Ductility of polylactide composites reinforced with poly(butylene succinate) nanofibers

Sustainable “green nanocomposites” of polylactide (PLA) and poly(1,4-butylene succinate) (PBS) were obtained by slit die extrusion at low temperature. Dispersed PBS inclusions were sheared and longitudinally deformed with simultaneous cooling in a slot capillary and PBS nanofibers were formed. Shearing of PBS increases nonisothermal crystallization temperature by 30 °C. Tensile deformation was investigated by in-situ experiments in SEM chamber. Dominant deformation mechanism of PLA is crazing, however, there are dormant shear bands formed during slit die extrusion. Pre-existing shear bands are inactive in tensile deformation but contribute to ductility by blocking, initiating and diffusing typical craze growth. PBS nanofibers are spanning PLA craze surfaces and bridging craze gaps when PLA nanofibrils broke at large strain. Straight crazes become undulated because either dormant or new shear bands become activated between crazes. Due to interaction of crazes and shear bands the ductility increases while high strength and stiffness are retained.     

我国核电涂料发展概况

从我国核电涂料研究发展现状出发,分析总结了核电涂料的分类、技术标准、主要类型、产品应用,指出我国核电涂料的发展前景。     

风电叶片涂料用树脂研究进展

风电叶片作为风机设备的核心部位,保证其良好运行,既可以提高发电效率,又能降低维护成本.受自然环境的影响,长时间运行的风电叶片往往比较脆弱,尤其是叶片前缘部位,极易受到风沙及雨蚀的损坏,目前最简单有效的方法是使用涂料进行防护.根据风电叶片所处的工作环境特点,提出了对防护涂料的主要要求.介绍了适用于风电叶片防护涂料的基体树脂,包括聚氨酯树脂、丙烯酸树脂、氟树脂、有机硅树脂和环氧树脂,并分别详细阐述了它们在风电叶片防护涂料方面的国内外研究进展及目前的应用.聚氨酯和丙烯酸聚氨酯树脂是目前使用最多的树脂,在高低温柔韧性、耐磨性及防风沙雨蚀方面表现优异,而氟树脂和有机硅树脂因优异的耐候性和防覆冰性也受到了越来越多的关注,环氧树脂则可以为叶片底漆提供优异的防腐性能和层间附着力.与使用单一树脂相比,针对不同树脂各自的特点,对它们进行合理搭配,制得的配套涂层体系往往可以达到更好的防护效果,这仍然会是今后的主要研究思路.最后指出了目前风电叶片涂料市场的国内外差距,并展望了风电叶片防护涂料未来的发展方向.     

Superhigh selective capture of volatile organic compounds exploiting cigarette butts-derived engineering carbonaceous adsorbent

Herein, we develop cost-efficient superhigh-performance of engineering carbonaceous adsorbent from cigarette butts using combined wet-impregnated and re-dispersed method of KOH, which optimizes the implant approach of activator, breaking the restriction of selective capture of toluene using traditional activated carbon. The Brunauer-Emmett-Teller (BET) surface area and pore volume of targeted adsorbent can attain 3088 m²·g^-1 and 1.61 cm³·g^-1, respectively, by optimizing the temperature-dependent synthetic factor effect of the adsorbent. The adsorption capacity of resultant adsorbent for presenting volatile benzene and toluene shows a positive correlation with increasing carbonization temperature of carbon precursor. Besides, we demonstrated the unsmoked and smoked butts derived adsorbents afford feeble difference in saturated adsorbed capacity of volatile organic compounds (VOCs). The highest adsorption capacity of sample CF-800 for benzene and toluene in CF group is as high as 1268.1 and 1181.6 mg·g^-1 respectively, slightly higher than that of sample UF-800, but far outperforming reported other adsorbents. The predicted adsorption selectivity of CF-800 and UF-800 for C₇H₈/H₂O (g) using the DIH (difference of isosteric heats) equation reach up to ca. 3800 and 7500 respectively, indicating the weak adsorbability of water vapor on the developed adsorbent and greater superiority of the smoked butts derived adsorbents in selective capture of VOCs at low relative humidity in the competitive adsorption process for practical mixed VOCs.     

Low-temperature water–gas shift reaction over supported Cu catalysts

The low-temperature water–gas shift (WGS) reaction has been carried out at a very high gas hourly space velocity (GHSV) of 36,201 h⁻¹ over supported Cu catalysts prepared by an incipient wetness impregnation method. The preparation method was optimized to get a highly active CeO₂ supported Cu catalyst for low-temperature WGS. Co-precipitated Cu–CeO₂ exhibited excellent catalytic performance as well as 100% CO₂ selectivity. The high activity and stability of co-precipitated Cu–CeO₂ catalyst is correlated to its easier reducibility, high surface area and the nano-sized CeO₂ with CuO species interacting with the support.     

Galvanic corrosion of carbon steel coupled to antimony

Galvanic corrosion of carbon steel coupled to antimony was studied in aerated and N₂-purged electrolytes at ambient and 60 °C temperatures. Free corrosion potential of antimony and carbon steel shifts to more active values with increasing temperature and N₂ purging of the electrolyte. Under all experimental conditions, antimony remains less electronegative than carbon steels. Aeration and temperature affect potentiodynamic behaviour of both materials. As a consequence, the corrosion current for the antimony–carbon steel couple increases with increasing temperature and with aeration. There was a good agreement between the corrosion currents obtained through the Evans’ experiment and super-imposed potentiodynamic scans.     

Sensitivity of tag-recovery mortality estimates to inaccuracies in tag shedding,handling mortality,and tag reporting

We used Monte Carlo simulations to evaluate the sensitivity of tag-recovery mortality estimates to inaccuracies in tag shedding, handling mortality, and tag reporting. The data-generating model used in the simulations assumed that tagging was conducted annually for 4 years with tag recoveries occurring over a 4-year period. Several different combinations of instantaneous fishing (F) and natural (M) mortality were evaluated in the simulations. The data-generating model additionally assumed that immediate-shedding and handling-mortality rates equaled 2.5% and 0%, respectively, and that chronic shedding was a sigmoidal function of months since tagging. Two spatial patterns of reporting rates were considered—one where reporting was a function of distance from the tagging site and one where reporting was a random generation across the study area. Maximum likelihood estimates of F and M were calculated from the recovery of tags from the data-generating model under different assumed rates of tag shedding, handling mortality, and tag reporting. We found that assumptions about reporting rates resulted in the most variability in mortality estimates regardless of which combination of F and M was evaluated, with assumptions about chronic shedding also contributing substantially to overall variability in mortality estimates for most mortality combinations. Assumptions about immediate tag shedding and handling mortality had relatively minor effects on mortality estimates compared to reporting rate. When planning a tag-recovery study, care should be taken to ensure that chronic shedding and tag-reporting rates are accurately measured, as inaccurate measurements in these factors can result in significant errors in mortality estimates.     

A kinetic study of gaseous alkali capture by kaolin in the fixed bed reactor equipped with an alkali detector

In this study, the interaction between gas phase potassium species and kaolin was investigated in a fixed bed reactor equipped with a surface ionization detector, which is capable of detecting alkali metals in gas phase at ppb level. The effects of mass transport, space time, sorbent temperature and concentration of KCl on the rate of potassium adsorption on kaolin were studied in air. Kaolin, mainly composed of kaolinite—Al₂Si₂O₅(OH)₄, was found to be very efficient in removing gaseous alkali species from hot flue gases at fluidized bed combustion temperatures. The removal efficiency increased as temperature was decreased or KCl concentration was increased. The capture of potassium by kaolin was irreversible with formation of both water-soluble and water-insoluble products. Kaolin captured KOH almost as effectively as KCl, but K₂SO₄ was captured much less effectively than KCl.     

Evaluation of biosynthesized nickel oxide nanoparticles from Clerodendrum phlomidis: A promising photocatalyst for methylene blue and acid blue dyes degradation

In the present investigation, nickel oxide nanoparticles (NiO) were biosynthesized utilizing an extract of Clerodendrum phlomidis leaves. Their size, phase study, and shape were investigated using a variety of research methods. In addition, we assessed the photocatalytic effects of NiO nanoparticles on the degradation of methylene blue (MB) and acid blue (AB) dyes. Throughout the research process, we found that these nanoparticles had extraordinary potential for photocatalysis when exposed to UV light. This is a 100% environmentally friendly method that makes no use of any harmful or poisonous solvents. High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and ultraviolet–visible spectroscopy (UV–Vis) were used to analyze the biosynthesized NiO nanoparticles. The catalytic activity of the newly synthesized nanoparticles was evaluated by seeing how well they degraded dyes called methylene (MB) and acid blue (AB). Following the first-order reaction, kinetics was the photocatalytic effectiveness against the methylene blue (MB) and acid blue (AB) dyes, both of which exhibited a maximum degradation efficiency of 92% and 63%. Because of this, the biosynthesized NiO nanoparticles synthesized utilizing the extract of Clerodendrum phlomidis leaves have the potential to be used in photocatalytic applications.