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The three-dimensional (3D) model of cigarette was accurately constructed through reverse engineering as the research object of numerical simulation. The combustion process of cigarette was studied with computational fluid dynamics (CFD). Standard Laminar models with species transport approach were applied, and numerical simulation of the cigarette was analyzed with semi-implicit method for pressure–velocity coupling. The results showed that the model could predict velocity of cigarette smoke, the distributions of temperature and pressure at different times. In order to verify the correctness of model, it was found that the relationship between the velocity of smoke and pressure according to Darcy's law on z position (x = 4 mm, y = 0, 0 mm ≤ z ≤ 50.61 mm).

Hornification are usually occurred in cellulosic fibers and even in nanocellulose fibrils during dehydration process but their mesoscopic structural changes is not fully understood. Here we investigated the structural features of cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNF) with different solid content. In order to avoid the effect of drying, liquid AFM mode was carried out in this work. The different water contents of nanocellulose were quantified by Differential Scanning Calorimetry (DSC). We showed evidence of extreme growth in radial direction in the redispersed nanocelluloses, analyzed by statistics of contours from microscopy images. The amount of free water, freezing bound water, and non-freezing bound water decreased gradually during water evaporation and were completely removed in sequence. In addition, the hydroxyl accessibility of both redispersed CNCs and CNF were reduced by 83.33% and 81.96% via evaluating the uptake of fluorescent dyes.

In this work, we report a new characterization method using fluorescent cellulose nanofibrils to analyze retention and loss rates in the papermaking process. Cellulose nanofibrils (CNF) were isolated from chemical pulp by enzymatic pretreatment and used as a strengthening additive in sheet forming. The aim of this paper was to investigate its effects on flocculation, retention and loss rate and the physical and mechanical properties. CNF was subjected to fluorescent labeling with RBITC (Rhodamine B isothiocyanate), and the retention of fluorescent cellulose nanofibrils (FCNF) was analyzed by elemental analysis and fluorescence intensity. The retention and loss rate of the FCNF decreased with increasing the addition of FCNF. Laser Confocal Scanning Microscopy (LCSM) and Scanning Electron Microscope (SEM) images confirmed that FCNF can be evenly distributed in the paper. A thorough investigation of the relation between the retention rate and papersheet performance was conducted.