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1
Hibiki, Takashi, and Mamoru Ishii. "Active nucleation site density in boiling systems." International Journal of Heat and Mass Transfer 46, no. 14 (July 2003): 2587–601. http://dx.doi.org/10.1016/s0017-9310(03)00031-0.
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Xiao, Boqi, Guoping Jiang, Dongmei Zheng, Lingxia Chen, and Bingyang Liu. "Calculation of Active Nucleation Site Density in Boiling Systems." Research Journal of Applied Sciences, Engineering and Technology 6, no. 4 (June 20, 2013): 587–92. http://dx.doi.org/10.19026/rjaset.6.4168.
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Qi, Yusen, and James F. Klausner. "Comparison of Nucleation Site Density for Pool Boiling and Gas Nucleation." Journal of Heat Transfer 128, no. 1 (May 27, 2005): 13–20. http://dx.doi.org/10.1115/1.2130399.
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It has been well established that the rate of heat transfer associated with boiling systems is strongly dependent on the nucleation site density. Over many years attempts have been made to predict nucleation site density in boiling systems using a variety of techniques. With the exception of specially prepared surfaces, these attempts have met with little success. This paper presents an experimental investigation of nucleation site density measured on roughly polished brass and stainless steel surfaces for gas nucleation and pool boiling over a large parameter space. A statistical model used to predict the nucleation site density in saturated pool boiling is also investigated. The fluids used for this study, distilled water and ethanol, are moderately wetting and highly wetting, respectively. Using distilled water it has been observed that the trends of nucleation site density versus the inverse of the critical radius are similar for pool boiling and gas nucleation. The nucleation site density is higher for gas nucleation than for pool boiling. An unexpected result has been observed with ethanol as the heat transfer fluid, which casts doubt on the general assumption that heterogeneous nucleation in boiling systems is exclusively seeded by vapor trapping cavities. Due to flooding, few sites are active on the brass surface and at most two are active on the stainless steel surface during gas nucleation experiments. However, nucleation sites readily form in large concentration on both the brass and stainless steel surfaces during pool boiling. The pool boiling nucleation site densities for ethanol on rough and mirror polished brass surfaces are also compared. It shows that there is not a significant difference between the measured nucleation site densities on the smooth and rough surfaces. These results suggest that, in addition to vapor trapping cavities, another mechanism must exist to seed vapor bubble growth in boiling systems.
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Harrison, Alexander D., Katherine Lever, Alberto Sanchez-Marroquin, Mark A. Holden, Thomas F. Whale, Mark D. Tarn, James B. McQuaid, and Benjamin J. Murray. "The ice-nucleating ability of quartz immersed in water and its atmospheric importance compared to K-feldspar." Atmospheric Chemistry and Physics 19, no. 17 (September 9, 2019): 11343–61. http://dx.doi.org/10.5194/acp-19-11343-2019.
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Abstract. Mineral dust particles are thought to be an important type of ice-nucleating particle (INP) in the mixed-phase cloud regime around the globe. While K-rich feldspar (K-feldspar) has been identified as being a particularly important component of mineral dust for ice nucleation, it has been shown that quartz is also relatively ice-nucleation active. Given quartz typically makes up a substantial proportion of atmospheric desert dust, it could potentially be important for cloud glaciation. Here, we survey the ice-nucleating ability of 10 α-quartz samples (the most common quartz polymorph) when immersed in microlitre supercooled water droplets. Despite all samples being α-quartz, the temperature at which they induce freezing varies by around 12 ∘C for a constant active site density. We find that some quartz samples are very sensitive to ageing in both aqueous suspension and air, resulting in a loss of ice-nucleating activity, while other samples are insensitive to exposure to air and water over many months. For example, the ice-nucleation temperatures for one quartz sample shift down by ∼2 ∘C in 1 h and 12 ∘C after 16 months in water. The sensitivity to water and air is perhaps surprising, as quartz is thought of as a chemically resistant mineral, but this observation suggests that the active sites responsible for nucleation are less stable than the bulk of the mineral. We find that the quartz group of minerals is generally less active than K-feldspars by roughly 7 ∘C, although the most active quartz samples are of a similar activity to some K-feldspars with an active site density, ns(T), of 1 cm−2 at −9 ∘C. We also find that the freshly milled quartz samples are generally more active by roughly 5 ∘C than the plagioclase feldspar group of minerals and the albite end member has an intermediate activity. Using both the new and literature data, active site density parameterizations have been proposed for freshly milled quartz, K-feldspar, plagioclase and albite. Combining these parameterizations with the typical atmospheric abundance of each mineral supports previous work that suggests that K-feldspar is the most important ice-nucleating mineral in airborne mineral dust.
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Steinke, I., C. Hoose, O. Möhler, P. Connolly, and T. Leisner. "A new temperature and humidity dependent surface site density approach for deposition ice nucleation." Atmospheric Chemistry and Physics Discussions 14, no. 12 (July 14, 2014): 18499–539. http://dx.doi.org/10.5194/acpd-14-18499-2014.
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Abstract. Deposition nucleation experiments with Arizona Test Dust (ATD) as a surrogate for mineral dusts were conducted at the AIDA cloud chamber at temperatures between 220 and 250 K. The influence of the aerosol size distribution and the cooling rate on the ice nucleation efficiencies was investigated. Ice nucleation active surface site (INAS) densities were calculated to quantify the ice nucleation efficiency as a function of temperature, humidity and the aerosol surface area concentration. Additionally, a contact angle parameterization according to classical nucleation theory was fitted to the experimental data in order to relate the ice nucleation efficiencies to contact angle distributions. From this study it can be concluded that the INAS density formulation is a very useful tool to decribe the temperature and humidity dependent ice nucleation efficiency of ATD particles. Deposition nucleation on ATD particles can be described by a temperature and relative humidity dependent INAS density function ns(T, Sice) with ns(xtherm) = 1.88 × 105 · exp(0.2659 · xtherm) [m−2] (1) where the thermodynamic variable xtherm is defined as xtherm = −(T − 273.2) + (Sice−1) × 100 (2) with Sice>1 and within a temperature range between 226 and 250 K. For lower temperatures, xtherm deviates from a linear behavior with temperature and relative humidity over ice. Two different approaches for describing the time dependence of deposition nucleation initiated by ATD particles are proposed. Box model estimates suggest that the time dependent contribution is only relevant for small cooling rates and low number fractions of ice-active particles.
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Steinke, I., C. Hoose, O. Möhler, P. Connolly, and T. Leisner. "A new temperature- and humidity-dependent surface site density approach for deposition ice nucleation." Atmospheric Chemistry and Physics 15, no. 7 (April 2, 2015): 3703–17. http://dx.doi.org/10.5194/acp-15-3703-2015.
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Abstract. Deposition nucleation experiments with Arizona Test Dust (ATD) as a surrogate for mineral dusts were conducted at the AIDA cloud chamber at temperatures between 220 and 250 K. The influence of the aerosol size distribution and the cooling rate on the ice nucleation efficiencies was investigated. Ice nucleation active surface site (INAS) densities were calculated to quantify the ice nucleation efficiency as a function of temperature, humidity and the aerosol surface area concentration. Additionally, a contact angle parameterization according to classical nucleation theory was fitted to the experimental data in order to relate the ice nucleation efficiencies to contact angle distributions. From this study it can be concluded that the INAS density formulation is a very useful tool to describe the temperature- and humidity-dependent ice nucleation efficiency of ATD particles. Deposition nucleation on ATD particles can be described by a temperature- and relative-humidity-dependent INAS density function ns(T, Sice) with ns(xtherm) = 1.88 ×105 · exp(0.2659 · xtherm) [m−2] , (1) where the temperature- and saturation-dependent function xtherm is defined as xtherm = −(T−273.2)+(Sice−1) ×100, (2) with the saturation ratio with respect to ice Sice >1 and within a temperature range between 226 and 250 K. For lower temperatures, xtherm deviates from a linear behavior with temperature and relative humidity over ice. Also, two different approaches for describing the time dependence of deposition nucleation initiated by ATD particles are proposed. Box model estimates suggest that the time-dependent contribution is only relevant for small cooling rates and low number fractions of ice-active particles.
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Wang, C. H., and V. K. Dhir. "On the Gas Entrapment and Nucleation Site Density During Pool Boiling of Saturated Water." Journal of Heat Transfer 115, no. 3 (August 1, 1993): 670–79. http://dx.doi.org/10.1115/1.2910738.
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A model to describe the effect of wettability on nucleation site density is presented. First, from Helmholtz free energy analysis, a criterion for the entrapment condition in a uniform temperature field is developed. Second, the stability condition of preexisting gas/vapor nuclei during the heating process and the minimum superheat required to initiate nucleation are determined. The prediction of the entrapment condition and the incipient temperature are consistent with the experimental observations made on surfaces having naturally existing cavities. Third, a naturally formed cavity on a heater surface is modeled as a spherical cavity. The cumulative active nucleation site density for a specified contact angle is expressed in terms of the cumulative density of cavities existing on the surface as Na = Pas · Nas where Nas is the heater surface cumulative cavity density with cavity mouth angles less than a specified value and Pas is a function of contact angle and cavity mouth angle. The model successfully predicts active site densities for different contact angles.
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HIBIKI, Takashi, and Mamoru ISHII. "ICONE11-36016 MECHANISTIC MODELING OF ACTIVE NUCLEATION SITE DENSITY IN BOILING SYSTEMS." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2003 (2003): 215. http://dx.doi.org/10.1299/jsmeicone.2003.215.
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Yang, S. R., Z. M. Xu, J. W. Wang, and X. T. Zhao. "On the fractal description of active nucleation site density for pool boiling." International Journal of Heat and Mass Transfer 44, no. 14 (July 2001): 2783–86. http://dx.doi.org/10.1016/s0017-9310(00)00311-2.
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Barthau, G. "Active nucleation site density and pool boiling heat transfer—an experimental study." International Journal of Heat and Mass Transfer 35, no. 2 (February 1992): 271–78. http://dx.doi.org/10.1016/0017-9310(92)90266-u.
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Basu, Nilanjana, Gopinath R. Warrier, and Vijay K. Dhir. "Onset of Nucleate Boiling and Active Nucleation Site Density During Subcooled Flow Boiling." Journal of Heat Transfer 124, no. 4 (July 16, 2002): 717–28. http://dx.doi.org/10.1115/1.1471522.
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The partitioning of the heat flux supplied at the wall is one of the key issues that needs to be resolved if one is to model subcooled flow boiling accurately. The first step in studying wall heat flux partitioning is to account for the various heat transfer mechanisms involved and to know the location at which the onset of nucleate boiling (ONB) occurs. Active nucleation site density data is required to account for the energy carried away by the bubbles departing from the wall. Subcooled flow boiling experiments were conducted using a flat plate copper surface and a nine-rod (zircalloy-4) bundle. The location of ONB during the experiments was determined from visual observations as well as from the thermocouple output. From the data obtained it is found that the heat flux and wall superheat required for inception are dependent on flow rate, liquid subcooling, and contact angle. The existing correlations for ONB underpredict the wall superheat at ONB in most cases. A correlation for predicting the wall superheat and wall heat flux at ONB has been developed from the data obtained in this study and that reported in the literature. Experimental data are within ±30 percent of that predicted from the correlation. Active nucleation site density was determined by manually counting the individual sites in pictures obtained using a CCD camera. Correlations for nucleation site density, which are independent of flow rate and liquid subcooling, but dependent on contact angle have been developed for two ranges of wall superheat—one below 15°C and another above 15°C.
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Tomellini, Massimo. "Evidence for nonclassical nucleation at solid surfaces in diamond deposition from the gas phase." Journal of Materials Research 8, no. 7 (July 1993): 1596–604. http://dx.doi.org/10.1557/jmr.1993.1596.
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In the framework of a previously developed kinetic model, a discriminating criterion is established to distinguish between classical and nonclassical nucleation of diamond at solid surfaces. The two-step model gives the non-steady-state nucleation density function in terms of the rate constants for active site → germ, germ → active site, and germ → nucleus kinetic steps. The criterion states that α/β > 6 is a necessary condition for classical nucleation at surfaces to occur, α and β being functions of the rate constants which can be obtained by appropriate analysis of the experimental data. This criterion is applied to recent results on diamond nucleation at silicon surfaces and indicates nonclassical results The expression of the nonequilibrium Zeldovich factor, Z, is also found in the form Z = [1 + K/nd]−1, K and nd being the rate constants for the germ → nucleus and germ → active site steps, respectively. An estimation of the rate constants is reported and the corresponding Zeldovich factor is evaluated to be 0.6 for nucleation at both Si(100) and Si(111) substrates.
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Surtaev, Anton, Vladimir Serdyukov, and Alexey Safonov. "Characteristics of Boiling Heat Transfer on Hydrophobic Surface." EPJ Web of Conferences 196 (2019): 00054. http://dx.doi.org/10.1051/epjconf/201919600054.
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The paper presents the results of an experimental study of the effect of hydrophobic fluoropolymer coating on the multiscale characteristics of heat transfer at water boiling. New experimental data on dynamics of vapor bubble growth and detachment, evolution of contact line, nucleation site density, heat transfer coefficient were obtained using high-speed imaging techniques, including infrared thermography and video recording from the bottom side of transparent ITO heater. It was shown, that the using of hydrophobic fluoropolymer coating leads to heat transfer enhancement, to decrease of the superheat temperature at the onset of boiling, to increase of the active nucleation site density and to significant change in the dynamics of growth and departure of vapor bubbles and the evolution of the triple contact line.
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XIAO, BOQI. "A NEW ANALYTICAL MODEL FOR HEAT TRANSFER IN POOL BOILING." Modern Physics Letters B 24, no. 12 (May 20, 2010): 1229–36. http://dx.doi.org/10.1142/s0217984910023256.
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In this paper, dependence of active nucleation site density on boiling surfaces are developed. For pool boiling heat transfer, a mathematical model is derived based on statistical treatment using the probability density function of the cavity mouth radius and existing correlation for active nucleation site density, the volume of single bubble at departure, the bubble departure diameter and the bubble departure frequency. The proposed model is expressed as a function of wall superheat, the contact angle, maximum and minimum active cavities, and physical properties of fluid. It is shown that the wall heat flux can be determined by the consideration of the variation of the cavity mouth radius. A good agreement between the proposed model predictions and experimental data is found for different contact angles. It also turns out that the present model explains well the mechanism on how wettability affects the pool boiling.
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Emersic, C., P. J. Connolly, S. Boult, M. Campana, and Z. Li. "Investigating the discrepancy between wet-suspension- and dry-dispersion-derived ice nucleation efficiency of mineral particles." Atmospheric Chemistry and Physics 15, no. 19 (October 12, 2015): 11311–26. http://dx.doi.org/10.5194/acp-15-11311-2015.
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Abstract. Cloud chamber investigations into ice nucleation by mineral particles were compared with results from cold-stage droplet freezing experiments. Kaolinite, NX-illite, and K-feldspar were examined, and K-feldspar was revealed to be the most ice-active mineral particle sample, in agreement with recent cold-stage studies. The ice nucleation efficiencies, as quantified using the ice-active surface site density method, were found to be in agreement with previous studies for the lower temperatures; however, at higher temperatures the efficiency was between a factor of 10 and 1000 higher than those inferred from cold-stage experiments. Numerical process modelling of cloud formation during the experiments, using the cold-stage-derived parameterisations to initiate the ice phase, revealed the cold-stage-derived parameterisations to consistently underpredict the number of ice crystals relative to that observed. We suggest the reason for the underestimation of ice in the model is that the slope of the cold-stage-derived ice-active surface site density vs. temperature curves are too steep, which results in an underestimation of the number of ice crystals at higher temperatures during the expansion. These ice crystals suppress further freezing due to the Bergeron–Findeison process. A coagulation model was used to investigate the idea that the mineral particles coagulate in suspension. This model suggests that coagulation during the experiments may be sufficient to significantly remove the particles for the suspension by sedimentation or reduce the total particle surface area available for ice nucleation to take place. Aggregation was confirmed to take place in mineral suspensions using dynamic light-scattering measurements. However, it is not proven that aggregation of the mineral particles is able to reduce the surface area available for ice nucleation. The implication is that the mineral particles may be more important at nucleating ice at high temperatures than previously thought.
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Hsieh, S. S., C. J. Weng, and J. J. Chiou. "Nucleate Pool Boiling on Ribbed Surfaces With Micro-Roughness at Low and Moderate Heat Flux." Journal of Heat Transfer 121, no. 2 (May 1, 1999): 376–85. http://dx.doi.org/10.1115/1.2825990.
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Nucleate pool boiling correlation was developed for five different rib-type roughened tube geometries (including plain tube) with different rib angles of 30 deg, 45 deg, 60 deg, and 90 deg for both distilled water and R-134a as the working media. A scanning electron micrograph (SEM) examination was made for these horizontal roughened tubes. Bubble departure diameter, frequency of bubble emission, and the active nucleation site density with the influence of the rib angle for this type of roughened surface were obtained. Boiling heat flux incorporating natural convection, nucleate boiling, and microlayer evaporation mechanisms following Benjamin and Balakrishnan (1996) was predicted. Heat transfer correlation was also developed in terms of the degree superheat and active nucleation site density. The dependence for these two parameters was found in favorable agreement with that of previous study for smooth surfaces.
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Beydoun, Hassan, Michael Polen, and Ryan C. Sullivan. "Effect of particle surface area on ice active site densities retrieved from droplet freezing spectra." Atmospheric Chemistry and Physics 16, no. 20 (October 28, 2016): 13359–78. http://dx.doi.org/10.5194/acp-16-13359-2016.
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Abstract. Heterogeneous ice nucleation remains one of the outstanding problems in cloud physics and atmospheric science. Experimental challenges in properly simulating particle-induced freezing processes under atmospherically relevant conditions have largely contributed to the absence of a well-established parameterization of immersion freezing properties. Here, we formulate an ice active, surface-site-based stochastic model of heterogeneous freezing with the unique feature of invoking a continuum assumption on the ice nucleating activity (contact angle) of an aerosol particle's surface that requires no assumptions about the size or number of active sites. The result is a particle-specific property g that defines a distribution of local ice nucleation rates. Upon integration, this yields a full freezing probability function for an ice nucleating particle. Current cold plate droplet freezing measurements provide a valuable and inexpensive resource for studying the freezing properties of many atmospheric aerosol systems. We apply our g framework to explain the observed dependence of the freezing temperature of droplets in a cold plate on the concentration of the particle species investigated. Normalizing to the total particle mass or surface area present to derive the commonly used ice nuclei active surface (INAS) density (ns) often cannot account for the effects of particle concentration, yet concentration is typically varied to span a wider measurable freezing temperature range. A method based on determining what is denoted an ice nucleating species' specific critical surface area is presented and explains the concentration dependence as a result of increasing the variability in ice nucleating active sites between droplets. By applying this method to experimental droplet freezing data from four different systems, we demonstrate its ability to interpret immersion freezing temperature spectra of droplets containing variable particle concentrations. It is shown that general active site density functions, such as the popular ns parameterization, cannot be reliably extrapolated below this critical surface area threshold to describe freezing curves for lower particle surface area concentrations. Freezing curves obtained below this threshold translate to higher ns values, while the ns values are essentially the same from curves obtained above the critical area threshold; ns should remain the same for a system as concentration is varied. However, we can successfully predict the lower concentration freezing curves, which are more atmospherically relevant, through a process of random sampling from g distributions obtained from high particle concentration data. Our analysis is applied to cold plate freezing measurements of droplets containing variable concentrations of particles from NX illite minerals, MCC cellulose, and commercial Snomax bacterial particles. Parameterizations that can predict the temporal evolution of the frozen fraction of cloud droplets in larger atmospheric models are also derived from this new framework.
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Connolly, P. J., O. Möhler, P. R. Field, H. Saathoff, R. Burgess, T. Choularton, and M. Gallagher. "Studies of heterogeneous freezing by three different desert dust samples." Atmospheric Chemistry and Physics Discussions 9, no. 1 (January 8, 2009): 463–514. http://dx.doi.org/10.5194/acpd-9-463-2009.
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Abstract. We present results of experiments at the aerosol interactions and dynamics in the atmosphere (AIDA) chamber facility looking at the freezing of water by three different types of mineral particles at temperatures between −12°C and −33°C. The three different dusts are Asia Dust-1 (AD1), Sahara Dust-2 (SD2) and Arizona test Dust (ATD). The dust samples used had particle concentrations of sizes that were log-normally distributed with mode diameters between 0.3 and 0.5 μm and standard deviations, σg, of 1.6–1.9. The results from the freezing experiments are consistent with the singular hypothesis of ice nucleation. The dusts showed different nucleation abilities, with ATD showing a rather sharp increase in ice-active surface site density at temperatures less than −24°C. AD1 was the next most efficient freezing nuclei and showed a more gradual increase in activity than the ATD sample. SD2 was the least active freezing nuclei. We used data taken with particle counting probes to derive the ice-active surface site density forming on the dust as a function of temperature for each of the three samples and polynomial curves are fitted to this data. The curve fits are then used independently within a bin microphysical model to simulate the ice formation rates from the experiments in order to test the validity of parameterising the data with smooth curves. Good agreement is found between the measurements and the model for AD1 and SD2; however, the curve for ATD does not yield results that agree well with the observations. The reason for this is that more experiments between −20 and −24°C are needed to quantify the rather sharp increase in ice-active surface site density on ATD in this temperature regime. The curves presented can be used as parameterisations in atmospheric cloud models where cooling rates of approximately 1°C min−1 or more are present to predict the concentration of ice crystals forming by the condensation-freezing mode of ice nucleation. Finally a polynomial is fitted to all three samples together in order to have a parameterisation describing the average ice-active surface site density vs. temperature for an equal mixture of the three dust samples.
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Connolly, P. J., O. Möhler, P. R. Field, H. Saathoff, R. Burgess, T. Choularton, and M. Gallagher. "Studies of heterogeneous freezing by three different desert dust samples." Atmospheric Chemistry and Physics 9, no. 8 (April 27, 2009): 2805–24. http://dx.doi.org/10.5194/acp-9-2805-2009.
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Abstract. We present results of experiments at the aerosol interactions and dynamics in the atmosphere (AIDA) chamber facility looking at the freezing of water by three different types of mineral particles at temperatures between −12°C and −33°C. The three different dusts are Asia Dust-1 (AD1), Sahara Dust-2 (SD2) and Arizona test Dust (ATD). The dust samples used had particle concentrations of sizes that were log-normally distributed with mode diameters between 0.3 and 0.5 μm and standard deviations, σg, of 1.6–1.9. The results from the freezing experiments are consistent with the singular hypothesis of ice nucleation. The dusts showed different nucleation abilities, with ATD showing a rather sharp increase in ice-active surface site density at temperatures less than −24°C. AD1 was the next most efficient freezing nuclei and showed a more gradual increase in activity than the ATD sample. SD2 was the least active freezing nuclei. We used data taken with particle counting probes to derive the ice-active surface site density forming on the dust as a function of temperature for each of the three samples and polynomial curves are fitted to this data. The curve fits are then used independently within a bin microphysical model to simulate the ice formation rates from the experiments in order to test the validity of parameterising the data with smooth curves. Good agreement is found between the measurements and the model for AD1 and SD2; however, the curve for ATD does not yield results that agree well with the observations. The reason for this is that more experiments between −20 and −24°C are needed to quantify the rather sharp increase in ice-active surface site density on ATD in this temperature regime. The curves presented can be used as parameterisations in atmospheric cloud models where cooling rates of approximately 1°C min−1 or more are present to predict the concentration of ice crystals forming by the condensation-freezing mode of ice nucleation. Finally a polynomial is fitted to all three samples together in order to have a parameterisation describing the average ice-active surface site density vs. temperature for an equal mixture of the three dust samples.
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Ma, Yue, Feng Wu, Nan Chen, Tianyu Yang, Yaohui Liang, Zhaoyang Sun, Guangqiu Luo, et al. "A Dual Functional Artificial SEI Layer Based on a Facile Surface Chemistry for Stable Lithium Metal Anode." Molecules 27, no. 16 (August 15, 2022): 5199. http://dx.doi.org/10.3390/molecules27165199.
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Solid electrolyte interphase (SEI) on a Li anode is critical to the interface stability and cycle life of Li metal batteries. On the one hand, components of SEI with the passivation effect can effectively hinder the interfacial side reactions to promote long-term cycling stability. On the other hand, SEI species that exhibit the active site effect can reduce the Li nucleation barrier and guide Li deposition homogeneously. However, strategies that only focus on a separated effect make it difficult to realize an ideal overall performance of a Li anode. Herein, a dual functional artificial SEI layer simultaneously combining the passivation effect and the active site effect is proposed and constructed via a facial surface chemistry method. Simultaneously, the formed LiF component effectively passivates the anode/electrolyte interface and contributes to the long-term stable cycling performance, while the Li-Mg solid solution alloy with the active site effect promotes the transmission of Li+ and guides homogeneous Li deposition with a low energy barrier. Benefiting from these advantages, the Li||Li cell with the modified anode performs with a lower nucleation overpotential of 2.3 mV, and an ultralong cycling lifetime of over 2000 h at the current density of 1 mA cm−2, while the Li||LiFePO4 full battery maintains a capacity retention of 84.6% at rate of 1 C after 300 cycles.
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Belosi, Franco, and Gianni Santachiara. "Experimental Study on the Dependency of Ice Nucleation Active Surface Site Density on ATD Aerosol Size." Atmospheric and Climate Sciences 11, no. 03 (2021): 426–40. http://dx.doi.org/10.4236/acs.2021.113025.
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Li, Quan, Yongjun Jiao, Maria Avramova, Ping Chen, Junchong Yu, Jie Chen, and Jason Hou. "Development, verification and application of a new model for active nucleation site density in boiling systems." Nuclear Engineering and Design 328 (March 2018): 1–9. http://dx.doi.org/10.1016/j.nucengdes.2017.12.027.
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Hartmann, S., S. Augustin, T. Clauss, H. Wex, T. Šantl-Temkiv, J. Voigtländer, D. Niedermeier, and F. Stratmann. "Immersion freezing of ice nucleation active protein complexes." Atmospheric Chemistry and Physics 13, no. 11 (June 14, 2013): 5751–66. http://dx.doi.org/10.5194/acp-13-5751-2013.
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Abstract. Utilising the Leipzig Aerosol Cloud Interaction Simulator (LACIS), the immersion freezing behaviour of droplet ensembles containing monodisperse particles, generated from a Snomax™ solution/suspension, was investigated. Thereto ice fractions were measured in the temperature range between −5 °C to −38 °C. Snomax™ is an industrial product applied for artificial snow production and contains Pseudomonas syringae} bacteria which have long been used as model organism for atmospheric relevant ice nucleation active (INA) bacteria. The ice nucleation activity of such bacteria is controlled by INA protein complexes in their outer membrane. In our experiments, ice fractions increased steeply in the temperature range from about −6 °C to about −10 °C and then levelled off at ice fractions smaller than one. The plateau implies that not all examined droplets contained an INA protein complex. Assuming the INA protein complexes to be Poisson distributed over the investigated droplet populations, we developed the CHESS model (stoCHastic modEl of similar and poiSSon distributed ice nuclei) which allows for the calculation of ice fractions as function of temperature and time for a given nucleation rate. Matching calculated and measured ice fractions, we determined and parameterised the nucleation rate of INA protein complexes exhibiting class III ice nucleation behaviour. Utilising the CHESS model, together with the determined nucleation rate, we compared predictions from the model to experimental data from the literature and found good agreement. We found that (a) the heterogeneous ice nucleation rate expression quantifying the ice nucleation behaviour of the INA protein complex is capable of describing the ice nucleation behaviour observed in various experiments for both, Snomax™ and P. syringae bacteria, (b) the ice nucleation rate, and its temperature dependence, seem to be very similar regardless of whether the INA protein complexes inducing ice nucleation are attached to the outer membrane of intact bacteria or membrane fragments, (c) the temperature range in which heterogeneous droplet freezing occurs, and the fraction of droplets being able to freeze, both depend on the actual number of INA protein complexes present in the droplet ensemble, and (d) possible artifacts suspected to occur in connection with the drop freezing method, i.e., the method frequently used by biologist for quantifying ice nucleation behaviour, are of minor importance, at least for substances such as P. syringae, which induce freezing at comparably high temperatures. The last statement implies that for single ice nucleation entities such as INA protein complexes, it is the number of entities present in the droplet population, and the entities' nucleation rate, which control the freezing behaviour of the droplet population. Quantities such as ice active surface site density are not suitable in this context. The results obtained in this study allow a different perspective on the quantification of the immersion freezing behaviour of bacterial ice nucleation.
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Niedermeier, Dennis, Stefanie Augustin-Bauditz, Susan Hartmann, Heike Wex, Karoliina Ignatius, and Frank Stratmann. "Can we define an asymptotic value for the ice active surface site density for heterogeneous ice nucleation?" Journal of Geophysical Research: Atmospheres 120, no. 10 (May 21, 2015): 5036–46. http://dx.doi.org/10.1002/2014jd022814.
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Emersic, C., P. J. Connolly, S. Boult, M. Campana, and Z. Li. "Investigating the discrepancy between wet-suspension and dry-dispersion derived ice nucleation efficiency of mineral particles." Atmospheric Chemistry and Physics Discussions 15, no. 1 (January 12, 2015): 887–929. http://dx.doi.org/10.5194/acpd-15-887-2015.
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Abstract. Cloud chamber investigations into ice nucleation by mineral particles were compared with results from cold stage droplet freezing experiments. Kaolinite, NX-illite, and K-feldspar were examined and K-feldspar was revealed to be the most ice active mineral particle sample, in agreement with recent cold stage studies. The ice nucleation efficiencies, as quantified using the ice active site density method, were found to be in agreement with previous studies for the lower temperatures; however, at higher temperatures the efficiency was consistently higher than those inferred from cold stage experiments. Numerical process modelling of cloud formation during the experiments, using the cold-stage-derived parameterisations to initiate the ice phase, revealed the cold-stage-derived parameterisations to consistently under predict the number of ice crystals relative to that observed. We suggest the reason for the underestimation of ice in the model is that the slope of the cold-stage-derived ice active site density vs temperature curves are too steep, which results in an underestimation of the number of ice crystals at higher temperatures during the expansion. These ice crystals suppress further freezing due to the Bergeron-Findeison process. Application of a coagulation model to the size distribution of mineral particles present in the suspensions as used in the cold-stage-derived parameterisations revealed that it is likely that the mineral particles coagulate in suspension, which either removes the particles from the drops by sedimentation or reduces the total particle surface area available for ice nucleation to take place. This is confirmed with measurements of colloidal suspensions. The implication is that the mineral particles may be more important than previously thought at high temperatures.
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Wang, C. H., and V. K. Dhir. "Effect of Surface Wettability on Active Nucleation Site Density During Pool Boiling of Water on a Vertical Surface." Journal of Heat Transfer 115, no. 3 (August 1, 1993): 659–69. http://dx.doi.org/10.1115/1.2910737.
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Pool boiling of saturated water at 1 atm pressure has been investigated. In the experiments, copper surfaces prepared by following a well-defined procedure were used. The cumulative number density of the cavities and their shapes were determined with an optical microscope. The surface had a mirror finish and had a surface Ra (centerline average) value of less than 0.02 μm. The wettability of the surface was changed by controlling the degree of oxidation of the surface. In the experiments with the primary surface, the wall heat flux and superheat were determined with the help of thermocouples embedded in the test block. The density, spatial distribution, local distribution, and nearest-neighbor distance distribution of active nucleation sites in partial and fully developed nucleate boiling were determined from still pictures.
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Hoose, C., and O. Möhler. "Heterogeneous ice nucleation on atmospheric aerosols: a review of results from laboratory experiments." Atmospheric Chemistry and Physics Discussions 12, no. 5 (May 16, 2012): 12531–621. http://dx.doi.org/10.5194/acpd-12-12531-2012.
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Abstract. A small subset of the atmospheric aerosol population has the ability to induce ice formation at conditions under which ice would not form without them (heterogeneous ice nucleation). While no closed theoretical description of this process and the requirements for good ice nuclei is available, numerous studies have attempted to quantify the ice nucleation ability of different particles empirically in laboratory experiments. In this article, an overview of these results is provided. Ice nucleation onset conditions for various mineral dust, soot, biological, organic and ammonium sulphate particles are summarized. Typical temperature-supersaturation regions can be identified for the onset of ice nucleation of these different particle types, but the various particle sizes and activated fractions reported in different studies have to be taken into account when comparing results obtained with different methodologies. When intercomparing only data obtained under the same conditions, it is found that dust mineralogy is not a consistent predictor of higher or lower ice nucleation ability. However, the broad majority of studies agrees on a reduction of deposition nucleation by various coatings on mineral dust. The ice nucleation active surface site (INAS) density is discussed as a normalized measure for ice nucleation activity. For most immersion and condensation freezing measurements on mineral dust, estimates of the temperature-dependent INAS density agree within about two orders of magnitude. For deposition nucleation on dust, the spread is significantly larger, but a general trend of increasing INAS densities with increasing supersaturation is found. For soot, the presently available results are divergent. Estimated average INAS densities are high for ice-nucleation active bacteria at high subzero temperatures. At the same time, it is shown that some other biological aerosols, like certain pollen grains and fungal spores, are not intrinsically better ice nuclei than dust, but owe their high ice nucleation onsets to their large sizes. Surface-area-dependent parameterizations of heterogeneous ice nucleation are discussed. For immersion freezing on mineral dust, fitted INAS densities are available, but should not be used outside the temperature interval of the data they were based on. Classical nucleation theory, if employed with one fitted contact angle, does not reproduce the observed temperature dependence for immersion nucleation, temperature and supersaturation dependence for deposition nucleation, and time dependence.
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Vepuri, Hemanth S. K., Larissa Lacher, Jens Nadolny, Ottmar Möhler, and Naruki Hiranuma. "Online Ice-Nucleating Particle Measurements in the Southern Great Plains (SGP) Using the Portable Ice Nucleation Experiment (PINE) Chamber." Environmental Sciences Proceedings 4, no. 1 (November 17, 2020): 25. http://dx.doi.org/10.3390/ecas2020-08469.
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We present our field results of ice-nucleating particle (INP) measurements from the commercialized version of the Portable Ice Nucleation Experiment (PINE) chamber from two different campaigns. Our first field campaign, TxTEST, was conducted at West Texas A&M University (July–August 2019), and the other campaign, ExINP-SGP, was held at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site (October–November 2019). In both campaigns, the PINE made semi-autonomous INP measurements at a high-time-resolution of 8 min for individual expansions with continuous temperature scans from −5 to −35 °C in 90 min. The PINE instrument was set to have a minimum detection capability of ~0.3 INPs per liter of air. To complement our online PINE measurements, polycarbonate filter impactor and liquid impinger samples were also collected next to the PINE. Offline droplet-freezing assays were later conducted from the filter and impinger samples for the immersion freezing mode. Our preliminary results suggested that the immersion freezing mode was the dominant ice-nucleation mechanism at the SGP site compared to the deposition mode. We did not find any statistical correlation between cloud condensation nuclei (CCN) and INP concentration during our ExINP-SGP period, suggesting that CCN activation is not a significant prerequisite for ice nucleation at the SGP site. In addition, we analyzed the relationship between various aerosol particle size ranges and INP abundance. At SGP, we found an increase in INPs with the super-micron particles, especially for diameters >2 μm across the entire heterogeneous freezing temperature range examined by PINE. Lastly, we computed a variety of INP parameters, such as, ice nucleation active surface site density, water activity-based freezing, and cumulative INP per liter of air, representing the ambient INPs in the SGP. Our field campaign results demonstrated the PINE’s ability to make remote INP measurements, promising future long-term operations including at isolated locations.
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Sullivan, S. C., R. Morales Betancourt, D. Barahona, and A. Nenes. "Understanding cirrus ice crystal number variability for different heterogeneous ice nucleation spectra." Atmospheric Chemistry and Physics Discussions 15, no. 15 (August 11, 2015): 21671–711. http://dx.doi.org/10.5194/acpd-15-21671-2015.
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Abstract. Along with minimizing parameter uncertainty, understanding the cause of temporal and spatial variability of nucleated ice crystal number, Ni, is key to improving the representation of cirrus clouds in climate models. To this end, sensitivities of Ni to input variables like aerosol number and diameter provide valuable information about nucleation regime and efficiency for a given model formulation. Here we use the adjoint model of the Barahona and Nenes cirrus formation parameterization to understand Ni variability for various ice-nucleating particle (INP) spectra. Inputs are generated with the Community Atmosphere Model version 5, and simulations are done with a theoretically-derived spectrum, a lab-based empirical spectrum, and two field-based empirical spectra that differ in the nucleation threshold for black carbon aerosol and in the active site density for dust. The magnitude and sign of Ni sensitivity to insoluble aerosol number can be directly linked to nucleation regime and efficiency of various INP. The lab-based spectrum calculates much higher INP efficiencies than field-based ones, which reveals a disparity in aerosol surface properties. Ni sensitivity to temperature tends to be low, due to the compensating effects of temperature on INP spectrum parameters; this low temperature sensitivity regime has been experimentally reported before but never unraveled as done here.
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Yang, Chunbang, Jiejin Cai, and Sihong He. "Evaluation of various active nucleation site density models of subcooled flow boiling in a vertical tube using OpenFOAM." Progress in Nuclear Energy 138 (August 2021): 103800. http://dx.doi.org/10.1016/j.pnucene.2021.103800.
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Narezo Guzman, Daniela, Yanbo Xie, Songyue Chen, David Fernandez Rivas, Chao Sun, Detlef Lohse, and Guenter Ahlers. "Heat-flux enhancement by vapour-bubble nucleation in Rayleigh–Bénard turbulence." Journal of Fluid Mechanics 787 (December 17, 2015): 331–66. http://dx.doi.org/10.1017/jfm.2015.701.
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We report on the enhancement of turbulent convective heat transport due to vapour-bubble nucleation at the bottom plate of a cylindrical Rayleigh–Bénard sample (aspect ratio 1.00, diameter 8.8 cm) filled with liquid. Microcavities acted as nucleation sites, allowing for well-controlled bubble nucleation. Only the central part of the bottom plate with a triangular array of microcavities (etched over an area with diameter of 2.5 cm) was heated. We studied the influence of the cavity density and of the superheat $T_{b}-T_{on}$ ($T_{b}$ is the bottom-plate temperature and $T_{on}$ is the value of $T_{b}$ below which no nucleation occurred). The effective thermal conductivity, as expressed by the Nusselt number $\mathit{Nu}$, was measured as a function of the superheat by varying $T_{b}$ and keeping a fixed difference $T_{b}-T_{t}\simeq 16$ K ($T_{t}$ is the top-plate temperature). Initially $T_{b}$ was much larger than $T_{on}$ (large superheat), and the cavities vigorously nucleated vapour bubbles, resulting in two-phase flow. Reducing $T_{b}$ in steps until it was below $T_{on}$ resulted in cavity deactivation, i.e. in one-phase flow. Once all cavities were inactive, $T_{b}$ was increased again, but they did not reactivate. This led to one-phase flow for positive superheat. The heat transport of both one- and two-phase flow under nominally the same thermal forcing and degree of superheat was measured. The Nusselt number of the two-phase flow was enhanced relative to the one-phase system by an amount that increased with increasing $T_{b}$. Varying the cavity density (69, 32, 3.2, 1.2 and $0.3~\text{mm}^{-2}$) had only a small effect on the global $\mathit{Nu}$ enhancement; it was found that $\mathit{Nu}$ per active site decreased as the cavity density increased. The heat-flux enhancement of an isolated nucleating site was found to be limited by the rate at which the cavity could generate bubbles. Local bulk temperatures of one- and two-phase flows were measured at two positions along the vertical centreline. Bubbles increased the liquid temperature (compared to one-phase flow) as they rose. The increase was correlated with the heat-flux enhancement. The temperature fluctuations, as well as local thermal gradients, were reduced (relative to one-phase flow) by the vapour bubbles. Blocking the large-scale circulation around the nucleating area, as well as increasing the effective buoyancy of the two-phase flow by thermally isolating the liquid column above the heated area, increased the heat-flux enhancement.
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Hoose, C., and O. Möhler. "Heterogeneous ice nucleation on atmospheric aerosols: a review of results from laboratory experiments." Atmospheric Chemistry and Physics 12, no. 20 (October 29, 2012): 9817–54. http://dx.doi.org/10.5194/acp-12-9817-2012.
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Abstract. A small subset of the atmospheric aerosol population has the ability to induce ice formation at conditions under which ice would not form without them (heterogeneous ice nucleation). While no closed theoretical description of this process and the requirements for good ice nuclei is available, numerous studies have attempted to quantify the ice nucleation ability of different particles empirically in laboratory experiments. In this article, an overview of these results is provided. Ice nucleation "onset" conditions for various mineral dust, soot, biological, organic and ammonium sulfate particles are summarized. Typical temperature-supersaturation regions can be identified for the "onset" of ice nucleation of these different particle types, but the various particle sizes and activated fractions reported in different studies have to be taken into account when comparing results obtained with different methodologies. When intercomparing only data obtained under the same conditions, it is found that dust mineralogy is not a consistent predictor of higher or lower ice nucleation ability. However, the broad majority of studies agrees on a reduction of deposition nucleation by various coatings on mineral dust. The ice nucleation active surface site (INAS) density is discussed as a simple and empirical normalized measure for ice nucleation activity. For most immersion and condensation freezing measurements on mineral dust, estimates of the temperature-dependent INAS density agree within about two orders of magnitude. For deposition nucleation on dust, the spread is significantly larger, but a general trend of increasing INAS densities with increasing supersaturation is found. For soot, the presently available results are divergent. Estimated average INAS densities are high for ice-nucleation active bacteria at high subzero temperatures. At the same time, it is shown that INAS densities of some other biological aerosols, like certain pollen grains, fungal spores and diatoms, tend to be similar to those of dust. These particles may owe their high ice nucleation onsets to their large sizes. Surface-area-dependent parameterizations of heterogeneous ice nucleation are discussed. For immersion freezing on mineral dust, fitted INAS densities are available, but should not be used outside the temperature interval of the data they were based on. Classical nucleation theory, if employed with only one fitted contact angle, does not reproduce the observed temperature dependence for immersion nucleation, the temperature and supersaturation dependence for deposition nucleation, and the time dependence of ice nucleation. Formulations of classical nucleation theory with distributions of contact angles offer possibilities to overcome these weaknesses.
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Thorncroft, G. E., J. F. Klausner, and R. Mei. "Suppression of Flow Boiling Nucleation." Journal of Heat Transfer 119, no. 3 (August 1, 1997): 517–24. http://dx.doi.org/10.1115/1.2824130.
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A simple model is presented for estimating the ratio of the maximum to minimum cavity radius required for ebullition in two-phase flow with heat transfer. The resulting dimensionless parameter, rmax/rmin, is demonstrated to correlate flow boiling nucleation site density. As the convective heat transfer associated with bulk turbulence in two-phase flow is enhanced, rmax→rmin, and the probability of finding surface cavities whose radii lie between rmaxandrmin is reduced. Thus, active nucleation sites become deactivated. A vertical flow boiling facility was fabricated in which the nucleation suppression point can be measured. Experiments conducted for mass flux ranging from 183–315 kg/m2-s and inlet quality ranging from 0–0.151, along with data available from the literature, suggest that rmax/rmin is the leading order dimensionless parameter on which the complete suppression of nucleation sites depends. Although the suppression of nucleation sites also depends, to a certain extent, on the surface/fluid combination and heat flux, it is found that complete suppression occurs for rmax/rmin ranging from 40 to 120. This is proposed as a criterion to discriminate the purely convective regime from the nucleate boiling regime.
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Sullivan, Sylvia C., Ricardo Morales Betancourt, Donifan Barahona, and Athanasios Nenes. "Understanding cirrus ice crystal number variability for different heterogeneous ice nucleation spectra." Atmospheric Chemistry and Physics 16, no. 4 (March 3, 2016): 2611–29. http://dx.doi.org/10.5194/acp-16-2611-2016.
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Abstract. Along with minimizing parameter uncertainty, understanding the cause of temporal and spatial variability of the nucleated ice crystal number, Ni, is key to improving the representation of cirrus clouds in climate models. To this end, sensitivities of Ni to input variables like aerosol number and diameter provide valuable information about nucleation regime and efficiency for a given model formulation. Here we use the adjoint model of the adjoint of a cirrus formation parameterization (Barahona and Nenes, 2009b) to understand Ni variability for various ice-nucleating particle (INP) spectra. Inputs are generated with the Community Atmosphere Model version 5, and simulations are done with a theoretically derived spectrum, an empirical lab-based spectrum and two field-based empirical spectra that differ in the nucleation threshold for black carbon particles and in the active site density for dust. The magnitude and sign of Ni sensitivity to insoluble aerosol number can be directly linked to nucleation regime and efficiency of various INP. The lab-based spectrum calculates much higher INP efficiencies than field-based ones, which reveals a disparity in aerosol surface properties. Ni sensitivity to temperature tends to be low, due to the compensating effects of temperature on INP spectrum parameters; this low temperature sensitivity regime has been experimentally reported before but never deconstructed as done here.
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Hiranuma, Naruki, Kouji Adachi, David M. Bell, Franco Belosi, Hassan Beydoun, Bhaskar Bhaduri, Heinz Bingemer, et al. "A comprehensive characterization of ice nucleation by three different types of cellulose particles immersed in water." Atmospheric Chemistry and Physics 19, no. 7 (April 10, 2019): 4823–49. http://dx.doi.org/10.5194/acp-19-4823-2019.
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Abstract. We present the laboratory results of immersion freezing efficiencies of cellulose particles at supercooled temperature (T) conditions. Three types of chemically homogeneous cellulose samples are used as surrogates that represent supermicron and submicron ice-nucleating plant structural polymers. These samples include microcrystalline cellulose (MCC), fibrous cellulose (FC) and nanocrystalline cellulose (NCC). Our immersion freezing dataset includes data from various ice nucleation measurement techniques available at 17 different institutions, including nine dry dispersion and 11 aqueous suspension techniques. With a total of 20 methods, we performed systematic accuracy and precision analysis of measurements from all 20 measurement techniques by evaluating T-binned (1 ∘C) data over a wide T range (−36 ∘C <T<-4 ∘C). Specifically, we intercompared the geometric surface area-based ice nucleation active surface site (INAS) density data derived from our measurements as a function of T, ns,geo(T). Additionally, we also compared the ns,geo(T) values and the freezing spectral slope parameter (Δlog(ns,geo)/ΔT) from our measurements to previous literature results. Results show all three cellulose materials are reasonably ice active. The freezing efficiencies of NCC samples agree reasonably well, whereas the diversity for the other two samples spans ≈ 10 ∘C. Despite given uncertainties within each instrument technique, the overall trend of the ns,geo(T) spectrum traced by the T-binned average of measurements suggests that predominantly supermicron-sized cellulose particles (MCC and FC) generally act as more efficient ice-nucleating particles (INPs) than NCC with about 1 order of magnitude higher ns,geo(T).
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DeMott, P. J., A. J. Prenni, G. R. McMeeking, R. C. Sullivan, M. D. Petters, Y. Tobo, M. Niemand, et al. "Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles." Atmospheric Chemistry and Physics Discussions 14, no. 11 (June 27, 2014): 17359–400. http://dx.doi.org/10.5194/acpd-14-17359-2014.
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Abstract. Data from both laboratory studies and atmospheric measurements are used to develop a simple parametric description for the immersion freezing activity of natural mineral dust particles. Measurements made with the Colorado State University (CSU) continuous flow diffusion chamber (CFDC) when processing mineral dust aerosols at a nominal 105% relative humidity with respect to water (RHw) are taken to approximate the immersion freezing nucleation activity of particles. Ice active frozen fractions vs. temperature for dusts representative of Saharan and Asian desert sources were consistent with similar measurements in atmospheric dust plumes for a limited set of comparisons available. The parameterization developed follows the form of one suggested previously for atmospheric particles of non-specific composition in quantifying ice nucleating particle concentrations as functions of temperature and the total number concentration of particles larger than 0.5 μm diameter. Such an approach does not explicitly account for surface area and time dependencies for ice nucleation, but sufficiently encapsulates the activation properties for potential use in regional and global modeling simulations, and possible application in developing remote sensing retrievals for ice nucleating particles. A correction factor is introduced to account for the apparent underestimate (by approximately 3, on average) of the immersion freezing fraction of mineral dust particles for CSU CFDC data processed at an RHw of 105% vs. maximum fractions active at higher RHw. Instrumental factors that affect activation behavior vs. RHw in CFDC instruments remain to be fully explored in future studies. Nevertheless, the use of this correction factor is supported by comparison to ice activation data obtained for the same aerosols from Aerosol Interactions and Dynamics of the Atmosphere (AIDA) expansion chamber cloud parcel experiments. Further comparison of the new parameterization to the immersion freezing surface active site density parameterization for mineral dust particles, developed separately from AIDA experimental data alone, shows excellent agreement for data collected in a descent through a Saharan aerosol layer. These studies support the utility of laboratory measurements to obtain atmospherically-relevant data on the ice nucleation properties of dust and other particle types, and suggest the suitability of considering all mineral dust as a single type of ice nucleating particle as a useful first order approximation in numerical modeling investigations.
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DeMott, P. J., A. J. Prenni, G. R. McMeeking, R. C. Sullivan, M. D. Petters, Y. Tobo, M. Niemand, et al. "Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles." Atmospheric Chemistry and Physics 15, no. 1 (January 13, 2015): 393–409. http://dx.doi.org/10.5194/acp-15-393-2015.
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Abstract. Data from both laboratory studies and atmospheric measurements are used to develop an empirical parameterization for the immersion freezing activity of natural mineral dust particles. Measurements made with the Colorado State University (CSU) continuous flow diffusion chamber (CFDC) when processing mineral dust aerosols at a nominal 105% relative humidity with respect to water (RHw) are taken as a measure of the immersion freezing nucleation activity of particles. Ice active frozen fractions vs. temperature for dusts representative of Saharan and Asian desert sources were consistent with similar measurements in atmospheric dust plumes for a limited set of comparisons available. The parameterization developed follows the form of one suggested previously for atmospheric particles of non-specific composition in quantifying ice nucleating particle concentrations as functions of temperature and the total number concentration of particles larger than 0.5 μm diameter. Such an approach does not explicitly account for surface area and time dependencies for ice nucleation, but sufficiently encapsulates the activation properties for potential use in regional and global modeling simulations, and possible application in developing remote sensing retrievals for ice nucleating particles. A calibration factor is introduced to account for the apparent underestimate (by approximately 3, on average) of the immersion freezing fraction of mineral dust particles for CSU CFDC data processed at an RHw of 105% vs. maximum fractions active at higher RHw. Instrumental factors that affect activation behavior vs. RHw in CFDC instruments remain to be fully explored in future studies. Nevertheless, the use of this calibration factor is supported by comparison to ice activation data obtained for the same aerosols from Aerosol Interactions and Dynamics of the Atmosphere (AIDA) expansion chamber cloud parcel experiments. Further comparison of the new parameterization, including calibration correction, to predictions of the immersion freezing surface active site density parameterization for mineral dust particles, developed separately from AIDA experimental data alone, shows excellent agreement for data collected in a descent through a Saharan aerosol layer. These studies support the utility of laboratory measurements to obtain atmospherically relevant data on the ice nucleation properties of dust and other particle types, and suggest the suitability of considering all mineral dust as a single type of ice nucleating particle as a useful first-order approximation in numerical modeling investigations.
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Chen, Jingchuan, Zhijun Wu, Jie Chen, Naama Reicher, Xin Fang, Yinon Rudich, and Min Hu. "Size-resolved atmospheric ice-nucleating particles during East Asian dust events." Atmospheric Chemistry and Physics 21, no. 5 (March 8, 2021): 3491–506. http://dx.doi.org/10.5194/acp-21-3491-2021.
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Abstract. Asian dust is an important source of atmospheric ice-nucleating particles (INPs). However, the freezing activity of airborne Asian dust, especially its sensitivity to particle size, is poorly understood. In this study we report the first INP measurement of size-resolved airborne mineral dust collected during East Asian dust events. The measured total INP concentrations in the immersion mode ranged from 10−2 to 102 L−1 in dust events at temperatures between −25 and −5 ∘C. The average contributions of heat-sensitive INPs at three temperatures, −10, −15, and −20 ∘C, were 81±12 %, 70±15 %, and 38±21 %, respectively, suggesting that proteinaceous biological materials have a substantial effect on the ice nucleation properties of Asian airborne mineral dust at high temperatures. The dust particles which originated from China's northwest deserts are more efficient INPs compared to those from northern regions. In general, there was no significant difference in the ice nucleation properties between East Asian dust particles and other regions in the world. An explicit size dependence of both INP concentration and surface ice-active-site density was observed. The nucleation efficiency of dust particles increased with increasing particle size, while the INP concentration first increased rapidly and then leveled, due to the significant decrease in the number concentration of larger particles. A new set of parameterizations for INP activity based on size-resolved nucleation properties of Asian mineral dust particles were developed over an extended temperature range (−35 to −6 ∘C). These size-dependent parameterizations require only particle size distribution as input and can be easily applied in models.
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Lee, Na hyeon, Ki Yun Lee, Yo Han Kim, Seungyeon Jo, and Jae-Ha Myung. "Co-Exsolution Method Via Seeded Effect for Catalytically Active Anode in Protonic Ceramic Fuel Cells." ECS Meeting Abstracts MA2022-01, no. 55 (July 7, 2022): 2305. http://dx.doi.org/10.1149/ma2022-01552305mtgabs.
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Protonic ceramic fuel cells (PCFCs) have great potential in terms of reducing the operating temperature (400-600oC), because of the low activation energy of proton conduction in oxides compared to oxygen ion conduction. These characteristics provide a pathway to overcome the limitation of conventional SOFC (600-1000oC) such as durability, degradation of catalysts. However, poor catalyst activity at low operating temperatures still remains a problem to be solved. One promising way to improve catalytic activity is in-situ exsolution of various metal nanoparticles. Exsolved nanoparticles not only increase the active catalytic area but also have excellent resistance to thermal agglomeration and carbon coking. Unfortunately, it is difficult to achieve a high population density of metal nanoparticles due to the low exsolution kinetics (diffusion, nucleation) in the anode atmospheres of PCFC. In this study, we designed an A-site deficiency proton-conducting oxide, Ba0.9(Zr0.1Ce0.7Y0.1Yb0.1)0.95M0.05O3-d, as a host material to maximize exsolution behaviors. In addition, a co-exsolution strategy with Cu, which has the highest reducibility among transition metals, was introduced to achieve a high population density of exsolved atoms at low temperatures. A single doped Ni metal in the designed host material exhibited a population density value of 1.13 particles/um2 in reducing atmosphere at 600oC. The single doped Cu metal showed 24.1 particles/um2, but Co-doped with Ni and Cu metal produced the highest particle population of 98.31/um2, which is 87 times greater than a single Ni doping. These results follow the seeded growth mechanism induced by the additional surface energy of pre-exsolved Cu. This suggests a new synergy effect on exsolution phenomena that enhances segregation and nucleation kinetics Figure 1
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Kulkarni, Gourihar, Naruki Hiranuma, Ottmar Möhler, Kristina Höhler, Swarup China, Daniel J. Cziczo, and Paul J. DeMott. "A new method for operating a continuous-flow diffusion chamber to investigate immersion freezing: assessment and performance study." Atmospheric Measurement Techniques 13, no. 12 (December 9, 2020): 6631–43. http://dx.doi.org/10.5194/amt-13-6631-2020.
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Abstract. Glaciation in mixed-phase clouds predominantly occurs through the immersion-freezing mode where ice-nucleating particles (INPs) immersed within supercooled droplets induce the nucleation of ice. Model representations of this process currently are a large source of uncertainty in simulating cloud radiative properties, so to constrain these estimates, continuous-flow diffusion chamber (CFDC)-style INP devices are commonly used to assess the immersion-freezing efficiencies of INPs. This study explored a new approach to operating such an ice chamber that provides maximum activation of particles without droplet breakthrough and correction factor ambiguity to obtain high-quality INP measurements in a manner that previously had not been demonstrated to be possible. The conditioning section of the chamber was maintained at −20 ∘C and water relative humidity (RHw) conditions of 113 % to maximize the droplet activation, and the droplets were supercooled with an independently temperature-controlled nucleation section at a steady cooling rate (0.5 ∘C min−1) to induce the freezing of droplets and evaporation of unfrozen droplets. The performance of the modified compact ice chamber (MCIC) was evaluated using four INP species: K-feldspar, illite-NX, Argentinian soil dust, and airborne soil dusts from an arable region that had shown ice nucleation over a wide span of supercooled temperatures. Dry-dispersed and size-selected K-feldspar particles were generated in the laboratory. Illite-NX and soil dust particles were sampled during the second phase of the Fifth International Ice Nucleation Workshop (FIN-02) campaign, and airborne soil dust particles were sampled from an ambient aerosol inlet. The measured ice nucleation efficiencies of model aerosols that had a surface active site density (ns) metric were higher but mostly agreed within 1 order of magnitude compared to results reported in the literature.
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Zhou, Pei, Ronghua Huang, Sheng Huang, Yu Zhang, and Xiaoxuan Rao. "Experimental investigation on active nucleation site density and bubble departure frequency in subcooled flow boiling by using bubble tracking algorithm." International Journal of Heat and Mass Transfer 148 (February 2020): 119081. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2019.119081.
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Kiselev, Alexei A., Alice Keinert, Tilia Gaedeke, Thomas Leisner, Christoph Sutter, Elena Petrishcheva, and Rainer Abart. "Effect of chemically induced fracturing on the ice nucleation activity of alkali feldspar." Atmospheric Chemistry and Physics 21, no. 15 (August 9, 2021): 11801–14. http://dx.doi.org/10.5194/acp-21-11801-2021.
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Abstract. Feldspar is an important constituent of airborne mineral dust. Some alkali feldspars exhibit particularly high ice nucleation (IN) activity. This has been related to structural similarities of the ice (101‾0) prism planes and the (100) planes of alkali feldspar. Here the effect of generating feldspar surfaces with close to (100) orientation by means of chemically induced fracturing on the IN activity of alkali feldspar was investigated experimentally. To this end, gem-quality K-rich alkali feldspar was shifted towards more Na-rich compositions by cation exchange with an NaCl–KCl salt melt at 850 ∘C. By this procedure, a system of parallel cracks with an orientation close to the (100) plane of the feldspar was induced. Droplet-freezing assay experiments performed on grain mounts of the cation-exchanged alkali feldspars revealed an increase in the overall density of ice-nucleating active site (INAS) density with respect to the untreated feldspar. In addition, annealing at 550 ∘C subsequent to primary cation exchange further enhanced the INAS density and led to IN activity at exceptionally high temperatures. Although very efficient in experiment, fracturing by cation exchange with an alkali halide salt is unlikely to be of relevance in the conditioning of alkali feldspars in nature. However, parting planes with similar orientation as the chemically induced cracks may be generated in lamellar microstructures resulting from the exsolution of initially homogeneous alkali feldspar, a widespread phenomenon in natural alkali feldspar known as perthite formation. Perthitic alkali feldspars indeed show the highest IN activity. We tentatively ascribe this phenomenon to the preferential exposure of feldspar crystal surfaces oriented sub-parallel to (100).
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Abdollahzadeh Jamalabadi, Mohammad, Milad Ghasemi, Rezvan Alamian, Somchai Wongwises, Masoud Afrand, and Mostafa Shadloo. "Modeling of Subcooled Flow Boiling with Nanoparticles under the Influence of a Magnetic Field." Symmetry 11, no. 10 (October 11, 2019): 1275. http://dx.doi.org/10.3390/sym11101275.
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Subcooled flow boiling is one of the major issues in the nuclear and power generation industries. If the fluid inlet temperature in the boiling area is less than the boiling temperature, the boiling process is called subcooled boiling. The symmetry of a physical system is a constant property of the system and is fixed by deformation. Using magnetohydrodynamic (MHD) forces and broken symmetry induced by nanosized particles, fluid and thermal systems can be more controlled. In this study, the effect of a magnetic field and nanoparticles on subcooled flow boiling in a vertical tube was investigated. For this purpose, a one-dimensional numerical code was used to simulate the flow and variations of various parameters that have been investigated and evaluated. The results showed that as the flow entered the heated area, the vapor volume fraction, Froude number, fluid cross-sectional area forces, mixture velocity, fluid velocity, bubble departure diameter, liquid and vapor Reynolds numbers, squared ratio of the Froude number to the Weber number, and fluid cross-sectional area forces coefficient increased. In the same region, the Eötvös number, root mean square (RMS) of the fluid cross-sectional area force, sound velocity, liquid superficial velocity, critical tube diameter, bubble departure frequency, and density of the active nucleation site were reduced. It was also observed that after the heated area and under the influence of the magnetic field and the nanoparticles, the values of the vapor volume fraction, Froude number, fluid cross-sectional area force, mixture velocity, fluid velocity, vapor, liquid Reynolds number, and squared ratio of the Froude number to the Weber number were decreased. Moreover, there was no significant effect on the Eötvös number, liquid superficial velocity, Taylor bubble Sauter mean diameter, bubble departure diameter, critical tube diameter, bubble departure frequency, or density of the active nucleation site.
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Yeoh, Guan Heng, and Xiaobin Zhang. "Computational fluid dynamics and population balance modelling of nucleate boiling of cryogenic liquids: Theoretical developments." Journal of Computational Multiphase Flows 8, no. 4 (November 22, 2016): 178–200. http://dx.doi.org/10.1177/1757482x16674217.
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The main focus in the analysis of pool or flow boiling in saturated or subcooled conditions is the basic understanding of the phase change process through the heat transfer and wall heat flux partitioning at the heated wall and the two-phase bubble behaviours in the bulk liquid as they migrate away from the heated wall. This paper reviews the work in this rapid developing area with special reference to modelling nucleate boiling of cryogenic liquids in the context of computational fluid dynamics and associated theoretical developments. The partitioning of the wall heat flux at the heated wall into three components – single-phase convection, transient conduction and evaporation – remains the most popular mechanistic approach in predicting the heat transfer process during boiling. Nevertheless, the respective wall heat flux components generally require the determination of the active nucleation site density, bubble departure diameter and nucleation frequency, which are crucial to the proper prediction of the heat transfer process. Numerous empirical correlations presented in this paper have been developed to ascertain these three important parameters with some degree of success. Albeit the simplicity of empirical correlations, they remain applicable to only a narrow range of flow conditions. In order to extend the wall heat flux partitioning approach to a wider range of flow conditions, the fractal model proposed for the active nucleation site density, force balance model for bubble departing from the cavity and bubble lifting off from the heated wall and evaluation of nucleation frequency based on fundamental theory depict the many enhancements that can improve the mechanistic model predictions. The macroscopic consideration of the two-phase boiling in the bulk liquid via the two-fluid model represents the most effective continuum approach in predicting the volume fraction and velocity distributions of each phase. Nevertheless, the interfacial mass, momentum and energy exchange terms that appear in the transport equations generally require the determination of the Sauter mean diameter or interfacial area concentration, which strongly governs the fluid flow and heat transfer in the bulk liquid. In order to accommodate the dynamically changing bubble sizes that are prevalent in the bulk liquid, the mechanistic approach based on the population balance model allows the appropriate prediction of local distributions of Sauter mean diameter or interfacial area concentration, which in turn can improve the predictions of the interfacial mass, momentum and energy exchanges that occur across the interface between the phases. Need for further developments are discussed.
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Reicher, Naama, Carsten Budke, Lukas Eickhoff, Shira Raveh-Rubin, Ifat Kaplan-Ashiri, Thomas Koop, and Yinon Rudich. "Size-dependent ice nucleation by airborne particles during dust events in the eastern Mediterranean." Atmospheric Chemistry and Physics 19, no. 17 (September 3, 2019): 11143–58. http://dx.doi.org/10.5194/acp-19-11143-2019.
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Abstract. The prediction of cloud ice formation in climate models remains a challenge, partly due to the complexity of ice-related processes. Mineral dust is a prominent aerosol in the troposphere and is an important contributor to ice nucleation in mixed-phase clouds, as dust can initiate ice heterogeneously at relatively low supercooling conditions. We characterized the ice nucleation properties of size-segregated mineral dust sampled during dust events in the eastern Mediterranean. The sampling site allowed us to compare the properties of airborne dust from several sources with diverse mineralogy that passed over different atmospheric paths. We focused on particles with six size classes determined by the Micro-Orifice Uniform Deposit Impactor (MOUDI) cutoff sizes: 5.6, 3.2, 1.8, 1.0, 0.6 and 0.3 µm. Ice nucleation experiments were conducted in the Weizmann Supercooled Droplets Observation on a Microarray (WISDOM) setup, whereby the particles are immersed in nanoliter droplets using a microfluidics technique. We observed that the activity of airborne particles depended on their size class; supermicron and submicron particles had different activities, possibly due to different composition. The concentrations of ice-nucleating particles and the density of active sites (ns) increased with the particle size and particle concentration. The supermicron particles in different dust events showed similar activity, which may indicate that freezing was dominated by common mineralogical components. Combining recent data of airborne mineral dust, we show that current predictions, which are based on surface-sampled natural dust or standard mineral dust, overestimate the activity of airborne dust, especially for the submicron class. Therefore, we suggest including information on particle size in order to increase the accuracy of ice formation modeling and thus weather and climate predictions.
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Kuznetsov, D. V., and A. N. Pavlenko. "Intensification of heat transfer during pool boiling of nitrogen on surfaces with capillary-porous coatings produced by 3D-printing." Journal of Physics: Conference Series 2039, no. 1 (October 1, 2021): 012013. http://dx.doi.org/10.1088/1742-6596/2039/1/012013.
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Abstract The study of heat transfer, critical heat fluxes (CHF) and evaporation dynamics at pool boiling of nitrogen at atmospheric and low pressures in a stationary heat generation regimes was performed. The two flat cooper heaters with porous coatings of various structural parameters obtained by additive 3D-printing as well as smooth one were used as working surfaces. According to obtained results such coatings significantly effect on pool boiling increasing up to six times the heat transfer coefficients (HTC) in comparison with uncoated sample. For all investigated heaters and pressures, visualization of boiling was performed using a video camera from which data on the bubble departure diameters and estimates of the active nucleation site density were obtained.
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Sun, Yunkai, and Giovanni Zangari. "Streamlined Derivations and Explanations of the Scharifker-Hills Model." ECS Meeting Abstracts MA2022-01, no. 23 (July 7, 2022): 1204. http://dx.doi.org/10.1149/ma2022-01231204mtgabs.
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Despite being very popular in the analysis of experimentally measured potentiostatic transients during the initial stage of electrodeposition of metallic single-element coatings, the derivations and the assumptions of the Scharifker-Hills (S-H) model are not well understood. Important details and assumptions are scattered in different original papers. Meanwhile, some of the simplifications in derivations are somewhat intuitive, rather than being rigorously derived from a set of governing equations. It is important to understand the derivations, the assumptions, and the successfulness of the S-H model first before moving forward to an advanced model for the potentiostatic transient at the initial stage of metal or alloy electrodeposition. In this presentation, we will provide rigorous derivation for each step and each assumption, thus achieving a complete demonstration of the physics of the S-H model. References: [1] G.J. Hills, D.J. Schiffrin, J. Thompson, Electrochemical nucleation from molten salts—I. Diffusion controlled electrodeposition of silver from alkali molten nitrates, Electrochim. Acta, 19 (1974) 657-670. [2] B. Scharifker, G. Hills, Theoretical and experimental studies of multiple nucleation, Electrochim. Acta, 28 (1983) 879-889. [3] G. Gunawardena, G. Hills, I. Montenegro, B. Scharifker, Electrochemical nucleation: Part I. General considerations, J. Electroanal. Chem., 138 (1982) 225-239. [4] B.R. Scharifker, J. Mostany, Three-dimensional nucleation with diffusion controlled growth: Part I. Number density of active sites and nucleation rates per site, J. Electroanal. Chem., 177 (1984) 13-23. [5] B.R. Scharifker, J. Mostany, Electrochemical Nucleation and Growth, in: A.J. Bard (Ed.) Encyclopedia of Electrochemistry2007, pp. 512-539. [6] M. Sluyters-Rehbach, J.H.O.J. Wijenberg, E. Bosco, J.H. Sluyters, The theory of chronoamperometry for the investigation of electrocrystallization: Mathematical description and analysis in the case of diffusion-controlled growth, J. Electroanal. Chem., 236 (1987) 1-20.
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Hiranuma, N., M. Paukert, I. Steinke, K. Zhang, G. Kulkarni, C. Hoose, M. Schnaiter, H. Saathoff, and O. Möhler. "A comprehensive parameterization of heterogeneous ice nucleation of dust surrogate: laboratory study with hematite particles and its application to atmospheric models." Atmospheric Chemistry and Physics 14, no. 23 (December 10, 2014): 13145–58. http://dx.doi.org/10.5194/acp-14-13145-2014.
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Abstract. A new heterogeneous ice nucleation parameterization that covers a wide temperature range (−36 to −78 °C) is presented. Developing and testing such an ice nucleation parameterization, which is constrained through identical experimental conditions, is important to accurately simulate the ice nucleation processes in cirrus clouds. The ice nucleation active surface-site density (ns) of hematite particles, used as a proxy for atmospheric dust particles, were derived from AIDA (Aerosol Interaction and Dynamics in the Atmosphere) cloud chamber measurements under water subsaturated conditions. These conditions were achieved by continuously changing the temperature (T) and relative humidity with respect to ice (RHice) in the chamber. Our measurements showed several different pathways to nucleate ice depending on T and RHice conditions. For instance, almost T-independent freezing was observed at −60 °C < T < −50 °C, where RHice explicitly controlled ice nucleation efficiency, while both T and RHice played roles in other two T regimes: −78 °C < T < −60 °C and −50 °C < T < −36 °C. More specifically, observations at T lower than −60 °C revealed that higher RHice was necessary to maintain a constant ns, whereas T may have played a significant role in ice nucleation at T higher than −50 °C. We implemented the new hematite-derived ns parameterization, which agrees well with previous AIDA measurements of desert dust, into two conceptual cloud models to investigate their sensitivity to the new parameterization in comparison to existing ice nucleation schemes for simulating cirrus cloud properties. Our results show that the new AIDA-based parameterization leads to an order of magnitude higher ice crystal concentrations and to an inhibition of homogeneous nucleation in lower-temperature regions. Our cloud simulation results suggest that atmospheric dust particles that form ice nuclei at lower temperatures, below −36 °C, can potentially have a stronger influence on cloud properties, such as cloud longevity and initiation, compared to previous parameterizations.
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Stojanovic, Andrijana, Srdjan Belosevic, Nenad Crnomarkovic, Ivan Tomanovic, and Aleksandar Milicevic. "Nucleate pool boiling heat transfer: Review of models and bubble dynamics parameters." Thermal Science, no. 00 (2021): 69. http://dx.doi.org/10.2298/tsci200111069s.
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Understanding nucleate pool boiling heat transfer and, in particular the accurate prediction of conditions that can lead to critical heat flux, is of the utmost importance in many industries. Due to the safety issues related to the nuclear power plants, and for the efficient operation of many heat transfer units including fossil fuel boilers, fusion reactors, electronic chips, etc., it is important to understand this kind of heat transfer. In this paper, a comprehensive review of analytical and numerical work on nucleate pool boiling heat transfer is presented. In order to understand this phenomenon, existing studies on boiling heat transfer coefficient and boiling heat flux are also discussed, as well as characteristics of boiling phenomena such as bubble departure diameter, bubble departure frequency, active nucleation site density, bubble waiting and growth period and their impact on pool boiling heat transfer.
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Saunders, R. W., O. Möhler, M. Schnaiter, S. Benz, R. Wagner, H. Saathoff, P. J. Connolly, et al. "An aerosol chamber investigation of the heterogeneous ice nucleating potential of refractory nanoparticles." Atmospheric Chemistry and Physics Discussions 9, no. 6 (November 2, 2009): 23271–318. http://dx.doi.org/10.5194/acpd-9-23271-2009.
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Abstract. Nanoparticles of iron oxide (crystalline and amorphous), silicon oxide and magnesium oxide were investigated for their propensity to nucleate ice over the temperature range 180–250 K, using the AIDA chamber in Karlsruhe, Germany. All samples were observed to initiate ice formation via the deposition mode at threshold ice super-saturations (RHi thresh) ranging from 105% to 140% for temperatures below 220 K. Approximately 10% of amorphous Fe2O3 particles (modal diameter = 30 nm) generated in situ from a photochemical aerosol reactor, led to ice nucleation at RHi thresh = 140% at an initial chamber temperature of 182 K. Quantitative analysis using a singular hypothesis treatment provided a fitted function [ns (190 K) = 10(3.33×sice)+8.16] for the variation in ice-active surface site density (ns: m−2) with ice saturation (sice) for Fe2O3 nanoparticles. This was implemented in an aerosol-cloud model to determine a predicted deposition (mass accommodation) coefficient for water vapour on ice of 0.1 at temperatures appropriate for the upper atmosphere. Classical nucleation theory was used to determine representative contact angles (θ) for the different particle compositions. For the in situ generated Fe2O3 particles, a slight inverse temperature dependence was observed with θ = 10.5° at 182 K, decreasing to 9.0° at 200 K (compared with 10.2° and 11.4°, respectively for the SiO2 and MgO particle samples at the higher temperature). These observations indicate that such refractory nanoparticles are relatively efficient materials for the nucleation of ice under the conditions studied in the chamber which correspond to cirrus cloud formation in the upper troposphere. The results also show that Fe2O3 particles do not act as ice nuclei under conditions pertinent for tropospheric mixed phase clouds, which necessarily form above ~233 K. At the lower temperatures (<150 K) where noctilucent clouds form during summer months in the high latitude mesosphere, higher contact angles would be expected, which may reduce the effectiveness of these particles as ice nuclei in this part of the atmosphere.