Tadao Yoshida

Estimation of Δf of nitro derivatives of benzene and toluene using AM1 and DSC

Abstract The AM1 molecular orbital method and reduced pressure differential scanning calorimetry(RP-DSC) were applied to nitro derivatives of benzene and toluene for estimating Δf(1) and Δf(c). The heats of phase change were determined by RP-DSC with moderate accuracy and the combination of the heats and Δf(g) estimated by AM1 gave Δf in condensed phases which are similar to those found in literatures.

EFFECT OF EXHAUST FROM ALCOHOL FUEL ON OZONE FORMATION IN THE ATMOSPHERE

Abstract 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.

Thermal decomposition of sponge blowing agents by pressure thermal analysis

Abstract The thermal decomposition of six sponge blowing agents was investigated with a pressure differential scanning calorimeter and a pressure thermobalance to evaluate their thermal hazard. Decomposition heats and kinetic constants in an atmosphere of inert gas or air were obtained using thermal analysis methods. A positive gas pressure was employed in the elucidation of the decomposition behavior of these substances because some of them evaporate during linear heating at atmospheric pressure. The decomposition heats and exothermic onset temperatures of most of the sponge blowing agents tended to increase with a pressure increase in nitrogen or air. The evolution heats, ranging from about 150 to 500 cal/g (in air at 1 atmosphere), were increased to a range of about 250 to 1000 cal/g by a pressurized air atmosphere of 5.3 MPa. Under pressure thermogravimetry conditions the rate of decomposition increased with increasing gas pressure, suggesting a distinction in the decomposition mechanism. The influence of heating rate on the decomposition heat and weight change is also discussed, and kinetic constants such as activation energies at 1 atm are compared with those obtained in pressurized gas atmospheres.

Evaluation of explosive properties of organic peroxides with a modified Mk III ballistic mortar

Abstract Ballistic mortar tests using the Mk III F mortar have been carried out to examine a procedure for assessing the explosive hazard of organic peroxides. The explosive properties of an organic peroxide can be evaluated from two series of experiments, for propagation and power of explosion, and for shock sensitivity. Among seven organic peroxides tested, tert-butyl peroxybenzoate and dibenzoyl peroxide have shown high shock sensitivity and explosive powers of 40 and 25% of TNT, respectively. Di-tert-butyl peroxide showed medium sensitivity and the power of 30% of TNT. Cumyl hydroperoxide, 80% in cumene, dibenzoyl peroxide, 75% with water, dicumyl peroxide and dilauroyl peroxide did not propagate explosion.

Performance of pressure vessel test concerned with heating rate of pressure vessel and bursting pressure of rupture disk

Abstract Heating rate characteristics of samples were examined for Dutch and US pressure vessels and sample cups with round and flat bottoms. The heating rate i The ‘bursting pressure’ of rupture disks were measured by the N2 pressure method and the ADCA (azodiacarbonamide) decomposition method which is The maximum pressure by ADCA decomposition was examined by means of pressure sensors, strain gauges and a Bourdon gauge in order to minimize the disper The results can best be summarized as follows: The maximum pressure attainable increases with sample mass; the dispersion in the maximum pressure data The round bottom cup gives smaller maximum pressure, albeit with larger data dispersion, than the flat one.

Shock sensitivity of blasting explosive cartridges

Abstract The undersand variable gap–initiator test was applied to most Japanese blasting explosive cartridges and found useful as the sensitivity test for the cartridges. The recent Japanese watergel and emulsion explosives were shown to be more shock–sensitive than previous ones. The blast noise in the undersand explosion was shown to decrease when the depth of sand cover the cartridge was increased. For 100g of explosive, a sand layer 20cm deep was effective in reducing the blast noise, when the depth of the sand layer was increased, there was no additional effect. All blasting explosives excluding Kuro Carlit were not ignited by a small gas flame. A cartridge of 100g Kuro Carlit was ignited undersand but did not show the phenomenon of deflagration to detonation

Evaluation of the deflagration hazards of organic peroxides by the revised time-pressure test

Abstract The revised Time-Pressure test has been applied to organic peroxides to evaluate their deflagration hazards. Liquid organic peroxides were also tested successfully using a firing method with a fusehead. The results show that the ignition sensitivity and the violence of deflagration can be obtained from the amount of igniting material giving the apparent maximum rate of pressure rise, and its maximum rate, respectively. From an evaluation of the deflagration hazards of many types of organic peroxides, it is also shown that the ignition sensitivity and the violence of deflagration for each organic peroxide may have a tendency to increase with increasing active oxygen content among the same type of organic peroxide, with a few exceptions and that the ignition sensitivity and the violence of deflagration for each type of organic peroxide may decrease in the following order, given the same active oxygen content: diacyl peroxides > peroxyesters > dialkyl peroxides > hydroperoxides.