Friedberg-Lee symmetry and tri-bimaximal neutrino mixing in the inverse seesaw mechanism

The inverse seesaw mechanism with three pairs of gauge-singlet neutrinos offers a natural interpretation of the tiny masses of three active neutrinos at the TeV scale. We combine this picture with the newly-proposed Friedberg-Lee (FL) symmetry in order to understand the observed pattern of neutrino mixing. We show that the FL symmetry requires only two pairs of the gauge-singlet neutrinos to be massive, implying that one active neutrino must be massless. We propose a phenomenological ansatz with broken FL symmetry and exact \mu-\tau symmetry in the gauge-singlet neutrino sector and obtain the tri-bimaximal neutrino mixing pattern by means of the inverse seesaw relation. We demonstrate that non-unitary corrections to this result are possible to reach the percent level and a soft breaking of \mu-\tau symmetry can give rise to CP violation in such a TeV-scale seesaw scenario.Comment: RevTeX 16 pages. Minor changes. Accepted for publication in Phys. Rev.

Scalar Field Cosmology II: Superfluidity, Quantum Turbulence, and Inflation

We generalize the big-bang model in a previous paper by extending the real vacuum scalar field to a complex vacuum scalar field, within the FLRW framework. The phase dynamics of the scalar field, which makes the universe a superfluid, is described in terms of a density of quantized vortex lines, and a tangle of vortex lines gives rise to quantum turbulence. We propose that all the matter in the universe was created in the turbulence, through reconnection of vortex lines, a process necessary for the maintenance of the vortex tangle. The vortex tangle grows and decays, and its lifetime is the era of inflation. These ideas are implemented in a set of closed cosmological equations that describe the cosmic expansion driven by the scalar field on the one hand, and the vortex-matter dynamics on the other. We show how these two aspects decouple from each other, due to a vast difference in energy scales. The model is not valid beyond the inflation era, but the universe remains a superfluid afterwards. This gives rise to observable effects in the present universe, including dark matter, galactic voids, non-thermal filaments, and cosmic jets.Comment: 29 pages, 7 figures, published versio

LABORATORY CHARACTERIZATION OF BITUMINOUS MIXTURES FOR PAVEMENTS

Ph.DDOCTOR OF PHILOSOPH

Development of an engine control module and dashboard display based on electric vehicle system

This project involves the design and building of an electric vehicle based on the Honda S2000 convertible. Along the design process, numerous changes have been made to incorporate new features such as conversion to a 4 seater sedan, inclusion of battery packs, wireless charging features and such. With the modifications involved, the original S2000 on board systems have to be revised and changed as accordingly. One of the revisions involved the conversion from an ignition engine to an electric motor. Of which the ignition engine system had an Engine Control Module (ECM); the ECM controls fuel emission procedures, air intake and other processes. With the implementation of an electric motor, such systems will removed and changes made to integrate the new Electric Vehicle (EV) systems. One of the systems modified to integrate the new systems was the instrument panel as taken from the original S2000. The various indicators will be adapted to the requirements for the EV systems; indicators and relevant displays will indicate the various signals for the system. Modern vehicles have a number of different on-board systems to maintain the various running functions of the EV. To have an overall system to tie up the on-board controllers the Raspberry-Pi computer will be used along with a touchscreen display for the EV.Bachelor of Engineerin

Scalar field cosmology : I. asymptotic freedom and the initial-value problem

The purpose of this work is to use a renormalized quantum scalar field to investigate very early cosmology, in the Planck era immediately following the big bang. Renormalization effects make the field potential dependent on length scale, and are important during the big bang era. We use the asymptotically free Halpern-Huang scalar field, which is derived from renormalization-group analysis, and solve Einsteins equation with Robertson-Walker metric as an initial-value problem. The main prediction is that the Hubble parameter follows a power law: H ≡ a/a ∼ t -p, and the universe expands at an accelerated rate: a ∼ expt 1-p. This gives dark energy, with an equivalent cosmological constant that decays in time like t -2p, which avoids the fine-tuning problem. The power law predicts a simple relation for the galactic redshift. Comparison with data leads to the speculation that the universe experienced a crossover transition, which was completed about seven billion years ago

Field implementation of warm mix asphalt using different binders

The objective of this paper is to present the results and observations obtained from the laboratory tests and field implementations of warm mix asphalt (WMA) formulated using different binders. Laboratory tests were performed using the WMA mixes and the conventional hot mix asphalt (HMA) as a reference prior to implementation at the sites. The WMA mixes were laid at 2 different locations (i.e. along a major road and in a road tunnel) in Singapore. The performance of the WMA mixes was assessed by conducting temperature measurements during laying operations and monitored through visual inspections and by measuring riding quality of the road in terms of International Roughness Index. From the laboratory results, it was observed that the WMA mixes provided similar results as compared with the conventional HMA. From the field implementations, it was noted that the WMA mixes produced similar workability as compared to HMA. In addition, it was observed that WMA can be compacted at the lower temperature of approximately 110 ˚C

Laboratory wheel tracking apparatus for bituminous pavement studies

Journal of Testing and Evaluation206470-474JTEV

A Comprehensive Comparative Study on

Term weighting scheme, which has been used to convert the documents as vectors in the term space, is a vital step in automatic text categorization. In this paper, we conducted comprehensive experiments to compare various term weighting schemes with SVM on two widely-used benchmark data sets. We also presented a new term weighting scheme tf.rf to improve the term's discriminating power. The controlled experimental results showed that this newly proposed tf.rf scheme is significantly better than other widely-used term weighting schemes. Compared with schemes related with tf factor alone, the idf factor does not improve or even decrease the term's discriminating power for text categorization