scholarly journals Brittle Behavior in Aspirin Crystals: Evidence of Spalling Fracture

2021 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza
Keyword(s):  
Spalling Fracture ◽  
Brittle Behavior

Survey of Relations of Chemical Constituents in Polymer-Based Materials with Brittleness and its Associated Properties

2016 ◽  
Vol 10 (4s) ◽  
pp. 595-600 ◽  
Author(s):  
Witold Brostow ◽  
◽  
Haley E. Hagg Lobland ◽  
Keyword(s):  
Chemical Composition ◽  
Impact Strength ◽  
Free Volume ◽  
Chemical Constituents ◽  
Polymer Processing ◽  
Brittle Behavior ◽  
Composition And Structure ◽  
Common Thread

The property of brittleness for polymers and polymer-based materials (PBMs) is an important factor in determining the potential uses of a material. Brittleness of polymers may also impact the ease and modes of polymer processing, thereby affecting economy of production. Brittleness of PBMs can be correlated with certain other properties and features of polymers; to name a few, connections to free volume, impact strength, and scratch recovery have been explored. A common thread among all such properties is their relationship to chemical composition and morphology. Through a survey of existing literature on polymer brittleness specifically combined with relevant reports that connect additional materials and properties to that of brittleness, it is possible to identify chemical features of PBMs that are connected with observable brittle behavior. Relations so identified between chemical composition and structure of PBMs and brittleness are described herein, advancing knowledge and improving the capacity to design new and to choose among existing polymers in order to obtain materials with particular property profiles.

Brittle Behaviour in Aspirin Crystals: Evidence of Spalling Fracture

2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Single Crystals ◽  
Spalling Fracture ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>

Brittle Behaviour in Aspirin Crystals: Evidence of Spalling Fracture

2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Single Crystals ◽  
Spalling Fracture ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>

scholarly journals Spalling fracture mechanism of granite subjected to dynamic tensile loading

2021 ◽  
Vol 31 (7) ◽  
pp. 2116-2127
Author(s):  
Lin-qi HUANG ◽  
Jun WANG ◽  
Aliakbar MOMENI ◽  
Shao-feng WANG
Keyword(s):  
Fracture Mechanism ◽  
Tensile Loading ◽  
Spalling Fracture ◽  
Dynamic Tensile Loading

scholarly journals Laboratory Study of the Ultraviolet Radiation Effect on an HDPE Geomembrane

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 390
Author(s):  
Fernando Luiz Lavoie ◽  
Marcelo Kobelnik ◽  
Clever Aparecido Valentin ◽  
Érica Fernanda da Silva Tirelli ◽  
Maria de Lurdes Lopes ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Morphological Changes ◽  
Field Performance ◽  
Melt Flow Index ◽  
Flow Index ◽  
Test Results ◽  
Upward Trend ◽  
Scanning Calorimetry ◽  
Ultraviolet Exposure ◽  
Brittle Behavior

High-density polyethylene (HDPE) geomembranes are polymeric geosynthetic materials usually applied as a liner in environmental facilities due to their good mechanical properties, good welding conditions, and excellent chemical resistance. A geomembrane’s field performance is affected by different conditions and exposures, including ultraviolet radiation, thermal and oxidative exposure, and chemical contact. This article presents an experimental study with a 1.0 mm-thick HDPE virgin geomembrane exposed by the Xenon arc weatherometer for 2160 h and the ultraviolet fluorescent weatherometer for 8760 h to understand the geomembrane’s behavior under ultraviolet exposure. The evaluation was performed using the melt flow index (MFI) test, oxidative-induction time (OIT) tests, tensile test, differential scanning calorimetry (DSC) analysis, and Fourier transform infrared spectroscopy (FTIR) analysis. The sample exposed in the Xenon arc equipment showed a tendency to increase the MFI values during the exposure time. This upward trend may indicate morphological changes in the polymer. The tensile behavior analysis showed a tendency of the sample to lose ductility, without showing brittle behavior. The samples’ OIT test results under both device exposures showed faster antioxidant depletion for the standard OIT test than the high-pressure OIT test. The DSC and FTIR analyses did not demonstrate the polymer’s changes.

Brittle-ductile transition: semi-brittle behavior

1989 ◽  
Vol 167 (1) ◽  
pp. 75-79 ◽  
Author(s):  
John V. Ross ◽  
Peter D. Lewis
Keyword(s):  
Brittle Behavior ◽  
Brittle Ductile Transition

A Discussion on Removal Mechanisms in Grinding Polycrystalline Diamond

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Florestan Schindler ◽  
Richard Brocker ◽  
Fritz Klocke ◽  
Patrick Mattfeld
Keyword(s):  
Material Removal ◽  
Polycrystalline Diamond ◽  
Material Removal Mechanism ◽  
Mesoscopic Scale ◽  
Tool Manufacture ◽  
Brittle Behavior ◽  
Process Characteristics ◽  
Chemical Effects ◽  
Removal Mechanisms ◽  
First Time

Polycrystalline diamond (PCD) grinding takes an important role in the field of tool manufacture. Regardless, there is still lack of process knowledge about the occurring material removal mechanisms in PCD grinding. In order to get a better understanding of the process characteristics, the surface integrity zone of PCD inserts has been analyzed in detail after grinding for the first time. The drawn conclusion questions solely ductile or brittle behavior as removal mechanisms. Both thermal and mechanical process loads during the grinding process lead to thermophysical and chemical effects on a micro- and mesoscopic-scale and might thus have a significant impact on the material removal mechanism.

scholarly journals Effect of Incorporation of Rice Husk Ash Instead of Cement on the Performance of Steel Fibers Reinforced Concrete

2021 ◽  
Vol 8 ◽  
Author(s):  
Osama Zaid ◽  
Jawad Ahmad ◽  
Muhammad Shahid Siddique ◽  
Fahid Aslam
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Steel Fibers ◽  
Concrete Compressive Strength ◽  
Brittle Behavior ◽  
Direct Combustion ◽  
Low Performance ◽  
Strength And Durability ◽  
Reference Samples

The production of rice is significant worldwide; the husk produced is generally used as a combustible material for the preparation of paddies, delivering energy through direct combustion as well as by gasifying. Annually, 7.4 million tons of Rice Husk Ash (RHA) is produced and poses an incredible danger to the environment, harming the land and the encompassing zone where it is unloaded. In the transformation of rice husk to ash, the ignition cycle eliminates the natural products, leaving silica-rich remains. These silica-rich remains have proven to have potential to be utilized in concrete as a limited substitution of cement to enhance the concrete compressive strength. Steel fibers’ incorporation increases the concrete tensile strength, balances out concrete samples, and changes their brittle behavior to a more ductile response. In the current study, the influence of various doses of Rice Husk Ash (RHA) used in concrete in the presence and absence of steel fibers and concrete performance has been examined. A total of nine mixes have been designed: one was a control, four were without steel fibers containing only RHA, and the last four mixed RHA with steel fibers from 0.5 to 2%. Tests with 5, 10, 15, and 20% percentages of RHA replacing the concrete have been targeted. Results have been compared with the reference samples and the reasonability of adding Rice Husk Ash to concrete has been studied. From the results, it was noted that about 10% of cement might be replaced with Rice Husk Ash mixed in with steel fibers with almost equal compressive strength. Replacing more than 15% of cement with RHA will produce concrete with a low performance in terms of strength and durability.

scholarly journals Anisotropy of Microstructure and Strength in Fiber Textured Molybdenum Alloys

1987 ◽  
Vol 7 (1) ◽  
pp. 1-10 ◽  
Author(s):  
T. Oyama ◽  
J. Wadsworth
Keyword(s):  
Grain Boundaries ◽  
Transverse Direction ◽  
Longitudinal Direction ◽  
Fiber Texture ◽  
Good Ductility ◽  
Fibre Texture ◽  
Brittle Behavior ◽  
Molybdenum Alloys

Molybdenum and molybdenum alloys exhibit brittle behavior in the transverse direction of wrought bar stock despite having good ductility in the longitudinal direction. This is believed to be due to the presence of cracked-carbide stringers on adversely oriented grain boundaries. In the present paper, the possible role of anisotropy in strength, as a result of the presence of a strong fiber texture, is investigated. It is concluded, both theoretically and experimentally, that anistropy in strength between the transverse and longitudinal direction of barstock containing a perfect fibre texture is not a factor promoting brittle behavior.

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