Adaptive modeling and classification of the secondary settling tank

In biological wastewater treatment plants the biomass is separated from the treated wastewater in the secondary settler; thus, efficient operation of the secondary settler is crucial to achieving satisfactory effluent quality in the wastewater treatment process (WWTP). In the present work, system identification and soft-computing techniques were used to formulate a model for predicting the solid volume index (SVI) and classification of the sludge bulking phenomenon in the settler. An adaptive time series model was applied to predict the SVI of the secondary settler; this model uses the recursive least square (RLS) method to update the model parameters. The method for classifying the current state of the secondary settler is based on the strong correlation that was observed between the settler state and the values of the time series model parameters, which enabled the time series model parameters to be used as effective features for monitoring the secondary settler. To classify the current state of the secondary settler, a neural network (NN) was used to classify the adaptive time series model parameters, where a hybrid Genetic Algorithm (GA) was used to decide the number of hidden nodes of the NN classifier. Application of the proposed method to a full-scale WWTP demonstrated the utility of the method for simultaneously predicting the SVI value of the secondary settler and classifying the current state of the settler.     

无N-甲基吡咯烷酮的聚氨酯分散体制备的研究进展

作为制备聚氨酯分散体常用的溶剂,N-甲基吡咯烷酮(NMP)已被欧美颁布的法规标识为有毒,使用受到限制,需要进行替换。本文综述了制备无NMP的聚氨酯分散体的研究进展。     

Basics of analytical methods used for the investigation of interaction mechanism between cements and superplasticizers

In order to better understand the interactions between cements and superplasticizers (high-range water reducers), various analytical methods have traditionally been applied, but some of these methods can introduce significant errors. In this paper the fundamental interaction mechanisms are reviewed and appropriate methods and sample preparation conditions are explained in detail. For superplasticizer adsorption measurements, analysis by size exclusion chromatography is useful in order to avoid the effect of other organic compounds released from cement by the action of the superplasticizer. For BET specific surface area measurements it is important to avoid pre-drying at over 60 °C, as otherwise ettringite can decompose and strongly increase the surface area. In order to evaluate pore solution chemistry correctly the aqueous phase must be extracted without dilution. In addition, the fluidity performance of many cements in superplasticized concretes can be changed simply by passage through a storage silo, for reasons which are not yet understood.     

PP或PE用双组分PU胶粘剂的制备与性能研究

以聚酯多元醇、混合异氰酸酯(MDI/TDI)、扩链剂(1,2-丙二醇)、异氰酸酯固化剂(TMP-TDI)和溶剂(乙酸乙酯)等为主要原料,制备了PP(聚丙烯)、PE(聚乙烯)粘接用双组分PU(聚氨酯)胶粘剂。研究结果表明:当m(结晶性聚酯多元醇)∶m(非结晶性聚酯多元醇)=80∶20~60∶40、R=n(-NCO)/n(-OH)=0.95~0.97、m(MDI)∶m(TDI)=90∶10~60∶40和w(功能性聚酯多元醇XCP-2325)=2%时,PU预聚体的相对分子质量为(9~11)×104,其常温固化12 h后的邵A硬度(76)有利于PU预聚体的破碎;当PU预聚体/乙酸乙酯溶液的固含量为12%时,双组分PU胶粘剂的操作性能(黏度为22 mPa.s)、180°剥离强度(初始2.3 N/25 mm、最终41.0 N/25 mm)俱佳。     

有机硅改性丙烯酸酯PSA的制备方法及应用研究进展

简述了有机硅改性丙烯酸酯PSA(压敏胶)的常用改性方法,重点介绍了乳液聚合、种子核/壳聚合和溶液聚合等方法;然后对丙烯酸酯PSA的应用领域(如医用领域等)进行了介绍。最后,对有机硅改性丙烯酸酯PSA的应用前景作了展望。     

铝塑复合板用热熔胶的制备及性能研究

以过氧化二异丙苯(DCP)为引发剂、马来酸酐(MAH)为接枝改性单体和聚乙烯(PE)为主要原料,采用熔融挤出法制备了铝塑复合板用PE-g-MAH(聚乙烯接枝马来酸酐)基HMA(热熔胶),并着重探讨了DCP和MAH含量对PE-g-MAH的接枝效率和粘接性能等影响。结果表明:在试验范围内,PE-g-MAH的接枝效率(y)与DCP含量(x1)或MAH含量(x2)之间的关系符合y=28.03x1+1.49或y=0.73x2+10.65的线性关系;当w(DCP)=0.44%、w(MAH)=2%时,PE-g-MAH基HMA的粘接性能相对最好,其剪切强度(6.10 MPa)高于杜邦HMA(4.26 MPa),并且其接枝效率为12.91%。     

两种计算选煤设备实际产率的方法与比较

介绍了2种计算实际产率的方法——格式法和规划求解法在评定三产品重介质旋流器工艺性能上的应用,比较了2种方法的优异。     

Influence of the preparation on the mechanical,thermal, and gas permeation properties of polypropylene/oligopinene thin films

The mechanical, thermal, and gas permeation properties of polypropylene (PP)/oligopinene systems in the form of compression thin films 10 μm thick, which were prepared by quenching (with liquid nitrogen) and slow‐cooling (15°C/min) techniques, were examined. The addition of oligopinene to PP changed the stress–strain curve of the polyolefin. Both for quenching and slow‐cooling films, with a higher oligomer content, no more yielding was observed, and the elongation at break abruptly decreased with greater than 10% oligomer. The elastic modulus and stress at break changed according to the thermal conditions of the film preparation. Thermal analysis revealed that the blend system had two glass‐transition temperatures for both types of films. The values of permeation to CO₂ were independent of the film preparation and were practically unchangeable with the oligomer content in the blends, indicating that the overall decrease in the crystallinity was counterbalanced by the rigidity of the two amorphous phases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2253–2260, 2003     

重组人乳头瘤病毒疫苗免疫原性检测方法的比较

目的评价重组人乳头瘤病毒(human papillomavirus,HPV)疫苗免疫原性2种检测方法的相关性。方法应用间接酶联免疫吸附(ELISA)法和假病毒中和(pseudovirion-based neutralization assay,PBNS)法对26份阴性血清样本、34份自然感染HPV16或HPV18的血清样本及30份接种HPV16/18型双价疫苗后7个月的血清样本进行抗体滴度检测,并采用Pearman进行相关性分析。结果 3组样本的抗HPV16型和HPV18型抗体滴度的2次检测结果比值显示,试验室内重复性较好;2种方法检测血清样本抗HPV16型抗体滴度的总体相关系数为0.826,抗HPV18型为0.921;自然感染HPV的血清样本抗HPV16型抗体滴度的相关系数为0.519,抗HPV18型为0.613;接种HPV16/18型双价疫苗后的血清样本抗HPV16型抗体滴度的相关系数为0.671,抗HPV18型为0.879。结论间接ELISA法和PBNS法在检测血清样本中抗HPV16/18型抗体滴度时均具有较好的重复性和相关性,其中以接种疫苗后的血清样本中抗体滴度相关性最佳,为HPV疫苗免疫原性的检测及剂量探索试验提供了参考依据。     

Measurement methods of carbonation profiles in concrete: Thermogravimetry, chemical analysis and gammadensimetry

This paper deals with two experimental methods to determine carbonation profiles in concrete. Gammadensimetry is a non-destructive test method able to measure the total penetrated CO₂ and to monitor the carbonation process during laboratory accelerated tests. The second method is thermogravimetric analysis (TGA) supplemented with chemical analysis (CA): as TGA is performed on a small mortar sample not representative of the whole tested concrete, CA is needed to proportion the sample cement content, the sand content and to correct the TGA results becoming thus representative of the concrete mix. Consequently, TGA-CA gives accurate quantitative profiles in carbonated cementitious materials. Results are reported for an ordinary Portland cement paste, and three concrete mixes, containing siliceous or calcareous aggregates. The CO₂ mass loss due to carbonation occurs from 530 to 950 °C, which overlaps the temperature range of the calcareous aggregate dissociation. To solve the problem, the origin of CaCO₃ is carefully analyzed. Calcium carbonate ensuing from C-S-H carbonation dissociates in a lower temperature range than the more stable one ensuing from portlandite carbonation and from limestone, which enables C-S-H carbonation to be distinguished from calcareous aggregates. Therefore, TGA-CA allows the CaCO₃ ensuing from C-S-H carbonation to be measured and to calculate the portlandite degraded by carbonation. Thus, the total calcium carbonates profiles can be deduced even when calcareous aggregates is present in the concrete mix.     

Effect of poly(vinyl chloride) resin type in the preparation process of slush powder

During the preparation of the poly(vinyl chloride) (PVC) slush powder, we found that PVC resins obtained by different polymerization methods affected many properties of slush powder and its products. Two types of commercial PVC resins were used for slush powder preparation: mass poly(vinyl chloride) (M‐PVC) and suspension poly(vinyl chloride) (S‐PVC). We used the Haake rheomix test to characterize the absorption of plasticizers into PVC resins, and the results showed that M‐PVC absorbed the plasticizers more quickly than S‐PVC. The fusion behavior of the two slush powders was studied by the thermal plate test and Haake rheomix test, and the results showed that the slush powder of M‐PVC was easier to fuse than that of S‐PVC. The different properties of the two resins and slush powder could be explained by the morphology, average size, and size distribution. Due to the “skin” of the particles' surfaces, the wider size distribution, and the large size of particles, S‐PVC absorbed the plasticizers more slowly and was more difficult to fuse. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3331–3335, 2002     

A nonconventional method for drying of Pseudomonas aeruginosa and its comparison with conventional methods

In this study, preparation of dried cultures of Pseudomonas aeruginosa using nonconventional drying method, namely, low-temperature low-humidity (LTLH) drying was investigated. The effect of carrier materials (whey protein, corn starch, and trehalose) was examined one at a time and also in combinations (to explore the synergistic effect). The results were compared with those obtained using spray drying and freeze drying in terms of cell survival and dry cell powder yield. The powder samples were analyzed also for morphology, flowability, particle size, and moisture content. In LTLH drying, good cell survival was observed along with high powder yield when compared with that in spray drying. Corn starch showed the highest cell survival (91%) and powder yield (94%, w/w) among the carrier materials employed besides resulting in good cell survival (65%) even after a storage period of 6 months.     

A comparison of local phosphorescence detection and fluid dynamic gauging methods for studying the removal of cohesive fouling layers: Effect of layer roughness

The performance of industrial cleaning in place (CIP) procedures is critically important for food manufacture. CIP has yet to be optimised for many processes, in part since the mechanisms involved in cleaning are not fully understood. Laboratory tests have an important role in guiding industrial trials, and this paper introduces and compares two experimental techniques developed for studying CIP mechanisms: local phosphorescence detection (LPD), and scanning fluid dynamic gauging (sFDG).To illustrate the comparison, each technique is used to investigate the influence of soil topology on the cleaning of pre-gelatinised starch-based layers from stainless steel (SS 316) substrates by aqueous NaOH solutions at ambient temperature. The roughness of the soil surface is varied by incorporating zinc sulphide particles with different particle size distributions (range 1–80 μm) into the starch suspensions. The soil roughness increased with the use of larger particles, increasing the 3D arithmetic mean roughness (S_a) of the dry layers (range 0.37–3.33 μm). Rough layers were cleaned more readily than those containing small inclusions, with a good correlation between the cleaning rates observed during LPD and FDG measurements. The LPD technique, which is an instrumented CIP test, gives a better indication of the cleaning time, while sFDG measurements provide further insight into the removal mechanisms.     

四羟甲基硫酸鏻的合成及测定研究

以黄磷、锌粉、硫酸和甲醛为原料,成功合成了四羟甲基硫酸鏻(THPS),详细探讨了不同合成条件对THPS产率的影响,并通过正交实验确定最佳合成工艺为:黄磷∶锌粉∶硫酸∶甲醛=1∶2.5∶7.5∶5(摩尔比),反应温度为85℃,反应时间为6 h。建立了测定其活性物含量的离子交换法,测得THPS的含量为79.20%。用36%乙酸对产品进行重结晶,成功得到了THPS针状晶体。     

四羟甲基硫酸鳞的合成及测定研究

以黄磷、锌粉、硫酸和甲醛为原料，成功合成了四羟甲基硫酸鳞（THIS），详细探讨了不同合成条件对THIS产率的影响，并通过正交实验确定最佳合成工艺为：黄磷：锌粉：硫酸：甲醛=1：2．5：7．5：5（摩尔比），反应温度为85℃，反应时间为6h。建立了测定其活性物含量的离子交换法，测得THIS的含量为79．20％。用36％乙酸对产品进行重结晶，成功得到了THIS针状晶体。     

Covalent immobilization of antibodies for the preparation of immunoaffinity chromatographic supports

Immunosorbents in immunoaffinity chromatography (IAC) are prepared by immobilizing expensive antibodies without guidelines for ensuring the best coupling efficiencies, and avoiding low binding capacities. Covalent immobilization of antibodies on N-hydroxysuccinimide (NHS)-activated Sepharose 4 Fast Flow resin was optimized using human IgG via full factorial design with incubation times (4, 9, 14, 19 and 24 h), temperatures (4°C and 20°C) and coupling reaction buffers (sodium bicarbonate and triethanolamine). The best coupling efficiency (CE) (83.4 ± 8.7%) was reached with triethanolamine buffer, 14 h and 4°C. Comparison of antibody isotypes (IgG or IgM) by a nested factorial analysis suggested that antibodies in the IgG isotype presents the best coupling efficiency.     

A recursive PLS-based soft sensor for prediction of the melt index during grade change operations in HDPE plant

An empirical model has been developed for the successful prediction of the melt index (MI) during grade change operations in a high density polyethylene plant. To efficiently capture the nonlinearity and grade-changing characteristics of the polymerization process, the plant operation data is treated with the recursive partial least square (RPLS) scheme combined with model output bias updating. In this work two different schemes have been proposed. The first scheme makes use of an arbitrary threshold value which selects one of the two updating methods according to the process requirement so as to minimize the root mean square error (RMSE). In the second scheme, the number of RPLS updating runs is minimized to make the soft sensor time efficient, while reducing, maintaining or normally increasing the RMSE obtained from first scheme up to some extent. These schemes are compared with other techniques to exhibit their superiority. This paper is dedicated to Professor Chang Kyun Choi to celebrate his retirement from the school of chemical and biological engineering of Seoul National University.     

Polymer-supported polymerization. A general technique for the preparation of novel beaded polymer supports

A new technique is described whereby the copolymerization of differentially soluble monomers is carried out after being absorbed onto the beads of a highly swellable dimethylacrylamide prepolymer support. The general applicability of the technique is demonstrated by the preparation of beaded multicomponent resins incorporating (i) styrene, 2-hydroxyethyl methacrylate, and divinylbenzene, (ii) polyethyleneimine crosslinked by 1,4-(dichloromethyl)benzene, and (iii) palladium (Il) coordinated by two or four isonitrile ligands, respectively.     

耐低温SBS热熔压敏胶的研制与应用

以长链高级脂肪酸(H18)、松香和甘油为原料,合成了低软化点、低酸值、低黏度和高透明性的H18改性松香甘油酯;然后以此作为SBS(苯乙烯-丁二烯-苯乙烯热塑性弹性体)基热熔压敏胶(HMPSA)的增黏树脂,探讨了H18改性松香甘油酯含量对HMPSA性能的影响。结果表明:当w(H18改性松香甘油酯)=10%时,HMPSA的环形初粘力、180°剥离强度相对最大,比未改性体系分别增加了54.81%、35.29%;适量的H18改性松香甘油酯可有效降低HMPSA的玻璃化转变温度(T_g)、提高HMPSA的耐寒性。