Gas Production from the Radiolysis of Water Adsorbed on ZnO Nanoparticles

The presence of a metal oxide surface can significantly alter the product yield distribution during the radiolysis of water with some metal oxides such as ZrO2 or CeO2, increasing the yield of H2 during the irradiation of water adsorbed on the oxide as compared to liquid water, while other oxides such as PuO2 decrease H2 yields. In this study, the γ-ray radiolysis of the ZnO/H2O system was investigated. Surprisingly, both O2 and H2 were produced in similar quantities. The production of O2 is unexpected as no, or negligible, amounts of O2 have been observed for the radiolysis of water adsorbed on other oxides. Molecular oxygen production is observed during the radiolysis of both wet and dry ZnO, indicating that the source of at least some of the O2 is the bulk oxide. The production of H2 due to the radiolysis of water adsorbed on ZnO is an order of magnitude greater than for pure water. This increase is likely due to an energy-transfer process from the oxide to the adsorbed water molecules. However, the radiolysis of aqueous suspensions of ZnO resulted in lower radiolytic H2 yields than for pure water

Excitation-energy dependence of the mechanism for two-photon ionization of liquid H2O and D2O from 8.3to12.4eV

This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/125/4/10.1063/1.2217738.Transient absorption measurements monitor the geminate recombination kinetics of solvated electrons following two-photonionization of liquid water at several excitation energies in the range from 8.3to12.4eV. Modeling the kinetics of the electron reveals its average ejection length from the hydronium ion and hydroxyl radical counterparts and thus provides insight into the ionization mechanism. The electron ejection length increases monotonically from roughly 0.9nm at 8.3eV to nearly 4nm at 12.4eV, with the increase taking place most rapidly above 9.5eV. We connect our results with recent advances in the understanding of the electronic structure of liquid water and discuss the nature of the ionization mechanism as a function of excitation energy. The isotope dependence of the electron ejection length provides additional information about the ionization mechanism. The electron ejection length has a similar energy dependence for two-photonionization of liquid D(2)O, but is consistently shorter than in H(2)O by about 0.3nm across the wide range of excitation energies studied

Whose campus, whose security? Students’ views on and experiences of security services and police on university campuses

In recent years, high-profile incidents and student activism have raised questions about how securitisation on university campuses is experienced by students, yet there is a stark absence of academic research on the topic. Whose campus, whose security? draws on three datasets: a national survey of 635 students, regional interviews with 30 students and data obtained through Freedom of Information requests. The study provides the first empirical account of students’ views on, and experiences of, security services and police on UK university campuses. In doing so, it deliberately centres student views and experiences to provide an evidence base for higher education institutions as they operationalise their commitments to the equality, diversity and inclusion agenda

Resurgence of a Nation’s Radiation Science Driven by Its Nuclear Industry Needs

From MDPI via Jisc Publications RouterHistory: accepted 2021-10-26, pub-electronic 2021-11-23Publication status: PublishedThis article describes the radiation facilities and associated sample preparation, management, and analysis equipment currently in place at the Dalton Cumbrian Facility, a facility which opened in 2011 to support the UK’s nuclear industry. Examples of measurements performed using these facilities are presented to illustrate their versatility and the breadth of research they make possible. Results are presented from research which furthers our understanding of radiation damage to polymeric materials, radiolytic yield of gaseous products in situations relevant to nuclear materials, radiation chemistry in light water reactor cooling systems, material chemistry relevant to immobilization of nuclear waste, and radiation-induced corrosion of fuel cladding elements. Applications of radiation chemistry relevant to health care are also described. Research concerning the mechanisms of radioprotection by dietary carotenoids is reported. An ongoing open-labware project to develop a suite of modular sample handling components suited to radiation research is described, as is the development of a new neutron source able to provide directional beams of neutrons

Molecular hydrogen production from amorphous solid water during low energy electron irradiation.

This work investigates the production of molecular hydrogen isotopologues (H2, HD, and D2) during low energy electron irradiation of layered and isotopically labelled thin films of amorphous solid water (ASW) in ultrahigh vacuum. Experimentally, the production of these molecules with both irradiation time and incident electron energy in the range 400 to 500 eV is reported as a function of the depth of a buried D2O layer in an H2O film. H2 is produced consistently in all measurements, reflecting the H2O component of the film, though it does exhibit a modest reduction in intensity at the time corresponding to product escape from the buried D2O layer. In contrast, HD and D2 production exhibit peaks at times corresponding to product escape from the buried D2O layer in the composite film. These features broaden the deeper the HD or D2 is formed due to diffusion. A simple random-walk model is presented that can qualitatively explain the appearance profile of these peaks as a function of the incident electron penetration