Materials recycling and industrial ecology.

Lally School of Management and Technology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA.
Nature Material (Impact Factor: 36.43). 05/2004; 3(4):199-201. DOI: 10.1038/nmat1101
Source: PubMed

ABSTRACT New legislation has been passed in an attempt to minimize industrial waste and promote recycling. What does this mean for materials science?

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    ABSTRACT: Polytetrafluoroethylene (PTFE) composites filled with PTFE waste offer interesting combination of tribological properties and low cost. PTFE composites waste was mechanically cut and sieved into powders. PTFE composites filled with PTFE waste powders were prepared by compression molding. Friction and wear experiments were carried out in a reciprocating sliding tribotester at a reciprocating frequency of 1.0 Hz, a contact pressure of 5.5 MPa, and a relative humidity of (60 ± 5)%. PTFE materials slid against a 45 carbon steel track. Results showed that a PTFE composite (B) filled with 20 wt % PTFE waste exhibited a coefficient of steady-state friction slightly higher than that of unfilled PTFE (A), while wear resistance over two orders of magnitude higher than that of unfilled PTFE (A). Another PTFE composite filled with PTFE waste and alumina nanoparticles exhibited the highest wear resistance among the three PTFE materials. This behavior originates from the effective reinforcement of PTFE waste as a filler. It was experimentally confirmed that the low cost recycling of PTFE waste without by-products is feasible. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1035–1041, 2007
    Journal of Applied Polymer Science 01/2007; 103(2):1035 - 1041. DOI:10.1002/app.25296 · 1.64 Impact Factor
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    ABSTRACT: Environmental concerns and government regulations have encouraged/forced real-world supply chains to take back used product for recycle. A smart supply chain should therefore leverage significantly on the returned “used products” to produce new products at nominal cost and time. In such closed loop supply chains, the crucial challenge is to synchronize the used products recycling system, the production facility and the new product distribution system in the presence of uncertain customer demands and used product returns. The main motivation of this study is to improve the performance of closed loop supply chains using a divide and conquer optimization scheme. In this paper, it is shown that the manner in which the closed loop supply chain is divided into various subsystems, the way in which interactions between the subsystems are handled and the optimization sequence adopted can help to improve the profitability of the supply chain with minimal computational load. Comparisons between the proposed method and traditional single objective optimization are made to illustrate the advantages of the divide and conquer approach to closed loop supply chain optimization.
    Industrial & Engineering Chemistry Research 11/2013; 52(46):16267–16283. DOI:10.1021/ie400742s · 2.24 Impact Factor
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    ABSTRACT: In Italy, reclamation of asbestos-containing materials (ACM) such as friable asbestos and cement-asbestos is accomplished by their removal, packaging and dumping in controlled landfills. An alternative way to landfill disposal is the thermal transformation of ACM and recycling of the transformation product as secondary raw material. The aim of this work is to integrate preliminary X-ray diffraction and microscopic investigations on the secondary raw material described earlier with a detailed study on the product of transformation at 1200 �C of friable chrysotile-asbestos and cement-asbestos, using (micro)Raman, (micro)FTIR, 57Fe Mo¨ssbauer and XANES at the Fe K-edge. Micro-Raman spectra reveal that the absorption bands generated by chrysotile are no longer present in the high-temperature products, and this is further confirmed by micro-FTIR results. In the core of the former fibres of loose chrysotile asbestos, the newly formed phases are olivine and enstatite, whereas the product of transformation of cement-asbestos is composed of olivine together with several other phases such as hematite and (Ca, Mg, Al)-silicates. The Mo¨ssbauer absorption spectra of raw chrysotile reveal that iron is contained in a paramagnetic phase (40 %) as well as in accessory magnetite (60 %). The paramagnetic contribution, attributed to chrysotile, is represented by Fe2þ (10 % of Fetot) and Fe3þ (30 % of Fetot), both octahedrally coordinated. The spectrum of thermally treated chrysotile clearly shows that the magnetic phases are now oxidized magnetite/maghemite and hematite, and the paramagnetic contribution is quite unaltered, though likely due to the newly formed olivine. The spectrum of untreated cement-asbestos has no evidence of accessory magnetic phases and is made of Fe2þ (15%of Fetot) and Fe3þ (85%of Fetot), both octahedrally coordinated. In the thermally treated sample all iron is oxidized, but a phase transition occurred, because Fe3þ is tetrahedrally coordinated. Also XANES spectra show that in all samples the dominant iron oxidation state is 3þ. XANES data on standard chrysotile are compatible with the possible presence of magnetite. In the high-temperature product of cement-asbestos, the high intensity of the pre-edge peak is comparable with that of the reference compound Fe-silicalite, with ferric iron hosted in the framework. This result indicates that in this product ferric iron is likely hosted in a crystalline phase in four-fold coordination, in agreement with Mo¨ssbauer spectroscopy results. Such crystalline phase could be Fe-bearing akermanite-gehlenite.
    European Journal of Mineralogy 08/2010; 22(4-4):535-546. DOI:10.1127/0935-1221/2010/0022-2038 · 1.51 Impact Factor


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