A mathematical model for calculating contact mass loss resulting from bridge disintegration in vacuum

2011 ◽  
Vol 60 (4) ◽  
pp. 399-411
Author(s):  
Piotr Borkowski
Keyword(s):  
Mathematical Model ◽  
Mass Loss ◽  
Dynamic Changes ◽  
Contact Mass

A mathematical model for calculating contact mass loss resulting from bridge disintegration in vacuum The paper presents descriptions of bridge disintegration types and contact mass loss in the bridge stage. There is presented Matlab solvers to solve equation describing dynamic changes of temperature in the bridge region. The final result of program calculations is the mass loss and the volume of the metal of contacts which was lost during the bridge stage.

scholarly journals Modeling Drying of Degenerated Calluna vulgaris for Wildfire and Prescribed Burning Risk Assessment

Forests ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 759 ◽  
Author(s):  
Torgrim Log
Keyword(s):  
Mathematical Model ◽  
Numerical Model ◽  
Mass Loss ◽  
Diffusion Coefficients ◽  
Prescribed Burning ◽  
Fire Hazard ◽  
Fire Risk ◽  
Calluna Vulgaris ◽  
Fire Danger ◽  
Drying Process

Research highlights: Moisture diffusion coefficients for stems and branches of degenerated Calluna vulgaris L. have been obtained and a mathematical model for the drying process has been developed and validated as an input to future fire danger modeling. Background and objectives: In Norway, several recent wildland–urban interface (WUI) fires have been attributed to climate changes and accumulation of elevated live and dead biomass in degenerated Calluna stands due to changes in agricultural activities, i.e., in particular abandonment of prescribed burning for sheep grazing. Prescribed burning is now being reintroduced in these currently fire prone landscapes. While available wildfire danger rating models fail to predict the rapidly changing fire hazard in such heathlands, there is an increasing need for an adapted fire danger model. The present study aims at determining water diffusion coefficients and develops a numerical model for the drying process, paving the road for future fire danger forecasts and prediction of safe and efficient conditions for prescribed burning. Materials and methods: Test specimens (3–6 mm diameter) of dead Calluna stems and branches were rain wetted 48 h and subsequently placed in a climate chamber at 20 °C and 50% relative humidity for mass loss recordings during natural convection drying. Based on the diameter and recorded mass versus time, diffusion coefficients were obtained. A numerical model was developed and verified against recoded mass loss. Results: Diffusion coefficients were obtained in the range 1.66–10.4 × 10−11 m2/s. This is quite low and may be explained by the very hard Calluna “wood”. The large span may be explained by different growth conditions, insect attacks and a varying number of years of exposure to the elements after dying. The mathematical model described the drying process well for the specimens with known diffusion coefficient. Conclusions: The established range of diffusion coefficients and the developed model may likely be extended for forecasting moisture content of degenerated Calluna as a proxy for fire danger and/or conditions for efficient and safe prescribed burning. This may help mitigate the emerging fire risk associated with degenerated Calluna stands in a changing climate.

Analysis of Coal With Coal-Mule and Biomass Co-Combustion in Slurry Form/Analiza Współspalania Węgla Z Mułem Węglowym I Biomasą W Postaci Zawiesiny

2014 ◽  
Vol 59 (2) ◽  
pp. 347-366 ◽  
Author(s):  
Agnieszka Kijo-Kleczkowska
Keyword(s):  
Mathematical Model ◽  
Mass Loss ◽  
Fluidized Bed ◽  
Combustion Process ◽  
Environment Protection ◽  
Technical Application ◽  
Depth Analysis ◽  
Combustion Technology ◽  
The Mathematical Model

Abstract Combustion technology of coal-water fuels creates a number of new possibilities to organize the combustion process fulfilling contemporary requirements e. g in the environment protection. Therefore an in-depth analysis is necessary to examine the technical application of coal as energy fuel in the form of suspension. The paper undertakes the complex research of the coal with coal-mule and biomass co-combustion. The mathematical model enables the prognosis for change of the surface and the centre temperatures and a mass loss of the fuel during combustion in air and in the fluidized bed.

scholarly journals Identification of Statistical Patterns in the Field of Trademark Registration

2021 ◽  
pp. 53-62
Author(s):  
R.R. Vakilova ◽  
◽  
D.N. Verzilin ◽  
Keyword(s):  
Mathematical Model ◽  
Intellectual Property ◽  
Statistical Data ◽  
Dynamic Changes ◽  
Trademark Registration ◽  
Property Registration

The article is about identification of statistical patterns in the field of trademarks and service marksregistration. To identify patterns, official statistical data provided in the relevant state collections were used. The analysis of dynamic changes in the certificates and the filled applications allowed us to indicate positive conclusions about the intellectual property registration in Russia. The article also provided the hypothesis of the dependency between the number of organizations in a certain region and the number of registered trademarks and service marks. It was concluded that the hypothesis put forward about the presence of a possible dependence between the number of organizations in a certain region and the number of registered trademarks and service marks was partially confirmed. There really is a pattern, that is, with an increase in the number of organizations in a certain region, the number of registered trademarks and service marks increased, but it was not possible to build a clear mathematical model of dependence.

Ultrastructural Cytopiasmic Changes of Adrenal Cortex During Pregnancy

1969 ◽  
Vol 27 ◽  
pp. 298-299
Author(s):  
T. M. Murad ◽  
Karen Israel ◽  
Jack C. Geer
Keyword(s):  
Adrenal Gland ◽  
Steroid Hormones ◽  
Adrenal Cortex ◽  
Lipid Droplets ◽  
Plasma Cholesterol ◽  
Adrenal Steroids ◽  
Dynamic Changes ◽  
Cortical Cells ◽  
Acetyl Coenzyme A ◽  
Adrenal Cortical Cells

Adrenal steroids are normally synthesized from acetyl coenzyme A via cholesterol. Cholesterol is also shown to enter the adrenal gland and to be localized in the lipid droplets of the adrenal cortical cells. Both pregnenolone and progesterone act as intermediates in the conversion of cholesterol into steroid hormones. During pregnancy an increased level of plasma cholesterol is known to be associated with an increase of the adrenal corticoid and progesterone. The present study is designed to demonstrate whether the adrenal cortical cells show any dynamic changes during pregnancy.

Water accumulation as a function of temperature on specimens in an electron microscope cold stage

1986 ◽  
Vol 44 ◽  
pp. 114-115 ◽  
Author(s):  
M.K. Lamvik ◽  
D.A. Kopf ◽  
S.D. Davilla ◽  
J.D. Robertson
Keyword(s):  
Electron Microscope ◽  
Mass Loss ◽  
Liquid Helium ◽  
Liquid Nitrogen ◽  
Liquid Nitrogen Temperature ◽  
Liquid Helium Temperature ◽  
Helium Temperature ◽  
Cold Stage ◽  
Water Accumulation ◽  
Better Than

Last year we reported1 that there is a striking reduction in the rate of mass loss when a specimen is observed at liquid helium temperature. It is important to determine whether liquid helium temperature is significantly better than liquid nitrogen temperature. This requires a good understanding of mass loss effects in cold stages around 100K.

Electron Beam-Induced Mass Loss in Freeze-Dried Tissue and Protein Samples

1985 ◽  
Vol 43 ◽  
pp. 470-471
Author(s):  
M.E. Cantino ◽  
M.K. Goddard ◽  
L.E. Wilkinson ◽  
D.E. Johnson
Keyword(s):  
Electron Beam ◽  
Salivary Gland ◽  
Mass Loss ◽  
Counting Rate ◽  
Dose Dependence ◽  
X Ray ◽  
Large Samples ◽  
Freeze Dried ◽  
Muscle Homogenate ◽  
Large Muscle

Quantification in biological x-ray microanalysis depends on accurate evaluation of mass loss. Although several studies have addressed the problem of electron beam induced mass loss from organic samples (eg., 1,2). uncertainty persists as to the dose dependence, the extent of loss, the elemental constituents affected, and the variation in loss for different materials and tissues. in the work described here, we used x-ray counting rate changes to measure mass loss in albumin (used as a quantification standard), salivary gland, and muscle.In order to measure mass loss at low doses (10-4 coul/cm2 ) large samples were needed. While freeze-dried salivary gland sections of the required dimensions were available, muscle sections of this size were difficult to obtain. To simulate large muscle sections, frog or rat muscle homogenate was injected between formvar films which were then stretched over slot grids and freeze-dried. Albumin samples were prepared by a similar procedure. using a solution of bovine serum albumin in water. Samples were irradiated in the STEM mode of a JEOL 100C.

Sign in / Sign up

Export Citation Format

Share Document