In‐Line Monitoring and Control of Conversion and Weight‐Average Molecular Weight of Polyurethanes in Solution Step‐Growth Polymerization Based on Near Infrared Spectroscopy and Torquemetry

Summary: It is well known that the weight‐average molecular weight ( ) is strictly dependent on conversion in step‐growth polymerizations performed in batch and that the is very sensitive to impurities and molar imbalance. This makes the work of controlling a non trivial job. In this paper a new methodology is introduced for in‐line monitoring and control of conversion and of polyurethanes produced in solution step‐growth polymerizations, based on near‐infrared spectroscopy (NIRS) and torquemetry. A calibration model based on the PLS method is obtained and validated for monomer conversion, while the weight‐average molecular weight is monitored indirectly with the relative shear signal provided by the agitator. Control procedures are then proposed and implemented experimentally to avoid gelation and allow for maximization of . The proposed monitoring and control procedures can also be applied to other step growth polymerizations.

Proposed control scheme.     

原料油汽化特性对催化裂化反应结焦过程影响的CFD模拟

为考察原料油汽化特性影响,在一套百万吨级工业FCC提升管中,基于多相欧拉模型耦合EMMS曳力和传质、油滴汽化和十二集总反应动力学模型,采用三维CFD模拟研究气液固三相流动、汽化、反应、结焦的复杂过程,新开发结焦预测模型定量预测结焦状况,对比研究不同原料油雾化液滴粒径和起始汽化温度下各相和反应组分浓度场、温度场分布和结焦程度。结果表明,模拟方法可较准确预测汽化、反应生焦和结焦过程,不同雾化液滴粒径和起始汽化温度通过流场分布和汽化快慢影响液相油滴汽化率和反应转化率;合适液滴粒径(60 μm)和起始汽化温度(654 K)可提升轻油、汽油、液化石油气目标产品收率并改善结焦程度。     

In vitro evaluation of the microbial contamination on new toothbrushes: a preliminary study

Objective: The presence and survival of microorganisms on toothbrush bristles might play a role on the etiology of oral infections. The aim of this in vitro study was to evaluate the presence of bacterial contamination on new toothbrushes before oral contact. Materials and methods: Forty toothbrushes from five different manufacturers were used in this experimental study. Each manufacturer was divided according to conventional local of obtaining: industry, drugstore, market, and perfumery. The toothbrush heads were completely immersed into tubes containing 5.0 mL of sterile peptonated water (dilution 1:10). A group of eight tubes containing the sterile solution was used as control. After 21 days of anaerobic incubation, occurrence of contamination was visually evaluated and confirmed by light microscopy. Results: Bacterial growth in the medium, indicative of bristles contamination, was found in a total of 19 out of 40 samples (47.5%) evaluated: 6 out of 14 samples (42.85%) from industry group, 4 out of 8 samples (50.0%) from drugstore, 5 out of 10 samples (50.0%) from market, and 4 out of 8 samples (50.0%) from perfumery. Only the toothbrushes with bristles coated with chlorhexidine did not show contamination. The Gram‐negative sporulating bacilli were the most prevalent form recovered. Conclusions: Except for chlorhexidine group, bacterial growth was observed in all groups evaluated irrespective local of obtaining. Microsc. Res. Tech., 2012. © 2011 Wiley Periodicals, Inc.     

Improving optimum-path forest learning using bag-of-classifiers and confidence measures

Pattern Analysis and Applications - Machine learning techniques have been actively pursued in the last years, mainly due to the great number of applications that make use of some sort of...     

Comparative evaluation of flavonoid content in assessing quality of wild and cultivated vegetables for human consumption

BACKGROUND: Owing to the demand for ‘health foods’, commercial development of wild vegetables may find a sizable market niche if adequate agricultural methods are used to domesticate such species. Available techniques of cultivation (even in traditional farming) may provide many advantages, such as enhancement of the content of active principles in plants and improvement in the quality of the raw material to be processed on an industrial scale. In this context, the flavonoid composition and content of roots and leaves from five varieties of wild herbs (Cichorium intybus, Portulaca oleracea, Tragopogon porrifolius, Urtica dioica and Valerianella eriocarpa) and their cultivated relatives in central Italy were compared. The aims of the study were (i) to reveal the metabolic profile of particular bioactive metabolites present in some unusual food species by using a simple method of analysis, (ii) to quantify and compare the amount of polyphenolic metabolites in wild and cultivated plants and (iii) to evaluate the effect of growing conditions on polyphenolic variability. Data were subjected to statistical analysis. RESULTS: Each herb possessed a specific flavonoid fingerprint as indicated by high‐performance liquid chromatography (HPLC) data. The total phenolic content in cultivated leaves was greater than that in wild leaves for all herbs examined (P < 0.05), with the exception of P. oleracea. CONCLUSION: The results show that the polyphenolic content of the majority of the cultivated herbs (edible parts) is no lower than that of their wild relatives, thus indicating that these species are suitable for cultivation. Copyright © 2007 Society of Chemical Industry     

Reliability allocation methods: A systematic literature review

The choice of a reliability allocation method is not always easy or straightforward, since it depends on several factors. Some factors are directly related to the characteristics of the analyzed system, such as the level of complexity or the reliability configuration; on the other hand, additional aspects constitute boundary conditions, such as budget or experimentation time. In this scenario, the purpose of the present research is to present a systematic literature review on reliability allocation, proposing a guideline to choose the optimal allocation method in respect to the desired application, available resources, and required accuracy. The proposed review analyzes allocation methods in literature, determining main features and area of application. Motivated by a lack of a comprehensive methods summarization present in literature, our research goal is to assist practitioners in choosing a well-suited method and to provide an overview, to support academics in conducting new research in this area. The results of the performed analysis are synthetized according to several criteria. The results are summarized and categorized in different clusters for each individuated application field. The proposed summarization design allows an easy and rapid consultation.     

Is there a ��gender gap�� in authorship of the main Brazilian psychiatric journals at the beginning of the 21st century?

The aim of this study was to investigate the existence of a ??gender gap?? in the authorship of the four most important peer-reviewed psychiatric journals in Brazil and to quantify its magnitude. In addition, we examined the patterns of change in this gap during the period extending from 2001 to 2008 and variations according to the total number of authors, the type of article (original vs. non-original studies), and the journals themselves. A total of 1,036 articles were analyzed. We found that the proportion of female overall participation has increased from 2001 to 2008. Nevertheless, the incremental rate was accounted mostly by the growth of the participation in non-original articles. While the average annual increment for original articles was virtually null (.01%), for the non-original articles the corresponding figure was 3.7%. We also found that the chance of a woman being first author was about three times greater in original papers as compared to non-original ones at the beginning of the study period; this differential declined by 11% per year during this period. A different pattern emerged from the analysis of female last authorship. Year of publication and type of study were still associated with the chance of a woman being the last author but without interaction. Further, the journals themselves were found to be related with female last authorship: the chance of a woman being the last author in an article published in the Revista Brasileira de Psiquiatria was significantly smaller than in the other three journals. Our findings indicate clearly that some progress in being achieved in eliminating the gender gap also in field of Psychiatry and highlight the need for further research in this area.     

RetriBlog: An architecture-centered framework for developing blog crawlers

Blogs have become an important social tool. It allows the users to share their tastes, express their opinions, report news, form groups related to some subject, among others. The information obtained from the blogosphere may be used to create several applications in various fields. However, due to the growing number of blogs posted every day, as well as the dynamicity of the blogosphere, the task of extracting relevant information from the blogs has become difficult and time consuming. In this paper, we use information retrieval and extraction techniques to deal with this problem. Furthermore, as blogs have many variation points is required to provide applications that can be easily adapted. Faced with this scenario, the work proposes RetriBlog, an architecture-centered framework for the development of blog crawlers. Finally, it presents an evaluation of the proposed algorithms and three case studies.