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Conventional small-scale adsorption chillers generally employ silica-gel/water or zeolite/water working pairs given the relatively high level of mesoporosity and water affinity in these adsorbent materials. However, the coefficient of performance (COP) and specific cooling power (SCP) evaluated for the adsorption chiller using these adsorbent/adsorbate pairs cannot be still considered practically feasible in the context of a commercial system. Metal organic frameworks (MOFs) are not only characterized by much higher water adsorption capacities than these materials, but also can be mass-produced using much simpler methods than the template-assisted synthesis routes of most zeolites. However, the low intrinsic thermal conductivity of these materials limits their use as adsorbents in commercial-scale adsorption chillers. In this study, a novel composite composed of multi-walled carbon nanotubes (MWCNTs) incorporated in a MIL-100(Fe) framework has been synthesized using a molecular-level mixing process. The resulting composite, with varying volume fraction of MWCNTs, has been characterized for microstructure, degree of crystallinity, thermal stability, water sorption kinetics and hydrothermal cyclic stability for potential use as an adsorbent in commercial adsorption chillers.

Metal and ceramic matrix composites have been developed to enhance the stiffness and strength of metals and alloys, and improve the toughness of monolithic ceramics, respectively. It is possible to further improve their properties by using nanoreinforcement, which led to the development of metal and ceramic matrix nanocomposites, in which case, the dimension of the reinforcement is on the order of nanometer, typically less than 100 nm. However, in many cases, the properties measured experimentally remain far from those estimated theoretically. This is mainly due to the fact that the properties of nanocomposites depend not only on the properties of the individual constituents, i.e., the matrix and reinforcement as well as the interface between them, but also on the extent of nanoreinforcement dispersion. Therefore, obtaining a uniform dispersion of the nanoreinforcement in the matrix remains a key issue in the development of nanocomposites with the desired properties. The issue of nanoreinforcement dispersion was not fully addressed in review papers dedicated to processing, characterization, and properties of inorganic nanocomposites. In addition, characterization of nanoparticles dispersion, reported in literature, remains largely qualitative. The objective of this review is to provide a comprehensive description of characterization techniques used to evaluate the extent of nanoreinforcement dispersion in inorganic nanocomposites and critically review published work. Moreover, methodologies and techniques used to characterize reinforcement dispersion in conventional composites, which may be used for quantitative characterization of nanoreinforcement dispersion in nanocomposites, is also presented.

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Research shows that mechanical properties of parts produced using fused deposition modeling (FDM) are inferior when compared to parts produced using conventional techniques such as injection molding. Efforts have been made in recent years to improve mechanical properties by reinforcing the parts with high strength fibers. This has been achieved by either modifying FDM setups to extrude fibers with thermoplastics and fabricate continuous fiber reinforced thermoplastic composites (CFRTPCs) or employing manual techniques subsequent to part production. Existing CFRTPCs fabrication procedures have limitations of fiber exposure to environment, no direct control method for volume fraction, and poor surface finish. This research work is focused on improving the process of producing CFRTPCs by addressing these limitations using a dual extruder FDM setup. The process developed was tested for its feasibility using Kevlar fiber as reinforcement for commercially available ABS, PLA, PLA-C, and PLA-Cu thermoplastic fibers. Taguchi L16 orthogonal array was used to design experiments, while tensile and flexural testing was performed to determine mechanical properties achieved. Tensile strength was improved up to 3 times the baseline value of thermoplastics, while flexural strength was improved up to 1.6 times. This technique can further the goal of developing CFRTPCs, on industrial level, using FDM with better control over volume fraction and fiber layup.

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