Thermal and pasting properties of cassava starch-dehydrated orange pulp blends
9
Citation
20
Reference
10
Related Paper
Citation Trend
Abstract:
Instant mixtures are easy to prepare and frequently present functional appeals. A quality parameter for instant mixtures is their rheological behavior. This study aimed at evaluating the effects of extrusion parameters on the pasting properties of cassava (Manihot esculenta L.) starch and dehydrated orange (Citrus sinensis (L.) Osbeck) pulp mixtures. The variable parameters were moisture of mixtures (12.5 to 19%), barrel temperature (40 to 90ºC) and screw rotation (170 to 266 rpm). The extruded mixtures did not show gelatinization enthalpy. Moisture had the greatest effect on paste properties. The initial pasting viscosity (before heating) of RVA (Rapid visco analyzer) is the most relevant parameter to instant mixtures. The highest cold viscosity values were obtained when mixtures were extruded under high moisture and high screw speed. High moisture (19.5%), intermediate temperature (65ºC) and screw speed (218 rpm) led to extruded mixtures production with low component degradation.The technological specificity of the continuous extrusion forming for Ag-Cu alloy and the effects of several process parameters, such as extrusion temperature, extrusion wheel rate, extrusion ratio and flash gap, on the process were analyzed and discussed. Based on theory analysis and calculation, the extrusion temperature of continuouse extrusion process for Ag-Cu alloy was given, it was about 485～500℃; and the proper extrusion wheel rate could be confirmed according to the extrusion temperature. At last, it was confirmed by analysing the qualities of products under different processing parameters.
Cite
Citations (0)
Extrusion cooking
Texture (cosmology)
Cite
Citations (22)
AZ10,AZ31,AZ61 and AZ91 magnesium alloys were deformed with simulated extrusion system on Gleeble 1500D,which can determine the extrusion force during extrusion forming process.The microstructure of the alloys and the evolution of extrusion force were investigated.The results show that the extrusion force increases gradually with the increase of alloy element.Aimed at the same magnesium alloy,the deformed alloy with previous homogenization before extrusion has more extrusion force than that without homogenization,and dynamic recrystallization is a decisive factor in extrusion force during extrusion forming.
Homogenization
Dynamic Recrystallization
Cite
Citations (0)
In terms of the features of indirect aluminum extrusion,an analysis is made concerning the trend of exit temperature of aluminum profile in the course of extrusion operation.The simulation has been carried out of the indirect extrusion process by means of FEM.As a result,the variety trend,at different extrusion speeds,of both indirect extrusion force and exit temperature of aluminum profile has been gained.On the basis of the above research,an isothermal extrusion is put forward,that is,the working stroke is divided into several different zones and the extrusion speed shall be decreased gradually in the period of extrusion.
Isothermal process
Cite
Citations (2)
This paper deals with a finite element model (FEM) for the extrusion of AZ31 alloy and extrusion experiments at different temperatures. The simulation is utilized to predict the extrusion force and strain at different temperatures. ES (extrusion-shear) process and direct extrusion are investigated at 370, 400 and 420°C to discuss the effects of different temperatures on the microstructures and mechanical properties with the extrusion ratio of 11.56. The simulation results obtained show that the extrusion force of ES process is much larger than direct extrusion because of the two corners. ES process could effectively refine the grains, especially the microstructure of the central region compared with direct extrusion. The bar extruded at 370°C shows the best microstructures and mechanical properties.
Bar (unit)
Cite
Citations (1)
The main emphasis of this study was to utilize thixoextrusion process for improving extrudability of 7075, 7003 Al wrought alloys and AZ31 Mg wrought alloy. The results of thixbextrusion experiments about microstructures and extrusion pressures were compared with conventional hot extrusion results. The maximum extrusion pressure of thixoextrusion was greatly decreased compared with that of conventional hot extrusion. It was pointed out that the extrusion temperature dependence of the maximum extrusion pressure was large and the influence of extrusion temperature on the improvement of extrudability was remarkable in thixoextrusion. This will contribute to extrudability in terms of extrusion pressure, which in turn means that shorter process time is required and smaller extrusion machine can be applied for the same operation. The elongated grains to extrusion direction were generally observed during conventional hot extrusion, while the thixoextruded microstructures were isotropic.
Cite
Citations (0)
Abstract Hot extrusion is a process in which wrought parts are formed by forcing a heated billet through a shaped die opening. This article discusses nonlubricated and lubricated hot extrusion. The two nonlubricated hot extrusion methods are forward or direct extrusion and backward or indirect extrusion. The article illustrates the significance of extrusion speeds and temperatures in hot extrusion. It describes the basic types of presses used in the hot extrusion of metals. The article provides information on the characterization of extruded shapes and explains the operating parameters, including extrusion velocity, amount of pressure required, and type of lubricant, for successful and efficient hot extrusion. The article concludes with a discussion on applications and design methodology that provides insight into CAD/CAM of extrusion dies.
Cite
Citations (12)
Cite
Citations (4)
At present, the extrusion force formulas used in calculating backward extrusion are all based on the according direct extrusion's, and the friction between the metals and inside of the container is assumed to become zero. In practice, the calculated extrusion force according to these formulas has much difference with the real figure frequently, which can not guide production. The main reason is to neglect the difference of the temperature rice and strain hardening between the direct extrusion and the backward extrusion. Through the experiment, the backward extrusion force formulas were found. The error of backward extrusion force calculated by the formulas is not more than 5%, so it can be applied in engineering calculation.
Cite
Citations (0)
By the aid of the comparison experiment of direct extrusion with backward extrusion, the varying law of extrusion force and the difference of maximum extrusion force between direct and backward extrusion were studied. The experiment results show that in backward extruding bars, the extrusion force increases with extrusion process and reaches the maximum value which is about 10% smaller than that in direct extrusion at the end of the extrusion process, and this phenomenon is opposite to that in direct extrusion; in backward extruding pipes, the extrusion force reaches the maximum value which is about 30% smaller than that in direct extrusion at the beginning of basic extrusion stage and then decreases with extrusion process and reaches a constant in end. This phenomenon is similar to that in direct extrusion.
Cite
Citations (0)