Influence of silica gel in production of diacylglycerol via enzymatic glycerolysis of palm olein

Enzymatic glycerolysis was explored in this paper for the production of diacylglycerol (DAG) oils from palm olein. Three commercial enzymes, Lipozyme TL IM, Lipozyme RM IM and Novozym 435 were used for their ability to synthesize DAG in a solvent‐free system. Novozym 435 was found to be the more effective enzyme, resulting in a high DAG production even in the absence of an adsorbent such as silica gel. The yields of DAG were between 43 and 50 wt‐%. Lipozyme TL IM and RM IM, being supported on hydrophilic materials, require an adsorbent to allow slow release of glycerol for reaction with the enzyme and oil. In the absence of silica, no reaction was observed. The success of the reaction is therefore very dependent on the amount of silica used. The yields of DAG using Lipozyme TL IM and RM IM were 52 and 45 wt‐%, respectively. In addition, the degree of reduction in tocopherols and tocotrienols appeared correlated with the efficacy of the glycerolysis reaction. Changes in the slip melting points and solid fat contents of the products are indicative of the reaction occurring.     

An experimentally validated heat and mass transfer model for wax deposition from flowing oil onto a cold surface

A transport model is proposed for wax deposition onto a cold finger from flowing wax-containing oils. The model solves transient energy and mass balances simultaneously for a reversible first-order kinetic rate for precipitation of pseudo-single-component wax, and the effects of yield stress using a critical solid wax concentration to withstand flow-induced stress at the deposit-fluid interface. The model can predict the time evolution of the deposit thickness, and the spatial and temporal evolution of temperature and wax concentration as validated using cold finger experiments. It was found that for high wax content oils, deposit thickness growth is dominated by heat transfer. For low wax content oils that are unable to gel, the thickness growth is slow and accompanied by occasional sloughing. Regardless of the mechanism controlling the growth, mass transfer cannot be neglected as wax diffusion into the deposit continues to take place after the deposit has stopped growing.     

Ohmic contacts to zinc telluride and their high temperature behavior

Ohmic contacts to zinc telluride (ZnTe) have been studied as a function of operating temperature and at room temperature following annealing at 150° C for extended periods of time. Contacts investigated included Ag-diffused, electroless Au, Ag paste, Cu-graphite and electroless Cu-Au. Of these, the Cu-Au contacts improved with annealing and stabilized after 2 hr at 150° C. A copper/gold ratio of 98%/2% yielded a contact resistivity of 0.28 ohm-cm² after stabilizing. Although the other contacts were ohmic, contact resistivity and/or stability was unacceptable.     

Enterprise social media and cyber-slacking: A Kahn’s model perspective

This study investigates the associations between enterprise social media (ESM) use, psychological conditions, and cyber-slacking in the workplace and examines the mediating role of psychological conditions between ESM use and cyber-slacking. The study utilizes Kahn’s framework to develop a research model and investigate various associations, and it employs a cross-sectional design, testing the developed research model with 277 ESM users from Chinese enterprises. The study results suggest that ESM use stimulates various psychological conditions that discourage cyber-slacking behaviors and significantly mediate the associations between ESM use and cyber-slacking.     

Review of technologies for oil and gas produced water treatment

Produced water is the largest waste stream generated in oil and gas industries. It is a mixture of different organic and inorganic compounds. Due to the increasing volume of waste all over the world in the current decade, the outcome and effect of discharging produced water on the environment has lately become a significant issue of environmental concern. Produced water is conventionally treated through different physical, chemical, and biological methods. In offshore platforms because of space constraints, compact physical and chemical systems are used. However, current technologies cannot remove small-suspended oil particles and dissolved elements. Besides, many chemical treatments, whose initial and/or running cost are high and produce hazardous sludge. In onshore facilities, biological pretreatment of oily wastewater can be a cost-effective and environmental friendly method. As high salt concentration and variations of influent characteristics have direct influence on the turbidity of the effluent, it is appropriate to incorporate a physical treatment, e.g., membrane to refine the final effluent. For these reasons, major research efforts in the future could focus on the optimization of current technologies and use of combined physico-chemical and/or biological treatment of produced water in order to comply with reuse and discharge limits.     

Improving the properties of reclaimed waste tire rubber by blending with poly(ethylene‐co‐vinyl acetate) and electron beam irradiation

Scrap rubber reclamation is one of the most desirable approaches to solve the disposal problem of used tires. However, reclaimed tire rubber (RTR) has not gained enough attention due to its poor properties. In this work, the effects of poly(ethylene‐co‐vinyl acetate) (EVA) addition and electron beam (EB) irradiation on the properties of RTR were studied. The RTR/EVA blends containing 100–0 wt % of RTR were prepared in the internal mixer followed by EB irradiation with doses ranging from 50 to 200 kGy. The RTR/EVA blends were subjected to mechanical, gel content, thermal, and morphological analysis. It was found that the addition of EVA to RTR improved the mechanical properties of RTR. However, results revealed that RTR undergoes irradiation‐induced crosslinking in a relatively lesser extent as compared to EVA. This observation is associated with the stabilization and radical scavenging effects of additives, which are present in the RTR matrix. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41649.     

Impacts of different drying strategies on drying characteristics,the retention of bio-active ingredient and colour changes of dried Roselle

The drying kinetics of Roselle(Hibiscus sabdariffa L) of variety Terengganu(UMKL-1) and the quality attribution of Roselle were studied. The experiments were conducted using four different drying methods, including solar greenhouse drying(SD), solar greenhouse with intermittent heat pump drying(SIHP), hot air drying(HA) and heat pump drying(HP). Among the four drying methods, HP achieved the highest drying rate at a range from0.054 g H_2 O·(g DM)~(-1) ·min~(-1) to 0.212 g H_2 O·(g DM)~(-1)·min~(-1) while SD had the lowest drying rate, measured at 0.042 g H_2 O·(g DM)~(-1)·min~(-1).The analysis on colour kinetics revealed that there is no significant colour loss(p 0.05) observed from HP's dried Roselle. Greater amount of flavonoid compounds i.e. protocatechuic acid was found in SD and SIHP dried finished product whereas HP's dried Roselle contains higher percentage of catechin as compared to other drying methods.     

Natural colorant extraction from Cinnamomum camphora tree leaves of different maturities and its ultrasonic‐assisted extraction process

This study investigated natural colorant extraction from camphor tree leaves using a green and effective process. Ethanol, acetic acid, aqueous sodium carbonate and an aqueous solution of cellulase enzyme were used to examine the extraction performance, with and without the assistance of ultrasonics. Results showed that when subjected to changes in frequency and extraction time, ultrasonics is able to accelerate the extraction process and achieve a better yield for chlorophyll and anthocyanin extraction from fresh leaves compared with a traditional heating bath at similar temperatures. However, when an alkaline solvent was used to extract dark brown colorant from the old leaves, a traditional heating bath was found to be more effective than ultrasonic extraction. Cellulase enzyme failed to show its effectiveness in this study when serving as a colorant‐extracting solvent, regardless of the use of ultrasonics.     

The Ambivalent Role of Skin Microbiota and Adrenaline in Wound Healing and the Interplay between Them

After skin injury, wound healing sets into motion a dynamic process to repair and replace devitalized tissues. The healing process can be divided into four overlapping phases: hemostasis, inflammation, proliferation, and maturation. Skin microbiota has been reported to participate in orchestrating the wound healing both in negative and positive ways. Many studies reported that skin microbiota can impose negative and positive effects on the wound. Recent findings have shown that many bacterial species on human skin are able to convert aromatic amino acids into so-called trace amines (TAs) and convert corresponding precursors into dopamine and serotonin, which are all released into the environment. As a stress reaction, wounded epithelial cells release the hormone adrenaline (epinephrine), which activates the β2-adrenergic receptor (β2-AR), impairing the migration ability of keratinocytes and thus re-epithelization. This is where TAs come into play, as they act as antagonists of β2-AR and thus attenuate the effects of adrenaline. The result is that not only TAs but also TA-producing skin bacteria accelerate wound healing. Adrenergic receptors (ARs) play a key role in many physiological and disease-related processes and are expressed in numerous cell types. In this review, we describe the role of ARs in relation to wound healing in keratinocytes, immune cells, fibroblasts, and blood vessels and the possible role of the skin microbiota in wound healing.     

Effect of Binary and Ternary Combination of Metal Salt on Colorimetric and Fastness Characteristics of Acacia Nilotica Dyed Woolen Yarn

ABSTRACT

Acacia nilotica

an important medicinal plant of topical and sub-tropical regions belonging to family Fabaceae of genus Acacia is a source of many active phytochemicals (secondary metabolites) have been explored to study their useful utilization in different fields. The versatile utility of this plant as a source of timber, a source of fodder, tannin, and gum, and fuel has prompted researchers to deepen investigations for full utilization of this plant. To exploit its use as a colorant for textiles, this research study investigates for the first time pre-mordanting of wool with binary and ternary metal salt combinations using aluminum potassium sulfate, ferrous sulfate, and stannous chloride mordants in order to develop natural and beautiful shades on wool with different hue and tone. The dyeing was carried by exhaustion method and dyed samples were analyzed using a reflective spectrophotometer in terms of CIELab and CIELch (L*, a*, b*, c*, and h°) and K/S values. Wash and light fastnesses were investigated according to ISO standards. Wool samples pre-mordanted with ferrous sulfate-stannous chloride (neutral medium) displayed the highest color strength value of 11.22 followed by ferrous sulfate-alum and alum-stannous chloride combinations. Statistical analysis of color parameters confirms the synergetic role of individual metal salts in different combinations. The results showed that 36 different shades having good to very good fastness properties were produced by the use of different metallic salt combinations in the natural dyeing of wool using A. nilotica bark extract as dye.