A combined direct and inverse iterative design method was developed for the hydraulic of centrifugal pump impellers. This is based on fluid continuity motion equations solves meridional velocity taking into account effects blade shape flow. The drawn by point-by-point integration with thickening smoothing using conformal mapping. Two examples designed are compared to results traditional significantly different distributions three-dimensional shapes. Numerical simulations tests show that...

In this study, we designed and manufactured an ideal electromigration testing device for soldering joints to solve the reliability problems caused by temperature current density changes in processes of micro solder joints. We analyzed effects on β-Sn (single-crystal grain) Sn2.5Ag0.7Cu0.1RE/Cu joints, relationship between grain orientation interfacial IMC (intermetallic compound) growth mechanical properties The results showed that angle θ c-axis direction joint gradually decreased 8.2° when...

To solve the electromigration problem of micro-electronic connection solder joints, an ideal tester was designed, and thickness intermetallic compounds (IMCs), average void diameter, grain orientation, failure, shear strength, fracture path Sn2.5Ag0.7Cu0.1RE0.05Ni-GNSs/Cu joints under constant-temperature were studied. The results indicate that show evidence typical polarity in asymmetric growth interfacial IMCs on anode cathode sides conditions a current density ≥7 × 103 A/cm2 included...

Industrial motors have been widely used in various fields such as power generation, mining, and manufacturing. Various motor faults time-consuming maintenance processes will lead to serious economic losses this context. Different sensing technologies, including acceleration, acoustic, current can be useful condition monitoring, defect detection, diagnosis. Regarding data analytics, Machine Learning (ML) Deep (DL) techniques increasingly investigated, because of their promising capabilities...

Due to the fluctuation and randomness of photovoltaic power over time, accurate reliable ultra-short-term forecasting is significant for real-time dispatch frequency regulation grids. In this article, improved BO-LSTM frame considering correlation mapping proposed. Firstly, features are extracted resolved according series segments. Then, established model adjusted based on above in separate segment, results deterministic obtained. Furthermore, order obtain performance, time-correlation...

Transient thermochromic liquid crystal thermography, a laser-Doppler velocimeter, and pressure transducers have been used to measure the local heat transfer, velocity, wall static-pressure distributions, respectively, in rotating two-pass square duct with 90-deg ribs detached from leading trailing walls. The were cross-section their detached-distance/height ratio was 0.38. rib-height/duct-height pitch/rib-height 0.136 10, respectively. Reynolds number 1×104 rotation ranged 0 0.2. Results are...

With the development of modern industry, rotary lip seals are applied to more complex working conditions. For with larger or smaller radial force and incomplete motion such as robot joint seals, it has been found that traditional reverse pumping theory a certain scope application. Therefore, in this study, mixed lubrication model based on deterministic surface microdeformation is proposed calculate tangent deformation asperities without presetting effect then assess behavior. The force,...

Aiming at the thermomigration problem caused by large temperature gradient (TG) of micro-soldering joints, a constant device with control function was designed and manufactured. This paper studied polarity phenomenon, crystallographic characteristics, interfacial intermetallic compound (IMC) growth kinetics Ni-GNSs reinforced Sn2.5Ag0.7Cu0.1RE/Cu solder joints under thermomigration. The results indicate that exhibited significant phenomenon conditions TG ≥ 1000 °C/cm θ ≤ 43.5° between c-axis...

Abstract The film thickness varied because of the swing tilting‐pad thrust bearing, which introduced squeezing effect in start‐up and shutdown periods. interface slippage might occur between water pad surface, effects polarity surface energy material. To study performance water‐lubrication bearing during shutdown, a transient model considering was established. on film‐thickness distribution, nondimensional minimum thickness, circumferential angle, friction torque were studied. theoretical...

Head-in-pillow (HiP) is a BGA defect which happens when solder balls and paste can't contact well during reflow soldering. Package warpage was one of the major reasons for HiP formation. In this paper, package measured simulated. It found that sensitive to thickness inside chips. A FEM method considering viscoelastic property mold compound introduced simulate warpage. The CTE mismatch contributes more than 90% value reflowing at peak temperature. measure threshold, smallest may lead HiP....

Touchdown bearing (TDB) is one of the key elements in active magnetic bearings (AMBs). When fails or exposed to an overload, touchdown events will occur. According ISO 14839, three typical orbit responses (pendulum vibration, combined rub and bouncing, full rub) can be detected events. The magnitude dynamic forces between rotor TDBs has been considered as indicator identify these responses. However, contact may not easy measure with precision. instantaneous frequency vibration another...

In respect to the influence of ultra wide-band electromagnetic pulse on unmanned aerial data link system, an effect test was carried out, law obtained, and protection suggestions were given. First, intensities radiation field at different distances measured. Then corresponding relationship between environment fault phenomenon system obtained under intensities, repetition frequencies states. Experimental show that as hardcore vehicle, is susceptible strong interference. Front door coupling...

Electromigration is one of the most important research issues affecting reliability solder joints. Current-induced Joule heating affects electromigration behavior Solder joints with different cross-sectional areas were designed to obtain properties. The effects interfacial intermetallic compound (IMC) and mechanical properties Sn58Bi/Cu studied for results showed that as area increased, joint increased. anode IMC thickness thickened transformed into a planar shape. Bi migrated region form...

Low-frequency ultra-wideband synthetic aperture radar is a promising technology for landmine detection.According to the scattering characteristics of body-of-revolution (BOR) along with azimuth angles, discriminator based on Bayesian decision rule proposed, which uses sequential features, i.e., double-hump distance.First, algorithm estimates target scatterings in all angles regions interest.Second, aspect features are extracted by sparse time-frequency representation.Third, distributions...

Box girder is an important bearing and force transmitting component in the gondola car body; rationality of its structure directly affects life whole body. In order to solve disadvantage traditional box optimization method, which mainly depends on design experience, combined method orthogonal experimental genetic algorithm-back propagation (GA-BP) algorithm used for structural bolster beam this paper. Nine groups parameters were established by experiment, can give typical samples GA-BP...

The paper researches a novel engineering application of Lipschitz exponent function and harmonic wavelet for detecting tool condition. Tool wear affects often the quality grade products is gradually formed during cutting process. Meanwhile, since noise very strong, we think belongs to weak singularity signals in strong noise. It difficult obtain reliable worn result by raw sampled data. We propose analysis with data processing new concept function. method can be quantitative condition make...