β-GLUCAN AND β-GLUCAN SOLUBILASE IN MALTING AND MASHING

During malting the water-insoluble β-glucan of barley is diminished whilst water-soluble gum is little decreased. The amount of β-glucan surviving into malt depends on variety but barleys rich in glucan give malts with high β-glucan levels. The β-glucan content of barley depends on variety and growth site. β-Glucan solubilase survives mashing and catalyses the release of hemicellulose into solution. There is no correlation between the β-glucan content of malt and the amount released into wort. However, barley adjuncts containing high levels of β-glucan give worts rich in β-glucan. β-Glucan dissolution in mashing is dependent on time, temperature, grist particle size and liquor: grist ratio. Use of adjuncts derived from barley contribute relatively more β-glucan in wort, coinciding with reduced rates of wort separation, but these can be increased by using a β-glucanase produced by growing the fungus Trichoderma viride on spent grains.     

Aromatic and aliphatic hydrocarbon balance in electric transformer oils

Laboratory-scale NMR studies of transformer oils reveal the presence of highly branched aliphatic and aromatic hydrocarbons with evidence of proportional balance in both aged and new oils. The primary to secondary proton ratios of aged oils were determined to be approximately 1, whereas the ratio ranged from 1.120 to 1.194 in new oils. Analyses indicate that several transitions in the chemistry of oil components contributed to the observed composite peaks and did not allow the identification of specific compounds beyond their functional groups. Resonances of non-hydrocarbons are observed for concentrations between 2 and 4 ppm, while the aromatic families occur at concentrations between 9 and 6 ppm. No consistent trend is observed between oil aging and the evolution of oil chemical composition. However, the color numbers, 0.50-1.82, increase with the oil age and the direction of color change matches that of increasing turbidity from new (T34 and T44) to old oils (T14 and T24). This implies that turbidity may be a dependable method of indexing the aging of transformer oils.     

Conjugated polymers with regularly spaced m‐phenylene units and post‐polymerization modification to yield stimuli‐responsive materials

Two π‐conjugated polymers featuring main‐chain m‐phenylene linkers as well as iodo substituents were initially prepared. The presence of the iodo functionality allowed for the preparation of six additional polymers from the initial two iodo‐substituted polymers via facile post‐polymerization modification using Sonogashira‐type coupling chemistry. The post‐polymerization modification led to crosslinking, to the incorporation of a pyridyl‐bearing functionality for potential use as a ligand for transition metals or to the introduction of a ferrocenyl substituent as a possible redox‐active unit. The m‐phenylene units were incorporated into the polymer main‐chain structure in order to periodically disrupt conjugation, thereby allowing for more uniformity in the effective conjugation length and thus in absorption and emission profiles. The thermal stability and photophysical properties of all eight polymers, as well as the stimuli‐responsiveness of relevant materials to nitroaromatics and metal ions, are reported. © 2015 Society of Chemical Industry     

Air-surface exchange of polybrominated diphenyl ethers and polychlorinated biphenyls

Air and leaf-litter samples were collected from a rural site in southern Ontario under meteorologically stable conditions in the early spring, prior to bud burst, over a three-day period to measure the simultaneous diurnal variations in polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). PBDEs are used in a wide range of commercial products as flame retardants and are being assessed internationally as potential persistent organic pollutants. Total PBDE concentrations in the air ranged between 88 and 1250 pg m(-3), and were dominated primarily by the lighter congeners PBDEs 17, 28, and 47, and concentrations of total PCBs ranged between 96 and 950 pg m(-3), and were dominated by the lower chlorinated (tri- to tetra-) congeners. Slopes of Clausius-Clapeyron plots indicate that both PCBs and PBDEs are experiencing active air-surface exchange. Fugacities were estimated from concentrations in the air and leaf-litter and suggest near equilibrium conditions. Following the three-day intensive sampling period, 40 air samples were collected at 24-hour intervals in an attempt to evaluate the effect of bud burst on atmospheric concentrations. Total PBDE concentrations in the daily air samples ranged between 10 and 230 pg m(-3), and were dominated by the lighter congeners PBDE 17, 28, and 47, whereas concentrations of total PCBs ranged between 30 and 450 pg m(-3) during this period. It is hypothesized thatthe high PBDE concentrations observed at the beginning of the sampling period are the result of an "early spring pulse" in which PBDEs deposited in the snowpack over the winter are released with snowmelt, resulting in elevated concentrations in the surface and air. Later in the sampling period, following bud burst, PBDE concentrations in air fell to 10 to 20 pg m(-3), possibly due to the high sorption capacity of this freshly emerging foliage compartment.     

The use of artificial neural network (ANN) in dry flue gas desulphurization modelling: Levenberg–Marquardt (LM) and Bayesian regularization (BR) algorithm comparison

This research project aims to investigate the efficacy of artificial neural networks (ANN) in mapping dry flue gas desulphurization (DFGD). Bayesian regularization (BR) and Levenberg–Marquardt (LM) training algorithms were used for DFGD modelling. The input layer feed data contained diatomite to Ca(OH)₂ ratio, hydration time, hydration temperature, sulphation temperature, and inlet gas concentration, while the output layer metadata were sorbent conversion and sulphation responses. The hyperbolic tangent (tansig), sigmoid (logsig), and linear (purelin) activation functions were compared to ascertain the best network learning model. The number of hidden layer cells also varied between 7 and 10, given the existence of multiple output feed data. BR and LM performance evaluation was based on coefficient of determination (R²), root mean square error (RMSE), and mean square error (MSE) mathematical analysis. BR was a superlative training tool compared to LM, with lower RMSE and MSE values. The goodness of fit data for both techniques was close to unity, clarifying that ANN using BR and LM tools can be used to predict DGFD outcome. The shrinking core model was used to analyze the desulphurization reaction and concluding the chemical reaction was the reaction controlling step.     

On-tissue chemical derivatization in mass spectrometry imaging

Mass spectrometry imaging (MSI) combines molecular and spatial information in a valuable tool for a wide range of applications. Matrix-assisted laser desorption/ionization (MALDI) is at the forefront of MSI ionization due to its wide availability and increasing improvement in spatial resolution and analysis speed. However, ionization suppression, low concentrations, and endogenous and methodological interferences cause visualization problems for certain molecules. Chemical derivatization (CD) has proven a viable solution to these issues when applied in mass spectrometry platforms. Chemical tagging of target analytes with larger, precharged moieties aids ionization efficiency and removes analytes from areas of potential isobaric interferences. Here, we address the application of CD on tissue samples for MSI analysis, termed on-tissue chemical derivatization (OTCD). MALDI MSI will remain the focus platform due to its popularity, however, alternative ionization techniques such as liquid extraction surface analysis and desorption electrospray ionization will also be recognized. OTCD reagent selection, application, and optimization methods will be discussed in detail. MSI with OTCD is a powerful tool to study the spatial distribution of poorly ionizable molecules within tissues. Most importantly, the use of OTCD−MSI facilitates the analysis of previously inaccessible biologically relevant molecules through the adaptation of existing CD methods. Though further experimental optimization steps are necessary, the benefits of this technique are extensive.     

A User Prioritisation Algorithm for Horizontal Handover in Dense WLANs

International Journal of Wireless Information Networks - This paper proposes an algorithm that enhances horizontal handover (HO) in dense wireless local area networks (WLANs), which is implemented...     

Investment casting pattern material based on paraffin wax fortified with EVA and filled with PMMA

Paraffin wax-based compounds are utilized as investment casting pattern materials. This study considered the effect of composition variations on the properties of paraffin wax-poly(ethylene-co-vinyl acetate) (EVA) blends filled with poly(methyl methacrylate) (PMMA) microbeads. The EVA addition significantly improved mechanical properties while the PMMA improved the needle penetration hardness. Both polymers increased the melt viscosity of the wax composition. Thermal gravimetric analysis of the pyrolysis behavior showed that the compounds volatilize readily with virtually no residue remaining above 500 °C. The 40/20/40 wax/EVA/PMMA composition offers a balanced property profile with the bending stress approaching 6 MPa, the bending strain at break exceeding 4%, and a melt viscosity of about 12 Pa s at 90 °C. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48774.     

Influence of dissolved oxygen content on the bacteria‐induced ennoblement of stainless steels in seawater and its consequence on the localized corrosion risk

The ennoblement of stainless steel (e.g., the increase of open circuit potential [OCP]) is associated with bacterial colonization. This increases the risk of localized corrosion as the critical pitting/crevice potential can be overcome, especially for lower grade stainless steel. In this study, we assessed the influence of dissolved oxygen content (DOC) on the crevice corrosion of duplex and super duplex stainless steels. In addition, we used DNA amplicon sequencing to identify the bacteria most likely associated with the ennoblement. Above approximately 100 parts per billion (ppb) of dissolved oxygen, the ennoblement of OCP was observed leading to an increased risk of localized corrosion. Below approximately 100 ppb of dissolved oxygen, no ennoblement occurred and the risk of localized corrosion was reduced. We identified certain hydrocarbon‐degrading bacteria whose presence correlated with the ennoblement of super duplex stainless steel at saturated DOC. The role of these bacteria is not clear yet, but their distribution indicates a possible involvement in stainless steel ennoblement in seawater.