PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 7, Number 2, 2021
times, with the standout being the reduction from LRC 10K1P at 84 min to R-LRC 10K1P at 1.14 min of drainage time. The combination of high sheet strength and sharply reduced drainage times provide a rare example of the recycled product being superior to the original product. TESTING “ Research on determination of total ash and its components of paper by continuous X-ray method ” , Lianhua Hu & Xinyu Lu, Chemical Papers (2021). The X-ray diffraction internal standard method can quantitatively determine the ash content of paper, but the requirements for the experimental environment are high, the determination is not convenient and the cost is high, and it is difficult to be widely used in the papermaking enterprises. In order to determine the total ash and its components of the single filler paper samples, and meet the ash determination requirements of papermaking enterprises, the continuous X-ray method is proposed. In this paper, an X-ray tube is used as the radiation source and an ionization chamber is used as the detector. Through polynomial fitting of the total ash and voltage logarithm ratio of the single filler paper samples, the mathematical model of total ash is established; the total ash and its components content of paper are calculated according to the mathematical model of total ash and the Beer – Lambert law deformation formula; the total ash and its components content of paper are verified by the burning method. The research results show that the total ash error of the single filler paper samples is less than 4%, and the ash component error is less than 5%. “ Liquid droplet imbibition into a thin coating layer: Direct pore-scale modeling and experimental observations ” , H. Aslannejad, S.V. Loginov, B. van der Hoek, E.M. Schoonderwoerd, H.C. Gerritsen and S.M. Hassanizadeh, Progress in Organic Coatings , Vol.151, February 2021. In order to control ink droplet movement into the printing-paper layer, a set of pore-scale two-phase flow simulations were performed. The high-resolution three-dimensional pore space of the paper was obtained using focused ion beam scanning electron microscopy (FIB-SEM). Solving Navier-Stokes equations yielded details about dynamic movement of a droplet into the layer. To evaluate simulation results, for the first time, confocal laser microscopy imaging technique was integrated into a FIB- SEM chamber. Doing so, high resolution imaging of the droplet penetration inside paper was conducted and computed volume of penetrated ink at final stage was compared to the imaged volume. The ink penetration and spreading extent showed a good agreement with simulation results. Therefore, the developed simulation case was further investigated to study impact of liquid contact angle, real ink properties, and droplet arrival velocity on paper surface on final print quality. A faster penetration into the paper coating was observed for smaller equilibrium contact angles; meanwhile, more radial wicking was observed. In case of velocity of impact, higher velocity caused creation of irregular shapes of the ink footprint on paper surface. In addition to that, higher velocity caused ink splash which consequently created satellite droplets and lowered the print quality. Comparing ink- like liquid (representing real ink liquid properties) with water, water moves faster than ink- like liquid into the paper. This is mainly due to the higher viscosity and lower surface tension of the ink-like liquid. “ Correlation between Dusting Gauge Method and Paper Quality Values”, Elina Asikainen, Tampere University of Applied Sciences, Bachelor's thesis, June 2021, Dusting of paper can be caused by different factors and can occur in many ways. This makes the measuring of the dusting tendency challenging. One method developed is Emerson’s Dusting Gauge, which can be used to take dusting samples of paper on a paper machine. Emerson s method does not give standards for dust results. Those must
Technical Abstracts
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