Logan City Council

Place value understanding requires the same activity that students use when developing fractional and algebraic reasoning, making this understanding foundational to mathematics learning. However, many students engage successfully in mathematics classrooms without having a conceptual understanding of place value, preventing them from accessing mathematics that is more sophisticated later. The purpose of this exploratory study is to investigate how upper elementary students' unit coordination related to difficulties they experience when engaging in place value tasks. Understanding place value requires that students coordinate units recursively to construct multi‐digit numbers from their single‐digit number understandings through forms of unit development and strategic counting. Findings suggest that students identified as low‐achieving were capable of only one or two levels of unit coordination. Furthermore, these students relied on inaccurate procedures to solve problems with millennial numbers. These findings indicate that upper elementary students identified as low‐achieving are not to yet able to (de)compose numbers effectively, regroup tens and hundreds when operating on numbers, and transition between millennial numbers. Implications of this study suggest that curricula designers and statewide standards should adopt nuances in unit coordination when developing tasks that promote or assess students' place value understanding.

This chapter discusses the influence of traffic and land use factors on atmospheric pollutants build-up, dry and wet deposition and build-up on urban surfaces. Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) were the focus of discussion in this chapter as these pollutants are ubiquitous in the urban environment, being commonly associated with traffic and anthropogenic activities common to urban areas and are toxic to human and ecosystem health. The research outcomes presented in this chapter confirm the influential role played by atmospheric pollution in stormwater pollution. The study outcomes also highlight the linkage between pollutants species with their potential sources and influential factors. Furthermore, the linkages between pollutants in the atmospheric phase, depositions and build-up on urban surfaces are also identified. For example, Zn was found to be the most abundant heavy metal element present in atmospheric build-up, atmospheric deposition and build-up on road surfaces, whilst light molecular weight PAHs have a higher concentration and spatial variability in both, atmospheric and road surface phases. The analysis also highlighted the influence exerted by heavy duty vehicle traffic on pollution in the urban environment, particularly in industrial land use areas. The knowledge created will contribute to informed decision making for minimising urban stormwater pollution and thereby safeguarding the urban water environment. In addition, these outcomes can also be applied in urban transport planning in order to enhance urban liveability.

Heavy metals build-up on urban road surfaces is a complex process and influenced by a diverse range of factors. Although numerous research studies have been conducted in the area of heavy metals build-up, limited research has been undertaken to rank these factors in terms of their influence on the build-up process. This results in limitations in the identification of the most critical factor/s for accurately estimating heavy metal loads and for designing effective stormwater treatment measures. The research study undertook an in-depth analysis of the factors which influence heavy metals build-up based on data generated from a number of different geographical locations around the world. Traffic volume was found to be the highest ranked factor in terms of influencing heavy metals build-up while land use was ranked the second. Proximity to arterial roads, antecedent dry days and road surface roughness has a relatively lower ranking. Furthermore, the study outcomes advances the conceptual understanding of heavy metals build-up based on the finding that with increasing traffic volume, total heavy metal build-up load increases while the variability decreases. The outcomes from this research study are expected to contribute to more accurate estimation of heavy metals build-up loads leading to more effective stormwater treatment design.