This paper reports a new method to enhance the sensitivity of nanoparticle-based protein detection with X-ray fluorescence by exploiting the large volume reduction of hydrogel upon dehydration. A carboxylated agarose hydrogel with uniaxial microchannels is used to allow rapid diffusion of nanoparticles and biomolecules into the hydrogel and water molecules out of the hydrogel. Carboxylated hydrogels are modified to capture protein biomarkers and X-ray fluorescence nanoparticles (iron oxide nanoparticles) are modified with antibodies that are specific to protein biomarkers. The presence of protein biomarkers in solution binds the nanoparticles on the hydrogel channels. The dehydration of hydrogels leads to a size reduction of over 80 times, which increases the number of nanoparticles in the interaction volume of the primary X-ray beam and the intensity of characteristic X-ray fluorescence signal. A detection limit of 2 μg/mL for protein detection has been established by determining the number of nanoparticles using X-ray fluorescence.

Adsorption cooling and desalination (ACD) system powered by renewable energy has been considered as a promising solution to solve interconnected global problems such as freshwater scarcity, high-cost air conditioning, CO2 emission, and global warming. In this work, a new nanoporous silica was synthesized through a self-assembly process using a combination of ionic and non-ionic surfactants. The silica has shown unique pore structures, including high surface area and large pore volume, as well as ideal pore size distribution. The new silica was deposited (coated) over the ligaments of aluminum foam for use as a sorption bed. An uncoated aluminum foam packed with conventional silica RD (regular density) particles serves as a baseline sorption bed. The freshwater production rate and cooling power produced using the two sorbents were compared. Silica RD outperforms the new silica for cooling while the new silica is far better for desalination application. Insights for such results are provided.

Performance of two types of desiccant silica gel aluminum foam heat exchangers - desiccant coated heat exchanger (DCHE) and desiccant packed heat exchanger (DPHE) are evaluated experimentally and numerically. The DCHE is fabricated by coating silica gel over the ligaments of an aluminum foam, while the DPHE is built by packing an aluminum foam with silica particles. Equilibrium isotherms of the two heat exchangers are measured using the gravimetric approach. An open flow loop test rig is designed and built to measure the dry bulb temperature and humidity ratio of air upstream and downstream of the desiccant heat exchangers during the humidification and dehumidification process. In addition, a mathematical model is developed to investigate the heat and mass transfer process in the two desiccant heat exchangers. The experimental data obtained are used to validate the numerical results, and good agreement is established. The effects of heat exchanger length and inlet operating conditions on the performance of DPHE and DCHE are investigated. Experimental and numerical results indicate that the DPHE outperforms the DCHE in terms of cooling capacity and moisture removal capacity. It is observed that the performance of the DPHE is close to that of the DCHE in handling sensible heat loads but exceeds the latter in removing latent heat loads. The DPHE can provide dehumidified air for a longer time due to its higher moisture removal ability and higher density of the desiccant material compared to the DCHE.

Commonly used thermal analysis tools such as calorimeter and thermal conductivity meter are separated instruments and limited by low throughput, where only one sample is examined each time. This work reports an infrared based optical calorimetry with its theoretical foundation, which is able to provide an integrated solution to characterize thermal properties of materials with high throughput. By taking time domain temperature information of spatially distributed samples, this method allows a single device (infrared camera) to determine the thermal properties of both phase change systems (melting temperature and latent heat of fusion) and non-phase change systems (thermal conductivity and heat capacity). This method further allows these thermal properties of multiple samples to be determined rapidly, remotely, and simultaneously. In this proof-of-concept experiment, the thermal properties of a panel of 16 samples including melting temperatures, latent heats of fusion, heat capacities, and thermal conductivities have been determined in 2 min with high accuracy. Given the high thermal, spatial, and temporal resolutions of the advanced infrared camera, this method has the potential to revolutionize the thermal characterization of materials by providing an integrated solution with high throughput, high sensitivity, and short analysis time.