Numerical Simulation of Mass Transfer and Three-Dimensional Fabrication of Tissue-Engineered Cartilages Based on Chitosan/Gelatin Hybrid Hydrogel Scaffold in a Rotating Bioreactor

2016 ◽  
Vol 181 (1) ◽  
pp. 250-266 ◽  
Author(s):  
Yanxia Zhu ◽  
Kedong Song ◽  
Siyu Jiang ◽  
Jinglian Chen ◽  
Lingzhi Tang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Three Dimensional ◽  
Hydrogel Scaffold ◽  
Hybrid Hydrogel

scholarly journals Numerical Estimation of Limiting Current Density by Focusing on Mass Transfer within Porous Spacers in an Electro-Dialysis

Membranes ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 75 ◽  
Author(s):  
Yoshihiko Sano ◽  
Kosuke Fukagawa ◽  
Fujio Kuwahara
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Current Density ◽  
Three Dimensional ◽  
Design Guidelines ◽  
Limiting Current ◽  
Safe Operation ◽  
Limiting Current Density ◽  
Flow Disturbances ◽  
Flow Stagnation

Estimating and increasing limiting current density (LCD) levels is of fundamental importance for the development of electrodialysis (ED) systems, and it is becoming clear that the use of porous spacers can significantly increase such LCD levels. In this study, a three-dimensional numerical simulation was proposed for evaluating the mass transfer within a porous spacer unit cell and for estimating LCD levels. It was found that our proposed method is effective for estimating the minimum value of an LCD, which is a significant factor related to the safe operation of ED systems. Furthermore, it was found that increasing the minimum effective Sherwood number provides a key to increasing LCD levels. Porous spacer design guidelines were proposed based on the numerical simulation results, after which a new spacer was introduced, designed according to those guidelines. It was found that flow disturbances on the membrane caused by porous spacer structures can lead to increases in effective Sherwood numbers and that LCD levels could be increased by eliminating the flow stagnation behind the structures on the membrane. The LCD of our new spacer was found to be higher than that of the spacers with the highest LCD levels in use at present. Therefore, we can conclude that the proposed design guidelines are effective for increasing LCD levels.

Numerical Study of the Thermal Performance in Natural Draft Wet Cooling Tower with Different Fill Types

2012 ◽  
Vol 562-564 ◽  
pp. 1032-1035
Author(s):  
Shui Hua Zheng ◽  
Tai Jin ◽  
Jian Ren Fan
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Thermal Performance ◽  
Cooling Tower ◽  
Numerical Study ◽  
Three Dimensional ◽  
Natural Draft ◽  
Mass Transfer Theory ◽  
Fluent Software ◽  
Fill Depth

Based on the heat and mass transfer theory and characteristics of the FLUENT software, a three-dimensional numerical simulation platform composed by user defined functions had been developed to simulate the thermal performance in a natural draft wet cooling tower. This platform was used to study a typical hyperbolic natural draft wet cooling tower with different fill types. The variations of the flow and temperature field in the cooling tower caused by the two different methods of fill were investigated. It is found that the outlet water temperature will decrease due to the non-uniform fill depth. The non-uniform fill depth is beneficial to increasing the efficiency of the cooling tower.

Three-Dimensional Numerical Study on Thermal Performance in a Natural Draft Wet Cooling Tower

2012 ◽  
Vol 614-615 ◽  
pp. 169-173
Author(s):  
Shui Hua Zheng ◽  
Tai Jin ◽  
Jian Ren Fan
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Thermal Performance ◽  
Water Distribution ◽  
Cooling Tower ◽  
Numerical Study ◽  
Three Dimensional ◽  
Cooling Efficiency ◽  
Natural Draft ◽  
Mass Transfer Theory

Based on the heat and mass transfer theory and characteristics of the CFD software, a three-dimensional numerical simulation platform had been developed to study the thermal performance in a natural draft wet cooling tower. This platform was validated using the measured results of a running cooling tower. The flow and temperature field in the cooling tower were investigated. It is found that the water temperature and flow field can be correctly calculated using this platform. The cooling efficiency could be improved due to non-uniform fill and water distribution methods.

scholarly journals Hot Spots Drift in Synchronous and Asynchronous Polars: Results of Three-Dimensional Numerical Simulation

Galaxies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 110
Author(s):  
Dmitry Bisikalo ◽  
Andrey Sobolev ◽  
Andrey Zhilkin
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Temperature Distribution ◽  
Hot Spots ◽  
Transfer Rate ◽  
Hot Spot ◽  
Mass Transfer Rate ◽  
Three Dimensional ◽  
Jet Trajectory ◽  
Dominant Influence

In this paper, the characteristics of hot spots on an accretor surface are investigated for two types of polars: the eclipsing synchronous polar V808 Aur and the non-eclipsing asynchronous polar CD Ind in configuration of an offset and non-offset magnetic dipole. The drift of hot spots is analyzed based on the results of numerical calculations and maps of the temperature distribution over the accretor surface. It is shown that a noticeable displacement of the spots is determined by the ratio of ballistic and magnetic parts of the jet trajectory. In the synchronous polar, the dominant influence on the drift of hot spots is exerted by variations in the mass transfer rate, which entail a change in the ballistic part of the trajectory. It was found that when the mass transfer rate changes within the range of 10−10M⊙/year to 10−7M⊙/year, the displacement of the hot spot in latitude and longitude can reach 30∘. In the asynchronous polar, a change in the position of hot spots is mainly defined by the properties of the white dwarf magnetosphere, and the displacement of hot spots in latitude and longitude can reach 20∘.

scholarly journals Chitosan-Hydrogel Polymeric Scaffold Acts as an Independent Primary Inducer of Osteogenic Differentiation in Human Mesenchymal Stromal Cells

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3546
Author(s):  
Simona Bernardi ◽  
Federica Re ◽  
Katia Bosio ◽  
Kamol Dey ◽  
Camillo Almici ◽  
...  
Keyword(s):  
Osteogenic Differentiation ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Three Dimensional ◽  
Digital Pcr ◽  
Hydrogel Scaffold ◽  
Hybrid Hydrogel ◽  
Human Mesenchymal Stromal Cells ◽  
Polymeric Scaffold ◽  
Significant Difference

Regenerative medicine aims to restore damaged tissues and mainly takes advantage of human mesenchymal stromal cells (hMSCs), either alone or combined with three-dimensional scaffolds. The scaffold is generally considered a support, and its contribution to hMSC proliferation and differentiation is unknown or poorly investigated. The aim of this study was to evaluate the capability of an innovative three-dimensional gelatin–chitosan hybrid hydrogel scaffold (HC) to activate the osteogenic differentiation process in hMSCs. We seeded hMSCs from adipose tissue (AT-hMSCs) and bone marrow (BM-hMSCs) in highly performing HC of varying chitosan content in the presence of growing medium (GM) or osteogenic medium (OM) combined with Fetal Bovine Serum (FBS) or human platelet lysate (hPL). We primarily evaluated the viability and the proliferation of AT-hMSCs and BM-hMSCs under different conditions. Then, in order to analyse the activation of osteogenic differentiation, the osteopontin (OPN) transcript was absolutely quantified at day 21 by digital PCR. OPN was expressed under all conditions, in both BM-hMSCs and AT-hMSCs. Cells seeded in HC cultured with OM+hPL presented the highest OPN transcript levels, as expected. Interestingly, both BM-hMSCs and AT-hMSCs cultured with GM+FBS expressed OPN. In particular, BM-hMSCs cultured with GM+FBS expressed more OPN than those cultured with GM+hPL and OM+FBS; AT-hMSCs cultured with GM+FBS presented a lower expression of OPN when compared with those cultured with GM+hPL, but no significant difference was detected when compared with AT-hMSCs cultured with OM+FBS. No OPN expression was detected in negative controls. These results show the capability of HC to primarily and independently activate osteogenic differentiation pathways in hMCSs. Therefore, these scaffolds may be considered no more as a simple support, rather than active players in the differentiative and regenerative process.

Sign in / Sign up

Export Citation Format

Share Document