Sustainable, thermoplastic and hydrophobic coating from natural cellulose and cinnamon to fabricate eco-friendly catering packaging

Non-degradable polymers cause serious environmental pollution problem,such as the widely-used while unrecyclable coatings which significantly affect the overall degradation performance of products.It is imperative and attractive to develop biodegradable functional coatings.Herein,we proposed a novel strategy to successfully prepare biodegradable,thermoplastic and hydrophobic coatings with high transparence and biosafety by weakening the interchain interactions between cellulose chain.The natural cellulose and cinnamic acid were as raw materials.Via reducing the degree of polymerization(DP)of cellulose and regulating the degree of substitution(DS)of cinnamate moiety,the obtained cellulose cinnamate(CC)exhibited not only the thermalflow behavior but also good biodegradability,which solves the conflict between the thermoplasticity and biodegradability in cellulose-based materials.The glass transition temperature(T_(g))and thermalflow temperature(T_(f))of the CC could be adjusted in a range of 150–200℃ and 180–210℃,respectively.The CC with DS<1.2 and DP≤100 degraded more than 60%after an enzyme treatment for 7 days,and degraded more than 80%after a composting treatment for 42 days.Furthermore,CC had no toxicity to human epidermal cells even at a high concentration(0.5 mg mL^(-1)).In addition,CC could be easily fabricated into multifunctional coating with high hydrophobicity,thermal adhesion and high transparence.Therefore,after combining with cellophane and paperboard,CC coating with low DP and DS could be used to prepare fully-biodegradable heat-sealing packaging,art paper,paper cups,paper straws and food packaging boxes.

Eco-friendly synthesis and environmental impact assessment of hierarchical Beta zeolite from kaolinite and recycled mother liquor

The development of sustainable techniques to produce high-performance zeolite is essential to achieve green production in industry.Herein,we report an eco-friendly route to synthesizing hierarchical Beta zeolite from kaolinite and recycled mother liquor.The results reveal that the unutilized species(such as silicon species and Na+)in mother liquor stayed in a stable concentration during eleven recycled experiments.Moreover,the synthesized Beta zeolites still have comparable physicochemical properties and catalytic performance in the esterification of levulinic acid with ethanol over the initial zeolite although eleven recycled experiments.Life cycle assessment exhibits that the synthesis of Beta zeolite with recycled mother liquor can reduce global warming potential by 23%and resource depletion-water use by 36%compared to that without recycled mother liquor.This quantitatively demonstrates that the approach proposed in this work is really a sustainable one,extremely increasing the utilization efficiency of raw materials and decreasing the environmental burden.

Exploring an eco-friendly approach to improve soil tensile behavior and cracking resistance

Soil tensile strength is a critical parameter governing the initiation and propagation of tensile cracking.This study proposes an eco-friendly approach to improve the tensile behavior and crack resistance of clayey soils.To validate the feasibility and efficacy of the proposed approach,direct tensile tests were employed to determine the tensile strength of the compacted soil with different W-OH treatment concentrations and water contents.Desiccation tests were also performed to evaluate the effectiveness of W-OH treatment in enhancing soil tensile cracking resistance.During this period,the effects of W-OH treatment concentration and water content on tensile properties,soil suction and microstructure were investigated.The tensile tests reveal that W-OH treatment has a significant impact on the tensile strength and failure mode of the soil,which not only effectively enhances the tensile strength and failure displacement,but also changes the brittle failure behavior into a more ductile quasi-brittle failure behavior.The suction measurements and mercury intrusion porosimetry(MIP)tests show that W-OH treatment can slightly reduce soil suction by affecting skeleton structure and increasing macropores.Combined with the microstructural analysis,it becomes evident that the significant improvement in soil tensile behavior through W-OH treatment is mainly attributed to the W-OH gel's ability to provide additional binding force for bridging and encapsulating the soil particles.Moreover,desiccation tests demonstrate that W-OH treatment can significantly reduce or even inhibit the formation of soil tensile cracking.With the increase of W-OH treatment concentration,the surface crack ratio and total crack length are significantly reduced.This study enhances a fundamental understanding of eco-polymer impacts on soil mechanical properties and provides valuable insight into their potential application for improving soil crack resistance.

Thermo-Mechanical, Physico-Chemical, Morphological, and Fire Characteristics of Eco-Friendly Particleboard Manufactured with Phosphorylated Lignin Addition

Lignin,lignosulfonate,and synthesized phosphorylated lignosulfonate were introduced as greenfillers in citric acid-sucrose adhesives for bonding particleboard fabricated from areca leaf sheath(ALS).The characteristics of particleboards were compared to that of ultralow emitting formaldehyde(ULEF-UF).Thefillers derived from Eucalyptus spp.kraft-lignin were added forflame retardancy enhancement.10%of each lignin and modified lig-nin was added into the ULEF-UF and citric acid-sucrose bonded particleboards.Analyses applied to particle-boards included thermal characteristics,X-ray diffraction analysis(XRD),morphological properties,Fourier transform infrared spectroscopy(FTIR),as well as physical,mechanical,andfire resistance characteristics of the laboratory-fabricated particleboards.Lignin and modified lignin resulted in improved thermal stability of the composites bonded with ULEF-UF while the improvement in the particleboard bonded with citric acid-sucrose was not significant.The introduction offiller exerted a higher influence on the UF-bonded particleboards compared to composites fabricated with citric acid-sucrose.Generally,the presence of lignin,lignosulfonate,and phosphorylated lignosulfonate enhanced the mechanical strength of the ULEF-bonded particleboards,although their dimensional stability has deteriorated.Markedly,the use of lignin and lignosulfonate enhanced thefire resis-tance of the particleboards produced with lower observed weight loss.All laboratory particleboards exhibited satisfactoryfire resistance,attaining a V-0 rating in according to the UL-94 standard.

Atomic-scale engineering of advanced catalytic and energy materials via atomic layer deposition for eco-friendly vehicles

Zero-emission eco-friendly vehicles with partly or fully electric powertrains have exhibited rapidly increased demand for reducing the emissions of air pollutants and improving the energy efficiency. Advanced catalytic and energy materials are essential as the significant portions in the key technologies of eco-friendly vehicles, such as the exhaust emission control system,power lithium ion battery and hydrogen fuel cell. Precise synthesis and surface modification of the functional materials and electrodes are required to satisfy the efficient surface and interface catalysis, as well as rapid electron/ion transport. Atomic layer deposition(ALD), an atomic and close-to-atomic scale manufacturing method, shows unique characteristics of precise thickness control, uniformity and conformality for film deposition, which has emerged as an important technique to design and engineer advanced catalytic and energy materials. This review has summarized recent process of ALD on the controllable preparation and modification of metal and oxide catalysts, as well as lithium ion battery and fuel cell electrodes. The enhanced catalytic and electrochemical performances are discussed with the unique nanostructures prepared by ALD. Recent works on ALD reactors for mass production are highlighted. The challenges involved in the research and development of ALD on the future practical applications are presented, including precursor and deposition process investigation, practical device performance evaluation, large-scale and efficient production, etc.

Eco-friendly physical blowing agent mass loss of bio-based polyurethane rigid foam materials

Through systematical experiment design, the physical blowing agent(PBA) mass loss of bio-based polyurethane rigid foam(PURF)in the foaming process was measured and calculated in this study, and different eco-friendly PBA mass losses were measured quantitatively for the first time. The core of the proposed method is to add water to replace the difference, and this method has a high fault tolerance rate for different foaming forms of foams. The method was proved to be stable and reliable through the standard deviations σ1and σ2for R1(ratio of the PBA mass loss to the material total mass except the PBA) and R2(ratio of the PBA mass loss to the PBA mass in the material total mass) in parallel experiments. It can be used to measure and calculate the actual PBA mass loss in the foaming process of both bio-based and petroleumbased PURF. The results show that the PBA mass loss in PURF with different PBA systems is controlled by its initial mass content of PBA in PU materials ω. The main way for PBA to dissipate into the air is evaporation/escape along the upper surface of foam. This study further reveals the mechanism of PBA mass loss: the evaporation/escape of PBA along the upper surface of foam is a typical diffusion behavior. Its spread power comes from the difference between the chemical potential of PBA in the interface layer and that in the outside air. For a certain PURF system, R1has approximately linear relationship with the initial mass content of PBA in PU materials ω, which can be expressed by the functional relationship R1= kω, where k is a variable related to PBA’s own attributes.

One-step Eco-friendly Fabrication of Antibacterial Polyester Via On-line Amination Reaction by Melt Coextrusion

The work is dedicated to develop a one-step eco-friendly method to prepare antibacterial polyethylene terephthalate(PET).We report a one-step eco-friendly method to manufacture antibacterial PET via on-line amination reaction by melt coextrusion.Beside evenly mixing of poly(hexamethylene guanidine)(PHMG)and PET in the melt coextrusion procedure,the amination reaction also occurred between PHMG and PET under high temperature(230-270℃).The antibacterial ability of composite PET showed obvious PHMG concentration dependence,and antibacterial activity reached more than 99%when PHMG content was 2.5 wt%.Moreover,LIVE/DEAD fluorescence test further confirmed that the composite PET could kill bacteria quickly and efiectively(within 30 min);while negligible cytotoxicity was observed to HSF and HUVEC cells.Onestep eco-friendly fabrication of composite antibacterial PET was accomplished by on-line melt coextrusion.The composite antibacterial PET has potential use in multiple fields to combat with pathogenic including textiles,packaging materials,decoration materials and biomedical devices,etc.

Eco-Friendly Knit Garments Washing Implementation and Its Impact

Environment pollution is one of the major threats to today’s world and researchers say most of the pollution comes from the washing industry.So,the study aims to find out an alternative way to the existing chemical wash process of the washing industry to save the environment.To conduct this study,one knit washing factory has been selected that has eco-friendly wash facilities.The eco-friendly wash process samples have been developed and finally show the comparison in respect of time,per day production and test result to the conventional chemical wash processes along with the impact of production cost on the garment.For all eco-friendly process,it has been found that water consumptions are too less in comparison with conventional process potentials which is partially related to Sustainable Development Goals 13(Climate Action).This study might help to find out a new era of doing washed knitted product business without polluting the environment.

Mayr电弧模型下GIS中快速暂态过电压的仿真分析

SF6气体绝缘封闭组合开关(GIS)中隔离开关进行分合母线时,产生快速暂态过电压(VFTO),幅值高且上升速率极快,威胁GIS及相邻设备的绝缘。选取某800 kV GIS隔离开关分合母线的试验电路为研究对象,采用电磁暂态程序(EMTP/ATP)进行建模仿真,隔离开关燃弧时采用Mayr电弧模型,分析其对VFTO的影响,得出考虑Mayr电弧模型时操作隔离开关、断路器侧隔离开关及变压器侧隔离开关的电压波形,并与考虑时变电阻模型的VFTO进行对比。对VFTO波形进行离散傅里叶分析,得到过电压频率、幅值的变化特征,研究结果为GIS绝缘设计提供参考。

基于多层融合振动数据分析的GIS设备机械缺陷诊断方法研究

气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear,GIS)机械缺陷是导致设备故障的重要因素,针对单测点、单证据机械缺陷诊断模型信息缺失和精度不足问题,该文提出一种多层融合振动数据分析的GIS设备机械缺陷诊断方法。首先,基于真型GIS设备振动模拟平台试验研究测点位置与缺陷类型对振动行为的影响特性;然后,联合统计分析、模态分解、尺度变换方法提出机械振动信号整体与局部信息关注的复合参数分析方法,引入主成分分析开展多测点振动信息的特征层融合降维;最后,提出改进放缩权重的Dempster-Shafer(DS)证据理论和Bagging投票机制的强/弱基学习器决策层融合机制,联合构建多层融合振动数据分析的GIS设备机械缺陷诊断模型。结果表明:不同类型机械缺陷信号的响应幅值、特征频点和畸变程度存在显著差异,复合特征参量大小及分散程度各不相同;同时,测点位置对缺陷信号的复合振动特征参量的表现形式及分布区间也具有一定影响;基于多层融合数据分析的诊断模型实现缺陷有效识别,辨识准确率为98.66%,相比单一分类器诊断效果提升5.83%。该文可为GIS设备机械缺陷诊断方法提供有价值的参考。

GIS多频振动信号产生机理及实验研究

当前国内外对气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear,GIS)的异常振动,尤其是引发振动的激励源、多频振动产生机理等问题缺少实质性研究进展。首先,建立受力模型,研究引发GIS振动的激励源,得到引发分箱型GIS振动的力源值,并指出正常运行状态,三相母线间电动力是主频振动的主要激励源。触头接触不良将导致触头斥力合力增大,地脚螺栓松动将导致系统固有频率的变化,影响非线性振动响应频谱特征;然后,将GIS按照薄壁圆柱壳进行研究,计算GIS壳体多阶固有频率,建立有效的非线性振动方程,首次利用解析方法揭示非线性GIS系统多频振动信号的产生机理;最后,研制成功振动信号采集系统,在550 k VGIS产品上设置典型机械缺陷,经实验验证,系统激发出的振动响应幅值极值点及频率与理论分析结果一致。论文的研究成果可为GIS机械缺陷的检测及诊断提供一定的支持和参考。

基于专家知识与监测数据联合驱动的高压开关柜状态评估

高压开关柜(HVS)作为电力系统的关键设备,对其工作状况进行有效评估可以保障电力系统的安全稳定运行。在工程实践中,由于高压开关柜长期服役于潮湿、高温等恶劣环境下,不可避免的传感器失效或人为因素会导致其设备状态数据存在随机缺失的现象,从而破坏了数据的完整性和可用性,使得对数据质量要求较高的数据驱动方法难以直接用于解决高压开关柜状态评估的问题。为了解决上述问题,研究了一种基于专家知识和监测数据联合驱动的高压开关柜状态评估方法。首先,对高压开关柜系统的内部构成进行了深入分析,并根据区域中设备的功能不同将其分为电缆室、母线室和断路器室三大区域。其次,进一步分析了系统状态、各区域状态及其关键部件状态两两之间的因果关系,从而建立了适用于高压开关柜状态评估的三层贝叶斯网络(BN)拓扑结构。然后,引入专家领域知识设计了适用于高压开关柜系统的3种约束罚函数,并通过求解带有约束的优化问题,改善了不完整数据集下的贝叶斯网络参数估计性能,进而实现了对高压开关柜系统状态的精确评估。最后,在自主设计的10 kV高压开关柜样机上开展了对比验证实验,结果表明,相比于支持向量机(SVM)方法和反向传播(BP)神经网络方法,本文所提方法在状态评估精度上更具优势。

港口高压开关柜局部放电信号自适应小波去噪方法

为了有效抑制港口高压开关柜局部放电实测信号中存在的白噪声,文中提出一种基于小波的自适应阈值去噪算法。首先对小波阈值去噪算法中的阈值选取及阈值函数进行优化,通过添加变量增加算法的适用性和灵活性,并使用改进后的粒子群算法(SPSO)对添加的变量进行最优值求解从而实现小波分解层数、小波阈值和阈值函数的自适应选取;其次对仿真信号与实测信号进行去噪。结果表明:与传统软、硬阈值函数去噪相比,使用文中所提算法去噪后的信号信噪比分别提高了5.31 dB和2.38 dB。由去噪后信号的时域图可以看出,与其他几种算法相比本文提出的算法不仅去噪效果良好,还能极大地保留信号中的有效成分。

Ag表面对SF_(6)初级分解产物氧化反应的影响作用研究

运行经验显示SF_(6)在气体绝缘开关设备(GIS)中的热稳定性低于预期,GIS内部的金属表面可能对SF_(6)初级分解与次级反应具有显著的影响作用,但作用机理尚不明晰。该文基于密度泛函理论获得了O_(2)在Ag表面的解离-吸附构型,并建立了低氟硫化物与Ag表面O原子的反应模型,初步揭示了GIS过热故障状态下SF_(6)初级分解产物在Ag表面的氧化反应机理;基于过渡态理论和反应动力学理论,计算获取了界面反应的能垒和反应速率常数,并与气相反应对比,分别确定了三种低氟硫化物的氧化反应路径及其主要场所,并分析了Ag表面对反应的促进/抑制作用机制。结果显示,Ag表面可显著促进SOF_(4)与SOF_(3)的产生,但不利于SF2的表面氧化反应。

GIS绝缘子金属污秽缺陷不同程度间歇性放电诊断分析研究

针对现场气体绝缘组合电器(GIS)绝缘缺陷局部放电漏报、误报情况频发的问题,利用真型GIS搭建局放多源检测试验平台,开展绝缘子表面金属污秽缺陷间歇性放电试验,采用不同局放检测法研究不同程度间歇性放电特性变化规律。研究结果表明:金属污秽缺陷放电量随着放电时间的延长呈现先升后降的变化趋势;放电时间间隔整体呈现增加的变化趋势;超声检测法和化学检测法无法实现金属污秽间歇性放电的有效感知;由4组50个工频周期特高频(UHF)相位分辨局部放电(PRPD)图谱数据所构成的200个工频周期UHF PRPD图谱中能初步得出间歇性放电分布规律;处于间歇性放电状态的金属污秽缺陷不会逐渐发展演变成击穿放电故障。研究成果对拓展间歇性放电特征的认知及现场对GIS放电缺陷的检测具有重要意义。

基于神经监督决策树算法的多感知GIS局部放电识别

为充分表现并利用GIS缺陷的物理联系引导故障诊断,提高GIS局部放电故障诊断方法的可靠性与可解释性,该文提出神经监督决策树算法(neural supervision decision tree,NSDT)实现GIS局部放电高准确率下的可解释故障诊断。将卷积神经网络最终线性层替换为层次结构,构建诱导层。使用树监督损失函数优化节点代表向量,并通过调整softmax函数抑制层次损失。构建监督层,通过原始神经网络输出向量对诱导层输出进行监督修正,在保留可解释性的基础上,提高识别准确率。通过110 kV声光电多感知GIS平台收集导杆尖端、外壳尖端、高压端沿面3种典型单源缺陷局放数据,并组成3种双源缺陷,测试NSDT方法性能表现。试验结果表明,NSDT多级神经决策结构能够准确地识别GIS局部放电类型,相较于卷积神经网络(convolutional neural network,CNN)等传统深度神经网络识别方法,识别可靠性更高,决策信息更加丰富,可解释性更强。

金属罐体对真空灭弧室内部电场分布的影响

利用真空开断技术以及环保气体绝缘技术开发罐式真空断路器是高压真空断路器的一个重要发展方向。为此,建立了126 kV单断口真空灭弧室以及罐式断路器的电场仿真模型,分别从触头表面电场分布、触头间隙有效击穿面积以及内部电场分布对称性三个方面,探究了布置在金属罐中的真空灭弧室内部电场的变化。结果表明,金属罐体引起真空灭弧室内部动、静两侧的电场分布不对称,出现高电位侧电场强度增大,而低电位侧电场强度减小的情况。针对这一情况,建立等效电路模型,从电路层面分析。结果表明,对地杂散电容增大引起了主屏蔽罩的电位降低。进一步地,通过将主屏蔽罩电位设置为一系列的固定值,研究了主屏蔽罩电位对于真空灭弧室内部电场分布的影响。当控制主屏蔽罩电位相同时,布置在金属罐中的真空灭弧室与单个真空灭弧室相比,两者内部电场分布基本一致,这为罐式断路器中的真空灭弧室内部电场的优化提供了参考。

基于机-热-电多参量信号特征的GIS隔离开关状态评估方法

气体绝缘开关(gas insulated switchgear,GIS)设备中的隔离开关故障往往是机械、热、电气多物理量综合作用的结果,从微小缺陷发展至严重故障的过程中,会产生异常振动、温度、局部放电多种参量信号,同时测量并分析GIS隔离开关的多参量信息对于准确获取其运行状态具有重要意义。文中通过在实体220 kV GIS实验平台上模拟隔离开关最为常见的接触不良缺陷,研究不同接触状态时振动信号、温度变化和局部放电信号的演化规律,获得其与设备状态之间的对应关系,结合健康指数理论和改进层次分析法,提出基于多参量特征的GIS隔离开关综合评估方法。使用该方法开展现场测试,其检查结果与多参量综合评估方法的的分析结果相吻合。文中的研究为GIS隔离开关状态的带电检测提供了一种可行性较高的多参量融合分析新方法。

基于实体GIS设备试验的局部放电光学信号传播特性研究

光测法具有电磁免疫性,特别适用于具有封闭结构的气体绝缘开关设备(gas insulated switchgear, GIS)局部放电检测,但是光信号在传播过程中易因传播距离增加或部件遮挡而快速衰减。为此,基于110 kV实际GIS设备开展局部放电光学信号传播特性试验,研究传播距离和绝缘子遮挡对导杆尖刺缺陷和悬浮电位缺陷局部放电光信号的影响规律。结果表明,随着传播距离的增加:尖刺缺陷检测到光信号最大幅值和放电数均有所衰减,放电谱图变化不大;悬浮缺陷放电光信号幅值明显衰减,放电数不变,放电谱图特征逐渐失去“矩形”特征。此外,当光学信号透过带有通气孔的绝缘子传播时,光学信号明显衰减,且幅值波动较大。

Grindability Evaluation of Ultrasonic Assisted Grinding of Silicon Nitride Ceramic Using Minimum Quantity Lubrication Based SiO_(2)Nanofluid

Minimum quantity Lubrication(MQL)is a sustainable lubrication system that is famous in many machining systems.It involve the spray of an infinitesimal amount of mist-like lubricants during machining processes.The MQL system is affirmed to exhibit an excellent machining performance,and it is highly economical.The nanofluids are understood to exhibit excellent lubricity and heat evacuation capability,compared to pure oil-based MQL system.Studies have shown that the surface quality and amount of energy expended in the grinding operations can be reduced considerably due to the positive effect of these nanofluids.This work presents an experimental study on the tribological performance of SiO_(2)nanofluid during grinding of Si_(3)N_(4)ceramic.The effect different grinding modes and lubrication systems during the grinding operation was also analyzed.Different concentrations of the SiO_(2)nanofluid was manufactured using canola,corn and sunflower oils.The quantitative evaluation of the grinding process was done based on the amount of grinding forces,specific grinding energy,frictional coefficient,and surface integrity.It was found that the canola oil exhibits optimal lubrication performance compared to corn oil,sunflower oil,and traditional lubrication systems.Additionally,the introduction of ultrasonic vibrations with the SiO_(2)nanofluid in MQL system was found to reduce the specific grinding energy,normal grinding forces,tangential grinding forces,and surface roughness by 65%,57%,65%,and 18%respectively.Finally,regression analysis was used to obtain an optimum parameter combinations.The observations from this work will aid the smooth transition towards ecofriendly and sustainable machining of engineering ceramics.