Bottom-up approach for downscaling CO2 emissions in Taiwan: robustness analysis and policy implications

The roles and responsibilities of cities in CO₂ mitigation have drawn increasing attention in recent years. To facilitate optimal design of effective mitigation policies, it is important for city authorities to understand the magnitudes and sources of their CO₂ emissions, and their relative shares of emissions at a higher spatial level. Although several studies estimate CO₂ emissions at the city level, the robustness of these estimates and their linkage to emissions at a higher level remains unclear. This kind of localized information on emissions is important for coordination of climate policies at different spatial scales. The study aims to fill a gap in understanding by building a systematic bottom-up approach for estimating urban CO₂ emissions and offering a consistency check with IPCC top–down estimates. Using Taiwan as a case study, we display the geographic distribution of CO₂ emissions. The significance and implications of the downscaling CO₂ emissions are indicated accordingly.     

Feasibility study on high-temperature sorption of hydrogen sulfide by natural soils

In this study, seven natural soils were tested for the sorption of hydrogen sulfide from coal gasification gas at high temperature. Results indicate that the LP natural soil has the best performance and the highest sulfur sorption capacity. After extracting free iron oxides, most natural soils have no sorption efficiency. The free iron oxides, therefore, proved to be the major components that react with hydrogen sulfide to form iron sulfides. The sulfur sorption capacity, either determined by EA or breakthrough time, is very close to the theoretical value based on the stoichiometric calculation with the content of free iron oxides. Moreover, the presence of CO is a positive effect while H2 is a negative effect. This can be explained via the water-shift reaction. On the basis of the results of temperature-programmed sulfidation (TPS), the starting temperature for the sorption of hydrogen sulfide is between 623-673 K. From the analyses of temperature-programmed oxidation (TPO) and XPS, the iron polysulfides are the major products and approximately 90% regeneration efficiency can be theoretically achieved while the temperature is controlled higher than 813 K. In the regeneration tests, the results show that the LP natural soil can be regenerated and thus reused after the oxidation process. No significant degeneration occurs on the LP natural soil after five sorption/regeneration cycles. The sulfur sorption capacity of the tenth regenerated soil can be achieved at least 80% compared to the fresh one. The experimental analyzed SO2 concentration from the regeneration process is almost identical to the theoretical calculated equilibrium concentration of the process. Maghemite is the main product after the regeneration process.     

Identifying crucial safety assessment criteria for passenger ferry services

This study empirically identified crucial safety assessment criteria for enhancing ferry safety and compare difference between ferry passengers’, ferry operators’, academics’ and ferry governors’ perceptions of their level of importance in Taiwan. Exploratory factor analysis was subsequently conducted to summarize the safety assessment items into underlying dimensions. Six dimensions were identified, namely: safety equipment, ship structure, ship documentation inspection, safety instructions, navigation and communication, and crew members’ ability. Further analysis indicated that crew members’ ability was the most important dimension in the passenger ferry context, followed by safety equipment, ship structure, navigation and communication, ship documentation inspection, and safety instructions. Differences between passengers’ academics’, ferry operations’ and ferry governors’ perceptions of the level importance of the safety assessment dimensions were found. Implications of the study findings for improving the safety of passenger ferry services are discussed.     

Prenatal diagnosis of X-linked hydrocephalus in a Chinese family with four successive affected pregnancies

We report on a woman with four successive pregnancies affected with X-linked hydrocephalus (XLH). The first child had prenatal craniocentesis and died in utero. The second child had a postnatal shunting operation, but suffers from severe growth and mental retardation at 5 years of age. In the third pregnancy, prenatal ultrasound detected hydrocephalus at the 16th and 20th weeks of gestation and the pregnancy was terminated. In the fourth pregnancy, ultrasound scanning at the 17th and 20th weeks of gestation revealed no remarkable findings, but hydrocephalus was detected at the 24th week. Autopsy confirmed the prenatal diagnosis. DNA polymorphism analysis of the Bell site of exons 17–18 of factor VIII gene of the woman and her last two fetuses seemed to be compatible with a linkage between the XLH locus and factor VIII gene. Although XLH has a variable presentation of ventriculomegaly, ultrasound scanning is still a useful tool for prenatal diagnosis at present. Earlier and more accurate prenatal diagnosis will be feasible with molecular analysis of the XLH locus or its flanking regions.     

Study On the Hydraulic Characteristics of Taichung Harbour in Taiwan

For this study, field measurements of current profiles, buoy trajectories and the lag of two tidal stations were performed to explore the flow characteristics of Taichung Harbour. in order to distinguish the effects of wind drift current on circulation inside Taichung Harbour, field surveys during both summer and monsoon (winter) season were completed separately. the speed of the drift current was about 3.5% that of the, wind speed, based on the field data. the horizontal dispersion coefficients were close to Bowden's (1965) formula for the tidal current. the water temperature showed a two-layer profile, with the mixing thickness about 4 to 6 metres for the upper layer. the corresponding Richardson number was about 70. the tidal lag between the two tidal stations was 9.68 minutes. All the results agree well with the theoretical results.     

Titanium dioxide mediated photocatalytic degradation of monochlorobenzene in aqueous phase

The reaction sequence for the photocatalytic degradation of monochlorobenzene (MCB) in UV/TiO2 process, including substrate adsorption, degradation, and mineralization, was studied. The theoretical maximum quantity of MCB that could be adsorbed onto TiO2 surface in aqueous phase was 0.18+/-0.04 micromol m(-2) of TiO2. In accordance with the upper limit of the relative surface coverage of MCB molecules to surface hydroxyls of TiO2 was around 2.2%, the water molecules as the major adjacent species near TiO2 surface would compete with MCB molecules. Increasing the initial substrate concentration to an appropriate value or enhancing the affinity between the MCB and the TiO2 surface by adjusting the solution pH would promote the photocatalytic degradation. Experimental results revealed that the neutral medium was beneficial for the degradation of MCB. In comparison, the mineralization was most improved at acidic condition. Generally, 90% of the total organic carbon (TOC) was mineralized after 240 min illumination time in the examined pH range except solution pH 11. The suppressed mineralization of MCB at solution pH 11 was ascribed to the lack of adsorption. A simplified 2-step consecutive kinetic model was used to simulate the mineralization.     

Metabolic pathway of anaerobic digestion and reaction rate limiting step of 2,4,5-TCP

A study of the effluent of an anaerobic fluidized bed reactor acclimated to 2,4,5-TCP was made in order to determine the metabolic pathway and reaction rate limiting step of 2,4,5-TCP. The wastewater with about 2500 mg L⁻¹ COD and 50 mg L⁻¹ 2,4,5-TCP was biodegraded by anaerobic digestion, and the intermediate analyzed by HPLC and GC/MS. The results showed the degradative metabolic pathway of 2,4,5-TCP, under anaerobic conditions, to be: 2,4,5-TCP→3,4-DCP→3-CP→phenol→benzoate. For the rate limiting step, the accumulated concentration of 3,4-DCP was higher than other intermediates for Anaerobic Toxicity Assay (ATA) and Biochemical Methane Potential (BMP) tests. From the anaerobic fluidized bed reactor, analyses showed the chloride at the ortho-position was removed very quickly after 2,4,5-TCP entered the reactor. As for the intermediate products, 43% of 3,4-DCP was not decomposed and of the 3-CP only 6.4% left. This shows that the rate limiting step of 2,4,5-TCP was the dechlorination of 3,4-DCP.     

Epipelagic mesozooplankton succession and community structure over a marine ouffall area in the northeastern South China Sea

This study analyses distribution and abundance patterns of mesozooplankton communities at 13 stations in the coastal waters over a marine outfall area in the northeastern South China Sea. Cruises were conducted in March, June and September 2002, and plankton samples were collected with a 333 microm North Pacific net. The Mesozooplankton was dominated by calanoid Copepods, Cladocera, Chaetognatha and Pteropoda. Stations located near the entrance of the harbor provided a relatively higher abundance of Noctilucales and Radiolarians. In total, 20 zooplankton groups were identified in which, Calanoida, Cladocera, Chaetognatha, Pteropoda, Poecilostomatoida and Appendicularia comprised 92.77% of the total zooplankton abundance. Copepoda dominated in all three cruises, comprising 65.32% of the total mesozooplankton abundance. Samples collected in June recorded higher mesozooplankton abundance than March and September samples. Onshore stations recorded higher BOD values, higher abundance of Noctilucales and Radiolarians and a relativelylower abundance of the overall mesozooplankton. Total mesozooplankton abundance did not correlate significantly with temperature, pH, or dissolved oxygen, but correlated negatively with BOD.