Sign in to use this feature.

Years

Between: -

Search Results (62)

Search Parameters:
Keywords = SBG

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
12 pages, 2248 KiB  
Article
Research on Conduction Delay Time Characteristics of Double-Gap Surface Flashover Triggered Multistage Vacuum Switch
by Ming Zhang, Minfu Liao, Liang Bu, Gang Lu, Longfei Yu, Yifan Sun and Xiongying Duan
Energies 2024, 17(18), 4656; https://doi.org/10.3390/en17184656 - 18 Sep 2024
Abstract
Due to the insulation saturation effect of a vacuum gap, the series connection is the main method to improve the capability of the triggered vacuum switch (STVS) to withstand voltage. In this paper, a double-gap surface flashover triggered multistage vacuum switch (DMVS) is [...] Read more.
Due to the insulation saturation effect of a vacuum gap, the series connection is the main method to improve the capability of the triggered vacuum switch (STVS) to withstand voltage. In this paper, a double-gap surface flashover triggered multistage vacuum switch (DMVS) is constructed based on a removable vacuum chamber. The DMVS consists of a surface flashover triggered vacuum gap (STG) and a self-breakdown vacuum gap (SBG) in series. The trend in DMVS conduction delay time under different operating parameters and gap distances is firstly measured through experiments, and then the conduction delay time characteristics of DMVS and single-gap STVS compared. The test results show that increasing the trigger current and operating voltage and decreasing the gap distance of each vacuum gap can optimize the conduction delay time of the DMVS, but the voltage division ratio between the STG and the SBG has no obvious influence on the conduction delay time. The comparison result between the DMVS and the STVS shows that increasing the number of series gaps increases the conduction delay time but, for a certain vacuum gap distance, DMVS exhibits superior conduction delay time characteristics compared to STVS. Full article
(This article belongs to the Section F: Electrical Engineering)
Show Figures

Figure 1

16 pages, 995 KiB  
Article
Extended Release of Bupivacaine from Temperature-Responsive PNDJ Hydrogels Improves Postoperative Weight-Bearing in Rabbits Following Knee Surgery
by Derek J. Overstreet, Gabriel Zdrale and Alex C. McLaren
Pharmaceuticals 2024, 17(7), 879; https://doi.org/10.3390/ph17070879 - 3 Jul 2024
Cited by 1 | Viewed by 545
Abstract
Effective treatment of postoperative pain lasting for multiple days without opioids is an important clinical need. We previously reported analgesia lasting up to 96 h in a porcine soft tissue model of postoperative pain using SBG004, an extended-release formulation of bupivacaine based on [...] Read more.
Effective treatment of postoperative pain lasting for multiple days without opioids is an important clinical need. We previously reported analgesia lasting up to 96 h in a porcine soft tissue model of postoperative pain using SBG004, an extended-release formulation of bupivacaine based on the temperature-responsive polymer poly(N-isopropylacrylamide-co-dimethylbutyrolactone acrylamide-co-Jeffamine M-1000 acrylamide) [PNDJ]. Orthopaedic surgical sites such as the knee can involve complex sensory innervation which presents a distinct challenge to local anesthetic delivery. The purpose of this work was to evaluate the pharmacokinetics and efficacy of SBG004 in an orthopaedic surgical model in comparison to currently available local anesthetics. Pharmacokinetics following periarticular (PA) or intraarticular (IA) injection of SBG004 were compared against liposomal bupivacaine (Lip-Bupi) PA in New Zealand White rabbits (all doses 14.5 mg/kg). Analgesic efficacy of SBG004 (IA, PA, or IA + PA), three active comparators, and saline was evaluated following knee surgery in New Zealand White rabbits. Analgesia was assessed via weight-bearing on the operated limb during spontaneous large steps in video recordings. Systemic bupivacaine exposure lasted at least 7 days for SBG004 PA, 4 days for SBG004 IA, and 2 days for Lip-Bupi PA. In the analgesia study, weight-bearing in all active groups except SBG004 IA was more frequent versus saline through 8 h postoperatively (p < 0.05). Only SBG004 IA + PA resulted in a higher proportion of weight-bearing rabbits at 24 h versus saline (6/7 versus 2/10, p = 0.015). Analysis of pooled data from 24–72 h showed significantly greater frequency of weight-bearing in rabbits receiving SBG004 IA + PA (71%) versus saline (37%), ropivacaine cocktail (41%), and Lip-Bupi PA (36%). The results indicate that the release profile from SBG004 PA or IA coincides reasonably with the time course of postoperative pain, and SBG004 may produce longer duration of analgesia than local anesthetics currently used in knee surgery, including during the period of 24–72 h recognized as a target for extended-release local anesthetics. Full article
(This article belongs to the Special Issue Drug Delivery Systems for Local Anesthetics)
Show Figures

Figure 1

19 pages, 3227 KiB  
Article
Hyperspectral Leaf Area Index and Chlorophyll Retrieval over Forest and Row-Structured Vineyard Canopies
by Luke A. Brown, Harry Morris, Andrew MacLachlan, Francesco D’Adamo, Jennifer Adams, Ernesto Lopez-Baeza, Erika Albero, Beatriz Martínez, Sergio Sánchez-Ruiz, Manuel Campos-Taberner, Antonio Lidón, Cristina Lull, Inmaculada Bautista, Daniel Clewley, Gary Llewellyn, Qiaoyun Xie, Fernando Camacho, Julio Pastor-Guzman, Rosalinda Morrone, Morven Sinclair, Owen Williams, Merryn Hunt, Andreas Hueni, Valentina Boccia, Steffen Dransfeld and Jadunandan Dashadd Show full author list remove Hide full author list
Remote Sens. 2024, 16(12), 2066; https://doi.org/10.3390/rs16122066 - 7 Jun 2024
Viewed by 1436
Abstract
As an unprecedented stream of decametric hyperspectral observations becomes available from recent and upcoming spaceborne missions, effective algorithms are required to retrieve vegetation biophysical and biochemical variables such as leaf area index (LAI) and canopy chlorophyll content (CCC). In the context of missions [...] Read more.
As an unprecedented stream of decametric hyperspectral observations becomes available from recent and upcoming spaceborne missions, effective algorithms are required to retrieve vegetation biophysical and biochemical variables such as leaf area index (LAI) and canopy chlorophyll content (CCC). In the context of missions such as the Environmental Mapping and Analysis Program (EnMAP), Precursore Iperspettrale della Missione Applicativa (PRISMA), Copernicus Hyperspectral Imaging Mission for the Environment (CHIME), and Surface Biology Geology (SBG), several retrieval algorithms have been developed based upon the turbid medium Scattering by Arbitrarily Inclined Leaves (SAIL) radiative transfer model. Whilst well suited to cereal crops, SAIL is known to perform comparatively poorly over more heterogeneous canopies (including forests and row-structured crops). In this paper, we investigate the application of hybrid radiative transfer models, including a modified version of SAIL (rowSAIL) and the Invertible Forest Reflectance Model (INFORM), to such canopies. Unlike SAIL, which assumes a horizontally homogeneous canopy, such models partition the canopy into geometric objects, which are themselves treated as turbid media. By enabling crown transmittance, foliage clumping, and shadowing to be represented, they provide a more realistic representation of heterogeneous vegetation. Using airborne hyperspectral data to simulate EnMAP observations over vineyard and deciduous broadleaf forest sites, we demonstrate that SAIL-based algorithms provide moderate retrieval accuracy for LAI (RMSD = 0.92–2.15, NRMSD = 40–67%, bias = −0.64–0.96) and CCC (RMSD = 0.27–1.27 g m−2, NRMSD = 64–84%, bias = −0.17–0.89 g m−2). The use of hybrid radiative transfer models (rowSAIL and INFORM) reduces bias in LAI (RMSD = 0.88–1.64, NRMSD = 27–64%, bias = −0.78–−0.13) and CCC (RMSD = 0.30–0.87 g m−2, NRMSD = 52–73%, bias = 0.03–0.42 g m−2) retrievals. Based on our results, at the canopy level, we recommend that hybrid radiative transfer models such as rowSAIL and INFORM are further adopted for hyperspectral biophysical and biochemical variable retrieval over heterogeneous vegetation. Full article
(This article belongs to the Section Environmental Remote Sensing)
Show Figures

Graphical abstract

27 pages, 5434 KiB  
Article
Characterization and Validation of ECOSTRESS Sea Surface Temperature Measurements at 70 m Spatial Scale
by David S. Wethey, Nicolas Weidberg, Sarah A. Woodin and Jorge Vazquez-Cuervo
Remote Sens. 2024, 16(11), 1876; https://doi.org/10.3390/rs16111876 - 24 May 2024
Viewed by 636
Abstract
The ECOSTRESS push-whisk thermal radiometer on the International Space Station provides the highest spatial resolution temperature retrievals over the ocean that are currently available. It is a precursor to the future TRISHNA (CNES/ISRO), SBG (NASA), and LSTM (ESA) 50 to 70 m scale [...] Read more.
The ECOSTRESS push-whisk thermal radiometer on the International Space Station provides the highest spatial resolution temperature retrievals over the ocean that are currently available. It is a precursor to the future TRISHNA (CNES/ISRO), SBG (NASA), and LSTM (ESA) 50 to 70 m scale missions. Radiance transfer simulations and triple collocations with in situ ocean observations and NOAA L2P geostationary satellite ocean temperature retrievals were used to characterize brightness temperature biases and their sources in ECOSTRESS Collection 1 (software Build 6) data for the period 12 January 2019 to 31 October 2022. Radiometric noise, non-uniformities in the focal plane array, and black body temperature dynamics were characterized in ocean scenes using L1A raw instrument data, L1B calibrated radiances, and L2 skin temperatures. The mean brightness temperature biases were −1.74, −1.45, and −1.77 K relative to radiance transfer simulations in the 8.78, 10.49, and 12.09 µm wavelength bands, respectively, and skin temperatures had a −1.07 K bias relative to in situ observations. Cross-track noise levels range from 60 to 600 mK and vary systematically along the focal plane array and as a function of wavelength band and scene temperature. Overall, radiometric uncertainty is most strongly influenced by cross-track noise levels and focal plane non-uniformity. Production of an ECOSTRESS sea surface temperature product that meets the requirements of the SST community will require calibration methods that reduce the biases, noise levels, and focal plane non-uniformities. Full article
Show Figures

Figure 1

26 pages, 1172 KiB  
Article
Impact of Industry 5.0 Readiness on Sustainable Business Growth of Marine Food Processing SMEs in Thailand
by Meena Madhavan, Mohammed Ali Sharafuddin and Sutee Wangtueai
Adm. Sci. 2024, 14(6), 110; https://doi.org/10.3390/admsci14060110 - 22 May 2024
Viewed by 1259
Abstract
This research aims to develop a conceptual framework and propositions to establish and test the causal relationships between Industry 5.0 readiness (I5.0R), global value chain (GVC) participation, business competitiveness (BC), and sustainable business growth (SBG) of small and medium-sized enterprises (SMEs). This study [...] Read more.
This research aims to develop a conceptual framework and propositions to establish and test the causal relationships between Industry 5.0 readiness (I5.0R), global value chain (GVC) participation, business competitiveness (BC), and sustainable business growth (SBG) of small and medium-sized enterprises (SMEs). This study focuses on Industry 5.0 readiness, evaluated through human-centricity, fairtrade practices, lean management, sustainability practices, and business competitiveness, measured by marketing, resources, production, and finance. Both constructs were developed and tested as higher-order constructs, while GVC participation and sustainable business growth were assessed as lower-order constructs. Data were collected from marine food processing SMEs in Thailand using a purposive sampling technique. This study tested and confirmed the content validity, construct validity, and reliability of both lower and higher-order models. Using partial least squares structural equation modeling (PLS-SEM) with bootstrapping (n = 1000), the results indicated significant positive impacts of Industry 5.0 readiness on GVC participation, Industry 5.0 readiness on business competitiveness, GVC participation on business competitiveness, and business competitiveness on the sustainable business growth of SMEs. Additionally, business competitiveness was found to mediate the relationship between Industry 5.0 readiness and sustainable business growth. These findings contribute to the literature on Industry 5.0, GVCs, and SME business competitiveness, offering practical insights for SMEs and policymakers aiming to enhance sustainable growth through strategic readiness and competitiveness in Industry 5.0 practices. The implications and directions for further research in Industry 5.0 readiness of SMEs are presented. Full article
(This article belongs to the Section Strategic Management)
Show Figures

Figure 1

20 pages, 29321 KiB  
Article
Mesh Characteristic Analysis of Spiral Bevel Gear Pairs Considering Assembly Errors and Tooth Tip Chipping Faults
by Ying Wang, Juntao Zhang, Zhanwei Li, Ruijun Liang, Rupeng Zhu and Hui Ma
Appl. Sci. 2024, 14(8), 3227; https://doi.org/10.3390/app14083227 - 11 Apr 2024
Viewed by 802
Abstract
Due to machining errors, location inaccuracies, human error, and various other factors, it is challenging to avoid assembly errors during the production of spiral bevel gears (SBGs). When SBG assembly errors occur, it can cause the appearance of edge contact and may even [...] Read more.
Due to machining errors, location inaccuracies, human error, and various other factors, it is challenging to avoid assembly errors during the production of spiral bevel gears (SBGs). When SBG assembly errors occur, it can cause the appearance of edge contact and may even lead to severe tooth tip chipping. In this study, we propose an improved method based on loaded tooth contact analysis (LTCA) to examine mesh characteristics, including time-varying mesh stiffness (TVMS), unloaded transmission error, and contact stress. Furthermore, we explore the effects of assembly errors and tooth tip chipping. Moreover, it is observed that assembly errors can alter the contact area of SBGs and potentially reduce the peak-to-peak value of TVMS. Additionally, the occurrence of tooth tip chipping decreases TVMS within the chipping region, lowers transmission error, and increases maximum contact stress. Notably, when assembly errors are present, the reduction in TVMS due to tooth tip chipping exceeds that of a properly assembled SBG pair. Full article
(This article belongs to the Section Mechanical Engineering)
Show Figures

Figure 1

17 pages, 2881 KiB  
Article
Expanded Signal to Noise Ratio Estimates for Validating Next-Generation Satellite Sensors in Oceanic, Coastal, and Inland Waters
by Raphael M. Kudela, Stanford B. Hooker, Liane S. Guild, Henry F. Houskeeper and Niky Taylor
Remote Sens. 2024, 16(7), 1238; https://doi.org/10.3390/rs16071238 - 31 Mar 2024
Viewed by 1093
Abstract
The launch of the NASA Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) and the Surface Biology and Geology (SBG) satellite sensors will provide increased spectral resolution compared to existing platforms. These new sensors will require robust calibration and validation datasets, but existing field-based instrumentation [...] Read more.
The launch of the NASA Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) and the Surface Biology and Geology (SBG) satellite sensors will provide increased spectral resolution compared to existing platforms. These new sensors will require robust calibration and validation datasets, but existing field-based instrumentation is limited in its availability and potential for geographic coverage, particularly for coastal and inland waters, where optical complexity is substantially greater than in the open ocean. The minimum signal-to-noise ratio (SNR) is an important metric for assessing the reliability of derived biogeochemical products and their subsequent use as proxies, such as for biomass, in aquatic systems. The SNR can provide insight into whether legacy sensors can be used for algorithm development as well as calibration and validation activities for next-generation platforms. We extend our previous evaluation of SNR and associated uncertainties for representative coastal and inland targets to include the imaging sensors PRISM and AVIRIS-NG, the airborne-deployed C-AIR radiometers, and the shipboard HydroRad and HyperSAS radiometers, which were not included in the original analysis. Nearly all the assessed hyperspectral sensors fail to meet proposed criteria for SNR or uncertainty in remote sensing reflectance (Rrs) for some part of the spectrum, with the most common failures (>20% uncertainty) below 400 nm, but all the sensors were below the proposed 17.5% uncertainty for derived chlorophyll-a. Instrument suites for both in-water and airborne platforms that are capable of exceeding all the proposed thresholds for SNR and Rrs uncertainty are commercially available. Thus, there is a straightforward path to obtaining calibration and validation data for current and next-generation sensors, but the availability of suitable high spectral resolution sensors is limited. Full article
(This article belongs to the Section Ocean Remote Sensing)
Show Figures

Figure 1

10 pages, 1213 KiB  
Article
The Association of High-Molecular-Weight Hyaluronic Acid (HMWHA), Alpha Lipoic Acid (ALA), Magnesium, Vitamin B6, and Vitamin D Improves Subchorionic Hematoma Resorption in Women with Threatened Miscarriage: A Pilot Clinical Study
by Giuseppina Porcaro, Antonio Simone Laganà, Isabella Neri and Cesare Aragona
J. Clin. Med. 2024, 13(3), 706; https://doi.org/10.3390/jcm13030706 - 25 Jan 2024
Viewed by 3020
Abstract
Background—We evaluated whether the oral intake of high-molecular-weight hyaluronic acid (HMWHA) in association with alpha lipoic acid (ALA), magnesium, vitamin B6, and vitamin D can improve the resorption of subchorionic hematoma in cases of threatened miscarriage. Methods—In this study, we enrolled 56 pregnant [...] Read more.
Background—We evaluated whether the oral intake of high-molecular-weight hyaluronic acid (HMWHA) in association with alpha lipoic acid (ALA), magnesium, vitamin B6, and vitamin D can improve the resorption of subchorionic hematoma in cases of threatened miscarriage. Methods—In this study, we enrolled 56 pregnant women with threatened miscarriage (i.e., subchorionic hematomas, pelvic pain/uterine contractions, and/or vaginal bleeding) between the 6th and the 13th week of gestation. They were treated with vaginal progesterone (200 mg/twice a day) (control group; n = 25) or vaginal progesterone plus oral 200 mg HMWHA, 100 mg ALA, 450 mg magnesium, 2.6 mg vitamin B6, and 50 mcg vitamin D (treatment group; n = 31; DAV®-HA, LoLi Pharma srl, Rome, Italy). An ultrasound scan was performed at the first visit (T0) and after 7 days (T1) and 14 days (T2) until hematoma resorption. Results—At the ultrasound scan, the treatment group showed faster resorption of the subchorionic hematoma compared with the control group, both at T1 (control group 140 (112–180), treated group 84 (40–112), p < 0.0031), and T2 (control group: 72 (48–112), treated group: 0 (0–0), p < 0.0001). Moreover, subjective symptoms, such as vaginal bleeding, abdominal pain, and uterine contractions, showed a faster decrease in the treatment group than in the control group. Conclusions—The association may more rapidly improve the resolution of threatened miscarriage and related symptoms compared to the standard local protocol. Full article
(This article belongs to the Section Obstetrics & Gynecology)
Show Figures

Figure 1

18 pages, 1517 KiB  
Article
Modification of Physiochemical and Techno-Functional Properties of Stink Bean (Parkia speciosa) by Germination and Hydrothermal Cooking Treatment
by Seema Vijay Medhe, Aurawan Kringkasemsee Kettawan, Manoj Tukaram Kamble, Nuntawat Monboonpitak, Kim D. Thompson, Aikkarach Kettawan and Nopadon Pirarat
Foods 2023, 12(24), 4480; https://doi.org/10.3390/foods12244480 - 14 Dec 2023
Cited by 1 | Viewed by 1274
Abstract
Stink bean, Parkia speciosa, is recognized as a significantly underutilized legume with versatile utility and diverse benefits. However, information on the impact of different processing methods, such as germination and hydrothermal cooking, is scarce on stink beans (SBs). Therefore, the current research [...] Read more.
Stink bean, Parkia speciosa, is recognized as a significantly underutilized legume with versatile utility and diverse benefits. However, information on the impact of different processing methods, such as germination and hydrothermal cooking, is scarce on stink beans (SBs). Therefore, the current research aimed to explore the efficacy of germination (G) and hydrothermal cooking (HTC) on the physiochemical properties, proximate composition, techno-functional properties, and antioxidant potential of SB flour. Furthermore, Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM) were employed to assess structural and morphological changes. The results revealed that the physiochemical properties of SB were significantly enhanced through processing, with more pronounced improvements observed during germination. Additionally, SBG exhibited a significantly higher protein content and lower fat content compared to SBHTC and stink bean raw (SBR). Moreover, techno-functional properties such as color intensity, least gelation concentration, and pasting properties were significantly improved in SBG compared to SBHTC and SBR. FTIR analysis of SBG and SBHTC indicated structural modifications in the lipid, protein, and carbohydrate molecules. FESEM examination revealed morphological changes in SBG and SBHTC when compared to SBR. Importantly, SBG exhibited higher antioxidant activity and total phenolic content in comparison to SBHTC and SBR. Therefore, processed SB flour can be incorporated and utilized in product development, highlighting its potential as a plant-based protein source for protein-rich breakfast bars and cookies. Full article
(This article belongs to the Section Food Nutrition)
Show Figures

Figure 1

17 pages, 630 KiB  
Article
Conceptualising Marine Biodiversity Mainstreaming as an Enabler of Regional Sustainable Blue Growth: The Case of the European Atlantic Area
by Zacharoula Kyriazi, Leonor Ribeiro de Almeida, Agnès Marhadour, Christina Kelly, Wesley Flannery, Arantza Murillas-Maza, Régis Kalaydjian, Desiree Farrell, Liam M. Carr, Daniel Norton and Stephen Hynes
Sustainability 2023, 15(24), 16762; https://doi.org/10.3390/su152416762 - 12 Dec 2023
Viewed by 1357
Abstract
After recognizing the importance of marine and coastal resources and the use of marine space for economic growth, the European Union (EU) created and implemented a long-term Blue Economy (BE) strategy that supports the development of traditional and emerging marine and maritime sectors, [...] Read more.
After recognizing the importance of marine and coastal resources and the use of marine space for economic growth, the European Union (EU) created and implemented a long-term Blue Economy (BE) strategy that supports the development of traditional and emerging marine and maritime sectors, aiming at the enhancement of Blue Growth (BG). However, despite the existence of a robust policy framework that supports the expansion of BE sectors at both an EU Sea Basin and state level, scholars have been sceptical as to whether the pursuit of BG adequately addresses the challenges that usually come with economic development, including those of climate change and marine biodiversity loss. Various frameworks for integrating sectoral goals with each other and with environmental goals that could facilitate the transition towards Sustainable Blue Growth (SBG) already exist and have been suggested and promoted by the European Commission, such as Ecosystem-Based Management (EBM) and Marine Spatial Planning (MSP). They require the consideration of marine ecosystems and biodiversity and their protection as one of the BE sectors to be integrated via planning and management, which in turn requires the estimation of the value of ecosystem services and the spatial implications thereof. Nonetheless, there is little evidence or real-world examples on whether and how ecosystems, and within them coastal and marine biodiversity, are actually integrated (i.e., mainstreamed) when developing sectoral policies and planning and implementing economic activities at sea at various scales, i.e., local, national, and regional, and what the necessary steps and actions are that would facilitate such mainstreaming. By seeking evidence in EU and Atlantic Arc (AA) member states’ sectoral policies on marine tourism, ports and shipping, marine renewable energy, and fisheries and aquaculture (as promoted by the Atlantic Maritime Strategy and its corresponding action plans) and in the outcomes of the Interreg Atlantic Funded Research Project MOSES (aiming at valuating a Sustainable Blue Economy at the national and regional scale of the EU AA), the present article focused on understanding if and how marine biodiversity is taken into consideration by EU and AA BE and/or BG policies, strategies, and sectoral developments. Τhe selected sectoral policies demonstrate a good uptake of marine-ecosystem- and biodiversity-related challenges; however, at both the EU and the AA member-state level, it is unclear whether and how marine ecosystems and biodiversity are addressed as a separate BE sector. As such, we argue why and how Marine Biodiversity Mainstreaming (MBM) could address this gap, and hence it could contribute to planning, implementing, and managing maritime economic activities towards SBG at the Sea Basin level. This is demonstrated by illustrating the central role of MBM in enabling (and being further enabled by) the above integrative frameworks (i.e., MSP and EBM) and by presenting the key elements and actions required for such facilitation. Full article
(This article belongs to the Section Economic and Business Aspects of Sustainability)
Show Figures

Figure 1

15 pages, 3253 KiB  
Article
Remote Sensing of Snow Parameters: A Sensitivity Study of Retrieval Performance Based on Hyperspectral versus Multispectral Data
by Elliot Pachniak, Wei Li, Tomonori Tanikawa, Charles Gatebe and Knut Stamnes
Algorithms 2023, 16(10), 493; https://doi.org/10.3390/a16100493 - 23 Oct 2023
Cited by 1 | Viewed by 1559
Abstract
Snow parameters have traditionally been retrieved using discontinuous, multi-band sensors; however, continuous hyperspectral sensors are now being developed as an alternative. In this paper, we investigate the performance of various sensor configurations using machine learning neural networks trained on a simulated dataset. Our [...] Read more.
Snow parameters have traditionally been retrieved using discontinuous, multi-band sensors; however, continuous hyperspectral sensors are now being developed as an alternative. In this paper, we investigate the performance of various sensor configurations using machine learning neural networks trained on a simulated dataset. Our results show improvements in the accuracy of retrievals of snow grain size and impurity concentration for continuous hyperspectral channel configurations. Retrieval accuracy of snow albedo was found to be similar for all channel configurations. Full article
Show Figures

Figure 1

19 pages, 5180 KiB  
Article
Self-Supervised Convolutional Neural Network Learning in a Hybrid Approach Framework to Estimate Chlorophyll and Nitrogen Content of Maize from Hyperspectral Images
by Ignazio Gallo, Mirco Boschetti, Anwar Ur Rehman and Gabriele Candiani
Remote Sens. 2023, 15(19), 4765; https://doi.org/10.3390/rs15194765 - 28 Sep 2023
Cited by 5 | Viewed by 1293
Abstract
The new generation of available (i.e., PRISMA, ENMAP, DESIS) and future (i.e., ESA-CHIME, NASA-SBG) spaceborne hyperspectral missions provide unprecedented data for environmental and agricultural monitoring, such as crop trait assessment. This paper focuses on retrieving two crop traits, specifically Chlorophyll and Nitrogen content [...] Read more.
The new generation of available (i.e., PRISMA, ENMAP, DESIS) and future (i.e., ESA-CHIME, NASA-SBG) spaceborne hyperspectral missions provide unprecedented data for environmental and agricultural monitoring, such as crop trait assessment. This paper focuses on retrieving two crop traits, specifically Chlorophyll and Nitrogen content at the canopy level (CCC and CNC), starting from hyperspectral images acquired during the CHIME-RCS project, exploiting a self-supervised learning (SSL) technique. SSL is a machine learning paradigm that leverages unlabeled data to generate valuable representations for downstream tasks, bridging the gap between unsupervised and supervised learning. The proposed method comprises pre-training and fine-tuning procedures: in the first stage, a de-noising Convolutional Autoencoder is trained using pairs of noisy and clean CHIME-like images; the pre-trained Encoder network is utilized as-is or fine-tuned in the second stage. The paper demonstrates the applicability of this technique in hybrid approach methods that combine Radiative Transfer Modelling (RTM) and Machine Learning Regression Algorithm (MLRA) to set up a retrieval schema able to estimate crop traits from new generation space-born hyperspectral data. The results showcase excellent prediction accuracy for estimating CCC (R2 = 0.8318; RMSE = 0.2490) and CNC (R2 = 0.9186; RMSE = 0.7908) for maize crops from CHIME-like images without requiring further ground data calibration. Full article
Show Figures

Figure 1

21 pages, 12650 KiB  
Article
Utilizing Remote Sensing and Satellite-Based Bouguer Gravity data to Predict Potential Sites of Hydrothermal Minerals and Gold Deposits in Central Saudi Arabia
by Amr Abd El-Raouf, Fikret Doğru, Islam Azab, Lincheng Jiang, Kamal Abdelrahman, Mohammed S. Fnais and Omar Amer
Minerals 2023, 13(8), 1092; https://doi.org/10.3390/min13081092 - 15 Aug 2023
Cited by 1 | Viewed by 2154
Abstract
This article aims to aid in exploring and forecasting hydrothermal minerals and gold deposits in Central Saudi Arabia (SA), with a focus on structural contexts. Remote sensing (RS) and satellite-based Bouguer gravity (SBG) data were integrated in order to create a mineral prediction [...] Read more.
This article aims to aid in exploring and forecasting hydrothermal minerals and gold deposits in Central Saudi Arabia (SA), with a focus on structural contexts. Remote sensing (RS) and satellite-based Bouguer gravity (SBG) data were integrated in order to create a mineral prediction map for the researched location. Data from the Landsat Operational Land Imager (OLI) and Shuttle Radar Topography Mission (SRTM) were transformed and enhanced using a variety of approaches. The delineation of hydrothermal alteration zones (HAZs) and highlighting of structural discontinuities in the OLI data were made possible using band ratios and oriented principal component analysis (PCA). Additionally, the underlying structural features were successfully exposed by processing the SBG using a variety of edge detection techniques, like the analytical signal (AS), total horizontal derivative (THD), tilt angle (TA), horizontal tilt angle (TDX), theta map (TM), horizontal derivative of the tilt derivative (HD_TDR), horizontal gradient of the tilt angle (HGTA), tilt angle of the analytical signal (TAAS), and soft sign function (SF). As a result, more prominent lineaments were found in the NW–SE, NNW–SSE, NE–SW, and NNE–SSW directions than in the N–S and E–W directions. The GIS incorporated surface/subsurface geological structure density maps with zones of hydrothermal alteration. It was found that the lineaments derived from the analysis of the RS and SBG data were more in line with the HAZs, which demonstrated the common connection between alteration zones and deep lineaments. The findings revealed a mineral prediction map with extremely low to extremely high probabilities. Overall, combining RS and SBG data effectively identified probable mineralization sites associated with hydrothermal processes and made it easier to create this study’s final predictive mineralization map. Full article
Show Figures

Figure 1

14 pages, 4049 KiB  
Article
Valorization of Cellulose-Based Materials from Agricultural Waste: Comparison between Sugarcane Bagasse and Rice Straw
by Wiriya Thongsomboon, Yodthong Baimark and Prasong Srihanam
Polymers 2023, 15(15), 3190; https://doi.org/10.3390/polym15153190 - 27 Jul 2023
Cited by 6 | Viewed by 2350
Abstract
Sugarcane bagasse and rice straw are major agricultural byproducts often discarded or burned as waste after cultivation, leaving their untapped potential for utilization. In this work, cellulose fibers were extracted from sugarcane bagasse and rice straw using a simple procedure: alkaline treatment with [...] Read more.
Sugarcane bagasse and rice straw are major agricultural byproducts often discarded or burned as waste after cultivation, leaving their untapped potential for utilization. In this work, cellulose fibers were extracted from sugarcane bagasse and rice straw using a simple procedure: alkaline treatment with sodium hydroxide, bleaching with sodium hypochlorite, and acid hydrolysis. The obtained cellulosic materials were successfully prepared into milky white and transparent films, of which the transparency slightly decreased with the addition of glycerol. The surface of all the films appeared homogeneous with a random orientation of fibers. The rice-straw (RS) film had a more fragile texture than the sugarcane-bagasse (SBG) film. The FTIR analysis clearly indicated the functional groups of cellulose, as well as glycerol for the films mixed with glycerol. Thermal analysis showed that the native SBG film decomposed at 346 °C, higher than the native RS film (339 °C). The presence of glycerol in the films resulted in slightly lower maximum decomposition temperature (Td,max) values as well as mechanical properties. Regarding water susceptibility, the RS film had a higher percentage than the native SBG and glycerol-mixed SBG films. The extracted cellulose from both sources could form almost spherical-shaped cellulose particles. Thus, through the simple extraction method, sugarcane bagasse and rice straw could serve as excellent sources of cellulose materials for preparing cellulose films and particles, which would be advantageous to the development of cellulose-based materials. Full article
(This article belongs to the Special Issue Biopolymer-Based Films and Coatings for Packaging Applications)
Show Figures

Graphical abstract

15 pages, 7093 KiB  
Article
Research on Active Precontrol Strategy for Shape and Performance of Helicopter Spiral Bevel Gears
by Yanming Mu, Xiangying Hou and Xueming He
Appl. Sci. 2023, 13(14), 8527; https://doi.org/10.3390/app13148527 - 24 Jul 2023
Viewed by 957
Abstract
Gear vibration becomes unmanageable under extreme conditions, which shortens the time between overhauls of the helicopter reducer and affects the service efficiency of helicopters. For this purpose, an active precontrol strategy for shape and performance was developed for spiral bevel gear (SBG) systems, [...] Read more.
Gear vibration becomes unmanageable under extreme conditions, which shortens the time between overhauls of the helicopter reducer and affects the service efficiency of helicopters. For this purpose, an active precontrol strategy for shape and performance was developed for spiral bevel gear (SBG) systems, thus prolonging the reliable service period of helicopters. Firstly, the perfect pinion surface was built based on the preset contact path (CP) and transmission error (TE). Secondly, through a combination of tooth contact analysis (TCA) and loaded tooth contact analysis (LTCA), the loaded transmission error (LTE), meshing stiffness (MS), and meshing impact (MI) of the SBG transmission were obtained. Thirdly, an eight-degrees-of-freedom (8-DOF) dynamic model was built, and a simplified dynamic model was generated based on this. As regards the dynamic response, the root mean square of normal vibration acceleration (RMA) of the SBG transmission was obtained by solving the differential equation of motion. The RMA of the SBG transmission was also analysed based on the basic theory of vector structural mechanics. Finally, an optimization model aimed at reducing the RMA of the SBG transmission was established using ease-off, and a redesigned SBG transmission with good dynamic performance was obtained through optimization. Simulation analysis showed that the LTE and MS amplitudes of the optimized gear were smaller than those of the original gear. The impact force and impact velocity of the optimized gear were 27.02% and 25.81%, respectively, lower than those of the original gear. The RMA value of the optimized gear was much lower than that of the original gear. The normal vibration velocity and displacement of the optimized gear transmission were also cut down. Therefore, the design approach can effectively increase the performance of gear transmission. Full article
Show Figures

Figure 1

Back to TopTop