scholarly journals Introducing platform surface interior angle (PSIA) and its role in flake formation, size and shape

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241714
Author(s):  
Shannon P. McPherron ◽  
Aylar Abdolahzadeh ◽  
Will Archer ◽  
Annie Chan ◽  
Igor Djakovic ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Predictive Power ◽  
Controlled Experiments ◽  
Past Behavior ◽  
Lithic Assemblages ◽  
Controlled Experimentation ◽  
Cone Formation ◽  
Material Sciences ◽  
Individual Variables ◽  
Hertzian Cone

Four ways archaeologists have tried to gain insights into how flintknapping creates lithic variability are fracture mechanics, controlled experimentation, replication and attribute studies of lithic assemblages. Fracture mechanics has the advantage of drawing more directly on first principles derived from physics and material sciences, but its relevance to controlled experimentation, replication and lithic studies more generally has been limited. Controlled experiments have the advantage of being able to isolate and quantify the contribution of individual variables to knapping outcomes, and the results of these experiments have provided models of flake formation that when applied to the archaeological record of flintknapping have provided insights into past behavior. Here we develop a linkage between fracture mechanics and the results of previous controlled experiments to increase their combined explanatory and predictive power. We do this by documenting the influence of Herztian cone formation, a constant in fracture mechanics, on flake platforms. We find that the platform width is a function of the Hertzian cone constant angle and the geometry of the platform edge. This finding strengthens the foundation of one of the more influential models emerging from the controlled experiments. With additional work, this should make it possible to merge more of the experimental results into a more comprehensive model of flake formation.

Structural Integrity Procedures for Naval Ships

1980 ◽  
Vol 102 (1) ◽  
pp. 7-14 ◽  
Author(s):  
P. M. Palermo
Keyword(s):  
Life Cycle ◽  
Fracture Mechanics ◽  
Nondestructive Testing ◽  
Structural Design ◽  
Structural Integrity ◽  
High Strength ◽  
Production Engineering ◽  
The Past ◽  
The Future ◽  
Material Sciences

The application of both light and heavy sections of high strength metals in weight sensitive ships demands that structural integrity principles be followed during all stages of design, fabrication and life-cycle support of ship structures. The integration of the interfacing disciplines of material sciences, fracture mechanics, structural design, welding engineering, production engineering and nondestructive testing are necessary ingredients of the Navy’s structural integrity plan. The relationships of these groups in the past, and envisioned in the future, are discussed. Results of early structural integrity efforts for present day ships as well as structural integrity aspects of ongoing designs are also discussed.

scholarly journals Prediction of Hypertension Based on Facial Complexion

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 540
Author(s):  
Lin Ang ◽  
Bum Ju Lee ◽  
Honggie Kim ◽  
Mi Hong Yim
Keyword(s):  
Predictive Power ◽  
Prediction Models ◽  
Color Space ◽  
Information Criterion ◽  
Selection Methods ◽  
Cielab Color Space ◽  
Individual Variables ◽  
Crude Analysis ◽  
The Bayesian Approach ◽  
Cielab Color

This study aims to investigate the association between hypertension and facial complexion and determine whether facial complexion is a predictor for hypertension. Using the Commission internationale de l’éclairage L*a*b* (CIELAB) color space, the facial complexion variables of 1099 subjects were extracted in three regions (forehead, cheek, and nose) and the total face. Logistic regression was performed to analyze the association between hypertension and individual color variables. Four variable selection methods were also used to assess the association between hypertension and combined complexion variables and to compare the predictive powers of the models. The a* (green-red) complexion variables were identified as strong predictors in all facial regions in the crude analysis for both genders. However, this association in men disappeared, and L* (lightness) variables in women became the strongest predictors after adjusting for age and body mass index. Among the four prediction models based on combined complexion variables, the Bayesian approach obtained the best predictive in men. In women, models using three different methods but not the stepwise Akaike information criterion (AIC) obtained similar AUC values between 0.82 and 0.83. The use of combined facial complexion variables slightly improved the predictive power of hypertension in all four of the models compared with the use of individual variables.

Bi-Axial Flexure Strength, Weibull Modulus and Fracture Mode of Alumina Glass-Infiltrated Core/Veneer Ceramic Composites

2007 ◽  
Vol 353-358 ◽  
pp. 1556-1559 ◽  
Author(s):  
Jun Cui ◽  
Yi Fan Chen ◽  
Yong Lie Chao ◽  
Chun Xia Chen ◽  
Jun Ou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Flexural Strength ◽  
Fracture Mode ◽  
Weibull Modulus ◽  
Ceramic Composites ◽  
Core Material ◽  
Flexure Strength ◽  
Cone Formation ◽  
Hertzian Cone ◽  
Scanning Electron

The purpose of this study is to determine the bi-axial flexural strength, weibull modulus and fracture mode of bilayered alumina glass-infiltrated core and the veneering porcelain. Forty disk specimens were fabricated from alumina glass-infiltrated core (HSDC-A) and veneer porcelain (Vintage AL). The specimens were equally divided into four groups as: MV, monolithic specimens of veneer material; MC, monolithic specimens of core material; BV, bilayered specimens with the veneer in tension; BC, bilayered specimens with core material in tension. Mean flexure strength, standard deviation and associated Weibull modulus were determined using bi-axial flexure (ball-on-ring) for each group. Both optical and scanning electron microscopy were employed for identification of the fracture mode and origin. The surface loaded in tension influenced the bi-axial flexural strength and reliability of the composites. The frequency of specimen delamination, Hertzian cone formation and sub-critical radial cracking in the bilayered discs are also dependent on the surface loaded in tension.

Development of a German-Language Questionnaire to Measure Collective Orientation as an Individual Attitude

2017 ◽  
Vol 76 (3) ◽  
pp. 91-105 ◽  
Author(s):  
Vera Hagemann
Keyword(s):  
Team Performance ◽  
Reliability And Validity ◽  
Future Research ◽  
German Language ◽  
Team Members ◽  
Collective Orientation ◽  
Team Research ◽  
German Speaking ◽  
Individual Variables ◽  
The Individual

Abstract. The individual attitudes of every single team member are important for team performance. Studies show that each team member’s collective orientation – that is, propensity to work in a collective manner in team settings – enhances the team’s interdependent teamwork. In the German-speaking countries, there was previously no instrument to measure collective orientation. So, I developed and validated a German-language instrument to measure collective orientation. In three studies (N = 1028), I tested the validity of the instrument in terms of its internal structure and relationships with other variables. The results confirm the reliability and validity of the instrument. The instrument also predicts team performance in terms of interdependent teamwork. I discuss differences in established individual variables in team research and the role of collective orientation in teams. In future research, the instrument can be applied to diagnose teamwork deficiencies and evaluate interventions for developing team members’ collective orientation.

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