Integrated comparative validation tests as an aid for building simulation tool users and developers

Published validation tests developed within major research projects have been an invaluable aid to program developers to check on their programs. This paper sets out how selected ASHRAE Standard 140-2004 and European CEN standards validation tests have been incorporated into the ESP-r simulation program so that they can be easily run by users and also discusses some of the issues associated with compliance checking. Embedding the tests within a simulation program allows program developers to check routinely whether updates to the simulation program have led to significant changes in predictions and to run sensitivity tests to check on the impact of alternative algorithms. Importantly, it also allows other users to undertake the tests to check that their installation is correct and to give them, and their clients, confidence in results. This paper also argues that validation tests should characterize some of the significant heat transfer processes (particularly internal surface convection) in greater detail in order to reduce the acceptance bands for program predictions. This approach is preferred to one in which validation tests are overly prescriptive (e.g., specifying fixed internal convection coefficients), as these do not reflect how programs are used in practice

Influence of virtual reality training on the roadside crossing judgements of child pedestrians

The roadside crossing judgments of children aged 7, 9, and 11 years were assessed relative to controls before and after training with a computer-simulated traffic environment. Trained children crossed more quickly, and their estimated crossing times became better aligned with actual crossing times. They crossed more promptly, missed fewer safe opportunities to cross, accepted smaller traffic gaps without increasing the number of risky crossings, and showed better conceptual understanding of the factors to be considered when making crossing judgments. All age groups improved to the same extent, and there was no deterioration when children were retested 8 months later. The results are discussed in relation to theoretical arguments concerning the extent to which children's pedestrian judgments are amenable to training

TAKE-OFF CHARACTERISTICS OF DOUBLE BACK SOMERSAULTS ON THE FLOOR

Backward take-offs are one of the most important and frequently used components of a floor routine in artistic gymnastics and usually occur at the beginning, middle, and at the finish of a routine. They also initiate the linear and rotational impulses for multiple somersaults with various body positions with or without twists. This study was undertaken to supplement the work done previously by Brueggemann (1983, 1987, 1994), Hwang et al. (1990) and Knoll(1993). The purpose of the study specifically, was to investigate the biomechanical characteristics of dynamic take-offs in double backward somersaults performed by ten male and eight female gymnasts on the floor at the world gymnastics championships in Brisbane, 1994. Data was captured at 50Hzby two video cameras; this permitted the calculation of 3D kinematic data. Mean and standard deviations of selected kinematic and temporal parameters were calculated in order to: compare differences of biomechanical characteristics between male and female gymnasts, identify the differences in take-offs between the different types of double back somersaults performed, and to compare the data to those reported previously. Analysis of the data for both male and female gymnasts revealed, that the most important performance factor determining somersault height, the vertical velocity of the CM, changed from 1.17±0.46 and2.35±0.60 m/s at touch-down to 4.2±0.46 and 3.54±0.85 m/s at take-off, respectively. The vertical velocity value for the male gymnasts (4.2k0.46 m/s)was lower, assuming their body mass is the same, compared to those of previously reported studies by Brueggemann 4.57 m/s (1983), Hwang et al. 4.46m/s (1990) and Newton et al. 5.8 m/s (1992). This was most likely due to localized leg muscle fatigue; 70% of the analyzed take-offs in this study were performed at the finishing acrobatic series of their floor exercise. Brueggemann(1983, 1987) and Hwang et al. (1990) reported, that the leg muscles played the dominant role in take-offs. The horizontal velocity at touch-down was 4.32 ±0.47and 4.05±0.47 m/s and decreased to 3.21±0.49 and 2.30±2.27 m/s at take-off, respectively. The take off period was 130 and 120 ms, respectively for males and females. The touch-down and take-off angles of the CM to ground contact and the horizontal was 64.1±6.1, 69.7±5.9 and 88.1±3 .0 and 90.6±5.0,respectively. Preliminary results from the angular momentum calculations confirm the values of previously reported studies by the above authors

LANDING ChARACTERISTICS OF DOUBLE BACK SOMERSAULTS ON THE FLOOR

One of the most frequently used components of a floor exercise are the landings which occur at the beginning, anywhere in between, and at the finish of the exercise. This study examined the biomechanical characteristics of double back somersault landings at the beginning, during, and at the end of a floor exercise. Performances of ten selected male gymnasts at the World Gymnastic Championships 1994 in Brisbane, were chosen. Kinematic data was captured at50 Hz through 3-D videorecordings during competitions, with the videocameras positioned on the catwalks above the floor of the competition venue. The analysis included mean and standard deviations of selected kinematic and temporal parameters in order to identify the biomechanical characteristics in landings, and to establish a profile for stable competition landings on floor, which should also comply with specific competition guidelines as set out by the FIG code of points. Analysis of the data revealed, that the displacement h m maximum CM height before the landing (2.18 ±0.16 m) to CM height at landing (0.88±0.13 m) was 1.3 ±0.1 1 m. The vertical and horizontal impact velocities were 4.2±0.46 and 3.21±0.49 m/s. The mean knee angles at landing (touch-down) were 153" and at minimum CM height were 98", a 55"knee angular landing force absorption over 0.12 sec. landing phase duration. The videorecordings of the individual landing performances were carefully reviewed to qualitatively investigate the completion of the second salto of the double back somersault before the landing. The better performances showed a reasonable extension of the body or a kick out before the landing, and the landing was actively anticipated through proper feet placement. Poor performances resulted in a slow second salto extending the hip and knee joints hurriedly into the landing surface. The mean angles between CM to toe and the horizontal at landing (touch-down) were 69". The mean angles between trunk and the horizontal and thigh to the horizontal at landing (touch-down) were 22and 84", respectively. Selected parameters of the results presented in this study may be used to form a representative biomechanical profile for floor landings

TAKE-OFF KINEMATICS OF BEAM DISMOUNTS

Beam dismounts require great courage, the highest level of precision of movement, and a special take-off technique. They have only marginally increased in difficulty in recent years, however, their technical execution has reached close to technical perfection. The technical criteria for the execution of successful beam dismounts are essentially similar to those of floor take-offs. Nevertheless, the configurations of the beam, its small width (10cm) and surface stiffness relative to the floor, put considerable limitations on the performer and subsequently change the take-off technique somewhat greatly. The purpose of the study was to investigate the biomechanical characteristics of dynamic beam dismounts performed by eight female gymnasts at the World Gymnastics Championships in Brisbane, 1994. Data was captured at 50 Hz by two video cameras positioned on the catwalks above the floor of the competition venue, which permitted the calculation of 3D kinematic data. Mean and standard deviations of selected kinematic and temporal parameters were calculated in order to: identify special biomechanical characteristics of takeoff technique for the balance beam, identify the differences in take-offs between the different types of dismounts performed, and to compare the data to those reported previously. Analysis of the data revealed, that the most important performance factor determining somersault height, the vertical velocity at take-off of the CM, ranged from 1.84 to 3.04 m/s, with a mean value of 2.49 ±0.40 m/s, which is considerably lower then for floor take-offs. The mean values for the horizontal velocity at take-off were 1.5

BIOMECHANICAL ANALYSIS OF THE "O'NEIL"

Paul O'Neil was the first gymnast to perform the "stretched double felge backward to forward swing in hang on the rings" at the World Gymnastic Championships in Brisbane,l994. This skill can be placed in the movement category (Brueggemann, 1994) of (backward) rotations in the vertical plane with a flexible horizontal axis of rotation. The O'Neil is listed in the current FIG code of points as a D-part in the difficulty category. The purpose of this case study is to provide a descriptive kinematic analysis and a description of the technique employed by O'Neil performing the "O'Neil". This dynamic skill is initiated by generating rotational kinetic energy during the downward swing phase from a momentary handstand position. Thus the angular velocity of the body in the sagittal plane is maximized simultaneously with the maximisation of the moment of inertia relative to the body's centre of gravity. The maximum vertical velocity during the downswing phase before the beginning of the O'Neil was -4.2 1 m/s and reached a value of 3.91 m/s 0.24 seconds after the beginning of the up-swing. Ludwig (1992) suggests that the rotation of the trunk around an axis through both shoulder joints becomes the most important determining factor for the swing on the rings. The data revealed, that during the up-swing the hip joint reached its lowest value (flexion) distinctly in advance of the shoulder joints. Once the arm-trunk (shoulder) angle reached its minimum value, the hip joint reached hyper extension throughout the skill. Also, the arms and shoulders remained under the rings, which was consistent with the findings of Nissinen (1983). The CG displacement at the beginning of the skill, the start of the upswing to its highest value was 1.75 m. The analysis of the joint angle movements provides an inside into the mechanism for increasing rotation. The angular velocity over time of the hip angle was -949&g/sec and for the shoulder angle was -670 &g/sec. The p o w d closing ofthe arm-trunk angle is the most important technical component for thesuccessful performance of the O'Neil. The duration of the skill was 1.46 sec from the beginning of the upward swing to the vertical body position at completion of the skill. It seems, that only O'Neil, who has that natural" anthropometric make-up", is able to perform such an exciting, unique, and novel skill

LANDING KINEMATICS OF HORIZONTAL BAR DISMOUNTS

Dismounts from the horizontal bar require the dissipation of substantial velocities and therefore large forces. The maximum heights from dismounts are seen to be in the order of 4m or more. Kerwin et al. (1990) reported that maximum heights for double somersault dismounts -ranged from 3.45 to 3.73m,and for triple somersault dismounts, 3.89 to 4.08m. The purpose of this study was to investigate the biomechanical characteristics of succesful horizontal bar landings. Performances of six out of eight male finalists from the individual apparatus finals on horizontal bar at the World Gymnastic Championships1994, Brisbane, were chosen. The dismounts were recorded at 50 Hz during competitions, with the video cameras positioned on the catwalks above the floor of the competition venue. The analysis included mean and standard deviations of selected kinematic and temporal parameters in order to identify successful competition landing techniques. The recordings of the individual dismounts and subsequent landing performances were reviewed to qualitatively investigate the completion of the last salto of the double and triple back somersaults before the landing. The double back layout dismounts showed aback arched shape for most of the flight phase before re-piking in preparation for the landing. Analysis of the data revealed a mean maximum CM height during dismount, before the landing, of 3.06 m and an impact velocity at landing of-6.48 d s . Brueggemann et al. (1994), reported mean release velocities of 4.79 st 0.33 m/s for double tucked back somersault, 4.04 f 0.1 m/s for double layout back somersault, and 5.08 f 0.31 d s for triple tucked back somersault dismounts, which compares to the impact velocity of this study. The knee angle at landing was 156" and minimum knee angle during landing was 87". This available range of motion of 69" knee flexion with a landing phase duration of 0.14sec7 was a significant factor for the preparation phase of successful landings. The mean CM to ground contact and the horizontal was 87". Trunk to horizontal at landing was 134", and thigh to horizontal at landing was 107". Selected parameters of the results presented in this study may be used to form a representative biomechanical profile for horizontal bar landings

University of Canberra: Healthpact Research Centre for Health Promotion and Wellbeing

The HRCHPW is a multidisciplinary research centre, working to conduct health promotion and wellbeing research and evaluation in partnership with other organisations and communities in the Australian Capital Territory. The research undertaken by the Centre will be linked to the key issues which impact on the health and wellbeing of the ACT community as outlined in the Canberra Plan and the ACT Health Promotion Board’s Strategic Plan

Turbulent Supersonic/Hypersonic Heating Correlations for Open and Closed Cavities

Supersonic/hypersonic laminar heating correlations that were developed for damage assessment analysis of atmospheric re-entry vehicles have been modified and extended to cover fully-turbulent conditions over rectangular cavity geometries that are aligned with the local velocity. Turbulent boundary layer properties were computationally determined and used to develop the cavity geometry parametrics and to correlate experimental closed cavity heating data to yield new relationships for the floor-averaged and centerline endwall peak-heating augmentation. With the form of the closed-cavity correlations established, historical data were used to develop new correlations for turbulent open-cavity heating

Calculation of Effective Coulomb Interaction for Pr3+Pr^{3+}, U4+U^{4+}, and UPt3UPt_3

In this paper, the Slater integrals for a screened Coulomb interaction of the the Yukawa form are calculated and by fitting the Thomas-Fermi wavevector, good agreement is obtained with experiment for the multiplet spectra of $Pr^{3+}$ and $U^{4+}$ ions. Moreover, a predicted multiplet spectrum for the heavy fermion superconductor $UPt_3$ is shown with a calculated Coulomb U of 1.6 eV. These effective Coulomb interactions, which are quite simple to calculate, should be useful inputs to further many-body calculations in correlated electron metals.Comment: 8 pages, revtex, 3 uuencoded postscript figure