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Sample records for twin-screw extrusion studies

  1. Application of Twin Screw Extrusion in the Manufacture of Cocrystals, Part I: Four Case Studies

    Directory of Open Access Journals (Sweden)

    Karthik Nagapudi

    2011-08-01

    Full Text Available The application of twin screw extrusion (TSE as a scalable and green process for the manufacture of cocrystals was investigated. Four model cocrystal forming systems, Caffeine-Oxalic acid, Nicotinamide-trans cinnamic acid, Carbamazepine-Saccharin, and Theophylline-Citric acid, were selected for the study. The parameters of the extrusion process that influenced cocrystal formation were examined. TSE was found to be an effective method to make cocrystals for all four systems studied. It was demonstrated that temperature and extent of mixing in the extruder were the primary process parameters that influenced extent of conversion to the cocrystal in neat TSE experiments. In addition to neat extrusion, liquid-assisted TSE was also demonstrated for the first time as a viable process for making cocrystals. Notably, the use of catalytic amount of benign solvents led to a lowering of processing temperatures required to form the cocrystal in the extruder. TSE should be considered as an efficient, scalable, and environmentally friendly process for the manufacture of cocrystals with little to no solvent requirements.

  2. PEACH POMACE PROCESSING USING TWIN SCREW EXTRUSION

    Directory of Open Access Journals (Sweden)

    Preetam Sarkar

    2014-02-01

    Full Text Available Fruit by-products have found limited applications in the food industry. They have been primarily used as animal feed, applied to agricultural land for soil amendment or composted and applied to farms for growing crops. Some of these disposal methods are not environment friendly, while others are costly. This study was undertaken to examine the possibility of utilizing peach pomace as a source of soluble dietary fiber in expanded extruded food products. Peach pomace was combined with rice flour at four different levels. The four blends were mixed, dried to a moisture level of 13.5% (w/w and ground to flour. These blends were extruded in a twin-screw extruder (Clextral EV-25 at a feed flow rate of 15 kg/h. The extruded products were analyzed for physical and textural properties. The apparent and true densities for the extrudates decreased from 183.93 to 133.94 kg/m3 and 1275.31 to 1171.2 kg/m3, respectively. A linear increase in extrudate porosity (85.11-88.54% and radial expansion ratio (13.5-19.3 and a steady decrease in breaking strength (104-50.74 kPa were observed with increasing peach pomace level in the blends. This study demonstrates the potential of extrusion processing as a tool for fruit by-product utilization, which will not only enhance consumption of soluble dietary fiber but will also increase the overall fruit utilization.

  3. Twin-Screw Extruders in Ceramic Extrusion

    Science.gov (United States)

    Wiedmann, Werner; Hölzel, Maria

    The machines mainly used for compounding plastics, chemicals and food are co-rotating, closely intermeshing twin-screw extruders. Some 30 000 such extruders are in use worldwide, about 1/3 are ZSKs from Coperion Werner & Pfleiderer, Stuttgart. In the chemical industry more and more batch mixers are being replaced by continuous twin-screw kneaders.

  4. A phenomenological study on twin screw extruders

    NARCIS (Netherlands)

    Janssen, L.P.B.M.

    1976-01-01

    Although more and more twin screw extruders are being used in the polymer industry, the theoretical background is relatively undeveloped. The literature abounds in contradictions and often informs the reader that all extrusion problems can be solved if a certain new design is considered. The develop

  5. HA/UHMWPE Nanocomposite Produced by Twin-screw Extrusion

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The HA/UHMWPE nanocomposite is compounded by twin-screw extrusion of the HA and UHMWPE powder mixture in paraffin oil and then compression molded to a sheet form. TGA measurement shows the HA weight loss after processing is about 1%-2% . FTIR spectra indicate the paraffin oil residue is trivial and UHMWPE is not oxidized. SEM reveals the HA nano particles are homogeneously dispersed by twin- screw extrusion and the inter-particle spaces are penetrated with UHMWPE fibrils by swelling treatment. HRTEM image indicates the HA particles and UHMWPE are intimately contacted by mechanical interlocking. Compared with the unfilled UHMWPE, stiffness of the composite with the HA volume fraction 0.23 was significantly enhanced to 9 times without detriment of the yield strength and the ductility.

  6. 莲子双螺杆挤压膨化工艺的研究%Study on Extrusion Conditions of Lotus Seeds by Twin Screw Extruder

    Institute of Scientific and Technical Information of China (English)

    陈学玲; 关健; 梅新; 何建军

    2012-01-01

    以莲子为原料,采用双螺杆挤压膨化技术开发莲子膨化食品.研究了原料颗粒大小、原料含水量、进料速度、挤压膨化温度及螺杆转速等因素对莲子膨化的影响.结果表明:当莲子目数大于或等于40目时,莲子膨化较优工艺为:进料速度17~19 r/min,原料含水量14%~16%,膨化温度155~165℃,螺杆转速135~145 r/min.%Twin screw extruder was used to prepare extrusion-puffed food from Lotus seeds. The effects of material particle size and moisture content, feeding speed, extruded-cooking temperature and screw speed were studied. Through the single factor analysis, the optimal parameters of extrusion were obtained as the following: feeding speed 17 - 19 r/min, moisture content 14% - 16% , extruded-cooking temperature 155 - 165 ℃ , screw speed 135 - 145 r/min, and material particle size more than or equal to 40 mesh.

  7. Twin screw extrusion processing of distillers dried grains with solubles (DDGS)-based Yellow Perch (Perca flavescens) feeds

    Science.gov (United States)

    Increases in global aquaculture production, compounded with limited availabilities of fish meal for fish feed, has created the need for alternative protein sources. Twin-screw extrusion studies were performed to investigate the production of nutritionally-balanced feeds for juvenile yellow perch (Pe...

  8. Twin screw extrusion processing of feed blends containing distillers dried grains with solubles

    Science.gov (United States)

    Extrusion trials were conducted with varying levels of distillers dried grains with solubles (DDGS) along with soy flour, corn flour, fish meal, vitamin mix, mineral mix and net protein content adjusted to 28% using a Wenger TX-52 twin screw extruder. The properties of extrudates obtained with exper...

  9. Efficient continuous synthesis of high purity deep eutectic solvents by twin screw extrusion.

    Science.gov (United States)

    Crawford, D E; Wright, L A; James, S L; Abbott, A P

    2016-03-18

    Mechanochemical synthesis has been applied to the rapid synthesis of Deep Eutectic Solvents (DESs), including Reline 200 (choline chloride : urea, 1 : 2), in a continuous flow methodology by Twin Screw Extrusion (TSE). This gave products in higher purity and with Space Time Yields (STYs), four orders of magnitude greater than for batch methods.

  10. Modelling extrudate expansion in a twin-screw food extrusion cooking process through dimensional analysis methodology

    DEFF Research Database (Denmark)

    Cheng, Hongyuan; Friis, Alan

    2010-01-01

    A new phenomenological model is proposed to correlate extrudate expansion and extruder operation parameters in a twin-screw food extrusion cooking process. Buckingham's pi dimensional analysis method is applied to establish the model. Three dimensionless groups, i.e. pump efficiency, water content...... and temperature, are formed to model the extrusion process from dimensional analysis. The model is evaluated with experimental data for extrusion of whole wheat flour and fish feed. The average deviations of the model correlations are 5.9% and 9% based on experimental data for the whole wheat flour and fish feed...

  11. Development of Nutritious Snack from rice industry waste using twin screw extrusion

    Directory of Open Access Journals (Sweden)

    Sharma Renu

    2016-01-01

    Full Text Available Deoiled rice bran, a byproduct of rice milling industry was transformed into highly nutritious snack by the application of twin screw extrusion process. Response Surface Methodology (RSM with four- factor- five level central composite rotatable design (CCRD was employed to investigate the effects of extrusion conditions including moisture content of different raw flours, feed composition, barrel temperature and screw speed of extruder on properties of extrudates was studied. Second order quadratic regression model fitted adequately in the variation. The significance was established at P ≤ 0.05. The regression models can be used to interpret the effect of feed composition, moisture content, screw speed and barrel temperature on the properties of the final product. It was shown that higher rice bran in feed composition showed in minimum water absorption index and maximum water solubility index. Numerical optimization technique resulted in 123.83°C of barrel temperature, 294.68 rpm of screw speed, 13.94 % of feed moisture and 17.73 % of deoiled rice bran. The responses predicted for these optimum process conditions resulted water absorption index, 5.91468 g/g and water solubility index of 18.5553 % for the development of value added product with health benefits.

  12. Twin-screw extrusion for hemicellulose recovery: influence on extract purity and purification performance.

    Science.gov (United States)

    Zeitoun, Rawan; Pontalier, Pierre Yves; Marechal, Philippe; Rigal, Luc

    2010-12-01

    A twin-screw extruder was used for the extraction of wheat bran hemicelluloses by the co-extrusion of wheat straw and bran. As compared with a stirred reactor extraction, a twin-screw extruder resulted in a lower extraction rate (only about 24% of hemicelluloses in the wheat bran), but it has the advantages of a shorter residence time for the vegetable matter and a lower chemical and water consumption. Hemicellulose powder production is usually effected via an expensive alcoholic precipitation step after concentration. Ultrafiltration was investigated as a means to reduce the alcohol consumption. Trials were made with hollow fiber polyethersulfone membranes with a molecular weight cut-off of 30 kDa. Ultrafiltration mainly concentrated the extract and removed small molecules such as monosaccharides and minerals. The combination of the anion-exchange chromatography and ultrafiltration allowed for the removal of colored compounds.

  13. Acetone-butanol-ethanol production from corn stover pretreated by alkaline twin-screw extrusion pretreatment.

    Science.gov (United States)

    Zhang, Yuedong; Hou, Tongang; Li, Bin; Liu, Chao; Mu, Xindong; Wang, Haisong

    2014-05-01

    In this study, the alkaline twin-screw extrusion pretreated corn stover was subjected to enzymatic hydrolysis after washing. The impact of solid loading and enzyme dose on enzymatic hydrolysis was investigated. It was found that 68.2 g/L of total fermentable sugar could be obtained after enzymatic hydrolysis with the solid loading of 10 %, while the highest sugar recovery of 91.07 % was achieved when the solid loading was 2 % with the cellulase dose of 24 FPU/g substrate. Subsequently, the hydrolyzate was fermented by Clostridium acetobutylicum ATCC 824. The acetone-butanol-ethanol (ABE) production of the hydrolyzate was compared with the glucose, xylose and simulated hydrolyzate medium which have the same reducing sugar concentration. It was shown that 7.1 g/L butanol and 11.2 g/L ABE could be produced after 72 h fermentation for the hydrolyzate obtained from enzymatic hydrolysis with 6 % solid loading. This is comparable to the glucose and simulated hydrozate medium, and the overall ABE yield could reach 0.112 g/g raw corn stover.

  14. Nanoporous nanocomposite membranes via hybrid twin-screw extrusion-multijet electrospinning.

    Science.gov (United States)

    Senturk-Ozer, Semra; Aktas, Seda; He, Jing; Fisher, Frank T; Kalyon, Dilhan M

    2017-01-13

    Non-woven nanoporous membranes of poly(caprolactone), PCL, incorporated with multi-walled carbon nanotubes, CNTs, could be fabricated via an industrially-scalable hybrid twin screw extrusion and electrospinning process. The utilization of a spinneret with multiple nozzles allowed the increase of the flow rate beyond what is possible with conventional electrospinning using a single nozzle, albeit at the expense of difficulties in the control of the thickness distributions of the nanofibrous membranes. The thickness and orientation distributions and the resulting mechanical properties of the membranes could be modified via changes in voltage, angular velocity of the collector mandrel and separation distance of the collector from the spinneret. The increases in crystallinity due to the presence of the CNTs and the preferential alignment of the nanofibers via rotation of the collecting mandrel led to increases in the tensile properties of the nanoporous membranes. The use of poly(ethylene oxide), PEO, together with PCL, followed by the dissolution of the PEO, rendered the nanofibers themselves nanoporous with typical surface porosity values of around 50% and pore sizes of about 220 nm. The demonstrated versatility of the hybrid twin screw extrusion and electrospinning process and the manipulation of mesh dimensions and properties are indicative of the applicability of the hybrid process for fabrication of nanoporous membranes for myriad diverse industrial applications ranging from water treatment to tissue engineering applications.

  15. Engineering Aspects of Single- and Twin-screw Extrusion-cooking of Biopolymers

    NARCIS (Netherlands)

    Zuilichem, D.J. van; Stolp, W.; Janssen, L.P.B.M.

    1983-01-01

    A survey is given of the properties of single- and twin-screw extruders. The influence on the design of the different leakage gaps existing in co-rotating, counter-rotating, self-wiping, twin-screw extruders and single-screw equipment is discussed. The mixing effects in single- and twin-screw equipm

  16. Effect of Some Extrusion Variables on Rheological Properties and Physicochemical Changes of Cornmeal Extruded by Twin Screw Extruder

    Directory of Open Access Journals (Sweden)

    Chang Y.K.

    1998-01-01

    Full Text Available The effect of extrusion variables, such as barrel temperature (100 to 170ºC, feed rate (100 to 500 g/min, feed moisture (20 to 40 g/100 g wet basis, screw speed rate (from 100 to 500 rpm, and slit die rheometer configuration (0.15 and 0.30 cm height were studied using a co-rotating intermeshing twin-screw extruder coupled to a slit die rheometer on the rheological properties of yellow cornmeal. An increase in feed rate decreased WAI and WSI, but increased the viscosity values. The temperature interacts strongly with screw speed in affecting the WSI. The most important factor in starch degradation was the screw speed. Increasing the screw speed completely modifies the organised structure of starch (crystalline region.

  17. Reduction of Ochratoxin A in Oat Flakes by Twin-Screw Extrusion Processing.

    Science.gov (United States)

    Lee, Hyun Jung; Dahal, Samjhana; Perez, Enrique Garcia; Kowalski, Ryan Joseph; Ganjyal, Girish M; Ryu, Dojin

    2017-10-01

    Ochratoxin A (OTA) is one of the most important mycotoxins owing to its widespread occurrence and toxicity, including nephrotoxicity and potential carcinogenicity to humans. OTA has been detected in a wide range of agricultural commodities, including cereal grains and their processed products. In particular, oat-based products show a higher incidence and level of contamination. Extrusion cooking is widely used in the manufacturing of breakfast cereals and snacks and may reduce mycotoxins to varying degrees. Hence, the effects of extrusion cooking on the stability of OTA in spiked (100 μg/kg) oat flake was investigated by using a laboratory-scale twin-screw extruder with a central composite design. Factors examined were moisture content (20, 25, and 30% dry weight basis), temperature (140, 160, and 180°C), screw speed (150, 200, and 250 rpm), and die size (1.5, 2, and 3 mm). Both nonextruded and extruded samples were analyzed for reductions of OTA by high-performance liquid chromatography, coupled with fluorescence detection. The percentage of reductions in OTA in the contaminated oat flakes upon extrusion processing were in the range of 0 to 28%. OTA was partially stable during extrusion, with only screw speed and die size having significant effect on reduction (P < 0.005). The highest reduction of 28% was achieved at 180°C, 20% moisture, 250 rpm screw speed, and a 3-mm die with 193 kJ/kg specific mechanical energy. According to the central composite design analyses, up to 28% of OTA can be reduced by a combination of 162°C, 30% moisture, and 221 rpm, with a 3-mm die.

  18. Application of twin screw extrusion to the manufacture of cocrystals: scale-up of AMG 517-sorbic acid cocrystal production.

    Science.gov (United States)

    Daurio, Dominick; Nagapudi, Karthik; Li, Lan; Quan, Peter; Nunez, Fernando-Alvarez

    2014-01-01

    The application of twin screw extrusion (TSE) in the scale-up of cocrystal production was investigated by using AMG 517-sorbic acid as a model system. Extrusion parameters that influenced conversion to the cocrystal such as temperature, feed rate and screw speed were investigated. Extent of conversion to the cocrystal was found to have a strong dependence on temperature and a moderate dependence on feed rate and screw speed. Cocrystals made by the TSE process were found to have superior mechanical properties than solution grown cocrystals. Additionally, moving to a TSE process eliminated the need for solvent.

  19. Continuously graded extruded polymer composites for energetic applications fabricated using twin-screw extrusion processing technology

    Science.gov (United States)

    Gallant, Frederick M.

    A novel method of fabricating functionally graded extruded composite materials is proposed for propellant applications using the technology of continuous processing with a Twin-Screw Extruder. The method is applied to the manufacturing of grains for solid rocket motors in an end-burning configuration with an axial gradient in ammonium perchlorate volume fraction and relative coarse/fine particle size distributions. The fabrication of functionally graded extruded polymer composites with either inert or energetic ingredients has yet to be investigated. The lack of knowledge concerning the processing of these novel materials has necessitated that a number of research issues be addressed. Of primary concern is characterizing and modeling the relationship between the extruder screw geometry, transient processing conditions, and the gradient architecture that evolves in the extruder. Recent interpretations of the Residence Time Distributions (RTDs) and Residence Volume Distributions (RVDs) for polymer composites in the TSE are used to develop new process models for predicting gradient architectures in the direction of extrusion. An approach is developed for characterizing the sections of the extrudate using optical, mechanical, and compositional analysis to determine the gradient architectures. The effects of processing on the burning rate properties of extruded energetic polymer composites are characterized for homogeneous formulations over a range of compositions to determine realistic gradient architectures for solid rocket motor applications. The new process models and burning rate properties that have been characterized in this research effort will be the basis for an inverse design procedure that is capable of determining gradient architectures for grains in solid rocket motors that possess tailored burning rate distributions that conform to user-defined performance specifications.

  20. Development of Maltodextrin-Based Immediate-Release Tablets Using an Integrated Twin-Screw Hot-Melt Extrusion and Injection-Molding Continuous Manufacturing Process.

    Science.gov (United States)

    Puri, Vibha; Brancazio, Dave; Desai, Parind M; Jensen, Keith D; Chun, Jung-Hoon; Myerson, Allan S; Trout, Bernhardt L

    2017-07-04

    The combination of hot-melt extrusion and injection molding (HME-IM) is a promising process technology for continuous manufacturing of tablets. However, there has been limited research on its application to formulate crystalline drug-containing immediate-release tablets. Furthermore, studies that have applied the HME-IM process to molded tablets have used a noncontinuous 2-step approach. The present study develops maltodextrin (MDX)-based extrusion-molded immediate-release tablets for a crystalline drug (griseofulvin) using an integrated twin-screw HME-IM continuous process. At 10% w/w drug loading, MDX was selected as the tablet matrix former based on a preliminary screen. Furthermore, liquid and solid polyols were evaluated for melt processing of MDX and for impact on tablet performance. Smooth-surfaced tablets, comprising crystalline griseofulvin solid suspension in the amorphous MDX-xylitol matrix, were produced by a continuous process on a twin-screw extruder coupled to a horizontally opening IM machine. Real-time HME process profiles were used to develop automated HME-IM cycles. Formulation adjustments overcame process challenges and improved tablet strength. The developed MDX tablets exhibited adequate strength and a fast-dissolving matrix (85% drug release in 20 min), and maintained performance on accelerated stability conditions. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  1. Extrusion trials with a TSK045 twin screw extruder (Poster presentation)

    NARCIS (Netherlands)

    Sabel, H.W.R.; Schonewille, E.

    1998-01-01

    In 1994 a 45mm twin screw extruder was introduced at the Prins Maurits Laboratory of TNO for the processing of energetic materials. Initial safety experiments were carried out by using inert compositions with small amounts of different energetic components and micro encapsulated chemical sensors to

  2. Extrusion trials with a TSK045 twin screw extruder (Poster presentation)

    NARCIS (Netherlands)

    Sabel, H.W.R.; Schonewille, E.

    1998-01-01

    In 1994 a 45mm twin screw extruder was introduced at the Prins Maurits Laboratory of TNO for the processing of energetic materials. Initial safety experiments were carried out by using inert compositions with small amounts of different energetic components and micro encapsulated chemical sensors to

  3. Preparation of gluten-free rice spaghetti with soy protein isolate using twin-screw extrusion.

    Science.gov (United States)

    Detchewa, Pakkawat; Thongngam, Masubon; Jane, Jay-Lin; Naivikul, Onanong

    2016-09-01

    The objective of this study was to investigate the effect of soy protein isolate on functional properties and consumer acceptance of gluten-free rice spaghetti (GFRS) made from rice flour. Dry-milled high-amylose (Chai Nat 1) rice flour was premixed with dry-milled waxy (RD 6) rice flour at a ratio of 90:10 (w/w) with the soy protein isolate (SPI) concentration varying between 0, 2.5, 5.0, 7.5, 10.0 %, db. The GFRS formulation was processed using a co-rotating twin-screw extruder up to 95 °C with a screw speed of 220 rpm, 32 % moisture content, and then dried at 40 °C. The GFRS samples were analyzed by differential scanning calorimetry (DSC), X-ray diffraction, scanning electron microscopy (SEM) and texture parameters. Increasing SPI decreased the starch retrogradation of GFRS, whereas the enthalpy change of the amylose-lipid complex increased and crystallinity decreased. SEM revealed that the surface of GFRS containing SPI was much more porous than that of GFRS without SPI. The cooked GFRS containing 5.0 % SPI showed the best eating quality with increased firmness and tensile strength, and decrease stickiness. The GFRS samples were evaluated on the bases of cooking qualities and sensory evaluation. The results showed that the GFRS containing 5.0 % SPI decrease the cooking time from 17.6 to 13.7 min and cooking loss from 25.4 to 17.0 %. Overall acceptability of cooked GFRS containing 5.0 % SPI was the highest among all GFRS samples.

  4. Twin screw wet granulation: the study of a continuous twin screw granulator using Positron Emission Particle Tracking (PEPT) technique.

    Science.gov (United States)

    Lee, Kai T; Ingram, Andy; Rowson, Neil A

    2012-08-01

    In this paper, Positron Emission Particle Tracking (PEPT) techniques are utilised to track the trajectory of single particles through the mixing and conveying zones of a Twin Screw Granulator (TSG). A TSG consisting of conveying zones and mixing zones is used in this study. The mixing zones are arranged with kneading discs at an angle of 30°, 60° or 90°. Experiments were carried out using different mixing configurations with various screw speed and total mass flow rate. The PEPT data obtained were then utilised to obtain the residence time distribution (RTD) and the Peclet number in an attempt to gain some insight into the mixing of the process. The fill level of the granulator was also estimated to study the mechanism of granulation. As might be expected, it was shown that the residence time of the granulation process increases with decreasing screw speed. It also increases with increasing angle of the arrangement of kneading blocks in the mixing zones, but will decreases when powder feed rate is increased. The fill level of the mixing zone in particular increases when the screw speed decreases or when powder feed rate increases. Furthermore, the fill level of the granulator will increase when the mixing zone configuration changes from 30° to 90°. It is shown that the granulator is never fully filled, even using 90° mixer elements implying limited compaction which may explain why the granules produced are porous compared with those from a high shear mixer. Interestingly, the RTD analysis reveals that the extent of axial mixing in the mixing zone of the granulator does not change significantly for different configurations and process conditions. There is evidence of a tail in the RTD which implies some material hold up and channelling.

  5. Extrusion cooking using a twin-screw apparatus reduces toxicity of fumonisin-contaminated corn grits

    Science.gov (United States)

    Extrusion cooking using a single screw configuration reduced fumonisin concentrations of corn grits in an earlier study. Adding glucose before cooking enhanced reductions and, in one of three trials, partially reversed in vivo toxicity. To determine the effectiveness of extrusion using the more effi...

  6. Twin screw extrusion of kodo millet-chickpea blend: process parameter optimization, physico-chemical and functional properties.

    Science.gov (United States)

    Geetha, R; Mishra, H N; Srivastav, P P

    2014-11-01

    Kodo millet-chickpea flour blend (70:30) was explored for development of directly expanded snack by twin-screw extrusion. Effect of process parameters like temperature (80-150 °C), screw speed (250-300 rpm) and feeder speed (15-30 rpm) on physical properties (expansion ratio, bulk density, hardness, crispiness) of extrudates were investigated and optimized using response surface methodology. Desirable crispy extrudates were obtained at higher screw speed 293 rpm, lower feeder speed 19 rpm, and medium to high temperature of 123 °C. Effect of extreme and intermediate process conditions on functional, proximate quality and colour of the extrudates were also evaluated.

  7. Foam granulation: new developments in pharmaceutical solid oral dosage forms using twin screw extrusion machinery.

    Science.gov (United States)

    Thompson, M R; Weatherley, S; Pukadyil, R N; Sheskey, P J

    2012-07-01

    This paper investigates foam granulation in a twin screw extruder as a new continuous wet granulation technique for pharmaceutical powder drug formulations. Foamed aqueous binder has a reportedly lower soak-to-spread ratio than drop or spray liquid addition in batch granulation. This work demonstrates a twin screw extruder configuration for foam granulation and subsequently compares the new approach against liquid injection in the granulation of α-lactose monohydrate with a methylcellulose binder. Trials were conducted at high powder output rates (20-40 kg/h) and high screw speeds (220-320 RPM) with two screw configurations. Process stability improved with the new technique allowing granulation with less binder. The extruded mass maintained a low exit temperature, being insensitive to operating conditions unlike the liquid injection approach, where temperatures rose significantly as flow rate increased. The particle size distribution by foam granulation reflected a more uniformly wetted mass with larger granule growth noted even for conditions where dry powder exited by liquid injection. Other factors were found similar between the two binder delivery methods such as consumed mechanical energy, as well as fracture strength and compressibility of produced granules.

  8. Mechanistic studies on the release of lysozyme from twin-screw extruded lipid implants.

    Science.gov (United States)

    Sax, Gerhard; Winter, Gerhard

    2012-10-28

    The influence of lipid melting on the in-vitro release of lysozyme from twin-screw extruded lipid implants was investigated. Triglyceride based implants were prepared by admixing of glycerol tristearin and various low melting lipids and subsequent twin-screw extrusion (tsc-extrusion) of these mixtures at moderate temperatures. Lysozyme was embedded as model protein and PEG 4000 or PEG 6000 was used as pore-forming excipient. By decreasing the amount of pore-forming agent from 40% to 0% lysozyme release became more sustained and the release kinetics changed from a matrix-type release profile to a linear release profile. Differential scanning calorimetry, X-ray diffraction and scanning electron microscopy measurements showed a change in implant structure upon long-term release (240 days) at 37 °C which was explained by partial matrix melting. In addition, partial melting of the implants was found to facilitate complete drug release at 37 °C whereas at 20 °C without partial melting 20% to 90% of the incorporated protein remained trapped in the implant matrix. In conclusion, partial melting of the implants during in-vitro release was found to be a major factor for the control of protein release from extruded implants and can be useful to trigger release, achieve in-vivo biodegradability and complete long-term protein release.

  9. Numerical study on mixing performance of glass fiber dispersion in a twin-screw extruder with backward-mixing elements

    Science.gov (United States)

    Hirata, Kunihiro; Ishida, Hiroshi; Hiragori, Motohiro; Nakayama, Yasuya; Kajiwara, Toshihisa

    2015-05-01

    In the kneading of glass-fiber-reinforced plastics by twin-screw extrusion, the use of a backward-mixing screw (BMS) element for melt mixing has been found to be effective in dispersing glass-fiber bundles. In this study, we use the computational fluid dynamics (CFD) to study the mechanism of dispersion by a BMS element for glass fiber bundles. The result of CFD for a BMS and a forward kneading disk (FKD) reveals that the melt mixing by a BMS is highly effective to act the required stress on overall resin. In addition, there is a good correlation between the incidence of undispersed glass-fiber bundles measured experimentally and the minimum value of distribution of the time-integrated stress calculated numerically. On the basis of the above results, we propose a method to predict the operating conditions in which the incident probability of undispersed glass-fiber bundles and thermal degradation are controlled.

  10. Soluplus®/TPGS-based solid dispersions prepared by hot-melt extrusion equipped with twin-screw systems for enhancing oral bioavailability of valsartan

    Directory of Open Access Journals (Sweden)

    Lee JY

    2015-05-01

    Full Text Available Jae-Young Lee,1,* Wie-Soo Kang,2,* Jingpei Piao,2 In-Soo Yoon,3 Dae-Duk Kim,1 Hyun-Jong Cho4 1College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 2School of Bioscience and Biotechnology, Kangwon National University, Chuncheon, 3College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Jeonnam, 4College of Pharmacy, Kangwon National University, Chuncheon, Republic of Korea *These authors contributed equally to this work Background: Soluplus® (SP and ᴅ-alpha-tocopherol polyethylene glycol 1000 succinate (TPGS–based solid dispersion (SD formulations were developed by hot-melt extrusion (HME to improve oral bioavailability of valsartan (VST. Methods: HME process with twin-screw configuration for generating a high shear stress was used to prepare VST SD formulations. The thermodynamic state of the drug and its dispersion in the polymers were evaluated by solid-state studies, including Fourier-transform infrared, X-ray diffraction, and differential scanning calorimetry. Drug release from the SD formulations was assessed at pH values of 1.2, 4.0, and 6.8. Pharmacokinetic study was performed in rats to estimate the oral absorption of VST. Results: HME with a high shear rate produced by the twin-screw system was successfully applied to prepare VST-loaded SD formulations. Drug amorphization and its molecular dispersion in the polymer matrix were verified by several solid-state studies. Drug release from SD formulations was improved, compared to the pure drug, particularly at pH 6.8. Oral absorption of drug in rats was also enhanced in SP and TPGS-based SD groups compared to that in the pure drug group. Conclusion: SP and TPGS-based SDs, prepared by the HME process, could be used to improve aqueous solubility, dissolution, and oral absorption of poorly water-soluble drugs. Keywords: hot-melt extrusion, oral bioavailability, solid dispersion, valsartan  

  11. Twin screw granulation - review of current progress.

    Science.gov (United States)

    Thompson, M R

    2015-01-01

    Twin screw granulation (TSG) is a new process of interest to the pharmaceutical community that can continuously wet granulate powders, doing so at lower liquid concentrations and with better product consistency than found by a high shear batch mixer. A considerable body of research has evolved over the short time since this process was introduced but generally with little comparison of results. A certain degree of confidence has been developed through these studies related to how process variables and many attributes of machinery configuration will affect granulation but some major challenges still lay ahead related to scalability, variations in the processing regimes related to degree of channel fill and the impact of wetting and granulation of complex powder formulations. This review examines the current literature for wet granulation processes studied in twin screw extrusion machinery, summarizing the influences of operational and system parameters affecting granule properties as well as strives to provide some practical observations to newly interested users of the technique.

  12. Development of rheological characterization and twin-screw extrusion/spiral winding processing methods for functionally-graded tissue engineering scaffolds and characterization of cell/biomaterial interactions

    Science.gov (United States)

    Ozkan, Seher

    Tissue engineering involves the fabrication of biodegradable scaffolds, on which various types of cells are grown, to provide tissue constructs for tissue repair/regeneration. Native tissues have complex structures, with functions and properties changing spatially and temporally, and require special tailoring of tissue engineering scaffolds to allow mimicking of their complex elegance. The understanding of the rheological behavior of the biodegradable polymer and the thermo-mechanical history that the polymer experiences during processing is critical in fabricating scaffolds with appropriate microstructural distributions. This study has first focused on the rheological material functions of various gel-like fluids including biofluids and hydrogels, which can emulate the viscoelastic behavior of biofluids. Viscoplasticity and wall slip were recognized as key attributes of such systems. Furthermore, a new technology base involving twin-screw extrusion/spiral winding (TSESW) process was developed for the shaping of functionally-graded scaffolds. This novel scaffold fabrication technology was applied to the development of polycaprolactone (PCL) scaffolds, incorporated with tricalcium phosphate nanoparticles and various porogens in graded fashion. The protein encapsulation and controlled release capabilities of the TSESW process was also demonstrated by dispersing bovine serum albumin (BSA) protein into the PCL matrix. Effects of processing conditions and porosity distributions on compressive properties, surface topography, encapsulation efficiency, release profiles and the secondary structure of BSA were investigated. The PCL scaffolds were determined to be biocompatible, with the proliferation rates of human fetal osteoblast cells (hFOB) increasing with increasing porosity and decreasing concentration of TCP. BSA proteins were determined to be denatured to a greater extent with melt extrusion in the 80-100°C range (in comparison to wet extrusion using organic

  13. Influence of crystallinity on the fracture toughness of poly(lactic acid)/montmorillonite nanocomposites prepared by twin-screw extrusion

    OpenAIRE

    Gamez Pérez, José; De Nascimento, L.; Bou Serra, Jordi; FRANCO URQUIZA, EDGAR ADRIAN; Santana Pérez, Orlando Onofre; Carrasco Alonso, Félix Ángel; Maspoch Rulduà, Mª Lluïsa

    2011-01-01

    The aim of this work was to study the effect of crystallinity degree on the thermal, mechanical, and fracture properties of poly(lactic acid)/organomodified montmorillonite (PLA/OMMT) nanocomposites. Samples with two different compositions (0.5 and 2.5% weight OMMT in PLA) were prepared by melt mixing in a twin-screw extruder and injection molding. An annealing treatment was applied to increase the percentage of PLA crystallinity. The thermal behavior was analyzed by differential scanning cal...

  14. The influence of specific mechanical energy on cornmeal viscosity measured by an on-line system during twin-screw extrusion

    Directory of Open Access Journals (Sweden)

    CHANG Y. K.

    1999-01-01

    Full Text Available The influence of specific mechanical energy (SME on cornmeal viscosity during the twin-screw extrusion at feed moisture contents of 25 and 30% and screw speeds in the range from 100 to 500 rpm was measured. Cornmeal was extruded in a co-rotating, intermeshing twin-screw coupled to a slit die rheometer. One approach to the on-line rheological measurement is to use a slit die with the extruder. In the present work it was show that shear viscosity decreased as a function of SME. The viscosity of cornmeal at the exit die was influenced by screw speed, rate of total mass flow, mass temperature inside the extruder and SME. An increase in screw speed resulted in an increase in SME and a decrease in viscosity. A reduction in slit die height and an increase in screw speed and mass temperature led to a remarkable macromolecular degradation of the starch, as evidenced by the decrease in viscosity.

  15. Study on Hardware-in-loop Simulation of Twin-screw Extruder Experiment System

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>In order to facilitate the teaching of industrial processes and experiments on the twin-screw extruder control debugging,and be closer to the actual testing,to reduce the debugging costs and the risk of debugging process,the paper designs a hardware-in-loop simulation of twin-screw extruder experiment system which is closer to scene,low cost and high safety.The system through the establishment of twin-screw extruder’s mathematical model on computer to simulate the realistic system and there is hardware practicality in the computer simulation loop.The hardware based on C8051F020 can operate in the simulation loop in real time.In computer software design, we desigh man-machine interface that is intuitive and easy to operate,can reflect twin-screw extruder main operation information vividly.Finally,twin-screw extruder’s 3 heater temperature mathematical model and PID incremental control algorithm are presented.

  16. Process design and control of a twin screw hot melt extrusion for continuous pharmaceutical tamper-resistant tablet production.

    Science.gov (United States)

    Baronsky-Probst, J; Möltgen, C-V; Kessler, W; Kessler, R W

    2016-05-25

    Hot melt extrusion (HME) is a well-known process within the plastic and food industries that has been utilized for the past several decades and is increasingly accepted by the pharmaceutical industry for continuous manufacturing. For tamper-resistant formulations of e.g. opioids, HME is the most efficient production technique. The focus of this study is thus to evaluate the manufacturability of the HME process for tamper-resistant formulations. Parameters such as the specific mechanical energy (SME), as well as the melt pressure and its standard deviation, are important and will be discussed in this study. In the first step, the existing process data are analyzed by means of multivariate data analysis. Key critical process parameters such as feed rate, screw speed, and the concentration of the API in the polymers are identified, and critical quality parameters of the tablet are defined. In the second step, a relationship between the critical material, product and process quality attributes are established by means of Design of Experiments (DoEs). The resulting SME and the temperature at the die are essential data points needed to indirectly qualify the degradation of the API, which should be minimal. NIR-spectroscopy is used to monitor the material during the extrusion process. In contrast to most applications in which the probe is directly integrated into the die, the optical sensor is integrated into the cooling line of the strands. This saves costs in the probe design and maintenance and increases the robustness of the chemometric models. Finally, a process measurement system is installed to monitor and control all of the critical attributes in real-time by means of first principles, DoE models, soft sensor models, and spectroscopic information. Overall, the process is very robust as long as the screw speed is kept low.

  17. Preparation of Nutritional Coarse Grain Powder by Twin-Screw Extrusion%膨化营养杂粮粉的挤压制备工艺研究

    Institute of Scientific and Technical Information of China (English)

    郑志; 王丽娟; 杨雪飞; 祁斌; 赖华楠; 姜绍通

    2012-01-01

    分别以80目玉米粉、糙米粉、燕麦粉、麦麸粉作为营养杂粮粉生产原料,研究物料含水量、螺杆转速、机筒温度对产品品质指标径向膨化度、糊化度和吸水性指数的影响,在此基础上设计正交试验,确定挤压技术制备膨化营养杂粮粉的最佳工艺参数为物料含水量15%、螺杆转速130r/min、机筒温度160℃,此时产品径向膨化度为3.26,糊化度为91.87%,吸水性指数为491.8%。%Nutritional coarse grain powder was developed using twin-screw extrusion technology with mixed powder of corn, unpolished rice, oat and wheat bran. The effects of water content in raw materials, screw speed and barrel temperature on quality indices including radial expansion degree, gelatinizafion degree and water-absorbing capacity of extruded powder were investigated. An orthogonal array design was used to determine the optimal process parameters for the preparation of nutritional coarse grain powder as follows: water content in raw materials of 15%, screw speed of 130 r/min, and barrel temperature of 160 ℃. The radial expansion degree, gelatinization degree and water-absorbing capacity of the obtained product were 3.26, 91.87 % and 491.8 %, respectively.

  18. 高蛋白冲调糊粉双螺杆挤压技术%Production of High-protein Instant Powder with Twin-screw Extrusion

    Institute of Scientific and Technical Information of China (English)

    唐静; 钱建亚

    2015-01-01

    以黑豆为主料,红豆、玉米、糙米、糯米为辅料,应用线性规划设计配方,按所得配方:黑豆35%,红豆15%,玉米32%,糯米10%,糙米8%进行单因素试验,探讨机筒温度、水含量和螺杆转速等工艺条件对产品堆积密度、水含量、产品直径、色差、糊化度、吸水性指数和水溶性指数等主要品质指标的影响. 以糊化度和感官评分为指标进行正交试验,获得最佳工艺条件为:物料水含量20g/100g,机筒温度155℃,螺杆转速30Hz.%With black beans as the main material and red beans, corn, brown rice and glutinous rice as auxil-iary materials, a formula was designed by linear programming: black beans 35%, red beans 15%, corn 32%, glutinous rice 10%and brown rice 8%.Carrying out single factor experiment on the formula, the au-thor investigated into the effect of twin-screw extrusion conditions, barrel temperature, moisture content and screw speed on main quality indexes of the product, bulk density, moisture content, expanded diameter, color value, gelatinization, water absorption index and water solubility index.Taking gelatinization value and senso-ry evaluation as the indicators, further optimization of technology was implemented with the orthogonal test to gain the best product.The optimal conditions were: moisture content 20g/100g, extruder barrel temperature 155℃, and screw speed 30Hz.

  19. Functionally graded scaffolds for the engineering of interface tissues using hybrid twin screw extrusion/electrospinning technology

    Science.gov (United States)

    Erisken, Cevat

    Tissue engineering is the application of the principles of engineering and life sciences for the development of biological alternatives for improvement or regeneration of native tissues. Native tissues are complex structures with functions and properties changing spatially and temporally, and engineering of such structures requires functionally graded scaffolds with composition and properties changing systematically along various directions. Utilization of a new hybrid technology integrating the controlled feeding, compounding, dispersion, deaeration, and pressurization capabilities of extrusion process with electrospinning allows incorporation of liquids and solid particles/nanoparticles into polymeric fibers/nanofibers for fabrication of functionally graded non-woven meshes to be used as scaffolds in engineering of tissues. The capabilities of the hybrid technology were demonstrated with a series of scaffold fabrication and cell culturing studies along with characterization of biomechanical properties. In the first study, the hybrid technology was employed to generate concentration gradations of beta-tricalcium phosphate (beta-TCP) nanoparticles in a polycaprolactone (PCL) binder, between two surfaces of nanofibrous scaffolds. These scaffolds were seeded with pre-osteoblastic cell line (MC3T3-E1) to attempt to engineer cartilage-bone interface, and after four weeks, the tissue constructs revealed formation of continuous gradations in extracellular matrix akin to cartilage-bone interface in terms of distributions of mineral concentrations and biomechanical properties. In a second demonstration of the hybrid technology, graded differentiation of stem cells was attempted by using insulin, a known stimulator of chondrogenic differentiation, and beta-glycerol phosphate (beta-GP), for mineralization. Concentrations of insulin and beta-GP in PCL were controlled to monotonically increase and decrease, respectively, along the length of scaffolds, which were then seeded

  20. Dissolving cellulose with twin-screw extruder in a NaOH complex aqueous solution

    Science.gov (United States)

    Yang, Y. P.; Zhang, Y.; Dawelbeit, A.; Yu, M. H.

    2016-07-01

    Novel cellulose dissolution method with twin-screw extruder was developed in order to improve the dissolution property, to simplify production procedure and to produce cellulose spinning dope which is stable and which has a higher concentration of cellulose. Therefore, the extrusion conditions on the cellulose dissolution in NaOH/thiourea/urea were extensively studied in this work. The resulted extrudates of twin-screw extruder dissolution method were characterized by polarized optical microscope image, the solubility experiment and the apparent viscosity. The results revealed that the screw revolution speed of such process could improve the solubility value (S a) of cellulose, and the solubility of cellulose reached a maximum value of 7.5 wt% at higher revolutions 450 rpm. On the other hand, the cellulose solutions were more transparent and balanced with its apparent viscosity values lower and more stable compare to stirring method, which indicated dissolving cellulose with twin-screw extruder was reliable. Moreover, the whole dissolving time is quite short, and the process is simple. The soluble effect of twin screw extrusion was far superior to traditional stirring, and the most suitable temperature was -2°C.

  1. THE SELF-WIPING CO-ROTATING TWIN-SCREW EXTRUDER AS A POLYMERIZATION REACTOR FOR METHACRYLATES

    NARCIS (Netherlands)

    Jongbloed, H.A.; Kiewiet, J.A.; van Dijk, J.H.; Janssen, L.P.B.M.

    1995-01-01

    The self-wiping co-rotating twin-screw extruder was studied as a reactor for two polymerizations in bulk: the homopolymerization of n-butylmethacrylate and the copolymerization of n-butylmethacrylate with 2-hydroxypropylmethacrylate. The influence of the extrusion parameters on the product was analy

  2. A comparative study of ground tire rubber devulcanization using twin screw extruder and internal mixer

    Science.gov (United States)

    Ujianto, O.; Putri, D. B.; Jayatin; AWinarto, D.

    2017-07-01

    Devulcanization of ground tire rubber (GTR) was done using twin screw extruder (TSE) and internal mixer (IM). Processing parameters were varied to analyze its effect on gel content. Fourier Transform Infrared Spectroscopy (FTIR) analysis was performed as qualitative technique to confirm structural change. The devulcanized rubbers with the least gel content percentage produced in both TSE and IM were then used as filler in natural rubber (NR)/coconut coir (CC) composite preparation. Effects of gel content percentage on NR/CC composite tensile strength and elongation at break were analyzed. The results show that the gel content decreased by 41% for sample processed in TSE and 50% in IM compared to control sample. Overall, the devulcanization is influenced by high energy generated by thermal or thermo-mechanical process. FTIR spectra show chemically structural changes of GTR as C=C, CH2, CH3 with higher intensity for IM sample than its counterpart indicated devulcanization. The replacement of GTR to DGTR on NR/CC/GTR composites provided less network structures and resulted better tensile strength and elongation at break.

  3. In-line solid state prediction during pharmaceutical hot-melt extrusion in a 12 mm twin screw extruder using Raman spectroscopy.

    Science.gov (United States)

    Saerens, Lien; Ghanam, Dima; Raemdonck, Cedric; Francois, Kjell; Manz, Jürgen; Krüger, Rainer; Krüger, Susan; Vervaet, Chris; Remon, Jean Paul; De Beer, Thomas

    2014-08-01

    The aim of this research was to use Raman spectroscopy for the in-line monitoring of the solid state of materials during pharmaceutical hot-melt extrusion in the die head of a 12 mm (development scale) twin-screw extruder during formulation development. A full factorial (mixed) design was generated to determine the influence of variations in concentration of Celecoxib (CEL) in Eudragit® E PO, three different screw configurations and varying barrel temperature profiles on the solid state, 'melt temperature' and die pressure of continuously produced extrudates in real-time. Off-line XRD and DSC analysis were used to evaluate the suitability of Raman spectroscopy for solid state predictions. First, principal component analysis (PCA) was performed on all in-line collected Raman spectra from the experimental design. The resulting PC 1 versus PC 2 scores plot showed clustering according to solid state of the extrudates, and two classes, one class where crystalline CEL is still present and a second class where no crystalline CEL was detected, were found. Then, a soft independent modelling of class analogy (SIMCA) model was developed, by modelling these two classes separately by disjoint PCA models. These two separate PCA models were then used for the classification of new produced extrudates and allowed distinction between glassy solid solutions of CEL and crystalline dispersions of CEL. All extrudates were classified similarly by Raman spectroscopy, XRD and DSC measurements, with exception of the extrudates with a 30% CEL concentration extruded at 130 °C. The Raman spectra of these experiments showed bands which were sharper than the amorphous spectra, but broader than the crystalline spectra, indicating the presence of CEL that has dissolved into the matrix and CEL in its crystalline state. XRD and DSC measurements did not detect this. Modifications in the screw configuration did not affect the solid state and did not have an effect on the solid state prediction of

  4. Behavior of Escherichia coli bacteria in whey protein and corn meal during twin screw extrusion processing at different temperatures

    Science.gov (United States)

    Many studies on the development of new and/ or value added nutritional meal corn and whey protein isolates for US consumers have been reported. However, information on the effect of treatment parameters on microbial safety of foods extruded below 100 deg C is limited. In this study, we investigated ...

  5. A study of concentrated acid hydrolysis conversion of lignocellulosic materials to sugars using a co-rotating twin-screw reactor extruder and plug flow reactor

    Science.gov (United States)

    Miller, William Scott

    Concerns about the ability of petroleum to continue supplying ever increasing global energy demands, at a price capable of generating continued economic growth, have spurred innovative research in the field of alternative energy. One alternative energy option that has the ability to provide long-term sustainable energy supplies for the global energy market is the conversion of lignocellulosic materials, via acid hydrolysis, to fermentable sugars for the production of fuel grade ethanol. This research demonstrates the ability of a co-rotating twin-screw reactor extruder and plug flow reactor to continuously convert lignocellulosic materials to fermentable sugars using high temperature concentrated acid hydrolysis. In addition to demonstrating continuous operation of the two-stage concentrated acid hydrolysis system, a number of design of experiments were conducted to model the twin-screw performance and maximize its ability to effectively solubilize lignocellulosic feedstocks in the high shear, elevated temperature, concentrated acid environment. These studies produced a base case twin-screw operating condition used to generate a standard extrudate composition for an extensive high temperature acid hydrolysis batch reactor kinetic modeling study. In this study a number of nonlinear and linear regression analyses were undertaken so that the concentration of less resistant cellulose, or the amount of solublilized extrudate cellulose, resistant cellulose, or non-solubilized extrudate cellulose, glucose, and decomposition products could be obtained as a function of time, temperature, and acid concentration. This study demonstrated that the theoretical cellulose conversion of 51% was limited by the amount of solubilized polysaccharides that could be produced in the twin-screw pretreatment. Further experimentation, showing twin-screw pretreatment lignocellulosic versatility, produced nearly identical results as the southern yellow pine sawdust experiments that were

  6. A Simple-to-Implement Simulator for the Reactive Extrusion of Poly(Lactic Acid in a Corotating Uniform Twin-Screw Extruder

    Directory of Open Access Journals (Sweden)

    René O. Vargas

    2015-01-01

    Full Text Available The present paper deals with the poly(lactic acid (PLA reactive processing simulation in a uniform corotating twin-screw extruder that can be readily turned into practical applications in pilot and industrial equipment. The simulator provides a cause-effect guide that can be useful for starting an experimental setup in a reactive screw extruder for a biopolymer in a growing industry. The proposed model considers a free radical ring-opening mechanism involving the main characteristic flows inside the extruder and the non-Newtonian behavior of PLA. The characteristic behavior relating reaction rate, average molecular weights, and polydispersity against chamber number are described by S-shaped and monotonically decreasing curves, for the equipment. Numerical predictions show that this simple and easy to implement model accurately reproduces previously reported data and that the impurity concentration exhibits a marked effect over all the variables, except conversion.

  7. Twin screw granulation: steps in granule growth.

    Science.gov (United States)

    Dhenge, Ranjit M; Cartwright, James J; Hounslow, Michael J; Salman, Agba D

    2012-11-15

    The present work focuses on the study of the progression of granules in different compartments along the length of screws in a twin screw granulator (TSG). The effects of varying powder feed rate; liquid to solid ratio and viscosity of granulation liquid on properties of granules was studied. The bigger granules produced at the start of the process were found to change in terms of size, shape and strength along the screw length at all the conditions investigated. The granules became more spherical and their strength increased along the screw length. Tracer granules were also introduced in order to understand the role of kneading and conveying elements in the TSG. The kneading elements promoted consolidation and breakage while the conveying elements led to coalescence, breakage and some consolidation. The results presented here help to provide a qualitative and quantitative understanding of the twin screw granulation process.

  8. Improving the API dissolution rate during pharmaceutical hot-melt extrusion I: Effect of the API particle size, and the co-rotating, twin-screw extruder screw configuration on the API dissolution rate.

    Science.gov (United States)

    Li, Meng; Gogos, Costas G; Ioannidis, Nicolas

    2015-01-15

    The dissolution rate of the active pharmaceutical ingredients in pharmaceutical hot-melt extrusion is the most critical elementary step during the extrusion of amorphous solid solutions - total dissolution has to be achieved within the short residence time in the extruder. Dissolution and dissolution rates are affected by process, material and equipment variables. In this work, we examine the effect of one of the material variables and one of the equipment variables, namely, the API particle size and extruder screw configuration on the API dissolution rate, in a co-rotating, twin-screw extruder. By rapidly removing the extruder screws from the barrel after achieving a steady state, we collected samples along the length of the extruder screws that were characterized by polarized optical microscopy (POM) and differential scanning calorimetry (DSC) to determine the amount of undissolved API. Analyses of samples indicate that reduction of particle size of the API and appropriate selection of screw design can markedly improve the dissolution rate of the API during extrusion. In addition, angle of repose measurements and light microscopy images show that the reduction of particle size of the API can improve the flowability of the physical mixture feed and the adhesiveness between its components, respectively, through dry coating of the polymer particles by the API particles.

  9. 操作参数对双螺杆挤压机挤压效果影响的研究%Study on Operation Parameters of Extruding Grain Mixes by a Twin-Screw Extruder

    Institute of Scientific and Technical Information of China (English)

    杨绮云; 李德溥; 徐克非

    2001-01-01

    通过实验研究了荞麦、黑米、薏米三种谷物的混合物料为原料时,双螺杆挤压机的螺杆转速、物料湿度、机筒温度三种操作参数对双螺杆挤压机的挤压膨化效果(以糊化度衡量)的影响。依据可旋转中心组合实验设计及实验数据建立了相关的统计模型,通过对响应面和等高线的分析,得出了三种操作参数的最佳取值范围。本实验研究对于开发谷物膨化食品、探索双螺杆挤压机加工谷物原料的挤压机理具有重要的现实意义。%Abstract The effects of varying screw speed, barrel temperatureand moisture content on extrusion quality(expressed as degree of dextrinization)of materials comprised of buckwheat, melan-rice and coix were studied by using a co-rotating twin-screw extruder. The statistical model was established by using a rotate central composite design and response surface methodology. The operation parameters were conducted by triaxial contour map and isohypsic analysis. The experiment results showed great significance of exploitation of grist extrudate and the mechanism of the twin-screw extruder.

  10. Continuous twin-screw granulation for enhancing the dissolution of poorly water soluble drug.

    Science.gov (United States)

    Maniruzzaman, Mohammed; Nair, Arun; Renault, Maxcene; Nandi, Uttom; Scoutaris, Nicholaos; Farnish, Richard; Bradley, Michael S A; Snowden, Martin J; Douroumis, Dennis

    2015-12-30

    The article describes the application of a twin-screw granulation process to enhance the dissolution rate of the poorly water soluble drug, ibuprofen (IBU). A quality-by-design (QbD) approach was used to manufacture IBU loaded granules via hot-melt extrusion (HME) processing. For the purpose of the study, a design of experiment (DoE) was implemented to assess the effect of the formulation compositions and the processing parameters. This novel approach allowed the use of, polymer/inorganic excipients such as hydroxypropyl methylcellulose (HPMC) and magnesium aluminometasilicate (Neusilin(®)-MAS) with polyethylene glycol 2000 (PEG) as the binder without requiring a further drying step. IBU loaded batches were processed using a twin screw extruder to investigate the effect of MAS/polymer ratio, PEG amount (binder) and liquid to solid (L/S) ratios on the dissolution rates, mean particle size and the loss on drying (LoD) of the extruded granules. The DoE analysis showed that the defined independent variables of the twin screw granulation process have a complex effect on the measured outcomes. The solid state analysis showed the existence of partially amorphous IBU state which had a significant effect on the dissolution enhancement in acidic media. Furthermore, the analysis obtained from the surface mapping by Raman proved the homogenous distribution of the IBU in the extruded granulation formulations.

  11. Effect of Twin-screw Extrusion Conditions on Soluble Dietary Fiber Content of Rice Bran%双螺杆挤出工艺对米糠可溶性膳食纤维含量的影响

    Institute of Scientific and Technical Information of China (English)

    刘婷婷; 张传智; 浦静舒; 王大为

    2011-01-01

    采用双螺杆挤出技术对米糠进行处理,增加米糠中功能性成分的含量。在单因素试验的基础上,以可溶性膳食纤维得率为指标,采用响应面法优化最佳挤出工艺。结果表明:影响米糠中可溶性膳食纤维得率的各因素强弱次序为:挤出温度〉水分含量〉物料粒度;当挤出温度170℃、水分含量35%、物料粒度80目(0.175mm)时,米糠可溶性膳食纤维得率20.85%,与理论值接近。%On the basis of one-factor-at-a-time experiments,response surface methodology was employed for the optimization of process parameters for the twin-screw extrusion of rice bran.Soluble dietary fiber(SDF) content in extruded rice bran was investigated with respect to extrusion temperature,material moisture content and material granularity.The process parameters were ranked in decreasing order of their effect on SDF content in extruded rice bran as follows: extrusion temperature,material moisture content and material granularity.After extrusion at 170 ℃,the SDF content of 80 mesh(0.175 mm) rice bran with a moisture content of 35% was determined to be 20.85%,close to the model-predicted value.

  12. Impact of microcrystalline cellulose material attributes: a case study on continuous twin screw granulation.

    Science.gov (United States)

    Fonteyne, Margot; Correia, Ana; De Plecker, Sofie; Vercruysse, Jurgen; Ilić, Ilija; Zhou, Qi; Vervaet, Chris; Remon, Jean Paul; Onofre, Fernanda; Bulone, Vincent; De Beer, Thomas

    2015-01-30

    The International Conference on Harmonisation (ICH) states in its Q8 'Pharmaceutical Development' guideline that the manufacturer of pharmaceuticals should have an enhanced knowledge of the product performance over a range of material attributes, manufacturing process options and process parameters. The present case study evaluates the effect of unspecified variability of raw material properties upon the quality attributes of granules; produced using a continuous from-powder-to-tablet wet granulation line (ConsiGma™ 25). The impact of different material attributes of six samples of microcrystalline cellulose (MCC) was investigated. During a blind study the different samples of MCC were used separately and the resulting granules were evaluated in order to identify the differences between the six samples. Variation in size distribution due to varying water binding capacity of the MCC samples was observed. The cause of this different water binding capacity was investigated and was caused by a different degree of crystallinity. Afterwards, an experimental design was conducted in order to evaluate the effect of both product and process variability upon the granule size distribution. This model was used in order to calculate the required process parameters to obtain a preset granule size distribution regardless of the type of MCC used. The difference in water binding capacity and its effect on granular properties was still present when combining the MCC grades with different binders. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Twin Screw Mixer/Fine Grind Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The 40-mm Twin-Screw Mixer/Extruder (TSE) pilot plant is a continuous, remotely operated, flexible facility that can significantly enhance safety and environmental...

  14. Twin screw subsurface and surface multiphase pumps

    Energy Technology Data Exchange (ETDEWEB)

    Dass, P. [CAN-K GROUP OF COMPANIES, Edmonton, Alberta (Canada)

    2011-07-01

    A new subsurface twin screw multiphase pump has been developed to replace ESP and other artificial lift technologies. This technology has been under development for a few years, has been field tested and is now going for commercial applications. The subsurface twin screw technology consists of a pair of screws that do not touch and can be run with a top drive or submersible motor; and it carries a lot of benefits. This technology is easy to install and its low slippage makes it highly efficient with heavy oil. In addition twin screw multiphase pumps are capable of handling high viscosity fluids and thus their utilization can save water when used in thermal applications. It also induces savings of chemicals because asphaltenes do not break down easily as well as a reduction in SOR. The subsurface twin screw multiphase pump presented herein is an advanced technology which could be used in thermal applications.

  15. Physical properties of extrudates containing distillers grains extruded in a twin screw extruder

    Science.gov (United States)

    Extrusion trials were conducted with varying levels of distillers dried grains with solubles (DDGS) along with soy flour, corn flour, fish meal, vitamin mix, mineral mix and net protein content adjusted to 28% using a Wenger TX-52 twin screw extruder. The properties of extrudates obtained with exper...

  16. Transfer from high-shear batch to continuous twin screw wet granulation: a case study in understanding the relationship between process parameters and product quality attributes.

    Science.gov (United States)

    Beer, Paul; Wilson, David; Huang, Zhenyu; De Matas, Marcel

    2014-10-01

    A twin screw to high-shear batch granulation technology switch was evaluated for a pharmaceutical development project. Differences in granule (particle size distribution and porosity) and tablet (dissolution) quality attributes were analysed for both continuous and batch technologies. Liquid to solid (L/S) ratio, screw configuration and screw speed parameters on the twin screw granulator were varied, with output granule and tablet properties characterised. L/S and screw configuration were found to influence the granule particle size distribution, porosity and tablet dissolution. At 0.15 L/S, the particle size distribution showed a significant proportion of ungranulated material in the output granule. As the L/S is increased, the level of ungranulated material decreased. An increase in L/S and the number of kneader elements caused a decrease in granule porosity and tablet dissolution. Twin screw and batch granulation technologies generated different granule properties (size and shape) at a constant L/S. A lower L/S in twin screw granulation was needed to achieve similar tablet attributes. It is concluded that differences in liquid addition and therefore initial granule nucleation caused differences in granule properties, which impacted tablet attributes and manufacturability.

  17. Development and Optimization of a Wet Granulation Process at Elevated Temperature for a Poorly Compactible Drug Using Twin Screw Extruder for Continuous Manufacturing.

    Science.gov (United States)

    Meena, Anuprabha K; Desai, Divyakant; Serajuddin, Abu T M

    2017-02-01

    The objective of this study was to enhance tabletability of a poorly compactible drug, acetaminophen, by wet granulation using twin screw extruder at high temperature. It was desired that there would be minimum amounts of excipients used and the granules obtained after extrusion would be dry and fall within a size range suitable for tableting without any further processing. Mixtures of acetaminophen (95%) with binders (5% povidone or partially pregelatinized starch) were wet granulated through twin screw extruder at 70°C by adding 7% w/w water. The process had a short granulation time (90% granules in the size range of 125 to 1000 μm (1.7 MPa, which was superior to that of tablets prepared by conventional high shear wet granulation. As the granules could be extruded continuously and did not require drying and milling, the method was amenable to continuous processing.

  18. Numerical Simulation and Performance Analysis of Twin Screw Air Compressors

    Directory of Open Access Journals (Sweden)

    W. S. Lee

    2001-01-01

    Full Text Available A theoretical model is proposed in this paper in order to study the performance of oil-less and oil-injected twin screw air compressors. Based on this model, a computer simulation program is developed and the effects of different design parameters including rotor profile, geometric clearance, oil-injected angle, oil temperature, oil flow rate, built-in volume ratio and other operation conditions on the performance of twin screw air compressors are investigated. The simulation program gives us output variables such as specific power, compression ratio, compression efficiency, volumetric efficiency, and discharge temperature. Some of the above results are then compared with experimentally measured data and good agreement is found between the simulation results and the measured data.

  19. Enzymatic hydrolysis of steam exploded corncob residues after pretreatment in a twin-screw extruder

    Directory of Open Access Journals (Sweden)

    Jun Zheng

    2014-09-01

    Full Text Available A modified twin-screw extruder incorporated with a filtration device was used as a liquid/solid separator for xylose removal from steam exploded corncobs. A face centered central composite design was used to study the combined effects of various enzymatic hydrolysis process variables (enzyme loading, surfactant addition, and hydrolysis time with two differently extruded corncobs (7% xylose removal, 80% xylose removal on glucose conversion. The results showed that the extrusion process led to an increase in cellulose crystallinity, while structural changes could also be observed via SEM. A quadratic polynomial model was developed for predicting the glucose conversion and the fitted model provided an adequate approximation of the true response as verified by the analysis of variance (ANOVA.

  20. Continuous twin screw melt granulation of glyceryl behenate: Development of controlled release tramadol hydrochloride tablets for improved safety.

    Science.gov (United States)

    Keen, Justin M; Foley, Connor J; Hughey, Justin R; Bennett, Ryan C; Jannin, Vincent; Rosiaux, Yvonne; Marchaud, Delphine; McGinity, James W

    2015-06-20

    Interest in granulation processes using twin screw extrusion machines is rapidly growing. The primary objectives of this study were to develop a continuous granulation process for direct production of granules using this technique with glyceryl behenate as a binder, evaluate the properties of the resulting granules and develop controlled release tablets containing tramadol HCl. In addition, the granulation mechanism was probed and the polymorphic form of the lipid and drug release rate were evaluated on stability. Granules were prepared using a Leistritz NANO16 twin screw extruder operated without a constricting die. The solid state of the granules were characterized by differential scanning calorimetry and X-ray diffraction. Formulated tablets were studied in 0.1N HCl containing 0-40% ethanol to investigate propensity for alcohol induced dose dumping. The extrusion barrel temperature profile and feed rate were determined to be the primary factors influencing the particle size distribution. Granules were formed by a combination immersion/distribution mechanism, did not require subsequent milling, and were observed to contain desirable polymorphic forms of glyceryl behenate. Drug release from tablets was complete and controlled over 16 h and the tablets were determined to be resistant to alcohol induced dose dumping. The drug release rate from the tablets was found to be stable at 40°C and 75% relative humidity for the duration of a 3 month study.

  1. Twin screw wet granulation: Binder delivery.

    Science.gov (United States)

    Saleh, Mohammed F; Dhenge, Ranjit M; Cartwright, James J; Hounslow, Michael J; Salman, Agba D

    2015-06-20

    The effects of three ways of binder delivery into the twin screw granulator (TSG) on the residence time, torque, properties of granules (size, shape, strength) and binder distribution were studied. The binder distribution was visualised through the transparent barrel using high speed imaging as well as quantified using offline technique. Furthermore, the effect of binder delivery and the change of screw configuration (conveying elements only and conveying elements with kneading elements) on the surface velocity of granules across the screw channel were investigated using particle image velocimetry (PIV). The binder was delivered in three ways; all solid binder incorporated with powder mixture, 50% of solid binder mixed with powder mixture and 50% mixed with water, all the solid binder dissolved in water. Incorporation of all solid binder with powder mixture resulted in the relatively longer residence time and higher torque, narrower granule size distribution, more spherical granules, weaker big-sized granules, stronger small-sized granules and better binder distribution compared to that in other two ways. The surface velocity of granules showed variation from one screw to another as a result of uneven liquid distribution as well as shown a reduction while introducing the kneading elements into the screw configuration.

  2. Twin Screw Extruders as Continuous Mixers for Thermal Processing: a Technical and Historical Perspective.

    Science.gov (United States)

    Martin, Charlie

    2016-02-01

    Developed approximately 100 years ago for natural rubber/plastics applications, processes via twin screw extrusion (TSE) now generate some of the most cutting-edge drug delivery systems available. After 25 or so years of usage in pharmaceutical environments, it has become evident why TSE processing offers significant advantages as compared to other manufacturing techniques. The well-characterized nature of the TSE process lends itself to ease of scale-up and process optimization while also affording the benefits of continuous manufacturing. Interestingly, the evolution of twin screw extrusion for pharmaceutical products has followed a similar path as previously trodden by plastics processing pioneers. Almost every plastic has been processed at some stage in the manufacturing train on a twin screw extruder, which is utilized to mix materials together to impart desired properties into a final part. The evolution of processing via TSEs since the early/mid 1900s is recounted for plastics and also for pharmaceuticals from the late 1980s until today. The similarities are apparent. The basic theory and development of continuous mixing via corotating and counterrotating TSEs for plastics and drug is also described. The similarities between plastics and pharmaceutical applications are striking. The superior mixing characteristics inherent with a TSE have allowed this device to dominate other continuous mixers and spurred intensive development efforts and experimentation that spawned highly engineered formulations for the commodity and high-tech plastic products we use every day. Today, twin screw extrusion is a battle hardened, well-proven, manufacturing process that has been validated in 24-h/day industrial settings. The same thing is happening today with new extrusion technologies being applied to advanced drug delivery systems to facilitate commodity, targeted, and alternative delivery systems. It seems that the "extrusion evolution" will continue for wide

  3. Hot-melt granulation in a twin screw extruder: effects of processing on formulations with caffeine and Ibuprofen.

    Science.gov (United States)

    Weatherley, Sharleen; Mu, Bo; Thompson, Michael R; Sheskey, Paul J; O'Donnell, Kevin P

    2013-12-01

    Hot-melt granulation (HMG) by twin screw extrusion is a novel technology for the continuous processing of pharmaceuticals but confidence must still be gained regarding whether the environment affects drug properties. In this preliminary study, granulation was studied for a model product containing lactose monohydrate and active ingredients of differing water solubility, namely ibuprofen versus caffeine. The formulations were granulated at 220 rpm and 100°C with polyethylene glycol binders of differing molecular weights and at concentrations between 6.5% and 20%. In terms of granule properties, the low melting point of ibuprofen had a dominant influence by producing larger, stronger granules, whereas the caffeine products were more comparable to a blank containing no active ingredient. Drug degradation was study by differential scanning calorimetry, X-ray diffraction, and high-pressure liquid chromatography. The only detected change was the dehydration of lactose monohydrate for the caffeine and blank products, whereas the lubricating influence of the ibuprofen protected its granules. The short residence time (∼60 s) was consider to be influential in minimizing damage of the drug despite the high temperature and shear attributed to HMG inside a twin screw extruder.

  4. COST ESTIMATES OF TWIN SCREW EXTRUDED PRODUCTS: TEXTURIZED WHEY PROTEIN SNACKS AND CORN-SOY BLEND USED FOR EMERGENCY FEEDING

    Science.gov (United States)

    The operating costs associated with twin screw extrusion cooking of various foods are fixed for a given size and production capacity for any class of products; the greater percentage of costs arise from the choice of ingredients and the product end use. For example, extruder texturized whey proteins...

  5. Investigation of melting in a modular intermeshing co-rotating twin screw extruder

    Science.gov (United States)

    Jung, Ho-Chul

    Since the first patent regarding the co-rotating twin screw extruder was published in 1869, the co-rotating twin screw extruder has evolved into a high performance extruder, having self wiping capability, modular screw configuration, starved feed zone, kneading disc block elements, and special mixing devices. For this device, flow studies began in the mid 1960's but melting studies started in the early 1990's. Former researchers have insisted on their own melting mechanisms because they found different melting mechanisms under their limited and unsystematic experimental conditions. In this dissertation, melting mechanisms were studied systemically to determine when they occur according to the various process operating conditions. This melting study was carried out using an amorphous polymer: polystyrene (PS), two semi-crystalline polymers: linear low density polyethylene (LLDPE) and polypropylene (PP), one powder type LLDPE, and four LLDPE compounds with aluminum flake or calcium carbonate, which were used to provide differences in filler size or content. We observed the screw melting initiation and melting propagation first and categorized melting regimes such as screw melting initiation (SM) internal melting initiation (IM) and barrel melting initiation (BM) as melting initiation mechanisms, and screw melting propagation internal melting propagation barrel melting propagation and bed instability (BI) as melting propagation mechanisms. We translated these melting initiation mechanisms and melting propagation mechanisms into mathematical models. Then we integrated these models into user friendly commercial software, Akro-Co-Twin ScrewR, developed previously at our laboratories. We simulated several homopolymers at various operating conditions using the Akro-Co-Twin ScrewR. The simulation results were compared with the experimental results and were found to be in good agreement within the range of simulation. Using this software, twin screw extruder process

  6. Vibrational spectroscopy to support the link between rheology and continuous twin-screw melt granulation on molecular level: A case study.

    Science.gov (United States)

    Monteyne, Tinne; Heeze, Liza; Oldörp, Klaus; Vervaet, Chris; Remon, Jean-Paul; De Beer, Thomas

    2016-06-01

    Twin screw hot melt granulation (TSHMG) is an innovative and continuous drug formulation process allowing granulation of moisture sensitive drugs. However, due to the lack of experience and in-depth process understanding, this technique is not yet widely used. During the TSHMG process, the microstructure of the granules is generated and modified and strongly depends on the flow behavior of the material. Hence, rheology might be a suitable tool to simulate and examine this process. However, chemical interactions of the material are influencing the physical properties leading to the microstructure. In this research project it is spectroscopically investigated whether the heat applied in a rheometer induces the same molecular effects as these occurring during TSHMG of the model formulation caffeine anhydrous/Soluplus®. Hence, it is evaluated whether rheology can be used as a simulation tool to improve the understanding of the material behavior at molecular level during continuous melt granulation. Therefore, in-line Raman spectroscopy is executed during TSHMG and in situ Fourier Transform Infra-red (FTIR) during oscillatory rheological experiments. The results from the in-line Raman monitoring revealed polymorph transition of caffeine anhydrous during twin screw melt granulation with Soluplus® which is stimulated depending on the binder concentration and/or granulation temperature. A correlation was seen between the FTIR spectra obtained during the rheological temperature ramp and the in-line collected Raman spectra during the melt granulation runs. The polymorphic conversion of caffeine anhydrous could be detected in the same temperature range with both techniques, proving the comparability of plate-plate rheometry and hot melt granulation (HMG) for this case with the used parameter settings. Process simulation using rheology combined with in situ FTIR seems a promising approach to increase process understanding and to facilitate binder and parameter selection for

  7. Effects of Twin-screw Extrusion on the Color Properties of Lentinus edodes's Fiber%双螺杆挤压对香菇膳食纤维色泽的影响

    Institute of Scientific and Technical Information of China (English)

    周建勇

    2001-01-01

    Lentinus edodes's fiber was extruded using a twin-screw extruderClextral BC45. Response surface methodology was used to investigate the effects of various operation variables (screw speed,barrel temperature,feed moisture) on the extrudate's color properties, which were determined by L、A、B value. Generally, The L value was lower and A value was higher in the extrudates than those of the raw material (the control sample).The B value was between the control and the extrudates. The lowest changes in L、A and E value were occurred at the highest screw speed,lowest barrel temperature and highest feed moisture.%香菇膳食纤维采用双螺杆挤压机进行挤压处理.通过响应面分析方法对不同操作变量(螺杆转速、套筒温度、喂料水分)对产品色泽(以L、A、B值表示)的影响进行了探讨.总体而言,挤压处理使其L值低于原料组(对照组),而A值高于原料组,B值介于对照组及挤压组之间,在高螺杆转速、低套筒温度、高喂料水分操作条件下L、A及E值变化最小.

  8. EVALUATION OF PULP AND PAPER MAKING CHARACTERISTICS OF RICE STEM FIBERS PREPARED BY TWIN-SCREW EXTRUDER PULPING

    Directory of Open Access Journals (Sweden)

    Alireza Talebizadeh

    2010-06-01

    Full Text Available Twin-screw extrusion pulping is a new approach to the manufacture of pulp for paper production, designed for non-wood feedstocks. In this research, the production of pulp from rice stem with a newly fabricated twin-screw extruder was investigated. Extrusion pulping of rice stem was conducted following a central composite design using a two-level factorial plan involving three process variables (pretreatment NaOH concentration: 0.4, 0.8, 1.2%; extrusion temperature: 40, 60, 80 oC; and extruder rotational speed: 55, 70, 85 rpm. Responses of pulp and handsheets properties to the process variables were analyzed using statistical software (MINITAB 15. As the results show, pulping of rice stem fiber can be done at a relatively short pretreatment time about 4 hours and a low NaOH concentration about 0.8% by twin-screw extruder with limit extrusion temperature of about 80 oC and extruder rotational speed about 85 rpm. The effect of pretreatment solvent, NaOH, is greatly enhanced by increases in the extrusion temperature. Analysis of the results revealed that this process has suitable potential to be used to obtain a pulp with yields approximately equivalent to neutral sulfite semi-chemical pulping at fixed kappa number, which is applicable for fluting paper and linerboard production.

  9. Flow of Chemically Reactive non-Newtonian Fluids in Twin-Screw Extruders

    Science.gov (United States)

    Zhu, Weimin; Jaluria, Yogesh

    1998-11-01

    Many applications of twin-screw extruders are found in the processing of food, plastics, pharmaceutical materials and other highly viscous materials. In reactive extrusion, complex interactions in which the flow pattern, and the heat and mass transfer are affected by viscous dissipation, reaction energy, convection, residence time distribution and rheology of the materials may occur. The fluid flow, heat transfer and chemical reactions in a fully intermeshing, corotating and self wiping twin screw extruder were investigated numerically by using the finite volume method. The screw channel of a twin screw extruder are approximated as translation (parabolic) domain and intermeshing (elliptic) domain. The full governing equations were solved to determine the velocity components in the three coordinate directions. The energy equation is coupled with the equations of motion through viscosity. The Residence Time Distribution (RTD), was obtained by using a particle tracking method. The flow field, temperature field, pressure as well as RTD and chemical conversion were obtained by numerical simulation and the results yielded agreement with experimental measurements and expected physical characteristic of the process.

  10. Raw material changes and their processing parameters in an extrusion cooking process

    DEFF Research Database (Denmark)

    Cheng, Hongyuan; Friis, Alan

    In this work, the effects of raw material and process parameters on product expansion in a fish feed extrusion process were investigated. Four different recipes were studied with a pilot-scale twin-screw co-rotating extruder according to a set of pre-defined processing conditions. In the four...

  11. Development of a Twin-Screw D-2 Extruder for the ITER Pellet Injection System

    Energy Technology Data Exchange (ETDEWEB)

    Meitner, Steven J [ORNL; Baylor, Larry R [ORNL; Carbajo, Juan J [ORNL; Combs, Stephen Kirk [ORNL; Fehling, Dan T [ORNL; Foust, Charles R [ORNL; McFee, Marshall T [ORNL; McGill, James M [ORNL; Rasmussen, David A [ORNL; Sitterson, R G [ORNL; Sparks, Dennis O [ORNL; Qualls, A L [ORNL

    2009-07-01

    A twin-screw extruder for the ITER pellet injection system is under development at the Oak Ridge National Laboratory. The extruder will provide a stream of solid hydrogen isotopes to a secondary section, where pellets are cut and accelerated with single-stage gas gun into the plasma. A one-fifth ITER scale prototype extruder has been built to produce a continuous solid deuterium extrusion. Deuterium gas is precooled and liquefied before being introduced into the extruder. The precooler consists of a copper vessel containing liquid nitrogen surrounded by a deuterium gas filled copper coil. The liquefier is comprised of a copper cylinder connected to a Cryomech AL330 cryocooler, which is surrounded by a copper coil that the precooled deuterium flows through. The lower extruder barrel is connected to a Cryomech GB-37 cryocooler to solidify the deuterium (at approximate to 15 K) before it is forced through the extruder nozzle. A viewport located below the extruder nozzle provides a direct view of the extrusion. A camera is used to document the extrusion quality and duration. A data acquisition system records the extruder temperatures, torque, and speed, upstream, and downstream pressures. This paper will describe the prototype twin-screw extruder and initial extrusion results.

  12. Wet granulation in a twin-screw extruder: implications of screw design.

    Science.gov (United States)

    Thompson, M R; Sun, J

    2010-04-01

    Wet granulation in twin-screw extrusion machinery is an attractive technology for the continuous processing of pharmaceuticals. The performance of this machinery is integrally tied to its screw design yet little fundamental knowledge exists in this emerging field for granulation to intelligently create, troubleshoot, and scale-up such processes. This study endeavored to systematically examine the influence of different commercially available screw elements on the flow behavior and granulation mechanics of lactose monohydrate saturated at low concentration (5-12%, w/w) with an aqueous polyvinyl-pyrrolidone binder. The results of the work showed that current screw elements could be successfully incorporated into designs for wet granulation, to tailor the particle size as well as particle shape of an agglomerate product. Conveying elements for cohesive granular flows were shown to perform similar to their use in polymer processing, as effective transport units with low specific mechanical energy input. The conveying zones provided little significant change to the particle size or shape, though the degree of channel fill in these sections had a significant influence on the more energy-intensive mixing elements studied. The standard mixing elements for this machine, kneading blocks and comb mixers, were found to be effective for generating coarser particles, though their mechanisms of granulation differed significantly.

  13. Mechanistic modeling of modular co-rotating twin-screw extruders.

    Science.gov (United States)

    Eitzlmayr, Andreas; Koscher, Gerold; Reynolds, Gavin; Huang, Zhenyu; Booth, Jonathan; Shering, Philip; Khinast, Johannes

    2014-10-20

    In this study, we present a one-dimensional (1D) model of the metering zone of a modular, co-rotating twin-screw extruder for pharmaceutical hot melt extrusion (HME). The model accounts for filling ratio, pressure, melt temperature in screw channels and gaps, driving power, torque and the residence time distribution (RTD). It requires two empirical parameters for each screw element to be determined experimentally or numerically using computational fluid dynamics (CFD). The required Nusselt correlation for the heat transfer to the barrel was determined from experimental data. We present results for a fluid with a constant viscosity in comparison to literature data obtained from CFD simulations. Moreover, we show how to incorporate the rheology of a typical, non-Newtonian polymer melt, and present results in comparison to measurements. For both cases, we achieved excellent agreement. Furthermore, we present results for the RTD, based on experimental data from the literature, and found good agreement with simulations, in which the entire HME process was approximated with the metering model, assuming a constant viscosity for the polymer melt.

  14. Electrical and Thermal Properties of Twin-Screw Extruded Multiwalled Carbon Nanotube/Epoxy Composites

    Science.gov (United States)

    Karippal, Jeena Jose; Narasimha Murthy, H. N.; Rai, K. S.; Krishna, M.; Sreejith, M.

    2010-11-01

    This paper presents the experimental results of dispersing multiwalled carbon nanotubes (MWNTs) into epoxy (space grade structural adhesive) nanocomposites using co-rotating twin screw extrusion process. Two sets of specimens were prepared; set 1 with ultrasonication for predispersing MWNT before extrusion and set 2 direct dispersion of MWNT in the extruder. MWNT was loaded up to 8 vol.% in both the sets. The specimens were characterized for room temperature volume and surface resistivities as per ASTM D257 using Keithley Model 6517 and for thermal conductivity in the temperature range -50 to 150 °C as per ASTM E 1530 using Thermal Conductivity Instrument (TCI) 2022 SX211. The volume resistivity of sets 1 and 2 decreased to an extent of 1011 and 109 respectively. The surface resistivity drop was of the order of 109 for both the sets. These drops corresponded to the maximum MWNT loading of 8 vol.%. Electrical conductivity values of the specimens were fitted into the Power Law Model to evaluate the critical exponent. Both sets 1 and 2 showed increase in thermal conductivity with increase in temperature in the testing range. Thermal conductivity increased with increase in filler loading and the maximum increase was 60% at 150 °C in case of 8 vol.% MWNT nanocomposites for set 1. The corresponding value for the set 2 was 25%. Thermal conductivity values were predicted using Lewis Nielson model. DSC of the specimens showed increase in glass transition temperature with increase in filler loading. The dispersion of the nanofillers was studied using SEM and the surface morphology using AFM.

  15. Evolução da morfologia de fases de blendas PA6/AES em extrusora de dupla rosca e moldagem por injeção Evolution of phase morphology of PA6/AES blends during the twin screw extrusion and injection molding processes

    Directory of Open Access Journals (Sweden)

    Adriane Bassani

    2005-07-01

    Full Text Available A evolução da morfologia de fases em blendas não reativas e reativas de poliamida-6 com copolímero de acrilonitrila/EPDM/estireno (AES em uma extrusora de rosca dupla co-rotacional foi investigada. A evolução da morfologia de fases ao longo da extrusora de rosca dupla foi monitorada através da coleta de pequenas amostras em válvulas no barril da extrusora e caracterização por microscopia eletrônica de transmissão (MET. Foram utilizados como compatibilizantes reativos os copolímeros metacrilato de metila-co-anidrido maleico (MMA-MA e metacrilato de metila-co-metacrilato de glicidila (MMA-GMA. Os grupos anidrido maleico e epóxi nos copolímeros podem reagir com os grupos finais de cadeia da poliamida durante o processamento no estado fundido e melhorar a interação na interfase do sistema PA6/AES. A blenda PA6/AES não compatibilizada apresentou uma morfologia grosseira de fases onde a fase AES não está bem dispersa na matriz de PA6 devido à falta de interações adequadas entre os componentes da blenda. A adição do compatibilizante MMA-GMA não proporcionou boa dispersão de fases e não melhorou as propriedades mecânicas da blenda, provavelmente porque as possíveis reações no sistema são lentas e podem não ocorrer na extrusora. Por outro lado, a blenda compatibilizada com o copolímero MMA-MA apresentou uma excelente resistência ao impacto à temperatura ambiente e uma diminuição na temperatura de transição dúctil-frágil. As partículas de AES apresentam-se muito mais refinadas e sofrem uma redução significativa em seu tamanho já no início do processo de extrusão. A morfologia observada nas amostras injetadas apresentou uma boa correlação com as propriedades mecânicas obtidas.The evolution of phase morphology in non-reactive vs reactive blends with polyamide and ethylene-propylene-diene elastomer grafted with styrene-acrylonitrile copolymer (AES in a co-rotating twin-screw extruder was investigated. The

  16. Linking granulation performance with residence time and granulation liquid distributions in twin-screw granulation: An experimental investigation

    DEFF Research Database (Denmark)

    Kumar, Ashish; Alakarjula, Maija; Vanhoorne, Valérie

    2016-01-01

    Twin-screw granulation is a promising wet granulation technique for the continuous manufacturing of pharmaceutical solid dosage forms. A twin screw granulator displays a short residence time. Thus, the solid-liquid mixing must be achieved quickly by appropriate arrangement of transport and kneading...... elements in the granulator screw allowing the production of granules with a size distribution appropriate for tableting. The distribution of residence time and granulation liquid is governed by the field conditions (such as location and length of mixing zones) in the twin-screw granulator, thus contain...... interesting information on granulation time, mixing and resulting sub-processes such as wetting, aggregation and breakage. In this study, the impact of process (feed rate, screw speed and liquid-to-solid ratio) and equipment parameters (number of kneading discs and stagger angle) on the residence time...

  17. Asymmetric distribution in twin screw granulation.

    Science.gov (United States)

    Chan Seem, Tim; Rowson, Neil A; Gabbott, Ian; de Matas, Marcel; Reynolds, Gavin K; Ingram, Andy

    2016-09-01

    Positron Emission Particle Tracking (PEPT) was successfully employed to validate measured transverse asymmetry in material distribution in the conveying zones of a Twin Screw Granulator (TSG). Flow asymmetry was established to be a property of the granulator geometry and dependent on fill level. The liquid distribution of granules as a function of fill level was determined. High flow asymmetry at low fill level negatively affects granule nucleation leading to high variance in final uniformity. Wetting of material during nucleation was identified as a critical parameter in determining final granule uniformity and fill level is highlighted as a crucial control factor in achieving this. Flow asymmetry of dry material in conveying zones upstream of binder fluid injection leads to poor non-uniform wetting at nucleation and results in heterogeneous final product. The granule formation mechanism of 60°F kneading blocks is suggested to be primarily breakage of agglomerates formed during nucleation. Optimisation of screw configuration would be required to provide secondary growth. This work shows how fill dependent flow regimes affect granulation mechanisms.

  18. Nanoporous nanocomposite membranes via hybrid twin-screw extrusion—multijet electrospinning

    Science.gov (United States)

    Senturk-Ozer, Semra; Aktas, Seda; He, Jing; Fisher, Frank T.; Kalyon, Dilhan M.

    2017-01-01

    Non-woven nanoporous membranes of poly(caprolactone), PCL, incorporated with multi-walled carbon nanotubes, CNTs, could be fabricated via an industrially-scalable hybrid twin screw extrusion and electrospinning process. The utilization of a spinneret with multiple nozzles allowed the increase of the flow rate beyond what is possible with conventional electrospinning using a single nozzle, albeit at the expense of difficulties in the control of the thickness distributions of the nanofibrous membranes. The thickness and orientation distributions and the resulting mechanical properties of the membranes could be modified via changes in voltage, angular velocity of the collector mandrel and separation distance of the collector from the spinneret. The increases in crystallinity due to the presence of the CNTs and the preferential alignment of the nanofibers via rotation of the collecting mandrel led to increases in the tensile properties of the nanoporous membranes. The use of poly(ethylene oxide), PEO, together with PCL, followed by the dissolution of the PEO, rendered the nanofibers themselves nanoporous with typical surface porosity values of around 50% and pore sizes of about 220 nm. The demonstrated versatility of the hybrid twin screw extrusion and electrospinning process and the manipulation of mesh dimensions and properties are indicative of the applicability of the hybrid process for fabrication of nanoporous membranes for myriad diverse industrial applications ranging from water treatment to tissue engineering applications.

  19. Distribution of binder in granules produced by means of twin screw granulation.

    Science.gov (United States)

    Fonteyne, Margot; Fussell, Andrew Luke; Vercruysse, Jurgen; Vervaet, Chris; Remon, Jean Paul; Strachan, Clare; Rades, Thomas; De Beer, Thomas

    2014-02-28

    According to the quality by design principle processes may not remain black-boxes and full process understanding is required. The granule size distribution of granules produced via twin screw granulation is often found to be bimodal. The aim of this study was to gain a better understanding of binder distribution within granules produced via twin screw granulation in order to investigate if an inhomogeneous spread of binder is causing this bimodal size distribution. Theophylline-lactose-polyvinylpyrrolidone K30 (PVP) (30-67.5-2.5%, w/w) was used as a model formulation. The intra-granular distribution of PVP was evaluated by means of hyperspectral coherent anti-Stokes Raman scattering (CARS) microscopy. For the evaluated formulation, no PVP rich zones were detected when applying a lateral spatial resolution of 0.5 μm, indicating that PVP is homogenously distributed within the granules.

  20. Continuous twin screw granulation of controlled release formulations with various HPMC grades.

    Science.gov (United States)

    Vanhoorne, V; Janssens, L; Vercruysse, J; De Beer, T; Remon, J P; Vervaet, C

    2016-09-25

    HPMC is a popular matrix former to formulate tablets with extended drug release. Tablets with HPMC are preferentially produced by direct compression. However, granulation is often required prior to tableting to overcome poor flowability of the formulation. While continuous twin screw granulation has been extensively evaluated for granulation of immediate release formulations, twin screw granulation of controlled release formulations including the dissolution behavior of the formulations received little attention. Therefore, the influence of the HPMC grade (viscosity and substitution degree) and the particle size of theophylline on critical quality attributes of granules (continuously produced via twin screw granulation) and tablets was investigated in the current study. Formulations with 20 or 40% HPMC, 20% theophylline and lactose were granulated with water at fixed process parameters via twin screw granulation. The torque was influenced by the viscosity and substitution degree of HPMC, but was not a limiting factor for the granulation process. An optimal L/S ratio was selected for each formulation based on the granule size distribution. The granule size distributions were influenced by the substitution degree and concentration of HPMC and the particle size of theophylline. Raman and UV spectroscopic analysis on 8 sieve fractions of granules indicated an inhomogeneous distribution of theophylline over the size fractions. However, this phenomenon was not correlated with the hydration rate or viscosity of HPMC. Controlled release of theophylline could be obtained over 24h with release profiles close to zero-order. The release of theophylline could be tailored via selection of the substitution degree and viscosity of HPMC.

  1. Numerical Simulation of the Working Process in the Twin Screw Vacuum Pump

    Science.gov (United States)

    Lu, Yang; Fu, Yu; Guo, Bei; Fu, Lijuan; Zhang, Qingqing; Chen, Xiaole

    2017-08-01

    Twin screw vacuum pumps inherit the advantages of screw machinery, such as high reliability, stable medium conveying, small vibration, simple and compact structures, convenient operation, etc, which have been widely used in petrochemical and air industry. On the basis of previous studies, this study analyzed the geometric features of variable pitch of the twin screw vacuum pump such as the sealing line, the meshing line and the volume between teeth. The mathematical model of numerical simulation of the twin screw vacuum pump was established. The leakage paths of the working volume including the sealing line and the addendum arc were comprehensively considered. The corresponding simplified geometric model of leakage flow was built up for different leak paths and the flow coefficients were calculated. The flow coefficient value range of different leak paths was given. The results showed that the flow coefficient of different leak paths can be taken as constant value for the studied geometry. The analysis of recorded indicator diagrams showed that the increasing rotational speed can dramatically decrease the exhaust pressure and the lower rotational speed can lead to over-compression. The pressure of the isentropic process which was affected by leakage was higher than the theoretical process.

  2. Conceptual framework for model-based analysis of residence time distribution in twin-screw granulation.

    Science.gov (United States)

    Kumar, Ashish; Vercruysse, Jurgen; Vanhoorne, Valérie; Toiviainen, Maunu; Panouillot, Pierre-Emmanuel; Juuti, Mikko; Vervaet, Chris; Remon, Jean Paul; Gernaey, Krist V; De Beer, Thomas; Nopens, Ingmar

    2015-04-25

    Twin-screw granulation is a promising continuous alternative for traditional batchwise wet granulation processes. The twin-screw granulator (TSG) screws consist of transport and kneading element modules. Therefore, the granulation to a large extent is governed by the residence time distribution within each module where different granulation rate processes dominate over others. Currently, experimental data is used to determine the residence time distributions. In this study, a conceptual model based on classical chemical engineering methods is proposed to better understand and simulate the residence time distribution in a TSG. The experimental data were compared with the proposed most suitable conceptual model to estimate the parameters of the model and to analyse and predict the effects of changes in number of kneading discs and their stagger angle, screw speed and powder feed rate on residence time. The study established that the kneading block in the screw configuration acts as a plug-flow zone inside the granulator. Furthermore, it was found that a balance between the throughput force and conveying rate is required to obtain a good axial mixing inside the twin-screw granulator. Although the granulation behaviour is different for other excipients, the experimental data collection and modelling methods applied in this study are generic and can be adapted to other excipients.

  3. Flow Field Simulation and Noise Control of a Twin-Screw Engine-Driven Supercharger

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2016-01-01

    Full Text Available With the advantages of good low-speed torque capability and excellent instant response performance, twin-screw superchargers have great potential in the automobile market, but the noise of these superchargers is the main factor that discourages their use. Therefore, it is important to study their noise mechanism and methods of reducing it. This study included a transient numerical simulation of a twin-screw supercharger flow field with computational fluid dynamics software and an analysis of the pressure field of the running rotor. The results showed that overcompression was significant in the compression end stage of the supercharger, resulting in a surge in airflow to a supersonic speed and the production of shock waves that resulted in loud noise. On the basis of these findings, optimization of the supercharger is proposed, including expansion of the supercharger exhaust orifice and creation of a slot along the direction of the rotor spiral normal line at the exhaust port, so as to reduce the compression end pressure, improve the exhaust flow channel, and weaken the source of the noise. Experimental results showed that the noise level value of the improved twin-screw supercharger was significantly lower at the same speed than the original model, with an average decrease of about 5 dB (A.

  4. Continuous twin screw granulation: influence of process variables on granule and tablet quality.

    Science.gov (United States)

    Vercruysse, J; Córdoba Díaz, D; Peeters, E; Fonteyne, M; Delaet, U; Van Assche, I; De Beer, T; Remon, J P; Vervaet, C

    2012-09-01

    The aim of the current study was to screen theophylline (125 mg) tablets manufactured via twin screw granulation in order to improve process understanding and knowledge of process variables that determine granule and tablet quality. A premix of theophylline anhydrate, α-lactose monohydrate and PVP (ratio: 30/67.5/2.5,w/w) was granulated with demineralized water. Experiments were done using the high-shear wet granulation module (based on twin screw granulation) of the ConsiGma™-25 unit (a continuous tablet manufacturing system) for particle size enlargement. After drying, granules were compressed using a MODUL™ P tablet press (compression force: 10 kN, tablet diameter: 12 mm). Using a D-optimal experimental design, the effect of several process variables (throughput (10-25 kg/h), screw speed (600-950 rpm), screw configuration (number (2, 4, 6 and 12) and angle (30°, 60° and 90°) of kneading elements), barrel temperature (25-40°C) and method of binder addition (dry versus wet)) on the granulation process (torque and temperature increase in barrel wall), granule (particle size distribution, friability and flowability) and tablet (tensile strength, porosity, friability, disintegration time and dissolution) quality was evaluated. The results showed that the quality of granules and tablets can be optimized by adjusting specific process variables (number of kneading elements, barrel temperature and binder addition method) during a granulation process using a continuous twin screw granulator.

  5. 3D CFD analysis of a twin screw expander

    OpenAIRE

    Kovacevic, A.; S Rane

    2013-01-01

    Twin screw machines can be used as expanders for variety of applications. This paper describes how the performance of an oil free twin screw air expander of 3/5 lobe configuration was estimated by use of full 3D Computational Fluid Dynamics (CFD) applying a procedure similar to that used for screw compressors. The grid generator SCORG© was employed for pre-processing of the moving domains between the rotors while the stationary grids for the ports were derived from a commercial grid generator...

  6. Some physicochemical properties of dextrin produced by extrusion process

    OpenAIRE

    2014-01-01

    Dextrinization of corn starch by twin screw extruder was studied. The effect of extruder operating conditions (five different screw speeds: 35, 45, 55, 65, and 70; and three temperatures: 125, 130, and 135 °C) on some physicochemical properties of dextrin (total soluble solid, water absorption index, water solubility index, and total color difference) was investigated. Results showed that as the screw speed and temperature of extrusion were increased the water absorption index of dextrin tend...

  7. Comparison of different twin-screw extraction conditions for the production of arabinoxylans.

    Science.gov (United States)

    Jacquemin, Leslie; Mogni, Assad; Zeitoun, Rawan; Guinot, Cécile; Sablayrolles, Caroline; Saulnier, Luc; Pontalier, Pierre-Yves

    2015-02-13

    The aim of this article is to compare two different sets of optimal conditions for twin-screw extraction of xylans and define their influence on the purification steps, combining ultrafiltration and industrial chromatography. Two xylan extracts were obtained by twin-screw extrusion of straw and bran. Condition 1 used a high straw/bran ratio (equal to 6) and high sodium hydroxide content, and condition 2 used a lower straw/bran ratio (equal to 2) and low sodium hydroxide content. Arabinoxylan extraction yields are slightly higher for conditions with low straw content (5.1% versus 4.4%). Nevertheless, these recovery yields remain between 9% and 10%. Ultrafiltration is as efficient as evaporation for polysaccharide concentration, with lower energy consumption, but also demineralizes the solution. The combination of ultrafiltration and chromatography gives partial purification of the extract with a final arabinoxylan purity ranging from 16% to 26%. This is slightly higher than by direct precipitation, but limited because all the large molecules such as proteins and lignins were retained by ultrafiltration.

  8. Applied thermal pyrolysis of cogongrass in twin screw reactor

    Science.gov (United States)

    Promdee, K.; Vitidsant, T.

    2014-08-01

    Thermal pyrolysis by heat transfer model can be solved the control temperature in twin screw feeder for produce bio-oil from Cogongrass by novel continuous pyrolysis reactor. In this study, all yield were expressed on a dry and their values were taken as the average of the thermal controlled. Thermal of pyrolysis were carried out at 400-500°C. The products yield calculation showed that the liquid yield of Cogongrass by pyrolysis was higher than that solid and gas yield, as highest of 52.62%, at 500°C, and the other of liquid yield obtained from Cogongrass were 40.56, and 46.45%, at 400, and 450°C, respectively. When separate liquid phase be composed of the bio-oil was highest 37.39%, at 500°C. Indicated that biomass from Cogongrass had good received yields because of low solid yield average and gas yield and high liquid yield average. The compounds detected in bio-oil from Cogongrass showed the functional group, especially; Phenol, Phenol 2,5-dimethyl, Benzene 1-ethyl-4-methoxy, 2-Cyclopenten-1-one, 2,3-dimethyl, Benzene 1-ethyl-3-methyl.

  9. Residence time distribution in twin-screw extruders.

    NARCIS (Netherlands)

    Jager, T.

    1992-01-01

    For the twin-screw extruders used in the food industry at short time high temperature processes the knowledge of their reactor properties is incomplete for mass- and heat flow. Therefore each process change such as: scale-up or product development requires a great number of measurements before an ac

  10. Residence time distribution in twin-screw extruders

    NARCIS (Netherlands)

    Jager, T.

    1992-01-01

    For the twin-screw extruders used in the food industry at short time high temperature processes the knowledge of their reactor properties is incomplete for mass- and heat flow. Therefore each process change such as: scale-up or product development requires a great number of measurements

  11. Studies in reactive extrusion processing of biodegradable polymeric materials

    Science.gov (United States)

    Balakrishnan, Sunder

    Various reaction chemistries such as Polymerization, Polymer cross-linking and Reactive grafting were investigated in twin-screw extruders. Poly (1,4-dioxan-2-one) (PPDX) was manufactured in melt by the continuous polymerization of 1,4-dioxan-2-one (PDX) monomer in a twin-screw extruder using Aluminum tri-sec butoxide (ATSB) initiator. Good and accurate control over molecular weight was obtained by controlling the ratio of monomer to initiator. A screw configuration consisting of only conveying elements was used for the polymerization. The polymerization reaction was characterized by a monomer-polymer dynamic equilibrium, above the melting temperature of the polymer, limiting the equilibrium conversion to 78-percent. Near complete (˜100-percent) conversion was obtained on co-polymerizing PDX monomer with a few mol-percent (around 8-percent) Caprolactone (CL) monomer in a twin-screw extruder using ATSB initiator. The co-polymers exhibited improved thermal stability with reduction in glass transition temperature. The extruder was modeled as an Axial Dispersed Plug Flow Reactor for the polymerization of CL monomer using Residence Time Distribution (RTD) Analysis. The model provided a good fit to the experimental RTD and conversion data. Aliphatic and aliphatic-aromatic co-polyesters, namely Polycaprolactone (PCL) and Poly butylenes (adipate-co-terephthalate) (Ecoflex) were cross-linked in a twin-screw extruder using radical initiator to form micro-gel reinforced biodegradable polyesters. Cross-linked Ecoflex was further extrusion blended with talc to form blends suitable to be blown into films. A screw configuration consisting of conveying and kneading elements was found to be effective in dispersion of the talc particles (5--10 microns) in the polyester matrix. While the rates of crystallization increased for the talc filled polyester blends, overall crystallinity reduced. Mechanical, tear and puncture properties of films made using the talc filled polyester blends

  12. Twin Screw Extrusion of DDGS-based Aquaculture Feeds

    Science.gov (United States)

    Six isocaloric (3.65 kilocalories/gram; kcal/g), isonitrogenous (35% dry-basis; db protein), ingredient blends were prepared with 0, 17.5, 20, 22.5, 25, and 27.5% DDGS and other ingredients (soybean meal, corn, fish meal, whey, soybean oil, vitamin and mineral mix). The blends were moisture balanced...

  13. Continuous Preparation of 1:1 Haloperidol-Maleic Acid Salt by a Novel Solvent-Free Method Using a Twin Screw Melt Extruder.

    Science.gov (United States)

    Lee, Hung Lin; Vasoya, Jaydip M; Cirqueira, Marilia de Lima; Yeh, Kuan Lin; Lee, Tu; Serajuddin, Abu T M

    2017-03-10

    Salts are generally prepared by acid-base reaction in relatively large volumes of organic solvents, followed by crystallization. In this study, the potential for preparing a pharmaceutical salt between haloperidol and maleic acid by a novel solvent-free method using a twin-screw melt extruder was investigated. The pH-solubility relationship between haloperidol and maleic acid in aqueous medium was first determined, which demonstrated that 1:1 salt formation between them was feasible (pHmax 4.8; salt solubility 4.7 mg/mL). Extrusion of a 1:1 mixture of haloperidol and maleic acid at the extruder barrel temperature of 60 °C resulted in the formation of a highly crystalline salt. The effects of operating temperature and screw configuration on salt formation were also investigated, and those two were identified as key processing parameters. Salts were also prepared by solution crystallization from ethyl acetate, liquid-assisted grinding, and heat-assisted grinding and compared with those obtained by melt extrusion by using DSC, PXRD, TGA, and optical microscopy. While similar salts were obtained by all methods, both melt extrusion and solution crystallization yielded highly crystalline materials with identical enthalpies of melting. During the pH-solubility study, a salt hydrate form was also identified, which, upon heating, converted to anhydrate similar to that obtained by other methods. There were previous reports of the formation of cocrystals, but not salts, by melt extrusion. (1)H NMR and single-crystal X-ray diffraction confirmed that a salt was indeed formed in the present study. The haloperidol-maleic acid salt obtained was nonhygroscopic in the moisture sorption study and converted to the hydrate form only upon mixing with water. Thus, we are reporting for the first time a relatively simple and solvent-free twin-screw melt extrusion method for the preparation of a pharmaceutical salt that provides material comparable to that obtained by solution

  14. The optimization of Blister Disk geometry for mixing performance in co-rotating twin-screw extruder

    Science.gov (United States)

    Matsumoto, Koki; Kayamori, Natsuki; Tanaka, Tatsuya; Arao, Yoshihiko

    2015-05-01

    Extensional flow has been taken notice as the more efficient solution for improving the dispersion of nanocomposites than shear flow. One of the production processes of nanocomposites is melt extrusion with co-rotating twin-screw extruder (TSE) which is superior in terms of productivity and mixing performance. Then, we focused on "Blister Disk" which had many small holes for generating the extensional flow. However, the influences on the mixing performance by changing the geometry of Blister Disk have not been investigated as far as we know. Therefore, the objective of this study is the optimization of Blister Disk geometry (e.g. hole numbers, hole diameter and disk length) for improving the dispersion of nanocomposites. Primary, the extensional flow state was investigated at the Blister Disk with FEM analysis. Secondly, to validate the simulation results experimentally, the polypropylene reinforced multi-walled carbon nanotube (PP/CNT nanocomposite) was used as the model of nanocomposite, and the dispersion state of CNT was investigated by morphological observation. As the result of these experiments, the better dispersion state of CNT was obtained as total permeation area and shorter hole length of Blister Disk was smaller because extensional and shear stress were increased.

  15. Study on the Performance of Twin-screw Expander-compressor Used for Seawater Desalination%用于海水淡化的双螺杆膨胀压缩机热力性能研究

    Institute of Scientific and Technical Information of China (English)

    张凯; 高磊; 董冰; 邢子文

    2014-01-01

    为了研究用于机械压汽海水淡化系统的双螺杆蒸汽膨胀压缩机热力性能,建立了压缩机和膨胀机热力模型。根据已知参数求解压缩机喷水量和轴功率,膨胀机进气温度和质量流量,将计算结果与热力压汽淡化系统进行比较。通过改变压缩机进、排气压力和膨胀机进气压力,对膨胀压缩机进行变工况性能分析。结果显示,压缩机进、排气压力会对压缩机喷水量和轴功率产生不同影响;膨胀机进气压力决定进气温度的高低,且存在最佳值。%In order to study the thermal performance of twin-screw expander-compressor used for mechanical vapor compression seawater desalination system,the thermodynamic model of compressor and expander are built. Parameters like water spray mass flow rate and shaft power of the compressor,intake temperature and mass flow rate of the expander are calculated based on the known conditions,then the results are compared with thermal vapor compression seawater desalination system. Different compres-sor intake,exhaust pressure and expander intake pressure were chosen to analyze the variable condition performance of expander-compressor. The results show that the intake and exhaust pressure have different effects on shaft power and water spray mass rate of compressor;the intake pressure of the expander decides the intake temperature,and there exists an optimum value.

  16. The Comparison of Water Absorption Analysis between Counterrotating and Corotating Twin-Screw Extruders with Different Antioxidants Content in Wood Plastic Composites

    Directory of Open Access Journals (Sweden)

    Mohd Hafizuddin Ab Ghani

    2011-01-01

    Full Text Available Water absorption is a major concern for natural fibers as reinforcement in wood plastic composites (WPCs. This paper presents a study on the comparison analysis of water absorption between two types of twin-screw extruders, namely, counterrotating and corotating with presence of variable antioxidants content. Composites of mixed fibres between rice husk and saw dust with recycled high-density polyethylene (rHDPE were prepared with two different extruder machines, namely, counterrotating and corotating twin screw, respectively. The contents of matrix (30 wt% and fibres (62 wt% were mixed with additives (8 wt% and compounded using compounder before extruded using both of the machines. Samples were immersed in distilled water according to ASTM D 570-98. From the study, results indicated a significant difference among samples extruded by counterrotating and corotating twin-screw extruders. The counterrotating twin-screw extruder gives the smallest value of water absorption compared to corotating twin-screw extruder. This indicates that the types of screw play an important role in water uptake by improving the adhesion between natural fillers and the polymer matrix.

  17. Twin screw two-phase expanders in large chiller units

    Energy Technology Data Exchange (ETDEWEB)

    Smith, I.K.; Stosic, N.; Aldis, C.A.; Kovacevic, A. [City Univ., Dept. of Mechanical Engineering and Aeronautics, London (United Kingdom)

    1999-07-01

    An investigation was carried out to determine the feasibility of the use of a twin screw expander as a throttle valve replacement in a 500 ton chiller. The aim was to produce a demonstration unit with an overall machine adiabatic efficiency of not less that 70%. The efficiency target was effectively met but further analytical work is needed to predict mass flow rates reliably and hence the exact machine size required when refrigerant enters the expander as subcooled liquid. (Author)

  18. Numerical simulation of a twin screw expander for performance prediction

    Science.gov (United States)

    Papes, Iva; Degroote, Joris; Vierendeels, Jan

    2015-08-01

    With the increasing use of twin screw expanders in waste heat recovery applications, the performance prediction of these machines plays an important role. This paper presents a mathematical model for calculating the performance of a twin screw expander. From the mass and energy conservation laws, differential equations are derived which are then solved together with the appropriate Equation of State in the instantaneous control volumes. Different flow processes that occur inside the screw expander such as filling (accompanied by a substantial pressure loss) and leakage flows through the clearances are accounted for in the model. The mathematical model employs all geometrical parameters such as chamber volume, suction and leakage areas. With R245fa as working fluid, the Aungier Redlich-Kwong Equation of State has been used in order to include real gas effects. To calculate the mass flow rates through the leakage paths formed inside the screw expander, flow coefficients are considered as constant and they are derived from 3D Computational Fluid Dynamic calculations at given working conditions and applied to all other working conditions. The outcome of the mathematical model is the P-V indicator diagram which is compared to CFD results of the same twin screw expander. Since CFD calculations require significant computational time, developed mathematical model can be used for the faster performance prediction.

  19. Granulation of increasingly hydrophobic formulations using a twin screw granulator.

    Science.gov (United States)

    Yu, Shen; Reynolds, Gavin K; Huang, Zhenyu; de Matas, Marcel; Salman, Agba D

    2014-11-20

    The application of twin screw granulation in the pharmaceutical industry has generated increasing interest due to its suitability for continuous processing. However, an understanding of the impact of formulation properties such as hydrophobicity on intermediate and finished product quality has not yet been established. Hence, the current work investigated the granulation behaviour of three formulations containing increasing amounts of hydrophobic components using a Consigma™-1 twin screw granulator. Process conditions including powder feed rate, liquid to solid ratio, granulation liquid composition and screw configuration were also evaluated. The size of the wet granules was measured in order to enable exploration of granulation behaviour in isolation without confounding effects from downstream processes such as drying. The experimental observations indicated that the granulation process was not sensitive to the powder feed rate. The hydrophobicity led to heterogeneous liquid distribution and hence a relatively large proportion of un-wetted particles. Increasing numbers of kneading elements led to high shear and prolonged residence time, which acted to enhance the distribution of liquid and feeding materials. The bimodal size distributions considered to be characteristic of twin screw granulation were primarily ascribed to the breakage of relatively large granules by the kneading elements.

  20. Granule size distributions after twin-screw granulation - Do not forget the feeding systems.

    Science.gov (United States)

    Meier, R; Thommes, M; Rasenack, N; Moll, K-P; Krumme, M; Kleinebudde, P

    2016-09-01

    The aim of this study was to investigate the influence of qualitatively different powder feeder performances on resulting granule size distributions after twin-screw granulation of a highly drug loaded, hydrophobic mixture and a mannitol powder. It was shown that powder feeder related problems usually cannot be identified by trusting in the values given by the feeder. Therefore, a newly developed model for the evaluation of the performance of powder feeders was introduced and it was tried to connect this model to residence time distributions in twin-screw granulation processes. The influence of feeder performances on resulting granule size distributions varied, depending on the applied screw configuration and the used powder. Regarding the hydrophobic and highly drug loaded formulation, which was granulated at an L/S-ratio of 0.5, a pure conveying screw and a medium kneading configuration, consisting of 60° kneading blocks were negatively influenced by poor feeder settings. For optimal settings more narrow distributions could be obtained. For an extensive kneading configuration good and poor settings resulted in mono-modal granule size distributions but were differing in the overall size. Mannitol, a model substance for a liquid sensitive formulation was granulated at an L/S-ratio of 0.075. It was even more important to maintain optimal feeding as mannitol was highly affected by poor feeder performances. Even an extensive kneading configuration could not level the errors in powder feeder performance, resulting in qualitatively different granule size distributions. The results of this study demonstrate the importance of detailed knowledge about applied feeding systems to gain optimal performance in twin-screw granulation.

  1. Quantitative Assessment of Mass Flow Boundaries in Continuous Twin-screw Granulation.

    Science.gov (United States)

    Schmidt, Adrian; de Waard, Hans; Moll, Klaus-Peter; Krumme, Markus; Kleinebudde, Peter

    2016-01-01

    In pharmaceutical manufacturing, there is an increasing interest in continuous manufacturing. As an example for fast continuous processes in general of considerable complexity, this study was focussed on improving the understanding of twin-screw wet granulation. The impact of the liquid-to-solid (L/S) mass flow ratio on product quality (granules) as well as on downstream process operations (tableting) was investigated in detail. Initially two methods were used to define L/S ratio boundaries for the granulation regime in twin-screw wet granulation. It was shown that the first method, which is based on measuring the wet granule mass flow variation, can be used to define the upper L/S ratio boundary of the granulation regime. The second method, based on measuring the granule size distribution, can be used to define the lower L/S ratio boundary of the regime. Using these methods, the granulation regime for different formulations could be established. This information was then used to show that the formulation could be optimised such that the process is more robust (i.e. wider L/S ratio boundaries for the granulation regime). Also it could be used to optimise the formulation considering further downstream processing such as drying (using as little water as possible to reduce drying efforts) or tableting (obtain granules with optimised tableting properties). Preferably, the process should be performed close to the lower L/S ratio boundary of the granulation regime. In summary, these tools enabled the quantitative establishment of granulation regime boundaries in a twin-screw wet granulation process and can be used to optimise formulation and to create a robust process. Analogies to other continuous processes in completely different applications can be conceived.

  2. Linking granulation performance with residence time and granulation liquid distributions in twin-screw granulation: An experimental investigation.

    Science.gov (United States)

    Kumar, Ashish; Alakarjula, Maija; Vanhoorne, Valérie; Toiviainen, Maunu; De Leersnyder, Fien; Vercruysse, Jurgen; Juuti, Mikko; Ketolainen, Jarkko; Vervaet, Chris; Remon, Jean Paul; Gernaey, Krist V; De Beer, Thomas; Nopens, Ingmar

    2016-07-30

    Twin-screw granulation is a promising wet granulation technique for the continuous manufacturing of pharmaceutical solid dosage forms. A twin screw granulator displays a short residence time. Thus, the solid-liquid mixing must be achieved quickly by appropriate arrangement of transport and kneading elements in the granulator screw allowing the production of granules with a size distribution appropriate for tableting. The distribution of residence time and granulation liquid is governed by the field conditions (such as location and length of mixing zones) in the twin-screw granulator, thus contain interesting information on granulation time, mixing and resulting sub-processes such as wetting, aggregation and breakage. In this study, the impact of process (feed rate, screw speed and liquid-to-solid ratio) and equipment parameters (number of kneading discs and stagger angle) on the residence time (distribution), the granulation liquid-powder mixing and the resulting granule size distributions during twin-screw granulation were investigated. Residence time and axial mixing data was extracted from tracer maps and the solid-liquid mixing was quantified from moisture maps, obtained by monitoring the granules at the granulator outlet using near infra-red chemical imaging (NIR-CI). The granule size distribution was measured using the sieving method. An increasing screw speed dominantly reduced the mean residence time. Interaction of material throughput with the screw speed and with the number of kneading discs led to most variation in the studied responses including residence time and mixing capacity. At a high screw speed, granulation yield improved due to high axial mixing. However, increasing material throughput quickly lowers the yield due to insufficient mixing of liquid and powder. Moreover, increasing liquid-to-solid ratio resulted in more oversized granules, and the fraction of oversized granules further increased at higher throughput. Although an increasing number

  3. Improved tabletability after a polymorphic transition of delta-mannitol during twin screw granulation.

    Science.gov (United States)

    Vanhoorne, V; Bekaert, B; Peeters, E; De Beer, T; Remon, J-P; Vervaet, C

    2016-06-15

    In most formulations processed via continuous twin screw granulation microcrystalline cellulose (MCC) and/or lactose are used as excipients, but mannitol is also a preferred excipient for wet granulation and tableting due to its non-hygroscopicity and inertness. Therefore, the aim of the current study was to investigate the influence of process parameters on critical quality attributes of granules (moisture content, solid state, morphology, size distribution, specific surface area, friability, flowability and hygroscopicity) and tablets (tensile strength and friability) after twin screw granulation of δ-mannitol. The δ-polymorph was selected since a moisture-induced transformation to β-mannitol was observed during batch wet granulation, which exhibited a unique morphology with a large surface area and improved tabletability. A full factorial experimental design was performed, varying screw speed (400-900rpm), granulation temperature (25-40°C), number of kneading elements (6 or 12) and liquid-to-solid (L/S) ratio, on the granulation unit of a ConsiGma™-25 line (a continuous powder-to-tablet manufacturing system). After tray drying the granules were milled and tableted. The results showed that the polymorphic transition from δ- to β-mannitol also occurred during twin screw granulation, although the residence time and L/S ratios were much lower in continuous twin screw granulation compared to batch processing. However, the polymorphic transition was not complete in all experiments and depended on the L/S ratio, screw speed and number of kneading elements. Nevertheless all granules exhibited the unique morphology linked to the polymorphic transition and had a superior tabletability compared to granules produced with β-mannitol as starting material. This was attributed to enhanced plastic deformation of the granules manufactured using δ-mannitol as starting material. In addition, it was concluded that mannitol was granulated via a different mechanism than

  4. Model-based analysis of a twin-screw wet granulation system for continuous solid dosage manufacturing

    DEFF Research Database (Denmark)

    Kumar, Ashish; Vercruysse, Jurgen; Mortier, Severine T. F. C.

    2016-01-01

    Implementation of twin-screw granulation in a continuous from-powder-to-tablet manufacturing line requires process knowledge development. This is often pursued by application of mechanistic models incorporating the underlying mechanisms. In this study, granulation mechanisms considered...... the granulator under certain process conditions. Such a physical separation between the granulation regimes is promising for future design and advanced control of the continuous granulation process. (C) 2016 Elsevier Ltd. All rights reserved....

  5. Visualization and understanding of the granulation liquid mixing and distribution during continuous twin screw granulation using NIR chemical imaging.

    Science.gov (United States)

    Vercruysse, Jurgen; Toiviainen, Maunu; Fonteyne, Margot; Helkimo, Niko; Ketolainen, Jarkko; Juuti, Mikko; Delaet, Urbain; Van Assche, Ivo; Remon, Jean Paul; Vervaet, Chris; De Beer, Thomas

    2014-04-01

    Over the last decade, there has been increased interest in the application of twin screw granulation as a continuous wet granulation technique for pharmaceutical drug formulations. However, the mixing of granulation liquid and powder material during the short residence time inside the screw chamber and the atypical particle size distribution (PSD) of granules produced by twin screw granulation is not yet fully understood. Therefore, this study aims at visualizing the granulation liquid mixing and distribution during continuous twin screw granulation using NIR chemical imaging. In first instance, the residence time of material inside the barrel was investigated as function of screw speed and moisture content followed by the visualization of the granulation liquid distribution as function of different formulation and process parameters (liquid feed rate, liquid addition method, screw configuration, moisture content and barrel filling degree). The link between moisture uniformity and granule size distributions was also studied. For residence time analysis, increased screw speed and lower moisture content resulted to a shorter mean residence time and narrower residence time distribution. Besides, the distribution of granulation liquid was more homogenous at higher moisture content and with more kneading zones on the granulator screws. After optimization of the screw configuration, a two-level full factorial experimental design was performed to evaluate the influence of moisture content, screw speed and powder feed rate on the mixing efficiency of the powder and liquid phase. From these results, it was concluded that only increasing the moisture content significantly improved the granulation liquid distribution. This study demonstrates that NIR chemical imaging is a fast and adequate measurement tool for allowing process visualization and hence for providing better process understanding of a continuous twin screw granulation system.

  6. Performance Characteristics of a 4 × 6 Oil-Free Twin-Screw Compressor

    Directory of Open Access Journals (Sweden)

    Sun-Seok Byeon

    2017-07-01

    Full Text Available The screw compressor in the early stage of development is generally known as the oil-injection type. However, escalating environmental problems and advances in electronic components have spurred continuous R & D to minimize the oil content in compressed air. The oil-free twin-screw compressor is continuously compressed by inner volumetric change between rotors and casing. For this reason, in order to predict the overall performance of the screw compressor at the early stage of the design process, industry still relies on the empirical method. However, it is difficult using the existing empirical method to gain more information of the inner fluid flow of the twin-screw compressor. Flow simulation techniques using CFD are required. This study presents applications of a recently proposed overset grid method to the solution of the flow around a moving boundary. In order to analyze the performance of a 4 × 6 oil-free screw compressor, the 3-D, unsteady and compressible flow fields were numerically calculated with a shear stress transport (SST turbulence model, and implemented by the commercial software, Star-CCM+. The pressure distributions were calculated and graphically depicted. Results also showed that the volumetric and adiabatic efficiencies of the screw compressor measured by the experiments were 78% and 71%, respectively.

  7. "Rolling" phenomenon in twin screw granulation with controlled-release excipients.

    Science.gov (United States)

    Thompson, M R; O'Donnell, K P

    2015-03-01

    The developed knowledge regarding use of twin screw granulators for continuous wet granulation has been primarily limited to immediate release formulations in the literature. The present study highlights an issue previously unreported for wet granulation with twin screw extruders when using formulations containing controlled-release (CR) excipients. Long (3-10 mm), twisted noodle-like granules can be produced in the presence of these excipients that are difficult to control and are anticipated to create complications in downstream unit operations to the granulator. Working with two different CR excipients, METHOCEL™ K4M and Kollidon® SR, each blended at different ratios with a mixture of 80% α-lactose monohydrate/20% microcrystalline cellulose, these unique particles were found to be produced in the conveying elements of the extruder, arising from a rolling action at the top of the screw flights. The CR excipients adhesively strengthen the wetted mass, forming this undesired granule shape such that they persisted to the exit of the machine; the shape appeared most strongly affected by screw speed, producing particles of higher aspect ratio as speed was increased. Adjusting the concentration of these CR excipients in the formulation, the flow rate or the type of compression element used in the screws proved ineffective in controlling the problem. Rather, a re-design of the extruder screws was required to prevent generation of these extended-form granules.

  8. Impact of screw configuration on the particle size distribution of granules produced by twin screw granulation.

    Science.gov (United States)

    Vercruysse, J; Burggraeve, A; Fonteyne, M; Cappuyns, P; Delaet, U; Van Assche, I; De Beer, T; Remon, J P; Vervaet, C

    2015-02-01

    Twin screw granulation (TSG) has been reported by different research groups as an attractive technology for continuous wet granulation. However, in contrast to fluidized bed granulation, granules produced via this technique typically have a wide and multimodal particle size distribution (PSD), resulting in suboptimal flow properties. The aim of the current study was to evaluate the impact of granulator screw configuration on the PSD of granules produced by TSG. Experiments were performed using a 25 mm co-rotating twin screw granulator, being part of the ConsiGma™-25 system (a fully continuous from-powder-to-tablet manufacturing line from GEA Pharma Systems). Besides the screw elements conventionally used for TSG (conveying and kneading elements), alternative designs of screw elements (tooth-mixing-elements (TME), screw mixing elements (SME) and cutters) were investigated using an α-lactose monohydrate formulation granulated with distilled water. Granulation with only conveying elements resulted in wide and multimodal PSD. Using kneading elements, the width of the PSD could be partially narrowed and the liquid distribution was more homogeneous. However, still a significant fraction of oversized agglomerates was obtained. Implementing additional kneading elements or cutters in the final section of the screw configuration was not beneficial. Furthermore, granulation with only TME or SME had limited impact on the width of the PSD. Promising results were obtained by combining kneading elements with SME, as for these configurations the PSD was narrower and shifted to the size fractions suitable for tableting.

  9. Pyrolysis of cassava rhizome in a counter-rotating twin screw reactor unit.

    Science.gov (United States)

    Sirijanusorn, Somsak; Sriprateep, Keartisak; Pattiya, Adisak

    2013-07-01

    A counter-rotating twin screw reactor unit was investigated for its behaviour in the pyrolysis of cassava rhizome biomass. Several parameters such as pyrolysis temperature in the range of 500-700°C, biomass particle size of twin screw reactor was relatively low, whereas the solids content was relatively high, compared to some other reactor configurations.

  10. Investigating the Use of Polymeric Binders in Twin Screw Melt Granulation Process for Improving Compactibility of Drugs.

    Science.gov (United States)

    Batra, Amol; Desai, Dipen; Serajuddin, Abu T M

    2017-01-01

    Traditionally, the melt granulation for pharmaceutical products was performed at low temperature (twin screw extruder where the processing temperature could be increased to as high as 180°C and polymers with high Tg could be used as binders. In this study, different polymeric binders were screened for their suitability in improving compactibility of 2 drugs, metformin hydrochloride and acetaminophen, by twin screw melt granulation. Processing temperatures for the 2 drugs were set at 180°C and 130°C, respectively. Screw configuration, screw speed, and feed rate were optimized such that all polymeric binders used produced granules. Several hydroxypropyl cellulose, hydroxypropyl methylcellulose, polyvinylpyrrolidone, and methacrylate-based polymers, including Klucel(®) EXF, Eudragit(®) EPO, and Soluplus(®), demonstrated good tablet tensile strength (>2 MPa) when granules were produced using only 10% wt/wt polymer concentration. Certain polymers provided acceptable compactibility even at 5% wt/wt. Thus, twin screw melt granulation process may be used with different polymers at a wide range of temperature. Due to low excipient concentration, this granulation method is especially suitable for high-dose tablets.

  11. Impact of implant composition of twin-screw extruded lipid implants on the release behavior.

    Science.gov (United States)

    Even, Marie-Paule; Bobbala, Sharan; Kooi, Kok Liang; Hook, Sarah; Winter, Gerhard; Engert, Julia

    2015-09-30

    The development of vaccine delivery systems that will remove or reduce the need for repeated dosing has led to the investigation of sustained release systems. In this context, the duration of antigen release is of great importance as is the requirement for concomitant adjuvant release. In this work, lipid implants consisting of cholesterol (CHOL), soybean lecithin, Dynasan 114 (D114), the model antigen ovalbumin (OVA) and the adjuvant Quil-A (QA) were produced by twin-screw extrusion. The release of antigen and adjuvant was investigated in vitro and we observed complete OVA release over a period of 7 days while QA was released in a linear fashion over a period of up to 12 days. In order to extend OVA release, lipid implants were subjected to post-extrusion curing at 45-55°C. The OVA release could be extended to up to 14 days. Furthermore the influence of the implant composition on the release of the model antigen was investigated. It was shown that the percentage of cholesterol in particular plays an important role in modulating release.

  12. In vivo investigation of twin-screw extruded lipid implants for vaccine delivery.

    Science.gov (United States)

    Even, Marie-Paule; Young, Katie; Winter, Gerhard; Hook, Sarah; Engert, Julia

    2014-07-01

    Sustained release systems have become the focus of attention in vaccine delivery as they may reduce or prevent the need for repeated dosing. In this work, lipid implants were prepared by twin-screw extrusion and investigated as vaccine delivery systems in vivo. The lipid implants consisted of cholesterol, soybean lecithin, and Dynasan 114. Ovalbumin (OVA) was employed as a model antigen and Quil-A (QA) as an adjuvant. In addition, OVA and QA loaded liposomes were prepared by the lipid-film hydration method, freeze-dried and then added to the lipid matrix prior to extrusion. Implants were administered subcutaneously and the kinetics of antigen release as well as the overall immune response stimulated were analysed by measuring CD4(+) and CD8(+) T cell proliferation, OVA-specific IgG production as well as cytokine (IFN-γ and IL4) secretion. Vaccine release from the implants was completed by 14 days. Inclusion of adjuvant into the implants was required for the generation of cellular and humoral immune responses. Inclusion of liposomes into the implant did not enhance the resulting immune responses generated.

  13. 面包果双螺杆挤压膨化的试验研究%Experimental Study on Breadfruit Twin-screw Extrusion Expanded Snacks

    Institute of Scientific and Technical Information of China (English)

    李保国; 潘忠礼; 马海乐; 郑义

    2006-01-01

    面包果是一种淀粉含量较高的水果,为开发其加工产品,利用双螺杆挤压技术,对面包果在挤压膨化过程中物料的喂入量、含水量、挤压温度和螺杆转速等对产品性能指标(如体积密度、膨胀率、吸水性、水中溶解度)以及感官特性硬度、脆度、色差变化和比机械能等进行了试验研究.并利用SAS数据统计软件,对试验数据进行了回归分析,得到了较优的回归模型.利用回归模型,分析了挤压因素对产品物理化学特性的影响,为面包果挤压膨化食品的开发提供参考.

  14. Blend uniformity evaluation during continuous mixing in a twin screw granulator by in-line NIR using a moving F-test.

    Science.gov (United States)

    Fonteyne, Margot; Vercruysse, Jurgen; De Leersnyder, Fien; Besseling, Rut; Gerich, Ad; Oostra, Wim; Remon, Jean Paul; Vervaet, Chris; De Beer, Thomas

    2016-09-07

    This study focuses on the twin screw granulator of a continuous from-powder-to-tablet production line. Whereas powder dosing into the granulation unit is possible from a container of preblended material, a truly continuous process uses several feeders (each one dosing an individual ingredient) and relies on a continuous blending step prior to granulation. The aim of the current study was to investigate the in-line blending capacity of this twin screw granulator, equipped with conveying elements only. The feasibility of in-line NIR (SentroPAT, Sentronic GmbH, Dresden, Germany) spectroscopy for evaluating the blend uniformity of powders after the granulator was tested. Anhydrous theophylline was used as a tracer molecule and was blended with lactose monohydrate. Theophylline and lactose were both fed from a different feeder into the twin screw granulator barrel. Both homogeneous mixtures and mixing experiments with induced errors were investigated. The in-line spectroscopic analyses showed that the twin screw granulator is a useful tool for in-line blending in different conditions. The blend homogeneity was evaluated by means of a novel statistical method being the moving F-test method in which the variance between two blocks of collected NIR spectra is evaluated. The α- and β-error of the moving F-test are controlled by using the appropriate block size of spectra. The moving F-test method showed to be an appropriate calibration and maintenance free method for blend homogeneity evaluation during continuous mixing.

  15. Rotor clearance design and evaluation for an oil injected twin screw compressor

    Science.gov (United States)

    Buckney, D.; Kovacevic, A.; Stosic, N.

    2015-08-01

    Designing twin screw compressors to safely operate at higher than normal temperatures poses a challenge as the compressor must accommodate larger peak thermal distortions while ideally maintaining efficiency at nominal operating conditions. This paper will present a case study of an oil injected compressor tested at elevated discharge temperatures with original and revised clearances. The local thermal distortions occurring within the compressor during operation were estimated using a procedure developed by the authors - thermodynamic results from a chamber model were used to approximate component temperature distributions that are then used to predict possible thermal distortions and the resulting affect on clearance gaps. The original and revised clearance designs are evaluated and performance penalties incurred due to the modifications are discussed.

  16. Examining drug hydrophobicity in continuous wet granulation within a twin screw extruder.

    Science.gov (United States)

    Li, H; Thompson, M R; O'Donnell, K P

    2015-12-30

    The influence of active pharmaceutical ingredient (API) hydrophobicity on continuous wet granulation was studied in twin screw granulation utilizing foamed binder delivery. The APIs examined were caffeine, acetaminophen, ibuprofen and griseofulvin and the drug load was maintained constant at 15 wt%. In order to understand the impact of these APIs on the granulation process, API and binder distribution, particle size, porosity, and fracture strength were analyzed on samples collected along the screw length. It was found that the API and binder distributions were uniform along the screws regardless of the hydrophobicity of the formulation, in contrast to literature results with liquid injection. The absence of de-mixing of the hydrophobic ingredient was hypothesized to be a result of the high spread-to-soak ratio of a foamed binder that 'cages' those particles within the mass of local hydrophilic solids.

  17. Mixing and transport during pharmaceutical twin-screw wet granulation: experimental analysis via chemical imaging.

    Science.gov (United States)

    Kumar, Ashish; Vercruysse, Jurgen; Toiviainen, Maunu; Panouillot, Pierre-Emmanuel; Juuti, Mikko; Vanhoorne, Valérie; Vervaet, Chris; Remon, Jean Paul; Gernaey, Krist V; De Beer, Thomas; Nopens, Ingmar

    2014-07-01

    Twin-screw granulation is a promising continuous alternative for traditional batch high shear wet granulation (HSWG). The extent of HSWG in a twin screw granulator (TSG) is greatly governed by the residence time of the granulation materials in the TSG and degree of mixing. In order to determine the residence time distribution (RTD) and mixing in TSG, mostly visual observation and particle tracking methods are used, which are either inaccurate and difficult for short RTD, or provide an RTD only for a finite number of preferential tracer paths. In this study, near infrared chemical imaging, which is more accurate and provides a complete RTD, was used. The impact of changes in material throughput (10-17 kg/h), screw speed (500-900 rpm), number of kneading discs (2-12) and stagger angle (30-90°) on the RTD and axial mixing of the material was characterised. The experimental RTD curves were used to calculate the mean residence time, mean centred variance and the Péclet number to determine the axial mixing and predominance of convective over dispersive transport. The results showed that screw speed is the most influential parameter in terms of RTD and axial mixing in the TSG and established a significant interaction between screw design parameters (number and stagger angle of kneading discs) and the process parameters (material throughput and number of kneading discs). The results of the study will allow the development and validation of a transport model capable of predicting the RTD and macro-mixing in the TSG. These can later be coupled with a population balance model in order to predict granulation yields in a TSG more accurately.

  18. Encapsulation of liquids using a counter rotating twin screw extruder.

    Science.gov (United States)

    Tackenberg, Markus W; Krauss, Ralph; Marmann, Andreas; Thommes, Markus; Schuchmann, Heike P; Kleinebudde, Peter

    2015-01-01

    Until now extrusion is not applied for pharmaceutical encapsulation processes, whereas extrusion is widely used for encapsulation of flavours within food applications. Based on previous mixing studies, a hot melt counter-rotating extrusion process for encapsulation of liquid active pharmaceutical ingredients (APIs) was investigated. The mixing ratio of maltodextrin to sucrose as matrix material was adapted in first extrusion trials. Then the number of die holes was investigated to decrease expansion and agglutination of extrudates to a minimum. At a screw speed of 180 min(-1) the product temperature was decreased below 142 °C, resulting in extrudates of cylindrical shape with a crystalline content of 9-16%. Volatile orange terpenes and the nonvolatile α-tocopherol were chosen as model APIs. Design of experiments were performed to investigate the influences of barrel temperature, powder feed rate, and API content on the API retentions. A maximum of 9.2% α-tocopherol was encapsulated, while the orange terpene encapsulation rate decreased to 6.0% due to evaporation after leaving the die. During 12 weeks of storage re-crystallization of sucrose occurred; however, the encapsulated orange terpene amount remained unchanged.

  19. Encapsulation of orange terpenes investigating a plasticisation extrusion process.

    Science.gov (United States)

    Tackenberg, Markus W; Krauss, Ralph; Schuchmann, Heike P; Kleinebudde, Peter

    2015-01-01

    Extrusion is widely used for flavour encapsulation. However, there is a lack of process understanding. This study is aimed at improving the understanding of a counter rotating twin screw extrusion process. Orange terpenes as model flavour, maltodextrin and sucrose as matrix materials, and a water feed rate between 4.0% and 5.7% were applied. Product temperatures < 80 °C and specific mechanical energy inputs <260 Wh/kg resulted. Amorphous and partly crystalline samples were obtained. The loss of crystalline sucrose was linked to a dissolution process of the sugar in the available water amount. Melting of the excipients did not arise, resulting in a plasticisation extrusion process. Maximally 67% of the flavour was retained (corresponding to a 4.1% product flavour load). The flavour loss correlated with insufficient mixing during the process and flavour evaporation after extrusion. Based on these results, recommendations for an improved encapsulation process are given.

  20. Comparison of organic rankine cycle systems under varying conditions using turbine and twin-screw expanders

    OpenAIRE

    Read, M. G.; Smith, I K; Stosic, N.; Kovacevic, A.

    2016-01-01

    A multi-variable optimization program has been developed to investigate the performance of Organic Rankine Cycles (ORCs) for low temperature heat recovery applications using both turbine and twin-screw expanders when account is taken of performance variation due to changes in ambient conditions. The cycle simulation contains thermodynamic models of both types of expander. In the case of the twin-screw machine, the methods used to match the operation of the expander to the requirements of the ...

  1. Residence time and conversion in the extrusion of chemically reactive materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, W.; Jaluria, Y.

    1999-07-01

    Extrusion is one of the most versatile and energy-efficient processes for the manufacture of polymer products, including food, pharmaceuticals and plastics. Many functions including mixing, cooking and chemical reaction can be performed in an extruder. Here, twin-screw extruders offer improved control of the residence time distribution (RTD) and mixing in materials such as plastics, rubber and food. Based on the flow and the heat transfer characteristics obtained for a self-wiping, co-rotating twin-screw extruder, the residence time and chemical reaction are studied by tracking the particles. For normally starve-fed twin-screw extruders, the length of the completely filled section is calculated as function of the process variables using the coupling of the flow with the die. With a model of the solid conveying section, the RTD for the whole extruder is calculated for corn meal at different screw speeds and flow rates. The calculated variation of RTD with the screw speed and the flow rate yields good agreement with observations from many experiments. The variation of the fully filled section length, chemical conversion and mixing effectiveness are also obtained under different operation conditions. Most of the results are in qualitative agreement with experimental results and may be used as guidelines for extruder design and determination of optimal operating condition.

  2. Study of extrusion behaviour and porridge making characteristics of wheat and guava blends.

    Science.gov (United States)

    Gandhi, Neeraj; Singh, Baljit

    2015-05-01

    Extrusion cooking studies were carried out with a view to develop an instant porridge from wheat grits and guava pulp at different levels from 10 to 50 %. The mixtures were dried to bring down the moisture content to 12, 15 or 18 % and processed using twin screw extruder. The properties of extrudates (expansion ratio and density) and porridge (water absorption index, water solubility index and sensory quality) were studied. Increase in feed moisture content and guava pulp level resulted in the decrease in expansion ratio and increase in density of the extrudates. Water absorption index (WAI) increased and water solubility index (WSI) decreased with increase in feed moisture content. With increase in level of pulp, WAI decreased and WSI increased. Highly acceptable porridge was obtained at 15 % feed moisture content and 20 and 30 % guava pulp. To the samples with selected feed moisture and pulp levels, sugar was added at 20, 25 and 30 % levels to prepare the final product. Sugar level of 30 % was found out to be most acceptable. Fruit porridge stored in LDPE and aluminum laminate pouches at ambient temperature remained acceptable upto 6 months.

  3. Stearic acid and high molecular weight PEO as matrix for the highly water soluble metoprolol tartrate in continuous twin-screw melt granulation

    OpenAIRE

    Monteyne, Tinne; Adriaensens, Peter; Brouckaert, Davinia; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

    2016-01-01

    Granules with release-sustaining properties were developed by twin screw hot melt granulation (HMG) using a combination of stearic acid (SA) and high molecular weight polyethylene oxide (PEO) as matrix for a highly water soluble model drug, metoprolol tartrate (MPT). Earlier studies demonstrated that mixing molten SA and PEO resulted in hydrogen bond formation between hydroxyl groups of fatty acid molecules and ether groups in PEO chains. These molecular interactions might be beneficial in or...

  4. Effect of binders on the release rates of direct molded verapamil tablets using twin-screw extruder in melt granulation.

    Science.gov (United States)

    Tan, David Cheng Thiam; Chin, William Wei Lim; Tan, En Hui; Hong, Shiqi; Gu, Wei; Gokhale, Rajeev

    2014-03-10

    Conventional manufacturing of pharmaceutical tablets often involves single processes such as blending, granulation, milling and direct compression. A process that minimizes and incorporates all these in a single continuous step is desirable. The concept of omitting milling step followed by direct-molding of tablets utilizing a twin-screw extruder in a melt granulation process using thermoplastic binders was explored. The objective of this study was to investigate the effect of combining hydrophilic binder (HPMC K4M, PEO 1M), and hydrophobic binder (Compritol® ATO 888, Precirol® ATO 5) on the release profiles of direct-molded tablets and direct-compressed tablets from milled extrudates using a quality-by-design approach. It was identified that hydrophilic binder type and process significantly affects (p=0.005) the release profiles of verapamil. Moreover, two-way interaction analysis demonstrated that the combination of process with type of hydrophilic polymer (p=0.028) and the type of hydrophilic polymer with polymer ratio (p=0.033) significantly affected the release profiles. The formulation release kinetics correlated to Higuchi release model and the mechanism correlated to a non-Fickian release mechanism. The results of the present study indicated that direct-molded tablets with different release profiles can be manufactured without milling process and through a continuous melt granulation using twin-screw extruder with appropriate thermoplastic binder ratio.

  5. The use of twin screw extruders for feeding coal against pressures of up to 1500 PSI

    Science.gov (United States)

    Wiedmann, W.; Mack, W. A.

    1977-01-01

    Recent tests with a twin-screw, co-rotating extruder which was successfully used to convey and feed coal against pressures of up to 1500 psi are described. Intermeshing and self-wiping, co-rotating twin-screws give greatly improved conveying and pressure built-up capabilities and avoid hangup and eventual decomposition of coal particles in the screw flights. The conveying action of intermeshing, self-wiping, co-rotating extruder systems approaches that of a positive displacement pump. With this feature, it is possible to maintain very accurate control over all aspects of product conveyance in the extruder, i.e., intake, conveyance and pressure buildup.

  6. Improved corn protein (zein) extrusion processing

    Science.gov (United States)

    Melt processing using a single and twin screw extruder has been carried out on zein where extrusion temperatures were varied between 100ºC and 300ºC. In addition, melt reprocessing (up to seven times) of zein was undertaken using a single screw extruder. Differential scanning calorimetry (DSC) and t...

  7. Reactive Extrusion of Zein with Glyoxal

    Science.gov (United States)

    Cross-linked zein has been produced using glyoxal as the cross-linking reagent via reactive extrusion for the first time in a twin screw extruder using dilute sodium hydroxide as catalyst. Tri(ethylene glycol) was used as a plasticizer for various items. The extrudate was then ground and processed...

  8. Influence of filler selection on twin screw foam granulation.

    Science.gov (United States)

    Rocca, K E; Weatherley, S; Sheskey, P J; Thompson, M R

    2015-01-01

    The influence of filler selection in wet granulation was studied for the novel case where the binder is delivered as an unstable, semi-rigid aqueous foam to an extrusion process. The work primarily examined the impact of differing concentrations of microcrystalline cellulose (Avicel PH® 101) in a formulation with spray-dried α-lactose monohydrate (Flowlac® 100) in regards to wetting and granule nucleation for this relatively new technique known as continuous foam granulation. Foam stability was varied within the work to change its drainage and coarsening behavior atop these powder excipients, by use of different foamable binding agents (METHOCEL™ F4 PLV and METHOCEL™ Premium VLV) as well as by adjusting the foam quality. A static bed penetration test was first used to study the foam behavior in wetting these powders without the processing constraints of an extruder which limit possible liquid-to-solids ratios as well as introduce shear which may complicate interpretation of the mechanism. The test found that the penetration time to saturate these powders decreased as their water absorption capacity increased which in turn decreased the size of the formed nuclei. Differences in the stability of the foamed binder had minimal influence on these attributes of wetting despite its high spread-to-soak behavior. The size of granules produced by extrusion similarly demonstrated sensitivity to the increasing water absorption capacity of the filler and little dependency on foam properties. The different liquid-to-solids ratios required to granulate these different formulations inside the extruder highlighted an evolving concept of powder lubricity for continuous foam granulation.

  9. Experimental analysis of the material degradation of PET on a co-rotating twin-screw extruder for varying vacuum pressures

    Science.gov (United States)

    Herken, T.; Fecke, N.; Schöppner, V.

    2015-05-01

    Plastics, starting from inexpensive mass-produced articles to technical high-end applications, are being used in ever more areas of life. The main drivers are their flexible product properties and the resultant broad application possibilities. To be able to offer plastic products inexpensively and conserve the environment at the same time, more and more attention is being paid to plastics recycling. Polyethylene terephthalate - in short PET - is of particular significance here because of its frequent application in the film and packaging industry and its special material properties. The recycling of PET, however, can only be carried out a limited number of times because it's processing necessarily results in both thermal and mechanical stresses on the material. This is the basis for the reactions at molecular level, which result in a shortening of the molecule chains (material degradation) and exert a negative effect on the product properties. The aim of this study is to identify the factors that influence the material degradation of PET in twin-screw extrusion. To do this, various screw configurations and different speed and throughput conditions are examined in a series of experiments. Furthermore, material specimens are removed along the length of the screw in order to evaluate the influence of individual screw sections. By determining the intrinsic viscosity of the specimens, it is possible to measure the mean molecular weight and thus the material damage. Based on the test results, guidelines are drawn up for the compounding of PET so as to ensure as little damage as possible to the material.

  10. Experimental analysis of the material degradation of PET on a co-rotating twin-screw extruder for varying vacuum pressures

    Energy Technology Data Exchange (ETDEWEB)

    Herken, T.; Fecke, N.; Schöppner, V., E-mail: Tobias.Herken@ktp.uni-paderborn.de, E-mail: Nikolas.Fecke@ktp.uni-paderborn.de, E-mail: Volker.Schoeppner@ktp.uni-paderborn.de [KTP, University of Paderborn (Germany)

    2015-05-22

    Plastics, starting from inexpensive mass-produced articles to technical high-end applications, are being used in ever more areas of life. The main drivers are their flexible product properties and the resultant broad application possibilities. To be able to offer plastic products inexpensively and conserve the environment at the same time, more and more attention is being paid to plastics recycling. Polyethylene terephthalate – in short PET – is of particular significance here because of its frequent application in the film and packaging industry and its special material properties. The recycling of PET, however, can only be carried out a limited number of times because it’s processing necessarily results in both thermal and mechanical stresses on the material. This is the basis for the reactions at molecular level, which result in a shortening of the molecule chains (material degradation) and exert a negative effect on the product properties. The aim of this study is to identify the factors that influence the material degradation of PET in twin-screw extrusion. To do this, various screw configurations and different speed and throughput conditions are examined in a series of experiments. Furthermore, material specimens are removed along the length of the screw in order to evaluate the influence of individual screw sections. By determining the intrinsic viscosity of the specimens, it is possible to measure the mean molecular weight and thus the material damage. Based on the test results, guidelines are drawn up for the compounding of PET so as to ensure as little damage as possible to the material.

  11. Experimental investigation of granule size and shape dynamics in twin-screw granulation.

    Science.gov (United States)

    Kumar, Ashish; Vercruysse, Jurgen; Bellandi, Giacomo; Gernaey, Krist V; Vervaet, Chris; Remon, Jean Paul; De Beer, Thomas; Nopens, Ingmar

    2014-11-20

    A twin-screw granulator (TSG), a promising equipment for continuous high shear wet granulation (HSWG), achieves the desired level of mixing by a combination of the appropriate screw configuration and a suitable set of process settings (e.g. feed rate, screw speed, etc.), thus producing a certain granule size and shape distribution (GSSD). However, the primary sizing and shaping mechanism behind the resulting distribution is not well understood due to the opacity of the multiphase system in the granulator. This study experimentally characterised the GSSD dynamics along the TSG barrel length in order to understand the function of individual screw modules and process settings, as well as their interaction. Particle size analysis of granules collected at the outlet of the TSG suggested significant interaction between the process and screw configuration parameters influencing the heterogeneity in the GSSD. By characterising the samples collected along the screw length, a variable influence of the screw modules at different process conditions was observed. At low liquid-to-solid ratio (L/S), the first kneading module seemed to play a significant role in mixing, whereas the second kneading module was found to be more involved in reshaping the granules. At high L/S and high throughput, aggregation mainly took place in the second kneading module changing the GSSD. The results obtained from this study will be further used for the calibration and validation of a mechanistic model and, hence, support future development of a more detailed understanding of the HSWG process in a TSG.

  12. Numerical and Experimental Investigation of Pressure Losses at Suction of a Twin Screw Compressor

    Science.gov (United States)

    Arjeneh, M.; Kovacevic, A.; Rane, S.; Manolis, M.; Stosic, N.

    2015-08-01

    Rotary twin screw machines are used in the wide range of industrial applications and are capable of handling single and multiphase fluids as compressors, expanders and pumps. Concentration of liquid in the inlet flow can influence the performance of the machine significantly. Characteristics of the multiphase flow at the suction of a screw compressor depend on the local flow velocities and concentration. Local flow velocity measurements inside the screw compressors are difficult to obtain. However other flow properties such as local pressures are easier to attain. It is therefore useful to carry out experiments with local pressure variations in the suction which can be used to validate the 3D numerical Computational Fluid Dynamic (CFD) models that could help in studying the single and multiphase flow behaviour in screw compressors. This paper presents experimental efforts to measure the local pressure losses inside the suction plenum of the screw compressor. Pressure variations are measured at 23 locations in the suction port at various operating conditions and compared with 3D CFD model. The grid generator SCORGTM was used for generating numerical mesh of rotors. The flow calculations were carried out using commercial 3D solver ANSYS CFX. It was found that the local pressure changes predicted by the CFD model are in the good agreement with measured pressures. This validated the use of CFD for modelling of the single phase flows in suction of screw machines.

  13. Twin screw extruders as polymerization reactors for a free radical homo polymerization

    NARCIS (Netherlands)

    Ganzeveld, K.J.; Janssen, L.P.B.M.

    1993-01-01

    The bulk polymerization of n-butylmethacrylate was investigated in a counter-rotating twin screw extruder. It appeared that the gel effect, occurring with bulk polymerizations, affected the polymerization progress very strongly. Due to this effect the conversion of the reaction is independent of the

  14. Flow characteristics of screws and special mixing enhancers in a co-rotating twin screw extruder

    NARCIS (Netherlands)

    Brouwer, T.; Todd, D.B.; Janssen, L.P.B.M.

    2002-01-01

    The flow behavior of a Newtonian fluid through special mixing enhancers in a modular intermeshing co-rotating twin screw extruder has been examined. The mixing enhancers are slotted screws and gear mixing elements. Particular attention has been directed to drag and pressure flow characteristics and

  15. Optimization of the Extruding Operating Parameters for Chicken Mixture with Twin-Screw Extruder%双螺杆挤压鸡肉混合物工艺参数的优化

    Institute of Scientific and Technical Information of China (English)

    石彦国; 李可; 叶暾昊; 张光

    2012-01-01

    The soybean-rice-chieken-whole milk powder mixture is used as raw materials. Box-Behnken experimental design combining with response surface metho-dology was employed to study the twin-screw extrusion process parameter conditions, including material moisture content、 feeding speed、 screw speed、 the fifth district of barrel temperature on gelatinization degree. The best extruding condition is obtained: the moisture content is 23.32%, the fifth district of barrel temperature is 105℃, the screw speed is 160r/min, the feeding speed is 30r/min.%以大豆、大米、鸡肉、全脂乳粉为原料,按一定比例混合,采用Box-Behnken中心组合试验研究双螺杆挤压工艺参数.综合考察物科含水率、喂料速度、螺杆转速、温度对糊化度的影响,在此基础上对变量进行响应面分析,得出最佳挤压参数是:物料含水率23.32%,五区温度105℃,螺杆转速160 r/min,喂料速度30 r/min.

  16. A novel optical technique to characterize fiberization of textured vegetable proteins under high-moisture extrusion

    Science.gov (United States)

    Yao, Gang; Liu, Keshun; Hsieh, Fu-Hung

    2004-11-01

    There have been great interests in using twin-screw extruders under high moisture conditions to produce textured vegetable proteins. Unlike the low moisture extrusion counterpart, a product extruded under high moisture can have well-defined fiber orientation and bears a strong resemblance to muscle meat. The textural properties of such extruded products are important for consumer acceptance. In this study, we developed a novel fluorescence polarization based technique that measures the fiber formation of extruded protein products. The experimental results using our new technique showed good agreements with results obtained from visual inspection and digital imaging of the dissected samples. The new technique provides an in vivo and noninvasive approach to characterize the fiber formation of textured vegetable proteins under high moisture extrusion. It has a potential to be used as a real time monitoring tool in food extrusion studies.

  17. Development of a controlled release formulation by continuous twin screw granulation: Influence of process and formulation parameters.

    Science.gov (United States)

    Vanhoorne, V; Vanbillemont, B; Vercruysse, J; De Leersnyder, F; Gomes, P; Beer, T De; Remon, J P; Vervaet, C

    2016-05-30

    The aim of this study was to evaluate the potential of twin screw granulation for the continuous production of controlled release formulations with hydroxypropylmethylcellulose as hydrophilic matrix former. Metoprolol tartrate was included in the formulation as very water soluble model drug. A premix of metoprolol tartrate, hydroxypropylmethylcellulose and filler (ratio 20/20/60, w/w) was granulated with demineralized water via twin screw granulation. After oven drying and milling, tablets were produced on a rotary Modul™ P tablet press. A D-optimal design (29 experiments) was used to assess the influence of process (screw speed, throughput, barrel temperature and screw design) and formulation parameters (starch content of the filler) on the process (torque), granule (size distribution, shape, friability, density) and tablet (hardness, friability and dissolution) critical quality attributes. The torque was dominated by the number of kneading elements and throughput, whereas screw speed and filling degree only showed a minor influence on torque. Addition of screw mixing elements after a block of kneading elements improved the yield of the process before milling as it resulted in less oversized granules and also after milling as less fines were present. Temperature was also an important parameter to optimize as a higher temperature yielded less fines and positively influenced the aspect ratio. The shape of hydroxypropylmethylcellulose granules was comparable to that of immediate release formulations. Tensile strength and friability of tablets were not dependent on the process parameters. The use of starch as filler was not beneficial with regard to granule and tablet properties. Complete drug release was obtained after 16-20h and was independent of the design's parameters.

  18. Impact of fill-level in twin-screw granulation on critical quality attributes of granules and tablets.

    Science.gov (United States)

    Meier, Robin; Moll, Klaus-Peter; Krumme, Markus; Kleinebudde, Peter

    2017-02-15

    In a previous study a change of the fill-level in the barrel exerted a huge influence on the twin-screw granulation (TSG) process of a high drug loaded, simplified formulation. The present work investigated this influence systematically. The specific feed load (SFL) indicating the mass per revolution as surrogate parameter for the fill-level was applied and the correlation to the real volumetric fill level of an extruder could be demonstrated by a newly developed method. A design of experiments was conducted to examine the combined influence of SFL and screw speed on the process and on critical quality attributes of granules and tablets. The same formulation was granulated at constant liquid level with the same screw configuration and led to distinctively different results by only changing the fill-level and the screw speed. The power consumption of the extruder increased at higher SFLs with hardly any influence of screw speed. At low SFL the median residence time was mainly fill-level dependent and at higher SFL mainly screw speed dependent. Optimal values for the product characteristics were found at medium values for the SFL. Granule size distributions shifted from mono-modal and narrow shape to broader and even bimodal distributions of larger median granule sizes, when exceeding or falling below a certain fill-level. Deviating from the optimum fill-level, tensile strength of tablets decreased by about 25 % and disintegration times of tablets increased for more than one third. At low fill-levels, material accumulation in front of the kneading zone was detected by pressure measurements and was assumed to be responsible for the unfavored product performance. At high fill-levels, granule consolidation due to higher propensity of contact with the result of higher material temperature was accounted for inferior product performance. The fill-level was found to be an important factor in assessment and development of twin-screw granulation processes as it impacted

  19. A new scale-up approach for dispersive mixing in twin-screw compounding

    Science.gov (United States)

    Fukuda, Graeme; Bigio, David I.; Andersen, Paul; Wetzel, Mark

    2015-05-01

    Scale-up rules in polymer processing are critical in ensuring consistency in product quality and properties when transitioning from low volume laboratory mixing processes to high volume industrial compounding. The scale-up approach investigated in this study evaluates the processes with respect to dispersive mixing. Demand of polymer composites with solid additives, such as carbon microfibers and nanotubes, has become increasingly popular. Dispersive mixing breaks down particles that agglomerate, which is paramount in processing composites because solid additives tend to collect and clump. The amount of stress imparted on the material governs the degree of dispersive mixing. A methodology has been developed to characterize the Residence Stress Distribution (RSD) within a twin-screw extruder in real time through the use of polymeric stress beads. Through this technique, certain mixing scale-up rules can be analyzed. The following research investigated two different scale-up rules. The industry standard for mixing scale-up takes the ratio of outer diameters cubed to convert the volumetric flow rate from the smaller process to a flow rate appropriate in the larger machine. This procedure then resolves both operating conditions since shear rate remains constant. The second rule studied is based on percent drag flow, or the fraction of pumping potential, for different elements along the screw configuration. The percent drag flow rule aims to bring greater focus to operating conditions when scaling-up with respect to dispersive mixing. Through the use of the RSD methodology and a Design of Experiment (DOE) approach, rigorous statistical analysis was used to determine the validity between the scale-up rules of argument.

  20. Stability and repeatability of a continuous twin screw granulation and drying system.

    Science.gov (United States)

    Vercruysse, J; Delaet, U; Van Assche, I; Cappuyns, P; Arata, F; Caporicci, G; De Beer, T; Remon, J P; Vervaet, C

    2013-11-01

    The aim of this study was to investigate the process transfer of a commercially available product from the current batch fluid bed granulation and drying production method to an innovative continuously operating "from powder to tablet" production line using twin screw granulation as an intermediate granulation step. By monitoring process outcomes (torque, water temperature at the granulator jacket inlet, differential pressure over the dryer filters, and temperature mill screen) and granule and tablet quality in function of process time, the stability and repeatability during long production runs were determined. Three consecutive 5h "from powder to tablet" production runs were performed using the ConsiGma™-25 system (GEA Pharma Systems, Collette™, Wommelgem, Belgium). A premix of two active ingredients, powdered cellulose, maize starch, pregelatinized starch, and sodium starch glycolate was granulated with distilled water. After drying and milling (1000 μm and 800 rpm), granules were in-line blended with magnesium stearate and directly compressed using a Modul™ P tablet press (tablet weight: 430 mg, main compression force: 12 kN). Granule (loss on drying, particle size distribution, friability, flow) and tablet (weight uniformity, hardness, thickness, friability, content uniformity, disintegration time, and dissolution) quality was evaluated in function of process time. For each of the logged process outcomes, a stabilization period was needed to reach steady-state conditions. Slightly deviating particle size distribution and friability results for milled granules were observed during start-up due to initial layering of the mill screen. However, no deviating tablet quality was detected in function of process time. For multiple hours, granule and tablet quality was constant in function of process time. Furthermore, process data trends were highly repeatable. Consequently, the ConsiGma™-25 system can be considered as a stable and repeatable system for the

  1. Effect of Multiple Extrusions on the Impact Properties of Polypropylene/Clay Nanocomposites

    DEFF Research Database (Denmark)

    Klitkou, Rasmus; Jensen, Erik Appel; Christiansen, Jesper de Claville

    2012-01-01

    Polypropylene (PP)-based polymer nanocomposites containing organically modified montmorillonite (OMMT) with and without maleic anhydride grafted PP, were compounded by twin-screw extrusion. The extrusion process was repeated various numbers of times to increase the extruder residence time (TR) and...

  2. Development of a test rig for a helium twin-screw compressor

    Science.gov (United States)

    Wang, B. M.; Hu, Z. J.; Zhang, P.; Li, Q.

    2014-01-01

    A large helium cryogenic system is being developed for use in great science projects, such as the International Thermonuclear Experimental Reactor (ITER), Large Helical Device (LHD), and the Experimental Advanced Superconducting Tokamak (EAST). In this cryogenic system, a twin-screw compressor is a key component. Therefore, it is necessary to obtain the compressor performance. To obtain the performance characteristics, a test rig for the compressor has been built. All the important performance parameters, including adiabatic efficiency, volumetric efficiency, oil injection characteristic, and noise characteristic can be acquired with the rig when sensors are installed in the test system. With the test performance, the helium twin-screw compressor can be evaluated. Using these results, the design of the compressor can be improved.

  3. Evaluation of an in-line particle imaging tool for monitoring twin-screw granulation performance

    DEFF Research Database (Denmark)

    Kumar, Ashish; Dhondt, Jens; De Leersnyder, Fien;

    2015-01-01

    ). The volumetric size distribution obtained from the in-line measurements of the granules leaving the twin-screw granulator using the Eyecon™ camera was compared with the off-line measurements obtainedby sieving of the granule samples collected before and after the drying unit operation. For the intermediate size...... range (diameter 250–1000 μm), the Eyecon™ measurements showed to be promising as they were in agreement with off-line measurement results obtained before the drying unit. However, the image analysis algorithm and data post-processing of the Eyecon™ images for the fines and oversized ranges require......Twin-screw granulation is an emerging continuous wet granulation technique in the pharmaceutical industry due to several advantages over batch granulation. However, for the implementation of a fully continuous linein an industrial environment, in-process measurement tools are required to monitor...

  4. Two phase residence time distribution in a modified twin screw extruder

    OpenAIRE

    1999-01-01

    Biomass fractionation is performed with a modified Clextral twin-screw extruder used as a thermo-mechano-chemical reactor. This new process is firstly analyzed. Visual observations, residence time distributions, and global mass balances are used to obtain information about the process phenomena and their coupling. Residence time distributions (RTD) classical models are adopted to represent the experimental plots. The influence of continuous and discrete process parameters upon the RTD of the ...

  5. Thermodynamic Simulation on the Performance of Twin Screw Expander Applied in Geothermal Power Generation

    OpenAIRE

    Yuanqu Qi; Yuefeng Yu

    2016-01-01

    A three-dimensional (3D) geometry model of twin screw expander has been developed in this paper to measure and analyze geometric parameters such as groove volume, suction port area, and leakage area, which can be described as functions of rotation angle of male rotor. Taking the suction loss, leakage loss, and real gas effect into consideration, a thermodynamic model is developed using continuity and energy conservation equation. The developed model is verified by comparing predicted results ...

  6. Comparison of Organic Rankine Cycle Under Varying Conditions Using Turbine and Twin-Screw Expanders

    OpenAIRE

    Read, M. G.; Smith, I K; Stosic, N.

    2015-01-01

    A multi-variable optimization program has been developed to investigate the performance of Organic Rankine Cycles (ORCs) for low temperature heat recovery applications. This cycle model contains detailed thermodynamic models of the system components, and the methods used to match the operation of the expander to the requirements of the cycle are described. Two types of ORC system are considered; one containing a turbine to expand dry saturated or superheated vapour, and one with a twin-screw ...

  7. Encapsulation of Liquids Via Extrusion--A Review.

    Science.gov (United States)

    Tackenberg, Markus W; Kleinebudde, Peter

    2015-01-01

    Various encapsulation techniques are known for pharmaceutical applications. Extrusion is of minor importance. However, extrusion is used to obtain granules with encapsulate liquid active ingredients (AI) like essential oils and flavours for food applications since decades. Many of these AIs can be used for agrochemical, home care, and pharmaceutical products, too. Thus, the focus of this review is on the interdisciplinary presentation and evaluation of the available knowledge about the encapsulation process via extrusion. The desired microcapsule structure is discussed at the outset. The microcapsule is compared to the alternative glassy solid solution system, before an overview of suitable excipients is given. In the next section the development of the extrusion technique, used for encapsulation processes, is presented. Thereby, the focus is on encapsulation using twin-screw extruders. Additionally, the influence of the downstream processes on the products is discussed, too. The understanding of the physical processes during extrusion is essential for specifically adjustment of the desired product properties and thus, highlighted in this paper. Unfortunately not all processes, especially the mixing process, are well studied. Suggestions for further studies, to improve process understanding and product quality, are given, too. The last part of this review focuses on the characterization of the obtained granules, especially AI content, encapsulation efficiency, and storage stability. In conclusion, extrusion is a standard technique for flavour encapsulation, but future studies, may lead to more (pharmaceutical) applications and new products.

  8. Artificial neural network modelling of continuous wet granulation using a twin-screw extruder.

    Science.gov (United States)

    Shirazian, Saeed; Kuhs, Manuel; Darwish, Shaza; Croker, Denise; Walker, Gavin M

    2017-04-15

    Computational modelling of twin-screw granulation was conducted by using an artificial neural network (ANN) approach. Various ANN configurations were considered with changing hidden layers, nodes and activation functions to determine the optimum model for the prediction of the process. The neural networks were trained using experimental data obtained for granulation of pure microcrystalline cellulose using a 12mm twin-screw extruder. The experimental data were obtained for various liquid binder (water) to solid ratios, screw speeds, material throughputs, and screw configurations. The granulate particle size distribution, represented by d-values (d10, d50, d90) were considered the response in the experiments and the ANN model. Linear and non-linear activation functions were taken into account in the simulations and more accurate results were obtained for non-linear function in terms of prediction. Moreover, 2 hidden layers with 2 nodes per layer and 3-Fold cross-validation method gave the most accurate simulation. The results revealed that the developed ANN model is capable of predicting granule size distribution in high-shear twin-screw granulation with a high accuracy in different conditions, and can be used for implementation of model predictive control in continuous pharmaceutical manufacturing.

  9. Extrusion cooking with glucose supplementation reduced fumonisin concentrations and toxicity

    Science.gov (United States)

    Extrusion cooking involves forcing material through a heated barrel under high pressure using one (single-screw configuration) or two (twin-screw configuration) augers. We previously demonstrated (Bullerman et al., Journal of Agricultural and Food Chemistry 56:2400-2405, 2008; Voss et al., Journal o...

  10. Effect of twin-screw extrusion parameters on mechanical hardness of direct-expanded extrudates

    Indian Academy of Sciences (India)

    M Brnčić; B Tripalo; D Ježek; D Semenski; N Drvar; M Ukrainczyk

    2006-10-01

    Mechanical properties of cereal (starch-based) extrudates are perceived by the final consumer as criteria of quality. We investigate one of the important characteristics of extrudates, mechanical hardness, which is one of the main texture parameters. Texture quality has an influence on taste sensory evaluation, and thus on the acceptability of the product. Characteristics that have great influence on acceptability are crispness, elasticity, hardness and softness. These attributes are narrowly related to, and affected by, the process parameters. A 2-level–4-factor factorial experimental design was used to investigate the influence of temperature of expansion, screw speed, feed moisture content and feed rate, and their interactions, on the mechanical hardness of extrudates. Feed moisture content, screw speed and temperature are found to influence, while feed rate does not have significant effect on extrudate hardness. Mechanical properties of specimens were measured by means of compression testing, based on the concept of nominal stress, using a universal testing machine and special grips that were constructed for this purpose.

  11. Fundamentals of twin-screw extrusion polymer melting: Common pitfalls and how to avoid them

    Science.gov (United States)

    Andersen, Paul

    2015-05-01

    The process for compounding engineered polymer formulations is comprised of several unit operations. These typically include, but are not limited to: feedstock introduction, polymer melt-mixing, distributive/dispersive mixing of minerals/fibers, removal of volatiles, and pressurization for discharge. While each unit operation has an impact on process productivity and the quality of the finished product, polymer melt-mixing has a significantly greater impact than the others. First, it consumes 50, 60 or higher percent of the total system energy. Second, it generates the highest radial as well as particle-particle interactive pressure of any unit operation. Third, the negative impact on the process of any design flaws in the melt-mixing configuration is transmitted downstream to all subsequent unit operations. For example, a melt-mixing design that is too intense may degrade the polymer while one that is too weak may result in excessive breakage of glass fiber being fed downstream due to the polymer solidifying on the glass fiber and subsequently being re-melted. Another example of the impact of an incorrect melt-mixing configuration would be excessive abrasive wear. Adhesive wear is also possible as well as deformation on both barrel wall and screw elements due to high radial forces. Additionally, non-melting material present during the melt-mixing process could be compacted into "briquettes" by the high radial pressure and would have to be dispersed by subsequent downstream unit operations. Other potential issues associated with a non-optimal melting section are pre-mature and incomplete melting. The former is more of a concern with melting of powder feed stock while the latter is more probable with feed stock comprised of a broad range of particle sizes. However, the consequence of both is to convey unmolten polymer beyond the melting section. While this may not be perceived as a significant issue for most processes, it is an issue if the sole purpose of the process is to uniformly melt the feedstock. This is case for powder to pellet conversion of polyolefins and melt spinning of mono-filament.

  12. Formulation and development of pH-independent/dependent sustained release matrix tablets of ondansetron HCl by a continuous twin-screw melt granulation process.

    Science.gov (United States)

    Patil, Hemlata; Tiwari, Roshan V; Upadhye, Sampada B; Vladyka, Ronald S; Repka, Michael A

    2015-12-30

    The objective of the present study was to develop pH-independent/dependent sustained release (SR) tablets of ondansetron HCl dihydrate (OND), a selective 5-HT3 receptor antagonist that is used for prevention of nausea and vomiting caused by chemotherapy, radiotherapy and postoperative treatment. The challenge with the OND API is its pH-dependent solubility and relatively short elimination half-life. Therefore, investigations were made to solve these problems in the current study. Formulations were prepared using stearic acid as a binding agent via a melt granulation process in a twin-screw extruder. The micro-environmental pH of the tablet was manipulated by the addition of fumaric acid to enhance the solubility and release of OND from the tablet. The in vitro release study demonstrated sustained release for 24h with 90% of drug release in formulations using stearic acid in combination with ethyl cellulose, whereas 100% drug release in 8h for stearic acid-hydroxypropylcellulose matrices. The formulation release kinetics was correlated to the Higuchi diffusion model and a non-Fickian drug release mechanism. The results of the present study demonstrated for the first time the pH dependent release from hydrophilic-lipid matrices as well as pH independent release from hydrophobic-lipid matrices for OND SR tablets manufactured by means of a continuous melt granulation technique utilizing a twin-screw extruder.

  13. Stearic acid and high molecular weight PEO as matrix for the highly water soluble metoprolol tartrate in continuous twin-screw melt granulation.

    Science.gov (United States)

    Monteyne, Tinne; Adriaensens, Peter; Brouckaert, Davinia; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

    2016-10-15

    Granules with release-sustaining properties were developed by twin screw hot melt granulation (HMG) using a combination of stearic acid (SA) and high molecular weight polyethylene oxide (PEO) as matrix for a highly water soluble model drug, metoprolol tartrate (MPT). Earlier studies demonstrated that mixing molten SA and PEO resulted in hydrogen bond formation between hydroxyl groups of fatty acid molecules and ether groups in PEO chains. These molecular interactions might be beneficial in order to elevate the sustained release effect of drugs from a SA/PEO matrix. This study aims to investigate the continuous twin screw melt granulation technique to study the impact of a SA/PEO matrix on the dissolution rate of a highly water soluble drug (MPT). Decreasing the SA/PEO ratio improved the release-sustaining properties of the matrix. The solid state of the granules was characterized using differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) and near infrared chemical imaging (NIR-CI) in order to understand the dissolution behavior. The results revealed a preferential interaction of the MPT molecules with stearic acid impeding the PEO to form hydrogen bonds with the stearic acid chains. However, this allowed the PEO chains to recrystallize inside the stearic acid matrix after granulation, hence, elevating the release-sustaining characteristics of the formulation.

  14. Rotor Profiles Design Method and Numerical Simulation for Twin-screw Kneader%双螺杆捏合机转子型线设计与数值模拟

    Institute of Scientific and Technical Information of China (English)

    魏静; 孙旭建; 孙伟; 张光辉

    2013-01-01

    The profile curve design method and the mathematical model of conjugate surfaces of twin-screw kneader used for high viscosity material mixing, transportation and malaxating are established according to principle of gear engagement. One novel twin-screw kneader and the equations of the profile curves of the rotors as well as the rotor design are put forward, and the female and male rotor structures are designed. The working principles of the twin screw kneader are analyzed. The numerical simulation for dynamic characteristics of the flow field of the twin-screw kneader is carried out. The numerical simulation model of twin-screw kneader is established, and the three-dimensional, isothermal and steady numerical analysis of non-newtonian fluid is presented based on computational fluid dynamics (CFD) theory, and the characteristics under the conditions of different speeds and center distances such as the distribution of pressure and velocity field, the maximum shear stress, the mass flow rate and so on, are studied. Based on Fluid-solid coupling theory, the effect of different working conditions, such as fluid pressure, torque, on the twin-screw rotors' stress and deformation is studied by solving the fluid solid coupling equations between internal fluid of kneader and the twin-screw rotors. The results provide a theoretical basis for reasonable designing and optimization of technical parameters for the novel twin-screw kneader.%利用曲面共轭原理建立双螺杆捏合机转子型线设计与螺杆转子共轭曲面啮合方程的数学模型,提出一种可对高黏度物料进行输送、混合及塑化作用的新型双螺杆捏合机螺杆转子型线,给出转子螺旋副组成齿型线参数方程,进行转子结构设计.建立双螺杆捏合机流场数值仿真模型,依据计算流体动力学理论,对非牛顿流体流动进行三维、等温稳态有限元数值分析,研究其在不同转速及中心距条件下流场压力场分布、速度场分

  15. Use of a continuous twin screw granulation and drying system during formulation development and process optimization.

    Science.gov (United States)

    Vercruysse, J; Peeters, E; Fonteyne, M; Cappuyns, P; Delaet, U; Van Assche, I; De Beer, T; Remon, J P; Vervaet, C

    2015-01-01

    Since small scale is key for successful introduction of continuous techniques in the pharmaceutical industry to allow its use during formulation development and process optimization, it is essential to determine whether the product quality is similar when small quantities of materials are processed compared to the continuous processing of larger quantities. Therefore, the aim of this study was to investigate whether material processed in a single cell of the six-segmented fluid bed dryer of the ConsiGma™-25 system (a continuous twin screw granulation and drying system introduced by GEA Pharma Systems, Collette™, Wommelgem, Belgium) is predictive of granule and tablet quality during full-scale manufacturing when all drying cells are filled. Furthermore, the performance of the ConsiGma™-1 system (a mobile laboratory unit) was evaluated and compared to the ConsiGma™-25 system. A premix of two active ingredients, powdered cellulose, maize starch, pregelatinized starch and sodium starch glycolate was granulated with distilled water. After drying and milling (1000 μm, 800 rpm), granules were blended with magnesium stearate and compressed using a Modul™ P tablet press (tablet weight: 430 mg, main compression force: 12 kN). Single cell experiments using the ConsiGma™-25 system and ConsiGma™-1 system were performed in triplicate. Additionally, a 1h continuous run using the ConsiGma™-25 system was executed. Process outcomes (torque, barrel wall temperature, product temperature during drying) and granule (residual moisture content, particle size distribution, bulk and tapped density, hausner ratio, friability) as well as tablet (hardness, friability, disintegration time and dissolution) quality attributes were evaluated. By performing a 1h continuous run, it was detected that a stabilization period was needed for torque and barrel wall temperature due to initial layering of the screws and the screw chamber walls with material. Consequently, slightly deviating

  16. Statistical analysis and comparison of a continuous high shear granulator with a twin screw granulator: Effect of process parameters on critical granule attributes and granulation mechanisms.

    Science.gov (United States)

    Meng, Wei; Kotamarthy, Lalith; Panikar, Savitha; Sen, Maitraye; Pradhan, Shankali; Marc, Michaelis; Litster, James D; Muzzio, Fernando J; Ramachandran, Rohit

    2016-11-20

    This study is concerned with identifying the design space of two different continuous granulators and their respective granulation mechanisms. Performance of a continuous high shear granulator and a twin screw granulator with paracetamol formulations were examined by face-centered cubic design, which focused on investigating key performance metrics, namely, granule size, porosity, flowability and particle morphology of granules as a function of essential input process parameters (liquid content, throughput and rotation speed). Liquid and residence time distribution tests were also performed to gain insights into the liquid-powder mixing and flow behavior. The results indicated that continuous high shear granulation was more sensitive to process variation and produced spherical granules with monomodal size distribution and distinct internal structure and strength variation. Twin screw granulation with such a particular screw configuration showed narrower design space and granules were featured with multimodal size distribution, irregular shape, less detectible porosity difference and tighter range of strength. Granulation mechanisms explored on the basis of nucleation and growth regime maps revealed that for most cases liquid binder was uniformly distributed with fast droplet penetration into the powder bed and that granule consolidation and coalescence mainly took place in the nucleation, steady growth and rapid growth regimes.

  17. Multi-Variable Optimisation Of Wet Vapour Organic Rankine Cycles With Twin-Screw Expanders

    OpenAIRE

    2014-01-01

    A multi-variable optimisation program has been developed to investigate the performance of Wet Organic Rankine Cycles for low temperature heat recovery applications. This cycle model contains a detailed thermodynamic model of the twin-screw expander, and the methods used to match the operation of the expander to the requirements of the cycle are described. The capability of the cycle model has been demonstrated for the case of heat recovery from a source of pressurized hot water at 120°C. The...

  18. Plastification of polymers in twin-screw-extruders: New visualization technic using high-speed imaging

    Energy Technology Data Exchange (ETDEWEB)

    Knieper, A., E-mail: Alexander.Knieper@lbf.fraunhofer.de, E-mail: Christian.Beinert@lbf.fraunhofer.de; Beinert, C., E-mail: Alexander.Knieper@lbf.fraunhofer.de, E-mail: Christian.Beinert@lbf.fraunhofer.de [Group Polymer Processing, Division Plastics, Fraunhofer-Institute LBF (Germany)

    2014-05-15

    The initial melting of the first granules through plastic energy dissipation (PED) at the beginning of the melting zone, in the co-rotating twin-screw extruder is visualized in this work. The visualization was created through the use of a high speed camera in the cross section of the melting zone. The parameters screw speed, granule-temperature, temperature-profile, type of polymer and back pressure were examined. It was shown that the screw speed and the temperature-profile have significant influence on the rate of initial melting.

  19. Some physicochemical properties of dextrin produced by extrusion process

    Directory of Open Access Journals (Sweden)

    Achmat Sarifudin

    2014-06-01

    Full Text Available Dextrinization of corn starch by twin screw extruder was studied. The effect of extruder operating conditions (five different screw speeds: 35, 45, 55, 65, and 70; and three temperatures: 125, 130, and 135 °C on some physicochemical properties of dextrin (total soluble solid, water absorption index, water solubility index, and total color difference was investigated. Results showed that as the screw speed and temperature of extrusion were increased the water absorption index of dextrin tended to drop meanwhile the total soluble solid, water solubility index, and color were inclined to rise. The range of total soluble solid, water absorption index, water solubility index and total color difference was 2.1–4.6 Brix, 159–203%, 20–51%, 3.5–14.1, respectively.

  20. Impact of screw elements on continuous granulation with a twin-screw extruder.

    Science.gov (United States)

    Djuric, Dejan; Kleinebudde, Peter

    2008-11-01

    The influence of different screw element types on wet granulation process with a twin-screw extruder was investigated. Lactose granules were prepared with different screw configurations such as conveying, combing mixer and kneading elements. The use of kneading blocks led to an almost complete agglomeration of lactose, whereas kneading and combing mixer elements resulted in smaller granules in comparison. Granule porosity varied between 17.4% and 50.6%. Granule friability values ranged from 1.2% to 38.5%. Conveying elements led to the most porous and friable granules, whereas kneading blocks produced the densest and least friable granules. Combing mixer elements produced granules with median properties. A linear correlation between granule porosity and the natural logarithm of granule friability was detected. Flowability of granules was also influenced by the element type. Compressed granules with higher granule porosities resulted in tablets with higher tensile strength values and vice versa. Twin-screw extruders proved to be a versatile tool for wet granulation. By the choice of a suitable screw element granule and tablet characteristics were influenced.

  1. Validation of a continuous granulation process using a twin-screw extruder.

    Science.gov (United States)

    Van Melkebeke, B; Vervaet, C; Remon, J P

    2008-05-22

    Using twin-screw granulation as particle size enlargement technique, the effect of modifying the screw configuration (number of mixing zones, configuration of kneading block) on granule quality, tablet properties and mixing efficiency was investigated. The amount of oversized agglomerates and yield was significantly influenced by the presence of an extra conveying element at the screw end. Changing the staggering angle of the kneading block significantly affected yield and granule friability. The 90 degrees configuration resulted in a lower yield and granule friability. Disintegration time was the only tablet property significantly influenced by the screw configuration as disintegration was significantly faster when an extra conveying element was placed at the screw end. The influence of tracer addition method (wet vs. dry) on mixing efficiency inside the extruder barrel was investigated by means of different tracers: riboflavin (0.05%) suspended in the granulation liquid and hydrochlorothiazide (2.5%) added separately as powder. Mixing efficiency in function of time and granule size (above and below 1400 microm) was tested using riboflavine sodium phosphate (0.05%) dissolved in the granulation liquid. Since a good mixing efficiency was obtained independent of tracer addition method, tracer solubility, granulation time and granule size, continuous granulation using a twin-screw extruder was identified as a robust process.

  2. 啤酒糟-玉米膨化食品的双螺杆挤压工艺与配方%Study on Cooking Extrusion Conditions and Formula of Brewer's Spent Grain-corn Snack with Twin-screw Extruder

    Institute of Scientific and Technical Information of China (English)

    郭萌萌; 耿赟; 郝夕祥; 郑路; 杜金华

    2010-01-01

    以玉米、啤酒糟为原料,进行双螺杆挤压膨化试验,开发新型酒糟膨化食品的同时提高啤酒糟的利用效率.以膨化产品的膨化率、硬度和感官特征做为考核指标,由单因素试验结果确定啤酒糟添加量(A)、物料水分(B)、螺杆转速(C)和挤压温度(D)的最佳水平.在单因素试验基础上采用正交试验设计,优化膨化工艺.试验结果表明:在喂料速度25 kg/h时,啤酒糟添加量10%,物料水分17%,螺杆转速300 r/min,挤压温度130℃的条件下,膨化效果最好.与未添加啤酒糟的玉米膨化产品相比,蛋白质和膳食纤维含量明显提高.

  3. How Deformation Behavior Controls Product Performance After Twin Screw Granulation With High Drug Loads and Crospovidone as Disintegrant.

    Science.gov (United States)

    Meier, Robin; Moll, Klaus-Peter; Krumme, Markus; Kleinebudde, Peter

    2017-01-01

    This study addresses the quantitative influence of 12 different materials (active pharmaceutical ingredients and excipients as surrogate active pharmaceutical ingredients) on the critical quality attributes of twin screw granulated products and subsequently produced tablets. Prestudies demonstrated the significant influence of the chosen model materials (in combination with crospovidone) on the disintegration behavior of the resulting tablets, despite comparable tablet porosities. This study elucidates possible reasons for the varying disintegration behavior by investigating raw material, granule, and tablet properties. An answer could be found in the mechanical properties of the raw materials and the produced granules. Through compressibility studies, the materials could be classified into materials with high compressibility, which deform rather plastically under compression stress, and low compressibility, which display breakages under compression stress. In general, and apart from (pseudo)-polymorphic transformations, brittle materials featured excellent disintegration performance, even at low resulting tablet porosities <8%, whereas plastically deformable materials mostly did not reveal any disintegration. These findings must be considered in the development of simplified formulations with high drug loads, in which the active pharmaceutical ingredient predominantly defines the deformation behavior of the granule.

  4. Investigation of an 11mm diameter twin screw granulator: Screw element performance and in-line monitoring via image analysis.

    Science.gov (United States)

    Sayin, Ridade; Martinez-Marcos, Laura; Osorio, Juan G; Cruise, Paul; Jones, Ian; Halbert, Gavin W; Lamprou, Dimitrios A; Litster, James D

    2015-12-30

    As twin screw granulation (TSG) provides one with many screw element options, characterization of each screw element is crucial in optimizing the screw configuration in order to obtain desired granule attributes. In this study, the performance of two different screw elements - distributive feed screws and kneading elements - was studied in an 11 mm TSG at different liquid-to-solid (L/S) ratios. The kneading element configuration was found to break large granules more efficiently, leading to narrower granule size distributions. While pharmaceutical industry shifts toward continuous manufacturing, inline monitoring and process control are gaining importance. Granules from an 11 mm TSG were analysed using the Eyecon™, a real-time high speed direct imaging system, which has been used to capture accurate particle size distribution and particle count. The size parameters and particle count were then assessed in terms of their ability to be a suitable control measure using the Shewhart control charts. d10 and particle count were found to be good indicators of the change in L/S ratio. However, d50 and d90 did not reflect the change, due to their inherent variability even when the process is at steady state.

  5. Three-Dimensional Flow Modeling of a Self-wiping Corotating Twin-Screw Extruder. Part II : The Kneading Section

    NARCIS (Netherlands)

    Wal, D.J. van der; Goffart, D.; Klomp, E.M.; Hoogstraten, H.W.; Janssen, L.P.B.M.

    1996-01-01

    Three-dimensional flow simulations of kneading elements in an intermeshing corotating twin-screw extruder are performed by solving the Navier Stokes equations with a finite element package, Sepran. Instead of using the whole geometry of the 8-shaped barrel a simplified geometry is used, representing

  6. Definition of a JA2 equivalent propellant to be produced by continuous solvent-less extrusion

    NARCIS (Netherlands)

    Manning, T.G.; Leone, J.; Zebregs, M.; Ramlal, D.R.; Driel, C.A. van

    2013-01-01

    The aim of this work is to demonstrate the manufacturing of a propellant by solvent-less continuous twin screw extrusion processing while maintaining gun performance characteristics of conventional JA-2 propellant. This is elucidated by explicitly researching the relationship between interior ballis

  7. effectof extrusion conditions on aflatoxin content of corn–peanut flakes

    African Journals Online (AJOL)

    Aynadis

    ... operating conditions on the reduction of total and individual aflatoxins ... cereals, flakes, breading crumbs and animal feeds. .... rotating twin screw food extruder (model. Clextral, BC-21 .... accepted at 0.05 level of probability. (p<0.05). .... The collective action of the ... monostea rate on the extrusion behavior of maize grits ...

  8. Polycarbonate modified with crystallisable bis-ester tetra-amide units in a reaction extrusion process

    NARCIS (Netherlands)

    Zuiderduin, W.C.J.; Gaymans, R.J.

    2008-01-01

    Dry blends of polycarbonate (PC) and a bis-ester tetra-amide were extruded at 305 °C with a mini twin screw extruder. The bis-ester tetra-amide diamide (T6T6T-dimethyl) was composed of two and a half repeat units of Nylon 6,T and had methyl ester endgroups. During the extrusion, a

  9. Study on the combustion behavior of high impact polystyrene nanocomposites produced by different extrusion processes

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available The combustion behavior of a blend made of high impact polystyrene (HIPS with sodium montmorillonite (MMT-Na+ and triphenyl phosphite (TPP, as a halogen-free flame retardant, is analyzed in detail in this work. The blend is processed through various extrusion methods aimed to improve clay dispersion. The UL94 method in vertical position, oxygen index and cone calorimetric measurements assess HIPS blend behavior in combustion. TGA, FTIR, SEM and X-ray measurements, together with mechanical and rheological tests evaluate the thermal degradation, morphology, intercalation and degree of dispersion of particles. The use of a static-mixing die placed at the extreme of a single screw extruder improves clay platelets distribution and reduces the peak heat release rate better than employing a twin screw extrusion process. In addition, mechanical and rheological properties are affected substantially by changing the extrusion process. A correlation between clay dispersion and HIPS fire retardant properties is found, as the peak heat release rate decreases with good clay dispersion in cone calorimetric tests.

  10. Thermodynamic Simulation on the Performance of Twin Screw Expander Applied in Geothermal Power Generation

    Directory of Open Access Journals (Sweden)

    Yuanqu Qi

    2016-08-01

    Full Text Available A three-dimensional (3D geometry model of twin screw expander has been developed in this paper to measure and analyze geometric parameters such as groove volume, suction port area, and leakage area, which can be described as functions of rotation angle of male rotor. Taking the suction loss, leakage loss, and real gas effect into consideration, a thermodynamic model is developed using continuity and energy conservation equation. The developed model is verified by comparing predicted results of power output and internal efficiency with experimental data. Based on the model, the relationship between mass flow rate through inlet port and leakage path with rotation angle of male rotor as well as effects of the inlet parameter and operating parameter on the performance of the expander are analyzed.

  11. Processing of nanocomposites EVA/PVC/MMT in twin-screw extruder; Processamento de nanocompositos EVA/PVC/MMT em extrusora dupla rosca

    Energy Technology Data Exchange (ETDEWEB)

    Gehlen, A.; Barbutti Filho, W.R.; Francisquetti, E.L.; Andrade, M.Z.; Zattera, A.J., E-mail: ajzatter@ucs.b [Universidade de Caxias do Sul (UCS), RS (Brazil). Lab. de Polimeros

    2010-07-01

    Polymeric nanocomposites have some superior properties when compared to conventional polymer composites and is one of the most promising fields in the nanotechnology research. In a EVA (ethylene vinyl acetate) /PVC (poly vinyl chloride) matrix was incorporated different types of montmorillonite clays (an inorganic (Na{sup +}) and two organic modified (15A and 30B nanoclays). The mixtures were processed in a co-rotating twin-screw extruder at processing speeds of 200 and 400 rpm. Thermogravimetric analysis (TGA) shown that the inorganic and organic modified clays promoted a shift to higher temperatures in the degradation temperature., X-ray diffraction (XRD) and transmission electronic microscopy (TEM) shows a possible intercalation with the 15A clay, exfoliation with the 30B clay and formation of clusters in the Na{sup +} clay. For all clays studied, the increase in shear rate does not promote significant changes. (author)

  12. Mechanical Model and Finite Element Analysis of Screw in Twin-Screw Extruder%双螺杆挤压膨化机螺杆的力学模型及有限元分析

    Institute of Scientific and Technical Information of China (English)

    杨凯; 武凯; 王以龙; 彭斌彬; 孙宇

    2013-01-01

    Twin -screw extrusion technology is a kind of advanced extrusion modeling technology widely applied in feed processing field, plastic processing field and food processing field.lt established mechanical model and finite element model (FEM)of conjugate screw in co-rotating twin-screw extruder and carried out stress analysis on screws in different pitch and SAR through the method of FEAJt is shown that the maximum stress of screw decreases with the increase of pitch of screw and the reduction gradually diminishes, the maximum stress of screw has positive correlation with SAR and SAR has less influence on the maximum stress.the position of the maximum stress of screw is irrelevant to the pitch but related with SAR.%双螺杆挤压膨化技术是一种先进的物料挤压成形技术,广泛应用于饲料加工领域、塑料加工领域及食品加工领域.建立了同向啮合双螺杆挤压膨化机共轭型螺杆的力学模型及有限元模型,并运用有限元分析方法对不同螺距和内径外径比(SAR)的螺杆进行了应力分析.结果表明,螺杆最大应力随着螺距的增加而减小,而且减小的幅度逐渐变小;随着SAR的减小而减小,而且对螺杆最大应力的影响逐渐较小;螺杆最大应力出现的位置与螺距无关而与SAR有关.

  13. Extrusion Processing of Cactus Pear

    Directory of Open Access Journals (Sweden)

    Preetam Sarkar

    2011-04-01

    Full Text Available Whole fruit utilization using extrusion technology has received limited attention in the food processing industry. The objective of this study was to investigate the utilization of prickly pear fruit solids in extruded food products. Peeled prickly pear fruits were ground to form a paste. This paste was strained to remove the seeds and then mixed with rice flour in three different solid ratios. The three blends were dried to a moisture level of 13% (w/w basis and ground to form fine flour. These feed mixes were extruded in a twin screw extruder (Clextral EV-25 at a feed rate of 15 kg/h, feed moisture content of 13% (w/w, screw speed of 400 rpm and L/D ratio of 40:1. The temperature profile from feed to die end was maintained as: 25, 30, 40, 50, 60, 70, 80, 100, 120, 140ºC. The extruded products were analyzed for physical and textural properties. Apparent density and breaking strength of the cactus pear extrudates increased from 116.07 to 229.66 kg/m3 and 58.5 to 178.63 kPa, respectively with increase in fruit solid level. However, true density, porosity and radial expansion ratio decreased from 837.89 to 775.84 kg/m3, 86.12 to 70.34% and 12.37 to 6.6, respectively with increase in fruit solid level. This study demonstrated the potential of extrusion processing to utilize peeled cactus pear fruits for production of expanded food products.

  14. Properties of Starch-Poly(acrylamide-co-2-acrylamido-2-methylpropanesulfonic acid) Graft Copolymers Prepared by Reactive Extrusion

    Science.gov (United States)

    Graft copolymers of starch with acrylamide and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) were prepared by reactive extrusion in a twin-screw extruder. The weight ratio of total monomer to starch was fixed at 1:3, while the molar fraction of AMPS in the monomer feed ranged from 0 to 0.119. Mon...

  15. Preparation and physicochemical characterization of matrix pellets containing APIs with different solubility via extrusion process.

    Science.gov (United States)

    Hegyesi, Diána; Thommes, Markus; Kleinebudde, Peter; Sovány, Tamás; Kása, Péter; Kelemen, András; Pintye-Hódi, Klára; Regdon, Géza

    2017-03-01

    In this study, a multiparticulate matrix system was produced, containing two different active pharmaceutical ingredients (APIs): enalapril-maleate and hydrochlorothiazide. The critical control points of the process were investigated by means of factorial design. Beside the generally used microcrystalline cellulose, ethylcellulose was used as matrix former to achieve modified drug release ensured by diffusion. The matrix pellets were made by extrusion-spheronization using a twin-screw extruder. Some pellet properties (aspect ratio, 10% interval fraction, hardness, deformation process) were determined. The aim of our study was to investigate how the two different APIs with different solubility and particle size influence the process. The amount of the granulation liquid plays a key role in the pellet shaping. A higher liquid feed rate is preferred in the pelletization process.

  16. A one dimensional model for the prediction of extraction yields in a two phases modified twin-screw extruder

    OpenAIRE

    2002-01-01

    Solid/liquid extraction is performed on raw plant substrate with a modified twin-screw extruder (TSE) used as a thermo-mecanochemical reactor. Visual observations and experimental residence time distributions (RTD) are used to develop a solid transport model based on classical chemical engineering method. Modeled and experimental residence times are compared. The transport model is then coupled with a reactive extraction model in order to predict extraction yields.

  17. Quantifying fiber formation in meat analogs under high moisture extrusion using image processing

    Science.gov (United States)

    Ranasinghesagara, J.; Hsieh, F.; Yao, G.

    2005-11-01

    High moisture extrusion using twin-screw extruders shows great promise of producing meat analog products with vegetable proteins. The resulting products have well defined fiber formations; resemble real meat in both visual appearance and taste sensation. Developing reliable non-destructive techniques to quantify the textural properties of extrudates is important for quality control in the manufacturing process. In this study, we developed an image processing technique to automatically characterize sample fiber formation using digital imaging. The algorithm is based on statistical analysis of Hough transform. This objective method can be used as a standard method for evaluating other non-invasive methods. We have compared the fiber formation indices measured using this technique and a non-invasive fluorescence polarization method and obtained a high correlation.

  18. Use of the channel fill level in defining a design space for twin screw wet granulation.

    Science.gov (United States)

    Gorringe, L J; Kee, G S; Saleh, M F; Fa, N H; Elkes, R G

    2017-03-15

    Twin screw wet granulation is a key process in the continuous manufacture of oral solid dosage forms. Previous research has qualitatively suggested that the channel fill level influences the granules produced. In this paper a quantitative measure of the total volumetric fraction of the conveying element channels of the screw filled with powder (φ) was used. Experimental results are shown which demonstrate that very similar particle size distributions can be obtained at the same φ with the same material and screw configuration but radically different solids feed rates and screw speeds. Morphology of the granules also correlates with φ. This is consistent with previous observations in the literature correlating granule attributes with powder feed rate and screw speed but also considers the two parameters in combination. A process design space approach based on φ is proposed. This can be determined empirically, and potentially has value in setting process control strategies, assuring process robustness and allowing process flexibility during the product lifecycle. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Twin screw wet granulation: Effect of process and formulation variables on powder caking during production.

    Science.gov (United States)

    Saleh, Mohammed F; Dhenge, Ranjit M; Cartwright, James J; Hounslow, Michael J; Salman, Agba D

    2015-12-30

    This work focuses on monitoring the behaviour and the mass of the built up/caking of powder during wet granulation using Twin Screw Granulator (TSG). The variables changed during this work are; powder (α-lactose monohydrate and microcrystalline cellulose (MCC)), the screw configuration (conveying and kneading elements) and the weight percentage of hydroxypropyl-methyl cellulose (HPMC) dissolved in the granulation liquid (i.e. changing liquid viscosity). Additionally, the effect of these variables on the size distribution, of the granules produced, was determined. The experiments were conducted using an acrylic transparent barrel. A stainless steel barrel was then used to conduct the two extreme granulation liquid viscosities with two different screw configurations, using lactose only. This was done to compare the findings to those obtained from the transparent barrel for validation purpose. These variables showed to affect the behaviour and the mass of the powder caking as well as the size distribution of granules. Overall, the use of kneading element resulted in uniform behaviour in caking with higher mass. Furthermore, increasing the amount of HPMC resulted in a reduction of the mass of powder caking for lactose, while showing inconsistent trend for MCC. Furthermore, lactose showed to have a greater tendency to cake in comparison to MCC. The results, for lactose, obtained from the stainless steel barrel compared well with their corresponding conditions from the transparent barrel, as the screw configuration and HPMC mass varied.

  20. Influence of liquid in clearances on the operational behaviour of twin screw expanders

    Science.gov (United States)

    Gräßer, Melanie; Brümmer, Andreas

    2015-08-01

    A lot of effort has been expended on understanding the influences of an injected auxiliary liquid on a twin screw expander's performance. Sealed clearances improve performance on the one hand, but involve considerable frictional losses on the other hand. This paper contributes to an evaluation of these opposing effects with regard to the efficiency of screw expanders. First, thermodynamic analyses using the multi-chamber model-based simulation tool KaSim, developed at the Chair of Fluidics, are presented for a test screw expander in order to show the maximum potential of clearance sealing. This analysis involves thermodynamic simulations for sealed and unsealed clearances and leads to an order of priorities for different clearance types. Second, hydraulic losses within front and housing clearances are calculated, applying an analytical model of incompressible one-phase clearance flow. Subsequently dry and wet screw expanders are evaluated while both clearance sealing and frictional losses are considered for the simulation of a liquid-injected machine.

  1. Simplified formulations with high drug loads for continuous twin-screw granulation.

    Science.gov (United States)

    Meier, R; Thommes, M; Rasenack, N; Krumme, M; Moll, K-P; Kleinebudde, P

    2015-12-30

    As different batches of the same excipients will be intermixed during continuous processes, the traceability of batches is complicated. Simplified formulations may help to reduce problems related to batch intermixing and traceability. Twin-screw granulation with subsequent tableting was used to produce granules and tablets, containing drug, disintegrant and binder (binary and ternary mixtures), only. Drug loads up to 90% were achieved and five different disintegrants were screened for keeping their disintegration suitability after wetting. Granule size distributions were consistently mono-modal and narrow. Granule strength reached higher values, using ternary mixtures. Tablets containing croscarmellose-Na as disintegrant displayed tensile strengths up to 3.1MPa and disintegration times from 400 to 466s, resulting in the most robust disintegrant. Dissolution was overall complete and above 96% within 30 min. Na-starch glycolate offers tensile strengths up to 2.8MPa at disintegration times from 25s to 1031s, providing the broadest application window, as it corresponds in some parts to different definitions of orodispersible tablets. Tablets containing micronized crospovidone are not suitable for immediate release, but showed possibilities to produce highly drug loaded, prolonged release tablets. Tablets and granules from simplified formulations offer great opportunities to improve continuous processes, present performances comparable to more complicated formulations and are able to correspond to requirements of the authorities.

  2. Twin-screw extruded lipid implants containing TRP2 peptide for tumour therapy.

    Science.gov (United States)

    Even, Marie-Paule; Bobbala, Sharan; Gibson, Blake; Hook, Sarah; Winter, Gerhard; Engert, Julia

    2017-01-16

    Much effort has been put in the development of specific anti-tumour immunotherapies over the last few years, and several studies report on the use of liposomal carriers for tumour-associated antigens. In this work, the use of lipid implants, prepared using two different extruders, was investigated for sustained delivery in tumour therapy. The implants consisted of cholesterol, soybean lecithin, Dynasan 114, trehalose, ovalbumin (OVA) or a TRP2 peptide, and Quil-A. Implants were first produced on a Haake Minilab extruder, and then a scale-down to minimal quantities of material on a small scale ZE mini extruder was performed. All formulations were characterised in terms of extrudability, implant properties and in vitro release behaviour of the model antigen ovalbumin. The type of extruder used to produce the implants had a major influence on implant properties and the release behaviour, demonstrating that extrusion parameters and lipid formulations have to be individually adapted to each extrusion device. Subsequently, lipid implants containing TRP-2 peptide were extruded on the ZE mini extruder and investigated in vitro and in vivo. The in vivo study showed that mice having received TRP2 loaded implants had delayed tumour growth for 3days compared to groups having received no TRP2.

  3. Expansion of the whole wheat flour extrusion

    DEFF Research Database (Denmark)

    Cheng, Hongyuan; Friis, Alan

    2008-01-01

    A new model framework is proposed to describe the expansion of extrudates with extruder operating conditions based on dimensional analysis principle. The Buckingham pi dimensional analysis method is applied to form the basic structure of the model from extrusion process operational parameters. Us....... Using the Central Composite Design (CCD) method, whole wheat flour was processed in a twin-screw extruder with 16 trials. The proposed model can well correlate the expansion of the 16 trials using 3 regression parameters. The average deviation of the correlation is 5.9%....

  4. Expansion of the whole wheat flour extrusion

    DEFF Research Database (Denmark)

    Cheng, Hongyuan; Friis, Alan

    2008-01-01

    A new model framework is proposed to describe the expansion of extrudates with extruder operating conditions based on dimensional analysis principle. The Buckingham pi dimensional analysis method is applied to form the basic structure of the model from extrusion process operational parameters....... Using the Central Composite Design (CCD) method, whole wheat flour was processed in a twin-screw extruder with 16 trials. The proposed model can well correlate the expansion of the 16 trials using 3 regression parameters. The average deviation of the correlation is 5.9%....

  5. 发达国家新型食品双螺杆挤出机的发展及其应用%The Progress and Application of New Food Twin Screw Extruder in Developed Countries

    Institute of Scientific and Technical Information of China (English)

    张平亮

    2011-01-01

    介绍了国外新型食品双螺杆挤出机,如:PCM型双螺杆挤出机双轴挤出机;异速SCPD型双螺杆挤出机、ZSKMEGA双螺杆挤出机、ZSK60MAXX双螺杆挤出机的原理、性能和应用,提出今后食品双螺杆挤出机的前景和发展方向。%The works and results of new screw extruder at abroad were introduced. The construction, property and application of new screw extruder such as PCM twin screw extruder, SCPD twin screw extruder, ZSK MEGA twin screw extruder, ZSK60MAXX twin screw extruder were described, progress and development of the twin screw extruder of food in future were proposed.

  6. Study on Extrusion Technological Parametersof Brown Rice

    Institute of Scientific and Technical Information of China (English)

    ZhuYongyi; ZhouXianqing; LingLizhong

    2001-01-01

    Abstract: Extrusion is an efficient measure to improve the texture and physic-chemical properties of brown rice. The polynomial degree two model of extrusiontechnological parameters and gelatinized degree, water absorption index, water solubleindex and moisture content of extruded matter was obtained by methods of single factorand response surface methodology, R2=0.9649, 0.8745, 0.9079, 0.8677. The optimaltechnoiogica! parameters of brown rice extrusion were figured out as follows:moisturecontent of brown rice, 11.42%, speed of screw, 30rpm, feeding speed, and 20rpm.

  7. Enhancement of enzymatic accessibility by fibrillation of woody biomass using batch-type kneader with twin-screw elements.

    Science.gov (United States)

    Lee, Seung-Hwan; Teramoto, Yoshikuni; Endo, Takashi

    2010-01-01

    Fibrillation of wood cell walls into submicron and/or nanoscale fibers was successfully carried out in the presence of water by using a batch-type kneader with combination-available twin-screw elements. The results obtained are expected to be used for the application of a twin-screw extruder. Two types of screw combinations were used for applying different shearing and distribution forces. Most of the fibers of the fibrillated products had diameters less than 1 microm, and some of them had diameters less than 100 nm. The maximum glucose yield by enzymatic saccharification was found to be 54.2% in the fibrillated products kneaded for 20 min after ball milling for 20 min using a screw combination for applying high shearing force. The fibrillation increased the surface area of cellulose. The glucose yield was improved by cooking the fibrillated products with water at 135 degrees C under 0.25 MPa, revealing that only mechanical kneading appears to have some limitation to expose cellulose for complete enzymatic saccharification.

  8. Identifying overarching excipient properties towards an in-depth understanding of process and product performance for continuous twin-screw wet granulation.

    Science.gov (United States)

    Willecke, N; Szepes, A; Wunderlich, M; Remon, J P; Vervaet, C; De Beer, T

    2017-02-14

    The overall objective of this work is to understand how excipient characteristics influence the process and product performance for a continuous twin-screw wet granulation process. The knowledge gained through this study is intended to be used for a Quality by Design (QbD)-based formulation design approach and formulation optimization. A total of 9 preferred fillers and 9 preferred binders were selected for this study. The selected fillers and binders were extensively characterized regarding their physico-chemical and solid state properties using 21 material characterization techniques. Subsequently, principal component analysis (PCA) was performed on the data sets of filler and binder characteristics in order to reduce the variety of single characteristics to a limited number of overarching properties. Four principal components (PC) explained 98.4% of the overall variability in the fillers data set, while three principal components explained 93.4% of the overall variability in the data set of binders. Both PCA models allowed in-depth evaluation of similarities and differences in the excipient properties.

  9. Effect of Extrusion Cooking on Bioactive Compounds in Encapsulated Red Cactus Pear Powder

    Directory of Open Access Journals (Sweden)

    Martha G. Ruiz-Gutiérrez

    2015-05-01

    Full Text Available Red cactus pear has significant antioxidant activity and potential as a colorant in food, due to the presence of betalains. However, the betalains are highly thermolabile, and their application in thermal process, as extrusion cooking, should be evaluated. The aim of this study was to evaluate the effect of extrusion conditions on the chemical components of red cactus pear encapsulated powder. Cornstarch and encapsulated powder (2.5% w/w were mixed and processed by extrusion at different barrel temperatures (80, 100, 120, 140 °C and screw speeds (225, 275, 325 rpm using a twin-screw extruder. Mean residence time (trm, color (L*, a*, b*, antioxidant activity, total polyphenol, betacyanin, and betaxanthin contents were determined on extrudates, and pigment degradation reaction rate constants (k and activation energies (Ea were calculated. Increases in barrel temperature and screw speed decreased the trm, and this was associated with better retentions of antioxidant activity, total polyphenol, betalain contents. The betacyanins k values ranged the −0.0188 to −0.0206/s and for betaxanthins ranged of −0.0122 to −0.0167/s, while Ea values were 1.5888 to 6.1815 kJ/mol, respectively. The bioactive compounds retention suggests that encapsulated powder can be used as pigments and to provide antioxidant properties to extruded products.

  10. Effect of extrusion cooking on bioactive compounds in encapsulated red cactus pear powder.

    Science.gov (United States)

    Ruiz-Gutiérrez, Martha G; Amaya-Guerra, Carlos A; Quintero-Ramos, Armando; Pérez-Carrillo, Esther; Ruiz-Anchondo, Teresita de J; Báez-González, Juan G; Meléndez-Pizarro, Carmen O

    2015-05-18

    Red cactus pear has significant antioxidant activity and potential as a colorant in food, due to the presence of betalains. However, the betalains are highly thermolabile, and their application in thermal process, as extrusion cooking, should be evaluated. The aim of this study was to evaluate the effect of extrusion conditions on the chemical components of red cactus pear encapsulated powder. Cornstarch and encapsulated powder (2.5% w/w) were mixed and processed by extrusion at different barrel temperatures (80, 100, 120, 140 °C) and screw speeds (225, 275, 325 rpm) using a twin-screw extruder. Mean residence time (trm), color (L*, a*, b*), antioxidant activity, total polyphenol, betacyanin, and betaxanthin contents were determined on extrudates, and pigment degradation reaction rate constants (k) and activation energies (Ea) were calculated. Increases in barrel temperature and screw speed decreased the trm, and this was associated with better retentions of antioxidant activity, total polyphenol, betalain contents. The betacyanins k values ranged the -0.0188 to -0.0206/s and for betaxanthins ranged of -0.0122 to -0.0167/s, while Ea values were 1.5888 to 6.1815 kJ/mol, respectively. The bioactive compounds retention suggests that encapsulated powder can be used as pigments and to provide antioxidant properties to extruded products.

  11. Development of a HPMC-based controlled release formulation with hot melt extrusion (HME).

    Science.gov (United States)

    Ma, Decheng; Djemai, Abdenour; Gendron, Colleen M; Xi, Hanmi; Smith, Michelle; Kogan, Jessica; Li, Li

    2013-07-01

    The objective of this study was to develop hydroxypropyl methylcellulose (HPMC) based controlled release (CR) formulations via hot melt extrusion (HME) with a highly soluble crystalline active pharmaceutical ingredient (API) embedded In the polymer phase. HPMC is considered a challenging CR polymer for extrusion due to its high glass transition temperature (Tg), low degradation temperature, and high viscosity. These problems were partially overcome by plasticizing the HPMC with up to 40% propylene glycol (PG). Theophylline was selected as the model API. By using differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), dynamic mechanical analysis (DMA), and X-ray powder diffraction (XRPD), the physical properties of the formulations were systematically characterized. Five grades of HPMC (Methocel(®)) - E6, K100LV, K4M, K15M, and K100M - were tested. The extrusion trials were conducted on a 16 mm twIn screw extruder with HPMC/PG placebo and formulations containing theophylline/HPMC/PG (30:42:28, w/w/w). The dissolution results showed sustained release profiles without burst release for the HPMC K4M, K15M, and K100M formulations. The extrudates have good dissolution stability after being stressed for 2 weeks under 40°C/75% RH open dish conditions and the crystalline API form did not change upon storage. Overall, the processing windows were established for the HPMC based HME-CR formulations.

  12. Optimization of critical quality attributes in continuous twin-screw wet granulation via design space validated with pilot scale experimental data.

    Science.gov (United States)

    Liu, Huolong; Galbraith, S C; Ricart, Brendon; Stanton, Courtney; Smith-Goettler, Brandye; Verdi, Luke; O'Connor, Thomas; Lee, Sau; Yoon, Seongkyu

    2017-06-15

    In this study, the influence of key process variables (screw speed, throughput and liquid to solid (L/S) ratio) of a continuous twin screw wet granulation (TSWG) was investigated using a central composite face-centered (CCF) experimental design method. Regression models were developed to predict the process responses (motor torque, granule residence time), granule properties (size distribution, volume average diameter, yield, relative width, flowability) and tablet properties (tensile strength). The effects of the three key process variables were analyzed via contour and interaction plots. The experimental results have demonstrated that all the process responses, granule properties and tablet properties are influenced by changing the screw speed, throughput and L/S ratio. The TSWG process was optimized to produce granules with specific volume average diameter of 150μm and the yield of 95% based on the developed regression models. A design space (DS) was built based on volume average granule diameter between 90 and 200μm and the granule yield larger than 75% with a failure probability analysis using Monte Carlo simulations. Validation experiments successfully validated the robustness and accuracy of the DS generated using the CCF experimental design in optimizing a continuous TSWG process. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Polycarbonate modified with crystallisable bis-ester tetra-amide units in a reaction extrusion process

    NARCIS (Netherlands)

    Zuiderduin, W.C.J.; Gaymans, R.J.

    2008-01-01

    Dry blends of polycarbonate (PC) and a bis-ester tetra-amide were extruded at 305 °C with a mini twin screw extruder. The bis-ester tetra-amide diamide (T6T6T-dimethyl) was composed of two and a half repeat units of Nylon 6,T and had methyl ester endgroups. During the extrusion, a trans-esterificati

  14. Profile extrusion of wood plastic cellular composites and formulation evaluation using compression molding

    Science.gov (United States)

    Islam, Mohammad Rubyet

    Wood Plastic Composites (WPCs) have experienced a healthy growth during the last decade. However, improvement in properties is necessary to increase their utility for structural applications. The toughness of WPCs can be improved by creating a fine cellular structure while reducing the density. Extrusion processing is one of the most economical methods for profile formation. For our study, rectangular profiles were extruded using a twin-screw extrusion system with different grades of HDPE and with varying wood fibre and lubricant contents together with maleated polyethylene (MAPE) coupling agent to investigate their effects on WPC processing and mechanical properties. Work has been done to redesign the extrusion system setup to achieve smoother and stronger profiles. A guiding shaper, submerged in the water, has been designed to guide the material directly through water immediately after exiting the die; instead of passing it through a water cooled vacuum calibrator and then through water. In this way a skin was formed quickly that facilitated the production of smoother profiles. Later on chemical blowing agent (CBA) was used to generate cellular structure in the profile by the same extrusion system. CBA contents die temperatures, drawdown ratios (DDR) and wood fibre contents (WF) were varied for optimization of mechanical properties and morphology. Cell morphology and fibre alignment was characterized by a scanning electron microscope (SEM). A new compression molding system was developed to help in quick evaluation of different material formulations. This system forces the materials to flow in one direction to achieve higher net alignment of fibres during sample preparation, which is the case during profile extrusion. Operation parameters were optimized and improvements in WPC properties were observed compared to samples prepared by conventional hot press and profile extrusion.

  15. Controlled peroxide-induced degradation of polypropylene in a twin-screw extruder: change of molecular weight distribution under conditions controlled by micromixing

    NARCIS (Netherlands)

    Iedema, P.D.; Remerie, K.; van der Ham, M.; Biemond, E.; Tacx, J.

    2011-01-01

    Controlled degradation of polypropylene (PP) by peroxide was carried out in a laboratory twin-screw extruder ZSK 18 and the change in Molecular Weight Distribution (MWD) was measured using Size Exclusion Chromatography-Differential Viscosimetry (SEC-DV). The MWD results were compared to MWD predicti

  16. Thermomechanical and Thermo-mechano-chemical Pretreatment of Wheat Straw using a Twin-screw Extruder

    Directory of Open Access Journals (Sweden)

    Virginie Vandenbossche

    2014-01-01

    Full Text Available Different thermo-mechanical extrusion pretreatments were evaluated as alternatives to traditional biomass pretreatments for lignocellulosic ethanol production. Wheat straw, a commonly available agricultural co-product, was chosen as the substrate model for the study. Five thermo-mechanical pretreatments were evaluated: one purely thermo-mechanical (TM using just water, and the rest thermo-mechano-chemical (TMC, thus using acid, alkaline, oxidant in alkaline medium, and organic solvent. The parietal constituents, hemicelluloses, cellulose, and lignin were quantified to enable the amounts extracted by the pretreatment to be estimated. The digestibility of cellulose was evaluated by quantifying the hydrolysability with an enzyme cocktail. Water thermomechanical treatment gave strong straw defibration; however the digestibility only attained 35%, whereas ground wheat straw was already 22%. This improvement is insufficient to prepare material for direct enzymatic hydrolysis; thus a combination of the thermo-mechanical and chemical treatment is required. All chemical treatments produced greater improvements in cellulose digestibility. For the acidic treatments, hydrolysability was between 42 and 50%, and reached 89% with alkaline pretreatment.

  17. Melt-Mixing by Novel Pitched-Tip Kneading Disks in a co-rotating Twin-Screw Extruder

    CERN Document Server

    Nakayama, Yasuya; Shigeishi, Takashi; Tomiyama, Hideki; Kajiwara, Toshihisa

    2010-01-01

    Melt-mixing in twin-screw extruders is a key process for development of polymer composites, and quantification of mixing performance of kneading elements based on the physical process in them is a challenging problem. We discuss melt-mixing by novel kneading elements, called "pitched-tip kneading disk (ptKD)". Disk-stagger angle and tip angle are the main geometrical parameters of the ptKDs. We investigated four typical arrangements of the ptKDs, which are forwarding and backwarding disk-staggers combined with forwarding and backwarding tips, respectively. Numerical simulations under a certain feed rate and screw revolution speed were performed and mixing process was investigated by using Lagrangian statistics. It is found that the four types had different mixing characteristics, and their mixing processes were explained by a coupling effect of drag flow by disk staggering and pitched-tip and pressure flow, which is controlled by operational conditions.

  18. In vitro analysis and mechanical properties of twin screw extruded single-layered and coextruded multilayered poly(caprolactone) scaffolds seeded with human fetal osteoblasts for bone tissue engineering.

    Science.gov (United States)

    Ergun, Asli; Yu, Xiaojun; Valdevit, Antonio; Ritter, Arthur; Kalyon, Dilhan M

    2011-12-01

    In vitro culturing and mechanical properties of three types of three-dimensional poly(caprolactone) scaffolds with interconnecting open-foam networks are reported. The scaffolds targeted bone tissue regeneration and were fabricated using twin screw extrusion and coextrusion techniques, for continuous mixing/shaping and formation of single or multilayers with distinct and tailorable porosities and pore sizes. Human fetal preosteoblastic cells, hFOB, were cultured on the extruded and coextruded scaffolds under osteogenic supplements and the samples of the resulting tissue constructs were removed and characterized for cell viability and proliferation using the MTS assay, differentiation, and mineralized matrix synthesis via the alkaline phosphatase, ALP, activity and Alizarin Red staining and cell migration using confocal microscopy and scanning electron microscopy. The hFOB cells formed a confluent lining on scaffold surfaces, migrated to the interior and generated abundant extracellular matrix after 2 weeks of culturing, indicative of the promise of such scaffolds for utilization in tissue engineering. The scaffolds and tissue constructs exhibited compressive fatigue behavior that was similar to that of cancellous bone, suggesting the suitability of their use as bone graft substitutes especially for repair of critical-sized defects or nonunion fractures.

  19. Experimental Investigation on the Operating Characteristics of a Semi-hermetic Twin Screw Refrigeration Compressor by means of p-V Diagram

    OpenAIRE

    Wu, Xiaokun; Zhao, Zhaorui; Chen, Wenqing; Xing, Ziwen

    2016-01-01

    In this paper, a comprehensive experimental investigation is carried out to evaluate the operating characteristics of a semi-hermetic twin screw refrigeration compressor at different oil flow rates and slide valve positions under various conditions. The working volume pressure of the compressor is recorded by a serial of sensors arranged in consecutive positions in the housing. These measured pressure data are then transformed into an indicator diagram. Based on the p-V diagrams, the effect m...

  20. Study on the gelatinization of corn starch by enzyme-added extrusion at low temperature%低温加酶挤压玉米淀粉糊化度的研究

    Institute of Scientific and Technical Information of China (English)

    冯秋娟; 肖志刚; 郑广钊; 魏旭; 叶鸿剑

    2011-01-01

    In order to study the behaviors of extrusion conversion of amylase,a in-temperature resistant α-amylase as catalyzer and a twin-screw extruder were used for testing the gelatinization and liquefaction of corn starch,and extrudates with different gelatinization were obtained.On the basis of single factor,the response surface methodology was used to study the barrel temperature,influences of screw speed,moisture of material and enzyme concentration on gelatinization values.The results showed that when barrel temperature of extruded was 71.35℃,moisture of material was 31.81%,rotation speed of extruder was 133.96r/min,enzyme concentration was 3.15u/g,the optimal value of gelatinization was 55.31%.%为了探讨淀粉加酶挤压转化规律,以中温α-淀粉酶为外加酶,利用双螺杆挤压机对玉米淀粉进行了糊化实验研究,获得了不同糊化程度的挤出物;在单因素研究基础上,采用响应面分析方法研究了机筒温度、螺杆转速、物料水分和酶浓度对挤出物糊化度的影响规律。结果表明:在机筒温度为71.35℃、物料水分31.81%、转速133.96r/min、酶浓度3.15u/g条件下,挤压玉米淀粉糊化度的最优值为55.31%。

  1. The influence of screw configuration on the pretreatment performance of a continuous twin screw-driven reactor (CTSR).

    Science.gov (United States)

    Choi, Chang Ho; Um, Byung-Hwan; Oh, Kyeong Keun

    2013-03-01

    A combination of a continuous twin screw-driven reactor (CTSR) and a dilute acid pretreatment was used for the pretreatment of biomass with a high cellulose content and high monomeric xylose hydrolyzate. With the newly modified CTSR screw configuration (Config. 3), the influences of the screw rotational speed (30-60 rpm), of the pretreatment conditions such as acid concentration (1-5%) and reaction temperature (160-175 °C) at the operating condition of biomass feeding rate (1.0 g/min) and acid feeding rate (13.4 mL/min) on the pretreatment performance were investigated. The cellulose content in the pretreated rape straw was 67.1% at the following optimal conditions: barrel temperature of 165 °C, acid concentration of 3.0% (w/v), and screw rotational speed of 30 rpm. According to the three screw configurations, the glucose yields from enzymatic hydrolysis were 70.1%, 72.9%, and 78.7% for screw Configs. 1, 2, and 3, respectively.

  2. Effect of extrusion temperature and moisture content of corn flour on crystallinity and hardness of rice analogues

    Science.gov (United States)

    Budi, Faleh Setia; Hariyadi, Purwiyatno; Budijanto, Slamet; Syah, Dahrul

    2015-12-01

    Rice analogues are food products made of broken rice and/or any other carbohydrate sources to have similar texture and shape as rice. They are usually made by hot extrusion processing. The hot extrusion process may change the crystallinity of starch and influence the characteristic of rice analogues. Therefore, this research aimed to study the effect of moisture content of incoming dough and temperature of extrusion process on the crystallinity and hardness of resulting rice analogues. The dough's were prepared by mixing of corn starch-flour with ratio 10/90 (w/w) and moisture content of 35%, 40% and 45% (w/w) and extrusion process were done at temperature of 70, 80, 90°C by using of twin screw extruder BEX-DS-2256 Berto. The analyses were done to determine the type of crystal, degree of crystallinity, and hardness of the resulting rice analogues. Our result showed that the enhancement of extrusion temperature from 70 - 90°C increased degree of crystallinity from 5.86 - 15.00% to 10.70 - 18.87% and hardness from 1.71 - 4.36 kg to 2.05 - 5.70 kg. The raising of dough moisture content from 35 - 45% decreased degree of crystallinity from 15.00 - 18.87% to 5.86 - 10.70% and hardness from 4.36 - 5.70 kg to 1.71 - 2.05 kg. The increase of degree of crystallinity correlated positively with the increase of hardness of rice analogues (r = 0.746, p = 0.05).

  3. Twin-Screw Extruder and Pellet Accelerator Integration Developments for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Meitner, Steven J [ORNL; Baylor, Larry R [ORNL; Combs, Stephen Kirk [ORNL; Fehling, Dan T [ORNL; Foust, Charles R [ORNL; McGill, James M [ORNL; Rasmussen, David A [ORNL; Maruyama, So [ITER Organization, Cadarache, France

    2011-01-01

    The ITER pellet injection system consisting of a twinscrew frozen hydrogen isotope extruder, coupled to a combination solenoid actuated pellet cutter and pneumatic pellet accelerator, is under development at the Oak Ridge National Laboratory. A prototype extruder has been built to produce a continuous solid deuterium extrusion and will be integrated with a secondary section, where pellets are cut, chambered, and launched with a single-stage pneumatic accelerator into the plasma through a guide tube. This integrated pellet injection system is designed to provide 5 mm fueling pellets, injected at a rate up to 10 Hz, or 3 mm edge localized mode (ELM) triggering pellets, injected at higher rates up to 20 Hz. The pellet cutter, chamber mechanism, and the solenoid operated pneumatic valve for the accelerator are optimized to provide pellet velocities between 200-300 m/s to ensure high pellet survivability while traversing the inner wall fueling guide tubes, and outer wall ELMpacing guide tubes. This paper outlines the current twin-screwextruder design, pellet accelerator design, and the integrationrequired for both fueling and ELM pacing pellets.

  4. Study on Design of Rotor Profile for the Twin Screw Vacuum Pump with Single Thread Tooth

    Science.gov (United States)

    Lu, Y.; Guo, B.; Geng, M. F.

    2015-08-01

    The trapezoidal profile is always used as part of tooth profile in the screw vacuum pump. However, interferential phenomenon occurs when using trapezoidal tooth profile. The arc is added to the trapezoidal profile to obtain the self-conjugate curve. The geometric characters of new profiles are compared with the old ones from view point of area of leakage triangle, length of contacting line, area utility coefficient, and etc. The rotor with the selfconjugate curve has characteristics of the small axial leakage area. Radial leakage from the carryover was within the same volume and would not influence the mass flow rate of the vacuum pump. High ultimate vacuum can be reached by utilizing this profile.

  5. Extrusion Pretreatment of Lignocellulosic Biomass: A Review

    Directory of Open Access Journals (Sweden)

    Jun Zheng

    2014-10-01

    Full Text Available Bioconversion of lignocellulosic biomass to bioethanol has shown environmental, economic and energetic advantages in comparison to bioethanol produced from sugar or starch. However, the pretreatment process for increasing the enzymatic accessibility and improving the digestibility of cellulose is hindered by many physical-chemical, structural and compositional factors, which make these materials difficult to be used as feedstocks for ethanol production. A wide range of pretreatment methods has been developed to alter or remove structural and compositional impediments to (enzymatic hydrolysis over the last few decades; however, only a few of them can be used at commercial scale due to economic feasibility. This paper will give an overview of extrusion pretreatment for bioethanol production with a special focus on twin-screw extruders. An economic assessment of this pretreatment is also discussed to determine its feasibility for future industrial cellulosic ethanol plant designs.

  6. 双螺旋流变压铸AZ91D镁合金的研究%Rheo-Die Casting of AZ91D Magnesium Alloy by Twin-Screw Stirring

    Institute of Scientific and Technical Information of China (English)

    马跃宇; 杨必成; 王亚宝; 徐骏

    2013-01-01

    液态压铸是镁合金最主要的成形方式,但液态压铸件存在气孔等缺陷,限制了镁合金的进一步推广使用.介绍了采用双螺旋流变制浆技术,对镁合金AZ91D进行了流变压铸研究.首先,将镁合金AZ91D熔体浇入到双螺旋流变制浆机中,然后根据不同工艺参数制备流变镁合金浆料,待制浆结束后,将半固态浆料转移到压铸机内,制得半固态压铸件.采用Micro-Image Analysis&Process(MIAP)软件分析了双螺旋流变制浆工艺参数(搅拌温度、搅拌时间和转速)对镁合金AZ91D的初生相晶粒大小的影响,并研究了镁合金压铸成形性.结果表明:随着搅拌温度的降低,晶粒尺寸变化不是很大;随着搅拌时间延长,镁合金晶粒尺寸逐渐增大;随着搅拌速度的增加,镁合金平均晶粒尺寸减少.镁合金流变压铸件中的初生α相由搅拌中形成的球状晶及压铸过程中二次凝固形成的更为细小的球状晶组成.对比了普通压铸件与流变压铸件热处理后的力学性能,流变压铸件的力学性能得到大幅提高,其原因归结为铸态组织的细小和均匀化.%The liquid die casting is the main forming technique of magnesium alloys. However, in die cast components, some defects such as pores and so on restrained further applications of magnesium alloys. In this paper, rheo-die casting of AZ91D magnesium alloy prepared by twin-screw stirring technique was studied. Firstly, AZ91D magnesium alloy melt was put into a twin-screw stirring machine ; then, rheo-slurries were fabricated by twin-screw stirring according to different parameters. Lastly, the slurries were transferred into a die casting machine and rheo-die casting components were made. Effects of rheo-slurries processing parameters (temperature, time and speed) on the sizes of primary phase and performances of the die cast components were researched. The results showed that the grains changed little with the temperatures decreasing. When

  7. Study on Production of Starch Based Fat Substitute by Enzymatic Extrusion%加酶挤压生产淀粉基脂肪替代品的研究

    Institute of Scientific and Technical Information of China (English)

    冯秋娟; 肖志刚

    2011-01-01

    为了研究加酶挤压法生产淀粉基脂肪替代品的可行性,以玉米淀粉为原料,以DE值为指标,利用双螺杆挤压机研究物料水分、机筒温度、螺杆转速、加酶量对DE值的影响;在单因素的基础上,采用响应面分析法作图分析.结果表明:按照研究操作条件,加酶挤压法可以生产淀粉基脂肪替代品(DE值为2.882 -9.963).加酶量和物料水分对DE值的影响显著,螺杆转速对DE值的影响不明显,DE值随加酶量和物料水分的增加而增大,随机筒温度的增加先增大后减小.%In order to study the feasibility of the production of starch based fat substitute by enzyme - added extrusion, corn starch was used as a raw material and a twin screw extruder was used to study the effects of material moisture,barrel temperature, screw speed and enzyme concentration on DE value. On the basis of single factor,the response surface methodology was applied in this study. It showed that the starch based fat substitute ( DE value is 2. 882 ~ 9. 963 ) can be produced by enzyme - added extrusion according to the operating conditions used in this stud-y. The effects of enzyme concentration and material moisture on the DE value were significant, while the effect of screw speed was not. The DE value increased with the increase-of enzyme concentration and material moisture, while it increased firstly and then decreased with the increase of the barrel temperature.

  8. Antimicrobial Activity of Nisin and Natamycin Incorporated Sodium Caseinate Extrusion-Blown Films: A Comparative Study with Heat-Pressed/Solution Cast Films.

    Science.gov (United States)

    Colak, Basak Yilin; Peynichou, Pierre; Galland, Sophie; Oulahal, Nadia; Prochazka, Frédéric; Degraeve, Pascal

    2016-05-01

    Antimicrobial edible films based on sodium caseinate, glycerol, and 2 food preservatives (nisin or natamycin) were prepared by classical thermomechanical processes. Food preservatives were compounded (at 65 °C for 2.5 min) with sodium caseinate in a twin-screw extruder. Anti-Listeria activity assays revealed a partial inactivation of nisin following compounding. Thermoplastic pellets containing food preservatives were then used to manufacture films either by blown-film extrusion process or by heat-press. After 24 h of incubation on agar plates, the diameters of K. rhizophila growth inhibition zones around nisin-incorporated films prepared by solution casting (control), extrusion blowing or heat pressing at 80 °C for 7 min of nisin-containing pellets were 15.5 ± 0.9, 9.8 ± 0.2, and 8.6 ± 1.0 mm, respectively. Since heat-pressing for 7 min at 80 °C of nisin-incorporated pellets did not further inactivate nisin, this indicates that nisin inactivation during extrusion-blowing was limited. Moreover, the lower diameter of the K. rhizophila growth inhibition zone around films prepared with nisin-containing pellets compared to that observed around films directly prepared by solution casting confirms that nisin inactivation mainly occurred during the compounding step. Natamycin-containing thermoplastic films inhibited Aspergillus niger growth; however, by contrast with nisin-containing films, heat-pressed films had higher inhibition zone diameters than blown films, therefore suggesting a partial inactivation of natamycin during extrusion-blowing.

  9. Novel Controlled Release Polymer-Lipid Formulations Processed by Hot Melt Extrusion.

    Science.gov (United States)

    Maniruzzaman, Mohammed; Islam, Muhammad T; Halsey, Sheelagh; Amin, Devyani; Douroumis, Dennis

    2016-02-01

    The aim of the study was to investigate the effect of novel polymer/lipid formulations on the dissolution rates of the water insoluble indomethacin (INM), co-processed by hot melt extrusion (HME). Formulations consisted of the hydrophilic hydroxypropyl methyl cellulose polymer (HPMCAS) and stearoyl macrogol-32 glycerides-Gelucire 50/13 (GLC) were processed with a twin screw extruder to produce solid dispersions. The extrudates characterized by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and hot stage microscopy (HSM) indicated the presence of amorphous INM within the polymer/lipid matrices. In-line monitoring via near-infrared (NIR) spectroscopy revealed significant peak shifts indicating possible interactions and H-bonding formation between the drug and the polymer/lipid carriers. Furthermore, in vitro dissolution studies showed a synergistic effect of the polymer/lipid carrier with 2-h lag time in acidic media followed by enhanced INM dissolution rates at pH > 5.5.

  10. Optimization of Twin-Screw Superchargers for Combined Compressor - Expander Performance (SCREW); Optimierung von Schraubenladern fuer den kombinierten Verdichtungs- und Expansionsbetrieb (SCREW)

    Energy Technology Data Exchange (ETDEWEB)

    Romba, M. [Dortmund Univ. (Germany). Fachgebiet Fluidenergiemaschinen

    2005-07-01

    During the last years the use of mechanical superchargers has gained increasing interest in a bid to combine attractive emission- and fuel consumption values with dynamic driving performance. Based on an analysis of available supercharging systems the development potential of twin screw superchargers is assessed. A concept using inlet slide valves is developed which allows at the same time to control the mass flow delivered by the supercharger and achieve an expansion of the transported charge under part load conditions when the delivered pressure is lower than ambient pressure, achieving a reduction in necessary shaft power or even the delivery of shaft power. To distinguish it from conventional superchargers the new device is called ''SCREW'' - screw type machine with compressor respectively expander working mode. The effect of several design parameters on the SCREW'S performance is evaluated by extensive simulation calculations, showing that a suitable design varies considerably from conventional supercharger designs and that a significant amount of further research, especially covering the development of rotor profiles suited for the specific task, is still needed to fully utilize the concept's potential. As a proof of concept prototype SCREW'S, based on a conventional twin screw supercharger, have been built and tested. The results obtained made clear the general suitability of the concept but also underlined the shortcomings of the prototype as they had already been predicted by the simulations. (orig.)

  11. Mixing and transport during pharmaceutical twin-screw wet granulation: Experimental analysis via chemical imaging

    DEFF Research Database (Denmark)

    Kumar, Ashish; Vercruysse, Jurgen; Toiviainen, Maunu;

    2014-01-01

    a significant interaction between screw design parameters (number and stagger angle of kneading discs) and the process parameters (material throughput and number of kneading discs). The results of the study will allow the development and validation of a transport model capable of predicting the RTD and macro...

  12. The modelling of counter-rotating twin screw extruders as reactors for single-component reactions

    NARCIS (Netherlands)

    Ganzeveld, K.J.; Capel, J.E.; Wal, D.J. van der; Janssen, L.P.B.M.

    1994-01-01

    Numerical models are useful to study the behaviour of the extruder as a polymerization reactor. With a correct numerical model a theoretical analysis of the influence of several reaction and extruder parameters can be made, the limitations of the use of the extruder reactor can be determined and the

  13. The modelling of counter-rotating twin screw extruders as reactors for single-component reactions

    NARCIS (Netherlands)

    Ganzeveld, K.J.; Capel, J.E.; Wal, D.J. van der; Janssen, L.P.B.M.

    1994-01-01

    Numerical models are useful to study the behaviour of the extruder as a polymerization reactor. With a correct numerical model a theoretical analysis of the influence of several reaction and extruder parameters can be made, the limitations of the use of the extruder reactor can be determined and the

  14. Reactive Extrusion for In-situ Chemical Modification of Cellulose with De-Octenyl succinic anhydride (DDSA in presence of Ionic liquid

    Directory of Open Access Journals (Sweden)

    Magdi Elamin Gibril

    2012-07-01

    Full Text Available Modification of microcrystalline cellulose by means of DDSA through the reactive extrusion process was preformed. The process was carried out by twin screw extruder in the presence of ionic liquids (IL, 1-butyl-3- methylimidazolium chloride [Bmim]Cl. The suitable composition for cellulose/IL mixture and optimum conditions for extrusion process were determined. Degree of substitution (DS for modified cellulose was found to be in the range of 0.100- 0.284. In order to study the chemical structure and the physical properties of the modified cellulose, characterization was done by FT-IR, solid-state CP/MAS 13CNMR, and theromgravimetric analysis. FT-IR data were found to have a new peak in contrast to original reactant which clearly indicated the presence of a chemical group. CP/MAS 13CNMR analysis approved the existence of succinylation between cellulose and DDSA. The TGA analysis showed that the thermal stability of modified cellulose was decreased upon increasing of the degree of substitution (DS or the increasing of the amount of DDSA in the samples.

  15. Numerical Studies of Low Cycle Fatigue in Forward Extrusion Dies

    DEFF Research Database (Denmark)

    Pedersen, Thomas Ø

    2000-01-01

    Forward extrusion dies typically fail due to transverse fatigue cracks or wear. Fatigue cracks are initiated in regions where the material is subjected to repeated plastic deformations, e.g. the transition radius in a forward extrusion die, in the present work, a material model capable of describ...

  16. 3D CFD analysis of an oil injected twin screw expander

    OpenAIRE

    Papeš, Iva; Degroote, Joris; Vierendeels, Jan

    2014-01-01

    Small scale Organic Rankine Cycle (ORC) systems have a big potential for waste heat recovery in the market. Due to the smaller volume flows inside these systems, non-conventional expansion technologies such as screw expanders become more interesting. Recent economic studies have shown the important role of screw machines in such cycles. However, in order to get a better understanding of the expansion behaviour in an ORC, appropriate simulation models of screw expanders are necessary. The flow...

  17. Conceptual framework for model-based analysis of residence time distribution in twin-screw granulation

    DEFF Research Database (Denmark)

    Kumar, Ashish; Vercruysse, Jurgen; Vanhoorne, Valerie

    2015-01-01

    within each module where different granulation rate processes dominate over others. Currently, experimental data is used to determine the residence time distributions. In this study, a conceptual model based on classical chemical engineering methods is proposed to better understand and simulate...... the residence time distribution in a TSG. The experimental data were compared with the proposed most suitable conceptual model to estimate the parameters of the model and to analyse and predict the effects of changes in number of kneading discs and their stagger angle, screw speed and powder feed rate...

  18. Study On Extrusion Technological Parameters Of Brown Rice

    Institute of Scientific and Technical Information of China (English)

    Zhu Yongyi; Zhou Xianqing; Ling Lizhong

    2001-01-01

    Extrusion is an efficient measure to improve the texture and physic-s of brown rice. The polynomial degree two model of extrusion parameters and gelatinized degree, water absorption index, water soluble index and moisture content of extruded matter was obtained by methods of single factor and response surface methodology, R2=0.9649, 0.8745, 0.9079, 0.8677. The optimal parameters of brown rice extrusion were figured out as follows:moisture nrice, 11.42%, speed of screw, 30rpm, feeding speed, and 20rpm.

  19. Experimental and Numerical Study on the Strength of Aluminum Extrusion Welding

    Directory of Open Access Journals (Sweden)

    Sedat Bingöl

    2015-07-01

    Full Text Available The quality of extrusion welding in the extruded hollow shapes is influenced significantly by the pressure and effective stress under which the material is being joined inside the welding chamber. However, extrusion welding was not accounted for in the past by the developers of finite element software packages. In this study, the strength of hollow extrusion profile with seam weld produced at different ram speeds was investigated experimentally and numerically. The experiments were performed on an extruded hollow aluminum profile which was suitable to obtain the tensile tests specimens from its seam weld’s region at both parallel to extrusion direction and perpendicular to extrusion direction. A new numerical modeling approach, which was recently proposed in literature, was used for numerical analyses of the study. The simulation results performed at different ram speeds were compared with the experimental results, and a good agreement was obtained.

  20. A comparative study between melt granulation/compression and hot melt extrusion/injection molding for the manufacturing of oral sustained release thermoplastic polyurethane matrices.

    Science.gov (United States)

    Verstraete, G; Mertens, P; Grymonpré, W; Van Bockstal, P J; De Beer, T; Boone, M N; Van Hoorebeke, L; Remon, J P; Vervaet, C

    2016-11-20

    During this project 3 techniques (twin screw melt granulation/compression (TSMG), hot melt extrusion (HME) and injection molding (IM)) were evaluated for the manufacturing of thermoplastic polyurethane (TPU)-based oral sustained release matrices, containing a high dose of the highly soluble metformin hydrochloride. Whereas formulations with a drug load between 0 and 70% (w/w) could be processed via HME/(IM), the drug content of granules prepared via melt granulation could only be varied between 85 and 90% (w/w) as these formulations contained the proper concentration of binder (i.e. TPU) to obtain a good size distribution of the granules. While release from HME matrices and IM tablets could be sustained over 24h, release from the TPU-based TSMG tablets was too fast (complete release within about 6h) linked to their higher drug load and porosity. By mixing hydrophilic and hydrophobic TPUs the in vitro release kinetics of both formulations could be adjusted: a higher content of hydrophobic TPU was correlated with a slower release rate. Although mini-matrices showed faster release kinetics than IM tablets, this observation was successfully countered by changing the hydrophobic/hydrophilic TPU ratio. In vivo experiments via oral administration to dogs confirmed the versatile potential of the TPU platform as intermediate-strong and low-intermediate sustained characteristics were obtained for the IM tablets and HME mini-matrices, respectively.

  1. A study on material flow in isothermal extrusion by FEM simulation

    Science.gov (United States)

    Peng, Zhi; Sheppard, Terry

    2004-09-01

    Numerous methods have been suggested or are being used to employ isothermal extrusion operation in commercial presses. The most popular methods may be broadly divided into two types: setting up a longitudinal thermal gradient in the billet or controlling the extrudate exit temperature by varying the ram speed. If the velocity gradient varies it could cause the extrusion to bend or twist, creating residual stress, and the same is true for variation in temperature. So, it is relevant to understand how the material flows through the die and ascertain how the flow pattern in isothermal extrusion differs from the normal extrusion process. In this study, with the help of previous experiments and finite element method (FEM) simulations, isothermal extrusion by two differing methodologies are investigated and discussed: the material flow pattern and the extrudate surface formation in isothermal extrusion. The extrusion force, the exit temperature, the temperature distribution in the transverse direction of the extrudate, the pressure on the tooling, the strain and strain rate distribution are also discussed to assist in the evaluation of isothermal extrusion.

  2. Chemicals effect on the enzymatic digestibility of rape straw over the thermo-mechanical pretreatment using a continuous twin screw-driven reactor (CTSR).

    Science.gov (United States)

    Um, Byung-Hwan; Choi, Chang Ho; Oh, Kyeong Keun

    2013-02-01

    Rape straw pretreated by a continuous twin screw-driven reactor (CTSR) with hot water presented a distinctive particle-size distribution profile as a function of the operating temperature. The relative amount of finer particle size dramatically increased as the ratio of solid to liquid was increased. Size reduction through physical CTSR process effectively promoted the enzymatic hydrolysis of pretreated rape straw. Meanwhile, the crystallinity of the physically pretreated straw was not a greater factor affecting the enzyme digestibility. The glucose conversion from the enzymatic hydrolysis of the straw pretreated by CTSR with hot water was maximized at 52%. Using the chemicals as catalyst have affected considerably for increasing the digestibility at same condition with hot water pretreatment. The enzymatic digestibilities of the straw pretreated by CTSR with sodium hydroxide and sulfuric acid were 60% and 77%, respectively.

  3. Performance of Semi-solid Slurry Produced by Twin-screw Stirring Mixer and Rheo-diecasting Process of AZ91D Alloy

    Institute of Scientific and Technical Information of China (English)

    XIAO Ze-hui; LUO Ji-rong; WU Shu-sen; LI Dong-nan

    2004-01-01

    The microstructure of semi-solid slurry of AZ91D alloy, which was produced by twin-screw stirring mixer under the different parameters, was investigated.Rheoforming by cold chamber die casting process was performed thereafter. The results indicate that with decreasing of the barrel temperature of the mixer and the pouring temperature of molten Mg alloy, the solid fraction of semi-solid slurry increases and the size of non-dendritic grains becomes smaller. While the shear rate increases, the solid fraction of semi-solid slurry decreases. The tensile strength and elongation of metal rheoformed by die casting are higher by about 37% and 44% respectively than those produced by conventional liquid die casting.

  4. Indication of worn WC/C surface locations of a dry-running twin-screw rotor by the oxygen incorporation in tungsten-related Raman modes

    Science.gov (United States)

    Debus, J.; Schindler, J. J.; Waldkirch, P.; Goeke, S.; Brümmer, A.; Biermann, D.; Bayer, M.

    2016-10-01

    By comparing the worn and untouched locations of a tungsten-carbide/carbon surface of a dry-running twin-screw rotor, we demonstrate that tungsten-oxide Raman modes become observable only at worn locations and the integral intensity of the Raman line at 680 cm-1, which is related to the incipient oxidation of the tungsten-carbide stretching mode, is enhanced. Its frequency and width moreover change significantly, thus indicating the mechanical distortion of the bonding that has been occurred during the wearing process. The shape of the tungsten-oxide Raman lines, resembling the Voigt function, hints at a surface morphology that is a characteristic for an amorphous solid environment. Our Raman scattering results may be exploited to characterize the degree of wear of coated surfaces and to identify signatures of a tribological layer.

  5. Viability loss of Escherichia coli cell populations in whey and corn meal snack treated at different temperatures with a twin screw extruder

    Science.gov (United States)

    Many studies on the development of new and/ or value added nutritional meals for the US consumer have been reported. However, information on the effect of treatment parameters on microbial safety of foods extruded below 100 deg C is limited. In this study, we investigated the effect of extrusion tre...

  6. Thermal Stabilization study of polyacrylonitrile fiber obtained by extrusion

    Directory of Open Access Journals (Sweden)

    Robson Fleming Ribeiro

    2015-12-01

    Full Text Available A low cost and environmental friendly extrusion process of the Polyacrylonitrile (PAN polymer was viabilized by using the 1,2,3-propanetriol (glycerol as a plasticizer. The characterization of the fibers obtained by this process was the object of study in the present work. The PAN fibers were heat treated in the range of 200 °C to 300 °C, which is the temperature range related to the stabilization/oxidation step. This is a limiting phase during the carbon fiber processing. The characterization of the fibers was made using infrared spectroscopy, thermal analysis and microscopy. TGA revealed that the degradation of the extruded PAN co-VA fibers between 250 °C and 350 °C, corresponded to a 9% weight loss to samples analyzed under oxidizing atmosphere and 18% when the samples were analyzed under inert atmosphere. DSC showed that the exothermic reactions on the extruded PAN co-VA fibers under oxidizing synthetic air was broader and the cyclization started at a lower temperature compared under inert atmosphere. Furthermore, FT-IR analysis correlated with thermal anlysis showed that the stabilization/oxidation process of the extruded PAN fiber were coherent with other works that used PAN fibers obtained by other spinning processes.

  7. Study of the Mechanical and Morphology Properties of Recycled HDPE Composite Using Rice Husk Filler

    Directory of Open Access Journals (Sweden)

    Jia Ying Tong

    2014-01-01

    Full Text Available WPCs are being used in a large number of applications in the automotive, construction, electronic, and aerospace industries. There are an increasing number of research studies and developments in WPC technology involving rice husk as fillers. This study investigated the effects of different compositions of rice husk (RH filler on the mechanical and morphological properties of recycled HDPE (rHDPE composite. The composites were prepared with five different loading contents of RH fibers (0, 10, 20, 30, and 40 wt% using the twin screw extrusion method. Maleic acid polyethylene (MAPE was added as a coupling agent. Results showed that tensile and flexural properties improved with increasing RH loading. However, the impact strength of the composites decreased as the RH loading increased. SEM micrographs revealed good interfacial bonding between the fiber and polymer matrix.

  8. The thermo-mechano-chemical twin-screw reactor, a new perspective for the biorefinery of sunflower whole plant : Aqueous extraction of oil and other biopolymers, and production of biodegradable fiberboards from cake

    OpenAIRE

    2016-01-01

    Biorefinery of sunflower whole plant was performed successfully using a thermo-mechano-chemical twin-screw reactor. This led to the aqueous extraction of oil and other biopolymers like proteins, pectins and non pectic sugars. It resulted in the overall fractionation of biomass, thus allowing a complete valorization of the input. This biorefinery process was not only efficient but it was also environment-friendly. In addition, it contributed to the production of different end products for vari...

  9. Physicochemical and Microstructural Characterization of Corn Starch Edible Films Obtained by a Combination of Extrusion Technology and Casting Technique.

    Science.gov (United States)

    Fitch-Vargas, Perla Rosa; Aguilar-Palazuelos, Ernesto; de Jesús Zazueta-Morales, José; Vega-García, Misael Odín; Valdez-Morales, Jesús Enrique; Martínez-Bustos, Fernando; Jacobo-Valenzuela, Noelia

    2016-09-01

    Starch edible films (EFs) have been widely studied due to their potential in food preservation; however, their application is limited because of their poor mechanical and barrier properties. Because of that, the aim of this work was to use the extrusion technology (Ex T) as a pretreatment of casting technique to change the starch structure in order to obtain EFs with improved physicochemical properties. To this, corn starch and a mixture of plasticizers (sorbitol and glycerol, in different ratios) were processed in a twin screw extruder to generate the starch modification and subsequently casting technique was used for EFs formation. The best conditions of the Ex T and plasticizers concentration were obtained using response surface methodology. All the response variables evaluated, were affected significatively by the Plasticizers Ratio (Sorbitol:Glycerol) (PR (S:G)) and Extrusion Temperature (ET), while the Screw Speed (SS) did not show significant effect on any of these variables. The optimization study showed that the appropriate conditions to obtain EFs with the best mechanical and barrier properties were ET = 89 °C, SS = 66 rpm and PR (S:G) = 79.7:20.3. Once the best conditions were obtained, the optimal treatment was characterized according to its microstructural properties (X-ray diffraction, Scanning Electron Microscopy and Atomic Force Microscopy) to determine the damage caused in the starch during Ex T and casting technique. In conclusion, with the combination of Ex T and casting technique were obtained EFs with greater breaking strength and deformation, as well as lower water vapor permeability than those reported in the literature. © 2016 Institute of Food Technologists®

  10. Hot Melt Extrusion for Sustained Protein Release: Matrix Erosion and In Vitro Release of PLGA-Based Implants.

    Science.gov (United States)

    Cossé, Anne; König, Corinna; Lamprecht, Alf; Wagner, Karl G

    2017-01-01

    The design of biodegradable implants for sustained release of proteins is a complex challenge optimizing protein polymer interaction in combination with a mini-scale process which is predictive for production. The process of hot melt extrusion (HME) was therefore conducted on 5- and 9-mm mini-scale twin screw extruders. Poly(lactic-co-glycolic acid) (PLGA) implants were characterized for their erosion properties and the in vitro release of the embedded protein (bovine serum albumin, BSA). The release of acidic monomers as well as other parameters (pH value, mass loss) during 16 weeks indicated a delayed onset of matrix erosion in week 3. BSA-loaded implants released 17.0% glycolic and 5.9% lactic acid after a 2-week lag time. Following a low burst release (3.7% BSA), sustained protein release started in week 4. Storage under stress conditions (30°C, 75% rH) revealed a shift of erosion onset of 1 week (BSA-loaded implants: 26.9% glycolic and 9.3% lactic acid). Coherent with the changed erosion profiles, an influence on the protein release was observed. Confocal laser scanning and Raman microscopy showed a homogenous protein distribution throughout the matrix after extrusion and during release studies. Raman spectra indicated a conformational change of the protein structure which could be one reason for incomplete protein release. The study underlined the suitability of the HME process to obtain a solid dispersion of protein inside a polymeric matrix providing sustained protein release. However, the incomplete protein release and the impact by storage conditions require thorough characterization and understanding of erosion and release mechanisms.

  11. New investigation of distribution imaging and content uniformity of very low dose drugs using hot-melt extrusion method.

    Science.gov (United States)

    Park, Jun-Bom; Kang, Chin-Yang; Kang, Wie-Soo; Choi, Han-Gon; Han, Hyo-Kyung; Lee, Beom-Jin

    2013-12-31

    The content uniformity of low dose drugs in dosage forms is very important for quality assurance. The aim of this study was to prepare uniformly and homogeneously distributed dosage forms of very low-dose drugs using twin screw hot-melt extrusion (HME) and to investigate the distribution of drugs using instrumental analyses. For the feasibility of HME method, a very low amount of coumarin-6, a fluorescent dye, was used to visualize distribution images using confocal laser scanning microscope (CLSM). Limaprost, tamsulosin and glimepiride were then used as low-dose model drugs to study the applicability of HME for content uniformity and distribution behaviors. Hydrophilic thermosensitive polymers with low melting point, such as Poloxamer188 and polyethylene glycol (PEG) 6000, were chosen as carriers. The melt extrusion was carried out around 50°C, at which both carriers were easily dissolved but model drugs remained in solid form. The physicochemical properties of the hot-melt extrudates, including differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FT-IR), were measured. Content uniformity of the drugs was also checked by HPLC. CLSM imaging showed that model drugs were well distributed throughout the hot-melt extrudate, giving better content uniformity with low batch-to-batch variations compared with simple physical mixtures. DSC, PXRD and FT-IR data showed that there was no interaction or interference between model drugs and thermosensitive polymers. The current HME methods could be used to prepare uniformly distributed and reproducible solid dosage forms containing very low dose drugs for further pharmaceutical applications.

  12. 双螺杆挤压制备谷物营养早餐的研究%Preparation of a nutritional Eereal Breakfast Food through Extrusion

    Institute of Scientific and Technical Information of China (English)

    蒋长兴; 魏益民

    2012-01-01

    The mixture of com, rice, and millet was extruded in Brabender Lab-station of DSE-25 Twin-Screw Extruder. The effects of multi-grain, sucrose, and distilled monoglyceride on the extrudate qualities and extrusion system parameters were studied. The best recipe for the nutritional cereal breakfast food was determined as follows: corn 60%, rice 20%, millet 20%, sucrose 8%, saccharin 0.1% and salt 0.5%. Under these conditions, the product obtained had improved qualities of color, texutre and flavor.%以玉米、大米、小米的混合粉为材料,采用DSE-25型双螺杆挤压膨化实验室工作站加工谷物营养早餐食品,研究物料配比、蔗糖和单干酯添加量对产品质量指标和设备系统参数的影响,获得谷物营养早餐食品较优配方:玉米、大米、小米混合比例6∶2∶2(m/m),砂糖8%,甜蜜素0.1%,食盐0.5%.在此条件下,产品口感酥脆、颜色金黄、风味独特.

  13. Bioconversion of sawdust into ethanol using dilute sulfuric acid-assisted continuous twin screw-driven reactor pretreatment and fed-batch simultaneous saccharification and fermentation.

    Science.gov (United States)

    Kim, Tae Hyun; Choi, Chang Ho; Oh, Kyeong Keun

    2013-02-01

    Ethanol production from poplar sawdust using sulfuric acid-assisted continuous twin screw-driven reactor (CTSR) pretreatment followed by simultaneous saccharification and fermentation (SSF) was investigated. Pretreatment with high acid concentration increased the cellulose content in the pretreated solid (74.9-76.9% in the range of 4.0-5.5wt.% H(2)SO(4)). The sugar content (XMG; xylan+mannan+galactan) in the treated-solid was 11.1-15.2% and 0.9-5.7% with 0.5wt.% and 7.0wt.%, respectively. The XMG recovery yield of the sample treated with 4.0wt.% H(2)SO(4) at 185°C was maximized at 88.6%. Enzymatic hydrolysis test showed a cellulose digestibility of 67.1%, 70.1%, and 73.6% with 15, 30, and 45FPU/g-cellulose, respectively. In the fed-batch SSF tests with initial enzyme addition, the ethanol yield of each stage almost reached a maximum at 28h, 48h, and 56h, respectively, with yields of 63.9% (16.5g/L), 78.4% (30.1g/L), and 81.7% (39.9g/L), respectively.

  14. Highly viscous fluid flow in the kneading zone of a corotating twin-screw extruder; Die Stroemung hochviskoser Fluessigkeiten im Knetbereich einer Gleichdralldoppelschnecke

    Energy Technology Data Exchange (ETDEWEB)

    Wuensch, O.; Boehme, G. [Universitaet der Bundeswehr, Hamburg (Germany). Inst. fuer Stroemungslehre und Stroemungsmaschinen

    2001-05-01

    Peoples running screw machines are strongly interested in a detailed theoretical analysis of the transport processes for real highly viscous liquids which are non-Newtonian in general. The paper deals with an unconventional strategy which enables to simulate the three-dimensional unsteady flow in the kneading zone of intermeshing twin-screw extruders numerically. The concept is pointed at a finite element approximation of the flow field at particular times well chosen after the computation domain has been minimized with the aid of periodicities and symmetries existing in space and time. The method has been realized numerically and proved by means of a typical kneading geometry. Selected results show that the flow and deformation processes in the kneading element differ substantially from those in a screwed segment. (orig.) [German] Es besteht ein erhebliches Interesse daran, die Transportprozesse in Schneckenmaschinen fuer reale hochviskose, nichtnewtonsche Fluessigkeiten im Detail theoretisch zu analysieren und berechenbar zu machen. In der Arbeit wird eine unkonventionelle Strategie beschrieben, nach der die dreidimensionale instationaere Stroemung im Knetbereich kaemmender Doppelschnecken numerisch simuliert werden kann. Das theoretisch fundierte Konzept zielt auf eine Finite-Elemente-Approximation des Stroemungsfelds zu gewissen Zeitpunkten, wobei das Berechnungsgebiet mit Hilfe raeumlicher und zeitlicher Periodizitaeten und Symmetrien minimiert wird. Das Konzept wurde numerisch realisiert und an einer typischen Knetgeometrie erprobt. Ausgewaehlte Ergebnisse machen deutlich, da paragraph sich die Stroemungs- und Deformationsprozesse in einem Knetelement wesentlich von denen in einem Schraubenelement gleicher Geometrie unterscheiden. (orig.)

  15. Hot-melt extrusion technology and pharmaceutical application.

    Science.gov (United States)

    Wilson, Matthew; Williams, Marcia A; Jones, David S; Andrews, Gavin P

    2012-06-01

    The use of hot-melt extrusion (HME) within the pharmaceutical industry is steadily increasing, due to its proven ability to efficiently manufacture novel products. The process has been utilized readily in the plastics industry for over a century and has been used to manufacture medical devices for several decades. The development of novel drugs with poor solubility and bioavailability brought the application of HME into the realm of drug-delivery systems. This has specifically been shown in the development of drug-delivery systems of both solid dosage forms and transdermal patches. HME involves the application of heat, pressure and agitation through an extrusion channel to mix materials together, and subsequently forcing them out through a die. Twin-screw extruders are most popular in solid dosage form development as it imparts both dispersive and distributive mixing. It blends materials while also imparting high shear to break-up particles and disperse them. HME extrusion has been shown to molecularly disperse poorly soluble drugs in a polymer carrier, increasing dissolution rates and bioavailability. The most common difficulty encountered in producing such dispersions is stabilization of amorphous drugs, which prevents them from recrystallization during storage. Pharmaceutical industrial suppliers, of both materials and equipment, have increased their development of equipment and chemicals for specific use with HME. Clearly, HME has been identified as an important and significant process to further enhance drug solubility and solid-dispersion production.

  16. Upscaling of a Batch De-Vulcanization Process for Ground Car Tire Rubber to a Continuous Process in a Twin Screw Extruder

    Directory of Open Access Journals (Sweden)

    Sitisaiyidah Saiwari

    2016-08-01

    Full Text Available As a means to decrease the amount of waste tires and to re-use tire rubber for new tires, devulcanization of ground passenger car tires is a promising process. Being an established process for NR and EPDM, earlier work has shown that for ground passenger car tire rubber with a relatively high amount of SBR, a devulcanization process can be formulated, as well. This was proven for a laboratory-scale batch process in an internal mixer, using diphenyl disulfide as the devulcanization aid and powder-sized material. In this paper, the devulcanization process for passenger car tire rubber is upscaled from 15 g per batch and transformed into a continuous process in a co-rotating twin screw extruder with a capacity of 2 kg/h. As SBR is rather sensitive to devulcanization process conditions, such as thermal and mechanical energy input, the screw design was based on a low shear concept. A granulate with particle sizes from 1–3.5 mm was chosen for purity, as well as economic reasons. The devulcanization process conditions were fine-tuned in terms of: devulcanization conditions (time/temperature profile, concentration of devulcanization aid, extruder parameters (screw configuration, screw speed, fill factor and ancillary equipment (pre-treatment, extrudate handling. The influence of these parameters on the devulcanization efficiency and the quality of the final product will be discussed. The ratio of random to crosslink scission as determined by a Horikx plot was taken for the evaluation of the process and material. A best practice for continuous devulcanization will be given.

  17. The use of rheology to elucidate the granulation mechanisms of a miscible and immiscible system during continuous twin-screw melt granulation.

    Science.gov (United States)

    Monteyne, Tinne; Heeze, Liza; Mortier, Séverine Thérèse F C; Oldörp, Klaus; Nopens, Ingmar; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

    2016-08-20

    Twin-screw hot melt granulation (TS HMG) is a valuable, but still unexplored alternative to granulate temperature and moisture sensitive drugs in a continuous way. Recently, the material behavior of an immiscible drug-binder blend during TS HMG was unraveled by using a rheometer and differential scanning calorimetry (DSC). Additionally, vibrational spectroscopic techniques proved the link between TS HMG and rheology since equal interactions at molecular level did occur in both processes. This allowed to use a rheometer to gain knowledge of the material behavior during hot melt processing of an immiscible drug-binder blend. However, miscibility of a drug-binder formulation and drug-binder interactions appear to influence the rheological properties and, hence conceivably also the granulation mechanism. The aim of this research was to examine if the TS HMG process of a miscible formulation system is comparable with the mechanism of an immiscible system and to evaluate whether rheology still serves as a useful tool to understand and optimize the hot melt granulation (HMG) process. The executed research (thermal analysis, rheological parameters and spectroscopic data) demonstrated the occurrence of a high and broad tan(δ) curve without a loss peak during the rheological temperature ramp which implies a higher material deformability without movement of the softened single polymer chains. Spectroscopic analysis revealed drug-polymer interactions which constrain the polymer to flow independently. As a result, the binder distribution step, which generally follows the immersion step, was hindered. This insight assisted the understanding of the granule properties. Inhomogeneous granules were produced due to large initial nuclei or adhesion of multiple smaller nuclei. Consequently, a higher granulation temperature was required in order to get the binder more homogeneously distributed within the granules. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. 双螺杆压缩机喷油节能改造%ENERGY SAVING TRANSFORMATION AND ANALYSIS OF TWIN-SCREW COMPRESSOR

    Institute of Scientific and Technical Information of China (English)

    于江龙; 周宝成

    2013-01-01

    The tail gas twin-screw compressor (LG77/0. 5 ) of the 600 kt/a continuous reforming PSA device in Karamay Petrochemical Company has started operation since Jan. ,2012. In order to ensure the normal operation of the liquid spray cooling unit,frequent filling of cool-ing medium (gasoline) is needed. Hence,a large amount of gasoline is consumed in the liquid spray circulation system of the unit, which causes a large energy consumption of the unit. Through analysis and tests,oil spout medium is changed. This can satisfy the normal operation of the unit and greatly reduces the energy consumption of the unit. And nearly ten million yuan can be saved each year.%克拉玛依石化分公司60万连续重整PSA装置的尾气双螺杆压缩机(LG77/0.5),自装置2011年12月开工运行后,为保证机组喷液冷却正常进行,需要从机组入口频繁补入冷却介质(汽油),故造成机组喷液循环系统消耗大量汽油,使机组能耗较大.文章通过分析、试验等方法通过改变喷油介质,在满足机组正常运行的工况下,大大降低了机组能耗,年节省费用达千万元.

  19. 挤压参数对绿豆粉糊化的影响%Effect of extrusion parameters on gelatinization of mung bean powder

    Institute of Scientific and Technical Information of China (English)

    张雁凌; 任保国

    2012-01-01

    The mung bean was used as the raw material for extruded puffing by twin screw extrusion fermentation. The effects of gelatinization degree on extruded puffing mung bean were studied. The results showed that the optimum conditions for the extruded puffing mung bean powder=the feeding rate was 110r/min,the water addition of material was 18% ,the extrusion temperature was 170℃,and the screw speed was 260r/min. The order significance of factors on the gelatinization degree was as followes=amount of adding water,puffing temperature,screw speed,the feeding rate. In this condition,the gelatinization degree of extruded puffing mung bean powder was 98.46%.%以绿豆为原料,采用双螺杆挤压膨化技术,对挤压膨化绿豆糊化进行了研究。结果表明,制备挤压膨化绿豆粉的最佳工艺条件为:喂料速度110r/min,加水量18%,膨化温度170℃,螺杆转速260r/min。影响挤压膨化绿豆粉糊化度主次顺序依次为:加水量、膨化温度、螺杆转速、喂料速度。在最佳工艺条件下,挤压膨化绿豆粉糊化度可达98.46%。

  20. Hot Melt Extrusion: Development of an Amorphous Solid Dispersion for an Insoluble Drug from Mini-scale to Clinical Scale.

    Science.gov (United States)

    Agrawal, Anjali M; Dudhedia, Mayur S; Zimny, Ewa

    2016-02-01

    The objective of the study was to develop an amorphous solid dispersion (ASD) for an insoluble compound X by hot melt extrusion (HME) process. The focus was to identify material-sparing approaches to develop bioavailable and stable ASD including scale up of HME process using minimal drug. Mixtures of compound X and polymers with and without surfactants or pH modifiers were evaluated by hot stage microscopy (HSM), polarized light microscopy (PLM), and modulated differential scanning calorimetry (mDSC), which enabled systematic selection of ASD components. Formulation blends of compound X with PVP K12 and PVP VA64 polymers were extruded through a 9-mm twin screw mini-extruder. Physical characterization of extrudates by PLM, XRPD, and mDSC indicated formation of single-phase ASD's. Accelerated stability testing was performed that allowed rapid selection of stable ASD's and suitable packaging configurations. Dissolution testing by a discriminating two-step non-sink dissolution method showed 70-80% drug release from prototype ASD's, which was around twofold higher compared to crystalline tablet formulations. The in vivo pharmacokinetic study in dogs showed that bioavailability from ASD of compound X with PVP VA64 was four times higher compared to crystalline tablet formulations. The HME process was scaled up from lab scale to clinical scale using volumetric scale up approach and scale-independent-specific energy parameter. The present study demonstrated systematic development of ASD dosage form and scale up of HME process to clinical scale using minimal drug (∼500 g), which allowed successful clinical batch manufacture of enabled formulation within 7 months.

  1. Dissolution Enhancement of Poorly Water Soluble Efavirenz by Hot Melt Extrusion Technique

    Directory of Open Access Journals (Sweden)

    Smita Kolhe

    2013-06-01

    Full Text Available Large number of drugs; including new chemical entity (NCE, are facing the solubility problem [classified as biopharmaceutical classification system (BCS Class II or IV]. Hence extensive development in solubility enhancement is required. Hot melt extrusion (HME is the most widely applied processing techniques useful for preparing granules, pellets, sustained release tablets, implants, transdermal and transmucosal drug delivery systems ,while its major advantages include enhancement of the dissolution rate and bioavailability, controlling or modifying drug release, taste masking, stabilizing the active pharmaceutical ingredient (API. Hot melt extruded dosage forms are generally complex mixtures of API, plastisizers and polymer carriers which are passed through single or twin-screw extruders at high temperature and stress, molten thermoplastic polymers during the extrusion process can function as thermal binders and/or release retardants. Present investigation deals with enhancement of dissolution rate and hence solubility of Efavirenz (Efv, which belongs to BCS class II. Efv is non neucleotide reverse transcriptase inhibitor (NNRTI for first line antiretroviral treatment type 1 with long half life of 52-56 hrs. Solubility enhancement techniques are available in wide range but HME was the preferred technique due to its several advantages. Copovidone (Kollidon VA64 as polymer and polyethylene glycol (PEG 4000, polyoxy 35 castor oil (Cremophor EL and sorbiton monolaurate (Montane 20 PHA as plasticizers were studied and optimized. Evaluation techniques like saturation solubility, effect of temperature on preparation of complexes, differential scanning calorimetry (DSC, x-ray diffraction (XRD, Infra red (IR, dissolution and in vitro permeability studies were carried out. XRD data concluded that HME process demolished the sharp peaks of Efv which indicate the complete conversion of crystal form of Efv to amorphous form. Dissolution and solubility

  2. Design on Gear Box Drive System of New Parallel Twin-screw Extruder%新型同向平行双螺杆挤出机齿轮箱传动系统的设计

    Institute of Scientific and Technical Information of China (English)

    吴志强

    2011-01-01

    介绍了同向平行双蠕杆挤出机齿轮箱传动系统的一种新型设计,输出轴传动采用功率分流式设计,使输出轴传递的扭矩提高一倍,整机的承载能力提高50%,保险系数提高30%.本设计具有结构简单、装配方便,能满足目前同向平行双螺杆挤出机对齿轮箱高扭矩,高转速的要求.%A new design of the gear box drive system of parallel twin-screw extruder was introduced. The output shaft was adopted with power split transmission to make the torque of output shaft transmission become double, make the carrying capacity of the machine increase by 50% and insurance factor increase by 30%. The design is simple in structure and easy to assemble. It can meet the requirements of parallel twin-screw extruder for high-speed and high-torque gear.

  3. Phenomenological model of maize starches expansion by extrusion

    Science.gov (United States)

    Kristiawan, M.; Della Valle, G.; Kansou, K.; Ndiaye, A.; Vergnes, B.

    2016-10-01

    During extrusion of starchy products, the molten material is forced through a die so that the sudden abrupt pressure drop causes part of the water to vaporize giving an expanded, cellular structure. The objective of this work was to elaborate a phenomenological model of expansion and couple it with Ludovic® mechanistic model of twin screw extrusion process. From experimental results that cover a wide range of thermomechanical conditions, a concept map of influence relationships between input and output variables was built. It took into account the phenomena of bubbles nucleation, growth, coalescence, shrinkage and setting, in a viscoelastic medium. The input variables were the moisture content MC, melt temperature T, specific mechanical energy SME, shear viscosity η at the die exit, computed by Ludovic®, and the melt storage moduli E'(at T > Tg). The outputs of the model were the macrostructure (volumetric expansion index VEI, anisotropy) and cellular structure (fineness F) of solid foams. Then a general model was established: VEI = α (η/η0)n in which α and n depend on T, MC, SME and E' and the link between anisotropy and fineness was established.

  4. Extrusion foaming of protein-based thermoplastic and polyethylene blends

    Science.gov (United States)

    Gavin, Chanelle; Lay, Mark C.; Verbeek, Casparus J. R.

    2016-03-01

    Currently the extrusion foamability of Novatein® Thermoplastic Protein (NTP) is being investigated at the University of Waikato in collaboration with the Biopolymer Network Ltd (NZ). NTP has been developed from bloodmeal (>86 wt% protein), a co-product of the meat industry, by adding denaturants and plasticisers (tri-ethylene glycol and water) allowing it to be extruded and injection moulded. NTP alone does not readily foam when sodium bicarbonate is used as a chemical blowing agent as its extensional viscosity is too high. The thermoplastic properties of NTP were modified by blending it with different weight fractions of linear low density polyethylene (LLDPE) and polyethylene grafted maleic anhydride (PE-g-MAH) compatibiliser. Extrusion foaming was conducted in two ways, firstly using the existing water content in the material as the blowing agent and secondly by adding sodium bicarbonate. When processed in a twin screw extruder (L/D 25 and 10 mm die) the material readily expanded due to the internal moisture content alone, with a conditioned expansion ratio of up to ± 0.13. Cell structure was non-uniform exhibiting a broad range cell sizes at various stages of formation with some coalescence. The cell size reduced through the addition of sodium bicarbonate, overall more cells were observed and the structure was more uniform, however ruptured cells were also visible on the extrudate skin. Increasing die temperature and introducing water cooling reduced cell size, but the increased die temperature resulted in surface degradation.

  5. Study of glue extrusion after endoscopic N-butyl-2-cyanoacrylate injection on gastric variceal bleeding

    Institute of Scientific and Technical Information of China (English)

    Yan-Mei Wang; Liu-Fang Cheng; Nan Li; Kai Wu; Jun-Shan Zhai; Ya-Wen Wang

    2009-01-01

    AIM: To investigate glue extrusion after endoscopic N-butyl-2-cyanoacrylate injection on gastric variceal bleeding and to evaluate the long-term efficacy and safety of this therapy.METHODS: A total of 148 cirrhotic patients in our hospital with esophagogastric variceal bleeding (EGVB) were included in this study. N-butyl-2-cyanoacrylate was mixed with lipiodol in a 1:1 ratio and injected as a bolus of 1-3 mL according to variceal size. Patients underwent endoscopic follow-up the next week, fourth week, second month, fourth month, and seventh month after injection and then every 6 mo to determine the cast shape. An abdominal X-ray film and ultrasound or computed tomographic scan were also carried out in order to evaluate the time of variceal disappearance and complete extrusion of the cast. The average follow-up time was 13.1 mo.RESULTS: The instantaneous hemostatic rate was 96.2%. Early re-bleeding after injection in 9 cases (6.2%) was estimated from rejection of adhesive. Late re-bleeding occurred in 12 patients (8.1%) at 2-18 mo. The glue cast was extruded into the lumen within one month in 86.1% of patients and eliminated within one year. Light erosion was seen at the injection position and mucosa edema in the second week. The glue casts were extruded in 18 patients (12.1%) after one week and in 64 patients (42.8%) after two weeks. All kinds of glue clumping shapes and colors on endoscopic examination were observed in 127 patients (86.1%) within one month, including punctiform, globular, pillar and variform. Forty one patients (27.9%) had glue extrusion after 3 mo and 28 patients (28.9%) after six months. The extrusion time was not related to the injection volume of histoacryl. Obliteration was seen in 70.2% (104 cases) endoscopically. The main complication was re-bleeding resulting from extrusion. The prognosis of the patients depended on the severity of the underlying liver disease.CONCLUSION: Endoscopic injection of cyanoacrylate is highly effective for

  6. THE MODELING OF COUNTER-ROTATING TWIN-SCREW EXTRUDERS AS REACTORS FOR SINGLE-COMPONENT REACTIONS

    NARCIS (Netherlands)

    GANZEVELD, KJ; CAPEL, JE; VANDERWAL, DJ; JANSSEN, LPBM

    1994-01-01

    Numerical models are useful to study the behaviour of the extruder as a polymerization reactor. With a correct numerical model a theoretical analysis of the influence of several reaction and extruder parameters can be made, the limitations of the use of the extruder reactor can be determined and the

  7. THE MODELING OF COUNTER-ROTATING TWIN-SCREW EXTRUDERS AS REACTORS FOR SINGLE-COMPONENT REACTIONS

    NARCIS (Netherlands)

    GANZEVELD, KJ; CAPEL, JE; VANDERWAL, DJ; JANSSEN, LPBM

    Numerical models are useful to study the behaviour of the extruder as a polymerization reactor. With a correct numerical model a theoretical analysis of the influence of several reaction and extruder parameters can be made, the limitations of the use of the extruder reactor can be determined and the

  8. A Comprehensive Study on Classification of Passive Intrusion and Extrusion Detection System

    Directory of Open Access Journals (Sweden)

    A.Kalaivani

    2013-05-01

    Full Text Available Cyber criminals compromise Integrity, Availability and Confidentiality of network resources in cyber space and cause remote class intrusions such as U2R, R2L, DoS and probe/scan system attacks .To handle these intrusions, Cyber Security uses three audit and monitoring systems namely Intrusion Prevention Systems (IPS, Intrusion Detection Systems (IDS. Intrusion Detection System (IDS monitors only inbound traffic which is insufficient to prevent botnet systems. A system to monitor outbound traffic is named as Extrusion Detection System (EDS. Therefore a hybrid system should be designed to handle both inbound and outbound traffic. Due to the increased false alarms preventive systems do not suite to an organizational network. The goal of this paper is to devise a taxonomy for cyber security and study the existing methods of Intrusion and Extrusion Detection systems based on three primary characteristics. The metrics used to evaluate IDS and EDS are also presented.

  9. Reprocessability of PHB in extrusion: ATR-FTIR, tensile tests and thermal studies

    Directory of Open Access Journals (Sweden)

    Leonardo Fábio Rivas

    Full Text Available Abstract Mechanical recycling of biodegradable plastics has to be encouraged, since the consumption of energy and raw materials can be reduced towards a sustainable development in plastics materials. In this study, the evolution of thermal and mechanical properties, as well as structural changes of poly(hydroxybutyrate (PHB up to three extrusion cycles were investigated. Results indicated a significant reduction in mechanical properties already at the second extrusion cycle, with a reduction above 50% in the third cycle. An increase in the crystallinity index was observed due to chemicrystallization process during degradation by chain scission. On the other hand, significant changes in the chemical structure or in thermal stability of PHB cannot be detected by Fourier transform infrared spectroscopy (FTIR and thermogravimetric analyses (TGA, respectively.

  10. Effect of extrusion ratio on coating extrusion of Pb-GF composite wire by numerical simulation and experimental investigation

    Institute of Scientific and Technical Information of China (English)

    WANG Xin; SUN Hong-fei; FANG Wen-bin

    2009-01-01

    The extrusion ratio is one of the key parameters for manufacturing the lead-glass fiber (Pb-GF) composite wire by coating extrusion. The effect of extrusion ratio on coating extrusion of Pb-GF composite wire was studied by finite element numerical simulation with the use of the DEFOEM simulation software. The simulation result shows that the higher the extrusion ratio, the higher the effective stress that the glass fiber bears during extrusion. It is also observed that the extrusion force increases with the increase of the extrusion ratio. The extrusion experiment of Pb-GF composite wire reveals that extrusion ratio is changed by changing the quantity of glass fiber and composite diameter. The rule that increasing the extrusion ratio enhances the coating speed limit suggests that the load on the glass fiber increases with increasing extrusion ratio. Both the simulation and the extrusion experiments show that the extrusion force increases with increasing extrusion ratio.

  11. Rheological study of the mixture of acetaminophen and polyethylene oxide for hot-melt extrusion application.

    Science.gov (United States)

    Suwardie, Herman; Wang, Peng; Todd, David B; Panchal, Viral; Yang, Min; Gogos, Costas G

    2011-08-01

    There is a growing interest of extrusion drug and polymer together to manufacture various solid dosages. In those cases, the drug's release profiles are greatly affected by the miscibility of two materials. The goal of this study is to test the drug's solubility in molten polymer and obtain the mixture's rheological properties for the purpose of optimizing the extrusion process. The dynamic and steady viscosities of APAP-PEO mixture were determined using oscillatory and capillary rheometers. The curves of viscosity vs. drug loading generally have a "V" shape, and the minimal point gives the APAP's solubility in PEO. The test results suggest that different dynamic methods lead to essentially the same solubility data. At high shear rates, the mixtures show shear thinning behavior and the viscosity becomes less sensitive to the drug loading. In other words, it is desirable to use a low shear rate in order to deduce the drug's solubility in polymer from the viscosity data. On the other hand, viscosity data at high shear rates are more representative of the materials' rheological properties during extrusion.

  12. Apical extrusion of debris by supplementary files used for retreatment: An ex vivo comparative study

    Directory of Open Access Journals (Sweden)

    Ajinkya M Pawar

    2016-01-01

    Full Text Available Aim: This study evaluated whether using supplementary files for removing root canal filling residues after ProTaper Universal Retreatment files (RFs increased the debris extrusion apically. Materials and Methods: Eighty mandibular premolars with single root and canal were instrumented with ProTaper Universal rotary system (SX-F3 and obturated. The samples were divided randomly into four groups (n = 20. Group 1 served as a control; only ProTaper Universal RFs D1-D3 were used, and the extruded debris was weighed. Groups 2, 3, and 4 were the experimental groups, receiving a twofold retreatment protocol: Removal of the bulk, followed by the use of supplementary files. The bulk was removed by RFs, followed by the use of ProTaper NEXT (PTN, WaveOne (WO, and Self-Adjusting File (SAF for removal of the remaining root filling residues. Debris extruded apically were weighed and compared to the control group. Statistical analysis was performed using one-way analysis of variance (ANOVA and post hoc Tukey′s test. Results: All the three experimental groups presented significant difference (P < .01. The post hoc Tukey′s test confirmed that Group 4 (SAF exhibited significantly less (P < .01 debris extrusion between the three groups tested. Conclusion: SAF results in less extrusion of debris when used as supplementary file to remove root-filling residues, compared to WO and PTN.

  13. GRAPHITE EXTRUSIONS

    Science.gov (United States)

    Benziger, T.M.

    1959-01-20

    A new lubricant for graphite extrusion is described. In the past, graphite extrusion mixtures have bcen composed of coke or carbon black, together with a carbonaceous binder such as coal tar pitch, and a lubricant such as petrolatum or a colloidal suspension of graphite in glycerin or oil. Sinee sueh a lubricant is not soluble in, or compatible with the biiider liquid, such mixtures were difficult to extrude, and thc formed pieees lacked strength. This patent teaches tbe use of fatty acids as graphite extrusion lubricants and definite improvemcnts are realized thereby since the fatty acids are soluble in the binder liquid.

  14. Update on Fabrication of Extrusions for TREAT Trade Study

    Energy Technology Data Exchange (ETDEWEB)

    Luther, Erik Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Leckie, Rafael M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dombrowski, David E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Papin, Pallas A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-03-05

    This supplemental report describes fuel fabrication efforts conducted for the Idaho National Laboratory Trade Study for the TREAT Conversion project that is exploring the replacement of the HEU (Highly Enriched Uranium) fuel core of the TREAT reactor with LEU (Low Enriched Uranium) fuel. Previous reports have documented fabrication of fuel by the “upgrade” process developed at Los Alamos National Laboratory. These experiments supplement an earlier report that describes efforts to increase the graphite content of extruded fuel and minimize cracking.

  15. Simulation analysis and experiment of temperature rising characteristics in twin-screw extruder%双螺杆挤压膨化机温升特性的仿真分析与试验

    Institute of Scientific and Technical Information of China (English)

    林江娇; 赵春芳; 朱立学

    2012-01-01

    为了分析双螺杆挤压膨化机内流体的温度变化过程及规律,该文利用流变学理论建立了非等温、非牛顿流体的数学模型,在螺杆转速为245 r/min,入口处压力为0.5 MPa时,分别取初始温度423 K,433 K和443 K条件下,以玉米为原料对流体的温度分布进行了仿真分析.分析结果表明:流体受挤压过程中温度上升了5K左右,其中啮合区升温较快,初始温度为423 K时流体的温度分布较均匀;3种初始温度条件下物料均以等温状态流出挤压膨化模头,并通过食品膨化试验验证了仿真结论.研究结果可为双螺杆挤压膨化加工提供参考.%To explore the fluid temperature change law of twin screw extruder, a fluid-temperature coupling model of non-isothermal Newton fluid was constructed based on the rheology theory. The temperature distribution discipline of fluid in the extruder was simulated with the initial temperature T at 423, 433 and 443 K, respectively. Results showed that the fluid temperature increased by 5 K, high temperature circle in meshing district expanded quickly. The fluid temperature was changed uniformly at the beginning of the screw extruder, then the fluid flow exited out of the extruder isothermally. Several optimum product conditions of twin screw extruder were verified with food expanding experiments. This research could provide references for twin screw extruder processing.

  16. Study and automatic control of the ceramic tile extrusion operation; Estudio y control automatico de la operacion de extrusion de baldosas ceramicas

    Energy Technology Data Exchange (ETDEWEB)

    Aguilella, M.; Foucard, L.; Mallol, G.; Sanchez, M. J.; Lopez, M.; Benasges, R.

    2012-07-01

    The ever-larger tile sizes demanded by the market, the higher quality requirements, and the increasingly similar installation to that of pressed products make it necessary to narrow the tolerance limits of final extruded tile size in order to maintain the products competitiveness. The results of this study show that, though mixing water has a great influence on drying shrinkage, it hardly affects extruded tile firing shrinkage. This indicates that control of the water added in the extrusion process is indispensable in order avoid variations in drying shrinkage and, thus, to assure good dimensional stability of the end product. (Author)

  17. Apical Extrusion of Irrigants in Immature Permanent Teeth by Using EndoVac and Needle Irrigation: An In Vitro Study.

    Directory of Open Access Journals (Sweden)

    N Velmurugan

    2014-08-01

    Full Text Available Immature teeth have a large apical opening and thin divergent or parallel dentinal walls; hence, with conventional needle irrigation there is a very high possibility of extrusion. This study was done to compare the apical extrusion of NaOCl in an immature root delivered using EndoVac and needle irrigation.Eighty freshly extracted maxillary central incisors were decoronated followed by access cavity preparation. Modified organotypic protocol was performed to create an open apex; then, the samples were divided into four groups (n=20: EndoVac Microcannula (group I, EndoVac Macrocannula (group II, NaviTip irrigation needle (group III and Max-i-Probe Irrigating needle (group IV; 9.0 ml of 3% sodium hypochlorite was delivered slowly over a period of 60 seconds. Extruded irrigants were collected in a vial and analysed statistically.Group I, group III and group IV showed 100% extrusion (20/20 but group II showed only 40% extrusion (8/20. The difference in this respect between group II and other groups was statistically significant (P<0.001. With regards to the volume of extrusion, group II had only 0.23 ml of extruded irrigant. Group I extruded 7.53ml of the irrigant. Group III and group IV extruded the entire volume of irrigant delivered.EndoVac Macrocannula resulted in the least extrusion of irrigant in immature teeth when compared to EndoVac Microcannula and conventional needle irrigation.

  18. Suitability assessment of a continuous process combining thermo-mechano-chemical and bio-catalytic action in a single pilot-scale twin-screw extruder for six different biomass sources.

    Science.gov (United States)

    Vandenbossche, Virginie; Brault, Julien; Hernandez-Melendez, Oscar; Evon, Philippe; Barzana, Eduardo; Vilarem, Gérard; Rigal, Luc

    2016-07-01

    A process has been validated for the deconstruction of lignocellulose on a pilot scale installation using six types of biomass selected for their sustainability, accessibility, worldwide availability, and differences of chemical composition and physical structure. The process combines thermo-mechano-chemical and bio-catalytic action in a single twin-screw extruder. Three treatment phases were sequentially performed: an alkaline pretreatment, a neutralization step coupled with an extraction-separation phase and a bioextrusion treatment. Alkaline pretreatment destructured the wall polymers after just a few minutes and allowed the initial extraction of 18-54% of the hemicelluloses and 9-41% of the lignin. The bioextrusion step induced the start of enzymatic hydrolysis and increased the proportion of soluble organic matter. Extension of saccharification for 24h at high consistency (20%) and without the addition of new enzyme resulted in the production of 39-84% of the potential glucose.

  19. The thermo-mechano-chemical twin-screw reactor, a new perspective for the biorefinery of sunflower whole plant: aqueous extraction of oil and other biopolymers, and production of biodegradable fiberboards from cake

    Directory of Open Access Journals (Sweden)

    Evon Philippe

    2016-09-01

    Full Text Available Biorefinery of sunflower whole plant was performed successfully using a thermo-mechano-chemical twin-screw reactor. This led to the aqueous extraction of oil and other biopolymers like proteins, pectins and non pectic sugars. It resulted in the overall fractionation of biomass, thus allowing a complete valorization of the input. This biorefinery process was not only efficient but it was also environment-friendly. In addition, it contributed to the production of different end products for various industrial applications. Firstly, the hydrophilic phase will be recycled to the process. Secondly, the densest oil-in-water emulsion is a promising candidate for the formulation of cosmetic creams. Thirdly, the upper hydrophobic phase will be usable for the waterproofing treatment of the surface of agromaterials by coating. Its demixing will also lead to the production of proteins with tensioactive properties. These will serve for the food industry. Lastly, the cake was a mixture of plasticized proteins and lignocellulosic fibers. It was thus considered as a natural composite. Its molding into cohesive fiberboards was conducted successfully using both thermopressing and compression molding processes. The self-bonded boards with high density will be suitable for use as load bearing boards in dry conditions (floor underlayers, interior partitions, furniture, etc.. Positioned in walls and ceilings, boards with medium and low density will contribute to the heat insulation of buildings. In addition, the bulk cake will be also usable as a loose fill insulation material. As proposed, this flow chart thus allows a valorization for all fractions originating from the twin-screw reactor.

  20. Nerva Fuel Element Development Program Summary Report - July 1966 through June 1972 Extrusion Studies

    Energy Technology Data Exchange (ETDEWEB)

    Napier, J. M.

    1973-09-21

    This part of the completion report pertaining to the NERVA graphite fuel element program covers data collected during the extrusion studies. The physical properties of the fuel element reached the following values: coefficient of thermal expansion (CTE) - 7.0 x 10-6/o C (25 - l,OOOo C); modulus of elasticity - 1.5 x lo6 psi; flexural strength - - 8,000 psi; ultimate strain to failure - 5,500 pidin; good thermal stress resistance. Matrices were produced which could be vapor coated with crack-free films of zirconium carbide. The CTE of the matrix was almost equal to the CTE of the zirconium carbide coating.

  1. Effect of storage temperatures on injured escherichia coli cell populations in whey and corn meal snacks treated with a twin screw extruder

    Science.gov (United States)

    The effect of extrusion treatment parameters on injured populations of corn meal and whey protein isolate inoculated with surrogate E. coli populations has been reported. However, information on the effect of treatment parameters on injured bacterial populations of treated corn and whey protein prod...

  2. 挤压对南极磷虾渣中脂质留存的影响%Effect of Extrusion on the Lipids Retained in the Solid of Antarctic Krill Extrudates

    Institute of Scientific and Technical Information of China (English)

    刘志东; 陈雪忠; 陈勇; 曲映红; 欧阳杰; 刘勤; 马庆保; 黄洪亮

    2016-01-01

    Antarctic krill (Euphausia Superba) is paid more attention for its large biomass, better nutritional and functional properties in recent years. Study demonstrated that Antarctic krill lipid differs from other dietary sources of omega-3 in that it contains a relatively high amount of omega-3 fatty acids linked with phospholipids. In order to exploring the feasibility of twin-screw extrusion used in unit processing of Antarctic krill, a compara-tive study was conducted in this paper on changes of the content and composition of lipids in Antarctic krill (heat treated and unheat treated) before and after extrusion. Experimental results showed that change of the lipid content in the extruded Antarctic krill 1.74%without heat treatment was less than the change of lipid con-tent in the extruded Antarctic krill 4.16%with heat treatment. The total content of saturated fatty acid decreased. The total content of monosaturated fatty acid was relatively stable. The total content of polysaturated fatty acid decreased. The omega-6 polysaturated fatty acid increased. In conclusion, twin-screw extrusion had a great in-fluence on the lipid content and composition in the solid of extruded Antarctic krill, had a greater influence on that of heat treated Antarctic krill extruded, especially.%南极磷虾因其巨大的生物资源量,良好的营养和功能特性受到广泛关注。比较未经热处理南极磷虾和经热处理南极磷虾采用双螺杆挤压前后脂质含量和组成的变化,探索双螺杆挤压技术应用于南极磷虾单元加工的可行性。研究发现,两种处理方法的南极磷虾经过双螺杆挤压处理后,其饱和脂肪酸总含量减少,单不饱和脂肪酸总含量相对稳定,ω-3多不饱和脂肪酸总含量减少,ω-6多不饱和脂肪酸总含量增加。未经热处理的南极磷虾挤压前后脂质含量的变化1.74%小于经过热处理的南极磷虾挤压前后的脂质含量4.16%。试验结果表明,双螺

  3. Food extrusion.

    Science.gov (United States)

    Harper, J M

    1978-01-01

    Extrusion processing has become an important food process in the manufacture of pasta, ready-to-eat cereals, snacks, pet foods, and textured vegetable protein (TVP). An extruder consists of tightly fitting screw rotating within a stationary barrel. Preground and conditioned ingredients enter the screw where they are conveyed, mixed, and heated by a variety of processes. The product exits the extruder through a die where it usually puffs and changes texture from the release of steam and normal forces. Mathematical models for extruder flow and torque have been found useful in describing exclusion operations. Scale-up can be facilitated by the application of these models. A variety of food extruder designs have developed. The differences and similarity of design are discussed. Pertinent literature on the extrusion of cereal/snack products, full-fat soy, TVP, pet foods (dry and semi-moist), pasta, and beverage or other food bases are discussed. In many of these applications, the extruder is a high temperature, short time process which minimizes losses in vitamins and amino acids. Color, flavor, and product shape and texture are also affected by the extrusion process. Extrusion has been widely applied in the production of nutritious foods. Emphasis is placed on the use of extrusion to denature antinutritional factors and the improvement of protein quality and digestibility.

  4. Morphological studies on block copolymer modified PA 6 blends

    Science.gov (United States)

    Poindl, M.; Bonten, C.

    2014-05-01

    Recent studies show that compounding polyamide 6 (PA 6) with a PA 6 polyether block copolymers made by reaction injection molding (RIM) or continuous anionic polymerization in a reactive extrusion process (REX) result in blends with high impact strength and high stiffness compared to conventional rubber blends. In this paper, different high impact PA 6 blends were prepared using a twin screw extruder. The different impact modifiers were an ethylene propylene copolymer, a PA PA 6 polyether block copolymer made by reaction injection molding and one made by reactive extrusion. To ensure good particle matrix bonding, the ethylene propylene copolymer was grafted with maleic anhydride (EPR-g-MA). Due to the molecular structure of the two block copolymers, a coupling agent was not necessary. The block copolymers are semi-crystalline and partially cross-linked in contrast to commonly used amorphous rubbers which are usually uncured. The combination of different analysis methods like atomic force microscopy (AFM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) gave a detailed view in the structure of the blends. Due to the partial cross-linking, the particles of the block copolymers in the blends are not spherical like the ones of ethylene propylene copolymer. The differences in molecular structure, miscibility and grafting of the impact modifiers result in different mechanical properties and different blend morphologies.

  5. Morphological studies on block copolymer modified PA 6 blends

    Energy Technology Data Exchange (ETDEWEB)

    Poindl, M., E-mail: marcus.poindl@ikt.uni-stuttgart.de, E-mail: christian.bonten@ikt.uni-stuttgart.de; Bonten, C., E-mail: marcus.poindl@ikt.uni-stuttgart.de, E-mail: christian.bonten@ikt.uni-stuttgart.de [Institut für Kunststofftechnik, University of Stuttgart (Germany)

    2014-05-15

    Recent studies show that compounding polyamide 6 (PA 6) with a PA 6 polyether block copolymers made by reaction injection molding (RIM) or continuous anionic polymerization in a reactive extrusion process (REX) result in blends with high impact strength and high stiffness compared to conventional rubber blends. In this paper, different high impact PA 6 blends were prepared using a twin screw extruder. The different impact modifiers were an ethylene propylene copolymer, a PA PA 6 polyether block copolymer made by reaction injection molding and one made by reactive extrusion. To ensure good particle matrix bonding, the ethylene propylene copolymer was grafted with maleic anhydride (EPR-g-MA). Due to the molecular structure of the two block copolymers, a coupling agent was not necessary. The block copolymers are semi-crystalline and partially cross-linked in contrast to commonly used amorphous rubbers which are usually uncured. The combination of different analysis methods like atomic force microscopy (AFM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) gave a detailed view in the structure of the blends. Due to the partial cross-linking, the particles of the block copolymers in the blends are not spherical like the ones of ethylene propylene copolymer. The differences in molecular structure, miscibility and grafting of the impact modifiers result in different mechanical properties and different blend morphologies.

  6. Leavened dough processing by supercritical fluid extrusion (SCFX).

    Science.gov (United States)

    Hicsasmaz, Zeynep; Dogan, Esref; Chu, Cindy; Rizvi, Syed S H

    2003-10-08

    Yeast-leavened dough processing is semicontinuous due to the requirement for fermentation at constant temperature and humidity. Also, new regulations on the emission of alcohols are becoming burdensome on the baking industry. Extrusion processing of dough with supercritical carbon dioxide (SC-CO(2)) is envisioned to alleviate emission problems and to decrease production time by eliminating fermentation. A bread dough formulation with 50% (w/w) moisture was leavened by injecting 1.5% (w/w) SC-CO(2) in a twin-screw extruder at 37 degrees C. Specific mechanical energy input was 260 kJ/kg. The operating apparent shear rate range was 60-260 s(-1). SCFX-leavened dough density (420-430 kg/m(3)) was in good agreement with values reported for similar doughs. The flow behavior index, obtained by an on-line slit rheometer, was 0.49 for the nonleavened control and 0.63 for the SCFX-leavened dough. Apparent viscosity of the SCFX-leavened dough varied from 37 to 23 Pa-s. This new continuous process offers attractive possibilities for industrial applications if further developed.

  7. Apical Extrusion of Irrigants in Immature Permanent Teeth by Using EndoVac and Needle Irrigation: An In Vitro Study

    Science.gov (United States)

    Velmurugan, N; Sooriaprakas, C; Jain, Preetham

    2014-01-01

    Objective: Immature teeth have a large apical opening and thin divergent or parallel dentinal walls; hence, with conventional needle irrigation there is a very high possibility of extrusion. This study was done to compare the apical extrusion of NaOCl in an immature root delivered using EndoVac and needle irrigation. Materials and Methods: Eighty freshly extracted maxillary central incisors were decoronated followed by access cavity preparation. Modified organotypic protocol was performed to create an open apex; then, the samples were divided into four groups (n=20): EndoVac Microcannula (group I), EndoVac Macrocannula (group II), NaviTip irrigation needle (group III) and Max-i-Probe Irrigating needle (group IV); 9.0 ml of 3% sodium hypochlorite was delivered slowly over a period of 60 seconds. Extruded irrigants were collected in a vial and analysed statistically. Results: Group I, group III and group IV showed 100% extrusion (20/20) but group II showed only 40% extrusion (8/20). The difference in this respect between group II and other groups was statistically significant (Pirrigant. Group I extruded 7.53ml of the irrigant. Group III and group IV extruded the entire volume of irrigant delivered. Conclusion: EndoVac Macrocannula resulted in the least extrusion of irrigant in immature teeth when compared to EndoVac Microcannula and conventional needle irrigation. PMID:25584055

  8. 3D Numerical study on the hollow profile polymer extrusion forming based on the gas-assisted technique

    Science.gov (United States)

    Ren, Z.; Huang, X. Y.; Liu, H. S.

    2016-07-01

    In this study, gas-assisted extrusion method was introduced into the extrusion of the hollow profiles. To validate the feasibility of the new extrusion method, 3D numerical simulation of the hollow profiles based on gas-assisted technique was carried out by using the finite element method. The Phan-Thien-Tanner (PTT) mode was selected as the construction equation. In the simulations, the physical field distributions of four different extrusion modes were obtained and analyzed. Results showed that the extrudate effect of traditional no gas- assisted mode was poor because the extrudate swell phenomenon is obvious and the physical field values are larger. For the gas-assisted of the inner wall, the extrudate swell of the melt was more obvious than that of the traditional no gas-assisted mode on account of the no-slip boundary condition on the outer wall. For the gas-assisted of the outer wall, the dimple effect of the inner wall is more obvious owing to the no-slip boundary condition on the inner wall. However, the extrusion effect of the double walls gas-assisted mode is very good because of the full-slip effect on the both walls.

  9. Optimization of Process for Rice Noodle Direct Extruded by Twin-Screw Extruder%直接挤出制备米粉(线)工艺的优化

    Institute of Scientific and Technical Information of China (English)

    安红周; 范运乾; 豆洪启; 杨波涛; 张瑞莉; 李盘欣

    2012-01-01

    为了获得直接挤压制备米粉(线)的最适工艺参数,采用响应面(RSM)方法设计试验方案,对挤压机挤压制作米粉的工艺参数进行优化分析.研究原料含水量、机筒温度、螺杆转速对米粉糊化度的影响.结果表明:3个因素对糊化度影响大小依次为机筒Ⅲ区温度>螺杆转速>原料含水量.通过响应面分析得出挤压米粉最佳工艺:原料含水量35.1%,Ⅲ区温度102℃,螺杆转速117r/min.在此条件下,米粉糊化度为92.1.与3种市售产品对比,自制米粉在硬度、糊化度、咀嚼性和感官品质方面达到了市售产品平均水平.%Optimized process for direct extruded rice noodles which designed by the Response Surface Methodology (RSM) was studied by evaluate effect of extrusion process parameters (feed moisture content, barrel temperature, and screw speed) on gelatinization degree and sensory scoring of rice extrudate. The result indicated that the effect order of four factors on gelatinization degree was as follows: barrel temperature, screw speed, feed moisture content. The canonical analysis revealed that optimal conditions for processing of direct extruded rice noodles were: feed moisture content 35.1% ,barrel temperature 102℃,screw speed 117r/min. Under optimal conditions, the gelatinization degree of rice noodles was 92. 1. Compared with 3 varieties of commercial products, trial product has the similar hardness, gelatinization, chewiness and sensory evaluation.

  10. Processing of Copper by Hydrostatic ExtrusionStudies of Microstructure and Properties

    Directory of Open Access Journals (Sweden)

    Leszczyńska-Madej B.

    2016-09-01

    Full Text Available The present study attempts to apply HE to 99.99% pure copper. The microstructure of the samples was investigated by both light microscopy and scanning transmission electron microscopy (STEM. Additionally, the microhardness was measured, the tensile test was made, and statistical analysis of the grains and subgrains was performed. Based on Kikuchi diffraction patterns, misorientation was determined. The obtained results show that microstructure of copper deformed by hydrostatic extrusion (HE is rather inhomogeneous. The regions strongly deformed with high dislocation density exist near cells and grains/subgrains free of dislocations. The measurements of the grain size have revealed that the sample with an initial in annealed-state grain size of about 250 μm had this grain size reduced to below 0.35μm when it was deformed by HE to the strain ε=2.91. The microhardness and UTS are stable within the whole investigated range of deformation.

  11. The interplay between subduction and lateral extrusion : A case study for the European Eastern Alps based on analogue models

    NARCIS (Netherlands)

    van Gelder, I. E.; Willingshofer, E.; Sokoutis, D.; Cloetingh, S. A.P.L.

    2017-01-01

    A series of analogue experiments simulating intra-continental subduction contemporaneous with lateral extrusion of the upper plate are performed to study the interference between these two processes at crustal levels and in the lithospheric mantle. The models demonstrate that intra-continental

  12. Study and development of nanocomposites PBT/bentonite clay treated by ionizing radiation: preparation and characterization; Estudo e desenvolvimento de nanocompositos PBT/argila bentonita tratados por radiacao ionizante: preparacao e caracterizacao

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, Mariana do Nascimento

    2014-07-01

    This work describes the preparation and characterization of composites based on poly (butylene terephthalate) - PBT and brazilian modified clay prepared by the melt intercalation. PBT nanocomposites with 3 and 5 % by weight of organically modified clay, by the addition of a quaternary ammonium salt, were prepared by extrusion using a twin-screw extruder machine. After the extrusion process, the materials were injected to obtain specimens tests samples for the characterization tests. Part of the specimens samples were irradiated using an electron beam accelerator with 1.5 MeV at room temperature in the presence of air. Samples of pure PBT and irradiated and non-irradiated nanocomposites were characterized by mechanical tests of tensile, flexural and impact, heat distortion temperature (HDT), X - ray diffraction (XRD), scanning electron microscopy (SEM), melt flow index (MFI) thermogravimetry (TG) and differential scanning calorimetry (DSC) and the correlation between the properties was discussed. The results showed that the addition of clay, in both percentages, promoted an increase greater than 50 % in tensile strength at break and a gain of around 35% in heat distortion temperature when compared to the pure polymer. The treatment with ionizing radiation of electron beam at the doses used in this study showed no significant changes in material properties. (author)

  13. The Acetylation of Starch by Reactive Extrusion

    NARCIS (Netherlands)

    Graaf, Robbert A. de; Broekroelofs, Annet; Janssen, Léon P.B.M.

    1998-01-01

    Potato starch has been acetylated in a counter rotating twin screw extruder using vinylacetate and sodium hydroxide. The desired starch acetylation reaction is accompanied by an undesired parallel base catalysed hydrolysis reaction of vinylacetate and a consecutive hydrolysis reaction of the acetyla

  14. Assessment of extrusion-sonication process on flame retardant polypropylene by rheological characterization

    Directory of Open Access Journals (Sweden)

    Guadalupe Sanchez-Olivares

    2016-05-01

    Full Text Available In this work, the rheological behavior of flame retardant polypropylene composites produced by two methods: 1 twin-screw extrusion and 2 ultrasound application combined with a static mixer die single-screw extrusion is analyzed in detail; results are related to the morphology of the composites. The flame retardant polymer composites are composed of a polypropylene matrix, an intumescent flame retardant system and functionalized clay. Scanning electron microscopy revealed that the combination of the static mixer die and on-line sonication reduced particle size and improved the dispersion and distribution of the intumescent additives in the polypropylene matrix at the micrometric level. From linear viscoelastic properties, the Han, Cole-Cole and van Gurp-Palmen diagrams characterized the improved particle dispersion of the flame retardant additives. Two well-defined rheological behaviors were observed in these diagrams. These behaviors are independent on clay presence and concentration. In fact, the ultrasound device generates a 3D highly interconnected structure similar to a co-continuous pattern observed in polymer blends as evidenced by rheological measurements. This improvement in the dispersion and distribution of the additives is attributed to the combined effect of the static mixer die and on-line sonication that allowed reducing the additive content while achieving the optimum classification UL94-V0.

  15. Conica Counter-rotation Twin-Screws Extrusion for Solid Propellants and explosiv%锥形异向旋转双螺杆在火炸药行业中的应用

    Institute of Scientific and Technical Information of China (English)

    张红霞; 程春扬

    2012-01-01

    在国外,火炸药行业所用的双螺杆设备都是组合式同向旋转双螺杆.然而,通过理论分析和实践证明,锥形异向旋转双螺杆更适宜用于火炸药加工,它不仅能满足火炸药的高扭矩、高机头压力的特殊需求,而且安全性也大有提高.在高分子材料加工中,易分解的聚氯乙烯也常用异向旋转双螺杆.本文介绍了异向旋转双螺杆的结构,论述了它的工作原理和讨论了安全性,列出了实验数据,证实锥形异向旋转双螺杆用于火炸药行业是可行的.本文还提出这种设备的进一步改进措施.

  16. Fusion processing of itraconazole solid dispersions by kinetisol dispersing: a comparative study to hot melt extrusion.

    Science.gov (United States)

    DiNunzio, James C; Brough, Chris; Miller, Dave A; Williams, Robert O; McGinity, James W

    2010-03-01

    KinetiSol Dispersing (KSD) is a novel high energy manufacturing process investigated here for the production of pharmaceutical solid dispersions. Solid dispersions of itraconazole (ITZ) and hypromellose were produced by KSD and compared to identical formulations produced by hot melt extrusion (HME). Materials were characterized for solid state properties by modulated differential scanning calorimetry and X-ray diffraction. Dissolution behavior was studied under supersaturated conditions. Oral bioavailability was determined using a Sprague-Dawley rat model. Results showed that KSD was able to produce amorphous solid dispersions in under 15 s while production by HME required over 300 s. Dispersions produced by KSD exhibited single phase solid state behavior indicated by a single glass transition temperature (T(g)) whereas compositions produced by HME exhibited two T(g)s. Increased dissolution rates for compositions manufactured by KSD were also observed compared to HME processed material. Near complete supersaturation was observed for solid dispersions produced by either manufacturing processes. Oral bioavailability from both processes showed enhanced AUC compared to crystalline ITZ. Based on the results presented from this study, KSD was shown to be a viable manufacturing process for the production of pharmaceutical solid dispersions, providing benefits over conventional techniques including: enhanced mixing for improved homogeneity and reduced processing times.

  17. Study on Hot Deformation Behavior of 7085 Aluminum Alloy during Backward Extrusion Process

    Directory of Open Access Journals (Sweden)

    R. B. Mei

    2015-01-01

    Full Text Available Compression test was carried out and the true stress-strain curves were obtained from the hot compression of 7085 alloy. A numerical simulation on the deformation behavior of 7085 aluminum alloy during the backward extrusion was also performed by finite element method. The results show that dynamic recrystallization occurs in the hot compression of 7085 alloy and the peak stress reaches higher values as the strain rate increases and deformation temperature decreases. The backward extrusion processes include contact deformation, initial deformation, and steady deformation. Severe plastic deformation of shear and compression occurs when the metal flowed into the channel between fillet of punch and wall of die so that the grain size can be refined by backward extrusion. The deformation in the region of top of wall is too small to meet the mechanical properties of requirements and the metal usually needs to be trimmed. The experiments with the same parameters as simulation had been carried out and the experimental cup after extrusion has better quality.

  18. Study of Microstructure and Mechanical Properties Effects on Workpiece Quality in Sheet Metal Extrusion Process

    Directory of Open Access Journals (Sweden)

    Chatkaew Suriyapha

    2015-01-01

    Full Text Available Sheet metal extrusion is a metal forming process in which the movement of a punch penetrates a sheet metal surface and it flows through a die orifice; the extruded parts can be deflected to have an extrusion cavity and protrusion on the opposite side. Therefore, this process results in a narrow region of highly localized plastic deformation due to the formation and microstructure effect on the work piece. This research investigated the characteristics of the material-flow behavior during the formation and its effect on the microstructure of the extruded sheet metal using the finite element method (FEM. The actual parts and FEM simulation model were developed using a blank material made from AISI-1045 steel with a thickness of 5 mm; the material’s behavior was determined subject to the punch penetration depths of 20%, 40%, 60%, and 80% of the sheet thickness. The results indicated the formation and microstructure effects on the sheet metal extrusion parts and defects. Namely, when increasing penetration, narrowing the die orifice the material flows through, the material was formed by extruding, and defects were visibility, and the microstructure of the material’s grains’ size was flat and very fine. Extrusion defects were not found in the control material flow. The region of highly localized plastic deformation affected the material gain and mechanical properties. The FEM simulation results agreed with the experimental results. Moreover, FEM could be investigated as a tool to decrease the cost and time in trial and error procedures.

  19. Quantitative evaluation of apical extrusion of debris and irrigants using four rotary instrumentation systems: an in vitro study.

    Science.gov (United States)

    Nagaveni, S Aspalli; Balakoti, K Reddy; Smita, Karan; Ratnakar, P; Satish, S V; Aravind, T

    2013-11-01

    The apical extrusion of infected debris may have the potential to disrupt the balance between microbial aggression and host defense, resulting in incidents of acute inflammation. During preparation, irrigants and debris, such as bacteria, dentin filings and necrotic tissue may be extruded into the periradicular region leading to periapical inflammation and postoperative flare ups. Using an instrumentation technique that minimizes apical extrusion would be beneficial to both the practitioner and patient. The purpose of the study was to evaluate the weight of debris and volume of irrigant extruded apically from extracted teeth in vitro after endodontic instrumentation using four different rotary root canal instrumentation systems. Four groups of each 20 extracted mandibular premolars were instrumented using one of the four systems: ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland)), Hero-shaper (MicroMega, Besancon, France), RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) and K3 (SybronEndo, West Collins, CA). Debris and irrigant extruded from the apical foramen during instrumentation were collected in preweighed test tubes. Volume of irrigant extruded was noted. The containers were stored in incubator at 70° for two days to evaporate the moisture. Weight of dry debris was noted. Data was analyzed using Kruskall-Wallis and Mann-Whitney U test at a significance of 0.001. The results indicated that all of the instrumentation systems tested caused measurable apical extrusion of debris and irrigants. Higher extrusion was observed with Protaper system which was statistically significant with Hero-Shaper, RaCe and K3 systems. There were no statistical differences between Hero-shaper, K3 and RaCe systems (p irrigant. However, Hero-shaper, K3 and RaCe systems produced less extruded debris and irrigant than the Protaper system.

  20. Study on the extrusion mechanism of corn%玉米挤压膨化机理的研究

    Institute of Scientific and Technical Information of China (English)

    肖志刚; 张秀玲; 任运宏; 徐松滨

    2001-01-01

    本文以经过挤压膨化后的玉米为研究对象,在膨化倍数、碘蓝值、α-化度、还原能力等指标上进行对照试验,得出结论:玉米经过挤压膨化后,淀粉粒解体,糊精和还原糖增加,蛋白质变性,氨基酸和缩氨酸含量增加,脂肪减少,水溶性成分增加。从而为挤压膨化技术在玉米深加工领域中的应用提供了理论依据。%Corn after extrusion is studied.Expandable multiple,blue number of idodine,degree of α ,reduction ability are compared with the control.After extrusion,corn starch grain decomposed,dextrin and reducible carbohydrate increased,protein is denatured,content of amino acid and peptide improved,fat reduced and content of aqueous solution upgraded.This conclusion therefore provides a theoretical proof for the application of technology of extrusion in the field of further processing of corn.

  1. Study on expansion properties of extruded giseng by twin-screw extruder%人参粉挤压制品膨化特性的研究

    Institute of Scientific and Technical Information of China (English)

    李范洙; 金铁; 崔福顺; 吕龙石; 柳基亨

    2010-01-01

    探讨双螺杆挤压条件对人参挤压制品膨化品质的影响,以人参粉末为原料,利用双螺杆挤压机制备产品,分析不同物料含水量和机筒温度对制品的径向膨化率、水溶性指数、吸水性指数以及显微结构的影响.结果表明,人参挤压制品的径向膨化率在物料含水量30%、机筒温度100℃时最高(1.32),气孔细小而均匀.水溶性指数随物料含水量的增加而减少,随温度升高而增加,在20%、140℃时水溶性指数最高(44.77%).人参经双螺杆挤压不仅发生膨化,而且其制品质地疏松、均匀,有望开发膨化类人参保健休闲食品.

  2. 基于Matlab的双螺杆压缩机转子盘形铣刀数字化设计方法%Digitized Design Method to Disc Milling Cutter of Twin-screw Compressor's Rotor Based on Matlab

    Institute of Scientific and Technical Information of China (English)

    王小明; 罗芝华; 杨志; 徐家瑺; 王文贵

    2012-01-01

    In the design process of a twin-screw compressor's tool, solving equation is more complicated and time-consuming for practice application, due to involving nonlinear equation, such as implicit function and trigonometric functions, which directly affect the tool design precision and efficiency. The appropriate numerical solution methods for nonlinear equations were presented to realize digital design of milling cutter. Taking an improved SRM type line as an example, it was fast and accurately calculated by using Mat-lab, so a series of effective discrete points' data were gotten, to achieve the purpose of digitally showing the blade shape of tools, and to conveniently use AutoCAD or Pro/E to render tools. It is a precise and efficient way for designing milling tools to cut screw surface.%双螺杆压缩机螺杆成形铣刀设计计算过程中涉及到隐函数和三角函数等非线性方程,在现场实际应用中求解方程较为复杂而耗时,直接影响刀具设计的精度和效率.提出选取适当的数值求解方法来求解非线性方程已达到数字化设计铣刀的目的.以改进后的SRM型线为实例,应用Matlab进行快速准确的求解,得到一系列有效的离散点数据,以达到数字化表示刀具刃形的目的,方便采用AutoCAD或Pro/E绘制刀具结构图,是螺杆型面铣削刀具数字化设计的一种精确而快捷的方法.

  3. Scale up tools in reactive extrusion and compounding processes. Could 1D-computer modeling be helpful?

    Science.gov (United States)

    Pradel, J.-L.; David, C.; Quinebèche, S.; Blondel, P.

    2014-05-01

    Industrial scale-up (or scale down) in Compounding and Reactive Extrusion processes is one of the most critical R&D challenges. Indeed, most of High Performances Polymers are obtained within a reactive compounding involving chemistry: free radical grafting, in situ compatibilization, rheology control... but also side reactions: oxidation, branching, chain scission... As described by basic Arrhenius and kinetics laws, the competition between all chemical reactions depends on residence time distribution and temperature. Then, to ensure the best possible scale up methodology, we need tools to match thermal history of the formulation along the screws from a lab scale twin screw extruder to an industrial one. This paper proposes a comparison between standard scale-up laws and the use of Computer modeling Software such as Ludovic® applied and compared to experimental data. Scaling data from a compounding line to another one, applying general rules (for example at constant specific mechanical energy), shows differences between experimental and computed data, and error depends on the screw speed range. For more accurate prediction, 1D-Computer Modeling could be used to optimize the process conditions to ensure the best scale-up product, especially in temperature sensitive reactive extrusion processes. When the product temperature along the screws is the key, Ludovic® software could help to compute the temperature profile along the screws and extrapolate conditions, even screw profile, on industrial extruders.

  4. 香菇粉挤压膨化产品研发及其性质研究%Study of the Optimal Conditions and Characteristics of Mushroom Extrusion Product

    Institute of Scientific and Technical Information of China (English)

    徐兴阳; 梁文明; 邵卓; 徐慧; 陈野

    2016-01-01

    The aim of this research was to extrude mushroom using a twin screw extruder (SYSLG32-II, Jinan).The design of orthogonal experiment was through composite scores, then it was obtained the optimum conditions of mushroom extrusion. The results showed that the optimal conditions were as follows: barrel temperature 140 ℃, moisture content 20 %, mushroom content 25 %. Under these conditions , the product achieved the highest sensory scores 9.96. It was a light brown, shiny, delicate, crispy mushroom flavor snack. The research of sectional expansion indices of the product showed that when the conditions were mushroom content 20 %, moisture content 25 %, and barrel temperature 140 ℃, the maximum sectional expansion indices was 20.81,25.41,19.55, respectively. The crystallization temperature of extrusion products was lower than mushroom powder. The mushroom powder was loose flakes without rules while the extrusion products were regularly-shaped particles.%以香菇粉为原料,添加一定量的玉米淀粉,采用双螺杆挤压机挤压膨化生产营养健康的香菇膨化食品。以综合评分为指标设计正交试验,得出香菇粉挤压膨化最佳工艺条件为:香菇粉添加量25%,物料水分含量20%,挤压膨化温度140℃。在此条件下,香菇粉挤压膨化食品成浅褐色,有光泽,内部有均匀小孔洞,口感细腻,酥脆可口,有特殊的香菇风味,感官评分最高为9.96分。在针对产品截面膨化率的单因素试验中,结果表明香菇粉添加量为20%时,产品截面膨化率最大为20.81;物料水分含量为25%时产品最大截面膨化率为25.41,温度在140℃时出现最大截面膨化率19.55。热特性分析表明挤压后产品的结晶温度和焓变值均低于未挤压的香菇粉,经电镜观察香菇粉由挤压前的松散无规则片状变成挤压后的规则颗粒状。

  5. Influence of high moisture extrusion on property of textured soybean protein%高湿挤压对组织化大豆蛋白产品特性的影响

    Institute of Scientific and Technical Information of China (English)

    于国萍; 孙志欣

    2009-01-01

    Soybean protein isolate (SPI), wheat gluten (WG) and low-temperature defatted soybean (LTDS) as the main raw materials were used to produce high-moisture textured soybean protein (TSP) by SYSLG30-IV twin-screw extruder with cooling die. The effect of the three factors of extrusion processing (material moisture, barrel temperature, screw speed) on the nitrogen solubility index (NSI), the change of urease activity, protein digestibility in vitro, microstructure of extrudate were studied. The results showed that NSI of extrusion ranged from 6.5% -8.5 %; the urease activity of TSP reduced significantly; protein digestibility in vitro increased 12.1% and fully high moisture TSP was with dense structure and springiness, and had obvious texturized structure.%以大豆分离蛋白、谷朊粉、低温脱脂豆粕为主要原料,通过带冷却模具的SYSLG30-IV型双螺杆挤压实验机.生产高湿组织化大豆蛋白产品.探讨了挤压过程物料水分、机筒温度、螺杆转速3个因素对产品氮溶解指数的影响规律,同时研究了经过高湿挤压前后试验原料脲酶活性和体外消化率及微观结构的变化.结果表明.经高湿挤压后产品氮溶解指数一般在6.5%-8.5%之间;大豆蛋白脲酶活性大大降低;蛋白质的体外消化率提高12.1%;充分组织化的大豆蛋白结构致密,有弹性,具有明显的组织化结构.

  6. Etching Behavior of Aluminum Alloy Extrusions

    Science.gov (United States)

    Zhu, Hanliang

    2014-11-01

    The etching treatment is an important process step in influencing the surface quality of anodized aluminum alloy extrusions. The aim of etching is to produce a homogeneously matte surface. However, in the etching process, further surface imperfections can be generated on the extrusion surface due to uneven materials loss from different microstructural components. These surface imperfections formed prior to anodizing can significantly influence the surface quality of the final anodized extrusion products. In this article, various factors that influence the materials loss during alkaline etching of aluminum alloy extrusions are investigated. The influencing variables considered include etching process parameters, Fe-rich particles, Mg-Si precipitates, and extrusion profiles. This study provides a basis for improving the surface quality in industrial extrusion products by optimizing various process parameters.

  7. Preparation of poly(L-lactic acid) by using twin-screw extruder as a reactor%双螺杆反应挤出法开环聚合制备聚乳酸的研究

    Institute of Scientific and Technical Information of China (English)

    李杨; 刘鹏; 吴剑波; 杨革生; 邵惠丽; 胡学超

    2014-01-01

    Direct preparation of poly(L-lactic acid) (PLLA) by ring-opening polymerization of L-lactide using twin-screw extruder was carried out .The influence of the catalyst type and content , the polymerization temperature and the polymerization time on polymer properties were investigated .The results showed that the relative appropri-ate reaction conditions were as follows:2-ethylhexanoic acid tin ( II) salt was selected as the main catalyst and 1,do-decanol was selected as the cocatalyst , the polymerization temperature was 170℃, the molar ratio of monomer/cat-alyst was 3 000∶1 and the polymerization time was 120 min.Under the above conditions , the PLLA polymer with a molecular weight of about 5.3 ×104 could be obtained.The structure and thermal properties of polymer were char-acterized by FT-IR, 1 H-NMR, DSC and TG, etc.%以双螺杆挤出机为反应器来实施L-丙交酯的开环聚合制备聚乳酸,探讨了催化剂种类及其含量、聚合温度及聚合时间等因素对聚合产物性质的影响。实验获得的相对适宜的工艺条件如下:优选辛酸亚锡(Sn(Oct)2)/1-十二醇(CH3(CH2)11OH)为复合催化剂体系,单体与催化剂摩尔比为3000∶1,聚合温度为170℃,聚合时间为120 min,由此可获得粘均相对分子质量为5.3×104的聚(L-乳酸)。在此基础上,进一步采用 FT-IR、1H-NMR、DSC和 TG等分析手段对聚合产物的结构和热性能进行了表征。

  8. THE STUDY OF PATTERNS OF PRE-EXTRUSION PREPARATION OIL CULTURES TO THE PRESSING PROCESS

    Directory of Open Access Journals (Sweden)

    L. N. Frolova

    2015-01-01

    Full Text Available One of the most promising oil crops in the Russian Federation is saffron. Camelina seeds contain from 26 to 46% oil, which is different from other oils rich in cruciferous gondoinic, linolenic and linoleic acids, and relatively low erucic acid, has a high content of the biologically active substances (sterols, carotenes and carotenoids, chlorophylls and tocopherols. The main task in the processing of oilseeds is the maximum extraction of oil with a high quality of the products obtained: unrefined oil, cake and meal. In conventional technology of oil, the raw material is subjected to repeated heating significantly. Proposed the following processing flow chart: camelina seeds were subjected to moisture-heat treatment beforehand in an extruder, and then hot-pressed to a screw press a single action, so that the oil content of the cake after pressing was 17-19%. When using an extrusion process is suppressed anti-nutritional properties contained in the seeds of camelina. Found that the oil obtained after the preliminary preparation of the extrusion as compared with the oil produced by traditional technology, comprises more tocopherols, phospholipids less chlorophyll, free fatty acids and peroxides. Thus, it has a longer shelf life, has good fluidity, easily refined.

  9. An in vitro study of composites of poly(L-lactide-co-ε-caprolactone), β-tricalcium phosphate and ciprofloxacin intended for local treatment of osteomyelitis

    Science.gov (United States)

    Ahola, Niina; Männistö, Noora; Veiranto, Minna; Karp, Matti; Rich, Jaana; Efimov, Alexander; Seppälä, Jukka; Kellomäki, Minna

    2013-01-01

    Osteomyelitis is a bacterial disease that can become chronic, and treatment often includes a surgical operation to remove infected bone. The aim of this study was to develop and investigate in vitro bone filling composite materials that release ciprofloxacin to kill any remaining bacteria and contain bioceramic to help the bone to heal. Three composites of poly(L-lactide-co-ε-caprolactone), β-tricalcium phosphate and ciprofloxacin were compounded using twin-screw extrusion and sterilized by gamma irradiation. Drug release and degradation of the composites were investigated in vitro for 52 weeks. The composite with 50 wt% of β-TCP had the most promising ciprofloxacin release profile. The ceramic component accelerated the drug release that occurred in three phases obeying first-order kinetics. Inhibition zone testing using bioluminescence showed that the released ciprofloxacin had effect in eradicating a common osteomyelitis causing bacteria Pseudomonas aeruginosa. During the in vitro degradation test series, molar weight of the polymer matrix of the composites decreased rapidly. Additionally, 1H-NMR analysis showed that the polymer had blocky structure and the comonomer ratio changed during hydrolysis. The tested composites showed great potential to be developed into bone filler materials for the treatment of osteomyelitis or other bone related infections. PMID:23507926

  10. Development of a process map: A step towards a regime map for steady-state high shear wet twin screw granulation

    DEFF Research Database (Denmark)

    Kumar, Ashish; Dhondt, Jens; Vercruysse, Jurgen

    2016-01-01

    involves the combination of screw speed, material throughput and torque required to rotate the screws was correlated with the applied liquid-to-solid ratio to present process maps. The study suggested that, despite an increase in the granule size by the increasing liquid-to-solid ratio, most of the liquid...... contributes to formation of oversized granules. Therefore, keeping the liquid-to-solid ratio in a lower range and increasing the energy input to the system can be effectively used to lower the mean granule size. Changes in the screw geometry should also be explored to improve solid liquid mixing and breakage...... dimensionless groups that control granule attributes, with the ultimate aim of producing a generalised regime map. (C) 2015 Elsevier B.V. All rights reserved....

  11. Evaluation of dispersive mixing, extension rate and bubble size distribution using numerical simulation of a non-Newtonian fluid in a twin-screw mixer

    Science.gov (United States)

    Rathod, Maureen L.

    Initially 3D FEM simulation of a simplified mixer was used to examine the effect of mixer configuration and operating conditions on dispersive mixing of a non-Newtonian fluid. Horizontal and vertical velocity magnitudes increased with increasing mixer speed, while maximum axial velocity and shear rate were greater with staggered paddles. In contrast, parallel paddles produced an area of efficient dispersive mixing between the center of the paddle and the barrel wall. This study was expanded to encompass the complete nine-paddle mixing section using power-law and Bird-Carreau fluid models. In the center of the mixer, simple shear flow was seen, corresponding with high [special character omitted]. Efficient dispersive mixing appeared near the barrel wall at all flow rates and near the barrel center with parallel paddles. Areas of backflow, improving fluid retention time, occurred with staggered paddles. The Bird-Carreau fluid showed greater influence of paddle motion under the same operating conditions due to the inelastic nature of the fluid. Shear-thinning behavior also resulted in greater maximum shear rate as shearing became easier with decreasing fluid viscosity. Shear rate distributions are frequently calculated, but extension rate calculations have not been made in a complex geometry since Debbaut and Crochet (1988) defined extension rate as the ratio of the third to the second invariant of the strain rate tensor. Extension rate was assumed to be negligible in most studies, but here extension rate is shown to be significant. It is possible to calculate maximum stable bubble diameter from capillary number if shear and extension rates in a flow field are known. Extension rate distributions were calculated for Newtonian and non-Newtonian fluids. High extension and shear rates were found in the intermeshing region. Extension is the major influence on critical capillary number and maximum stable bubble diameter, but when extension rate values are low shear rate has

  12. Mixing Study of Poly( lactic acid ) /Cellulose Acetate Propionate Composites%聚乳酸/乙酸丙酸纤维素复合材料共混研究

    Institute of Scientific and Technical Information of China (English)

    张明明; 程增会; 金立维

    2012-01-01

    采用双螺杆挤出工艺制备聚乳酸( PLA)/乙酸丙酸纤维素(CAP)简单共混复合材料.通过力学性能、吸水性、扫描电子显微镜、动态热机械分析和热重分析等手段,研究了CAP用量对复合材料拉伸强度、微观形态及松弛行为的影响.结果表明,随着CAP用量的增加,其拉伸强度出现峰值,加入CAP使复合材料具有较好的力学性能,同时没有影响PLA的链段运动.%The binary mixing composites of poly ( 1 actic acid) ( PLA ) / cellulose acetate propionate ( CAP ) were prepared by twin-screw extrusion process. The effects of CAP content on tensile strength, morphology and relaxation behavior of the composites were studied by mechanical property test, water absorption, SEM, DMA and TG analysis. The research showed that with increase of CAP content, a peak occured during the curve of tensile strength. The composites had better mechanical properties with adding CAP. Meanwhile, the CAP molecules did not affect the relaxation activity of PLA chains.

  13. Comparison of apical sealing and periapical extrusion of the ThermaFil obturation technique with and without MTA as an apical barrier: An in vitro study

    Directory of Open Access Journals (Sweden)

    Satish Kumar

    2011-01-01

    Full Text Available Aim: The aim of the study was to compare the conventional ThermaFil obturation technique and ThermaFil obturation with mineral trioxide aggregate (MTA as an apical barrier, with regard to apical sealing and extrusion. Materials and Methods: Twenty extracted human canines were instrumented using a crown-down technique and divided into two groups. The experimental group was obturated using ThermaFil obturation with MTA as an apical barrier and the control group was obturated using the conventional ThermaFil obturation technique. AH Plus sealer was used in both the groups. Apical extrusion was recorded. Teeth of both the groups were coated with nail polish, except for the apical 3 mm. After 24 h, they were suspended in black India ink for 48 h. Canines were decalcified, rendered transparent, and linear dye penetration was measured under ×40 stereomicroscope. Results: There was a significant extrusion noticed in conventional ThermaFil obturation technique. Frequency of extrusion of sealer and/or gutta-percha was supposed to be evaluated using χ² test, but since the values of the samples of ThermaFil plus MTA group were zero, statistical analysis could not be conducted, whereas linear dye leakage was calculated with Mann-Whitney U test because the distribution was abnormal. Conclusion: Although ThermaFil plus MTA group showed microleakage, extrusion of sealer and the core material was prevented in comparison with conventional ThermaFil obturation technique. It is advantageous to use MTA as an apical plug as there is no fear of apical extrusion and the root canal system can then be packed three dimensionally against this barrier using any thermoplasticized gutta-percha obturation technique.

  14. Elaboration de membranes pour piles a combustible par extrusion

    OpenAIRE

    Chabert, France

    2004-01-01

    The aim of these studies was to process membranes by extrusion to be used in fuel cells. The functional polymers used are generally processed by polluting techniques like casting-evaporation, which are not easily transposable on industrial scale. Extrusion is a widely used shaping operation in the polymer processing industry. However, extrusion had not been used until now for arylsulfonic ionic polymers. In order to avoid any risk of degradation of the polymer during extrusion, it was necessa...

  15. KINETICS STUDY ON MELT GRAFTING ACRYLIC ACID ONTO LLDPE USING REACTIVE EXTRUSION

    Institute of Scientific and Technical Information of China (English)

    Qiang Shi; Lian-chao Zhu; Chuan-lun Cai; Jing-hua Yin

    2005-01-01

    The kinetics of melt grafting acrylic acid (AA) onto linear low density polyethylene (LLDPE) by using reactive extrusion was investigated. The polymeric peroxides (POOP and POOH) generated by electron beam irradiation were used to initiate the graft reaction. The samples taken out from the barrel at five ports along screw axis were analyzed by FTIR. The spectra show that both the graft copolymerization and homopolymerization proceed in two stages: the graft degree (or mass of homopolymer) increases linearly with the reaction time in the initial stage, and then gradually in the second stage. The rate of graft copolymerization Rg is always faster than that of homopolymerization Rh in the present system and the activation interpreted in terms of solubility and diffusion of monomer, as well as the reactivity and the concentration of reactive species.The relationships between reaction rate and monomer concentration and peroxide concentration were found to be. Rg ∝ [M]1.46[POOP+POOH]0.53 and Rh ∝ [M]1.08[POOH]0.51, which indicate that the addition of monomer to polymeric radicals is a slow step for the graft copolymerization.

  16. Local mixing effects of screw elements during extrusion

    NARCIS (Netherlands)

    Einde, van den R.M.; Kroon, P.J.; Goot, van der A.J.; Boom, R.M.

    2005-01-01

    An in-line method was applied to determine local residence time distribution (RTD) at two places in a completely filled corotating twin screw extruder. Axial mixing effects of different types of elements were evaluated. Paddles +90 degrees induced flow patterns that appear to be circular, both

  17. Rational development of solid dispersions via hot-melt extrusion using screening, material characterization, and numeric simulation tools.

    Science.gov (United States)

    Zecevic, Damir E; Wagner, Karl G

    2013-07-01

    Effective and predictive small-scale selection tools are inevitable during the development of a solubility enhanced drug product. For hot-melt extrusion, this selection process can start with a microscale performance evaluation on a hot-stage microscope (HSM). A batch size of 400 mg can provide sufficient materials to assess the drug product attributes such as solid-state properties, solubility enhancement, and physical stability as well as process related attributes such as processing temperature in a twin-screw extruder (TSE). Prototype formulations will then be fed into a 5 mm TSE (~1-2 g) to confirm performance from the HSM under additional shear stress. Small stress stability testing might be performed with these samples or a larger batch (20-40 g) made by 9 or 12 mm TSE. Simultaneously, numeric process simulations are performed using process data as well as rheological and thermal properties of the formulations. Further scale up work to 16 and 18 mm TSE confirmed and refined the simulation model. Thus, at the end of the laboratory-scale development, not only the clinical trial supply could be manufactured, but also one can form a sound risk assessment to support further scale up even without decades of process experience.

  18. Direct preparation of poly(L-lactic acid) by ring-opening polymerization of L-lactide using a twin-screw extruder%双螺杆法丙交酯直接反应挤出制备聚乳酸

    Institute of Scientific and Technical Information of China (English)

    吴剑波; 刘鹏; 李杨; 杨革生; 邵惠丽

    2012-01-01

    The poly(L-lactic acid) (PLLA) was rapidly synthesized from L-lactide (L-LA) by using 2-ethylhexanoic acid tin (Ⅱ) salt and triphenylphosphine as the catalyst system and using a twin-screw ex-truder as a reactor. The effects of the polymerization time, polymerization temperature, the screw speed and the catalyst content on polymer properties were investigated. The results showed that when the twin-screw speed was 110 r/min,the polymerization temperature was 170℃ ,the molar ratio of monomer/catalyst was 2 000 : 1 and the polymerization time was 1. 5 h, the PLLA polymer with a molecular weight of about 49 000 and optical purity of 93% could be obtained.%以L-丙交酯为原料,辛酸亚锡和三苯基膦为催化体系,利用双螺杆挤出机快速制备具有一定分子量的聚乳酸.研究了聚合时间、聚合温度、螺杆转速以及催化剂含量对聚合产物性质的影响.结果表明,在双螺杆转速110 r/min,聚合温度170℃,单体与催化剂摩尔比为2000:1条件下,聚合1.5h,能获得粘均分子量约为4.9万、光学纯度达到93%的聚乳酸.

  19. Hot extrusion of Be–Ti powder

    Energy Technology Data Exchange (ETDEWEB)

    Kurinskiy, P., E-mail: petr.kurinskiy@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials—Applied Materials Physics (IAM—AWP), PO Box 3640, 76021 Karlsruhe (Germany); Leiste, H. [Karlsruhe Institute of Technology, Institute for Applied Materials—Applied Materials Physics (IAM—AWP), PO Box 3640, 76021 Karlsruhe (Germany); Goraieb, A.A. [Karlsruhe Beryllium Handling Facility (KBHF GmbH), Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Mueller, S. [Extrusion Research and Development Center, TU Berlin, Sekr. TIB 4/1-2, Gustav-Meyer-Allee 25, 13355 Berlin (Germany)

    2015-10-15

    Highlights: • Extrusion in double-walled containment of Be–Ti blended powder was investigated. • Fabrication of Be–Ti rods by extrusion at 700 °C showed more satisfactory results compared to an extrusion at 900 °C. • Factors which influence homogeneous and stable metal flow during extrusion are discussed. - Abstract: Be–30.8 wt.%Ti powder mixture was extruded in copper and steel containers at 700 and 900 °C, respectively. In both cases, achieved extrusion ratio was 7:1. Investigations of microstructure of manufactured Be–Ti rods revealed that processing temperature has a great influence on the metal flow during the extrusion as well as formation of beryllide phases. The results obtained by X-ray diffraction (XRD) analysis proved that brittle intermetallic phases were formed by processing at 900 °C; while no evidence of reaction between beryllium and titanium was detected after extrusion at 700 °C. Additionally, high-temperature annealing tests of produced Be–Ti samples were performed in order to study the evolution of the phase composition after the heat treatment. The effects of different mechanical properties of core materials (beryllium and titanium) and containers on uniform deformation are discussed in this work.

  20. A finite element model of ultrasonic extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, M [Department of Mechanical Engineering, University of Glasgow, G12 8QQ (United Kingdom); Daud, Y, E-mail: m.lucas@mech.gla.ac.u [College of Science and Technology, UTM City Campus, Kuala Lumpur (Malaysia)

    2009-08-01

    Since the 1950's researchers have carried out investigations into the effects of applying ultrasonic excitation to metals undergoing elastic and plastic deformation. Experiments have been conducted where ultrasonic excitation is superimposed in complex metalworking operations such as wire drawing and extrusion, to identify the benefits of ultrasonic vibrations. This study presents a finite element analysis of ultrasonic excitation applied to the extrusion of a cylindrical aluminium bar. The effects of friction on the extrusion load are reported for the two excitation configurations of radially and axially applied ultrasonic vibrations and the results are compared with experimental data reported in the literature.

  1. A finite element model of ultrasonic extrusion

    Science.gov (United States)

    Lucas, M.; Daud, Y.

    2009-08-01

    Since the 1950's researchers have carried out investigations into the effects of applying ultrasonic excitation to metals undergoing elastic and plastic deformation. Experiments have been conducted where ultrasonic excitation is superimposed in complex metalworking operations such as wire drawing and extrusion, to identify the benefits of ultrasonic vibrations. This study presents a finite element analysis of ultrasonic excitation applied to the extrusion of a cylindrical aluminium bar. The effects of friction on the extrusion load are reported for the two excitation configurations of radially and axially applied ultrasonic vibrations and the results are compared with experimental data reported in the literature.

  2. La technologie d’extrusion bi-vis, une solution originale et performante pour le bioraffinage du tournesol plante entière

    Directory of Open Access Journals (Sweden)

    Evon Philippe

    2010-11-01

    Full Text Available The objective of this study is to evaluate the feasibility of an aqueous process for the biorefinery of sunflower whole plant using a co-rotating twin-screw extruder. Traditionally, aqueous extraction of oil is looked upon as an environmentally cleaner alternative technology to the solvent extraction (Rosenthal et al., 1996 and the twin-screw extruder carries out three essential unit operations continuously: conditioning and grinding of whole plant, liquid/solid extraction and liquid/solid separation. Wringing out the mixing is favoured thanks to the stalk fibers. However, drying of the cake meal is not optimal and lixiviation of cotyledon cells within the seed is incomplete. Extraction efficiency depends on the operating conditions: screw rotation speed, input flow rates of whole plant and water. In best conditions, oil yield is 57% and residual oil content in the cake meal is 14%. These conditions lead to the co-extraction of proteins, pectins and hemicelluloses. Protein yield is 44% and residual protein content in the cake meal is 7%. Oil is extracted in the form of two oil-in-water emulsions stabilized by phospholipids and proteins at interface. An aqueous extract containing part of the water-soluble constituents from whole plant, mainly proteins and pectins, is also generated. As a mixture of fibers and proteins, the cake meal can be moulded by thermo-pressing. Panels have promising mechanical properties in bending.

  3. Evaluation of Extrusion Technique for Nanosizing Liposomes

    Directory of Open Access Journals (Sweden)

    Sandy Gim Ming Ong

    2016-12-01

    Full Text Available The aim of the present study was to study the efficiency of different techniques used for nanosizing liposomes. Further, the aim was also to evaluate the effect of process parameters of extrusion techniques used for nanosizing liposomes on the size and size distribution of the resultant liposomes. To compare the efficiency of different nanosizing techniques, the following techniques were used to nanosize the liposomes: extrusion, ultrasonication, freeze-thaw sonication (FTS, sonication and homogenization. The extrusion technique was found to be the most efficient, followed by FTS, ultrasonication, sonication and homogenization. The extruder used in the present study was fabricated using readily available and relatively inexpensive apparatus. Process parameters were varied in extrusion technique to study their effect on the size and size distribution of extruded liposomes. The results obtained indicated that increase in the flow rate of the extrusion process decreased the size of extruded liposomes however the size homogeneity was negatively impacted. Furthermore, the liposome size and distribution was found to decline with decreasing membrane pore size. It was found that by extruding through a filter with a pore size of 0.2 µm and above, the liposomes produced were smaller than the pore size, whereas, when they were extruded through a filter with a pore size of less than 0.2 µm the resultant liposomes were slightly bigger than the nominal pore size. Besides that, increment of extrusion temperature above transition temperature of the pro-liposome had no effect on the size and size distribution of the extruded liposomes. In conclusion, the extrusion technique was reproducible and effective among all the methods evaluated. Furthermore, processing parameters used in extrusion technique would affect the size and size distribution of liposomes. Therefore, the process parameters need to be optimized to obtain a desirable size range and homogeneity

  4. Comparison between decrosslinking of crosslinked high and low density polyethylenes via ultrasonically aided extrusion

    Science.gov (United States)

    Isayev, Avraam I.; Huang, Keyuan

    2016-03-01

    Among various crosslinked plastics, recycling of crosslinked polyethylenes is of a great importance due to the presence of a three-dimensional network. To solve this problem, novel environmentally friendly technologies for decrosslinking of the crosslinked polymers are developed based on ultrasonically assisted single (SSE) and twin screw (TSE) extruders. In particular, decrosslinking of peroxide crosslinked high-density polyethylene (XHDPE) and low-density polyethylene (XLDPE) by means of an ultrasonic SSE and TSE is investigated. Barrel pressure, die pressure and ultrasonic power consumption during extrusion are recorded. Swelling, rheological, thermal analysis and tensile tests are used to elucidate the structure-property relationships of decrosslinked XHDPE and XLDPE. The frequency dependencies of the storage and loss moduli, complex viscosity and tangent loss of XHDPE, XLDPE and their decrosslinked networks are described by the post critical gel model with its parameters correlated with gel fraction and crosslink density. The dynamic, thermal and tensile properties of the decrosslinked XHDPE and XLDPE are greatly affected by the type of preferential bond breakage. It was found that the decrosslinking of XLDPE is more difficult than that of XHDPE. An analysis based on the Horikx function reveals a highly preferential breakage of crosslinks during decrosslinking of XHDPE. In contrast to decrosslinking of XHDPE, the presence of long-chain branching in XLDPE is found to lead to the breakage of its main chains during decrosslinking. An improvement and a reduction in mechanical properties of decrosslinked XHDPE and XLDPE are, respectively, observed in comparison with those of virgin XHDPE and XLDPE.

  5. Sistema portátil para medida on-line da distribuição de tempo de residência na extrusão Portable system for on-line measurement of the residence time distribution in twin-screw extrusion

    Directory of Open Access Journals (Sweden)

    Denilson M. Santos

    1999-06-01

    Full Text Available A Curva de Distribuição de Tempos de Residência - CDTR tem sido largamente usada para caracterização do tipo de fluxo em extrusoras, sendo que medidas "on-line" permitem diagnosticar de modo muito rápido problemas como desgaste entre a rosca e o barril da extrusora, estagnação do material e outros. A CDTR pode ser determinada fazendo-se uso da técnica de estímulo de pulso único, onde um traçador é introduzido no sistema em um dado instante e sua concentração é estimada na saída. Este artigo propõe um sistema portátil de medida "on-line" feito através da variação da luz transmitida medida com um detector constituído por uma fonte de radiação visível e uma célula fotoelétrica e um software de coleta e tratamento de dados. Usando-se este sistema em uma extrusora de dupla rosca co-rotacional interpenetrante, pode-se verificar que a CDTR é muito mais sensível à variações na taxa de alimentação do que da velocidade de rotação da rosca e que as frações mais lentas do traçador podem demorar quatro vezes mais que as mais rápidas para saírem. Aumento na velocidade de rotação da rosca e/ou redução na taxa de alimentação aumenta o fluxo axial alargando a CDTR.The residence time distribution curve (RTDC is largely used to characterize extruder and continuous mixers flow types and on-line measurements allow quick diagnosis of their related problems. The RTDC can be obtained by the single impulse technique, where the tracer is fed into the system at one time and its concentration is estimated at the exit. This paper presents a portable on-line system consisting of a detector which has a light source, an photoelectric cell and a software to collect and analyze the data. Using this system in an intermeshing co-rotating double screw extruder one can verify that the RTDC is much more sensitive to changes of the feeding rate than the screw speed and that the slower tracer fractions may take four times longer than the faster ones to get out. Increase in screw speed and/or reduction in feeding rate increases the axial flow, widening the RTDC.

  6. Apical extrusion of debris and irrigants using hand and three rotary instrumentation systems- An in vitro study

    Directory of Open Access Journals (Sweden)

    Koppolu Madhusudhana

    2010-01-01

    Full Text Available Introduction: Sterilization of the root canal is a prime aim of successful endodontics. The cleaning and shaping of the canal is directed as achieving this goal. The extrusion of apical debris has a deleterious effect on the prognosis of root canal treatment. Several instrument designs and instrumentation techniques have been developed to prevent this. Materials and Methods: Forty caries free single rooted human mandibular premolar teeth were divided in four groups of ten teeth each. Teeth in each group were instrumented until the working length with rotary ProTaper, K3, Mtwo systems, and hand K-type stainless steel files. Debris and irrigant extruded from the apical foramen were collected into vials and the amounts were quantitatively determined. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests. Results: The results show that all instrumentation techniques produced significant amount of extruded debris and irrigant. The engine-driven nickel-titanium systems showed less apical extrusion of debris and irrigant than manual technique. No statistically significant difference was found between the groups at [P > 0.05]. Maximum apical debris and irrigant extrusion was seen with K-file group and least in the Mtwo group. Conclusions: The use of rotary files and techniques to perform instrumentation does show less extrusion of the debris and irrigant from the apex. This can contribute to more successful endodontic therapy.

  7. Quantitative evaluation of apical extrusion of intracanal bacteria using K3, Mtwo, RaCe and protaper rotary systems: An in vitro study

    Science.gov (United States)

    Garlapati, Roopadevi; Venigalla, Bhuvan Shome; Patil, Jayaprakash D; Raju, RVSC; Rammohan, Chintamani

    2013-01-01

    Aim: This aim of this study was to evaluate the number of bacteria extruded apically during root canal preparation using Four Rotary instrumentation techniques. Materials and Methods: A total of 50 extracted mandibular premolars were selected, access cavities prepared and inserted in to rubber stoppers of 10 mL glass vial. Root canals were contaminated with a suspension of Enterococcus faecalis (E. faecalis) American Type Culture Collection (ATCC) 29212 and incubated for 24 h at 37°C. Debris extruded from the apical foramen during instrumentation was collected into vials. The numbers of Colony-forming units were determined for each sample. Statistical Analysis: The data obtained were analyzed using the one-way ANOVA followed by post-hoc tukey's test with a P = 0.05 as the level for statistical significance. Results: Results suggested a statistically significant difference in the number of colony forming units between four experimental rotary Nickel-Titanium instrumentation groups (P < 0.001). Conclusion: Although, extrusion of bacteria was found in all the experimental groups. There was less bacterial extrusion in K3 Group while more bacterial extrusion was seen in Mtwo Group. PMID:23956529

  8. The influence of drug physical state on the dissolution enhancement of solid dispersions prepared via hot-melt extrusion: a case study using olanzapine.

    Science.gov (United States)

    Pina, Maria Fátima; Zhao, Min; Pinto, João F; Sousa, João J; Craig, Duncan Q M

    2014-04-01

    In this study, we examine the relationship between the physical structure and dissolution behavior of olanzapine (OLZ) prepared via hot-melt extrusion in three polymers [polyvinylpyrrolidone (PVP) K30, polyvinylpyrrolidone-co-vinyl acetate (PVPVA) 6:4, and Soluplus® (SLP)]. In particular, we examine whether full amorphicity is necessary to achieve a favorable dissolution profile. Drug–polymer miscibility was estimated using melting point depression and Hansen solubility parameters. Solid dispersions were characterized using differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy. All the polymers were found to be miscible with OLZ in a decreasing order of PVP>PVPVA>SLP. At a lower extrusion temperature (160°C), PVP generated fully amorphous dispersions with OLZ, whereas the formulations with PVPVA and SLP contained 14%-16% crystalline OLZ. Increasing the extrusion temperature to 180°C allowed the preparation of fully amorphous systems with PVPVA and SLP. Despite these differences, the dissolution rates of these preparations were comparable, with PVP showing a lower release rate despite being fully amorphous. These findings suggested that, at least in the particular case of OLZ, the absence of crystalline material may not be critical to the dissolution performance. We suggest alternative key factors determining dissolution, particularly the dissolution behavior of the polymers themselves.

  9. Rat Palatability Study for Taste Assessment of Caffeine Citrate Formulation Prepared via Hot-Melt Extrusion Technology.

    Science.gov (United States)

    Tiwari, Roshan V; Polk, Ashley N; Patil, Hemlata; Ye, Xingyou; Pimparade, Manjeet B; Repka, Michael A

    2017-02-01

    Developing a pediatric oral formulation with an age-appropriate dosage form and taste masking of naturally bitter active pharmaceutical ingredients (APIs) are key challenges for formulation scientists. Several techniques are used for taste masking of bitter APIs to improve formulation palatability; however, not all the techniques are applicable to pediatric dosage forms because of the limitations on the kind and concentration of the excipients that can be used. Hot-melt extrusion (HME) technology is used successfully for taste masking of bitter APIs and overcomes some of the limitations of the existing taste-masking techniques. Likewise, analytical taste assessment is an important quality control parameter evaluated by several in vivo and in vitro methods, such as the human taste panel, electrophysiological methods, electronic sensor, and animal preference tests to aid in selecting a taste-masked formulation. However, the most appropriate in vivo method to assess the taste-masking efficacy of pediatric formulations remains unknown because it is not known to what extent the human taste panel/electronic tongue can predict the palatability in the pediatric patients. The purpose of this study was to develop taste-masked caffeine citrate extrudates via HME and to demonstrate the wide applicability of a single bottle-test rat model to record and compare the volume consumed of the taste-masked solutions to that of the pure API. Thus, this rat model can be considered as a low-cost alternative taste-assessment method to the most commonly used expensive human taste panel/electronic tongue method for pediatric formulations.

  10. Effect of Extrusion on the Mechanical and Rheological Properties of a Reinforced Poly(Lactic Acid: Reprocessing and Recycling of Biobased Materials

    Directory of Open Access Journals (Sweden)

    Víctor Peinado

    2015-10-01

    Full Text Available The aim of this research paper is to study the behaviour of a common used biopolymer (Poly(Lactic Acid (PLA after several reprocesses and how two different types of additives (a melt strength enhancer and a nanoadditive affect its mechanical and rheological properties. Systematic extraction of extrudate samples from a twin-screw compounder was done in order to study the effect in the properties of the reprocessed material. Detailed rheological tests on a capillary rheometer as well as mechanical studies on a universal tensile machine after preparation of injected specimens were carried out. Results evidenced that PLA and reinforced PLA materials can be reprocessed and recycled without a remarkable loss in their mechanical properties. Several processing restrictions and specific phenomena were identified and are explained in the present manuscript.

  11. 双螺杆压缩机及膨胀机在高温热泵与能量回收系统中的应用%Applications of Twin Screw Compressor and Expander in High-temperature Heat Pumps and Energy Recovery Systems

    Institute of Scientific and Technical Information of China (English)

    赵兆瑞; 唐昊; 沈九兵; 邢子文

    2014-01-01

    The demanding of energy conservation, emissions reduction and energy efficiency improvement becomes greater and greater nowadays, so that further investigations and applications on high-temperature heat pumps and energy recovery system are being widely conducted. The high-temperature heat pump mainly includes two kinds of system:heat pumps using R245fa as working medium and those adopting water as working fluid. The energy recovery systems also have two forms of application, i.e., organic rankine cycle (ORC) and water vapor expanding system. In such systems, twin screw compressors and expanders act as key parts, which influences the performance significantly. The application of twin screw compressors and expanders in these systems was introduced, and the research progress and application cases were presented.%随着节能减排、提高能效的需求增大,高温热泵和能量回收系统的研究及应用日益广泛。高温热泵主要有两种类型,一种是使用R245fa等高温工质的高温热泵,另一种是采用水蒸汽介质的高温热泵;能量回收系统也有两种形式,即有机工质郎肯循环(ORC)余热回收以及采用水蒸汽膨胀的回收系统。双螺杆压缩机及膨胀机作为此类系统的核心部件,对系统的性能有着重要的影响。本文介绍了双螺杆压缩机及膨胀机在这类系统中的应用情况,并给出了一些研究进展和应用案例。

  12. Corelation between Machines Assisted Endodontic Irrigant Agitation and Apical Extrusion of Debris and Irrigant: A Laboratory Study

    Directory of Open Access Journals (Sweden)

    Jatin Gupta

    2014-01-01

    Full Text Available Aims. To compare amount of root canal debris and irrigant extruded apically after irrigants agitation using closed and open chambers. Methods and Material. Sixty maxillary central incisors were selected, decoronated, and mounted in preweighed glass vials filled with distilled water. Biomechanical preparation was completed using ProTaper rotary files until number F4 and 1 mL of 3% NaOCl solution after each file use. Samples were randomly divided into closed or open chamber sets which were further subdivided into 6 groups, based on the agitation techniques: no agitation (control, canalBrush, lentulospiral, passive ultrasonic agitation (PUA, EndoActivator, and EndoVac. Canals were irrigated with 1 mL of 17% EDTA and agitated for 30 s and then flushed with 2 mL of distilled water. Apically extruded irrigant was measured and vials were kept in incubator for 5 days at 68°C for drying for weight calculation. Statistical Analysis. Analysis was done using Student’s t-test, one-way ANOVA, and post-hoc. Results. All agitation techniques showed apical extrusion of the debris and irrigant. The closed chamber apparatus showed significantly less extrusion of debris and irrigant than open chamber (P<0.05. Conclusions. EndoVac was found to be the safest agitation system among all test groups with regard to apical extrusion of debris and irrigant.

  13. Conservation of extrusion as an exit mechanism for Chlamydia.

    Science.gov (United States)

    Zuck, Meghan; Sherrid, Ashley; Suchland, Robert; Ellis, Tisha; Hybiske, Kevin

    2016-10-01

    Chlamydiae exit via membrane-encased extrusion or through lysis of the host cell. Extrusions are novel, pathogen-containing structures that confer infectious advantages to Chlamydia, and are hypothesized to promote cell-to-cell spread, dissemination to distant tissues and facilitate immune evasion. The extrusion phenomenon has been characterized for several Chlamydia trachomatis serovars, but a thorough investigation of extrusion for additional clinically relevant C. trachomatis strains and Chlamydia species has yet to be performed. The key parameters investigated in this study were: (i) the conservation of extrusion across the Chlamydia genus, (ii) the functional requirement for candidate Chlamydia genes in extrusion formation i.e. IncA and CT228 and (iii) extrusion-mediated uptake, and consequent survival of Chlamydia inside macrophages. Inclusion morphology was characterized by live fluorescence microscopy, using an inverted GFP strategy, at early and mid-stages of infection. Enriched extrusions were used to infect bone marrow-derived macrophages, and bacterial viability was measured following macrophage engulfment. Our results demonstrate that extrusion is highly conserved across chlamydiae, including ocular, STD and LGV biovars and divergent Chlamydia species. Consequently, this exit mechanism for Chlamydia may fulfill common advantages important for pathogenesis.

  14. Extrusão dos implantes em portadores de cavidade anoftálmica Anophthalmic cavity and implant extrusion

    Directory of Open Access Journals (Sweden)

    Silvana Artioli Schellini

    2007-10-01

    Full Text Available OBJETIVO: Avaliar as características dos portadores de cavidades anoftálmicas que desenvolveram extrusão do implante. MÉTODOS: Estudo retrospectivo, observacional, tendo sido avaliados 37 portadores de cavidade anoftálmica que tiveram extrusão do implante de cavidade, na Faculdade de Medicina de Botucatu-UNESP. RESULTADOS: As extrusões ocorreram em cavidades enucleadas ou evisceradas, a maioria delas submetidas a cirurgia em decorrência de phthisis bulbi ou trauma, em geral de 1 a 2 anos após a cirurgia inicial. A deiscência precedeu a extrusão em todos os casos, tendo a extrusão ocorrido com todos os tipos de implantes empregados. CONCLUSÃO: Após a colocação de implantes de cavidade podem ocorrer complicações. A deiscência e extrusão das esferas são possibilidades que podem requerer nova intervenção cirúrgica, para a qual o paciente e o oftalmologista devem estar preparados.PURPOSE: To evaluate the characteristics of patients with anophthalmic cavity who developed sphere extrusion. METHODS: A retrospective observational study was done evaluating 37 patients with anophthalmic cavity and sphere extrusion at the "Faculdade de Medicina de Botucatu-UNESP". RESULTS: Extrusion was observed in enucleated and eviscerated cavities. The majority of the patients had the eye removed because of phthisis bulbi or trauma and the extrusion happened 1 or 2 years after the surgery. Extrusion was preceded by conjunctival dehiscence and exposure of the sphere and occurred with all used implants. CONCLUSION: Complications after orbital implant placement are a possibility. Dehiscence and sphere extrusion may happen and another surgery would be necessary. The patient and the ophthalmologist have to be prepared for this.

  15. Twin- or single-screw extrusion of raw soybeans and preconditioned soybean meal and corn as individual ingredients or as corn-soybean product blends in diets for weanling swine.

    Science.gov (United States)

    Veum, T L; Serrano, X; Hsieh, F H

    2017-03-01

    Two 28-d experiments were conducted to evaluate the effects of extrusion of ground yellow corn, solvent-extracted soybean meal (SBM), and cracked whole soybeans (CWS) individually or as corn-soybean product blends on growth performance of weanling pigs. For Exp. 1, ground corn, SBM, and the corn-SBM blend were extruded at 137.5°C, 131.5°C, and 135.0°C, respectively, in a twin-screw extruder. Transit time was 60 s. Water was injected at 125 gmin during extrusion. The 5 treatments were the corn-SBM control diet and the diets with extruded (EX) corn + SBM, EX-SBM + corn, EX-corn + EX-SBM, and the EX-blend of corn-SBM. Ninety crossbred pigs with an initial average BW of 5.98 kg were allotted to 9 treatment replications with a barrow and gilt per pen. For Exp. 2, ground corn was preconditioned with water (10.0% of corn weight), and SBM was preconditioned with water and soybean oil (each at 20.0% of SBM weight) before extrusion. Raw CWS were not preconditioned. The corn, SBM, CWS, corn-SBM blend, and corn-CWS blend were extruded at 113.0°C, 132.0°C, 132.0°C, 88.0°C, and 102°C, respectively, with a single-screw extruder. Transit time was 30 s. The 8 isocaloric treatments were the corn-SBM control diet and the diets with EX-corn + SBM, EX-SBM + corn, EX-corn + EX-SBM, the EX-blend of corn-SBM, EX-CWS + corn, EX-CWS + EX-corn, and the EX-blend of corn-CWS. A total of 296 crossbred pigs with an initial average BW of 6.56 kg were allotted to 10 treatment replications. Sex and pigs per pen (3 or 4) were equalized within replication. Results for both experiments indicate that single- or twin-screw extrusion of ground corn or SBM as individual ingredients or as corn-SBM blends in diets for weanling pigs did not improve 28-d growth performance. However, for Exp. 2 weanling pigs fed the diets with EX-CWS + corn and EX-CWS + EX-corn had greater ( < 0.01) ADG and G:F, respectively, than pigs fed the corn-SBM control diet. The extrusion temperature of 102°C for the corn

  16. Study on Energy Consumption Analysis Modeling and Simulation in the Extrusion Process%挤压过程能耗分析及建模仿真

    Institute of Scientific and Technical Information of China (English)

    蒋攀

    2015-01-01

    A problem of high energy consumption and serious heat loss exists in the aluminum extrusion process and the main factor is the inefficiency of the extruder.The study was based on 10MN extruder.Energy consumption model was established about the hydraulic system in the extrusion process.The energy transmission,conversion and consumption were analysed. the key components of energy consumption were summarized and the theoretical formulas of Energy consumption were also presented. Using AMESim software to establish the simulation model and the validity of the model was proved .Then energy curves was analysed in the extrusion process.The results indicated that the mainly energy loss came from overflow losses,which have theoretical significance for energy-saving and optimize design of extruder.%铝挤压工艺能耗高、热量损失严重,挤压机的工作效率不高是主要因素,以10 MN铝挤压机为研究对象,针对挤压过程液压系统进行能耗建模:分析系统的能量传输、能量转换及能量消耗,总结出关键的耗能元件,并给出相应的理论能耗公式;利用AMESim软件建立仿真模型,证明了模型的正确性,分析了挤压过程各元件的能耗曲线,结果表明溢流损失是主要的能量损失方式,这对于挤压机的节能优化具有理论指导意义。

  17. Extrusion Upsetting Multiple Processing in Sandglass Die

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new method of getting ultrafine grain size has been investigated, which is called "Extrusion Upsetting Multiple Processing in Sandglass Die" or "Sandglass Extrusion" (SE). Since the shape of tested billet can remain unchanged after SE, the billet can be extruded repeatedly in order to get large plastic strain. The ultrafine grain size can be obtained in the billet material due to the large plastic strain and the dynamic recrystallization during SE. The experiments on SE of Zn-5%Al alloy have been done. The SE technology, microstructures, microhardness and superplasticity of tested material after SE have been studied. The experimental results show that the equal-axial ultrafine microstructures can be introduced to the bulk test material during sandglass extrusion. The high strain rate superplasticity can be realized.

  18. Apical extrusion of debris and irrigants using ProTaper hand, M-two rotary and WaveOne single file reciprocating system: An ex vivo study

    Directory of Open Access Journals (Sweden)

    Abhishek Singh

    2015-01-01

    Full Text Available Aims: The purpose of this ex vivo study was to evaluate and compare the weight of debris and volume of irrigant extruded apically from teeth using different preparation techniques. Subjects and Methods: Thirty extracted human mandibular premolars with single canals and similar lengths were instrumented using hand ProTaper F2 (25, 0.08; Dentsply Maillefer, Ballaigues, Switzerland, M-two (25, 0.06; VDW, Munich, Germany and WaveOne Primary (25, 0.08; Dentsply Maillefer, Ballaigues, Switzerland. Debris and irrigant extruded during instrumentation were collected into preweighed Eppendorf tubes. The volume of the irrigant was measured, and then the tubes were stored in an incubator at 70°C for 2 days. The Eppendorf tubes were weighed to obtain the final weight when the extruded debris was included. Three consecutive weights were obtained for each tube. Statistical Analysis Used: Data were statistically analyzed by one-way analysis of variance and Student′s t-test. Results: There were no statistically significant differences among the groups. The WaveOne reciprocating system showed the maximum amount of apical extrusion of debris and irrigant among all the groups. The least amount of debris and irrigant was observed in ProTaper hand instrument (P > 0.05. Conclusion: All instrumentation techniques were associated with debris and irrigant extrusion.

  19. Physical and mathematical modelling of extrusion processes

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Gronostajski, Z.; Niechajowics, A.

    2000-01-01

    The main objective of the work is to study the extrusion process using physical modelling and to compare the findings of the study with finite element predictions. The possibilities and advantages of the simultaneous application of both of these methods for the analysis of metal forming processes...

  20. Physical and mathematical modelling of extrusion processes

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Gronostajski, Z.; Niechajowics, A.

    2000-01-01

    The main objective of the work is to study the extrusion process using physical modelling and to compare the findings of the study with finite element predictions. The possibilities and advantages of the simultaneous application of both of these methods for the analysis of metal forming processes...

  1. The working domain in reactive extrusion .2. The effect of the polymerization rate

    NARCIS (Netherlands)

    der Goot, A.J.van; Klaassens, S.A.; Janssen, L.P.B.M.

    1997-01-01

    This article describes the influence of the polymerization rate on the working domain of a counter-rotating twin-screw extruder used as a polymerization reactor. The rate of polymerization was varied by changing the maleic anhydride (Mah) content in the feed, which consisted of styrene, n-butylmetha

  2. The Working Domain in Reactive Extrusion. Part II : The Effect of the Polymerization Rate

    NARCIS (Netherlands)

    Goot, A.J. van der; Klaassens, S.A.; Janssen, L.P.B.M.

    1997-01-01

    This article describes the influence of the polymerization rate on the working domain of a counter-rotating twin-screw extruder used as a polymerization reactor. The rate of polymerization was varied by changing the maleic anhydride (Mah) content in the feed, which consisted of styrene, n-butylmetha

  3. Hydrostatic extrusion of magnesium alloys

    NARCIS (Netherlands)

    Sillekens, W.H.; Bohlen, J.

    2012-01-01

    This chapter deals with the capabilities and limitations of the hydrostatic extrusion process for the manufacturing of magnesium alloy sections. Firstly, the process basics for the hydrostatic extrusion of materials in general and of magnesium in particular are introduced. Next, some recent research

  4. Possibility of Extrusion of Wood Powders

    National Research Council Canada - National Science Library

    MIKI, Tsunehisa; TAKAKURA, Norio; IIZUKA, Takashi; YAMAGUCHI, Katsuhiko; KANAYAMA, Kouzou

    2003-01-01

    .... Effects of extrusion temperature, extrusion ratio, moisture content and particle size of the mixed wood powders on the flow characteristics, bending strength, hardness and bulk density of extruded...

  5. Continuous production of fenofibrate solid lipid nanoparticles by hot-melt extrusion technology: a systematic study based on a quality by design approach.

    Science.gov (United States)

    Patil, Hemlata; Feng, Xin; Ye, Xingyou; Majumdar, Soumyajit; Repka, Michael A

    2015-01-01

    This contribution describes a continuous process for the production of solid lipid nanoparticles (SLN) as drug-carrier systems via hot-melt extrusion (HME). Presently, HME technology has not been used for the manufacturing of SLN. Generally, SLN are prepared as a batch process, which is time consuming and may result in variability of end-product quality attributes. In this study, using Quality by Design (QbD) principles, we were able to achieve continuous production of SLN by combining two processes: HME technology for melt-emulsification and high-pressure homogenization (HPH) for size reduction. Fenofibrate (FBT), a poorly water-soluble model drug, was incorporated into SLN using HME-HPH methods. The developed novel platform demonstrated better process control and size reduction compared to the conventional process of hot homogenization (batch process). Varying the process parameters enabled the production of SLN below 200 nm. The dissolution profile of the FBT SLN prepared by the novel HME-HPH method was faster than that of the crude FBT and a micronized marketed FBT formulation. At the end of a 5-h in vitro dissolution study, a SLN formulation released 92-93% of drug, whereas drug release was approximately 65 and 45% for the marketed micronized formulation and crude drug, respectively. Also, pharmacokinetic study results demonstrated a statistical increase in Cmax, Tmax, and AUC0-24 h in the rate of drug absorption from SLN formulations as compared to the crude drug and marketed micronized formulation. In summary, the present study demonstrated the potential use of hot-melt extrusion technology for continuous and large-scale production of SLN.

  6. The Study on Design of Transport Screws of Twin Screw Food Extruder%双螺杆食品膨化机输送螺旋的设计研究

    Institute of Scientific and Technical Information of China (English)

    史建国; 徐刚; 梁力克

    2005-01-01

    在研究双螺杆食品膨化机螺旋送料的基础上,对双螺杆食品膨化机螺旋的设计理论进行了研究,建立了双螺杆螺旋的基本参数,提出了双螺杆螺旋的设计思路,这对双螺杆食品膨化机的性能及使用寿命是很重要的.

  7. Study of Effect on System Character by Structure Parameter of Twin-screw Extruder%结构参数对双螺杆挤压机系统特性影响的研究

    Institute of Scientific and Technical Information of China (English)

    李德溥; 郭建亮; 杨绮云; 徐克非

    2001-01-01

    本文以螺杆长径比,螺杆压缩段长径比,模口直径作为实验因素,以双螺杆挤压机的功率消耗为目标函数,通过实验研究了结构参数对双螺杆挤压机系统特性的影响.利用三维曲面图和等高线图分析各因素对目标函数的影响,得出各因素的最佳取值范围,并建立了目标函数的统计模型.

  8. Study on the flavones stability during the twin-screw extruded-expanding process of cereal foods%双螺杆挤压膨化谷物食品中黄酮稳定性的研究

    Institute of Scientific and Technical Information of China (English)

    刘学文; 蒋保林

    2006-01-01

    采用双螺杆挤压膨化机,以玉米粉和荞麦粉为主要原料,添加银杏黄酮,考察了机筒温度和螺杆转速对挤压膨化产品中黄酮含量的影响,得到了以下规律和结论:挤压产品中黄酮的含量随机筒温度的升高而降低,随螺杆转速的升高而增加;当黄酮的添加量为75mg/kg、物料湿度14%、机筒温度125℃、螺杆转速为275r/min时,挤压产品的口感和组织状态最佳.

  9. The comparative study of pressing and extrusion like processes of construction ceramic products in the Metropolitan Area of Cucuta; Estudio comparativo de las tecnicas de extrusion y prensado como procesos de conformado de productos ceramicos de construccion en el Area Metropolitana de Cucuta

    Energy Technology Data Exchange (ETDEWEB)

    Gelves, J. F.; Monroy, R.; Sanchez, J.; Ramirez, R. P.

    2013-02-01

    The present work studies the principal variables of control in the manufacturing process of construction pieces of the Metropolitan Area of San Jose de Cucuta by extrusion and pressing techniques for its forming. The investigation was taken out using clayey samples of the two principal geological formations of the region where the raw material is taken for processing at an industrial level. The clayey samples milling was made by dry means as well as by moisture means and its particle size was measured. Subsequently the forming process was taken over by using an hydraulic press and extruder with vacuum system , both equipment s at laboratory scale, the pieces shaped were dry and firing between 980 degree centigrade and 1180 degree centigrade at the end of the process the tests were made to determine water absorption, contraction and mass loss at the pieces firing. The study results left to see that the extrusion technique allowed a faster vitrification for the region's clay in comparing with the pressing technique, the contractions of drying and firing are less marked on the pressing techniques with standard deviations much lower than in extrusion. (Author) 13 refs.

  10. Equal Channel Angular Extrusion of AA 6063 Using Conventional Direct Extrusion Press

    Science.gov (United States)

    Liu, Cheng-Hsien; Lin, Hsin-Chih

    2015-11-01

    In the present work, an extrusion-equal channel angular extrusion (Ex-ECAE) process composed of two processes, extrusion and ECAE, is developed. The Ex-ECAE die contains three segments and is used directly in the conventional direct extrusion press to refine the microstructure, specifically the coarse grain layer (CGL) on the surface of the extrudate. The first segment in the die is designed to perform the normal extrusion process and the second and third segments to perform the process of ECAE. The study reveals that the CGL can be eliminated (refined) completely at the macroscale. At the microscale, the original grain is subdivided into subgrain, which contains many smaller cells. The results can be explained by the grain subdivision mechanism. The textures of the Ex-ECAE sample at various segments are measured using EBSD (Electron Backscatter Diffraction). The results reveal that the first segment of the Ex-ECAE sample has a perfect fiber texture which consists of a mixture of strong and weak fiber components. The texture of the second segment is a mixture of strong (1 1 0) [1 -2 1] and weak (0 1 1) [2 -1 0] fiber components. However, the main component of the second segment is a typical texture of the "alloy" or "brass" type. Finally, the texture of the extrudate (the third segment) is reversed to an incomplete fiber texture which consists of strong (0 0 1) [-1 -1 0] and weak (1 1 1) [1 -1 0].

  11. Optimal design of an extrusion process for a hinge bracket

    Energy Technology Data Exchange (ETDEWEB)

    Na, Geum Ju; Jang, Myung Geun; Kim, Jong Bong [Seoul National University, Seoul (Korea, Republic of)

    2016-05-15

    This study considers process design in forming a hinge bracket. A thin hinge bracket is typically produced by bending a sheet panel or welding a hollow bar into a sheet panel. However, the hinge bracket made by bending or welding does not have sufficient durability in severe operating conditions because of the stress concentration in the bended region or the low corrosion resistance of the welded region. Therefore, this study uses forming to produce the hinge bracket part of a foldable container and to ensure durability in difficult operating conditions. An extrusion process for a T-shaped hinge bracket is studied using finite element analysis. Preliminary analysis shows that a very high forging load is required to form the bracket by forging. Therefore, extrusion is considered as a candidate process. Producing the part through the extrusion process enables many brackets to be made in a single extrusion and through successive cutting of the extruded part, thereby reducing the manufacturing cost. The design focuses on reducing the extrusion load and on ensuring shape accuracy. An initial billet is designed to reduce the extrusion load and to obtain a geometrically accurate part. The extruded part is bent frequently because of uneven material flow. Thus, extrusion die geometries are designed to obtain straight parts.

  12. A 3D FEM simulation study on the isothermal extrusion of a 7075 aluminium billet with a predetermined non-linear temperature distribution

    Science.gov (United States)

    Li, L.; Zhou, J.; Duszczyk, J.

    2003-05-01

    In this paper, computer simulations were performed on the extrusion of 7075 aluminium billets with non-uniform temperature distributions in order to inhibit excessive temperature rise that tends to occur during the conventional extrusion of a uniformly preheated billet. The simulations showed that when a linear temperature distribution was imposed on a billet with its rear end 150°C colder than its front end, the maximum temperature of the workpiece would still increase from 450°C to over 520°C at the end of an extrusion cycle, giving rise to hot shortness. Assigning a non-linear temperature distribution during preheating the billet could however significantly lessen this undesirable temperature increase, leading to isothermal extrusion. Such a non-linear temperature distribution was determined on the basis of the results obtained from the simulation of the extrusion of a billet with a linear temperature distribution. With this predetermined non-linear temperature distribution, the maximum temperature of the workpiece remained stable near the die entrance. The radial temperature variation on the cross-section of the extrudate became less significant as the material flowed through the die. In addition, the simulations showed another advantage of isothermal extrusion, i.e. an invariable die face pressure throughout an extrusion cycle. The maximum positive (tensile) principle stress was revealed at the corner of the die orifice, indicating that tearing tended to occur there.

  13. Heat Treated AZ61 Magnesium Alloy Obtained by Direct Extrusion and Continuous Rotary Extrusion Process

    Directory of Open Access Journals (Sweden)

    Bigaj M.

    2016-03-01

    Full Text Available The results of studies carried out on the heat treated AZ61 magnesium alloy extruded by two methods, i.e. direct extrusion and continuous rotary extrusion, were presented. As part of the work, parameters of the T6 heat treatment were proposed and aging curves were plotted. The solution heat treatment process was accompanied by the grain growth. During artificial aging, due to the decomposition of solid solution, the β-Mg17Al12 phase was precipitated from the supersaturated α solution. It precipitated in a coagulated form at the grain boundaries and in the form of fine-dispersed plates arranged in a preferred direction relative to the grain orientation. Rods obtained by continuous rotary extrusion, unlike those made by the direct process, exhibited a low degree of texturing and lack of anisotropic properties.

  14. EXTRUSION DIE CAE OF THE STEEL REINFORCED PLASTIC PIPE

    Institute of Scientific and Technical Information of China (English)

    W.Q. Ma; H.Y. Sun; D.C. Kang; K.D. Zhao

    2004-01-01

    The steel reinforced plastic pipe is a new kind of pressure pipe. It is made up with steel wires and plastic. Because reinforced skeleton of the steel wire increase the complexity of plastic flow during the extrusion phase, the traditional design criteria of extrusion die is not suitable. The study on extrusion die of the kind of pipe is very important step in produce development. Using finite element (FE) method in this paper, the flow rule of molten plastic inside the die has been predicted and a group of optimal structural parameters was obtained. These results are helpful for reducing the design cycle and improve the quality of the final product.

  15. Calibrator device for the extrusion of cable coatings

    Science.gov (United States)

    Garbacz, Tomasz; Dulebová, Ľudmila; Spišák, Emil; Dulebová, Martina

    2016-05-01

    This paper presents selected results of theoretical and experimental research works on a new calibration device (calibrators) used to produce coatings of electric cables. The aim of this study is to present design solution calibration equipment and present a new calibration machine, which is an important element of the modernized technology extrusion lines for coating cables. As a result of the extrusion process of PVC modified with blowing agents, an extrudate in the form of an electrical cable was obtained. The conditions of the extrusion process were properly selected, which made it possible to obtain a product with solid external surface and cellular core.

  16. Influence of Screw Elements of Co-rotating Twin Screw Extruder on Melt Grafting of PE-LD-g-MAH by Reactive Extrusion%同向双螺杆挤出机螺杆元件对PE-LD-g-MAH熔融接枝过程的影响

    Institute of Scientific and Technical Information of China (English)

    操彬; 马秀清; 方辉; 周新慧

    2006-01-01

    通过改变同向双螺杆挤出机主反应区的螺杆元件,研究了螺杆元件对由过氧化二异丙苯引发,低密度聚乙烯(PE-LD)熔融接枝马来酸酐(MAH)的接枝产物和接枝率的影响.红外光谱分析证实有部分MAH已经成功接枝到PE-LD分子链上.通过对挤出沿程4个在线取样位置样品的对比分析表明,具有高剪切性能的捏合盘元件的沿程样品的接枝率较大,熔体流动速率较小;具有高拉伸性能的S形元件能够迅速提高接枝率.

  17. 双螺杆挤压工艺对大麦面粉中水溶性戊聚糖含量的影响%Effects of Twin - screw Extrusion Processing on the Contents of Water - soluble Pentosans (WSP) in Barley Flour

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    本文探讨了双螺杆挤压机在不同的工艺条件下对两种大麦CDC Candle(以含蜡质淀粉为主)和Phoenix(以含普通淀粉为主)面粉中的水溶性戊聚糖(WSP)含量的影响,以及不同温度(30、45、65和85℃)段下WSP含量的变化.经挤压处理后面粉中的WSP明显高于没有经挤压处理的面粉,在CDC Candle大麦面粉中WSP的含量随着挤压的温度和湿度增大而增加,但在Phoenix面粉中WSP的含量随着挤压的温度的上升而有降低的趋势.经分析表明戊聚糖的水溶性越小,其阿拉伯糖与木糖(A/X)之比值越小.在未经挤压处理的面粉中,CDCCandle大麦面粉中所含的膳食纤维、β-葡聚糖和戊聚糖的含量均高于Phoenix大麦面粉.

  18. 双螺杆挤压工艺参数对模头压力及白高粱粉挤压产品品质特性的影响%Effect of process parameters of twin-screw extrusion on die pressure and the quality properties of white sorghum-based expanded products

    Institute of Scientific and Technical Information of China (English)

    刘明; 刘艳香; 张敏; 谭斌; 谭洪卓; 田晓红

    2009-01-01

    以去皮食用白高梁粉为原料,应用双螺杆挤压技术,研究了Ⅳ区温度、物料水分、喂料速度、螺杆转速等工艺参数对模头压力及产品品质特性的影响规律.结果表明:工艺参数对模头压力的影响显著(P<0.05);Ⅳ区温度对产品的水溶性指数、蛋白体外消化率的影响,水分对膨化度、容重、水溶性指数和蛋白体外消化率的影响,喂料速度对产品的各项品质特性的影响以及螺杆转速对容重、水溶性指数的影响均显著(P<0.05).在单因素实验条件下,工艺参数分别在Ⅳ区温度150℃、物料水分17%、喂料速度300g/min、螺杆转速275r/min时,产品的蛋白体外消化率均达到最大值,并且产品的其它品质特性均较好.

  19. Study of mechanical properties on powdermetalurgy aluminium matrix composites fabricated by stamping or extrusion; Estudio de las propiedades mecanicas en materiales compuestos de matriz aluminio pulvimetalurgicos conformados mediante forja o extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Busquets, D.; Gomez, L.; Amigo, V.; Salvador-Moya, M. D.

    2005-07-01

    We have developed composite materials from AA6061 aluminium alloy powders used as matrix and ceramics powders of boron carbide, silicon carbide and boron nitride, used as reinforcements in 2.5, 5.0, 7.5 and 10% vol. by mechanical mixing and milling in planetary mill at 360 rpm vial velocity for 4 h followed of hot stamping and extrusion process on green compacts. Mechanical properties obtained from tensile tests are influenced by the heat treatment, reinforcement fractions and nature. Moreover, these mechanical characteristic are dependent from the processing route. Optical and Scanning Electron Microscopy analysis revealed the microstructure of materials and let describe the tripartite relation; structure-processing-properties, of the developed materials. (Author) 20 refs.

  20. Epithelial cell extrusion leads to breaches in the intestinal epithelium.

    Science.gov (United States)

    Liu, Julia J; Davis, Elisabeth M; Wine, Eytan; Lou, Yuefei; Rudzinski, Jan K; Alipour, Misagh; Boulanger, Pierre; Thiesen, Aducio L; Sergi, Consolato; Fedorak, Richard N; Muruve, Daniel; Madsen, Karen L; Irvin, Randall T

    2013-04-01

    Two distinct forms of intestinal epithelial cell (IEC) extrusion are described: 1 with preserved epithelial integrity and 1 that introduced breaches in the epithelial lining. In this study, we sought to determine the mechanism underlying the IEC extrusion that alters the permeability of the gut epithelium. IEC extrusions in polarized T84 monolayer were induced with nigericin. Epithelial permeability was assessed with transepithelial electrical resistance and movements of latex microspheres and green fluorescent protein-transfected Escherichia coli across the monolayer. In vivo IEC extrusion was modulated in wild-type and a colitic (interleukin-10 knock-out) mouse model with caspase-1 activation and inhibition. Luminal aspirates and mucosal biopsies from control patients and patients with inflammatory bowel disease were analyzed for caspase-1 and caspase-3&7 activation. Caspase-1-induced IEC extrusion in T84 monolayers resulted in dose-dependent and time-dependent barrier dysfunction, reversible with caspase-1 inhibition. Moreover, the movements of microspheres and microbes across the treated epithelial monolayers were observed. Increased caspase-1-mediated IEC extrusion in interleukin-10 knock-out mice corresponded to enhanced permeation of dextran, microspheres, and translocation of E. coli compared with wild type. Caspase-1 inhibition in interleukin-10 knock-out mice resulted in a time-dependent reduction in cell extrusion and normalization of permeability to microspheres. Increased IEC extrusion in wild-type mice was induced with caspase-1 activation. In human luminal aspirates, the ratio of positively stained caspase-1 to caspase-3&7 cells were 1:1 and 2:1 in control patients and patients with inflammatory bowel disease, respectively; these observations were confirmed by cytochemical analysis of mucosal biopsies. IEC extrusion mediated by caspase-1 activation contributes to altered intestinal permeability in vitro and in vivo.

  1. Effect of extrusion parameters on some properties of dietary fiber ...

    African Journals Online (AJOL)

    use

    2011-11-21

    Nov 21, 2011 ... The independent variables studied were extrusion temperature (from. 59.77 to ... The extraction of juice from citrus fruits, such as oranges, grapefruit ..... properties of extruded orange pulp and its effect on the quality of cookies.

  2. Investigation on Effects of Die Orifice Layout on Three-Hole Porthole Extrusion of Aluminum Alloy 6063 Tubes

    Science.gov (United States)

    Zhang, Cunsheng; Zhao, Guoqun; Chen, Hao; Guan, Yanjin; Cai, Haijin; Gao, Baojie

    2013-05-01

    Currently, with the increasing demand of high production output, much attention is paid to the research and development of multi-hole extrusion die. However, owing to the complexity of multi-hole porthole extrusion technology, it has not been applied widely in practice for the production of aluminum profiles, especially for porthole die with an odd number of die orifices. The purpose of this study is to design a three-hole porthole die for producing an aluminum tube and to optimize the location of die orifices based on computer-aided design and engineering. First, three-hole extrusion dies for different locations of die orifices are designed. Then, extrusion processes with different multi-hole porthole dies are simulated by means of HyperXtrude. Through numerical simulation, metal flow, temperature distribution, welding pressure, extrusion load, and die stress, etc. could be obtained, and the effects of the location of die orifices on extrusion process are investigated. With the increasing distance between die orifice and extrusion center (described as eccentricity ratio), metal flow becomes nonhomogeneous, and twisting or bending deformation of profile occurs, but the welding pressure rises, which improves the welding quality of profiles. However, the required extrusion force, billet and die temperature, die displacement, and stress induce no significant changes. In comparison with the extrusion force during single-hole porthole extrusion, there is 18.5% decrease of extrusion force during three-hole porthole extrusion. Finally, design rules for this kind of multi-hole extrusion dies are summarized.

  3. Advanced surface chemical analysis of continuously manufactured drug loaded composite pellets

    OpenAIRE

    2016-01-01

    The aim of the present study was to develop and characterise polymeric composite pellets by means of continuous melt extrusion techniques. Powder blends of a steroid hormone (SH) as a model drug and either ethyl cellulose (EC N10 and EC P7 grades) or hydroxylpropyl methylcellulose (HPMC AS grade) as polymeric carrier were extruded using a Pharma 11 mm twin screw extruder in a continuous mode of operation to manufacture extruded composite pellets of 1 mm length. Molecular modelling study using...

  4. Hot melt extrusion for amorphous solid dispersions: temperature and moisture activated drug-polymer interactions for enhanced stability.

    Science.gov (United States)

    Sarode, Ashish L; Sandhu, Harpreet; Shah, Navnit; Malick, Waseem; Zia, Hossein

    2013-10-07

    Hot melt extrudates (HMEs) of indomethacin (IND) with Eudragit EPO and Kollidon VA 64 and those of itraconazole (ITZ) with HPMCAS-LF and Kollidon VA 64 were manufactured using a Leistritz twin screw extruder. The milled HMEs were stored at controlled temperature and humidity conditions. The samples were collected after specified time periods for 3 months. The stability of amorphous HMEs was assessed using moisture analysis, thermal evaluation, powder X-ray diffraction, FTIR, HPLC, and dissolution study. In general, the moisture content increased with time, temperature, and humidity levels. Amorphous ITZ was physically unstable at very high temperature and humidity levels, and its recrystallization was detected in the HMEs manufactured using Kollidon VA 64. Although physical stability of IND was better sustained by both Eudragit EPO and Kollidon VA 64, chemical degradation of the drug was identified in the stability samples of HMEs with Eudragit EPO stored at 50 °C. The dissolution rates and the supersaturation levels were significantly decreased for the stability samples in which crystallization was detected. Interestingly, the supersaturation was improved for the stability samples of IND:Eudragit EPO and ITZ:HPMCAS-LF, in which no physical or chemical instability was observed. This enhancement in supersaturation was attributed to the temperature and moisture activated electrostatic interactions between the drugs and their counterionic polymers.

  5. Noise-induced variability of volcanic extrusions

    Science.gov (United States)

    Alexandrov, D. V.; Bashkirtseva, I. A.; Ryashko, L. B.

    2016-11-01

    Motivated by important physical applications, we study a non-linear dynamics of volcanic extrusions on the basis of a simple pressure-mass flow model. We demonstrate that the deterministic phase portrait represents either the bulbous-type curves or closed paths stretched to their left depending on the initial conditions. The period of phase trajectories therewith increases when the pressure drop between the conduit top and bottom compensates the lava column pressure in it. Stochastic forcing changes the system dynamics drastically. We show that a repetitive scenario of volcanic behaviour with intermittency of stochastic oscillations of different extrusion amplitudes and frequencies appears in the presence of noises. As this takes place, the mean values of interspike intervals characterizing the system periodicity have a tendency to grow with increasing the noise intensity. The probability distribution functions confirming this dynamic behaviour are constructed.

  6. Validation of an in-line Raman spectroscopic method for continuous active pharmaceutical ingredient quantification during pharmaceutical hot-melt extrusion.

    Science.gov (United States)

    Saerens, L; Segher, N; Vervaet, C; Remon, J P; De Beer, T

    2014-01-02

    A calibration model for in-line API determination was developed based on Raman spectra collected during hot-melt extrusion. This predictive model was validated by calculating the accuracy profile based on the analysis results of validation experiments. Furthermore, based on the data of the accuracy profile, the measurement uncertainty was determined. Finally, the robustness of the model was evaluated. A Raman probe was implemented in the die of a twin-screw extruder, to monitor the drug concentration during extrusion of physical mixtures containing 15, 20, 25, 30 and 35% (w/w) metoprolol tartrate (MPT) in Eudragit(®) RS PO, an amorphous copolymer of acrylic and methacrylic acid esters with a low content of quaternary ammonium groups, which are present as salts. Several different calibration models for the prediction of the MPT content were developed, based on the use of single spectra or averaged spectra, and using partial least squares (PLS) regression or multivariate curve resolution (MCR). These predictive models were validated by extruding and monitoring mixtures containing 17.5, 22.5, 25.0, 27.5 and 32.5% (w/w) MPT. Each validated concentration was monitored on three different days, by two different operators. The β-expectation tolerance intervals were calculated for each model and for each of the validated MPT concentration levels (β was set at 95%), and acceptance limits were set at 10% (relative bias), indicating that at least 95% of future measurements should not deviate more than 10% from the true value. The only model where these acceptance limits were not exceeded was the MCR model based on averaged Raman spectra. The uncertainty measurements for this model showed that the unknown true value can be found at a maximum of ±7.00% around the measured result, with a confidence level of 95%. The robustness of this model was evaluated via an experimental design varying throughput, screw speed and barrel temperature. The robustness designs showed no

  7. The effect of gas assisted length on polymer melt extrusion based on the gas-assisted extrusion technique

    Science.gov (United States)

    Wan, B.; Ren, Z.; Liu, G. D.; Huang, X. Y.

    2017-02-01

    In this study, the gas-assisted technique was used into the process of polymer melt extrusion to overcome the extrudate swell problem. The gas length is an important factors in the gas-assisted extrusion technique. To ascertain the mechanism of the gas-assisted extrusion technique, and to determine the optimal gas length, the effect of gas length on the extrudate swell ratio of melt was numerically investigated. In finite element numerical simulation, PTT constitutive model and full slip boundary condition were used to achieve the gas-assisted mode. Compared with the traditional no gas-assisted extrusion, numerical results showed that the extrudate swell problem was well eliminated by the gas-assisted method. Moreover, the extrudate swell of melt decreased with the increasing of the gas length because the pressure and shear stress of melt were greatly decreased. Moreover, the flow velocity of melt is uniform at the die outlet.

  8. Contrôle et stabilisation de morphologies de mélanges Polyamide 6 / Polyéthylène Haute Densité compatibilisés par voie réactive

    OpenAIRE

    Argoud, Alexandra,

    2011-01-01

    This study deals with reactively compatibilized Polyamide 6 / High Density Polyethylene blends. More precisely, it focuses on the relationship between (1) the formulation, the processing parameters in corotating twin screw extrusion and (2) the morphologies and the microstructures of blends. Multi-scale morphologies were observed by Scanning and Transmission Electron Microscopy. At the micron scale, the following morphologies were developed: nodular dispersions, stretched nodules and co-conti...

  9. Experimental and numerical investigation of ram extrusion of bread dough

    Science.gov (United States)

    Mohammed, M. A. P.; Wanigasooriya, L.; Charalambides, M. N.

    2016-10-01

    An experimental and numerical study on ram extrusion of bread dough was conducted. A laboratory ram extrusion rig was designed and manufactured, where dies with different angles and exit radii were employed. Rate dependent behaviour was observed from tests conducted at different extrusion speeds, and higher extrusion pressure was reported for dies with decreasing exit radius. A finite element simulation of extrusion was performed using the adaptive meshing technique in Abaqus. Simulations using a frictionless contact between the billet and die wall showed that the model underestimates the response at high entry angles. On the other hand, when the coefficient of friction value was set to 0.09 as measured from friction experiments, the dough response was overestimated, i.e. the model extrusion pressure was much higher than the experimentally measured values. When a critical shear stress limit, τmax, was used, the accuracy of the model predictions improved. The results showed that higher die angles require higher τmax values for the model and the experiments to agree.

  10. Oral transmucosal delivery of domperidone from immediate release films produced via hot-melt extrusion technology.

    Science.gov (United States)

    Palem, Chinna Reddy; Kumar Battu, Sunil; Maddineni, Sindhuri; Gannu, Ramesh; Repka, Michael A; Yamsani, Madhusudan Rao

    2013-02-01

    The objective of the study was to prepare and characterize the domperidone (DOM) hot-melt extruded (HME) buccal films by both in vitro and in vivo techniques. The HME film formulations contained PEO N10 and/or its combination with HPMC E5 LV or Eudragit RL100 as polymeric carriers, and PEG3350 as a plasticizer. The blends were co-processed at a screw speed of 50 rpm with the barrel temperatures ranging from 120-160°C utilizing a bench top co-rotating twin-screw hot-melt extruder using a transverse-slit die. The HME films were evaluated for drug content, drug excipient interaction, in vitro drug release, mechanical properties, in vivo residence time, in vitro bioadhesion, swelling and erosion, ex vivo permeation from HME films and the selected optimal formulation was subjected for bioavailability studies in healthy human volunteers. The extruded films demonstrated no drug excipient interaction and excellent content uniformity. The selected HME film formulation (DOM2) exhibited a tensile strength (0.72 Kg/mm(2)), elongation at break (28.4% mm(2)), in vivo residence time (120 min), peak detachment force (1.55 N), work of adhesion (1.49 mJ), swelling index (210.2%), erosion (10.5%) and in vitro drug release of 84.8% in 2 h. Bioavailability from the optimized HME buccal films was 1.5 times higher than the oral dosage form and the results showed statistically significant (p < 0.05) difference. The ex vivo-in vivo correlation was found to have biphasic pattern and followed type A correlation. The results indicate that HME is a viable technique for the preparation of DOM buccal-adhesive films with improved bioavailability characteristics.

  11. OPTIMIZING AN ALUMINUM EXTRUSION PROCESS

    Directory of Open Access Journals (Sweden)

    Mohammed Ali Hajeeh

    2013-01-01

    Full Text Available Minimizing the amount of scrap generated in an aluminum extrusion process. An optimizing model is constructed in order to select the best cutting patterns of aluminum logs and billets of various sizes and shapes. The model applied to real data obtained from an existing extrusion factory in Kuwait. Results from using the suggested model provided substantial reductions in the amount of scrap generated. Using sound mathematical approaches contribute significantly in reducing waste and savings when compared to the existing non scientific techniques.

  12. Extrusion processing : effects on dry canine diets

    NARCIS (Netherlands)

    Tran, Q.D.

    2008-01-01

    Keywords: Extrusion, Canine diet, Protein, Lysine, Starch gelatinization, Palatability, Drying. Extrusion cooking is a useful and economical tool for processing animal feed. This high temperature, short time processing technology causes chemical and physical changes that alter the nutritional and

  13. The reactive extrusion of thermoplastic polyurethane

    NARCIS (Netherlands)

    Verhoeven, Vincent Wilhelmus Andreas

    2006-01-01

    The objective of this thesis was to increase the understanding of the reactive extrusion of thermoplastic polyurethane. Overall, several issues were identified: • Using a relative simple extrusion model, the reactive extrusion process can be described. This model can be used to further investigate a

  14. Temperature window effect and its application in extrusion of ultrahigh molecular weight polyethylene

    Directory of Open Access Journals (Sweden)

    2011-08-01

    Full Text Available Ultrahigh molecular weight polyethylene (UHMWPE was ram extruded using a temperature window effect. The extrusion pressure abruptly drops at a very narrow extrusion temperature window which is about 10°C higher than the theoretical melting point of orthorhombic polyethylene crystals under quiescent and equilibrium states. The correlation between extrusion pressure and parameters such as extrusion temperature, annealing condition, thermal history, piston velocity, L/D ratio of the die, and molecular weight of UHMWPE, was studied. The temperature window increases with molecular weight and is unaffected by thermal history and annealing. The stable extrusion pressure and the critical piston velocity decrease with the rise in the extrusion temperature. The flow resistance reversely depends on the L/D ratio of the die. This phenomenon is attributed to an extensional flow-induced chain alignment along the streamline, which results in the formation of a metastable mesophase with higher chain mobility.

  15. Studies on Microstructure and Thermoelectric Properties of p-Type Bi-Sb-Te Based Alloys by Gas Atomization and Hot Extrusion Processes

    Science.gov (United States)

    Park, Ki-Chan; Madavali, Babu; Kim, Eun-Bin; Koo, Kyung-Wan; Hong, Soon-Jik

    2016-10-01

    p-Type Bi2Te3 + 75% Sb2Te3 based thermoelectric materials were fabricated via gas atomization and the hot extrusion process. The gas atomized powder showed a clean surface with a spherical shape, and expanded in a wide particle size distribution (average particle size 50 μm). The phase of the fabricated extruded and R-extruded bars was identified using x-ray diffraction. The relative densities of both the extruded and R-extruded samples were measured by Archimedes principle with ˜98% relative density. The R-extruded bar exhibited finer grain microstructure than that of single extrusion process, which was attributed to a recrystallization mechanism during the fabrication. The R-extruded sample showed improved Vickers hardness compared to the extruded sample due to its fine grain microstructure. The electrical conductivity improved for the extruded sample whereas the Seebeck coefficient decreases due to its high carrier concentration. The peak power factor, ˜4.26 × 10-3 w/mK2 was obtained for the single extrusion sample, which is higher than the R-extrusion sample owing to its high electrical properties.

  16. Studies on Microstructure and Thermoelectric Properties of p-Type Bi-Sb-Te Based Alloys by Gas Atomization and Hot Extrusion Processes

    Science.gov (United States)

    Park, Ki-Chan; Madavali, Babu; Kim, Eun-Bin; Koo, Kyung-Wan; Hong, Soon-Jik

    2017-05-01

    p-Type Bi2Te3 + 75% Sb2Te3 based thermoelectric materials were fabricated via gas atomization and the hot extrusion process. The gas atomized powder showed a clean surface with a spherical shape, and expanded in a wide particle size distribution (average particle size 50 μm). The phase of the fabricated extruded and R-extruded bars was identified using x-ray diffraction. The relative densities of both the extruded and R-extruded samples were measured by Archimedes principle with ˜98% relative density. The R-extruded bar exhibited finer grain microstructure than that of single extrusion process, which was attributed to a recrystallization mechanism during the fabrication. The R-extruded sample showed improved Vickers hardness compared to the extruded sample due to its fine grain microstructure. The electrical conductivity improved for the extruded sample whereas the Seebeck coefficient decreases due to its high carrier concentration. The peak power factor, ˜4.26 × 10-3 w/mK2 was obtained for the single extrusion sample, which is higher than the R-extrusion sample owing to its high electrical properties.

  17. Stability of vitamins during extrusion.

    Science.gov (United States)

    Riaz, Mian N; Asif, Muhammad; Ali, Rashida

    2009-04-01

    Vitamins (fat and water soluble) are vital food ingredients for healthy living, required by our bodies for normal metabolism. These are present in most natural food in small quantities, but when we process food through thermal processing methods (especially extrusion) a reasonable amount of the present vitamins are lost. During extrusion, factors like barrel temperature, screw rpm, moisture of ingredients, die diameter, and throughput affect the retention of vitamins in food and feed. The vitamins most sensitive to the extrusion process are vitamin A and vitamin E from fat-soluble vitamins, and vitamin C, B(1), and folic acid from water-soluble vitamins. The other vitamins of the B group, such as B(2), B(6), B(12), niacin, Ca-pantothenate, and biotin, are stable. Vitamin E itself or in its complex form is quite unstable during processing and even in storage of extruded food. Ascorbic acid directly added or coated with fat and then added to feed during extrusion is also very unstable. Vitamins A, C, D, and E are also sensitive to oxidation, so these vitamins have minimum retention during storage of extruded food.

  18. Sodium hydroxide digestion of wolframite by reactive extrusion%反应挤出法碱分解黑钨矿

    Institute of Scientific and Technical Information of China (English)

    赵中伟; 梁勇; 刘旭恒; 李洪桂; 陈爱良; 梁新星

    2011-01-01

    A novel process was proposed to solve the current disadvantages of high reaction temperature and low productivity in the process of NaOH digestion of wolframite. With a reactor of twin screw extruder, the process of sodium hydroxide digestion of high-viscosity wolframite by reactive extrusion was investigated. The effects of leaching time, temperature, screw rotating speed and NaOH dosage on digestion of wolframite were systematically evaluated. Under the conditions of mass ratio of ore to water 2.67:1, NaOH dosage 1.5 times to stoichiometry, temperature 120 °C, screw rotating speed 180 r/min and reaction time 2.5 h, the content of WO3 in the residue and the WO3 extraction are 2.54% and 99.13%, respectively.%针对目前黑钨矿碱法分解工艺中存在的反应温度高、生产效率低等问题,开发了一种黑钨矿碱分解新工艺,以双螺杆挤出机为反应器,采用反应挤出法对高黏度黑钨矿的碱分解过程进行了研究,系统考察浸出时间、温度、螺杆转速和碱用量对钨矿浸出效果的影响.在矿水质量比为2.67∶1、碱用量为理论量的1.5倍、温度为120℃,螺杆转速为180 r/min和反应时间为2.5 h的条件下,浸出渣中WO3的含量为2.54%,钨矿的浸出率达99.13%.

  19. 挤压对小米淀粉理化特性的影响%Effect of extrusion on the physicochemical properties of foxtail millet starch

    Institute of Scientific and Technical Information of China (English)

    赵学伟; 魏益民; 张波

    2012-01-01

    采用双螺杆挤压机在5个套筒温度和物料水分水平下对小米进行挤压膨化,然后测定产品中淀粉的理化特性。结果表明:与物料水分相比套筒温度对小米淀粉糊化度的影响较大,而对水溶性糖含量的影响相反。V区温度从165℃升至180℃时糊化度明显降低,物料水分从15%升至21%时水溶性糖含量降低。与套筒温度相比物料水分对特征黏度影响较大,其值在单位机械能耗(SME)大于420W·h/kg时不再随SME增大而进一步降低。RVA测定结果也显示挤压导致淀粉糊化和降解;RVA黏度随套筒温度升高而升高,直至195℃;随物料水分含量升高而升高,直至21%。%Foxtail millet was extrusion- expanded with a twin- screw extruder at five barrel temperature (BTs) and feed moisture(FMs) levels.Then the physicochemical properties of starch in the extrudates were measured.The results showed that the BT gave a larger impact on the gelatinization degree than FM did.As for water-soluble sugar,FM gave a larger impact.The gelatinization degree decreased sharply with BT at V section increasing from 165℃ to 180℃The water-soluble sugar decreased with FM increasing from 15% to 21%.Compared with BT, FM had a bigger impact on the intrinsic viscosity,which did not decrease further when specific mechanical energy (SME)was beyond 420W · h/kg.RVA measurement also demonstrated that starch gelatinization and degradation occurred during extrusion.RVA viscosity increased with BT at V section until 195℃,and with FM until 21%.

  20. Rheological Study Of The Mixture Of Acetaminophen And Polyethylene Oxide For Hot-Melt Extrusion Application (PREPRINT)

    Science.gov (United States)

    2011-01-01

    effect . The edge effect becomes more severe as the shear rate increases [9]. The maximum torque for the oscillatory rheom- eter used in this study is...1500 g cm, while the edge effect is often manifested by the sudden drop of the torque. The viscosity in a capillary flow is calculated using following...application, Eur. J. Pharm. Biopharm. (2011), doi:10.1016/j.ejpb.2011.03.013The shear rate for the oscillatory rheometer is limited by the torque and edge

  1. Hot Extrusion of Aluminum Chips

    Science.gov (United States)

    Tekkaya, A. Erman; Güley, Volkan; Haase, Matthias; Jäger, Andreas

    The process of hot extrusion is a promising approach for the direct recycling of aluminum machining chips to aluminum profiles. The presented technology is capable of saving energy, as remelting of aluminum chips can be avoided. Depending on the deformation route and process parameters, the chip-based aluminum extradates showed mechanical properties comparable or superior to cast aluminum billets extruded under the same conditions. Using different metal flow schemes utilizing different extrusion dies the mechanical properties of the profiles extruded from chips can be improved. The energy absorption capacity of the profiles the rectangular hollow profiles extruded from chips and as-cast billets were analyzed using the drop hammer test set-up. The formability of the profiles extruded from chips and as-cast material were compared using tube bending tests in a three-roller-bending machine.

  2. Extrusion of ECC-Material

    DEFF Research Database (Denmark)

    Stang, Henrik; Li, Victor C.

    1999-01-01

    in recent years at Department of Civil and Envirionmetal Engineering, University of Michigan. These materials have been developed with the special aim of producing high performance , strain hardening materials with low volume concentrations of short fibers in a cementitious material.ECC material spcimens...... have until now been produced by traditional casting processes. In the present paper results from a recent collaborative reserach project are documented - demonstrating that ECC materials can be extruded in the process referred to above.......An extrusion process especially designed for extrusion of pipes made from fiber reinforced cementitious materials has been developed at Department of Structural Engineering and Materials at the Technical University of DenmarkEngineered Cementitious Composite (ECC) materials have been developed...

  3. 温挤压模具热处理工艺研究%A Study of Heat Treatment Process of Warm Extrusion Mold

    Institute of Scientific and Technical Information of China (English)

    曹治国

    2012-01-01

    With the application of warm extrusion technique in small and medium - sized enterprises, highspeed steel W6Mo5Cr4V2, which features high strength, good wear resistance and red hardness, is widely used as a material for warm extrusion mold. According to the char- acteristics of warm extrusion mold and in view of the shortcomings of high - speed steel W6MoSCr4V2, such as thickness of carbide, easy oxidation and decarbonization, and poor toughness, we established a reasonable technical route by applying blank forging technique and vacuum heat treatment.%随着温挤压技术在中小企业应用推广,具有强度高、耐磨性好、热硬性好的高速钢W6MoSCr4V2被广泛用作温挤压模具材料.根据温挤压模具特点和W6M05Cr4V2高速钢碳化物粗大,易于氧化脱碳,韧度较差的缺点,运用毛坯锻造工艺和真空热处理技术,制定出了合理的工艺路线.

  4. Factors affecting irrigant extrusion during root canal irrigation: a systematic review

    NARCIS (Netherlands)

    Boutsioukis, C.; Psimma, Z.; Sluis, van der L.W.M.

    2013-01-01

    The aim of the present study was to conduct a systematic review and critical analysis of published data on irrigant extrusion to identify factors causing, affecting or predisposing to irrigant extrusion during root canal irrigation of human mature permanent teeth. An electronic search was conducted

  5. Factors affecting irrigant extrusion during root canal irrigation: a systematic review

    NARCIS (Netherlands)

    Boutsioukis, C.; Psimma, Z.; van der Sluis, L.W.M.

    2013-01-01

    The aim of the present study was to conduct a systematic review and critical analysis of published data on irrigant extrusion to identify factors causing, affecting or predisposing to irrigant extrusion during root canal irrigation of human mature permanent teeth. An electronic search was conducted

  6. FEM and FVM compound numerical simulation of aluminum extrusion processes

    Institute of Scientific and Technical Information of China (English)

    周飞; 苏丹; 彭颖红; 阮雪榆

    2003-01-01

    The finite element method (FEM) and the finite volume method (FVM) numerical simulation methods have been widely used in forging industries to improve the quality of products and reduce the costs. Because of very concentrative large deformation during the aluminum extrusion processes, it is very difficult to simulate the whole forming process only by using either FEM or FVM. In order to solve this problem, an FEM and FVM compound simulation method was proposed. The theoretical equations of the compound simulation method were given and the key techniques were studied. Then, the configuration of the compound simulation system was established. The tube extrusion process was simulated successfully so as to prove the validity of this approach for aluminum extrusion processes.

  7. Parametric Optimization of Simulated Extrusion of Square to Square Section Through Linear Converging Die

    Science.gov (United States)

    Mohapatra, S. K.; Maity, K. P.

    2016-02-01

    The effect of various process parameters for determining extrusion load has been studied for square to square extrusion of Al-6061 alloy, a most used aluminium alloy series in forming industries. Parameters like operating temperature, friction condition, ram velocity, extrusion ratio and die length have been chosen as an input variable for the above study. Twenty five combinations of parameters were set for the investigation by considering aforementioned five parameters in five levels. The simulations have been carried out by Deform-3D software for predicting maximum load requirement for the complete extrusion process. Effective stress and strain distribution across the billet has been checked. Operating temperature, extrusion ratio, friction factor, ram velocity and die length have the significant effect in decreasing order on the maximum load requirement.

  8. Chemical changes during extrusion cooking. Recent advances.

    Science.gov (United States)

    Camire, M E

    1998-01-01

    Cooking extruders process a variety of foods, feeds, and industrial materials. Greater flexibility in product development with extruders depends upon understanding chemical reactions that occur within the extruder barrel and at the die. Starch gelatinization and protein denautration are the most important reactions during extrusion. Proteins, starches, and non-starch polysaccharides can fragment, creating reactive molecules that may form new linkages not found in nature. Vitamin stability varies with vitamin structure, extrusion conditions, and food matrix composition. Little is known about the effects of extrusion parameters on phytochemical bioavailability and stability. Reactive extrusion to create new flavor, antioxidant and color compounds will be an area of interest in the future.

  9. 挤压膨化对绿茶茶渣中没食子酸影响实验研究%Experimental Research of Influence of Extrusion Parameters on Crude Fiber in the Green Tea Leaves

    Institute of Scientific and Technical Information of China (English)

    王博; 周小芬; 叶阳; 朱宏凯; 董春旺; 钱园凤

    2014-01-01

    Researcher extruded green tea-leaves with DS30-III twin-screw extruder. According to single factor investigation, the mathematical models with the content of Gallic acid as the responses to moisture content of material, feeding speed, rotational speed of screw and temperature of barrel were established by using response surface design. It was followed by response surface analysis. The results showed that the optimal extrusion parameters of high content of Gallic acid in green tea-leaves were that moisture content of material was 70%, feeding speed rotational was 58 r/min, speed of screw was 60 r/min and temperature of barrel was 60 ℃. The significance of parameters on the content of Gallic acid in green tea-leaves was decreased according to the ranking of moisture content of material> rotational speed of screw>temperature of barrel>feeding speed. The content of Gallic acid in the tea-leaves that is dealt with optimal extrusion parameters was 3.57 mg/g , compared with the raw materials before extrusion;the content of Gallic acid had a increase of 2.69 mg/g.%利用DS30-III型双螺杆挤压膨化机对绿茶茶渣进行挤压膨化加工,在单因素试验的基础上,选取了物料含水量、喂料速度、螺杆转速、套筒温度为影响因子,以绿茶茶渣中没食子酸为响应面值,应用响应面设计方法建立数学模型,进行响应面分析。结论表明,获得高没食子酸含量的最佳工艺参数为:物料含水量70%,喂料速度58 r/min,螺杆转速60 r/min,套筒温度60℃。挤压膨化参数对没食子酸含量影响的大小依次为:物料含水量>螺杆转速>套筒温度>喂料速度。经过最佳挤压膨化参数处理的绿茶茶渣中没食子酸含量为3.57 mg/g,与原料相比,没食子酸含量增加2.69 mg/g。

  10. Interference of processing variables on the mechanical behavior of nano composites HDPE/clay; Interferencia das variaveis de processamento no comportamento mecanico de nanocompositos PEAD/argila

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, R. [Universidade Federal do Piaui, Teresina, PI (Brazil); Souza, D.D.; Nobrega, K.C.; Araujo, E.M.; Melo, T.J. [Universidade Federal de Campina Grande - UAEMa Campina Grande, PB (Brazil)

    2010-07-01

    Nano composites were processed using the technique of melt intercalation, starting from a concentrated polar compatibilizer / organo clay (PE-g-MA / organo clay) prepared in an internal mixer. The concentrate was incorporated into the matrix of PEAD by two methods: (I) twin screw contrarrotational extruder and (II) twin screw corrotational extruder, using two thread profiles (ROS and 2KB90), after extrusion, the specimens of the extruded composites were injection molded. The diffraction of X-ray was used to analyze the degree of expansion of the clays prepared, and the degree of exfoliation of nano composites developed. The interference of processing variables on mechanical properties was studied by the behavior of the modulus and tensile strength of nano composite systems. Observed similar behavior in the use of thread (or 2KB90 ROS) of the nano composites, with a reduction in modulus and tensile strength. (author)

  11. Process optimization diagram based on FEM simulation for extrusion of AZ31 profile

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The ram speed and the billet temperature are the primary process variables that determine the quality of the extruded magnesium profile and the productivity of the extrusion operation.The optimization of the extrusion process concerns the interplay between these two variables in relation to the extrudate temperature and the peak extrusion pressure The 3D computer simulations were performed to determine the eriects of the ram speed and the billet temperature on the extrudate temperature and the peak extrusion pressure,thereby providing guidelines for the process optimization and minimizing the number of trial extrusion runs needed for the process optimization.A case study on the extrusion of an AZ31 X-shaped profile was conducted.The correlations between the process variables and the response from the deformed material,extrudate temperature and peak extrusion pressure,were established from the 3D FEM simulations and verified by the experiment.The research opens up a way to rational selection of the process variables for ensured quality and maximum productivity of the magnesium extrusion.

  12. Determination of cordycepin content of Cordyceps militaris ...

    African Journals Online (AJOL)

    recombinant rice by high performance liquid chromatography ... caterpillar fungus culture medium powder using twin-screw extrusion technology. ... HPLC analysis was carried out in high ... culture medium: 20 %; total moisture content: 40.

  13. Block copolymers of poly(L-lactide) and poly(ε-caprolactone) or poly(ethylene glycol) prepared by reactive extrusion

    NARCIS (Netherlands)

    Stevels, W.M.; Bernard, A.; Witte, van de P.; Dijkstra, P.J.; Feijen, J.

    1996-01-01

    Blends of poly(L-lactide) (PLLA) and poly(-caprolactone) (PCL) were prepared in a co-rotating twin screw miniextruder (40 rpm, 200°). It was attempted to prepare multiblock copolymers by allowing a controlled number of transesterification reactions. Various cat-alysts (n-Bu3SnOMe, Sn(Oct)2, Ti(OBu)4

  14. Block copolymers of poly(l-lactide) and poly(e-caprolactone) or poly(ethylene glycol) prepared by reactive extrusion

    NARCIS (Netherlands)

    Stevels, W.M.; Bernard, A.; van de Witte, P.; van de Witte, P.; Dijkstra, Pieter J.; Feijen, Jan

    1996-01-01

    Blends of poly(L-lactide) (PLLA) and poly(-caprolactone) (PCL) were prepared in a co-rotating twin screw miniextruder (40 rpm, 200°). It was attempted to prepare multiblock copolymers by allowing a controlled number of transesterification reactions. Various cat-alysts (n-Bu3SnOMe, Sn(Oct)2,

  15. MM98.36 Strain Paths in Extrusion

    DEFF Research Database (Denmark)

    Lindegren, Maria; Wiwe, Birgitte; Wanheim, Tarras

    1998-01-01

    The extrusion process has been investigated for different geometries, in order to study the strain path of different material elements during their movements through the plastic zone. This is done by using the FEM code DEFORM and physical simulation with wax togehter with the coefficient method...

  16. The Igwisi Hills extrusive 'kimberlites'

    Science.gov (United States)

    Reid, A. M.; Donaldson, C. H.; Dawson, J. B.; Brown, R. W.; Ridley, W. I.

    1975-01-01

    The petrography and mineral chemistry of volcanic rocks from the Igwisi Hills in Tanzania are discussed. There is considerable evidence to suggest that the Igwisi rocks are extrusive kimberlites: a two-component nature with high P-T minerals in a low P-T matrix; the presence of chrome pyrope, Al enstatite, chrome diopside, chromite and olivine; a highly oxidized, volatile-rich matrix with serpentine, calcite, magnetite, perovskite; high Sr, Zr, and Nb contents; occurrence in a narrow isolated vent within a stable shield area. The Igwisi rocks differ from kimberlite in the lack of magnesian ilmenite, the scarcity of matrix phlogopite, and the overall low alkali content. They apparently contain material from phlogopite-bearing garnet peridotites with a primary mineral assemblage indicative of equilibrium at upper mantle temperatures and pressures. This primary assemblage was brought rapidly to the surface in a gas-charged, carbonate-rich fluid. Rapid upward transport, extrusion, and rapid cooling have tended to prevent reaction between inclusions and the carbonate-rich matrix that might otherwise have yielded a more typical kimberlite.

  17. Aluminum extrusion with a deformable die

    NARCIS (Netherlands)

    Assaad, W.

    2010-01-01

    Aluminum extrusion process is one of metal forming processes. In aluminum extrusion, a work-piece (billet) is pressed through a die with an opening that closely resembles a desired shape of a profile. By this process, long profiles with an enormous variety of cross-sections can be produced to

  18. Effect of feed composition, moisture content and extrusion temperature on extrudate characteristics of yam-corn-rice based snack food.

    Science.gov (United States)

    Seth, Dibyakanta; Badwaik, Laxmikant S; Ganapathy, Vijayalakshmi

    2015-03-01

    Blends of yam, rice and corn flour were processed in a twin-screw extruder. Effects of yam flour (10-40 %), feed moisture content (12-24 %) and extruder barrel temperature (100-140 °C) on the characteristics of the dried extrudates was investigated using a statistical technique response surface methodology (RSM). Radial expansion ratio differed significantly (p ≤ 0.05) with change in all the independent variables. Highest expansion (3.97) was found at lowest moisture content (12 %) and highest barrel temperature (140 °C). Increased yam flour level decreased the expansion ratio significantly. Water absorption index (WAI) increased significantly with increase of all variables. However, water solubility index (WSI) did not change with change in yam flour percent. Hardness of extrudates that varied from 3.86 to 6.94 N was positively correlated with yam flour level and feed moisture content, however it decreased significantly (p ≤ 0.001) with increase of barrel temperature. Yam percent of 15.75 with feed moisture and barrel temperature at 12.00 % and 140 °C respectively gave an optimized product of high desirability (> 0.90) with optimum responses of 3.29 expansion ratio, 5.64 g/g dry solid water absorption index, 30.39 % water solubility index and 3.86 N hardness. The predicted values registered non-significant (p < 0.10) differences from the experimental results. Further study would include the sensory properties enhancement of extruded snacks and little emphasis on the chemistry of interaction between different components.

  19. Sheets of branched poly(lactic acid) obtained by one step reactive extrusion calendering process: Melt rheology analysis

    OpenAIRE

    Cailloux, J.; Santana, O.O.; E. Franco-Urquiza; Bou, J. J.; F. Carrasco; J. Gamez-Perez; M. L. Maspoch

    2013-01-01

    One-step reactive extrusion-calendering process (REX-Calendering) was used in order to obtain sheets of 1mm from two PD,L-LA extrusion grades modified with a styrene-acrylic multifunctional oligomeric agent. In a preliminary internal mixer study, torque versus time was monitored in order to determine chain extender ratios and reaction time. Once all parameters were optimized, reactive extrusion experiments were performed. Independently of the processing method employed, under the same pro...

  20. Extrusion of ECC: Recent Developments and Applications

    DEFF Research Database (Denmark)

    Stang, Henrik; Fredslund-Hansen, Helge; Puclin, Tony;

    2008-01-01

    process. Extrusion of cementitious (fiber reinforced) materials has proven particularly difficult due to the high inter-particle friction combined with the disastrous effect of static zones in the flow pattern, and to the ease of phase migration or separation. In order to deal with these conflicting...... demands on the rheological properties of cementitious particulate materials, various methods have been suggested to dewater the particle suspension during extrusion, however practical extrusion of thin-walled cementitious large-scale elements has not been possible until the discovery of the “dewatering...

  1. EXTRUSION FORMING OF A DOUBLE BASE SOLID ROCKET PROPELLANT BY FINITE ELEMENT METHOD

    Directory of Open Access Journals (Sweden)

    Barış KALAYCIOĞLU

    2007-01-01

    Full Text Available In this study, three dimensional modelling of extrusion forming of a double base solid rocket propellant is performed on Ansys® finite element simulation package. For the purpose of initial model construction and later comparisons with elastoviscoplastik model, the solid propellant is assumed to obey the elastic-plastic material response during the direct extrusion process. Taking into account the contact surface behavior with Coulomb friction and geometric and material nonlinearities, an incremental large large strain solution methodology has been adapted in the simulation. The hydrostatic pressure, stress, strain, and displacement values during extrusion of the solid rocket propellant are obtained from the simulation.

  2. Lubrication in Hot Tube Extrusion of Superalloys and Ti Alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Tubular products made of superalloys and titanium alloys usually work in high temperature environment and applied heavy loading. Hot extrusion is the best technology to form tubular billets with fine microstructures and good mechanical properties. Lubrication is one of the key techniques in hot extrusion, glass lubricants are most suitable for hot extrusion. Lubrication technique in hot extrusion is dealt with in this paper, the lubrication principle of hot tube extrusion is presented. Experiments of glass lubricated backward tube extrusion of titanium alloys and forward tube extrusion of superalloys are also discussed.

  3. Study on Protein Extraction from Caragana Korshinskii by Extrusion%挤压处理柠条提取蛋白质工艺的研究

    Institute of Scientific and Technical Information of China (English)

    张宁; 闫晓光; 高辰; 陈野

    2013-01-01

    Alkaline extracted protein from Caragana Korshinskii which had been extruded. A feasible processing was determined:extrusion processing of raw material→extraction by alkaline solvent→removing impurities→precipitation at isoelectric point→decoloration→freeze-dried. Best conditions for the extrusion of caragana korshinskii powder were:extrusion temperature of 130℃, material moisture content of 30%and the screw rotation speed of 160 r/min; best conditions for alkaline extraction of caragana korshinskii protein were:material liquid ration of 1∶20 (g/mL), extraction time of 60 min, NaOH concentration of 0.1 mol/L and extraction temperature of 90℃;isoelectric point of caragana korshinskii proteins was pI=4.0;for decolorizing, the volume of the ethanol and the quality of raw materials were 1:1 and the decoloration employs elution method. Finally caragana korshinskii protein with good performances was isolated and obtained. Dry product yield of the whole extraction process of the isolation of aragana korshinskii protein was 24.03%, and the protein extraction rate was 65.39%. Through the analysis of nutritional ingredients and electrophoresis analysis , it was considered that the browning of caragana korshinskii proteins was due to the changes of its structure and because the structures of caragana korshinskii proteins could be destroyed during the extraction process.%挤压处理柠条后碱法提取蛋白质,确立一种柠条蛋白提取工艺:挤压处理原料→碱性溶剂提取→去除杂质→等电点沉淀→脱色→冻干。挤压处理的最适条件为:挤压温度为130℃、物料水分含量为30%、螺杆转速为160 r/min,碱提的最适条件为料液比1∶20 g/mL、浸提时间60 min、氢氧化钠浓度0.1 mol/L、浸提温度90℃,等电点pI=4.0,脱色选择1倍体积于原料质量的乙醇用冲洗法脱色。最终得到性状优良的柠条分离蛋白,其干物质得率可达24.03%,蛋白质提取率达65.39%

  4. AFSC/RACE/SAP/Swiney: Primiparous and multiparous Tanner crab egg extrusion, embryo development and hatching

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study compares timing of egg extrusion, embryo development, timing and duration of eclosion, and incubation periods of Kodiak, Alaska primiparous and...

  5. Co-extrusion of piezoelectric ceramic fibres

    OpenAIRE

    Ismael Michen, Marina

    2011-01-01

    The present work successfully developed a methodology for fabricating lead zirconate titanate [PZT] thin solid- and hollow-fibres by the thermoplastic co-extrusion process. The whole process chain, that includes: a) compounding, involving the mixing of ceramic powder with a thermoplastic binder, b) rheological characterizations, c) preform composite fabrication followed by co-extrusion, d) debinding and, finally, e) sintering of the body to near full density, is systematical...

  6. Improvement of mechanical properties and corrosion resistance of biodegradable Mg-Nd-Zn-Zr alloys by double extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaobo, E-mail: xbxbzhang2003@163.com [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China); Wang, Zhangzhong [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China); Yuan, Guangyin [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai, 200240 (China); Xue, Yajun [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China)

    2012-08-01

    Highlights: Black-Right-Pointing-Pointer Microstructure of Mg-Nd-Zn-Zr alloys was refined and homogenized by double extrusion process. Black-Right-Pointing-Pointer The mechanical properties of the alloys were significantly enhanced by double extrusion. Black-Right-Pointing-Pointer The biocorrosion resistance of the alloys was improved by double extrusion. - Abstract: Mg-Nd-Zn-Zr alloy is a novel and promising biodegradable magnesium alloy due to good biocompatibility, desired uniform corrosion mode and outstanding corrosion resistance in simulated body fluid (SBF). However, the corrosion resistance and mechanical properties should be improved to meet the requirement of the biodegradable implants, such as plates, screws and cardiovascular stents. In the present study, double extrusion process was adopted to refine microstructure and improve mechanical properties of Mg-2.25Nd-0.11Zn-0.43Zr and Mg-2.70Nd-0.20Zn-0.41Zr alloys. The corrosion resistance of the alloys after double extrusion was also studied. The results show that the microstructure of the alloys under double extrusion becomes much finer and more homogeneous than those under once extrusion. The yield strength, ultimate tensile strength and elongation of the alloys under double extrusion are over 270 MPa, 300 MPa and 32%, respectively, indicating that outstanding mechanical properties of Mg-Nd-Zn-Zr alloy can be obtained by double extrusion. The results of immersion experiment and electrochemical measurements in SBF show that the corrosion resistance of Alloy 1 and Alloy 2 under double extrusion was increased by 7% and 8% respectively compared with those under just once extrusion.

  7. [New extrusion products in diet therapy of diseases of internal organs].

    Science.gov (United States)

    Meshcheriakova, V A; Plotnikova, O A; Iatsyshina, T A; Sharafetdinov, Kh Kh; Faĭvishevskiĭ, M L; Lisina, T N

    1995-01-01

    Therapeutic effectiveness of 3 new extrusion foods was studied in control conditions of clinic of Institute of nutrition RAMS. The foods were produced by Institute of meat industry RAS on basis of meat resources and wheat brans. The samples of extrusion foods were differed by contents of protein (17-23 g%) and dietary fibers (up to 10%) and used in therapeutic diet for patients with insulin-dependent diabetes mellitus. It was shown that of all three extrusion foods caused decreasing of dyspeptic symptoms during first week of intake and normalisation of intestinal functions without using of laxatives unlike of control group of patients eating standard diabetic diet. It was shown also a decreasing of cholesterol in blood serum of patients received of extrusion foods No 1 and No 3. These samples are recommended for diet therapy and preventive nutrition of patients with metabolic disorders and hypomotoricity of intestinal tract as resources of dietary fibers and protein.

  8. A new flapless technique for crown lengthening after orthodontic extrusion.

    Science.gov (United States)

    Braga, Giovanni; Bocchieri, Anna

    2012-02-01

    Orthodontic extrusion (OE), which is performed in many different clinical situations to move a tooth or its periodontal tissues coronally, is often associated with supracrestal fiberotomy and root planing (OEFRP) or followed by surgical crown lengthening. The OEFRP procedure must be carried out every 2 weeks during the entire extrusive orthodontic phase, and precise control of the technique itself can be quite difficult, especially when this approach is to be performed on a limited portion of the root perimeter in teeth affected by angular defects. The aim of this study was to show a new nonsurgical crown-lengthening technique, performed shortly after the completion of OE, to simultaneously achieve proper hard and soft tissue architecture. Three different illustrative situations (periodontal pocket, root fracture, and root perforation) are described.

  9. Propulsion at low Reynolds number via beam extrusion

    Science.gov (United States)

    Gosselin, Frederick; Neetzow, Paul

    2014-03-01

    We present experimental and theoretical results on the extrusion of a slender beam in a viscous fluid. We are particularly interested in the force necessary to extrude the beam as it buckles with large amplitude due to viscous friction. The problem is inspired by the propulsion of Paramecium via trichocyst extrusion. Self-propulsion in micro-organisms is mostly achieved through the beating of flagella or cilia. However, to avoid a severe aggression, unicellular Paramecium has been observed to extrude trichocysts in the direction of the aggression to burst away. These trichocysts are rod-like organelles which, upon activation, grow to about 40 μm in length in 3 milliseconds before detaching from the animal. The drag force created by these extruding rods pushing against the viscous fluid generates thrust in the opposite direction. We developed an experimental setup to measure the force required to push a steel piano wire into an aquarium filled with corn syrup. This setup offers a near-zero Reynolds number, and allows studying deployments for a range of constant extrusion speeds. The experimental results are reproduced with a numerical model coupling a large amplitude Euler-Bernoulli beam theory with a fluid load model proportional to the local beam velocity. This study was funded in part by the The Natural Sciences and Engineering Research Council of Canada.

  10. DEPOSITION OF TiBN HARD FILMS ON HOT-WORKING-STEEL DIES FOR ALUMINIUM EXTRUSION VIA A DUPLEX PROCESS

    Institute of Scientific and Technical Information of China (English)

    K. MUller

    2001-01-01

    Hot working steels have been used as die materials for hot extrusion of aluminium.Due to tribological interaction at elevated temperature between the die bearing and thesurface of extruded aluminium profiles, not only the surface quality of the extrudedproduct, but also the lifetime of the dies decreases. Deposition of TiBN hard films onthe die bearing could improve the die performance. Treatment should be done in aduplex process process combining a plasma nitriding pretreatment (PN) and a plasmaassisted chemical vapour deposition (PACVD) of TiBN. In this study the influence ofthe process conditions on the properties of the duplex coatings was investigated. Therelationship between structure and mechanical property was researched. For testingthese TiBN hardfilms under elevated temperature conditions and for comparison withother possible coatings special extrusion dies with different coated bearings were used.The extrusion trials were performed on the 8MN-extrusion press at the research anddevelopment center for extrusion, Technical University of Berlin.

  11. Hot melt extrusion versus spray drying: hot melt extrusion degrades albendazole.

    Science.gov (United States)

    Hengsawas Surasarang, Soraya; Keen, Justin M; Huang, Siyuan; Zhang, Feng; McGinity, James W; Williams, Robert O

    2017-05-01

    The purpose of this study was to enhance the dissolution properties of albendazole (ABZ) by the use of amorphous solid dispersions. Phase diagrams of ABZ-polymer binary mixtures generated from Flory-Huggins theory were used to assess miscibility and processability. Forced degradation studies showed that ABZ degraded upon exposure to hydrogen peroxide and 1 N NaOH at 80 °C for 5 min, and the degradants were albendazole sulfoxide (ABZSX), and ABZ impurity A, respectively. ABZ was chemically stable following exposure to 1 N HCl at 80 °C for one hour. Thermal degradation profiles show that ABZ, with and without Kollidon(®) VA 64, degraded at 180 °C and 140 °C, respectively, which indicated that ABZ could likely be processed by thermal processing. Following hot melt extrusion, ABZ degraded up to 97.4%, while the amorphous ABZ solid dispersion was successfully prepared by spray drying. Spray-dried ABZ formulations using various types of acids (methanesulfonic acid, sulfuric acid and hydrochloric acid) and polymers (Kollidon(®) VA 64, Soluplus(®) and Eudragit(®) E PO) were studied. The spray-dried ABZ with methanesulfonic acid and Kollidon(®) VA 64 substantially improved non-sink dissolution in acidic media as compared to bulk ABZ (8-fold), physical mixture of ABZ:Kollidon(®) VA 64 (5.6-fold) and ABZ mesylate salt (1.6-fold). No degradation was observed in the spray-dried product for up to six months and less than 5% after one-year storage. In conclusion, amorphous ABZ solid dispersions in combination with an acid and polymer can be prepared by spray drying to enhance dissolution and shelf-stability, whereas those made by melt extrusion are degraded.

  12. Viscoplastic flow in an extrusion damper

    CERN Document Server

    Syrakos, Alexandros; Georgiou, Georgios C; Tsamopoulos, John

    2016-01-01

    Numerical simulations of the flow in an extrusion damper are performed using a finite volume method. The damper is assumed to consist of a shaft, with or without a spherical bulge, oscillating axially in a containing cylinder filled with a viscoplastic material of Bingham type. The response of the damper to a forced sinusoidal displacement is studied. In the bulgeless case the configuration is the annular analogue of the well-known lid-driven cavity problem, but with a sinusoidal rather than constant lid velocity. Navier slip is applied to the shaft surface in order to bound the reaction force to finite values. Starting from a base case, several problem parameters are varied in turn in order to study the effects of viscoplasticity, slip, damper geometry and oscillation frequency to the damper response. The results show that, compared to Newtonian flow, viscoplasticity causes the damper force to be less sensitive to the shaft velocity; this is often a desirable damper property. The bulge increases the required...

  13. Formation of chromosomal domains in interphase by loop extrusion

    Science.gov (United States)

    Fudenberg, Geoffrey

    While genomes are often considered as one-dimensional sequences, interphase chromosomes are organized in three dimensions with an essential role for regulating gene expression. Recent studies have shown that Topologically Associating Domains (TADs) are fundamental structural and functional building blocks of human interphase chromosomes. Despite observations that architectural proteins, including CTCF, demarcate and maintain the borders of TADs, the mechanisms underlying TAD formation remain unknown. Here we propose that loop extrusion underlies the formation TADs. In this process, cis-acting loop-extruding factors, likely cohesins, form progressively larger loops, but stall at TAD boundaries due to interactions with boundary proteins, including CTCF. This process dynamically forms loops of various sizes within but not between TADs. Using polymer simulations, we find that loop extrusion can produce TADs as determined by our analyses of the highest-resolution experimental data. Moreover, we find that loop extrusion can explain many diverse experimental observations, including: the preferential orientation of CTCF motifs and enrichments of architectural proteins at TAD boundaries; TAD boundary deletion experiments; and experiments with knockdown or depletion of CTCF, cohesin, and cohesin-loading factors. Together, the emerging picture from our work is that TADs are formed by rapidly associating, growing, and dissociating loops, presenting a clear framework for understanding interphase chromosomal organization.

  14. Weld formation during material extrusion additive manufacturing.

    Science.gov (United States)

    Seppala, Jonathan E; Hoon Han, Seung; Hillgartner, Kaitlyn E; Davis, Chelsea S; Migler, Kalman B

    2017-08-18

    Material extrusion (ME) is a layer-by-layer additive manufacturing process that is now used in personal and commercial production where prototyping and customization are required. However, parts produced from ME frequently exhibit poor mechanical performance relative to those from traditional means; moreover, fundamental knowledge of the factors leading to development of inter-layer strength in this highly non-isothermal process is limited. In this work, we seek to understand the development of inter-layer weld strength from the perspective of polymer interdiffusion under conditions of rapidly changing mobility. Our framework centers around three interrelated components: in situ thermal measurements (via infrared imaging), temperature dependent molecular processes (via rheology), and mechanical testing (via mode III fracture). We develop the concept of an equivalent isothermal weld time and test its relationship to fracture energy. For the printing conditions studied the equivalent isothermal weld time for Tref = 230 °C ranged from 0.1 ms to 100 ms. The results of these analysis provide a basis for optimizing inter-layer strength, the limitations of the ME process, and guide development of new materials.

  15. Mitotic chromosome compaction via active loop extrusion

    Science.gov (United States)

    Goloborodko, Anton; Imakaev, Maxim; Marko, John; Mirny, Leonid; MIT-Northwestern Team

    During cell division, two copies of each chromosome are segregated from each other and compacted more than hundred-fold into the canonical X-shaped structures. According to earlier microscopic observations and the recent Hi-C study, chromosomes are compacted into arrays of consecutive loops of ~100 kilobases. Mechanisms that lead to formation of such loop arrays are largely unknown. Here we propose that, during cell division, chromosomes can be compacted by enzymes that extrude loops on chromatin fibers. First, we use computer simulations and analytical modeling to show that a system of loop-extruding enzymes on a chromatin fiber self-organizes into an array of consecutive dynamic loops. Second, we model the process of loop extrusion in 3D and show that, coupled with the topo II strand-passing activity, it leads to robust compaction and segregation of sister chromatids. This mechanism of chromosomal condensation and segregation does not require additional proteins or specific DNA markup and is robust against variations in the number and properties of such loop extruding enzymes. Work at NU was supported by the NSF through Grants DMR-1206868 and MCB-1022117, and by the NIH through Grants GM105847 and CA193419. Work at MIT was supported by the NIH through Grants GM114190 R01HG003143.

  16. IMPORTANT DEGRADATIONS IN POLYETHYLENE TERAPHTALATE EXTRUSION PROCESS

    Directory of Open Access Journals (Sweden)

    Şule ALTUN

    2003-01-01

    Full Text Available Polyethylene terephthalate (PET is one of the most used thermo-plastic polymers. The total consumption of PET has been about 30 million tons in the year 2000. Polyester fibers constitute about 60 % of total synthetic fibers consumption. During extrusion, PET polymer is faced to thermal, thermo-oxidative and hydrolytic degradation, which result in severe reduction in its molecular weight, thereby adversely affecting its subsequent melt processability. Therefore, it is essential to understand degradation processes of PET during melt extrusion.

  17. Effects of extrusion processing on nutrients in dry pet food

    NARCIS (Netherlands)

    Tran, Q.D.; Hendriks, W.H.; Poel, van der A.F.B.

    2008-01-01

    Extrusion cooking is commonly used to produce dry pet foods. As a process involving heat treatment, extrusion cooking can have both beneficial and detrimental effects on the nutritional quality of the product. Desirable effects of extrusion comprise increase in palatability, destruction of

  18. Extrusion instability in an aramid fibre spinning process

    NARCIS (Netherlands)

    Drost, S.

    2015-01-01

    The efficiency of polymer extrusion processes can be severely limited by the occurrence of viscoelastic extrusion instabilities. In a para-aramid fibre spinning process, for example, a μm-scale extrusion instability is responsible for the waste of tons of polymer per year. At present, a considerab

  19. Numerical Simulation Study of Ni-based Pipe in Hot Extrusion for Glass Iubrication Mechanism%镍基管材热挤压中玻璃润滑机理的数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    孙海伟; 范永革; 易勇

    2011-01-01

    模拟摩擦效应对镍基合金管材热挤压的不良影响,着重从挤压力方面讨论了挤压过程的可行性.研究表明:钢坯两侧润滑系数f在0.02~0.03,玻璃垫处在0 01附近,金属匀速流动,径向应力应变分布均匀;当f>0.05时,会造成挤压曲线震荡,不利于热挤压的进行.%The bad influence of friction on hot extrusion of Ni-based alloy pipe was simulated. The feasibility of extrusion process was seriously discussed from extrusion pressure aspects. The results show that when the lubrication coefficient/ is between 0.02 and 0.03 at billet's both sides and is near 0.01 at glass pad, the metal flows uniformly and the radial stress and strain distribute uniformly; when the / is bigger than 0.05, the extrusion curve shocks, and it is not conducive to carry on hot extrusion.

  20. Effects of extrusion conditions on the extrusion responses and the quality of brown rice pasta.

    Science.gov (United States)

    Wang, Li; Duan, Wei; Zhou, Sumei; Qian, Haifeng; Zhang, Hui; Qi, Xiguang

    2016-08-01

    This research investigated the effects of extrusion temperature and screw speed on the extrusion system parameters and the qualities of brown rice pasta. The die pressure and motor torque value reached a maximum at 90°C but decreased when the screw speed increased from 80 to 120rpm. The extrusion temperature and screw speed also significantly affected the cooking quality and textural properties of brown rice pasta. The pasta produced at an extrusion temperature of 120°C and screw speed of 120rpm had the best quality with a cooking loss, hardness and adhesiveness of 6.7%, 2387.2g and -7.0g⋅s, respectively, similar to those of pasta made from gluten-free flour. The results indicated that brown rice can be used to produce gluten-free pasta with improved nutrition.

  1. Hydrodynamic modelling of hydrostatic magnesium extrusion

    NARCIS (Netherlands)

    Moodij, E.; Rooij, de M.B.; Schipper, D.J.

    2006-01-01

    Wilson’s hydrodynamic model of the hydrostatic extrusion process is extended to meet the geometry found on residual billets. The transition from inlet to work zone of the process is not considered sharp as in the model of Wilson but as a rounded edge, modelled by a parabolic function. It is shown th

  2. Friction phenomena in hydrostatic extrusion of magnesium

    NARCIS (Netherlands)

    Moodij, Ellen

    2014-01-01

    When magnesium is hydrostatically extruded an inconsistent and sometimes bad surface quality is encountered. In hydrostatic extrusion the billet is surrounded by a lubricant, usually castor oil. The required pressure to deform the material is applied onto this lubricant and not directly to the bill

  3. Formation of Chromosomal Domains by Loop Extrusion

    Directory of Open Access Journals (Sweden)

    Geoffrey Fudenberg

    2016-05-01

    Full Text Available Topologically associating domains (TADs are fundamental structural and functional building blocks of human interphase chromosomes, yet the mechanisms of TAD formation remain unclear. Here, we propose that loop extrusion underlies TAD formation. In this process, cis-acting loop-extruding factors, likely cohesins, form progressively larger loops but stall at TAD boundaries due to interactions with boundary proteins, including CTCF. Using polymer simulations, we show that this model produces TADs and finer-scale features of Hi-C data. Each TAD emerges from multiple loops dynamically formed through extrusion, contrary to typical illustrations of single static loops. Loop extrusion both explains diverse experimental observations—including the preferential orientation of CTCF motifs, enrichments of architectural proteins at TAD boundaries, and boundary deletion experiments—and makes specific predictions for the depletion of CTCF versus cohesin. Finally, loop extrusion has potentially far-ranging consequences for processes such as enhancer-promoter interactions, orientation-specific chromosomal looping, and compaction of mitotic chromosomes.

  4. 75 FR 80527 - Aluminum Extrusions From China

    Science.gov (United States)

    2010-12-22

    ... Republic of China: Postponement of Final Determination of Sales at Less Than Fair Value, 75 FR 73041... Sales at Less Than Fair Value, and Preliminary Determination of Targeted Dumping, 75 FR 69403, November... Affirmative Countervailing Duty Determination, 75 FR 54302, September 7, 2010, and Aluminum Extrusions...

  5. Energy aspects in food extrusion-cooking

    NARCIS (Netherlands)

    Janssen, L.P.B.M.; Moscicki, L.; Mitrus, M.

    2002-01-01

    Theoretical and practical energy balance considerations in food extrusion-cooking are presented in the paper. Based on the literature review as well as on own measurement results, the baro-thermal treatment of different vegetable raw materials is discussed together with the engineering aspects of th

  6. Limits of Lubrication in Backward Can Extrusion

    DEFF Research Database (Denmark)

    Bennani, B; Bay, Niels

    1996-01-01

    The increasing demand in industry to produce cans at low reduction by the backward extrusion process involves better understanding of this process. To analyse the process, numerical simulations by the finite-element method and experimental simulations by physical modelling using wax as a model...

  7. Robo-Enabled Tumor Cell Extrusion.

    Science.gov (United States)

    Richardson, Helena E; Portela, Marta

    2016-12-19

    How aberrant cells are removed from a tissue to prevent tumor formation is a key question in cancer biology. Reporting in this issue of Developmental Cell, Vaughen and Igaki (2016) show that a pathway with an important role in neural guidance also directs extrusion of tumor cells from epithelial tissues.

  8. Root resorption after orthodontic intrusion and extrusion:.

    NARCIS (Netherlands)

    Han, G.; Huang, S.; Hoff, J.W. Von den; Zeng, X.; Kuijpers-Jagtman, A.M.

    2005-01-01

    The aim of this investigation was to compare root resorption in the same individual after application of continuous intrusive and extrusive forces. In nine patients (mean age 15.3 years), the maxillary first premolars were randomly intruded or extruded with a continuous force of 100 cN for eight wee

  9. Optimization of mechanical and damping properties of Mg–0.6Zr alloy by different extrusion processing

    OpenAIRE

    Wang, Jingfeng; Wu, Zhongshan; Gao, Shan; Lu, Ruopeng; Qin, Dezhao; Yang,Wenxiang; Pan, Fusheng

    2015-01-01

    In this study, the optimization of mechanical and damping capacities of Mg-0.6 wt.% Zr alloys by controlling the recrystallized (DRXed) grain size under varying extrusion processing parameters including extrusion temperature T and strain rate ε˙ was investigated. The relationship between the DRXed grain size and damping properties of the studied alloy was also discussed. The DRXed grain size of the as-extruded Mg–Zr alloys decreased as the extrusion temperature T decreased and the strain rate...

  10. FEM Analysis of Force Parameters During Hot Extrusion Expanding and Reducing Tube Process

    Institute of Scientific and Technical Information of China (English)

    WANG Fenghui; JIAO Anyuan; LI Haidong; GAO Xingqi; YANG Siqiong

    2006-01-01

    In this paper, based on the plastic forming large deformation theory and thermodynamic elastic-plastic FEM, the process of expanding and reducing tube was analyzed by using nonlinear finite element software MARC. The coupled thermal-mechanical models for the thermal-extrusion tube process were established, and the dynamic simulation to them was carried out. By the study on 3D deformation regulation of the thermal-extrusion tube, the distribution of stress,strain and the curves between the force of extrusion and the distance were obtained. As a result, with only a small quantity of necessary experiments, the select of the schemes and parameters can conveniently be performed in the computers. So, not only large numbers of experiments can be avoided, but also trial-manufacture period is consumedly shortened and some costs may be saved. In addition, in order to validate our numerical calculation, an experiment of the tube made of 20 steel is presented in this paper. Good agreement is shown between measured and predicted results of the theoretical analysis model. The study provides a scientific basis for parametric optimizations of the thermal extrusion expanding and reducing tube production equipment. At the same time, the method used in the present paper has important referential value for studying the similar thermal extrusion parts.

  11. Replication of micro-sized pillars in polypropylene using the extrusion coating process

    DEFF Research Database (Denmark)

    Okulova, Nastasia; Johansen, Peter; Christensen, Lars

    2017-01-01

    A recent advancement in nano-pattern replication using roll-to-roll extrusion coating (R2R-EC) shows potential for many biomimetic applications. For further development of the technique a study of the micro-replication regime is carried out. In this study a full and partial replication in polypro......A recent advancement in nano-pattern replication using roll-to-roll extrusion coating (R2R-EC) shows potential for many biomimetic applications. For further development of the technique a study of the micro-replication regime is carried out. In this study a full and partial replication...... in polypropylene (PP) of micro-sized pillars has been demonstrated using the extrusion coating process. The replication fidelity of the pillars is investigated in a systematic variation of different process parameters: the line-speed of the rolls, the extruder output, the cooling roll temperature and the pressure...

  12. Comparison of Murine Cervicovaginal Infection by Chlamydial Strains: Identification of Extrusions Shed In vivo

    Science.gov (United States)

    Shaw, Jennifer H.; Behar, Amanda R.; Snider, Timothy A.; Allen, Noah A.; Lutter, Erika I.

    2017-01-01

    Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections (STIs) and preventable blindness. Untreated, asymptomatic infection as well as frequent re-infection are common and may drive pelvic inflammatory disease, ectopic pregnancy, and infertility. In vivo models of chlamydial infection continue to be instrumental in progress toward a vaccine and further elucidating the pathogenesis of this intracellular bacterium, however significant gaps in our understanding remain. Chlamydial host cell exit occurs via two mechanisms, lysis and extrusion, although the latter has yet to be reported in vivo and its biological role is unclear. The objective of this study was to investigate whether chlamydial extrusions are shed in vivo following infection with multiple strains of Chlamydia. We utilized an established C3H/HeJ murine cervicovaginal infection model with C. trachomatis serovars D and L2 and the Chlamydia muridarum strain MoPn to monitor the (i) time course of infection and mode of host cell exit, (ii) mucosal and systemic immune response to infection, and (iii) gross and histopathology following clearance of active infection. The key finding herein is the first identification of chlamydial extrusions shed from host cells in an in vivo model. Extrusions, a recently appreciated mode of host cell exit and potential means of dissemination, had been previously observed solely in vitro. The results of this study demonstrate that chlamydial extrusions exist in vivo and thus warrant further investigation to determine their role in chlamydial pathogenesis. PMID:28217555

  13. The Influence of Extrusion Ratio on W-40 % Cu Alloy Produced by Powder Canning Hot Extrusion%挤压比对粉末包套热挤压致密W-40%Cu合金的影响

    Institute of Scientific and Technical Information of China (English)

    李达人; 蔡一湘; 刘祖岩; 王尔德

    2012-01-01

    采用不同挤压比对W-40%Cu混合粉末进行粉末包套热挤压,获得了W--40%Cu合金.研究了模具总挤压比λ对热挤压坯料致密化以及组织性能的影响.结果表明,随着挤压比的增加,热挤压坯料的相对密度也增加,同时电导率和硬度值也随之提高.由于含铜量比较高(质量分数为40%),即便在挤压比为25时,挤压坯内部W相也不发生变形,主要是铜相产生变形.进一步将模具总挤压比λ细分为不考虑体积变形的坯料总挤压比α,除去体积变形因素的坯料塑性挤压比β以及包套挤压比γ三种实际挤压比,分析了不同挤压比对热挤压致密化过程的影响.%W-40 wt.%Cu alloys with different extrusion ratio have been obtained by powder canning hot extrusion. The experimental results show that, the relative density, specific conductance and hardness of the billets increase with the adding extrusion ratio. There is no shape change of W phase after powder canning hot extrusion even if the extrusion ratio is up to 25 due to high content of Cu phase (40 wt.%). The deformation mainly occurs in Cu phase. The total extrusion ratio (λ) is divided into three kinds of actual extrusion ratio: the extrusion ratio of billet (α) without considering the volumetric deformation; the plastic extrusion ratio (β) excluding the influence of volumetric deformation; the extrusion ratio of can (γ). This article studies the influence of these three kinds of actual extrusion ratio on the densification of W-40 wt.% Cu alloy by powder canning hot extrusion.

  14. Photosynthetic pigments, cell extrusion and relative leaf water content of the castor bean under silicon and salinity

    National Research Council Canada - National Science Library

    Ferraz, Rener L. de S; Magalhães, Ivomberg D; Beltrão, Napoleão E. de M; Melo, Alberto S. de; Brito Neto, Jósé F. de; Rocha, Maria do S

    2015-01-01

    .... Thus, this study aimed to evaluate the contents of photosynthetic pigments, cell membrane extrusion and the relative water content in the leaves of the castor bean cultivar 'BRS Energia' under...

  15. Smooth Particle Hydrodynamics Simulation of Micro-Cup-Extrusion Using a Graphit-ic Coating

    Directory of Open Access Journals (Sweden)

    Li Shi-Cheng

    2014-01-01

    Full Text Available Microextrusion is becoming increasingly important for the manufacturing of microcomponents. However, this reduction in scale to a microlevel means that the influence of friction and the need for suitable lubrication are greatly increased. This study therefore looks at the use of a low-friction and highly wear resistant Graphit-ic coating on the mold-forming section of a microextrusion mold, this coating being applied by a closed-field unbalanced magnetron sputter ion plating technique. A microcup of CuZn33 brass alloy was then extruded, with a wall thickness of 0.45 mm, outside diameter of 2.9 mm, and an internal diameter of 2 mm. The experimental results in which extrusion uses the mold coating with Graphit-ic film are compared against the experimental results in which extrusion uses the mold uncoating with Graphit-ic film. This showed that the load was decreased a lot and the self-lubricating solid coating facilitates a smooth extrusion process. As the extrusion rate was quite high, smoothed particle hydrodynamics method simulations of the extrusion process were conducted, these being then compared with the experimental results. These result showed that the SPH simulation can be applied to show the deformation of materials and predict the load trend.

  16. Effect of die shape on the metal flow pattern during direct extrusion process

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, N.; Solomon, I.

    2010-07-01

    The geometric shape of the tools is the main factor by which an optimum technological process can be developed. In the case of extrusion process the strain distribution and other important variables that influence material structure, such as hydrostatic stress, are strongly dependent on the geometry of the die. Careful design of the extrusion die profile can therefore control the product structure and can be used to minimise the amount of inhomogeneity imparted into the product. A possibility to minimise the amount of product inhomogeneity is the using of a flat die with a fillet radius in front to the bearing surface with leads to a minimum dead zone and consequently to a minimum friction at billet-container interface. In the case of aluminium alloy type 2024, for an extrusion ratio of R=8.5, good results were obtained with a fillet radius of 3.0 mm. The experimental data have been used for the finite element numerical simulation of the extrusion process. The data obtained by numerical simulation with FORGE2 programme confirm the theoretical and experimental outcomes. The aim of this paper is to study the influence of such flat die on the material flow during direct extrusion process and consequently on extruded product microstructure and mechanical properties. (Author).

  17. Die Radius Affecting Sheet Metal Extrusion Quality for Fine Blanking Process

    Directory of Open Access Journals (Sweden)

    Chatkaew Suriyapha

    2010-01-01

    Full Text Available Problem statement: Sheet metal extrusion is a process in which the punch penetrates one surface of the sheet metal material to cause it to extrude and flow toward the outlet of the die. Therefore, the process can invent different thickness of sheet metal work piece. From these advantages on the sheet metal extrusion, nowadays, it is generally used in many manufacturing of industrial elements fields. The Sheet Metal Extrusions in Fine Blanking (SME-FB advantages, over a conventional extrusion, are possible due to a blank holder force, a counterpunch force and a large die radius. However, the selection on those parameter values affects on the material flow and the surface quality on the extrusion parts also. Namely, it causes the crack surface and shrinkage failure which are the general problems in the SME-FB. Approach: Objective of this research was to study the effect of die radius on the SME-FB surface which investigated the formation of the failure defection with respect to the several die radiuses by using the Finite Element Method (FEM. Results: From the results, it indicated that applying the small die radius caused the material flow difficult resulting in the decreasing of smooth surface. Vice versa, in the case of large die radius, the material flow easy is resulting in the increasing of smooth surface. Conclusion: The FEM simulation results of a larger die radius will cause the residual stress at work piece.

  18. Optimization of pneumatic sheet extrusion of whole wheat flour poory dough using response surface methodology.

    Science.gov (United States)

    Murthy, K Venkatesh; Sudha, M L; Ravi, R; Raghavarao, K S M S

    2015-07-01

    Pneumatic extrusion of whole wheat flour dough is a challenge in the preparation of Poory. In the present study, the pneumatic extrusion process variables (pneumatic pressure, rate of extrusion) and quality of deep fried product (oil uptake, frying time, puffed height) was evaluated to get Poory of maximum overall sensory quality, minimum shear and minimum oil uptake. These parameters depend on the moisture content of wheat dough. Response surface methodology was demonstrated to be an efficient tool for the optimization of process parameters of pneumatic extrusion. The results indicated that extrusion pressure ranging from 3 ~ 6 × 10(5) Pa for the whole wheat flour dough with added moisture of 56 ~ 60 % was found to give a uniform rate of extruded sheet. It was observed that submerged frying time for the extruded dough sheet was in the range of 35 ~ 40 s, with the temperature of the vegetable oil to be in the range of 180 ~ 185 °C. Oil uptake during frying was about 12 ± 1 % and the textural shear force was found to be 9.9 N with an overall sensory score of 7.2 ± 0.5 on nine point scale. The experimental errors for all attributes were non-significant (p > 0.05) and thus optimum variables predicted by the model are found suitable.

  19. Effect of extrusion rate on morphology of Kaolin/PolyEtherSulfone (PESf) membrane precursor

    Science.gov (United States)

    Misaran, M. S.; Sarbatly, R.; Bono, A.; Rahman, M. M.

    2016-11-01

    This study aims to investigate the influence of apparent viscosity induced by spinneret geometry and extrusion rate on morphology of Kaolin/PESf hollow fiber membranes. Different extrusion rates at two different rheology properties were introduced on a straight and conical spinneret resulting in various shear rates. The hollow fiber membrane precursors were spun using the wet spinning method to decouple the effect of shear and elongation stress due to gravity stretched drawing. The morphology of the spun hollow fiber was observed under Scanning Electron Microscope (SEM) and the overall porosity were measured using mercury intrusion porosimeter. Shear rate and apparent viscosity at the tip of the spinneret annulus were simulated using a computational fluid dynamics package; solidworks floworks. Simulation data shows that extrusion rate increment increases the shear rate at the spinneret wall which in turn reduce the apparent viscosity; consistent with a non Newtonian shear thinning fluid behavior. Thus, the outer finger-like region grows as the shear rate increases. Also, overall porosity of hollow fiber membrane decreases with extrusion rate increment which is caused by better molecular orientation; resulting in denser hollow fiber membrane. Thin outer finger-like region is achieved at low shear experience of 109.55 s-1 via a straight spinneret. Increasing the extrusion rate; thus shear rate will cause outer finger-like region growth which is not desirable in a separation process.

  20. A process planning system for cold extrusion

    Directory of Open Access Journals (Sweden)

    SANTOSH KUMAR,

    2010-12-01

    Full Text Available A Process Planning system ProEx-Cold is developed for extrusion shapes to eliminate the tedious and expensive procedure of trial and correction of a proper die and the process. The system has three modules as: feature recognition, upper bound analysis and 3D graphics generation & display using OpenGL application engine. The input parameters to the proposed CAPP system includes: die type, billet TYPE & material, geometrical details of the product, ram speed,reduction, friction condition and billet condition etc. to influence parameters like production rate, extrusion ram pressure etc. C-programming, OpenGL graphics and Visual C++ editor has been used to implement ProEx-Cold.

  1. The extrusion properties of potato granules

    OpenAIRE

    Kooi, Eng Teong

    1982-01-01

    Potato granules from different sources were found, on extrusion, to produce potato snacks of variable quality. In some instances strip formation was unsatisfactory, in other instances blistering of the snack occurred on frying. In total, about 20-25 batches of potato granules were examined and classified in relation to these two phenomena. The amylose/amylopectin ratios of these samples of potato granules were determined by the semi-micro potentiometric iodine titration technique, but it was ...

  2. Characterisation of the wall-slip during extrusion of heavy-clay products

    Science.gov (United States)

    Kocserha, I.; Gömze, A. L.; Kulkov, S.; Kalatur, E.; Buyakova, S. P.; Géber, R.; Buzimov, A. Y.

    2017-01-01

    During extrusion through the extrusion die, heavy-clay compounds are usually show plug flow with extensive slip at the wall of the die. In this study, the viscosity and the thickness of the slip layer were investigated. For the examination a brick-clay from Malyi (Hungary) deposit was applied as a raw material. The clay was characterised by XRPD, BET, SEM and granulometry. As the slip layer consists of suspension of the fine clay fraction so the clay minerals content of the clay (dwater content was measured by means of rotational viscosimeter. The thickness of the slip layer was calculated from the measured viscosity and other data obtained from an earlier study with capillary rheometer. The calculated thickness value showed a tendency to reach a limit value by increasing the extrusion speed.

  3. Dynamic-tensile-extrusion response of fluoropolymers

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Eric N [Los Alamos National Laboratory; Trujillo, Carl P [Los Alamos National Laboratory; Gray, George T [Los Alamos National Laboratory

    2009-01-01

    The current work applies the recently developed Dynamic-Tensile-Extrusion (Dyn-Ten-Ext) technique to polytetrafluoroethylene (PTFE) and polychlorotrifluoroethylene (PCTFE). Similar to the Taylor Impact Rod, Dynamic-Tensile-Extrusion is a strongly integrated test, probing a wide range of strain rates and stress states. However, the stress state is primarily tensile enabling investigation of dynamic tensile failure modes. Here we investigate the influence of this propensity to neck or not between PCTFE and PTFE on their response under dynamic tensile extrusion loading. The results of the Dyn-Ten-Ext technique are compared with two classic techniques. Both polymers have been investigated using Tensile Split Hopkinson Pressure Bar. The quasistatic and dynamic responses of both fluoro-polymers have been extensively characterized. The two polymers exhibit significantly different failure behavior under tensile loading at moderate strain rates. Polytetrafluoroethylene resists formation of a neck and exhibits significant strain hardening. Independent of temperature or strain rate, PTFE sustains true strains to failure of approximately 1.5. Polychlorotrifluoroethylene, on the other hand, consistently necks at true strains of approximately 0.05.

  4. Loaded versus unloaded magnetic resonance imaging (MRI of the knee: Effect on meniscus extrusion in healthy volunteers and patients with osteoarthritis

    Directory of Open Access Journals (Sweden)

    Rina Patel

    2016-01-01

    Conclusion: Our study demonstrated that medial meniscal extrusion significantly increased during loading, specifically in those low KL scores (0 and 1 and in KL score of 3. Loaded MRI may more accurately determine the extent of medial meniscal extrusion in particular in those with no to minimal OA.

  5. Study The Properties and Weight Loss Degradation of The Blend LDPE/Cellulose in Soil Environment

    Directory of Open Access Journals (Sweden)

    Zuhair Jabbar Abdul Ameer

    2017-05-01

    Full Text Available Wider applications of polyethylene (PE in packaging and agriculture have raised serious issue of waste disposal and pollution. Therefore, it is necessary to raise its biodegradability by additives.In this study, we will add cellulose to low density polyethylene to prepare polymer blend have ability to degradation in soil environment.The samples were prepared by using twin screw extruder.LDPE and CELL have been mixing with different weight proportions, and studied their properties in order to determine its compliance with the required specifications to be able to be used biodegradable polymers. To improve the viability of decomposition PEG has been added to the resulting blend. Several tests were applied to identify those properties such as tensile,hardness, density and creep test. FTIR, digital microscope and SEM test acheved in order to determine the miscibility and blend morphology befor and after degradation.The results show that,the blend weight loss increase with increasing CELL percent.

  6. Large scale production of vesicles by hollow fiber extrusion: a novel method for generating polymersome encapsulated hemoglobin dispersions.

    Science.gov (United States)

    Rameez, Shahid; Bamba, Ibrahim; Palmer, Andre F

    2010-04-06

    Vesicles, which include both liposomes and polymersomes (polymer vesicles), are being developed as therapeutic drug carriers. In this study, we present a fully scalable low pressure extrusion methodology for preparing vesicles. Vesicles were generated by continuous extrusion through a 200 nm pore diameter hollow fiber (HF) membrane. The first half of this study describes a method for generating empty polymersomes composed of different molecular weight amphiphilic poly(butadiene-b-ethylene oxide) (PBD-b-PEO) diblock copolymers on a large scale (50-100 mL) using a HF membrane. Monodisperse empty polymersomes were formed with particle diameters slightly less than 200 nm, which were close to the rated 200 nm pore size of the HF membrane. The second half of this study describes the successful encapsulation of hemoglobin (Hb) inside the aqueous core of polymersomes using the HF extrusion methodology. We demonstrate that polymersome encapsulated hemoglobin (PEH) particles formed by this technique had similar oxygen affinity, cooperativity coefficient, and methemoglobin (metHb) level compared to PEH particles formed by the 1 mL volume small scale manual extrusion method. Most notably, Hb encapsulation inside the polymer vesicles formed by the HF extrusion method increased 2-fold compared to the manual extrusion method. This work is important, since it will enable facile scale-up of homogeneous vesicle dispersions that are typically required for preclinical and clinical studies as well as industrial use.

  7. Spectrophotometric determination of irrigant extrusion using passive ultrasonic irrigation, EndoActivator, or syringe irrigation.

    Science.gov (United States)

    Rodríguez-Figueroa, Carolina; McClanahan, Scott B; Bowles, Walter R

    2014-10-01

    Sodium hypochlorite (NaOCl) irrigation is critical to endodontic success, and several new methods have been developed to improve irrigation efficacy (eg, passive ultrasonic irrigation [PUI] and EndoActivator [EA]). Using a novel spectrophotometric method, this study evaluated NaOCl irrigant extrusion during canal irrigation. One hundred fourteen single-rooted extracted teeth were decoronated to leave 15 mm of the root length for each tooth. Cleaning and shaping of the teeth were completed using standardized hand and rotary instrumentation to an apical file size #40/0.04 taper. Roots were sealed (not apex), and 54 straight roots (n = 18/group) and 60 curved roots (>20° curvature, n = 20/group) were included. Teeth were irrigated with 5.25% NaOCl by 1 of 3 methods: passive irrigation with needle, PUI, or EA irrigation. Extrusion of NaOCl was evaluated using a pH indicator and a spectrophotometer. Standard curves were prepared with known amounts of irrigant to quantify amounts in unknown samples. Irrigant extrusion was minimal with all methods, with most teeth showing no NaOCl extrusion in straight or curved roots. Minor NaOCl extrusion (1-3 μL) in straight roots or curved roots occurred in 10%-11% of teeth in all 3 irrigant methods. Two teeth in both the syringe irrigation and the EA group extruded 3-10 μL of NaOCl. The spectrophotometric method used in this study proved to be very sensitive while providing quantification of the irrigant levels extruded. Using the PUI or EA tip to within 1 mm of the working length appears to be fairly safe, but apical anatomy can vary in teeth to allow extrusion of irrigant. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  8. Evolution Of Precipitate Morphology During Extrusion In Mg ZK60A Alloy

    Directory of Open Access Journals (Sweden)

    Park J.

    2015-06-01

    Full Text Available In this study, a continuously casted ZK60A magnesium alloy (Mg-Zn-Zr was extruded in two different extrusion ratios, 6:1 and 10:1. The evolution of precipitates was investigated on the two extruded materials and compared with that of as-casted material. The microstructural analysis was performed by electron backscatter diffraction and transmission electron microscopy, and the compositional information was obtained using energy-dispersive X-ray spectroscopy. Several distinct morphologies of precipitates were observed, such as dot, rod, and disk shaped. The formation mechanisms of those precipitates were discussed with respect to the heat and strain during the extrusion process.

  9. Key technologies of "zero die trial" design system for aluminum profile extrusion

    Institute of Scientific and Technical Information of China (English)

    罗超; 李大永; 彭颖红; 左铁镛

    2004-01-01

    Aluminum alloy profile parts are widely used in the fields of aviation, equipment, automobile and ornamental industries. The construction method for "zero die trial" intelligent design system of aluminum extrusion die was studied based on KBE idea. An object-oriented knowledge language AEKL(Aluminum Extrusion Knowledge Language) was developed to construct intelligent knowledge model with three methods, frame, parameters and rules. On the aspect of knowledge reasoning, case-based reasoning was employed in addition to traditional rule-based reasoning method. API provided by CAD platform was used in geometry disposal. Finally, the corresponding prototyping system was established and an design example was shown.

  10. Influence of Mg Content on Deformability of AlMg Alloys during Extrusion

    Directory of Open Access Journals (Sweden)

    Leśniak D.

    2016-03-01

    Full Text Available In this study the research on deformability of AlMg alloys with high Mg contents in extrusion was carried out. The different shapes from AlMg alloys containing 3.5%, 4.5% and 5.5% of Mg were extruded on 500 T semi-industrial press by using one-hole and multi-hole flat dies. The extrudates surface quality was under investigations in relation with the temperature-speed parameters of the extrusion process. The metal exit speed was estimated depending on the extrudates shape, wall thickness and Mg content. The alloy’s border solidus and liquidus temperatures were also determined.

  11. Zr Extrusion – Direct Input for Models & Validation

    Energy Technology Data Exchange (ETDEWEB)

    Cerreta, Ellen Kathleen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-07

    As we examine differences in the high strain rate, high strain tensile response of high purity, highly textured Zr as a function of loading direction, temperature and extrusion velocity with primarily post mortem characterization techniques, we have also developed a technique for characterizing the in-situ extrusion process. This particular measurement is useful for partitioning energy of the system during the extrusion process: friction, kinetic energy, and temperature

  12. Hydrodynamic Analysis to Process of Hydrostatic Extrusion for Tungsten Alloy

    Institute of Scientific and Technical Information of China (English)

    Fuchi WANG; Zhaohui ZHANG; Shukui LI

    2001-01-01

    The hydrodynamic analysis to the process of the hydrostatic extrusion for tungsten alloy is carried through the hydrodynamic lubrication theory and Reynolds equation in this paper. The critical velocity equation when the hydrodynamic lubrication conditions appear between the surfaces of the work- piece and the die is obtained, and the relationship between the critical velocity and the extrusion parameters is discussed, which build the theoretical bases to the application of the hydrostatic extrusion for tungsten alloy.

  13. Intrusion and extrusion of water in hydrophobic mesopores

    OpenAIRE

    Barrat, Jean-Louis; Lefevre, Benoit; Bocquet, Lyderic; Saugey, Anthony; Vigier, Gérard; Gobin, Pierre-François; Charlaix, Elisabeth

    2003-01-01

    We present experimental and theoretical results on intrusion-extrusion cycles of water in hydrophobic mesoporous materials, characterized by independent cylindrical pores. The intrusion, which takes place above the bulk saturation pressure, can be well described using a macroscopic capillary model. Once the material is saturated with water, extrusion takes place upon reduction of the externally applied pressure; Our results for the extrusion pressure can only be understood by assuming that th...

  14. Solid lipid extrusion of sustained release dosage forms.

    Science.gov (United States)

    Reitz, Claudia; Kleinebudde, Peter

    2007-09-01

    The applicability of the solid lipid extrusion process as preparations method for sustained release dosage forms was investigated in this study. Two lipids with similar melting ranges but of different composition, glyceryl palmitostearate (Precirol ATO 5) and glyceryl trimyristate (Dynasan 114), and mixtures of each lipid with 50% or 75% theophylline were extruded at temperatures below their melting ranges. Extrudates were analyzed using differential scanning calorimetry, scanning electron microscopy, porosity measurements and in vitro drug dissolution studies. The possibility of processing lipids by softening instead of complete melting and without subsequent formation of low-melting, metastable polymorphs could be demonstrated. Extrudates based on formulations of glyceryl palmitostearate/theophylline (50:50) and glyceryl trimyristate/theophylline (50:50) showed sustained release properties. An influence of extrusion conditions on the matrix structure was shown for extrudates based on a mixture of glyceryl trimyristate and theophylline (50:50). Glyceryl trimyristate tended to solidify in porous structures after melting. Exceeding a material temperature of 50.5 degrees C led to porous extrudate matrices with a faster drug release. The production of novel, non porous sustained release matrices was possible at a material temperature of 49.5 degrees C. Extrudates based on glyceryl trimyristate/theophylline (50:50) only slight changes in melting enthalpy and stable drug release profiles.

  15. Propulsion via beam extrusion at low Reynolds number

    CERN Document Server

    Gosselin, Frederick P; Paak, Mehdi

    2014-01-01

    Inspired by microscopic paramecies which use trichocyst extrusion to propel themselves away from thermal aggressions, we propose a macroscopic experiment to study the stability of a slender beam extruded in a highly viscous fluid. Piano wires were extruded axially at constant speed in a tank filled with corn syrup. The force necessary to extrude the wire was measured to increase linearly at first until the compressive viscous force causes the wire to buckle. A numerical model, coupling a lengthening elastica formulation with resistive force theory, predicts a similar behaviour. The model is used to study the dynamics at large time when the beam is highly deformed. It is found that at large time, a large deformation regime exists in which the force necessary to extrude the beam at constant speed becomes constant and length-independent. With a proper dimensional analysis, the beam can be shown to buckle at a critical length based on the extrusion speed, the bending rigidity and the dynamic viscosity of the flui...

  16. A novel polymer extrusion micropelletization process

    Science.gov (United States)

    Aquite, William

    Polymer micropellets provide a variety of potential applications for different processes in the polymer industry. Conventional pellets are in the size range of 2.5 mm to 5 mm, while micropellets are at least ten times smaller, in the size range of 50 μm to 1000 μm. The potential benefits to a processor using micropellets include: high surface to volume ratio, high bulk density, fast and even melting rates in extrusion, improved dry flow properties, faster injection molding cycles, and consequently lower energy consumption during processing. More specialized sintering processes that require polymer powders, such as selective sintering techniques, microporous plastics parts manufacturing, and other powder sintering methods would benefit from the production of polymer micropellets since these exhibit the advantages of pellets yet have a lower average size. This work focuses on the study of a technique developed at the Polymer Engineering Center. The technique uses a microcapillary die for the production of micropellets by causing instabilities in extruded polymer threads deformed using an air stream. Tuning of process conditions allow the development of surface disturbances that promote breakup of the threads into pellets, which are subsequently cooled and collected. Although micropellets with high sphericity and a narrow size distribution can be produced using this technique, minimal changes in process conditions also lead to the production of lenticular pellets as well as pellets, fibers and threads with a wide range of size and shape distributions. This work shows how changing processing conditions achieve a variety of shapes and sizes of micropellets, broadening its application for the production of powders from a variety of polymer resins. Different approaches were used, including dimensional analysis and numerical simulation of the micropelletization process. This research reveals the influence of non-linear viscoelastic effects on the dispersion of a polymer

  17. Continuous extrusion and rolling forming of copper strips

    Directory of Open Access Journals (Sweden)

    Yun Xinbing

    2016-01-01

    Full Text Available Continuous extrusion and rolling technology was proposed as a new strip production technology. It conducts a hot rolling process using waste heat after continuous extrusion. The continuous extrusion and rolling forming was simulated with DEFORM-3DT. Influences of extrusion wheel velocity and rolling reduction on the continuous extrusion and rolling forming were analyzed. It was shown that as extrusion wheel velocity increases, torque of extrusion wheel, chamber force and rolling force, will drop; temperature of the billet in the area of abutment which is highest will increase. As the rolling reduction is increased, torque of the extrusion wheel and force acting on the chamber decrease, while torque and force of the rolls increase. The experimental results showed that a homogeneously distributed and equiaxed grains microstructure can be formed in copper strip billets with an average grain size of about 80 μm, after continuous extrusion. Grains of the copper strips are stretched clearly, during rolling, along the rolling direction, to form a stable orientation. Nevertheless, the grain boundaries are still relatively clear to see.

  18. MODERNIZATION OF TECHNOLOGICAL LINE FOR CELLULAR EXTRUSION PROCESS

    Directory of Open Access Journals (Sweden)

    Tomasz Garbacz

    2014-06-01

    As part of the modernization of the cellular extrusion technology the extrusion head was designed and made. During the designing and modeling of the head the Auto CAD programe was used. After the prototyping the extrusion head was tested. In the article specification of cellular extrusion process of thermoplastics was presented. In the research, the endothermal chemical blowing agents in amount 1,0% by mass were used. The quantity of used blowing agent has a direct influence on density and structure of the extruded product of modified polymers. However, these properties have further influence on porosity, impact strength, hardness, tensile strength and another.

  19. Immediate release pellets with lipid binders obtained by solvent-free cold extrusion.

    Science.gov (United States)

    Krause, Julia; Thommes, Markus; Breitkreutz, Jörg

    2009-01-01

    Lipid-based drug delivery systems have spread in their use in pharmaceutical drug development. This work focuses on the use of lipid binders as alternative non-toxic extrusion aid for pellet formulations. The preparation of immediate release pellets with solid lipid binders through a solvent-free cold extrusion/spheronisation process was investigated in this study. Various binary, ternary and quaternary mixtures of powdered lipids and the model drug sodium benzoate were investigated and compared to well-known wet extrusion binders like microcrystalline cellulose and kappa-carrageenan. The cold lipid extrusion process offers multiple advantages as it is suitable for thermal sensitive as well as for hygroscopic drugs, furthermore no drying process to evaporate the solvent is needed and the process is feasible for different extruder types. Some of the developed pellets showed favourable properties like spherical shape, narrow size distribution, a high drug load of 80% sodium benzoate and a drug release of more than 90% within 40 min. The stability of drug release, which can be problematic when using lipid excipients, was sufficient for some mixtures, as storage under elevated temperatures changed the release profiles only slightly and no formulation released less than 80% within the first 60 min. A formulation with a mixture of hard fat, glycerol distearate and glycerol trimyristate showed the best results, as pellets with a low aspect ratio, narrow size distribution and complete drug release were obtained. Using appropriate mixtures of acylglycerides it becomes possible to produce pharmaceutical pellets with immediate release characteristics by cold extrusion and subsequent spheronisation. Thus, lipids are very promising alternatives to commonly used extrusion/spheronisation binders.

  20. Experimental study and micromechanical modeling of MMT platelet-reinforced PP nanocomposites

    Science.gov (United States)

    Cauvin, Ludovic; Bhatnagar, Naresh; Brieu, Mathias; Kondo, Djimédo

    2007-11-01

    Nanocomposites with platelets reinforcements are emerging materials with strong potential for future engineering applications. The present study is a first step to characterize and predict the elastic behavior of Montmorillonite (MMT) clay reinforced Polypropylene (PP) nanocomposites. The pellets of nanoclay composites were made by first uniformly mixing the MMT platelets in a twin-screw extruder by the melt intercalation route. These pellets were then converted into tensile specimens as per ASTM 638 by injection molding process. From tensile tests it is shown that there is a significant increase of the Young modulus with the mass fraction (2-7%) of clay platelets. A first approach of homogenization allows to conclude that the Ponte Castañeda and Willis (1995) bound predicts the measured moduli provided that a suitable aspect ratio of the reinforcement is considered. To cite this article: L. Cauvin et al., C. R. Mecanique 335 (2007).

  1. Effect of Temperature and Ram Speed on Isothermal Extrusion for Large-size Tube with Piece-wing

    Institute of Scientific and Technical Information of China (English)

    He YANG; Jun ZHANG; Yangmin HE; Bingtao HAN

    2005-01-01

    Heat energy change during the extrusion of 7075 aluminium alloy large-size tube with piece-wing in a container was analyzed. Extrusion load vs ram displacement diagrams and exit temperature vs ram displacement diagrams at various speeds were obtained by 3D FEM simulation. Results show that the exit temperature becomes higher as the ram speed and displacement increase. For large-size tube with piece-wing, there is certainly a curve of ram speed decreasing with increasing ram displacement, which enables isothermal extrusion to be achieved. Therefore,an attempt was made to divide the working stroke into five different zones. Each of them has a preset speed that decreases from the ram displacement beginning to the ending. And then, new exit temperature vs ram displacement diagram was obtained by 3D FEM simulation for the five different speeds. It is shown that the variation of exit temperature is very small. Through the above research, a basic method for realizing isothermal extrusion of 7075large-size tube with piece-wing was obtained, that is, the working stroke was divided into several different zones with a decreasing speed during extrusion, each zones' speed was real-time adjusted on the feedback signal of exit temperature by proportional hydraulic valve through closed-loop control. The engineering experiment verification was carried out on 100 MN aluminium extrusion press with oil-driven double action. The experimental results of the exit temperature agrees with the simulation ones. The achievements of this study may serve as a significant guide to the practice of the relevant processes, particularly for isothermal extrusion. The verified method has been used in the design and manufacture of 125 MN aluminium extrusion press with oil-driven double action.

  2. A comparative study of effect of compatibilization agent on untreated and ultrasonically treated waste ground rubber tire and polyolefin blends

    Directory of Open Access Journals (Sweden)

    Jin Kuk Kim

    2006-12-01

    Full Text Available The development of thermoplastic elastomer blends from waste tire powder and two polyolefins, Viz. maleic anhydride grafted polypropylene and LDPE, was studied. The polymer blends were processed using a twin-screw extruder equipped with a well-designed screw configuration. The blends studied contained a dispersed phase of waste rubber powder obtained from waste tire in a thermoplastic matrix. The effect of ultrasonic treatment on the rubber powder was compared. Contrary to our expectation, ultrasonically treated samples gave poor mechanical properties compared to untreated samples. Significant improvement in the mechanical properties was obtained with the addition of maleic anhydride-grafted styrene-ethylene-butylene-styrene (SEBS-g-MA as a compatibilizer in treated and untreated waste tire powder / polyolefin blends.

  3. THE IMPACT OF EXTRUSION ON THE BIOGAS AND BIOMETHANE YIELD OF PLANT SUBSTRATES

    Directory of Open Access Journals (Sweden)

    Krzysztof Pilarski

    2016-09-01

    Full Text Available The objective of the present work was to determine the effect of pretreatment by extrusion on the biogas and biomethane yield of lignocellulosic substrates such as maize silage and maize straw silage. The biogas yields of the substrates before and after treatment were compared. Moreover, energy efficiency of pretreatment by extrusion was analyzed in order to assess the applicability of the process in an agricultural biogas plant. Extrusion tests were carried out in a short single-screw extruder KZM-2 in which the length-to-diameter ratio of the screw was 6:1 and rotational speed was 200 rpm. The biogas yield tests of the plant substrates after extrusion were carried out in a laboratory scale, using 15 biofermenters operated in a periodic manner, at a constant temperature of 39°C (mesophilic digestion and controlled pH conditions. The gas-emission analysis was performed using a certified gas analyzer from Geotech GA5000. Pretreatment by extrusion was observed to improve the quantity of methane generated: in terms of fresh matter for maize silage subjected to extrusion, the methane yield was 16.48% higher than that of the non-extruded silage. On the other hand, maize straw silage after extrusion gave 35.30% more methane than did the same, non-extruded, material. Differences in yields relative to dry organic matter are also described in this paper. Taking into account the amount of energy that is spent on pretreatment and the generated amount of methane, the energy balance for the process gives an idea of the economics of the operation. For maize silage, energy efficiency was lower by 13.21% (-553.2 kWh/Mg, in contrast to maize straw silage, where the increase in energy was 33.49% (678.4 kWh/Mg. The obtained results indicate that more studies on the pretreatment and digestion of maize silage are required in order to improve the efficiency of its use for making biogas. To fully utilize its potential, it is necessary to know thoroughly the effect of

  4. Extrusion cycles during dome-building eruptions

    Science.gov (United States)

    de' Michieli Vitturi, M.; Clarke, A. B.; Neri, A.; Voight, B.

    2013-06-01

    We identify and quantify controls on the timescales and magnitudes of cyclic (periodic) volcanic eruptions using the numerical model DOMEFLOW (de' Michieli Vitturi et al., 2010) which was developed by the authors for magma systems of intermediate composition. DOMEFLOW treats the magma mixture as a liquid continuum with dispersed gas bubbles and crystals in thermodynamic equilibrium with the melt and assumes a modified Poiseuille form of the viscous term for fully developed laminar flow in a conduit of cylindrical cross-section. During ascent, magma pressure decreases and water vapor exsolves and partially degasses from the melt as the melt simultaneously crystallizes, causing changes in mixture density and viscosity. Two mechanisms previously proposed to cause periodic eruption behavior have been implemented in the model and their corresponding timescales explored. The first applies a stick-slip model in which motion of a shallow solid plug is resisted by static/dynamic friction, as described in Iverson et al. (2006). For a constant magma supply rate at depth, this mechanism yields cyclic extrusion with timescales of seconds to tens of seconds with values generally depending on assumed friction coefficients. The second mechanism does not consider friction but treats the plug as a high-viscosity Newtonian fluid. During viscous resistance, pressure beneath the degassed plug can increase sufficiently to overcome dome overburden, plug weight, and viscous forces, and ultimately drive the plug from the conduit. In this second model cycle periods are on the order of hours, and decrease with increasing magma supply rate until a threshold is reached, at which point periodicity disappears and extrusion rate becomes steady (vanishingly short periods). Magma volatile content for fixed chamber pressure has little effect on cycle timescales, but increasing volatile content increases mass flow rate and cycle magnitude as defined by the difference between maximum and minimum

  5. STRAIN ANALYSIS OF LATERAL EXTRUSION PROCESS

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The strain distribution of equal-cross section lateral extrusion(ECSLE) has been simulated by finite element method. Considering the effect of friction and the width of sample, the simulation results are very close to the reality. The simulated results showed that, around the corner of die, the strain is distributed by sharp layers, and the gradient of the layers is very large, which means that the deformation is just plane shear deformation; the larger the width of sample or the smaller the friction, the more uniform the strain distribution is.

  6. The influence of extrusion on the content of polyphenols and antioxidant/antiradical activity of rye grains (Secale cereale L.

    Directory of Open Access Journals (Sweden)

    Dorota Gumul

    2007-12-01

    Full Text Available The aim of the study was to check the influence of extrusion on the content of polyphenol and antioxidant/antiradical activity of rye grains. The extrudates prepared from three cultivars of rye were obtained at different process parameters. Total polyphenol, antioxidant and antiradical activity was measured in the samples. Extrusion resulted in a decrease of total polyphenol content (TPC on average by 40% in rye grains, and the largest loss of endogenic phenolic compounds was observed at the extrusion conditions: 20% moisture of raw material and 120°C. Extrudates obtained at: 14% moisture of raw material and 180°C exhibited either increase of these compounds or no change. It was found that rye extrudates exhibited the highest antiradical activity (measured by the methods with DPPH and ABTS when raw material contained 14% of moisture and at temperature of the extrusion – 180°C, while the lowest when the parameters were 20% and 120°C. Antioxidant activity in beta-carotene-linoleate model system was high when rye extrusion was performed at 14% and 20% moisture and temperature 180°C. The negative influence of extrusion on the antioxidant activity of rye grains was observed at 20% moisture and 120°C.

  7. Topological defects in epithelia govern cell death and extrusion

    Science.gov (United States)

    Saw, Thuan Beng; Doostmohammadi, Amin; Nier, Vincent; Kocgozlu, Leyla; Thampi, Sumesh; Toyama, Yusuke; Marcq, Philippe; Lim, Chwee Teck; Yeomans, Julia M.; Ladoux, Benoit

    2017-04-01

    Epithelial tissues (epithelia) remove excess cells through extrusion, preventing the accumulation of unnecessary or pathological cells. The extrusion process can be triggered by apoptotic signalling, oncogenic transformation and overcrowding of cells. Despite the important linkage of cell extrusion to developmental, homeostatic and pathological processes such as cancer metastasis, its underlying mechanism and connections to the intrinsic mechanics of the epithelium are largely unexplored. We approach this problem by modelling the epithelium as an active nematic liquid crystal (that has a long range directional order), and comparing numerical simulations to strain rate and stress measurements within monolayers of MDCK (Madin Darby canine kidney) cells. Here we show that apoptotic cell extrusion is provoked by singularities in cell alignments in the form of comet-shaped topological defects. We find a universal correlation between extrusion sites and positions of nematic defects in the cell orientation field in different epithelium types. The results confirm the active nematic nature of epithelia, and demonstrate that defect-induced isotropic stresses are the primary precursors of mechanotransductive responses in cells, including YAP (Yes-associated protein) transcription factor activity, caspase-3-mediated cell death, and extrusions. Importantly, the defect-driven extrusion mechanism depends on intercellular junctions, because the weakening of cell-cell interactions in an α-catenin knockdown monolayer reduces the defect size and increases both the number of defects and extrusion rates, as is also predicted by our model. We further demonstrate the ability to control extrusion hotspots by geometrically inducing defects through microcontact printing of patterned monolayers. On the basis of these results, we propose a mechanism for apoptotic cell extrusion: spontaneously formed topological defects in epithelia govern cell fate. This will be important in predicting

  8. RHEOLOGY OF EXTRUDED WHEY PROTEIN ISOLATE

    Science.gov (United States)

    Whey protein isolate (WPI), a high-quality protein used to fortify a number of foods, may be texturized with a twin-screw extruder. Since extrusion of food is commonly performed above 70°C, which causes whey protein to denature, cold extrusion below 70°C was investigated to determine the effects on...

  9. Caracterização de compósitos produzidos com polietileno de alta densidade (HDPE e serragem da indústria moveleira - parte II - extrusão em dupla-rosca

    Directory of Open Access Journals (Sweden)

    Éverton Hillig

    2011-01-01

    Full Text Available In this work, wood plastic composites made of HDPE and different types of wood sawdust generate at furniture industries are characterised. The equipment used was a 19 mm co-rotating twin-screw extruder, complementing previous studies where the composites were mixed using a single-screw extruder. Temperatures of 180oC were applied at the five heating zones, rotating at 150 rpm with a flux of 1 kg.h-1. Residues of MDF, of loblolly pine and of eucalypt wood were used, and were mixed into the HDPE with a coupling agent (anhydride maleic. Physical characterization of the composites was performed by differential scanning calorimetry (DSC and by scanning electronic microscopy. In addition, the mechanical properties of tension, static bending and impact were analysed, according to ASTM D638, D790 and D256. All types of sawdust acted as a nucleate agent, since the composites showed a crystallinity index higher than pure HDPE. Also, it was observed that the type of sawdust influenced fibre¿s dispersion in the polymeric matrix. The mechanical tests showed differences in the properties of the composites made of different types of sawdust. In general, inclusion of MDF sawdust resulted in composites with higher bending strength and impact work than those containing eucalypt and pine. Comparing results obtained using a single-screw extruder and values obtained in this study, it can be concluded that the properties of the wood are more effectively transferred to the composite using a double-screw extruder.

  10. Evaluation of sorghum flour as extender in plywood adhesives for sprayline coaters or foam extrusion

    Science.gov (United States)

    This study was conducted to evaluate sorghum flour as protein extender in plywood adhesive for sprayline coaters or foam extrusion. Defatted sorghum flour, containing 0.2% (dry basis, db) residual oil and 12.0% (db) crude protein, was analyzed for solubility and foaming properties. Sorghum flour pr...

  11. Effect of needle insertion depth and root canal curvature on irrigant extrusion ex vivo

    NARCIS (Netherlands)

    Psimma, Z.; Boutsioukis, C.; Kastrinakis, E.; Vasiliadis, L.

    2013-01-01

    Introduction The aim of this study was to evaluate the effect of needle type and insertion depth, apical preparation size, and root canal curvature on irrigant extrusion by using a recently introduced method. Methods Sixteen human teeth with a straight root canal (group A) and 16 with a moderatel

  12. Efficient encapsulation of plasmid DNA in anionic liposomes by a freeze/thaw extrusion procedure

    NARCIS (Netherlands)

    Schoen, P; Bijl, L; Wilschut, J

    1998-01-01

    In this study we investigated whether intact plasmid DNA can be efficiently encapsulated in anionic liposomes prepared by freeze/thaw and extrusion techniques. There is controversy about this method of DNA encapsulation, especially as to whether DNA remains intact and retains its biological activity

  13. 75 FR 34482 - Certain Aluminum Extrusions From China

    Science.gov (United States)

    2010-06-17

    ... Commission, Washington, DC, and by publishing the notice in the Federal Register of April 6, 2010 (75 FR... COMMISSION Certain Aluminum Extrusions From China Determinations On the basis of the record \\1\\ developed in... reason of imports from China of certain aluminum extrusions, provided for in subheadings 7604.21,...

  14. 76 FR 29007 - Certain Aluminum Extrusions From China

    Science.gov (United States)

    2011-05-19

    ... in the Federal Register on December 22, 2010 (75 FR 80527). The hearing was held in Washington, DC... COMMISSION Certain Aluminum Extrusions From China Determinations On the basis of the record \\1\\ developed in... certain aluminum extrusions from ] China other than finished heat sinks, provided for in subheadings...

  15. Material testing of copper by extrusion-cutting

    DEFF Research Database (Denmark)

    Segalina, F.; De Chiffre, Leonardo

    2017-01-01

    was developed and implemented on a CNC lathe. An investigation was carried out extrusion-cutting copper discs using high-speed-steel cutting tools at 100 m/min cutting speed. Flow stress values for copper under machining-relevant conditions were obtained from measurement of the extrusion-cutting force...

  16. CAD implementation of design rules for aluminium extrusion dies

    NARCIS (Netherlands)

    Ouwerkerk, van Gijs

    2009-01-01

    Aluminium extrusion is an industrial forming process that is used to produce long profiles of a constant cross-section. This cross-section is shaped by the opening in a steel tool known as the die. The understanding of the mechanics of the aluminium extrusion process is still limited. The flow of al

  17. Study of processing conditions on properties of ABS and clay organically modified nanocomposites; Estudo das condicoes de processamento nas propriedades de nanocompositos de ABS e argilas organofilicas

    Energy Technology Data Exchange (ETDEWEB)

    Galvan, Danieli; Massucato, Felipe; Bartoli, Julio R., E-mail: bartoli@feq.unicamp.br [Fac. de Engenharia Quimica/Universidade Estadual de Campinas - DTP/FEQ/UNICAMP, Campinas, SP (Brazil); D' Avila, Marcos A. [Fac. de Engenharia Mecanica/Universidade Estadual de Campinas - DEMA/FEM/UNICAMP, Campinas, SP (Brazil); Fernandes, Elizabeth G. [Tezca P and D Celulas Solares, Campinas, SP (Brazil)

    2011-07-01

    Nanocomposites of poly(acrylonitrile-butadiene-styrene) and organically modified montmorillonite clay were prepared by melt intercalation on a co-rotating twin-screw extruder. The independent variables studied were the kind of organoclay (Cloisite 20A and Cloisite 30B) and the screw torque at levels of 45 and 70%. The effect of these variables on the intercalation/exfoliation were accessed by means of the morphological characteristics using X-ray diffraction and the mechanical properties of uniaxial tensile test. The experimental results showed that the incorporation of clay in the polymeric matrix improved the mechanical properties of elastic modulus, yield stress and tensile strength of nanocomposites, being more significant for that containing Cloisite 30B. Torque was also a significant variable for the responses studied. (author)

  18. Abl suppresses cell extrusion and intercalation during epithelium folding.

    Science.gov (United States)

    Jodoin, Jeanne N; Martin, Adam C

    2016-09-15

    Tissue morphogenesis requires control over cell shape changes and rearrangements. In the Drosophila mesoderm, linked epithelial cells apically constrict, without cell extrusion or intercalation, to fold the epithelium into a tube that will then undergo epithelial-to-mesenchymal transition (EMT). Apical constriction drives tissue folding or cell extrusion in different contexts, but the mechanisms that dictate the specific outcomes are poorly understood. Using live imaging, we found that Abelson (Abl) tyrosine kinase depletion causes apically constricting cells to undergo aberrant basal cell extrusion and cell intercalation. abl depletion disrupted apical-basal polarity and adherens junction organization in mesoderm cells, suggesting that extruding cells undergo premature EMT. The polarity loss was associated with abnormal basolateral contractile actomyosin and Enabled (Ena) accumulation. Depletion of the Abl effector Enabled (Ena) in abl-depleted embryos suppressed the abl phenotype, consistent with cell extrusion resulting from misregulated ena Our work provides new insight into how Abl loss and Ena misregulation promote cell extrusion and EMT.

  19. Friction measurement and modelling in forward rod extrusion

    DEFF Research Database (Denmark)

    Tan, Xincai; Bay, Niels; Zhang, Wenqi

    2003-01-01

    Forward extrusion is one of the important processes in bulk metal forming. Friction stress can be estimated from the slope of the load±displacement curve at the steady state after the maximum load in a forward extrusion test. In this paper, forward rod extrusion tests are carried out to determine...... experimentally friction stress at various normal pressures, reductions in area, billet heights and lubrications. Tested materials include aluminium alloy, low carbon steel and stainless steel. Two lubrication methods are applied, conversion coating followed by either alkaline soap or molybdenum disulphide...... as the lubricant. Friction stresses are obtained from measurements of slopes of extrusion pressure±punch travel curves at the steady state stage. Normal pressures are evaluated by using Mohr’s circle, in which shear ¯ow stresses are estimated at the maximum elastic deformation points from the same extrusion...

  20. Effects of extrusion cooking on physicochemical properties of white and red ginseng (powder)

    Science.gov (United States)

    Gui, Ying; Ryu, Gi-Hyung

    2013-01-01

    A systematic comparison of the physicochemical properties of white ginseng (WG), extruded white ginseng (EWG), red ginseng (RG), and extruded red ginseng (ERG) was performed. The aim of the present study was to identify the effects of the physicochemical properties of ginseng by extrusion cooking. The highest value of the water absorption index (WAI) was 3.64 g/g obtained from EWG, and the highest value of the water solubility index (WSI) was 45.27% obtained from ERG. The ERG had a better dispersibility compared with other samples. Extrusion cooking led to a significant increase in acidic polysaccharide and total sugar content but resulted in a decrease in crude fat and reducing sugar contents. Enzyme treatment led to a sharp increase in acidic polysaccharide content, especially the cellulose enzyme. Extrusion cooking led to a significant increase in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power, and the increases in WG and RG were 13.56% (0.038) and 3.56% (0.026), respectively. The data of this study provide valuable information about the effects of extrusion on quality changes of EWG and ERG. PMID:24748839

  1. Cryogenic pellet production developments for long-pulse plasma operation

    Energy Technology Data Exchange (ETDEWEB)

    Meitner, S. J.; Baylor, L. R.; Combs, S. K.; Fehling, D. T.; McGill, J. M.; Duckworth, R. C.; McGinnis, W. D.; Rasmussen, D. A. [Oak Ridge National Laboratory, 1Bethel Valley Rd Oak Ridge, TN 37831 (United States)

    2014-01-29

    Long pulse plasma operation on large magnetic fusion devices require multiple forms of cryogenically formed pellets for plasma fueling, on-demand edge localized mode (ELM) triggering, radiative cooling of the divertor, and impurity transport studies. The solid deuterium fueling and ELM triggering pellets can be formed by extrusions created by helium cooled, twin-screw extruder based injection system that freezes deuterium in the screw section. A solenoid actuated cutter mechanism is activated to cut the pellets from the extrusion, inserting them into the barrel, and then fired by the pneumatic valve pulse of high pressure gas. Fuel pellets are injected at a rate up to 10 Hz, and ELM triggering pellets are injected at rates up to 20 Hz. The radiative cooling and impurity transport study pellets are produced by introducing impurity gas into a helium cooled section of a pipe gun where it deposits in-situ. A pneumatic valve is opened and propellant gas is released downstream where it encounters a passive punch which initially accelerates the pellet before the gas flow around the finishes the pellet acceleration. This paper discusses the various cryogenic pellet production techniques based on the twin-screw extruder, pipe gun, and pellet punch designs.

  2. Genetic Architecture of Anther Extrusion in Spring and Winter Wheat

    Directory of Open Access Journals (Sweden)

    Quddoos H. Muqaddasi

    2017-05-01

    Full Text Available Hybrid wheat breeding is gaining prominence worldwide because it ensures higher and more static yield than conventionally bred varieties. The cleistogamous floral architecture of wheat (Triticum aestivum L. impedes anthers inside the floret, making it largely an inbreeder. For hybrid seed production, high anther extrusion is needed to promote cross pollination and to ensure a high level of pollen availability for the seed plant. This study, therefore, aimed at the genetic dissection of anther extrusion (AE in panels of spring (SP, and winter wheat (WP accessions by genome wide association studies (GWAS. We performed GWAS to identify the SNP markers potentially linked with AE in each panel separately. Phenotypic data were collected for 3 years for each panel. The average levels of Pearson's correlation (r among all years and their best linear unbiased estimates (BLUEs within both panels were high (r(SP = 0.75, P < 0.0001;r(WP = 0.72, P < 0.0001. Genotypic data (with minimum of 0.05 minor allele frequency applied included 12,066 and 12,191 SNP markers for SP and WP, respectively. Both genotypes and environment influenced the magnitude of AE. In total, 23 significant (|log10(P| > 3.0 marker trait associations (MTAs were detected (SP = 11; WP = 12. Anther extrusion behaved as a complex trait with significant markers having either favorable or unfavorable additive effects and imparting minor to moderate levels of phenotypic variance (R2(SP = 9.75−14.24%; R2 (WP = 9.44−16.98%. All mapped significant markers as well as the markers within their significant linkage disequilibrium (r2 ≥ 0.30 regions were blasted against wheat genome assembly (IWGSC1+popseq to find the corresponding genes and their high confidence descriptions were retrieved. These genes and their orthologs in Hordeum vulgare, Brachypodium distachyon, Oryza sativa, and Sorghum bicolor revealed syntenic genomic regions potentially involved in flowering-related traits. Moreover, the

  3. Characterization of extrusion flow using particle image velocimetry

    Directory of Open Access Journals (Sweden)

    2009-09-01

    Full Text Available The aim of this study was the characterization of polymer flows within an extrusion die using particle image velocimetry (PIV in very constraining conditions (high temperature, pressure and velocity. Measurements were realized on semi-industrial equipments in order to have test conditions close to the industrial ones. Simple flows as well as disrupted ones were studied in order to determine the capabilities and the limits of the method. The analysis of the velocity profiles pointed out significant wall slip, which was confirmed by rheological measurements based on Mooney's method. Numerical simulations were used to connect the two sets of measurements and to simulate complex velocity profiles for comparison to the experimental ones. A good agreement was found between simulations and experiments providing wall slip is taken into account in the simulation.

  4. Visualization of the Crystallization in Foam Extrusion Process

    Science.gov (United States)

    Tabatabaei Naeini, Alireza

    In this study, crystal formation of polypropylene (PP) and poly lactic acid (PLA) in the presence of CO2 in foam extrusion process was investigated using a visualization chamber and a CCD camera. The role of pre-existing crystals on the foaming behavior of PP and PLA were studied by characterizing the foam morphology. Visualization results showed that crystals formed within the die before foaming and these crystals affect the cell nucleation behavior and expansion ratio of PP and PLA significantly. Due to the fast crystallization kinetics of PP, crystallinity should be optimum to achieve uniform cell structure with high cell density and high expansion ratio. In PLA, enhancement of crystallinity is crucial for getting foam with a high expansion ratio. It was also visualized that CO2 significantly suppresses the crystallization temperature in PP through the plasticization effect as well as its influence on flow induced crystallinity.

  5. The Core Extrusion Schema-Revised: Hiding Oneself Predicts Severity of Social Interaction Anxiety.

    Science.gov (United States)

    Levinson, Cheri A; Rodebaugh, Thomas L; Lim, Michelle H; Fernandez, Katya C

    2017-01-01

    Cognitive behavioral models of social anxiety disorder (SAD) suggest that fear of negative evaluation is a core fear or vulnerability for SAD. However, why negative evaluation is feared is not fully understood. It is possible that core beliefs contribute to the relationship between fear of negative evaluation and SAD. One of these beliefs may be a core extrusion schema: a constellation of beliefs that one's true self will be rejected by others and therefore one should hide one's true self. In the current study (N = 699), we extended research on the Core Extrusion Schema and created a shortened and revised version of the measure called the Core Extrusion Schema-Revised The Core Extrusion Schema-Revised demonstrated good factor fit for its two subscales (Hidden Self and Rejection of the True Self) and was invariant across gender and ethnicity. The Hidden Self subscale demonstrated excellent incremental validity within the full sample as well as in participants diagnosed with generalized SAD. Specifically, the Hidden Self subscale may help explain severity of social interaction anxiety. This measure could be used with individuals diagnosed with generalized SAD to design exposures targeting these core beliefs.

  6. Effect of fermentation and extrusion on the release of selected minerals from lupine grain preparations

    Directory of Open Access Journals (Sweden)

    Rafał W. Wójciak

    2009-09-01

    Full Text Available Introduction. Antinutritional factors in legumes lower the nutritional value of foods by lowering the digestibility or bioavailability of nutrients. Technological processes applied in food production (e.g. extrusion, fermentation, germination may influence the leguminous seeds matrix composition which in consequence may affect (improve or decrease mineral bioaccessibility and uptake in animals and humans. The aim of this study was to determine the effect of fermentation and extrusion processing, as well as their combination, on the potential availability of Fe, Cu, and Zn from lupine grain preparations. Materials and methods. The content and the release of Fe, Cu and Zn from three different lupine species (Lupinus albus, Lupinus luteus, Lupinus angustifolius was determined. The samples were subjected to enzymatic digestion under in vitro conditions. The content of minerals in lupine grains before and after enzymatic digestion was determined by the flame atomic absorption spectrometry. Results. The degree of release of Fe, Cu, and Zn from dehulled lupine grains was higher than from whole grains. Fermentation processing increased the degree of Fe release, extrusion decreased the degree of Cu release, while the extrusion after fermentation processing increased the degree of Fe release from lupine grain preparations. Conclusions. The degree of mineral release from lupine grains depends on the hull content, technological processing applied and the lupine variety.

  7. Co-extrusion as manufacturing technique for fixed-dose combination mini-matrices.

    Science.gov (United States)

    Dierickx, L; Saerens, L; Almeida, A; De Beer, T; Remon, J P; Vervaet, C

    2012-08-01

    The aim of this study was to develop a multilayer (core/coat) dosage form via co-extrusion, the core providing sustained drug release and the coat immediate drug release. In this study polymers were selected which can be combined in a co-extruded dosage form. Several thermoplastic polymers were hot-melt extruded and evaluated for processability and macroscopic properties (surface smoothness, die swell). Metoprolol tartrate (MPT) and hydrochlorothiazide (HCT) were incorporated as sustained and immediate release model drugs, respectively. Based on the polymer screening experiments a combination of polycaprolactone (core) and polyethylene oxide (coat) was selected for co-extrusion trials, taking into account their drug release profiles and extrusion temperature (70 °C). This combination (containing 10% HCT in the coat and 45% MPT in the core) was successfully co-extruded (diameter core: 3 mm/thickness coat: 0.5 mm). Adhesion between the two polymer layers was good. HCT release from the coat was complete within 30 min, while MPT release was sustained over 24 h (55%, 70%, 85% and 100% after 4, 8, 12 and 2 4h, respectively). DSC, XRD and Raman spectroscopy revealed that MPT remained crystalline during extrusion, whereas HCT was dissolved in the polyethylene oxide matrix. The in vivo study revealed no significant differences between the experimental formulation and the reference formulation (Zok-Zid tablet). Fixed-dose combination mini-tablets with good in vitro and in vivo performance were successfully developed by means of co-extrusion, using a combination of polycaprolactone and polyethylene oxide.

  8. Study on the mechanical properties of a HMS-PP nanocomposite with a Brazilian bentonite; Estudo das propriedades mecanicas de um nanocomposito de HMS-PP com uma bentonita brasileira

    Energy Technology Data Exchange (ETDEWEB)

    Fermino, D.M.; Parra, D.F.; Lugao, A.B.; Oliani, W.L., E-mail: mfermino@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Valenzuela-Diaz, F.R. [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Metalurgica e de Materiais

    2010-07-01

    This work concerns to the study of the mechanical behavior of the nanocomposite HMSPP - Polypropylene High Melt Strength (obtained at a dose of 12.5 kGy) and a bentonite clay Brazilian Paraiba (PB), known as 'Chocolate' in concentrations of 5 and 10% by weight, comparison of to one American Clay, cloisite 20A nanocomposite was done. Agent compatibilizer polypropylene-graft, known as maleic anhydride (PP-g-AM) was addict 3% concentration thought technique melt intercalation using a twin-screw extruder and the specimens were prepared by injection process. The mechanical behavior was evaluated by strength, flexural strength and impact tests. The morphology of the nanocomposites was studied by the technique of Scanning Electron Microscopy (SEM), while the organophilic bentonite and nanocomposites were characterized by X-ray diffraction (XRD) and infrared (FTIR). (author)

  9. Pellet manufacturing by extrusion-spheronization using process analytical technology

    DEFF Research Database (Denmark)

    Sandler, Niklas; Rantanen, Jukka; Heinämäki, Jyrki

    2005-01-01

    The aim of this study was to investigate the phase transitions occurring in nitrofurantoin and theophylline formulations during pelletization by extrusion-spheronization. An at-line process analytical technology (PAT) approach was used to increase the understanding of the solid-state behavior...... hydrate (nitrofurantoin), dehydration was observed at higher temperatures. To reach an understanding of the process and to find the critical process parameters, the use of complementary analytical techniques are absolutely necessary when signals from APIs and different excipients overlap each other....... of the active pharmaceutical ingredients (APIs) during pelletization. Raman spectroscopy, near-infrared (NIR) spectroscopy, and X-ray powder diffraction (XRPD) were used in the characterization of polymorphic changes during the process. Samples were collected at the end of each processing stage (blending...

  10. A Review of Dynamic Models of Hot-Melt Extrusion

    Directory of Open Access Journals (Sweden)

    Jonathan Grimard

    2016-06-01

    Full Text Available Hot-melt extrusion is commonly applied for forming products, ranging from metals to plastics, rubber and clay composites. It is also increasingly used for the production of pharmaceuticals, such as granules, pellets and tablets. In this context, mathematical modeling plays an important role to determine the best process operating conditions, but also to possibly develop software sensors or controllers. The early models were essentially black-box and relied on the measurement of the residence time distribution. Current models involve mass, energy and momentum balances and consists of (partial differential equations. This paper presents a literature review of a range of existing models. A common case study is considered to illustrate the predictive capability of the main candidate models, programmed in a simulation environment (e.g., MATLAB. Finally, a comprehensive distributed parameter model capturing the main phenomena is proposed.

  11. Thermal modelling of extrusion based additive manufacturing of composite materials

    DEFF Research Database (Denmark)

    Jensen, Mathias Laustsen; Sonne, Mads Rostgaard; Hattel, Jesper Henri

    2017-01-01

    One of the hottest topics regarding manufacturing these years is additive manufacturing (AM). AM is a young branch of manufacturing techniques, which by nature is disruptive due to its completely different manufacturing approach, wherein material is added instead of removed. By adding material...... process knowledge, and validating the generated toolpaths before the real manufacturing process takes place: Hence removing time consuming and expensive trial-and-error processes for new products. This study applies a 2D restricted finite volume model aimed to describe thermoplastic Acrylonitrille......-butadiene-styrene (ABS) and thermosetting polyurethane (PU) material extrusion processes. During the experimental evaluation of the produced models it is found that some critical material properties needs to be further investigated to increase the precision of the model. It is however also found that even with only...

  12. On the potential for lunar highlands Mg-suite extrusive volcanism and implications concerning crustal evolution

    Science.gov (United States)

    Prissel, Tabb C.; Whitten, Jennifer L.; Parman, Stephen W.; Head, James W.

    2016-10-01

    The lunar magnesian-suite (Mg-suite) was produced during the earliest periods of magmatic activity on the Moon. Based on the cumulate textures of the samples and a lack of evidence for Mg-suite extrusives in both the sample and remote sensing databases, several petrogenetic models deduce a predominantly intrusive magmatic history for Mg-suite lithologies. Considering that ∼18% of the lunar surface is covered by mare basalt flows, which are substantially higher in density than estimated Mg-suite magmas (∼2900 versus ∼2700 kg/m3), the apparent absence of low-density Mg-suite volcanics is surprising. Were Mg-suite magmas predominantly intrusive, or have their extrusive equivalents been covered by subsequent impact ejecta and/or later stage volcanism? If Mg-suite magmas were predominantly intrusive, what prevented these melts from erupting? Or, if they are present as extrusives, what regions of the Moon are most likely to contain Mg-suite volcanic deposits? This study investigates buoyancy-driven ascent of Mg-suite parental melts and is motivated by recent measurements of crustal density from GRAIL. Mg-suite dunite, troctolite, and spinel anorthosite parental melts (2742, 2699, and 2648 kg/m3, respectively) are considered, all of which have much lower melt densities relative to mare basalts and picritic glasses. Mg-suite parental melts are more dense than most of the crust and would not be expected to buoyantly erupt. However, about 10% of the lunar crust is greater in density than Mg-suite melts. These areas are primarily within the nearside southern highlands and South Pole-Aitken (SP-A) basin. Mg-suite extrusions and/or shallow intrusions were possible within these regions, assuming crustal density structure at >4.1 Ga was similar to the present day crust. We review evidence for Mg-suite activity within both the southern highlands and SP-A and discuss the implications concerning crustal evolution as well as Mg-suite petrogenesis. Lower crustal densities

  13. Eulerian hydrocode modeling of a dynamic tensile extrusion experiment (u)

    Energy Technology Data Exchange (ETDEWEB)

    Burkett, Michael W [Los Alamos National Laboratory; Clancy, Sean P [Los Alamos National Laboratory

    2009-01-01

    Eulerian hydrocode simulations utilizing the Mechanical Threshold Stress flow stress model were performed to provide insight into a dynamic extrusion experiment. The dynamic extrusion response of copper (three different grain sizes) and tantalum spheres were simulated with MESA, an explicit, 2-D Eulerian continuum mechanics hydrocode and compared with experimental data. The experimental data consisted of high-speed images of the extrusion process, recovered extruded samples, and post test metallography. The hydrocode was developed to predict large-strain and high-strain-rate loading problems. Some of the features of the features of MESA include a high-order advection algorithm, a material interface tracking scheme and a van Leer monotonic advection-limiting. The Mechanical Threshold Stress (MTS) model was utilized to evolve the flow stress as a function of strain, strain rate and temperature for copper and tantalum. Plastic strains exceeding 300% were predicted in the extrusion of copper at 400 m/s, while plastic strains exceeding 800% were predicted for Ta. Quantitative comparisons between the predicted and measured deformation topologies and extrusion rate were made. Additionally, predictions of the texture evolution (based upon the deformation rate history and the rigid body rotations experienced by the copper during the extrusion process) were compared with the orientation imaging microscopy measurements. Finally, comparisons between the calculated and measured influence of the initial texture on the dynamic extrusion response of tantalum was performed.

  14. Study on Numerical Simulation of Hot Extrusion Process of Automobile's Hollow Front Axle%汽车前桥空心短轴的热挤压成形工艺数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    韦国强; 管延锦; 朱立华; 解振东; 孙德朋

    2016-01-01

    A hot extrusion process was proposed to improve the productivity and the material utilization in the manufacture of automobile's hollow front axle . Numerical simulations under various conditions designed by the orthogonal method were done to optimize parameters of the final step of hot extrusion process . Finally the production efficiency , material utilization and product quality were improved and the optimal shaping quality was achieved .%针对某汽车前桥短轴类零件成形制造中存在的生产效率和材料利用率低的问题,提出并设计了热挤压成形制造工艺。通过正交法设计多组参数条件进行数值模拟,实现了热挤压终成形工步的工艺参数优化,获得了最优的成形效果,达到了提高生产效率、材料利用率以及零件质量的目标。

  15. 正挤横轧式农用车后桥半轴套管的研究开发%Study and Development of the Rear Axle Shaft Sleeves of Farm Transport Vehicle by Forward Extrusion and Cross Rolling

    Institute of Scientific and Technical Information of China (English)

    韩英淳; 王学明; 唐志强

    2001-01-01

    在成功地开发轻型车正挤与横轧式后桥半轴套管的基础上,自主开发了1608型、2310型及2815型农用运输车的正挤与横轧式后桥半轴套管,并实现系列化规模生产,获得了显著的社会经济效益。%On the basis of the development of the rear axle shaft sleeve of the light truck CA1040 by forward extrusion and cross rolling, to adapt to the rapid growth of farm transport vehicle, the rear axle shaft sleeve of farm transport vehicle 1608,2310,2815 have been developed successively and manufactured on a big scale. In accordance with the characteristic in geometrical shape of the rear axle shaft sleeve, we change it into a detached structure based on the equal strength theory. Since the detached sleeve bodies have a small difference in diameter, they can be formed with technology of the forward extrusion and cross rolling.

  16. Towards Extrusion of Ionomers to Process Fuel Cell Membranes

    Directory of Open Access Journals (Sweden)

    Jean-Yves Sanchez

    2011-07-01

    Full Text Available While Proton Exchange Membrane Fuel Cell (PEMFC membranes are currently prepared by film casting, this paper demonstrates the feasibility of extrusion, a solvent-free alternative process. Thanks to water-soluble process-aid plasticizers, duly selected, it was possible to extrude acidic and alkaline polysulfone ionomers. Additionally, the feasibility to extrude composites was demonstrated. The impact of the plasticizers on the melt viscosity was investigated. Following the extrusion, the plasticizers were fully removed in water. The extrusion was found to impact neither on the ionomer chains, nor on the performances of the membrane. This environmentally friendly process was successfully validated for a variety of high performance ionomers.

  17. A new engineering model for understanding extrusion process

    DEFF Research Database (Denmark)

    Cheng, Hongyuan; Friis, Alan

    A new engineering method is proposed to understand extrudate expansion and extrusion operation parameters for starch based food extrusion cooking process through dimensional analysis principle, i.e. Buckingham pi theorem. Three dimensionless groups, i.e. pump efficiency, water content...... and temperature, are suggested to describe the extrudate expansion. Using the three dimensionless groups, an equation is derived to express the extrudate expansion. The model has been used to correlate the experimental data for whole wheat flour and fish feed extrusion cooking. The average deviations...

  18. Orthodontic extrusion in the transitional dentition: a simple technique.

    LENUS (Irish Health Repository)

    Darby, Laura J

    2009-11-01

    Extrusion of teeth may be necessary in cases of delayed eruption, primary retention, traumatically intruded teeth, or subgingivally fractured teeth. Removable appliances are advantageous, as anchorage is not as tooth-dependant as in the case of fixed appliances. They are cost-effective, operator friendly, and a valuable treatment option to consider in cases where extrusion of anterior teeth in the transitional dentition is necessary. The purpose of this paper was to describe a simple, cost-effective technique using a removable appliance for extrusion of incisors in the transitional dentition.

  19. Numerical and experimental investigations on an extrusion process for a newly developed ultra-high-carbon lightweight steel for the automotive industry

    Science.gov (United States)

    Behrens, B.-A.; Bouguecha, A.; Bonk, C.; Yarcu, D.; Kazhai, M.

    2017-02-01

    In this study the material flow of a newly developed ultra-high-carbon lightweight steel (uhc-steel) with a high amount of aluminum was investigated in an extrusion process. Cylinder compression tests were performed for material characterization and frictional behaviour was determined by using ring compression tests. Numerical simulations were carried to determine the optimal die geometry as well as to calculate the process loads and dominated stresses in the die occurring during the process. Based on the numerical results, an extrusion process was designed and implemented. Experiments showed that the uhc-steel can be formed by extrusion however it is associated with a high wear rate.

  20. The counter-rotating twin screw extruder as a polymerization reactor

    NARCIS (Netherlands)

    Ganzeveld, Klaassien Jakoba

    1992-01-01

    The goal of the research was to examine the possibilities of this type of extruder as a polymerization reactor, and to develop models of the extruder reactor which accurately describe the reaction progress in the extruder. See summary

  1. Distribution of binder in granules produced by means of twin screw granulation

    DEFF Research Database (Denmark)

    Fonteyne, Margot; Fussell, Andrew Luke; Vercruysse, Jurgen

    2014-01-01

    -granular distribution of PVP was evaluated by means of hyperspectral coherent anti-Stokes Raman scattering (CARS) microscopy. For the evaluated formulation, no PVP rich zones were detected when applying a lateral spatial resolution of 0.5 μm, indicating that PVP is homogenously distributed within the granules....

  2. Request Twin Screw Extruder to Enhance DoD Interested Polymer Nanocomposite Research and STEM Program

    Science.gov (United States)

    2016-09-25

    The polymer systems including plastics and modified plastics including polyester, nylon, polyolefin, polystyrene, polyurea, polyurethane, polyamide...substantial and unprecedented history of educating, training, and mentoring underrepresented groups, the enhanced research capabilities and education

  3. Development Of An Industrial High Temperature Heat Pump With Twin Screw Compressor

    OpenAIRE

    He, Yongning; Yang, Dongfang; Cao, Feng; Li, Gang

    2014-01-01

    In industrial applications, 90-150? hot water needed during production processes is traditionally provided by fuel-fired boilers. The usage of fuel-fired boiler has a low efficiency of energy use and potential danger of explosion. 30-60?waste water with large amount of energy is rejected to environment directly, which causes a great energy loss and thermal pollution. Seeking for a much high efficiency and safe heating pattern is essential to replace the boilers used now. High temperature heat...

  4. Run-in coatings for twin-screw machines; Einlaufschichten in Schraubenmaschinen

    Energy Technology Data Exchange (ETDEWEB)

    Kauder, K.; Bach, F.W. [Dortmund Univ. (Germany). Lehrstuhl fuer Werkstofftechnologie; Unterberg, W. [Dortmund Univ. (Germany). Lehrstuhl fuer Werkstofftechnologie; Dortmund Univ. (Germany). Fachgebiet Fluidenergiemaschinen

    1999-07-01

    In this paper new results of research regarding the efforts of run-in-coatings and corrosion resistant coatings for machines of the displacement type are described. The aim of the investigations are the development and testing of the new coating systems. In order to improve the reliability and operational behaviour of screw-type machines and to repair their machine's casing the procedure of atmospheric plasma spraying was used. The coatings developed for the rotors were deposited by a conventional plasma torch, while the coatings provided for the inside of the casing were deposited by the additional use of an internal torch. In both cases coating systems were manufactured, which consist of a NiCrAl bond coat and a ceramic top coat (7% yttria stabilized zirconia). In a first step parameter investigations concerning different powders were carried out. After this the coatings were applied to various substrate materials with different spraying distances in order to achieve a porous structure of the top coating. These porous structure turned out to be necessary for good run-in-properties. Furthermore corrosion testings of these coating systems were made. (orig.) [German] Im vorliegenden Beitrag wird ueber neue Forschungsergebnisse im Hinblick auf Einlauf- bzw. Korrosionsschutzschichten fuer den Einsatz in Rotationsverdraengermaschinen berichtet, wobei das Ziel der hier beschriebenen Untersuchungen in der Herstellung und Pruefung des hergestellten Werkstoffverbundes liegt. Um das Betriebsverhalten und die Betriebssicherheit von Schraubenmaschinen weiter verbessern zu koennen, als auch geometrieerhaltende Reparaturbeschichtungen an Schraubenmaschinengehaeusen durchzufuehren, werden in einem ersten Schritt mit Hilfe des atmosphaerischen Plasmaspritzens (APS) verschiedenartige Schichtsysteme auf Probekoerper aufgebracht. Dabei kommen ein konventioneller APS-Brenner fuer die Rotorbeschichtung und ein Innenbrenner fuer das Beschichten der Gehaeuse zur Anwendung. Als Werkstoff fuer die Einlaufbeschichtungen wird ZrO{sub 2}7Y{sub 2}O{sub 3} verwendet, als Haftvermittler- bzw. Korrosionsschutzschicht dient NiCrAl. Ausgehend von umfangreichen Parameterstudien fuer die Verarbeitbarkeit der eingesetzten Pulver beschaeftigt sich ein weiterer Schwerpunkt mit den Spritzabstandsuntersuchungen, um die gewuenschte Schichtporositaet einzustellen und damit verbunden die Einlauffaehigkeit der Schicht zu gewaehrleisten. Zudem werden an hergestellten Werkstoffverbunden anwendungsangepasste Korrosionsuntersuchungen an Probekoerpern durchgefuehrt. (orig.)

  5. Fast Pyrolysis of Biomass Residues in a Twin-screw Mixing Reactor.

    Science.gov (United States)

    Funke, Axel; Richter, Daniel; Niebel, Andreas; Dahmen, Nicolaus; Sauer, Jörg

    2016-09-09

    Fast pyrolysis is being increasingly applied in commercial plants worldwide. They run exclusively on woody biomass, which has favorable properties for conversion with fast pyrolysis. In order to increase the synergies of food production and the energetic and/or material use of biomass, it is desirable to utilize residues from agricultural production, e.g., straw. The presented method is suitable for converting such a material on an industrial scale. The main features are presented and an example of mass balances from the conversion of several biomass residues is given. After conversion, fractionated condensation is applied in order to retrieve two condensates - an organic-rich and an aqueous-rich one. This design prevents the production of fast pyrolysis bio-oil that exhibits phase separation. A two phase bio-oil is to be expected because of the typically high ash content of straw biomass, which promotes the production of water of reaction during conversion. Both fractionated condensation and the use of biomass with high ash content demand a careful approach for establishing balances. Not all kind of balances are both meaningful and comparable to other results from the literature. Different balancing methods are presented, and the information that can be derived from them is discussed.

  6. Experimental investigation and numerical simulation of large-sized aluminum tube extrusion forming

    Institute of Scientific and Technical Information of China (English)

    吕亚臣; 骆俊廷; 马春荣; 徐岩

    2008-01-01

    Large-sized aluminum tube has big section effect, aspect ratio and thin thickness, so that the extrusion technology is complex and the large specific pressure is generated in extrusion cavity. The temperature variation and velocity effect is difficult to control. The extrusion forming of large-sized aluminum tube was researched and simulated. Three-dimensional thermo-mechanical coupled finite element model was constructed and appropriate boundary conditions were given out. The results show that large-sized aluminum tube can be formed by isothermal extrusion through controlling the extrusion velocity and founding the relationship between extrusion velocity and extrusion temperature.

  7. Optimization of mechanical and damping properties of Mg–0.6Zr alloy by different extrusion processing

    Directory of Open Access Journals (Sweden)

    Jingfeng Wang

    2015-03-01

    Full Text Available In this study, the optimization of mechanical and damping capacities of Mg-0.6 wt.% Zr alloys by controlling the recrystallized (DRXed grain size under varying extrusion processing parameters including extrusion temperature T and strain rate ε˙ was investigated. The relationship between the DRXed grain size and damping properties of the studied alloy was also discussed. The DRXed grain size of the as-extruded Mg–Zr alloys decreased as the extrusion temperature T decreased and the strain rate ε˙ increased. As the DRXed grain size decreased, the strength and elongation of the as-extruded alloys exhibited improved performance through the grain refinement mechanism, while the damping properties deteriorated. The extrusion temperature of the Mg–Zr alloy had relatively greater effects on the mechanical and damping properties than the strain rate. The results of the present work indicate that alloys with appropriate mechanical and damping properties may be obtained from controlling the DRXed grain size by careful tailoring of the extrusion process parameters.

  8. Influence of processing variables on the mechanical behavior of HDPE/clay nanocomposites

    Directory of Open Access Journals (Sweden)

    Renata Barbosa

    2012-06-01

    Full Text Available Nanocomposites were processed using the technique of melt intercalation, starting from a concentrated polar compatibilizer/organoclay (PE-g-MA/organoclay prepared in an internal mixer. The concentrate was incorporated into the matrix of HDPE by two methods: I counter-rotating twin-screw extruder and II co-rotating twin-screw extruder, using two screw profiles (ROS and 2KB90. After extrusion, the specimens of the extruded composites were injection molded. The X-ray diffraction (XRD technique was used to analyze the degree of expansion of the prepared clays. To analyze the degree of exfoliation of obtained nanocomposites, XRD and TEM (transmission electron microscopy were used. The influence of processing variables on mechanical properties was studied through the behavior of the modulus and tensile strength of nanocomposite systems. By XRD and TEM, it was seen that the clay was well dispersed in the matrix and the presence of intercalated and partially exfoliated hybrid structure for nanocomposites was observed when the systems were prepared in counter-rotating twin-screw extruder. A similar behavior was observed in the use of screws (2KB90 or ROS of the nanocomposites, with a reduction in modulus and tensile strength. Although the mixing process by extruding be the most common industrial practice, and also it is the preferred strategy for the preparation of polymer nanocomposites, much of the literature was directed to the study of chemical modification of clay, type and level of compatibilizer, in order to maximize the compatibility between clay and the polymeric matrix. On the other hand, studies about the role of the processing and configurations of screws are relatively scarce. The main motivation of this work was to expand and to contribute to spread a better understanding of the effects of processing to obtain polymer nanocomposites.

  9. ROLE OF MELT EXTRUSION IN THE ENHANCEMENT OF BIOAVAILABILITY

    Directory of Open Access Journals (Sweden)

    Sahil Bansode* and S. S. Poddar

    2012-11-01

    Full Text Available Starting from plastic industry, today melt extrusion has found its place in the array of pharmaceutical manufacturing processes. Melt extrusion processes are currently applied in the pharmaceutical field for the formulation of variety of dosage forms such as granules, pellets, tablets, implants, transdermal systems & ophthalmic inserts. This technology represents an efficient pathway for increasing the solubility of poorly soluble drugs. The process forms a solid dispersion where the drug is presented in an amorphous & molecularly dispersed state in a carrier. This leads to an increase in solubility, as no lattice energy has to be overcome during dissolution. Melt extrusion is considered to be an efficient technology in the field of formulation of solid dispersions to improve bioavailability with particular advantages over solvent processes. This article highlights on the technology of Hot Melt Extrusion (HME.

  10. The friction in rod forward and backward micro extrusion

    Directory of Open Access Journals (Sweden)

    J. Piwnik

    2010-01-01

    Full Text Available Micro parts are increasingly applied in industry because of the trend to miniaturization every day devices. Microforming is a method of manufacturing metal micro elements using a plastic treatment. This kind of production ensures high productivity, shapes and dimensions repeatability and good surface quality. Size effect connected with small dimensions affects changes in treatment processes of micro parts. While forming in micro scale, surface roughness is size independent and does not decrease with decreasing detail dimensions. The article presents schemas for forward and backward extrusion of metal rods. Using FEM, tool’s roughness as a triangle wave has been assumed, taking into account thereby size effect. Influence of roughness on extrusion forces by comparison with traditional flat tools and constant friction shear factor m has been specified. Impact of roughness caused growth of extrusion forces while forward extruding. On the contrary, backward extrusion ensured stable required forces, regardless of a surface structure.

  11. CHARACTERIZATION OF NEW TOOL STEEL FOR ALUMINUM EXTRUSION DIES

    Directory of Open Access Journals (Sweden)

    José Britti Bacalhau

    2014-06-01

    Full Text Available Aluminum extrusion dies are an important segment of application on industrial tools steels, which are manufactured in steels based on AISI H13 steel. The main properties of steels applied to extrusion dies are: wear resistance, impact resistance and tempering resistance. The present work discusses the characteristics of a newly developed hot work steel to be used on aluminum extrusion dies. The effects of Cr and Mo contents with respect to tempering resistance and the Al addition on the nitriding response have been evaluated. From forged steel bars, Charpy impact test and characterization via EPMA have been conducted. The proposed contents of Cr, Mo, and Al have attributed to the new VEX grade a much better tempering resistance than H13, as well as a deeper and harder nitrided layer. Due to the unique characteristics, this new steel provides an interesting alternative to the aluminum extrusion companies to increase their competitiveness.

  12. Applications of polymer extrusion technology to coal processing

    Science.gov (United States)

    Lewis, D. W.

    1981-01-01

    Upon heating, many of the middle-aged bituminous coals exhibit a plasticity very similar to polyethylene for a few minutes. Plastic coal can be extruded, pelletized or molded using common plastics technology and equipment. Investigations concerning the plastic state of coals are conducted with the objective to develop techniques which will make useful commercial applications of this property possible. Experiments which show the characteristics of plastic-state coal are discussed, and problems related to a continuous extrusion of coal are considered. Probably the most significant difference between the continuous extrusion of coal and the extrusion of a thermoplastic polymer is that volatiles are continuously being released from the coal. Attention is given to aspects of dragflow, solids feeding, and melt pumping. Application potentials for plastic coal extrusion might be related to coal gasification, direct liquefaction, and coal combustion.

  13. A new dual-plate slipometer for measuring slip between molten polymers and extrusion die materials.

    Science.gov (United States)

    Schmalzer, A M; Giacomin, A J

    2014-04-01

    In this work, we study the slip behaviors common to plastics die extrusion metals or platings using a new instrument called a dual-plate slipometer. By dual-plate, we mean that whereas the stationary plate incorporates a local shear stress transducer, the moving plate does not. The stationary plate and transducer are made of one stainless steel, but the moving plate is made from, or plated with, different extrusion die materials under study. This new instrument allows slip velocity to be measured without having to build a new shear stress transducer from each extrusion metal or plating under study. We explore the effect of extrusion die composition and die metal surface morphology on the slip properties of polyolefins using a sliding plate rheometer. In this work, we studied the slip behaviors of polyolefins on four common plastics die extrusion metals or platings, without having to build a new shear stress transducer from each. Specifically, our new method replaces the moving plate; with each of the four die metals or platings under study without changing the stainless steel material of the shear stress transducer and its stationary plate. Our experiments include high-density polyethylene, low-density polyethylene, and polypropylene (PP) on four different die metals or platings. We use steady simple shear to obtain shear stress versus nominal shear rate for different gaps, from which we can then deduce the slip velocity using the Mooney analysis. We then fit four slip models to our experimental measurements, and we find the Hatzikiriakos hyperbolic sine model to be accurate, even for the measured inflections in the slip velocity as a function of shear stress curves. Our analysis includes detailed characterization of the die metal plating surfaces, including measurements of the composition of the sliding plates by energy dispersive spectroscopy, surface energy by contact angle goniometry, and surface roughness by both white light interference and stylus

  14. Obtaining Ready-to-Eat Blue Corn Expanded Snacks with Anthocyanins Using an Extrusion Process and Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Anayansi Escalante-Aburto

    2014-12-01

    Full Text Available Extrusion is an alternative technology for the production of nixtamalized products. The aim of this study was to obtain an expanded nixtamalized snack with whole blue corn and using the extrusion process, to preserve the highest possible total anthocyanin content, intense blue/purple coloration (color b and the highest expansion index. A central composite experimental design was used. The extrusion process factors were: feed moisture (FM, 15%–23%, calcium hydroxide concentration (CHC, 0%–0.25% and final extruder temperature (T, 110–150 °C. The chemical and physical properties evaluated in the extrudates were moisture content (MC, %, total anthocyanins (TA, mg·kg−1, pH, color (L, a, b and expansion index (EI. ANOVA and surface response methodology were applied to evaluate the effects of the extrusion factors. FM and T significantly affected the response variables. An optimization step was performed by overlaying three contour plots to predict the best combination region. The extrudates were obtained under the following optimum factors: FM (% = 16.94, CHC (% = 0.095 and T (°C = 141.89. The predicted extrusion processing factors were highly accurate, yielding an expanded nixtamalized snack with 158.87 mg·kg−1 TA (estimated: 160 mg·kg−1, an EI of 3.19 (estimated: 2.66, and color parameter b of −0.44 (estimated: 0.10.

  15. Effects of raw material extrusion and steam conditioning on feed pellet quality and nutrient digestibility of growing meat rabbits

    Directory of Open Access Journals (Sweden)

    Kuoyao Liao

    2017-06-01

    Full Text Available This study was conducted to investigate the effects of raw material extrusion and steam conditioning on feed pellet quality and nutrient digestibility of growing meat rabbits, in order to determine appropriate rabbit feed processing methods and processing parameters. In Exp. 1, an orthogonal design was adopted. Barrel temperature, material moisture content and feed rate were selected as test factors, and acid detergent fiber (ADF content was selected as an evaluation index to research the optimum extrusion parameters. In Exp. 2, a two-factor design was adopted. Four kinds of rabbit feeds were processed and raw material extrusion adopted optimum extrusion parameters of Exp. 1. A total of 40 healthy and 42-day-old rabbits with similar weight were used in a randomized design, which consisted of 4 groups and 10 replicates in each group (1 rabbits in each replicate. The adaptation period lasted for 7 d, and the digestion trial lasted for 4 d. The results showed as follows: 1 ADF was significantly affected by barrel temperature (P < 0.05; the optimum extrusion parameters were barrel temperature 125 °C, moisture content 16% and feed rate 9 Hz. 2 Raw material extrusion and steam conditioning both significantly decreased powder percentage, pulverization ratio and protein solubility (P < 0.05, significantly improved hardness and starch gelatinization degree of rabbit feed (P < 0.05. They both had significant interaction effects on the processing quality of rabbit feed (P < 0.05. 3 Extrusion significantly improved the apparent digestibility of dry matter and total energy (P < 0.05. Extrusion and steam conditioning both significantly improved the apparent digestibility of crude fiber (CF, ADF and NDF (P < 0.05, but they had no interaction effects on the apparent digestibility of rabbit feed. Thus, using extrusion and steam conditioning technology at the same time in the weaning rabbits feed processing can improve the pellet quality and

  16. Extrusion and properties of lead zirconate titanate piezoelectric ceramics

    DEFF Research Database (Denmark)

    Cai, S.; Millar, C.E.; Pedersen, L.

    1997-01-01

    The purpose of this work was to develop a procedure for fabricating electroceramic actuators with good piezoelectric properties. The preparation of lead zirconate titanate (PZT) piezoelectric ceramic rods and tubes by extrusion processing is described. The microstructure of extrudates was investi......The purpose of this work was to develop a procedure for fabricating electroceramic actuators with good piezoelectric properties. The preparation of lead zirconate titanate (PZT) piezoelectric ceramic rods and tubes by extrusion processing is described. The microstructure of extrudates...

  17. Making Ceramic/Polymer Parts By Extrusion Stereolithography

    Science.gov (United States)

    Stuffle, Kevin; Mulligan, A.; Creegan, P.; Boulton, J. M.; Lombardi, J. L.; Calvert, P. D.

    1996-01-01

    Extrusion stereolithography developmental method of computer-controlled manufacturing of objects out of ceramic/polymer composite materials. Computer-aided design/computer-aided manufacturing (CAD/CAM) software used to create image of desired part and translate image into motion commands for combination of mechanisms moving resin dispenser. Extrusion performed in coordination with motion of dispenser so buildup of extruded material takes on size and shape of desired part. Part thermally cured after deposition.

  18. Sheets of branched poly(lactic acid obtained by one step reactive extrusion calendering process: Melt rheology analysis

    Directory of Open Access Journals (Sweden)

    J. Cailloux

    2013-03-01

    Full Text Available One-step reactive extrusion-calendering process (REX-Calendering was used in order to obtain sheets of 1mm from two PD,L-LA extrusion grades modified with a styrene-acrylic multifunctional oligomeric agent. In a preliminary internal mixer study, torque versus time was monitored in order to determine chain extender ratios and reaction time. Once all parameters were optimized, reactive extrusion experiments were performed. Independently of the processing method employed, under the same processing conditions, PD,L-LA with the lower D enantiomer molar content revealed a higher reactivity towards the reactive agent, induced by its higher thermal sensitivity. REXCalendering process seemed to minimize the degradations reactions during processing, although a competition between degradation and chain extension/branching reactions took place in both processes. Finally, the rheological characterization revealed a higher degree of modification in the melt rheological behaviour for REX-Calendered samples.

  19. Homogenization and texture development in rapidly solidified AZ91E consolidated by Shear Assisted Processing and Extrusion (ShAPE)

    Energy Technology Data Exchange (ETDEWEB)

    Overman, N. R.; Whalen, S. A.; Bowden, M. E.; Olszta, M. J.; Kruska, K.; Clark, T.; Stevens, E. L.; Darsell, J. T.; Joshi, V. V.; Jiang, X.; Mattlin, K. F.; Mathaudhu, S. N.

    2017-07-01

    Shear Assisted Processing and Extrusion (ShAPE) -a novel processing route that combines high shear and extrusion conditions- was evaluated as a processing method to densify melt spun magnesium alloy (AZ91E) flake materials. This study illustrates the microstructural regimes and transitions in crystallographic texture that occur as a result of applying simultaneous linear and rotational shear during extrusion. Characterization of the flake precursor and extruded tube was performed using scanning and transmission electron microscopy, x-ray diffraction and microindentation techniques. Results show a unique transition in the orientation of basal texture development. Despite the high temperatures involved during processing, uniform grain refinement and material homogenization are observed. These results forecast the ability to implement the ShAPE processing approach for a broader range of materials with novel microstructures and high performance.

  20. Formation mechanism of external finned tubes by extrusion-plough method

    Institute of Scientific and Technical Information of China (English)

    TANG Yong; LU Long-sheng; PAN Min-qing; LIU Xiao-kang; LIU Xiao-qing

    2006-01-01

    The formation mechanism of bulge on the work's surface during the extrusion process was analyzed. The bulge's size and the reasons for abscission were studied. The results show that the abscission of bulge from works is resulted from the integrated actions of pressure and friction between the plough tool and works. During the extrusion-plough process, it is noticed that four kinds of fins are appeared, which are gestation fin, multi-dimensional fin, tumor and overlap fin, when using different machining parameters. And multi-dimensional fin which has high heat transmission efficiency is a kind of complicated fin with cockscomb-like 3D substructure fin on the tip of 3D macrostructure fin. Based on the studies of those four kinds of fins, the conditions of their formation are concluded, as well as the formation mechanism is obtained.