Laboratory Simulation of a Factory Extrusion Process by the Die Swell Tester

1981 ◽  
Vol 54 (2) ◽  
pp. 439-448 ◽  
Author(s):  
Noboru Tokita
Keyword(s):  
Theoretical Analysis ◽  
Correlation Coefficient ◽  
Cross Section ◽  
Residence Time ◽  
Extrusion Process ◽  
Laboratory Simulation ◽  
Die Swell ◽  
Operation Temperature ◽  
D Values

Abstract The simulation principle (scaling) of the tire tubing process was studied by the “Die Swell Tester”. It was found that once the following three conditions were established, the die swells (ratio of extrudate to die cross section) of factory tubed extrudate were identical to lab scale DS results: namely, (1) same operation temperature, (2) same residence time in die, and (3) same ratio of die length to die diameter (L/D). In order to obtain the same L/D values between the complicated die shape of a factory tuber and the circular die of the DST, it is shown that the hydraulic radii (area/perimeters) must be kept the same. The correlation coefficient between factory extrudate properties and DST values was 99.6%. On the contrary, the Mooney torque ML1 + 4 values did not correlate with the die swell properties of the factory extrudates. Cold shrinkage of cut lengths of factory extrudates was simulated by the use of an extension control attachment to the DST. The theoretical analysis of potential recovery was established using die swell values and the stretch ratios. A good correlation between potential recovery (or total stretch) and cold shrinkage was obtained in both factory and laboratory samples.

Case Analysis on PTH Fracture Caused by Twin Copper

2014 ◽  
Vol 1061-1062 ◽  
pp. 431-435
Author(s):  
Xiao He
Keyword(s):  
Thermal Analysis ◽  
Thermal Stress ◽  
Theoretical Analysis ◽  
Cross Section ◽  
Current Density ◽  
Case Analysis ◽  
Actual Case ◽  
Soldering Process ◽  
Root Cause ◽  
Section Analysis

An actual case of PTH fracture after soldering process was studied. By means of cross section analysis using metallography microscope and SEM, together with thermal analysis results, root cause of PTH fracture was concluded that a high density of twin copper weakened the mechanical strength so seriously that PTHs could not undergo thermal stress from soldering process, and higher CTE was attributed to an accelerative factor. Moreover, it is recommended to enhance current density properly and make sure the effectiveness of electroplating additives to prevent twin copper by theoretical analysis.

The Effect of the Compounding Procedure on the Morphology and Mechanical Properties of PLA/PBAT-Based Nanocomposites

2021 ◽  
Vol 36 (2) ◽  
pp. 219-227
Author(s):  
P. Saiprasit ◽  
A. K. Schlarb
Keyword(s):  
Mechanical Properties ◽  
Residence Time ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Extrusion Process ◽  
Poly Lactic Acid ◽  
Silicon Dioxide Nanoparticles ◽  
Twin Screw ◽  
One Step ◽  
Thermodynamic Driving Force

Abstract Poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT)-based nanocomposites filled with 1 vol.% silicon dioxide nanoparticles (nano-SiO2) were prepared using a co-rotating twin-screw extruder and injection molding. The nanocomposites with various blending sequences were investigated using PLA-based and PBAT-based nanocomposite masterbatches. Morphology of the PLA/PBAT/SiO2 nanocomposites was examined using a scanning electron microscope (SEM) and a focused ion beam (FIB) SEM. It is found that the nano-SiO2 locates in the original polymer phase, in which it is firstly incorporated in the masterbatch process, as well as at the interface between the two polymers. However, as the residence time in the extrusion process increases, the nanoparticles migrate from the original phase to the interface, governed by the thermodynamic driving force. The best optimization of mechanical properties is achieved by using the PBAT-based masterbatches with a one-step process or short residence time. The processing history, therefore, has a tremendous impact on the final properties of the resulting materials.

Modeling of the Ionized Fluid Flow through a Cone-Shaped Nanopore

2007 ◽  
Vol 121-123 ◽  
pp. 1089-1092 ◽  
Author(s):  
Jian Zhong Fu ◽  
Xiao Bing Mi ◽  
Yong He ◽  
Zi Chen Chen
Keyword(s):  
Fluid Flow ◽  
Theoretical Analysis ◽  
Cross Section ◽  
Debye Length ◽  
Velocity Profiles ◽  
Gradual Change ◽  
Ion Flow ◽  
Flow Through

Theoretical analysis of the ionized fluid flowing through a cone-shaped nanopore is presented. The internal cross section of the cone-shaped channel is in the range from micro- to nanometer and gradual change from larger to smaller than the Debye length for the ions. The model is developed to predict the ionized fluid flow behaviors in cone-shaped micro/nanochannels. The velocity profiles of ion flow that occur in nanopores are obtained.

THE ANOMALOUS PROCESS γπ → ππ AND ITS IMPACT ON THE π0 TRANSITION FORM FACTOR

2014 ◽  
Vol 35 ◽  
pp. 1460397
Author(s):  
BASTIAN KUBIS
Keyword(s):  
Form Factor ◽  
Phase Shift ◽  
Theoretical Analysis ◽  
Cross Section ◽  
Transition Form Factor ◽  
P Wave ◽  
Chiral Anomaly ◽  
Transition Form ◽  
Dispersive Representation ◽  
Important Input

The process γπ → ππ, in the limit of vanishing photon and pion energies, is determined by the chiral anomaly. This reaction can be investigated experimentally using Primakoff reactions, as currently done at COMPASS. We derive a dispersive representation that allows one to extract the chiral anomaly from cross-section measurements up to 1 GeV, where effects of the ρ resonance are included model-independently via the ππ P-wave phase shift. We discuss how this amplitude serves as an important input to a dispersion-theoretical analysis of the π0 transition form factor, which in turn is a vital ingredient to the hadronic light-by-light contribution to the anomalous magnetic moment of the muon.

scholarly journals Validation of a Multilag Estimator on NJU-CPOL and a Hybrid Approach for Improving Polarimetric Radar Data Quality

2020 ◽  
Vol 12 (1) ◽  
pp. 180
Author(s):  
Shiqing Shao ◽  
Kun Zhao ◽  
Haonan Chen ◽  
Jianjun Chen ◽  
Hao Huang
Keyword(s):  
Theoretical Analysis ◽  
Correlation Coefficient ◽  
Hybrid Method ◽  
Radar Data ◽  
Noise Power ◽  
Signal Power ◽  
Polarimetric Radar ◽  
Moment Estimation ◽  
Spectrum Width ◽  
Differential Reflectivity

For the estimation of weak echo with low signal-to-noise ratio (SNR), a multilag estimator is developed, which has better performance than the conventional method. The performance of the multilag estimator is examined by theoretical analysis, simulated radar data and some specific observed data collected by a C-band polarimetric radar in previous research. In this paper, the multilag estimator is implemented and verified for Nanjing University C-band polarimetric Doppler weather radar (NJU-CPOL) during the Observation, Prediction and Analysis of Severe Convection of China (OPACC) field campaign in 2014. The implementation results are also compared with theoretical analysis, including the estimation of signal power, spectrum width, differential reflectivity, and copolar correlation coefficient. The results show that the improvement of the multilag estimator is little for signal power and differential reflectivity, but significant for spectrum width and copolar correlation coefficient when spectrum width is less than 2 ms−1, which implies a large correlation time scale. However, there are obvious biases from the multilag estimator in the regions with large spectrum width. Based on the performance analysis, a hybrid method is thus introduced and examined through NJU-CPOL observations. All lags including lag 0 of autocorrelation function (ACF) are used for moment estimation in this algorithm according to the maximum usable lag number. A case study shows that this hybrid method can improve moment estimation compared to both conventional estimator and multilag estimator, especially for weak weather echoes. The improvement will be significant if SNR decreases or the biases of noise power in the conventional estimator increase. In addition, this hybrid method is easy to implement on both operational and non-operational radars. It is also expected that the proposed hybrid method will have a better performance if applied to S-band polarimetric radars which have twice the maximum useable lags in the same conditions with C-band radars.

Reconstituted Mini Tensile Specimens

2018 ◽  
Author(s):  
Attila Kovács ◽  
Ákos Horváth ◽  
Márta Horváth ◽  
Ildikó Szenthe ◽  
Ferenc Gillemot
Keyword(s):  
Fracture Toughness ◽  
Cross Section ◽  
Testing Temperature ◽  
Reference Temperature ◽  
Specific Method ◽  
Molybdenum Wire ◽  
Operation Temperature ◽  
Video Microscope ◽  
Toughness Testing ◽  
Do So

In order to evaluate the fracture toughness and Master Curve, the exact values of the tensile and yield strengths determined at the fracture toughness testing temperature are required. The fracture toughness should be measured around the T0 reference temperature to obtain valid results. Tensile properties — if exists — are generally measured at room temperature, and at the maximum operation temperature of the pressure vessel. If T0 reference temperature is different from these temperatures a correction formula is used for interpolation or extrapolation. Several times even no reliable tensile results are available, especially in the case of irradiated specimens. Use of irradiated Charpy remnants is a solution to produce tensile bars. A specific method has been developed to produce 12 pieces of flat 2*1 mm cross section tensile specimens made from one half Charpy specimens using stud weld reconstitution. The specimen cutting is made using thin molybdenum wire spark cutting. In order to do so difficulties of handling the small radioactive specimens needed to be solved, special grips were developed for the tensile machine to clamp the miniature tensile specimens. A laser extensometer was used to measure the strain and a video microscope was used to determine the cross section after the fracture without touching the specimen. The paper presents the results obtained on more than 200 irradiated small tensile specimens. These results had been compared to the old surveillance ones.

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