Chien-wei Chen | National Cheng Kung University (original) (raw)
Papers by Chien-wei Chen
2008 IEEE International Conference on Sensor Networks, Ubiquitous, and Trustworthy Computing (sutc 2008), 2008
While DSP's are now widely adopted in many embedded systems in the cost minimiza... more While DSP's are now widely adopted in many embedded systems in the cost minimization and the resolving of computing needs of various multimedia applications, little work is done for energy-efficient real-time job scheduling over DSP's. As motivated by the needs, a set of sliding-window- based algorithms are proposed. A sequence of time points and their corresponding processor speeds is generated to run jobs of a periodic task on the DSP, such as that for the decoding of an H.264 stream. An online DVS scheme for energy minimization with constrained buffer size consideration is proposed, and the capability of the scheme is evaluated by a series of experiments over real and synthesized traces. It was shown that the energy saving can be up to 44%, and prediction errors were not significant enough to result in more than 3% in deadline missing.
2008 IEEE International Joint Conference on Neural Networks (IEEE World Congress on Computational Intelligence), 2008
Since 1980, the hypertension and diabetes mellitus in metabolic syndrome have appeared in the top... more Since 1980, the hypertension and diabetes mellitus in metabolic syndrome have appeared in the top ten causes of death every year in Taiwan. This research aims to study metabolic syndrome related disease by using data mining technique, and to understand the strength of association between diabetes mellitus, hypertension and hyperlipidemia. The data of this research came from the National Health
Journal of Information Science and Engineering, 2007
Embedded software systems are usually custom designed and are close systems in terms of software ... more Embedded software systems are usually custom designed and are close systems in terms of software design and deployment. One example is the Vehicle Information Sys- tem (VIS), in which several components gather vehicle information such as RPM and fuel tank level, and are tightly coupled with the embedded hardware. Several projects have been started by commercial software companies or passionate
Journal of the Taiwan Institute of Chemical Engineers, 2009
Octahydro-1H-benzofuro[3,2-e]isoquinolin-9-ols, which contain the ACNO partial structure of morph... more Octahydro-1H-benzofuro[3,2-e]isoquinolin-9-ols, which contain the ACNO partial structure of morphine, have been found to retain potent analgesic activity. [4] and [5] The N-cyclopropylmethyl analog 1 (J-6549) displayed potent oral analgesic and narcotic-antagonism activity and ...
Lecture Notes in Computer Science, 2006
... Based on augmented panorama, we developed a stereoscopic kiosk [12] for virtual museum, which... more ... Based on augmented panorama, we developed a stereoscopic kiosk [12] for virtual museum, which consists of two display devices: one is a touch screen and the other is a stereoscopic display. ... Lo, WY, Tsai, YP, Chen, CW, Hung, YP: Stereoscopic Kiosk for Virtual Museum. ...
In this paper, we present a stereoscopic kiosk for virtual museum, which combines techniques of s... more In this paper, we present a stereoscopic kiosk for virtual museum, which combines techniques of stereoscopic displays, image-based rendering, virtual reality, and augmented reality. In our kiosk system, artifacts are presented as object movies, and can be integrated with both image-based panoramas and geometry-based scenes for constructing virtual museum. Two display devices are used in the kiosk: one is a touch screen, and the other is a stereoscopic display. Through the touch screen, the users can arbitrarily navigate in the virtual museum, select artifacts, and interactively view the detail information of the selected artifact. Once an artifact on the touch screen is selected, the stereoscopic object movie of the selected artifact will be synchronously shown in the stereoscopic display, which can provide the user a better experience in browsing 3D artifact.
Transportation Research Part E: Logistics and Transportation Review, 2010
In this study, a mathematical model that integrates spatial and temporal dimensions is developed ... more In this study, a mathematical model that integrates spatial and temporal dimensions is developed for strategic planning of future bioethanol supply chain systems. The planning objective is to minimize the cost of the entire supply chain of biofuel from biowaste feedstock fields to end users over the entire planning horizon, simultaneously satisfying demand, resource, and technology constraints. This model is used to evaluate the economic potential and infrastructure requirements for bioethanol production from eight waste biomass resources in California as a case study. It is found that, through careful supply chain design, biowaste-based ethanol production can be sustained at a compatible cost around $1.1 per gallon.
Polymer Journal, 2008
New alternating copolymers of poly(2,7-(9,9 0 -dihexylfluorene)-alt-3,9-(5,11-di(2-ethylhexyl)-in... more New alternating copolymers of poly(2,7-(9,9 0 -dihexylfluorene)-alt-3,9-(5,11-di(2-ethylhexyl)-indolo[3,2-b]carbazole)) (PFp-In) and poly(2,7-(9,9 0 -dihexylfluorene)-alt-2,8-(5,11-di(2-ethylhexyl)-indolo[3,2-b]carbazole)) (PF-m-In) were synthesized by palladium-catalyzed Suzuki coupling polymerization and characterized for the applications of light-emitting diodes and field effect transistors (FET). The incorporation of indolocarbazole into polyfluorene could not only enhance hole transporting properties but also thermal properties. The para-linkage, PF-p-In, facilitates -electron delocalization and thus has a lower optical band gap and a higher emission maximum than those of the meta linkage, PF-m-In. The electroluminescence devices based on PF-p-In and PF-m-In as the emissive layer show a similar maximum luminance but with different emissive colors of green and blue, respectively. The FET hole mobilities of PF-p-In and PF-m-In are 6:73 Â 10 À5 and 1:50 Â 10 À4 cm 2 /VÁs, respectively, which are significantly higher than that of polyfluorene. The present study demonstrates the electronic and optoelectronic properties of polyfluorene enhanced by incorporating hole transporting indolocarbazole with different linkages.
Journal of Polymer Science Part A: Polymer Chemistry, 2004
Two new diamines, 2,4-diaminotriphenylamine (3) and N-(2,4-diaminophenyl)carbazole (4), were synt... more Two new diamines, 2,4-diaminotriphenylamine (3) and N-(2,4-diaminophenyl)carbazole (4), were synthesized via the cesium fluoride-mediated aromatic substitution reactions of 1-fluoro-2,4-dinitrobenzene with diphenylamine and carbazole, followed by palladium-catalyzed hydrazine reduction. Amorphous and soluble aramids having pendent diphenylamino and carbazolyl groups were prepared by the phosphorylation polycondensation of aromatic dicarboxylic acids with diamines 3 and 4, respectively. The aramids derived from diamine 3 had sufficiently high molecular weights to permit the casting of flexible and tough films. They exhibited excellent mechanical properties and moderately high softening temperatures in the 221-298°C range. However, the reactions of diamine 4 with aromatic diacids gave relatively lower molecular weights products that could not afford flexible films. For a comparative purpose, the parent aramids derived from m-phenylenediamine and aromatic diacids were also prepared and characterized.
International Journal of Hydrogen Energy, 2008
Optimization is applied to identify the least-cost sequence of hydrogen infrastructure build-up i... more Optimization is applied to identify the least-cost sequence of hydrogen infrastructure build-up in Southern California during 2010-2060. Given an exogenous demand, the model generates temporal and spatial decisions for building a hydrogen infrastructure, in terms of when, where, at what sizes and by what technologies, that minimize the net present value of technology, environment, and fuel accessibility costs. The least-cost sequence is then analyzed with respect to technology deployment, delivered hydrogen cost, capital requirements, subsidy need, subsidy capacity, and CO2 mitigation.
International Journal of Hydrogen Energy, 2008
The problem of hydrogen station location is often studied through understanding refueling behavio... more The problem of hydrogen station location is often studied through understanding refueling behavior or reviewing the experience of gasoline stations. Driven by the notion "where you drive more is where you more likely need refueling", this paper develops a new approach where station siting is treated as a fuel-travel-back problem and the only required data is VMT distribution. Such a fueltravel-back problem is a typical transportation problem and is solved as mix-integerprogramming model. When the total fuel-travel-back time is minimized, so is the average refueling travel time of a random motorist, for which theoretical deduction is provided. The model is applied to derive an optimal station roll-out scheme for Southern California. The results show that, if station size constraints are relaxed, only 18% of existing gas station number is needed to achieve the current fuel accessibility of gasoline in the region. Fewer stations lead to larger station size, suggesting a need to re-examine the current speculation on designs of hydrogen station and distribution system and to conduct more regional studies for discovery of optimistic and pessimistic regions for hydrogen. The results also indicate that early stations should be located strategically and even at low-demand locations, which is contradictory to existing proposition.
International Journal of Business Information Systems, 2011
ABSTRACT
Fuel, 2008
The purpose of this study was to investigate the dependence of mercury emissions on coal ranks an... more The purpose of this study was to investigate the dependence of mercury emissions on coal ranks and electric utility boilers equipped with Fabric Filter Baghouses (FF). A comparison of mercury emission rates and fly ash properties was made between a circulating Fluidized ...
Environmental Science & Technology, 2010
The formation of sulfur trioxide (SO 3 ) in coal-fired utility boilers can have negative effects ... more The formation of sulfur trioxide (SO 3 ) in coal-fired utility boilers can have negative effects on boiler performance and operation, such as fouling and corrosion of equipment, efficiency loss in the air preheater (APH), increase in stack opacity, and the formation of PM 2.5 . Sulfur trioxide can also compete with mercury when bonding with injected activated carbons. Tests in a lab-scale reactor confirmed there are major interferences between fly ash and SO 3 during SO 3 sampling. A modified SO 3 procedure to maximize the elimination of measurement biases, based on the inertial-filter-sampling and the selective-condensation-collecting of SO 3 , was applied in SO 3 tests in three full-scale utility boilers. For the two units burning bituminous coal, SO 3 levels starting at 20 to 25 ppmv at the inlet to the selective catalytic reduction (SCR), increased slightly across the SCR, owing to catalytic conversion of SO 2 to SO 3, and then declined in other air pollutant control device (APCD) modules downstream to approximately 5 ppmv and 15 ppmv at the two sites, respectively. In the unit burning sub-bituminous coal, the much lower initial concentration of SO 3 estimated to be approximately 1.5 ppmv at the inlet to the SCR was reduced to about 0.8 ppmv across the SCR and to about 0.3 ppmv at the exit of the wet flue gas desulfurization (WFGD). The SO 3 removal efficiency across the WFGD scrubbers at the three sites was generally 35% or less. Reductions in SO 3 across either the APH or the dry electrostatic precipitator (ESP) in units burning high-sulfur bituminous coal were attributed to operating temperatures being below the dew point of SO 3 .
Energy & Fuels, 2009
A systematic investigation of sorbent-trap sampling, which is a method that uses paired sorbent t... more A systematic investigation of sorbent-trap sampling, which is a method that uses paired sorbent traps to measure total vapor phase mercury (Hg), was carried out at two coal-fired power plants. The objective of the study was to evaluate the effects (if any) on data quality when the following aspects of the sorbent trap method are varied: (a) sorbent trap configuration; (b) sampling time; and (c) analytical technique. Also, the performance of a speciating sorbent trap (i.e., a trap capable of separating elemental Hg from oxidized Hg), developed by the Western Kentucky University's Institute for Combustion Science and Environmental Technology (ICSET), was evaluated by direct comparison against the Ontario Hydro (OH) reference method. Flue gas samples were taken using both "regular" and modified sorbent trap measurement systems. The regular sorbent trap systems used a dual-trap, in-stack sampling technique. The modified systems were equipped with either inertial or cyclone probes and used paired, out-of-stack sorbent traps. Both short-term (1.5 h) and long-term (18 h to 10 days) samples were collected. The OH method was run concurrently during the short-term test runs, to provide reference Hg concentrations. At one facility, mercury concentration data from continuous emission monitoring systems were also recorded during the sorbent trap sampling runs. After sampling, the conventional (nonspeciating) sorbent traps were analyzed for Hg, using either a direct combustion method or a wet-chemistry analytical method (i.e., microwaveassisted digestion coupled with cold vapor atomic absorption spectroscopy). The speciating traps were analyzed only by the direct combustion method. All of the sorbent trap data collected in the study were evaluated with respect to relative accuracy, relative deviation of paired traps, and mercury breakthrough. The in-stack and out-of-stack sampling methods produced satisfactory relative accuracy results for both the short-term and long-term testing. For the short-term tests, the in-stack sampling results compared more favorably to the OH method than did the out-of-stack results. The relative deviation between the paired traps was considerably higher for the short-term out-of-stack tests than for the long-term tests. A one-way analysis of variance (ANOVA), showed a statistically significant difference (p < 0.1) between the direct combustion and wet-chemistry analytical methods used in the study; the results from the direct combustion method were consistently higher than the wet-chemistry results. The evaluation of the speciating mercury sorbent trap demonstrated that the trap is capable of providing reasonably accurate total mercury concentrations and speciation data that are somewhat comparable to data obtained with the OH method. Although the results of the study were informative and promising, further evaluation of both the out-of-stack sampling methods and the speciating sorbent trap is recommended.
Energy & Fuels, 2007
An investigation of speciated mercury transformation with the addition of hydrogen bromide (HBr) ... more An investigation of speciated mercury transformation with the addition of hydrogen bromide (HBr) at elevated temperatures was conducted in a slipstream reactor with real flue gas atmospheres. A real flue gas atmosphere is composed of bituminous coal (with high sulfur ...
Energy & Fuels, 2008
Six mercury continuous emission monitoring (CEM) systems provided by two leading mercury (Hg) CEM... more Six mercury continuous emission monitoring (CEM) systems provided by two leading mercury (Hg) CEM system manufacturers were tested at five coal combustion utilities. The linearity, response time, day-to-day stability, efficiency of the Hg speciation modules, and ...
Chemical Engineering Journal, 2010
o-Toluidine is used primarily in the manufacture of dyestuffs, and also in the production of rubb... more o-Toluidine is used primarily in the manufacture of dyestuffs, and also in the production of rubber, chemicals, and pesticides and as a curing agent for epoxy resin systems. It is considered to be toxic and carcinogenic. This study uses the Box-Behnken statistical experiment design to investigate the degradation of o-toluidine by the photo-Fenton process. The effects of ferrous ion dosage, hydrogen peroxide concentration and UVA irradiation were selected as factors in the Box-Behnken design experiment, while, o-toluidine and COD removal efficiency were considered as response functions. Results show that ferrous ion and hydrogen peroxide concentrations were the main parameters affecting the o-toluidine and COD removal, while the number of UVA lamps had a slight effect on the reaction. From the Box-Behnken statistical design prediction, the optimum condition for removing 100% of o-toluidine and 74% of COD was 1.2 mM of ferrous ion, 8 mM of hydrogen peroxide and UVA 85.7 W/m 3 at pH 3.
Analytica Chimica Acta, 2010
Coal and fly ash contain many elements. These elements exist in different forms which may change ... more Coal and fly ash contain many elements. These elements exist in different forms which may change throughout the coal combustion process. There are several processes, including X-ray techniques and leaching techniques by which studies have attempted to assess the form of a particular element in a sample. This work focuses on determining the leachability of selected elements sequentially leached in four extraction solutions: water, 1M ammonium acetate, 3M hydrochloric acid and 50% hydrofluoric acid. The emphasis is on evaluating the steps involved in the leaching process with the mass recovery for each element being the basis for evaluation. The total amount of each element that will leach out under the given extraction condition is presented as a fraction of the total present in the material. The materials evaluated were NIST coal and fly ash standards. The elements measured in this study include aluminum, barium, beryllium, calcium, chromium, cobalt, iron, magnesium, manganese, nickel, potassium, sodium, strontium, vanadium and zinc.
2008 IEEE International Conference on Sensor Networks, Ubiquitous, and Trustworthy Computing (sutc 2008), 2008
While DSP&amp;#x27;s are now widely adopted in many embedded systems in the cost minimiza... more While DSP&amp;#x27;s are now widely adopted in many embedded systems in the cost minimization and the resolving of computing needs of various multimedia applications, little work is done for energy-efficient real-time job scheduling over DSP&amp;#x27;s. As motivated by the needs, a set of sliding-window- based algorithms are proposed. A sequence of time points and their corresponding processor speeds is generated to run jobs of a periodic task on the DSP, such as that for the decoding of an H.264 stream. An online DVS scheme for energy minimization with constrained buffer size consideration is proposed, and the capability of the scheme is evaluated by a series of experiments over real and synthesized traces. It was shown that the energy saving can be up to 44%, and prediction errors were not significant enough to result in more than 3% in deadline missing.
2008 IEEE International Joint Conference on Neural Networks (IEEE World Congress on Computational Intelligence), 2008
Since 1980, the hypertension and diabetes mellitus in metabolic syndrome have appeared in the top... more Since 1980, the hypertension and diabetes mellitus in metabolic syndrome have appeared in the top ten causes of death every year in Taiwan. This research aims to study metabolic syndrome related disease by using data mining technique, and to understand the strength of association between diabetes mellitus, hypertension and hyperlipidemia. The data of this research came from the National Health
Journal of Information Science and Engineering, 2007
Embedded software systems are usually custom designed and are close systems in terms of software ... more Embedded software systems are usually custom designed and are close systems in terms of software design and deployment. One example is the Vehicle Information Sys- tem (VIS), in which several components gather vehicle information such as RPM and fuel tank level, and are tightly coupled with the embedded hardware. Several projects have been started by commercial software companies or passionate
Journal of the Taiwan Institute of Chemical Engineers, 2009
Octahydro-1H-benzofuro[3,2-e]isoquinolin-9-ols, which contain the ACNO partial structure of morph... more Octahydro-1H-benzofuro[3,2-e]isoquinolin-9-ols, which contain the ACNO partial structure of morphine, have been found to retain potent analgesic activity. [4] and [5] The N-cyclopropylmethyl analog 1 (J-6549) displayed potent oral analgesic and narcotic-antagonism activity and ...
Lecture Notes in Computer Science, 2006
... Based on augmented panorama, we developed a stereoscopic kiosk [12] for virtual museum, which... more ... Based on augmented panorama, we developed a stereoscopic kiosk [12] for virtual museum, which consists of two display devices: one is a touch screen and the other is a stereoscopic display. ... Lo, WY, Tsai, YP, Chen, CW, Hung, YP: Stereoscopic Kiosk for Virtual Museum. ...
In this paper, we present a stereoscopic kiosk for virtual museum, which combines techniques of s... more In this paper, we present a stereoscopic kiosk for virtual museum, which combines techniques of stereoscopic displays, image-based rendering, virtual reality, and augmented reality. In our kiosk system, artifacts are presented as object movies, and can be integrated with both image-based panoramas and geometry-based scenes for constructing virtual museum. Two display devices are used in the kiosk: one is a touch screen, and the other is a stereoscopic display. Through the touch screen, the users can arbitrarily navigate in the virtual museum, select artifacts, and interactively view the detail information of the selected artifact. Once an artifact on the touch screen is selected, the stereoscopic object movie of the selected artifact will be synchronously shown in the stereoscopic display, which can provide the user a better experience in browsing 3D artifact.
Transportation Research Part E: Logistics and Transportation Review, 2010
In this study, a mathematical model that integrates spatial and temporal dimensions is developed ... more In this study, a mathematical model that integrates spatial and temporal dimensions is developed for strategic planning of future bioethanol supply chain systems. The planning objective is to minimize the cost of the entire supply chain of biofuel from biowaste feedstock fields to end users over the entire planning horizon, simultaneously satisfying demand, resource, and technology constraints. This model is used to evaluate the economic potential and infrastructure requirements for bioethanol production from eight waste biomass resources in California as a case study. It is found that, through careful supply chain design, biowaste-based ethanol production can be sustained at a compatible cost around $1.1 per gallon.
Polymer Journal, 2008
New alternating copolymers of poly(2,7-(9,9 0 -dihexylfluorene)-alt-3,9-(5,11-di(2-ethylhexyl)-in... more New alternating copolymers of poly(2,7-(9,9 0 -dihexylfluorene)-alt-3,9-(5,11-di(2-ethylhexyl)-indolo[3,2-b]carbazole)) (PFp-In) and poly(2,7-(9,9 0 -dihexylfluorene)-alt-2,8-(5,11-di(2-ethylhexyl)-indolo[3,2-b]carbazole)) (PF-m-In) were synthesized by palladium-catalyzed Suzuki coupling polymerization and characterized for the applications of light-emitting diodes and field effect transistors (FET). The incorporation of indolocarbazole into polyfluorene could not only enhance hole transporting properties but also thermal properties. The para-linkage, PF-p-In, facilitates -electron delocalization and thus has a lower optical band gap and a higher emission maximum than those of the meta linkage, PF-m-In. The electroluminescence devices based on PF-p-In and PF-m-In as the emissive layer show a similar maximum luminance but with different emissive colors of green and blue, respectively. The FET hole mobilities of PF-p-In and PF-m-In are 6:73 Â 10 À5 and 1:50 Â 10 À4 cm 2 /VÁs, respectively, which are significantly higher than that of polyfluorene. The present study demonstrates the electronic and optoelectronic properties of polyfluorene enhanced by incorporating hole transporting indolocarbazole with different linkages.
Journal of Polymer Science Part A: Polymer Chemistry, 2004
Two new diamines, 2,4-diaminotriphenylamine (3) and N-(2,4-diaminophenyl)carbazole (4), were synt... more Two new diamines, 2,4-diaminotriphenylamine (3) and N-(2,4-diaminophenyl)carbazole (4), were synthesized via the cesium fluoride-mediated aromatic substitution reactions of 1-fluoro-2,4-dinitrobenzene with diphenylamine and carbazole, followed by palladium-catalyzed hydrazine reduction. Amorphous and soluble aramids having pendent diphenylamino and carbazolyl groups were prepared by the phosphorylation polycondensation of aromatic dicarboxylic acids with diamines 3 and 4, respectively. The aramids derived from diamine 3 had sufficiently high molecular weights to permit the casting of flexible and tough films. They exhibited excellent mechanical properties and moderately high softening temperatures in the 221-298°C range. However, the reactions of diamine 4 with aromatic diacids gave relatively lower molecular weights products that could not afford flexible films. For a comparative purpose, the parent aramids derived from m-phenylenediamine and aromatic diacids were also prepared and characterized.
International Journal of Hydrogen Energy, 2008
Optimization is applied to identify the least-cost sequence of hydrogen infrastructure build-up i... more Optimization is applied to identify the least-cost sequence of hydrogen infrastructure build-up in Southern California during 2010-2060. Given an exogenous demand, the model generates temporal and spatial decisions for building a hydrogen infrastructure, in terms of when, where, at what sizes and by what technologies, that minimize the net present value of technology, environment, and fuel accessibility costs. The least-cost sequence is then analyzed with respect to technology deployment, delivered hydrogen cost, capital requirements, subsidy need, subsidy capacity, and CO2 mitigation.
International Journal of Hydrogen Energy, 2008
The problem of hydrogen station location is often studied through understanding refueling behavio... more The problem of hydrogen station location is often studied through understanding refueling behavior or reviewing the experience of gasoline stations. Driven by the notion "where you drive more is where you more likely need refueling", this paper develops a new approach where station siting is treated as a fuel-travel-back problem and the only required data is VMT distribution. Such a fueltravel-back problem is a typical transportation problem and is solved as mix-integerprogramming model. When the total fuel-travel-back time is minimized, so is the average refueling travel time of a random motorist, for which theoretical deduction is provided. The model is applied to derive an optimal station roll-out scheme for Southern California. The results show that, if station size constraints are relaxed, only 18% of existing gas station number is needed to achieve the current fuel accessibility of gasoline in the region. Fewer stations lead to larger station size, suggesting a need to re-examine the current speculation on designs of hydrogen station and distribution system and to conduct more regional studies for discovery of optimistic and pessimistic regions for hydrogen. The results also indicate that early stations should be located strategically and even at low-demand locations, which is contradictory to existing proposition.
International Journal of Business Information Systems, 2011
ABSTRACT
Fuel, 2008
The purpose of this study was to investigate the dependence of mercury emissions on coal ranks an... more The purpose of this study was to investigate the dependence of mercury emissions on coal ranks and electric utility boilers equipped with Fabric Filter Baghouses (FF). A comparison of mercury emission rates and fly ash properties was made between a circulating Fluidized ...
Environmental Science & Technology, 2010
The formation of sulfur trioxide (SO 3 ) in coal-fired utility boilers can have negative effects ... more The formation of sulfur trioxide (SO 3 ) in coal-fired utility boilers can have negative effects on boiler performance and operation, such as fouling and corrosion of equipment, efficiency loss in the air preheater (APH), increase in stack opacity, and the formation of PM 2.5 . Sulfur trioxide can also compete with mercury when bonding with injected activated carbons. Tests in a lab-scale reactor confirmed there are major interferences between fly ash and SO 3 during SO 3 sampling. A modified SO 3 procedure to maximize the elimination of measurement biases, based on the inertial-filter-sampling and the selective-condensation-collecting of SO 3 , was applied in SO 3 tests in three full-scale utility boilers. For the two units burning bituminous coal, SO 3 levels starting at 20 to 25 ppmv at the inlet to the selective catalytic reduction (SCR), increased slightly across the SCR, owing to catalytic conversion of SO 2 to SO 3, and then declined in other air pollutant control device (APCD) modules downstream to approximately 5 ppmv and 15 ppmv at the two sites, respectively. In the unit burning sub-bituminous coal, the much lower initial concentration of SO 3 estimated to be approximately 1.5 ppmv at the inlet to the SCR was reduced to about 0.8 ppmv across the SCR and to about 0.3 ppmv at the exit of the wet flue gas desulfurization (WFGD). The SO 3 removal efficiency across the WFGD scrubbers at the three sites was generally 35% or less. Reductions in SO 3 across either the APH or the dry electrostatic precipitator (ESP) in units burning high-sulfur bituminous coal were attributed to operating temperatures being below the dew point of SO 3 .
Energy & Fuels, 2009
A systematic investigation of sorbent-trap sampling, which is a method that uses paired sorbent t... more A systematic investigation of sorbent-trap sampling, which is a method that uses paired sorbent traps to measure total vapor phase mercury (Hg), was carried out at two coal-fired power plants. The objective of the study was to evaluate the effects (if any) on data quality when the following aspects of the sorbent trap method are varied: (a) sorbent trap configuration; (b) sampling time; and (c) analytical technique. Also, the performance of a speciating sorbent trap (i.e., a trap capable of separating elemental Hg from oxidized Hg), developed by the Western Kentucky University's Institute for Combustion Science and Environmental Technology (ICSET), was evaluated by direct comparison against the Ontario Hydro (OH) reference method. Flue gas samples were taken using both "regular" and modified sorbent trap measurement systems. The regular sorbent trap systems used a dual-trap, in-stack sampling technique. The modified systems were equipped with either inertial or cyclone probes and used paired, out-of-stack sorbent traps. Both short-term (1.5 h) and long-term (18 h to 10 days) samples were collected. The OH method was run concurrently during the short-term test runs, to provide reference Hg concentrations. At one facility, mercury concentration data from continuous emission monitoring systems were also recorded during the sorbent trap sampling runs. After sampling, the conventional (nonspeciating) sorbent traps were analyzed for Hg, using either a direct combustion method or a wet-chemistry analytical method (i.e., microwaveassisted digestion coupled with cold vapor atomic absorption spectroscopy). The speciating traps were analyzed only by the direct combustion method. All of the sorbent trap data collected in the study were evaluated with respect to relative accuracy, relative deviation of paired traps, and mercury breakthrough. The in-stack and out-of-stack sampling methods produced satisfactory relative accuracy results for both the short-term and long-term testing. For the short-term tests, the in-stack sampling results compared more favorably to the OH method than did the out-of-stack results. The relative deviation between the paired traps was considerably higher for the short-term out-of-stack tests than for the long-term tests. A one-way analysis of variance (ANOVA), showed a statistically significant difference (p < 0.1) between the direct combustion and wet-chemistry analytical methods used in the study; the results from the direct combustion method were consistently higher than the wet-chemistry results. The evaluation of the speciating mercury sorbent trap demonstrated that the trap is capable of providing reasonably accurate total mercury concentrations and speciation data that are somewhat comparable to data obtained with the OH method. Although the results of the study were informative and promising, further evaluation of both the out-of-stack sampling methods and the speciating sorbent trap is recommended.
Energy & Fuels, 2007
An investigation of speciated mercury transformation with the addition of hydrogen bromide (HBr) ... more An investigation of speciated mercury transformation with the addition of hydrogen bromide (HBr) at elevated temperatures was conducted in a slipstream reactor with real flue gas atmospheres. A real flue gas atmosphere is composed of bituminous coal (with high sulfur ...
Energy & Fuels, 2008
Six mercury continuous emission monitoring (CEM) systems provided by two leading mercury (Hg) CEM... more Six mercury continuous emission monitoring (CEM) systems provided by two leading mercury (Hg) CEM system manufacturers were tested at five coal combustion utilities. The linearity, response time, day-to-day stability, efficiency of the Hg speciation modules, and ...
Chemical Engineering Journal, 2010
o-Toluidine is used primarily in the manufacture of dyestuffs, and also in the production of rubb... more o-Toluidine is used primarily in the manufacture of dyestuffs, and also in the production of rubber, chemicals, and pesticides and as a curing agent for epoxy resin systems. It is considered to be toxic and carcinogenic. This study uses the Box-Behnken statistical experiment design to investigate the degradation of o-toluidine by the photo-Fenton process. The effects of ferrous ion dosage, hydrogen peroxide concentration and UVA irradiation were selected as factors in the Box-Behnken design experiment, while, o-toluidine and COD removal efficiency were considered as response functions. Results show that ferrous ion and hydrogen peroxide concentrations were the main parameters affecting the o-toluidine and COD removal, while the number of UVA lamps had a slight effect on the reaction. From the Box-Behnken statistical design prediction, the optimum condition for removing 100% of o-toluidine and 74% of COD was 1.2 mM of ferrous ion, 8 mM of hydrogen peroxide and UVA 85.7 W/m 3 at pH 3.
Analytica Chimica Acta, 2010
Coal and fly ash contain many elements. These elements exist in different forms which may change ... more Coal and fly ash contain many elements. These elements exist in different forms which may change throughout the coal combustion process. There are several processes, including X-ray techniques and leaching techniques by which studies have attempted to assess the form of a particular element in a sample. This work focuses on determining the leachability of selected elements sequentially leached in four extraction solutions: water, 1M ammonium acetate, 3M hydrochloric acid and 50% hydrofluoric acid. The emphasis is on evaluating the steps involved in the leaching process with the mass recovery for each element being the basis for evaluation. The total amount of each element that will leach out under the given extraction condition is presented as a fraction of the total present in the material. The materials evaluated were NIST coal and fly ash standards. The elements measured in this study include aluminum, barium, beryllium, calcium, chromium, cobalt, iron, magnesium, manganese, nickel, potassium, sodium, strontium, vanadium and zinc.