Effects of Forming Temperature on Structure and Chemical Properties of Calcium Phosphate Cement

2014 ◽  
Vol 910 ◽  
pp. 149-152
Author(s):  
Ching Wen Lou ◽  
Yung Yu Chang ◽  
Ming Chun Sie ◽  
Wen Cheng Chen ◽  
Jia Horng Lin

With similar components to human bone, hydroxyapatite (HAp) has been commonly used in dental and orthopedics practice. Calcium phosphate cement (CPC) can be made into porous HAp scaffolds through reaction; therefore, this study aims to examine how reaction temperatures influence CPC. CPC powder and NaCl are blended, and after diammonium phosphate (DAP) is added, they are infused into a mold for a hydration reaction under a saturated vapor pressure to form CPC scaffolds. XRD and FTIR are used to determine the influence of reaction temperatures on crystallization and functional groups. A scanning electron microscope (SEM) observes the structures of the CPC scaffolds. Test results show that when the temperature of a saturated vapor pressure is 70 °C, the CPC scaffolds have significant crystalline conversion and functional group peaks. SEM observation indicates that the temperature of a saturated vapor pressure does not affect the formation of the CPC scaffolds structure.

Author(s):  
Zaihua Fan ◽  
Ruixiang Wang ◽  
Mingqiang Zheng

The mineral nano-CuO refrigeration oil had been prepared. Saturated vapor pressure of pure HFC134a and three kinds of mixtures of HFC134a separately with pure mineral refrigeration oil, mineral nano-CuO refrigeration oil and POE refrigeration oil had been measured by using a set of high-precision fluid thermo-physical properties measurement system. The test results show that the relative deviation of the saturated vapor pressure of the HFC134a ranged from −0.02% to 0.70%, when mixed with 7.7%(w/w) nano-CuO refrigeration oil, and the average deviation was 0.33%; when 7.7% POE was mixed, relative deviation varied from 0.10% to −2.20%,and the average, 1.38%.


2021 ◽  
Vol 11 (3) ◽  
pp. 1273
Author(s):  
Chen Feng ◽  
Jiping Zhou ◽  
Xiaodong Xu ◽  
Yani Jiang ◽  
Hongcan Shi ◽  
...  

In recent years, 3D printing has received increasing attention from researchers. This technology overcomes the limitations of traditional technologies by printing precise and personalized scaffold with arbitrary shapes, pore structures, and porosities for the applications in various tissues. The cellulose nanocrystal (CNC) is extracted from Humulus Japonicus (HJS) and mixed with poly(ε-caprolactone) (PCL) to prepare a series of CNC/PCL composites for printing. Based on the analysis of the physical and chemical properties of the series of the CNC/PCL composites, an optimal mass ratio of CNC to PCL was obtained. The Solidworks was used to simulate the stretching and compression process of the scaffolds with three different patterns under an external force. The flow of nutrient solution in the scaffolds with different patterns was simulated by ANSYS FLUENT, and then a new optimization scaffold pattern with a concave hexagon shape was advised based on the simulation results. Collectively, the mechanical test results of the material and scaffold confirmed that the optimal filling amount of the CNC was 5%, and the scaffold pattern with concave hexagon shape exhibited better mechanical properties and suitable for the transport of cells and nutrients, which is expected to be more widely used in 3D printing.


2018 ◽  
Vol 240 ◽  
pp. 03004
Author(s):  
Min-rui Chen ◽  
Jin-yuan Qian ◽  
Zan Wu ◽  
Chen Yang ◽  
Zhi-jiang Jin ◽  
...  

When liquids flowing through a throttling element, such as a perforated plate, the velocity increases and the pressure decreases. If the pressure is below the saturated vapor pressure, the liquid will vaporize into small bubbles, which is called hydraulic cavitation. In fact, vaporization nucleus is another crucial condition for vaporizing. The nanoparticles contained in the nanofluids play a significant role in vaporization of liquids. In this paper, the effects of the nanoparticles on hydraulic cavitation are investigated. Firstly, a geometric model of a pipe channel equipped with a perforated plate is established. Then with different nanoparticle volume fractions and diameters, the nanofluids flowing through the channel is numerically simulated based on a validated numerical method. The operation conditions, such as the temperature and the pressure ratio of inlet to outlet, are the considered variables. As a significant parameter, cavitation numbers under different operation conditions are achieved to investigate the effects of nanoparticles on hydraulic cavitation. Meanwhile, the contours are extracted to research the distribution of bubbles for further investigation. This study is of interests for researchers working on hydraulic cavitation or nanofluids.


2005 ◽  
Vol 284-286 ◽  
pp. 353-356 ◽  
Author(s):  
Koji Ioku ◽  
Giichiro Kawachi ◽  
Nakamichi Yamasaki ◽  
Hirotaka Fujimori ◽  
Seishi Goto

Porous plates of hydroxyapatite (Ca10(PO4)6(OH)2; HA) with about 0.5 to 5 mm in thickness and porous HA granules of about 40 µm to 1 mm in size with tailored crystal surface were prepared by the hydrothermal vapor exposure method at the temperatures above 105 °C under saturated vapor pressure of pure water. Porous HA plates with about 75 % porosity prepared at 120 °C were composed of rod-shaped crystals of about 20 µm in length. Porous HA granules prepared at 160 °C were also composed of rod-shaped crystals of about 20 µm in length with the mean aspect ratio of 30. These crystals were elongated along the c-axis. Rod-shaped HA crystals were locked together to make micro-pores of about 0.1 to 0.5 µm in size. Both of materials were nonstoichiometric HA with calcium deficient composition. These materials must have the advantage of adsorptive activity, because they had large specific crystal surface and much micro-pores.


Daxue Huaxue ◽  
2021 ◽  
Vol 0 (0) ◽  
pp. 2107062-0
Author(s):  
Shuai Zhang ◽  
Jian Zhang ◽  
Shaowei Bian ◽  
Yaping Zhao ◽  
Li Shen ◽  
...  

The effect of Nano charcoal ash (NCA) from coconut shell on the physical and chemical properties of bitumen as alternative binder was evaluated in this study. Six different Nano grades of charcoal ash were examined. The charcoal ash ground for the optimum grinding time had a median particle size of 148 nm. NCA dosage of 30% by weight of binder was used throughout the experiments. Nanoparticle size analysis and X-ray fluorescence were performed to determine the size and chemical properties of material. Dynamic shear rheometer, penetration, softening point, and penetration index were used to characterize the physical properties of NCA. Thirty hours of grinding time produced the optimum NCA, which could enhance the binder performance. Test results indicated that adding NCA from coconut shell to bitumen improved the binder stiffness up to 47% and significantly increased the softening point up to 12% compared with virgin binder.


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