Search

Operation parameters restrict the performance of hydrocyclone in offshore platforms. Based on the computational fluid dynamics (CFD) software Fluent and the similarity parameter criterion experiment, the numerical simulation of the separation flow field and separation efficiency of hydrocyclone at different feed solid concentration was carried out, taking short circuit flow into account, a new correcting separation size equation was derived according to the locus of zero vertical velocity (LZVV) method. The results shown that when the feed solid concentration was more than 40%, the peak value of tangential velocity decreased and the increasing amplitude of underflow pressure drop will decrease compared with the increasing amplitude of overflow pressure drop, the region with the highest turbulence intensity increased when the concentration was more than 40%. The total separation efficiency and the feed solid concentration showed a positive correlation at 0 ~ 40%, and the increase in total separation efficiency was the smallest when it was higher than 40%, with a value of 0.63%. There was a large difference between the values of d50c* and d50c while the feed solid concentration was 50%. From the above results, it could be concluded that the optimum feed solid concentration ranges were 0 ~ 40%. The new correcting separation size equation could be used in the range of 0 ~ 40%. This study could have certain guiding significance for the field application of the offshore platform desanding hydrocyclone.

PM2.5 is a class of airborne particles and droplets with sustained high levels in many developing countries. Epidemiological studies have indicated that PM2.5 is closely associated with the increased morbidity and mortality of lung cancer in the world. Unfortunately, the effects of PM2.5 on lung cancer are largely unknown. In the present study, we attempted to explore the role of PM2.5 in the etiology of NSCLC. Here, we found that long-term PM2.5 exposure led to significant pulmonary injury. Epithelial-mesenchymal transition (EMT) and cancer stem cells (CSC) properties were highly induced by PM2.5 exposure. EMT was evidenced by the significant up-regulation of MMP2, MMP9, TGF-β1, α-SMA, Fibronectin and Vimentin. Lung cancer progression was associated with the increased expression of Kras, c-Myc, breast cancer resistance protein BCRP (ABCG2), OCT4, SOX2 and Aldh1a1, but the decreased expression of p53 and PTEN. Importantly, mice with IL-17a knockout (IL-17a-/-) showed significantly alleviated lung injury and CSC properties following PM2.5 exposure. Also, IL-17a-/--attenuated tumor growth was recovered in PM2.5-exposed mice injected with recombinant mouse IL-17a, accompanied with significantly restored lung metastasis. Taken together, these data revealed that PM2.5 could promote the progression of lung cancer by enhancing the proliferation and metastasis through IL-17a signaling.

This paper presents a study of a three-row opposed gripping mechanism made of bioinspired spiny toes. An insect Serica orientalis Motschulsky’s tarsal system was first described and studied. A compliant single spiny toe model was established assuming that the contact asperities were spheres. Following the single toe contact model, a spiny toe array’s contact model was then developed using asperity height’s distribution function. By studying the engaging and disengaging process of the single toe, the mechanical behavior of the toe and toe array were addressed. The toes as well as the arrays were manufactured via rapid prototyping. A customized apparatus using displacement-control method has been carried out to measure the pull-in forces and pull-off positions of the single toe and toe array under various compression conditions. Based on the understanding, a three-row opposed gripping mechanism with radial configuration for wall-climbing robots was designed and fabricated according to the mechanical behaviors of the toe and array. Using an opposed spoke configuration with 3 rows of 31 toes on each linkage array, the mechanism designed as a foot of climbing robots can vertically resist at least 1 kg of load on rough inverted surface, while the maximum normal load is as high as 31 N. The findings may provide a way in developing a high payload wall-climbing robot system for practical applications.

In order to study the internal flow field and oil-water separation mechanism of double cone hydrocyclone, based on fluid dynamics software Fluent, the effects of oil phase volume distribution, tangential velocity distribution, feed flow rate at different oil droplet sizes and fractional ratio at different oil concentration on the separation efficiency of the hydrocyclone were analyzed. The results show that the feed flow rate should be less than or equal to 3.5 m3/h to reduce the energy loss; The separation efficiency is the best when the oil droplet size is 1 mm–1.5 mm and the feed flow rate is in the range of 2.5 m3/h–3.5 m3/h; In order to achieve the highest separation efficiency, the split ratio should be 1.2–1.3 times of the inlet oil concentration. The research can provide reference for the separation mechanism and flow field characteristics of hydrocyclone.

Public data provided by the International GNSS Service (IGS) website shows that from 0:00 UTC on February 14, 2020, the power of the P(Y) code signal of some GPS satellites at the L2 frequency point has been increased significantly. An automatic analysis method of GPS satellite signal power sudden changes based on data from multiple ground stations is proposed. This method is based on the post-observation data of multiple ground stations and automatically analyzes the time of the sudden change in the power of the navigation satellite signal through computer software, so as to determine the satellite power enhancement period, and then analyze the availability of the satellite in the power enhancement state. The method can be applied to the analysis and research of the power enhancement effect of GPS system.

Traditional data processing thinking mode and technology cannot meet the needs; big data technology is entering our life with an irresistible trend. Based on the analysis of the characteristics of e-commerce user data in the context of large data, this paper elaborates on the process of e-commerce user data mining in the context of large data. Finally, the Apriori algorithm is applied to mine e-commerce user data. The experimental results show that the use of Apriori algorithm can make an e-commerce platform more accurate marketing and commodity recommendation.

With the rapid development of rural e-commerce, users will produce a large amount of disordered original log data on the platform. In order to give full play to the user data value of agricultural e-commerce, this paper combs the concepts of big data and user data of agricultural e-commerce, and presents the user data analysis service and application system architecture of agricultural e-commerce based on big data technology, so that big data can be used in agriculture. The application value in the field of Commodity E-commerce has been fully embodied, which has played a role in promoting the further development of e-commerce.

Electric vehicle charging station (EVCS) site selection occupies a prominent position in the development of the electric community to solve the hard problem of Electric Vehicle (EV) charging. However, two critical issues have not been solved by the existing research. Firstly, the scope of EVCS site selection only considers the whole city, which deviates from the actual situation. Secondly, the uncertainty and hesitation of decision information is not well expressed. To handle the above problems, this paper builds a comprehensive EVCS site selection decision framework for Residential Communities (EVCSRC) with triangular intuitionistic fuzzy numbers (TIFNs). First of all, the distinctive index system of EVCSRC site selection factors including economy, social, environment, planning and feature portrait of residential communities is established. Then, the TIFNs is utilized for decision makers (DMs) to express the indeterminate information. Furthermore, a fuzzy Vlsekriterijumska Optimizacija I Kompromisno Resenje (Fuzzy-VIKOR) is approach is utilized to rank the alternative EVCSRC sites. Finally, a case of Beijing is studied to demonstrate the validity of the proposed site selection framework. The result shows the EVCSRC site located at Sijiqing community in Haidian district should be selected as the optimal site. This paper presents a feasible and easy-to-use decision-making framework for investors.

Autophagy serves to eliminate damaged proteins and organelles under normal physiological conditions and can be accelerated by pathological stress, possibly as a cytoprotective mechanism. Brief periods of ischemia (ischemic preconditioning or IPC) can reduce neuronal death in response to subsequent severe ischemic insults. Ischemic preconditioning also induces autophagy, but the contribution of autophagy to IPC-associated neuroprotection remains unclear. We investigated the contribution of autophagy to IPC-mediated neuroprotection in rats subjected to ischemic spinal cord injury. Fifty adult rats were randomly assigned to either (1) a sham group receiving anesthesia and surgical preparation (n=5), (2) an ischemia/reperfusion (I/R) group (n=20) subjected to 0.5 h ischemia followed by 3, 6, 12, or 24 h reperfusion, (3) an IPC group receiving three cycles of 5 min ischemia followed by 5 min of reperfusion (n=5), or (4) an IPC+I/R group (n=20). Hematoxylin-eosin (HE) and immunohistochemical staining were performed to evaluate spinal neuron survival in the four treatment groups. Autophagic activity was investigated by electron microscopy and by immunohistochemical and Western blot analyses of the autophagosome marker LC3-II and the autophagy-associated BH3 protein Beclin-1. Changes in Bcl-2/Beclin-1 complex association and Bcl-2 phosphorylation (p-Bcl-2) were examined by co-immunoprecipitation and Western blot analyses. In the I/R group, LC3-II was significantly elevated after 3h of reperfusion, but declined significantly by 24 h. At 24 h, I/R rats exhibited extensive spinal damage and decreased neuronal survival. In the IPC+IR group, neuronal death was reduced and expression of LC3-II sustained throughout the 24 h reperfusion period. In the I/R group, expression of (inactive) p-Bcl-2(Ser70) was increased significantly during reperfusion and was accompanied by dissociation of the Bcl-2/Beclin-1 complex and increased Beclin-1 expression. Preconditioning inhibited these changes in p-Bcl-2, Beclin-1, and Bcl-2/Beclin-1 complex expression. Ischemic preconditioning appears to sustain the beneficial effects of autophagic lysosomal degradation during I/R while inhibiting autophagic cell death.

We found that the change of overvoltage has more influence than that of the gate signal voltage on DCR. The lower DCR and higher detection efficiency can be achieved by choosing the voltage appropriately.

The present era is an information and Internet age, with peoples life more and more inseparable from it. Through the network platform, we can study, do some reading and shopping. There appeared a new term Internet of Things after the time of Internet. Different from network, it is a kind of information technology, has driven the development of network and is the trend for the future network, so its architecture and technical research attach great importance to the all fields. This paper analyzed the problems in the aspects of architecture and techniques.

With the quick development of technology, the Internet of things is becoming one of the most important components in our society. The Internet of things can make everything connected with Internet, and it is convenient to recognize and manage. In the process of recognizing the things in the Internet of things, it will appear irrelative and vague data, and we could not analyze and identify effectively. Focusing on the work of analyzing data, we propose PCA algorithm based technology in this paper, and apply it into works in the Internet of things. Through the theory and experimental results, we can prove that the technology we propose can select main information from prolix data, and complete the recognition works.

Objective To evaluate the long-term outcomes of ridge expansion technique in dealing with horizontal bony insufficiency of alveolar ridges for implant placement. Materials and methods During the period 2004–2009, 168 patients with width insufficiency of alveolar ridges were treated using the ridge expansion technique to obtain an improved bony base for implant placement. Depending on the severity of width insufficiency, the surgical procedures were classified into two groups: ridge expansion alone (Group 1) and ridge expansion in combination with guided bone regeneration (Group 2). After 4–6 months of unloaded healing, the implants were restored. The patients were followed up until 2013 with clinical and radiographic examinations. Results Among the 168 patients, 11 patients underwent a fracture of labial/buccal bony plate during surgery, which was corrected by changing the procedure into bone grafting, yielding a surgical failure rate of 6.5%. In the remaining 157 patients successfully treated by ridge expansion alone or in combination with GBR, 226 implants were simultaneously placed as planned. No implant failed over 2.8 years (6 months to 8 years) of follow-up, yielding a cumulative implant survival rate of 100% in each group. Six implants in Group 1 and 4 implants in Group 2, although osseointegrated and in function, did not fulfill success criteria: Cumulative implants' success rates were 93.2% in Group 1 and 95.6% in Group 2. The mean marginal bone losses during the first year in Group 1 and Group 2 were 0.69 and 0.43 mm, respectively, followed by an annual loss of ~ 0.06 and 0.07 mm, respectively, in the following years. No clinical parameter was abnormal. Twenty-two (10.4%) implants were exposed to peri-implant mucositis, whereas 19 (11.0%) implant-supported restorations were involved in prosthetic complications. Conclusions The preliminary results of this retrospective study indicate that ridge expansion alone or in combination with GBR can be considered an effective and safe procedure for treatment of width insufficiency of alveolar ridges on the purpose of implant application.

Sparse representation-based classification (SRC) method has demonstrated promising results in face recognition (FR). In this paper, we consider the problem of face recognition with occlusion. In sparse representation-based classification method, the reconstruction residual of test sample over the training set is usually heterogeneous with the training samples, highlighting the occlusion part in test sample. We detect the occlusion part by extracting a mask from the reconstruction residual through threshold operation. The mask will be applied in the representation-based classification framework to eliminate the impact of occlusion in FR. The method does not assume any prior knowledge about the occlusion, and extensive experiments on publicly available databases show the efficacy of the method.

With the rapid development of domestic amusement industry, a design of racing simulator controller are put forward. Make full use of the advantage of ARM Cortex-M3 processor in its area, combine with the MD2 controller which is a professional controller of the hydraulic system, through the hardware and software research of each module, a racing simulator controller are designed to develop a racing simulator. The players can find the excitement from this simulator which is close to the real racing.

This paper has put forward a novel system framework of adaptive user interface development for cartographic visualization system. Based on the research on its software architecture, we described each module in this framework and discussed in detail the software development process and techniques for adaptive user interface development. Finally, a prototype system of adaptive user interface development was implemented based on this framework.

This paper proposed a robotic elbow joint intelligent control method based on radial basis function neural network (RBF_NN), which is capable of tracking the desired trajectory with high accuracy. Dynamics of robotic joint and design of the RBF-NN-based controller is formulated. A lot of simulations are conducted, and the simulation results have shown that the control strategy is feasible and efficient.

According to the environment and work styles, the underwater monitoring devices can be divided into three type, fixed monitoring device, the floating monitoring device and mobile monitoring device. Floating monitoring platform is a new type of monitoring device of the floating monitoring device, which is mainly used for underwater video monitoring of pool. as the floating platform monitoring in water motion and hydrostatic characteristics are closely related, the influent of counterweight, weight distance and floating body diameter of the structure parameters on its hydrostatic characteristics and the natural periods for roll, pitch and heave should be considered, In this work, the floating body diameter influent most, the counterweight followed, and the structure parameters have different influence on the natural periods for roll, pitch and heave , it need to be analyzed according to the concrete structure parameters.

In order to enhance the roads maintenance, a number of weigh-in-motion (WIM) systems are used in the high way to collect the weight of every vehicle pass by, but normally the outcome is rough. The one important reason of this problem is that lots of complex low-frequency noises exist in the weighing signal, which can not be filtered by the Fourier series analysis. In this paper, firstly we apply the de-noising method via thresholding of wavelet coefficients to purify the signal, and then we propose an evolving wavelet thresholding method for the WIM system using evolutionary programming (EP), further we evolves the best threshold by this method and improve the weighing signal processing. Finally, we use our thoughts to model a simulated WIM signal de-nosing system and experimental results shows that this novel system provides more accurate data compared to other existing analyzing measures for weighing signal.

There exist numerous image retrieval systems perform a fast similarity search in the image databases, but the quality of the outcomes provided by histogram-based image search is usually rather limited. One of the reasons is that histogram-based systems only support some form of global similarity using the whole color histogram as one vector. Meanwhile there is more information in a histogram than the distribution of samples resp. colors. In this paper, we first introduce some generic similarity search methods in the image database and then use them to form a generalized model that can adapt various transformations. Farther on, in virtue of the effectiveness of the evolutionary computation and based on the model, we construct a fitness function using the wavelet transformation to optimize the image similarity search by the particle swarm optimization. The results of our approach present a much better quality than other existing similarity search measures.

This paper compares the similarities and differences between multilayer perceptrons (MLPs) and radial basis function (RBF) neural networks, proposes the method of how to decompose a large-sample and multiple-category training set into many small-sample and two-class training subsets. Further-more, we take single-hidden-layer perceptrons and RBF networks as the basis units to construct combinative neural-network-based classifiers. This kind of combinative classifiers has higher classification accuracy and better generalization performances than their component parts. The results for recognizing the handwritten numerals and English letters show that the presented combinative classifiers are quite effective for solving the large-sample, high-dimensional and multiple-category classification problems.