This paper evaluates a large-scale appliance replacement program in Mexico that from 2009 to 2012 helped 1.9 million households replace their old refrigerators and air conditioners with energy-efficient models. Using household-level billing records from  the universe of Mexican residential customers, we find that refrigerator replacement reduces electricity consumption by 8 percent, about one-quarter of what was predicted by ex ante analyses. Moreover, we find that air conditioning replacement actually increases electricity consumption. Overall, we find that the program is an expensive way to reduce externalities from energy use, reducing carbon dioxide emissions at a program cost of over $500 per ton. (JEL L68, L94, O12, O13, Q41, Q54)

No abstract

A new class of materials termed magnetorheological elastomers (MREs) are developed that respond to externally imposed magnetic fields. Magnetic particles are embedded in viscoelastic solids or liquid elastomeric precursors. This kind of composite demonstrates a unique combination of good magnetic controllability and elastic properties. Polybutadiene (hydrocarbon based) based polyurethane MREs are developed because of their thermooxidative, hydrolytic, and chemical resistance. The structure-property relationships of polyurethaneMREs are investigated using several characterization techniques. Morphological features such as interdomains of soft and hard segments are identified with tappingmode atomic force microscopy. The thermal and mechanical behavior is evaluated with dynamic mechanical analysis, differential scanning calorimetry, and stressstrain tests.

Magnetorheological materials have been used in many applications in recent years. To develop new materials, polyurethane and silicone polymer gels were investigated. Rheology is qualitatively controlled for each system by controlling the concentration of reactants and diluents. The resulting polymers have solid, gel, or liquid states, depending on the crosslinking and dilution. The gels were characterized through kinetic analysis. Differential scanning calorimetry (DSC) was used with analysis methods to find the kinetic properties for diluted and undiluted polyurethane systems. Heat of reaction, order of reaction, preexponential constant, and activation energy were obtained from the experimental DSC data.

Magnetorheological Elastomers (MREs) are synthesized from silicone RTV (room temperature vulcanizing) elastomer with magnetically soft iron particles. The iron particle concentration of the MREs is 70 wt %. To reduce the effect of oxidation on the MREs, the ATRP technique is used for surface polymerization of iron particles with fluorinated styrene as monomer. The mechanical properties of MREs are characterized using a mechanical testing instrument, and the surface coated polymer is characterized using Fourier transform infrared spectroscopy (FTIR), X-ray energy dispersive spectrometry (XEDS), differential scanning calorimetry (DSC), and the alignment of iron particles within MRE was characterized using scanning electron microscopy (SEM). The MRE samples are characterized using the mechanical testing instrument at 0 Tesla (off-state) and applied magnetic field from 0.46 Tesla to 0.62 Tesla (on-state). The required force at 0.62 Tesla increased approx. 3% to achieve 20% strain after 72 h of oxidation for surface coated MRE. On the other hand, the required force for non-surface coated MREs at 0.62 Tesla increased up to 17% to achieve 20% strain after 72 h of oxidation. MREs with surface coated iron particles have higher oxidation stability based on the force-displacement test results, and MREs have excellent potential to be used as intelligent materials with high durability for a vibration isolator. V C 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: [934][935][936][937][938][939][940][941][942] 2010