Effect of variable fluid properties on natural convection of nanofluids in a cavity with linearly varying wall temperature

The present study analyzed convective heat transfer and fluid flow characteristics of nanofluid in a two-dimensional square cavity under different combinations of thermophysical models of nanofluids. The right vertical wall temperature is varying linearly with height and the left wall is maintained at low temperature whereas the horizontal walls are adiabatic. Finite volume method is used to solve the governing equations. Two models are considered to calculate the effective thermal conductivity of the nanofluid and four models are considered to calculate the effective viscosity of the nanofluid. Numerical solutions are carried out for different combinations of effective viscosity and effective thermal conductivity models with different volume fractions of nanoparticles and Rayleigh numbers. It is found that the heat transfer rate increases for Models M1 and M3 on increasing the volume fraction of the nanofluid, whereas heat transfer rate decreases for Model M4 on increasing the volume fraction of the nanoparticle. The difference among the effective dynamic viscosity models of nanofluid plays an important role here such that the average Nusselt number demonstrates an increasing or decreasing trend with the concentration of nanoparticle

Correlation between ocular parameters and amplitude of accommodation

Aim: To study the relationship between ocular parameters and amplitude of accommodation (AA) in the peri-presbyopic age group (35-50 years). Materials and Methods: Three hundred and sixteen right eyes of consecutive patients in the age group 35-50 years, who attended our outpatient clinic, were studied. Emmetropes, hypermetropes and myopes with best-corrected visual acuity of 20/20, J1 in both eyes were included. The AA was calculated by measuring the near point of accommodation. The axial length (AL), central anterior chamber depth (CACD) and lens thickness (LT) were also measured. Results: There was moderate correlation (Pearson′s correlation coefficient r = 0.56) between AL and AA as well as between CACD and AA (r = 0.53) in myopes in the age group 35-39 years. In the other age groups and the groups taken as a whole, there was no correlation. In hypermetropes and emmetropes, there was no correlation between AA and the above ocular parameters. No significant correlation existed between LT and AA across different age groups and refractive errors. Conclusion: There was no significant correlation between AA and ocular parameters like anterior chamber depth, AL and LT

Amplitude of Accommodation and its Relation to Refractive Errors

<b>Aims:</b> To evaluate the relationship between amplitude of accommodation and refractive errors in the peri-presbyopic age group. <b> Materials and Methods:</b> Three hundred and sixteen right eyes of 316 consecutive patients in the age group 35-50 years who attended our outpatient clinic were studied. Emmetropes, hypermetropes and myopes with best-corrected visual acuity of 6/6 J1 in both eyes were included. The amplitude of accommodation (AA) was calculated by measuring the near point of accommodation (NPA). In patients with more than &#x00B1; 2 diopter sphere correction for distance, the NPA was also measured using appropriate soft contact lenses. <b> Results:<i> </b></i> There was a statistically significant difference in AA between myopes and hypermetropes (<i> P</i> <0.005) and between myopes and emmetropes (<i> P</i> <0.005) in the 35-39 year age group. In the 40- 44 year age group, there was a significant difference in AA between emmetropes and hypermetropes (<i> P</i> <0.0001), emmetropes and myopes (<i> P</i> <0.01) and hypermetropes and myopes (<i> P</i> <0.0001). In patients above 45 years of age there was no significant difference (<i> P</i> &gt;0.5). <i> </i>Conclusion: Our study showed higher amplitude of accommodation among myopes between 35 and 44 years compared to emmetropes and hypermetrope