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Papers by noreffendy tamaldin

Graphene is a two-dimensional carbon allotrope that has developed as an extraordinarily flexible ... more Graphene is a two-dimensional carbon allotrope that has developed as an extraordinarily flexible material and has gotten overall consideration on the 21st century. In this concise survey, we have exhibited a portion of the ongoing disclosure of carbon-based materials especially graphene. This paper additionally examined the graphene developing technique that was directed by past research and concentrating on the Chemical Vapor Deposition (CVD) strategy. The tribologicalconduct of graphene at full scale were likewise talked about dependent on past investigation concentrating on the wear and coefficient of grating. A review of full scale tribological properties of broadly utilized strong greases including Diamond like Carbon (DLC), graphite, shapeless carbon, Ultrananochrystalline precious stone, and furthermore graphene oxide were likewise talked about. Outline of the collaboration between steel-to-steel contact and steel tographite/graphene/graphene oxide were additionally talked ab...

Indonesian Journal of Computing, Engineering and Design (IJoCED), 2022

Brazil has a long tradition of bioethanol production from sugarcane. Following the Middle East cr... more Brazil has a long tradition of bioethanol production from sugarcane. Following the Middle East crisis in the 1970s, the oil price increased twofold, doubling Brazil’s spending on oil imports. As a result, the country had to find an alternative type of fuel to reduce its expenditure on conventional petrol fuels. With its vast tropical land conditions, the Brazilian government then put massive effort to establish the infrastructure and research of bioethanol from 1975 and 1989. Research plays a pivotal role in the success of Brazil’s ethanol industry. The country was heavily criticised at the beginning of the programme, but today, Brazil is the second-largest ethanol producer after the USA. Brazil produces the cheapest ethanol in the world and does not depend on fossil fuel to supply its energy demand. Indonesia and Brazil share the same landscape and geographical advantages. This paper aims to discuss the success of the Brazilian bioethanol industry and draw important lessons from it...

PVT solar systems are recently emerging solar technology that allows the simultaneous conversion ... more PVT solar systems are recently emerging solar technology that allows the simultaneous conversion of solar energy into both electricity and heat. The aim of these systems PVT is to improve the electrical efficiency with the cooling system by reducing the temperature of the cell. The performance of PV is reduced with the increase in temperature and use under the advice the absorber collector takes in the excess heat underneath the PV and transfers the heat through the working fluid such as water. The harvested heat is used for low-temperature applications such as domestic hot water supply, water preheating, and space heating. In this paper, the effects of the major control parameters on the thermal and electrical performance of PVT collectors are compiled and reviewed. Figures and tables are provided to give an overall picture of how PVT performance could be improved in terms of these parameters. Although investigators understand the effects of different parameters, the improvement of PVT performance by optimizing these parameters has not been fully realized.

International Journal of Automotive and Mechanical Engineering, 2021

Biodiesel can be utilised in diesel engines without major alteration to the engine; however, its ... more Biodiesel can be utilised in diesel engines without major alteration to the engine; however, its use can lead to engine oil dilution through biodiesel leaking and scraping to the engine oil pan. The objective of this research is to investigate the contamination of biodiesel in engine lubricant oil, and determine the relationship between engine performance and emission for three different blends of palm methyl ester (B10, B20, and B30). To simulate the contamination, the engine oils were blended with biodiesel fuels at 5%, 10%, 15% and 20% by volume and these mixtures were tested on four-ball test equipment. An air-cooled diesel engine was used to analyse the influence of the three biodiesel blends on the output and emission of the diesel engine. The results show that both coefficient of friction and wear scar diameter increased with the increase of biodiesel percentage. The results of engine performance during both sweep test and step test showed that the variation of torque and pow...

Article history: Received 8 May 2019 Received in revised form 27 May 2019 Accepted 4 June 2019 Av... more Article history: Received 8 May 2019 Received in revised form 27 May 2019 Accepted 4 June 2019 Available online 15 July 2019 Commercial solar cells are currently less efficient in converting solar radiation into electricity. Photovoltaic (PV) performance decreases as temperature increases. Many efforts have been made to investigate and develop hybrid PV and thermal collector systems. A photovoltaic thermal (PVT) system generates both electric power and heat simultaneously. A significant amount of work has been carried out on these systems since 1970. Different PVT systems have been invented in the last 30 years. The aim of PVT systems is to improve electrical efficiency using a cooling system by reducing cell temperature, and an absorber collector takes the excess heat underneath the PV system. Then, the heat is transferred through working fluids such as water. The harvested heat is further used in low-temperature applications, including domestic hot water supply, water preheating, ...

This paper presents the effect of the high blending ratio (HBR) biodiesel storage on the acid val... more This paper presents the effect of the high blending ratio (HBR) biodiesel storage on the acid value and flashes point temperature. The samples used, standard diesel (STD), B80, B90, and B100 were stored at temperature24 °C for nine weeks in a box. The acid value and flash point temperature were measured according to the American Society for Testing and Materials (ASTM) procedure. The results show that the acid value and flash point temperature of the samples were increased almost 10% with the rise of 10% biodiesel blending ratio. Under long storage duration, the acid value and flash point temperature for all the samples are nearest to constant. Consequently, there are no significant effect on the acid value and flash point temperature when all the samples were stored in the dark place at room temperature (24°C) for a long period.

Article history: Received 31 March 2019 Received in revised form 23 April 2019 Accepted 30 May 20... more Article history: Received 31 March 2019 Received in revised form 23 April 2019 Accepted 30 May 2019 Available online 6 June 2019 Heat removal factor (FR) is vital in determining the photovoltaic thermal (PVT) system thermal efficiency. (FR) represents the ratio of the actual (useful) heat gain via the heat transfer fluid that flows through a collector to the entire collector surface. In this study, simulations were conducted on three configurations using the PVT new design (dual oscillating absorber) to determine (FR) and thermal efficiency. Using different tube gaps and tube diameters D, the designs were compared using validated model, which was presented using the MATLAB programme theoretical data. The findings indicate that the shape, gap, and diameter of the absorber tubes are crucial to the PVT performance. The study was done under solar radiation level of 300-1000 W/m2 and mass flow rate of 0.01 kg/s at each solar radiation level. The results show that the best thermal efficie...

The purpose of this study is to investigate the stability of nano-oil by pH control in stationary... more The purpose of this study is to investigate the stability of nano-oil by pH control in stationary conditions. The nano-oil was prepared by dispersing an optimal composition of 0.5 vol.% 70 nm hexagonal boron nitride (hBN) nanoparticles in SAE 15W-40 diesel engine oil by sonication technique. Hydrochloric (HCl) acid and Sodium Hydroxide (NaOH) were used as a dispersing agent to determine the stability of the dispersion. The dispersion stability was evaluated by using the sedimentation method with the help of Ultra Violet-Visible (UV-Vis) spectrophotometer. It was demonstrated that the suspension in the alkaline region with a pH value of 11 to 13 was stable over the period of 60 days.

Heliyon, 2020

Consumer interest in privately managed urban transport services in Indonesia are showing a declin... more Consumer interest in privately managed urban transport services in Indonesia are showing a declining trend. On the other hand, the presence of Transportation on Demand (ToD) based on Internet of Things (IoT) has attracted the majority of conventional fleet customers which contribute to the declining trend of occupancy. Therefore, this study aims to present a feasibility study of a small car RE60 Three Passenger and One Driver (3Pþ1D) fourwheeler as an alternative to replace conventional fleets. The Break-Even Point (BEP), Net Present Value (NPV), Internal Rate of Return (IRR), and Payback Period (PP) are analyzed based on vehicle operating data. The analysis shows that there is an additional monthly income flow of IDR 1,533,122 and IDR 2,536,946 from RE60 operations compared to the high and low consumption of fuel from existing fleets, respectively. In conclusion, it is feasible to invest in small car RE60 as a replacement for the existing fleets since the fundamental indicators (BEP, NPV, IRR, and PP) showed positive results before the specified instalment period. Sensitivity analysis also shows good results, NPV shows positive results (>0) although the input conditions are made pessimistic to-30% from NPV base case. The BEP of RE60 will cut distance travelled at 190,670 km and 115,225 km, respectively. NPV of IDR 33,088,000 and IDR 80,841,000 will be obtained at the 60th month after the operation and IRR also enabled good scores, at 2.24% and 4.17%.

Industrial Lubrication and Tribology, 2020

Purpose This paper aims to examine the friction and wear performance of the graphene synthesized ... more Purpose This paper aims to examine the friction and wear performance of the graphene synthesized from fruit cover plastic waste and oil palm fiber (OPF). Design/methodology/approach The graphene was synthesized by using a chemical vapor deposition method, where a copper sheet was used as the substrate. The dry sliding test was performed by using a micro ball-on-disc tribometer at various sliding speeds and applied loads. Findings The results show that both as-grown graphenes decrease the coefficient of friction significantly. Likewise, the wear rate is also lower at higher sliding speed and applied load. For this study, OPF is proposed as the best solid carbon source for synthesizing the graphene. Originality/value The main contribution of this study is opening a new perspective on the potentials of producing graphene from solid waste materials and its effect on the tribological performance. Peer review The peer review history for this article is available at: https://publons.com/pu...

The International Journal of Advanced Manufacturing Technology, 2019

This paper discusses the optimisation of graphene grown from solid waste products, particularly f... more This paper discusses the optimisation of graphene grown from solid waste products, particularly fruit cover plastic waste and oil palm fibre. It involved a method known as chemical vapour deposition, where a copper sheet was used as the substrate. L 9 Taguchi arrays were created based on three parameters, namely, the type of gas, substrate temperature, and growth time. The Raman spectrum analysis was selected as the response, where the I 2D /I G ratio was taken into consideration to determine the type of graphene that was produced (whether single-layered or multi-layered). Then, the optimum graphene coating synthesised was tested under a dry sliding test at different applied loads. According to the signal to noise ratio and analysis of variance, the optimum parameters for growing graphene were 90 min of growing time at a temperature of 1020°C using only argon gas for fruit cover plastic waste, and 30 min of growing time at a temperature of 1000°C using argon and hydrogen gas for oil palm fibre. An error of between 13 and 17% was observed between the experimental result and the predicted value. The tribological performance for both graphenes shows promising potentials as friction reduction materials with OPF coating are suggested as the best type of coating synthesised.

IOP Conference Series: Materials Science and Engineering, 2015

DOI to the publisher's website. • The final author version and the galley proof are versions of t... more DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:

International Journal of Surface Science and Engineering, 2017

The aim of this study was to investigate the tribological effects of nano-based engine oil dilute... more The aim of this study was to investigate the tribological effects of nano-based engine oil diluted with biodiesel fuel. The nano-oil was prepared by disperse an optimal composition 0.5 vol.% of 70 nm hexagonal boron nitride (hBN) nanoparticles in diesel engine oil using sonication technique. Sample was diluted by difference percentages of B100 biodiesel fuel in range of 5-20 vol.%. The tribological test was performed using a four-ball tribometer. It was found that the addition of biodiesel fuel increases the coefficient of friction (COF) and seizure wears as compared with nano-oil. However, there is no significant effect on the extreme pressure (EP) properties, where the seizure for all tested samples starts to occur at 981 N.

MATEC Web of Conferences, 2016

There are various gasoline fuel producers available in Malaysia. The effects of fuel variations f... more There are various gasoline fuel producers available in Malaysia. The effects of fuel variations from different manufacturers on vehicle performance have always been a debate among users and currently the facts still remains inconclusive. Hence, this study focuses on analyzing various RON95 fuel brands available in the Malaysian market and finding the differences towards engine performance. In terms of engine output, the important data of power (hp) and torque (Nm) will be gathered by using an engine dynamometer. Another data that would also be taken into account is the knocking where the relative knock index can be measured in percentage using the knock sensor accelerometer. Results have shown that the performance of different fuel brands tested are indeed different albeit by only a small margin even though all fuels are categorized with the same octane rating. The power and torque results also imply that both are influenced by the amount of vibration generated due to engine knocking. Based from the overall outcome, consumers would not need to only focus on a certain type of gasoline brand as all differentiates the engine performance marginally.

Advanced Materials Research, 2016

The aim of this study is to investigate the friction properties of waste cooking oil (WCO) with b... more The aim of this study is to investigate the friction properties of waste cooking oil (WCO) with banana peel broth. The WCO was purified using a physical technique. Several weight percentages of 15 wt.%, 30 wt.% and 45 wt.% of banana peel broth was dispersed in WCO using ultrasonic homogenizer. Span 80, as a surfactant, were added to the blends. The tribological test was performed using a four-ball tribometer according to the ASTM standards. At early stage, between 0-1200 seconds, it was found that the presence of banana peel broth in WCO reduces the friction coefficient. However, after a certain time, the oil film breakdown and instantly increased the friction coefficient. By observation of worn surfaces, it can be suggested that WCO with 30 wt.% banana peel broth could be a good blends for this study. As a conclusion, this study proposes that the banana peel broth could improve the tribological properties of WCO in mild conditions.

Stringent pollutant regulations on diesel-powered vehicles have resulted in the development of ne... more Stringent pollutant regulations on diesel-powered vehicles have resulted in the development of new technologies to reduce emission of nitrogen oxides (NOx). The urea Selective Catalyst Reduction (SCR) system and Lean NOx Trap (LNT) have become the two promising solutions to this problem. Whilst the LNT results in a fuel penalty due to periodic regeneration, the SCR system with aqueous urea solution or ammonia gas reductants could provide a better solution with higher NOx reduction efficiency. This thesis describes an experimental investigation which has been designed for comparing the effect NOx abatement of a SCR system with AdBlue urea spray and ammonia gas at 5% and 4% concentration. For this study, a SCR exhaust system comprising of a diesel particulate filter (DPF), a diesel oxidation catalyst (DOC) and SCR catalysts was tested on a steady state, direct injection 1998 cc diesel engine. It featured an expansion can, nozzle and diffuser arrangement for a controlled flow profile for CFD model validation. Four different lengths of SCR catalyst were tested for a space velocity study. Chemiluminescence (CLD) based ammonia analysers have been used to provide high resolution NO, NO2 and NH3 measurements across the SCR exhaust system. By measuring at the exit of the SCR bricks, the NO and NO2 profiles within the bricks were found. Comparison of the measurements between spray and gas lead to insights of the behaviour of the droplets upstream and within the SCR bricks. From the analysis, it was deduced that around half to three quarters of the droplets from the urea spray remain unconverted at the entry of the first SCR brick. Approximately 200 ppm of potential ammonia was released from the urea spray in the first SCR brick to react with NOx. The analysis also shows between 10 to 100 ppm of potential ammonia survived through the first brick in droplet form for cases from NOx-matched spray input to excess spray. Measurements show NOx reduction was complete after the second SCR bricks. Experimental and CFD prediction showed breakthrough of all species for the short brick with gas injection due to the high space velocity. The long brick gas cases predictions gave reasonable agreement with experimental results. NO2 conversion efficiency was found higher than NO which contradicts with the fast SCR reaction kinetics. Transient response was observed in both cases during the NOx reduction, ammonia absorption and desorption process. From the transient analysis an estimate of the ammonia storage capacity of the bricks was derived. The amount of ammonia slippage was obtained through numerical integration of the ammonia slippage curve using an excel spreadsheet. Comparing the time constant for the spray and gas cases, showed a slightly faster time response from the gas for both NOx reduction and ammonia slippage

Applied Mechanics and Materials, 2015

The aim of this paper is to investigate the effects of voltage flow (V) in the alkaline electroly... more The aim of this paper is to investigate the effects of voltage flow (V) in the alkaline electrolyser system and the pH value (pH) of the electrolyte used in the electrolyser. The output measurement of both investigated factors in in the flow rate of the hydrogen gas produced by the system per minute (ml/min). The voltage flow was altered in the system by altering the voltage supply from the workbench power supply ranging from 11V to 14V. The pH value of the electrolyte solution in the electrolyser was altered by the addition of Potassium Hydroxide (KOH) in the distilled water. The pH value samples of the tested solution ranging from 13.0 to 14.0 pH value due to the limitation of the electrolyser used in this experiment. The results found that, the hydrogen gas produced per minute increases with voltage flow in the system. The flow rate of the hydrogen gas produced however only increases when the solution’s pH value reaches at 14 pH level and unreactive below the value.

Applied Mechanics and Materials, 2015

In this paper, storage effect on biodiesel properties for high blending ratio and the emission ar... more In this paper, storage effect on biodiesel properties for high blending ratio and the emission are evaluated. The blend level of biodiesel is denoted as B, followed by the percentages of pure biodiesel. The samples used are conventional diesel (STD), B80, B90 and B100 were stored at ambient temperature (24 °C) for nine week. The properties of biodiesel, acid value, flash point, viscosity, density and water content were measured according to ASTM D6751 biodiesel fuel standard. Results show there are no significant effects on it properties while stored in long duration at ambient temperature. Meanwhile, increasing biodiesel ratio is found to enhance the combustion process, resulting in decreased the HC for emissions.

This paper presents the experimental study on the tribological and engine performances of nano-oi... more This paper presents the experimental study on the tribological and engine performances of nano-oil. In this study, the nano-oil was prepared by dispersing an optimal composition (0.5 vol.%) of 70nm hexagonal boron nitride (hBN) nanoparticles in conventional diesel engine oil by sonication technique. The tribological study was performed using a four-ball tribometer, while the single cylinder diesel engine performance test was conducted using 20 hp, air cooled type, eddy current dynamometer. By comparing with conventional diesel engine oil, it was found that the nano-oil is effective in reducing the coefficient of friction and enhancing the engine performance, simultaneously reduces frictional wear on the contact surfaces of engine components. The results presented here may facilitate improvements in the energy efficiency of tribological systems towards a sustainable future for green technology advancement.

Graphene is a two-dimensional carbon allotrope that has developed as an extraordinarily flexible ... more Graphene is a two-dimensional carbon allotrope that has developed as an extraordinarily flexible material and has gotten overall consideration on the 21st century. In this concise survey, we have exhibited a portion of the ongoing disclosure of carbon-based materials especially graphene. This paper additionally examined the graphene developing technique that was directed by past research and concentrating on the Chemical Vapor Deposition (CVD) strategy. The tribologicalconduct of graphene at full scale were likewise talked about dependent on past investigation concentrating on the wear and coefficient of grating. A review of full scale tribological properties of broadly utilized strong greases including Diamond like Carbon (DLC), graphite, shapeless carbon, Ultrananochrystalline precious stone, and furthermore graphene oxide were likewise talked about. Outline of the collaboration between steel-to-steel contact and steel tographite/graphene/graphene oxide were additionally talked ab...

Indonesian Journal of Computing, Engineering and Design (IJoCED), 2022

Brazil has a long tradition of bioethanol production from sugarcane. Following the Middle East cr... more Brazil has a long tradition of bioethanol production from sugarcane. Following the Middle East crisis in the 1970s, the oil price increased twofold, doubling Brazil’s spending on oil imports. As a result, the country had to find an alternative type of fuel to reduce its expenditure on conventional petrol fuels. With its vast tropical land conditions, the Brazilian government then put massive effort to establish the infrastructure and research of bioethanol from 1975 and 1989. Research plays a pivotal role in the success of Brazil’s ethanol industry. The country was heavily criticised at the beginning of the programme, but today, Brazil is the second-largest ethanol producer after the USA. Brazil produces the cheapest ethanol in the world and does not depend on fossil fuel to supply its energy demand. Indonesia and Brazil share the same landscape and geographical advantages. This paper aims to discuss the success of the Brazilian bioethanol industry and draw important lessons from it...

PVT solar systems are recently emerging solar technology that allows the simultaneous conversion ... more PVT solar systems are recently emerging solar technology that allows the simultaneous conversion of solar energy into both electricity and heat. The aim of these systems PVT is to improve the electrical efficiency with the cooling system by reducing the temperature of the cell. The performance of PV is reduced with the increase in temperature and use under the advice the absorber collector takes in the excess heat underneath the PV and transfers the heat through the working fluid such as water. The harvested heat is used for low-temperature applications such as domestic hot water supply, water preheating, and space heating. In this paper, the effects of the major control parameters on the thermal and electrical performance of PVT collectors are compiled and reviewed. Figures and tables are provided to give an overall picture of how PVT performance could be improved in terms of these parameters. Although investigators understand the effects of different parameters, the improvement of PVT performance by optimizing these parameters has not been fully realized.

International Journal of Automotive and Mechanical Engineering, 2021

Biodiesel can be utilised in diesel engines without major alteration to the engine; however, its ... more Biodiesel can be utilised in diesel engines without major alteration to the engine; however, its use can lead to engine oil dilution through biodiesel leaking and scraping to the engine oil pan. The objective of this research is to investigate the contamination of biodiesel in engine lubricant oil, and determine the relationship between engine performance and emission for three different blends of palm methyl ester (B10, B20, and B30). To simulate the contamination, the engine oils were blended with biodiesel fuels at 5%, 10%, 15% and 20% by volume and these mixtures were tested on four-ball test equipment. An air-cooled diesel engine was used to analyse the influence of the three biodiesel blends on the output and emission of the diesel engine. The results show that both coefficient of friction and wear scar diameter increased with the increase of biodiesel percentage. The results of engine performance during both sweep test and step test showed that the variation of torque and pow...

Article history: Received 8 May 2019 Received in revised form 27 May 2019 Accepted 4 June 2019 Av... more Article history: Received 8 May 2019 Received in revised form 27 May 2019 Accepted 4 June 2019 Available online 15 July 2019 Commercial solar cells are currently less efficient in converting solar radiation into electricity. Photovoltaic (PV) performance decreases as temperature increases. Many efforts have been made to investigate and develop hybrid PV and thermal collector systems. A photovoltaic thermal (PVT) system generates both electric power and heat simultaneously. A significant amount of work has been carried out on these systems since 1970. Different PVT systems have been invented in the last 30 years. The aim of PVT systems is to improve electrical efficiency using a cooling system by reducing cell temperature, and an absorber collector takes the excess heat underneath the PV system. Then, the heat is transferred through working fluids such as water. The harvested heat is further used in low-temperature applications, including domestic hot water supply, water preheating, ...

This paper presents the effect of the high blending ratio (HBR) biodiesel storage on the acid val... more This paper presents the effect of the high blending ratio (HBR) biodiesel storage on the acid value and flashes point temperature. The samples used, standard diesel (STD), B80, B90, and B100 were stored at temperature24 °C for nine weeks in a box. The acid value and flash point temperature were measured according to the American Society for Testing and Materials (ASTM) procedure. The results show that the acid value and flash point temperature of the samples were increased almost 10% with the rise of 10% biodiesel blending ratio. Under long storage duration, the acid value and flash point temperature for all the samples are nearest to constant. Consequently, there are no significant effect on the acid value and flash point temperature when all the samples were stored in the dark place at room temperature (24°C) for a long period.

Article history: Received 31 March 2019 Received in revised form 23 April 2019 Accepted 30 May 20... more Article history: Received 31 March 2019 Received in revised form 23 April 2019 Accepted 30 May 2019 Available online 6 June 2019 Heat removal factor (FR) is vital in determining the photovoltaic thermal (PVT) system thermal efficiency. (FR) represents the ratio of the actual (useful) heat gain via the heat transfer fluid that flows through a collector to the entire collector surface. In this study, simulations were conducted on three configurations using the PVT new design (dual oscillating absorber) to determine (FR) and thermal efficiency. Using different tube gaps and tube diameters D, the designs were compared using validated model, which was presented using the MATLAB programme theoretical data. The findings indicate that the shape, gap, and diameter of the absorber tubes are crucial to the PVT performance. The study was done under solar radiation level of 300-1000 W/m2 and mass flow rate of 0.01 kg/s at each solar radiation level. The results show that the best thermal efficie...

The purpose of this study is to investigate the stability of nano-oil by pH control in stationary... more The purpose of this study is to investigate the stability of nano-oil by pH control in stationary conditions. The nano-oil was prepared by dispersing an optimal composition of 0.5 vol.% 70 nm hexagonal boron nitride (hBN) nanoparticles in SAE 15W-40 diesel engine oil by sonication technique. Hydrochloric (HCl) acid and Sodium Hydroxide (NaOH) were used as a dispersing agent to determine the stability of the dispersion. The dispersion stability was evaluated by using the sedimentation method with the help of Ultra Violet-Visible (UV-Vis) spectrophotometer. It was demonstrated that the suspension in the alkaline region with a pH value of 11 to 13 was stable over the period of 60 days.

Heliyon, 2020

Consumer interest in privately managed urban transport services in Indonesia are showing a declin... more Consumer interest in privately managed urban transport services in Indonesia are showing a declining trend. On the other hand, the presence of Transportation on Demand (ToD) based on Internet of Things (IoT) has attracted the majority of conventional fleet customers which contribute to the declining trend of occupancy. Therefore, this study aims to present a feasibility study of a small car RE60 Three Passenger and One Driver (3Pþ1D) fourwheeler as an alternative to replace conventional fleets. The Break-Even Point (BEP), Net Present Value (NPV), Internal Rate of Return (IRR), and Payback Period (PP) are analyzed based on vehicle operating data. The analysis shows that there is an additional monthly income flow of IDR 1,533,122 and IDR 2,536,946 from RE60 operations compared to the high and low consumption of fuel from existing fleets, respectively. In conclusion, it is feasible to invest in small car RE60 as a replacement for the existing fleets since the fundamental indicators (BEP, NPV, IRR, and PP) showed positive results before the specified instalment period. Sensitivity analysis also shows good results, NPV shows positive results (>0) although the input conditions are made pessimistic to-30% from NPV base case. The BEP of RE60 will cut distance travelled at 190,670 km and 115,225 km, respectively. NPV of IDR 33,088,000 and IDR 80,841,000 will be obtained at the 60th month after the operation and IRR also enabled good scores, at 2.24% and 4.17%.

Industrial Lubrication and Tribology, 2020

Purpose This paper aims to examine the friction and wear performance of the graphene synthesized ... more Purpose This paper aims to examine the friction and wear performance of the graphene synthesized from fruit cover plastic waste and oil palm fiber (OPF). Design/methodology/approach The graphene was synthesized by using a chemical vapor deposition method, where a copper sheet was used as the substrate. The dry sliding test was performed by using a micro ball-on-disc tribometer at various sliding speeds and applied loads. Findings The results show that both as-grown graphenes decrease the coefficient of friction significantly. Likewise, the wear rate is also lower at higher sliding speed and applied load. For this study, OPF is proposed as the best solid carbon source for synthesizing the graphene. Originality/value The main contribution of this study is opening a new perspective on the potentials of producing graphene from solid waste materials and its effect on the tribological performance. Peer review The peer review history for this article is available at: https://publons.com/pu...

The International Journal of Advanced Manufacturing Technology, 2019

This paper discusses the optimisation of graphene grown from solid waste products, particularly f... more This paper discusses the optimisation of graphene grown from solid waste products, particularly fruit cover plastic waste and oil palm fibre. It involved a method known as chemical vapour deposition, where a copper sheet was used as the substrate. L 9 Taguchi arrays were created based on three parameters, namely, the type of gas, substrate temperature, and growth time. The Raman spectrum analysis was selected as the response, where the I 2D /I G ratio was taken into consideration to determine the type of graphene that was produced (whether single-layered or multi-layered). Then, the optimum graphene coating synthesised was tested under a dry sliding test at different applied loads. According to the signal to noise ratio and analysis of variance, the optimum parameters for growing graphene were 90 min of growing time at a temperature of 1020°C using only argon gas for fruit cover plastic waste, and 30 min of growing time at a temperature of 1000°C using argon and hydrogen gas for oil palm fibre. An error of between 13 and 17% was observed between the experimental result and the predicted value. The tribological performance for both graphenes shows promising potentials as friction reduction materials with OPF coating are suggested as the best type of coating synthesised.

IOP Conference Series: Materials Science and Engineering, 2015

DOI to the publisher's website. • The final author version and the galley proof are versions of t... more DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:

International Journal of Surface Science and Engineering, 2017

The aim of this study was to investigate the tribological effects of nano-based engine oil dilute... more The aim of this study was to investigate the tribological effects of nano-based engine oil diluted with biodiesel fuel. The nano-oil was prepared by disperse an optimal composition 0.5 vol.% of 70 nm hexagonal boron nitride (hBN) nanoparticles in diesel engine oil using sonication technique. Sample was diluted by difference percentages of B100 biodiesel fuel in range of 5-20 vol.%. The tribological test was performed using a four-ball tribometer. It was found that the addition of biodiesel fuel increases the coefficient of friction (COF) and seizure wears as compared with nano-oil. However, there is no significant effect on the extreme pressure (EP) properties, where the seizure for all tested samples starts to occur at 981 N.

MATEC Web of Conferences, 2016

There are various gasoline fuel producers available in Malaysia. The effects of fuel variations f... more There are various gasoline fuel producers available in Malaysia. The effects of fuel variations from different manufacturers on vehicle performance have always been a debate among users and currently the facts still remains inconclusive. Hence, this study focuses on analyzing various RON95 fuel brands available in the Malaysian market and finding the differences towards engine performance. In terms of engine output, the important data of power (hp) and torque (Nm) will be gathered by using an engine dynamometer. Another data that would also be taken into account is the knocking where the relative knock index can be measured in percentage using the knock sensor accelerometer. Results have shown that the performance of different fuel brands tested are indeed different albeit by only a small margin even though all fuels are categorized with the same octane rating. The power and torque results also imply that both are influenced by the amount of vibration generated due to engine knocking. Based from the overall outcome, consumers would not need to only focus on a certain type of gasoline brand as all differentiates the engine performance marginally.

Advanced Materials Research, 2016

The aim of this study is to investigate the friction properties of waste cooking oil (WCO) with b... more The aim of this study is to investigate the friction properties of waste cooking oil (WCO) with banana peel broth. The WCO was purified using a physical technique. Several weight percentages of 15 wt.%, 30 wt.% and 45 wt.% of banana peel broth was dispersed in WCO using ultrasonic homogenizer. Span 80, as a surfactant, were added to the blends. The tribological test was performed using a four-ball tribometer according to the ASTM standards. At early stage, between 0-1200 seconds, it was found that the presence of banana peel broth in WCO reduces the friction coefficient. However, after a certain time, the oil film breakdown and instantly increased the friction coefficient. By observation of worn surfaces, it can be suggested that WCO with 30 wt.% banana peel broth could be a good blends for this study. As a conclusion, this study proposes that the banana peel broth could improve the tribological properties of WCO in mild conditions.

Stringent pollutant regulations on diesel-powered vehicles have resulted in the development of ne... more Stringent pollutant regulations on diesel-powered vehicles have resulted in the development of new technologies to reduce emission of nitrogen oxides (NOx). The urea Selective Catalyst Reduction (SCR) system and Lean NOx Trap (LNT) have become the two promising solutions to this problem. Whilst the LNT results in a fuel penalty due to periodic regeneration, the SCR system with aqueous urea solution or ammonia gas reductants could provide a better solution with higher NOx reduction efficiency. This thesis describes an experimental investigation which has been designed for comparing the effect NOx abatement of a SCR system with AdBlue urea spray and ammonia gas at 5% and 4% concentration. For this study, a SCR exhaust system comprising of a diesel particulate filter (DPF), a diesel oxidation catalyst (DOC) and SCR catalysts was tested on a steady state, direct injection 1998 cc diesel engine. It featured an expansion can, nozzle and diffuser arrangement for a controlled flow profile for CFD model validation. Four different lengths of SCR catalyst were tested for a space velocity study. Chemiluminescence (CLD) based ammonia analysers have been used to provide high resolution NO, NO2 and NH3 measurements across the SCR exhaust system. By measuring at the exit of the SCR bricks, the NO and NO2 profiles within the bricks were found. Comparison of the measurements between spray and gas lead to insights of the behaviour of the droplets upstream and within the SCR bricks. From the analysis, it was deduced that around half to three quarters of the droplets from the urea spray remain unconverted at the entry of the first SCR brick. Approximately 200 ppm of potential ammonia was released from the urea spray in the first SCR brick to react with NOx. The analysis also shows between 10 to 100 ppm of potential ammonia survived through the first brick in droplet form for cases from NOx-matched spray input to excess spray. Measurements show NOx reduction was complete after the second SCR bricks. Experimental and CFD prediction showed breakthrough of all species for the short brick with gas injection due to the high space velocity. The long brick gas cases predictions gave reasonable agreement with experimental results. NO2 conversion efficiency was found higher than NO which contradicts with the fast SCR reaction kinetics. Transient response was observed in both cases during the NOx reduction, ammonia absorption and desorption process. From the transient analysis an estimate of the ammonia storage capacity of the bricks was derived. The amount of ammonia slippage was obtained through numerical integration of the ammonia slippage curve using an excel spreadsheet. Comparing the time constant for the spray and gas cases, showed a slightly faster time response from the gas for both NOx reduction and ammonia slippage

Applied Mechanics and Materials, 2015

The aim of this paper is to investigate the effects of voltage flow (V) in the alkaline electroly... more The aim of this paper is to investigate the effects of voltage flow (V) in the alkaline electrolyser system and the pH value (pH) of the electrolyte used in the electrolyser. The output measurement of both investigated factors in in the flow rate of the hydrogen gas produced by the system per minute (ml/min). The voltage flow was altered in the system by altering the voltage supply from the workbench power supply ranging from 11V to 14V. The pH value of the electrolyte solution in the electrolyser was altered by the addition of Potassium Hydroxide (KOH) in the distilled water. The pH value samples of the tested solution ranging from 13.0 to 14.0 pH value due to the limitation of the electrolyser used in this experiment. The results found that, the hydrogen gas produced per minute increases with voltage flow in the system. The flow rate of the hydrogen gas produced however only increases when the solution’s pH value reaches at 14 pH level and unreactive below the value.

Applied Mechanics and Materials, 2015

In this paper, storage effect on biodiesel properties for high blending ratio and the emission ar... more In this paper, storage effect on biodiesel properties for high blending ratio and the emission are evaluated. The blend level of biodiesel is denoted as B, followed by the percentages of pure biodiesel. The samples used are conventional diesel (STD), B80, B90 and B100 were stored at ambient temperature (24 °C) for nine week. The properties of biodiesel, acid value, flash point, viscosity, density and water content were measured according to ASTM D6751 biodiesel fuel standard. Results show there are no significant effects on it properties while stored in long duration at ambient temperature. Meanwhile, increasing biodiesel ratio is found to enhance the combustion process, resulting in decreased the HC for emissions.

This paper presents the experimental study on the tribological and engine performances of nano-oi... more This paper presents the experimental study on the tribological and engine performances of nano-oil. In this study, the nano-oil was prepared by dispersing an optimal composition (0.5 vol.%) of 70nm hexagonal boron nitride (hBN) nanoparticles in conventional diesel engine oil by sonication technique. The tribological study was performed using a four-ball tribometer, while the single cylinder diesel engine performance test was conducted using 20 hp, air cooled type, eddy current dynamometer. By comparing with conventional diesel engine oil, it was found that the nano-oil is effective in reducing the coefficient of friction and enhancing the engine performance, simultaneously reduces frictional wear on the contact surfaces of engine components. The results presented here may facilitate improvements in the energy efficiency of tribological systems towards a sustainable future for green technology advancement.