The Chinese steel industry

The Chinese steel industry achieved even growth in the 1980s and China is now the world's fourth largest steel producing country. Two factors that have played important roles in this development of the Chinese steel industry are the reform of the system or the strengthening of enterprise autonomy accompanying market reform, and the introduction of advanced technology from Western countries as a continuing policy since the 1970s. The Chinese steel industry still lags far behind those of other steel producing countries in terms of equipment and production technology, however. The present situation and problems of the Chinese steel industry in the 1990s are discussed here, together with a review of its development in the 1980s.     

Modeling changes in paddy rice sown areas in Asia

Paddy rice fields in Asia account for over 90% of global total rice cultivation area, and the major rice-producing countries of Asia account for over one-half of the world’s population. Monitoring and understanding the dynamic changes in paddy rice agriculture in Asia are very important for agricultural sustainability, food and water security, and greenhouse gas emissions. This paper presents a crop choice decision model that dynamically simulates future changes in sown areas of paddy rice in Asia. This model was developed under the framework of Action-in-Context (AiC) with the aim of understanding land users’ decisions on crop choices among a set of available alternatives using a crop utility function. Empirical validation for the model conducted after model construction indicated the reliability of the model for addressing the complexity of current agricultural land-use change and its capacity for investigating long-term scenarios in the future. Finally, the model was applied for future scenario analysis over a time frame of 30 years with 5-year increments, beginning from the year 2005. The simulation results provided insights into rates and trajectories of changes in Asian rice areas over the test period, with the resulting implications for future agricultural sustainability in Asia. These outcomes can improve understanding of projected land-use changes and explain their causes, locations and consequences, as well as providing support for land-use planning and policy making.     

Improving the quality of waste-derived char by removing ash

This study characterized and removed ash from waste-derived char to improve the quality of char as fuel. Municipal solid waste (MSW) and automobile shredder residue (ASR) were carbonized at 450 degrees C and at 500 degrees C, respectively, in a rotary kiln with a nitrogen atmosphere for 1h. MSW and ASR char were subjected to sieving and pulverization-sieving to screen incombustibles and the ash-rich fraction, after which float-sink separation, froth floatation, and oil agglomeration were applied to remove ash from the char. The established target quality was (1) less than 30% ash content and (2) more than 20,000 kJ/kg heating value. However, the rate of combustibles recovery had to be lowered to produce a good quality of char along with a high heating value. MSW char attained the targeted quality level using froth floatation or oil agglomeration, whereas, neither separation method was able to make ASR-derived char satisfy the target. Based on the assumption that particle properties of char are determined by the weight ratio of combustibles and ash, the densities of combustibles and ash in char were estimated using the results of float-sink separation, X-ray diffraction (XRD) analysis, and elemental content. To verify the above assumption, an energy dispersive X-ray/scanning electron microscope (EDX/SEM) analyzer was used to observe char particles.     

Study of Asian Dust Phenomena in 2001–2003 Using A Network of Continuously Operated Polarization Lidars

We have conducted dust observations at a number of locations including Beijing, Hefei, Suwon, Fukue, Nagasaki, Tsukuba, and Sapporo using automated two-wavelength polarization lidars o study Asian dust phenomena, including generation, transport, and change during transport. We developed a method using the depolarization ratio for estimating the contributions of Asian dust and spherical air-pollution aerosols in observed aerosol mixtures. We analyzed the dust profiles statistically to derive climatological characteristics and year-on-year variations. We also studied dust source and transport path for each dust event using the regional chemical transport model CFORS. The statistical analysis clearly demonstrated the year-on-year variation of dust phenomena and the characteristics depending on the locations of the observational sites. Most major dust events in 2001 and 2002 originated in Inner Mongolia and/or Mongolia at the southern edge of a low-pressure area located in Siberia and were transported by strong westerlies. In 2003, the typical meteorological pattern for heavy dust cases accompanying a strong low in Siberia was not seen, except for one case in April. Furthermore, the lidar observation in Beijing suggests that less dust was generated in the source regions in Inner Mongolia and/or Mongolia, probably due to higher precipitation in 2003.     

Aerosol concentrations observed at Mt. Haruna,Japan, in relation to long-range transport of Asian mineral dust aerosols

As a part of the effort to understand the structure of long-range transported aerosol plumes and local pollution, aerosol observations monitored the mass concentrations and number-size distributions during the period August 2006 to July 2009 near the top of Mt. Haruna (1365 m), an isolated mountain in the Kanto Plain in Japan. The mass concentrations observed at Mt. Haruna and plain sites showed a seasonal variation with a maximum in spring and summer, respectively. The spring peaks in aerosols at Mt. Haruna were probably caused by long-range transport of mineral dust and anthropogenic particles from the Asian continent. The summer peaks at the plain sites was attributed to local pollution from the Tokyo metropolitan area. Three examples of 2007 Asian dust events were investigated to show that aerosols may be dispersed in a complicated three-dimensional structure and that delayed arrivals of the dust plumes at plain sites compared to Mt. Haruna were not a rare case. Because of the boundary layer being stable at night, the dust layer was advected eastward without the vertical mixing before sunrise. This study suggests that after thermal convection activated by sunlight during daytime Asian dust transported in the free troposphere may be brought down into the atmospheric boundary layer, increasing the dust concentration there.     

A model for the larval migration of the Japanese eel: roles of the trade winds and salinity front

A model that helps explain the mysterious long-distance migration of the Japanese eel (Anguilla japonica) is presented, based on oceanographic observations, satellite buoy drift experiments, and samplings of eel larvae taken in 1991. The trajectory of a 150 m depth buoy relased in the spawning area strongly suggests that A. japonica larvae spawned just south of the salinity front are transported westward by the North Equatorial Current (NEC). The larvae are then thought to be entrained into the Mindanao Current flowing southward along the Philippine Islands where A. japonica juveniles are scarcely distributed. These controversial results lead to the assumption that eel larvae are transferred from the NEC to the northward flowing Kuroshio, which distributes the eel larvae to the growth habitats of eastern Asia. In this eel larvae transfer model, a northward Ekman transport caused by trade winds plays an important role in explaining the wind-induced northward shift of the larvae together with the onset of diel vertical migration. Assuming that leptocephali greater than 20 mm initiate the vertical migration, a westward wind velocity greater than 5 to 10 m s^-1 should be high enough to diminish the southward current velocity. When the physical and geophysical conditions — such as the salinity front for spawning activity, the water tunnel for westward larval transport, the Ekman transport by the trade wind for transfer of the larvae from the NEC to the Kuroshio, and the strong velocity of the Kuroshio for rapid transport to growth habitats — are well matched with the timing of the onset of vertical migration, large-scale eel migration could result.     

Possible change in Asian dust source suggested by atmospheric anthropogenic radionuclides during the 2000s

Decades-long monitoring of anthropogenic radionuclides in the atmospheric deposition in Tsukuba, Japan suggests not only the substantial impacts of the Asian dust (Kosa) on the deposition but also the possible change of the Kosa source region, especially during springs of the 2000s. In order to know more about such change, 4 single wet deposition events occurred in the spring of 2007 were scrutinized. The largest anthropogenic radionuclides wet deposition was supplied by the April 2–4 event. It brought several tens % of the monthly depositions (April 2007) of the dust (residue) mass (4.5 g m^?2) and anthropogenic radionulides (⁹⁰Sr: 16, ¹³⁷Cs: 97 and Pu: 3 mBq m^?2). None of the events observed fulfilled both criteria of the specific activities and ⁹⁰Sr/¹³⁷Cs activity ratio to the Tsukuba soil; they did not exhibit local soil dust signature. The Kosa events in fact have extensive impacts on the atmospheric environment over Japan in spring season. Considering the elevated specific activities as well as greater ¹³⁷Cs/⁹⁰Sr activity ratio in the deposited dust, it is hypothesized that the dust source areas in Asian continent would be shifting from the arid zone to the desert-steppe zone suffering from desertification during the 2000s. This type of the Kosa may be called as the ‘new-regime Kosa’. Chemical observation in the far downwind region of the Kosa dust could allow us to know possible shift in the source regions.