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The effects of four conditioning approaches: Acid, Acid-zero-valent iron (ZVI)/peroxydisulfate (PMS), Fe(II)/PMS and ZVI/PMS, on wastewater activated sludge (WAS) dewatering and organics distribution in supernatant and extracellular polymeric substances (EPS) layers were investigated. The highest reduction in bound water and the most WAS destruction was achieved by Acid-ZVI/PMS, and the optimum conditions were pH 3, ZVI dosage 0.15 g/g dry solid (DS), oxone dosage 0.07 g/g DS and reaction time 10.6 min with the reductions in capillary suction time (CST) and water content (Wc) as 19.67% and 8.49%, respectively. Four conditioning approaches could result in TOC increase in EPS layers and supernatant, and protein (PN) content in tightly bound EPS (TB-EPS). After conditioning, organics in EPS layers could migrate to supernatant. Polysaccharide (PS) was easier to migrate to supernatant than PN. In addition, Acid, Acid-ZVI/PMS or Fe(II)/PMS conditioning promoted the release of some polysaccharides containing ring vibrations v P O, v C-O-C, v C-O-P functional groups from TB-EPS. ESR spectra proved that both radicals of SO4-· and ·OH contributed to dewatering and organics transformation and migration. CST value of WAS positively correlated with the ratios of PN/PS in LB-EPS and total EPS, while it negatively correlated with TOC, PN content and PS content in TB-EPS, as well as PS content in supernatant and LB-EPS. BWC negatively correlated to zeta potential and TOC value, PN content, and HA content in supernatant.

A novel and eco-friendly approach was developed for the scouring and bleaching of flax roves with xylanase, cellulase and mixed enzymes (xylanase and cellulase) in supercritical carbon dioxide fluid (SC-CO2). The results showed that significant improvements in the whiteness and residual gum content of flax roves were achieved in SC-CO2 since xylanase hydrolysed xylan into low molecular oligosaccharides, xylobiose and xylose by hydrolyzing and cleaving β-1,4-glucosidic bonds of xylan. Simultaneously, the hydrolysis reaction of lignin through the hydrophobic and electrostatic interactions at β-O-4 linkages could be effectively facilitated by the catalyst of cellulase in SC-CO2. Furthermore, the whiteness and residual gum content of flax roves were notably influenced by the dosage of enzyme, enzyme ratio, scouring and bleaching temperature, pressure, time and CO2 flow. An optimized enzymatic process for the scouring and bleaching of flax roves was recommended with a dosage of enzyme 3%, an enzyme ratio of 2: 1 (xylanase: cellulase), a system temperature of 50 °C, a pressure of 20 MPa, a CO2 flow of 30 g/min for 90 min in SC-CO2. The whiteness value of flax roves reached to 42.3%, and the value of residual gum content was decreased to 16.95% in the optimum condition.

Peroxone disintegration–Fe(III) coagulation (peroxone–Fe(III)) joint conditioning was proposed to enhance the horizontal electro-dewatering (HED) effect of activated sludge (AS). Operating parameters were optimized and the evolutions of AS physicochemical properties, water fractions distribution, organic matter, extracellular polymeric substance (EPS) key components, functional groups, and protein secondary structures during the process were identified. Under the optimized joint conditioning parameters, dewatered AS achieved a final water content of 84.88 ± 0.17% and its bound water content (BWC) was decreased by 1.88 ± 0.28 g/g dry solid. During peroxone pretreatment, the yielded HO decreased the AS floc size, disintegrated the EPS network structure and cell wall, released the bound water, and extracted proteins, polysaccharides, and humic acid-like materials. Furthermore, soluble microbial byproduct-like materials (SMBP) in the EPS layers and tyrosine in tightly bound EPS significantly increased. Protein structures were destroyed, decreasing their water affinity. Subsequent Fe(III) addition re-coagulated broken flocs fragments and EPS fractions, built water flow channels, removed tyrosine and SMBP, and reduced α-helix percentage in slime, facilitating AS dewatering. After joint conditioning, the bound water and intracellular substances were further released by HED. Therefore, the peroxone–Fe(III)–HED process exhibited an excellent performance in AS water reduction.

Aiming at the fracture mechanics problem of rock material in petroleum engineering, fully illustrated theory of Debond technique is used to simulate and calculate crack propagation in ABAQUS software, and its fracture criterion based on fracture mechanics was introduced. The equivalent domain integral method of calculating stress intensity factor was introduced. The finite element model of rock fracture mechanics of type-I crack was established by Debond technique, and then static stress intensity factor of type-I crack at pure stress boundary condition was simulated and contrasted with analytic solution, which verified the rationality of numerical results. Finally, dynamic stress intensity factor of type-I crack was calculated with increase in loading and crack’s size and accurately predicted the critical stress in the two directions of the simulated rock. The results showed that ABAQUS Debond technique can simulate the fracture mechanics parameters of rock material, and it can effectively describe the fracture mechanics characteristics of rock.

In order to decrease kenaf chemical residues and environmental pollution caused by conventional degumming methods, the present work used a biological enzyme degumming technique to degum kenaf, where the enzyme was the secretion from Aspergillus niger‐kenaf. A neural network model was established based on the experimental results, and the optimal processing parameters of degumming were determined finally with genetic algorithm through a fuzzy relationship between the processing parameters and degumming effects. The optimized parameters are: 34.11°C, pH value 8, bath ratio 1:37.61, time 60 h, and enzyme consumption 1.00 ml/10 g kenaf fiber. The residual gum content and weight‐loss ratio obtained from experimental results were consistent with those given by the model, and the average errors between them were 2.15% and 4.3%, respectively. This work shows that optimized degumming processes could be achieved using this model by avoiding time‐consuming and costly trial‐and‐error tests.

The home-made equipment and its working principle were introduced. Dyeing by this equipment makes the color fastness to rubbing, sunning and washing of modified cotton fabrics to reach level 4-5, as well as a good dyeing evenness. Design the automatic control system of Supercritical CO2 Fluid dyeing equipment, and research on practical applications of fuzzy controller is investigated. On analysis of the features of technique, in order to reach a good dyeing effect, controlling the temperature and pressure of dyeing equipment is the key technology development of control system. Those variables have the characters of non-linearity, time-variation, and inter-coordination, etc. Fuzzy control strategy can enhance the capacity of resisting disturbance of system in different states and external conditions, which can reach an excellent control effect. Therefore, the research utilizes fuzzy controller to control the equipment, which makes its process parameter realize the real-time monitor and accuracy control under the condition of close to the optimal condition. Also, human-machine interaction interface increases the programming quality, and makes the functions of monitor and control reasonably arranged.

This paper is about auto-control system of the dyeing equipment by supercritical CO2, and then design the fuzzy logic controller (FLC) and study the application in practice. After dyeing with this equipment, the fastness to rubbing, sunfast and laundry resistant of fibre textile can all be grade 4. The dyeing uptake rates can reach to 86%. Furthermore, the solubility of dyeing using this equipment can reach the uniformity effect. Getting across to analyse the characteristic of the technics, the parameter of the pressure and the temperature must be controlled, which is the key to develop control system and to achieve the favorite effect. Therefore, the FLC is introduced into the auto-control system. It is realized that the parameters of this process are measured in real time and controlled accurately. When the parameters controlled are close to the condition of optimization, the favorite effect has been achieved.

Supercritical CO2 fluid dyeing, a new type of anhydrous dyeing technology, has the advantage of high uptake rate, short dyeing process, recycling of dyes and CO2, and zero discharge. This study investigated a dyeing technique of loose fibers using supercritical CO2 as solvent to replace water. Based on the existing characteristics of the self-developed supercritical CO2 dyeing equipment, a special dyeing frame of loose fibers was designed. Using the dyeing frame and inner and outer dyeing processes, polyester fibers were dyed with disperse red 153# maternal dyes at temperatures of 80–140?, pressures of 17–29MPa and time of 20–80min, respectively. The experimental results revealed that the dyeing performance of fibers was good on the dyeing frame, as well as with a favorably increased temperature, pressure and time. Dyeing temperature had a strong influence on the color yield. The dyeing results were compared with those of polyester fibers dyed with disperse red 153# dyes. With the special dyeing frame of loose fibers, color fastness to washing and artificial light was generally similar to conventional aqueous medium methods.