Dry Effect of Cementitious Materials on Testing Results of X-Ray CT

In this study three-dimensional X-ray computed tomography (X-ray CT) is used to investigate the testing results differences of cement paste and mortar before and after drying. It can be found that the mean gray values of paste and mortar before drying are bigger than after drying, and the impact of drying on cement paste is more serious than mortar. In addition, the porosity of non-drying cement paste and mortar is 1.10% and 0.43%, while that of drying cement paste and mortar is 1.55% and 0.70%, respectively. So, the porosity of paste and mortar markedly increases after drying process. The numbers of pores of paste and mortar sharply increase after drying process in particular between 0.01mm3 and 0.1mm3. The impact of drying on smaller pores is more serious than bigger pores.

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X-Ray Computed Tomography Studies of 3D Meso-Defect Volume Distribution Changes of Cement Paste due to Carbonation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.163-167.3061 ◽

2010 ◽

Vol 163-167 ◽

pp. 3061-3066 ◽

Cited By ~ 2

Author(s):

Jian De Han ◽

Gang Hua Pan ◽

Wei Sun ◽

Cai Hui Wang ◽

Hui Rong

Keyword(s):

Computed Tomography ◽

Cement Paste ◽

Volume Fraction ◽

Three Dimensional ◽

Volume Distribution ◽

X Ray ◽

Before And After ◽

X Ray Computed ◽

Non Destructive ◽

Defect Volume

X-ray computed tomography (XCT), a non-destructive test, was used to study three dimensional (3D) meso-defect volume distribution changes of cement paste due to carbonation. The 3D meso-defect volume from 0.02mm3 ~5mm3 before and after carbonation was analyzed through add-on modules of 3D defect analysis. The experimental results show that the meso-defect volume fraction before and after carbonation are 0.7685% and 2.44%, respectively. After carbonation, the smaller defect increased significantly than the bigger defect.

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X-ray Computed Tomography Method for Macroscopic Structural Property Evaluation of Active Twist Composite Blades

Aerospace ◽

10.3390/aerospace8120370 ◽

2021 ◽

Vol 8 (12) ◽

pp. 370

Author(s):

Joon H. Ahn ◽

Hyun J. Hwang ◽

Sehoon Chang ◽

Sung Nam Jung ◽

Steffen Kalow ◽

...

Keyword(s):

Computed Tomography ◽

Structural Properties ◽

Digital Image ◽

Torsional Rigidity ◽

Three Dimensional ◽

Measured Data ◽

X Ray ◽

X Ray Computed ◽

Active Twist ◽

The Impact

This paper describes an evaluation of the structural properties of the next-generation active twist blade using X-ray computed tomography (CT) combined with digital image processing. This non-destructive testing technique avoids the costly demolition of the blade structure. The CT scan covers the whole blade region, including the root, transition, and tip regions, as well as the airfoil blade regions, in which there are spanwise variations in the interior structural layout due to the existence of heavy instrumentation. The three-dimensional digital image data are processed at selected radial stations, and finite element beam cross-section analyses are conducted to evaluate the structural properties of the blade at the macroscopic level. The fidelity of the digital blade model is first assessed by correlating the estimated blade mass with the measured data. A separate mechanical measurement is then carried out to determine the representative elastic properties of the blade and to verify the predicted results. The agreement is found to be good to excellent for the mass, elastic axis, flap bending, and torsional rigidity. The discrepancies are less than 2.0% for the mass and elastic axis locations, and about 8.1% for the blade stiffness properties, as compared with the measured data. Finally, a sensitivity analysis is conducted to clarify the impact of modeling the sensor and actuator cables, nose weight, and manufacturing imperfections on the structural properties of the blade.

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Quantification of thoracic volumes by three-dimensional imaging

Journal of Applied Physiology ◽

10.1152/jappl.1987.62.2.591 ◽

1987 ◽

Vol 62 (2) ◽

pp. 591-598 ◽

Cited By ~ 29

Author(s):

S. Krayer ◽

K. Rehder ◽

K. C. Beck ◽

P. D. Cameron ◽

E. P. Didier ◽

...

Keyword(s):

Three Dimensional ◽

Thoracic Cavity ◽

Volume Changes ◽

X Ray ◽

Relative Contribution ◽

Before And After ◽

Residual Capacity ◽

X Ray Computed ◽

Trapped Gas ◽

Gas Volume

End-expiratory thoracic cavity volume (Vthx) was measured in eight volunteers lying supine by three-dimensional X-ray computed tomography using the Dynamic Spatial Reconstructor. Untrapped end-expiratory pulmonary gas volume at functional residual capacity (FRC) was determined by nitrogen clearance. Both measurements were done before and after induction of anesthesia-paralysis. After induction of anesthesia-paralysis, Vthx and FRC were consistently and significantly (P less than 0.01) reduced by 0.28 +/- 0.22 (SD) and 0.59 +/- 0.24 liter, respectively. The reduction of FRC was larger than the reduction of Vthx (delta Vthx) in six of the eight subjects, a finding suggesting that intrathoracic fluid (blood) plus trapped gas volume (Vtt) increased. Changes in Vthx were partitioned into volume changes from the thoracic rib cage (delta Vrc) and from shape and/or position changes of the diaphragm (delta Vdi). delta Vrc contributed significantly (0.17 +/- 0.15 liter, P less than 0.02) to delta Vthx, whereas delta Vdi contributed only in four of the eight subjects. We conclude that delta Vrc, delta Vdi, and delta Vtt contribute to the reduction of FRC after induction of anesthesia-paralysis in humans; the relative contribution of them varies among subjects.

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Analyzing the Impact of X-Ray Tomography on the Reliability of Integrated Circuits

ISTFA 2015: Conference Proceedings from the 41st International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2015p0154 ◽

2015 ◽

Author(s):

Halit Dogan ◽

Md Mahbub Alam ◽

Navid Asadizanjani ◽

Sina Shahbazmohamadi ◽

Domenic Forte ◽

...

Keyword(s):

Integrated Circuits ◽

Integrated Circuit ◽

3D Imaging ◽

Three Dimensional ◽

Serial Sectioning ◽

Promising Technique ◽

Flash Memories ◽

X Ray ◽

3D Information ◽

The Impact

Abstract X-ray tomography is a promising technique that can provide micron level, internal structure, and three dimensional (3D) information of an integrated circuit (IC) component without the need for serial sectioning or decapsulation. This is especially useful for counterfeit IC detection as demonstrated by recent work. Although the components remain physically intact during tomography, the effect of radiation on the electrical functionality is not yet fully investigated. In this paper we analyze the impact of X-ray tomography on the reliability of ICs with different fabrication technologies. We perform a 3D imaging using an advanced X-ray machine on Intel flash memories, Macronix flash memories, Xilinx Spartan 3 and Spartan 6 FPGAs. Electrical functionalities are then tested in a systematic procedure after each round of tomography to estimate the impact of X-ray on Flash erase time, read margin, and program operation, and the frequencies of ring oscillators in the FPGAs. A major finding is that erase times for flash memories of older technology are significantly degraded when exposed to tomography, eventually resulting in failure. However, the flash and Xilinx FPGAs of newer technologies seem less sensitive to tomography, as only minor degradations are observed. Further, we did not identify permanent failures for any chips in the time needed to perform tomography for counterfeit detection (approximately 2 hours).

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Three‐dimensional X‐ray‐computed tomography of 3300‐ to 6000‐year‐old Citrullus seeds from Libya and Egypt compared to extant seeds throws doubts on species assignments

Plants People Planet ◽

10.1002/ppp3.10220 ◽

2021 ◽

Author(s):

Katherine A. Wolcott ◽

Guillaume Chomicki ◽

Yannick M. Staedler ◽

Krystyna Wasylikowa ◽

Mark Nesbitt ◽

...

Keyword(s):

Computed Tomography ◽

Three Dimensional ◽

X Ray ◽

X Ray Computed

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Cover Feature: Non‐Destructive Three‐Dimensional Imaging of Metal Organic Framework Mixed Matrix Membranes using Lab‐based X‐ray Computed Tomography (Chemistry ‐ Methods 5/2021)

Chemistry–Methods ◽

10.1002/cmtd.202100034 ◽

2021 ◽

Vol 1 (5) ◽

pp. 202-202

Author(s):

Anton Jansson ◽

Ignacio Luz ◽

Ching‐Chang Chung ◽

Mustapha Soukri

Keyword(s):

Computed Tomography ◽

Metal Organic Framework ◽

Three Dimensional ◽

Mixed Matrix Membranes ◽

Mixed Matrix ◽

Three Dimensional Imaging ◽

X Ray ◽

Metal Organic ◽

X Ray Computed ◽

Non Destructive

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Visualizing Fluid Flows With X-Rays

Volume 1: Symposia, Parts A and B ◽

10.1115/fedsm2007-37023 ◽

2007 ◽

Cited By ~ 4

Author(s):

Theodore J. Heindel ◽

Terrence C. Jensen ◽

Joseph N. Gray

Keyword(s):

Computed Tomography ◽

Flow Visualization ◽

Three Dimensional ◽

Fluid Flows ◽

X Rays ◽

Radiographic Images ◽

Optical Access ◽

X Ray ◽

X Ray Computed ◽

Density Map

There are several methods available to visualize fluid flows when one has optical access. However, when optical access is limited to near the boundaries or not available at all, alternative visualization methods are required. This paper will describe flow visualization using an X-ray system that is capable of digital X-ray radiography, digital X-ray stereography, and digital X-ray computed tomography (CT). The unique X-ray flow visualization facility will be briefly described, and then flow visualization of various systems will be shown. Radiographs provide a two-dimensional density map of a three dimensional process or object. Radiographic images of various multiphase flows will be presented. When two X-ray sources and detectors simultaneously acquire images of the same process or object from different orientations, stereographic imaging can be completed; this type of imaging will be demonstrated by trickling water through packed columns and by absorbing water in a porous medium. Finally, local time-averaged phase distributions can be determined from X-ray computed tomography (CT) imaging, and this will be shown by comparing CT images from two different gas-liquid sparged columns.

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Resilience and vulnerability of maternity services in Zimbabwe: a comparative analysis of the effect of Covid-19 and lockdown control measures on maternal and perinatal outcomes, a single-centre cross-sectional study at Mpilo Central Hospital

BMC Pregnancy and Childbirth ◽

10.1186/s12884-021-03884-5 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Clare Shakespeare ◽

Handsome Dube ◽

Sikhangezile Moyo ◽

Solwayo Ngwenya

Keyword(s):

Perinatal Outcomes ◽

Control Measures ◽

Central Hospital ◽

Cross Sectional ◽

Maternity Services ◽

Before And After ◽

The Mean ◽

Significant Change ◽

The Impact ◽

Mpilo Central Hospital

Abstract Background On the 27th of March 2020 the Zimbabwean government declared the Covid-19 pandemic a ‘national disaster’. Travel restrictions and emergency regulations have had significant impacts on maternity services, including resource stock-outs, and closure of antenatal clinics during the lockdown period. Estimates of the indirect impact of Covid-19 on maternal and perinatal mortality was expected it to be considerable, but little data was yet available. This study aimed to examine the impact of Covid-19 and lockdown control measures on non-Covid outcomes in a government tertiary level maternity unit in Bulawayo, Zimbabwe, by comparing maternal and perinatal morbidity and mortality before, and after the lockdown was implemented. Methods This was a retrospective, observational study, using a cross-sectional design to compare routine monthly maternal and perinatal statistics three months before and after Covid-19 emergency measures were implemented at Mpilo Central Hospital. Results Between January-March and April-June 2020, the mean monthly deliveries reduced from 747.3 (SD ± 61.3) in the first quarter of 2020 to 681.0 (SD ± 17.6) during lockdown, but this was not statistically significant, p = 0.20. The Caesarean section rates fell from a mean of 29.8% (SD ± 1.7) versus 28.0% (SD ± 1.7), which was also not statistically significant, p = 0.18. During lockdown, the percentage of women delivering at Mpilo Central Hospital who were booked at the hospital fell from a mean of 41.6% (SD ± 1.1) to 35.8% (SD ± 4.3) which was statistically significant, p = 0.03. There was no significant change, however, in maternal mortality or severe maternal morbidity (such as post-partum haemorrhage (PPH), uterine rupture, and severe preeclampsia/eclampsia), stillbirth rate or special care baby unit admission. There was an increase in the mean total number of early neonatal deaths (ENND) (mean 18.7 (SD ± 2.9) versus 24.0 (SD ± 4.6), but this was not statistically significant, p = 0.32. Conclusions Overall, maternity services at Mpilo showed resilience during the lockdown period, with no significant change in maternal and perinatal adverse outcomes, with the same number of man-hours worked before and during the lockdown Maternal and perinatal outcomes should continue to be monitored to assess the impact of Covid-19 and the lockdown measures as the pandemic in Zimbabwe unfolds. Further studies would be beneficial to explore women’s experiences and understand how bookings and deliveries at local clinics changed during this time.

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Sedimentary Clays as Geopolymer Precursor

International Journal of Engineering Research in Africa ◽

10.4028/www.scientific.net/jera.39.97 ◽

2018 ◽

Vol 39 ◽

pp. 97-111

Author(s):

F. Mostefa ◽

Nasr Eddine Bouhamou ◽

H.A. Mesbah ◽

Salima Aggoun ◽

D. Mekhatria

Keyword(s):

Sodium Hydroxide ◽

Mineralogical Composition ◽

Cementitious Materials ◽

Raw Material ◽

X Ray Diffraction ◽

Calcination Time ◽

Calorimetric Analysis ◽

X Ray ◽

Before And After ◽

Mechanical Performances

This work aims to study the feasibility of making a geopolymer cement based on dredged sediments, from the Fergoug dam (Algeria) and to evaluate their construction potential particularly interesting in the field of special cementitious materials. These sediments due to their mineralogical composition as aluminosilicates; are materials that can be used after heat treatment. Sedimentary clays were characterized before and after calcination by X-ray diffraction, ATG / ATD, spectroscopy (FTIR) and XRF analysis. The calcination was carried out on the raw material sieved at 80 μm for a temperature of 750 ° C, for 3.4 and 5 hours. The reactivity of the calcined products was measured using isothermal calorimetric analysis (DSC) on pastes prepared by mixing an alkaline solution of sodium hydroxide (NaOH) 8 M in an amount allowing to have a Na / Al ratio close to 1 (1: 1). Also, cubic mortar samples were prepared with a ratio L / S: 0.8, sealed and cured for 24 hours at 60 ° C and then at room temperature until the day they were submited to mechanical testing. to check the extent of geopolymerization. The results obtained allowed to optimize the calcination time of 5 hours for a better reactivity of these sediments, and a concentration of 8M of sodium hydroxide and more suitable to have the best mechanical performances.

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