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1.
A novel bio‐based composite material, suitable for electronic as well as automotive and aeronautical applications, was developed from soybean oils and keratin feather fibers (KF). This environmentally friendly, low‐cost composite can be a substitute for petroleum‐based composite materials. Keratin fibers are a hollow, light, and tough material and are compatible with several soybean (S) resins, such as acrylated epoxidized soybean oil (AESO). The new KFS lightweight composites have a density ρ ≈ 1 g/cm3, when the KF volume fraction is 30%. The hollow keratin fibers were not filled by resin infusion and the composite retained a significant volume of air in the hollow structure of the fibers. Due to the retained air, the dielectric constant, k, of the composite material was in the range of 1.7–2.7, depending on the fiber volume fraction, and these values are significantly lower than the conventional silicon dioxide or epoxy, or polymer dielectric insulators. The coefficient of thermal expansion (CTE) of the 30 wt % composite was 67.4 ppm/°C; this value is low enough for electronic application and similar to the value of silicon materials or polyimides used in printed circuit boards. The water absorption of the AESO polymer was 0.5 wt % at equilibrium and the diffusion coefficient in the KFS composites was dependent on the keratin fiber content. The incorporation of keratin fibers in the soy oil polymer enhanced the mechanical properties such as storage modulus, fracture toughness, and flexural properties, ca. 100% increase at 30 vol %. The fracture energy of a single keratin fiber in the composite was determined to be about 3 kJ/m2 with a fracture stress of about 100–200 MPa. Considerable improvements in the KFS composite properties should be possible by optimization of the resin structure and fiber selection. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1524–1538, 2005 相似文献
2.
海洋废弃平台拆除过程中需要切断桩基,水下绳锯机是一种安全环保的桩基切割工具.介绍了绳锯机的工作原理,提出了控制系统的总体结构,设计了控制系统的硬件和软件,实验表明此控制系统能够使绳锯机安全、稳定的工作. 相似文献
3.
龙婷 《湖南工业职业技术学院学报》2014,(4):27-30
近年来,逆向物流逐渐成为物流领域研究的新热点受到国内外学者的高度重视。文章从分析我国逆向物流的现状入手,从废弃家电产品回收、消费资源重新利用及从企业长远发展要求的角度探讨了我国生产企业实施逆向物流的必要性,并为我国各类生产企业实施逆向物流提供了切实可行的实施方案。 相似文献
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刘魁元 《油气地质与采收率》2007,14(4):106-110
通过对河口探区内370口已经核销的老探井进行重新评价,认为受地质认识和采油工艺局限性的影响有21口已经核销的老探井初次试油不彻底。随着地质认识的不断完善和采油工艺的不断改进,对其中的17口井进行了重新试油均获得成功,产油量由8.94t/d增加到73.9t/d,新增探明石油地质储量6063×104t。实施核销探井再评价,不仅深化了地质认识,盘活了闲置资产,缩短了增储周期,降低了勘探成本,而且通过出油井点的突破,找到了一条高勘探成熟地区油气勘探的路子。 相似文献
8.
唐山市古冶区工业废弃地活化与再生策略研究 总被引:2,自引:1,他引:1
在综合分析现状的基础上,提出了唐山市古冶区工业废弃地活化与再生的原理、目标及实施策略。 相似文献
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电牵引采煤机调高系统事故频繁发生,原因是煤机液压系统在恶劣生产条件下容易受到污染,电磁阀组堵塞,憋卡现象严重。对调高系统进行改造,把原电磁阀组甩掉,调高系统由电动控制改为手动控制,提高了开机率,大大降低了工人的劳动强度。 相似文献
10.
Javiera Cornejo Ekaterina Pokrant Carolina Carvallo Aldo Maddaleno Betty San Martín 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2018,35(3):448-457
Tylosin is one of the most commonly used antimicrobial drugs from the macrolide family and in broiler chickens it is used specially for the treatment of infectious pathologies. The poultry industry produces several by-products, among which feathers account for up to 7% of a chicken’s live weight, thus they amount to a substantial mass across the whole industry. Feathers have been repurposed as an animal feed ingredient by making them feather meal. Therefore, the presence of high concentrations of residues from antimicrobial drugs in feathers might pose a risk to global public health, due to re-entry of these residues into the food chain. This work aimed to characterise the depletion behaviour of tylosin in feather samples, while considering its depletion in muscle and liver tissue samples as a reference point. To achieve this goal, we have implemented and validated an analytical methodology suitable for detecting and quantifying tylosin in these matrices. Sixty broiler chickens, raised under controlled conditions, received an oral dose of 32 mg kg-1 of tylosin for 5 days. Tylosin was quantified in muscle, liver and feathers by liquid chromatography coupled with a photodiode array detector (HPLC-DAD). High concentrations of tylosin were detected in feather samples over the whole experimental period after completing both the therapy and the recommended withdrawal time (WDT). On the other hand, tylosin concentrations in muscle and liver tissue samples fell below the limit of detection of this method on the first sampling day. Our results indicate that the WDT for feather samples is 27 days, hence using feather meal for the formulation of animal diets or for other agricultural purposes could contaminate with antimicrobial residues either other livestock species or the environment. In consequence, we recommend monitoring this matrix when birds have been treated with tylosin, within the context of poultry farming. 相似文献