Search

This Letter presents a flexible wire-driven linear actuator using a bio-inspired sealing method that allows to replace a rigid rod by a flexible one and reduce the size of a robot link containing pneumatic or hydraulic linear actuators. Conventional pneumatic or hydraulic linear actuator sealing hinders the use of flexible wires as actuator rods. In contrast, the proposed tube sealing resembles a long balloon wrapping around the wire and stretching or contracting with the wire rod motion. Therefore, the wire is separated from the chamber and prevents fluid leakage through the flexible wire rod. This sealing method is inspired by earthworm which has slippery skin and stretching or contracting motion. The authors fabricated a prototype wire rod pneumatic linear actuator using the proposed tube seal and conducted leakage tests. In addition, the authors evaluated linearity between the input pressure and output force to determine the linear actuator performance.

Phase transformation behavior of the quasicrystalline icosahedral phase (I-phase) and mechanical properties in a Ti 41.5 Zr 41.5 Ni 17 alloy have been investigated using suction-casted bulk samples with various sample sizes (ϕ = 2, 3 and 5 mm). For 2 and 3 mm diameter rod samples, micrometer size dendritic β-(Ti,Zr) phases are precipitated in the matrix and continuously I-phases are developed in the vicinity of the primary β-(Ti,Zr) phases. With further increase of the sample size (i.e. decrease of cooling rate; ϕ = 5 mm), the length scale and volume fraction of primary β-(Ti,Zr) dendritic phase are continuously increased and the constitution of matrix phase is changed from I-phase to eutectic lamella composed of bcc β-(Ti,Zr) and hcp C14 Laves phases. The characterization of mechanical properties was carried out by compression and microhardness tests at room temperature. Depending on the selection, size and volume fraction of constituent phases, the values of hardness and compressive fracture strength are varied. The fracture surface morphologies of failed samples exhibit cleavage and quasi-cleavage patterns revealing the typical brittle failure characteristics.

We fabricated the field effect transistor using single crystalline ZnO nanowires synthesized by a conventional thermal evaporation method and investigated their basic properties under the various conditions such as ultraviolet irradiation, reducing gas and electrolyte. The typical carrier concentration and mobility of the single crystalline ZnO nanowire with a diameter of 100 nm and length of 5 um were and , respectively. The current of ZnO nanowire under ultraviolet irradiation significantly increased about 400 times higher as compared to in the darkness. In addition, the ZnO nanowire showed typical sensing characteristics for and CO due to well-known surface reactions and typical current-voltage characteristics under the 0.1 M NaCl electrolyte.

A bio-detection method and devices based on RF electric signals and MEMS are proposed and demonstrated by a label free method. We have fabricated a transmission line, an inductive device, and a capacitive device with silicon-based MEMS technology. Main issues are fabrication of devices by MEMS technology, surface modification from hydrophobic to hydrophilic of a benzocyclobutene (BCB) layer by plasma radiation and RF signal measurement before and after bio-processing. The devices made by MEMS technology consist of a BCB polymer and Cu metal patterns on a silicon substrate. Glucose oxidase (GOx) and poly dimethyldiallyl ammonium chloride (PDAC) are used as a biomolecule target and probe. The measured output of power loss is 0.8 dB at 1.9 GHz, and its value is pretty distinguishable from the noise level. From the above-mentioned results, it is clear that the proposed RF method and designs are very effective and powerful as a label free detection system.

Comparative investigations of the effects of steel-making practices on impact and fracture toughness were studied. From these examinations, impact and fracture toughness of the steels by vacuum carbon deoxidation (VCD) offered the required values; however, those of the steels by modified VCD and silicon-killing practices were secure. The fracture toughness (KIC) was significantly improved by the silicon-killing and the modified VCD. These resulted from the fineness of austenitic grain size and reduction of sulphidic inclusion. It was observed that the grain size of steels by modified VCD and silicon-killing practices was 20 μm, while that of steel by VCD was 50 μm. The sulphidic inclusion contents were reduced in the steels by modified VCD and silicon-killing practices. Furthermore, the effects of cooling rates from austenitizing temperature on the impact toughness in the steel by VCD were also investigated. The impact toughness of the steel by VCD was closely related to the cooling rate. To obtain the secure impact toughness in the steel by VCD, it seems that the recommended minimum cooling rate from the austenitizing temperature should be 15°C min−1.

Hydrogen attack and the associated change in mechanical properties in a 3Cr–1Mo–0.25V steel subjected to a simulated welding thermal treatment were investigated to show the influence of welding conditions on the heat affected zone. The maximum peak temperature reached in the simulated welding process affected the microstructure, which in turn is related to the occurrence of different quantities of methane bubbles.

In this work, in order to realize the possible defects at the cable joint interface, four different types of artificial defects are provided such as conducting, insulating substances, void and scratches. The analysis related to the PD patterns has been performed by means of Phase Resolved Partial Discharge Analysis (PRPDA) and Chaotic Analysis of Partial Discharge (CAPD) as well. The results show that it could be pointed out that each defect has shown particular characteristics in its pattern respectively and that the nature of the defect causing partial discharge could be identified more distinctively when the CAPD is combined with a conventional statistical method, PRPDA.

The polyimide thin films, which are synthesized with pyromellitic dianhydride (PMDA) and 4,4'-diaminodiphenyl ether (DDE), are fabricated by the vapor deposition polymerized method of dry processes. In order to analyze the characteristics required for inter-layer insulation films of semiconductor devices, the molecular structure and uniformity, the variation of the internal composition element, the permeation depth of the upper electrode, and the breakdown strength are experimentally investigated.

To understand the effect of crosslinking in polyethylene on the water tree propagation, low-density polyethylene (LDPE) and Co/sup 60/ gamma -ray irradiated polyethylene were used for water treeing tests. Injection molded samples were made of LDPE using the CNRS laboratory model, and some of them were irradiated at different dose rates to produce crosslinking. The aged specimens were subjected to microscopic investigation, using scanning electron microscopy to study the morphology of the fractured surface and polarizing microscopy to study the structure of spherulite. It appears that the different structures found in the irradiated and nonirradiated materials polyethylene could account for the different water tree propagation in these materials. >

The fabrication of /spl beta/"-alumina films, as a thermoelectric material, by thermal plasma processing based on the forced constrictive type reactor was investigated. Under both atmospheric and low pressure, /spl beta/"-alumina films were successfully synthesized from mixed powder of /spl alpha/-Al/sub 2/O/sub 3/, Na/sub 2/CO/sub 3/ and MgO. The jet power and substrate position strongly affect the properties of plasma processed /spl beta/"-alumina, which was found to be correlated with jet temperature. For both pressures, the films show good thermoelectric properties.