Superhydrophobic fiber membranes have become a hotspot of research in the field of functional surfaces due to their unique surface properties. Electrospinning as an emerging technique is simple to operate, and can effectively modulate the surface morphology of nanofibers and realize micro/nano double structure selfassembly. Thus, superhydrophobic micro/nano fiber surface materials are obtained. The surface morphology and physical properties of the micro/nano fibers prepared by this technique are close to those of natural fiber superhydrophobic materials. This article first introduces the selfcleaning theorectical basis of superhydrophobic surface materials and the technical principle of electrospinning in brief, and then focused on the latest research progress of electrospinning technology to prepare superhydrophobic surface materials.
Adopt solvent refining and chemical caustic washing method to enrich and extract phenolic compounds from Fushun shale oil, then analyzed and identified with gas chromatographymass spectrometry (GC-MS). Fushun shale oil is extracted with N, N-dimethyl formamide (DMF) solvent, and the extracted phase of oil the initially enriched phenolic compound is obtained. The phenolic compounds are converted into phenol sodium salt dissolved in the inorganic phase by chemical caustic washing method, then reverse extract via acidification after separation to obtain phenolic compounds. Through the analysis and identification, the relative mass fraction of phenolic compounds in Fushun shale oil will be increased from 4.06% to 73.74% after enrichment. 49 kinds of phenolic compounds are identified in the extracted products, mainly for phenol class, including C3 phenol compounds with the highest mass fraction at 27.69%, and followed by C2 and C4 phenols at 19.18% and 15.96%, respectively.
In oil refining enterprises, different oil refining process would produce a certain amount and quality of wastewater. Based on the tracking model of material flow analysis method, all the water process was integrated into the water balance system, and the optimization model and evaluation index system of the water supply network were established. Taking the oil refinery in China as an example, the water network model of the oil refining production process was constructed, and the minimum water consumption problem of the current water system was determined. The method was optimized and evaluated. The results showed that the fresh water consumption could be reduced by 26.90% and the sewage discharge could be reduced by 84.42% after taking the water system optimization measures. Waterenvironmental efficiency increased by 15.34%.
Four kinds of new metal organic complexes are introduced, namely, [ZnL1(cis-2-Butenedioicacid)2 ]n (complex 1), [Zn2(L1)2 (pnitrobenzoicacid) 2 ]n (complex 2), [MnL1(p-nitrobenzoicacid)2 ]n (complex 3), [Mn2(L1)2(p-nitrobenzoicacid) 2Cl2]n(complex 4). The nitrogen donor in the triangular rigid ligand (L1=4-bromine-2,2′: 6′,2″ripyridine) is synthesized with the oxygen donor in the semirigid ligand (maleic acid and p-nitrobenzoic acid). X-ray single crystal diffraction results show that complex 1 is one-dimensional chain structure, and complexes 2—4 are all zero microstructures. The infrared spectra (IR) and thermogravimetric analysis (TGA) of the complexes have been carried out. The results show that the complexes have good thermal stability. The antibacterial experiments of these crystals have been studied at the same time.
Nitrobenzene has high toxicity, good stability and great difficulty in degrading in the water, which is easy to cause harm to human health and natural environment. Researchers at home and abroad have been attracted by how to deal with the nitrobenzene in wastewater. This paper discusses the main methods for the degradation of nitrobenzene wastewater currently used in physical, chemical and biological methods, and made a prospect of the research. Finally, it is pointed out that the integrated of various methods for nitrobenzene degradation is the focus of future research.
Aiming at the problem that the weak gel system has poor effect on the high temperature and high salinity reservoirs, a kind of polymer nanosphere HP-2 system with temperature resistance and salt tolerance was developed. The particle size distribution and morphology of HP-2 were evaluated by laser particle size analyzer and optical microscope. The water absorption expansion curve of HP-2 was studied by using swelling ratio as the evaluation index. Finally the plugging, anti erosion and profile control performance of polymer nanosphere HP-2 were evaluated using homogeneous cores and heterogeneous cores. The results showed that the polymer nanosphere HP-2 with an average particle size of 407.2 nm were spherical particles with high sphericity. The water swelling ratio of HP-2 was 34.1 g/g in the high temperature (90 ℃) and high salinity (97 686 mg/L) reservoir. The results of three layers heterogeneous core flooding experiments show that the polymer nanosphere HP-2 system can enhance the oil recovery rate by 17.3% on the basis of water flooding recovery. The polymer nanosphere HP-2 system has wide application prospects in high temperature and high salinity reservoirs.
Zn(OH)2 carbon composite microspheres were prepared by hydrothermal method using sucrose as template and then roasted to form the ZnO hollow microspheres. The effects of calcination rate on the morphology and pore structure of ZnO hollow microspheres were investigated. The structures of the hollow microspheres were characterized by XRD, TG, SEM and N2 adsorption. Then, the NiO/ZnO adsorbents with 5% Ni content were prepared by equal volume impregnation method. The results show that when the calcination rate is 3 ℃/min, the specific surface area and pore volume of hollow microspheres are as high as 37.21 m2/g and 0.483 cm3/g respectively; when the adsorption temperature is 350 ℃， the pressure is 1.2 MPa, the volume space velocity is 6 h-1 and the volume ratio of hydrogen to the simulated oil is 60, the desulfurization rate of the Ni/ ZnO adsorbent can reach as high as 96%， which has potential value in application.
Emulsified asphalt mixture can open up traffic in advance, greatly facilitate the masses of travel, improve production efficiency, and promote the development of the local economy. It has been widely promoted around the world. However, there are many problems in emulsification technology, such as the inability to resist freezing damage, poor adhesion, poor aging resistance and so on. After repeated studies, adding a polymer modified material was added on the basis of adding emulsifiers, and a new kind of emulsified asphalt with superior performance was compounded. According to the mechanism of emulsifier modification, the slow cracking fast condensing emulsifier and SBS polymer modified material were selected, and the mixture ratio test was started by compounding methods. Finally, the performance test indexes are compared to determine the optimal mix ratio for emulsified asphalt, which provides the possibility for the pavement application of emulsified asphalt. After being paved in the test section, the result shows that the application of modified emulsified asphalt material in the G205 Huiyang section is excellent, and it can open up the traffic in advance to meet the requirements of industry standards, and conforms to the development concept of green and low-carbon.
The most important form of loss of energy in long-distance gas pipelines was turbulence resistance. In order to study the V-shaped riblet influence on the resistance in the gas pipeline, this paper used the software of CFD to simulate two different geometric size of V-shaped riblets and smooth pipe. The Reynolds number was 74 880. By analyzing the flow field in the pipeline, the distribution of vorticity and wall shear stress, the reasons for increasing drag and decreasing resistance were found. Based on this, the drag reduction mechanism was obtained. The results showed that：compared with the smooth gas transmission pipeline，when the riblet size in the pipeline was s+=22, the flow velocity, vorticity value, the area of wall shear stress and the shear stress were small. Riblet had the effect of drag reduction. When the riblet size of the pipeline was s+=44, the flow velocity of the near wall area, the vorticity value at the top of the riblet, the wall shear stress increased area and the shear stress value was large. Riblet had the effect of increasing resistance.
The calculation of temperature drop was one of the most important parameters in the repair process of hot oil pipeline, and the value played an important role in the pipeline excavation repair plan and oil transportation. The thermodynamic model of unsteady state after excavation was established from the view of thermodynamics, and the simulation was carried out on the basis of a case study of the hot oil pipeline from Songshan to Jinzhou. The influence of the different starting points, excavation length and oil station temperature on the oil temperature of hot oil pipeline was studied combined with CFD in different seasons of excavation operation of hot oil pipeline and the soil temperature field around the changes of numerical simulation analysis. The results of the study could ensure the safe operation of the pipeline under the premise of providing hot oil pipeline excavation repair recommendations and guide the management department to optimize the construction repair plan.
Using the method of qualitative and quantitative combination, the risk identification and pre-risk analysis of CNG filling stations were carried out by using the principle of system safety engineering. And the FLACS software based on computational fluid dynamics was used to simulate the accident situation of the filling station leakage. The influence of different wind speed on the leakage accident and the different ignition position on the explosion accident were studied, so as to provide the data support for the design of the safe distance and the safety barrier to reduce the accident risk. The results showed that the volume of the gas cloud increases rapidly within a few seconds of the beginning of the leakage, but the volume of the gas cloud exploded in a stable state over time; the larger the wind speed was, the farther the diffusion distance of the gas cloud, but the actual dangerous concentration volume gradually decreased; different ignition locations would cause different over-pressure, where the edge of the ignition caused by the explosion over-pressure was greatest and the center ignition produces an explosion over-pressure minimum
Through grey prediction GM (1, 1) model calculation and Matlab software prediction, the prediction of ground motion response of 400 m3 storage tank is studied.First, the liquid height difference of the reservoir is set to 0.5 m, the total force, the base bending moment of the storage tank and the axial stress of tank wall under the horizontal earthquake are predicted under the different height of liquid storage.The prediction absolute error map is drawn, and the influence of earthquake intensity on the prediction error is obtained. Then, in order to further reduce the prediction error, the prediction effect is improved and the liquid height difference of the storage tank is adjusted to 1.0 m，reprediction the dynamic response of the storage tank. It is concluded that the interval of the high liquid difference data sequence of the storage tank increased from 0.5 m to 1.0 m. The relative error of the prediction results of the total horizontal seismic force and the base bending moment of the storage tank is reduced, after improvement, the prediction effect of bending moment and the axial stress of tank base are good.
Based on the field investigation of the leakage of pipeline transportation and combining with the latest research direction of emergency management mechanism, it was found that the stochastic Petri net model suitable for this kind of problem was modeling. Taking the Huangdao oil pipeline leakage accident as an example, the data of emergency management flow of pipeline transportation leakage were collected and processed, and isomorphism Markov chain to study the change utilization rate and average delay time was used. The results of the study indicated that the coordinated treatment of pipeline leakage systems, protection of the affected areas and the transfer of the masses took the most time in emergency operations. Therefore, intensifying the cooperation between the central construction administrative agencies and the local construction administrative agencies and perfecting the mass transfer and resettlement system were reasonable measures to strengthen emergency management of pipeline leakage and minimize economic losses.
The rectangular beams were widely used in architectural engineering, cracks would be appeared with the increase of service life and some human factors, and any cracks in it might cause hidden risks. The SIF was a physical quantity that reflected the elastic stress field of the crack tip, which was related to the size of the crack, the geometrical characteristic of the component and the load. Meanwhile, it was very important to find a simple method to solve the SIF for not only the fracture theory but also engineering application, as it was a key content of fracture mechanics. In previous studies, the shape of initial crack must be known to get SIF, but it was very difficult to be seen under the condition of test. This paper took the bending beam as an example, a new method to formulize the SIF for three kinds of cracks in rectangular beam under bending load was proposed by the basis of the conservation J integral.
According to the analytic hierarchy process (AHP) and referring to the national standard, the evaluation index of the energy consumption of the centrifugal pump system and the evaluation system of the centrifugal pump system were established. By using the theory of fuzzy mathematics, a complete evaluation method was formed.Using Matlab to solve the matrix of the largest features to determine the weight of each factor.The threshold value of each factor was obtained by statistical method, and the fuzzy matrix of each factor was obtained.The evaluation of energy consumption of a centrifugal pump in a factory was carried out. The evaluation results showed that the pump efficiency was the main factor affecting the centrifugal pump system;the energy consumption grade of the centrifugal pump system was 2, and the overall operation of the system was reasonable; in the single factor evaluation, the energy efficiency level of transmission efficiency was 4, which indicated that the drive mechanism was not running properly and needed to be handled.Therefore, this method had an important guiding significance for the energysaving transformation of the centrifugal pump system.
The analysis of texture direction feature of strip surface defects was reasonable or not affected the correctness of defect image recognition. To strip surface defects and texture direction feature abstraction which described defect image, the relationship between detection distance and detective direction angle and the basic methods of texture direction feature abstraction of defect image were given. Based on the case studies of crack defect image to strip surface with both noise and noise free, the texture feature should take the maximum value in texture direction and the minimum value in the direction perpendicular to the texture were proposed. The detection distance should be selected according to the specific situation, not too large or too small and the threshold value should be small when analysis defect image with noise.
The KNN classification algorithm is nonparametric, easy to understand and relatively efficient, and is widely used in many fields. In the traditional KNN algorithm, the Euclidean distance method considers the contribution of all the attributes of the sample as the same. But in fact, the contribution of different attributes of the sample is not necessarily the same. To solve this problem, an improved KNN algorithm based on analytic hierarchy process is proposed. In the improved algorithm, firstly, the weights of each attribute of the sample are calculated by using the analytic hierarchy process, and then the sample distance is calculated by using the weighted Euclidean distance, thereby classifying according to the weighted distance. In the experiment, with the increasing number of training samples, the efficiency of AHP-KNN algorithm is improved, and it is gradually better than the efficiency of the FCD-KNN algorithm and the traditional KNN algorithm. The simulation results show that the improved algorithm proposed can effectively improve the classification accuracy of the traditional KNN algorithm, and has certain theoretical and practical value.
This paper is concerned with the synchronous H∞ switching control problem for a class of discretetime delay switched systems with time-varying delay under partially delay-dependent controller. Using the multiple Lyapunov function and the average dwell time method, the conditions for the average dwell time are satisfied. Under this switching condition, the system is mean square exponent stable and has weighted H∞ performance. At the same time, the design of the H∞ switching controller is given. Finally, a numerical example is used to illustrate the effectiveness of the proposed design method.
