1,865 research outputs found
Development of Integration Software for Multiple Inkjet Functionalization Systems
Inkjet printing is widely used in functional product manufacturing. Performing a printing task requires communication and synchronization among multiple subsystems (e.g. motion and drop ejection), which introduces complexity in the overall printing system. A user interface has been developed, which enables users to input printing parameters and patterns for printing functional materials. The interface then sends commands to the controllers that execute the printing process. The software can also be expanded to carry out standard experiments for functional printing research and characterization. Moreover, the software is transferable to multiple systems. One application explored using the software is drug anti- counterfeiting research by printing edible coloring onto pills
Processing liquid metal for conformable electronics
Future generations of robots, electronics, and assistive medical devices will include systems that are soft, elastically deformable, and may adapt their functionality in unstructured environments. This will require soft active materials for power circuits and sensing of deformation and contact pressure. Liquid-embedded elastomer electronics offer one solution as key elements of highly deformable and soft robotic systems. Several designs for stretchable conductors and soft sensory skins (including strain, pressure, and curvature sensors) based on a liquid-embedded-elastomer approach have been developed. Many of these fluid–elastomer composites utilize liquid metal alloys due to their high conductivities and inherent compliance. Understanding how these alloys can be processed for high-yield manufacturability is critical to the development of parallel processing technology, which is needed to create more complex and low-cost systems. This discussion will highlight surface interactions between droplets of gallium–indium alloys and elastomeric substrates, and the implementation of this study to selective patterning, direct-writing, and inkjet printing of hyperelastic electronic components
MODELING AND EXPERIMENTAL VERIFICATION OF TORQUE RIPPLE IN PERMANENT MAGNET DC MOTORS
ABSTRACT In this paper we have developed a simple parametric model based on motor geometries to estimate the torque ripple in permanent-magnet DC (PMDC) motors. Torque ripple is the combined results of many different motor design parameters such as magnetic material properties and geometry as well as rotor slot geometry. As the PMDC motors are being used in more precision applications while being produced at a lower price, the effect of torque ripple is becoming an important issued for precision motion control. The main objective of this study is to identify motor parameters that affect the magnitude of the torque ripples as well as developing a cost effective measuring device for motor vendors. The analytical model focused on the effect of air gap volume on effective magnetic flux and in terms impact the torque generation. The effectiveness of the proposed model was verified by experimental data collected with motors from four large volume motor vendors that meets the same design specification. Sensitivity analysis was also performed to identify the key motor parameters that impacted the magnitude of the torque ripple. INTRODUCTION The use of brushed permanent magnet DC (PMDC) motors in machines that are used in precision application has become more common over the years. The reason for this trend is due to an increase in quality and cost effectiveness through advances in manufacturing processes. These advances have not however eliminated a periodic fluctuation of the output torque of the motor which is dependent on angular position and can be termed torque ripple (TR). This paper will first discuss a model of the motor developed torque T D and TR and then compar
Development and Evaluation of Low-Cost CO2 Sensors for Buildings
There is a significant opportunity to improve building energy efficiency and indoor environmental quality by accurately monitoring CO2 levels. However, current CO2 sensors tend to be expensive or require regular recalibration. This work presents research related to the initial development and evaluation of two novel CO2 sensors based on chemiresistive and resonant mass sensing techniques. Prototype sensors were assessed in a bench-top test chamber at temperatures, humidity levels, and CO2 concentrations, typical of indoor environments. Under these conditions, prototype sensors required only 60 mW of power, or less. Further, each sensor was developed to have a footprint of less than 25 mm2 and a cost of less than $50. Given the relative low cost, small size, and potential for low power consumption, these sensors may serve as an attractive alternative to the commercial CO2 sensors that are currently available
Mass Calibration and Cosmological Analysis of the SPT-SZ Galaxy Cluster Sample Using Velocity Dispersion and X-ray Measurements
We present a velocity dispersion-based mass calibration of the South Pole
Telescope Sunyaev-Zel'dovich effect survey (SPT-SZ) galaxy cluster sample.
Using a homogeneously selected sample of 100 cluster candidates from 720 deg2
of the survey along with 63 velocity dispersion () and 16 X-ray Yx
measurements of sample clusters, we simultaneously calibrate the
mass-observable relation and constrain cosmological parameters. The
calibrations using and Yx are consistent at the level,
with the calibration preferring ~16% higher masses. We use the full
cluster dataset to measure . The
SPT cluster abundance is lower than preferred by either the WMAP9 or
Planck+WMAP9 polarization (WP) data, but assuming the sum of the neutrino
masses is eV, we find the datasets to be consistent at the
1.0 level for WMAP9 and 1.5 for Planck+WP. Allowing for larger
further reconciles the results. When we combine the cluster and
Planck+WP datasets with BAO and SNIa, the preferred cluster masses are
higher than the Yx calibration and higher than the
calibration. Given the scale of these shifts (~44% and ~23% in mass,
respectively), we execute a goodness of fit test; it reveals no tension,
indicating that the best-fit model provides an adequate description of the
data. Using the multi-probe dataset, we measure and
. Within a CDM model we find eV. We present a consistency test of the cosmic growth rate.
Allowing both the growth index and the dark energy equation of state
parameter to vary, we find and ,
demonstrating that the expansion and the growth histories are consistent with a
LCDM model ().Comment: Accepted by ApJ (v2 is accepted version); 17 pages, 6 figure
Analysis of Sunyaev-Zel'dovich Effect Mass-Observable Relations using South Pole Telescope Observations of an X-ray Selected Sample of Low Mass Galaxy Clusters and Groups
(Abridged) We use 95, 150, and 220GHz observations from the SPT to examine
the SZE signatures of a sample of 46 X-ray selected groups and clusters drawn
from ~6 deg^2 of the XMM-BCS. These systems extend to redshift z=1.02, have
characteristic masses ~3x lower than clusters detected directly in the SPT data
and probe the SZE signal to the lowest X-ray luminosities (>10^42 erg s^-1)
yet.
We develop an analysis tool that combines the SZE information for the full
ensemble of X-ray-selected clusters. Using X-ray luminosity as a mass proxy, we
extract selection-bias corrected constraints on the SZE significance- and
Y_500-mass relations. The SZE significance- mass relation is in good agreement
with an extrapolation of the relation obtained from high mass clusters.
However, the fit to the Y_500-mass relation at low masses, while in good
agreement with the extrapolation from high mass SPT clusters, is in tension at
2.8 sigma with the constraints from the Planck sample. We examine the tension
with the Planck relation, discussing sample differences and biases that could
contribute.
We also present an analysis of the radio galaxy point source population in
this ensemble of X-ray selected systems. We find 18 of our systems have 843 MHz
SUMSS sources within 2 arcmin of the X-ray centre, and three of these are also
detected at significance >4 by SPT. Of these three, two are associated with the
group brightest cluster galaxies, and the third is likely an unassociated
quasar candidate. We examine the impact of these point sources on our SZE
scaling relation analyses and find no evidence of biases. We also examine the
impact of dusty galaxies using constraints from the 220 GHz data. The stacked
sample provides 2.8 significant evidence of dusty galaxy flux, which
would correspond to an average underestimate of the SPT Y_500 signal that is
(17+-9) per cent in this sample of low mass systems.Comment: 15 pages, 7 figure
- …