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A learning community was developed to enhance the teamwork and communication components of a freshman design course. The learning community was comprised of students from a freshman design course, a freshman graphics course, and a high school technology course. Design teams were formed by combining three to four students from each of these courses. These teams were required to research, design, build, and test a specified product. The high school and university students communicated only using e-mails and Internet conferencing. This paper outlines how the learning community is implemented, describes three design projects, and presents the assessment methods. Assessment reveals that university students who participate in the learning community have a better understanding and confidence in the technical aspects of the design project than the students who do not participate in the learning community. It also reveals that high school participants display notable interest in the engineering design process.Keywords: learning community, freshman design, high school I. INTRODUCTIONCollaborative learning and the use of a learning community has long been a goal of design curriculums. The National Science Foundation (NSF) has embraced these ideas with Division of Undergraduate Education (DUE) programs that encourage formation of learning communities and inter-institutional collaboration, such as collaboration between universities and K-12 schools. Pedagogical studies show that students simply learn more if they are actively involved in the learning process [1,2] and if they interact with other students [3]. Collaboration and interaction within a learning community are especially important in engineering design. Engineering design requires synthesis-a process that is greatly enhanced when students collaborate with others who have ideas different from their own.One common feature of traditional design courses is that they are taught with design teams comprised of students attending the same class and having similar educational backgrounds. Such courses do not teach students how to work on design teams where members may have significantly different technical backgrounds or may be located at different geographical locations. Collaboration with others from diverse backgrounds and locations is an important part of the learning process and common in "real-world" design practice. This is the problem specifically targeted in the learning community presented in this paper.Development of the learning community was funded by an NSF-CCLI Adaptation and Implementation grant [4,5]. It is based on an established freshman design curriculum described in [6] but adds a curriculum coordination component between the design class, a university graphics course and a high school technology course. The objective of this NSF project was to develop: (1) a pilot program that demonstrates how the learning community can be implemented; (2) several projects that can be used with this learning community; and (3) both direct and indirect assessment...

Measurements of NOx and CO in methane-fired, lean-premixed, high-pressure jet-stirred reactors (HP-JSRs) independently obtained by Rutar [1] and Rutar et al. [2] and by Bengtsson [3] and Bengtsson et al. [4] are well predicted assuming simple chemical reactor models and the GRI 3.0 chemical kinetic mechanism. The single-jet HP-JSR of Rutar [1] and Rutar et al. [2] is well modeled for NOx and CO assuming a single PSR for Damköhler number below 0.15. Under these conditions, the estimates of flame thickness indicate the flame zone, that is, the region of rapid oxidation and large concentrations of free radicals, fully fills the HP-JSR. For Damköhler number above 0.15, that is, for longer residence times, the NOx and CO are well modeled assuming two PSRs in series, representing a small flame zone followed by a large post-flame zone. The multi-jet reactor of Bengtsson [3] and Bengtsson et al. [4] is well modeled assuming a large PSR (over 88% of the reactor volume) followed by a short PFR, which accounts for the exit region of the HP-JSR and the short section of exhaust prior to the sampling point. The Damköhler number is estimated between 0.01 and 0.03. Our modeling shows the NOx formation pathway contributions. Although all pathways, including Zeldovich (under the influence of super-equilibrium O-atom), nitrous oxide, Fenimore prompt, and NNH, contribute to the total NOx predicted, of special note are the following findings: 1) NOx formed by the nitrous oxide pathway is significant throughout the conditions studied; and 2) NOx formed by the Fenimore prompt pathway is significant when the fuel-air equivalence ratio is greater than about 0.7 (as might occur in a piloted lean-premixed combustor) or when the residence time of the flame zone is very short. The latter effect is a consequence of the short lifetime of the CH radical in flames.

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NOx measurements in jet-stirred reactor (JSR) combustion of seven fuels are modelled using three complete chemical kinetic mechanisms. The two JSRs are operated at 1790 K, 1 atm, 2–4 ms, and the fuel-air equivalence ratio of 0.61. The modelled fuels are methanol, methane, ethane, ethene, propane, n-butane, and toluene. The experimental database also includes C1-C4 alkane mixtures, two light naphtas, four number two diesel oils, and benzene. The fuels and air are premixed, prevapourized, and preheated with a temperature-staged prevapourizer-premixer and an air-heater. Experiments show NOx and CO increase when burning fuels with increasing carbon-to-hydrogen ratio (from 0.25 to 0.88). The data are analysed using three complete chemical kinetic mechanisms: GRI 3.0 Mech., CNRS' C1-C4 hydrocarbon oxidation mechanism, and CNRS' toluene oxidation mechanism. The modelling shows that the increase in NOx with the fuel carbon-to-hydrogen ratio is because of the increase in the NO formation via NNH, Zeldovich, and nitrous oxide pathways. The NNH pathway produces between 25 and 45 per cent of the NO formed. GRI 3.0 Mech. tends to favour this pathway since it forms more O, H, and NNH reactive species than the CNRS' C1-C4 hydrocarbon mechanism. Several rate constants for NNH + O → NH + NO are considered and best agreement using two and three perfectly stirred reactor schemes is found with the rate constant k = 7 × 1013 cm3/mol/s.