Analysis of solar radiation measurements at EI-Kharga (250 N, 300E), Egypt

Daily global solar. radiation data of EI-Kharga for five year (1984-88) have been processed, analysed and classified into eight radiation levels spaced at an interval of 4.19 MJ m-2 day-l. Mean annual monthly and daily total the diurnal variation, and the frequency distribution of daily totals of global solar radiation are computed and discussed. A correlation between the hourly values of the clearness and diffuse indices were obtained and the recommended correlation ,equations were also given. The, results presented in this analysis are encouraging since they Indicate that periods of several days of low radiation of less than 8.38 MJm , day are rare. This In turn means that the weather sequence variations are not expected, to be of great Importance when considering the storage problems Involved In solar process design.

Analysis and correlation of ultraviolet solar radiation from routine meteorological measurements over Egypt

For three years (1990-92) measurements of the monthly average daily global, G, and ultraviolet, UV, solar radiation incident on a horizontal surface at Cairo (30°15'N, 31°17'E) and Aswan (23°58'N, 32°47'E) are presented. processed and analysed. It was found that the computed monthly average daily values for the obtained solar radiation components, G and UV, were (18.1 MJ/m2, 0.55 MJ/m2, for Cairo and (22.1 MJ/m2, 0.71 MJ/m2, for Aswan. The effect of atmospheric dust on the measured solar radiation components is also investigated and discussed. The ratio of the ultraviolet to global radiation (UV/G) are calculated and compared with other sites in the Arabian Peninsula. A regression analysis has been done to find a correlation between G and UV at the selected sites during the three year period and the recommended correlation equations have also been stated. Since the meteorological measurements of UV solar radiation are not available over Egypt. except at Cairo (Lower Egypt) and Aswan (Upper Egypt) stations, our correlation equations can be used to calculate this component from the available global solar radiation measurements at any site in the two zones of Upper and Lower Egypt.

Some climatological characteristics of the changing pattern of temperature in Bangladesh – A diagnostic approach

Based on climatological data of maximum and minimum temperatures of seventeen stations for a period of 60 years (1949 - 2008), obtained from Bangladesh Meteorological Department (BMD), the changing pattern of temperature in Bangladesh has been investigated. Some characteristics of annual variation and spatial distribution of mean monthly minimum, mean monthly maximum and mean monthly temperature, annual variation and spatial distribution of mean monthly amplitude of temperature have been explained. The characteristics of changing pattern of temperature such as standard deviation, coefficient of variation, ratio between mean monthly maximum and mean monthly minimum temperatures have been studied. The run of the temperature in different stations for the years 1949-2008, the periodicity of mean annual temperature and mean decade deviations have been discussed. The integral curve of mean annual temperature for Dhaka has been prepared and explained. Regression analysis for mean monthly temperature of January, April, July and October for the stations Sylhet, Chittagong, Khulna and Rangpur with Dhaka have been analyzed. Some linear correlation equations have been deduced. In the investigation, attempts (as far as possible) have been made to explain the synoptic cause of the changing pattern of temperature in Bangladesh.

Correlations between the Physical Mechanical Properties of Greek Dimension Stones

This study focuses on the investigation of possible relations betweenthe physical mechanical properties of natural stones from various places in Greece, i.e., limestones, marbles, sandstones and schists. Specimens were prepared to perform laboratory tests according to the applicable EN. Overall and “by stone type” correlation equations were established between flexural strength under concentrated load valueswithout and either after freeze–thaw cycling or thermal shock, indicating a linear and a powerrelationship, respectively. A power function was establishedbetween flexural strength under a concentrated load and under a constant moment. Results have also shown that water absorption increases linearly with open porosity.

In Vitro Neutral Detergent Cellulase Method and Chemical Composition to Predict In Vivo Fermentable Organic Matter of Roughages

In vivo fermentable organic matter (FOM) reflects the energy production and the potential of rumen’s microbial protein synthesis. However, the in vivo method with fistulated animals for FOM measurement compromises animal welfare and is laborious as well as expensive. Although the alternative in situ nylon bag technique has been widely used, it is also costly and requires rumen liquor. Therefore, the present study was performed to compare the in situ nylon bag technique with the in vitro neutral detergent cellulase (NDC) method or chemical composition to estimate in vivo FOM of roughages. For this purpose, we selected 12 roughages, including six each from forages and crop residues. Our results have shown the strong correlation equations between FOMin situ and FOMNDCFOM NDC of forages (n =6; R2 = 0.79), crop residues (n =6; R2 = 0.80), and roughages (n = 12; R2 = 0.84), respectively. Moreover, there were also strong correlations between the chemical composition of roughages and FOMin situ(n = 12; R2 = 0.84–0.93) or FOMNDC (n = 12; R2 = 0.79–0.89). In conclusion, the in vitro NDC method and chemical composition were alternatives to in situ nylon bag technique for predicting in vivo FOM of roughages in the current experiment.

Free Convection Heat Transfer from Horizontal Cylinders

The results of experimental investigation of free convection heat transfer in a rectangular container are presented. The ability of the commonly accepted correlation equations to reproduce present experimental data was tested as well. It was assumed that the examined geometry fulfils the requirement of no-interaction between heated cylinder and bounded surfaces. In order to check this assumption recently published correlation equations that jointly describe the dependence of the average Nusselt number on Rayleigh number and confinement ratios were examined. As a heat source served electrically heated horizontal tube immersed in an ambient fluid. Experiments were performed with pure ethylene glycol (EG), distilled water (W), and a mixture of EG and water at 50%/50% by volume. A set of empirical correlation equations for the prediction of Nu numbers for Rayleigh number range 3.6 × 104 < Ra < 9.2 × 105 or 3.6 × 105 < Raq < 14.8 × 106 and Pr number range 4.5 ≤ Pr ≤ 160 has been developed. The proposed correlation equations are based on two characteristic lengths, i.e., cylinder diameter and boundary layer length.

A Study of Fluctuation and Expansion Ratios for Gas-Solid Fluidized Columns

The fluctuation and expansion ratios have been studied for cylindrical gas-solid fluidized columns by using air as fluidizing medium and Paracetamol as the bed material. The variables were the column diameter (0.0762, 0.15, and 0.18 m), static bed height (0.05, 0.07, and 0.09 m), and air velocity to several times of minimum fluidization velocity. The results showed that both the fluctuation and expansion ratios had a direct relation with air velocity and an inverse one with column diameter and static bed height. A good agreement was between the experimental results and the calculated values by using the correlation equations from the literature.

OXIDATION OF THE ACRYDINE BY PEROXYDECANIC ACID IN VARIOUS ORGANIC SOLVENTS

The rate of oxidation reaction of the acrydine with peroxydecanoic acid in various organic solvents was studied. It has been found the effective rate constants (k) and the activation energy (Ea) of studied process. Between the parameters of the transition state ΔН≠ and ΔЅ≠ is some linear relationship, indicating on the presence of the counteraction effect in our series of experiments. The rate of oxidation and activation energy inflation of solvation peroxyacid and acrydine was calculated. The reaction medium affects the rate of oxidation. Correlation equations between the rate constants of the reactions in study and the physicochemical parameters of the solvents were proposed. The correlation equation for effective rate constants and the basic physicochemical parameters of solvents at 318 K has the form: k = –388.8034 + (1662.9800 ± 313.4735)f(n) – (221.2833 ± 70.3626)f(ε) + (0.8092 ± 0.1145)B N = 8; R = 0.9982; S = 3.0727; F = 5.2713. The polarizability, polarization and basicity, of solvent have effect on the oxidation process. The influence of electrophilicity polarization and molar volume on the rate of oxidation of acrydine decay process is negligible. Correlation equations for effective rate constants for other temperatures are similar. The correlation equation for effective energies (Ea) of activation and the basic physicochemical parameters of solvents has the form: Eа = 104.6924 + (50.3320 ± 12.6429)f(ε) + (0.0557 ± 0.0137)B – (0.1201 ± 0.0188)δ2 – (0.5573 ± 0.0782)Vм N = 9; R = 0.9663; S = 2.8058; F = 1.3842. The polarizability, basicity, molar volume and Hildebrand's function of solvent have effect on the energy of activation process. The proposed correlation equations relate the parameters of the transition state of the oxidation process and the physic-chemical parameters of solvents.