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Статті в журналах з теми "Washburn model"
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Chang, Sooyoung, Jaedeok Seo, Seokbin Hong, Duck-Gyu Lee, and Wonjung Kim. "Dynamics of liquid imbibition through paper with intra-fibre pores." Journal of Fluid Mechanics 845 (April 20, 2018): 36–50. http://dx.doi.org/10.1017/jfm.2018.235.
Повний текст джерелаАнотація:
We present a combined experimental and theoretical investigation of the dynamics of liquid imbibition through paper. The Washburn equation is widely used to describe the dynamics of capillary flow through paper, but this classical model has limited accuracy, which often makes it difficult to use in developing analytic systems such as paper-based microfluidic devices. We here report that the internal cavity of the cellulose fibres composing paper is significantly responsible for the limited accuracy of the Washburn equation. Our experiments demonstrated that liquid can be absorbed in the internal cavity of the cellulose fibres as well as in the inter-fibre pores formed by the fibre network. We developed a mathematical model for liquid imbibition by considering the flow through the intra-fibre pores based on experimental measurements of the intra-structure of cellulose fibres. The model markedly improves the prediction of the liquid absorption length, compared with the results of the Washburn equation, thus revealing the physics behind the limits of the Washburn equation. This study suggests that the accurate description of capillary imbibition through paper require parameters characterizing the internal pores of the cellulose fibres comprising the paper. Our results not only provide a new insight into porous media flows with different sized pores, but also provide a theoretical background for flow control in paper-based microfluidic systems.
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Villagrán Zaccardi, Yury, Natalia Alderete, and Nele De Belie. "Lucas-Washburn vs Richards equation for the modelling of water absorption in cementitious materials." MATEC Web of Conferences 199 (2018): 02019. http://dx.doi.org/10.1051/matecconf/201819902019.
Повний текст джерелаАнотація:
The Lucas-Washburn equation is still being applied by a significant number of researchers for the modelling of water absorption in cementitious materials. A modern approach considers the extended Darcy’s law leading to the Richards equation instead. Three main assumptions are implied by the application of the Lucas-Washburn equation: the flow occurs in one direction only, the material is separated into one fully wet and one fully dry region, and pores are modelled as an assembly of parallel tubes of a particular radius. Its application to analyse experimental results allows defining these three assumptions as mere simplifications. Therefore, all the parameters comprised in the Lucas-Washburn model are apparent. Consequently, a very limited description of the transport properties of the material can be achieved. For many engineering purposes this would not be an issue, but for an intrinsic description of the material a more realistic model is required. This paper discusses the limitations of the Lucas-Washburn equation, and the advantages of the Richards equation regarding the modelling of water absorption in cementitious materials. The comparative analysis reveals the versatility of the Richards equation, with an approach that considers the material as a continuum and describes it through measurable parameters.
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Wang, Pan, Qingen Zhang, Muhan Wang, Bing Yin, Dongshuai Hou, and Yue Zhang. "Atomistic insights into cesium chloride solution transport through the ultra-confined calcium–silicate–hydrate channel." Physical Chemistry Chemical Physics 21, no. 22 (2019): 11892–902. http://dx.doi.org/10.1039/c8cp07676f.
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Cao, Bing-Yang, Min Yang, and Guo-Jie Hu. "Capillary filling dynamics of polymer melts in nanopores: experiments and rheological modelling." RSC Advances 6, no. 9 (2016): 7553–59. http://dx.doi.org/10.1039/c5ra24991k.
Повний текст джерелаАнотація:
The spontaneous capillarity-driven flow behaviors of PE melts through AAO nanopores suggest that the zero-shear-rate viscosity of the PE melts decreases, which can be predicted by a modified Lucas–Washburn law considering the polymer rheological model.
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Zhang, Xiao Dan, Jun Hao Qian, and Jun Wei Jia. "Ink Penetration Model Research Based on Ink Permeability." Applied Mechanics and Materials 731 (January 2015): 462–65. http://dx.doi.org/10.4028/www.scientific.net/amm.731.462.
Повний текст джерелаАнотація:
This article analyzes the mechanism of interaction between the ink and paper. The Washburn equation just based on static penetration, while in contact with the ink and paper, freedom infiltration process is a dynamic process. So it is further derived based on a model of the dynamic ink permeability of dynamic contact angle, and mathematical analyzes some of the important parameters of the dynamic model so that can strive a more accurate description of the state of penetration of ink into the paper, thereby theoretically predict the quality control of printed matter.
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Gorthi, Srinivas R., Sanjaya Kumar Meher, Gautam Biswas, and Pranab Kumar Mondal. "Capillary imbibition of non-Newtonian fluids in a microfluidic channel: analysis and experiments." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 476, no. 2242 (October 2020): 20200496. http://dx.doi.org/10.1098/rspa.2020.0496.
Повний текст джерелаАнотація:
We have presented an experimental analysis on the investigations of capillary filling dynamics of inelastic non-Newtonian fluids in the regime of surface tension dominated flows. We use the Ostwald–de Waele power-law model to describe the rheology of the non-Newtonian fluids. Our analysis primarily focuses on the experimental observations and revisits the theoretical understanding of the capillary dynamics from the perspective of filling kinematics at the interfacial scale. Notably, theoretical predictions of the filling length into the capillary largely endorse our experimental results. We study the effects of the shear-thinning nature of the fluid on the underlying filling phenomenon in the capillary-driven regime through a quantitative analysis. We further show that the dynamics of contact line motion in this regime plays an essential role in advancing the fluid front in the capillary. Our experimental results on the filling in a horizontal capillary re-establish the applicability of the Washburn analysis in predicting the filling characteristics of non-Newtonian fluids in a vertical capillary during early stage of filling (Digilov 2008 Langmuir 24 , 13 663–13 667 ( doi:10.1021/la801807j )). Finally, through a scaling analysis, we suggest that the late stage of filling by the shear-thinning fluids closely follows the variation x ~ t . Such a regime can be called the modified Washburn regime (Washburn 1921 Phys. Rev. 17 , 273–283 ( doi:10.1103/PhysRev.17.273 )).
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Qu, Zhen Cai, Guang Xue Chen, Bao Lin Tang, and Shuang Shuang Wen. "Study on Model of Dot Gain in Ink-Jet Printing." Advanced Materials Research 236-238 (May 2011): 1405–9. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.1405.
Повний текст джерелаАнотація:
Ink-jet printing is a non-contact printing, drops are jetted on the substrates to form images through the nozzles at a certain speed. Dot is the smallest unit in printing; the qualities of printing are seriously affected by dot gain. Ink spreading and penetration are discussed in this paper, influences on dot gain in ink-jet printing are studied, the original Young's equation and Washburn formula are theoretically amended, more scientific and rational models and formulas are obtained in the actual process of ink-jet printing, which offers reference standard and theoretical basis to improve the quality of ink-jet printing.
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Peterson, Rorik A. "Assessing the role of differential frost heave in the origin of non-sorted circles." Quaternary Research 75, no. 2 (March 2011): 325–33. http://dx.doi.org/10.1016/j.yqres.2010.08.003.
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AbstractA. L. Washburn famously proposed and reviewed 19 hypotheses for the origin of patterned ground in periglacial environments over 50 years ago (Washburn, 1956). Of these 19 mechanisms, only a few have been analyzed starting from a fundamental description of the physics to assess their potential contribution to the initiation of patterned ground. Here, differential frost heave (DFH) is investigated as the origin of non-sorted circles in periglacial landscapes. Model results indicating that DFH can spontaneously lead to patterned ground are compared to measurements of patterned ground in the Canadian Arctic Archipelago. The characteristic size of the predicted emerging pattern depends strongly on the maximum depth of freezing but is only weakly dependent on the soil composition. The predicted emerging patterns may also be dramatically different in size with a small change in active layer when a relatively thin (~ 10 cm) insulating snow covers the ground during freezing. The model predicted trends agree with field observations of pattern size and active layer depth at two distinct sites. Although two data points cannot conclusively indicate a trend, this correlation gives support for the possibility of determining some subsurface properties using remote sensing images of surface patterned ground.
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Samayoa, Didier, Liliana Álvarez Romero, Lilian Aurora Ochoa Ontiveros, Lucero Priscila Damian Adame, Ehcatl Victoria-Tobon, and Gabriel Romero Paredes. "Fractal imbibition in Koch's curve-like capillar tubes." Revista Mexicana de Física 64, no. 3 (April 30, 2018): 291. http://dx.doi.org/10.31349/revmexfis.64.291.
Повний текст джерелаАнотація:
Fractal geometry eects in capillary imbibition process are studied.Capillary rise analysis in Koch's curve-like tubes were be carried out withiterations i = 0; 1; 2; 3; 4; 5. The behaviour was characterized in function oftime, fractal geometry and height of capillary rise. An geometrical relationshipfor fractal dimension of ow tortuosity (dr) in porous media is obtained.The analytical model of Lucas-Washburn-Cai to describe the capillary rise byspontaneus imbibition in tubes with deterministic fractal geometry is adjusted.The equilibrium height time as function of fractal dimension of ow tortuosity incapillary tubes with tortuous path is also derived.
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Cai, Shaobin, Li Zhang, Lixin Kang, Yongfei Yang, Wenlong Jing, Lei Zhang, Chao Xu, Hai Sun, and Mozhdeh Sajjadi. "Spontaneous Imbibition in a Fractal Network Model with Different Wettabilities." Water 13, no. 17 (August 29, 2021): 2370. http://dx.doi.org/10.3390/w13172370.
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In this work, we derived a mathematical model for spontaneous imbibition in a Y-shaped branching network model. The classic Lucas–Washburn equation was used for modeling the imbibition process occurring in the Y-shape model. Then, a mathematical model for the Newtonian fluid’s imbibition was derived to reveal the relationship between dimensionless imbibition time and length ratio, radius ratio, and wetting strength. The dimensionless imbibition time in the model was adopted to compare with that of the capillary bundle model. Different length and radius ratios were considered in the adjacent two-stage channels, and different wettabilities were considered in the different branches. The optimal radius ratio, length ratio, and wetting strength were calculated under the condition of the shortest imbibition time. In addition, the shortest dimensionless imbibition time of the three-stage Y-shaped branching network model was calculated when the wettability changes randomly. The results indicate that the imbibition time changed mostly when the wettability of the second branch changed, and the second branch was the most sensitive to wettability in the model.
Дисертації з теми "Washburn model"
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Barui, Srimanta. "Understanding quantitative process physics of 3D binderjet printing with validation in Ti-6Al-4V and inkjet bioprinting of mammalian cells." Thesis, 2020. https://etd.iisc.ac.in/handle/2005/4615.
Повний текст джерелаАнотація:
In the field of additive manufacturing, laser or electron beam based 3D printing is widely investigated for biomedical applications. However, much less explored is the binderjet 3D printing, which allows processing of biomaterials at physiologically relevant conditions. In this context, this thesis presents a set of experimental and theoretical analysis to develop a quantitative understanding of the transient process physics of the binderjet 3D printing. In the first part, maltodextrin based aqueous binder, deployed to ‘direct’ print Ti-6Al-4V powder with the achieved mechanical properties ranged between cortical and cancellous bone are described. The adopted process induced ~99% interconnectivity in the 3D microstructure, probed using quantitative micro-CT analysis. Finite Element-based analysis was developed to predict the stress-strain response of various designed porous architectures, while assigning an ‘effective’ material property obtained from microporous models without designed porosity.
In the broad second part of the thesis, the formulation of an in situ polymerisable acrylic binder/ink for printing implantable metallic biomaterials is highlighted. The modification of the printable Ti-6Al-4V powders using persulfate, allowed localised polymerisation during the 3D binderjet printing of with the on-demand deposited acrylic ink, In order to establish the theoretical perspective, Washburn’s theory was used to understand the transient kinetics of the ink/binder infiltration phenomena in ~100 µm thick powder bed layers,. The combinatorial experimental/analytical approaches enabled to predict the time required for the transient phenomena involved in binderjet printing. A pertinent combination of statistically reliable strength properties (Weibull modulus, compressive, flexural strength and compressive modulus of ~8, 222 MPa, 93 MPa and 4 GPa, respectively) of Ti-6Al-4V scaffolds was recorded along with ~98% interconnected microporous 3D microstructure. The cytocompatibility of the Ti-6Al-4V 3D architectures was established using mammalian fibroblasts and osteoblasts. In developing a better quantitative insight into ink infiltration kinetics, in the third part of this thesis, real time ink infiltration phenomena in the porous ceramic powder bed was investigated under high brilliance synchrotron X-Ray in refraction based phase contrast mode. An ethylene glycol-DI water based simulated ink was allowed to deposit ‘on-demand’ through a piezoelectric inkjet printhead and the post-impact ink infiltration behaviour through the porous alumina powder bed was captured real-time at a rate of 500 fps. Using a rigorous interactive image analysis, the real time wetting contours were extracted and penetration depth, lateral spread, transformed wetting volume was quantified. Denesuk and Holman’s models based on Washburn’s theory were adapted to develop a theoretical model of wetting volume in real time which was established to be dependent on powder bed porosity.
In the fourth part of this thesis, the experimental results related to the piezoelectric inkjet bioprinting of mammalian cells and the post-printing cell functionalities are demonstrated. Cell laden ‘printable’ bioink was printed through a 60 µm orifice printhead using three driving voltages of 80, 90 and 100 V at 3k Hz frequency. Post-printing proliferation (Alamar blue) of the cells was higher, when printed using higher voltage endorsing the positive effect of smooth and uninterrupted droplet ejectionat higher voltage. Propidium iodide (PI) and Texas red conjugated dextran based hierarchical set of molecular probes (3 kDa, 10 kDa, 40 kDa, and 70 kDa) were used to probe the post-printing cell membrane permeation in real time. An interesting observation is the cell membrane damage, which persisted only for few hours after the printing operation in lower voltage (80V). Importantly, the total area of pores and the maximum pore size are found to vary in accordance with the actuating voltage. As the viability and proliferation are uncompromised in higher printing voltage, the higher lifetime of the finite sized membrane pores can be potentially useful for intra-cellular molecular transfections like gene, protein deliveries for cell engineering applications.Department of Science and Technology (DST), Govt. of India, and particularly FIST funding; Department of Biotechnology ( DBT), Govt. of India; National Network for Mathematical and Computational Biology (NNMCB), SERB, Govt. of India; Commonwealth Scholarship Commission, UK; The cell printing and culture facility of Department of Materials, University of Manchester and Diamond Synchrotron facility (DLS, Oxfordshire), UK
Книги з теми "Washburn model"
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Owen, Nathaniel. A celebration of life: The biography of Diane Washburn. [Philadelphia]: Xlibris Corp., 2008.
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Krohelski, J. T. Simulation of stage and hydrologic budget for Shell Lake, Washburn County, Wisconsin. Middleton, Wis: U.S. Dept. of the Interior, U.S. Geological Survey, 1999.
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Krohelski, J. T. Simulation of stage and hydrologic budget for Shell Lake, Washburn County, Wisconsin. Middleton, Wis: U.S. Dept. of the Interior, U.S. Geological Survey, 1999.
Знайти повний текст джерелаЧастини книг з теми "Washburn model"
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Liu, Guodong, Xinya Zhang, Meiyun Zhang, and Patrick Gane. "Revealing the Components at Work in Classical Liquid Imbibition Models: Inertial, Bosanquet and Viscous Lucas-Washburn Applied to Printing." In Lecture Notes in Electrical Engineering, 987–95. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-3530-2_121.
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Hull, Katy. "Mystic in a Morning Coat." In The Machine Has a Soul, 42–64. Princeton University Press, 2021. http://dx.doi.org/10.23943/princeton/9780691208107.003.0003.
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This chapter investigates how fascist sympathizers saw Benito Mussolini as a man who could simultaneously navigate modernity while moderating its worst effects. Constructed as the austere administrator with a deep soul, sympathizers drew attention to all that Americans had sacrificed in their race to the future and provided recompense for those who felt lost, lonely, or left behind by change. As a model, Mussolini countered the pessimistic notes that inhered in criticisms of American masculinity in contemporary society, to offer the promise of change. Part of the change seemed to rest on policy actions — for instance, in the area of education and youth training — as suggested by Herbert Schneider and Richard Washburn Child. And part seemed to require a shift in attitudes toward Italian-Americans, as argued by Generoso Pope.
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A. Ali, Mohamed, Joël De Coninck, and Hary L. Razafindralambo. "Wettability of Probiotic Powders: Fundamentals, Methodologies, and Applications." In Wetting and Wettability - Fundamental and Applied Aspects [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.106403.
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Wettability is a macroscopic consequence of microscopic phenomena occurring at the fluid-solid interfaces. This functional property is crucial for the formulation of wettable powders in food and non-food sectors. Basically, powder wettability is mostly assessed through the contact angle measurements of solid particles reacting with dispersing media, by either the sessile drop method or the capillary rise technique. Among the most popular bioactive agents nowadays are probiotics and their metabolites, which are receiving a growing interest for their beneficial effects on our ecosystem health. As live functional ingredients, probiotics are mainly available in a powder form that is sensitive to the environmental stress factors during processing and storage steps. It is therefore crucial to understand and control their wettability, regarding their performance, dispersibility, and stability when probiotic particles come into contact with dispersing media and body fluids. The proposal chapter aims to review: (1) the theoretical aspects of powder wettability by considering compact and porous materials; (2) the analytical tools and methodologies of measurement, including sessile drop and capillary rise methods using models Lucas-Washburn equation and Darcy’s law; and (3) the applications to probiotic powders as functional ingredients in food and agricultural sectors.
Тези доповідей конференцій з теми "Washburn model"
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Keshmiri, Kiarash, Neda Nazemifard, and Haibo Huang. "Effects of Wettability on Capillary Flow of Non-Newtonian Fluid in Microchannels." In ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/fedsm2018-83533.
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In this study, capillary filling of diluted bitumen was evaluated using glass etched microchannel. Glass microchannel was treated using Trichloro(1H,1H,2H,2H-perfluorooctyl) silane that makes the microchannel lyophobic (not favorable for neither hydrophilic nor hydrophobic liquids). Water contact angle, as a degree of hydrophilicity, was changed from 15° for untreated microchannel to 115° for treated microchannel. Measured Capillary filling speed of bitumen in hexane (10% to 60%) was experimentally monitored using white light microscope and compared with Washburn theoretical model. For all samples, a linear relation between square of propagation distance and time was found. However, a deviation between experimental and theoretical values of penetration as a function of time was recorded. Experimental results indicated slower velocity compared to theoretical prediction due to simplifications of the Washburn model. Advancing dynamic contact angle of capillary-driven flow was measured and compared with static contact angle using MATLAB®. It was found that dynamic contact angle was increasing during the penetration in microchannel and application of a constant contact angle leads to higher deviation between experimental and theoretical results.
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Ashraf, Shabina, and Jyoti Phirani. "Capillary Impregnation of Viscous Fluids in a Multi-Layered Porous Medium." In ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-5168.
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Abstract Capillary impregnation of viscous fluids in porous media is useful in diagnostics, design of lab-on-chip devices and enhanced oil recovery. The impregnation of a wetting fluid in a homogeneous porous medium follows Washburn’s diffusive law. The diffusive dynamics predicts that, with the increase in permeability, the rate of spontaneous imbibition of a wetting fluid also increases. As most of the naturally occurring porous media are composed of hydrodynamically interacting layers having different properties, the impregnation in a heterogeneous porous medium is significantly different from a homogeneous porous medium. A Washburn like model has been developed in the past to predict the imbibition behavior in the layers for a hydrodynamically interacting three layered porous medium filled with a non-viscous resident phase. It was observed that the relative placement of the layers impacts the imbibition phenomena significantly. In this work, we develop a quasi one-dimensional lubrication approximation to predict the imbibition dynamics in a hydrodynamically interacting multi-layered porous medium. The generalized model shows that the arrangement of layers strongly affects the saturation of wetting phase in the porous medium, which is crucial for oil recovery and in microfluidic applications.
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Ilegbusi, Olusegun J., and Jijin Yang. "Effect of Si-Al Alloy on Kinetics of Reaction-Bonded SiC Infiltration Process." In ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-1255.
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Abstract The kinetics of reaction-bonded SiC infiltration process utilizing Si-Al matrix has been investigated theoretically using a modified Washburn model. The effect of alloy composition and temperature on infiltration has been quantified. The resulting characteristics depend on alloy composition of the secondary metallic phase. Specifically, aluminum generally suppresses the infiltration rate. Increasing the temperature enhances both the infiltration capacity and reaction rate.
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Zheng, Leo, Ying Sun, Timothy Singler, Jeremias Libres, Siva Gurrum, and Patrick Thompson. "Modeling and Experiments of Underfill Flow in Large Dies With Non-Uniform Bump Patterns." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-69006.
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This paper presents numerical modeling and experimental results for the problem of underfill flow in a large die with a non-uniform bump pattern in a flip-chip packaging configuration. Two different 2-D flow models coupled with the volume-of-fluid (VOF) method are applied to track the underfill flow front during the simulation of flip-chip encapsulation. The first model employs the modified Washburn model and uses a time-dependent inlet velocity to account for the flow resistance across the gap direction in the presence of bump interconnects. The second model introduces a momentum source term in the Stokes equation to represent the gapwise resistance. Rheological properties, surface tension, and dynamic contact angles for an underfill material are experimentally determined. Simulation results based on the two models are compared with in-situ flow visualization conducted using bumped quartz dies. The comparison demonstrates the applicability of each model for simulating the underfill encapsulation process.
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Fries, N., K. Odic, M. Conrath, and M. Dreyer. "The Capillary Rise of Liquids in a Metallic Weave: Evaporation Effects." In ASME 2008 6th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2008. http://dx.doi.org/10.1115/icnmm2008-62084.
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Many applications rely on the capillary rise of liquids in porous media. In spacecrafts for example, propellant management devices (PMDs) are used to provide gas free delivery of propellant during all acceleration conditions of the flight. Many PMDs use a metallic weave which, when wetted by the propellant, prevents gas from entering below a critical bubble point pressure. If volatile or cryogenic liquids are used refilling of the weave becomes important as it could dry out and become inoperative. We study the role of evaporation for the capillary rise of different liquids in a dry Dutch Twilled Weave (DTW 200×1400). The Lucas and Washburn model is extended to include evaporation and gravity effects. By comparing the experimental results with the enhanced wicking model we find good qualitative agreement. It is also noted that evaporation may have a major impact on the height gained due to capillary action.
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Moeini Sedeh, Mahmoud, and J. M. Khodadadi. "Experimental Investigation of Wicking Flow Through a Porous Medium as a Validation Approach for Numerical Simulations." In ASME 2013 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/fedsm2013-16466.
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Wicking flow through a porous medium with nearly-spherical interconnected pores was investigated experimentally for validation of numerical simulations of multiphase flow through a porous structure. The experimental setup was designed to eliminate the effects of pressure gradient and gravity. The porous structure is a commercial graphite foam (PocoFoam® with an average pore size of 400 μm and porosity of 75%) and the penetrating liquid is cyclohexane. The penetration of the liquid into the foam sample is unidirectional. The liquid originates from a side reservoir toward an empty reservoir on the opposite side, with the porous sample between the reservoirs. The level of the liquid was kept constant on the fluid source side of the sample, i.e. in the reservoir full of liquid. Since the top side of the experimental setup is exposed to the ambient, there is no pressure gradient effect. Thus, penetration of the liquid occurs only as a result of interfacial effects (i.e. surface tension and contact angle) while pressure gradient and gravity play negligible roles. The instantaneous liquid penetration length (i.e. the average position of liquid interface) versus time was measured experimentally using video frame analysis of the tests recorded with a digital camera aligned with the experimental setup and observing from the top. The experiments were repeated several times to ensure their repeatability and the variations of the liquid interface position were obtained at different time instants. The results exhibit agreement with the theoretical Washburn equation for the liquid penetration length for horizontal wicking along cylindrical capillaries. Moreover, the possible causes of deviations from the Washburn equation were studied. Furthermore, the experimental results are in good agreement with numerical results of the liquid penetration through a series of pores. The numerical analysis was performed for a two-dimensional model that is based on the geometric features of the graphite foam sample and using the multiphase Volume-of-Fluid (VOF) method.
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Choi, Changho, Chih-hung Chang, Shankar Krishnan, Terry J. Hendricks, and Ward TeGrotenhuis. "Capillary Rise and Evaporative Heat Transfer in Nano-Structured Multi-Mode Wicks." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-63776.
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Nanostructured films were successfully deposited on various wick samples including conventional screen materials, engineered single and dual-mode wicks which are specially designed to augment boiling heat transfer performance. Microreactor-assisted nanomaterial deposition, MAND™, was employed with a flow cell to deposit the nanostructures on large wick shims (4.3cm × 10.7cm). Capillary rise experiments, height based measurement and weight gain method, were performed to characterize wicking dynamics in nano-coated and “bare” capillary wicks with water and ethanol. The results indicate that nanocoated wick is most efficient for ethanol in terms of the enhancement of capillary force. Analytical and numerical analyses based on Lucas Washburn equation were performed to model the capillary rise. Data from the height measurement were in a good agreement with both numerical and analytical solutions. Capillary rise of water on engineered multi-mode wicks displayed a step-rise in the wicking front. Flow boiling tests were also performed to characterize heat transfer from nano-coated wicks for application in energy conversion systems as compact evaporators. Experimental results indicate that the nanostructured wicks enhance heat transfer, reduce superheat required and operate stably when compared with “bare” wicks and conventional microchannels.
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Rahman, M. Shafiqur, and Uttam K. Chakravarty. "Characterizations of the Paper-Based Microfluidic Devices Used for Detecting Fentanyl and Related Synthetic Opioids." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-11581.
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Abstract The design and analysis of a paper-based microfluidic analytical device (μPAD) are presented in this paper for the detection of fentanyl and related synthetic opioids. Fentanyl, a synthetic opioid, is an extremely fast-acting synthetic narcotic analgesic having a high potency of approximately 100 to 200 times that of morphine. Detection of fentanyl can be done by colorimetric assays, i.e., spot tests with paper strips and μPADs which offer speed, simplicity of operation, portability, and affordability. The microfluidic behavior of liquid specimen and paper in the μPADs and test strips play a significant role in drug detection methods. Therefore, the study contains the fabrication of the test device using 3D printing and analysis of microfluidic behavior of the paper-based fentanyl test device. A multiphase computational fluid dynamics (CFD) model of a 3D microchannel is developed to evaluate the microfluidic properties. The CFD model incorporates the properties of cellulose and fentanyl solution to determine the flow parameters using the volume of fluid method. Wicking in the cellulose paper is studied analytically considering the Lucas-Washburn equation and Darcy’s law. Experiments with the fabricated μPAD and commercial test-kit samples are also conducted to compare the experimental results with the results for the flow parameters found from the numerical simulation.
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Suciu, Claudiu Valentin. "Thermal Effects on Nano-Energy Absorption Systems (Nano-EAS)." In 2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2008. http://dx.doi.org/10.1115/micronano2008-70039.
Повний текст джерелаАнотація:
Development of intelligent and ecological energy absorption systems (EAS) is important to various fields such as automotive (vehicle suspensions, bumpers, engine mounts), construction (protections against seismic and wind-induced vibrations), and defense (parachuted objects, armors). Usual EAS use composites, shape-memory alloys and foams. Recently, liquid adsorption/desorption in/from nanoporous solids was employed to develop high-performance nano-EAS. Energy loss is based on the well-known capillary phenomenon: external work must be done to spread a non-wetting liquid on a solid surface. Nano-EAS provide considerably higher dissipated energies, about 1–10J/g at deformability of 30–70%, compared with the energy absorption of Ti-Ni alloys, about 0.01–0.05J/g at deformability of 5–8%. For water against hydrophobic nanoporous silica gel (artificial sand), the nano-EAS become ecological; they can be also made intelligent by thermo-electrical control. Relative to thermal effects, Qiao et al. have investigated, for nanoporous silica gel with insufficient coverage of the alkyl-based hydrophobic coating, the problem of hysteresis recovery by increasing the temperature in the range 20∼80°C. Energy loss capacity reduced severely after the first loading-unloading cycle, so, the hysteresis was found as irreversible. Shape of the first hysteresis, the accessible specific pore volume and the desorption pressure were almost unaffected by the temperature change. At temperature augmentation the second hysteresis was partially recovered and when the temperature exceeded 50°C the system became almost fully reusable. Water inflow was found as governed by Laplace-Washburn equation but the outflow process was perceived as thermally aided. On the other hand, Eroshenko et al. have contradictorily obtained for nanoporous silica gel with full coverage of the alkyl-based hydrophobic coating, a stable hysteresis at repeated working cycles. Adsorption pressure decreased and desorption pressure increased at temperature augmentation, this producing a reduction of the hysteresis area and damping. However, the accessible specific pore volume was found as thermally unaffected. Oppositely, both the in- and out-flows were found as governed by Laplace-Washburn equation. In this work, for nanoporous silica gels with partial and full coverage of the alkyl and fluorocarbon based hydrophobic coatings, the thermal effects on the hysteresis and damping performances are studied. Test rig used is a compression-decompression chamber introduced inside of an incubator that allows temperature adjustment in the range of −10∼50°C. Results reveal that, depending on the hydrophobic coating coverage, findings reported by Qiao et al. and Eroshenko et al. are in fact not contradictory but complementary. However, as expected, the accessible specific pore volume was found to decrease at temperature reduction. In order to explain all these apparently opposite experimental findings, a model based on the water cluster size distribution versus temperature, the pore size distribution of silica gel and the ability of water molecules to form hydrogen bonds with the uncovered hydroxyl groups on the solid surface is proposed.
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Kuroda, S., J. Kawakita, T. Fukushima, and S. Tobe. "Importance of the Adhesion of HVOF Sprayed Coatings for Aqueous Corrosion Resistance." In ITSC2001, edited by Christopher C. Berndt, Khiam A. Khor, and Erich F. Lugscheider. ASM International, 2001. http://dx.doi.org/10.31399/asm.cp.itsc2001p1123.
Повний текст джерелаАнотація:
Abstract Importance of coating adhesion in a corrosive environment was studied experimentally. Tensile adhesion strength of HVOF sprayed 316L stainless steel and Hastelloy C coatings were tested in as-sprayed condition as well as after immersion in seawater. It was found that the adhesion strength of the stainless steel coatings degraded rapidly whereas that of the Hastelloy coatings remained almost intact. Specimens with an artificial defect were also immersed in seawater. The cross sectional observation after the test revealed that the corrosion at the coating-substrate interface proceeded much faster with the stainless steel coating as compared to the Ni-base alloy coating. A model experiment to simulate the galvanic corrosion of a coating-substrate couple was carried out and no significant difference in the galvanic current density was found between the two coatings when coupled with the steel substrate. The tightness of the coating-substrate interface was then tested with a fluorescent dye penetration test. The dye could penetrate the boundary between the stainless steel coating and the substrate whereas the boundary between the Ni-base alloy coating and the substrate was so tight that no penetration occurred. The size of the micro-gaps at the coating-substrate boundary was discussed from the viewpoint of classical Washburn-Ridiel theory. It was concluded that such micro-gaps between the coating and substrate must be eliminated for these barrier-type coatings to be used in corrosive environments. Heat treatment was highly effective for suppressing the preferential corrosion at the coating-substrate boundary.