Search results for "VOLUME"

A Lagrangian method for deriving new indefinite integrals of special functions

2015

A new method is presented for obtaining indefinite integrals of common special functions. The approach is based on a Lagrangian formulation of the general homogeneous linear ordinary differential equation of second order. A general integral is derived which involves an arbitrary function, and therefore yields an infinite number of indefinite integrals for any special function which obeys such a differential equation. Techniques are presented to obtain the more interesting integrals generated by such an approach, and many integrals, both previously known and completely new are derived using the method. Sample results are given for Bessel functions, Airy functions, Legendre functions and hype…

An affordable method to obtain cultured endothelial cells from peripheral blood

2013

The culture of endothelial progenitor cells (EPC) provides an excellent tool to research on EPC biology and vascular regeneration and vasculogenesis. The use of different protocols to obtain EPC cultures makes it difficult to obtain comparable results in different groups. This work offers a systematic comparison of the main variables of most commonly used protocols for EPC isolation, culture and functional evaluation. Peripheral blood samples from healthy individuals were recovered and mononuclear cells were cultured. Different recovery and culture conditions were tested: blood volume, blood anticoagulant, coating matrix and percentage of foetal bovine serum (FBS) in culture media. The succ…

Does Optimal Volume Fraction in Percutaneous Vertebroplasty Prevent Cement Leakage?

2018

Centrifuge tests on strip footings on sand with a weak layer

2017

Tests on small-scale physical models of a strip footing resting on a dense sand bed containing a thin horizontal weak soil layer were carried out at normal gravity (1 g ). The results, reported in a companion paper, point out that the weak layer plays an important role in the failure mechanism and the ultimate bearing capacity of the footing if it falls within the ground volume relevant to the behaviour of the sand–footing system. The same problem was also investigated by means of centrifuge tests on reduced-scale models at 25 g and 40 g . The results of these tests, reported and discussed in this paper, confirm that failure mechanisms are governed substantially by the presence of the weak…

Evolution of Free Volumes in Polycrystalline BaGa2O4 Ceramics Doped with Eu3+ Ions

2021

H.K. and Y.K. would like to thank A. Ingram for assistance in PAL experiments. The authors thank E.A. Kotomin and M. Brik for the many useful discussions. The research was (partly) performed in the Institute of Solid State Physics, University of Latvia ISSP UL. ISSP UL as the Center of Excellence is supported through the Framework Program for European universities Union Horizon 2020, H2020-WIDESPREAD-01–2016–2017-TeamingPhase2 under Grant Agreement No. 739508, CAMART2 project.

Positron Annihilation in IR Transmitting GeS₂-Ga₂S₃ Glasses

2015

Positron annihilation lifetime spectroscopy combined with Doppler broadening of annihilation radiation was applied to study free-volume entities in GeS2-Ga2S3 glasses affected by Ga additions. It is shown that Ga-related void sub-system plays a decisive role in positron trapping process, while the overall density variation is defined mainly by Ge-related sub-system. These results serve as basis for new characterization route for inner free-volume structure of these glasses.

Mathematical modelling of physical phenomena

1996

The word “physics” is derived from the Greek “fysis” which means nature. Physics investigates fundamental natural phenomena and thus physical knowledge has a very general character. This is also the reason why physics penetrates other areas including electrical engineering.

Diffusion of Oxygen through Cork Stopper: Is It a Knudsen or a Fickian Mechanism?

2014

International audience; The aim of this work is to identify which law governs oxygen transfer through cork: Knudsen or Fickian mechanism. This is important to better understand wine oxidation during post-bottling aging. Oxygen transfer through cork wafers is measured at 298 K using a manometric permeation technique. Depending on the mechanism, we can extract the transport coefficients. Increasing the initial pressure of oxygen from 50 to 800 hPa leads to a change in the values of the transport coefficients. This implies that oxygen transport through cork does not obey the Knudsen law. From these results, we conclude that the limiting step of oxygen transport through cork occurs in the cell …

Evidence for a surface self-cleaning sputtering mechanism in fast atom bombardment mass spectrometry

1985

Evidence for a surface self-cleaning sputtering mechanism in fast atom bombardment mass spectrometry involving significant sputtering from the bulk of the glycerol matrix has been obtained from (a) the time dependence of sample ion abundances and chemical noise for bioorganic compounds, (b) determinations of the sputtering volume in glycerol solution, and (c) studies of in situ chemical and biochemical reactions. The relevance of these results for optimal sample/matrix preparation in analytical applications is pointed out.

Simple variable-volume injector for flow-injection systems

1990

Abstract A simple and versatile variable-volume injector is described for the introduction of samples in flow-injection systems. The device delivers precisely and reproducibly (usually r.s.d.