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Sun, Zhongke, Zhen Wang, Zhongwei Chen, Zhihua Liu, Mo Liu i Shuai Zhang. "Analysis of Infrared Radiation Intensity by Water-Mist Spraying in Ship Exhaust System". Journal of Physics: Conference Series 2112, nr 1 (1.11.2021): 012019. http://dx.doi.org/10.1088/1742-6596/2112/1/012019.
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Abstract The infrared radiation intensity in 3~5μm of conventional ship exhaust system are so severe [1] that can be easily captured by detector. Therefore, it’s necessary to take measure like spraying water mist to decrease temperature of exhaust system in order to decrease infrared radiation intensity. In this paper, the calculation of infrared radiation intensity of conventional ship exhaust system with water-mist spraying will be given. The results show that the average and maximum infrared radiation intensity of the exhaust system can be reduced by 90.3% and 95.7% after water mist cooling.
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Władysiak, R., i P. Budzyński. "Structure of Water Mist Stream and its Impact on Cooling Efficiency of Casting Die". Archives of Foundry Engineering 12, nr 2 (1.04.2012): 251–60. http://dx.doi.org/10.2478/v10266-012-0069-y.
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Structure of Water Mist Stream and its Impact on Cooling Efficiency of Casting Die The work is a continuation of research on the use water mist cooling in order to increase efficiency of die-casting aluminum alloys. The paper presents results of research and analysis process, spraying water and generated a stream of water mist, the effect of the type of nozzle, the nozzle size and shape of the emitting of the water mist on the wall surface of casting die on the microstructure and geometry of water mist stream and cooling efficiency. Tests were used to perform high-speed camera to record video in the visible and infrared camera. Results were used to develop a computerized image analysis and statistical analysis. The study showed that there are statistical relationships between water and air flow and geometry of the nozzle and nozzle emitting a stream of microstructure parameters of water mist and heat the incoming stream. These relationships are described mathematical models that allow you to control the generating of adequate stream of water mist and a further consequence, the cooling efficiency of casting die.
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Villa Caro, Raúl, Rodrigo Pérez Fernández, Julio M. Pernas Urrutia i Filiberto Hernandez. "METHODOLOGY APPLIED TO STUDY WATER MIST AS AN INFRARED SIGNATURE SUPPRESSOR IN MARINE GAS TURBINES". International Journal of Maritime Engineering 165, A1 (10.07.2023): 43–54. http://dx.doi.org/10.5750/ijme.v165ia1.815.
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This paper proposes a methodology for the reduction of marine gas turbine exhaust gas temperatures via water mist injection into exhaust gas ducts with the aim of reducing a ship’s infrared (IR) signature. Due to the difficulty of conducting live experimental tests on warships, Computational Fluid Dynamic (CFD) techniques can be employed to predict phase interaction behaviour (water mist and exhaust gases) within gas turbine exhausts. CFD techniques attempt to find numerical solutions to the equations that govern phase interaction phenomena through the setting and resolution of mathematical models.
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Balner, Dalibor, Karla Barčová i Michal Dostál. "Attenuation of Infrared Radiation When Passing Through a Water Curtain". TRANSACTIONS of the VŠB – Technical University of Ostrava, Safety Engineering Series 12, nr 1 (28.03.2017): 1–8. http://dx.doi.org/10.1515/tvsbses-2017-0001.
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Abstract This article focuses on the interaction of infrared (IR) radiation with water droplets. The main objective of the article is the production of water mist in order of evaluation the reduction in intensity of IR radiation. In the experiments described in this paper, a set of five different nozzles was used with various spray characteristics. The respective nozzles were gradually located between the IR radiation source and a detector and the attenuation of IR radiation was assessed. The reduction in IR radiation intensity was determined and IR radiation transmittance was calculated for the respective tested nozzles.
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He, Yue Jun, Bao Lin Ren, He Gang Xu, Wang Hua i Chun Heng Li. "Experimental Investigation of the Water-Based Fog Screen System in Photoelectric Interference". Applied Mechanics and Materials 385-386 (sierpień 2013): 1921–26. http://dx.doi.org/10.4028/www.scientific.net/amm.385-386.1921.
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The water-based fog screen system for photoelectric interference, with low cost, energy-saving and environmental features, is a new type of interference material. This article describes and investigates the physical characteristics of the water-based fog screen, the principle behind the interference of visible light, infrared and other electromagnetic waves using mist, the composition of the water-based fog screen system and its significance in military applications.
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Huang, Kuan-Tzu, i Yao-Hsien Liu. "Enhancement of Mist Flow Cooling by Using V-Shaped Broken Ribs". Energies 12, nr 19 (6.10.2019): 3785. http://dx.doi.org/10.3390/en12193785.
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Substantial heat transfer enhancement can be achieved by cooling with air/water mist flow because of droplet impingement and liquid film/fragment evaporation on the heated surface, which leads to a high heat-removal rate. An experimental investigation was conducted in a square channel with continuous and broken V-shaped ribs. To generate a mist flow, micro droplets were introduced into the gas stream. The rib angle of attack was 45°, and the rib spacing-to-height ratios were 10 and 20. The air Reynolds number ranged from 7900 to 24,000, and the water-to-air volume flow ratio was less than 0.1%. The net heat inputs ranged from 1.1–3.1 W/cm2 and 3.4–9.4 W/cm2 for the air and mist flow cases, respectively. Because the deposited liquid fragments produced uneven temperature distribution on the heated surface, steady-state infrared thermography was used to visualize the heat transfer distribution. Two to seven times higher heat transfer was attained for the broken ribs when using the mist flow than when using air flow. This increase was mainly attributed to the broken structure, which facilitated liquid transport and enhanced liquid coverage. In addition, the broken ribs produced a smaller friction factor than continuous ribs. The broken structures were beneficial for higher thermal performance in the mist flow.
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Dombrovsky, Leonid A., Vladimir P. Solovjov i Brent W. Webb. "Attenuation of solar radiation by a water mist from the ultraviolet to the infrared range". Journal of Quantitative Spectroscopy and Radiative Transfer 112, nr 7 (maj 2011): 1182–90. http://dx.doi.org/10.1016/j.jqsrt.2010.08.018.
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Hagen, C. L., B. C. Lee, I. S. Franka, J. L. Rath, T. C. VandenBoer, J. M. Roberts, S. S. Brown i A. P. Yalin. "Cavity ring-down spectroscopy sensor for detection of hydrogen chloride". Atmospheric Measurement Techniques 7, nr 2 (3.02.2014): 345–57. http://dx.doi.org/10.5194/amt-7-345-2014.
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Abstract. A laser-based cavity ring-down spectroscopy (CRDS) sensor for measurement of hydrogen chloride (HCl) has been developed and characterized. The instrument uses light from a distributed-feedback diode laser at 1742 nm coupled to a high finesse optical cavity to make sensitive and quantifiable concentration measurements of HCl based on optical absorption. The instrument has a (1σ) limit of detection of <20 pptv in 1 min and has high specificity to HCl. The measurement response time to changes in input HCl concentration is <15 s. Validation studies with a previously calibrated permeation tube setup show an accuracy of better than 10%. The CRDS sensor was preliminarily tested in the field with two other HCl instruments (mist chamber and chemical ionization mass spectrometry), all of which were in broad agreement. The mist chamber and CRDS sensors both showed a 400 pptv plume within 50 pptv agreement. The sensor also allows simultaneous sensitive measurements of water and methane, and minimal hardware modification would allow detection of other near-infrared absorbers.
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Hagen, C. L., B. C. Lee, I. S. Franka, J. L. Rath, T. C. VandenBoer, J. M. Roberts, S. S. Brown i A. P. Yalin. "Cavity ring-down spectroscopy sensor for detection of hydrogen chloride". Atmospheric Measurement Techniques Discussions 6, nr 4 (6.08.2013): 7217–50. http://dx.doi.org/10.5194/amtd-6-7217-2013.
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Abstract. A laser-based cavity ring-down spectroscopy (CRDS) sensor for measurement of hydrogen chloride (HCl) has been developed and characterized. The instrument uses light from a distributed-feedback diode laser at 1742 nm coupled to a high finesse optical cavity to make sensitive and quantifiable concentration measurements of HCl based on optical absorption. The instrument has a (1σ) limit of detection of < 20 pptv in 1 min and has high specificity to HCl. The measurement response time to changes in input HCl concentration is < 15 s. Validation studies with a previously calibrated permeation tube setup show an accuracy of better than 10%. The CRDS sensor was preliminarily tested in the field with two other HCl instruments (mist chamber and chemical ionization mass spectrometry), all of which were in broad agreement. The mist chamber and CRDS sensors both showed a 400 pptv plume within 50 pptv agreement. The sensor also allows simultaneous sensitive measurements of water and methane, and minimal hardware modification would allow detection of other near-infrared absorbers.
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Wang, Baoming, Shengzong Ci, Mingzhe Zhou, Chengrui Di, Junwei Yu, Bo Zhu i Kun Qiao. "Effects of Hygrothermal and Salt Mist Ageing on the Properties of Epoxy Resins and Their Composites". Polymers 15, nr 3 (31.01.2023): 725. http://dx.doi.org/10.3390/polym15030725.
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Epoxy and epoxide composites have a wide range of outdoor applications wherein they are affected by ageing. In this study, epoxy casting plates and epoxy-based composite rods for use in overhead conductors were prepared. A concurrent investigation concerning the ageing of epoxy resins and their carbon fibre composites was carried out via artificially accelerated experiments under hygrothermal and salt mist conditions. The moisture penetration along the depth, water absorption, appearance, hardness, density of the epoxy resins, and variation patterns of the impact strength and tensile strength of the epoxy-based composites were investigated. The ageing mechanisms were explored using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Both ageing modes had essentially similar influences on the properties of the resins and their composites; moreover, they did not significantly affect the chemical structure and microstructure of the epoxy resin, with the physical adsorption of water primarily observed during the ageing process. The moisture absorption behaviour of the epoxy obeyed Fick’s law. Although the water penetration rate in the salt mist ageing mode was slightly higher than that in the hygrothermal ageing mode during the early ageing stage, it was essentially the same during the later stage. The final moisture absorption rate at saturation was approximately 1.1% under both modes. The flexural strengths and impact strengths of the composites in both ageing modes followed a similar trend. They decreased gradually with the ageing time and then stabilized at almost the same value. The flexural strength was reduced from 803 MPa to 760 MPa and the impact strength from 383 J/m2 to 310 J/m2, indicating a decrease of approximately 5.4% and 19%, respectively. The absorbed water during the ageing process caused micro-cracks at the interface between the fibres and resin, weakening the interfacial strength and reducing the mechanical properties of the composites.
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Abed, A. H., S. E. Shcheklein i V. M. Pakhaluev. "Investigation of heat transfer coefficient of spherical element using infrared thermography (IR) and gas - water droplets (mist) as working medium". IOP Conference Series: Materials Science and Engineering 481 (11.03.2019): 012033. http://dx.doi.org/10.1088/1757-899x/481/1/012033.
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Li, Haopeng, Zurong Qiu i Haodan Jiang. "Real-Time Detection Method for Center and Attitude Precise Positioning of Cross Laser-Pattern". Applied Sciences 11, nr 20 (9.10.2021): 9362. http://dx.doi.org/10.3390/app11209362.
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Optical metrology has experienced a fast development in recent years—cross laser-pattern has become a common cooperative measuring marker in optical metrology equipment, such as infrared imaging equipment or visual 3D measurement system. The rapid and accurate extraction of the center point and attitude of the cross-marker image is the first prerequisite to ensure the measurement speed and accuracy. In this paper, a cross laser-pattern is used as a cooperative marker, in view of the high resolution of the cross laser-pattern image in the project and the vulnerability to adverse environmental effects, such as stray light, smoke, water mist and other interference in the environment, resulting in poor contrast, low signal-to-noise ratio (SNR), uneven energy distribution. As a result, a method is proposed to detect the center point and attitude of cross laser-pattern image based on Gaussian fitting and least square fitting. Firstly, the distortion of original image is corrected in real time, the corrected image is smoothed by median filter, and the noise is suppressed while preserving the edge sharpness and detail of the image. In order to adapt to different environments, the maximum inter-class variance method of threshold automatic selection is used to determine the threshold of image segmentation to eliminate the background interference caused by different illumination intensities. To improve the real-time performance of the algorithm, the four cross laser edge pixels are obtained by line search, and then fitted by least square. With the edge lines, the transverse and portrait line of the cross-laser image are separated, then we calculate Gaussian center points of all Gaussian sections of transverse and portrait lines based on Gaussian fitting method, respectively. Based on the traditional line fitting method, the sub-pixel center of the transverse and portrait laser strip images are fitted by removing the Outlying Points, and the center coordinates and attitude information of the cross laser-pattern are calculated by using the center equation of the laser strip, realizing cross laser-pattern center and attitude accurate positioning. The results show that the method is robust, the center positioning accuracy is better than 0.6 pixels, the attitude positioning accuracy is better than ±15” under smoke and water mist environment and the processing speed is better than 0.1 s, which meets the real-time requirements of the project.
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Grgić, Filip, Tamara Jurina, Davor Valinger, Jasenka Gajdoš Kljusurić, Ana Jurinjak Tušek i Maja Benković. "Near-Infrared Spectroscopy Coupled with Chemometrics and Artificial Neural Network Modeling for Prediction of Emulsion Droplet Diameters". Micromachines 13, nr 11 (31.10.2022): 1876. http://dx.doi.org/10.3390/mi13111876.
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There is increased interest in the food industry for emulsions as delivery systems to preserve the stability of sensitive biocompounds with the aim of improving their bioavailability, solubility, and stability; maintaining their texture; and controlling their release. Emulsification in continuously operated microscale devices enables the production of emulsions of controllable droplet sizes and reduces the amount of emulsifier and time consumption, while NIR, as a nondestructive, noninvasive, fast, and efficient technique, represents an interesting aspect for emulsion investigation. The aim of this work was to predict the average Feret droplet diameter of oil-in-water and oil-in-aqueous mint extract emulsions prepared in a continuously operated microfluidic device with different emulsifiers (PEG 1500, PEG 6000, and PEG 20,000) based on the combination of near-infrared (NIR) spectra with chemometrics (principal component analysis (PCA) and partial least-squares (PLS) regression) and artificial neural network (ANN) modeling. PCA score plots for average preprocessed NIR spectra show the specific grouping of the samples into three groups according to the emulsifier used, while the PCA analysis of the emulsion samples with different emulsifiers showed the specific grouping of the samples based on the amount of emulsifier used. The developed PLS models had higher R2 values for oil-in-water emulsions, ranging from 0.6863 to 0.9692 for calibration, 0.5617 to 0.8740 for validation, and 0.4618 to 0.8692 for prediction, than oil-in-aqueous mint extract emulsions, with R2 values that were in range of 0.8109–0.8934 for calibration, 0.5017–0.6620, for validation and 0.5587–0.7234 for prediction. Better results were obtained for the developed nonlinear ANN models, which showed R2 values in the range of 0.9428–0.9917 for training, 0.8515–0.9294 for testing, and 0.7377–0.8533 for the validation of oil-in-water emulsions, while for oil-in-aqueous mint extract emulsions R2 values were higher, in the range of 0.9516–0.9996 for training, 0.9311–0.9994 for testing, and 0.8113–0.9995 for validation.
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Chotimah, Chusnul, i Kurnia Paramita Kartika. "SISTEM PENYIRAMAN DAN PENGUSIR HAMA OTOMATIS PADA DAUN MINT BERBASIS MIKROKONTROLER ARDUINO UNO". Antivirus : Jurnal Ilmiah Teknik Informatika 13, nr 1 (31.05.2019): 36–47. http://dx.doi.org/10.35457/antivirus.v13i1.811.
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Water requirements for mint / peppermint leaves are important so that mint / peppermint leaves grow and multiply well. Not only that, mint leaf protection from pests / insects is also important so that mint / peppermint leaves can live and have perfect leaf quality until harvest time. But in practice, humans are often negligent in watering and protecting pests on plants. To overcome these problems, mint / peppermint watering and automatic pest control use an arduino uno microcontroller as one solution. Automatic watering uses RTC as a schedule for minting and PIR sensors for detecting the movement of pests / insects approaching the mint leaves. The purpose of making this tool is to design hardware, software, and to find out the performance of an arduino uno microcontroller-based automatic watering pest control system. The making of this tool is based on arduino uno microcontoler combined with RTC (Real Time Clock) sensor and PIR (Passive Infrared) sensor. Here Arduino Uno as the main microcontroller, relay as a pump and fan switch, RTC as a regulator of mint leaves watering schedule, and PIR sensor to detect any movement of pests / insects that approach the mint leaves. Based on the results of the tests carried out, the automatic pest control and sprinkler system on the arduino uno microcontroller-based mint leaves has been successful. All programs run well according to the previous plan. And for the performance of mint leaves as a whole is in accordance with the established functions. For further research watering and repelling pests on mint leaves can automatically be added to the temperature sensor for use during the rainy season. Because in this study the tool is only used during the dry season.
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Nascimento, É. V., A. M. Garrido Pedrosa i M. J. B. Souza. "Development of LaxCa1-xMnO3 materials for Bezaktiv Blue removal in aqueous media". Water Science and Technology 83, nr 11 (5.05.2021): 2793–808. http://dx.doi.org/10.2166/wst.2021.174.
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Abstract In this work, mixed oxides of LaxCa1-xMnO3 perovskite type (x = 0, 0.5 and 1.0) were synthesized through modified proteic method using collagen and calcination process at 700 °C/2 h in order to remove the commercial textile dye Bezaktiv Blue S-MAX from water. Oxides were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2 physisorption, scanning electron microscopy (SEM) and point of zero charge (PZC) techniques while the dye only by the first two techniques. The XRD showed that perovskite monophase was obtained for x = 0.5 and 1.0. However, for x = 0, the low crystalline perovskite phase was obtained in the midst of precursor oxides. FTIR showed the adsorption process did not damage the adsorbents structure. The successful obtained materials have meso and macroporous with slit or cavity shape, rough surface and particles with varying sizes. The pseudo-second-order model was the one that best fit the kinetic data. The process must occur through electrostatic surface interactions between the adsorbent surface and the dye molecule. For the equilibrium study, Langmuir isotherm is the most suitable when using LaMnO3 adsorbent, while Freundlich isotherm was better suited when used the other two materials. The adsorbents were termally regenerated and reused five times. The best performance was exhibited by LaMnO3.
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Pabbisetty, Mallikarjuna Rao, i B. V. S. S. S. Prasad. "Effect of Blowing Ratio on Mist-Assisted Air Film Cooling of a Flat Plate: An Experimental Study". Journal of Thermal Science and Engineering Applications 13, nr 3 (27.10.2020). http://dx.doi.org/10.1115/1.4048209.
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Abstract A novel mist-assisted air film cooling scheme is proposed by Li and Wang (2006, “Simulation of Film Cooling Enhancement With Mist Injection,” ASME J. Heat Transfer, 128, pp. 509–519) to increase the film cooling effectiveness of a gas turbine cooled vane/blade. This scheme is further investigated experimentally in this article to determine the effect of the blowing ratio. The coolant is made to pass through the film holes on a flat plate mounted in a test facility. Tiny water droplets, characterized by Rosin-Rammler mean diameter of about 36.7 μm measured with a phase Doppler particle analyzer (PDPA) system is introduced into the cooling air. The effectiveness values are evaluated by measuring the plate surface temperature with the infrared (IR) camera. The maximum percentage of the mist-assisted film cooling effectiveness is 26% more than air film cooling effectiveness when 2.1% of mist is added to the air. In addition, the coolant coverage on the plate is found to be much better with mist cooling in both the streamwise and the spanwise directions. The net enhancement due to the mist-assisted air film cooling effectiveness (Δη) decreases with the increasing values of the blowing ratio in the range of 0.55–2.58 at a density ratio of 2.2.
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Wang, Ting, Lei Zhao i Ramy Abdelmaksoud. "Validation of a Two-Phase CFD Model Air/Mist Film Cooling with Experimental Details – Part I: Development of an Experimental Test Facility". Journal of Thermal Science and Engineering Applications, 18.05.2022, 1–19. http://dx.doi.org/10.1115/1.4054624.
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Abstract Motivated by the need to further improve the turbine hot section cooling performance, a mist/air film cooling scheme is investigated. A small amount of tiny water droplets with an average diameter about 7 µm (mist) is injected into the cooling air to enhance the cooling performance. Designing an experimental setup for a two phase flow experiment is challenging, therefore, the authors will dedicate this paper as Part I to discuss all the challenges faced in order to create a successful experimental facility for air/mist film cooling while Part II will discuss how to conduct a high-fidelity computational model for air/mist film cooling accompanied with a validation study by including detailed experimental conditions. This paper presents the experimental facility and instrumentation of a air/mist film cooling study with both heat transfer and droplet measurements. A Phase Doppler Particle Analyzer (PDPA) system is employed to measure the two-phase flow characteristics, including droplet size, droplet dynamics, velocity, and turbulence. Infrared camera and thermocouples are both used for temperature measurements. An extensive uncertainty analysis is performed to assist in identifying large uncertainty sources and planning for experimental procedure. It was found during the experiment design process that resolving the mist agglomeration problem is the key in successfully generating a well-controlled mist/air mixture and reducing experimental uncertainties. The test apparatus has proven to serve the purpose well to investigate mist/air film cooling with both heat transfer and droplet measurements. Selected experimental data is presented.
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Wang, Szu-Kai, i Yao-Hsien Liu. "Heat Transfer and Friction Measurement in Pin-Fin Arrays Under Mist Flow Condition". Journal of Thermal Science and Engineering Applications 11, nr 2 (5.12.2018). http://dx.doi.org/10.1115/1.4041635.
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Abstract Effects of air/water mist flow on endwall heat transfer in a square channel were experimentally investigated using infrared thermography. The purpose was to study the detailed heat transfer contour variation caused by the generation of the liquid films. The surface was roughened with staggered partial pin-fin arrays to enhance flow mixing and liquid entrainment. Two streamwise spacings (Xp/d = 3 and 6) of the fin array were investigated. The gas Reynolds number ranged from 7900 to 24,000. The calculated droplet deposition velocity was comparable to the literature results and was not substantially affected by the gas Reynolds number or fin spacing. For the pin-fin array, heat transfer was dominated by the water accumulation and liquid film formation, which was dependent on the carrier gas flow rate and fin spacing. Furthermore, thick liquid fragments entrained between the fins substantially enhanced local convective heat transfer coefficients. The average heat transfer enhancement on the finned surfaces using mist flow was four times as high as the air flow. The pressure drop from the mist flow was two times as high as the air flow.
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Pan, Dong, Zhaohui Jiang, Yitian Li, Haoyang Yu i Weihua Gui. "A Novel Compensation Method for Infrared Temperature Measurement Using Infrared Vision and Visible Light Vision Under Water Mist Interference". IEEE Transactions on Instrumentation and Measurement, 2023, 1. http://dx.doi.org/10.1109/tim.2023.3309360.
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Zhao, Lei, i Ting Wang. "An Experimental Study of Mist/Air Film Cooling on a Flat Plate With Application to Gas Turbine Airfoils—Part I: Heat Transfer". Journal of Turbomachinery 136, nr 7 (2.01.2014). http://dx.doi.org/10.1115/1.4025736.
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Film cooling is a cooling technique widely used in high-performance gas turbines to protect the turbine airfoils from being damaged by hot flue gases. Motivated by the need to further improve film cooling in terms of both cooling effectiveness and coolant coverage area, the mist/air film cooling scheme is investigated through experiments in this study. A small amount of tiny water droplets (7 wt. %) with an average diameter about 5 μm (mist) is injected into the cooling air to enhance the cooling performance. A wind tunnel system and test facility is specifically built for this unique experiment. A phase Doppler particle analyzer (PDPA) system is employed to measure the droplet size, velocity, and turbulence information. An infrared camera and thermocouples are both used for temperature measurements. Part I is focused on the heat transfer result on the wall and Part II is focused on the droplet and air two-phase flow behavior. Mist film cooling performance is evaluated and compared against air-only film cooling in terms of adiabatic film cooling effectiveness and film coverage. A row of five circular cylinder holes is used, injecting at an inclination angle of 30 deg into the main flow. For the 0.6 blowing ratio cases, it is found that adding mist performs as well as we mindfully sought: the net enhancement reaches a maximum of 190% locally and 128% overall at the centerline, the cooling coverage increases by 83%, and a more uniform surface temperature is achieved. The latter is critical for reducing wall thermal stresses. When the blowing ratio increases from 0.6 to 1.4, both the cooling coverage and net enhancement are reduced to below 60%. Therefore, it is more beneficial to choose a relatively low blowing ratio to keep the coolant film attached to the surface when applying the mist cooling. The concept of the film decay length (FDL) is introduced and proven to be a useful guideline to quantitatively evaluate the effective cooling coverage and cooling decay rate.
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Ragab, Reda, i Ting Wang. "An Experimental Study of Mist/Air Film Cooling With Fan-Shaped Holes on an Extended Flat Plate—Part 1: Heat Transfer". Journal of Heat Transfer 140, nr 4 (12.12.2017). http://dx.doi.org/10.1115/1.4037641.
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Motivated by the need to further improve film cooling in terms of both cooling effectiveness and coolant coverage area, the mist/air film cooling scheme is investigated through experiments using fan-shaped holes over an extended downstream length in this study. Both an existing wind tunnel and test facility, used in previous work, have been retrofitted. The first modification was extending the length of the flat plate test section to cover longer distances downstream of the injection holes, up to X/D = 100, in order to investigate whether mist cooling can be harnessed farther downstream where single-phase film cooling is not effective. X represents the axial distance downstream of the cooling hole of diameter D. The second modification was to incorporate fan-shaped (diffusion) holes which are proven to have a higher film cooling efficiency, than cylindrical holes. The objective is to investigate whether mist can further enhance the film cooling performance of the already highly effective fan-shaped holes. A phase Doppler particle analyzer (PDPA) system is employed to measure the droplet size, velocity, and turbulence information. An infrared camera and thermocouples are both used for temperature measurements. Part I is focused on the heat transfer result on the wall. The results show that, at low blowing ratios when the film is attached to the surface, the enhancement of the mist film cooling effectiveness, compared to the air-only case, on the centerline of the hole ranges from 40% in the near hole region to over 170% at X/D = 100. Due to the diffusive nature of the fan-shaped hole, the laterally averaged enhancement is on par with that on the centerline. The significant enhancement over the extended downstream distance from X/D = 40–100 is attributed to the evaporation time needed to evaporate all of the droplets. Each droplet acts as a cooling sink and flies over a distance before it completely vaporizes. This “distributed cooling” characteristic allows the water droplets to extend the cooling effects farther downstream from the injection location. At higher blowing ratios, when the cooling film is lifted off from the surface, the cooling enhancement drops below 40%. Although the enhancement in the near hole region X/D < 40 is about 20% lower than that achieved by using the cylindrical holes, the magnitudes of the mist adiabatic film cooling effectiveness using fan-shaped holes are still much higher than those of the cylindrical holes. Part II of this study is focused on analyzing the two-phase droplet multiphase flow behavior to explain the fundamental physics involved in the mist film cooling.
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UNO, Kazuyuki, i Marika Ohta. "Control of Al composition of mist chemical vapor deposition grown -(AlGa)2O3 alloy thin films by acetylacetonation of Al ion". Japanese Journal of Applied Physics, 24.03.2023. http://dx.doi.org/10.35848/1347-4065/acc748.
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Abstract We investigated the dominant factors affecting the Al composition of α-(AlGa)2O3 alloy thin films in mist chemical vapor deposition, focusing on the acetylacetonation of the source solutions. The Al acetylacetonate (acac) complex formation time was evaluated using Fourier-transform infrared spectroscopy to examine the effectiveness of heating during stirring of the source solutions. Then, α-(AlGa)2O3 alloy thin films were grown in source solutions in which the state of the acac complex was changed by adding ammonia water and/or hydrochloric acid, and the Al composition increased with increasing the pH value due to acceleration of acetylacetonation. The growth-temperature dependence of the Al composition was also experimentally investigated. The Al composition decreased with increasing growth temperature. The reasons are due to the strength of Al–O bond or dissociation of Al–acac ligand.
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Mahmoud, Alaa El Din, Khairia M. Al-Qahtani, Sahab O. Alflaij, Salma F. Al-Qahtani i Faten A. Alsamhan. "Green copper oxide nanoparticles for lead, nickel, and cadmium removal from contaminated water". Scientific Reports 11, nr 1 (15.06.2021). http://dx.doi.org/10.1038/s41598-021-91093-7.
Pełny tekst źródłaStreszczenie:
AbstractEnvironmentally friendly copper oxide nanoparticles (CuO NPs) were prepared with a green synthesis route without using hazardous chemicals. Hence, the extracts of mint leaves and orange peels were utilized as reducing agents to synthesize CuO NPs-1 and CuO NPs-2, respectively. The synthesized CuO NPs nanoparticles were characterized using scanning electron microscopy (SEM), Energy Dispersive X-ray Analysis (EDX), BET surface area, Ultraviolet–Visible spectroscopy (UV–Vis), and Fourier Transform Infrared Spectroscopy (FT-IR). Various parameters of batch experiments were considered for the removal of Pb(II), Ni(II), and Cd(II) using the CuO NPs such as nanosorbent dose, contact time, pH, and initial metal concentration. The maximum uptake capacity (qm) of both CuO NPs-1 and CuO NPs-2 followed the order of Pb(II) > Ni(II) > Cd(II). The optimum qm of CuO NPs were 88.80, 54.90, and 15.60 mg g−1 for Pb(II), Ni(II), and Cd(II), respectively and occurred at sorbent dose of 0.33 g L−1 and pH of 6. Furthermore, isotherm and kinetic models were applied to fit the experimental data. Freundlich models (R2 > 0.97) and pseudo-second-order model (R2 > 0.96) were fitted well to the experimental data and the equilibrium of metal adsorption occurred within 60 min.