Examining topic shifts in content-oriented XML retrieval

Content-oriented XML retrieval systems support access to XML repositories by retrieving, in response to user queries, XML document components (XML elements) instead of whole documents. The retrieved XML elements should not only contain information relevant to the query, but also provide the right level of granularity. In INEX, the INitiative for the Evaluation of XML retrieval, a relevant element is defined to be at the right level of granularity if it is exhaustive and specific to the query. Specificity was specifically introduced to capture how focused an element is on the query (i.e., discusses no other irrelevant topics). To score XML elements according to how exhaustive and specific they are given a query, the content and logical structure of XML documents have been widely used. One source of evidence that has led to promising results with respect to retrieval effectiveness is element length. This work aims at examining a new source of evidence deriving from the semantic decomposition of XML documents. We consider that XML documents can be semantically decomposed through the application of a topic segmentation algorithm. Using the semantic decomposition and the logical structure of XML documents, we propose a new source of evidence, the number of topic shifts in an element, to reflect its relevance and more particularly its specificity. This paper has three research objectives. Firstly, we investigate the characteristics of XML elements reflected by their number of topic shifts. Secondly, we compare topic shifts to element length, by incorporating each of them as a feature in a retrieval setting and examining their effects in estimating the relevance of XML elements given a query. Finally, we use the number of topic shifts as evidence for capturing specificity to provide a focused access to XML repositories.     

Microfibers nanocomposite based on polyacrylonitrile fibers/bismuth oxide nanoparticles as X-ray shielding material

The main focus of the current study was to fabricate fibrous nanocomposite based on polyacrylonitrile (PAN) fibers containing Bi₂O₃ NPs as the X-ray shielding material. Bi₂O₃ NPs were synthesized based on the solid dispersion evaporation method and dispersed into PAN polymer solution with different weight concentrations. The electrospinning technique was used to fabricate nanocomposite. The morphology, surface functional group, wettability, elemental analysis, and X-ray shielding efficacy of the fabricated nanocomposite were thoroughly evaluated. The dimeter of the fibrous nanocomposites containing 10, 20, and 30 wt% Bi₂O₃ NPs were 1.33 ± 0.08, 1.01 ± 0.11, and 1.69 ± 0.32 μm, respectively. EDX elemental analysis showed that NPs were uniformly distributed into/onto the fibers. The X-ray shielding studies showed that the prepared nanocomposites effectively attenuate the intensity of the X-ray. The entrance surface dose for the negative control was 24.10 ± 1.71 mSv and the application of the nanocomposites significantly reduced the entrance surface dose. The results showed NPs concentration-dependent CT number shift as the indication of X-ray protection and the highest value was obtained by 30 wt% NPs. The obtained results implied that the fabricated nanocomposites effectively attenuate the radiation and they could be applied as the X-ray shielding materials.     

Fabrication of polypyrrole composite on perlite zeolite surface and its application for removal of copper from wood and paper factories wastewater

The large volumes of water used in wood and paper industries produce substantial amounts of wastewater. These industries are among the most polluting ones in the world; there are large quantities of heavy metals (copper, iron, zinc, etc.) and dyes in the wastewater of these industries, and this wastewater has high levels of COD and BOD. We studied copper removal from the effluents of a wood and paper factory by using a polypyrrole composite consisting of natural Zeolite coated on Perlite (PPy/Perlite). The experiments were performed in a batch system in which effects of various parameters including pH, contact time, adsorbent dosage, and temperature on adsorption were studied. Moreover, SEM and FTIR were employed to identify the structure of the synthesized adsorbent. Results indicated that the maximum copper removal (95%) happened at pH=6, contact time of 12 minutes, and adsorbent dose of 0.4 g/100 mL of the wastewater. Furthermore, copper adsorption capacity of the PPy/Perlite adsorbent improved with increases in temperature and reached its peak at 40 °C. Values of the thermodynamic variables (ΔS, ΔH, ΔG) indicated that copper adsorption could occur in the temperature range of 293-323 Kelvin, and was spontaneous and endothermic. Equilibrium information in the studied range of the initial concentrations of copper and in the temperature range suitably matched the Freundlich isotherm. Evaluation of experimental information for studying the kinetics of copper adsorption by PPy/Perlite revealed that copper adsorption followed the pseudo-second-order kinetic model.     

Chemically Functionalized Graphene Nanosheets and Their Influence on Thermal Stability,Mechanical, Morphological,and Electrical Properties of Poly(methyl methacrylate)/Poly(ethylene Oxide) Blend

Poly(methyl methacrylate)/poly(ethylene oxide) (90/10) blend containing various contents of functionalized graphene was prepared through solution technique and characterized to investigate the effects of functionalized graphene content on mechanical, thermal, and electrical properties of the nanocomposites. Infrared results revealed the interaction between matrix and functionalized graphene. Electron microscopy images of the nanocomposites exhibited a good dispersion of functionalized graphene nanosheets in the blend. The incorporation of functionalized graphene significantly increased the thermal stability and mechanical properties of poly(methyl methacrylate)/poly(ethylene oxide) blend. At electrical percolation threshold achieved at functionalized graphene loading of 4.27?wt%, the conductivity of the nanocomposites was increased by more than eight orders of magnitude.     

Novel amphiphilic conetworks based on compatibilized NBR/SBR–montmorillonite nanovulcanizates as membranes for dehydrative pervaporation of water–butanol mixtures

Nanocomposite vulcanizates comprising the poorly compatible acrylonitrile butadiene rubber/styrene butadiene rubber blend are homogenized with 20 parts per hundred montmorillonite forms showing various levels of amphiphathicity: slightly hydrophobic (Mont‐25/50) and highly hydrophobic (Mont75/100) as compared to the highly hydrophilic pristine form (Mont‐0). The purpose of the amphiphathicity is to afford simultaneous binding sites for the poorly compatible components. Thus maximum compatibility is reached with either Mont‐75 or Mont‐50 which improves the mechanical properties. Scanning electron microscopy corroborates cocontinuous morphology. Water vapor permeation through sheets/membranes fabricated from these compositions follows best performance with Mont‐25 followed by Mont‐50 while Mont‐75 and Mont‐100 based membranes acquire an organized continuous drop. This highlights the role of organophilicity in dominating the morphology and performance in pervaporation application. Dehydration of butanol is effective using such membranes with superiority for Mont‐25 based membrane. A plausible model for the transport mechanism was proposed and supported by activation energy calculations for the permeation of the individual components and the sorption affinity measurements as well. All these parameters together suggest the arrest of the n‐butanol within the macrmolecular chains of the membranes, favored by its chemical affinity. This allows therefore a passageway for the water to cross to the other side of the membrane through plasticization of the chains and creation of free volumes which is known as solution diffusion mechanism. POLYM. ENG. SCI., 54:1560–1570, 2014. © 2013 Society of Plastics Engineers     

Thermodynamics of peat-, plant-, and soil-derived humic acid sorption on kaolinite

Humic acids (HAs) form coatings on clays and minerals that can play an important role in nutrient and contaminant migration in soil and water. Humic acid-clay mineral interactions are known to be affected by pH and ionic strength, but little attention has been paid to the effects of temperature. In this paper we report the stoichiometry and thermodynamics of interactions of aqueous HAs (isolated from two peats, two soils and a marine alga with a method that removes lipids) with kaolinite clay, Al2Si2O5(OH)4, at seven temperatures from 5.0 to 35.0 degrees C in 0.05 M NaCl at pH 3.5. All the sorption isotherms exhibit consecutive steps ascribed to HA monolayer and bilayer formation, respectively. Site capacity comparisons suggest different HA molecular conformations on kaolinite. Linearly correlated enthalpy and entropy changes for HA sorption point to the importance of hydration and dehydration in the sorption mechanism.     

Ultrasound-assisted extraction of bioactive compounds from <Emphasis Type="Italic">Malva sylvestris</Emphasis> leaves and its comparison with agitated bed extraction technique

The effects of ultrasound-assisted extraction (UAE) variables—namely extraction temperature (40–60 °C), ultrasonic power (50–150 W), and sonication time (40–60 min)—on the extractive value (EV) of bioactive phenolics from Malva sylvestris leaves were investigated and optimized using Response surface methodology. The effects of extraction solvents (ethanol, ethyl acetate, and n-hexane) on EV, free radical scavenging activity (FRSA), total phenolic content (TPC), and major bioactive phenolics were studied using agitated bed extraction (ABE), and the results were compared with the UAE findings. Under the optimal UAE conditions (48 °C, 110.00 W, and 48.77 min) the experimental EV was 279.89 ± 0.21 mg/g with 71.12 ± 0.15% DPPH_sc, 73.35 ± 0.11% ABTS_sc, and a TPC of 152.25 ± 0.14 mg GAE/g. Ethanolic ABE results in higher EV (320.16 ± 0.25 mg g^?1) compared to UAE, while the FRSA and TPC values were reduced. HPLC analysis revealed that the concentration of bioactive phenolics increased significantly (p < 0.05) under the optimal UAE conditions.     

Encapsulation of Orange Essential Oil Using Cross-linked Electrospun Gelatin Nanofibers

The aim of this study was to prepare electrospun gelatin (G) and gelatin-cross-linked tannic acid (GT) nanofibers loaded with orange essential oil. Four G/GT-to-orange essential oil ratios (1:0.25, 1:0.5, 1:0.74, and 1:1) were used to prepare orange oil-loaded nanofibers. The best encapsulation efficiency (69 and 52.6%) and oil content (34.45 and 26.26%) were observed at the ratio of 1:1 for both G and GT, respectively. The morphology and thermal properties of the electrospun fibers as well as the release and storage stability of loaded orange essential oil were investigated at the selected ratio. The results indicated that the fibrous structure of the orange essential oil-loaded samples was maintained. It is found that both G and GT provided suitable controlled release of orange essential oil and were successful in improving its storage stability.     

An analysis of contributing mining factors in coal workers' pneumoconiosis prevalence in the United States coal mines,1986-2018

In the United States,an unexpected and severe increase in coal miners' lung diseases in the late 1990s prompted researchers to investigate the causes of the dis...