Review on Applications of Lignin in Pavement Engineering: A Recent Survey

Lignin is the second-largest plant polymer on Earth after cellulose. About 98% of lignin produced in the papermaking and pulping industry is used for combustion heating or power generation. Less than 2% of lignin is used in more valuable fields, mainly in the formulation of dispersants, adhesives, and surfactants. Asphalt is one of the most important materials in pavement engineering. It is a dark brown complex mixture composed of hydrocarbons with different molecular weights and their non-metallic derivatives. Because the chemical structure of lignin is similar to that of asphalt, it is a carbon-based hydrocarbon material. More researchers studied the application of lignin in pavement engineering. In this paper, the structure, application, and extraction technology of lignin were summarized. This is a review article describing the different applications of lignin in pavement engineering and exploring the prospects of the application. There are three main types of pavement materials that can be used for lignin in pavement engineering, which are asphalt, asphalt mixture, and roadbed soil. In asphalt, lignin can be used as a modifier, extender, emulsifier, antioxidant, and coupling agent. In asphalt mixtures, lignin can be used as an additive. In road base soils, lignin can be used as a soil stabilizer. Furthermore, the article analyzed the application effects of lignin from the life cycle assessment. The conclusions suggest that lignin-modified asphalt exhibits more viscosity and hardness, and its high-temperature resistance and rutting resistance can be significantly improved compared with conventional asphalt. In addition, some lignin-modified asphalt binders exhibit reduced low-temperature crack resistance and fatigue resistance, which can be adjusted and selected according to the climate change in different regions. The performance of lignin as an asphalt mixture additive and asphalt extender has been proved to be feasible. Lignin can also produce good mechanical properties as well as environmental benefits as a soil stabilizer. In summary, lignin plays an important role in asphalt pavement and roadbed soil, and it is likely to be a development trend in the future due to its environmental friendliness and low cost. More research is needed to generalize the application of lignin in pavement engineering

Study on Effects of salt stress on the Suberin Lamella of grapevine roots

Grape is one of the oldest tree species in the world which have a relatively high tolerance to salt stress. The function of Suberin Lamella is to control the transport of water and ions, which has a positive effect on salt tolerance. However, whether the suberin lamella of grape root is related to its salt-tolerance has not been revealed. In this study, suberin lamella in roots of two grape varieties, "Crimson seedless" and "1103p", were stained by FY0888. Results showed that salt stress induced the appearance and thickening of suberin lamella of grape root cortex. The induction effect was very obvious in salt-toerant "Crimson seedless", while the effect was weak in "1103P", indicating that the suberin lamella of grape was indeed involved in the salt tolerance of grape

Different physiopsychological changes between AMSsusceptible and AMS-resistant pre-selected Antarctic expeditioners in Tibet

Through dynamically monitoring changes of acute mountain sickness (AMS) occurrences, cardiopulmonary function and mood states from Shanghai (4 m) to Lhasa (3650 m) and Yambajan (4300 m), Tibet, we obtained physiopsychological data of the 37th Chinese Antarctic pre-selected expeditioners for Kunlun Station. Through analyzing different physiopsychological changes between AMS-susceptible (AMS-S) and AMS-resistant (AMS-R) expeditioners, we would explore indicators to screen hypoxia-susceptible expeditioners. According to AMS occurrences evaluated by Lake Louise Score (LLS) in Yambajan, we divided the expeditioners (n=24, 31.92±5.76 a) into AMS-S and AMS-R groups. Using a series of medical instruments and questionnaires, we monitored their cardiopulmonary function and mood states, and analyzed the differences of physiopsychological parameters between AMS-S and AMS-R groups. Compared with Shanghai, when expeditioners arrived in Yambajan, in both AMS-S and AMS-R groups, oxygen saturation (SpO2) significantly decreased, and blood pressure significantly increased (P<0.05). As for electrocardiogram (ECG), interval from the beginning to the end of QRS complex wave (QRS), interval from the beginning of QRS complex wave to the end of T wave (QT), interval between 2 adjacent P waves (PP) and interval between 2 adjacent R waves (RR) significantly decreased, heart rate (HR) and HR-corrected QT interval (QTc) significantly increased (P<0.05). Cardiac contractility and pumping function significantly decreased, systemic vascular resistance significantly increased (P<0.05). Pulmonary airway patency significantly increased (P<0.05). Compared with AMS-R group, AMS-S group showed significantly lower SpO2 and higher stroke volume variation (SVV) in Shanghai, however, significantly lower maximal expiratory flow at 75% of forced vital capacity (MEF75), higher levels of anxiety, fatigue and confusion in Yambajan (P<0.05). In conclusion, when expeditioners arrived at 4300 m, their cardiopulmonary function and mood states changed significantly. SpO2, SVV, MEF75, anxiety, fatigue and confusion maybe could be used as clues for screening hypoxia-susceptible individuals

Modulating physical and chemical properties of biomaterials in rapid 3D printing

Understanding the physical and chemical properties of biomaterials in rapid 3D printing could pave a way for the construction of complex structures with specific functionalities. Both the material conditions and printing techniques play crucial roles in modulating these properties. This dissertation was dedicated to answering the basic questions about how to engineer and improve the mechanical performance of rapidly 3D printed structure from synthesis and printing process. Three distinct groups of materials, namely plastic, soft hydrogels, and elastomeric polymers were used as case studies to reveal their relationships. Additionally, the toughening mechanism of networks with different mechanical properties was discovered and tested. These results could help future studies in rapid prototyping of medical devices, as well as adapting 3D printing in tissue engineering as a new direction

Upper semicontinuity of uniform attractors for nonclassical diffusion equations

Abstract We study the upper semicontinuity of a uniform attractor for a nonautonomous nonclassical diffusion equation with critical nonlinearity. In particular, we prove that the uniform (with respect to (w.r.t.) g ∈ Σ $g\in \Sigma$ ) attractor A Σ ε $\mathcal {A}^{\varepsilon }_{\Sigma }$ ( ε ⩾ 0 $\varepsilon \geqslant 0$ ) for equation (1.1) satisfies lim ε → ε 0 dist H 0 1 ( Ω ) ( A Σ ε , A Σ ε 0 ) = 0 $\lim_{\varepsilon \to \varepsilon _{0}}\operatorname{dist}_{H_{0}^{1}(\Omega )}(\mathcal {A}^{\varepsilon } _{\Sigma },\mathcal {A}^{\varepsilon _{0}}_{\Sigma })=0$ for any ε 0 ⩾ 0 $\varepsilon _{0}\geqslant 0$