... Page 4. 336 MF Raihana, I. Sopyan, M. Hamdi and S. Ramesh ... The authors gratefully acknowle... more ... Page 4. 336 MF Raihana, I. Sopyan, M. Hamdi and S. Ramesh ... The authors gratefully acknowledge Sr. Toibah Abdul Rahim and Br. Syamsul Kamal Arifin for valuable discussion and kind assistance during experimental works. REFERENCES ...
The use of multiple choice tests as a tool of assessment are popular in many university courses, ... more The use of multiple choice tests as a tool of assessment are popular in many university courses, particularly in the foundation year where there is large number of students taking common subjects such as mathematics or engineering science. Under such circumstances, the answers to the multiple choice questions (MCQs) are written on special forms with blank ovals. These forms are scanned and marking is done by comparing the answers with those inputs by the examiner. Subsequently, the results of the students are tabulated with the aid of customised software. However, this conventional method of administering MCQs is not practicable when the number of students and the number of questions are small e.g. ≤ 100 and ≤ 10, respectively. The present paper addresses this issue and discusses the development of an unconventional, yet an effective method for administering short and simple MCQs as a means of assessing student learning in a focus area of the subject matter. A MCQs test was designed...
In this paper we describe the development and the incorporation of tweening technique in a multim... more In this paper we describe the development and the incorporation of tweening technique in a multimedia tool to enhance learning, visualization and understanding of engineering mechanics concept based on the equations of equilibrium to analyze engineering structures composed of pin-connected members. Tweening technique allows "in-between" images to be created between supplied key frames using linear interpolation where animations were employed to illustrate motions such as movement of the support and rotation of structure. The study revealed that such a multimedia tool could be implemented using multimedia authoring software rather than high level programming language. Assessment based on learners feedback indicated that the developed prototype tool not only increased the learners level of understanding of the mechanics concept but more importantly it provided the means for visualization of the problem via motion and animation.
The development of effective multimedia learning packages (MLP) used by students in their learnin... more The development of effective multimedia learning packages (MLP) used by students in their learning requires the exploitation of a variety of authoring tools. These packages developed using Integrated Development Environments (IDEs) such as C, C++ and Java is difficult and, could give rise to a number of design and development problems. On the other hand, the use of authoring tools such as Director MX TM , Authorware MX TM and Flash MX TM requires one to have a comprehensive knowledge on the capabilities of such tools under different design conditions. This paper addresses and discussed the design and implementation issues pertaining to the development of multimedia learning packages with particular emphasis on engineering. A problem-solving model was adopted and was found to be effective in designing the packages using various authoring tools that allow users to visualize a problem prior to solving it.
The objective of this research is to complement and enhanced traditional tutorial teaching and le... more The objective of this research is to complement and enhanced traditional tutorial teaching and learning by incorporating multimedia technology. In this case study, the development of a PC base virtual experiment for mechanics dynamics problem involving the motion of a projectile that is taught in the second year of the mechanical engineering undergraduate course at University Tenaga Nasional (UNITEN) is described. The developed prototype tool was found to be effective in promoting learning and the outcome of this research revealed that multimedia approach enhanced user understanding of the underlying theory of engineering mechanics, promote interactivity as well as visualization and users are able to solve engineering problem such as motion of a projectile quickly and efficiently.
Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture
In this article, the development of an augmented reality–based robotic work cell is presented, co... more In this article, the development of an augmented reality–based robotic work cell is presented, consisting of a virtual robot arm, conveyor belt, pallet and computer numerical control machine that simulates an actual manufacturing plant environment. The kinematics of the robot arm is realized using Denavit–Hartenberg’s theorem, which enables complete manipulation of the end-effector in three-dimensional space when interacting with other virtual machines. Collision detection is implemented in two areas, namely, modifiable marker–based detection for the robot arm, which detects nearby obstacles as well as integration with object manipulation to pick and place a virtual object around the environment. In addition, an augmented heads-up display overlay displays live information of the current system. The case studies suggest that the proposed system can simulate a collision-free operation while displaying the coordinates of the virtual object, current tool equipped and speed of the convey...
In the present research, nano hydroxyapatite (HA) powder doped with magnesia (MgO) was studied. T... more In the present research, nano hydroxyapatite (HA) powder doped with magnesia (MgO) was studied. The dopant was added to pure HA powder and ball milling was done for 1 hour. Green samples, in the form of discs and rectangular bars, were prepared and consolidated in air at temperatures ranging from 1000 °C to 1300 °C. The sintered samples were characterized to determine the phase stability, relative density, hardness, fracture toughness and Young's modulus. The phase analysis revealed that the HA phase was not disrupted regardless of dopant additions and sintering temperature. It has been revealed that all HA samples achieved >98% relative density when sintered between 1100 °C-1300 °C. However, the addition of 0.5 wt% MgO when sintered at 1100 °C was found to be most beneficial in aiding sintering with samples exhibiting the highest Young's modulus of 122.15 GPa and fracture toughness of 1.64 MPa m1/2 as compared to 116.57 GPa and 1.18 MPa m 1/2 for the undoped HA.
International Journal of Automotive and Mechanical Engineering
A commercially available Y-TZP ceramic powder was fabricated under four different sintering profi... more A commercially available Y-TZP ceramic powder was fabricated under four different sintering profiles in order to investigate the effects of conventional single-stage sintering (SSS) with dwell times of 1 min and 2 h, respectively, compared with two-stage sintering (TSS), on the physical and mechanical properties of Y-TZP. Sintering was performed up to 1400°C at a ramp rate of 10°C/min. It was revealed that samples sintered via TSS yielded better properties than the SSS samples sintered at 1400°C using a dwell time of 2 h. In the hydrothermal ageing test, TSS samples did not undergo low-temperature degradation via the tetragonal to monoclinic phase transformation. Nevertheless, it was found by XRD analysis that Y-TZP ceramics sintered by the SSS method using a short dwell time of 1 min were effective in maintaining tetragonal phase stability after 50 h of exposure to superheated steam conditions.
The sinterability of synthesized nanocrystalline hydroxyapatite (HA) due to the effect of sinteri... more The sinterability of synthesized nanocrystalline hydroxyapatite (HA) due to the effect of sintering temperature was investigated. The starting powder’s synthesis method is a novel wet chemical route and HA green compacts prepared from this powder are sintered at various temperatures in atmospheric condition. It was found that at high sintering temperatures, decomposition of HA phase did not occur. The results shows that the relative density increases to above 98% while the Young’s modulus increases to above 110 GPa when sintered above temperature of 1050oC. However, the hardness and the fracture toughness shows decline when temperature was increased beyond 1000oC. This occurrence is associated with the thermal-activated grain growth process.
The influence of small additions of MnO2 (up to 1 wt. %) on the sintering behaviour of yttria-sta... more The influence of small additions of MnO2 (up to 1 wt. %) on the sintering behaviour of yttria-stabilized zirconia sintered over the temperature range from 1250°C to 1500°C was investigated. It was found that the mechanical properties of Y-TZP were dependent on the dopant amount and sintering temperature. The results revealed that relative densities above 97.5 % of theoretical (i.e. < 5.95 Mg m-3) could be obtained in Y-TZPs sintered at low temperatures, 1250°C and 1300°C, with the additions of ≥ 0.3 wt. % MnO2. In comparison to the undoped samples, the additions of up to 1 wt. % MnO2 and for sintering up to 1350°C was found to be beneficial in enhancing the Vickers hardness of the ceramic. The fracture toughness of Y-TZP however, was found to increase only in the 1 wt. % MnO 2-doped samples when sintered above 1400°C. The relation between the measured mechanical properties is discussed with the emphasis on the role of the manganese oxide.
The sinterability of 3 mol% yttria-tetragonal zirconia polycrystals (Y-TZP) containing small amou... more The sinterability of 3 mol% yttria-tetragonal zirconia polycrystals (Y-TZP) containing small amounts of manganese oxide (MnO2) as sintering aid was investigated over the temperature range of 1250°C to 1500°C. Sintered samples were evaluated to determine bulk density, Young’s modulus, Vickers hardness and fracture toughness. In addition, the tetragonal phase stability of selected samples was evaluated by subjecting the samples to hydrothermal ageing in superheated steam at 180°C/10 bar for periods up to 525 hours. The research showed that the addition of MnO2, particularly ³ 0.3 wt%, was effective in aiding densification and improving the matrix stiffness and hardness when compared to the undoped Y-TZP sintered at temperatures below 1350°C. On the other hand, the fracture toughness of Y-TZP was unaffected by MnO2 addition except for the 1 wt% MnO2-doped Y-TZP samples sintered above 1400°C. The hydrothermal ageing resistance of Y-TZP was significantly improved with the additions of Mn...
In the present study, phase pure forsterite was obtained in sintered bodies from powder mixtures ... more In the present study, phase pure forsterite was obtained in sintered bodies from powder mixtures that did not undergo a heat treatment process prior to sintering. This is contrary to the practice reported in the literature where the powder mixture is normally subjected to a heat treatment at about 1200 °C prior to sintering process. The present results revealed that pure forsterite could be obtained after sintering the powder mixture above 1300 °C. The study found that the mechanical properties of forsterite increased with increasing sintering temperature. A maximum Vickers hardness and fracture toughness of 7.68 GPa and 5.16 MPam1/2 were measured for samples sintered at 1500 °C.
The sinterability of three different commercially available 3 mol% Y-TZP powders was investigated... more The sinterability of three different commercially available 3 mol% Y-TZP powders was investigated. The powders were designated after the manufacturers as Kyoritsu, Dai-ichi and Stanford Y-TZPs. Green samples were compacted and cold isostatically pressed at 200 MPa prior to sintering at temperatures ranging from 1200ºC to 1500°C in air atmosphere. The sintered bodies were examined where appropriate to determine the phase present, bulk density, Young's modulus, hardness and fracture toughness. The results showed that although all the sintered bodies were tetragonal structure, they behave differently with increasing sintering temperature. In general, the Kyoritsu and Dai- ichi Y-TZPs exhibited higher bulk density coupled with better mechanical properties particularly when sintered at temperatures 1350°C to 1450°C. The influence of sintering temperature on the mechanical properties of these ceramics is deliberated in this paper.
ABSTRACT In the present work, pure forsterite (Mg2SiO4) powder was successfully synthesised via b... more ABSTRACT In the present work, pure forsterite (Mg2SiO4) powder was successfully synthesised via ball milling and subsequent heat treatment as an evident from X-ray diffraction analysis. The synthesised powder were formed by powder agglomerates that were made up of loosely packed fine particles. Then, the forsterite green bodies were sintered at 1200 and 1400 degrees C with two different ramp rates (2 and 10 degrees C per minute) via conventional pressureless sintering. No decomposition of forsterite phase was observed at both ramp rates. This study revealed that lower ramp rate (2 degrees C per minute) possessed minor improvement on the mechanical properties only at lower sintering temperature (1200 degrees C), whereas 10 degrees C per minute ramp rate gave a significant enhancement on the mechanical properties of forsterite at 1400 degrees C. A high fracture toughness of similar to 4.9 MPam(1/2) and Vickers hardness of similar to 7.1 GPa were obtained for forsterite samples sintered at 1400 degrees C with a ramp rate of 10 degrees C per minute.
... Page 4. 336 MF Raihana, I. Sopyan, M. Hamdi and S. Ramesh ... The authors gratefully acknowle... more ... Page 4. 336 MF Raihana, I. Sopyan, M. Hamdi and S. Ramesh ... The authors gratefully acknowledge Sr. Toibah Abdul Rahim and Br. Syamsul Kamal Arifin for valuable discussion and kind assistance during experimental works. REFERENCES ...
The use of multiple choice tests as a tool of assessment are popular in many university courses, ... more The use of multiple choice tests as a tool of assessment are popular in many university courses, particularly in the foundation year where there is large number of students taking common subjects such as mathematics or engineering science. Under such circumstances, the answers to the multiple choice questions (MCQs) are written on special forms with blank ovals. These forms are scanned and marking is done by comparing the answers with those inputs by the examiner. Subsequently, the results of the students are tabulated with the aid of customised software. However, this conventional method of administering MCQs is not practicable when the number of students and the number of questions are small e.g. ≤ 100 and ≤ 10, respectively. The present paper addresses this issue and discusses the development of an unconventional, yet an effective method for administering short and simple MCQs as a means of assessing student learning in a focus area of the subject matter. A MCQs test was designed...
In this paper we describe the development and the incorporation of tweening technique in a multim... more In this paper we describe the development and the incorporation of tweening technique in a multimedia tool to enhance learning, visualization and understanding of engineering mechanics concept based on the equations of equilibrium to analyze engineering structures composed of pin-connected members. Tweening technique allows "in-between" images to be created between supplied key frames using linear interpolation where animations were employed to illustrate motions such as movement of the support and rotation of structure. The study revealed that such a multimedia tool could be implemented using multimedia authoring software rather than high level programming language. Assessment based on learners feedback indicated that the developed prototype tool not only increased the learners level of understanding of the mechanics concept but more importantly it provided the means for visualization of the problem via motion and animation.
The development of effective multimedia learning packages (MLP) used by students in their learnin... more The development of effective multimedia learning packages (MLP) used by students in their learning requires the exploitation of a variety of authoring tools. These packages developed using Integrated Development Environments (IDEs) such as C, C++ and Java is difficult and, could give rise to a number of design and development problems. On the other hand, the use of authoring tools such as Director MX TM , Authorware MX TM and Flash MX TM requires one to have a comprehensive knowledge on the capabilities of such tools under different design conditions. This paper addresses and discussed the design and implementation issues pertaining to the development of multimedia learning packages with particular emphasis on engineering. A problem-solving model was adopted and was found to be effective in designing the packages using various authoring tools that allow users to visualize a problem prior to solving it.
The objective of this research is to complement and enhanced traditional tutorial teaching and le... more The objective of this research is to complement and enhanced traditional tutorial teaching and learning by incorporating multimedia technology. In this case study, the development of a PC base virtual experiment for mechanics dynamics problem involving the motion of a projectile that is taught in the second year of the mechanical engineering undergraduate course at University Tenaga Nasional (UNITEN) is described. The developed prototype tool was found to be effective in promoting learning and the outcome of this research revealed that multimedia approach enhanced user understanding of the underlying theory of engineering mechanics, promote interactivity as well as visualization and users are able to solve engineering problem such as motion of a projectile quickly and efficiently.
Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture
In this article, the development of an augmented reality–based robotic work cell is presented, co... more In this article, the development of an augmented reality–based robotic work cell is presented, consisting of a virtual robot arm, conveyor belt, pallet and computer numerical control machine that simulates an actual manufacturing plant environment. The kinematics of the robot arm is realized using Denavit–Hartenberg’s theorem, which enables complete manipulation of the end-effector in three-dimensional space when interacting with other virtual machines. Collision detection is implemented in two areas, namely, modifiable marker–based detection for the robot arm, which detects nearby obstacles as well as integration with object manipulation to pick and place a virtual object around the environment. In addition, an augmented heads-up display overlay displays live information of the current system. The case studies suggest that the proposed system can simulate a collision-free operation while displaying the coordinates of the virtual object, current tool equipped and speed of the convey...
In the present research, nano hydroxyapatite (HA) powder doped with magnesia (MgO) was studied. T... more In the present research, nano hydroxyapatite (HA) powder doped with magnesia (MgO) was studied. The dopant was added to pure HA powder and ball milling was done for 1 hour. Green samples, in the form of discs and rectangular bars, were prepared and consolidated in air at temperatures ranging from 1000 °C to 1300 °C. The sintered samples were characterized to determine the phase stability, relative density, hardness, fracture toughness and Young's modulus. The phase analysis revealed that the HA phase was not disrupted regardless of dopant additions and sintering temperature. It has been revealed that all HA samples achieved >98% relative density when sintered between 1100 °C-1300 °C. However, the addition of 0.5 wt% MgO when sintered at 1100 °C was found to be most beneficial in aiding sintering with samples exhibiting the highest Young's modulus of 122.15 GPa and fracture toughness of 1.64 MPa m1/2 as compared to 116.57 GPa and 1.18 MPa m 1/2 for the undoped HA.
International Journal of Automotive and Mechanical Engineering
A commercially available Y-TZP ceramic powder was fabricated under four different sintering profi... more A commercially available Y-TZP ceramic powder was fabricated under four different sintering profiles in order to investigate the effects of conventional single-stage sintering (SSS) with dwell times of 1 min and 2 h, respectively, compared with two-stage sintering (TSS), on the physical and mechanical properties of Y-TZP. Sintering was performed up to 1400°C at a ramp rate of 10°C/min. It was revealed that samples sintered via TSS yielded better properties than the SSS samples sintered at 1400°C using a dwell time of 2 h. In the hydrothermal ageing test, TSS samples did not undergo low-temperature degradation via the tetragonal to monoclinic phase transformation. Nevertheless, it was found by XRD analysis that Y-TZP ceramics sintered by the SSS method using a short dwell time of 1 min were effective in maintaining tetragonal phase stability after 50 h of exposure to superheated steam conditions.
The sinterability of synthesized nanocrystalline hydroxyapatite (HA) due to the effect of sinteri... more The sinterability of synthesized nanocrystalline hydroxyapatite (HA) due to the effect of sintering temperature was investigated. The starting powder’s synthesis method is a novel wet chemical route and HA green compacts prepared from this powder are sintered at various temperatures in atmospheric condition. It was found that at high sintering temperatures, decomposition of HA phase did not occur. The results shows that the relative density increases to above 98% while the Young’s modulus increases to above 110 GPa when sintered above temperature of 1050oC. However, the hardness and the fracture toughness shows decline when temperature was increased beyond 1000oC. This occurrence is associated with the thermal-activated grain growth process.
The influence of small additions of MnO2 (up to 1 wt. %) on the sintering behaviour of yttria-sta... more The influence of small additions of MnO2 (up to 1 wt. %) on the sintering behaviour of yttria-stabilized zirconia sintered over the temperature range from 1250°C to 1500°C was investigated. It was found that the mechanical properties of Y-TZP were dependent on the dopant amount and sintering temperature. The results revealed that relative densities above 97.5 % of theoretical (i.e. < 5.95 Mg m-3) could be obtained in Y-TZPs sintered at low temperatures, 1250°C and 1300°C, with the additions of ≥ 0.3 wt. % MnO2. In comparison to the undoped samples, the additions of up to 1 wt. % MnO2 and for sintering up to 1350°C was found to be beneficial in enhancing the Vickers hardness of the ceramic. The fracture toughness of Y-TZP however, was found to increase only in the 1 wt. % MnO 2-doped samples when sintered above 1400°C. The relation between the measured mechanical properties is discussed with the emphasis on the role of the manganese oxide.
The sinterability of 3 mol% yttria-tetragonal zirconia polycrystals (Y-TZP) containing small amou... more The sinterability of 3 mol% yttria-tetragonal zirconia polycrystals (Y-TZP) containing small amounts of manganese oxide (MnO2) as sintering aid was investigated over the temperature range of 1250°C to 1500°C. Sintered samples were evaluated to determine bulk density, Young’s modulus, Vickers hardness and fracture toughness. In addition, the tetragonal phase stability of selected samples was evaluated by subjecting the samples to hydrothermal ageing in superheated steam at 180°C/10 bar for periods up to 525 hours. The research showed that the addition of MnO2, particularly ³ 0.3 wt%, was effective in aiding densification and improving the matrix stiffness and hardness when compared to the undoped Y-TZP sintered at temperatures below 1350°C. On the other hand, the fracture toughness of Y-TZP was unaffected by MnO2 addition except for the 1 wt% MnO2-doped Y-TZP samples sintered above 1400°C. The hydrothermal ageing resistance of Y-TZP was significantly improved with the additions of Mn...
In the present study, phase pure forsterite was obtained in sintered bodies from powder mixtures ... more In the present study, phase pure forsterite was obtained in sintered bodies from powder mixtures that did not undergo a heat treatment process prior to sintering. This is contrary to the practice reported in the literature where the powder mixture is normally subjected to a heat treatment at about 1200 °C prior to sintering process. The present results revealed that pure forsterite could be obtained after sintering the powder mixture above 1300 °C. The study found that the mechanical properties of forsterite increased with increasing sintering temperature. A maximum Vickers hardness and fracture toughness of 7.68 GPa and 5.16 MPam1/2 were measured for samples sintered at 1500 °C.
The sinterability of three different commercially available 3 mol% Y-TZP powders was investigated... more The sinterability of three different commercially available 3 mol% Y-TZP powders was investigated. The powders were designated after the manufacturers as Kyoritsu, Dai-ichi and Stanford Y-TZPs. Green samples were compacted and cold isostatically pressed at 200 MPa prior to sintering at temperatures ranging from 1200ºC to 1500°C in air atmosphere. The sintered bodies were examined where appropriate to determine the phase present, bulk density, Young's modulus, hardness and fracture toughness. The results showed that although all the sintered bodies were tetragonal structure, they behave differently with increasing sintering temperature. In general, the Kyoritsu and Dai- ichi Y-TZPs exhibited higher bulk density coupled with better mechanical properties particularly when sintered at temperatures 1350°C to 1450°C. The influence of sintering temperature on the mechanical properties of these ceramics is deliberated in this paper.
ABSTRACT In the present work, pure forsterite (Mg2SiO4) powder was successfully synthesised via b... more ABSTRACT In the present work, pure forsterite (Mg2SiO4) powder was successfully synthesised via ball milling and subsequent heat treatment as an evident from X-ray diffraction analysis. The synthesised powder were formed by powder agglomerates that were made up of loosely packed fine particles. Then, the forsterite green bodies were sintered at 1200 and 1400 degrees C with two different ramp rates (2 and 10 degrees C per minute) via conventional pressureless sintering. No decomposition of forsterite phase was observed at both ramp rates. This study revealed that lower ramp rate (2 degrees C per minute) possessed minor improvement on the mechanical properties only at lower sintering temperature (1200 degrees C), whereas 10 degrees C per minute ramp rate gave a significant enhancement on the mechanical properties of forsterite at 1400 degrees C. A high fracture toughness of similar to 4.9 MPam(1/2) and Vickers hardness of similar to 7.1 GPa were obtained for forsterite samples sintered at 1400 degrees C with a ramp rate of 10 degrees C per minute.
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Papers by Ramesh P. Singh