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The preparation and application of non-isocyanate polyurethane (NIPU) from biomass raw materials as a substitute for traditional polyurethane (PU) has recently become a research hot topic as it avoids the toxicity and moisture sensitivity of isocyanate-based PU. In the work presented here, self-blowing GNIPU non-isocyanate polyurethane (NIPU) rigid foams were prepared at room temperature, based on glucose, with acids as catalysts and glutaraldehyde as a cross-linker. The effects of different acids and glutaraldehyde addition on foam morphology and properties were investigated. The water absorption, compressive resistance, fire resistance, and limiting oxygen index (LOI) were tested to evaluate the relevant properties of the foams, and scanning electron microscopy (SEM) was used to observe the foams' cell structure. The results show that all these foams have a similar apparent density, while their 24 h water absorption is different. The foam prepared with phosphoric acid as a catalyst presented a better compressive strength compared to the other types prepared with different catalysts when above 65% compression. It also presents the best fire resistance with an LOI value of 24.3% (great than 22%), indicating that it possesses a good level of flame retardancy. Thermogravimetric analysis also showed that phosphoric acid catalysis slightly improved the GNIPU foams' thermal stability. This is mainly due to the flame-retardant effect of the phosphate ion. In addition, scanning electron microscopy (SEM) results showed that all the GNIPU foams exhibited similar open-cell morphologies with the cell pore sizes mainly distributed in the 200–250 μm range. [ABSTRACT FROM AUTHOR]

Tannin foam is a new functional material. It can be widely applied to the automobile industry, construction industry, and packaging industry due to its wide range of raw materials, renewable, easily degraded, low cost and almost no pollution. Preparing tannin foam is a very complex process that includes high temperature, two phases, mechanical agitation, and phase change. To investigate the influence of the stirring velocity and paddle shape, simulation was calculated by making use of the volume of fluid (VOF) method and multiple reference frame (MRF) method in a three-dimensional flow field of tannin-based foaming precursor resin. The gas holdup and velocity magnitude were analysed with various conditions of mechanical velocities and paddle shape in the stirring flow field. The result shows the higher the velocity, the greater the disturbance and paddle shape between the eggbeater and the Rushton turbine, obviously the paddle shape of the eggbeater with a wider range of agitation, which can entrap more air into the tannin-based foaming precursor resin in a short time. Especially when the speed is 1500 rpm, the flow field of the Rushton turbine comes out of a ditch, which decreases the efficiency of mass transfer; there is less air to mix into the tannin-based foaming precursor resin, which causes unevenness. At the same time, the eggbeater shows the marvelous capability of hybrid as it has two vortexes and multiple cycles that make a difference from the Rushton turbine, which has only one vortex and two upper and lower loops; the structure makes the flow field more stable allowed evenness of flow field tannin-based foaming precursor resin. The results reveal that it is beneficial for tannin-based foaming precursor resin to use an eggbeater with a speed of 1500 rpm to reduce the consumption of resources while obtaining a uniform flow field. [ABSTRACT FROM AUTHOR]

A nonparametric process monitoring scheme with Variable Sampling Intervals (VSI) is investigated to monitor the median in this paper. The proposed scheme is based on the sign test statistic and used a new adaptive-type exponentially weighted moving average control chart. A discrete-state Markov Chain method is presented, and the exact Average Time to Signal (ATS) properties are discussed. The comparative results indicate that the proposed chart can reduce the time in detecting shifts than the corresponding schemes for the fixed sampling interval and provide higher sensitivity for detecting shifts with various magnitudes. The proposed chart's in-control robustness is demonstrated for different continuous distributions using numerical results based on the Monte-Carlo simulation. The implementation of this VSI nonparametric chart is also explained through an illustrative example. [ABSTRACT FROM AUTHOR]

Plasma treatment of wood surfaces has shown significant effects, but different excitation methods used for different species of wood generally result in varied characteristics of wood surfaces. Secondly, plasma modification greatly enhances the absorption of liquids by wood, but the relationship between liquid absorption and surface wettability is rarely studied. Limited detailed investigation of the modification effects and mechanisms has hindered the large-scale applications of plasma treatment in the wood industry. In this study, two typical plasmas, radio frequency (RF) plasma and gliding arc discharge (GAD) plasma, were employed to treat three species of wood: poplar, black walnut, and sapele. By focusing on changes in the contact angle of the wood surface, an exponential equation fitting method is used to determine the measurement time for contact angles. The research identified that factors contributing to the decrease in contact angle after plasma modification include not only the increase in surface energy but also liquid absorption. SEM and XPS analyses demonstrate that plasma etching accelerated liquid absorption by modifying the surface topography, while the increase in surface energy was due to the addition of oxygen-containing groups. High-valence C=O and O-C=O groups serve as indicators of plasma-induced surface chemical reactions. RF modification primarily features surface etching, whereas GAD significantly increases the active surface groups. Thus, different plasmas, due to their distinct excitation modes, produce diverse modification effects on wood. Considering the various physical and chemical properties of plasma-modified wood surfaces, recommendations for adhesive use on plasma-modified wood are provided. [ABSTRACT FROM AUTHOR]

Soybean meal (SM) adhesive is widely acknowledged as a viable substitute for traditional formaldehyde-based adhesives, given its ability to be easily modified, the utilization of renewable sources, and its eco-friendly characteristics. However, the application of SM adhesive in manufacturing has been impeded due to its restricted bonding capacity and inadequate water resistance. Researchers in the wood industry have recognized the significance of creating an SM-based adhesive, which possesses remarkable adhesive strength and resistance to water. This study endeavors to tackle the issue of inadequate water resistance in SM adhesives. Sodium lignosulfonate (L) was oxidized using hydrogen peroxide (HP) to oxidized lignin (OL) with a quinone structure. OL was then used as a modifier, being blended with SM to prepare SM-based biomass (OLS) adhesives with good water resistance, which was found practically through its utilization in the production of plywood. The influence of the HP dosage and OL addition on plywood properties was examined. The changes in the lignin structure before and after oxidation were confirmed using gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The curing behavior and thermal stability of OLS adhesives were analyzed using dynamic mechanical analysis (DMA) and thermogravimetric (TG) analysis. The reaction mechanism was also investigated using FT-IR and XPS. The outcomes indicated a decrease in the molecular weight of L after oxidation using HP, and, at the same time, quinone and aldehyde functionalized structures were produced. As a result of the reaction between the quinone and aldehyde groups in OL with the amino groups in SM, a dense network structure formed, enhancing the water resistance of the adhesive significantly. The adhesive displayed exceptional resistance to water when the HP dosage was set at 10% of L and the OL addition was 10% based on the mass of SM. These specific conditions led to a notable enhancement in the wet bonding strength (63 °C, 3 h) of the plywood prepared using the adhesive, reaching 0.88 ± 0.14 MPa. This value represents a remarkable 125.6% increase when compared to the pure SM adhesive (0.39 ± 0.02 MPa). The findings from this study introduce a novel approach for developing adhesives that exhibit exceptional water resistance. [ABSTRACT FROM AUTHOR]

In the response surface based RPD, the optimal setting of the controllable factor is highly dependent on the accuracy of the response surface. Classically, in order to improve the accuracy of the response surface, it is necessary to add more samples. The larger the number of samples, the higher the accuracy. Traditional RPD usually uses a one-shot modeling method to construct a response surface. Whenever the number of samples increases, all samples need to be learned from the beginning to rebuild the response surface. However, The one-shot modeling method significantly increases the time of model training and the complexity of model training. We present an incremental strategy to build response models. Our solution is based on the Huber-support vector regression machine. In this article, the incremental Huber-SVR model is proposed to construct the response surface in robust parameter design. The proposed algorithm can continuously integrate new sample information into the already built model. In incremental HSVR-RPD, we can use the optimal settings of the previous controllable factors, the currently observed noise factor and the corresponding response to improve the accuracy of the response surface, so as to obtain more reliable recommended settings in the next stage. [ABSTRACT FROM AUTHOR]

Developing bio-based plastic has become an important strategy for solving environmental pollution. In this study, konjac flour (KF) and poly-vinyl alcohol (PVA) as main film-forming substances with added citric acid (CA), glutaraldehyde (GA) and glycerin, were used to prepare bio-based composite films via solution casting. How the PVA polymer amount affected the composite films including mechanical performance, structural properties and morphology was investigated. The results revealed that PVA polymer could obviously improve the mechanical property of the films, and the addition of 25% PVA based on KF mass when CA, GA and glycerin were fixed, was demonstrated as the optimal amount, maintaining an excellent tensile strength (TB) and elongation at break (EAB). Fourier transform infrared spectra (FT-IR) and X-ray diffraction (XRD) results indicated the successful cross-linking reaction between PVA and KF, and some further proofs could be confirmed from scanning electron microscopy (SEM) and thermogravimetry (TG). After modification with PVA, the cross section of the KF/PVA composite film was more dense and uniform, implying that PVA was well fused with KF system. Meanwhile, the films modified with PVA presented a good thermal resistance ability. This work provided an effective pathway for preparing KF/PVA composite films with improved mechanical properties, which may be an alternative way for using konjac flour. [ABSTRACT FROM AUTHOR]

The coefficient of variation (CV) is one of the most important quality characteristics in industrial applications. There have been some control charts for monitoring this dimensionless and normalized characteristic. This paper presents three double exponentially weighted moving average (DEWMA) charts for monitoring the CV. Many numerical simulations are performed and the results are given in several tables to show the properties of the proposed DEWMA CV charts. Through comparisons with other existing exponentially weighted moving average (EWMA) CV charts using the average run length (ARL) metric, it is shown that the proposed DEWMA CV charts perform better than the existing EWMA CV charts for small shifts, especially when the smoothing parameter increases. In addition, a detailed comparison among the proposed three DEWMA CV charts is also presented. A real date example from industry is used to show the implementation of the proposed charts. [ABSTRACT FROM AUTHOR]