Papers by Keyword: Laser Particle Size Analyzer

Abstract: This article will present using chemical reduction to prepare silver nano-particles, which is a certain improvement base on the traditional hydrogen peroxide (H₂O₂) Silver ammonia by using a new reductant urea peroxide (CO (NH₂) ₂•H₂O₂) to replace hydrogen peroxide. Hydrogen Peroxide silver ammonia is widely used in the nano-silver particles Preparation, however, the nano-silver particles prepared in traditional ways is not homogeneous and very easy agglomerated, therefore, in this experimental by using of urea peroxide as a reductant, under condition of temperature 30°C, 45 nm homogeneous nano-silver particles is successfully prepared. The detection instrument used in the experimental is transmission electron microscopy and laser particle size analyzer.

Abstract: Polymerization effluents (PME) from dry-spun acrylic fiber manufacturing are hard to degrade. This paper evaluated the distribution characteristics of PME pollutants by means of multi scale membrane filtrations, including microfiltration (5 μm and 1 μm), ultrafiltration (50 KD, 10 KD and 6 KD), nanofiltration and reverse osmosis. Scanning electron microscopy (SEM) and laser particle size analyzer (LPSA) tests were also used as assistant measurements. The majority of particles in PME are mainly categorized as supracolloidal structures. 70% of them rage from 5 μm to 20 μm with a median size of 9.99 μm. Particulate, colloidal and soluble portions contribute 7.6%, 8.2% and 75.2% to the initial COD, meaning that the soluble fraction, which is also poor in biodegradability, plays a key role in PME treatment. 26.8% of TN, mainly consisting of various acrylonitrile copolymers, exists in the colloidal portion; while 70.5% of it, mainly comprised of ammonia, cyanide and nitrile, distributes in the soluble portion. The distribution characteristics of ammonia and SO₃^2- are similar. Respectively 92.7% and 94.7% distributes in the soluble portion.

Abstract: Cavitation erosion is predominant in pipelines for liquid transportation, causing damage to pipe wall, impeller and their accessories. The present study is focused on development of cavitation -wear resistant nano-ceramic particle-reinforced polymer matrix material; and on study of its feasibility to be used as lining material in hydraulic transportation. The polymer/nano composite is fabricated using power ultrasound in all three process steps: synthesis of nano-dimensional particles of white fused alumina (WFA) from micron size particles, optimized blending and finally reinforcement into poly methyl methacrylate (PMMA) matrix. The effect of ultrasonic parameters on nanocomposite/ virgin polymers (like polyethylene and polypropylene) is studied by measuring mass loss of the materials and suspension turbidity during exposure time. At low frequency (20-60 kHz), cavitation intensity is predominant; this effect is utilized for fabricating sub-micron particles, and for performing accelerated cavitation erosion tests. At high frequency, acoustic streaming is predominant; this effect is utilized for blending and reinforcing of the nano ceramic particles into polymer matrix. The size and quantity of the particles generated by cavitation erosion was analyzed by Laser Particle Size Analyzer (20 nm-1400 micron range). The nano-composite coupons were analyzed before and after the ultrasonic erosion test using SEM. It is concluded that lowfrequency sonication is a viable option for cavitaton erosion testing of ceramic/polymer composites.