Advanced Materials Research Vols. 482-484

Abstract: To achieve the laminar flow filling pattern in squeeze casting processes, many literatures [1-4] have reported that ideal velocity of liquid metal passing through the ingate should be between 0.1 – 0.5 m/sec. John Campbell [1] reported that liquid metal front speed velocity should be 0.4 m/sec in order to eliminate the gas porosity inside the casting. However, such slow speed requires the higher temperature of liquid metal and die. This results in not only the longer cycle time but also a coarser microstructure of the casting. In addition, the sample castings used in the literature are simple form castings which do not reflect the real castings used in daily life. In this study, the indirect squeeze casting processes is adopted to cast a motorcycle’s component originally produced by a high pressure die casting process. Based on shape and dimensions of the casting to get the real casting out for the mass production, melt’s speed must be higher than the level reported by the literatures (around 1 m/sec). As a result, a fully laminar flow may not be achievable. This is confirmed by the primary study of the process parameters and tooling design using the casting process simulation. However, by clinging on the two principles of the squeeze casting processes; (1) minimizing the amount of entrapped air by slowly fill the cavity and (2) reducing the amount of solidification shrinkage by pressurized solidification; the casting from two processes will be casted in order to compared the micro-structure and mechanical properties.

Abstract: Gabor feature is one of the features which have been used for texture classification. In this paper, we propose a novel fabric detect detection scheme based on Gabor filter and PCA. The fabric image is split into image blocks, and then different Gabor filter banks are applied into each image blocks. A feature vector is generated by concatenating all the Gabor features with different directions and scales for each image block. Principal component analysis (PCA) is adopted to reduce the dimension of the Gabor feature vector. In the end, SVM can classify each image block as non-defective and defective. Experimental results demonstrate the efficiency of our proposed algorithm. Because of its simplicity, online implementation is possible as well.

Abstract: By one-step co-electrodeposition Hemoglobin (Hb) and Au nanoparticles-chitosan (Au NPS-Chi) nanocomposite film on carbon ionic liquid electrode(CILE), the Hb immobilized with Au NPS-Chi nanocomposite film was stable and retained its functional activity. The results of cyclic voltammetrys showed a pair of well-defined and quasireversible redox peak of Hb with the formal potentials of −0.545V (vs.SCE) in 0.1 mol/L pH 7.0 PBS; a linearity range for determination of H2O2 is from 0.4 to 208.4μmol/L with a detection limit of 0.12 μmol/L (S/N=3). As a results, the one-step co-electrodeposition and the promising feature of nanocomposite could serve as a versatile platform for the fabrication of electrochemical biosensors.

Abstract: The motion vector (MV)-based steganography embeds the secret messages by modifying the motion vectors. So the traditional video steganalytic schemes cannot detect the presence of the hidden messages by MV-based steganography. In this paper, a novel calibration-based steganalytic scheme against MV-based steganography is presented. The features are derived from the shift differences between the original and calibrated MVs, and then the feature vector is constructed. Using the extracted feature vectors, the support vector machine (SVM) is trained to detect the presence of stego videos. Compared with other features, the proposed features have better performance even with the low embedding strength.

Abstract: Experiments were done to the same car with engine capacity of 1.6 liter on three typical road conditions in Shenzhen for emission characteristics of CO、HC and NOx with SEMTECH-DS manufactured by Sensors Company in USA. Through analysis on the experimental data it is indicated that emission factors with the measurement unit of g/km produced inflection points at the vehicle speed of 7.5～10 Km/h, and its variable rate is big at low speed interval and stable at high speed interval; average emission factors of CO and HC for car running in secondary city main roads is two or five times than those in city main roads; emissions of CO and HC of car at idle and low speed conditions take higher proportion.

Abstract: The existing old SPD(Surge Protection Device) test systems have following defects: they are isolated computer systems; when enterprise management applications or processes change, they can not respond in time to deal with the diversifications. To solve these problems, firstly, this paper analyzes the agent and web service-based lightning protection testing system architecture; secondly, this paper analyzes the architecture of SPD automatic test system; Finally, we designed and implemented the agent and web service-based SPD test system, the practical application show that the system overcame the shortcomings of old systems, integrated with other systems through the agent and web service architecture, avoided forming information silos, was smart to respond to the diversifications of enterprise management applications or processes.

Abstract: For heat exchanger tube of steam generator, the relation between heat exchanger tube and fluid is typical fluid-structure interaction problem. Flow induced vibration has been found so far to be responsible for fatigue damage and failure of steam generator tubes, which will result in large economic loss and radioactive pollution. So the steam generator tubes are the weakest link in the primary coolant loop. Based on the synthesis of all sorts of factors influencing the dynamic characteristics of steam generator heat transfer tubes, establishing the heat transfer tube model, research on the weakening effect of fluid hole on fluid, the natural frequencies of the heat transfer tubes are analyzed under different fluid holes and fluid hole distance by numerical simulation.

Abstract: Microcapsules of jasmine oil with β-cyclodextrin wall were prepared that can sustain the release of the fragrance.This study examined the morphology, structures and partied size distributions. The thermal properties of the microcapsules were investigated by TGA and the formation was characterized by FTIR. The morphology of microcapsules was examined. The experiments showed that β-cyclodextrin could efficiently improve the thermal stabilities of jasmine oil.

Abstract: Based on the characteristic of English for mechanical engineering (EME) curriculum, an analysis is made of the EME teaching situation and learners’ requirement, and then the EME teaching practice is researched from the respects of teaching materials selection, acquisition of vocabulary, analysis of long complex sentence, training of students autonomous learning and diversity of teaching methods in order to well cultivate compound talents needed in the new century.

Abstract: The experiment on four factors (bending angle, bending radius, tangent edge sliding cutting angle, operating width) that affect the single-pole unit width twist of rotary-broken universal blade is done using orthogonal experimental method.The paper respectively set up the function operations of single-pole unit width twist and bending angle, bending radius, tangent sliding cutting angle, and single-pole blade width according to experimental results. By these function operations, the paper analyze the value and scope of various factors in order to minimize the single-pole unit width twist under the conditions of rotary experiment.