Sample Size Effects on Ultrasonic Measurements of Elastic Moduli—Experimental and Theoretical Investigations

AbstractNation-wide data in Japan on births and prenatal deaths of 16 sets of quintuplets during 1974-1985 were analysed. Among the 16 sets, 3 sets were liveborn, 8 were stillborn, and 5 were mixed, with a stillbirth rate of 0.64 (51/80). Effects of sex, maternal age and birth order on the stillbirth rate were not considered because of the small sample size. Effects of gestational age and birthweight on stillbirth rate were also examined. The mean weight of the 40 quintuplet individuals was 1,048 g.

Download Full-text

Ultrasonic Measurements of Elastic Moduli of Thermally Cycled Metal Matrix Composite Precursor Wires

Nondestructive Methods for Material Property Determination ◽

10.1007/978-1-4684-4769-9_26 ◽

1984 ◽

pp. 327-336

Author(s):

Robert W. Reed ◽

Albert L. Bertram

Keyword(s):

Metal Matrix Composite ◽

Matrix Composite ◽

Metal Matrix ◽

Elastic Moduli ◽

Ultrasonic Measurements

Download Full-text

Is there an early Far Western Lapita province? Sample size effects and new evidence from Eloaua Island

Archaeology in Oceania ◽

10.1002/j.1834-4453.1987.tb00176.x ◽

1987 ◽

Vol 22 (3) ◽

pp. 123-127 ◽

Cited By ~ 10

Author(s):

P.V. Kirch ◽

M.S. Allen ◽

V.L. Butler ◽

T.L. Hunt

Keyword(s):

Sample Size ◽

Size Effects ◽

New Evidence

Download Full-text

On the Size Effects in Micro/Meso Upsetting of Brass H62 at Elevated Temperatures

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.621.158 ◽

2014 ◽

Vol 621 ◽

pp. 158-164

Author(s):

Hao Yan Wang ◽

Zhe He Yao ◽

De Qing Mei

Keyword(s):

Flow Stress ◽

Sample Size ◽

Size Effects ◽

Metal Forming ◽

Room Temperature ◽

Production Efficiency ◽

Elevated Temperatures ◽

Processing Temperature ◽

High Production ◽

Scaling Down

Micro/meso forming, as an emerging manufacturing process for miniature metallic workpieces, has attracted great attention since the 1990s due to its high production efficiency, low material waste and high precision. Due to the so-called size effects in the scaling down, many traditional theories in metal forming cannot be simply applied to the micro/meso forming. In this study, the micro/meso upsetting experiments of Brass H62 were conducted at various temperatures. The stress−strain curves in the experiments were measured and compared. The effects of the temperature and the sample size on the flow stress were discussed. It is found that the flow stress of the material decreased with the decrease of the sample size at room temperature. However, the flow stress of the material may increase with the decrease of the sample size at elevated temperatures. The results indicate that the size effects in the micro/meso forming are significantly affected by the processing temperature.

Download Full-text

Mechanical Properties and Size Effects of ZnO Nanowires Studied by First-Principles Calculation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.654-656.1670 ◽

2010 ◽

Vol 654-656 ◽

pp. 1670-1673

Author(s):

Zhan Jun Gao ◽

You Song Gu ◽

Yue Zhang

Keyword(s):

Mechanical Properties ◽

First Principles ◽

Size Effects ◽

Density Functional ◽

Elastic Moduli ◽

Axial Direction ◽

Zno Nanowires ◽

First Principles Calculation ◽

Different Diameters ◽

Ground State Energies

First-principles density functional calculations were performed to investigate mechanical properties of ZnO nanowires and the size effects. Structural optimizations were performed first, and a series of strains were applied to the nanowires in the axial direction. The ground state energies were calculated and the elastic moduli of ZnO nanowires were obtained from the energy versus strain curves. It is found that the elastic moduli of the ZnO nanowires with three different diameters (1.2, 1.5 and 1.8nm) are 136.3, 138.7 and 138.0 GPa, respectively, and that of bulk ZnO along [0001] direction is 140.1 GPa. The elastic modulus of ZnO nanowire is slightly lower than that of the bulk and it decreases as the diameter decreases. Comparisons to experimental results and theoretical predications are made.

Download Full-text