bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of serum cytokines and chemokines levels and clinical significance in patients with pemphigus vulgaris—A retrospective study
Authors: You Shuqiong , Ouyang Jianting , Wu Qian , Zhang Yaozhong , Gao Jian , Luo Xiaojia , Wang Yuan , Wu Yongzhuo , Jiang Fuqiong
Published: September 2024

In this study, we aimed to examine the relationship between the serum cytokine levels of patients with pemphigus vulgaris (PV) and the Pemphigus Disease Area Index (PDAI), along with the presence of anti‐desmoglein (Dsg) 1 antibody, anti‐Dsg3 antibody and co‐infection among patients with pemphigus vulgaris. This retrospective study included 62 PV patients and 59 healthy individuals who attended the Second Affiliated Hospital of Kunming Medical University from November 2014 to November 2022. The serum concentrations of cytokines and chemokines were assessed using the Luminex 200 System (a high‐throughput cytokine detection method). Additionally, anti‐Dsg1 and anti‐Dsg3 antibodies were determined through enzyme‐linked immunosorbent assay, while disease severity was evaluated using the PDAI scoring system. The PV group exhibited elevated levels of Th1 cytokines (such as interleukin (IL)‐1RA, IL‐1β, IL‐2, IL‐12p70, GM‐CSF, TNF‐α, IL‐18, IFN‐γ), Th2 cytokines (IL‐5, IL‐10, IL‐13) and Th17/Th22‐related cytokines (IL‐17A, IL‐22) compared to the healthy control group (p < 0.05). Conversely, the levels of chemokines (macrophage inflammatory protein‐1 alpha (MIP‐1α), stromal cell‐derived factor‐1 alpha (SDF‐1α), interferon‐inducible protein‐10 (IP‐10), Regulated on Activation in Normal T‐Cell Expressed And Secreted (RANTES), growth‐regulated on‐gene‐alpha (GRO‐α), MIP‐1β) and Th2 (IL‐31) were lower in the PV group compared to the healthy control group (p < 0.05). No significant differences were observed in other cytokines and chemokines (p > 0.05). Additionally, IL‐7, IFN‐γ, IL‐18 and GRO‐α showed positive correlations with PDAI, IL‐6 correlated positively with anti‐Dsg3 antibody levels, and IL‐12p70, IL‐18, and IFN‐γ correlated positively with anti‐Dsg1 antibody levels. Furthermore, IL‐15 exhibited a positive association with skin infections. PV patients have elevated levels of various cytokines and chemokines, and there are different degrees of elevation in cytokines and chemokines associated with the activation of various T cell subsets. PDAI and the Dsg1 antibody levels are mainly related to the Th1‐related cytokines.
A review of artificial sebum formulations, their compositions, uses and physicochemical characteristics
Authors: Rosik Nicole , Preece Jon A. , Fryer Peter J. , McRobbie Ian , Zhang Zhenyu J.
Published: September 2024

Sebum is a complex mixture of skin lipids responsible for lubrication, moisture retention and skin protection from external factors such as bacteria and fungi. The physicochemical properties of natural sebum are not well understood and are not easily accessible. Artificial sebum is widely used for sebum‐related research such as dermal bioaccessibility, fingerprint production, dermatology, removal and sebum studies. It was found that the composition of artificial sebum affects the bioaccessibility of metals and drugs as well as the growth of some strains of bacteria. Squalene present in sebum was also found to be responsible for creating yellow stains on fabrics, whereas an increased concentration of fatty acids and triglycerides can lead to higher malodour of fabrics. Moreover, sebum and artificial sebum are poorly characterized with only 20 of 81 formulations characterized by certain techniques such as differential scanning calorimetry, nuclear magnetic resonance and thin‐layer chromatography. This article reviews the artificial sebum formulations reported in the open literature between 1965 and 2023. We have discussed the compositions, uses and characterization techniques of artificial sebum used in the previous work and compared their properties to those of human sebum. A total of 81 artificial sebum formulations were found across the literature with 17 new formulations identified. The artificial sebum composition varies greatly between publications and there is no consistent formulation. There is a wide range of chemicals that are used as the main components of artificial sebum. We have highlighted the effect of chemical composition and individual compounds on the overall properties of the artificial sebum reported, and recommend that there is a great potential for creating personalized cosmetics and home care products once the characteristics of sebum are better understood.
Effect of ultrasound pretreatment combined with different drying methods on the quality and bioactive compounds of broccoli stems
Authors: You Wanli , Chen Si , Zhang Jinglin , Ru Xueyin , Xu Feng , Wu Zhengguo , Jin Peng , Zheng Yonghua , Cao Shifeng
Published: September 2024

The effects of ultrasound (US) pretreatment combined with drying process on storage quality maintenance and bioactive compound accumulation of broccoli stems were investigated. Results indicated that US pretreatment (λ = 8.5 mm) delayed the decline of L* value and ascorbic acid content but inhibited the increase of a* and b* values, browning index, and microbial counts of fresh‐cut broccoli stems. Furthermore, the US application enhanced total phenolics content by activating phenylalanine ammonia‐lyase, cinnamate‐4‐hydroxylase, and 4‐coumarate‐CoA ligase in phenylpropane metabolism. Meanwhile, it also promoted γ‐aminobutyric acid (GABA) accumulation by upregulating activities of diamine oxidase, polyamine oxidase, and aminoaldehyde dehydrogenase in GABA shunt and polyamine degradation pathway, respectively, which in turn, accelerated the biosynthesis of GABA from polyamines and glutamate. In addition, compared with other three drying methods, the combined vacuum freeze drying (VFD) could further retain the sensory attributes and bioactive compounds to a maximum extent in dehydrated broccoli stems. Hence, current findings illustrated that US pretreatment combined with VFD process is beneficial for commercial quality maintenance and nutritional value enhancement, thus providing new perspectives on the comprehensive utilisation of broccoli stems.
Avocado oil used to modify rice starch and prepare gluten‐free cakes: physical–chemical, microbiological, sensory, and nutritional evaluations
Authors: Nunes Gabrielle Tomaz , Frasson Sabrina Feksa , Zimmer Tailise Beatriz Roll , da Costa Diego Araujo , Colussi Rosana , Borges Caroline Dellinghausen , Gandra Eliezer Avila , Mendonça Carla Rosane Barboza
Published: September 2024

This study aimed to use modified rice starch by heat‐moisture treatment with avocado oil (AO) in gluten‐free cakes. Four cake formulations were prepared with native or modified rice starch with AO or soybean oil (control). The cake's sensory, microbiological, technological, nutritional, and bioactive compound characteristics were analysed. All formulations were sensorily acceptable (acceptance index: 72.44% to 79.44%) and microbiologically safe. The cake formulated with modified starch and AO exhibited the best textural properties, softness, and colour, and demonstrated the lowest in vitro digestibility (81.52 ± 2.75%) and glycaemic index (88.04 ± 3.83). AO resulted in higher levels of phenolic compounds in the cake (112.91 ± 1.8 to 237.38 ± 4.1 mg EAG.100 g−1). The use of modified rice starch and AO showed greater potential in the application of gluten‐free cake than those with native starch, resulting in improved product characteristics and good technological and sensory properties. It has also become a promising alternative in gluten‐free food products.
Plasma renin activity as a marker for predicting the antihypertensive effect of switching to sacubitril/valsartan in treated hypertensive patients: Usefulness in daily clinical practice
Authors: Horio Takeshi , Iwashima Yoshio , Yoshiyama Minoru , Fukuda Daiju , Rai Tatemitsu , Fujimoto Kohei
Published: September 2024

The authors investigated the antihypertensive effect of sacubitril/valsartan (Sac/Val) when switching from other drugs and assessed whether brain natriuretic peptide (BNP) or plasma renin activity (PRA) before drug switching was a predictor of blood pressure lowering after switching to Sac/Val. In 92 patients with treated hypertension, clinic blood pressure, plasma BNP, and PRA were examined before and after switching to Sac/Val. Clinic systolic and diastolic blood pressures significantly decreased after drug switching to Sac/Val (p < .0001, respectively). The level before drug switching of BNP had no correlation with the change in systolic blood pressure (Δ‐SBP) before and after switching to Sac/Val, but that of PRA was significantly correlated with Δ‐SBP (r = .3807, p = .0002). A multiple regression analysis revealed that PRA before drug switching was an independent determinant of Δ‐SBP. Our findings suggest that low PRA may become a useful marker to predict the antihypertensive effect of switching to Sac/Val in treated hypertensive patients.
Color Comparison Between Intraoral Scanner and Spectrophotometer Shade Matching: A Systematic Review and Meta‐Analysis
Authors: Vitai Viktória , Németh Anna , Teutsch Brigitta , Kelemen Kata , Fazekas Alíz , Hegyi Péter , Németh Orsolya , Kerémi Beáta , Borbély Judit
Published: September 2024

Objective

This systematic review and meta‐analysis compared the accuracy of intraoral scanners and spectrophotometers in determining tooth shade.

Materials and Methods

An electronic search of five databases (PubMed, Scopus, Embase, Web of Science, CENTRAL) was conducted on October 19, 2023. A total of 163 studies were identified from the databases, of which 23 articles were eligible for inclusion. In vivo and in vitro quasi‐experimental studies were included. After data extraction, a quantitative analysis was performed to determine the accuracy of the intraoral scanner in subgroups using four outcomes: trueness and precision with different measurement locations. A random‐effects model was used to pool effect sizes. The pooled proportion with a 95% confidence interval (CI) was used for the effect size measure.

Results

Eleven articles were included in the meta‐analysis. Trueness with the intraoral scanner was between 0.28 (CI: 0.09–0.60) and 0.38 (CI: 0.24–0.53). Repeatability was between 0.81 (CI: 0.64–0.91) and 0.85 (CI: 0.74–0.92). Trueness showed low, and precision had moderate certainty of evidence.

Conclusion

The trueness of shade matching with intraoral scanners is low compared to spectrophotometers, although the precision is considered high and is similar to spectrophotometers.

Clinical Significance

Shade determination with intraoral scanners is not recommended.
Successful Treatment of Cryptococcus gattii in an Immunocompetent Adult Rhesus Macaque (Macaca mulatta)
Authors: Taylor Joshua M. , Cullin Cassandra O. , Haertel Andrew J. , Lewis Anne D. , Renner Lauren
Published: September 2024

An adult female rhesus macaque presented during routine annual physical examination for evaluation of a 2.5‐cm diameter superficial ulcerated dermal lesion that was subsequently diagnosed as a systemic fungal infection caused by Cryptococcus gattii. Cryptococcus gattii is one of several basidiomycetic yeasts responsible for pulmonary, neurologic, and disseminated infections in humans and animals. This report describes the diagnosis, management, and clinical resolution of a C. gattii infection in an immunocompetent 5‐year‐old female rhesus macaque.
“It does change the narrative for health and social care” views of clinical and homeless service staff about the use of intellectual disability screening tools within homeless support pathways in the north of England
Authors: Metcalfe Dale , McKenzie Karen , Murray George , Shirley Alex
Published: September 2024

Homelessness is a worldwide health inequality. People with intellectual disability represent a relatively high proportion of homeless people, and for many their intellectual disability is not recognised. The study intended to obtain stakeholder views about how intellectual disability screening can be integrated into the support pathway for people who are homeless. A qualitative approach was taken using Thematic Analysis. Nine staff, who work with homeless people or are involved in the intellectual disability assessment pathway, were interviewed. Analysis produced three themes, each containing two subthemes. ‘Current routes to support’ investigates experiences of the existing pathway; ‘Labels’, explores views about making intellectual disability visible; ‘Creating a pathway,’ outlines ideas about developing and implementing a screening pathway between services. The results help inform how current practices of identifying people with intellectual disability might be improved and the role of screening in this. These results, when combined with other research around screening tools, provide insight into how intellectual disability screening can be integrated within services.
Dietary patterns and periodontitis: A systematic review
Authors: Shi Xinyi , Zhu Peijun , Du Mi , Deng Ke , Li Ping , Sáenz‐Ravello Gustavo , Xu Shulan , Li An
Published: September 2024

The systematic review aimed to investigate the associations between index‐based dietary patterns and the risk and severity of periodontitis. Four public databases were searched for relevant published articles. Two independent researchers conducted the study selection, quality assessment, and data extraction. Methodological quality of the selected studies was evaluated using Joanna Briggs Institute Checklists. The review was registered with PROSPERO (CRD42023395049). Twenty‐five studies were eligible for this review, including 23 cross‐sectional studies and two prospective cohort studies. The most utilized dietary indices were the Healthy Eating Index (HEI), the Mediterranean Diet Score (MDS), and the Dietary Inflammatory Index (DII). The results indicated a positive association between higher diet quality (i.e., higher HEI and MDSs and lower DII scores) and healthier periodontal status. Subgroup meta‐analysis for four studies utilizing HEI and CDC/AAP case definition indicates the protective effect of higher HEI scores on the risk of periodontitis (OR [95% CI] = 0.77[0.68, 0.88]) with statistical significance (Z = 3.91 [p < 0.0001]). Dietary assessment was conducted by validated food frequency questionnaires (FFQ) in 52% of the studies and 24‐h dietary recalls in 36% of the studies. One study utilized a validated 15‐item questionnaire to measure patients' adherence to the Mediterranean Diet (QueMD). The quality assessment showed that all studies were of high quality. High HEI and MDSs and low DII scores were associated with a low risk of periodontitis and better periodontal conditions. The standardized and repeatable diet guidelines might be provided for preventing periodontitis. Future prospective studies and clinical trials are needed to confirm this causal association.
Forecasting the yield curve: the role of additional and time‐varying decay parameters, conditional heteroscedasticity, and macro‐economic factors
Authors: Caldeira João F. , Cordeiro Werley C. , Ruiz Esther , Santos André A.P.
Published: September 2024

In this article, we analyse the forecasting performance of several parametric extensions of the popular Dynamic Nelson–Siegel (DNS) model for the yield curve. Our focus is on the role of additional and time‐varying decay parameters, conditional heteroscedasticity, and macroeconomic variables. We also consider the role of several popular restrictions on the dynamics of the factors. Using a novel dataset of end‐of‐month continuously compounded Treasury yields on US zero‐coupon bonds and frequentist estimation based on the extended Kalman filter, we show that a second decay parameter does not contribute to better forecasts. In concordance with the preferred habitat theory, we also show that the best forecasting model depends on the maturity. For short maturities, the best performance is obtained in a heteroscedastic model with a time‐varying decay parameter. However, for long maturities, neither the time‐varying decay nor the heteroscedasticity plays any role, and the best forecasts are obtained in the basic DNS model with the shape of the yield curve depending on macroeconomic activity. Finally, we find that assuming non‐stationary factors is helpful in forecasting at long horizons.
Self‐supervised representation learning of metro interior noise based on variational autoencoder and deep embedding clustering
Authors: Wang Yang , Xiao Hong , Zhang Zhihai , Guo Xiaoxuan , Liu Qiang
Published: September 2024

The noise within train is a paradox; while harmful to passenger health, it is useful to operators as it provides insights into the working status of vehicles and tracks. Recently, methods for identifying defects based on interior noise signals are emerging, among which representation learning is the foundation for deep neural network models to understand the key information and structure of the data. To provide foundational data for track fault detection, a representation learning framework for interior noise, named the interior noise representation framework, is introduced. The method includes: (i) using wavelet transform to represent the original noise signal and designing a soft and hard denoising module for dataset denoising; (ii) deep residual convolutional denoising variational autoencoder (VAE) module performs representation learning with a VAE and deep residual convolutional neural networks, enabling richer data augmentation for sparsely labeled samples by manipulating the embedding space; (iii) deep embedding clustering submodule balances the representation of reconstruction and clustering features through the joint optimization of these aspects, categorizing metro noise into three distinct classes and effectively discriminating significantly different features. The experimental results show that, compared to traditional mechanism‐based models for characterizing interior noise, this approach offers a data‐driven general analysis framework, providing a foundational model for downstream tasks.
Jacobi–Fourier phase masks as ophthalmic elements to correct presbyopia
Authors: Salas‐Sanchez Ángel , González‐Amador Enrique , Padilla‐Vivanco Alfonso , Toxqui‐Quitl Carina , Arines Justo , Acosta Eva
Published: September 2024

Purpose

Investigations into the correction of presbyopia have considered lens design, clinical implications and the development of objective metrics such as the visual Strehl ratio. This study investigated the Jacobi–Fourier phase mask as an ophthalmic element in the correction of presbyopia. The goal was to develop a contact or intraocular lens whose performance was largely insensitive to changes in pupil diameter.

Methods

Numerical simulations based on Fourier optics were performed to evaluate three different Jacobi–Fourier polynomials, with the aim of providing a range of clear vision (1 Dioptre (D)). Performance was evaluated for three pupil sizes (6, 4 and 2 mm), while polychromatic images were simulated using three different wavelengths (656.3, 587.6 and 486.1 nm). The Neural Transfer function was included in the simulation. To validate the method and results, we used the Visual Strehl combined objective metric (VSCombined) currently used in visual optics. This metric gives more weight to the phase transfer function and is more suitable for non‐symmetrical phase functions.

Results

Numerical validation showed the suitability of the Jacobi–Fourier phase masks for extending the range of clear vision of presbyopic eyes, providing a visual acuity of at least 0.10 logMAR (6/7.5 Snellen) at all distances between 1 and 6 m. The results show a range of clear vision of 1D was not affected by changes in pupil size, an increase in retinal image contrast accompanied by image artefact reduction by increasing the radial order of the Jacobi–Fourier phase mask and a reduction of wavelength dependence of the retinal images. These results are supported by simulated images and the objective criterion VSCombined.

Conclusions

The use of Jacobi–Fourier phase masks as ophthalmic elements for presbyopic correction show promising results, with a good range of clear vision and reduced dependence on pupil size and chromatic aberration.
Accountability as a function of power relationships in public governance networks
Authors: Eckersley Peter , Lakoma Katarzyna , Murphy Pete , Caygill Tom , Pell Charlotte
Published: September 2024

In public governance, power and accountability are inextricably linked. However, although an integrated exploration of these concepts could enhance our understanding of how governance operates, few studies have examined them together. Drawing on resource dependency theory, we suggest that power relationships within networks shape accountability and have a concomitant impact on the prevailing governance paradigm. Specifically, where principals possess important resources that enable them to exercise power over agents and hold them to account through hierarchical mechanisms, Traditional Public Administration approaches predominate. Where resources are diffused within elite networks in New Public Management contexts, individual actors can exercise greater power to achieve their objectives, and accountability arrangements become increasingly multidirectional and complex. Finally, if resources are shared across society as in the New Public Governance paradigm, actors generate power with each other to achieve shared goals, and accountability relationships are more horizontal with a focus on learning.
Relationship of sustainable development goals, holistic nursing competence, and social justice advocacy role in public health nurses
Authors: Karatana Özlem , Karaman Mesut
Published: September 2024

Objective

This study was conducted to examine the relationship between public health nurses' holistic nursing and social justice advocacy competencies in terms of their attitudes toward sustainable development goals.

Design

Cross‐sectional survey.

Sample

The study sample consisted of 384 public health nurses.

Measurements

Data were collected with the personal information form, the Attitudes toward Sustainable Development Scale, the Holistic Nursing Competence Scale, and the Social Justice Advocacy Scale.

Results

The sub‐dimensions of environment, public, education, and economy were found to significantly affect social justice advocacy, and the indirect effects of 0.191, 0.222, 0.205, and 0.201 were found to be statistically significant with the inclusion of holistic nursing competence in the model, respectively. It was found to explain 32%, 30%, 29%, and 22% of the total effect, respectively.

Conclusion

It supports the claim that developing public health nurses' holistic nursing competence and social justice advocacy skills is an important criterion for achieving sustainable development goals.
When fMRI came to Bergen and Norway – as I remember it
Authors: Hugdahl Kenneth
Published: September 2024

In this personal recollection, I review the beginning of functional magnetic resonance imaging (fMRI) research in Norway, i.e., at the University of Bergen and the Haukeland University Hospital in Bergen. Research with fMRI had already started in Bergen in 1993, and the small group of researchers involved were the first to take up this new method for studies of the brain and brain‐behavior relationships. This article is a recollection of the early years of how the field started and developed in Bergen, Norway over the years, including basic as well as clinical research, and how the research also led to successful innovation and commercialization through the establishment of a MedTech company, NordicNeuroLab (NNL), that has delivered products to more than 2,000 university hospitals worldwide.
Control of a Directional Downhole Drilling System Using a State Barrier Avoidance Based Method
Authors: Tian Dongzuo , Song Xingyong
Published: September 2024

Vibrations such as bit-bouncing, stick–slip, and whirl motion can significantly reduce downhole drilling's performance and efficiency. These phenomena are likely to arise once the dynamical states of drilling fall into undesired operating regimes, as verified by both theoretical analyses and experimental studies. To effectively avoid such undesired operating conditions of a downhole drilling process, this paper introduces an advanced nonlinear state-constrained control method to formulate a setpoint tracking problem of high-order directional drilling dynamics under state constraints. These constraints are carefully defined using the field test results, and their shapes are in complex state-space regions, causing additional complexity to the control design. Moreover, unlike vertical drilling, the directional drilling system requires modeling of coupled axial and torsional dynamics with a higher degree-of-freedom (DOF). In this study, the proposed method will tackle these challenges by converting the original high-order constrained control problem into a standard nonlinear control problem. Leveraging on the linear parameter varying (LPV) method that is applied to the converted system, we can actively prevent drilling from falling into the undesired regimes, to achieve the constrained control objective.
Coupled Flow and Thermal Radiation Simulation for Molten Salt Flow in Random Pebble Bed
Authors: Yuan Haomin , Dai Dezhi , Lan Yu-Hsiang
Published: September 2024

The design of a pebble bed core cooled by molten salt represents one of the Gen IV nuclear reactor concepts. This design lays the foundation for the Fluoride High-temperature Reactor (FHR), which harnesses the advantages of both pebble bed and molten salt cooling systems. While thermal radiation plays a negligible role in heat transfer under forced convection, it becomes a significant factor under mixed convection and natural convection conditions, profoundly altering the temperature profile.

In our earlier investigation of pebble bed behavior, the influence of thermal radiation was not considered. To address this, the P1 model was incorporated into the Spectral Element Code Nek5000/NekRS. The P1 model necessitates an optical length greater than 3, a condition consistent with the characteristics of molten salt within the pebble bed.

The initial step involved verifying and validating the P1 model by comparing it to exact solutions and using OpenFOAM for benchmark cases. Subsequently, the P1 model was applied to simulate heat transfer within a random pebble bed containing 1568 pebbles, operating at an exceptionally low Reynolds number to avoid turbulence. To ensure the accuracy, a parallel simulation was conducted of the same scenario using OpenFOAM as a reference.
3D Printed Capillary-Driven Cold Plate for Hybrid Two-Phase Cooling System
Authors: Shaeri Mohammad Reza , Demydovych Maksym
Published: September 2024

In this study, a hybrid two-phase cooling system (HTPCS) was developed for thermal management of high-heat-flux electronics. The HTPCS integrates capillary-driven evaporation from wicks with mechanically pumped two-phase cooling. The capillary-driven evaporation takes place within a compact cold plate housing eight heaters situated on both sides of the cold plate, each heater dedicated to an individual evaporator wick. The significance of this study lies in fabricating the entire cold plate through one single 3D printing process. Constructed from AlSi10Mg using a Direct Metal Laser Sintering process, the cold plate operated with the refrigerant R245fa across a broad range of heat fluxes. Comparative analysis was performed with a 3D printed plain cold plate (i.e., without evaporator wicks). The HTPCS demonstrated stable operation at heat fluxes exceeding 305 W/cm2, marking a more than 103% improvement in the upper limit operation compared to the plain cold plate. Within this heat flux range, the measured thermal resistances achieved by the HTPCS were ∼ 0.17 to 0.24 K-cm2/W. The developed HTPCS emerges as a promising solution for thermal management in high-heat-flux applications. Furthermore, the fact that the fabrication process for the cold plate involves only one 3D printing step significantly streamlines the commercialization of the HTPCS developed in this study.
Measurements of Heat Transfer in Flowing Granular Media
Authors: Alsharif Mohamed
Published: September 2024

In recent years, there has been an increased interest in the thermal behavior of granular solids because of many relatively new industrial applications. Process industries involving particulate solids being immersed or carried in a “continuous” fluid phase include chemical, petroleum, metallurgical, food, and pharmaceuticals, as well as many fluidized bed operations. An investigation was conducted of the heat transfer characteristics of a variety of flowing particulate solid media. Five different granular materials were studied in a vertical gravity-driven flow through an electrically-heated circular stainless steel tube test section. From measurements of wall temperature distribution, particle bulk inlet temperature, radial temperature distribution of the particle flow at the test section exit, and mass flow rate determination of local and average heat transfer coefficients along the test section were made. The key to this proposed approach lies in the use of proper equations to evaluate the thermophysical properties of the medium in the critical region adjacent to the heat transfer surface, i.e., voidage, density, thermal conductivity, thermal diffusivity, and specific heat. The design and construction of the thermal loop test facility used in this study is described in this paper. Comparison of the experimental results with available experimental data and predictions of various models appearing in the literature were made. Agreement existed with the modified versions of the packet model. However, for correlations based upon and compared with only limited data, agreement was not satisfactory.
Thermal Transport Mechanisms in Lunar Regolith at Low and High Temperatures
Authors: Cao Jiahui , Lee Jaeho
Published: September 2024

Many planetary bodies, such as the Moon, comet, asteroids, and meteoroids, are covered by regolith and exhibit a wide range of temperature variations from daytime to nighttime and across different altitudes. The thermal conductivity of regolith is a critical parameter in determining surface heat flow and temperature variation. In this study, we develop a comprehensive model, combining a semi-empirical approach based on Watson’s equation and an effective medium theory approach based on morphology and mineral composition, to predict the temperature-dependent thermal conductivity of lunar regolith. We study the solid thermal conductivity (ks) induced by the conductive interactions among solid particles and the radiative thermal conductivity (kr) caused by radiative heat transfer through the void spaces in porous media. We find the conductive contribution to be a complex function of morphology, particle size, packing, and the efficiency of contacts between adjacent particles, whereas the radiative contribution strongly depends on the emissivity, particle size, and porosity. More specifically, we estimate the elastic-wave-driven crystalline thermal conductivity (kcr) and the random-walk-driven amorphous thermal conductivity (kam) and evaluate the impact of crystallinity on ks. We further consider the electron contribution to kcr and the radiative influence on kr when metal-rich meteorites are present in the regolith. Considering all the relative contributions to the effective thermal conductivity (keff), we find that keff at low temperatures is dominated by the solid contribution (i.e., ks ∝ [(1 – y)kcr,p + y · kcr,e] + (1 – x)kam) and exhibits substantial variations depending on the degree of crystallinity (x) and metallic composition (y). We observe three distinct thermal transport behaviors for the corresponding solids: (1) kcr,p first increases rapidly to a peak at around 10 K and then decreases monotonically with increasing temperature due to substantial phonon-phonon scattering; (2) kcr,e increases linearly with temperature and reaches a plateau for T > 100 K due to the increase of electronphonon scattering; (3) kam exhibits a unique temperature dependence due to its random walk nature. Furthermore, we find that keff at high temperatures is dominated by the radiative contribution, where kr ∝ T3. This work identifies various thermal transport mechanisms in lunar regolith with respect to microstructures, morphology, composition, and temperature. It provides valuable insights into the fundamental thermophysical properties of regolith concerning future planetary exploration.
Carbon Emission Model of Power Industry Based on Life Cycle Perspective in China
Authors: Zhao Yurong , Dong Yahong , Cheng Hong , Amin Khan Tarip , Li Wei , Mehmood Jasim
Published: September 2024

China is currently the largest carbon emission country in the world. In China, the power industry’s carbon emissions accounted for more than 40% of the total. Moreover, annual electricity consumption is still rising, increasing by 6% to 9.15 trillion kWh in 2023. Therefore, the carbon emission reduction of the power industry is particularly important for achieving the goals of carbon neutrality and carbon peaking in China. From the perspective of the life cycle, the power industry can be divided into three major phases: the generation side, the transmission side, and the consumption side. Starting from these three phases, this paper constructs a life cycle carbon emission model of power systems, incorporating digital monitoring technology to realize the real-time monitoring and management of carbon emissions from power systems in China. On the consumption side, this paper selects the liquor industry in Guizhou as a typical case. It calculates the carbon emissions of some units with a capacity of 6000 kW and above in Guizhou in a month by constructing a carbon emission model. The realization of real-time carbon emission monitoring of the power grid will help the power industry achieve the goal of “dual carbon” at an early date.
Temperature Field Reconstruction of Surfaces Heated Through Radiative Heat Transfer Using Convolutional Neural Networks
Authors: Aldeia Machado Luiz C. , Coppo Leite Victor , Merzari Elia , Wright Lesley , Ibarra Lander , Ponciroli Roberto , Bhat Pramatha , Hassan Yassin
Published: September 2024

Diverse applications require us to know the value of a given physical quantity in real time. For many applications, we can rely on probes to fulfill this task. However, this approach can be challenging when we need to know these quantities in many locations over a given domain due to the spatial limitation involved. In this context, using Convolutional Neural Networks (CNN) can offer a good option to deal with such a problem. A well-trained physics-informed CNN can reconstruct the distribution of a given physical quantity over a domain using only a few sensors, allowing us to reconstruct the desired field distribution even in a limited space or complex geometries where a large array of sensors remains impractical.

In this work, we will present the initial approach to developing a real-time tool for monitoring the thermal behavior of nuclear reactor pressure vessels. Based on an experimental setup, the team developed a computational model using the Multiphysics Object-Oriented Simulation Environment (MOOSE) framework, where the Ray Tracing and Heat conduction modules were used to evaluate the temperature distribution over a convex metal surface heated through radiative heat transfer. This metal surface represents a section of a heated nuclear reactor vessel wall. The team verified our computational model against the available experimental data. Part of the data generated by the MOOSE model was used to train the Convolutional Neural Network to reconstruct the vessel wall’s outer surface temperature. The CNN generalization was then verified against the experimental and computational data. The predicted temperature distribution over the vessel’s outer wall presented an R-square metric of 0.9991 when compared against the MOOSE model.
Heat Transfer Coefficients and Film Cooling Effectiveness on the Endwall of a Transonic Turbine Vane Measured With Binary Pressure Sensitive Paint
Authors: Burdett Timothy A. , Wright Lesley M.
Published: September 2024

Film cooling is a key technique used to reduce heat transfer from hot combustion gases to stationary and rotating components in a gas turbine engine. In high-performance engines, the endwall experiences high heat gains due to flattened mainstream temperature profiles and low solidity ratio airfoils. In this study, the thermal performance of upstream film cooling holes on the endwall of a transonic, five-vane, annular sector cascade was characterized. Transonic measurements of the adiabatic film cooling effectiveness are typically performed with binary pressure sensitive paint (BPSP), which has a reference sensor to allow compensation for temperature variation. A novel experimental technique has been demonstrated that extends the measurement capability of binary pressure-sensitive paint by using the reference sensor to measure the temperature and heat transfer coefficient. These measurements were performed in a transient heat transfer experiment assuming 1D conduction through a semi-infinite solid exposed to a convection boundary. The mainstream exit Mach number was 0.9, and the coolant-to-mainstream density ratio was 1. The coolant-to-mainstream mass flow ratio was varied from 0.75% to 1.25%. An optimum mass flow ratio of 0.75% was identified as it provided the lowest area-averaged heat transfer coefficient while increasing it had little impact on the film cooling effectiveness.
Advancements in Ni-P Plating Surfaces for Mitigating Crystallization Fouling in Microchannel Heat Exchangers
Authors: Sun Jia , Li Wei , Cao Biqi , Zhou Jianxin , Wu Zan
Published: September 2024

In pursuit of sustainable energy solutions and to combat the environmental challenges posed by fouling in thermal devices, this study developed Ni-P-TiO2 and Ni-P-Polytetrafluoroethylene (Ni-P-PTFE) surfaces and explored the effectiveness of coatings in minimizing fouling on heat exchange surfaces. We conducted heat exchange experiments to compare the both coating surfaces with copper surface under identical clean conditions in microchannels. Further analyses explored fouling resistance across surfaces at various flow rates and solution hardness, complemented by Scanning Electron Microscope (SEM) images of fouling morphology. The findings revealed that decreasing surface energy and enhancing hydrophobic properties can reduce crystal fouling. Notably, both Ni-P-TiO2 and Ni-P-PTFE surfaces demonstrated superior performance, showing significantly lower thermal resistance compared to copper surface. Despite the increase in thermal resistance with solution concentration, the growth rate of fouling resistance declined gradually. The Ni-P-PTFE coating, benefiting from its lower surface energy and greater hydrophobicity, showed superior looseness and porosity. This study demonstrates the effectiveness of Ni-P-TiO2 and Ni-P-PTFE coatings in reducing fouling thermal resistance, offering a promising approach for improving microchannel device performance.
Thermal Conductivity of Advanced 3D Printed Polymers
Authors: Jacques Cory , Letcher Todd , Michna Gregory J.
Published: September 2024

Additive manufacturing is increasingly being employed in the production of parts for end-use applications. Fused deposition modeling (FDM) is a type of 3d printing in which a molten thermoplastic is extruded to create the desired geometry. FDM has not been significantly used in heat transfer applications, but if parts with somewhat higher thermal conductivity than is currently obtainable with commonly used FDM polymers (ABS and PLA) can be produced, many potential heat transfer applications could be studied for potential use in real-world applications such as heat exchangers or heatsinks. We have previously presented our work in developing an apparatus for measuring the thermal conductivity of 3d printed materials. In the experimental study presented here, the effective thermal conductivity of many advanced FDM materials is measured using that purpose-built apparatus. The performance of the test apparatus was first validated using a sample of acrylic, a low-conductivity material in which the conductivity is well understood. Next, the thermal conductivities of parts printed from several advanced 3d printing polymer filaments were measured. The filaments tested included natural PLA, as well as composite filaments of aluminum and copper with PLA. The parts produced from composite filaments show a significantly higher thermal conductivity than those using the pure polymer material.
Distributed Single-Mode Optical Fiber High Temperatures Measurements
Authors: Hlifka Brian M. , Kinzel Edward C.
Published: September 2024

This paper investigates the application of single-mode silica optical fibers for capturing distributed high temperatures up to 1100°C. The optical fibers were interrogated with Luna Innovation’s optical backscattering reflectometer (OBR). The Rayleigh backscattering from the inherent inhomogeneities in the core (9 μm) was monitored to characterize the constraints of integrated SM-fiber in high-temperature environments. A relationship between time, temperature, and stress directly impacts a quality factor metric. This metric measurement is based on the degree of autocorrelation between the measured and reference Rayleigh backscattering spectra along its distributed length. Gradual creep of the natural defects in the microstructure occurs at temperatures around 750°C, and the rate of these shifts intensifies with increasing temperature, time, and stress. A continuous high-temperature measurement can be done by defining a new reference, but there is a limited time before introducing noise. This paper will demonstrate the ability of a single-mode optical fiber to temperatures up to 1100°C by defining a new reference Rayleigh spectrum. Also, the viability of an optical fiber is analyzed based on the quality factor, which provides a correlation between temperature and time.
CFD Modeling of End Effects of Gas Cooler Heat Exchanger for sCO2 Power Blocks
Authors: Duggirala Vyas , Hegde Venkata N. , Reddy Venkateswara , Kumar Pramod , Muley Arun
Published: September 2024

Supercritical Carbon dioxide (sCO2) Brayton cycle power blocks provide unique advantages for power generation through flexible operation and highly compact power plants. Gas cooler heat exchangers for sCO2 power blocks are crucial to help maintain ideal conditions at the compressor inlet to maximize net power output and cycle efficiencies. Design, modeling and optimization of these heat exchangers is a challenging task given the proximity of operating conditions to the critical point. Microchannel heat exchanger configurations with repeating unit cell architecture are preferred to attain compact form factors while maximizing the heat transfer rates at reasonably low-pressure drop penalties. The current work investigates the end effects of surface heat loss and bounding walls of heat exchanger stack on thermo-hydraulic performance. A hybrid approach of unit cell CFD modeling coupled with a Thermal Resistance Network (TRN) for estimating complete stack performance is presented under end effects. A compensation strategy to mitigate the variations in pinch temperature is studied under different stack configurations. The findings from the current work indicate that the presence of end effects manifests as variations of channel pinch temperatures leading to flow maldistribution across the heat exchanger stack.
Investigation of Liquid Cooling for Lithium-Based Batteries in Phase Change Materials Using Metal Foams: a Numerical Approach
Authors: Arumugam Aanandsundar , Buonomo Bernardo , Manca Oronzio
Published: September 2024

This study addresses the critical issues of thermal management in electric vehicles focusing on the significant challenges related to the thermal control of rechargeable electric batteries. The optimal temperature maintenance is crucial for sustaining the electric vehicles autonomy by isolating the batteries from external climatic factors and temperature peaks during operation. In this numerical study, a threedimensional cylindrical lithium-polymer based single battery module model is employed. The thermal control process involves the utilization of phase change material (PCM) embedded in metal foam. The battery is further cooled through convective liquid flow facilitated by various tube arrangements. The model is implemented using the finite volume method. Various cases are simulated considering two different PCM’S namely RT25HC and RT 35 embedded with metal foam of two different pore densities of 20 and 40 PPI at three different C-rates of 0.25C, 0.5C and 1C respectively. The study further provides a comprehensive insight into temperature distribution along the surface of the battery during the process of discharge in terms of liquid fraction, maximum surface temperature and the maximum temperature attained by the battery model and the maximum temperature recorded by the PCM materials using the above thermal control arrangement.
Effect of Reactor Configuration on the Performance of a Closed Thermochemical Energy Storage System
Authors: Chate Akshay , Jain Kartik , Dash Susmita , Dutta Pradip
Published: September 2024

Thermochemical energy storage systems (TESS) offer higher volumetric energy density compared to sensible and latent heat storage systems. TESS utilizes endothermic dissociation reaction for thermal energy storage (charging process), and the stored thermal energy is subsequently retrieved by performing a reversible exothermic reaction (discharging process). The reactor of the TESS forms a critical system component as endothermic-exothermic reactions take place in it. The present study focuses on the effect of various reactor configurations on the performance of a potassium carbonate salt hydrate based closed TESS, with the help of numerical studies. The cylindrical and flat type of reactor configurations are commonly used for a closed TESS. The cylindrical reactor configuration offers volumetric compactness but poses challenges such as limited water vapor flow area for penetration into the salt hydrate domain. It is observed that the provision of annular passage for water vapor flow and U-tubes for heat transfer fluid (HTF) flow significantly improve the performance of a cylindrical reactor during the discharging process. Around 69 % of the reactant is consumed by the end of 60 minutes of discharging process with the provision of annular passage for water vapor flow, as opposed to only about 10 % conversion without the provision of the annular passage. On the other hand, a flat reactor configuration provides a larger area for water vapor flow but with higher reactor volume requirement. To reduce the volume requirement, a reactor configuration with multiple stacks of smaller flat reactors is recommended. The addition of metallic fins to the flat reactor results in noticeable improvement. During the discharging process of a flat reactor without fins, complete conversion is achieved in 44 minutes. Whereas in flat reactor with HTF tubes through the salt hydrate domain, complete conversion during the discharging process is achieved within 26 minutes, which is 41 % reduction in the completion time.