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91.
Public-lighting is a prominent subsector of the electricity distribution network. Removing upcoming challenges of the public-lighting system is an important necessity in network expansion planning. The public-lighting management structure is composed of three main participants: the regulatory unit, lighting managers, and private contractors. Each participant faces challenges in achieving its aims. This study investigates challenges in the areas of human resource management, cost estimation, price assignment, and time scheduling for private-sector contracting. Applying the reliability model of public-lighting lamps, the health status of lamps during the system operation is forecasted. In addition, to give a comprehensive solution for the mentioned challenges, the proposed strategies are optimized in terms of cost and risk. The results of this case study of the public-lighting system demonstrate the efficiency of the proposed method in alleviating the challenges of public-lighting managers, including optimal assignment of price and duration of contracts. In addition, the operating cost of the public-lighting system, an important challenge for lighting contractors, is minimized via a human resource management scheme. 相似文献
92.
《Advanced Powder Technology》2021,32(11):3964-3979
This work deals with the investigation and optimization of the crystalline phases, magnetic properties, chemical composition and morphology of Nd-(Fe1-xCox)-B oxide magnetic particles (where x = 0, 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, and 0.5) synthesized by Pechini method that can be used as a precursor for the production of Nd2(Fe,Co)14B hard magnetic phase. The polymerization mechanism of Pechini process was investigated by Fourier transform infrared (FTIR) and Raman spectroscopy to confirm the formation of metal-CA complexes and successive esterification reactions between citric acid (CA) and ethylene glycol (EG). The chemical composition of the synthesized samples was studied via energy dispersive (EDS) and X-ray photoelectro (XPS) spectroscopy methods. The structure, morphology, and the crystalline phase of resulting Nd-(Fe1-xCox)-B oxide magnetic particles were characterized by Rietveld refinement of X-ray diffraction (XRD) patterns, scanning electron microscopy ( SEM), and high-resolution transmission electron microscopy (HR-TEM) and its selected area electron diffractograms (SAED). The results obtained from the Rietveld refinement of XRD patterns show that (Fe2O3/Fe3O4) phase ratio decreases with the amount of cobalt that can be attributed to the reduction of enthalpy . The SEM micrographs indicate that the oxide particles have an elongated structure with irregular shapes supported by TEM observations. The results of structural analysis by HR-TEM and SAED are consistent with the Rietveld results which confirms the presence of different oxide phases in Nd-(Fe1-xCox)-B oxide particles. The magnetic behaviorstudied by VSM was interpreted by the variances of the morphology, structure and chemical composition of Nd-(Fe1-xCox)-B oxide particles, all of which were influenced by the cobalt content. First‐Order Reversal Curve (FORC) diagrams show that the magnetic interaction between oxide particles decreases as the cobalt content increases. 相似文献
93.
Lepeshev A. A. Pavlov A. V. Drokin N. A. Malkin A. I. Kiiko V. S. Knyazev N. S. 《Refractories and Industrial Ceramics》2019,60(3):309-317
Refractories and Industrial Ceramics - An electrically conducting two-component BeO-ceramic with the addition of micro- and nano-crystalline TiO2 powder is prepared that can be used as a material... 相似文献
94.
The possibilities of using back-pressure cogeneration turbines developed on the basis of serially produced ones are considered together with the thermal process circuits in which such turbines are applied. Design versions and advantages of cogeneration stations in which the proposed process circuits are implemented are described. 相似文献
95.
A. E. Valamin A. Yu. Kultyshev A. A. Gol’dberg Yu. A. Sakhnin V. N. Bilan M. Yu. Stepanov E. N. Polyaeva M. V. Shekhter T. L. Shibaev 《Thermal Engineering》2014,61(12):849-856
The article presents the design, the economic indicators, and the main solutions on the thermal process circuit and layout of the T-125/150-12.8 turbine, a new design version of the T-100-12.8 turbine, which is one of the best known, unique and widely used cogeneration turbines in Russia and abroad. The project of the new turbine is supposed to be used both for renovating and upgrading already installed turbines of the T-100 family and for supplying it as a full set for replacing obsolete equipment or constructing new one. 相似文献
96.
Scissor shears are affine transformations in 3-space that, in analogy with the usual rotations, can be understood as hyperbolic rotations about a fixed line, in a fixed coordinate frame. We study algebraic surfaces invariant under scissor shears, and investigate their similarities and differences with the algebraic surfaces invariant under the usual rotations, namely the algebraic surfaces of revolution. In particular, we provide a necessary condition for an algebraic surface to be invariant under scissor shears, and we prove that such shear invariant surfaces can have either one, three, or infinitely many scissor axes. Furthermore, we characterize the surfaces with either three or infinitely many scissor axes. Additionally, in each case we show how to calculate the location of these scissor axes as well as the rest of the coordinate frame. 相似文献
97.
《Journal of the European Ceramic Society》2022,42(13):5606-5614
Manipulating the critical switching field between antiferroelectric (AFE) state and ferroelectric (FE) is an important concept for tuning the energy storage performance of AFEs. As one of the lead-based AFE systems, Pb(Lu1/2Nb1/2)O3 promises high potential in the miniaturization of pulsed power capacitors, but the extremely high critical switching field and low induced saturated polarization demonstrate severe drawbacks with respect to temperature stability and flexibility. Here, A-site Ba2+ doping engineering is used to effectively reduce the critical switching field and improve the saturated polarization in BaxPb1-x(Lu1/2Nb1/2)O3 (0.01 ≤ x ≤ 0.08, abbreviated as xBa-PLN) ceramics. We found the AFE-FE phase transition can be occurred at 80ºC with a high energy storage density of 4.03 J/cm3 for Ba0.06Pb0.94(Lu1/2Nb1/2)O3 ceramic. Our results show that Ba2+ additions destroy the antiparallel structure of AFE phase, and finally reduce the critical switching field, demonstrating a potential alternative to modulate the energy storage performance of AFEs. 相似文献
98.
《Ceramics International》2022,48(5):6124-6130
The behaviour of the promising glass sealant 54.4SiO2-13.7Na2O-1.7K2O-5.0CaO-12.4MgO-0.6Y2O3-11.3Al2O3-0.9B2O3 for solid oxide fuel cells (SOFCs) under SOFC operating conditions was studied. First, the kinetics of the crystallisation processes at the operating temperature (850 °C) was discussed (maximum exposure time of 1000 h), and the effect of crystallisation on the coefficient of thermal expansion (CTE) of the sealant was studied. Furthermore, the degradation processes at the interface of the glass sealant and functional SOFC materials (Crofer 22 APU, YSZ, and NiO(Ni)-YSZ) during exposure to 850 °C in oxidising and reducing atmospheres for 500 h were studied. The tests demonstrated good performance of the sealant studied and possibility of its application in SOFCs. 相似文献
99.
《Ceramics International》2022,48(21):31811-31817
As one of the outstanding piezoelectric materials, relaxor-PbTiO3 single crystal also exhibits promising electro-optic and nonlinear-optic properties. Therefore, it is vital to understand the domain switching kinetics not only for optimizing strain-mediated devices performance but also for fabricating optical waveguides and periodic domain structures in optical applications. In this work, domain switching kinetics in annealed and pre-poled PMN-0.38PT single crystal under different external electric field were studied. Polarization reversal can be accomplished only by c-domain nucleation and growth in the annealed sample where the formation of the ferroelastic domains is hindered. In pre-poled sample, 90° domain switching happened by 90° domain wall reorientation under low electric field while 180° domain switching is accomplished by two-step 90° domain switching and c-domain growth under high electric field. The results are important for modulating domain structure for strain mediated and optical devices. 相似文献
100.
《Journal of the European Ceramic Society》2022,42(11):4528-4538
Ideal relaxor antiferroelectrics (RAFEs) have high field-induced polarization, low remnant polarization and very slim hysteresis, which can generate high recoverable energy storage Wrec and high energy storage efficiency η, thus attracting much attention for energy storage applications. True RAFEs, on the other hand, are extremely rare, and the majority of them contain environmentally hazardous lead. In this work, we use a viscous polymer rolling process to synthesize a novel and eco-friendly 0.65Bi0.5Na0.4K0.1TiO3-0.35[2/3SrTiO3-1/3Bi(Mg2/3Nb1/3)O3] (BNKT-ST-BMN) dielectric material, which possesses a very typical RAFE-like characteristic. As a result, this material has a high Wrec of 4.43 J/cm3 and a η of 86% at an electric felid of 290 kV/cm, as well as a high thermal stability of Wrec (>3 J/cm3) over a wide range of 30–140 °C at 250 kV/cm. Our findings suggest that the BNKT-ST-BMN material could be a potential candidate for use in energy storage pulse capacitors. 相似文献