Nano-titanium can be used in the field of anticorrosive coatings due to its excellent corrosion resistance. In this paper, phenolic resin was modified by nano-titanium using a physicochemical method. The nano-titanium-modified phenolic resin was used as a matrix to prepare the anticorrosive coating. The microstructures of the coatings were analyzed by Scanning Electron Microscope (SEM), X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR). Raman and UV spectrum adhesion of the coating was tested by a scratching method. The corrosion behavior was studied by electrochemical workstation and salt spray test. The results showed that the corrosion resistance of pure phenolic resin coating was significantly improved by the nano-titanium-modified phenolic resin. The coating containing 4% titanium nanoparticles exhibited the best corrosion resistance, with the highest impedance and the smallest corrosion current. The coating remained intact after 480 h of salt spray, showing the best salt spray resistance performance.
This article proposes a modeling method for the SPSO-WNN neural network in absorbers used in absorption refrigeration systems. The method establishes the input-output structure of the absorber model by analyzing the absorber’s working principles. A WNN neural network with a single implied layer is selected as the internal structure of the model, and the number of nodes in the implied layer is determined using the root mean square error and a trial-and-error method of decision coefficients. To address the limitations of the WNN neural network and improve the model’s prediction accuracy, the article uses Morlet wavelet basis functions and a simple particle swarm algorithm to improve the determination of the traditional neural network’s activation function in the hidden layer and the parameters of the neural network’s weights, scaling factor, and translation factor. The results of experimental simulations show that the absorber SPSO-WNN model established in this paper has less error than the traditional WNN neural network model, with the root mean square error of the two outputs being 1.73% and 2.36%, respectively. The model established by this method is simple and effective and can be used as an equation constraint in the optimal operation control strategy of absorption refrigeration systems.
The utilization of polymer additives for drag reduction stands as a crucial method in achieving reduced resistance in pipelines.As a common pipe fitting in the pipeline system,the study of the sudden expansion pipe flow holds significant importance for flow drag reduction and energy conservation.The numerical simulation method is used to examine the turbulent flow of the polymer PAM(polyacrylamide)solution in a sudden expansion pipe through the Cross model,and the flow field,drag reduction patterns and the variations in the recirculation zone are also analyzed.Results indicate that,the pressure recovery maximum of PAM solution is greater than that of water under the same Reynolds number.The drag reduction rate in the upstream straight pipe exhibits an initial increase followed by a decrease with the rise of Reynolds number.The local resistance coefficient of sudden expansion in PAM solution increases with the increase of Reynolds number,and shows a drag reduction effect,but the drag reduction rate is noticeably lower than that of the straight pipe.Furthermore,under the same Reynolds number,the length of the recirculation zone in PAM solution experiences an increased length compared to pure water.This alteration and the observed drag reduction effect are related to the change of turbulent kinetic energy.
The wastewater treatment capacity of algal-bacterial symbiotic systems can be further improved by optimizing the process parameters during advanced wastewater treatment using the response surface method.This study employed the response surface method(RSM)to optimize the aeration volume and CO2 volume fraction in algal-bacterial symbiotic system,analyzing its impact on the removal rates of nutrients to achieve optimal removal efficiency.The results indicate that the removal rates of Total Nitrogen(TN)and Ammonium Nitrogen(NH3-N)are significantly influenced by the aeration volume,whereas the removal rates of Total Phosphorus(TP)and Chemical Oxygen Demand(COD)are more susceptible to changes in CO2 volume fraction.The optimal aeration conditions predicted by the response surface method were an aeration volume of 0.639 L/min and a CO2 volume fraction of 3.849%.Under these conditions,the removal rates of TN,TP,NH3-N and COD reached their were maximum values within 2 days,achieving 70.040%,72.925%,100%and 83.612%respectively.
Rapid and accurate automatic landslides identification is of great significance to geological hazard survey,management and risk assessment.In this paper,Google Earth images are utilized to construct a sample set of historical landslides,and the Mask R-CNN object detection algorithm is employed to detect massive landslides automatically.The proposed method is demonstrated by two case studies in Danba County,Sichuan Province and Yongjing County,Gansu Province.Considering the factors which affect the occurrence of landslides,taking Danba County as an example,this paper uses the multi-layer perceptron mode to obtain the occurrence probability map of landslides.The accuracy of landslides detection is further validated by comparing the distribution of landslides detected by Mask R-CNN against the landslides occurrence probability map.The results show that the precision of landslide detection is 96%,recall is 85%,F1 score is 0.90,and 79%of the points are distributed in the area where the probability of landslides occurrence is higher than 80%;the precision of loess landslides detection is 98%,recall is 65%,and F1 score is 0.78.This method can effectively improve the automation of geological hazard information acquisition and the accuracy of landslides detection.
The opening beam can effectively reduce the structural height and self-weight,but the existence of holes has a certain impact on the mechanical performance of the beam.Based on the plastic damage finite element model,this article analyzes the effects of different opening parameters such as shape,aperture,horizontal and vertical positions on the ultimate bearing capacity,deformation and ductility of reactive powder concrete(RPC)opening beams.The results show that when the opening area is the same,there is not much difference in the mechanical performance between RPC opening beams with different opening shapes.The ultimate bearing capacity and ductility of the opening beam decrease with the increase of the aperture,while the deformation increases with the increase of the aperture.When the hole is located in the bending-shear zone,the ultimate bearing capacity and ductility of the opening beam are significantly reduced compared to opening beams within the pure bending zone.The influence of holes biased towards the compressed zone of concrete on the ultimate bearing capacity,deformation,and ductility of the open-hole beam is very significant.Based on the mechanical performance of opening beams,corresponding design suggestions for the arrangement of holes in RPC beams are proposed.
The efficiency advantage of combined transportation mode compared with single transportation mode is not only reflected in the utility of travelers,but also in improving the overall efficiency of the transportation system.Therefore,the spatio-temporal efficiency can be used as an indicator to comprehensively analyze and evaluate the selected mode and route.This article analyzes the generalized travel cost of each stage of combined travel on the platform of a super network,establishes a mode-route joint model,and solves for the traffic sharing rate of each path.It proposes the concept and calculation method of spatio-temporal efficiency for combined travel from the perspectives of travelers and decision-makers,and evaluates the spatio-temporal efficiency of various routes through case studies.The results show that the spatio-temporal efficiency depends on the combination of public transportation modes,with metro routes having generally high spatio-temporal efficiencies.The spatio-temporal efficiency value of the"bus+metro"combination is highest at 1.13,which is 5.3%higher than the combinations with only metro and 85.4%higher than those with only buses.In combined short-distance and long-distance or medium-distance and long-distance travel,the spatio-temporal efficiency advantage of the metro is much higher than other modes.
Desalination technology has become mature in China.The application of dew point evaporation desalination technology in solar greenhouses to develop and utilize various types of brackish water resources for crop irrigation is a practical research endeavor.Based on the principle of dew point evaporation desalination,this article designs a dew point evaporation brackish water desalination system for solar greenhouses and analyzes the changes in temperature,humidity,and water production through simulation calculations.The results show that under conditions of return air,the highest temperature and humidity inside the greenhouse reach 27.18℃and 89%respectively,meeting the requirements for normal crop growth.As the proportion of return air increases,the water production inside the greenhouse shows an increasing trend.When the return air rate is 100%,the maximum water production reaches 2 kg,which is sufficient to meet the normal irrigation needs of crops.
Nanjing metropolitan circle is an important inter-provincial cooperative metropolitan area in China.The study of the spatial disequilibrium can provide theoretical support for the positive interaction between regional traffic and economic development.Based on the coupling coordination relationship between traffic dominance and economic development,this paper constructs an evaluation index system and systematically analyzes the spatial pattern of traffic dominance and economic development in Nanjing metropolitan circle.The characteristic types and development differences of different district and county unit are expounded.The results show that there is a significant polarization effect in Nanjing metropolitan circle,with a range of 0.94,forming a traffic advantage zone along the Yangtze River from high to low.The level of economic development shows a pyramid-shaped structure,nearly 60%of the districts and counties below the average,presenting a"multi-core"circle structure.The coupling coordination relationship between the two is generally good,but the coordination degree is low.The coupling degree of 88.3%evaluation units is more than 0.90,and the interaction is obvious.
The simple support to continuous strengthening method proves to be an effective solution to solve the problems of existing purlin strengthening methods,such as large steel consumption and low construction efficiency.The finite element software ABAQUS is used to strengthen simply supported C-shaped steel purlins of different spans with embedded continuous reinforcement,and the lap length coefficient α take 0.02～0.20,according to the continuity index β,and the reasonable lapping length of simply supported C-type steel purlins was obtained according to the continuity index β.And the connection performance of bolting connection and structural adhesive connectionat the support of simply supported C-shaped steel purlins is compared and analyzed.The results show that the lapping length of simply supported C-shaped steel purlin embedded continuous strengthening should be≥10%L,and when the lap length coefficient α take 0.10,the continuity index of embedded C-shaped steel purlin β can reach 90%and meet the purlin reinforcement requirements.Considering the construction operability and reinforcement cost of the two connection methods at the support of simply supported C-shaped steel purlin,the bolting connection can be preferentially selected for the embedded continuous reinforcement of simply supported C-shaped steel purlin.
Investigating the relationship between urban road networks and the layout of commercial facilities contributes to urban economy and the efficient allocation of resources..Using the central district of Jinan as a case study,the study analyzes the morphology of the urban road network and its correlation with the distribution of commercial facilities,and employs multiple scales based on the line segment model of spatial syntax,the kernel density estimation and the nearest neighbor distance method.The results reveal that commercial facilities in the central district exhibit a multi-core clustering distribution.While automotive service facilities are situated on the periphery of the central urban area,other types of facilities tend to cluster extensively in the main urban area.There are spatial differences in the distribution characteristics of the road network and the spatial synergy is general.The main urban area's road network predominantly undertakes the responsibilities of integration and traffic bearing,while the new urban areas in the east and west lack the capacity for integrating and penetrating local urban space.There are differences in the impact of road network morphology on the layout of commercial facilities,with automotive services being less influenced and gastronomy being more dependent on road network morphology.All types of commercial facilities tend to be situated near road networks characterized by high accessibility and integration.
Ultrasonic vibration cutting,as an advanced machining method,is commonly applied in the machining of challenging materials such as titanium alloy.Analyzing the influence of ultrasonic vibration cutting on the vibration signal and the surface structure of the machined surface during the cutting process can provide valuable insights for subsequent research.Utilizing the finite element software ABAQUS,a two-dimensional cutting finite element model was established to simulate conventional cutting and radial and tangential ultrasonic vibration cutting with different amplitudes.Based on the simulation results,the optimal ultrasonic vibration cutting scheme was selected for the experiment,focusing on the changes and in vibration signals and the surface structure of the machined surface during the cutting process.The results indicate that radial ultrasonic vibration cutting with an amplitude of 10 μm exhibits obvious advantages,with a 6%reduction in maximum Von Mises Stress and an 11%decrease in average main cutting forces.Radial ultrasonic vibration cutting effectively reduces vibrations caused by spindle rotation and tool holder inherent frequency by approximately 22%.Furthermore,the extreme difference(maximum minus minimum)of the original contour of the machined surface is reduced by about 23%.
The discipline of landscape architecture bears the important responsibility of building a beautiful living environment,inheriting the cultural lineage and maintaining the balance of the ecosystem.It has become the core issue and urgent task of landscape architecture professional construction to explore the cultivation mode of landscape architecture talents in colleges and universities and the way of teaching reform,and to construct the modularized curriculum system of landscape architecture majors with unique characteristics in colleges and universities.From the aspects of curriculum system,practical teaching system,talent cultivation system and reform and optimization strategies,the article researches and explores Ecology,Plan design,Engineering,Architecture and Art,the EPEA composite talent cultivation mode of landscape architecture,constructs the"five-in-one"talent cultivation system of EPEA professional module curriculum and multi-level and stepwise practical teaching,and puts forward countermeasures for the reform and optimization of EPEA compound talents cultivation in landscape architecture.It is expected to provide reference for the cultivation of innovative talents of landscape architecture specialty in local colleges and universities.
The analysis of membrane fouling in the advanced treatment system for boiler recharge water in a thermal power plant provides valuable insights into the operation of multi-water source reverse osmosis system.This study,considering water quality and the structure,composition and morphology of the polluted layer,investigates the operational effectiveness and membrane pollution characteristics of a multi-water source advanced treatment system in a thermal power plant.Additionally,the paper analyzes the effluent quality of the entire system.The results indicate that in the first stage,the primary pollutants consists of Fe hydrolysate,organic matter and Fe-P complex.Colloidal Fe emerges as a crucial factor causing a significant increase in membrane operating pressure.The second stage membrane is predominantly composed of inorganic pollutants such as CaCO3,Ca-Al and Ca-P,along with some humic acid and microbial contamination.
The design of indoor interaction space in universities for the elderly can create a good learning and interaction environment for the elderly and meet their needs for interaction space.Taking Jinan University for the Elderly and Jinan University for the Elderly Gaoxin Campus as examples,the article adopts the Semantic Differential method to evaluate the environmental factors of their interaction space and optimizes and designs their indoor interaction space based on the evaluation results.The results show that among the environmental factors affecting the interaction space for the elderly,the spatial function layout factor contributes the most,with a value of 28.927%,followed by the spatial environment factor and the aesthetic factor,with contribution rates of 24.551%and 16.118%,respectively;from the perspective of points,lines,and surfaces,this paper proposes design strategies for indoor interaction space in universities for the elderly,such as functional superposition,health and comfort,and place experience,and optimizes the interaction space in universities for the elderly with measures such as point node space-functional superposition,line node space-functional composite,and surface node space-place experience.
Plate evaporative water cooler has a wide application prospect in chemical and steel industries.The optimal design of its structure has important guiding significance for engineering application.This paper utilizes MATLAB to simulate the heat and moisture exchange process between cooling water,air,and spray water in a plate evaporative water cooler.By analyzing the influence of structural parameters(length,width,plate spacing and height to width ratio of the cooler)on the cooling performance of plate evaporative water cooler,the influence trend of structural parameters'change on outlet water temperature,outlet air enthalpy and cooling efficiency of evaporative water cooler is obtained.At the same time,the order of structural parameters'influence on performance indexes and the optimal structure sizes of water cooler are obtained.The results show that cooling efficiency of evaporative water cooler decreases with the increase of length,width and air channel plate spacing,and it increases with the increase of plate spacing of hot fluid channel and height to width ratio.The optimal structure sizes of the cooler are as follows when cooling water volume is 300 t/h:the plate spacing of hot fluid channel is 4.10 mm,the air channel plate spacing is 3.75 mm,the length of water cooler is 1.4 m,the width of water cooler is 1.75 m,and the height to width ratio is 0.75.
In the context of energy conservation and emission reduction,the development and utilization of new energy is crucial to national development.Phase change energy storage technology can solve the problem of mismatch between time and space of new energy.In this paper,a V-shaped structure metal skeleton is constructed.The finite element method was used to numerically simulate and analyze the melting rate,heat storage rate and local thermal non-equilibrium effects of the models of pure paraffin square cavity,paraffin square cavity with uniform structure metal framework,and paraffin square cavity with V-shaped structure metal framework.The results show that the addition of metal skeleton is conducive to the melting of phase change materials,and the effect of V-shaped structure metal skeleton is better;compared with uniform structure metal skeleton,V-shaped structure metal skeleton has a more obvious effect on improving the heat storage rate of phase change materials;in the early stage of model heat transfer,the local thermal non-equilibrium effect of the V-shaped structure metal skeleton is more obvious,but in the later stage of model heat transfer,its temperature uniformity is better.
The undersea tunnel is located in a state of high confining pressure and high water pressure,and there is unlimited water supply above it.Seepage and water inrush are easy to occur during the construction process.Therefore,adjusting the corresponding construction plan based on the prediction results of water inrush can reduce the probability of water inrush.Based on the Shantou Bay Undersea Tunnel project,this paper compares the results of water inflow in various tunnels from the analytic formula and gives the most applicable prediction formula for the project.At the same time,the results are used to carry out orthogonal test,and the three factors affecting the stability of the transition section are analyzed,the order of every factors affecting the two indexes of differences of crown settlement and water inflow is determined.The results show that the result from the Macastor Analytic Formula is more safe and close to the engineering survey data.It is also found that the total length of the engineering transition section has a significant influence on the stability of the interface of surrounding rock,but the influence of excavation method and excavation progress on it is not significant.When the length of the transition section is about 10 m,the transition section has a good effect on improving the stability of the interface of surrounding rock.When the length of the transition section is greater than 10 m,the improvement effect is not significant.
空间结构稳定性是保障结构安全主要因素之一,为评估空间钢结构在役期间稳定性及安全问题,提出一种基于突变理论的结构稳定性评估方法.根据结构健康监测系统历史应变监测数据,以应变速率为特解,反演得到结构非线性动力模型;基于突变理论建立空间结构应变速率尖点突变模型,推导出结构稳定性判据;运用主成分分析的方法,对历史应变监测数据提取特征值并降低维数,采用基于突变理论的突变级数法计算出结构突变级数值;以实际工程为例,对评估方法进行验证.结果表明:潍坊北站钢结构屋盖在役期间稳定性判别式Δ＞0,判别结果与实际运维情况一致;主成分分析压缩得到特征数据可有效降低数据维数;利用突变级数法可对空间结构稳定性实现综合评估.
水生植物是组成园林水景的重要素材,在丰富水景景观效果、净化水体、保持水体生态平衡、创造园林意境方面有重要作用.文章基于济南 6 处公园水生植物的应用现状,通过标准样方调查,采用聚类分析和层次分析评价法,综合评价其水生植物种类分布、开发应用、观赏价值等.结果表明:济南主要水生植物有 32 种,隶属23 科 28 属,以挺水植物应用为主,浮水、漂浮、沉水植物应用较少;2 种评价方法均将 32 种水生植物划分为 4类,其中有 4 种为景观效果最好的类别,而 7 种为景观效果较差的类别;相比于层次分析法,聚类分析能够体现水生植物各项指标的表现特征,更具客观性,与实地调查结果吻合度高.
