in this work a glass micromodel which its grains and pores are non-uniform in size, shape and distribution is considered as porous medium. a two-dimensional random network model of micromodel with non-uniform pores has been constructed. the non-uniformity of porous model is achieved by assigning parametric distribution functions to pores throat and pores length, which was measured using image a...

without doubt is one important aspects of sustainable forest management the continuing forest regeneration. identify and determine is effective dispersal and distribution pattern of regeneration patches in various types of forest and its evolution, in maintaining biodiversity in natural ecosystems. purpose was chosen of gorazbon district kheyrod forest for study, all patches regeneration were l...

An increase in the distribution of data points indicates the presence of genetic or environmental modifiers. Mapping of the genetic control of the spread of points, the uniformity, allows us to allocate genetic difference in point distribution to adjacent, cis effects or to independently segregating, trans genetic effects. Our genetic architecture-mapping experiment elucidated the "environmenta...

The RF B(1) distribution was studied, theoretically and experimentally, in phantoms and in the head of volunteers using a 3 T MRI system equipped with a birdcage coil. Agreement between numerical simulation and experiment demonstrates that B(1) distortion at high field can be explained with 3D full-Maxwell calculations. It was found that the B(1) distribution in the transverse plane is strongly...

Sub-100-nm nanoparticles were prepared from beta-lactoglobulin (BLG) with a narrow size distribution by a desolvation method using glutaraldehyde for cross-linking. With pre-heating of the BLG solution to 60 degrees C and subsequent pH readjustment to 9.0, nanoparticles of 59 +/- 5 nm were obtained with improved uniformity. Bovine serum albumin (BSA) nanoparticles, prepared under similar condit...

Environ. Entomol. 13: 1191-1200 (1984) ABSTRACT The attack sites of the bark beetle, I. typographus, on Norway spruce logs were observed to be more uniformly spaced than random using nearest neighbor analysis. A computer model which simulated various degrees of uniformity in spatial distribution was compared to the observed attack pattern. The model showed that a mechanism of spacing between at...

In this work a glass micromodel which its grains and pores are non-uniform in size, shape and distribution is considered as porous medium. A two-dimensional random network model of micromodel with non-uniform pores has been constructed. The non-uniformity of porous model is achieved by assigning parametric distribution functions to pores throat and pores length, which was measured using ima...

The overall thermal performance of a Parabolic Trough Collector (PTC) depends on its optical performance, particularly the uniformity of the irradiance distribution and the resultant optical efficiency of the collector. Local Concentration Ratio (LCR), optical efficiency and average light concentration are three fundamental parameters of the optical performance of a PTC. These parameters are af...

Purpose: The purpose of the current work was experimental investigations of the mean breast dose and volume dose distributions with and without adaptive filtration. Adaptive filtration of the x-ray beam is used in dedicated breast CT to reduce dynamic range requirements on the detector, and to improve image quality. The adaptive filter has a predetermined shape, it is placed after the x-ray sou...