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The purpose of this study is to use polybenzoxazine (Pbz) functionalized ZrO₂ nanoparticles to synthesize polyurethane (PU)-PbZ/ZrO₂ nanocomposite. The results derived from the electrochemical impedance spectroscopy (EIS) and polarization studies indicated the superior anticorrosive activity of PU-Pbz/ZrO₂ nanocomposite coatings compared to those of plain PU coatings. The decreased corrosion current was detected on the scratch of the PU-Pbz/ZrO₂ nanocomposite-coated mild steel surface by scanning electrochemical microscopy (SECM) compared to other studied coatings. The superior anticorrosive and mechanical properties of the proposed nanocomposite coatings provide a new horizon in the development of high-performance anticorrosive coatings for various industries.

The Pbz functionalized ZrO₂ nanoparticles were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) and thermogravimetric analysis (TGA) in terms of the structural, morphological and thermal properties of these coatings. A different formulation of coatings such as PU, PU-Pbz, PU-ZrO₂ and PU-Pbz/ZrO₂ were prepared and investigated for their corrosion protection performance on mild steel in natural seawater by electrochemical techniques. The surface morphological studies were done by SEM/EDX and XRD analysis.

The superior anticorrosive property of the proposed nanocomposite coatings provides a new horizon in the development of high-performance anticorrosive coatings for various industries. Addition of Pbz wrapped ZrO₂ nanoparticles into the PU coating resulted in the blockage of charge transfer at the metal/electrolyte interface, which reduced the dissolution of mild steel. It was revealed from the SEM/EDX analysis that the formation of the corrosion products at the metal/electrolyte interface behaved as the passive layer which reduced the dissolution of steel.

The inclusion of polybenzoxazine functionalized ZrO₂ nanoparticles to the polyurethane coating reinforces the barrier and mechanical properties of PU-Pbz/ZrO₂ nanocomposite, which is due to the synergistic effect of ZrO₂ and Pbz.

The purpose of the study is to present a frequency domain spectral finite element model (SFEM) based on fast Fourier transform (FFT) for wave propagation analysis of smart laminated composite beams with embedded delamination. For generating and sensing high-frequency elastic waves in composite beams, piezoelectric materials such as lead zirconate titanate (PZT) are used because they can act as both actuators and sensors. The present model is used to investigate the effects of parametric variation of delamination configuration on the propagation of fundamental anti-symmetric wave mode in piezoelectric composite beams.

The spectral element is derived from the exact solution of the governing equation of motion in frequency domain, obtained through fast Fourier transformation of the time domain equation. The beam is divided into two sublaminates (delamination region) and two base laminates (integral regions). The delamination region is modeled by assuming constant and continuous cross-sectional rotation at the interfaces between the base laminate and sublaminates. The governing differential equation of motion for delaminated composite beam with piezoelectric lamina is obtained using Hamilton’s principle by introducing an electrical potential function.

A detailed study of the wave response at the sensor shows that the A0 mode can be used for delamination detection in a wide region and is more suitable for detecting small delamination. It is observed that the amplitude and time of arrival of the reflected A0 wave from a delamination are strongly dependent on the size, position of the delamination and the stacking sequence. The degraded material properties because of the loss of stiffness and density in damaged area differently alter the S0 and A0 wave response and the group speed. The present method provides a potential technique for researchers to accurately model delaminations in piezoelectric composite beam structures. The delamination position can be identified if the time of flight of a reflected wave from delamination and the wave propagation speed of A0 (or S0) mode is known.

Spectral finite element modeling of delaminated composite beams with piezoelectric layers has not been reported in the literature yet. The spectral element developed is validated by comparing the present results with those available in the literature. The spectral element developed is then used to investigate the wave propagation characteristics and interaction with delamination in the piezoelectric composite beam.

This paper aims to conduct a comprehensive literature review in the tidal energy physics, the ocean environment, hydrodynamics of horizontal axis tidal turbines and bio-mimicry.

The paper provides an insight of the tidal turbine blade design and need for renewable energy sources to generate electricity through clean energy sources and less CO₂ emission. The ocean environment, along with hydrodynamic design principles of a horizontal axis tidal turbine blade, is described, including theoretical maximum efficiency, blade element momentum theory and non-dimensional forces acting on tidal turbine blades.

This review gives an overview of fish locomotion identifying the attributes of the swimming like lift-based thrust propulsion, the locomotion driving factors: dorsal fins, caudal fins in propulsion, which enable the fish to be efficient even at low tidal velocities.

Finally, after understanding the phenomenon of caudal fin propulsion and its relationship with tidal turbine blade hydrodynamics, this review focuses on the implications of bio-mimicking a curved caudal fin to design an efficient horizontal axis tidal turbine.

This paper analyzes two external costs often associated with port development, cost to fisheries from marine dredge disposal and damages from air pollution, using estimates of development and operation for a proposed (but since cancelled) container port as a case study. For dredge disposal, a bio-economic model was used to assess short- and long-term and indirect (joodweb) damages to fisheries from marine disposal of clean sediments. In the case of air pollution, estimates of annual activity levels and emission coefficients are used to estimate incremental annual emissions of three key pollutants (NOx, HC and CO) for trucks, trains, yard vehicles, and vessels. These estimates allow for phasing in of strict new air pollution regulations. For both external costs, sensitivity analyses are used to reflect uncertainty. Estimates of shadow values in year 2002 dollars amount from $0.094 per cubic yard to $0.169 per cubic yard of clean dredged material for the selected disposal site and from $0.0584 per mile (jor current control standards) to $ 0. 0023 per mile (after phasing in of new regulations) for air pollution from heavy trucks.

The losses in a fan unit consisting of rotor, guide vanes and tail fairing have been studied and the average losses are expressed in terms of non‐dimensional similarity parameters, frequently referred to as ‘fan laws’. It was found that for a specified duty and fan geometry the losses depend on: (a) The magnitude of the lift‐drag ratio of the rotor blades. (b) The drag coefficient of the guide vanes. (c) The loss over the tail faring. Since for complete similarity the parameters for model and prototype are considered to be equal, the discrepancy in losses between model and prototype, that is, scale effect, is mainly due to the variations of the aerodynamic characteristics of the blade and guide‐vane profile with the Reynolds number.

As a coastal emerging country, export-led marine economy has been the development model of Vietnam over the past decades since The Renovation 1986. Given the rise of globalization, regional economic integration and logistics enhancement have been identified as key engines for economic sustainability by Vietnamese government. Nevertheless, little sectoral and sub-sectoral evidence has been given for the platform shaped by policies relevant to export, logistics performance and regional economic integration. The paper employs the trade gravity model to study the relationship between seafood export, logistics performance and regional economic integration in the case of Vietnam. Sectoral and sub-sectoral trade gravity models are employed. Logistics performance from the exporter-side and importer-side is included in the estimations. Membership to effective regional trade agreements of Vietnam are proxies for regional economic integration. Zero trade issue is resolved by the Pooled Ordinary Least Squares (POLS), Poisson Pseudo-Maximum Likelihood (PPML) and Heckman Sample Selection estimations, while endogeneity is tackled by the difference and system Generalized Method of Moments (GMM) models. Findings vary by estimation methods, data levels, product groups, and whether which side is considered. In addition, theoretical contributions and some seafood export-driving policy recommendations relevant to regional economic integration and logistics performance development are discussed.

The Ba River catchment and delta on the island of Viti Levu, Fiji, supports a wealth of livelihoods and is populated by diverse communities who are living with an increased frequency and intensity of hydro-meteorological hazards (floods, cyclones and droughts). Participatory mapping as part of focus group discussions is a tool that can be used to elucidate communities’ understanding of the differing impacts of multiple hazards, as well as the strategies used to prepare and respond to different hazards. In this chapter, the authors present the results of qualitative research undertaken with members of three communities along the Ba River, from the Nausori highlands to the coastal mangroves, with a particular focus on recent floods (2009, 2012) and Tropical Cyclone Winston (2016). The communities draw on a wide range of livelihood strategies from fishing and agriculture to tourism and outside work. Natural hazard events vary in their impact on these livelihood strategies across the landscape and seascape, so that community members can adjust their activities accordingly. The temporal ‘signatures’ of ongoing impacts are also variable across communities and resources. The results suggest that taking a broad, landscape (and seascape) approach to understanding how communities draw livelihoods is valuable in informing effective and inclusive adaptation strategies for environmental change. Furthermore, documenting how the landscape is used in a mapped output may be a valuable tool for future social impact assessment for resource extraction activities.

Turbine blades in gas turbine engines operate at elevated temperatures and in highly oxidising atmospheres that can be contaminated with fuel residues and sea water salts. These components, which are expensive to produce, are subjected to high stresses during operation but must be totally reliable during their design life. An economic way to maintain blade properties is to coat the base metal superalloy with a protective layer capable of resisting both high temperature oxidation and hot corrosion. Conventional aluminide coatings are widely used for this purpose but platinum aluminides offer improved corrosion resistance. A collaborative exercise involving Rolls‐Royce and Johnson Matthey has now resulted in the development of a platinum aluminide diffusion coating that offers some advantages over the commercial systems.

Introduction The degree of adsorption of organic inhibitors on a metal surface in presence of halide anion is predominantly influenced by the synergistic effect. The synergistic effect brings about an improvement in inhibition as a result of chemisorption or physical adsorption depending on the nature of the interaction between the halide and the cation of the inhibitor. This effect is partly attributed to the stabilization of the adsorbed anion layer by an organic cation through a possible covalent linkage. The degree of availability of electrons influences the mode of adsorption. Investigations on ferric ion corrosion have shown that the synergistic inhibition effects the corrosion processes by primarily increasing the polarization of the cathodic reaction. The adsorption of quinoline on 18–8 steel in the presence of halider ions is predominantly influenced by the synergistic effect. It has been found that the addition of smaller concentration of quinoline inhibits the cathodic reaction and higher concentrations of quinoline inhibit the anodic reaction as well. According to Iofa the formation of an adsorbed layer of positively charged ion retards the transfer of cation through a binary layer and lowers the transfer rate. Work on amines has shown that tertiary and secondary amines are stronger than the primary amines as a result of increase of dipole moment of the doublet, increase of ionisation energy and increase of polarizability. Basicity and stearic effects, both are important. The high effectiveness of cyclic amines with more than seven carbon atoms appears to be correlated with the character of the free electron. It has been shown that whereas the organic compounds of cationic type were weakly absorbed on the iron surface in H2SO4 the addition of halides produced a considerable increase in the adsorption. Cavallaro and others have shown that several nitrogen molecules inhibit both the anodic and cathodic reactions.