scholarly journals A Study on Sebum Hardening Effect of ZnO Powder

2021 ◽  
Vol 59 (3) ◽  
pp. 195-200
Author(s):  
Yong Min Jeon ◽  
Jin Gu Kwon ◽  
Si Hong Ryu ◽  
Yeong Cheol Lee ◽  
Seong Eui Lee
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Sodium Hydroxide ◽  
Synthesis Method ◽  
Test Method ◽  
Process Conditions ◽  
Uv Absorber ◽  
Zinc Oxide Powder ◽  
Gelling Time ◽  
Zno Powder

Zinc oxide is transparent inorganic UV absorber and widely used as a sunscreen. But sunscreen on the skin is easily erased by sebum, so zinc oxide with a sebum curing function was studied. In this study, a zinc oxide powder was prepared using zinc chloride and sodium hydroxide via a hydrothermal synthesis method. The process conditions including reaction temperature and sodium hydroxide ratio were determined. Particle size was determined using XRD and SEM, and process tendencies were checked using the gelling test method. When the sodium hydroxide ratio was lower than 58.7 wt%, the gelling time was reduced, and when the temperature was lower than 60 <sup>o</sup>, the gelling time decreased. ZnO and Simonkolleite confirmed that the gelling time was reduced when the mixture comes out.

A self-propagating high-temperature synthesis method for synthesis of zinc oxide powder

2009 ◽  
Vol 467 (1-2) ◽  
pp. 514-523 ◽  
Author(s):  
Chyi-Ching Hwang ◽  
Cheng-Shiung Lin ◽  
Gaw-Pying Wang ◽  
Cheng-Hsiung Peng ◽  
Shyan-Lung Chung
Keyword(s):  
Zinc Oxide ◽  
High Temperature ◽  
Synthesis Method ◽  
Oxide Powder ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Zinc Oxide Powder

Stability of Zinc Oxide Nanofluids Prepared with Aggregated Nanocrystalline Powders

2008 ◽  
Vol 8 (12) ◽  
pp. 6361-6366
Author(s):  
J. P. Leonard ◽  
S. J. Chung ◽  
I. Nettleship ◽  
Y. Soong ◽  
D. V. Martello ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Zinc Oxide ◽  
Brownian Motion ◽  
Preparation Method ◽  
Volume Fraction ◽  
High Volume ◽  
Nanocrystalline Powders ◽  
Zno Powder ◽  
20 Nm

Aqueous zinc oxide (ZnO) suspensions were prepared using a two-step preparation method in which an aggregated nanocrystalline ZnO powder was dispersed in water using a polyelectrolyte. The fluid showed anomalously high thermal conductivity when compared with the Maxwell and Hamilton-Crosser predictions. However, analysis of the particle size distribution showed that the fluid contained aggregated 20 nm crystallites of ZnO with a high volume fraction of particles larger than 100 nm. Sedimentation experiments revealed that particles settled out of the stationary fluid over times ranging from 0.1 hours to well over 10,000 hours. The size of the particles remaining in suspension agreed well with predictions made using Stoke's law, suggesting flocculation was not occurring in the fluids. Finally, a new concept of nanofluid stability is introduced based on the height of the fluid, sedimentation, Brownian motion and the kinetic energy of the particles.

Study on the Chemical Modification Process of Jute Fiber

TAPPI Journal ◽  
2010 ◽  
Vol 9 (2) ◽  
pp. 23-29 ◽  
Author(s):  
Wei-ming Wang ◽  
Zai-sheng Cai ◽  
Jian-yong Yu
Keyword(s):  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Treatment Time ◽  
Jute Fiber ◽  
Process Conditions ◽  
Silicate Concentration ◽  
Sodium Hydroxide Concentration ◽  
Liquor Ratio ◽  
Degumming Process ◽  
Selection Of

Degumming of pre-chlorite treated jute fiber was studied in this paper. The effects of sodium hydroxide concentration, treatment time, temperature, sodium silicate concentration, fiber-to-liquor ratio, penetrating agent TF-107B concentration, and degumming agent TF-125A concentration were the process conditions examined. With respect to gum decomposition, fineness and mechanical properties, sodium hydroxide concentration, sodium silicate concentration, and treatment time were found to be the most important parameters. An orthogonal L9(34) experiment designed to optimize the conditions for degumming resulted in the selection of the following procedure: sodium hydroxide of 12g/L, sodium silicate of 3g/L, TF-107B of 2g/L, TF-125A of 2g/L, treatment time of 105 min, temperature of 100°C and fiber to liquor ratio of 1:20. The effect of the above degumming process on the removal of impurities was also examined and the results showed that degumming was an effective method for removing impurities, especially hemicellulose.

Positive Role of Synthesis Method and Hard Template on the Catalytic Performance of SAPO-34 in Methanol to Olefin Reaction.

2020 ◽  
Vol 23 ◽  
Author(s):  
Sajjad Rimaz ◽  
Reza Katal
Keyword(s):  
Particle Size ◽  
Synthesis Method ◽  
Catalytic Performance ◽  
Hard Template ◽  
Structure Directing Agent ◽  
Positive Role ◽  
Methanol To Olefin ◽  
Dg Method ◽  
Synthesis Procedure

: In the present study, SAPO-34 particles were synthesized using hydrothermal (HT) and dry gel (DG) conversion methods in the presence of diethyl amine (DEA) as an organic structure directing agent (SDA). Carbon nanotubes (CNT) were used as hard template in the synthesis procedure to introduce transport pores into the structures of the synthesized samples. The synthesized samples were characterized with different methods to reveal effects of synthesis method and using hard template on their structure and catalytic performance in methanol to olefin reaction (MTO). DG conversion method results in smaller particle size in comparison with hydrothermal method, resulting in enhancing catalytic performance. On the other side, using CNT in the synthesis procedure with DG method results in more reduction in particle size and formation of hierarchical structure which drastically improves catalytic performance.

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