Currently, the production and installation quantity of photovoltaic modules is has been increasing rapidly. Meanwhile, the failure cases are also increasing. Accordingly, many failures are results of the Hot-Spot phenomenon. This is a phenomenon in which the entire or part of the defective cell becomes hot when shadow occurs on the cell for a long period. In severe cases, the phenomenon causes breaking of the cell and a fire. While there are many Hot-Spot inspection methods, such as using infrared cameras, the inspection instruments of these methods are expensive, and these methods also require a lot of time and effort during the inspection. Previously, the authors proposed a Hot-Spot detection system included into PCS. In this paper, we proposed plug-in type Hot-Spot detection system, and report about effectiveness of the system.
Many food wastes dispose from mainly developed countries including Japan, on the other hand a drain of phosphatic fertilizer is an issue of sustainable agriculture. Here we investigated effective utilization of the food wastes for agriculture, and focused on coffee grounds which is disposed of in a large quantity and difficult to reuse. It is difficult to use the coffee grounds for agricultural materials (ex; fertilizer, soil conditioner), because the coffee grounds are high carbon to nitrogen (C/N) ratio and contains a kind of plant growth inhibitor. Hence, the water (coffee grounds extract) stained out coffee grounds was used. Japanese mustard spinach (Brassica rapa var. prviridis) growth (fresh weight, dry weight and shoot length) was enhanced by applying the coffee grounds extract, and the growth ratio was almost same as plants applied commercial liquid fertilizer. We therefore suggest that the coffee grounds extract may use fertilizer in agriculture.
Adhesion induced by homogeneous low voltage EB-irradiation (HLEBI) under O2 partial pressure from 0.02 mol% to 20 mol% in N2 gas atmosphere of CFRP/Al lamination has been successfully developed. Its adhesive tensile shear strength of CFRP/Al with 0.30 MGy-HLEBI under optimal O2 partial pressure in N2 atmospher of 0.2 mol% is 8.2 MPa, which is about 1.4 times higher than that (5.9 MPa) of CFRP/Al untreated.
We investigated the thermoelectric properties of electrodeposited Sb-Te thin films using thermal annealing and incorporating diffusion barrier layer between the stainless steel substrate and the Sb-Te thin film. Molybdenum (Mo) and nickel (Ni) films were used as a diffusion barrier layer. Surface morphology was observed by scanning electron microscope, and crystallographic characteristic was examined by X-ray diffraction analysis. In-plane thermoelectric properties, in terms of the electrical conductivity, Seebeck coefficient and power factor, were measured at room temperature. It was found that Sb-Te thin film with Mo layer exhibited higher thermoelectric performance compared to that of Sb-Te thin film with no diffusion barrier layer. This is because the impurity atoms from the substrate and Mo layer itself did not diffuse so much into Sb-Te layer. On the other hand, Sb-Te thin film with Ni layer exhibited the lower thermoelectric properties owing to the diffusion of Ni atoms into the Sb-Te thin film. Therefore, incorporation of Mo layer is beneficial to improve the thermoelectric properties of Sb-Te thin films by thermal annealing.
When developing rehabilitation assist suits, safety consideration for patients is one of the most important issues. In this paper, we propose an ankle joint assist suit with a velocity-based safety device and a commercial torque limiter. The velocity-based safety device switches off the assist suit’s motor if it detects an unexpected high joint angular velocity. The torque limiter cuts off the torque transmission if it detects an unexpected high joint torque. These devices work even when the assist suit’s computer breaks down, because they consist of only passive mechanical components without actuators, controllers, or batteries. First, we describe the design requirements for this assist suit. Next, we clarify the relationship between the design requirements and the assist suit parts by using Kato’s multispace-quality function deployment (M-QFD). Finally, we present the assist suit design incorporating this relationship.
A joint between the carbon fibers (CF) reinforced thermoplastic polycarbonate and titanium (Ti) with extremely large friction force induced by the broad fiber interface was successfully prepared by using both electron beam melting process to wrap one side of the CF into the Ti and hot-press under air to wrap the other side of CF into polycarbonate (PC). The joint tensile strength was higher than those of glue and spontaneous joints without fiber, and then exhibited the extremely high safety level.
An optimal condition to improve the adhesion of PTFE/PE lamination of Polytetraﬂuoroethylene (PTFE) untreated and Polyethylene (PE) activated by homogeneous low voltage electron beam irradiation (HLEBI) under each O2 partial pressure in N2 gas atmosphere prior to hot-press was studied. Its adhesive force of PTFE/PE with 0.22 MGy-HLEBI under optimal O2 partial pressure (20000 ppm) in protective N2 atmosphere was 14.6 N/m, which was about 2.2 times higher than that (6.7 N/m) of PTFE/PE with 0.22 MGy-HLEBI under low O2 partial pressure (200 ppm) in N2.