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Ahmad M.Z.,RMIT University | Ahmad M.Z.,Mechanization and Automation Research Center | Wisitsoraat A.,National Electronics and Computer Technology Center | Zoolfakar A.S.,RMIT University | And 5 more authors.
Sensors and Actuators, B: Chemical | Year: 2013

The gas-sensing performances of tungsten trioxide nanorod thin-films toward reducing and oxidizing analytes are reported. The nanostructured thin-films were RF sputtered, via a glancing angle deposition (GLAD) technique, with different thickness onto conductometric transducers. Thin-film micro-characterization of the surface morphology, chemical compositions and crystal structure by SEM, TEM, XRD and XPS showed that the thin layers contained highly porous, nanocrystalline, stoichiometric WO3 nanorod features with average height varying from 140 to 420 nm and diameter ranging from 40 to 60 nm. Initial vapor sensing test results showed that the ethanol response of WO3 nanorod thin-film tended to increase with decreasing film thickness. The optimized sensor operating temperature for ethanol detection was 300 C with a maximum response of 10 to C2H5OH of 200 ppm for the thinnest film. In contrast, the NO2 response was improved by increasing the WO3 nanorod film thickness, and the thickest films exhibited a very large response of 1075 (10 ppm of NO2) at a relatively low optimized operating temperature of 150 C. Moreover, the developed WO3 based sensors showed good repeatability characteristics when exposed to C2H5OH, but exhibited some poisoning effects when tested in an NO2 environment. The interesting surface structure with very high surface-to-volume ratio of the thin films was reasoned to be responsible for the high and fast response when exposed toward both analytes. © 2013 Elsevier B.V.


Wisitsoorat A.,National Electronics and Computer Technology Center | Ahmad M.Z.,RMIT University | Ahmad M.Z.,Mechanization and Automation Research Center | Yaacob M.H.,University Putra Malaysia | And 5 more authors.
Sensors and Actuators, B: Chemical | Year: 2013

In this work, the optical H2-sensing properties of Pd/tungsten trioxide (WO3) nanorods prepared by rf magnetron sputtering with glancing-angle deposition (GLAD) technique are investigated. From grazing-incidence X-ray diffraction and field emission scanning electron microscopic characterizations, annealed WO3 structure deposited on a quartz substrate at glancing angle of 85 exhibited polycrystalline monoclinic crystal structure with uniform partially isolated columnar nanorod morphology. The nanorods have the average length, diameter and rod separation of around 400 nm, 50 nm and 20 nm, respectively. The developed sensors show remarkable gasochromic absorbance response when exposed to H2. Cumulative absorbance in 650-1000 nm wavelength range is increased by approximately 51% toward H2 with 0.1% concentration in synthetic air, which is more than an order of magnitude higher than that of WO3 dense film prepared by conventional sputtering method. Moreover, WO3 nanorod based sensor is much more promising for practical use due to its much faster response. Therefore, the developed Pd/WO3 nanorod based optical sensors are highly potential for low H2 concentration sensing with highly sensitivity, fast and stable responses and low operating temperature. © 2013 Elsevier B.V.


Humaira M.S.N.,University Malaysia Perlis | Hashim U.,University Malaysia Perlis | Nazwa T.,University Malaysia Perlis | Ten S.T.,University Malaysia Perlis | And 2 more authors.
IEEE International Conference on Semiconductor Electronics, Proceedings, ICSE | Year: 2014

A recent breakthrough in nanotechnology provides a great extent in sensor fabrication and application. The technology has emerged as a powerful technique to minimize the size of devices; amount of materials, energy and time consumption. Nanogap based sensor is one of the sensor that capable of characterizing and quantifying molecules selectively and sensitively with good electrical behavior. In this manuscript, we present a collaboration work between UniMAP, MARDI and UPM in the process development of 40 nm silicon nanogap for sensor application. The process consists of a combination of electron beam lithography (EBL) method and conventional photolithography method. Both methods were for nanogap and electrodes pattern respectively. Silicon on insulator (SOI) substrate was used to fabricate the nanogap structure and gold was used for the electrode. The ability of EBL system to fabricate a gap in nanometer scale with direct lithography technique on SOI substrate gives advantages in this development work. The developed silicon nanogap device was physically characterized with scanning electron microscope (SEM). The sensor application was accomplished by testing the device with different level of pH solutions using a dielectric analyzer. © 2014 IEEE.


Kakahy A.N.N.,University Putra Malaysia | Ahmad D.,University Putra Malaysia | Akhir MD.,Mechanization and Automation Research Center | Sulaiman S.,University Putra Malaysia | Ishak A.,University Putra Malaysia
Applied Mechanics and Materials | Year: 2013

The effects of a rotary slasher with two different shapes of knives (L and Y-shaped) at three cutting speeds (1830, 2066 and 2044 rpm) were studied on percentage of pulverization of sweet potato vine passing through the sieve (< 28 mm2). The results showed that all the treatments were significant at p 〈 0.05 and p 〉 0.01 significance level. The best result was by Y-shaped knife with highest vine pulverized percentage of 82.76% and a mower speed of 2440 rpm had the finest vine pulverized percentage of 90.48%. The best performance for interaction effects between knife shapes and speeds of mower was achieved by the Y-shaped knife and a mower speed of 2440 rpm resulting in an average percentage of 92.62% of pulverized vine. © (2013) Trans Tech Publications, Switzerland.


Ahmad M.Z.,RMIT University | Ahmad M.Z.,Mechanization and Automation Research Center | Golovko V.B.,MacDiarmid Institute for Advanced Materials and Nanotechnology | Adnan R.H.,MacDiarmid Institute for Advanced Materials and Nanotechnology | And 7 more authors.
International Journal of Hydrogen Energy | Year: 2013

Controlled amounts of chemically synthesised gold (Au) nanoclusters were deposited onto tungsten trioxide (WO3) nanostructured thin films as sensors for hydrogen. The Au/WO3 thin films were characterised by XPS, XRD, SEM and TEM. Performance of Au/WO3 films was tested at operating temperatures varying from room temperature to 450 C. It was demonstrated that Au metal loading plays an important role in defining enhancement of the sensor response towards hydrogen. "Less is more" principle applies to the reported here sensors as materials made using lower concentration of Au nanoclusters demonstrated significantly better response. HRTEM images of the Au/WO3 thin films provide evidence that the more active sensors are enriched with smaller Au nanoparticles (≤5 nm). Fast response towards H2 within a wide range of industrially relevant concentrations, excellent baseline stability and signal reproducibility at optimized operating temperature demonstrate feasibility of this novel approach toward fabrication of sensors. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Kakahy A.N.N.,University Putra Malaysia | Ahmad D.,University Putra Malaysia | Akhir M.D.,Mechanization and Automation Research Center | Sulaiman S.,University Putra Malaysia | Ishak A.,University Putra Malaysia
Advanced Materials Research | Year: 2013

A study was conducted to test the effects of three different speeds of 1830, 2066 and 2440 rpm of a mower knife with serrated edges and two different feeding angles of 45° and 90° on the pulverization of sweet potato vines. The results indicated that all the treatments were significant at 99% significance level for the pulverized percentage of sweet potato vines remaining on the sieve. The best result was for the 45° feeding angle with lowest vine pulverized percentage of 47.20%. The second speed of 2066 rpm had the finest vine pulverized percentage of 57.47%. The best performance for overlapping effect between feeding angle and speed of mower was achieved by the 45° feeding angle and a mower speed of 1830 rpm resulting in an average percentage of 44.45% of pulverized vines. © (2013) Trans Tech Publications, Switzerland.


Ahmad M.T.,Mechanization and Automation Research Center | Rani R.A.,Mechanization and Automation Research Center | Hassan A.R.,Mechanization and Automation Research Center
International Journal of Automotive and Mechanical Engineering | Year: 2013

Pineapple transplanting is very laborious work. This process requires 15 workers to plant one hectare of pineapple, which requires 43,500 suckers. The objective of this study was to develop an improved mechanical transplanter for transplanting pineapple suckers. Physical parameters of pineapple suckers, such as weight (g), length (cm), diameter (cm) and canopy (cm) were measured for two varieties, MD2 and N36. A preliminary experiment based on the gripper-type mechanical transplanter was also done. The experiment proved that this transplanter had potential for transplanting pineapple suckers, as it was able to transplant the suckers with the targeted planting distance of 30 cm. However, components such as the roller chain system, the grippers and furrow opener required design improvements. The roller chain system should use 12.5 mm (0.5 in) chain for the whole chain-sprocket system. The gripper should be lengthened to 30 cm to accommodate the uniform pineapple sucker length. The gripper slot should also be widened to about 6 cm. The furrow opener needs to be widened from 8.9 cm to 10.2 cm to accommodate the biggest diameter of pineapple suckers. It is hoped that these design improvements can improve the workability of the mechanical transplanter for transplantation of pineapple suckers. © Universiti Malaysia Pahang.


Kakahy A.N.N.,University Putra Malaysia | Ahmad D.,University Putra Malaysia | Akhir M.D.,Mechanization and Automation Research Center | Sulaiman S.,University Putra Malaysia | Ishak A.,University Putra Malaysia
IOP Conference Series: Materials Science and Engineering | Year: 2013

The effects of different mower speeds (2358, 2440 and 2553 rpm) and different knife angles (30°, 40° and 50°) on sweet potato vine pulverization were studied. The results indicated that all the treatments were significant at p < 0.05 and p < 0.01 significance level for the pulverized percentage of sweet potato vine. The 30° knife angle gave the best result with highest vine pulverized percentage of 54.60 %, and a mower speed of 2553 rpm had the finest vine pulverized percentage of 46.99 %. The best performance for interaction effect between knife angle and speed of mower was achieved by the 30° knife angle and a mower speed of 2440 rpm resulting in an average percentage of 61.27% of pulverized vine. © Published under licence by IOP Publishing Ltd.


Zoolfakar A.S.,RMIT University | Zoolfakar A.S.,University Technology of MARA | Ahmad M.Z.,RMIT University | Ahmad M.Z.,Mechanization and Automation Research Center | And 7 more authors.
Sensors and Actuators, B: Chemical | Year: 2013

We report on ethanol (C2H5OH) vapour sensing devices based on nanostructured cupric oxide (CuO) and cuprous oxide (Cu2O) thin films, which are deposited using RF sputtering at relatively low temperature and power conditions: at 120 C, single stoichiometry CuO and Cu 2O films are deposited using the sputtering power of 200 and 250 W, respectively. At such sputtering conditions CuO films exhibit smaller nanocrystallite base dimensions (~30 nm), in comparison to Cu2O films (~85 nm), which significantly enhance surface area to volume ratio. Both nanostructured CuO and Cu2O gas sensors are able to detect ethanol vapour as low as several ppm and at relatively low operating temperatures of 180 and 260 C, respectively. The sensors showed high sensitivity and repeatability, as well as fast response and recovery towards ethanol vapour. © 2013 Elsevier B.V.


Kakahy A.N.N.,University Putra Malaysia | Ahmad D.,University Putra Malaysia | Akhir M.D.,Mechanization and Automation Research Center | Sulaiman S.,University Putra Malaysia | Ishak A.,University Putra Malaysia
Key Engineering Materials | Year: 2014

Two different shapes of knives (L and Y-shaped) for the rotary slasher with 30° knife cutting angle at three cutting speeds (1830, 2066 and 2044 rpm) were used to indicate their effects on the power consumption for pulverizing sweet potato vine which passed through the sieve (< 28 mm2). The results indicated that all the treatments were significant at p < 0.01 significance level for the power consumption on sweet potato vine pulverizing. The best result was recorded from L-shaped knife with a power consumption of 52.12 Watts for sweet potato vine pulverization. Meanwhile, the best result was for the mower speed at 1830 rpm with the lowest power consumption of 61.23 Watts. The best performance for interaction between knife shapes and the cutting speeds was achieved by the L-shaped knife at 1830 rpm with lowest power consumption of 50.23 Watts at p < 0.01. Copyright © 2014 Trans Tech Publications Ltd, Switzerland.

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