Hierarchical Microstructure of Tooth Enameloid in Two Lamniform Shark Species, Carcharias taurus and Isurus oxyrinchus

Shark tooth enameloid is a hard tissue made up of nanoscale fluorapatite crystallites arranged in a unique hierarchical pattern. This microstructural design results in a macroscopic material that is stiff, strong, and tough, despite consisting almost completely of brittle mineral. In this contribution, we characterize and compare the enameloid microstructure of two modern lamniform sharks, Isurus oxyrinchus (shortfin mako shark) and Carcharias taurus (spotted ragged-tooth shark), based on scanning electron microscopy images. The hierarchical microstructure of shark enameloid is discussed in comparison with amniote enamel. Striking similarities in the microstructures of the two hard tissues are found. Identical structural motifs have developed on different levels of the hierarchy in response to similar biomechanical requirements in enameloid and enamel. Analyzing these structural patterns allows the identification of general microstructural design principles and their biomechanical function, thus paving the way for the design of bioinspired composite materials with superior properties such as high strength combined with high fracture resistance.

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Atlantic Shortfin Mako: Chronicle of a Death Foretold?

Laws ◽

10.3390/laws10030052 ◽

2021 ◽

Vol 10 (3) ◽

pp. 52

Author(s):

Mercedes Rosello ◽

Juan Vilata ◽

Dyhia Belhabib

Keyword(s):

North Atlantic ◽

Law Of The Sea ◽

Commercial Fishing ◽

Shark Species ◽

Applicable Law ◽

Incidental Capture ◽

The North ◽

Isurus Oxyrinchus ◽

Shortfin Mako ◽

Ocean Region

This article outlines recent events concerning the conservation and management trajectory of a highly migratory shark species, the shortfin mako (Isurus oxyrinchus), in the North Atlantic, where it has been routinely captured recreationally and as part of commercial fishing operations alongside other species. Noting recent warnings concerning the high mortality of the species in this ocean region, and the threat of imminent population collapse, this article sets out a number of applicable law of the sea provisions, and carries out an evaluation of relevant measures for target and incidental capture species, discussing their applicability to the mako fishery. It also presents an analysis of regional and global governance actions taken to date by the international community and by individual actors, noting a number of shortfalls, and outlining potential responses.

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FERRIUM M54

Alloy Digest ◽

10.31399/asm.ad.sa0822 ◽

2018 ◽

Vol 67 (9) ◽

Keyword(s):

Fracture Toughness ◽

Stress Corrosion ◽

Stress Corrosion Cracking ◽

High Resistance ◽

High Strength ◽

Cost Effective ◽

High Fracture Toughness ◽

High Fracture ◽

Structural Applications ◽

Resistance To Stress

Abstract Ferrium M54 was designed to create a cost-effective, ultra high-strength, high-fracture toughness material with a high resistance to stress-corrosion cracking for use in structural applications. This datasheet provides information on composition, hardness, and tensile properties as well asfatigue. Filing Code: SA-822. Producer or source: QuesTek Innovations, LLC.

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Investigation into the Structural, Chemical and High Mechanical Reforms in B4C with Graphene Composite Material Substitution for Potential Shielding Frame Applications

Molecules ◽

10.3390/molecules26071921 ◽

2021 ◽

Vol 26 (7) ◽

pp. 1921

Author(s):

Ibrahim M. Alarifi

Keyword(s):

Composite Material ◽

Melting Point ◽

Boron Carbide ◽

High Strength ◽

Stir Casting ◽

High Fracture Toughness ◽

Chemical Compositions ◽

High Fracture ◽

Fabrication Procedure ◽

Standard Designs

In this work, boron carbide and graphene nanoparticle composite material (B4C–G) was investigated using an experimental approach. The composite material prepared with the two-step stir casting method showed significant hardness and high melting point attributes. Scanning electron microscopy (SEM), along with energy dispersive X-ray spectroscopy (EDS) analysis, indicated 83.65%, 17.32%, and 97.00% of boron carbide + 0% graphene nanoparticles chemical compositions for the C-atom, Al-atom, and B4C in the compound studied, respectively. The physical properties of all samples’ B4C–G like density and melting point were 2.4 g/cm3 density and 2450 °C, respectively, while the grain size of B4C–G was in the range of 0.8 ± 0.2 µm. XRD, FTIR, and Raman spectroscopic analysis was also performed to investigate the chemical compositions of the B4C–G composite. The molding press composite machine was a fabrication procedure that resulted in the formation of outstanding materials by utilizing the sintering process, including heating and pressing the materials. For mechanical properties, high fracture toughness and tensile strength of B4C–G composites were analyzed according to ASTM standard designs. The detailed analysis has shown that with 6% graphene content in B4C, the composite material portrays a high strength of 134 MPa and outstanding hardness properties. Based on these findings, it is suggested that the composite materials studied exhibit novel features suitable for use in the application of shielding frames.

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Additively manufactured high strength and ductility CrCoNi medium entropy alloy with hierarchical microstructure

Materials Science and Engineering A ◽

10.1016/j.msea.2021.141545 ◽

2021 ◽

pp. 141545

Author(s):

Bolun Han ◽

Chengcheng Zhang ◽

Kai Feng ◽

Zhuguo Li ◽

Xiancheng Zhang ◽

...

Keyword(s):

High Strength ◽

Hierarchical Microstructure ◽

Strength And Ductility

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Research on Titanium Alloys with High Toughness and High Damage Tolerance

Materials Science Forum ◽

10.4028/www.scientific.net/msf.618-619.97 ◽

2009 ◽

Vol 618-619 ◽

pp. 97-100

Author(s):

Yong Qing Zhao ◽

Heng Lei Qu ◽

Jun Chen

Keyword(s):

Damage Tolerance ◽

Rapid Development ◽

Crack Propagation Rate ◽

High Strength ◽

High Fracture Toughness ◽

Ti Alloy ◽

Chinese Market ◽

High Fracture ◽

High Toughness ◽

Ti Alloys

The recent shift in the design focus for aeroplanes from strength to damage tolerance has led to a subsequent shift in the focus of Ti alloy research. China first started to research Ti alloys with damage tolerance from the year 2000. The first product stemming from this research is a Ti alloy with high strength, high toughness and damage tolerance (TC21). TC21 exhibits high strength (UTS  1100MPa), high fracture toughness (K1c  70MPa.m1/2) and a low crack propagation rate (da/dN being similar to Ti-6-4 with  annealing). Another Ti alloy, named TC4-DT, has also been produced. It has moderate strength, along with high toughness and damage tolerance (UTS  900MPa, K1c  70MPa.m1/2, da/dN being similar to Ti-6-4 with  annealing). Both TC21 and TC4-DT are now undergoing rapid development, with the former alloy also being applied to a full scale aeronautical application. Both TC21 and TC4-DT have promising futures in the industry. They will be the main Ti alloys with damage tolerance utilised in the Chinese market.

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Growth and spatiotemporal distribution of juvenile shortfin mako (Isurus oxyrinchus) in the western and central North Pacific

Marine and Freshwater Research ◽

10.1071/mf14316 ◽

2015 ◽

Vol 66 (12) ◽

pp. 1176 ◽

Cited By ~ 14

Author(s):

M. Kai ◽

K. Shiozaki ◽

S. Ohshimo ◽

K. Yokawa

Keyword(s):

North Pacific ◽

Linear Models ◽

North Pacific Ocean ◽

Age Groups ◽

Growth Curves ◽

Growth Function ◽

Gaussian Mixture ◽

Isurus Oxyrinchus ◽

Shortfin Mako ◽

Central North Pacific

This paper presents an estimation of growth curves and spatiotemporal distributions of juvenile shortfin mako shark (Isurus oxyrinchus) in the western and central North Pacific Ocean using port sampling data collected from 2005 to 2013. The monthly length compositions show a clear transition of three modes in the size range of smaller than 150-cm precaudal length (PCL), which were believed to represent the growth of age-0 to age-2 classes, and they were then decomposed into age groups by fitting a Gaussian mixture distribution. Simulation data of lengths at monthly ages were generated from the mean and standard deviation of each distribution, and fit with a von Bertalanffy growth function. Parameters of the estimated growth curves for males and females were 274.4 and 239.4cm PCL for the asymptotic length and 0.19 and 0.25 year–1 for the growth coefficient indicating apparently faster growth than previously reported. Generalised linear models were applied to age-0 to explore the seasonal changes of PCL by area. They were born during late autumn and winter off the coast of north-eastern Japan, an area known to have relatively high productivity compared with other pelagic areas, and gradually expanded their habitat eastward and northward with the seasons as they grew.

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Age and growth of the shortfin mako (Isurus oxyrinchus) in the south-eastern Pacific off Chile

Marine and Freshwater Research ◽

10.1071/mf08125 ◽

2009 ◽

Vol 60 (5) ◽

pp. 394 ◽

Cited By ~ 16

Author(s):

Francisco Cerna ◽

Roberto Licandeo

Keyword(s):

Growth Parameters ◽

Eastern Pacific ◽

Age And Growth ◽

The South ◽

Age Classes ◽

Vertebral Centra ◽

South Eastern ◽

Isurus Oxyrinchus ◽

Shortfin Mako ◽

Longline Fisheries

The shortfin mako, Isurus oxyrinchus, is a large pelagic shark with a widespread global distribution. However, very little is known about most aspects of this species for the south-eastern Pacific. In the present paper, the age and growth parameters of the shortfin mako, caught by Chilean swordfish longline fisheries from 2004 to 2005, are reported. Ages were estimated by counting band-pairs from sections of vertebral centra from 547 individuals, ranging from 76 to 330 cm in total length (TL). Trends in the proportion of opaque edges for all ages combined and grouped into ages 0–6 and 7–26 years indicated that they are formed during summer and showed that annually, one band-pair is formed in the vertebrae of shortfin makos. Modal-progression analysis was used to verify the first three age classes (ages 0–2 years). For both sexes, the oldest estimated age was 25+ years. Von Bertalanffy growth parameters were estimated at L∞ = 325.29 cm TL, K = 0.076 year–1 and t0 = –3.18 years for females and L∞ = 296.60 cm TL, K = 0.087 year–1 and t0 = –3.58 years for males. The results indicated that this species is highly vulnerable to exploitation and, thus, urgent conservation measures are required.

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Plasma Arc Spraying of Cu-Ti-Zr-Ni Amorphous Alloys

Thermal Spray 2000: Proceedings from the International Thermal Spray Conference ◽

10.31399/asm.cp.itsc2000p0851 ◽

2000 ◽

Author(s):

D.J. Sordelet ◽

P. Huang ◽

M.F. Besser ◽

E. Lepecheva

Keyword(s):

Cross Sections ◽

Metallic Glasses ◽

High Strength ◽

Amorphous Structure ◽

High Fracture Toughness ◽

Arc Spraying ◽

Plasma Arc ◽

High Fracture ◽

Spray Coatings ◽

Sprayed Coatings

Abstract A brief feasibility study was performed to produce thermal spray coatings using gas atomized powders of Cu47Ti34-xZr11Ni8Six, where x=0 and 1. These alloys have previously been shown to be capable of forming metallic glasses having thick (1-2 cm) cross sections because they can be cooled from the melt at relatively low cooling rates (e.g., 100-102Ks-1). The properties of these metallic glasses include high strength, high elasticity and high fracture toughness. Amorphous plasma arc sprayed coatings were produced which were close in composition to the starting powders, and exhibited comparable glass transition and crystallization behavior. The amorphous structure of the as-sprayed coatings was used as a source for forming a range of partially devitrified and fully crystallized structures. The average hardness of the coatings increased from around 6 GPa to near 10 GPa as the degree of crystallization increased.

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