Applied Mechanics and Materials Vols. 446-447

Abstract: The normal mode helical antenna (NMHA) is widely selected on RFID and wireless communication applications and often placed in a dielectric material for protection and miniaurization design. In this paper, the effects of dielectric materials with finite dimension on resonant frequency and impedance characteristics of embedded small NMHA were investigated. Three parameters related to the dielectric material were considered. Significant results were obtained by varying each one of these electrical dielectric parameters. It provides an effective guidance for designers to tune the antenna to desirable complex impedance when surroundded dielectric materials are employed.

Abstract: This paper describes an experimental study on the use of Lamb wave propagation for the integrity assessment of the composite patch system. Composite repairs are performed to the cracked specimen. Two piezoelectric sensors were installed around the composite patch. The piezoelectric sensor response was recorded periodically during the fatigue test. Three types of the damage index based upon the piezoelectric sensor response were selected and calculated to describe the health of the composite patch system. The results show that the damage index based upon the waveform relativity has the best correlations with the expanding process of the damage of the composite patch system.

Abstract: The dosimetry characteristic of Rhizophora Apiculata dye solutions with and without 2, 3, 5 - triphenyltetrazolium chloride (TTC) salt to low dose of gamma irradiation up to 100Gy were investigated spectrometrically. The maximum absorbance was peaking at wavelength of 664nm characteristics of red colour. The dose responses at 664nm wavelength were found decreased with increase of gamma irradiation leading to colour bleaching of the dye solution. The dose sensitivity value of dye solution with TTC lower compared to dye solution without TTC. The colour stability of dyes solutions also have been investigated, the absorbance spectra found no significant change after stored in a dark room at room temperature for 2 weeks.

Abstract: Design and modeling of a CMOS MEMS device using 0.35 µm CMOS technology is used to achieve high sensitivity on mass sensing is presented in this paper. The purpose of this paper is to investigate the effect of increasing beams lengths which support the membrane of the device, on the resonance frequency to achieve high sensitivity. A study on the effect of added mass on the device on natural frequency is also conducted. Mass sensitivity of this device is found to be 153 mHz/ng. At damping ratio of 0.0002, the resonant frequency of the resonator is 19.04 kHz with quality factor 3500.

Abstract: Strapdown Inertial navigation (SINS) is a highly reliable navigation system for short term applications. SINS functions continuously, less hardware failures, renders high speed navigation solutions ranging from 50 Hz to 1000 Hz and exhibits low short-term errors. It provides efficient attitude, angular rate, acceleration, velocity and position solutions. But, the accuracy of SINS solution vitiates with time as the sensor (gyros & accelerometers) errors are integrated through the navigation equations. Average navigation grade SINS are capable of providing effective stand-alone navigation for shorter duration (few minutes) applications Stand-alone SINS capable of providing solutions for applications exceeding 10 minutes duration, are generally highly expensive ($0.1M to $2.0M). To cope with this limitation, a cost effective solution is the integrated navigation system wherein the unboundedly growing errors of SINS are contained with the help of external non-inertial navigation aids like GPS, Celestial Navigation System (CNS), Odometer, Doppler radars etc. The efficient methodology for integrated or multi-sensory navigation is the Federated Kalman Filter (FKF) scheme. In FKF architecture, a reference SINS solution is integrated independently with each of the aiding navigation systems in a bank of local Kalman filters. There are a number of different ways in which the local filter outputs may be combined to produce an integrated navigation solution. The no-reset, fusion-reset, zero-reset, and cascaded versions of federated integration have been used by different researcher and navigators over the years. All different schemes of FKF have certain pros and cons. Fusion-reset method although nearly optimal is less fault tolerant while no-resent scheme renders highly fault tolerant solutions but with sub-optimal solutions and compromised precision. To enhance the fault tolerance ability of fusion-reset scheme of FKF, additional parameters called weighting factors are introduced to tune the contribution of each local filter in the final data fusion. The presented scheme has been found nearly optimal and expressively fault tolerant.

Abstract: In this paper, a security-monitoring system for tiny relics is proposed, which is used to improve the reliability and stability of the museum security system nowadays. This paper analyzed the security-monitoring system of most of the museums in China, and two defects have been discovered. One is that there is almost no security facility which can provide special protection for tiny relics. The other is that there is no effective way to retrieve rare and valuable relics missing in the museum. The security-monitoring system for tiny relics can make up for these weaknesses by integrating two modules, alarm module and position module. Using reed switch as sensitive element, added with chip PT2262, the alarm module can sense micro movement and send position code to central computer wirelessly. Meanwhile, adopting radio frequency identification (RFID) technology for indoor location, position module can provide precise track of moving objects in museums. Combined with traditional security-monitoring, this system can achieve the best protection for tiny relics.

Abstract: In the past two decades, CFRP had been used to strengthen and repair r.c. structures and recently it is also employed to strengthen historical or monumental buildings constituted by masonry structure. However, premature failure due to debonding of the FRP is one of the important issues still to be resolved. Numerous word wide research studies have dealt with the debonding problem in r.c. structures but only a few works were carried out in the masonry structures area. So, the study of the global behaviour of the reinforced masonry element seems to be very useful, both for a congruous design and to verify the strengthening strategy. To this aim, this paper summarizes the debonding phenomena between C-FRP strip and natural calcareous rock brick, employed in our buildings, by means of a testing investigation. Two different kinds of anchorage were designed and employed for the tested samples: standard and reinforced anchorage. The experimental tests carried out on the specimens permits us to compare the effective bond length, with the one obtained by International rules and especially with the Italian CNR-DT200/2004 formulation and to say that the effective bond length dictates by the rules undervalues the experimental data. The data obtained permit us also to know the shear-slip delamination curve useful for the numerical investigation, as well as both the failure mode and the "II mode" fracture energy.

Abstract: Two types of injection molded parts including parts with thin shell feature and parts molded with radial flow pattern are highly susceptible to the warpage. In this research, the warpage performance of a thin and centrally-gated disk was experimentally investigated. The melt pressure-time traces of two different locations inside the mold cavity were monitored by employing piezoelectric transducers. The results indicated that the pressure difference magnitude of melt at two locations along the radial flow path is related to the extent of molded part deformation. Moreover, it was pointed out that the high magnitude of warpage is because of two conflicting actions in the molded part comprising expansion as a result of viscoelastic recovery in the central region, and thermal contraction in the edge region of the thin disk. The molding variables encompassing injection speed, holding pressure, back pressure, mold temperature and screw rotational speed affected the thin disks deformation in order of significance.

Abstract: The vacuum of condenser is an important parameter in the operation of steam turbine, which has a great influence on the safe operation and regulation performance of the turbine. Since the influential factors of vacuum reduction of condenser are fuzzy and uncertain, the improved FAHP is used. By comparing every two of the influential factors, the fuzzy matrix is constructed. The weight index of influential factors of vacuum reduction of condenser in a certain power plant is calculated out quantitatively. The most important influential factor is found out. And there is a verification which exactly identifies the fault of the condenser by using a real instance.

Abstract: In order to achieve automatic detection of the tile flatness and automatic classification of product quality, the top control unit is touch screen, which can download parameters, display result information, control and debug device. Lower machine works as follows, when the tile is transferred to the test platform in the correct position, the laser displacement sensor collects 25 characteristic points information from moving the tile surface, via the A / D module ,the information is converted into digital signals, according to specific flatness algorithm, PLC calculates flatness and achieves tile classification. Practice shows that the accuracy of tile flatness is 0.1mm, detection efficiency is 40 pieces per-minute. The system is suitable the quality control of ceramic tile product.