Photoalignment dynamics of azo dyes series with different coordination metals

There are many photoaligned azo dyes that can be used for orientation of liquid crystals in various display devices. However, the structure of these compounds needs to be optimized to increase the rate of the process of molecule photoalignment, as well as to spread the application of these compounds. The main coordination metal that presents in the molecules of azo dyes is sodium derivatives. The use of other alkali metals remains an open question. We used quantum‐chemical computation methods and reversible intermolecular bonding model to determine the effect of metal coordination on the velocity of photoalignment. The theoretical predictions were experimentally verified using sodium, potassium, lithium, and cesium salts of the model azo dye synthesized by us. We conclude that potassium azo derivatives are the fastest, ceteris paribus.     

Analyzing the Effects of Hyperthreading on the Performance of Data Management Systems

As information processing applications take greater roles in our everyday life, database management systems (DBMSs) are growing in importance. DBMSs have traditionally exhibited poor cache performance and large memory footprints, therefore performing only at a fraction of their ideal execution and exhibiting low processor utilization. Previous research has studied the memory system of DBMSs on research-based simultaneous multithreading (SMT) processors. Recently, several differences have been noted between the real hyper-threaded architecture implemented by the Intel Pentium 4 and the earlier SMT research architectures. This paper characterizes the performance of a prototype open-source DBMS running TPC-equivalent benchmark queries on an Intel Pentium 4 Hyper-Threading processor. We use hardware counters provided by the Pentium 4 to evaluate the micro-architecture and study the memory system behavior of each query running on the DBMS. Our results show a performance improvement of up to 1.16 in TPC-C-equivalent and 1.26 in TPC-H-equivalent queries due to hyperthreading.     

A framework to explore results in multiple media information aggregated search

On web information exists in the form of text, audio, image, and video objects often referred to multiple media objects. Vertical web search provides the search of multiple media information usually via keyword-based queries. The search results in different media formats usually presented in separate panels/tabs; integration is mostly non-blended. Therefore, results exploration via vertical web search engines require the selection of a source and scrolling of a linear ranked list of results. Relationships in the results presented in separate panels/tabs are mostly not considered. Search aggregations unify results from several vertical web sources via blended integration, but exploration still requires scrolling of a linear ranked list. Multimedia search frameworks provide the exploration of results in different media formats but more focused towards the retrieval issues. We proposed a multiple media information search framework to address issues, particularly in aggregated search. Our search framework provides a mechanism to explore results via non-linear ways. The search framework realized by suggesting a framework architecture design and instantiating a search tool. The effectiveness of blended integration and browsing is measured via precision and click through rate respectively. Search task support in results exploration mechanism measured via task-based evaluation. We also validated the conformance of various search/exploration attributes discussed in the state-of-the-art in our frameworks.     

Effect of Sodium Carbonate on the Cloud Point in Alkyl Ether/Brine Systems: Apparent Relation with Dynamic Interfacial Tension Minimum

The effect of Na₂CO₃ on the cloud point in Na₂CO₃/surfactant/brine was investigated using two series of nonionic surfactants, C₁₃EO _x and C₁₇EO _x . The cloud point, T _cp, was found to decrease linearly with increasing Na₂CO₃ concentration. This was attributed to Na⁺ and particularly to CO₃ ^2?salting-out effect. The slope a = dTcp/d[Na₂CO₃] became more and more negative as the degree of ethoxylation is increased, suggesting that the higher the number of ethylene oxide (EO) groups the stronger is the cloud point depression for a given increment in Na⁺and CO₃ ^2?ions in solution. This was also illustrated by the linear variation of ΔT _cp = T _cp,0 ? T _cp,[Na2CO3] with the surfactant degree of ethoxylation.     

A novel dynamic bayesian network‐based networked process monitoring approach for fault detection,propagation identification,and root cause diagnosis

A novel networked process monitoring, fault propagation identification, and root cause diagnosis approach is developed in this study. First, process network structure is determined from prior process knowledge and analysis. The network model parameters including the conditional probability density functions of different nodes are then estimated from process operating data to characterize the causal relationships among the monitored variables. Subsequently, the Bayesian inference‐based abnormality likelihood index is proposed to detect abnormal events in chemical processes. After the process fault is detected, the novel dynamic Bayesian probability and contribution indices are further developed from the transitional probabilities of monitored variables to identify the major faulty effect variables with significant upsets. With the dynamic Bayesian contribution index, the statistical inference rules are, thus, designed to search for the fault propagation pathways from the downstream backwards to the upstream process. In this way, the ending nodes in the identified propagation pathways can be captured as the root cause variables of process faults. Meanwhile, the identified fault propagation sequence provides an in‐depth understanding as to the interactive effects of faults throughout the processes. The proposed approach is demonstrated using the illustrative continuous stirred tank reactor system and the Tennessee Eastman chemical process with the fault propagation identification results compared against those of the transfer entropy‐based monitoring method. The results show that the novel networked process monitoring and diagnosis approach can accurately detect abnormal events, identify the fault propagation pathways, and diagnose the root cause variables. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2348–2365, 2013     

Review on zirconate-cerate-based electrolytes for proton-conducting solid oxide fuel cell

The performance of low-to-intermediate temperature (400–800?°C) solid oxide fuel cells (SOFCs) depends on the properties of electrolyte used. SOFC performance can be enhanced by replacing electrolyte materials from conventional oxide ion (O^2-) conductors with proton (H⁺) conductors because H⁺ conductors have higher ionic conductivity and theoretical electrical efficiency than O^2- conductors within the target temperature range. Electrolytes based on cerate and/or zirconate have been proposed as potential H⁺ conductors. Cerate-based electrolytes have the highest H⁺ conductivity, but they are chemically and thermally unstable during redox cycles, whereas zirconate-based electrolytes exhibit the opposite properties. Thus, tailoring the properties of cerate and/or zirconate electrolytes by doping with rare-earth metals has become a main concern for many researchers to further improve the ionic conductivity and stability of electrolytes. This article provides an overview on the properties of four types of cerate and/or zirconate electrolytes including cerate-based, zirconate-based, single-doped cerate–zirconate and hybrid-doped cerate–zirconate. The properties of the proton electrolytes such as ionic conductivity, chemical stability and sinterability are also systematically discussed. This review further provides a summary of the performance of SOFCs operated with cerate and/or zirconate proton conductors and the actual potential of these materials as alternative electrolytes for proton-conducting SOFC application.     

Colour and ergonomics: On the selection of a “colour of the year”

The key role of colour in ergonomics has been emphasized by a number of researchers and design professionals. Although several research studies have been published regarding the use of colour in ergonomics, there are still some areas that need to be considered. The issue of deciding a “colour of the year” is an example, which represents a new challenge for researchers in the field of ergonomics. This is of particular interest considering the fact that the nature of research on the selection of a “colour of the year” is generally based on user experience. This paper argues that ergonomics should play a more prominent role in this field to ensure better user experience and performance. This paper highlights specific areas that need further study and development.     

Antioxidants and antiradicals in almond hull and shell (Amygdalus communis L.) as a function of genotype

To compare the antioxidant and antiradical activity of Amygdalus communis L. hulls and shells phenolic extracts in different genotypes, 18 A. communis L. genotypes were selected from those in Qooshchi, Qalgachi, Qovarchin Qale, Najaf Abad, Jamal Abad, Kahriz, Sfahlan of West and East Azerbayjan provinces of Iran in 2007. The fruits of these almonds were collected, their hulls and shells dried, ground and then methanolic extracts prepared from these hulls and shells. Total phenolic content was determined using the Folin–Ciocalteu (F–C) method. The extracts’ reducing power and scavenging capacity for radical nitrite, hydrogen peroxide and superoxide were evaluated. Significant differences were found in phenolic content of hulls and shells among various genotypes, radical scavenging capacity percentage varied significantly among genotypes and their hulls and shells. S₃-7 genotype with the highest phenolic content and antioxidant activity in its hulls represents a valuable genotype for procuring antioxidant phenolic compounds.     

Stabilization of 6H-Hexagonal SrMnO3 Polymorph by Al2O3 insertion

We demonstrate the structural evolution of polymorphic phases in Al₂O₃-inserted SrMnO₃ ceramics synthesized by solid state reaction. While the 4H-hexagonal phase is predominant in pure SrMnO₃ ceramics, a small amount of 6H-hexagonal polymorph is identified in addition to the primary 4H-hexagonal SrMnO₃ and the secondary hexagonal SrAl₂O₄ phases in the as-sintered ceramics, evidenced by x-ray diffraction and subsequent Rietveld refinement analyses. The existence of the 6H-hexagonal SrMnO₃ phase is corroborated using Raman spectroscopy. The chemical compositions and electronic structures of the Al₂O₃-inserted SrMnO₃ compounds are also examined using energy dispersive spectroscopy and x-ray photoelectron spectroscopy, respectively. The first-principles calculations reveal that there is no clear difference between the total energies of 4H- and 6H-hexagonal polymorphs regardless of the presence/absence of Sr and oxygen vacancies. Possible origins are discussed with the estimation of actual strain based on the refined lattice parameter of 6H SrMnO₃.     

Significance of char active surface area for appraising the reactivity of low- and high-temperature chars

Contemporary char reactivity studies have focussed primarily on coal chars prepared under severe (high-temperature) conditions. In this study, the reactivity of chars prepared under mild (low-temperature) conditions has been addressed. A thermogravimetric analysis system (TGA) was used to determine the reactivity of chars in oxidizing atmosphere using isothermal or non-isothermal techniques. Coal chars were prepared in a TGA or in a slow heating rate organic devolatilization reactor (SHRODR) at a temperature range between 500 ° and 950 °C. The chars prepared by mild pyrolysis of coal at 500 °C are shown to be highly reactive. Comparison of reactivities of low- and high-temperature chars shows that the low-temperature chars exhibit higher reactivity than either the parent coals or the high-temperature chars. Correlation between isothermal reactivity results (e.g. time) and non-isothermal reactivity data (e.g. temperature) has been obtained. Hydrogen contents of chars correlate well with the reactivity of the chars. The study confirms the importance of oxygen chemisorption capacity as a significant reactivity parameter for both low- and high-temperature chars. A new approach has been used for calculating the oxygen chemisorption capacity of chars by accounting for the carbon surface sites occupied by hydrogen (and, therefore, these sites were unavailable for oxygen chemisorption). The occupied sites are readily freed during reactivity measurements and thus were available for participation in carbon-oxygen reactions.