The effects of link annotations on user search performance in hypertext environments having deep (layered) and shallow link structures were investigated in this study. Four environments were tested—layered-annotated, layered-unannotated, shallow-annotated, and shallow-unannotated. A single document was divided into 48 sections, and layered and unlayered versions were created. Additional version...

Background: It has recently been shown that the particle size of materials used for radiation shielding can affect the magnitude of radiation attenuation. Over the past years, application of nano-structured materials in radiation shielding has attracted attention world-wide. The purpose of this study was to investigate the shielding properties of the lead-free shields containing micro and nano-...

Introduction: This study introduces a novel polyvinyl chloride (PVC)/tungsten composites with characterization of their shielding properties by employing different techniques. Methods: The PVC/tungsten composites were produced by employing various weight fractions of tungsten micro-particles including 0, 20, and 40 % wt via melt blending method. In the next st...

conclusions available shields for the thyroid and eyes should be implemented in clinical practice. further research is needed to demonstrate the prevalence of shielding in the clinical setting. results only a limited number of studies have been performed on the use of shields for the eyes and thyroid, but the evidence shows an overall benefit to their use. this study demonstrates how thyroid sh...

background: polyethylene composites including boron can be used as an effective neutron shield. our investigation focuses on manufacturing borated polyethylene nano-composite. the purpose of this study is to design a radiation shield for use in both neutron and gamma fields. materials and methods: borated polyethylene shields containing 2%, and 5% weight percentage of boron nano-particles were ...

background: it has recently been shown that the particle size of materials used for radiation shielding can affect the magnitude of radiation attenuation. over the past years, application of nano-structured materials in radiation shielding has attracted attention world-wide. the purpose of this study was to investigate the shielding properties of the lead-free shields containing micro and nano-...

Given an uncountable regular cardinal κ, a partial order is κstationarily layered if the collection of regular suborders of P of cardinality less than κ is stationary in Pκ(P). We show that weak compactness can be characterized by this property of partial orders by proving that an uncountable regular cardinal κ is weakly compact if and only if every partial order satisfying the κ-chain conditio...

this paper investigates the lateral vibration of single-layered graphene sheets based on a new theory called doublet mechanics with a length scale parameter. after a brief reviewing of doublet mechanics fundamentals, a sixth order partial differential equation that governs the lateral vibration of single-layered graphene sheets is derived. using doublet mechanics, the relation between natural f...