Analysis of changes and influencing factors of stablization treatment effects and bioavailability after freeze-thaw: a case study of Pb-contaminated soil in a non-ferrous metal factory in Northeast China

IntroductionSolidification/Stabilization techniques are commonly used for the containment and isolation of Pb-contaminated soil, but they cannot reduce the amount of contaminants. Freeze – thaw after stabilization may affect Pb’s environmental behavior and increase the uncertainty of environmental risk.MethodsIn vitro experiments can simulate the bioavailability of heavy metals to the human body, accurately assessing their environmental health risks. In this study, soil samples from Pbcontaminated site are collected from a non-ferrous metal plant in Northeastern China. Through the results of stabilization and freeze–thaw after stabilization experiments, analyzing the changes of physicochemical property, Pb treatment effects (total concentration, leaching concentration, and occurrence forms) and microbial communities, and studying the influencing factors of Pb’s bioavailability.Result and discussionThe results show that stabilization and freeze – thaw after stabilization directly alter soil physicochemical property, thereby affecting the leaching and occurrence form of Pb and microbial communities, and closely related to changes in bioavailability of Pb. Both stabilization and freeze–thaw treatment reduced the leaching concentration of Pb, decreased the proportion of available Pb (acid-soluble state, oxidation state and reduction state), increased the bioavailability of Pb in the gastric phase, but decreased in the intestinal phase; And the dominant bacterial phylum in the soil changed to Firmicutes, the dominant bacterial genus changed to Bacillus; The analysis of the results shows that the bioavailability of Pb is related to soil pH, cation exchange capacity (CEC), soil organic matter (SOM), soil moisture content (SMC), Pb (leaching, acid soluble state, oxidation state, residual state), types of microorganisms in soil

A catalyst-free and facile route to periodically ordered and c-axis aligned ZnO nanorod arrays on diverse substrates

In this work we present a method for the deposition of periodically ordered, c-axis aligned ZnO nanorod arrays. By using chemical bath deposited films in conjunction with silica templating through nanosphere monolayers, masks suitable for high temperature deposition are created. A vapour phase transport technique is then used to deposit ordered arrays, quickly and inexpensively in a manner ideal for low cost, scalable and reproducible growth on a diverse range of substrates

PLA/Coffee Grounds Composite for 3D Printing and Its Properties

Coffee is one of the most popular beverages in the world. It generates a waste known as coffee grounds. In this work, changes in mechanical properties, crystallinity index, and DSC characteristics of PLA/coffee grounds with different dosages were analyzed by XRD, DSC, and mechanical property tests. Statistical analysis showed that the modulus of rupture of PLA/coffee grounds 3D printing materials was maximal at 109.07 MPa and 3604 MPa when 3% coffee grounds were added. The tensile strength of the untreated PLA complex was 49.99 MPa, and the tensile strength increased from 49.99 MPa to 51.28 MPa after 3% coffee grounds were added. However, there was no significant difference between the PLA complex and PLA/coffee grounds 3D printing materials when the additions were lower than 3%. The statistical analysis showed that when the coffee grounds additions increased from 5% to 7%, the tensile strength of PLA/coffee grounds 3D printing products significantly decreased. For example, the tensile strength decreased from 49.99 MPa to 26.45 MPa with addition of 7% coffee grounds. The difference between the glass transition, cold crystallization, and melting temperatures of PLA coffee grounds 3D printing materials was almost negligible, which indicates that the thermal properties of PLA coffee grounds 3D printing materials are comparable to those of PLA, and that the processing temperature and FDM printing temperature of the PLA filament are suitable for application to the PLA coffee grounds 3D printing material system

Research on the Change in Chemical Composition and Fungal Resistance of Moso Bamboo with Heat Treatment

Bamboo, as a potential alternative to biomass materials, has gained more attention from the bamboo manufacturing industry in China. However, the drawbacks, such as the dimensional instability, and low antifungal and hydrophilic properties of bamboo, inhibit its application and shorten its service life. The objective of this work was to analyze the change in chemical components and fungal resistance of moso bamboo with heat treatment. For this objective, moso bamboo specimens were thermally modified in an oven at different temperatures for a fixed duration. The results showed that the parenchymal cells distorted and deformed in comparison to the control after thermal modification. After thermal modification in an oven, the crystallinity index increased from 39% to 53%. Owing to the thermal modification, the hemicellulose and cellulose relative content decreased, as confirmed by FTIR and XPS analysis. Thus, the dimensional stability and antifungal properties of the thermally modified bamboo specimens improved

Behavioral Risky Multiple Attribute Decision Making with Interval Type-2 Fuzzy Ranking Method and TOPSIS Method

Considering the decision maker’s psychological state will influence their evaluation result in the risky multi-attribute decision-making problem, and the uncertainty of evaluation information. In this paper, we will propose a behavioral risky multiple attribute decision making with interval type-2 fuzzy ranking method and TOPSIS method. The interval type-2 fuzzy set is used to express the uncertainty of evaluation information, the prospect theory is applied to describe people’s psychological state in the processing of risk decision making. First, we define a new ranking method for interval type-2 fuzzy set to compare the interval type-2 fuzzy evaluation information and the expectation. Second, we give a relative distance for interval type-2 fuzzy set to get the distance between the interval type-2 fuzzy evaluation information and expectation. Third, we use the prospect theory, the new defined ranking method and the new defined distance formula to obtain the comprehensive prospect value. Fourth, we use the improved TOPSIS method and the comprehensive prospect value to rank the alternatives. Based on the above-mentioned steps, we give the solution for risky interval type-2 fuzzy multiple attribute decision-making problem, which named as the behavioral risky multiple attribute decision making with interval type-2 fuzzy ranking method and TOPSIS method. Finally, we use an example to show the rationality of this method. </jats:p

Research on the Change in Chemical Composition and Fungal Resistance of Moso Bamboo with Heat Treatment

Bamboo, as a potential alternative to biomass materials, has gained more attention from the bamboo manufacturing industry in China. However, the drawbacks, such as the dimensional instability, and low antifungal and hydrophilic properties of bamboo, inhibit its application and shorten its service life. The objective of this work was to analyze the change in chemical components and fungal resistance of moso bamboo with heat treatment. For this objective, moso bamboo specimens were thermally modified in an oven at different temperatures for a fixed duration. The results showed that the parenchymal cells distorted and deformed in comparison to the control after thermal modification. After thermal modification in an oven, the crystallinity index increased from 39% to 53%. Owing to the thermal modification, the hemicellulose and cellulose relative content decreased, as confirmed by FTIR and XPS analysis. Thus, the dimensional stability and antifungal properties of the thermally modified bamboo specimens improved.</jats:p

Behavioral risky hesitant fuzzy linguistic multiple attribute decision making with priority degree method

Abstract In this paper, we propose a behavioral risky hesitant fuzzy linguistic multiple attribute decision making with priority degree method. First, we define a new ranking method for hesitant fuzzy linguistic term sets to compare the hesitant fuzzy linguistic evaluation information and the expectation. Second, we give a relative distance for the hesitant fuzzy linguistic term set to get the distance between the hesitant fuzzy linguistic evaluation information and expectation. Third, we use the prospect theory, the new defined ranking method and the new defined distance formula to get interval individual prospect value. Forth, we apply the average operator to get interval comprehensive prospect value. Fifth, we define a priority degree method of interval number to rank interval comprehension prospect value. Based on the above steps, we give the solution of risky hesitant fuzzy linguistic multiple attribute decision making problem. Further, we use the example to illustrate the feasibility and rationality of this behavior method and the comparative analysis between the existing decision making method for the hesitant fuzzy linguistic term.</jats:p

A Novel Automated Guided Vehicle (AGV) Remote Path Planning Based on RLACA Algorithm in 5G Environment

Remote control and monitoring will become the future trend. High-quality automated guided vehicle (AGV) path planning through web pages or clients can reduce network data transmission capacity and server resource occupation. Many Remote path planning algorithms in AGV navigation still have blind search, path redundancy, and long calculation time. This paper proposed an RLACA algorithm based on 5G network environment through remote control of AGV. The distribution of pheromone in each iteration of the ant colony algorithm had an impact on the follow-up. RLACA algorithm changed the transfer rules and pheromone distribution of the ant colony algorithm to improve the efficiency of path search and then modify the path to reduce path redundancy. Considering that there may be unknown obstacles in the virtual environment, the path obtained by the improved ant colony algorithm is used as the training data of reinforcement learning to obtain the Q-table. During the movement, the action of each step is selected by the Q-table until the target point is reached. Through experimental simulation, it can be concluded that the enhanced ant colony algorithm can quickly obtain a reasonable and adequate path in a complex environment and effectively avoid unknown obstacles in the environment.</jats:p

FDM 3D Printing and Properties of WF/PBAT/PLA Composites

Fused deposition molding (FDM) is a commonly used 3D printing method, and polylactic acid (PLA) has become one of the most important raw materials for this technology due to its excellent warping resistance. However, its mechanical properties are insufficient. Polybutylene adipate terephthalate (PBAT) is characterized by high toughness and low rigidity, which can complement the performance of PLA. The biodegradable polymers produced by blending the two have thus been used to replace petroleum-based plastics in recent years, but the high cost of the blends has limited their wide applications. Introducing plant fibers into the blends can not only maintain biodegradability and improve the overall performance of the plastics but also reduce their costs greatly. In this study, the PBAT/PLA blends with a mass ratio of 70/30 were selected and mixed with wood flour (WF) to prepare ternary composites using a FDM 3D printing technique. The effects of WF dosage on the mechanical properties, thermal properties, surface wettability, and melt flowability of the composites were investigated. The results showed that the proper amount of WF could improve the tensile and flexural moduli of the composites, as well as the crystallinity and hydrophobicity of the printed specimens increased with the content of WF, while the melt flow rate decreased gradually. Compared to PBAT/PLA blends, WF/PBAT/PLA composites are less costly, and the composite containing 20 wt.% WF has the best comprehensive performance, showing great potential as raw material for FDM 3D printing

A Novel Sparrow Particle Swarm Algorithm (SPSA) for Unmanned Aerial Vehicle Path Planning

Unmanned aerial vehicle (UAV) has been widely used in various fields, and meeting practical high-quality flight paths is one of the crucial functions of UAV. Many algorithms have the problem of too fast convergence and premature in UAV path planning. This study proposed a sparrow particle swarm algorithm for UAV path planning, the SPSA. The algorithm selects a suitable model for path initialization, changes the discoverer position update, and reinforces the influence of start-end line on path search, which can significantly reduce blind search. The number of target points reached is increased by adaptive variable speed escapes in areas of deadlock. In this case, the planned trajectory will fluctuate, and adaptive oscillation optimization can effectively reduce the fluctuation of the path. Finally, the optimal path is simplified, and the path nodes are interpolated with cubic splines to improve the smoothness of the path, which improves the smoothness of the UAV flight trajectory and makes it more suitable for use as the UAV real flight trajectory. By comparison, it can be concluded that the improved SPSA has good convergence speed and better search results and can avoid local optimality.</jats:p