Results 81 to 90 of about 104,884 (306)

Attenuation law of MWD pulses in aerated drilling

Petroleum Exploration and Development, 2012
A mathematical model for predicting the attenuation of measurement while drilling (MWD) pressure pulses in aerated drilling was proposed using the two-phase flow model and considering the momentum and energy exchange at the phase interface, gravity of ...
Hongtao LI, Gao LI, Yingfeng MENG, Gang SHU, Kuanliang ZHU, Xiaofeng XU   +5 more
doaj   +1 more source

Imaging the attenuation coefficients of positron beams in matter: positron attenuation tomography [PDF]

EJNMMI Physics, 2015
A new positron annihilation imaging modality is described that enables nondestructive measurement of the linear attenuation coefficients (LACs) of positron beams in heterogeneous materials. This positron attenuation tomography (PAT) technique utilizes a positron emission tomography (PET) system embedded within a uniform static magnetic field, such as ...
openaire   +2 more sources

White Matter Microstructural Abnormalities in Neonatal Onset Genetic Epilepsy

Annals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Objective Recent evidence indicates that epilepsy is associated with abnormal white matter. If seizures alter white matter, then the impact upon network function, epileptogenesis, and cognition could be pronounced in neonates undergoing rapid developmental myelination. Neonates with epilepsy due to nonstructural genetic causes provide a unique
Amanda G. Sandoval Karamian, Tianjia Zhu, Hao Huang, Shavonne L. Massey, Mark P. Fitzgerald, Darshana Parikh, Arastoo Vossough, Ingo Helbig, Nicholas S. Abend   +8 more
wiley   +1 more source

Estimation Method for Attenuation Coefficient of Thermal Radiation in Thermal Insulators by Using Thermal Conductivity

, 2011
A new method of estimating the attenuation coefficients of thermal radiation in thermal insulators was proposed. This is a means of deriving the attenuation coefficient using thermal conductivity of thermal insulators.
Makio Naito, Takahiro Ohmura, Masatake Onodera   +2 more
core   +1 more source

Beam attenuation coefficient data from Vayda ridge station JC094-STN044 of the James Cook cruise JC094

, 2021
The radiogenic isotope ratio 231Pa/230Th of seawater and ocean sediments is a potentially powerful tool for tracing oceanic processes such as the ocean circulation and marine primary productivity.
Robinson, Laura F, McManus, Jerry F, Rowland, George Henry, Ng, Hong Chin, Chen, Siyuan Sean   +4 more
core   +1 more source

Attenuation Law of Stress Waves in Cracked Rock Mass under Different Confining Pressures

Advances in Civil Engineering, 2019
Through theoretical analysis and indoor model tests, this paper explores the attenuation law of stress waves in the intact confined rock mass and cracked rock mass under different confining pressures, especially the relationship between the stress ...
Xiaoming Lou, Rui Luo, Jin Yu
doaj   +1 more source

Arctic Observations Identify Phytoplankton Community Composition as Driver of Carbon Flux Attenuation

Geophysical Research Letters, 2020
The attenuation coefficient b is one of the most common ways to describe how strong the carbon flux is attenuated throughout the water column. Therefore, b is an essential input variable in many carbon flux and climate models. Marsay et al. (2015, https:/
I. Wiedmann, E. Ceballos‐Romero, M. Villa‐Alfageme, A. H. H. Renner, C. Dybwad, H. van derJagt, C. Svensen, P. Assmy, J. M. Wiktor, A. Tatarek, M. Różańska‐Pluta, M. H. Iversen   +11 more
doaj   +1 more source

An inequality for longitudinal and transverse wave attenuation coefficients [PDF]

The Journal of the Acoustical Society of America, 2017
Total absorption, defined as the net flux of energy out of a bounded region averaged over one cycle for time harmonic motion, must be non-negative when there are no sources of energy within the region. This passivity condition places constraints on the non-dimensional absorption coefficients of longitudinal and transverse waves, γL and γT, in isotropic
openaire   +3 more sources

T1 Over Squared Proton Density Ratio to Characterize Multiple Sclerosis Lesions

Annals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Objective Differentiating remyelinated from demyelinated lesions in MS remains challenging without histological confirmation. This study introduces the T1‐to‐PD2 ratio (TPR) imaging approach and evaluates its ability to characterize MS lesions alongside other quantitative MRI (qMRI) metrics. Methods Thirty individuals with MS (mean age: 47.5 ± 
Sarah J. Wright, Scotty G. McKay, Jean Ramos Bou, Fen Bao, Vivian B. Truong, Chenyang Li, Li Jiang, Anza B. Memon, E. Mark Haacke, Yulin Ge, Yongsheng Chen   +10 more
wiley   +1 more source

Monte Carlo Probability To Determine Attenuation Coefficient In Identifying The Selectivity Properties Of Near-Infrared-Based Materials

Protek: Jurnal Ilmiah Teknik Elektro
Accurate attenuation coefficient measurements are able to display the nature of selectivity in an image. The methods used to measure the attenuation coefficient are Monte Carlo probability and linear regression models.
Rovika Trioclarise, Toto Aminoto, Yoni Rutiana Kusumawati, Ratu Karel lina   +3 more
doaj   +1 more source