scholarly journals Improving the X-ray Shielding Performance of Tungsten Thin-Film Plates Manufactured Using the Rolling Technology

2021 ◽  
Vol 11 (19) ◽  
pp. 9111
Author(s):  
Seon-Chil Kim
Keyword(s):  
Plate Thickness ◽  
Rolling Process ◽  
Radiation Shielding ◽  
Pure Tungsten ◽  
Peak Voltage ◽  
Cross Sectional ◽  
X Ray ◽  
Different Temperatures ◽  
Rolling Method ◽  
Rolling Technology

X-ray shields used for medical purposes are manufactured using lead, which is inexpensive and easy to manufacture. However, as lead can be a major factor contributing toward environmental contamination, such as lead poisoning, a radiation-shielding plate was manufactured in this study using a tungsten plate, an eco-friendly material, through a rolling process at different temperatures. In addition, the shielding plate produced via the hot-rolling method exhibited better shielding performance than that of the plate produced using the cold-rolling method, and the multilayer structure was well formed, as indicated in the cross-sectional image analysis. Upon applying a peak voltage of 100 kVp to the X-ray tube, the shielding performance observed was 80% and 96% when the plate thickness was 0.1 mm and 0.3 mm, respectively. Therefore, it is expected that, in the future, the pure tungsten-based shield presented in this study will replace lead plates, owing to its superior standardization and reproducibility of the shielding performance.

Research on the Si-Ti High Temperature Oxidation-Resistant Coatings for Tantalum Alloys

2013 ◽  
Vol 785-786 ◽  
pp. 45-51
Author(s):  
Pei Pei Song ◽  
Jun Le ◽  
Feng Ye ◽  
Xiao Cheng Sheng ◽  
Xiao Wei Zhang
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Isothermal Oxidation ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Temperature Oxidation ◽  
X Ray ◽  
Different Temperatures ◽  
Slurry Method ◽  
Sectional Structure

Si-Ti coatings were prepared on the surface of T-222 alloy by fused slurry method at different temperatures (1425-1500°C). Microstructure and composition of the coatings were characterized and analysed through scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), energy dispersive X-ray spectrometry (EDS) respectively. The coating fabricated at 1450°C exhibited excellent structure compatible with high temperature oxidation resistance. Its surface is relatively smooth with few holes and cracks and the main phase on the surface is (Ti, Ta)Si that possesses outstanding corrosion resistance. Moreover, the cross-sectional structure of the coating is smooth and compact which can effectively prevent O2 from permeation. The isothermal oxidation behaviors in pure O2 atmosphere at 1500°C for 2h finally demonstrate that the optimum coating temperature is 1450°C.

Research on Deformation Permeability Changing Law during Snake Rolling Process

2014 ◽  
Vol 788 ◽  
pp. 367-371
Author(s):  
Xiao Jin Liu ◽  
Lian Yun Jiang ◽  
Guo Yuan ◽  
Guo Dong Wang
Keyword(s):  
Steel Plate ◽  
Effective Strain ◽  
Plate Thickness ◽  
Rolling Process ◽  
Speed Ratio ◽  
Roller Speed ◽  
Calculation Results ◽  
Rolling Method ◽  
Thick Steel ◽  
Numerical Calculation Method

In order to refine the microstructure and improve the mechanical properties of the thicker steel plate, the large rolling reduction should be conducted. Confined to the biting angle of rolling mill, the maximum press quantity is constant. The research indicates that shear stress produced in the deformation region during snake rolling process is helpful and the snake rolling method can be used in the thick steel plate production. The effective strain of steel plate with various roller speed ratio, plate thickness, fraction and roller speed was determined by numerical calculation method. By comparison, the effective strain changing law was obtained. The calculation results indicate that compared to traditional rolling process, the effective strain produced in the plate can be improved with the increase of roller speed ratio, and the deformation permeability can also be improved.

scholarly journals Numerical Analysis of the Skew Rolling Process for Rail Axles

2015 ◽  
Vol 60 (1) ◽  
pp. 415-418 ◽  
Author(s):  
Z. Pater ◽  
J. Tomczak ◽  
T. Bulzak
Keyword(s):  
Numerical Modeling ◽  
Effective Strain ◽  
Translational Motion ◽  
Rolling Process ◽  
Simulation Software ◽  
Maximum Diameter ◽  
Cross Sectional ◽  
Rolling Method ◽  
Skew Rolling

Abstract The paper describes a new method for producing stepped rail axles. The method is based on the skew rolling process. With this method, the product is formed by three tapered rolls located every 120° on the perimeter of the billet. Positioned askew to the centerline of the billet, the rolls rotate in the same direction and with the same velocity. At the same time, they get closer together or go apart depending on the desired cross sectional reduction of an axle step. In addition, the workpiece is shifted lengthwise relative to the rolls by the translational motion of the workpiece-holding chuck. In order to verify the designed method for producing rail axles, a series of numerical simulations were performed using the Simufact. Forming v.12 simulation software. The numerical modeling enabled the determination of maps of the effective strain and temperature in the finished product as well as variations in the loads and torques during rolling. The numerical results unambiguously confirm that the skew rolling method can be applied to form parts of considerable dimensions (the modeled axles had a length of 2146 mm and their maximum diameter was 202 mm).

X-Ray Replication of Submicrometer Linewidth Patterns

1977 ◽  
Vol 35 ◽  
pp. 136-137
Author(s):  
Henry I. Smith ◽  
D.C. Flanders
Keyword(s):  
Electron Beam Lithography ◽  
Cross Sectional ◽  
X Ray ◽  
Electron Backscattering ◽  
Spatial Frequencies ◽  
Cross Sectional Profile ◽  
Carbon Foils ◽  
Sectional Profile ◽  
And Control ◽  
Soft Radiation

Scanning electron beam lithography has been used for a number of years to write submicrometer linewidth patterns in radiation sensitive films (resist films) on substrates. On semi-infinite substrates, electron backscattering severely limits the exposure latitude and control of cross-sectional profile for patterns having fundamental spatial frequencies below about 4000 Å(l),Recently, STEM'S have been used to write patterns with linewidths below 100 Å. To avoid the detrimental effects of electron backscattering however, the substrates had to be carbon foils about 100 Å thick (2,3). X-ray lithography using the very soft radiation in the range 10 - 50 Å avoids the problem of backscattering and thus permits one to replicate on semi-infinite substrates patterns with linewidths of the order of 1000 Å and less, and in addition provides means for controlling cross-sectional profiles. X-radiation in the range 4-10 Å on the other hand is appropriate for replicating patterns in the linewidth range above about 3000 Å, and thus is most appropriate for microelectronic applications (4 - 6).

X-ray micro tomography in the scanning electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 106-107 ◽  
Author(s):  
W. Brünger
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Target Surface ◽  
The Body ◽  
X Rays ◽  
Cross Sectional ◽  
X Ray ◽  
Micro Tomography ◽  
Scanning Electron

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.

A STUDY ON THE CORRELATION BETWEEN MORPHOLOGIC ANORMALIES AND LEFT VENTRICULAR DIASTOLIC FUNCTION IN DILATED CARDIO-MYOPATHY

2011 ◽  
pp. 137-144
Author(s):  
Thi Ngoc Ha Hoang ◽  
Anh Vu Nguyen ◽  
Minh Loi Hoang ◽  
Cuu Long Nguyen ◽  
Thi Thuy Hang Nguyen
Keyword(s):  
Pulmonary Artery ◽  
Dilated Cardiomyopathy ◽  
Diastolic Dysfunction ◽  
Diastolic Function ◽  
Pulmonary Arteries ◽  
Left Ventricular ◽  
University Hospital ◽  
Cross Sectional ◽  
X Ray ◽  
Key Words Dilated Cardiomyopathy

Purposes: Describe the morphological and diastolic function of left ventricular changes in the patients with dilated cardiomyopathy (DCM) on US, X-ray findings, and Evaluate the correlation between morphology and diastolic function of left ventricular. Materials and method: Cross sectional study from Dec 2009 to Aug 2010, on 39 patients with dilated cardiomyopathy were evaluated at the University Hospital of Hue College of Medical and Pharmaceutical. Results: 1. X-ray and US findings characteristics of DCM is significantly increased in diameter of L, H and mG; LVM, LVMI, LVDd and LAD. 2. The pression of pulmonary artery has been significantly increased with redistribution pulmonary arteries in 61.5% cases and 23.1% have reversed pulmonary artery distribution. 3. DCM have diastolic dysfunction in 100% patients, including severe disorders to 61.5%; the restrictive dysfunction has ratio E/A>2 and E/Em average was 23.89± 17.23. 4.The correlation between the morphology and function in DCM: the diameter of H and L on the X-ray, LAD and ratio LA/AO on US correlated with the level of diastolic dysfunction (p< 0.05). All three radiographic parameters on the radio standard (H, L, the index Cardio/Thoracic) and LVDd on US have negative correlated with EF and FS with p <0.05. Key words: dilated cardiomyopathy, diastolic dysfunction, cardiac tissue Doppler, reversed pulmonary artery distribution

OSTEOPOROSIS AND RISK FACTORS IN THE PATIENTS ON CHRONIC HEMODIALYSIS

2015 ◽  
pp. 50-58
Author(s):  
Thi Dung Nguyen ◽  
Tam Vo
Keyword(s):  
Quality Of Life ◽  
Risk Factors ◽  
Bone Density ◽  
Region Of Interest ◽  
Cross Sectional Study ◽  
Chronic Hemodialysis ◽  
Cross Sectional ◽  
X Ray ◽  
Density Reduction

Background: The patients on hemodialysis have a significantly decreased quality of life. One of many problems which reduce the quality of life and increase the mortality in these patients is osteoporosis and osteoporosis associated fractures. Objectives: To assess the bone density of those on hemodialysis by dual energy X ray absorptiometry and to examine the risk factors of bone density reduction in these patients. Patients and Method: This is a cross-sectional study, including 93 patients on chronic hemodialysis at the department of Hemodialysis at Cho Ray Hospital. Results: Mean bone densities at the region of interest (ROI) neck, trochanter, Ward triangle, intertrochanter and total neck are 0.603 ± 0.105; 0.583 ± 0.121; 0.811 ± 0.166; 0.489 ± 0.146; 0.723 ± 0.138 g/cm2 respectively. The prevalences of osteoporosis at those ROI are 39.8%, 15.1%; 28%; 38.7%; and 26.9% respectively. The prevalences of osteopenia at those ROI are 54.8%; 46.3%; 60.2%; 45.2% and 62.7% respectively. The prevalence of osteopososis in at least one ROI is 52.7% and the prevalence of osteopenia in at least one ROI is 47.3%. There are relations between the bone density at the neck and the gender of the patient and the albuminemia. Bone density at the trochanter is influenced by gender, albuminemia, calcemia and phosphoremia. Bone density at the intertrochanter is affected by the gender. Bone density at the Ward triangle is influenced by age and albuminemia. Total neck bone density is influenced by gender, albuminemia and phosphoremia. Conclusion: Osteoporosis in patients on chronic hemodialysis is an issue that requires our attention. There are many interventionable risk factors of bone density decrease in these patients. Key words: Osteoporosis, DEXA, chronic renal failure, chronic hemodialysis

Blood Parathyrin and Mineral Metabolism Dynamics. A clinical analyze

2018 ◽  
Vol 69 (10) ◽  
pp. 2754-2758
Author(s):  
Lucretiu Radu ◽  
Mara Carsote ◽  
Ancuta Augustina Gheorghisan Galateanu ◽  
Smaranda Adelina Preda ◽  
Veronica Calborean ◽  
...  
Keyword(s):  
Case Control Study ◽  
Mineral Metabolism ◽  
Lumbar Bone Mineral Density ◽  
Urinary Calcium ◽  
Mineral Density ◽  
Cross Sectional ◽  
X Ray ◽  
Menopausal Women ◽  
Ionic Calcium ◽  
Control Study

Circulating parathyrin (PTH or parthormon) is increased in primary hyperparathyroidism (PHP) in association with high total/ionic calcium (T/I Ca) and others mineral metabolism anomalies. This is a clinical cross-sectional and case-control study analyzing these changes after PHP surgical correction in menopausal women. Baseline parameters were: mean age at diagnosis (59.63�9.6 years), TCa of 10.9�0.7 mg/dL, PTH of 138.02�59.36 pg/mL. Longitudinal data showed: final TCa p[0.00001, ICa p[0.00001, phosphorus p[0.0001, magnesium p=0.9, 24-h urinary calcium p=0.4, 25-hydroxycholecalciferol p=0.01, PTH p[0.00001. High circulating parathyrin values due to PHP normalized after surgery in addition to statistical significant changes of TCa, ICa, P, lumbar Bone Mineral Density provided by Dual-Energy X-Ray Absorptiometry; Mg and 24-h Ca might not be a marker of general mineral metabolism improvement.

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