NUMERICAL SIMULATION ON EMERGENCY TUNNEL FIRES WITH TRANSVERSE VENTILATION

ＮＯＭＥＮＣＬＡＴＵＲＥＣｓ：ＳｍａｇｏｒｉｎｓｋｙｃｏｎｓｔａｎｔＣｖ，Ｃｐ：Ｓｐｅｃｉｆｉｃｈｅａｔａｔｃｏｎｓｔａｎｔｖｏｌｕｍｅａｎｄｐｒｅｓｓｕｒｅ，ｒｅｓｐｅｃｔｉｖｅｌｙ，（Ｊ／ｋｇＫ）ｇ：Ｇｒａｖｉｔｙａｃｃｅｌｅｒａｔｉｏｎｖｅｃｔｏｒ，（ｍ／ｓ２）ｈｗ：Ｏｖｅｒａｌｌｃｏｅｆｆｉｃｉｅｎｔｏｆｈｅａｔｔｒａｎｓｆｅｒｏｆｔｕｎｎｅｌｗａｌｌ，（Ｗ／ｍ２Ｋ）Ｐ：Ｐｒｅｓｓｕｒｅ，（Ｐａ）Ｐ０：Ａｔｍｏｓｐｈｅｒｉｃａｂｖｏｌｕｔｅｐｒｅｓｓｕｒｅ，（Ｐａ）ｐ：Ｍｏｔｉｖｅｐｒｅ…     

Studies on the molecular weight dependence of tacticity of anionically prepared PMMAs by on-line GPC/NMR

Summary Several PMMA samples prepared in toluene with anionic initiators such as t-C₄H₉MgBr, n-C₄H₉MgCl, 1,1-diphenylhexyllithium, t-C₄H₉Li and t-C₄H₉Li(n–C₄H₉)₃Al complex were analyzed by the on-line GPC/NMR method using a 500 MHz ¹H NMR spectrometer as a real-time detector of GPC. The molecular method for a short time (60 min per sample) with a small amount of the sample (1 mg). The plots of intensities of the -methyl proton resonances due to mm- and rr-triads against elution time showed the variation of tacticity with molecular weight of the PMMA. On the basis of the results, the natures of active species in the polymerizations were discussed.     

Improved Methods for the Fatty Acid Analysis of Blood Lipid Classes

Two improved methods have been developed for preparation of fatty acid methyl esters (FAME) from major O-ester lipid classes in blood, i.e., cholesterol ester, triacylglycerol, and glycerophospholipids. The methods involve simple operations, and use neither harmful solvents such as chloroform or benzene nor highly reactive volatile reagents such as acetyl chloride. The FAME synthesis reaction proceeds under mild temperature conditions. The methods include (1) extraction of lipids from 0.2 ml of blood with 0.2 ml of tert-butyl methyl ether and 0.1 ml of methanol, (2) separation of the total lipids into lipid classes using a solid-phase extraction column or thin-layer chromatography, and (3) methanolysis of each lipid class at room temperature or at 45 °C. In all the operations, solvent concentration is performed only once prior to gas–liquid chromatography (GC). No noticeable differences in composition determined by GC have been found between FAME prepared by the present methods and those prepared by a conventional method involving lipid extraction with chloroform/methanol. The mild reaction and simplified procedures of the present methods enabled safe and reproducible analysis of the fatty acid compositions of the major ester-lipid classes in blood.     

The role of T lymphocytes in patients with food-sensitive atopic dermatitis

The role of T lymphocytes was assessed in patients with food-sensitive atopic dermatitis (AD). T lymphocytes plus monocytes responded well to ovalbumin or bovine serum albumin (BSA) in children with AD who were sensitive to hen's egg or cow's milk compared with healthy children and children with immediate allergic symptoms who are sensitive to hen's egg or cow's milk. The responding cells were shown to be predominantly CD4+ T lymphocytes. Interleukin-2 activity and interferon-gamma concentrations in culture supernatants of ovalbumin-stimulated peripheral blood mononuclear cells (PBMCs) from patients with AD who were sensitive to hen's egg were significantly higher than those of healthy children and patients sensitive to hen's egg with immediate symptoms. Expression of Fc epsilon R II on B lymphocytes in cultures of ovalbumin-stimulated PBMCs from patients with AD was significantly higher than that of healthy children, but it tended to be lower than that of patients with immediate symptoms. These results suggest that, in patients with AD who are food sensitive, CD4+ T lymphocytes stimulated by food antigens secrete lymphokines such as interleukin-2 and interferon-gamma that are secreted from TH1 clones in mice, and express Fc epsilon R II on B lymphocyte that is induced by interleukin-4 secreted from TH2 clones in mice. Taken together, cell-mediated immunity may also occur in addition to IgE-mediated hypersensitivity in patients with food-sensitive AD.     

A parallel processing simulator for a network system using multimicroprocessors

A parallel processing simulator, NEWTS, has been developed for network systems. This simulator consists of a number of microprocessors, which are interconnected with one another by hierarchical common buses and which excute simulation programs concurrently. This simulator is far cheaper than a general-purpose large computer and enables carrying out efficient and high speed network simulations. This simulator has been applied to a telephone network model, and it's usefulness confirmed. This paper describes an outline of the NEWTS hardware and software.     

Strength of natural soil flocs

To obtain the strength of flocs against breakup is crucial for controlling flocculation in water treatment and predicting transport of colloidal particles in aqueous environments. Recently, the author reported a method to obtain floc strength from a simple experiment of floc breakup subjected to a laminar converging flow. In this study, this method was applied to natural soil flocs. The flocs were formed by coagulation with 0.5 M NaCl (pH 5.4-5.5, pH 6.6) solutions, 0.1M CaCl2 (pH 6.4-6.9) solutions, or acidified distilled water with dilute HCl (pH 5.6). Obtained floc strengths were 0.3, 0.7 and 4 nN for Na-, Ca-, and H-coagulated flocs, respectively. Also, floc strength did not change with floc size. These values of floc strengths were 1-3 orders smaller than those of flocs formed with polymer flocculants and/or precipitated ferric or aluminum coagulants.     

Highly syndiotactic poly(methyl methacrylate) with narrow molecular weight distribution formed by tert-butyllithium-trialkylaluminium in toluene

Summary Polymerization of MMA with t-C₄H₉Li in toluene in the presence of trialkylaluminum(alkyl=methyl, ethyl, butyl, isobutyl, and octyl) was examined at various Al/Li ratios. Triethyl-, tributyl and trioctylaluminums worked quite effectively in the polymerization to give highly syndiotactic PMMA with narrow molecular weight distribution (MWD) at the Al/Li ratio of 3 and higher than 3. The highest syndiotacticity of 96% was attained with t-C₄H₉Li/(n-C₈H₁₇)₃Al (1/3) at –93°C. The polymerization was initiated by t-C₄H₉ anion and proceeded in a living manner. The structure of the syndiotactic PMMA is chemically identical to that of isotactic PMMA prepared with t-C₄H₉MgBr. Consequently, highly isotactic and syndiotactic PMMAs with narrow MWD and with the same chemical structure from -end to -end were obtained.     

Separation of poly(methyl methacrylate)s according to their tacticity

Summary The unconventional liquid chromatography of polymers under limiting conditions of their solubility was applied to poly(methyl methacrylate)s differing in their tacticity. The polymers were dissolved in thermodynamically good solvents and injected into an appropriate size exclusion chromatographic (SEC) column flushed with matched, moderately strong nonsolvents. The set of (limiting) conditions was found under which less soluble syndiotactic poly(methyl, methacrylate) moved along the column together with the zone of its initial solvent while better soluble isotactic poly(methyl methacrylate) was eluted according to the SEC mechanism. This indicates the potential of liquid chromatography under limiting conditions to characterize the tacticity of poly(methyl methacrylate)s.