scholarly journals Influence of annealing on the polycarbonate stretching process

2014 ◽  
Author(s):  
A. Wibbeke ◽  
A. Göttlicher ◽  
V. Schöppner
Keyword(s):  
Stretching Process

The Applications of Vibratory Stress Relief in High-Strength Aluminum Alloy Thick Plate

2012 ◽  
Vol 430-432 ◽  
pp. 881-885
Author(s):  
Cai Jun Gan ◽  
Kai Liao
Keyword(s):  
Aluminum Alloy ◽  
Residual Stresses ◽  
Dimensional Stability ◽  
Strain Energy ◽  
Thick Plate ◽  
High Strength ◽  
Stress Relief ◽  
High Strength Aluminum Alloy ◽  
Mechanical Stretching ◽  
Stretching Process

The level and distribution of residual stresses have great impact on dimensional stability, while Vibratory Stress Relief (VSR) is an effective technology to relax or homogenize residual stresses. Experimental study on residual stresses distribution, residual strain energy and machining deformation of 7075 high-strength aluminum alloy thick plate under different aging process status shows that VSR can effectively decrease the amplitude and strain energy density, and enhance stability of dislocation structures and phase states in metal microscopic volume, then internal residual stresses are homogenized to enhance components’ anti-deformation capacity. In addition, the capability in maintaining dimensional stability from VSR is better than that from traditional mechanical stretching process

Promotion of polysulfone membrane by thermal-mechanical stretching process

2013 ◽  
Vol 20 (3) ◽  
Author(s):  
Farzaneh Mahmoudi ◽  
Ehsan Saljoughi ◽  
Seyed Mahmoud Mousavi
Keyword(s):  
Polysulfone Membrane ◽  
Mechanical Stretching ◽  
Stretching Process

Physical properties of biaxially oriented PA6 film for simultaneous stretching and sequential processing

2011 ◽  
Vol 31 (1) ◽  
Author(s):  
Masao Takashige ◽  
Toshitaka Kanai
Keyword(s):  
Impact Strength ◽  
Physical Properties ◽  
Physical Property ◽  
High Impact ◽  
Thermal Shrinkage ◽  
Double Bubble ◽  
Biaxial Stretching ◽  
High Impact Strength ◽  
The Difference ◽  
Stretching Process

Abstract There are two different stretching processes that produce the biaxially oriented film, namely the tenter process and double bubble tubular film process. Furthermore, there are two tenter processes, i.e., the sequential biaxial stretching process and simultaneous biaxial stretching process. There is no report describing the difference among film physical properties of the three different processes. The biaxially oriented polyamide film using the double bubble tubular process has good balanced physical property and high impact strength, thus it is used for proper applications utilizing their advantage properties. In this report, the influence of each biaxial stretching process on film physical properties of polyamide, which has hydrogen bond, was studied in detail. As a result, the tentering process film has anisotropic tensile properties between machine direction (MD) and transverse direction (TD). This result was influenced by a later stretching process, namely TD stretching. On the contrary, the double bubble tubular film has good balanced properties, especially thermal shrinkage and impact strength. Tentering simultaneous stretching film has much larger shrinkage in MD than in TD. The sequential stretching film has larger shrinkage in TD than in MD. The double bubble tubular film has high impact strength, because it corresponds to the balanced molecular orientation.

scholarly journals Identification of the Process of Dynamic Stretching of Threads in Warp Knitting Technology Part II: Experimental Identification of the Process of Stretching Threads, with Verification of Rheological Models

2018 ◽  
Vol 18 (1) ◽  
pp. 1-6
Author(s):  
Aleksandra Prążyńska ◽  
Zbigniew Mikołajczyk
Keyword(s):  
Standard Model ◽  
Theoretical Analysis ◽  
Theoretical Data ◽  
Dynamic Processes ◽  
Rheological Models ◽  
Zener Model ◽  
Measuring Device ◽  
Experimental Identification ◽  
Research Material ◽  
Stretching Process

Abstract The study is a continuation of the first part of the publication, concerning the theoretical analysis of sensitivity of rheological models of dynamically stretched thread. This part presents the experimental research on the characteristics of stretching forces as a function of time, in the context of comparing the obtained results with theoretical data. The selected research material was three types of polyester silk threads with linear densities 84, 110 and 334 dtex. During the tests, threads of 400 to 1300 mm were stretched at speeds in the range of V ∈ [0.65, 1.47] m/s, which corresponds to the knitting speed n ∈ [700, 1600] courses/min. An original measuring device for empirical identification of dynamic processes of threads stretching was used during the tests. In total, 36 tests variants were performed. The procedures of mathematical equivalence were also worked out for the rheological models of Kelvin-Voigt, Zener and the three-parameter Standard model 2, which enabled the description of threads stretching phenomena in technological processes with the help of generalized rheological model, taking into account the visco-elastic qualities of threads. Experimental results showed that for the assumed deformation speeds ε(t) ∈ [0.53, 4.00] 1/s, the open three-parameter models – Standard model 2 and Zener model most reliably describe the stretching process.

Wake Recovery Performance Benefit in a High-Speed Axial Compressor

2002 ◽  
Vol 124 (2) ◽  
pp. 275-284 ◽  
Author(s):  
Dale E. Van Zante ◽  
John J. Adamczyk ◽  
Anthony J. Strazisar ◽  
Theodore H. Okiishi
Keyword(s):  
High Speed ◽  
Axial Compressor ◽  
Decay Process ◽  
Operating Conditions ◽  
Rotor Wake ◽  
Stage Design ◽  
Axial Compressors ◽  
Laser Anemometer ◽  
Stretching Process ◽  
Actual Loss

Rotor wakes are an important source of loss in axial compressors. The decay rate of a rotor wake is largely due to both mixing (results in loss) and stretching (no loss accrual). Thus, the actual loss associated with rotor wake decay will vary in proportion to the amounts of mixing and stretching involved. This wake stretching process, referred to by Smith (1996) as recovery, is reversible and for a 2-D rotor wake leads to an inviscid reduction of the velocity deficit of the wake. It will be shown that for the rotor/stator spacing typical of core compressors, wake stretching is the dominant wake decay process within the stator with viscous mixing playing only a secondary role. A model for the rotor wake decay process is developed and used to quantify the viscous dissipation effects relative to those of inviscid wake stretching. The model is verified using laser anemometer measurements acquired in the wake of a transonic rotor operated alone and in a stage configuration at near peak efficiency and near stall operating conditions. Results from the wake decay model exhibit good agreement with the experimental data. Data from the model and laser anemometer measurements indicate that rotor wake straining (stretching) is the primary decay process in the stator passage. Some implications of these results on compressor stage design are discussed.

Adenosinetriphosphate, calcium and temperature requirements for the final steps of exocytosis in Paramecium cells

1978 ◽  
Vol 32 (1) ◽  
pp. 67-86
Author(s):  
H. Matt ◽  
M. Bilinski ◽  
H. Plattner
Keyword(s):  
Membrane Fusion ◽  
Cetyltrimethylammonium Bromide ◽  
Membrane Lipids ◽  
Energy Requirement ◽  
Gradient Centrifugation ◽  
Cetylpyridinium Chloride ◽  
Cationic Detergents ◽  
Matrix Bound ◽  
Membrane Resealing ◽  
Stretching Process

In Paramecium cells a synchronized discharge of trichocysts (which involves only the final exocytosis steps of membrane fusion, content discharge and membrane resealing) was achieved with ATPase-blockers, Ca2+-ionophores, lipid solvents (including lysolecithin), polyethyleneglycol, anaesthetics (Dibucain) and cationic detergents (cetyltrimethylammonium bromide (CTMAB) and cetylpyridinium chloride (CPC). Only Dibucain—and to some extent cationic detergents—can trigger exocytosis independently of extracellular Ca2+, possibly by mobilizing intracellular Ca2+. The internal free [Ca2+] necessary for exocytosis can be estimated to be greater than 10(−6) to 10(−4) M. Membrane-free trichocyst contents were isolated by density gradient centrifugation; they are converted from the contracted to the expanded state by Dibucain, CTMAB and CPC, and also by exogenous ATPase (Apyrase). Thus, it is possible to de-couple the discharge (stretching) process from membrane-related phenomena. Since only the latter are inhibited by low temperature (0 degrees C), membrane lipids probably have to be in a fluid state for exocytosis to occur. At least 2 steps appear to be involved: when membrane fusion is initiated, an independent matrix-bound system is activated for the synchronized stretching process. The energy requirement for one discharge event is estimated to be about 14 X 10(6) ATP molecules.

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