Papers by Keyword: Cell Density

Abstract: Cell-seeded hydrogel scaffolds have been widely used in various tissue engineering applications due to their excellent biocompatibility and biomimetic properties. One of the critical issues in successful use of hydrogel scaffolds is their mechanical properties. Since cells and hydrogels are physically different materials, the cells encapsulated in the hydrogels can change profoundly the mechanical properties of the hydrogel scaffolds. In this research, the effects of Schwann cell density on mechanical properties of alginate hydrogel scaffolds were investigated. It was found that increase of cell density decreases the strength of the scaffolds. It was also found that the Ogden model can best describe the mechanical properties of the scaffolds under the strain of 45% at varying cell densities. Based on the cell density-dependant mechanical properties, a simulation was performed to study the local stresses of on cells when cells are subjected to loading. Simulation shows that at the same strain, the stress concentration on cells decreases as the cell density increases. The experimental and simulation results obtained in this paper will allow one to rigorously design scaffolds with desired mechanical properties and provide a clue to avoid mechanical cell injury.

Abstract: The Urea SCR system is a promising approach to reduce NOx in order to meet stringent limits on Euro 1V and Euro V standards. Apart from thermodynamic properties (temperature, pressure,heat and mass transfer), the cell geometry of SCR also got significant role in reduction of NOx. The current study focuses on the calculation of NOx conversion by varying the Open Frontal area of monolith, volume of monolith, cell density thereby to choose best cell geometry which will result in maximum DeNOx efficiency. It has been found that as the cell density increases the NOx conversion efficiency also increases. In the current analysis, a cell density varying from 200 CPSI to 400 CPSI is considered. One dimensional steady state and transient kinetic analysis are carried out using AVL BOOST software. The monolith volume is varied from 0.002m³ to 0.008m³ and the effects on DeNOx efficiency are discussed. The Open frontal area of SCR catalyst also been varied, and the effects on NOx conversion is studied. It has been found that as the cell density, monolith volume increases, the NOx conversion efficiency also increases, where as it decreases with increase in Open frontal area. The results are validated through experimental results obtained from the literature.

Abstract: Formula for microcellular unsaturated polyester using chemical foaming method was studied. With the increase of NaHCO3 content, the cell size of microcellular unsaturated polyester slightly decreased with the increase of styrene content in the range of 1-2 %. The cell size increased in the range of 2-4 %. With the increase of curing agent content, the cell size increased in the range of 0.5-0.9 % and decreased in the range of 0.9-1.3 %. The cell size decreased with the increase of styrene content in the range of 30-40 %. The cell size had little variation when styrene content was in the range of 40-50 %. The average cell size and cell density of microcellular unsaturated polyester were strongly affected by accelerant content. The cell size decreased with the increase of accelerant content. The opposite was for the cell density. The microcellular unsaturated polyester prepared at 2% NaHCO3, 0.3% accelerantt, 0.9% curing agent, 40% styrene had the small cell size, high cell density, and strong compression strength.

Abstract: Microcellular unsaturated polyester was prepared by different foaming agents was studied. Compared with the cell size and density of microcellular unsaturated polyester prepared using azodicarbonamide (AC), the ones of microcellular unsaturated polyester prepared using NaHCO3 were small. For NaHCO3, the cell density of microcellular unsaturated polyester decreased with the increasing temperature. For microcellular unsaturated polyester prepared using NaHCO3 at 100 °C, the average cell size was about 18 μm and the cell density was 1.1×1010 cells/cm3. The compression strength at 100 °C is strongest among that of the materials at the other temperature. The average compression strength was 24.2 MPa. The compression strength-to-weight ratio of microcellular unsaturated polyester prepared at 90 °C and 100 °Cwas about twice that of unsaturated polyester.

Abstract: This paper verified the relationship between the cell density of three types of substrates with different cell densities (400cpsi, 600cpsi, 900cpsi) and light-off factor (LOF). The results tested on engine bench demonstrated that, higher cell density of substrate could improve the light-off performance characteristics of catalysts. The effect of increasing cell density of substrate on air-fuel ratio characteristic of catalyst. It was effective measurement that higher cell density enlarged the operating window of catalyst.

Abstract: In this paper, Pd/Rh series catalyst substrate samples were prepared at the different cell density, with different volume. The fresh catalyst aging treatment. And Catalysts test by light-off factor (LOF). The results tested demonstrated that, it can achieve equal performance levels with the cell density is 600cpsi that the catalyst sample of the cell density is 400cpsi with the precious metal content for the 1.2g/L. This is more efficient for low content of noble metal catalysts. This work is still importantly to promoted catalyst stability, that the catalyst structure is optimized. And it can be used as the interaction between cell density and noble metal content of catalysts.

Abstract: To reveal the relationship between nutrient input and red tide outbreaks, the effects of N/P atomic ratio on the specific growth rate of Alexandrium tamarense is analyzed under various initial phosphate concentrations in laboratory cultures. The results show that both the cell density and the specific growth rate of A.tamarense first increased when the N/P atomic ratio ≤ (N/P)_opt and then decreased when the N/P atomic ratio ≥ (N/P)_opt in low-P-grown cultures, followed by those in medium-P-grown and high-P-grown cultures. And the highest cell density in low-P-grown, medium-P-grown, and high-P-grown cultures is 1776×10⁴, 4094×10⁴ and 6891×10⁴ cells/L, respectively. The maximum specific growth rate is 4.022, 5.307 and 9.672 d^-1, respectively. It seems that the higher the initial phosphate concentrations, the greater the probability of red tide outbreaks.

Abstract: Formula for glass fiber/microcellular unsaturated polyester composites (GF/MCUP) using supersaturated gas technology was studied by the way of orthogonal experiment. The results showed that these factors affecting average cell size from strongly to weakly were styrene content, accelerant content, glass fiber length, curing agent and glass fiber content, respectively. The factors affecting average cell density from strongly to weakly were accelerant content, styrene content, glass fiber content, curing agent content and glass fiber length, respectively. Curing agent content was the major factor affecting impact strength of GF/MCUP. The factors revealed no obvious difference in affecting tensile strength. Under the optimizing processing condition, the average cell size of GF/MCUP was about 8 μm and the cell density was 1.19×10⁹ cells/cm³. The 153.70 and 255.84 % increase in impact strength were gained over that of GF/UP and UP, respectively. The corresponding 20.24 and 82.51% increase in tensile strength-to-weight ratio were gained over that of GF/UP and UP, respectively.

Abstract: Glass fiber/microcellular unsaturated polyester composites (GF/MCUP) were prepared using the supersaturated gas technology. Technological process included three stages. The effect of processing parameters on average cell size, cell density, impact strength and tensile strength was investigaed by orthogonal experiment. The results indicated that the major factor affecting them was the temperature in stageⅡ(T2). Under the optimizing processing condition, the average cell size of GF/MCUP was about 8 μm and the cell density was 1.57×109 cells/cm3. It was found that impact strength of GF/MCUP increased 88.81 and 188.12 % than that of glass fiber/unsaturated polyester composites (GF/UP) and unsaturated polyester plastics (UP), respectively. The corresponding 16.56 and 69.25 % increase in tensile strength-to-weight ratio were gained over that of GF/UP and UP, respectively.