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The role of vehicle driver behavior has been ignored in prior energy and environmental policy making. Laboratory procedures that produce the fuel economy estimates posted on every new car sold in the US are designed to preclude the effects of differences between drivers. Yet, every vehicle states the caveat, ''Actual results will vary for many reasons, including driving conditions and how you drive and maintain your vehicle." Eco-driving as means of strategically taking advantage of this variability has been inconsistently defined in conceptual analyses and variously operationalized in empirical analyses. The present research clarifies, synthesizes, and expands on prior definitions of eco-driving to develop a comprehensive and precise definition and typology of eco-driving behaviors. The resultant typology includes six mutually exclusive classes of behavior: driving, cabin comfort, trip planning, load management, fueling, and maintenance. This typology establishes a basis for systematic research to determine energy and climate impacts and develop effective policies and interventions for different types of eco-driving.

The growing market for plug-in electric vehicles (PEVs) features new models of battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) with varying battery sizes and electric driving ranges. How are the various models being used in the real world? A common assumption in PEV impact analysis is that PEV owners will maximize their vehicle's utility by appropriately sizing the battery to their driving needs and by charging their vehicle as much as possible to recover the cost of the vehicle purchase. On the basis of these assumptions, a high correlation between PHEV owner use of the vehicle and the number of plug-in events is expected, and drivers of PHEVs with a small battery are expected to plug in more than do owners of vehicles with a larger battery and similar driving patterns. The assumptions presented are examined through a survey of more than 3,500 PEV owners conducted in California in May and June 2013. The online survey included extensive data on driving and charging behavior using web map questions. Owners of all PEV models on the market, including more than 600 Volts and 800 Prius Plug-Ins, were surveyed. The results show that small-battery PHEV electric vehicle miles traveled are lower than longer-range PHEV or BEV electric vehicle miles traveled not only because of battery size but also because of public charging availability and charging behavior. Higher electric-range PHEV and BEV drivers charge more often and report more charging opportunities in areas where smaller-battery PHEVs could not find chargers.

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Idaho National Laboratory (INL) operates a mass separator that is currently producing high purity isotopes for use as internal standards for high precision isotope dilution mass spectrometry (IDMS). In 2008, INL began the revival of the vintage 1970s era instrument. Advancements thus far include the successful upgrading and development of system components such as the vacuum system, power supplies, ion-producing components, and beam detection equipment. Progress has been made in the separation and collection of isotopic species including those of Ar, Kr, Xe, Sr, and Ba. Particular focuses on ion source improvements and developments have proven successful with demonstrated output beam currents of over 10 lA 138 Ba and 350 nA 134 Ba from a natural abundance Ba source charge (*2.4 % 134 Ba). In order to increase production and collection of relatively high quantities (mg levels) of pure isotopes, several improvements have been made in ion source designs, source material introduction, and ion detection and collection. These improvements have produced isotopes of high purity ([98 %) and in quantities in the tens of micrograms per run. The instrument and results for pure isotope production for IDMS standards will be presented.

Plug-in hybrid electric vehicles (PHEVs), which run on both electricity from the grid and gasoline, are touted as providing some of the societal and environmental benefits of electric vehicles for a large portion of motorists' daily travel while also acting as a transitional technology toward fully electric vehicles. To test analysts' assumptions about how PHEV users will recharge their vehicles, the observed recharging behaviors of 40 households that participated in a PHEV demonstration in Northern California are reported. The recharging behavior across all households' last week of their 4-week PHEV trial period is summarized with regard to the time of day, frequency of plugging in, and electricity demand to recharge the vehicles. Although the means of the frequency distribution of plug-in events among demonstration households are similar to prior recharging assumptions made by analysts, the distributions are not symmetrical about the mean and there exists a large variation in both the average number of times households plugged in per day and the average energy per plug-in event. Further, there is no strong correspondence between the number of daily plug-in events and total daily electricity demand. The range of behaviors reported here supports the contention that the success of PHEVs in meeting energy and emission goals relies as much (or more) on PHEV users' recharging and driving behavior as on PHEV designs.

Isotope dilution mass spectrometry (IDMS) is an analytical technique capable of providing accurate and precise quantitation of trace isotope abundance and assay providing measurement uncertainties below 1 %. To achieve these low uncertainties, the IDMS method ideally utilizes chemically pure ''spike'' solutions that consist of a single highly enriched isotope that is well-characterized relating to the abundance of companion isotopes and concentration in solution. To address a current demand for accurate 137 Cs/ 137 Ba ratio measurements for ''age'' determination of radioactive 137 Cs sources, Idaho National Laboratory (INL) is producing enriched 134 Ba isotopes that are tobe used for IDMS spikes to accurately determine 137 Ba accumulation from the decay of 137 Cs. The final objective of this work it to provide a homogenous set of reference materials that the National Institute of Standards and Technology can certify as standard reference materials used for IDMS. The process that was developed at INL for the separation and isolation of Ba isotopes, chemical purification of the isotopes in solution, and the encapsulation of the materials will be described.