bluuebunny/crossref_metadata_2025 huggingface dataset:
Transitioning drivers from linear to circular economic models: evidence of entrepreneurship in emerging nations
Authors: Beheshti Moein , Amoozad Mahdiraji Hannan , Rocha-Lona Luis
Published: September 2023

Purpose

Various publications have extensively documented the advantages of a circular economy in ensuring sustainability and limiting climate change. Despite academic records emphasising the need to adopt this business strategy, entrepreneurs in developing countries prefer linear economies. This reluctance is attributable to several factors, including insufficient infrastructure and technology, limited financial access, inadequate education systems and the prevalence of informal enterprises. Therefore, a thorough analysis of the underlying economic, political and social conditions is required to identify the drivers of circular economies (CEs) and their contribution to entrepreneurship in developing countries.

Design/methodology/approach

In this study, the authors first conducted a comprehensive quantitative literature review based on LangChain to identify the critical CE drivers from the social, technological and organisational perspectives. Based on the input from the expert panel of Iranian academic and industry professionals, the authors applied an integrated fuzzy interpretive structural modelling and cross-impact matrix multiplication approach to classification (Fuzzy-ISM-MICMAC) to investigate the chronology of entrepreneurial drivers.

Findings

Level-based model results reveal entrepreneurial drivers in developing nations and their interrelationships, specifically underlining the importance of supply chain factors and stakeholder preferences. Thus, the differences between the perception of the main drivers in developed and developing economies can be identified, with the former paying particular attention to legislative and financial factors. The study's findings contribute to conserving resources, reducing waste and adopting more sustainable corporate practices, thereby assisting developing countries in achieving development goals.

Originality/value

This study employs an innovative quantitative systematic literature review approach that relies on a large language model to identify the drivers of the CE. Furthermore, it adopts a systematic approach to examine the enablers of the CE rather than a narrow and individual perspective of the entrepreneurial drivers. The study employs the fuzzy ISM MICMAC technique to showcase the prioritisation of entrepreneurial prospects in emerging economies.
The effect of natural resources rents on human development in selected African countries
Authors: Debonheur Kadagde Dalam , Avom Désiré , Ouedraogo Idrissa
Published: September 2023

This research analyses the effects of natural resource rents on human development in selected African countries. It focuses on a panel of 41 countries and covers the period 1996–2019. We used the ordinary least squares, quantile regression, and the two‐step system generalized method of moments (GMM) estimates. The results show that total natural resource rents have a negative effect on human development. However, this negative effect is mitigated by food imports, which ensure food security for the countries concerned. Furthermore, taken individually, the effect of natural resource rents on human development is differentiated according to their type: forestry and natural gas rents have a positive effect on human development while, oil and coal rents have a negative effect. After controlling for per capita income and other macroeconomic, institutional, and environmental factors, these results are robust. The results suggest better management of natural resource rents, economic diversification and industrial development, environmental protection, food security, and the investment of the natural resources rents in human capital development to ensure long‐term human development in the region.
Effects of tail nerve electrical stimulation on the activation and plasticity of the lumbar locomotor circuits and the prevention of skeletal muscle atrophy after spinal cord transection in rats
Authors: Liu Jia‐Lin , Chen Zheng‐Hong , Wu Rong‐Jie , Yu Hai‐Yang , Yang Shang‐Bin , Xu Jing , Wu Chuang‐Ran , Guo Yi‐Nan , Hua Nan , Zeng Xiang , Ma Yuan‐Huan , Li Ge , Zhang Ling , Chen Yuan‐Feng , Zeng Yuan‐Shan , Ding Ying , Lai Bi‐Qin
Published: September 2023

Introduction

Severe spinal cord injury results in the loss of neurons in the relatively intact spinal cord below the injury area and skeletal muscle atrophy in the paralyzed limbs. These pathological processes are significant obstacles for motor function reconstruction.

Objective

We performed tail nerve electrical stimulation (TNES) to activate the motor neural circuits below the injury site of the spinal cord to elucidate the regulatory mechanisms of the excitatory afferent neurons in promoting the reconstruction of locomotor function.

Methods

Eight days after T10 spinal cord transection in rats, TNES was performed for 7 weeks. Behavioral scores were assessed weekly. Electrophysiological tests and double retrograde tracings were performed at week 8.

Results

After 7 weeks of TNES treatment, there was restoration in innervation, the number of stem cells, and mitochondrial metabolism in the rats' hindlimb muscles. Double retrograde tracings of the tail nerve and sciatic nerve further confirmed the presence of synaptic connections between the tail nerve and central pattern generator (CPG) neurons in the lumbar spinal cord, as well as motor neurons innervating the hindlimb muscles.

Conclusion

The mechanisms of TNES induced by the stimulation of primary afferent nerve fibers involves efficient activation of the motor neural circuits in the lumbosacral segment, alterations of synaptic plasticity, and the improvement of muscle and nerve regeneration, which provides the structural and functional foundation for the future use of cutting‐edge biological treatment strategies to restore voluntary movement of paralyzed hindlimbs.
Combination of fMRI and PET reveals the beneficial effect of three‐phase enriched environment on post‐stroke memory deficits by enhancing plasticity of brain connectivity between hippocampus and peri‐hippocampal cortex
Authors: Lu Yun , Li Mingcong , Zhuang Yuming , Lin Ziyue , Nie Binbin , Lei Jianfeng , Zhao Yuanyuan , Zhao Hui
Published: September 2023

Aim

The three‐phase enriched environment (EE) intervention paradigm has been shown to improve learning and memory function after cerebral ischemia, but the neuronal mechanisms are still unclear. This study aimed to investigate the hippocampal–cortical connectivity and the metabolic interactions between neurons and astrocytes to elucidate the underlying mechanisms of EE‐induced memory improvement after stroke.

Methods

Rats were subjected to permanent middle cerebral artery occlusion (pMCAO) or sham surgery and housed in standard environment or EE for 30 days. Memory function was examined by Morris water maze (MWM) test. Magnetic resonance imaging (MRI) was conducted to detect the structural and functional changes. [18F]‐fluorodeoxyglucose (FDG) positron emission tomography (PET) was conducted to detect brain energy metabolism. PET‐based brain connectivity and network analysis was performed to study the changes of hippocampal–cortical connectivity. Astrocyte‐neuron metabolic coupling, including gap junction protein connexin 43 (Cx43), glucose transporters (GLUTs), and monocarboxylate transporters (MCTs), was detected by histological studies.

Results

Our results showed EE promoted memory function improvement, protected structure integrity, and benefited energy metabolism after stroke. More importantly, EE intervention significantly increased functional connectivity between the hippocampus and peri‐hippocampal cortical regions, and specifically regulated the level of Cx43, GLUTs and MCTs in the hippocampus and cortex.

Conclusions

Our results revealed the three‐phase enriched environment paradigm enhanced hippocampal–cortical connectivity plasticity and ameliorated post‐stroke memory deficits. These findings might provide some new clues for the development of EE and thus facilitate the clinical transformation of EE.
Subjectively preferred octave size is resolved at the late stages of cerebral auditory processing
Authors: Jaatinen Jussi , Väntänen Jani , Salmela Viljami , Alho Kimmo
Published: September 2023

Human listeners prefer octave intervals slightly above the exact 2:1 frequency ratio. To study the neural underpinnings of this subjective preference, called the octave enlargement phenomenon, we compared neural responses between exact, slightly enlarged, oversized, and compressed octaves (or their multiples). The first experiment (n = 20) focused on the N1 and P2 event‐related potentials (ERPs) elicited in EEG 50–250 ms after the second tone onset during passive listening of one‐octave intervals. In the second experiment (n = 20) applying four‐octave intervals, musician participants actively rated the different octave types as ‘low’, ‘good’ and ‘high’. The preferred slightly enlarged octave was individually determined prior to the second experiment. In both experiments, N1‐P2 peak‐to‐peak amplitudes attenuated for the exact and slightly enlarged octave intervals compared with compressed and oversized intervals, suggesting overlapping neural representations of tones an octave (or its multiples) apart. While there were no differences between the N1‐P2 amplitudes to the exact and preferred enlarged octaves, ERP amplitudes differed after 500 ms from onset of the second tone of the pair. In the multivariate pattern analysis (MVPA) of the second experiment, the different octave types were distinguishable (spatial classification across electroencephalography [EEG] channels) 200 ms after second tone onset. Temporal classification within channels suggested two separate discrimination processes peaking around 300 and 700 ms. These findings appear to be related to active listening, as no multivariate results were found in the first, passive listening experiment. The present results suggest that the subjectively preferred octave size is resolved at the late stages of auditory processing.
Complementarity analysis of a multi‐item inventory model with leading product pricing
Authors: Kim Sangjo , Feng Youyi , Xu Jianjun
Published: September 2023

Our research investigates a joint inventory replenishment and pricing problem, where a seller controls the price of a leading product while restocking for all the products. We demonstrate that the seller's expected value functions present an [Formula: see text] structure, recommending an optimal order‐up‐to inventory‐level and list‐price policy. Our findings reveal divergent economic relationships between products from the seller's and customer's perspectives, suggesting managers broaden their strategies beyond customer viewpoints. We extend the pricing and inventory analysis to scenarios involving three substitute products under both price and inventory control. In these situations, we further reveal that sellers and customers uniformly view product inventories as substitutes, and the corresponding value functions are submodular and mutually diagonally dominant.
Predicting suicidal ideation in psychiatrically hospitalized veterans using the death/suicide Implicit Association Test: A prospective cohort study
Authors: Smith Eric G. , Howard Alexandra , Schultz Mark , Li Mingfei , Salvatore Paola , O'Shea Brian A.
Published: September 2023

Introduction

We investigated whether the Death/Suicide Implicit Association Test (D/S‐IAT) predicted suicidal ideation (SI) in psychiatric inpatients.

Methods

One hundred eighty veterans admitted for either SI or suicidal behavior (SB) (the primary sample) (N = 90) or alcohol detoxification (N = 90) completed the D/S‐IAT and scales measuring SI. Correlation and regression coefficients were measured between the D/S‐IAT (as a full‐scale or dichotomized score [D > 0]) and self‐reported current or imminent SI (over the next 1–3 days).

Results

In the primary sample, the full‐scale D/S‐IAT was significantly correlated with the intensity of current SI (r = 0.22, p = 0.04) and especially with wishes to be dead (r = 0.35, p < 0.001). The intensity of imminent SI was significantly predicted by the full‐scale (p = 0.02) and dichotomized D/S‐IAT score (p = 0.05) in a multiple regression model. However, no significant associations were observed when both the D/S‐IAT score and current (present/absent) or imminent SI (occurred/did not occur) were dichotomous measures. In participants receiving alcohol detoxification, the D/S‐IAT significantly predicted only wishes to be dead (r = 0.33, p < 0.001).

Conclusion

The full‐scale D/S‐IAT score predicted the current intensity of wishes to be dead in both inpatient samples, and current and imminent SI in participants admitted for SI/SB. The dichotomized D/S‐IAT score did not predict the simple occurrence of SI.
Must religious nationalism divide? Race, government‐supported religion, and views of political solidarity and compromise
Authors: Perry Samuel L. , McDaniel Eric L.
Published: September 2023

Background

Americans who believe government policies should bolster religion's influence tend to favor rigid in‐group/out‐group distinctions and hierarchies. Yet given that religious and political views are fundamentally racialized, we theorize racial identity moderates the link between favoring government‐supported religion and views toward political solidarity and compromise.

Objective

This study extends our understanding of how beliefs about religion and politics involve not only different, but contradictory orientations to political solidarity and compromise contingent on racial identity.

Methods

We estimate binary logistic regression models using data from Pew Research Center's American Trends Panel, Wave 92, a nationally representative survey of over 9200 Americans.

Results

Main effects indicate that favoring government‐supported religion is associated with rejecting political compromise, but unassociated with measures of solidarity. Interactions, however, show main‐effects mask considerable racial variation. Substantively, the link between favoring government‐supported religion and rejecting political compromise is limited to White Americans. Yet Black Americans who favor government‐supported religion become significantly more likely to recognize shared values despite political differences and Black Americans who favor government‐supported religion see less difference between Democrats and Republicans, while their White counterparts see more.

Conclusions

Favorability toward government policies supporting religion does not necessarily represent “us versus them” orientations. Rather, the association is racially contingent.
Successful total hip arthroplasty in a miniature horse
Authors: Cullen Matthew D. , Pettitt Rob A. , Tomlinson Andrew W. , Louro Luis F. , Bennell Alison J. , Michael Robert , Stack John D.
Published: September 2023

Objective

To describe the surgical treatment, postoperative management, and outcome of a miniature horse undergoing total hip arthroplasty (THA).

Study design

Case report.

Animals

A 4‐year‐old miniature horse stallion weighing 85 kg.

Methods

The horse presented with left coxofemoral luxation of ~6 weeks duration. Computed tomography confirmed craniodorsal luxation with marked degenerative changes to the femoral head. The horse underwent THA using cementless press fit implants, including an interlocking lateral bolt for the femoral stem.

Results

The horse recovered well from anesthesia but suffered a coma‐like episode after returning to a stable. Following treatment of presumed hypovolemia, the horse regained normal mentation and was discharged 24 days after surgery. At reassessment 12 weeks postoperatively, the horse was 2/10 left hind limb lameness at trot with good healing of the surgery site. Five months postoperatively mild (1/10) lameness remained at trot but the horse was able to canter normally on both reins. The horse has since been managed normally with no veterinary treatment required for 32 months postoperatively.

Conclusion

Total hip arthroplasty is possible in miniature horses weighing up to 85 kg and can result in a good long‐term outcome.
Opiniões de estudantes de graduação em Enfermagem sobre condições de trabalho
Authors: Ferreira Aydogdu Ana Luiza
Published: September 2023

Introdução: A condição de trabalho dos profissionais de enfermagem é um tema amplamente discutido, pois aborda assuntos como carga horária e salários, desenvolvimento profissional e plano de carreira, saúde e segurança ocupacional, condições físicas adequadas e equipamentos suficientes, trabalho em equipe e reconhecimento profissional, e gestão e liderança, que por sua vez influenciam na satisfação profissional e na qualidade da assistência. Fatores relacionados às condições de trabalho afetam também as opiniões de estudantes de enfermagem com relação à profissão, podendo gerar dúvidas e preocupações a respeito do futuro quando enfermeiros. Objetivo: Conhecer as opiniões de estudantes de graduação em enfermagem que estudam em universidades brasileiras a respeito das condições de trabalho da enfermagem no Brasil. Método: Trata-se de uma pesquisa descritiva, com abordagem qualitativa. Um total de 25 narrativas de estudantes de enfermagem fazem parte do estudo. Resultados: Quatro temas foram identificados: 1) condições de trabalho da enfermagem; 2) fatores que ajudam a superar as condições de trabalho adversas; 3) reflexões sobre o futuro na profissão; 4) sugestões para melhorar as condições de trabalho da enfermagem. Conclusão: O apoio de administradores públicos e também o suporte institucional e de líderes de enfermagem foram apontados como fatores importantes para melhorar as condições no ambiente de trabalho da enfermagem. Com a melhora das condições de trabalho dos enfermeiros, estudantes de enfermagem também se sentirão mais motivados a se dedicarem ao curso e seguirem carreira na profissão.
Comment on the Paper “Duel Solutions in Hiemenz Flow of an Electro-Conductive Viscous Nanofluid Containing Elliptic Single-/Multi-Wall Carbon Nanotubes With Magnetic Induction Effects” (Ferdows, M., Tahia, T., Bég, O. A., and Bég, T. A., 2022, ASME Open J. Eng., 1, p. 011040)
Authors: Pantokratoras Asterios
Published: September 2023

Some serious errors exist in the above paper.
Benchtop Characterization of Wearable Respiratory Monitors for Assessing Feasibility of Measuring Lung Volume
Authors: Jayasekera Shehan , Hensel Edward C. , Robinson Risa J.
Published: September 2023

Objective: This study characterizes three commercially available wearable respiratory monitors (WRMs): (1) Hexoskin Smart Garment, (2) Smartex WWS, and (3) Equivital EQ02 LifeMonitor, each with a unique chest motion sensor technology: respiratory inductance plethysmography, piezoresistor, and strain gauge, respectively. WRMs comprise of a body garment with embedded sensors that measure ambulatory chest motion in real-time. Once calibrated, chest motion waveforms from WRMs can be converted to lung volume waveform, which is then used to derive respiratory topography. The aim of this study is to assess and compare these WRMs in terms of: (i) their response signal to chest motion linearity, which is necessary for successful calibration, and (ii) their ability to measure breath-hold, which is a parameter of interest for lung deposition modeling. Methods: A benchtop test setup was built to simulate chest motion in a controlled way to facilitate comparison across the three devices. A staircase square-wave chest motion profile was used to simultaneously assess both signal linearity and ability to measure breath-hold. The respiratory response from the sensors was compared to the simulated chest motion. Results: The Hexoskin showed the best performance in both metrics, whereas the Equivital had the worst performance in both. The Smartex showed moderate ability to measure breath-hold but poor signal linearity. Conclusion: Of the three WRMs tested, the Hexoskin appears to be the best choice for ambulatory lung volume measurement. Significance: This study demonstrates the feasibility of adapting current technology to observe respiratory behavior valuable in many research domains, including tobacco research.
Cellular Inorganic Ceramic for Highly Efficient Daytime Passive Radiative Cooling
Authors: Lin Kaixin , Zhu Yihao , Ho Tsz Chung , Tso Chi Yan
Published: September 2023

Traditional compression-based cooling systems consume great amounts of energy, causing adverse impacts on the environment by releasing heat and ozone-depleting pollutants. Daytime passive radiative cooling is regarded as an eco-friendly alternative to generate cooling without electricity and coolants. In order to achieve continuous and effective cooling, the cooler requires high solar reflection as well as strong mid infrared emission. However, it remains a great challenge to realize cooling effect in the daytime. Sunlight is an intensive heat source in the daytime, especially during noontime. Under sunlight, even absorption of a few percent of solar irradiation can easily compensate for the thermal heat dissipated by thermal radiation, and therefore fail to achieve any cooling effect. Here we develop a cellular inorganic radiative cooler in the format of ceramic, which possesses advanced optical properties for radiation cooling while exhibiting great outdoor applicability. The cellular ceramic possesses a hierarchically porous structure, which results in efficient light scattering across the whole solar spectrum. The average solar reflection of the cellular ceramic reached a recorded-high of 99.6% with porosity of 70% and thickness of around 600 μm. With the near-ideal solar reflection and high thermal emission (96%), the cellular ceramic can theoretically obtain cooling power in excess of 140 W/m2 under 1000 W/m2 solar intensity in favorable application conditions. Moreover, the high bond strength and chemical inertness of alumina protect the cellular ceramic from the adverse effect of UV exposure, which is desired for long-term outdoor applications. The outstanding performance of cellular ceramic surpasses that of current daytime radiative coolers. The facile fabrication and promising applicability of cellular ceramic exhibits great potential for large-scale applications, such as buildings, to saving the energy for indoor thermal regulation.
Hydrogel-Coated Mesh for High-Efficiency, Ultra-Fast Oil-Water Separation
Authors: Williams Amanda , Zhou Shuqi , Xu Ben , Hu Han
Published: September 2023

Fast and efficient oil-water separation is critical to resolving industrial wastewater, environmental protection, and oil spills. With the demand for oil continuing to grow and the global oil reserves being limited in supply, it becomes more important to be able to recover as much oil as possible. In this paper, a reinforced membrane made using a polyacrylamide (PAM) hydrogel solution was used to coat different copper mesh samples that have a variety of pore sizes. The wetting properties of membranes are characterized by the contact angle (CA) measurements, the permeability of bulk fluids, and the surface morphologies of the mesh before and after coating. Using a contact angle goniometer, it was found that the static underwater oil CA showed to be over 90° while the oil CA in air resulted in an angle below 15°. Since the oil CA in the air is less than the oil CA underwater, we can imply that the PAM hydrogel-coated mesh samples are superhydrophilic in the method of using an air-solid-liquid three-phase system. As the mesh pore size increases, the oil CA also increases. The difference in weight during the swelling period becomes larger with increasing mesh pore size up to approximately 2880 minutes. With the use of a long working distance microscope, it was found a uniform hydrogel coating resulted in smaller pore size and a rougher surface. It was found that the coated mesh after testing has less binding at the mesh joints compared to the coated mesh before testing. From this, it can be indicated that high swelling rates result from large aggregation near the mesh joints.
Design Methodology of a Concentrating Solar Volumetric Receiver
Authors: Akba Tufan , Baker Derek , Mengüç M. Pınar
Published: September 2023

A volumetric receiver design process is proposed to respond wide range of power, outlet temperature, or mass flow rate needs. In the receiver model, concentrated solar radiation hits the inner surface cavity and heats the gaseous fluid passing through the porous media assembled between the cavity and the insulator. Porous media properties and receiver geometry are coupled in the design process to determine the best possible option. A two-step process starts with a parameter sweep to create a surrogate model. Then, gradient-based design optimization is performed using two different surrogate models to maximize the outlet air temperature for bounded design variables in receiver volume and outer surface temperature constraints.

The proposed design process has the advantage of exploring more design options faster using the surrogate model and more accurate results using the base model in the plant-level simulations. The methodology is discussed by comparing the surrogate models and the model validation shows that over 95% accuracy is obtained using both surrogate models. Surrogate-based design optimization is compared as in solution time and the final results are compared with respect to the base receiver model.
Thermodynamic Performance Investigation of Environmentally Friendly Working Fluids in a Geothermal Integrated Pumped Thermal Energy Storage System
Authors: Mwesigye Aggrey
Published: September 2023

Among the available energy storage technologies, pumped thermal energy storage (PTES) is emerging as a potential solution for large-scale electrical energy storage with no geographical limitations and high roundtrip efficiencies. However, PTES requires a low-cost high temperature heat source to achieve reasonable roundtrip efficiencies. Moreover, organic Rankine cycle-based PTES systems require high performance and environmentally friendly working fluids. In this study, the thermodynamic performance of a geothermal integrated PTES system using environmentally friendly working fluids is investigated. The mathematical model of the geothermal integrated PTES system is developed using the first and second laws of thermodynamics and implemented in Engineering Equation Solver (EES). With the developed model, the thermodynamic performance of the PTES system for different working fluids, including Butene, cyclopentane, iso-butane, R1233zd(E), R1234ze(Z), R1224yd(Z), HFO1336-mzz(Z), R365mfc, n-hexane, and n-pentane was investigated. For geothermal fluid outlet temperatures between 60°C and 120°C and geothermal fluid inlet and outlet temperature differences across the evaporator between 20°C and 60°C, the net power ratio i.e., the ratio of the electrical energy discharged to the electrical energy used to run the charging cycle is between 0.25 and 1.40. This shows that the system has the potential to give back more than 100% of the electrical energy used during charging under certain conditions. High net power ratios are obtained for a combination of high source temperatures and low geothermal fluid inlet and outlet temperature differences.
Stability Assessment of High Temperature Coatings for Flux Measurement Applications
Authors: McLaughlin Luke P. , Laubscher Hendrik , Konings Jörgen
Published: September 2023

This study investigated the durability of four high temperature coatings for use as a Gardon gauge foil coating. Failure modes and effects analysis have identified Gardon gauge foil coating as a critical component for the development of a robust flux gauge for high intensity flux measurements. Degradation of coating optical properties and physical condition alters flux gauge sensitivity, resulting in flux measurement errors. In this paper, four coatings were exposed to solar and thermal cycles to simulate real-world aging. Solar simulator and box furnace facilities at the National Solar Thermal Test Facility (NSTTF) were utilized in separate test campaigns. Coating absorptance and emissivity properties were measured and combined into a figure of merit (FOM) to characterize the optical property stability of each coating, and physical coating degradation was assessed qualitatively using microscope images. Results suggest rapid high temperature cycling did not significantly impact coating optical properties and physical state. In contrast, prolonged exposure of coatings to high temperatures degraded coating optical properties and physical state. Coatings degraded after 1 hour of exposure at temperatures above 400 °C and stabilized after 6–24 hours of exposure. It is concluded that the combination of high temperatures and prolonged exposure provide the energy necessary to sustain coating surface reactions and alter optical and physical coating properties. Results also suggest flux gauge foil coatings could benefit from long duration high temperature curing (> 400 °C) prior to sensor calibration to stabilize coating properties and increase measurement reliability in high flux and high temperature applications.
Data Center Environmental Burden Reduction Through On-Site Renewable Power Generation
Authors: McMullen Matthew , Wemhoff Aaron P.
Published: September 2023

The energy demands from data centers contribute greatly to water scarcity footprint and carbon emissions. Understanding the use of on-site renewable power generation is an important step to gaining insight into making data centers more sustainable. This study examines the impact of on-site solar or wind energy on water scarcity usage effectiveness (WSUE) and carbon usage effectiveness (CUE) at a U.S. county scale for a given data center size, water consumption level, and energy efficiency. The analysis uncovers combinations of specific metrics associated with the grid-based carbon emissions and water scarcity footprint that enable predictions of the improvements anticipated when implementing on-site solar or wind energy. The implementation of on-site renewables has the most benefit on reducing carbon footprint in areas with high existing grid-based emissions such as the mountain regions and the western side of the Appalachian Mountains. The largest benefit in reducing water scarcity footprint is generally seen in the western U.S.
Simulation of the Performance of a High Temperature Solar Thermal Receiver Comprised Parallel Micro-Pin Unit-Cells Fabricated via Additive Manufacturing
Authors: Bahrami Leyli , Yurkovetsky Sophia M. , Rasouli Erfan , Narayanan Vinod , Fronk Brian M.
Published: September 2023

This paper aims to assess the receiver efficiency, maximum surface temperature, and pressure drop through a ∼10 MW thermal solar receiver designed to heat carbon dioxide from 550 to 720°C at 20 MPa. The solar receiver is comprised of 400 identical unit-cells fabricated using additive manufacturing. Each unit-cell contains an array of micro-pins with a single inlet and outlet for carbon dioxide. A unit-cell thermal hydraulic submodel developed in prior work is integrated into a multiple unit-cell receiver model, which solves for the mass flow rate, outlet temperature, maximum surface temperature, efficiency, pressure drop, and other parameters of each unit-cell and the overall receiver for a specified solar flux distribution. Simulations are conducted for a scenario in which the overall outlet temperature is fixed, and the pressure drop through each parallel unit cell is the same. The results suggest that overall receiver efficiency for the parallel unit-cell approach can be optimized using different unit-cell geometries throughout the receiver.
Controls and Operational Strategy for Gen 3 Particle Pilot Plant
Authors: Laubscher Hendrik Frederik , Maldonado Luis Garcia , Alvarez Francisco , McLaughlin Luke P. , Schroeder Nathan R. , Albrecht Kevin J. , Sment Jeremy N. I. , Plewe Kaden E.
Published: September 2023

A comprehensive control strategy is necessary to safely and effectively operate particle based concentrating solar power (CSP) technologies. Particle based CSP with thermal energy storage (TES) is an emerging technology with potential to decarbonize power and process heat applications. The high-temperature nature of particle based CSP technologies and daily solar transients present challenges for system control to prevent equipment damage and ensure operator safety. An operational controls strategy for a tower based particle CSP system during steady state and transient conditions with safety interlocks is described in this paper. Control of a solar heated particle recirculation loop, TES, and a supercritical carbon dioxide (sCO2) cooling loop designed to reject 1 MW of thermal power are considered and associated operational limitations and their influence on control strategy are discussed.
Construction of Short-Time Solutions in Heat Conduction
Authors: de Monte Filippo , Woodbury Keith A. , Najafi Hamidreza
Published: September 2023

The concept of both penetration and deviation times for rectangular coordinates along with the principle of superposition for linear problems allow short-time solutions to be constructed for a one-dimensional finite body from the well-known solution of a semi-infinite body. Some adequate physical considerations due to thermal symmetries with respect to the middle plane of a slab to simulate homogeneous boundary conditions of the first and second kinds are also needed. These solutions can be applied at the level of accuracy desired (one part in 10A, with A = 2, 3, ..., 15) with respect to the maximum temperature rise (that always occurs at the active surface and at the time of interest) in place of the exact analytical solution to the problem of interest.
Using Radiant Heating System to Prevent Bridge Freezing
Authors: Abaza Hussein , Shenawa Amaal , Semmelink Scott
Published: September 2023

Bridge freezing before roads is a major concern in cold climates as it is a major cause for road accidents. Several active systems were made to prevent bridge surface freezing. These systems include several automated and complex systems such as automatic anti-freeze spray, using phase change materials in the concrete bridge’s deck, and imbedding heating system in bridge’s decks. These systems are usually expensive to run and operate and some of these systems have negative impact on the environment.

This research investigates using radiant heaters for maintaining the concrete temperature within the required limits. Several passive and active methods are used to maintain concrete temperature above the that of the adjacent road. Radiant heaters provide direct, instantaneous, and uniform heating to the bridge surface.

The Infrared radiant heating method was tested using an environmental control chamber. Two concrete samples were placed in the climate chamber that simulates cold weather. Thermocouples were used to record the surface temperature, the middle of the concrete samples’ temperature and the bottom of the samples’ temperature. Infrared camera was also used to measure and verify the concrete surface temperatures. The data analysis showed that concrete surface temperature dropped quickly and become significantly lower than the ambient temperature in the absence of solar radiation. However, introducing radiant heating brings the concrete surface temperature and the core temperature of the concrete samples to the required temperature in a short period of time. A comparison between this research results and other research that investigated the performance of other freezing prevention methods showed that using radiant heating to prevent bridge freezing is effective, economical, and can be applied to existing bridges.
Experimental Performance of a Nonlinear Control Strategy to Regulate Temperature of a High Temperature Solar Reactor
Authors: Alsahlani Assaad , Ozalp Nesrin
Published: September 2023

Despite the significant potential of solar thermochemical process technology for storing solar energy as solid-state solar fuel, several challenges have made its industrial application difficult. It is important to note that solar energy has a transient nature that causes instability and reduces process efficiency. Therefore, it is crucial to implement a robust control system to regulate the process temperature and tackle the shortage of incoming solar energy during cloudy weather. In our previous works, different model-based control strategies were developed namely a Proportional Integral Derivative controller (PID) with gain scheduling and adaptive Model Predictive Control (MPC). These methods were tested numerically to regulate the temperature inside a high temperature tubular solar reactor. In this work, the proposed control strategies were experimentally tested under various operation conditions. The controllers were challenged to track different setpoints (500°C, 1000°C, and 1450°C) with different amounts of gas/particles flowrates. Additionally, the flow controller was tested to regulate the reactor temperature under a cloudy weather scenario. The ultimate goal was to produced 5 kg of reduced solar fuel magnesium manganese oxide (MgMn2O4) successfully, and the controllers were able to track the required process temperature and reject disturbances despite the system’s strong nonlinearity. The experimental results showed a maximum error in the temperature setpoint of less than 0.5% (6°C), and the MPC controller demonstrated superior performance in reducing the control effort and rejecting disturbances.
A 3D Heat Transfer Model of a Glass Additive Manufacturing Process
Authors: Jibben Zechariah , Raghavan Narendran , Bernardin John
Published: September 2023

Glass additive manufacturing is an emerging technology for the printing of complex glass structures. In one such system, a glass filament is fed onto a glass slide and heated by a laser to working temperatures. We present a 3D heat transfer model of this glass AM system (GLAMS), using the open source multi-physics modeling program Truchas. This model relies on a mimetic finite difference discretization of the heat conduction equation on static unstructured meshes. The effects of laser heat flux, thermal radiation, convection, and changing thermal contact in the system are incorporated via boundary conditions and internal interface conditions. Such modeling gives us insight into behavior that is difficult or impossible to measure in the laboratory, such as temperatures and thermal gradients interior to the glass. Results are shown for thermal gradients, heatup and cooldown times, steady-state temperatures, and a sensitivity analysis of the process. We analyze the melt region at steady-state, showing the dominant mode of heat transfer is thermal conductivity, while radiation and convection are relatively insignificant. The time needed to reach steady state under laser heating is found to scale linearly with laser power and spot size within the processing range. Results are also compared against experimental thermal camera readings of prints with soda lime and borosilicate glasses.
Thermal Buoyancy Effect on Wake-Induced Vibration of a Cylinder Submerged in the Wake of a Stationary Cylinder
Authors: Khan Hamid H. , Islam Md. , Janajreh Isam
Published: September 2023

This work numerically investigates the thermal buoyancy effect on the wake-induced vibration of a heated cylinder submerged in the wake of a stationary cylinder. Simulations are performed at Richardson number Ri = [0, 1], Prandtl number Pr = 7.1 and Reynolds number Re = 100. The downstream cylinder is elastically mounted in transverse direction with reduced velocity Ur = 4–20. The mass ratio is set to 2 and the damping coefficient is considered zero to attain maximum oscillation. The thermal buoyancy effect on wake-induced vibration is illustrated through flow structures, heat transfer and oscillation amplitude. Thermal buoyancy influences the flow around a cylinder and suppresses the oscillation amplitude. Multiple heated cylinders in close proximity may suffer fatigue failures or structural damage. The present findings could increase the structural durability of heated cylinders.
Heat Transfer Characteristics According to Inner Pipe in a Gas Turbine Vane Internal Passage
Authors: Heo Jeonghun , Lee Hee Jae , Kim Taehyun , Kim Gyeongryun , Lee Changyong , Cho Hyung Hee
Published: September 2023

The use of an inner pipe within internal passages of gas turbine vanes has been proposed as a solution to address the issue of secondary air supply to the vane hub. This study investigates the effect of the inner pipe on heat transfer of the internal passage. An experiment using the naphthalene sublimation method is performed to acquire local heat/mass transfer coefficients for Reynolds numbers of 20,000, 40,000, and 60,000. Two configurations of square channels are analyzed: base case and inner pipe case. The flow structure of the channel was also analyzed through a numerical simulation method. The presence of the pipe changes flow patterns by the regeneration of swirling flow motion and the expansion of vortices, increasing heat transfer. In the upstream region (x/Dh < 7.8), the heat transfer patterns are similar between the cases, despite a slight increase in values. However, in the downstream region (x/Dh>8), which includes the fully developed region of the channel flow, a tremendous increase in the heat transfer between the two cases is observed. Overall, the study concludes that the use of an inner pipe in internal passage of gas turbine vanes can enhance heat transfer on the surface.
Experimental Analysis of Single Evaporation Tube Utilizing Sintered Copper Particle Wicking Structures
Authors: Spitzenberger Jeremy , Hoelle James , Mohammed Ramy H. , Ismael Laith , Ma Hongbin , Wang Pengtao , Kowalski Stephen , Nawaz Kashif
Published: September 2023

Wicking structures have been widely used within passive heat transfer devices with high heat fluxes, such as heat pipes, to enhance their thermal performance. While wicking structures promote capillary pumping of the working fluid as well as thin film evaporation, they can result in capillary evaporation and further enhances the evaporation heat transfer. In this study, a 0.5 mm thick layer of 105 μm sintered copper particles was added to the inner wall of a copper tube, aiming to enhance the heat transfer characteristics by taking advantage of capillary evaporation. Acetone was chosen as the working fluid, and the performance of an evaporation tube was tested for power inputs of 10, 30, 50, and 70 W. For each power input, trials were run at inclination angle varying from −90° and 90° to investigate the capillary effects. The temperature measurements showed that the temperature distribution along the evaporation tube is always downward sloping, meaning the temperature at the fluid inlet is larger than the outlet. Interestingly, the surface temperature at some locations is less than the outlet temperature, indicating the effect of capillary evaporation. In addition, a theoretical investigation was performed to investigate the effects of the particle size on the thermal performance of the evaporation tube and found that particle sizes affect capillary evaporation.
Experimental Study on the Flow Boiling Heat Transfer in Horizontal Tubes With Composite Structure
Authors: Lin Yuhao , Wang Jacheng , Wang Xu , Li Wei , Sherif S. A.
Published: September 2023

To fill the research gap in the study of R410A flow boiling on composite surfaces, four heat exchange tubes with different structures were tested: an enhanced tube with herringbone teeth (EHT_HB), a tube with a dimple structure (EHT_DIM), a tube with a composite herringbone tooth/dimple (EHT_HB/DIM), and a smooth tube for comparison with a baseline. The experimental conditions were set as follows: saturation temperature 279K, mass flux range of 50–205 kg/(m2.s), and vapor quality 0.2–0.8. After confirming the validity of the experimental results, the effect of the mass flux on the flow boiling heat transfer and pressure drop characteristics were examined. Results showed that the flow boiling heat transfer coefficient and pressure drop increased with the increase of the mass flux and the vapor quality in the tested tubes. The EHT_HB/DIM tube was found to combine the advantages of the two structures to have the highest heat transfer coefficient. The average value was found to be 43.75% higher than that of the smooth tube. Meanwhile, the average flow boiling heat transfer coefficients of the EHT_HB tube and the EHT_DIM tube were found to be 1.15 and 1.35 times that of the smooth tube, respectively. From the perspective of frictional pressure drop, it was concluded that the EHT_HB/DIM tube exhibited the maximum frictional pressure drop. The optimum working conditions of the enhanced tubes were determined by introducing a performance factor that captures the combined effects of the heat transfer and pressure drop.
Effect of Inner Fin Tube Structure on Comprehensive Performance of Supercritical Carbon Dioxide and Lead Bismuth Eutectic Heat Exchanger
Authors: Liu Shuhan , Liu Ji'an , Liu Qingjiang , Lei Xianliang
Published: September 2023

In the combined system of lead cooled fast reactor (LFR) and supercritical carbon dioxide (S-CO2) Brayton cycle, the intermediate heat exchanger plays a key role in the whole power system. However, the existing heat exchanger can not meet the trend of miniaturization of lead cooled fast reactor. Considering the thermo-physical properties and heat transfer behaviors in both S-CO2 and liquid lead bismuth eutectic (LBE) are significantly different, an asymmetric compact coupled heat exchanger learning from Honeycomb structure is proposed. Through numerical simulation, it is found that the thermal resistance mainly exists in the cold side. In order to enhance the heat transfer at the S-CO2 side, the fin tube is adopted at the cold side. The results show that the heat transfer performance and friction factor of the heat exchanger increase with the increase of fin height, width and number of fins due to the increase of heat transfer area. When the fin height is increased, PEC gradually increases at low inlet velocity, and then decreases at high inlet velocity; When the fin width is increased, PEC increases first and then decreases at low inlet velocity, and decreases gradually at high inlet velocity; With the increase of the number of fins, PEC showed an increasing trend at different inlet velocities.
Improving the Accuracy of Experimentally Inferred Heat Transfer Coefficients for Hot Stamping
Authors: Singh Arpan Raj , Butcher Cliff , Daun Kyle J.
Published: September 2023

Hot stamping of ultra-high strength automotive parts requires accurate knowledge of the heat transfer coefficient (HTC) between the blank and tool, since this parameter governs the quenching rate, which, in turn, determines the strength and hardness of the formed part. Inverse heat conduction analysis of subsurface temperature measurements within the die, coupled with temperature measurements made on the blank, appears to be an effective way to infer the HTC, but the ill-posed aspect of this inverse problem sensitizes the HTC to small experimental artifacts. This paper examines how thermocouple installation in the blank and the die can bias the inferred HTC, and suggests techniques that may be used to obtain a reliable HTC estimate.
Prosodic cues to word boundaries in a segmentation task assessed using reverse correlation
Authors: Osses Alejandro , Spinelli Elsa , Meunier Fanny , Gaudrain Etienne , Varnet Léo
Published: September 2023

When listening to speech sounds, listeners are able to exploit acoustic features that mark the boundaries between successive words, the so-called segmentation cues. These cues are typically investigated by directly manipulating features that are hypothetically related to segmentation. The current study uses a different approach based on reverse correlation, where the stimulus manipulations are based on minimal assumptions. The method was evaluated using pairs of phonemically identical sentences in French, whose prosody was changed by introducing random f0 trajectories and segment durations. Our results support a prominent perceptual role of the f0 rise and vowel duration at the beginning of content words.