Self-Lubrication of Machining Tools in Dry via In-situ Formed Tribofilms

2005 ◽  
Vol 890 ◽  
Author(s):  
Tatsuhiko Aizawa ◽  
Shigeo Yamamoto ◽  
Taro Sumitomo
Keyword(s):  
Materials Science ◽  
Protective Coatings ◽  
Cutting Speed ◽  
Green Manufacturing ◽  
Dry Machining ◽  
Wide Range ◽  
In Situ Formation ◽  
Green Manufacturing Technology ◽  
Turning Test

ABSTRACTGreen manufacturing technology has become a significant innovative keyword to reduce the environmental burden and CO2 emission at the stage of manufacturing and production. In daily operations by machining, huge amount of lubricating oils and cleansing agents is wasted so that dry machining technology provides us a way to completely reduce these wastes. Among several candidates, self-lubrication via in-situ formation of lubricious oxide films is accommodated to protective coatings in order to attain low friction and wear state even at higher cutting speed range. Materials science of in-situ formed lubricious oxide tribofilms is stated with consideration of accommodation mechanism via the chlorine implantation. Mechanical characterization is made for evaluation on elasto-plastic deformation of lubricious oxides. Turning test is employed to evaluate dry machinability of various tools for wide range of cutting speed. Self-lubrication in dry machining is described both for bare WC and TiCN-coated WC tools with and without chlorine implantation. Precise microstructure analyses are made by using the laser microscope, EDS and XPS. In-situ formation of lubricous oxides proves that self-lubrication process takes place even in dry machining to reduce the flank wear and friction coefficient.

scholarly journals Experimental Parametric Relationships for Chip Geometry in Dry Machining of the Ti6Al4V Alloy

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1260 ◽  
Author(s):  
Yezika Sánchez Hernández ◽  
Francisco Trujillo Vilches ◽  
Carolina Bermudo Gamboa ◽  
Lorenzo Sevilla Hurtado
Keyword(s):  
Experimental Data ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Cutting Parameters ◽  
Ti6al4v Alloy ◽  
Geometric Parameters ◽  
Dry Machining ◽  
Wide Range ◽  
Parametric Relationships ◽  
Chip Geometry

The Ti6Al4V alloy is included in the group of difficult-to-cut materials. Segmented chips are generated for a wide range of cutting parameters. This kind of chip geometry leads to the periodic variation of machining forces, tool vibrations, and work part-tolerance inaccuracies. Therefore, the analysis of chip morphology and geometry becomes a fundamental machinability criterion. However, few studies propose experimental parametric relationships that allow predicting chip-geometry evolution as a function of cutting parameters. In this work, an experimental analysis of the influence of cutting speed and feed rate on various chip-geometric parameters in dry machining of the Ti6Al4V alloy was carried out. In addition, the chip morphology and chip microstructure were studied. A clear dependence of certain chip-geometric parameters on the cutting parameters studied was found. From the experimental data, several parametric relationships were developed. These relationships were able to predict the evolution of different geometric parameters as a function of cutting speed and feed, within the tested range of values. The differences between the proposed models and the experimental data were also highlighted. These parametric equations allowed quantifying the value of parameters in which the trend was clear.

scholarly journals TMAO regulates the rigidity of kinesin-propelled microtubules

2021 ◽  
Author(s):  
Tasrina Munmun ◽  
Arif Md. Rashedul Kabir ◽  
Kazuki Sada ◽  
Akira Kakugo
Keyword(s):  
Deep Sea ◽  
Materials Science ◽  
Persistence Length ◽  
Simple Strategy ◽  
Biomolecular Motors ◽  
Wide Range

AbstractWe demonstrate that the rigidity of the microtubules (MTs), propelled by kinesins in an in vitro gliding assay, can be modulated using the deep-sea osmolyte trimethylamine N-oxide (TMAO). By varying the concentration of TMAO in the gliding assay, the rigidity of the MTs is modulated over a wide range. By employing this approach, we are able to reduce the persistence length of MTs, a measure of MT rigidity, ∼8 fold using TMAO of the concentration of 1.5 M. The rigidity of gliding MTs can be restored by eliminating the TMAO from the gliding assay. This work offers a simple strategy to regulate the rigidity of kinesin-propelled MTs in situ and would widen the applications of biomolecular motors in nanotechnology, materials science, and bioengineering.

Aberration correction: zooming out to overview

2009 ◽  
Vol 367 (1903) ◽  
pp. 3859-3870 ◽  
Author(s):  
A. Howie
Keyword(s):  
Materials Science ◽  
Complex Structure ◽  
Chromatic Aberration ◽  
Aberration Correction ◽  
Contrast Imaging ◽  
Atomic Column ◽  
Wide Range ◽  
The Many

In the structural characterization of thin specimens by projection (atomic column) imaging, the revolutionary development of aberration-corrected electron microscopy has already brought significant improvements not only in spatial resolution but also in improved image contrast. Some highlights from the symposium are summarized. Despite the purchasing and operating costs as well as the demands they place on operator skills, a staggering number of these new microscopes has already been installed worldwide. Serious challenges, therefore, arise including the need to attract customers from a wide range of disciplines where complex structure problems may require the development of new imaging modes. The ability to image at large scattering angles may be useful in mitigating some of the many as-yet uncorrected delocalization mechanisms that then arise and are systematically identified here. Larger specimen volumes made possible by chromatic aberration correction will benefit the development of more relevant in situ observations, particularly in materials science and catalysis. With additional incorporation of phase shifting electrodes or other devices, these chromatic aberration correctors could also be important for efficient phase contrast imaging in easily damaged biological structures. For many of these formidable problems, earlier experience of the optical microscopy community may teach some lessons.

scholarly journals A versatile nanoreactor for complementary in situ X-ray and electron microscopy studies in catalysis and materials science

2019 ◽  
Vol 26 (5) ◽  
pp. 1769-1781 ◽  
Author(s):  
Yakub Fam ◽  
Thomas L. Sheppard ◽  
Johannes Becher ◽  
Dennis Scherhaufer ◽  
Heinz Lambach ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Materials Science ◽  
Functional Materials ◽  
Ambient Conditions ◽  
Zeolite Sample ◽  
X Ray ◽  
Fluorescence Measurements ◽  
Wide Range ◽  
Modular Platform

Two in situ `nanoreactors' for high-resolution imaging of catalysts have been designed and applied at the hard X-ray nanoprobe endstation at beamline P06 of the PETRA III synchrotron radiation source. The reactors house samples supported on commercial MEMS chips, and were applied for complementary hard X-ray ptychography (23 nm spatial resolution) and transmission electron microscopy, with additional X-ray fluorescence measurements. The reactors allow pressures of 100 kPa and temperatures of up to 1573 K, offering a wide range of conditions relevant for catalysis. Ptychographic tomography was demonstrated at limited tilting angles of at least ±35° within the reactors and ±65° on the naked sample holders. Two case studies were selected to demonstrate the functionality of the reactors: (i) annealing of hierarchical nanoporous gold up to 923 K under inert He environment and (ii) acquisition of a ptychographic projection series at ±35° of a hierarchically structured macroporous zeolite sample under ambient conditions. The reactors are shown to be a flexible and modular platform for in situ studies in catalysis and materials science which may be adapted for a range of sample and experiment types, opening new characterization pathways in correlative multimodal in situ analysis of functional materials at work. The cells will presently be made available for all interested users of beamline P06 at PETRA III.

In Situ Synchrotron Radiation Research in Materials Science

MRS Bulletin ◽  
1999 ◽  
Vol 24 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Pedro A. Montano ◽  
Hiroyuki Oyanagi
Keyword(s):  
Synchrotron Radiation ◽  
Materials Science ◽  
X Rays ◽  
X Ray ◽  
Curved Trajectories ◽  
Wide Range ◽  
Materials Research ◽  
Novel Processing ◽  
Characterization Of Materials

X-rays have found a wide range of applications in chemistry, physics, and materials engineering since their discovery in 1895 by W. Roentgen. The materials science community uses x-ray-based techniques extensively for characterization of materials. In the 1970s a new tunable source of x-rays from the radiation produced by synchrotron accelerators emerged. Synchrotron radiation (SR) is an intense and forward-focused beam of radiation that is emitted when the path of an electron traveling at almost the speed of light is bent by a magnetic field. Figure 1 illustrates the evolution of radiation intensity provided by various x-ray sources. In situ SR techniques provide real-time observation of atomic arrangements with high spatial sensitivity and precision, which are important features not only in fundamental materials research, but also in the development of novel processing techniques and in the search for new exotic materials. A major advantage of SR is that it covers a wide range of wavelengths continuously from infrared to gamma rays. This feature is attractive since a wealth of detailed information on the electronic and structural properties of materials can be obtained by optimizing the wavelength of the radiation.Since the establishment of “first generation” facilities in the early 1970s, the x-ray emittance from synchrotron storage rings, where electrons traveling at almost relativistic speed s are constrained by magnetic fields to follow curved trajectories, has shown dramatic improvements. See Table I for an extensive list of SR facilities presentiy in use throughout the world.

Growth, Structure, and Mechanical Properties of Pulsed Laser Deposited TiN/TiB2 Microlaminates

1996 ◽  
Vol 436 ◽  
Author(s):  
Ashok Kumar ◽  
R. B. Inturi ◽  
U. Ekanayake ◽  
H. L. Chan ◽  
J. A. Barnard
Keyword(s):  
Mechanical Properties ◽  
Protective Coatings ◽  
Pulsed Laser ◽  
Single Layer ◽  
High Hardness ◽  
Hard Coatings ◽  
High Melting Point ◽  
Wide Range ◽  
Hardness Values

AbstractHard coatings of TiN and TiB2 have many interesting properties such as high thermal and electrical conductivity, high melting point, good thermodynamic stability and combination of these properties make them an interesting prospect for a wide range of tribological and electronic applications. It is understood that artificial multilayer structures have shown anamolously high hardness and modulii making them likely candidate for future protective coatings. Single layer of TiN, TiB2, and TiB2/TiN microlaminates coatings with varying thickness have been deposited on Si (100) and oxidized Si(111) substrates by in-situ pulsed laser deposition method. These films are deposited at 10 Hz repetition rate of excimer laser (λ = 248 nm). Our preliminary results show that elastic modulii and hardness values of multilayered coatings are superior than monolithic coatings of either of the two constituent materials. The coatings have been characterized by X-ray diffiractometer and AFM techniques. Detailed results have been presented to correlate the effect of microlaminate thickness on the mechanical properties.

scholarly journals Highly accurate dating of micrometre-scale baddeleyite domains through combined focused ion beam extraction and U-Pb thermal ionisation mass spectrometry (FIB-TIMS)

2019 ◽  
Author(s):  
Lee F. White ◽  
Kimberly T. Tait ◽  
Sandra L. Kamo ◽  
Desmond E. Moser ◽  
James R. Darling
Keyword(s):  
Mass Spectrometry ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Cutting Speed ◽  
Thermal Ionisation Mass Spectrometry ◽  
Ionisation Mass Spectrometry ◽  
Wide Range ◽  
Milled Surface ◽  
Ionisation Mass

Abstract. Baddeleyite is a powerful chronometer of mafic magmatic and meteorite impact processes. High precision and accuracy U-Pb ages can be measured from single grains by isotope dilution thermal ionisation mass spectrometry (ID-TIMS), but this requires destruction of the host rock for highly challenging grain isolation and dissolution. As a result, the technique is rarely applied to precious samples with very limited availability (such as lunar, Martian and asteroidal meteorites and returned samples) or samples containing small baddeleyite grains that cannot readily be isolated by conventional mineral separation techniques. Here, we use focused ion beam (FIB) techniques, utilising both Xe+ plasma and Ga+ ion sources, to liberate baddeleyite subdomains in-situ, allowing their extraction for ID-TIMS dating. We have analysed the U-Pb isotope systematics of domains ranging between 200 um and 10 um in length and 5 ug to 0.1 ug in mass. In total, seven domains of Phalaborwa baddeleyite extracted using a Xe+-pFIB yield a weighted mean 207 Pb/206 Pb age of 2060.1 ± 2.4 Ma (0.12 %; all uncertainties 2 sigma), within uncertainty of reference values. The smallest extracted domain (ca. 10 × 15 times; 10 um) yields an internal 207 Pb/206 Pb uncertainty of ±0.15 %. Comparable levels of precision are achieved using a Ga+-source FIB instrument (±0.20 %), though the slower cutting speed limits potential application to larger grains. While the U-Pb data are between 0.5 and 13.6 % discordant, the results generate a precise upper intercept age in U-Pb concordia space of 2061.1 × 7.4 Ma; (0.72 %). Importantly, the extent of discordance does not correlate with the ratio of material to ion-milled surface area, showing that the FIB extraction does not induce disturbance of U-Pb systematics even the smallest extracted domains. Instead, we confirm the natural U-Pb variation and discordance within the Phalaborwa baddeleyite population observed with other geochronological techniques. Our results demonstrate the FIB-TIMS technique to be a powerful tool for high-accuracy in-situ U-Pb dating, which makes a wide range of targets and processes newly accessible to geochronology.

scholarly journals Structure and nature of ice XIX

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christoph G. Salzmann ◽  
John S. Loveday ◽  
Alexander Rosu-Finsen ◽  
Craig L. Bull
Keyword(s):  
Phase Transition ◽  
Materials Science ◽  
Water Molecules ◽  
Orientational Disorder ◽  
Structural Distortions ◽  
Scientific Disciplines ◽  
Wide Range ◽  
Alternative Type ◽  
In Situ Neutron Diffraction

AbstractIce is a material of fundamental importance for a wide range of scientific disciplines including physics, chemistry, and biology, as well as space and materials science. A well-known feature of its phase diagram is that high-temperature phases of ice with orientational disorder of the hydrogen-bonded water molecules undergo phase transitions to their ordered counterparts upon cooling. Here, we present an example where this trend is broken. Instead, hydrochloric-acid-doped ice VI undergoes an alternative type of phase transition upon cooling at high pressure as the orientationally disordered ice remains disordered but undergoes structural distortions. As seen with in-situ neutron diffraction, the resulting phase of ice, ice XIX, forms through a Pbcn-type distortion which includes the tilting and squishing of hexameric clusters. This type of phase transition may provide an explanation for previously observed ferroelectric signatures in dielectric spectroscopy of ice VI and could be relevant for other icy materials.

scholarly journals Antibacterial Activity of Nanocomposites of Copper and Cellulose

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ricardo J. B. Pinto ◽  
Sara Daina ◽  
Patrizia Sadocco ◽  
Carlos Pascoal Neto ◽  
Tito Trindade
Keyword(s):  
Antibacterial Activity ◽  
Chemical Nature ◽  
Materials Science ◽  
Cellulose Fibers ◽  
Ex Situ ◽  
Antibacterial Materials ◽  
Paper Coatings ◽  
Wide Range ◽  
Potential Use

The design of cheap and safe antibacterial materials for widespread use has been a challenge in materials science. The use of copper nanostructures combined with abundant biopolymers such as cellulose offers a potential approach to achieve such materials though this has been less investigated as compared to other composites. Here, nanocomposites comprising copper nanofillers in cellulose matrices have been prepared byin situandex situmethods. Two cellulose matrices (vegetable and bacterial) were investigated together with morphological distinct copper particulates (nanoparticles and nanowires). A study on the antibacterial activity of these nanocomposites was carried out forStaphylococcus aureusandKlebsiella pneumoniae, as pathogen microorganisms. The results showed that the chemical nature and morphology of the nanofillers have great effect on the antibacterial activity, with an increase in the antibacterial activity with increasing copper content in the composites. The cellulosic matrices also show an effect on the antibacterial efficiency of the nanocomposites, with vegetal cellulose fibers acting as the most effective substrate. Regarding the results obtained, we anticipate the development of new approaches to prepare cellulose/copper based nanocomposites thereby producing a wide range of interesting antibacterial materials with potential use in diverse applications such as packaging or paper coatings.

The SESAME materials science beamline for XRD applications

2017 ◽  
Vol 32 (S1) ◽  
pp. S6-S12
Author(s):  
M. Abdellatief ◽  
L. Rebuffi ◽  
H. Khosroabadi ◽  
M. Najdawi ◽  
T. Abu-Hanieh ◽  
...  
Keyword(s):  
Materials Science ◽  
Beam Size ◽  
X Ray Diffraction ◽  
Standard Material ◽  
X Ray ◽  
Swiss Light Source ◽  
Wide Range ◽  
Under Construction ◽  
Effective Beam

We present a detailed description of the SESAME Materials Science (MS) beamline for X-ray diffraction (XRD) applications, presently under construction in Allan, Jordan. The beamline is based on components previously installed at the Swiss Light Source, but modifications in the beamline design have been introduced to match the characteristics of the SESAME storage ring. The SESAME MS beamline will accommodate XRD experiments in the energy range between 5 and 25 keV. The beamline ray tracing analysis at 10 keV estimates the flux at the sample to be of the order of 1013 (photons s−1), the energy resolution is about 2 eV and the effective beam size at the sample of 300 × 2800 µm2. Investigations of microstruture will be possible as the instrumental broadening, resulted from simulating the diffraction pattern for a standard material, is of the order of 0.01° at 15 keV. A wide range of applications will be possible at the beamline, such as powder diffraction studies, single crystals and in situ XRD. The commisioning of the beamline is expected to be in the second half of 2017.

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