基于FPGA的油水界面在线监测系统设计

采用八段电容传感器,以FPGA为采集控制核心,设计并实现了一套油水界面检测系统。该系统采用CAV424和MAX197,配合FPGA,实现油水界面信息的采集。调试结果表明,该系统测量精度高,集成度高及易于升级改造。     

Industry-level changes in microbial contamination on market hog and broiler chicken carcasses between two locations in the slaughter process

Pork and poultry products have been implicated in a substantial proportion of microbial foodborne illnesses such as salmonellosis and campylobacteriosis. Understanding the similarities and differences between the effectiveness of interventions applied during slaughter to the two commodities can help identify opportunities to reduce the risk of foodborne illness. This study uses data from two national surveys and censored data techniques to assess the concentrations of microbial contamination on broiler chickens and market hogs at two points in the slaughter process. Statistical distributions are fitted to estimate the average concentrations of microbial contamination, the variability in these concentrations, and the average reduction in contamination between the two locations for pork and chicken produced in the United States. The concentrations of Salmonella and generic Escherichia coli (GEC) are estimated for hog carcasses; the concentrations of Salmonella, GEC, and Campylobacter are estimated for chicken carcasses. These datasets are also used to study the magnitude of seasonal changes in concentrations of microbial contamination and to demonstrate the potential utility of using the reduction in the average aerobic plate count between the pre-evisceration and post-chill stages of the slaughter process as an indicator of the corresponding reduction in other species of bacteria. The study finds interventions for hog carcasses achieve much larger reductions in contamination than those applied to chicken. However, the variability in the concentration of Salmonella contamination on pork is significantly higher, suggesting an opportunity to decrease risk by ensuring more consistent reductions across the industry. The study also finds, for both commodities, that the log₁₀ reductions in the concentrations of GEC are similar to the log₁₀ reductions in Salmonella, while the log reduction in Campylobacter on chicken was substantially greater than for both GEC and Salmonella. Additional analyses demonstrate modest seasonal increases in contamination only on hog carcasses as well as demonstrating that reductions in APC are indicative of reductions in all other organisms, suggesting its potential as an effective indicator organism.     

A comparison of microbial contamination on sheep/goat carcasses in a modern Indian abattoir and traditional meat shops

The microbial load on sheep/goat carcasses was investigated in Deonar abattoir and traditional meat shops in Mumbai. A total of 96 swab samples from carcass sites were collected and analysed from the abattoir, while 144 swab samples from carcass sites were analysed from three meat shops. These samples were processed for total viable count (TVC) and differential counts. The average TVC after flaying, evisceration and washing in the abattoir was 5.51 ± 0.36, 6.06 ± 0.53 and 5.13 ± 0.58 CFU/cm², respectively. Pooled average TVC in the shops after flaying, evisceration and washing was 5.83 ± 0.42, 6.48 ± 0.27 and 6.17 ± 0.41 log CFU/cm², respectively. Statistical analysis revealed a highly significant difference (P < 0.01) among TVC counts after washing between abattoir and the shops. The highest prevalence of Micrococcus spp. and S. epidermidis was noticed during various operations in both the abattoir and the shops. Although Salmonella spp. could not be isolated from any of the carcass sites in the abattoir, in the shops it showed 16.4% prevalence at all the sites irrespective of operations. Overall study revealed that level of contamination in the traditional meat shops was significantly higher compared to the abattoir. However, the microbial contamination in the abattoir is also high if we compare these results to the reports from developed countries and do not conform to EU specifications. The findings of this study reflect the hygiene status of meat production in the developing world.     

Antibacterial activity of decontamination treatments for cattle hides and beef carcasses

There is increasing interest in effective decontamination treatments because healthy food-producing animals can harbor food-borne pathogens and complete prevention of contamination during slaughter can hardly be warranted. Thus we reviewed the available literature and appraised the antibacterial activity of physical, chemical and biological interventions applied on cattle hides and beef carcasses. Based on the evaluated studies, the efficacy of water sprayings, organic acids and their combinations was most frequently investigated for the decontamination of cattle hides and beef carcasses. Most data originated from laboratory-based studies using inoculated samples and extrapolation of these results to commercial practices is restricted. Application of interventions at slaughter plants reduced the bacterial loads on hides and carcasses to some extent, but reductions were clearly lower than those obtained under laboratory conditions. Thus hot water, steam, acetic acid or lactic acid treatment mainly yielded bacterial reductions below two orders of magnitude on carcasses. Under commercial conditions, the use of multiple sequential interventions at different points during slaughter must also be considered in order to enhance the microbiological safety of carcasses. On the other hand, decontamination treatments always must be considered part of an integral food safety system.     

油田注水机组状态在线监测及预测系统的研制

阐述了油田注水机组状态在线监测及预测系统的工作原理与核心结构。介绍了该系统的软件设计。系统采用基于神经网络的专家系统进行趋势预测分析及人工智能预知维护系统进行判别决策的方法 ,实现了对注水机组状态的自动在线判断和故障预报。该系统在油田现场工业实践验证和应用表明 ,既避免了机组恶性事故的发生 ,又有利于改变传统的定期维护方式 ,延长了机组的平均工作周期。     

Reducing microbial counts on chicken and turkey carcasses using lactic acid

A 4% concentration of lactic acid, buffered to pH = 3.7, was applied by spraying directly after the inside-outside washer of a commercial chicken and a turkey production line with the aim of reducing microbial counts on the carcasses. Slight paling of the skin and slight greying of the leaf fat was observed on the carcasses but this was considered to be commercially acceptable. Microbial reductions varied with length of storage after killing, and after treatment with acid. For both chicken and turkey, there was a highly significant difference (p < 0.001) in aerobic plate counts between control and treated carcasses up to Day 9, but no difference on Days 13 and 16. The largest difference between the aerobic plate counts on control and treated carcasses was 2.1 log₁₀ cfu/g on chicken (Day 6) and 1.1 log₁₀ cfu/g on turkey (Day 9). The prevalence of Campylobacter on turkey carcasses on the day after slaughter was reduced significantly (p < 0.001) by the application of the acid. The results indicate that the application of lactic acid offers a method of reducing microbial counts on poultry and may have implications for shelf life and food safety.     

Prevalence and quantification of Campylobacter contamination on raw chicken carcasses for retail sale in China

The quantitative contamination load of Campylobacter on raw chicken carcasses at retail outlets in seven provinces and cities of China was determined. A total of 1587 carcasses over 12 consecutive months were sampled. The overall Campylobacter contamination rate was 45.1% and 19.8% of contaminated carcasses was higher in the load than 3.0 log₁₀CFU/g. The median load was 2.1 log₁₀CFU/g with 1.4 log₁₀CFU/g as the 25th percentile and 2.9 log₁₀CFU/g as the 75th percentile, respectively. Using logistic regression, it observed the significant provincial and monthly variations in prevalence, freshly slaughtered chicken carcasses (63.1%) were found to be 2.3 times higher compared to chilled carcasses (32.9%), while no statistical significance was observed in prevalence among chicken carcasses that had various packaging solution (P = 0.370) nor from different market types (P = 0.680) suggesting that possible cross-contamination had occurred during processing and transportation. The present study found that 52.1%, 59.9%, 2.9%, 8.8% and 8.3% of carcasses were contaminated with C. jejuni, C. coli, C. lari, C. fetus, and C. upsaliensis, respectively. A higher proportion of C. coli (45.4%) than C. jejuni (39.5%) were cultured from the contaminated carcasses and this finding was suggestive of a high degree of cross-contamination occurred not just among poultry products, but also with pork products before/at retail points in China. This study provided quantitative data suitable for a risk assessment model designed to evaluate useful intervention methods to facilitate a reduction in the risk of campylobacteriosis arising from the consumption of contaminated domestically produced chicken meat in China.     

往复压缩机在线状态监测和故障诊断系统的研究

针对往复压缩机的故障特征,开发了往复压缩机在线状态监测和故障诊断系统,压缩机的状态参数汽缸内的工作压力、工作温度、振动、转速、活塞杆下移等可以进行在线监测和通过网络进行远距离传输。     

A multi-sampling approach to evaluate an infrared surface treatment for reducing Listeria monocytogenes contamination on whole Gorgonzola cheese rinds

The microbial ecology of Gorgonzola cheese rind is the focus of many studies because the surface can be contaminated by pathogenic microorganisms. Among food-borne pathogens, particular attention is focused on the behaviour of Listeria monocytogenes that is able to grow at refrigeration temperatures and it could also grow during ripening. The Consortium for the Protection of Gorgonzola Cheese declares the rind not edible but the pathogen may also be transferred during cutting and portioning. Therefore, the decontamination of rinds is important to increasing cheese safety. To achieve this goal, many different strategies have been proposed. In this study, the application of an infrared surface treatment to decontaminate cheese rinds is proposed. The presence of L. monocytogenes, which was artificially inoculated in cheese rinds together with cheese rind microflora, and the cheese rind microflora were monitored before and after the treatment of 32 samples of Gorgonzola cheese rinds.The infrared surface treatment provided good reduction of the rind microflora, and L. monocytogenes was particularly affected by this. The treatment, applied to cheeses at the end of ripening, does not interfere with the ripening process and offers the advantages of short time exposures and easy installation of the equipment in cheese plants. Moreover, this study demonstrated that the sampling method affects the detection of cheese rind microflora. In fact, a non-destructive sampling method, based on a sponge and often used for surface sampling but never before applied to ready to eat food sampling, was compared with a traditional but destructive method, based on rind scraping. Regarding L. monocytogenes, the sponge method allowed to estimate even only 5.71 ± 0.79 log cfu g⁻¹ of cells reduction after the treatment while the higher reduction when considering the rind scraping method was 4.06 ± 3.38 log cfu g⁻¹. The sponge method, combined with the classic scraping one, besides offering the great advantage of not being destructive, allowed to differentiate the effect that the treatment has on the microflora located on the surface from those in deeper layers.     

非常态无线硫化氢监测系统的研制与应用

在高含硫化氢的页岩气开采过程中,硫化氢的实时监测尤为重要,非常态情况下如钻井过程中突发硫化氢泄漏事故,极易造成人员中毒,事故井及周围人员需全部撤离并切断井场电源,严重时要对事故井采取非常措施处理.常规硫化氢的监测因非常态情况下井场没有电源而无法正常工作,非常态无线硫化氢监测系统的设计研制有效解决了硫化氢实时监测的问题....     

电气设备接头在线监测技术的选择与应用

本文简要介绍了电气设备在线温度测试的常用手段,针对主要测试手段进行分析,积累实践经验。     

On-package dual sensors label based on pH indicators for real-time monitoring of beef freshness

On-package dual sensors label has been constructed based on two pH indicators, and it has been applied to monitor the beef freshness. The two pH indicators used are methyl red (MR) and bromo cresol purple (BCP). The beef decay could be detected clearly and easily by the dual color indicators, where the MR change from red to yellow, while the BCP change from yellow to purple. The label responses accurately to the beef freshness, in term of its pH change due to the deterioration as shown by both color change at room and chiller temperatures. Similarly with the other parameters, such as the total volatile basic amine (TVBN), total viable count (TVC) and sensory evaluation. These levels were reached at 8 h and 7 days as the threshold of spoilage at room and chiller temperature respectively. Therefore, the label can be used as a simple and practical indicator for freshness monitoring of packaged beef.     

A preliminary study on the development of an easy method for beef freshness using a cyclic voltammetric system

This study was carried out to develop an easy method for beef freshness using a cyclic voltammetric system. Prime graded (USDA) beef loin at 48 h postmortem was cut into pieces 3 cm thick, packaged into commercial plastic zipper bag, and then stored at 4 °C for 0, 3, 6 and 9 days. A commercial cyclic voltammetry and data processing software were used for this study and the interdigitated electrode was fabricated according to semiconductor manufacturing. The homogenated beef was filtered through Whatman No. 1 filter paper and 250 μL of the filtrate was applied on the interdigitated electrode sensor chip for electrochemical detection. Electrochemical signals changed as storage periods increased. The shape of the cyclic voltammogram changed from a roundish curve to a shapely curve. Redox values (V) also increased during storage. Electrochemical signals matched well with lipid oxidation values (Thiobarbituric acid reactive substances: TBARS). A linear relationship between redox value and TBARS was obtained with a correlation factor of 0.957. Thus, the electrochemical signal of a cyclic voltammetric system can be used as an indicator of beef freshness.     

Low contamination of Campylobacter spp. on chicken carcasses in Minas Gerais state,Brazil: Molecular characterization and antimicrobial resistance

Here, we evaluated Campylobacter contamination on chicken carcasses and phenotypic and genotypic profiles of antimicrobial resistance of the isolated strains. A total of 95 of samples were collected from 19 slaughterhouses from Minas Gerais - Brazil, and analyzed by MPN-PCR method. Campylobacter was found in 16.8% of samples with microbial load ranging from 60 to 184 MPN/carcass. All isolates were resistant to at least 5 (31.2%) of the antimicrobials screened using the disk diffusion method. Thr-86-Ile gyrA mutation, bla_OxA-61 and tet(O) genes were found in 95%, 100% and 40% resistant isolates to ciprofloxacin, ampicillin and tetracycline, respectively. Almost all isolates (90%) showed the three genes required to synthesize the CmeABC efflux system. The use of efflux pump inhibitor (PAβN) resulted in a significant reduction in the MICs of antimicrobials (2–128 fold), indicating the importance of efflux systems in conferring antimicrobial resistance. Campylobacter were detected at low concentrations in Brazilian chicken carcasses. However, high-levels of antimicrobial resistance were observed and associated with several mechanisms. This study provides a baseline survey on contamination of Campylobacter in Brazilian chicken carcasses and its antimicrobial resistance, giving support for actions directed at reducing this pathogen in the food chain.     

新型淀粉-纤维素基微生物驱营养体系研究

开发了以淀粉-纤维素为基础的颗粒状本源微生物驱油营养剂,研究了营养剂对菌群的激活过程,并利用不同岩心模型评价了体系的封堵作用与驱油效果,探讨了该营养体系的调驱机理。结果表明,该体系在有氧和无氧条件下均能有效激活本源菌群,主要是烃类氧化菌和发酵细菌。微生物利用营养体系可产生表面活性物质（带C₈-C₁₂ 长链脂肪酸的鼠李糖脂）和生物气（CH₄和CO₂）,对原油有较好的乳化作用。非均质模型驱油结果表明,该体系不仅具有提高洗油效率的作用,同时可大幅提高波及效率,实验条件下可提高采收率12%~20%。现场试验表明,新体系能有效地封堵高渗透层,改变水驱方向,降水增油效果显著,投入产出比达1∶9以上。     

抽油机在线监测及自动控制技术研究与应用

目前抽油机井的自动控制技术仅限于井场范围内自动控制,对于远程监测的控制技术还没有完全实现。为此,研究了抽油机在线监测及自动控制技术,主要包括现场监测系统设计、通讯系统设计和中央监控系统设计。抽油机在线监测及自动控制系统在辽河油田高升采油厂雷家地区共实施35口井,全部实现动液面计算、功图算产、生产动态集中监测、动液面在线监测及智能变频调速,实现了油井实时动态监测,提高了系统运行效率,收到了良好的应用效果。     

催化重整装置风机在线监测系统

催化重整装置风机在线监测系统采用 4个轴瓦温度传感器、 4个加速度传感器、 2个轴位移传感器和RS— 4 85网络 ,通过监控控制仪转换成RS— 2 32信号传送给计算机 ,实现所需参数的显示与控制。系统程序基于WIN95操作平台 ,采用研华Genie 3 0工件软件包组态程序与用户编程相结合 ,全部参数均由计算机控制数据采集电路 ,通过传感器自动采集 ,数据准确 ,速度快。系统可自动显示各种数据和特征曲线的生成、变化过程 ,全部监测信息及时存储 ,可随时或定时打印数据报表和绘制特性曲线 ,提高了监测的准确性和可靠性 ,减轻了工人的劳动强度。     

锅炉在线水质分析系统的应用及设计

阐述了锅炉装置常用在线水质分析系统的分析方法、工作原理及应用场合,论述了在设计在线水质分析系统中如何保证其准确、可靠、稳定运行的设计要点。     

气井水合物实时监测预警系统研究

气井井口温度较低时井筒内易生成水合物,为了避免测试时冻堵井下油管事故的发生,设计了与现场数采设备相配合的实时监测预警系统。以井口附近地面管线监测点实时传输的压力、温度及流量数据为依据,应用井筒多相流理论计算气井沿程压力温度分布,与图解法所形成的天然气水合物P-T图相比较,进而判断是否达到水合物生成条件,并计算可能存在水合物的井段,由此进行报警并采取及时的预防措施。系统中包含了所涉及开井与关井井筒压力温度计算、天然气水合物生成预测、预警预防设置3部分。编制的软件经现场实践可达到实时监测的目的。最后,给出在集成化实时监控下预防气井水合物的对策。     

旋转机械在线状态监测与故障诊断系统开发研究

简要介绍一种旋转机械在线状态监测与故障诊断系统的原理、结构。重点阐述数据采集处理部分的软、硬件实现方法。给出该系统在某炼油厂的一个应用实例。应用该系统可指导大型连续工作机组的故障预防和维修。