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 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.
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.
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.
This review provides a focused evaluation of recent advances in the green upcycling of polyethylene terephthalate (PET) waste into polymer quantum dots (PQDs), emphasizing strategies that transform discarded plastic into high-value nanomaterials. It systematically examines environmentally friendly approaches for converting PET waste into PQDs and analyzes their impact on the electronic, optical and surface properties that determine performance in environmental and energy applications. The novelty lies in the comparative assessment of upcycling and synthesis pathways, revealing how processing routes control structural and physicochemical features of PQDs. These features directly enhance performance in two key domains: (i) improved fuel cell electrodes through PQD-assisted charge transfer and reactivity, and (ii) advanced membranes with high adsorption capacity for heavy metals (Hg, Pb, Cd, Cr) in aquaculture wastewater. The review also highlights the dual environmental benefit of plastic waste reduction and toxic metal remediation. Furthermore, it discusses how molecular-level control over PQD structure and surface chemistry can optimize electrochemical activity and metal-binding selectivity, advancing both energy conversion and environmental safety. By synthesizing the latest research, this work identifies challenges and future directions, guiding the sustainable design of PET-derived PQDs under green chemistry and circular economy principles.
Managing industrial by-products remains a critical environmental challenge due to their potential as a significant source of pollution. This study proposes a novel waste valorization strategy that utilizes ground granulated blast-furnace slag (GGBS) for the effective stabilization of problematic loess soils. The performance of this strategy was rigorously evaluated through a comprehensive experimental program. Samples treated with varying dosages of GGBS and traditional lime were subjected to mechanical tests (UCS, CP, UPV), successive freeze–thaw cycles (FTCs), and advanced microstructural analyses (XRD, FTIR, SEM, BET). Environmental safety was assessed via inductively coupled plasma (ICP) analysis to investigate heavy metal immobilization. The results demonstrated that the GGBS-based composite effectively solidified hazardous elements (As, Cd, Ni, Cr, Pb), significantly reducing their mobility and bioaccessibility. Technically, the optimal GGBS dosage not only surpassed lime in enhancing soil strength and ductility but also reduced the collapse potential from “severe” to “slight”. A quantitative sustainability assessment revealed that this shift to GGBS results in a remarkable reduction of over 90
