Academic literature on the topic 'Volume-surface diameter of droplets'
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Journal articles on the topic "Volume-surface diameter of droplets"
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Trapuzzano, Matthew, Andrés Tejada-Martínez, Rasim Guldiken, and Nathan Crane. "Volume and Frequency-Independent Spreading of Droplets Driven by Ultrasonic Surface Vibration." Fluids 5, no. 1 (February 2, 2020): 18. http://dx.doi.org/10.3390/fluids5010018.
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Many industrial processes depend on the wetting of liquids on various surfaces. Understanding the wetting effects due to ultrasonic vibration could provide a means for changing the behavior of liquids on any surface. In previous studies, low-frequency surface vibrations have been used to alter wetting states of droplets by exciting droplet volume modes. While high-frequency (>20 kHz) surface vibration can also cause droplets to wet or spread on a surface, this effect is relatively uncharacterized. In this study, droplets of various liquids with volumes ranging from 2 to 70 µL were vibrated on hydrophobic-coated (FluoroSyl) glass substrates fixed to a piezoelectric transducer at varying amplitudes and at a range of frequencies between 21 and 42 kHz. The conditions for contact line motion were evaluated, and the change in droplet diameter under vibration was measured. Droplets of all tested liquids initially begin to spread out at a similar surface acceleration level. The results show that the increase in diameter is proportional to the maximum acceleration of the surface. Finally, liquid properties and surface roughness may also produce some secondary effects, but droplet volume and excitation frequency do not significantly change the droplet spreading behavior within the parameter range studied.
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Wang, Yiting, Lijuan Qian, Zhongli Chen, and Fang Zhou. "Coalescence of Binary Droplets in the Transformer Oil Based on Small Amounts of Polymer: Effects of Initial Droplet Diameter and Collision Parameter." Polymers 12, no. 9 (September 9, 2020): 2054. http://dx.doi.org/10.3390/polym12092054.
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In engineering applications, the coalescence of droplets in the oil phase dominates the efficiency of water-oil separation. To improve the efficiency of water-oil separation, many studies have been devoted to exploring the process of water droplets colliding in the oil phase. In this paper, the volume of fluid (VOF) method is employed to simulate the coalescence of water droplets in the transformer oil based on small amounts of polymer. The influences of the initial diameter and collision parameter of two equal droplets on droplet deformation and coalescence time are investigated. The time evolution curves of the dimensionless maximum deformation diameter of the droplets indicate that the larger the droplet diameter, the more obvious the deformation from central collisions. As the collision parameter increases, the contact area of the two droplets, as well as the kinetic energy that is converted into surface energy, decreases, resulting in an increase in droplet deformation. Furthermore, the effects of the initial droplet diameter and collision parameter on coalescence time are also investigated and discussed. The results reveal that as the initial droplet diameter and collision parameter increase, the droplet coalescence time increases.
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Huang, Xuefeng, Ling Sheng, Yibin Lu, and Shengji Li. "Atomization Characteristics of Hydrogen Peroxide Solutions in Electrostatic Field." Micromachines 13, no. 5 (May 13, 2022): 771. http://dx.doi.org/10.3390/mi13050771.
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Hydrogen peroxide (H2O2) can be considered as a sterilant or a green propellant. For a common use in industrial application, spray is an effective method to form fine H2O2 droplets. In this paper, electrostatic atomization based on the configuration of needle ring electrodes is proposed to produce H2O2 spray by minimizing its effective surface tension. The breakup performances of H2O2 ligaments can be improved by increasing the electric field intensity, reducing the nozzle size, and adjusting suitable volume flow rate. The smallest average diameter of breakup droplets for 35 wt. % concentration H2O2 solution reached 92.8 μm under optimum operation conditions. The H2O2 concentration significantly influenced the breakup performance owing to the concentration effect on comprehensive physical properties such as density, surface tension, viscosity, and permittivity. The average diameters of breakup droplets decreased with decreasing H2O2 concentration. At 8 wt. % concentration, the average breakup droplet diameter was reduced to 67.4 μm. Finally, electrostatic atomization mechanism of H2O2 solution was analyzed by calculating dimensionless parameters of Re, We, and Oh numbers with the combination of the operation conditions and physical properties for in-depth understanding the breakup behaviors. The calculation showed that the minimum average diameter of breakup droplets was obtained at 8 wt. % concentration at the investigated range of H2O2 concentration, which kept in agreement with the experimental results.
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Batalov, V. G., R. A. Stepanov, and A. U. Vasilev. "Quality estimation of the nozzle spray by measuring the brightness of the reflected light." Journal of Physics: Conference Series 2057, no. 1 (October 1, 2021): 012083. http://dx.doi.org/10.1088/1742-6596/2057/1/012083.
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Abstract This paper presents the results of the laboratory and numerical experiments performed to measure the sizes of transparent liquid droplets sprayed in air. The results of the laboratory experiments were mainly obtained using the Glare Point Technique (GPT) which gave information about the droplet size and the brightness of the light reflected by drops. The relationship between the brightness of the light reflected from the surface of droplets and their sizes was analyzed. Theoretically, the brightness of light scattered by a single spherical drop is proportional to the drop surface area and, accordingly, to the square of the drop diameter. It has been observed experimentally and verified numerically that the theoretical dependence obtained is relevant only for the brightest droplets because of nonuniform illumination. The results of the numerical experiments with a random sample of drops indicated the dependence of the total brightness of reflected light on the effective droplet size. It is shown that, for a fixed total volume, the total brightness of light reflected by drops is proportional to the droplet Sauter mean diameter.
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Clément, Sophie, Catherine Fauvelle, Emilie Branche, Vincent Kaddai, Stéphanie Conzelmann, Tujana Boldanova, Birke Bartosch, Kaori Minehira, and Francesco Negro. "Role of seipin in lipid droplet morphology and hepatitis C virus life cycle." Journal of General Virology 94, no. 10 (October 1, 2013): 2208–14. http://dx.doi.org/10.1099/vir.0.054593-0.
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Infectious hepatitis C virus (HCV) particle assembly starts at the surface of lipid droplets, cytoplasmic organelles responsible for neutral fat storage. We analysed the relationship between HCV and seipin, a protein involved in lipid droplet maturation. Although seipin overexpression did not affect the total mean volume occupied by lipid droplets nor the total triglyceride and cholesterol ester levels per cell, it caused an increase in the mean diameter of lipid droplets by 60 %, while decreasing their total number per cell. The latter two effects combined resulted in a 34 % reduction of the total outer surface area of lipid droplets per cell, with a proportional decrease in infectious viral particle production, probably due to a defect in particle assembly. These results suggest that the available outer surface of lipid droplets is a critical factor for HCV release, independent of the neutral lipid content of the cell.
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Li, Ze Fu, Lin Zhang, Xuan Luo, Xiao Jun Wang, and Yi Yang. "Simulation of Droplets Formation in Co-Flowing Microfluidic Channels." Applied Mechanics and Materials 513-517 (February 2014): 4180–84. http://dx.doi.org/10.4028/www.scientific.net/amm.513-517.4180.
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Emulsion droplets or multi-emulsion droplet formation was important for functional materials synthesizing by microfluidic. To obtain tunable monodisperse droplets with millimeter scale, the flow regime in co-flowing channels was divided by numerical simulation. A typical co-flowing model was created using finite volume method, and the VOF (volume of fluid) muti-phase model was selected. Then, droplets were produced by changing the velocity ratio under the dripping regime. Compared to the experimental value of droplet diameter, theoretical and numerical absolute error was below 60 % and 15 %, separately. Greet agreement of diameter changing tendency was found in simulation and experiment.
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Gao, Sihang, Fuqiang Chu, Xuan Zhang, and Xiaomin Wu. "Behavior of condensed droplets growth and jumping on superhydrophobic surface." E3S Web of Conferences 128 (2019): 07003. http://dx.doi.org/10.1051/e3sconf/201912807003.
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Droplets on the superhydrophobic surface can fall off the surface spontaneously, which greatly promote dropwise condensation. This study considers a continuous droplet condensation process including droplet growth and droplet jumping. A droplet growth model considered NCG is developed and droplet jumping is simulated using VOF (Volume Of Fluid) model. Al–based superhydrophobic surfaces are prepared using chemical deposition and etching method. The Al-based superhydrophobic surface has a contact angle of 157°±1° and a rolling angle of 2°±1°. An observation experiment is designed to observe droplet jumping on superhydrophobic surface using a high– speed camera system. The result of droplet growth model shows a good match with experimental data in mid-term of droplet growth. Fordroplet jumping, simulation and experiment results show that droplet jumping of different diameter hasa universality in a non–dimensional form. The jumping process can be divided into 3 stages and droplet vibration is observed.
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OLIVEIRA, RONE B. DE, ULISSES R. ANTUNIASSI, and MARCO A. GANDOLFO. "Spray adjuvant characteristics affecting agricultural spraying drift." Engenharia Agrícola 35, no. 1 (February 2015): 109–16. http://dx.doi.org/10.1590/1809-4430-eng.agric.v35n1p109-116/2015.
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This study defined the main adjuvant characteristics that may influence or help to understand drift formation process in the agricultural spraying. It was evaluated 33 aqueous solutions from combinations of various adjuvants and concentrations. Then, drifting was quantified by means of wind tunnel; and variables such as percentage of droplets smaller than 50 μm (V50), 100 μm (V100), diameter of mean volume (DMV), droplet diameter composing 10% of the sprayed volume (DV0.1), viscosity, density and surface tension. Assays were performed in triplicate, using Teejet XR8003 flat fan nozzles at 200 kPa (medium size droplets). Spray solutions were stained with Brilliant Blue Dye at 0.6% (m/ v). DMV, V100, viscosity cause most influence on drift hazardous. Adjuvant characteristics and respective methods of evaluation have applicability in drift risk by agricultural spray adjuvants.
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Yao, S. C., L. E. Hochreiter, and K. Y. Cai. "Dynamics of Droplets Impacting on Thin Heated Strips." Journal of Heat Transfer 110, no. 1 (February 1, 1988): 214–20. http://dx.doi.org/10.1115/1.3250454.
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Experiments were conducted with water droplets impacting on the edge of thin steel strips that were heated to beyond the Leidenfrost temperature. High-speed movies were taken and analyzed and showed that the shattered droplets were generally bimodal in size distribution. The volume ratio of these two size groups of generated droplets, the mean diameter of droplets, and the ejection angles and velocities of shattered droplets are shown as a function of incoming droplet Weber number, the ratio of incoming droplet diameter to strip thickness, and the offset of the droplet relative to the strip. The data are presented in nondimensional form and correlations are provided for the mean diameter of the shattered droplets. The theoretical limiting conditions of a droplet impacting normally to a large plate and cutting by a strip of zero thickness are analyzed. The present results are compared with those of the limiting conditions. The application to a nuclear reactor spacer grid behavior during two-phase dispersed flow is discussed.
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Egley, Grant H., James E. Hanks, and C. Douglas Boyette. "Invert Emulsion Droplet Size and Mycoherbicidal Activity ofColletotrichum truncatum." Weed Technology 7, no. 2 (June 1993): 417–24. http://dx.doi.org/10.1017/s0890037x00027822.
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When formulated and sprayed in an invert emulsion (IE), conidia of the mycoherbicide,Colletotrichum truncatum, controlled hemp sesbania in the absence of dew. To optimize hemp sesbania control, formulation droplet size influence upon the pathogen's germination and pathogenicity was investigated. Conidia germination in manually produced IE droplets decreased from 46% to 5% as droplet diameter decreased from 2700 to 900μm. Droplet size did not affect appressoria formation. On a per conidium basis, 900-μm droplets were more pathogenic to detached hemp sesbania leaves than were 2100-μm droplets. An air-assist spray system produced droplet spectra with volume median diameters of 421 and 104μm, respectively. The spectrum of smaller droplets covered the target better than did that of larger droplets. When applied to whole hemp sesbania plants in greenhouse trials, conidia in the smaller and larger droplet spectra gave 90 and 94% control, respectively. Sufficient conidia germinated in IE droplets of a variety of sizes to control hemp sesbania excellently.
Dissertations / Theses on the topic "Volume-surface diameter of droplets"
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Рачинський, Артур Юрійович. "Гідродинаміка і тепломасообмін в контактному утилізаторі теплоти газокрапельного типу." Thesis, КПІ ім. Ігоря Сікорського, 2017. https://ela.kpi.ua/handle/123456789/19313.
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Роботу присвячено експериментальним дослідженням, що направлені на підвищення ефективності роботи контактних тепломасообмінних апаратів шляхом збільшення міжфазної поверхні тепломасообміну при розпилені рідини відцентровими форсунками, впровадження яких приводить до суттєвої економії матеріальних та енергетичних ресурсів. Виконано комплексні експериментальні дослідження характеристик факелу розпилу рідини (густини зрошення, кута розкриття факела форсунки, середнього об’ємно-поверхневого діаметра крапель рідини). Встановлено вплив вхідних параметрів на відповідні характеристики та визначено площу поверхні крапель розпиленої рідини. Експериментально встановлено значення граничної температури нагріву води та її залежність від початкового паровмісту, при якій вода нагрівається до граничної температури в залежності від початкового паровмісту й витрати сухого повітря. Визначено параметричні границі ефективного використання відцентрової механічної форсунки без випаровування крапель нагрітої рідини. Експериментально досліджено інтенсивність тепло- і масоовіддачі в контактному апараті газокрапельного типу з відцентровою форсункою в умовах утилізації теплоти відхідних газів енергетичних агрегатів. Вперше отримано емпіричні залежності для розрахунку середніх коефіцієнтів тепловіддачі та масовіддачі, які відносяться до дійсної поверхні крапель розпиленої води. Встановлено особливості процесів переносу в газокрапельній системі та отримано узагальнювальні залежності для процесів тепло- і масовіддачі. На основі експериментальних досліджень характеристик розпилу та процесів тепломасообміну при конденсації пари з парогазової суміші на краплях розпиленої рідини розроблено методику розрахунку крапельного контактного утилізаційного апарату.Dissertation is devoted to experimental research, aimed at improving the efficiency of contact heat and mass transfer units by increasing the interfacial surface of heat and mass transfer during the liquid spraying by centrifugal nozzles, implementation of which results in significant savings of material and energy resources. Comprehensive experimental study of the characteristics of the liquid spraying torch (irrigation density, expansion angle of nozzle torch, the average volume-surface diameter of liquid droplets) was done. The influence of input parameters to the relevant properties was shown and surface area of the sprayed liquid droplets was defined. The limit temperature of water heating and its dependence on initial vapor content in which water is heated to the limit temperature depending on the initial vapor content and dry air output were experimentally set. The parametric borders of effective use of centrifugal mechanical nozzle without evaporation of heated liquid drops were defined. Intensity of heat and mass transfer in the contact gas-droplet unit with centrifugal nozzle in terms of heat utilization of energy units’ exhaust gases was experimentally researched. The empirical dependences for calculating the average heat transfer and mass transfer coefficients relating to the actual surface of the sprayed liquid droplets are obtained for the first time. The peculiarities of transfer processes in the gas-droplet system were determined and generalized dependence for heat and mass transfer were received. Based on experimental studies of spraying characteristics and heat and mass transfer processes at vapor condensation from vapor-gas mixture on the sprayed liquid droplets, the method of calculating the droplet contact utilization unit was developed.
Диссертация посвящена исследованиям, направленным на повышение эффективности работы контактных аппаратов путем увеличения межфазной поверхности теплообмена путем распыления жидкости, внедрение которых приводит к существенной экономии материальных и энергетических ресурсов. Работа содержит результаты экспериментальных исследований характеристик распыла и процессов тепломассоотдачи при конденсации пара из парогазовой смеси на каплях распыленной жидкости. Исследовано влияние температуры и давления воды на тонкость распыла (величину среднего объемно-поверхностного диаметра капель) для центробежной форсунки в параметрических условиях ее работы и применительно к условиям работы контактного утилизатора теплоты отходящих газов. На основании проведенных опытов получены новые зависимости величины среднего объемно-поверхностного диаметра капель для параметров распыливания жидкости с помощью центробежной форсунки в новом диапазоне изменения избыточного давления и температуры воды перед форсункой. В результате теоретического анализа движения капель жидкости в факеле распыления центробежной форсунки и использования экспериментальных данных по средним объемно-поверхностным диаметрам капель предложена методика определения действительной межфазной поверхности процессов тепломассообмена в контактных газожидкостных аппаратах капельного типа. Экспериментально определена зависимость граничной температуры нагрева воды в контактном аппарате газокапельного типа с центробежной форсункой применительно к условиям утилизации теплоты отходящих газов энергетических агрегатов. Исследования проведены в диапазоне избыточных давлений воды перед форсункой (0,2–0,6) МПа и объемной доли водяных паров парогазовой смеси на входе в аппарат от 0,02 до 0,45. Показано использование полученной зависимости для рас чета предельных значений параметров парогазового потока, ограничивающих область эффективной работы контактного аппарата с конденсацией пара и отсутствием режима испарения капель нагретой жидкости. Экспериментально определена интенсивность тепло- и массоотдачи в контактном аппарате газокапельного типа с центробежной форсункой в условиях утилизации теплоты отходящих газов энергетических агрегатов. Исследование проведены в диапазоне избыточного давления воды перед форсункой (0,2 - 0,6) МПа и объемной долей водяного пара парогазовой смеси на входе в аппарат от 0,08 до 0,35. По результатам экспериментальных исследований определены коэффициенты тепло- и массоотдачи, которые были отнесены к реальной поверхности капель. Полученные в работе результаты экспериментальных исследований коэффициентов тепло- и массоотдачи сравнивались с известными литературными данными для одиночной капли. Установлено, что интенсивность теплоотдачи для капель жидкости с парогазовым потоком выше, чем для одиночной капли, а для массоотдачи, ниже. Установлены особенности процессов переноса в газокапельной системе и получены обобщающие зависимости для процессов тепло- и массообмена для факела капель конуса распыла. В результате указанного комплекса работ предложена методика теплового расчета контактного газокапельного утилизатора теплоты низкотемпературных отходящих газов при распылении жидкости механической центробежной форсункой, которая учитывает реальные условия протекания процессов переноса в рассматриваемой двухфазной системе. Приведенная процедура теплового расчета утилизационной установки позволяет при заданных параметрах отходящих газов и воды на входе получить тип и количество распылителей для генерирования капель воды, выполнить компоновку в штатном коробе для отвода газов, рассчитать параметры теплоносителей на выходе с установки и определить ее теплопроизводительность.
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Рачинський, Артур Юрійович. "Гідродинаміка і тепломасообмін в контактному утилізаторі теплоти газокрапельного типу." Doctoral thesis, Київ, 2017. https://ela.kpi.ua/handle/123456789/19312.
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Роботу присвячено експериментальним дослідженням, що направлені на підвищення ефективності роботи контактних тепломасообмінних апаратів шляхом збільшення міжфазної поверхні тепломасообміну при розпилені рідини відцентровими форсунками, впровадження яких приводить до суттєвої економії матеріальних та енергетичних ресурсів. Виконано комплексні експериментальні дослідження характеристик факелу розпилу рідини (густини зрошення, кута розкриття факела форсунки, середнього об’ємно-поверхневого діаметра крапель рідини). Встановлено вплив вхідних параметрів на відповідні характеристики та визначено площу поверхні крапель розпиленої рідини. Експериментально встановлено значення граничної температури нагріву води та її залежність від початкового паровмісту, при якій вода нагрівається до граничної температури в залежності від початкового паровмісту й витрати сухого повітря. Визначено параметричні границі ефективного використання відцентрової механічної форсунки без випаровування крапель нагрітої рідини. Експериментально досліджено інтенсивність тепло- і масоовіддачі в контактному апараті газокрапельного типу з відцентровою форсункою в умовах утилізації теплоти відхідних газів енергетичних агрегатів. Вперше отримано емпіричні залежності для розрахунку середніх коефіцієнтів тепловіддачі та масовіддачі, які відносяться до дійсної поверхні крапель розпиленої води. Встановлено особливості процесів переносу в газокрапельній системі та отримано узагальнювальні залежності для процесів тепло- і масовіддачі. На основі експериментальних досліджень характеристик розпилу та процесів тепломасообміну при конденсації пари з парогазової суміші на краплях розпиленої рідини розроблено методику розрахунку крапельного контактного утилізаційного апарату.
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Khosravi, Mardkhe Maryam. "Facile Synthesis and Characterization of a Thermally Stable Silica-Doped Alumina with Tunable Surface Area, Porosity, and Acidity." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/3968.
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Mesoporous γ-Al2O3 is one of the most widely used catalyst supports for commercial catalytic applications. The performance of a catalyst strongly depends on the combination of textural, chemical and physical properties of the support. Pore size is essential since each catalytic system requires a unique pore size for optimal catalyst loading, diffusion and selectivity. In addition, high surface area and large pore volume usually result in higher catalyst loading, which increases the number of catalytic reaction sites and decreases reaction time. Therefore, determination of surface area and porosity of porous supports is critical for the successful design and optimization of a catalyst support. Moreover, it is important to produce supports with good thermal stability since pore collapsing due to sintering at high temperatures often results in catalyst deactivation. In addition, the ability to control the acidity of the catalyst enables us to design desirable acid sites to optimize product selectivity, activity, and stability in different catalytic applications. This dissertation presents a simple, one-pot, solvent-deficient method to synthesize thermally stable silica-doped alumina (SDA) without using templates. The XRD (X-ray diffraction), HTXRD (high temperature X-ray diffraction), SS NMR (solid state nuclear magnetic resonance), TEM (transmission electron microscopy), TGA(thermogravimetric analysis), and N2 adosorption techniques are used to characterize the structures of the synthesized SDAs and understand the origin of increased thermal stability. The obtained SDAs have a surface area of 160 m2/g, pore volume of 0.99 cm3/g, and a bimodal pore size distribution of 23 and 52 nm after calcination at 1100◦C. Compared to a commercial SDA, the surface area, pore volume, and pore diameter of synthesized SDAs are higher by 46%, 155%, and 94%, respectively. A split-plot fractional-factorial experimental design is also used to obtain a useful mathematical model for the control of textural properties of SDAs with a reduced cost and number of experiments. The proposed quantitative models can predict optimal conditions to produce SDAs with high surface areas greater than 250 m2/g, large pore volume greater than 1 cm3/g, and large (40-60 nm) or medium (16-19 nm) pore diameters. In my approach, I control acid sites formation by altering preparation variables in the synthesis method such as Si/Al ratio and calcination temperatures. The total acidity concentration (Brønsted and Lewis) of the synthesized SDAs are determined using ammonia temperatured program, pyridine fourier transform infrared spectroscopy (FTIR), and MAS NMR. The total acidity concentration is increased by introducing a higher mole ratio of Si to Al. In addition, the total acidity concentration is decreased by increasing calcination temperature while maintaining high surface area, large porosity, and thermal stability of γ-alumina support. I also present an optimized synthesis of various aluminum alkoxides (aluminum n-hexyloxide (AH), aluminum phenoxide (APh) and aluminum isopropoxide (AIP)) with high yields (90-95%). One mole of aluminum is reacted with excess alcohol in the presence of 0.1 mole % mercuric chloride catalyst. The synthesized aluminum alkoxides are used as starting materials to produce high surface area alumina catalyst supports. Aluminum alkoxides and nano aluminas are analyzed by 1H NMR, 13C NMR, 27Al NMR, gCOSY (2D nuclear magnetic resonance spectroscopy), IR (infrared spectroscopy), XRD, ICP (induced coupled plasma), and elemental analysis.
Books on the topic "Volume-surface diameter of droplets"
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van Hinsbergh, Victor W. M. Physiology of blood vessels. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198755777.003.0002.
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This chapter covers two major fields of the blood circulation: ‘distribution’ and ‘exchange’. After a short survey of the types of vessels, which form the circulation system together with the heart, the chapter describes how hydrostatic pressure derived from the heartbeat and vascular resistance determine the volume of blood that is locally delivered per time unit. The vascular resistance depends on the length of the vessel, blood viscosity, and, in particular, on the diameter of the vessel, as formulated in the Poiseuille-Hagen equation. Blood flow can be determined in vivo by different imaging modalities. A summary is provided of how smooth muscle cell contraction is regulated at the cellular level, and how neuronal, humoral, and paracrine factors affect smooth muscle contraction and thereby blood pressure and blood volume distribution among tissues. Subsequently the exchange of solutes and macromolecules over the capillary endothelium and the contribution of its surface layer, the glycocalyx, are discussed. After a description of the Starling equation for capillary exchange, new insights are summarized(in the so-called glycocalyx cleft model) that led to a new view on exchange along the capillary and on the contribution of oncotic pressure. Finally mechanisms are indicated in brief that play a role in keeping the blood volume constant, as a constant volume is a prerequisite for adequate functioning of the circulatory system.
Book chapters on the topic "Volume-surface diameter of droplets"
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Fountzoulas, Costas G. "Spinel Modeling Embedded with Small Diameter Surface Transparent Material Particles." In Dynamic Behavior of Materials, Volume 1, 189–95. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-4238-7_25.
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Privalov, Vadim E., Vladimir V. Dyachenko, Alina A. Kovalyova, and Valery G. Shemanin. "Laser System for the Average Volume-Surface Diameter of Aerosol Particles Measuring." In Springer Proceedings in Physics, 351–58. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-58868-7_40.
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Jjagwe, Aisha, Vincent Kakembo, and Barasa Bernard. "Land Use Cover Types and Forest Management Options for Carbon in Mabira Central Forest Reserve." In African Handbook of Climate Change Adaptation, 2733–54. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-45106-6_145.
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AbstractMabira Central Forest Reserve (CFR), one of the biggest forest reserves in Uganda, has increasingly undergone encroachments and deforestation. This chapter presents the implications of a range of forest management options for carbon stocks in the Mabira CFR. The effects of forest management options were reviewed by comparing above-ground biomass (AGB), carbon, and soil organic carbon (SOC) in three management zones. The chapter attempts to provide estimates of AGB and carbon stocks (t/ha) of forest (trees) and SOC using sampling techniques and allometric equations. AGB and carbon were obtained from a count of 143 trees, measuring parameters of diameter at breast height (DBH), crown diameter (CW), and height (H) with tree coordinates. It also makes use of the Velle (Estimation of standing stock of woody biomass in areas where little or no baseline data are available. A study based on field measurements in Uganda. Norges Landbrukshoegskole, Ås, 1995) allometric equations developed for Uganda to estimate AGB.The strict nature reserve management zone was noted to sink the highest volume of carbon of approximately 6,771,092.34 tonnes, as compared to the recreation zone (2,196,467.59 tonnes) and production zone (458,903.57 tonnes). A statistically significant relationship was identified between AGB and carbon. SOC varied with soil depth, with the soil surface of 0–10 cm depth registering the highest mean of 2.78% across all the management zones. Soil depth and land use/cover types also had a statistically significant effect on the percentage of SOC (P = 0.05). A statistically significant difference at the 95% significance level was also identified between the mean carbon stocks from one level of management zones to another. Recommendations include: demarcating forest boundaries to minimize encroachment, enforcement of forestry policy for sustainable development, promote reforestation, and increase human resources for efficient monitoring of the forest compartments.
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Johnston, Keith P., and C. T. Lee. "Interfacial Phenomena with Carbon Dioxide Soluble Surfactants." In Green Chemistry Using Liquid and Supercritical Carbon Dioxide. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780195154832.003.0013.
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A fundamental understanding of colloid and interface science for surfactant design in CO2-based systems is emerging on the basis of studies of interfacial tension and surfactant adsorption (da Rocha et al., 1999) along with complementary studies of colloid structure (Chillura-Martino et al., 1996; Meredith and Johnston, 1999; Wignall, 1999) and stability (Meredith and Johnston, 1999; O’Neill, 1997; Yates et al., 1997). The interfacial tension, γ, between a supercritical fluid (SCF) phase and a hydrophilic or lipophilic liquid or solid, along with surfactant adsorption, play a key role in a variety of processes including nucleation, coalescense and growth of dispersed phases, formation of microemulsions and emulsions (Johnston et al., 1999), particle and fiber formation, atomization, foaming (Goel and Beckman, 1995), wetting, adhesion, lubrication, and the morphology of blends and composites (Watkins et al., 1999). The first generation of research involving surfactants in SCFs addressed water/oil (w/o) microemulsions (Fulton and Smith, 1988; Johnston et al., 1989) and polymer latexes (Everett and Stageman, 1978) in ethane and propane (Bartscherer et al., 1995; Fulton, 1999; McFann and Johnston, 1999). This work provided a foundation for studies in CO2, which has modestly weaker van der Waals forces (polarizability per volume) than ethane. Consequently, polymers with low cohesive energy densities and thus low surface tensions are the most soluble in CO2: for example, fluoroacrylates (DeSimone et al., 1992), fluorocarbons, fluoroethers (Singley et al., 1997), siloxanes, and to a lesser extent propylene oxide. Since CO2 is nonpolar (unlike water) and has weak van der Waals forces (unlike lipophilic phases), it may be considered to be a third type of condensed phase. Surfactants with the above types of “CO2-philic” segments and a “CO2-phobic” segment have been used to form microemulsions (Harrison et al., 1994; Johnston et al., 1996), emulsions (da Rocha et al., 1999; Jacobson et al., 1999a; Lee et al., 1999b), and organic polymer latexes (DeSimone et al., 1994) in CO2. Microemulsion droplets are typically 2–10 nm in diameter, making them optically transparent and thermodynamically stable, whereas kinetically stable emulsion droplets and latexes in the range of 200 nm to 10 mm are opaque and thermodynamically unstable.
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"Droplets: Shape, Surface and Volume." In The Physics of Microdroplets, 83–103. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118401323.ch3.
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Zeytunluoglu, Ali, and Idris Arslan. "Current Perspectives on Nanoemulsions in Targeted Drug Delivery." In Handbook of Research on Nanoemulsion Applications in Agriculture, Food, Health, and Biomedical Sciences, 118–40. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-7998-8378-4.ch006.
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Nanoemulsions are an isotropical mixture of oil, surfactant, and water with droplet diameter approximately in the range of 10-100 nm. They are being exponentially used for drug delivery systems for the influential administration of therapeutical agents because of their potential advantages over other approaches. Nanoemulsions can be used to design delivery systems that have increased drug loading, enhanced drug solubility, increased bioavailability, controlled drug release, and enhanced protection against chemical or enzymatic degradation. Moreover, nanoemulsions have better thermodynamical stability to flocculation, sedimentation, and creaming than conventional emulsions. Their small droplet dimensions and large droplet surface area positively influence drug transport and delivery, along with allowing targeting to specific sites. This chapter focuses on recent applications of nanoemulsions in the area of drug delivery.
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White, Robert E. "The Makeup of Soil." In Soils for Fine Wines. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195141023.003.0004.
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Minerals and organic matter comprise the solid phase of the soil. The geological origin of the soil minerals, and the input of organic matter from plants and animals, are briefly discussed in section 1.2.1. A basic knowledge of the composition and properties of these materials is fundamental to understanding how a soil influences the growth of grapevines. A striking feature of soil is the size range of the mineral matter, which varies from boulders (>600 mm diameter), to stones and gravel (600 to >2 mm diameter), to particles (<2 mm diameter)—the fine earth fraction. The fine earth fraction is the most important because of the type of minerals present and their large surface areas. The ratio of surface area to volume defines the specific surface area of a particle. The smaller the size of an object, the larger is the ratio of its surface area to volume. This can be demonstrated by considering spherical particles of radius 0.1 mm, 0.01 mm, and 0.001 mm (1 micrometer or micron, μm). The specific surface areas of these particles are 30, 300, and 3000 mm2/mm3, respectively. In practice, the specific surface area is measured as the surface area per unit mass, which implies a constant particle density (usually taken as 2.65 Mg/m3). A large specific surface area means that more molecules can be adsorbed on the surface. Representative values for the specific surface areas of sand, silt, and clay-size minerals are given in table 2.1. Note the large range in specific surface area, even for the clay minerals, from as little as 5 m2/g for kaolinite to 750 m2/g for Na-montmorillonite. Because specific surface areas are important, we need to know the size distribution of particles in the fine earth fraction. This is expressed as the soil’s texture. The types of minerals that make up the individual size fractions are also important because they too influence the reactivity of the surfaces. Both these topics are discussed here. All soils show a continuous distribution of particle sizes, called a frequency distribution. This distribution relates the number (or mass) of particles of a given size to their actual size, measured by the diameter of an equivalent sphere.
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Bayly, Brian. "Change of Shape and Change of Volume." In Chemical Change in Deforming Materials. Oxford University Press, 1993. http://dx.doi.org/10.1093/oso/9780195067644.003.0012.
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In earlier chapters we first defined a material's chemical potential, and then went on to enquire how the material responds. And similarly with a state of nonhydrostatic stress: having reviewed what it is, we consider how a material might respond. For the sake of simplicity, we imagine an extensive sample, such as a cubic meter, and suppose that the stress state is the same in every cubic centimeter; that is to say, there are no gradients in stress from point to point. Thus we do not enquire yet how a material responds to a spatial stress gradient; that comes later. We first enquire how it responds to a homogeneous but nonhydrostatic stress. Inside the material, close to the point of interest, we define a small length l by means of the material particles at its two ends. If, at a later moment, we find the distance between the particles to be l — δl, then we envisage the limit of the ratio δl/l as l goes to zero, give the limit the symbol ε, and name it the linear strain at the point of interest in the direction of l, positive when δl is positive, i.e., for a shortening and negative for an elongation. Another mental operation that can be performed in the neighborhood of the point of interest is to define a small sphere by means of the material particles that form its surface. At a later moment the particles will form the surface of an ellipsoid. (For a large sphere and an inhomogeneous situation, the new shape can be something more complicated; but as the imagined original sphere approaches zero diameter, the shape of its deformed counter-part can only approach an ellipsoid). The axes of the ellipsoid are principal directions of strain, and the magnitudes of the strains along them are named ε1, ε2, and ε3, with ε1 the largest. In an isotropic material, the principal axes of stress and strain coincide, with ε1 lying along the direction of σ1 and correspondingly; see Figure 7.la. As with stresses, the three values of ε themselves define an ellipsoid if they are all positive—see Figure 7.1b.
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Carter, Jonathan L., and J. Clarke Stevens. "Somatosensory Evoked Potentials." In Clinical Neurophysiology, 257–80. Oxford University Press, 2009. http://dx.doi.org/10.1093/med/9780195385113.003.0018.
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SEPs recorded with surface electrodes represent volume-conducted activity arising from myelinated peripheral and central axons, synapses in central gray matter, and changes in the size and shape of the volume conductor. They provide an objective measure of function in large-diameter myelinated sensory afferents peripherally and in proprioceptive pathways centrally. Changes in amplitude and latency can be used to localize lesions in the nervous system, to identify objectively abnormalities in patients with few sensory manifestations or none at all, and to monitor function over time.
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Jee Kanu, Nand, Eva Gupta, Venkateshwara Sutar, Gyanendra Kumar Singh, and Umesh Kumar Vates. "An Insight into Biofunctional Curcumin/Gelatin Nanofibers." In Nanofibers - Synthesis, Properties and Applications. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97113.
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Electrospinning (ESPNG) was used to synthesize ultrathin (UT) and uniform nanofibers (from 5 nm to a few hundred nanometers) of various materials which have biomedical applications (BAs) such as dressing of wounds, drug discharge, and so on and so forth. In the first half of the report, there is an audit on the nanofibers having low diameter so that it could have larger surface area to volume proportion, likewise with that it would have sufficient porosity and improved mechanical properties required for wound healing. Nanofibrous mats (NMs) with high biocompatibility could be utilized during healing of wounds by sustained release of curcumin (Cc) and oxygen. The ESPNG was understood through in-depth numerical investigation in the present report. Furthermore, the process parameters (PMs) were reviewed in depth for their contributions in synthesizing UT - Curcumin/Gelatin (Cc/G) nanofibers (NFs) of optimum diameter. The aim of the discussion was to demonstrate that simply optimizing biofunctional (BF) - Cc/G NFs might not be enough to satisfy experts until they are also given access details about the complete ESPNG method (mathematical mechanism) to improve hold over the synthesis of NMs (suitable for BAs) for the release profile of Cc throughout critical periods of healing process.
Conference papers on the topic "Volume-surface diameter of droplets"
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Raghavan, Vasudevan, Daniel N. Pope, and George Gogos. "Combined Non-Luminous Flame Radiation and Surface Tension Effects During Methanol Droplet Combustion." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43425.
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The effect of non-luminous thermal radiation on suspended (constant relative velocity) methanol droplet combustion in a low temperature (300 K) and low pressure (1 atm) environment is discussed in detail. Numerical results are obtained using a predictive, transient, two-phase, axisymmetric numerical model that includes surface tension effects. Radiation is modeled using the optically thin approximation with the product species CO2 and H2O as the radiating species. Results for combustion in a quiescent atmosphere (initial Reynolds number 0.01) and initial droplet diameters in the range of 0.43 mm to 3 mm are presented. The results show that the effect of flame radiation is negligible when the initial droplet diameter is less than approximately 1 mm and becomes increasingly important for droplets with initial diameters greater than approximately 1 mm, as reported in previous literature. The average evaporation constant decreases with the initial droplet diameter. Both radiation and surface tension have a significant effect on the predicted extinction diameters of initially larger droplets. The extinction diameter presents a non-linear variation with the initial droplet diameter for initially larger droplets and agreement with experiments is good.
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Raghavan, Vasudevan, Daniel N. Pope, and George Gogos. "The Role of Surface Tension Effects During Methanol Droplet Combustion." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13801.
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A numerical investigation of methanol droplet combustion in a zero-gravity and low-pressure convective environment is presented. Simulations have been carried out using a predictive, transient and axisymmetric model, which includes droplet heating, liquid-phase circulation and water absorption. First, a suspended droplet (constant relative velocity) burning in an ambient of air at 300K is considered. A nearly quiescent environment (initial Reynolds number Re0=0.01) is used to impose a weak gas-phase convective flow, introducing a deviation from spherical symmetry. The resulting weak liquid-phase circulation is greatly enhanced due to surface tension effects, which create a complex, time-varying, multicellular flow pattern within the liquid droplet. The complex flow pattern, which, in the presence of surface tension, results in nearly perfect mixing, causes increased water absorption within the droplet, leading to larger extinction diameters. Surface tension effects are shown to be dominant in causing water absorption, even at initial Reynolds numbers as high as 5. Results for combustion in a nearly quiescent environment (Re0=0.01) with varying initial droplet diameters, (d0 = 0.16 to 1.72 mm), show that predictions of droplet extinction diameters, although they are still below the experimental data, do improve substantially when surface tension effects are included. Next, results for suspended droplets and for moving droplets burning in an ambient of air at 1200K, for a range of initial Reynolds numbers that are of interest in spray combustion (Re0=1-100) are presented. It is shown that, for moving droplets, due to the presence of an envelope flame at some stage during the droplet lifetime, surface tension is important over the entire range of Re0 considered; the extinction diameter decreases with increasing Re0. Extinction is not observed for a moving droplet when surface tension effects are neglected. For suspended droplets, when transition or envelope flame is present, which corresponds to Re0 less than approximately 15, surface tension is important; when an envelope flame is present (Re0 less than approximately 10), the extinction diameter increases with Re0. The variation of droplet lifetime with Re0 is much stronger for suspended droplets than for moving droplets. Depending on the Reynolds number, results on methanol droplet lifetimes and extinction diameters measured through suspended droplet experiments may not be applicable to moving droplets.
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Li, Jianxin, Huang Zhang, Yuzheng Li, Qianfeng Liu, and Hanliang Bo. "A Piezoelectric Droplet Generating Device for Experiment in Successive Droplets Impacting Onto Solid Surface." In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-81475.
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The outcomes of successive droplets impacting onto solid surface of the steam separator in a nuclear power system’s steam generator has a strong effect on the separating efficiency. Due to amounts of influencing factors, experimental research is an important method to study the phenomena of droplet-wall collision. However, because it is hard to generator continuous droplets with controllable uniform size and frequency, experimental studies about successive droplets impacting on solid surface are relative limited. In this study, a novel drop-on-demand (DOD) droplet generator is designed and fabricated based on piezoelectric ceramics, in which successive droplets with a uniform diameter can be generated. Firstly, the structure design of the DOD droplet generator, the setup of the control system and working principle are described in detail in this paper. Then the droplet generating performance of the device under different signal frequency fs, signal amplitude U, duty ratio Dr, and nozzle diameter Dn are investigated experimentally using a high-speed camera at 4000 fps. Finally, the influence of the signal frequency fs, voltage U, duty ratio Dr and nozzle diameter Dn on the diameter of droplet Dd is discussed. A test of successive droplets generated by the device impacting on an aluminum plate is conducted.
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Nago, Kohei, Yasuo Koizumi, Akihiro Uchibori, and Hiroyuki Ohshima. "Visualization of Entrainment and Surface Behavior of High Speed Air Jet Blowing Out From a Hole to Stagnant Water." In 2012 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icone20-power2012-55068.
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A two dimensional air jet was blown out from a nozzle into water in a thin vessel. The behavior of the interface between water and the air jet and also the air jet were recorded with a high speed video camera. Filament-like ears and wisps pulled-out from the wavy water surface were noticed in the recorded photos. Droplets are formed from these. Droplet diameters were obtained from the recorded photos. As the air velocity increased, the number of droplets created by the air jet increased lineally and the smaller droplets increased. The correlation for the droplet diameter distribution developed for the annular dispersed two-phase flow in a pipe predicted well the present results. The correlations for the droplet diameter developed for the annular dispersed two-phase flow in a pipe and for the jet blowing out from the stagnant water pool considerably underpredict the experimental results.
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Mahapatra, Sanjay, and Jeffrey K. Gilstrap. "Gas Turbine Inlet Air Cooling: Determination of Parameters to Evaluate Fogging Nozzle’s Atomizing Performance." In International Joint Power Generation Conference collocated with TurboExpo 2003. ASMEDC, 2003. http://dx.doi.org/10.1115/ijpgc2003-40124.
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Gas turbine inlet air-cooling using a fogging system is accomplished by using an array of high-pressure nozzles that inject micron-sized droplets in air stream. These droplets evaporate and diffuse in the air stream resulting in cooling and humidification of air. The cooled and moist inlet air increases net turbine power output, improves heat rate and reduces Nitrogen Oxides formation (NOx). The evaporation and mass diffusion of these droplets are influenced, among other factors, by its surface area to volume ratio. Large surface area facilitates drop interfacial heat transfer and smaller volume or weight aids higher droplet residence times. A fogging nozzle’s atomizing performance can be evaluated from its spray properties that include a mean drop size, droplet distribution, numerical droplet density, spray cone angle, and spray penetration. The spray industry adopts various definitions of mean drop size that suits its application and objective. Mean drop sizes or more commonly droplet diameters used in the gas turbine inlet air fogging industry are 90% cumulative volume frequency, Dv0.90 and the Sauter Mean Diameter, D32. Two sprays having identical mean or representative diameter are not necessarily similar in performance. Further, a spray from nozzle ‘A’ having a Dv0.90 less than another nozzle ‘B’ does not necessarily imply that ‘A’ is superior to ‘B’. This paper explains why the use of one or both of the above characteristic diameters does not effectively reflect a fog nozzle’ atomizing performance. This paper also analyzes various characteristic diameters and their relevance to evaporative cooling using fog nozzles. In fogging applications, the smallest and/or the largest sized drops in a spray will have significant impact on performance and neither Dv0.90 nor D32 can independently provide this information. Therefore, at least one other parameter such as the droplet distribution must be known in order to qualitatively define a spray from a fogging nozzle. This paper also determines these parameters such as the Relative Span Factor and Dispersion Boundary Factor and analyzes their importance to fogging performance.
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Li, Lanlan, Shiqiang Liang, Dawei Tang, and Liang Chen. "Visualization Study of Dropwise Condensation on a Super-Hydrophobic Surface." In ASME 2013 11th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icnmm2013-73046.
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Compared with conventional filmwise condensation, dropwise condensation has the advantage of high heat transfer coefficient when properly enhanced. To better understand the inherent mechanism of this outstanding performance and optimize the structure of the condensation surface, this paper focuses on the visualization experiments of dropwise condensation on a superhydrophobic surface to study the dynamic behaviors of droplet nucleation and growth. The surface is fabricated by chemically growing an n-octadecanethiol self-assembled monolayer coating with microscopic roughness on a copper surface. Some characteristics of interest such as the droplet nucleation, the droplet diameter, the number and the path of the droplets are obtained using image processing software. The experimental results indicate that the nucleation sites of the droplets are fixed, which in turn verifies the droplet nucleation theory. In addition, the nucleation of the small droplets together with the coalescence of the existing droplets contributes significantly to the variation of the number of the droplets.
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Schuler, Julia, Laura Maria Neuendorf, Kai Petersen, and Norbert Kockmann. "3D Investigation of Droplet Generation in a Miniaturized Coflowing Device Using Micro-Computed Tomography." In ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icnmm2020-1061.
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Abstract For many applications, such as liquid-liquid or gas-liquid reactions, the generation of monodisperse droplets is of major interest. Therefore, knowledge about the physics of droplet formation is essential and the subject of numerous studies. Droplet formation is usually investigated using optical cameras, which makes optical accessibility necessary. Furthermore, properties defining droplet evolution is obtained from 2D images. In this work, we present a methodology for the 3D investigation of droplet formation in the laminar regime using micro-computed tomography. A special imaging concept and image processing, incorporating the use of a convolutional neural network, is presented. Water droplets are injected into a continuous polydimethylsiloxane stream in a coflowing configuration using a cannula with an inner diameter di = 800 μm and an outer diameter do = 1050 μm that is centered in a thin polymer tube with an inner diameter di = 1600 μm. Volume flow rates of polydimethylsiloxane and water are varied between 0.2 and 0.3 mL min−1. Furthermore, the influence of cannula positioning on droplet formation is investigated. Different quantitative 3D properties are extracted from the CT scans, such as droplet volume and surface of the interface. Thereby, different stages of droplet formation can be identified and the physical understanding of droplet formation is improved.
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Abushamleh, Mohammed, and Ning Zhang. "CFD Simulation of COVID Aerosol Dispersion in Indoor Environments." In ASME 2021 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/fedsm2021-65877.
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Abstract Computational Fluid Dynamics simulations for the droplet’s dispersion generated by a cough in an indoor background, droplets trajectory, and evaporation time are predicted to be related to the droplet’s diameter and relative humidity. In general, medium-size droplets have higher axial penetration potential, and large droplets tend to settle on the ground due to gravity. Also, larger droplets take a longer time to evaporate. Smaller droplets tend to be suspended in the flow field with small penetration potential and tend to fade faster; smaller droplets < 20 μm evaporate completely before the simulation time reaches 0.75 sec. To study the effect of Relative Humidity (RH) on the evaporation rate, in particular, the present study offers three simulations, all with the same standard room conditions, only differ in relative humidity s 40%, 60%, and 90%. Another source of variability is the cough-expired volume. This study adopts existent experimental work to establish two cough flow rate profiles. The Lagrangian discrete phase model is adopted along with the species model to track and investigate the cough droplet dispersion and evaporation.
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Blake, Joshua D., David S. Thompson, Dominik M. Raps, Tobias Strobl, and Elmar Bonaccurso. "Effects of Surface Characteristics and Droplet Diameter on the Freezing of Supercooled Water Droplets Impacting a Cooled Substrate." In 6th AIAA Atmospheric and Space Environments Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2014. http://dx.doi.org/10.2514/6.2014-2328.
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Shen, Jian, James Liburdy, Deborah Pence, and Vinod Narayanan. "Single Droplet Impingment: Effect of Nanoparticles." In ASME 2008 Fluids Engineering Division Summer Meeting collocated with the Heat Transfer, Energy Sustainability, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/fedsm2008-55192.
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This study focuses on the dynamics of water and nanofluids droplet surface impingement. Droplets are generated by a piezoelectric driven droplet generator. A high-speed-high-resolution camera is used to record droplets impacting on a smooth heated silicon surface. Droplet impact velocity, spreading diameter, spreading height and dynamic contact angle are measured by image processing. Results of water and nanofluids are compared to determine effects of nanoparticles on spreading dynamics. It is concluded that the nanofluids result in larger spreading rates, larger spreading diameters and an increase in early stage dynamic contact angle.
Reports on the topic "Volume-surface diameter of droplets"
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Dagata, John A., Natalia Farkas, and John A. Kramer. Method for Measuring the Volume of Nominally 100 μm Diameter Spherical Water-in-Oil Emulsion Droplets. National Institute of Standards and Technology, February 2016. http://dx.doi.org/10.6028/nist.sp.260-184.
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Dasberg, Shmuel, Jan W. Hopmans, Larry J. Schwankl, and Dani Or. Drip Irrigation Management by TDR Monitoring of Soil Water and Solute Distribution. United States Department of Agriculture, August 1993. http://dx.doi.org/10.32747/1993.7568095.bard.
Full textAbstract:
Drip irrigation has the potential of high water use efficiency, but actual water measurement is difficult because of the limited wetted volume. Two long-term experiments in orchards in Israel and in California and several field crop studies supported by this project have demonstrated the feasibility of precise monitoring of soil water distribution for drip irrigation in spite of the limited soil wetting. Time Domain Reflectometry (TDR) enables in situ measurement of soil water content of well defined small volumes. Several approaches were tried in monitoring the soil water balance in the field during drip irrigation. These also facilitated the estimation of water uptake: 1. The use of multilevel moisture probe TDR system. This approach proved to be of limited value because of the extremely small diameter of measurement. 2. The placement of 20 cm long TDR probes at predetermined distances from the drippers in citrus orchards. 3. Heavy instrumentation with neutron scattering access tubes and tensiometers of a single drip irrigated almond tree. 4. High resolution spatial and temporal measurements (0.1m x 0.1m grid) of water content by TDR in corn irrigated by surface and subsurface drip. The latter approach was accompanied by parametric modelling of water uptake intensity patterns by corn roots and superimposed with analytical solutions for water flow from point and line sources. All this lead to general and physically based suggestions for the placement of soil water sensors for scheduling drip irrigation.