This edition first published 2017@)2017 John \Xlile)' & Sons Ltd 1\11rights reserved. No part of ... more This edition first published 2017@)2017 John \Xlile)' & Sons Ltd 1\11rights reserved. No part of this publication rna)' be reproduced, stored in a retrieval system, or transmitted. in any form or by an) mum. electronic. mechanical. photocopying. recording or otherwise, except as permitted by law.Advice On how to obtain permision to reuse material (rom this title is available at ht 11>:llwww,wiley,cont/go/pennissions, The right of C, Anandharamakrishnan to be identified as the author of the editorial material in this work has been asserted in accordance with law.
This paper presents a comparison between the two-and three-dimensional particle image velocimetry... more This paper presents a comparison between the two-and three-dimensional particle image velocimetry (PIV) measurement of air flow over a scaled-down model of Bukit Gemok in Telok Kalong industrial area (TKIA). The 2D PIV was performed using a single camera setup, while the 3D PIV was performed stereoscopically using a two-camera setup. The surface terrain map was obtained from google earth, which was then converted to a CAD format and the scaled down model was made using a 3D printer. The PIV measurement was performed in a wind tunnel. The results on the axial and streamwise velocity profile shows that, there are difference in the measured velocities obtained from the 2D and 3D PIV. The difference is less pronounced for the streamwise velocity but a greater difference was observed for the mean axial velocity (~30%). In addition, the 3D PIV method captures the wake flow and vortices much better than that of 2D PIV. The data obtained from this work may be useful for Computational Fluid Dynamics validation of flow over TKIA.
Grain storage and milling plant, Lumut, Perak March 17, 2008 Grain dust explosion 4 Dead, 2 injur... more Grain storage and milling plant, Lumut, Perak March 17, 2008 Grain dust explosion 4 Dead, 2 injured 34 Incidents in Malaysia Motorcycle rim manufacturing factory, Pulau Pinang March, 2010 Aluminum dust explosion 8 injured and cause damaged the building, manufacturing plant, dust collector system and broke the windows of nearby factories.
IOP Conference Series: Materials Science and Engineering, 2020
This paper presents the prediction of hypothetical chlorine leak dispersion around Gebeng industr... more This paper presents the prediction of hypothetical chlorine leak dispersion around Gebeng industrial area using Areal Location of Hazardous Atmosphere (ALOHA) software. The effect of the different wind speed and direction to chlorine dispersion in the meteorological microscale area was investigated. The wind speed ranging from 1.32 to 10.7 m/s obtained from a local weather station was considered. Heavy gas dispersion model was used to determine the concentration of chlorine plume within the area of concern. The leakage rate was set to correspond to a leakage from the chlorine tank at 792 kg/h. The result showed that the residential areas R1 and R2 are affected by the plume dispersed by southwest and northern winds, respectively. A greater hazard area was found when the wind speed is below 2.3 m/s. Meanwhile, the hazard zone reduced to nearly half when the wind speed is above 5.4 m/s. The appropriate evacuation routes were developed to reduce risk of exposure to toxic gas. Finding fr...
This paper presents a scale-adaptive simulation (SAS) of a partial combustion lance (PCL) aiming ... more This paper presents a scale-adaptive simulation (SAS) of a partial combustion lance (PCL) aiming to evaluate the influence of thermal insulation on the performance of syngas combustion. Standard kε (SKE) and Reynolds stress model (RSM) were used for comparison. The combustion reaction was modelled using eddy dissipation model (EDM), non-premixed and partially premixed flame models. Discrete ordinates (DO) and spherical harmonics (P-1) were used to calculate the radiative heat transfer. The finding suggests that SAS provides a better prediction for reactive turbulent flow. In the present work, simulation of syngas combustion using non-premixed flame with a DO approach showed the best agreement with experimental data by about 5.3%. Installation of an insulator increases the peak outlet temperature by about 20.4%.
In this study, the dust distribution in a silo during axial filling was modelled using a commerci... more In this study, the dust distribution in a silo during axial filling was modelled using a commercial computational fluid dynamics (CFD) code. The work focused on the dust concentration distribution in the silo, for evaluating the likelihood of a dust explosion in the silo. The simulation was conducted using a combination of renormalized (RNG) k-epsilon and discrete phase models, with standard pressure interpolation and a second order upwind scheme. The predicted dust concentration distribution showed a good agreement with experimental data adopted from the literature. It was found that the dust concentration distribution was influenced by mean velocity and turbulence flow. The simulation results suggest that the cornstarch concentration inside the silo was always above the lower explosion limit (LEL), hence requiring a mitigating action or a control system to reduce the explosion risk.
This paper presents a computational fluid dynamics (CFD) study of gas-solid turbulence flow in a ... more This paper presents a computational fluid dynamics (CFD) study of gas-solid turbulence flow in a silo. The simulations were performed using three different turbulent models namely, standard k-ε (SKE), RNG k-ε (RNG) and Realizable k-ε (RKE). The gravitational force, Saffman lift force and two-way coupling effect were employed. The influence of grid size, discretization, modeling strategies and solver were examined. An Eulerian-Lagrangian approach was used to model the particle flow using Disperse Phase Model (DPM). The predicted gas-solid flow patterns inside the silo chamber were found to be in good agreement to the experimental data adopted from literature. Good predictions were achieved using RNG k-ε with discrepancy around 4%.
Open Journal of Inorganic Non-metallic Materials, 2014
during silo filling operation is important for safety measures. Thus, information on particles-ai... more during silo filling operation is important for safety measures. Thus, information on particles-air flow field is required to assess the likelihood of the hazard. Flow field visualization via experimental investigation associated with difficulties and risks. Hence, in the present study, a modeling formulation using commercial computational fluid dynamics (CFD) code, FLUENT software was employed to predict an insight of flow field distribution, in terms of mean and root mean square (RMS) velocities vectors in cylindrical silo during axial filling. According to the simulation results, predicted flow field has a great influence to the silo height and distance to the silo wall due to gravitational force and movement of fugitive dust and re-circulation of air. The results showed that the predicted data were in very good agreement with experimental data obtained from the literature. The maximum error was around 10%. The study has gone some way towards enhancing our understanding of the particles-air behavior inside industrial equipments during filling operation.
A detached eddy simulation (DES) and a k-ε-based Reynolds-averaged Navier-Stokes (RANS) calculati... more A detached eddy simulation (DES) and a k-ε-based Reynolds-averaged Navier-Stokes (RANS) calculation on the co-current spray drying chamber is presented. The DES used here is based on the Spalart-Allmaras (SA) turbulence model, whereas the standard k-ε (SKE) was considered here for comparison purposes. Predictions of the mean axial velocity, temperature and humidity profile have been evaluated and compared with experimental measurements. The effects of the turbulence model on the predictions of the mean axial velocity, temperature and the humidity profile are most noticeable in the (highly anisotropic) spraying region. The findings suggest that DES provide a more accurate prediction (with error less than 5%) of the flow field in a spray drying chamber compared with RANS-based k-ε models. The DES simulation also confirmed the presence of anisotropic turbulent flow in the spray dryer from the analysis of the velocity component fluctuations and turbulent structure as illustrated by the Q-criterion.
A computational fluid dynamics (CFD) study of a partial combustion lance (PCL) was performed usin... more A computational fluid dynamics (CFD) study of a partial combustion lance (PCL) was performed using a hybrid scale adaptive simulation (SAS) in this work. In addition, the unsteady Reynolds-averaged NavierStokes (URANS) simulations using the standard k-e (SKE), realizable k-e (RKE) and renormalized (RNG) k-e were performed for comparison purpose. Combustion was modelled using the species transport model, whereas the heat transfer was calculated using a combined convection-radiation boundary condition. Suitability of various gradient methods (i.e., Green-Gauss node-based, Green-Gauss cell-based and least squares cell-based) to discretize the convection and diffusion terms in the governing equations were assessed by comparing the CFD prediction with experimentally measured temperature. It was found that SAS provided a better prediction of the PCL temperature with about 5.1 % of error from the experimental data. The Green-Gauss node-based method showed a better agreement compared to the...
Fins are used to reduce heat from electronic devices. There are two types of cooling system to di... more Fins are used to reduce heat from electronic devices. There are two types of cooling system to dissipate heat from devices through fins. One of them is liquid-cooling and the other is air-cooling. In this research heat transfer through fins are investigated for one and two dimensional heat conduction problems. Finite element method (FEM) discretization for equal and non-equal spacing meshes are computed here to obtain numerical solutions for the above problems and the results are compared with the exact results. It is found that numerical results agree very well with exact results. But it is also found that non-equal spacing mesh distribution produces more accurate results than equal spacing mesh.
This work presents an optimization study of polyphenol extraction from L. pumila with aid of soni... more This work presents an optimization study of polyphenol extraction from L. pumila with aid of sonication. The polyphenol content was evaluated using Singleton’s method and aluminium chloride colorimetric assay. The two level factorial design [2LF] was used to screen the significance of the extraction parameters. The results proposed that the polyphenols extraction are mainly affected by the total solid ratio [TSR] and residence time. The highest flavonoid content of 31.79 mg QE/ g DW and phenolic content of 19.65 mg GA/g DW was obtained from 80% and 10% aqueous ethanol [EtOH], respectively via 2LF design. Three most important parameters [TSR, residence time and amplitude] were then further optimized thru central composite design. The highest simultaneous flavonoid [21.77 mg QE/ g DW] and phenolic [21.86 mg GA/g DW] extraction yield were attained from the probe sonicator extraction with desirability of 0.998 at 10% aqueous EtOH with TSR 0.01, residence time of 13 min and amplitude of ...
This paper presents the structural behaviour of reinforced concrete (RC) beams with and without o... more This paper presents the structural behaviour of reinforced concrete (RC) beams with and without openings strengthened externally with bamboo fiber reinforced composite (BFRC) plates in shear and flexure, respectively. Mechanical properties include tensile and flexural strength of epoxy, polyester and vinyl-ester based BFRC plates with 0%, 10%, 20%, 30% and 40% fiber volume fractions were evaluated. A total of fourteen beams were cast to evaluate the structural behaviour of RC beams strengthened with BFRC plates. All the beams were tested to failure under four-point bending. The results presented were in terms of load–deflection behaviour, failure mode and crack pattern. A comparison was also made between the performance of epoxy, polyester and vinyl-ester based BFRC plates in shear strengthening of RC beams with openings. Results revealed that the presence of openings in the shear zone reduced the original beam capacity of the control beam to about 52–55%. Shear strengthening of RC ...
3RD INTERNATIONAL CONFERENCE ON CHEMISTRY, CHEMICAL PROCESS AND ENGINEERING (IC3PE)
Tea dust is classified as combustible agricultural dust. Manufacturing processes of tea frequentl... more Tea dust is classified as combustible agricultural dust. Manufacturing processes of tea frequently involve a falling stream of tea powder and induced smaller dust to the surrounding, forming a dust cloud. Under certain circumstances, there are potential for rapid combustion and serious explosion to occur. Herein, experimental research results are reported in this study, focusing in particular on the flow field of tea dust during free-falling. This investigation shows that the axial velocity is found to increase significantly with increasing conveying speed, however the RMS turbulent velocity shows slight fluctuations from each other. Both velocities are found to increase linearly with increasing drop height, and similar flow field patterns are found for a all conveying speeds. Also, high flow field is observed towards the core of the particle-driven plume and decreases to the wall. The results presented here may facilitate fundamental knowledge on dust cloud formation to enhance awareness for dust control and prevention in agricultural industries.
This paper describes an experimental set up to examine the relationship between powder properties... more This paper describes an experimental set up to examine the relationship between powder properties on powder flow pattern during filling operation. For this purpose, the free fall velocities of four types of agricultural dusts (i.e. castor sugar, oat, semolina and tea powder) in a rectangular enclosure were captured using a Particle Image Velocimetry (PIV). The result reveals that oat powder portrayed greater cloud dispersion due to its flaky shape and a lower bulk density. The characteristics of oat powder allowed more air to be dragged into the particle stream and forced the particle to be dispersed and suspended in air due to drag force and terminal velocity. The result presented here may facilitate improvements in dust control and measures in powder industries.
A synergistic effect of the activated limestone-based catalyst (LBC) and microwave irradiation on... more A synergistic effect of the activated limestone-based catalyst (LBC) and microwave irradiation on the transesterification of waste cooking oil (WCO) was screened using a two-level factorial design and response surface methodology. The catalyst was prepared using a wet-impregnation method and was characterised for its surface element, surface morphology, surface area and porosity. The reaction was performed in a purpose-built continuous microwave assisted reactor (CMAR), while the conversion and yield of biodiesel were measured using a gas chromatography. The results showed that the catalyst loading, methanol to oil molar ratio and the reaction time significantly affect the WCO conversion. The optimum conversion of oil to biodiesel up to 96.65% was achieved at catalyst loading of 5.47 wt%, methanol to oil molar ratio of 12.21:1 and the reaction time of 55.26 min. The application of CMAR in this work reduced the transesterification time by about 77% compared to the reaction time needed for a conventional reactor. The biodiesel produced in this work met the specification of American Society for Testing and Materials (ASTM D6751). Engine test results shows the biodiesel has a lower NOx and particulate matters emissions compared to petrodiesel.
Abstract The effect of size reduction and extraction methods on the gallic acid (GA) extraction y... more Abstract The effect of size reduction and extraction methods on the gallic acid (GA) extraction yield from Labisia pumila leaf is presented. The GA extraction from a dried powdered L. pumila leaves with particle size distribution ranging from 66.66 to 1055.18 μm was performed using 10% aqueous ethanol. Three different extraction methods such as microwave assisted extraction (MAE), ultrasonic assisted extraction (UAE) and maceration extraction (ME) were used for comparison. Scanning electron microscopy (SEM) was used for microstructures analysis of the untreated and treated plant. The SEM analysis showed that the MAE led to a stronger disruption on the epidermal cells and glandular trichomes of L. pumila compared to other extraction methods. The highest GA extraction yield at 0.32 mg/g DW was obtained using MAE method, followed by UAE (0.11 mg/g DW) and ME (0.08 mg/g DW). It was found that the particle size about 252.15 μm yielded a higher extraction yield of GA at 0.083 mg/g DW compared to the other particle size. The finding in this work may serve as a useful guide to obtain highest GA extraction yield from L. pumila.
This edition first published 2017@)2017 John \Xlile)' & Sons Ltd 1\11rights reserved. No part of ... more This edition first published 2017@)2017 John \Xlile)' & Sons Ltd 1\11rights reserved. No part of this publication rna)' be reproduced, stored in a retrieval system, or transmitted. in any form or by an) mum. electronic. mechanical. photocopying. recording or otherwise, except as permitted by law.Advice On how to obtain permision to reuse material (rom this title is available at ht 11>:llwww,wiley,cont/go/pennissions, The right of C, Anandharamakrishnan to be identified as the author of the editorial material in this work has been asserted in accordance with law.
This paper presents a comparison between the two-and three-dimensional particle image velocimetry... more This paper presents a comparison between the two-and three-dimensional particle image velocimetry (PIV) measurement of air flow over a scaled-down model of Bukit Gemok in Telok Kalong industrial area (TKIA). The 2D PIV was performed using a single camera setup, while the 3D PIV was performed stereoscopically using a two-camera setup. The surface terrain map was obtained from google earth, which was then converted to a CAD format and the scaled down model was made using a 3D printer. The PIV measurement was performed in a wind tunnel. The results on the axial and streamwise velocity profile shows that, there are difference in the measured velocities obtained from the 2D and 3D PIV. The difference is less pronounced for the streamwise velocity but a greater difference was observed for the mean axial velocity (~30%). In addition, the 3D PIV method captures the wake flow and vortices much better than that of 2D PIV. The data obtained from this work may be useful for Computational Fluid Dynamics validation of flow over TKIA.
Grain storage and milling plant, Lumut, Perak March 17, 2008 Grain dust explosion 4 Dead, 2 injur... more Grain storage and milling plant, Lumut, Perak March 17, 2008 Grain dust explosion 4 Dead, 2 injured 34 Incidents in Malaysia Motorcycle rim manufacturing factory, Pulau Pinang March, 2010 Aluminum dust explosion 8 injured and cause damaged the building, manufacturing plant, dust collector system and broke the windows of nearby factories.
IOP Conference Series: Materials Science and Engineering, 2020
This paper presents the prediction of hypothetical chlorine leak dispersion around Gebeng industr... more This paper presents the prediction of hypothetical chlorine leak dispersion around Gebeng industrial area using Areal Location of Hazardous Atmosphere (ALOHA) software. The effect of the different wind speed and direction to chlorine dispersion in the meteorological microscale area was investigated. The wind speed ranging from 1.32 to 10.7 m/s obtained from a local weather station was considered. Heavy gas dispersion model was used to determine the concentration of chlorine plume within the area of concern. The leakage rate was set to correspond to a leakage from the chlorine tank at 792 kg/h. The result showed that the residential areas R1 and R2 are affected by the plume dispersed by southwest and northern winds, respectively. A greater hazard area was found when the wind speed is below 2.3 m/s. Meanwhile, the hazard zone reduced to nearly half when the wind speed is above 5.4 m/s. The appropriate evacuation routes were developed to reduce risk of exposure to toxic gas. Finding fr...
This paper presents a scale-adaptive simulation (SAS) of a partial combustion lance (PCL) aiming ... more This paper presents a scale-adaptive simulation (SAS) of a partial combustion lance (PCL) aiming to evaluate the influence of thermal insulation on the performance of syngas combustion. Standard kε (SKE) and Reynolds stress model (RSM) were used for comparison. The combustion reaction was modelled using eddy dissipation model (EDM), non-premixed and partially premixed flame models. Discrete ordinates (DO) and spherical harmonics (P-1) were used to calculate the radiative heat transfer. The finding suggests that SAS provides a better prediction for reactive turbulent flow. In the present work, simulation of syngas combustion using non-premixed flame with a DO approach showed the best agreement with experimental data by about 5.3%. Installation of an insulator increases the peak outlet temperature by about 20.4%.
In this study, the dust distribution in a silo during axial filling was modelled using a commerci... more In this study, the dust distribution in a silo during axial filling was modelled using a commercial computational fluid dynamics (CFD) code. The work focused on the dust concentration distribution in the silo, for evaluating the likelihood of a dust explosion in the silo. The simulation was conducted using a combination of renormalized (RNG) k-epsilon and discrete phase models, with standard pressure interpolation and a second order upwind scheme. The predicted dust concentration distribution showed a good agreement with experimental data adopted from the literature. It was found that the dust concentration distribution was influenced by mean velocity and turbulence flow. The simulation results suggest that the cornstarch concentration inside the silo was always above the lower explosion limit (LEL), hence requiring a mitigating action or a control system to reduce the explosion risk.
This paper presents a computational fluid dynamics (CFD) study of gas-solid turbulence flow in a ... more This paper presents a computational fluid dynamics (CFD) study of gas-solid turbulence flow in a silo. The simulations were performed using three different turbulent models namely, standard k-ε (SKE), RNG k-ε (RNG) and Realizable k-ε (RKE). The gravitational force, Saffman lift force and two-way coupling effect were employed. The influence of grid size, discretization, modeling strategies and solver were examined. An Eulerian-Lagrangian approach was used to model the particle flow using Disperse Phase Model (DPM). The predicted gas-solid flow patterns inside the silo chamber were found to be in good agreement to the experimental data adopted from literature. Good predictions were achieved using RNG k-ε with discrepancy around 4%.
Open Journal of Inorganic Non-metallic Materials, 2014
during silo filling operation is important for safety measures. Thus, information on particles-ai... more during silo filling operation is important for safety measures. Thus, information on particles-air flow field is required to assess the likelihood of the hazard. Flow field visualization via experimental investigation associated with difficulties and risks. Hence, in the present study, a modeling formulation using commercial computational fluid dynamics (CFD) code, FLUENT software was employed to predict an insight of flow field distribution, in terms of mean and root mean square (RMS) velocities vectors in cylindrical silo during axial filling. According to the simulation results, predicted flow field has a great influence to the silo height and distance to the silo wall due to gravitational force and movement of fugitive dust and re-circulation of air. The results showed that the predicted data were in very good agreement with experimental data obtained from the literature. The maximum error was around 10%. The study has gone some way towards enhancing our understanding of the particles-air behavior inside industrial equipments during filling operation.
A detached eddy simulation (DES) and a k-ε-based Reynolds-averaged Navier-Stokes (RANS) calculati... more A detached eddy simulation (DES) and a k-ε-based Reynolds-averaged Navier-Stokes (RANS) calculation on the co-current spray drying chamber is presented. The DES used here is based on the Spalart-Allmaras (SA) turbulence model, whereas the standard k-ε (SKE) was considered here for comparison purposes. Predictions of the mean axial velocity, temperature and humidity profile have been evaluated and compared with experimental measurements. The effects of the turbulence model on the predictions of the mean axial velocity, temperature and the humidity profile are most noticeable in the (highly anisotropic) spraying region. The findings suggest that DES provide a more accurate prediction (with error less than 5%) of the flow field in a spray drying chamber compared with RANS-based k-ε models. The DES simulation also confirmed the presence of anisotropic turbulent flow in the spray dryer from the analysis of the velocity component fluctuations and turbulent structure as illustrated by the Q-criterion.
A computational fluid dynamics (CFD) study of a partial combustion lance (PCL) was performed usin... more A computational fluid dynamics (CFD) study of a partial combustion lance (PCL) was performed using a hybrid scale adaptive simulation (SAS) in this work. In addition, the unsteady Reynolds-averaged NavierStokes (URANS) simulations using the standard k-e (SKE), realizable k-e (RKE) and renormalized (RNG) k-e were performed for comparison purpose. Combustion was modelled using the species transport model, whereas the heat transfer was calculated using a combined convection-radiation boundary condition. Suitability of various gradient methods (i.e., Green-Gauss node-based, Green-Gauss cell-based and least squares cell-based) to discretize the convection and diffusion terms in the governing equations were assessed by comparing the CFD prediction with experimentally measured temperature. It was found that SAS provided a better prediction of the PCL temperature with about 5.1 % of error from the experimental data. The Green-Gauss node-based method showed a better agreement compared to the...
Fins are used to reduce heat from electronic devices. There are two types of cooling system to di... more Fins are used to reduce heat from electronic devices. There are two types of cooling system to dissipate heat from devices through fins. One of them is liquid-cooling and the other is air-cooling. In this research heat transfer through fins are investigated for one and two dimensional heat conduction problems. Finite element method (FEM) discretization for equal and non-equal spacing meshes are computed here to obtain numerical solutions for the above problems and the results are compared with the exact results. It is found that numerical results agree very well with exact results. But it is also found that non-equal spacing mesh distribution produces more accurate results than equal spacing mesh.
This work presents an optimization study of polyphenol extraction from L. pumila with aid of soni... more This work presents an optimization study of polyphenol extraction from L. pumila with aid of sonication. The polyphenol content was evaluated using Singleton’s method and aluminium chloride colorimetric assay. The two level factorial design [2LF] was used to screen the significance of the extraction parameters. The results proposed that the polyphenols extraction are mainly affected by the total solid ratio [TSR] and residence time. The highest flavonoid content of 31.79 mg QE/ g DW and phenolic content of 19.65 mg GA/g DW was obtained from 80% and 10% aqueous ethanol [EtOH], respectively via 2LF design. Three most important parameters [TSR, residence time and amplitude] were then further optimized thru central composite design. The highest simultaneous flavonoid [21.77 mg QE/ g DW] and phenolic [21.86 mg GA/g DW] extraction yield were attained from the probe sonicator extraction with desirability of 0.998 at 10% aqueous EtOH with TSR 0.01, residence time of 13 min and amplitude of ...
This paper presents the structural behaviour of reinforced concrete (RC) beams with and without o... more This paper presents the structural behaviour of reinforced concrete (RC) beams with and without openings strengthened externally with bamboo fiber reinforced composite (BFRC) plates in shear and flexure, respectively. Mechanical properties include tensile and flexural strength of epoxy, polyester and vinyl-ester based BFRC plates with 0%, 10%, 20%, 30% and 40% fiber volume fractions were evaluated. A total of fourteen beams were cast to evaluate the structural behaviour of RC beams strengthened with BFRC plates. All the beams were tested to failure under four-point bending. The results presented were in terms of load–deflection behaviour, failure mode and crack pattern. A comparison was also made between the performance of epoxy, polyester and vinyl-ester based BFRC plates in shear strengthening of RC beams with openings. Results revealed that the presence of openings in the shear zone reduced the original beam capacity of the control beam to about 52–55%. Shear strengthening of RC ...
3RD INTERNATIONAL CONFERENCE ON CHEMISTRY, CHEMICAL PROCESS AND ENGINEERING (IC3PE)
Tea dust is classified as combustible agricultural dust. Manufacturing processes of tea frequentl... more Tea dust is classified as combustible agricultural dust. Manufacturing processes of tea frequently involve a falling stream of tea powder and induced smaller dust to the surrounding, forming a dust cloud. Under certain circumstances, there are potential for rapid combustion and serious explosion to occur. Herein, experimental research results are reported in this study, focusing in particular on the flow field of tea dust during free-falling. This investigation shows that the axial velocity is found to increase significantly with increasing conveying speed, however the RMS turbulent velocity shows slight fluctuations from each other. Both velocities are found to increase linearly with increasing drop height, and similar flow field patterns are found for a all conveying speeds. Also, high flow field is observed towards the core of the particle-driven plume and decreases to the wall. The results presented here may facilitate fundamental knowledge on dust cloud formation to enhance awareness for dust control and prevention in agricultural industries.
This paper describes an experimental set up to examine the relationship between powder properties... more This paper describes an experimental set up to examine the relationship between powder properties on powder flow pattern during filling operation. For this purpose, the free fall velocities of four types of agricultural dusts (i.e. castor sugar, oat, semolina and tea powder) in a rectangular enclosure were captured using a Particle Image Velocimetry (PIV). The result reveals that oat powder portrayed greater cloud dispersion due to its flaky shape and a lower bulk density. The characteristics of oat powder allowed more air to be dragged into the particle stream and forced the particle to be dispersed and suspended in air due to drag force and terminal velocity. The result presented here may facilitate improvements in dust control and measures in powder industries.
A synergistic effect of the activated limestone-based catalyst (LBC) and microwave irradiation on... more A synergistic effect of the activated limestone-based catalyst (LBC) and microwave irradiation on the transesterification of waste cooking oil (WCO) was screened using a two-level factorial design and response surface methodology. The catalyst was prepared using a wet-impregnation method and was characterised for its surface element, surface morphology, surface area and porosity. The reaction was performed in a purpose-built continuous microwave assisted reactor (CMAR), while the conversion and yield of biodiesel were measured using a gas chromatography. The results showed that the catalyst loading, methanol to oil molar ratio and the reaction time significantly affect the WCO conversion. The optimum conversion of oil to biodiesel up to 96.65% was achieved at catalyst loading of 5.47 wt%, methanol to oil molar ratio of 12.21:1 and the reaction time of 55.26 min. The application of CMAR in this work reduced the transesterification time by about 77% compared to the reaction time needed for a conventional reactor. The biodiesel produced in this work met the specification of American Society for Testing and Materials (ASTM D6751). Engine test results shows the biodiesel has a lower NOx and particulate matters emissions compared to petrodiesel.
Abstract The effect of size reduction and extraction methods on the gallic acid (GA) extraction y... more Abstract The effect of size reduction and extraction methods on the gallic acid (GA) extraction yield from Labisia pumila leaf is presented. The GA extraction from a dried powdered L. pumila leaves with particle size distribution ranging from 66.66 to 1055.18 μm was performed using 10% aqueous ethanol. Three different extraction methods such as microwave assisted extraction (MAE), ultrasonic assisted extraction (UAE) and maceration extraction (ME) were used for comparison. Scanning electron microscopy (SEM) was used for microstructures analysis of the untreated and treated plant. The SEM analysis showed that the MAE led to a stronger disruption on the epidermal cells and glandular trichomes of L. pumila compared to other extraction methods. The highest GA extraction yield at 0.32 mg/g DW was obtained using MAE method, followed by UAE (0.11 mg/g DW) and ME (0.08 mg/g DW). It was found that the particle size about 252.15 μm yielded a higher extraction yield of GA at 0.083 mg/g DW compared to the other particle size. The finding in this work may serve as a useful guide to obtain highest GA extraction yield from L. pumila.
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