Photon and proton induced fission on heavy nuclei at intermediate energies
We present an analysis of fission induced by intermediate energy protons or photons on actinides. The 660 MeV proton induced reactions are on 241 Am, 238 U, and 237 Np targets and the Bremmstrahlung-photons with end-point energies at 50 MeV and 3500 MeV are on 232 Th and 238 U targets. The study was performed by means of the Monte Carlo simulation code CRISP. A multimodal fission extension was added to the code within an approach which accounts for the contribution of symmetric and asymmetric fission. This procedure allowed the investigation of fission cross sections, fissility, num- ber of evaporated nucleons and fission-fragment charge distributions. The comparison with experimental data show a good agreement between calculations and experiments.
Measurement of the total cross section for 238U photofission in the nucleon resonance region
Abstract We present the results of the photofission cross section for 238 U measured between 200 and 1200 MeV. In the ‡ region our results agree with existing data on the total photoabsorption cross section, while at higher energy they show no evidence of the higher nucleon resonances, clearly seen in the photon absorption on the photon, and a damping of the absolute value.
Urea removal strategies for dialysate regeneration in a wearable artificial kidney.
The availability of a wearable artificial kidney (WAK) that provides dialysis outside the hospital would be an important advancement for dialysis patients. The concept of a WAK is based on regeneration of a small volume of dialysate in a closed-loop. Removal of urea, the primary waste product of nitrogen metabolism, is the major challenge for the realization of a WAK since it is a molecule with low reactivity that is difficult to adsorb while it is the waste solute with the highest daily molar production. Currently, no efficient urea removal technology is available that allows for miniaturization of the WAK to a size and weight that is acceptable for patients to carry. Several urea removal strategies have been explored, including enzymatic hydrolysis by urease, electro-oxidation and sorbent systems. However, thus far, these methods have toxic side effects, limited removal capacity or slow removal kinetics. This review discusses different urea removal strategies for application in a wearable dialysis device, from both a chemical and a medical perspective.