In this paper, natural frequencies and dynamic response of thick beams made of saturated porous materials resting on viscoelastic foundation are investigated for the first time. The beam is modeled using higher-order beam theory. Kelvin-voight model is used to model the viscoelastic foundation. Distribution of porosity along the thickness is considered in two different patterns, which are symme...

Therapy with exogenous surfactants is currently used for the treatment of respiratory distress syndrome of the newborn (RDS) and is under investigation for treatments related to adult RDS. However, the possible use of exogenous surfactant as a means of enhancing mucus clearance in other respiratory diseases has not been addressed. We therefore studied the effects of an artificial surfactant (Cu...

Both micro- and nanofluidics are finding increasing use in the growing toolbox of nanotechnology; for the production of nanoparticles, and as micro-reactors for carefully controlled chemical reactions. These laboratories-on-a-chip hold vast potential for industrial application, however, only the most simple are truly starting to emerge as commercially viable, particularly in the area of droplet...

The self-assembly of biological surfactants in water is an important topic for study because of its relevance to physiological processes. Two common types of biosurfactants are lecithin (phosphatidylcholine) and bile salts, which are both present in bile and involved in digestion. Previous studies on lecithin-bile salt mixtures have reported the formation of short, rodlike micelles. Here, we sh...

Abstraet--Surfactants are one of the major components (10-18%) of detergent and household cleaning products and are used in high volumes. Several are commonly found in natural waters and consequently, their impact on the environment has been, and continues to be, discussed in the U.S.A., Western Europe and Japan. The chronic and sublethal toxicities of commercially important surfactants to aqua...

in order to formulate an efficient and durable mucoadhesive drug delivery system, careful consideration of formulation-related parameters is critical. this study was conducted to investigate the effect of the presence of various types and concentrations of surfactants within or outside carbopol 934 (c934) as well as hydroxypropylmethyl cellulose (hpmc) solid compacts, on their duration of mucoa...

periodontal ligament is a thin layer of soft tissue that connects root of a tooth to the surrounding alveolar bone. these ligaments play an important role in initiating tooth movement when loads are applied to teeth with orthodontic appliances. the majority of such soft tissues exhibit as viscoelastic bodies or have a time-dependent behavior. due to the viscoelastic behavior of the periodontal ...

the purpose of this research is to numerically investigate the interaction of pulsatile flow of blood with an axisymmetric artery in various percentages of stenosis. the carreau non-newtonian model and the generalized maxwell rheological model were used to model the blood fluid and the viscoelastic wall of arterial, respectively. the innovation of the present research is modeling of viscoelasti...

Bearing a hydrophilic part and a hydrophobic part, surfactants can adsorb onto interfaces and lower the tension (γ) of the interfaces, thereby enhancing the interfacial properties and leading to the applications of surfactants in cleaning, surface functionalization, foaming and emulsification. To understand how they work in these applications it is important to know the time-scales of the surfa...

1,4-Dioxane impurity in nonionic surfactants and cosmetics were analyzed using solid-phase microextraction (SPME) coupled with gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Experimental results show that there is no significant difference using SPME-GC and SPME-GC-MS for analysis of 1,4-dioxane in three types of nonionic surfactants at the 95% confidence level. The r...