High scale perturbative gauge coupling in R-parity conserving SUSY SO(10) with longer proton lifetime

It is well known that in single step breaking of R-parity conserving SUSY SO(10) that needs the Higgs representations $126+\bar 126$ the GUT-gauge coupling violates the perturbative constraint at mass scales few times larger than the GUT scale. Therefore, if the SO(10) gauge coupling is to remain perturbative up the Planck scale(=2x10^{18} GeV), the scale $M_U$ of GUT symmetry breaking is to be bounded from below. The bound depends upon specific Higgs representations used for SO(10) symmetry breaking but, as we find, can not be lower than $1.5x10^{17}$ GeV. In order to obtain such high unification scale we propose a two-step SO(10) breaking through $SU(2)_LXSU(2)_RXU(1)_{B-L}XSU(3)_C(g_{2L} \neq g_{2R})$ intermediate gauge symmetry. We estimate potential threshold and gravitational corrections to the running of gauge couplings and show that they can make the picture of perturbative GUT- gauge coupling running consistent at least up to the Planck scale. We also show that when $SO(10) \to G_{2213}$ by $210 + 54$, gravitational corrections alone with negligible threshold effects may guarantee such perturbative gauge coupling. The lifetime of the proton is found to increase by nearly 6 orders over the current experimental limit for $p \to e^+\pi^0$. For the proton decay mediated by dim.5 operator a wide range of lifetimes is possible extending from the current experimental limit up to values 2-3 orders longer.Comment: 11 pages epjc LaTex as per specifications of European Physical Journal

Vanishing corrections on the intermediate scale and implications for unification of forces

In two-step breaking of a class of grand unified theories including SO(10),we prove a theorem showing that the scale $M_I$ where the Pati-Salam gauge symmetry with parity breaks down to the standard gauge group,has vanishing corrections due to all sources emerging from higher scales $\mu >M_I$ such as the one-loop and all higher loop effects,the GUT-threshold,gravitational smearing,and string threshold effects. Implications of such a scale for the unification of gauge couplings with small Majorana neutrino masses are discussed.In string inspired SO(10) we show that $M_I \simeq 5\times 10^{12}$,needed for neutrino masses,with the GUT scale $M_U \simeq M_{str}$ can be realized provided certain particle states in the predicted spectum are light.Comment: 21 pages, Late

Precision and uncertainties in mass scale predictions in SUSY SO(10) with SU(2)_L x SU(2)_R x U(1)_{B-L} x SU(3)_C intermediate breaking

In a class of SUSY SO(10) with $SU(2)_L x SU(2)_R x U(1)_{B-L} x SU(3)_C$ $(g_{2L}\neq g_{2R})$ intermediate gauge symmetry, we observe that the prediction on the unification mass $(M_U)$ is unaffected by Planck-scale-induced gravitational and intermediate-scale-threshold effects, although the intermediate scale $(M_I)$ itself is subject to such corrections. In particular, without invoking the presence of additional lighter scalar degrees of freedom but including plausible and reasonable threshold effects, we find that interesting solutions for neutrino physics corresponding to $M_I\simeq 10^{10}-10^{13}$ GeV and $M_U\simeq (5-6) x 10^{17}$ GeV are permitted in the minimal models. Possibilities of low-mass right-handed gauge bosons corresponding to $M_I\simeq 1-10$ TeV consistent with the CERN-LEP data are pointed out in a number of models when threshold effects are included using effective mass parameters.Comment: 12 pages including 7 tables (Typos corrected as per the published version

Genetic and antigenic characterisation of serotype A FMD viruses from East Africa to select new vaccine strains

Vaccine strain selection for emerging foot-and-mouth disease virus (FMDV) outbreaks in enzootic countries can be addressed through antigenic and genetic characterisation of recently circulating viruses. A total of 56 serotype A FMDVs isolated between 1998 and 2012, from Central, East and North African countries were characterised antigenically by virus neutralisation test using antisera to three existing and four candidate vaccine strains and, genetically by characterising the full capsid sequence data. A Bayesian analysis of the capsid sequence data revealed the viruses to be of either African or Asian topotypes with subdivision of the African topotype viruses into four genotypes (Genotypes I, II, IV and VII). The existing vaccine strains were found to be least cross-reactive (good matches observed for only 5.4–46.4% of the sampled viruses). Three bovine antisera, raised against A-EA-2007, A-EA-1981 and A-EA-1984 viruses, exhibited broad cross-neutralisation, towards more than 85% of the circulating viruses. Of the three vaccines, A-EA-2007 was the best showing more than 90% in-vitro cross-protection, as well as being the most recent amongst the vaccine strains used in this study. It therefore appears antigenically suitable as a vaccine strain to be used in the region in FMD control programmes

Feasibility of using ultrasonic technique to measure the blast furnace lining thickness

Blast furnace process has been the most effective way to produce iron for over 200 years.Throughout the years, large efforts have been put on finding ways to increase the productivity and extend the campaign length. The condition of the refractory lining of a blast furnace plays a very important role to determine its campaign length. Many methods have been employed to measure blast furnace lining thickness including radioisotopes, thermal measurement and core-drilling. Temperature measurement is among the most widely used method for on-line monitoring the profile of the blast furnace inner surface, which is based on numerically solving inverse problem using heat transfer models and readings from thermocouple. Optimization methods are applied to obtain the boundary of the domain iteratively, and hence the computation is very expensive and calculation cannot be very accurate. This paper presents the feasibility of using non-invasive ultrasonic technique in bistatic mode to measure the profile of the refractory liner of the hearth region of blast furnace

Non-linear ultrasonic technique to assess fatigue damage in structural steel

A non-linear ultrasonic technique has been used to assess the fatigue damage in low carbon structural steel. The percentage of total harmonic distortion, which is the ratio of the amplitude of 2nd harmonic and the fundamental, has been introduced as the measurement parameter in this paper. It has also been observed that before crack initiation the 2nd harmonic amplitude is comparable to the fundamental. The results have been analysed in light of the dislocation theory for harmonic generation during material degradation