Electricity consumption, employment and real income in Australia evidence from multivariate Granger causality tests

This paper examines the relationship between electricity consumption, employment and real income in Australia within a cointegration and causality framework. We find that electricity consumption, employment and real income are cointegrated and that in the long-run employment and real income Granger cause electricity consumption, while in the short run there is weak unidirectional Granger causality running from income to electricity consumption and from income to employment.

Reconstructing the incidence of human immunodeficiency virus (HIV) in Hong Kong by using data from HIV positive tests and diagnoses of acquired immune deficiency syndrome

The human immunodeficiency virus–acquired immune deficiency syndrome (HIV–AIDS) epidemic in Hong Kong has been under surveillance in the form of voluntary reporting since 1984. However, there has been little discussion or research on the reconstruction of the HIV incidence curve. This paper is the first to use a modified back-projection method to estimate the incidence of HIV in Hong Kong on the basis of the number of positive HIV tests only. The model proposed has several advantages over the original back-projection method based on AIDS data only. First, not all HIV-infected individuals will develop AIDS by the time of analysis, but some of them may undertake an HIV test; therefore, the HIV data set contains more information than the AIDS data set. Second, the HIV diagnosis curve usually has a smoother pattern than the AIDS diagnosis curve, as it is not affected by redefinition of AIDS. Third, the time to positive HIV diagnosis is unlikely to be affected by treatment effects, as it is unlikely that an individual receives medication before the diagnosis of HIV. Fourth, the induction period from HIV infection to the first HIV positive test is usually shorter than the incubation period which is from HIV infection to diagnosis of AIDS. With a shorter induction period, more information becomes available for estimating the HIV incidence curve. Finally, this method requires the number of positive HIV diagnoses only, which is readily available from HIV–AIDS surveillance systems in many countries. It is estimated that, in Hong Kong, the cumulative number of HIV infections during the period 1979–2000 is about 2600, whereas an estimate based only on AIDS data seems to give an underestimate.

Processing and characterization of porous aluminum

Aluminum foams are now being introduced into automotive industry to reduce weight, to absorb energy in crash situations and to carry sound or heat absorbing functions. In the present study, a novel Spark Plasma Sintering (SPS) process for producing porous aluminums with controlled pore size and porosity and superior energy absorption has been developed. Experimental procedures included the mixing of starting powders, compacting, SPS sintering and leaching out of the space-holding particles. Porous aluminums with various porosities and a wide range of pore size distributions can be produced by the SPS process. Optical microscopy, scanning electron microscopy (SEM) and quantitative image analyses were used to characterize the porous aluminums. Compressive tests were carried out on the aluminum foams to evaluate the mechanical properties.

Strain rate effects on the energy absorption of rapidly manufactured composite tubes

Quasi-static and intermediate rate axial crush tests were conducted on tubular specimens of Carbon/Epoxy (Toray T700/G83C) and Glass/Polypropylene (Twintex). The quasi-static tests were conducted at 10 mm/min (1.67 x 10¯⁴ m/s); five different crush initiators were used. Tests at intermediate rates were performed at speeds of 0.25, 0.5, 0.75, 1, 2, and 4m/s. Modes of failure and specific energy absorption (SEA) values were studied. The highest SEA measured was 86 kJ/kg. This value was observed using Carbon/Epoxy samples at quasi static rates with a 45° chamfer initiator. The highest energy absorption for Twintex tubes was observed to be 57.56 kJ/kg during 45° chamfer initiated tests at 0.25 m/s. Compared with steel and aluminium, SEA values of 15 and 30 kJ/kg, respectively, the benefits of using composite materials in crash structures become apparent.

Many-sample location and scale tests with quantile-function error distributions /by Azmeri Khan

This thesis, using a computer simulation, studies the effect of the normal distribution assumption on the power of several many-sample location and scale test procedures. It also suggests an almost robust parametric test, namely numerical likelihood ratio test (NLRT) for non-normal situations. The NLRT is found better than all of the tests considered. Some real life data sets were used as examples.

Crash investigation of side intrusion beam during high and low pressure tube hydroforming

Advanced high strength steels (AHSS), in particular, are an attractive group materials, offering higher strength for improved energy absorption and the opportunity to reduce weight through the use of thinner gauges. High pressure tube hydroforming (HPTH) has been used to produce safety components for these steels, but it is expensive. Low pressure tube hydroforming (LPTH) is a lower cost alternative to form the safety components in the car. The side intrusion beam is the second most critical part after front rail in the car structure for passenger safety during crash. The forming as well as crash behaviour of a square side intrusion beam from both processes was investigated using numerical simulation. This paper investigated the interaction between the forming and crash response of these materials in order to evaluate their potential for use in vehicle design for crashworthiness. The energy absorption characteristics of the different tubes were calculated and the results from the numerical analyses compared for both hydroforming process.

Crash landing at INSEAD : initiating a grounded theory of the pedagogical effectiveness of simulation games for teaching aspects of entrepreneurship

A practical teaching difficulty arising in a conducive environment provided opportunity to turn the particular problem into a case study with generic implications. Little research has been conducted on the use or effectiveness of simulation games for teaching entrepreneurship. In the context of established literature critiquing the effectiveness of simulation games as teaching devices in managerial contexts and at a point where problems in using a simulation game as part of entrepreneurship course became evident, the authors designed and executed a single-case research project to generate initial theoretical propositions about the pedagogical effectiveness of simulation games for teaching various concepts and aspects of entrepreneurship. The case analysed the perceived learning environment created when the Sky-High simulation was played by 41 MBA students taking an elective entrepreneurship course at INSEAD. The research design embodied the established methodological principles specified by Yin (1989), for effective case research. Theory building was based upon the grounded-theorizing procedures articulated by Glaser and Strauss (1967). Analysis and synthesis produced a grounded theory, in the form of a normative argument, containing four attribute categories and associated properties required of a simulation game to make it an efficacious teaching device in entrepreneurship contexts. The establishment of this grounded theory has made it both desirable and feasible to contemplate creation of an ISO quality standard for educational simulation games.

CAE crash analysis of structures in oblique loading

This work focussed on how tubular steel structures similar to that in frontal car frames deform under crash conditions. The novelty comes from finding three crash modes: axial crush, transitional and global bending. Each mode was categorised by reaction force and energy absorption, this allowing for better structural design practices.

The reliability of two visual motor integration tests used with health adults

Occupational therapists often assess the visual motor integration (VMI) skills of children, adults, and the elderly, which are parts of the Body Functions and Structures of the International Classification of Functioning, Disability and Health. Objective. As it is imperative that therapists use tests and measures with strong psychometric properties, this study aims to examine the reliability of two VMI tests used with adults. Method. Sixty-one healthy adults, 18 males and 43 females, with an average age of 31.82 years, completed the Developmental Test of Visual Motor Integration (DTVMI) and the Full Range Test of Visual Motor Integration (FRTVMI). The Cronbach's alpha coefficient was used to examine the tests’ internal consistency, while the Spearman's rho correlation was used to evaluate the test–retest reliability, intrarater reliability, and interrater reliability of the two VMI tests. Results. The Cronbach's alpha coefficient for the DTVMI and FRTVMI was 0.66 and 0.80, respectively. The test–retest reliability coefficient was 0.77 (p < .001) for the DTVMI and 0.61 (p < .001) for the FRTVMI. The interrater reliability correlation was significant for both DTVMI at 0.79 (p < .001) and FRTVMI at 0.80 (p < .001). The DTVMI intrarater reliability correlation result was 0.95 (p < .001) and the FRTVMI at 0.87 (p < .001). Conclusion. Overall, the DTVMI and the FRTVMI exhibited moderate to high levels of reliability when used with a sample of healthy adults. Both VMI tests appear to exhibit reasonable levels of reliability and are recommended for use with adults and the elderly.

High strain rate tensile properties of rapidly cured woven carbon fibre composites

Tensile tests at high speeds corresponding to automotive crash events were conducted to understand the dynamic properties of rapidly cured woven carbon fiber composites. The High Strain Rate (HSR) experiments were conducted on a servo-hydraulic machine at constant velocities up to a maximum of 25 m/s (82 ft/s). Results from HSR tests were compared with the static results to determine the rate sensitivity of the composite. A high speed camera was used to capture the failure at HSR. The tensile properties of rapidly cured laminate were compared to oven cured laminate to justify its productivity while maintaining the desired properties. The methodology used to achieve constant velocity during HSR tests is discussed in detail. The specimen geometry was specially designed to suit the test rig and to achieve high speeds during tests. All the specimens failed with linear elasticity until sudden brittle fracture. The Scanning Electron Microscopy (SEM) images of the fracture zone were used to identify the failure modes observed at static and high strain rates.

Modelling the side impact of carbon fiber tubes

Metallic tubes have been extensively studied for their crashworthiness as they closely resemble automotive crash rails. Recently, the demand to improve fuel economy and reduce vehicle emissions has led automobile manufacturers to explore the crash properties of light weight materials such as fibre reinforced polymer composites, metallic foams and sandwich structures in order to use them as crash barriers. This paper discusses the response of carbon fibre reinforced polymer (CFRP) tubes and their failure mechanisms during side impact. The energy absorption of CFRP tubes is compared to similar Aluminium tubes. The response of the CFRP tubes during impact was modelled using Abaqus finite element software with a composite fabric material model. The material inputs were given based on standard tension and compression test results and the in-plane damage was defined based on cyclic shear tests. The failure modes and energy absorption observed during the tests were well represented by the finite element model.

The indentation behaviour of carbon fibre composite tubes-experiments & modelling

Metallic tubes have been extensively studied for their crashworthiness as they closely resemble automotive crash rails. Recently, the demand to produce lighter weight, yet safer vehicles has led to the need to understand the crash behaviour of novel materials, such as fibre reinforced polymer composites, metallic foams and sandwich structures. This paper discusses the static indentation response of Carbon Fibre Reinforced Polymer (CFRP) tubes. The side impact on a CFRP tube involves various failure mechanisms. This paper highlights these mechanisms and compares the energy absorption of CFRP tubes with similar Aluminium tubes. The response of the CFRP tubes during bending was modelled using ABAQUS finite element software with a composite fabric material model. The material inputs were given based on standard tension and compression test results and the in-plane damage was defined based on cyclic shear tests. The failure modes and energy absorption observed during the tests were well represented by the finite element model.

Convergent validity of two visual motor integration tests

Background: Occupational therapists often assess visual motor integration (VMI) skills. It is, therefore, imperative that therapists use VMI tests with robust measurement properties.

Objective: This study examined the convergent validity of two VMI tests used to assess children, adolescents and adults.

Method: Three groups of healthy participants (n = 153) completed the Beery-Buktenica Developmental Test of Visual-Motor Integration (DTVMI) and the Full Range Test of Visual Motor Integration (FRTVMI). Seventy-three children aged 5-10 years (37 males and 36 females; mean age 7.5 years, SD = 2.20), 19 adolescents aged 11-17 years (8 males and 11 females; 13.1 years, SD = 2.16), and 61 adults (18 males and 43 females; mean age 31.82 years, SD = 11.20) completed the DTVMI and the FRTVMI. Spearman rho correlation coefficients were used to investigate whether each pair of the VMI test scores for each of the three participant age groups were associated.

Results: The Spearman rho correlation coefficients between all three versions of the DTVMI and FRTVMI were statistically significant. For the child group, the correlation coefficient was rho = 0.70 (p<0.000), while the correlation between the VMI scores obtained by the adolescent group on the two tests was rho = 0.77 (p<0.000). For the adult participant group, the correlation coefficient between the DTVMI and the FRTVMI was rho = 0.70 (p<0.000).

Conclusion: The VMI scores obtained by the three participant age groups on the DTVMI and the FRTVMI were all significantly correlated with each other. Overall, the DTVMI and the FRTVMI exhibited large levels of convergent validity with each other, indicating that the two tests appear to measure similar visual-motor integration constructs.

The reliability of two visual motor integration tests used with children

Occupational therapists often assess the visual motor integration (VMI) skills of children and young people. It is important that therapists use tools with strong psychometric properties. This study aims to examine the reliability of 2 VMI tests. Ninety-two children between the ages of 5 and 17 years (response rate of 31%) completed 2 VMI tests: the Developmental Test of Visual Motor Integration (DTVMI) and the Full Range Test of Visual Motor Integration (FRTVMI). Cronbach's alpha coefficient was used to examine the internal consistency of the 2 VMI tests whereas Spearman's rho correlation was used to evaluate the test–retest reliability, intrarater reliability, and interrater reliability of the 2 VMI tests. The Cronbach's alpha coefficient for the DTVMI was .82 and .72 for the FRTVMI. The test–retest reliability coefficient was .73 (p = .000) for the DTVMI and .49 (p = .05) for the FRTVMI. The interrater correlation was significant for both the DTVMI at .94 (p = .000) and FRTVMI at .68 (p = .001). The DTVMI intrarater reliability correlation result was .90 (p = .000) and the FRTVMI at .85 (p = .000). Overall, the DTVMI exhibited a higher level of reliability than the FRTVMI. Both VMI tests appear to exhibit reasonable levels of reliability and are recommended for use with children and young people.