Dynamic properties such as natural frequencies and mode shapes are directly affected by damage in structures. In this paper, changes in natural frequencies and mode shapes were used as the input to various objective functions for damage detection. Objective functions related to natural frequencies, mode shapes, modal flexibility and modal strain energy have been used, and their performances have been analyzed in varying noise conditions. Three beams were analyzed: two of which were simulated beams with single and multiple damage scenarios and one was an experimental beam. In order to do this, SAP 2000 (v14, Computers and Structures Inc., Berkeley, CA, United States, 2009) is linked with MATLAB (r2015, The MathWorks, Inc., Natick, MA, United States, 2015). The genetic algorithm (GA), an evolutionary algorithm (EA), was used to update the damaged structure for damage detection. Due to the degradation of the performance of objective functions in varying noisy conditions, a modified objective function based on the concept of regularization has been proposed, which can be effectively used in combination with EA. All three beams were used to validate the proposed procedure. It has been found that the modified objective function gives better results even in noisy and actual experimental conditions.

Water is the basic need of life. Chlorination is a well-known disinfection technique for potable water due to its cheap availability. Yet, some aspects are harmful to human health and found carcinogenic. An attempt has been made to quantify the occurrence of two prominent Chlorination Disinfectant byproducts (DBPs), i.e., Trihalomethanes (THMs) and Trihalo acetic acids (THAAs) in the water distribution network of galvanized iron Pipes Medium using GC-Mass Spectrometry equipped with Electron Capture Detector (ECD). Two filtration setups, i.e., granular activated carbon (GAC) and a pack of sand, were evaluated as abatement techniques were introduced for removing these chlorination disinfectants by products according to the water source and pipe medium used. The chromatogram with mass spectrometry hints at the occurrence of these two disinfectants' by-products and the filtration media's weightage and removal capacity. A combination of granulated activated carbon accompanied with sand media and based on gravel was found to be the more feasible and efficient setup to remove chlorine disinfectant product impurities for the galvanized iron pipes distribution network medium.

Two prominent chlorination disinfection byproducts (DBPs)—trihalomethanes and trihaloacetic acids—are formed in drinking water when chlorine reacts with other constituents. The production of these DBPs has emerged as a significant public health concern. At the same time, disinfection of potable water remains essential as a safety measure to effectively combat waterborne diseases by eliminating pathogenic microorganisms. To regulate the formation of these two major DBPs in the water distribution network, one of the key factors is the nature of the pipe material used, along with the implementation of cost-effective abatement techniques. This study compared two types of potable water supply pipe materials—galvanized iron and high-density polythene pipes—for their role in the production of chlorine DBPs. Both materials showed different weightage ratios of DBP formation when chlorinated water came into contact with the inner surface of distribution pipes. Two filtration setups, i.e., granular activated carbon (GAC) and sand filtration media, were evaluated as abatement techniques for removing DBPs, depending on the water source and pipe material used. The findings contribute to understanding the differences in the generation of major DBP species under known supply media, as well as the removal efficiency of DBP precursors by GAC and sand filtration. Overall, the results reveal that GAC and sand filtration media can serve as low-cost and sustainable alternatives to costly, complex filtration membranes for DBP removal.