Browsing by Author "Den, Walter"

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A study on Developing the Indicators of Energy Conservation and Carbon Reduction for the Business
(2014-01-01)
Lin, Liang-kong
;
Den, Walter
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Chou, Ying-Chyi
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Yen, Hsin-Yi
;
Lu, Ching-Hua
Green House Gas (GHG) emission has become a critical issue for firms to achieve sustainability. This paper focuses on improving enterprises allocate resource on greening more efficiently and proposes a hybrid MCDM model combining Analytic Hierarchy Process (AHP) and Decision-making Trial and Evaluation Laboratory (DEMATEL) to recognize the crucial criteria which have dependence and causality, and build the network relationship map among all GHG criteria. Eighteen criteria of GHG emission with six dimensions were selected from the literatures and modified by six experts of energy sector. The results showed that improve energy efficiency and reduce energy consumption are recognized to be the most influential dimensions of six. In addition, identifying the causality between six dimensions provide an insight for practitioners utilizing firm's resources in GHG emission more effectively.
Electrocoagulation of silica nanoparticles in wafer polishing wastewater by a multichannel flow reactor: A kinetic study
(2006-12-01)
Den, Walter
;
Huang, Chihpin
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環境工程研究所
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Institute of Environmental Engineering
A simplistic and systematic procedure has been developed for the design and upscaling of a multichannel, continuous-flow electrocoagulation reactor of monopolar configuration for the removal of submicron particles from wastewater, Using wastewater generated from the chemical-mechanical planarization process as the target wastewater, a series of laboratory-scale studies were conducted to determine the required operating conditions for the efficient removal of the ultrafine silica particles. These operating criteria included charge loading (>= 8 F/m(3)), current density (>= 5.7 A /m(2)), hydraulic retention time (>= 60 min), as well as the initial pH (7-10). Furthermore, a steady-state transport equation with second-order reaction kinetics was employed to describe the rate of coagulation as the rate-limiting factor. The actual kinetic constant determined from the laboratory-scale experiments was approximately 1.2 X 10(-21) m(3)/s, which was three orders of magnitude smaller than that calculated based on Brownian coagulation. The model was subsequently validated with a series of experiments using a pilot-scale electrocoagulation reactor geometrically similar to the laboratory-scale reactor with nearly 20 times volumetric scaleup.
Preparation of N-doped TiO2 photocatalyst by atmospheric pressure plasma process for VOCs decomposition under UV and visible light sources
(2007-06-01)
Chen, Chienchih
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Bai, Hsunling
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Chang, Sue-min
;
Chang, Chungliang
;
Den, Walter
The nitrogen doped (N-doped) titanium dioxide (TiO2) photocatalyst was prepared by the atmospheric-pressure plasma-enhanced nanoparticles synthesis (APPENS) process operated under normal temperature, i.e. the dielectric barrier discharge plasma process. The N-2 carrier gas is dissociated in the AC powered nonthermal plasma environment and subsequently doped into the TiO2 photocatalyst that was capable of being induced by visible light sources. The APPENS process for producing N-doped TiO2 showed a higher film deposition rate in the range of 60-94 nm/min while consuming less power (< 100 W) as compared to other plasma processes reported in literatures. And the photocatalytic activity of the N-doped TiO2 photocatalyst was higher than the commercial ST01 and P25 photocatalysts in terms of toluene removals in a continuous flow reactor. The XPS measurement data indicated that the active N doping states exhibited N 1s binding energies were centered at 400 and 402 eV instead of the TiN binding at 396 eV commonly observed in the literature. The light absorption in the visible light range for N-doped TiO2 was also confirmed by a clear red shift of the UV-visible spectra.
WASTEWATER TREATMENT EQUIPMENT
(2005-12-22)
Huang, Chihpin
;
Den, Walter
A wastewater treatment equipment comprising a reaction tank, a plurality of anodic plates, a plurality of cathodic plates, a power supply and a collection device is provided. The reaction tank comprises an inlet and an outlet. The anodic plates and the cathodic plates are placed in a staggered order in the reaction tank. The power supply is electrically connected to the anodic plates and the cathodic plates. The collection device is disposed at the bottom of the reaction tank so the colloidal particles deposited at he bottom of the reaction tank can be removed.