112 resultados para Greenhouse position

em Deakin Research Online - Australia


Relevância:

20.00% 20.00%

Publicador:

Resumo:

International pressure to reduce greenhouse gas emissions has forced many countries to look beyond 'demand side' measures. Several industry sectors are examining indirect requirements for energy and other resources that involve significant greenhouse gas emissions. The operation of buildings is responsible for approximately one quarter of greenhouse gas emissions in Australia. Moreover, he construction process consumes vast quantities of raw materials and complex goods and services each year. Each of the processes required for the provision of these products requires energy, and most of this is fossil fuel based. A national model of greenhouse gas emissions is required for residential building construction, to indicate where emissions reduction strategies should focus. A disaggregated input-output model is developed for the Australian residential building construction sector, and recommendations are made about how this model can be used in the development of policies of emissions mitigation for both the sector and individual residential buildings.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper aims to consider the embodied energy of building materials in the context of greenhouse gas emission mitigation strategies. Previous practice and research are highlighted where they have the potential to influence design decisions. Latest embodied energy figures are indicated, and the implications of applying these figures to whole buildings are discussed. Several practical examples are given to aid building designers in the selection of building materials for reduced overall life cycle greenhouse gas emissions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

It is commonly assumed that solar hot water systems save energy and reduce greenhouse emissions relative to conventional fossil fuel-powered systems. Very rarely has the life-cycle greenhouse emissions (including the embodied greenhouse emissions of manufacture) of solar hot water systems been analysed. The extent to which solar hot water systems can reduce emissions compared with conventional systems can be shown through a comparative life-cycle greenhouse emissions analysis. This method determined the time it takes for these net greenhouse emissions savings to occur, or the 'emissions payback period'. This paper presents the results of a life-cycle greenhouse emissions analysis of solar hot water systems in comparison with conventional hot water systems for a southern (Melbourne) and a northern (Brisbane) Australian city.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A series of laboratory experiments were carried out to investigate the response of a bar-blocked, saltwedge estuary to the imposition of both steady freshwater inflows and transient inflows that simulate storm events in the catchment area or the regular water releases from upstream reservoirs. The trapped salt water forms a wedge within the estuary, which migrates downstream under the influence of the freshwater inflow. The experiments show that the wedge migration occurs in two stages, namely (i) an initial phase characterized by intense shear-induced mixing at the nose of the wedge, followed by (ii) a relatively quiescent phase with significantly reduced mixing in which the wedge migrates more slowly downstream.

Provided that the transition time tT between these two regimes satisfies tT>g′h4L/q3α, as was the case for all our experiments and is likely to be the case for most estuaries, then the transition occurs at time tT=1.2(gα3L6/g′3q2)1/6, where g′=gΔρ/ρ0 is the reduced gravity, g the acceleration due to gravity, Δρ the density excess of the saline water over the density ρ0 of the freshwater, q the river inflow rate per unit width, and L and α are the length and bottom slope of the estuary, respectively.

A simple model, based on conversion of the kinetic energy of the freshwater inflow into potential energy to mix the salt layer, was developed to predict the displacement xw over time t of the saltwedge nose from its initial position. For continuous inflows subject to t<tT, the model predicts the saltwedge displacement as xw/h=1.1 (t/τ)1/3, where the normalizing length and time scales are h=(q2/g)1/3 and τ=g′α2h4L/q3, respectively. For continuous inflows subject to t>tT, the model predicts the displacement as xw/h=0.45N1/6(t/τ)1/6/α, where N=q2/g′h2L is a non-dimensional number for the problem. This model shows very good agreement with the experiments. For repeated, pulsed discharges subject to t<tT, the saltwedge displacement is given by (xw/h)3−(x0/h)(xw/h)2=1.3t/τ, where x0 is the initial displacement following one discharge event but prior to the next event. For pulsed discharges subject to t>tT, the displacement is given by (xw/h)6−(x0/h)(xw/h)5=0.008N(t/τ)/α6. This model shows very good agreement with the experiments for the initial discharge event but does systematically underestimate the wedge position for the subsequent pulses. However, the positional error is less than 15%.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This article presents a simple and reliable method for controlling the relative orientation between the two magnetic fields of a permanent magnet synchronous motor. Finding the initial (at motor powering- up time) value of this relative location is essential for the proper operation of the motor. After showing the system controllability, the utilized feedback control loop finds this initial relative orientation quickly and accurately. Further, using the proposed method allows considerable cost saving, as a transducer that is usually used for this purpose can be eliminated. The cost saving is most obvious in the case of linear motors and angle motors with large diameters. The way the problem is posed is an essential part of this work, and it is the reason behind the apparent simplicity of the solution. The method proposed relies on a single sensor, and it was tested when a relative encoder was used.


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Australian community sporting organisations have been relatively underresearched within the wider study of voluntary associations, yet their membership base is large and constitutes a sizable proportion of the population. This paper analyses data from the Australian Survey of Social Attitudes (AuSSA) 2003 (Gibson et al. 2004), initially to describe characteristics ofmembers ofcommunity sporting organisations in Australia (n=948). It goes on to compare attitudinal dimensions between members of sporting and other major third-sector organisations. On the basis of these comparisons three groupings of associations are suggested: social change, individual/social progress and individual/social maintenance. Sporting organisations form part of the latter category, and the paper briefly discusses the likely nature of social capital production associated with each.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this paper I intend to argue that biological science education and environmental education have traditionally represented fundamentally different discourses - that they have explicitly or implicitly adopted different epistemologies and ontologies - and that this difference has had implications for the conduct of research in these fields. I will draw on recent developments in theory, policy and practice in the field of environmental education to argue that this field tends to be located within a social discourse - that there is a foundation in policy and practice for considering environmental issues as fundamentally social and ethical in nature, rather than in some sense objectively existing. I then consider a rising topic in biology education (that of Biotechnology) as one which while tending to be treated within a scientific discourse, would be more fully explored educationally within a social discourse. I conclude by suggesting that in biology education research we need to consider a reconciliation of these historically differing perspectives.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Despite the continuing need for an empirically validated classification of marketing positions, for theoretical and practical purposes, it appears that no such schema exists. This study contributes to the development of such a taxonomy through an empirical examination of marketing positions. Specifically, the research extends an existing taxonomy by empirically investigating personal selling marketing activities. Based on the taxonomy developed by Darmon (1998), data were collected about the information load, information complexity, and time and relationship management activities of marketers. Various analytical techniques were used to investigate specific features of the instrument and the taxonomy, as well as to provide convergence for the conclusions drawn by the researchers. It was established that sales positions can be more meaningfully identified, and, therefore, better categorised, by six dimensions than by job title or job role. Further, it appears that marketers in the same selling position vary significantly on these dimensions. These findings have important implications for marketing theory, applied research and management. However, future research should refine the instrument used in this study, since some anomalies emerged in the findings, and extend the study by investigating a wider range of marketing positions. Such research may also explore whether the dimensions identified in this study influence the performance and job satisfaction of marketers, and the extent to which marketing managers account for these variations.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Concern about the growth of greenhouse gas emissions in Victoria has prompted the introduction of legislation to improve the thermal performance of the residential building envelope. Unfortunately, the size of the house is not considered in the rating tool that underpins the legislation. The energy embodied in the constructional materials is also not considered although it too is directly related to the size of the house. Another intrinsic factor relating residential housing energy and greenhouse gas emissions is the location of the residence and the travel preferences of the homeowner. The relationship between the operational, embodied and travel energy associated with a typical residential scenario in Melbourne over the last 50 years is examined in this paper. The analysis found that by the year 2000, the energy associated with work-related travel (44%) now exceeds the operational energy (37%). In terms of greenhouse gas emissions, the contribution from travel energy is almost double that from operational energy (28%).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Personal greenhouse gas calculators (PGGC) are important tools to raise awareness of the impact of personal behaviour on carbon dioxide emissions. Per capita, Australians are the highest emitters of greenhouse gases in the world and the task for them to reduce emissions to sustainable levels will be particularly challenging. This paper reviews six PGGC promoted in Australia and evaluates them for their consistency. The emissions for an individual currently practicing a modest green lifestyle are calculated and compared. Emission calculations were found to differ by an order of magnitude in some cases. It was also found that users of PGGC are not adequately informed about the limitations of the calculators. The adoption of modest and radical green lifestyles reduced greenhouse gas emissions to 83% and 53% of the average Australian, indicating that behavioural changes by consumers alone will be insufficient to reduce emissions to sustainable levels.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this paper we examine the problem of finding an optimal position for a receiver node in a single-hop sensor network. The basic idea is to minimize the network energy consumption according to a particular network cost function. Our contribution is to simply show the effect of signal path loss rates and sensor weighting on the optimal receiver position.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Many adolescents have diets that are less than optimal, particularly adolescents of low socioeconomic position (SEP). The determinants of SEP differences in adolescent dietary intake are poorly understood. This study examined the home food environments of adolescents and specifically investigated whether low SEP adolescents have less supportive home local environments, fewer eating rules and poorer home availability of fruit and vegetables than adolescents of high SEP. A cross-sectional, self-reported survey was administered to 3,264 adolescents in years 7 and 9, from 37 secondary schools in Victoria, Australia. Adolescent perceptions of the home meal environment, eating rules and home food availability were described and compared across SEP, which was measured using maternal education. Maternal education was linked to various aspects of the home meal environment, as well as home food availability, but not to eating rules. Low SEP adolescents were more likely to report that they were always allowed to watch television during meal times, and that unhealthy foods were always or usually available at home. In contrast, high SEP adolescents were more likely to report that vegetables were always served at dinner, that the evening meal was never an unpleasant time and always or usually a time for family connectedness, and that fruit was always or usually available at home. This study highlights aspects of the home food environment that might explain SEP variation in adolescent diets. Feasible ways of increasing home availability of healthy foods, and encouraging home meal environments to be supportive of healthy eating should be explored, particularly in households of low SEP adolescents.