Partial differentiation of air density in mass metrology

Vacuum Technology Considerations For Mass Metrology

Vacuum weighing of mass artifacts eliminates the necessity of air buoyancy correction and its contribution to the measurement uncertainty. Vacuum weighing is also an important process in the experiments currently underway for the redefinition of the SI mass unit, the kilogram. Creating the optimum vacuum environment for mass metrology requires careful design and selection of construction materi...

Thermal Desorption Mass Spectrometry (tds) Application on Mass Metrology

A new device has been developed for the study of physisorbed elements on polished and large surface used in mass metrology. This technique, based on the analysis by mass spectrometry of desorbed molecules caused by heating under vacuum from the analyzed surface, is presented. The first application of this device is the study of the current and future mass standards to understand the reactivity ...

Differentiation of benign and malignant breast lesions by apparent diffusion coefficient value in mass and non-mass lesions

Background: Diffusion-weighted imaging (DWI) is one of methods in evaluation of breast lesions. We aimed to investigate the apparent diffusion coefficient (ADC) values in breast tumors and their accuracy in differentiating benign versus malignant lesions. Methods: In this cross-sectional study, 72 patients with 88 breast lesions were investigated by 1.5-T breast MRI from 2015 to 2017 in Athari...

Evaluation of bone mass density in healthy individuals in Ahvaz (2000-2003)

Background: Osteoporosis is one of the most common problems in the women, especially after menopause and at the old age. Bone densitometry of vertebrae of lumbar region and femoral neck is a non invasive and precise method for evaluation of bone mass density (BMD) and determination of fracture risk. Materials and Method: from different districts of Ahvaz city, more than 300 healthy men and wo...

Numerical Study of Non - Equilibrium Air Dissociation For Calculation of Electron Density in Hypersonic Flow