Advanced Materials Research Vols. 317-319

Abstract: Currently when the domestic concrete pump is pumping, the piston of master cylinder may hit the cylinder or not travel enough displacement; the travelling rules in different conditions have been not found yet. In this paper, an open circuit hydraulic control system is researched by simulation software AMESim, pumping circuit and dividing circuit of the system are modeled and simulated. The simulation results are compared with experimental results to illustrate the accuracy of the modeling. Then the relationship between travelling displacement of the piston and the factors, such as location of trigger port, different diameter of damping u-tube, is analyzed. In the end, a set of reasonable design parameters of the hydraulic system is proposed.

Abstract: This paper offers many advantages of smoke-free low-noise environment-friendly ground flare in comparison to traditional elevated flare in performance and technology, briefly summarizes the research status and development trends of ground flare at home and abroad. This paper makes a more detailed analysis and description focusing on the application of smoke-free low-noise environment-friendly ground flare in petrochemical industry. At the premise of safety, reliablity and environmental protection, how to study the new ground flare, in aspects such as dealing capability, combustion efficiency and control mode of flare burner, is the major direction of petrochemical waste gas treatment device in future development.

Abstract: The domestic 25-ton truck crane has the problems of high system pressure during steady slewing and great hydraulic impact when slewing motion starts and brakes. So the simulation model of the slewing hydraulic system and the core hydraulic components was constructed by AMESim. The flow areas of throttling grooves on the valve rod of the directional control valve were calculated by Matlab and converted into text files, which were imported into the simulation model. To get the load parameters of slewing system in different work conditions, an experiment on real truck crane was performed. Then the problem work conditions recurred in the simulation, which showed the veracity of the simulation model. Based on the simulation model an improving method was presented and simulated and the simulation results showed that through the improving method, the system pressure and the hydraulic impact could be efficiently reduced.

Abstract: The composite lining model of railway tunnel is set up and then simulation test is presented by non-contact detection with the simple detection equipment of ground penetrating radar (GPR) to study the main technique parameters of the equipment. The results show that the lining can be detected by the way, and the quality of GPR scan obtained in the simulation test decreases with the detection distance increasing. In the GPR scan obtained when keeping ground-coupled shielding antenna of 400MHz 20cm away from the ground(the distant from the bottom of GPR antenna to the surface of lining specimen), a variety of work conditions that has been preset in the experimental design can be identified, moreover, the location and range of both uncompacted backfill and cavity behind the lining etc. approach those that can be get when the antenna sticking to the lining, thus providing satisfactory qualitative interpretation of GPR scan. In addition, the deviation range of GPR non-contact detection is close to that when the antenna sticking to the lining, thus ensuring the detection value accuracy of lining thickness.

Abstract: The detection equipment for the state of railway tunnel lining is a vehicle-mounted complex equipment which is supported by the special purpose vehicle of railway and integrates with various sophisticated detection device including laser clearance measurements, ground penetrating radar (GPR), laser imaging device of the lining surface, video monitoring system, therefore it can be efficient, accurate and comprehensive completion of detection of operating tunnel lining. In this paper according to relevant norms, standards for assessing the state of operating railway tunnel and current detection technologies of tunnel lining, the functions and components of detection equipment are determined and the main performance parameters of device and the key technologies are deeply analyzed and studied, to speed the development of equipment and provide the necessary technical support.

Abstract: The performance of modern printing machine depends heavily upon the raster image processor (RIP) whereof it is equipped with. The conventional digital halftoning technology used in RIP is characterized as error diffusion, which is suitable for imaging machines with low resolutions, often resulting in correlated artifacts and transient edges. We report an innovative stochastic halftoning method without error diffusion for RIP by using an optimized random number generator (RNG). The RIP system we proposed has simple computation and stochastic features of ink spots. This research is supportive of enhancing raster image quality oriented to printing machines with high physical resolutions.

Abstract: In the process of low-permeability sandstone reservoir exploitation, stress sensitivity takes place with the effective stress rises gradually, which will cause permeability decline. Allowing to the condition of in-situ stress, the study and experiment on the rock core in Jilin oil field Fuxin326 oil layer are presented. The experimental results show that the stress sensitivity of this oil layer is small; the regularity of permeability changes is in accordance with exponential function. The stress sensitivity of high permeability core is larger than that of low permeability core. Moreover, experimental and theoretical analysis shows that low permeability core has a larger permeability loss than high permeability core in loading and unloading process where elastic plastic deformation of rock will happen, which is the major reason that permeability loss can not return completely.

Abstract: Water samples were collected in the northern, eastern and southern tidal creeks of Chongming Dongtan in January, 2009. The samples were passed through 0.45μm pore size GF/C glass fiber membrane and colloid was isolated by mini tangential flow ultrafiltration (TFF) with ultrafiltration membrane pore-size of 1kD (1kD=1 000 Daltons). Then the content of organic carbon was tested by TOC II. Results show that the contents of dissolved and colloidal organic carbon (DOC and COC) in the northern creek are higher than the eastern and southern tidal creeks of Chongming Dongtan, and the concentration of DOC decreased from high tidal flat to low tidal flat. Hydrodynamic and vegetation are the important factors to affect the content of COC in tidal creek water of Chongming Dongtan.

Abstract: With the development of networks and wideband technology, Next Generation Network (NGN) evolves into integrated transmission network of the multimedia information which including data, voice, image, the real-time tasks, etc. The traditional IP network provides only "best-effort" service and cannot meet the needs of multi-media applications and the different demands of a variety of users for network transmission quality. On the basis of a detailed analysis to Differentiated service (DiffServ) model and the characteristics of MPEG-4 encoding, the QoS control strategy of video streaming in NGN is proposed. That is a QoS control strategy which uses priority of Inter-Frame combining with DiffServ model in network congestion. Simulation and testing results show that the strategy can improve the transmission quality of the video stream effectively in the case of limited bandwidth.

Abstract: The load time history signal of engineering vehicle is usually polluted by various nonstationary and stationary noises in the field test. An approach based on wavelet transform (WT) and fractal dimension (FD) is proposed in order to improve the adaptability and efficiency of denoising. This method initially decomposes the original signal into detail and approximation space in the WT domain by WT-based multiresolution decomposition. The short-time fractal dimension of detail coefficient is calculated at each scale. After the application of the binary processing to the short-time fractal dimensions, the locations where the thresholding of the detail coefficients has to be executed are ensured. The desired load signal is provided by applying WT-based multiresolution reconstruction to the processed detail coefficients and the unprocessed approximation coefficients. The proposed method is applied to an actual load time history signal of engineering vehicle. And the performance of this method is compared with that of the WT-based hard thresholding denoising method. The results show that this method is an alternative way to process the load time history signal of engineering vehicle.