Induction of foaming in vacuum drying by needle stimulation and the impact of solution viscosity, vapor pressure, and the type of solute and solvent

2021 ◽  
pp. 1-13
Akiho Fujioka ◽  
Rina Yamamoto ◽  
Olivier Tramis ◽  
Hiroaki Ishida ◽  
Tsutomu Ono ◽  
Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 691
Yugang Zhao ◽  
Zichao Zuo ◽  
Haibo Tang ◽  
Xin Zhang

Icing/snowing/frosting is ubiquitous in nature and industrial processes, and the accretion of ice mostly leads to catastrophic consequences. The existing understanding of icing is still limited, particularly for aircraft icing, where direct observation of the freezing dynamics is inaccessible. In this work, we investigate experimentally the impact and freezing of a water drop onto the supercooled substrate at extremely low vapor pressure, to mimic an aircraft passing through clouds at a relatively high altitude, engendering icing upon collisions with pendant drops. Special attention is focused on the ice coverage induced by an impinging drop, from the perimeter pointing outward along the radial direction. We observed two freezing regimes: (I) spread-recoil-freeze at the substrate temperature of Ts = −15.4 ± 0.2 °C and (II) spread (incomplete)-freeze at the substrate temperature of Ts = −22.1 ± 0.2 °C. The ice coverage is approximately one order of magnitude larger than the frozen drop itself, and counterintuitively, larger supercooling yields smaller ice coverage in the range of interest. We attribute the variation of ice coverage to the kinetics of vapor diffusion in the two regimes. This fundamental understanding benefits the design of new anti-icing technologies for aircraft.

2012 ◽  
Vol 602-604 ◽  
pp. 2267-2272
Shu Lei Zhao ◽  
Zheng Yuan Wei ◽  
Xiao Tian Ding ◽  
Qiang Lin

This paper experimentally examined the impact of four different drying methods (free drying, press drying, vacuum drying and impingement drying) on paper physical properties including roughness, elongation, air permeance, tearing resistance, tensile index and bursting strength. The handsheets materials are HWBKP (Hardwood Bleached Chemical Pulp), SWBKP (Softwood Bleached Chemical Pulp), CTMP (Chemical Thermo mechanical Pulp) and ATMP (Advanced Thermo Mechanical Pulp). Good experimental data were obtained for the four pulps under different drying conditions. The results of our investigation indicate that press drying have lower surface roughness, elongation and air permeance but higher tearing resistance; the vacuum drying have higher roughness, tensile index and bursting strength; the impingement drying have lower tearing resistance, tensile index and bursting strength but higher elongation and air permeance. Selection of different drying conditions for effective productivity and quality improvement potential is proposed as a direction for the future dryer design.

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1805 ◽  
Sabina Lachowicz ◽  
Anna Michalska-Ciechanowska ◽  
Jan Oszmiański

The objective of this study was to examine the effect of inulin and maltodextrin applied during vacuum drying of Saskatoon berry fruit, juice, and pomace on the retention of bioactive compounds and antioxidant capacity (radical scavenging capacity (ABTS), ferric reducing antioxidant potential (FRAP)) of powders obtained. Ultra-high performance liquid chromatography (UPLC-PDA-ESI-MS/MS) was used to identify major groups of polyphenolic compounds, such as: flavan-3-ols (35% of all polyphenols for fruit powder, 33% for juice powder, and 39% for pomace powders of all polyphenols), anthocyanins (26% for fruit powder, 5% for juice powder, and 34% for pomace), phenolic acids (33% for fruit powder, 55% for juice powder, and 20% for pomace powder), and flavanols (6% for fruit powder, 6% for juice powder, and 7% for pomace powder). In general, the content of polyphenols was more dependent on the content than on the type of carrier used for drying, regardless of the matrix tested. The average sum of polyphenols and the antioxidant activity (for ABTS and FRAP assay) of the powders with 30% of carrier addition were 5054.2 mg/100 g dry matter (d.m.) as well as 5.3 and 3.6 mmol Trolox/100 g d.m. in the ABTS and FRAP tests, respectively. The increase in carrier concentration by 20% caused a decrease of 1.5-fold in the content of polyphenols and a 1.6-fold and 1.5-fold in the antioxidant potential, regardless of the matrix tested. The principal component analysis (PCA) analysis indicated that the freeze-drying process led to the lowest degradation of the identified compounds, regardless of the matrix tested, with the exception of juice and pomace powders dried by vacuum drying at 60 °C. In this case, the release of (−)-epicatechin was observed, causing an increase in the flavanol contents. Thus, this work demonstrated the effect of processing and matrix composition on the preservation of antioxidant bioactives in Saskatoon berry powders. Properly designed high-quality Saskatoon berry powders with the mentioned carriers may be used as nutraceutical additives to fortify food products and to improve their functional properties.

2020 ◽  
Vincent Humphrey ◽  
Alexis Berg ◽  
Philippe Ciais ◽  
Christian Frankenberg ◽  
Pierre Gentine ◽  

<p>Obtaining reliable estimates of the sensitivity of carbon fluxes to water availability, temperature and vapor pressure deficit is essential for constraining climate-carbon feedbacks in Earth system models. However, these variables often co-vary because of soil moisture – atmosphere feedbacks, especially in situations where they are most susceptible to strongly impact ecosystems (e.g. during droughts and heatwaves), leading to potentially conflicting results when sensitivities are assessed independently. In particular, there is conflicting evidence on the role of temperature versus water availability in explaining these variations at the global scale.</p><p>Here, we show that accounting for the effect of soil moisture – atmosphere coupling resolves much of this controversy. Using idealized climate model experiments, we find that variability in soil moisture accounts for 90% of the inter-annual variability in land carbon uptake, mainly through its impact on photosynthesis. Without SM variability, the inter-annual variability (IAV) of land carbon uptake is almost eliminated. We show that the effects of soil moisture can be decomposed into 1) a direct ecosystem response to soil water stress and 2) a dominant indirect response to extreme temperature and vapor pressure deficit triggered by land-atmosphere coupling and controlled by anomalous soil moisture conditions.  Importantly, these two mechanisms do not necessarily have the same spatial extent, and some regions can be more sensitive to indirect effects than to direct effects.</p><p>These two pathways explain why results from coupled climate models suggest a dominant role of soil moisture, while uncoupled simulations diagnose a strong temperature effect. These findings have strong implications for offline model sensitivity analyses as well as field scale manipulation experiments (i.e. rainfall exclusion studies) where the impact of drought on carbon exchange and vegetation activity is often studied by intervening solely on soil moisture content with little consideration of the physical feedbacks on temperature and air humidity occurring in natural conditions.</p>

2007 ◽  
Vol 353-358 ◽  
pp. 2940-2943
Xu Chen ◽  
Shu Feng Zhao ◽  
Linda Zhai

Structural model of plastic electronic package under temperature and humidity is constructed, and the coupling of the thermal and moisture impact on structure field is implemented. The impact of thermal expansion, hygro-swelling and vapor pressure increases with increasing initial defect, especially the impact of vapor pressure. At certain crack length, KI and KII induced by thermal expansion is proportional to temperature difference, and KI and KII induced by vapor is proportional to vapor pressure. The impacts of thermal expansion and hygro-swelling on ERR decrease during crack propagation, but the impact of vapor pressure increases significantly.

2012 ◽  
Vol 624 ◽  
pp. 80-83
Feng Rui Zhai ◽  
Yi Ming Liu ◽  
Jian Ping Yuan ◽  
Hong Wei Zhang ◽  
Zhong Zhou Yi

It has many advantages with liquid phase reduction method to prepare the nano-silver, such as experimental conditions are simple, low cost, energy-saving, etc.. At the same time, the nano silver powder prepared by this method has high surface activity, catalytic property and wide usage. In this paper, nano-silver powder was prepared by changing the amount of protective agents with chemical liquid phase reduction method. This paper focuses on the impact of the amount of protective agent on the nano-silver. In addition, we also analyzed the reaction temperature, PH value of solution, viscosity and electrical conductivity on the preparation of nano-silver. Finally, test results from the TEM shows that the nano-silver was prepared with smaller size, uniform size and good dispersion.

2019 ◽  
Vol 12 (2) ◽  
pp. 112-117
Shahad Mahdi Saeed ◽  
Husham AL.Tameemi

An assessment was made for the impact resulted by the addition of (DO) and (DOA) on the octane number and Reid vapor pressure (RVP) of gasoline with different chemical compositions. The locally produced gasoline had been blended with three different ratios (v/v) of the additives, i.e. 8, 10 and 15%. The octane rating of gasoline was observed to continuous increased and linearly with the addition of (DO and DOA). The DOA-gasoline blends produced higher octane number. The two additives observed that decreased significantly the RVP and CV of the original fractions when blended with gasoline. However, additives were add in (8, 10, 15%vol) to gasoline blend, increasing RON was (0.9-23.9).

2010 ◽  
Vol 10 (23) ◽  
pp. 11753-11767 ◽  
V. Soonsin ◽  
A. A. Zardini ◽  
C. Marcolli ◽  
A. Zuend ◽  
U. K. Krieger

Abstract. We present vapor pressure data of the C2 to C5 dicarboxylic acids deduced from measured evaporation rates of single levitated particles as both, aqueous droplets and solid crystals. The data of aqueous solution particles over a wide concentration range allow us to directly calculate activities of the dicarboxylic acids and comparison of these activities with parameterizations reported in the literature. The data of the pure liquid state acids, i.e. the dicarboxylic acids in their supercooled melt state, exhibit no even-odd alternation in vapor pressure, while the acids in the solid form do. This observation is consistent with the known solubilities of the acids and our measured vapor pressures of the supercooled melt. Thus, the gas/particle partitioning of the different dicarboxylic acids in the atmosphere depends strongly on the physical state of the aerosol phase, the difference being largest for the even acids. Our results show also that, in general, measurements of vapor pressures of solid dicarboxylic acids may be compromised by the presence of polymorphic forms, crystalline structures with a high defect number, and/or solvent inclusions in the solid material, yielding a higher vapor pressure than the one of the thermodynamically stable crystalline form at the same temperature.

2004 ◽  
Vol 127 (3) ◽  
pp. 262-267 ◽  
X. J. Fan ◽  
J. Zhou ◽  
G. Q. Zhang ◽  
L. J. Ernst

A complete vapor pressure model based on a micromechanics approach is developed in this paper. The model can be extended to calculate the initial vapor pressure as traction loading subjected to the interfaces after the delamination. The impact of the vapor pressure induced expanison on the material’s deformation is discussed.

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