Sea surface features and internal waves in the sea

On several oceanographic cruises conducted by Andhra University, an unusual sea-surface phenomenon was observed which consisted of long streaks of alternately smooth and rough water. On one occasion at the northern end of "Swatch of No Ground", temperature structure was measured at the same time as a passing of such series of wide sea surface streaks.

Morphological: Optical, and Mechanical Characterizations of Non-Activated and Activated Nanocomposites of SG and MWCNTs

Nanocomposites of silica gel (SG) and multiwalled carbon nanotubes (MWCNTs) of relatively low concentrations (0.25, 0.50, and 0.75 wt%) were characterized before and after annealing. Adsorption is a surface phenomenon, and based on this, the morphology of the composites was investigated by scanning electron microscopy (SEM). The produced images show that the MWCNTs were embedded into the silica gel base material. Fourier transform infrared (FTIR) transmittance spectroscopy showed that MWCNTs were not functionalized within the matrix of silica gel and MWCNT composites. However, after annealing the composites at 400 °C for 4 h in air, evidence of activation was observed in the FTIR spectrum. The effects of the embedding of MWCNTs on porosity, specific surface area, and pore size distribution were studied using Raman spectroscopy. The Raman spectra of the prepared composites were mainly dominated by characteristic sharp scattering peaks of the silica gel at 480, 780, and 990 cm−1 and a broad band centered at 2100 cm−1. The scattering peaks of MWCNTs were not well pronounced, as the homogeneity of the composite is always questionable. Nanosizer analysis showed that at 0.25 wt%, the distribution of MWCNTs within the silica gel was optimal. Vickers hardness measurements showed that the hardness increased with the increasing weight percent of MWCNTs within the composite matrix, while annealing enhanced the mechanical properties of the composites. Further studies are required to investigate the pore structure of silica gel within the matrix of MWCNTs to be deployed for efficient cooling and water purification applications.

Clay Minerals Effects for Metal Reclamation from Leached Solution

The recent advancements in technology play a pivotal role in mankind’s life and have a significant stint in the generation of E-waste. The present investigation focuses on the recovery of heavy metals from Printed Circuit boards (PCBs) by applying two efficient techniques viz., leaching and adsorption. A combination of leaching and adsorption is a novel and productive approach to recovering heavy metals from like PCBs. After the phases of chemical leaching, the solution was recovered through adsorption and is eco-friendly. The process is carried out to increase the separation rate, reduce the time spent and reach the limits of incineration and pyrolysis methods. Adsorption provides the recovery of heavy metals with respect to the required adsorbent since it is a surface phenomenon. The optimum condition of process variables was found through response surface methodology (RSM). The maximum recovery of copper ions (97.33%) was obtained at the optimum operating conditions such as adsorbent size of 0.04 mm, adsorbent dosage of 3.5 gm L−1 and the temperature of 80°C with 0.845 desirability. This investigation was found to be an eco-friendly way to recover copper ions and does not cause any environmental issues.

Materials for methylene blue adsorption

Adsorption is a surface phenomenon, in which the adsorbate is adhered to an adsorbent material and have been study for the removal of textile dyes, which have high toxicity to the aquatic environment. One of the dyes that stands out is methylene blue, which is organic, basic, aromatic, heterocyclic and molecular formula (C16H18ClN3S). In this study, we aim was to carry out a bibliography review in national and international scientific journals with articles published in the period from 2005 to 2019, of the adsorbent materials for the adsorption of the methylene blue dye. The materials reported are: mango seed powder, wheat husks, activated carbon obtained from rattan sawdust, activated carbon prepared from coconut shell, garlic shell, NaOH modified pummell shell, activated carbon (coconut shell and modified with NaOH), activated carbon (pea peel), HCl modified watermelon peel, potato peel, ZnCl2 activated cashew nut peel, mesoporous carbon obtained from fish scales, pineapple peel and bamboo. Our review indicate that the adsorbent materials found in the literature for methylene blue adsorption have high adsorption capacities. The adsorption capacities are high and depend on several parameters, which influence the adsorption (pH of the medium, mass and particle size of the adsorbent material, concentration of adsorbate (methylene blue), temperature and time of contact of the adsorbate with the adsorbent.

Enhancing Weathering Resistance of Wood—A Review

Wood is a truly sustainable and aesthetically pleasant material used in indoor and outdoor applications. Every material, including wood, is expected to have long-term durability and to retain its original appearance over time. One of the major disadvantages of wood is the deterioration of its surface when exposed outdoors, known as weathering. Although weathering is primarily a surface phenomenon, it is an important issue for wood products as it affects their appearance, service life, and wood-coating performance. To encourage the use of wood as a material for joinery and other building components, the results of research into increasing the weathering resistance of wood are extremely significant. The development of weathering protection methods is of great importance to reduce the maintenance requirements for wood exposed outdoors and can have a major environmental impact. There are various methods of protecting wood surfaces against weathering. This paper provides a literature survey on the recent research results in protecting wood from weathering. The topics covered include surface treatments of wood with photostabilizers; protection with coatings; the deposition of thin film onto wood surfaces; treatments of wood with inorganic metal compounds and bio-based water repellents; the chemical modification of wood; the modification of wood and wood surfaces with thermosetting resins, furfuryl alcohol, and DMDHEU; and the thermal modification of wood.

Nature and significance of rift-related, near-surface fissure-fill networks in fractured carbonates below regional unconformities

Fissure-fill networks are a widely recognized, but relatively little described, near-surface phenomenon (<1–2 km) hosted in carbonate and crystalline basement rocks below regional unconformities. Faults and fractures in otherwise tight Devonian carbonate basement rocks of the Tor Bay region, Devon, SW England are associated with the development of millimetre- to decametre-wide fissures containing red-coloured early Permian sedimentary material, vuggy calcite mineralization and wall rock collapse breccia. These features preserve evidence about the style and history of fault deformation and reactivation in near-surface settings and on fluid-related processes, such as elutriation and/or mineralization. Field observations, palaeostress analysis and fracture topology analyses show that the rift-related faults and fractures created a network of long-lived open cavities during the development of the Portland–Wight Basin in the early Permian. Once formed, they were subjected to episodic, probably seismically induced, fluid fluxing events and local karstification. The large, well-connected networks of naturally propped fractures were (and possibly still are) important fluid migration pathways within otherwise low-permeability host rocks. These structures are probably equivalent to those observed in many other rift-related, near-surface tectonic settings and suggest that the Tor Bay outcrops can be used as a global analogue for sub-unconformity open fissure systems hosted in low-permeability basement rocks.Supplementary material: Appendix A is available at https://doi.org/10.6084/m9.figshare.c.5023103

Trends and variations in heat uptake of the Arctic climate system

&lt;p&gt;A recent assessment of the coupled atmosphere-ocean-sea-ice energy budget of the Arctic using largely independent observational data sources demonstrated a high level of consistency of yearly means and annual cycles of lateral and vertical energy fluxes and storage terms. Moreover, contemporary Arctic regional energy imbalance has been found to be of similar magnitude (~1Wm&lt;sup&gt;-2&lt;/sup&gt;) as Earth&amp;#8217;s global energy imbalance. This suggests that Arctic amplification is predominantly a surface phenomenon and its imprint on the vertically integrated energy budget is small. Nevertheless, the annual cycle of the observed Arctic energy budget has amplified over the past two decades, with marked changes in seasonal patterns of energy fluxes and storage. This contribution draws on satellite observations, mooring-derived oceanic fluxes, data from the fifth European Re-Analysis (ERA5), and state-of-the-art ocean reanalyses to examine recent changes in Arctic heat accumulation as well as trends and variability in seasonal energy budgets. Implications for seasonal energy transports from mid-latitudes towards the Arctic will be discussed as well.&lt;/p&gt;

Global reduction of in situ CO 2 transfer velocity by natural surfactants in the sea-surface microlayer

For decades, the effect of surfactants in the sea-surface microlayer (SML) on gas transfer velocity ( k ) has been recognized; however, it has not been quantified under natural conditions due to missing coherent data on in situ k of carbon dioxide (CO 2 ) and characterization of the SML. Moreover, a sea-surface phenomenon of wave-dampening, known as slicks, has been observed frequently in the ocean and potentially reduces the transfer of climate-relevant gases between the ocean and atmosphere. Therefore, this study aims to quantify the effect of natural surfactant and slicks on the in situ k of CO 2 . A catamaran, Sea Surface Scanner (S 3 ), was deployed to sample the SML and corresponding underlying water, and a drifting buoy with a floating chamber was deployed to measure the in situ k of CO 2 . We found a significant 23% reduction of k above surfactant concentrations of 200 µg Teq l −1 , which were common in the SML except for the Western Pacific. We conclude that an error of approximately 20% in CO 2 fluxes for the Western Pacific is induced by applying wind-based parametrization not developed in low surfactant regimes. Furthermore, we observed an additional 62% reduction in natural slicks, reducing global CO 2 fluxes by 19% considering known frequency of slick coverage. From our observation, we identified surfactant concentrations with two different end-members which lead to an error in global CO 2 flux estimation if ignored.