scholarly journals Halophila Balfourii Solereder (Hydrocharitaceae)—An Overlooked Seagrass Species

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1614 ◽  
Author(s):  
John Kuo
Keyword(s):  
Electron Microscope ◽  
Indian Ocean ◽  
Optical Microscope ◽  
Seagrass Species ◽  
Leaf Epidermis ◽  
Halophila Stipulacea ◽  
The Indian Ocean ◽  
Independent Species ◽  
Seed Testa ◽  
Scanning Electron

Halophila balfourii Solereder has long been treated as a synonym of Halophila stipulacea (Forrsk.) Asch., although it was named more than a century ago. Microscopic (optical microscope and scanning electron microscope) studies on all available herbarium materials of these two species have reconfirmed that the unique papillose leaf epidermis is only presented in H. balfourii but not in H. stipulacea. The pattern of seed testa reticulate is significantly different between these two species. Furthermore, H. balfourii is predominately restricted to the Rodriguez and Mauritius Islands while membranous leafed H. stipulacea is widely distributed in the Red Sea, the Indian Ocean and the Mediterranean Sea as well as East Africa coasts. Based on distinctive characteristics of the leaf and seed coat, and its geographic distribution, it is recommended to reinstate H. balfourii as an independent species and not as a synonym of H. stipulacea.

Organoclay-reinforced polyethersulfone-modified epoxy-based hybrid nanocomposites

2011 ◽  
Vol 23 (7) ◽  
pp. 526-534 ◽  
Author(s):  
Yang Wang ◽  
Boming Zhang ◽  
Jinrui Ye
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Electron Microscope ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Hybrid Nanocomposites ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Modified Epoxy ◽  
Scanning Electron

Hybrid nanocomposites were successfully prepared by the incorporation of polyethersulfone (PES) and organoclay into epoxy resin. They had higher fracture toughness than the prepared PES/epoxy blend and organoclay/epoxy nanocomposites. The microstructures of the hybrid nanocomposites were studied. They were comprised of homogeneous PES/epoxy semi-interpenetrating network (semi-IPN) matrices and organoclay micro-agglomerates made up of tactoid-like regions composed of ordered exfoliated organoclay with various orientations. The former was confirmed with dynamic mechanical analysis, scanning electron microscopy and transmission electron microscopy, while the latter was successfully observed with X-ray diffraction measurements, optical microscope, scanning electron microscope and transmission electron microscope. The improvement of their fracture toughness was due to the synergistic toughening effect of the PES and the organoclay and related to their microstructures.

Effect of Casting Overheat and Rolling Temperature on Morphology of Sulfide in 30MnVS Steel

2012 ◽  
Vol 457-458 ◽  
pp. 270-273
Author(s):  
Yi You Tu ◽  
Guo Zhong Li
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Continuous Casting ◽  
Optical Microscope ◽  
Rolling Temperature ◽  
Ferrite Content ◽  
Continuous Casting Slab ◽  
Intragranular Ferrite ◽  
Sulfide Segregation ◽  
Scanning Electron

Effect of superheat and initial rolling temperature on the morphology and distribution of sulfide in non quenched and tempered free cutting steel 30MnVS has been studied by optical microscope and scanning electron microscope. Results show that proper superheat and initial rolling temperature can turn rod-shaped sulfide into massive or globular sulfide，to alleviate sulfide segregation and pro-eutectoid ferrite distribution along the boundary of pearlite clusters in 30MnVS , increase the intragranular ferrite content and optimize the structure of continuous casting slab.

Analysis of an Axle Failure under Torsional Load

2016 ◽  
Vol 850 ◽  
pp. 101-106 ◽  
Author(s):  
Shu Mei Li ◽  
Jian Jun Yang ◽  
Wei Dong Zhang ◽  
August Chang ◽  
Cai Xia Zhang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Failure Mechanism ◽  
Field Testing ◽  
Optical Microscope ◽  
Fatigue Lifetime ◽  
Torsional Load ◽  
Torsional Fatigue ◽  
Secondary Cracks ◽  
Scanning Electron

Premature fracture of an axle under torsional load occurred after a tracked military tank had experienced field testing for only 80 kilometers. Visual metallographic examinations were performed with optical microscope (OM) and scanning electron microscope (SEM). The investigation demonstrates that the premature fracture is caused by metallurgical problems inside the axle where the primary and secondary cracks originate, propagate, and eventually result in final catastrophic rupture through torsional fatigue. The failure mechanism is summarized and improvement of the fatigue lifetime for the axle is recommended.

Investigation on the Microstructure Hardness for the Hot Compressed Duplex Steel

2022 ◽  
Vol 905 ◽  
pp. 30-37
Author(s):  
Shu Lan Zhang ◽  
Xiao Dan Zhang ◽  
Hai Feng Xu ◽  
Chang Wang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Optical Microscope ◽  
Ferrite Phase ◽  
Ferrite Formation ◽  
Average Hardness ◽  
Duplex Steel ◽  
Quench Temperature ◽  
Fluctuation Range ◽  
Scanning Electron

Effect of microstructure size and type on the hardness for the duplex steel were disclosed by using of optical microscope (OM), scanning electron microscope (SEM) and nanoindenter for the samples hot compressed under different temperature with reduction of 10%, 30%, 50% and 70%. OM and SEM were used to measure the average martensite lamellar width, space and indenter morphology. nanoindenter test characterized the microstructure hardness for the samples under different process. Experiment results show that martensite hardness for the sample hot compressed at 950°C has larger diversity than that of sample hot compressed at 1200°C. The martensite hardness fluctuation range for the sample compressed at 950°C is almost from about 7GPa to 12GPa, while, for the sample compressed at 1200°C, the fluctuation range is basically from about 9GPa to 12GPa. However, the average hardness for the samples hot compressed at 950°C is comparably smaller, which is related with lower quench temperature. The larger martensite hardness fluctuation is mainly related with induced ferrite formation and finer martensite lamellar width. For the ferrite phase, the hardness fluctuation range is lower.

CHARACTERISATION OF BIOMEDICAL TITANIUM LAYERS DEPOSITED BY A VACUUM PLASMA SPRAY PROCESS

2021 ◽  
Vol 55 (2) ◽  
pp. 231-235
Author(s):  
Mihailo Mrdak ◽  
Darko Bajić ◽  
Darko Veljić ◽  
Marko Rakin
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Hardness Test ◽  
Optical Microscope ◽  
Mechanical Tests ◽  
Test Method ◽  
Bonding Layer ◽  
Vacuum Plasma Spray ◽  
Porous Ti ◽  
Scanning Electron

In this paper we will describe the process of the deposition of thick layers of VPS-Ti coating, which is used as a bonding layer for the upper porous Ti coatings on implant substrates. In order to deposit the powder, we used HÖGANÄS Ti powder labelled as AMPERIT 154.086 -63 µm. In order to test the mechanical properties and microstructure of the VPS-Ti coating, the powder was deposited on Č.4171 (X15Cr13 EN10027) steel substrates. Mechanical tests of the microhardness of the coating were performed by the Vickers hardness test method (HV0.3) and tensile strength by measuring the force per unit area (MPa). The microhardness of the coating is 159 HV0.3, which is consistent with the microstructure. The coating was found to have a good bond strength of 68 MPa. The morphology of the powder particles was examined on a scanning electron microscope. The microstructure of the coating, both when deposited and etched, was examined with an optical microscope and a scanning electron microscope. By etching the coating layers, it was found that the structure is homogeneous and that it consists of a mixture of low-temperature and high-temperature titanium phases (α-Ti + β-Ti). Our tests have shown that the deposited layers of Ti coating can be used as a bonding layer for porous Ti coatings in the production of implants.

scholarly journals Enhancing the Mechanical Properties of Hot Roll Bonded Al/Ti Laminated Metal Composites (LMCs) by Pre-Rolling Diffusion Process

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 795 ◽  
Author(s):  
Cheng Zhang ◽  
Shouxin Wang ◽  
Hanxue Qiao ◽  
Zejun Chen ◽  
Taiqian Mo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Diffusion Process ◽  
Energy Dispersive Spectrometer ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Interfacial Structure ◽  
Metal Composites ◽  
Diffusion Temperature ◽  
Scanning Electron

In this study, the traditional hot rolling to fabricate Al/Ti laminated metal composites (LMCs) was improved by using a pre-rolling diffusion process. The effect of the pre-rolling diffusion on microstructure and mechanical properties of Al/Ti LMCs were investigated by various methods, such as optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and tensile tests. The results show that, with increasing diffusion temperature, the thickness in diffusion layer was increased and the mechanical properties of LMCs were improved obviously, which was attributed to the optimized interfacial structure after diffusion process. In addition, the formation of TiAl3 intermetallic compounds (IMCs) was detected in the bonding interface, which played an important role in improving the mechanical properties for Al/Ti LMCs. The predicted results of stress-strain curves from rule of mixture (ROM) indicated that, there existed an extra interfacial strengthening in Al/Ti LMCs beside the mechanical properties provided by the contribution of constituent layers. The pre-rolling diffusion process is effective for the optimization of interfacial structure and improvement of mechanical properties in Al/Ti LMCs.

scholarly journals Grinding Test on Tremolite with Fibrous and Prismatic Habit

Fibers ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 52 ◽  
Author(s):  
Oliviero Baietto ◽  
Mariangela Diano ◽  
Giovanna Zanetti ◽  
Paola Marini
Keyword(s):  
Electron Microscope ◽  
Phase Contrast ◽  
Health And Safety ◽  
Optical Microscope ◽  
Diameter Ratio ◽  
Grinding Process ◽  
Identification Procedure ◽  
Dimensional Parameter ◽  
Before And After ◽  
Scanning Electron

The main objective of this work is the evaluation of the morphology change in tremolite particles before and after a grinding process. The crushing action simulates anthropic alteration of the rock, such as excavation in rocks containing tremolite during a tunneling operation. The crystallization habit of these amphibolic minerals can exert hazardous effects on humans. The investigated amphibolic minerals are four tremolite samples, from the Piedmont and Aosta Valley regions, with different crystallization habits. The habits can be described as asbestiform (fibrous) for longer and thinner fibers and non-asbestiform (prismatic) for prismatic fragments, also known as “cleavage” fragments. In order to identify the morphological variation before and after the grinding, both a phase contrast optical microscope (PCOM) and a scanning electron microscope (SEM) were used. The identification procedure for fibrous and prismatic elements is related to a dimensional parameter (length–diameter ratio) defined by the Health and Safety Executive. The results highlight how mineral comminution leads to a rise of prismatic fragments and, therefore, to a potentially safer situation for worker and inhabitants.

Micromachining of Metals, Alloys and Ceramics by Picosecond Laser Ablation

2008 ◽  
Author(s):  
Wenqian Hu ◽  
Galen B. King ◽  
Yung C. Shin
Keyword(s):  
Electron Microscope ◽  
Laser Ablation ◽  
Picosecond Laser ◽  
Ablation Rate ◽  
Optical Microscope ◽  
Recast Layer ◽  
Laser Machining ◽  
Percussion Drilling ◽  
Scanning Electron

Microhole drilling and microstructure machining with a picosecond (ps) Nd:YVO4 laser (pulse duration of 10 ps) in metals, alloys and ceramics are reported. Blind and through microholes were drilled by percussion drilling as well as trepanning drilling. The diameters of the holes were in the range from 20 μm to 1000 μm. Microfeatures were machined and the flexibility of ps laser machining was demonstrated. The quality of drilled holes, e.g., recast layer, microcrack and conicity, and that of the microstructures, were investigated by optical microscope, surface profilometer, or scanning electron microscope (SEM). Ps laser ablation rate was investigated by experiments as well as a simplified laser ablation model.

Vehicle Driving Axle Half Shaft Fracture Analysis

2014 ◽  
Vol 912-914 ◽  
pp. 658-661
Author(s):  
Jun Jie Wang
Keyword(s):  
Electron Microscope ◽  
Fatigue Strength ◽  
Shaft Fracture ◽  
Fracture Analysis ◽  
Optical Microscope ◽  
Automobile Driving ◽  
Quenching Temperature ◽  
Torsional Fatigue ◽  
Conditioning Treatment ◽  
Scanning Electron

by using optical microscope and scanning electron microscope (sem), for minitype automobile driving axle half shaft fracture piece of organization and the fracture characteristic is analyzed and the results show that the axle shaft of conditioning treatment in the quenching temperature high enough, make its surface and center organization exists in the group more ferrite, caused the artifacts of the final hardness and fatigue strength is insufficient, led to the use of half shaft torsional fatigue fracture.

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