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Thermal stability of energetic materials is often screened by differential scanning calorimetry and accelerating rate calorimetry measurements. On the other hand, bond dissociation energies can explain reactivity or stability of chemical compounds. Here bond dissociation energy was derived from standard enthalpies of formation estimated by semi-empirical molecular orbital calculations using the MOPAC-PM7 package. The weakest bond dissociation energies of energetic materials and their onset temperatures in differential scanning calorimetry and accelerating rate calorimetry measurements correlated well, except for molecules where decomposition was favored by effects like intermolecular interactions. Bond dissociation energies derived from molecular orbital calculations have been found useful to roughly predict onset temperatures in the calorimetric measurements for energetic materials where data may sometimes not be available.

This study examines consensus building in environmental and energy policies by analyzing the minutes of the safety and security committee of the Nuclear Regulation Authority (NRA) of the Japanese government, in the context of the discussion of the safe return of Fukushima evacuees after the 2011 Great East Japan Earthquake and Tsunami and the subsequent Fukushima nuclear disaster. One important issue associated with evacuation policies was the high number of evacuees, if not all, who were not willing to return to their old homes. Although the contents of governmental committee meetings are freely accessible through the internet, they have been rarely analyzed for these purposes. In this study, we used text-mining techniques to analyze NRA committee minutes quantitatively and qualitatively. We have three primary findings. First, the committee attempted to take evacuees’ feelings into account and pragmatically discuss what was needed to restore their lives and livelihoods, as well as to make its meetings tr...

Biological aerosol particles are recently gaining increased attention, but global estimates of their emissions are unclear. Traditional organic tracers for biological particles have not been able to capture the diversity of biological sources such as residential wood burning. Here, we have analyzed protein content in air particulate matter over a year in a suburban area near Shibuya, in order to identify contributions from biological sources. Aerosols were separated into five size fractions using a high-volume cascade impactor. Amino acid profiles were obtained from acid hydrolysates by high-performance liquid chromatography and were subsequently used in a receptor model for source apportionment. Results show that protein content ranged from 0.5 to 2 % throughout the year in all size fractions. We observed contributions from seasonally variable emission sources such as pollen and fallen leaves in coarse particles, larger than 7 µm, at elevated concentrations during spring and winter. We also found contributions from pollen and fallen leaves in the smallest size fraction, lower than 1.1 µm, after spring. This finding indicates that sources are broken up to smaller particles in the urban environment. Overall, our findings demonstrate that protein content can be used as marker for biological aerosol particles, and that protein amino acid composition can distinguish multiple sources.

A flow-type electrochemical wastewater treatment cell that uses a natural water flow without circulation or stirring device was investigated. Aluminium pipes were used as substrates; they were coated with Sb-doped SnO2 in order to fabricate Sb-SnO2/Al electrodes, and stainless steel pipes of a different diameter were used as counter electrodes. Three types of cells were prepared, in which electrodes (anode or cathode) were placed perpendicularly; these electrode pipes were arranged in concentric circles in a container. Electrolysis was conducted using a solution containing N,N-dimethyl-p-nitrosoaniline that can selectively react with OH radicals, and the changes in concentration were measured. The concentration decreased clearly when the solution passed through the electrodes only once. It was evident that the treatment efficiency differed due to the cell design, even when the same electrode (property and area), electrolyte, current density and water volume were used. This study suggests that in order to treat wastewater efficiently, it is important to consider not only the material of the electrodes but also their shape or arrangement and the water flow in a cell.

パラフィン燃料をベース燃料とし, セタン価向上剤, 芳香族, 高沸点成分を添加した試験燃料により, セタン価および燃料性状がディーゼル排気中の有害成分, 特に粒子状物質 (PM) とPM中の多環芳香族に及ぼす影響を調べ, 有害排気成分の生成機構を考察した。ディーゼル燃焼排気中のPMに含まれるすす成分 (soot) については, セタン価の増加および芳香族成分の増加による排出量の増加が見られ, SOFに関しては高沸点成分の添加による排出増加が見られた。PM中に含まれるPAHsは, 燃料中に含まれるPAHsの未燃成分が排出する過程の寄与が大きく, PAHsの熱合成においては燃料の芳香族分の寄与が小さいことが示唆される。市販軽油を用いた実験結果もこのことを支持している。また, PAHsの熱合成は, soot の生成機構とは異なる機構で行われることが示唆される。さらに, 燃料のセタン価向上により未燃燃料由来のPAHs排出量が低減することが示された。未燃炭化水素 (THC), 一酸化炭素 (CO), 窒素酸化物 (NOx) については, 既往の研究結果とほぼ適合する結果であった。

The concentration distributions of NOx, PM, HC and CO in an urban street canyon have been estimated using a two-dimensional air quality numerical model based on the k–e turbulent model and the atmospheric convection diffusion equation when various cetane improvers were used in diesel fuels. A wind vortex can be found within the street canyon, and the pollutants emitted from the bottom of the street canyon tend to follow the course of the wind field, moving circularly. The addition of cetane improvers can improve the air quality in a street canyon, all of the pollutants were found to decrease with increasing centane number.

In order to predict the air quality impact by vehicle emissions within an urban street canyon, a two-dimensional air quality numerical model was developed based on atmospheric convection diffusion equations and a k–e turbulent model. The numerical model has been evaluated using the database from a set of street canyon air tracer experiments carried out near the crossing of Aoyama ichome, Minato-ku, Tokyo in December 1980, by the Japan Environmental Management Association of Industry (JEMAI). Twenty-four cases have been studied for the sensitivity analysis, including more practical cases when the inflow wind has an inclination with the horizontal road and the two buildings have different heights. As a result, it has been shown that the concentration distributions of pollutants emitted from the street are governed by both the inflow wind and the street canyon geometry. A stable vortex was formed within the street canyon, which agrees with other researchers. Pollutant concentrations were predicted to have higher values on the leeward side compared to the windward side. It was concluded that the released pollutants from street canyon become more diluted in the following cases: a lower height of the street canyon, a faster wind speed, a higher height of the leeward building than the windward building and an inflow wind direction towards the street. It is also suggested that the numerical model is useful for predicting the air quality within a typical urban street canyon.

To clarify the reaction mechanism in order for elucidating the effects of cetane number improving agents, we have attempted to calculate the pressure-temperature profile for the spontaneous ignition of n-butane in the presence of cetane number improving agents. First, ignition delay periods were calculated under the conditions similar to those used into the experiment using a rapid compression machine to confirm the validity of the model. Next, the effects of known cetane number improving agents such as alkyl nitrates, alkyl nitrites, and organic peroxides on ignition delay periods were examined under adiabatic conditions at constant volume. As a result, all cetane number improving agents reduced the ignition delay period of n-butane. On the other hand, nitromethane, wich has no cetane number improving effect, did not show any effect on the ignition delay period. Alkyl radicals produced from thermal decomposition of cetane number improving agents may play an important role in the reduction of the ignition delay period. The main reactions of the alkyl radicals involved in the reduction of the ignition delay period of n-butane were determined using the simple sensitivity analysis.

The reaction of apparently long-lived, oxygen-centered gas-phase free radicals, which may cause damage to a living body, from combustion smoke of poly(methyl methacrylate) with typical radical scavengers, diphenylamine and 2,6-di-t-butyl-4-methylphenol has been studied. ESR spectra of the spin adducts of gas-phase radicals were observed in the presence of both radical scavengers. Results show that gas-phase radicals in combustion smoke do not react with these radical scavengers directly, but undergo complicated reactions like induced decomposition. In the case of diphenylamine, it was observed that radical concentrations increased with exposure. It is suggested that this increase may be caused by the reaction of organic peroxides or hydroperoxides in the combustion smoke with diphenylamine.

硝酸エステルや有機過酸化物などのセタン価向上剤は熱分解で生成するラジカルがセタン価向上に関与しているこ とが知られており, ラジカル発生剤であるアゾ化合物はセタン価を向上させる効果が期待できる。そこで, アゾ化合 物のセタン価向上効果について検討した。その結果, 検討したすべてのアゾ化合物にセタン価向上効果が認められ た。また, アゾ化合物の炭素鎖や置換基の種類がセタン価向上効果に影響を及ぼすことが分かった。これらは, アゾ 化合物は熱分解によりアルキルタイプのラジカルを生成し, さらにそれから生成する種々のラジカルが燃料の前着火 段階におけるラジカル連鎖反応を促進することによりセタン価を向上するためと考えられる。

The present invention provides a differential mobility analyzer for the classification of aerosols, comprising a chamber having two generally parallel faces and means to confine gases in the chamber, one of the faces having a generally arcuate, annular sheath air channel having an axis of symmetry, other of the faces having a generally arcuate, annular aerosol channel having an axis of symmetry generally coincident with the axis of symmetry of the sheath air channel, a first one of the faces having a sample flow aperture generally aligned with the axis of symmetry of the sheath air channel, a second one of the faces having an excess flow aperture generally aligned with the axis of symmetry of the sheath air channel, and means for maintaining an electric potential difference between the faces.

We have calculated heats of formation (Δ Hf°) for nitramines and alkyl nitrates with the semi-empirical molecular orbital theory, PM3 and the molecular mechanics, MM2. Both methods can estimate Δ Hf° accurately. By combining heats of vaporization and sublimation obtained by the additivity rule with Δ Hf° in the gas phase obtained by PM3 and MM2, Δ Hf° in condensed phases can be estimated accurately enough for energy hazards prediction.

We have calculated heats of formation (Δ Hf°) for azoles with the semi-empirical molecular orbital theory, PM3. SC-DSC (sealed cell differential scanning calorimetry) measurements for some azoles h...

We have attempted to calculate heats of formation (δHf° for aliphatic nitro compounds with the semi-empirical molecular orbital theory, PM3 and the molecular mechanics, MM2'. Both methods can estimate δHf° accurately, though in case of polynitro compounds, differences between observed and calculated values become slightly larger. By combining heats of vaporization and sublimation obtained by the additivity rule with δHf° in gas phase obtained by PM3 and MM2', δHf° in condensed phase can be estimated with accuracy enough to use δHf° for energy hazards prediction.

Heats of formation (δ Hf □) for nitro compounds have been calculated with the semi-empirical molecular orbital theory and the molecular mechanics. Semi-empirical MO method PM3 and molecular mechanics MM2 can estimate δ Hf □ accurately enough for practical use. However, accurate δ Hf □ can't be calculated by MM2 for tetranitromethane which has spatially very crowded structure.

Alcohols-aldehydes-NO x -air system smog chamber experiments were undertaken and the reaction model was developed based on the experimental results. Ozone formation behaviors of alcohols and aldehydes were investigated with the computer simulation by changing the ratio of reactants. The effect of alcohol fuel on O 3 formation was estimated. Aldehydes have high reactivity in the atmospheric photochemical reaction. Alcohols can promote O 3 formation substantially under reactive conditions. The efficient control of aldehydes emissions is especially important.

In order to obtain fundamental knowledge on biological damage caused by the smoke from combustion of poly(methyl-methacrylate) (PMMA), we investigated the oxidation of cysteamine induced by PMMA smoke. We suggest that the long-lived and oxygen-centered radicals involved in PMMA smoke should play an important role in the oxidation of cysteamine. The mechanism for the oxidation of cysteamine by combustion smoke of PMMA was postulated as radical initiated chain reactions, taking into account the effect of pH, oxygen and radical concentrations.

We have attempted to examine the effects of radical scavengers, such as amines and phenols, to trap gas-phase radicals produced from the combustion of Poly (methyl methacrylate)(PMMA), which might cause damage to a living body, using an electron spin resonance (ESR) spin-trapping technique. As a result, diphenylamine did not decrease the amount of radicals but rather increased it. It indicates that under the conditions of this study, gas-phase radicals were hardly trapped by radical scavengers and that the precursors to produce other kinds of radicals can exist. It was suggested that from the experiments using several peroxides, the precursors should be diacylperoxides produced from the combustion of PMMA.