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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.