Applied Mechanics and Materials Vol. 421

Abstract: This paper discusses the issues of modelling and smart computer support for low-pressure nitriding aimed at achieving more effectively the compatibility between the actual post-treatment properties of a material and the designed properties, which will contribute to improved repeatability of the processes. The principal objective of the experiment was to acquire better understanding of the cause and effect relationship of the low-pressure nitriding processes and to develop the methodology of designing functional and effective processes of low-pressure thermochemical treatment, using effective computational methods. The paper proposes a method of steel classification based on its chemical composition and a model used to forecast the properties of material after low-pressure nitriding, based on the artificial neural networks.

Abstract: Geopolymer is a new binding material produced to substitute the ordinary Portland cement (OPC) function as a binder in concrete. As we know, different types of geopolymer will have different properties. In this research, the different types of geopolymer raw materials had been studied in term of microstructure. Different type of materials which is fly ash (class F) and kaolin had been mixed with alkaline solution consist of sodium silicate and sodium hydroxide with suitable geopolymer raw material to alkaline activator and sodium silicate to sodium hydroxide ratios. The geopolymer samples with different types of raw material were then cured at a temperature 70°C for 24 hr and maintained at room temperature until the testing was conducted. After the geopolymers were aged for seven days, the testing was conducted.

Abstract: This research focuses on a study of the strength of concrete with ceramic waste as coarse aggregate and quarry dust as fine aggregate. The sources of ceramic waste and quarry dust are obtained from the industrial in Malaysia. Presently, in ceramics industries the production goes as waste, which is not under going the recycle process yet. In this study an attempt has been made to find the suitability of the ceramic industrial wastes and quarry dust as a possible replacement for conventional crushed stone coarse and fine aggregate. Experiment were carried out to determine the strength of concrete with ceramic waste coarse aggregate and quarry dust fine aggregate to compare them with the conventional concrete made (with crushed stone coarse aggregate). From the results show that compressive strength of concrete with quarry dust as aggregates is the highest with 30.82 MPa with density 2251.85 kg/m³_. This show, ceramic waste and quarry dust can be alternative aggregate for comparable properties.

Abstract: Properties of oil palm trunk fiber reinforced cement composite were investigated in this study. Oil palm trunk fiber was used to improve the properties of cement composite. It was found that increasing in oil palm trunk fiber content up to certain percentage increase the compressive strength and decrease the density of cement composite. Besides, the study also found that additional of excessive of oil palm trunk fiber in cement composite decrease the compressive strength and continues to increase the water absorption and moisture content hence decrease the density. From this study, it was found that 2 wt. % of fiber content was the optimum fiber content to give the highest compressive strength of 38.61 MPa.

Abstract: The oxidation behavior of steel and pure copper has been investigated in the temperature range of 500-700°C at various oxygen pressures. The rate of oxidation was measured using thermal gravimetric apparatus (TGA). The morphology, composition and structure of the oxide scale were determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

Abstract: The atmosphere&vacuum-catalytic cracking integrated unit of a petrochemical enterprise in Hangzhou can not be tested for continuously producing 35 sets of pressure vessels. This thesis assesses the three main parameters (probability of failure, failure result and risk of failure probability and result) of the system through FBI technology, analyzes the potential failure mode and probability in this system and confirms the risk of failure via calculating failure result. This thesis shows the testing strategy suitable for this device based on failure mode, failure probability and result and puts forward scientific and proper testing cycle based on risk level of equipment to ensure the depth and rationality of overdue testing work and improve the reliability of safe and stable operation of device for the system before the next maintenance cycle.

Abstract: By measuring the thickness of the nacreous layer, pearl optical coherence tomography (OCT) images are now increasingly used in identification and characterization. An approach to automated thickness measurement of pearl OCT image has been reported in this paper. A Total Variational (TV) Model filter has been used to remove noise in images. After the image filtering, edges are detected by self-adaptive Canny operator. In the end we used circle fitting technologies to archive the goal of automated thickness measurement. The experimental results show this approach is accurate and adaptable.

Abstract: The requirement of the accuracy of microscopic measurements becomes more and more high, and traditional methods have been unable to meet the demands. Digital image deconvolution techniques are applied in microscopic measurement. By fabricating a pointolite, the point spread function of the optical system is measured, and then the geometric blurring in traditional microscopy is removed by using the maximum likelihood estimation algorithms and iteration threshold segmentation algorithms. The technique is applied to measure the total content of perlite and spheroidal graphite in spheroidal graphite iron accurately and easily, and then to measure the area of a scratch scaled in 10 microns on a medical department of orthopedics plates. The technique makes great sense in the development of corresponding measurement.

Abstract: Collision between the contact probe and the measuring part will occur easily when conducting geometric measurement of the curved parts with complex surface shape. To solve the security problem of geometric measurement, a generation method of collision-free measurement path was proposed. First, collision check was simplified into the calculation of line-surface intersection. Meanwhile, we used bounding box method and triangulation method as auxiliary tools. Then, when dealing with collision avoidance, we utilized bounding box in parametric directions to avoid collisions caused by neighboring surfaces. In addition, we used parameter extreme points to avoid collisions caused by the measuring surface itself. At last, path simulation of a complex curved part verifies the security of the path generated by means of the method proposed in this paper.

Abstract: The fluid dynamics method combined with a low-speed CMOS camera is used to measure the trap stiffness of holographic optical tweezers. In order to improve the accuracy of measurement, a piezoelectric platform is driven by multi-frequency sine-wave voltages to produce different fluid friction on a microsphere trapped by holographic optical tweezers. Experiments demonstrate that the method can effectively obtain the trap stiffness; with the increase of the laser output power, the trap stiffness rises linearly.