Special Issue on Precision Surface Finishing

2019 ◽  
Vol 13 (2) ◽  
pp. 173-173
Author(s):  
Fang-Jung Shiou ◽  
Toshiyuki Enomoto
Keyword(s):  
Narrow Channel ◽  
High Energy ◽  
Surface Finishing ◽  
Special Issue ◽  
Surface Machining ◽  
Energy Beam ◽  
Recent Developments ◽  
Ultrasonic Assisted ◽  
Single Crystal Sic ◽  
Finishing Processes

Precision surface finishing plays an important role in product quality owing to its direct effects on product appearance. As a result, automated precision surface finishing processes (APSFPs) are key technologies for industrial products and molds for forming and shaping processes. APSFPs can be divided into three main categories, namely, mechanical processes, electrochemical processes, and high energy beam processes. The objective of this special issue is to collect the cutting-edge research works focused on APSFPs. This issue includes 11 papers on APSFPs covering the following topics: ===danraku===- Review of ultraprecision surface finishing processes. ===danraku===- Ultraprecision surface machining and finishing with compensated feeding mechanisms. ===danraku===- Ultrasonic assisted cutting of unidirectional wetting surfaces and polishing of mold steels. ===danraku===- Vibration-assisted polishing of glass lenses. ===danraku===- Magnetic-assisted polishing of mirror surfaces. ===danraku===- Chemical-mechanical polishing of single-crystal SiC and GaN wafers. ===danraku===- Direct transfer of smoothing Au surfaces. ===danraku===- Plasma surface finishing of narrow channel walls of X-ray crystal monochromators. ===danraku===- Analysis and characterization of finished surfaces. It is expected that this issue will be helpful for readers to understand the recent developments in APSFPs and will lead to further research on APSFPs. We deeply appreciate the contributions of all authors and thank the reviewers for their incisive efforts.

scholarly journals Review of Superfinishing by the Magnetic Abrasive Finishing Process

2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Lida Heng ◽  
Yon Jig Kim ◽  
Sang Don Mun
Keyword(s):  
High Surface ◽  
Processing Parameters ◽  
Engineering Industry ◽  
Advanced Materials ◽  
Surface Finishing ◽  
Magnetic Abrasive Finishing ◽  
Surface Finishes ◽  
Abrasive Finishing ◽  
Recent Developments ◽  
Finishing Processes

AbstractRecent developments in the engineering industry have created a demand for advanced materials with superior mechanical properties and high-quality surface finishes. Some of the conventional finishing methods such as lapping, grinding, honing, and polishing are now being replaced by non-conventional finishing processes. Magnetic Abrasive Finishing (MAF) is a non-conventional superfinishing process in which magnetic abrasive particles interact with a magnetic field in the finishing zone to remove materials to achieve very high surface finishing and deburring simultaneously. In this review paper, the working principles, processing parameters, and current limitations for the MAF process are examined via reviewing important work in the literature. Additionally, future developments of the MAF process are discussed.

Characterization of thermal barrier coatings formed by electon-beam physical vapor deposition (EB-PVD)

1989 ◽  
Vol 47 ◽  
pp. 426-427
Author(s):  
Ozer Unal
Keyword(s):  
Thermal Barrier Coatings ◽  
Physical Vapor Deposition ◽  
Ceramic Coating ◽  
High Vacuum ◽  
Ceramic Coatings ◽  
High Energy ◽  
Thermal Barrier ◽  
Protective Oxide ◽  
Barrier Coatings ◽  
Energy Beam

Interest in ceramics as thermal barrier coatings for hot components of turbine engines has increased rapidly over the last decade. The primary reason for this is the significant reduction in heat load and increased chemical inertness against corrosive species with the ceramic coating materials. Among other candidates, partially-stabilized zirconia is the focus of attention mainly because ot its low thermal conductivity and high thermal expansion coefficient.The coatings were made by Garrett Turbine Engine Company. Ni-base super-alloy was used as the substrate and later a bond-coating with high Al activity was formed over it. The ceramic coatings, with a thickness of about 50 μm, were formed by EB-PVD in a high-vacuum chamber by heating the target material (ZrO2-20 w/0 Y2O3) above its evaporation temperaturef >3500 °C) with a high-energy beam and condensing the resulting vapor onto a rotating heated substrate. A heat treatment in an oxidizing environment was performed later on to form a protective oxide layer to improve the adhesion between the ceramic coating and substrate. Bulk samples were studied by utilizing a Scintag diffractometer and a JEOL JXA-840 SEM; examinations of cross-sectional thin-films of the interface region were performed in a Philips CM 30 TEM operating at 300 kV and for chemical analysis a KEVEX X-ray spectrometer (EDS) was used.

The promises and perfidy of cryomicroscopy and analysis

1994 ◽  
Vol 52 ◽  
pp. 382-383
Author(s):  
Patrick Echlin
Keyword(s):  
Low Temperature ◽  
High Energy ◽  
Short Paper ◽  
List Type ◽  
Time Resolved ◽  
Energy Beam ◽  
Cellular Analysis ◽  
Dissolved Ions ◽  
Embedding Medium ◽  
Low Temperature Microscopy

The unusual title of this short paper and its accompanying tutorial is deliberate, because the intent is to investigate the effectiveness of low temperature microscopy and analysis as one of the more significant elements of the less interventionist procedures we can use to prepare, examine and analyse hydrated and organic materials in high energy beam instruments. The promises offered by all these procedures are well rehearsed and the litany of petitions and responses may be enunciated in the following mantra.Vitrified water can form the perfect embedding medium for bio-organic samples.Frozen samples provide an important, but not exclusive, milieu for the in situ sub-cellular analysis of the dissolved ions and electrolytes whose activities are central to living processes.The rapid conversion of liquids to solids provides a means of arresting dynamic processes and permits resolution of the time resolved interactions between water and suspended and dissolved materials.The low temperature environment necessary for cryomicroscopy and analysis, diminish, but alas do not prevent, the deleterious side effects of ionizing radiation.Sample contamination is virtually eliminated.

scholarly journals High energy storage MnO2@C fabricated by ultrasonic-assisted stepwise electrodeposition and vapor carbon coating

2021 ◽  
Vol 6 ◽  
pp. 100098
Author(s):  
Ming Zhang ◽  
Dandan Jin ◽  
Liu Zhang ◽  
Xumei Cui ◽  
Zhi Zhang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Carbon Coating ◽  
High Energy ◽  
Ultrasonic Assisted ◽  
High Energy Storage

scholarly journals Introduction to the Special Issue “Radiative Transfer in the Earth Atmosphere”

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 479
Author(s):  
Irina Sokolik
Keyword(s):  
Radiative Transfer ◽  
Earth Atmosphere ◽  
Special Issue ◽  
The Earth ◽  
Radiative Impact ◽  
Different Types ◽  
Recent Developments

This Special Issue aims at addressing the recent developments towards improving our understanding of the diverse radiative impact of different types of aerosols and clouds [...]

scholarly journals Special Issue on Nanoscale Thermodynamics

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 584
Author(s):  
Signe Kjelstrup
Keyword(s):  
Energy Conversion ◽  
Special Issue ◽  
Recent Developments

This Special Issue concerns recent developments of a theory for energy conversion on the nanoscale, namely nanothermodynamics [...]

scholarly journals The Growth of Semiconductor Thin Films Studied by RHEED

1990 ◽  
Vol 43 (5) ◽  
pp. 583
Author(s):  
GL Price
Keyword(s):  
Thin Films ◽  
Surface Science ◽  
High Vacuum ◽  
High Energy ◽  
Ultra High Vacuum ◽  
Large Area ◽  
Growth Modes ◽  
Semiconductor Thin Films ◽  
Wide Range ◽  
Recent Developments

Recent developments in the growth of semiconductor thin films are reviewed. The emphasis is on growth by molecular beam epitaxy (MBE). Results obtained by reflection high energy electron diffraction (RHEED) are employed to describe the different kinds of growth processes and the types of materials which can be constructed. MBE is routinely capable of heterostructure growth to atomic precision with a wide range of materials including III-V, IV, II-VI semiconductors, metals, ceramics such as high Tc materials and organics. As the growth proceeds in ultra high vacuum, MBE can take advantage of surface science techniques such as Auger, RHEED and SIMS. RHEED is the essential in-situ probe since the final crystal quality is strongly dependent on the surface reconstruction during growth. RHEED can also be used to calibrate the growth rate, monitor growth kinetics, and distinguish between various growth modes. A major new area is lattice mismatched growth where attempts are being made to construct heterostructures between materials of different lattice constants such as GaAs on Si. Also described are the new techniques of migration enhanced epitaxy and tilted superlattice growth. Finally some comments are given On the means of preparing large area, thin samples for analysis by other techniques from MBE grown films using capping, etching and liftoff.

scholarly journals Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3193
Author(s):  
Ana L. Santos ◽  
Maria-João Cebola ◽  
Diogo M. F. Santos
Keyword(s):  
Energy Content ◽  
Water Electrolysis ◽  
High Energy ◽  
Operating Conditions ◽  
Energy Sources ◽  
Alkaline Water Electrolysis ◽  
Alkaline Water ◽  
New Energy ◽  
Recent Developments ◽  
Cell Components

Environmental issues make the quest for better and cleaner energy sources a priority. Worldwide, researchers and companies are continuously working on this matter, taking one of two approaches: either finding new energy sources or improving the efficiency of existing ones. Hydrogen is a well-known energy carrier due to its high energy content, but a somewhat elusive one for being a gas with low molecular weight. This review examines the current electrolysis processes for obtaining hydrogen, with an emphasis on alkaline water electrolysis. This process is far from being new, but research shows that there is still plenty of room for improvement. The efficiency of an electrolyzer mainly relates to the overpotential and resistances in the cell. This work shows that the path to better electrolyzer efficiency is through the optimization of the cell components and operating conditions. Following a brief introduction to the thermodynamics and kinetics of water electrolysis, the most recent developments on several parameters (e.g., electrocatalysts, electrolyte composition, separator, interelectrode distance) are highlighted.

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