An Optical Transistorized Ignition System

Annually about 100 million automobiles suck in vast quantities of air and eject it in a contaminated state. When, pollutants are measured by weight,¹ it seems that the automobile is the nation’s worst polluter. The EPA estimates that in 1969 motor vehicles accounted for 98 million tons of CO, 8.7 million tons of NO_x and more than 17 million tons of HC.     

Urban early adolescents,crowding and the neighbourhood experience: A preliminary investigation

This interview study focused on urban early adolescents' conscious experiences of high density conditions. Thirty children residing in apartments in two boroughs of New York City (Brooklyn and Manhattan), participated in this study. Control variables included income level, age, family constellation, and length of residence. Sex, apartment density, building size and neighbourhood density served as classification variables. The interview lasted approximately forty minutes and addressed the following issues.Personal conceptualizations and definitions of crowding.Evaluation of the children's perceived neighbourhood.Peer relationships.Perceived social and physical opportunities and constraints.Interviews were tape recorded, transcribed and content analyzed.The children's conceptualizations of crowding emphasized large numbers of people, spatial restriction and an aversive experience of the situation as relevant components of the crowding construct. The restriction of behavioural choice as it relates to goal postponement and the child's efforts to come to terms with larger organizational social structures, underlined the interpretation of crowding as a socio-physical stressor. While information overload was depicted as another relevant characteristic of crowding situations, its aversive experience was mediated by the presence of known others. Even though this diversity on social and physical levels was often experienced as stressful, it was also positively viewed in situations where interpersonal contact or a sense of familiarity were not overriden by other situation demands.Boys tended to spend more time in their neighbourhood engaged in a broader range of activities than girls. In this sample, boys also took less part in structured group activities and rated their neighbourhoods somewhat more positively than girls. Girls experienced less freedom and more social restrictions in exploring and actively interacting with their extended surroundings than boys.The issues of movement and situationally imposed behavioural restriction were central themes in children's conscious experiences of high density situations. Emphasis was placed on physiological arousal linked to the perception of aversive social qualities of high density situations. It appears that an increase in the need to act out is more a function of the child's awareness of having to conform to external norms, or experiencing a loss of perceived social control in situations where vigilance is required, than a clear cognisance of spatial restrictions.The investigation of the impact of high density conditions on the child's sociocognitive development and identity formation is viewed as potentially fruitful directions for future research.     

A quantitative description of vehicle exhaust particle size distributions in a highway tunnel

During the period May 18-May 22, 1999, a comprehensive study was conducted in the Tuscarora Mountain Tunnel on the Pennsylvania Turnpike to measure real-world motor-vehicle emissions. As part of this study, size distributions of particle emissions were determined using a scanning mobility particle sizer. Each measured size distribution consisted of two modes: a nucleation mode with midpoint diameter less than 20 nm and an accumulation mode with midpoint diameter less than 100 nm. The nucleation and accumulation components in some distributions also exhibited second maxima, which implies that such particle size distributions are superpositions of two particle size distributions. This hypothesis was utilized in fitting the particle size distributions that exhibited second maxima with four lognormal distributions, two for the nucleation mode and two for the accumulation mode. The fitting assumed that the observed particle size distribution was a combination of two bimodal log-normal distributions, one attributed to the heavy-duty diesel (HDD) vehicles and another attributed either to a different class of HDD vehicles or to the light-duty spark ignition vehicles. Based on this method, estimated particle production rates were 1.8 x 10(13) and 2.8 x 10(14) particles/vehicle-km for light-duty spark ignition and HDD vehicles, respectively, which agreed with independently obtained estimates.     

Landfill leachate effects on sorption of organic micropollutants onto aquifer materials

The effect of dissolved organic carbon as present in landfill leachate, on the sorption of organic micropollutants in aquifer materials was studied by laboratory batch and column experiments involving 15 non-polar organic chemicals, 5 landfill leachates and 4 aquifer materials of low organic carbon content. The experiments showed that hydrophobic organic micropollutants do partition into dissolved organic carbon found in landfill leachate potentially increasing their mobility. However, landfill leachate interacted with aquifer materials apparently increases the sorbent affinity for the hydrophobic micropollutants. The combination of these two mechanisms affected the observed distribution coefficients within a factor of two, in some cases increasing and in other cases decreasing the sorption of the chemicals. No means for prediction of the effect is currently available, but from a practical point of view, the effect of landfill leachate on retardation of organic micropollutants in aquifer material seems limited.     

Initial results from a multi-institutional collaboration to monitor harmful algal blooms in South Carolina

The rapid rate of development in the South Carolina (SC) coastal zone has heightened public concern for the condition of the state's estuaries, and alerted scientists to the potential that novel and adverse effects on estuarine ecosystems may result. Although well-developed databases from long-term monitoring programs exist for many variables valuable in predicting and following system responses, information on phytoplankton distributions in SC estuaries has lagged. Knowledge of the dynamical relationship between environmental (e.g., nutrient quantity and quality) and biological (e.g., grazing) regulation, and phytoplankton biomass and composition is critical to understanding estuarine susceptibility to eutrophication or harmful algal blooms (HABs). Recently, SC scientists from federal, state, and academic institutions established a collaborative monitoring program to assess HAB distribution and ecology statewide. The South Carolina Harmful Algal Bloom Program includes: a) intensive temporal monitoring at areas of known HAB occurrence or those exhibiting symptoms potentially related to HABs (e.g., prevalent fish lesions), b) extensive spatial monitoring in coordination with existing statewide efforts, c) a citizen volunteer monitoring network, d) nutrient response bioassays, and e) laboratory-based physiological experiments on HAB isolates. By combining trip-wire surveillance and rapid response systems, routine monitoring of environmental parameters and HAB distribution, and process-oriented studies examining the physiological functioning of HAB species, an enhanced understanding of the impact and environmental control of HABs in SC estuaries will be achieved. The application of this approach to studies on the distribution and physiological ecology of a new widespread SC red tide, and to the discovery of several potentially toxic blooms (including Pfiesteria) in SC holding ponds, are described.     

A data integration framework to support Triad projects

Cost‐effective and efficient site remediation and scientifically defensible decisions require site characterizations that are representative of site conditions. The Triad conceptual site model (CSM) is at the center of a continually improving site characterization process that begins during systematic planning and ends after the last data are developed. To gain the full benefit and greatest cost‐effectiveness, the process of CSM refinement should be performed in real time. Thus, the use of collaborative data is critical for evolving and maturing the CSM. In the field, through the use of all available data that are of known quality, a skilled and experienced field team can collect sufficient site information to mature the CSM in a timely manner. To facilitate the planning and execution of such a process, an easily understandable framework is needed to structure data quality that supports scientifically defensible decisions and efficient projects. This article explores such a framework. © 2004 Wiley Periodicals, Inc.     

The organization of integrated environmental research in The Netherlands

This article presents new concepts for the organization of increasingly complex environmental research activities on the institutional, the national, or the international level. An environmental research cycle with four phases, similar to the industrial product cycle, is described, and its implications in managing the interface between research, policy making, and enforcement are depicted. Furthermore, five main themes of future environmental research are proposed, including advanced analytical methods, environmental monitoring, an environmental management information system (EMIS), and the development of ecological targets at a national and a global level. The specific tasks of universities, private organizations, and governmental institutions in the total environmental research area are defined and a structure is proposed to develop collaborative networks.