Flight Demonstration of Electrostatic Thruster under Micro-Gravity

Based on a new concept, a low power electrostatic thruster is being developed for its application to 50 kg class satellite, which is named “Microwave Engine”. The proto-model (PM) of the microwave engine was manufactured and the qualification test (QT) was conducted. The estimated performances are 1250 seconds in specific impulse, 0.36mN in thrust and 10% in thrust efficiency when it is operated at 26.6W. To evaluate the feasibility of its accelerating mechanism, the flight demonstration of a plasma thruster is implemented under microgravity. The demonstrated thruster has an aperture of 19 mm in diameter. The same accelerating mechanism as Microwave Engine is applied to the plasma thruster although there is a difference in the mechanism of generating plasma. The flight demonstrator utilizes the glow discharge while the microwave discharge is applied to Microwave Engine. In this study, the thrust is estimated based on the flight path of the plasma thruster under microgravity, the swing of its pendulum under 1G and the beam theory of its copper wires. These corresponding thrusts are 0.36 mN, 0.20 mN and 0.11 mN, respectively. In addition, a series of its flight images is shown in this paper. As a result, the reasonable flight performance validates the accelerating mechanism of Microwave Engine

Continuous 5-hydroxymethylfurfural production from monosaccharides in a microreactor

5-Hydroxymethylfurfural (HMF) was effectively produced from monosaccharides in a microreactor. A biphasic reaction system was employed to achieve the immediate extraction of produced HMF and suppress the overreaction. A microreactor was utilized to ensure that the reaction occurred under segmented flow to enhance the extraction efficiency. Through many attempts using phosphate buffer saline (PBS) as the reaction phase and 2-sec-butyl phenol (2BP) as the extraction phase, the favorable conditions were determined. By using PBS with pH of 2.0 and 2BP at a volume ratio of 3 to PBS, 80.9 mol % of fructose and 75.7 mol % of glucose were converted into HMF, respectively, at 180 °C. By comparing the results obtained through monophasic reactions, it was confirmed that the biphasic system successfully suppressed both the overreaction and the byproducts. The system employed only a simple experimental apparatus and the acid solution and organic solvent reagents without any complex expensive catalyst

Experimental Investigation of the Cs Behavior in the Cesiated H- Ion Source During High Power Long Beam Operation

The behavior of the Cesium (Cs) in the Cs-seeded negative ion sources has been investigated experimentally under the beam accelerations of up to 0.5 MeV. The pulse length was extended to 100 s to catch the precise variations of the Cs D2 emission, discharge power, negative ion current and temperatures in the ion source. The variations of the negative ions were estimated by the beam current and the heat loads in the accelerator. This experiment shows that the buildup of temperature in the chamber walls lead to the evaporation of deposited Cs to enter the plasma region and influence the H- ion production. The H- ion beams were sustained stably by reducing the temperature rise of the chamber wall below 50 ℃. A stable long pulse beam could be achieved through the temperature control of the surfaces inside the source chamber walls

RBCS1A and RBCS3B, two major members within the Arabidopsis RBCS multigene family, function to yield sufficient Rubisco content for leaf photosynthetic capacity

Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) small subunit (RBCS) is encoded by a nuclear RBCS multigene family in many plant species. The contribution of the RBCS multigenes to accumulation of Rubisco holoenzyme and photosynthetic characteristics remains unclear. T-DNA insertion mutants of RBCS1A (rbcs1a-1) and RBCS3B (rbcs3b-1) were isolated among the four Arabidopsis RBCS genes, and a double mutant (rbcs1a3b-1) was generated. RBCS1A mRNA was not detected in rbcs1a-1 and rbcs1a3b-1, while the RBCS3B mRNA level was suppressed to ∼20% of the wild-type level in rbcs3b-1 and rbcs1a3b-1 leaves. As a result, total RBCS mRNA levels declined to 52, 79, and 23% of the wild-type level in rbcs1a-1, rbcs3b-1, and rbcs1a3b-1, respectively. Rubisco contents showed declines similar to total RBCS mRNA levels, and the ratio of Rubisco-nitrogen to total nitrogen was 62, 78, and 40% of the wild-type level in rbcs1a-1, rbcs3b-1, and rbcs1a3b-1, respectively. The effects of RBCS1A and RBCS3B mutations in rbcs1a3b-1 were clearly additive. The rates of CO2 assimilation at ambient CO2 of 40 Pa were reduced with decreased Rubisco contents in the respective mutant leaves. Although the RBCS composition in the Rubisco holoenzyme changed, the CO2 assimilation rates per unit of Rubisco content were the same irrespective of the genotype. These results clearly indicate that RBCS1A and RBCS3B contribute to accumulation of Rubisco in Arabidopsis leaves and that these genes work additively to yield sufficient Rubisco for photosynthetic capacity. It is also suggested that the RBCS composition in the Rubisco holoenzyme does not affect photosynthesis under the present ambient [CO2] conditions