Effect of high resistive barrier on earthing system

Substation earthing provides a low impedance path and carries current into ground under normal and fault conditions without adversely affecting continuity of service. Under a fault condition, the ground voltage may rise to a level that may endanger the public outside the vicinity of the substation. In such a case a high resistive barrier can be inserted around the vicinity of the substation to reduce the surface potentials immediately beyond the barrier. In this paper the effect of barrier on the overall performance of the earthing system has been investigated experimentally and computationally based on an earthing system consisted of combined grid and rods in a water tank. The effect of the position and depth of the barrier to the resistance of the earthing system and surface potentials in and around the substation have been examined

Subtleties in the quasi-classical calculation of Hawking radiation

he quasi-classical method of deriving Hawking radiation is investigated. In order to recover the original Hawking temperature one must take into account a previously ignored contribution coming from the temporal part of the action. This contribution plus a contribution coming from the spatial part of the action gives the correct temperature.Comment: 6 pages revtex. Honorable Mention in 2008 GRF essay contest, typos fixed, sign errors corrected. To be published in Special Issue of IJMP

Disabled people and the Internet: experiences, barriers and opportunities

The UK government aims to make all its information and transactions available electronically by 2005. General use of the Internet also continues to grow. This report investigates the Internet's barriers and benefits for disabled people, and considers whether it acts as a means to reduce their social exclusion. The study surveys the views and experiences of disabled people, both Internet users and non-users. Topics covered include: what the Internet is used for; use of and difficulties with assistive devices (special equipment and adaptations needed by some disabled people in order to use computers); how people learn to use the Internet; views of website accessibility; advantages and disadvantages of Internet usage. It also explores participants' restrictions on using the Internet, and people's reasons for not using it. There has been little previous research in this area, but the authors review the existing literature. The report finds that many practical problems - such as the cost of training, finding appropriate assistive devices, website accessibility - all inhibit Internet opportunities for many disabled people

New symmetry current for massive spin-3/2 fields

We present several new results which will be of value to theorists working with massive spin-3/2 vector-spinor fields as found, for example, in low and intermediate energy hadron physics and also linearized supergravity. The general lagrangian and propagator for a vector-spinor field in d-dimensions is given. It is shown that the observables of the theory are invariant under a novel continuous symmetry group which is also extended to an algebra. A new technique is developed for exploring the consequences of the symmetry and a previously unknown conserved vector current and charge are found. The current leads to new interactions involving spin-3/2 particles and may have important experimental consequences.Comment: 9 pages, references updated and minor change

Dissociation of the benzene molecule by UV and soft X-rays in circumstellar environment

Benzene molecules, present in the proto-planetary nebula CRL 618, are ionized and dissociated by UV and X-ray photons originated from the hot central star and by its fast wind. Ionic species and free radicals produced by these processes can lead to the formation of new organic molecules. The aim of this work is to study the photoionization and photodissociation processes of the benzene molecule, using synchrotron radiation and time of flight mass spectrometry. Mass spectra were recorded at different energies corresponding to the vacuum ultraviolet (21.21 eV) and soft X-ray (282-310 eV) spectral regions. The production of ions from the benzene dissociative photoionization is here quantified, indicating that C6H6 is more efficiently fragmented by soft X-ray than UV radiation, where 50% of the ionized benzene molecules survive to UV dissociation while only about 4% resist to X-rays. Partial ion yields of H+ and small hydrocarbons such as C2H2+, C3H3+ and C4H2+ are determined as a function of photon energy. Absolute photoionization and dissociative photoionization cross sections have also been determined. From these values, half-life of benzene molecule due to UV and X-ray photon fluxes in CRL 618 were obtained.Comment: The paper contains 8 pages, 9 figures and 4 tables. Accepted to be published on MNRAS on 2008 November 2

Do alcohol product labels stating lower strength verbal description, percentage alcohol‐by‐volume, or their combination affect wine consumption? A bar laboratory adaptive randomised controlled trial

A previous research study concluded that wine and beer labelled as lower in strength increase consumption compared with the same drinks labelled as regular strength. The label included both a verbal and numerical descriptor of strength. The present study aimed to estimate the effect of each of these label components. Adaptive, parallel group randomised controlled trial, comprising an internal pilot sample (N = 90) and a confirmatory sample (N = 57). University bar laboratory in London UK. One-hundred and forty-seven weekly wine drinkers were sampled from a nationally representative English panel. Participants were randomised to one of three groups to taste test wine in a bar-laboratory, varying only in the label displayed: (i) verbal descriptor only (Super Low); (ii) numerical descriptor only (4%ABV); and (iii) verbal descriptor and numerical descriptor combined (Super Low 4%ABV) [each group n = 49]. The primary outcome was total volume (ml) of wine consumed. Participants randomised to the numerical descriptor label group (4%ABV: M = 155.12ml, B = 20.30, 95% CI = 3.92, 36.69, p-value = 0.016) and combined verbal and numerical descriptor label group (Super Low 4%ABV: M = 154.59ml, B = 20.68, 95%CI = 4.32, 37.04, p-value = 0.014) drank significantly greater amounts than those randomised to the verbal descriptor label group (Super Low: M = 125.65ml). This bar laboratory study estimated that a greater quantity of 'lower' strength wine was consumed when the label included a numerical strength descriptor compared with a verbal only strength descriptor. [Abstract copyright: This article is protected by copyright. All rights reserved.

Do alcohol product labels stating lower strength verbal description, percentage alcohol‐by‐volume, or their combination affect wine consumption? A bar laboratory adaptive randomised controlled trial

Background and Aims A previous research study concluded that wine and beer labelled as lower in strength increase consumption compared with the same drinks labelled as regular strength. The label included both a verbal and numerical descriptor of strength. The present study aimed to estimate the effect of each of these label components. Design Adaptive, parallel group randomised controlled trial, comprising an internal pilot sample (n1 = 90) and a confirmatory sample (n2 = 57). Setting University bar laboratory in London, United Kingdom (UK). Participants A total of 147 weekly wine drinkers were sampled from a nationally representative English panel. Intervention Participants were randomised to one of three groups to taste test wine in a bar‐laboratory, varying only in the label displayed: (i) verbal descriptor only (Super Low); (ii) numerical descriptor only (4% alcohol by volume (ABV)); and (iii) verbal descriptor and numerical descriptor combined (Super Low 4%ABV) (each group n = 49). Measurements The primary outcome was total volume (ml) of wine consumed. Findings Participants randomised to the numerical descriptor label group (4%ABV: M = 155.12 ml, B = 20.30; 95% CI = 3.92, 36.69; P value = 0.016) and combined verbal and numerical descriptor label group (Super Low 4%ABV: M = 154.59 ml, B = 20.68; 95% CI = 4.32, 37.04; P value = 0.014) drank significantly greater amounts than those randomised to the verbal descriptor label group (Super Low: M = 125.65 ml). Conclusions This bar laboratory study estimated that a greater quantity of ‘lower’ strength wine was consumed when the label included a numerical strength descriptor compared with a verbal only strength descriptor