Worm-like carbon shell chains produced from wood

Large-scale utilization of wood which command absolute majority in biomass for functional carbon precursors contributes to reduce greenhouse effect. Wood char generally has a limit on material usage because of its non-graphitic structure^1^, so we developed a new functional wood char by iron-, or nickel-catalyzed carbonization, which has a graphite-like structure with mesopores good for electroconductivity and liquid phase adsorption capacity for macro molecules^2-5^. However the fine structure of the wood char is still not clear. Here we report more than 70 wt % of iron-catalyzed wood char is filled with chained carbon shells formed by 3~20 defective stacking layers of carbon hexagonal planes, which look like nanometer-sized worms swarm. We name them "carbon shell chains". The discussion of the formation mechanism reveals that the wood cell wall plays an important role for their efficient production. They are stable at 1800 ºC under vacuum, but in air, burn under 600 ºC, and are perfectly conversed into hydrogen and carbon monoxide in a short time by steam at 900 ºC. The control of their decomposition will bring out a new talent in the wood char as a big source of supply for nano-graphite or nano-graphene, for which nanometer size and edge effects have recently attracted considerable attention^6^. In addition, a simple and easy preparation of carbon shell chains implies that they may be naturally produced on or in the earth rich in iron, and might be misinterpreted as nano-worms, though most of them may decompose into organic gases

Boiling heat transfer enhancement by nano-particles-assembled bi-porous layers

Nanoparticles-assembled bi-porous structure is newly proposed as boiling heat transfer enhancement technique. In order to assemble nanoparticles onto a heat transfer surface as a thin layer, a boiling adhesion method (BAM) is originally introduced in which, water or water/ethanol solution with mono-dispersed nanoparticles is dropped or sprayed onto a high temperature surface, and then the nanoparticles deposit onto the heat transfer surface during the boiling. In addition to that, it is expected that boiling bubbles can produce micro or milli scale of larger pores at the same time, which enables to fabricate bi-porous structure. Please download the full abstract below

The trends about body image and eating behavior among female college students

　Many Japanese people consider that “beauty equals a slim body”．Dissatisfaction with their body shape triggers the beginning of unnecessary and unscientific diet behaviors，and continuation of biased diet behaviors can lead to eating disorders．Such abnormal eating behaviors are more likely to occur at ages between late teens and early twenties (female college students)．The aim of the present study is to investigate the association between their types of body shape and the abnormal eating behaviors．　I performed a questionnaire，in order to assess Body Mass Index (BMI)，one’s body shape employing 9 silhouettes and Eating Attitude Test-26 (EAT26)．The questionnaire was distributed to 227 students at K University．196 students answered all questions of the questionnaire，and thus，they were included in the analysis set．　4％ were judged by EAT26 as having a strong tendency for abnormal eating behaviors．When it was analyzed in terms of the BMI-based type of body shape，a strong tendency for abnormal eating behaviors was seen in 0％ of thin individuals，4.4％ of ordinary individuals，and 16.6％ of obese individuals．Individuals with large body weight did not desire “excessively thin” body but “desired to reduce body weight from the current level”，while individual with small body weight “desired to become slightly thinner” even though they were aware of their current body shape as belonging to the category “thin.” In the analysis of EAT26，the results supported the possibility that the present subjects had a resistance to becoming obese，which in turn led to biased selection of foods，i.e.，food intake restriction for so-called dieting．　The results of the present study revealed that the potential of developing eating disorders is not directly related to the actual obesity level．More specifically，the subjects having any type of body shape had the “desire to become thin,” and thus，they had the possibility of developing eating disorders

Application of nanoparticles-assembled bi-porous structures to power electronics cooling

Nanoparticles-assembled bi-porous structure is newly proposed and its potential to enhance the boiling heat transfer is evaluated in order to develop a new cooling device toward 300W/cm2 of on-vehicle inverter cooling. In order to assemble nanoparticles on to a heat transfer surface as a thin layer, a boiling adhesion method (BAM) is originally introduced in which, water or water/ethanol solution with mono-dispersed nanoparticles is dropped or sprayed onto a high temperature surface, and then the nanoparticles deposit onto the heat transfer surface during the boiling. In addition to that, it is expected that boiling bubbles can produce micro or milli scale of pores at the same time. In order to evaluate the applicability of the nanoparticles-assembled bi-porous structures, droplet behavior on a high temperature surface is visualized with a high speed camera The experimental results show that the boiling adhesion method can produce multi-scale pore structures composed of nano-scale pores and micro-scale pores and that the water droplet intensely boils and evaporates on a high temperature of a wall with nanoparticles-assembled bi-porous layer even under Leidenfrost conditions, which proves that the nanoparticles-assembled bi-porous structure enables the increase in both the critical heat flux and the boiling heat transfer in a nucleate boiling regim

Proposal of utilizing uni-directional porous copper for extremely high heat flux removal

This paper proposes new heat removal devices utilizing uni-directional porous copper against extremely high heat flux conditions. Before designing those, we discuss some key parameters of porous media to enable a high heat flux removal over 10 MW/m2 at a low flow rate of water, which are effective thermal conductivity, permeability, liquid supply to a heat transfer surface, and contact thermal resistance between the porous medium and the heat transfer surface. These discussions indicate utilizing the uni-directional porous media as shown in Fig. 1 from the view point of its higher thermal conductivity, direct supply of cooling liquid toward the heat transfer surface, discharge of vapor, reduction in flow resistance and the thermal contact resistance Please download the full abstract below

Near-Ultraviolet and Visible Spectroscopy of HAYABUSA Spacecraft Re-entry

HAYABUSA is the first spacecraft ever to land on and lift off from any celestial body other than the moon. The mission, which returned asteroid samples to the Earth while overcoming various technical hurdles, ended on June 13, 2010, with the planned atmospheric re-entry. In order to safely deliver the sample return capsule, the HAYABUSA spacecraft ended its 7-year journey in a brilliant "artificial fireball" over the Australian desert. Spectroscopic observation was carried out in the near-ultraviolet and visible wavelengths between 3000 and 7500 \AA at 3 - 20 \AA resolution. Approximately 100 atomic lines such as Fe I, Mg I, Na I, Al I, Cr I, Mn I, Ni I, Ti I, Li I, Zn I, O I, and N I were identified from the spacecraft. Exotic atoms such as Cu I, Mo I, Xe I and Hg I were also detected. A strong Li I line (6708 \AA) at a height of ~55 km originated from the onboard Li-Ion batteries. The FeO molecule bands at a height of ~63 km were probably formed in the wake of the spacecraft. The effective excitation temperature as determined from the atomic lines varied from 4500 K to 6000 K. The observed number density of Fe I was about 10 times more abundant than Mg I after the spacecraft explosion. N2+(1-) bands from a shock layer and CN violet bands from the sample return capsule's ablating heat shield were dominant molecular bands in the near-ultraviolet region of 3000 - 4000 \AA. OH(A-X) band was likely to exist around 3092 \AA. A strong shock layer from the HAYABUSA spacecraft was rapidly formed at heights between 93 km and 83 km, which was confirmed by detection of N2+(1-) bands with a vibration temperature of ~13000 K. Gray-body temperature of the capsule at a height of ~42 km was estimated to be ~2437 K which is matched to a theoretical prediction. The final message of the HAYABUSA spacecraft and its sample return capsule are discussed through our spectroscopy.Comment: Accepted for publication in PASJ, 22 pages, 7 figures, 6 table

Исследование влияния термической обработки на вид излома ударных образцов и трещиностойкость сталей типа 06Г2МБТ

В работе исследованы образцы Шарпи низкоуглеродистых трубных сталей типа 06Г2МБТ после контролируемой прокатки и ускоренного охлаждения и термической обработки по различным режимам. На основе литературных данных и результатов собственных экспериментов проведен анализ поверхностей разрушения, изучено влияние температуры нагрева на уровень ударной вязкости стали и вид поверхности излома