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Ocean economy plays a crucial role in the strengthening maritime safety industry and in the welfare of human beings. Electric Submersible Pumps (ESP) have been widely used in floating platforms on the sea to provide oil for machines. However, the ESP fault may lead to ocean environment pollution, on the other hand, a timely fault diagnosis of ESP can improve the ocean economy. In order to meet the strict regulations of the ocean economy and environmental protection, the fault diagnosis of ESP system has become more and more popular in many countries. The vibration mechanical models of typical faults have been able to successfully diagnose the faults of ESP. And different types of sensors are used to monitor the vibration signal for the signal analysis and fault diagnosis in the ESP system. Meanwhile, physical sensors would increase the fault diagnosis challenge. Nowadays, the method of neural network for the fault diagnosis of ESP has been applied widely, which can diagnose the fault of an electric pump accurately based on the large database. To reduce the number of sensors and to avoid the large database, in this paper, algorithms are designed based on feature extraction to diagnose the fault of the ESP system. Simulation results show that the algorithms can achieve the prospective objectives superbly.

Spark Plasma Sintering technique was applied to fabricate MoSi2 and MoSi2-bentonite coatings on molybdenum. The phase composition, morphologies and anti-oxidation properties of the coatings at 1500 °C were investigated. Penetrated cracks generated in MoSi2 coating after SPS while the composite coating was crack-free because of the reduction of CTE mismatch. Cracks existed in the silica layer of MoSi2 coating after oxidation while the silica layer of bentonite-containing coating showed dense and crack-free morphologies. Compared with MoSi2, the composite coating possessed thinner Mo5Si3 diffusion layer and silica layer, exhibiting less loss of substrate and coating with improved oxidation resistance.

The origin of low ductility in the hexagonal close-packed (hcp) metal system like Ti is high anisotropic critical resolved shear stress (CRSS) of different slip systems. To reduce the anisotropic deformation is a key for improving the mechanical performance. In the present study, Al alloying shows it can effectively weaken the anisotropic deformation of the hcp system. The relationship between Al alloying and anisotropic deformation was studied by X-ray diffraction, geometric phase analysis, and ab initio calculations. The atomic-scale mechanism behind the isotropic deformation of the Ti-Al alloy was shown that {10−10} prismatic planes were the preferred substitution planes for the Al atoms. The hardening trend of prismatic slip was faster compared to that of basal slip. A high CRSS rate and low CRSS starting point of prismatic slip contributed to the reduction in anisotropic deformation of the Ti-Al alloy. Keywords: Alloying, Anisotropic deformation, Lattice strain, Ab initio calculations

Vibration-based monitoring is one approach used to perform structural condition assessment. By measuring structural response, such as displacement, dynamic characteristics of a structure may be estimated. Often, the primary dynamic responses in civil structures are below 5 Hz, making accurate low frequency measurement critical for successful dynamic characterization. In addition, static deflection measurements are useful for structural capacity and load rating assessments. This paper presents a DC coupled continuous wave radar to accurately detect both dynamic and static displacement. This low-cost radar sensor provides displacement measurements within a compact, wireless unit appropriate for a range of structural monitoring applications. The hardware components and operating mechanism of the radar are introduced and a series of laboratory experiments are presented to assess the performance characteristics of the radar. The laboratory and field experiments investigate the effect of factors such as target distance, motion amplitude, and motion frequency on the radar\'s measurement accuracy. The results demonstrate that the radar is capable of both static and dynamic displacement measurements with sub-millimeter accuracy, making it a promising technology for structural health monitoring.

Amorphous Ti-Cu-Zr-Ni filler foils with low melting point of 1 133 K were synthesized using a melt-spinning method in argon atmosphere. A Ti2AlNb based alloy was brazed at 1 153–1 223 K for 600–3 000 s. The effects of brazing temperature (Tb) and time (tb) on the shear strength of the joints were investigated. The results showed that the joint strength was significantly affected by the reaction layer thickness. The optimum brazing parameters can be determined as follows: Tb=1 173 K, and tb=600 s. The maximum tensile strength of the joint obtained can reach 260 MPa. Furthermore, the activation energy Q and the growth velocity A0 of the reaction layer in the brazed joints were calculated to be 161.742 kJ/mol and 0.213 m2/s, respectively. The growth of the reaction layer (y) could be expressed by the expression: y2 =0.213exp(−19 454/Tb)tb.

A novel high-temperature filler alloy, Co42.5Ti42.5Nb15 (at%) developed with which C f /SiC–Nb joints were successfully obtained at 1553–1613 K for 10 min. The effects of brazing temperature on the microstructure and mechanical properties of the joints were investigated. The results show that the typical C f /SiC and Nb joint consist of C f /SiC composite/(Ti,Nb)C reaction layer/(Ti,Nb) 2 Co layer/Nb[Ti,Co]+(Ti,Nb)Co eutectics with some CoNb 4 Si compounds/Nb substrates. With increasing the brazing temperature, both the thickness of the reaction layers and the content of CoNb 4 Si in the brazing layer increased, whereas the thickness of the brazing layer reduced. The shear strength presented a peak value of 187 MPa from a brazed at 1593 K.

The present study investigated the effect of brazing temperature and holding time on the microstructure and mechanical properties of Ti 2 AlC-copper joints brazed with Ag-Cu filler alloy at 800–900 °C for 10 min and held for different times at 850 °C. The representative structure of the joints was Ti 2 AlC/interaction area in the Ti 2 AlC substrate/brazing layer/diffusion area of the copper substrates/Cu. The brazing layer was composed of Cu-rich phases, AlCu 2 Ti intermetallic compounds and Ag[Cu] solid solutions. With increasing brazing temperature, more filler alloy was infiltrated into the ceramic substrate and reacted with Ti 2 AlC, accelerating the decomposition of Ti 2 AlC and the formation of Ti 3 AlC 2 , TiC and AlCu 2 Ti reaction phases. Moreover, more copper substrate was dissolved into the filler alloy; thus, more Cu-rich phase and AlCu 2 Ti were produced in the brazing layer. Moreover, the width of the brazing layer was reduced, while the widths of both the interaction area and diffusion area increased. As the brazing temperature was increased, the shear joint strength increased and then decreased. By prolonging the holding time, the widths of both the interaction area and the diffusion area were increased, while the width of the brazing layer was held constant at approximately 50 μm. Neither the structure nor the shear strength of the joints was influenced by the holding time. The optimum brazing parameters for joining Ti 2 AlC ceramic to copper with Ag-Cu filler alloy were 850 °C for 40 min. The joints obtained exhibit a maximum shear strength of 203.3 MPa.

For the microaccelerometer, strong axial response and weak cross-axial one are always expected. This paper presents a general analysis about transverse sensitivity of the microaccelerometer. The analysis model is developed, where the influence of response stiffness and damping in different axes, as well as symmetrical decline angles of 3 degrees of freedom system is considered. Moreover, multi-freedom vibration equations based on the analysis model are established. And the equations are solved on condition that damping force is ignored. Finally, the theoretical analysis about transverse sensitivity is accomplished, and some effective methods, which are beneficial to reduce cross disturbance, are provided.

We present a compact displacement measurement system based on single grating and 3×3 coupler, possessing the capability of large range and nanometer precision. With the introduction of 3×3 coupler for phase shift in interference signal, the present scheme has the advantages of simple structure, convenient alignment, and insensitivity to air turbulence, resulting in high robustness . We accordingly developed an efficien t and precision signal processing method for phase demodulation on a digital signal processing, adapting to characteristics of outputs in 3×3 coupler, achieving a high-powered subdivision of the interference phase. It was validated that the phase precision was about 1° even when phase and amplitude errors were added to interference signals in the simulation, which co rresponded to a displacement precision of about 3nm. Keywords : 3×3 coupler; phase measurement; fringe; subdivision algorithm 1. INTRODUCTION As one of technologies that can realize displacement measurement with nanometer resolution, grating interferometry possesses the advantages of small volume, low cost, simple configuration and easy instrumentation. Compared to the traditional laser interferometer, it provides measurement benchmarks with a real object and has a relatively low requirement for environmental conditions

A novel low-noise front-end electronics was proposed for detection of light signals with intensity about 10 μW and frequency above 2.7 MHz. The direct current (DC) power supply, pre-amplifier and main-amplifier were first designed, simulated and then realized. Small-size components were used to make the power supply small, and the pre-amplifier and main-amplifier were the least capacitors to avoid the phase shift of the signals. The performance of the developed front-end electronics was verified in cross-grating diffraction experiments. The results indicated that the output peak-topeak noise of the ±5 V DC power supply was about 2 mV, and the total output current was 1.25 A. The signal-to-noise ratio (SNR) of the output signal of the pre-amplifier was about 50 dB, and it increased to nearly 60 dB after the mainamplifier, which means this front-end electronics was especially suitable for using in the phase-sensitive and integrated precision measurement systems.

The ability to accurately measure bridge deflections is an important aspect of bridge monitoring and maintenance, both in the US and internationally. Static deck deflections are used to provide load ratings while dynamic deflection measurements may be used to track changes in the dynamic behavior of the bridge due to environmental, loading, and condition changes. Directly measuring bridge deflection has proven challenging, requiring either a fixed reference point or the use of non-contact laser sensors. This presentation introduces wireless, continuous wave radar sensors developed for bridge monitoring applications. The small, bridge-mounted sensors provide a practical and low-cost solution for a range of measurement conditions. As the bridge moves, the radars send a continuous wave that is reflected by a stationary target (either the ground below or a fixed transponder, depending on the application). The reflected signal contains the information necessary to extract the bridge motion. While the theoretical operation is straightforward, there are challenges associated with signal demodulation and data processing in the presence of noise due to interference or long detection ranges. Characterization of the static and dynamic performance of the radar is presented, as well as guidelines for their practical application. The audience of this presentation will be both researchers and practitioners working to improve bridge inspection and monitoring practices. Specifically, the audience will learn about a novel technology to improve bridge testing, gain an understanding of the advantages and challenges of applying radar technology to structural monitoring, and be presented with strategies for achieving a network of distributed radar sensors to capture bridge responses.

Doppler radar has the capability to remotely monitor human respiration. However, in real applications random body movements during measurement will cause drift of “DC” level in the experiment results. Also, the dc level will shift slowly with the temperature change of the radar circuit. Those DC drifts will cause inaccurate measurement results. To solve the dc drift issue during the experiments, an automatic DC-correction algorithm is developed. Experiment results show that this algorithm eliminates undesirable DC drifts and offset while recovering useful information of the original respiration signal. It is able to provide reliable respiration measurement even if there are large body movements that otherwise overwhelm the desired signal.

This paper presents a Doppler radar sensor system with camera-aided random body movement cancellation (RBMC) techniques for noncontact vital sign detection. The camera measures the subject's random body motion that is provided for the radar system to perform RBMC and extract the uniform vital sign signals of respiration and heartbeat. Three RBMC strategies are proposed: 1) phase compensation at radar RF front-end, 2) phase compensation for baseband complex signals, and 3) movement cancellation for demodulated signals. Both theoretical analysis and radar simulation have been carried out to validate the proposed RBMC techniques. An experiment was carried out to measure a subject person who was breathing normally but randomly moving his body back and forth. The experimental result reveals that the proposed radar system is effective for RBMC.

A continuous wave (CW) radar sensor system with active transponders is designed for Structural Health Monitoring (SHM) to accurately measure the structures' vibration while rejecting clutters reflected from the surrounding environment. The radar sensor, designed with a coherent heterodyne architecture, transmits a single-tone 2.4 GHz signal and receives a returning signal at 3.3 GHz, thus rejecting the backscattered clutters at 2.4 GHz. The active transponder was designed to convert the received 2.4 GHz signal up to 3.3 GHz and transmits a 900 MHz reference to synchronize the radar sensor. The proposed radar with active transponders was tested in lab environment to successfully capture vibration movements from 4.1 m with SNR over 35 dB. Experiments also showed that the radar sensor can isolate the target motion from the interferences from surrounding shaking bodies and sinusoidal phantom motions.

Magnetorheological (MR) disk-type isolating dampers are the semi-active control devices that use MR fluids to produce controllable squeezing force. In this paper, the analytical endeavor into the fluid dynamic modeling of an MR isolating damper is reported. The velocity and pressure distribution of an MR fluid operating in an axisymmetric squeeze model are analytically solved using a biviscosity constitutive model. Analytical solutions for the flow behavior of MR fluid flowing through the parallel channel are obtained. The equation for the squeezing force is derived to provide the theoretical foundation for the design of the isolating damper. The result shows that with the increase of the applied magnetic field strength, the squeezing force is increased.

A novel 2-D optical excited self-resonant microaccelerometer is presented. And its optical characteristics are discussed in theory. Based on genetic algorithm, the thickness of the polysilicon microbeam and the height of the vacuum cavity are optimized to obtain the optimum of light transmissivity.