An electrospray thruster designed for nanosatellites is introduced in this paper. The has a compact size featuring passive propellant transport method through the use of porous materials. Porous emitters with 1, 25, and 100 emission tips were fabricated using conventional machining techniques. geometrical features measured high-precision laser profilometer. Thruster prototypes fitted different tested bipolar operation mode. currents voltage characteristics studied, which demonstrated wide...

The aim of this paper was to quantify the analysis error introduced by iterative closest point (ICP) image registration. We also investigated whether a subsequent subtraction process can reduce error.

To develop robust microelectromechanical systems (MEMS) switching technology for low voltage direct current (DC) applications (1–12 V) there is a requirement the investigation of wear caused by hot (contact operated while carrying load). Previous contact in ohmic MEMS switch has been limited to either completion cycles, where device destructively opened, or rates, making lifetime testing impractical. A novel platform described that capable both resolving microscale changes on surface between...

Enhanced switching performance during the interruption process is achieved when arc quickly enters and stays within splitter plate region with itself remaining attached to surface of plates. It well known that vent design in low-voltage devices (LVSDs) has a significant influence on motion an event: however, there been limited experimental studies correlating whole quenching chamber, including plates region, size distribution apertures, which are important for plasma flow LVSDs. This paper...

The influence of circuit parameters on an Ohmic (metal-metal contact) MEMS (microelectromechanical system) switch contact pair are investigated under hot-switching (carrying current) conditions below the arcing-threshold. A novel relay testing platform is used to investigate microscale surface change between individual switching events. materials a composite material vertically-aligned carbon-nanotubes with metallic (Au) layer, paired Au-coated ball contact. evolution evaluated along energy...

The electrical contacts in metal-metal MEMS switches are normally made from thin (<; 1 μm) metallic film, e.g. (Au). low contact force a device results small area for conduction; to increase the area, composite material has been developed. Sputter coated Au, applied vertically-aligned multi-walled carbon nanotubes, (Au-MWCNT composite), shown and extend switching lifetime by orders of magnitude. In this study Au-MWCNT is paired with Au hemisphere under 150 μN, an In-situ Contact Evolution...

Arc motion in a quenching chamber has significant influence on switching performance low voltage device (LVSD).A high-speed optical arc imaging system (AIS) been used to investigate the of design parameters motion.Arc light intensity is transmitted photodiodes AIS through fibres during process.The and associated software enable detailed be tracked inside at an image sampling rate 1 MHz.Since higher temperature leads greater radiation, it assumed that measured by related temperature.However,...

Abstract Natural human enamel (NHE) is a complex freeform surface which has presented significant difficulties in measuring form change using non-contacting laser profilometry (NCLP). Measuring on NHE metrology proxy for dental tooth structure loss, and characterising this non-ISO parameters (volume, area, normalised lesion depth) been seldom studied due complexity undetermined measurement errors. This study determines NCLP errors (instrument repeatability method reproducibility) parameters,...

A Ag/Ni electrical contact surface has been re-evaluated for volumetric erosion where a new improved method is developed to describe the wear distribution. The satisfies requirement that there near zero mass loss from anode and cathode combined surfaces low DC voltage current levels investigated, (14 V, 10.4 A).The material processed create highly structured designed reduce bounce. It shown bounce time reduced significantly. are measured using X-Ray CT conventional optical profiling....

Switching performance of a low-voltage switching device (LVSD) is determined by limiting current and stopping re-ignition. This strongly influenced how the arc moves inside LVSD quenching chamber during process. Improved achieved when quickly enters stays splitter plates LVSD, with attached to surface plates. article studies motion around in LVSDs correlation voltage. Arc investigated using high-speed optical imaging system (AIS). It observed that fluctuates as it plates, periods followed...

Most failures in micro electromechanical system (MEMS) switches can be attributed to the degradation of contact surfaces and sticking contacts. A wear-tolerant composite material, composed a Au film supported by multi walled carbon nanotubes (Au/MWCNT), has been engineered provide wear resistance enhanced switching lifetime with conductive properties close pure Au. Switching lifetimes billions cycles have demonstrated, representing greatly increased performance over thin Below arcing...

A metallic coated carbon nanotube surface, developed for use in a micro-electromechanical (MEMS) switching device, is investigated performance, when 4 VDC, with current levels between 10 to 600 mA; the objective of understanding upper limits surface performance. The used Gold Coated (500 nm), forest multi-walled nanotubes (50 μm), referred as Au/CNT. has been previously endurance at low μA, characterize cold performance over billion cycles and tested cantilever MEMs test system mA (hot...

This paper describes the results of an experiment to measure correlation between atmospheric turbulence induced intensity fluctuations in mid and long IR bands for transmission paths appropriate IRS&T. A DF laser operating at 3.8 microns a carbon-dioxide 9.24 served as sources. The experiments were conducted on 16 km path over Chesapeake Bay. Data was obtained under variety strengths including transition weak strong turbulence. experimental correlations values compared predictions model....

An overview is provided of the non-contact measurement surface morphology, focusing on form and roughness. Existing methods considered include con-focal scanning for evaluation large-scale surfaces where comparisons are drawn with direct areal measurements data stitching required to provide coverage large scale surfaces. The applications presented include, free dental metrology, paleontology early cylindrical mechanical sound recordings. Data registration determine low wear For new...

An automated in-situ contact evolution (ICE) apparatus is used to study performance for a low force (<1 mN) MEMS switching application. The ICE system uses metrology frame combine the controlled of surfaces with ability measure surface changes in-situ. After defined number cycles, are separated within and measured, then replaced same physical location precision 50 nm continue process. In this force, resistance relationship investigated evaluation effective resistivity dissimilar combination....