5,630 research outputs found
Recommended from our members
Dependence of Drop Speed on Nozzle Diameter, Viscosity and Drive Amplitude in Drop-on-Demand Ink-Jet Printing
Get PDFResults of recent experiments and numerical simulations are presented, which have been used to establish empirical rules for
the dependence of drop speed on nozzle diameter and drive amplitude for Newtonian and non-Newtonian fluids printed with a
range of different ink-jet print-head technologies. Experiments were carried out with Xaar, MicroFab and Spectra Dimatix print heads and with solutions of polystyrene in diethyl phthalate as model fluids. These results are compared with
predictions from recent numerical codes developed by collaborators in the University of Leeds, and from simple models for drop-on-demand fluid jetting resulting from physical law
Recommended from our members
Jetting, In-Nozzle Meniscus Motion and Nozzle-Plate Flooding in An Industrial Drop-on-Demand Print Head
Get PDFThe state of the ink film at and near the nozzles of a drop-ondemand(DoD) print head during jetting has a direct impact on
printing performance and reliability. We have developed highspeed imaging apparatus and analytical techniques to investigate
the ink film dynamics on an industrial print head nozzle-plate in real-time. In addition to a direct correlation between the jet
emergence velocity and drive voltage, drive-dependent variations in the oscillation of the ink meniscus in adjacent nozzles were also observed. Using a ray-tracing model to analyze the meniscus shape, the meniscus oscillations for both printing and nonprinting nozzles were found to be complex and involve elements such as pre-oscillation and high-order surface waves. The flooding of non-firing nozzles, deliberately caused by the application of maximum drive voltage to a neighboring nozzle, has been recorded and analyzed dynamically. The build-up of fluid in an annulus around the nozzle (flooding rate) has been characterized and compared with models for the net ink flow
through the nozzle
Recommended from our members
Holographic Measurement of Drop-on-Demand Drops in Flight
Get PDFThe analysis of images of ink drops in flight can provide information about jet straightness, drop velocity and volume.
However trade-offs between field of view, optical and digital resolution and other factors such as depth of field and optical
distortion, limit the accuracy and amount of information available from a single image. In-line, digital holograms of drops in flight
can capture information from fields of view at least as large as the area of the digital sensor. Using mathematical reconstruction
techniques particularly suited to sparse, small objects of regular geometry the accuracy of measurement can potentially be submicrometer on drop position and diameter.
This paper describes our experimental apparatus, hologram reconstruction techniques and the results of experiments on
imaging drops. We also discuss techniques to improve the accuracy of the technique in the direction of the optical axis
Object drop in L3 acquisition
No full textThe topic of cross-linguistic differences regarding the overt or null expression of arguments has been considered both in first (L1) and second language (L2) acquisition. There is abundant literature on both subject and object drop with different language pairings but the issue has not been considered in third language (L3) acquisition. The main goal of this article is to analyse the L3 interlanguage of Basque-Spanish bilinguals regarding the acceptability and interpretation of null objects. The three languages involved in the study display different semantic requirements for the target structure, with Basque allowing for a null object option across-the-board, Spanish only under certain semantic conditions, and English disallowing it in the standard variety. Two trilingual, one bilingual and a control group (n = 119) rated experimental items embedded in context, presented in a written and aural format on a computer screen. Findings point to the successful acquisition of the target structure, as well as a clear influence of Spanish in the three experimental groups
Experimental investigation on Marangoni drop rations using drop shaft facility
Get PDFExperimental hardware has been developed to perform the experiments of drop Marangoni migration in the case of intermediate Reynolds numbers ina microgravity environment. The experiments were completed using the drop shaft free fall facility with a 4.5 s microgravity period in the Microgravity Laboratory of Japan. A special experimental method was designed for experimenting with a short microgravity period. In this experiment, the thermocapillary velocity of drop migration, driven only by the thermocapillary effect, was obtained. Experimental results show that Marangoni migration velocity depends on the temperature gradient and the drop diameter For fixed experimental mediums; the thermocapillary velocity of this present experiment is obviously smaller than the one suggested by YGB linear theory. This conclusion agrees, in general, with that of the ground-based experiment
Pressure drop and turbulence statistics in transpired pipe flow
No full textMeasurements of turbulent flow in a horizontal pipe subjected to wall transpiration are presented. Results include data on global flow rates and pressure drop, and local mean and fluctuating velocity profiles. Two distinct flow transpiration rates are studied, = / = 0.0005 and 0.001. The effects of flow transpiration on the friction-coefficient are compared with theoretical predictions. The theory furnishes predictions accurate to 3\%
Isolation of a somatomedin binding protein from human preterm amniotic fluid : development of a radioimmunoassay
Get PDFThis thesis study was undertaken in order to investigate
the nature and biological behavior of a somatornedin
binding protein, identified in preterrn amniotic fluid (AF).
Somatomedin (SM) is the generic designation applied to
a family of serum peptide growth factors which are growth
hormone dependent, stimulate incorporation of sulphate
into cartilage, have insulin-like actions on nonskeletal
tissues and increase mitosis in a wide variety of cultured
cells. Thusfar two peptides have been fully characterized:
insulin-like growth factor I (IGF-I), shown to be identical
to sornatomedin-C, and insulin-like growth factor II
(IGF-II). IGF-I and IGF-II have a 62% aminoacid sequence
identity and are 38-48% homologous with the A and B domains
of human pro-insulin
- …
