bluuebunny/crossref_metadata_2025 huggingface dataset:
The Difference in Blue Water Usage of Meals Prepared at Home Versus Meals Prepared Away From Home
Authors: Sices Schuyler , Wemhoff Aaron P.
Published: September 2023

The global trend of increasing consumption of food prepared away from home (FAFH) versus food prepared at home (FAH) can have environmental consequences such as blue water footprint. This study therefore estimates the difference in blue water usage of FAFH versus FAH. Blue water footprints of individual food items and consumer survey data were combined to obtain overall values for FAFH and FAH consumption. The data suggest that FAFH consumes approximately 258 L per kilogram of food, which is approximately 15% higher than FAH. The difference in water footprint is largely due to an increased consumption protein-based meals in FAFH compared to FAH. However, the gap in water footprint is mitigated by the increased consumption of high water-consuming snacks at home such as nuts and dried fruits, as well as meal ingredients like processed oils. The calculations suggest a much higher water footprint per kcal and per USD in FAH versus FAFH. Finally, nuts and dried fruit are found to have the highest specific water footprint despite a relatively low carbon footprint.
Power Generation Maximization Control Framework for Ocean Current Turbine Farms
Authors: Ondes Ertugrul Baris , Sultan Cornel , VanZwieten James H.
Published: September 2023

In this work, we propose a control framework for farms consisting of ocean current turbines (OCT). The ocean current turbine systems used in this farm are tethered to the ground of the ocean, and their depth can be adjusted online based on the maximum ocean current power available. To maximize the average power generated by the farm, the ocean current turbine wake interactions must be taken into account, and also each turbine in the farm should achieve these changes in the position reference with minimum control energy. Considering additional limitations such as keeping the tethering cables away from each other and avoiding collisions between the turbines, an advanced optimization framework is developed to achieve the maximum power generation in a specified region. Tracking of the reference trajectories by the ocean current turbine systems is achieved by model predictive control (MPC). A case study is presented to highlight the significant estimated improvement in the average energy generated by the farm using the proposed framework and control methodology.
Electrification and Decarbonization Using Heat Recovery Heat Pump Technology for Building Space and Water Heating
Authors: Yu Byeongho , Kim Dongsu , Koh Jaeyoon , Kim Jinman , Cho Heejin
Published: September 2023

Buildings are one of the major contributors to global greenhouse gas emissions. Decarbonizing building sectors has greatly been emphasized globally. For example, New York state has an aggressive roadmap to decarbonize the building sectors by 2050. To achieve this, electrification of space heating and water heating systems is critical, and it requires energy-efficient and feasible solutions rather than electric coil heating. This study proposes a heat recovery-enabled heat pump technology (i.e., variable refrigerant flow with heat recovery (VRF-HR)) for space heating and domestic water heating and presents a feasibility study of the proposed technology to evaluate decarbonization performance. A computational model is developed to simulate the energy performance of the proposed technology. The model uses a refrigerant circuit box to control refrigerant flows between indoor and heat recovery units for simultaneous space cooling, space heating, and/or hot water generation. A case study for apartment and hotel buildings located in New York City is conducted to demonstrate the feasibility of the proposed technology for decarbonization compared to a conventional system. Building energy simulations are carried out using a whole building energy modeling tool, EnergyPlus. Based on hourly simulation results, the post-process calculation is performed to examine the energy-saving and decarbonization potential by comparing with results from a conventional natural gas-based space and domestic water heating system. Results indicate that the proposed VRF-HR system can effectively achieve building electrification and decarbonization with lowered energy consumption (i.e., about 20% of annual cooling/heating energy savings and 80% of domestic hot water energy savings). Results also show that heat recovery technologies are a remarkable addition to enable electrification and decarbonization effectively.
Numerical Investigation of Thermochemical Energy Extraction in a Moving Packed Bed Oxidation Reactor-Heat Exchanger
Authors: Mishra Ashreet , Korba David , Li Like
Published: September 2023

Moving packed bed heat exchangers (MPBHXs) are becoming an increasingly attractive option for particle-to-sCO2 heat exchangers (HXs) and integrating thermochemical energy storage based on metal oxide redox cycles with concentrated solar power (CSP) systems can provide significant advantages compared to sensible heat storage systems, such as higher energy storage density, higher working fluid (WF) temperature and potentially lower system costs. This work focuses on computational modeling of a shell-and-plate moving bed oxidation reactor-heat exchanger design that utilizes the exothermic oxidation of metal oxide particles under air flow to enhance thermal transport to sCO2 via both sensible and thermochemical heat exchange. A 2D volume-averaged continuum model is developed by coupling the counter-current air-particle flow, interphase heat transfer, thermochemical oxidation reaction, and species transport in the particle channel with sCO2 flow in the WF channel. The counter-flow particle-sCO2 sensible heat exchanger model is verified with previous numerical models in the literature, whereas the transport-reaction model within the particle channel is adopted from previous literature. For the baseline cases with similar geometry, operating parameters, and particle sizes, the total heat transfer for the TCES based HX was 16.71 kW compared to 4.62 kW for sensible only HX. The maximum extent of oxidation at the particle channel outlet was ∼75%, and the sCO2 outlet temperature was 692°C for reactive particles compared to 595°C for inert particles. A parametric study was also conducted to determine the effects of sCO2 and air flow rates on the temperature, extent of reaction, O2 absorption, and total heat transfer of the HXs.
Demonstration of Multiyear Solar Thermochemical Energy Storage via the Cobalt Oxide Cycle
Authors: Bassett Katherine , Silcox Rachel , Smith Ben , Schmit Brian , Will Jeffrey D. , Venstrom Luke J. , Krenzke Peter T.
Published: September 2023

We present a proof of concept demonstration of solar thermochemical energy storage on a multiple year time scale. We designed and fabricated a 4-kW solar rotary drum reactor to carry out the solar-driven charging step of solar thermochemical storage via metal oxide reduction-oxidation cycles. During the summer of 2019, the solar reactor was operated in the Valparaiso University solar furnace to effect the reduction of sub-millimeter cobalt oxide particles in air at approximately 1000°C. A particle collection system cooled the reduced particles rapidly enough to maintain conversions of 84–94% for feed rates of 2.9–60.8 g min−1. The solar to chemical storage efficiency, defined as the enthalpy of the reduction reaction at 1000°C divided by the solar energy input, reached 20% for an input solar flux of 1400 kW m−2 and a cobalt oxide feed rate of 60.8 g min−1. Samples of the reduced cobalt oxide particles were stored in vials in air at room temperature for more than three years. The stored solar energy was released by reoxidizing samples in air in a benchtop reactor. Measurements of the oxygen uptake by the reduced metal oxide confirm its promise as a medium to store and dispatch solar energy over long durations.
Leveraging HVAC Set Point Changes for Operational Energy Performance Efficiency and Flexibility in Commercial Buildings: Experiments in a Moist Climate Zone
Authors: Grekin Rebecca , de Chalendar Jacques
Published: September 2023

In this work, real-world demand flexibility experiments for Heating, Ventilation, and Air Conditioning (HVAC) systems were conducted over the summer of 2022 in sections of a commercial building at a corporate campus in New Jersey (US Climate Zone 5A, Moist Cold). These experiments measured the decrease in cooling load observed associated with an increase in the temperature set point for the air discharged from eight central air handling units (AHU) serving approximately 17,500 square meters. It was found that using outside air enthalpies for estimating cooling loads in climates that have higher humidity is more accurate than using the mean daily temperatures, the parameter most used in the literature. For the median observed outside air enthalpy of 60 kJ/kg, it was found that temperature set point increases of 2°F (1.11°C) for the AHU discharge air temperature decreased expected cooling load by 3.5–11.9% per AHU. These results highlight the importance of considering outside air humidity in addition to temperature in flexibility models. These experiments also show that it is possible to implement load reduction techniques in buildings with limited controls, which reinforces the large potential for electricity and emissions savings from leveraging these opportunities across the US.
Investigation on a Double-Pass Tubular Absorber for Application in Solar Towers
Authors: Ebadi Hossein , Cammi Antonio , Savoldi Laura
Published: September 2023

The present study combines the concept of double-pass flows with high-temperature solar receivers, introducing a novel design to reduce heat losses and increase performance. A tubular absorber from the billboard solar tower systems was used to develop the new double-pass (DP) design, working with air as the heat transfer fluid. To assess the effectiveness of such a system, a numerical study was performed using CFD analysis with Star CCM+ commercial software. Several simulations were made based on the thermal models, validated with real data obtained from a solar furnace tested during an experimental campaign in June 2022. The thermo-hydraulic characteristics were analyzed for various solar peak fluxes (50, 100, and 200 kW/m2) and air mass flow rates (30, 40, 50 L/min) to provide a comprehensive comparison between the single pass (SP) and DP absorbers. The computed numerical results suggested that using the DP design instead of SP absorbers under all the test conditions, the average energy and exergy efficiency enhancement are 35% and 55%, respectively, while the pressure drop increases with an average of 62%. As a result, the DP design can be used as an alternative for future solar tower designs, bringing higher heat removal efficiency in air-based solar systems.
Time-Dependent Solution of Unsteady Flow Equations for Nanoscale Heat and Mass Transfer, Advanced Fluidics, and High Energy Blast Propagations
Authors: Sinha Ramlala P.
Published: September 2023

A new innovative stable time-dependent compressible flow solution over the order of nanoseconds is provided here for wide-ranging critically important challenging applications. Specifically, a solution of the highly complex unsteady high speed oscillating compressible flow field inside a cylindrical tube, closed at one end with a piston oscillating at very high resonant frequency at the other end, has been obtained numerically, assuming one dimensional, viscous, and heat conducting flow, by solving the appropriate fluid dynamic and energy equations. An iterative implicit finite difference scheme is employed to obtain the solution. The scheme permits arbitrary boundary conditions at the piston and the end wall and allows assumptions for transport properties. In successfully predicting the time dependent results/data, an innovative simple but stable solution of unsteady fluid dynamic and energy equations is provided here for wide ranging research, design, development, analysis, and industrial applications in solving a variety of complex fluid flow heat transfer problems. The method is directly applicable to pulsed or pulsating flow and wave motion thermal energy transport, fluid-structure interaction heat transfer enhancement, nanoscale heat and mass transfer, diverse range of advanced fluidics, and fluidic pyrotechnic initiation devices. It can further be easily extended to cover muzzle blasts and high energy nuclear explosion blast wave propagations in one dimensional and/or radial spherical coordinates with or without including energy generation / addition terms. No other solution exists for such applications.
Flow and Heat Transfer Characteristics of Aerothermodynamic Loading on a Double Cone at Mach 12
Authors: Gamertsfelder Jacob , Redding Jeremy , Bravo Luis , Khare Prashant
Published: September 2023

Although a significant body of research exists on shock-wave shear layer interactions (SWSLI), the scientific literature is lean with respect to the physics underlying SWSLI at extreme Mach number regimes. It is well known that small perturbations can lead to significant fluid dynamic changes (e.g., transition and associated heat transfer characteristics) at high Mach numbers, especially when the flow is in thermal and chemical non-equilibrium. While experiments have investigated the physics of flow over compression ramps, the physio-thermo-chemical processes remain elusive at high enthalpy condition. The dynamics are further complicated in the presence of non-smooth surface (due to the impact of debris, uncertainties in manufacturing processes, etc.) that drastically enhances the near-wall interactions. This is of great importance to accurately predict the aerothermal performance and trajectory of high-speed vehicles operating with realistic material surfaces (e.g., roughness elements, cavities, or protrusions). To address this, this research aims to investigate the influence of thermochemical non-equilibrium flow over a smooth double cone, and the influence of concave cavity on a double cone on the resulting post-shock non-equilibrium high-speed aerodynamic flow, and the associated SWSLI and heat transfer characteristics. In the present work, the massively parallel computational fluid dynamic solver, Eilmer, is utilized to simulate compressible high-speed fluid dynamics and near-body flow physics. Eilmer is a structured/unstructured grid flow solver based on finite-volume discretization of the time-accurate compressible Navier-Stokes equations with validated turbulence models, finite-rate internal energy excitation, and chemical kinetics. The work first targets a validation case study conducted based on measurements at the CUBRC facility that investigated the high-speed flow over a 25/55-degree double cone at a Mach number of 11.9 on an idealized smooth surface. Next, an in-depth overview of the thermochemical non-equilibrium flow physics is presented for the 2D axisymmetric 25/55-degree double cone. From there, a series of 2D axisymmetric double cone computations are conducted with a semi-circular cavity on the 55-degree surface region with a radius ranging from L/R (length of the ramp/cavity radius) of 100 to 33. The evolution of near-surface phenomena of interest, such as shear layer mixing and heat transfer are quantified showing increased intensities due to the presence of the cavity. The results from this study provide much-needed insights into the underpinning behavior governing SWSLI in the presence of non-ideal surfaces, and the effect of thermochemical non-equilibrium in higher Mach number flows.
Hydrogen-Fueled Regenerative Burners in a Reheating Furnace
Authors: Karambelkar Anurag , Uzor Chukwunedum , Walla Nicholas , Silaen Armin , Johnson Kurt , Zhou Chenn
Published: September 2023

In steel production, reheat furnaces are used to heat steel slabs to prepare them for further processing. However, the traditional use of natural gas burners as the primary heat source in these furnaces results in significant carbon dioxide emissions. As a result, the steel industry has been focusing on decarburization efforts, with research aimed at identifying viable alternatives to natural gas, such as hydrogen. Furthermore, the use of regenerative burners in reheat furnaces is being explored as a means of improving heating efficiency and reducing fuel usage. This system employs a thermal reservoir and alternating burner activity to preheat inactive burners and quickly reach combustion temperatures. This preheating increases the efficiency of the system as combustion temperatures are reached more-quickly. This increased efficiency reduces fuel usage and can improve the heat output of the furnace. The present study compares the operation of traditional and regenerative burners with methane and hydrogen as fuel. It was observed that the inclusion of regenerative burners in the system provide a more uniform temperature distribution and a longer flame compared to the traditional burners. They also showed an increase of more than 120°C in peak temperatures near the slab despite having lower max flame temperature than the traditional case. The use of regenerative burners in a hydrogen fueled furnace was shown to increase the production efficiency by 14.14% compared to traditional burner methane fueled furnace. Additionally, the use of hydrogen as a fuel in place of the natural gas results in carbon-free emissions, thus reducing the environmental impact of the process and advancing decarburization efforts.
Thermal and Flow Characteristics in a Tube with Helical Ridges
Authors: Chen Tailian
Published: September 2023

Use of tubes with helical ridges to make shell/tube heat exchangers has been an industry practice for many decades. However, understanding of thermal and flow characteristics with helical ridges is far from being sufficient. In this paper, thermal and flow characteristics of single-phase water flow in a cylindrical tube with spiral helical ridges is investigated to understand the enhancement in heat transfer and the associated penalty in the increased pressure drop. The experiments were conducted in the range of Reynolds number 3,700 to 75,000 and Prandtl number 3.8 to 10.0. The measurements show that thermal and flow characteristics are different from those reported in the literature for flow in commercial pipes with roughness. An analysis of friction factors measured in this work delineates the flow characteristics in a tube with helical ridges, which would help further explore the underlying physics. A comparison against the Moody chart and Churchill correlation indicates that the transition region covers a wider range of Reynolds number and extends into a much larger Reynolds number. It is postulated that the much wider transition region is attributed to helical ridges providing a channeling effect for the fluid flowing on the surface, which is absent for flow on a general rough surface. The heat transfer enhancements and the penalty of pressure drop measured in this work are further quantified and compared with suggested correlations available in the literature.
Quadrature Point Selection in the Full-Spectrum K-Distribution Method for Nongray Radiation in Combustion Gases
Authors: Jajal Nehal , Mazumder Sandip
Published: September 2023

Radiation is the dominant mode of heat transfer in combustion environments. Combustion gases, such as carbon dioxide and water vapor, have oscillatory spectral properties. Solving the Radiative Transfer Equation (RTE) is challenging in such scenarios and requires a nongray model. The Full-Spectrum k-distribution (FSK) model is a popular state-of-the-art model that offers high accuracy while requiring the RTE to be solved for only a few quadrature points in reordered spectral (or g) space. The selection of optimal quadrature points has been investigated in the literature, broadly suggesting that 8 to 10-point schemes, with more points for larger g-values, work best. In this study, a new split scheme is tested for quadrature point distributions wherein the g-space is first split into two zones prior selecting quadrature points for each zone. The split scheme is tested for one-dimensional gas slabs with uniform properties of carbon dioxide, water vapor and a mixture for different temperatures. Slab thicknesses are varied to vary the optical thicknesses. Errors for radiative heat source and radiative wall flux are computed against benchmark line-by-line (LBL) solutions. Results are compared with existing quadrature schemes. Overall, the split scheme resulted in an improvement in accuracy compared to existing quadrature schemes more consistently across different length scales for the same number of quadrature points.
Integrated Greenhouse for Food and Water Production
Authors: Abedi Mahyar , Tan Xu , Klausner James , Benard Andre
Published: September 2023

Large greenhouses are increasingly used for modern farming, occupying vast areas, and consuming considerable amounts of energy to maintain their functionalities. In this study, the performance of an energy-efficient greenhouse comprised of a transparent solar water heater, coupled with a spectrum-shifting material, and a water desalination unit, is investigated. A transparent solar water heater is installed on the greenhouse roof and provides warm water to be used for desalination. The addition of a spectrum-shifting material to the solar water heater can enhance the efficiency of the thermal system by absorbing wavelengths near-infrared waveband (NIR) or shifting the light to a spectrum more favorable to specific crop growth. Moreover, a desalination unit allows the treatment of a wide range of contaminated or saline waters to satisfy the crops’ potable water needs. The investigated desalination system utilizes direct-contact evaporation and condensation through a packed-bed material. Based on the simulation results for Phoenix Arizona, the transparent solar water heater is able to increase the water temperature by up to 25°C, while allowing sufficient light to pass through to maintain plant growth. Moreover, the implementation of a transparent solar water heater decreases the cooling and heating loads. The investigated greenhouse design is able to sustain hydroponic lettuce cultivation, for example, throughout the year, and satisfy the potable water requirements, thus producing up to 400 kg of fresh lettuce per month.
Numerical Simulation of Particle Evolution in Spray Drying Using Droplet Drying Kinetics
Authors: Bhattacharjee Anurag , Gnanaskandan Aswin
Published: September 2023

Spray drying is a method for producing dry powder particles (e.g., instant coffee, milk, starch, cheese, bio-therapeutics, etc.) by atomizing a slurry and rapidly drying it using a hot gas in a drying chamber. Understanding the evolution of particle formation in a spray dryer is important as it directly influences the final product quality. Experiments inside a spray dryer are often not able to shed light on the physical processes governing the particle formation at the scale of an individual particle. Hence, we are developing a numerical method that uses complex mass and heat transfer equations to account for the change in properties of a single droplet based on advanced droplet drying kinetics. Such a model can be later incorporated into full-scale drying chamber simulations, where CFD modeling of the drying gas flow can be coupled to these single droplet models. The drying model is divided into two stages of drying with distinct equations accounting for heat and mass transfer during these stages. The first stage consists of droplet shrinkage with loss of moisture and diffusion of dissolved or suspended solid particles inside the droplet. At the end of the first stage, the volume fraction of the dissolved or suspended solid content on the droplet surface reaches a critical saturation level at which point a porous crust is formed indicating the start of the second stage. Heat and mass transfer from the droplet is assumed to occur through the porous crust. The model is validated using single droplet drying experiments from the literature showing reasonable agreement with the experimental data for temperature and mass evolution. The model is then used to conduct parametric studies to understand the role of the different factors that influence the final droplet morphology. The results show that the droplet mass and temperature evolution are affected greatly by the drying gas velocity and temperature, while the relative humidity of the drying gas has only a moderate effect. The model can be applied to ascertain the optimal external conditions needed to obtain particular particle characteristics.
Transient Thermal Spreading From a Circular Heat Source in Polygonal Flux Channels
Authors: Goudarzi Sahar , Steigerwalt Lam Lisa , Muzychka Yuri , F. Naterer Greg
Published: September 2023

Thermal spreading or constriction resistance plays an important role in thermal engineering problems. A numerical simulation is developed for transient constriction resistance considering various semi-infinite flux channel geometries, including circle on circle, circle on triangle, circle on square, circle on pentagon, and circle on hexagon. In this work, an isothermal circular heat source supplies heat in these polygonal flux channels. In this context, a finite volume method is considered to study the transient constriction resistance in mentioned geometries. After validating the steady-state mode for constant heat flux condition, the work is extended to study the transient heat conduction with constant temperature boundary condition. Observations of these various geometries clarify that similar results are produced for the non-dimensionalized constriction resistance and time. The appropriate characteristic length for this non-dimensionalization is the square root of the source area. Simple models are developed for predicting the transient spreading resistance for isothermal heat sources.
Estimation of Heat Flux From Gases Released During Thermal Runaway of Lithium-Ion Batteries
Authors: Qatramez Ala' E. , Kurzawski Andrew , Hewson John , Foti Daniel , Headley Alexander J.
Published: September 2023

A jet is formed from venting gases of lithium-ion batteries during thermal runaway. Heat fluxes to surrounding surfaces from vented gases are calculated with simulations of an impinging jet in a narrow gap. Heat transfer correlations for the impinging jet are used as a point of reference. Three cases of different gap sizes and jet velocities are investigated and safety hazards are assessed. Local and global safety hazard issues are addressed based on average heat flux, average temperature, and average temperature rise in a cell. The Results show that about 40% to about 70% of venting gases energy can leave the module gap where it can be transferred to other modules or causes combustion at the end of the gap if suitable conditions are satisfied. This work shows that multiple vents are needed to increase the temperatures of the other modules’ cells to go into thermal runaway. This work is a preliminary assessment for future analysis that will consider heat transfer to the adjacent modules from multiple venting events.
Study on the Effects of Temperature Distribution and Liquid Volume on the Growth of a Deuterium-Deuterium Ice in the Cryogenic Target
Authors: Wu Kewei , Yao Yina , Zhang Hui , Zheng Lili
Published: September 2023

Inertial confinement fusion (ICF) is one of the main ways to achieve controlled nuclear fusion. ICF experiments use high peak-power laser systems to compress the capsule with a layer of solid hydrogen inside, making the ice layer highly compressed so as to initiate ignition. To achieve an ignition with a cryogenic target, the fuel ice layer (DT or D2) in the target needs to be highly symmetrical, uniform and smooth. For a better control of the ice preparation process, there is a need to develop a deep understanding on the mechanism of the crystal growth process. Based on VOF model, Solidification/Melting model and the Evaporation/Condensation model, we establish a numerical model to simulate the coupled process of fluid flow, heat transfer, solidification and condensation of D2 fuel. Through assigning different temperature boundary and initial liquid fraction conditions, the impacts of temperature distribution and liquid volume on the crystal growth process are investigated. The results show that higher temperature gradient, bigger liquid volume and larger coefficient of heat transfer promotes the formation of radial temperature gradient in the capsule, which helps to ensure the global coverage of liquid film. Our work can help to optimize the relevant parameters in in the preparation process of D2 ice layer.
Variable Properties via Excel: Numerical and Computational Heat Transfer Methods
Authors: Abdelmessih Amanie
Published: September 2023

Most of us, engineers have, or will model or simulate project(s) or portions of projects. A couple of articles introduced computational methods using MS Excel. Three rectangular cross section conduction heat transfer computational cases using Microsoft Excel have been discussed in detail, in the first article. With the realization that circular cross sections such as cylinders, pipes, rods, etc. have unlimited applications in engineering practice, the second article addressed four computational heat transfer cases for circular cross sections using Microsoft Excel. These four circular cross section cases were modeled with two different Excel techniques and discussed. Unfortunately, both articles addressed only constant thermal properties.

Thermal properties dependent on temperature are included in all seven models introduced in this article. The first two models are rectangular with isothermal boundaries and variable properties for two different materials. The third and fourth models are for circular cross sections with isothermal boundary conditions, though they are modeled with two different methods. Model 5 is rectangular cross section with different boundary conditions, it has two versions one is approximate. Model 6 includes internal convective flow, where the heat transfer coefficient depends on variable thermal properties. Finally, Model 7 includes a heat source. The details of each model, derivation of equations and computations are discussed in this article.
Investigation of Universal Consolidated Database for Heat Transfer Coefficient in Flow Condensation and Machine Learning Modelling
Authors: Pirnstill Logan M. , Qiu Yue , Kharangate Chirag
Published: September 2023

Miniature condensers have been recognized as an effective tool for developing compact heat rejection devices. However, due to complex physical behaviors resulting from phase change, predicting necessary quantities like heat transfer coefficient has proven to be a difficult task. This study will use a database of 37 flow condensation studies for development of machine learning tools to predict two-phase heat transfer coefficient. In comparison to previous work performed by Zhou et. al. [1], this study will utilize thermodynamic data, dimensionless flow data, channel type, channel geometry, single and multichannel systems, and fluid species, as a more comprehensive means of predicting heat transfer coefficient. This study finds that in conjunction with the dimensionless quantities used in previous studies [1], the variables; mass velocity, quality, latent heat, specific volume, and hydraulic diameter are all of important significance to accurately predicting heat transfer coefficient. This study is a comprehensive Exploratory Data Analysis (EDA) as well as a machine learning based model for accurately predicting heat transfer coefficient. We find Mean Absolute Percent Error (MAPE), using simple multi-linear regression, of significantly less magnitude using our more comprehensive database as compared to previous works. Machine Learning methods also show a reduction in MAPE as compared to previous studies, as well as compared to previous semi-empirical correlations for heat transfer coefficient.
In-Situ Bottom-Up Temperature Measurements for Laser Powder Bed Fusion Metal Additive Manufacturing
Authors: Pratt Mason , Ameel Tim , Rao Sameer
Published: September 2023

Spatially resolved temperature measurements and understanding the local heat-affected zone (HAZ) are of urgent importance in metal additive manufacturing (AM). Many experiments have used infrared (IR) temperature measurements at the build surface, but there is little experimental work measuring temperatures below the surface. Measurements below the top surface are vital to understand how the heating of additional build layers affects the temperature history of previously printed layers, especially in thin geometries. A thin metal plate with incident laser power can reasonably represent such thin geometries, for example, an overhang feature of an actual part undergoing laser powder bed fusion (LPBF). As a part of this work, we describe the design, construction, and calibration of an experimental setup that allows direct measurement of temperature distributions on the bottom side of a metal substrate. This is accomplished using a high-speed IR camera (2000 fps) positioned below a thin Inconel 625 substrate of known thickness (500 μm) and emissivity. The top side is irradiated with a high-power ytterbium fiber laser, while temperature distributions are measured on the bottom surface. The local temperature on the bottom side is resolved with a spatial resolution of 200 μm in the x and y directions. Local temperature distributions and HAZ dimensions are reported for single-track scans as a function of the laser power. The insights derived from this study will ultimately establish a fundamental link between laser processing parameters, local thermal history, and printed part properties.
Numerical Predictions of the Flow and Heat Transfer Characteristics in the Film Boiling Regime During Tube Quenching
Authors: Narayanan Jayachandran K. , Hylton Sonya , Kassemi Mohammad , Hartwig Jason W. , Mackey Jeffrey R. , Kharangate Chirag R.
Published: September 2023

Cryogenic fluid management plays a major role in refueling of spacecrafts while in space for NASA’s future human space exploration missions. Due to the low boiling points of cryogens, storage, transport and handling of these fluids becomes difficult and may result in inefficient operation of the space propulsion systems. For refueling applications in space, the cryogenic fluids have to be transported across different locations and hence, the transfer of cryogenic fluids through pipes become critical. The cryogenic chill-down process is characterized by different regimes of flow boiling, viz., film boiling, transition boiling and nucleate boiling. The prediction of these regimes in a single CFD framework available in the literature is challenging and the present work attempts to address this challenge by initially modeling the film boiling regime accurately and to incorporate an user-defined function for transition and nucleate boiling at a later stage. Hence, the aim of the present work is to numerically model and validate the film boiling regime of the chilldown curve for liquid nitrogen experiments available in the literature. The validations are carried out at different inlet mass fluxes to have a robust simulation methodology. A dispersed mixture model is used to predict the vapor-liquid interface dynamics with the phase change phenomena modeled using the Lee model.
Study of Inclusion Detection Using Bayesian Inference for an Application in Breast Tumors
Authors: Menegaz Gabriela L. , Araujo Cleudmar A. , Guimaraes Gilmar
Published: September 2023

Early and accurate detection of breast cancer is a critical part of the strategy to reduce morbidity and mortality associated with this common disease. This work’s main objective is to develop a non-invasive technique for early detection of breast tumors without using radiation and causing discomfort to the patient. The method should allow access to people with disabilities or low mobility. Detection of inclusions becomes possible due to definitions of damage metrics, which are statistical parameters capable of numerically representing the difference between two measurements before and after damage. The experimental technique proposes to estimate k and the central position of inclusion, b0, inserted in a phantom. The value of k estimated corresponds to the thermal property of healthy tissue. The central position of the inclusion corresponds to the position of possible tumor localization in the breast phantom. The method uses the same pair data heat flux/temperature measured at the phantom surface in different parting times. k and b0 are estimated by maximizing the likelihood function between theoretical and experimental temperature data on the phantom’s surface using times less than 350s and above 400 s, respectively. A 1D thermal model that considers heat generation is used.
Performance Comparison of Thermal Management Systems for Battery Packs Based on Numerical Simulation
Authors: Raghu Sowmya , Rajabi Roya , James Robin , Huang Kevin , Khan Jamil A.
Published: September 2023

Rechargeable lithium-ion batteries (LIBs) are being used extensively in automotive and aviation industries as we move towards sustainable, energy efficient, and affordable futuristic transportation. Due to their high-power density (up to 10,000 W/L) and energy density (up to 705 Wh/L), lithium-ion batteries are excellent candidates to be utilized as an energy source. Thermal management of the batteries are essential to maintain a safe and uniform operating temperature envelope based on different applications. Large lithium-ion battery packs face several challenges, however thermal management is critical in ensuring safety, optimum power output and prevent thermal stress induced aging effects. Although, different cooling techniques are presented in literature, it is extremely difficult to present the best choice of the technique without performing trade-off studies. This paper presents a comparative study of the cooling effectiveness of standard heat sink, Phase Change Material surrounding the batteries, and heat sink with circular, square and airfoil fins, with Phase Change Material (PCM) for efficient management of the temperatures of lithium-ion battery packs at high charging and discharging rates. A coupled thermal-electrochemical numerical simulation study is conducted to compare the 4 different types of cooling techniques to maintain the operational temperature between 15°C–50°C. A parametric study is conducted for variable power of the battery pack at high charging and discharging rates and the cooling performance enhancement through the use PCM with surface modifications in the heat sink is examined.
Generalization of spontaneous imitation from nonwords to real words
Authors: Wang Yamei , Kwon Harim
Published: September 2023

This study reports that English speakers, after shadowing English-like nonwords beginning on /p/ with extended voice onset time, spontaneously shifted their subsequent reading productions of English words converging toward the shadowing targets. The extent of the imitative changes correlated positively with the speakers' declarative memory of the nonwords, but not with the lexical frequency of the produced words. These findings provide evidence for the phoneme-level abstraction in perceptually induced phonetic drifts while they further suggest that the mechanisms underlying phonetic drifts in direct shadowing, and in subsequent productions of words differing from the shadowing targets, may not be identical.
Directional characteristics of two gamelan gongs
Authors: Bellows Samuel D. , Harwood Dallin T. , Gee Kent L. , Shepherd Micah R.
Published: September 2023

The distinctive geometry and structural characteristics of Balinese gamelan gongs lead to the instrument's unique sound and musical style. This work presents high-resolution directivity measurements of two types of gamelan gongs to quantify and better understand their acoustic behavior. The measured instruments' structural modes clearly impact their far-field directivity patterns, with the number of directional lobes corresponding to the associated structural mode shapes. Many of the lowest modes produce dipole-like radiation, with the dipole moment determined by the positions of the nodal and antinodal regions. Higher modes exhibit more complex patterns with multiple lobes often correlated with the location and number of antinodal regions on the gong's edge. Directivity indices correspond to dipole radiation at low frequencies and quadrupole radiation at intermediate and higher frequencies. Symmetry analysis confirms that the gong's rim significantly impacts the resultant directivity.
Human cytomegalovirus attenuates AKT activity by destabilizing insulin receptor substrate proteins
Authors: Domma Anthony J. , Henderson Lauren A. , Goodrum Felicia D. , Moorman Nathaniel J. , Kamil Jeremy P.
Published: September 2023

The phosphoinositide 3-kinase (PI3K)/AKT pathway plays crucial roles in cell viability and protein synthesis and is frequently co-opted by viruses to support their replication. Although many viruses maintain high levels of AKT activity during infection, other viruses, such as vesicular stomatitis virus and human cytomegalovirus (HCMV), cause AKT to accumulate in an inactive state. To efficiently replicate, HCMV requires FoxO transcription factors to localize to the infected cell nucleus (Zhang et al. mBio 2022), a process that is antagonized by AKT. Here, we investigated how HCMV inactivates AKT to achieve this. Results from subcellular fractionation and live-cell imaging studies indicated a defect in the recruitment of AKT to membranes upon serum stimulation of HCMV-infected cells. UV-inactivated virions failed to inactivate AKT, suggesting a requirement for
de novo
viral gene expression. Through additional studies, we identify that UL38 (pUL38), a viral activator of mTORC1, inactivates AKT by destabilizing insulin receptor substrate-1 (IRS1), a protein that recruits PI3K to growth factor receptors. Decreased electrophoretic mobility and diminished expression of IRS1 correlated with the accumulation of UL38 protein during infection. However, destabilization of IRS1 and loss of AKT activity did not occur in cells infected with an HCMV mutant disrupted for
UL38
nor when mTORC1 was inhibited by rapamycin. Finally, ectopic expression of UL38 in uninfected cells sufficed to cause IRS1 degradation and AKT inactivation, and these effects were likewise reversed by rapamycin. Collectively, our results demonstrate that HCMV relies upon a cell-intrinsic negative feedback loop to render AKT inactive during productive infection.

IMPORTANCE

Human cytomegalovirus (HCMV) requires inactivation of AKT to efficiently replicate, yet how AKT is shut off during HCMV infection has remained unclear. We show that UL38, an HCMV protein that activates mTORC1, is necessary and sufficient to destabilize insulin receptor substrate 1 (IRS1), a model insulin receptor substrate (IRS) protein. Degradation of IRS proteins in settings of excessive mTORC1 activity is an important mechanism for insulin resistance. When IRS proteins are destabilized, PI3K cannot be recruited to growth factor receptor complexes, and hence, AKT membrane recruitment, a rate limiting step in its activation, fails to occur. Despite its penchant for remodeling host cell signaling pathways, our results reveal that HCMV relies upon a cell-intrinsic negative regulatory feedback loop to inactivate AKT. Given that pharmacological inhibition of PI3K/AKT potently induces HCMV reactivation from latency, our findings also imply that the expression of UL38 activity must be tightly regulated within latently infected cells to avoid spontaneous reactivation.
Neuraminidase-dependent entry of influenza A virus is determined by hemagglutinin receptor-binding specificity
Authors: Wallace Louisa E. , de Vries Erik , van Kuppeveld Frank J. M. , de Haan Cornelis A. M.
Published: September 2023

Influenza A viruses (IAVs) contain sialoglycan-binding hemagglutinin (HA) and sialoglycan-cleaving neuraminidase (NA) proteins, the concerted action of which is needed for escape from decoy receptors and for virion motility ultimately resulting in infection of epithelial cells of the respiratory tract. The importance of NA in egress of newly assembled virions has been well established, whereas its role in entry has yet to be fully elucidated. In this study, we systematically analyzed the role of NA in viral entry in relation to HA receptor-binding preference, the receptor repertoire displayed on cells and the presence of mucus decoy receptors. Utilizing recombinant viruses that differ only in their HA-NA composition, it was observed that the dependence on NA activity for IAV entry largely depends on HA and not NA, with entry of α2–6 sialoglycan-binding viruses being inhibited more by NA inhibitor (oseltamivir carboxylate; OsC) than α2–3 sialoglycan-preferring viruses. In agreement with this, inhibition of virus entry by OsC could be modified by altering the sialoglycan receptor repertoire of cells. Entry inhibition by OsC correlated with the ability of mucus to inhibit infection, with the combination of the two having the largest effect. Our results indicate that the dependency of IAV on NA activity and, thus, virion motility for entry are determined by the receptor-binding properties of HA in combination with the receptor repertoire present on cells. This dependency is larger when fewer preferred receptors are displayed, which coincides with increased inhibition by mucus decoy receptors.

IMPORTANCE

Influenza A viruses (IAVs) contain hemagglutinin (HA) proteins involved in sialoglycan receptor binding and neuraminidase (NA) proteins that cleave sialic acids. While the importance of the NA protein in virion egress is well established, its role in virus entry remains to be fully elucidated. NA activity is needed for the release of virions from mucus decoy receptors, but conflicting results have been reported on the importance of NA activity in virus entry in the absence of decoy receptors. We now show that inhibition of NA activity affects virus entry depending on the receptor-binding properties of HA and the receptor repertoire present on cells. Inhibition of entry by the presence of mucus correlated with the importance of NA activity for virus entry, with the strongest inhibition being observed when mucus and OsC were combined. These results shed light on the importance in virus entry of the NA protein, an important antiviral drug target.