On March 11, 2011, a massive earthquake (magnitude 9.0) and accompanying tsunami hit the Tohoku region of eastern Japan. Since then, the Fukushima Daiichi Nuclear Power Plants have been facing a crisis due to the loss of all power that resulted from the meltdown accidents. Three buildings housing nuclear reactors were seriously damaged from hydrogen explosions, and, in one building, the nuclear reactions became out of control. It was too dangerous for humans to enter the buildings to inspect the damage because radioactive materials were also being released. In response to this crisis, it was decided that mobile rescue robots would be used to carry out surveillance missions. The mobile rescue robots needed could not be delivered to the Tokyo Electric Power Company (TEPCO) until various technical issues were resolved. Those issues involved hardware reliability, communication functions, and the ability of the robots' electronic components to withstand radiation. Additional sensors and functionality that would enable the robots to respond effectively to the crisis were also needed. Available robots were therefore retrofitted for the disaster reponse missions. First, the radiation tolerance of the electronic componenets was checked by means of gamma ray irradiation tests, which were conducted using the facilities of the Japan Atomic Energy Agency (JAEA). The commercial electronic devices used in the original robot systems operated long enough (more than 100 h at a 10% safety margin) in the assumed environment (100 mGy/h). Next, the usability of wireless communication in the target environment was assessed. Such tests were not possible in the target environment itself, so they were performed at the Hamaoka Daiichi Nuclear Power Plants, which are similar to the target environment. As previously predicted, the test results indicated that robust wireless communication would not be possible in the reactor buildings. It was therefore determined that a wired communication device would need to be installed. After TEPCO's official urgent mission proposal was received, the team mounted additional devices to facilitate the installation of a water gauge in the basement of the reactor buildings to determine flooding levels. While these preparations were taking place, prospective robot operators from TEPCO trained in a laboratory environment. Finally, one of the robots was delivered to the Fukushima Daiichi Nuclear Power Plants on June 20, 2011, where it performed a number of important missions inside the buildings. In this paper, the requirements for the exploration mission in the Fukushima Daiichi Nuclear Power Plants are presented, the implementation is discussed, and the results of the mission are reported.

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We report recent results from field experiments conducted with a team of ground and aerial robots engaged in the collaborative mapping of an earthquake‐damaged building. The goal of the experimental exercise is the generation of three‐dimensional maps that capture the layout of a multifloor environment. The experiments took place in the top three floors of a structurally compromised building at Tohoku University in Sendai, Japan that was damaged during the 2011 Tohoku earthquake. We provide details of the approach to the collaborative mapping and report results from the experiments in the form of maps generated by the individual robots and as a team. We conclude by discussing observations from the experiments and future research topics. © 2012 Wiley Periodicals, Inc.

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Thc zonic coiiductzng p o l y m e r gel film (IGPF) octunlor 1 5 a per/iuorosulfoiiic aczd menibran( plaied with plniinum on t i s both surfaces It hends zii water and ? n ulcl condifioii by applyzng a low voltage of 1 5 v l o ~l s surfoces Tlizr p h e n o m e n o n w a s dzscowred 211 1992 Thc p r i n c z p l r of the inoizon i s ctzll u n k n o w n 7hi9 p n p e r dz4cusbes %dznieiiszoitnl linear opproxzirinlc rnodclinq of llic ICPF nctnalor The aulhors are proposzng n d y n a m~c model of thc a c i u n i o r colisastang of o n rlcclrzcal slagc, N d r e s s generatzon stage and a inechonical giage I n the stress generafaon doge, tzine drriocittze of c u i r f n l qericraies the aiiteriial stress wzth a second degree d e l a y Erpanston and contraction of t n c h surfocc induce bending inotaon zn t h e inechanzcal s i a q f Sziniilalzon results were zn agnoenient wzth actual icsponscs

In this paper, a white-box model of Nafion-Pt composite actuators considering the following physical phenomena is proposed: 1) ionic motion by electric field, 2) water motion by ion-drag, 3) swelling and contraction of the membrane, 4) momentum effect, 5) electrostatic force, and 6) conformation change. Computer simulation showed the following results. 1) The simulated motions agreed with experimental results improving the accuracy in comparison with the conventional models, especially on the time of the maximum displacement. 2) The nonlinear relation between input voltage and the maximum displacement was explained.

Chromosomal double-strand breaks (DSBs) in mammalian cells are usually repaired through either of two pathways: end-joining (EJ) or homologous recombination (HR). To clarify the relative contribution of each pathway and the ensuing genetic changes, we developed a system to trace the fate of DSBs that occur in an endogenous single-copy human gene. Lymphoblastoid cell lines TSCE5 and TSCER2 are heterozygous (+/-) or compound heterozygous (-/-), respectively, for the thymidine kinase gene (TK), and we introduced an I-SceI endonuclease site into the gene. EJ for a DSB at the I-SceI site results in TK-deficient mutants in TSCE5 cells, while HR between the alleles produces TK-proficient revertants in TSCER2 cells. We found that almost all DSBs were repaired by EJ and that HR rarely contributes to the repair in this system. EJ contributed to the repair of DSBs 270 times more frequently than HR. Molecular analysis of the TK gene showed that EJ mainly causes small deletions limited to the TK gene. Seventy percent of the small deletion mutants analyzed showed 100- to 4,000-bp deletions with a 0- to 6-bp homology at the joint. Another 30%, however, were accompanied by complicated DNA rearrangements, presumably the result of sister-chromatid fusion. HR, on the other hand, always resulted in non-crossing-over gene conversion without any loss of genetic information. Thus, although HR is important to the maintenance of genomic stability in DNA containing DSBs, almost all chromosomal DSBs in human cells are repaired by EJ.

The ICPF (Ionic Conducting Polymer gel Film) actuator is a new high polymer gel actuator by which revolutionary robotic mechanisms are expected. Actuator models for CAE are essential to the robotic design. However, present black/gray-box models of ICPF cannot express its nonlinear characteristics with enough accuracy, In this paper, a white-box actuator model is proposed on the basis of physicochemical hypotheses on the motion principle which are supported at present. In this model, travel of sodium ions and water molecules in the actuator membrane is modeled. Internal stress is generated by swell and contraction of the gel by water content change, electrostatic force of jixed sulfonic acid groups, and momentum conservation effect. Simulation results show higher accuracy on transient response and nonlinear characteristics in comparison with conventional models.