Measurement of the high rate flow properties of filled HDPE melts by capillary rheometer: Effects of the test geometry

2014 ◽  
Vol 37 ◽  
pp. 201-209 ◽  
Author(s):  
Francesco Baldi ◽  
Juri Ragnoli ◽  
Francesco Briatico-Vangosa
Keyword(s):  
High Rate ◽  
Capillary Rheometer ◽  
Flow Properties ◽  
Test Geometry

Rheological Properties of Cemented Tungsten Carbide Feedstock for Micro Powder Injection

2013 ◽  
Vol 773-774 ◽  
pp. 827-832
Author(s):  
Abdolali Fayyaz ◽  
Norhamidi Muhamad ◽  
Abu Bakar Sulong ◽  
Heng Shye Yunn ◽  
Sri Yulis M. Amin ◽  
...  
Keyword(s):  
Tungsten Carbide ◽  
Flow Behavior ◽  
Laser Diffraction ◽  
Powder Injection ◽  
Capillary Rheometer ◽  
Flow Properties ◽  
Low Viscosity ◽  
Highly Sensitive ◽  
Different Temperatures ◽  
Cemented Tungsten Carbide

The rheological behavior of feedstock needs to be examined for manufacturing parts without defects by micro powder injection molding (μPIM). In this study, submicron tungsten carbide (WC) and cobalt (Co) were milled for several hours. The distribution and morphology of the powder mixture were analyzed by laser diffraction and scanning electron microscopy. After measurement of critical powder loading, cemented tungsten carbide (WCCo) powder was mixed with a thermoplastic/paraffin wax binder with a powder loading volume from 50% to 52% to obtain feedstock. The flow properties of the WCCo feedstock were evaluated using a capillary rheometer at different temperatures. It was found that feedstock exhibit a pseudoplastic flow behavior, which is one of the main requirements for μPIM. Feedstock is also shown to be highly sensitive to temperature at high powder loading. Low powder loading led to low viscosity at a high shear rate that cannot be used in μPIM because it results in powder and binder separation.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

Rapid Freezing of Freeze-Etch Specimens

1980 ◽  
Vol 38 ◽  
pp. 752-755
Author(s):  
A. Elgsaeter ◽  
T. Espevik ◽  
G. Kopstad
Keyword(s):  
Low Temperature ◽  
Metal Surface ◽  
Relative Velocity ◽  
Thermal Contact ◽  
High Rate ◽  
Rapid Freezing ◽  
Temperature Decrease ◽  
Freeze Etching

The importance of a high rate of temperature decrease (“rapid freezing”) when freezing specimens for freeze-etching has long been recognized1. The two basic methods for achieving rapid freezing are: 1) dropping the specimen onto a metal surface at low temperature, 2) bringing the specimen instantaneously into thermal contact with a liquid at low temperature and subsequently maintaining a high relative velocity between the liquid and the specimen. Over the last couple of years the first method has received strong renewed interest, particularily as the result of a series of important studies by Heuser and coworkers 2,3. In this paper we will compare these two freezing methods theoretically and experimentally.

Physical and Hydrologic-Flow Properties of Fractures Las Vegas, Nevada—Zion Canyon, Utah—Grand Canyon, Arizona—Yucca Mountain, Nevada July 20–24, 1989

10.1029/ft385 ◽  
1989 ◽  
Author(s):  
Christopher C. Barton ◽  
Paul A. Hsieh ◽  
Jacques Angelier ◽  
Francoise Bergerat ◽  
Catherine Bouroz ◽  
...  
Keyword(s):  
Las Vegas ◽  
Grand Canyon ◽  
Yucca Mountain ◽  
Flow Properties

Why the high rate of dropout from individualized cognitive-behavior therapy for bulimia nervosa?

2001 ◽  
Author(s):  
Z. Steel ◽  
J. Jones ◽  
S Adcock ◽  
R Clancy ◽  
L. Bridgford-West ◽  
...  
Keyword(s):  
Bulimia Nervosa ◽  
Behavior Therapy ◽  
Cognitive Behavior Therapy ◽  
High Rate ◽  
Cognitive Behavior
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