• The Journal of Engineering Geology
• /
• v.34 no.1
• /
• pp.67-105
• /
• 2024

This study compares the quartzites of four quartzite units: The Fagfog Quartzite, Dunga Quartzite (member of the Robang Formation), Pandrang Quartzite (member of the Kalitar Formation) and the Chisapani Quartzite. The analysis shows variations in flakiness and elongation, as the Fagfog Quartzite displays low flakiness whereas the Pandrang and the Chisapani have moderate and the Dunga Quartzite has shown variations. The density values of the four quartzite units remain consistent, indicating uniform physical properties and porosity levels. However, bulk density values differ among the quartzites, suggesting variations in particle arrangement, porosity, and density. Regarding strength measures, the Pandrang and the Chisapani Quartzite have higher strength characteristics as compared to the Fagfog and the Dunga Quartzites. The Pandrang Quartzite has the highest average point load strength index, classifying it as "Extremely Strong". The resistance to impact and crushing forces varies among the quartzites, with lower Aggregate Impact Value (AIV) and Aggregate Crushing Value (ACV) indicating higher strength and durability. Durability tests show that the Fagfog Quartzite has high durability against slaking, with a slight decrease observed after the fifth cycle. The Dunga Quartzite shows varying degrees of weathering, while the Pandrang and the Chisapani Quartzite have minimal weight changes, indicating strong resistance to weathering. Magnesium sulfate soundness tests indicate high durability and resistance to degradation for all four units. The Los Angeles abrasion value (LAAV) tests indicate favorable resistance to abrasion for the majority of the Fagfog, Dunga, and the Pandrang Quartzites samples, while Chisapani Quartzite shows more variability in LAAV values. The Pandrang Quartzite shows a higher proportion of elongated particles but lower flakiness index values as compared to Fagfog and Dunga Quartzites while Chisapani Quartzite stands out with a significantly higher presence of flaky particles and lower elongation index values. Mechanically, the Fagfog and Dunga Quartzite show higher strength and better resistance to abrasion and freeze and thaw. The Pandrang Quartzite shows moderate resistance to crushing and sudden effect, while the Chisapani Quartzite has variable resistance to effect. This comparative study emphasizes the diversity and complexity of quartzite rock types, showing the need for comprehensive characterization and assessment to determine their suitability for specific applications.

• Journal of Korean Clinical Health Science
• /
• v.12 no.1
• /
• pp.1654-1659
• /
• 2024

Purpose: The aim of this study was to determine Correlation analysis of central corneal thickness, anterior chamber volume, and anterior chamber depth in Koreans aged 20 to 24 years using the Pentacam tool. Methods: The subjects of this study were 53 Korean adults with healthy eyes. The central corneal thickness(CCT), anterior chamber volume(ACV), and anterior chamber depth(ACD) was measured with Pentacam device. Data was analyzed by means of the Pearson's correlation cofficient. P-values<0.001 were considered statistically significant. Results: Mean age of subjects was 22.0±2.01 years. The mean +/- central corneal thickness of the right eye and left eye were 546.66±32.221mmg and 545.70±32.759mm, respectively. Also The mean central cornea thickness was 546.19 um in the whole sample. The mean anterior chamber volume the right eye and left eye was 181.66±33.738 mm³ and 180.12±30.84 mm³, respectively. The mean anterior chamber depth was 3.158±0.257 mm and 3.122±0.233 mm in right eye and left eye, respectively. There was a statistically significant difference between anterior camber volume and anterior chamber depth(p<0.001, Pearson's correlation). However there was no statistically significant difference between central cornea thickness and anterior chamber volume. Also there was no statistically significant difference between central cornea thickness and anterior chamber depth. Conclusion: The results of this study could be used as a clinical reference data for diagnosis and treatment of cornea in Korean adolescents.