Logistics of carpet recycling in the U.S.: designing the collection network

Efficient collection of post-consumer carpet is an important part of the carpet recycling process that helps to reduce the cost of recycled materials as well as provide sufficient volumes of carpet for recycling facilities. This paper focuses on the design of a collection network for carpet in the U.S. The location set covering optimization model formulated in the paper allows locating the minimum number of collection centers throughout the U.S. to reach a specific level of population coverage and as a result, a target collection rate. To solve real-scale instances of the problem, a novel randomized greedy heuristic is developed. The heuristic is shown to perform better than existing greedy heuristics in the literature. In addition, the paper presents the resulting nationwide carpet collection networks for different levels of population coverage. The results of the study can be used for U.S. carpet recycling policy-making decisions.     

Electrophysical method for evaluating the fracture surface energy of dielectric materials in contact with metal

A physical model is formulated and the method is substantiated for measuring the fracture surface energy of dieletric materials. An analogy between the distributions of electric field intensity and mechanical stresses close to the metal-dieletric surface contact is used.Translated from Izmeritelnaya Tekhnika, No. 10, pp. 52–56, October, 2004.     

Approach to modify the properties of titanium alloys for use in nuclear industry

This article discusses the metallurgical aspects of the modification of titanium alloys for use in the nuclear industry in the future. Irradiation leads to hardening, plastic instability and reduction in fracture toughness in Ti alloys. Sintered compositions Ti-6Al-4V, Ti-6Al-4V/LaB₆ have shown methods to reduce embrittlement. Residual porosity may serve as a temporary storage of products of nuclear decay H and He. High uniformity of the element distribution reduces the number of places predisposed to defect cluster formation. The plasticity reserve of Ti-6Al-4V/LaB₆ in comparison with international standards is ≈10%. The boron compounds to the partial absorption of neutrons fill the volume of residual pores in the material without degrading the properties of the matrix Ti-6Al-4V/LaB₆ alloy.     

Effect of the crystallization kinetic parameters on the structure and properties of a eutectic alloy of the LaB6–TiB2 system

The effect has been studied of the cooling rate and excess of boron on the formation of microstructures of LaB₆–TiB₂ reinforced ceramic composites during centrifugal sputtering in the argon atmosphere and during sputtering of the alloy melt onto a copper substrate in the helium atmosphere. It has been shown that the increase of the cooling rate to 10⁶ deg/s results in a decrease of diameters of composite material fibers to 0.1–0.15 μm. The decrease of the boron concentration from 2 to 1 wt % has been found to lead to an increase of diameters and decrease of the number of the titanium diboride fibers by a factor of 2–3.     

Calculation of the structural parameters of solid-state electronic devices

The effect of the electron subsystem on the chemical bond and the formation of the smallest solid particle (a cluster) is considered. A formula is given for determining its size, characterizing the distribution of the electric, temperature and mechanical fields in thin-layer heterogeneous structures. __________ Translated from Izmeritel’naya Tekhnika, No. 4, pp. 54–57, April, 2007.     

An Experimental-Theoretical Method of Measuring the Surface Energy of Polar Dielectrics

A physical model of the initial reversible stage of electrical breakdown is formulated, which provides a basis for a method of measuring the surface fracture energy of a thin dielectric layer of a metal-dielectric-metal structure at the instant of fracture.__________Translated from Izmeritel’naya Tekhnika, No. 4, pp. 57–60, April, 2005.     

Phase relations in the LaB<Subscript>6</Subscript>-MoB<Subscript>2</Subscript> system

LaB₆-MoB_2.2 alloys have been prepared at 2600°C in high-purity helium in a vacuum induction furnace. As found by microstructural analysis and x-ray diffraction, the components of this system form a eutectic. The microstructure of the eutectic has been studied. MoB_2.2 is shown to undergo a transformation during cooling, with the precipitation of submicron-sized Mo₂B₅ and α-MoB particles. For this reason, its microhardness increases with an increase in the melting temperature of the alloys because the diffusion rate rises with temperature.     

Optically induced switching in spin-crossover compounds: microscopic and macroscopic models and their relationship

We present the examination of light induced behavior of spin-crossover compounds. We focus on the switching phenomena between low-spin and high-spin states of the system. The connection between the Ising-like model and the macroscopic evolution equation has been analyzed. By means of numerical simulations, we found the dynamical potential changes, the corresponding light induced hysteresis, and the transient regimes. The statistical properties of the system in contact with a heat bath are shown in a stationary probability distribution.     

Thermal conductivity of cermets containing titanium carbide

Conclusions The thermal conductivity of TiC-Nb, TiC-Ta, TiC-Mo, and TiC-W cermets with metal contents of 25, 50, and 75 at.% was investigated at temperatures ranging from 20 to 1100°C. The thermal conductivity of the cermets was found to be much less than that of their metallic constituents. It was established that, at constant temperature, the thermal conductivity of the cermets increases in the order TiC-Nb< TiC-Ta相似文献