Co-pyrolysis characteristics of typical components of waste plastics in a falling film pyrolysis reactor

Waste plastics mainly come from MSW and usually exist in the form of mixed plastics. During the co-pyrolysis process of mixed plastics, various plastic components have different physicochemical properties and reaction mechanisms. Considering the high viscosity and low thermal conductivity of molten plastics, a falling film pyrolysis reactor was selected to explore the rapid co-pyrolysis process of typical plastic components(PP, PE and PS).The oil and gas yields and the compositions of pyrolysis products of the three components under different ratios at pyrolysis temperatures were analyzed to explore the co-pyrolysis characteristics of PP, PE, and PS. The study is of great significance to the recycling of waste plastics.

Dielectric Properties of ZrTiO4 Thin Films Prepared by Reactive DC Magnetron Co-sputtering

ZrTiO4 is a small ceramic constituent material which has very good thermal and electrical properties. ZrTiO4 thin films were deposited by reactive dc magnetron co-sputtering method. The crystal structure, surface morphology, thickness and dielectric properties were characterized by XRD （X-ray diffraction）, AFM （atomic force microscopy）, FE-SEM （field emission scanning electron microscope）, and precision impedance analyzer respectively. These films were crystallization of the orthorhombic phase （111） of ZrTiOa. The microstructure of well-crystallized ZrTiO4 thin films had the surface morphology was smooth with 1.695 nmrms roughness. The high dielectric constant width decreases from 129.2 to 110.6 when sputtering current increases which are higher more than that had researched because of higher energy but impedance; ｜Z｜ increases from 1.97 to 2.47 kΩ. These results are consistent with the RMS roughness results, which are the RMS roughness decrease with increasing sputtering current.

Voltage-Based Hot-Spot Detection Method for Defective Cell in Photovoltaic Module Using Projector

This paper proposes a voltage-based hot-spot detection method for defective cells in PV module using projector. The presence of internal crystal defects is one of the main causes of hot-spot phenomenon in PV modules. Authors previously investigated the physical characteristics of hot-spot phenomenon referring to internal crystal defect. Based on it, a hot-spot detection method named as current-based SRC （self reverse current） detection method is developed. However, it becomes extraordinarily complicated to determine the defective cells under low illumination. In order to avoid this disadvantage, authors improve the SRC detection method by applying voltage. From the feasibility experiment results, it is confirmed that by calculating cell HSI （hotspots index） with voltage, the PV modules with defective cells can be prospectively excluded even under low illumination.

Molten waste plastic pyrolysis in a vertical falling film reactor and the influence of temperature on the pyrolysis products

Molten plastics are characterised with high viscosity and low thermal conductivity. Applying falling film pyrolysis reactor to deal with waste plastics can not only improve heat transfer efficiency, but also solve the flow problem. In this work, the pyrolysis process of molten polypropylene （PP） in a vertical falling film reactor is experimentally studied, and the influence of heating temperature on pyrolysis products is discussed. It has been found that with the temperature increases from 550 ℃ to 625 ℃, the yield of pyrolysis oil decreases from 74.4 wt% （ 4- 2.2 wt/%） to 53.5 wt% （± 1.3 wt%）. The major compositions of the pyrolysis oil are C9, C12 and C18, and β-scission reactions are predominant. The content of the light fraction C6-C12 of pyrolysis oil is 69.7 wt%. Compared with other pyrolysis reactors, the yield ofoil from vertical falling film pyrolysis reactor is slightly higher than that from tubular reactor, equal to that from rotary kiln reactor, and slightly lower than that in medium fluidised-bed reactor.

一个电影理论学派的诞生:英美早期女性主义电影理论与批评述评

女性主义电影理论在20世纪60年代中期到70年代初期承继了女性主义和电影研究对许多相关议题的讨论,有力揭示了古典好莱坞在电影文化生产中对女性的压迫与剥削,并在此基础上提出了“女性集体创作”“反-电影”等富有建构意义的创作观念、理论与批评构想。尽管早期女性主义电影理论存在政治激进和本质主义倾向等不足和误区,但这些投身创作和批评实践的理论家们却为女性主义理论与批评在20世纪70年代中期以后的发展演变奠定了重要基础,她们的实践彰显了把批评实践和理论建构、个体经验与其所属性别群体的生存境况、重写女性影史和现实政治诉求紧密结合起来的理论建构的主体意识和智慧。

Enhanced piezo-response in copper halide perovskites based PVDF composite films

ln-situ fabricated perovskite nanocrystals in polymeric matrix provide new generation composite mate- rials for plenty of cutting edge technology. In this work, we report the in-situ fabrication of copper halide perovskite （MA_2CuCI_4, MA：CH_3NH＋3） embedded poly（vinylidene fluoride） （PVDF） composite films. The optimized MA_2CuCI_4/PVDF composite films exhibit greatly enhanced piezo-response in comparasion with pure PVDF films. The enhancements were invesitgated and explained by applying piezo-response force microscopy （PFM） measurements and density functional theory （DFT） caculations. We proposed that the high piezoelectric properties of MA_2CuCI_4/PVDF composite films could be related to the large Cu off-centering displacement, the strong interactions between MA_2CuCI_4 and PVDF as well as large stress concentration around the MA_2CuCI_4 particles in the films. These piezoelectric composite films are expected to be suitable functional materials for flexible and/or wearable niezoelectrics.

Modeling of Thermal Properties of Thermal Insulation Layered with Transparent,Opaque and Reflective Film

The popular and effective food preservation technology based on refrigeration is not sufficient for high-quality products while undergoing logistic operations(transport and retail). One of the basic factors that affects the quality of chilled and frozen food products during storage and transport is packaging. A protective function of packaging strongly depends on the material used and its composition. There are different kinds of thermal insulation used for food packaging. One of them, proposed by the authors is a multilayer structure of insulation made of rectangular air cells. The insulation can be prepared by means of plastic film featuring various properties. The paper presents how to improve an effective material designed for food freezing and transport aiming to enhance its thermal resistance through the application of different transparency, reflectivity and emissivity of the film. Mathematical model based on heat exchange equations, including conduction, convection and radiation throughout a number of parallel internal sheets of film of multilayer structures was proposed. Thermal properties depending on different transparency, reflectivity and emissivity of the film were analyzed. The model was verified experimentally showing its compatibility and obtaining a significant influence of thermal resistance according to the type of film used to make air structures, the number and thickness of its layers as well as the gaps between internal folds. For multi-layer insulation designed for the insulation of packed frozen food in the shape of a rectangle, it was recommended to apply film transmittance as small as possible for the internal parts of the structure.