Direct methanol fuel cell bubble removal mechanism using magnetic actuation

This article develops a direct methanol fuel cell (DMFC) with a magnet-actuated bubble removal mechanism. A micro-DC motor is used to control the bubble removal mechanism. The lower magnetic device is operated to extrude a Polydimethylsiloxane (PDMS) runner to compress the liquid fuel in the anode flow channel, forcing the CO₂ bubbles in the runner to flow toward the outlet end. The bubble retention in the anode flow channel is thereby improved, enhancing the cell performance. The proposed mechanism stability and performance and Polymethylmethacrylate (PMMA) runner are also discussed.     

Plasma versus Thermal Effects in Flue Gas NOx Reduction Using Ammonia Radical Injection

Abstract

A plasma-assisted ammonia injection technique was previously demonstrated as having the potential to remove NO_x from combustion flue gases at SCR-comparable levels without the use of catalysts. However, these demonstrations did not prove the advantage of plasma assistance because they did not explicitly account for enhanced radical production by bulk thermal heating. An experiment using hot ammonia injection was performed to separate this thermal effect from the effect of radical production via interaction with a plasma. Under excess air conditions, results show that a thermal effect does provide improved NO_x reduction, but not to the level achieved with the use of a plasma source. However, heating the injection gases provides only a minor improvement in NO_x reduction at NH₃/NO_x ratios and temperatures typical of commercial cold SNCR applications. The plasma effect in ammonia radical injection was also found to be significant, accounting for an additional 15% to 35% of absolute NO_x reduction beyond any thermal benefit at typical excess air conditions. The ammonia radical injection technique continues to show promise as an effective NO_x reduction alternative.     

Environmental performance evaluation and strategy management using balanced scorecard

Recently, environmental protection and regulations such as WEEE, ELV, and RoHS are rapidly emerging as an important issue for business to consider. The trend of swinging from end-of-pipe control to product design, green innovation, and even the establishment of image or brand has affected corporations in almost every corner in the world, and enlarged to the all modern global production network. Corporations must take proactive environmental strategies to response the challenges. This study adopts balanced scorecard structure and aim at automobile industries to understand the relationships of internal and external, financial and non-financial, and outcome and driving factors. Further relying on these relationships to draw the “map of environment strategy” to probe and understand the feasibility of environmental performance evaluation and environmental strategy control.     

Real-time discharge measurement in tidal streams by an index velocity

Discharge measurement in a tidal stream is always a difficult task. Owing to the complex flow conditions, discharge measurement in tidal streams has to be finished quickly, and must be highly efficient in order to yield an accurate measurement of real-time discharge. Measuring the discharge of tidal streams is done in three steps: (1) establishing the stage and cross-sectional area relation, (2) estimating the index velocity by using a velocity distribution equation based on the probability concept, (3) establishing the relationship between the index and mean velocities. Then the cross-sectional area and mean velocity can be estimated by the gage height and index velocity, respectively. The discharge of tidal streams is computed as the product of the cross-sectional area and mean velocity. The velocity distribution of the Taipei Bridge and Guan-du Bridge in the Tanshui River were established and analyzed to demonstrate the use of discharge measurement by index velocity for estimating the discharge of this tidal stream. The results reveal no large difference between the discharges measured by the conventional methods and the index velocity. This pilot study proposed a cost-effectiveness and efficient method. It is an easy, quick, and accurate model for measuring the real-time discharge of a tidal stream. It makes automatic, real-time, and continuous monitoring of the discharge in a tidal stream become possible.     

Molecular detection and comparison of Acanthamoeba genotypes in different functions of watersheds in Taiwan

The protistan genus Acanthamoeba is a free-living amoeba existing in various environments. Within this protistan genus, there are some species recognized as potential human pathogens, which may cause granulomatous amoebic encephalitis, Acanthamoeba keratitis and chronic granulomatous lesions of the skin. In this study, 211 water samples were collected from two watersheds in southern Taiwan. We detected Acanthamoeba based on the PCR amplification with a genus-specific primer pair and investigation of Acanthamoeba in Puzih River and Kaoping River in southern Taiwan. Acanthamoeba species were detected in 34 (16.1%) samples. The presence or absence of Acanthamoeba within the water samples showed significant difference with the levels of water temperature and total coliforms. The most frequently identified Acanthamoeba genotype was T4 (n = 19), followed by T5 (n = 8), and then T15 (n = 3). Genotype T6, T7/T8, T11 and T12 were all detected once. Genotype T4, T5, T6, T11 and T15 of Acanthamoeba are responsible for Acanthamoeba keratitis and should be considered a potential health threat associated with human activities in environmental surface water watersheds.     

Particle release transport in Danshuei River estuarine system and adjacent coastal ocean: a modeling assessment

A three-dimensional hydrodynamic model was created to study the Danshuei River estuarine system and adjacent coastal ocean in Taiwan. The model was verified using measurements of the time-series water surface elevation, tidal current, and salinity from 1999. We conclude that our model is consistent with these observations. Our particle-tracking model was also used to explore the transport of particles released from the Hsin-Hai Bridge, an area that is heavily polluted. The results suggest that it takes a much longer time for the estuary to be flushed out under low freshwater discharge conditions than with high freshwater discharge. We conclude that the northeast and southwest winds minimally impact particle dispersion in the estuary. The particles fail to settle to the bottom in the absence of density-induced circulation. Our model was also used to simulate the ocean outfall at the Bali. Our experimental results suggest that the tidal current dominates the particle trajectories and influences the transport properties in the absence of a wind stress condition. The particles tend to move northeast or southwest along the coast when northeast or southwest winds prevail. Our data suggest that wind-driven currents and tidal currents play important roles in water movement as linked with ocean outfall in the context of the Danshuei River.     

Performance measurement for incineration plants using multi-activity network data envelopment analysis: The case of Taiwan

This study proposes the use of multi-activity network data envelopment analysis to appraise how incineration plants in Taiwan perform. Sample data from 2006 is used to examine the trade-offs between efficiency enhancement and pollution abatement. The respective efficiencies of the waste treatment and electricity generation are also assessed in a unified framework. The empirical results indicate that it is more important to improve the efficiency of waste treatment activity than of electricity generation activity in order to enhance the overall performance of Taiwan's incinerators. Since ownership, location and length of operations do not in general affect their performance, any improvement has to come from the careful monitoring of each process of the waste treatment operations. Furthermore, given that the policy in Taiwan has moved away from incineration to recycling, the problem of an over-supply of incinerators may become apparent in the near future. Our results indicate that the availability of capacity size may be an important factor when policy-makers consider whether to close down some existing incinerators.     

A storm event-based approach to TMDL development

It is vitally important to define the critical condition for a receiving water body in the total maximum daily load (TMDL) development process. One of the major disadvantages of using a continuous simulation approach is that there is no guarantee that the most critical condition will be covered within the subjectively selected representative hydrologic period, which is usually several years depending on the availability of data. Another limitation of the continuous simulation approach, compared to a design storm approach, is the lack of an estimate of the risk involved. Because of the above limitations, a storm event-based critical flow-storm (CFS) approach was previously developed to explicitly address the critical condition as a combination of a prescribed stream flow and a storm event of certain magnitude, both having a certain frequency of occurrence and when combined, would create a critical condition. The CFS approach was tested successfully in a TMDL study for Muddy Creek in Virginia. The present paper reports results of a comparative study on the applicability of the CFS approach in Taiwan. The Dy-yu creek watershed in northern Taiwan differs significantly from Muddy Creek in terms of climate, hydrology, terrain, and other characteristics. Results show that the critical condition for different watersheds might be also different, and that the CFS approach could clearly define that critical condition and should be considered as an alternative method for TMDL development to a continuous simulation approach.     

Identification and quantitative detection of Legionella spp. in various aquatic environments by real-time PCR assay

In this study, a SYBR green quantitative real-time PCR was developed to quantify and detect the Legionella spp. in various environmental water samples. The water samples were taken from watershed, water treatment plant, and thermal spring area in Taiwan. Legionella was detected in 13.6 % (24/176), and the detection rate for river water, raw drinking water, and thermal spring water was 10, 21.4, and 16.6 %, respectively. Using real-time PCR, concentration of Legionella spp. in detected samples ranged between 9.75?×?10⁴ and 3.47?×?10⁵?cells/L in river water, 6.92?×?10⁴ and 4.29?×?10⁵?cells/L in raw drinking water, and 5.71?×?10⁴ and 2.12?×?10⁶?cells/L for thermal spring water samples. The identified species included Legionella pneumophila (20.8 %), Legionella jordanis (4.2 %), Legionella nautarum (4.2 %), Legionella sp. (4.2 %), and uncultured Legionella sp. (66.6 %). The presence of L. pneumophila in aquatic environments suggested a potential public health threat that must be further examined.