Gas screening effect caused by steam curtains

Steam curtain equipment is used to prevent leaking flammable gases from reaching ignition sources, such as furnaces. However, steam curtains are sometimes designed badly and are ineffective for preventing the leaking gas from spreading in the windward direction. The leaked gas may pass on either side of the stream curtain, it may pass between the nozzles, or it may pass on the upper side of the stream curtain. At present, data to design the best stream curtains are quite rare. It is necessary to obtain fundamental data on the entrainment of air by steam jet and on the inclination of the steam curtain caused by the strong wind. Therefore, a series of experiments to investigate the entrained air and the inclination of the steam curtain were performed, in addition to further theoretical considerations. Thus, fundamental data useful for the design of the steam curtain equipment have been obtained.     

Quantitative and structural analyses of hazardous elements in Chinese medicines and herbs

Thirty samples of Chinese medicines and herbs were analyzed using instrumental neutron activation analysis (INAA) and X-ray diffraction (XRD) methods, mainly noting on the hazardous elements arsenic (As), mercury (Hg), chromium, antimony and cobalt. The three Niuhuang Jiedu Pian samples contained 8.6%, 8.3% and 2.2% As. Two out of four Liushen Wan samples contained approximately7% of both As and Hg. Despite being identically named, the other two Liushen Wan samples did not contain such high concentrations. Japanese Liushen Wan for children contained 1.2 ± 0.03% As and 31 ± 12 mg/kg Hg, whereas Liushen Wan for adults manufactured by another Japanese company contained 550 ± 22 mg/kg As and 1.2 ± 0.05 mg/kg Hg. All the chemical structural formulas of As and Hg in the high-concentration Niuhuang Jiedu Pian and Liushen Wan were realgar (As₄S₄), uzonite (As₄S₅) and cinnabar (HgS). Although the human body is generally not believed to absorb sulphides, continuous intake of these Chinese medicines is potentially no good because it is possible that some arsenic-sulfides will dissolve in gastric acid and then alter their chemical structures. Additionally, many herbs contained low concentrations of Hg, and their chemical structures were unknown.     

Contrasting pattern of mitochondrial population diversity between an estuarine bivalve, the Kumamoto oyster Crassostrea sikamea, and the closely related Pacific oyster C. gigas

The Kumamoto oyster (Crassostrea sikamea) shows a spatially restricted distribution, favoring estuarine tideland environment. On the other hand, the Pacific oyster (C. gigas) has a broader range of habitat. The present study compared the mitochondrial population structure between the two closely related species. For accurate species identification of oysters sampled from Japanese and East Asian continental coasts, we performed sequencing analysis of the mitochondrial DNA (mtDNA) and PCR-RFLP assay of the first internal transcribed spacer of nuclear rRNA genes. Then, we estimated the extent of population differentiation within each of C. sikamea and C. gigas based on the mtDNA data. Few haplotypes were shared among the sites of sampling in C. sikamea, which contrasted with an extensive haplotype sharing among C. gigas samples. We discuss the mechanisms of elevated population differentiation observed in C. sikamea in light of the ecology and the ancient ocean geography around the present-day habitats.     

Comparison of Surface Organic Compound Mass Spectrum Patterns by LD-TOFMS for Megalopolis Atmospheric Particles and Diesel Exhaust Particles (DEP)

PM_2.5 and PM₁₀ samples for megalopolis atmospheric particles were collected at Shinjuku, Tokyo in December 1998–January 1999 and August 1999, for two weeks both in winter and summer, with a 24 hr sampling interval. Sampling of PM_2.5 and PM₁₀ in diesel exhaust particles (DEP) was carried out using an automobile exhaust testing system, with a diesel truck placed on a chassis dynamometer. Sampling conditions included idling, constant speed of 40 km hr^-1, M-15 test pattern and 60%-revolution/40%-load of maximum power. Mass spectrums of organic compounds adhering to the surface of the PM_2.5 and PM₁₀ samples were analyzed by laser desorption time-of-flight mass spectrometry (LD-TOFMS, analytical mass range: m/z 1–m/z 380 000). LD-TOFMS analysis of those samples revealed consistently the detection of low-mass organic compounds up to m/z 800. For the megalopolis atmospheric particles, the mass spectrum pattern of wintertime samples was almost the same as that of the summertime samples for both PM_2.5 and PM₁₀. The major peak was m/z 177, and the minor peaks were m/z 84, 94, 101, 163, 189 and 235. The mass spectrum pattern of DEP was the same for all samples under all test conditions. The major peak was m/z 101, and other detected peaks were small.     

Size distribution and anthropogenic sources apportionment of airborne trace metals in Kanazawa, Japan

Aerosol samples were collected from Kanazawa, Japan to examine the size distribution of 12 elements and to identify the major sources of anthropogenic elements. Key emission sources were identified and, concentrations contributed from individual sources were estimated as well. Concentrations of elements V, Ca, Cd, Fe, Ba, Mg, Mn, Pb, Sr, Zn, Co and Cu in aerosols were determined with ICP-MS. The results showed that Ca, Mg, Sr, Mn, Co and Fe were mainly associated with coarse particles (>2.1 μm), primarily from natural sources. In contrast, the elements Zn, Ba, Cd, V, Pb and Cu dominated in fine aerosol particles (<2.1 μm), implying that the anthropogenic origin is the dominant source. Results of the factor analysis on elements with high EF_Crust values (>10) showed that emissions from waste combustion in incinerators, oil combustion (involving waste oil burning and oil combustion in both incinerators and electricity generation plants), as well as coal combustion in electricity generation plants were major contributors of anthropogenic metals in the ambient atmosphere in Kanazawa. Quantitatively estimated sum of mean concentrations of anthropogenic elements from the key sources were in good agreement with the observed values. Results of this study elucidate the need for making pollution control strategy in this area.     

Deposition of 137Cs in Rokkasho, Japan and its relation to Asian dust

Biweekly atmospheric depositions of (137)Cs were measured in Rokkasho, Aomori, Japan from March 2000 to March 2006 to study recent (137)Cs deposition. Although the deposition level was generally lower than the detectable limit, deposition samples collected in spring occasionally had measurable levels of (137)Cs. The annual (137)Cs deposition from 2001 to 2005 was 0.04-0.69 Bq m(-2) with a mean value of 0.27 Bq m(-2). Depositions of insoluble Al, Fe and Ti were strongly correlated with the (137)Cs deposition, suggesting that suspension of soil particles was the main source of the recent (137)Cs deposition. Asian dust events were coincident with some of the significant (137)Cs depositions in spring. It was found that the ratios of (137)Cs/Al and Fe/Al could be used as indices for discriminating Asian dust from suspension of the local surface soil. Backward trajectory analysis suggested southern Mongolian and northeastern China regions as sources of the significant (137)Cs depositions.     

Formation of the resource concept in Japan: pre-war and post-war efforts in knowledge integration

The objective of this paper is to trace the evolution of the resource concept in modern Japan by highlighting key individuals who played major roles in communicating this idea to a wider audience during its formation and development between the 1910s and 1950s. Special attention will be paid to the effect of different historical contexts on interpretations of the term “resource”. The paper reveals how the integration of knowledge indispensable for achieving sustainability occurs. The orientation of resource policy was drastically different before and after World War II. In the pre-war period, the military government used the resource concept to create a comprehensive inventory of the nation’s military forces, and “resource” was thus a convenient term to neutralize the aggressive connotations of top-down military mobilization. After the turn to democratic principles in 1945, “resource” suddenly acquired a symbolic meaning as a means to serve the people. Despite these contrasts, however, pre and post-war resource concepts share a commonality in that the government acted as the centralizing force, providing a platform to integrate disparate knowledge under the resource concept. At a time when society itself is more prone to fragmentation, the resource concept, which played a significant role in unification in the past, should be re-examined. The history of the concept in Japan, particularly during the pre and post-war period up until the 1950s, contains a wealth of insights as to how this can be achieved.

Parker��s sneak-guard model revisited: why do reproductively parasitic males heavily invest in testes?

Alternative reproductive tactics are widespread in males and may cause intraspecific differences in testes investment. Parker's sneak-guard model predicts that sneaker males, who mate under sperm competition risk, invest in testes relatively more than bourgeois conspecifics that have lower risk. Given that sneakers are much smaller than bourgeois males, sneakers may increase testes investment to overcome their limited sperm productivity because of their small body sizes. In this study, we examined the mechanism that mediates differential testes investment across tactics in the Lake Tanganyika cichlid fish Lamprologus callipterus. In the Rumonge population of Burundi, bourgeois males are small compared with those in other populations and have a body size close to sneaky dwarf males. Therefore, if differences in relative testis investment depend on sperm competition, the rank order of relative testis investment should be dwarf males?>?bourgeois males in Rumonge?=?bourgeois males in the other populations. If differences in relative testis investment depend on body size, the rank order of relative testes investment should be dwarf males?>?bourgeois males in Rumonge?>?bourgeois males in the other populations. Comparisons of relative testis investment among the three male groups supported the role of sperm competition, as predicted by the sneak-guard model. Nevertheless, the effects of absolute body size on testes investment should be considered to understand the mechanisms underlying intraspecific variation in testes investment caused by alternative reproductive tactics.