Particulate matter reduction efficiency analysis of sprinkler system as targeted control measures for construction activity

Air pollution caused by the construction industry in the form of particulate matter (PM) has increased to an alarming level. The effects on the health of construction workers are found to be hazardous despite the current advancement in construction methods and practices. In particular, the efficiency of existing control measures for reducing PM from various construction activities has not been improved to the desired level. This study investigated the factors that influence the efficiency of a sprinkler system-based control measure when water spraying and dust suppressant solutions are used. The real-time PM exposure was measured during hollow-block cutting activity using Alphanese OPC-N3 sensors in dust chamber. The dust suppressant suppresses dust particles by initially forming a solidified film on the particle surface, and the high cohesion of this film enhances the suppression rate by promoting dust particle coagulation. It was observed that when using a dust suppressant, the PM concentration at 100 bar exceeded concentrations at other pressures, resulting in increased efficacy in reducing PM10. Additionally, water spraying at 115 bar was determined to be the optimal control measure for achieving a significant percentage of PM reduction in a shorter period. These findings can be highly beneficial if the water sprinkler system can be modified into a smart mobility-based sprinkler system either ground-based or drone-based at construction sites in improving PM reduction efficiency particularly on high PM emitting activities.

Numerical Analysis on Piezoelectrically Driven Jet Dispensing Mechanism for Nanoliter Droplet of High Viscosity Liquid

Various research on a dispenser head applied with the technology of piezoelectric ceramics which has high response, force generation and resolution have been actively conducted. A piezoelectric dispenser head for functional high viscous liquid generates micro droplets utilizing a different mechanism with conventional valves. This mechanism makes it difficult to calculate the pressure build-up and flow quantity. Because of this difficulty, proper displacement of a tappet cannot be selected and the displacement of the piezoelectric ceramic is being used with excessive amplification. To address these issues, a piezo dispenser head has been modeled to numerically analyze this mechanism. The mechanism has been simulated to calculate the pressure build-up and flow quantity. In addition, the load on the tappet was calculated, and the appropriate displacement of the tappet was confirmed. In this study, we have succeeded in numerically analyzing the mechanism of the piezoelectric dispenser head and we confirmed that the displacement of the appropriate tappet is about 200 μm; at this time the load on the tappet is about 3.7 N and the droplet volume is about 19.89 nL.