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Accuracy and applicable range of a reconstruction technique for hybrid rockets
Nagata, Harunori,Nakayama, Hisahiro,Watanabe, Mikio,Wakita, Masashi,Totani, Tsuyoshi Techno-Press 2014 Advances in aircraft and spacecraft science Vol.1 No.3
Accuracy of a reconstruction technique assuming a constant characteristic exhaust velocity ($c^*$) efficiency for reducing hybrid rocket firing test data was examined experimentally. To avoid the difficulty arising from a number of complex chemical equilibrium calculations, a simple approximate expression of theoretical $c^*$ as a function of the oxidizer to fuel ratio (${\xi}$) and the chamber pressure was developed. A series of static firing tests with the same test conditions except burning duration revealed that the error in the calculated fuel consumption decreases with increasing firing duration, showing that the error mainly comes from the ignition and shutdown transients. The present reconstruction technique obtains ${\xi}$ by solving an equation between theoretical and experimental $c^*$ values. A difficulty arises when multiple solutions of ${\xi}$ exists. In the PMMA-LOX combination, a ${\xi}$ range of 0.6 to 1.0 corresponds to this case. The definition of $c^*$ efficiency necessary to be used in this reconstruction technique is different from a $c^*$ efficiency obtained by a general method. Because the $c^*$ efficiency obtained by average chamber pressure and ${\xi}$ includes the $c^*$ loss due to the ${\xi}$ shift, it can be below unity even when the combustion gas keeps complete mixing and chemical equilibrium during the entire period of a firing. Therefore, the $c^*$ efficiency obtained in the present reconstruction technique is superior to the $c^*$ efficiency obtained by the general method to evaluate the degree of completion of the mixing and chemical reaction in the combustion chamber.
The edible medicinal piano with antitumor activity used in Korea
Lee Sang-Rae,Harunori Ooda,Lee Sook-Young 한국자원식물학회 1999 한국자원식물학회 학술심포지엄 Vol.1999 No.-
Many plant species are used in Malaysia in folk medicine for the treatment of cancer. This paper presents some of these species with details on other ethnopharmacological uses, the known bioactivities and some chemical constituents of each of the species given. It is normal practice in traditional medicine that one species of plant is used to treat various ailments. Thus the plant species listed are all used to treat cancer but have various other ethnophrmacological uses as well, some with few other uses and rest with many other uses. Information on bioactivities of each species resulting from tests on human and experimental animals are also given. Proven bioactivities give strength to ethnopharmacological claims on the efficacies of plant resources in the treatment of cancer and various other ailments but will but will not necessarily lead to the production of new pharmaceutical drugs. Many of the known chemical constituents of each species are given. This shows the richness and variety of chemicals containes in each of the species listed, The chemicals listed may or may not prove to be important in the pharmaceutical sciences but is an indication of what each species contatin in thrms of plant chemicals, It is a well known fact that many of the pharmaceutical prescriptions in present day use are of plant origin and semi-synthetic or fully synthetic chemicals produced using knowledge gained from studies of phytochemicals. Thus the paper presented will give useful information and also shows the richness of plant species that have high potentials for the development of anti-cancer resources from plants in Malaysia.
Investigation of axial-injection end-burning hybrid rocket motor regression
Saito, Yuji,Yokoi, Toshiki,Neumann, Lukas,Yasukochi, Hiroyuki,Soeda, Kentaro,Totani, Tsuyoshi,Wakita, Masashi,Nagata, Harunori Techno-Press 2017 Advances in aircraft and spacecraft science Vol.4 No.3
The axial-injection end-burning hybrid rocket proposed twenty years ago by the authors recently recaptured the attention of researchers for its virtues such as no ${\zeta}$ (oxidizer to fuel mass ratio) shift during firing and good throttling characteristics. This paper is the first report verifying these virtues using a laboratory scale motor. There are several requirements for realizing this type of hybrid rocket: 1) high fuel filling rate for obtaining an optimal ${\zeta}$; 2) small port intervals for increasing port merging rate; 3) ports arrayed across the entire fuel section. Because these requirements could not be satisfied by common manufacturing methods, no previous researchers have conducted experiments with this kind of hybrid rocket. Recent advances in high accuracy 3D printing now allow for fuel to be produced that meets these three requirements. The fuel grains used in this study were produced by a high precision light polymerized 3D printer. Each grain consisted of an array of 0.3 mm diameter ports for a fuel filling rate of 98% .The authors conducted several firing tests with various oxidizer mass flow rates and chamber pressures, and analysed the results, including ${\zeta}$ history, using a new reconstruction technique. The results show that ${\zeta}$ remains almost constant throughout tests of varying oxidizer mass flow rates, and that regression rate in the axial direction is a nearly linear function of chamber pressure with a pressure exponent of 0.996.