The electrochemical oxidation of vanillin (VL) in 0.2 M phosphate buffer (PB) solution of pH 6.5 was determined in food samples using an electrochemically polymerized glutamic acid (GA) ...functionalized multiwalled carbon nanotubes (MWCNTs) and graphite (GT) composite paste sensor (CPS). The surface concert and morphology of the sensing materials were examined using field emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) measurements. The electrochemical oxidation kinetics of VL was discussed using parameters like solution pH, potential scan rate, temperature, and accumulation time. The selective electrochemical oxidation of VL was analyzed in the presence of metal ions, organic dyes, and sugars on the surface of the functionalized composite sensor. The modified sensor provided a fine linear dynamic range (0.50–18.0 µM) for the electrochemical oxidation of VL with a low limit of detection (LOD) of 0.0199 µM. The DPV measurement was performed for the analysis of VL in food samples on the surface of the functionalized composite sensor via standard addition method with adequate recoveries. Further, the equipped sensor needs lesser preparation cost and presents good reliability, repeatability, and reproducibility towards the electrochemical oxidation of VL.
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•Poly(glutamic acid) functionalized multi-walled carbon nanotubes and graphite composite sensor was developed.•Developed sensor materials were characterised using FE-SEM, EIS, and CV measurements.•Functionalised nano-composite sensor was more sensitive and selective for vanillin detection.•Equipped composite sensor gives a fine linear dynamic range for the oxidation of vanillin with a low limit of detection.•The modified sensor yields adequate recoveries for vanillin in different food samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The study investigates the thermal pyrolysis of coal and co-pyrolysis of the coal-sawdust blend (100% blend) in a fixed-bed reactor. The pyrolysis od coal and sawdust was performed at 773 K, 823 K, ...and 873 K temperature and 30 K min−1 heating rate under nitrogen purge gas (300 mL min−1). Co-pyrolysis coal and biomass was performed at 50%, 100%, and 200% blends at 873 K temperature. The pyrolysis and co-pyrolysis products such as liquid and gas was analysed and compared. Coal pyrolysis resulted higher coal char generation with negligible yield of liquid and gas compared to sawdust. However, 100% co-pyrolyzed blend resulted in higher oil yield % with the increase in temperature from 773 to 873 K with conversion % at 37.35% at 873 K temperature. It was confirmed that the increase in biomass blending percentage with coal, the conversion % increased to 92.8% for the 200% blend. GC/MS characterization of oil from 100% and 200% blended samples revealed that alkane is the main component along with a remarkable Cp value of 1.094 kJ kg−1 K−1 and 0.271 kJ kg−1 K−1 obtained at 823 K and 873 K reaction temperatures respectively. The pyrolysis oil obtained at 873 K at higher biomass to coal blended condition contained higher aromatic compounds. Certain rare comp compounds such as 1-Methyl cyclopropane methanol, 3, 3’- Thiodipropanol, 3- Trans-(1,1-Dimethylethyl)-4, Cis, Methoxycyclohexane-1-ol, 1, 1 -Dimethyl-1-Sinacyclobutane, Octadecane, 2,2,4,15,17,17-Hexamethyl-7, 12-Bis (3, 5,5-Trimethylhexyl), 1,4:3,6-Dianhydro-Alpha-D-Glucopyranose, Hexacosyl acetate and 1,2-Benzenediol, 4-Methyl- present in the copyrolysis oil was also a significant observation in this study.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This book details the effects of climate variability on small pelagic fish and their ecosystems and fisheries. Particularly abundant in coastal upwelling regions off the west coasts of the Americas ...and Africa, off Japan, and in the NE Atlantic, the stocks of these fish fluctuate greatly over the timescale of decades, with large ecological and economic effects. This book describes the nature and cause of these fluctuations, and their consequences. It outlines results from paleo-oceanographic studies, showing that similar fluctuations have also occurred over the past two millennia. The potential effects of future climate change, both natural and anthropogenic, on stocks and fisheries, are considered. The book concludes by recommending the continued international study and assessment of small pelagic fish in order to best inform management and policy under a changing climate. It is written for research scientists, academics, and policy makers in fisheries, oceanography, and climate change.
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► Ag-doped TiO2 nanofibers and nanoparticles were prepared. ► The temperature has positive impact when the Ag-doped TiO2 is used as nanoparticles. ► The nanofibrous morphology is ...preferred to be used at room temperature. ► The nanofibrous morphology strongly enhances the surface activity.
In this study, the influence of the temperature on the photodegradation process using Ag-doped TiO2 nanostructures was investigated. Two morphologies were used; nanoparticles and nanofibers. The nanofibers were synthesized by electrospinning of a sol–gel consisting of titanium isopropoxide, silver nitrate and poly(vinyl acetate). The silver nitrate amount was changed to produce nanofibers having different silver contents. Typically, sol–gels containing 0.5, 1.0, 1.5, 2.0 and 2.5wt% silver nitrate were utilized. Calcination of the electrospun mats at 700°C led to produce well morphology Ag-doped TiO2 nanofibers for all formulations. The nanoparticles were prepared from the same sol–gels, however, instead of spinning the gels were dried, grinded and sintered at 700°C. Photodegradation under UV irradiation for the rhodamine B at 5, 15, 25, 45 and 55°C were performed. For the nanoparticles, increasing the temperature has positive impact as the best degradation was obtained at 55°C. In contrast to the known influence of the temperature on the chemical reactions, in case of the nanofibrous morphology, the temperature has negative impact as the experimental work indicated that the optimum temperature is 25°C. The observed strange effect of the temperature in case of the nanofibrous morphology indicates instant degradation of the dye molecules in the active zones surrounding the nanofibers. Therefore, the increase of temperature results in increase the kinetic energy of the dye molecules so the molecules escape from the active thin film surrounding the photocatalyst. Overall, this study shows that the nanofibrous morphology strongly enhances the surface activity of the photocatalyst which generates negative influence of the temperature.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Nanofluids are recent nanomaterials with improved thermophysical properties that could enhance the efficiency and reliability of heat transfer systems. Relevant properties for heat transfer ...calculation, thin film flows, droplet impingements or microfluidic are surface tension and wettability. However, to date, the understanding of those properties in nanofluids field is at the beginning compared to transport properties. At this stage, this review focus on the effect of nanoparticles and base fluid nature, temperature, use of surfactant, nanoparticle concentration, size and shape as well on the surface tension and wettability of nanofluids. After the presentation of heat transfer processes involving the influence of surface tension and wettability, this paper is organized according to the nature of the nanoparticles dealing with oxide, carbon-based and metallic nanofluids as well as unusual or less considered nature of nanoparticles. The factors affecting the surface tension of nanofluids are relatively well identified, but concentration and surfactant effects present some inconsistent outcomes. In any case, the dispersion of nanoparticles have an effect on the surface tension of base fluid significantly lower than that on transport properties. Based on results available in the literature and existing empirical correlations, a comprehensive assessment, challenges and future works are suggested.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Hydrogen has recently attracted a lot of attention as a clean as well as sustainable energy source. However, the vast bulk of industrial hydrogen is produced by converting natural gas into hydrogen. ...One of the primary goals of large-scale electrolysis is to find efficient, cost-effective, stable, and many other catalysts capable of producing hydrogen from water with minimal electrical bias. Using readily available electrocatalysts on Earth to facilitate the oxidation of water is one way to get closer to an effective method of splitting water to produce hydrogen. Here in the present work, CuWO4 was coated on the conducting polypyrrole (PPy) polymer via hydrothermal techniques to boost its catalytic performance. The fabricated PPy/CuWO4 composite is then utilized for water splitting to yield hydrogen in addition to oxygen. The PPy is able to raise the CuWO4 Fermi levels are separated, as a result, the PPy/CuWO4 produced a large number of strong and readily accessible charges, which led to the splitting of water into hydrogen, and demonstrated that at a potential of 1.470 V vs. RHE, the current density intended for CuWO4-3/PPY reached 10 mAcm−2, attaining an overpotential of 197 mV, with a Tafel plot slope of about 34.4 mVdec−1, and also with a charge transfer resistance of 2.3Ω for OER. Furthermore, the HER activity also attained lower overpotential (250 mV), with a Tafel slope of 50 mV dec−1 in order to reach a 10 mAcm−2 current density. In addition, the CuWO4 is completely encased by the PPy, facilitating charge transfer, allowing the particles to travel rapidly to the polymer's surface. Hence, this study demonstrates that the highly effective CuWO4-3/PPy nanocomposite is responsible for future energy-related applications.
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•The PPy/CuWO4 is fabricated via hydrothermal technique for hydrogen production.•The fabricated PPy/CuWO4 composite demonstrates a potential of 1.470 V vs. RHE.•The CuWO4-3/PPY attains tafel slope of 34.4 mVdec−1 at 10 mAcm−2.•It also attained lower overpotential 250 mV at 10 mAcm−2 for HER.•The CuWO4-3/PPy nanocomposite shows many future energy related applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The adaptation of bacteria involved in anaerobic ammonium oxidation (anammox) to low temperatures will enable more efficient removal of nitrogen from sewage across seasons. At lower temperatures, ...bacteria typically tune the synthesis of their membrane lipids to promote membrane fluidity. However, such adaptation of anammox bacteria lipids, including unique ladderane phospholipids and especially shorter ladderanes with absent phosphatidyl headgroup, is yet to be described in detail. We investigated the membrane lipids composition (UPLC–HRMS/MS) and dominant anammox populations (16S rRNA gene amplicon sequencing, Fluorescence in situ hybridization) in 14 anammox enrichments cultivated at 10–37 °C. “Candidatus Brocadia” appeared to be the dominant organism in all but two laboratory enrichments of “Ca. Scalindua” and “Ca. Kuenenia”. At lower temperatures, the membranes of all anammox populations were composed of shorter 5-ladderane ester (reduced chain length demonstrated by decreased fraction of C20/(C18 + C20)). This confirmed the previous preliminary evidence on the prominent role of this ladderane fatty acid in low-temperature adaptation. “Ca. Scalindua” and “Ca. Kuenenia” had distinct profile of ladderane lipids compared to “Ca. Brocadia” biomasses with potential implications for adaptability to low temperatures. “Ca. Brocadia” membranes contained a much lower amount of C18 5-ladderane esters than reported in the literature for “Ca. Scalindua” at similar temperature and measured here, suggesting that this could be one of the reasons for the dominance of “Ca. Scalindua” in cold marine environments. Furthermore, we propose additional and yet unreported mechanisms for low-temperature adaptation of anammox bacteria, one of which involves ladderanes with absent phosphatidyl headgroup. In sum, we deepen the understanding of cold anammox physiology by providing for the first time a consistent comparison of anammox-based communities across multiple environments.
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•The survey involved 14 anammox lab enrichments and biomasses from WWTPs.•Dominant anammox populations in WWTPs belonged to the genus “Ca. Brocadia”.•Ladderanes correlated with cultivation temperature and anammox populations.•Promising ladderane adaptation mechanisms were alkyl length, phosphatidyl content.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Because of their ubiquitous industrial usage, dyes are significant water pollutants. Adsorption is an effective method for eliminating colors from tainted water. In the twenty‐first century, ...industrialization is growing at a dizzying rate. During this stage, more noble colors and dyes are used. These hues contribute to a wide range of contaminants, including water, soil, and air pollution. The objective of this report is just to discuss the chemical and bio‐based adsorbents used to remove various types of industrial dyes. Several adsorption isotherm assumptions and mathematical formulations were investigated. The effect of a variety of factors on adsorption phenomena is addressed.
Adsorbents are an efficient way to remove industrial contaminants such as dyes from wastewater. This review focuses on the many types of adsorbents, their applications, isotherms, and the various variables that influence them. The paper also discusses the importance of research in the field of green bio‐sorbents.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this work an affordable, energy-efficient technique to enhance the sensitivity of the laser-induced breakdown spectroscopy technique is presented. This method is based in applying the beam of a ...continuous wave (CW) diode laser into the spot where the focused beam of a pulsed Nd:YAG, high-power laser induces the plasma. With the present set-up the CW beam heats the sample's surface to 300 °C. It was found that pre-heating the target in this way increased the line intensity of both neutrals and ions by a factor of up to 4.5. It was also found that the plasma excitation temperature and the electron density of the heated sample did not differ significantly from those at room temperature. However the amount of ablated material did change significantly when the sample was heated, with the crater in the latter case as much as 8.9 times larger than that obtained at ambient temperature. We conclude that the intensification in the pre-heated-sample case stems not from increased electronic plasma density or temperature but rather from a larger plume size resulting from an increased amount of ablated material when the target is heated.
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•Pre-heating with a low-power diode laser intensifies lines in pulsed-laser ablation•Nd:YAG laser-induced breakdown's emission intensified by pre-heating with a CW laser•The use of a continuous-wave laser enhances LIBS sensitivity by a factor of 2 to 4
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The performance of mortar with different SCMs in sulfate environments were investigated under constant and variable temperature conditions.•Expansion rate, compressive strength, visual inspection, ...XRD, and SEM of mortar in sulfate attack were tested.•Mortar with added silica fume has the best performance in resisting sulfate attack at different temperatures.•Metakaolin is extremely unfavorable to sulfate resistance of cement-based materials under high temperature environment.
Sulfate attack on cement-based materials has been extensively studied, but the effect of temperature variation on the rate of sulphate corrosion needs to be further discussed, especially when the vast majority of concrete structures are long exposed to variable temperature. In this paper, four scenarios, including three constant temperature environments (10 °C, 20 °C, and 40 °C) and one variable temperature environment, are investigated for the temperature effect. Six supplementary cementitious materials (SCMs) were added to the mortar specimens respectively, including fly ash, limestone powder, steel slag powder, metakaolin, silica fume, and blast furnace slag. The mortar specimens were immersed in 5% Na2SO4 solution for 330 days, and the resistance of the specimens to sulfate attack was explored using expansion, compressive strength, visual inspection, X-ray diffraction (XRD), and scanning electron microscope (SEM). The high-temperature environment (40 °C) is highly unfavorable to the mortar with added metakaolin, while the low-temperature environment (10 °C) is harmful for the mortar with added limestone powder. The corrosion damage of mortar with added SCMs is less at high temperature than that at low temperature, such as fly ash, limestone powder and blast furnace slag.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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