The signatures of large-scale patterns of atmospheric variability in Antarctic surface temperatures

We investigate the impact that the four principal large-scale patterns of Southern Hemisphere (SH) atmospheric circulation variability have on Antarctic surface air temperature (SAT): (1) the southern baroclinic annular mode (BAM), which is associated with variations in extratropical storm amplitude; (2) the Southern Annular Mode (SAM), associated with latitudinal shifts in the midlatitude jet; and (3) the two Pacific-South American patterns (PSA1 and PSA2), which are characterized by wave trains originating in the tropical Pacific that extend across the SH extratropics. A key aspect is the use of 35 years of daily observations and reanalysis data, which affords a sufficiently large sample size to assess the signatures of the circulation patterns in both the mean and variability of daily mean SAT anomalies. The BAM exerts the weakest influence on Antarctic SAT, albeit it is still important over select regions. Consistent with previous studies, the SAM is shown to influence SAT across most of the continent throughout the year. The PSA1 also affects SAT across almost all of Antarctica. Regionally, both PSA patterns can exert a greater impact on SAT than the SAM but also have a significantly weaker influence during summer, reflecting the seasonality of the SH response to El Niño–Southern Oscillation. The SAM and PSA patterns have distinct signatures in daily SAT variance that are physically consistent with their signatures in extratropical dynamic variability. The broad-scale climate linkages identified here provide benchmarks for interpreting the Antarctic climate response to future changes in tropical sea surface temperatures, ozone recovery, and greenhouse gas increases

Dual Thermographic Monitoring of Ti-6Al-4V Cylinders During Direct Laser Deposition

Understanding the thermal phenomena associated with Direct Laser Deposition (DLD) is necessary to begin manipulating fabricated part properties. In this study, a thermally monitored Laser Engineered Net Shaping (LENS) system is used with time-invariant (uncontrolled) build parameters to construct Ti-6Al-4V cylinders with two different build paths. Both paths utilize a circular contour with serpentine hatch fill; however, successive layer patterns are varied and the effects compared between 90° and 120° angular pattern shifts. During fabrication, the part’s thermal history and melt pool temperature are recorded via an in-chamber infrared (IR) camera and a dual-wavelength (DW) pyrometer, respectively. These tools are used for non-destructive thermographic inspection (NTI) of the part to ensure target quality and/or microstructure. A unique calibration method for the IR camera utilizing the DW pyrometer data is presented and a calibration correction factor was utilized for high temperature ranges. The melt pool was found to be 40-50% superheated reaching temperatures up to 2500 ºC at times. Temperature characteristics of two different layers were compared for different hatching patters, and the results show that for a given point in time, maximum temperatures can vary based on laser raster. Temperature gradients varied and peaked at about 1000 ºC/mm along the diameter of the small rods. This can lead to anisotropy in microstructural and mechanical properties allowing for unique property growth per build path. Cooling rates within the melt pool appear to increase as maximum melt pool temperature increases, for instance, from 16,000 ºC/s – 41,000 ºC/s.Mechanical Engineerin

The signature of Southern Hemisphere atmospheric circulation patterns in Antarctic precipitation

We provide the first comprehensive analysis of the relationships between large-scale patterns of Southern Hemisphere climate variability and the detailed structure of Antarctic precipitation. We examine linkages between the high spatial resolution precipitation from a regional atmospheric model and four modes of large-scale Southern Hemisphere climate variability: the southern baroclinic annular mode (BAM), the southern annular mode (SAM), and the two Pacific-South American (PSA) teleconnection patterns. Variations in all four modes influence the spatial patterns of precipitation over Antarctica, consistent with their signatures in high-latitude meridional moisture fluxes. They impact not only the mean but also the incidence of extreme precipitation events. Current coupled-climate models are able to reproduce all four patterns of atmospheric variability, but struggle to correctly replicate their regional impacts on Antarctic climate. Thus, linking these patterns directly to Antarctic precipitation variability may allow a better estimate of future changes in precipitation than using model output alone

The Muonium Atom as a Probe of Physics beyond the Standard Model

The observed interactions between particles are not fully explained in the successful theoretical description of the standard model to date. Due to the close confinement of the bound state muonium ($M = \mu^+ e^-$) can be used as an ideal probe of quantum electrodynamics and weak interaction and also for a search for additional interactions between leptons. Of special interest is the lepton number violating process of sponteanous conversion of muonium to antimuonium.Comment: 15 pages,6 figure

Living for the weekend: youth identities in northeast England

Consumption and consumerism are now accepted as key contexts for the construction of youth identities in de-industrialized Britain. This article uses empirical evidence from interviews with young people to suggest that claims of `new community' are overstated, traditional forms of friendship are receding, and increasingly atomized and instrumental youth identities are now being culturally constituted and reproduced by the pressures and anxieties created by enforced adaptation to consumer capitalism. Analysis of the data opens up the possibility of a critical rather than a celebratory exploration of the wider theoretical implications of this process

An investigation of a criterion- referenced test using G-theory, and factor and cluster analyses

There has been relatively little research on analytical procedures for examin ing the dependability and validity of criterion-referenced tests especially when compared to similar investigations for norm-referenced ESL or EFL tests. This study used three analytical procedures, namely, G-theory, factor and cluster analyses, to investigate the dependability and validity of a criterion-referenced test developed at the University of California, Los Angeles in 1989. Dependability estimates showed that test scores are not equally depend able for all placement groups and are rather undependable for two out of the four placement groups. Factor analysis of test scores for the placement groups showed that though two-factor solutions were the best solutions for the different groups, there were differences in the way the subtests loaded in the different groups, with progressively fewer subtests loading on the second factor as ability increased. This finding led to the extension study with cluster analysis which showed that a number of students might have been differently placed if subtest scores were used to place them.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68766/2/10.1177_026553229200900104.pd

The effect of spontaneous collapses on neutrino oscillations

We compute the effect of collapse models on neutrino oscillations. The effect of the collapse is to modify the evolution of the `spatial' part of the wave function, which indirectly amounts to a change on the flavor components. In many respects, this phenomenon is similar to neutrino propagation through matter. For the analysis we use the mass proportional CSL model, and perform the calculation to second order perturbation theory. As we will show, the CSL prediction is very small - mainly due to the very small mass of neutrinos - and practically undetectable.Comment: 24 pages, RevTeX. Updated versio

Predicting the cost of the consequences of a large nuclear accident in the UK

Nuclear accidents have the potential to lead to significant off-site effects that require actions to minimise the radiological impacts on people. Such countermeasures may include sheltering, evacuation, restrictions on the sale of locally-grown food, and long-term relocation of the population amongst others. Countries with nuclear facilities draw up emergency preparedness plans, and put in place such provisions as distributing instructions and iodine prophylaxis to the local population. Their plans are applied in simulated exercises on a regular basis. The costs associated with emergency preparedness and the safety provisions to reduce the likelihood of an accident, and/or mitigate the consequences, are justified on the basis of the health risks and accident costs averted. There is, of course, only limited actual experience to indicate the likely costs so that much of the costing of accidents is based on calculations. This paper reviews the methodologies used, in particular the approach that has been developed in the UK, to appraise the costs of a hypothetical nuclear accident. Results of analysing a hypothetical nuclear accident at a fictitious reactor site within the United Kingdom are discussed in relation to the accidents at Three Mile Island 2, Chernobyl and Fukushima Dai-ichi