In this study, we fabricated and investigated the polymer-based cylindrical flow sensor for two-dimensional (2D) detection. The flow sensor was the drag force type flowmeter which was fabricated with ecoflex. It had CNT/PDMS as the piezoresistive material and a cylindrical shape to measure the 2D flow. It also had impact resistance and ease of fabrication due to its polymer-based sensor. At first, two piezoresistive parts were applied to evaluate detection properties. Forces from various direction were applied. Results showed its potential as a sensing device. Following this, the final flow sensor was fabricated with four piezoresistive parts and its sensitivity was measured in the air flow from 0 to 30 m/s. Resistance changes were measured while rotating the sensor. Outputs showed a form of sine waves. Data were repeatedly collected under various conditions. The direction and air flow rate were then determined. To check physical impact resistance, a sudden high air flow rate with 100m/s was applied to the sensor and a stable output was obtained. These results suggest that such ecoflex-based cylindrical flow sensor can be used as a 2D flow rate sensor.
With recent development of 3D printing technology, its applications to the bio-industry are increasing. Many research studies are being done for manufacturing personalized tablets through this technology in the pharmaceutical process. In this study, to control the dissolution rate of tablets, a lattice structure was inserted into the tablet and the dissolution rate was compared. The tablet proposed in this study can be manufactured by the FDM method, adopting a lattice structure with a large surface area-to-volume ratio. Tablets containing various lattice structures were fabricated using water-soluble PVA filaments and dissolution experiments were conducted in water at 37oC. As a result, it was confirmed that the specific surface area and the mass loss rate were proportional to both the 3D lattice structure and the monolith structure. Among different structures, the diamond structure had the most active dissolution.
Nowadays in building construction field, workers become aged and avoid dirty, difficult, and dangerous work. Above all, a person who is in charge of beam assembling work in high and narrow space just relies on safety belt. So these workers should be highly trained. This paper deals with a new locomotion robot that can take this in charge, which will be able to provide less labor costs, less time to build a building and safer environments for workers. The geometric features of steel structure in building construction were carefully analyzed and developed a locomotion mechanism optimized to it. The robot was designed to be rugged, strong, and fast rather than having excessive mobility. Feasibility of the developed robot was verified through experiments.
Automatic grease lubricator is equipment that provides adequate amount of fresh grease constantly to the shaft and the bearings of machines. It minimizes the friction heat and reduces the friction loss of machines to the least. This research is to develop automatic grease lubricator by gear driven mechanism with controlled operation time. The ultimate design of this equipment is to lubricate an adequate amount of grease by a simple switch clicking according to the advanced set cycle. The backlash of the gear was minimized to increase the output power. To increase the power of gear mechanism, the binding frequency and the thickness of the coil were changed. To control the rotating cycles of the main shaft according to its set numbers, different resistance and chips were used to design the circuit to controls electrical signals with pulse. The body of the lubricator was analyzed by stress analysis with different constructed angle. The stress analysis for differing loading pressures applied to the exterior body of grease lubricator due to the setup angle, was found that the maximum stress was distributed over the outlet part where the grease lubricator suddenly narrowed contracts. Digital mock-up was analyzed and the rapid prototyping(RP) trial products were tested with PCB circuit and grease. The evaluation of the outlet capacity for RP trial products was conducted, because the friction caused by the outlet on the wall surface was an important factor in the operation of the equipment. Finally, the finishing process was applied to decrease the roughness of the surface to a comparable level and was able to test the performance examination for the product.