Conservation of Tin and Lead Foil

1918 ◽  
Vol 5 (12) ◽  
pp. 1289
Keyword(s):  
Lead Foil

scholarly journals Does the addition of a lead foil to digital radiographic receptors influence image contrast and approximal caries lesions diagnosis?

2020 ◽  
Vol 49 (4) ◽  
pp. 20190384
Author(s):  
Rocharles Cavalcante Fontenele ◽  
Yuri Nejaim ◽  
Amanda Farias Gomes ◽  
Hugo Gaêta-Araujo ◽  
Francisco Haiter-Neto ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Image Contrast ◽  
Contrast Variation ◽  
Radiographic Images ◽  
Posterior Teeth ◽  
Diagnostic Values ◽  
Caries Lesions ◽  
Approximal Caries ◽  
Gray Values ◽  
Lead Foil

Objectives: To access the influence of the addition of a lead foil to intraoral digital radiographic receptors on image contrast and approximal caries lesions diagnosis. Methods: 40 posterior teeth were distributed in silicone phantoms composed of two premolars, two molars and a non-test canine. Radiographic images of the phantoms were obtained with and without the incorporation of a lead foil, using the Digora Optime and Digora Toto systems. Four observers scored the images for the presence of caries lesions, using a 5-point scale. Images of an aluminum step wedge were acquired with and without the incorporation of a lead foil. Gray values and standard deviation of gray values were calculated in different thickness of the step wedge and, then, contrast variation was calculated. Results: Presence of a lead foil did not influence caries lesions diagnostic values, regardless of the type of digital system (p > 0.05). In general, the objective analysis was not influenced by the presence of a lead foil in any of the tested systems (p > 0.05). However, Digora Toto images showed greater gray values, lower standard deviation of gray values and lower contrast variation, regardless of the presence of the lead foil (p < 0.05). Conclusions: The addition of a lead foil to intraoral digital receptors did not influence image contrast nor caries lesions diagnosis.

Permeation of Electrolytically Generated Hydrogen and Tritium Atoms through Lead

1971 ◽  
Vol 49 (14) ◽  
pp. 2406-2411 ◽  
Author(s):  
Bansi L. Muju ◽  
Frank R. Smith
Keyword(s):  
Current Density ◽  
Separation Factor ◽  
Room Temperature ◽  
Alkaline Media ◽  
Gas Evolution ◽  
Hydrogen Atoms ◽  
Metal Lattice ◽  
Acidic And Alkaline Media ◽  
A Current ◽  
Lead Foil

Radiochemical and electrochemical evidence is presented that electrochemically generated tritium and hydrogen atoms permeate through lead foil at measureable rates at room temperature. The permeation process is controlled by diffusion through the metal lattice, Fick's First Law being obeyed by both H and 3H atoms. Using earlier measurements of the diffusivity of H in Pb, H and 3H concentrations of 4 × 10−7 and 9 × 10−13 g-atom cm−3 are computed for a current density of 53 mA cm−2 at the Pb cathode surface.The overall hydrogen-tritium separation factor, ST is apparently 0.3 ± 0.15, in contrast to Bockris and Srinivasan's 6.7 and 7.2 for cathodic gas evolution from acidic and alkaline media, respectively. Reasons are suggested for this large difference.

Gamma-ray sensitivity and shielding of a neutron imaging plate

1999 ◽  
Vol 32 (5) ◽  
pp. 878-882 ◽  
Author(s):  
Y. Karasawa Haga ◽  
S. Kumazawa ◽  
N. Niimura
Keyword(s):  
Thermal Neutron ◽  
Energy Dependence ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Neutron Imaging ◽  
Atomic Energy ◽  
Imaging Plate ◽  
Energy Research ◽  
Experimental Hall ◽  
Lead Foil

The energy dependence of gamma-ray sensitivity of a neutron imaging plate (NIP) has been measured. The gamma-ray sensitivity is equivalent to one half that of a thermal neutron at a gamma-ray energy less than 300 keV, and 1/40 at greater than 300 keV. The shielding of the NIP, by lead, from gamma rays in the experimental hall of the reactor JRR-3M of the Japan Atomic Energy Research Institute (JAERI) was measured. It was found that lead of thickness 40 mm is sufficient to reduce the gamma-ray background to 1/10 on a normalized scale. Covering the NIP with lead foil of thickness 1 mm results in a decrease of the gamma-ray background without reduction of the neutron signal.

scholarly journals Influence of the incorporation of a lead foil to intraoral digital receptors on the image quality and root fracture diagnosis

2019 ◽  
Vol 48 (6) ◽  
pp. 20180369 ◽  
Author(s):  
Amanda Farias Gomes ◽  
Yuri Nejaim ◽  
Rocharles Cavalcante Fontenele ◽  
Francisco Haiter-Neto ◽  
Deborah Queiroz Freitas
Keyword(s):  
Image Quality ◽  
Control Group ◽  
Human Teeth ◽  
Radiographic Images ◽  
Root Fracture ◽  
Vertical Root Fracture ◽  
Diagnostic Values ◽  
Fracture Diagnosis ◽  
Lead Foil

Objective: To evaluate the quality of images obtained with the addition of a lead foil to intraoral digital receptors. Methods: Radiographic images of 34 single-rooted human teeth - 19 with vertical root fracture (VRF) and 15 of the control group - were obtained with and without the addition of a lead foil, using the VistaScan, Express, Digora Optime and Digora Toto systems. Images were evaluated by five observers regarding the diagnosis of VRF, using a 5-point scale. In a second moment, an observer preference analysis related to the presence of the lead foil was performed. Images of an acrylic phantom were also obtained with and without the addition of a lead foil, and the quantities of uniformity, grey value and standard deviation of grey values were obtained. Results: There were no significant differences in the VRF diagnostic values, considering the presence of the lead foil. Regarding the image quality preference, the observers preferred images acquired with the lead foil for all systems tested, but with greater values for Digora Optime (61.33%) and Express (61.33%). The presence of the lead foil did influence the image uniformity in all systems tested ( p < 0.05). Moreover, the lead foil increased the mean of grey values for Digora Optime and Express images ( p < 0.05), however it did not influence the SD in any of the digital systems ( p > 0.05). Conclusion: The addition of a lead foil to intraoral digital receptors produces a positive effect in the image quality objectively detected by means of uniformity and subjective visual preference.

The Measurement and Effects of Edge Sharpness on the Flow Coefficients of Standard Orifices

1973 ◽  
Vol 95 (2) ◽  
pp. 271-274 ◽  
Author(s):  
K. A. Crockett ◽  
E. L. Upp
Keyword(s):  
Impression Technique ◽  
Edge Sharpness ◽  
Work Done ◽  
Lead Foil

An investigation of the lead foil impression technique of determining orifice edge-sharpness and the resultant effects on orifice coefficient of the rounding of the square-edge as determined by water calibration are discussed. The data to date are encouraging and correlate well with similiar work done originally in Germany and more recently in England.

LEAD FOIL ON WINE BOTTLES

The Lancet ◽  
1987 ◽  
Vol 330 (8573) ◽  
pp. 1473-1474 ◽  
Author(s):  
Vincent Marks ◽  
Andrew Taylor
Keyword(s):  
Lead Foil

PROTECTIVE VALUES OF LEAD FOIL

1950 ◽  
Vol 61 (5) ◽  
pp. 864
Author(s):  
ROBERT S. LANDAUER
Keyword(s):  
Lead Foil

Water Impervious URD Cable Having Lead Foil on Conductor and on Core

1986 ◽  
Vol PER-6 (1) ◽  
pp. 33-34
Author(s):  
H. Furusawa ◽  
T. Uematsu ◽  
K. Ishihara ◽  
M. Mizuno ◽  
Y. Hane
Keyword(s):  
Lead Foil

scholarly journals Radiopacity of calcium hydroxide cement compared with human tooth structure

2004 ◽  
Vol 12 (4) ◽  
pp. 290-293 ◽  
Author(s):  
Karina Lopes Devito ◽  
Ana Isabel Ortega ◽  
Francisco Haiter-Neto
Keyword(s):  
Calcium Hydroxide ◽  
Analysis Of Variance ◽  
The Other ◽  
Human Tooth ◽  
Equivalent Thickness ◽  
Secondary Caries ◽  
Tooth Structure ◽  
Base Materials ◽  
Significant Difference ◽  
Lead Foil

AIMS: All materials added to teeth should present an adequate radiopacity to allow the detection of secondary caries. Usually, in extensive cavities, base materials like calcium hydroxide cement are used for the purpose of protecting the pulp. In an attempt to improve the efficiency of radiographic detection of this material, this study aimed to determine the radiopacity of three calcium hydroxide cements and to compare the radiopacity of these materials with dentin and enamel. METHODS: Radiographs were taken of 1-mm thick specimens of three calcium hydroxide cements: Hydro-C, Dycal and Life, an aluminium stepwedge, a lead foil, and one 1-mm thick human tooth slice. Densitometric measurements were obtained after radiographic processing. The radiopacity values of the calcium hydroxide cements, dentin and enamel were expressed in terms of the equivalent thickness of aluminium. RESULTS: The analysis of variance indicated statistically significant difference only for Life, which presented the lowest radiopacity when compared to the other cements. However, all cements and enamel possessed a radiopacity equivalent to 2mm Al, while dentin presented a radiopacity equivalent to 1mm Al. CONCLUSION: All tested cements presented a similar radiopacity to that of enamel and they meet the ISO 4049 specifications.

Sign in / Sign up

Export Citation Format

Share Document