Advanced Materials Research Vol. 701

Abstract: Flowability indicates the degree of ease of flow. For dynamic (or aerated) flowability, Hausner Ratio (HR) and Angle of Repose (AOR) have been established as a strong indicator for flowability. In this work the influence of particle size and relative humidity (RH) on the flowability of silica gel and ballotini powders were investigated using a non-aerated method. The non-aerated method is a cohesion index (CI) measurement based on a Stable Micro Systems TA.XT PLUS texture analyzer (SMS). The results of the indicator measured confirmed the general expectation that the fine powders are cohesive and the coarse powders are free-flowing at low RH. An interesting trend was observed on the humidity effect study where in low humidity, the powder maintained to be more free-flowing than the powder after the drying process up to a certain limit of RH. However at humidity above this limit, the flowability indicator of the powder is decreasing below than the measureed dry powder flowability. Moreover the apparatus has proven equipment ability to predict even small changes in cohesion value and that using non-aerated methods is greatly important to evaluate the flowability and the powder behavior under different conditions (dynamic and static). It is observed that there are numerous factors related with powder flowability.

Abstract: Poly (caprolactone) (PCL) was selected as the substance for producing the ultrafine fiber using the eletrospinning process. The effect of the solution concentration on fiber size was studied to determine the condition for preparing PCL fiber mats with desired size range. PCL fiber mats with three different fiber sizes, i.e. 440 nm, 960 nm and 4.6 μm, were prepare and used to evaluate effect of fiber size on cell adhesion and proliferation using L929 as a model cell. The results showed that while fiber size has no effect on initial cell attachment, the mat with medium and large fibers showed higher cell proliferation than the mat with small fiber. Fiber size also played role in prohibiting or accommodating cellular distribution or penetration into the under layer of electrospun fiber mat.

Abstract: Results from Finite Element (FE) study on the response of composite cylinder shells with cutouts and subjected to internal pressure and axial compression are presented. The objective of the study is to improving the buckling load by applying the internal pressure whilst the compression load is applied. The effect of localized stress concentration distributed around the cutout region also being examined. The numerical results are obtained using ABAQUS finite element code software package. The composite cylinder shells were tested in two conditions which are a combination of axial compression load with internal pressure and a single axial compression load. The effects of varying internal pressure and cutout size on the pre-buckling, buckling, and post-buckling responses of the shell are demonstrated. Reasonable results comparison was obtained by reviewing previous literature. Results indicated that the load distribution and displacement of the cutout significantly influence the structural response of the shell. The results also indicate that the stress distributions can be affected by the size of the cutout under axial compression load.

Abstract: The establishment of high-performance materials made from natural resources is increasing worldwide. Recently, there are exceptional accomplishments in green technology in materials science field via the development on natural fibers utilization due to sustainability and environment issues. One of the natural fibers that getting more attention is pineapple leaf fibers (PALF). Since PALF consist of high cellulose contents and mechanically sounds, it has seen a tremendous increase in use as reinforcement in polymer composites. This paper presented a comprehensive review of literature on the utilization of PALF nowadays. The PALF characteristics in terms of chemical composition and properties including mechanical properties, as well as thermal properties will be reviewed and summarized in this paper. Several studies have shown that the common modification methods used are silane and alkaline treatment. Finally, this review will conclude all the current developments and trends of PALF utilization as well as key issues that need to be considered for future works.

Abstract: Myogram on-and-off controller is important for improving or assisting the elderly people. One of the most important aspects of the controller development is to determine the on and off time with respect to the body movement. In this project, high accuracy signal filtering, high gain amplifier, signal converter, microcontroller and electrodes are used for circuit simulation and development to obtain muscle signal (Electromyogram). Precision rectifier is used to solve the ordinary semiconductor problem to avoid signal block. To ensurethe user-friendliness in the development of this device, non-invasive electrodes are used in this project instead of invasive electrodes.

Abstract: Sand production is a serious problem during the exploitation of oil wells, and people put forward the concept of limited sand to alleviate this problem. Oil production with limited sanding is an efficient mod of production. In order to complete limited sand exploitation, improve the productivity of oil wells, a real-time sand monitoring system is needed to monitor the status of wells production. Besides acoustic sand monitoring and erosion-based sand monitoring, a vibration-based sand monitoring system with two installing styles is proposed recently. The paper points out the relationships between sand monitoring signals collected under intrusive and non-intrusive installing styles and sanding parameters, which lays a good foundation for further study and actual sand monitoring in oil field.