Phobos Environment Model and Regolith Simulant for MMX Mission

Phobos and Deimos, the two moons of Mars, are considered to be scientifically important and potential human mission's target. Martian Moons eXplorer (MMX) is the JAXA's mission to explore Phobos (and/or Deimos), which is scheduled to be launched in 2024. The main spacecraft of MMX will perform in-situ observations of both Phobos and Deimos, land on one of them (most likely, Phobos), and bring samples back to Earth. Small landing modules may be included in the mission as for the Hayabusa-2 mission. The designs of both the landing and sampling devices depend largely on the surface conditions of the target body and on how this surface reacts to an external action in the low gravity conditions of the target. Thus, the Landing Operation Working Team (LOWT) of MMX, which is composed of both scientists and engineers, is studying Phobos' surface based on previous observations and theoretical/experimental considerations. Though engineering motivation initiated this activity, the results will be extremely useful for scientific purposes

Optimization of the process parameters for the manufacturing of open-cells iron foams with high energy absorption

In this work the main results of the experimental research aimed to manufacture iron foams are reported. Iron powders (base metal) have been mixed with urea (filler agent) in different relative amounts (60% Fe- 40% urea, 50-50, 40-60 and 30-70) and then compressed in a cylindrical die in order to obtain a compact precursor. After compaction, the filler agent has been removed from each precursor in boiling water. The successive manufacturing step has been sintering and for this operation the optimum temperature has been found at 950 °C. Finally such foams have been subjected to compressive tests. Different amounts of Fe and urea match with different density and mechanical behavior in compressive tests. Energy absorbed during deformation has been calculated from the stress-strain compressive curve. Plateau stress, total strain and absorbed energy during deformation have been found strictly dependent from the iron/urea ratios

Size Distribution Measurements of Fine Particles Using Their Pearl Chain Formations under a DC Electric Field

This book bridges three different fields: nanoscience, bioscience, and environmental sciences. It starts with fundamental electrostatics at interfaces and includes a detailed description of fundamental theories dealing with electrical double layers around a charged particle, electrokinetics, and electrical double layer interaction between charged particles. The stated fundamentals are provided as the underpinnings of sections two, three, and four, which address electrokinetic phenomena that occur in nanoscience, bioscience, and environmental science. Applications in nanomaterials, fuel cells, electronic materials, biomaterials, stems cells, microbiology, water purification, and humic substances are discussed

Erasing Data and Recycling of Optical Disks

Optical disks, DVDs and CDs, are convenient recording media on which to safely store data for a long period of time. However, the complete data erasure from recorded media is also important for the security of the data. After erasure of data from optical disks, recycling the material is needed in order to recover the valuable components of the optical disks. Here, data erasure methods for optical disks are discussed in the view of material recycling. The main finding of the study is that the explosion of optical disks in water is a very suitable method for complete erasure of data on the disks as well as recycling of their materials

Treatment of arsenic-containing acid mine drainage by micro-bubble flotation

Generally speaking, acid mine drainage (AMD) contains relatively high concentration of arsenic (As), which is a very toxic chemical element. A typical example is the Horobetsu sulfur mine, located in the northern Japan. The drainage from Holobetsu mine flows into Lake Toya, which without an effective treatment would affect the equilibrium of the ecosystem of the vicinity. Actually, the drainage from the Horobetsu mine is treated by using co-precipitation process with iron hydroxide in order to remove arsenic, followed by neutralization. The aim of the research is therefore to develop a new processing method for AMD, which could be another feasible treatment option. In other words, the objective is to investigate the removal of arsenic by micro-bubble flotation. The main finding of this study is that arsenic was effectively removed when mole ratio with sulfur of sulfating agent and arsenic was 6 and pH 2.8. The experimental results also suggested that arsenic concentration was reduced from 10.2 mg/L to less than 0.083 mg/L, indicating the efficiency of the micro-bubble flotation