Natural convection in attic-shaped spaces subject to sudden and ramp heating boundary conditions

In this study, a discussion of the fluid dynamics in the attic space is reported, focusing on its transient response to sudden and linear changes of temperature along the two inclined walls. The transient behaviour of an attic space is relevant to our daily life. The instantaneous and non-instantaneous (ramp) heating boundary condition is applied on the sloping walls of the attic space. A theoretical understanding of the transient behaviour of the flow in the enclosure is performed through scaling analysis. A proper identification of the timescales, the velocity and the thickness relevant to the flow that develops inside the cavity makes it possible to predict theoretically the basic flow features that will survive once the thermal flow in the enclosure reaches a steady state. A time scale for the heating-up of the whole cavity together with the heat transfer scales through the inclined walls has also been obtained through scaling analysis. All scales are verified by the numerical simulations.

Natural convection in attics subject to instantaneous and ramp cooling boundary conditions

A fundamental study of the fluid dynamics inside an attic shaped triangular enclosure with cold upper walls and adiabatic horizontal bottom wall is reported in this study. The transient behaviour of the attic fluid which is relevant to our daily life is examined based on a scaling analysis. The transient phenomenon begins with the instantaneous cooling and the cooling with linear decreases of temperature up to some specific time (ramp time) and then maintain constant of the upper sloped walls. It is shown that both inclined walls develop a thermal boundary layer whose thicknesses increase towards steady-state or quasi-steady values. A proper identification of the timescales, the velocity and the thickness relevant to the flow that develops inside the cavity makes it possible to predict theoretically the basic flow features that will survive once the thermal flow in the enclosure reaches a steady state. A time scale for the cooling-down of the whole cavity together with the heat transfer scales through the inclined walls has also been obtained through scaling analysis. All scales are verified by the numerical simulations.

Natural convection adjacent to an inclined flat plate and in an attic space under various thermal forcing conditions

The effect of viscous dissipation on natural convection from a vertical plate placed in a thermally stratified environment has been investigated numerically. The reduced equations are integrated by employing the implicit finite difference scheme or Ke1ler-box method and obtained the effect of heat due to viscous dissipation on the local skin-friction and loca1 Nusselt number at various stratification levels, for fluids having Prandtl number equals 10, 50, and 100. Solutions are also obtained using the perturbation technique for small values of viscous dissipation parameters and compared with the Finite Difference solutions. Effect of the heat transfer due to viscous dissipation and the temperature stratification are also shown on the velocity and temperature distributions in the boundary layer region. A numerical study of laminar doubly diffusive free convection flows adjacent to a vertical surface in a stable thermally stratified medium is also considered for this study. Solutions are obtained using the implicit Finite Difference method and compared with the local non-similarity method. The velocity and temperature distributions for different values of stratification parameter are shown graphically. The results show many interesting aspects of complex interaction of the two buoyant mechanisms.

The use of speech and lip modalities for robust speaker verification under adverse conditions

Investigates the use of lip information, in conjunction with speech information, for robust speaker verification in the presence of background noise. We have previously shown (Int. Conf. on Acoustics, Speech and Signal Proc., vol. 6, pp. 3693-3696, May 1998) that features extracted from a speaker's moving lips hold speaker dependencies which are complementary with speech features. We demonstrate that the fusion of lip and speech information allows for a highly robust speaker verification system which outperforms either subsystem individually. We present a new technique for determining the weighting to be applied to each modality so as to optimize the performance of the fused system. Given a correct weighting, lip information is shown to be highly effective for reducing the false acceptance and false rejection error rates in the presence of background noise

Funding and employment conditions : critical issues for Australian music therapy beyond 2009

As the Australian Journal of Music Therapy celebrates its 20th year of publication, it is evident that the profession of music therapy in Australia, has made substantial progress over these last 20 years. Jobs are regularly advertised on the website, there is a greater public awareness of what music therapy is, there are government recognised salary awards applicable in several states of the country, working conditions have generally improved, and many Australian music therapists are recognised on the international stage as leaders in their field of expertise. You can even go to a party and tell someone you are a music therapist and there is a good chance they will say 'oh yeah, I know someone who does that at the hospital / school / community centre / nursing home' instead of saying 'oh, so like, a what?'. Despite the impressive leaps and bounds that have been made, and the success of many programs in Australia to date, there is still a great deal of room for improvement. What are the critical issues ahead for the development of music therapy in Australia? In particular, how do music therapists develop going forward and secure funding for clinical initiatives? In reflecting on this question, this article identifies two key areas, amongst the many, that can be addressed by music therapists over the next 20 years: funding and employment conditions. Examples from the national early intervention music therapy program 'Sing and Grow' are used to illustrate the potential impact of addressing these two issues on the positive development of the profession into the future.

Bouncing back : the role of design in facilitating students to understand and deal with adversity

After state-wide flooding and a category-5 tropical cyclone, three-quarters of the state of Queensland was declared a disaster zone in early 2011. This deluge of adversity had a significant impact on university students, a few weeks prior to the start of the academic semester. The purpose of this paper is to examine the role that design plays in facilitating students to understand and respond to, adversity. The participants of this study were second and fourth year architectural design students at a large Australian University, in Queensland. As a part of their core architectural design studies, students were required to provide architectural responses to the recent catastrophic events in Queensland. Qualitative data was obtained through student surveys, work design work submitted by students and a survey of guests who attending an exhibition of the student work. The results of this research showed that the students produced more than just the required set of architectural drawings, process journals and models, but also recognition of the important role that the affective dimension of the flooding event and the design process played in helping them to both understand and respond to, adversity. They held the ‘real world’ experience and practical aspect of the assessment in higher regard than their typical focus on aesthetics and the making of iconic design. Perhaps most importantly, the students recognised that this process allowed them to have a voice, and a means to respond to adversity through the powerful language of design.

The effect of ocular surface conditions on blink rate and completeness

A healthy human would be expected to show periodic blinks, making a brief closure of the eyelids. Most blinks are spontaneous, occurring regularly with no external stimulus. However a reflex blink can occur in response to external stimuli such as a bright light, a sudden loud noise, or an object approaching toward the eyes. A voluntary or forced blink is another type of blink in which the person deliberately closes the eyes and the lower eyelid raises to meet the upper eyelid. A complete blink, in which the upper eyelid touches the lower eyelid, contributes to the health of ocular surface by providing a fresh layer of tears as well as maintaining optical integrity by providing a smooth tear film over the cornea. The rate of blinking and its completeness vary depending on the task undertaken during blink assessment, the direction of gaze, the emotional state of the subjects and the method under which the blink was measured. It is also well known that wearing contact lenses (both rigid and soft lenses) can induce significant changes in blink rate and completeness. It is been established that efficient blinking plays an important role in ocular surface health during contact lens wear and for improving contact lens performance and comfort. Inefficient blinking during contact lens wear may be related to a low blink rate or incomplete blinking and can often be a reason for dry eye symptoms or ocular surface staining. It has previously been shown that upward gaze can affect blink rate, causing it to become faster. In the first experiment, it was decided to expand on previous studies in this area by examining the effect of various gaze directions (i.e. upward gaze, primary gaze, downward gaze and lateral gaze) as well as head angle (recumbent position) on normal subjects’ blink rate and completeness through the use of filming with a high-speed camera. The results of this experiment showed that as the open palpebral aperture (and exposed ocular surface area) increased from downward gaze to upward gaze, the number of blinks significantly increased (p<0.04). Also, the size of closed palpebral aperture significantly increased from downward gaze to upward gaze (p<0.005). A weak positive correlation (R² = 0.18) between the blink rate and ocular surface area was found in this study. Also, it was found that the subjects showed 81% complete blinks, 19% incomplete blinks and 2% of twitch blinks in primary gaze, consistent with previous studies. The difference in the percentage of incomplete blinks between upward gaze and downward gaze was significant (p<0.004), showing more incomplete blinks in upward gaze. The findings of this experiment suggest that while blink rate becomes slower in downward gaze, the completeness of blinking is typically better, thereby potentially reducing the risk of tear instability. On the other hand, in upward gaze while the completeness of blinking becomes worse, this is potentially offset by increased blink frequency. In addition, blink rate and completeness were not affected by lateral gaze or head angle, possibly because these conditions have similar size of the open palpebral aperture compared with primary gaze. In the second experiment, an investigation into the changes in blink rate and completeness was carried out in primary gaze and downward gaze with soft and rigid contact lenses in unadapted wearers. Not surprisingly, rigid lens wear caused a significant increase in the blink rate in both primary (p<0.001) and downward gaze (p<0.02). After fitting rigid contact lenses, the closed palpebral aperture (blink completeness) did not show any changes but the open palpebral aperture showed a significant narrowing (p<0.04). This might occur from the subjects’ attempt to avoid interaction between the upper eyelid and the edge of the lens to minimize discomfort. After applying topical anaesthetic eye drops in the eye fitted with rigid lenses, the increased blink rate dropped to values similar to that before lens insertion and the open palpebral aperture returned to baseline values, suggesting that corneal and/or lid margin sensitivity was mediating the increased blink rate and narrowed palpebral aperture. We also investigated the changes in the blink rate and completeness with soft contact lenses including a soft sphere, double slab-off toric design and periballast toric design. Soft contact lenses did not cause any significant changes in the blink rate, closed palpebral aperture, open palpebral aperture and the percentage of incomplete blinks in either primary gaze or downward gaze. After applying anaesthetic eye drops, the blink rate reduced in both primary gaze and downward gaze, however this difference was not statistically significant. The size of the closed palpebral aperture and open palpebral aperture did not show any significant changes after applying anaesthetic eye drops. However it should be noted that the effects of rigid and soft contact lenses that we observed in these studies were only the immediate reaction to contact lenses and in the longer term, it is likely that these responses will vary as the eye adapts to the presence of the lenses.

Structural and thermal performance of cold-formed steel stud wall systems under fire conditions

Cold-formed steel stud walls are a major component of Light Steel Framing (LSF) building systems used in commercial, industrial and residential buildings. In the conventional LSF stud wall systems, thin steel studs are protected from fire by placing one or two layers of plasterboard on both sides with or without cavity insulation. However, there is very limited data about the structural and thermal performance of stud wall systems while past research showed contradicting results, for example, about the benefits of cavity insulation. This research was therefore conducted to improve the knowledge and understanding of the structural and thermal performance of cold-formed steel stud wall systems (both load bearing and non-load bearing) under fire conditions and to develop new improved stud wall systems including reliable and simple methods to predict their fire resistance rating. Full scale fire tests of cold-formed steel stud wall systems formed the basis of this research. This research proposed an innovative LSF stud wall system in which a composite panel made of two plasterboards with insulation between them was used to improve the fire rating. Hence fire tests included both conventional steel stud walls with and without the use of cavity insulation and the new composite panel system. A propane fired gas furnace was specially designed and constructed first. The furnace was designed to deliver heat in accordance with the standard time temperature curve as proposed by AS 1530.4 (SA, 2005). A compression loading frame capable of loading the individual studs of a full scale steel stud wall system was also designed and built for the load-bearing tests. Fire tests included comprehensive time-temperature measurements across the thickness and along the length of all the specimens using K type thermocouples. They also included the measurements of load-deformation characteristics of stud walls until failure. The first phase of fire tests included 15 small scale fire tests of gypsum plasterboards, and composite panels using different types of insulating material of varying thickness and density. Fire performance of single and multiple layers of gypsum plasterboards was assessed including the effect of interfaces between adjacent plasterboards on the thermal performance. Effects of insulations such as glass fibre, rock fibre and cellulose fibre were also determined while the tests provided important data relating to the temperature at which the fall off of external plasterboards occurred. In the second phase, nine small scale non-load bearing wall specimens were tested to investigate the thermal performance of conventional and innovative steel stud wall systems. Effects of single and multiple layers of plasterboards with and without vertical joints were investigated. The new composite panels were seen to offer greater thermal protection to the studs in comparison to the conventional panels. In the third phase of fire tests, nine full scale load bearing wall specimens were tested to study the thermal and structural performance of the load bearing wall assemblies. A full scale test was also conducted at ambient temperature. These tests showed that the use of cavity insulation led to inferior fire performance of walls, and provided good explanations and supporting research data to overcome the incorrect industry assumptions about cavity insulation. They demonstrated that the use of insulation externally in a composite panel enhanced the thermal and structural performance of stud walls and increased their fire resistance rating significantly. Hence this research recommends the use of the new composite panel system for cold-formed LSF walls. This research also included steady state tensile tests at ambient and elevated temperatures to address the lack of reliable mechanical properties for high grade cold-formed steels at elevated temperatures. Suitable predictive equations were developed for calculating the yield strength and elastic modulus at elevated temperatures. In summary, this research has developed comprehensive experimental thermal and structural performance data for both the conventional and the proposed non-load bearing and load bearing stud wall systems under fire conditions. Idealized hot flange temperature profiles have been developed for non-insulated, cavity insulated and externally insulated load bearing wall models along with suitable equations for predicting their failure times. A graphical method has also been proposed to predict the failure times (fire rating) of non-load bearing and load bearing walls under different load ratios. The results from this research are useful to both fire researchers and engineers working in this field. Most importantly, this research has significantly improved the knowledge and understanding of cold-formed LSF walls under fire conditions, and developed an innovative LSF wall system with increased fire rating. It has clearly demonstrated the detrimental effects of using cavity insulation, and has paved the way for Australian building industries to develop new wall panels with increased fire rating for commercial applications worldwide.

Facilitating student self-direction in a blended learning environment

Business postgraduate education is rapidly adopting virtual learning environments to facilitate the needs of a time-poor stakeholder community, where part-time students find it difficult to attend face-to-face classes. Creating engaged, flexible learning opportunities in the virtual world is therefore the current challenge for many business academics. However, in the blended learning environment there is also the added pressure of encouraging these students to develop soft managerial or generic skills such as self-reflection. The current paper provides an overview of an action-research activity exploring the experiences of students who were required to acquire the skills of self-reflection within a blended learning unit dominated by on-line learning delivery. We present the responses of students and the changes made to our teaching and learning activities to improve the facilitation of both our face-to-face delivery as well as the on-line learning environment.

Facilitating Malaysia towards innovative society : arguing the case for open access policy

The Malaysian National Innovation Model blueprint states that there is an urgent need to pursue an innovation-oriented economy to improve the nation’s capacity for knowledge, creativity and innovation. In nurturing a pervasive innovation culture, the Malaysian government has declared the year 2010 as an Innovative Year whereby creativity among its population is highly celebrated. However, while Malaysian citizens are encouraged to be creative and innovative, scientific data and information generated from publicly funded research in Malaysia is locked up because of rigid intellectual property licensing regimes and traditional publishing models. Reflecting on these circumstances, this paper looks at, and argue why, scientific data and information should be made available, accessible and re-useable freely to promote the grassroots level of innovation in Malaysia. Using innovation theory as its platform of argument, this paper calls for an open access policy for publicly funded research output to be adopted and implemented in Malaysia. Simultaneously, a normative analytic approach is used to determine the types of open access policy that ought to be adopted to spur greater innovation among Malaysians.

Flow regime transition criteria for two-phase flow at reduced gravity conditions

Flow regime transition criteria are of practical importance for two-phase flow analyses at reduced gravity conditions. Here, flow regime transition criteria which take the friction pressure loss effect into account were studied in detail. Criteria at reduced gravity conditions were developed by extending an existing model with various experimental datasets taken at microgravity conditions showed satisfactory agreement. Sample computations of the model were performed at various gravity conditions, such as 0.196, 1.62, 3.71, and 9.81 m/s2 corresponding to micro-gravity and lunar, Martian and Earth surface gravity, respectively. It was found that the effect of gravity on bubbly-slug and slug-annular (churn) transitions in a two-phase flow system was more pronounced at low liquid flow conditions, whereas the gravity effect could be ignored at high mixture volumetric flux conditions. While for the annular flow transitions due to flow reversal and onset of dropset entrainment, higher superficial gas velocity was obtained at higher gravity level.

Facilitating growth in prospective teachers’ knowledge : teaching geometry in primary schools

This paper reports on a study that focused on growth of understanding about teaching geometry by a group of prospective teachers engaged in lesson plan study within a computer-supported collaborative learning (CSCL) environment. Participation in the activity was found to facilitate considerable growth in the participants’ pedagogical-content knowledge (PCK). Factors that influenced growth in PCK included the nature of the lesson planning task, the cognitive scaffolds inserted into the CSCL virtual space, the meta-language scaffolds provided to the participants, and the provision of both private and public discourse spaces. The paper concludes with recommendations for enhancing effective knowledge-building discourse about mathematics PCK within prospective teacher education CSCL environments.