Burning Rate Augmentation of BAMO Based Propellants

Thermal decomposition and the burning properties of BAMO based propellants with HMX or AN/HMX have been investigated. The heat generated by the azide binder decomposition initiated and accelerated the thermal decomposition of HMX and AN. Ammonium perchlorate (AP) and lead stearate with carbon black significantly altered the mechanisms of the thermal decomposition and the burning properties of the HMX based propellants. AP showed an increase in burning rate with a slight decrease in burning rate pressure exponent. The lead catalyst yielded high value of the burning rate with the lowest pressure exponent. The ammonium dichromate also influenced the mechanisms of the thermal decomposition and the burning properties of the AN/HMX samples. The combination of ammonium dichromate and copper chromite was the most effective on the burning rate augmentation of AN/HMX based propellants. AN sublimed and evaporated from the condensed phase and mainly reacted exothermically in the gas phase HMX and AN/HMX based propellants showed smokeless burning characteristics in the small rocket motor combustion tests.     

Disintegration process of yttria-stabilized zirconia ceramics using hydrothermal conditions

Capability of the recycling of high strength and high fracture toughness yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) sintered body utilizing “low-temperature annealing degradation” phenomenon was investigated. Hydrothermal treatment was employed to induce the phase transformation from tetragonal to monoclinic zirconia and to disintegrate the Y-TZP sintered body. 3 mol% Y₂O₃–ZrO₂ specimens sintered at 1,550 °C and more were disintegrated without leaving the original appearances when the treatment temperature was between 200 °C and 400 °C. The size of the disintegrated fragments of Y-TZP sintered body was much affected by hydrothermal treatment conditions. Only with hydrothermal treatment and simple ball milling, the sintered body was pulverized into the primary particle level. This technique is expected to apply to a sustainable recycling system for the zirconia ceramics, which restrains an energy consumption compared to crushing zirconia using mechanical procedures.     

Ethological data mining: an automata-based approach to extract behavioral units and rules

We propose an efficient automata-based approach to extract behavioral units and rules from continuous sequential data of animal behavior. By introducing novel extensions, we integrate two elemental methods—the N-gram model and Angluin’s machine learning algorithm into an ethological data mining framework. This allows us to obtain the minimized automaton-representation of behavioral rules that accept (or generate) the smallest set of possible behavioral patterns from sequential data of animal behavior. With this method, we demonstrate how the ethological data mining works using real birdsong data; we use the Bengalese finch song and perform experimental evaluations of this method using artificial birdsong data generated by a computer program. These results suggest that our ethological data mining works effectively even for noisy behavioral data by appropriately setting the parameters that we introduce. In addition, we demonstrate a case study using the Bengalese finch song, showing that our method successfully grasps the core structure of the singing behavior such as loops and branches. Yasuki Kakishita and Kazutoshi Sasahara have contributed equally to this work.     

Advanced energy saving in the reaction section of the hydro-desulfurization process with self-heat recuperation technology

The reaction section of the naphtha hydro-desulfurization (HDS) process is a heating and cooling thermal process consisting of a feed/effluent heat exchanger and a fired heater. Energy savings are fundamentally made as a result of the maximized heat recovery in the heat exchanger and the reduced heat duty of the fired heater. To achieve further energy saving in the process, “self-heat recuperation technology” (SHRT) was adopted. In this technology, a compressor was introduced. The suction side of the compressor needed a lower pressure and the feed stream evaporated much easily. The discharged side of the compressor satisfied the operating conditions of both pressure and temperature at the inlet of the reactor. And the reactor effluent stream was able to be used completely to preheat and vaporize the feed stream. All the heat in the process stream was re-circulated without using a fired heater. SHRT was applied to the naphtha HDS process of 18,000 barrel per stream day (BPSD) in the refinery and the mass and energy balance of the process was calculated using commercially available simulation software, Invensys PROII version 8.1. This process-simulation case study confirmed that despite there being no more energy saving potential in the conventional process that makes use of a fired heater, the advanced process with SHRT can reduce the energy consumption significantly by using the recuperated heat of the feed stream.     

An innovative modularity of heat circulation for fractional distillation

A novel modularity of heat circulation for distillation process, which reduces the energy consumption, is proposed. By incorporating compressors and heat exchangers, the heat of the distillate is recuperated and exchanged with the heat of the feed streams. The proposed technology achieves the reduction in the required energy more than 75% as compared with a benchmark process which uses external heat source for heating. This shows the proposed modularity of heat circulation for distillation process is very promising technology to drastically reduce energy demand for distillation.     

Polymerization of β-lactoglobulin and bovine serum albumin at oil-water interfaces in emulsions by transglutaminase

Polymerization of β-lactoglobulin and bovine serum albumin at the oil—water interfaces in n-tetradecane-in-water emulsions induced by the transglutaminase reaction was studied. The emulsions were incubated with transglutaminase for various times, and adsorbed and unadsorbed protein fractions at the oil—water interfaces were analyzed by sodium dodecyl sulfate—polyacrylamide gel electrophoresis. While only monomers were detected in the unadsorbed fractions, polymers were observed in the adsorbed fractions of the both proteins. The sizes and amounts of the polymers increased with incubation time. The incubation with transglutaminase caused much flocculation of the emulsion stabilized by β-lactoglobulin. An increase in viscosity was also observed with the flocculation. The flocculation was probably initiated by the formation of ε-(γ-glutamyl)-lysyl isopeptide bonds between β-lactoglobulin molecules adsorbed on different oil droplets. In the case of the emulsion stabilized by bovine serum albumin, however, the flocculation and the increase in viscosity occurred to only limited extents by the transglutaminase reaction. This suggests that ε-(γ-glutamyl)-lysyl isopeptide bonds induced by the transglutaminase reaction were formed only between neighboring molecules of bovine serum albumin on the same droplet.     

Multilateral analysis of increasing collective dose and new ALARA programme

JAPC (The Japan Atomic Power Company) is the only electric power company that operates different types of nuclear reactors in Japan; it operates two BWRs (boiling water reactors), one pressurised water reactor and one gas cooled reactor. JAPC has been conducting various activities aimed at reducing radiation dose received by workers for over 45 y. Recently, the collective dose resulting from periodic maintenance has increased at each plant because of the replacement of large equipment and the unexpected extension of the outage period. In particular, the collective dose at Tokai-2 is one of the highest among Japanese BWR plants((1)), owing to the replacement and strengthening of equipment to meet earthquake-proof requirements. In this study, the authors performed a multilateral analysis of unacceptably a large collective dose and devised a new ALARA programme that includes a 3D dose prediction map and the development of machines to assist workers.     

Competitive adsorption of α-lactalbumin in the molten globule state

The molten globule state of α-lactalbumin is a partially denatured form with native-like secondary structure and disordered tertiary structure. Using circular dichroism measurements, it was demonstrated that the molten globule state was produced by decreasing the pH to 2.0 at 25°C or by removing bound Ca²⁺ by treatment with ethylenediamine—tetraacetic acid (EDTA) at pH 7.5 and 40°C. Tension measurements showed that α-lactalbumin in the molten globule state is more easily unfolded at liquid interfaces than is the native protein. Results of competitive adsorption experiments involving α-lactalbumin and β-lactoglobulin at the oil droplet surface in emulsions are consistent with preferential adsorption of α-lactalbumin during emulsification when it is in the molten globule state. In contrast to the difficulty of exchange between α-lactalbumin and β-lactoglobulin at the oil-water interface in emulsions at 25°C, it has been found that the two whey proteins are able partially to displace one another from the oil—water interface at 40°C. While native α-lactalbumin was found to be readily displaced from the oil—water interface by β-lactoglobulin at 40°C, it was found that α-lactalbumin in the molten globule state in the presence of EDTA at 40°C had itself the capacity for displacing β-lactoglobulin from the interface.     

Exergy recuperative CO2 gas separation in pre-combustion capture

The integrated coal gasification combined cycle (IGCC) can achieve higher power generation efficiency than conventional pulverized coal combustion power plants. However, a CO₂ capture process prevents improving power generation efficiency of IGCC, because CO₂ separation from gas mixtures requires huge amounts of energy. Therefore, in this study, we analyzed the CO₂ separation process in the pre-combustion capture process using a process simulator (PRO/II) in the steady state, and proposed a new process using a modularity based on self-heat recuperation (SHR) technology to decrease energy consumption. Pre-combustion capture was applied in the IGCC plant, which involved coal gasification and CO-shift conversion with CO₂ capture. The results show that the energy consumption for the CO₂ separation process using SHR was decreased by two-thirds. This means that the power generation efficiency can be improved by SHR compared with conventional IGCC with a CO₂ capture process.