scholarly journals An Imperfect Production–Inventory Model with Mixed Materials Containing Scrap Returns Based on a Circular Economy

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1275
Author(s):  
Rung-Hung Su ◽  
Ming-Wei Weng ◽  
Chih-Te Yang ◽  
Hsin-Ting Li

The implementation of scrap recovery activities has been shown to improve the financial performance of many firms, and this kind of circular economy (CE) is particularly evident in industries with green manufacturing (GM). In this paper, we consider an imperfect multiple-stage production system that manufactures paired products made from mixed materials containing scrap returns, in which the scrap returns are converted from defective products. The feed rates of scrap returns for two products are different, and the product with the higher feed rate is placed in the second order of the process to avoid unlimited accumulation of scrap returns. The proposed problem is formulated as a joint economic order quantity (EOQ) and economic production quantity (EPQ) model aimed at cost minimization. The decision variables of the proposed model include the production run time of two products, order quantity of new material, and the extent of investment in converted equipment. We also prove that the optimal solution exists uniquely and provide an algorithm for the computation of the optimal solution. Finally, a numerical example involving the pulp and paper manufacturing industry is provided to illustrate the solution process, and the results of its sensitivity analysis are also presented to show some managerial implications.

Author(s):  
P. K. Tripathy ◽  
Anima Bag

The purpose of the current paper is to determine an optimal order quantity so as to minimize the total cost of the inventory system of a business enterprise. The model is developed for deteriorating items with stock and selling price dependent demand under inflation without permitting shortage. Optimal solution is achieved by cost minimization strategy considering replenishment cost, purchase cost, holding cost and deterioration cost with a special approach to entropy cost for bulk size purchasing units. The effectiveness of the proposed model has been avowed through empirical investigation. Sensitivity analysis has been accomplished to deduce managerial insights. Findings suggest that an increased inflationary effect results in increment in the system total cost. The paper can be extended by allowing shortage. The model can be utilized in the business firms dealing with bulk purchasing units of electric equipments, semiconductor devices, photographic films and many more.


2012 ◽  
Vol 201-202 ◽  
pp. 967-970 ◽  
Author(s):  
Jia Qi Rong ◽  
Li Ling

Green Manufacturing and Recycling Economy is the basis for the sustainable development of human society, is also the direction for the future development of manufacturing industry. This article describes the concept of Green Manufacturing and Recycling Economy, analyses the work of Green Manufacturing processes, from product design, production, recycling-oriented three-pronged explained, and presents three suggestions of Green Manufacturing for circular economy, including extending the product life cycle, establishing enterprise's return goods processing center and strengthening cooperation with relevant manufacturers. Through these methods can enable enterprises to achieve the recycling of materials and energy, and enable enterprises to reduce production costs, improve core competitiveness.


Author(s):  
Moretti Emilio ◽  
Tappia Elena ◽  
Limère Veronique ◽  
Melacini Marco

AbstractAs a large number of companies are resorting to increased product variety and customization, a growing attention is being put on the design and management of part feeding systems. Recent works have proved the effectiveness of hybrid feeding policies, which consist in using multiple feeding policies in the same assembly system. In this context, the assembly line feeding problem (ALFP) refers to the selection of a suitable feeding policy for each part. In literature, the ALFP is addressed either by developing optimization models or by categorizing the parts and assigning these categories to policies based on some characteristics of both the parts and the assembly system. This paper presents a new approach for selecting a suitable feeding policy for each part, based on supervised machine learning. The developed approach is applied to an industrial case and its performance is compared with the one resulting from an optimization approach. The application to the industrial case allows deepening the existing trade-off between efficiency (i.e., amount of data to be collected and dedicated resources) and quality of the ALFP solution (i.e., closeness to the optimal solution), discussing the managerial implications of different ALFP solution approaches and showing the potential value stemming from machine learning application.


2006 ◽  
Vol 2006 ◽  
pp. 1-5 ◽  
Author(s):  
Yung-Fu Huang

Chiu studied the effect of service-level constraint on the economic production quantity (EPQ) model with random defective rate. In this note, we will offer a simple algebraic approach to replace his differential calculus skill to find the optimal solution under the expected annual cost minimization.


2004 ◽  
Vol 50 (3) ◽  
pp. 183-194 ◽  
Author(s):  
S.C. Stratton ◽  
P.L. Gleadow ◽  
A.P. Johnson

The impact of effluent discharges continues to be an important issue for the pulp manufacturing industry. Considerable progress has been made in pollution prevention to minimize waste generation, so-called manufacturing “process closure.” Since the mid-1980s many important technologies have been developed and implemented, many of these in response to organochlorine concerns. Zero effluent operation is now a reality for a few bleached chemi-thermomechanical pulp (BCTMP) pulp mills. In kraft pulp manufacturing, important developments include widespread adoption of new cooking techniques, oxygen delignification, closed screening, improved process control, new bleaching methods, and systems that minimize pulping liquor losses. Coupled to this is a commitment to reduce water use and maximize reuse of in-mill process streams. Some companies pursued bleach plant closure, and many have been successful in eliminating a portion of their bleaching wastewaters. However, the difficulties inherent in closing bleach plants are considerable. For many mills the optimal solution has been found to be a high degree of closure coupled with external biological treatment of the remaining process effluent. No bleach plants at papergrade bleached kraft mills are known to be operating effluent-free on a continuous basis. This paper reviews the important worldwide technological developments and mill experiences in the 1990s that were focused on minimizing environmental impacts of pulp manufacturing operations.


Procedia CIRP ◽  
2020 ◽  
Vol 90 ◽  
pp. 43-48
Author(s):  
Niken Kusumowardani ◽  
Benny Tjahjono

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3845
Author(s):  
Dorota Czarnecka-Komorowska ◽  
Wiktoria Kanciak ◽  
Mateusz Barczewski ◽  
Roman Barczewski ◽  
Roman Regulski ◽  
...  

This paper presents the contemporary problems of polymer waste recycling, mainly recycling cables from end-of-life vehicles. The authors developed a new material based on mixed polymer waste (ASR) modified with a ductile polymer, mainly recycled low-density polyethylene (rLDPE), to produce moisture-resistant boards with beneficial mechanical properties. The ASR-based compositions without and with homogenization process—including physical, chemical, and shear-assisted compatibilization—were successfully applied and verified by evaluating final recycled product properties. The results showed that recycled polyethylene (rLDPE) was effective as a modifier increasing tensile modulus and flexural strength compare to an ASR mixture. It was found that the adding 5 wt % of polyethylene-grafted maleic anhydride (PE-g-MAH) as a compatibilizer to the ASR mixture significantly increases the homogenization of the components in the ASR matrix. The optimal solution for management cable waste is the manufacture of ASR composites with homogenization using an internal mixer the adding 20 wt % of rLDPE and 5 wt % of PE-g-MAH to the mixed plastics cable waste. The results obtained demonstrate that the hot-pressing with the pre-blending with rLDPE and compatibilizer of the ASR based waste provides a high gain in mechanical and usage properties, enabling the circular economy of plastics from automotive cables.


2021 ◽  
Vol 11 (5) ◽  
pp. 138
Author(s):  
Vladimir Alexandrovich Kirik ◽  
Shanyi Cheng ◽  
Natalia Ivanovna Vyunova ◽  
Olga Vladimirovna Galustyan ◽  
Saida Sosoevna Gamisonija ◽  
...  

The article is devoted to education of future green engineers for achieving sustainable development in green manufacturing industry. It outlines that green engineering is an important industry which aim is to reduce consumption, to save resources, and to achieve sustainable development in manufacturing. Green manufacturing puts forward new requirements for the training future green engineers. The article reveals the concepts of educating future green engineers. Specifical attention is paid to the improvement of the teaching system training of future green engineers, strengthening the teaching staff, changing the teaching mode, strengthening teaching practice and practical training for achieving teaching goals. The authors conclude that it is necessary to clarify the goals of training of future green engineers, and to establish reform the teaching content of green engineering course.


2020 ◽  
Vol 30 (2) ◽  
pp. 237-250
Author(s):  
Aditi Khanna ◽  
P Priyamvada ◽  
Chandra Jaggi

Organizations are keen on rethinking and optimizing their existing inventory strategies so as to attain profitability. The phenomenon of deterioration is a common phenomenon while managing any inventory system. However, it could become a major challenge for the business if not dealt carefully. An investment in preservation technology is by far the most inuential move towards dealing with deterioration proficiently. Additionally, it is noticed that the demand pattern of many products is reliant on its availability and usability. Thus, considering demand of the product to be ?stock-dependent" is a more practical approach. Further, in case of deteriorating items, it is observed that the longer an item stays in the system the higher is its holding cost. Therefore, the model assumes the holding cost to be time varying. Hence, the proposed framework aims to develop an inventory model for deteriorating items with stock-dependent demand and time-varying holding cost under an investment in preservation technology. The objective is to determine the optimal investment in preservation technology and the optimal cycle length so as to minimize the total cost. Numerical example with various special cases have been discussed which signifies the effect of preservation technology investment in controlling the loss due to deterioration. Finally, the effect of key model features on the optimal solution is studied through sensitivity analysis which provides some important managerial implications.


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