bluuebunny/crossref_metadata_2025_split huggingface dataset:
Economic Feasibility Analysis of Developing Large-Scale Hybrid Solar-Wind Energy Plants on Farms and Ranches in South Texas
Authors: Giuffrida Jose , Cruz Mariee , Martinez-Gomez Erick , Ludtke Sophia , Li Hua 
Published: September 2023

Abstract
Renewable energy is considered one of the most promising strategies to reduce the use of fossil fuels in society. However, the initial cost is the concern that has been consistently identified as the main obstacle to market penetration of renewable energy systems. The purpose of this research is to evaluate the economic feasibility of the implementation of hybrid solar-wind energy plants on farms and ranches in South Texas. To carry out this study, four farms were selected in four different counties according to a set of criteria: distance to major cities, access to existing infrastructures including transmission lines and roads, available land, and wind and solar energy potentials in the area. One potential farm or ranch was selected from each county, and five different scenarios have been analyzed ranging from 100% wind to 100% solar for each selected farm or ranch. 100 MW was selected as the nameplate capacity of all the scenarios. HOMER Pro software was used to conduct the economic feasibility analysis. Net present cost, annual worth, present worth, return on investment, payback period, and levelized cost of energy were calculated and compared between different scenarios and different counties, which helped identify the best scenario for each county. The results also show the changes in the economic feasibility of developing large-scale hybrid solar-wind energy plants in different counties depending on the resources available in the area.
Status Quo of Heliostat Field Deployment Processes
Authors: Sment Jeremy , Zolan Alexander , Zhu Guangdong 
Published: September 2023

Abstract
Deployment of the solar field of a concentrating solar power plant is one of many factors that are integral to the success of a project. Knowledge transfer from outside the industry is limited due to the unique nature of heliostats, which redirect sunlight to a receiver with high precision while maintaining a high level of reflectivity. Moreover, learning from project to project can be limited due to the site-specific nature of projects, as the market includes several developers, each with their own unique design. In this paper, we discuss the state of the art in heliostat field deployment. We cover all the key aspects of deployment from project assessment to a fully functioning system, which include site selection, layout development, supply chain, assembly, site preparation and construction, calibration, and operations and maintenance.
Energy and Exergy Analysis of a Locally Developed 6W VRE Mobile Solar Charger
Authors: Gothaang Phodiso , Masoso Okatoseng T. , Nwaigwe Kevin N. 
Published: September 2023

Abstract
Following the intensified shift to a mixed-mode teaching and learning approach, a common challenge faced by students at the University of Botswana is a scarcity of charging points. Most charging points are indoors and not adequate for the student population. Even when available, indoor charging stations have no provision for chargers, hence the development of a mobile charging station equipped with all classes of chargers. In this study, an investigation of the energy and exergy performance of the locally developed 6W charging station, designed to improve charging convenience to the University of Botswana community, is undertaken. In carrying out the energy and exergy analysis, measurements of irradiance, wind speed, voltage, and current were undertaken for the existing system at intervals of 30 minutes and the results were analyzed. The solar station analysis indicated maximum and average energy efficiencies of 14.15 % and 11.92 % respectively, an exergy efficiency average of 5.44 %, and an exergy efficiency maximum of 12.16 %. The system achieved a power conversion efficiency of 12.9 % and a 1.24 % increase in the exergy efficiency after it was modified. At high module temperatures, the performance of the module was severely affected as the losses were high. Results achieved from the extensive performance analysis of the developed 6W system will help improve the energy and exergy performance of the system.
Experimental Study on the Effect of Uneven Heat Load on the Airflow Uniformity and Thermal Performance in a Small-Scale Data Center
Authors: Chang Ze-Wen , Wang Chi-Chuan 
Published: September 2023

Abstract
This study focuses the effect of uneven loading on the flow distribution across the data racks subject to a raised flow simulated small data center. A total of 10 data racks having a total thermal power of 50 kW is investigated. Tests are conducted for both semi-enclosed and fully enclosed cold aisle. For the even power case, all the data racks are operated with 5 kW, and for uneven case, one side of the data racks contains 7.5 kW heat generation for each data rack and the other side of data racks is 2.5 kW. The tested flowrates are 2.4 CMS and 3.4 CMS, respectively. Yet both semi-enclosed and fully enclosed cold aisle are tested in this study. It is found that for a higher supply volumetric flowrate of 3.4 or 2.4 CMS, the effect of maldistribution for even power case is rather small for the case of uniform heating load. Conversely, for semi-enclosed cold aisle, load, the difference in air volumetric flowrate on both sides has increased significantly, the hotter racks contain higher flowrate. The flow mal-distribution accounts for 6% at a flowrate of 3.4 CMS, and the difference is amplified to 12% for a smaller air flowrate of 2.4 CMS. For the fully enclosed cold aisle at a higher flowrate of 3.4 CMS subject to uneven heating load, the flow mal-distribution in both sides is insignificant. However, mal-distribution for uneven heating load may occur when the supplied flowrate is reduced to 2.4 CMS for the fully enclosed arrangement.
Effects of Natural Convection Mass Transfer on Drying Aerogels With Supercritical Carbon Dioxide
Authors: Abolorunke Friday N. , Dinh Hy , Karamanis Georgios , Remella Karthik , Hodes Marc 
Published: September 2023

Abstract
In manufacturing silica aerogels, the alcohol solvent is often extracted from a wet gel via supercritical carbon dioxide (SCCO2) drying to avoid, during the majority of the drying process, crossing the liquid-vapor phase boundary and thus prevent capillary forces from collapsing the delicate mesoporous structure. Our understanding of the relevant physics is limited due to the complex phenomena involved in this transport process. Therefore, a rigorous model that captures the underlying physics is essential to understand the transport phenomena for scaling up the drying process and reducing overall manufacturing costs. Several studies that model the SCCO2 drying of aerogel have ignored the effect of natural convection on the extraction rate. Here, we developed a 3D model to capture the natural convective mass transfer due to variation in fluid density as the concentration of carbon dioxide CO2 changes in an ethanol-carbon dioxide mixture. The geometry is an annular gel concentric with an open region where SCCO2 flows. The aerogel is modeled as a porous medium where the flow is modeled using Darcy’s law. We solve the compressible forms of the momentum, continuity, and species equations that govern and couple the transport in the open region and the porous medium. Also, we account for the variation in molecular diffusivity in the species transport equation using a mass-fraction-dependent diffusion coefficient. We show the changes in the mass transfer rates relative to the case where natural convection is ignored to be substantive.
Multimodal Characterization of Steady-State and Transient Boiling Heat Transfer
Authors: Pandey Hari , Dunlap Christy , Williams Amanda , Marsh Jackson , Hu Han 
Published: September 2023

Abstract
Boiling is a high-performance heat dissipation process that is central to electronics cooling and power generation. The past decades have witnessed significantly improved and better-controlled boiling heat transfer using structured surfaces, whereas the physical mechanisms that dominate structure-enhanced boiling remain contested. Experimental characterization of boiling has been challenging due to the high dimensionality, stochasticity, and dynamicity of the boiling process. To tackle these issues, this paper presents a coupled multimodal sensing and data fusion platform to characterize boiling states and heat fluxes and identify the key transport parameters in different boiling stages. Pool boiling tests of water on multi-tier copper structures are performed under both steady-state and transient heat loads, during which multimodal, multidimensional signals are recorded, including temperature profiles, optical imaging, and acoustic signals via contact acoustic emission (AE) sensors, hydrophones immersed in the liquid pool, and condenser microphones outside the boiling chamber. The physics-based analysis is focused on i) extracting dynamic characteristics of boiling from time lags between acoustic-optical-thermal signals, ii) analyzing energy balance between thermal diffusion, bubble growth, and acoustic dissipation, and iii) decoupling the response signals for different physical processes, e.g., low-to-midfrequency range AE induced by thermal expansion of liquids and bubble ebullition. Separate multimodal sensing tests, namely a single-phase liquid test and a single-bubble-dynamics test, are performed to reinforce the analysis, which confirms an AE peak of 1.5 kHz corresponding to bubble ebullition. The data-driven analysis is focused on enabling the early fusion of acoustic and optical signals for improved boiling state and flux predictions. Unlike single-modality analysis or commonly-used late fusion algorithms that concatenate processed signals in dense layers, the current work performs the fusion process in the deep feature domain using a multi-layer perceptron regression model. This early fusion algorithm is shown to lead to more accurate and robust predictions. The coupled multimodal sensing and data fusion platform is promising to enable reliable thermal monitoring and advance the understanding of dominant transport mechanisms during boiling.
Visualization-Aided Experimental Study of Thermal and Hydraulic Characteristics of Subcooled Flow Boiling of R-134A in a Microchannel Evaporator of a Pumped Two-Phase Loop
Authors: Kokate Rohan , Park Chanwoo 
Published: September 2023

Abstract
Conventional liquid cooling systems based on relatively inefficient forced convection are often not capable of handling high heat dissipation rates, especially for high-power electronics. A pumped two-phase loop (P2PL), which is an active two-phase cooling system, uses two-phase heat transfer (boiling and condensation) which is efficient and capable of handling high heat fluxes and is an order of magnitude higher than the forced convection of liquid cooling. In this study, an experimental investigation was performed using P2PL with R-134a for analyzing subcooled flow boiling in a microchannel evaporator. The ranges of mass flux are from 47.9 to 143.8 kg/m2-s, heat flux from 0 to 34 W/cm2, and quality from subcooled to critical heat flux. Flow visualization using a sight glass tube at the outlet of the evaporator was employed to investigate the influence of heat flux and mass flow rate on the two-phase flow patterns. Five two-phase flow regimes — nucleate boiling, bubbly flow, slug flow, stratified flow, annular flow, and misty flow — were identified based on the flow visualization which coincides perfectly with the slope changes of the boiling curve. The results of this study show that for a fixed wall temperature, in the convective boiling dominant region heat flux dissipation increases with mass flux, while it remains independent of mass flux in the nucleate boiling dominant region. A peak heat transfer coefficient was observed at a high exit vapor quality which corresponds to the annular flow regime with thin-film evaporation. The transient responses were used to characterize the single-phase and two-phase flows along with the critical heat flux (CHF) by investigating the dryout propagation in the microchannel. Further, the evaporator pressure drop increased linearly with heat flux in the two-phase regimes with the point of minimum pressure drop occurring at a heat flux beyond the Onset of Nucleate Boiling (ONB).
Phase Change Materials for Absorbing Peak Heat Loads in Aircraft: An Effectiveness-NTU Model for Predicting the Performance of Compact Heat Exchanger
Authors: Frank Julie Y. , Borman Duncan J. , Greiciunas Evaldas , Khan Amirul , Summers Jon 
Published: September 2023

Abstract
Thermal Management Systems (TMS) have been identified as one of the limiting factors in the design of future aircraft. A PCM heat exchanger could be added to TMS to help relieve the heat load on current technologies in aircraft. To date, compact PCM heat exchangers adapted for the use in aerospace have received limited attention in the literature. In this work, an effectiveness-NTU model for a PCM compact heat exchanger is proposed based on a simplified Stefan condition which could be used for the initial sizing of the PCM heat exchanger based on a given thermal loading profile. This approach significantly reduces the computational expense of the model when compared to solving the Stefan condition in an ODE system, while still accounting for the melting/solidification cycle length. As such, it is possible to directly obtain realistic dimensions for the PCM channel for a non-finned case from the model. Results show good energy conservation, which builds confidence in the model, and similar trends are observed to what has previously been described in CFD studies and experimental results.
Flow Interference Between Tandem Cylinder With Forced Convection in Staggered Position
Authors: Sarout Yuvraj , Islam Md. , Fatt Yap , Janajreh Isam 
Published: September 2023

Abstract
Flow-induced vibration of the filleted (rounded corner) oscillating cylinder is numerically investigated at Re = 150 and Pr = 0.7. The upstream cylinder (UC) is static while the downstream cylinder (DC) is elastically mounted which is allowed to vibrate in the transverse direction with a spacing ratio (L/D) = 5 and staggered angle (α) of 45°. Square cylinder is gradually filleted into the circular cylinder by changing r* (filleted radius) = 0 (square cylinder), 0.5, 0.75 and 1 (circular cylinder). Computations were carried out for reduced mass m* = 10 and varying reduced velocity (Ur) = 2, 4, 6, 8 and 10, structural damping constant is set to be zero which gives rise to high vibrational amplitude. Both cylinders were maintained at a constant temperature (T* = 1) while the upcoming flow is set to be at T* = 0. Vibrational characteristics are scrutinized with help of frequency characteristics of vibrating cylinder, vibrational amplitude, drag coefficient, lift coefficient and instantaneous z-vorticity contours. When natural frequency (fn) and vortex shedding frequency (fs) overlap, it causes synchronization or lock-in. The lock-in phenomenon usually occurred at Ur = 6 leading to higher vibrational amplitude for all geometries and dropped at Ur = 8 but persisted at Ur = 8 and 10 for r* = 0. Due to higher vibrational amplitude, the flow structure is more complicated at Ur ≥ 6. The maximum value of average Nusselt number (Nuavg) is at Ur = 6 for circular DC, whereas the minimum lies at Ur = 2 for square upstream cylinder. Generated results envisage results of flow interferences and forced convection of tube arrays in heat exchangers and marine structures. Understanding the mechanisms of flow-induced vibration in staggered cylinders is crucial for designing and optimizing these systems, as well as for ensuring their safe and reliable operation.
An Air Conditioning Cycle Using Lower Critical Solution Temperature Mixtures
Authors: Kocher Jordan D. , Menon Akanksha K. , Yee Shannon K. 
Published: September 2023

Abstract
The refrigerants and electricity consumption of existing air conditioning systems create significant greenhouse gas (GHG) emissions. This work describes a new air conditioning cycle that uses a lower critical solution temperature (LCST) liquid mixture to provide dehumidification and cooling. The cycle uses no refrigerants and is driven by low-grade heat. Upon heating, the LCST mixture phase separates into a water-rich phase and a water-scarce phase. After cooling both phases to ambient temperature, the water-scarce phase absorbs moisture from humid air (providing dehumidification), while the water-rich phase desorbs water to the outdoor air (providing evaporative cooling). In this work, we theoretically develop and experimentally demonstrate this cycle for the first time, using three different LCST mixtures. A ternary mixture of oleic acid, lidocaine, and water showed the best performance by dehumidifying air to ∼86% relative humidity, while the other LCST mixtures we investigated were only able to dehumidify to ∼98% relative humidity. While a relative humidity of 86% is still too high for thermal comfort, this first investigation of a new cycle motivates further investigation into other LCST mixtures. Future discoveries could lead to new mixtures that can reach lower humidities. To this end, we derive the thermodynamic equations that govern LCST liquid mixtures and determine the enthalpy and entropy of mixing that these hypothetical future LCST mixtures would possess.
The Effect of Inlet and Outlet Configuration on the Performance of Hollow Fiber Direct Contact Membrane Distillation
Authors: Asiri Jaber M. , Caspar Justin , Xue Guanyang , Oztekin Alparslan 
Published: September 2023

Abstract
Hollow fiber microporous membranes have been used widely in membrane distillation (MD) for seawater desalination applications due to their high surface area. The configurations of feed inlets and outlets significantly impact the performance of hollow fiber direct contact membrane distillation (HF-DCMD). An increase in feed inlets and outlets can also profoundly affect the system’s performance by reducing the concentration polarization at the membrane surface and increasing the mass transfer rate. These aspects are critical when designing and optimizing HF-DCMD systems for various applications such as water desalination and wastewater treatment. Computational fluid dynamics (CFD) simulations were implemented to investigate the performance of HF-DCMD for a desalination process. The effect of inlet and outlet configuration in a tubular shell filled with hollow fiber membranes is examined in modules with a 31% packing ratio. The feed solution with a concentration of 35 g/L NaCl flows in the shell side while the permeated water flows inside the hollow fibers. The Navier-Stokes, mass and energy transport equations for laminar flows are solved with a coupled boundary condition to model the desalination process in the module. Various feed inlet and outlet configurations are considered, including one with an inlet and outlet normal to the shell’s axis (at the shell’s end surfaces) and others with inlets and outlets parallel to the axis. The module with an inlet and outlet at each shell end parallel performs better than other configurations. The permeate flux is enhanced by approximately 153% when four feed inlets are placed at the side wall of the shell. On the other hand, the study observed a slight increase in water production when multiple feed outlets are used.
Optimized Design and Control of a Multi-Temperature, Multi-Module Thermal Energy Storage Ensemble
Authors: Cooney Alanna Y. , Carey Van P. 
Published: September 2023

Abstract
Latent thermal energy storage (LTES) systems which store energy in a phase change material (PCM) are effective in bridging the gap between renewable energy supply and demand for applications such as concentrated solar plants and building heating and cooling systems. Cascaded LTES systems which use multiple PCMs with different melt temperatures can be used to improve performance by increasing energy and exergy efficiencies and increasing rates for charging and discharging. A multi-temperature, multi-module (MTMM) LTES ensemble controlled by an Artificial Neural Network (ANN) can further improve performance by allowing for various working fluid flow paths through the system which allow for the ensemble to adapt to dynamically changing and unforeseen operating conditions. The MTMM ensemble is optimized to control to dual objectives of meeting a target working fluid outlet temperature and minimizing the instantaneous rate of exergy destruction allowing it to both achieve operational reliability and maximize second law efficiencies. In this investigation, design optimization of the MTMM ensemble is explored by comparing various parallel and series configurations of modules and exploring the effects of TES module layout, PCM melt temperatures, and the overall heat transfer coefficient of individual modules on the performance of the ensemble. The results demonstrate the impact of optimization of design parameters on the performance of MTMM ensembles and the potential for the use of data driven optimizers such as genetic algorithms for design of MTMM ensembles. The performance of the MTMM ensemble with optimized design and adaptive ANN controller is demonstrated to achieve the exergy efficiency of a cascaded PCM system while also maintaining the flexibility needed to respond to dynamically changing operating conditions. This novel approach widens the potential applications of cascaded PCM by providing a means to standardize manufacturing to drive down system cost and allowing the system to adapt to dynamic operating conditions and unforeseen design parameters.
Preliminary Baseline Vestibular Ocular Motor Screening Scores in Pediatric Soccer Athletes
Authors: Anderson Morgan , Tomczyk Christopher P. , Zynda Aaron J. , Pollard-McGrandy Alyssa , Loftin Megan C. , Covassin Tracey 
Published: September 2023

Context: The utility of baseline vestibular and ocular motor screening (VOMS) in high school and collegiate athletes is demonstrated throughout the literature; however, baseline VOMS data at the youth level are limited. In addition, with the recent adoption of the change scoring method, there is a need to document baseline VOMS total and change scores in a pediatric population. Objective: To document baseline VOMS total and change scores and to document the internal consistency of the VOMS in pediatric soccer athletes. We hypothesized that the VOMS would demonstrate strong internal consistency in pediatric soccer athletes. Design: Cross-sectional study. Methods: Pediatric soccer athletes (N = 110; range = 5–12 y) completed the VOMS at baseline. Descriptive statistics summarized demographic information, VOMS total scores, and VOMS change scores. Cronbach α assessed internal consistency for VOMS total scores and change scores. Results: Twenty-one (19.1%) participants had at least one total score above clinical cutoffs (≥2 on any VOMS component and ≥5 cm on average near point convergence). Forty (36.4%) participants had at least one change score above clinical cutoffs (≥1 on any VOMS component and ≥3 cm on average near point convergence). The internal consistency was strong for total scores with all VOMS components included (Cronbach α = .80) and change scores (Cronbach α = .89). Conclusions: Although results suggest VOMS items measure distinct components of the vestibular and ocular motor systems, caution should be taken when interpreting VOMS total and change scores in pediatric athletes, as overreporting symptoms is common, thereby impacting the false-positive rate.