Development of Sensor and Control Systems of a Wearable Robot to Walk on a Step

The goal of our study is to develop a system for walking on a step using a wearable robot. Our system consists of (1) sensing of a step from the movement of the walker, (2) detection of the foot placement state related to the step, and (3) generation of gait patterns of climbing and stepping down for the step. In the generation of gait patterns for the step, toe trajectories are generated according to the height of the step to avoid collision of the swinging leg with the step. The hip trajectory is generated by an optimization technique that minimizes the sum of the joint angular jerk of the robot subject to constraints on the hip position and the velocity at toe liftoff. Each joint angle trajectory is calculated from the generated trajectories by means of inverse kinematic equations. We investigated the feasibility of the proposed sensor and control systems for two steps with different heights.     

Ozonation of N-Nitrosamines in the Reverse Osmosis Concentrate from Water Recycling Applications

This study aims to evaluate the performance of ozone treatment for removing N-nitrosamines from reverse osmosis (RO) concentrate in water recycling applications. In the absence of any N-nitrosamine precursors, the destruction efficiency of N-nitrosamines was dependent on their molecular weight or the length of the alkyl chain in their molecular structure. Experiments conducted with RO concentrate showed that ozonation could lead to the formation of N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), resulting in an increase in concentrations of these N-nitrosamines. Nevertheless, ozonation was effective for destruction of N-nitrosamines with molecular weight greater than that of NDEA (102 g/mol).     

High‐temperature latent heat storage technology to utilize exergy of solar heat and industrial exhaust heat

Latent heat storage (LHS) using phase change materials is quite attractive for utilization of the exergy of solar energy and industrial exhaust heat because of its high‐heat storage capacity, heat storage and supply at constant temperature, and repeatable utilization without degradation. In this article, general LHS technology is outlined, and then recent advances in the uses of LHS for high‐temperature applications (over 100 °C) are discussed, with respect to each type of phase change material (e.g., sugar alcohol, molten salt, and alloy). The prospects of future LHS systems are discussed from a principle of exergy recuperation. In addition, the technologies to minimize exergy loss in the future LHS system are discussed on the basis of the thermodynamic analysis by ‘thermodynamic compass’. Copyright © 2016 John Wiley & Sons, Ltd.     

Improvement in thermal endurance of D-mannitol as phase-change material by impregnation into nanosized pores

This paper describes the control of the melting point and improvement of the thermal endurance of D-mannitol (melting point T_m = 440 K) as a phase-change material (PCM) by vacuum impregnation of the PCM into nanosized pores of porous SiO₂ grains. First, we examined the effects of the average pore size (D_P) of porous SiO₂ on T_m and latent heat (L) of PCM/SiO₂ composites. Second, we investigated the thermal endurance of the composites using constant temperature kinetics based on L of the PCM and composites. Third, we performed cyclic tests of melting and freezing on the composite to evaluate leakage of the PCM. Thermophysical properties of the samples were measured by differential scanning calorimetry, and the following results were obtained: (1) The impregnation ratio of the composites was 0.91–0.99; therefore, almost all pores were completely filled with the PCM. (2) T_m shifted to lower temperature with smaller D_P, reaching 413 K in case of the PCM/SiO₂ composite with a D_P of 11.6 nm (3) T_m was derived as a function of D_P from the Gibbs–Thomson equation taking into account the existence of a nonfreezing layer on the surface of the pore wall. (4) The duration of thermal degradation of the PCM/SiO₂ composite with D_P = 11.6 nm was three times longer than that of the pure PCM at a temperature that is 10 K more than each melting point. (5) The PCM/SiO₂ composite with D_P = 11.6 nm can use as a shape-stable PCM composite without leakage of PCM.     

Measurement of High-Temperature Elastic Properties of Ceramics Using a Laser Ultrasonic Method

Young's modulus and Poisson's ratio of SiC ceramics at temperatures >1400°C were obtained using a laser ultrasonics method that included a Fabry-Pérot interferometer (LUFP). At temperatures <1000°C, Young's modulus and Poisson's ratio measured using the LUFP method agreed well with those measured using standard contact methods, such as the resonance method and the ultrasonic pulse method. These results showed that the LUFP method is a powerful tool for measuring high-temperature elastic properties of advanced ceramics in a noncontact manner.     

Homogeneous Strain Introduction Using Reciprocation Technique in High-Pressure Sliding

Metallurgical and Materials Transactions A - This study examines strain distribution occurring in the high-pressure sliding (HPS) processing for rods of pure Al and an AZ61 alloy. The strain...     

Mutation Analysis of Radioresistant Early-Stage Cervical Cancer

Radiotherapy is a definitive treatment for early-stage cervical cancer; however, a subset of this disease recurs locally, necessitating establishment of predictive biomarkers and treatment strategies. To address this issue, we performed gene panel-based sequencing of 18 stage IB cervical cancers treated with definitive radiotherapy, including two cases of local recurrence, followed by in vitro and in silico analyses. Simultaneous mutations in KRAS and SMAD4 (KRAS^mt/SMAD4^mt) were detected only in a local recurrence case, indicating potential association of this mutation signature with radioresistance. In isogenic cell-based experiments, a combination of activating KRAS mutation and SMAD4 deficiency led to X-ray resistance, whereas either of these factors alone did not. Analysis of genomic data from 55,308 cancers showed a significant trend toward co-occurrence of mutations in KRAS and SMAD4. Gene Set Enrichment Analysis of the Cancer Cell Line Encyclopedia dataset suggested upregulation of the pathways involved in epithelial mesenchymal transition and inflammatory responses in KRAS^mt/SMAD4^mt cancer cells. Notably, irradiation with therapeutic carbon ions led to robust killing of X-ray-resistant KRAS^mt/SMAD4^mt cancer cells. These data indicate that the KRAS^mt/SMAD4^mt signature is a potential predictor of radioresistance, and that carbon ion radiotherapy is a potential option to treat early-stage cervical cancers with the KRAS^mt/SMAD4^mt signature.     

Fracture and acoustic emission characteristics of glass fiber reinforced plastics panels for hot water

This study deals with the fracture process and acoustic emission (AE) characteristics of a randomly oriented E-glass fiber mat reinforcement with a crosslinked polyester. These panels were evaluated after they were immersed in hot water. The fiber volume content of the panel was 19%. Glass fiber reinforced plastics (GFRP) panels wer immersed in water at 81°C. Bending and AE monitoring tests were Performed and after bending, the cross-section of the specimen was observed by an optical microscope and SEM. The influence of degradation, due to water immersion, on the changes of fracture process of GFRP is discussed. The dominant fracture mode of the virgin specimen was matrix cracks, whereas that of the immersed specimen was debondings at the fiber bundle/matrix and fiber/matrix interfaces. This change was caused by reduction of the bonding strength at the interface. The scale of fracture can be estimated by both AE amplitude and AE energy and this estimation method was used to estimate the fracture mode changes of GFRP panels immersed in hot water.