Biodiesel, a fuel that can be made from renewable biological sources such as vegetable oils or animal fats, has been recognized recently as an environment friendly alternative fuel for diesel engines. In this paper, we describe a study that compared exhaust emissions from in-use heavy trucks fueled with a biodiesel blend with those from trucks fueled with petroleum diesel. The biodiesel blend tested is a mixture of 35% biodiesel and 65% petroleum diesel, a blend designated as B35. The study is based on the field test results from West Virginia University's Transportable Heavy Duty Chassis Dynamometer Emissions Testing Laboratory and sponsored by the U.S. Department of Energy. The heavy trucks we tested performed well when the originally equipped compression-ignition engine (diesel engine) was fueled with B35 without any engine modifications. Fuel economy (in terms of gallon per mile) of the two fuels was about the same. The emissions test results have shown that the heavy trucks fueled by B35 emitted significantly lower particulate matter (PM) and moderately lower carbon monoxide (CO) and hydrocarbon (HC) than the same trucks fueled by no. 2 diesel (D2). Oxides of nitrogen (NO x ) emissions from B35 and D2, however, were generally in the same level. Emissions variations from two different engine models and two driving cycles were also observed. Although we recommend more tests for biodiesel vehicles, the data obtained in this study indicate that biodiesel has promise as an emissions-reducing alternative fuel for diesel engines.

The use of alternative fuels is considered to be an effective measure to meet strict emissions regulations of particulate matter (PM) and oxides of nitrogen (NO x ). In response to these requirements, emissions data from inuse alternative fuel and diesel-powered heavy-duty vehicles have been measured and collected from 32 transit agencies in 17 states using the two West Virginia University (WVU) transportable heavy-duty vehicle emissions testing laboratories (THDVETLs). More than 600 tests have been performed on over 300 buses and heavy trucks operating on alternative fuels such as natural gas, methanol, and ethanol and also operating on conventional fuel diesel. Regulated emissions of PM, NO x , carbon monoxide (CO), and total hydrocarbon (HC) have been measured and analyzed. In this study, emissions data from alternative fuel buses and diesel control buses are carefully compared. The results show that natural gas, methanol, and ethanol have a strong potential to reduce PM and NO x emissions levels.

No abstract

Connecting with others makes people happier, but strangers in close proximity often ignore each other. Prior research (Epley & Schroeder, 2014) suggested this social disconnection stems from people misunderstanding how pleasant it would be to talk with strangers. Extending these prior results, in a field experiment with London-area train commuters, those assigned to talk with a stranger reported having a significantly more positive experience, and learning significantly more, than those assigned to a solitude or control condition. Commuters also expected a more positive experience if they talked to a stranger than in the solitude or control conditions. A second experiment explored why commuters nevertheless avoid conversation even when it is generally pleasant. Commuters predicted that trying to have a conversation would be less pleasant than actually having one because they anticipated that others would be uninterested in talking. These experiments clarify the precise aspects of social interaction that may be misunderstood. People may avoid pleasant conversations with strangers because of miscalibrated concerns about starting them.

No abstract