In situ polymerization of flame retardant modification polyamide 6,6 with 2-carboxy ethyl (phenyl) phosphinic acid

A novel halogen-free flame retardant copolyamide 6,6 (FR-PA66) was prepared successfully by in situ polymerizing with adipic acid hexamethylene salt and 2-carboxy ethyl (phenyl) phosphinic acid (CEPPA). The elemental composition and chemical structure of FR-PA66 were characterized by energy dispersive X-ray spectroscopy, Fourier transform infrared spectrometer and ¹³C Nuclear magnetic resonance spectrometer. The flame retardancy, thermal stability, and morphology of char residues were also investigated by the limiting oxygen index (LOI), UL 94 test, thermogravimetric analysis, and scanning electron microscopy. The results showed that FR-PA66 samples had much better flame retardancy and char formation ability than pure PA66 after the flame retardant modification. The LOI values were increased from 24.0 to 28.0% by adding 6 wt % of CEPPA and all FR-PA66 samples were rated as V-0 rating in UL-94 test. Furthermore, the thermal stability analysis indicated that in situ polymerization with CEPPA effectively decreased the initial decomposition temperature and increased the amount of char residue. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48687.     

Heavy rare earths,permanent magnets,and renewable energies: An imminent crisis

This article sounds the alarm that a significant build-out of efficient lighting and renewable energy technologies may be endangered by shortages of rare earths and rare earth permanent magnets. At the moment, China is the predominant supplier of both and its recent rare earth industrial policies combined with its own growing demand for rare earths have caused widespread concern. To diversify supplies, new mining—outside of China—is needed. But what many observers of the “rare earth problem” overlook is that China also dominates in (1) the processing of rare earths, particularly the less abundant heavy rare earths, and (2) the supply chains for permanent magnets. Heavy rare earths and permanent magnets are critical for many renewable energy technologies, and it will require decades to develop new non-Chinese deposits, processing capacity, and supply chains. This article clarifies several misconceptions, evaluates frequently proposed solutions, and urges policy makers outside of China to undertake measures to avert a crisis, such as greater support for research and development and for the cultivation of intellectual capital.     

Solvent-free synthesis of C9 and C10 branched alkanes with furfural and 3-pentanone from lignocellulose

Jet fuel range branched alkanes were first synthesized under solvent-free conditions by the aldol condensation of furfural and 3-pentanone from lignocellulose followed by the one-step hydrodeoxygenation (HDO). Among the investigated solid base catalysts, CaO and KF/Al₂O₃ demonstrated the highest activity for the aldol condensation reaction of furfural and 3-pentanone. The aldol condensation product of furfural and 3-pentanone (liquid at room temperature) was directly hydrodeoxygenated to 4-methyl-nonane and 4-methyl-octane. These alkanes have low freezing points (174.1 K and 159.8 K) and can be blended into jet fuel without hydroisomerization. Among the investigated HDO catalysts, the Ni-Cu/SiO₂ exhibited the best performance.     

Unveiling the role of Fe3O4in polymer spin valve near Verwey transition

The spinterface formed between ferromagnetic(FM)electrode and organic materials is vital for performance optimization in organic spin valve(OSV).Half-metallic Fe₃O₄with drastic change in structure,conductivity and magnetic property near Verwey transition can serve as an intrinsic spinterface regulator.However,such modulating effect of Fe₃O₄in OSV has not been comprehensively investigated,especially below the Verwey transition temperature(Tv).Here,we highlight the important role of Fe₃O₄electrode in reliable-working and controllable Fe₃O₄/P3HT/Co polymer spin valves by investigating the magnetoresistance(MR)above and below 7V.In order to distinguish between different contributions to charge transport and related MR responses,the systematic electronic and magnetic characterizations were carried out in full temperature range.Particularly,the first-order metal-insulator transition in Fe₃O₄has a dramatic effect on the MR enhancement of polymer spin valves at 7V.Moreover,both the conducting mode transformation and MR line shape modulation could be accomplished across 7V.This research renders unique scenario to multimodal storage by external thermodynamic parameters,and further reveals the importance of spin-dependent interfacial modification in polymer spin valves.     

基于改进NSGA-Ⅱ算法的乙烯裂解炉操作优化

现有的乙烯裂解炉优化通常只针对两个目标函数即产物乙烯和丙烯的收率，并且采用遗传算法的收敛效果一般，故提出一种基于改进NSGA-Ⅱ算法来研究一个多目标运行的解决方案，以此来解决乙烯裂解炉的固定周期操作优化问题，即在增大产物乙烯和丙烯收率的同时减少原料以及蒸汽流量来提高整体运行状况。把具体问题量化为数学模型，分析了原料气烃比、原料流量、出口温度对乙烯和丙烯收率的影响。实验结果表明，相较于原有操作条件，提出的优化方案具有良好的可行性。     

Hygrothermal deformation of orthotropic nanoplates based on the state-space concept

This paper deals with the investigation of the effect of hygrothermal conditions on the bending of nanoplates using Levy type solution model employing the state-space concept. The nanoplates are assumed to be subjected to a hygrothermal environment. The two-unknown function plate theory is used to derive the governing differential equations on the basis of Eringen's nonlocal elasticity theory. The governing equations contain the small scale effect as well as hygrothermal and mechanical effects. These equations are converted into a set of first-order linear ordinary differential equations with constant coefficients. Analytical solution of bending response for nanoplates under combinations of simply supported, clamped and free boundary conditions is obtained. Comparison of the results with those being in the open literature is made. The influences played by small scale parameter, temperature rise, the degree of moisture concentration, boundary conditions, plate aspect ratio and side-to-thickness ratio are studied.     

A novel utilized method of tar derived from biomass gasification for fabricating binder-free all-solid-state hybrid supercapacitors

As an industrial pollutant, tar derived from biomass gasification is used as the precursor for fabricating a novel carbon-metal hydroxides composite electrode. A slurry (the mixture of tar, KOH and melamine) is daubed uniformly onto the nickel foam, which is directly carbonized to form NPC@LDH electrode material. This electrode is further coated with NiCo-LDH nanosheets using an electrodeposition method to form NF@NPC@LDH. The newly made NF@NPC@LDH electrode exhibits a high specific capacity of 9.6 F cm⁻² at a current density of 2 mA cm⁻² and good rate performance (55.3% retention). Furthermore, a hybrid NF@NPC@LDH//NF@PC all-solid-state supercapacitor is fabricated, and the device exhibits high energy density of 1.28 mWh cm⁻³ at a power density of 8.04 mW cm⁻³, low resistance and good cycling stability.     

Cold chain maintaining in food trade

The concept of food safety has lately acquired a new approach due to globalization and free trade in food. Introducing a HACCP system in the production and trade in food has become a necessity. The term “food trade” indicates all the postproduction procedures, from storage, transport and distribution to retail, including export and import. The aim of our 2002 survey was to analyse the situation of cold chain maintaining in food trade in Ljubljana, the capital of Slovenia. The research was based upon two hypotheses: in the first one we supposed that a cold chain is interrupted in retail and in the second one we supposed that the handling of food in retail varies. Seventeen stores were divided in three groups, according to sales area of the store: large ones, medium ones and small ones. Temperature conditions in cooling appliances for storage of 1688 perishable food products were measured. Products were inspected by two criteria, by the “best before” date and by the storage temperature. The results confirmed both of the hypotheses. The storage conditions were properly labelled on the packages of the products inspected. In most of the cases the temperatures measured differed from the required ones, even for up to 10 °C. The biggest differences were detected between temperatures indicated on cooling appliances and temperatures measured by our calibrated thermometers. Conditions during food storage and in retail stores were not documented and there was no system to control the cold chain. Our findings have shown that retailers are not familiar with the importance of maintaining a cold chain. The result of that can be a shorter durability of highly perishable foodstuffs and their safety for consumers is questionable.     

多孔陶瓷载体氧化铝涂层的研究

分别用纳米γ-Al₂O₃和SB粉制备了多孔陶瓷载体的Al₂O₃涂层。BET法测定了多孔陶瓷载体Al₂O₃涂层改性前后比表面积的变化。由SEM照片观察多孔陶瓷载体涂层改性前后表面和断面的形貌。结果表明，这两种方法对多孔陶瓷载体涂层改性均有效可行。