3,535 research outputs found
Reduced 30% scanning time 3D multiplexer integrated circuit applied to large array format 20KHZ frequency inkjet print heads
Enhancement of the number and array density of nozzles within an inkjet head
chip is one of the keys to raise the printing speed and printing resolutions.
However, traditional 2D architecture of driving circuits can not meet the
requirement for high scanning speed and low data accessing points when nozzle
numbers greater than 1000. This paper proposes a novel architecture of
high-selection-speed three-dimensional data registration for inkjet
applications. With the configuration of three-dimensional data registration,
the number of data accessing points as well as the scanning lines can be
greatly reduced for large array inkjet printheads with nozzles numbering more
than 1000. This IC (Integrated Circuit) architecture involves three-dimensional
multiplexing with the provision of a gating transistor for each ink firing
resistor, where ink firing resistors are triggered only by the selection of
their associated gating transistors. Three signals: selection (S), address (A),
and power supply (P), are employed together to activate a nozzle for droplet
ejection. The smart printhead controller has been designed by a 0.35 um CMOS
process with a total circuit area, 2500 x 500 microm2, which is 80% of the
cirucuit area by 2D configuration for 1000 nozzles. Experiment results
demonstrate the functionality of the fabricated IC in operation, signal
transmission and a potential to control more than 1000 nozzles with only 31
data access points and reduced 30% scanning time.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/EDA-Publishing
Variable Powder Flow Rate Control in Laser Metal Deposition Processes
This paper proposes a novel technique, called Variable Powder Flow Rate Control (VPFRC), for
the regulation of powder flow rate in laser metal deposition processes. The idea of VPFRC is to
adjust the powder flow rate to maintain a uniform powder deposition per unit length even when
disturbances occur (e.g., the motion system accelerates and decelerates). Dynamic models of the
powder delivery system motor and the powder transport system (i.e., five–meter pipe, powder
dispenser, and cladding head) are first constructed. A general tracking controller is then designed
to track variable powder flow rate references. Since the powder flow rate at the nozzle exit
cannot be directly measured, it is estimated using the powder transport system model. The input
to this model is the DC motor rotation speed, which is estimated on–line using a Kalman filter.
Experiments are conducted to examine the performance of the proposed control methodology.
The experimental results demonstrate that VPFRC is successful in maintaining a uniform track
morphology, even when the motion control system accelerates and decelerates.Mechanical Engineerin
Three dimensional viscous analysis of a hypersonic inlet
The flow fields in supersonic/hypersonic inlets are currently being studied at NASA Lewis Research Center using 2- and 3-D full Navier-Stokes and Parabolized Navier-Stokes solvers. These tools have been used to analyze the flow through the McDonnell Douglas Option 2 inlet which has been tested at Calspan in support of the National Aerospace Plane Program. Comparisons between the computational and experimental results are presented. These comparisons lead to better overall understanding of the complex flows present in this class of inlets. The aspects of the flow field emphasized in this work are the 3-D effects, the transition from laminar to turbulent flow, and the strong nonuniformities generated within the inlet
Sputum biomarkers and the prediction of clinical outcomes in patients with cystic fibrosis
pre-printLung function, acute pulmonary exacerbations (APE), and weight are the best clinical predictors of survival in cystic fibrosis (CF); however, underlying mechanisms are incompletely understood. Biomarkers of current disease state predictive of future outcomes might identify mechanisms and provide treatment targets, trial endpoints and objective clinical monitoring tools. Such CF-specific biomarkers have previously been elusive. Using observational and validation cohorts comprising 97 nontransplanted consecutively-recruited adult CF patients at the Intermountain Adult CF Center, University of Utah, we identified biomarkers informative of current disease and predictive of future clinical outcomes. Patients represented the majority of sputum producers. They were recruited March 2004-April 2007 and followed through May 2011. Sputum biomarker concentrations were measured and clinical outcomes meticulously recorded for a median 5.9 (interquartile range 5.0 to 6.6) years to study associations between biomarkers and future APE and time-to-lung transplantation or death. After multivariate modeling, only high mobility group box-1 protein (HMGB-1, mean = 5.84 [log ng/ml], standard deviation [SD] = 1.75) predicted time-to-first APE (hazard ratio [HR] per log-unit HMGB-1 = 1.56, p-value = 0.005), number of future APE within 5 years (0.338 APE per log-unit HMGB-1, p,0.001 by quasi-Poisson regression) and time-to-lung transplantation or death (HR = 1.59, p = 0.02). At APE onset, sputum granulocyte macrophage colony stimulating factor (GM-CSF, mean 4.8 [log pg/ml], SD = 1.26) was significantly associated with APE-associated declines in lung function (210.8 FEV1% points per logunit GM-CSF, p,0.001 by linear regression). Evaluation of validation cohorts produced similar results that passed tests of mutual consistency. In CF sputum, high HMGB-1 predicts incidence and recurrence of APE and survival, plausibly because it mediates long-term airway inflammation. High APE-associated GM-CSF identifies patients with large acute declines in FEV1%, possibly providing a laboratory-based objective decision-support tool for determination of an APE diagnosis. These biomarkers are potential CF reporting tools and treatment targets for slowing long-term progression and reducing short-term severity
Numerical Calculations of Shock-Wave/Boundary-Layer Flow Interactions
The paper presents results of calculations for 2-D supersonic turbulent compression corner flows. The results seem to indicate that the newer, improved kappa-epsilon models offer limited advantages over the standard kappa-epsilon model in predicting the shock-wave/boundary-layer flows in the 2-D compression corner over a wide range of corner angles and flow conditions
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