In Situ Optical Analysis of Structural Changes in Polylactic Acid (PLA) during the Gas Dissolution Process

2014 ◽  
Vol 353 ◽  
pp. 131-136
Author(s):  
B. Notario ◽  
Javier Pinto ◽  
E. Solórzano ◽  
J. Escudero ◽  
J. Martín de León ◽  
...  
Keyword(s):  
Polylactic Acid ◽  
Structural Changes ◽  
Crystallization Process ◽  
Optical Measurements ◽  
Optical Parameters ◽  
Whole Process ◽  
Complex Phenomena ◽  
Non Destructive

An own-designed pressure vessel with glass windows has been employed to perform an in-situ characterization of the temporal evolution of the crystallization process of an amorphous polylactic acid (PLA) under different controlled CO2 pressures and temperatures. It has been proven that crystallinity can be related to optical parameters such as transmissivity, obtaining information about the whole process by optical measurements. The method has the advantage of measuring in-situ over bulk samples with a non-destructive tool. The obtained results have shown some unexpected trends that have been explained taking into account the complex phenomena occurring during the crystallization process of PLA in the presence of CO2 at high pressure.

Preparation and characterization of polylactic acid-g-bamboo fiber based on in-situ solid phase polymerization

2018 ◽  
Vol 123 ◽  
pp. 646-653 ◽  
Author(s):  
Yingfeng Zuo ◽  
Wenhao Li ◽  
Ping Li ◽  
Wenjie Liu ◽  
Xingong Li ◽  
...  
Keyword(s):  
Polylactic Acid ◽  
Solid Phase ◽  
Bamboo Fiber

scholarly journals An instrumented sample holder for time-lapse microtomography measurements of snow under advective airflow

2014 ◽  
Vol 3 (2) ◽  
pp. 179-185 ◽  
Author(s):  
P. P. Ebner ◽  
S. A. Grimm ◽  
M. Schneebeli ◽  
A. Steinfeld
Keyword(s):  
Structural Changes ◽  
Time Lapse ◽  
Temperature Gradients ◽  
Sample Holder ◽  
Experimental Characterization ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations ◽  
Snow Samples

Abstract. An instrumented sample holder was developed for time-lapse microtomography of snow samples to enable in situ nondestructive spatial and temporal measurements under controlled advective airflows, temperature gradients, and air humidities. The design was aided by computational fluid dynamics simulations to evaluate the airflow uniformity across the snow sample. Morphological and mass transport properties were evaluated during a 4-day test run. This instrument allows the experimental characterization of metamorphism of snow undergoing structural changes with time.

scholarly journals Worth a Closer Look: Raman Spectra of Lead-Pipe Scale

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1047
Author(s):  
Jill Dill Pasteris ◽  
Yeunook Bae ◽  
Daniel E. Giammar ◽  
Sydney N. Dybing ◽  
Claude H. Yoder ◽  
...  
Keyword(s):  
Cross Sections ◽  
Water System ◽  
Analytical Techniques ◽  
Real Time Analysis ◽  
Fiber Optic Probes ◽  
Lead Pipe ◽  
Lead Pipes ◽  
Non Destructive

The identification and characterization of lead-bearing and associated minerals in scales on lead pipes are essential to understanding and predicting the mobilization of lead into drinking water. Despite its long-recognized usefulness in the unambiguous identification of crystalline and amorphous solids, distinguishing between polymorphic phases, and rapid and non-destructive analysis on the micrometer spatial scale, the Raman spectroscopy (RS) technique has been applied only occasionally in the analysis of scales in lead service lines (LSLs). This article illustrates multiple applications of RS not just for the identification of phases, but also compositional and structural characterization of scale materials in harvested lead pipes and experimental pipe-loop/recirculation systems. RS is shown to be a sensitive monitor of these characteristics through analyses on cross-sections of lead pipes, raw interior pipe walls, particulates captured in filters, and scrapings from pipes. RS proves to be especially sensitive to the state of crystallinity of scale phases (important to their solubility) and to the specific chemistry of phases precipitated upon the introduction of orthophosphate to the water system. It can be used effectively alone as well as in conjunction with more standard analytical techniques. By means of fiber-optic probes, RS has potential for in situ, real-time analysis within water-filled pipes.

Non Destructive Characterization of Concrete Joints Using the Scaling Subtraction Method

2009 ◽  
Vol 417-418 ◽  
pp. 41-44
Author(s):  
Paola Antonaci ◽  
Pietro G. Bocca ◽  
Caterina L.E. Bruno ◽  
Antonio S. Gliozzi ◽  
Marco Scalerandi
Keyword(s):  
Structural Changes ◽  
Crack Opening ◽  
Subtraction Method ◽  
Damage Initiation ◽  
External Pressures ◽  
Concrete Joints ◽  
Non Destructive ◽  
Non Destructive Characterization ◽  
Potential Conditions

The evolution of concrete behavior in the proximity of a joint under the effect of varying external pressures is studied by means of a novel nonlinear ultrasonic technique denoted as Scaling Subtraction Method. The results obtained show that the proposed method is effective in describing the occurrence of micro-structural changes near the joint and detect potential conditions for crack opening and damage initiation.

Flamanville EPR RPV’s Heads Carbon Segregation: Characterization of the Segregation in the Heads

2018 ◽  
Author(s):  
Philippe Fichot ◽  
Olivier Calonne ◽  
Mathieu Segond ◽  
Stéphane Marie ◽  
Yvon Desnoyers ◽  
...  
Keyword(s):  
Carbon Content ◽  
Residual Carbon ◽  
Testing Program ◽  
Specific Strategy ◽  
Carbon Segregation ◽  
Geostatistical Approach ◽  
Short Time ◽  
Non Destructive

To characterize the mechanical properties of the residual carbon segregation of the Flamanville EPR RPV heads, a testing program has been defined by Framatome using three sacrificial representative heads. The first step of this program was a 3D characterization of the carbon content inside each piece. A specific strategy has been defined using two methods for the carbon measuring: - In situ measurements using a mobile arc spark spectrometer. This device allows a higher number of non-destructive measurements in a particularly constrained environment and in a short time, - Conventional spectrometry performed on chips sampled from the pieces. This technique is more accurate but is destructive and more time consuming. Also, to consolidate the representativeness of the sacrificial vessels heads, the results were analysed using a geostatistical approach. This paper presents how these two techniques have been used to characterize the carbon content in the segregated part of the pieces and the conclusion of the geostatistical analyses.

Characterization of Structure and Mechanical Properties of MoSi2-SiC Nanolayer Composites

1993 ◽  
Vol 322 ◽  
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell
Keyword(s):  
Mechanical Properties ◽  
Structural Changes ◽  
Crystallization Process ◽  
Mechanical Response ◽  
Cross Sectional ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Layer Structures ◽  
Amorphous Structures

AbstractA systematic study of the structure-mechanical properties relationship is reported for MoSi2-SiC nanolayer composites. Alternating layers of MoSi2 and SiC were synthesized by DCmagnetron and if-diode sputtering, respectively. Cross-sectional transmission electron microscopy was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures. Nanoindentation was employed to characterize the mechanical response as a function of the structural changes. As-sputtered material exhibits amorphous structures in both types of layers and has a hardness of 11GPa and a modulus of 217GPa. Subsequent heat treatment induces crystallization of MoSi2 to form the C40 structure at 500°C and SiC to form the a structure at 700°C. The crystallization process is directly responsible for the hardness and modulus increase in the multilayers. A hardness of 24GPa and a modulus of 340GPa can be achieved through crystallizing both MoSi2 and SiC layers. Annealing at 900°C for 2h causes the transformation of MoSi2 into the Cllb structure, as well as spheroidization of the layering to form a nanocrystalline equiaxed microstructure. A slight degradation in hardness but not in modulus is observed accompanying the layer break-down.

scholarly journals An in situ Raman spectroscopy-based microfluidic “lab-on-a-chip” platform for non-destructive and continuous characterization of Pseudomonas aeruginosa biofilms

2015 ◽  
Vol 51 (43) ◽  
pp. 8966-8969 ◽  
Author(s):  
Jinsong Feng ◽  
César de la Fuente-Núñez ◽  
Michael J. Trimble ◽  
Jie Xu ◽  
Robert E. W. Hancock ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Raman Spectroscopy ◽  
Lab On A Chip ◽  
Confocal Raman Microscopy ◽  
In Situ Raman Spectroscopy ◽  
In Situ Raman ◽  
Confocal Raman ◽  
Non Destructive

Pseudomonas aeruginosabiofilm was cultivated and characterized in a microfluidic “lab-on-a-chip” platform coupled with confocal Raman microscopy in a non-destructive manner.

Quantitative Analysis of Raman Spectra from Diamond Like Carbon: Calibration Transfer

1998 ◽  
Vol 555 ◽  
Author(s):  
S. S. Rosenblum ◽  
Kevin L. Davis ◽  
James M. Tedesco
Keyword(s):  
Raman Spectroscopy ◽  
Hard Disk Drives ◽  
Diamond Like Carbon ◽  
Disk Drives ◽  
Calibration Transfer ◽  
Carbon Coatings ◽  
Protective Layers ◽  
Non Destructive

AbstractWe report on Raman studies of diamond-like carbon (DLC) films; in particular, we report on the instrumentation and methodology required for comparing Raman measurements taken on different Raman analyzers. Raman spectroscopy has taken on an increasingly important role in materials processing because of its capability of performing non-destructive, in situ characterization of thin films. In particular, noncrystalline carbon coatings have become ubiquitous as protective layers on everything from machine tools to hard disk drives. As tolerances on coating properties begin to play an important part in determining device failure, Raman spectroscopy has found ever greater application as a quality control/quality assurance tool. However, use of Raman as an analytical tool has been hampered by the inability to quantitatively compare spectra obtained with different Raman analyzers. By using automated, robust calibration protocols on both the wavelength and intensity axes, we have demonstrated cross-instrument calibration transfer of DLC films.

In situ characterization of structural changes and the fraction of aligned carbon nanotube networks produced by stretching

Carbon ◽  
2012 ◽  
Vol 50 (10) ◽  
pp. 3859-3867 ◽  
Author(s):  
Shu Li ◽  
Jin Gyu Park ◽  
Zhiyong Liang ◽  
Theo Siegrist ◽  
Tao Liu ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Structural Changes ◽  
In Situ Characterization ◽  
Carbon Nanotube Networks

In-Situ X-Ray Characterization of LiMn2O4: A Comparison of Structural and Electrochemical Behavior

1997 ◽  
Vol 496 ◽  
Author(s):  
Mark A. Rodriguez ◽  
David Ingersoll ◽  
Daniel H. Doughty
Keyword(s):  
Crystal Structure ◽  
Structural Changes ◽  
Phase Changes ◽  
X Ray ◽  
In Situ Xrd ◽  
Electrochemical Cycling ◽  
Kinetic Effects ◽  
Carbon Anodes

ABSTRACTLixMn2O4 materials are of considerable interest in battery research and development. The crystal structure of this material can significantly affect the electrochemical performance. The ability to monitor the changes of the crystal structure during use, that is during electrochemical cycling, would prove useful to verify these types of structural changes. We report in-situ XRD measurements of LiMn2O4 cathodes with the use of an electrochemical cell designed for in-situ X-ray analysis. Cells prepared using this cell design allow investigation of the changes in the LiMn2O4 structure during charge and discharge. We describe the variation in lattice parameters along the voltage plateaus and consider the structural changes in terms of the electrochemical results on each cell. Kinetic effects of LiMn2O4 phase changes are also addressed. Applications of the in-situ cell to other compounds such as LiCoO2 cathodes and carbon anodes are presented as well.

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