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The objective of present study is to develop a time series model for handling the non-linear trend process using a spline function. Spline function is a piecewise polynomial segment concerning the time component. The main advantage of spline function is the approximation, non linear time trend, but linear time trend between the consecutive join points. A unit root hypothesis is projected to test the non stationarity due to presence of unit root in the proposed model. In the autoregressive model with linear trend, the time trend vanishes under the unit root case. However, when non-linear trend is present and approximated by the linear spline function, through the trend component is absent under the unit root case, but the intercept term makes a shift with r knots. For decision making under the Bayesian perspective, the posterior odds ratio is used for hypothesis testing problems. We have derived the posterior probability for the assumed hypotheses under appropriate prior information. A simulation study and an empirical application are presented to examine the performance of theoretical outcomes.

We present results from timing and spectral analysis of the HMXB X-ray pulsar IGR J19294+1816 observed using \asr during its recent Type-I outburst in October, 2019. AstroSat observations sampled the outburst at the decline phase right after the outburst peak. We carried out timing analysis on the light curves obtained using the Large Area X-ray Proportional Counter (LAXPC) instrument on board AstroSat and measured a spin period of 12.485065$\pm$0.000015 s. The peak in the power density spectrum (PDS) corresponding to the spin period of 12.48 s also shows a broadened base. We also detected a Quasi Periodic Oscillation (QPO) feature at 0.032$\pm$0.002 Hz with an RMS fractional amplitude of $\sim$18% in the PDS. We further carried out a joint spectral analysis using both the Soft X-ray Telescope (SXT) and the LAXPC instruments and detected a Cyclotron Resonant Scattering Feature (CRSF) at 42.7$\pm$0.9 keV and an Fe emission line at 6.4$\pm$0.1 keV. IGR J19294+1816, being an intermediate spin pulsar, has exhibited a plethora of spectral and timing features during its most recent 2019 outburst, adding it to the list of transients that exhibit both a QPO as well as a CRSF.

OJ 287 is a well-studied binary black hole system, that occasionally exhibits bright X-ray and optical flares. Here we present a detailed spectral study of its second brightest X-ray flare observed during 2019-2020 using archival Swift and NuSTAR observations along with ToO observations from AstroSat. The entire flaring period is divided into three states, defined as low, intermediate, and high states. The variation of hardness ratio (HR) with 0.3-10.0 keV integrated flux suggests a \enquote{softer-when-brighter} behavior, as also previously reported based on flux-index variations. Simultaneous high state X-ray spectra obtained using Swift, NuSTAR and AstroSat are very steep with a power-law index $>$2. A significant spectral change is observed in AstroSat-SXT and LAXPC spectrum which is consistent with Swift-XRT and NuSTAR spectrum. Together, optical-UV and X-ray spectrum during the high flux state, suggesting the emergence of a new high BL Lacertae (HBL) component. We have modeled the synchrotron peak with publicly available code named GAMERA for low, intermediate, and high flux state. Our modeling suggests the need of high magnetic field to explain the high state under the leptonic scenarios. Increase in the magnetic field value inside the jet could be linked to the increase in accretion rate as expected in the BH-disk impact scenario. The color-magnitude diagram reveals a \enquote{bluer-when-brighter} spectral energy distribution chromatism during the flaring period. Different chromatism or no chromatism at various occasions suggests a complex origin of optical emission, which is believed to be produced by disc impact or through synchrotron emission in the jet.

Open pit excavation induces rock mass damage as a result of stress release and blasting. The damage reduces the rock mass strength and stiffness. The strength reduction is typically quantified by the Hoek–Brown disturbance factor (D). Limitations of this approach are outlined in the paper. It is proposed that degradation of rock mass strength and stiffness results from damage followed by disturbance. Damage is caused by fracturing of intact rock (e.g. failure of rock bridges) that results from small strains (less than approximately 2 percent) and only increases porosity slightly. Disturbance is caused by rearrangement of intact rock blocks that results from large strains (perhaps 10 percent) and usually produces a large increase in porosity. The strength degradation produced by damage is quantified by the peak and post-peak strengths, and the strength degradation produced by disturbance is quantified by the residual strength. When using numerical models to study the progressive failure of rock masses, estimates of the damage characteristics are required. In many of these models, the Hoek–Brown failure criterion is treated as a yield criterion and the analysis is carried out using plasticity theory. The work described here is aimed at defining the appropriate evolution of rock mass strength as applied to slope stability studies. We do this by studying the stress-strain response of 3D bonded block models with low-porosity structures that range from blocky to disintegrated and a highporosity structure that mimics rockfill. The synthetic peak and post-peak strength envelopes are compared with Hoek–Brown strength envelopes with D factors of zero and one. The comparisons support the following conclusions. Peak and post-peak strength are similar for lower quality (Geological Strength Index less than approximately 40) rock masses. Hoek–Brown strengths for D = 1 are lower than post-peak strengths, with the difference being more pronounced for lower quality rock masses. For low quality rock masses, the Hoek–Brown strength for D = 1 may be lower than the residual strength. In the Hoek–Brown approach, as the D factor increases, the behaviour is cohesion weakening friction weakening; however, our work suggests that the behaviour for higher quality rock masses is cohesion weakening friction strengthening. This statement applies to the synthetic material, and laboratory evidence suggests that it also applies to real rock masses.

INTRODUCTION In recent times, the incidence and prevalence of thyroid disorders has been increasing in the Indian population. Autoimmune thyroiditis or Hashimoto’s thyroiditis is one of the most common causes of thyroid disease. Antithyroid antibodies rarely develop before 20 years of age, but they may be a prelude to the development of subsequent hypothyroidism. It is universally known that iodine deficiency causes hypothyroidism. However, sustained unnecessary iodine supplementation may be harmful. Goitre, thyroid dysfunction (both hypo- and hyperthyroidism) and thyroid autoimmunity have been reported as a result of sustained supplementation in the iodine-replete state. Data on the impact of iodisation on thyroid function in adults is sparse. A study was conducted with an objective to estimate the problem of thyroid autoimmunity in patients who presented to the OPD. PATIENTS AND METHODS Patients who presented to the surgical OPD with clinical features of thyroid disease were included in the study after obtaining informed consent. Demographic details and clinical features of thyroid disease were noted. Thyroid status was estimated with the help of serum levels of thyroid stimulating hormone (TSH), free l-thyroxine (FT4), and free tri-iodothyronine (FT3). Autoantibodies to thyroid peroxidase (Anti-TPO) were estimated. Findings were tabulated and analysed. RESULTS AND CONCLUSION The prevalence of antibody positivity was 69.7% (209 out of the 300 patients) in this study. Among age-groups, the maximum prevalence was found in the third decade of life (75/99 patients, 75.8%). Among those who were antibody-positive, 69.9% were euthyroid, 26.8% were hypothyroid and 3.3% were thyrotoxic. Hypothyroidism (elevated S. TSH) had a significant positive correlation (r = 0.324, p = 0.003) with antibody-positivity (elevated S. AMA).

Double pass solar air heater (DPSAH) consisted of rectangular duct provided with artificial roughness on both side of the absorber plate has been experimentally investigated. Circular ribs of aluminium wire is used to provide roughness to increase heat transfer coefficient between absorber plate and air. Ribs are attached to absorber plate at four different angle of attackbetween 30° to 75° . Experiment is carried out over the range of Reynolds Number from 4900 to 12000, and relative roughness height (e/Dh) varies from 0.022 to 0.044. Experimentally different values of Nusselt number(Nu). and friction factor(fr) have been determined for various parameters. The enhance-ment in heat transfer and increment in the friction factor values of Nusselt number and friction factor have also been compared with the smooth one.

The thermohydraulic performance of artificially roughened equilateral triangular solar air heater duct has been investigated and the comparision of the same has been presented with that of a conventional smooth solar air heater duct. The range of relative roughness height (e/Dh) is from 0.021 to 0.043, value of angle of attack (α) and relative roughness pitch (p/e) has been 30° and 8 respectively. The range of Reynolds number is from 5600 to 28000 and aspect ratio of the duct is 1.15. It has been found that the thermohydraulic performance of artificially roughened triangular solar air heater duct is always more than that of the smooth absorber plate in the range of Reynolds number investigated. Keywords-Thermohydraulic performance; Artificial roughness; Solar air heater; Triangular duct.

Seismic shaking induces stress changes in rock and soil slopes, which when combined with existing static stresses, may exceed the available strength and cause failure. Although one of the greatest hazards during strong earthquakes is associated with consequences of triggered landslides and natural slope failures, existing data seem to indicate that earthquakes are not a credible stability hazard for open pit slopes. Because regulations require investigation of slope stability under earthquake loading, relatively simple quasi-static analyses are typically carried out. The quasi-static analysis of the effect of seismic shaking on stability of slopes is usually too conservative. Thus, the mines primarily rely on empirical evidence when considering seismic hazard in the design of the open pit slopes. However, it is important to understand the reasons for relatively good performance of open pit slopes compared to multiple evidences of landslides during historical earthquakes, but also to determine, using a proper methodology, the conditions when open pit slope stability can be at risk during seismic shaking. This paper provides, based on mechanical principles (using numerical models), a rationale to explain field observations that indicate relatively small effect of earthquakes on stability of open pit slopes, and also investigates the level of conservatism in the predictions of the quasi-static analyses as a function of important ground motion parameters. First, the increased demand in terms of dynamic stresses is quantified as a function of pit/slope geometry (topographic amplification) and amplification by wave trapping due to difference in stiffness of geological layers. It is shown that open pits have an advantage due to their three dimensional circular/elliptical geometry and less amount of weathered material close to the surface as compared to natural slopes. Next, a typical slope is subjected to suite of ground motions covering a wide range of peak ground accelerations and frequency contents. The dynamic Factor of Safety is calculated based on displacement criteria. After comparing the reduction in dynamic Factor of Safety with different earthquake intensity parameters, peak ground velocity (PGV) appears to be the parameter that best correlates with seismic risk for slopes. Finally, it is shown that the conventional approach of pseudo−static analysis using earthquake-magnitude-based seismic coefficients results in Factors of Safety that are almost always conservative, and often too conservative.