Gold nanoparticles provide an excellent platform for biological and material applications due to their unique physical and chemical properties. However, decreased colloidal stability and formation of irreversible aggregates while freeze-drying nanomaterials, limits their use in real world applications. Here, we report a new generation of surface ligands based on a combination of short oligo (ethylene glycol) chain and zwitterions capable of providing non-fouling characteristics, while maintaining colloidal stability and functionalization capabilities. Additionally, conjugation of these gold nanoparticles with avidin can help developing a universal toolkit for further functionalization of nanomaterials.

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SUMMARYA novel solar adsorption chiller intended for domestic use is presented. The chiller can be integrated with existing solar systems based on flat plate collectors, and, contrary to commercial chillers, it operates continuously. A detailed analysis of both the simple and the heat-integrated cycle is carried out so as to select the optimal adsorbent and operating conditions. The employed integral thermodynamic model takes into account the inert masses that limit the performance of the chiller, such as the metal frame, the thermofluid, and the non-adsorbed steam, by introducing heat capacity effects. Given the adsorption equilibrium data, the energy balances, the performance, and the useful thermal loads of the system can be calculated at any operating conditions. The results indicate that silica gel Type A is a more efficient adsorbent compared to silica gel Type RD or Type 3A. Furthermore, the total porosity has a slight effect on system performance, while optimal operation can be achieved when the condenser temperature is less than 326 K and the evaporator temperature greater than 280 K.