The effects of non-thermal plasma （NTP） treatment on biomass in the form of pulverized palmbased empty fruit bunches （EFB） are investigated. Specifically, this study investigates the effects of NTP treatment on th...The effects of non-thermal plasma （NTP） treatment on biomass in the form of pulverized palmbased empty fruit bunches （EFB） are investigated. Specifically, this study investigates the effects of NTP treatment on the surface reactivity, morphology, oxygen-to-carbon （O/C） ratio of the EFB at varying treatment times. The surface reactivity is determined by the reaction of antioxidant functional groups or reactive species with 2,2-diphenyl-l-picrylhydrazyl （DPPH）. By measuring the concentration of the DPPH with a spectrophotometer, the change in the amount of antioxidant functional groups can be measured to determine the surface reactivity. The reactions of the various lignin components in the EFB with respect to the NTP treatment are discussed by qualitatively assessing the changes in the Fourier transform infrared （FTIR） spectra. The surface morphology is examined by a scanning electron microscope. To determine the amount of oxygen deposited on the EFB by the air-based NTP treatment, the oxygen and carbon contents are measured by an energy dispersive x-ray detector to determine the O/C ratio. The results show that the NTP reactor produced reactive species such as atomic oxygen and ozone, increasing the surface reactivity and chemical scavenging rate of the EFB. Consequently, the surface morphology changed, with an observed rougher surface from the images of the EFB samples. The change in the appearance of the surface is accompanied by a high O/C ratio, and is caused by reactions of certain components of lignin due to the NTP treatment, The lignin component that was modified is believed to be syringyl, as the syringyl portion in the lignin of EFBs is higher compared to the other components. Syringyl components are detected in the range of F-FIR wavenumbers of 1109-1363 cm-1. With increasing NTP treatment times, the absorbance （of the peaks in the PTIR spectra） for syringyl related C-H and lignin associated C=C bonds decreases as the syringyl decomposes. The resulting release of carboxyl compounds increases the absorbance for the carbonyl C=O group. The results show that NTP treatment is able to modify the surface properties of EFB, and that the surface reactivity can be increased to improve their conversion and processing efficiencies.展开更多
This paper presentsa voltage control strategy for power distribution systems with interconnected renewable energy based distributed generators (DGs). The control strategy coordinating conventional voltage control devi...This paper presentsa voltage control strategy for power distribution systems with interconnected renewable energy based distributed generators (DGs). The control strategy coordinating conventional voltage control devices and reactive power from DG.A mixed-integer nonlinear programming problem was formulated and solved by particle swarm optimization (PSO). The code is written using DigSILENT programming language (DPL) and implemented inside DigSILENT power factory simulation software. All system constraints and operating limits are considered. The optimal power flow based approach can incorporate various uncertainties such as intermittent power characteristics and varying load demand. The proposed method is tested using real distribution network to demonstrate its effectiveness. The merits of the proposed method over the classical local-based control are presented in the simulation results. It is demonstrated that the proposed method is capable of keeping the system voltage within operating limit. Power losses is at the same time is minimized in comparison to the losses using conventional method.展开更多
Non-thermal plasma（NTP） devices produce excited and radical species that have higher energy levels than their ground state and are utilized for various applications. There are various types of NTP devices, with diel...Non-thermal plasma（NTP） devices produce excited and radical species that have higher energy levels than their ground state and are utilized for various applications. There are various types of NTP devices, with dielectric barrier discharge（DBD） reactors being widely used. These DBD devices vary in geometrical configuration and operating parameters, making a comparison of their performance in terms of discharge power characteristics difficult. Therefore, this study proposes a dimensionless parameter that is related to the geometrical features, and is a function of the discharge power with respect to the frequency, voltage, and capacitance of a DBD. The dimensionless parameter, in the form of a ratio of the discharge energy per cycle to the gap capacitive energy, will be useful for engineers and designers to compare the energy characteristics of devices systematically, and could also be used for scaling up DBD devices.From the results in this experiment and from the literature, different DBD devices are categorized into three separate groups according to different levels of the energy ratio. The larger DBD devices have lower energy ratios due to their lower estimated surface discharge areas and capacitive reactance. Therefore, the devices can be categorized according to the energy ratio due to the effects of the geometrical features of the DBD devices, since it affects the surface discharge area and capacitance of the DBD. The DBD devices are also categorized into three separate groups using the Kriegseis factor, but the categorization is different from that of the energy ratio.展开更多
This paper presentsand describes harmonic measurement and analysis of studying harmonic propagation during electric vehicle (EV) charging. The measurement study is performed on a golf cart and two modern type of EVs. ...This paper presentsand describes harmonic measurement and analysis of studying harmonic propagation during electric vehicle (EV) charging. The measurement study is performed on a golf cart and two modern type of EVs. Harmonics from a single EV charging and a group of EV charging was measured. The voltage and current waveform during the charging was captured and analyzed to investigate the harmonic components that exist in the electrical system. Total current harmonic distortion (THDi) and total voltage harmonic distortion (THDi) were both calculated. Modern electric vehicles are found to release low THDi but higher THDv compared to a golf cart. On the measurement study during charging of? a group of EV, it is found that the summation of THD is not linear with a number of vehicles. The finding of the study reveals that harmonic contamination from EV charging on electrical grid is not as critical as thought by most of power system researchers and engineers.展开更多
Background The increasing demand for large-scale hydroelectric dam development in tropical developing countries has led to significant land-use changes that impact biodiversity,particularly in megadiverse countries,su...Background The increasing demand for large-scale hydroelectric dam development in tropical developing countries has led to significant land-use changes that impact biodiversity,particularly in megadiverse countries,such as Malaysia.Although many recent infrastructure projects incorporate sustainable concepts for wildlife monitoring and management,studies on the impacts of habitat fragmentation on ground-dwelling birds during the development phase remain scarce.This study aimed to assess the response of forest bird communities,particularly the ground-dwelling birds,across different phases of hydroelectric dam development using infrared camera traps.We collected data from 14 sampling sites in Nenggiri hydroelectric dam catchment area for 25 months across three developmental phases:pre-logging,logging,and construction.Results We recorded 1045 occurrences of 33 bird species,including the critically endangered Malayan Crestless Fireback Lophura erythrophthalma and the endangered Malayan Peacock-Pheasant Polyplectron malacense.There were significant changes between phases,with a notable decrease in the number of pheasants detected,such as the Great Argus Argusianus argus and Malayan Crested Fireback Lophura rufa,especially during the construction phase.Indicator species analysis(Ind Val)identified seven species showing strong associations(p<0.05)with specific development phases,including the Barred Cuckoo-Dove Macropygia unchall and Great Argus for the pre-logging phase.Conclusion These results highlight the vulnerability of ground-dwelling birds,particularly pheasants,to habitat disturbances from large-scale development activities.We propose incorporating camera trap assessments into major infrastructure projects to identify key locations of conservation-priority bird species,and to inform targeted rescue or translocation efforts,particularly during high-impact phases such as habitat clearance and dam impoundment.展开更多
Background Mineral-rich licks are known to provide mineral supplements to wildlife species,including mammals.Artificial salt licks have been provided as habitat enrichment in protected areas and secondary forests in P...Background Mineral-rich licks are known to provide mineral supplements to wildlife species,including mammals.Artificial salt licks have been provided as habitat enrichment in protected areas and secondary forests in Peninsular Malaysia since 2012.However,few studies have investigated artificial salt licks,particularly their mineral composition and roles in different habitats.We used 40 camera traps to assess mammal species diversity and assemblages at 20 salt licks(nine natural and 11 artificial licks)in three forest reserves in Peninsular Malaysia.Nine mineral elements from water and soil samples from natural and artificial licks in primary and secondary forests were analysed.Results Twenty-nine mammal species were identified across salt licks,with 16 species being salt lick users,including eight herbivorous,five frugivorous and three carnivorous mammals,most of which moved in groups and solitarily.The mammal species assemblages across both salt lick and habitat types demonstrated a predominantly nested pattern,with herbivorous and frugivorous mammals being the primary users.The artificial salt licks in both habitats showcased the same feeding guilds including species that are resilient to habitat changes.The visitation frequency at both types of licks and habitats suggests that each salt lick user had its own preferences for minerals from salt lick water and soil.Conclusions This study suggests that artificial licks may be as effective as natural licks in providing minerals to many mammal species both in primary and secondary forests.Thus,they could be used to enrich degraded habitats.Enriching degraded habitats is essential for supporting the ecosystem,especially in carbon reduction,biodiversity conservation and connectivity between degraded forests and intact forests.展开更多
Background:Habitat degradation is known to have a major impact on the composition of bird communities,yet how these communities recover following such disturbance is less understood.This study examined bird community ...Background:Habitat degradation is known to have a major impact on the composition of bird communities,yet how these communities recover following such disturbance is less understood.This study examined bird community changes from pre-logging to recovery over the course of habitat disturbance caused by the development of the Hulu Terengganu Hydroelectric Dam Project in Peninsular Malaysia,between 2007 and 2018.Bird surveys were conducted using point count observations and mist netting in the dam area from the prelogging phase until the operation phase.Results:It was observed that while bird species significantly declined after large-scale habitat clearance between the pre-logging and construction phases,they showed positive signs of recovery from the inundation to operation phases.These findings indicate that the bird community is still recovering,and the permanent loss of habitat required by most of the original species has not occurred,as evidenced by recolonisation.Bird species composition differed across phases due to varying habitat conditions.The turnover rate and immigration rate(recolonisation and newly recorded species)were higher between the construction and operation phases.It was also observed that insectivorous birds were more heavily affected than others by changes to the landscape,which highlights the versatility,survivability and tolerance of certain species to extreme disturbance and habitat modification.Conclusion:Although the operation phase showed an incremental change in bird species richness due to recolonisation and newly recorded species,this value remains far from that of the pre-logging phase.We predict that bird species recovery will continue to increase for some time before reaching a plateau among the newly created islands,reservoir and catchment area of the dam.展开更多
The Association of Southeast Asian Nations is blessed with agricultural resources,and with the growing population,it will continue to prosper,which follows the abundance of agricultural biomass.Lignocellulosic biomass...The Association of Southeast Asian Nations is blessed with agricultural resources,and with the growing population,it will continue to prosper,which follows the abundance of agricultural biomass.Lignocellulosic biomass attracted researchers’interest in extracting bio-oil from these wastes.However,the resulting bio-oil has low heating values and undesirable physical properties.Hence,co-pyrolysis with plastic or polymer wastes is adopted to improve the yield and quality of the bio-oil.Furthermore,with the spread of the novel coronavirus,the surge of single-use plastic waste such as disposable medical face mask,can potentially set back the previous plastic waste reduction measures.Therefore,studies of existing technologies and techniques are referred in exploring the potential of disposable medical face mask waste as a candidate for co-pyrolysis with biomass.Process parameters,utilisation of catalysts and technologies are key factors in improving and optimising the process to achieve commercial standard of liquid fuel.Catalytic copyrolysis involves a series of complex mechanisms,which cannot be explained using simple iso-conversional models.Hence,advanced conversional models are introduced,followed by the evolutionary models and predictive models,which can solve the non-linear catalytic copyrolysis reaction kinetics.The outlook and challenges for the topic are discussed in detail.展开更多
基金Tenaga Nasional Berhad (Malaysia) for funding this research (TNBR/SF 240/2016)
文摘The effects of non-thermal plasma （NTP） treatment on biomass in the form of pulverized palmbased empty fruit bunches （EFB） are investigated. Specifically, this study investigates the effects of NTP treatment on the surface reactivity, morphology, oxygen-to-carbon （O/C） ratio of the EFB at varying treatment times. The surface reactivity is determined by the reaction of antioxidant functional groups or reactive species with 2,2-diphenyl-l-picrylhydrazyl （DPPH）. By measuring the concentration of the DPPH with a spectrophotometer, the change in the amount of antioxidant functional groups can be measured to determine the surface reactivity. The reactions of the various lignin components in the EFB with respect to the NTP treatment are discussed by qualitatively assessing the changes in the Fourier transform infrared （FTIR） spectra. The surface morphology is examined by a scanning electron microscope. To determine the amount of oxygen deposited on the EFB by the air-based NTP treatment, the oxygen and carbon contents are measured by an energy dispersive x-ray detector to determine the O/C ratio. The results show that the NTP reactor produced reactive species such as atomic oxygen and ozone, increasing the surface reactivity and chemical scavenging rate of the EFB. Consequently, the surface morphology changed, with an observed rougher surface from the images of the EFB samples. The change in the appearance of the surface is accompanied by a high O/C ratio, and is caused by reactions of certain components of lignin due to the NTP treatment, The lignin component that was modified is believed to be syringyl, as the syringyl portion in the lignin of EFBs is higher compared to the other components. Syringyl components are detected in the range of F-FIR wavenumbers of 1109-1363 cm-1. With increasing NTP treatment times, the absorbance （of the peaks in the PTIR spectra） for syringyl related C-H and lignin associated C=C bonds decreases as the syringyl decomposes. The resulting release of carboxyl compounds increases the absorbance for the carbonyl C=O group. The results show that NTP treatment is able to modify the surface properties of EFB, and that the surface reactivity can be increased to improve their conversion and processing efficiencies.
文摘This paper presentsa voltage control strategy for power distribution systems with interconnected renewable energy based distributed generators (DGs). The control strategy coordinating conventional voltage control devices and reactive power from DG.A mixed-integer nonlinear programming problem was formulated and solved by particle swarm optimization (PSO). The code is written using DigSILENT programming language (DPL) and implemented inside DigSILENT power factory simulation software. All system constraints and operating limits are considered. The optimal power flow based approach can incorporate various uncertainties such as intermittent power characteristics and varying load demand. The proposed method is tested using real distribution network to demonstrate its effectiveness. The merits of the proposed method over the classical local-based control are presented in the simulation results. It is demonstrated that the proposed method is capable of keeping the system voltage within operating limit. Power losses is at the same time is minimized in comparison to the losses using conventional method.
基金Tenaga Nasional Berhad(Malaysia)for funding of this research(TNBR/SF195/2015 and TNBR/SF240/2016)
文摘Non-thermal plasma（NTP） devices produce excited and radical species that have higher energy levels than their ground state and are utilized for various applications. There are various types of NTP devices, with dielectric barrier discharge（DBD） reactors being widely used. These DBD devices vary in geometrical configuration and operating parameters, making a comparison of their performance in terms of discharge power characteristics difficult. Therefore, this study proposes a dimensionless parameter that is related to the geometrical features, and is a function of the discharge power with respect to the frequency, voltage, and capacitance of a DBD. The dimensionless parameter, in the form of a ratio of the discharge energy per cycle to the gap capacitive energy, will be useful for engineers and designers to compare the energy characteristics of devices systematically, and could also be used for scaling up DBD devices.From the results in this experiment and from the literature, different DBD devices are categorized into three separate groups according to different levels of the energy ratio. The larger DBD devices have lower energy ratios due to their lower estimated surface discharge areas and capacitive reactance. Therefore, the devices can be categorized according to the energy ratio due to the effects of the geometrical features of the DBD devices, since it affects the surface discharge area and capacitance of the DBD. The DBD devices are also categorized into three separate groups using the Kriegseis factor, but the categorization is different from that of the energy ratio.
文摘This paper presentsand describes harmonic measurement and analysis of studying harmonic propagation during electric vehicle (EV) charging. The measurement study is performed on a golf cart and two modern type of EVs. Harmonics from a single EV charging and a group of EV charging was measured. The voltage and current waveform during the charging was captured and analyzed to investigate the harmonic components that exist in the electrical system. Total current harmonic distortion (THDi) and total voltage harmonic distortion (THDi) were both calculated. Modern electric vehicles are found to release low THDi but higher THDv compared to a golf cart. On the measurement study during charging of? a group of EV, it is found that the summation of THD is not linear with a number of vehicles. The finding of the study reveals that harmonic contamination from EV charging on electrical grid is not as critical as thought by most of power system researchers and engineers.
基金funded by Tenaga Nasional Berhad Research(TNBR)grant number ST-2022–019
文摘Background The increasing demand for large-scale hydroelectric dam development in tropical developing countries has led to significant land-use changes that impact biodiversity,particularly in megadiverse countries,such as Malaysia.Although many recent infrastructure projects incorporate sustainable concepts for wildlife monitoring and management,studies on the impacts of habitat fragmentation on ground-dwelling birds during the development phase remain scarce.This study aimed to assess the response of forest bird communities,particularly the ground-dwelling birds,across different phases of hydroelectric dam development using infrared camera traps.We collected data from 14 sampling sites in Nenggiri hydroelectric dam catchment area for 25 months across three developmental phases:pre-logging,logging,and construction.Results We recorded 1045 occurrences of 33 bird species,including the critically endangered Malayan Crestless Fireback Lophura erythrophthalma and the endangered Malayan Peacock-Pheasant Polyplectron malacense.There were significant changes between phases,with a notable decrease in the number of pheasants detected,such as the Great Argus Argusianus argus and Malayan Crested Fireback Lophura rufa,especially during the construction phase.Indicator species analysis(Ind Val)identified seven species showing strong associations(p<0.05)with specific development phases,including the Barred Cuckoo-Dove Macropygia unchall and Great Argus for the pre-logging phase.Conclusion These results highlight the vulnerability of ground-dwelling birds,particularly pheasants,to habitat disturbances from large-scale development activities.We propose incorporating camera trap assessments into major infrastructure projects to identify key locations of conservation-priority bird species,and to inform targeted rescue or translocation efforts,particularly during high-impact phases such as habitat clearance and dam impoundment.
基金provided by the Tenaga Nasional Berhad Research(TNBR)Sdn Bhd under research codes ST-2017-009,ST-2017-007 and ST-2022-019
文摘Background Mineral-rich licks are known to provide mineral supplements to wildlife species,including mammals.Artificial salt licks have been provided as habitat enrichment in protected areas and secondary forests in Peninsular Malaysia since 2012.However,few studies have investigated artificial salt licks,particularly their mineral composition and roles in different habitats.We used 40 camera traps to assess mammal species diversity and assemblages at 20 salt licks(nine natural and 11 artificial licks)in three forest reserves in Peninsular Malaysia.Nine mineral elements from water and soil samples from natural and artificial licks in primary and secondary forests were analysed.Results Twenty-nine mammal species were identified across salt licks,with 16 species being salt lick users,including eight herbivorous,five frugivorous and three carnivorous mammals,most of which moved in groups and solitarily.The mammal species assemblages across both salt lick and habitat types demonstrated a predominantly nested pattern,with herbivorous and frugivorous mammals being the primary users.The artificial salt licks in both habitats showcased the same feeding guilds including species that are resilient to habitat changes.The visitation frequency at both types of licks and habitats suggests that each salt lick user had its own preferences for minerals from salt lick water and soil.Conclusions This study suggests that artificial licks may be as effective as natural licks in providing minerals to many mammal species both in primary and secondary forests.Thus,they could be used to enrich degraded habitats.Enriching degraded habitats is essential for supporting the ecosystem,especially in carbon reduction,biodiversity conservation and connectivity between degraded forests and intact forests.
基金funded by Tenaga Nasional Berhad Research(TNBR),grant number ST-2017-010.
文摘Background:Habitat degradation is known to have a major impact on the composition of bird communities,yet how these communities recover following such disturbance is less understood.This study examined bird community changes from pre-logging to recovery over the course of habitat disturbance caused by the development of the Hulu Terengganu Hydroelectric Dam Project in Peninsular Malaysia,between 2007 and 2018.Bird surveys were conducted using point count observations and mist netting in the dam area from the prelogging phase until the operation phase.Results:It was observed that while bird species significantly declined after large-scale habitat clearance between the pre-logging and construction phases,they showed positive signs of recovery from the inundation to operation phases.These findings indicate that the bird community is still recovering,and the permanent loss of habitat required by most of the original species has not occurred,as evidenced by recolonisation.Bird species composition differed across phases due to varying habitat conditions.The turnover rate and immigration rate(recolonisation and newly recorded species)were higher between the construction and operation phases.It was also observed that insectivorous birds were more heavily affected than others by changes to the landscape,which highlights the versatility,survivability and tolerance of certain species to extreme disturbance and habitat modification.Conclusion:Although the operation phase showed an incremental change in bird species richness due to recolonisation and newly recorded species,this value remains far from that of the pre-logging phase.We predict that bird species recovery will continue to increase for some time before reaching a plateau among the newly created islands,reservoir and catchment area of the dam.
基金The authors would like to acknowledge the technical support from Curtin University Malaysia,Swinburne University of Technology,Universiti Teknologi PETRONAS(UTP),and Manipal University Jaipur.Besides that,M.X.J.Wee would like to acknowledge the full funding support from the Curtin Malaysia Postgraduate Research Studentship(CMPRS)for the PhD study.
文摘The Association of Southeast Asian Nations is blessed with agricultural resources,and with the growing population,it will continue to prosper,which follows the abundance of agricultural biomass.Lignocellulosic biomass attracted researchers’interest in extracting bio-oil from these wastes.However,the resulting bio-oil has low heating values and undesirable physical properties.Hence,co-pyrolysis with plastic or polymer wastes is adopted to improve the yield and quality of the bio-oil.Furthermore,with the spread of the novel coronavirus,the surge of single-use plastic waste such as disposable medical face mask,can potentially set back the previous plastic waste reduction measures.Therefore,studies of existing technologies and techniques are referred in exploring the potential of disposable medical face mask waste as a candidate for co-pyrolysis with biomass.Process parameters,utilisation of catalysts and technologies are key factors in improving and optimising the process to achieve commercial standard of liquid fuel.Catalytic copyrolysis involves a series of complex mechanisms,which cannot be explained using simple iso-conversional models.Hence,advanced conversional models are introduced,followed by the evolutionary models and predictive models,which can solve the non-linear catalytic copyrolysis reaction kinetics.The outlook and challenges for the topic are discussed in detail.
