Student-based Assessment in a Multi-disciplinary Problem-based Learning Environment

Engineering education in Australia must respond to a changing environment so that the nation continues to produce engineering graduates able to contribute towards the development of society in the face of local, national and international pressures. To address these changes, engineering schools are introducing teaching initiatives aimed at developing a range of skills including people, problem-solving and self-directed learning skills. Many of these programs encourage student learning through active participation with the subject matter; however, they also place a considerable burden upon staff because of the assessment load required to ensure that students attain the required competencies. Student-based assessment strategies are often proposed as techniques for enhancing student learning by transferring the ownership and some of the responsibility for the assessment process to the student body. This paper examines the literature relating to student-based assessment and presents some assessment strategies suitable for a problem-based learning course in embedded systems design.     

Surface-Fluorinated Coatings

Fluoropolymers have many properties that are desirable in coatings. However, because of their poor solubility, formulating coatings containing fluoropolymers can be very difficult. Fluorine-based polymers that have been modified to increase their solubility have been used in a number of resin systems to bring the properties of fluoropolymers to the final coating. Typically these systems have fluorine throughout the entire resin and consequently have a high total fluorine level. We have found that by designing fluorinated molecules that stratify to the surface in the wet coating, we can deliver systems with the excellent surface properties of fluoropolymers but at very low total fluorine levels.     

Laboratory evaluation of anti‐fretting lubricants

To characterise the friction and wear behaviour of materials and lubricants under a variety of operating conditions, laboratory models are frequently used to provide useful information. For example, during the development and/or selection of tribomaterials and lubricants, laboratory ranking of candidate products can save many hours of field testing. A reciprocating ball‐on‐flat wear test rig has been developed to rank the performance of materials, surface coatings, and lubricants under boundary, extreme‐pressure, or fretting conditions in a variety of environments and at various temperatures. The rig design is based on ASTM G133–1995. The friction force and wear are measured on both specimens while the load, stroke length and frequency, test temperature, lubricant type, test duration, surface topography of both ball and flat specimens, specimen materials, and environmental conditions are noted. The results presented in this paper refer specifically to a series of tests performed to evaluate various anti‐fretting lubricants. Two lubricants are compared in terms of friction coefficient and wear volume over time. A clear difference is shown between the two products.     

Probiotic bacteria are antagonistic to Salmonella enterica and Campylobacter jejuni and influence host lymphocyte responses in human microbiota‐associated immunodeficient and immunocompetent mice

A defined human microbiota‐associated (HMA) mouse model in BALB/c and immunodeficient Tgε26 mice was used to assess the ability of probiotic lactobacilli and bifidobacteria to enhance colonization resistance to gastrointestinal (GI) tract pathogens. Probiotic bacteria (1×10⁸ colony forming unit (CFU)/mL) successfully excluded Campylobacter jejuni from both strains of mice 7 days after challenge. The probiotic bacteria also reduced the number of Salmonella in the large intestines of both mouse strains. The nylon wool fractionated spleen lymphocyte populations were incubated with Salmonella or C. jejuni antigens. The probiotic treatments did not affect lymphocyte proliferation to C. jejuni antigens, but significantly increased proliferation of lymphocytes to Salmonella antigens by 68 and 55%, respectively, over untreated mice. Caspase 3/7 activation was significantly reduced 33 and 38% in the T and B lymphocyte fractions, respectively, of probiotic‐treated, Salmonella‐challenged HMA BALB/c mice, suggesting that lymphocyte rescue from apoptosis was occurring as a result of probiotic bacteria activity. These results revealed an immunosuppressive activity by Salmonella that was inhibited by the presence of probiotic bacteria. In summary, lactobacilli and bifidobacteria competitively excluded C. jejuni from immunocompetent and immunodeficient mice and antagonized an observable Salmonella‐induced immunosuppression in immunocompetent mice.     

Field-deployable, high-resolution, time-of-flight aerosol mass spectrometer

The development of a new high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is reported. The high-resolution capabilities of this instrument allow the direct separation of most ions from inorganic and organic species at the same nominal m/z, the quantification of several types of organic fragments (CxHy, CxHyOz, CxHyNp, CxHyOzNp), and the direct identification of organic nitrogen and organosulfur content. This real-time instrument is field-deployable, and its high time resolution (0.5 Hz has been demonstrated) makes it well-suited for studies in which time resolution is critical, such as aircraft studies. The instrument has two ion optical modes: a single-reflection configuration offers higher sensitivity and lower resolving power (up to approximately 2100 at m/z 200), and a two-reflectron configuration yields higher resolving power (up to approximately 4300 at m/z 200) with lower sensitivity. The instrument also allows the determination of the size distributions of all ions. One-minute detection limits for submicrometer aerosol are <0.04 microg m(-3) for all species in the high-sensitivity mode and <0.4 microg m(-3) in the high-resolution mode. Examples of ambient aerosol data are presented from the SOAR-1 study in Riverside, CA, in which the spectra of ambient organic species are dominated by CxHy and CxHyOz fragments, and different organic and inorganic fragments at the same nominal m/z show different size distributions. Data are also presented from the MIRAGE C-130 aircraft study near Mexico City, showing high correlation with independent measurements of surrogate aerosol mass concentration.     

Nanotube-bridged wires with sub-10 nm gaps

We report a simple but efficient method to synthesize carbon nanotube-bridged wires (NBWs) with gaps as small as 5 nm. In this method, we have combined a strategy for assembling carbon nanotubes (CNTs) inside anodized aluminum oxide pores and the on-wire lithography technique to fabricate CNT-bridged wires with gap sizes deliberately tailored over the 5-600 nm range. As a proof-of-concept demonstration of the utility of this architecture, we have prepared NBW-based chemical and biosensors which exhibit higher analyte sensitivity (lower limits of detection) than those based on planar CNT networks. This observation is attributed to a greater surface-to-volume ratio of CNTs in the NBWs than those in the planar CNT devices. Because of the ease of synthesis and high yield of NBWs, this technique may enable the further incorporation of CNT-based architectures into various nanoelectronic and sensor platforms.     

To lump or to split? Comparing individuals with traumatic and nontraumatic limb loss in the first year after amputation.

Objective: To compare individuals with traumatic (TE) vs. nontraumatic (NTE) amputation etiology on pain, psychological, and social variables over the first 12 months postamputation, and to explore changes in mean levels of and correlations between these variables over time. Participants: There were 111 adults with newly acquired limb loss. Settings: A VA medical center and a Level I trauma hospital in a large metropolitan area. Main Outcome Measures: Characteristic Pain Severity, Pain Interference, Patient Health Questionnaire depression module, Posttraumatic Stress Disorder Checklist, Social Constraints Scale, Aversive Emotional Support Scale, Centers for Disease Control and Prevention single item Social Support measure, single item loneliness measure. Results: The NTE group was significantly older, had lower income, and had greater medical comorbidity, preamputation pain, and physical disability. The etiology groups did not differ significantly in mean levels of outcome variables except that the TE group reported greater aversive emotional support at 6 and 12 months. The TE group demonstrated a quadratic change in pain interference, with highest levels at 6 months and a linear increase in social constraints. Both etiology groups showed a linear increase in PTSD symptoms over time. Correlations between physical, psychological, and social distress were observed earlier in the year for the NTE group. Conclusion: Despite significant demographic and preamputation experience differences, few differences in outcomes emerged by etiology group in the first year after amputation. Findings suggest that the year after amputation may be a time of greater change for those with traumatic amputation compared to those with nontraumatic amputation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Consequence-based management of railroad bridge networks

To increase profitability, add capacity and comply with new federal regulations on bridge safety, North American railroads are exploring means to improve the management of their bridge networks. Current maintenance, repair and replacement (MRR) decisions are informed by bridge inspections and ratings, which recommend observing the response of bridges under trains. However, an objective relationship between bridge responses and the associated impact to railroad operations has yet to be established. If the consequences of MRR decisions could be better determined, then the railroads could more effectively allocate their limited resources. Chief bridge engineers from different Class I railroads provided the values of displacements and assessment used to develop this paper. Researchers monitored displacements from over 50 train crossing events and related them to decisions on operations and maintenance. This paper develops an approach for consequence-based management of bridge networks for making network MRR decisions, employing fragility curves to relate service condition limit states to transverse displacement. The operational costs associated with these service conditions can estimate the total costs of a given MRR policy. In this way, optimum MRR decisions can minimise the total network costs. This framework provides a consistent approach for the prioritisation of railroad bridge MRR decisions.     

Scientists’ perceptions of the social and political implications of their research

We explore an empirical approach to studying the social and political implications of science by gathering scientists’ perceptions of the social impacts of their research. It was found that 78 percent of surveyed scientists from a variety of fields responding to a survey indicated that the research performed in connection with a recent highly cited paper had such implications. Health related implications were the most common, but other types of implications encountered were technological spin-offs, public understanding, economic and policy benefits. Surprisingly many scientists considered the advancement of science itself to be a social implication of their research. The relations of these implications to the field and topics of research are examined, and a mapping of implications gives an overview of the major dimensions of the social impacts of science.