scholarly journals The rate of sedimentation from turbulent suspension: An experimental model with application to pyroclastic density currents and discussion on the grain-size dependence of flow runout

Sedimentology ◽  
2018 ◽  
Vol 66 (1) ◽  
pp. 129-145 ◽  
Author(s):  
Pierfrancesco Dellino ◽  
Fabio Dioguardi ◽  
Domenico M. Doronzo ◽  
Daniela Mele
Keyword(s):  
Grain Size ◽  
Experimental Model ◽  
Size Dependence ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Rate Of Sedimentation

scholarly journals Inverting Sediment Bedforms for Exploring the Hazard of Volcanic Density Currents Directly in the Field

2021 ◽  
Author(s):  
Pierfrancesco Dellino ◽  
Fabio Dioguardi ◽  
Roberto Sulpizio ◽  
Daniela Mele
Keyword(s):  
Phase Diagram ◽  
Grain Size ◽  
High Speed ◽  
Fluid Dynamic ◽  
Flow Behavior ◽  
Explosive Volcanism ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Particle Flows ◽  
First Time

Abstract Pyroclastic density currents are ground hugging gas-particle flows moving at high speed down the volcano slope. They are among the most hazardous events of explosive volcanism, causing devastation and deaths1,2. Because of the hostile nature they cannot be analyzed directly and most of their fluid dynamic behavior is reconstructed by the deposits left in the geological record, which frequently show peculiar structures such as bedforms of the types of ripples and dunes3,4. In this paper, we simplify a set of equations that link flow behavior to particle motion and deposition. This allows, for the first time, the build up of a phase diagram by which the hazard of dilute pyroclastic density currents can be explored easily and quickly by inverting bedforms wavelength and grain size.

scholarly journals The Entrainment Rate of Non‐Boussinesq Hazardous Geophysical Gas‐Particle Flows: An Experimental Model With Application to Pyroclastic Density Currents

2019 ◽  
Vol 46 (22) ◽  
pp. 12851-12861 ◽  
Author(s):  
P. Dellino ◽  
F. Dioguardi ◽  
D. M. Doronzo ◽  
D. Mele
Keyword(s):  
Experimental Model ◽  
Entrainment Rate ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Particle Flows

scholarly journals The mysterious grooves of Volcán Bárcena: a review of the role of streamwise counter-rotating vortices during erosion by dilute pyroclastic density currents

2021 ◽  
Vol 83 (4) ◽  
Author(s):  
Susan W. Kieffer ◽  
Eckart Meiburg ◽  
Jim Best ◽  
Joanna Austin
Keyword(s):  
Pyroclastic Density Currents ◽  
Density Currents

A discriminatory diagram of massive versus stratified deposits based on the sedimentation and bedload transportation rates. Experimental investigation and application to pyroclastic density currents

Sedimentology ◽  
2020 ◽  
Vol 67 (4) ◽  
pp. 2013-2039 ◽  
Author(s):  
Pierfrancesco Dellino ◽  
Fabio Dioguardi ◽  
Domenico Maria Doronzo ◽  
Daniela Mele
Keyword(s):  
Experimental Investigation ◽  
Pyroclastic Density Currents ◽  
Density Currents

Size-Dependence of Photoluminescence Property of ZnO Nanoparticles

2014 ◽  
Vol 887-888 ◽  
pp. 143-146 ◽  
Author(s):  
Xiao Fang Wang ◽  
Yun Liang Fang ◽  
Tian Le Li ◽  
Fu Juan Wang
Keyword(s):  
Grain Size ◽  
Lower Energy ◽  
Size Dependence ◽  
Surface States ◽  
Photoluminescence Property ◽  
Precipitation Method ◽  
Pl Spectra ◽  
Broadband Emission ◽  
Band Emission ◽  
20 Nm

Nanometer-sized ZnO crystals with the diameter from 20 nm to 110 nm were prepared by homogenous precipitation method (HPM). The photoluminescence (PL) spectra of as-prepared nanoparticles under excitation at the wavelength of 320 nm were detected. The PL spectra were fitted with Gaussian curves, in which a good fitting consisting of six Gaussian peaks was obtained. We observed that the multi-peak centers do not change much, while the relative amplitude of Gaussian combination to the band-to-band emission decreases rapidly with the increased grain size. It shows that the broadband emission at the lower energy is associated with the surface states.

The grain size dependence of flow stress in a Cu–26Ni–17Zn alloy

2000 ◽  
Vol 48 (8) ◽  
pp. 1807-1813 ◽  
Author(s):  
S. Nagarjuna ◽  
M. Srinivas ◽  
K.K. Sharma
Keyword(s):  
Grain Size ◽  
Flow Stress ◽  
Size Dependence
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