Insights into lava dome and spine extrusion using analogue sandbox experiments

2021 ◽  
Author(s):  
Edgar Zorn ◽  
Thomas Walter ◽  
Michael Heap ◽  
Ulrich Kueppers
Keyword(s):  
Lava Dome ◽  
Extrusion Process ◽  
Material Strength ◽  
Dome Growth ◽  
Common Process ◽  
New Material ◽  
Mechanical Factors ◽  
Sandbox Experiments ◽  
Analogue Experiments ◽  
Insight Into

<p>Lava dome formation is a common process at stratovolcanoes involving the shallow intrusion or extrusion of viscous lava and may lead to the rise of spines. Spines are protrusions observed to extrude episodically during lava dome growth, yet the structural and mechanical factors controlling their formation are only partially understood. Here, we provide new, detailed insight into lava dome growth and the production of spines using a novel set of analogue experiments extruding sand-plaster mixtures from a fixed-diameter conduit under isothermal conditions. We trace displacement and strain with photogrammetric methods for precise and detailed monitoring of the extrusion process. Results show initial dome growth forming a steep-sided and flat-topped shape through extrusion of new material, leading to slumping of oversteepening slopes, forming a talus. Spines are found to protrude at a later stage through the dome surface along discrete circular faults that originate from the conduit walls, starting a cycle of spine growth and collapse. As our spines only appear after prolonged extrusion, we relate their appearance to the compaction and strengthening of material within the conduit. We find that spine diameter, height and volume are positively correlated with increasing cohesion and therefore material strength. The spine diameter was also observed to be smaller or equal to the diameter of the underlying conduit, as shear extrusion occurs along vertical to outward-dipping fault planes. For natural domes, our findings imply that spine growth may be the consequence of compaction and densification via porosity loss, shearing and/or outgassing of conduit magma during ascent. More efficient compaction will yield wider and taller spines as a result of increasing rock strength. Our study further highlights the relevance of analogue experiments in the study of lava domes and spines, which remain one of the most hazardous and unpredictable features at dome-forming volcanoes worldwide.</p>

Mixture Ratio Design of Inorganic Polymer Concrete and the Study of Expansive Performance

2013 ◽  
Vol 357-360 ◽  
pp. 1142-1147 ◽  
Author(s):  
Li Ming Yu ◽  
Zhe An Lu ◽  
Xiao Hui Yuan ◽  
Hui Guo Chen
Keyword(s):  
Volume Growth ◽  
Inorganic Polymer ◽  
Polymer Concrete ◽  
Material Strength ◽  
Mixture Ratio ◽  
Engineering Research ◽  
Expansive Agent ◽  
New Material ◽  
Dry Shrinkage ◽  
Mixture Ratio Design

norganic polymer concrete of a new environment-friendly material has been the hot issue in engineering research so far. For this new material, the main job of the paper includes: we design mixture ratios of inorganic polymer concrete by ourselves, testing the concrete in the age periods of 3, 7, 28 d. The results indicate that this kind of material strength develops mainly in the first 3 d, the strength grows slowly in the later stage; the dry shrinkage of the configured concrete properties are measured, the curve of dry shrinkage shows that the dry shrinkage occurs mainly in the first 14 d and develops slowly in the late; And measure the expansion performance of the concrete member mixed the different categories expansive agent, the results show that the volume growth of mortar specimens to join HCSA expansion agent are obvious; Test results provide a certain basis for the inorganic polymer concrete of micro expansion.

scholarly journals Understanding the Role of Shape and Composition of Star-Shaped Polymers and their Ability to Both Bind and Prevent Bacteria Attachment on Oral Relevant Surfaces

2019 ◽  
Vol 10 (4) ◽  
pp. 56 ◽  
Author(s):  
Hamid Mortazavian ◽  
Guillaume A. Picquet ◽  
Jānis Lejnieks ◽  
Lynette A. Zaidel ◽  
Carl P. Myers ◽  
...  
Keyword(s):  
Bacterial Adhesion ◽  
Oral Care ◽  
Oral Bacteria ◽  
New Material ◽  
Polymer Shape ◽  
Dental Applications ◽  
Insight Into ◽  
Structural Aspects

In this study, we have prepared a series of 4- and 6-arm star-shaped polymers with varying molecular weight and hydrophobicity in order to provide insight into the role and relationship that shape and composition have on the binding and protecting of oral relevant surfaces (hydroxyapatite, HAP) from bacteria colonization. Star-shaped acrylic acid polymers were prepared by free-radical polymerization in the presence of chain transfer agents with thiol groups, and their binding to the HAP surfaces and subsequent bacteria repulsion was measured. We observed that binding was dependent on both polymer shape and hydrophobicity (star vs. linear), but their relative efficacy to reduce oral bacteria attachment from surfaces was dependent on their hydrophobicity only. We further measured the macroscopic effects of these materials to modify the mucin-coated HAP surfaces through contact angle experiments; the degree of angle change was dependent on the relative hydrophobicity of the materials suggesting future in vivo efficacy. The results from this study highlight that star-shaped polymers represent a new material platform for the development of dental applications to control bacterial adhesion which can lead to tooth decay, with various compositional and structural aspects of materials being vital to effectively design oral care products.

scholarly journals Caenagnathids of the Dinosaur Park Formation (Campanian) of Alberta, Canada: anatomy, osteohistology, taxonomy, and evolution

2020 ◽  
Vol 8 ◽  
pp. 105-153 ◽  
Author(s):  
Gregory Funston
Keyword(s):  
Body Size ◽  
Skeletal Maturity ◽  
Niche Overlap ◽  
Niche Space ◽  
The Past ◽  
Adult Body ◽  
New Material ◽  
Taxonomic Framework ◽  
Dinosaur Park Formation ◽  
Insight Into

Our understanding of caenagnathid anatomy, diversity, and ecology has improved considerably in the past twenty years, but numerous issues still remain. Among these, the diversity and taxonomy of caenagnathids from the Dinosaur Park Formation of Alberta, Canada, have remained problematic. Whereas some authors recognize three genera, others suggest only two were present, and there is considerable disagreement about which specimens are referable to which genus. This study aims to resolve this issue by reviewing the known specimens and using osteohistology, to establish a testable taxonomic framework of Dinosaur Park Formation caenagnathids. Numerous new specimens from all regions of the skeleton provide insight into morphological variation in caenagnathids, and three morphotypes are recognized based on a combination of morphological features and body size. Osteohistology shows that representatives in each body size class are at skeletal maturity, and therefore supports the delineation of three taxa: the smaller Citipes elegans gen. nov., the intermediate Chirostenotes pergracilis, and the larger Caenagnathus collinsi, new material of which shows it rivalled Anzu wyliei in size. However, these analyses also raise concerns about the referral of isolated material to each taxon in the absence of skeletal overlap between specimens or osteohistological analysis. Caenagnathids are consistently recovered throughout the Dinosaur Park Formation interval, and two geographic clusters of increased abundance probably reflect collection and taphonomic biases. The coexistence of three taxa was apparently facilitated by differences in both adult body size and functional morphology of the dentary and pes, which suggests that caenagnathids minimized niche overlap rather than subdividing niche space. Regardless, little is known of the exact roles caenagnathids played in Late Cretaceous ecosystems. Incorporation of the new material and taxonomic framework into a phylogenetic analysis drastically improves our understanding of the relationships between caenagnathines, and sheds light on the evolution of body size in caenagnathids and its role in their diversification.

On lava dome growth, with application to the 1979 lava extrusion of the soufrière of St. Vincent

1982 ◽  
Vol 14 (3-4) ◽  
pp. 199-222 ◽  
Author(s):  
Herbert E. Huppert ◽  
John B. Shepherd ◽  
R. Haraldur Sigurdsson ◽  
Stephen J. Sparks
Keyword(s):  
Lava Dome ◽  
Dome Growth

Using the level set method to model endogenous lava dome growth

2007 ◽  
Vol 112 (B3) ◽  
Author(s):  
A. J. Hale ◽  
L. Bourgouin ◽  
H. B. Mühlhaus
Keyword(s):  
Level Set Method ◽  
Level Set ◽  
Lava Dome ◽  
Dome Growth

Growth and Characterization of Inas Quantum Dots on Silicon

1999 ◽  
Vol 583 ◽  
Author(s):  
L. Hansen ◽  
A. Ankudinov ◽  
F. Bensing ◽  
J. Wagner ◽  
G. Ade ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
The Other ◽  
Material System ◽  
Inas Quantum Dots ◽  
New Material ◽  
The One ◽  
Insight Into

AbstractUp to 1011 cm−2 InAs quantum dots (QD) can be grown on Silicon(001) by molecular beam epitaxy. This very new material system is on the one hand interesting with regard to the integration of optoelectronics with silicon technology on the other hand it offers new insight into the formation of QDs. We report on RHEED, TEM and Raman studies about (in-) coherence of the QDs and on an according to our knowledge so far unknown dewetting transition in this material system. The results are being discussed on the basis of a thermodynamic model, assuming a liquid-like behavior of a strained adlayer.

Photogrammetric monitoring of lava dome growth during the 2009 eruption of Redoubt Volcano

2013 ◽  
Vol 259 ◽  
pp. 308-316 ◽  
Author(s):  
Angela K. Diefenbach ◽  
Katharine F. Bull ◽  
Rick L. Wessels ◽  
Robert G. McGimsey
Keyword(s):  
Lava Dome ◽  
Dome Growth

Ultimate Strength of the Adventitia and Media of Human Atherosclerotic Carotid Arteries in the Axial and Circumferential Directions

2009 ◽  
Author(s):  
Zhongzhao Teng ◽  
Allen H. Hoffman ◽  
Jie Zheng ◽  
Pamela K. Woodard ◽  
Dalin Tang
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Atherosclerotic Plaque ◽  
Balloon Angioplasty ◽  
Cardiovascular Events ◽  
Computational Models ◽  
Carotid Arteries ◽  
Material Strength ◽  
Rupture Mechanism ◽  
Insight Into

The abrupt closure of an artery by an occlusive thrombus is the main cause of myocardial infarcts and other thrombotic sequelae of atherosclerosis. This thrombosis is often associated with rupture of an atherosclerotic plaque [1,2]. Histology has shown that most rupture sites are also sites of increased mechanical stress [2]. It has been widely accepted that atherosclerosis leads to locally increased stresses in the region of lesions. However, validation of this hypothesis has been impeded by a lack of experimental data on the material strength of atherosclerotic tissues. Knowledge of mechanical properties of human atherosclerotic tissues is essential for understanding the rupture mechanism and also for creating more accurate computational models for predicting fatal cardiovascular events [3]. Moreover, an increased understanding of the mechanical properties of atherosclerotic tissue is important for developing greater insight into the pathophysiology of the cardiovascular system and as well as for predicting the outcome of interventional treatments such as balloon angioplasty.

scholarly journals Load Stress Controls on Directional Lava Dome Growth at Volcán de Colima, Mexico

2019 ◽  
Vol 7 ◽  
Author(s):  
Edgar U. Zorn ◽  
Nicolas Le Corvec ◽  
Nick R. Varley ◽  
Jacqueline T. Salzer ◽  
Thomas R. Walter ◽  
...  
Keyword(s):  
Lava Dome ◽  
Volcán De Colima ◽  
Dome Growth ◽  
Volcan De Colima

Intestinal Development

Development ◽  
1958 ◽  
Vol 6 (3) ◽  
pp. 403-411
Author(s):  
Alfred J. Coulombre ◽  
Jane L. Coulombre
Keyword(s):  
Chick Embryo ◽  
Adult Stage ◽  
Intestinal Development ◽  
Geometric Form ◽  
Adult Form ◽  
Intermediate Period ◽  
Mechanical Factors ◽  
Intestinal Morphogenesis ◽  
Insight Into

The work of D'Arcy Thompson is a classic example of the insight into morphogenesis that may be gained by a thoughtful consideration of adult form. Even greater insight into the factors underlying morphogenesis might accrue from a detailed study, not only of the adult stage, but also of the intermediate period of development. An attack at this level would, at the very least, yield an account of events whose ordering in time would suggest certain causal sequences and exclude others. Many organs reveal strikingly simple changes in geometric form during development. These structures provide an opportunity to investigate the role of various factors in the genesis of adult form. We have selected one such organ, the duodenum of the chick embryo, for a series of investigations into the role of mechanical factors in intestinal morphogenesis.

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