Vol. 12, No. 3 (2024): Regular Issue

The main goal of the current research was to investigate the effect of particle and vegetation roughness arrangement on changes in the drag force in an open channel in different configurations, flow rates, and water depths. Therefore, a series of experiments were conducted in a flume with a length of 3.8 meters, a width of 0.8 meters, and a height of 0.55 meters located in the hydraulic laboratory of the Shahid Chamran University of Ahvaz. Drag forces were obtained for each test. The results of the tests showed the increase in the flow rate in most of the tests directly affected the amount of drag force. On average, at 15 L/s discharge, with an increase in depth from 10 to 20 cm, the momentum absorption can reach 60% for the particles' roughness. While the same conditions have occurred for vegetation roughness, the momentum absorption is less than 30%. The results provided effective results to know the performance of different arrangements in the scope of this research.

The objective of this paper is to investigate the dynamical behavior of a prey-predator system in which disease infection is in both the prey and predator populations. Prey and Predators are divided into two categories - the susceptible and the infected. The Lotka-Volterra predator-prey system's stability is investigated using the Takagi-Sugeno (T-S) impulsive control model and the Fuzzy impulsive control model. A system of four differential equations has been proposed and analyzed. The Takagi-Sugeno (T-S) impulsive control model and the fuzzy impulsive control model are used to explore the stability of the Lotka-Volterra predator-prey system. Numerical simulation provides the global stabilities and the fuzzy solution.

Nitrogen enrichment is a major problem for lakes and reservoirs, which may result in increased algae growth. Environmental factors, such as hydrodynamic disturbance, play an important role in the release of secondary pollution from sediments, especially in shallow lakes. In this study, the dynamic release of total nitrogen (TN) from sediments under different hydrodynamic conditions was investigated by conducting seven sets of laboratory experiments with a specialized apparatus. The TN, nitrate-nitrogen (NO_3-N) concentration in the overlying water and TN concentration in the sediment were measured simultaneously. Experimental results showed that the sediment nitrogen release was strongly affected by the hydrodynamic conditions, and the TN release amount increased greatly with enhanced hydraulic disturbance. Different with that under a constant shearing velocity, the release rate of TN was significantly influenced by the time-varying disturbance intensity, and the initial release process is crucial to the entire release. The massive resuspension of sediment arosed by strong hydrodynamic disturbance contributes to the high TN concentration in the water body, and the numerically calculated concentration of the suspended sediment has the same varying trend with the variation of TN concentration before reaching the equilibrium state. This relationship might be utilized to predict the release of TN under strong disturbance.

The current threats and deterioration of the coastal marine ecosystem require the scientific dissemination of their natural values in order to achieve immediate action by policy makers. The western marine areas of the Mediterranean present habitats that are unknown to most stakeholders, and their contribution to the well-being is difficult to identify. Thus, we have proposed an estimation of the economic value of the Ecosystem Services (ESs) in the marine coastal strip of Xàbia, north of Alicante, Spain. We conducted 14 face-to-face structured interviews with local experts with backgrounds in marine areas. We used the Analytic Network Process (ANP) to identify essential ESs in the mapped area. Participants identified as relevant a set of seven ESs (seafood, habitat services, climate regulation, waste treatment, biological control, recreation, and knowledge development). Using the Discounted Cash Flow method, we obtained the monetary value of each ESs. Our results reveal that one-third of the total value of the ecosystem corresponds to habitat services (e.g., life cycle maintenance, gene pool protection), whose major contribution is supporting waste treatment and biological control functions of the ecosystem. Our findings will provide useful information for marine management decisions and could enhance territorial conservation policies.

Wetland modeling under land use change (LUC) plays an important role in the maintenance of these valuable ecosystems. Here, the LUC effect on hydrological changes in Ajigol, Almagol and Alago international wetlands in northern Iran, was investigated using Long-term hydrological impact assessment (L-THIA) model and satellite images (Landsat 5, 7 and 8) during 1987-2018. Correlation test was also performed between LUC parameter and water quality changes during 2003-2018. The results showed that LUCs have directly affected the wetland hydrology in which a correlation coefficient (R-squared) of 0.70, 0.64 and 0.60 was observed between modeled and actual water volume in Almago, Ajigol and Alagol wetlands, respectively. In terms of water quality changes, agricultural land, distance from agricultural lands and urban land changes were closely related to the phosphate, nitrate, acidity, pH and turbidity changes of wetland water over time ($P<0.05$).

This study utilizes second-generation panel techniques to define the determinants of emissions in the G7 region during the 1990-2018 period. The outcomes of the Pesaran and Yamagata and Pesaran CD techniques show that there is a correlation between the cross-sectional units and there is slope heterogeneity among states. This study employed static and dynamic techniques including the Mean Group (MG), Augmented Mean Group (AMG), and CS-ARDL approaches. In the long term, sustainable energy and environmental innovations reduce emissions, while it is augmented by economic expansion and military expenses. The outcomes of the Granger causality test indicated that military expenses cause economic expansion and economic expansion causes emissions. Moreover, sustainable energy and energy innovations affect emissions. Therefore, it is suggested that policymakers should implement eco-friendly strategies such as the distribution of eco-innovation and sustainable energy to promote sustainable development and protect the environment.

This research addresses an important aspect of the Marine Strategy Framework Directive (MSFD, 2008/56/EC): the analysis of the socio-economic activities that use the marine environment in Italy. To this end, the study focuses on activities related to coastal municipalities as a total contribution of specific economic sectors linked to the sea. A rigorous accounting procedure, in line with the guidelines released by the European Commission's ESA (Economic and Social Assessment) 2010 Guidance, is provided in order to carry out a meticulous search (data mining) of all the budget items attributable to a reference list of activities and then to follow up with an accounting reclassification capable of describing the largest aggregate of the Sea Economy. The research examines data referred to two different years (2015 and 2019) for three fundamental socio-economic variables: employment, added value and production value. The comparative analysis over time and the spatial distribution dimension enables an in-depth examination of evolving trends and challenges for Italy's marine environment. A further analysis is performed also to detect the presence of a decoupling effect (when observable) between the socio-economic variables and the trend of some descriptors of the environmental quality. Hence, this research represents not just a significant step towards a complete fulfilling of the MSFD's requirements, but it also provides valuable insights for future informed policy interventions as well as for the development of sustainable management strategies.