Search

Copyright of Corrosion & Protection in Petrochemical Industry is the property of Corrosion & Protection in Petrochemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bengkulu City is situated within a subduction zone where the Indo-Australian and Eurasian tectonic plates converge, rendering the area highly susceptible to seismic activity. This study employs the microseismic method to assess seismic vulnerability and the subsurface rock structure at the Dendam Tak Sudah Lake Flyover Construction Site in Bengkulu City, which encompasses a swampy region. The microseismic method used was an inversion of the horizontal to vertical (H/V) spectral ratio (HV-Inv) for determining the dominant frequency (f0), amplification factor (A0), seismic sensitivity index (Kg), and shear wave velocity (Vs). The findings reveal that f0 in the study area range from 2.16 to 7.53 Hz, A0 vary from 0.40 to 3.79, and Kg values span from 0.03 to 6.04. The sedimentary layers exhibit an average thickness of 5-10 meters, with some locations showing significantly thicker sedimentary deposits. Notably, the highest seismic susceptibility is recorded at point T8. The Vs values range from 185.19 to 539.49 m/s, which are inversely proportional to the Kg values and indicate soil classifications varying from soft to medium. The overall seismic risk in the study area is moderate. These results offer key insights into geophysical and geological conditions in Bengkulu City, crucial for earthquake mitigation.

It is established that the fractions of the characteristic intensities of OH group vibrations attributed to intramolecular H-bonds of O3–H···O5 and O2–H···O6 types and intermolecular H-bonds of O6–H···O3 type of air-dried samples are 0.12, 0.1, and 0.2 for UAM-100 membrane and 0.12, 0.1, and 0.19 for UAM-50 membrane. It is shown that the characteristic intensity of the ν(OH) absorption band grows from 9.55 to 10.3 in a working sample of the UAM-100 membrane and a drop in the symmetry index to 0.75 was explained by the oxidation of aldehyde groups at C1 pyranose ring to the carboxyl (–COOH). It is proved that the fractions of intermolecular bonds of О6–Н···О3 and intramolecular H-bonds of O3–H···O5 and O2–H···O6 are 0.15, 0.09, and 0.13 that indicates not only the structural rearrangement of the hydrogen bond system but also possibly the formation of weak hydrogen bonds between hydroxyl groups of pyranose rings and molecules of the sedimentary layer. [ABSTRACT FROM AUTHOR]

The equations of wave motion are considered in this article for three-layered medium which consists of liquid and porous layers with finite depth and solid half-space such as ocean bed. By virtue of scalar potential functions for each layer, complicated differential equations of layers are reduced to ordinary differential equations. An analytical method is applied to determine the Green's functions of media based on an arbitrary shaped time-harmonic excitation at the interface of liquid and porous layers. A Mathcad code is provided to compute the complex integrals. Displacement and stress fields of three layers are discussed. Comparing with special cases, existing answers represent the validity of the proposed method. Numerical results are carried out for circular patch, ring and point loads, and the effects of various parameters on the behavior of the system are plotted. Finally, the achieved results were under discussion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nitrate-driven AOM process could potentially reduce 5.7–9.5% of methane emissions. • Nitrate-driven AOM activity was higher in low-latitude than high-latitude wetlands. • Nitrate-driven AOM activity and ANME-2d abundance were higher at 0–10 cm layer. • ANME-2d abundance and diversity varied under different plant species cover. • Nitrate-driven AOM process was affected by temperature, pH, NO 3 – and organic carbon. Coastal wetlands are an important methane emission source. Nitrate-driven anaerobic oxidation of methane (AOM), catalyzing via a novel clade of anaerobic methanotrophic archaea (ANME-2d), is a potentially important process for methane emission mitigation in coastal wetlands. However, the influence of regional and local environmental conditions, as well as plant species cover on this AOM process, remains unclear. Here, we investigated the horizontal and vertical distribution of nitrate-driven AOM activity and ANME-2d archaeal community in four coastal wetlands under both native and invasive plant species across southeast China. It was estimated that this AOM process could potentially reduce 5.7–9.5% methane emissions from the studied wetlands. Generalized linear mixed-effects model showed that sampling locations and sediment layers had greater impact on nitrate-driven AOM activity than plant species cover, and all these factors significantly affected the abundance of ANME-2d archaea. Nitrate-driven AOM activity was higher in low-latitude coastal wetlands than in high-latitude areas, and the activity positively correlated with mean annual temperature. Furthermore, both nitrate-driven AOM activity and ANME-2d archaeal abundance showed significant vertical variations along sediment profiles, with higher values in the slightly alkaline surface sediment. The plant species cover was found to impact the ANME-2d archaeal abundance and diversity by regulating the availability of substrates for the archaea. Overall, our study provides valuable insights into effects of regional and local environmental parameters and plant species cover on the horizontal and vertical distribution of nitrate-driven AOM activity and ANME-2d archaeal community in coastal wetlands. [ABSTRACT FROM AUTHOR]

Surface-flow constructed wetlands (CWs) are systems that replicate the nutrient reduction processes of natural wetlands and are considered suitable measures to reduce the nutrient losses from agricultural drainage discharge to surface waters. The present study aimed to investigate the biogeochemical stability of phosphorus (P) in three CWs. Intact soil cores were collected from each CW zone and included the soil and the sediment layer (average 28 mm thickness) formed by deposition of the incoming sediments with the water flow. Soil and sediment layer were analysed geochemically, including bulk density, pH, and total contents of carbon, nitrogen, P as well as different extracts of iron (Fe), aluminium and P. In situ measurements of soil redox potential, dissolved oxygen concentration and temperature were carried out in the CWs during 16 months. Grab water samples were collected across the CWs for determination of P species, total Fe, sulphate and pH. Soil core analysis revealed that the major P storage in the CWs was attributed to retention of Fe-bound P in the sediment layer. The Fe and total P (TP) retention differed significantly between CWs (11–63 g Fe m −2  yr −1 and 1–9 g TP m −2  yr −1 ). Amorphous Fe oxides constituted the major P sorbent fraction in the soil and sediments of all CWs, and the higher P sorption capacity in the sediment layer demonstrated the continuous supply of P sorbents to this layer. The stability of Fe-bound P in the anaerobic sediments seemed to be controlled by the high molar ratios of bicarbonate-dithionite extractable Fe (Fe BD ) to associated P, which varied from 21 to 49, and the presence of an aerobic sediment-water interface. [ABSTRACT FROM AUTHOR]

Wave propagation in a near-bottom layer containing gas bubbles is analyzed. Evolution equations are derived for intense acoustic waves and wave beams in a medium with an inhomogeneous bubble distribution. The field of an intense beam along the axis of the focusing sound channel is calculated. The coefficients of reflection and passage of sound from a homogeneous medium into a bubble layer and back again are calculated. It is shown that the near-bottom layer can effectively trap rays incident on it and ensure a waveguide propagation character. The presence of bubbles increases both the interval of angles at which the wave penetrates the layer and the interval of angles at which rays undergo total internal reflection and do not depart the layer. The acoustic field in the layer from a point source is calculated. [ABSTRACT FROM AUTHOR]

The theoretical studies of reducing the productivity of ultrafiltration (UF) modules, due to the formation of a highly concentrated sediment layer on the membrane surface, are given in the paper. The main purpose of the research is to justify the advantage of the tangential filtration over a dead-end when operating the UF module on an industrial scale. The UF module modes are considered and their comparison is given in the paper. An algorithm that allows demonstrating the magnitude of the possible sediment layer formation on the membrane surface in the UF module at the dead-end and tangential module operation, and its impact on reducing the module productivity, is developed and presented. The obtained results can be of practical use to compile operation modes of ultrafiltration systems. This research may be useful for design engineers, as well as for scientists, involved in research in the field of water purification by the UF method. [ABSTRACT FROM AUTHOR]