No abstract

Optical techniques used for the measurement of the optical properties of blood are of great interest in clinical diagnostics. Blood analysis is a routine procedure used in medical diagnostics to confirm a patient's condition. Measuring the optical properties of blood is difficult due to the non-homogenous nature of the blood itself. In addition, there is a lot of variation in the refractive indices reported in the literature. These are the reasons that motivated the researchers to develop a mathematical model that can be used to predict the refractive index of human blood as a function of concentration, temperature and wavelength. The experimental measurements were conducted on mimicking phantom hemoglobin samples using the Abbemat Refractometer. The results analysis revealed a linear relationship between the refractive index and concentration as well as temperature, and a non-linear relationship between refractive index and wavelength. These results are in agreement with those found in the literature. In addition, a new formula was developed based on empirical modelling which suggests that temperature and wavelength coefficients be added to the Barer formula. The verification of this correlation confirmed its ability to determine refractive index and/or blood hematocrit values with appropriate clinical accuracy.

The performance of a solar assisted heat pump dryer integrated with biomass furnace has been designed and evaluated for drying red chillies, and drying kinetics of red chillies were evaluated. The red chillies were dried from 22 kg with moisture content of 4.26 db to moisture content of 0.08 db which needed 11 hours, with the average drying chamber temperature, drying chamber relative humidity, and an air mass flow rate of 70.5°C, 10.1%, and 0.124 kg/s, respectively, while the open sun drying needed 62 hours. Compared to open sun drying, this dryer yielded 82% saving in drying time. The drying rate, the specific moisture extraction rate, and thermal efficiency of the dryer were estimated in average to be about 1.57 kg/h, 0.14 kg/kWh, and 9.03%, respectively. Three mathematical models, the Newton, Henderson-Pabis, and Page models, were fitted to the experimental data on red chillies dried by solar assisted heat pump dryer integrated with biomass furnace and open sun drying. The performance of these models was evaluated by comparing the coefficient of determination (R2), mean bias error (MBE), and root mean-square error (RMSE). The Page model gave the best results for representing drying kinetics of red chillies.

No abstract

The physical properties of hydrocarbon mixtures are of great importance in the field of science and technology. Knowing the refractive index of multicomponent liquid mixtures is essential in order to characterize these systems; however, there is a limited amount of experimental data regarding their optical properties. The present study provides precise experimental measurements of the refractive indices of three hydrocarbon compounds: 1,2,3,4-tetrahydronaphthalene (THN), isobutylbenzene (IBB), and dodecane (nC12). Sixty-three compositions (36 ternaries +27 binaries) were prepared and investigated along with their three pure components using a wide range of concentrations, temperatures and wavelengths. The refractive indices were measured using the multiwavelength Abbemat refractometer. The experimental data were then used to develop and validate new mathematical correlations which can be used to predict the refractive index of ternary mixtures as a function of concentration, temperature, and wavelength. There was a strong correlation between the experimental data and the predictive values with average residual values of ± 1.55·10–3. This study also investigated the relative validity of the experimental measurements of the refractive indices with theoretically estimated values using mixing rules and data from the literature. The experimental values were in substantial agreement with the predictive equation values with deviations of ± 2.50·10–3.