BACKGROUND AND AIMS There is no consensus about the effect of tongue thrusting on incisor position. The purpose of this study was to evaluate the position of anterior teeth in growing children with tongue thrust swallowing. MATERIALS AND METHODS In the present study 193 subjects with an age range of 9 to 13 years participated. All the patients were examined by a trained investigator and those...

As pulse detonation engine development matures, it becomes increasingly important to consider how practical details such as the implementation of valves and nozzles will affect performance. Inlet valve timing and valveless inlet designs may result in flow of products back upstream and, consequently, reduction in impulse over the ideal case. Although proper inlet design or operation under flowin...

This paper presents the design, development and characterization of contractile water jet thruster (CWJT) for mini underwater robot. Instead of electric motor, this CWJT utilizes the Ionic Polymer Metal Composite (IPMC) as the actuator to generate the water jet. The main focus of this paper is to analyze the conceptual design of the proposed CWJT which would determine the thrust force value, je...

A sub-micronewton level thrust stand is used to evaluate the performance of five different microthrusters. Using a torsional balance design, the JPL microthrust stand (μTS) is capable of measuring steady-state thrust as low as 1 μN with sub-micronewton resolution and an impulse as low as 1 μNs with sub-micronewton-second resolution. The μTS can support a test object with a mass as large as 10 k...

The problem of minimum-fuel, time-fixed, low-thrust rendezvous is addressed with the particular aim of developing a solver to determine optimal low-thrust Peer-to-Peer (P2P) maneuvers, which will be an integral part of distributed lowthrust servicing missions for multiple satellites. We develop the solver based on an indirect optimization technique and utilize the well-known shooting method to ...

The effect of fuel to oxidiser ratio on the thrust performance of a novel CubeSat propulsion system is presented in this paper. This propulsion system uses aluminium wool as fuel and a mixture of water and sodium hydroxide as oxidiser. The goal of the experiment is to determine the effect of fuel to oxidiser ratio on the thrust profile of the device, as measured with a pendulum type thrust bala...

The first Dynamic Positioning (DP) systems emerged in the 1960’s from the need for deep water drilling by the offshore oil and gas industry, as conventional mooring systems, like a jack-up barge or an anchored rig, can only be used in shallow waters. GustoMSC has been developing DP drill ships since the early 1970’s and it is still one of their core businesses. DP systems automatically control ...

Vertical turbine pumps are designed to operate with the pump shafts in tension (downthrust). Most pump and motor manufacturers caution users to not operate the vertical turbine pumps at conditions that result in “upthrust.” Upthrust conditions are usually encountered for a few seconds each time the pump is started; however, the pump should not be operated for periods longer than a few seconds i...

In this paper a nonlinear thrust controller for fixed pitch marine propellers with torque loss estimation and an antispin strategy is presented. The controller, designed to operate in the four-quadrant plane composed by the shaft speed and the vessel speed, is a combination of a thrust controller developed for calm/moderate sea states and an anti-spin strategy to reduce power peaks and wear-and...