Generation of internal stress and its effects

Internal stresses may be generated continually in many polycrystalline materials. Their existence is manifested by changes in crystal defect concentration and arrangement, by surface observations, by macroscopic shape changes and particularly by alteration of mechanical properties when external stresses are simultaneously imposed

Chiral Reductions in the Salam-Sezgin Model

Reductions from six to four spacetime dimensions are considered for a class of supergravity models based on the six-dimensional Salam-Sezgin model, which is a chiral theory with a gauged U(1) R-symmetry and a positive scalar-field potential. Reduction on a sphere and monopole background of such models naturally yields four-dimensional theories without a cosmological constant. The question of chirality preservation in such a reduction has been a topic of debate. In this article, it is shown that the possibilities of dimensional reduction bifurcate into two separate consistent dimensional-reduction schemes. One of these retains the massless SU(2) vector gauge triplet arising from the sphere's isometries, but it produces a non-chiral four-dimensional theory. The other consistent scheme sets to zero the SU(2) gauge fields, but retains the gauged U(1) from six dimensions and preserves chirality although the U(1) is spontaneously broken. Extensions of the Salam-Sezgin model to include larger gauge symmetries produce genuinely chiral models with unbroken gauge symmetries.Comment: 37 page

FOULING DURING THE USE OF ‘FRESH’ WATER AS COOLANT- THE DEVELOPMENT OF A ‘USER GUIDE’

IHS ESDU recently published its latest ‘User Guide’ to fouling in heat exchange systems, for systems with fresh water as the coolant. ESDU 07006 [1] is the third in a group, following the development of the Crude Oil Fouling User Guide [2] issued in 2000 and the Seawater Fouling User Guide [3] issued in 2004. ESDU 07006 was developed by IHS ESDU over a period of five years under the guidance of the Oil Industry Fouling Working Party, a collaborative team of oil refiners, heat transfer equipment and services suppliers and Universities. It provides designers and operators of cooling water facilities with a practical source of guidance on the occurrence, the mechanisms and the mitigation of fresh water fouling in these systems. IHS ESDU’s Oil Industry Fouling Working Party was formed in recognition of the huge economic and environmental importance of heat exchanger fouling and the potential benefits that can accrue from better understanding of mitigation strategies. Work is now underway on reboiler and FCCU fouling. The development of the User Guide ESDU 07006 is discussed in this paper and its technical content is summarized

Electronic band structure, Fermi surface, and elastic properties of new 4.2K superconductor SrPtAs from first-principles calculations

The hexagonal phase SrPtAs (s.g. P6/mmm; #194) with a honeycomb lattice structure very recently was declared as a new low-temperature (TC ~ 4.2K) superconductor. Here by means of first-principles calculations the optimized structural parameters, electronic bands, Fermi surface, total and partial densities of states, inter-atomic bonding picture, independent elastic constants, bulk and shear moduli for SrPtAs were obtained for the first time and analyzed in comparison with the related layered superconductor SrPt2As2.Comment: 8 pages, 4 figure

Trekstock RENEW: evaluation of a 12-week exercise referral programme for young adult cancer survivors delivered by a cancer charity.

PURPOSE: To evaluate the uptake and effect of RENEW, a 12-week exercise referral programme for young adult cancer survivors delivered by Trekstock, a UK-based cancer charity. METHODS: The RENEW programme provides one-to-one individually tailored support from a level-4 cancer-rehabilitation-qualified gym instructor, free gym membership and access to information resources online. Objective and self-report data on cardiorespiratory function, strength, body composition, fatigue, sleep quality and general health-related quality of life (HRQoL) was collected from participants before the programme (week 0), immediately after (week 12) and 1 month later (week 16). RESULTS: Forty-eight young adults (83% female; mean age, 29 years) with a history of cancer took part within the 12-week programme and completed the evaluation measures. Physical activity (PA) levels significantly increased following the programme and remained raised at follow-up. Improvements in physical function were significant: peak expiratory flow (mean change, 30.96, p = 0.003), sit-and-reach test (mean change, 6.55 ± 4.54, p < 0.0001), and 6-mine-walk test (mean change, 0.12 ± 0.04, p < 0.0001). No significant changes in BMI, weight or muscle mass were observed. Improvements in fatigue, sleep and HRQoL were observed across the programme and at follow-up (mean change, weeks 0-16; 8.04 ± 1.49 p < 0.01; 1.05 ± 0.49 p < 0.05; and - 0.9 ± 0.46 p = 0.051, respectively). Changes in self-efficacy to exercise and motivations to exercise were not observed at 12 weeks or at follow-up. CONCLUSIONS: Results suggest that the RENEW exercise referral programme has a positive impact upon some domains of physical function and well-being among young adult cancer survivors. IMPLICATION FOR CANCER SURVIVORS: Exercise referral programmes delivered by charity organisations are one means by which PA behaviour change support may be widely disseminated to young adult cancer survivors. Health professionals and charitable bodies specialising in the care of young adults with cancer should look to address factors which prevent engagement and uptake of 'real-world' PA interventions such as the RENEW programme

The Use of Unregulated Staff: Time for Regulation?

Internationally, shortages in the nursing workforce, escalating patient demands, and financial constraints within the health system have led to the growth of unlicensed nursing support workers. Recently, in relation to the largest publicly funded health system (National Health Service), it was reported that extensive substitution of registered nurses with unskilled nursing support workers resulted in inadequate patient care, increased morbidity and mortality rates, and negative nurse outcomes. We argue that it is timely to consider regulation of nursing support workers with their role and scope of practice clearly defined. Further, the addition of these workers in a complementary model of care (rather than substitutive model) should also be explored in future research, in terms of impact on patient and nurse outcomes. © The Author(s) 2014 Reprints and permissions:]br]sagepub.co.uk/journalsPermissions.nav

Retrofitting Crude Oil Refinery Heat Exchanger Networks to Minimise Fouling While Maximising Heat Recovery

The use of fouling factors in heat exchanger design and the lack of appreciation of fouling in traditional pinch approach has often resulted badly designed crude preheat networks that are expensive to maintain. The development of thermal and pressure drop models for crude oil fouling has allowed its effects to be quantified, so that techno-economic analyses can be performed and various design options compared. Application of these fouling models is carried out on two levels: on the assessment of adding extra area to individual exchangers, and the design of a complete network using the Modified Temperature Field Plot. Application to a refinery case study showed that both at the exchanger and network levels, designing for maximum heat recovery using traditional pinch approach results in the least efficient heat recovery over a time period when fouling occurs

Breaking quantum linearity: constraints from human perception and cosmological implications

Resolving the tension between quantum superpositions and the uniqueness of the classical world is a major open problem. One possibility, which is extensively explored both theoretically and experimentally, is that quantum linearity breaks above a given scale. Theoretically, this possibility is predicted by collapse models. They provide quantitative information on where violations of the superposition principle become manifest. Here we show that the lower bound on the collapse parameter lambda, coming from the analysis of the human visual process, is ~ 7 +/- 2 orders of magnitude stronger than the original bound, in agreement with more recent analysis. This implies that the collapse becomes effective with systems containing ~ 10^4 - 10^5 nucleons, and thus falls within the range of testability with present-day technology. We also compare the spectrum of the collapsing field with those of known cosmological fields, showing that a typical cosmological random field can yield an efficient wave function collapse.Comment: 13 pages, LaTeX, 3 figure