Finite element modelling of the expanson of small tubular parts by internal pressure

A stent is a device that is used to support arterial walls to alleviate the blockage of arteries by plaque. The slotted tube stent is one of the most common stent designs being widely used in many patients today. The amount of stent implantations is growing each year and for this it is becoming increasingly important in interventional cardiology. One of the reasons is that the use of stents has proved more effective in the therapy of coronary stenosis. However, it is evidenced that the success of the stent implantation is limited by re-stenosis, which is discussed almost entirely in terms of medical and biological reasons. This work is concerned with investigating the deformation mechanism with variable conditions during slotted tube expansion processes using numerical simulation. The simulations were run and analysed using commercial finite element software. A nonlinear explicit solution method was used in each case. The processes chosen for simulation were: slotted tube expansion without balloon catheter, slotted tube expansion with balloon catheter, scaling the stent size, stent production defect and slotted tube expansion with the presence of artery and plaque. A number of process parameters were varied for balloon catheter (i.e. balloon length, thickness and friction factor) and the subsequent effects on the process were identified. Some trial experimental tests were carried out to verify the finite element results from the computer simulations. From the results obtained it was concluded that higher rate of pressure increase results in higher stresses in stent for similar levels of expansion. Deployment of higher magnitude pressure might increase the expansion in radial direction but it does not necessarily increase the uniformity of the slotted tube. Appropriate balloon length has to be chosen to obtain a uniform expansion. Friction could reduce the foreshortening of the stent. When scaling down the stent, displacement deceases proportionally for similar deployment pressure and stent geometry. It was found from the simulations that the tubular stent is not very sensitive to imperfections. Altering sent strut configuration and number has practical effects on the clinical use of vascular stents, as the magnitude of expansion will change. The deformation characteristic of the slotted tube during deployment is affected by the presence of artery and plaque

Detection of Bond Pad Discolorations at Outgoing Wafer Inspections

Deployment of an automatic visual inspection system in semiconductor industry has become increasingly popular than ever not only due to its relatively high value as a yield analysis tool of outgoing products but more importantly for the prevention of defect escapee. A lot of studies are done on the application of in-line defect scan but the application of outgoing wafer inspection at post-fab environment has been very limited and rarely found in literature. With rapid growth of automotive application in worldwide industry, the importance of quality of the wafer at die level has never been so critical. This paper provides a method for detection of bond pad discolorations at outgoing quality check especially in semiconductor industry. An effective method for detection of the bond pad discolorations was proposed. The advantages and disadvantages of the detection method are discussed. Factors that are affecting the performances of the detection method are also described and analyzed. © 2017 IEEE

Potential use of coconut husk-based magnetic sorbent for defoaming application

Absorption process is the most common method that is being applied to sweeten sour gas in the oil and gas industry. However, this process does have several consequences which will trigger the foam formation of foam that will reduce the mass transfer efficiency and absorption capacity as well as amine solutions carryover to the downstream processes. The removal of undesired contaminants in activated methyldiethanolamine (MDEA) was conducted by utilizing magnetic activated carbon (MAC). In this work, MAC was synthesized from coconut husk through chemical activation and co-precipitation methods. The performance of this material as an adsorbent was evaluated based on the foaming behaviour of activated MDEA solvent after being contacted with MAC at different duration and varying amounts. Nitrogen gas was introduced into the solvent through a gas diffuser to create foam. Based on the results, the foam volume generated by activated MDEA solvent was identified to decrease with the increase in both MAC contact time and amount. The highest removal efficiency by MAC was identified to be at 1 h contact time between MAC and activated MDEA solvent where the foam breaking time was reduced to 10–30 min. Meanwhile, the addition of 50 % MAC into the solvent was able to further decrease the foam breaking time to 5–10 min. The characteristics of the prepared MAC were evaluated through various instrumental analyses. This study shows that the MAC synthesized from coconut husk has a good potential as an adsorbent in removing the contaminants in activated MDEA solvent to reduce foam formation

Development of young sago palm environmental monitoring system with wireless sensor networks

Environmental monitoring plays a significant role in the agriculture field as it manages the critical factors required for sustainable growth of plants, and thus enhancing the quality and productivity of the crops. In this paper, the development of a wireless sensor network (WSN) monitoring system for young sago palms in mist chambers is presented. The effect of the functional system with respect to the environmental factors monitored is also discussed. The system was set up to monitor three environmental factors i.e., temperature, relative humidity, and light intensity. Instantaneous readings of the monitored parameters were made possible through a wireless network and a web portal connection. The system recorded the environmental reading at every 15-min interval and transmitted the data from node to base using the Zigbee network. The data was then stored in an online cloud platform through the general radio packet service (GPRS) gateway. Linear actuators were also installed to control the mist chamber doors opening for natural ventilation and they were automatically triggered by the threshold temperature. Besides, a smart alert system was added to the system prompting for actions via short messaging services (SMS) when triggered. The developed system achieved a reliable data transmission with a low packet loss rate (PLR) of 2.3%. The use of the GPRS gateway also enabled the system to operate at a lower cost as the mobile data consumption was low (10 MB per month). In conclusion, a WSN system for mist chambers in a sago palm greenhouse was successfully developed to real-time monitor the plant growing environment through data acquisition, data transmission and data visualisation. The developed WSN system had laid a foundation for smart farming. For future applications, the system could be further modified and developed for precision agriculture

Adsorption Equilibrium for Heavy Metal Divalent Ions (Cu2+, Zn2+, and Cd2+) into Zirconium-Based Ferromagnetic Sorbent

Zirconium-based ferromagnetic sorbent was fabricated by coprecipitation of Fe2+/Fe3+ salts in a zirconium solution and explored as a potential sorbent for removing the Cu2+, Zn2+, and Cd2+ from aqueous solution. The sorbent could easily be separated from aqueous solution under the influence of external magnetic field due to the ferromagnetism property. A trimodal distribution was obtained for the sorbent with average particle size of 22.7

Investigation of human arm musculoskeletal model using aluminium pole in palm oil harvesting process

Palm oil industry is one of the important sectors in Malaysia. The growth and development in this industry shows that Malaysia is one of the largest manufactures of palm oil in the world. However this industry does causing a lot of issues in Work-related Musculoskeletal Disorders (WMSDs) especially in Harvesting Process. In addition, some of the palm oil workers in Malaysia do not take serious consideration in ergonomics awareness for their safety and health. Most of the workers are still using manual tools such as aluminium pole which has a high potential to expose to the ergonomics risk factors. Upon that situation, these studies are focusing to identify the force reaction of arm muscle and the muscle activity throughout the movement of the worker using aluminium pole in palm oil harvesting process. Inverse Dynamic Analysis is used to investigate the modelled simulation

Person Verification Based on Multimodal Biometric Recognition

Nowadays, person recognition has received significant attention due to broad applications in the security system. However, most person recognition systems are implemented based on unimodal biometrics such as face recognition or voice recognition. Biometric systems that adopted unimodal have limitations, mainly when the data contains outliers and corrupted datasets. Multimodal biometric systems grab researchers’ consideration due to their superiority, such as better security than the unimodal biometric system and outstanding recognition efficiency. Therefore, the multimodal biometric system based on face and fingerprint recognition is developed in this paper. First, the multimodal biometric person recognition system is developed based on Convolutional Neural Network (CNN) and ORB (Oriented FAST and Rotated BRIEF) algorithm. Next, two features are fused by using match score level fusion based on Weighted Sum-Rule. The verification process is matched if the fusion score is greater than the pre-set threshold t. The algorithm is extensively evaluated on UCI Machine Learning Repository Database datasets, including one real dataset with state-of-the-art approaches. The proposed method achieves a promising result in the person recognition system

QUANTIFICATION ASSESSMENT OF MUNICIPAL SOLID WASTE AS AN EVALUATION APROPOS OF SUSTAINABLE WASTE MANAGEMENT IN KUCHING

The quantification and characterisation of municipal solid waste are indispensables for waste management forethought. This study quantified the municipal solid wastes from three principal council areas in Kuching, the capital city of Sarawak, Malaysia which are the Kuching South City Council, Kuching North City Hall and Padawan Municipal Council to evaluate and analyse the contemporary waste trend and differentiate between the waste streams. The municipal solid waste samples are amassed directly from the source location and categorised according to the socio-economic level of the sampling location sites. This study discovered that there is no significant difference in the waste composition trend generated by the residents in different residential areas. The composition of the solid wastes was found to vary in different socio-economic categories. Organic waste is found to be the highest waste component in all socio-economic groups. The top three municipal waste compositions from the residential areas are organic wastes (61.58% w/w), plastics (12.06% w/w) and nappies/sanitary napkins (11.67% w/w), which ranged from 44.57% to 72.08%. This study provides a recent waste trend database with a detailed analysis of the differences between the waste streams for sustainable waste management in Kuching