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It is well known that small amounts of surfactants, such as 1-Octanol, in the aqueous solution can increase the absorption rate significantly. In this paper, experimental data were obtained for absorption of water vapour into an aqueous LiBr solution with different concentrations of 1-Octanol. An experimental rig was specifically designed and developed in this work in order to investigate the effect of surfactant (1-Octanol) on the enhancement of the heat and mass transfer in the absorption process, in addition to, the investigation of the impact of the use of magnetic stirrer inside the absorber. The experimental rig for this study was based on the refrigeration mode of the intermittent vapour absorption system. In order to study the heat and mass transfer in water-lithium bromide vapour absorption air conditioning systems, it was necessary to monitor the concentration of the solution continuously. As a consequence, two procedures for obtaining the LiBr solution concentration were used. The first method was based on the measurement of the density and temperature of the solution, while the second was based on its electrolyte conductivity and the temperature. The experimental results showed that the surfactant concentration has a significant effect on the absorption rate; this is called the Marangoni instability. It has been concluded that, in order to clarify the absorption enhancement phenomenon, it is necessary to understand the physicochemical aspects of the absorption process and the effect of surfactants on the enhancement of such process. Additionally, it has been concluded that new approaches are needed to explain the observed behaviour.
Monitoring of structures is an important challenge faced by researchers worldwide. This study developed a new structural health monitoring system which utilized the use of microprocessors, wireless communication, transducer, and cellular transmission that allows remote monitoring. The developed system will facilitate the monitoring process at any time and in any location with less human interference. The system is equipped with data processing subsystem which works on detection of structural behavior irregularity, defects, and potential failures. The system was tested using strain gages to measure the developed strains in different applications and structural models. The results developed using the new system showed that the generated readings from the system followed correctly the expected trend according to structural concepts. The developed system accomplished the desired features of lower cost, less power, reduced size, flexibility and easier implementation, remote accessing, early detection of problems, and simplified representation of the results.
There is a huge investment in our infrastructure that is vital to
our social and economic life. However, the aging and deterioration of the
structures require implementing a damage detection system to monitor their
structural integrity. In this study, a new alarming system was developed as part of
a structural health monitoring system and installed in a scaled-down structure
models. The designed system incorporated microprocessors, wireless
communication, transducer, and cellular transmission that allow remote
monitoring. The developed system facilitates continuous monitoring process of
any part of structures and controlled remotely from any location. The system
was equipped with data processing subsystem that detects structural behavior
irregularity, defects, and potential failures. The system was tested using Linear
Variable Differential Transformer (LVDT) for deflections and using strain gages to
measure the developed axial and flexural strains in different structural
models. Filtering algorithm was used to filter graphs and the data gathered in
each loading stage was averaged and plotted to show the abrupt change in the
values. The filtering system helps the alarming system to have a clear
prediction of possible irregularities. The developed system provides the
desired features of low cost, low power, small size, flexibility and easy
implementation, remote accessing, early detection of problems, and simplified
representation of the results.