Advanced Materials Research Vols. 341-342

Abstract: This paper presents effects of silicon carbide SiC powder concentration on micro EDM parameters on average surface roughness (R_a). The aim is to achieve minimum R_a value on titanium alloy (Ti-6Al-4V) machined with tungsten electrode for various level of concentration of SiC powder and discharge energy (E). By using two-parameter and four-level factorial design of experiment sixteen experiments were conducted. The measured surface roughness values were analyzed with input parameters using by Design Expert software. The minimum R_a value obtained was 0.75 µm for 16.8 g/L SiC powder concentration and 57.8 µJ energy discharge. The analysis of variance revealed that powder concentration is the most influential parameter.

Abstract: Main restriction for achievable material removing rate and simultaneously high quality parts in grinding process is the high specific energy requirements and consequently thermal damage to workpiece. In this work, a sequence of experimental tests were performed focused on grinding parameters including wheel speed, workpiece feed rate and depth of cut. Previously developed grindiable thermocouples were utilized to measure grinding surface temperature in each experiment. Feasibility of the grindable thermocouples in workpiece surface temperature measurement in the grinding process was investigated. Then, a 2-D finite element thermal model was created using ANSYS code based on the experimental data for numerical investigation. The model was used to predict grinding surface temperature in conditions of the experiments. A comparison between experimental and numerically predicted results for grinding surface temperature shows good agreements within an acceptable margin of error. The absolute average of errors is equal to 6.6%. Therefore, the proposed grindable thermocouple technique can be used in measurement of workpiece surface temperature and study of thermal aspects of grinding process.

Abstract: Three-dimensional visualization of medical imaging technology uses two-dimensional medical image sequences to reconstruct three-dimensional model, providing the physician with intuitive, comprehensive, accurate information about the focus and normal tissues, is currently a hot research field of medicine. This essay makes a comparison between the two currently popular algorithms – surface rendering algorithm and volume rendering algorithm, with its focus on the introduction of MC algorithm, meanwhile achieves the integration of three types of improved MC algorithm, completes a high-precision, high-efficiency surface rendering process based on .MFC and OpenGL technologies.

Abstract: In this paper, we propose an aurora classification method using a multi-level feature representation aimed to capture both global and local texture information, and to reduce the feature space dimension substantially. First-order and second-order statistics are computed for an input image and its low-frequency scaled images at three lower levels obtained using wavelet decomposition. The features include gray level distribution, co-occurrence matrix features, and run-length matrix features. A support vector machine (SVM) classifier was trained and tested on a Chinese Arctic Yellow River Station dayside aurora image dataset. Classification performance was evaluated and compared with those of k-nearest neighbor (KNN) classifiers and back-propagation neural networks (BPNN). To explore the possibility of using a smaller feature space, we used a Minimum-Redundancy Max-Relevance feature selection strategy. The result shows that there is only indistinct performance decrease by reducing the feature vector from a total of 88 to the most discriminatory 38 features. This proves that our multi-level feature representation is very robust.

Abstract: Based on the three dimensional surfacelet transform, a novel multisensor video fusion algorithm is proposed, in which, multiple frames of input videos are regarded as special three dimensional signals and fused as a whole rather than frame by frame. Meanwhile, selection principles for different subband coefficients are discussed in detail. Experimental results demonstrate that the proposed algorithm outperforms the traditional individual-frame-based and motion-based methods in spatial-temporal information extraction as well as in temporal stability and consistency. In addition, it does not require the motion target detection pre-step and is easy to implement.

Abstract: In this paper we propose a method for CBIR based on the combination of texture, edge map and color. As texture of edges yields important information about the images, we utilized an adaptive edge detector that produces a binary edge image. Also, using the statistics of color in two different color spaces provides complementary information to retrieve images. Our method is time efficient since we have applied texture calculations on the binary edge image. Our experimental results showed both the higher accuracy and lower time complexity of our method with similar related works using SIMPLIcity database.

Abstract: This paper introduces the carbon fiber and carbon fiber reinforced material performance, and expounds the molding process and introduces the current carbon fiber composite application in sports equipment.

Abstract: Semi-solid metal processing (thixoforming) is a potential forming technology, which can realize near-net-shape forming process with good quality in one forming step. In this study, semi-solid casting (thixocasting) was used to form the auto box-like. Based on Power Law Cut-Off (PLCO) model and finite element code Procast software, the thixocasting process was modeled and simulated. The impact of main process parameters such as initial billet temperature, ram speed as well as die temperature on the thixocasting process was studied. The results show that thixocasting process can be used in forming auto box-like.

Abstract: Green composite made from ramie fabric and polypropylene (PP) is a kind of recyclable and environmental friendly material. Ramie fiber tows have relatively good mechanical properties comparing with other bast fibers, and hence the fabric woven by ramie yarn shows excellent in-plane mechanical behaviors. PP can be fully recovered and recycling used for its thermoplastic character. Ramie fabrics reinforced by PP have better shape formability and maintenance. In this paper, we proposed a plain weave in sample dobby loom, and reinforced four laid-layers together by PP particle through hot pressing. The mechanical behaviors of the ramie-PP composite were tested by MTS-810 Material Testing System in weft and warp directions separately which were essential parameters to the following topology optimization in finite element analysis (FEA) software. A body of eco-power automobile consisting of shell and chassis was original designed in Pro/E^® Wildfire 5.0. For the chassis is the main bearing structure, it is an important part in the eco-power automobile body and was chosen to be topology optimized. Fiber volume fraction and structure optimization of the chassis model are evaluated and simulated to guide the material formation of manufacture progress.

Abstract: Geopolymer requires an alkaline activator to induce it pozzolanic property and to accelerate the geopolymerisation process. The geopolymerisation process occurs due to the mixing of fly ash, sodium silicate and sodium hydroxide as the alkaline activator, which produces aluminosilicate gel that acts as a binder. As such, the ratios of fly ash to alkaline activator and Na₂SiO₃/NaOH play an important role in obtaining desirable compressive strength; the concentration of NaOH used in this study was 12 M. Different ratios of fly ash to alkaline activator (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0) and Na₂SiO₃/NaOH (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0) were investigated in order to determine the maximum compressive strength. The alkaline activator was mixed with fly ash with different ratio as mentioned above and the samples were cured at 70°C for 24 hours and tested on the seventh day. The maximum compressive strength was obtained when the ratios of fly ash to alkaline activator and Na₂SiO₃/NaOH were 2.0 and 2.5 with compressive strength 73.86 MPa.