•The influence of cutting conditions on tool wear was considered through feature normalization.•Attention mechanism was used to enhance useful information and weaken redundant information.•A parallel ...CNN structure with different layers was designed to extract multiple features.•A novel tool condition prediction model based on the dense residual neural network was proposed.
In modern manufacturing industry, tool wear monitoring plays a significant role in ensuring product quality and machining efficiency. Numerous data-driven models based on deep learning have been developed to improve the accuracy of tool wear monitoring. However, tool wear monitoring under variable working conditions is rarely investigated. More importantly, for data-driven smart manufacturing, it is more meaningful and challenging to simultaneously achieve tool wear monitoring and multi-step prediction. To address the aforementioned issue, a novel framework based on feature normalization, attention mechanism, and deep learning algorithms was proposed for tool wear monitoring and multi-step prediction. Feature normalization was introduced to eliminate the dependence of local features on cutting conditions, and the attention mechanism was applied to enhance valuable information and weaken redundant information. Then a parallel convolutional neural network (parallel CNN) structure with different layers followed by Bi-directional long short term memory (BiLSTM) was developed for tool condition monitoring. Finally, based on the monitored tool wear values, a new tool condition prediction model based on the dense residual neural network (ResNetD) was proposed for short-term and long-term prediction of tool wear. Tool wear experiments under different combinations of cutting parameters were conducted to verify the proposed model, and the results showed that the proposed model has great advantages in efficiency and robustness compared with other data-driven models.
Indoor airborne microplastics fibers (MPFs) are emerging contaminants of growing concern. Nowadays, air conditioners (ACs) are widely used in indoor environments. However, little is known about their ...impact on the distribution of indoor MPFs. In this study, we first disclosed the prevalence of MPF contamination in filters for indoor split ACs used in living rooms, dormitories, and offices. The average density of microfibers was 1.47–21.4 × 102 items/cm2, and a total 27.7–35.0% of fibers were MPFs. Of these fibers, the majority were polyester (45.3%), rayon (27.8%), and cellophane (20.1%). We further tracked the long-term accumulation of MPFs on AC filters in three types of rooms, and demonstrated that dormitories showed relatively heavy accumulation especially after running for 35–42 days. Furthermore, we found that simulative AC filters which had been lined with PET MPFs could effectively release those MPFs into indoor air, propelling them away from the ACs at varying distances. Statistical analysis showed that the estimated daily intake of MPFs (5–5000 μm length) from AC filters would increase gradually with their usage, with the intake volume reaching up to 11.2 ± 2.2–44.0 ± 8.9 items/kg-BW/day by the 70th day, although this number varied among people of different ages. Altogether, these findings suggest that AC filters can act as both a sink and a source of microplastics fibers. Therefore, AC filters should be evaluated not only for their substantial impact on the distribution of indoor airborne MPFs, but also for their role in the prevalence of the related health risks.
Display omitted
•Microplastic fibers (MPFs) were widely detected on AC filters in multiple types of room.•MPFs including polyester, rayon and cellophane account for 28–35% fibers on AC filters.•MPFs accumulate on AC filters gradually, heavily after usage of 35–42 days.•Simulative PET MPFs can effectively release from AC filters, and into indoor air.•Estimated daily intake of MPFs increase with AC usage, vary among different age people.
Display omitted
•LNP can be mixed with CNF, PVA and borax to assemble self-healable hydrogel.•CNF acted as reinforcing agents to enhance the interaction between polymer matrix.•LNP acted as ...nano-spacers to impede aggregation between hydrophilic materials.•Tuning LNP content can be an effective way to tailor the hydrogel property.
To face the increasing demand of self-healing hydrogels with high performance for various applications ranging from bioscaffolds, culture matrices to responsive electronic devices, lignin nanoparticle-containing composite hydrogels are assembled via dynamic reversible didiol-borax linkages and linear polyvinyl alcohol (PVA) and cellulose nanofibrils (CNF). Lignin nanoparticles (LNP) acted as nano-spacers to fill the three-dimensional network, leading to enhanced viscoelasticity and thermal stability of hydrogel. With the increased LNP content, composite hydrogel exhibited the highest storage modulus and loss modulus of 8504 Pa and 3260 Pa, respectively, 28 times and 18 times greater than pure hydrogel without LNP. The resulting hydrogel showed porous network structure and excellent recovery behavior under continuous step strain. In general, this work demonstrates a facile approach to transfer nanoscale building blocks to 3D polymeric materials with tunable dynamic rheology properties and may provide a new prospect for the rational design of functional hydrogels for applications that require high rheological property.
Herein, lignocellulosic nanofibrils (LCNF) suspension containing 0.1, 3.9, and 17.2 wt% lignin were utilized to fabricate films by filtration and pressing process. The stiff nature of fibrils ...containing lignin made them less able to conform during filtration, resulting in more uneven surface structure with higher roughness value. Lignin in the films interfered in hydrogen bonding between cellulose nanofibrils, thus impairing mechanical property of the film, such as tensile stress and Young’s modulus. Due to the presence of chromophore groups, lignin absorbed light and the light transmittance of film was decreased. However, the film containing lignin displayed unusually high hydrophobicity with water contact angle of 88° and maximal weight loss temperature (
T
max
) of 372 °C. Overall, this study provides useful knowledge for understanding the result of lignin on the formation, surface morphology and physical behavior of LCNF films, especially in related bioproducts that requires low hydrophilicity, high roughness and high thermal stability.
Display omitted
•Lignosulfonate (LS) was an excellent dispersant for hexagonal boron nitride (h-BN) since its phenolic hydroxyl groups and three-dimensional structure.•Three-dimensional thermally ...conductive pathways were well built and optimized when the h-BN/cellulose nanofiber (CNF) ratio was 3:1 (w/w).•The through-plane thermal conductivity of LS-BN/CNF/polyvinyl alcohol (PVA) composite was high up to 1.22 W/mK.•This LS-BN/CNF/PVA composite held great practical potentials in thermal interface materials as a key building block.
Hexagonal boron nitride (h-BN) is an excellent thermally conductive and electrically insulative material. However, the formation of heat transfer pathways of h-BN in thermal interface materials is restricted due to its poor aqueous dispersity. Herein, water-soluble lignosulfonate (LS) is used to promote the dispersion of h-BN, the phenolic hydroxyl and three-dimensional structure of LS could form hydrogen bonding or steric hindrance with h-BN under ultrasound treatment. After mixing with cellulose nanofiber (CNF), the three-dimensional thermally conductive pathways are built in LS-BN/CNF aerogel through freeze-drying. The results show that the through-plane thermal conductivity of LS-BN/CNF/PVA composite with 0.2 wt% LS (LS0.2-BN/CNF/PVA) exceeds 1.22 W/mK when the h-BN/CNF ratio is 3:1 (w/w), which is 6.1-fold of that of PVA film (0.20 W/mK). The initial decomposition temperature and tensile strength of LS0.2-BN/CNF/PVA composite are 205 °C and 38.5 MPa, respectively, demonstrating acceptable thermal stability and mechanical properties for electronics as thermal interface and packing material. Overall, this work put forwards an effective approach to disperse h-BN and paves the way in developing high-performance thermal interface materials.
Glutathione transferases (GSTs), the ancient, ubiquitous and multi-functional proteins, play significant roles in development, metabolism as well as abiotic and biotic stress responses in plants. ...Wheat is one of the most important crops, but the functions of GST genes in wheat were less studied.
A total of 330 TaGST genes were identified from the wheat genome and named according to the nomenclature of rice and Arabidopsis GST genes. They were classified into eight classes based on the phylogenetic relationship among wheat, rice, and Arabidopsis, and their gene structure and conserved motif were similar in the same phylogenetic class. The 43 and 171 gene pairs were identified as tandem and segmental duplication genes respectively, and the Ka/Ks ratios of tandem and segmental duplication TaGST genes were less than 1 except segmental duplication gene pair TaGSTU24/TaGSTU154. The 59 TaGST genes were identified to have syntenic relationships with 28 OsGST genes. The expression profiling involved in 15 tissues and biotic and abiotic stresses suggested the different expression and response patterns of the TaGST genes. Furthermore, the qRT-PCR data showed that GST could response to abiotic stresses and hormones extensively in wheat.
In this study, a large GST family with 330 members was identified from the wheat genome. Duplication events containing tandem and segmental duplication contributed to the expansion of TaGST family, and duplication genes might undergo extensive purifying selection. The expression profiling and cis-elements in promoter region of 330 TaGST genes implied their roles in growth and development as well as adaption to stressful environments. The qRT-PCR data of 14 TaGST genes revealed that they could respond to different abiotic stresses and hormones, especially salt stress and abscisic acid. In conclusion, this study contributed to the further functional analysis of GST genes family in wheat.
The clogging of submerged entry nozzles is a critical issue during continuous casting that adversely affects final product quality and process productivity. In order to impose effective monitoring ...and control over the continuous casting process, a quantitative index was formulated to quantify the magnitude of SEN clogging and erosion for a production dataset consisting of ultra-low carbon, low carbon, medium carbon, and calcium treated grades. Three critical index values are defined to represent the clogging event, erosion event, and critical casting condition. Long short-term memory network was established based on the quantitative index in the past four minutes to predict that in the future 48 seconds. The networks are found to be capable of predicting the overall trend in quantitative index, with the lowest normalized root mean squared error at 0.323 for medium carbon grade, followed by that at 0.340, 0.342, and 0.453 for low carbon, calcium-treated carbon, and ultra-low carbon grades respectively. The models can also identify most of the critical casting conditions and erosion incidents for all steel grades. Operators can take corresponding actions when critical conditions are predicted by the models in order to prevent the possible occurrence of clogging. Model precision could be improved with larger production datasets that consist of multiple number of clogging and erosion events.
•Wheat MYB gene TaMyb1D was cloned.•The expression levels of TaMyb1D was induced under PEG and H2O2 treatments.•TaMyb1D regulated phenylpropanoid metabolism and affected plant development.•TaMyb1D ...enhanced drought and oxidative stress tolerance in transgenic tobacco plants.
MYB transcription factors are involved in the regulation of plant development and response to biotic and abiotic stress. In this study, TaMyb1D, a novel subgroup 4 gene of the R2R3-MYB subfamily, was cloned from wheat (Triticum aestivum L.). TaMyb1D was localized in the nucleus and functioned as a transcriptional repressor. The overexpression of TaMyb1D in tobacco (Nicotiana tabacum) plants repressed the expression of genes related to phenylpropanoid metabolism and down-regulated the accumulation of lignin in stems and flavonoids in leaves. These changes affected plant development under normal conditions. The expression of TaMyb1D was ubiquitous and up-regulated by PEG6000 and H2O2 treatments in wheat. TaMyb1D-overexpressing transgenic tobacco plants exhibited higher relative water content and lower water loss rate during drought stress, as well as higher chlorophyll content in leaves during oxidative stress. The transgenic plants showed a lower leakage of ions as well as reduced malondialdehyde and H2O2 levels during conditions of drought and oxidative stresses. In addition, TaMyb1D up-regulated the expression levels of ROS- and stress-related genes in response to drought stress. Therefore, the overexpression of TaMyb1D enhanced tolerance to drought and oxidative stresses in tobacco plants. Our study demonstrates that TaMyb1D functions as a negative regulator of phenylpropanoid metabolism and a positive regulator of plant tolerance to drought and oxidative stresses.
Practical production of conductive paper requires the balancing of high electrical conductance, thermal stability and tensile modulus, with cost effectiveness. By utilizing lignocellulose (3.85 ± ...0.35% and 17.17 ± 0.62% lignin contents) and graphite as starting materials, a lignocellulose/reduced graphene oxide (LRGO) composite conductive paper is successfully fabricated. The free-standing LRGO paper has a low sheet resistance of 506 ± 34 Ω/sq with a graphene derivative content of ~ 20 wt%. Also high T
onset
(312 °C) and T
95
(251 °C) are observed, along with a tensile modulus up to 8.36 GPa if ten additional passes of microfluidization are used. Moreover, LRGO paper was used to make active electrodes for a supercapacitor that achieved a specific capacitance of 77.0 F/g. There has been minimal reporting of applying lignocellulose in conductive paper production, so this new method is anticipated to pave the way for developing advanced materials derived from low cost biomass.
Graphical abstract
Solid acids have been proposed as a hydrolytic agent for wood biomass dissolution. In this work, we presented an environmentally friendly physicochemical treatment to leave behind cellulose, dissolve ...hemicellulose, and remove lignin from poplar wood. Several pretreatments, such as autohydrolysis and disk refining, were compared to optimize and modify the process. The
-toluenesulfonic acid could extract lignin from wood with a small amount of cellulose degradation. Disk refining with subsequent acid hydrolysis (so-called physicochemical treatment) doubled the delignification efficiency. A comprehensive morphology and overall chemical composition were provided. The crystallinity index (CrI) of treated poplar was increased and the chemical structure was changed after physicochemical treatment. Optical microscopy and scanning electron microscopy analysis demonstrated physicochemical treatment affected the morphology of poplar wood by removing lignin and generating fiberization. In general, this work demonstrated this physicochemical method could be a promising fractionation technology for lignocellulosic biomass due to its advantages, such as good selectivity, in removing lignin while preserving cellulose.
PDF
