Shift invariant sparse coding ensemble and its application in rolling bearing fault diagnosis

This paper proposes an automatic diagnostic scheme without manual feature extraction or signal pre-processing. It directly handles the original data from sensors and determines the condition of the rolling bearing. With proper application of the new technique of shift invariant sparse coding (SISC), it is much easier to recognize the fault. Yet, this SISC, though being a powerful machine learning algorithm to train and test the original signals, is quite demanding computationally. Therefore, this paper proposes a highly efficient SISC which has been proved by experiments to be capable of representing signals better and making converges faster. For better performance, the AdaBoost algorithm is also combined with SISC classifier. Validated by the fault diagnosis of bearings and compared with other methods, this algorithm has higher accuracy rate and is more robust to load as well as to certain variation of speed

Novel blue-emitting KBaGdSi2O7:Eu2+ phosphor used for near-UV white-light LED

Novel blue-emitting KBaGdSi2O7:Eu2+ phosphors were designed and synthesized through solid-state reaction method. The structural properties, concentration, and temperature-dependent luminescence behaviors of these phosphors were investigated in detail in this paper. Studies revealed that KBaGdSi2O7:Eu2+ phosphors have an intense absorption in the broad wavelength ranging from 250 to 400 nm that is suitable for the commercial near-UV LED, and give out intense blue light peaked at 475 nm with a full-width half-maximum of 75 nm. The crystallographic information of KBaGdSi2O7 phase is revealed from XRD pattern by Rietveld refinement. Band gap is derived to be 3.93 eV through diffuse reflection spectra through Kubelka Munk function. The concentration quenching mechanism is identified as the dipole–dipole interaction. Moreover, the thermal quenching experiment was also conducted and the activation energy is calculated as 0.3069 eV, which indicates this novel KBaGdSi2O7:Eu2+ phosphor has good thermal stability. These properties exhibit its potential commercial application for near-UV white-light LEDs (w-LEDs)

Provenance Discrimination of Siliciclastic Sediments in the Western Sea of Japan over the Past 30 kyr: Evidence from Major, Trace Elements, and Pb Isotopes

AbstractThe Sea of Japan (JS), a unique marginal sea without any large river influxes in the western Pacific, provides ample information about the evolution of sea level, East Asian monsoons (EAM), sea ice activity, and ocean currents in geological time. However, insufficient investigation in the western JS limits our knowledge of East Asian climate change. This study utilizes major and trace elements and Pb isotopes of fine siliciclastic components (<63 μm) of core LV53-18-2 and determines the provenances using statistical methods and discrimination diagrams. The results show that the terrigenous debris of LV53-18-2 was mainly composed of aeolian dust from northeast China, ice-rafted debris (IRD), and volcanic materials from the Far East coast over the last 30 kyr. During the late last glacial period, sea ice activity carried weakly weathered IRD to the study area. Meanwhile, the strengthened East Asian winter monsoon (EAWM) brought dust from northeast China to the study site owing to the cold climate and enlarged sandy land. During the late last deglacial period to early Holocene (15-8 kyr), ascending boreal summer insolation drove the intense melting of sea ice. This led to the deposition of large amounts of weakly weathered IRD and remarkably influenced the chemical composition of the core. After 8 kyr, the global sea level rose to -15 m below the modern sea level and opened the Tatar Strait. Consequently, freshwater supplied by the Amur River entered the JS and gave birth to the Liman Cold Current (LCC), which transported more mafic materials from the Kema terrane upstream

Effect of thermo-mechanical treatment on mechanical and elastic properties of Ti–36Nb–5Zr alloy

The evolutions of phase constitutions and mechanical properties of a β-phaseTi–36Nb–5Zr (wt%) alloy during thermo-mechanical treatment were investigated. The alloy consisted of dual (β+α″) phase and exhibited a double yielding phenomenon in solution treated state. After cold rolling and subsequent annealing at 698 K for 20 min, an excellent combination of high strength (833 MPa) and low modulus (46 GPa) was obtained. The high strength can be attributed to high density of dislocations, nanosized α phase and grain refinement. On the other hand, the low Young׳s modulus originates from the suppression of chemical stabilization of β phase during annealing, which guarantees the low β-phase stability. Furthermore, the single-crystal elastic constants of the annealed Ti–36Nb–5Zr alloy were extracted from polycrystalline alloy using an in-situ synchrotron X-ray technique. The results indicated that the low shear modulus C44 contributes to the low Young׳s modulus for the Ti–36Nb–5Zr alloy, suggesting that reducing C44 through thermo-mechanical treatment might be an efficient approach to realize low Young׳s modulus in β-phase Ti alloys. The results achieved in this study could be helpful to elucidate the origin of low modulus and sheds light on developing novel biomedical Ti alloys with both low modulus and high strength

Carbon Footprint Constrained Profit Maximization of Table Grapes Cold Chain

Low-carbon production is one of the dominating issues in the sustainable development of the food industry with high energy consumption, especially in the table grapes cold chain. The aim of this paper is to propose a profit maximization strategy of table grapes cold chain by integrating the carbon footprint to improve the low-carbon production and sustainability of the cold chain system. The carbon footprint was evaluated by life cycle assessment (LCA) in entire cold chain system of table grapes, and the economic order quantity (EOQ) model was used to develop the profit maximization model with minimal carbon footprint and to maintain the optimal balance between stock and cost. The profit optimization performance, the sensitivity performance and the influencing factors of the decay rate, the carbon emission price, and the distance and carbon emission coefficient in refrigerated transport were analyzed according to the profit maximization model and the inventory data in actual cold chain investigated. The sensitivity performance analysis illustrated that the selling price had the highest sensitivity, and the carbon emission coefficient in storage had the lowest sensitivity. The comprehensive analysis results indicated that there is an optimal combination point between the economy and environment in actual cold chain, which not only reduced the carbon emission, but also had minimal impact on the profit in cold chain. The enterprises should integrate the carbon footprint cost into the profit maximization once the carbon emission tax is levied. The proposed strategy of the profit maximization with carbon footprint constraint is also suitable for improving profit maximization of other low-carbon supply chain applications

Simulation of optical behavior of YAG:Ce3+@SiO2 phosphor used for chip scale packages WLED

YAG:Ce3+ yellow phosphor are particularly used luminescent materials to produce white light in phosphor-converted white LED (pc-WLED). Surface coating of YAG phosphor is the main concern for desired optical performance of the phosphors. Many scholars conducted various experimental analysis on the surface coating of phosphors to improve yellow emission, but the theoretical explanation by which phosphor coating could help improving light efficiency has not yet been studied. In this paper, based on Mie theory, the optical constants such as scattering coefficient, absorption coefficient and asymmetry parameter of YAG:Ce3+ phosphor and YAG@SiO2 (YAG:Ce3+ phosphor surface coated with nano-SiO2 layer) were calculated. An optical configuration of chip scale packages (CSP) WLED was constructed by coupling YAG:Ce3+ or YAG@SiO2 phosphors with a LED laser. Based on the optical parameters calculated by Mie theory, the luminescent properties of YAG:Ce3+ and YAG@SiO2 WLED were simulated by Monte Carlo method. The results showed that a thin SiO2 coating layer on YAG phosphor result in an overall increase in luminous performances compared with original YAG WLED. The absorption coefficient of phosphor is the main concern affecting the light emission in WLED. Due to the fact that YAG@SiO2 possess higher 460 nm absorption coefficient , it could absorb more blue light than YAG, thereby it has a 1.2% higher conversion efficiency than YAG, finally the enhanced luminous efficiency of YAG@SiO2 WLED is obtained. The results obtained in this work provides a potential method in future WLED packaging designing

MS-BWME: A Wireless Real-Time Monitoring System for Brine Well Mining Equipment

This paper describes a wireless real-time monitoring system (MS-BWME) to monitor the running state of pumps equipment in brine well mining and prevent potential failures that may produce unexpected interruptions with severe consequences. MS-BWME consists of two units: the ZigBee Wireless Sensors Network (WSN) unit and the real-time remote monitoring unit. MS-BWME was implemented and tested in sampled brine wells mining in Qinghai Province and four kinds of indicators were selected to evaluate the performance of the MS-BWME, i.e., sensor calibration, the system’s real-time data reception, Received Signal Strength Indicator (RSSI) and sensor node lifetime. The results show that MS-BWME can accurately judge the running state of the pump equipment by acquiring and transmitting the real-time voltage and electric current data of the equipment from the spot and provide real-time decision support aid to help workers overhaul the equipment in a timely manner and resolve failures that might produce unexpected production down-time. The MS-BWME can also be extended to a wide range of equipment monitoring applications

Tunable luminescence and energy transfer from Ce3+ to Dy3+ in Ca3Al2O6 host matrix prepared via a facile sol-gel process

Herein, Ce3+ and Ce3+/Dy3+ co-doped Ca3Al2O6 phosphors have been designed and synthesized via a facile citrate-based sol-gel technique, and their structural, photoluminescence properties and energy transfer phenomenon were investigated comprehensively. The XRD analysis indicated that pure Ca3Al2O6 phase can be synthesized at low temperature (1000 °C) for merely 2 h. The photoluminescence spectra showed the dominant emission of Ce3+ singly doped phosphors is located in the blue region even at low Ce3+ doping level, which indeed favors the energy transfer from Ce3+ to other luminescent centers. When Dy3+ is co-doped into Ca3Al2O6:Ce3+ phosphors, the remarkable sensitizing effect of Ce3+ on Dy3+ is validated by comparatively analyzing the excitation, emission spectra and average lifetimes of the series of samples. Through the concentration quenching theory, the critical distance between Ce3+ and Dy3+ is calculated to be 13.50 Å. Furthermore, the energy transfer mechanism between them is most likely ascribed to electric dipole-dipole interaction. In virtue of the variation of the emission intensities of Ce3+ and Dy3+, the emitting colors of Ca3Al2O6:Ce3+, Dy3+ phosphors can realize tunable luminescence from deep blue to bluish-white region through controlling the Dy3+ content. Based on these analysis, Ca3Al2O6:Ce3+, Dy3+ phosphors could potentially be applied as a single-phase color-tunable phosphors pumped by near-ultraviolet (n-UV) radiation