International Journal of Coastal, Offshore and Environmental Engineering
Volume:8 Issue: 4, Autumn 2023

Quay walls are sheltering structures used for protecting coastal regions against wave-induced forces. Because of the random nature of the wave behavior, the application of physical models for the study of wave-structure interaction can be quite efficient. The aim of this study was to investigate the behavior of quay walls under random waves through experimental methods. The study used walls with vertical geometrical form, which were exposed to sea random waves under the JONSWAP spectrum. Surface level and wall strain values were measured using built-in sensors. A neural network model was developed using the feed-forward method with the backpropagation algorithm to analyze the time series of water surface level and strain. High coefficients of determination during the training and verification phases were observed, indicating good network performance. Self-correlation analysis of the time series showed that the data exhibited first-degree Markov characteristics. This finding was taken into consideration and increased the coefficients of determination in the neural network model.

Given the necessity of knowing the risk of future tsunamis in actions related to tsunami hazard mitigation, the Probabilistic Tsunami Hazard analysis (PTHA) approach has been accepted as the basis for tsunami risk assessment studies for high-risk areas such as the Makran region. Considering the uncertainties associated with fault parameters and the random nature of earthquake in PTHA, simulation a large number of potential tsunami scenarios is required in future tsunami studies of the Makran Subduction Zone (MSZ). To optimize the number of scenarios in these studies, appropriate values for the ranges and change intervals of some uncertain seismic parameters in different scenarios are determined in the present study. For this, the values used in previous studies for earthquake magnitude and depth as well as dip and rake angles of MSZ's tsunamigenic earthquakes are investigated; and the effects of variations in these parameters on the tsunami waves are evaluated through numerical modeling and sensitivity analysis. The results show a minimum value of Mw0.1 for the interval of earthquake magnitude variations must set in developing potential tsunami scenarios. Also, considering two or three values in the range of 2º to 20º and 10km to 30km, respectively, as probable values for the dip angle of the MSZ and the depth of tsunamigenic earthquakes seems sufficient. However, if the minimum number of scenarios is desired, selecting a unit value for the dip angle in the range of 10º to 15º and a constant earthquake depth of 10km can be acceptable.

Implementing carbon capture and storage (CCS) technologies is essential to mitigate the damaging effects of climate change due to the earth’s temperature increase. However, despite the potential benefits of CCS, its acceptance has been slow. This paper identifies and examines the barriers to CCS acceptance, which include technical, economic, regulatory, and social factors. Economic barriers include the lack of financial incentives while regulatory barriers include the absence of a comprehensive legal framework. Lastly, social barriers include the lack of public awareness and understanding of CCS and the negative perception of technology. Technical barriers include a deficiency of desired infrastructure in all stages of CCS including capture, transportation, and storage. Firstly, there is a deficiency in the development of efficient carbon capture technologies. Secondly, the transportation of captured carbon dioxide poses challenges to move the captured CO2 to suitable storage sites. Lastly, the storage of carbon dioxide in suitable geological formations requires the identification and characterization of suitable sites, while ensuring the long-term safety of the stored CO2.

Coastal protection engineering works may result in changes in characterization of the hydrodynamics and bottom topography of the near shore domain. Since measuring the changes in underlying bathymetric is very costly, developing equilibrium beach profiles which can demonstrate the important features of the bottom topography is of importance. In order to assess the bottom topography of the Caspian Sea in vicinity of Astara Port, some field measurements of beach profiles were carried out. The purpose of this paper is to investigate the influences of the breakwaters on beach morphological evolution in the vicinity of them to identify how the extension of breakwaters altered the sea bed topography. To describe evolving cross-shore profiles in the study area, beach profile surveys were conducted by a single-beam echo sounder. Results showed that the breakwaters considerably affected their surroundings. Furthermore, comparisons of measured beach profiles with Dean's profile model for the equilibrium beach profile illustrated that: while the Dean's profile can precisely represent the time-mean profiles in the coastal area, it must be used with care in the structure vicinity. As a result, the coefficient, A, in Dean's equilibrium equation in the front of the breakwater will be about two or three times more than as when it used for the coast without the structure. It is because of the presence of coarser grains in front of the breakwater. It is while the power term in Dean's equation is the same for both the cases without and with the structure which is 2/3.

This study concentrates on the 61tidal constituents of 17stations on the north of Oman Gulf(OG),Strait of Hormuz(SH)and Persian Gulf(PG).Five-years tidal data(2014-2018,30-minutes intervals) was achieved by Iran National Cartographic Center to calculate mean levels of stations.Then,t_tide library was used to calculate 61 tidal constituents by 95%of confidence in Matlab for 2018 data.Then, they sorted by the magnitude of the amplitude to express the most significant ones in each stations. Results shows that the mean levels of the northwest and northeast of PG are mirror images.Although the major diurnal and semidiurnal tidal constituents of 11stations areM2,K1,S2andO1,by changes in order of importance; in 6stations,N2 constituent is more important than O1. These exceptions go back to the stations of SH and northwest ofPG, which shows the importance of the SH bending and the shallowing of the northwest of PG. Moreover, the top ten components of all stations are not 10 unique components and they include 21 components.Due to the Form factor,F,all the studied stations are mainly mixed semidiurnal type. The predicted t-tide tides show small errors compare with the original ones. The results also showed that the range and components of harmonic astronomical tides are influenced by local geography. On the head of PG,the EmamKhomeini’s tides is sharp due to the shallow water, and the semidiurnal components(S2andN2)are much stronger than the diurnal components(O1andP1).The Pol Port’s tides is effected by narrowing of SH.Therefore, in some ports, non-tidal parameters such as geographical shape or shallow water are effective while considering astronomical components of moon and sun.

The major challenge in marine environment imaging lies in addressing the haziness induced by natural phenomena, such as absorption and scattering in underwater scenes. This haze significantly impacts the visual quality of underwater images, necessitating improvement. This paper presents a novel approach aimed at enhancing the efficiency of Gaussian filters for reducing Gaussian noise in underwater images. The method introduces a pipeline structure in the Gaussian filter implementation and evaluates the influence of employing approximate adders on overall performance. Simulation results reveal a notable speed enhancement exceeding 150%, coupled with a substantial reduction in power consumption exceeding 34%. However, these advantages are tempered by an increase in spatial requirements. The study recognizes the inherent tradeoff between output quality and power, highlighting the applicability of the proposed design in error-resilient applications, particularly in image and video processing domains. In essence, the presented approach offers a compelling solution where the benefits of accelerated speed and reduced power consumption outweigh spatial constraints, contributing to the advancement of underwater image enhancement techniques.