LKCA: Large Kernel Convolutional Attention

We revisit the relationship between attention mechanisms and large kernel ConvNets in visual transformers and propose a new spatial attention named Large Kernel Convolutional Attention (LKCA). It simplifies the attention operation by replacing it with a single large kernel convolution. LKCA combines the advantages of convolutional neural networks and visual transformers, possessing a large receptive field, locality, and parameter sharing. We explained the superiority of LKCA from both convolution and attention perspectives, providing equivalent code implementations for each view. Experiments confirm that LKCA implemented from both the convolutional and attention perspectives exhibit equivalent performance. We extensively experimented with the LKCA variant of ViT in both classification and segmentation tasks. The experiments demonstrated that LKCA exhibits competitive performance in visual tasks. Our code will be made publicly available at https://github.com/CatworldLee/LKCA

Experimental Research on Creep Characteristics of Nansha Soft Soil

A series of tests were performed to investigate the creep characteristics of soil in interactive marine and terrestrial deposit of Pearl River Delta. The secondary consolidation test results show that the influence of consolidation pressure on coefficient of secondary consolidation is conditional, which is decided by the consolidation state. The ratio of coefficient of secondary consolidation and coefficient of compressibility Ca/Cc is almost a constant, and the value is 0.03. In the shear-box test, the direct sheer creep failure of soil is mainly controlled by shear stress rather than the accumulation of shear strain. The triaxial creep features are closely associated with the drainage conditions, and consolidation can weaken the effect of creep. When the soft soil has triaxial creep damage, the strain rate will increase sharply

An Investigation of Time-Dependent Deformation Characteristics of Soft Dredger Fill

The creep characteristics of soft clays have been studied for decades. However, the lateral deformation of soils is not allowed during the commonly used one-dimensional consolidation tests, which cannot describe the real deformation features of soils in practice. On the other hand, the influence of drainage distance on the mechanical properties of soil is still controversial, classified as hypothesis A and hypothesis B. For a better understanding of deformation characteristics of soft clay, especially which in long-terms, a series of conventional oedometer tests as well as novel geometric confined consolidation tests was conducted on soft dredger fill. The results show that the secondary consolidation coefficient of the soil sample Cα would increase firstly, followed by a small decrease with the increase of consolidation pressure generally. Cα would decrease with the consolidation time and also be reduced by preloading. The strain at the completion of primary consolidation would increase with the drainage distance, but the Cα would be affected little. Both compression index Cc and Cα of soft clay would reduce after preconsolidation, in which two parameters show an approximate linear relationship. The creep coefficient of soft clay under the geometric confinement Cαε k is larger than that under the oedometer test Cαε. However, the trends of the relationship between the creep coefficient and loading are consistent regardless of the confinement conditions

Exploring the effect of different typical plant community on human stress reduction: a field experiment

Abstract Research has demonstrated the positive effect of natural environment on human restoration and well-being. Time spent in nature can often alleviate both physiological and psychological stress. However, few studies have discussed the environmental health effects of the nature’s components and characteristics. Sixty volunteers were recruited and one manufactured environment and five different natural environments were randomly assigned to them, including coniferous forests (pure coniferous forest-PC and mixed coniferous forest-MC), broad-leaved forests (pure broad-leaved forest-PB and mixed broad-leaved forest-MB), and mixed forest (mixed coniferous and broad-leaved forest-MCB). Each volunteer sat in a built or natural environment and looked around the environment for 15 min. Physiological (HR, HRV, BP, pulse rate and salivary cortisol) and psychological indicators (POMS and STAI) were used to evaluate the changes in their stress level. Results indicated a strong difference in HR, HRV, POMS and STAI between the built and natural environment, which showed that natural environment can lower the stress level. MC had the best effect on relieving physiological stress, whereas MCB is most successful in improving emotional state and reducing anxiety. Broad-leaved forest and mixed forest significantly affected the DBP and vigor level of the subjects, respectively. While coniferous forest did significantly increase the concentration of salivary cortisol in subjects. The study confirmed that compared to the built environment, the natural environment can relieve the human body's physical and psychological stress and negative emotions, while significantly increasing vitality. And different plant communities also have different effects on the physiological and psychological indicators of the subjects. These results will provide scientific basis for the construction and improvement of urban green space environment

The Effect of Organic and Inorganic Modifiers on the Physical Properties of Granite Residual Soil

As a kind of highly weathered special soil in South China, granite residual soils (GRS) feature high strength and high void ratio in a dry environment, so they tend to disintegrate in water and cause geological disasters including collapse. Therefore, modifying GRS for higher strength has become a hot spot. Glass fiber reinforced soils boast fewer cracks, higher energy absorption, and residual strength. This study aims to analyze the reinforcement effect of glass fibers on GRS with inorganic and organic solutions and its environmental feasibility. The inorganic solution contains silicon ion and sodium ion at the ratio of 1 : 4 (hereinafter referred to as Si : Na = 1 : 4 solutions), and the organic one is a modified polyvinyl alcohol solution (hereinafter referred to as SH solution). The reinforced samples were subjected to plate and impact load tests, SEM, and XRD analysis to investigate their mechanical properties, microcharacteristics, and the components produced. Results indicate that the reinforcement effect of glass fibers on GRS under Si : Na = 1 : 4 solutions was better than that of SH solutions. After being reinforced by Si : Na = 1 : 4 solutions, the samples reached maximum impact resistance. SEM results show that glass fibers bond more soil and form an integral structure; thereby the strength was improved as glass fibers share external impact load. XRD results show that geopolymer and alkali-activated materials and potassium feldspar were formed. Geopolymer and alkali-activated materials are pollution-free, inorganic polymers featuring viscosity and high compressive strength. Potassium feldspar is an aluminosilicate mineral with high strength and stable chemical properties, which can adhere to more granules and form a stronger whole structure with geopolymers playing a role. Therefore, it is feasible to reuse these soils sustainably by reinforcing them with glass fibers and the best Si : Na = 1 : 4 solutions. This study finds a new direction for recycling and reusing construction waste, GRS

Sensitivity of Multistage Fill Slope Based on Finite Element Model

Based on the strength reduction method, the laws of slope displacement and the changing positions of the sliding surface during the filling process are studied. The model of multistage fill slope is established by the finite element software PLAXIS. The difference is compared between the slope with no reinforcement and with reinforcement under the same working condition. Sensitivity analysis is carried out from two aspects which are internal factors and external factors. The finite element analysis shows that the settlement of the multistage fill slope with no reinforcement is mainly concentrated on the right side of the slope and gradually decreases with the increase of the filling height. The position of the sliding outlet is located at the joint of the first and the second grade of the slope. The effect of the reinforcement on the sliding surface is ideal. It is obvious that the reinforcement can supply the slope with a better position of the sliding surface, which is beneficial to the stability of the slope. The sensitivity analysis shows that unit weight, ratio of slope, and height of each grade are negatively correlated with the safety factor. At the same time, the platform width, cohesion, and internal friction angle are positively correlated with the safety factor. The internal friction angle has the greatest influence on the stability of the slope. Besides, the platform width and the height of each grade should be controlled at about 4 m. The sensitivity analysis provides a reference for the design of the multistage filling slope

Experimental Study on Interfacial Area Transport of Two-Phase Flow under Vibration Conditions

An experimental study on air-water two-phase flow under vibration condition has been conducted using double-sensor conductivity probe. The test section is an annular geometry with hydraulic diameter of 19.1 mm. The vibration frequency ranges from 0.47 Hz to 2.47 Hz. Local measurements of void fraction, interfacial area concentration (IAC), and Sauter mean diameter have been performed along one radius in the vibration direction. The result shows that local parameters fluctuate continuously around the base values in the vibration cycle. Additional bubble force due to inertia is used to explain lateral bubble motions. The fluctuation amplitudes of local void fraction and IAC increase significantly with vibration frequency. The radial distribution of local parameters at the maximum vibration displacement is specifically analyzed. In the void fraction and IAC profiles, the peak near the inner wall is weakened or even disappearing and a strong peak skewed to outer wall is gradually observed with the increase of vibration frequency. The nondimensional peak void fraction can reach a maximum of 49% and the mean relative variation of local void fraction can increase to more than 29% as the vibration frequency increases to 2.47 Hz. But the increase of vibration frequency does not bring significant change to bubble diameter

Highly efficient isolation and 3D printing of fibroblasts for cultured meat production

Fibroblasts are important components of animal tissues such as muscle and skin, as they are the major producers of various matrix proteins. Matrix proteins such as collagen play an important role in meat products by providing unique nutrition, texture, and flavor. Cultured meat is an innovative meat alternative produced by culturing animal cells, but currently, relatively few studies have been conducted using fibroblasts as seed cells for cultured meat manufacturing. In this work, we first developed an innovative digestion-friction method for isolating fibroblasts from porcine skin efficiently and cost-effectively. After optimizing the enzymatic digestion and physical friction conditions, 2.39 ± 0.28 × 105 fibroblasts were obtained from 1 cm2 of porcine skin tissue, which was about 9 times higher than the conventional tissue explant method. In addition, we identified an edible bio-ink composed of gelatin and chitosan that has good printing properties and supports fibroblast adhesion and growth. Furthermore, we fabricated fibroblast-based cultured meat by 3D printing with an initial cell density of 1.0 × 107 mL−1 and evaluated its texture and nutritional properties. This work provides valuable insights and references for introducing fibroblasts into the production of cultured meat that is more comparable to structured animal meat

Biomass fuels related-PM2.5 promotes lung fibroblast-myofibroblast transition through PI3K/AKT/TRPC1 pathway

Emerging evidence has suggested that exposure to PM2.5 is a significant contributing factor to the development of chronic obstructive pulmonary disease (COPD). However, the underlying biological effects and mechanisms of PM2.5 in COPD pathology remain elusive. In this study, we aimed to investigate the implication and regulatory effect of biomass fuels related-PM2.5 (BRPM2.5) concerning the pathological process of fibroblast-to-myofibroblast transition (FMT) in the context of COPD. In vivo experimentation revealed that exposure to biofuel smoke was associated with airway inflammation in rats. After 4 weeks of exposure, there was inflammation in the small airways, but no significant structural changes in the airway walls. However, after 24 weeks, airway remodeling occurred due to increased collagen deposition, myofibroblast proliferation, and tracheal wall thickness. In vitro, cellular immunofluorescence results showed that with stimulation of BRPM2.5 for 72 h, the cell morphology of fibroblasts changed significantly, most of the cells changed from spindle-shaped to star-shaped irregular, α-SMA stress fibers appeared in the cytoplasm and the synthesis of type I collagen increased. The collagen gel contraction experiment showed that the contractility of fibroblasts was enhanced. The expression level of TRPC1 in fibroblasts was increased. Specific siRNA-TRPC1 blocked BRPM2.5-induced FMT and reduced cell contractility. Additionally, specific siRNA-TRPC1 resulted in a decrease in the augment of intracellular Ca2+ concentration ([Ca2+]i) induced by BRPM2.5. Notably, it was found that the PI3K inhibitor, LY294002, inhibited enhancement of AKT phosphorylation level, FMT occurrence, and elevation of TRPC1 protein expression induced by BRPM2.5. The findings indicated that BRPM2.5 is capable of inducing the FMT, with the possibility of mediation by PI3K/AKT/TRPC1. These results hold potential implications for the understanding of the molecular mechanisms involved in BRPM2.5-induced COPD and may aid in the development of novel therapeutic strategies for pathological conditions characterized by fibrosis