Results 31 to 40 of about 177 (131)

Dynamic Analysis of Percussion Drilling System under Harmonic Impact

Shock and Vibration, 2021
As a new efficient rock-breaking technology, harmonic impact drilling technology has received great attention, but the research on its rock-breaking mechanism is insufficient, which limits its development.
Yijin Zeng, Shidong Ding, Jinchao Xu, Qunai Hu, Xiaojie Cui   +4 more
doaj   +1 more source

(Un)threading Rhythms: On Affect and Vibe in a Rave

Anthropology of Consciousness, EarlyView.
ABSTRACT In Toronto, raves arise across large nightclubs, DIY venues and outdoors, despite changing regulations that have further arranged and narrowed their possibility in the past 4 years. Following a rave in Toronto, this work explores ways that potentialities and affects emerge in a single night, through my entry of taking part in dancing and ...
Tatiana Yunadi
wiley   +1 more source

Early Bronze Age Copper Circulation in the Guadalentín and Segura Valleys (SE Spain)

Archaeometry, EarlyView.
ABSTRACT Identifying the sources of copper used in Early Bronze Age metalwork from south‐east Spain is key to resolving a long‐running debate concerning centralized control, or lack thereof, over El Argar society's economic organisation. This study provides the first substantial integrated programme of EDXRF and MC‐ICP‐MS analyses for copper‐base ...
Dirk Brandherm, Ignacio Montero‐Ruiz
wiley   +1 more source

Research on Axial-torsional Coupling Percussion Drilling Technology

Shiyou jixie, 2018
The solo axial or torsional percussion rock breaking technology with inherent limitations can no longer meet the current drilling development needs. Based on the in-depth study of axial and torsional percussion rock breaking drilling speed improvement ...
Mu Zongjie, Li Gensheng, Huang Zhongwei, Zang Chuanzhen   +3 more
doaj  

Chironomid‐based summer temperature reconstruction of the Eemian–Weichselian transition at Lichtenberg, northern Germany

Boreas, EarlyView.
Understanding the temperature variability of past interglacial cycles is essential to predict future climates. We present a new summer temperature reconstruction, based on the subfossil chironomid record from a small palaeolake adjacent to the Middle Palaeolithic site of Lichtenberg, northern Germany. The record spans from the Saalian late glacial over
Sonja Rigterink, Bartosz Kotrys, Michael Hein, Xuan Li, Neda Rahimzadeh, Agnieszka Gruszczyńska, Marcel Weiss, Brigitte Urban, David Colin Tanner, Tobias Lauer, Antje Schwalb   +10 more
wiley   +1 more source

Designed and Testing of the Positive Displacement Motor Driven Rotary Percussion Drilling Device

Shiyou jixie, 2016
The stability and service life of common rotary percussion drilling downhole tool is influenced by poor working conditions and is far from the field requirement. In view of this,a PDM driven drill string reciprocating percussion concept has been proposed,
Ma Guangjun, Zhang Haiping, Wang Jiachang   +2 more
doaj  

Towards an ‘absolute’ timing of biostratigraphic and environmental phases from the Saalian late glacial to the Weichselian pleniglacial in central Europe—Insights from a lacustrine succession in Lichtenberg, northern Germany

Boreas, EarlyView.
Palynological records are central to the biostratigraphic subdivision of the Late Pleistocene in central Europe. Yet many interglacial and interstadial phases—such as the Eemian, Brörup and Odderade—remain only poorly constrained in time due to limited numerical dating.
Michael Hein, Thomas Kasper, Alexis Badai Samudra, Martin Theuerkauf, Markus Lothar Fischer, Neda Rahimzadeh, Maria Sekar Proborukmi, Sonja Rigterink, Agnieszka Gruszczyńska, Christian Zeeden, Simon Parfitt, David John Horne, Lucy Roberts, Dustin White, Lisa Brogmus, Hans von Suchodoletz, Tobias Lauer, Marcel Weiss, David Colin Tanner, Brigitte Urban   +19 more
wiley   +1 more source

Numerical simulation of percussive drilling [PDF]

International Journal for Numerical and Analytical Methods in Geomechanics, 2015
SummaryThis paper presents a novel dynamical model to analyze the long‐term response of a percussive drilling system. This departs from existing approaches that usually consider a single activation and bit/rock interaction cycle for the analysis of the process performance.
Depouhon, Alexandre, Denoël, Vincent, Detournay, Emmanuel   +2 more
openaire   +1 more source

A bifacial paradise—The site of Ochtmissen, Germany, and its lithic assemblage in the context of the last glacial (early MIS 4) in the north‐central European Lowland

Boreas, EarlyView.
The Palaeolithic site of Ochtmissen (Lower Saxony, Germany) was excavated in fluvial terrace deposits during the winter of 1993/1994. The current study presents, for the first time, a thorough analysis of the lithic assemblage, encompassing its primary technological and typological characteristics, as well as the type and age of the fluvial deposits ...
Gianpiero Di Maida, Jutta Winsemann, Markus Fuchs, Niklas von Soest, Thomas Terberger   +4 more
wiley   +1 more source

Stem Cells From Dental Pulp, Periodontal Tissues, and Other Oral Sources: Biological Concepts and Regenerative Potential

Journal of Periodontal Research, EarlyView.
A graphical abstract recapping the different sources of dental, periodontal, and other oral‐derived mesenchymal stromal cells (MSCs) and their regenerative mechanisms and potentials. The review's article findings bridge fundamental biological science with translational advances, highlighting the significance of MSCs in craniofacial regenerative ...
Karim M. Fawzy El‐Sayed, Sara El Moshy, Israa Ahmed Radwan, Dina Rady, Aiah A. El‐Rashidy, Marwa M. S. Abbass, Christof E. Dörfer   +6 more
wiley   +1 more source