Dithioester functionalization of poly(cyclohexene oxide) and its application to obtain block copolymers

A new method of introducing dithioester groups into the polymer chain of poly(cyclohexene oxide) is reported. It includes the use of diaryliodonium salt and an aromatic dithioacid as a redox couple to initiate the cationic polymerization of cyclohexene oxide. It was found that the dithioacid by itself cannot start the polymerization of cationic polymerizable monomers; however, in combination with a diaryliodonium salt, an exothermic reaction was produced, yielding a thiocarbonylthio‐functionalized polyether. Thermal profiles of the redox polymerizations were determined by means of optical pyrometry. A preliminary study showed that when the poly(cyclohexene oxide) functionalized with dithioester groups was introduced into the radical polymerization of styrene, the polystyryl growing radicals reacted with the dithioester‐functionalized polyether to form a block polymer. The amount of polyether actually incorporated into the block copolymer was calculated to be 70% of the initial amount of poly(cyclohexene oxide)/dithiobenzoic acid charged into the reactor. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

The Spanish transition to democracy seen through the Spanish database isoc

The study has tried to look at the political transition through the articles published by Spanish scientists in Spanish journals of Social Sciences and Humanities. A sample of 11000 article references from a selected set of 32 journals published from 1976 till 1985, has been the basis of the analysis. This time frame has been divided into two 5 year periods in order to detect any change in the topics published. The result of the analysis has been compared with the “events” as recorded by “El Pais” a very popular newspaper, during the same 10 year period and with a set of specific articles devoted to the Spanish political transition.     

Prediction of maximum recoverable mechanical energy via work integration: A thermodynamic modeling and analysis approach

Thermal energy and mechanical energy are two common forms of energy consumed significantly in the process industries. While thermal energy can be effectively recovered using matured heat integration technologies, recovery of mechanical energy through work integration has not been fully explored. It is shown that work integration can be achieved through synthesizing work exchange networks (WENs), where work exchangers are operated in a batch mode, and compressors and expanders are operated in a continuous mode; this renders network synthesis a very sophisticated design task. It is greatly beneficial if the maximum amount of mechanical energy recoverable by a WEN can be determined prior to network design. In this article, we introduce a thermodynamic modeling and analysis method to identify accurately the maximum amount of recoverable mechanical energy of any process system of interest. The method is rigorous and general for target setting of mechanical energy recovery prior to WEN synthesis. © 2017 American Institute of Chemical Engineers AIChE J, 2017     

LSB split capacitor SAR ADC with 99.2% switching energy reduction

A highly energy efficient capacitor switching technique in a successive approximation register (SAR) analog to digital converter (ADC) for biomedical applications is presented. The proposed scheme based on new switching method, which combine the LSB split capacitive technique and monotonic method can reduce the average switching energy by 99.2% compared to the conventional SAR architecture. Besides reducing energy in each comparison cycle, the suggested method also achieves an 8× reduction in total capacitance used in the digital to analog converter over the conventional one with the same resolution. The proposed ADC can find application in biomedical engineering systems and other fields which low power consumption is needed.     

Some indicators for assessing research performance without citations

The study aims at designing a set of indicators which, integrated altogether, should be albe to inform on the kind of research published in journal articles and its proximity to their specific forefornts. The set of indicators is composed of two subsets, one including information of the authors, research performers indicators, and other embodying information of the references used, source indicators. The source indicators are compared with the references pattern of specific paradigmatic journals used as standard framework of the research field. Three case studies dealing with the Spanish research on Immunology, Neurosciences and Pharmacognosy will be presented. The application of the indicators gave the following results: Spanish Immunology published in foreign journals was basic in its scope while the one published in domestric journals dealt with applied and clinical Medicine. Neuroscience publsiedh in foreign journals by financed Hospitals appertained to the forefront and presented a broad scope, Neuroscience Published in foreign journals by non-financed Hospitals was applied research and Neuroscience published by Universities, also in foreign journals, represented basic research done in a closed system. The case of Spanish Pharmacognosy is more difficult to interpret as three subject fields are involved (Pharmacology, Chemistry and Botany). The indicators did not clearly differentiate between the research published in domestic and foreign journals, although it seems that Spanish scientists are more interested in the pharmacological and botanical aspect of the natural products than in their chemical structure.     

Semantic similarity estimation from multiple ontologies

The estimation of semantic similarity between words is an important task in many language related applications. In the past, several approaches to assess similarity by evaluating the knowledge modelled in an ontology have been proposed. However, in many domains, knowledge is dispersed through several partial and/or overlapping ontologies. Because most previous works on semantic similarity only support a unique input ontology, we propose a method to enable similarity estimation across multiple ontologies. Our method identifies different cases according to which ontology/ies input terms belong. We propose several heuristics to deal with each case, aiming to solve missing values, when partial knowledge is available, and to capture the strongest semantic evidence that results in the most accurate similarity assessment, when dealing with overlapping knowledge. We evaluate and compare our method using several general purpose and biomedical benchmarks of word pairs whose similarity has been assessed by human experts, and several general purpose (WordNet) and biomedical ontologies (SNOMED CT and MeSH). Results show that our method is able to improve the accuracy of similarity estimation in comparison to single ontology approaches and against state of the art related works in multi-ontology similarity assessment.     

Touch fault calculation method on transmission lines stringing on the same tower based on symmetrical coordinate method

In this paper, a touch fault calculation method is proposed based on the symmetric coordinate method. The touch fault in this paper means that a line‐to‐line short circuit fault occurred on parallel transmission lines stringing on a same tower. It is known that the touch fault occurs very rarely such as the galloping phenomena, and it causes an abnormal voltage rise especially on a low‐voltage transmission line. However, a quantitative analysis method of the abnormal voltage has not been proposed. Therefore, a general analysis method of the voltage profile solution for the touch fault is proposed based on the symmetrical coordinate method. The proposed method is able to calculate the precise voltage and current profile solution efficiently by introducing the similar formation for the touch fault solution same as the general fault solution. Demonstrative result to the application in the touch fault calculation is presented in order to verify the practicability of the proposed method.     

Metabolic pathways of the colonic metabolism of flavonoids (flavonols,flavones and flavanones) and phenolic acids

Flavonoids are metabolized by the gut microflora giving rise to a wide range of phenolic acids that may exert systemic effects in the body. Nevertheless, the colonic metabolism pathways and the function of the metabolites formed are poorly studied. In the present study, the individual colonic metabolism of three subclasses of flavonoids (flavonols, flavones and flavanones) and phenolic acids was evaluated. For this, seven standards of flavonoids (quercetin, quercetin–rhamnoside, quercetin–rutinoside, myricetin, luteolin, naringenin and kaempferol–rutinoside) and two phenolic acids (protocatechuic acid and gallic acid) were submitted to an in vitro fermentation model using rat colonic microflora. Simultaneously, a nuts–cocoa cream enriched with these standards of flavonoids was incubated and the colonic metabolism of these compounds was evaluated. The results showed that the greatest number of colonic metabolites came from the fermentation of quercetin and quercetin–rhamnoside, and the maximum concentration of fermentation products was observed after 48 h of fermentation. On the other hand, a smaller number of fermentation products were observed after the colonic fermentation of kaempferol–rutinoside, naringenin, luteolin and myricetin. The phenolic acids were slightly metabolized by the colonic microflora.     

Characterization of aerodynamic performance of wind-lens turbine using high-fidelity CFD simulations

Wind-lens turbines (WLTs) exhibit the prospect of a higher output power and more suitability for urban areas in comparison to bare wind turbines. The wind-lens typically comprises a diffuser shroud coupled with a flange appended to the exit periphery of the shroud. Wind-lenses can boost the velocity of the incoming wind through the turbine rotor owing to the creation of a low-pressure zone downstream the flanged diffuser. In this paper, the aerodynamic performance of the wind-lens is computationally assessed using high-fidelity transient CFD simulations for shrouds with different profiles, aiming to assess the effect of change of some design parameters such as length, area ratio and flange height of the diffuser shroud on the power augmentation. The power coefficient (C_p) is calculated by solving the URANS equations with the aid of the SST k–ω model. Furthermore, comparisons with experimental data for validation are accomplished to prove that the proposed methodology could be able to precisely predict the aerodynamic behavior of the wind-lens turbine. The results affirm that wind-lens with cycloidal profile yield an augmentation of about 58% increase in power coefficient compared to bare wind turbine of the same rotor swept-area. It is also emphasized that diffusers (cycloid type) of small length could achieve a twice increase in power coefficient while maintaining large flange heights.