Optimizing the performance of thermionic devices using energy filtering

Conventional thermionic power generators and refrigerators utilize a barrier in the direction of transport to selectively transmit high-energy electrons. Here we show that the energy spectrum of electrons transmitted in this way is not optimal, and we derive the ideal energy spectrum for operation in the maximum power regime. By using suitable energy filters, such as resonances in quantum dots, the power of thermionic devices can, in principle, be improved by an order of magnitude.Comment: 3 pages, 2 figure

Humphrey Center News: Fall 1987 v. 2, no. 2

Newsletter of the Hubert H. Humphrey Cancer Research Center at Boston University School of Medicine

Sustainable CO2 adsorbents prepared by coating chitosan onto mesoporous silicas for large-scale carbon capture technology

In this article, we report a new sustainable synthesis procedure for manufacturing chitosan/silica CO2 adsorbents. Chitosan is a naturally abundant material and contains amine functionality, which is essential for selective CO2 adsorptions. It is, therefore, ideally suited for manufacturing CO2 adsorbents on a large scale. By coating chitosan onto high-surface-area mesoporous silica supports, including commercial fumed silica (an economical and accessible reagent) and synthetic SBA-15 and MCF silicas, we have prepared a new family of CO2 adsorbents, which have been fully characterised with nitrogen adsorption isotherms, thermogravimetric analysis/differential scanning calorimetry, TEM, FTIR spectroscopy and Raman spectroscopy. These adsorbents have achieved a significant CO2 adsorption capacity of up to 0.98 mmol g−1 at ambient conditions (P=1 atm and T=25 °C). The materials can also be fully regenerated/recycled on demand at temperatures as low as 75 °C with a >85 % retention of the adsorption capacity after 4 cycles, which makes them promising candidates for advanced CO2 capture, storage and utilisation technology

Humphrey Center News: Spring 1988 v. 3, no. 1

Newsletter of the Hubert H. Humphrey Cancer Research Center at Boston University School of Medicine

Humphrey Center News: Fall 1988 v. 3, no. 2

Newsletter of the Hubert H. Humphrey Cancer Research Center at Boston University School of Medicine

Humphrey Center News: Spring 1988 v. 3, no. 1

Newsletter of the Hubert H. Humphrey Cancer Research Center at Boston University School of Medicine

Humphrey Center News: Spring 1985 v. 1, no. 1

Newsletter of the Hubert H. Humphrey Cancer Research Center at Boston University School of Medicine