bluuebunny/crossref_metadata_2025 huggingface dataset:
The urban–rural gap in older Americans’ healthy life expectancy
Authors: Chapel Jack M. , Currid‐Halkett Elizabeth , Tysinger Bryan
Published: September 2024

Purpose

Estimate health‐quality‐adjusted life expectancy (QALE) for Americans nearing retirement age and assess rural–urban disparities in QALE.

Methods

We used a dynamic microsimulation model based on Health and Retirement Study data to estimate the quantity and health quality of expected future life years for rural and urban Americans ages 59–60 in 2014–2020.

Findings

Cohort life expectancy at age 60 (LE) for urban and rural men was 22.9 and 20.9, respectively; for urban and rural women, LE was 25.6 and 25.0, respectively. Adjusting future life years to quality‐adjusted life years, QALE was 17.5 versus 15.7 for urban versus rural men, and 19.3 versus 18.7 for women. Compared to a cohort in 1994–2000, the urban–rural QALE gap in 2014–2020 grew substantially for men; changes for women were smaller. Average QALE masked heterogeneity by race/ethnicity, education, and Census region. Counterfactual scenarios suggested eliminating smoking and managing obesity and prevalent heart conditions would be particularly beneficial for increasing rural QALE and reducing the urban–rural gap.

Conclusions

Expected health quality, in addition to longevity, is an important factor when assessing rural disparities in older Americans’ future life outcomes. Current chronic disease disparities are expected to translate to a widening urban–rural gap in QALE, particularly for men. Interventions earlier in life may be needed to fully address disparities in QALE at older ages.
Efficacy of digital brief behavioural treatment for insomnia using a smartphone application in conjunction with light therapy in university students with insomnia symptoms with late chronotypes: A pilot randomized–controlled trial
Authors: Furihata Ryuji , Shimamoto Tomonari , Ikeda Yurina , Makino Yuto , Nakagami Yukako , Tateyama Yukiko , Okabayashi Satoe , Akahoshi Toshiki , Kiyohara Kosuke , Iwami Taku
Published: September 2024

The efficacy of digital brief behavioural treatment for insomnia using a smartphone application in conjunction with light therapy was investigated in university students who had insomnia symptoms with late chronotypes. In this two‐arm parallel randomized–controlled trial, participants with insomnia symptoms and late chronotypes were recruited between October and November 2023. The duration of the intervention program was 4 weeks. The smartphone application provides digital brief behavioural treatment for insomnia, including programs for advanced phases. The intervention group used blue‐light‐emitting diode glasses in the morning after waking up for 2–4 weeks. The primary outcome was a change in the Insomnia Severity Index during the study period. The Insomnia Severity Index was obtained weekly using a web questionnaire. Of the 28 students, 14 each were assigned to the intervention and control groups. The mean Insomnia Severity Index scores at baseline were 12.2 and 12.5; after 4 weeks, they declined to 7.2 and 10.6 in the intervention and control groups, respectively. Primary analysis using a linear mixed model showed a significant improvement in the temporal trends of the Insomnia Severity Index in the intervention group (p < 0.001). The scores on the Morningness–Eveningness Questionnaire (p = 0.008) and RU‐SATED (p = 0.005) significantly improved in the intervention group relative to the control group following the intervention. This study demonstrated the effectiveness of the digital brief behavioural treatment for insomnia with light therapy in participants with both insomnia symptoms and late chronotypes.
Review: Food‐induced mucosal alterations visualized using endomicroscopy
Authors: Balsiger Lukas Michaja , Rusticeanu Monica , Langhorst Jost , Sina Christian , Benamouzig Robert , Huang Clifton , Tack Jan , Kiesslich Ralf
Published: September 2024

Confocal laser endomicroscopy (CLE) is a novel technique allowing real time in vivo microscopy during standard endoscopy. Recently, acute mucosal alterations after food administration visualized by CLE have been linked to symptoms in irritable bowel syndrome (IBS). Interestingly, the observed reactions occurred in subjects without demonstrable allergic sensitization to food—this is in line with mechanistic research showing local but not systemic allergic sensitization to foods in an animal model for IBS. Here, European experts conducting CLE with food administration provide a narrative review of the available literature and propose practical guidance on the use of this technique. CLE allows physicians to observe acute mucosal reactions after the application of food to the duodenal mucosa in patients with functional gastrointestinal disorders. Some open‐label interventions show a symptomatic benefit when patients exclude the nutrient that triggered an acute mucosal reaction. However, many technical, mechanistic, and clinical questions remain unanswered to date. Technically, the interobserver variability and learning curve requires systematic evaluation and criteria or cutoffs for alterations require validation. Mechanistic studies are needed to enhance our understanding of the mechanisms underlying observed alterations. Finally, rigorous blinded controlled studies are needed to assess a link of these observed alterations with symptom generation. CLE offers a platform allowing scientific insights related to food induced acute mucosal alterations. However, many questions remain unanswered, and more research is warranted to understand the role of acute mucosal alterations visualized upon food administration in IBS pathophysiology and treatment.
Between acceptance and resistance: Conceptualising migrant platform labour agency in Chile
Authors: Bonhomme Macarena , Ustek‐Spilda Funda , Arriagada Arturo
Published: September 2024

Digital labour platforms are transforming labour markets worldwide, and migrant workers are pivotal in this transformation. Drawing on a qualitative study in Chile, we uncover how Latin American and Caribbean migrants navigate and resist platform labour conditions, considering the algorithmically controlled and surveilled aspects of food delivery platforms, as well as the impact of migration status on their work. We contend that understanding migrant labour agency requires examining both the platforms' socio‐technical structures and the host country's migration policies. These policies determine workers' migration status, shape their work experiences, and consequently impact their resistance to precarious labour conditions. We introduce the concept of migrant platform labour agency to illustrate the various forms of resistance migrants employ in navigating the platform labour market. This concept contributes to understanding the nuances in migrants' labour agencies, which range from acceptance to resistance, considering the interplay between the migration policy environment and platforms' socio‐technical assemblage.
Is it moral to punish a criminal both during his lifetime and posthumously
Authors: Weiler Gur Arye Adam , Ori Meshi
Published: September 2024

We seek to probe into the question of whether it is moral to administer a punishment on a criminal both in his lifetime and posthumously. Is it moral to punish a murderer both during his lifetime by sentencing him, for instance, to life imprisonment, and posthumously—let us assume—by burial in a separate section of the cemetery exclusively assigned for murderers, which would perpetuate their ignominy? We consider that a discussion of this crux might raise valuable insights and questions regarding the philosophy of punishment. We will aim to examine this issue from several perspectives: utilitarianism, retributivism, and expressivism. Moreover, we shall consider it as a means for preventing an exacerbation of the punishment by more cruel means. Furthermore, we will point out some problems which should be considered that may arise from the posthumous penalty.
Use of Cystourethroscopy to Define the Gross Tumour Volume in Radiation Treatment Planning for Canine Genitourinary Carcinomas
Authors: Freemyer Clarissa C. , Gieger Tracy L. , Vaden Shelly L. , Nolan Michael W.
Published: September 2024

Radiotherapy (RT) is increasingly utilised for definitive‐intent treatment of canine genitourinary carcinomas (CGUC). At our institution, the standard approach is to irradiate tomographically abnormal tissues gross tumour volume (GTV) plus a clinical target volume (CTV) expansion of 2 cm. Cystourethroscopy is often incorporated into the treatment planning workflow, though an optimal approach has yet to be defined. This observational study evaluated cystourethroscopy as a tool for identifying gross lesions that can be targeted with RT. We hypothesised that in most cases, addition of cystourethroscopy would result in a larger GTV than would be drawn with computed tomography (CT) alone. Medical records from 54 dogs diagnosed with CGUC between 2013 and 2023 were reviewed; each had been evaluated before RT using CT and cystourethroscopy. The GTV was initially defined as the tomographically evident disease on a post‐contrast sagittal plane CT scan, and then lesions visualised with cystourethroscopy (suspected or confirmed to be tumour) were added. Beyond what was visible on CT, cystourethroscopy extended the GTV by a median of 6.5 cm distally into the urethra (range: 1.5–31.8 cm) and therefore resulted in GTV enlargement in 26 of 54 (48%) cases. Addition of our standard 2 cm CTV expansion to a CT‐defined GTV (without use of data from cystourethroscopy) would have underestimated the extent of grossly abnormal tissue in 35% (19/54) of cases. These results suggest that incorporating cystourethroscopy into treatment planning workflows may improve local tumour control by reducing the risk of a geographic miss.
Comprehensive Analysis of Input Shaping Techniques for a Chain Suspended From an Overhead Crane
Authors: Alghanim Khalid , Alobaid Faisal
Published: September 2024

This work investigates the use of input shaping techniques for controlling oscillations in a chain suspended from an overhead crane, aiming to enhance crane operations without sacrificing speed or safety. The study focuses on two specific input shaping strategies: step-input and polynomial-input shapers. The step-input shaper applies discrete changes at determined intervals, whereas the polynomial-input shaper utilizes a continuous function to adjust the crane's input throughout its operation. Numerical simulations assess the effectiveness of these techniques in reducing oscillations across various vibration modes of the chain and examine their impact on overall system performance metrics such as maneuver time, kinetic energy, robustness, and operational smoothness. Results from comprehensive simulations indicate that both input shapers significantly eliminated residual vibrations found in time-reduced inputs. The polynomial-input shaper demonstrated enhanced performance in decreasing the residual kinetic energy, and it promoted smoother operation and better adaptability to variations in chain length.
Comprehensive Evaluation of Microscopic Movability and Macroscopic Productivity of Continental Shale Reservoir
Authors: Li Guoxin , Jin Xu , Shen Yinghao , Tao Jiaping , Liu Chang , Wu Songtao , Xian Chenggang , Liu He
Published: September 2024

Continental shale oil is diversified, differentiated, and complex. It has disadvantages such as low production and inferior development benefits. Given this, the movability and productivity of shale oil were proposed in this research to evaluate the producible capacity and development potential of shale oil. Taking the Yingxiongling shale oil reservoir as an example, the microscopic movability and macroscopic productivity of the main lithofacies were systematically investigated via the NMR tests, imbibition experiments, uniaxial compression tests, and CT imaging. The characteristics of different lithofacies were clarified, and the favorable targets were identified. The results showed that the layered limy dolomite of the shale oil reservoir has the highest microscopic movability, followed by that of the laminated limy dolomite and the least of the laminated clayed shale. The laminated limy dolomite has better fluid flow properties, higher capacity to form fracture networks, and the best macroscopic productivity. The layered limy dolomite has medium macroscopic productivity, and that of the clayed shale is the least. Based on the field testing and experimental understanding of layered limy-dolomitic shale as high-quality targets, the laminated limy-dolomitic shale is further identified as a favorable target. It features a stronger capacity to form fracture networks, better imbibition performance, medium microscopic movability, and relatively high macroscopic productivity. This research further clarifies the correlation between microscopic movability and macroscopic productivity and provides theoretical support for exploring and developing the continental shale oil reservoir.
A Simple Approach to Transient-State Modeling of Nitrogen Cooling in the Extrusion of Light-Alloy Complex Profiles
Authors: Pelaccia Riccardo , Negozio Marco , Santangelo Paolo E.
Published: September 2024

Nitrogen cooling has become a popular solution to reduce heat flux between the die and the profile in the hot extrusion process. However, designing effective cooling channels for complex-shape profiles poses challenges, especially when the phase transition of nitrogen significantly impacts heat transfer with solid bodies. To this end, the ability to model both the liquid and the gas phases is instrumental in devising design strategies, yet it should be combined with low computational complexity for industrial applications. The present work is aimed at employing the homogenous-flow approach as a simple, yet representative methodology to consider both phases in the simulations. A one-dimensional model of nitrogen was combined with a three-dimensional extrusion model to perform the transient analysis of the whole process, mostly focused on the transition from fully gaseous to fully liquid flow. Validation using extrusion tests on 17 AA6060 billets demonstrates the model's predictability in comparison with a fully liquid model. The average error associated with the homogeneous flow model was evaluated as below 10%, whereas the fully liquid approach yielded 25%. That proved the ability of the proposed model to reproduce the cooling effect, thus supporting the design of the cooling subsystem within the context of the whole extrusion tooling.
Thermosiphon Cooling System for a Methanation Reactor: An Experimental Assessment
Authors: Aubin Philippe , Van herle Jan , Thome John R.
Published: September 2024

Operating the cooling system of a methanation reactor using an open-loop two-phase thermosiphon with evaporating water as the cooling liquid is an effective way to ensure safe operation as it does not rely on a recirculating pump. The aim of the reactor design is to co-generate methane and steam, the latter to be used in a solid-oxide electrolyzer to produce H2 to be injected in the reactor. The passive operation was analyzed to ensure a similar level of stability in the steam production compared to the active operation (i.e., with a pump). A total of 98% of the measured steam produced in passive cooling were within ±9.82% of the individual means, comparing well to ±9.5% for the active cooling operation.
AI for Energy Intensive Industry: A Hybrid Optimization Approach for Flexibility Service Providers
Authors: Fischer Martin , Hofmann René
Published: September 2024

This paper presents a hybrid optimization method for industrial prosumers to act as flexibility service providers. The proposed method is applied to an industrial company from the energy intensive industry participating in the European Power Exchange and the Austrian balancing market, specifically focusing on automatic Frequency Restoration Reserve. A company in the food processing industry, with on-site electrical and thermal power generation is used to demonstrate the hybrid approach. There, metaheuristics and Mixed Integer Linear Programming are combined to solve a bidding strategy problem with a subsequent unit commitment problem. As metaheuristics, a Genetic Algorithm and Particle Swarm Optimization were applied and their results compared.
Application of Molten Salt Thermal Energy Storage for Waste Heat Recovery in Iron and Steel Industry
Authors: Zhou Mingxi , Liu Ruochen
Published: September 2024

The iron and steel industry has abundant heat resources, but the recovery rate of waste heat is quite low. In this aspect, thermal energy storage technology offers a promising approach for the recovery of massive and intermittent waste heat, which is important for energy saving and emission reduction, as well as a crucial way to realize carbon peak and carbon neutrality. In this study, an overview of the distribution and characteristics of waste heat resources in steel industry is provided firstly. Then the potential of integrating molten salt thermal energy storage to production processes such as iron ore sintering, steelmaking and by-product gas power generation in steel mills is presented. Waste heat of hot sinter, converter flue gas and exhaust gas of the combusted by-product gas in boiler is recovered by molten salt and stored in two tanks. Finally, taking a steel plant in China as an example, we investigated the molten salt thermal storage system design for an idle 20MW by-product gas combustion boiler from technical and economic viewpoints. The results show that molten-salt thermal energy storage could not only decrease the bleeding rate of blast furnace gas, but also realize the peak-shaving of power load and economic savings.
Design of a Radiant Floor Heating and Domestic Hot Water System Using Thermal Waters in the Andean Region of Ecuador
Authors: Coppiano Sofia , Gamarra Yesika , Moreira Daniel , Soriano Guillermo
Published: September 2024

The use of alternative and sustainable energy sources is currently a topic of great relevance worldwide. In Ecuador, there is a significant potential for harnessing geothermal energy, and a gap exists in implementing technologies that can utilize this energy source. This paper presents a design for a heating and domestic hot water system that harnesses energy from hot springs. The system was specifically tailored for a block of hotel rooms in the tourist complex ‘Terjamanco’, situated in the community of Papallacta on the eastern slope of the Andes Mountain range in Ecuador. The design follows a formal design process and compares it with a current system based on electricity for heating and LPG for hot water. Furthermore, an economic analysis was performed comparing a conventional HVAC and water heating system with the geothermal energy-based proposed alternative with an optimization of construction materials for environmental conditions. Through TRNSYS, a simulation of the proposed and based system was conducted; it was concluded that the implementation of the proposed system, along with the use of suitable construction materials, can lead to savings of over 80% in electricity bills and fuel consumption, ultimately averting the emission of up to 20 tons of CO2 annually into the environment.
Performance Study of Biomass Pyrolysis, Char Gasification and Oxy-Fuel Combustion Integrated System
Authors: Liu Ruochen , Zhou Mingxi
Published: September 2024

To investigate the technical feasibility of integrating biomass pyrolysis, char gasification, and oxy-fuel combustion, Aspen Plus was applied to evaluate the performance of different systems. Three technical routes were proposed: “Route 1” and “Route 2” involve coupling oxy-fuel combustion with biomass pyrolysis and char gasification, aiming to utilize char gasification for recovering high-temperature flue gas, while “Route 3” only couples oxy-fuel combustion with biomass pyrolysis. Energy saving and fossil CO2 emissions were compared across different technical routes, and economic evaluations were conducted. Two feedstock types (Reed straw or Municipal solid waste, MSW) were selected for analysis. The results indicate that “Route 2” saves more NG consumption, accompanying an increase in flue gas flow rate. Due to the poor quality of MSW, the waste char gasification temperature is 10% lower than that of biochar, resulting in a lower combustible gas content (CO+H2) in syngas from waste char gasification compared to biochar gasification by 18% under identical feedstock input (1t/h) and flue gas recycle ratio (10% or 20%). Biomass demonstrates an advantage in reducing fossil CO2 emissions compared to MSW, particularly evident in “Route 2-Bio” where fossil CO2 emissions decrease by 95% compared to the “Normal” case. Without factoring in CO2 tax, the price of biomass is significant. In the scenario of a 46 tons/day oxy-fuel glass furnace, “Route 2” offers the most promising OPEX savings. As long as the price of biomass raw materials is below 870 RMB/ton, it can lead to OPEX savings. If CO2 tax is considered, biomass as a feedstock proves to be more competitive than MSW in OPEX savings.
Elastic Wall Deformation of Flexible Microchannels Caused by Inside Condensation Flow
Authors: Liu Ziqi , Wang Ji , Li Xingtao , Yu Shengyang
Published: September 2024

The elastic deformation of a flexible microchannel caused by condensation heat transfer of refrigerant FC-72 is experimentally investigated. The microchannel has a rectangular cross-sectional shape with a hydraulic diameter of 0.13 mm. The deformation of the elastic channel wall is measured using a white light confocal coaxial displacement sensor. The cooling temperature of 10–40 °C and the mass flow rate of 200 and 300 kg/(m2·s) are tested. The elastic wall deformation increased with decreasing cooling temperature and increasing mass flow rate. Surprisingly, the channel wall tends to thicken when sequential bubbles flow through. This phenomenon can be explained by the local fluid pressure decrease caused by condensation which is strong enough to cause the bubble to shrink quickly. This shrinking may leave a temporary vacuum in the liquid slug connecting two adjacent bubbles. In channels with soft wall, the vacuum pulls the flexible wall moving towards the inside of the channel, which is wall deformation observed in the experiments. Therefore, this wall deformation comes from condensation. The outcomes may support the design and optimization in soft device thermal management.
An Innovative Hydraulic Ram Pump System
Authors: Sharma Ashokkumar M. , Capocelli Cody , Dady Trevor , Alam Mohammad Ashikul
Published: September 2024

As we may take water accessibility for granted in the developed countries, there still exists great hardship in accessing viable water sources in a multitude of underdeveloped parts of the world. Since delivering water to higher altitudes above the common water sources requires pumping infrastructures; the absence of such facilities creates great difficulties in underdeveloped regions as the scarcity of available water causes large impacts on hydration, sanitation, agriculture, and other water-based necessities. To combat the aforementioned issues, the installation of a hydraulic ram pump system can effectively serve as a power-independent solution for delivering water to communities that face persistent struggles to obtain essential water needed to survive. The goal of the present study is to evaluate the performance of an innovative, hydraulic ram pump for an energy-independent solution to improve water accessibility. A customized ram pump design was experimented incorporating a 0.23 m long, 19.05 mm sized vertical tube above the flapper valve. This resulted a backpressure at the flapper valve facilitating the self-priming of the pump. With a decrease in the pump’s water delivery pressure, the pump’s hydraulic power output sizably increased with the maximum of 0.68 W at 38.6 kPa delivery pressure.
Challenges in the Use of Bio-Hybrid Fuels As Drop-in Fuels
Authors: Hofmeister Marius , Fischer Felix Justin , Boden Lukas , Schmitz Katharina
Published: September 2024

Bio-hybrid fuels are produced based on sustainable raw materials and green energies. This way a closed carbon loop can be realized, and a CO2-neutral production becomes feasible. Thus, they are a promising alternative to conventional fuels made of mineral oil. Within the cluster of excellence “The Fuel Science Center” bio-hybrid fuels are investigated on a holistic level. The cluster’s research work includes the development of methods for predicting fuel properties. By using these methods, fuels can be optimized and designed regarding their combustion behavior, efficiency, and emissions. Therefore, the targeted adjustment of fuel properties represents a further advantage over conventional fuels. An advantage of bio-hybrid fuels over other alternative energy sources, such as fuel cells or electrical energy, is the use of existing infrastructure in the form of an extensive network of filling stations and petrochemical industry production sites. To benefit from the mentioned advantages, material compatibility must be ensured. However, swelling of sealing materials, insufficient lubricating properties and deviating fluid mechanical properties are a major issue, since they lead to consequential failure in the automotive system.

The article is intended to highlight the problems regarding compatibility and discuss methods for improving the compatibility of bio-hybrid fuels.
Particle Handling in Particle-Based Pumped Thermal Energy Storage
Authors: Jeong Shin Young , Hirschey Jason , Shah Munjal , Gifford Jeffrey , Martinek Janna , Ma Zhiwen
Published: September 2024

A novel pumped thermal electricity storage system utilizes low-cost solid particles as storage media that can deliver high-temperature heat and generate power by a high-efficiency power cycle. A counterflow direct contact gas/particle fluidized bed heat exchanger is a key component in the storage system, facilitating efficient heat transfer between high-temperature media and working fluids. A comprehensive hydrodynamic analysis of the particle fluidized bed within the heat exchanger has been conducted, optimizing key parameters such as pressure drops, air superficial velocities, minimum fluidization velocities, and fluidization regimes. To ensure optimal fluidization conditions, an air distributor has been designed and fabricated. Particle handling mechanical systems that efficiently deliver particles at high temperatures are essential in the thermal storage system. Components such as L-valve, screw conveyor, and pneumatic conveyer were designed, fabricated, and tested for a prototype laboratory-scale fluidized bed heat exchanger system.
Facility LED Lighting System Upgrades With Constant Illumination Consideration
Authors: Guo Qi , Zhang Qinhe , Rosti Firouz , Zhao Cunzhi
Published: September 2024

This paper delves into the challenges encountered during the transition from traditional lighting to energy efficient LED lights during facility lighting system upgrades. An issue of particular concern arises when these lights are replaced on a one-to-one basis. This practice often leads to excessive brightness, resulting in problems such as employee discomfort and light pollution. To address this challenge, the paper proposes a systematic approach based on the constant illumination principle. This method aims to accurately determine the optimal quantity of lights needed during the upgrade process.

To illustrate the efficacy of the proposed approach, two lighting system redesign scenarios are present: Plan A with T8 lights and Plan B with LED lights. These scenarios highlight the importance of employing the constant illumination approach in facility lighting redesign projects. By adopting this approach, facilities can effectively embrace LED technology and subsequently, creating a comfortable work environment and promoting environmental sustainability.
Decarbonizing the Steel Processing Industry: A MILP-Based Assessment of Electrification and Hydrogen for Hot Rolling
Authors: Zabik Gabriela , Birkelbach Felix , Hofmann René
Published: September 2024

The steel processing industry confronts substantial challenges in decarbonization, particularly within the hot rolling process, due to uncertainties surrounding viable clean alternatives. The industry’s heavy reliance on fossil fuels necessitates a shift towards more sustainable options. The hot rolling process currently relies on natural gas fired industrial furnaces for reheating steel. Electrification and hydrogen utilization have emerged as promising clean alternatives, yet neither has achieved full maturity nor widespread application, leaving the industry at a crossroads. This paper conducts an economic and design assessment of two decarbonization scenarios for steel rolling mills. Emphasis is placed on evaluating the impact of a highly volatile grid on overall costs and analyzing the systems’ responses to grid volatilities. One scenario involves electrification using induction heating, while the other involves a switch to hydrogen, including local production. Employing mixed-integer linear programming (MILP), our objective is to minimize total annual costs (TAC), including investment and operational costs, while considering the feasibility of decarbonization pathways. Our approach includes the introduction of storage units — battery and hydrogen storage — to enhance system flexibility. Electricity price forecasts for Austria in 2050, representing a fully renewable grid, are used and capture grid volatilities and seasonal fluctuations. Results reveal that generally, electrification proves more efficient although it poses challenges within a volatile grid due to high peak demands. Conversely, the hydrogen scenario, with an electrolysis unit and storage options, effectively balances cost fluctuations. Storage units significantly impact the hydrogen scenario, reducing costs, while in the electrification scenario battery storage offers limited cost benefits. Furthermore, CO2 avoidance costs were calculated for both systems, revealing significant expenses associated with reducing CO2 emissions.
Solar Thermochemical Carbon Dioxide Splitting Using Ceria and Iron Aluminate Foam Devices and Simulation of a Plant System for Demonstration
Authors: Nakakura Mitsuho , Koyama Yoshiko , Shibuya Sofu , Warren Kent , Weimer Alan , Farrell Tucker , Asaoka Tatsunori , Matsubara Koji
Published: September 2024

An international research project has been undertaken to integrate a unique solar thermal processing reactor system with ceria and iron aluminate as active redox materials for CO2 splitting. Experimental investigations for CO2 splitting were conducted using a solar simulator and tube furnace at Niigata University, followed by demonstrations using a high-flux solar furnace (HFSF) at the National Renewable Energy Laboratory (NREL) in Golden, CO. Each experimental setup consisted of foam devices composed of reticulated porous ceramic (RPC). The RPC has a full ceria or iron aluminate body. It fabricated using the replica method and subjected to a two-step redox reaction, which iteratively separated a stream of CO2 into O2 and CO. Reactivity was evaluated using CO production per mass of the reactive material. The tubular furnace yielded a CO production of 6.41 mL/g at a reduction temperature of 1600°C, showcasing a higher CO production rate and total amount than those obtained from experiments conducted with solar simulators and solar furnace setups. For iron aluminate RPC, the productivity was measured as 3.57 mL/g using HFSF at a reduction temperature of 1450°C. These results are somewhat higher than those of the previous experiment at lower reduction temperatures of 1400°C–1500°C. Additionally, the production of CO in the case of ceria RPC was compared with the steady flow model simulation, which assumed chemical equilibrium at various levels of oxygen partial pressure during the reduction process. On the basis of these results, this study proposes a solar fuel system with an open receiver that uses a high-temperature heat transfer fluid.
Optimization of Panel Spacing, Tilt Angle and Azimuth Angle for Bifacial Panels With Fixed Land Acreage and Orientation for Several United States Locations
Authors: Satheesh Sabin , Venkat Sidhanth , Mulford Rydge B.
Published: September 2024

Bifacial solar photovoltaic modules generate electrical power on both sides of the panel, increasing energy output. Through more effective utilization of installed surface area, bifacial panels surpass the energy generation of monofacial panels per unit installed acreage. The performance of bifacial panels largely depends on their positioning relative to the sun. Therefore, bifacial panels require specific orientations to maximize energy production. The specific challenges of bifacial modules has sparked research into the ideal spacing and orientation of bifacial panels, considering geographic location, tilt angles, and solar energy production. The present study aims to pinpoint the most favorable tilt angles, azimuth angles and panel row spacings for bifacial panels across various latitudes for a fixed array area and an adjustable array area. The core objective of this research is to maximize the electricity generated by bifacial solar panels. This involves creating a model that predicts power output for a specific location, accounting for variables like panel spacing, azimuth angle, average cell temperature, local ground reflection, and panel efficiency. The study also seeks to employ optimization to achieve peak annual power production. Methodologically, the study stratifies the solar panel array into zones, calculating the power generation capacity for a central panel in each zone. This includes factors like cell temperature, efficiency, and irradiance levels on both sides. Such calculations leverage Python APIs and packages for efficiency and accuracy. The computational model also factors in shadow effects, albedo, panel placement, and atmospheric conditions. The results reveal that an optimal power production exists for the bifacial panels with an associated optimal tilt angle, azimuth angle and panel spacing. These results are presented for a fixed array size and orientation, where the number of panels adjusts as the azimuth is varied as well as for a fixed number of panels. For New Jersey, the power output is maximized with a spacing of 2.5 meters between panels set at a 33-degree tilt and facing an azimuth of 176 degrees. Similar results are presented for a variety of locations in the United States of America. In summary, for solar farms to use land efficiently while maximizing energy generation, it is critical to consider all influencing factors — such as spacing, tilt, azimuth, and panel efficiency — comprehensively.
A Techno-Economic Analysis of a 50MWth Light-Trapping Cavity-Planar Solar Receiver Tower Capital Expenditures and its Cost Mitigation Strategies
Authors: Farias Mathew , Ma Zhiwen , Martinek Janna , Xu Ben
Published: September 2024

To maximize thermal efficiency, the National Renewable Energy Laboratory (NREL) has proposed a light-trapping cavity-planar receiver design intended to capture energy from reradiating surfaces. This system implements a macroscale light trapping mechanism induced by panels with triangular channels, this mechanism allows for elevated temperatures on the receiver panels and in turn the temperature of the HTF; using this design coupled with the implementation of a fluidized particle flow as the HTF, it can be expected for some components to reach a peak working temperature of nearly 1000°C cyclically throughout each day-night cycle. While these temperatures correlate to higher efficiency of the CSP tower they also demand intense thermomechanical properties from the materials used to make the receiver panels. In this analysis, we will list our assumptions to provide clarity on the significance of our calculation. This cost analysis will be conducted using a combination of both case study data and surveying industry to determine costs that are relevant to the current market trends. This analysis represents an early attempt to establish the Capital Expenditures required for a CSP tower of such design to determine the feasibility of implementing such a system in the industry.
Probing Thermal Transport in Fluidized Bed Using Modulated Photothermal Radiometry
Authors: Zhang Xintong , Adapa Sarath , Ma Zhiwen , Chen Renkun
Published: September 2024

In concentrated solar power (CSP) applications, fluidized bed is a promising approach for high heat transfer coefficient (HTC) solar receivers and heat exchangers. However, the complexity of multiphase mixing has made it difficult to characterize and analyze the heat transfer mechanism. This paper presents an experimental study on simultaneously characterizing heat transfer in both the near-wall and the bulk regions of a fluidized bed using modulated photothermal radiometry (MPR). The MPR is a non-contact frequency-domain technique using an intensity-modulated laser as the heat source and surface infrared emission as thermometry. The thermal penetration depth of the laser heating is varied by controlling its modulation frequency, and thus the measurement can resolve the near-wall and the bulk thermal resistances. With the MPR technique, we measured fluidized silica sands with a mean size of 164 μm in a vertical channel of 6 mm depth. Our results show that the near-wall thermal resistance is substantially increased with increasing gas velocity, which partially offsets the benefit of higher HTC brought by stronger particle mixing during the fluidization. We also used the MPR to quantify the improvement in particle-wall heat transfer in an inclined channel. We found that an 8° inclination towards the heat exchanging side led to a lower near-wall thermal resistance and a higher HTC at high gas velocities. This work demonstrates that the MPR technique is a useful tool to quantify the important near-wall thermal resistance from a bulk particle bed, which not only advances our understanding of heat transfer in fluidized beds, but may also contribute to the design of fluidized bed heat exchangers with higher HTC.
A Reinforcement Learning-Based Hierarchical Speed Control of an Infinitely Variable Transmission for Tidal Current Energy Converters
Authors: Qin Zhichang , Li Gang , Zhu Weidong
Published: September 2024

A tidal current energy converter (TCEC) is a device specifically designed to harness the kinetic energy present in tidal energy and convert it into stable mechanical rotational energy, which can then be used to generate electricity. The core component of the TCEC is an infinitely variable transmission (IVT), which adjusts the speed ratio to maintain a stable output speed regardless of the input speed changes caused by tidal changes. In order to ensure the efficient driving performance of the IVT system, a closed-loop control strategy based on IVT state measurement data is studied in this paper. This method can effectively track the expected output speed of the IVT system in general TCEC. Based on the proposed speed control strategy, the speed regulation of the whole IVT system under different conditions is studied in theory and simulation. These promising results could directly contribute to future research to improve the efficiency of tidal energy harvesting.
Thermal Energy Storage Conceptual Design Using Reclaimed Minerals As Heat Storage Material
Authors: Singh Ajit , Baghaei Lakeh Reza
Published: September 2024

Thermal energy storage (TES) plays a crucial role in energy sustainability, enabling the efficient storage and utilization of thermal energy from various sources. In this paper, we propose a novel TES system that utilizes reclaimed minerals as the heat storage medium. The system comprises a tightly packed bed of processed minerals enclosing a circular pathway for heat transfer fluid (HTF). To achieve optimal performance, we develop a computational method and algorithm to estimate the required pipe length for efficient charge and discharge cycles. The analysis encompasses various factors, including pipe length, storage material thickness, tube material, schedule, and contact resistance. Through a systematic examination of these parameters, we propose an algorithmic design for an effective pipe length tailored to the specific requirements of diverse applications in heat storage systems. A significant aspect of the proposed system is its adaptability. The system parameters, such as the temperature and mass flow rate of the HTF, can be modified based on the established effective length of the pipe. This adaptability contributes not only to increased cost-effectiveness but also to diminished energy loss in the overall energy storage system.

This research employs Computational Fluid Dynamics (CFD) modeling to simulate charge and discharge cycles, incorporating varying scenarios of pipe lengths and system parameters. By evaluating the exit temperatures of the HTF and the average temperature of the storage material at different stages, the study identifies a suitable pipe length that ensures adequate discharge time for the storage material once the cutoff temperature is achieved. This tailored approach aligns with the specific demands of diverse applications, ranging from solar power plants to industrial processes, showcasing the versatility and practicality of the proposed methodology.
Resistive Heating Catalytic Micro-Reactor Design for Process Intensified Fuel Reforming to Hydrogen
Authors: Burra Kiran Raj Goud , Sahin Murat , Gupta Ashwani
Published: September 2024

For the increasing demand for fuel flexibility in H2 production for fuel cells, the process intensification of fuel reforming using micro-reactors has become crucial. While prior literature has seen substantial progress in hydrocarbon fuel reforming within micro-reactors employing micro-channels, the supply of thermal energy for these endothermic reactions has faced limitations, relying on external heating, or operating in autothermal mode through partial combustion. This paper explores a novel approach by investigating the use of a thin-film catalytic heater for the development of micro-reactors. The study specifically focuses on dry methane reforming, showcasing a simplified micro-reactor where thermal energy is supplied through electric resistive heating of a thin carbon sheet with a catalyst applied to its surface. The thin catalytic heated layer resides inside the reactor, minimizing energy losses and significantly reducing the overall reactor footprint. Power input was varied from 90 W to 225 W to understand its impact on the temperature achieved inside the reactor, extent of CH4 conversion, H2 and CO yields. Fast thermal response times were achieved due to the use of carbon paper as thin film for heating. Ni/MgO impregnated onto the carbon paper was utilized as the catalytic heating element which resulted in CH4 conversions greater than 60% at temperature greater than 750 K. Influence of operating conditions such as the input molar ratio of CO2/CH4, and gas hourly space velocity (GHSV) were also investigated to understand the scope of the catalyst in this setup. High GHSVs (592,885 and 948,617 mL/(hr.gcatalyst)) were tested to understand the extent of throughput achievable using this setup. This approach demonstrates improved scope and feasibility for further intensification compared to conventionally heated microreactors. The research paves the way for more efficient and compact micro-reactors, addressing challenges associated with thermal energy supply in the context of fuel reforming processes.
A Data-Driven Surrogate Modeling Optimization Framework for the Economic Dispatch of Microturbines Using Hydrogen Blends
Authors: Thierry David , Supekar Sarang , Bhattacharya Chandrachur , Christopher Joshua , Biruduganti Munidhar , Dasgupta Debolina , Som Sibendu
Published: September 2024

The buildings and industrial sectors require reliable energy supply, while simultaneously mitigating greenhouse gas (GHG) emissions. This poses interesting opportunities for the use of microturbine technology for on-site energy generation using natural gas blended with electrolytic hydrogen (H2) from renewable electricity. Previous work has identified a commercial gas micro-turbine that can adopt a range of H2-Natural gas (NG) blends. In this paper, we present an economic dispatch framework for a Capstone C65 microturbine, that can deliver up to 65 kW of power using various H2-NG fuel blends to optimize for system operating costs of meeting demand for electricity in a given application. To optimize the system, multi-fidelity data obtained from a combination of experimental data and computational fluid dynamics simulations were used to create surrogate models through Gaussian Process Regressions (GPRs). Then, these models were embedded into a nonlinear optimization problem whereby the least-cost turbine dispatch strategy for a 24-hour period that meets a small commercial building power demand was found by choosing the H2-NG blends and electricity generation for multiple concurrent units while also considering purchasing electricity from the grid. Furthermore, we discuss the effects of a price on CO2 emissions on the optimal fuel blend and on-site electric generation.
Towards Improving High Spatiotemporal Weather Forecast Accuracy With Data-Driven Modeling
Authors: Sharma Shivesh , Najian Maede , Goudarzi Navid
Published: September 2024

This study explores the potential of mesoscale weather forecasting models, such as WRF output, characterized by high spatiotemporal resolution, to enhance the precision of initial and boundary conditions for microscale simulation model development, particularly computational fluid dynamics (CFD) models. Conventional numerical weather prediction methods face challenges in maintaining accuracy and managing escalating computational costs, particularly in proximity to urban boundaries. To address these challenges, this paper proposes a fusion of model reduction techniques and machine learning-based methods, including Artificial Neural Networks (ANN) and Recurrent Neural Networks (RNN). The research illustrates that complex flow field patterns can be effectively identified using ANNs and RNNs. Moreover, it introduces a Reduced-Order Model (ROM) as a promising approach to generating low-dimensional surrogate models having high accuracy and computational efficiency. The presented ROM algorithms, leveraging RNNs and ANNs, are modeled specifically for higher spatiotemporal resolution simulations, highlighting their capability to maintain accuracy compared to reference solutions.
Discrete Modeling of Flow and Heat Transfer in High-Temperature Gravity-Driven Granular Flows for Thermal Energy Storage
Authors: Mishra Ashreet , Abourazzouk Ouidad , Zhao Jian , Li Like
Published: September 2024

Gravity-driven dense granular flow can be a suitable heat transfer fluid (HTF) for high-temperature thermal and thermochemical energy storage (TES and TCES). Compared to analytical and continuum approaches, discrete element method (DEM) based modeling of granular flows can elucidate the particle-scale flow and thermal transport and is thus an attractive alternative approach. The particle-scale mechanical and flow properties such as sliding and rolling friction coefficients and restitution coefficient between particles are key input parameters for DEM simulations and they can vary with temperature. This study develops a DEM model to observe the particle flow and heat transfer characteristics of dense granular flows over a wide range of temperatures (from room temperature up to 800°C). The DEM flow and heat transfer model is validated and then further used to study the effects of particle flow properties on the local particle flow velocity and temperature profiles. Compared to room temperature (23°C) operation, the particle velocity decreases by 57.10% at the particle outlet for the case with an inlet particle temperature Tp,in = 800°C, 31.06% for Tp,in = 600°C, 16.39% for Tp,in = 400°C, and 6.14% for Tp,in = 200°C, showing the significant effect of high temperature operation. The observed inlet and outlet temperature differences are 0.0°C, 3.0°C, 13.9°C, 38.9°C, and 83.4°C for the cases with Tp,in = 23°C, 200°C, 400°C, 600°C, and 800°C, respectively. This work provides particle-scale insights into thermal transport behavior in granular flows, which are useful for designing novel particle-based heat exchangers and solar receivers and reactors.