喷气燃料中微生物污染及检测方法概述

微生物污染会降低燃料品质、影响燃料供给系统正常工作、增加燃料腐蚀性,是影响燃料储存和飞机飞行安全的重要因素。从喷气燃料中的特征微生物、微生物污染的危害和喷气燃料中微生物检测方法三个方面综述了近几年喷气燃料中微生物污染问题研究进展,分析了目前仍然存在的问题,提出了下步研究的重点方向。     

喷气燃料中微生物污染的研究概况

喷气燃料微生物污染会造成严重危害,对于飞行安全和油料储存安全都是巨大威胁。针对喷气燃料中主要微生物(枝孢霉菌和硫酸盐还原菌)、微生物引起的危害、微生物检测方法以及防治措施四个方面进行了介绍,并对喷气燃料中微生物的研究进行了展望。     

浅析航空燃油中的微生物污染

航空燃料微生物污染问题近几年越来越引起关注,由于微生物所引发的事故不断增加,2000年9月IATA工作组新组建了微生物工作组,并召开第一次会议,发表了《IATA微生物污染指南》。在我国,喷气燃料使用过程中也相继发现微生物污染带来的一系列问题,本文就燃料中微生物污染的基本知识加以介绍。     

ATP生物发光法在喷气燃料微生物检测中的应用

近年来,由于微生物污染带来的喷气燃料储存和使用问题日渐增多。喷气燃料中微生物的快速检测是有效治理微生物污染的前提。本文采用HY-LiTE~JET A1燃料试验对ATP生物发光法在喷气燃料微生物检测中的应用进行了研究。研究发现,该方法与国标平皿计数方法在一定范围内呈正相关(R~2=0.960 1),但也存在振荡标准不统一、萃取液萃取不完全、知识产权受限和耗材昂贵等诸多问题。最后展望了ATP生物发光法和滤膜集菌法未来的发展前景,对研制具有我国自主知识产权的喷气燃料微生物检测设备具有指导意义。     

喷气燃料中微生物污染检测方法研究进展

微生物污染对喷气燃料质量的影响极大,受污染的航空喷气燃料会导致飞机油箱金属部件受到腐蚀,飞机燃油系统仪表失灵,发动机过滤器堵塞等事故,影响飞行安全。对现有运用广泛的微生物污染检测方法进行分析、研究,总结各方法的优劣,提出使用各方法的建议。及时发现微生物污染问题,并提出处理建议,保证航空飞行安全。     

喷气燃料中的水分溶解研究

介绍了水在喷气燃料中的三种存在形式以及形成原因,讨论了湿度、温度以及燃料组分等因素对喷气燃料中水分溶解的影响,提出应加强对低温条件下喷气燃料中水分溶解行为的研究,这对提高飞机的飞行安全性能具有重要意义。     

喷气燃料中污染物来源及其危害概述

喷气燃料在加注到飞机油箱中待使用之前都会受到不可避免的污染,其污染物主要包含固体杂质、水、表面活性剂以及微生物。这些污染物会影响燃料的质量,给飞行带来严重的安全隐患,因此加强对其的监测与控制就显得尤为重要。     

温度和水分对3号喷气燃料电导率的影响

电导率是3号喷气燃料检验的一个重要指标,它直接反映了3号喷气燃料的绝缘程度、积聚静电荷及存在静电放电危害程度。在实际工作中经常会发生储存在油罐内的3号喷气燃料电导率发生降低的现象。针对这一现象,从电导率的主要影响因素之中的温度、水分着手进行试验,从而得出了其具体的影响数据,科学地分析了产生这些情况的原因。     

基于颗粒计数的喷气燃料中固体颗粒沉降性研究

喷气燃料中的固体颗粒污染物会增大飞机发动机精密部件磨损,堵塞飞机燃油系统,引发飞行事故。在我国的机场油库,常使用静置沉降法来提高油罐中喷气燃料的洁净性,但其作用效果很难通过目测法或者微孔过滤重量法从颗粒的尺寸大小和数量分布上进行分析。基于此,将基于颗粒计数对喷气燃料中固体颗粒的沉降性进行研究,利用自动颗粒计数器来研究静置沉降对储油罐中喷气燃料的不同尺寸固体颗粒污染物数量变化的影响,从而研究其作用效果。     

3号喷气燃料存储的标准化监控研究

随着我国航空事业的快速发展,喷气燃料作为飞机主要使用能源,其产品工艺和性能参数受到业界人士的重点关注。3号喷气燃料在我国民用航空中得到了广泛应用,为了保证飞机的顺利运行,针对3号燃料的性能指标也提出了更高的要求。但喷气燃料在存储中会随着时间温度变化,燃料性能会逐渐减退,对燃料的正常使用造成严重影响。在文章中,笔者将会对3号喷气燃料存储的标准化监控进行分析,提出一些具体的燃料存储建议。     

反渗透膜微生物污染特性及影响因素研究

通过对反渗透膜微生物污染影响因素的分析,表明进水中有机物含量、细菌总数和SDI值对生物污染的形成影响较大。通过扫描电镜、X射线能谱仪器分析污染膜,表明严重的微生物污染薄膜成网状粘连结构,污染物组成成分主要是碳氧化合物(有机物)以及一定量的镁、硅等结垢物质,可观测到的微生物有球菌、杆菌和霉菌等。     

Electrochemical characterization of anodic biofilm development in a microbial fuel cell

Electrochemical impedance spectroscopy, cyclic voltammetry, and polarization tests were used to monitor the progress of the anode colonization by electrode-reducing microorganisms in a single-chamber membraneless microbial fuel cell seeded with anaerobic sludge. The electrochemical methods showed that an increase in microbial fuel cell power output coincided with a progressive decrease of the anode internal resistance and a more negative open circuit potential. Two redox systems were observed in cyclic voltammograms shortly after microbial fuel cell startup, while a redox system with a peak around ?330 mV (vs. Ag/AgCl) was predominant in the mature biofilm. The redox systems were also dependent on the external resistance chosen for microbial fuel cell operation. This suggests that within the diverse microbial populations several species are capable of electron transfer to the anode, and that the microorganisms with the highest electron transfer rate become predominant. Furthermore, the growth of these electrode-reducing microorganisms can be accelerated by optimizing the microbial fuel cell electrical load.     

微生物方法选择性生产生物燃料的研究进展

目前,工程荫已经广泛应用于食品、药品及酒精燃料等产品的生产中。尽管如此,工程菌发酵技术的潜力仍然没有充分发掘。交通运输业对于耐用燃料的需求日益增强,迫切地需要开发生物燃料的生产技术。为此,科研人员经过几十年的努力,建起了微生物生理学和途径控制学数据库,使得微生物工程成为生物燃料生产的一项理想技术。虽然目前乙醇在生物燃料市场上占有统治地位,但是它在某些物理性质上存在缺陷,并不足一种理想的燃料。回顾了微生物工程的研究进展,综述了一些新型生物燃料的微生物工程生产。     

Studies on the contamination of feed molasses for continuous ethanol production in an immobilised yeast cell reactor

With the present world problem of fossil fuel limitations, alcohol production from renewable resources such as sugar cane molasses, particularly by continuous processes, has become important. In continuous processing, feed contamination problems could become critical. A useful inexpensive technique, which can minimise these problems when molasses is used as the substrate, is to ensure that the time period elapsing after dilution of molasses and before feeding to the reactor is minimal. Experiments were conducted to determine how long the clarified molasses feed solution could be kept under non-sterile conditions without affecting the performance of an immobilised whole cell reactor for alcohol production. For this purpose, the fastest growing contaminant (under the prevailing conditions) present in molasses feed solution was isolated by plating technique. From the initial total number of contaminant microorganisms in the feed solution, and from the experimentally determined generation time of the fastest growing contaminant cells, the safe period of storage of diluted molasses was calculated. This value was in reasonable agreement with the experimental observations.     

微生物燃料电池研究和应用方面的最新进展

微生物燃料电池是一种利用微生物的催化作用将化学能转变为电能的生物装置。微生物燃料电池在作为可替代性能源、新颖的污水处理方法以及氧和污染物的生物传感器等方面具有较大的潜能,但仍需进一步优化。本文确定了限制微生物燃料电池应用操作的几种因素,并在其性能提高方面进行了探讨。     

The influence of residual styrene monomer,benzaldehyde, and microbial activity on the surface properties of polystyrene latices

The influence of residual styrene monomer and benzaldehyde on the surface properties of polystyrene latices has been considered. These materials are commonly found after emulsion polymerisation and their complete removal by dialysis is almost impossible. Steam stripping at reduced pressure (nitrogen atmosphere, < 350K) can be used to remove the last traces of styrene and benzaldehyde from polystyrene, but this process results in some degree of hydrolysis of the surface sulphate groups. Latices are easily contaminated by microorganisms, especially those which are airborne. This can occur during cleaning and/or storage. Microorganisms can survive and multiply in suitable latex environments and can result in the destabilisation and subsequent flocculation of the latex. Controlled experiments with a latex dosed with various levels of a penicillium type fungus demonstrated the possibility that enzymes (classified as aryl sulphate sulphohydrolases - E. C. 3.1.6.1.) were produced which resulted in the rapid hydrolysis of surface sulphate groups. Fungal growth was accompanied by the release of weak acids and metabolites which were titrated in the aqueous phase. Careful consideration should be given to the conditions of latex preparation, cleaning and storage, e.g. use of autoclaved water and γ-irradiation techniques, which will reduce the possibility of microbial contamination. Routine tests for bacteria and fungi should be carried out by plating on microbiological media, since the usual tests for protein such as the Folin-Ciocalteu are insensitive at the low levels of contamination which may be present.     

微生物燃料电池阳极产电微生物研究进展

微生物燃料电池（Microbial fuel cells,简称 MFCs）是一种生物电化学混合系统，利用微生物的氧化代谢作用将有机物或者无机物中的能量转化为电能，具有节能、减少污泥生成及能量转换的突出优势，目前得到研究者们的广泛关注。其中产电微生物是MFCs系统的核心组成部分，筛选及培养高效产电微生物对促进MFCs的产电性能具有重要作用。通过对产电微生物电子传递机制、产电微生物种类以及影响微生物产电的因素进行分析总结，综述了阳极产电微生物的最新研究进展，最后从微生物角度展望了未来的研究方向，以期为产电微生物在MFCs中的应用提供指导和支持。     

Development of the Analysis of Fecal Stanols in the Oyster Crassostrea gigas and Identification of Fecal Contamination in Shellfish Harvesting Areas

The objective of this work was to study the effects of washing and purification steps on qualitative and quantitative analysis of fecal stanols in the oyster Crassostrea gigas using either single or a combination of lipid purification steps on silica gel or aminopropyl bonded silica gel (NH₂) or a washing step. Among the three analytical pathways compared, the two including water extraction or NH₂ purification did not lead to higher recoveries and decreased repeatabilities of extractions compared to the single purification on silica gel. This latter led to similar recoveries (ca. 80 %) and repeatabilities (ca. 10 %) for both spiked standards (coprostanol and sitostanol). This analytical pathway has been applied to oysters collected in a harvesting area in Brittany (France) where fecal contaminations are important and allowed to quantify eight stanols in oysters. The relative proportions of fecal stanols of these oysters were combined with principal component analysis in order to investigate the usefulness of their stanol fingerprints to record a fecal contamination and to distinguish its source between human, porcine and bovine contaminations. Oysters non-fecally contaminated by Escherichia coli did not present specific stanol fingerprints while oysters fecally contaminated had a bovine fingerprint, suggesting a contamination of these samples by bovine sources. As a consequence, the method developed here allows the use of stanol fingerprints of oysters as a microbial source tracking tool that can be applied to shellfish harvesting areas subjected to fecal contaminations in order to identify the different sources of contamination and improve watershed management.     

微生物燃料电池的研究进展

介绍了微生物燃料电池的工作原理。列举了微生物燃料电池的3个实例模型。概括了微生物燃料电池目前存在的问题和解决方法。展望了微生物燃料电池的应用前景。