Calibrated sub-micron temperature mapping of an operating plasmonic HAMR device by thermoreflectance imaging

MRS Advances ◽  
2017 ◽  
Vol 2 (58-59) ◽  
pp. 3613-3618
Author(s):  
Gregory T. Hohensee ◽  
Dustin Kendig ◽  
Ella Pek ◽  
Wan Kuang ◽  
Kazuaki Yazawa ◽  
...  
Keyword(s):  
High Performance ◽  
Numerical Models ◽  
Near Field ◽  
Numerical Aperture ◽  
Thermal Characterization ◽  
Absolute Temperature ◽  
Optical Diffraction ◽  
Time Resolved ◽  
Nanoscale Structures ◽  
Transient Calibration

ABSTRACTThermal characterization of nano-featured devices is a critical challenge for the development of high performance devices. Although far-field thermoreflectance imaging is limited in spatial resolution by the optical diffraction limit, it is more amenable to absolute temperature calibration of plasmonic devices than existing near-field scanning probe tip methods. We have built an advanced thermoreflectance microscope capable of 50 ns time-resolved, diffraction-limited temperature imaging that can account and correct for thermal expansion, sample drift, numerical aperture, and polarization induced variations in the apparent thermoreflectance coefficient of nanoscale structures. We developed a per-pixel transient calibration technique using this microscope to measure the absolute temperature of an operating heat-assisted magnetic recording (HAMR) head, including features as narrow as 200 nm. The resulting temperature information can be used to experimentally validate numerical models in the design process of such plasmonic devices.

Experimental and Numerical Evaluation of UHPFRC Slabs Subjected to Contact and Close-In Explosion

2020 ◽  
Vol 309 ◽  
pp. 180-185
Author(s):  
Ondřej Janota ◽  
Marek Foglar
Keyword(s):  
Numerical Simulation ◽  
Reinforced Concrete ◽  
Numerical Model ◽  
High Performance ◽  
Numerical Evaluation ◽  
Numerical Models ◽  
Blast Resistance ◽  
Near Field ◽  
Fibre Reinforced Concrete ◽  
High Performance Fibre

This paper presents achievements in the field of the numerical simulation of the fibrere reinforced concrete (FRC) and ultra-high performance fibre reinforced concrete (UHPFRC). The numerical simulations were performed to verify results of two experimental programmes focused on the blast resistance of FRC and UHPFRC. The response of the FRC and UHPFRC slabs to the contact and near-field blast was studied in these two experiments. As the detail behaviour of specimens could not be observed because of the blast load, the numerical models were prepared. The accuracy of the numerical models was evaluated based on the comparison of numerical and experimental results. Different approaches for blast simulation were tested and compared. The results indicate that the various phenomena (e.g. overpressure propagation, stress cumulation, crack propagation and damage extend) can be successfully simulated. However, the comparison of the soffit velocity, measured with the PDV unit and numerical model showed shortcomings of the numerical model. These numerical model inaccuracies are discussed and their reasons presented.

Numerical Inversion of Laplace Transform for Time Resolved Thermal Characterization Experiment

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
J. Toutain ◽  
J.-L. Battaglia ◽  
C. Pradere ◽  
J. Pailhes ◽  
A. Kusiak ◽  
...  
Keyword(s):  
Fourier Series ◽  
Laplace Transform ◽  
Periodic Function ◽  
Thermal Characterization ◽  
Inverse Laplace Transform ◽  
Numerical Inversion ◽  
Time Resolved ◽  
Reliable Technique ◽  
Numerical Inverse Laplace Transform ◽  
Thermal Disturbance

The aim of this technical brief is to test numerical inverse Laplace transform methods with application in the framework of the thermal characterization experiment. The objective is to find the most reliable technique in the case of a time resolved experiment based on a thermal disturbance in the form of a periodic function or a distribution. The reliability of methods based on the Fourier series methods is demonstrated.

Design and evaluation of a wedge-type anchor for fibre reinforced polymer tendons

2000 ◽  
Vol 27 (5) ◽  
pp. 985-992 ◽  
Author(s):  
T I Campbell ◽  
N G Shrive ◽  
K A Soudki ◽  
A Al-Mayah ◽  
J P Keatley ◽  
...  
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Numerical Models ◽  
Ultra High Performance Concrete ◽  
Reinforced Polymer ◽  
Anchorage System ◽  
Fibre Reinforced Polymer ◽  
Load Tests ◽  
Tendon Tension ◽  
Post Tensioning

The development of a wedge-type anchorage system for fibre reinforced polymer (FRP) tendons, as part of an overall corrosion-free post-tensioning system, is outlined in this paper. A stainless steel anchor is described, and results from numerical models and load tests to evaluate its behaviour under loads from anchor set, as well as static and repeated tendon tension, are presented. An alternative wedge-type anchorage system made from ultra-high performance concrete is also described. It is shown that, although significant progress has been made in development of the anchorage, further work is required to make it more robust.Key words: FRP tendons, post-tensioning, anchorage, corrosion-free, mathematical models, load tests, concrete.

Time-Resolved Micro Liquid Desorption Mass Spectrometry: Mechanism, Features, and Kinetic Applications

2006 ◽  
Vol 59 (2) ◽  
pp. 81 ◽  
Author(s):  
Ales Charvat ◽  
Andreas Bógehold ◽  
Bernd Abel
Keyword(s):  
Mass Spectrometry ◽  
Liquid Phase ◽  
High Speed ◽  
High Performance ◽  
Kinetic Studies ◽  
Solution Concentration ◽  
Bulk Water ◽  
Laser Wavelength ◽  
Time Resolved ◽  
Desorption Mass Spectrometry

Liquid water beam desorption mass spectrometry is an intriguing technique to isolate charged molecular aggregates directly from the liquid phase and to analyze them employing sensitive mass spectrometry. The liquid phase in this approach consists of a 10 µm diameter free liquid filament in vacuum which is irradiated by a focussed infrared laser pulse resonant with the OH-stretch vibration of bulk water. Depending upon the laser wavelength, charged (e.g. protonated) macromolecules are isolated from solution through a still poorly characterized mechanism. After the gentle liquid-to-vacuum transfer the low-charge-state aggregates are analyzed using time-of-flight mass spectrometry. A recent variant of the technique uses high performance liquid chromatography valves for local liquid injections of samples in the liquid carrier beam, which enables very low sample consumption and high speed sample analysis. In this review we summarize recent work to characterize the ‘desorption’ or ion isolation mechanism in this type of experiment. A decisive and interesting feature of micro liquid beam desorption mass spectrometry is that — under certain conditions — the gas-phase mass signal for a large number of small as well as supramolecular systems displays a surprisingly linear response on the solution concentration over many orders of magnitude, even for mixtures and complex body fluids. This feature and the all-liquid state nature of the technique makes this technique a solution-type spectroscopy that enables real kinetic studies involving (bio)polymers in solution without the need for internal standards. Two applications of the technique monitoring enzyme digestion of proteins and protein aggregation of an amyloid model system are highlighted, both displaying its potential for monitoring biokinetics in solution.

scholarly journals Modeling of Spray Combustion with a Steady Laminar Flamelet Model in an Aeroengine Combustion Chamber Based on OpenFOAM

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Yinli Xiao ◽  
Zupeng Wang ◽  
Zhengxin Lai ◽  
Wenyan Song
Keyword(s):  
Combustion Chamber ◽  
High Performance ◽  
Numerical Models ◽  
Spray Combustion ◽  
Combustion Chambers ◽  
Flamelet Model ◽  
Steady Laminar ◽  
Good Agreement ◽  
Laminar Flamelet ◽  
Laminar Flamelet Model

The development of high-performance aeroengine combustion chambers strongly depends on the accuracy and reliability of efficient numerical models. In the present work, a reacting solver with a steady laminar flamelet model and spray model has been developed in OpenFOAM and the solver details are presented. The solver is firstly validated by Sandia/ETH-Zurich flames. Furthermore, it is used to simulate nonpremixed kerosene/air spray combustion in an aeroengine combustion chamber with the RANS method. A comparison with available experimental data shows good agreement and validates the capability of the new developed solver in OpenFOAM.

Well-Aligned Graphene Oxide Nanosheets Decorated with Zinc Oxide Nanocrystals for High Performance Photocatalytic Application

2015 ◽  
Vol 14 (03) ◽  
pp. 1550007 ◽  
Author(s):  
K. Kaviyarasu ◽  
C. Maria Magdalane ◽  
E. Manikandan ◽  
M. Jayachandran ◽  
R. Ladchumananandasivam ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Graphene Oxide ◽  
High Performance ◽  
Chemical Reduction ◽  
Visible Region ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Graphene Oxides ◽  
X Ray ◽  
Nanoscale Structures

Graphene oxide (GO) nanosheets modified with zinc oxide nanocrystals were achieved by a green wet-chemical approach. As-obtained products were characterized by XRD, Raman spectra, XPS, HR-TEM, EDS, PL and Photocatalytic studies. XRD studies indicate that the GO nanosheet have the same crystal structure found in hexagonal form of ZnO . The enhanced Raman spectrum of 2D bands confirmed formation of single layer graphene oxides. The gradual photocatalytic reduction of the GO nanosheet in the GO : ZnO suspension of ethanol was studied by using X-ray photoelectron (XPS) spectroscopy. The nanoscale structures were observed and confirmed using high resolution transmission electron microscopy (HR-TEM). The evolution of the elemental composition, especially the various numbers of layers were determined from energy dispersive X-ray spectra (EDS). PL properties of GO : ZnO nanosheet were found to be dependent on the growth condition and the resultant morphology revealed that GO nanosheet were highly transparent in the visible region. The photocatalytic performance of GO : ZnO nanocomposites was performed under UV irradiation. Therefore, the ZnO nanocrystals in the GO : ZnO composite could be applied in gradual chemical reduction and consequently tuning the electrical conductivity of the graphene oxide nanosheet.

Ensemble-based data assimilation of volcanic aerosols using FALL3D+PDAF

2021 ◽  
Author(s):  
Leonardo Mingari ◽  
Andrew Prata ◽  
Federica Pardini
Keyword(s):  
Data Assimilation ◽  
Information Transfer ◽  
High Performance ◽  
Volcanic Ash ◽  
Numerical Models ◽  
Volcanic Eruptions ◽  
Column Height ◽  
Eruption Column ◽  
Operational Environment ◽  
Assimilation System

<p>Modelling atmospheric dispersion and deposition of volcanic ash is becoming increasingly valuable for understanding the potential impacts of explosive volcanic eruptions on infrastructures, air quality and aviation. The generation of high-resolution forecasts depends on the accuracy and reliability of the input data for models. Uncertainties in key parameters such as eruption column height injection, physical properties of particles or meteorological fields, represent a major source of error in forecasting airborne volcanic ash. The availability of nearly real time geostationary satellite observations with high spatial and temporal resolutions provides the opportunity to improve forecasts in an operational context. Data assimilation (DA) is one of the most effective ways to reduce the error associated with the forecasts through the incorporation of available observations into numerical models. Here we present a new implementation of an ensemble-based data assimilation system based on the coupling between the FALL3D dispersal model and the Parallel Data Assimilation Framework (PDAF). The implementation is based on the last version release of FALL3D (versions 8.x) tailored to the extreme-scale computing requirements, which has been redesigned and rewritten from scratch in the framework of the EU Center of Excellence for Exascale in Solid Earth (ChEESE). The proposed methodology can be efficiently implemented in an operational environment by exploiting high-performance computing (HPC) resources. The FALL3D+PDAF system can be run in parallel and supports online-coupled DA, which allows an efficient information transfer through parallel communication. Satellite-retrieved data from recent volcanic eruptions were considered as input observations for the assimilation system.</p>

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