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Although there is enough heat contained in inflowing warm Atlantic Ocean water to melt all Arctic sea ice within a few years, a cold halocline limits upward heat transport from the Atlantic water. The amount of heat that penetrates the halocline to reach the sea ice is not well known, but vertical heat transport through the halocline layer can significantly increase in the presence of double diffusive convection. Such convection can occur when salinity and temperature gradients share the same sign, often resulting in the formation of thermohaline staircases. Staircase structures in the Arctic Ocean have been previously identified and the associated double diffusive convection has been suggested to influence the Arctic Ocean in general and the fate of the Arctic sea ice cover in particular. A central challenge to understanding the role of double diffusive convection in vertical heat transport is one of observation. Here, we use broadband echo sounders to characterize Arctic thermohaline staircases at their full vertical and horizontal resolution over large spatial areas (100 s of kms). In doing so, we offer new insight into the mechanism of thermohaline staircase evolution and scale, and hence fluxes, with implications for understanding ocean mixing processes and ocean-sea ice interactions.

The electrochemical reduction of carbon dioxide is usually studied in aqueous solutions under ambient conditions. However, the main disadvantages of this method are high hydrogen evolution and low faradaic efficiencies of carbon-based products. Supercritical CO 2 (scCO 2 ) can be used as a solvent itself to suppresses hydrogen evolution and tune the carbon-based product yield; however, it has received little attention for this purpose. Therefore, the focus of this study was on the electrochemical reduction of scCO 2 . The conductivity of scCO 2 was increased through the addition of supporting electrolyte and a cosolvent (acetonitrile). Furthermore, the addition of protic solutions of different pH to scCO 2 was investigated. 1 m H 2 SO 4 , trifluoroethanol, H 2 O, KOH, and CsHCO 3 solutions were used to determine the effect on current density, faradaic efficiency, and selectivity of the scCO 2 reduction. The reduction of scCO 2 to methanol and ethanol are reported for the first time. However, methane and ethylene were not observed. Additionally, corrosion of the Cu electrode was noticed., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Bioelectrochemical power-to-gas (BEP2G) is considered a potentially convenient way of storing renewable surplus electricity in the form of methane. In methane-producing bioelectrochemical systems (BESs), carbon dioxide and electrical energy are converted into methane, using electrodes that supply either electrons or hydrogen to methanogenic archaea. This review summarizes the performance of methane-producing BESs in relation to cathode potential, electrode materials, operational strategies, and inoculum. Analysis and estimation of energy input and production rates show that BEP2G may become an attractive alternative for thermochemical methanation, and biochemical methanogenesis. To determine if BEP2G can become a future power-to-gas technology, challenges relating to cathodic energy losses, choice of a suitable electron donor, efficient reactor design/operation, and experience with large reactors need to be overcome., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

High resolution synchrotron x-ray data of near-Bragg diffuse scattering from decagonal Al71.5Ni23Fe5quasicrystals was recorded. A significant dependence on Qbotwas not observed, a dominant phasonic origin can thus be ruled out. An analysis in frame of a TDS theory gives an unlikely ratio of elastic constants c66/c11=4.0. Moreover, subsequent measurements up to 720 K do not reveal a pronounced intensity increase. Predictions of a theory of Huang diffuse scattering, however, nicely match the anisotropy of the measured data. [ABSTRACT FROM AUTHOR]

Micro composites are commonly characterized in bulk. Here we study the temperature triggered release of a bioactive compound from single isolated microcapsules. We monitor the release process in real-time using a novel thermal microscopy method combining laser-induced heating and fluorescence imaging.

This research was designed to evaluate the performance of the CuFe12O19/CuS/Xenon system in the degradation of tetracycline in aqueous solutions. In this study, after green synthesis of nanocomposite using the extract of the Artemisia plant, its properties were determined by XRD, FTIR, FESEM, TEM, BET, XPS, DRS, DLS, EDS, VSM, and PL. In addition, parameters affecting the photocatalytic degradation of tetracycline, including time, pH, TC initial concentration, and nanocomposite dose, were assessed. The findings showed that the degradation efficiency increases with increasing pH and catalyst dosage. Under optimum circumstances (pH = 9, nanocomposite dose of 0.5 g/L, and time 200 min), the process efficiency with concentration of 20 mg/L was 100%. The kinetics of the degradation rate of tetracycline obeyed the pseudo-first-order equation. In addition, the results show that after six consecutive cycles, the synthesized catalyst's ability did not significantly reduce. The results of the mineralization tests revealed that the COD and TOC degradation of the synthetic solution of tetracycline with a concentration of 20 mg/L reached 87.25% and 73.06%, respectively, in the optimal reaction conditions. The scavenger experiments confirmed that OH plays the most crucial role in the decomposition process of tetracycline. Generally, the CuFe12O19/CuS/Xenon photocatalytic system can effectively degradation tetracycline from aqueous environments. [ABSTRACT FROM AUTHOR]

Conventional leather chromium tanning requires long process time, excessive water usage and results in low float exhaustion of chrome salts. Our study aimed to eliminate the negative aspects of chromium tanning by designing a vacuum operated reaction vessel/drum and suitable production recipe for sheepskins. Tanning time decreased from 10 h to 6 h under vacuum. Float uptake was increased almost 30% according to the chrome oxide (Cr2O3) contents in leather and residual floats. Using the process water was also considerably saved. Process success was proved with Cr2O3 contents in leather and wastewater by chemical analyses after tanning operations. Shrinkage temperature (Ts) controls as hydrothermal stability indicator of collagen were also realized on the tanned skins. Pollution loads of conventional and vacuum operated chromium tanning were discussed with chemical oxygen demand (COD), total suspended solids (TSS), conductivity and salinity in the tanning baths. Physico-mechanical properties were also compared of the final products by tensile strength and tear load analyses. The results showed that vacuum operated chromium tanning was highly effective and promised for the sustainable production of leather products. [ABSTRACT FROM AUTHOR]

Globally, the companies that make commercial use of bamboo culms produce different kinds of solid waste rich in lignocellulosic biomass, which in some cases is not used and is discarded in landfills or incinerated in the open air; losing the possibility of recovering them and using them in other productive sectors. The research objective were to produce a biochar from Guadua agustifolia Kunth sawdust, evaluate its potential environmental and agricultural use, obtain a biochar/TiO2 composite to inactivate Escherichia coli and use the biochar as a soil conditioner in medicinal plants producing phenolic compounds and flavonoids. Biochar composite (produced at 300 °C for 1 h) involved TiO2 at 450 °C for 1 h for inactivation of E. coli (initial concentration: 6.5 ± 0.3 Log10 CFU mL− 1). For agriculture, 2% biochar was used to evaluate B. pilosa L. and G. angustifolia plant growth for 90 days. The biochar/TiO2 composite had a high photocatalytic activity on E. coli, generating a final count of 1.97 ± 0.2 Log10 CFU mL− 1 after 60 min. Biochar (2%) increased the total phenol and flavonoid content in the medicinal plant B. pilosa L. and total phenols in G. angustifolia, tested at the nursery stage. This study provides new information on the conversion and use of G. angustifolia sawdust as an alternative for new bio-based materials with environmental and agricultural applications. In addition, obtaining biochar and composite could positively impact the bamboo production chain in Colombia because of renewable and globally accepted alternatives that help capture gaseous emissions causing the greenhouse effect. [ABSTRACT FROM AUTHOR]

Nitrogen oxides (NOx) have numerous negative effects on both the environment and human health. They are major contributors to photochemical smog and acid rain. As a result, researchers are increasingly focused on developing de-NOx technologies. One effective method for removing NOx from the environment is selective catalytic reduction (SCR), with ammonia serving as the reductant (NH3–SCR). Rare earth-based catalysts have emerged as viable options for low-temperature NH3–SCR. Currently Ce-based NH3–SCR catalysts, such as CeO2–TiO2, CeO2–WO3, CeO2–MoO3, Ce–Mn–TiO2, CeO2–MnO2, Ce0.67Zr0.33O2, and CeO2–Fe2O3 have focused significant attention from researchers. The 4f orbitals of rare earth elements (REEs) are devoid of full electron occupancy. This attribute contributes to their distinct catalytic efficacy when employed as catalyst substrates. The oxygen storage capacity of Ce-based catalysts has further enhanced their popularity. Various methods, including microwave, hydrothermal, precipitation and sol–gel techniques, have been used by researchers to prepare catalysts in order to reduce the NOx emission. The paper has covered the impact of the preparation technique on rare earth catalyst performance and the NH3–SCR reaction mechanism to achieve a wide operating temperature. The global production and reserves of rare earth elements (REEs) worldwide have been thoroughly examined, and catalysts for the reduction of NOx emissions in automobiles by Ce and La have been explored. [ABSTRACT FROM AUTHOR]