scholarly journals Piezoelectric Sensor Signal Analysis after Interface Changes between the Sensor and the Structure under Monitoring

Proceedings ◽  
2019 ◽  
Vol 42 (1) ◽  
pp. 21
Author(s):  
Pedro Giroto ◽  
Paulo R. Aguiar ◽  
Felipe A. Alexandre ◽  
Pedro Oliveira Junior ◽  
Martin Aulestia Vieira ◽  
...  
Keyword(s):  
Signal Analysis ◽  
Digital Signal ◽  
Piezoelectric Sensor ◽  
Piezoelectric Transducers ◽  
Response Behavior ◽  
Industrial Environment ◽  
Future Studies ◽  
The Subject ◽  
Non Destructive ◽  
Steel Body

This study aims to show the influences of the sensor installation interface in the industrial environment. This contribution is focused on analyzing the response behavior of piezoelectric transducers subjected to successive installations, using digital signal processing and non-destructive structural health monitoring (SHM) techniques. Tests were performed to simulate the installation conditions of a piezoelectric sensor, which was coupled to a holder carrying a steel body and submitted to successive reinstallations. Different signals were obtained for each installation, and the results can bring initial elucidations on the subject and pave the way for future studies.

Biographical Studies of G.I. Gurdjieff

2016 ◽  
Vol 11 (1) ◽  
pp. 10-35
Author(s):  
Joseph Azize
Keyword(s):  
Comparative Research ◽  
Source Material ◽  
Future Studies ◽  
The Third ◽  
The Subject

The various published biographies and biographical notices of G.I. Gurdjieff (c.1865-1949) are of diverse style, quantity and content. While some have made considerable contributions to the subject, most attempts have reacted for or against Gurdjieff’s status as what might call an ‘Enlightened Master’. Little biographical writing on Gurdjieff has questioned the scope, reliability and prejudices of the sources. Further, possible resources have been neglected. The development in Gurdjieff’s ideas is often overlooked, his life is not sufficiently related to that development, and the lack of comparative research has failed to highlight Gurdjieff’s unique contributions. This article is structured in four parts. The first is an introduction, followed by an overview of existing biographical studies of Gurdjieff. The third part addresses bias in these studies, and this is followed by suggestions for future studies. It is concluded that fieldwork regarding the biography of Gurdjieff has been hampered by imperfect methodology. However, with better use of the source material, some of which has only recently been discovered, and a rigorous use of sources, a more balanced and nuanced picture of Gurdjieff’s life, and the development of his ideas and methods, should emerge.

Non-Destructive Testing of Thermoplastic Carbon Composite Structures

2020 ◽  
Vol 2020 (1) ◽  
pp. 34-52
Author(s):  
Rafał Szymański
Keyword(s):  
Composite Structures ◽  
Ultrasonic Method ◽  
Composite Panel ◽  
Aviation Industry ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Pulse Technique ◽  
Thermoplastic Matrix ◽  
The Subject ◽  
Non Destructive

AbstractThe article is in line with the contemporary interests of companies from the aviation industry. It describes thermoplastic material and inspection techniques used in leading aviation companies. The subject matter of non-destructive testing currently used in aircraft inspections of composite structures is approximated and each of the methods used is briefly described. The characteristics of carbon preimpregnates in thermoplastic matrix are also presented, as well as types of thermoplastic materials and examples of their application in surface ship construction. The advantages, disadvantages and limitations for these materials are listed. The focus was put on the explanation of the ultrasonic method, which is the most commonly used method during the inspection of composite structures at the production and exploitation stage. Describing the ultrasonic method, the focus was put on echo pulse technique and the use of modern Phased Array heads. Incompatibilities most frequently occurring and detected in composite materials with thermosetting and thermoplastic matrix were listed and described. A thermoplastic flat composite panel made of carbon pre-impregnate in a high-temperature matrix (over 300°C), which was the subject of the study, was described. The results of non-destructive testing (ultrasonic method) of thermoplastic panel were presented and conclusions were drawn.

Extending Acoustic Microscopy for Comprehensive Failure Analysis Applications

2010 ◽  
Author(s):  
Sebastian Brand ◽  
Matthias Petzold ◽  
Peter Czurratis ◽  
Peter Hoffrogge
Keyword(s):  
Image Processing ◽  
Failure Analysis ◽  
Signal Analysis ◽  
Flip Chip ◽  
Fault Isolation ◽  
Acoustic Microscopy ◽  
Specific Information ◽  
Full Potential ◽  
Time Frequency ◽  
Non Destructive

Abstract In industrial manufacturing of microelectronic components, non-destructive failure analysis methods are required for either quality control or for providing a rapid fault isolation and defect localization prior to detailed investigations requiring target preparation. Scanning acoustic microscopy (SAM) is a powerful tool enabling the inspection of internal structures in optically opaque materials non-destructively. In addition, depth specific information can be employed for two- and three-dimensional internal imaging without the need of time consuming tomographic scan procedures. The resolution achievable by acoustic microscopy is depending on parameters of both the test equipment and the sample under investigation. However, if applying acoustic microscopy for pure intensity imaging most of its potential remains unused. The aim of the current work was the development of a comprehensive analysis toolbox for extending the application of SAM by employing its full potential. Thus, typical case examples representing different fields of application were considered ranging from high density interconnect flip-chip devices over wafer-bonded components to solder tape connectors of a photovoltaic (PV) solar panel. The progress achieved during this work can be split into three categories: Signal Analysis and Parametric Imaging (SA-PI), Signal Analysis and Defect Evaluation (SA-DE) and Image Processing and Resolution Enhancement (IP-RE). Data acquisition was performed using a commercially available scanning acoustic microscope equipped with several ultrasonic transducers covering the frequency range from 15 MHz to 175 MHz. The acoustic data recorded were subjected to sophisticated algorithms operating in time-, frequency- and spatial domain for performing signal- and image analysis. In all three of the presented applications acoustic microscopy combined with signal- and image processing algorithms proved to be a powerful tool for non-destructive inspection.

IIR implementation of wavelet decomposition for digital signal analysis

1992 ◽  
Vol 28 (5) ◽  
pp. 513 ◽  
Author(s):  
F. Argenti ◽  
G. Benelli ◽  
A. Sciorpes
Keyword(s):  
Signal Analysis ◽  
Wavelet Decomposition ◽  
Digital Signal

Laser-Generated Ultrasonic Technique for Inspecting Delamination in CFRP

2006 ◽  
Vol 321-323 ◽  
pp. 968-971
Author(s):  
Won Su Park ◽  
Sang Woo Choi ◽  
Joon Hyun Lee ◽  
Kyeong Cheol Seo ◽  
Joon Hyung Byun
Keyword(s):  
High Frequency ◽  
Ultrasonic Method ◽  
Piezoelectric Sensor ◽  
Frequency Component ◽  
Guided Wave ◽  
Center Frequency ◽  
High Frequency Component ◽  
Ultrasonic Technique ◽  
Non Destructive Evaluation ◽  
Non Destructive

For improving quality of a carbon fiber reinforced composite material (CFRP) by preventing defects such as delamination and void, it should be inspected in fabrication process. Novel non-contacting evaluation technique is required because the transducer should be contacted on the CFRP in conventional ultrasonic technique during the non-destructive evaluation and these conventional contact techniques can not be applied in a novel fiber placement system. For the non-destructive evaluation of delamination in CFRP, various methods for the generation and reception of laser-generated ultrasound are applied using piezoelectric transducer, air-coupled transducer, wavelet transform technique etc. The high frequency component of laser-generated guided wave received with piezoelectric sensor disappeared after propagating through delamination region. Air-coupled transducer was tried to be adopted in reception of laser-generated guided wave generated by using linear slit array in order to generate high frequency guided wave with a frequency of 1.1 MHz. Nevertheless, it was failed to receive high frequency guided wave in using air-coupled transducer and linear slit array. Transmitted laser-generated ultrasonic wave was received on back-wall and its frequency was analyzed to establish inspecting technique to detect delamination by non-contact ultrasonic method. In a frequency spectrum analysis, intensity ratio of low frequency and center frequency was approvable parameter to detect delamination.

scholarly journals Knowledge of semantic categories in normal aged: Influence of education

2007 ◽  
Vol 1 (2) ◽  
pp. 166-172 ◽  
Author(s):  
Karla Shimura Barea ◽  
Leticia Lessa Mansur
Keyword(s):  
Semantic Memory ◽  
Cognitive Processing ◽  
Verbal Fluency ◽  
Semantic Knowledge ◽  
Future Studies ◽  
Semantic Categories ◽  
The Subject ◽  
Naming Test ◽  
Semantic Attributes ◽  
Fluency Test

Abstract Semantic memory seems to resist the effects of time, remaining stable even in more advanced ages. Objective: To verify the effect of schooling level on semantic knowledge (non-living items) in normal aged. Method: 48 aged individuals were divided into three groups (based on schooling) and evaluated. Three tests were applied: verbal fluency, naming and figure classification. Results: We verified that the group with greater schooling (>8 years) differed to the illiterate and low schooling groups in most of the tasks, evoking more items in verbal fluency, correctly naming more items and presenting a greater number of "formal categories". Discussion: In the verbal fluency test, this difference could be explained by the types of strategies used by the individuals to recall words. In relation to the naming test, the effect could be attributed to limitation in the vocabulary and cognitive processing skills needed to search for semantic attributes of the figures. In categorization, this type of classification is dependent on scholastic learning. Conclusion: We concluded that both illiterate elderly and those having a low schooling level, presented poorer performance in semantic memory tests compared to the aged with a higher level of schooling. The similar behavior evidenced between illiterate and low schooling groups is intriguing. It remains unclear whether the low schooling group behaved like the illiterates or vice-a-versa. This unanswered question remains the subject of future studies.

scholarly journals Is There a Link between Oropharyngeal Microbiome and Schizophrenia? A Narrative Review

2022 ◽  
Vol 23 (2) ◽  
pp. 846
Author(s):  
Stanislas Martin ◽  
Audrey Foulon ◽  
Wissam El Hage ◽  
Diane Dufour-Rainfray ◽  
Frédéric Denis
Keyword(s):  
Periodontal Disease ◽  
Research Team ◽  
Oral Microbiome ◽  
Oral Microbiota ◽  
Future Studies ◽  
The Subject ◽  
The Moment ◽  
The Impact ◽  
The Brain

The study aimed to examine the impact of the oropharyngeal microbiome in the pathophysiology of schizophrenia and to clarify whether there might be a bidirectional link between the oral microbiota and the brain in a context of dysbiosis-related neuroinflammation. We selected nine articles including three systemic reviews with several articles from the same research team. Different themes emerged, which we grouped into 5 distinct parts concerning the oropharyngeal phageome, the oropharyngeal microbiome, the salivary microbiome and periodontal disease potentially associated with schizophrenia, and the impact of drugs on the microbiome and schizophrenia. We pointed out the presence of phageoma in patients suffering from schizophrenia and that periodontal disease reinforces the role of inflammation in the pathophysiology of schizophrenia. Moreover, saliva could be an interesting substrate to characterize the different stages of schizophrenia. However, the few studies we have on the subject are limited in scope, and some of them are the work of a single team. At this stage of knowledge, it is difficult to conclude on the existence of a bidirectional link between the brain and the oral microbiome. Future studies on the subject will clarify these questions that for the moment remain unresolved.

scholarly journals Photoacoustic spectroscopy allows to make correlations between blood p450 cytochrome and glycemia in type 1 experimental diabetes

2021 ◽  
Vol 2090 (1) ◽  
pp. 012152
Author(s):  
L I Olvera ◽  
G C Villanueva ◽  
E Romero ◽  
A Cruz
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Diabetes Complications ◽  
Venous Blood ◽  
Future Studies ◽  
Patients With Diabetes ◽  
Male Wistar Rats ◽  
Experimental Type ◽  
Non Destructive

Abstract Diabetes is the eight-cause death worldwide. The cause of death of patients with diabetes is mostly the long-term complications, that are not easy to detect opportunely. In previous studies, we applied photoacoustic spectroscopy (PAS), a non-destructive technique, to detect several components of blood. The goal of the study was to apply the phase-resolved method (PRM), on blood optical absorption spectra obtained by PAS, to analyse blood components in experimental type 1 diabetes. Diabetes was produced in male Wistar rats through the administrations of streptozotocin (STZ). Venous blood samples were obtained one, two, four and eight weeks after STZ. PRM applied to spectra allowed to detect p450 cytochrome. There was a significant and positive correlation between glycaemia and p450 cytochrome (p=0.001). Since p450 cytochrome participates in detoxification function, results indicate that glycaemia could affect detoxification. It will be important in future studies to study the implications of those results on the development of diabetes complications. The novelty of the study was to use PAS to find out if there was any correlation between spectroscopy variables and glycaemia. It is concluded that PRM applied to PAS is a suitable technology to study p450 cytochrome in diabetes.

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