A Study of Optoelectronic Scale Model of Full‐Size Target

Radio Science ◽  
2019 ◽  
Author(s):  
Jin Li ◽  
Xiaoyi Feng
Keyword(s):  
Scale Model ◽  
Full Size ◽  
Size Target

Turn-Up and Turn-Down in Hot Rolling: A Study on a Model Mill Using Plasticine

1972 ◽  
Vol 14 (4) ◽  
pp. 245-254 ◽  
Author(s):  
S. A. E. Buxton ◽  
S. C. Browning
Keyword(s):  
Hot Rolling ◽  
Surface Friction ◽  
Scale Model ◽  
Speed Ratio ◽  
Strain Component ◽  
Full Size ◽  
Plastic Yield ◽  
Steel Slabs ◽  
Work Rolls ◽  
Better Than

Turn-up and turn-down is a phenomenon which occurs in the hot rolling of flat products when the nose of a slab, or the whole slab, curls up or down upon emerging from the rolls and remains deformed unless subsequently straightened. Turn-up and turn-down can be troublesome to production, since it can cause damage to the mill rolls, housing, and run-out tables and can also cause production delays due to the difficulty of re-rolling a deformed slab. The object of this paper is to determine the main factors governing the phenomenon, to obtain quantitative relationships between causes and effects, and to suggest means of preventing curvature occurring. The best approach was considered to be a scale model using plasticine to simulate the hot metal. As a basis for the work, several dimensionless ratios are formed which have to be the same in both model and full size mill, if the model is to be both dynamically and geometrically similar. In the more important dimensionless ratios, account is taken of the plastic yield characteristics of the material, including the rate-of-strain component, of the stresses due to surface friction and gravity, and finally of the ratio of roll speeds. The results are compared with some previous work by others on steel slabs using a full size mill. In all respects, the results agree closely. The most significant factor affecting turn-up and turn-down is the ratio of surface speeds of the two work-rolls. Curvature is proportional to this speed ratio, but slipping at the rolls may modify this relationship. For a given angle of entry, the ratio of torque upon each roll is a function of the speed ratio. Angle of entry has negligible effect on turn-up and turn-down, but has a powerful effect upon the torque ratio. Slip is very undesirable and it appears that the roll surface finish should not be better than necessary if slip is to be avoided. To produce a flat slab, a speed ratio of about 0·97 is required in the model. In practice, this may be achieved either directly by controlling the speed ratio, or indirectly by controlling the torque ratio, provided the angle of entry is constant.

Prediction of the vibration characteristics of a full-size structure from those of a scale model

2002 ◽  
Vol 80 (18-19) ◽  
pp. 1461-1472 ◽  
Author(s):  
Jia-Jang Wu ◽  
M.P. Cartmell ◽  
A.R. Whittaker
Keyword(s):  
Size Structure ◽  
Vibration Characteristics ◽  
Scale Model ◽  
Full Size

An Axial Turbobrake

1992 ◽  
Vol 114 (2) ◽  
pp. 419-425 ◽  
Author(s):  
M. I. Goodisman ◽  
M. L. G. Oldfield ◽  
R. C. Kingcombe ◽  
T. V. Jones ◽  
R. W. Ainsworth ◽  
...  
Keyword(s):  
Scale Model ◽  
Exhaust Gas ◽  
Two Dimensional ◽  
Aerodynamic Design ◽  
Dimensional Theory ◽  
Full Size ◽  
High Stage ◽  
Transonic Turbine ◽  
Fast Acting ◽  
Highly Loaded

The “Axial Turbobrake” (patent applied for) is a novel turbomachine that can be used to absorb power generated by test turbines. Unlike a compressor, there is no pressure recovery through the turbobrake. This simplifies the aerodynamic design and enables high-stage loadings to be achieved. The blades used have high-turning two-dimensional profiles. This paper describes a single-stage axial turbobrake, which is driven by the exhaust gas of the test turbine and is isolated from the turbine by a choked throat. In this configuration no fast-acting controls are necessary as the turbobrake operates automatically with the turbine flow. Tests on a 0.17 scale model show that the performance is close to that predicted by a simple two-dimensional theory, and demonstrate that the turbobrake power absorption can be controlled and hence matched to that typically produced by the first stage of a modern highly loaded transonic turbine. A full-size axial turbobrake will be used in a short-duration rotating turbine experiment in an Isentropic Light Piston Tunnel at RAE Pyestock.

scholarly journals An Axial Turbobrake

1991 ◽  
Author(s):  
M. I. Goodisman ◽  
M. L. G. Oldfield ◽  
R. C. Kingcombe ◽  
T. V. Jones ◽  
R. W. Ainsworth ◽  
...  
Keyword(s):  
Scale Model ◽  
Exhaust Gas ◽  
Two Dimensional ◽  
Aerodynamic Design ◽  
Dimensional Theory ◽  
Full Size ◽  
High Stage ◽  
Transonic Turbine ◽  
Fast Acting ◽  
Highly Loaded

The Axial Turbobrake (Patent applied for) is a novel turbomachine which can be used to absorb power generated by test turbines. Unlike a compressor there is no pressure recovery through the turbobrake. This simplifies the aerodynamic design and enables high stage loadings to be achieved. The blades used have high turning two dimensional profiles. This paper describes a single stage axial turbobrake, which is driven by the exhaust gas of the test turbine and is isolated from the turbine by a choked throat. In this configuration no fast acting controls are necessary as the turbobrake operates automatically with the turbine flow. Tests on a 0.17 scale model, show that the performance is close to that predicted by a simple two-dimensional theory, and demonstrate that the turbobrake power absorption can be controlled and hence matched to that typically produced by the first stage of a modern highly loaded transonic turbine. A full size axial turbobrake will be used in a short duration rotating turbine experiment in an Isentropic Light Piston Tunnel at RAE Pyestock.

Modeling Within-Person Variance in Reaction Time Data of Older Adults

GeroPsych ◽  
2011 ◽  
Vol 24 (4) ◽  
pp. 169-176 ◽  
Author(s):  
Philippe Rast ◽  
Daniel Zimprich
Keyword(s):  
Reaction Time ◽  
Cognitive Aging ◽  
Reaction Times ◽  
Reaction Time Task ◽  
Reaction Time Data ◽  
Scale Model ◽  
Time Data ◽  
Time Task ◽  
The Mean ◽  
Second Wave

In order to model within-person (WP) variance in a reaction time task, we applied a mixed location scale model using 335 participants from the second wave of the Zurich Longitudinal Study on Cognitive Aging. The age of the respondents and the performance in another reaction time task were used to explain individual differences in the WP variance. To account for larger variances due to slower reaction times, we also used the average of the predicted individual reaction time (RT) as a predictor for the WP variability. Here, the WP variability was a function of the mean. At the same time, older participants were more variable and those with better performance in another RT task were more consistent in their responses.

Using the Rating Scale Model to Examine the Psychometric Properties of the Self-Efficacy Scale for Driver Competence

2011 ◽  
Vol 27 (3) ◽  
pp. 164-170 ◽  
Author(s):  
Anna Sundström
Keyword(s):  
Psychometric Properties ◽  
Self Efficacy ◽  
Rating Scale ◽  
Measurement Precision ◽  
The Self ◽  
Test Theory ◽  
Self Report ◽  
Scale Model ◽  
Validity And Reliability ◽  
Two Samples

This study evaluated the psychometric properties of a self-report scale for assessing perceived driver competence, labeled the Self-Efficacy Scale for Driver Competence (SSDC), using item response theory analyses. Two samples of Swedish driving-license examinees (n = 795; n = 714) completed two versions of the SSDC that were parallel in content. Prior work, using classical test theory analyses, has provided support for the validity and reliability of scores from the SSDC. This study investigated the measurement precision, item hierarchy, and differential functioning for males and females of the items in the SSDC as well as how the rating scale functions. The results confirmed the previous findings; that the SSDC demonstrates sound psychometric properties. In addition, the findings showed that measurement precision could be increased by adding items that tap higher self-efficacy levels. Moreover, the rating scale can be improved by reducing the number of categories or by providing each category with a label.

An IRT Investigation of the Validity of Non-Patient Analogue Research Using the Beck Depression Inventory

1995 ◽  
Vol 11 (1) ◽  
pp. 14-20 ◽  
Author(s):  
Sean M. Hammond
Keyword(s):  
Differential Item Functioning ◽  
Beck Depression Inventory ◽  
Rating Scale ◽  
Latent Trait ◽  
Scale Model ◽  
Item Functioning ◽  
Two Samples ◽  
Patient Groups ◽  
Analogue Research ◽  
Rating Scale Model

This paper presents an IRT analysis of the Beck Depression Inventory which was carried out to assess the assumption of an underlying latent trait common to non-clinical and patient samples. A one parameter rating scale model was fitted to data drawn from a patient and non-patient sample. Findings suggest that while the BDI fits the model reasonably well for the two samples separately there is sufficient differential item functioning to raise serious duobts of the viability of using it analogously with patient and non-patient groups.

Modeling Intraindividual Variability in Three-Level Multilevel Models

Methodology ◽  
2018 ◽  
Vol 14 (3) ◽  
pp. 95-108 ◽  
Author(s):  
Steffen Nestler ◽  
Katharina Geukes ◽  
Mitja D. Back
Keyword(s):  
Multilevel Model ◽  
Multilevel Models ◽  
Mixed Effects ◽  
Repeated Measurements ◽  
Scale Model ◽  
Suggested Approach ◽  
Psychological Study ◽  
Level Data ◽  
Ecological Momentary ◽  
Momentary Assessment

Abstract. The mixed-effects location scale model is an extension of a multilevel model for longitudinal data. It allows covariates to affect both the within-subject variance and the between-subject variance (i.e., the intercept variance) beyond their influence on the means. Typically, the model is applied to two-level data (e.g., the repeated measurements of persons), although researchers are often faced with three-level data (e.g., the repeated measurements of persons within specific situations). Here, we describe an extension of the two-level mixed-effects location scale model to such three-level data. Furthermore, we show how the suggested model can be estimated with Bayesian software, and we present the results of a small simulation study that was conducted to investigate the statistical properties of the suggested approach. Finally, we illustrate the approach by presenting an example from a psychological study that employed ecological momentary assessment.

Objects and Relations in Young Children's Use of a Scale Model

1992 ◽  
Author(s):  
Judy DeLoache ◽  
Don Marzolf ◽  
David Uttal ◽  
Jill Schreiber
Keyword(s):  
Scale Model
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