自动清洗式自然循环蒸发器的试验研究

自然循环自动清洗式蒸发器是解决蒸发器结垢问题的理想方案。其关键是能否在合理的加热温差下产生足够大的自然循环推动力 ,足以带动自动清洗螺旋扭带可靠地自转。为此建立了中试装置进行中试研究。常压蒸发条件下的中试结果表明 :传热温差只有 2 6℃时 ,自然循环推动力可以达到 110 0 0 Pa以上 ,可靠地带动扭带自转实行连续地自动清洗 ,传热系数达 10 %以上 ,能为企业创造相当高的效益 ,并且该技术与现有的蒸发生产的工艺和加热蒸汽压力条件完全相适应     

制盐蒸发器高速自然循环推动力模拟试验

自然循环自动清洗技术是解决制盐蒸发器盐垢问题最理想的方案 ,关键在于能否产生足够大的自然循环推动力。为此进行了自然循环推动力的冷模试验 ,由试验数据分析推算表明 ,蒸发循环液经过加热室后只要上升 3℃以上 ,就可以形成 10 0 0 0Pa以上的自然循环推动力 ,使加热管内的自然循环流速达到 1 0m/s以上 ,满足带动塑料纽带自转清洗的要求。并且 ,蒸发压力愈高 ,自然循环取代强制循环的难度就愈小     

制盐蒸发器高速自然循环推动力模拟试验

自然循环自动清洗技术是解决制盐蒸发器垢问题最理想的方案，关键在于能否产生足够大的自然循环推动力。为此进行了自然循环推动力的冷模试验，由试验数据分析推算表明，蒸发循环液经过加热室后只要上升3℃以上，就可以形成1000pa以上的自然循环推动力，使加热管内的自然循环流速达到1.0m/s以上，满足带动塑料纽带自转清洗的要求。并且，蒸发压力愈高，自然循环取代强制循环的难度就愈小。     

自然循环自动清洗式高效节能蒸发器的核心理论研究

严重影响现有蒸发器效益的焦点是高能耗的强制循环泵和加热面盐垢的周期性停车清洗。自然循环自动清洗式蒸发器能够满意地解决这两个问题 ,为企业创造相当可观的效益。以动力温度概念和不平衡汽化过程机理为基础的自然循环推动力理论研究 ,不仅得到有很大意义的计算模型 ,并且给出了自然循环推动力有效强化的思路 :设计较大截面、足够深度、出口部呈渐扩形的沸腾室来提高汽化的平衡度、降低出口动能损失 ;必须采用安装有像螺旋齿带那样能够低流速下自转、高效强化传热、较低流体阻力的自动清洗元件的短管加热室 ,以便增大动力温度 ,又使自然循环总阻力较低。按此动力学理论设计的自然循环自动清洗式蒸发器顺利地获得中试成功。     

齿带强化传热自然循环蒸发器的优化设计

以斜齿动力学理论为指导、以动力矩强化为目标结构设计的短管加热室,能够在低流速(0.6m/s左右)下实现加热管(Φ38mm×3mm×2000mm或Φ32mm×3mm×2000mm)的自动清洗防垢;传热系数得以成倍强化,循环母液的进出口温度提高值达到自然循环推动力要求的3℃以上,并且阻力在5kPa以下.以自然循环推动力强化为目标进行沸腾室结构设计,自然循环推动力可以达到10kPa以上,足以保证取消强制循环泵后加热室自动清洗防垢的自然循环推动力需要.因此,这种新型结构能够成功地解决蒸发器周期性停车清洗和循环泵高电耗两大问题,实现高产节能高效益.     

椭圆齿扭带加热管自然循环蒸发器结构设计理论

以斜齿动力学理论为指导,以动力矩强化为目标结构设计的短管加热室,能够在低流速(0.6m/s左右)下实现加热管(￠38×3×2000或￠32×3×2000)的自动清洗防垢;传热系数得以成倍强化,循环母液的进出口温差提高值达到自然循环推动力要求的3℃以上,并且阻力在5000Pa以下。以自然循环推动力强化为目标进行沸腾室结构设计,自然循环推动力可以达到1000Pa以上,足以保证取消强制循环泵后加热室自动清洗防垢的自然循环推动力需要。因此,这种新型结构能够成功地解决蒸发器周期性停车清洗和循环泵高电耗两大问题,实现高产、节能、高效益。     

自然循环自动清洗式蒸发器的试验研究

文章中研究的新型蒸发器,加热室内安装有旋流冲推力强化力矩的自动清洗螺旋,能够在低流速、循环总阻力11kPa以下实行自动清洗。沸腾室大截面、大深度、渐扩形出口部,循环母液低流速通过,能够在较大的深度处开始汽化;并且停留时间较长,在加热室得到的显热尽可能多的转化为汽化热;还能大幅度地降低出口动能损失,使自然循环的有效推动力强化达到11kPa～15kPa,从而省去高能耗的强制循环泵。因此新型蒸发器对于传热强化与节能具有很高的价值。     

自然循环自动清洗式蒸发器的试验研究

文章中研究的新型蒸发器，加热室内安装有旋流冲推力强化力矩的自动清洗螺旋，能够在低流速、循环总阻力11kPa以下实行自动清洗。沸腾室大截面、大深度、渐扩形出口部，循环母液低流速通过，能够在较大的深度处开始汽化；并且停留时间较长，在加热室得到的显热尽可能多的转化为汽化热；还能大幅度地降低出口动能损失，使自然循环的有效推动力强化达到11kPa～15kPa，从而省去高能耗的强制循环泵。因此新型蒸发器对于传热强化与节能具有很高的价值。     

自动清洗式蒸发器自然循环推动力的冷模试验

自然循环自动清洗式蒸发器是解决蒸发器结垢问题的理想方案，关键之一是能否产生足够大的自然循环推动力。为此，作者进行了冷态的动力学模拟试验，结果表明经过加热室后相当于水溶液温度升高3℃以上，就能够形成10000Pa以上的自然循环推动力，使加热管内的自然循环流速达到1.0m/s以上，可靠地带动塑料纽带自转，实行连续地自动清洗。     

制盐蒸发器自动清洗技术的可行性试验

盐蒸发器自动清洗技术 ,是由循环流动的蒸发溶液带动加热管内的螺旋扭带旋转来实现的。根据结晶动力学原理 ,采用 Φ2 5 mm× 2 .5 mm× 182 0 mm的碳钢管 ,管内用 Na2 SO4,KCl O3 的冷却过饱和溶液的结晶盐垢进行流体动力学模拟试验。试验结果表明 ,利用螺旋扭带旋转实现自动清洗 ,能够满足一般制盐蒸发器的要求 ,达到长期连续生产的目的 ,并且成本低 ,具有显著的技术经济优势     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press