Model Independent Expansion History from Supernovae: Cosmology versus Systematics

We examine the Pantheon supernovae distance data compilation in a model independent analysis to test the validity of cosmic history reconstructions beyond the concordance $\Lambda$CDM cosmology. Strong deviations are allowed by the data at $z\gtrsim1$ in the reconstructed Hubble parameter, $Om$ diagnostic, and dark energy equation of state. We explore three interpretations: 1) possibility of the true cosmology being far from $\Lambda$CDM, 2) supernovae property evolution, and 3) survey selection effects. The strong (and theoretically problematic) deviations at $z\gtrsim1$ vanish and good consistency with $\Lambda$CDM is found with a simple Malmquist-like linear correction. The adjusted data is robust against the model independent iterative smoothing reconstruction. However, we caution that while by eye the original deviation from $\Lambda$CDM is striking, $\chi^2$ tests do not show the extra linear correction parameter is statistically significant, and a model-independent Gaussian Process regression does not find significant evidence for the need for correction at high-redshifts.Comment: 9 pages, 6 figures, accepted for publication in MNRA

KATRIN Sensitivity to Sterile Neutrino Mass in the Shadow of Lightest Neutrino Mass

The presence of light sterile neutrinos would strongly modify the energy spectrum of the Tritium \beta-electrons. We perform an analysis of the KATRIN experiment's sensitivity by scanning almost all the allowed region of neutrino mass-squared difference and mixing angles of the 3+1 scenario. We consider the effect of the unknown absolute mass scale of active neutrinos on the sensitivity of KATRIN to the sterile neutrino mass. We show that after 3 years of data-taking, the KATRIN experiment can be sensitive to mixing angles as small as sin^2 (2\theta_s) ~ 10^-2. Particularly we show that for small mixing angles, sin^2 (2\theta_s) < 0.1, the KATRIN experiment can gives the strongest limit on active-sterile mass-squared difference.Comment: 4 pages, 2 figures, matches the published versio

A new null diagnostic customized for reconstructing the properties of dark energy from BAO data

Baryon Acoustic Oscillations (BAO) provide an important standard ruler which can be used to probe the recent expansion history of our universe. We show how a simple extension of the Om diagnostic, which we call Om3, can combine standard ruler information from BAO with standard candle information from type Ia supernovae (SNIa) to yield a powerful novel null diagnostic of the cosmological constant hypothesis. A unique feature of Om3 is that it requires minimal cosmological assumptions since its determination does not rely upon prior knowledge of either the current value of the matter density and the Hubble constant, or the distance to the last scattering surface. Observational uncertainties in these quantities therefore do not affect the reconstruction of Om3. We reconstruct Om3 using the Union 2.1 SNIa data set and BAO data from SDSS, WiggleZ and 6dFGS. Our results are consistent with dark energy being the cosmological constant. We show how Om and Om3 can be used to obtain accurate model independent constraints on the properties of dark energy from future data sets such as BigBOSS.Comment: 9 pages, 4 figures, discussions extended, results unchanged, matches the final version published in PR

An intelligent alternating current-optimal power flow for reduction of pollutant gases with incorporation of variable generation resources

Frequent escalations in fuel costs, environmental concerns, and the depletion of non-renewable fuel reserves have driven the power industry to significant utilisation of renewable energy resources. These resources cannot satisfy the entire system load demand because of the intermittent nature of variable generation resources (VGRs) such as wind and solar. Therefore, there is a need to optimally schedule the generating units (thermal and VGRs) to reduce the amount of fuel used and the level of emissions produced. In this study, an AC-power flow in conjunction with combined economic and environmental dispatch approach through the implementation of a modified constricted coefficient particle swarm optimisation was used to minimise the fuel cost and the level of emission gases produced. The approach was applied to the Institute of Electric and Electronic Engineers 30 bus test system through three different load conditions: base-load, increase-load and critical-load. The results showed the practicality of the proposed approach for the simultaneous reduction of the total generation cost and emission levels on a large electrical power grid while maintaining all the physical and operational constraints of the system

High-skilled female immigrants: career strategies and experiences

© 2018, Emerald Publishing Limited. Purpose: The purpose of this paper is to uncover career-related issues that high-skilled female immigrants face and their strategies for rebuilding their careers upon migration for a diverse range of reasons including following a spouse, furthering education and self-initiated expatriation. Design/methodology/approach: Using grounded theory to explore this topic, the authors performed 14 in-depth interviews with female immigrants that fit pre-determined inclusion criteria for high-skilled (e.g. educated, gainfully and professionally employed). The study context of immigration is the USA, and the authors performed interviews with high-skilled immigrants from Turkey – an underrepresented nation in the US migrant population. Findings: Content analysis of in-depth interviews revealed five primary theoretical themes that captured the career experiences of these individuals: non-linear career entry, career orientation, strong commitment and will to succeed, socialization patterns at work and support network. Integrating these findings with theories on adult learning, the authors developed an experiential learning model of career reconstruction among high-skilled immigrants. Originality/value: This study contributes to the global mobility literature by developing an experiential learning theory of careers and taking a gendered perspective to the career experiences of high-skilled female immigrants. It answers the questions: what are the individual and situation factors associated with career success among high-skilled female immigrants? and what is the process that high-skilled immigrants go through to rebuild their careers

Studi Perbandingan Kinerja Sistem Struktur Setback berdasarkan Metode ATC 40, FEMA 356 dan SNI 1726:2012

The aim of this study was to compare the performance level of the setback structure system and the non-setback structural system using the ATC-40, FEMA 356 and SNI 1726-2012 methods. The non-setback structure have the shortest span of 15 m, the longest span of 20 m and the level of each floor was 3.5 m but the setback structure have setback system on the longest span of 10 m at the 5th and 6th floor level. The results showed that the performance level based on all methods of the sectback structure system is at the immediate occupancy level while the non-setback structure system, based on SNI 1726-2012, the performance level is immediate occupancy for the longest span and the shortest span is damage control. On the other hand, based on the ATC-40 and FEMA 356 methods, the performance level of the non-setback structure is at the immediate occupancy level. Drift on non-setback buildings based on the SNI 1726-2012 method is 0.011, based on the ATC-40 method is 0.007, and based on FEMA 356 is 0.005. Drift on the setback building based on the SNI 1726-2012 method is 0.010, based on the ATC-40 method is 0.006, and based on FEMA 356 is 0.004

Dynamic response of phenolic resin and its carbon-nanotube composites to shock wave loading

We investigate with nonreactive molecular dynamics simulations the dynamic response of phenolic resin and its carbon-nanotube (CNT) composites to shock wave compression. For phenolic resin, our simulations yield shock states in agreement with experiments on similar polymers except the “phase change” observed in experiments, indicating that such phase change is chemical in nature. The elastic–plastic transition is characterized by shear stress relaxation and atomic-level slip, and phenolic resin shows strong strain hardening. Shock loading of the CNT-resin composites is applied parallel or perpendicular to the CNT axis, and the composites demonstrate anisotropy in wave propagation, yield and CNT deformation. The CNTs induce stress concentrations in the composites and may increase the yield strength. Our simulations suggest that the bulk shock response of the composites depends on the volume fraction, length ratio, impact cross-section, and geometry of the CNT components; the short CNTs in current simulations have insignificant effect on the bulk response of resin polymer