needle insertion is a minimally invasive technique in diagnosing and treating tumors. however, to perform a surgery accurately, the tissue should have minimum amount of displacement during needle insertion so that it reaches the target tissue. therefore, the tissue membrane has to move less to decrease rupturing under the membrane. in this study, the effect of different design parameters on dis...

In this paper, we show how fractional viscoelastic models can be efficient in the modeling of linear viscoelastic behavior, increasing the fitting accuracy of classic generalized viscoelastic models, such as the Generalized Maxwell model. Experimental data (Loss and Storage modulus in the frequency domain) were retrieved from a Dynamic Mechanical Analysis test considering Carbon Fibre Reinforce...

The spinning of polymeric fibers, the processing of numerous foodstuffs and the peel & tack characteristics of adhesives is associated with the formation, stability and, ultimately, the longevity of thin fluid ‘strands’. This tendency to form strands is usually described in terms of the tackiness of the fluid or by heuristic concepts such as ‘stringiness’ [Lakrout et al., J. Adhesion 69, 307 (1...

the effect of four types of shortening including a commercially vegetable oil (as control), palm olein (po), palm stearin (ps), and a blend of the latter two oils with rapeseed oil (bf) on the rheological properties of cookie dough was determined by using dynamic oscillatory measurement testing. all of the obtained dough treatments showed weak liquid viscoelastic behavior. their storage (g ) an...

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+...

In health, the airways are lined by a layer of protective mucus gel that sits atop a watery periciliary fluid. Mucus is an adhesive, viscoelastic gel, the biophysical properties of which are largely determined by entanglements of long polymeric gel-forming mucins, MUC5AC and MUC5B. This layer entraps and clears bacteria and inhibits bacterial growth and biofilm formation. It also protects the a...

AIMS AND OBJECTIVES The aim of this study is to compare whether differences exist between 2 viscoelastic foam support surfaces in the development of new pressure ulcers. BACKGROUND There is evidence to support the use of viscoelastic foam over standard hospital foam to reduce pressure. A comparative effectiveness study was done to compare 2 viscoelastic foam support surfaces. DESIGN A rando...

We solve the free boundary problem for the dynamics of a cylindrical, axisymmetric viscoelastic filament stretching in a gravity-driven extensional flow for the Upper Convected Maxwell and Oldroyd-B constitutive models. Assuming the axial stress in the filament has a spatial dependence provides the simplest coupling of viscoelastic effects to the motion of the filament, and yields a closed syst...

The problem of transient propagation in a homogeneous linear viscoelastic solid is investigated by means of the wave splitting technique. Two mechanical viscoelastic models are considered in particular, corresponding respectively to a single Maxwell element and to the series of a Maxwell element plus a Kelvin element. Analytical solutions for the split field are evaluated in terms of the wave p...

An instrumented indentation method is developed for generating maps of time-dependent viscoelastic and time-independent plastic properties of polymeric materials. The method is based on a pyramidal indentation model consisting of two quadratic viscoelastic Kelvin-like elements and a quadratic plastic element in series. Closed-form solutions for indentation displacement under constant load and c...