Applied Sciences

This paper addresses the seismic retrofitting of masonry churches with timber roofs by designing a ductile roof diaphragm with a new energy-based methodology. The proposed approach relies on nonlinear dynamic analyses conducted on an equivalent structural model. In this model, masonry nonlinearity is represented by rotational plastic hinges at the base of the equivalent wall elements. Roof system nonlinearity is modeled by shear plastic hinges simulating the energy dissipation of steel connections. In the equivalent model, the earthquake is implemented using a set of spectrum-compatible accelerograms. The dynamic response of the aforementioned plastic hinges is analyzed in terms of equivalent damping during the seismic events by extracting the relevant hysteresis cycles. This allows for the evaluation of both dissipated and strain energy. The estimation of the equivalent damping ratio provided by the roof diaphragm is based on multiple design configurations. After identifying the maximum achievable damping ratio, the study suggests ways to determine the corresponding roof stiffness, which defines the optimal retrofit configuration. This configuration is then implemented in a three-dimensional model that includes nonlinear properties for both masonry and connection elements, allowing a validation of the seismic response obtained from the initial equivalent model with a more complex and detailed model. Finally, a seismic response comparison is conducted between the optimized dissipated energy configuration, based on damping ratio evaluation, and an overstrength design variant determined considering the elastic behavior of the roof connections.

This paper focuses on handling traffic demands dynamically in a multi-layer IP-over-elastic optical network (IP-over-EON). We propose a mechanism that uses two types of optical resources. Some resources are visible for the network layer to serve IP traffic. Another part is hidden and reserved for handling congestions solely in the optical layer when resources in the network layer are insufficient. In such a case, the proposed algorithm tries to establish a new lightpath, allocating hidden optical resources. Extensive discrete-event computer simulations were conducted under various network conditions to evaluate the performance of the proposed solution, using two network topologies, the NSF15 and UBN24 networks. The results obtained confirm that the new solution allows for a significant decrease in the bandwidth blocking probability with better utilization of resources compared to the reference scenario (only IP).

Cadmium (Cd) contamination in agricultural soils poses a significant risk to crop production and food safety. This study explored the role and mechanisms of manganese (Mn) in mitigating Cd toxicity using two rice genotypes: ZS97B (Cd-tolerant) and MY46 (Cd-sensitive). A hydroponic experiment was conducted under two Mn levels (0 and 100 µM) and three Cd levels (0, 5, 10 µM). Exposure to 10 µM Cd significantly inhibited plant growth and induced physiological disorders, with more severe effects observed in MY46 than in ZS97B. The addition of Mn markedly alleviated Cd toxicity, as reflected by increased antioxidant enzyme activities and reduced malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) contents in both roots and shoots. Gene expression analysis showed that Mn addition up-regulated genes related to antioxidant enzymes and down-regulated key Cd uptake and transport genes, including OsNramp1, OsYSL2, OsMTP9, and OsHMA3. These changes contributed to enhanced antioxidant capacity and reduced Cd accumulation in rice plants under Cd stress. Our findings demonstrate that appropriate Mn application can effectively reduce Cd accumulation and alleviate toxicity in rice grown in Cd-contaminated environments.