A Model for Single-screw Plasticating Extruders

1989 ◽  
Vol 4 (4) ◽  
pp. 232-241 ◽  
Author(s):  
A. R. Vincelette ◽  
C. S. Guerrero ◽  
P. J. Carreau ◽  
P. G. Lafleur
Keyword(s):  
Single Screw

Malar Augmentation With Self-drilling Single-Screw Fixation

2000 ◽  
Vol 2 (3) ◽  
pp. 222-225 ◽  
Author(s):  
Neal D. Goldman ◽  
Ramsey Alsarraf ◽  
Gary Nishioka ◽  
Wayne F. Larrabee
Keyword(s):  
Screw Fixation ◽  
Single Screw

Modeling the Temperature Development of Wall-slipping Polymers in Single-screw Channels

2009 ◽  
Vol 24 (2) ◽  
pp. 106-113 ◽  
Author(s):  
M. Kurte-Jardin ◽  
H. Potente ◽  
K. Sigge ◽  
M. Bornemann
Keyword(s):  
Single Screw ◽  
Temperature Development

Single Versus Dual Headless Compression Screw Fixation of Scaphoid Nonunions: A Biomechanical Comparison

Hand ◽  
2021 ◽  
pp. 155894472097411
Author(s):  
Luke T. Nicholson ◽  
Kristen M. Sochol ◽  
Ali Azad ◽  
Ram Kiran Alluri ◽  
J. Ryan Hill ◽  
...  
Keyword(s):  
Screw Fixation ◽  
Qualitative Assessment ◽  
Secondary Outcome ◽  
Scaphoid Nonunion ◽  
Compression Screw ◽  
Single Screw ◽  
Headless Compression Screw ◽  
Significant Difference ◽  
Load To Failure ◽  
Headless Compression Screws

Background: Management of scaphoid nonunions with bone loss varies substantially. Commonly, internal fixation consists of a single headless compression screw. Recently, some authors have reported on the theoretical benefits of dual-screw fixation. We hypothesized that using 2 headless compression screws would impart improved stiffness over a single-screw construct. Methods: Using a cadaveric model, we compared biomechanical characteristics of a single tapered 3.5- to 3.6-mm headless compression screw with 2 tapered 2.5- to 2.8-mm headless compression screws in a scaphoid waist nonunion model. The primary outcome measurement was construct stiffness. Secondary outcome measurements included load at 1 and 2 mm of displacement, load to failure for each specimen, and qualitative assessment of mode of failure. Results: Stiffness during load to failure was not significantly different between single- and double-screw configurations ( P = .8). Load to failure demonstrated no statistically significant difference between single- and double-screw configurations. Using a qualitative assessment, the double-screw construct maintained rotational stability more than the single-screw construct ( P = .029). Conclusions: Single- and double-screw fixation constructs in a cadaveric scaphoid nonunion model demonstrate similar construct stiffness, load to failure, and load to 1- and 2-mm displacement. Modes of failure may differ between constructs and represent an area for further study. The theoretical benefit of dual-screw fixation should be weighed against the morphologic limitations to placing 2 screws in a scaphoid nonunion.

Improving dispersive mixing in compatibilized polystyrene/polyamide-6 blends via extension-dominated reactive single-screw extrusion

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hao Chen ◽  
João M. Maia
Keyword(s):  
Phase Transition ◽  
Crystalline Phase ◽  
Reactive Extrusion ◽  
Polyamide 6 ◽  
Single Plane ◽  
Single Screw ◽  
Single Screw Extrusion ◽  
Double Plane ◽  
Dispersive Mixing ◽  
Crystalline Phase Transition

Abstract Extensional mixing elements (EMEs) that impose extension-dominated flow via stationary single-plane or double-plane hyperbolic converging-diverging channels were previously designed for twin-screw and single-screw extruders (TSE and SSE, respectively). In a recently published work by the authors, reactive extrusion was performed on PS/PA6 polymer blends TSE using EMEs and a crystalline phase transition of the minor phase in these droplets was observed as the size of droplet decreases from micron to submicron. Herein, we expand upon this work to SSE and study: a) The ability of the EMEs to improve dispersive mixing in the same blends; b) Assess the possibility of achieving the same crystalline phase transition in SSEs. The final blends were characterized by DSC, rheologically and morphologically via SEM, and the results show that while EME-based SSE leads to much improved mixing, better than non-EME TSE, the reduction in size of the PA6 disperse phase is not enough to induce the phase transition observed in EME-based TSE.

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