scholarly journals Characterization of Open-Cell Sponges via Magnetic Resonance and X-ray Tomography

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2187
Author(s):  
Gabriele M. Cimmarusti ◽  
Abhishek Shastry ◽  
Matthieu N. Boone ◽  
Veerle Cnudde ◽  
Karl Braeckman ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Pore Size ◽  
Average Pore Size ◽  
Relaxation Times ◽  
Polyurethane Foams ◽  
T2 Relaxation ◽  
Open Cell ◽  
X Ray ◽  
Average Maximum ◽  
Maximum Opening

The applications of polymeric sponges are varied, ranging from cleaning and filtration to medical applications. The specific properties of polymeric foams, such as pore size and connectivity, are dependent on their constituent materials and production methods. Nuclear magnetic resonance imaging (MRI) and X-ray micro-computed tomography (µCT) offer complementary information about the structure and properties of porous media. In this study, we employed MRI, in combination with µCT, to characterize the structure of polymeric open-cell foam, and to determine how it changes upon compression, µCT was used to identify the morphology of the pores within sponge plugs, extracted from polyurethane open-cell sponges. MRI T2 relaxation maps and bulk T2 relaxation times measurements were performed for 7° dH water contained within the same polyurethane foams used for µCT. Magnetic resonance and µCT measurements were conducted on both uncompressed and 60% compressed sponge plugs. Compression was achieved using a graduated sample holder with plunger. A relationship between the average T2 relaxation time and maximum opening was observed, where smaller maximum openings were found to have a shorter T2 relaxation times. It was also found that upon compression, the average maximum opening of pores decreased. Average pore size ranges of 375–632 ± 1 µm, for uncompressed plugs, and 301–473 ± 1 µm, for compressed plugs, were observed. By determining maximum opening values and T2 relaxation times, it was observed that the pore structure varies between sponges within the same production batch, as well as even with a single sponge.

Textural and pore size analysis of carbonates from integrated core and nuclear magnetic resonance logging: An Arbuckle study

2015 ◽  
Vol 3 (1) ◽  
pp. SA77-SA89 ◽  
Author(s):  
John Doveton ◽  
Lynn Watney
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Pore Size ◽  
Relaxation Times ◽  
T2 Relaxation Time ◽  
T2 Relaxation ◽  
Nmr Logging ◽  
The Core ◽  
Nuclear Magnetic

The T2 relaxation times recorded by nuclear magnetic resonance (NMR) logging are measures of the ratio of the internal surface area to volume of the formation pore system. Although standard porosity logs are restricted to estimating the volume, the NMR log partitions the pore space as a spectrum of pore sizes. These logs have great potential to elucidate carbonate sequences, which can have single, double, or triple porosity systems and whose pores have a wide variety of sizes and shapes. Continuous coring and NMR logging was made of the Cambro-Ordovician Arbuckle saline aquifer in a proposed CO2 injection well in southern Kansas. The large data set gave a rare opportunity to compare the core textural descriptions to NMR T2 relaxation time signatures over an extensive interval. Geochemical logs provided useful elemental information to assess the potential role of paramagnetic components that affect surface relaxivity. Principal component analysis of the T2 relaxation time subdivided the spectrum into five distinctive pore-size classes. When the T2 distribution was allocated between grainstones, packstones, and mudstones, the interparticle porosity component of the spectrum takes a bimodal form that marks a distinction between grain-supported and mud-supported texture. This discrimination was also reflected by the computed gamma-ray log, which recorded contributions from potassium and thorium and therefore assessed clay content reflected by fast relaxation times. A megaporosity class was equated with T2 relaxation times summed from 1024 to 2048 ms bins, and the volumetric curve compared favorably with variation over a range of vug sizes observed in the core. The complementary link between grain textures and pore textures was fruitful in the development of geomodels that integrates geologic core observations with petrophysical log measurements.

Development and Characterization of SS316L Foam Prepared by Powder Metallurgy Route

2014 ◽  
Vol 534 ◽  
pp. 31-37 ◽  
Author(s):  
Fazimah Mat Noor ◽  
Khairur Rijal Jamaluddin ◽  
Sufizar Ahmad ◽  
Rosdi Ibrahim ◽  
Noor Idayu Mad Rosip
Keyword(s):  
Powder Metallurgy ◽  
Pore Size ◽  
Bone Cells ◽  
Cell Structure ◽  
Average Pore Size ◽  
Polyurethane Foams ◽  
Vacuum Furnace ◽  
Average Pore ◽  
Open Cell ◽  
Replication Method

Open cell foams, made on the basis of polyurethane foams replication method are well known and had been widely used since decades. The advantage of the network-like metal foams is it exhibits a natural bone-like structure which enables ingrowth of bone cells and blood vessels. The aim of the present study is to develop SS316L foam with an open cell structure by using powder metallurgy routes via foam replication method. The SS316L slurry was produced by mixing SS316L powder with Polyethylene Glycol (PEG), Methylcellulose (CMC) and distilled water. The composition of the SS316L powder in the slurry was varied from 40 to 60 wt. %. Then, polymeric foam template was impregnated in SS316L slurry and dried at room temperature. Sintering was carried out in a high temperature vacuum furnace at 1300°C. The microstructure of the SS316L foam produced was observed by Scanning Electron Microscope (SEM) and the elemental analysis was carried by Energy Dispersive X-ray (EDX). It was found that pore size are within 200-400μm and the average pore size is 293μ. The detected elements in the SS316L foam were C, Al, Ca, O, Cr, Fe, Mo, Ni and Si.

Quantification of T1, T2 relaxation times from Magnetic Resonance Fingerprinting radially undersampled data using analytical transformations

2021 ◽  
Vol 80 ◽  
pp. 81-89
Author(s):  
Nikolaos Dikaios ◽  
Nicholas E. Protonotarios ◽  
Athanasios S. Fokas ◽  
George A. Kastis
Keyword(s):  
Magnetic Resonance ◽  
Relaxation Times ◽  
T2 Relaxation ◽  
Undersampled Data

Evaluation of Relaxation Time Measurements by Magnetic Resonance Imaging

1987 ◽  
Vol 28 (3) ◽  
pp. 345-351 ◽  
Author(s):  
L. Kjær ◽  
C. Thomsen ◽  
O. Henriksen ◽  
P. Ring ◽  
M. Stubgaard ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Diffusion Processes ◽  
Relaxation Times ◽  
Gradient Field ◽  
Maximum Deviation ◽  
Resonance Imaging ◽  
T2 Relaxation ◽  
T1 And T2

Several circumstances may explain the great variation in reported proton T1 and T2 relaxation times usually seen. This study was designed to evaluate the accuracy of relaxation time measurements by magnetic resonance imaging (MRI) operating at 1.5 tesla. Using a phantom of nine boxes with different concentrations of CuSO4 and correlating the calculated T1 and T2 values with reference values obtained by two spectrometers (corrected to MRI-proton frequency=64 MHz) we found a maximum deviation of about 10 per cent. Measurements performed on a large water phantom in order to evaluate the homogeneity in the imaging plane showed a variation of less than 10 per cent within 10 cm from the centre of the magnet in all three imaging planes. Changing the gradient field strength apparently had no influence on the T2 values recorded. Consequently diffusion processes seem without significance. It is concluded that proton T1 and T2 relaxation times covering the majority of the biologic range can be measured by MRI with an overall accuracy of 5 to 10 per cent. Quality control studies along the lines indicated in this study are recommended.

Magnetic resonance relaxometry in monozygotic twins discordant and concordant for schizophrenia

2005 ◽  
Vol 20 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Filip Spaniel ◽  
Vit Herynek ◽  
Tomas Hajek ◽  
Monika Dezortova ◽  
Jiri Horacek ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Globus Pallidus ◽  
Relaxation Times ◽  
Monozygotic Twins ◽  
T2 Relaxation ◽  
T1 Relaxation ◽  
Significant Prolongation ◽  
Healthy Control ◽  
Genetic Loading ◽  
Mz Twins

AbstractT1 and T2 relaxation times were examined in four pairs of monozygotic (MZ) twins discordant and concordant for schizophrenia with low and high genetic loading for the illness and five healthy control MZ twin pairs. Patients with schizophrenia (n = 11) showed significant prolongation in T1 relaxation times in the globus pallidus (GP) bilaterally (P < 0.005, Bonferroni corrected) when compared to 14 healthy MZ twins.

Magnetic Resonance Microscopy of Chemically-Induced Liver Foci

1989 ◽  
Vol 17 (4_part_1) ◽  
pp. 613-616 ◽  
Author(s):  
G. Allan Johnson ◽  
Robert R. Maronpot
Keyword(s):  
Magnetic Resonance ◽  
Imaging Technique ◽  
Relaxation Times ◽  
Basic Research ◽  
Resonance Imaging ◽  
T2 Relaxation ◽  
Spin Lattice ◽  
Chemically Induced ◽  
Magnetic Resonance Imaging Mri

Magnetic resonance imaging (MRI) is a new imaging technique used in clinical diagnosis. This paper describes extension of the technique to basic research applications–specifically detecting and characterizing chemically-induced liver neoplasms and foci of cellular alteration. Two systems have been built that allow spatial microscopic resolution–more than 100,000 x greater than that of earlier efforts. Use of spin-lattice (T1) and spin-spin (T2) relaxation times permits detailed characterization of the tissue.

Magnetic resonance fingerprinting using echo-planar imaging: Joint quantification of T1 and T2∗ relaxation times

2016 ◽  
Vol 78 (5) ◽  
pp. 1724-1733 ◽  
Author(s):  
Benedikt Rieger ◽  
Fabian Zimmer ◽  
Jascha Zapp ◽  
Sebastian Weingärtner ◽  
Lothar R. Schad
Keyword(s):  
Magnetic Resonance ◽  
Relaxation Times ◽  
Echo Planar Imaging ◽  
Planar Imaging ◽  
T2 Relaxation ◽  
T1 And T2 ◽  
Echo Planar

On the investigation of homeopathic potencies using low resolution NMR T2 relaxation times: an experimental and critical survey of the work of Roland Conte et al

2001 ◽  
Vol 90 (01) ◽  
pp. 5-13 ◽  
Author(s):  
LR Milgrom ◽  
KR King ◽  
J Lee ◽  
AS Pinkus
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nitric Acid ◽  
Magnetic Resonance ◽  
Spin Relaxation ◽  
Relaxation Times ◽  
Critical Survey ◽  
Low Resolution ◽  
T2 Relaxation ◽  
Experimental Artifact ◽  
Experimental Protocols

AbstractWe have attempted to reproduce differences in low resolution nuclear magnetic resonance (NMR) T2 spin–spin relaxation times between homeopathically potentised and unpotentised Nitric acid (nit-ac) solutions previously reported by Conte, et al. Using similar instrumentation and experimental protocols, we have shown that it is likely that Conte's original results are attributable to experimental artifact originating in the glassware used for the manufacture of the NMR tubes.

scholarly journals Особенности исследования состояния текущей среды методом ядерного магнитного резонанса

2020 ◽  
Vol 46 (2) ◽  
pp. 8
Author(s):  
В.В. Давыдов ◽  
Н.С. Мязин ◽  
В.И. Дудкин ◽  
Р.В. Давыдов
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Signal To Noise Ratio ◽  
Relaxation Times ◽  
The State ◽  
T2 Relaxation ◽  
Signal To Noise ◽  
Flowing Liquid ◽  
Registration System ◽  
Nuclear Magnetic

The features of the state investigation of a flowing liquid by nuclear magnetic resonance was defined. The methodology for the state investigation of the flowing medium by changing the values of the longitudinal T1 and transverse T2 relaxation times is justified. For the parameters of the registration system of the signal of nuclear magnetic resonance and magnetic fields are established relations between them. The implementation of these ratios allows to obtain a signal to noise ratio of more than 5 for carrying out measurements of T1 and T2 values in real time with an error not exceeding 1%. The results of experimental research are presented.

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