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...

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...

Patterned surfaces have proven to be a valuable design enhance adhesion, increasing hysteresis and the detachment stress at pull-off. To obtain high adhesive performance, soft materials are commonly, used, which easily conform countersurface, such as polymers elastomers. Such viscoelastic; i.e., they show rate-dependent properties. Here, of two half spaces is studied, one being flat other havin...

introduction in this study, we have investigated the effect of using phosphoric acid on bonding efficacy of an all-in-one adhesive system, after salivary contamination of dentin. methods and materials eighty-four extracted human molars were prepared for their superficial dentins to be exposed. the molars separated into 7 groups. group 1 specimens were not contaminated. in groups 2-4, samples we...

abstract statement of problem: the viscosity of orthodontics adhesive primers is crucial for stability and correct brackets ‘position during bond up. an excessive adhesive flow during brackets seating could change the brackets’ position. objectives: the main purpose of this study was to investigate the viscosity of four orthodontic adhesive primers in two different temperatures. materials and m...

introduction: the aim of this study was to compare the microleakage of beneath the orthodontic brackets bonded with 3 different bonding techniques and evaluate the effect of thermocycling. methods: one hundred and twenty premolars were randomly divided into 6 groups, received the following treatment: group 1: 37% phosphoric acid gel+unite primer+unite adhesive, group 2: 37% phosphoric acid gel+...

the effect of temperature on the viscoelastic behavior of chicken meat frankfurters was assessed by creep recovery tests. compression creep-recovery tests were performed at room temperature (20°c) and refrigeration (5°c) on samples of cylindrical shape. the viscoelastic behavior of samples was characterized based on the parameters of the four-element burgers model. during the compression phase,...

Mucosa-adhesive gels can be used as a useful mean of delivering drugs to or via mucosal membranes, and in particular buccal mucosa. Carbomers are among the best mucosa-adhesive materials known. The aim of this study was to compare the results obtained from the mucosa-adhesive strength of aqueous gels containing Carbomers, either alone or in combination, to the data obtained from assessing the d...