Harvard of today, from the undergraduate point of view;

"Publications concerning Harvard": p. 100-101.Mode of access: Internet

The Impact of Household Appliances and Devices: Consider Their Reactive Power and Power Factors

In recent years, there has been a noticeable change in the flow of reactive power in power network systems around the world. A part of this change could be due to residential household appliances, particularly with the increasing use of LEDs and battery-powered devices with switch-mode power supplies. This study investigates the power characteristics of 56 modern appliances and devices. The results indicate a major change in the electrical behavior across these household appliances and devices. In particular, LED technology and switch mode power supplies are likely to increase household reactive power injection, which will increase as penetration of these products grows, particularly with government programs often incentivizing their uptake. A variety of avenues are available to address these issues, including governments requiring appliance manufacturers to display the power factor of their appliances or device. In time, appliance manufacturers may develop new products that have built-in power factor correction. Overall, the findings highlight how efforts to be sustainable with energy use may have unintended consequences on other parts of the electrical system that need to be considered for the sustainability of the system as a whole

A multipollutant evaluation of APEX using microenvironmental ozone, carbon monoxide, and particulate matter (PM2.5) concentrations measured in Los Angeles by the exposure classification project

This paper describes an operational evaluation of the US Environmental Protection Agency’s (EPA) Air Pollution Exposure Model (APEX). APEX simulations for a multipollutant ambient air mixture, i.e. ozone (O3), carbon monoxide (CO), and particulate matter 2.5 microns in diameter or less (PM2.5), were performed for two seasons in three study areas in central Los Angeles. APEX predicted microenvironmental concentrations were compared with concentrations of these three pollutants monitored in the Exposure Classification Project (ECP) study during the same periods. The ECP was designed expressly for evaluating exposure models and measured concentrations inside and outside 40 microenvironments. This evaluation study identifies important uncertainties in APEX inputs and model predictions useful for guiding further exposure model input data and algorithm development efforts. This paper also presents summaries of the concentrations in the different microenvironments

A multipollutant evaluation of APEX using microenvironmental ozone, carbon monoxide, and particulate matter (PM_2.5) concentrations measured in Los Angeles by the exposure classification project

<p>This paper describes an operational evaluation of the US Environmental Protection Agency’s (EPA) Air Pollution Exposure Model (APEX). APEX simulations for a multipollutant ambient air mixture, i.e. ozone (O₃), carbon monoxide (CO), and particulate matter 2.5 microns in diameter or less (PM_2.5), were performed for two seasons in three study areas in central Los Angeles. APEX predicted microenvironmental concentrations were compared with concentrations of these three pollutants monitored in the Exposure Classification Project (ECP) study during the same periods. The ECP was designed expressly for evaluating exposure models and measured concentrations inside and outside 40 microenvironments. This evaluation study identifies important uncertainties in APEX inputs and model predictions useful for guiding further exposure model input data and algorithm development efforts. This paper also presents summaries of the concentrations in the different microenvironments.</p