Based on the statics theory, a novel and feasible twice-suspended-mass method(TSMM) was proposed to deal with the seldom-studied issue of fault diagnosis for damping springs of large vibrating screen(LVS). With the st...Based on the statics theory, a novel and feasible twice-suspended-mass method(TSMM) was proposed to deal with the seldom-studied issue of fault diagnosis for damping springs of large vibrating screen(LVS). With the static balance characteristic of the screen body/surface as well as the deformation compatibility relation of springs considered, static model of the screen surface under a certain load was established to calculate compression deformation of each spring. Accuracy of the model was validated by both an experiment based on the suspended mass method and the properties of the 3D deformation space in a numerical simulation. Furthermore, by adopting the Taylor formula and the control variate method, quantitative relationship between the change of damping spring deformation and the change of spring stiffness, defined as the deformation sensitive coefficient(DSC), was derived mathematically, from which principle of the TSMM for spring fault diagnosis is clarified. In the end, an experiment was carried out and results show that the TSMM is applicable for diagnosing the fault of single spring in a LVS.展开更多
Printing techniques hold great potential in the manufacture of electronics such as sensors,micro-supercapacitors,and flexible electronics.However,developing large-scale functional conductive inks with appropriate rheo...Printing techniques hold great potential in the manufacture of electronics such as sensors,micro-supercapacitors,and flexible electronics.However,developing large-scale functional conductive inks with appropriate rheological properties and active components still remains a challenge.Herein,through optimizing the formulations of ink,iron single sites supported N-doped carbon black(Fe_(1)-NC)inks can serve as both conductive electrodes and high-reactive catalysts to realize convenient glucose detection,which pronouncedly reduces the dosage of enzyme and simplifies the sensors preparation.In detail,utilizing in-situ pyrolysis method,Fe_(1)-NC single-atom catalysts(SACs)are prepared in bulk(dekagram-level).The batched Fe_(1)-NC SACs materials can be uniformly mixed with modulated ink to realize the screen printing with high resolution and uniformity.Also,the whole scalable preparation and ink-functional process can be extended to various metals(including Co,Ni,Cu,and Mn).The introduction of highly active Fe_(1)-NC sites reduces the amount of enzyme used in glucose detection by at least 50%,contributing to the cost reduction of sensors.The strategy in harnessing the SACs onto the carbon inks thus provides a broad prospect for the low-cost and large-scale printing of sensitive sensing devices.展开更多
Demand for large vibrating screen is huge in the mineral processing industry. As bending and random vibration are not considered in a traditional design method for beam structures of a large vibrating screen, fatigue ...Demand for large vibrating screen is huge in the mineral processing industry. As bending and random vibration are not considered in a traditional design method for beam structures of a large vibrating screen, fatigue damage occurs frequently to affect the screening performance. This work aims to conduct a systematic mechanics analysis of the beam structures and improve the design method. Total motion of a beam structure in screening process can be decomposed into the traditional followed rigid translation(FRT), bending vibration(BV) and axial linear-distributed random rigid translation(ALRRT) excited by the side-plates. When treated as a generalized single-degree-of-freedom(SDOF) elastic system analytically, the BV can be solved by the Rayleigh's method. Stochastic analysis for random process is conducted for the detailed ALRRT calculation. Expressions for the mechanics property, namely, the shearing force and bending-moment with respect to BV and ALRRT, are derived, respectively. Experimental and numerical investigations demonstrate that the largest BV exists at the beam center and can be nearly ignored in comparison with the FRT during a simplified engineering design. With the BV and FRT considered, the mechanics property accords well with the practical situation with the maximum error of 6.33%, which is less than that obtained by traditional method.展开更多
基金Project(20120095110001)supported by the PhD Programs Foundation of Ministry of Education of ChinaProject(51134022,51221462)supported by the National Natural Science Foundation of China+1 种基金Project(CXZZ13_0927)supported by Research and Innovation Program for College Graduates of Jiangsu Province,ChinaProject(2013DXS03)supported by the Fundamental Research Funds for Central Universities of China
文摘Based on the statics theory, a novel and feasible twice-suspended-mass method(TSMM) was proposed to deal with the seldom-studied issue of fault diagnosis for damping springs of large vibrating screen(LVS). With the static balance characteristic of the screen body/surface as well as the deformation compatibility relation of springs considered, static model of the screen surface under a certain load was established to calculate compression deformation of each spring. Accuracy of the model was validated by both an experiment based on the suspended mass method and the properties of the 3D deformation space in a numerical simulation. Furthermore, by adopting the Taylor formula and the control variate method, quantitative relationship between the change of damping spring deformation and the change of spring stiffness, defined as the deformation sensitive coefficient(DSC), was derived mathematically, from which principle of the TSMM for spring fault diagnosis is clarified. In the end, an experiment was carried out and results show that the TSMM is applicable for diagnosing the fault of single spring in a LVS.
基金supported by the Ministry of Science and Technology of China(No.2021YFA1500404)the National Natural Science Foundation of China(Nos.92261105 and 22221003)+1 种基金USTC Research Funds of the Double First-Class Initiative(No.YD9990002022)the Shanghai Sailing Program(No.22YF1413400).
文摘Printing techniques hold great potential in the manufacture of electronics such as sensors,micro-supercapacitors,and flexible electronics.However,developing large-scale functional conductive inks with appropriate rheological properties and active components still remains a challenge.Herein,through optimizing the formulations of ink,iron single sites supported N-doped carbon black(Fe_(1)-NC)inks can serve as both conductive electrodes and high-reactive catalysts to realize convenient glucose detection,which pronouncedly reduces the dosage of enzyme and simplifies the sensors preparation.In detail,utilizing in-situ pyrolysis method,Fe_(1)-NC single-atom catalysts(SACs)are prepared in bulk(dekagram-level).The batched Fe_(1)-NC SACs materials can be uniformly mixed with modulated ink to realize the screen printing with high resolution and uniformity.Also,the whole scalable preparation and ink-functional process can be extended to various metals(including Co,Ni,Cu,and Mn).The introduction of highly active Fe_(1)-NC sites reduces the amount of enzyme used in glucose detection by at least 50%,contributing to the cost reduction of sensors.The strategy in harnessing the SACs onto the carbon inks thus provides a broad prospect for the low-cost and large-scale printing of sensitive sensing devices.
基金Project(51221462) supported by the National Natural Science Foundation of ChinaProject(20120095110001) supported by the Ph D Programs Foundation of Ministry of Education of China
文摘Demand for large vibrating screen is huge in the mineral processing industry. As bending and random vibration are not considered in a traditional design method for beam structures of a large vibrating screen, fatigue damage occurs frequently to affect the screening performance. This work aims to conduct a systematic mechanics analysis of the beam structures and improve the design method. Total motion of a beam structure in screening process can be decomposed into the traditional followed rigid translation(FRT), bending vibration(BV) and axial linear-distributed random rigid translation(ALRRT) excited by the side-plates. When treated as a generalized single-degree-of-freedom(SDOF) elastic system analytically, the BV can be solved by the Rayleigh's method. Stochastic analysis for random process is conducted for the detailed ALRRT calculation. Expressions for the mechanics property, namely, the shearing force and bending-moment with respect to BV and ALRRT, are derived, respectively. Experimental and numerical investigations demonstrate that the largest BV exists at the beam center and can be nearly ignored in comparison with the FRT during a simplified engineering design. With the BV and FRT considered, the mechanics property accords well with the practical situation with the maximum error of 6.33%, which is less than that obtained by traditional method.
