Selective catalytic reduction (SCR) is an emissions control technique that primarily reduces harmful emissions of oxides of nitrogen (NOx). To maintain SCR performance, catalyst layers maybe added, removed, or replaced to improve NOx reduction efficiency. To make these changes, power plants must be temporarily shut down, and SCR maintenance during scheduled power plant outages can be very expen...

replacement of a tractor is an influential factor affecting timely farm operation. the accurate prediction of repair and maintenance costs is essential to selection of a replacement model. this study used empirical data for 60 two-wheel drive (2wd) tractors from astan ghods-e razavi agroindustry. the types and numbers of tractors used were the massey ferguson 285 (17), fiat (10), john deere 314...

Abstract The novel aircraft architectures for Urban Air Mobility (UAM), combined with pure on-demand operations, mean a significant change in operation and maintenance compared to traditional airliners. Future flight missions related variables such as the position or utilisation are unknown operation. Consequently, existing methods optimise assignment planning cannot be transferred. This study ...

introduction: hospitals as important sector of health care system has special location in health economic science. increasing of the operational costs in hospital and limitation in financing cause that hospital as an economic firm use cost analysis and prepare effective using of resource and boost productivity. therefore this study was conducted to calculate daily- patient hotel cost in hospita...

In this paper several control strategies for nitrogen removal are proposed and evaluated in a benchmark simulation model of an activated sludge process. The goal is to determine which control strategy delivers better performance with respect to plant operating costs. In the study, constant manipulated variables and various PI and feedforward control strategies are tested and compared with predi...