Environmentally Conscious Design of Upstream Crude Oil Supply Chain

Mathematical modeling for green supply chain considering product recovery capacity and uncertainty for demand

Competition in today's market is the most important concern of companies and producers in free markets. Buyers are also looking for higher quality and lower prices. Manufacturers should, therefore, reduce production costs and increase budgets for research and product development. On the other hand, the limitation of mineral resources in each country and in the world in general is a very important factor for increasing the price of raw materials which increases the cost of production of a product. In this study, a green aspect of decision-making, concurrent modeling for inventory-routing, and application of maximum entropy (ME) method for overcoming uncertainties of demands are applied to optimize the usage of raw materials and returning of defective products to the production cycle in a closed-looped supply chain under multi-period planning horizon. Also, dynamic modeling is used to balance the inventory level in all stages of the network that leads to optimum usage of the raw materials. For this purpose, the first objective function reduces production, transportation-routing, and inventory costs, and the second objective reduces greenhouse gas emissions through all levels of the network. Finally, this model is solved by using the exact solution method with the help of Gams software as well as the non-dominated sorting genetic algorithm II (NSGAII) and multi-objective particle swarm optimization (MOPSO) algorithm. Sensitivity analysis has been performed on failure rates, greenhouse gas emissions during recycling and production, and the optimistic-pessimistic coefficient of the ME solution method. Solution methods have been compared using several criteria, and the NSGAII method has finally obtained the best result. The results show that the manager should pay more costs in order to prevent backorder demands. Also, collecting the more defective products leads to increasing production amount since the collective products can return to the production line. Finally, it is required for the managers to control products' failure rate to optimize capacity usage in the model.

A sustainable mathematical model for design of net zero energy buildings

Energy is vital recourse for economic development of today's business. The services demanded of residential and commercial buildings require substantial energy use. Energy consumption in this sector has been growing in total, gradually. As a result the high emission of greenhouse gases is released and, hence, the saving energy with better building management have made a major priority of the energy and environment sectors throughout the world. In this direction, to reduce energy consumption and mitigate environmental impacts in buildings, net-zero energy buildings (NZEB) is a very effective solution. As a result, a multi-objective model is developed to identify the best combination of materials and construction options considering their related costs, energy efficiency, and environmental impacts of buildings, simultaneously. This sustainable model is presented to construct a building considering the construction costs and energy consumption of the design options. To design the NZEB, while minimizing costs and carbon emissions, use has been made of a combination of different types of active/heating and cooling systems and renewable equipment through such high-efficiency, effective, and updated technologies as the solar panel. Finally, the case study of a residential building with two scenarios is used to demonstrate the proposed framework. The results show that, for scenarios1 and 2 respectively using insulation thickness such as (wall, roof, and windows) and renewable equipment have the highest sustainable impact in NEBZ's performance.

Hydrophobic nano sponge for efficient removal of diesel fuel from water and soil

Diesel fuel (DF)-contamination remediation has aroused increasing concern in environmental field. In our work, nano sponge was modified by silylation of amino silicon oil (ASO) and aminopropyltriethoxysilane (APTES) to obtain hydrophobic nano sponge (SPAA). SPAA possessed a micro/nano network structure and could efficiently adsorb DF through hydrophobic polysiloxane group. The results revealed that SPAA could effectively remove DF and control its migration in water and soil under various conditions. Importantly, SPAA could inhibit the harmful effect of DF on the growth of plants, earthworms, and fish. Therefore, this work provides a promising and low-cost approach for removal of DF from water and soil, which might have a potential application value.

Biomass-Derived Porous Carbonaceous Aerogel as Sorbent for Oil-Spill Remediation

We prepared a cost-effective, environmentally friendly carbonaceuous oil sorbent with a lotus effect structure using a simple one-pot hydrothermal reaction and a mild modification process. The carbonaceous oil sorbent can rapidly, efficiently, and continuously collect oil in situ from a water surface. This sorbent was unlike traditional sorbents because it was not dependent on the weight and volume of the sorption material. The sorbent was also successfully used to separate and collect crude oil from the water surface and can collect organic solvents underwater. This novel oil sorbent and oil-collection device can be used in case of emergency for organic solvent leakages, as well as leakages in tankers and offshore drilling platforms.