Wastewater treatment has been a challenge for beverage companies in recent years which has led them to establish specific units to purify the expired returning items before agricultural uses or disposal. This issue has never been studied from the perspective of inventory and production management. This paper proposes an inventory formulation in the case of Behnoush beverage company in Iran to determine the replenishment cycle and the optimal selling price of items when: (a) items deteriorate continuously and have their specific expiration dates, (b) a proportion of items that are expired are moved to the company and after the process of wastewater treatment, and (c) a trade credit period is offered to the buyer to make encouragement for ordering in larger quantities. Optimality conditions for the total cost function are elaborated. Thereafter, numerical experiments are adopted for validation. Eventually, managerial implications are outlined and findings of the study are summarized.@en

The incorporation of payment schemes and imperfect production has received considerable attention in the literature on inventory management; however, researchers have rarely considered these two challenges concurrently. The significance of employing both imperfect production and delay in payment is that both of these challenges affect the profit obtained directly. The total obtained profit can be mitigated by increasing the waste and reducing the number of sold perfect items and delay in payment stimulates the buyers to purchase items and settle their accounts in a specific period. This paper proposes a three-echelon inventory model that (a) Imperfect production is permissible; (b) Inspectors make errors during the inspection process and the errors can be diminished by learning from their previous performance; (c) It is practical to categorize customers into new and old types when old customers are prioritized to receive a full trade credit. As the retailer learns from the experience of screening, the probability of misclassification errors and inspection time decrease for two distinct cases of delay in payment to provide optimal replenishment and promotional decisions. To make a better connection to practical issues, a case study is elaborated. To validate the mathematical model, the impact of the inspector's learning on variables and the total profit is compared in different cases. The analysis shows that it is beneficial for the retailer to make shorter contracts, particularly with new customers to maximize the expected total profit per unit time. Eventually, a numerical experiment is conducted for each subcase to illustrate the impact of learning and determining the optimal policy for the retailer, then some implications for future contributions are outlined.@en

Incorporation of environmental and quality considerations has made production and inventory models shift away from classical models to multi-facet models; however, proposing solutions to improve these considerations has been attended scarcely. Losing a specific number of items due to imperfect production is irrevocable. Inspection operations can detect the imperfect items to avoid reaching the items to the customer; however, inspectors are not faultless and they may detect the quality of some items with errors. To address this issue, quality improvement technologies that monitor the production progress to detect imperfection at the moment can be a favorable approach. On the other hand, carbon dioxide is emitted due to the operations related to production systems, and it is crucial to find means to mitigate emissions because of the sustainability responsibility of firms and governmental regulations in carbon capture. The main novelty of this study is determining how shortages can affect a sustainable inventory system of imperfect quality items considering both quality improvement and inspection process simultaneously. In fact, this study takes another step in this line of research and considers economic, environmental, and quality considerations of an inventory system simultaneously because of few discussions in this line of thought. Shortages are considered allowable and the model is solved under different shortage scenarios. Optimality conditions are developed as a solution procedure and the models are validated using numerical experiments. The results indicate that the scenarios with full backordering and lost sales lead to higher profit than the scenarios without shortages or with partial backordering.@en

Carbon emission regulations help firms to develop green inventory systems. Besides, lots of items perish because of deterioration. Therefore, controlling both carbon emissions and the deterioration of items becomes essential. Despite the importance of the contribution of these issues, a few works have attended the concepts simultaneously. To fill this gap, this paper proposes a production system considering carbon emissions and deterioration of items and utilises green and preservation technologies to control them, respectively. Moreover, as determining the selling price of items plays a crucial role in a production system, pricing is another issue that this paper concentrates on it. This paper determines the preservation technology investment and green technology investment with discrete values of the cycle length and selling price for an item which: (a) items deteriorate at a constant rate, and the investment in preservation technology is allowable to mitigate the number of deteriorated items, (b) carbon is emitted due to setup and holding the items and the manufacturer follows carbon cap-and-trade regulation and invests on emission reduction, (c) a price-dependent demand is utilised to evaluate the selling price in optimal value. To validate the mathematical model, numerical examples for all cases are exposed.@en

Perishing of the items in an inventory model has always been a crucial issue for beverage companies. Besides, some items not only perish but also have specific expiration dates. To manage the inventory-in-hand, proposing a delay in payment is usually an appropriate solution. Also, beverage companies encounter sustainable policies that are regulated to dispose of waste without damaging the environment. These regulations lead companies to establish waste treatment units in their companies to purify the obsolete items before disposing of them. Despite the importance of this challenge in practice, no research has been made to contribute to these issues. To fill the mentioned gap in the literature, this paper proposes an inventory model for perishable items which: (a) items perish continuously and have specific expiration dates, (b) a single-level trade credit is offered to the customer to stimulate the demand, and (c) waste treatment policy is considered for the beverage company to purify the returning items before disposing of them. To develop our work in practice, the case study of Behnoush Beverage Company is considered and a real domain dataset is utilized. To validate the proposed mathematical model, a sensitivity analysis is developed. Eventually, managerial implications are outlined and the findings are concluded.@en