Study on significance of pillar dimensions on stability of caverns in rocks with high overburden.

The present study aims to examine the influence of pillar widths on the stability of caverns. Case study considering two caverns viz. Powerhouse Cavern (PHC) and Transformerhall Cavern (TC), in a major hydro-electric project in the eastern Himalayas is considered. 2D and 3D numerical analysis was carried out for w/B ratios 1.5 and 3.0 respectively. Primary aspects like major principal stress and development of plastic zone were investigated for the two pillar widths. An optimum pillar width was observed that resulted in reduced stress acting along the cavern periphery, a better stress distribution, and no overlap of plastic zones between the caverns. Further, the optimum pillar width resulted in a better stress-redistribution with progress of excavation and the in-situ stress became constant at an earlier stage of excavation. Observations from comparative analysis revealed that a pillar width nearly equal to the largest dimension or twice the width of the larger of the caverns in the group resulted in a better stability and hence can be considered as the optimum width. Furthermore, the analysis suggests that along the pillar width, maximum stress was observed at mid-height, and it is more in the vicinity of the face of the caverns.

Empirical relation to evaluate blast induced crack development zone while using explosives of different detonation pressure in opencast bench blasting.

The optimum utilisation of explosive energy in the rock blasting operation is a prime challenge for the blast designers. The explosive energy in this operation is used for movement of burden. The optimum fracturing of the rock mass to meet the production demand takes place along tension. In the process of blasting, the detonation pressure of the explosives in the blasthole induces shock wave to the rock mass. The propagating shock wave is initially compressive in nature and becomes tensile after being reflected from the free face. The extent of tensile damage zone would give the optimum burden for blasting. The explosive properties along with the rock mass properties and charge configuration influences the extent of tensile damage zone. In this study, an empirical relation has been developed for estimation of blast induced tensile damage zone. The experimental trials were conducted at a coal mine using two different types of explosives for the validation of the developed empirical relation. The ground vibration predictors were developed using the data of experimental trials. The induced damage zone was computed using empirical relation proposed by Forsyth (1993) and developed ground vibration predictors. The estimated damage zone using developed empirical predictor and Forsyth relation were compared. The difference in the induced damage zone using two approaches is within 10%. The predicted values using developed empirical relation are accurate with RMSE value of 0.227 m. Hence, the developed empirical relation would be beneficial for estimation of blast induced crack zone.

Trauma and children: Exploring posttraumatic growth among school children impacted by armed conflict in Kashmir.

Despite a growing body of literature showing evidence of posttraumatic growth (PTG) in adult populations from various cultures, very few studies have examined PTG among children, particularly from conflict zones in South Asia. Given this situation, the present study examined PTG among 815 school children of 12 to 18 years age, who had lost one or both parents as a result of protracted armed conflict in Kashmir, India. In a cross-sectional study, the hypothesized relationship of core beliefs challenges, religious coping, religious commitment, sociocultural context, and some demographic variables with posttraumatic growth (PTG) were examined. Results suggest that sociocultural context, core beliefs challenges, and religious coping predicted PTG, thus affirming the role of sociocultural environment in the development of PTG among children. Practical implications and future directions are discussed. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Effect of aluminum content on detonation velocity and density of emulsion explosives.

The performance of nonideal explosives, such as emulsion explosives, can be altered by metal powders like aluminum (Al) while keeping their other components the same. The high demand of emulsions coupled with various specific requirements, recommends a study on the performance of explosives. A research study on the detonation velocity of emulsion explosives variation with varying Al content in the emulsion matrix was carried out. The Al content in the emulsion matrix was varied from 0 to 20% and the corresponding density and detonation velocity (confined and unconfined) were measured. The misfire of emulsion explosives occurred at 20% Al content both in confined and unconfined conditions. The paper also focuses on the emulsion's density dependence on different Al content. The variation of density observed was in the range from 1.16 to 1.42 g/cc. The results obtained can be used by blasting engineers to design higher explosives.

Diabetes mellitus with pulmonary tuberculosis--a double trouble.

Diabetic patients are often at a higher risk for developing several types of infections and infection does alter the handling of glucose by tissues. Pulmonary infections in diabetics are characterised by alteration in host defence, in entire body and in the lung locally as well as in the function of respiratory epithelium and ciliary motility. Association between diabetes mellitus and pulmonary tuberculosis is well established, while the prevalence of tuberculosis is increased 4-5 times more among diabetics. Impairment of host defence plays an important role for changing the clinical, radiological and bacteriological presentation in diabetic patients. It is also reported by the various studies that hyperglycaemia favours the growth of tuberculosis bacilli. So the severity of tuberculosis appears more cirtical with the degree of hyperglycaemia and host defence activity. This overlap between the diabetic and tuberculosis epidemics could adversely affect global tuberculosis control efforts.