scholarly journals Inverse Method and Algorithm to Retrieve the Heat Diffusivity of Solid Samples in a Non-Destructive Way

2018 ◽  
Author(s):  
Ziemowit Ostrowski ◽  
Arkadiusz Ryfa ◽  
Zbigniew Buliński ◽  
Wojciech P. Adamczyk
Keyword(s):  
Inverse Method ◽  
Solid Samples ◽  
Heat Diffusivity ◽  
Non Destructive

scholarly journals New Inverse Method for Determining Uniaxial Flow Properties by Spherical Indentation Test

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Guoyao Chen ◽  
Xiaocheng Zhang ◽  
Jiru Zhong ◽  
Jin Shi ◽  
Qiongqi Wang ◽  
...  
Keyword(s):  
Tensile Properties ◽  
Inverse Method ◽  
Engineering Application ◽  
Indentation Test ◽  
New Method ◽  
Spherical Indentation ◽  
Flow Properties ◽  
Indentation Force ◽  
Non Destructive ◽  
Depth Curves

AbstractThe spherical indentation test has been successfully applied to inversely derive the tensile properties of small regions in a non-destructive way. Current inverse methods mainly rely on extensive iterative calculations, which yield a considerable computational costs. In this paper, a database method is proposed to determine tensile flow properties from a single indentation force-depth curves to avoid iterative simulations. Firstly, a database that contain numerous indentation force-depth curves is established by inputting varied Ludwic material parameters into the indentation finite elements model. Secondly, for a given experimental indentation curve, a mean square error (MSE) is designated to evaluate the deviation between the experimental curve and each curve in the database. Finally, the true stresses at a series of plastic strain can be acquired by analyzing these deviations. To validate this new method, three different steels, i.e. A508, 2.25Cr1Mo and 316L are selected. Both simulated indentation curves and experimental indentation curves are used as inputs of the database to inversely acquire the flow properties. The result indicates that the proposed approach provides impressive accuracy when simulated indentation curves are used, but is less accurate when experimental curves are used. This new method can derive tensile properties in a much higher efficiency compared with traditional inverse method and are therefore more adaptive to engineering application.

Experimental Study of Internal Heat Transfer Coefficients in a Rectangular, Ribbed Channel Using a Non-Invasive, Non-Destructive, Transient Inverse Method

2008 ◽  
Author(s):  
Peter Heidrich ◽  
Jens von Wolfersdorf ◽  
Martin Schnieder
Keyword(s):  
Heat Transfer ◽  
Measurement Method ◽  
Inverse Method ◽  
Turbine Blades ◽  
Internal Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Non Invasive ◽  
Non Destructive ◽  
Internal Heat Transfer

This paper describes a non-invasive, non-destructive inverse measurement method that allows one to determine heat transfer coefficients in internal passages of real turbine blades experimentally. For this purpose, a test rig with a fast responding heater was designed to fulfill the requirement of a sudden increase in the air temperature within the internal cooling passages. The outer surface temperatures of the specimen were measured using an infrared camera. To suggest the spatial distribution of the internal heat transfer coefficients from the transient characteristics of the outside surface temperature the inverse heat transfer problem was solved. Differing from former studies which made a thin wall assumption, the conduction inside a finite wall was modelled. Based on a one-dimensional forward solution the best fitting optimization method, the Levenberg-Marquardt algorithm, was chosen. This was verified with artificial data including random noise with positive results. Experimental data were measured for a rectangular H/W = 1:4 aspect ratio channel made of stainless steel with parallel 90° and 45° ribs at Reynolds numbers from 25,000 to 80,000. Results of 90° ribs were compared with simultaneously acquired data using the transient liquid crystal technique. Furthermore the influence of Reynolds number on pitch averaged heat transfer results were evaluated for both rib configurations. These results based on infrared data were compared with earlier studies. It is concluded that the presented experimental measurement method using the transient inverse method could be used to quantitatively determine heat transfer coefficients in internal passages of real turbine blades.

scholarly journals Efficient Extraction from Mice Feces for NMR Metabolomics Measurements with Special Emphasis on SCFAs

Metabolites ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 55
Author(s):  
Adrian Hauser ◽  
Philipp Eisenmann ◽  
Claudia Muhle-Goll ◽  
Burkhard Luy ◽  
Andreas Dötsch ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Initial Step ◽  
Short Chain Fatty Acids ◽  
Sample Type ◽  
Reference Substance ◽  
High Fat ◽  
Solid Samples ◽  
Nmr Metabolomics ◽  
Efficient Extraction ◽  
Non Destructive

Nuclear magnetic resonance (NMR) spectroscopy is one of the most promising methods for use in metabolomics studies as it is able to perform non targeted measurement of metabolites in a quantitative and non-destructive way. Sample preparation of liquid samples like urine or blood serum is comparatively easy in NMR metabolomics, because mainly buffer and chemical shift reference substance are added. For solid samples like feces suitable extraction protocols need to be defined as initial step, where the exact protocol depends on sample type and features. Focusing on short chain fatty acids (SCFAs) in mice feces, we describe here a set of extraction protocols developed with the aim to suppress changes in metabolite composition within 24 h after extraction. Feces are obtained from mice fed on either standard rodent diet or high fat diet. The protocols presented in this manuscript are straightforward for application, and successfully minimize residual bacterial and enzymatic activities. Additionally, they are able to minimize the lipid background originating from the high fat diet.

Luminescence from individual dislocations in II-VI and III-V semiconductors

1991 ◽  
Vol 49 ◽  
pp. 834-835
Author(s):  
J W Steeds
Keyword(s):  
Group Iv ◽  
Luminescence Properties ◽  
Carrier Recombination ◽  
Transmission Electron ◽  
Wide Range ◽  
Basic Physics ◽  
Semiconducting Compounds ◽  
Diamond Group ◽  
Non Destructive ◽  
Technological Significance

There is a wide range of experimental results related to dislocations in diamond, group IV, II-VI, III-V semiconducting compounds, but few of these come from isolated, well-characterized individual dislocations. We are here concerned with only those results obtained in a transmission electron microscope so that the dislocations responsible were individually imaged. The luminescence properties of the dislocations were studied by cathodoluminescence performed at low temperatures (~30K) achieved by liquid helium cooling. Both spectra and monochromatic cathodoluminescence images have been obtained, in some cases as a function of temperature.There are two aspects of this work. One is mainly of technological significance. By understanding the luminescence properties of dislocations in epitaxial structures, future non-destructive evaluation will be enhanced. The second aim is to arrive at a good detailed understanding of the basic physics associated with carrier recombination near dislocations as revealed by local luminescence properties.

Forensic Identifications Aided by Scanning Electron Microscopy of Silicone-Epoxy Microreplicas of Calcified and Cornified Structures

1975 ◽  
Vol 33 ◽  
pp. 678-679 ◽  
Author(s):  
R.F. Sognnaes
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Forensic Science ◽  
George Washington ◽  
Epithelial Surface ◽  
Extended Application ◽  
Tissue Surfaces ◽  
Non Destructive ◽  
Scanning Electron ◽  
Surface Changes

Sufficient experience has been gained during the past five years to suggest an extended application of microreplication and scanning electron microscopy to problems of forensic science. The author's research was originally initiated with a view to develop a non-destructive method for identification of materials that went into objects of art, notably ivory and ivories. This was followed by a very specific application to the identification and duplication of the kinds of materials from animal teeth and tusks which two centuries ago went into the fabrication of the ivory dentures of George Washington. Subsequently it became apparent that a similar method of microreplication and SEM examination offered promise for a whole series of problems pertinent to art, technology and science. Furthermore, what began primarily as an application to solid substances has turned out to be similarly applicable to soft tissue surfaces such as mucous membranes and skin, even in cases of acute, chronic and precancerous epithelial surface changes, and to post-mortem identification of specific structures pertinent to forensic science.

A general inverse method for modelling extensional sedimentary basins

2000 ◽  
Vol 12 (3-4) ◽  
pp. 219-226 ◽  
Author(s):  
P. Bellingham ◽  
N. White
Keyword(s):  
Inverse Method ◽  
Sedimentary Basins
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