The University of Guilan (Persian: دانشگاه گیلان, Danushgah-e Gilân) is an institute of higher education and graduate studies in Rasht, a large city in the province of Guilan, in Northern Iran, bordering the Caspian Sea.It has nearly 18,000 students enrolled.
The present work is concerned with the application of the variational differential quadrature (VDQ) method [Appl. Math. Model., vol. 49, pp. 705–738] to the optimal control problems. The basic idea is converting equations, performance index and boundary conditions to a functional using the Lagrange method which must be minimized or maximized. In the VDQ method, an efficient matrix formulation using accurate integral and differential operational matrices is developed for discretizing the obtained weak form equation. Finally, a system of algebraic equations is obtained that can be solved using iterative methods. Several types of multi-dimensional optimal control problems can be solved using this approach. To study the efficiency of the VDQ method, some test problems are solved, and the obtained results are compared with those of MATLAB optimization tools or exact methods. It is indicated that the proposed numerical method has the capability of solving optimal control problems accurately. Additionally, the formulation is presented in a manner that facilitates clearer understanding and easier implementation in MATLAB.
The search for sustainable ways to produce important petrochemicals like light olefins has been accelerated by the increasing CO2 levels in the atmosphere and the worsening effects of global warming. While the methanol-to-olefins (MTO) technique shows potential for reducing reliance on fossil fuel feedstocks, it remains extremely energy-intensive and requires significant environmental considerations. Concurrently, the proper disposal of hazardous refinery wastes-especially oil sludge-has become a major problem worldwide. A process-simulation framework for evaluating sustainable routes to find optimization possibilities and to evaluate the performance of waste-derived feedstocks in petrochemical uses was developed and tested using a fully integrated 4E (energy, exergy, economic, and environmental) framework. The Aspen HYSYS model allows a thorough investigation of system behavior under industrially pertinent settings by including all the main thermochemical conversion, methanol synthesis, and olefin manufacturing units. The findings indicate that methanol production is the main cause of exergy destruction (87%), followed by gasification (7%) and light olefin synthesis (4%). The largest cumulative thermodynamic losses come from heat exchangers, which account for 49% of all exergy destruction and 58% of all energy use because of non-ideal heat recovery setups. Exergoeconomic analyses show that compressors are the most expensive units (with an exergoeconomic factor of about 95%), but most heat exchangers show factors less than 15%, which means there is a lot of room for inexpensive improvements. The exergoenvironmental study reveals that during the gasification and compression phases, environmental effects rise dramatically as the cracked gas stream increases from 1,980 to 8230 Pts/h and then to 25,004 Pts/h following compression due to shaft power inputs and exergy destruction. The mixed syngas used to make methanol has the biggest environmental impact in the plant (52,805 Pts/h). In contrast, the environmental impact per exergy unit of the final light olefin products remains rather low (approximate to 12.9 Pts/GJ), and olefin synthesis reactors show great environmental efficiency (environmental factor > 90%). Because they show the highest environmental load, purification columns and a number of heat exchangers are top priorities for development.
This article explores how populist discourse reshapes urban planning conflicts and legitimizes speculative development in Hamadan, Iran. Using post-structuralist discourse theory and qualitative analysis of 1248 local media texts (2017–2024), it shows how signifiers like “the people” and “justice” construct antagonistic narratives that erode planning authority. The study introduces the concept of a “speculation network” involving political, commercial, and media actors that exploit participatory rhetoric for elite gain. It finds that populism marginalizes expertise and reinforces monopolies, with media as a key discursive arena. The article advances agonistic planning theory and advocates media-aware, conflict-sensitive planning approaches.
Abstract This study presents a comprehensive investigation into the concurrent thermal and radiation shielding performance of ground granulated blast furnace slag (GGBFS)-based geopolymer concrete (GPC) exposed to temperatures up to 600°C for durations of up to 120 min. Although GPC is widely acknowledged for its enhanced fire resistance and environmental benefits over ordinary portland cement (OPC) concrete, its dual functionality as a load-bearing and radiation-shielding material under thermal stress has not been rigorously quantified. This work bridges that gap by integrating mechanical, radiological, and microstructural analyses, directly linking thermally induced damage—such as dehydration, porosity growth, and microcracking—to measurable declines in performance. Experimental results (mean ± SD and n = 5 ) showed that after 120 min at 600°C, compressive strength decreased by 59.4%, from 36.47 ± 1.82 to 14.81 ± 0.74 MPa . Concurrently, the gamma ray linear attenuation coefficient and neutron removal cross section diminished by 36.5% and 25.3%, respectively, accompanied by marked increases in half-value and 10th-value layer thicknesses. A critical thermal threshold was identified near 400°C, beyond which degradation accelerates in a nonlinear manner. Statistical validation and machine learning models [artificial neural network (ANN), support vector machine (SVM), and long short-term memory (LSTM)] confirmed temperature and porosity as the dominant degradation drivers. Furthermore, mix design optimization via a genetic algorithm demonstrated that adjusting GGBFS content and Na 2 SiO 3 /NaOH ratios can recover up to ∼ 10 % of lost performance at 600°C. These findings challenge the assumption that GPC’s inherent fire resistance ensures reliable multifunctionality in nuclear applications, underscoring the necessity of thermally tailored geopolymer composites for extreme environments.
Geometrically nonlinear bending behavior of functionally graded porous nanocomposite circular plates reinforced with graphene nanoplatelets (GPLs) under asymmetric transverse loading is investigated in this study. To this end, an analytical solution framework is used to determine the nonlinear bending response of functionally graded GPL-reinforced porous circular plates. The theoretical model incorporates the first-order shear deformation plate theory (FSDPT) together with the von Karm an nonlinear strain-displacement relations. Five coupled nonlinear equilibrium equations are derived using the principle of minimum potential energy and are subsequently reduced to three governing equations through the introduction of a force function. These equations are solved using a combined perturbation-Fourier series technique. The results demonstrate that the porosity coefficient, porosity and GPL distribution patterns, and boundary conditions significantly influence the nonlinear bending response. In particular, increasing the porosity results in larger deflections across all boundary conditions, and the highest deflection is observed under specific combinations of porosity and GPL distribution patterns subjected to asymmetric loads.
