Essays on Transmittance

Introduction

Spectrophotometry is one of the most common and efficient means of chemical analysis currently used in estimating the concentration of some chemicals. The technique exploits the radiation absorption property of various chemical substances in determining their concentrations. Spectrophotometry is based on Beer-Lambert Law. Beer-Lambert Law is the linear relationship between the absorbance and concentration of an absorbing species (Nair, 2010; Burrows et al., 2013). The mathematical expression of Beer-Lambert Law is shown in equation1 below: A=aλ*b*c Equation 1 In the equation 1 shown above, A represents the measured absorbance, a is the absorptivity coefficient which depends on ...

Introduction

The kinetic characteristics are important for the design of chemical engineering processes. They allow assessing the time required for the reaction and choosing the temperature range suitable for the reaction. The reaction path is observed by measurments the transmittance of the Crystal Violet solution that reacts with sodium hydroxide. The concentration, and the color of the solution changes with the reaction flow, and this is measured by the spectrophotometer.

The data are plotted as concentration - time and logarithm concentration time, and the reaction rate is:

Rate = [Crystal Violet] [Sodium Hydroxide]. Using the excess concentration of one of the reagents, the reaction rate with respect to the other reagent is found from logarithmic plot (Rahul & Chakrabarti ...

Abstract

Photovoltaic (PV) systems are one of the next generation’s renewable energy sources for our world energy demand. PV modules are highly reliable. However, in polluted environments, over time, they will collect grime and dust. There are also limited field data studies about soiling losses on PV modules. The study showed how important it is to investigate the effect of tilt angle on soiling.

The study includes two sets of mini-modules. Each set has 9 PV modules tilted at 0, 5, 10, 15, 20, 23, 30, 33 and 40o. The first set called "Cleaned" was cleaned every other day. ...