OBJECTIVE To test the frictional resistance forces (FRS) generated between several archwires and (1) interactive self-ligating (ISL) brackets and (2) conventionally ligated (CL) brackets. MATERIALS AND METHODS Frictional forces produced between three different archwire combinations and self-ligating (SL) brackets (ceramic and metal-slot or all-metal) and CL brackets (metal or ceramic) were ev...

In this paper we define a class of mechanical systems consisting of rigid objects (defined by linear or quadratic surface patches) connected by frictional contact linkages between surfaces. (This class of mechanisms is similar to the Analytical Engine developed by Babbage in 1800s except that we assume frictional surfaces instead of toothed gears.) We prove that a universal Turing Machine (TM) ...

background: friction is usually encountered during sliding technique for orthodontic space closure. this study aims to investigate the effect of fluoride on frictional resistance between stainless steel orthodontic brackets and steel and niti arch wires. materials and methods: a total of 144 standard 022 stainless steel brackets were used in this experimental study. 0.016 and 0.019 × 0.025 inch...

INTRODUCTION The aim of this study was to evaluate the frictional resistance between active and passive self-ligating brackets and 0.019 × 0.025-in stainless steel archwire during sliding mechanics by using an orthodontic sliding simulation device. METHODS Maxillary right first premolar active self-ligating brackets In-Ovation R, In-Ovation C (both, GAC International, Bohemia, NY), and SPEED ...

The notion that business cycles are driven by demand shocks is subtle. I first review some of the conceptual and empirical challenges faced when trying to accommodate this notion in micro-founded, general-equilibrium models. I next review my own research, which sheds new light on the observed business cycles by accommodating frictional coordination in the form of higher-order uncertainty. This ...

This paper examines the time-consuming process of matching the two sides of a market each having diverse characteristics. This is cast in a labor market setting where workers of di®erent skills need be matched with di®erent machine qualities to produce output. I characterize the e±cient allocation and then show that it can be decentralized by a competitive framework. A prominent feature of the ...

We study the offers submitted by consumers to a large Name-Your-Own-Price (NYOP) online retailer. A distinctive feature of this retailer is that it allows consumers to repeatedly submit offers on one and the same product. While consumers could identify the threshold price (the minimum price for which the retailer is willing to sell) by incrementing their offer in small steps in each consecutive...

Introduction: During sliding mechanics, frictional resistance is an important counterforce to orthodontic tooth movement; which must be controlled to allow application of light continuous forces. objective: To investigate static and kinetic frictional resistance between three orthodontic brackets: ceramic, self-ligating, and stainless steel, and three 0.019×0.025” archwires: stainless steel, ni...

The objective of this investigation was to assess and compare the in vitro tribological behaviour of four commercially available self-ligating bracket systems. The frictional characteristics of the Damon3, Speed, In-Ovation R, and Time2 bracket systems were studied using a jig that mimics the three-dimensional movements that occur during sliding mechanics. Each bracket system was tested on the ...

Static and dynamic frictional phenomena at the interface with random impurities are investigated in a two-chain model with incommensurate structure. Static frictional force is caused by the impurity pinning and/or by the pinning due to the regular potential, which is responsible for the breaking of analyticity transition for impurity-free cases. It is confirmed that the static frictional force ...