Pickering emulsions possess many advantages over traditional surfactant stabilized emulsions. For example, Pickering emulsions impart better stability against coalescence and, in many cases, are biologically compatible and environmentally friendly. These characteristics open the door for their use in a variety of industries spanning petroleum, food, biomedicine, pharmaceuticals, and cosmetics. Depending on the application, rapid, but controlled stabilization and destabilization of an emulsion may be necessary. As a result, Pickering emulsions with stimuli-responsive properties have, in recent years, received a considerable amounts of attention. This paper provides a concise and comprehensive review of Pickering emulsion systems that possess the ability to respond to an array of external triggers, including pH, temperature, CO2 concentration, light intensity, ionic strength, and magnetic field. Potential applications for which stimuli-responsive Pickering emulsion systems would be of particular value, such as emulsion polymerization, enhanced oil recovery, catalyst recovery, and cosmetics, are discussed.

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Generation 6.0 polyamidoamine (G6 PAMAM) dendrimer-grafted cellulose nanocrystals (CNCs) (CNC− PAMAM) were synthesized and employed as supports for gold nanoparticles. The successful grafting of PAMAM dendrimers was confirmed by conductometric−potentiometric titration and pH-dependent ζ-potential analyses. Gold nanoparticles with diameters of approximately 2 to 4 nm were synthesized with the PAMAM dendrimers playing the role of nanoreactors and NaBH 4 as the reducing agent. More importantly, gold nanoparticles were successfully prepared at pH 3.3 with the PAMAM dendrimers playing the functional role of reducing agent. Temperature and the concentration of CNC−PAMAM had an impact on the resulting size of gold nanoparticles. The gold nanoparticles immobilized on CNC− PAMAM displayed superior catalytic properties toward the reduction of 4-nitrophenol to 4-aminophenol. The enhanced catalytic behavior may be attributed to the improved dispersity and accessibility of gold nanoparticles within the PAMAM dendrimer domain. This work has demonstrated the versatility of CNC−PAMAM, both as an effective nanoreactor and a reducing agent.

The work focuses on the experimental study of the heat diode mechanism in an Integrated Collector Storage Solar Water Heater (ICSSWH) for domestic applications. The solar device combines a horizontal cylindrical vessel with an asymmetric reflector trough (Compound Parabolic Concentrator-CPC). The cylindrical storage tank comprises two concentric cylindrical vessels: the outer absorbing vessel and the inner storage vessel. The annulus between the cylindrical vessels is partially depressurized and contains a small amount of water serving as Phase Change Material (PCM), which changes phase (mainly at low temperatures) thus producing vapor and creating a thermal diode transfer mechanism from the outer to the inner surfaces of the vessels. Several experimental results, including uncertainty analysis, are demonstrated through diagrams depicting temperature variations, mean daily efficiency and thermal losses coefficient. Additionally results from the variation of the temperature and the total pressure inside annulus are also presented. The results clearly show that the vapor's pressure plays the most important role regarding the thermal performance of the device.

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