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Hui Zhang - One of the best experts on this subject based on the ideXlab platform.
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experimental study on moisture migration of unsaturated loess during the Freezing Process
Advances in Civil Engineering, 2020Co-Authors: Hui Zhang, Tiehang Wang, Enlong LiuAbstract:To reveal the water-heat transfer mechanism of unsaturated loess, the effects of soil dry density (1.30 g/cm3, 1.50 g/cm3, and 1.65 g/cm3), moisture content (13.3%, 16.2%, and 19.4%), cold end temperature (−7°C, −10°C, and −13°C), and Freezing mode on moisture migration in unsaturated loess in this paper are studied through indoor tests of moisture migration under the Freezing action of large-size unsaturated loess. The results show that the temperature change in soil samples in the Freezing Process can be divided into three stages: rapid cooling stage, slow cooling stage, and stable stage. The higher the dry density, the closer the Freezing front is to the cold end, with the initial moisture content having little effect on the Freezing front, while the temperature at the cold end has a significant effect on the location of the Freezing front. The total amount of moisture migration decreases with the increase of dry density, increases with the increase of moisture content, and increases with the decrease of cold end temperature. The Freezing mode directly affects the distribution of moisture content and total amount of moisture migration in the frozen area.
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Axisymmetric lattice Boltzmann model for simulating the Freezing Process of a sessile water droplet with volume change.
Physical Review E, 2020Co-Authors: Chaoyang Zhang, Hui Zhang, Wen-zhen Fang, Yugang Zhao, Chun YangAbstract:Droplet Freezing not only is of fundamental interest but also plays an important role in numerous natural and industrial Processes. However, it is challenging to numerically simulate the droplet Freezing Process due to its involving a complex three-phase system with dynamic phase change and heat transfer. Here we propose an axisymmetric lattice Boltzmann (LB) model to simulate the Freezing Process of a sessile water droplet with consideration of droplet volume expansion. Combined with the multiphase flow LB model and the enthalpy thermal LB model, our proposed approach is applied to simulate the sessile water droplet Freezing on both hydrophilic and hydrophobic surfaces at a fixed subcooled temperature. Through comparison with the experimental counterpart, the comparison results show that our axisymmetric LB model can satisfactorily describe such sessile droplet Freezing Processes. Moreover, we use both LB simulations and analytical models to study the effects of contact angle and volume expansion on the Freezing time and the cone shape formed on the top of frozen droplets. The analytical models are obtained based on heat transfer and geometric analyses. Additionally, we show analytically and numerically that the Freezing front-to-interface angle keeps nearly constant (smaller than 90°).
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Experimental and numerical study on the impact and Freezing Process of a water droplet on a cold surface
Applied Thermal Engineering, 2018Co-Authors: Cong Li, Rui Yang, Hui ZhangAbstract:Abstract Ice accretion on cold solid surfaces presents hazards to a broad range of applications. It is quite essential to understand the dynamic and Freezing mechanism of water droplets on a cold solid substrate for the prevention of ice accretion. In this study, the impact and Freezing Process of water droplets was studied experimentally and numerically. The effects of substrate temperature on the whole Processes were investigated through changing the surface temperature from room temperature 25 °C to −30 °C. The results showed that the decrease of surface temperature led to the decrease of retraction rate, equilibrium droplet height after oscillation, Freezing delay time and Freezing time, while increased the final contact area due to the lower viscous dissipation energy. Also, a numerical model was developed to investigate the impact and Freezing Process of water droplets on an ultra-cold surface (−100 °C to −40 °C). The predicted droplet impact morphology, dynamic characteristics (spreading factor) and the propagation of Freezing front were compared with experimental results, which exhibited good agreements. The numerical results suggested that the final contact area decreased slightly with the drastic decrease in surface temperature when the surface temperature is below −40 °C. Moreover, the influence of surface temperature on Freezing front propagation and Freezing time were analyzed in detail from the numerical results.
Emma Chiavaro - One of the best experts on this subject based on the ideXlab platform.
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Impact of the industrial Freezing Process on selected vegetables -Part II. Colour and bioactive compounds.
Food Research International, 2015Co-Authors: Teresa Mazzeo, Attilio Visconti, Tommaso Ganino, Emma Chiavaro, Maria Paciulli, Vincenzo Fogliano, Nicoletta PellegriniAbstract:Abstract In the present study, the impact of the different steps (i.e. blanching, Freezing, storage following the industrial Freezing Process and the final cooking prior to consumption) of the industrial Freezing Process was evaluated on colour, chlorophylls, lutein, polyphenols and ascorbic acid content of asparagus, green beans and zucchini. In addition, the domestic boiling of raw samples was compared with the boiling of frozen storage vegetables. Results showed that the blanching treatment retained phytochemicals in all studied green vegetables and the frozen storage up to 2 months did not negatively affected phytochemicals, in particular lutein and flavonoids in almost all samples. On the contrary, colour significantly changed during blanching and frozen storage. The changes of b* (yellowness) and the shift of H° (hue angle) were not coherent with the increase of pheophytin. In addition, the greenness (− a*) was found to increase with the exception of boiled samples in all vegetables. Generally, in boiled frozen vegetables there was a better or comparable retention of bioactive compounds with respect to raw ones, and this was especially true for green beans and zucchini. Colour changes after cooking did not exhibit the same trends among vegetables, being more remarkable for frozen asparagus in comparison with those boiled from raw, but overall comparable for green beans and zucchini. In conclusion, the overall results of the present study suggest that, when the industrial Freezing Process is well performed, the boiled frozen vegetables do not have a lower nutritional value than the fresh ones.
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Impact of the industrial Freezing Process on selected vegetables - Part I. Structure, texture and antioxidant capacity
Food Research International, 2015Co-Authors: Maria Paciulli, Maria Zaupa, Massimiliano Rinaldi, Tommaso Ganino, Andrea Fabbri, Nicoletta Pellegrini, Emma ChiavaroAbstract:In thiswork, the impact of the industrial Freezing Process on structure, texture and total antioxidant capacitywas studied using green asparagus stems, zucchini and green beans. Samples were analysed as raw/uncooked, blanched, raw/boiled and industrially frozen/boiled. A consistent damage of the vegetable tissue was revealed by the histological analysis on vegetables boiled after Freezing. The cells appeared to be dehydrated, contracted and separated at different levels depending on the anatomical structure of each vegetable. The initial textural qualitywas partially retained in all blanched vegetables, and enhanced in cut tested asparagus stems, in relation to the action of phenolic acids at cellwall level. Raw/boiled and industrially frozen/boiled asparagus stems exhibited comparable forces of penetration and cut tests. On the other hand, zucchini, both raw and frozen, completely softened after boilingmaking the texturemeasurement impossible. Industrially frozen/boiled green beans showed higher values of cut and penetration forces, probably due to a higher presence of swollen cell walls, in comparison to those raw/boiled. Blanching and boiling significantly increased the ferric reducing antioxidant power values of asparagus stems and green beans compared to uncooked/raw samples, while boiling after the Freezing Process significantly deprived both vegetables of the initial antioxidant capacity. On the other hand, boiling the frozen zucchini proved to be detrimental to the antioxidant capacity. In conclusion, manufacturers and researchers should join together to develop specific industrial Freezing Process conditions according to the matrix of each vegetable.
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Impact of the industrial Freezing Process on selected vegetables — Part I. Structure, texture and antioxidant capacity
Food Research International, 2014Co-Authors: Maria Paciulli, Maria Zaupa, Massimiliano Rinaldi, Tommaso Ganino, Andrea Fabbri, Nicoletta Pellegrini, Emma ChiavaroAbstract:Abstract In this work, the impact of the industrial Freezing Process on structure, texture and total antioxidant capacity was studied using green asparagus stems, zucchini and green beans. Samples were analysed as raw/uncooked, blanched, raw/boiled and industrially frozen/boiled. A consistent damage of the vegetable tissue was revealed by the histological analysis on vegetables boiled after Freezing. The cells appeared to be dehydrated, contracted and separated at different levels depending on the anatomical structure of each vegetable. The initial textural quality was partially retained in all blanched vegetables, and enhanced in cut tested asparagus stems, in relation to the action of phenolic acids at cell wall level. Raw/boiled and industrially frozen/boiled asparagus stems exhibited comparable forces of penetration and cut tests. On the other hand, zucchini, both raw and frozen, completely softened after boiling making the texture measurement impossible. Industrially frozen/boiled green beans showed higher values of cut and penetration forces, probably due to a higher presence of swollen cell walls, in comparison to those raw/boiled. Blanching and boiling significantly increased the ferric reducing antioxidant power values of asparagus stems and green beans compared to uncooked/raw samples, while boiling after the Freezing Process significantly deprived both vegetables of the initial antioxidant capacity. On the other hand, boiling the frozen zucchini proved to be detrimental to the antioxidant capacity. In conclusion, manufacturers and researchers should join together to develop specific industrial Freezing Process conditions according to the matrix of each vegetable.
Lina Cheng - One of the best experts on this subject based on the ideXlab platform.
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effects of micro nano bubbles on the nucleation and crystal growth of sucrose and maltodextrin solutions during ultrasound assisted Freezing Process
Lwt - Food Science and Technology, 2018Co-Authors: Da-wen Sun, Zhiwei Zhu, Zi Zhang, Lina ChengAbstract:Abstract The effects of micro-nano bubbles (MNBs) on the ultrasound-assisted Freezing Process of sucrose and maltodextrin solutions were investigated and different Freezing characteristics of both nucleation period and crystal growth period were analyzed. Results showed that the introduction of MNBs was effective for the acceleration of Freezing Process, including the ice nucleation and crystal growth of both sucrose and maltodextrin solutions. Under optimal combination conditions, both sucrose and maltodextrin solutions with MNBs achieved a remarkable reduction in the supercooling degree and Freezing time (Tn = −1.24 ± 0.09 °C, tp = 92 ± 3.88 s and t = 230 ± 4.82 s for sucrose solution, and Tn = −1.97 ± 0.13 °C, tp = 102.9 ± 8.62 s and t = 240.2 ± 3.72 s for maltodextrin solution) as compared with conventional immersion Freezing (Tn = −7.87 ± 4.65 °C, tp = 126 ± 17.86 s and t = 303 ± 28.12 s for sucrose solution without MNBs, and Tn = −8.24 ± 4.73 °C, tp = 127 ± 18.12 s, t = 303.83 ± 17.86 s for maltodextrin solution without MNBs). This study suggested that the introduction of MNBs was a feasible method for enhancing ultrasound-assisted Freezing Process.
Li Wang - One of the best experts on this subject based on the ideXlab platform.
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effect of contact angle on water droplet Freezing Process on a cold flat surface
Experimental Thermal and Fluid Science, 2012Co-Authors: Lingyan Huang, Zhongliang Liu, Yaomin Liu, Yujun Gou, Li WangAbstract:Abstract The effect of contact angle on water droplet Freezing Process on a cold flat surface under natural convection conditions was experimentally investigated. A series of hydrophobic surfaces with different contact angles were prepared by solution immersion. The contact angles of these surfaces were varied from 97.2° to 154.9°. Comparative observations of water droplet Freezing Processes were carried out on both plain copper surface and these hydrophobic surfaces under the same conditions. The experimental results showed that the contact angle has a strong influence on the water droplet Freezing time. The larger the contact angle is, the longer the Freezing time. The frost crystals growth on the droplet surface that frozen on the hydrophobic surface is faster and presents a pattern that is more dendritic than that on the plain copper surface.
Maria Paciulli - One of the best experts on this subject based on the ideXlab platform.
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Impact of the industrial Freezing Process on selected vegetables -Part II. Colour and bioactive compounds.
Food Research International, 2015Co-Authors: Teresa Mazzeo, Attilio Visconti, Tommaso Ganino, Emma Chiavaro, Maria Paciulli, Vincenzo Fogliano, Nicoletta PellegriniAbstract:Abstract In the present study, the impact of the different steps (i.e. blanching, Freezing, storage following the industrial Freezing Process and the final cooking prior to consumption) of the industrial Freezing Process was evaluated on colour, chlorophylls, lutein, polyphenols and ascorbic acid content of asparagus, green beans and zucchini. In addition, the domestic boiling of raw samples was compared with the boiling of frozen storage vegetables. Results showed that the blanching treatment retained phytochemicals in all studied green vegetables and the frozen storage up to 2 months did not negatively affected phytochemicals, in particular lutein and flavonoids in almost all samples. On the contrary, colour significantly changed during blanching and frozen storage. The changes of b* (yellowness) and the shift of H° (hue angle) were not coherent with the increase of pheophytin. In addition, the greenness (− a*) was found to increase with the exception of boiled samples in all vegetables. Generally, in boiled frozen vegetables there was a better or comparable retention of bioactive compounds with respect to raw ones, and this was especially true for green beans and zucchini. Colour changes after cooking did not exhibit the same trends among vegetables, being more remarkable for frozen asparagus in comparison with those boiled from raw, but overall comparable for green beans and zucchini. In conclusion, the overall results of the present study suggest that, when the industrial Freezing Process is well performed, the boiled frozen vegetables do not have a lower nutritional value than the fresh ones.
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Impact of the industrial Freezing Process on selected vegetables - Part I. Structure, texture and antioxidant capacity
Food Research International, 2015Co-Authors: Maria Paciulli, Maria Zaupa, Massimiliano Rinaldi, Tommaso Ganino, Andrea Fabbri, Nicoletta Pellegrini, Emma ChiavaroAbstract:In thiswork, the impact of the industrial Freezing Process on structure, texture and total antioxidant capacitywas studied using green asparagus stems, zucchini and green beans. Samples were analysed as raw/uncooked, blanched, raw/boiled and industrially frozen/boiled. A consistent damage of the vegetable tissue was revealed by the histological analysis on vegetables boiled after Freezing. The cells appeared to be dehydrated, contracted and separated at different levels depending on the anatomical structure of each vegetable. The initial textural qualitywas partially retained in all blanched vegetables, and enhanced in cut tested asparagus stems, in relation to the action of phenolic acids at cellwall level. Raw/boiled and industrially frozen/boiled asparagus stems exhibited comparable forces of penetration and cut tests. On the other hand, zucchini, both raw and frozen, completely softened after boilingmaking the texturemeasurement impossible. Industrially frozen/boiled green beans showed higher values of cut and penetration forces, probably due to a higher presence of swollen cell walls, in comparison to those raw/boiled. Blanching and boiling significantly increased the ferric reducing antioxidant power values of asparagus stems and green beans compared to uncooked/raw samples, while boiling after the Freezing Process significantly deprived both vegetables of the initial antioxidant capacity. On the other hand, boiling the frozen zucchini proved to be detrimental to the antioxidant capacity. In conclusion, manufacturers and researchers should join together to develop specific industrial Freezing Process conditions according to the matrix of each vegetable.
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Impact of the industrial Freezing Process on selected vegetables — Part I. Structure, texture and antioxidant capacity
Food Research International, 2014Co-Authors: Maria Paciulli, Maria Zaupa, Massimiliano Rinaldi, Tommaso Ganino, Andrea Fabbri, Nicoletta Pellegrini, Emma ChiavaroAbstract:Abstract In this work, the impact of the industrial Freezing Process on structure, texture and total antioxidant capacity was studied using green asparagus stems, zucchini and green beans. Samples were analysed as raw/uncooked, blanched, raw/boiled and industrially frozen/boiled. A consistent damage of the vegetable tissue was revealed by the histological analysis on vegetables boiled after Freezing. The cells appeared to be dehydrated, contracted and separated at different levels depending on the anatomical structure of each vegetable. The initial textural quality was partially retained in all blanched vegetables, and enhanced in cut tested asparagus stems, in relation to the action of phenolic acids at cell wall level. Raw/boiled and industrially frozen/boiled asparagus stems exhibited comparable forces of penetration and cut tests. On the other hand, zucchini, both raw and frozen, completely softened after boiling making the texture measurement impossible. Industrially frozen/boiled green beans showed higher values of cut and penetration forces, probably due to a higher presence of swollen cell walls, in comparison to those raw/boiled. Blanching and boiling significantly increased the ferric reducing antioxidant power values of asparagus stems and green beans compared to uncooked/raw samples, while boiling after the Freezing Process significantly deprived both vegetables of the initial antioxidant capacity. On the other hand, boiling the frozen zucchini proved to be detrimental to the antioxidant capacity. In conclusion, manufacturers and researchers should join together to develop specific industrial Freezing Process conditions according to the matrix of each vegetable.