Preloading using fill surcharge and prefabricated vertical drains for an airport

This paper presents the field measurements and analysis of a preloading project with the installation of prefabricated vertical drains (PVDs) in Wenzhou, China. At the site, PVDs were installed to a depth of 22?m from the ground surface with a spacing of 1.5?m in a triangular pattern. The preloading fill thickness was 6?m with a unit weight of approximately 18 kN/m³. After a total elapsed time of 310 days, approximately 3?m thick fill was removed. The measured preloading settlement was approximately 1.5?m. The measurements and analytical results indicated that the soil layer with PVD improvement reached almost 100% primary consolidation when part of the fill was removed. After partial unloading, the PVD-improved zone was in an over-consolidated state. After the runway was opened for traffic, a settlement increment of approximately 7?mm was monitored over a period of 11 months. Analysis indicated that the settlement was mainly due to the consolidation of soil layers below the PVD-improved zone and post-surcharge secondary consolidation of the PVD-improved zone. The values of the parameters related to PVD improvement were back-estimated from the field measurements. These findings can be used to guide the design of PVDs improvement along the east coast of China.     

Optimal operation of cogeneration system coordinated by aggregator for providing the demand and supply regulation capacity

Recent growth of renewable energy generations with natural variability, such as photovoltaic generation and wind turbine generation, would make the demand and supply control in a whole power system more difficult, and therefore, alternatives for demand and supply regulation resources would be required. The authors focus on cogeneration system (CGS) as one of regulation resources. In order to procure adequate volume of regulation capability, an aggregator coordinates a number of CGSs efficiently and flexibly considering the wide variety of electricity/thermal demands of CGS owners. This paper proposes a novel optimal operation strategy of CGS coordinated by the aggregator considering the energy balance and operation cost of individual CGS owner. This paper also demonstrates the availability of CGSs for regulation capability by numerical case studies in which the actual consumption profile is employed.     

基于时序数据的云网协同平台人工智能运维体系

云计算在企业应用中的拓展不但表现为平台规模的拓展，也表现为平台应用的延伸。“云网协同”和“微服务化”是当前企业云平台演进的重要趋势。随着企业信息化建设重要性的持续提升，微服务化云网协同平台的运行维护面临极大挑战。首先分析了平台运维面临的挑战，梳理了平台人工智能运维需求，提出了基于时序数据分析的平台人工智能运维技术体系，并给出了云网协同平台人工智能运维子系统参考设计。所提技术体系和系统设计具有实用性和推广性，可以作为企业云平台建设和优化的技术途径参考。     

High-Speed Trains Automatic Operation with Protection Constraints: A Resilient Nonlinear Gain-based Feedback Control Approach

This paper addresses the control design for automatic train operation of high-speed trains with protection constraints. A new resilient nonlinear gain-based feedback control approach is proposed, which is capable of guaranteeing, under some proper non-restrictive initial conditions, the protection constraints control raised by the distance-to-go (moving authority) curve and automatic train protection in practice. A new hyperbolic tangent function-based model is presented to mimic the whole operation process of high-speed trains. The proposed feedback control methods are easily implementable and computationally inexpensive because the presence of only two feedback gains guarantee satisfactory tracking performance and closed-loop stability, no adaptations of unknown parameters, function approximation of unknown nonlinearities, and attenuation of external disturbances in the proposed control strategies. Finally, rigorous proofs and comparative simulation results are given to demonstrate the effectiveness of the proposed approaches.      

A novel Temperature–Humidity–Time defrosting control method based on a frosting map for air-source heat pumps

To improve the defrosting accuracy and the energy efficiency of the air-source heat pump (ASHP) under frosting and defrosting conditions, a novel Temperature–Humidity–Time (T–H–T) defrosting control method, based on a frosting map for the ASHP unit, is proposed in this paper. A field test was conducted for two heating seasons, to verify the feasibility and applicability of the T–H–T method. The advantages of the T–H–T method, compared to the conventional Temperature–Time (T–T) defrosting control method, are presented. In total, eight cases are shown in this paper. Cases 1 to 4 were chosen to reveal the T–H–T performance under different frosting conditions. It was found that no matter what kind of frosting conditions, defrosting was always initiated in a similar situation: ∼90% of the outdoor coil surface was covered by frost; the temperature difference between the compressor suction and discharge increased by ∼20%; and the heating capacity decreased by ∼30%. These results indicate that the T–H–T method can make an accurate decision under different frosting conditions. Cases 5a, 5b and Cases 6a, 6b were two groups of cases to compare the advantages of the T–H–T method against the conventional T–T method. Cases 5a and 5b were chosen for the non-frosting condition. It was found that the T–T method initiated the defrosting operation 31 times within 24 h. However, none of the defrosting operations was conducted for the T–H–T method. Cases 6a and 6b were chosen to compare these two methods under consecutive and variable frosting conditions. For the T–T method, 63% of the defrosting processes were found to be executed under conditions where defrosting was not necessary. However, for the T–H–T method, all the defrosting controls were found to be accurate and reasonable. These results indicated that the novel T–H–T method is suitable for the defrosting control of the ASHP, and has a more competitive performance than the conventional T–T method.     

SMC-420型针梳机梳理牵伸的控制研究

文中阐述了SMC-420型针梳机梳理区的组成和工作结构,总结出梳理牵伸的操作控制方法,提高了毛条条干的控制水平。通过系统调整和不断优化,可改善腈纶毛条条干质量,降低腈纶毛条的毛粒、毛片的产生机率。     

Investigation of pitting corrosion monitoring using field signature method

The field signature method (FSM) is a nondestructive testing (NDT) method based on the potential drop (PD) technique and has been applied to online metal pipe corrosion monitoring for nearly three decades. The many advantages and benefits of the method have been reported in a number of studies, but few have reported on its limitations or shortcomings. However, the detection accuracy for pitting corrosion in FSM is very low. In this paper, the reasons for the low pitting corrosion detection accuracy of FSM were analyzed and it was found that different corrosion pits, which have different sizes, depths or positions, generally have differing influences on the potentials of nearby electrode pairs. Therefore, a new method using a subdivided resistor network to assess pitting corrosion is proposed and verified. When compared with the traditional method, the most important parameter, namely the pitting corrosion depth detection accuracy, can be significantly improved.     

Coastal trapped waves in the southern Caspian Sea

Previous studies reported coastal trapped waves (CTWs) in the Caspian Sea (CS). This study deals with the generation mechanisms, the temporal and spatial variability of CTWs in this area, and their transformations during propagation from the origin to the destination using recent measurements and high-resolution numerical simulations. CTWs are observed at all stations with periods of 2–6 days after northerly storms. The Absheron Peninsula, old Sefidrud delta, and Nur coasts were identified as the CTWs prone regions. The generation of CTWs in these locations was confirmed using numerical experiments. The propagation away from the generating location of CTWs was analyzed using a representative real wind storm. In the west part of the CS, the generation mechanism of CTWs is mainly similar to the barotropic Kelvin waves; in contrast, it is similar to the continental shelf waves in the southern shelves. The results can be used to study the contribution of generated CTWs to the transport of sediment and biological materials in all large lakes.     

Waveguide-based near-eye display with dual-channel exit pupil expander

We propose a waveguide-based near-eye display featuring a dual-channel exit pupil expander, which is composed of an in-coupler, relay gratings, and an out-coupler. Unlike the conventional waveguide-based near-eye displays, whose field of views are usually non-split or partially split, our dual-channel exit pupil expander is able to evenly split the field of view into two halves. The greatest benefit of doing so is that the upper limit of field of view could be significantly increased. The design rules for all components, including the microdisplay, collimating lens, waveguide and gratings, have been studied. The refractive index and dimension of waveguide are identified as two factors that limit the field of view. In what follows, its key specifications are recapitulated. Field of view is 70° (diagonal), eye relief is 15 mm, exit pupil is 20 × 9 mm², modulation transfer function is above 0.591 at 30 cycle/degree, contrast ratio is 13, and distortion is 1.38%.