The 2023 MDPI Annual Report has
been released!
 
11 pages, 382 KiB  
Article
A Study of Environmental Organizations in Puerto Rico Advocating for Social and Environmental Justice
by Clara E. Rodriguez and Carmen Collins
Soc. Sci. 2024, 13(5), 260; https://doi.org/10.3390/socsci13050260 (registering DOI) - 11 May 2024
Abstract
After Hurricane Maria devastated Puerto Rico, we wanted to determine how the islanders viewed environmental organizations as part of an effort to understand the relationships between attitudes, institutions, and environmental and social justice issues. As a category 5 hurricane, Hurricane Maria was one [...] Read more.
After Hurricane Maria devastated Puerto Rico, we wanted to determine how the islanders viewed environmental organizations as part of an effort to understand the relationships between attitudes, institutions, and environmental and social justice issues. As a category 5 hurricane, Hurricane Maria was one of the strongest to hit Puerto Rico. Yet, the US mainstream media coverage of this and other environmental issues was lacking. From a total of 90 environmental organizations in Puerto Rico, we surveyed 19 that were active in the southwest of the island. We asked: (1) How do local people view environmental and social justice issues and (2) given their organizations’ efforts to deal with these issues, what are their successes? To address these questions, we developed a survey in English and Spanish and conducted personal and online interviews with 30 relevant individuals. Their most successful outcomes included: (1) educating and creating greater awareness of environmental issues; (2) introducing environmental changes into their communities; and (3) becoming and surviving as economically sustainable organizations. The results inform our understanding between environmental organizations and social and environmental justice in Puerto Rico and more broadly, because the organizations surveyed are at the center of fighting climate change and achieving environmental justice. Full article
(This article belongs to the Special Issue Social and Environmental Justice)
13 pages, 815 KiB  
Article
Characterizing Spatial and Temporal Variations in N2O Emissions from Dairy Manure Management in China Based on IPCC Methodology
by Bin Hu, Lijie Zhang, Chao Liang, Xiao Yang, Zhengxiang Shi and Chaoyuan Wang
Agriculture 2024, 14(5), 753; https://doi.org/10.3390/agriculture14050753 (registering DOI) - 11 May 2024
Abstract
The emission factor method (Tier 1) recommended by the Intergovernmental Panel on Climate Change (IPCC) is commonly used to estimate greenhouse gas (GHG) emissions from livestock and poultry farms. However, the estimation accuracy may vary due to practical differences in manure management across [...] Read more.
The emission factor method (Tier 1) recommended by the Intergovernmental Panel on Climate Change (IPCC) is commonly used to estimate greenhouse gas (GHG) emissions from livestock and poultry farms. However, the estimation accuracy may vary due to practical differences in manure management across China. The objectives of this study were to estimate the direct and indirect nitrous oxide (N2O) emissions from dairy manure management between 1990 and 2021 in China and characterize its spatial and temporal variations following IPCC guideline Tier 2. The N2O emission factor (EF) of dairy cow manure management systems was determined at the national level and regional level as well. The results showed that the national cumulative N2O emission of manure management from 1990 to 2021 was 113.1million tons of CO2 equivalent, ranging from 90.3 to 135.9 million tons with an uncertainty of ±20.2%. The annual EF was 0.021 kg N2O-N (kg N)−1 for total emissions, while it was 0.014 kg N2O-N (kg N)−1 for direct emissions. The proportions of N2O emissions in North China, Northeast China, East China, Central and Southern China, Southwest China and Northwest China were 32.3%, 18.6%, 11.4%, 5.8%, 6.1% and 25.8%, respectively. In addition, N2O emissions varied among farms in different scales. The respective proportions of total N2O emissions from small-scale and large-scale farms were 64.8% and 35.2% in the past three decades. With the improvement in farm management and milk production efficiency, the N2O emissions per unit mass of milk decreased from 0.77 × 10−3 kg to 0.48 × 10−3 kg in 1990–2021. This study may provide important insights into compiling a GHG emission inventory and developing GHG emission reduction strategies for the dairy farming system in China. Full article
(This article belongs to the Section Ecosystem, Environment and Climate Change in Agriculture)
16 pages, 4877 KiB  
Article
Channel Knowledge Map Construction Based on a UAV-Assisted Channel Measurement System
by Yanheng Qiu, Xiaomin Chen, Kai Mao, Xuchao Ye, Hanpeng Li, Farman Ali, Yang Huang and Qiuming Zhu
Drones 2024, 8(5), 191; https://doi.org/10.3390/drones8050191 (registering DOI) - 11 May 2024
Abstract
With the fast development of unmanned aerial vehicles (UAVs), reliable UAV communication is becoming increasingly vital. The channel knowledge map (CKM) is a crucial bridge connecting the environment and the propagation channel that may visually depict channel characteristics. This paper presents a comprehensive [...] Read more.
With the fast development of unmanned aerial vehicles (UAVs), reliable UAV communication is becoming increasingly vital. The channel knowledge map (CKM) is a crucial bridge connecting the environment and the propagation channel that may visually depict channel characteristics. This paper presents a comprehensive scheme based on a UAV-assisted channel measurement system for constructing the CKM in real-world scenarios. Firstly, a three-dimensional (3D) CKM construction scheme for real-world scenarios is provided, which involves channel knowledge extraction, mapping, and completion. Secondly, an algorithm of channel knowledge extraction and completion is proposed. The sparse channel knowledge is extracted based on the sliding correlation and constant false alarm rate (CFAR) approaches. The 3D Kriging interpolation is used to complete the sparse channel knowledge. Finally, a UAV-assisted channel measurement system is developed and CKM measurement campaigns are conducted in campus and farmland scenarios. The path loss (PL) and root mean square delay spread (RMS-DS) are measured at different heights to determine CKMs. The measured and analyzed results show that the proposed construction scheme can effectively and accurately construct the CKMs in real-world scenarios. Full article
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13 pages, 3676 KiB  
Communication
C(sp)-C(sp) Lever-Based Targets of Orientational Chirality: Design and Asymmetric Synthesis
by Ting Xu, Jia-Yin Wang, Yu Wang, Shengzhou Jin, Yao Tang, Sai Zhang, Qingkai Yuan, Hao Liu, Wenxin Yan, Yinchun Jiao, Xiao-Liang Yang and Guigen Li
Molecules 2024, 29(10), 2274; https://doi.org/10.3390/molecules29102274 (registering DOI) - 11 May 2024
Abstract
In this study, the design and asymmetric synthesis of a series of chiral targets of orientational chirality were conducted by taking advantage of N-sulfinylimine-assisted nucleophilic addition and modified Sonogashira catalytic coupling systems. Orientational isomers were controlled completely using alkynyl/alkynyl levers [C(sp)-C(sp) axis] [...] Read more.
In this study, the design and asymmetric synthesis of a series of chiral targets of orientational chirality were conducted by taking advantage of N-sulfinylimine-assisted nucleophilic addition and modified Sonogashira catalytic coupling systems. Orientational isomers were controlled completely using alkynyl/alkynyl levers [C(sp)-C(sp) axis] with absolute configuration assignment determined by X-ray structural analysis. The key structural element of the resulting orientational chirality is uniquely characterized by remote through-space blocking. Forty examples of multi-step synthesis were performed, with modest to good yields and excellent orientational selectivity. Several chiral orientational amino targets are attached with scaffolds of natural and medicinal products, showing potential pharmaceutical and medical applications in the future. Full article
(This article belongs to the Section Organic Chemistry)
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90 pages, 46719 KiB  
Systematic Review
IoT Solutions with Artificial Intelligence Technologies for Precision Agriculture: Definitions, Applications, Challenges, and Opportunities
by Elisha Elikem Kofi Senoo, Lia Anggraini, Jacqueline Asor Kumi, Luna Bunga Karolina, Ebenezer Akansah, Hafeez Ayo Sulyman, Israel Mendonça and Masayoshi Aritsugi
Electronics 2024, 13(10), 1894; https://doi.org/10.3390/electronics13101894 (registering DOI) - 11 May 2024
Abstract
The global agricultural sector confronts significant obstacles such as population growth, climate change, and natural disasters, which negatively impact food production and pose a threat to food security. In response to these challenges, the integration of IoT and AI technologies emerges as a [...] Read more.
The global agricultural sector confronts significant obstacles such as population growth, climate change, and natural disasters, which negatively impact food production and pose a threat to food security. In response to these challenges, the integration of IoT and AI technologies emerges as a promising solution, facilitating data-driven decision-making, optimizing resource allocation, and enhancing monitoring and control systems in agricultural operations to address these challenges and promote sustainable farming practices. This study examines the intersection of IoT and AI in precision agriculture (PA), aiming to provide a comprehensive understanding of their combined impact and mutually reinforcing relationship. Employing a systematic literature review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, we explore the synergies and transformative potential of integrating IoT and AI in agricultural systems. The review also aims to identify present trends, challenges, and opportunities in utilizing IoT and AI in agricultural systems. Diverse forms of agricultural practices are scrutinized to discern the applications of IoT and AI systems. Through a critical analysis of existing literature, this study contributes to a deeper understanding of how the integration of IoT and AI technologies can revolutionize PA, resulting in improved efficiency, sustainability, and productivity in the agricultural sector. Full article
15 pages, 5573 KiB  
Article
Axial Tensile Ultimate Strength of an Unbonded Flexible Riser Based on a Numerical Method
by Dongya Li, Wanchao Jiang, Qingqing Xing and Qingsheng Liu
Materials 2024, 17(10), 2286; https://doi.org/10.3390/ma17102286 (registering DOI) - 11 May 2024
Abstract
Unbonded flexible risers consist of several helical and cylindrical layers, which can undergo large bending deformation and can be installed to different configurations to adapt to harsh marine environments, and is a key equipment in transporting oil and gas resources from Ultra Deep [...] Read more.
Unbonded flexible risers consist of several helical and cylindrical layers, which can undergo large bending deformation and can be installed to different configurations to adapt to harsh marine environments, and is a key equipment in transporting oil and gas resources from Ultra Deep Waters (UDWs) to offshore platforms. The helical interlayer of an unbonded flexible riser makes the structural behavior difficult to predict. In this paper, the axial tensile behavior and the axial tensile ultimate strength of an unbonded flexible riser are studied based on a typical 2.5-inch eight-layer unbonded flexible riser model, and verified through a theoretical method considering the contact between adjacent layers. First, the balance equation of separate layers is deduced by a functional principle, and then the overall theoretical model of an unbonded flexible riser is established considering the geometric relationship between adjacent layers. Then, the numerical model considering the detailed geometric properties of an unbonded flexible riser is established to simulate the axial tensile behavior. Finally, after being verified through the experimental results, the axial tensile stiffness and axial tensile strength of an unboned flexible riser considering the elasticity of the tensile armor layer are studied using the proposed two methods. Additionally, the effect of frictional coefficients is conducted. The numerical and theoretical results show good agreement with the test results, and the friction between adjacent layers would increase the axial tensile stiffness of an unbonded flexible riser. Full article
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17 pages, 293 KiB  
Article
Multivariate and Matrix-Variate Logistic Models in the Real and Complex Domains
by A. M. Mathai
Stats 2024, 7(2), 445-461; https://doi.org/10.3390/stats7020027 (registering DOI) - 11 May 2024
Abstract
Several extensions of the basic scalar variable logistic density to the multivariate and matrix-variate cases, in the real and complex domains, are given where the extended forms end up in extended zeta functions. Several cases of multivariate and matrix-variate Bayesian procedures, in the [...] Read more.
Several extensions of the basic scalar variable logistic density to the multivariate and matrix-variate cases, in the real and complex domains, are given where the extended forms end up in extended zeta functions. Several cases of multivariate and matrix-variate Bayesian procedures, in the real and complex domains, are also given. It is pointed out that there are a range of applications of Gaussian and Wishart-based matrix-variate distributions in the complex domain in multi-look data from radar and sonar. It is hoped that the distributions derived in this paper will be highly useful in such applications in physics, engineering, statistics and communication problems, because, in the real scalar case, a logistic model is seen to be more appropriate compared to a Gaussian model in many industrial applications. Hence, logistic-based multivariate and matrix-variate distributions, especially in the complex domain, are expected to perform better where Gaussian and Wishart-based distributions are currently used. Full article
31 pages, 3284 KiB  
Article
Epigenetic Modulation of GPER Expression in Gastric and Colonic Smooth Muscle of Male and Female Non-Obese Diabetic (NOD) Mice: Insights into H3K4me3 and H3K27ac Modifications
by Juanita C. Hixon, Jatna I. Rivas Zarete, Jason White, Mariline Hilaire, Aliyu Muhammad, Abdurrahman Pharmacy Yusuf, Benjamin Adu-Addai, Clayton C. Yates and Sunila Mahavadi
Int. J. Mol. Sci. 2024, 25(10), 5260; https://doi.org/10.3390/ijms25105260 (registering DOI) - 11 May 2024
Abstract
Type 1 diabetes (T1D) affects gastrointestinal (GI) motility, favoring gastroparesis, constipation, and fecal incontinence, which are more prevalent in women. The mechanisms are unknown. Given the G-protein-coupled estrogen receptor’s (GPER) role in GI motility, we investigated sex-related diabetes-induced epigenetic changes in GPER. We [...] Read more.
Type 1 diabetes (T1D) affects gastrointestinal (GI) motility, favoring gastroparesis, constipation, and fecal incontinence, which are more prevalent in women. The mechanisms are unknown. Given the G-protein-coupled estrogen receptor’s (GPER) role in GI motility, we investigated sex-related diabetes-induced epigenetic changes in GPER. We assessed GPER mRNA and protein expression levels using qPCR and Western blot analyses, and quantified the changes in nuclear DNA methyltransferases and histone modifications (H3K4me3, H3Ac, and H3K27Ac) by ELISA kits. Targeted bisulfite and chromatin immunoprecipitation assays were used to evaluate DNA methylation and histone modifications around the GPER promoter by chromatin immunoprecipitation assays in gastric and colonic smooth muscle tissues of male and female control (CTR) and non-obese diabetic (NOD) mice. GPER expression was downregulated in NOD, with sex-dependent variations. In the gastric smooth muscle, not in colonic smooth muscle, downregulation coincided with differences in methylation ratios between regions 1 and 2 of the GPER promoter of NOD. DNA methylation was higher in NOD male colonic smooth muscle than in NOD females. H3K4me3 and H3ac enrichment decreased in NOD gastric smooth muscle. H3K4me3 levels diminished in the colonic smooth muscle of NOD. H3K27ac levels were unaffected, but enrichment decreased in NOD male gastric smooth muscle; however, it increased in the NOD male colonic smooth muscle and decreased in the female NOD colonic smooth muscle. Male NOD colonic smooth muscle exhibited decreased H3K27ac levels, not female, whereas female NOD colonic smooth muscle demonstrated diminished enrichment of H3ac at the GPER promoter, contrary to male NOD. Sex-specific epigenetic mechanisms contribute to T1D-mediated suppression of GPER expression in the GI tract. These insights advance our understanding of T1D complications and suggest promising avenues for targeted therapeutic interventions. Full article
(This article belongs to the Special Issue The Role of Estrogen Receptors in Health and Diseases)
27 pages, 3320 KiB  
Article
Characteristics and Reservoir Development Model of the Unconformity Caused by Huaiyuan Movement in Bohai Bay Basin, China: A Case Study of Chengdao-Zhuanghai Buried Hill in Jiyang Depression
by Ruijuan Liu, Guozhi Wang, Yongshi Wang, Xuefeng Hao, Feng Qin, Xianxu Fang, Wei Meng and Gang Liu
J. Mar. Sci. Eng. 2024, 12(5), 804; https://doi.org/10.3390/jmse12050804 (registering DOI) - 11 May 2024
Abstract
It is beneficial in terms of the theoretical significance and application prospects to define the structure and reservoir development model of the lower Paleozoic unconformity in the Jiyang Depression of Bohai Bay Basin, China, for oil and gas exploration of unconformity in carbonate [...] Read more.
It is beneficial in terms of the theoretical significance and application prospects to define the structure and reservoir development model of the lower Paleozoic unconformity in the Jiyang Depression of Bohai Bay Basin, China, for oil and gas exploration of unconformity in carbonate strata. Geological and geochemical evidence shows that a regional unconformity formed during the Huaiyuan Movement in the lower Paleozoic strata of the Jiyang Depression. Along the top of the regional unconformity between the Yeli Liangjiashan Formation and Fengshan Formation, various types of karst breccia have developed, showing prominent characteristics of development and vertical karst zonation. The paleokarst zone can be divided into the vadose zone and the underflow zone, and there are apparent differences between the two zones in terms of the mode of karst activity and type of reservoir space. Primitive sedimentary microfacies, dolomitization, and supergene karstification controlled the reservoirs of the Fengshan Formation and Yeli-Liangjiashan Formation. There are significant differences in the original physical properties due to the differences in the original sedimentary microfacies. The pore development of granular dolomite of high-energy beach facies has the best reservoir performance. In the later period, the superposition of dolomitization and supergene karstification resulted in apparent differences in karst development mode, development intensity, reservoir type, and reservoir physical properties. Among them, the granular dolomite reservoir has the best physical properties and has developed a cavity-type reservoir that has a planar distribution along an unconformity surface. Full article
20 pages, 959 KiB  
Article
The Impact of CSI SEEE Carbon Neutral Index Launched on Order Aggressiveness
by Zihuang Huang, Xiaoyu Zhang and Kaifeng Li
J. Risk Financial Manag. 2024, 17(5), 198; https://doi.org/10.3390/jrfm17050198 (registering DOI) - 11 May 2024
Abstract
In the context of carbon peaking and carbon neutrality goals, in order to clarify the investment direction for investors, China Securities Index Co., Ltd. (CSI) has collaborated with the Shanghai Environmental Energy Exchange to develop the CSI SEEE Carbon Neutral Index (CSCNI), which [...] Read more.
In the context of carbon peaking and carbon neutrality goals, in order to clarify the investment direction for investors, China Securities Index Co., Ltd. (CSI) has collaborated with the Shanghai Environmental Energy Exchange to develop the CSI SEEE Carbon Neutral Index (CSCNI), which has also played a leading role in the subsequent preparation of the Green Finance Index. The launch of this index has sparked research interest among scholars in stimulating investor order aggressiveness. This study employs event study methodology to examine the impact of the CSCNI launch on order aggressiveness. The sample companies are categorized into two groups: deep low-carbon and high-carbon reduction, with a focus on studying buy and sale order aggressiveness. The results indicate that the launch of CSCNI has mobilized order aggressiveness but has led to a negative stock price effect as investors anticipate an increase in environmental costs for the sample companies. Furthermore, we reveal that the long-term growth potential of the deep low-carbon field is more promising compared to the high-carbon reduction sector, making stocks in the deep low-carbon field more attractive. The launch of CSCNI has shown contrasting effects on the buy and sale order aggressiveness of investors, with the impact of the index announcement being more significant on the sample companies. This research provides valuable insights for evaluating the impact of green finance indices and contributes to the understanding of internal mechanisms. It provides an important reference for financial regulators to evaluate the development of the current green index. At the same time, it expands the domestic research on order aggressiveness, which studies the action mechanism of the stock price effect of the green stock index from the perspective of order aggressiveness. Full article
(This article belongs to the Special Issue Advances in Macroeconomics and Financial Markets)
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21 pages, 1902 KiB  
Article
Quality Assessment of Loquat under Different Preservation Methods Based on Physicochemical Indicators, GC–MS and Intelligent Senses
by Mingfeng Qiao, Siyue Luo, Zherenyongzhong Z., Xuemei Cai, Xinxin Zhao, Yuqin Jiang and Baohe Miao
Horticulturae 2024, 10(5), 499; https://doi.org/10.3390/horticulturae10050499 (registering DOI) - 11 May 2024
Abstract
To explore the effects of different preservation methods on the quality of loquat after fresh-keeping treatment, various preservation techniques were employed. These included natural preservation (NP), vacuum freezing preservation (VFP), vacuum at room temperature preservation (VP) and freezing preservation (FP). The quality assessment [...] Read more.
To explore the effects of different preservation methods on the quality of loquat after fresh-keeping treatment, various preservation techniques were employed. These included natural preservation (NP), vacuum freezing preservation (VFP), vacuum at room temperature preservation (VP) and freezing preservation (FP). The quality assessment involved analyzing the effects of these preservation methods using physicochemical indexes, a colorimeter, an electronic nose (E-nose), an electronic tongue (E-tongue) and gas chromatography–mass spectrometry (GC–MS). The results showed minor differences in loquat quality under different preservation methods, with sensory scores ranging from 55 to 78 and ΔE values ranging from 11.92 to 18.59. Significant variations were observed in moisture content (ranging from 53.20 g/100 g to 87.20 g/100 g), calorie content (ranging from 42.55 Kcal/100 g to 87.30 Kcal/100 g), adhesion (ranging from 0.92 to 1.84 mJ) and hardness (ranging from 2.97 to 4.19 N) (p < 0.05). Additionally, the free amino acid content varied from 22.47 mg/g to 65.42 mg/g. GC–MS analysis identified a total of 47 volatile flavor substances in varieties of loquats, including 13 aldehydes, 9 esters, 6 ketones, 2 acids, 3 alcohols, 2 phenols, 3 pyrazines, 1 furan and 8 other substances. The relative content of aldehydes was significantly higher than that of other chemicals. The VFP and FP samples exhibited higher aldehyde content compared to the NP and VP samples. Moreover, Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) revealed 18 marked compounds that could differentiate between 5 loquat species. Analysis using E-nose and E-tongue indicated significant changes in the olfactory and gustatory senses of loquats following preservation. The VFP samples demonstrated the most effective preservation of loquat quality with minimal impact. This study provides some theoretical guidance for the home preservation of loquats. Full article
17 pages, 2943 KiB  
Article
Synthesis, Crystal Structure, and Optical and Magnetic Properties of the New Quaternary Erbium Telluride EuErCuTe3: Experiment and Calculation
by Anna V. Ruseikina, Maxim V. Grigoriev, Ralf J. C. Locke, Vladimir A. Chernyshev, Alexander A. Garmonov and Thomas Schleid
Materials 2024, 17(10), 2284; https://doi.org/10.3390/ma17102284 (registering DOI) - 11 May 2024
Abstract
This paper reports for the first time on a new layered magnetic heterometallic erbium telluride EuErCuTe3. Single crystals of the compound were obtained from the elements at 1120 K using CsI as a flux. The crystal structure of EuErCuTe3 was [...] Read more.
This paper reports for the first time on a new layered magnetic heterometallic erbium telluride EuErCuTe3. Single crystals of the compound were obtained from the elements at 1120 K using CsI as a flux. The crystal structure of EuErCuTe3 was solved in the space group Cmcm (a = 4.3086(3) Å, b = 14.3093(9) Å, and c = 11.1957(7) Å) with the KZrCuS3 structure type. In the orthorhombic structure of erbium telluride, distorted octahedra ([ErTe6]9−) form two-dimensional layers (Er(Te1)2/2e(Te2)4/2k2), while distorted tetrahedra ([CuTe4]7−) form one-dimensionally connected substructures (Cu(Te1)2/2e(Te2)2/1t51) along the [100] direction. The distorted octahedra and tetrahedra form parallel two-dimensional layers (CuErTe322) between which Eu2+ ions are located in a trigonal-prismatic coordination environment (EuTe610). The trigonal prisms are connected by faces, forming chains (Eu(Te1)2/2(Te2)4/221) along the [100] direction. Regularities in the variations in structural parameters were established in the series of erbium chalcogenides (EuErCuCh3 (Ch = S, Se, and Te)) and tellurides (EuLnCuTe3 (Ln = Gd, Er, and Lu)). Ab-initio calculations of the crystal structure, phonon spectrum, and elastic properties of the compound EuErCuTe3 were performed. The types and wavenumbers of fundamental modes were determined, and the involvement of ions in the IR and Raman modes was assessed. The experimental Raman spectra were interpreted. The telluride EuErCuTe3 at temperatures below 4.2 K was ferrimagnetic, as were the sulfide and selenide derivatives (EuErCuCh3 (Ch = S and Se)). Its experimental magnetic characteristics were close to the calculated ones. The decrease in the magnetic phase transition temperature in the series of the erbium chalcogenides was discovered. Full article
(This article belongs to the Special Issue Obtaining and Characterization of New Materials, Volume IV)
16 pages, 12295 KiB  
Article
Ghost Fringe Suppression by Modifying the f-Number of the Diverger Lens for the Interferometric Measurement of Catadioptric Telescopes
by Yi-Kai Huang and Cheng-Huan Chen
Photonics 2024, 11(5), 453; https://doi.org/10.3390/photonics11050453 (registering DOI) - 11 May 2024
Abstract
A high-precision catadioptric telescope such as a space-borne telescope is usually tested with interferometer to check the optical quality in assembly. The coarse and fine alignment of the telescope are mainly based on the information from the coordinate measuring machine and the fringe [...] Read more.
A high-precision catadioptric telescope such as a space-borne telescope is usually tested with interferometer to check the optical quality in assembly. The coarse and fine alignment of the telescope are mainly based on the information from the coordinate measuring machine and the fringe pattern of the interferometer, respectively. In addition, further fine-tuning can be achieved according to the variation in wavefront error and Zernike data. The issue is that the vast majority of the catadioptric telescopes contain plural lens surfaces which could produce unwanted ghost fringes, disturbing the wavefront measurement. Technically, off-axis installation to shift away ghost fringes from central interferogram could be acceptable in some cases. Nevertheless, in this paper, the source of ghost fringe in interferometric measurement for catadioptric telescopes is investigated with light path simulation, and a solution of reducing the f-number of the diverger lens is proposed to eliminate the ghost fringe disturbance. Both simulation and experimental results verify the effectiveness of the proposed concept. Full article
(This article belongs to the Special Issue Optical Systems for Astronomy)
13 pages, 1952 KiB  
Article
Electrical Sensor Calibration by Fuzzy Clustering with Mandatory Constraint
by Shihong Yue, Keyi Fu, Liping Liu and Yuwei Zhao
Sensors 2024, 24(10), 3068; https://doi.org/10.3390/s24103068 (registering DOI) - 11 May 2024
Abstract
Electrical tomography sensors have been widely used for pipeline parameter detection and estimation. Before they can be used in formal applications, the sensors must be calibrated using enough labeled data. However, due to the high complexity of actual measuring environments, the calibrated sensors [...] Read more.
Electrical tomography sensors have been widely used for pipeline parameter detection and estimation. Before they can be used in formal applications, the sensors must be calibrated using enough labeled data. However, due to the high complexity of actual measuring environments, the calibrated sensors are inaccurate since the labeling data may be uncertain, inconsistent, incomplete, or even invalid. Alternatively, it is always possible to obtain partial data with accurate labels, which can form mandatory constraints to correct errors in other labeling data. In this paper, a semi-supervised fuzzy clustering algorithm is proposed, and the fuzzy membership degree in the algorithm leads to a set of mandatory constraints to correct these inaccurate labels. Experiments in a dredger validate the proposed algorithm in terms of its accuracy and stability. This new fuzzy clustering algorithm can generally decrease the error of labeling data in any sensor calibration process. Full article
(This article belongs to the Section Electronic Sensors)
16 pages, 982 KiB  
Article
Optimisation of Synchronous Grouting Mix Ratio for Shield Tunnels
by Hongmei Zhou, Yixiang Zhang, Wanxu Zhu, Qingyu Zhong and Xinyu Huang
Appl. Sci. 2024, 14(10), 4098; https://doi.org/10.3390/app14104098 (registering DOI) - 11 May 2024
Abstract
During shield construction in underground spaces, synchronous grouting slurry is poured between the surrounding rock and tunnel lining to ensure stability. For synchronous grouting slurries, few studies have investigated the relationship between the rheological parameters and physical properties, grout-segregation mechanism, and anti-segregation performance. [...] Read more.
During shield construction in underground spaces, synchronous grouting slurry is poured between the surrounding rock and tunnel lining to ensure stability. For synchronous grouting slurries, few studies have investigated the relationship between the rheological parameters and physical properties, grout-segregation mechanism, and anti-segregation performance. Therefore, we explored the relationships between the slurry rheological parameters, segregation rate, and bleeding rate. Cement, sand, fly ash, and bentonite were used to prepare the slurry, and the effects of different polycarboxylate water-reducing agents and dispersible latex powder dosages were studied. The rheological parameters of 16 groups of uniformly designed slurries were tested, and the data were fit using the Herschel–Bulkley model. The optimal mix ratio lowered the slurry segregation rate, and its rheological behaviour was consistent with the Herschel–Bulkley fluid characteristics. High-yield-shear-stress synchronous grouting slurries with high and low viscosity coefficients were less likely to bleed and segregate, respectively. The optimised slurry fluidity, 3 h bleeding rate, 24 h bleeding rate, segregation rate, coagulation time, and 28 days compressive strength were 257.5 mm, 0.71%, 0.36%, 3.1%, 6.7 h, and 2.61 MPa, respectively, which meet the requirements of a synchronous grouting slurry of shield tunnels for sufficiently preventing soil disturbance and deformation in areas surrounding underground construction sites. Full article
19 pages, 715 KiB  
Review
Assessing the Seasonal Water Requirement of Fully Mature Japanese Plum Orchards: A Systematic Review
by Munashe Mashabatu, Nonofo Motsei, Nebojša Jovanović, Timothy Dube, Ubaidullah Mathews and Yolanda Nqumkana
Appl. Sci. 2024, 14(10), 4097; https://doi.org/10.3390/app14104097 (registering DOI) - 11 May 2024
Abstract
Japanese plums have relatively high water requirements, which depend on supplementing rainfall volumes with accurately quantified irrigation water. There is a lack of knowledge on the seasonal water requirements of plum orchards. This gap in the literature poses an imminent threat to the [...] Read more.
Japanese plums have relatively high water requirements, which depend on supplementing rainfall volumes with accurately quantified irrigation water. There is a lack of knowledge on the seasonal water requirements of plum orchards. This gap in the literature poses an imminent threat to the long-term sustainability of the South African plum industry, which is particularly plagued by climate change and diminishing water resources. The systematic literature review conducted in this study aimed to provide a foundation for supporting water management in irrigated Japanese plum [Prunus salicina Lindl.] orchards. Seventeen peer-reviewed articles obtained from the literature were analyzed. Approximately 66% of the cultivars were cultivated under different regulated deficit irrigation regimes for water-saving purposes and to increase fruit quality. This review of our knowledge provided benchmark figures on the annual water requirements of Japanese plums. The full-year plum crop water requirements obtained from the literature ranged between 921 and 1211 mm a−1. Canopy growth, pruning and growing season length were the most common causes of differences in the water requirement estimates. Further research is required to measure the water requirement of plums from planting to full-bearing age and the response of plum trees to water stress, especially in the South African context. Full article
(This article belongs to the Section Agricultural Science and Technology)
15 pages, 1090 KiB  
Article
Discovery of the Larvae and Pupae of the Black Fly Simulium (Gomphostilbia) khelangense and Breeding Habitats of Potential Pest Species of the S. (G.) chumpornense Subgroup (Simuliidae)
by Isara Thanee, Waraporn Jumpato, Chavanut Jaroenchaiwattanachote, Bhuvadol Gomontean, Wannachai Wannasingha, San Namtaku, Peter H. Adler and Pairot Pramual
Insects 2024, 15(5), 346; https://doi.org/10.3390/insects15050346 (registering DOI) - 11 May 2024
Abstract
Two species of black flies (Simuliidae) in Thailand, Simulium chumpornense Takaoka and Kuvangkadilok, 2000, and S. khelangense Takaoka, Srisuka & Saeung, 2022, are potent vectors of avian blood protozoa of the genera Leucocytozoon and Trypanosoma and are pests of domestic avian species. Although [...] Read more.
Two species of black flies (Simuliidae) in Thailand, Simulium chumpornense Takaoka and Kuvangkadilok, 2000, and S. khelangense Takaoka, Srisuka & Saeung, 2022, are potent vectors of avian blood protozoa of the genera Leucocytozoon and Trypanosoma and are pests of domestic avian species. Although the adults are abundant throughout Thailand, information on their breeding habitats is limited, and the immature stages of S. khelangense are unknown. We collected the larvae and pupae of S. khelangense from the Mekong River, the first-ever record of Simuliidae from this large continental river. Mitochondrial cytochrome c oxidase I and internal transcribed spacer 2 were used to associate the larvae and pupae with known adults. Both genetic markers strongly supported their identity as S. khelangense. The larvae and pupa of S. khelangense are described. The pupal gill filaments, larval abdominal protuberances, and setae distinguish this species from other members of the S. varicorne species group. The immature stages of S. chumpornense inhabit a wide variety of flowing waters, from small streams (3 m wide) to enormous continental rivers (400 m wide); thus, S. chumpornense is a habitat generalist. In contrast, S. khelangense was found only in the large Mekong River and is, therefore, a habitat specialist. Both species can exploit their principal habitats and produce abundant adult populations. Full article
(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)
17 pages, 4838 KiB  
Article
A Novel, Soft, Cable-Driven Parallel Robot for Minimally Invasive Surgeries Based on Folded Pouch Actuators
by Jianlin Yang, Xinxin Li, Mark Runciman, James Avery, Zhangxi Zhou, Zhijun Sun and George Mylonas
Appl. Sci. 2024, 14(10), 4095; https://doi.org/10.3390/app14104095 (registering DOI) - 11 May 2024
Abstract
This paper introduces a soft, cable-driven parallel robot for minimally invasive surgeries. The robot comprises a pneumatic inflatable scaffold, six hydraulic, folded pouch actuators, and a hollow, cylindrical end-effector offering five degrees of freedom. A key development is the design of the pouch [...] Read more.
This paper introduces a soft, cable-driven parallel robot for minimally invasive surgeries. The robot comprises a pneumatic inflatable scaffold, six hydraulic, folded pouch actuators, and a hollow, cylindrical end-effector offering five degrees of freedom. A key development is the design of the pouch actuators, which are small, low-profile, simple structures, capable of a high stroke of 180° angular displacement. The scaffold, actuators, and plastic cables are economically and rapidly fabricated using laser cutting and welding techniques. Constructed primarily from soft plastic materials, the robot can be compactly folded into a cylinder measuring 110 mm in length and 14 mm in diameter. Upon inflation, the scaffold transforms into a hexagonal prism structure with side lengths of 34 mm and edge lengths of 100 mm. The kinematic model of the robot has been developed for workspace calculation and control purposes. A series of tests have been conducted to evaluate the performance of the actuator and the robot. Repeatability tests demonstrate the robot’s high repeatability, with mean and root mean square errors of 0.3645 mm and 0.4186 mm, respectively. The direct connection between the end-effector and the actuators theoretically eliminates cable friction, resulting in a hysteresis angle of less than 2°, as confirmed by the tracking results. In addition, simulated surgical tasks have been performed to further demonstrate the robot’s performance. Full article
(This article belongs to the Special Issue Advances in Intelligent Minimally Invasive Surgical Robots)
11 pages, 2336 KiB  
Case Report
Caudal Regression Syndrome First Diagnosed in Adulthood: A Case Report and a Review of the Literature
by Intars Bulahs, Agnete Teivāne, Ardis Platkājis and Arturs Balodis
Diagnostics 2024, 14(10), 1000; https://doi.org/10.3390/diagnostics14101000 (registering DOI) - 11 May 2024
Abstract
Caudal regression syndrome (CRS) is a rare congenital malformation characterized by incomplete development of the lower spine and spinal cord. Its estimated incidence ranges from 1 to 2 per 100,000 live births, leading to a spectrum of clinical presentations. Although most cases are [...] Read more.
Caudal regression syndrome (CRS) is a rare congenital malformation characterized by incomplete development of the lower spine and spinal cord. Its estimated incidence ranges from 1 to 2 per 100,000 live births, leading to a spectrum of clinical presentations. Although most cases are diagnosed during childhood, only a small number of cases have been documented in adults in the medical literature. Case Report: A 27-year-old woman underwent an outpatient magnetic resonance imaging (MRI) of the thoracolumbar spine due to severe lower back pain experienced for the first time. Despite congenital leg abnormalities and multiple childhood surgeries, no further investigations were conducted at that time. MRI revealed congenital anomalies consistent with CRS, including coccygeal agenesis, L5 sacralization, and spinal cord defects. The patient also had a long-standing pilonidal cyst treated conservatively, now requiring operative treatment due to an abscess. Conclusions: This report underscores a rare case of CRS initially misdiagnosed and mistreated over many years. It emphasizes the importance of considering less common diagnoses, especially when initial investigations yield inconclusive results. This clinical case demonstrates a highly valuable and educative radiological finding. In the literature, such cases with radiological findings in adults are still lacking. Full article
(This article belongs to the Special Issue Diagnosis and Management of Spinal Cord Injury)
24 pages, 17210 KiB  
Article
Research on the Population Flow and Mixing Characteristics of Pelleted Vegetable Seeds Based on the Bonded-Particle Model
by Jian Xu, Shunli Sun, Xiaoting Li, Zhiheng Zeng, Chongyang Han, Ting Tang and Weibin Wu
Agriculture 2024, 14(5), 752; https://doi.org/10.3390/agriculture14050752 (registering DOI) - 11 May 2024
Abstract
In order to precisely reproduce the precise seeding process of the population in the air-suction seed-metering device, it is necessary to execute accurate modeling of seed particles using the bonded-particle model, in combination with the discrete element method (DEM) and computational fluid dynamics [...] Read more.
In order to precisely reproduce the precise seeding process of the population in the air-suction seed-metering device, it is necessary to execute accurate modeling of seed particles using the bonded-particle model, in combination with the discrete element method (DEM) and computational fluid dynamics (CFD). Through the repose angle, slope screening, rotating container, and particle sedimentation experiments, in this paper, the influence of the filling accuracy of the bonded-particle model on the flow behavior and mixing characteristics of the seed population was first explored based on EDEM software. The viability of the suggested modeling approach for pelleted vegetable seeds, as described in this study, was confirmed by comparing experimental and simulation outcomes. The surface roughness values obtained from the studies above were utilized to assess the accuracy of the bonded-particle model in filling. Additionally, a mathematical technique for determining the surface roughness was provided. Furthermore, an analysis of the multiple contacts in the bonded-particle model was also performed. The results indicated that the simulation results closely matched the experimental data when the number of sub-spheres in the bonded-particle model was equal to or more than 70, as measured by the standard deviation. In addition, the most optimal modeling scheme for the pelletized vegetable seed bonded-particles, based on the cost of coupling simulation, was found to be the bonded-particle surface roughness (BS) with a value of 0.1. Ultimately, a practical example was utilized to demonstrate the utilization of the pelleted vegetable seed bonded-particle model and the DEM-CFD coupling approach in analyzing the accuracy of the seeding process in the air-suction seed-metering device. This example will serve as a valuable reference point for future field studies. Full article
(This article belongs to the Section Agricultural Technology)
17 pages, 12272 KiB  
Article
Strawberry Detection and Ripeness Classification Using YOLOv8+ Model and Image Processing Method
by Chenglin Wang, Haoming Wang, Qiyu Han, Zhaoguo Zhang, Dandan Kong and Xiangjun Zou
Agriculture 2024, 14(5), 751; https://doi.org/10.3390/agriculture14050751 (registering DOI) - 11 May 2024
Abstract
As strawberries are a widely grown cash crop, the development of strawberry fruit-picking robots for an intelligent harvesting system should match the rapid development of strawberry cultivation technology. Ripeness identification is a key step to realizing selective harvesting by strawberry fruit-picking robots. Therefore, [...] Read more.
As strawberries are a widely grown cash crop, the development of strawberry fruit-picking robots for an intelligent harvesting system should match the rapid development of strawberry cultivation technology. Ripeness identification is a key step to realizing selective harvesting by strawberry fruit-picking robots. Therefore, this study proposes combining deep learning and image processing for target detection and classification of ripe strawberries. First, the YOLOv8+ model is proposed for identifying ripe and unripe strawberries and extracting ripe strawberry targets in images. The ECA attention mechanism is added to the backbone network of YOLOv8+ to improve the performance of the model, and Focal-EIOU loss is used in loss function to solve the problem of imbalance between easy- and difficult-to-classify samples. Second, the centerline of the ripe strawberries is extracted, and the red pixels in the centerline of the ripe strawberries are counted according to the H-channel of their hue, saturation, and value (HSV). The percentage of red pixels in the centerline is calculated as a new parameter to quantify ripeness, and the ripe strawberries are classified as either fully ripe strawberries or not fully ripe strawberries. The results show that the improved YOLOv8+ model can accurately and comprehensively identify whether the strawberries are ripe or not, and the mAP50 curve steadily increases and converges to a relatively high value, with an accuracy of 97.81%, a recall of 96.36%, and an F1 score of 97.07. The accuracy of the image processing method for classifying ripe strawberries was 91.91%, FPR was 5.03%, and FNR was 14.28%. This study demonstrates the program’s ability to quickly and accurately identify strawberries at different stages of ripeness in a facility environment, which can provide guidance for selective picking by subsequent fruit-picking robots. Full article
(This article belongs to the Section Digital Agriculture)
16 pages, 1299 KiB  
Article
Convolutional Neural Network to Classify Infrared Thermal Images of Fractured Wrists in Pediatrics
by Olamilekan Shobayo, Reza Saatchi and Shammi Ramlakhan
Healthcare 2024, 12(10), 994; https://doi.org/10.3390/healthcare12100994 (registering DOI) - 11 May 2024
Abstract
Convolutional neural network (CNN) models were devised and evaluated to classify infrared thermal (IRT) images of pediatric wrist fractures. The images were recorded from 19 participants with a wrist fracture and 21 without a fracture (sprain). The injury diagnosis was by X-ray radiography. [...] Read more.
Convolutional neural network (CNN) models were devised and evaluated to classify infrared thermal (IRT) images of pediatric wrist fractures. The images were recorded from 19 participants with a wrist fracture and 21 without a fracture (sprain). The injury diagnosis was by X-ray radiography. For each participant, 299 IRT images of their wrists were recorded. These generated 11,960 images (40 participants × 299 images). For each image, the wrist region of interest (ROI) was selected and fast Fourier transformed (FFT) to obtain a magnitude frequency spectrum. The spectrum was resized to 100 × 100 pixels from its center as this region represented the main frequency components. Image augmentations of rotation, translation and shearing were applied to the 11,960 magnitude frequency spectra to assist with the CNN generalization during training. The CNN had 34 layers associated with convolution, batch normalization, rectified linear unit, maximum pooling and SoftMax and classification. The ratio of images for the training and test was 70:30, respectively. The effects of augmentation and dropout on CNN performance were explored. Wrist fracture identification sensitivity and accuracy of 88% and 76%, respectively, were achieved. The CNN model was able to identify wrist fractures; however, a larger sample size would improve accuracy. Full article
8 pages, 1286 KiB  
Communication
Adamantylated Calix[4]arenes Bearing CuAAC-Ready 2-Azidoethyl or Propargyl Functionalities
by Alexander Gorbunov, Maria Malakhova, Stanislav Bezzubov, Ivan Lentin, Vladimir Kovalev and Ivan Vatsouro
Molbank 2024, 2024(2), M1821; https://doi.org/10.3390/M1821 (registering DOI) - 11 May 2024
Abstract
1,3-Alternate calix[4]arenes were prepared, having bulky adamantyl groups in the p-positions of all four aromatic units of the macrocycles and pairs of propargyl or 2-azidoethyl groups alternating with n-propyl groups at the phenol oxygen atoms. The step-wise syntheses were carried out [...] Read more.
1,3-Alternate calix[4]arenes were prepared, having bulky adamantyl groups in the p-positions of all four aromatic units of the macrocycles and pairs of propargyl or 2-azidoethyl groups alternating with n-propyl groups at the phenol oxygen atoms. The step-wise syntheses were carried out through a selective distal alkylation of the parent p-adamantylcalix[4]arene with propargyl bromide or 1,2-dibromoethane, resulting in calix[4]arenes bearing pairs of propargyl or 2-bromoethyl groups at their narrow rims. The bromine atoms were replaced by azide groups, and then both calix[4]arene diethers were exhaustively alkylated at the remaining OH-groups with 1-iodopropane under stereoselective conditions to fix the macrocycles in an 1,3-alternate shape. The structures of the prepared p-adamantylcalix[4]arenes were confirmed by NMR and HRMS data, and, for the 1,3-alternate dipropargyl ether, the X-ray diffraction data were also collected. Preliminary data on the reactivity of the prepared calixarenes under the CuAAC conditions suggested a strong steric hampering created by the adamantane units nearby the reacting alkyne or azide groups that affected the outcome of the two-fold cycloaddition involving the calixarene bis(azides) or bis(alkynes) as complementary partners. Full article
(This article belongs to the Section Organic Synthesis)
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