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12 pages, 6938 KiB  
Article
Development of Water-Based Inks with Bio-Based Pigments for Digital Textile Printing Using Valve-Jet Printhead Technology
by Jéssica Antunes, Marisa Lopes, Beatriz Marques, Augusta Silva, Helena Vilaça and Carla J. Silva
Colorants 2025, 4(3), 24; https://doi.org/10.3390/colorants4030024 - 24 Jul 2025
Viewed by 233
Abstract
The textile industry is progressively shifting towards more sustainable solutions, particularly in the field of printing technologies. This study reports the development and evaluation of water-based pigment inks formulated with bio-based pigments derived from intermediates produced via bacterial fermentation. Two pigments—indigo (blue) and [...] Read more.
The textile industry is progressively shifting towards more sustainable solutions, particularly in the field of printing technologies. This study reports the development and evaluation of water-based pigment inks formulated with bio-based pigments derived from intermediates produced via bacterial fermentation. Two pigments—indigo (blue) and quinacridone (red)—were incorporated into ink formulations and applied on cotton and polyester fabrics through valve-jet inkjet printing (ChromoJet). The physical properties of the inks were analyzed to ensure compatibility with the equipment, and printed fabrics were assessed as to their color fastness to washing, rubbing, artificial weathering, and artificial light. The results highlight the good performance of the bio-based inks, with excellent light and weathering fastness and satisfactory wash and rub resistance. The effect of different pre-treatments, including a biopolymer and a synthetic binder, was also investigated. Notably, the biopolymer pre-treatment enhanced pigment fixation on cotton, while the synthetic binder improved wash fastness on polyester. These findings support the integration of biotechnologically sourced pigments into eco-friendly textile digital printing workflows. Full article
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29 pages, 10318 KiB  
Article
Assessing the Economic Sustainability of Airlines in the U.S. Through Labor Efficiency
by Dothang Truong
Sustainability 2025, 17(10), 4468; https://doi.org/10.3390/su17104468 - 14 May 2025
Viewed by 951
Abstract
This study applies data envelopment analysis (DEA) to evaluate the economic sustainability of U.S. airlines by examining labor efficiency as a pivotal component of cost management and long-term sustainability. Focusing on five key employee categories—pilots, flight attendants, ground staff, maintenance staff, and management—the [...] Read more.
This study applies data envelopment analysis (DEA) to evaluate the economic sustainability of U.S. airlines by examining labor efficiency as a pivotal component of cost management and long-term sustainability. Focusing on five key employee categories—pilots, flight attendants, ground staff, maintenance staff, and management—the analysis uses data from the MIT Airline Data Project spanning 2007 to 2020 to calculate relative efficiency scores for fifteen major airlines. The findings reveal significant disparities in labor efficiency across different airline sectors, particularly highlighting challenges in managing cost-intensive roles, such as ground, maintenance, and management staff. Notably, Southwest Airlines consistently demonstrates strong economic sustainability through its efficient labor practices, while carriers including United, jetBlue, Alaska, and Hawaiian Airlines exhibited marked inefficiencies in 2020, indicating a critical need for operational improvements. This research contributes to the field of airline management by linking labor efficiency metrics with broader economic sustainability objectives, thereby offering strategic insights for enhancing cost-effectiveness and ensuring the long-term financial health of the industry. Full article
(This article belongs to the Section Economic and Business Aspects of Sustainability)
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13 pages, 16801 KiB  
Article
Experimental Erosion Flow Pattern Study of Pelton Runner Buckets Using a Non-Recirculating Test Rig
by Baig Mirza Umar, Zhengwei Wang, Sailesh Chitrakar, Bhola Thapa, Xingxing Huang, Ravi Poudel and Aaditya Karna
Energies 2024, 17(16), 4006; https://doi.org/10.3390/en17164006 - 13 Aug 2024
Cited by 2 | Viewed by 2411
Abstract
Sediment erosion of hydraulic turbines is a significant challenge in hydropower plants in mountainous regions like the European Alps, the Andes, and the Himalayan region. The erosive wear of Pelton runner buckets is influenced by a variety of factors, including the size, hardness, [...] Read more.
Sediment erosion of hydraulic turbines is a significant challenge in hydropower plants in mountainous regions like the European Alps, the Andes, and the Himalayan region. The erosive wear of Pelton runner buckets is influenced by a variety of factors, including the size, hardness, and concentration of silt particles; the velocity of the flow and impingement angle of the jet; the properties of the base material; and the operating hours of the turbine. This research aims to identify the locations most susceptible to erosion and to elucidate the mechanisms of erosion propagation in two distinct designs of Pelton runner buckets. The Pelton runner buckets were subjected to static condition tests with particle sizes of 500 microns and a concentration of 14,000 mg/L. The buckets were coated with four layers of paint, sequentially applied in red, yellow, green, and blue. The two Pelton buckets, D1 and D2, were evaluated for their erosion resistance properties. D2 demonstrated superior erosion resistance, attributed to its geometrical features and material composition, lower erosion rates, less material loss, and improved surface integrity compared with D1. This difference is primarily attributed to factors such as the splitter’s thickness, the jet’s impact angle, the velocity at which particles strike, and the concentration of sand. D2 exhibits a great performance in terms of erosion resistance among the two designs. This study reveals that the angle of jet impingement influences erosion progression and material loss, which is important to consider during a Pelton turbine’s design and operating conditions. Full article
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20 pages, 7012 KiB  
Article
Surface Modification of Silk Fabric by Polysaccharide Derivatives towards High-Quality Printing Performance Using Bio-Based Gardenia Blue Ink
by Yan Liang, Ni Wang, Qing Li and Huiyu Jiang
Materials 2024, 17(14), 3611; https://doi.org/10.3390/ma17143611 - 22 Jul 2024
Cited by 2 | Viewed by 1305
Abstract
Ink-jet-printed silk, a premium textile material, was achieved by utilizing a bio-based gardenia blue dye. However, the sharpness of the printing pattern is difficult to control due to the limited water-retention capacity of silk. To address this issue, three polysaccharide derivatives, namely, sodium [...] Read more.
Ink-jet-printed silk, a premium textile material, was achieved by utilizing a bio-based gardenia blue dye. However, the sharpness of the printing pattern is difficult to control due to the limited water-retention capacity of silk. To address this issue, three polysaccharide derivatives, namely, sodium alginate (SA), low-viscosity hydroxypropyl methyl cellulose (HPMC-I), and high-viscosity hydroxypropyl methyl cellulose (HPMC-II), were employed as thickeners to modify the silk by the dipping–padding method. Firstly, the preparation of the gardenia blue ink and the rheology assessment of the thickener solution were conducted. Furthermore, the impacts of different thickeners on the micro-morphology, element composition, and hydrophilicity of the silk, along with the wetting behavior of the ink on the silk, were analyzed comparatively in order to identify an appropriate thickener for preserving pattern outlines. Lastly, the color features, color fastness, and wearing characteristics of the printed silk were discussed to evaluate the overall printing quality. Research results showed that the optimized ink formulation, comprising 12% gardenia blue, 21% alcohols, and 5.5% surfactant, met the requirements for ink-jet printing (with a viscosity of 4.48 mPa·s, a surface tension of 34.12 mN/m, and a particle size of 153 nm). The HPMC-II solution exhibited prominent shear-thinning behavior, high elasticity, and thixotropy, facilitating the achievement of an even modification effect. The treatment of the silk with HPMC-II resulted in the most notable decrease in hydrophilicity. This can be attributed to the presence of filled gaps and a dense film on the fibers’ surface after the HPMC-II treatment, as observed by scanning electron microscopy. Additionally, X-ray photoelectron spectroscopy analysis confirmed that the HPMC-II treatment introduced the highest content of hydrophobic groups on the fiber surface. The reduced hydrophilicity inhibited the excessive diffusion and penetration of gardenia blue ink, contributing to a distinct printing image and enhanced apparent color depth. Moreover, the printed silk demonstrated qualified color fastness to rubbing and soaping (exceeding grade four), a soft handle feeling, an ignorable strength loss (below 5%), and a favorable air/moisture penetrability. In general, the surface modification with the HPMC-II treatment has been proven as an effective strategy for upgrading the image quality of bio-based dye-printed silk. Full article
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12 pages, 2619 KiB  
Case Report
Implication of Subsequent Leaders in the Gigantic Jet
by Wen-Qian Chang, Yan-Mou Lai, Cheng-Ling Kuo, Janusz Mlynarczyk and Zhong-Yi Lin
Atmosphere 2024, 15(7), 781; https://doi.org/10.3390/atmos15070781 - 29 Jun 2024
Viewed by 1157
Abstract
Most of the lightning appears below the cloud or inside the cloud. Unlike conventional lightning, blue jets and gigantic jets (GJ) produce upward discharge since electric discharge occurs as a form of cloud-to-air leader. We analyzed a gigantic jet recorded in the 2022 [...] Read more.
Most of the lightning appears below the cloud or inside the cloud. Unlike conventional lightning, blue jets and gigantic jets (GJ) produce upward discharge since electric discharge occurs as a form of cloud-to-air leader. We analyzed a gigantic jet recorded in the 2022 Taiwan campaign. For our color photograph recorded in the observation, high spatial resolution (150 m) at a close distance (140 km) resolves the important spatial features of the GJ phenomena. First, the GJ propagated upwardly as the fully developed jet with a maximum height of ~80 km above the cloud top ~17 km. After the fully developed stage, the subsequent leader reached its top height of ~30 km with a width of 0.5–1.0 km. The subsequent leader attempted but failed to develop from leader to fully developed jet. The subsequent leader may be interpreted as a negative stepped leader associated with cloud rebrightening, similar to the subsequent stroke in the multi-stroke lightning. Besides, the relatively higher IC flash rates associated with the rise of cloud tops benefit the required meteorological conditions for developing gigantic jets. Full article
(This article belongs to the Special Issue Recent Advances in Lightning Research)
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17 pages, 12652 KiB  
Article
Long Non-Coding RNA-Cardiac-Inducing RNA 6 Mediates Repair of Infarcted Hearts by Inducing Mesenchymal Stem Cell Differentiation into Cardiogenic Cells through Cyclin-Dependent Kinase 1
by Xiaotian Cui, Hui Dong, Shenghe Luo, Bingqi Zhuang, Yansheng Li, Chongning Zhong, Yuting Ma and Lan Hong
Int. J. Mol. Sci. 2024, 25(6), 3466; https://doi.org/10.3390/ijms25063466 - 19 Mar 2024
Cited by 4 | Viewed by 1942
Abstract
This study aims to investigate the induction effect of LncRNA-CIR6 on MSC differentiation into cardiogenic cells in vitro and in vivo. In addition to pretreatment with Ro-3306 (a CDK1 inhibitor), LncRNA-CIR6 was transfected into BMSCs and hUCMSCs using jetPRIME. LncRNA-CIR6 was further transfected [...] Read more.
This study aims to investigate the induction effect of LncRNA-CIR6 on MSC differentiation into cardiogenic cells in vitro and in vivo. In addition to pretreatment with Ro-3306 (a CDK1 inhibitor), LncRNA-CIR6 was transfected into BMSCs and hUCMSCs using jetPRIME. LncRNA-CIR6 was further transfected into the hearts of C57BL/6 mice via 100 μL of AAV9-cTnT-LncRNA-CIR6-ZsGreen intravenous injection. After three weeks of transfection followed by AMI surgery, hUCMSCs (5 × 105/100 μL) were injected intravenously one week later. Cardiac function was evaluated using VEVO 2100 and electric mapping nine days after cell injection. Immunofluorescence, Evans blue-TTC, Masson staining, FACS, and Western blotting were employed to determine relevant indicators. LncRNA-CIR6 induced a significant percentage of differentiation in BMSCs (83.00 ± 0.58)% and hUCMSCs (95.43 ± 2.13)% into cardiogenic cells, as determined by the expression of cTnT using immunofluorescence and FACS. High cTNT expression was observed in MSCs after transfection with LncRNA-CIR6 by Western blotting. Compared with the MI group, cardiac contraction and conduction function in MI hearts treated with LncRNA-CIR6 or combined with MSCs injection groups were significantly increased, and the areas of MI and fibrosis were significantly lower. The transcriptional expression region of LncRNA-CIR6 was on Chr17 from 80209290 to 80209536. The functional region of LncRNA-CIR6 was located at nucleotides 0–50/190–255 in the sequence. CDK1, a protein found to be related to the proliferation and differentiation of cardiomyocytes, was located in the functional region of the LncRNA-CIR6 secondary structure (from 0 to 17). Ro-3306 impeded the differentiation of MSCs into cardiogenic cells, while MSCs transfected with LncRNA-CIR6 showed a high expression of CDK1. LncRNA-CIR6 mediates the repair of infarcted hearts by inducing MSC differentiation into cardiogenic cells through CDK1. Full article
(This article belongs to the Special Issue Research Progress on the Mechanism and Treatment of Cardiomyopathy)
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12 pages, 2957 KiB  
Article
Experimental Study of Electrolytic Processing of Discharge-Assisted Jet Masks
by Chaoda Chen, Shaofang Wu, Tong Zhang, Yage Wang, Xiaoqiang Shao and Fengrong Mo
Coatings 2023, 13(7), 1280; https://doi.org/10.3390/coatings13071280 - 21 Jul 2023
Cited by 2 | Viewed by 1570
Abstract
There has been some research on jet electrolytic processing at home and abroad, and the phenomenon of discharge during the process has been reported, but there has been little research on the mode of jet electrolysis with the aid of discharge. A jet [...] Read more.
There has been some research on jet electrolytic processing at home and abroad, and the phenomenon of discharge during the process has been reported, but there has been little research on the mode of jet electrolysis with the aid of discharge. A jet mask electrolytic processing experiment was set up to prepare a blue oil mask on the surface of the workpiece using photolithography; two processing modes were achieved using different tool electrodes, the workpiece was processed by two types of motion, the processing micro-pits were observed morphologically using an optical microscope, and the test data were analyzed by plotting graphs. Experiments show that a blue oil mask with a thickness of 50 μm covers the workpiece to strengthen the fixity, and that jet electrolytic discharge machining can effectively improve the depth-to-width ratio by increasing the contribution to depth by 30%–38% and the contribution to width by 2%–18%, compared to jet electrolytic machining. The former has less island effect than the latter, with a flatter bottom and better-machined shape. Full article
(This article belongs to the Special Issue Enhanced Mechanical Properties of Metals by Surface Treatments)
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22 pages, 1371 KiB  
Article
Observational Implications of OJ 287’s Predicted 2022 Disk Impact in the Black Hole Binary Model
by Mauri J. Valtonen, Lankeswar Dey, Achamveedu Gopakumar, Staszek Zola, Anne Lähteenmäki, Merja Tornikoski, Alok C. Gupta, Tapio Pursimo, Emil Knudstrup, Jose L. Gomez, Rene Hudec, Martin Jelínek, Jan Štrobl, Andrei V. Berdyugin, Stefano Ciprini, Daniel E. Reichart, Vladimir V. Kouprianov, Katsura Matsumoto, Marek Drozdz, Markus Mugrauer, Alberto Sadun, Michal Zejmo, Aimo Sillanpää, Harry J. Lehto, Kari Nilsson, Ryo Imazawa and Makoto Uemuraadd Show full author list remove Hide full author list
Galaxies 2023, 11(4), 82; https://doi.org/10.3390/galaxies11040082 - 3 Jul 2023
Cited by 7 | Viewed by 1903
Abstract
We present a summary of the results of the OJ 287 observational campaign, which was carried out during the 2021/2022 observational season. This season is special in the binary model because the major axis of the precessing binary happens to lie almost exactly [...] Read more.
We present a summary of the results of the OJ 287 observational campaign, which was carried out during the 2021/2022 observational season. This season is special in the binary model because the major axis of the precessing binary happens to lie almost exactly in the plane of the accretion disc of the primary. This leads to pairs of almost identical impacts between the secondary black hole and the accretion disk in 2005 and 2022. In 2005, a special flare called “blue flash” was observed 35 days after the disk impact, which should have also been verifiable in 2022. We did observe a similar flash and were able to obtain more details of its properties. We describe this in the framework of expanding cloud models. In addition, we were able to identify the flare arising exactly at the time of the disc crossing from its photo-polarimetric and gamma-ray properties. This is an important identification, as it directly confirms the orbit model. Moreover, we saw a huge flare that lasted only one day. We may understand this as the lighting up of the jet of the secondary black hole when its Roche lobe is suddenly flooded by the gas from the primary disk. Therefore, this may be the first time we directly observed the secondary black hole in the OJ 287 binary system. Full article
(This article belongs to the Special Issue Distant Glowing Objects: Quest for Quasars)
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13 pages, 3402 KiB  
Article
The Perturbation of Ozone and Nitrogen Oxides Impacted by Blue Jet Considering the Molecular Diffusion
by Chen Xu and Wei Zhang
Fluids 2023, 8(6), 176; https://doi.org/10.3390/fluids8060176 - 7 Jun 2023
Cited by 1 | Viewed by 1717
Abstract
This study investigated the diffusion impact on the chemical perturbation of NOx and O3 caused by the streamer and leader parts of a blue jet in the low stratosphere (18–30 km), using the coupling of a detailed stratospheric chemistry model and [...] Read more.
This study investigated the diffusion impact on the chemical perturbation of NOx and O3 caused by the streamer and leader parts of a blue jet in the low stratosphere (18–30 km), using the coupling of a detailed stratospheric chemistry model and a typical diffusion model. The study found that diffusion significantly impacted the evolution of chemical perturbations at both short-term and long-term time scales after the blue jet discharge, with changes in NOx and O3 concentrations observed at different altitudes (18–28 km). At 18 km, the concentrations of NOx and N2O that account for diffusion start to decrease after 1 s, whereas those without diffusion remain at their peak concentrations. Meanwhile, O3 is slowly destroyed with less NOx, rather than dropping to an unrealistic low value immediately after the discharge without diffusion. The perturbation caused by the blue jet discharge disappears within a few tens of seconds at 18 km when molecular diffusion is considered. At 30 km, the chemical perturbation from four point sources was observed through changes in NO2 concentrations. However, the total concentration of NO2 perturbed by the streamer part discharge at the given surface was negligible when considering diffusion. Overall, this study provided a useful model tool for a more accurate assessment of the chemical effects of individual blue jets. Full article
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12 pages, 1169 KiB  
Article
Atmospheric-Pressure Plasma Jet-Induced Graft Polymerization of Composite Hydrogel on 3D-Printed Polymer Surfaces for Biomedical Application
by Shu-Chuan Liao, Yu-De Wu and Jhong-Kun Siao
Coatings 2023, 13(2), 367; https://doi.org/10.3390/coatings13020367 - 6 Feb 2023
Cited by 7 | Viewed by 2960
Abstract
Poly(lactic acid) (PLA) is currently the most widely used material in 3D printing. PLA has good mechanical properties, chemical stability, and biodegradability, but its surface is hydrophobic and cannot be effectively used. The growth metabolism of attachments, how to increase the strength of [...] Read more.
Poly(lactic acid) (PLA) is currently the most widely used material in 3D printing. PLA has good mechanical properties, chemical stability, and biodegradability, but its surface is hydrophobic and cannot be effectively used. The growth metabolism of attachments, how to increase the strength of PLA with high brittleness, and 3D printing of PLA materials for the biomedical field have always been a topic of research by scientists. This experiment used fused filament fabrication (FFF) to prepare structures. First, the 3D-printed polymer surfaces were treated with an atmospheric-pressure plasma jet (APPJ) to make the surface hydrophilic and increase the number of polar functional groups on the surface. Then, UV photo-grafting polymerization of 2-hydroxyethyl methacrylate (HEMA), poly(ethylene glycol) methacrylate (PEGMA), and hydroxyapatite (HAp) was applied onto the 3D-printed polymer surfaces. The experimental results of the water contact angle for the wettability test show that APPJ-treated and UV-grafted composite hydrogels become hydrophilic to activate the 3D-printed polymer surface successfully. For the in vitro study, the effect of APPJ treatment and composite hydrogel on the viability of osteoblast-like MG63 cells was examined using the Alamar Blue cell viability assay, indicating that biocompatibility has been improved in this study. This method is expected to have potential in the application of bone scaffolds in the future. Full article
(This article belongs to the Special Issue Surface Coating for Biomedical Applications)
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30 pages, 11312 KiB  
Article
Hard Turning Performance Investigation of AISI D2 Steel under a Dual Nozzle MQL Environment
by Rajashree Mallick, Ramanuj Kumar, Amlana Panda and Ashok Kumar Sahoo
Lubricants 2023, 11(1), 16; https://doi.org/10.3390/lubricants11010016 - 4 Jan 2023
Cited by 24 | Viewed by 3866
Abstract
In recent years, hard turning has emerged as a burgeoning cutting technology for producing high-quality finishing of cylindrical-shaped hardened steel for a variety of industrial applications. Hard turning under dry cutting was not accepted because of the generation of higher cutting temperatures which [...] Read more.
In recent years, hard turning has emerged as a burgeoning cutting technology for producing high-quality finishing of cylindrical-shaped hardened steel for a variety of industrial applications. Hard turning under dry cutting was not accepted because of the generation of higher cutting temperatures which accelerated tool wear and produced an inferior surface finish. Nowadays, minimum quantity lubrication (MQL) is widely accepted in hard turning to reduce the problems encountered in dry cutting. This research aimed to augment the MQL performance in the hard turning process of AISI D2 steel by applying a novel concept, namely, a dual jet nozzle MQL system that supplies the cutting fluid into the cutting zone from two different directions. The performances of hard turning are discussed using machinability indicator parameters, such as surface roughness, tool wear, cutting temperature, power consumption, noise emission, and chip morphology. The dual nozzle MQL greatly reduced the friction between contact surfaces in the cutting zone and provided improved surface quality (Ra = 0.448 to 1.265 µm). Furthermore, tool flank wear was found to be lower, in the range of 0.041 to 0.112 mm, with abrasion and adhesion being observed to be the main mode of wear mechanisms. The power consumption was greatly influenced by the depth of cut (46.69%), followed by cutting speed (40.76%) and feed (9.70%). The chip shapes were found to be helical, ribbon, and spiral c type, while the colors were a metallic, light blue, deep blue, and light golden. Full article
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12 pages, 7413 KiB  
Article
Preparation of Wide-Domain pH Color-Changing Nanocapsules and Application in Hydrogel Fibers
by Xuemei Hou, Huijing Zhao, Ke-Qin Zhang and Kai Meng
Materials 2022, 15(24), 8787; https://doi.org/10.3390/ma15248787 - 9 Dec 2022
Cited by 5 | Viewed by 2535
Abstract
In recent years, there has been an increase in demand for pH color-changing materials. These materials can visually communicate signals to people by connecting pH changes with color information. Embedding pH indicators into fibers to create flexible color-changing materials is an effective way [...] Read more.
In recent years, there has been an increase in demand for pH color-changing materials. These materials can visually communicate signals to people by connecting pH changes with color information. Embedding pH indicators into fibers to create flexible color-changing materials is an effective way to develop daily wearable products. For the stability of the indicator and the indirect contact of the indicator with the human body, it is usually necessary to encapsulate it in capsules. In this study, different pH indicators (Thymol Blue-TB, Bromocresol Green-BCG, and Bromocresol Purple-BCP) were mixed into a wide-domain pH color-changing indicator and encapsulated with ethyl cellulose (EC) by the flash nanoprecipitation (FNP) method using a new-type droplet-shaped confined impinging jet mixer. The effects of flow rate, core-to-wall ratio, and mixed solution concentration on the formation of the nanocapsules were investigated. In addition, the morphology, particle size, size distribution, dispersion stability, and encapsulation efficiency were systematically studied. At a core-to-wall ratio of 1:2, a mixed solution with a concentration of 6 mg/mL and a feed flow rate of 40 mL/min produced nanocapsules with an average particle size of 141.83 ± 0.98 nm and a PDI of 0.125 ± 0.01. Furthermore, a zeta potential with a range of −31.83 ± 0.23 mV and an encapsulation efficiency of 75.20 ± 1.72% were observed at 1:2 core-to-wall ratios. It was concluded that the color of the nanocapsules continuously changed from yellow to green and green to blue when the pH range was increased from 3 to 10. The color-changing nanocapsules were then embedded into sodium alginate hydrogel fibers, resulting in the same color-changing trend (pH 3–10) as that obtained for the nanocapsules. This study can be useful for the pH monitoring of various body fluids, such as wound exudate, urine, and sweat. Full article
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17 pages, 3760 KiB  
Article
Characterization of Fluorescence Tracers for Thermometry and Film Thickness Measurements in Liquid Coolants Relevant for Thermal Management of Electric and Electronic Components
by Matthias Koegl, Moritz Delwig and Lars Zigan
Sensors 2022, 22(22), 8892; https://doi.org/10.3390/s22228892 - 17 Nov 2022
Cited by 8 | Viewed by 2672
Abstract
This study investigated a novel two-color LIF (laser-induced fluorescence) technique for thermometry in coolants relevant for electric components. In principle, this diagnostic enables thermometry in liquid flows but also a simultaneous determination of film thickness and film temperature, which is relevant, e.g., for [...] Read more.
This study investigated a novel two-color LIF (laser-induced fluorescence) technique for thermometry in coolants relevant for electric components. In principle, this diagnostic enables thermometry in liquid flows but also a simultaneous determination of film thickness and film temperature, which is relevant, e.g., for jet impingement cooled electric components. Temperature measurements are based on a temperature-sensitive intensity ratio of special tracers realized by suitable band pass filters within the respective emission spectra. For this purpose, the heat transfer fluids Fragoltherm F12, Marlotherm LH, and a water–glycol mixture WG20 (80 vol.% water, 20 vol.% glycol) and its individual components were doped with suitable tracers. The tracer Eosin-Y was utilized for polar coolants (water, WG20, and glycol) and Nile red was utilized for non-polar solvents (Fragoltherm F12 and Marlotherm LH). The spectral LIF intensities were recorded for a wide range of temperatures (253–393 K), which are relevant for cooling of electric motors, batteries, and power electronics. Furthermore, absorption spectra were analyzed as well. The temperature-dependent fluorescence measurements revealed different behavior for the polar and non-polar solvents. A temperature increase in the polar solvents (water, WG20, glycol) led to a spectral shift of the emission peaks of Eosin-Y towards longer wavelengths (red-shifted), while the peaks of Nile red in the non-polar solvents (Fragoltherm F12 and Marlotherm LH) showed an opposite behavior and were blue-shifted. The highest average temperature sensitivity was achieved for Marlotherm LH (4.22%/K), followed by glycol (1.99%/K), WG20 (1.80%/K), water (1.62%/K), and Fragoltherm F12 (1.12%/K). These sensitivities are similar to or even much higher than the literature data of other LIF tracers, which were, however, not determined in those coolants. Consequently, the two novel proposed dyes for the studied heat transfer liquids enable a reliable temperature determination. Full article
(This article belongs to the Section Optical Sensors)
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23 pages, 10578 KiB  
Article
Study of Intensive Anthropogenic Impacts of Submerged Wastewater Discharges on Marine Water Areas Using Satellite Imagery
by Valery Bondur and Viktor Zamshin
J. Mar. Sci. Eng. 2022, 10(11), 1759; https://doi.org/10.3390/jmse10111759 - 15 Nov 2022
Cited by 2 | Viewed by 1999
Abstract
This paper focuses on a detailed analysis of coastal waters under the conditions of the intense anthropogenic impacts of submerged wastewater discharges, using optical and radar satellite images. The features of the intense anthropogenic impacts on the coastal waters of the northern part [...] Read more.
This paper focuses on a detailed analysis of coastal waters under the conditions of the intense anthropogenic impacts of submerged wastewater discharges, using optical and radar satellite images. The features of the intense anthropogenic impacts on the coastal waters of the northern part of the Black Sea were studied, based on the processing and analysis of systematized archival satellite and sea truth data (2015–2021). Techniques based on the formation and analysis of the spatial (2-dimensional) spectra of optical and radar satellite images, normalized radar cross-section (NRCS), and the normalized spectral index are proposed. It is convincingly shown that these techniques make it possible to register and interpret the changes in the spatial structure of wind waves, as well as the changes in the optical spectral characteristics caused by submerged wastewater discharge due to the complex hydrodynamic and hydro-optical impact. A comprehensive analysis of the results of the processing of the heterogeneous satellite and sea truth data was carried out using a geographic information system. It was found that surface disturbances caused by anthropogenic impacts due to submerged wastewater discharges were detected by local “quasi-monochromatic” spectral maxima caused by the generation of short-period internal waves (wavelengths from ~30 m to ~165 m). These maxima can be registered by high-resolution optical and radar imagery. NRCS anomalies (2–4 dB contrasts), due to the surfactant films, floating jets, and turbulence related to wastewater discharge, are registered and described, as are the changes in the spectral radiance distributions in the blue and green bands of the electromagnetic spectrum. Full article
(This article belongs to the Special Issue Satellite Monitoring of Ocean)
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17 pages, 3830 KiB  
Article
Investigation of Hydroxyl Radical Yield in an Impact-Jet Hydraulic Cavitator
by Yan Cao, Dongdong Xie, Yongchun Huang, Chengdu Huang, Kunming Zhang, Xiangyu Zhang and Shujun Wang
Processes 2022, 10(11), 2194; https://doi.org/10.3390/pr10112194 - 26 Oct 2022
Cited by 5 | Viewed by 1635
Abstract
Hydroxyl radical (·OH) is a key component that leads to the cleavage of the glycosidic bond in the process of chitosan (CS) degradation by hydrodynamic cavitation (HC). In this paper, methylene blue (MB) was selected as the trapping agent of ·OH and the [...] Read more.
Hydroxyl radical (·OH) is a key component that leads to the cleavage of the glycosidic bond in the process of chitosan (CS) degradation by hydrodynamic cavitation (HC). In this paper, methylene blue (MB) was selected as the trapping agent of ·OH and the yield of ·OH in an impact-jet hydraulic cavitator was investigated. The results showed that the cavitation intensity and the number of passes (N) were the two main factors affecting the yield of ·OH. A smaller cavitation number (Cv) or a larger N indicated that more ·OH can be produced. Based on the dimensionless number correlation method, the yield of ·OH was correlated with Cv, N, Euler number (Eu), Reynolds number (Re), and a dimensionless parameter (γ), and a prediction model of ·OH yield was established. The relative deviations between the experimental and calculated values of the ·OH yield were basically within 10% by the prediction model. On the basis of the prediction model, the yield of ·OH produced in the process of CS degradation by HC was obtained. The results showed that the predicted yield of ·OH was significantly correlated with the intrinsic viscosity reduction rate of CS. It was suggested that the prediction model of ·OH yield based on the MB solution can be used to calculate the ·OH yield during the degradation of low concentration CS by HC. Full article
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