Full Field Strain Analysis of Blasting Under High Stress Condition Based on Digital Image Correlation Method

The depth of mineral resources like coal continuously increases due to the exhaustion of shallow resources, and the characteristic of high ground stress in deep ground inevitably affects fracture of rock blasting. Combining with high-speed photography technology, the digital image correlation method (DIC) is introduced into experimental study on explosive mechanics. And strain evolution process of blasting under high stress condition is obtained by using the model experiment method. The preliminary results show that high stress condition has no obvious effects on the propagation law of blasting stress wave or its stress peak in the medium. In addition, it is found that medium in the “elastic vibration area” by conventional blast zoning is not always “elastic,” and on this basis, the concepts of “plastic area” and “quasielastic area” are put forward. The high stress condition does not influence partition range of above “plastic area” or “quasielastic area,” but in the “plastic area,” the high stress condition decreases both plastic strain value and its decay rate of relevant gauging points.

Effects of Stress and Task Difficulty on Working Memory and Cortical Networking

This study investigated interactive effects of stress and task difficulty on working memory and cortico-cortical communication during memory encoding. Thirty-eight adolescent participants (mean age of 15.7 ± 1.5 years) completed easy and hard working memory tasks under low- and high-stress conditions. We analyzed the accuracy and reaction time (RT) of working memory performance and inter- and intrahemispheric electroencephalogram coherences during memory encoding. Working memory accuracy was higher, and RT shorter, in the easy versus the hard task. RT was shorter under the high-stress (TENS) versus low-stress (no-TENS) condition, while there was no difference in memory accuracy between the two stress conditions. For electroencephalogram coherence, we found higher interhemispheric coherence in all bands but only at frontal electrode sites in the easy versus the hard task. On the other hand, intrahemispheric coherence was higher in the left hemisphere in the easy (versus hard task) and higher in the right hemisphere (with one exception) in the hard (versus easy task). Inter- and intracoherences were higher in the low- versus high-stress condition. Significant interactions between task difficulty and stress condition were observed in coherences of the beta frequency band. The difference in coherence between low- and high-stress conditions was greater in the hard compared with the easy task, with lower coherence under the high-stress condition relative to the low-stress condition. Stress seemed to cause a decrease in cortical network communications between memory-relevant cortical areas as task difficulty increased.

Design and Application of Secondary High-Capacity Support to Large-Section Tunnel Excavated in High-Stress Condition with Fractured Surrounding Rock

Aimed at the support problem of the deep large-section tunnel excavated in high-stress condition with fractured surrounding rock, the different characteristics of the stresses and displacements of the surrounding rock of the tunnel with different section supports and lateral pressure coefficients were analyzed using numerical simulation and theoretical calculation, so was the effect of the height of the double-layered I-section beam on the bearing capacity. Arched with bottom arch superimposed and fully-closed I-section beam suitable for large-section tunnel excavated in high-stress condition with fractured surrounding rock was developed. This support applies fully-closed and horse-shoe shaped structure with I-section beam overlapped and welded and its bearing capacity is 2.5 times higher than frequently-used I-section beam. Underground field testing showed that the deformation of the surrounding rock could be effectively controlled when the secondary arched with bottom arch superimposed and fully-closed I-section beam of high bearing capacity was used.

Anxiety and Ability to Recognize Clinical Information in Dentistry

Stress significantly affects a person’s cognitive ability to process information. Therefore, we hypothesized that patients’ ability to recognize information related to the procedure they are about to undergo will be affected by the stressfulness of the situation (less recognition under a high-stress situation as compared with a low-stress situation). Patients (n = 66) were evaluated for their ability to recognize clinical information supplied on two different occasions: immediately before oral surgery (high-stress condition) and before suture removal (low-stress condition). Dental and state of anxiety and expectation of pain were also assessed. On both occasions, the patients’ ability to recognize information correctly was low (less than 50%). Patients recognized significantly less information pre-operatively than before suture removal. State of anxiety, dental anxiety, and expectation to experience pain had a profound effect on their ability to recognize provided information correctly. Apparently, before dental treatment (high or low on stress), patients’ ability to process information may be severely impaired.

Coping with an ego‐threat: Monitoring and blunting during an intelligence test

This study investigated the predictive validity of the Miller Behavioral Style Scale (MBSS; Miller, 1987). Subjects had to work on an intelligence test. During this test, they could observe lights that informed them on how they were performing. There were two conditions: a low‐stress condition (n = 37) in which the lights always indicated that the subject was performing well, and a high‐stress condition (n.= 33) in which the lights signalled a deterioration of performance. In general, little support was found for the predictive validity of the MBSS.