Lattice Boltzmann simulation of plume behavior from an eccentric annulus cylinder

In this paper, a double-population thermal lattice Boltzmann was applied to solve two dimensional, incompressible, thermal fluid flow problems. The simplest lattice BGK D2Q4 model was applied to determine the temperature field while D2Q9 for the density and velocity fields. The simulation of natural convection from a concentrically and eccentrically placed inner heated cylinder inside cold outer cylinder with Prandtl number 0.71 and Rayleigh number 5 x was observed that the combination of D2Q4 and D2Q9 10 5 were carried out and discussed quantitatively. It was able to reproduce the effect of buoyancy force in the system. We also found that the flow pattern including the boundary layers and vortices with heat transfer mechanisms is significantly influenced by the position of heated cylinder in the enclosure and excellent comparisons with previous studies

Development of finite different lattice boltzmann scheme for the computation of natural convection heat transfer

This thesis presents a numerical study of flow behavior from a heated concentric annulus cylinder at various Rayleigh number Ra, Prandtl number Pr and aspect ratio of the outer and inner cylinders. The finite different lattice Boltzmann method (FDLBM) numerical scheme is developed to improve the computational efficiency and numerical stability of the conventional method. The proposed FDLBM applied UTOPIA approach (third order accuracy in space) to study the temperature distribution and the vortex formation in the annulus. D2Q9 velocity model was coupled with D2Q4 velocity model to represent the density and internal energy distribution function respectively. The comparison of the flow pattern and temperature distribution for every case via streamline, vortices and temperature distribution contour with published paper in literature were carried out for the validation purposes. Current investigation concluded that the UTOPIA FDLBM is an efficient approach for the current problem in hand and good agreement with the benchmark solutio

Hand-arm vibration disorder among grass-cutter workers in Malaysia

Prolonged exposure to hand-transmitted vibration from grass-cutting machines has been associated with increasing occurrences of symptoms and signs of occupational diseases related to hand-arm vibration syndrome (HAVS). Methods. A cross-sectional study was carried out using an adopted HAVS questionnaire on hand-arm vibration exposure and symptoms distributed to 168 male workers from the grass and turf maintenance industry who use hand-held grass-cutting machines as part of their work. The prevalence ratio and symptom correlation to HAVS between high and low–moderate exposure risk groups were evaluated. Results. There were positive HAVS symptoms relationships between the low–moderate exposure group and the high exposure group among hand-held grass-cutting workers. The prevalence ratio was considered high because there were indicators that fingers turned white and felt numb, 3.63, 95% CI [1.41, 9.39] and 4.24, 95% CI [2.18, 8.27], respectively. Less than 14.3% of workers stated that they were aware of the occupational hand-arm vibration, and it seemed to be related to the finger blanching and numbness. Conclusion. The results suggest that HAVS is under-diagnosed in Malaysia, especially in the agricultural sectors. More information related to safety and health awareness programmes for HAVS exposure is required among hand-held grass-cutting workers

Dynamorphic legumes

Basically, my approach is rooted from natural form of composition and improvisation. To compose in the medium of the artistic presentation, the works make temporality interactive. It creates a visual display which evolves dynamically over time, instead of a single static frame, or a preset filmic sequence. The works invoke cross-rhythm, the systematic interplay of contrasting rhythmic motions within a single metric scheme. It brings the operation of an artistic form to the context of browsing the scientific world of presentation. The works were presented in adaptive functional aspects that interconnected to the viewer into visual intuitive form which creates patterns of attention that organize our faculties of perception

Surface Erosion of Carbon Steel 1045 During Waterjet Peening

The present study investigates the effect of waterjet treatment on the surface characteristics of the carbon steel 1045. The effect of waterjet treatment parameters namely number of jet passes and pressure was investigated. An increase in the number of jet passes as well as pressure leads to a higher roughness and more erosion of the surface. The damage features consist of various fracture mechanism modes occurred at the initial and evolved damage stage. The ferrite phase experienced more damage than the pearlite phase. However, the damage was more concentrated along the grain boundaries. The shearing force from the jet lateral flow raised the circumferential rim and created lateral cracks and sub-tunnels which might eventually be removed in the subsequent jet passes. The hardness of the treated specimens increased with an increase in the number of jet passes and pressure

Secure multicast group communication scheme in wireless IPv6 networks

Key management is one of the challenging issues in group communications. It is generally used to secure multicast data transmission as well as preventing potential eavesdropping by malicious attackers. Group security key should be maintained for data encryption, while group key update and dissemination processes are required when a new user joins or leaves the group, which eventually lead to high communication and computation cost. Since eavesdrop activities can be initiated by capturing the disseminated keys, higher communication and computation cost due to frequent updates also increase the possibility of attack of multicast transmission. In this paper, a key management scheme for IPv6 networks is proposed to reduce communication and computation cost and therefore, fewer security risks. The obtained results from test-bed implementation show the efficiency of proposed scheme in terms of communication and computation cost, number of updated paths and security index due to key updating, while at the same time achieving both forward and backward secrecy

Optimization of EDM Injection Flushing Type Control Parameters Using Grey Relational Analysis on AISI 304 Stainless Steel Workpiece

This paper deals with optimization of Electrical Discharge Machining (EDM) Injection flushing type control parameters on multi-performance optimization characteristics instead of single performance optimization using Grey Relational Analysis (GRA) Method. The experimental control parameters were being optimized according to their various machining characteristics namely material removal rate (MRR), electrode wear ratio (EWR) and surface roughness (SR) using copper as the tool and AISI 304 stainless steel as the workpiece. This parameters optimization was based on Taguchi’s orthogonal array (OA) combined with GRA. A grey relational grade (GRG) calculated based on GRA was used to optimize the EDM process with multiple performance characteristics and Taguchi’s L18 OA was used to plan the experiments. The machining parameters selected are polarity, pulse on duration, discharge current, discharge voltage, machining depth, machining diameter and dielectric liquid pressure. Results shown that machining performance was improved effectively using this approach. The predicted responses at optimum parameter levels are in good agreement with the results of confirmation experiments conducted for verification tests

Active involvement of students in co-curriculum (sports) versus generic skills

The active involvement of students in sports activities is viewed from different levels of achievement beginning with the national representation of the residential colleges, faculties, and universities in prestigious sporting events at international levels. The skills that are developed through extra-curricular activities are generic skills. The involvement of students in co-curricular activities can help to shape their generic skills, thus leading to self-promotion in the workplace. Therefore, the purpose of this research was to examine the enhancement of generic skills among engineering and technical students of UTHM who are actively involved in co-curricular activities (sports). This study will focus on identifying the factors of involvement, the level of application among students, and the perceptions of the students through their active involvement in extra-curricular activities (sports). A survey was conducted using a quantitative approach. A general questionnaire, which was designed to fulfil the objectives and to answer the research questions for this study, was distributed to 213 engineering and technical student athletes of UTHM who are actively involved in co-curricular activities (sports). It was found that the engineering and technical student athletes of UTHM agreed that their active involvement in extra-curricular activities (sports) was due to interpersonal, intrapersonal and structural factors. The results showed that out of seven generic skills, three constructs of generic skills, namely communication, teamwork and management, demonstrate a high level of application through active involvement in extra-curricular activities (sports). These findings may also help the university to focus on the development of generic skills in engineering and technical students through co-curricular activities (sports) in addition to producing athletes who are able to create a name for the university at national or international level

Narrowband elliptic bandpass filter using dual-mode microstrip square loop resonator for WiMax application

In this paper, a narrowband bandpass filter using dual-mode microstrip square loop resonator is proposed. This structure has a 5.1% fractional bandwidth at 2.3GHz. By using some simple techniques, the optimum results will be achieved. The dual-mode resonator will be produced by adding a square patch inside the loop resonator. The simulation and measurement results are also presented. The filter is fabricated on RT/Duroid 6010 substrate having a relative dielectric constant of 10.2 and 0.635 mm thickness. The final dimension is measured at 19.65 mm 19.65 mm. The minimum measured insertion loss is 1.68 dB and return loss obtained is better than -20 dB, where experimental results and simulated values are in good agreement