bluuebunny/crossref_metadata_2025_split huggingface dataset:
On global robustness of an adversarial risk analysis solution
Authors: Yang Jinming , Joshi Chaitanya , Ruggeri Fabrizio 
Published: September 2024

AbstractAdversarial Risk Analysis (ARA) can be a more realistic and practical alternative to traditional game theoretic or decision theoretic approaches for modeling strategic decision‐making in the presence of an adversary. ARA relies on quantifying the decision‐maker's (DM's) uncertainties about the adversary's strategic thinking, choices and utilities via probability distributions to identify the optimal solution for the DM. ARA solution will be sensitive to the choices of prior distributions used for modelling the expert beliefs. Yet, to date, no mathematical results to characterize the robustness of the ARA solution to the misspecification of one or more prior distributions exist. Prior elicitation is known to be challenging. We present the very first mathematical results on the global robustness of the ARA solution. We use the distorted band class of priors and establish the conditions under which an ordering on the ARA solution can be established when modelling the first‐price sealed‐bid auctions using the nonstrategic play and level‐ thinking solution concepts. We illustrate these results using numerical examples and discuss further areas of research.
Thermal Management of SOI-Based Devices Using Holey Silicon-Based Lateral Thermoelectric Cooler
Authors: Luo Jiajian , Chen Jingjing , Venugopal Archana , Lee Jaeho 
Published: September 2024

Abstract
Despite its numerous advantages, the silicon-on-insulator (SOI) technology presents significant challenges in thermal management and exacerbates the local hotspot issue in microelectronic devices. The introduction of the buried oxide (BOX) layer hinders vertical heat dissipation, making conventional cooling solutions based on air and liquid coolers inefficient. To address this problem, we for the first time experimentally demonstrate the holey silicon-based lateral thermoelectric cooler (TEC) to provide thermal management for the SOI-based devices. By redistributing heat laterally, this lateral TEC overcomes the limitation of poor vertical heat dissipation caused by the BOX layer, meanwhile taking advantage of sustained temperature gradient from the hotspot. In our devices, vertical holey silicon fabricated by deep reactive ion etching (DRIE) is situated in the SOI device layer, acting as an efficient thermoelectric material compatible with conventional microfabrication processes. Neck size as small as 1.26 μm is created to enhance phonon boundary scattering, resulting in low in-plane thermal conductivity while retaining good electrical characteristics (i.e., electrical conductivity and Seebeck coefficient) from bulk silicon. The TEC electrodes (i.e., Peltier heater and cooler) deposited by e-beam evaporation align laterally with the holey silicon, enabling active heat removal in lateral direction. In addition to the TEC components, a coupled heating and temperature sensing system is implemented on the top surface using nickel thin-film structures with various dimensions. Two types of TEC designs are fabricated: asymmetric “S” type (3000 × 3000 μm2) for optimal temperature reduction and symmetric “R” type (2250 × 3000 μm2) for CMOS transistor-compatible design. All devices are generated in an SOI wafer with the following dimensions: device layer : oxide layer : handle layer = 25:5:500μm. Thermoelectrical measurement and the cross-checking IR thermography measurement are performed. While the majority of characterization is still working in progress, preliminary IR measurement results indicate large metal-silicon contact resistance is existed which hinders the TEC cooling. With further process control, optimal device demonstration and substantial cooling performance are expected in the future. In general, compared to the existing microscale TECs designed at a packaging level, our TEC allows for direct integration with the SOI-based architecture including power electronics, MEMS and microprocessors, which shows promise of a more compact and efficient cooling system for SOI-based devices.
Study of Liquid Breakup Process in Solid Fuel Booster Rocket Chamber
Authors: Amano Ryo S. 
Published: September 2024

Abstract
This paper presents a solid fuel booster rocket, both experimental and simulation studies of Al2O3 molten flow. The propulsion of aluminum composite fuel in booster rocket chambers causes severe conditions, such as high temperature and pressure, thus resulting in accumulation into molten droplets. These particles impinge on the walls in the propulsion chamber; thus, particle size and droplet distribution are the major parameters affecting erosive behavior. In this study, we investigated the phenomenon of the breakups in the relationship between gas velocity and molten particle size. The high-temperature, high-speed gas discharged from the solid fuel booster rocket has a large erosion damage on the nozzle, especially the alumina (Al2O3) particles in the gas, playing a major role in the erosion of the nozzle material. The erosion phenomenon is a serious problem since it negatively affects ballistic performance. It was discovered that the number of droplets increases by increasing gas speed in the inlet section. In the throat section of the combustion chamber, regardless of the gas speed, the average droplet size increases due to more breakup phenomena because gas velocity speeds up as the gas passes through the nozzle. However, the average droplet size decreases in the throat section by increasing gas velocity due to flow convection. The number of droplets increases by increasing gas velocity in the throat section. In the exit section of the channel, the average droplet size decreases and increases due to the flow convection.
Effect of Blowing Ratio on the Film Cooling Effectiveness on a Flat Plate With Various Blockage Ratios
Authors: Aly Omar Deyab , Wright Lesley M. , Hassan Ibrahim 
Published: September 2024

Abstract
Effusion cooling has emerged as an advanced cooling technique for applications that function at high temperatures, especially in gas turbines. Although this technology has shown higher cooling effectiveness compared to traditional cooling schemes, it is not yet considered a sustainable application for turbine stators and rotors due to manufacturing and structural challenges. The emergence of 3D printing techniques, especially additive manufacturing, is making significant strides in this direction. One such modification is the use of partition walls, barriers that are placed between the cooling holes, which were proposed to enhance the mechanical strength of the cooled components. This study aims to identify the effect of blowing ratio on the film cooling effectiveness over partitioned walls with various blockage ratios.
To understand this effect, flat plates with full effusion or partial effusion were additively manufactured. For the partial effusion configurations, blockage ratios of 20%, 40%, and 60% were studied. In a flat plate wind tunnel, the mainstream velocity was maintained at 21.6 m/s, and tests were conducted on all plates based on coolant blowing ratios of 0.1, 0.25, and 0.7 at a fixed density ratio (DR = 1.0). Pressure-sensitive paint (PSP) was used to measure the film cooling effectiveness on each plate. The results showed that raising the blowing ratio increased the coolant flow and cooling effectiveness. However, there was a practical limit to that increase since high blowing ratios resulted in significant coolant detachment, pressure decreases and flow instability. That practical limit for the baseline flat plate was at a blowing ratio of 0.25. At low blockage ratios, the cooling effectiveness varied minimally. The reduction became more significant at blockage ratios of 40%, especially for low blowing ratios, until reaching its minimum at a blockage ratio of 60%.
Effectiveness of Multi Baffles With Trefoils on the Performance of Shell and Tube Heat Exchanger
Authors: Ali Farhad , Amin Khan Tariq , Ahmad Qureshi Zahid , Muzafar Muhammad , Li Wei 
Published: September 2024

Abstract
The design and analysis of shell and tube heat exchangers are essential for efficient heat transfer in various industrial applications. This study focuses on investigating the performance of a shell and tube heat exchanger using multi-baffles with four different trefoil geometries, i.e., rectangular, square, triangular and hexagonal shapes. The objective of this research is to optimize the heat transfer efficiency by examining the effects of these multi-baffle geometries on the performance of the heat exchanger. Computational fluid dynamics (CFD) simulations and theoretical calculations are employed to evaluate the thermal performance of each geometry. CFD simulations are conducted to analyze the flow patterns, pressure drop, and heat transfer characteristics for each geometry. The effectiveness of the heat exchanger and the overall heat transfer coefficient are calculated to compare the performance of different configurations. The results obtained from the simulations and calculations provide valuable insights into the influence of different trefoiled baffle geometries on the heat exchanger’s performance. The findings indicate that each geometry has its unique impact on the heat transfer rate, pressure drop, and overall efficiency of the heat exchanger. The trefoil baffles exhibit improved heat transfer performance with hexagonal trefoil results in higher heat transfer while triangular baffles result in lower pressure drops. This research enhances our understanding of the relationship between multi-baffle geometries on the performance of shell and tube heat exchangers. The findings can be utilized to optimize the design and selection of baffle configurations based on specific industrial requirements, aiming for improved heat transfer efficiency and reduced energy consumption. Future research can explore additional multi-baffle geometries and investigate the effects of other operating parameters on heat exchanger performance to further enhance its design and performance.
Generation of Controlled Single Bubbles for Phenomenological Study of Nucleate Boiling Using a Dual-Lens Laser Spot Heating Approach
Authors: Subhani Salma , Fuentes Jesus , Melendez Karen , Lee Eileen , Quintero Michael , Dhillon Navdeep Singh 
Published: September 2024

Abstract
Nucleate boiling, despite its broad applications, remains poorly understood in several aspects. We aim to enhance the boiling performance parameters through a novel laser-based controlled bubble generation technique to enable groundbreaking phenomenological studies of the boiling process. The lab’s specialized boiling chamber and the continuous iterations regarding its surrounding set up, address practical challenges. Recent enhancements, like implementing a glass window to the experimental dual-lens set up, contribute to advancing our understanding and application of controlled bubble generation in boiling processes.
A Reproducible Molecular Dynamics Approach to Investigate the Thermal Conductivity of Al2O3 Mono Nanofluid
Authors: Smrity Araf Mim Ahmed , Yin Peng 
Published: September 2024

Abstract
Water-based Al2O3 mono nanofluid (MNF) is considered as a potential thermo-fluid for advanced cooling systems and energy storage due to its hydrophilic nature and enhanced dispersion stability. The reproducible molecular level exploration is imperative for the widespread practical applications of Al2O3 MNF. The research objective of this study is to develop a reproducible molecular dynamics (MD) simulation approach to investigate the thermal conductivity of Al2O3 MNF as a function of weight concentration (wt%) and temperature. The MD simulation framework was developed by Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) simulation tool considering Al2O3 nanoparticles wt% of 0.1, 0.5, and 1, and temperature range from 30°C to 100°C. Critical aspects including system initialization, interatomic potentials, and equilibration processes are discussed in detail in this study to ensure reproducible framework for both novice and adept researchers. The results indicated that as the wt% of nanoparticles in the Al2O3 MNF increased, there was a corresponding enhancement in thermal conductivity, with optimal performance observed at 1 wt% and 100°C. The simulation approach and results were validated by comparing with the experimental data in existing literature, which showed a difference of 3% relative to the experimental data. Future studies are planned to develop reproducible MD simulation framework to investigate factors influencing the stability of nanofluids.
Analytical Study of the Thermal Performance for an Embedded Microfluidic Cooling System
Authors: Wilhite Jarred , Kharangate Chirag 
Published: September 2024

Abstract
A compact, actively cooled heat dissipation solution has been designed and developed to adequately address the issue of increased heat generated within compact electronic devices and systems. High power density applications such as modular power converters can benefit from implementing this newly designed microfluidic cooling system, which consists of a 3-D manifold architecture and a finned microchannel array. Embedded cooling allows the manifold-microchannel (MMC) to be directly integrated into silicon carbide (SiC) based electronics, providing a more efficient thermal management system with significant mass and volume savings compared to conventional cooling strategies. This study investigates the feasibility of utilizing an MMC sample fabricated in SiC to meet chip-level heat dissipation targets of 100 W/cm2. The thermalfluidic performance was analyzed for different MMC configurations to obtain various measurements such as pressure and temperature for single-phase working fluids (i.e., water, low-GWP refrigerants, etc.). Analytical results produced from a reduced-order model show that the flow rate and the microchannel height greatly impact the performance of the MMC. Increasing the microchannel height from 200 to 300 μm provides thermal resistance of less than 0.3 K/W and pressure drop of less than 2 kPa across the system for certain working fluids.
Exploration of the Effects of Nanoscale Surface Morphology Variations on Onset of Bubble Nucleation in Water Droplets Impinging and Boiling on Nanostructured Surfaces
Authors: Silva Anisa D. , Carey Van P. 
Published: September 2024

Abstract
Nanostructured hydrophilic surfaces can enhance boiling processes due to the liquid wicking effect of the small surface structures, but consistently uniform nanoscale interstitial spaces would provide very few heterogeneous nucleation sites, which would require high superheat to activate in, for example, liquid water. Experiments indicate that surfaces of this type initiate onset of nucleate boiling at relatively low superheat levels, implying that larger-than-average interstitial spaces exist, apparently as a consequence of larger micron-scale variations of the surface structure or surface chemistry (wetting) resulting from the fabrication process. The investigation summarized here explores the potential correlation between nanostructured surface morphology variations and onset of nucleation. A zinc oxide nanostructured coating was fabricated on a copper substrate for experiments and analysis in this study. The coated surface was subjected to water droplet deposition tests to evaluate wicking and contact angle, followed by vaporization tests at varying surface superheat levels, and extensive electron microscopy imaging of the surface. The results of the vaporization experiments determined the variation of mean heat flux to the droplet as a function of superheat, and high-speed videos documented the superheat at which onset of nucleate boiling (ONB) occurs and variation of nucleation site density with superheat. Image analysis of the electron microscopy images were used to assess the variability of pore size and surface complexity (entropy) over the surface. By determining macroscope bubble nucleation and boiling performance from measured data and high-speed video records for these surfaces, and simultaneously analyzing the morphology of that surface at the micro/nano scale, our data demonstrates the correlation between surface morphology variations and ONB and nucleate boiling active site density. Specifically, our results indicate that increased irregularities in the surface morphology correspond to enhanced probability of nucleation onset and an increase in active nucleation site density as superheat increases. Our data indicates the range of irregularity number density values (number per square millimeter) and the imperfection features that give rise to consistent low superheat ONB (∼ 15°C), leads to a robust increase in active site density during nucleate boiling as super heat increases. This information can help guide development of enhanced boiling surfaces by providing insight into the frequency of nanosurface morphology variations, per square millimeter, that enhance nucleation onset while also providing enhanced wicking and low contact angle over most of the surface. The implication of these results for design of different types of enhanced boiling surfaces is also discussed.
Analysis of Building Cooling System’s Load Under the Effect of the Phase Change Material-Based Thermal Energy Storage System
Authors: McKenna Stuart , Clark Peyton , Omiddezyani Soheil , Shah Krishna , Samadi Forooza 
Published: September 2024

Abstract
Phase change material (PCM) based cooling load reduction analysis commonly incorporates thermal energy storage (TES) on the building interior. Such systems are constrained by the limited overlap in suitable exterior temperatures for TES recharging with acceptable indoor comfort temperatures. In the current paper, this constraint is removed by moving the TES to the exterior and optimizing the TES system design for a certain climate, including PCM size and operating temperature window. The goal of this optimization will be reducing the ambient air temperature before the condensing heat exchanger in typical HVAC equipment for cooling applications to improve its coefficient of performance (COP) and minimize the annual cost. Utilization of organic fatty acid mixtures as the PCM will allow for selecting a solidification temperature appropriate to a given climate. This analysis attempts to minimize the annual cost of cooling structures by appropriately sizing TES systems with suitable eutectic or near-eutectic mixtures of fatty acids for a given climate. For a targeted climate, by analyzing the solidification temperature of a fatty acid mixture and the temperature at which the TES cools the ambient air, energy usage is reduced at times of peak cooling demands to optimize the efficiency of the combined TES and HVAC system and maximize energy cost savings.
Numerical Heat Transfer Analysis of NACA Pin-Fin Thickness
Authors: Fogel Rutledge , Ekkad Srinath V. 
Published: September 2024

Abstract
Energy efficiency and performance are priorities for modern gas turbine engines. The increasing demand for energy efficiency and higher performance has driven the development of cooling technologies within gas turbine engines. This new demand has increased the constraints for performance on cooling technology within the hot section of gas-turbine engines. Pin-fin arrays are an important component of cooling technology within gas turbine blades. NACA airfoil-shaped pin-fins have been shown to have a high thermal performance balancing the need for heat transfer performance and low-pressure ratios. To find an efficient pin-fin shape to increase the heat transfer characteristics and lower flow resistance, several rectangular channels with NACA airfoil pin-fin shapes in a staggered array were numerically tested and compared using ANSYS Fluent 22.2. The NACA pin-fin shape was tested with varying diameter. Channel Reynolds number will be varied from 10000 to 15000, and 20000. The spanwise spacing ratio (S/D) was maintained at a constant value of 3. The initial streamwise spacing (X/D) was also set to a value of 4 while the streamwise spacing (X/Lpin) was set to 1.333. The width and length of the rectangular channel were also normalized with the diameter and total length of the NACA pin-fin. The width of the channel (W/D) varies with the thickness (D) of the NACA pin-fin. The length of the channel (Ltest/Ltotal) also varies with the total length of the pin-fin (Ltotal). Results show significant improvement with larger diameter airfoil shapes for heat transfer but also increased overall pressure drop in the channel.
Improvement of a Low-Cost Apparatus for Measuring Thermal Conductivities of Solids at Steady-State
Authors: Bunt Brandon , Wright Kamau , Davis Benjamin 
Published: September 2024

Abstract
The present work improves upon an instrumented rig developed at relatively low cost as part of a previously published study [1] to measure thermal conductivity of metal samples like brass and aluminum. The materials tested as part of the present work are copper, aluminum, brass, alumina ceramic, and stainless steel. Literature k-values for these materials range two orders of magnitude (from 398 Wm−1K−1 for copper down to 14.9 Wm−1K−1 for stainless). The linear heat conduction module (LHCM) used in this study approximates one dimensional heat transfer through a stack of cylindrical metals of known thermal conductivities having a sample of unknown conductivity placed in between them at the midsection of the stack. By maintaining an isothermal boundary layer on the bottom of the LHCM and applying a constant heat flux through an electrical resistance heater at the top, a temperature difference is maintained and measured along the sample at steady state allowing for the use of Fourier’s Law to estimate the sample’s thermal conductivity. The present LHCM addresses issues with the initial rig such as large radial heat losses, fluctuations in boundary conditions, and large uncertainties in measurements which prevented determination of thermal conductivities outside of a narrow range.
Measuring Thermal Conductivity of Mycelium-Based Thermal Insulation Materials Produced With Locally Available Organic Waste Products As Substrate
Authors: Bunt Brandon , Wright Kamau , Davis Benjamin 
Published: September 2024

Abstract
Current steady-state methods have long test-times than transient methods and are often not suitable for low-k materials due to heat applied through the sample material being lost to the surrounding environment instead of traveling through the sample. Here, a low-cost design seeks to demonstrate measurement of the thermal conductivity of mycomaterial samples accurate within 10% using steady-state methods. This design is different from but inspired by the “hot-wire” and conductive disks approaches, and closely resembles a coaxial cylinders approach used for thermal properties assessment of molten salts. [1]