Notice of Retraction: Research on the multidimensional data models in the field of electrical and electronic waste product reverse logistics

2010 ◽  
Author(s):  
Liu Yang ◽  
Li Zhou
Keyword(s):  
Reverse Logistics ◽  
Electronic Waste ◽  
Waste Product ◽  
Data Models ◽  
Multidimensional Data ◽  
Electrical And Electronic Waste

scholarly journals The Proposition of a Mathematical Model for the Location of Electrical and Electronic Waste Collection Points

2020 ◽  
Vol 13 (1) ◽  
pp. 224
Author(s):  
Ítalo Ruan Barbosa de Aquino ◽  
Josenildo Ferreira da Silva Junior ◽  
Patricia Guarnieri ◽  
Lucio Camara e Silva
Keyword(s):  
Mathematical Model ◽  
Reverse Logistics ◽  
Electronic Waste ◽  
Waste Collection ◽  
Logistics System ◽  
Current Scenario ◽  
Electrical And Electronic Waste ◽  
The Cost ◽  
The Mathematical Model ◽  
Test Scenarios

Given the environmental impacts produced by the growing increase in waste electrical and electronic equipment (WEEE) and their current inadequate management, this article proposes a mathematical model to define the best location for installing WEEE collection points. The objective is to minimize the cost of the reverse logistics system concerning transportation, installation, opportunity cost, and distance between points and demand. We used a heuristic created from the greedy randomized adaptive search procedure and genetic algorithm meta-heuristics to solve the model, with part of the model variables being defined by another heuristic or by the JuMP v.0.21.2 and CLP Solver v.0.7.1 packages, to guarantee an optimal response to a subproblem of these variables. The model and its solver were written in the Julia Programming Language and executed in two test scenarios. In the first, three vehicles with small loads must collect at five points. In the second, a vehicle with greater available capacity must collect at five points. The results obtained show that the mathematical model and the heuristic are adequate to solve the problem. Thus, we understood that the proposed method contributes to the literature, given the criticality of the current scenario concerning the management of WEEE, and it can assist managers and public policymakers when providing inputs for decision-making related to the choice of the best location for installing collection points.

scholarly journals Recycling Potential for Non-Valorized Plastic Fractions from Electrical and Electronic Waste

Recycling ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 33
Author(s):  
Laura Strobl ◽  
Thomas Diefenhardt ◽  
Martin Schlummer ◽  
Tanja Leege ◽  
Swetlana Wagner
Keyword(s):  
Flame Retardants ◽  
Electronic Waste ◽  
Gel Permeation Chromatography ◽  
Scanning Calorimetry ◽  
Separation Processes ◽  
Melt Flow Rate ◽  
Density Fractions ◽  
Material Recycling ◽  
Other Substances ◽  
Electrical And Electronic Waste

This paper describes a study for waste of electrical and electronic equipment (WEEE) to characterise the plastic composition of different mixed plastic fractions. Most of the samples studied are currently excluded from material recycling and arise as side streams in state-of-the-art plastics recycling plants. These samples contain brominated flame retardants (BFR) or other substances of concern listed as persistent organic pollutants or in the RoHS directive. Seventeen samples, including cathode ray tube (CRT) monitors, CRT televisions, flat screens such as liquid crystal displays, small domestic appliances, and information and communication technology, were investigated using density- and dissolution-based separation processes. The total bromine and chlorine contents of the samples were determined by X-ray fluorescence spectroscopy, indicating a substantial concentration of both elements in density fractions above 1.1 g/cm3, most significantly in specific solubility classes referring to ABS and PS. This was further supported by specific flame retardant analysis. It was shown that BFR levels of both polymers can be reduced to levels below 1000 ppm by dissolution and precipitation processes enabling material recycling in compliance with current legislation. As additional target polymers PC and PC-ABS were also recycled by dissolution but did not require an elimination of BFR. Finally, physicochemical investigations of recycled materials as gel permeation chromatography, melt flow rate, and differential scanning calorimetry suggest a high purity and indicate no degradation of the technical properties of the recycled polymers.

scholarly journals Improved Simulated Annealing Based Network Model for E-Recycling Reverse Logistics Decisions under Uncertainty

2018 ◽  
Vol 2018 ◽  
pp. 1-17
Author(s):  
Lei Wang ◽  
Mark Goh ◽  
Ronggui Ding ◽  
Vikas Kumar Mishra
Keyword(s):  
Simulated Annealing ◽  
Reverse Logistics ◽  
Electronic Waste ◽  
Neighborhood Search ◽  
Generation Process ◽  
Candidate Solution ◽  
Novel Approach ◽  
Numerical Experimentation ◽  
The Government ◽  
Quantitative Importance

Electronic waste recycle (e-recycling) is gaining increasing importance due to greater environmental concerns, legislation, and corporate social responsibility. A novel approach is explored for designing the e-recycling reverse logistics network (RLN) under uncertainty. The goal is to obtain a solution, i.e., increasing the storage capacity of the logistics node, to achieve optimal or near-optimal profit under the collection requirement set by the government and the investment from the enterprise. The approach comprises two parts: a matrix-based simulation model of RLN formed for the uncertainty of demand and reverse logistics collection which calculates the profit under a given candidate solution and simulated annealing (SA) algorithm that is tailored to generating solution using the output of RLN model. To increase the efficiency of the SA algorithm, network static analysis is proposed for getting the quantitative importance of each node in RLN, including the static network generation process and index design. Accordingly, the quantitative importance is applied to increase the likelihood of generating a better candidate solution in the neighborhood search of SA. Numerical experimentation is conducted to validate the RLN model as well as the efficiency of the improved SA.

scholarly journals Analysis of the treatment of plastic from electrical and electronic waste in the Republic of Serbia and the testing of the recycling potential of non-metallic fractions of printed circuit boards

2017 ◽  
Vol 71 (3) ◽  
pp. 271-279
Author(s):  
Aleksandra Vucinic ◽  
Zeljko Kamberovic ◽  
Milisav Ranitovic ◽  
Tihomir Kovacevic ◽  
Irena Najcevic
Keyword(s):  
Chemical Composition ◽  
Printed Circuit Boards ◽  
Electronic Waste ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Mechanical Methods ◽  
The Republic ◽  
Electrical And Electronic Waste ◽  
Metallic Fractions

This paper presents the analysis of the quantity of plastic and waste printed circuit boards obtained after the mechanical treatment of electrical and electronic waste (E-waste) in the Republic of Serbia, as well as the recycling of non-metallic fractions of waste printed circuit boards. The aim is to analyze the obtained recycled material and recommendation for possible application of recyclables. The data on the quantities and treatment of plastics and printed circuit boards obtained after the mechanical treatment of WEEE, were gained through questionnaires sent to the operators who treat this type of waste. The results of the questionnaire analysis showed that in 2014 the dismantling of E-waste isolated 1,870.95 t of plastic and 499.85 t of printed circuit boards. In the Republic of Serbia, E-waste recycling is performed exclusively by using mechanical methods. Mechanical methods consist of primary crushing and separation of the materials which have a utility value as secondary raw materials, from the components and materials that have hazardous properties. Respect to that, the recycling of printed circuit boards using some of the metallurgical processes with the aim of extracting copper, precious metals and non-metallic fraction is completely absent, and the circuit boards are exported as a whole. Given the number of printed circuit boards obtained by E-waste dismantling, and the fact that from an economic point of view, hydrometallurgical methods are very suitable technological solutions in the case of a smaller capacity, there is a possibility for establishing the facilities in the Republic of Serbia for the hydrometallurgical treatment that could be used for metals extraction, and non-metallic fractions, which also have their own value. Printed circuit boards granulate obtained after the mechanical pretreatment and the selective removal of metals by hydrometallurgical processes was used for the testing of the recycling potential. Granulometric analysis as well analysis of chemical composition of obtained fractions was performed. Subsequently, the manual classification of different types of polymeric material contained in the granulate was made, and both the apparent specific gravity and the chemical composition of the classified types of polymeric materials were determined. Chemical composition of granulate was determined by X-Ray Fluorescence (XRF) using Thermo Scientific Niton XL 3t, while the identification of residual polymers was determined by the FTIR (Fourier Transform Infrared Spectroscopy) method on the Bomen MB 100 device in range 4000 to 400 cm?1. Based on the results of this study, it can be concluded that after the hydrometallurgical treatment of printed circuit boards, and the separation of metals that have the highest value, the residual non-metallic fraction have the utility value and can be used for various purposes, such as developing new polymer materials for technical purposes that have been investigated by many researchers and mentioned in this article.

Design and development of a fuzzy credibility-based reverse logistics network with buyback offers: A case study

2021 ◽  
pp. 0734242X2110452
Author(s):  
Masoud Amirdadi ◽  
Farzad Dehghanian ◽  
Jamal Nahofti Kohneh
Keyword(s):  
Reverse Logistics ◽  
Electronic Waste ◽  
Critical Issue ◽  
Product Recovery ◽  
Logistics Network ◽  
Waste Production ◽  
Reverse Logistics Network ◽  
Mashhad City ◽  
Recovery Approach

The ever-growing stream of waste production has become a critical issue for many metropolitan areas. An effective strategy to address this problem has been the concept of reverse logistics (RL). This paper seeks to develop an appropriate product recovery approach for electronic waste generated in an urban area. Consequently, we have proposed an integrated fuzzy RL model with buyback (BB) offers based on the condition of used-products (UPs) at the time of return. However, this strategy contains a significant challenge, which derives from unpredictability surrounding the return rate of UPs due to its dependency on multiple external factors. Hence, a novel fuzzy probability function is developed to approximate UPs’ chance of return. Besides that, the mathematical RL network’s inherent uncertainty prompted us to employ the fuzzy credibility-based method in the model. Afterward, the model’s objectives are locating and allocating collection centres to customer zones, determining flow between facilities and finding the optimal amount of gathered UPs and BB offers. Finally, we applied the model to a case study concerning product recovery in Mashhad city, Iran, and the results have proven its validity and utility.

Multidimensional Data Models and Aggregation

2000 ◽  
pp. 87-105 ◽  
Author(s):  
Matthias Jarke ◽  
Maurizio Lenzerini ◽  
Yannis Vassiliou ◽  
Panos Vassiliadis
Keyword(s):  
Data Models ◽  
Multidimensional Data

Logical and Physical Design of Spatial Non-Strict Hierarchies in Relational Spatial Data Warehouse

2019 ◽  
Vol 15 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Ferrahi Ibtisam Ibtisam ◽  
Sandro Bimonte ◽  
Kamel Boukhalfa
Keyword(s):  
Spatial Data ◽  
Data Models ◽  
Multidimensional Data ◽  
Bitmap Index ◽  
Spatial Concepts ◽  
Spatial Dimensions ◽  
Spatial Data Models ◽  
Spatial Data Warehouse ◽  
Spatial Hierarchy ◽  
The Cost

The emergence of spatial or geographic data in DW Systems defines new models that support the storage and manipulation of the data. The need to build an SDW and to optimize SOLAP queries continues to attract the interest of researchers in recent years. Several spatial data models have been investigated to extend classical multidimensional data models with spatial concepts. However, most of existing models do not handle a non-strict spatial hierarchy. Moreover, the complexity of the spatial data makes the execution time of spatial queries very considerable. Often, spatial indexation methods are applied to optimizing access to large volumes of data and helps reduce the cost of spatial OLAP queries. Most of existing indexes support predefined spatial hierarchies. The authors show, in this article, that the logical models proposed in the literature and indexing techniques are not suitable to non-strict hierarchies. The authors propose a new logical schema supporting the non-strict hierarchies and a bitmap index to optimize queries defined by spatial dimensions with several non-strict hierarchies.

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