The 2023 MDPI Annual Report has
been released!
 
19 pages, 4092 KiB  
Article
Ash Properties and Environmental Impact of Coal and Its Blend with Patent Fuel for Climate Sustainability
by Marija Trkmić, Lidija Ćurković, Danijela Ašperger, Magdalena Ujević Bošnjak, Ivana Vinković Vrček and Sanja Matečić Mušanić
Sustainability 2024, 16(11), 4413; https://doi.org/10.3390/su16114413 (registering DOI) - 23 May 2024
Abstract
Fossil fuels are still widely used today, and exploring more sustainable ways of using coal is crucial. One promising approach is to develop a patented fuel with reduced harmful gas emissions during combustion. This study aims to investigate the properties of the ash [...] Read more.
Fossil fuels are still widely used today, and exploring more sustainable ways of using coal is crucial. One promising approach is to develop a patented fuel with reduced harmful gas emissions during combustion. This study aims to investigate the properties of the ash produced by burning steam coal mixed with various ratios of patent fuel. The combustion process was carried out using a standard solid fuel boiler with a power output of 70 kW. The ash samples were analyzed using various analytical methods, and ash leaching tests were conducted. The study found that adding patent fuel to coal affects combustion and ash composition. Determining the thermal stability of ash samples showed that adding patent fuel to coal results in decomposition starting earlier and in stronger combustion. The ash produced by patent fuel–coal mixtures contains lower concentrations of Ba, Cr, Ga, Li, Mn, V, and Zn than pure coal combustion. Leaching tests showed that coal ash leachates had higher concentrations of environmental pollutants, such as As, Cd, Co, Mn, Mo, Sb, and U, than patent fuel leachates. Adding patent fuel to coal affects combustion, ash properties, emissions, and disposal. Understanding these implications can help to develop sustainable coal usage and reduce environmental impact. Full article
(This article belongs to the Special Issue High-Value and Resource-Based Utilization of Coal-Based Solid Waste)
Show Figures

Figure 1

14 pages, 1793 KiB  
Article
Production of Seedlings of Corymbia citriodora Inoculated with Endophytic Bacteria
by Augusto Matias de Oliveira, Caique Menezes de Abreu, Paulo Henrique Grazziotti, Gabriel Faria Parreiras de Andrade, Jaqueline Vieira Gomes, Natanielly Rodrigues Avelino, June Faria Scherrer Menezes, Gabriela Madureira Barroso, José Barbosa dos Santos and Márcia Regina da Costa
Forests 2024, 15(6), 905; https://doi.org/10.3390/f15060905 (registering DOI) - 23 May 2024
Abstract
This study aimed to evaluate the effect of inoculants of endophytic bacteria producing indoleacetic acid (IAA) on the physiological quality of seeds and the production of seedlings of Corymbia citriodora (Hook.) KD Hill & LAS Johnson. In the physiological quality test of the [...] Read more.
This study aimed to evaluate the effect of inoculants of endophytic bacteria producing indoleacetic acid (IAA) on the physiological quality of seeds and the production of seedlings of Corymbia citriodora (Hook.) KD Hill & LAS Johnson. In the physiological quality test of the seeds, the treatments used were individual inoculation with Priestia megaterium, Exiguobacterium sibiricum, Pantoea vagans strain 45URP4-1, and Bacillus sp.; joint effect of the four strains (mix); inoculation only with the carrier (cassava starch and activated charcoal); carrier with 1.0 μg mL−1 of IAA; and non-inoculated control without IAA and without a carrier. In the production of seedlings in a greenhouse, the treatments were the same, except for the mix, which was replaced by P. vagans strain 7URP1-6 (Pvs7), as inoculation with the mix increased the number of abnormal seedlings. In the physiological quality test of seeds, seeds inoculated with the bacteria individually did not have the physiological quality impaired and the carrier created a microenvironment around the seeds, benefiting germination percentage, germination speed index, average germination time, and average germination speed. In the greenhouse, seedlings inoculated with Pvs7, P. megaterium and E. sibiricum were taller, with a larger stem diameter and dry mass of shoot, roots, and total. Seeds inoculated with E. sibiricum had higher averages for height, chlorophyll b content, and shoot and total dry mass, as well as a greater ability to colonize the rhizosphere and roots of C. citriodora, resulting in the production of higher-quality seedlings. Inoculation of seeds of C. citriodora with endophytic bacteria proved to be a promising alternative for plant development. Full article
(This article belongs to the Special Issue Forest Plant, Soil, Microorganisms and Their Interactions)
Show Figures

Figure 1

20 pages, 3313 KiB  
Review
The Role of the Immune System in Pathobiology and Therapy of Myocarditis: A Review
by Cristina Vicenzetto, Andrea Silvio Giordani, Caterina Menghi, Anna Baritussio, Maria Grazia Peloso Cattini, Elena Pontara, Elisa Bison, Stefania Rizzo, Monica De Gaspari, Cristina Basso, Gaetano Thiene, Sabino Iliceto, Renzo Marcolongo and Alida Linda Patrizia Caforio
Biomedicines 2024, 12(6), 1156; https://doi.org/10.3390/biomedicines12061156 (registering DOI) - 23 May 2024
Abstract
The role of the immune system in myocarditis onset and progression involves a range of complex cellular and molecular pathways. Both innate and adaptive immunity contribute to myocarditis pathogenesis, regardless of its infectious or non-infectious nature and across different histological and clinical subtypes. [...] Read more.
The role of the immune system in myocarditis onset and progression involves a range of complex cellular and molecular pathways. Both innate and adaptive immunity contribute to myocarditis pathogenesis, regardless of its infectious or non-infectious nature and across different histological and clinical subtypes. The heterogeneity of myocarditis etiologies and molecular effectors is one of the determinants of its clinical variability, manifesting as a spectrum of disease phenotype and progression. This spectrum ranges from a fulminant presentation with spontaneous recovery to a slowly progressing, refractory heart failure with ventricular dysfunction, to arrhythmic storm and sudden cardiac death. In this review, we first examine the updated definition and classification of myocarditis at clinical, biomolecular and histopathological levels. We then discuss recent insights on the role of specific immune cell populations in myocarditis pathogenesis, with particular emphasis on established or potential therapeutic applications. Besides the well-known immunosuppressive agents, whose efficacy has been already demonstrated in human clinical trials, we discuss the immunomodulatory effects of other drugs commonly used in clinical practice for myocarditis management. The immunological complexity of myocarditis, while presenting a challenge to simplistic understanding, also represents an opportunity for the development of different therapeutic approaches with promising results. Full article
26 pages, 3419 KiB  
Article
Landslide Susceptibility Assessment and Future Prediction with Land Use Change and Urbanization towards Sustainable Development: The Case of the Li River Valley in Yongding, China
by Chi Yang, Jinghan Wang, Shuyi Li, Ruihan Xiong, Xiaobo Li, Lin Gao, Xu Guo, Chuanming Ma, Hanxiang Xiong and Yang Qiu
Sustainability 2024, 16(11), 4416; https://doi.org/10.3390/su16114416 (registering DOI) - 23 May 2024
Abstract
The land use change (LUC) and urbanization caused by human activities have markedly increased the occurrence of landslides, presenting significant challenges in accurately predicting landslide susceptibility despite decades of model advancements. This study, focusing on the Li River Valley (LRV) within the Yongding [...] Read more.
The land use change (LUC) and urbanization caused by human activities have markedly increased the occurrence of landslides, presenting significant challenges in accurately predicting landslide susceptibility despite decades of model advancements. This study, focusing on the Li River Valley (LRV) within the Yongding District, China, employs two common models, namely an analytic hierarchy process–comprehensive index (AHP-CI) model and a logistic regression (LR) model to assess landslide susceptibility (LS). The AHP-CI model is empirically based, with the advantage of being constructible and applicable at various scales without a dataset, though it remains highly subjective. The LR model is a statistical model that requires a training set. The two models represent heuristic and statistical approaches, respectively, to assessing LS. Meanwhile, the basic geological and environmental conditions are considered in the AHP-CI model, while the LR model accounts for the conditions of LUC and urbanization. The results of the multicollinearity diagnostics reflect the rationality of the predisposing factor selection (1.131 < VIF < 4.441). The findings reveal that the AHP-CI model underperforms in LUC and urbanization conditions (AUROC = 0.645, 0.628, and 0.667 for different validation datasets). However, when all the time-varying human activity predisposing factors are considered, the LR model (AUROC = 0.852) performs significantly better under the conditions of solely considering 2010 (AUROC = 0.744) and 2020 (AUROC = 0.810). The CA–Markov model was employed to project the future land use for the short-term (2025), mid-term (2030), and long-term (2040) planning periods. Based on these projections, maps of future LS were created. Importantly, this paper discussed the relationships between landslide management and regional sustainable development under the framework of the UN SDGs, which are relevant to Goal 1, Goal 11, Goal 13, and Goal 15. Finally, this study highlights the importance of integrating strategic land planning, reforestation efforts, and a thorough assessment of human impact predisposing factors with SDG-aligned LS predictions, advocating for a comprehensive, multi-stakeholder strategy to promote sustainable landslide mitigation. Full article
(This article belongs to the Section Hazards and Sustainability)
18 pages, 1369 KiB  
Article
The Influence of Sudden Stratospheric Warming on the Development of Ionospheric Storms: The Alma-Ata Ground-Based Ionosonde Observations
by Galina Gordiyenko, Artur Yakovets, Yuriy Litvinov and Alexey Andreev
Atmosphere 2024, 15(6), 626; https://doi.org/10.3390/atmos15060626 (registering DOI) - 23 May 2024
Abstract
This paper examines the response of the ionosphere to the impact of two moderate geomagnetic storms observed on January 17 and 26–27, 2013, under conditions of strong sudden stratospheric warming. The study uses data from ground-based ionosonde measurements at the Alma-Ata ionospheric station [...] Read more.
This paper examines the response of the ionosphere to the impact of two moderate geomagnetic storms observed on January 17 and 26–27, 2013, under conditions of strong sudden stratospheric warming. The study uses data from ground-based ionosonde measurements at the Alma-Ata ionospheric station (43.25 N, 76.92 E) combined with optical observation data (The Spectral Airglow Temperature Imager (SATI)). Ionosonde data showed that the geomagnetic storms under consideration do not generate ionospheric storms but demonstrate some unusual types of diurnal foF2 variations with large (up to 60%) deviations in foF2 from median values observed during the night/morning periods on 13–15 and 20–23 January, which do not have any relation to solar or geomagnetic activity. Wave-like disturbances in foF2, h’F, and daily averaged foF2 values with a quasi-period of 5–8 days and peak-to-peak amplitude from about 1 MHz to 2 MHz (from 20% to 40%) and ~40 km are observed during the period 9–28 January, after registration of the occurrence of the major SSW event on 6–7 January. The observed variations in the OH emission rate are found to be quite similar to those observed in the ionospheric parameters that assume a community of processes in the stratosphere/mesosphere/ionosphere system. The study shows that the F region of the ionosphere is influenced by processes in the lower ionosphere, in this case by processes associated with sudden stratospheric warming SSW-2013, which led to modification of the structure of the ionosphere and compensation of processes associated with the development of the ionospheric storms. Full article
(This article belongs to the Special Issue Effect of Solar Activities to the Earth's Atmosphere)
18 pages, 7021 KiB  
Article
Instability Compensation of Recording Interferometer in Phase-Sensitive OTDR
by Konstantin V. Stepanov, Andrey A. Zhirnov, Tatyana V. Gritsenko, Roman I. Khan, Kirill I. Koshelev, Cesare Svelto and Alexey B. Pnev
Sensors 2024, 24(11), 3338; https://doi.org/10.3390/s24113338 (registering DOI) - 23 May 2024
Abstract
In the paper, a new method of phase measurement error suppression in a phase-sensitive optical time domain reflectometer is proposed and experimentally proved. The main causes of phase measurement errors are identified and considered, such as the influence of the recording interferometer instabilities [...] Read more.
In the paper, a new method of phase measurement error suppression in a phase-sensitive optical time domain reflectometer is proposed and experimentally proved. The main causes of phase measurement errors are identified and considered, such as the influence of the recording interferometer instabilities and laser wavelength instability, which can cause inaccuracies in phase unwrapping. The use of a Mach–Zender interferometer made by 3 × 3 fiber couplers is proposed and tested to provide insensitivity to the recording interferometer and laser source instabilities. It is shown that using all three available photodetectors of the interferometer, instead of just one pair, achieves significantly better accuracy in the phase unwrapping. A novel compensation scheme for accurate phase measurements in a phase-sensitive optical time domain reflectometer is proposed, and a comparison of the measurement signals with or without such compensation is shown and discussed. The proposed method, using three photodetectors, allows for very good compensation of the phase measurement errors arising from common-mode noise from the interferometer and laser source, providing a significant improvement in signal detection. In addition, the method allows the tracking of slow temperature changes in the monitored fiber/object, which is not obtainable when using a simple low-pass filter for phase unwrapping error reduction, as is customary in several systems of this kind. Full article
(This article belongs to the Special Issue Feature Papers in Optical Sensors 2024)
Show Figures

Figure 1

20 pages, 4350 KiB  
Article
Research on Deployable Wings for MAVs Bioinspired by the Hind Wings of the Beetle Protaetia brevitarsis
by Jiyu Sun, Wenzhe Wang, Pengpeng Li and Zhijun Zhang
Biomimetics 2024, 9(6), 313; https://doi.org/10.3390/biomimetics9060313 (registering DOI) - 23 May 2024
Abstract
Deployable hind wings of beetles led to a bio-inspired idea to design deployable micro aerial vehicles (MAVs) to meet the requirement of miniaturization. In this paper, a bionic deployable wing (BD-W) model is designed based on the folding mechanism and elliptical wing vein [...] Read more.
Deployable hind wings of beetles led to a bio-inspired idea to design deployable micro aerial vehicles (MAVs) to meet the requirement of miniaturization. In this paper, a bionic deployable wing (BD-W) model is designed based on the folding mechanism and elliptical wing vein structure of the Protaetia brevitarsis hindwing, and its structural static and aerodynamic characteristics are analyzed by using ANSYS Workbench. Finally, the 3D-printed bionic deployable wing was tested in a wind tunnel and compared with simulation experiments to explore the effects of different incoming velocity, flapping frequency, and angle of attack on its aerodynamic characteristics, which resulted in the optimal combination of the tested parameters, among which, the incoming velocity is 3 m/s, the flapping frequency is 10 Hz, the angle of attack is 15°, and the lift-to-drag ratio of this parameter combination is 4.91. The results provide a theoretical basis and technical reference for the further development of bionic flapping wing for MAV applications. Full article
(This article belongs to the Special Issue Biomechanics and Biomimetics for Insect-Inspired MAVs)
Show Figures

Figure 1

21 pages, 479 KiB  
Article
Diversity of Institutional Investors’ Bidding Opinions in Shaping the Sustainability of IPO Performance
by Anqi Li, Xue Li, Jiayan Liu and Aochen Cao
Sustainability 2024, 16(11), 4418; https://doi.org/10.3390/su16114418 (registering DOI) - 23 May 2024
Abstract
In this study, we leverage a comprehensive dataset of over 3.8 million bid entries from institutional investors participating in China’s capital market to investigate the determinants of heterogeneous bidding behavior among these investors and the subsequent economic outcomes. We evaluate the sustainability of [...] Read more.
In this study, we leverage a comprehensive dataset of over 3.8 million bid entries from institutional investors participating in China’s capital market to investigate the determinants of heterogeneous bidding behavior among these investors and the subsequent economic outcomes. We evaluate the sustainability of initial public offering (IPO) performance through three interrelated metrics: post-IPO stock price performance, financial accounting performance, and environmental, social, and governance (ESG) performance. Our analysis reveals a pronounced positive association between the quality of firms’ pre-IPO and the recent reforms to the bookbuilding mechanism in China’s capital market, as well as the level of diversity in institutional investors’ bidding opinions. After accounting for these factors, we focus on the nexus between the diversity of bidding opinions and the sustainability of IPO performance. The empirical evidence indicates that a higher degree of diversity in bidding opinions is inversely related to firms’ post-IPO stock price performance, financial accounting performance, and ESG performance. Further mechanism tests suggest that this diversity leads to a depletion of medium- to long-term share price performance by intensifying market sentiment; impedes the enhancement of financial accounting performance by reducing the capital raised during the IPO; and negatively impacts ESG performance by constraining the firm’s ability to fulfill its corporate social responsibilities. These findings challenge the assumption that diversity of opinion is always beneficial. The insights gained from this research have significant implications for the sustainable growth strategies of listed companies in emerging markets. Full article
Show Figures

Figure 1

15 pages, 3406 KiB  
Article
Understanding the Liver’s Role in the Clearance of Aβ40
by Glen P. Lockwood, Nicholas J. Hunt, Maaike Kockx, Sun Woo Sophie Kang, David G. Le Couteur and Victoria C. Cogger
Livers 2024, 4(2), 253-267; https://doi.org/10.3390/livers4020018 (registering DOI) - 23 May 2024
Abstract
The clearance of peripheral beta amyloid (Aβ) is a potential target for the treatment of Alzheimer’s disease (AD). The liver has been implicated in the elimination of Aβ from the peripheral circulation. Here, the single-pass uptake of Aβ40 in perfused livers from young [...] Read more.
The clearance of peripheral beta amyloid (Aβ) is a potential target for the treatment of Alzheimer’s disease (AD). The liver has been implicated in the elimination of Aβ from the peripheral circulation. Here, the single-pass uptake of Aβ40 in perfused livers from young and old rats (6 to 10 rats per group) was investigated with the multiple indicator dilution technique. Aβ40 had volumes of distribution between those of the vascular marker Evans Blue and the extracellular marker sucrose. The hepatic extraction of Aβ40 was negligible, explained in part by the small permeability surface area products consistent with a high endothelial barrier to liver uptake. There were no substantial effects of age on any of these results. In vitro experiments with isolated hepatocytes and liver sinusoidal endothelial cells showed only very small amounts of Aβ uptake consistent with low intrinsic clearance. These results indicate that the hepatic clearance of Aβ is capacity-limited, explained by the low-permeability surface area products and hepatocyte uptake. However, this does not preclude an effect of aging in longer-term in vivo studies where age-related changes in liver blood flow and protein binding influence liver clearance. Full article
Show Figures

Figure 1

25 pages, 5632 KiB  
Article
Helical Gearbox Defect Detection with Machine Learning Using Regular Mesh Components and Sidebands
by Iulian Lupea, Mihaiela Lupea and Adrian Coroian
Sensors 2024, 24(11), 3337; https://doi.org/10.3390/s24113337 (registering DOI) - 23 May 2024
Abstract
The current paper presents helical gearbox defect detection models built from raw vibration signals measured using a triaxial accelerometer. Gear faults, such as localized pitting, localized wear on helical pinion tooth flanks, and low lubricant level, are under observation for three rotating velocities [...] Read more.
The current paper presents helical gearbox defect detection models built from raw vibration signals measured using a triaxial accelerometer. Gear faults, such as localized pitting, localized wear on helical pinion tooth flanks, and low lubricant level, are under observation for three rotating velocities of the actuator and three load levels at the speed reducer output. The emphasis is on the strong connection between the gear faults and the fundamental meshing frequency GMF, its harmonics, and the sidebands found in the vibration spectrum as an effect of the amplitude modulation (AM) and phase modulation (PM). Several sets of features representing powers on selected frequency bands or/and associated peak amplitudes from the vibration spectrum, and also, for comparison, time-domain and frequency-domain statistical feature sets, are proposed as predictors in the defect detection task. The best performing detection model, with a testing accuracy of 99.73%, is based on SVM (Support Vector Machine) with a cubic kernel, and the features used are the band powers associated with six GMF harmonics and two sideband pairs for all three accelerometer axes, regardless of the rotation velocities and the load levels. Full article
Show Figures

Figure 1

12 pages, 2013 KiB  
Article
Stable Isotope Hydrology of Karst Groundwaters in Romania
by Renata Feher, Carmen-Andreea Bădăluță, Traian Brad, Călin Drăgan, Virgil Drăgușin, Dragoș Ștefan Măntoiu, Aurel Perșoiu and Maria-Laura Tîrlă
Water 2024, 16(11), 1489; https://doi.org/10.3390/w16111489 (registering DOI) - 23 May 2024
Abstract
In this article we present the first investigation of the stable isotope composition of groundwater in Romania, East-Central Europe, with a focus on the karst areas. Our aim is twofold: (1) to provide a countrywide map with the distribution of stable oxygen and [...] Read more.
In this article we present the first investigation of the stable isotope composition of groundwater in Romania, East-Central Europe, with a focus on the karst areas. Our aim is twofold: (1) to provide a countrywide map with the distribution of stable oxygen and hydrogen isotope ratios in groundwater, and (2) to assess the recharge patterns of karst water. We collected more than 600 water samples from springs and wells across Romania for stable isotope analyses and monitored in detail the stable isotope composition of the waters as they pass through five cave systems. Our data show a spatial distribution of the stable isotope composition of the groundwater with low values in the mountainous area and high values in the surrounding lowlands and the central Transylvanian Depression. However, waters in karst areas induce departures from this distribution, resulting from the fast (hours to days) transfer of waters from high (ponor) to low (spring) altitudes. Water emerging from the karst springs has generally lower δ values than before sinking through the ponors, thus indicating a substantial contribution of winter recharge through diffuse infiltration and seepage. This contribution results in overall dilution of the water entering through ponors, likely resulting in changes in the chemical composition of the water and diluting potential pollutants. Our data call for careful separation between karst and non-karst spring/well waters, as indiscriminate common treatment might lead to erroneous interpretations. Full article
20 pages, 859 KiB  
Article
Local Influence for the Thin-Plate Spline Generalized Linear Model
by Germán Ibacache-Pulgar, Pablo Pacheco, Orietta Nicolis and Miguel Angel Uribe-Opazo
Axioms 2024, 13(6), 346; https://doi.org/10.3390/axioms13060346 (registering DOI) - 23 May 2024
Abstract
Thin-Plate Spline Generalized Linear Models (TPS-GLMs) are an extension of Semiparametric Generalized Linear Models (SGLMs), because they allow a smoothing spline to be extended to two or more dimensions. This class of models allows modeling a set of data in which it is [...] Read more.
Thin-Plate Spline Generalized Linear Models (TPS-GLMs) are an extension of Semiparametric Generalized Linear Models (SGLMs), because they allow a smoothing spline to be extended to two or more dimensions. This class of models allows modeling a set of data in which it is desired to incorporate the non-linear joint effects of some covariates to explain the variability of a certain variable of interest. In the spatial context, these models are quite useful, since they allow the effects of locations to be included, both in trend and dispersion, using a smooth surface. In this work, we extend the local influence technique for the TPS-GLM model in order to evaluate the sensitivity of the maximum penalized likelihood estimators against small perturbations in the model and data. We fit our model through a joint iterative process based on Fisher Scoring and weighted backfitting algorithms. In addition, we obtained the normal curvature for the case-weight perturbation and response variable additive perturbation schemes, in order to detect influential observations on the model fit. Finally, two data sets from different areas (agronomy and environment) were used to illustrate the methodology proposed here. Full article
(This article belongs to the Special Issue Mathematical Models and Simulations II)
21 pages, 1270 KiB  
Article
The Schwarzian Approach in Sturm–Liouville Problems
by Nektarios Vlahakis
Symmetry 2024, 16(6), 648; https://doi.org/10.3390/sym16060648 (registering DOI) - 23 May 2024
Abstract
A novel method for finding the eigenvalues of a Sturm–Liouville problem is developed. Following the minimalist approach, the problem is transformed to a single first-order differential equation with appropriate boundary conditions. Although the resulting equation is nonlinear, its form allows us to find [...] Read more.
A novel method for finding the eigenvalues of a Sturm–Liouville problem is developed. Following the minimalist approach, the problem is transformed to a single first-order differential equation with appropriate boundary conditions. Although the resulting equation is nonlinear, its form allows us to find the general solution by adding a second part to a particular solution. This splitting of the general solution into two parts involves the Schwarzian derivative: hence, the name of the approach. The eigenvalues that correspond to acceptable solutions can be found by requiring the second part to correct the asymptotically diverging behavior of the particular solution. The method can be applied to many different areas of physics, such as the Schrödinger equation in quantum mechanics and stability problems in fluid dynamics. Examples are presented. Full article
(This article belongs to the Special Issue Feature Papers in 'Physics' Section 2024)
Show Figures

Figure 1

20 pages, 4481 KiB  
Article
Improving Sag Resistance in Geopolymer Coatings Using Diatomite Filler: Effects on Rheological Properties and Early Hydration
by Yuan Hu, Zuquan Jin, Bo Pang, Zhantao Du, Xiangxiang Li and Yuxin Huang
Materials 2024, 17(11), 2516; https://doi.org/10.3390/ma17112516 (registering DOI) - 23 May 2024
Abstract
The reduction in the rheological parameters and dissolution rate of precursors in geopolymer coatings during early hydration significantly contributes to sagging. This study aims to improve the sag resistance of these coatings by incorporating diatomite filler. Rheological testing was conducted to assess the [...] Read more.
The reduction in the rheological parameters and dissolution rate of precursors in geopolymer coatings during early hydration significantly contributes to sagging. This study aims to improve the sag resistance of these coatings by incorporating diatomite filler. Rheological testing was conducted to assess the impact of diatomite and its concentration on the yield stress, plastic viscosity, and thixotropy of the geopolymer coatings. The results indicated that diatomite’s large specific surface area and high reactivity have a significant influence on the rheological parameters and early dissolution rate of precursors. With a diatomite concentration of 1.1%, the coating exhibited a yield stress of 2.749 Pa and a plastic viscosity of 0.921 Pa·s, maintaining stability, homogeneity, and no sagging at a thickness of 600 μm. Furthermore, the highly active SiO2 in diatomite participates in the secondary hydration reaction of the geopolymer materials led to the formation of substantial C-(A)-S-H gel. This gel enhances internal interconnectivity within the coating, thereby improving its rheological and mechanical properties. Full article
(This article belongs to the Section Construction and Building Materials)
19 pages, 8432 KiB  
Article
Design, Synthesis and Biological Evaluation of Novel Ketamine Derivatives as NMDAR Antagonists
by Shiyun Li, Bin Wen, Wei Zhao, Lulu Wang and Xingquan Chen
Molecules 2024, 29(11), 2459; https://doi.org/10.3390/molecules29112459 (registering DOI) - 23 May 2024
Abstract
Depression is a chronic, severe, and often life-threatening neurological disorder. It not only causes depression in patients and affects daily life but, in severe cases, may lead to suicidal behavior and have adverse effects on families and society. In recent years, it has [...] Read more.
Depression is a chronic, severe, and often life-threatening neurological disorder. It not only causes depression in patients and affects daily life but, in severe cases, may lead to suicidal behavior and have adverse effects on families and society. In recent years, it has been found that sub-anesthetic doses of ketamine have a rapid antidepressant effect on patients with treatment-resistant depression and can significantly reduce the suicidal tendencies of patients with major depressive disorder. Current studies suggest that ketamine may exert antidepressant effects by blocking NMDAR ion channels, but its anesthetic and psychotomimetic side effects limit its application. Here, we report efforts to design and synthesize a novel series of ketamine derivatives of NMDAR antagonists, among which compounds 23 and 24 have improved activity compared with ketamine, introducing a new direction for the development of rapid-acting antidepressant drugs. Full article
Show Figures

Figure 1

23 pages, 1890 KiB  
Article
A Long-Term Power Supply Risk Evaluation Method for China Regional Power System Based on Probabilistic Production Simulation
by Jianzu Hu, Yuefeng Wang, Fan Cheng and Hanqing Shi
Energies 2024, 17(11), 2515; https://doi.org/10.3390/en17112515 (registering DOI) - 23 May 2024
Abstract
To qualify the risk of extreme weather events for power supply security during the long-term power system transformation process, this paper proposes a risk probability evaluation method based on probabilistic production simulation. Firstly, the internal relationship of extreme weather intensity and duration is [...] Read more.
To qualify the risk of extreme weather events for power supply security during the long-term power system transformation process, this paper proposes a risk probability evaluation method based on probabilistic production simulation. Firstly, the internal relationship of extreme weather intensity and duration is depicted using the copula function, and the influences of extreme weather on power security are described using the guaranteed power output ability coefficient, which can provide the extreme scenario basis for probabilistic production simulation. Then, a probabilistic production simulation method is proposed, which includes a typical-year scenario and extreme weather events. Meanwhile, an index system is proposed to qualify the power security level, which applies the loss of load expectation (LOLE) and time of loss of load expectation (TOLE) under different scenarios and other indices to reveal the long-term power security trend. Finally, the long-term power supply risks for the Yunnan provincial power system are analyzed using the proposed method, validating that the proposed method is capable of characterizing the influences of extreme weather on power security. The security level of different long-term power transformation schemes is evaluated. Full article
12 pages, 296 KiB  
Article
On S-2-Prime Ideals of Commutative Rings
by Sanem Yavuz, Bayram Ali Ersoy, Ünsal Tekir and Ece Yetkin Çelikel
Mathematics 2024, 12(11), 1636; https://doi.org/10.3390/math12111636 (registering DOI) - 23 May 2024
Abstract
Prime ideals and their generalizations are crucial in numerous research areas, particularly in commutative algebra. The concept of generalization of prime ideals begins with the study of weakly prime ideals. Since then, subsequent works aimed at expanding this concept into more generalized forms. [...] Read more.
Prime ideals and their generalizations are crucial in numerous research areas, particularly in commutative algebra. The concept of generalization of prime ideals begins with the study of weakly prime ideals. Since then, subsequent works aimed at expanding this concept into more generalized forms. Among these, S-prime ideals and 2-prime ideals have reaped attention recently. This paper aims to characterize S-2-prime ideals, which serve as a generalization encompassing both 2-prime ideals and S-prime ideals. To accomplish this objective, we construct an ideal which distinct from a multiplicatively closed subset with the help of commutative rings. We investigate the localization and the S-2-prime avoidance lemma in commutative rings. Furthermore, we explore the properties of this class of ideals in trivial ring extensions and amalgamated algebras along an ideal. We delve into S-properties for compactly packedness, compactly 2-packedness and coprimely packedness in trivial ring extentions. Moreover, this notion of ideals helps us to indicate that many results stated in S-prime ideals and 2-prime ideals can be readily expanded to the framework of S-2-prime ideals. Supporting examples also highlight a significant distinction between S-2-prime ideals and stated ideals. Full article
(This article belongs to the Section Algebra, Geometry and Topology)
22 pages, 5378 KiB  
Article
Building Integrated Photovoltaics (BIPV): Analysis of the Technological Transfer Process and Innovation Dynamics in the Swiss Building Sector
by Pierluigi Bonomo and Francesco Frontini
Buildings 2024, 14(6), 1510; https://doi.org/10.3390/buildings14061510 (registering DOI) - 23 May 2024
Abstract
Solar has confirmed its dominance among all power generation technologies, and along with the demand for zero-emission buildings, Photovoltaics (PV) is contributing to transforming the building skin. More than 200 products for Building Integrated Photovoltaics (BIPV) are commercialized nowadays in the EU market. [...] Read more.
Solar has confirmed its dominance among all power generation technologies, and along with the demand for zero-emission buildings, Photovoltaics (PV) is contributing to transforming the building skin. More than 200 products for Building Integrated Photovoltaics (BIPV) are commercialized nowadays in the EU market. However, only 1–3% of all PV installations are BIPV due to the weak penetration in the construction sector. At the state of the art, the sector lacks a specific analysis from a construction technology perspective, describing the dynamics and the traits that BIPV innovation articulates on construction and architectural processes. The authors, elaborating a new model from the building technology sector to explore the relationship between PV technology and architectural innovation, aim to identify the main principles, forms, and approaches that describe the structural organization of the “integrability” concept of PV in buildings. This study applies the method to a database of 233 real buildings located in Switzerland, a unique country leading with a 10% BIPV rate on PV installations documented between the years 1997 and 2023. The novel findings of the research suggest the definition of the levels of innovation and the reference traits of the innovative process of BIPV in the Swiss construction sector, which can also be used in other practical applications and contexts. The results of the paper are expected to impact both the scientific academy and the key players from the construction sector, encouraging the adoption of an integrated research and design approach to revolutionize the energy role of building skins with PV. Full article
(This article belongs to the Section Building Energy, Physics, Environment, and Systems)
Show Figures

Figure 1

24 pages, 1232 KiB  
Article
Synthetic Aperture Radar Image Change Detection Based on Principal Component Analysis and Two-Level Clustering
by Liangliang Li, Hongbing Ma, Xueyu Zhang, Xiaobin Zhao, Ming Lv and Zhenhong Jia
Remote Sens. 2024, 16(11), 1861; https://doi.org/10.3390/rs16111861 (registering DOI) - 23 May 2024
Abstract
Synthetic aperture radar (SAR) change detection provides a powerful tool for continuous, reliable, and objective observation of the Earth, supporting a wide range of applications that require regular monitoring and assessment of changes in the natural and built environment. In this paper, we [...] Read more.
Synthetic aperture radar (SAR) change detection provides a powerful tool for continuous, reliable, and objective observation of the Earth, supporting a wide range of applications that require regular monitoring and assessment of changes in the natural and built environment. In this paper, we introduce a novel SAR image change detection method based on principal component analysis and two-level clustering. First, two difference images of the log-ratio and mean-ratio operators are computed, then the principal component analysis fusion model is used to fuse the two difference images, and a new difference image is generated. To incorporate contextual information during the feature extraction phase, Gabor wavelets are used to obtain the representation of the difference image across multiple scales and orientations. The maximum magnitude across all orientations at each scale is then concatenated to form the Gabor feature vector. Following this, a cascading clustering algorithm is developed within this discriminative feature space by merging the first-level fuzzy c-means clustering with the second-level neighbor rule. Ultimately, the two-level combination of the changed and unchanged results produces the final change map. Five SAR datasets are used for the experiment, and the results show that our algorithm has significant advantages in SAR change detection. Full article
(This article belongs to the Section Remote Sensing Image Processing)
15 pages, 3561 KiB  
Article
Exploring Pijuayo (Bactris gasipaes) Pulp and Peel Flours as Fat Replacers in Burgers: A Multivariate Study on Physicochemical and Sensory Traits
by Alex Y. Llatas, Heiner Guzmán, Fernando Tello, Roger Ruiz, Jessy Vásquez, Grisel Chiroque, Jhony Mayta-Hancco, Melina L. M. Cruzado-Bravo, Hubert Arteaga, Erick Saldaña and Juan D. Rios-Mera
Foods 2024, 13(11), 1619; https://doi.org/10.3390/foods13111619 (registering DOI) - 23 May 2024
Abstract
Meat products are known for their lipid profile rich in saturated fats and cholesterol, and also for the formation of oxidation compounds; therefore, a reduction in animal fat may result in a product less harmful to health. Pijuayo is an Amazon fruit known [...] Read more.
Meat products are known for their lipid profile rich in saturated fats and cholesterol, and also for the formation of oxidation compounds; therefore, a reduction in animal fat may result in a product less harmful to health. Pijuayo is an Amazon fruit known for its nutritional properties, such as its fiber and lipid content. For these reasons, it is an attractive fruit to replace animal fat in meat products. The present work used pijuayo pulp and peel flours to partially replace animal fat in beef-based burgers at 25% and 50% levels, considering sensory and physicochemical outcomes evaluated by Principal Component Analysis (PCA), Correspondence Analysis (CA) and Multiple Factor Analysis (MFA). Pijuayo flour affected the physicochemical characteristics evaluated by PCA, where the samples with greater fat replacement were characterized by a high carbohydrate content and instrumental yellowness. The minimal fat replacement did not abruptly affect the PCA’s instrumental texture and color, proximal composition, yield properties, and lipid oxidation. The overall liking was greater in the 25% fat reduction treatments, even greater than the control, in which positive sensory attributes for liking were highlighted for those treatments. A small segment of consumers (11% of total consumers) preferred the treatment with greater replacement of fat with pijuayo peel flour, which these consumers tended to characterize as seasoned. However, this treatment had the lowest liking. The MFA showed that the sensory characteristics tender and tasty were strongly correlated with overall liking and were highlighted in the samples of 25% fat reduction, suggesting that the pijuayo improves the tenderness and flavor of reduced-fat burgers. Other inclusion levels between 25% and 50% of fat replacement could be explored, and optimization studies are needed. In addition, the sensory characteristics and flavor-enhancing compounds of the fruit, as well as the nutritional aspects of the inclusion of pijuayo, should be studied, such as the fatty acid profile. These characteristics will be informative to explore pijuayo as a fat replacer at a pilot scale and industrial scale. Full article
(This article belongs to the Section Meat)
Show Figures

Figure 1

24 pages, 9194 KiB  
Article
Life Cycle Assessment of Plant-Based vs. Beef Burgers: A Case Study in the UK
by Meshach Tang, Taghi Miri, Fakhteh Soltani, Helen Onyeaka and Zainab T. Al-Sharify
Sustainability 2024, 16(11), 4417; https://doi.org/10.3390/su16114417 (registering DOI) - 23 May 2024
Abstract
As the world attempts to decarbonise the food industry and limit greenhouse gas (GHG) emissions, plant-based meat analogues (PBMAs) have emerged as a sustainable alternative to traditional meat. The objective of this study is to assess the environmental impacts of PBMAs compared to [...] Read more.
As the world attempts to decarbonise the food industry and limit greenhouse gas (GHG) emissions, plant-based meat analogues (PBMAs) have emerged as a sustainable alternative to traditional meat. The objective of this study is to assess the environmental impacts of PBMAs compared to traditional beef burgers, aiming to address the research gap in the life cycle assessments (LCAs) of publicly available PBMA recipes. Utilising a cradle-to-fork system boundary, this research conducted a rigorous LCA on a 100 g plant-based burger patty and its beef burger (BB) counterpart, each produced in the UK but sourced from different global locations. The results demonstrated that the plant-based burger had significantly lower environmental impacts across several categories, including a 65% reduction in global warming potential and a 45% reduction in water consumption. A simple extrapolation illustrated that if the UK population switched from beef to meat analogue patties, 3 million tonnes of CO2e could be saved annually, corresponding to 0.74% of the country’s yearly territorial GHG emissions. Scenario analyses displayed how the environmental impact of the MA patty remained stable regardless of changes in exportation, ingredient origin or soy protein sourcing. Moreover, a sensitivity analysis conducted with an alternative characterisation method corroborated the initial findings, whilst uncertainty analysis ensured that nearly all of the conclusions generated from the original comparison were robust. Future studies should conduct LCAs on PBMA patties with commercial recipes using varied plant-based sources, as well as fully understanding any potential health implications of long-term PBMA consumption. Full article
Show Figures

Graphical abstract

23 pages, 4627 KiB  
Article
An Enhanced Indoor Three-Dimensional Localization System with Sensor Fusion Based on Ultra-Wideband Ranging and Dual Barometer Altimetry
by Le Bao, Kai Li, Joosun Lee, Wenbin Dong, Wenqi Li, Kyoosik Shin and Wansoo Kim
Sensors 2024, 24(11), 3341; https://doi.org/10.3390/s24113341 (registering DOI) - 23 May 2024
Abstract
Accurate three-dimensional (3D) localization within indoor environments is crucial for enhancing item-based application services, yet current systems often struggle with localization accuracy and height estimation. This study introduces an advanced 3D localization system that integrates updated ultra-wideband (UWB) sensors and dual barometric pressure [...] Read more.
Accurate three-dimensional (3D) localization within indoor environments is crucial for enhancing item-based application services, yet current systems often struggle with localization accuracy and height estimation. This study introduces an advanced 3D localization system that integrates updated ultra-wideband (UWB) sensors and dual barometric pressure (BMP) sensors. Utilizing three fixed UWB anchors, the system employs geometric modeling and Kalman filtering for precise tag 3D spatial localization. Building on our previous research on indoor height measurement with dual BMP sensors, the proposed system demonstrates significant improvements in data processing speed and stability. Our enhancements include a new geometric localization model and an optimized Kalman filtering algorithm, which are validated by a high-precision motion capture system. The results show that the localization error is significantly reduced, with height accuracy of approximately ±0.05 m, and the Root Mean Square Error (RMSE) of the 3D localization system reaches 0.0740 m. The system offers expanded locatable space and faster data output rates, delivering reliable performance that supports advanced applications requiring detailed 3D indoor localization. Full article
Show Figures

Figure 1

21 pages, 2076 KiB  
Article
Solvent Bar Microextraction Method Based on a Natural Deep Eutectic Solvent and Multivariate Optimization for Determination of Steroid Hormones in Urine and Water
by Nabil N. AL-Hashimi, Husam Abed Alfattah, Musa I. El-Barghouthi, Amjad H. El-Sheikh, Hanan M. Ale-nezi, Mahmoud S. Sunjuk and Khairi M. Fahelelbom
Appl. Sci. 2024, 14(11), 4438; https://doi.org/10.3390/app14114438 (registering DOI) - 23 May 2024
Abstract
Steroid hormones may pose potential risks to both human health and wildlife, primarily through the consumption of medication or polluted food and water; efforts are being made to monitor their levels in the human body and regulate and minimize their releases to the [...] Read more.
Steroid hormones may pose potential risks to both human health and wildlife, primarily through the consumption of medication or polluted food and water; efforts are being made to monitor their levels in the human body and regulate and minimize their releases to the environment. In this study, a simple and environmentally friendly sample preparation method was developed to simultaneously determine three steroid hormones in urine and water samples. A monoterpene (menthol) and a fatty acid (lauric acid) were combined in various ratios to form a hydrophobic deep eutectic (HDE) solvent as an extraction solvent in solvent bar microextraction (SBME). Using a univariate strategy, a menthol-to-lauric acid HDE ratio of 4:1 and a pH 7 of the sample solution resulted in the highest extraction efficiency (EE%) of the selected steroids. The computational methods have been employed to predict a 4:1 HDE interaction with chosen steroids. Additionally, chemometric approaches suggested that the optimal extraction conditions involved HDEs as extract solvent confined within three SBME devices directly immersed into a 20 mL sample solution with a 30 min extraction time, followed by ultrasonication within 200 μL of elution solvent for a 5 min elution time. Under optimized conditions, the method calibration graph for the spiked selected steroids in the water and urine samples showed good linearity with R2 ≥ 0.994 with limits of detection/quantification lower than 0.40/1.35 μg L−1 and repeatability/reproducibility (RSD%, n = 5) lower than 5.09/7.11. The developed method allows a safe, rapid, and reliable analysis of three steroid hormones in human urine and water samples without using toxic volatile organic solvents. Full article

Open Access Journals

Browse by Indexing Browse by Subject Selected Journals
Back to TopTop