Results 41 to 50 of about 4,310 (220)

Rock burst mechanism induced by stress anomaly in roof thickness variation zone: a case study

Geomatics, Natural Hazards & Risk, 2022
The variation of hard roof thickness is an essential contributor in triggering rock bursts during longwall mining. Case analysis and numerical modeling were used to study the stress and energy characteristics of the coal and rock mass and its fracture ...
Xianxi Bai, Anye Cao, Wu Cai, Yingyuan Wen, Yaoqi Liu, Songwei Wang, Xuwei Li   +6 more
doaj   +1 more source

Study on the Mechanism and Prevention of Frequent Mine Seismic Events in Goaf Mining under a Multi-Layer Thick Hard Roof: A Case Study

, 2023
Mine seismic events are an inevitable dynamic phenomenon occurring in deep mines. A scientific and rational method is needed to evaluate and understand mine seismicity and its induced disasters. In the Ordos mining area of North China, multiple groups of
Junpeng Ma, Jinwen Bai, Zhongxiang Gao, Sitao Zhu, Zhu Li, Bo Wang, Guorui Feng, Wenda Wu   +7 more
core   +1 more source

Evolution of roof treatment processes from blasting to hydraulic fracturing to prevent rockburst in thick-hard roof coal mines in Xinjiang, China

Frontiers in Earth Science
Rockburst prevention poses a major challenge in coal mining, with thick and hard roof strata being the primary cause of rockbursts. To analyze the feasibility and effectiveness of using hydraulic fracturing as an alternative to blasting methods for ...
Kunlun Liu, Taotao Du, Taotao Du, Yuhai Wu, Hongping Li, Xu Yang, Jiang Liu, Hongbao Liang, Jianqi Wang   +8 more
doaj   +1 more source

Osteological correlates of the respiratory and vascular systems in the neural canals of Mesozoic ornithurines Ichthyornis and Janavis

The Anatomical Record, EarlyView.
Abstract In birds, the neural canal houses a variety of anatomical structures including the spinal cord, meninges, spinal vasculature, and respiratory diverticula. Among these, paramedullary diverticula and the extradural dorsal spinal vein may leave behind osteological correlates in the form of pneumatic foramina and fossae, and a bilobed geometry of ...
Jessie Atterholt, M. Grace Burton, Mathew J. Wedel, Juan Benito, Ellen Fricano, Daniel J. Field   +5 more
wiley   +1 more source

Fractural structure of thick hard roof stratum using long beam theory and numerical modeling

, 2017
The thick hard rock (THR) roof of the long-wall mining face is prone to the large-sized cantilever roof, and its sudden fracture will cause serious rock dynamic disasters, such as coal and gas outburst and rockburst. In this study, based on the long beam
Zhao, Tong, Kaan Yetilmezsoy, Changyou Liu, Shuai Zhang, Liu, Changyou, Zhang, Shuai, Zhang, Baisheng, Tong Zhao, Yetilmezsoy, Kaan, Baisheng Zhang   +9 more
core   +1 more source

Functional anatomy, jaw mechanisms, and feeding behavior of Dunkleosteus terrelli (Placodermi, Arthrodira)

The Anatomical Record, EarlyView.
A new musculoskeletal reconstruction and revision of the cranio‐mandibular anatomy of the Devonian arthrodire placoderm Dunkleosteus terrelli from a comparative and functional anatomical perspective. Dunkleosteus is a specialized arthrodire with many specializations for feeding on large vertebrates, and many of its features are part of broader ...
Russell K. Engelman, Robert K. Carr, Kate Trinajstic, Zerina Johanson, Oleg A. Lebedev   +4 more
wiley   +1 more source

The coelurosaur theropods of the Romualdo formation, early Cretaceous (Aptian) of Brazil: Santanaraptor placidus meets Mirischia asymmetrica

The Anatomical Record, EarlyView.
Abstract The upper carbonate concretion levels of the Romualdo Formation (Aptian, Brazil) have yielded several theropod dinosaur remains, including spinosaurids and the coelurosaurs Santanaraptor placidus and Mirischia asymmetrica, the phylogenetic affinities of which are controversial.
Rafael Delcourt, Orlando Nelson Grillo, Christophe Hendrickx, Maximilian Kellermann, Max Cardoso Langer   +4 more
wiley   +1 more source

Re‐evaluation of a soft crested Edmontosaurin, with implications for hadrosaurid life appearance and diversity

The Anatomical Record, EarlyView.
Abstract Hadrosaurid dinosaurs are generally regarded as “crested” or “non‐crested” depending on the presence or absence of a bony cranial crest. At least one supposedly “non‐crested” hadrosaur is known to have possessed a soft tissue cranial crest (or comb), based on an exceptionally preserved “mummified” specimen. Here we redescribe this specimen and
Henry S. Sharpe, Phil R. Bell, Ian Baylatry, Robin Sissons, Corwin Sullivan   +4 more
wiley   +1 more source

Mechanism of grouped collapse of thick and hard roof for gob-side entry retaining combined backfill in fully-mechanized caving face

Meitan xuebao
A large range of caving roof of gob-side entry retaining is easy to cause impact damage of the roadside backfill body. In order to ensure the stability of gob-side entry retaining, different from the traditional large-angle inclined roof cutting method ...
Guorui FENG, Zijie MA, Wenda WU, Jianbiao BAI, Sunwen DU, Jinwen BAI, Lujin HE   +6 more
doaj   +1 more source

The cranial, mandibular, and hyoid anatomy of softshell turtles (Trionychidae): A revised character list for phylogenetic analysis

The Anatomical Record, EarlyView.
Abstract Softshell turtles (Pan‐Trionychidae) are an early branching clade of hidden‐necked turtles (Cryptodira) with a rich fossil record extending back to the Early Cretaceous. The evolutionary history of softshell turtles is still unresolved because of their conservative morphology combined with high levels of polymorphism related to morphological ...
Léa C. Girard, Walter G. Joyce
wiley   +1 more source