scholarly journals Edge and Notch Detection in a Plate Using Time Reversal Process of Leaky Lamb Waves

2021 ◽  
Vol 12 (1) ◽  
pp. 228
Author(s):  
Jean-Christophe Vallée ◽  
Marie-Aude Ploix ◽  
François Baqué ◽  
Matthieu Cavaro ◽  
Jean-François Chaix
Keyword(s):  
Energy Method ◽  
Time Reversal ◽  
Direct Problem ◽  
Lamb Waves ◽  
Reflected Waves ◽  
Preliminary Step ◽  
First Case ◽  
Element Simulation ◽  
Leaky Lamb Waves ◽  
First Time

Leaky Lamb waves are proven effective to carry out nondestructive testing especially on parallel and immersed plates. To detect and localize defects in such a set, this work associates for the first time the topological energy method and leaky Lamb waves. This methodology is applied in a single immersed plate to validate its application. Firstly, Lamb mode A1 is generated in the plate, and the reflected waves on the defect are measured. A first case is examined where the edge is considered as a defect to be localized. Then, measurements are taken on a plate where a notch is machined. The measurements are time reversed and reinjected in a finite-element simulation. The results are then correlated with the direct problem of the topological energy method that is also simulated. In both cases, the defects are precisely localized on the energy images. This work is the preliminary step to an application of the topological energy method to a set of two parallel and immersed plates where the research defect is located in the second plate.

scholarly journals First case report of acute cholangitis secondary to Cronobacter sakazakii

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Syeda Sahra ◽  
Abdullah Jahangir ◽  
Neville Mobarakai ◽  
Allison Glaser ◽  
Ahmad Jahangir ◽  
...  
Keyword(s):  
Acute Cholangitis ◽  
Tube Placement ◽  
Cronobacter Sakazakii ◽  
First Case ◽  
Shunt Procedure ◽  
Intrahepatic Portosystemic Shunt ◽  
History Of ◽  
Cholecystostomy Tube ◽  
Percutaneous Cholecystostomy Tube ◽  
First Time

Abstract Introduction Cronobacter sakazakii is an opportunistic Gram-negative, rod-shaped bacterium which may be a causative agent of meningitis in premature infants and enterocolitis and bacteremia in neonates and adults. While there have been multiple cases of C. sakazakii infections, there have been no acute cholangitis cases reported in humans. Case presentation An 81-year-old male with a past medical history of basal cell carcinoma, alcoholic liver cirrhosis, transjugular intrahepatic portosystemic shunt procedure, complicated by staphylococcus bacteremia, pituitary tumor, glaucoma, and hypothyroidism presented to the emergency room with the complaint of diffuse and generalized 10/10 abdominal pain of 1 day’s duration. There was a concern for pancreatitis, acute cholangitis, and possible cholecystitis, and the patient underwent a percutaneous cholecystostomy tube placement. Blood cultures from admission and biliary fluid cultures both grew C. sakazakii. The patient was treated with a carbapenem and clinically improved. Conclusions The case study described a patient with multiple medical comorbidities that presented with C. sakazakii bacteremia and cholangitis. While this bacterium has been implicated in other infections, we believe this is the first time the bacteria is being documented to have caused acute cholangitis.

Optimization of thermal conductivity in composites loaded with the solid-solid phase-change materials

2018 ◽  
Vol 25 (6) ◽  
pp. 1157-1165
Author(s):  
Taoufik Mnasri ◽  
Adel Abbessi ◽  
Rached Ben Younes ◽  
Atef Mazioud
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Solid Phase ◽  
Spherical Inclusions ◽  
First Case ◽  
The Matrix ◽  
Composite Conductivity ◽  
First Time

AbstractThis work focuses on identifying the thermal conductivity of composites loaded with phase-change materials (PCMs). Three configurations are studied: (1) the PCMs are divided into identical spherical inclusions arranged in one plane, (2) the PCMs are inserted into the matrix as a plate on the level of the same plane of arrangement, and (3) the PCMs are divided into identical spherical inclusions arranged periodically in the whole matrix. The percentage PCM/matrix is fixed for all cases. A comparison among the various situations is made for the first time, thus providing a new idea on how to insert PCMs into composite matrices. The results show that the composite conductivity is the most important consideration in the first case, precisely when the arrangement plane is parallel with the flux and diagonal to the entry face. In the present work, we are interested in exploring the solid-solid PCMs. The PCM polyurethane and a wood matrix are particularly studied.

Laser-induced thermoelastic Leaky Lamb waves at the fluid–solid interface

2011 ◽  
Vol 105 (2) ◽  
pp. 379-386 ◽  
Author(s):  
Chen Guang Xu ◽  
Bai Qiang Xu ◽  
Gui Dong Xu
Keyword(s):  
Lamb Waves ◽  
Solid Interface ◽  
Leaky Lamb Waves

scholarly journals LITOS – a new balloon-borne instrument for fine-scale turbulence soundings in the stratosphere

2011 ◽  
Vol 4 (1) ◽  
pp. 55-66 ◽  
Author(s):  
A. Theuerkauf ◽  
M. Gerding ◽  
F.-J. Lübken
Keyword(s):  
High Reliability ◽  
Sampling Rate ◽  
Atmospheric Physics ◽  
Turbulent Layer ◽  
First Case ◽  
Radiosonde Station ◽  
Wind Measurements ◽  
Scale Turbulence ◽  
Constant Temperature Anemometer ◽  
First Time

Abstract. We have developed a new compact balloon payload called LITOS (Leibniz-Institute Turbulence Observations in the Stratosphere) for high resolution wind turbulence soundings in the stratosphere up to 35 km altitude. The wind measurements are performed using a constant temperature anemometer (CTA) with a vertical resolution of ~2.5 mm, i.e. 2 kHz sampling rate at 5 m/s ascent speed. Thereby, for the first time, it is possible to study the entire turbulence spectrum down to the viscous subrange in the stratosphere. Including telemetry, housekeeping, batteries and recovery unit, the payload weighs less than 5 kg and can be launched from any radiosonde station. Since autumn 2007, LITOS has been successfully launched several times from the Leibniz-Institute of Atmospheric Physics (IAP) in Kühlungsborn, Germany (54° N, 12° E). Two additional soundings were carried out in 2008 and 2009 in Kiruna, Sweden (67° N, 21° E) as part of the BEXUS program (Balloon-borne EXperiments for University Students). We describe here the basic principle of CTA measurements and prove the validity of this method in the stratosphere. A first case study allows a clear distinction between non-turbulent regions and a turbulent layer with a thickness of some tens of meters. Since our measurements cover the transition between the inertial and viscous subrange, energy dissipation rates can be calculated with high reliability.

scholarly journals Study of Lamb Waves for Non-Destructive Testing Behind Screens

2018 ◽  
Vol 170 ◽  
pp. 03005 ◽  
Author(s):  
P. Kauffmann ◽  
M.-A. Ploix ◽  
J.-F. Chaix ◽  
C. Gueudré ◽  
G. Corneloup ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Lamb Waves ◽  
Nuclear Industry ◽  
Liquid Sodium ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Leaky Lamb Waves ◽  
Short Time ◽  
And Control ◽  
Non Destructive

The inspection and control of sodium-cooled fast reactors (SFR) is a major issue for the nuclear industry. Ultrasonic solutions are under study because of the opacity of liquid sodium. In this paper, the use of leaky Lamb waves is considered for non-destructive testing (NDT) on parallel and immersed structures assimilated as plates. The first phase of our approach involved studying the propagation properties of leaky Lamb waves. Equations that model the propagation of Lamb waves in an immersed plate were solved numerically. The phase velocity can be experimentally measured using a two dimensional Fourier transform. The group velocity can be experimentally measured using a short-time Fourier transform technique. Attenuation of leaky Lamb waves is mostly due to the re-emission of energy into the surrounding fluid, and it can be measured by these two techniques.

NDE OF COMPOSITES USING LEAKY LAMB WAVES (LLW)

2001 ◽  
Vol 17 (2) ◽  
pp. 91-119 ◽  
Author(s):  
YOSEPH BAR-COHEN ◽  
SHYH-SHIUH LIH ◽  
AJIT K. MAL
Keyword(s):  
Lamb Waves ◽  
Leaky Lamb Waves

The Catholic and Jewish Court: Explaining the Absence of Protestants on the Nation's Highest Judicial Body

2012 ◽  
Vol 27 (2) ◽  
pp. 359-396
Author(s):  
Zachary Baron Shemtob
Keyword(s):  
United States ◽  
United States Supreme Court ◽  
The United States ◽  
Bill Clinton ◽  
Prima Facie ◽  
United States Supreme ◽  
Judicial Appointments ◽  
First Case ◽  
First Time ◽  
Roman Catholics

Following the 2006 retirement of Sandra Day O'Connor and the confirmation of Samuel Alito to succeed her, Roman Catholics formed a majority on the United States Supreme Court for the first time in this institution's 210-year history. This Catholic majority was further strengthened by the appointment of Sonia Sotomayor in 2009. Perhaps even more remarkably, by the time of Elena Kagan's first case in October of 2010, not a single Protestant sat on the nation's highest judicial body.By way of comparison, in 1960 the Court consisted of seven Protestants, one Catholic and one Jew; in 1985, eight Protestants and one Catholic sat on the Court. This phenomenon is further reflected in judicial appointments. Since 1985, only one Protestant has been appointed,4 Justice David Souter, compared to seven Catholics and three Jews. The prima facie reason for this transformation is simple: President Reagan began the Protestant erosion by appointing two Catholics; George H.W. Bush followed by appointing a Catholic; and Bill Clinton, George W. Bush, and Barack Obama chose only Jewish and Catholic nominees. The deeper reasons, which are considerably more complex, are the focus of this article.

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