) substrates for electronic packaging of high-power applications. While direct bond copper (DBC) technique is commonly used, it has limitations due to the large mismatch in coefficient of thermal expansion, which affects substrate reliability. This work employed cold gas spraying (CGS) to mechanically bond Cu on AlN. The study explores the effect of multiple sprays, spray angle and spraying direction on deposition thickness, coating surface roughness, and deposited volume through a factorial design of experiments (DOE). The results, based on optical and scanning electron microscopy combined with profilometry data, showed that coatings sprayed at a 60° angle had a smoother profile topography and less surface roughness than those sprayed at a 90° angle. After depositing 10 layers, a surface roughness (Sa) of around 30 μm and a coating thickness of over 300 μm were successfully attained. These findings provide valuable insights into the processing factors affecting the growth and quality of copper coatings on AlN substrates via multiple sprays, thus enabling the realization of CGS technology as a potential solution to DBC substrates for electronic packaging of wide-bandgap semiconductors.
Thermal and Hydraulic Performance Analyses of Machined and Hybrid Printed Oblique-Fin Cold Plates
Authors: Law Matthew , Soh Sin Liang , Wang Wei , Lee Poh Seng , Lu Wen Feng 
Published: November 2023

Abstract
The computational capabilities of central processing unit (CPU) and graphics processing unit (GPU) are rising steadily with every generation thanks to advancement in electronics and packaging techniques. However, this brings about issues in effective heat dissipation as the thermal design point (TDP) of the chips increases as well. In view of the higher TDPs, traditional air-cooling solutions, such as air-cooled CPU heat sinks and built-in fan modules on the GPU card are no longer sufficient in addressing this problem. This causes the CPU and GPU temperatures to hover very close to their maximum allowable limit. When this occurs, the performance of the chips degrades due to thermal throttling. Thus, the introduction of liquid cooling to high-performance computing (HPC) servers is inevitable due to the above issue. Liquid-cooled HPC servers using finned cold plates not only effectively dissipates higher heat flux but also reduces power consumption of the chip by significantly lowering the chip operating temperature. In this work, the oblique-fin cold plate was fabricated using a hybrid manufacturing technique, whereby the fins were additively manufactured (AM) directly on a solid machined base plate. The fins were fabricated by selective laser melting using copper chromium zirconium, CuCrZr powder, which is a high thermal conductivity copper-based alloy. The base plate, on which the fins were printed, was machined from solid copper. Hybrid printing reduced fabrication time and saves cost, as bulk of the printing time and cost came from the base plate. On the other hand, the benchmark oblique-fin cold plate was machined using wire-cut (WC) electro-discharge machining (EDM), which is a form of subtractive manufacturing. The AM oblique fins reduced material wastage compared to the machined fins. Liquid cooling experiments were conducted on a 1U server running on a 32-core AMD CPU with a TDP of 180 W. Water flow rates were varied between 400 ml/min to 2000 ml/min with an inlet temperature of 25°C. Thermal and hydraulic performance analyses revealed that the hybrid printed oblique-fin cold plate managed to maintain lower CPU temperature compared to the WC oblique-fin cold plate. However, the associated pressure drop penalty was slightly higher due to higher surface roughness of the AM fins. Nevertheless, the pressure drop penalty incurred was justified due to its better cooling performance, as the AM oblique-fin cold plate exhibited higher overall performance when evaluated using the thermal resistance vs pumping power curve. As a result, AM, in particular hybrid printing, can be considered as an alternative to fabricate finned cold plates, especially irregular fin designs that are otherwise not realizable using conventional machining techniques, without compromising cooling performance.
Investigation of Silicon Carbide Embedded Cooling Technology for Compact Electronic Systems
Authors: Wilhite Jarred , Kharangate Chirag 
Published: November 2023

Abstract
A compact, high heat flux cooling design is in development that can enable high-powered electronic systems to achieve greater thermal reliability and sustained functionality for a wide variety of applications. The design and development of this embedded cooling technology involves microfabrication of a 3-D manifold structure in silicon carbide (SiC) which is bonded to a SiC microchannel substrate to form a manifold-microchannel (MMC). The flow manifold geometries in conjunction with the embedded microchannel array provides the MMC with the ability to enable high heat transfer rates while maintaining reasonably low pressure drops, thereby minimizing the pumping power of the system. Microfabrication processes and techniques used to manufacture the MMC are presented. Modeling results are also presented to demonstrate the benefits of the MMC design over traditional cooling designs. This MMC fabricated from SiC is capable of meeting heat dissipation targets of 100 W/cm2 while maintaining thermal resistance below 2 K/W and ΔP within 1 kPa utilizing single-phase working fluid.
A New Low-GWP Dielectric Fluid for Two-Phase Immersion Cooling
Authors: Pottker Gustavo , Van Wassen Abigail , Brandt Drew R. 
Published: November 2023

Abstract
Two-phase immersion cooling (2-PIC) is one the most promising technologies for thermal management of next generation servers and chips. 2-PIC can help data centers dramatically reduce energy and water usage, physical footprint while providing much higher heat rejection rates for chips versus air cooling. Given that many commercial two-phase immersion fluids have limitations of either high GWP, poor dielectric properties or challenges such as chemical stability, a new dielectric fluid candidate (DF-50) is proposed in this paper. Experimental results showed that the dielectric constant and dissipation factor of DF-50 are only about 1.75 and 1 × 10−3, respectively, under frequencies up to 67GHz. A signal integrity analysis of cable and microstrip traces showed that the insertion losses of these components when immersed in DF-50 are almost identical to those in air. The actual thermal performance of multiple GPUs equipped with boiler plates and immersed in DF-50 is also investigated. The total thermal resistance based on the average GPU temperature was estimated to be about 0.04°C/W, with further opportunities for improvement.
Condition Monitoring of Semiconductors Using Wide Band Acoustic Emission Sensors
Authors: Frankhouse Josef , Marsh Jackson , Hu Han 
Published: November 2023

Abstract
Electric vertical takeoff and landing (eVTOL) aircraft require a significant amount of power to operate and fly efficiently over long distances. Nevertheless, long-distance flights of electric vehicles are limited by the energy density of batteries and the specific power of electronics. Mid-voltage power electronics can increase the voltage of the power supply and reduce the current, allowing the eVTOL aircraft to operate more efficiently. However, the breakdown voltage in aircraft is significantly lower than ground due to Paschen’s effect. As such, condition monitoring of power electronics has become critical to the safe operation of eVTOL. In recent years, acoustic emissions (AE) sensors have gained traction within the electronics space, due to their resistance to electromagnetic interference and high temperatures. In this study, acoustic emissions from an integrated circuit are experimentally measured and analyzed for condition monitoring. An AE sensor was applied onto a NE555PCR oscillator placed upon an epoxy substrate to characterize the electromagnetic waves emitted from the device under various input loads. Acoustic emissions were detected upon applying voltage to the oscillator, in which correlates with the output of the device, as well as its input state.
Effect of Thermal Cycling on Interfacial Fracture Toughness of Electronic Mold Compound-to-Substrate Interface Subjected to Monotonic and Fatigue Loading
Authors: Lall Pradeep , Kasturi Madhu 
Published: November 2023

Abstract
Electronics used in automotive underhood applications are subjected to extremely high operating temperatures ranging from 125 to 150°C for up to 10 years or longer over the vehicle’s use-life. Semiconductors in area-array packaging on laminate substrates are encapsulated in electronic mold compounds in microelectronic assemblies to meet unique functional needs. The robustness of the EMC-Substrate interface may also be influenced by the thermal mismatch stresses owing to the differences in the coefficients of thermal expansion between the glass-impregnated epoxy substrate and the silica-filled epoxy. This paper investigates the interface fracture toughness in bimaterial pre-cracked specimens made of PBGAs during thermal cycling exposure. Two EMC materials are subjected to 1000 automotive-grade thermal cycles. The samples are subjected to thermal cycling from −40°C to +125°C. Bi-material EMC-Substrate beam samples are created by polishing the solder balls from PBGA packages. Fracture toughness is measured under exposure to automotive-grade thermal cycling. Interfacial crack initiation, propagation, and failure mechanisms are investigated.
Comparative Study of SMD Components Attached Using Electrically Conductive Adhesive and Magnetically Oriented Anisotropic Conductive Adhesive on Inkjet Printed Structures
Authors: Lall Pradeep , Kulkarni Shriram , Narangaparambil Jinesh , Miller Scott 
Published: November 2023

Abstract
Due to its high resolution and ability to deposit a variety of functional materials, including conductive inks, insulators, and dielectrics, inkjet printing is a viable method for constructing such devices. In this study, the authors sought to examine the electrical and mechanical performance of surface-mounted device (SMD) components mounted on inkjet-printed circuits using two adhesives: Electrically Conductive Adhesive (ECA) and Magnetically Oriented Anisotropic Conductive Adhesive (MOACA). The study is carried out this investigation in two phases. In the initial phase, SMD components such as resistors, inductors, and capacitors were mounted using ECA and MOACA on conductive traces with pads, and their electrical performance was compared to their rated values. In the second phase, the behavior of inkjet-printed Circuits was studied, including Non-Inverting Amplifier Circuit and Schmitt Trigger Circuit. These functional circuits were constructed on polyimide substrates. The researchers utilized silver nanoparticle ink. Evaluation of the electrical and mechanical performance of the circuits was done. Overall, this study gives invaluable insight into inkjet-printed circuits’ electrical and mechanical behavior, particularly in the context of attached components.
Single-Phase Immersion Cooling Multi-Design Variable Heat Sink Optimization for Natural Convection
Authors: Herring Joseph , Gupta Gautam , Lamotte-Dawaghreh Jacob , Bansode Pratik , Agonafer Dereje 
Published: November 2023

Abstract
This paper proposes a computational fluid dynamics (CFD) simulation methodology for the multi-design variable optimization of heat sinks for natural convection single-phase immersion cooling of high power-density Data Center server electronics. Immersion cooling provides the capability to cool higher power-densities than air cooling. Due to this, retrofitting Data Center servers initially designed for air-cooling for immersion cooling is of interest. A common area of improvement is in optimizing the air-cooled component heat sinks for the fluid and thermal properties of liquid cooling dielectric fluids. Current heat sink optimization methodologies for immersion cooling demonstrated within the literature rely on a server-level optimization approach. This paper proposes a server-agnostic approach to immersion cooling heat sink optimization by developing a heat sink-level CFD to generate a dataset of optimized heat sinks for a range of variable input parameters: inlet fluid temperature, power dissipation, fin thickness, and number of fins. The objective function of optimization is minimizing heat sink thermal resistance. This research demonstrates an effective modeling and optimization approach for heat sinks. The optimized heat sink designs exhibit improved cooling performance and reduced pressure drop compared to traditional heat sink designs. This study also shows the importance of considering multiple design variables in the heat sink optimization process and extends immersion heat sink optimization beyond server-dependent solutions. The proposed approach can also be extended to other cooling techniques and applications, where optimizing the design variables of heat sinks can improve cooling performance and reduce energy consumption.
Direct Write Thermoformed Additive Silver Circuits With SMDs Attachment for In-Mold Electronics
Authors: Lall Pradeep , Sarwar Md Golam , Soni Ved , Miller Scott 
Published: November 2023

Abstract
Additively printed thermoformable circuitry for In-Mold Electronics (IME) is getting tremendous research focus because of its numerous advantages: design flexibility, cost-effectiveness, weight reduction, and potential for seamless integration into structural components. This study uses a direct write printing technique to produce conductive FWR circuits using stretchable silver ink. A stretchable ink capable of thermoforming was used for circuit fabrication. Once the conductive traces were printed, SMDs were joined to the circuit using ECA. An impedance analyzer was used to examine the performance of the additively printed FWR circuit. Thermo-forming capable High Impact Polystyrene sheet and Polycarbonate substrates have been used for this study. The cross-section of the printed lines has been measured using white-light interferometry. The effect of the process parameters on the printed line resistivity has been studied. Optimized parameters from the printing process and sintering analysis are used to print FWR circuitry. The OrCAD software is used to simulate the FWR circuit. The simulated performance of the circuit is compared to the actual output of the printed thermoformed circuit. This work highlights the possibility of an additively printed FWR circuit in IME using a direct write process with thermoformable silver conductive ink and ECA.
Reparability Test of Aerosol-Jet Printed Sustainable Silver Ink Circuit
Authors: Lall Pradeep , Bimali Sabina , Miller Scott 
Published: November 2023

Abstract
The earlier generation of additive printable inks was based on volatile organic solvent carrier fluids. Increased awareness of the environmental impact of electronic waste has resulted in the emergence of environmentally friendly water-based inks with low-impact waste. The repairability of additively printed circuits can be used to reduce electronic waste and enable life extensions of deployed electronics through repair and replacement. However, the repairability potential, processes, and impact on reliability are relatively unexplored for new sustainable materials. This study consists of a thorough study of component attachment and the reparability of the components on performance and reliability. Repair procedures have been pursued on circuits printed with sustainable conductive ink on an aerosol jet printer (AJP). Adhesives are printed on the pads at the location where the component is to be attached using a direct-write technique that can print highly viscous materials such as ECA. This procedure entails attaching a component to a flexible printed circuit, measuring the output response, removing the attached component from the circuit, replacing it with a new component of the same rated value, measuring the output again, and comparing it to the prior output and the simulated output. Furthermore, the mechanical strength of the attached components is characterized in terms of shear load to failure. The force required to remove the attached component using a metal tip before and after the repair is compared for each of the passive components. Finally, a functional differentiator circuit is used to validate the findings.