Hierarchical structure of a green supply chain
ساختار سلسله مراتبی یک زنجیره تأمین سبز-2021
Since the past decades, environmental challenges have been increasing due to pollution and production costs. For sustainable development, a green supply chain integrates the sustainable environmental process into the tradi- tional supply chain, reducing the cost of production, spur economic growth, and solving ecological issues. Thus, exploring the feasible design of green supply chain systems becomes an essential requirement for industry and commercial organizations. However, the green supply chain system usually integrates various systems currently used by the participants of supply chains. The design of such a large-scale system is quite costly through the conventional discrete event simulation-based approaches. Moreover, formal modelling method (e.g. Petri nets), as an alternative approach, provides formal and efficient support to model creation and analysis. However, the Petri nets cannot achieve compositional modelling, particularly for large-scale and complex systems, e.g., the green supply chain system. For improved compositionality, this paper proposes a hybrid modelling technique to integrate the compositional feature into Petri nets by combining with process algebra due to its superior capability in compositional modelling. The hybrid technique supports the modelling with Petri nets at first. It sorts the incidence matrix of Petri nets’ models to retrieves the mapping relation between Petri nets and performance evaluation process algebra (i.e. PEPA, a formal modelling method based on process algebra), which represents the compositional structure of Petri-net models. Hence, a compositional-structure constructing algorithm is designed to obtain all qualified PEPA hierarchical sub-models based on Petri net models, which combines Petri nets’ usability and the compositionality of PEPA for creating a novel and enhanced formal modelling technique that is particularly suitable for systems such as green supply chain systems.
Keywords: Green supply chains | Petri nets | Performance evaluation process algebra | Hierarchical structures | Compositionality
Highly thermo-conductive yet electrically insulating material with perpendicularly engineered assembly of boron nitride nanosheets
مواد بسیار رسانای حرارتی و در عین حال عایق الکتریکی با مونتاژ عمودی مهندسی شده نانوصفحات نیترید بور-2021
With rapid evolution of advanced microelectronic devices, thermally conductive polymeric materials with impressive through-plane thermal conductivity (κ⊥) and remarkable electrical insulating properties are urgently demanded for efficient thermal management. Assembly of boron nitride nanosheets (BNNS) into polymer matrix with vertically interconnected conformation was usually adopted. However, impeded by inferior oriented degree and insufficient overlapped interconnection of BNNS, polymer/BNNS nanocomposites still suffered from a limited enhancement of κ⊥. In this work, we firstly prepared regenerated cellulose (RC)/BNNS filaments with high thermal conductivity via wet-spinning method. Then, a tailored polydimethylsiloxane (PDMS)/(RC/BNNS) filaments nanocomposite with hierarchical assembled architectures is successfully fabricated with customizedmold vacuum impregnation. Numerous bunches of microscopical hybrid filaments penetrate through the nanocomposite from the bottom to the up, while vertically aligned microscopical BNNS with efficient filler interconnections confined within filaments provide many uniaxial thermal pathways. Attributed to tactfully engineered phonon pathways, the as-prepared material exhibits a remarkable κ⊥ up to 5.13 W/m K at 27.05 vol% BNNS loading, outperforming the characters in most literatures. Along with excellent electrical resistance and extraordinary thermal management performances, this type of nanocomposite with hierarchical structures provides an effective strategy to thickness-direction heat transfer issues of electronic devices.
Keywords: Through-plane thermal conductivity | Polymer | Boron nitride nanosheets | Vertical orientation
Hybrid modeling and empirical analysis of automobile supply chain network
مدل سازی هیبرید و تجزیه و تحلیل تجربی شبکه زنجیره تامین خودرو-2017
Based on the connection mechanism of nodes which automatically select upstream and downstream agents, a simulation model for dynamic evolutionary process of consumer driven automobile supply chain is established by integrating ABM and discrete modeling in the GIS-based map. Firstly, the rationality is proved by analyzing the consistency of sales and changes in various agent parameters between the simulation model and a real automobile supply chain. Second, through complex network theory, hierarchical structures of the model and relationships of networks at different levels are analyzed to calculate various characteristic parameters such as mean distance, mean clustering coefficients, and degree distributions. By doing so, it verifies that the model is a typical scale-free network and small-world network. Finally, the motion law of this model is analyzed from the perspective of complex self-adaptive systems. The chaotic state of the simulation system is verified, which suggests that this system has typical nonlinear characteristics. This model not only macroscopically illustrates the dynamic evolution of complex networks of automobile supply chain but also microcosmically reflects the business process of each agent. Moreover, the model construction and simulation of the system by means of combining CAS theory and complex networks supplies a novel method for supply chain analysis, as well as theory bases and experience for supply chain analysis of auto companies.
Keywords: Complex network | Complex self-adaptive system | Automobile | Supply chain | Hybrid modeling |Empirical analysis
Adaptation strategies for water supply management in a drought prone Mediterranean river basin: Application of outranking method
استراتژی های انطباق برای مدیریت تامین آب در حوضه رودخانه مدیترانه مستعد خشکسالی: استفاده از روش فرارتبه-2016
The regional water allocation planning is one of those complex decision problems where holistic approach to water supply management considering different criteria would be valuable. However, multi-criteria decision making with diverse indicators measured on different scales and uncertainty levels is difﬁcult to solve. Objective of this paper is to develop scenarios for the future imbalances in water supply and demand for a water stressed Mediterranean area of Northern Spain (Tarragona) and to test the applicability and suitability of an outranking method ELECTRE-III-H for evaluating sectoral water allocation policies. This study is focused on the use of alter- native water supply scenarios to fulﬁl the demand of water from three major sectors: domestic, industrial and agricultural. A detail scenario planning for regional water demand and supply has been discussed. For each future scenario of climate change, the goal is to obtain a ranking of a set of possible actions with regards to different types of indicators (costs, water stress and environmental impact). The analytical method used is based on outranking models for decision aid with hierarchical structures of criteria and ranking alternatives using partial preorders based on pairwise preference relations. We compare several adaptation measures including alternative water sources (reclaimed water and desalination); inter basin water transfer and sectoral demand management coming from industry, agriculture and domestic sectors and tested the sustainability of management actions for different climate change scenarios. Results have shown use of alternative water resources as the most reliable al- ternative with medium reclaimed water reuse in industry and agriculture and low to medium use of desalination water in domestic and industrial sectors as the best alternative. The proposed method has several advantages* Corresponding author.E-mail address: email@example.com (V. Kumar).http://dx.doi.org/10.1016/j.scitotenv.2015.06.062 0048-9697/© 2015 Elsevier B.V. All rights reserved.such as the management of heterogeneous scales of measurement without requiring any artiﬁcial transformation and the management of uncertainty by means of comparisons at a qualitative level in terms of the decision maker preferences.© 2015 Elsevier B.V. All rights reserved.
Keywords: Multicriteria analysis | ELECTRE-III-H | Water allocation problem | Water demand scenario | Catchment management