In Situ Salt Formation during Melt Extrusion for Improved Chemical Stability and Dissolution Performance of a Meloxicam-Copovidone Amorphous Solid Dispersion.

PubMed

Haser, Abbe; Cao, Tu; Lubach, Joseph W; Zhang, Feng

2018-03-05

As the pipeline for poorly soluble compounds continues to grow, drug degradation during melt extrusion must be addressed. We present a novel method for stabilizing a thermally labile drug substance while preserving its physical stability and even improving its dissolution performance. In a previous study, we found that incorporating meglumine during extrusion of meloxicam results in chemical stabilization that cannot be achieved using process optimization alone. The purpose of this study is to understand the mechanism behind this stabilization and its impact on the performance of a meloxicam-Kollidon VA64 amorphous solid dispersion. The meloxicam concentration was maintained at 10% (w/w) for blends with and without meglumine. The optimal meglumine blend contained an equimolar amount of meloxicam to meglumine with the remainder consisting of Kollidon VA64. Both formulations were processed with optimized extrusion conditions and analyzed by HPLC for purity. Meglumine at a 1:1 molar ratio with meloxicam results in 100% purity of meloxicam after melt extrusion. Solid-state NMR revealed a proton transfer between the meloxicam and meglumine indicating an in situ salt formation. During non-sink dissolution, the meglumine ASD enables meloxicam to maintain supersaturatation (≅50 times more than meloxicam free acid) for >7.25 h. The ASD without meglumine began precipitating 2.25 h following the pH shift. The ASDs were placed at 40 °C/75% RH for 6 months, and their stability was assessed. No significant chemical degradation, recrystallization, or significant moisture uptake was observed after six months' storage at 40 °C/75% RH.

Extrusion and Extruded Products: Changes in Quality Attributes as Affected by Extrusion Process Parameters: A Review.

PubMed

Alam, M S; Kaur, Jasmeen; Khaira, Harjot; Gupta, Kalika

2016-01-01

Extrusion of foods is an emerging technology for the food industries to process and market a large number of products of varying size, shape, texture, and taste. Extrusion cooking technology has led to production of wide variety of products like pasta, breakfast cereals, bread crumbs, biscuits, crackers, croutons, baby foods, snack foods, confectionery items, chewing gum, texturized vegetable protein (TVP), modified starch, pet foods, dried soups, dry beverage mixes etc. The functional properties of extruded foods plays an important role for their acceptability which include water absorption, water solubility, oil absorption indexes, expansion index, bulk density and viscosity of the dough. The aim of this review is to give the detailed outlines about the potential of extrusion technology in development of different types of products and the role of extrusion-operating conditions and their effect on product development resulting in quality changes i.e physical, chemical, and nutritional, experienced during the extrusion process.

How extrusion shapes food processing

USDA-ARS?s Scientific Manuscript database

This month's column will explore food extrusion. Extrusion is one of the most commonly used food manufacturing processes. Its versatility enables production of a diverse array of food products. This column will review the basic principles and provide an overview of applications. I would like to ...

Zr Extrusion – Direct Input for Models & Validation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cerreta, Ellen Kathleen

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

Application of hot melt extrusion for poorly water-soluble drugs: limitations, advances and future prospects.

PubMed

Lu, Ming; Guo, Zhefei; Li, Yongcheng; Pang, Huishi; Lin, Ling; Liu, Xu; Pan, Xin; Wu, Chuanbin

2014-01-01

Hot melt extrusion (HME) is a powerful technology to enhance the solubility and bioavailability of poorly water-soluble drugs by producing amorphous solid dispersions. Although the number of articles and patents about HME increased dramatically in the past twenty years, there are very few commercial products by far. The three main obstacles limiting the commercial application of HME are summarized as thermal degradation of heat-sensitive drugs at high process temperature, recrystallization of amorphous drugs during storage and dissolving process, and difficulty to obtain products with reproducible physicochemical properties. Many efforts have been taken in recent years to understand the basic mechanism underlying these obstacles and then to overcome them. This article reviewed and summarized the limitations, recent advances, and future prospects of HME.

Two-sided friction stir riveting by extrusion: A process for joining dissimilar materials

DOE PAGES

Evans, William T.; Cox, Chase D.; Strauss, Alvin M.; ...

2016-06-25

Two-sided friction stir riveting (FSR) by extrusion is an innovative process developed to rapidly, efficiently, and securely join dissimilar materials. This process extends a previously developed one sided friction stir extrusion process to create a strong and robust joint by producing a continuous, rivet-like structure through a preformed hole in one of the materials with a simultaneous, two-sided friction stir spot weld. The two-sided FSR by extrusion process securely joins the dissimilar materials together and effectively locks them in place without the use of any separate materials or fasteners. Lastly, in this paper we demonstrate the process by joining aluminummore » to steel and illustrate its potential application to automotive and aerospace manufacturing processes.« less

Extrusion cooking: Legume pulses

USDA-ARS?s Scientific Manuscript database

Extrusion is used commercially to produce high value breakfast and snack foods based on cereals such as wheat or corn. However, this processing method is not being commercially used for legume pulses seeds due to the perception that they do not expand well in extrusion. Extrusion cooking of pulses (...

Numerical investigations on the lateral angular co-extrusion of aluminium and steel

NASA Astrophysics Data System (ADS)

Behrens, B.-A.; Klose, C.; Chugreev, A.; Thürer, S. E.; Uhe, J.

2018-05-01

In order to save weight and costs, different materials can be combined within one component. In the novel process chain being developed within the Collaborative Research Centre (CRC) 1153, joined semi-finished workpieces are used to produce hybrid solid components with locally adapted properties. Different materials are joined in an initial step before the forming process takes place. Hereby, the quality of the joining zone is improved by means of the thermo-mechanical treatment during the forming and machining processes. The lateral angular co-extrusion (LACE) approach is used to produce semi-finished workpieces because it allows for the production of coaxial semi-finished products consisting of aluminium and steel. In the further process chain, these semi-finished products are processed into hybrid bearing bushings with locally adapted properties by die forging. In the scope of this work, numerical investigations of the co-extrusion of aluminium-steel compounds were carried out using finite element (FE) simulation in order to examine the influence of the process parameters on the co-extrusion process. For this purpose, the relevant material properties of the aluminium alloy EN AW-6082 were determined experimentally and subsequently implemented in the numerical model. The obtained numerical model was used to study the impact of different ram speeds, press ratios and billet temperatures on the resulting extrusion forces and the material flow. The numerical results have been validated using force-time curves obtained from experimental extrusion tests carried out on a 2.5 MN laboratory extrusion press.

The Effects of Polymer Carrier, Hot Melt Extrusion Process and Downstream Processing Parameters on the Moisture Sorption Properties of Amorphous Solid Dispersions

PubMed Central

Feng, Xin; Vo, Anh; Patil, Hemlata; Tiwari, Roshan V.; Alshetaili, Abdullah S.; Pimparade, Manjeet B.; Repka, Michael A.

2017-01-01

Objective The aim of this study was to evaluate the effect of polymer carrier, hot melt extrusion (HME) and downstream processing parameters on the water uptake properties of amorphous solid dispersions. Methods Three polymers and a model drug were used to prepare amorphous solid dispersions utilizing HME technology. The sorption-desorption isotherms of solid dispersions and their physical mixtures were measured by the Dynamic Vapor Sorption system, and the effect of polymer hydrophobicity, hygroscopicity, molecular weight and the HME process were investigated. FTIR imaging was performed to understand the phase separation driven by the moisture. Key findings Solid dispersions with polymeric carriers with lower hydrophilicity, hygroscopicity, and higher molecular weight could sorb less moisture under the high RH conditions. The water uptake ability of polymer-drug solid dispersion systems were decreased compared to the physical mixture after HME, which might be due to the decreased surface area and porosity. The FTIR imaging indicated the homogeneity of the drug molecularly dispersed within the polymer matrix was changed after exposure to high RH. Conclusion Understanding the effect of formulation and processing on the moisture sorption properties of solid dispersions is essential for the development of drug products with desired physical and chemical stability. PMID:26589107

Formulation and Characterization of Solid Dispersion Prepared by Hot Melt Mixing: A Fast Screening Approach for Polymer Selection

PubMed Central

Enose, Arno A.; Dasan, Priya K.; Sivaramakrishnan, H.; Shah, Sanket M.

2014-01-01

Solid dispersion is molecular dispersion of drug in a polymer matrix which leads to improved solubility and hence better bioavailability. Solvent evaporation technique was employed to prepare films of different combinations of polymers, plasticizer, and a modal drug sulindac to narrow down on a few polymer-plasticizer-sulindac combinations. The sulindac-polymer-plasticizer combination that was stable with good film forming properties was processed by hot melt mixing, a technique close to hot melt extrusion, to predict its behavior in a hot melt extrusion process. Hot melt mixing is not a substitute to hot melt extrusion but is an aid in predicting the formation of molecularly dispersed form of a given set of drug-polymer-plasticizer combination in a hot melt extrusion process. The formulations were characterized by advanced techniques like optical microscopy, differential scanning calorimetry, hot stage microscopy, dynamic vapor sorption, and X-ray diffraction. Subsequently, the best drug-polymer-plasticizer combination obtained by hot melt mixing was subjected to hot melt extrusion process to validate the usefulness of hot melt mixing as a predictive tool in hot melt extrusion process. PMID:26556187

Pharmaceutical approaches to preparing pelletized dosage forms using the extrusion-spheronization process.

PubMed

Trivedi, Namrata R; Rajan, Maria Gerald; Johnson, James R; Shukla, Atul J

2007-01-01

Pelletized dosage forms date back to the 1950s, when the first product was introduced to the market. Since then, these dosage forms have gained considerable popularity because of their distinct advantages, such as ease of capsule filling because of better flow properties of the spherical pellets; enhancement of drug dissolution; ease of coating; sustained, controlled, or site-specific delivery of the drug from coated pellets; uniform packing; even distribution in the GI tract; and less GI irritation. Pelletized dosage forms can be prepared by a number of techniques, including drug layering on nonpareil sugar or microcrystalline cellulose beads, spray drying, spray congealing, rotogranulation, hot-melt extrusion, and spheronization of low melting materials or extrusion-spheronization of a wet mass. This review discusses recent developments in the pharmaceutical approaches that have been used to prepare pelletized dosage forms using the extrusion-spheronization process over the last decade. The review is divided into three parts: the first part discusses the extrusion-spheronization process, the second part discusses the effect of varying formulation and process parameters on the properties of the pellets, and the last part discusses the different approaches that have been used to prepare pelletized dosage forms using the extrusion-spheronization process.

Hot-melt co-extrusion: requirements, challenges and opportunities for pharmaceutical applications.

PubMed

Vynckier, An-Katrien; Dierickx, Lien; Voorspoels, Jody; Gonnissen, Yves; Remon, Jean Paul; Vervaet, Chris

2014-02-01

Co-extrusion implies the simultaneous hot-melt extrusion of two or more materials through the same die, creating a multi-layered extrudate. It is an innovative continuous production technology that offers numerous advantages over traditional pharmaceutical processing techniques. This review provides an overview of the co-extrusion equipment, material requirements and medical and pharmaceutical applications. The co-extrusion equipment needed for pharmaceutical production has been summarized. Because the geometrical design of the die dictates the shape of the final product, different die types have been discussed. As one of the major challenges at the moment is shaping the final product in a continuous way, an overview of downstream solutions for processing co-extrudates into drug products is provided. Layer adhesion, extrusion temperature and viscosity matching are pointed out as most important requirements for material selection. Examples of medical and pharmaceutical applications are presented and some recent findings considering the production of oral drug delivery systems have been summarized. Co-extrusion provides great potential for the continuous production of fixed-dose combination products which are gaining importance in pharmaceutical industry. There are still some barriers to the implementation of co-extrusion in the pharmaceutical industry. The optimization of downstream processing remains a point of attention. © 2013 Royal Pharmaceutical Society.

Implementation of transmission NIR as a PAT tool for monitoring drug transformation during HME processing.

PubMed

Islam, Muhammad T; Scoutaris, Nikolaos; Maniruzzaman, Mohammed; Moradiya, Hiren G; Halsey, Sheelagh A; Bradley, Michael S A; Chowdhry, Babur Z; Snowden, Martin J; Douroumis, Dennis

2015-10-01

The aim of the work reported herein was to implement process analytical technology (PAT) tools during hot melt extrusion (HME) in order to obtain a better understanding of the relationship between HME processing parameters and the extruded formulations. For the first time two in-line NIR probes (transmission and reflectance) have been coupled with HME to monitor the extrusion of the water insoluble drug indomethacin (IND) in the presence of Soluplus (SOL) or Kollidon VA64 hydrophilic polymers. In-line extrusion monitoring of sheets, produced via a specially designed die, was conducted at various drug/polymer ratios and processing parameters. Characterisation of the extruded transparent sheets was also undertaken by using DSC, XRPD and Raman mapping. Analysis of the experimental findings revealed the production of molecular solutions where IND is homogeneously blended (ascertained by Raman mapping) in the polymer matrices, as it acts as a plasticizer for both hydrophilic polymers. PCA analysis of the recorded NIR signals showed that the screw speed used in HME affects the recorded spectra but not the homogeneity of the embedded drug in the polymer sheets. The IND/VA64 and IND/SOL extruded sheets displayed rapid dissolution rates with 80% and 30% of the IND being released, respectively within the first 20min. Copyright © 2015 Elsevier B.V. All rights reserved.

Numerical investigation of the effect of friction conditions to increase die life

NASA Astrophysics Data System (ADS)

Mutlu, M. O.; Guleryuz, C. G.; Parlar, Z.

2017-02-01

The standard die materials in aluminium extrusion offer good mechanical properties like high tempering resistance, high strength and ductility. On the other hand, they struggle with the problem of sliding wear. As a result, there is a growing interest in using surface treatment techniques to increase the wear resistance of extrusion dies. In this study, it is aimed to observe the effects of the different friction conditions on material flow and contact pressure in extrusion process. These friction conditions can be obtained with the application of a variety of surface treatment. In this way, it is expected to decrease the friction force on the die bearing area and to increase the homogeneity of the material flow which will result in the increase of the quality of the extrudate as well as the improvement of the process economically by extending die life. For this purpose, an extrusion process is simulated with a finite element software. A die made of 1.2344 hot work tool steel-commonly used die material for aluminium extrusion process- has been modelled and Al 1100 alloy used as billet material. Various friction factor values defined on the die surface under the same process parameters and effects of changing frictional conditions on the die and the extrusion process have been discussed.

Sacrificial component fabrication for optimised production of micro-vascular polymer composite

NASA Astrophysics Data System (ADS)

Dalton, B.; Dixon, D.; McIlhagger, A.; Archer, E.

2015-02-01

Smart functional materials are a viable future goal for advanced applications in aerospace, space and medical applications. In this work micro-vascular polymer composite systems have been developed using sacrificial fibres produced from catalyst loaded Poly(lactic acid). The sacrificial fibres have been produced via a published technique which treated PLA in a solvent catalyst mixture of 60% Trifluoroethanol, 40% H2O dispersed with 10 wt% tin (II) oxalate catalyst. A second process of polymer extrusion of PLA using graded fill contents of tin (II) oxalate has also been developed for the up scaled production of fibres as an alternative to solution treatment. Thermal analysis (TGA) was used to compare sacrificial fibre specimens. PLA fibres produced via the polymer extrusion method outperformed solution treated fibres displaying a lower degradation onset temperature (average 25°C lower), higher degradation rates (observed through a derivative curve comparison) and lower residual catalyst content (0.67% solvent treated fibre against 0.16% extruded fibre). The continuous extrusion process is solvent free and is suitable for high volume production. This work has been carried out to fully understand the fabrication issues with sacrificial components.

Computer aided design of extrusion forming tools for complex geometry profiles

NASA Astrophysics Data System (ADS)

Goncalves, Nelson Daniel Ferreira

In the profile extrusion, the experience of the die designer is crucial for obtaining good results. In industry, it is quite usual the need of several experimental trials for a specific extrusion die before a balanced flow distribution is obtained. This experimental based trial-and-error procedure is time and money consuming, but, it works, and most of the profile extrusion companies rely on such method. However, the competition is forcing the industry to look for more effective procedures and the design of profile extrusion dies is not an exception. For this purpose, computer aided design seems to be a good route. Nowadays, the available computational rheology numerical codes allow the simulation of complex fluid flows. This permits the die designer to evaluate and to optimize the flow channel, without the need to have a physical die and to perform real extrusion trials. In this work, a finite volume based numerical code was developed, for the simulation of non-Newtonian (inelastic) fluid and non-isothermal flows using unstructured meshes. The developed code is able to model the forming and cooling stages of profile extrusion, and can be used to aid the design of forming tools used in the production of complex profiles. For the code verification three benchmark problems were tested: flow between parallel plates, flow around a cylinder, and the lid driven cavity flow. The code was employed to design two extrusion dies to produce complex cross section profiles: a medical catheter die and a wood plastic composite profile for decking applications. The last was experimentally validated. Simple extrusion dies used to produced L and T shaped profiles were studied in detail, allowing a better understanding of the effect of the main geometry parameters on the flow distribution. To model the cooling stage a new implicit formulation was devised, which allowed the achievement of better convergence rates and thus the reduction of the computation times. Having in mind the solution of large dimension problems, the code was parallelized using graphics processing units (GPUs). Speedups of ten times could be obtained, drastically decreasing the time required to obtain results.

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

NASA Astrophysics Data System (ADS)

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 solvents). Finally, the surface topographies of melt processed poly(L-lactic acid) (ranging from nanoindentations to spherulitic protrusions) were determined to affect the orientation directions of fibroblast and osteoblast-like cells and the spherulitic surfaces giving rise to reduced proliferation rates of fibroblasts.

Topological defects in epithelia govern cell death and extrusion

NASA Astrophysics Data System (ADS)

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 extrusion hotspots and dynamics in vivo, with potential applications to tissue regeneration and the suppression of metastasis. Moreover, we anticipate that the analogy between the epithelium and active nematic liquid crystals will trigger further investigations of the link between cellular processes and the material properties of epithelia.

Processing thermally labile drugs by hot-melt extrusion: The lesson with gliclazide.

PubMed

Huang, Siyuan; O'Donnell, Kevin P; Delpon de Vaux, Sophie M; O'Brien, John; Stutzman, John; Williams, Robert O

2017-10-01

The formation of molecularly dispersed amorphous solid dispersions by the hot-melt extrusion technique relies on the thermal and mechanical energy inputs, which can cause chemical degradation of drugs and polymeric carriers. Additionally, drug degradation may be exacerbated as drugs convert from a more stable crystalline form to a higher energy amorphous form. Therefore, it is imperative to study how drug degrades and evaluate methods to minimize drug degradation during the extrusion process. In this work, gliclazide was used as a model thermally labile drug for the degradation kinetics and process optimization studies. Preformulation studies were conducted using thermal analyses, and liquid chromatography-mass spectroscopy to identify drug degradation pathways and to determine initial extrusion conditions. Formulations containing 10% drug and 90% AFFINISOL™ HPMC HME 100LV were then extruded using a twin screw extruder, and the extrudates were characterized using X-ray powder diffraction, modulated dynamic scanning calorimetry, and potency testing to evaluate physicochemical properties. The energies of activation for both amorphous gliclazide, crystalline gliclazide, and gliclazide solution were calculated using the Arrhenius equation to further guide the extrusion optimization process. Preformulation studies identify two hydrolysis degradation pathways of gliclazide at elevated temperatures. The activation energy study indicates a significantly higher degradation rate for the amorphous gliclazide compared to the crystalline form. After optimization of the hot-melt extrusion process, including improved screw designs, machine setup, and processing conditions, gliclazide amorphous solid dispersion with ∼95% drug recovery was achieved. The ability to process thermally labile drugs and polymers using hot-melt extrusion will significantly expand the possible applications of this manufacturing process. Copyright © 2017 Elsevier B.V. All rights reserved.

Extrusion Processing of Raw Food Materials and by-products: A Review.

PubMed

Offiah, Vivian; Kontogiorgos, Vassilis; Falade, Kolawole O

2018-05-22

Extrusion technology has rapidly transformed the food industry with its numerous advantages over other processing methods. It offers a platform for processing different products from various food groups by modifying minor or major ingredients and processing conditions. Although cereals occupy a large portion of the extruded foods market, several other types of raw materials have been used. Extrusion processing of various food groups, including cereals and pseudo cereals, roots and tubers, pulses and oilseeds, fruits and vegetables, and animal products, as well as structural and nutritional changes in these food matrices are reviewed. Value addition by extrusion to food processing wastes and by-products from fruits and vegetables, dairy, meat and seafood, cereals and residues from starch, syrup and alcohol production, and oilseed processing are also discussed. Extrusion presents an economical technology for incorporating food processing residues and by-products back into the food stream. In contemporary scenarios, rising demand for extruded products with functional ingredients, attributed to evolving lifestyles and preferences, have led to innovations in the form, texture, color and content of extruded products. Information presented in this review would be of importance to processors and researchers as they seek to enhance nutritional quality and delivery of extruded products.

Recapturing Graphite-Based Fuel Element Technology for Nuclear Thermal Propulsion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trammell, Michael P; Jolly, Brian C; Miller, James Henry

ORNL is currently recapturing graphite based fuel forms for Nuclear Thermal Propulsion (NTP). This effort involves research and development on materials selection, extrusion, and coating processes to produce fuel elements representative of historical ROVER and NERVA fuel. Initially, lab scale specimens were fabricated using surrogate oxides to develop processing parameters that could be applied to full length NTP fuel elements. Progress toward understanding the effect of these processing parameters on surrogate fuel microstructure is presented.

Procyanidin content of grape seed and pomace, and total anthocyanin content of grape pomace as affected by extrusion processing.

PubMed

Khanal, R C; Howard, L R; Prior, R L

2009-08-01

Grape juice processing by-products, grape seed and pomace are a rich source of procyanidins, compounds that may afford protection against chronic disease. This study was undertaken to identify optimal extrusion conditions to enhance the contents of monomers and dimers at the expense of large molecular weight procyanidin oligomers and polymers in grape seed and pomace. Extrusion variables, temperature (160, 170, and 180 degrees C in grape seed, and 160, 170, 180, and 190 degrees C in pomace) and screw speed (100, 150, and 200 rpm in both) were tested using mixtures of grape seed as well as pomace with decorticated white sorghum flour at a ratio of 30 : 70 and moisture content of 45%. Samples of grape seed and pomace were analyzed for procyanidin composition before and after extrusion, and total anthocyanins were determined in pomace. Additionally, chromatograms from diol and normal phase high-performance liquid chromatography were compared for the separation of procyanidins. Extrusion of both grape by-products increased the biologically important monomer and dimers considerably across all temperature and screw speeds. Highest monomer content resulted when extruded at a temperature of 170 degrees C and screw speed of 200 rpm, which were 120% and 80% higher than the unextruded grape seed and pomace, respectively. Increases in monomer and dimer contents were apparently the result of reduced polymer contents, which declined by 27% to 54%, or enhanced extraction facilitated by disruption of the food matrix during extrusion. Extrusion processing reduced total anthocyanins in pomace by 18% to 53%. Extrusion processing can be used to increase procyanidin monomer and dimer contents in grape seed and pomace. Procyanidins in grape by-products have many health benefits, but most are present as large molecular weight compounds, which are poorly absorbed. Extrusion processing appears to be a promising technology to increase levels of the bioactive low molecular weight procyanidins.

Effects of raw material extrusion and steam conditioning on feed pellet quality and nutrient digestibility of growing meat rabbits.

PubMed

Liao, Kuoyao; Cai, Jingyi; Shi, Zhujun; Tian, Gang; Yan, Dong; Chen, Delin

2017-06-01

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 nutrient apparent digestibility of rabbit feed.

Effect of extrusion processing on the microstructure, mechanical properties, biocorrosion properties and antibacterial properties of Ti-Cu sintered alloys.

PubMed

Zhang, Erlin; Li, Shengyi; Ren, Jing; Zhang, Lan; Han, Yong

2016-12-01

Ti-Cu sintered alloys, Ti-Cu(S) alloy, have exhibited good anticorrosion resistance and strong antibacterial properties, but low ductility in previous study. In this paper, Ti-Cu(S) alloys were subjected to extrusion processing in order to improve the comprehensive property. The phase constitute, microstructure, mechanical property, biocorrosion property and antibacterial activity of the extruded alloys, Ti-Cu(E), were investigated in comparison with Ti-Cu(S) by X-ray diffraction (XRD), optical microscopy (OM), scanning electronic microscopy (SEM) with energy disperse spectroscopy (EDS), mechanical testing, electrochemical testing and plate-count method in order to reveal the effect of the extrusion process. XRD, OM and SEM results showed that the extrusion process did not change the phase constitute but refined the grain size and Ti2Cu particle significantly. Ti-Cu(E) alloys exhibited higher hardness and compressive yield strength than Ti-Cu(S) alloys due to the fine grain and Ti2Cu particles. With the consideration of the total compressive strain, it was suggested that the extrusion process could improve the ductility of Ti-Cu alloy(S) alloys. Electrochemical results have indicated that the extrusion process improved the corrosion resistance of Ti-Cu(S) alloys. Plate-count method displayed that both Ti-Cu(S) and Ti-Cu(E) exhibited strong antibacterial activity (>99%) against S. aureus. All these results demonstrated that hot forming processing, such as the extrusion in this study, refined the microstructure and densified the alloy, in turn improved the ductility and strength as well as anticorrosion properties without reduction in antibacterial properties. Copyright © 2016 Elsevier B.V. All rights reserved.

Homogenization and texture development in rapidly solidified AZ91E consolidated by Shear Assisted Processing and Extrusion (ShAPE)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Overman, N. R.; Whalen, S. A.; Bowden, M. E.

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 refinementmore » 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.« less

Ultrafine-grained titanium for medical implants

DOEpatents

Zhu, Yuntian T.; Lowe, Terry C.; Valiev, Ruslan Z.; Stolyarov, Vladimir V.; Latysh, Vladimir V.; Raab, Georgy J.

2002-01-01

We disclose ultrafine-grained titanium. A coarse-grained titanium billet is subjected to multiple extrusions through a preheated equal channel angular extrusion (ECAE) die, with billet rotation between subsequent extrusions. The resulting billet is cold processed by cold rolling and/or cold extrusion, with optional annealing. The resulting ultrafine-grained titanium has greatly improved mechanical properties and is used to make medical implants.

Mechanical strength of welding zones produced by material extrusion additive manufacturing.

PubMed

Davis, Chelsea S; Hillgartner, Kaitlyn E; Han, Seung Hoon; Seppala, Jonathan E

2017-08-01

As more manufacturing processes and research institutions adopt customized manufacturing as a key element in their design strategies and finished products, the resulting mechanical properties of parts produced through additive manufacturing (AM) must be characterized and understood. In material extrusion (MatEx), the most recently extruded polymer filament must bond to the previously extruded filament via polymer diffusion to form a "weld". The strength of the weld limits the performance of the manufactured part and is controlled through processing conditions. Under-standing the role of processing conditions, specifically extruder velocity and extruder temperature, on the overall strength of the weld will allow optimization of MatEx-AM parts. Here, the fracture toughness of a single weld is determined through a facile "trouser tear" Mode III fracture experiment. The actual weld thickness is observed directly by optical microscopy characterization of cross sections of MatEx-AM samples. Representative data of weld strength as a function of printing parameters on a commercial 3D printer demonstrates the robustness of the method.

Stability of mycotoxins during food processing.

PubMed

Bullerman, Lloyd B; Bianchini, Andreia

2007-10-20

The mycotoxins that commonly occur in cereal grains and other products are not completely destroyed during food processing operations and can contaminate finished processed foods. The mycotoxins most commonly associated with cereal grains are aflatoxins, ochratoxin A, fumonisins, deoxynivalenol and zearalenone. The various food processes that may have effects on mycotoxins include sorting, trimming, cleaning, milling, brewing, cooking, baking, frying, roasting, canning, flaking, alkaline cooking, nixtamalization, and extrusion. Most of the food processes have variable effects on mycotoxins, with those that utilize the highest temperatures having greatest effects. In general the processes reduce mycotoxin concentrations significantly, but do not eliminate them completely. However, roasting and extrusion processing show promise for lowering mycotoxin concentrations, though very high temperatures are needed to bring about much of a reduction in mycotoxin concentrations. Extrusion processing at temperatures greater than 150 degrees C are needed to give good reduction of zearalenone, moderate reduction of alfatoxins, variable to low reduction of deoxynivalenol and good reduction of fumonisins. The greatest reductions of fumonisins occur at extrusion temperatures of 160 degrees C or higher and in the presence of glucose. Extrusion of fumonisin contaminated corn grits with 10% added glucose resulted in 75-85% reduction in Fumonisin B(1) levels. Some fumonisin degredation products are formed during extrusion, including small amounts of hydrolyzed Fumonisin B(1) and N-(Carboxymethyl) - Fumonisin B(1) and somewhat higher amounts of N-(1-deoxy-d-fructos-1-yl) Fumonisin B(1) in extruded grits containing added glucose. Feeding trial toxicity tests in rats with extruded fumonisin contaminated corn grits show some reduction in toxicity of grits extruded with glucose.

Processing biobased polymers using plasticizers: Numerical simulations versus experiments

NASA Astrophysics Data System (ADS)

Desplentere, Frederik; Cardon, Ludwig; Six, Wim; Erkoç, Mustafa

2016-03-01

In polymer processing, the use of biobased products shows lots of possibilities. Considering biobased materials, biodegradability is in most cases the most important issue. Next to this, bio based materials aimed at durable applications, are gaining interest. Within this research, the influence of plasticizers on the processing of the bio based material is investigated. This work is done for an extrusion grade of PLA, Natureworks PLA 2003D. Extrusion through a slit die equipped with pressure sensors is used to compare the experimental pressure values to numerical simulation results. Additional experimental data (temperature and pressure data along the extrusion screw and die are recorded) is generated on a dr. Collin Lab extruder producing a 25mm diameter tube. All these experimental data is used to indicate the appropriate functioning of the numerical simulation tool Virtual Extrusion Laboratory 6.7 for the simulation of both the industrial available extrusion grade PLA and the compound in which 15% of plasticizer is added. Adding the applied plasticizer, resulted in a 40% lower pressure drop over the extrusion die. The combination of different experiments allowed to fit the numerical simulation results closely to the experimental values. Based on this experience, it is shown that numerical simulations also can be used for modified bio based materials if appropriate material and process data are taken into account.

Present Situation of the Anti-Fatigue Processing of High-Strength Steel Internal Thread Based on Cold Extrusion Technology: A Review

NASA Astrophysics Data System (ADS)

Miao, Hong; Jiang, Cheng; Liu, Sixing; Zhang, Shanwen; Zhang, Yanjun

2017-03-01

The adoption of cold-extrusion forming for internal thread net forming becomes an important component of anti-fatigue processing with the development of internal thread processing towards high performance, low cost and low energy consumption. It has vast application foreground in the field of aviation, spaceflight, high speed train and etc. The internal thread processing and anti-fatigue manufacture technology are summarized. In terms of the perspective of processing quality and fatigue serving life, the advantages and disadvantages of the processing methods from are compared. The internal thread cold-extrusion processing technology is investigated for the purpose of improving the anti-fatigue serving life of internal thread. The superiorities of the plastic deformation law and surface integrity of the metal layer in the course of cold extrusion for improving its stability and economy are summed up. The proposed research forecasts the development tendency of the internal thread anti-fatigue manufacturing technology.

Microstructure evolution and mechanical properties of nano-SiCp/AZ91 composite processed by extrusion and equal channel angular pressing (ECAP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiao, X.G.; Ying, T.

Nano-SiCp/AZ91 magnesium matrix composite was fabricated by stir casting. The as-cast ingots were extruded at 350 °C, then processed by equal channel angular pressing (ECAP) at various temperatures (250 °C, 300 °C and 350 °C). Grains are significantly refined after the extrusion and the ECAP. A basal fibre texture was detected by neutron diffraction after the extrusion, which inclines about 45° to the extrusion direction (ED) after the ECAP. Nano-scaled SiC particles agglomerate in the as-cast composite. After the extrusion, the agglomeration tends to form continuous or discontinuous strips along the extrusion direction. By application of the ECAP, the agglomeratedmore » SiC particles are partly dispersed and the strips formed during the extrusion tend to be thinner and broken with the increasing pass number. The yield tensile strength (YTS) and the ultimate tensile strength (UTS) of the composite are dramatically increased after the extrusion. ECAP for one pass at various temperatures further increases the strength, however, the YTS decreases with the increasing ECAP temperature and the pass number. The Orowan equations predict the maximum YTS of the composite may be up to 400 MPa providing SiC particles are homogenously distributed in the matrix. - Highlights: •Nano-scaled SiC particles were successfully added into AZ91 by stirring casting. •Agglomeration of nano-particles were improved by extrusion and ECAP. •Yield strength of the composite is 328 MPa after one pass of ECAP. •Further ECAP process with optimized parameters may fully disperse nano-particles. •Yield strength is predicted to up to 400 MPa when particles are fully dispersed.« less

Melt Extrusion of High-Dose Co-Amorphous Drug-Drug Combinations : Theme: Formulation and Manufacturing of Solid Dosage Forms Guest Editors: Tony Zhou and Tonglei Li.

PubMed

Arnfast, Lærke; Kamruzzaman, Md; Löbmann, Korbinian; Aho, Johanna; Baldursdottir, Stefania; Rades, Thomas; Rantanen, Jukka

2017-12-01

Many future drug products will be based on innovative manufacturing solutions, which will increase the need for a thorough understanding of the interplay between drug material properties and processability. In this study, hot melt extrusion of a drug-drug mixture with minimal amount of polymeric excipient was investigated. Using indomethacin-cimetidine as a model drug-drug system, processability of physical mixtures with and without 5% (w/w) of polyethylene oxide (PEO) were studied using Differential Scanning Calorimetry (DSC) and Small Amplitude Oscillatory Shear (SAOS) rheometry. Extrudates containing a co-amorphous glass solution were produced and the solid-state composition of these was studied with DSC. Rheological analysis indicated that the studied systems display viscosities higher than expected for small molecule melts and addition of PEO decreased the viscosity of the melt. Extrudates of indomethacin-cimetidine alone displayed amorphous-amorphous phase separation after 4 weeks of storage, whereas no phase separation was observed during the 16 week storage of the indomethacin-cimetidine extrudates containing 5% (w/w) PEO. Melt extrusion of co-amorphous extrudates with low amounts of polymer was found to be a feasible manufacturing technique. Addition of 5% (w/w) polymer reduced melt viscosity and prevented phase separation.

Effects of Hot-Hydrostatic Canned Extrusion on the Stock Utilization, Microstructure and Mechanical Properties of TiBw/TC4 Composites with Quasi-Continuous Network

PubMed Central

Feng, Yangju; Li, Bing; Cui, Guorong; Zhang, Wencong

2017-01-01

In-situ TiB whisker-reinforced Ti–6Al–4V (TC4) titanium matrix composites (TiBw/TC4) with quasi-continuous networks were successfully fabricated by vacuum hot-pressing sintering. The effects of the hot-hydrostatic canned extrusion on stock utilization, microstructure and mechanical properties of the TiBw/TC4 composites were investigated. It was satisfactory that the utilization of composites could be obviously improved by canned extrusion compared to that extruded without canned extrusion. The microstructure results showed that after canned extrusion the grain was refined and the TiB whiskers were distributed from a random array state to a state in which the whiskers were distributed along the extrusion direction. The properties testing results revealed that the tensile strength, the hardness and the ductility of the composites all significantly improved after extrusion due to the grain refinement and orientation of the TiB whisker caused by extrusion. Tensile fracture results showed that when the TiB whiskers were randomly distributed only part of them played a role in strengthening the matrix during the deformation process (as-sintered composites), while when the TiB whiskers were oriented all whiskers could strengthen the matrix during the tensile testing process (as-extruded composites). PMID:29068416

Scaled-Up Fabrication of Thin-Walled ZK60 Tubing using Shear Assisted Processing and Extrusion (ShAPE)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whalen, Scott A.; Joshi, Vineet V.; Overman, Nicole R.

Shear Assisted Processing and Extrusion (ShAPE) has been scaled-up and applied to direct extrusion of thin-walled magnesium tubing. Using ShAPE, billets of ZK60A-T5 were directly extruded into round tubes having an outer diameter of 50.8 mm and wall thickness of 1.52 mm. The severe shearing conditions inherent to ShAPE resulted in microstructural refinement with an average grain size of 3.8μm measured at the midpoint of the tube wall. Tensile testing per ATSM E-8 on specimens oriented parallel to the extrusion direction gave an ultimate tensile strength of 254.4 MPa and elongation of 20.1%. Specimens tested perpendicular to the extrusion directionmore » had an ultimate tensile strength of 297.2 MPa and elongation of 25.0%. Due to material flow effects resulting from the simultaneous linear and rotational shear intrinsic to ShAPE, ram force and electrical power consumption during extrusion were just 40 kN and 11.5 kW respectively. This represents a significant reduction in ram force and power consumption compared to conventional extrusion. As such, there is potential for ShAPE to offer a scalable, lower cost extrusion option with potentially improved bulk mechanical properties.« less

Effects of Hot-Hydrostatic Canned Extrusion on the Stock Utilization, Microstructure and Mechanical Properties of TiBw/TC4 Composites with Quasi-Continuous Network.

PubMed

Feng, Yangju; Li, Bing; Cui, Guorong; Zhang, Wencong

2017-10-25

In-situ TiB whisker-reinforced Ti-6Al-4V (TC4) titanium matrix composites (TiBw/TC4) with quasi-continuous networks were successfully fabricated by vacuum hot-pressing sintering. The effects of the hot-hydrostatic canned extrusion on stock utilization, microstructure and mechanical properties of the TiBw/TC4 composites were investigated. It was satisfactory that the utilization of composites could be obviously improved by canned extrusion compared to that extruded without canned extrusion. The microstructure results showed that after canned extrusion the grain was refined and the TiB whiskers were distributed from a random array state to a state in which the whiskers were distributed along the extrusion direction. The properties testing results revealed that the tensile strength, the hardness and the ductility of the composites all significantly improved after extrusion due to the grain refinement and orientation of the TiB whisker caused by extrusion. Tensile fracture results showed that when the TiB whiskers were randomly distributed only part of them played a role in strengthening the matrix during the deformation process (as-sintered composites), while when the TiB whiskers were oriented all whiskers could strengthen the matrix during the tensile testing process (as-extruded composites).

Effect of extrusion conditions on the physico-chemical properties and in vitro protein digestibility of canola meal.

PubMed

Zhang, Bo; Liu, Guo; Ying, Danyang; Sanguansri, Luz; Augustin, Mary Ann

2017-10-01

Canola meal has potential as a high protein food ingredient. The extrusion-induced changes in color, pH, extractable protein and in vitro protein digestibility of canola meal under different extrusion conditions was assessed. The extrusion barrel moisture (24%, 30% or 36%) and screw kneading block length (0, 30 or 60mm) were used as independent process parameters. Extrusion at high barrel moisture (36%) favored protein aggregation resulting in lower extractable protein compared to extrusion at the lowest barrel moisture (24%). At lower barrel moisture contents (24% and 30%), a longer kneading block length increased extractable protein but this was not the case at 36% barrel moisture. Canola protein digestibility was improved upon extrusion at 30% barrel moisture but there was no significant change at lower (24%) or higher (36%) barrel moisture. The kneading block length of the screw had no significant effect on the canola protein digestibility within the same barrel moisture level. The relationship between the physico-chemical parameters and in vitro digestibility was examined. This study highlighted the complex interplay of extrusion processing variables that affect protein degradation and the interaction of components, with consequent effects on protein digestibility. Copyright © 2017 Elsevier Ltd. All rights reserved.

Calibrator device for the extrusion of cable coatings

NASA Astrophysics Data System (ADS)

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.

The FEM simulation of continuous rotary extrusion (CRE) of aluminum alloy AA3003

NASA Astrophysics Data System (ADS)

Rajendran, Nijenthan; Valberg, Henry; Misiolek, Wojciech Z.

2017-10-01

Continuous Rotary Extrusion (CRE) process is also known in literature under Conform TM name and it is mainly used for the continuous extrusion of Aluminum and Copper alloys. CRE use a feedstock in the form of rod, powders and chips, which are fed into the groove of the rotating wheel. As the wheel rotates the feedstock moves along with it due to friction with the wheel. Once the feedstock reaches the abutment the material deforms plastically and it is extruded through the die. CRE has lot to offer when compared to other more conventional extrusion processes such as low energy input, no limit in billet length as it is a continuous process as well as improved material physical properties due to plastic deformation under constant parameters. In this work a FEM model has been developed using Deform TM 3D, to study the metal flow and state variables of AA3003 CRE extrusion. The effect of extrusion wheel velocity has been investigated. The results show that increase in wheel velocity will heat up the feedstock metal due to high shear deformation and higher friction, which significantly changes metal flow conditions at the die exit.

The microbial fermentation characteristics depend on both carbohydrate source and heat processing: a model experiment with ileo-cannulated pigs.

PubMed

Nielsen, Tina Skau; Jørgensen, Henry; Knudsen, Knud Erik Bach; Lærke, Helle Nygaard

2017-11-01

The effects of carbohydrate (CHO) source and processing (extrusion cooking) on large intestinal fermentation products were studied in ileo-cannulated pigs as a model for humans. Pigs were fed diets containing barley, pea or a mixture of potato starch:wheat bran (PSWB) either raw or extrusion cooked. Extrusion cooking reduced the amount of starch fermented in the large intestine by 52-96% depending on the CHO source and the total pool of butyrate in the distal small intestine + large intestine by on average 60% across diets. Overall, extrusion cooking caused a shift in the composition of short-chain fatty acids (SCFA) produced towards more acetate and less propionate and butyrate. The CHO source and processing highly affected the fermentation characteristics and extrusion cooking generally reduced large intestinal fermentation and resulted in a less desirable composition of the fermentation products. The latter outcome is non-conducive to a healthy large intestinal environment and its resulting metabolic health.

Extrusion Process by Finite Volume Method Using OpenFoam Software

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matos Martins, Marcelo; Tonini Button, Sergio; Divo Bressan, Jose

The computational codes are very important tools to solve engineering problems. In the analysis of metal forming process, such as extrusion, this is not different because the computational codes allow analyzing the process with reduced cost. Traditionally, the Finite Element Method is used to solve solid mechanic problems, however, the Finite Volume Method (FVM) have been gaining force in this field of applications. This paper presents the velocity field and friction coefficient variation results, obtained by numerical simulation using the OpenFoam Software and the FVM to solve an aluminum direct cold extrusion process.

Moisture content during extrusion of oats impacts the initial fermentation metabolites and probiotic bacteria during extended fermentation by human fecal microbiota.

PubMed

Brahma, Sandrayee; Weier, Steven A; Rose, Devin J

2017-07-01

Extrusion exposes flour components to high pressure and shear during processing, which may affect the dietary fiber fermentability by human fecal microbiota. The objective of this study was to determine the effect of flour moisture content during extrusion on in vitro fermentation properties of whole grain oats. Extrudates were processed at three moisture levels (15%, 18%, and 21%) at fixed screw speed (300rpm) and temperature (130°C). The extrudates were then subjected to in vitro digestion and fermentation. Extrusion moisture significantly affected water-extractable β-glucan (WE-BG) in the extrudates, with samples processed at 15% moisture (lowest) and 21% moisture (highest) having the highest concentration of WE-BG. After the first 8h of fermentation, more WE-BG remained in fermentation media in samples processed at 15% moisture compared with the other conditions. Also, extrusion moisture significantly affected the production of acetate, butyrate, and total SCFA by the microbiota during the first 8h of fermentation. Microbiota grown on extrudates processed at 18% moisture had the highest production of acetate and total SCFA, whereas bacteria grown on extrudates processed at 15% and 18% moisture had the highest butyrate production. After 24h of fermentation, samples processed at 15% moisture supported lower Bifidobacterium counts than those produced at other conditions, but had among the highest Lactobacillus counts. Thus, moisture content during extrusion significantly affects production of fermentation metabolites by the gut microbiota during the initial stages of fermentation, while also affecting probiotic bacteria counts during extended fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Weld formation during material extrusion additive manufacturing.

PubMed

Seppala, Jonathan E; Hoon Han, Seung; Hillgartner, Kaitlyn E; Davis, Chelsea S; Migler, Kalman B

2017-10-04

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 T ref = 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.

Extruded dry bean and other pulses

USDA-ARS?s Scientific Manuscript database

Extrusion is used commercially to produce high value breakfast and snack foods based on cereals such as wheat or corn. However, this processing method is not being commercially used for legume pulses seeds due to the perception that they do not expand well in extrusion. Extrusion cooking of pulses (...

Microstructure development and texture evolution of aluminum multi-port extrusion tube during the porthole die extrusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, X.H.

Aluminum multi-port extrusion tube is processed by the porthole die extrusion and the internal tube walls are welded through the solid state metallurgical bonding. In order to observe the development of grains and their orientations under severe plastic deformation and solid state welding, the extrusion butt together with the die is quenched immediately after extrusion to preserve the grain structure in the processing. The forming histories of selected material points are obtained by analyzing the optical microscopy graph. The evolution of the microstructure along the forming path is characterized by electro backscattered diffraction. It is found that geometrical dynamic recrystallizationmore » happens in the process. Grains are elongated, scattered at the transition zone and shear intensive zone, and then pinched off when they are pushed out from the die orifice. The shear-type orientations are predominant at the surface layer on the longitudinal section of the tube web and have penetrated into the intermediate layer. The rolling-type orientations are formed at the central layer. Texture gradient through the thickness of the tube web is observed. And cube orientated grains are found at the seam weld region. - Highlights: •Microstructure of extrusion butt is preserved after the micro scale porthole die extrusion. •Grain morphology history along forming path is investigated. •Texture evolutions on three material flows are present. •Texture gradient exists on the longitudinal section of the internal wall of profile. •Rolling-type and cube textures are found at the solid state welding region.« less

Obtaining ready-to-eat blue corn expanded snacks with anthocyanins using an extrusion process and response surface methodology.

PubMed

Escalante-Aburto, Anayansi; Ramírez-Wong, Benjamín; Torres-Chávez, Patricia Isabel; López-Cervantes, Jaime; Figueroa-Cárdenas, Juan de Dios; Barrón-Hoyos, Jesús Manuel; Morales-Rosas, Ignacio; Ponce-García, Néstor; Gutiérrez-Dorado, Roberto

2014-12-15

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).

Process Parameter Optimization of Extrusion-Based 3D Metal Printing Utilizing PW-LDPE-SA Binder System.

PubMed

Ren, Luquan; Zhou, Xueli; Song, Zhengyi; Zhao, Che; Liu, Qingping; Xue, Jingze; Li, Xiujuan

2017-03-16

Recently, with a broadening range of available materials and alteration of feeding processes, several extrusion-based 3D printing processes for metal materials have been developed. An emerging process is applicable for the fabrication of metal parts into electronics and composites. In this paper, some critical parameters of extrusion-based 3D printing processes were optimized by a series of experiments with a melting extrusion printer. The raw materials were copper powder and a thermoplastic organic binder system and the system included paraffin wax, low density polyethylene, and stearic acid (PW-LDPE-SA). The homogeneity and rheological behaviour of the raw materials, the strength of the green samples, and the hardness of the sintered samples were investigated. Moreover, the printing and sintering parameters were optimized with an orthogonal design method. The influence factors in regard to the ultimate tensile strength of the green samples can be described as follows: infill degree > raster angle > layer thickness. As for the sintering process, the major factor on hardness is sintering temperature, followed by holding time and heating rate. The highest hardness of the sintered samples was very close to the average hardness of commercially pure copper material. Generally, the extrusion-based printing process for producing metal materials is a promising strategy because it has some advantages over traditional approaches for cost, efficiency, and simplicity.

Process Parameter Optimization of Extrusion-Based 3D Metal Printing Utilizing PW–LDPE–SA Binder System

PubMed Central

Ren, Luquan; Zhou, Xueli; Song, Zhengyi; Zhao, Che; Liu, Qingping; Xue, Jingze; Li, Xiujuan

2017-01-01

Recently, with a broadening range of available materials and alteration of feeding processes, several extrusion-based 3D printing processes for metal materials have been developed. An emerging process is applicable for the fabrication of metal parts into electronics and composites. In this paper, some critical parameters of extrusion-based 3D printing processes were optimized by a series of experiments with a melting extrusion printer. The raw materials were copper powder and a thermoplastic organic binder system and the system included paraffin wax, low density polyethylene, and stearic acid (PW–LDPE–SA). The homogeneity and rheological behaviour of the raw materials, the strength of the green samples, and the hardness of the sintered samples were investigated. Moreover, the printing and sintering parameters were optimized with an orthogonal design method. The influence factors in regard to the ultimate tensile strength of the green samples can be described as follows: infill degree > raster angle > layer thickness. As for the sintering process, the major factor on hardness is sintering temperature, followed by holding time and heating rate. The highest hardness of the sintered samples was very close to the average hardness of commercially pure copper material. Generally, the extrusion-based printing process for producing metal materials is a promising strategy because it has some advantages over traditional approaches for cost, efficiency, and simplicity. PMID:28772665

A hybrid modeling system designed to support decision making in the optimization of extrusion of inhomogeneous materials

NASA Astrophysics Data System (ADS)

Kryuchkov, D. I.; Zalazinsky, A. G.

2017-12-01

Mathematical models and a hybrid modeling system are developed for the implementation of the experimental-calculation method for the engineering analysis and optimization of the plastic deformation of inhomogeneous materials with the purpose of improving metal-forming processes and machines. The created software solution integrates Abaqus/CAE, a subroutine for mathematical data processing, with the use of Python libraries and the knowledge base. Practical application of the software solution is exemplified by modeling the process of extrusion of a bimetallic billet. The results of the engineering analysis and optimization of the extrusion process are shown, the material damage being monitored.

Historical review of die drool phenomenon during plastics extrusion

NASA Astrophysics Data System (ADS)

Musil, Jan; Zatloukal, Martin

2013-04-01

Die drool phenomenon is defined as unwanted spontaneous accumulation of extruded polymer melt on open faces of extrusion die during extrusion process. Such accumulated material builds up on the die exit and frequently or continually sticks onto the extruded product and thus damages it. Since die drool appears, extrusion process must be shut down and die exit must be manually cleaned which is time and money consuming. Although die drool is complex phenomenon and its formation mechanism is not fully understood yet, variety of proposed explanations of its formation mechanism and also many ways to its elimination can be found in open literature. Our review presents in historical order breakthrough works in the field of die drool research, shows many ways to suppress it, introduces methods for its quantitative evaluation and composition analysis and summarizes theories of die drool formation mechanism which can be helpful for extrusion experts.

Processing of sintered alpha SiC

NASA Technical Reports Server (NTRS)

Storm, R. S.

1984-01-01

Processing methods of sintered alpha SiC for engine applications are developed in a cost effective manner, using a submicron sized powder blended with sintering aids (boron and carbon). The processes for forming a green powder compact, such as dry pressing, cold isostatic pressing and green machining, slip casting, aqueous extrusion, plastic extrusion, and injection molding, are described. Dry pressing is the simplest route to component fabrication, and is carried out at approximately 10,000 psi pressure, while in the cold isostatic method the pressure could go as high as 20,000 psi. Surfactants are added to control settling rates and casting characteristics in the slip casting. The aqueous extrusion process is accomplished by a hydraulic ram forcing the aqueous mixture through a die. The plastic forming processes of extrusion and injection molding offer the potential of greater diversity in shape capacity. The physical properties of sintered alpha SiC (hardness, Young's modulus, shear modulus, and thermal diffusivity) are extensively tested. Corrosion resistance test results of silicon carbide are included.

Phytochemical profiles and antioxidant activity of processed brown rice products.

PubMed

Gong, Er Sheng; Luo, Shunjing; Li, Tong; Liu, Chengmei; Zhang, Guowen; Chen, Jun; Zeng, Zicong; Liu, Rui Hai

2017-10-01

The phytochemical profiles and antioxidant activity of free, soluble-conjugated, and bound fractions of brown rice and its processed products (textured rice, cooked rice and rice noodle) were studied. Nineteen phenolic acids were identified. Trans-ferulic acid was the most abundant monomeric phenolic acid with trans-trans-8-O-4' diferulic acid being most abundant diferulic acid. Processing increased the content of free phenolic acids, but decreased the content of soluble-conjugated phenolic acids. The content of bound phenolic acids was increased by improved extrusion cooking technology and cooking, but not affected by rice noodle extrusion. The total phenolic contents and antioxidant activities of free and soluble-conjugated fractions were decreased after processing, whereas those of bound fraction were increased by improved extrusion cooking technology and cooking, but not affected by rice noodle extrusion. Results indicated that whole foods designed for reducing chronic disease risk need to consider the effects of processing on phytochemical profiles and antioxidant activity of whole grains. Copyright © 2017 Elsevier Ltd. All rights reserved.

The formation of giant clastic extrusions at the end of the Messinian Salinity Crisis

NASA Astrophysics Data System (ADS)

Kirkham, Christopher; Cartwright, Joe; Hermanrud, Christian; Jebsen, Christopher

2018-01-01

This paper documents the discovery of five multi-km scale lensoid bodies that directly overlie the upper surface of the thick (>1 km) Messinian Evaporite sequence. They were identified through the analysis of 3D seismic data from the western Nile Cone. The convergence of the upper and lower bounding reflections of these lensoid bodies, their external and internal reflection configuration, the positive 'depositional' relief at their upper surface, and the stratal relationship with underlying and overlying deposits supports the interpretation that these are giant clastic extrusions. The interpretations combined with the stratal position of these clastic extrusions demonstrate a prior unsuspected link between periods of major environment change and basin hydrodynamics on a plate scale. All five lensoid bodies were extruded onto a single, seismically resolvable marker horizon correlatable with the end of the Messinian Salinity Crisis (Horizon M). It is argued that the source of these clastic extrusions is pre-Messinian in origin, which implies massive sediment remobilisation at depth in the pre-evaporitic succession and intrusion through the thick evaporite layer. We propose that the scale and timing of this dramatic event was primed and triggered by near-lithostatic overpressure in the pre-evaporitic sediments generated through (1) their rapid burial and loading during the Messinian Salinity Crisis and (2) catastrophic re-flooding during its immediate aftermath. The largest of these clastic extrusions has a volume of over c. 116 km3, making it amongst the largest extruded sedimentary bodies described on Earth. The findings extend the understanding of the upper scale of other analogous clastic extrusions such as mud volcanoes and sediment-hosted hydrothermal systems. Following the 2006 eruption of the Lusi sediment-hosted hydrothermal system in Indonesia, an understanding of the upper scale limit of clastic extrusions has even greater societal relevance, in order to increase awareness of the risk posed by the potential size and longevity of future giant clastic extrusions.

Advanced applications of numerical modelling techniques for clay extruder design

NASA Astrophysics Data System (ADS)

Kandasamy, Saravanakumar

Ceramic materials play a vital role in our day to day life. Recent advances in research, manufacture and processing techniques and production methodologies have broadened the scope of ceramic products such as bricks, pipes and tiles, especially in the construction industry. These are mainly manufactured using an extrusion process in auger extruders. During their long history of application in the ceramic industry, most of the design developments of extruder systems have resulted from expensive laboratory-based experimental work and field-based trial and error runs. In spite of these design developments, the auger extruders continue to be energy intensive devices with high operating costs. Limited understanding of the physical process involved in the process and the cost and time requirements of lab-based experiments were found to be the major obstacles in the further development of auger extruders.An attempt has been made herein to use Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) based numerical modelling techniques to reduce the costs and time associated with research into design improvement by experimental trials. These two techniques, although used widely in other engineering applications, have rarely been applied for auger extruder development. This had been due to a number of reasons including technical limitations of CFD tools previously available. Modern CFD and FEA software packages have much enhanced capabilities and allow the modelling of the flow of complex fluids such as clay.This research work presents a methodology in using Herschel-Bulkley's fluid flow based CFD model to simulate and assess the flow of clay-water mixture through the extruder and the die of a vacuum de-airing type clay extrusion unit used in ceramic extrusion. The extruder design and the operating parameters were varied to study their influence on the power consumption and the extrusion pressure. The model results were then validated using results from experimental trials on a scaled extruder which seemed to be in reasonable agreement with the former. The modelling methodology was then extended to full-scale industrial extruders. The technical and commercialsuitability of using light weight materials to manufacture extruder components was also investigated. The stress and deformation induced on the components, due to extrusion pressure, was analysed using FEA and suitable alternative materials were identified. A cost comparison was then made for different extruder materials. The results show potential of significant technical and commercial benefits to the ceramic industry.

Physicochemical, functional, and nutritional characteristics of stabilized rice bran form tarom cultivar.

PubMed

Rafe, Ali; Sadeghian, Alireza; Hoseini-Yazdi, Seyedeh Zohreh

2017-05-01

Extrusion is a multistep thermal process which has been utilized in a wide spectrum of food preparations. The effect of extrusion processing on the physicochemical, nutritional, and functional properties of Tarom cultivar rice bran was studied. However, the color of rice bran was improved by extrusion processing, but the protein content was reduced in the stabilized rice bran, which can be related to the denaturation of protein. Extrusion had also a reduction significant effect on the phytic acid as well as vitamin E in rice bran. However, the content of niacin, riboflavin, pantothenic acid, and folic acid remained unchanged, but the dietary fiber was enhanced which has beneficial health effect on human consumption. In comparison with unstabilized rice bran, water holding capacity was enhanced, but the oil absorption capacity was reduced. Foaming capacity and foaming stability of extruded rice bran was more than that of untreated rice bran, although they were less than that of rice bran protein concentrate/isolate. In general, the extrusion process improves some functional and nutritional properties of rice bran which are valuable to industrial applications and have potential as ingredient in food to improve consumer health.

Thermal Inactivation of Feline Calicivirus in Pet Food Processing.

PubMed

Haines, J; Patel, M; Knight, A I; Corley, D; Gibson, G; Schaaf, J; Moulin, J; Zuber, S

2015-12-01

Extrusion is the most common manufacturing process used to produce heat-treated dry dog and cat food (pet food) for domestic use and international trade. Due to reoccurring outbreaks of notifiable terrestrial animal diseases and their impact on international trade, experiments were undertaken to demonstrate the effectiveness of heat-treated extruded pet food on virus inactivation. The impact of extrusion processing in a pet food matrix on virus inactivation has not been previously reported and very few inactivation studies have examined the thermal inactivation of viruses in complex food matrices. The feline calicivirus vaccine strain FCV F-9 was used as a surrogate model RNA virus pathogen. Small-scale heat inactivation experiments using animal-derived pet food raw materials showed that a > 4 log10 reduction (log10 R) in infectivity occurred at 70 °C prior to reaching the minimum extrusion manufacturing operating temperature of 100 °C. As anticipated, small-scale pressure studies at extrusion pressure (1.6 MPa) showed no apparent effect on FCV F-9 inactivation. Additionally, FCV F-9 was shown not to survive the acidic conditions used to produce pet food palatants of animal origin that are typically used as a coating after the extrusion process.

[Effect of extrusion on protein and starch bioavailability in corn and lima bean flour blends].

PubMed

Pérez-Navarrete, Cecilia; Betancur-Ancona, David; Casotto, Meris; Carmona, Andrés; Tovar, Juscelino

2007-09-01

Extrusion is used to produce crunchy expanded foods, such as snacks. The nutritional impact of this process has not been studied sufficiently. In this study, in vitro and in vivo protein and starch bioavailability was evaluated in both raw and extruded corn (Zea mays)(C) and lima bean (Phaseolus lunatus)(B) flour blends, prepared in 75C/25B and 50C/ 50B (p/p) proportions. These were processed with a Brabender extruder at 160 degrees C, 100 rpm and 15.5% moisture content. Proximate composition showed that in the extruded products protein and ash contents increased whereas the fat level decreased. In vitro protein digestibility was higher in the extrudates (82%) than in the raw flours (77%). Potentially available starch and resistant starch contents decreased with extrusion. The in vitro assays indicated that extrusion improved protein and starch availability in the studied blends. In vivo bioavailability was evaluated using the rice weevil (Sithophilus oryzae) as a biological model. The most descriptive biomarkers of the changes suggested by the in vivo tests were body protein content (increased by extrusion) and intestinal a-amylase activity (decreased by processing). Overall, results suggest that extrusion notably increases the nutritional quality of corn and lima bean flour blends.

The impact of extrusion on the nutritional composition, dietary fiber and in vitro digestibility of gluten-free snacks based on rice, pea and carob flour blends.

PubMed

Arribas, C; Cabellos, B; Sánchez, C; Cuadrado, C; Guillamón, E; Pedrosa, M M

2017-10-18

Consumers and the food industry are demanding healthier products. Expanded snacks with a high nutritional value were developed from different rice, pea and carob flour blends. The proximate composition, starch (total and resistant), amylose and amylopectin, dietary fiber (soluble and insoluble) contents, and the in vitro protein digestibility of different rice-legume formulations, were evaluated before and after the extrusion process. Compared with the corresponding non-extruded blends (control), the extrusion treatment did not change the total protein content, however, it reduced the soluble protein (61-86%), the fat (69-92%) and the resistant starch contents (100%). The total starch content of all studied blends increased (2-19%) after extrusion. The processing increased the in vitro protein digestibility, reaching values around 88-95% after extrusion. Total dietary fiber was reduced around 30%, and the insoluble fraction was affected to a larger extent than the soluble fraction by the extrusion process. Because of its balanced nutritional composition, high dietary fiber content, as well as low energy density, these novel gluten-free snack-like foods could be considered as functional foods and a healthier alternative to commercially available gluten-containing or gluten-free and low nutritional value snacks.

Effect of tube processing methods on the texture and grain boundary characteristics of 14YWT nanostructured ferritic alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aydogan, E.; Pal, S.; Anderoglu, O.

In this paper, texture and microstructure of tubes and plates fabricated from a nanostructured ferritic alloy (14YWT), produced either by spray forming followed by hydrostatic extrusion (Process I) or hot extrusion and cross-rolling a plate followed by hydrostatic tube extrusion (Process II) have been characterized in terms of their effects on texture and grain boundary character. Hydrostatic extrusion results in a combination of plane strain and shear deformations which generate low intensity α- and γ-fiber components of {001}<110> and {111}<110> together with a weak ζ-fiber component of {011}<211> and {011}<011>. In contrast, multi-step plane strain deformation by hot extrusion andmore » cross-rolling of the plate leads to a strong texture component of {001}<110> together with a weaker {111}<112> component. Although the total strains are similar, shear dominated deformation leads to much lower texture indexes compared to plane strain deformations. Further, the texture intensity decreases after hydrostatic extrusion of the alloy plate formed by plane strain deformation, due to a lower number of activated slip systems during shear dominated deformation. Finally and notably, hot extruded and cross-rolled plate subjected to plane strain deformation to ~50% engineering strain creates only a modest population of low angle grain boundaries, compared to the much larger population observed following the combination of plane strain and shear deformation of ~44% engineering strain resulting from subsequent hydrostatic extrusion.« less

Effect of tube processing methods on the texture and grain boundary characteristics of 14YWT nanostructured ferritic alloys

DOE PAGES

Aydogan, E.; Pal, S.; Anderoglu, O.; ...

2016-03-08

In this paper, texture and microstructure of tubes and plates fabricated from a nanostructured ferritic alloy (14YWT), produced either by spray forming followed by hydrostatic extrusion (Process I) or hot extrusion and cross-rolling a plate followed by hydrostatic tube extrusion (Process II) have been characterized in terms of their effects on texture and grain boundary character. Hydrostatic extrusion results in a combination of plane strain and shear deformations which generate low intensity α- and γ-fiber components of {001}<110> and {111}<110> together with a weak ζ-fiber component of {011}<211> and {011}<011>. In contrast, multi-step plane strain deformation by hot extrusion andmore » cross-rolling of the plate leads to a strong texture component of {001}<110> together with a weaker {111}<112> component. Although the total strains are similar, shear dominated deformation leads to much lower texture indexes compared to plane strain deformations. Further, the texture intensity decreases after hydrostatic extrusion of the alloy plate formed by plane strain deformation, due to a lower number of activated slip systems during shear dominated deformation. Finally and notably, hot extruded and cross-rolled plate subjected to plane strain deformation to ~50% engineering strain creates only a modest population of low angle grain boundaries, compared to the much larger population observed following the combination of plane strain and shear deformation of ~44% engineering strain resulting from subsequent hydrostatic extrusion.« less

Influence of processing conditions on apparent viscosity and system parameters during extrusion of distiller's dried grains-based snacks.

PubMed

Singha, Poonam; Muthukumarappan, Kasiviswanathan; Krishnan, Padmanaban

2018-01-01

A combination of different levels of distillers dried grains processed for food application (FDDG), garbanzo flour and corn grits were chosen as a source of high-protein and high-fiber extruded snacks. A four-factor central composite rotatable design was adopted to study the effect of FDDG level, moisture content of blends, extrusion temperature, and screw speed on the apparent viscosity, mass flow rate or MFR, torque, and specific mechanical energy or SME during the extrusion process. With increase in the extrusion temperature from 100 to 140°C, apparent viscosity, specific mechanical energy, and torque value decreased. Increase in FDDG level resulted in increase in apparent viscosity, SME and torque. FDDG had no significant effect (p > .5) on mass flow rate. SME also increased with increase in the screw speed which could be due to the higher shear rates at higher screw speeds. Screw speed and moisture content had significant negative effect ( p  <   .05) on the torque. The apparent viscosity of dough inside the extruder and the system parameters were affected by the processing conditions. This study will be useful for control of extrusion process of blends containing these ingredients for the development of high-protein high-fiber extruded snacks.

LINER FOR EXTRUSION BILLET CONTAINERS

DTIC Science & Technology

Rokide-process alumina and zirconia coatings and a Udimet 700 superalloy liner were evaluated by extrusion of 3 1/2-in. billets of Inconel 713C...One coating did with stand extrusion at 3450 F without apparent wear. The Udimet 700 liner did not show wear at 2000 F, but did react with the TZM

Optimized manufacture of nuclear fuel cladding tubes by FEA of hot extrusion and cold pilgering processes

NASA Astrophysics Data System (ADS)

Gaillac, Alexis; Ly, Céline

2018-05-01

Within the forming route of Zirconium alloy cladding tubes, hot extrusion is used to deform the forged billets into tube hollows, which are then cold rolled to produce the final tubes with the suitable properties for in-reactor use. The hot extrusion goals are to give the appropriate geometry for cold pilgering, without creating surface defects and microstructural heterogeneities which are detrimental for subsequent rolling. In order to ensure a good quality of the tube hollows, hot extrusion parameters have to be carefully chosen. For this purpose, finite element models are used in addition to experimental tests. These models can take into account the thermo-mechanical coupling conditions obtained in the tube and the tools during extrusion, and provide a good prediction of the extrusion load and the thermo-mechanical history of the extruded product. This last result can be used to calculate the fragmentation of the microstructure in the die and the meta-dynamic recrystallization after extrusion. To further optimize the manufacturing route, a numerical model of the cold pilgering process is also applied, taking into account the complex geometry of the tools and the pseudo-steady state rolling sequence of this incremental forming process. The strain and stress history of the tube during rolling can then be used to assess the damage risk thanks to the use of ductile damage models. Once validated vs. experimental data, both numerical models were used to optimize the manufacturing route and the quality of zirconium cladding tubes. This goal was achieved by selecting hot extrusion parameters giving better recrystallized microstructure that improves the subsequent formability. Cold pilgering parameters were also optimized in order to reduce the potential ductile damage in the cold rolled tubes.

Magnetic resonance imaging evidence of meniscal extrusion in medial meniscus posterior root tear.

PubMed

Choi, Chul-Jun; Choi, Yun-Jin; Lee, Jae-Jeong; Choi, Chong-Hyuk

2010-12-01

The purpose of this study was to evaluate the relation between meniscal extrusion on magnetic resonance imaging (MRI) and tearing of the posterior root of the medial meniscus, as well as to understand the relation between meniscal extrusion and chondral lesions. From January 2007 to December 2008, 387 consecutive cases of medial meniscal tears were treated arthroscopically. Of these cases, 248 (64.1%) with MRI were reviewed. Arthroscopic findings were reviewed for the type of tear and medial compartment cartilage lesion. Root tear was defined as a radial tear in the posterior horn of the medial meniscus near the tibial spine (i.e., within 5 mm of the root attachment). An MRI scan of the knee was used to evaluate the presence and extent of meniscal extrusion. Meniscal extrusion of 3 mm or greater was considered pathologic. Arthroscopic findings were compared with respect to the extent of meniscal extrusion. There were 98 male patients and 150 female patients. The mean age was 53.5 years (range, 15 to 81 years). The results showed 127 cases (51.2%) in which the medial meniscus had meniscal extrusion of 3 mm or greater. Posterior root tears were found in 66 (26.6%) of the 248 knees. The mean meniscal extrusion in patients with root tear was 3.8 ± 1.4 mm, whereas the mean extrusion of those who had no root tear was 2.7 ± 1.3 mm. We found an association between pathologic meniscal extrusion and root tear (P < .001). Meniscal extrusion showed a low positive predictive value (39%) and specificity (58%) with regard to the meniscal root tear. Meniscal extrusion was also significantly correlated with severity of chondral lesions (P < .001). Considerable extrusion (≥3 mm) can be associated with tearing of the medial meniscus root and chondral lesion of the medial femoral condyle. Level IV, therapeutic case series. Copyright © 2010 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Frictional conditions between alloy AA6060 aluminium and tool steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wideroee, Fredrik; Welo, Torgeir

The frictional conditions in the new process of screw extrusion of aluminium have been investigated. The contact behaviour between the aluminum alloy and the tool steel in the extruder is vital for understanding the extrusion process. Using a compressive-rotational method for frictional measurements the conditions for unlubricated sticking friction between aluminum alloy AA6060 and tool steel at different combinations of temperatures and pressures have been investigated. In this method the samples in the form of disks are put under hydrostatic pressure while simultaneously being rotated at one end. Pins made from contrast material have been inserted into the samples tomore » measure the deformation introduced. This approach along with 3D simulations form a method for determining the frictional conditions. The paper describes the test method and the results. It was found that the necessary pressure for sticking to occur between the aluminum AA6060 and the different parts of the extruder is heavily influenced by the temperature.« less

Production Process of Biocompatible Magnesium Alloy Tubes Using Extrusion and Dieless Drawing Processes

NASA Astrophysics Data System (ADS)

Kustra, Piotr; Milenin, Andrij; Płonka, Bartłomiej; Furushima, Tsuyoshi

2016-06-01

Development of technological production process of biocompatible magnesium tubes for medical applications is the subject of the present paper. The technology consists of two stages—extrusion and dieless drawing process, respectively. Mg alloys for medical applications such as MgCa0.8 are characterized by low technological plasticity during deformation that is why optimization of production parameters is necessary to obtain good quality product. Thus, authors developed yield stress and ductility model for the investigated Mg alloy and then used the numerical simulations to evaluate proper manufacturing conditions. Grid Extrusion3d software developed by authors was used to determine optimum process parameters for extrusion—billet temperature 400 °C and extrusion velocity 1 mm/s. Based on those parameters the tube with external diameter 5 mm without defects was manufactured. Then, commercial Abaqus software was used for modeling dieless drawing. It was shown that the reduction in the area of 60% can be realized for MgCa0.8 magnesium alloy. Tubes with the final diameter of 3 mm were selected as a case study, to present capabilities of proposed processes.

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

PubMed Central

Daurio, Dominick; Medina, Cesar; Saw, Robert; Nagapudi, Karthik; Alvarez-Núñez, Fernando

2011-01-01

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. PMID:24310598

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

NASA Astrophysics Data System (ADS)

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).

Examining the Effect of the Die Angle on Tool Load and Wear in the Extrusion Process

NASA Astrophysics Data System (ADS)

Nowotyńska, Irena; Kut, Stanisław

2014-04-01

The tool durability is a crucial factor in each manufacturing process, and this also includes the extrusion process. Striving to achieve the higher product quality should be accompanied by a long-term tool life and production cost reduction. This article presents the comparative research of load and wear of die at various angles of working cone during the concurrent extrusion. The numerical calculations of a tool load during the concurrent extrusion were performed using the MSC MARC software using the finite element method (FEM). Archard model was used to determine and compare die wear. This model was implemented in the software using the FEM. The examined tool deformations and stress distribution were determined based on the performed analyses. The die wear depth at various working cone angles was determined. Properly shaped die has an effect on the extruded material properties, but also controls loads, elastic deformation, and the tool life.

Processing Characteristics and Properties of the Cellular Products Made by Using Special Foaming Agents

NASA Astrophysics Data System (ADS)

Garbacz, Tomasz; Dulebova, Ludmila

2012-12-01

The paper describes the manufacturing process of extruded products by the cellular extrusion method, and presents specifications of the blowing agents used in the extrusion process as well as process conditions. The process of cellular extrusion of thermoplastic materials is aimed at obtaining cellular shapes and coats with reduced density, presenting no hollows on the surface of extruder product and displaying minimal contraction under concurrent maintenance of properties similar to properties of products extruded by means of the conventional method. In order to obtain cellular structure, the properties of extruded product are modified by applying suitable plastic or inserting auxiliary agents.

The 2006 lava dome eruption of Merapi Volcano (Indonesia): Detailed analysis using MODIS TIR

NASA Astrophysics Data System (ADS)

Carr, Brett B.; Clarke, Amanda B.; Vanderkluysen, Loÿc

2016-02-01

Merapi is one of Indonesia's most active and dangerous volcanoes. Prior to the 2010 VEI 4 eruption, activity at Merapi during the 20th century was characterized by the growth and collapse of a series of lava domes. Periods of very slow growth were punctuated by short episodes of increased eruption rates characterized by dome collapse-generated pyroclastic density currents (PDCs). An eruptive event of this type occurred in May-June, 2006. For effusive eruptions such as this, detailed extrusion rate records are important for understanding the processes driving the eruption and the hazards presented by the eruption. We use thermal infrared (TIR) images from the Moderate Resolution Imaging Spectrometer (MODIS) instrument on NASA's Aqua and Terra satellites to estimate extrusion rates at Merapi Volcano during the 2006 eruption using the method of Harris and Ripepe (2007). We compile a set of 75 nighttime MODIS images of the eruptive period to produce a detailed time series of thermal radiance and extrusion rate that reveal multiple phases of the 2006 eruption. These data closely correspond to the published ground-based observational record and improve observation density and detail during the eruption sequence. Furthermore, additional analysis of radiance values for thermal anomalies in Band 21 (λ = 3.959 μm) of MODIS images results in a new framework for detecting different styles of activity. We successfully discriminate among slow dome growth, rapid dome growth, and PDC-producing dome collapse. We also demonstrate a positive correlation between PDC frequency and extrusion rate, and provide evidence that extrusion rate can increase in response to external events such as dome collapses or tectonic earthquakes. This study represents a new method of documenting volcanic activity that can be applied to other similar volcanic systems.

Optimization of drug loading to improve physical stability of paclitaxel-loaded long-circulating liposomes.

PubMed

Kannan, Vinayagam; Balabathula, Pavan; Divi, Murali K; Thoma, Laura A; Wood, George C

2015-01-01

The effect of formulation and process parameters on drug loading and physical stability of paclitaxel-loaded long-circulating liposomes was evaluated. The liposomes were prepared by hydration-extrusion method. The formulation parameters such as total lipid content, cholesterol content, saturated-unsaturated lipid ratio, drug-lipid ratio and process parameters such as extrusion pressure and number of extrusion cycles were studied and their impact on drug loading and physical stability was evaluated. A proportionate increase in drug loading was observed with increase in the total phospholipid content. Cholesterol content and saturated lipid content in the bilayer showed a negative influence on drug loading. The short-term stability evaluation of liposomes prepared with different drug-lipid ratios demonstrated that 1:60 as the optimum drug-lipid ratio to achieve a loading of 1-1.3 mg/mL without the risk of physical instability. The vesicle size decreased with an increase in the extrusion pressure and number of extrusion cycles, but no significant trends were observed for drug loading with changes in process pressure or number of cycles. The optimization of formulation and process parameters led to a physically stable formulation of paclitaxel-loaded long-circulating liposomes that maintain size, charge and integrity during storage.

Effects of extrusion temperature and dwell time on aflatoxin levels in cottonseed.

PubMed

Buser, Michael D; Abbas, Hamed K

2002-04-24

Cottonseed is an economical source of protein and is commonly used in balancing livestock rations; however, its use is typically limited by protein, fat, gossypol, and aflatoxin contents. Whole cottonseed was extruded to determine if the temperature and dwell time (multiple stages of processing) associated with the process affected aflatoxin levels. The extrusion temperature study showed that aflatoxin levels were reduced by an additional 33% when the cottonseed was extruded at 160 degrees C as compared to 104 degrees C. Furthermore, the multiple-pass extrusion study indicated that aflatoxin levels were reduced by an additional 55% when the cottonseed was extruded four times as compared to one time. To estimate the aflatoxin reductions due to extrusion temperature and dwell time, the least mean fits obtained for the individual studies were combined. Total estimated reductions of 55% (three stages of processing at 104 degrees C), 50% (two stages of processing at 132 degrees C), and 47% (one stage of processing at 160 degrees C) were obtained from the combined equations. If the extreme conditions (four stages of processing at 160 degrees C) of the evaluation studies are applied to the combined temperature and processing equation, the resulting aflatoxin reduction would be 76%.

Carotenoid Stability during Dry Milling, Storage, and Extrusion Processing of Biofortified Maize Genotypes.

PubMed

Ortiz, Darwin; Ponrajan, Amudhan; Bonnet, Juan Pablo; Rocheford, Torbert; Ferruzzi, Mario G

2018-05-09

Translation of the breeding efforts designed to biofortify maize ( Z. mays) genotypes with higher levels of provitamin A carotenoid (pVAC) content for sub-Saharan Africa is dependent in part on the stability of carotenoids during postharvest through industrial and in-home food processing operations. The purpose of this study was to simulate production of commercial milled products by determining the impact of dry milling and extrusion processing on carotenoid stability in three higher pVAC maize genotypes (C17xDE3, Orange ISO, Hi27xCML328). Pericarp and germ removal of biofortified maize kernels resulted in ∼10% loss of total carotenoids. Separating out the maize flour fraction (<212 μm) resulted in an additional ∼15% loss of total carotenoids. Carotenoid degradation was similar across milled maize fractions. Dry-milled products of Orange ISO and Hi27xCML328 genotypes showed ∼28% pVAC loss after 90-days storage. Genotype C17xDE3, with highest levels of all- trans-β-carotene, showed a 68% pVAC loss after 90-day storage. Extrusion processing conditions were optimal at 35% extrusion moisture, producing fully cooked instant maize flours with high pVAC retention (70-93%). These results support the notion that postharvest losses in maize milled fractions may be dependent, in part, on genotype and that extrusion processing may provide an option for preserving biofortified maize products.

Novel fiber-rich lentil flours as snack-type functional foods: an extrusion cooking effect on bioactive compounds.

PubMed

Morales, P; Berrios, J De J; Varela, A; Burbano, C; Cuadrado, C; Muzquiz, M; Pedrosa, M M

2015-09-01

Novel snack-type functional foods based on extruded lentil flours could convey the related health benefit of their bioactive compounds, provide a gluten-free alternative to consumers, and potentially increase the consumption of pulses. Extrusion treatment promoted an increase in galactopinitol, ciceritol, raffinose, stachyose and total α-galactoside content, in most lentil flours. As α-galactosides may act as prebiotics, they could convey beneficial effects to human and monogastric animals. Conversely, extrusion significantly (p < 0.05) reduced the inositol hexaphosphate content to less phosphorylated phytates (inositol pentaphosphate and inositol tetraphosphate), which provide health effects. The gluten-free formulation (control formulation #3) presented the highest significant (p < 0.05) drop in the inositol hexaphosphate of 14.7-fold decrease, but had a large increase in inositol pentaphosphate, due to extrusion processing. These two results are desirable in the finished product. Extrusion also caused a significant (p < 0.05) reduction in the trypsin content and completely inactivated lectin, in all processed samples.

Research on Extrusion of Rubber Composites Reinforced by Short Fibers Orientation Based on FEA

NASA Astrophysics Data System (ADS)

Zhang, Dewei; Wang, Chuansheng; Shen, Bo; Li, Shaoming; Bian, Huiguang

2018-06-01

In recent years, rubber composites reinforced by short fibers has been researched deeply, because of its good performances such as higher wear resistance, higher cut resistance and so on. Some research results indicated that if short fibers get orientation in rubber composites, the performances of rubber products could be promoted greatly. But how to make short fibers get orientation in rubber matrix during extrusion is still a real problem. And there are many parameters affect the short fibers orientation. So, in this paper, the effects of die structure including expansion-die and dam-expansion-die on extrusion flow field of short fiber and rubber composite material during extrusion process has been researched by Polyflow. And the FEA results about the pressure field, velocity field and the velocity vector of the rubber composites flow field indicate that, comparing with expansion-die and the dam-expansion-die, the latter one is better for the extrusion process of rubber composites and making short fibers get radial orientation in rubber matrix.

Effect of Microstructure on the Mechanical Properties of Extruded Magnesium and a Magnesium Alloy

NASA Astrophysics Data System (ADS)

McGhee, Paul

The main objective of this research was to investigate the relationship between the fatigue behavior and crystallographic texture evolution of magnesium (Mg) alloys with a range of microalloying element content processed under various extrusion conditions. Several Mg alloys were processed under a range of extrusion temperatures, extrusion ratios, and alloying content and tested under monotonic and cyclic fatigue loading conditions: fully-reversed condition tested at strain amplitudes of 0.15% - 1.00% in strain-control mode. After fatigue testing, Mg microstructural analysis was performed using SEM, TEM, optical microscopy, and X-ray diffraction techniques. Microstructural observations revealed significant grain refinement through a combination of zirconium (Zr) addition and hot-extrusion, producing fine equiaxed grain structure with grain sizes ranging between 1-5 microm. Texture analysis and partial compression testing results showed that the initial texture of the extruded alloy gradually evolved upon compressive loading along the c-axes inducing extension twinning creating a strong basal texture along the extrusion direction. Full tensile and compression testing at room temperature showed that the combination of hot extrusion and Zr addition can further refine the grains of the Mg alloys microstructure and enhance the texture while simultaneously enhancing the mechanical properties.

Metal flow and temperature in direct extrusion of large-size aluminum billets

NASA Astrophysics Data System (ADS)

Valberg, Henry; Costa, André L. M.

2018-05-01

FEM-analysis is used to study thermo-mechanical conditions in aluminum rod extrusion for billets with large size corresponding to that used in industrial production. In the analysis, focus is on how the metal flow and the temperature conditions in the extrusion material is affected by the extrusion velocity in terms of the ram speed used in the extrusion process. In the study, metal flow is characterized by the deformations in extrusion subjected to a perfect grid pattern, consisting of orthogonal crossing lines, added into the longitudinal mid-plane of the initial billet. The analysis shows that metal flow in extrusion conducted at a low ram speed of 1 mms-1, is predicted significantly different from that at a high speed of 5 mms-1, or above. As regards the thermal conditions in the extrusion material, they are also predicted significantly different, at the low and the high ram speed level. A likely explanation why metal flow is different at low and high ram speeds may be that flow is altered because of the concurrent change in the temperature field within the billet.

Microstructure and properties of ultrafine grain nickel 200 after hydrostatic extrusion processes

NASA Astrophysics Data System (ADS)

Sitek, R.; Krajewski, C.; Kamiński, J.; Spychalski, M.; Garbacz, H.; Pachla, W.; Kurzydłowski, K. J.

2012-09-01

This paper presents the results of the studies of the structure and properties of ultrafine grained nickel 200 obtained by hydrostatic extrusion processes. Microstructure was characterized by means of optical microscopy and electron transmission microscopy. Corrosion resistance was studied by impedance and potentiodynamic methods using an AutoLab PGSTAT 100 potentiostat in 0.1 M Na2SO4 solution and in acidified (by addition of H2SO4) 0.1 M NaCl solution at pH = 4.2 at room temperature. Microhardness tests were also performed. The results showed that hydrostatic extrusion produces a heterogeneous, ultrafine-grained microstructure in nickel 200. The corrosive resistance tests showed that the grain refinement by hydrostatic extrusion is accompanied by a decreased corrosive resistance of nickel 200.

Studies on Microstructure and Thermoelectric Properties of p-Type Bi-Sb-Te Based Alloys by Gas Atomization and Hot Extrusion Processes

NASA Astrophysics Data System (ADS)

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.

Improved corn protein (zein) extrusion processing

USDA-ARS?s Scientific Manuscript database

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...

Extruder scale-up assessment in the process of extrusion-spheronization: comparison of radial and axial systems by a design of experiments approach.

PubMed

Désiré, Amélie; Paillard, Bruno; Bougaret, Joël; Baron, Michel; Couarraze, Guy

2013-02-01

Scaling-up the extrusion-spheronization process involves the separate scale-up of each of the five process steps: dry mixing, granulation, extrusion, spheronization, and drying. The aim of the study was to compare two screw extrusion systems regarding their suitability for scaling-up. Two drug substances of high- and low-solubility in water were retained at different concentrations as formulation variables. Different spheronization times were tested. The productivity of the process was followed up using the extrusion rate and yield. Pellets were characterized by their size and shape, and by their structural and mechanical properties. A response surface design of experiments was built to evaluate the influence of the different variables and their interactions on each response, and to select the type of extrusion which provides the best results in terms of product quality, the one which shows less influence on the product after scale-up ("scalability") and when the formula used changes ("robustness"), and the one which allows the possibility to adjust pellet properties with spheronization variables ("flexibility"). Axial system showed the best characteristics in terms of product quality at lab and industrial scales, the best robustness at industrial scale, and the best scalability, by comparison with radial system. Axial system thus appeared as the easiest scaled-up system. Compared to lab scale, the conclusions observed at industrial scale were the same in terms of product quality, but different for robustness and flexibility, which confirmed the importance to test the systems at industrial scale before acquiring the equipment.

Pulp extrusion at ultra-high consistencies : selection of water soluble polymers for process optimization

Treesearch

C. Tim Scott

2002-01-01

Pulp extrusion at ultra-high consistencies (20% to 40% solids) is a new process developed at USDA Forest Service, Forest Products Laboratory (FPL) to convert recovered papers, wastepaper, and papermill residuals into solid sheets or profiles for compression molding. This process requires adding a water-soluble polymer (WSP) to alter the rheological properties of the...

Analysis and modeling of hot extrusion die for its service life enhancement

NASA Astrophysics Data System (ADS)

Akhtar, Syed Sohail

Aluminum extrusion finds extensive application in the construction, automobile and aerospace industries. High pressures, elevated temperatures, complex and intricate section geometries lead to repeated mechanical and thermal stresses in the die and affiliated tooling. Product rework and rejects can be traced back to various defects spread over the die life cycle: die design, die manufacture and heat treatment, process parameters, inprocess die maintenance/correction and, billet type and quality. Therefore, improved and efficient service life of die and related tooling used in the extrusion press is one the most important factors in maximizing productivity and minimizing cost for ensuring the economical efficiency of an aluminum extrusion plant. How often a die has to be scrapped and replaced with a new one directly contributes to the commercial viability of producing a certain profile. The focus of the current work is on three distinct yet inter-related studies pertaining to the improvement of aluminum extrusion die. Study-A (Die Failure Analysis) is an investigation of various modes and critical failure types based on industrial data (Chapter-2 ), examination of failed dies and finite element simulation for identification of critical process parameters and design features in die fatigue-life (Chapter-3). In Study-B (Die Surface Hardening Treatment), two-stage controlled gas nitriding process for H13 steel is evaluated, both experimentally and numerically, in terms of nitrided case morphology and properties (Chapter-4) followed by experimental and numerical investigation of the effects of repeated nitriding (Chapter-5), pre-nitriding surface preparation (Chapter-6) and die profile geometry (Chapter-7) on nitriding performance in regard to die service life. In Study-C (Effect of Billet Quality on Die Life), the effect of billet quality and related influencing extrusion parameters on the die service life is investigated based on industrial data and some regression-based die life models are proposed (Chapter-8 ). This is followed by a detailed microstructural investigation of different billet samples and finite element analysis of extrusion process to observe the influence of smelter (primary) and recycled (secondary) billets on the useful life of extrusion die (Chapter-9).

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

PubMed

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-ranging pharmaceutical products.

Development of a simulation tool to analyze the orientation of LCPs during extrusion process

NASA Astrophysics Data System (ADS)

Ahmadzadegan, Arash

In this thesis, different aspects of the rheology and directionality of the liquid crystalline polymers (LCPs) are investigated. The rheology of LCPs are modeled with different rheological models in different die geometries. The final goal in modeling the rheology and directionality of LCPs is to have a better understanding of their rheology during extrusion processing methods inside extrusion dies and eventually produce more isotropic films of LCPs. An attempt to design a die geometry that produces more isotropic films was made and it was shown that it is possible to use the inertia of the polymer to generate a more isotropic velocity profile at the lip of the die. This isotropic velocity profile can lead to alignment of directors along the streamlines and produce an isotropic film of LCP. It is shown that the rheological properties of the LCP should be altered to have a very low viscosity for this type of die to work. To be able to investigate the effect of processing on directionality of LCPs, it is essential to develop a method to simulate the directionality based on processing conditions. As a result, a user defined function (UDF) code was added to ANSYSRTM ~FLUENTRTM~ to simulate the directionality of LCPs. The rheology of the LCP is modeled using power-law fluid model and the consistency index (K) and power-law index (n) were estimated based on the experimental measurements done with capillary rheometry. Three main phenomena that affect the directionality namely effects of Franks elastic energy, the effect of shear and the effect of movement of crystals with the bulk of polymer are investigated. The results of this simulation are close to physical phenomena seen in real LCPs. To quantify the directionality of the LCPs, the order parameter of the domain were calculated and compared for different flow and fluid conditions. All polymers including LCPs are viscoelastic fluids in molten state. To understand the rheology of LCPs, a die-swell experiment was carried out using LCP material and Polypropylene (PP). For this experiment a capillary die with two different land-lengths was designed and built. The die-swell of the materials were measured optically according to ISO standards and the dependence of the die swell for materials on rheological properties is investigated. To simulate the viscoelasticity of LCPs numerically, ANSYSRTM ~POLYFLOWRTM~ was used. ANSYSRTM ~POLYFLOWRTM~ has several viscoelastic models and is designed to simulate extrusion processes. The geometry of the capillary die designed for the experiments was modeled in ANSYSRTM ~POLYFLOWRTM~ and the results were compared with the experimental results obtained for LCP and PP. It is shown that the morphology of the polymer should be considered into account to have a correct simulation of die swell.

Codeformation processing of mechanically-dissimilar metal/intermetallic composites

NASA Astrophysics Data System (ADS)

Marte, Judson Sloan

A systematic and scientific approach has been applied to the study of codeformation processing. A series of composites having mechanically-dissimilar phases were developed in which the high temperature flow behavior of the reinforcement material could be varied independent of the matrix. This was accomplished through the use of a series of intermetallic matrix composites (IMCs) as discontinuous reinforcements in an otherwise conventional metal matrix composite. The IMCs are produced using an in-situ reaction synthesis technique, called the XD(TM) process. The temperature of the exothermic synthesis reaction, called the adiabatic temperature, has been calculated and shown to increase with increasing volume percentage of TiB2 reinforcement. Further, this temperature has been shown to effect the size and spacing of the TiB2, microstructural features which are often used in discontinuous composite strength models. Study of the high temperature flow behavior of the components of the metal/IMC composite is critical to the development of an understanding of codeformation. A series of compression tests performed at 1000° to 1200°C and strain-rates of 10-3 and 10-4 sec-1. Peak flow stresses were used to evaluate the influence of material properties and process conditions. These data were incorporated into phenomenologically-based constitutive equations that have been used to predict the flow behavior. It has been determined that plastic deformation of the IMCs occurs readily, and is largely TiB2 independent, at temperatures approaching the melting point of the intermetallic matrices. Ti-6Al-4V/IMC powder blends were extruded at high temperatures to achieve commensurately deformed microstructures. The results of codeformation processing were analyzed in terms of the plastic strain of the IMC particulates. IMC particle deformation was shown to increase with increasing IMC particle size, volume percentage of IMC, extrusion temperature, homologous temperature, extrusion strain-rate, and decreasing TiB2 reinforcement within the IMCs. A series of finite element models were developed to simulate codeformation processing via the extrusion of a discontinuously-reinforced composite. The results were evaluated through comparison between average equivalent strain in matrix and reinforcement elements. These results show that codeformation should increase with increasing volume percentage of IMC, homologous temperature, volume percentage of IMC, and decreasing IMC particle size. With the exception of the particle size, these results correlate to those of the experimental extrusion analysis.

Preparation and investigation of novel gastro-floating tablets with 3D extrusion-based printing.

PubMed

Li, Qijun; Guan, Xiaoying; Cui, Mengsuo; Zhu, Zhihong; Chen, Kai; Wen, Haoyang; Jia, Danyang; Hou, Jian; Xu, Wenting; Yang, Xinggang; Pan, Weisan

2018-01-15

Three dimensional (3D) extrusion-based printing is a paste-based rapid prototyping process, which is capable of building complex 3D structures. The aim of this study was to explore the feasibility of 3D extrusion-based printing as a pharmaceutical manufacture technique for the fabrication of gastro-floating tablets. Novel low-density lattice internal structure gastro-floating tablets of dipyridamole were developed to prolong the gastric residence time in order to improve drug release rate and consequently, improve bioavailability and therapeutic efficacy. Excipients commonly employed in the pharmaceutical study could be efficiently applied in the room temperature 3D extrusion-based printing process. The tablets were designed with three kinds of infill percentage and prepared by hydroxypropyl methylcellulose (HPMC K4M) and hydroxypropyl methylcellulose (HPMC E15) as hydrophilic matrices and microcrystalline cellulose (MCC PH101) as extrusion molding agent. In vitro evaluation of the 3D printed gastro-floating tablets was performed by determining mechanical properties, content uniformity, and weight variation. Furthermore, re-floating ability, floating duration time, and drug release behavior were also evaluated. Dissolution profiles revealed the relationship between infill percentage and drug release behavior. The results of this study revealed the potential of 3D extrusion-based printing to fabricate gastro-floating tablets with more than 8h floating process with traditional pharmaceutical excipients and lattice internal structure design. Copyright © 2017. Published by Elsevier B.V.

Solid state recycling of aluminium alloys via a porthole die hot extrusion process: Scaling up to production

NASA Astrophysics Data System (ADS)

Paraskevas, Dimos; Kellens, Karel; Deng, Yelin; Dewulf, Wim; Kampen, Carlos; Duflou, Joost R.

2017-10-01

Whereas industrial symbiosis has led to increased energy and resource efficiency in process industries, this concept has not yet been applied in discrete product manufacturing. Metal scrap is first conventionally recycled, for which substantial energy and resource efficiency losses have been reported. Recent research has however proven the feasibility of `meltless' recycling of light metal scrap, yielding a first glimpse of potential industrial symbiosis. Various solid state recycling techniques (such as recycling via hot extrusion or Spark Plasma Sintering) have been proposed for scrap consolidation directly into bulk products or semis by physical disruption and dispersion of the oxide surface film by imposing significant plastic and shear strain. Solid State Recycling (SSR) methods can omit substantial material losses as they bypass the metallurgical recycling step. In this context the case of direct production of bulk aluminium profiles via hot extrusion at industrial scale is demonstrated within this paper. The extrusion tests were performed directly into the production line, highlighting the scaling up potentials and the industrial relevance of this research. A significant amount of machining chips were collected, chemically cleaned and cold compacted into chip based billets with ˜80% relative density. Afterwards the scrap consolidation was achieved by imposing significant plastic and shear deformation into the material during hot extrusion through a modified 2-porthole extrusion die-set. The production process sequence along with microstructural investigations and mechanical properties comparison of the cast based profile used as reference versus the chip based profile are presented.

The effect of moisture content on physicochemical properties of extruded waxy and non-waxy rice flour.

PubMed

Jongsutjarittam, Ornpicha; Charoenrein, Sanguansri

2014-12-19

The properties of waxy rice flour (WRF) and non-waxy rice flour (RF) were modified using an extrusion process with different feeding material moisture contents. WRF was more affected by the thermomechanical stress from extrusion; consequently, it had a lower glass transition temperature but higher water solubility index (WSI) indicating higher molecular degradation than extruded RF. The lower moisture content of the feeding flour caused more severe flour damage (coarser surface of the extruded flour) and lowered relative crystallinity compared to higher moisture content processing. Moreover, low moisture content processing led to complete gelatinization, whereas, partial gelatinization occurred in the higher moisture content extrusion. Consequently, the extruded flours had a lower peak viscosity and gelatinization enthalpy but a higher water absorption index and WSI than native flour. In conclusion, the rice flour type and the moisture content of the extrusion feeding flour affected the physicochemical properties of the extruded flour. Copyright © 2014 Elsevier Ltd. All rights reserved.

Optimization of extrusion conditions for the production of instant grain amaranth-based porridge flour.

PubMed

Akande, Olamide A; Nakimbugwe, Dorothy; Mukisa, Ivan M

2017-11-01

Malnutrition is one of the foremost causes of death among children below 5 years in developing countries. Development of nutrient-dense food formulations using locally available crops has been proposed as a means to combat this menace. This study optimized the extrusion process for the production of a nutritious amaranth-based porridge flour. Least cost formulations containing grain amaranth, groundnut, iron-rich beans, pumpkin, orange-fleshed sweet potato, carrot, and maize were developed and evaluated by a sensory panel ( n  = 30) for acceptability using the 9-point hedonic scale. Extrusion process of the most acceptable porridge flour was optimized by response surface methodology (RSM). Barrel temperature (130-170°C) and feed moisture content (14%-20%) were the independent variables which significantly ( p  < .05) affected in vitro protein digestibility, vitamin A retention, total polyphenol, phytic content, and iron and zinc extractabilities. Optimization of the extrusion process improved the nutritional quality of the instant flour.

Effect of Mg content on the thermal stability and mechanical behaviour of PLLA/Mg composites processed by hot extrusion.

PubMed

Cifuentes, S C; Lieblich, M; López, F A; Benavente, R; González-Carrasco, J L

2017-03-01

In the field of bioabsorbable composites for biomedical applications, extrusion has been employed as a method to prepare homogeneous blends of polymeric matrices with bioactive ceramic fillers. In this work, the suitability of processing poly-l-lactic acid/Magnesium (PLLA/Mg) composites by hot extrusion has been assessed by a systematic characterization of PLLA/Mg composites containing different amounts of Mg particles up to 7wt%. The results show that extrusion causes a reduction of almost 20% in the viscosity average molecular weight of PLLA, which further decreases with increasing Mg content. Extrusion gave always rise to a homogeneous distribution of Mg particles within the PLLA matrix. This composite processing was not compromised by the degradation of the polymeric matrix because the processing temperature was always below the onset degradation temperature. In the processing conditions employed in the present work, degradation of the composite slightly increases as more Mg is added up to 5wt%, but is very high at 7wt%. This was also evident from the mechanical behaviour, so that Mg particles improved the stiffness and compression strength of neat PLLA until 5wt% of Mg content, which dropped drastically when the material had 7wt% of Mg. The filler strengthening factor decreases with the increment in Mg content. In order to obtain an optimised contribution of Mg particles, a balance between thermal degradation and mechanical resistance of PLLA must be achieved. Copyright © 2016 Elsevier B.V. All rights reserved.

Tailoring properties of commercially pure titanium by gradation extrusion

NASA Astrophysics Data System (ADS)

Bergmann, Markus; Rautenstrauch, Anja; Selbmann, René; de Oliveira, Raoni Barreto; Coelho, Rodrigo Santiago; Landgrebe, Dirk

2016-10-01

Commercially pure titanium (CP Ti) is of great importance in medical applications due to its attractive properties, such as high biocompatibility, excellent corrosion resistance and relatively low density and suitable stiffness. Compared to the commonly used Ti-6Al-4V alloy, its lower strength has to be increased. The most attractive approach is to subject CP Ti to severe plastic deformation (SPD) processes such as Equal Channel Angular Pressing (ECAP). The resulting decreased grain size in CP Ti yields a significant increase in hardness and strength. Common SPD-processes typically provide a uniform modification of the material. Their material efficiency and productivity are critical and limiting factors. A new approach is to tailor the material properties by using Gradation Extrusion, which produces a distinct gradient in microstructure and strength. The forming process combines a regular impact extrusion process and severe plastic deformation in the lateral area of the material. This efficient process can be integrated easily into forming process chains, for instance for dental implants. This paper presents the forming process and the applied die geometry. The results of numerical simulations are used to illustrate the potential of the process to modify and strengthen the titanium material. Experiments show that the material is successfully processed by gradation extrusion. By characterizing the hardness and its distribution within the formed parts the effects of the process are investigated.

Shear zone formation within the billet and metal flow through the die orifice in unlubricated axisymmetric forward and backward extrusion

NASA Astrophysics Data System (ADS)

Valberg, Henry; Costa, Andrè L. M.

2017-10-01

Metal flow inside the billet is known to be completely different in forward (FWE) and backward (BWE) Al-extrusion. A practical implication of this is that contamination near to the surface of the extrusion billet, or on the peripheral surface skin, tends to flow out of the die more readily in BWE than in FWE. It is therefore common in BWE to use a scalping operation on the billet to remove eventual sub-surface contamination that may be present. This additional working operation may be required in order to avoid surface quality problems on BWE profiles. In spite of the importance of metal flow in metals extrusion, there are still lack of knowledge about the topic. With recent progress in FEM-analysis for modelling deformation processing, however, it is now possible to perform accurate studies on metal flow phenomena by simulation on the computer. In our study, we are using the 3D FEM-program DEFORM® to model axisymmetric FWE and BWE in case of non-lubricated extrusion through a flat-faced die. Our primary focus is to consider the difference in appearance of shear zones present inside the extrusion billet for the two processes, including metal flow in the die mouth.

Meltlets(®) of soy isoflavones: process optimization and the effect of extrusion spheronization process parameters on antioxidant activity.

PubMed

Deshmukh, Ketkee; Amin, Purnima

2013-07-01

In the current research work an attempt was made to develop "Melt in mouth pellets" (Meltlets(®)) containing 40% herbal extract of soy isoflavones that served to provide antioxidants activity in menopausal women. The process of extrusion-spheronization was optimized for extruder speed, extruder screen size, spheronization speed, and time. While doing so the herbal extract incorporated in the pellet matrix was subjected to various processing conditions such as the effect of the presence of other excipients, mixing or kneading to prepare wet mass, heat generated during the process of extrusion, spheronization, and drying. Thus, the work further investigates the effect of these processing parameters on the antioxidant activity of the soy isoflavone herbal extract incorporated in the formula. Thereby, the antioxidant activity of the soya bean herbal extract, Meltlets(®) and of the placebo pellets was evaluated using DPPH free radical scavenging assay and total reduction capacity.

Parametric optimisation of heat treated recycling aluminium (AA6061) by response surface methodology

NASA Astrophysics Data System (ADS)

Ahmad, A.; Lajis, M. A.; Yusuf, N. K.; Shamsudin, S.; Zhong, Z. W.

2017-09-01

Alternating typical primary aluminium production with recycling route should benefit various parties, including the environment since the need of high cost and massive energy consumption will be ruled out. At present, hot extrusion is preferred as the effective solid-state recycling process compared to the typical method of melting the swarf at high temperature. However, the ideal properties of extruded product can only be achieved through a controlled process used to alter the microstructure to impart properties which benefit the working life of a component, which also known as heat treatment process. To that extent, this work ought to investigate the effect of extrusion temperature and ageing time on the hardness of the recycled aluminium chips. By employing Analysis of Variance (ANOVA) for full factorial design with centre point, a total of 11 runs were carried out randomly. Three dissimilar extrusion temperatures were used to obtain gear-shape billet. Extruded billets were cut and ground before entering the treatment phase at three different ageing times. Ageing time was found as the influential factor to affect the material hardness, rather than the extrusion temperature. Sufficient ageing time allows the impurity atoms to interfere the dislocation phenomena and yield great hardness. Yet, the extrusion temperatures still act to assist the bonding activities via interparticle diffusion transport matter.

Tribological investigations of the applicability of surface functionalization for dry extrusion processes

NASA Astrophysics Data System (ADS)

Teller, Marco; Prünte, Stephan; Ross, Ingo; Temmler, André; Schneider, Jochen M.; Hirt, Gerhard

2017-10-01

Cold extrusion processes are characterized by large relative contact stresses combined with a severe surface enlargement of the workpiece. Under these process conditions a high risk for galling of workpiece material to the tool steel occurs especially in processing of aluminum and aluminum alloys. In order to reduce adhesive wear lubricants for separation of workpiece and tool surfaces are used. As a consequence additional process steps (e.g. preparation and cleaning of workpieces) are necessary. Thus, the realization of a dry forming process is aspired from an environmental and economic perspective. In this paper a surface functionalization with self-assembled-monolayers (SAM) of the tool steels AISI D2 (DIN 1.2379) and AISI H11 (DIN 1.2343) is evaluated by a process-oriented tribological test. The tribological experiment is able to resemble and scale the process conditions of cold extrusion related to relative contact stress and surface enlargement for the forming of pure aluminum (Al99.5). The effect of reduced relative contact stress, surface enlargement and relative velocity on adhesive wear and tool lifetime is evaluated. Similar process conditions are achievable by different die designs with decreased extrusion ratios and adjusted die angles. The effect of surface functionalization critically depends on the substrate material. The different microstructure and the resulting differences in surface chemistry of the two tested tool steels appear to affect the performance of the tool surface functionalization with SAM.

Modelling highly deformable metal extrusion using SPH

NASA Astrophysics Data System (ADS)

Prakash, Mahesh; Cleary, Paul W.

2015-05-01

Computational modelling is often used to reduce trial extrusions through accurate defect prediction. Traditionally, metal extrusion is modelled using mesh based finite element methods. However, large plastic deformations can lead to heavy re-meshing and numerical diffusion. Here we use the mesh-less smoothed particle hydrodynamics method since it allows simulation of large deformations without re-meshing and the tracking of history dependent properties such as plastic strain making it suitable for defect prediction. The variation in plastic strain and deformation for aluminium alloy in a cylindrical 3D geometry with extrusion ratio and die angle is evaluated. The extrusion process is found to have three distinct phases consisting of an initial sharp rise in extrusion force, a steady phase requiring constant force and terminating in a sharp decline in force as metal is completely extruded. Deformation and plastic strain increased significantly with extrusion ratio but only moderately with die angle. Extrusion force increased by 150 % as the extrusion ratio increased from 2:1 to 4:1 but had only a marginal change with die angle. A low strain zone in the centre of the extruded product was found to be a function of extrusion ratio but was persistent and did not vary with die angle. Simulation of a complex 3D building industry component showed large variations in plastic strain along the length of the product at two scales. These were due to change in metal behaviour as extrusion progressed from phase 1 to phase 2. A stagnation zone at the back of the die was predicted that could lead to the "funnel" or "pipe" defect.

Numerical Simulations of As-Extruded Mg Matrix Composites Interpenetrated by Metal Reinforcement

NASA Astrophysics Data System (ADS)

Y Wang, H.; Wang, S. R.; Yang, X. F.; Li, P.

2017-12-01

The interpenetrating magnesium composites reinforced by three-dimensional braided stainless steel wire reinforcement were fabricated and investigated. The extrusion processes of the composites in different conditions were carried out and simulated by finite element method using the DEFORM-3D software. The results show that the matrix and reinforcement of the composites form a good interfacial bonding and the grains were refined by extrusion and the influence of reinforcement, which are in accordance with the enhanced strength and degraded plasticity. The combined quality between the matrix and reinforcement can be strengthened in extrusion chamber where occurred large strain and suffered intense stress, and the effective stress of the material increases continuously with the increase in extrusion ratio and the decrease in extrusion speed until it reaches a stable value.

Development of an Ointment Formulation Using Hot-Melt Extrusion Technology.

PubMed

Bhagurkar, Ajinkya M; Angamuthu, Muralikrishnan; Patil, Hemlata; Tiwari, Roshan V; Maurya, Abhijeet; Hashemnejad, Seyed Meysam; Kundu, Santanu; Murthy, S Narasimha; Repka, Michael A

2016-02-01

Ointments are generally prepared either by fusion or by levigation methods. The current study proposes the use of hot-melt extrusion (HME) processing for the preparation of a polyethylene glycol base ointment. Lidocaine was used as a model drug. A modified screw design was used in this process, and parameters such as feeding rate, barrel temperature, and screw speed were optimized to obtain a uniform product. The product characteristics were compared with an ointment of similar composition prepared by conventional fusion method. The rheological properties, drug release profile, and texture characteristics of the hot-melt extruded product were similar to the conventionally prepared product. This study demonstrates a novel application of the hot-melt extrusion process in the manufacturing of topical semi-solids.

Low-Flammability PTFE for High-Oxygen Environments

NASA Technical Reports Server (NTRS)

Walle, E.; Fallon, B.; Sheppard, A.

1986-01-01

Modified forming process removes volatile combustible materials. Flammability of cable-wrapping tape reduced by altering tape-manufacturing process. In new manufacturing process, tape formed by proprietary process of screw extrusion, followed by washing in solvent and drying. Tape then wrapped as before. Spectrogram taken after extrusion, washing, and drying shows lower hydrocarbon content. PTFE formed by new process suited to oxygen-rich environments. Safe in liquid oxygen of Space Shuttle tank and in medical uses; thin-wall shrinkable tubing in hospital test equipment, surgical instruments, and implants.

Development of expanded extrusion food products for an Advanced Life Support system.

PubMed

Zasypkin, D V; Lee, T C

1999-01-01

Extrusion processing was proposed to provide texture and to expand the variety of cereal food products in an isolated Advanced Life Support (ALS) system. Rice, wheat, and soy are the baseline crops selected for growing during long-term manned space missions. A Brabender single-screw laboratory extruder (model 2003, L/D 20:1), equipped with round nozzles of various lengths, was used as a prototype of a small-size extruder. Several concepts were tested to extend the variety and improve the quality of the products, to decrease environmental loads, and to promote processing stability. These concepts include: the blending of wheat and soybean flour, the extrusion of a coarser rice flour, separation of wheat bran, and optimization of the extruder nozzle design. An optimal nozzle length has been established for the extrusion of rice flour. Bran separating was necessary to improve the quality of wheat extrudates.

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

PubMed

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.

Industrial Technology Modernization Program. Project 44. Modernize Facility Equipment and Processes. Volume 1. Revision 2. Phase 2

DTIC Science & Technology

1988-05-01

OF EXTRUSION HLSGFLN XRSO ICO-F XTUINPPER PATE CUT-OFF EXTRUSION I I 7 TUMBLE S TUMBLE HEAT &SORT TML I IEC SPANK & PIERCE P A SPANK & PIERCEI IF...implementation, the Walnut Cell will utilize 50% of the "As-Is" floor space. 106 -EGREflSEII HSL 59 i.CUT OFF EXTRUSION 2. SPANK & PIERCE I 3.DEGREASE 4...FEMALE MALE CUT-OFF EXTRUSION I HOUSNG HOUNG I SPANK & PIERCE SPANK & PIERCE I CLEAN I DEG SE I I DEGREASEI I C P P E R PL A TE I HEAT TREAT I HEAT

Analog Modeling of the Interplay between Subduction and Lateral Extrusion in the European Alps

NASA Astrophysics Data System (ADS)

van Gelder, I. E.; Willingshofer, E.; Sokoutis, D.

2014-12-01

In the European Alps lateral extrusion is traditionally viewed as a lithospheric scale process that is related to northward indentation of a weak orogenic wedge (the eastern Alps) by a rigid indenter in upper plate position (the Adriatic plate). Critical for the efficiency of the extrusion process is the presence of a 'free boundary' at high angle to the indentation direction. The 'free boundary' in the eastern Alps is the result of the eastward extending Pannonian realm synchronous to indentation. However, indentation has become debatable as recent high-resolution tomography suggests that the Adriatic mantle lithosphere subducted under the extruding Alps. These findings raise first order questions related to: (a) the partitioning of deformation between lateral extrusion of the upper plate and coeval subduction of Adria, (b) the rheology of the lower and upper plates, and (c) the rheology of the plate contact controlling the amount of extrusion on the upper plate vs. accretion on the lower plate.In this analog modeling study, we couple for the first time lateral extrusion tectonics to subduction of the lower plate; thus, extrusion taking place in the upper plate. Within the lithospheric scale models, the lithospheres of the two plates are weakly coupled along an inclined boundary and have contrasting mantle lithosphere strength (stronger in the subducting plate). The interplay of extrusion vs subduction is inferred by varying the mechanical boundary conditions, e.g. the degree of resistance at the 'unconstrained' margin, the strength contrast between the upper and the lower plates and the width of the indented region.The experimental results emphasize that extrusion in the eastern Alps is compatible with coeval subduction of the Adriatic plate. The first experimental series suggests that the following mechanical conditions play a key role in the interplay between extrusion and subduction: (a) the extruding plate is weaker than the subducting plate, (b) the plate contact is weak in order to trigger the subduction of the lower plate, and (c) the eastern boundary is weak and thus allows for accommodating the extruding upper plate.

Hydrostatic Microextrusion of Steel and Copper

NASA Astrophysics Data System (ADS)

Berti, Guido; Monti, Manuel; D'Angelo, Luciano

2011-05-01

The paper presents an experimental investigation based on hydrostatic micro extrusion of billets in low carbon steel and commercially pure copper, and the relevant results. The starting billets have a diameter of 0.3 mm and are 5 mm long; a high pressure generator consisting of a manually operated piston screw pump is used to pressurize the fluid up to 4200 bar, the screw pump is connected through a 3-way distribution block to the extrusion die and to a strain gauge high pressure sensor. The sensor has a full scale of 5000 bar and the extrusion pressure is acquired at a sampling rate of 2 kHz by means of an acquisition program written in the LabVIEW environment. Tests have been conducted at room temperature and a lubricant for wire drawing (Chemetall Gardolube DO 338) acts both as the pressurizing fluid and lubricant too. In addition, billets were graphite coated. Different fluid pressures and process durations have been adopted, resulting in different extrusion lengths. The required extrusion pressure is much higher than in non-micro forming operations (this effect is more evident for steel). On the cross section of the extruded parts, hardness and grain size distribution have been measured, the former through Vickers micro hardness (10 g load) tests. In the case of the extrusion of copper, the material behaves as in microdrawing process. In the case of the extrusion of steel, the hardness increases from the core to the surface as in the drawing process, but with lower values. The analysis evidenced the presence of the external layer, but its thickness is about 1/3 of the external layer in the drawn wire and the grains appear smaller than in the layer of the drawn wire. The extruding force required along the extruding direction is higher (22-24 N) than the drawing force along the same direction (12 N): being the material, the reduction ratio, the die sliding length the same in both cases, the higher extrusion force should be caused by a higher tangential friction force and/or a higher redundant work of deformation and/or a different material behaviour. Which is the real mechanism is not clear at present, but surface layer grains in extrusion are more deformed than in wire drawing. For this reason the deformation inhomogeneity increases in extrusion and the material under the highly deformed surface layer should be subjected to lower strains, strain hardening and finally resulting in lower hardness.

Hydrostatic Microextrusion of Steel and Copper

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berti, Guido; Monti, Manuel; D'Angelo, Luciano

2011-05-04

The paper presents an experimental investigation based on hydrostatic micro extrusion of billets in low carbon steel and commercially pure copper, and the relevant results. The starting billets have a diameter of 0.3 mm and are 5 mm long; a high pressure generator consisting of a manually operated piston screw pump is used to pressurize the fluid up to 4200 bar, the screw pump is connected through a 3-way distribution block to the extrusion die and to a strain gauge high pressure sensor. The sensor has a full scale of 5000 bar and the extrusion pressure is acquired at amore » sampling rate of 2 kHz by means of an acquisition program written in the LabVIEW environment. Tests have been conducted at room temperature and a lubricant for wire drawing (Chemetall Gardolube DO 338) acts both as the pressurizing fluid and lubricant too. In addition, billets were graphite coated. Different fluid pressures and process durations have been adopted, resulting in different extrusion lengths. The required extrusion pressure is much higher than in non-micro forming operations (this effect is more evident for steel). On the cross section of the extruded parts, hardness and grain size distribution have been measured, the former through Vickers micro hardness (10 g load) tests. In the case of the extrusion of copper, the material behaves as in microdrawing process. In the case of the extrusion of steel, the hardness increases from the core to the surface as in the drawing process, but with lower values. The analysis evidenced the presence of the external layer, but its thickness is about 1/3 of the external layer in the drawn wire and the grains appear smaller than in the layer of the drawn wire. The extruding force required along the extruding direction is higher (22-24 N) than the drawing force along the same direction (12 N): being the material, the reduction ratio, the die sliding length the same in both cases, the higher extrusion force should be caused by a higher tangential friction force and/or a higher redundant work of deformation and/or a different material behaviour. Which is the real mechanism is not clear at present, but surface layer grains in extrusion are more deformed than in wire drawing. For this reason the deformation inhomogeneity increases in extrusion and the material under the highly deformed surface layer should be subjected to lower strains, strain hardening and finally resulting in lower hardness.« less

Antioxidant activity and polyphenolic compound stability of lentil-orange peel powder blend in an extrusion process.

PubMed

Rathod, Rahul P; Annapure, Uday S

2017-03-01

Lentil contains substantial amount of protein, carbohydrate, fibre and other nutrients and orange peels powder rich in carbohydrate and fiber content The present study was aimed to investigate the effects of extrusion processing parameter on the level of total phenolic content (TPC), total flavonoid content (TFC), total tannin content and antioxidant activity of lentil-orange peel powder blend, also to investigate the possibility of blend as a candidate for production of protein rich extruded product by using response surface methodology. It was observed that, the physicochemical properties and sensory characteristics of lentil-orange peel based extrudate were highly dependent on process variables. The blend of lentil and orange peel powder has a huge potential for extrusion to produce ready-to-eat extruded with good acceptance. The overall best quality product was optimized and obtained at 16% moisture, 150 °C die temperature and 200 rpm screw speed. Extrusion process increased nutritional value of extruded product with TPC and TFC of 70.4 and 67.62% respectively and antioxidant activity of 60.6%. It showed higher stability at 150 °C with intermediate feed moisture content and despite the use of high temperatures in the extrusion-cooking is possible to minimize the loss of bioactive compounds to achieve products. Thus, results indicated that blend of lentil and orange peel may be used as raw material for the production of extruded snacks with great nutritional value.

Impacts of Scarification and Degermination on the Expansion Characteristics of Select Quinoa Varieties during Extrusion Processing.

PubMed

Aluwi, Nicole A; Gu, Bon-Jae; Dhumal, Gaurav S; Medina-Meza, Ilce G; Murphy, Kevin M; Ganjyal, Girish M

2016-12-01

Extrusion of 2 quinoa varieties, Cherry Vanilla and Black (scarified and unscarified) and a mixed quinoa variety, Bolivian Royal (scarified and degermed) were studied for their extrusion characteristics. A corotating twin-screw extruder with a 3 mm round die was used. Feed moisture contents of 15%, 20%, and 25% (wet basis) were studied. The extruder barrel temperature was kept constant at 140 °C and screw speeds were varied from 100, 150, and 200 revolutions per minutes. Process responses (specific mechanical energy, back pressure, and torque) and product responses (expansion ratio, unit density, and water absorption index/water solubility index) were evaluated. The degermed Bolivian Royal showed the highest expansion in comparison to all other varieties, attributed to its significantly low levels of fat, fiber, and protein. The scarified Cherry Vanilla resulted in the lowest expansion ratio. This was attributed to the increase in the protein content from the removal of the outer layer. The results indicate that all the varieties performed differently in the extrusion process due to their modification processes as well as the individual variety characteristics. © 2016 Institute of Food Technologists®.

Conditioning of material properties by micro rotary swaging

NASA Astrophysics Data System (ADS)

Ishkina, Svetlana; Schenck, Christian; Kuhfuss, Bernd

2018-05-01

Cold forming initiates a change of the material properties like flow stress and hardness. Due to work hardening and the accompanied loss of formability some intermediate heat treatment may become necessary in multi-stage forming processes. One possibility to avoid this heat treatment is to adjust the forming characteristics in terms of flow stress and formability by rotary swaging. This process is particularly suitable not only for producing of the target geometry but also for modifying of the material properties during the process and thus, rotary swaging can prepare the parts for further forming, such as extrusion. In this contribution, the process chain "rotary swaging - extrusion" for austenite stainless steel AISI304 was investigated. The forming characteristics of the semi-finished products for the extrusion were influenced by the previous swaging process. The conditioning by changing of the microstructure, the work hardening and the geometry of the processed wires was achieved by the process design. For this purpose, the geometry of the swaging dies, the feeding velocity as well as the process kinematics (eccentric swaging) and a stroke following angle Δɸ were varied. In particular, the novel geometry of the swaging dies with extraordinary sloped faces generated a non-symmetric material flow with severe shear deformation and thus an extreme change of the microstructure. The required forming force of the following extrusion process reflected the range of achievable conditioning. The micro rotary swaging process positively improved the formability of AISI304 by work softening.

Development of Rolling Schedules for Equal Channel Angular Extrusion (ECAE)-Processed AZ31 Magnesium Alloy

DTIC Science & Technology

2016-04-01

Processed AZ31 Magnesium Alloy Sheet by Laszlo J Kecskes, Vincent H Hammond, Michael Eichhorst, Norman Herzig, and Lothar Meyer...Angular Extrusion (ECAE)–Processed AZ31 Magnesium Alloy Sheet by Laszlo J Kecskes and Vincent H Hammond Weapons and Materials Research...successfully reduced into 1.5-mm-thick sheets . Two sets of plates, each with a different texture type, were evaluated. Microscopic examination of

Bioactive compounds and antioxidant capacity of extruded snack-type products developed from novel formulations of lentil and nutritional yeast flours.

PubMed

Ciudad-Mulero, María; Barros, Lillian; Fernandes, Ângela; Berrios, José De J; Cámara, Montaña; Morales, Patricia; Fernández-Ruiz, Virginia; Ferreira, Isabel C F R

2018-02-21

Pulses are well known to be gluten-free functional foods that provide a rich source of nutritional and healthy compounds with antioxidant-promoting activity. In the present study, the bioactive compounds, dietary fibre, arabinoxylans, individual phenolic compounds and tocopherols, were evaluated in different lentil flours (raw and extruded at 140 and 160 °C) formulated with nutritional yeasts, along with the changes induced by the extrusion process. The total dietary fibre and arabinoxylan content significantly (p < 0.05) increased after the extrusion process while a significant decrease of all tocopherol isoforms was also observed. Catechin, caffeic, kaempferol and quercetin derivatives were identified in the raw and extruded lentil flours. The decreases of total phenolic and individual phenolic compounds were directly related to the extrusion temperature; total phenolics and catechin hexoside exhibited a larger decrease in the lentil flours formulated with higher content of nutritional yeast (12 and 16%). The antioxidant activity results, determined using different assays, reflected the important effect of extrusion processing and food ingredients.

Physico-chemical properties and extrusion behaviour of selected common bean varieties.

PubMed

Natabirwa, Hedwig; Muyonga, John H; Nakimbugwe, Dorothy; Lungaho, Mercy

2018-03-01

Extrusion processing offers the possibility of processing common beans industrially into highly nutritious and functional products. However, there is limited information on properties of extrudates from different bean varieties and their association with raw material characteristics and extrusion conditions. In this study, physico-chemical properties of raw and extruded Bishaz, K131, NABE19, Roba1 and RWR2245 common beans were determined. The relationships between bean characteristics and extrusion conditions on the extrudate properties were analysed. Extrudate physico-chemical and pasting properties varied significantly (P < 0.05) among bean varieties. Expansion ratio and water solubility decreased, while bulk density, water absorption, peak and breakdown viscosities increased as feed moisture increased. Protein exhibited significant positive correlation (P < 0.05) with water solubility index, and negative correlations (P < 0.05) with water absorption, bulk density and pasting viscosities. Iron and dietary fibre showed positive correlation while total ash exhibited negative correlation with peak viscosity, final viscosity and setback. Similar trends were observed in principal component analysis. Extrudate physico-chemical properties were found to be associated with beans protein, starch, iron, zinc and fibre contents. Therefore, bean chemical composition may serve as an indicator for beans extrusion behaviour and could be useful in selection of beans for extrusion. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Characterization of agar/soy protein biocomposite films: Effect of agar on the extruded pellets and compression moulded films.

PubMed

Garrido, T; Etxabide, A; Guerrero, P; de la Caba, K

2016-10-20

Agar/soy protein biocomposite films were successfully processed by extrusion and compression moulding, obtaining transparent and homogeneous films. The conformational changes occurred during the extrusion process and the effect of agar on the final properties were analyzed. As shown by differential scanning calorimetry (DSC) and specific mechanical energy (SME) values, during the extrusion process protein denatured and unfolded protein chains could interact with agar. These interactions were analyzed by Fourier transform infrared spectroscopy (FTIR) and the secondary structure was determined from the amide I band. Those interactions were supported by the decrease of film solubility. Furthermore, the good compatibility between agar and soy protein was confirmed by the images from scanning electron microscopy (SEM). Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of parameters controlling the extrusion step in fused filament fabrication (FFF) process applied to polymers using numerical simulation

NASA Astrophysics Data System (ADS)

Shahriar, Bakrani Balani; Arthur, Cantarel; France, Chabert; Valérie, Nassiet

2018-05-01

Extrusion is one of the oldest manufacturing processes; it is widely used for manufacturing finished and semi-finished products. Moreover, extrusion is also the main process in additive manufacturing technologies such as Fused Filament Fabrication (FFF). In FFF process, the parts are manufactured layer by layer using thermoplastic material. The latter in form of filament, is melted in the liquefier and then it is extruded and deposited on the previous layer. The mechanical properties of the printed parts rely on the coalescence of each extrudate with another one. The coalescence phenomenon is driven by the flow properties of the melted polymer when it comes out the nozzle just before the deposition step. This study aims to master the quality of the printed parts by controlling the effect of the parameters of the extruder on the flow properties in the FFF process. In the current study, numerical simulation of the polymer coming out of the extruder was carried out using Computational Fluid Dynamics (CFD) and two phase flow (TPF) simulation Level Set (LS) method by 2D axisymmetric module of COMSOL Multiphysics software. In order to pair the heat transfer with the flow simulation, an advection-diffusion equation was used. Advection-diffusion equation was implemented as a Partial Differential Equation (PDE) in the software. In order to define the variation of viscosity of the polymer with temperature, the rheological behaviors of two thermoplastics were measured by extensional rheometer and using a parallel-plate configuration of an oscillatory rheometer. The results highlight the influence of the environment temperature and the cooling rate on the temperature and viscosity of the extrudate exiting from the nozzle. Moreover, the temperature and its corresponding viscosity at different times have been determined using numerical simulation. At highest shear rates, the extrudate undergoes deformation from typical cylindrical shape. These results are required to predict the coalescence of filaments, a step towards understanding the mechanical properties of the printed parts.

Effect of extrusion process on the functional properties of high amylose corn starch edible films and its application in mango (Mangifera indica L.) cv. Tommy Atkins.

PubMed

Calderón-Castro, Abraham; Vega-García, Misael Odín; de Jesús Zazueta-Morales, José; Fitch-Vargas, Perla Rosa; Carrillo-López, Armando; Gutiérrez-Dorado, Roberto; Limón-Valenzuela, Víctor; Aguilar-Palazuelos, Ernesto

2018-03-01

Starch is an attractive raw material as ingredient for edible film manufacture because of its low cost, abundant availability, renewability, and biodegradability. Nevertheless, starch based films exhibit several disadvantages such as brittleness and poor mechanical and barrier properties, which restrict its application for food packaging. The use of the extrusion technology as a pretreatment of the casting technique to change the starch structure in order to obtain edible films, may constitute an alternative to generate coatings with good functional properties and maintain longer the postharvest quality and shelf life of fruits. For this reason, the objective of this study was to optimize the conditions of an extrusion process to obtain a formulation of modified starch to elaborate edible films with good functional properties using the casting technique and assess the effect during the storage when applied on a model fruit. The best conditions of the extrusion process and concentration of plasticizers were obtained using response surface methodology. From optimization study, it was found that appropriate conditions to obtain starch edible films with the best mechanical and barrier properties were an extrusion temperature of 100 °C and a screw speed of 120 rpm, while the glycerol content was 16.73%. Also, once applied in fruit, the loss of quality attributes was diminished.

'The effect of inulin addition on structural and textural properties of extruded products under several extrusion conditions': The effect of inulin addition on structural and textural properties of rice flour extrudates.

PubMed

Tsokolar-Tsikopoulos, Konstantinos C; Katsavou, Ioanna D; Krokida, Magdalini K

2015-10-01

The growing consumer demand for healthy snacks has turned the interest of industry and research in the development of new ready-to-eat products, enriched with dietary fibers. Inulin is a soluble fiber with a neutral taste that promotes the good function of the intestine. Rice flour extrudates were produced under various extrusion temperatures, screw speeds, feed moisture concentrations and inulin replacement levels. The objective of this study was to investigate the effect of the material characteristics and the extrusion conditions on the structural and textural properties of the extrudates. Simple mathematical models were used for properties correlation with process conditions and through regression analysis it was revealed that there is a significant effect of extrusion temperature, screw speed, feed moisture content and inulin concentration on the final properties. Both density and maximum stress increased when moisture content and inulin concentration increased, while they decreased when extrusion temperature and screw speed increased. These results were also strengthened by scanning electron microscopy. The highest expansion ratio was presented when decreasing all process conditions apart from screw speed.

Extrusion and rheology of fine particulate ceramic pastes

NASA Astrophysics Data System (ADS)

Mazzeo, Fred Anthony

A rheological study was conducted on an extruded blend of two alumina powders, Alcoa A-3500-SG and Reynolds ERC. These extruded blends were mixed in four compositions, varying in distribution modulus. This work focuses on the interaction of the composition components, mainly particle size distribution and amount of water at a constant binder amount. The rheological parameters of extruded pastes, Sigma, Tau, alpha and beta, were determined by using capillary rheometry modeling by the methodology set forth by Benbow and Bridgwater. This methodology makes use of capillary rheometer to determine extrusion parameters, which describe the flow behavior of a paste. The parameter values are indirectly determined by extrapolating high shear rate information obtained by the extrusion process. A goal of this research was to determine fundamental rheological properties directly from fundamental rheological equations of state. This was accomplished by assessing the material properties by using a dynamic stress rheometer. The rheological parameters used in this study to characterize the paste are elastic modulus, viscosity, tan delta, and relaxation time. This technique approaches a step closer in understanding the microstructural influence on flow behavior of a paste. This method directly determines rheological properties by using linear viscoelastic theory, giving a quantitative analysis of material properties. A strong correlation between the elastic modulus and sigma, and viscosity and alpha is shown to exist, indicating a relationship between these two techniques. Predictive process control methodology, based on particle packing modeling, quantitatively determined structural parameters useful in evaluating a composition. The determined parameters are: distribution modulus, interparticle separation distance, porosity, and particle crowding index, which are important to understand the extrudates packed state. A connection between the physical structure of the extrudate and its rheological behavior, can lead to a better understanding of what conditions and parameters are necessary to characterize the extrusion process. This study shows how particle packing and particle size influences the rheological behavior of the paste. Results showed that an optimally packed system was found to occur at a distribution modulus of 0.51. This system was determined both experimentally and quantitatively to exhibit the lowest porosity at any water content. The 0.51 system required a lower amount of water to extrude and the parameters of both rheological techniques agreed well, in which all parameters are influenced by the packing state of the paste, and a consistent trend was generally found. The capillary rheometry results can be explained by the strong interaction of particles that occurs at high shear rates. The dynamic stress rheometer results can be explained by the particle packing characteristics, interparticle separation distance and particle-crowding index, and the capillary forces between particles. The excess amount of liquid that is present in the structure decreases the role of the capillary attraction between particles and an increase in the particle size role on the rheological behavior of the pastes occurs.

The development of a stable, coated pellet formulation of a water-sensitive drug, a case study: development of a stable core formulation.

PubMed

Fitzpatrick, Shaun; Taylor, Scott; Booth, Steven W; Newton, Michael J

2006-01-01

A development program has been carried out to provide a stable extrusion/spheronisation pellet formulation for a highly water-soluble drug, sitagliptin, which undergoes a change in physical form on processing and is subject to hydrolytic decomposition. A conventional extrusion/spheronization formulation resulted in significant degradation of the drug. The inclusion of glyceryl monostearate into the formulation was found to reduce the water levels required to such a level that there was no significant degradation of the drug during processing to form pellets. The use of a ram extruder to screen formulations with small quantities minimizes the need for the drug in the formulation-screening process, and the results from this method of extrusion were found to be translatable to the use of a screen extruder, which allowed scale-up of the process.

Illustration of cross flow of polystyrene melts through a coathanger die

NASA Astrophysics Data System (ADS)

Schöppner, V.; Henke, B.

2015-05-01

To design an optimal coathanger die with a uniform flow rate distribution and low pressure drop, it is essential to understand the flow conditions in the die. This is important because the quality of the product is influenced by the flow velocity and the flow rate distribution. In extrusion dies, cross flows also occur in addition to the main flow, which flow perpendicular to the main flow. This results in pressure gradients in the extrusion direction, which have an influence on flow distribution and pressure drop in the die. In recent decades, quantitative representation and analysis of physical flow processes have made considerable progress in predicting the weather, developing drive technologies and designing aircraft using simulation methods and lab trials. Using the flow-line method, the flow is analyzed in flat film extrusion dies with a rectangular cross-section, in particular cross flows. The simplest method to visualize the flow is based on the measurement of obstacle orientation in the flow field by adding individual particles. A near-surface flow field can be visualized by using wool or textile yarns. By sticking thin, frayed at the ends of strands of wool surface that is to be examined cross flows, near-wall profiles of the flow and vortex and separation regions can be visualized. A further possibility is to add glass fibers and analyze the fiber orientation by microscopy and x-ray analysis. In this paper the influence of process parameters (e.g. melt temperatures and throughput) on cross flow and fiber orientation is described.

Evaluation of selected properties of gluten-free instant gruels processed under various extrusion-cook- ing conditions.

PubMed

Kręcisz, Magdalena; Wójtowicz, Agnieszka

2017-01-01

For consumers suffering with gluten intolerance, the only way to manage the condition is to avoid foods which are high in gluten. Instant gruels, processed from gluten-free corn and rice by extrusion cooking, could be used as a ready meal both for children and for adults on a gluten-free diet. The aim of the study was to evaluate the effects of various processing conditions on selected characteristics of corn-rice instant gruels. Corn-rice mixtures (75:25 and 50:50) were processed at 12, 14, 16 and 18% of initial moisture content, using an extruder with screw speeds of 80, 100 and 120 rpm. Bulk density, water absorption and solubility, gel formation, color and sensory characteristics were assessed, under various pro- cessing conditions and with various corn:rice ratios. The composition of the raw materials, initial moisture content and screw speed applied during processing affected the characteristics of the corn-rice extruded instant gruels. Increasing the amount of rice in the recipe from 25 to 50% resulted in decreased bulk density, water solubility, volumetric gel formation ability and b* value. Increasing the initial moisture content increased the bulk density, L*, a* and b* intensity, and gel formation index values of extrudates made with a 75:25 corn-rice recipe. Increased rpm increased extrudate solubility and water absorption, if the initial moisture content was higher than 14%. The highest scores for overall acceptability were found for milk suspensions of 75:25 and 50:50 corn-rice instant gruels processed at 12 and 14% of initial moisture content, at 120 rpm. Corn-rice instant gruels can be successfully produced by extrusion-cooking. Variable param- eters, like the initial moisture content of raw materials or screw speed during processing significantly affected the properties of the products. An understanding of the effects of processing conditions on some qualities of extruded instant gruels allows more desirable products to be created. Moreover, the various components can be used for extruded products for consumers on gluten-free diets. Functional additives incorporated in the recipe to improve the nutritional value of the extrudates, which will be investigated in our upcoming research.

Power Factor Study Reduces Energy Costs at Aluminum Extrusion Plant (Alcoa North American Extrusions)

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2001-08-01

This case study is the latest in a series on industrial firms who are implementing energy efficient technologies and system improvements into their manufacturing processes. The case studies document the activities, savings, and lessons learned on these projects.

Structure and mechanical characterization of Mg-Nd-Zn alloys prepared by different processes

NASA Astrophysics Data System (ADS)

Dvorský, D.; Kubásek, J.; Vojtěch, D.; Voňavková, I.; Veselý, M.; Čavojský, M.

2017-02-01

Magnesium alloys containing about 3 wt. % of Nd and 0.5 wt. % of Zn are considered as promising materials for application in transport and medical industry. Properly treated materials can reach ultimate tensile strength (UTS) higher than 300 MPa. Also the corrosion resistance of these alloys is superior to many other magnesium-based materials. Present work is focused on the preparation of Mg-3Nd-0.5Zn magnesium alloy by classical casting and subsequent thermal treatment. As-cast material was extruded at 400 °C, with extrusion ratio equal to 16 and velocity of 0.2 mm/s. The effect of thermal treatment and also strong plastic deformation during extrusion on final structure conditions and mechanical properties is specified. Present results confirm significant improvement of tensile yield strength (TYS) and UTS after extrusion process as a consequence of fine-grained structure combined with precipitation strengthening. Beside, texture strengthening in the direction parallel to the extrusion has been observed too.

Turbidimetric method for the determination of particle sizes in polypropylene/clay-composites during extrusion.

PubMed

Becker, Wolfgang; Guschin, Viktor; Mikonsaari, Irma; Teipel, Ulrich; Kölle, Sabine; Weiss, Patrick

2017-01-01

Nanocomposites with polypropylene as matrix material and nanoclay as filler were produced in a double twin screw extruder. The extrusion was monitored with a spectrometer in the visible and near-infrared spectral region with a diode array spectrometer. Two probes were installed at the end at the extruder die and the transmission spectra were measured during the extrusion. After measuring the transmission spectra and converting into turbidity units, the particle distribution density was calculated via numerical linear equation system. The distribution density function shows either a bimodal or mono modal shape in dependence of the processing parameters like screw speed, dosage, and concentration of the nanoclays. The method was verified with SEM measurements which yield comparable results. The method is suitable for industrial in-line processing monitoring of particle radii and dispersion process, respectively.

Influence of Punch Geometry on Process Parameters in Cold Backward Extrusion

NASA Astrophysics Data System (ADS)

Plančak, M.; Barišić, B.; Car, Z.; Movrin, D.

2011-01-01

In cold extrusion of steel tools make direct contact with the metal to be extruded. Those tools are exposed to high contact stresses which, in certain cases, may be limiting factors in applying this technology. The present paper was bound to the influence of punch head design on radial stress at the container wall in the process of cold backward extrusion. Five different punch head geometries were investigated. Radial stress on the container wall was measured by pin load cell technique. Special tooling for the experimental investigation was designed and made. Process has been analyzed also by FE method. 2D models of tools were obtained by UGS NX and for FE analysis Simufact Forming GP software was used. Obtained results (experimental and obtained by FE) were compared and analyzed. Optimal punch head geometry has been suggested.

A data mining approach to optimize pellets manufacturing process based on a decision tree algorithm.

PubMed

Ronowicz, Joanna; Thommes, Markus; Kleinebudde, Peter; Krysiński, Jerzy

2015-06-20

The present study is focused on the thorough analysis of cause-effect relationships between pellet formulation characteristics (pellet composition as well as process parameters) and the selected quality attribute of the final product. The shape using the aspect ratio value expressed the quality of pellets. A data matrix for chemometric analysis consisted of 224 pellet formulations performed by means of eight different active pharmaceutical ingredients and several various excipients, using different extrusion/spheronization process conditions. The data set contained 14 input variables (both formulation and process variables) and one output variable (pellet aspect ratio). A tree regression algorithm consistent with the Quality by Design concept was applied to obtain deeper understanding and knowledge of formulation and process parameters affecting the final pellet sphericity. The clear interpretable set of decision rules were generated. The spehronization speed, spheronization time, number of holes and water content of extrudate have been recognized as the key factors influencing pellet aspect ratio. The most spherical pellets were achieved by using a large number of holes during extrusion, a high spheronizer speed and longer time of spheronization. The described data mining approach enhances knowledge about pelletization process and simultaneously facilitates searching for the optimal process conditions which are necessary to achieve ideal spherical pellets, resulting in good flow characteristics. This data mining approach can be taken into consideration by industrial formulation scientists to support rational decision making in the field of pellets technology. Copyright © 2015 Elsevier B.V. All rights reserved.

Method of manufacturing superconductor wire

DOEpatents

Motowidlo, Leszek

2014-09-16

A method for forming Nb.sub.3Sn superconducting wire is provided. The method employs a powder-in-tube process using a high-tin intermetallic compound, such as MnSn.sub.2, for producing the Nb.sub.3Sn. The use of a high-tin intermetallic compound enables the process to perform hot extrusion without melting the high-tin intermetallic compound. Alternatively, the method may entail drawing the wire without hot extrusion.

Consumer acceptance and aroma characterization of navy bean (Phaseolus vulgaris) powders prepared by extrusion and conventional processing methods.

PubMed

Szczygiel, Edward J; Harte, Janice B; Strasburg, Gale M; Cho, Sungeun

2017-09-01

Food products produced with bean ingredients are gaining in popularity among consumers due to the reported health benefits. Navy bean (Phaseolus vulgaris) powder produced through extrusion can be considered as a resource-efficient alternative to conventional methods, which often involve high water inputs. Therefore, navy bean powders produced with extrusion and conventional methods were assessed for the impact of processing on consumer liking in end-use products and odor-active compounds. Consumer acceptance results reveal significant differences in flavor, texture and overall acceptance scores of several products produced with navy bean powder. Crackers produced with extruded navy bean powder received higher hedonic flavor ratings than those produced with commercial navy bean powder (P < 0.001). GC-O data showed that the commercial powder produced through conventional processing had much greater contents of several aliphatic aldehydes commonly formed via lipid oxidation, such as hexanal, octanal and nonanal with descriptors of 'grassy', 'nutty', 'fruity', 'dusty', and 'cleaner', compared to the extruded powder. Extrusion processed navy bean powders were preferred over commercial powders for certain navy bean powder applications. This is best explained by substantial differences in aroma profiles of the two powders that may have been caused by lipid oxidation. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Reactive Extrusion of Zein with Glyoxal

USDA-ARS?s Scientific Manuscript database

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...

Means of determining extrusion temperatures

DOEpatents

McDonald, Robert E.; Canonico, Domenic A.

1977-01-01

In an extrusion process comprising the steps of fabricating a metal billet, heating said billet for a predetermined time and at a selected temperature to increase its plasticity and then forcing said heated billet through a small orifice to produce a desired extruded object, the improvement comprising the steps of randomly inserting a plurality of small metallic thermal tabs at different cross sectional depths in said billet as a part of said fabricating step, and examining said extruded object at each thermal tab location for determining the crystal structure at each extruded thermal tab thus revealing the maximum temperature reached during extrusion in each respective tab location section of the extruded object, whereby the thermal profile of said extruded object during extrusion may be determined.

Friction modifier using adherent metallic multilayered or mixed element layer conversion coatings

NASA Technical Reports Server (NTRS)

Schramm, Harry F. (Inventor); Defalco, Frank G. (Inventor); Starks, Sr., Lloyd L. (Inventor)

2012-01-01

A process for creating conversion coatings and spin, drawing, and extrusion finishes for surfaces, wherein the conversion coatings and spin, drawing, and extrusion finishes contain potassium, phosphorus, nitrogen, silicon, and one or more non-alkaline metals. The process comprises forming a first aqueous solution of silicate, potassium hydroxide, and ammonium hydroxide; forming a second aqueous solution of water, phosphoric acid, ammonium hydroxide, an alkali metal hydroxide, and one or more non-alkaline metals, and then combining the first solution with the second solution to form a final solution. This final solution forms an anti-friction multi-layer conversion coating or a spin, drawing, and extrusion finish on a surface when applied to the surface, either directly or as an additive in lubricating fluids.

Friction Modifier Using Adherent Metallic Multilayered or Mixed Element Layer Conversion Coatings

NASA Technical Reports Server (NTRS)

Schramm, Harry F. (Inventor); Defalco, Francis G. (Inventor); Starks, Lloyd L., Sr. (Inventor)

2013-01-01

A process for creating conversion coatings and spin, drawing, and extrusion finishes for surfaces, wherein the conversion coatings and spin, drawing, and extrusion finishes contain potassium, phosphorus, nitrogen, and one or more non-alkaline metals and/or one or more metalloids. The process comprises forming an aqueous solution of water, phosphoric acid or sulfuric acid, ammonium hydroxide, an alkali metal hydroxide, and one or more non-alkaline metals and/or one or more metalloids. The aqueous solution forms an anti-friction multilayer conversion and/or mixed element coating or a spin, drawing, and extrusion finish on a surface when applied to the surface, either directly without the use of applied external electromotive force, or as an additive in lubricating fluids.

TOPICAL REVIEW: Monitoring of polymer melt processing

NASA Astrophysics Data System (ADS)

Alig, Ingo; Steinhoff, Bernd; Lellinger, Dirk

2010-06-01

The paper reviews the state-of-the-art of in-line and on-line monitoring during polymer melt processing by compounding, extrusion and injection moulding. Different spectroscopic and scattering techniques as well as conductivity and viscosity measurements are reviewed and compared concerning their potential for different process applications. In addition to information on chemical composition and state of the process, the in situ detection of morphology, which is of specific interest for multiphase polymer systems such as polymer composites and polymer blends, is described in detail. For these systems, the product properties strongly depend on the phase or filler morphology created during processing. Examples for optical (UV/vis, NIR) and ultrasonic attenuation spectra recorded during extrusion are given, which were found to be sensitive to the chemical composition as well as to size and degree of dispersion of micro or nanofillers in the polymer matrix. By small-angle light scattering experiments, process-induced structures were detected in blends of incompatible polymers during compounding. Using conductivity measurements during extrusion, the influence of processing conditions on the electrical conductivity of polymer melts with conductive fillers (carbon black or carbon nanotubes) was monitored.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eshraghi, Ray

In September 2008, the U.S. Department of Energy and Martin County Economic Development Corporation entered into an agreement to further the advancement of a microtubular PEM fuel cell developed by Microcell Corporation. The overall focus of this project was on research and development related to high volume manufacturing of fuel cells and cost reduction in the fuel cell manufacturing process. The extrusion process used for the microfiber fuel cells in this project is inherently a low cost, high volume, high speed manufacturing process. In order to take advantage of the capabilities that the extrusion process provides, all subsequent manufacturing processesmore » must be enhanced to meet the extrusion line’s speed and output. Significant research and development was completed on these subsequent processes to ensure that power output and performance were not negatively impacted by the higher speeds, design changes and process improvements developed in this project. All tasks were successfully completed resulting in cost reductions, performance improvements and process enhancements in the areas of speed and quality. These results support the Department of Energy’s goal of fuel cell commercialization.« less

Rapid production of hollow SS316 profiles by extrusion based additive manufacturing

NASA Astrophysics Data System (ADS)

Rane, Kedarnath; Cataldo, Salvatore; Parenti, Paolo; Sbaglia, Luca; Mussi, Valerio; Annoni, Massimiliano; Giberti, Hermes; Strano, Matteo

2018-05-01

Complex shaped stainless steel tubes are often required for special purpose biomedical equipment. Nevertheless, traditional manufacturing technologies, such as extrusion, lack the ability to compete in a market of customized complex components because of associated expenses towards tooling and extrusion presses. To rapid manufacture few of such components with low cost and high precision, a new Extrusion based Additive Manufacturing (EAM) process, is proposed in this paper, and as an example, short stainless steel 316L complex shaped and sectioned tubes were prepared by EAM. Several sample parts were produced using this process; the dimensional stability, surface roughness and chemical composition of sintered samples were investigated to prove process competence. The results indicate that feedstock with a 316L particle content of 92.5 wt. % can be prepared with a sigma blade mixing, whose rheological behavior is fit for EAM. The green samples have sufficient strength to handle them for subsequent treatments. The sintered samples considerably shrunk to designed dimensions and have a homogeneous microstructure to impart mechanical strength. Whereas, maintaining comparable dimensional accuracy and chemical composition which are required for biomedical equipment still need iterations, a kinematic correction and modification in debinding cycle was proposed.

Quantitative analysis of mechanical force required for cell extrusion in zebrafish embryonic epithelia.

PubMed

Yamada, Sohei; Iino, Takanori; Bessho, Yasumasa; Hosokawa, Yoichiroh; Matsui, Takaaki

2017-10-15

When cells in epithelial sheets are damaged by intrinsic or extrinsic causes, they are eliminated by extrusion from the sheet. Cell extrusion, which is required for maintenance of tissue integrity, is the consequence of contraction of actomyosin rings, as demonstrated by both molecular/cellular biological experimentation and numerical simulation. However, quantitative evaluation of actomyosin contraction has not been performed because of the lack of a suitable direct measurement system. In this study, we developed a new method using a femtosecond laser to quantify the contraction force of the actomyosin ring during cell extrusion in zebrafish embryonic epithelia. In this system, an epithelial cell in zebrafish embryo is first damaged by direct femtosecond laser irradiation. Next, a femtosecond laser-induced impulsive force is loaded onto the actomyosin ring, and the contraction force is quantified to be on the order of kPa as a unit of pressure. We found that cell extrusion was delayed when the contraction force was slightly attenuated, suggesting that a relatively small force is sufficient to drive cell extrusion. Thus, our method is suitable for the relative quantitative evaluation of mechanical dynamics in the process of cell extrusion, and in principle the method is applicable to similar phenomena in different tissues and organs of various species. © 2017. Published by The Company of Biologists Ltd.

Structural centrosome aberrations sensitize polarized epithelia to basal cell extrusion.

PubMed

Ganier, Olivier; Schnerch, Dominik; Nigg, Erich A

2018-06-01

Centrosome aberrations disrupt tissue architecture and may confer invasive properties to cancer cells. Here we show that structural centrosome aberrations, induced by overexpression of either Ninein-like protein (NLP) or CEP131/AZI1, sensitize polarized mammalian epithelia to basal cell extrusion. While unperturbed epithelia typically dispose of damaged cells through apical dissemination into luminal cavities, certain oncogenic mutations cause a switch in directionality towards basal cell extrusion, raising the potential for metastatic cell dissemination. Here we report that NLP-induced centrosome aberrations trigger the preferential extrusion of damaged cells towards the basal surface of epithelial monolayers. This switch in directionality from apical to basal dissemination coincides with a profound reorganization of the microtubule cytoskeleton, which in turn prevents the contractile ring repositioning that is required to support extrusion towards the apical surface. While the basal extrusion of cells harbouring NLP-induced centrosome aberrations requires exogenously induced cell damage, structural centrosome aberrations induced by excess CEP131 trigger the spontaneous dissemination of dying cells towards the basal surface from MDCK cysts. Thus, similar to oncogenic mutations, structural centrosome aberrations can favour basal extrusion of damaged cells from polarized epithelia. Assuming that additional mutations may promote cell survival, this process could sensitize epithelia to disseminate potentially metastatic cells. © 2018 The Authors.

Study on effects of powder and flake chemistry and morphology on the properties of Al-Cu-Mg-X-X-X powder metallurgy advanced aluminum alloys

NASA Technical Reports Server (NTRS)

Meschter, P. J.; Lederich, R. J.; Oneal, J. E.; Pao, P. S.

1985-01-01

The effects of alloy chemistry and particulate morphology on consolidation behavior and consolidated product properties in rapid solidification processed, powder-metallurgical Al-3Li-1.5Cu-1Mg-0.5Co-0.2Zr and Al-4.4Cu-1.5Mg-Fe-Ni-0.2Zr extrusions and forgings were studied. Microstructures and mechanical properties of both alloys are largely unaffected by particulate production method (vacuum atomization, ultrasonic atomization, or twin-roller quenching) and by particulate solidification rates between 1000 and 100,000 K/s. Consolidation processing by canning, cold compaction, degassing, and hot extrusion is sufficient to yield mechanical properties in the non-Li-containing alloy extrusions which are similar to those of 7075-Al, but ductilities and fracture toughnesses are inferior owing to poor interparticle bonding caused by lack of a vacuum-hot-pressing step during consolidation. Mechanical properties of extrusions are superior to those of forgings owing to the stronger textures produced by the more severe hot working during extrusion. The effects on mechanical properties of dispersoid size and volume fraction, substructural refinement, solid solution strengthening by Mg, and precipitate size and distribution are elucidated for both alloy types.

Fabrication of High Strength Lightweight Metals for Armor and Structural Applications: Large Scale Equal Channel Angular Extrusion Processing of Aluminum 5083 Alloy

DTIC Science & Technology

2017-06-01

ARL-TR-8047 ● JUNE 2017 US Army Research Laboratory Fabrication of High -Strength Lightweight Metals for Armor and Structural...to the originator. ARL-TR-8047 ● JUNE 2017 US Army Research Laboratory Fabrication of High -Strength Lightweight Metals for...Fabrication of High -Strength Lightweight Metals for Armor and Structural Applications: Large-Scale Equal Channel Angular Extrusion Processing of

One-step continuous extrusion process for the manufacturing of solid dispersions.

PubMed

Maniruzzaman, M; Nair, A; Scoutaris, N; Bradley, Michael S A; Snowden, M J; Douroumis, D

2015-12-30

The purpose of this study was to evaluate the performance of synthetic magnesium aluminometasilicate (MAS) as a novel inorganic carrier in hot melt extrusion (HME) processing of indomethacin (IND) for the development of solid dispersions. A continuous extrusion process at various IND/excipient blend ratios (20%, 30% and 40%) was performed using a twin-screw extruder. Physicochemical characterization carried out by SEM, DSC, and XRPD demonstrated the presence of IND in amorphous nature within the porous network of the inorganic material for all extruded formulations. Further, AFM and FTIR studies revealed a single-phase amorphous system and intermolecular H-bonding formation. The IND/MAS extrudates showed enhanced INM dissolution rates within 100% been released within 1h. Stability studies under accelerated conditions (40°C, RH 75%) showed that MAS retained the physical stability of the amorphous solid dispersions even at high drug loadings for 12 months. Copyright © 2015 Elsevier B.V. All rights reserved.

Recycle of mixed automotive plastics: A model study

NASA Astrophysics Data System (ADS)

Woramongconchai, Somsak

This research investigated blends of virgin automotive plastics which were identified through market analysis. The intent was that this study could be used as a basis for further research in blends of automotive plastics recyclate. The effects of temperature, shear, time, and degree of mixing in a two-roll mill, a single-screw extruder, and a twin-screw extruder were investigated. Properties were evaluated in terms of melt flow, rigidity, strength, impact, heat resistance, electrical resistivity, color, and resistance to water and gasoline. Torque rheometry, dynamic mechanical analysis (DMA), optical and scanning electron microscopy were used to characterize the processability and morphology of major components of the blends. The two-roll mill was operated at high temperature, short time, and low roll speed to avoid discolored and degraded materials. The single-screw extruder and twin-screw extruder were operated at medium and high temperature and high screw speed, respectively, for optimizing head pressure, residence time, shear and degree of mixing of the materials. Melt index increased with extrusion temperature. Flexural modulus increased with the processing temperatures in milling or twin-screw extrusion, but decreased with the increasing single-screw extrusion temperature. Tensile modulus was also enhanced by increasing processing temperature. The tensile strengths for each process were similar and relatively low. The impact strength increased with temperature and roll speed in two-roll milling, was unaffected by the single-screw extrusion temperature and decreased with increasing twin-screw extrusion temperature. Heat resistance was always reduced by higher processing temperature. The volume resistivity increased, water absorption was unaffected and gasoline absorption altered by increased processing temperature. The latter increased somewhat with mill temperature, roll speed (two-roll mill) and higher extrusion temperature (single-screw extruder), but decreased with increased twin-screw extrusion temperature. The flexural modulus of the recycled mixed automotive plastics expected in 2003 was higher than the 1980s and 1990 recycle. Flexural strength effects were not large enough for serious consideration, but were more dominant when compared to those in the 1980s and 1990s. Impact strengths at 20-30 J/m were the lowest value compared to the 1980s and 1990s mixed automotive recycle. Torque rheometry, dynamic mechanical analysis and optical and electron microscopy agreed with each other on the characterization of the processability and morphology of the blends. LLDPE and HDPE were miscible while PP was partially miscible with polyethylene. ABS and nylon-6 were immiscible with the polyolefins, but partially miscible with each other. As expected, the polyurethane foam was immiscible with the other components. The minor components of the model recycle of mixed automotive materials were probably partially miscible with ABS/nylon-6, but there were multiple and unresolved phases in the major blends.

Equal channel angular extrusion for bulk processing of Fe–Co–2V soft magnetic alloys, part II: Texture analysis and magnetic properties

DOE PAGES

Kustas, Andrew B.; Michael, Joseph R.; Susan, Don F.; ...

2018-06-04

In Part I, equal channel angular extrusion (ECAE) was demonstrated as a novel, simple-shear deformation process for producing bulk forms of the low ductility Fe–Co–2V (Hiperco 50A®) soft ferromagnetic alloy with refined grain sizes. Microstructures and mechanical properties were discussed. In this Part II contribution, the crystallographic textures and quasi-static magnetic properties of ECAE-processed Hiperco were characterized. The textures were of a simple-shear character defined by partial {110} and <111> fibers inclined relative to the extrusion direction, in agreement with the expectations for simple-shear deformation textures of BCC metals. These textures were observed throughout all processing conditions and only slightlymore » reduced in intensity by subsequent recrystallization heat treatments. Characterization of the magnetic properties revealed a lower coercivity and higher permeability for ECAE-processed Hiperco specimens relative to the conventionally processed and annealed Hiperco bar. In conclusion, the effects of the resultant microstructure and texture on the coercivity and permeability magnetic properties are discussed.« less

Equal channel angular extrusion for bulk processing of Fe–Co–2V soft magnetic alloys, part II: Texture analysis and magnetic properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kustas, Andrew B.; Michael, Joseph R.; Susan, Don F.

In Part I, equal channel angular extrusion (ECAE) was demonstrated as a novel, simple-shear deformation process for producing bulk forms of the low ductility Fe–Co–2V (Hiperco 50A®) soft ferromagnetic alloy with refined grain sizes. Microstructures and mechanical properties were discussed. In this Part II contribution, the crystallographic textures and quasi-static magnetic properties of ECAE-processed Hiperco were characterized. The textures were of a simple-shear character defined by partial {110} and <111> fibers inclined relative to the extrusion direction, in agreement with the expectations for simple-shear deformation textures of BCC metals. These textures were observed throughout all processing conditions and only slightlymore » reduced in intensity by subsequent recrystallization heat treatments. Characterization of the magnetic properties revealed a lower coercivity and higher permeability for ECAE-processed Hiperco specimens relative to the conventionally processed and annealed Hiperco bar. In conclusion, the effects of the resultant microstructure and texture on the coercivity and permeability magnetic properties are discussed.« less

Continuous manufacturing of solid lipid nanoparticles by hot melt extrusion.

PubMed

Patil, Hemlata; Kulkarni, Vijay; Majumdar, Soumyajit; Repka, Michael A

2014-08-25

Solid lipid nanoparticles (SLN) can either be produced by hot homogenization of melted lipids at higher temperatures or by a cold homogenization process. This paper proposes and demonstrates the formulation of SLN for pharmaceutical applications by combining two processes: hot melt extrusion (HME) technology for melt-emulsification and high-pressure homogenization (HPH) for size reduction. This work aimed at developing continuous and scalable processes for SLN by mixing a lipid and aqueous phase containing an emulsifier in the extruder barrel at temperatures above the melting point of the lipid and further reducing the particle size of emulsion by HPH linked to HME in a sequence. 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 (for 60 mg/ml lipid solution at a flow rate of 100ml/min). Among the several process parameters investigated, the lipid concentration, residence time and screw design played major roles in influencing the size of the SLN. This new process demonstrates the potential use of hot melt extrusion technology for continuous and large-scale production of SLN. Copyright © 2014 Elsevier B.V. All rights reserved.

LINER FOR EXTRUSION BILLET CONTAINERS. Interim Technical Documentary Progress Report, May 4-August 4, 1963

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spachner, S.A.

1964-10-31

Rokide-process alumina and zirconia coatings and a Udimet 700 superalloy liner were evaluated by extrusion of 31/2-in. billets of Inconel 713C, Udimet 700, SAE 4340, PH15--7Mo, and TZM alloys, using rod extrusion dies of temperatures were in the 1900 to 2250 deg F and 2900 to 3600 deg F ranges. Both alumina and zirconia coatings provided adequate protection to the support tooling at temperatures to 3450 deg F. Alumina coatings showed wear at temperatures over 2900 deg F, but may be serviceable to 3450 deg F. Zirconia coatings showed erratic results. One coating did withstand extrusion at 3450 deg Fmore » without apparent wear. The Udimet 700 liner did not show wear at 2000 deg F, but did react with the TZM billet at 3600 deg F. T-section die design was modified to prevent die cracking during extrusion and reduce coating grinding costs. (auth)« less

Autophagy can promote but is not required for epithelial cell extrusion in the amnioserosa of the Drosophila embryo.

PubMed

Cormier, Olga; Mohseni, Nilufar; Voytyuk, Iryna; Reed, Bruce H

2012-02-01

During Drosophila embryogenesis the majority of the extra-embryonic epithelium known as the amnioserosa (AS) undergoes programmed cell death (PCD) following the completion of the morphogenetic process of dorsal closure. Approximately ten percent of AS cells, however, are eliminated during dorsal closure by extrusion from the epithelium. Using biosensors that report autophagy and caspase activity in vivo, we demonstrate that AS cell extrusion occurs in the context of elevated autophagy and caspase activation. Furthermore, we evaluate AS extrusion rates, autophagy, and caspase activation in embryos in which caspase activity or autophagy are altered by genetic manipulation. This includes using the GAL4/UAS system to drive expression of p35, reaper, dINR (ACT) and Atg1 in the AS; we also analyze embryos lacking both maternal and zygotic expression of Atg1. Based on our results we suggest that autophagy can promote, but is not required for, epithelial extrusion and caspase activation in the amnioserosa.

Experimental laboratory measurement of thermophysical properties of selected coal types

NASA Technical Reports Server (NTRS)

Lloyd, W. G.

1979-01-01

A number of bituminous coals of moderate to high plasticity were examined, along with portions of their extrudates from the JPL 1.5-inch 850 F screw extruder. Portions of the condensed pyrolysis liquids released during extrusion, and of the gaseous products formed during extrusion were also analyzed. In addition to the traditional determinations, the coals and extrudates were examined in terms of microstructure (especially extractable fractions), thermal analysis (especially that associated with the plastic state), and reactivity towards thermal and catalyzed hydroliquefaction. The process of extrusion increases the fixed carbon content of coals by about 5% and tends to increase the surface area. Coals contaning 25% or more DMF-extractable material show an increase in extractables as a result of extrusion; those initially containing less than 20% extractables show a decrease as a result of extrusion. Both the raw and extruded samples of Kentucky #9 coal are highly reactive towards hydroliquefaction, undergoing conversions of 75 to 80% in 15 min and 85-94% in 60 min in a stirred clave.

Deformed soft matter under constraints

NASA Astrophysics Data System (ADS)

Bertrand, Martin

In the last few decades, an increasing number of physicists specialized in soft matter, including polymers, have turned their attention to biologically relevant materials. The properties of various molecules and fibres, such as DNA, RNA, proteins, and filaments of all sorts, are studied to better understand their behaviours and functions. Self-assembled biological membranes, or lipid bilayers, are also the focus of much attention as many life processes depend on these. Small lipid bilayers vesicles dubbed liposomes are also frequently used in the pharmaceutical and cosmetic industries. In this thesis, work is presented on both the elastic properties of polymers and the response of lipid bilayer vesicles to extrusion in narrow-channels. These two areas of research may seem disconnected but they both concern deformed soft materials. The thesis contains four articles: the first presenting a fundamental study of the entropic elasticity of circular chains; the second, a simple universal description of the effect of sequence on the elasticity of linear polymers such as DNA; the third, a model of the symmetric thermophoretic stretch of a nano-confined polymer; the fourth, a model that predicts the final sizes of vesicles obtained by pressure extrusion. These articles are preceded by an extensive introduction that covers all of the essential concepts and theories necessary to understand the work that has been done.

Continuous coal processing method

NASA Technical Reports Server (NTRS)

Ryason, P. R. (Inventor)

1980-01-01

A coal pump is provided in which solid coal is heated in the barrel of an extruder under pressure to a temperature at which the coal assumes plastic properties. The coal is continuously extruded, without static zones, using, for example, screw extrusion preferably without venting through a reduced diameter die to form a dispersed spray. As a result, the dispersed coal may be continuously injected into vessels or combustors at any pressure up to the maximum pressure developed in the extrusion device. The coal may be premixed with other materials such as desulfurization aids or reducible metal ores so that reactions occur, during or after conversion to its plastic state. Alternatively, the coal may be processed and caused to react after extrusion, through the die, with, for example, liquid oxidizers, whereby a coal reactor is provided.

Single screw extrusion of apple pomace-enriched blends: Extrudate characteristics and determination of optimum processing conditions.

PubMed

Singha, Poonam; Muthukumarappan, Kasiviswanathan

2018-07-01

Response surface methodology was used to investigate the single screw extrusion of apple pomace-defatted soy flour-corn grits blends and the product properties. Five different blends at a level of 0-20% w/w apple pomace were extrusion cooked with varied barrel and die temperature (100-140℃), screw speed (100-200 rpm), and feed moisture content (14-20% wet basis). Increasing apple pomace content in the blends significantly ( P < 0.05) increased the bulk density, the total phenolic content, and the antioxidant activity of the extrudates. The expansion ratio increased with pomace inclusion level of 5% but decreased significantly ( P < 0.05) at higher levels of pomace inclusion (10-20%). Moisture content had quadratic influence on water absorption and solubility indices. Optimal extrusion cooking conditions most likely to produce apple pomace-enriched extruded snack products were at 140℃ barrel and die temperature, 20% feed moisture content, and 200 rpm screw speed. The results indicated active interaction between apple pomace and starch during expansion process.

Modeling the Formation of Transverse Weld during Billet-on-Billet Extrusion

PubMed Central

Mahmoodkhani, Yahya; Wells, Mary; Parson, Nick; Jowett, Chris; Poole, Warren

2014-01-01

A comprehensive mathematical model of the hot extrusion process for aluminum alloys has been developed and validated. The plasticity module was developed using a commercial finite element package, DEFORM-2D, a transient Lagrangian model which couples the thermal and deformation phenomena. Validation of the model against industrial data indicated that it gave excellent predictions of the pressure during extrusion. The finite element predictions of the velocity fields were post-processed to calculate the thickness of the surface cladding as one billet is fed in after another through the die (i.e., the transverse weld). The mathematical model was then used to assess the effect a change in feeder dimensions would have on the shape, thickness and extent of the transverse weld during extrusion. Experimental measurements for different combinations of billet materials show that the model is able to accurately predict the transverse weld shape as well as the clad surface layer to thicknesses of 50 μm. The transverse weld is significantly affected by the feeder geometry shape, but the effects of ram speed, billet material and temperature on the transverse weld dimensions are negligible. PMID:28788629

Continuous Ultrasonic Inspection of Extruded Wood-Plastic Composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tucker, Brian J.; Bender, Donald A.

Nondestructive evaluation (NDE) techniques are needed for in-line monitoring of wood-plastic composite (WPC) quality during manufacturing for process control. Through-transmission ultrasonic inspection is useful in characterizing stiffness and detecting cracks and voids in a range of materials; however, little is documented about ultrasound propagation in WPC materials. The objectives of this research were to determine applicable ultrasonic transducer frequencies, coupling methods, configurations and placements for wave speed monitoring and web defect detection within an extrusion process; to quantify the effects of temperature on ultrasonic parameters; and to develop a prototype ultrasonic inspection system for a full-size extrusion line. An angledmore » beam, water-coupled ultrasonic inspection system using a pair of 50-kHz narrowband transducers was adequate for monitoring wave speed parallel to the extrusion direction. For locating internal web defects, water-coupled, 500-kHz broadband ultrasonic transducers were used in a through-thickness transmission setup. Temperature compensation factors were developed to adjust ultrasonic wave speed measurements. The prototype inspection system was demonstrated in a 55 mm conical twin-screw extrusion line.« less

Effect of extrusion conditions on physicochemical and sensorial properties of corn-broad beans (Vicia faba) spaghetti type pasta.

PubMed

Giménez, M A; González, R J; Wagner, J; Torres, R; Lobo, M O; Samman, N C

2013-01-15

Corn-broad bean spaghetti type pasta was made with a corn/broad bean flour blend in a 70:30 ratio, through an extrusion-cooking process (Brabender 10 DN single-screw extruder with a 3:1 compression ratio). The effect of temperature (T=80, 90 and 100°C) and moisture (M=28%, 31% and 34%) on the extrusion responses (specific consumption of mechanical energy and pressure) and the quality of this pasta-like product (expansion, cooking-related losses, water absorption, firmness and stickiness) was assessed. The structural changes of starch were studied by means of DSC and XRD. The extrusion-cooking process, at M=28% and T=100°C, is appropriate to obtain corn-broad bean spaghetti-type pasta with high protein and dietary fibre content and adequate quality. The cooking characteristics and resistance to overcooking depended on the degree of gelatinisation and formation of amylose-lipid complexes. The critical gelatinisation point was 46.55%; beyond that point, the quality of the product declines. Copyright © 2012 Elsevier Ltd. All rights reserved.

Extrusion of metal oxide superconducting wire, tube or ribbon

DOEpatents

Dusek, Joseph T.

1993-10-05

A process for extruding a superconducting metal oxide composition YBa.sub.2 Cu.sub.3 O.sub.7-x provides a wire (tube or ribbon) having a cohesive mass and a degree of flexibility together with enhanced electrical properties. Wire diameters in the range of 6-85 mils have been produced with smaller wires on the order of 10 mils in diameter exhibiting enhanced flexibility for forming braided, or multistrand, configurations for greater current carrying capacity. The composition for extrusion contains a polymeric binder to provide a cohesive mass to bind the particles together during the extrusion process with the binder subsequently removed at lower temperatures during sintering. The composition for extrusion further includes a deflocculent, an organic plasticizer and a solvent which also are subsequently removed during sintering. Electrically conductive tubing with an inner diameter of 52 mil and an outer diameter of 87-355 mil has also been produced. Flat ribbons have been produced in the range of 10-125 mil thick by 100-500 mil wide. The superconducting wire, tube or ribbon may include an outer ceramic insulating sheath co-extruded with the wire, tubing or ribbon.

Extrusion of metal oxide superconducting wire, tube or ribbon

DOEpatents

Dusek, Joseph T.

1993-01-01

A process for extruding a superconducting metal oxide composition YBa.sub.2 Cu.sub.3 O.sub.7-x provides a wire (tube or ribbon) having a cohesive mass and a degree of flexibility together with enhanced electrical properties. Wire diameters in the range of 6-85 mils have been produced with smaller wires on the order of 10 mils in diameter exhibiting enhanced flexibility for forming braided, or multistrand, configurations for greater current carrying capacity. The composition for extrusion contains a polymeric binder to provide a cohesive mass to bind the particles together during the extrusion process with the binder subsequently removed at lower temperatures during sintering. The composition for extrusion further includes a deflocculent, an organic plasticizer and a solvent which also are subsequently removed during sintering. Electrically conductive tubing with an inner diameter of 52 mil and an outer diameter of 87-355 mil has also been produced. Flat ribbons have been produced in the range of 10-125 mil thick by 100-500 mil wide. The superconducting wire, tube or ribbon may include an outer ceramic insulating sheath co-extruded with the wire, tubing or ribbon.

Influence of Molecular Weight of Carriers and Processing Parameters on the Extrudability, Drug Release, and Stability of Fenofibrate Formulations Processed by Hot-Melt Extrusion.

PubMed

Alsulays, Bader B; Park, Jun-Bom; Alshehri, Sultan M; Morott, Joseph T; Alshahrani, Saad M; Tiwari, Roshan V; Alshetaili, Abdullah S; Majumdar, Soumyajit; Langley, Nigel; Kolter, Karl; Gryczke, Andreas; Repka, Michael A

2015-10-01

The objective of this study was to investigate the extrudability, drug release, and stability of fenofibrate (FF) formulations utilizing various hot-melt extrusion processing parameters and polyvinylpyrrolidone (PVP) polymers of various molecular weights. The different PVP grades selected for this study were Kollidon ® 12 PF (K12), Kollidon ® 30 (K30), and Kollidon ® 90 F (K90). FF was extruded with these polymers at three drug loadings (15%, 25%, and 35% w/w). Additionally, for FF combined with each of the successfully extruded PVP grades (K12 and K30), the effects of two levels of processing parameters for screw design, screw speed, and barrel temperature were assessed. It was found that the FF with (K90) was not extrudable up to 35% drug loading. With low drug loading, the polymer viscosity significantly influenced the release of FF. The crystallinity remaining was vital in the highest drug-loaded formulation dissolution profile, and the glass transition temperature of the polymer significantly affected its stability. Modifying the screw configuration resulted in more than 95% post-extrusion drug content of the FF-K30 formulations. In contrast to FF-K30 formulations, FF release and stability with K12 were significantly influenced by the extrusion temperature and screw speed.

Dimensional accuracy of aluminium extrusions in mechanical calibration

NASA Astrophysics Data System (ADS)

Raknes, Christian Arne; Welo, Torgeir; Paulsen, Frode

2018-05-01

Reducing dimensional variations in the extrusion process without increasing cost is challenging due to the nature of the process itself. An alternative approach—also from a cost perspective—is using extruded profiles with standard tolerances and utilize downstream processes, and thus calibrate the part within tolerance limits that are not achievable directly from the extrusion process. In this paper, two mechanical calibration strategies for the extruded product are investigated, utilizing the forming lines of the manufacturer. The first calibration strategy is based on global, longitudinal stretching in combination with local bending, while the second strategy utilizes the principle of transversal stretching and local bending of the cross-section. An extruded U-profile is used to make a comparison between the two methods using numerical analyses. To provide response surfaces with the FEA program, ABAQUS is used in combination with Design of Experiment (DOE). DOE is conducted with a two-level fractional factorial design to collect the appropriate data. The aim is to find the main factors affecting the dimension accuracy of the final part obtained by the two calibration methods. The results show that both calibration strategies have proven to reduce cross-sectional variations effectively form standard extrusion tolerances. It is concluded that mechanical calibration is a viable, low-cost alternative for aluminium parts that demand high dimensional accuracy, e.g. due to fit-up or welding requirements.

Hot melt extrusion of ion-exchange resin for taste masking.

PubMed

Tan, David Cheng Thiam; Ong, Jeremy Jianming; Gokhale, Rajeev; Heng, Paul Wan Sia

2018-05-30

Taste masking is important for some unpleasant tasting bioactives in oral dosage forms. Among many methods available for taste-masking, use of ion-exchange resin (IER) holds promise. IER combined with hot melt extrusion (HME) may offer additional advantages over solvent methods. IER provides taste masking by complexing with the drug ions and preventing drug dissolution in the mouth. Drug-IER complexation approaches described in literatures are mainly based either on batch processing or column eluting. These methods of drug-IER complexation have obvious limitations such as high solvent volume requirements, multiprocessing steps and extended processing time. Thus, the objective of this study was to develop a single-step, solvent-free, continuous HME process for complexation of drug-IER. The screening study evaluated drug to IER ratio, types of IER and drug complexation methods. In the screening study, a potassium salt of a weakly acidic carboxylate-based cationic IER was found suitable for the HME method. Thereafter, optimization study was conducted by varying HME process parameters such as screw speed, extrusion temperature and drug to IER ratio. It was observed that extrusion temperature and drug to IER ratio are imperative in drug-IER complexation through HME. In summary, this study has established the feasibility of a continuous complexation method for drug to IER using HME for taste masking. Copyright © 2018 Elsevier B.V. All rights reserved.

Rapid fabrication of a micro-ball lens array by extrusion for optical fiber applications.

PubMed

Shen, S C; Huang, J C

2009-07-20

Batch-fabrication of a micro-ball lens array (MBA) could not only reduce micro assembly costs but also replace conventional ball lenses or costly GRINs (Gradient Refractive Index) without compromising performance. Compared with conventional half-spherical micro-lenses, the MBA is a spherical micro-lens that can focus light in all directions, thus providing the flexibility required for optical applications. Current MBAs are made of SU-8 photoresist by an extrusion process rather than the traditional thermal reflow process. The aim of this study was to develop a new process for MBA batch-fabrication, performed at ambient temperature, by spin-coating SU-8 onto a silicon-wafer surface, which serves as an extrusion plate, and extruding it through a nozzle to form an MBA. The nozzle consists of a nozzle orifice and nozzle cavity, the former being defined and made from SU-8 photoresist using ultra-violet (UV) lithography, which results in good mechanical properties. In this paper, the fabrication of 4 x 4 MBAs with diameters ranging from 60 to 550 um is described. Optical measurements indicated a diameter variance within 3% and a maximum coupling efficiency of approximately 62% when the single mode fiber (SMF) was placed at a distance of 10 um from the MBA. The results of this study proved that MBA fabrication by the extrusion process can enhance the coupling efficiency.

A brief review of extrusion-based tissue scaffold bio-printing.

PubMed

Ning, Liqun; Chen, Xiongbiao

2017-08-01

Extrusion-based bio-printing has great potential as a technique for manipulating biomaterials and living cells to create three-dimensional (3D) scaffolds for damaged tissue repair and function restoration. Over the last two decades, advances in both engineering techniques and life sciences have evolved extrusion-based bio-printing from a simple technique to one able to create diverse tissue scaffolds from a wide range of biomaterials and cell types. However, the complexities associated with synthesis of materials for bio-printing and manipulation of multiple materials and cells in bio-printing pose many challenges for scaffold fabrication. This paper presents an overview of extrusion-based bio-printing for scaffold fabrication, focusing on the prior-printing considerations (such as scaffold design and materials/cell synthesis), working principles, comparison to other techniques, and to-date achievements. This paper also briefly reviews the recent development of strategies with regard to hydrogel synthesis, multi-materials/cells manipulation, and process-induced cell damage in extrusion-based bio-printing. The key issue and challenges for extrusion-based bio-printing are also identified and discussed along with recommendations for future, aimed at developing novel biomaterials and bio-printing systems, creating patterned vascular networks within scaffolds, and preserving the cell viability and functions in scaffold bio-printing. The address of these challenges will significantly enhance the capability of extrusion-based bio-printing. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

PubMed Central

Suriyapha, Chatkaew; Bubphachot, Bopit; Rittidech, Sampan

2015-01-01

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. PMID:26229979

Basics of Compounding: Hot Melt Extrusion.

PubMed

DePasquale, Seth

2017-01-01

Hot Melt Extrusion, a production process that has been around for quite some time, has the ability to produce innovative compounds not previously achievable with conventional methods. However, many variables need to be considered prior to production. The use of small-scale extruders and 3D printers provides compounders a pathway for developing new dosage forms at a minimal cost while initial research is being completed. This article discusses the uses of Hot Melt Extrusion, the equipment used, the current and future applications, and the challenges with the technology. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

An evaluation of the benefits of utilizing rapid solidification for development of 2XXX (Al-Cu-Mg) alloys

NASA Technical Reports Server (NTRS)

Paris, H. G.; Chellman, D. J.

1986-01-01

The advantages of rapid solidification processing over ingot metallurgy processing in the development of 2XXX aluminum alloy compositions were evaluated using a similarly processed ingot metallurgy (IM) control alloy. The powder metallurgy (PM) alloy extrusions showed a reduced age-hardening response in comparison with similar IM compositions, with higher tensile properties for naturally aged extrusions but lower properties for artificially aged ones. However, the tensile properties of naturally and artificially aged PM alloy extrusions based on a version of IM 2034 alloy, but containing 0.6 weight percent zirconium, were comparable to those of the IM control extrusions and had significantly superior combinations of strength and toughness. The tensile properties of this PM alloy showed even greater advantage in 6.4-mm (0.25-in.) and 1.8-mm (0.070-in.) plate and sheet, the yield strength being about 68 MPa (10 ksi) greater than reported values for the IM 2034 alloy sheet. An artificially aged PM alloy based on 2219 alloy also showed a strength and strength-toughness combination comparable to those of the PM Al-Cu-Mg-Zr alloy, substantially outperforming the IM 2219 alloy. These results show that rapid solidification offers the flexibility needed to modify conventional IM compositions to produce new alloy compositions with superior mechanical properties.

Dynamic recrystallization and texture evolution of Mg–Y–Zn alloy during hot extrusion process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tong, L.B.; Li, X.; Guangzhou Research Institute of Non-ferrous Metals, Guangzhou 510651

2014-06-01

The microstructure and texture evolution of Mg{sub 98.5}Y{sub 1}Zn{sub 0.5} and Mg{sub 92.5}Y{sub 5}Zn{sub 2.5} (atomic percent) alloys during hot extrusion were systematically investigated. The coarse LPSO phases with higher volume fraction (∼ 57%) suppressed the twinning generation in the initial stage of extrusion, and accelerated the dynamic recrystallization through the particle deformation zones. Therefore, the volume fraction of DRXed grains in as-extruded Mg{sub 92.5}Y{sub 5}Zn{sub 2.5} alloy was much higher than that of Mg{sub 98.5}Y{sub 1}Zn{sub 0.5} alloy. The intensive recrystallization process resulted in the conventional basal texture weakening, although the texture evolution was mainly dominated by flow behavior.more » The dynamic recrystallization behavior in Mg{sub 92.5}Y{sub 5}Zn{sub 2.5} alloy restricted the formation of deformation texture, and thus the more random texture was observed during the whole extrusion process. - Highlights: • The densely coarse LPSO phases suppressed the twinning deformation. • Coarse LPSO phases induced the particle stimulated nucleation effect. • Dynamic recrystallization resulted in the basal texture weakening effect.« less

Fate of Fusarium mycotoxins in maize flour and grits during extrusion cooking.

PubMed

Scudamore, Keith A; Guy, Robin C E; Kelleher, Brian; MacDonald, Susan J

2008-11-01

Extrusion technology is used widely in the manufacture of a range of breakfast cereals and snacks for human consumption and animal feeds. To minimise consumer exposure to mycotoxins, the levels of deoxynivalenol (DON) and zearalenone (ZON) in cereals/cereal products and fumonisins B(1) and B(2) (FB(1) and FB(2)) in maize are controlled by European Union legislation. Relatively few studies, however, have examined the loss of Fusarium mycotoxins during processing. The behaviour of FB(1), FB(2) and fumonisin B(3) (FB(3)), DON and ZON during extrusion of naturally contaminated maize flour and maize grits is examined using pilot-scale equipment. DON and ZON are relatively stable during extrusion cooking but the fumonisins are lost to varying degrees. There is some loss of ZON when present in low concentrations and extruded at higher moisture contents. The presence of additives, such as reducing sugars and sodium chloride, can also affect mycotoxin levels. Moisture content of the cereal feed during extrusion is important and has a greater effect than temperature, particularly on the loss of fumonisins at the lower moistures. The effects are complex and not easy to explain, although more energy input to the extruder is required for drier materials. However, on the basis of these studies, the relationship between the concentration of Fusarium toxins in the raw and finished product is toxin- and process-dependent.

Functionality of extrusion--texturized whey proteins.

PubMed

Onwulata, C I; Konstance, R P; Cooke, P H; Farrell, H M

2003-11-01

Whey, a byproduct of the cheesemaking process, is concentrated by processors to make whey protein concentrates (WPC) and isolates (WPI). Only 50% of whey proteins are used in foods. In order to increase their usage, texturizing WPC, WPI, and whey albumin is proposed to create ingredients with new functionality. Extrusion processing texturizes globular proteins by shearing and stretching them into aligned or entangled fibrous bundles. In this study, WPC, WPI, and whey albumin were extruded in a twin screw extruder at approximately 38% moisture content (15.2 ml/min, feed rate 25 g/min) and, at different extrusion cook temperatures, at the same temperature for the last four zones before the die (35, 50, 75, and 100 degrees C, respectively). Protein solubility, gelation, foaming, and digestibility were determined in extrudates. Degree of extrusion-induced insolubility (denaturation) or texturization, determined by lack of solubility at pH 7 for WPI, increased from 30 to 60, 85, and 95% for the four temperature conditions 35, 50, 75, and 100 degrees C, respectively. Gel strength of extruded isolates increased initially 115% (35 degrees C) and 145% (50 degrees C), but gel strength was lost at 75 and 100 degrees C. Denaturation at these melt temperatures had minimal effect on foaming and digestibility. Varying extrusion cook temperature allowed a new controlled rate of denaturation, indicating that a texturized ingredient with a predetermined functionality based on degree of denaturation can be created.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Wei; Boehlert, C. J.

The tensile properties of extruded Ti 6Al 4V xB alloys (wt.%) were evaluated in an orientation perpendicular to the extrusion direction at room-temperature and 455 C. The extrusion process preferentially oriented the basal plane of -Ti perpendicular to the extrusion axis. This strong - phase texture resulted in tensile anisotropy. The tensile strength in the transverse orientation was lower than that in the longitudinal orientation, but it remained greater than that for the ascast Ti 6Al 4V. The TiB phasewas aligned in the extrusion direction and increased B content was found to weaken the -phase texture, causing a weakening ofmore » tensile anisotropy. Debonding was not observed during the tensile tests in the transverse orientation, indicating a strong interface bond exists between the TiB phase and the two-phase ( + ) Ti 6Al 4V matrix.« less

Characterization Methods of Encapsulates

NASA Astrophysics Data System (ADS)

Zhang, Zhibing; Law, Daniel; Lian, Guoping

Food active ingredients can be encapsulated by different processes, including spray drying, spray cooling, spray chilling, spinning disc and centrifugal co-extrusion, extrusion, fluidized bed coating and coacervation (see Chap. 2 of this book). The purpose of encapsulation is often to stabilize an active ingredient, control its release rate and/or convert a liquid formulation into a solid which is easier to handle. A range of edible materials can be used as shell materials of encapsulates, including polysaccharides, fats, waxes and proteins (see Chap. 3 of this book). Encapsulates for typical industrial applications can vary from several microns to several millimetres in diameter although there is an increasing interest in preparing nano-encapsulates. Encapsulates are basically particles with a core-shell structure, but some of them can have a more complex structure, e.g. in a form of multiple cores embedded in a matrix. Particles have physical, mechanical and structural properties, including particle size, size distribution, morphology, surface charge, wall thickness, mechanical strength, glass transition temperature, degree of crystallinity, flowability and permeability. Information about the properties of encapsulates is very important to understanding their behaviours in different environments, including their manufacturing processes and end-user applications. E.g. encapsulates for most industrial applications should have desirable mechanical strength, which should be strong enough to withstand various mechanical forces generated in manufacturing processes, such as mixing, pumping, extrusion, etc., and may be required to be weak enough in order to release the encapsulated active ingredients by mechanical forces at their end-user applications, such as release rate of flavour by chewing. The mechanical strength of encapsulates and release rate of their food actives are related to their size, morphology, wall thickness, chemical composition, structure etc. Hence, reliable methods which can be used to characterize these properties of encapsulates are vital. In this chapter, the state-of-art of these methods, their principles and applications, and release mechanisms are described as follows.

Reduction of fumonisin B₁ in corn grits by twin-screw extrusion.

PubMed

Jackson, Lauren S; Jablonski, Joseph; Bullerman, Lloyd B; Bianchini, Andreia; Hanna, Milford A; Voss, Kenneth A; Hollub, April D; Ryu, Dojin

2011-08-01

This study was designed to investigate the fate of fumonisins in flaking corn grits during twin-screw extrusion by measuring fumonisin B₁ (FB₁) and its analogs with a mass balance approach. Food grade corn grits and 2 batches of grits contaminated with FB₁ at 10 and 50 μg/g by Fusarium verticillioides M-2552 were processed with or without glucose supplementation (10%, w/w) with a twin-screw extruder. Extrusion reduced FB₁ in contaminated grits by 64% to 72% without glucose and 89% to 94% with added glucose. In addition, extrusion alone resulted in 26% to 73% reduction in the levels of fumonisin B₂ and fumonisin B₃, while levels of both mycotoxins were reduced by >89% in extruded corn grits containing 10% glucose. Mass balance analysis showed that 38% to 46% of the FB₁ species detected in corn extruded with glucose was N-(deoxy-D-fructos-1-yl)-FB₁, while 23% to 37% of FB₁ species detected in extruded corn grits with and without added glucose was bound to the matrix. It was also found that the hydrolyzed form of FB₁ was a minor species in extruded corn grits with or without added glucose, representing <15% of the total FB₁ species present. Less than 46% of FB₁ originally present in corn grits could be detected in the fumonisin analogues measured in this study. Research is needed to identify the reaction products resulting from extrusion processing of fumonisin-contaminated corn products. Twin-screw extrusion is widely used in food industry for its versatility. This technology may reduce the level of fumonisins in corn particularly with added glucose. Journal of Food Science © 2011 Institute of Food Technologists® No claim to original US government works.

Integrated hot-melt extrusion - injection molding continuous tablet manufacturing platform: Effects of critical process parameters and formulation attributes on product robustness and dimensional stability.

PubMed

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

2017-10-05

This study provides a framework for robust tablet development using an integrated hot-melt extrusion-injection molding (IM) continuous manufacturing platform. Griseofulvin, maltodextrin, xylitol and lactose were employed as drug, carrier, plasticizer and reinforcing agent respectively. A pre-blended drug-excipient mixture was fed from a loss-in-weight feeder to a twin-screw extruder. The extrudate was subsequently injected directly into the integrated IM unit and molded into tablets. Tablets were stored in different storage conditions up to 20 weeks to monitor physical stability and were evaluated by polarized light microscopy, DSC, SEM, XRD and dissolution analysis. Optimized injection pressure provided robust tablet formulations. Tablets manufactured at low and high injection pressures exhibited the flaws of sink marks and flashing respectively. Higher solidification temperature during IM process reduced the thermal induced residual stress and prevented chipping and cracking issues. Polarized light microscopy revealed a homogeneous dispersion of crystalline griseofulvin in an amorphous matrix. DSC underpinned the effect of high tablet residual moisture on maltodextrin-xylitol phase separation that resulted in dimensional instability. Tablets with low residual moisture demonstrated long term dimensional stability. This study serves as a model for IM tablet formulations for mechanistic understanding of critical process parameters and formulation attributes required for optimal product performance. Copyright © 2017 Elsevier B.V. All rights reserved.

Influences of die channel angles on microstructures and wear behaviors of AZ61 wrought magnesium alloy fabricated by extrusion-shear process

NASA Astrophysics Data System (ADS)

Hu, Hong-J.; Sun, Z.; Ou, Z.-W.

2016-12-01

Extrusion-shear (ES) process for magnesium alloy is a newly developed plastic deformation process, and ES process combines direct extrusion and two steps of ECAE (equal channel angular extrusion). To investigate the effects of the die channel angles on the microstructures and wear behaviors of AZ61 wrought magnesium alloy, the samples used in this study were fabricated by ES process with different die channel angles (120° and 135°). The microstructures of the samples were characterized by optical microscopy (OM), X-ray diffraction (XRD) and (SEM). The cumulative strains in the ES process were predicted by approaches of numerical simulation and theoretical calculation. To characterize the wear resistance of the samples, pin-on-disk tests under dry sliding conditions with various normal loads and reciprocating frequencies were conducted. To define the wear mechanisms of AZ61 magnesium alloy, the worn surfaces after wear tests were analyzed by SEM and energy-dispersive X-ray spectrometer (EDS). Based on the results obtained, die channel angles have significant influences on the grain refinements and wear behaviors of the samples. Decreasing channel angles of the ES die will not only refine the microstructures of magnesium alloys effectively and improve their harnesses, but also improve their wear resistance as decreasing channel angles results in higher friction coefficients and wear rates. With the increase in applied loads and frequencies, wear mechanisms change from mild wear (adhesion, abrasion and oxidation) to severe wear (delamination, plastic deformation and melting). In summary, the wear resistance of ES-processed AZ61 magnesium alloy could be improved by decreasing channel angles of ES dies.

Unstructured Grids for Sonic Boom Analysis and Design

NASA Technical Reports Server (NTRS)

Campbell, Richard L.; Nayani, Sudheer N.

2015-01-01

An evaluation of two methods for improving the process for generating unstructured CFD grids for sonic boom analysis and design has been conducted. The process involves two steps: the generation of an inner core grid using a conventional unstructured grid generator such as VGRID, followed by the extrusion of a sheared and stretched collar grid through the outer boundary of the core grid. The first method evaluated, known as COB, automatically creates a cylindrical outer boundary definition for use in VGRID that makes the extrusion process more robust. The second method, BG, generates the collar grid by extrusion in a very efficient manner. Parametric studies have been carried out and new options evaluated for each of these codes with the goal of establishing guidelines for best practices for maintaining boom signature accuracy with as small a grid as possible. In addition, a preliminary investigation examining the use of the CDISC design method for reducing sonic boom utilizing these grids was conducted, with initial results confirming the feasibility of a new remote design approach.

The development of poly(vinyl chloride) [PVC] extrusions for a 14,000-ton self-supporting structure for the detection of neutrinos

DOE PAGES

Grudzinski, James J.; Talaga, Richard L.; Pla-Dalmau, Anna; ...

2014-12-16

The NOvA Neutrino Experiment has built a one of a kind self-supporting plastic structure, potentially the largest ever built. The PVC structure serves as a neutrino detector and is composed of 28 individual blocks that measure 15.5 m (51 feet) high by 15.5 m (51 feet) wide by 2.1 m (7 feet) deep. The primary parts in the detector construction are 15.5m (51 foot), 15-cell PVC extrusions. These extrusions from the basis of the detector modules which are laminated together in a crossed pattern to form the individual blocks and then filled with mineral oil based liquid scintillator. The self-supportingmore » nature of the detector places important structural requirements on both the PVC formulation and the extrusions. Block assembly requirements impose narrow geometric tolerances. Due to the method of detecting neutrinos, the extrusions must possess exceptionally high reflectivity over a particular wavelength range. The requirement places additional restrictions on the components of the PVC formulation. Altogether, the PVC extrusions have to maintain important reflectivity characteristics, provide structural support to the detector, and meet relatively tight geometric requirements for assembly. In order to meet these constraints, a custom PVC formulation had to be created and extruded. Here, we describe the purpose and requirements of the NOvA detector leading to the production of our unique PVC extrusion, summarize the R&D process, and discuss the lessons learned.« less

Simulation and Analysis of One-time Forming Process of Automobile Steering Ball Head

NASA Astrophysics Data System (ADS)

Shi, Peicheng; Zhang, Xujun; Xu, Zengwei; Zhang, Rongyun

2018-03-01

Aiming at the problems such as large machining allowance, low production efficiency and material waste during die forging of ball pin, the cold extrusion process of ball head was studied and the analog simulation of the forming process was carried out by using the finite element analysis software DEFORM-3D. Through the analysis of the equivalent stress strain, velocity vector field and load-displacement curve, the flow regularity of the metal during the cold extrusion process of ball pin was clarified, and possible defects during the molding were predicted. The results showed that this process could solve the forming problem of ball pin and provide theoretical basis for actual production of enterprises.

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

PubMed

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.

Microstructure characterization of LAE442 magnesium alloy processed by extrusion and ECAP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Minárik, Peter; Král, Robert; Pešička, Josef

2016-02-15

The magnesium alloy LAE442 was processed by extrusion and equal channel angular pressing (ECAP) to achieve ultrafine grained microstructure. Detailed characterization of the microstructure was performed by scanning electron microscope, electron back scattered diffraction (EBSD) and transmission electron microscope. The initial, as-cast, microstructure consisted of large grains of ~ 1 mm. The grain refinement due to the processing by severe plastic deformation led to a decrease of the average grain size to ~ 1.7 μm after the final step of ECAP. A detailed characterization of secondary phases showed the precipitation of Al{sub 11}RE{sub 3}, Al{sub 2}Ca and Al{sub 10}RE{sub 2}Mn{submore » 7} intermetallic phases. X-ray diffraction measurements proved that Li is dissolved within the magnesium matrix in the as-cast condition. Newly formed Al{sub 3}Li phase was observed after ECAP. The texture formation due to the extrusion and ECAP was different from that in the other magnesium alloys due to the activation of non-basal slip systems as a result of the decrease of the c/a ratio. - Highlights: • Combined extrusion and equal channel angular pressing results in significant grain refinement by factor 1000 approximately. • Al{sub 11}RE{sub 3}, Al{sub 2}Ca and Al{sub 10}RE{sub 2}Mn{sub 7} secondary phases are present in the as-cast material while Li was dissolved in the Mg matrix. • Extrusion and ECAP have no effect on the composition of the secondary phases but they influence strongly their distribution. • Texture evolution is affected by decrease of c/a ratio due to the presence of Li and resulting activation of non-basal slip.« less

Quality by Design (QbD) Approach for Development of Co-Processed Excipient Pellets (MOMLETS) By Extrusion-Spheronization Technique.

PubMed

Patel, Hetal; Patel, Kishan; Tiwari, Sanjay; Pandey, Sonia; Shah, Shailesh; Gohel, Mukesh

2016-01-01

Microcrystalline cellulose (MCC) is an excellent excipient for the production of pellets by extrusion spheronization. However, it causes slow release rate of poorly water soluble drugs from pellets. Co-processed excipient prepared by spray drying (US4744987; US5686107; WO2003051338) and coprecipitation technique (WO9517831) are patented. The objective of present study was to develop co-processed MCC pellets (MOMLETS) by extrusion-spheronization technique using the principle of Quality by Design (QbD). Co-processed excipient core pellets (MOMLETS) were developed by extrusion spheronization technique using Quality by Design (QbD) approach. BCS class II drug (telmisartan) was layered onto it in a fluidized bed processor. Quality Target Product Profile (QTPP) and Critical Quality Attributes (CQA) for pellets were identified. Risk assessment was reported using Ishikawa diagram. Plackett Burman design was used to check the effect of seven independent variables; superdisintegrant, extruder speed, ethanol: water, spheronizer speed, extruder screen, pore former and MCC: lactose; on percentage drug release at 30 min. Pareto chart and normal probability plot was constructed to identify the significant factors. Box-Behnken design (BBD) using three most significant factors (Extruder screen size, type of superdisintegrant and type of pore former) was used as an optimization design. The control space was identified in which desired quality of the pellets can be obtained. Co-processed excipient core pellets (MOMLETS) were successfully developed by QbD approach. Versatility, Industrial scalability and simplicity are the main features of the proposed research. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Application of hot melt extrusion for improving bioavailability of artemisinin a thermolabile drug.

PubMed

Kulkarni, C; Kelly, A L; Gough, T; Jadhav, V; Singh, K K; Paradkar, A

2018-02-01

Hot melt extrusion has been used to produce a solid dispersion of the thermolabile drug artemisinin. Formulation and process conditions were optimized prior to evaluation of dissolution and biopharmaceutical performance. Soluplus ® , a low T g amphiphilic polymer especially designed for solid dispersions enabled melt extrusion at 110 °C although some drug-polymer incompatibility was observed. Addition of 5% citric acid as a pH modifier was found to suppress the degradation. The area under plasma concentration time curve (AUC 0-24h ) and peak plasma concentration (C max ) were four times higher for the modified solid dispersion compared to that of pure artemisinin.

Recent progress in online ultrasonic process monitoring

NASA Astrophysics Data System (ADS)

Wen, Szu-Sheng L.; Chen, Tzu-Fang; Ramos-Franca, Demartonne; Nguyen, Ky T.; Jen, Cheng-Kuei; Ihara, Ikuo; Derdouri, A.; Garcia-Rejon, Andres

1998-03-01

On-line ultrasonic monitoring of polymer co-extrusion and gas-assisted injection molding are presented. During the co- extrusion of high density polyethylene and Santoprene ultrasonic sensors consisting of piezoelectric transducers and clad ultrasonic buffer rods are used to detect the interface between these two polymers and the stability of the extrusion. The same ultrasonic sensor also measures the surface temperature of the extruded polymer. The results indicate that temperature measurements using ultrasound have a faster response time than those obtained by conventional thermocouple. In gas-assisted injection molding the polymer and gas flow front positions are monitored simultaneously. This information may be used to control the plunger movement.

Microfabrication of three-dimensional filters for liposome extrusion

NASA Astrophysics Data System (ADS)

Baldacchini, Tommaso; Nuñez, Vicente; LaFratta, Christopher N.; Grech, Joseph S.; Vullev, Valentine I.; Zadoyan, Ruben

2015-03-01

Liposomes play a relevant role in the biomedical field of drug delivery. The ability of these lipid vesicles to encapsulate and transport a variety of bioactive molecules has fostered their use in several therapeutic applications, from cancer treatments to the administration of drugs with antiviral activities. Size and uniformity are key parameters to take into consideration when preparing liposomes; these factors greatly influence their effectiveness in both in vitro and in vivo experiments. A popular technique employed to achieve the optimal liposome dimension (around 100 nm in diameter) and uniform size distribution is repetitive extrusion through a polycarbonate filter. We investigated two femtosecond laser direct writing techniques for the fabrication of three-dimensional filters within a microfluidics chip for liposomes extrusion. The miniaturization of the extrusion process in a microfluidic system is the first step toward a complete solution for lab-on-a-chip preparation of liposomes from vesicles self-assembly to optical characterization.

Development of poloxamer gel formulations via hot-melt extrusion technology.

PubMed

Mendonsa, Nicole S; Murthy, S Narasimha; Hashemnejad, Seyed Meysam; Kundu, Santanu; Zhang, Feng; Repka, Michael A

2018-02-15

Poloxamer gels are conventionally prepared by the "hot" or the "cold" process. But these techniques have some disadvantages such as high energy consumption, requires expensive equipment and often have scale up issues. Therefore, the objective of this work was to develop poloxamer gels by hot-melt extrusion technology. The model drug selected was ketoprofen. The formulations developed were 30% and 40% poloxamer gels. Of these formulations, the 30% poloxamer gels were selected as ideal gels. DSC and XRD studies showed an amorphous nature of the drug after extrusion. It was observed from the permeation studies that with increasing poloxamer concentration, a decrease in drug permeation was obtained. Other studies conducted for the formulations included in-vitro release studies, texture analysis, rheological studies and pH measurements. In conclusion, the hot-melt extrusion technology could be successfully employed to develop poloxamer gels by overcoming the drawbacks associated with the conventional techniques. Published by Elsevier B.V.

Effect of Different Extrusion Parameters on Dietary Fiber in Wheat Bran and Rye Bran.

PubMed

Andersson, Annica A M; Andersson, R; Jonsäll, Anette; Andersson, Jörgen; Fredriksson, Helena

2017-06-01

Wheat bran and rye bran are mostly used as animal feed today, but their high content of dietary fiber and bioactive components are beneficial to human health. Increased use of bran as food raw material could therefore be desirable. However, bran mainly contains unextractable dietary fiber and deteriorates the sensory properties of products. Processing by extrusion could increase the extractability of dietary fiber and increase the sensory qualities of bran products. Wheat bran and rye bran were therefore extruded at different levels of moisture content, screw speed and temperature, in order to find the optimal setting for increased extractability of dietary fiber and positive sensory properties. A water content of 24% for wheat bran and 30% for rye bran, a screw speed of 400 rpm, and a temperature of 130 °C resulted in the highest extractability of total dietary fiber and arabinoxylan. Arabinoxylan extractability increased from 5.8% in wheat bran to 9.0% in extruded wheat bran at those settings, and from 14.6% to 19.2% for rye bran. Total contents of dietary fiber and arabinoxylan were not affected by extrusion. Content of β-glucan was also maintained during extrusion, while its molecular weight decreased slightly and extractability increased slightly. Extrusion at these settings is therefore a suitable process for increasing the use of wheat bran and rye bran as a food raw material. © 2017 Institute of Food Technologists®.

Analysis of a GC/MS thermal desorption system with simultaneous sniffing for determination of off-odor compounds and VOCs in fumes formed during extrusion coating of low-density polyethylene.

PubMed

Villberg, K; Veijanen, A

2001-03-01

A thermal desorption equipment introducing volatile organic compounds (VOCs) into the gas chromatographic/ mass spectrometric system (GC/MS) with simultaneous sniffing (SNIFF) is a suitable method for identifying the volatile organic off-odor compounds formed during the extrusion coating process of low-density polyethylene. Fumes emitted during the extrusion coating process of three different plastic materials were collected at two different temperatures (285 and 315 degrees C) from an outgoing pipe and near an extruder. The VOCs of fumes were analyzed by drawing a known volume of air through the adsorbent tube filled with a solid adsorbent (Tenax GR). The air samples were analyzed by using a special thermal desorption device and GC/MS determination. The simultaneous sniffing was carried out to detect off-odors and to assist in the identification of those compounds that contribute to tainting and smelling. The amounts of off-odor carbonyl compounds and the total content of the volatile organic compounds were determined. The most odorous compounds were identified as carboxylic acids while the majority of the volatile compounds were hydrocarbons. The detection and quantification of carboxylic acids were based on the characteristic ions of their mass spectra. The higher the extrusion temperature the more odors were detected. An important observation was that the total concentration of volatiles was dependent not only on the extrusion temperature but also on the plastic material.

Mechanochemical Synthesis of Pharmaceutical Cocrystal Suspensions via Hot Melt Extrusion: Enhancing Cocrystal Yield.

PubMed

Li, Shu; Yu, Tao; Tian, Yiwei; Lagan, Colette; Jones, David S; Andrews, Gavin P

2017-11-22

Pharmaceutical cocrystals have attracted increasing attention over the past decade as an alternative way to modify the physicochemical properties and hence improve the bioavailability of a drug, without sacrificing thermodynamic stability. Our previous work has demonstrated the viability of in-situ formation of ibuprofen/isonicotinamide cocrystal suspensions within a matrix carrier via a single-step hot-melt extrusion (HME) process. The key aim of the current work is to establish optimised processing conditions to improve cocrystal yield within extruded matrices. The solubility of each individual cocrystal component in the matrix carrier was estimated using two different methods, calculation of Hansen solubility parameters, and Flory-Huggins solution theory using melting point depression measurement, respectively. The latter was found to be more relevant to extrusion cocrystallisation because of the ability to predict miscibility across a range of temperatures. The predictions obtained from the F-H phase diagrams were verified using ternary extrusion processing. Temperatures that promote solubilisation of the parent reagents during processing, and precipitation of the newly formed cocrystal were found to be the most suitable in generating high cocrystal yields. The incorporation of intensive mixing/kneading elements to the screw configuration was also shown to significantly improve the cocrystal yield when utilising a matrix platform. This work has shown that intensive mixing in combination with appropriate temperature selection, can significantly improve the cocrystal yield within a stable and low viscosity carrier during HME processing. Most importantly, this work reports, for the very first time in the literature, the use of the F-H phase diagrams to predict the most appropriate HME processing window to drive higher cocrystal yield.

Influence of twin-screw extrusion on soluble arabinoxylans and corn fiber gum from corn fiber.

PubMed

Singkhornart, Sasathorn; Lee, Seul Gi; Ryu, Gi Hyung

2013-09-01

The effect of feed moisture content and screw speed in the extrusion process with and without chemical pretreatment of corn fiber was investigated. Different chemical pretreatment methods (NaOH and H2 SO4 solution) were compared. The improvement of reducing sugar, soluble arabinoxylans (SAX) content and the yield of corn fiber gum was measured. A high reducing sugar content was obtained in the filtrate fraction from the extruded destarched corn fiber (EDCF) with H₂SO₄ pretreatment. Feed moisture content most effectively improved both reducing sugar and SAX content of filtrate. Increasing feed moisture content and screw speed resulted in a higher SAX content in the filtrate of the EDCF with NaOH pretreatment. The SAX content of the residual solid from the EDCF with NaOH pretreatment was higher compared to H₂SO₄ pretreated and unpretreated samples and significantly increased with decreasing feed moisture content. The screw speed did not have a major impact after enzyme hydrolysis. The yield of corn fiber gum was increased by 12% using NaOH pretreatment combined with extrusion process as compared to the destarched corn fiber. The results show the great potential of the extrusion process as an effective pretreatment for disruption the lignocelluloses of corn fiber, leading to conversion of cellulose to glucose and hemicelluloses to SAX and isolation of corn fiber gum. © 2013 Society of Chemical Industry.

Influence of ECAP process on mechanical and corrosion properties of pure Mg and ZK60 magnesium alloy for biodegradable stent applications

PubMed Central

Mostaed, Ehsan; Vedani, Maurizio; Hashempour, Mazdak; Bestetti, Massimiliano

2014-01-01

Equal channel angular pressing (ECAP) was performed on ZK60 alloy and pure Mg in the temperature range 150–250 °C. A significant grain refinement was detected after ECAP, leading to an ultrafine grain size (UFG) and enhanced formability during extrusion process. Comparing to conventional coarse grained samples, fracture elongation of pure Mg and ZK60 alloy were significantly improved by 130% and 100%, respectively, while the tensile strength remained at high level. Extrusion was performed on ECAP processed billets to produce small tubes (with outer/inner diameter of 4/2.5 mm) as precursors for biodegradable stents. Studies on extruded tubes revealed that even after extrusion the microstructure and microhardness of the UFG ZK60 alloy were almost stable. Furthermore, pure Mg tubes showed an additional improvement in terms of grain refining and mechanical properties after extrusion. Electrochemical analyses and microstructural assessments after corrosion tests demonstrated two major influential factors in corrosion behavior of the investigated materials. The presence of Zn and Zr as alloying elements simultaneously increases the nobility by formation of a protective film and increase the local corrosion damage by amplifying the pitting development. ECAP treatment decreases the size of the second phase particles thus improving microstructure homogeneity, thereby decreasing the localized corrosion effects. PMID:25482411

Continuous production of itraconazole-based solid dispersions by hot melt extrusion: Preformulation, optimization and design space determination.

PubMed

Thiry, Justine; Lebrun, Pierre; Vinassa, Chloe; Adam, Marine; Netchacovitch, Lauranne; Ziemons, Eric; Hubert, Philippe; Krier, Fabrice; Evrard, Brigitte

2016-12-30

The purpose of this work was to increase the solubility and the dissolution rate of itraconazole, which was chosen as the model drug, by obtaining an amorphous solid dispersion by hot melt extrusion. Therefore, an initial preformulation study was conducted using differential scanning calorimetry, thermogravimetric analysis and Hansen's solubility parameters in order to find polymers which would have the ability to form amorphous solid dispersions with itraconazole. Afterwards, the four polymers namely Kollidon ® VA64, Kollidon ® 12PF, Affinisol ® HPMC and Soluplus ® , that met the set criteria were used in hot melt extrusion along with 25wt.% of itraconazole. Differential scanning confirmed that all four polymers were able to amorphize itraconazole. A stability study was then conducted in order to see which polymer would keep itraconazole amorphous as long as possible. Soluplus ® was chosen and, the formulation was fine-tuned by adding some excipients (AcDiSol ® , sodium bicarbonate and poloxamer) during the hot melt extrusion process in order to increase the release rate of itraconazole. In parallel, the range limits of the hot melt extrusion process parameters were determined. A design of experiment was performed within the previously defined ranges in order to optimize simultaneously the formulation and the process parameters. The optimal formulation was the one containing 2.5wt.% of AcDiSol ® produced at 155°C and 100rpm. When tested with a biphasic dissolution test, more than 80% of itraconazole was released in the organic phase after 8h. Moreover, this formulation showed the desired thermoformability value. From these results, the design space around the optimum was determined. It corresponds to the limits within which the process would give the optimized product. It was observed that a temperature between 155 and 170°C allowed a high flexibility on the screw speed, from about 75 to 130rpm. Copyright © 2016 Elsevier B.V. All rights reserved.

Biaxial extrusion of polyimide LARC-TPI and LARC-TPI blends

NASA Technical Reports Server (NTRS)

Haghighat, R. Ross; Elandjian, Lucy; Lusignea, Richard W.

1990-01-01

Biaxial films of polyimide LARC-TPI and LARC-TPI/liquid crystal polymer Xydar were extruded directly from the melt for the first time via an innovative extrusion technique. Three types of films, neat LARC-TPI, LARC-TPI/10 wt pct and 30 wt pct blends were processed as a part of this NASA-funded program. Processability was greatly enhanced by incorporating Xydar. The coefficient of thermal expansion was reduced from 34 ppm/C for the neat LARC-TPI to 15 ppm/C for the 10 wt pct Xydar blend and ultimately down to 1 to 3 ppm/C for the 30 wt pct blend films in the direction of extrusion. The maximum improvement in stiffness was realized by incorporating 10 wt pct Xydar (2.8 GPa up to 4.9 GPa). Tensile strength, however, experienced a drop as a result of Xydar addition, probably caused by inefficient mixing of the two phases.

Convergence and Extrusion Are Required for Normal Fusion of the Mammalian Secondary Palate

PubMed Central

Kim, Seungil; Lewis, Ace E.; Singh, Vivek; Ma, Xuefei; Adelstein, Robert; Bush, Jeffrey O.

2015-01-01

The fusion of two distinct prominences into one continuous structure is common during development and typically requires integration of two epithelia and subsequent removal of that intervening epithelium. Using confocal live imaging, we directly observed the cellular processes underlying tissue fusion, using the secondary palatal shelves as a model. We find that convergence of a multi-layered epithelium into a single-layer epithelium is an essential early step, driven by cell intercalation, and is concurrent to orthogonal cell displacement and epithelial cell extrusion. Functional studies in mice indicate that this process requires an actomyosin contractility pathway involving Rho kinase (ROCK) and myosin light chain kinase (MLCK), culminating in the activation of non-muscle myosin IIA (NMIIA). Together, these data indicate that actomyosin contractility drives cell intercalation and cell extrusion during palate fusion and suggest a general mechanism for tissue fusion in development. PMID:25848986

Detrital zircon provenance evidence for large-scale extrusion along the Altyn Tagh fault

USGS Publications Warehouse

Yue, Y.; Graham, S.A.; Ritts, B.D.; Wooden, J.L.

2005-01-01

The question of whether or not the Altyn Tagh fault is a large-scale extrusion boundary is critical for understanding the role of lateral extrusion in accommodating the Indo-Asian convergence and in building the Tibetan Plateau. Oligocene conglomerate clasts in the eastern Xorkol basin are low-grade slate, phyllite, sandstone, dacite and carbonate, and associated paleocurrent indicators evince sediment derivation from the opposing side of the Altyn Tagh fault. Matching these clasts with similar basement rocks in the North Qilian and Tuolainanshan terranes requires post-Oligocene left-lateral offset of 380 ?? 60 km on the eastern segment of the Altyn Tagh fault, suggesting large-scale extrusion along the fault in the Cenozoic (Yue, Y.J., Ritts, B.D., Graham, S.A., 2001b. Initiation and long-term slip history of the Altyn Tagh fault. International Geological Review 43, 1087-1094.). In order to further define this piercing point, the detrital zircon pattern of Oligocene sandstone from the Xorkol basin and the zircon ages of basement on the southern side of the fault were established by ion microprobe dating. Characterized by strong peaks between 850 and 950 Ma and the absence of Paleozoic and Mesozoic ages, the detrital zircon age pattern of the Oligocene sandstone matches the age distribution of zircon-bearing rocks of the Tuolainanshan terrane. This match requires 360 ?? 40 km of post-Oligocene left-lateral displacement on the eastern segment of the Altyn Tagh fault, supporting as well as refining the previously reported lithology-based cross-fault match. At least one of the following three extrusion scenarios must have existed to accommodate this large offset: (1) northeastward extrusion along the Altyn Tagh-Alxa-East Mongolia fault, (2) eastward extrusion along the Altyn Tagh-North Qilian-Haiyuan fault, and (3) northeastward extrusion of northern Tibet as a Himalaya-scale thrust sheet along the North Qilian-Haiyuan fault. We prefer the first scenario inasmuch as rapidly growing evidence for Cenozoic strike-slip activity on the Alxa-East Mongolia fault and mid-Miocene exhumation of northern Tibet supports it. ?? 2005 Elsevier B.V. All rights reserved.

Crystal Structure of a Plant Multidrug and Toxic Compound Extrusion Family Protein.

PubMed

Tanaka, Yoshiki; Iwaki, Shigehiro; Tsukazaki, Tomoya

2017-09-05

The multidrug and toxic compound extrusion (MATE) family of proteins consists of transporters responsible for multidrug resistance in prokaryotes. In plants, a number of MATE proteins were identified by recent genomic and functional studies, which imply that the proteins have substrate-specific transport functions instead of multidrug extrusion. The three-dimensional structure of eukaryotic MATE proteins, including those of plants, has not been reported, preventing a better understanding of the molecular mechanism of these proteins. Here, we describe the crystal structure of a MATE protein from the plant Camelina sativa at 2.9 Å resolution. Two sets of six transmembrane α helices, assembled pseudo-symmetrically, possess a negatively charged internal pocket with an outward-facing shape. The crystal structure provides insight into the diversity of plant MATE proteins and their substrate recognition and transport through the membrane. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison of Extruder Systems for 3D Printer Filament Fabrication

NASA Astrophysics Data System (ADS)

Ramirez, Adriana

Additive Manufacturing (AM) has grown in popularity over the past thirty years, due to its versatility, short design to product cycle, and capability to fabricate complex geometries, which cannot otherwise be produced. There exist several platforms that are able to print objects composed of different materials, making this technology significant in different fields such as: automotive, aerospace, medical, electronics, amongst others. Though several types of AM technologies are available, the expiration of the patents on fused deposition modeling (FDM) in 2009 has led to a widespread use of this platform in academia and home use settings. Widespread use of FDM-type AM platforms has led to a demand to fabricate feedstock materials for this AM platform. Particularly, in the home do it yourself (DIY) community there has been a widespread interest for users to manufacture their own feedstock filament leading to a large growth in home-use extrusion systems. The low cost of these desktop-grade systems has also made them attractive to academics, but there has not been a widespread effort into determining the efficacy of these small scale extrusion systems as compared to industrial quality extruders which are typically used to manufacture feedstock for FDM platforms. The aim of this study was to compare two extrusion processes: 1) a desktop grade single-screw extruder; and 2) an industrial scale twin-screw extruder. In order to understand differences between their performance and quality of mixing, a rubberized blend of acrylonitrile butadiene styrene (ABS) mixed with styrene ethylene butylene styrene with a maleic anhydride graft (SEBS-g-MA) at different ratios was compounded on each extrusion system. Melt flow index, and mechanical properties were compared. In addition, a raster pattern sensitivity study was performed to evaluate the effect of the extruder system on 3D printed objects. Finally, scanning electron microscopy (SEM) was used to examine the fracture surfaces of spent tensile specimens.

Extent and mechanism of phase separation during the extrusion of calcium phosphate pastes.

PubMed

O'Neill, Rory; McCarthy, Helen O; Cunningham, Eoin; Montufar, Edgar; Ginebra, Maria-Pau; Wilson, D Ian; Lennon, Alex; Dunne, Nicholas

2016-02-01

The aim of this study was to increase understanding of the mechanism and dominant drivers influencing phase separation during ram extrusion of calcium phosphate (CaP) paste for orthopaedic applications. The liquid content of extrudate was determined, and the flow of liquid and powder phases within the syringe barrel during extrusion were observed, subject to various extrusion parameters. Increasing the initial liquid-to-powder mass ratio, LPR, (0.4-0.45), plunger rate (5-20 mm/min), and tapering the barrel exit (45°-90°) significantly reduced the extent of phase separation. Phase separation values ranged from (6.22 ± 0.69 to 18.94 ± 0.69 %). However altering needle geometry had no significant effect on phase separation. From powder tracing and liquid content determination, static zones of powder and a non-uniform liquid distribution was observed within the barrel. Measurements of extrudate and paste LPR within the barrel indicated that extrudate LPR remained constant during extrusion, while LPR of paste within the barrel decreased steadily. These observations indicate the mechanism of phase separation was located within the syringe barrel. Therefore phase separation can be attributed to either; (1) the liquid being forced downstream by an increase in pore pressure as a result of powder consolidation due to the pressure exerted by the plunger or (2) the liquid being drawn from paste within the barrel, due to suction, driven by dilation of the solids matrix at the barrel exit. Differentiating between these two mechanisms is difficult; however results obtained suggest that suction is the dominant phase separation mechanism occurring during extrusion of CaP paste.

Understanding temperature tuning of the all polymer co-extruded laser

NASA Astrophysics Data System (ADS)

Crescimanno, Michael; Andrews, Jim; Aviles, Michael; Dawson, Nathan; Petrus, Joshua; Mazzocco, Anthony; Singer, Ken; Baer, Eric; Song, Hyunmin

2012-10-01

We investigate the effects of elevated temperatures on a few types of all-polymer multilayer films that were fabricated using a co-extrusion melt-process technique. We report on the anisotropic thermal expansion of the multilayer films, which affects the photonic crystal structure via constituent wise induced anisotropic strains and a change in the relative refractive indices. In addition to the characterization of these films in the temperature range of approximately 20-95 degrees C, we show the application to non-contact temperature sensing and wavelength tuning of all polymer Distributed FeedBack (DFB) lasers and Distributed Bragg Reflector (DBR) lasers.

Formation of macromolecules in wheat gluten/starch mixtures during twin-screw extrusion: effect of different additives.

PubMed

Wang, Kaiqiang; Li, Cheng; Wang, Bingzhi; Yang, Wen; Luo, Shuizhong; Zhao, Yanyan; Jiang, Shaotong; Mu, Dongdong; Zheng, Zhi

2017-12-01

Wheat gluten comprises a good quality and inexpensive vegetable protein with an ideal amino acid composition. To expand the potential application of wheat gluten in the food industry, the effect of different additives on the physicochemical and structural properties of wheat gluten/starch mixtures during twin-screw extrusion was investigated. Macromolecules were observed to form in wheat gluten/starch mixtures during twin-screw extrusion, which may be attributed to the formation of new disulfide bonds and non-covalent interactions, as well as Maillard reaction products. Additionally, the water retention capacity and in vitro protein digestibility of all extruded wheat gluten/starch products significantly increased, whereas the nitrogen solubility index and free sulfhydryl group (SH) content decreased, during twin-screw extrusion. Secondary structural analysis showed that α-helices disappeared with the concomitant increase of antiparallel β-sheets, demonstrating the occurrence of protein aggregation. Microstructures suggested that the irregular wheat gluten granular structure was disrupted, with additive addition favoring transformation into a more layered or fibrous structure during twin-screw extrusion. The findings of the present study demonstrate that extrusion might affect the texture and quality of extruded wheat gluten-based foods and suggest that this process might serve as a basis for the high-value application of wheat gluten products. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Poly(ether ester) Ionomers as Water-Soluble Polymers for Material Extrusion Additive Manufacturing Processes.

PubMed

Pekkanen, Allison M; Zawaski, Callie; Stevenson, André T; Dickerman, Ross; Whittington, Abby R; Williams, Christopher B; Long, Timothy E

2017-04-12

Water-soluble polymers as sacrificial supports for additive manufacturing (AM) facilitate complex features in printed objects. Few water-soluble polymers beyond poly(vinyl alcohol) enable material extrusion AM. In this work, charged poly(ether ester)s with tailored rheological and mechanical properties serve as novel materials for extrusion-based AM at low temperatures. Melt transesterification of poly(ethylene glycol) (PEG, 8k) and dimethyl 5-sulfoisophthalate afforded poly(ether ester)s of sufficient molecular weight to impart mechanical integrity. Quantitative ion exchange provided a library of poly(ether ester)s with varying counterions, including both monovalent and divalent cations. Dynamic mechanical and tensile analysis revealed an insignificant difference in mechanical properties for these polymers below the melting temperature, suggesting an insignificant change in final part properties. Rheological analysis, however, revealed the advantageous effect of divalent countercations (Ca 2+ , Mg 2+ , and Zn 2+ ) in the melt state and exhibited an increase in viscosity of two orders of magnitude. Furthermore, time-temperature superposition identified an elevation in modulus, melt viscosity, and flow activation energy, suggesting intramolecular interactions between polymer chains and a higher apparent molecular weight. In particular, extrusion of poly(PEG 8k -co-CaSIP) revealed vast opportunities for extrusion AM of well-defined parts. The unique melt rheological properties highlighted these poly(ether ester) ionomers as ideal candidates for low-temperature material extrusion additive manufacturing of water-soluble parts.

Effect of extrusion rate on morphology of Kaolin/PolyEtherSulfone (PESf) membrane precursor

NASA Astrophysics Data System (ADS)

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.

Modeling of heat transfer in compacted machining chips during friction consolidation process

NASA Astrophysics Data System (ADS)

Abbas, Naseer; Deng, Xiaomin; Li, Xiao; Reynolds, Anthony

2018-04-01

The current study aims to provide an understanding of the heat transfer process in compacted aluminum alloy AA6061 machining chips during the friction consolidation process (FCP) through experimental investigations and mathematical modelling and numerical simulation. Compaction and friction consolidation of machining chips is the first stage of the Friction Extrusion Process (FEP), which is a novel method for recycling machining chips to produce useful products such as wires. In this study, compacted machining chips are modelled as a continuum whose material properties vary with density during friction consolidation. Based on density and temperature dependent thermal properties, the temperature field in the chip material and process chamber caused by frictional heating during the friction consolidation process is predicted. The predicted temperature field is found to compare well with temperature measurements at select points where such measurements can be made using thermocouples.

Evaluation of Enterococcus faecium NRRL B-2354 as a Surrogate for Salmonella During Extrusion of Low-Moisture Food.

PubMed

Verma, Tushar; Wei, Xinyao; Lau, Soon Kiat; Bianchini, Andreia; Eskridge, Kent M; Subbiah, Jeyamkondan

2018-04-01

Salmonella in low-moisture foods is an emerging challenge due to numerous food product recalls and foodborne illness outbreaks. Identification of suitable surrogate is critical for process validation at industry level due to implementation of new Food Safety Modernization Act of 2011. The objective of this study was to evaluate Enterococcus faecium NRRL B-2354 as a surrogate for Salmonella during the extrusion of low-moisture food. Oat flour, a low-moisture food, was adjusted to different moisture (14% to 26% wet basis) and fat (5% to 15% w/w) contents and was inoculated with E. faecium NRRL B-2354. Inoculated material was then extruded in a lab-scale single-screw extruder running at different screw speeds (75 to 225 rpm) and different temperatures (75, 85, and 95 °C). A split-plot central composite 2nd order response surface design was used, with the central point replicated six times. The data from the selective media (m-Enterococcus agar) was used to build the response surface model for inactivation of E. faecium NRRL B-2354. Results indicated that E. faecium NRRL B-2354 always had higher heat resistance compared to Salmonella at all conditions evaluated in this study. However, the patterns of contour plots showing the effect of various product and process parameters on inactivation of E. faecium NRRL B-2354 was different from that of Salmonella. Although E. faecium NRRL B-2354 may be an acceptable surrogate for extrusion of low-moisture products due to higher resistance than Salmonella, another surrogate with similar inactivation behavior may be preferred and needs to be identified. Food Safety Modernization Act requires the food industry to validate processing interventions. This study validated extrusion processing and demonstrated that E. faecium NRRL B-2354 is an acceptable surrogate for extrusion of low-moisture products. The developed response surface model allows the industry to identify process conditions to achieve a desired lethality for their products based on composition. © 2018 Institute of Food Technologists®.

Himalayan tectonics explained by extrusion of a low-viscosity crustal channel coupled to focused surface denudation.

PubMed

Beaumont, C; Jamieson, R A; Nguyen, M H; Lee, B

2001-12-13

Recent interpretations of Himalayan-Tibetan tectonics have proposed that channel flow in the middle to lower crust can explain outward growth of the Tibetan plateau, and that ductile extrusion of high-grade metamorphic rocks between coeval normal- and thrust-sense shear zones can explain exhumation of the Greater Himalayan sequence. Here we use coupled thermal-mechanical numerical models to show that these two processes-channel flow and ductile extrusion-may be dynamically linked through the effects of surface denudation focused at the edge of a plateau that is underlain by low-viscosity material. Our models provide an internally self-consistent explanation for many observed features of the Himalayan-Tibetan system.

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

PubMed

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

2017-11-01

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.

Development of thermoplastic starch blown film by incorporating plasticized chitosan.

PubMed

Dang, Khanh Minh; Yoksan, Rangrong

2015-01-22

The objective of the present work was to improve blown film extrusion processability and properties of thermoplastic starch (TPS) film by incorporating plasticized chitosan, with a content of 0.37-1.45%. The effects of chitosan on extrusion processability and melt flow ability of TPS, as well as that on appearance, optical properties, thermal properties, viscoelastic properties and tensile properties of the films were investigated. The possible interactions between chitosan and starch molecules were evaluated by FTIR and XRD techniques. Chitosan and starch molecules could interact via hydrogen bonds, as confirmed from the blue shift of OH bands and the reduction of V-type crystal formation. Although the incorporation of chitosan caused decreased extensibility and melt flow ability, as well as increased yellowness and opacity, the films possessed better extrusion processability, increased tensile strength, rigidity, thermal stability and UV absorption, as well as reduced water absorption and surface stickiness. The obtained TPS/chitosan-based films offer real potential application in the food industry, e.g. as edible films. Copyright © 2014 Elsevier Ltd. All rights reserved.

Modelling and optimisation of enzymatic extrusion pretreatment of broken rice for rice wine manufacture.

PubMed

Li, Hongyan; Wei, Benxi; Wu, Chunsen; Zhang, Bao; Xu, Xueming; Jin, Zhengyu; Tian, Yaoqi

2014-05-01

The manufacture of Chinese rice wine involves an uneconomical, time-consuming, and environmentally unfriendly pretreatment process. In this study, the enzymatic extrusion of broken rice was applied to the brewing of rice wine. The response surface methodology was used to study the effects of the barrel temperature (BT), moisture content (MC), and amylase concentration (AC) on the alcohol yield. A second-order polynomial model had a good fit to the experimental data and the coefficient of determination (R(2)) was 0.9879. According to the model, the optimal parameters required to obtain the highest alcoholic degree of 17.94% were: BT=100.14°C, MC=43%, and AC=1.45‰. Under these optimal conditions, the alcoholic degree actually reached 18.3%, which was close to the value predicted by the model. Enzymatic extrusion improved the yeast growth and alcohol yield during the fermentation process. The fermentation recovery and efficiency of processed rice wine were 38.07% and 94.66%, respectively. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Hot-melt extrusion of sugar-starch-pellets.

PubMed

Yeung, Chi-Wah; Rein, Hubert

2015-09-30

Sugar-starch-pellets (syn. sugar spheres) are usually manufactured through fluidized bed granulation or wet extrusion techniques. This paper introduces hot-melt extrusion (HME) as an alternative method to manufacture sugar-starch-pellets. A twin-screw extruder coupled with a Leistritz Micro Pelletizer (LMP) cutting machine was utilized for the extrusion of different types (normal-, waxy-, and high-amlyose) of corn starch, blended with varying amounts of sucrose. Pellets were characterized for their physicochemical properties including crystallinity, particle size distribution, tensile strength, and swelling expansion. Furthermore, the influence of sugar content and humidity on the product was investigated. Both sucrose and water lowered the Tg of the starch system allowing a convenient extrusion process. Mechanical strength and swelling behavior could be associated with varying amylose and amylopectin. X-ray powder diffractometric (XRPD) peaks of increasing sucrose contents appeared above 30%. This signified the oversaturation of the extruded starch matrix system with sucrose. Otherwise, had the dissolved sucrose been embedded into the molten starch matrix, no crystalline peak could have been recognized. The replacement of starch with sucrose reduced the starch pellets' swelling effect, which resulted in less sectional expansion (SEI) and changed the surface appearance. Further, a nearly equal tensile strength could be detected for sugar spheres with more than 40% sucrose. This observation stands in good relation with the analyzed values of the commercial pellets. Both techniques (fluidized bed and HME) allowed a high yield of spherical pellets (less friability) for further layering processes. Thermal influence on the sugar-starch system is still an obstacle to be controlled. Copyright © 2015 Elsevier B.V. All rights reserved.

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

PubMed

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. © 2016 Institute of Food Technologists®

Impact of Thermomechanical Fiber Pre-Treatment Using Twin-Screw Extrusion on the Production and Properties of Renewable Binderless Coriander Fiberboards.

PubMed

Uitterhaegen, Evelien; Labonne, Laurent; Merah, Othmane; Talou, Thierry; Ballas, Stéphane; Véronèse, Thierry; Evon, Philippe

2017-07-17

The aim of this study consisted of manufacturing renewable binderless fiberboards from coriander straw and a deoiled coriander press cake, thus at the same time ensuring the valorization of crop residues and process by-products. The press cake acted as a natural binder inside the boards owing to the thermoplastic behavior of its protein fraction during thermopressing. The influence of different fiber-refining methods was evaluated and it was shown that a twin-screw extrusion treatment effectively improved fiber morphology and resulted in fiberboards with enhanced performance as compared to a conventional grinding process. The best fiberboard was produced with extrusion-refined straw using a 0.4 liquid/solid (L/S) ratio and with 40% press cake addition. The water sensitivity of the boards was effectively reduced by 63% through the addition of an extrusion raw material premixing operation and thermal treatment of the panels at 200 °C, resulting in materials with good performance showing a flexural strength of 29 MPa and a thickness swelling of 24%. Produced without the use of any chemical adhesives, these fiberboards could thus present viable, sustainable alternatives for current commercial wood-based materials such as oriented strand board, particleboard and medium-density fiberboard, with high cost-effectiveness.

Formulation development and process analysis of drug-loaded filaments manufactured via hot-melt extrusion for 3D-printing of medicines.

PubMed

Korte, Carolin; Quodbach, Julian

2018-02-09

Three dimensional(3D)-printing via fused deposition modeling (FDM) allows the production of individualized solid dosage forms. However, for bringing this benefit to the patient, active pharmaceutical ingredient (API)-loaded filaments of pharmaceutical grade excipients are necessary as feedstock and have to be produced industrially. As large-scale production of API-loaded filaments has not been described in literature, this study presents a development of 3D-printable filaments, which can continuously be produced via hot-melt extrusion. Further, a combination of testing methods for mechanical resilience of filaments was applied to improve the prediction of their printability. Eudragit RL was chosen as a sustained release polymer and theophylline (30%) as thermally stable model drug. Stearic acid (7%) and polyethylene glycol 4000 (10%), were evaluated as suitable plasticizers for producing 3D-printable filaments. The two formulations were printed into solid dosage forms and analyzed regarding their dissolution profiles. This revealed that stearic acid maintained sustained release properties of the matrix whereas polyethylene glycol 4000 did not. Analysis of the continuous extrusion process was done using a design of experiments. It showed that powder feed rate and speed of the stretching device used after extrusion predominantly determine the diameter of the filament and thereby the mechanical resilience of a filament.

Impact of Thermomechanical Fiber Pre-Treatment Using Twin-Screw Extrusion on the Production and Properties of Renewable Binderless Coriander Fiberboards

PubMed Central

Uitterhaegen, Evelien; Labonne, Laurent; Merah, Othmane; Talou, Thierry; Ballas, Stéphane; Véronèse, Thierry

2017-01-01

The aim of this study consisted of manufacturing renewable binderless fiberboards from coriander straw and a deoiled coriander press cake, thus at the same time ensuring the valorization of crop residues and process by-products. The press cake acted as a natural binder inside the boards owing to the thermoplastic behavior of its protein fraction during thermopressing. The influence of different fiber-refining methods was evaluated and it was shown that a twin-screw extrusion treatment effectively improved fiber morphology and resulted in fiberboards with enhanced performance as compared to a conventional grinding process. The best fiberboard was produced with extrusion-refined straw using a 0.4 liquid/solid (L/S) ratio and with 40% press cake addition. The water sensitivity of the boards was effectively reduced by 63% through the addition of an extrusion raw material premixing operation and thermal treatment of the panels at 200 °C, resulting in materials with good performance showing a flexural strength of 29 MPa and a thickness swelling of 24%. Produced without the use of any chemical adhesives, these fiberboards could thus present viable, sustainable alternatives for current commercial wood-based materials such as oriented strand board, particleboard and medium-density fiberboard, with high cost-effectiveness. PMID:28714928

Effects of extrusion, infrared and microwave processing on Maillard reaction products and phenolic compounds in soybean.

PubMed

Zilić, Slađana; Mogol, Burçe Ataç; Akıllıoğlu, Gül; Serpen, Arda; Delić, Nenad; Gökmen, Vural

2014-01-15

The Maillard reaction indicators furosine, hydroxymethylfurfural (HMF), acrylamide and color were determined to evaluate heat effects induced during extrusion, infrared and microwave heating of soybean. In addition, the present paper aimed to study changes in the phenolic compounds, as well as in the overall antioxidant properties of different soybean products in relation to heating at 45-140 °C during the processes. Soybean proteins were highly sensible to Maillard reaction and furosine was rapidly formed under slight heating conditions during extrusion and infrared heating. Microwave heating at lower temperatures for a longer time yielded lower acrylamide levels in the final soybean products, as a result of its partial degradation. However, during infrared heating, acrylamide formation greatly increased with decreasing moisture content. After a short time of extrusion and infrared heating at 140 °C and microwave heating at 135 °C for 5 min, concentrations of HMF increased to 11.34, 26.21 and 34.97 µg g(-1), respectively. The heating conditions caused formation of acrylamide, HMF and furosine in high concentration. The results indicate that the complex structure of soybeans provides protection of phenolic compounds from thermal degradation, and that Maillard reaction products improved the antioxidant properties of heat-treated soybean. © 2013 Society of Chemical Industry.

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

NASA Astrophysics Data System (ADS)

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

2017-08-01

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 subduction and coeval lateral extrusion of the upper plate are compatible processes leading to similar deformation structures within the extruding region as compared to the classical setup, lithosphere-scale indentation. Strong coupling across the subduction boundary allows for the transfer of stresses to the upper plate, where strain regimes are characterized by crustal thickening near a confined margin and dominated by lateral displacement of material near a weak lateral confinement. The strain regimes propagate laterally during ongoing convergence creating an area of overlap characterized by transpression. When subduction is oblique to the convergence direction, the upper plate is less deformed and as a consequence the amount of lateral extrusion decreases. In addition, strain is partitioned along the oblique plate boundary resulting in less subduction in expense of right lateral displacement close to the weak lateral confinement. Both oblique and orthogonal subduction models have a strong resemblance to lateral extrusion tectonics of the Eastern Alps (Europe), where subduction of the adjacent Adriatic plate beneath the Eastern Alps is debated. Our results imply that subduction of Adria is a valid mechanisms to induce extrusion-type deformation within the Eastern Alps lithosphere. Furthermore, our findings suggest that the Oligocene to Late Miocene structural evolution of the Eastern Alps reflects a phase of oblique subduction followed by a later stage of orthogonal subduction conform a Miocene shift in the plate motion of Adria. Oblique subduction also provides a viable mechanism to explain the rapid decrease in slab length of the Adriatic plate beneath the Eastern Alps towards the Pannonian Basin.

Efficacy of Synaptic Inhibition Depends on Multiple, Dynamically Interacting Mechanisms Implicated in Chloride Homeostasis

PubMed Central

Doyon, Nicolas; Prescott, Steven A.; Castonguay, Annie; Godin, Antoine G.; Kröger, Helmut; De Koninck, Yves

2011-01-01

Chloride homeostasis is a critical determinant of the strength and robustness of inhibition mediated by GABAA receptors (GABAARs). The impact of changes in steady state Cl− gradient is relatively straightforward to understand, but how dynamic interplay between Cl− influx, diffusion, extrusion and interaction with other ion species affects synaptic signaling remains uncertain. Here we used electrodiffusion modeling to investigate the nonlinear interactions between these processes. Results demonstrate that diffusion is crucial for redistributing intracellular Cl− load on a fast time scale, whereas Cl−extrusion controls steady state levels. Interaction between diffusion and extrusion can result in a somato-dendritic Cl− gradient even when KCC2 is distributed uniformly across the cell. Reducing KCC2 activity led to decreased efficacy of GABAAR-mediated inhibition, but increasing GABAAR input failed to fully compensate for this form of disinhibition because of activity-dependent accumulation of Cl−. Furthermore, if spiking persisted despite the presence of GABAAR input, Cl− accumulation became accelerated because of the large Cl− driving force that occurs during spikes. The resulting positive feedback loop caused catastrophic failure of inhibition. Simulations also revealed other feedback loops, such as competition between Cl− and pH regulation. Several model predictions were tested and confirmed by [Cl−]i imaging experiments. Our study has thus uncovered how Cl− regulation depends on a multiplicity of dynamically interacting mechanisms. Furthermore, the model revealed that enhancing KCC2 activity beyond normal levels did not negatively impact firing frequency or cause overt extracellular K− accumulation, demonstrating that enhancing KCC2 activity is a valid strategy for therapeutic intervention. PMID:21931544

The Energetics and Physiological Impact of Cohesin Extrusion.

PubMed

Vian, Laura; Pękowska, Aleksandra; Rao, Suhas S P; Kieffer-Kwon, Kyong-Rim; Jung, Seolkyoung; Baranello, Laura; Huang, Su-Chen; El Khattabi, Laila; Dose, Marei; Pruett, Nathanael; Sanborn, Adrian L; Canela, Andres; Maman, Yaakov; Oksanen, Anna; Resch, Wolfgang; Li, Xingwang; Lee, Byoungkoo; Kovalchuk, Alexander L; Tang, Zhonghui; Nelson, Steevenson; Di Pierro, Michele; Cheng, Ryan R; Machol, Ido; St Hilaire, Brian Glenn; Durand, Neva C; Shamim, Muhammad S; Stamenova, Elena K; Onuchic, José N; Ruan, Yijun; Nussenzweig, Andre; Levens, David; Aiden, Erez Lieberman; Casellas, Rafael

2018-05-17

Cohesin extrusion is thought to play a central role in establishing the architecture of mammalian genomes. However, extrusion has not been visualized in vivo, and thus, its functional impact and energetics are unknown. Using ultra-deep Hi-C, we show that loop domains form by a process that requires cohesin ATPases. Once formed, however, loops and compartments are maintained for hours without energy input. Strikingly, without ATP, we observe the emergence of hundreds of CTCF-independent loops that link regulatory DNA. We also identify architectural "stripes," where a loop anchor interacts with entire domains at high frequency. Stripes often tether super-enhancers to cognate promoters, and in B cells, they facilitate Igh transcription and recombination. Stripe anchors represent major hotspots for topoisomerase-mediated lesions, which promote chromosomal translocations and cancer. In plasmacytomas, stripes can deregulate Igh-translocated oncogenes. We propose that higher organisms have coopted cohesin extrusion to enhance transcription and recombination, with implications for tumor development. Copyright © 2018 Elsevier Inc. All rights reserved.

The effect of feed moisture and temperature on tannin content, antioxidant and antimicrobial activities of extruded chestnuts.

PubMed

Obiang-Obounou, Brice Wilfried; Ryu, Gi Hyung

2013-12-15

This study focuses on the effect of extrusion processing on tannin reduction, phenolic content, flavonoid content, antioxidant and anitimicrobial activity. Extrusion temperature (120 and 140 °C) and feed moisture (25% and 28%) were used on the tannin content, antioxidant and antimicrobial activities. Extrusion cooking reduced tannin content up to 78%, and improved antioxidant activity from 12.89% to 21.17% in a concentration dependant manner without affecting its antimicrobial activity that varied from 250 to 500 mg. The time-kill assay confirmed the ability of extruded chestnut to reduce Pseudomonas aeruginosa count below detectable limit that reduced the original inoculum by 3log10 CFU/mL. Overall, the results showed that extrusion cooking might serve as a tool for tannin reduction and could improve the antioxidant and antimicrobial properties of chestnut, which might be helpful for chestnut related products in the food industry. Copyright © 2013 Elsevier Ltd. All rights reserved.

Analysis and Prediction of the Billet Butt and Transverse Weld in the Continuous Extrusion Process of a Hollow Aluminum Profile

NASA Astrophysics Data System (ADS)

Lou, Shumei; Wang, Yongxiao; Liu, Chuanxi; Lu, Shuai; Liu, Sujun; Su, Chunjian

2017-08-01

In continuous extrusions of aluminum profiles, the thickness of the billet butt and the length of the discarded extrudate containing the transverse weld play key roles in reducing material loss and improving product quality. The formation and final distribution of the billet butt and transverse weld depend entirely on the flow behavior of the billet skin material. This study examined the flow behavior of the billet skin material as well as the formation and evolution of the billet butt and the transverse weld in detail through numerical simulation and a series of experiments. In practical extrusions, even if the billet skin is removed by lathe turning shortly before extrusion, billet skin impurities are still distributed around the transverse weld and in the billet butt. The thickness of the scrap billet butt and the length of the discarded extrudate containing the transverse weld can be exactly predicted via simulation.

Proving the viability of manufacturing of multi-layer steel/vanadium alloy/steel composite tubes by numerical simulations and experiment

NASA Astrophysics Data System (ADS)

Nechaykina, T.; Nikulin, S.; Rozhnov, A.; Molotnikov, A.; Zavodchikov, S.; Estrin, Y.

2018-05-01

Vanadium alloys are promising structural materials for fuel cladding tubes for fast-neutron reactors. However, high solubility of oxygen and nitrogen in vanadium alloys at operating temperatures of 700 °C limits their application. In this work, we present a novel composite structure consisting of vanadium alloy V-4Ti-4Cr (provides high long-term strength of the material) and stainless steel Fe-0.2C-13Cr (as a corrosion resistant protective layer). It is produced by co-extrusion of these materials forming a three-layered tube. Finite element simulations were utilised to explore the influence of the various co-extrusion parameters on manufacturability of multi-layered tubes. Experimental verification of the numerical modelling was performed using co-extrusion with the process parameters suggested by the numerical simulations. Scanning electron microscopy and microhardness measurements revealed a defect-free diffusion layer at the interfaces between both materials indicating a good quality bonding for these co-extrusion conditions.

Corrosion anisotropy of titanium deformed by the hydrostatic extrusion

NASA Astrophysics Data System (ADS)

Chojnacka, A.; Kawalko, J.; Koscielny, H.; Guspiel, J.; Drewienkiewicz, A.; Bieda, M.; Pachla, W.; Kulczyk, M.; Sztwiertnia, K.; Beltowska-Lehman, E.

2017-12-01

The corrosion behaviour of titanium rods deformed by hydrostatic extrusion (HE) in artificial saliva (Carter-Brugirard's solution of pH 7.6) was investigated using open-circuit potentials (OCPs), (DC) potentiodynamic polarisation curves and (AC) electrochemical impedance spectroscopy (EIS) techniques. Various electrochemical parameters (corrosion potential Ecorr, corrosion current (icorr), polarisation resistance Rp, charge transfer resistance Rct and oxide film resistance Rf) were analysed. Significant coherence was observed between results achieved from these procedures, i.e., all applied techniques showed the same trend for corrosion resistance. The obtained electrochemical data were then related to the microstructure parameters (crystallographic texture, grain size, grain boundary distribution and density) determined using the EBSD/SEM technique. It was found that the corrosion behaviour of titanium processed by the HE method was superior compared to the unprocessed Ti, and this was clearly dependent on the extrusion direction. The highest corrosion resistance was revealed for the HE-deformed Ti rod of the surface oriented longitudinal (parallel) to the extrusion direction.

Effects of pelleting, extrusion, or extrusion and pelleting on energy and nutrient digestibility in diets containing different levels of fiber and fed to growing pigs.

PubMed

Rojas, O J; Vinyeta, E; Stein, H H

2016-05-01

An experiment was conducted to determine effects of pelleting, extrusion, and extrusion and pelleting on energy and nutrient digestibility in diets containing low, medium, or high concentrations of fiber. Three diets were formulated: 1) the low-fiber diet contained corn and soybean meal; 2) the medium-fiber diet contained corn, soybean meal, and 25% distillers dried grains with solubles (DDGS); and 3) the high-fiber diet contained corn, soybean meal, 25% DDGS, and 20% soybean hulls. Each diet was divided into 4 batches after mixing. One batch was not further processed and was fed in a meal form, one batch was pelleted at 85°C, one batch was extruded at 115°C using a single-screw extruder, and one batch was extruded at 115°C and then pelleted at 85°C. Thus, 12 different diets were produced. Twenty-four growing pigs (26.5 ± 1.5 kg initial BW) had a T-cannula installed in the distal ileum and were allotted to the 12 diets in a split-plot design with 8 pigs allotted to the low-fiber diets, the medium-fiber diets, and the high-fiber diets, respectively. Diets were fed to the pigs during four 14-d periods. Within each type of diet, the 8 pigs were fed the diets produced using the 4 processing technologies. Therefore, there were 8 replicate pigs per diet. Pigs were adjusted to their diets for 14 d before the experiment was initiated. Each of the four 14-d periods consisted of 5 d for adaptation, 5 d of fecal collection according to the marker to marker approach, and ileal digesta were collected on d 13 and 14. Results indicated that pelleting, extrusion, or extrusion and pelleting improved ( < 0.05) the apparent ileal digestibility of starch and most indispensable AA. In most cases, there were no differences between the pelleted, the extruded, and the extruded and pelleted diets. The apparent total tract digestibility of GE was also improved ( < 0.05) by pelleting and by the combination of extrusion and pelleting. The ME of pelleted diets was greater ( < 0.05) than that of meal diets for the low- and medium-fiber diets, but this was not the case for high-fiber diets (interaction, < 0.05). Medium- and high-fiber diets that were extruded had greater ME ( < 0.05) than meal diets, but that was not the case for low-fiber diets. These data indicate that energy utilization may be improved by pelleting or extrusion or by a combination of the 2 technologies, but the response seems to be greater for extrusion in diets that are relatively high in fiber.

Pancreatic cell immobilization in alginate beads produced by emulsion and internal gelation.

PubMed

Hoesli, Corinne A; Raghuram, Kamini; Kiang, Roger L J; Mocinecová, Dušana; Hu, Xiaoke; Johnson, James D; Lacík, Igor; Kieffer, Timothy J; Piret, James M

2011-02-01

Alginate has been used to protect transplanted pancreatic islets from immune rejection and as a matrix to increase the insulin content of islet progenitor cells. The throughput of alginate bead generation by the standard extrusion and external gelation method is limited by the rate of droplet formation from nozzles. Alginate bead generation by emulsion and internal gelation is a scaleable alternative that has been used with biological molecules and microbial cells, but not mammalian cells. We describe the novel adaptation of this process to mammalian cell immobilization. After optimization, the emulsion process yielded 90 ± 2% mouse insulinoma 6 (MIN6) cell survival, similar to the extrusion process. The MIN6 cells expanded at the same rate in both bead types to form pseudo-islets with increased glucose stimulation index compared to cells in suspension. The emulsion process was suitable for primary pancreatic exocrine cell immobilization, leading to 67 ± 32 fold increased insulin expression after 10 days of immobilized culture. Due to the scaleability and broad availability of stirred mixers, the emulsion process represents an attractive option for laboratories that are not equipped with extrusion-based cell encapsulators, as well as for the production of immobilized or encapsulated cellular therapeutics on a clinical scale. © 2010 Wiley Periodicals, Inc.

Microstructures and mechanical behavior of magnesium processed by ECAP at ice-water temperature

NASA Astrophysics Data System (ADS)

Zuo, Dai; Li, Taotao; Liang, Wei; Wen, Xiyu; Yang, Fuqian

2018-05-01

Magnesium of high purity is processed by equal channel angular pressing (ECAP) up to eight passes at the ice-water temperature, in which a core–shell-like structure is used. The core–shell-like structure consists of pure iron (Fe) of 1.5 mm in thickness as the shell and magnesium (Mg) as the core. The microstructure, texture and mechanical behavior of the ECAP-processed Mg are studied. The ECAP processing leads to the formation of fine and equiaxed grains of ~1.1 µm. The basal planes initially parallel to the extrusion direction evolve to slanted basal planes with the tilting angle in a range of 25°–45° to the extrusion direction. Increasing the number of the extrusion passes leads to the decreasing of twins and dislocation density in grains, while individual grains after eight passes still have high dislocation density. The large decreases of twins and the dislocation density make dynamic recrystallization (DRX) difficult, resulting in the decrease of the degree of DRX. Tension test reveals that the mechanical behavior of the ECAP-processed Mg is dependent on grain refinement and textures. The yield strength of the ECAP-extruded Mg first increases with the decrease of the grain size, and then decreases with further decrease of the grain size.

Effect of feed moisture, extrusion temperature and screw speed on properties of soy white flakes based aquafeed: a response surface analysis.

PubMed

Singh, Sushil K; Muthukumarappan, Kasiviswanathan

2016-04-01

Soy white flakes (SWF) is an intermediate product during soy bean processing. It is an untoasted inexpensive product and contains around 51% of crude protein. It can be a potential source of protein to replace fish meal for developing aquafeed. The extrusion process is versatile and is used for the development of aquafeed. Our objective was to study the effects of inclusion of SWF (up to 50%) and other extrusion processing parameters such as barrel temperature and screw speed on the properties of aquafeed extrudates using a single-screw extruder. Extrudate properties, including pellet durability index, bulk density, water absorption and solubility indices and mass flow rate, were significantly (P < 0.05) affected by the process variables. SWF was the most significant variable with quadratic effects on most of the properties. Increasing temperature and screw speed resulted in increase in durability and mass flow rate of extrudates. Response surface regression models were established to correlate the properties of extrudates to the process variables. SWF was used as an alternative protein source of fish meal. Our study shows that aquafeed with high durability, lower bulk density and lower water absorption and higher solubility indices can be obtained by adding SWF up to 40%. © 2015 Society of Chemical Industry.

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

PubMed

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.

Defeating anisotropy in material extrusion 3D printing via materials development

NASA Astrophysics Data System (ADS)

Torrado Perez, Angel Ramon

Additive Manufacturing technologies has been in continuous development for more than 35 years. Specifically, the later denominated Material Extrusion Additive Manufacturing (MEAM), was first developed by S. Scott Crump around 1988 and trademarked later as Fused Deposition Modeling (FDM). Although all of these technologies have been around for a while, it was not until recently that they have been more accessible to everyone. Today, the market of 3D printers covers all ranges of price, from very specialized, heavy and expensive machines, to desktop printers of only a few cubic inches in volume. Until recently, FDM technology had remained somewhat stagnant in terms of developments; however, with the new market boom, scholars and hobbyists have opened new doors for investigation in this area. The technology is now better understood from a software, mechanical, electrical and not less important, materials point of view. The current availability of materials for MEAM is very broad: PLA (Polylactic Acid), ABS (Acrylonitrile Butadiene Styrene), PC (Polycarbonate), PEEK (Polyether Ether Ketone), nylon, polyurethanes, and many others. Even so, these are all materials that were used before for other technologies, adapted but not specifically developed for MEAM. The processes that take place during the production of a part are currently not very well understood, and the final properties exhibited are long ways away from reaching the potential of more traditional manufacturing techniques. Due to the nature of the process, all the material properties always display a certain level of anisotropy. The research covered in these pages aims to shed some light on understanding the different mechanics taking place during the extrusion process of additive manufacturing. The development of new materials for MEAM has been explored. Several blends and composites have been developed, and their tensile properties and fracture mechanics evaluated. The blending of different combinations of ABS, UHMWPE (Ultra High Molecular Weight Polyethylene) and SEBS (Styrene Ethylene Butylene Styrene) were further examined due to the potential they demonstrated as low anisotropic materials in terms of strength. Also, the geometrical influence of different standard tensile specimens was studied. The development of materials that lead to lowered anisotropy on the strength of 3D printed parts has been successfully demonstrated, and alternative methodologies for the evaluation of anisotropic characteristics has been proposed as well. The present work shows the beginning to a better understanding of the mechanics taking place during the fusion of deposited material in MEAM.

Using Flory-Huggins phase diagrams as a pre-formulation tool for the production of amorphous solid dispersions: a comparison between hot-melt extrusion and spray drying.

PubMed

Tian, Yiwei; Caron, Vincent; Jones, David S; Healy, Anne-Marie; Andrews, Gavin P

2014-02-01

Amorphous drug forms provide a useful method of enhancing the dissolution performance of poorly water-soluble drugs; however, they are inherently unstable. In this article, we have used Flory-Huggins theory to predict drug solubility and miscibility in polymer candidates, and used this information to compare spray drying and melt extrusion as processes to manufacture solid dispersions. Solid dispersions were prepared using two different techniques (hot-melt extrusion and spray drying), and characterised using a combination of thermal (thermogravimetric analysis and differential scanning calorimetry), spectroscopic (Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction methods. Spray drying permitted generation of amorphous solid dispersions across a wider drug concentration than melt extrusion. Melt extrusion provided sufficient energy for more intimate mixing to be achieved between drug and polymer, which may improve physical stability. It was also confirmed that stronger drug-polymer interactions might be generated through melt extrusion. Remixing and dissolution of recrystallised felodipine into the polymeric matrices did occur during the modulated differential scanning calorimetry analysis, but the complementary information provided from FTIR confirms that all freshly prepared spray-dried samples were amorphous with the existence of amorphous drug domains within high drug-loaded samples. Using temperature-composition phase diagrams to probe the relevance of temperature and drug composition in specific polymer candidates facilitates polymer screening for the purpose of formulating solid dispersions. © 2013 Royal Pharmaceutical Society.

The Effects of Cooking Process and Meat Inclusion on Pet Food Flavor and Texture Characteristics

PubMed Central

Koppel, Kadri; Gibson, Michael; Alavi, Sajid; Aldrich, Greg

2014-01-01

Simple Summary The results of this research indicate that processing (baked vs. extruded) plays an important role in determining pet food product texture. In addition, raw ingredients (fresh meat vs. meal-based) did not consistently affect product sensory characteristics. These results may help pet food technologists better understand factors that affect palatability. Abstract The pet food industry is an important portion of the food and feed industries in the US. The objectives of this study were (1) to determine cooking method (baking or extrusion), meat inclusion (0 or 20%), and extrusion thermal to mechanical energy ratios (low, medium, and high) effects on sensory and volatile properties of pet foods, and (2) to determine associations among sensory and volatile characteristics of baked and extruded pet foods. Descriptive sensory analysis and gas chromatography-mass spectrometry were used to analyze the pet food samples. It was found that baked samples were lighter in color (2.0–2.6 baked vs. 3.5–4.3 extruded, color intensity scale 0–15), and had lower levels of attributes that indicated rancidity (i.e., fishy flavor; 0.3–0.6 baked, 0.6–1.5 extruded, scale 0–15), whereas extruded pet foods were more cohesive in mass, more friable, hard, and crisp, but less powdery than baked samples. Fresh meat inclusion tended to decrease bitterness and increase fishy flavor and cohesiveness of pet foods. High thermal to mechanical energy ratio during extrusion resulted in less musty and more porous kibbles. The main volatile compounds included aldehydes, such as hexanal and heptanal, ketones, and alcohols. Extruded samples did not contain methylpyrazine, while baked samples did not contain 2-butyl furan. Future studies should consider evaluating the relationship between sensory results and animal palatability for these types of foods. PMID:26480040

Thermoelectric Properties of Texture-Controlled (GeTe) x (AgSbTe2)100- x ( x = 75, 80, 85, and 90) Alloys Fabricated by Gas-Atomization and Hot-Extrusion Processes

NASA Astrophysics Data System (ADS)

Kim, Hyo-Seob; Dharmaiah, Peyala; Hong, Soon-Jik

2018-06-01

In this study, p-type (GeTe) x (AgSbTe2)100- x : TAGS- x (where x = 75, 80, 85, and 90) thermoelectric materials were fabricated by a combination of gas atomization and a hot-extrusion process, and the effects of chemical composition on microstructure, thermoelectric, and mechanical properties were investigated. The extruded samples exhibited higher relative densities (> 99%), and a significant orientation degree parallel to the extrusion direction with fine and homogeneous microstructure was observed. The hardness of extruded samples was around 200-260 kgf/mm2, which indicates that they have much better mechanical properties than most other TE materials. The power factor of the extruded samples showed excellent values; the maximum power factor achieved was 3.81 × 10-3 W/mK2 for TAGS-90 at 723 K due to an effective combination of the Seebeck coefficient and electrical conductivity.

Changes in the functional properties and antinutritional factors of extruded hard-to-cook common beans (Phaseolus vulgaris, L.).

PubMed

Batista, Karla A; Prudêncio, Sandra H; Fernandes, Kátia F

2010-04-01

The biochemical and functional properties of 2 hard-to-cook common bean cultivars (Phaseolus vulgaris, L.) were investigated after the extrusion process. Beans of BRS pontal and BRS grafite cultivars were milled and extruded at 150 degrees C, with a compression ratio screw of 3 : 1, 5-mm die, and screw speed of 150 rpm. Extrudate flours were evaluated for water solubility (WS), water absorption index (WAI), oil absorption capacity (OAC), foaming capacity (FC), emulsifying activity (EA), antinutritional factors, and in vitro protein and starch digestibility. Results indicated that the extrusion significantly decreased antinutrients such as phytic acid, lectin, alpha-amylase, and trypsin inhibitors, reduced the emulsifying capacity and eliminated the FC in both BRS pontal and BRS grafite cultivars. In addition, the WS, WAI, and in vitro protein and starch digestibility were improved by the extrusion process. These results indicate that it is possible to produce new extruded products with good functional and biochemical properties from these common bean cultivars.

Effect of hot and cold severe deformation by extrusion on the properties of lead and aluminum alloys

NASA Astrophysics Data System (ADS)

Ganiev, M. M.; Shibakov, V. G.; Pankratov, D. L.; Shibakov, R. V.

2015-07-01

The study of the effect of severe plastic deformation (SPD) by extrusion shows that the ductility of lead after several cycles of SPD increases significantly (3-4 times) as compared to as-cast samples. An aluminum alloy after this processing is hardened by a factor of 2.3-2.5, with ductility decreasing by 2.5-2.7 times, as compared to the as-delivered state.

Effect of Aluminum Addition on the Evolution of Microstructure, Crystallographic Texture and Mechanical Properties of Single Phase Hexagonal Close Packed Mg-Li Alloys

NASA Astrophysics Data System (ADS)

Bhagat Singh, P.; Sabat, R. K.; Kumaran, S.; Suwas, S.

2018-02-01

In the present investigation, an effort has been made to understand the effect of aluminum addition to α Mg-Li alloys. The corresponding composition Mg-4Li- xAl ( x = 0, 2, 4 and 6 wt.%) alloys have been prepared by stir casting route under an argon environment. Extrusion was carried out at 300 °C with the extrusion ratio of 15:1. Significant grain refinement was observed after extrusion. X-ray diffraction-based investigation of the cast and extruded alloys showed the presence of intermetallic compounds such as Mg17Al12 and AlLi in the Al-rich alloys namely, Mg-4Li- xAl ( x = 4 and 6 wt.%). These precipitates were also present in the extruded plus annealed samples, indicating the stability of the precipitates at high temperature. The bulk x-ray texture measurement revealed a crystallographic texture where the c-axis of the h.c.p crystals was perpendicular to the extrusion direction (ED) for extruded sample. A texture transition was observed on annealing. The c-axis was oriented parallel to the ED. Mechanical properties of the cast, extruded and extruded plus annealed material illustrate that the addition of Al led to enhancement in hardness, yield strength and ultimate tensile strength.

Seismicity associated with quiescent-explosive transitions at dome forming eruptions: The July 2008 Vulcanian Explosion of Soufrière Hills Volcano, Montserrat

NASA Astrophysics Data System (ADS)

Rodgers, Mel; Smith, Patrick; Mather, Tamsin A.; Pyle, David M.

2017-04-01

During long-lived dome-forming eruptions volcanoes often transition between quiescent, effusive, and explosive behaviour. Soufrière Hills Volcano (SHV), Montserrat, has been erupting since 1995 and has repeatedly transitioned between these different phases of activity. At SHV many of the largest explosions have occurred either during periods of dome growth, or as major dome collapse events at the end of extrusion phases. However, on the 29th July 2008 a vulcanian explosion marked the transition from a quiescent phase (Pause 3) to explosion and then extrusion. This was one of the largest explosions by volume and the largest to occur outside a period of lava extrusion. The eruption was preceded by one of the most intense seismic swarms ever recorded at SHV. In this study we analysed precursory seismic data to investigate the subsurface volcanic processes that culminated in this eruption. We used spectral and multiplet analysis techniques, and applied a simple parameterization approach to relate monitoring observations (seismic, SO2, visual) to subsurface interpretations. These techniques would be available to most volcano observatories. Our study suggests that an initial VT swarm, coincident with ash-venting events, can be triggered by ascent of decoupled gas ahead of rising magma. A subsequent large LF swarm shows a coincident decrease in spectral content that we interpret as magma ascent through the upper conduit system. An ash-venting event on 27 July (a few hours before peak event rate) may have triggered rapid microlite growth. We observe an increase in the spectral content of the LF swarm that is concurrent with a decrease in event rates, suggesting pressurization of the magmatic system due to inhibited magmatic outgassing. Our results suggest that pressurization of the magmatic system may have occurred in the final 24 h before the vulcanian explosion. We also observe LP and Hybrid events within the same multiplet, suggesting that these events have very similar source processes and should be considered part of the same classification at SHV. Our study demonstrates the potential for using spectral and multiplet analysis to understand subsurface magmatic processes and for investigating the transition between quiescence and eruption.

A Volume Flux Approach to Cryolava Dome Emplacement on Europa

NASA Technical Reports Server (NTRS)

Quick, Lynnae C.; Fagents, Sarah A.; Hurford, Terry A.; Prockter, Louise M.

2017-01-01

We previously modeled a subset of domes on Europa with morphologies consistent with emplacement by viscous extrusions of cryolava. These models assumed instantaneous emplacement of a fixed volume of fluid onto the surface, followed by relaxation to form domes. However, this approach only allowed for the investigation of late-stage eruptive processes far from the vent and provided little insight into how cryolavas arrived at the surface. Consideration of dome emplacement as cryolavas erupt at the surface is therefore pertinent. A volume flux approach, in which lava erupts from the vent at a constant rate, was successfully applied to the formation of steep-sided volcanic domes on Venus. These domes are believed to have formed in the same manner as candi-date cryolava domes on Europa. In order to gain a more complete understanding of the potential for the emplacement of Europa domes via extrusive volcanism, we have applied this new volume flux approach to the formation of putative cryovolcanic domes on Europa. Assuming as in that europan cryolavas are briny, aqueous solutions which may or may not contain some ice crystal fraction, we present the results of this modeling and explore theories for the formation of low-albedo moats that surround some domes.

Physicochemical Changes and Resistant-Starch Content of Extruded Cornstarch with and without Storage at Refrigerator Temperatures.

PubMed

Neder-Suárez, David; Amaya-Guerra, Carlos A; Quintero-Ramos, Armando; Pérez-Carrillo, Esther; Alanís-Guzmán, María G de J; Báez-González, Juan G; García-Díaz, Carlos L; Núñez-González, María A; Lardizábal-Gutiérrez, Daniel; Jiménez-Castro, Jorge A

2016-08-15

Effects of extrusion cooking and low-temperature storage on the physicochemical changes and resistant starch (RS) content in cornstarch were evaluated. The cornstarch was conditioned at 20%-40% moisture contents and extruded in the range 90-130 °C and at screw speeds in the range 200-360 rpm. The extrudates were stored at 4 °C for 120 h and then at room temperature. The water absorption, solubility index, RS content, viscoelastic, thermal, and microstructural properties of the extrudates were evaluated before and after storage. The extrusion temperature and moisture content significantly affected the physicochemical properties of the extrudates before and after storage. The RS content increased with increasing moisture content and extrusion temperature, and the viscoelastic and thermal properties showed related behaviors. Microscopic analysis showed that extrusion cooking damaged the native starch structure, producing gelatinization and retrogradation and forming RS. The starch containing 35% moisture and extruded at 120 °C and 320 rpm produced the most RS (1.13 g/100 g) after to storage at low temperature. Although the RS formation was low, the results suggest that extrusion cooking could be advantageous for RS production and application in the food industry since it is a pollution less, continuous process requiring only a short residence time.

Innovative Ingredients and Emerging Technologies for Controlling Ice Recrystallization, Texture, and Structure Stability in Frozen Dairy Desserts: A Review.

PubMed

Soukoulis, Christos; Fisk, Ian

2016-11-17

Over the past decade, ice cream manufacturers have developed a strong understanding of the functionality of key ingredients and processing, developing effective explanations for the link between structure forming agents, stability mechanisms, and perceived quality. Increasing demand for products perceived as healthier/more natural with minimal processing has identified a number of new tools to improve quality and storage stability of frozen dairy desserts. Ingredients such as dietary fiber, polysaccharides, prebiotics, alternate sweeteners, fat sources rich in unsaturated fatty acids and ice strucsturing proteins (ISP) have been successfully applied as cryoprotective, texturizing, and structuring agents. Emerging minimal processing technologies including hydrostatic pressure processing, ultrasonic or high pressure assisted freezing, low temperature extrusion and enzymatically induced biopolymers crosslinking have been evaluated for their ability to improve colloidal stability, texture and sensory quality. It is therefore timely for a comprehensive review.

Sodium Hypochlorite Accident: A Systematic Review.

PubMed

Guivarc'h, Maud; Ordioni, Ugo; Ahmed, Hany Mohamed Aly; Cohen, Stephen; Catherine, Jean-Hugues; Bukiet, Frédéric

2017-01-01

Sodium hypochlorite (NaOCl) extrusion beyond the apex, also known as "a hypochlorite accident," is a well-known complication that seldom occurs during root canal therapy. These "accidents" have been the subject of several case reports published over the years. Until now, no publication has addressed the global synthesis of the general and clinical data related to NaOCl extrusion. The main purpose of this article was to conduct a systematic review of previously published case reports to identify, synthesize, and present a critical analysis of the available data. A second purpose was to propose a standardized presentation of reporting data concerning NaOCl extrusions to refine and develop guidelines that should be used in further case report series. A review of clinical cases reporting NaOCl accidents was conducted in June 2016 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist; it combined an electronic search of the PubMed database and an extensive manual search. Forty full-text articles corresponding to 52 case reports published between 1974 and 2015 were selected. Four main categories of data were highlighted: general and clinical information, clinical signs and symptoms of NaOCl extrusions, management of NaOCl extrusions, and healing and prognosis. Overall, up to now, clinical cases were reported in a very unsystematic manner, and some relevant information was missing. A better understanding of the potential causes, management, and prognosis of NaOCl accidents requires a standardization of reported data; this study proposes a template that can fulfill this objective. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Texturized dairy proteins.

PubMed

Onwulata, Charles I; Phillips, John G; Tunick, Michael H; Qi, Phoebi X; Cooke, Peter H

2010-03-01

Dairy proteins are amenable to structural modifications induced by high temperature, shear, and moisture; in particular, whey proteins can change conformation to new unfolded states. The change in protein state is a basis for creating new foods. The dairy products, nonfat dried milk (NDM), whey protein concentrate (WPC), and whey protein isolate (WPI) were modified using a twin-screw extruder at melt temperatures of 50, 75, and 100 degrees C, and moistures ranging from 20 to 70 wt%. Viscoelasticity and solubility measurements showed that extrusion temperature was a more significant (P < 0.05) change factor than moisture content. The degree of texturization, or change in protein state, was characterized by solubility (R(2)= 0.98). The consistency of the extruded dairy protein ranged from rigid (2500 N) to soft (2.7 N). Extruding at or above 75 degrees C resulted in increased peak force for WPC (138 to 2500 N) and WPI (2.7 to 147.1 N). NDM was marginally texturized; the presence of lactose interfered with its texturization. WPI products extruded at 50 degrees C were not texturized; their solubility values ranged from 71.8% to 92.6%. A wide possibility exists for creating new foods with texturized dairy proteins due to the extensive range of states achievable. Dairy proteins can be used to boost the protein content in puffed snacks made from corn meal, but unmodified, they bind water and form doughy pastes with starch. To minimize the water binding property of dairy proteins, WPI, or WPC, or NDM were modified by extrusion processing. Extrusion temperature conditions were adjusted to 50, 75, or 100 degrees C, sufficient to change the structure of the dairy proteins, but not destroy them. Extrusion modified the structures of these dairy proteins for ease of use in starchy foods to boost nutrient levels. Dairy proteins can be used to boost the protein content in puffed snacks made from corn meal, but unmodified, they bind water and form doughy pastes with starch. To minimize the water binding property of dairy proteins, whey protein isolate, whey protein concentrate, or nonfat dried milk were modified by extrusion processing. Extrusion temperature conditions were adjusted to 50, 75, or 100 degrees C, sufficient to change the structure of the dairy proteins, but not destroy them. Extrusion modified the structures of these dairy proteins for ease of use in starchy foods to boost nutrient levels.

Investigation of Thermal and Viscoelastic Properties of Polymers Relevant to Hot Melt Extrusion, IV: Affinisol™ HPMC HME Polymers.

PubMed

Gupta, Simerdeep Singh; Solanki, Nayan; Serajuddin, Abu T M

2016-02-01

Most cellulosic polymers cannot be used as carriers for preparing solid dispersion of drugs by hot melt extrusion (HME) due to their high melt viscosity and thermal degradation at high processing temperatures. Three HME-grade hydroxypropyl methylcelluloses, namely Affinisol™ HPMC HME 15 cP, Affinisol™ HPMC HME 100 cP, and Affinisol™ HPMC HME 4 M, have recently been introduced by The Dow Chemical Co. to enable the preparation of solid dispersion at lower and more acceptable processing temperatures. In the present investigation, physicochemical properties of the new polymers relevant to HME were determined and compared with that of Kollidon(®) VA 64. Powder X-ray diffraction (PXRD), modulated differential scanning calorimetry (mDSC), thermogravimetric analysis (TGA), moisture sorption, rheology, and torque analysis by melt extrusion were applied. PXRD and mDSC showed that the Affinisol™ polymers were amorphous in nature. According to TGA, the onset of degradation for all polymers was >220°C. The Affinisol™ polymers exhibited less hygroscopicity than Kollidon(®) VA 64 and another HPMC polymer, Methocel™ K100LV. The complex viscosity profiles of the Affinisol™ polymers as a function of temperature were similar. The viscosity of the Affinisol™ polymers was highly sensitive to the shear rate applied, and unlike Kollidon(®) VA 64, the viscosity decreased drastically when the angular frequency was increased. Because of the very high shear rate encountered during melt extrusion, Affinisol™ polymers showed capability of being extruded at larger windows of processing temperatures as compared to that of Kollidon(®) VA 64.

Quasi Static and Dynamic Characterization of Equal Channel Angular Extrusion (ECAE) Processed and Rolled AZ31 Magnesium Alloy Sheet

DTIC Science & Technology

2017-04-01

ARL-TR-8006 ● Apr 2017 US Army Research Laboratory Quasi -Static and Dynamic Characterization of Equal Channel Angular Extrusion...originator. ARL-TR-8006 ● Apr 2017 US Army Research Laboratory Quasi -Static and Dynamic Characterization of Equal Channel Angular...April 2017 2. REPORT TYPE Technical Report 3. DATES COVERED (From - To) April 2015–January 2016 4. TITLE AND SUBTITLE Quasi -Static and Dynamic

Hot Melt Extrusion and Spray Drying of Co-amorphous Indomethacin-Arginine With Polymers.

PubMed

Lenz, Elisabeth; Löbmann, Korbinian; Rades, Thomas; Knop, Klaus; Kleinebudde, Peter

2017-01-01

Co-amorphous drug-amino acid systems have gained growing interest as an alternative to common amorphous formulations which contain polymers as stabilizers. Several preparation methods have recently been investigated, including vibrational ball milling on a laboratory scale or spray drying in a larger scale. In this study, the feasibility of hot melt extrusion for continuous manufacturing of co-amorphous drug-amino acid formulations was examined, challenging the fact that amino acids melt with degradation at high temperatures. Furthermore, the need for an addition of a polymer in this process was evaluated. After a polymer screening via the solvent evaporation method, co-amorphous indomethacin-arginine was prepared by a melting-solvent extrusion process without and with copovidone. The obtained products were characterized with respect to their solid-state properties, non-sink dissolution behavior, and stability. Results were compared to those of spray-dried formulations with the same compositions and to spray-dried indomethacin-copovidone. Overall, stable co-amorphous systems could be prepared by extrusion without or with copovidone, which exhibited comparable molecular interaction properties to the respective spray-dried products, while phase separation was detected by differential scanning calorimetry in several cases. The formulations containing indomethacin in combination with arginine and copovidone showed enhanced dissolution behavior over the formulations with only copovidone or arginine. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Bioaccessibility of hydroxycinnamic acids and antioxidant capacity from sorghum bran thermally processed during simulated in vitro gastrointestinal digestion.

PubMed

Salazar-López, Norma Julieta; González-Aguilar, Gustavo A; Rouzaud-Sández, Ofelia; Robles-Sánchez, Maribel

2018-06-01

Sorghum is a source of hydroxycinnamic acids (HCA), which have shown antioxidant, anti-inflammatory and anti-proliferative capacities. However, a high proportion of them have low bioaccessibility due the complex structural disposition of the plant's cell wall. The effects of boiling and extrusion processes on sorghum bran and their effects on the antioxidant capacity and bioaccessibility of HCA during simulated in vitro gastrointestinal digestion were investigated. The bioaccessibility of phenolic compounds was significantly higher in extruded sorghum bran (38.4%) than that obtained by boiling (29.5%). This is consistent with the increase of the antioxidant capacity after in vitro digestion. In contrast, a low bioaccessibility of pure monomeric HCA was observed when they were exposed to in vitro gastrointestinal digestion. There were significant bioaccessibility reductions of 36.8, 19.5, 13.5, 62.1% for caffeic, ρ-coumaric, ferulic and sinapic acids, respectively, when unproccessed sorghum bran was added. Although the bioaccessibility of monomeric HCA was low, the total phenolic compounds and antioxidant capacity increased during the digestion simulation due to the thermal processes of extrusion and boiling. Extrusion and boiling could be utilized to produce food based on sorghum bran with biological potential.

Modelling Polymer Deformation during 3D Printing

NASA Astrophysics Data System (ADS)

McIlroy, Claire; Olmsted, Peter

Three-dimensional printing has the potential to transform manufacturing processes, yet improving the strength of printed parts, to equal that of traditionally-manufactured parts, remains an underlying issue. The fused deposition modelling technique involves melting a thermoplastic, followed by layer-by-layer extrusion to fabricate an object. The key to ensuring strength at the weld between layers is successful inter-diffusion. However, prior to welding, both the extrusion process and the cooling temperature profile can significantly deform the polymer micro-structure and, consequently, how well the polymers are able to ``re-entangle'' across the weld. In particular, polymer alignment in the flow can cause de-bonding of the layers and create defects. We have developed a simple model of the non-isothermal extrusion process to explore the effects that typical printing conditions and material rheology have on the conformation of a polymer melt. In particular, we incorporate both stretch and orientation using the Rolie-Poly constitutive equation to examine the melt structure as it flows through the nozzle, the subsequent alignment with the build plate and the resulting deformation due to the fixed nozzle height, which is typically less than the nozzle radius.

Rheological properties of wood polymer composites and their role in extrusion

NASA Astrophysics Data System (ADS)

Duretek, I.; Schuschnigg, S.; Gooneie, A.; Langecker, G. R.; Holzer, C.

2015-04-01

The influence of the rheological behaviour of PP based wood plastic composites (WPC) has been investigated in this research by means of a high pressure capillary rheometer incorporating dies having different geometries. The rheological experiments were performed using slit and round dies. The influence of moisture content on the flow properties of the WPC has been investigated as well. It was observed that higher moisture contents lead to wall slippage effect. Furthermore, measured viscosity data have been used in flow simulation of an extrusion profile die. Also, the influence of different rheological models on the simulation results is demonstrated. This research work presents a theoretical and experimental study on the measurement and prediction of the die pressure in the extrusion process of wood-plastic composite (WPC).

Osmotic mechanism of the loop extrusion process

NASA Astrophysics Data System (ADS)

Yamamoto, Tetsuya; Schiessel, Helmut

2017-09-01

The loop extrusion theory assumes that protein factors, such as cohesin rings, act as molecular motors that extrude chromatin loops. However, recent single molecule experiments have shown that cohesin does not show motor activity. To predict the physical mechanism involved in loop extrusion, we here theoretically analyze the dynamics of cohesin rings on a loop, where a cohesin loader is in the middle and unloaders at the ends. Cohesin monomers bind to the loader rather frequently and cohesin dimers bind to this site only occasionally. Our theory predicts that a cohesin dimer extrudes loops by the osmotic pressure of cohesin monomers on the chromatin fiber between the two connected rings. With this mechanism, the frequency of the interactions between chromatin segments depends on the loading and unloading rates of dimers at the corresponding sites.

Development of Replacements for Phoscoating Used in Forging, Extrusion and Metal Forming Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerry Barnett

2003-03-01

Many forging, extrusion, heading and other metal forming processes use graphite-based lubricants, phosphate coatings, and other potentially hazardous or harmful substances to improve the tribology of the metal forming process. The application of phosphate-based coatings has long been studied to determine if other synthetic ''clean'' lubricants could provide the same degree of protection afforded by phoscoatings and its formulations. So far, none meets the cost and performance objectives provided by phoscoatings as a general aid to the metal forming industry. In as much as phoscoatings and graphite have replaced lead-based lubricants, the metal forming industry has had previous experience withmore » a legislated requirement to change processes. However, without a proactive approach to phoscoating replacement, many metal forming processes could find themselves without a cost effective tribology material necessary for the metal forming process« less

Properties of Extruded PS-212 Type Self-Lubricating Materials

NASA Technical Reports Server (NTRS)

Waters, W. J.; Sliney, H. E.; Soltis, R. F.

1993-01-01

Research has been underway at the NASA Lewis Research Center since the 1960's to develop high temperature, self-lubricating materials. The bulk of the research has been done in-house by a team of researchers from the Materials Division. A series of self-lubricating solid material systems has been developed over the years. One of the most promising is the composite material system referred to as PS-212 or PM-212. This material is a powder metallurgy product composed of metal bonded chromium carbide and two solid lubricating materials known to be self-lubricating over a wide temperature range. NASA feels this material has a wide potential in industrial applications. Simplified processing of this material would enhance its commercial potential. Processing changes have the potential to reduce processing costs, but tribological and physical properties must not be adversely affected. Extrusion processing has been employed in this investigation as a consolidation process for PM-212/PS-212. It has been successful in that high density bars of EX-212 (extruded PM-212) can readily be fabricated. Friction and strength data indicate these properties have been maintained or improved over the P.M. version. A range of extrusion temperatures have been investigated and tensile, friction, wear, and microstructural data have been obtained. Results indicate extrusion temperatures are not critical from a densification standpoint, but other properties are temperature dependent.

Organic materials for ceramic molding processes

NASA Technical Reports Server (NTRS)

Saito, K.

1984-01-01

Ceramic molding processes are examined. Binders, wetting agents, lubricants, plasticizers, surface active agents, dispersants, etc., for pressing, rubber pressing, sip casting, injection casting, taping, extrusion, etc., are described, together with forming machines.

Antioxidant potential and quality characteristics of vegetable-enriched corn-based extruded snacks.

PubMed

Bisharat, G I; Lazou, A E; Panagiotou, N M; Krokida, M K; Maroulis, Z B

2015-07-01

Phenolic content, antioxidant activity and sensory characteristics of vegetable-enriched extrudates were investigated as a result of extrusion conditions, including extrusion temperature (140-180 °C), screw rotation speed (150-250 rpm) and feed moisture content (14-19 % w.b.). Broccoli flour and olive paste was used in mixtures with corn flour at a ratio of 4 to 10 % (broccoli/corn) and 4 to 8 % (olive paste/corn). A simple power model was developed for the prediction of phenolic content and antioxidant activity of extrudates by extrusion conditions and feed composition. Phenolic content and antioxidant activity of broccoli enriched extrudates increased with extrusion temperature and broccoli addition and decreased with feed moisture content. The antioxidant activity of olive paste extrudates increased with material ratio and decreased with feed moisture content and screw rotation. Sensory porosity, homogenous structure, crispness, cohesiveness and melting decreased with feed moisture content, while the latter increased the mealy flavor and hardness of extrudates. Acceptable snacks containing broccoli flour or olive paste can be produced by selecting the appropriate process conditions.

Manufacture of gradient micro-structures of magnesium alloys using two stage extrusion dies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hwang, Yeong-Maw; Huang, Tze-Hui; Alexandrov, Sergei

2013-12-16

This paper aims to manufacture magnesium alloy metals with gradient micro-structures using hot extrusion process. The extrusion die was designed to have a straight channel part combined with a conical part. Materials pushed through this specially-designed die generate a non-uniform velocity distribution at cross sections inside the die and result in different strain and strain rate distributions. Accordingly, a gradient microstructure product can be obtained. Using the finite element analysis, the forming temperature, effective strain, and effective strain rate distributions at the die exit were firstly discussed for various inclination angles in the conical die. Then, hot extrusion experiments withmore » a two stage die were conducted to obtain magnesium alloy products with gradient micro-structures. The effects of the inclination angle on the grain size distribution at cross sections of the products were also discussed. Using a die of an inclination angle of 15°, gradient micro-structures of the grain size decreasing gradually from 17 μm at the center to 4 μm at the edge of product were achieved.« less

In vitro biodegradation behavior, mechanical properties, and cytotoxicity of biodegradable Zn–Mg alloy

PubMed Central

Gong, Haibo; Wang, Kun; Strich, Randy; Zhou, Jack G.

2017-01-01

Zinc–Magnesium (Zn–Mg) alloy as a novel biodegradable metal holds great potential in biodegradable implant applications as it is more corrosion resistant than Magnesium (Mg). However, the mechanical properties, biodegradation uniformity, and cytotoxicity of Zn–Mg alloy remained as concerns. In this study, hot extrusion process was applied to Zn–1 wt % Mg (Zn–1Mg) to refine its microstructure. Effects of hot extrusion on biodegradation behavior and mechanical properties of Zn–1Mg were investigated in comparison with Mg rare earth element alloy WE43. Metallurgical analysis revealed significant grain size reduction, and immersion test found that corrosion rates of WE43 and Zn–1Mg were reduced by 35% and 57%, respectively after extrusion. Moreover, hot extrusion resulted in a much more uniform biodegradation in extruded Zn–1Mg alloy and WE43. In vitro cytotoxicity test results indicated that Zn–1Mg alloy was biocompatible. Therefore, hot extruded Zn–1Mg with homogenous microstructure, uniform as well as slow degradation, improved mechanical properties, and good biocompatibility was believed to be an excellent candidate material for load-bearing biodegradable implant application. PMID:25581552

Loss from harlequin ducks of abdominally implanted radio transmitters equipped with percutaneous antennas

USGS Publications Warehouse

Mulcahy, D.M.; Esler, Daniel N.; Stoskopf, M.K.

1999-01-01

We documented extrusion and loss of abdominally implanted radio transmitters with percutaneous antennas from adult female Harlequin Ducks (Histrionicus histrionicus). Birds were captured during wing molt (late August to mid-September) in 1995-1997. Of 44 Harlequin Ducks implanted with radios and recaptured, 7 (16%) had lost their transmitters and 5 (11%) had radios in the process of extruding. Most (11 of 12) extrusions and losses occurred in birds implanted with radios in 1996 and recaptured in 1997. We suggest that transmitter extrusions and losses were due largely to changes in transmitter design made between 1095 and 1996. Transmitters implanted in 1996 were cylindrical rather than spherical, had a flat end with an abrupt edge, and the lower portion of the antenna was reinforced. Radio losses occurred after the 7-mo monitoring period and caused no apparent harm to the birds. Investigators using implanted radios with percutaneous antennas for long-term projects should be aware of the potential for radio extrusion and should minimize the problem by using transmitters that have no sharp edges and that are wide, rather than narrow.

PKA-regulated VASP phosphorylation promotes extrusion of transformed cells from the epithelium

PubMed Central

Anton, Katarzyna A.; Sinclair, John; Ohoka, Atsuko; Kajita, Mihoko; Ishikawa, Susumu; Benz, Peter M.; Renne, Thomas; Balda, Maria; Matter, Karl; Fujita, Yasuyuki

2014-01-01

ABSTRACT At the early stages of carcinogenesis, transformation occurs in single cells within tissues. In an epithelial monolayer, such mutated cells are recognized by their normal neighbors and are often apically extruded. The apical extrusion requires cytoskeletal reorganization and changes in cell shape, but the molecular switches involved in the regulation of these processes are poorly understood. Here, using stable isotope labeling by amino acids in cell culture (SILAC)-based quantitative mass spectrometry, we have identified proteins that are modulated in transformed cells upon their interaction with normal cells. Phosphorylation of VASP at serine 239 is specifically upregulated in RasV12-transformed cells when they are surrounded by normal cells. VASP phosphorylation is required for the cell shape changes and apical extrusion of Ras-transformed cells. Furthermore, PKA is activated in Ras-transformed cells that are surrounded by normal cells, leading to VASP phosphorylation. These results indicate that the PKA–VASP pathway is a crucial regulator of tumor cell extrusion from the epithelium, and they shed light on the events occurring at the early stage of carcinogenesis. PMID:24963131

Factors Contributing to Pilot Valve Fuel Seal Extrusion in Orbiter PRCS Thrusters

NASA Technical Reports Server (NTRS)

Waller, J.M.; Saulsberry, R.L.; Albright, John D.

2000-01-01

Extrusion of the polytetrafluoroethylene (PTFE) pilot seal used in the monomethylhydrazine (fuel) valve of the Orbiter Primary Reaction Control System (PRCS) thrusters has been implicated in numerous on-orbit thruster failures and on-ground valve failures. Two extrusion mechanisms have been proposed, one or both may be occurring. The first mechanism is attributed to thermal expansion mismatch between adjacent PTFE and metal parts used in the fuel valve, and is referred to as thermal extrusion. The second mechanism is attributed to nitrogen tetroxide (oxidizer) leakage from the adjacent oxidizer valve on the same thruster during ground turnaround, and is referred to as oxidizer-induced extrusion. Model calculations of PTFE pilot seal in an exact pilot valve configuration show that extrusion can be caused by differential thermal expansion, without the intervening influence of oxidizer. Experimental data on semitrapped PTFE and TFM (modified PTFE) specimens simulating a fuel pilot valve configuration show that thermal extrusion 1) is incremental and irreversible, 2) increases with the size of the thermal excursion, 3) decreases with successive thermal cycling, and 4) is accompanied by gap formation. Both PTFE and TFM exhibit a higher affinity for oxidizer than fuel. The property changes associated with oxidizer uptake may explain why oxidizer seals do not exhibit extrusion. Impression replicas of fuel pilot seals removed from the Orbiter fleet show two types of extrusion: extrusion of the entire seal (loaded extrusion), or extrusion of non-sealing surface (unloaded extrusion). Both extrusion types may arise from differences in service history, rather than in failure mechanism. The plausibility oxidizer-induced extrusion was evaluated. Preliminary calculations suggest that enough energy, heat, or gas may be liberated under certain operational scenarios to cause catastrophic extrusion. However, given the lack of supporting data, conclusions implicating oxidizer leakage as a factor in extrusion must be made with caution.

Downstream processing from hot-melt extrusion towards tablets: A quality by design approach.

PubMed

Grymonpré, W; Bostijn, N; Herck, S Van; Verstraete, G; Vanhoorne, V; Nuhn, L; Rombouts, P; Beer, T De; Remon, J P; Vervaet, C

2017-10-05

Since the concept of continuous processing is gaining momentum in pharmaceutical manufacturing, a thorough understanding on how process and formulation parameters can impact the critical quality attributes (CQA) of the end product is more than ever required. This study was designed to screen the influence of process parameters and drug load during HME on both extrudate properties and tableting behaviour of an amorphous solid dispersion formulation using a quality-by-design (QbD) approach. A full factorial experimental design with 19 experiments was used to evaluate the effect of several process variables (barrel temperature: 160-200°C, screw speed: 50-200rpm, throughput: 0.2-0.5kg/h) and drug load (0-20%) as formulation parameter on the hot-melt extrusion (HME) process, extrudate and tablet quality of Soluplus ® -Celecoxib amorphous solid dispersions. A prominent impact of the formulation parameter on the CQA of the extrudates (i.e. solid state properties, moisture content, particle size distribution) and tablets (i.e. tabletability, compactibility, fragmentary behaviour, elastic recovery) was discovered. The resistance of the polymer matrix to thermo-mechanical stress during HME was confirmed throughout the experimental design space. In addition, the suitability of Raman spectroscopy as verification method for the active pharmaceutical ingredient (API) concentration in solid dispersions was evaluated. Incorporation of the Raman spectroscopy data in a PLS model enabled API quantification in the extrudate powders with none of the DOE-experiments resulting in extrudates with a CEL content deviating>3% of the label claim. This research paper emphasized that HME is a robust process throughout the experimental design space for obtaining amorphous glassy solutions and for tabletting of such formulations since only minimal impact of the process parameters was detected on the extrudate and tablet properties. However, the quality of extrudates and tablets can be optimized by adjusting specific formulations parameters (e.g. drug load). Copyright © 2017 Elsevier B.V. All rights reserved.

Numerical simulation of hot-melt extrusion processes for amorphous solid dispersions using model-based melt viscosity.

PubMed

Bochmann, Esther S; Steffens, Kristina E; Gryczke, Andreas; Wagner, Karl G

2018-03-01

Simulation of HME processes is a valuable tool for increased process understanding and ease of scale-up. However, the experimental determination of all required input parameters is tedious, namely the melt rheology of the amorphous solid dispersion (ASD) in question. Hence, a procedure to simplify the application of hot-melt extrusion (HME) simulation for forming amorphous solid dispersions (ASD) is presented. The commercial 1D simulation software Ludovic ® was used to conduct (i) simulations using a full experimental data set of all input variables including melt rheology and (ii) simulations using model-based melt viscosity data based on the ASDs glass transition and the physical properties of polymeric matrix only. Both types of HME computation were further compared to experimental HME results. Variation in physical properties (e.g. heat capacity, density) and several process characteristics of HME (residence time distribution, energy consumption) among the simulations and experiments were evaluated. The model-based melt viscosity was calculated by using the glass transition temperature (T g ) of the investigated blend and the melt viscosity of the polymeric matrix by means of a T g -viscosity correlation. The results of measured melt viscosity and model-based melt viscosity were similar with only few exceptions, leading to similar HME simulation outcomes. At the end, the experimental effort prior to HME simulation could be minimized and the procedure enables a good starting point for rational development of ASDs by means of HME. As model excipients, Vinylpyrrolidone-vinyl acetate copolymer (COP) in combination with various APIs (carbamazepine, dipyridamole, indomethacin, and ibuprofen) or polyethylene glycol (PEG 1500) as plasticizer were used to form the ASDs. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of printed planar electromagnetic coils using digital extrusion and roll-to-roll flexographic processes

NASA Astrophysics Data System (ADS)

Rickard, Scott

Electromagnets are a crucial component in a wide range of more complex electrical devices due to their ability to turn electrical energy into mechanical energy and vice versa. The trend for electronics becoming smaller and lighter has led to increased interest in using flat, planar electromagnetic coils, which have been shown to perform better at scaled down sizes. The two-dimensional geometry of a planar electromagnetic coil yields itself to be produced by a roll-to-roll additive manufacturing process. The emergence of the printed electronics field, which uses traditional printing processes to pattern functional inks, has led to new methods of mass-producing basic electrical components. The ability to print a planar electromagnetic coil using printed electronics could rival the traditional subtractive and semi-subtractive PCB process of manufacturing. The ability to print lightweight planar electromagnetic coils on flexible substrates could lead to their inclusion into intelligent packaging applications and could have specific use in actuating devices, transformers, and electromagnetic induction applications such as energy harvesting or wireless charging. In attempts to better understand the limitations of printing planar electromagnetic coils, the effect that the design parameters of the planar coils have on the achievable magnetic field strength were researched. A comparison between prototyping methods of digital extrusion and manufacturing scale flexographic printing are presented, discussing consistency in the printed coils and their performance in generating magnetic fields. A method to predict the performance of these planar coils is introduced to allow for design within required needs of an application. Results from the research include a demonstration of a printed coil being used in a flat speaker design, working off of actuating principles.

Exposure to rubber fume and rubber process dust in the general rubber goods, tyre manufacturing and retread industries.

PubMed

Dost, A A; Redman, D; Cox, G

2000-08-01

This study assesses the current patterns and levels of exposure to rubber fume and rubber process dust in the British rubber industry and compares and contrasts the data obtained from the general rubber goods (GRG), retread tire (RT) and new tire (NT) sectors. A total of 179 rubber companies were visited and data were obtained from 52 general rubber goods, 29 retread tire and 7 new tire manufacturers. The survey was conducted using a questionnaire and included a walk-through inspection of the workplace to assess the extent of use of control measures and the nature of work practices being employed. The most recent (predominantly 1995-97) exposure monitoring data for rubber fume and rubber process dust were obtained from these companies; no additional sampling was conducted for the purpose of this study. In addition to the assessment of exposure data, evaluation of occupational hygiene reports for the quality of information and advice was also carried out.A comparison of the median exposures for processes showed that the order of exposure to rubber fume (E, in mg m(-3)) is: E(moulding) (0.40) approximately E(extrusion) (0.33)>E(milling) (0.18) for GRG; E(press) (0. 32)>E(extrusion) (0.19)>E(autoclave) (0.10) for RT; and E(press) (0. 22) approximately E(all other) (0.22) for NT. The order of exposure to rubber fume between sectors was E(GRG) (0.40)>E(RT) (0.32)>E(NT) (0.22). Median exposures to rubber process dust in the GRG was E(weighing) (4.2)>E(mixing) (1.2) approximately E(milling) (0.8) approximately E(extrusion) (0.8) and no significant difference (P=0. 31) between GRG and NT sectors. The findings compare well with the study carried out in the Netherlands [Kromhout et al. (1994), Annals of Occupational Hygiene 38(1), 3-22], and it is suggested that the factors governing the significant differences noted between the three sectors relate principally to the production and task functions and also to the extent of controls employed. Evaluation of occupational hygiene reports indicated a number of shortcomings including lack of suitable and sufficient information with regard to sampling and analytical methods in use, poor sampling strategy, lack of appreciation regarding true rubber process dust, and a poor understanding of the principles of control for substances assigned maximum exposure limits.

Intra-continental subduction and contemporaneous lateral extrusion of the upper plate: insights into Alps-Adria interactions

NASA Astrophysics Data System (ADS)

van Gelder, Inge; Willingshofer, Ernst; Sokoutis, Dimitrios; Cloetingh, Sierd

2017-04-01

A series of physical analogue experiments were performed to simulate intra-continental subduction contemporaneous with lateral extrusion of the upper plate to study the interferences between these two processes at crustal levels and in the lithospheric mantle. The lithospheric-scale models are specifically designed to represent the collision of the Adriatic microplate with the Eastern Alps, simulated by an intra-continental weak zone to initiate subduction and a weak confined margin perpendicular to the direction of convergence in order to allow for extrusion of the lithosphere. The weak confined margin is the analog for the opening of the Pannonian back-arc basin adjacent to the Eastern Alps with the direction of extension perpendicular to the strike of the orogen. The models show that intra-continental subduction and coeval lateral extrusion of the upper plate are compatible processes. The obtained deformation structures within the extruding region are similar compared to the classical setup where lateral extrusion is provoked by lithosphere-scale indentation. In the models a strong coupling across the subduction boundary allows for the transfer of abundant stresses to the upper plate, leading to laterally varying strain regimes that are characterized by crustal thickening near a confined margin and dominated by lateral displacement of material near a weak lateral confinement. During ongoing convergence the strain regimes propagate laterally, thereby creating an area of overlap characterized by transpression. In models with oblique subduction, with respect to the convergence direction, less deformation of the upper plate is observed and as a consequence the amount of lateral extrusion decreases. Additionally, strain is partitioned along the oblique plate boundary leading to less subduction in expense of right lateral displacement close to the weak lateral confinement. Both oblique and orthogonal subduction models have a strong resemblance to lateral extrusion tectonics of the Eastern Alps, where subduction of the adjacent Adriatic plate beneath the Eastern Alps is debated. Our results highlight that both indentation and subduction of Adria are valid collisional mechanisms to provoke lateral extrusion-type deformation within the Eastern Alps lithosphere, i.e. the upper plate. Moreover, the insights suggest that the Oligocene to Late Miocene structural evolution of the Eastern Alps is best described by phases of oblique and subsequent orthogonal subduction which is in line with Miocene rotations of the Adriatic plate. Furthermore, oblique subduction of the Adriatic plate provides a viable mechanism to explain the rapid decrease in slab length beneath the Eastern Alps towards the Pannonian Basin, also implying that the Adriatic slab can behave and form independently with regards to the adjacent subduction of Adria beneath the Dinarides.

Perforated plates for cryogenic regenerators and method of fabrication

DOEpatents

Hendricks, J.B.

1994-03-29

Perforated plates having very small holes with a uniform diameter throughout the plate thickness are prepared by a [open quotes]wire drawing[close quotes] process in which a billet of sacrificial metal is disposed in an extrusion can of the plate metal, and the can is extruded and restacked repeatedly, converting the billet to a wire of the desired hole diameter. At final size, the rod is then sliced into wafers, and the wires are removed by selective etching. This process is useful for plate metals of interest for high performance regenerator applications, in particular, copper, niobium, molybdenum, erbium, and other rare earth metals. Er[sub 3]Ni, which has uniquely favorable thermophysical properties for such applications, may be incorporated in regions of the plates by providing extrusion cans containing erbium and nickel metals in a stacked array with extrusion cans of the plate metal, which may be copper. The array is heated to convert the erbium and nickel metals to Er[sub 3]Ni. Perforated plates having two sizes of perforations, one of which is small enough for storage of helium, are also disclosed. 10 figures.

Perforated plates for cryogenic regenerators and method of fabrication

DOEpatents

Hendricks, John B.

1994-01-01

Perforated plates (10) having very small holes (14) with a uniform diameter throughout the plate thickness are prepared by a "wire drawing" process in which a billet of sacrificial metal is disposed in an extrusion can of the plate metal, and the can is extruded and restacked repeatedly, converting the billet to a wire of the desired hole diameter. At final size, the rod is then sliced into wafers, and the wires are removed by selective etching. This process is useful for plate metals of interest for high performance regenerator applications, in particular, copper, niobium, molybdenum, erbium, and other rare earth metals. Er.sub.3 Ni, which has uniquely favorable thermophysical properties for such applications, may be incorporated in regions of the plates by providing extrusion cans (20) containing erbium and nickel metals in a stacked array (53) with extrusion cans of the plate metal, which may be copper. The array is heated to convert the erbium and nickel metals to Er.sub.3 Ni. Perforated plates having two sizes of perforations (38, 42), one of which is small enough for storage of helium, are also disclosed.

Final Technical Report - Advanced Optical Sensors to Minimize Energy Consumption in Polymer Extrusion Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Susan J. Foulk

Project Objective: The objectives of this study are to develop an accurate and stable on-line sensor system to monitor color and composition on-line in polymer melts, to develop a scheme for using the output to control extruders to eliminate the energy, material and operational costs of off-specification product, and to combine or eliminate some extrusion processes. Background: Polymer extrusion processes are difficult to control because the quality achieved in the final product is complexly affected by the properties of the extruder screw, speed of extrusion, temperature, polymer composition, strength and dispersion properties of additives, and feeder system properties. Extruder systemsmore » are engineered to be highly reproducible so that when the correct settings to produce a particular product are found, that product can be reliably produced time after time. However market conditions often require changes in the final product, different products or grades may be processed in the same equipment, and feed materials vary from lot to lot. All of these changes require empirical adjustment of extruder settings to produce a product meeting specifications. Optical sensor systems that can continuously monitor the composition and color of the extruded polymer could detect process upsets, drift, blending oscillations, and changes in dispersion of additives. Development of an effective control algorithm using the output of the monitor would enable rapid corrections for changes in materials and operating conditions, thereby eliminating most of the scrap and recycle of current processing. This information could be used to identify extruder systems issues, diagnose problem sources, and suggest corrective actions in real-time to help keep extruder system settings within the optimum control region. Using these advanced optical sensor systems would give extruder operators real-time feedback from their process. They could reduce the amount of off-spec product produced and significantly reduce energy consumption. Also, because blending and dispersion of additives and components in the final product could be continuously verified, we believe that, in many cases, intermediate compounding steps could be eliminated (saving even more time and energy).« less

Oblique Northeastward Lateral Extrusion of a Crustal Block in North-central Taiwan: a Mechanism for Syn-tectonic Extension

NASA Astrophysics Data System (ADS)

Gourley, J. R.; Byrne, T.

2005-12-01

An integrated data set of earthquake locations (Taiwan's Central Weather Bureau), focal mechanisms from the Broadband Array of Taiwan Seismicity (BATS), GPS velocities and geologic data are combined to constrain the geometry and kinematics of a crustal block within the metamorphic basement of Taiwan's northeastern Central Range. The active block is bounded by two parallel seismic zones that accommodate uplift and northeastward oblique lateral extrusion. The western shear zone is a region that dips vertically to steeply west and projects generally to the western boundary between the Slate Belt and pre-Tertiary metamorphic basement. BATS focal mechanisms consistently show east-side-up, left-lateral normal displacements. Late-stage geologic structures published previously show left-lateral faulting followed by east-west extension. The eastern shear zone dips vertically to steeply west and projects to the eastern boundary of the metamorphic basement, which correlates with the eastern mountain front in this area. BATS focal mechanisms show west-side-up reverse displacements. The kinematics of these two zones define a crustal scale block that is interpreted to be moving up and northeast towards the Okinawa Trough. The extrusion of this crustal block may be driven in part by the topographic difference between the Central Range and the Okinawa Trough, as well as by the active collision between the Philippine Sea Plate and the Eurasian basement high. This proposed northeastern lateral extrusion mirrors the active lateral extrusion in southwestern Taiwan which is observed on the southern side of the Eurasian basement high collision. The involvement of the basement high in the collision and adjacent regions appears to be an important factor in understanding local structural variations in the arc-continent collision and should be considered in both forward and reverse modeling of Taiwan deformation.

Apical extrusion of debris: a literature review of an inherent occurrence during root canal treatment.

PubMed

Tanalp, J; Güngör, T

2014-03-01

Extrusion of intracanal debris as well as irrigants is a common occurrence during root canal treatment, and no instrument or technique has thoroughly solved this problem. Because flare-ups may arise with any irritation directed towards periapical tissues, a shaping or irrigation technique should minimize the risk of apical extrusion, even though it may not be prevented. There has been a rapid evolution of root canal instruments and irrigation systems through the last decade, and many have been assessed for their debris extrusion potential. The purpose of this review was to identify publications regarding the evaluation of debris, bacteria and irrigant extrusion during root canal treatment. A PubMed, Ovid and MEDLINE search was conducted using the keywords "apical extrusion", "debris extrusion" and "endodontic treatment". The literature search extended over a period of more than 30 years up to 2012. Content of the review was limited to apical extrusion of debris and irrigants, extrusion of liquid by irrigation methods and bacterial extrusion. Issues relevant to apical extrusion were obtained by further search in the reference sections of the retrieved articles. The review provides an update on the current status of apical extrusion. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Predictors of degenerative medial meniscus extrusion: radial component and knee osteoarthritis.

PubMed

Lee, Dae-Hee; Lee, Bum-Sik; Kim, Jong-Min; Yang, Kyung-Sook; Cha, Eun-Jong; Park, Ji-Hun; Bin, Seong-Il

2011-02-01

the purpose of this study was to determine the effect of a radial tear on degenerative medial meniscus posterior horn tear extrusion and to identify predictors of medial meniscus extrusion. we reviewed the records of 102 knees with medial meniscus posterior horn tears and degeneration that underwent a partial meniscectomy. Tears were classified as root (n = 17) and non-root (n = 85) tears, or as radial (n = 46) and non-radial (n = 56) tears. Groups were compared in terms of absolute and relative meniscal extrusion, and the proportion of knees with major (> 3 mm) extrusion. Multiple regression analysis was used to identify predictors of extrusion. the radial group had greater mean absolute (4 ± 1 vs. 3 ± 1 mm, P = 0.001) and relative (31 ± 11 vs. 23 ± 12%, P = 0.031) extrusion than the non-radial group. The radial group also had a greater proportion of major extrusions than the non-radial group (74% vs. 26%; P = 0.016). In contrast, the root tear and non-root tear groups were similar in terms of mean absolute (3 ± 1 vs. 3 ± 1 mm, P = n.s.) and relative (30 ± 7 vs. 26 ± 13%; P = n.s.) extrusion and in terms of proportion with major extrusions (59 vs. 55%; P = n.s.). Extrusion was found to be associated with a similar strength with both the presence of a radial component and the preoperative Kellgren-Lawrence grade. meniscal extrusion was greater and more severe in knees with a radial tear component than in knees without a radial component. The incidence and degree of major extrusion was similar in knees with root tears and non-root tears. A radial component and knee osteoarthritis severity were similarly predictive of absolute and relative extrusion. Meniscal extrusion in osteoarthritic knees was associated not only with degenerative meniscal tear but also with osteoarthritis severity. Therefore, arthroscopic meniscal procedures, especially meniscal repair, should be cautiously considered in patients with meniscal extrusion.

Optical Measurement Technology For Aluminium Extrusions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moe, Per Thomas; Willa-Hansen, Arnfinn; Stoeren, Sigurd

2007-04-07

Optical measurement techniques such as laser scanning, structured light scanning and photogrammetry can be used for accurate shape control for aluminum extrusion and downstream processes. The paper presents the fundamentals of optical shape measurement. Furthermore, it focuses on how full-field in- and off-line shape measurement during pure-bending of aluminum extrusions has been performed with stripe projection (structured light) using white light. Full field shape measurement is difficult to implement industrially, but is very useful as a laboratory tool. For example, it has been clearly shown how moderate internal air pressure (less than 5 bars) can significantly reduce undesirable cross-sectional shapemore » distortions during pure bending, and how buckling of the compressive flange occurs at an early stage. Finally, a stretch-bending set-up with adaptive shape control using internal gas pressure and optical techniques is presented.« less

Alkaline twin-screw extrusion pretreatment for fermentable sugar production.

PubMed

Liu, Chao; van der Heide, Evert; Wang, Haisong; Li, Bin; Yu, Guang; Mu, Xindong

2013-01-01

The inevitable depletion of fossil fuels has resulted in an increasing worldwide interest in exploring alternative and sustainable energy sources. Lignocellulose, which is the most abundant biomass on earth, is widely regarded as a promising raw material to produce fuel ethanol. Pretreatment is an essential step to disrupt the recalcitrance of lignocellulosic matrix for enzymatic saccharification and bioethanol production. This paper established an ATSE (alkaline twin-screw extrusion pretreatment) process using a specially designed twin-screw extruder in the presence of alkaline solution to improve the enzymatic hydrolysis efficiency of corn stover for the production of fermentable sugars. The ATSE pretreatment was conducted with a biomass/liquid ratio of 1/2 (w/w) at a temperature of 99°C without heating equipment. The results indicated that ATSE pretreatment is effective in improving the enzymatic digestibility of corn stover. Sodium hydroxide loading is more influential factor affecting both sugar yield and lignin degradation than heat preservation time. After ATSE pretreatment under the proper conditions (NaOH loading of 0.06 g/g biomass during ATSE and 1 hour heat preservation after extrusion), 71% lignin removal was achieved and the conversions of glucan and xylan in the pretreated biomass can reach to 83% and 89% respectively via subsequent enzymatic hydrolysis (cellulase loading of 20 FPU/g-biomass and substrate consistency of 2%). About 78% of the original polysaccharides were converted into fermentable sugars. With the physicochemical functions in extrusion, the ATSE method can effectively overcome the recalcitrance of lignocellulose for the production of fermentable sugars from corn stover. This process can be considered as a promising pretreatment method due to its relatively low temperature (99°C), high biomass/liquid ratio (1/2) and satisfied total sugar yield (78%), despite further study is needed for process optimization and cost reduction.

Hot melt extrusion versus spray drying: hot melt extrusion degrades albendazole.

PubMed

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.

Study on extrusion process of SiC ceramic matrix

NASA Astrophysics Data System (ADS)

Dai, Xiao-Yuan; Shen, Fan; Ji, Jia-You; Wang, Shu-Ling; Xu, Man

2017-11-01

In this thesis, the extrusion process of SiC ceramic matrix has been systematically studied.The effect of different cellulose content on the flexural strength and pore size distribution of SiC matrix was discussed.Reselts show that with the increase of cellulose content, the flexural strength decreased.The pore size distribution in the sample was 1um-4um, and the 1um-2um concentration was more concentrated. It is found that the cellulose content has little effect on the pore size distribution.When the cellulose content is 7%, the flexural strength of the sample is 40.9Mpa. At this time, the mechanical properties of the sample are the strongest.

Water-assisted extrusion of bio-based PETG/clay nanocomposites

NASA Astrophysics Data System (ADS)

Lee, Naeun; Lee, Sangmook

2018-02-01

Bio-based polyethylene terephthalate glycol-modified (PETG)/clay nanocomposites were prepared using the water-assisted extrusion process. The effects of different types of clay and clay mixing methods (with or without the use of water) and the resulting nanocomposites properties were investigated by measuring the rheological and tensile properties and morphologies. The valuable properties were achieved when Cloisite 30B was mixed in a slurry state. The results of the X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed that the nano-clay was well dispersed within the PETG matrix. This shows that the slurry process could be an effective exfoliation method for many nanocomposites systems as well as for bio-based PETG/clay nanocomposites.

Mathematical modeling of hydromechanical extrusion

NASA Astrophysics Data System (ADS)

Agapitova, O. Yu.; Byvaltsev, S. V.; Zalazinsky, A. G.

2017-12-01

The mathematical modeling of the hydromechanical extrusion of metals through two sequentially installed cone dies is carried out. The optimum parameters of extrusion tools are determined to minimize the extrusion force. A software system has been developed to solve problems of plastic deformation of metals and to provide an optimum design of extrusion tools.

Effects of extrusion variables on the properties of waxy hulless barley extrudates.

PubMed

Köksel, Hamit; Ryu, Gy-Hyung; Başman, Arzu; Demiralp, Hande; Ng, Perry K W

2004-02-01

The objective of this research was to investigate the extrudability of waxy hulless barley flour under various extrusion conditions. Waxy hulless barley flour was processed in a laboratory-scale corotating twin-screw extruder with different levels of feed moisture content (22.3, 26.8, and 30.7%) and die temperature (130, 150, and 170 degrees C) to develop a snack food with high beta-glucan content. The effects of extrusion condition variables (screw configuration, moisture, and temperature) on the system variables (pressure and specific mechanical energy), the extrudate physical properties (sectional expansion index, bulk density), starch gelatinization, pasting properties (cold peak viscosity, trough viscosity, and final viscosity), and beta-glucan contents were determined. Results were evaluated by using response surface methodology. Increased extrusion temperature and feed moisture content resulted in decreases in exit die pressure and specific mechanical energy values. For extrudates extruded under low shear screw configuration (LS), increased barrel temperature decreased sectional expansion index (SEI) values at both low and high moisture contents. The feed moisture seems to have an inverse relationship with SEI over the range studied. Bulk density was higher at higher moisture contents, for both low and high barrel temperatures, for samples extruded under high shear screw configuration (HS) and LS. Cold peak viscosities (CV) were observed in all samples. The CV increased with the increase in extrusion temperature and feed moisture content. Although beta-glucan contents of the LS extrudates were comparable to that of barley flour sample, HS samples had generally lower beta-glucan contents. The extrusion cooking technique seems to be promising for the production of snack foods with high beta-glucan content, especially using LS conditions.

Optimization of porthole die geometrical variables by Taguchi method

NASA Astrophysics Data System (ADS)

Gagliardi, F.; Ciancio, C.; Ambrogio, G.; Filice, L.

2017-10-01

Porthole die extrusion is commonly used to manufacture hollow profiles made of lightweight alloys for numerous industrial applications. The reliability of extruded parts is affected strongly by the quality of the longitudinal and transversal seam welds. According to that, the die geometry must be designed correctly and the process parameters must be selected properly to achieve the desired product quality. In this study, numerical 3D simulations have been created and run to investigate the role of various geometrical variables on punch load and maximum pressure inside the welding chamber. These are important outputs to take into account affecting, respectively, the necessary capacity of the extrusion press and the quality of the welding lines. The Taguchi technique has been used to reduce the number of the required numerical simulations necessary for considering the influence of twelve different geometric variables. Moreover, the Analysis of variance (ANOVA) has been implemented to individually analyze the effect of each input parameter on the two responses. Then, the methodology has been utilized to determine the optimal process configuration individually optimizing the two investigated process outputs. Finally, the responses of the optimized parameters have been verified through finite element simulations approximating the predicted value closely. This study shows the feasibility of the Taguchi technique for predicting performance, optimization and therefore for improving the design of a porthole extrusion process.

Microcapsules loaded with the probiotic Lactobacillus paracasei BGP-1 produced by co-extrusion technology using alginate/shellac as wall material: Characterization and evaluation of drying processes.

PubMed

Silva, Marluci P; Tulini, Fabricio L; Ribas, Marcela M; Penning, Manfred; Fávaro-Trindade, Carmen S; Poncelet, Denis

2016-11-01

Microcapsules containing Lactobacillus paracasei BGP-1 were produced by co-extrusion technology using alginate and alginate-shellac blend as wall materials. Sunflower oil and coconut fat were used as vehicles to incorporate BGP-1 into the microcapsules. The microcapsules were evaluated with regard the particle size, morphology, water activity and survival of probiotics after 60days of storage at room temperature. Fluidized bed and lyophilization were used to dry the microcapsules and the effect of these processes on probiotic viability was also evaluated. Next, dried microcapsules were exposed to simulated gastrointestinal fluids to verify the survival of BGP-1. Microcapsules dried by fluidized bed had spherical shape and robust structures, whereas lyophilized microcapsules had porous and fragile structures. Dried microcapsules presented a medium size of 0.71-0.86mm and a w ranging from 0.14 to 0.36, depending on the drying process. When comparing the effects of drying processes on BGP-1 viability, the fluidized bed was less aggressive than lyophilization. The alginate-shellac blend combined with coconut fat as core effectively protected the encapsulated probiotic under simulated gastrointestinal conditions. Thus, the production of microcapsules by co-extrusion followed by drying using the fluidized bed is a promising strategy for protection of probiotic cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microstructural Characteristic of the Al-Fe-Cu Alloy During High-Speed Repetitive Continuous Extrusion Forming

NASA Astrophysics Data System (ADS)

Hu, Jiamin; Teng, Jie; Ji, Xiankun; Kong, Xiangxin; Jiang, Fulin; Zhang, Hui

2016-11-01

High-speed repetitive continuous extrusion forming process (R-Conform process) was performed on the Al-Fe-Cu alloy. The microstructural evolution and mechanical properties were studied by x-ray diffraction, electron backscatter diffraction, transmission electron microscopy and tensile testing. The results show that a significant improvement of tensile ductility concurs with a considerable loss of tensile strength before four passes, after that the process on mechanical properties variation tends to be steady, indicating an accelerated mechanical softening occurs when comparing to low-speed R-Conform process. Microstructure characterization indicates that the accumulated strain promotes the transformation of low angle boundaries to high angle boundaries, thus leading to the acceleration of continuous dynamic recrystallization process, and the precipitates are broken, spheroidized and homogeneously distribute in Al matrix as increasing R-Conform passes. Massive microshear bands are observed after initial passes of R-Conform process, which may promote continuous dynamic recrystallization and further grain refinement during high-speed R-Conform process.

75 FR 57441 - Aluminum Extrusions From the People's Republic of China: Alignment of Final Countervailing Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-21

... DEPARTMENT OF COMMERCE International Trade Administration [C-570-968] Aluminum Extrusions From the... countervailing duty investigation of aluminum extrusions from the People's Republic of China (PRC) with the final... antidumping duty investigations on aluminum extrusions from the PRC. See Aluminum Extrusions from the People's...

Moisture sorption characteristics of extrusion-cooked starch protective loose-fill cushioning foams

NASA Astrophysics Data System (ADS)

Combrzyński, Maciej; Mościcki, Leszek; Kwaśniewska, Anita; Oniszczuk, Tomasz; Wójtowicz, Agnieszka; Sołowiej, Bartosz; Gładyszewska, Bożena; Muszyński, Siemowit

2017-10-01

The aim of this work was to determine the water vapour sorption properties of thermoplastic starch filling foams processed by extrusion-cooking technique from various combinations of potato starch and two foaming agents: poly(vinyl) alcohol and Plastronfoam, in amount of 1, 2 and 3% each. Foams were processed with the single screw extruder-cooker at two different screw rotational speeds 100 and 130 r.p.m. The sorption isotherms of samples were determined and described using the Guggenheim-Anderson-de Boer model. Also, the kinetics of water vapour adsorption by foams, as a function of time, was measured and fitted with Peleg model. On the basis of the analysis the influence of the applied foaming agents, as well as the technological parameters of extrusion-cooking process in relation to water vapour adsorption by thermoplastic starch foams was demonstrated. There was no difference between the shapes of the isotherms for poly(vinyl) alcohol foams while for Plastronfoam foams a notable difference among foams extruded at 100 r.p.m. was observed in the regions of low and high humidity content. The analysis of the Guggenheim-Anderson-de Boer model parameters showed that the water molecules were less strongly bound with the foam surface when extruded at a lower screw speed.

Grain refinement and texture development of cast bismuth-antimony alloy via severe plastic deformation

NASA Astrophysics Data System (ADS)

Im, Jae-Taek

The purpose of this work was to study learn about grain refinement mechanisms and texture development in cast n-type Bi90Sb10 alloy caused by severe plastic deformation. The practical objective is to produce a fine grained and textured microstructure in Bi90Sb10 alloy with enhanced thermoelectric performance and mechanical strength. In the study, twelve millimeter diameter cast bars of Bi90Sb 10 alloy were encapsulated in square cross section aluminum 6061 alloy containers. The composite bars were equal channel angular (ECAE) extruded through a 90 degree angle die at high homologous temperature. Various extrusion conditions were studied including punch speed (0.1, 0.3 and 0.6 in/min), extrusion temperature (220, 235 and 250°C), number of extrusion passes (1, 2 and 4), route (A, BC and C), and exit channel area reduction ratio (half and quarter area of inlet channel). The affect of an intermediate long term heat treatment (for 100 hours at 250°C under 10-3 torr vacuum) was explored. Processed materials were characterized by optical microscopy, x-ray diffraction, energy dispersive spectroscopy, wavelength dispersive spectroscopy and scanning electron microscopy. Texture was analyzed using the {006} reflection plane to identify the orientation of the basal poles in processed materials. The cast grains were irregularly shaped, had a grain size of hundreds-of-microns to millimeters, and showed inhomogeneous chemical composition. Severe plastic deformation refines the cast grains through dynamic recrystallization and causes the development of a bimodal microstructure consisting of fine grains (5-30 micron) and coarse grains (50-300 micron). ECAE processing of homogenizied Bi-Sb alloy causes grain refinement and produces a more uniform microstructure. Texture results show that ECAE route C processing gives a similar or slightly stronger texture than ECAE route A processing. In both cases, the basal-plane poles become aligned with the shear direction. Reduction area exit channel extrusion is more effective for both grain refinement and texture enhancement than simple ECAE processing.

Salmonella Inactivation During Extrusion of an Oat Flour Model Food.

PubMed

Anderson, Nathan M; Keller, Susanne E; Mishra, Niharika; Pickens, Shannon; Gradl, Dana; Hartter, Tim; Rokey, Galen; Dohl, Christopher; Plattner, Brian; Chirtel, Stuart; Grasso-Kelley, Elizabeth M

2017-03-01

Little research exists on Salmonella inactivation during extrusion processing, yet many outbreaks associated with low water activity foods since 2006 were linked to extruded foods. The aim of this research was to study Salmonella inactivation during extrusion of a model cereal product. Oat flour was inoculated with Salmonella enterica serovar Agona, an outbreak strain isolated from puffed cereals, and processed using a single-screw extruder at a feed rate of 75 kg/h and a screw speed of 500 rpm. Extrudate samples were collected from the barrel outlet in sterile bags and immediately cooled in an ice-water bath. Populations were determined using standard plate count methods or a modified most probable number when populations were low. Reductions in population were determined and analyzed using a general linear model. The regression model obtained for the response surface tested was Log (N R /N O ) = 20.50 + 0.82T - 141.16a w - 0.0039T 2 + 87.91a w 2 (R 2 = 0.69). The model showed significant (p < 0.05) linear and quadratic effects of a w and temperature and enabled an assessment of critical control parameters. Reductions of 0.67 ± 0.14 to 7.34 ± 0.02 log CFU/g were observed over ranges of a w (0.72 to 0.96) and temperature (65 to 100 °C) tested. Processing conditions above 82 °C and 0.89 a w achieved on average greater than a 5-log reduction of Salmonella. Results indicate that extrusion is an effective means for reducing Salmonella as most processes commonly employed to produce cereals and other low water activity foods exceed these parameters. Thus, contamination of an extruded food product would most likely occur postprocessing as a result of environmental contamination or through the addition of coatings and flavorings. © 2017 Institute of Food Technologists®.

Maintaining High Strength in Mg-LPSO Alloys with Low Yttrium Content Using Severe Plastic Deformation.

PubMed

Garces, Gerardo; Cabeza, Sandra; Barea, Rafael; Pérez, Pablo; Adeva, Paloma

2018-05-05

Alternative processing routes such as powder metallurgy, the extrusion of recycled chips, or equal channel angular pressing (ECAP) have been considered for effective methods of maintaining the high mechanical strength of Mg-Y-Zn alloys containing long-period stacking ordered structures with respect to the alloy processed by the conventional extrusion of as-cast ingots with the advantage of minimizing the yttrium content. A yield stress similar to that found for extruded Mg 97 Y₂Zn₁ alloy can be attained with only half of the usual yttrium and zinc additions thanks to the grain refinement induced by ECAP processing. The properties of Mg 98.5 Y₁Zn 0.5 subjected to ECAP are maintained up to 200 °C, but superplastic behavior is found above this temperature when the alloy is processed through a powder metallurgy route.

Chemical Changes in Carbohydrates Produced by Thermal Processing.

ERIC Educational Resources Information Center

Hoseney, R. Carl

1984-01-01

Discusses chemical changes that occur in the carbohydrates found in food products when these products are subjected to thermal processing. Topics considered include browning reactions, starch found in food systems, hydrolysis of carbohydrates, extrusion cooking, processing of cookies and candies, and alterations in gums. (JN)

Experimental study on combined cold forging process of backward cup extrusion and piercing

NASA Astrophysics Data System (ADS)

Henry, Robinson; Liewald, Mathias

2018-05-01

A reduction in material usage of cold forged components while maintaining the functional requirements can be achieved using hollow or tubular preforms. These preforms are used to meet lightweight requirements and to decrease production costs of cold formed components. To increase production efficiency in common multi-stage cold forming processes, manufacturing of hollow preforms by combining the processes backward cup extrusion and piercing was established and will be discussed in this paper. Corresponding investigations and experimental studies are reported in this article. The objectives of the experimental investigations have been the detection of significant process parameters, determination of process limits for the combined processes and validation of the numerical investigations. In addition, the general influence concerning surface quality and diameter tolerance of hollow performs are discussed in this paper. The final goal is to summarize a guideline for industrial application, moreover, to transfer the knowledge to industry, as regards what are required part geometries to reduce the number of forming stages as well as tool cost.

Extrusion of xylans extracted from corn cobs into biodegradable polymeric materials.

PubMed

Bahcegul, Erinc; Akinalan, Busra; Toraman, Hilal E; Erdemir, Duygu; Ozkan, Necati; Bakir, Ufuk

2013-12-01

Solvent casting technique, which comprises multiple energy demanding steps including the dissolution of a polymer in a solvent followed by the evaporation of the solvent from the polymer solution, is currently the main technique for the production of xylan based polymeric materials. The present study shows that sufficient water content renders arabinoglucuronoxylan (AGX) polymers extrudable, enabling the production of AGX based polymeric materials in a single step via extrusion, which is economically advantageous to solvent casting process for mass production. AGX polymers with water content of 27% were found to yield extrudates at an extrusion temperature of 90°C. The extruded strips showed very good mechanical properties with an ultimate tensile strength of 76 ± 6 MPa and elongation at break value of 35 ± 8%, which were superior to the mechanical properties of the strips obtained from polylactic acid. Copyright © 2013 Elsevier Ltd. All rights reserved.

Application of melt extrusion in the development of a physically and chemically stable high-energy amorphous solid dispersion of a poorly water-soluble drug.

PubMed

Lakshman, Jay P; Cao, Yu; Kowalski, James; Serajuddin, Abu T M

2008-01-01

Formulation of active pharmaceutical ingredients (API) in high-energy amorphous forms is a common strategy to enhance solubility, dissolution rate and, consequently, oral bioavailability of poorly water-soluble drugs. Amorphous APIs are, however, susceptible to recrystallization and, therefore, there is a need to physically stabilize them as solid dispersions in polymeric carriers. Hot melt extrusion has in recent years gained wide acceptance as a method of choice for the preparation of solid dispersions. There is a potential that the API, the polymer or both may degrade if excessively high temperature is needed in the melt extrusion process, especially when the melting point of the API is high. This report details a novel method where the API was first converted to an amorphous form by solvent evaporation and then melt-extruded with a suitable polymer at a drug load of at least 20% w/w. By this means, melt extrusion could be performed much below the melting temperature of the drug substance. Since the glass transition temperature of the amorphous drug was lower than that of the polymer used, the drug substance itself served as the plasticizer for the polymer. The addition of surfactants in the matrix enhanced dispersion and subsequent dissolution of the drug in aqueous media. The amorphous melt extrusion formulations showed higher bioavailability than formulations containing the crystalline API. There was no conversion of amorphous solid to its crystalline form during accelerated stability testing of dosage forms.

Effect of processing on phenolic antioxidants of fruits, vegetables, and grains--a review.

PubMed

Nayak, Balunkeswar; Liu, Rui Hai; Tang, Juming

2015-01-01

Understanding the influence of processing operations such as drying/dehydration, canning, extrusion, high hydrostatic pressure, pulsed electric field, and ohmic heating on the phytochemicals of fruits, vegetables, and grains is important in retaining the health benefiting properties of these antioxidative compounds in processed food products. Most of the previous investigations in the literature on the antioxidants of fruits, vegetables, and grains have shown that food-processing operations reduced the antioxidants of the processed foods, which is also the usual consumer perception. However, in the last decade some articles in the literature reported that the evaluation of nutritional quality of processed fruits and vegetables not only depend on the quantity of vitamin C but should include analyses of other antioxidant phytochemicals and antioxidant activity. Thermal processing increased the total antioxidant activity of tomato and sweet corn. Most importantly, analysis also depends on the condition, type, and mechanism of antioxidant assays used. This review aims to provide concise information on the influence of various thermal and nonthermal food-processing operations on the stability and kinetics of health beneficial phenolic antioxidants of fruits, vegetables, and grains.

Turbine airfoil fabricated from tapered extrusions

DOEpatents

Marra, John J

2013-07-16

An airfoil (30) and fabrication process for turbine blades with cooling channels (26). Tapered tubes (32A-32D) are bonded together in a parallel sequence, forming a leading edge (21), a trailing edge (22), and pressure and suction side walls (23, 24) connected by internal ribs (25). The tapered tubes may be extruded without camber to simplify the extrusion process, then bonded along matching surfaces (34), forming a non-cambered airfoil (28), which may be cambered in a hot forming process and cut (48) to length. The tubes may have tapered walls that are thinner at the blade tip (T1) than at the base (T2), reducing mass. A cap (50) may be attached to the blade tip. A mounting lug (58) may be forged (60) on the airfoil base and then machined, completing the blade for mounting in a turbine rotor disk.

A sustainable solid state recycling of pure aluminum by means of friction stir extrusion process (FSE)

NASA Astrophysics Data System (ADS)

Mehtedi, Mohamad El; Forcellese, Archimede; Simoncini, Michela; Spigarelli, Stefano

2018-05-01

In this research, the feasibility of solid-state recycling of pure aluminum AA1099 machining chips using FSE process is investigated. In the early stage, a FE simulation was conducted in order to optimize the die design and the process parameters in terms of plunge rotational speed and extrusion rate. The AA1099 aluminum chips were produced by turning of an as-received bar without lubrication. The chips were compacted on a MTS machine up to 150KN of load. The extruded samples were analyzed by optical and electron microscope in order to see the material flow and to characterize the microstructure. Finally, micro-hardness Vickers profiles were carried out, in both longitudinal and transversal direction of the obtained profiles, in order to investigate the homogeneity of the mechanical properties of the extrudate.

Numerical studies of the polymer melt flow in the extruder screw channel and the forming tool

NASA Astrophysics Data System (ADS)

Ershov, S. V.; Trufanova, N. M.

2017-06-01

To date, polymer compositions based on polyethylene or PVC is widely used as insulating materials. These materials processing conjugate with a number of problems during selection of the rational extrusion regimes. To minimize the time and cost when determining the technological regime uses mathematical modeling techniques. The paper discusses heat and mass transfer processes in the extruder screw channel, output adapter and the cable head. During the study were determined coefficients for three rheological models based on obtained viscosity vs. shear rate experimental data. Also a comparative analysis of this viscosimetric laws application possibility for studying polymer melt flow during its processing on the extrusion equipment was held. As a result of numerical study the temperature, viscosity and shear rate fields in the extruder screw channel and forming tool were obtained.

Ultrastructure of extrusomes in hypotrichous ciliate Pseudourostyla nova

NASA Astrophysics Data System (ADS)

Zhou, Yao; Wang, Zhengjun; Zhang, Jun; Gu, Fukang

2011-01-01

The ultrastructure of extrusomes of the hypotrichous ciliate Pseudourostyla nova was observed in scanning and transmission electron microscopy and enzyme-cytochemistry. The results show that the distribution, morphological characteristics, morphogenesis process, and extrusive process of the extrusomes in P. nova are different from the trichocysts in Paramecium, suggesting that the extrusomes of P. nova can respond to environmental stimuli, play an important role in the defense of this species, and cannot be regarded as "trichocysts". The results also suggest that the extrusomes might be originated from the Golgi apparatus and mature in the cytoplasm; after the extrusion of mature extrusomes, the residual substance might be reabsorbed and reused by the ciliate cell via food vacuoles, and take part in material recycling of the cell.

Method of Determining the Filtration Properties of oil-Bearing Crops in the Process of Their Pressing by the Example of Rape-oil Extrusion

NASA Astrophysics Data System (ADS)

Slavnov, E. V.; Petrov, I. A.

2014-07-01

A method of determining the change in the fi ltration properties of oil-bearing crops in the process of their pressing by repeated dynamic loading is proposed. The use of this method is demonstrated by the example of rape-oil extrusion. It was established that the change in the mass concentration of the oil in a rape mix from 0.45 to 0.23 leads to a decrease in the permeability of the mix by 101.5-102 times depending on the pressure applied to it. It is shown that the dependence of the permeability of this mix on the pressure applied to it is nonmonotone in character.

Rapidly progressive internal root resorption: a case report.

PubMed

Keinan, David; Heling, Ilana; Stabholtz, Adam; Moshonov, Joshua

2008-10-01

The etiology of internal root resorption is not fully understandable, trauma and chronic pulpitis are considered the main risk factors. Usually the process is asymptomatic and diagnosed upon routine radiographic examination. This case report presents a rapid progression of internal resorption related directly to traumatic injury. A 16-year-old female arrived at the emergency room after a mild extrusion of the mandibular incisors. The initial treatment included repositioning and splinting of the teeth. Radiographs performed at repositioning and splinting demonstrated normal configuration of the incisor's roots. Ten months later progressive internal resorption of the left mandibular first incisor was diagnosed. While treating this tooth similar process was detected in the right mandibular second incisor and in the mandibular left second incisor. The lower right first incisor reacted inconsistently to vitality test. As a result of the severe and rapidly progressive nature of the process, root canal treatments were performed in all lower incisors. The follow-up radiographs demonstrate arrest of the internal resorption process.

Water-mediated interactions enable smooth substrate transport in a bacterial efflux pump.

PubMed

Vargiu, Attilio Vittorio; Ramaswamy, Venkata Krishnan; Malvacio, Ivana; Malloci, Giuliano; Kleinekathöfer, Ulrich; Ruggerone, Paolo

2018-04-01

Efflux pumps of the Resistance-Nodulation-cell Division superfamily confer multi-drug resistance to Gram-negative bacteria. The most-studied polyspecific transporter belonging to this class is the inner-membrane trimeric antiporter AcrB of Escherichia coli. In previous studies, a functional rotation mechanism was proposed for its functioning, according to which the three monomers undergo concerted conformational changes facilitating the extrusion of substrates. However, the molecular determinants and the energetics of this mechanism still remain unknown, so its feasibility must be proven mechanistically. A computational protocol able to mimic the functional rotation mechanism in AcrB was developed. By using multi-bias molecular dynamics simulations we characterized the translocation of the substrate doxorubicin driven by conformational changes of the protein. In addition, we estimated for the first time the free energy profile associated to this process. We provided a molecular view of the process in agreement with experimental data. Moreover, we showed that the conformational changes occurring in AcrB enable the formation of a layer of structured waters on the internal surface of the transport channel. This water layer, in turn, allows for a fairly constant hydration of the substrate, facilitating its diffusion over a smooth free energy profile. Our findings reveal a new molecular mechanism of polyspecific transport whereby water contributes by screening potentially strong substrate-protein interactions. We provided a mechanistic understanding of a fundamental process related to multi-drug transport. Our results can help rationalizing the behavior of other polyspecific transporters and designing compounds avoiding extrusion or inhibitors of efflux pumps. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

Physicomechanical characterization of the extrusion-spheronization process. I. Instrumentation of the extruder.

PubMed

Shah, R D; Kabadi, M; Pope, D G; Augsburger, L L

1994-03-01

Extrusion-spheronization is a popular means of producing spheres which can be coated to form a controlled-release system. In the extrusion process, stress is necessary to force a wet mass through small orifices, and as a result, frictional heat builds up at the screen. Therefore, the quantitative measurement of the screen pressure and screen temperature is described and shown to provide objective measures of extrudability. A strain gauge load cell was mounted tangentially to the screen of a Luwa EXDS-60 extruder with a specifically fabricated holder. The load cell output was calibrated in terms of pressure inside the screen with a special rubber plug system. A fast-response thermocouple was used to measure the screen temperature. Experiments with 50/50 lactose/Avicel PH101 revealed that a linear relationship exists between the amount of water used in the granulation and the screen pressure, that the percentage open area of the screen determines the rank order of the screen pressure, and that the maximal yield of 18/25-mesh cut pellets was uniquely related to the screen pressure. Also, a high degree of correlation was observed between the screen pressure and the screen temperature.

Conservation of extrusion as an exit mechanism for Chlamydia.

PubMed

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. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

PubMed

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.

Deformational Features and Microstructure Evolution of Copper Fabricated by a Single Pass of the Elliptical Cross-Section Spiral Equal-Channel Extrusion (ECSEE) Process

NASA Astrophysics Data System (ADS)

Wang, Chengpeng; Li, Fuguo; Liu, Juncheng

2018-04-01

The objectives of this work are to study the deformational feature, textures, microstructures, and dislocation configurations of ultrafine-grained copper processed by the process of elliptical cross-section spiral equal-channel extrusion (ECSEE). The deformation patterns of simple shear and pure shear in the ECSEE process were evaluated with the analytical method of geometric strain. The influence of the main technical parameters of ECSEE die on the effective strain distribution on the surface of ECSEE-fabricated samples was examined by the finite element simulation. The high friction factor could improve the effective strain accumulation of material deformation. Moreover, the pure copper sample fabricated by ECSEE ion shows a strong rotated cube shear texture. The refining mechanism of the dislocation deformation is dominant in copper processed by a single pass of ECSEE. The inhomogeneity of the micro-hardness distribution on the longitudinal section of the ECSEE-fabricated sample is consistent with the strain and microstructure distribution features.

Hydrophilic thermoplastic polyurethanes for the manufacturing of highly dosed oral sustained release matrices via hot melt extrusion and injection molding.

PubMed

Verstraete, G; Van Renterghem, J; Van Bockstal, P J; Kasmi, S; De Geest, B G; De Beer, T; Remon, J P; Vervaet, C

2016-06-15

Hydrophilic aliphatic thermoplastic polyurethane (Tecophilic™ grades) matrices for high drug loaded oral sustained release dosage forms were formulated via hot melt extrusion/injection molding (HME/IM). Drugs with different aqueous solubility (diprophylline, theophylline and acetaminophen) were processed and their influence on the release kinetics was investigated. Moreover, the effect of Tecophilic™ grade, HME/IM process temperature, extrusion speed, drug load, injection pressure and post-injection pressure on in vitro release kinetics was evaluated for all model drugs. (1)H NMR spectroscopy indicated that all grades have different soft segment/hard segment ratios, allowing different water uptake capacities and thus different release kinetics. Processing temperature of the different Tecophilic™ grades was successfully predicted by using SEC and rheology. Tecophilic™ grades SP60D60, SP93A100 and TG2000 had a lower processing temperature than other grades and were further evaluated for the production of IM tablets. During HME/IM drug loads up to 70% (w/w) were achieved. In addition, Raman mapping and (M)DSC results confirmed the homogenous distribution of mainly crystalline API in all polymer matrices. Besides, hydrophilic TPU based formulations allowed complete and sustained release kinetics without using release modifiers. As release kinetics were mainly affected by drug load and the length of the PEO soft segment, this polymer platform offers a versatile formulation strategy to adjust the release rate of drugs with different aqueous solubility. Copyright © 2016 Elsevier B.V. All rights reserved.

75 FR 80527 - Aluminum Extrusions From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-22

...)] Aluminum Extrusions From China AGENCY: United States International Trade Commission. ACTION: Scheduling of... of subsidized and less-than-fair-value imports from China of aluminum extrusions, primarily provided... contained in Aluminum Extrusions From the People's Republic of China: Notice of Preliminary Determination of...

Numerical studies of temperature effect on the extrusion fracture and swell of plastic micro-pipe

NASA Astrophysics Data System (ADS)

Ren, Zhong; Huang, Xingyuan; Xiong, Zhihua

2018-03-01

Temperature is a key factor that impacts extrusion forming quality of plastic micro-pipe. In this study, the effect of temperature on extrusion fracture and swell of plastic micro-pipe was investigated by numerical method. Under a certain of the melt’s flow volume, the extrusion pattern, extrusion swelling ratio of melt are obtained under different temperatures. Results show that the extrusion swelling ratio of plastic micro-pipe decreases with increasing of temperature. In order to study the reason of temperature effect, the physical distributions of plastic micro-pipe are gotten. Numerical results show that the viscosity, pressure, stress value of melt are all decreased with the increasing of temperature, which leads to decrease the extrusion swell and fracture phenomenon for the plastic micro-pipe.

[Effect of the sorghum extraction process on the color of the flour and tortillas made from mixtures with lime-treated cornmeal].

PubMed

Martínez, F; Ciacco, C F; Salinas, Y

1992-06-01

The objective of this work was to study the effect of the extrusion process in the color of instant flours and its tortillas prepared with mixtures of commercial instant corn flour. In the extrusion process four flours from two genotypes of sorghum (whole and decorticated sorghum of each genotype) were used. These flours were processed in a single screw Brabender laboratory extruder. In the preparation of sorghum tortillas and sorghum-corn tortillas four flours were selected from the extrusion process. 1) genotype CMSXS 9A: Whole flour extruded with moisture content of 15% and screw rate of 130 rpm, flour from decorticated sorghum with particle size less than 0.420 mm extruded with moisture content of 15% and screw rate of 130 rpm, 2) genotype CMSXS 145: whole flour extruded with moisture content of 18% and screw rate of 170 rpm, decorticated sorghum flour extruded with moisture content of 15% and screw rate of 130 rpm. Also these flours were utilized with mixtures of commercial instant cornflour for the preparation of tortillas. The instant sorghum flours and tortillas from decorticated sorghum (20% = presented whiter color compared to instant whole sorghum flour and its tortillas. The addition of different levels of commercial instant corn flour (10, 20, 30, 40 and 50%) to the instant sorghum flours improved the color of the mixtures of flour and tortillas. This improvement was more pronounced with instant sorghum flour from whole sorghum grain.(ABSTRACT TRUNCATED AT 250 WORDS)

Physicochemical properties of film-coated melt-extruded pellets.

PubMed

Young, Chistopher R; Crowley, Michael; Dietzsch, Caroline; McGinity, James W

2007-02-01

The purpose of this study was to investigate the physicochemical properties of poly(ethylene oxide) (PEO) and guaifenesin containing beads prepared by a melt-extrusion process and film-coated with a methacrylic acid copolymer. Solubility parameter calculations, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), modulated differential scanning calorimetry (MDSC), X-ray powder diffraction (XRPD) and high performance liquid chromatography (HPLC) were used to determine drug/polymer miscibility and/or the thermal processibility of the systems. Powder blends of guaifenesin, PEO and functional excipients were processed using a melt-extrusion and spheronization technique and then film-coated in a fluidized bed apparatus. Solubility parameter calculations were used to predict miscibility between PEO and guaifenesin, and miscibility was confirmed by SEM and observation of a single melting point for extruded drug/polymer blends during MDSC investigations. The drug was stable following melt-extrusion as determined by TGA and HPLC; however, drug release rate from pellets decreased upon storage in sealed HDPE containers with silica desiccants at 40 degrees C/75% RH. The weight loss on drying, porosity and tortuosity determinations were not influenced by storage. Recrystallization of guaifenesin and PEO was confirmed by SEM and XRPD. Additionally, the pellets exhibited a change in adhesion behaviour during dissolution testing. The addition of ethylcellulose to the extruded powder blend decreased and stabilized the drug release rate from the thermally processed pellets. The current study also demonstrated film-coating to be an efficient process for providing melt-extruded beads with pH-dependent drug release properties that were stable upon storage at accelerated conditions.

Influence of pressurized carbon dioxide on ketoprofen-incorporated hot-melt extruded low molecular weight hydroxypropylcellulose.

PubMed

A Ashour, Eman; Kulkarni, Vijay; Almutairy, Bjad; Park, Jun-Bom; Shah, Sejal P; Majumdar, Soumyajit; Lian, Zhuoyang; Pinto, Elanor; Bi, Vivian; Durig, Thomas; Martin, Scott T; Repka, Michael A

2016-01-01

The aim of the current research project was to investigate the effect of pressurized carbon dioxide (P-CO 2 ) on the physico-mechanical properties of ketoprofen (KTP)-incorporated hydroxypropylcellulose (HPC) (Klucel™ ELF, EF, and LF) produced using hot-melt extrusion (HME) techniques and to assess the plasticization effect of P-CO 2 on the various polymers tested. The physico-mechanical properties of extrudates with and without injection of P-CO 2 were examined and compared with extrudates with the addition of 5% liquid plasticizer of propylene glycol (PG). The extrudates were milled and compressed into tablets. Tablet characteristics of the extrudates with and without injection of P-CO 2 were evaluated. P-CO 2 acted as a plasticizer for tested polymers, which allowed for the reduction in extrusion processing temperature. The microscopic morphology of the extrudates was changed to a foam-like structure due to the expansion of the CO 2 at the extrusion die. The foamy extrudates demonstrated enhanced KTP release compared with the extrudates processed without P-CO 2 due to the increase of porosity and surface area of those extrudates. Furthermore, the hardness of the tablets prepared by foamy extrudates was increased and the percent friability was decreased. Thus, the good binding properties and compressibility of the extrudates were positively influenced by utilizing P-CO 2 processing.

Influence of Pressurized Carbon Dioxide on Ketoprofen-Incorporated Hot-Melt Extruded Low Molecular Weight Hydroxypropylcellulose

PubMed Central

Ashour, Eman A.; Kulkarni, Vijay; Almutairy, Bjad; Park, Jun-Bom; Shah, Sejal; Majumdar, Soumyajit; Lian, Zhuoyang; Pinto, Elanor; Bi, Yunxia; Durig, Thomas; Martin, Scott T.; Repka, Michael A.

2017-01-01

Objectives The aim of the current research project was to investigate the effect of pressurized carbon dioxide (P-CO2) on the physico-mechanical properties of Ketoprofen (KTP)-incorporated hydroxypropylcellulose (HPC) (Klucel™ ELF, EF and LF) produced using hot melt extrusion (HME) techniques and to assess the plasticization effect of P-CO2 on the various polymers tested. Methods The physico-mechanical properties of extrudates with and without injection of P-CO2 were examined and compared to extrudates with the addition of 5% liquid plasticizer of propylene glycol (PG). The extrudates were milled and compressed into tablets. Tablet characteristics of the extrudates with and without injection of P-CO2 were evaluated. Results & conclusion P-CO2 acted as a plasticizer for tested polymers, which allowed for the reduction in extrusion processing temperature. The microscopic morphology of the extrudates were changed to a foam-like structure due to expansion of the CO2 at the extrusion die. The foamy extrudates demonstrated enhanced KTP release compared to the extrudates processed without P-CO2 due to the increase of porosity and surface area of those extrudates. Furthermore, the hardness of the tablets prepared by foamy extrudates was increased and the percent friability was decreased. Thus, the good binding properties and compressibility of the extrudates were positively influenced by utilizing P-CO2 processing. PMID:25997363

Design and fabrication of conductive polyaniline transducers via computer controlled direct ink writing

NASA Astrophysics Data System (ADS)

Holness, F. Benjamin; Price, Aaron D.

2017-04-01

The intractable nature of the conjugated polymer (CP) polyaniline (PANI) has largely limited PANI-based transducers to monolithic geometries derived from thin-film deposition techniques. To address this limitation, we have previously reported additive manufacturing processes for the direct ink writing of three-dimensional electroactive PANI structures. This technology incorporates a modified delta robot having an integrated polymer paste extrusion system in conjunction with a counter-ion induced thermal doping process to achieve these 3D structures. In this study, we employ an improved embodiment of this methodology for the fabrication of functional PANI devices with increasingly complex geometries and enhanced electroactive functionality. Advances in manufacturing capabilities achieved through the integration of a precision pneumatic fluid dispenser and redesigned high-pressure end-effector enable extrusion of viscous polymer formulations, improving the realizable resolutions of features and deposition layers. The integration of a multi-material dual-extrusion end-effector has further aided the fabrication of these devices, enabling the concurrent assembly of passive and active structures, which reduces the limitations on device geometry. Subsequent characterization of these devices elucidates the relationships between polymer formulation, process parameters, and device design such that electromechanical properties can be tuned according to application requirements. This methodology ultimately leads to the improved manufacturing of electroactive polymer-enabled devices with high-resolution 3D features and enhanced electroactive performance.

An Extrusion Spheronization Approach to Enable a High Drug Load Formulation of a Poorly Soluble Drug with a Low Melting Surfactant.

PubMed

Tatavarti, Aditya; Kesisoglou, Filippos

2015-11-01

Vitamin E tocopherol polyethylene glycol succinate (TPGS) is a non-ionic surface active agent, known to enhance the bioavailability of lipophilic compounds via wettability, solubility, and in some cases permeability enhancement. MK-0536 is an anti-retroviral drug with poor wettability and solubility and a high dose. Based on pharmacokinetic studies in dogs and humans, use of vitamin E TPGS in oral solid formulations of MK-0536 provides desired PK characteristics. The use of vitamin E TPGS, however, in solid dosage forms is limited because of the processing challenges resulting from its waxy nature and low melting temperature (∼37°C). The current study, for the first time, demonstrates the use of an alternative low pressure extrusion and spheronization approach to enable high loadings of the poorly soluble, poorly compactable drug and relatively high levels of vitamin E TPGS. This approach not only aided in mitigating processing challenges arising from most high energy process steps such as milling, compression, and coating, but also enabled a higher drug load formulation that provided superior bioperformance relative to a conventional high shear wet granulated formulation. An encapsulated dosage form consisting of pellets prepared by extrusion spheronization with 75% (w/w) MK-0536 and 10% (w/w) vitamin E TPGS was developed. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Integration of Basic Knowledge Models for the Simulation of Cereal Foods Processing and Properties.

PubMed

Kristiawan, Magdalena; Kansou, Kamal; Valle, Guy Della

Cereal processing (breadmaking, extrusion, pasting, etc.) covers a range of mechanisms that, despite their diversity, can be often reduced to a succession of two core phenomena: (1) the transition from a divided solid medium (the flour) to a continuous one through hydration, mechanical, biochemical, and thermal actions and (2) the expansion of a continuous matrix toward a porous structure as a result of the growth of bubble nuclei either by yeast fermentation or by water vaporization after a sudden pressure drop. Modeling them is critical for the domain, but can be quite challenging to address with mechanistic approaches relying on partial differential equations. In this chapter we present alternative approaches through basic knowledge models (BKM) that integrate scientific and expert knowledge, and possess operational interest for domain specialists. Using these BKMs, simulations of two cereal foods processes, extrusion and breadmaking, are provided by focusing on the two core phenomena. To support the use by non-specialists, these BKMs are implemented as computer tools, a Knowledge-Based System developed for the modeling of the flour mixing operation or Ludovic ® , a simulation software for twin screw extrusion. They can be applied to a wide domain of compositions, provided that the data on product rheological properties are available. Finally, it is stated that the use of such systems can help food engineers to design cereal food products and predict their texture properties.

Manufacture of Regularly Shaped Sol-Gel Pellets

NASA Technical Reports Server (NTRS)

Leventis, Nicholas; Johnston, James C.; Kinder, James D.

2006-01-01

An extrusion batch process for manufacturing regularly shaped sol-gel pellets has been devised as an improved alternative to a spray process that yields irregularly shaped pellets. The aspect ratio of regularly shaped pellets can be controlled more easily, while regularly shaped pellets pack more efficiently. In the extrusion process, a wet gel is pushed out of a mold and chopped repetitively into short, cylindrical pieces as it emerges from the mold. The pieces are collected and can be either (1) dried at ambient pressure to xerogel, (2) solvent exchanged and dried under ambient pressure to ambigels, or (3) supercritically dried to aerogel. Advantageously, the extruded pellets can be dropped directly in a cross-linking bath, where they develop a conformal polymer coating around the skeletal framework of the wet gel via reaction with the cross linker. These pellets can be dried to mechanically robust X-Aerogel.

The Effect of Emulsion Intensity on Selected Sensory and Instrumental Texture Properties of Full-Fat Mayonnaise

PubMed Central

Olsson, Viktoria; Håkansson, Andreas

2018-01-01

Varying processing conditions can strongly affect the microstructure of mayonnaise, opening up new applications for the creation of products tailored to meet different consumer preferences. The aim of the study was to evaluate the effect of emulsification intensity on sensory and instrumental characteristics of full-fat mayonnaise. Mayonnaise, based on a standard recipe, was processed at low and high emulsification intensities, with selected sensory and instrumental properties then evaluated using an analytical panel and a back extrusion method. The evaluation also included a commercial reference mayonnaise. The overall effects of a higher emulsification intensity on the sensory and instrumental characteristics of full-fat mayonnaise were limited. However, texture was affected, with a more intense emulsification resulting in a firmer mayonnaise according to both back extrusion data and the analytical sensory panel. Appearance, taste and flavor attributes were not affected by processing. PMID:29342128

Does apical negative pressure prevent the apical extrusion of debris and irrigant compared with conventional irrigation? A systematic review and meta-analysis.

PubMed

Romualdo, Priscilla Coutinho; de Oliveira, Katharina Morant Holanda; Nemezio, Mariana Alencar; Küchler, Erika Calvano; Silva, Raquel Assed Bezerra; Nelson-Filho, Paulo; Silva, Lea Assed Bezerra

2017-12-01

The aim of this study was to evaluate if apical negative pressure (ANP) irrigation prevents the apical extrusion of debris and irrigant compared with conventional needle irrigation through a systematic review and meta-analysis. A computer search of dental literature was performed using four different databases. A combination of the terms 'apical negative pressure', 'endovac', 'apical extrusion', 'extrusion' and 'endodontics' was used. Studies that used extracted human teeth with a mature apex and that evaluated the apical extrusion of debris and/or irrigating solution were included. After an evaluation of the full studies according to the eligibility criteria, eight studies were critically analysed and subjected to quality assessment and risk of bias. Only four studies that evaluated extrusion of irrigant were considered as having high methodological quality and were subjected to a meta-analysis. Studies evaluating extrusion of debris did not have sufficient methodological quality to be subjected to the meta-analysis. The forest plot indicated that ANP irrigation prevents the risk of irrigant extrusion compared with conventional irrigation (OR 0.07 [95%CI 0.02-0.20]; P < 0.00001). This systematic review and meta-analysis showed that ANP prevents the apical extrusion of irrigant. There is no evidence if this type of irrigation prevents the extrusion of debris. © 2017 Australian Society of Endodontology Inc.

Laboratory experiments from the toy store

NASA Technical Reports Server (NTRS)

Mcclelland, H. T.

1992-01-01

The following is a laboratory experiment designed to further understanding of materials science. This material could be taught to a typical student of materials science or manufacturing at the high school level or above. The objectives of this experiment are as follows: (1) to qualitatively demonstrate the concepts of elasticity, plasticity, and the strain rate and temperature dependence of the mechanical properties of engineering materials; (2) to qualitatively demonstrate the basics of extrusion including material flow, strain rate dependence of defects, lubrication effects, and the making of hollow shapes by extrusion (the two parts may be two separate experiments done at different times when the respective subjects are covered); and (3) to demonstrate the importance of qualitative observations and the amount of information which can be gathered without quantitative measurements.

Co-extrusion as a processing technique to manufacture a dual sustained release fixed-dose combination product.

PubMed

Vynckier, An-Katrien; Voorspoels, Jody; Remon, Jean Paul; Vervaet, Chris

2016-05-01

This study aimed to design a fixed-dose combination dosage form which provides a sustained release profile for both the freely water-soluble metformin HCl and the poorly soluble gliclazide, two antidiabetic compounds used to treat diabetes mellitus. Hot-melt co-extrusion was used as an innovative manufacturing technique for a pharmaceutical fixed-dose combination product. In this way, a matrix formulation that sustained metformin release could be developed, despite the high drug load in the formulation and the freely soluble nature of the drug. It was clear that co-extrusion was perfectly suited to produce a fixed-dose combination product with adequate properties for each of the incorporated APIs. A coat layer, containing at least 30% CAPA(®) 6506 as a hydrophobic polymer, was necessary to adequately sustain the release of the highly dosed freely soluble drug from the 70% metformin HCl-loaded CAPA(®) 6506 core of the co-extrudate. To obtain a complete gliclazide release over 24-h solubilization in Kollidon(®) VA, added as a second polymer to the CAPA(®) 6506 in the coat, was needed. Both active pharmaceutical ingredients (APIs), which have different physicochemical characteristics, were formulated in a single dosage form, using co-extrusion. © 2016 Royal Pharmaceutical Society, Journal of Pharmacy and Pharmacology.

A Miniaturized Extruder to Prototype Amorphous Solid Dispersions: Selection of Plasticizers for Hot Melt Extrusion.

PubMed

Lauer, Matthias E; Maurer, Reto; Paepe, Anne T De; Stillhart, Cordula; Jacob, Laurence; James, Rajesh; Kojima, Yuki; Rietmann, Rene; Kissling, Tom; van den Ende, Joost A; Schwarz, Sabine; Grassmann, Olaf; Page, Susanne

2018-05-19

Hot-melt extrusion is an option to fabricate amorphous solid dispersions and to enhance oral bioavailability of poorly soluble compounds. The selection of suitable polymer carriers and processing aids determines the dissolution, homogeneity and stability performance of this solid dosage form. A miniaturized extrusion device (MinEx) was developed and Hypromellose acetate succinate type L (HPMCAS-L) based extrudates containing the model drugs neurokinin-1 (NK1) and cholesterylester transfer protein (CETP) were manufactured, plasticizers were added and their impact on dissolution and solid-state properties were assessed. Similar mixtures were manufactured with a lab-scale extruder, for face to face comparison. The properties of MinEx extrudates widely translated to those manufactured with a lab-scale extruder. Plasticizers, Polyethyleneglycol 4000 (PEG4000) and Poloxamer 188, were homogenously distributed but decreased the storage stability of the extrudates. Stearic acid was found condensed in ultrathin nanoplatelets which did not impact the storage stability of the system. Depending on their distribution and physicochemical properties, plasticizers can modulate storage stability and dissolution performance of extrudates. MinEx is a valuable prototyping-screening method and enables rational selection of plasticizers in a time and material sparing manner. In eight out of eight cases the properties of the extrudates translated to products manufactured in lab-scale extrusion trials.

The numerical simulation and experiment on extrusion roller embossing of light diffusion plate with micro-structure

NASA Astrophysics Data System (ADS)

Zang, Gongzheng; Fu, Zhihong; Zhang, Lei; Wan, Yue

2018-01-01

Extrusion roller embossing process has demonstrated the ability to produce polymer film with micro-structure. However the influence of various parameters on the forming quality has not been understood clearly. In this paper, a light diffusion plate with semi cylindrical micro-structure array as the research object, the influence of the main processing parameters such as roller speed, pressuring distance and polymer film temperature to the rolling quality was investigated in detail by simulation and experimental methods. The results show that the thickness of the light diffusion plate and the micro-structure fitting diameter increases with the increasing of the roll speed and the polymer film temperature, and decreases with the increasing of the pressing distance. Besides, the simulation results conformed well to the experimental results.

The preparation by extrusion/spheronization and the properties of pellets containing drugs, microcrystalline cellulose and glyceryl monostearate.

PubMed

Chatchawalsaisin, Jittima; Podczeck, Fridrun; Newton, J Michael

2005-01-01

Pellets have been prepared by extrusion and spheronization containing microcrystalline cellulose (MCC) and four model drugs with decreasing order of solubility, paracetamol (P), diclofenac sodium (D), ibuprofen (IB) and indomethacin (IN) at a 10% level with and without the addition of a range of levels of glyceryl monostearate (GMS). The drugs differed in their response to extrusion in that all formulations containing the drug D had a 'steady state' extrusion profile whereas the other three drugs exhibited 'forced flow' indicating the possibility of water migration during the process of ram extrusion. The presence of GMS did not influence this effect. The drug D also required consistently less water to function than the other three drugs. In spite of these differences in extrusion performance, it was possible to prepare satisfactory pellets from formulations of all the drugs with 0, 30 and 60% GMS combined with 90, 60 or 30% of MCC at a range of water levels. It was also possible to prepare pellets containing the drug D with 70, 80 and 90% GMS, with corresponding quantities of 20, 10 and 0% of MCC. It was also possible to prepare the pellet formulations by dispersing the drugs in molten GMS, grinding and processing this with MCC and water. Such systems retained the processing characteristics of the composition made by the blending of the powder. The presence of GMS in all cases reduced the quantity of water required for the process to function. The steady state or the mean of the range of the forces observed during forced flow, were dependent on the composition and the quantity of water added. The surface of the extrudate appeared smooth and measurements of surface roughness established that the value of the rugosity R(a) for any of the extrudates did not exceed 6 microm. The extrudate diameter was found to increase with the quantity of GMS in the formulation. The pellets produced were all within a relatively narrow size range (three sieve fractions of a root two progression), the median value of which increased with the level of GMS. For the drug D, there was a linear increase of pellet diameter with increase in the extrudate diameter. For the three other drugs this relationship was less certain but nevertheless there was a similar trend for the pellet diameter to increase as the extrudate diameter increased, suggesting the mechanism of the process is the same irrespective of the composition. Considering the value of the shape factor e(R), all the pellets produced from the various formulations were well within acceptable levels for further processing and the only observable trend in the values was that the formulations with the lower water contents were the least round. The porosity of the pellets of the different formulations generally decreased with the increase in water used to prepare the pellets, the extent of this decrease being dependent on the drug and the level of GMS. The in vitro drug release from the pellets was controlled by the solubility of the drug, the lower the value of the solubility, the longer the mean dissolution time (MDT). This was not influenced by the presence of GMS or the method of incorporation of the drug into the formulation.

Micromechanics f an Extrusion in High-Cycle Fatigue With Creep

DTIC Science & Technology

1988-01-01

amount referred to as the "static extrusion" ( Mughrabi et al , 1983). This E{a causes an initial compression ta, in R. As the extrusion grows under cyclic...Deformation of sin- gle crystals at elevated temperatures (Johnson, et al , 1953, 1955) also occurs by slip in pri- marily the same slip systems that...growth will cease after the extrusion has reached the static extrusion. Lin, et al ., 1988 have shown that the residual tensile stress ’tact caused by

Alkaline twin-screw extrusion pretreatment for fermentable sugar production

PubMed Central

2013-01-01

Background The inevitable depletion of fossil fuels has resulted in an increasing worldwide interest in exploring alternative and sustainable energy sources. Lignocellulose, which is the most abundant biomass on earth, is widely regarded as a promising raw material to produce fuel ethanol. Pretreatment is an essential step to disrupt the recalcitrance of lignocellulosic matrix for enzymatic saccharification and bioethanol production. This paper established an ATSE (alkaline twin-screw extrusion pretreatment) process using a specially designed twin-screw extruder in the presence of alkaline solution to improve the enzymatic hydrolysis efficiency of corn stover for the production of fermentable sugars. Results The ATSE pretreatment was conducted with a biomass/liquid ratio of 1/2 (w/w) at a temperature of 99°C without heating equipment. The results indicated that ATSE pretreatment is effective in improving the enzymatic digestibility of corn stover. Sodium hydroxide loading is more influential factor affecting both sugar yield and lignin degradation than heat preservation time. After ATSE pretreatment under the proper conditions (NaOH loading of 0.06 g/g biomass during ATSE and 1 hour heat preservation after extrusion), 71% lignin removal was achieved and the conversions of glucan and xylan in the pretreated biomass can reach to 83% and 89% respectively via subsequent enzymatic hydrolysis (cellulase loading of 20 FPU/g-biomass and substrate consistency of 2%). About 78% of the original polysaccharides were converted into fermentable sugars. Conclusions With the physicochemical functions in extrusion, the ATSE method can effectively overcome the recalcitrance of lignocellulose for the production of fermentable sugars from corn stover. This process can be considered as a promising pretreatment method due to its relatively low temperature (99°C), high biomass/liquid ratio (1/2) and satisfied total sugar yield (78%), despite further study is needed for process optimization and cost reduction. PMID:23834726

Development and efficiency assessment of process lubrication for hot forging

NASA Astrophysics Data System (ADS)

Kargin, S.; Artyukh, Viktor; Ignatovich, I.; Dikareva, Varvara

2017-10-01

The article considers innovative technologies in testing and production of process lubricants for hot bulk forging. There were developed new compositions of eco-friendly water-graphite process lubricants for hot extrusion and forging. New approaches to efficiency assessment of process lubricants are developed and described in the following article. Laboratory and field results are presented.

Cell Extrusion: A Stress-Responsive Force for Good or Evil in Epithelial Homeostasis.

PubMed

Ohsawa, Shizue; Vaughen, John; Igaki, Tatsushi

2018-02-05

Epithelial tissues robustly respond to internal and external stressors via dynamic cellular rearrangements. Cell extrusion acts as a key regulator of epithelial homeostasis by removing apoptotic cells, orchestrating morphogenesis, and mediating competitive cellular battles during tumorigenesis. Here, we delineate the diverse functions of cell extrusion during development and disease. We emphasize the expanding role for apoptotic cell extrusion in exerting morphogenetic forces, as well as the strong intersection of cell extrusion with cell competition, a homeostatic mechanism that eliminates aberrant or unfit cells. While cell competition and extrusion can exert potent, tumor-suppressive effects, dysregulation of either critical homeostatic program can fuel cancer progression. Copyright © 2018 Elsevier Inc. All rights reserved.

Rapid prototype extruded conductive pathways

DOEpatents

Bobbitt, III, John T.

2016-06-21

A process of producing electrically conductive pathways within additively manufactured parts and similar parts made by plastic extrusion nozzles. The process allows for a three-dimensional part having both conductive and non-conductive portions and allows for such parts to be manufactured in a single production step.

Characterization of the microstructure of Nb-1wt.%Zr-0.1wt.%C tubes as affected by thermomechanical processing

NASA Technical Reports Server (NTRS)

Uz, Mehmet; Titran, Robert H.

1993-01-01

Microstructure of Nb-1Zr-0.1C tubes were characterized as affected by extrusion temperature of the tube shell and its thermomechanical processing to tubing. Two tube shells of about 40-mm outside diameter (OD) and 25-mm inside diameter (ID) were extruded 8:1 from a vacuum arc-melted ingot at 1900 and 1550 K. Two different OD tubes of approximately 0.36-mm wall thickness were fabricated from each tube shell by a series of 26 cold drawing operations with two in process anneals. The microstructure of tube shells and the tubing before and after a 2-step heat treatment were characterized. Residue extracted chemically from each sample was also analyzed to identify the precipitates. The results concerning the effect of the initial extrusion temperature and subsequent processing on the microstructure of the tubes are presented together with a review of results from similar work on Nb-1Zr-0.1C sheet stock.

75 FR 34982 - Aluminum Extrusions from the People's Republic of China: Notice of Postponement of Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-21

... DEPARTMENT OF COMMERCE International Trade Administration [C-570-968] Aluminum Extrusions from the... in the Federal Register a notice of initiation of the countervailing duty investigation of aluminum extrusions from the People's Republic of China. See Aluminum Extrusions From the People's Republic of China...

76 FR 80887 - Antidumping Order on Aluminum Extrusions from the People's Republic of China: Initiation of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-27

..., participated in the antidumping duty investigation of aluminum extrusions from the PRC. The Department issued its final determination for this investigation on April 4, 2011. See Aluminum Extrusions From the..., customers, suppliers, etc. Scope of the Order The merchandise covered by the order is aluminum extrusions...

Comparison of apical and coronal extrusions using reciprocating and rotary instrumentation systems.

PubMed

Lu, Yan; Chen, Min; Qiao, Feng; Wu, Ligeng

2015-08-07

The aim of this study was to compare the apical and coronal extrusions by using two reciprocating and two rotary instrumentation systems. Eighty extracted human single-rooted anterior teeth were randomly assigned to four groups. Four different root canal instrumentation systems were used according to the manufacturers instructions, including two reciprocating single-file systems, Reciproc and WaveOne, and two full-sequence rotary BLX and ProTaper instruments. Debris collected from the coronal by the instruments and apical extrusions were quantified respectively. After drying the collections, the mean weight of debris collected from apical and coronal extrusions was assessed using an electronic balance and analyzed using the Kruskal-Wallis H and Mann-Whitney U tests. Statistically significant differences in the apical extrusion were observed among the four groups. Reciproc and WaveOne instruments produced significantly less debris than BLX and ProTaper instruments (P < 0.05). All of the systems produced apical extrusion of debris. However, reciprocating single-file systems produced less apical extrusion than full-sequence rotary systems. No relationship was observed between apical and coronal extrusions.

Earthquake induced variations in extrusion rate: A numerical modeling approach to the 2006 eruption of Merapi Volcano (Indonesia)

NASA Astrophysics Data System (ADS)

Carr, Brett B.; Clarke, Amanda B.; de'Michieli Vitturi, Mattia

2018-01-01

Extrusion rates during lava dome-building eruptions are variable and eruption sequences at these volcanoes generally have multiple phases. Merapi Volcano, Java, Indonesia, exemplifies this common style of activity. Merapi is one of Indonesia's most active volcanoes and during the 20th and early 21st centuries effusive activity has been characterized by long periods of very slow (<0.1 m3 s-1) extrusion rate interrupted every few years by short episodes of elevated extrusion rates (1-4 m3 s-1) lasting weeks to months. One such event occurred in May-July 2006, and previous research has identified multiple phases with different extrusion rates and styles of activity. Using input values established in the literature, we apply a 1D, isothermal, steady-state numerical model of magma ascent in a volcanic conduit to explain the variations and gain insight into corresponding conduit processes. The peak phase of the 2006 eruption occurred in the two weeks following the May 27 Mw 6.4 earthquake 50 km to the south. Previous work has suggested that the peak extrusion rates observed in early June were triggered by the earthquake through either dynamic stress-induced overpressure or the addition of CO2 due to decarbonation and gas escape from new fractures in the bedrock. We use the numerical model to test the feasibility of these proposed hypotheses and show that, in order to explain the observed change in extrusion rate, an increase of approximately 5-7 MPa in magma storage zone overpressure is required. We also find that the addition of ∼1000 ppm CO2 to some portion of the magma in the storage zone following the earthquake reduces water solubility such that gas exsolution is sufficient to generate the required overpressure. Thus, the proposed mechanism of CO2 addition is a viable explanation for the peak phase of the Merapi 2006 eruption. A time-series of extrusion rate shows a sudden increase three days following the earthquake. We explain this three-day delay by the combined time required for the effects of the earthquake and corresponding CO2 increase to develop in the magma storage system (1-2 days), and the time we calculate for the affected magma to ascend from storage zone to surface (40 h). The increased extrusion rate was sustained for 2-7 days before dissipating and returning to pre-earthquake levels. During this phase, we estimate that 3.5 million m3 DRE of magma was erupted along with 11 ktons of CO2. The final phase of the 2006 eruption was characterized by highly variable extrusion rates. We demonstrate that those changes were likely controlled by failure of the edifice that had been confining the dome to Merapi's crater and subsequent large dome collapses. The corresponding reductions in confining pressure caused increased extrusion rates that rapidly rebuilt the dome and led to further collapses, a feedback cycle that prolonged the eruption. In a more general sense, this study demonstrates that both internal changes, such as magma volatile content and overpressure, and external forces, such as edifice collapse and regional earthquakes, can affect variations in eruption intensity. Further, we also demonstrate how these external forces can initiate internal changes and how these parameters may interact with one another in a feedback scenario.

Graft extrusion in both the coronal and sagittal planes is greater after medial compared with lateral meniscus allograft transplantation but is unrelated to early clinical outcomes.

PubMed

Lee, Dae-Hee; Lee, Chang-Rack; Jeon, Jin-Ho; Kim, Kyung-Ah; Bin, Seong-Il

2015-01-01

Graft extrusion after meniscus allograft transplantation (MAT) may be affected by horn fixation, which differs between medial and lateral MAT. Few studies have compared graft extrusion, especially sagittal extrusion, after medial and lateral MAT. In patients undergoing medial and lateral MAT, graft extrusion is likely similar and not correlated with postoperative Lysholm scores. Cohort study; Level of evidence, 2. Meniscus graft extrusion in the coronal and sagittal planes was compared in 51 knees undergoing medial MAT and 84 undergoing lateral MAT. Distances from the anterior and posterior articular cartilage margins to the anterior (anterior cartilage meniscus distance [ACMD]) and posterior (posterior cartilage meniscus distance [PCMD]) horns, respectively, were assessed on immediate postoperative magnetic resonance imaging and compared in patients undergoing medial and lateral MAT. Correlations between coronal and sagittal graft extrusion and between extrusion and the Lysholm score were compared in the 2 groups. In the coronal plane, mean absolute (4.3 vs 2.7 mm, respectively; P<.001) and relative (39% vs 21%, respectively; P<.001) graft extrusions were significantly greater for medial than lateral MAT. In the sagittal plane, mean absolute and relative ACMD and PCMD values were significantly greater for medial than lateral MAT (P<.001 each). For both medial and lateral MAT, mean absolute and relative ACMDs were significantly larger than PCMDs (P<.001 each). Graft extrusion>3 mm in the coronal plane was significantly more frequent in the medial (78%) than in the lateral (35%) MAT group. In the sagittal plane, the frequencies of ACMDs (72% vs 39%, respectively) and PCMDs (23% vs 4%, respectively) >3 mm were also significantly greater in the medial than in the lateral MAT group. Coronal and sagittal extrusions were not correlated with postoperative Lysholm scores for both medial and lateral MAT. The amount and incidence of graft extrusion were greater after medial than lateral MAT in both the coronal and sagittal planes. In the sagittal plane, graft extrusion was greater and more frequent on the anterior than the posterior horn in both medial and lateral MAT. However, graft extrusion was not correlated with early clinical outcomes after both medial and lateral MAT. © 2014 The Author(s).

Fabrication of TREAT Fuel with Increased Graphite Loading

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luther, Erik Paul; Leckie, Rafael M.; Dombrowski, David E.

2014-02-05

As part of the feasibility study exploring the replacement of the HEU fuel core of the TREAT reactor at Idaho National Laboratory with LEU fuel, this study demonstrates that it is possible to increase the graphite content of extruded fuel by reformulation. The extrusion process was use to fabricate the “upgrade” core1 for the TREAT reactor. The graphite content achieved is determined by calculation and has not been measured by any analytical method. In conjunction, a technique, Raman Spectroscopy, has been investigated for measuring the graphite content. This method shows some promise in differentiating between carbon and graphite; however, standardsmore » that would allow the technique to be calibrated to quantify the graphite concentration have yet to be fabricated. Continued research into Raman Spectroscopy is on going. As part of this study, cracking of graphite extrusions due to volatile evolution during heat treatment has been largely eliminated. Continued research to optimize this extrusion method is required.« less

Development of powder metallurgy Al alloys for high temperature aircraft structural applications, phase 2

NASA Technical Reports Server (NTRS)

Chellman, D. J.

1982-01-01

In this continuing study, the development of mechanically alloyed heat resistant aluminum alloys for aircraft were studied to develop higher strength targets and higher service temperatures. The use of higher alloy additions to MA Al-Fe-Co alloys, employment of prealloyed starting materials, and higher extrusion temperatures were investigated. While the MA Al-Fe-Co alloys exhibited good retention of strength and ductility properties at elevated temperatures and excellent stability of properties after 1000 hour exposure at elevated temperatures, a sensitivity of this system to low extrusion strain rates adversely affected the level of strength achieved. MA alloys in the Al-Li family showed excellent notched toughness and property stability after long time exposures at elevated temperatures. A loss of Li during processing and the higher extrusion temperature 482 K (900 F) resulted in low mechanical strengths. Subsequent hot and cold working of the MA Al-Li had only a mild influence on properties.

Microstructure and mechanical properties of a hot-extruded Al-based composite reinforced with core-shell-structured Ti/Al3Ti

NASA Astrophysics Data System (ADS)

Zhang, Li; Wu, Bao-lin; Liu, Yu-lin

2017-12-01

An Al-based composite reinforced with core-shell-structured Ti/Al3Ti was fabricated through a powder metallurgy route followed by hot extrusion and was found to exhibit promising mechanical properties. The ultimate tensile strength and elongation of the composite sintered at 620°C for 5 h and extruded at a mass ratio of 12.75:1 reached 304 MPa and 14%, respectively, and its compressive deformation reached 60%. The promising mechanical properties are due to the core-shell-structured reinforcement, which is mainly composed of Al3Ti and Ti and is bonded strongly with the Al matrix, and to the reduced crack sensitivity of Al3Ti. The refined grains after hot extrusion also contribute to the mechanical properties of this composite. The mechanical properties might be further improved through regulating the relative thickness of Al-Ti intermetallics and Ti metal layers by adjusting the sintering time and the subsequent extrusion process.

Plasticized chitosan/polyolefin films produced by extrusion.

PubMed

Matet, Marie; Heuzey, Marie-Claude; Ajji, Abdellah; Sarazin, Pierre

2015-03-06

Plasticized chitosan and polyethylene blends were produced through a single-pass extrusion process. Using a twin-screw extruder, chitosan plasticization was achieved in the presence of an acetic acid solution and glycerol, and directly mixed with metallocene polyethylene, mPE, to produce a masterbatch. Different dilutions of the masterbatch (2, 5 and 10 wt% of plasticized chitosan), in the presence of ethylene vinyl acetate, EVA, were subsequently achieved in single screw film extrusion. Very small plasticized chitosan domains (number average diameter <5 μm) were visible in the polymeric matrix. The resulting films presented a brown color and increasing haze with chitosan plasticized content. Mechanical properties of the mPE films were affected by the presence of plasticized chitosan, but improvement was observed as a result of some compatibility between mPE and chitosan in the presence of EVA. Finally the incorporation of plasticized chitosan affected mPE water vapor permeability while oxygen permeability remained constant. Copyright © 2014 Elsevier Ltd. All rights reserved.

Gluten-Free Precooked Rice-Yellow Pea Pasta: Effect of Extrusion-Cooking Conditions on Phenolic Acids Composition, Selected Properties and Microstructure.

PubMed

Bouasla, Abdallah; Wójtowicz, Agnieszka; Zidoune, Mohammed Nasereddine; Olech, Marta; Nowak, Renata; Mitrus, Marcin; Oniszczuk, Anna

2016-05-01

Rice/yellow pea flour blend (2/1 ratio) was used to produce gluten-free precooked pasta using a single-screw modified extrusion-cooker TS-45. The effect of moisture content (28%, 30%, and 32%) and screw speed (60, 80, and 100 rpm) on some quality parameters was assessed. The phenolic acids profile and selected pasta properties were tested, like pasting properties, water absorption capacity, cooking loss, texture characteristics, microstructure, and sensory overall acceptability. Results indicated that dough moisture content influenced all tested quality parameters of precooked pasta except firmness. Screw speed showed an effect only on some quality parameters. The extrusion-cooking process at 30% of dough moisture with 80 rpm is appropriate to obtain rice-yellow pea precooked pasta with high content of phenolics and adequate quality. These pasta products exhibited firm texture, low stickiness, and regular and compact interne structure confirmed by high score in sensory overall acceptability. © 2016 Institute of Food Technologists®

Influence of enzymatic extrusion liquefaction pretreatment for Chinese rice wine on the volatiles generated from extruded rice.

PubMed

Xu, Enbo; Li, Hongyan; Wu, Zhengzong; Wang, Fang; Xu, Xueming; Jin, Zhengyu; Jiao, Aiquan

2015-01-01

Volatile compounds in enzymatic extruded rice, produced under different conditions of varying barrel temperature (BT), α-amylase concentration (AC) and moisture content (MC), were extracted and identified by headspace solid phase microextraction (HS-SPME) and gas chromatography-linked mass spectrometry (GC-MS). Statistical analyses reflected that the Maillard reaction could be inhibited both by the mild extrusion conditions and the enhanced hydrolysis caused by thermostable α-amylase. Relative amounts of total volatiles in enzymatic extruded rice were far less than those in severe processed extruded rice. Reverse-phase high-performance liquid chromatography (RP-HPLC) showed that the amino acids (AAs) involved in Maillrad reaction were utmostly preserved in extruded rice with highest amylase concentration by comparison of total AA content of different extrudates. These results suggest that enzymatic extrusion liquefaction is an effective way to control the generation of volatiles from extruded rice for Chinese rice wine production. © 2014 Institute of Food Technologists®

A Covering Type Extrusion Die with Twin Cavities for Semi-Hollow Al-Profiles

NASA Astrophysics Data System (ADS)

Deng, Rurong; Huang, Xuemei

2018-03-01

A new structure named covering type with twin cavities in a die for the semi-hollow aluminum profiles was present. The determination of structure parameters was introduced in detail. Mainly including the selection of the machine, the arrangement of portholes, the structure design of chamber and the selection of bearing. The method of checking the die strength was introduced. According to the extrusion results, the structure of the traditional solid die, the porthole die with single cavity and the covering type structure with twin cavities were compared. The characteristics of the latter structure were simple and easy to process. The practical application shows that the new die structure can enhance the die life, improve the production efficiency and reduce the cost. The high precision and the surface brightness of the profiles were obtained. The structure is worth promoting. The aim is to provide reliable data and reference for the further research and development of this technology on the extrusion die with multi-cavities in a die.

Microstructural Anisotropy of Magnetocaloric Gadolinium Cylinders: Effect on the Mechanical Properties of the Material

PubMed Central

Petrovič, Darja Steiner; Šturm, Roman; Naglič, Iztok; Markoli, Boštjan; Pepelnjak, Tomaž

2016-01-01

The development of advanced materials and technologies based on magnetocaloric Gd and its compounds requires an understanding of the dependency of mechanical properties on their underlying microstructure. Therefore, the aim of the study was to characterize microstructural inhomogeneities in the gadolinium that can be used in magnetocaloric refrigeration systems. Microstructures of magnetocaloric gadolinium cylinders were investigated by light microscopy and FE-SEM (Field Emission Scanning Electron Microscopy), EDS (Energy-dispersive X-ray Spectroscopy), and BSE (Back-scattered Electrons) in both the extrusion and the extrusion-transversal directions. XRD (X-ray Diffraction) analyses were performed to reveal the presence of calcium- and fluorine-based compounds. Metallographic characterization showed an oxidized and inhomogeneous microstructure of the cross-sections. The edges and the outer parts of the cylinders were oxidized more intensively on the surfaces directly exposed to the processing tools. Moreover, a significant morphological anisotropy of the non-metallic inclusions was observed. CaF inclusions act as active nucleation sites for internal oxidation. The non-metallic, Ca- and F-containing inclusions can be classified as complex calciumoxyfluorides. The solubility of Er and Yb in the CaF was negligible compared to the Gd matrix and/or the oxide phase. Lower mechanical properties of the material are a consequence of the lower structural integrity due to selective oxidation of surfaces and interfaces. PMID:28773502

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

PubMed

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. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterization of Tubing from Advanced ODS alloy (FCRD-NFA1)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maloy, Stuart Andrew; Aydogan, Eda; Anderoglu, Osman

2016-09-20

Fabrication methods are being developed and tested for producing fuel clad tubing of the advanced ODS 14YWT and FCRD-NFA1 ferritic alloys. Three fabrication methods were based on plastically deforming a machined thick-wall tube sample of the ODS alloys by pilgering, hydrostatic extrusion or drawing to decrease the outer diameter and wall thickness and increase the length of the final tube. The fourth fabrication method consisted of the additive manufacturing approach involving solid-state spray deposition (SSSD) of ball milled and annealed powder of 14YWT for producing thin-wall tubes. Of the four fabrication methods, two methods were successful at producing tubing formore » further characterization: production of tubing by high-velocity oxy-fuel spray forming and production of tubing using high-temperature hydrostatic extrusion. The characterization described shows through neutron diffraction the texture produced during extrusion while maintaining the beneficial oxide dispersion. In this research, the parameters for innovative thermal spray deposition and hot extrusion processing methods have been developed to produce the final nanostructured ferritic alloy (NFA) tubes having approximately 0.5 mm wall thickness. Effect of different processing routes on texture and grain boundary characteristics has been investigated. It was found that hydrostatic extrusion results in combination of plane strain and shear deformations which generate rolling textures of α- and γ-fibers on {001}<110> and {111}<110> together with a shear texture of ζ-fiber on {011}<211> and {011}<011>. On the other hand, multi-step plane strain deformation in cross directions leads to a strong rolling textures of θ- and ε-fiber on {001}<110> together with weak γ-fiber on {111}<112>. Even though the amount of the equivalent strain is similar, shear deformation leads to much lower texture indexes compared to the plane strain deformations. Moreover, while 50% of hot rolling brings about a large number of high-angle grain boundaries (HAB), 44% of shear deformation results in large amount of low-angle boundaries (LAB) showing the incomplete recrystallization.« less

Effects of Texture and Grain Size on the Yield Strength of ZK61 Alloy Rods Processed by Cyclic Extrusion and Compression

PubMed Central

Zhang, Lixin; Zhang, Wencong; Cao, Biao; Chen, Wenzhen; Duan, Junpeng; Cui, Guorong

2017-01-01

The ZK61 alloy rods with different grain sizes and crystallographic texture were successfully fabricated by cyclic extrusion and compression (CEC). Their room-temperature tension & compression yield strength displayed a significant dependence on grain size and texture, essentially attributed to {10-12} twinning. The texture variations were characterized by the angle θ between the c-axis of the grain and the extrusion direction (ED) during the process. The contour map of room-temperature yield strength as a function of grain size and the angle θ was obtained. It showed that both the tension yield strength and the compression yield strength of ZK61 alloy were fully consistent with the Hall-Patch relationship at a certain texture, but the change trends of the tension yield strength and the compression yield strength were completely opposite at the same grain size while texture altered. The friction stresses of different deformation modes calculated based on the texture confirmed the tension yield strength of the CECed ZK61 alloy rods, which was determined by both the basal slip and the tension twinning slip during the tension deformation at room temperature, while the compression yield strength was mainly determined by the basal slip during the compression deformation. PMID:29072616

Influence of processing on the microstructure and mechanical properties of 14YWT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoelzer, D. T.; Unocic, K. A.; Sokolov, Mikhail A.

2016-04-25

The investigation of the mechanical alloying (MA) conditions for producing the advanced oxide dispersion strengthened (ODS) 14YWT ferritic alloy led to significant improvements in balancing the strength, ductility and fracture toughness properties while still maintaining the salient microstructural features consisting of ultra-fine grains and high concentration of Y-, Ti- and O-enriched nanoclusters. The implemented changes to the processing conditions included reducing the contamination of the powder during ball milling, applying a pre-extrusion annealing treatment on the ball milled powder and exploring different extrusion temperatures at 850 C (SM170 heat), 1000 C (SM185) and 1150 C (SM200). The microstructural studies ofmore » the three 14YWT heats showed similarities in the dispersion of nanoclusters and sub-micron size grains, indicating the microstructure was insensitive to the different extrusion conditions. Compared to past 14YWT heats, the three new heats showed lower strength, but higher ductility levels between 25 and 800 C and significantly higher fracture toughness values between 25 C and 700 C. The lower contamination levels of O, C and N achieved with improved ball milling conditions plus the slightly larger grain size were identified as important factors for improving the balance in mechanical properties of the three heats of 14YWT.« less

Finite element analysis of the design and manufacture of thin-walled pressure vessels used as aerosol cans

NASA Astrophysics Data System (ADS)

Abdussalam, Ragba Mohamed

Thin-walled cylinders are used extensively in the food packaging and cosmetics industries. The cost of material is a major contributor to the overall cost and so improvements in design and manufacturing processes are always being sought. Shape optimisation provides one method for such improvements. Aluminium aerosol cans are a particular form of thin-walled cylinder with a complex shape consisting of truncated cone top, parallel cylindrical section and inverted dome base. They are manufactured in one piece by a reverse-extrusion process, which produces a vessel with a variable thickness from 0.31 mm in the cylinder up to 1.31 mm in the base for a 53 mm diameter can. During manufacture, packaging and charging, they are subjected to pressure, axial and radial loads and design calculations are generally outside the British and American pressure vessel codes. 'Design-by-test' appears to be the favoured approach. However, a more rigorous approach is needed in order to optimise the designs. Finite element analysis (FEA) is a powerful tool for predicting stress, strain and displacement behaviour of components and structures. FEA is also used extensively to model manufacturing processes. In this study, elastic and elastic-plastic FEA has been used to develop a thorough understanding of the mechanisms of yielding, 'dome reversal' (an inherent safety feature, where the base suffers elastic-plastic buckling at a pressure below the burst pressure) and collapse due to internal pressure loading and how these are affected by geometry. It has also been used to study the buckling behaviour under compressive axial loading. Furthermore, numerical simulations of the extrusion process (in order to investigate the effects of tool geometry, friction coefficient and boundary conditions) have been undertaken. Experimental verification of the buckling and collapse behaviours has also been carried out and there is reasonable agreement between the experimental data and the numerical predictions.

Effect of Extrusion Parameters on Texture and Microstructure Evolution of Extruded Mg-1 pctMn and Mg-1 pctMn-Sr Alloys

NASA Astrophysics Data System (ADS)

Borkar, Hemant; Pekguleryuz, Mihriban

2015-01-01

Three Mg alloys Mg-1 pctMn (M1), Mg-1 pctMn-1.3 pctSr, and Mg-1 pctMn-2.1 pctSr were subjected to two different extrusion temperatures and two different extrusion speeds in lab-scale extrusion. The extrusion temperatures of 573 K and 673 K (300 °C and 400 °C) and two ram speeds of 4 and 8 mm/s were used at constant extrusion ratio of 7. M1 exhibited strong basal texture after extrusion at 673 K (400 °C) at higher speed. At 573 K (300 °C), recrystallization in all alloys takes place completely or partially by continuous dynamic recrystallization mechanism, while particle stimulated nucleation (PSN) occurs in all M1-Sr alloys at both extrusion temperatures and speeds. At 673 K (400 °C), grain boundary bulging is the only recrystallization mechanism in alloy M1, while it occurs in combination with PSN in M1-Sr alloys. The effect of texture weakening by PSN is more significant in M1-Sr alloys extruded at 573 K (400 °C). The plant extrusion trials were carried out on Mg-1 pctMn, Mg-1 pctMn-0.3 pctSr, and Mg-1 pctMn-2.1 pctSr at 623 K (350 °C) with different speeds than in lab-scale extrusion. M1 alloy exhibited strong basal texture at both speeds, while Sr additions of 0.3 and 2.1 pct promoted similar amount of texture weakening.

Blown film extrusion of poly(lactic acid) without melt strength enhancers

Treesearch

Sonal S. Karkhanis; Nicole M. Stark; Ronald C. Sabo; Laurent M. Matuana

2017-01-01

Processing strategies were developed to manufacture poly(lactic acid) (PLA) blown films without melt strength enhancers (MSEs). The effects of processing temperature on PLA’s melt properties (shear and elongational viscosities), PLA grades, and other processing conditions [ratio of take-up roller to extruder’s rotational screw speeds or processing speed ratio (PSR) and...

A review of pharmaceutical extrusion: critical process parameters and scaling-up.

PubMed

Thiry, J; Krier, F; Evrard, B

2015-02-01

Hot melt extrusion has been a widely used process in the pharmaceutical area for three decades. In this field, it is important to optimize the formulation in order to meet specific requirements. However, the process parameters of the extruder should be as much investigated as the formulation since they have a major impact on the final product characteristics. Moreover, a design space should be defined in order to obtain the expected product within the defined limits. This gives some freedom to operate as long as the processing parameters stay within the limits of the design space. Those limits can be investigated by varying randomly the process parameters but it is recommended to use design of experiments. An examination of the literature is reported in this review to summarize the impact of the variation of the process parameters on the final product properties. Indeed, the homogeneity of the mixing, the state of the drug (crystalline or amorphous), the dissolution rate, the residence time, can be influenced by variations in the process parameters. In particular, the impact of the following process parameters: temperature, screw design, screw speed and feeding, on the final product, has been reviewed. Copyright © 2014 Elsevier B.V. All rights reserved.

Role of E-cadherin in membrane-cortex interaction probed by nanotube extrusion.

PubMed

Tabdanov, Erdem; Borghi, Nicolas; Brochard-Wyart, Françoise; Dufour, Sylvie; Thiery, Jean-Paul

2009-03-18

This study aims to define the role of E-cadherin (Ecad) engagement in cell-cell contact during membrane-cortex interaction. As a tool, we used a hydrodynamic membrane tube extrusion technique to characterize the mechanical interaction between the plasma membrane and the underlying cortical cytoskeleton. Cells were anchored on 4.5 microm beads coated with polylysine (PL) to obtain nonspecific cell adhesion or with an antibody against Ecad to mimic specific Ecad-mediated cell adhesion. We investigated tube length dynamics L(t) over time and through successive extrusions applied to the cell at regular time intervals. A constant slow velocity was observed for the first extrusion, for PL-attached cells. Subsequent extrusions had two phases: an initial high-velocity regime followed by a low-velocity regime. Successive extrusions gradually weakened the binding of the membrane around the tube neck to the underlying cortical cytoskeleton. Cells specifically attached via Ecad first exhibited a very low extrusion velocity regime followed by a faster extrusion regime similar to nonspecific extrusion. This indicates that Ecad strengthens the membrane-cortical cytoskeleton interaction, but only in a restricted area corresponding to the site of contact between the cell and the bead. Occasional giant "cortex" tubes were extruded with specifically anchored cells, demonstrating that the cortex remained tightly bound to the membrane through Ecad-mediated adhesion at the contact site.

Role of E-Cadherin in Membrane-Cortex Interaction Probed by Nanotube Extrusion

PubMed Central

Tabdanov, Erdem; Borghi, Nicolas; Brochard-Wyart, Françoise; Dufour, Sylvie; Thiery, Jean-Paul

2009-01-01

This study aims to define the role of E-cadherin (Ecad) engagement in cell-cell contact during membrane-cortex interaction. As a tool, we used a hydrodynamic membrane tube extrusion technique to characterize the mechanical interaction between the plasma membrane and the underlying cortical cytoskeleton. Cells were anchored on 4.5 μm beads coated with polylysine (PL) to obtain nonspecific cell adhesion or with an antibody against Ecad to mimic specific Ecad-mediated cell adhesion. We investigated tube length dynamics L(t) over time and through successive extrusions applied to the cell at regular time intervals. A constant slow velocity was observed for the first extrusion, for PL-attached cells. Subsequent extrusions had two phases: an initial high-velocity regime followed by a low-velocity regime. Successive extrusions gradually weakened the binding of the membrane around the tube neck to the underlying cortical cytoskeleton. Cells specifically attached via Ecad first exhibited a very low extrusion velocity regime followed by a faster extrusion regime similar to nonspecific extrusion. This indicates that Ecad strengthens the membrane-cortical cytoskeleton interaction, but only in a restricted area corresponding to the site of contact between the cell and the bead. Occasional giant “cortex” tubes were extruded with specifically anchored cells, demonstrating that the cortex remained tightly bound to the membrane through Ecad-mediated adhesion at the contact site. PMID:19289070

Induction and quantification of collagen fiber alignment in a three-dimensional hydroxyapatite-collagen composite scaffold.

PubMed

Banglmaier, Richard F; Sander, Edward A; VandeVord, Pamela J

2015-04-01

Hydroxyapatite-collagen composite scaffolds are designed to serve as a regenerative load bearing replacement that mimics bone. However, the material properties of these scaffolds are at least an order of magnitude less than that of bone and subject to fail under physiological loading conditions. These scaffolds compositionally resemble bone but they do not possess important structural attributes such as an ordered arrangement of collagen fibers, which is a correlate to the mechanical properties in bone. Furthermore, it is unclear how much ordering of structure is satisfactory to mimic bone. Therefore, quantitative methods are needed to characterize collagen fiber alignment in these scaffolds for better correlation between the scaffold structure and the mechanical properties. A combination of extrusion and compaction was used to induce collagen fiber alignment in composite scaffolds. Collagen fiber alignment, due to extrusion and compaction, was quantified from polarized light microscopy images with a Fourier transform image processing algorithm. The Fourier transform method was capable of resolving the degree of collagen alignment from polarized light images. Anisotropy indices of the image planes ranged from 0.08 to 0.45. Increases in the degree of fiber alignment induced solely by extrusion (0.08-0.25) or compaction (0.25-0.44) were not as great as those by the combination of extrusion and compaction (0.35-0.45). Additional measures of randomness and fiber direction corroborate these anisotropy findings. This increased degree of collagen fiber alignment was induced in a preferred direction that is consistent with the extrusion direction and parallel with the compacted plane. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Experimental and numerical investigation of ram extrusion of bread dough

NASA Astrophysics Data System (ADS)

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.

Increased dissolution rates of tranilast solid dispersions extruded with inorganic excipients.

PubMed

Maniruzzaman, Mohammed; Ross, Steven A; Islam, Muhammad Tariqul; Scoutaris, Nikolaos; Nair, Arun; Douroumis, Dennis

2017-06-01

The purpose of this study was to evaluate the performance of Neusilin® (NEU) a synthetic magnesium aluminometasilicate as an inorganic drug carrier co-processed with the hydrophilic surfactants Labrasol and Labrafil to develop Tranilast (TLT)-based solid dispersions using continuous melt extrusion (HME) processing. Twin-screw extrusion was optimized to develop various TLT/excipient/surfactant formulations followed by continuous capsule filling in the absence of any downstream equipment. Physicochemical characterization showed the existence of TLT in partially crystalline state in the porous network of inorganic NEU for all extruded formulations. Furthermore, in-line NIR studies revealed a possible intermolecular H-bonding formation between the drug and the carrier resulting in the increase of TLT dissolution rates. The capsules containing TLT-extruded solid dispersions showed enhanced dissolution rates and compared with the marketed Rizaben ® product.

Poly(lactic acid) (PLA) Based Tear Resistant and Biodegradable Flexible Films by Blown Film Extrusion

PubMed Central

Mallegni, Norma; Phuong, Thanh Vu; Coltelli, Maria-Beatrice

2018-01-01

Poly(lactic acid) (PLA) was melt mixed in a laboratory extruder with poly(butylene adipate-co-terephthalate) (PBAT) and poly(butylene succinate) (PBS) in the presence of polypropylene glycol di glycidyl ether (EJ400) that acted as both plasticizer and compatibilizer. The process was then scaled up in a semi-industrial extruder preparing pellets having different content of a nucleating agent (LAK). All of the formulations could be processed by blowing extrusion and the obtained films showed mechanical properties dependent on the LAK content. In particular the tearing strength showed a maximum like trend in the investigated composition range. The films prepared with both kinds of blends showed a tensile strength in the range 12–24 MPa, an elongation at break in the range 150–260% and a significant crystallinity. PMID:29342099

Hydrostatic extrusion of Cu-Ag melt spun ribbon

DOEpatents

Hill, M.A.; Bingert, J.F.; Bingert, S.A.; Thoma, D.J.

1998-09-08

The present invention provides a method of producing high-strength and high-conductance copper and silver materials comprising the steps of combining a predetermined ratio of the copper with the silver to produce a composite material, and melt spinning the composite material to produce a ribbon of copper and silver. The ribbon of copper and silver is heated in a hydrogen atmosphere, and thereafter die pressed into a slug. The slug then is placed into a high-purity copper vessel and the vessel is sealed with an electron beam. The vessel and slug then are extruded into wire form using a cold hydrostatic extrusion process. 5 figs.

Effects of Graphene Oxide Addition on Mechanical and Thermal Properties of Evoh Films

NASA Astrophysics Data System (ADS)

González-Ruiz, Jesús; Yataco-Lazaro, Lourde; Virginio, Sueli; das Graças da Silva-Valenzuela, Maria; Moura, Esperidiana; Valenzuela-Díaz, Francisco

Currently, ethylene vinyl alcohol (EVOH) is one of the oxygen barrier materials most used for food packaging. The addition of graphene oxide nanosheets to the EVOH matrix is employed to improve their mechanic al and barrier properties. In this work, films of EVOH-based composites reinforced with graphene oxide were prepared by melt extrusion, using a twin screw extruder machine and blown extrusion process. The graphene oxide was prepared via chemical oxidation of natural graphite and then was exfoliated into nanosheets using the sonochemical method. The composite films samples were characterized using FTIR and DSC analysis. In addition, their mechanical properties were also determined.

Numerical simulation and experiment on effect of ultrasonic in polymer extrusion processing

NASA Astrophysics Data System (ADS)

Wan, Yue; Fu, ZhiHong; Wei, LingJiao; Zang, Gongzheng; Zhang, Lei

2018-01-01

The influence of ultrasonic wave on the flow field parameters and the precision of extruded products are studied. Firstly, the effect of vibration power on the average velocity of the outlet, the average viscosity of the die section, the average shear rate and the inlet pressure of the die section were studied by using the Polyflow software. Secondly, the effects of ultrasonic strength on the die temperature and the drop of die pressure were studied experimentally by different head temperature and different screw speed. Finally, the relationship between die pressure and extrusion flow rate under different ultrasonic power were studied through experiments.

Hydrostatic extrusion of Cu-Ag melt spun ribbon

DOEpatents

Hill, Mary Ann; Bingert, John F.; Bingert, Sherri A.; Thoma, Dan J.

1998-01-01

The present invention provides a method of producing high-strength and high-conductance copper and silver materials comprising the steps of combining a predetermined ratio of the copper with the silver to produce a composite material, and melt spinning the composite material to produce a ribbon of copper and silver. The ribbon of copper and silver is heated in a hydrogen atmosphere, and thereafter die pressed into a slug. The slug then is placed into a high-purity copper vessel and the vessel is sealed with an electron beam. The vessel and slug then are extruded into wire form using a cold hydrostatic extrusion process.

Precooked bran-enriched wheat flour using extrusion: dietary fiber profile and sensory characteristics.

PubMed

Gajula, H; Alavi, S; Adhikari, K; Herald, T

2008-05-01

The effect of precooking by extrusion processing on the dietary fiber profile of wheat flour substituted with 0%, 10%, 20%, and 30% wheat bran was evaluated. Depending on the level of bran, total dietary fiber (TDF) and soluble dietary fiber (SDF) in uncooked flours ranged from 4.2% to 17.2% and 1.5% to 2.4%, respectively. Precooking by extrusion significantly increased SDF in flours (by 22% to 73%); although in most cases it also led to a significant decrease in TDF. Cookies and tortillas produced from uncooked and precooked flours with 0% and 20% substituted bran were evaluated for consumer acceptability using a 9-point hedonic scale. With a few exceptions, all cookies had scores ranging from 6 to 7 ("like slightly" to "like moderately") for each attribute, including overall acceptability, appearance, texture, crumbliness, and flavor. Tortillas were rated for the same attributes except for crumbliness, which was replaced with chewiness. In most cases, tortilla scores ranged from 5 to 7 ("neither like nor dislike" to "like moderately"). Consumer acceptability scores of cookies from uncooked flour did not change significantly with increase in bran substitution from 0% to 20%. However, consumer scores for tortillas did decrease significantly with increase in bran level. Extrusion precooking of the flours did not improve the consumer acceptability of cookies and tortillas; however, it did improve their dietary fiber profile by increasing the SDF significantly.

Desensitization of atriopeptin stimulated accumulation and extrusion of cyclic GMP from a kidney epithelial cell line (MDCK).

PubMed

Woods, M; Houslay, M D

1991-02-01

Atriopeptin caused dose- (EC50 ca. 2 x 10(-8) M) and time-dependent increases in the intracellular concentration of cyclic GMP in the MDCK kidney epithelial cell line; an effect potentiated by the phosphodiesterase inhibitor, IBMX. The atriopeptin-catalysed increase in cyclic GMP was transient and reached a maximum some 10-20 min after challenge of cells with atriopeptin. The basis for the transience of this increase was shown to be due to the desensitization of guanylate cyclase coupled with extrusion of cyclic GMP from the cells and the degradation of cyclic GMP by phosphodiesterase activity. Atriopeptin-catalysed extrusion of cyclic GMP was time- and dose-(EC50 ca. 1.5 x 10(-8) M) dependent and was inhibited by probenecid but not by high external cyclic GMP concentrations. The extrusion process underwent apparent desensitization as did guanylate cyclase with similar half lives (T1/2 of ca. 20 min). Desensitization was dose-dependent upon atriopeptin and did not appear to be mediated by elevated cyclic GMP concentrations as pre-incubation with 8-bromo cyclic GMP did not cause desensitization and the half-times for desensitization were similar whether or not IBMX was present. The majority of the cyclic nucleotide phosphodiesterase activity was found in the cytosol fraction of the cells and could be separated into two cyclic AMP specific forms and two cyclic GMP preferring forms.

Extrusion conditions affect chemical composition and in vitro digestion of select food ingredients.

PubMed

Dust, Jolene M; Gajda, Angela M; Flickinger, Elizabeth A; Burkhalter, Toni M; Merchen, Neal R; Fahey, George C

2004-05-19

An experiment was conducted to determine the effects of extrusion conditions on chemical composition and in vitro hydrolytic and fermentative digestion of barley grits, cornmeal, oat bran, soybean flour, soybean hulls, and wheat bran. Extrusion conditions altered crude protein, fiber, and starch concentrations of ingredients. Organic matter disappearance (OMD) increased for extruded versus unprocessed samples of barley grits, cornmeal, and soybean flour that had been hydrolytically digested. After 8 h of fermentative digestion, OMD decreased as extrusion conditions intensified for barley grits and cornmeal but increased for oat bran, soybean hulls, and wheat bran. Total short-chain fatty acid production decreased as extrusion conditions intensified for barley grits, soybean hulls, and soybean flour. These data suggest that the effects of extrusion conditions on ingredient composition and digestion are influenced by the unique chemical characteristics of individual substrates.

Microdissection of black widow spider silk-producing glands.

PubMed

Jeffery, Felicia; La Mattina, Coby; Tuton-Blasingame, Tiffany; Hsia, Yang; Gnesa, Eric; Zhao, Liang; Franz, Andreas; Vierra, Craig

2011-01-11

Modern spiders spin high-performance silk fibers with a broad range of biological functions, including locomotion, prey capture and protection of developing offspring. Spiders accomplish these tasks by spinning several distinct fiber types that have diverse mechanical properties. Such specialization of fiber types has occurred through the evolution of different silk-producing glands, which function as small biofactories. These biofactories manufacture and store large quantities of silk proteins for fiber production. Through a complex series of biochemical events, these silk proteins are converted from a liquid into a solid material upon extrusion. Mechanical studies have demonstrated that spider silks are stronger than high-tensile steel. Analyses to understand the relationship between the structure and function of spider silk threads have revealed that spider silk consists largely of proteins, or fibroins, that have block repeats within their protein sequences. Common molecular signatures that contribute to the incredible tensile strength and extensibility of spider silks are being unraveled through the analyses of translated silk cDNAs. Given the extraordinary material properties of spider silks, research labs across the globe are racing to understand and mimic the spinning process to produce synthetic silk fibers for commercial, military and industrial applications. One of the main challenges to spinning artificial spider silk in the research lab involves a complete understanding of the biochemical processes that occur during extrusion of the fibers from the silk-producing glands. Here we present a method for the isolation of the seven different silk-producing glands from the cobweaving black widow spider, which includes the major and minor ampullate glands [manufactures dragline and scaffolding silk], tubuliform [synthesizes egg case silk], flagelliform [unknown function in cob-weavers], aggregate [makes glue silk], aciniform [synthesizes prey wrapping and egg case threads] and pyriform [produces attachment disc silk]. This approach is based upon anesthetizing the spider with carbon dioxide gas, subsequent separation of the cephalothorax from the abdomen, and microdissection of the abdomen to obtain the silk-producing glands. Following the separation of the different silk-producing glands, these tissues can be used to retrieve different macromolecules for distinct biochemical analyses, including quantitative real-time PCR, northern- and western blotting, mass spectrometry (MS or MS/MS) analyses to identify new silk protein sequences, search for proteins that participate in the silk assembly pathway, or use the intact tissue for cell culture or histological experiments.

Integrated, multi-parameter, investigation of eruptive dynamics at Santiaguito lava dome, Guatemala

NASA Astrophysics Data System (ADS)

Lavallée, Yan; De Angelis, Silvio; Rietbrock, Andreas; Lamb, Oliver; Hornby, Adrian; Lamur, Anthony; Kendrick, Jackie E.; von Aulock, Felix W.; Chigna, Gustavo

2016-04-01

Understanding the nature of the signals generated at volcanoes is central to hazard mitigation efforts. Systematic identification and understanding of the processes responsible for the signals associated with volcanic activity are only possible when high-resolution data are available over relatively long periods of time. For this reason, in November 2014, the Liverpool Earth Observatory (LEO), UK, in collaboration with colleagues of the Instituto Nacional de Sismologia, Meteorologia e Hidrologia (INSIVUMEH), Guatemala, installed a large multi-parameter geophysical monitoring network at Santiaguito - the most active volcano in Guatemala. The network, which is to date the largest temporary deployment on Santiaguito, includes nine three-component broadband seismometers, three tiltmeters, and five infrasound microphones. Further, during the initial installation campaign we conducted visual and thermal infrared measurements of surface explosive activity and collected numerous rock samples for geochemical, geophysical and rheological characterisation. Activity at Santiaguito began in 1922, with the extrusion of a series of lava domes. In recent years, persistent dome extrusion has yielded spectacularly episodic piston-like motion displayed by characteristic tilt/seismic patterns (Johnson et al, 2014). This cyclicity episodically concludes with gas emissions or gas-and-ash explosions, observed to progress along a complex fault system in the dome. The explosive activity is associated with distinct geophysical signals characterised by the presence of very-long period earthquakes as well as more rapid inflation/deflation cycles; the erupted ash further evidences partial melting and thermal vesiculation resulting from fault processes (Lavallée et al., 2015). One year of data demonstrates the regularity of the periodicity and intensity of the explosions; analysis of infrasound data suggests that each explosion expulses on the order of 10,000-100,000 kg of gas and ash. We conclude that near-field monitoring of this volcanic system promises to greatly advance our understanding of shallow volcanic processes. This work was funded by the Liverpool Earth Observatory and by the European Research Council grant on Strain Localisation in Magma (SLiM, No. 306488) Reference Johnson J. B., Lyons J. J., Andrews B. J., Lees J. M., 2014. Explosive dome eruptions modulated by periodic gas-driven inflation. Geophysical Research Letters 41, 6689-6697. Lavallée Y., Dingwell D.B., Cimarelli C., Hornby A.J. Johnson J.B., Kendrick J.E., von Aulock F.W., Wadsworth F.W., Rhodes E., Kennedy B.M., Andrews B.J., Chigna G., 2015. Thermal vesiculation during volcanic eruptions. Nature 528, 544-547.

Properties of Rolled AZ31 Magnesium Alloy Sheet Fabricated by Continuous Variable Cross-Section Direct Extrusion

NASA Astrophysics Data System (ADS)

Liu, Yang; Li, Feng; Li, Xue Wen; Shi, Wen Yong

2018-03-01

Rolling is currently a widely used method for manufacturing and processing high-performance magnesium alloy sheets and has received widespread attention in recent years. Here, we combined continuous variable cross-section direct extrusion (CVCDE) and rolling processes. The microstructure and mechanical properties of the resulting sheets rolled at different temperatures from CVCDE extrudate were investigated by optical microscopy, scanning electron microscope, transmission electron microscopy and electron backscatter diffraction. The results showed that a fine-grained microstructure was present with an average grain size of 3.62 μm in sheets rolled from CVCDE extrudate at 623 K. Dynamic recrystallization and a large strain were induced by the multi-pass rolling, which resulted in grain refinement. In the 573-673 K range, the yield strength, tensile strength and elongation initially increased and then declined as the CVCDE temperature increased. The above results provide an important scientific basis of processing, manufacturing and the active control on microstructure and property for high-performance magnesium alloy sheet.

Effect of different levels of rice bran processed by various techniques on performance of broiler chicks.

PubMed

Mujahid, A; Ul Haq, I; Asif, M; Hussain Gilani, A

2004-06-01

1. Rice bran processed by extrusion cooking, roasting or pelleting and treated with antioxidant was used in broiler starter and finisher diets at various concentrations up to 500 g/kg. 2. Extrusion cooking gave the best performance, followed by roasting, while non-significant differences were observed between raw and pelleted bran. 3. Increasing the amount of rice bran in broiler diets resulted in significantly negative effects on growth performance. Non-significant differences were observed in mortality and dressing percentage due to different processes and concentrations of rice bran in the diet. Organ weights were significantly higher on raw and pelleted rice bran as compared to extruded and roasted bran. Liver and heart weights significantly increased with increasing contents of rice bran above 200g/kg, while pancreas weight increased with an addition of rice bran. 4. Treating the rice bran with antioxidant up to 250ppm had non-significant effects on broiler performance.

Solution of magnetohydrodynamic flow and heat transfer of radiative viscoelastic fluid with temperature dependent viscosity in wire coating analysis

PubMed Central

Khan, Muhammad Altaf; Siddiqui, Nasir; Ullah, Murad; Shah, Qayyum

2018-01-01

Wire coating process is a continuous extrusion process for primary insulation of conducting wires with molten polymers for mechanical strength and protection in aggressive environments. In the present study, radiative melt polymer satisfying third grade fluid model is used for wire coating process. The effect of magnetic parameter, thermal radiation parameter and temperature dependent viscosity on wire coating analysis has been investigated. Reynolds model and Vogel’s models have been incorporated for variable viscosity. The governing equations characterizing the flow and heat transfer phenomena are solved analytically by utilizing homotopy analysis method (HAM). The computed results are also verified by ND-Solve method (Numerical technique) and Adomian Decomposition Method (ADM). The effect of pertinent parameters is shown graphically. In addition, the instability of the flow in the flows of the wall of the extrusion die is well marked in the case of the Vogel model as pointed by Nhan-Phan-Thien. PMID:29596448

Nonequivalence of maternal centrosomes/centrioles in starfish oocytes: selective casting-off of reproductive centrioles into polar bodies.

PubMed

Uetake, Yumi; Kato, Koichi H; Washitani-Nemoto, Setsuko; Nemoto Si, Shin-ichi

2002-07-01

It is believed that in most animals only the paternal centrosome provides the division poles for mitosis in zygotes. This paternal inheritance of the centrosomes depends on the selective loss of the maternal centrosome. In order to understand the mechanism of centrosome inheritance, the behavior of all maternal centrosomes/centrioles was investigated throughout the meiotic and mitotic cycles by using starfish eggs that had polar body (PB) formation suppressed. In starfish oocytes, the centrioles do not duplicate during meiosis II. Hence, each centrosome of the meiosis II spindle has only one centriole, whereas in meiosis I, each has a pair of centrioles. When two pairs of meiosis I centrioles were retained in the cytoplasm of oocytes by complete suppression of PB extrusion, they separated into four single centrioles in meiosis II. However, after completion of the meiotic process, only two of the four single centrioles were found in addition to the pronucleus. When the two single centrioles of a meiosis II spindle were retained in the oocyte cytoplasm by suppressing the extrusion of the second PB, only one centriole was found with the pronucleus after the completion of the meiotic process. When these PB-suppressed eggs were artificially activated to drive the mitotic cycles, all the surviving single centrioles duplicated repeatedly to form pairs of centrioles, which could organize mitotic spindles. These results indicate that the maternal centrioles are not equivalent in their intrinsic stability and reproductive capacity. The centrosomes with the reproductive centrioles are selectively cast off into the PBs, resulting in the mature egg inheriting a nonreproductive centriole, which would degrade shortly after the completion of meiosis. (c) 2002 Elsevier Science (USA).

Aerosol Emission Monitoring and Assessment of Potential Exposure to Multi-walled Carbon Nanotubes in the Manufacture of Polymer Nanocomposites

PubMed Central

Thompson, Drew; Chen, Sheng-Chieh; Wang, Jing; Pui, David Y.H.

2015-01-01

Recent animal studies have shown that carbon nanotubes (CNTs) may pose a significant health risk to those exposed in the workplace. To further understand this potential risk, effort must be taken to measure the occupational exposure to CNTs. Results from an assessment of potential exposure to multi-walled carbon nanotubes (MWCNTs) conducted at an industrial facility where polymer nanocomposites were manufactured by an extrusion process are presented. Exposure to MWCNTs was quantified by the thermal-optical analysis for elemental carbon (EC) of respirable dust collected by personal sampling. All personal respirable samples collected (n = 8) had estimated 8-h time weighted average (TWA) EC concentrations below the limit of detection for the analysis which was about one-half of the recommended exposure limit for CNTs, 1 µg EC/m3 as an 8-h TWA respirable mass concentration. Potential exposure sources were identified and characterized by direct-reading instruments and area sampling. Area samples analyzed for EC yielded quantifiable mass concentrations inside an enclosure where unbound MWCNTs were handled and near a pelletizer where nanocomposite was cut, while those analyzed by electron microscopy detected the presence of MWCNTs at six locations throughout the facility. Through size selective area sampling it was identified that the airborne MWCNTs present in the workplace were in the form of large agglomerates. This was confirmed by electron microscopy where most of the MWCNT structures observed were in the form of micrometer-sized ropey agglomerates. However, a small fraction of single, free MWCNTs was also observed. It was found that the high number concentrations of nanoparticles, ~200000 particles/cm3, present in the manufacturing facility were likely attributable to polymer fumes produced in the extrusion process. PMID:26209597

Optimising Drug Solubilisation in Amorphous Polymer Dispersions: Rational Selection of Hot-melt Extrusion Processing Parameters.

PubMed

Li, Shu; Tian, Yiwei; Jones, David S; Andrews, Gavin P

2016-02-01

The aim of this article was to construct a T-ϕ phase diagram for a model drug (FD) and amorphous polymer (Eudragit® EPO) and to use this information to understand the impact of how temperature-composition coordinates influenced the final properties of the extrudate. Defining process boundaries and understanding drug solubility in polymeric carriers is of utmost importance and will help in the successful manufacture of new delivery platforms for BCS class II drugs. Physically mixed felodipine (FD)-Eudragit(®) EPO (EPO) binary mixtures with pre-determined weight fractions were analysed using DSC to measure the endset of melting and glass transition temperature. Extrudates of 10 wt% FD-EPO were processed using temperatures (110°C, 126°C, 140°C and 150°C) selected from the temperature-composition (T-ϕ) phase diagrams and processing screw speed of 20, 100 and 200rpm. Extrudates were characterised using powder X-ray diffraction (PXRD), optical, polarised light and Raman microscopy. To ensure formation of a binary amorphous drug dispersion (ADD) at a specific composition, HME processing temperatures should at least be equal to, or exceed, the corresponding temperature value on the liquid-solid curve in a F-H T-ϕ phase diagram. If extruded between the spinodal and liquid-solid curve, the lack of thermodynamic forces to attain complete drug amorphisation may be compensated for through the use of an increased screw speed. Constructing F-H T-ϕ phase diagrams are valuable not only in the understanding drug-polymer miscibility behaviour but also in rationalising the selection of important processing parameters for HME to ensure miscibility of drug and polymer.

Consolidation of Fe16N2 Magnets Using Equal Channel Angular Extrusion

DTIC Science & Technology

2015-06-11

industry such as powder metallurgy and hot deformation. The latter require treatments at high temperatures, typically around 1000 oC. In this work...have any deteriorating effects on the magnetization values (compared to the powder ). However, extrusions at temperatures ~150 oC result in a small...Extrusions at temperatures up to ~150 oC do not have any deteriorating effects on the magnetization values (compared to the powder ). However, extrusions at

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

PubMed

Bingöl, Sedat; Bozacı, Atilla

2015-07-17

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.

Effects of extrusion conditions on the extrusion responses and the quality of brown rice pasta.

PubMed

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Processing research and development of 'green' polymer nanoclay composites containing a polyhydroxybutyrate, vinyl acetates, and modified montmorillonite clay

NASA Astrophysics Data System (ADS)

McKirahan, James N., Jr.

The purpose of this research was to determine the feasibility of direct melt-blending (intercalation) montmorillonite nanoclay to polyhydroxybutyrate along with vinyl acetate, at different weight percentages, to enhance plasticization using typical plastic processing equipment and typical processing methodology. The purpose was to determine and compare the specific mechanical properties of tensile strength and flexural strength developed as a result from this processing. Single screw and twin screw extrusion, Banbury mixer compounding, and compression molding were used to intercalate montmorillonite, and for sample preparation purposes, to test tensile and flexural strength of the resultant polymer clay nanocomposites (PCN). Results indicate Polyhydroxybutyrate and Ethylene vinyl acetate, and weight percentages of 70%, 65% and 60% PHB, and 15%, 20%, and 25% of EVA, respectively, influenced mechanical properties. The resultant materials remained in a mostly amorphous state. The nanoclay, at specific weight percentage of 10%, acted as an antimicrobial and preservative for the materials produced during the research. The intention of the research was to promote knowledge and understanding concerning these materials and processes so technology transfer regarding the use, mechanical properties, manufacture, and process ability of these bio-friendly materials to academia, industry, and society can occur.

Powder Metallurgy of Uranium Alloy Fuels for TRU-Burning Reactors Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDeavitt, Sean M

2011-04-29

Overview Fast reactors were evaluated to enable the transmutation of transuranic isotopes generated by nuclear energy systems. The motivation for this was that TRU isotopes have high radiotoxicity and relatively long half-lives, making them unattractive for disposal in a long-term geologic repository. Fast reactors provide an efficient means to utilize the energy content of the TRUs while destroying them. An enabling technology that requires research and development is the fabrication metallic fuel containing TRU isotopes using powder metallurgy methods. This project focused upon developing a powder metallurgical fabrication method to produce U-Zr-transuranic (TRU) alloys at relatively low processing temperatures (500ºCmore » to 600ºC) using either hot extrusion or alpha-phase sintering for charecterization. Researchers quantified the fundamental aspects of both processing methods using surrogate metals to simulate the TRU elements. The process produced novel solutions to some of the issues relating to metallic fuels, such as fuel-cladding chemical interactions, fuel swelling, volatility losses during casting, and casting mold material losses. Workscope There were two primary tasks associated with this project: 1. Hot working fabrication using mechanical alloying and extrusion • Design, fabricate, and assemble extrusion equipment • Extrusion database on DU metal • Extrusion database on U-10Zr alloys • Extrusion database on U-20xx-10Zr alloys • Evaluation and testing of tube sheath metals 2. Low-temperature sintering of U alloys • Design, fabricate, and assemble equipment • Sintering database on DU metal • Sintering database on U-10Zr alloys • Liquid assisted phase sintering on U-20xx-10Zr alloys Appendices Outline Appendix A contains a Fuel Cycle Research & Development (FCR&D) poster and contact presentation where TAMU made primary contributions. Appendix B contains MSNE theses and final defense presentations by David Garnetti and Grant Helmreich outlining the beginning of the materials processing setup. Also included within this section is a thesis proposal by Jeff Hausaman. Appendix C contains the public papers and presentations introduced at the 2010 American Nuclear Society Winter Meeting. Appendix A—MSNE theses of David Garnetti and Grant Helmreich and proposal by Jeff Hausaman A.1 December 2009 Thesis by David Garnetti entitled “Uranium Powder Production Via Hydride Formation and Alpha Phase Sintering of Uranium and Uranium-Zirconium Alloys for Advanced Nuclear Fuel Applications” A.2 September 2009 Presentation by David Garnetti (same title as document in Appendix B.1) A.3 December 2010 Thesis by Grant Helmreich entitled “Characterization of Alpha-Phase Sintering of Uranium and Uranium-Zirconium Alloys for Advanced Nuclear Fuel Applications” A.4 October 2010 Presentation by Grant Helmreich (same title as document in Appendix B.3) A.5 Thesis Proposal by Jeffrey Hausaman entitled “Hot Extrusion of Alpha Phase Uranium-Zirconium Alloys for TRU Burning Fast Reactors” Appendix B—External presentations introduced at the 2010 ANS Winter Meeting B.1 J.S. Hausaman, D.J. Garnetti, and S.M. McDeavitt, “Powder Metallurgy of Alpha Phase Uranium Alloys for TRU Burning Fast Reactors,” Proceedings of 2010 ANS Winter Meeting, Las Vegas, Nevada, USA, November 7-10, 2010 B.2 PowerPoint Presentation Slides from C.1 B.3 G.W. Helmreich, W.J. Sames, D.J. Garnetti, and S.M. McDeavitt, “Uranium Powder Production Using a Hydride-Dehydride Process,” Proceedings of 2010 ANS Winter Meeting, Las Vegas, Nevada, USA, November 7-10, 2010 B.4. PowerPoint Presentation Slides from C.3 B.5 Poster Presentation from C.3 Appendix C—Fuel cycle research and development undergraduate materials and poster presentation C.1 Poster entitled “Characterization of Alpha-Phase Sintering of Uranium and Uranium-Zirconium Alloys” presented at the Fuel Cycle Technologies Program Annual Meeting C.2 April 2011 Honors Undergraduate Thesis by William Sames, Research Fellow, entitled “Uranium Metal Powder Production, Particle Distribution Analysis, and Reaction Rate Studies of a Hydride-Dehydride Process"« less

Hot-melt extrusion as a continuous manufacturing process to form ternary cyclodextrin inclusion complexes.

PubMed

Thiry, Justine; Krier, Fabrice; Ratwatte, Shenelka; Thomassin, Jean-Michel; Jerome, Christine; Evrard, Brigitte

2017-01-01

The aim of this study was to evaluate hot-melt extrusion (HME) as a continuous process to form cyclodextrin (CD) inclusion complexes in order to increase the solubility and dissolution rate of itraconazole (ITZ), a class II model drug molecule of the Biopharmaceutics Classification System. Different CD derivatives were tested in a 1:1 (CD:ITZ) molar ratio to obtain CD ternary inclusion complexes in the presence of a polymer, namely Soluplus ® (SOL). The CD used in this series of experiments were β-cyclodextrin (βCD), hydroxypropyl-β-cyclodextrin (HPβCD) with degrees of substitution of 0.63 and 0.87, randomly methylated β-cyclodextrin (Rameb ® ), sulfobutylether-β-cyclodextrin (Captisol ® ) and methyl-β-cyclodextrin (Crysmeb ® ). Rheology testing and mini extrusion using a conical twin screw mini extruder were performed to test the processability of the different CD mixtures since CD are not thermoplastic. This allowed Captisol ® and Crysmeb ® to be discarded from the study due to their high impact on the viscosity of the SOL/ITZ mixture. The remaining CD were processed by HME in an 18mm twin screw extruder. Saturation concentration measurements confirmed the enhancement of solubility of ITZ for the four CD formulations. Biphasic dissolution tests indicated that all four formulations had faster release profiles compared to the SOL/ITZ solid dispersion. Formulations of HPβCD 0.63 and Rameb ® even reached 95% of ITZ released in both phases after 1h. The formulations were characterized using thermal differential scanning calorimetry and attenuated total reflectance infra-red analysis. These analyses confirmed that the increased release profile was due to the formation of ternary inclusion complexes. Copyright © 2016 Elsevier B.V. All rights reserved.

Melt extrusion vs. spray drying: The effect of processing methods on crystalline content of naproxen-povidone formulations.

PubMed

Haser, Abbe; Cao, Tu; Lubach, Joe; Listro, Tony; Acquarulo, Larry; Zhang, Feng

2017-05-01

Our hypothesis is that melt extrusion is a more suitable processing method than spray drying to prepare amorphous solid dispersions of drugs with a high crystallization tendency. Naproxen-povidone K25 was used as the model system in this study. Naproxen-povidone K25 solid dispersions at 30% and 60% drug loadings were characterized by modulated DSC, powder X-ray diffraction, FT-IR, and solid-state 13 C NMR to identify phase separation and drug recrystallization during processing and storage. At 30% drug loading, hydrogen bond (H-bond) sites of povidone K25 were not saturated and the glass transition (T g ) temperature of the formulation was higher. As a result, both melt-extruded and spray-dried materials were amorphous initially and remained so after storage at 40°C. At 60% drug loading, H-bond sites were saturated, and T g was low. We were not able to prepare amorphous materials. The initial crystallinity of the formulations was 0.4%±0.2% and 5.6%±0.6%, and increased to 2.7%±0.3% and 21.6%±1.0% for melt-extruded and spray-dried materials, respectively. Spray-dried material was more susceptible to re-crystallization during processing, due to the high diffusivity of naproxen molecules in the formulation matrix and lack of kinetic stabilization from polymer solution. A larger number of crystalline nucleation sites and high surface area made the spray-dried material more susceptible to recrystallization during storage. This study demonstrated the unique advantages of melt extrusion over spray drying for the preparation of amorphous solid dispersions of naproxen at high drug level. Copyright © 2017 Elsevier B.V. All rights reserved.

Fabrication of seamless calandria tubes by cold pilgering route using 3-pass and 2-pass schedules

NASA Astrophysics Data System (ADS)

Saibaba, N.

2008-12-01

Calandria tube is a large diameter, extremely thin walled zirconium alloy tube which has diameter to wall thickness ratio as high as 90-95. Such tubes are conventionally produced by the 'welded route', which involves extrusion of slabs followed by a series of hot and cold rolling passes, intermediate anneals, press forming of sheets into circular shape and closing the gap by TIG welding. Though pilgering is a well established process for the fabrication of seamless tubes, production of extremely thin walled tubes offers several challenges during pilgering. Nuclear fuel complex (NFC), Hyderabad, has successfully developed a process for the production of Zircaloy-4 calandria tubes by adopting the 'seamless route' which involves hot extrusion of mother blanks followed by three-pass pilgering or two-pass pilgering schedules. This paper deals with standardization of the seamless route processes for fabrication of calandria tubes, comparison between the tubes produced by 2-pass and 3-pass pilgering schedules, role of ultrasonic test charts for control of process parameters, development of new testing methods for burst testing and other properties.

Modelling and simulation of dynamic recrystallization (DRX) in OFHC copper at very high strain rates

NASA Astrophysics Data System (ADS)

Testa, G.; Bonora, N.; Ruggiero, A.; Iannitti, G.; Persechino, I.; Hörnqvist, M.; Mortazavi, N.

2017-01-01

At high strain rates, deformation processes are essentially adiabatic and if the plastic work is large enough dynamic recrystallization can occur. In this work, an examination on microstructure evolution of OFHC copper in Dynamic Tensile Extrusion (DTE) test, performed at 400 m/s, was carried out. EBSD investigations, along the center line of the fragment remaining in the extrusion die, showed a progressive elongation of the grains, and an accompanying development of a strong <001> + <111> dual fiber texture. Discontinuous dynamic recrystallization (DRX) occurred at larger strains, and it was showed that nucleation occurred during straining. A criterion for DRX to occur, based on the evolution of Zener-Hollomon parameter during the dynamic deformation process, is proposed. Finally, DTE test was simulated using the modified Rusinek-Klepaczko constitutive model incorporating a model for the prediction of DRX initiation.

Advanced powder metallurgy aluminum alloys via rapid solidification technology

NASA Technical Reports Server (NTRS)

Ray, R.

1984-01-01

Aluminum alloys containing 10 to 11.5 wt. pct. of iron and 1.5 to 3 wt. pct. of chromium using the technique of rapid solidification powder metallurgy were studied. Alloys were prepared as thin ribbons (.002 inch thick) rapidly solidified at uniform rate of 10(6) C/second by the melt spinning process. The melt spun ribbons were pulverized into powders (-60 to 400 mesh) by a rotating hammer mill. The powders were consolidated by hot extrusion at a high reduction ratio of 50:1. The powder extrusion temperature was varied to determine the range of desirable processing conditions necessary to yield useful properties. Powders and consolidated alloys were characterized by SEM and optical metallography. The consolidated alloys were evaluated for (1) thermal stability, (2) tensile properties in the range, room temperature to 450 F, and (3) notch toughness in the range, room temperature to 450 F.

High-throughput method to predict extrusion pressure of ceramic pastes.

PubMed

Cao, Kevin; Liu, Yang; Tucker, Christopher; Baumann, Michael; Grit, Grote; Lakso, Steven

2014-04-14

A new method was developed to measure the rheology of extrudable ceramic pastes using a Hamilton MicroLab Star liquid handler. The Hamilton instrument, normally used for high throughput liquid processing, was expanded to function as a low pressure capillary rheometer. Diluted ceramic pastes were forced through the modified pipettes, which produced pressure drop data that was converted to standard rheology data. A known ceramic paste containing cellulose ether was made and diluted to various concentrations in water. The most dilute paste samples were tested in the Hamilton instrument and the more typical, highly concentrated, ceramic paste were tested with a hydraulic ram extruder fitted with a capillary die and pressure measurement system. The rheology data from this study indicates that the dilute high throughput method using the Hamilton instrument correlates to, and can predict, the rheology of concentrated ceramic pastes normally used in ceramic extrusion production processes.

Development of dispersion strengthened nickel-chromium alloy (Ni-Cr-ThO2) sheet for space shuttle vehicles, part 2

NASA Technical Reports Server (NTRS)

Klingler, L. J.; Weinberger, W. R.; Bailey, P. G.; Baranow, S.

1972-01-01

Two dispersion strengthened nickel base alloy systems were developed for use at temperatures up to 1204 C(2200 F); TD nickel chromium (TDNiCr) and TD nickel chromium aluminum (TDNiCrA1). They are considered candidate materials for use on the thermal protection systems of the space shuttle and for long term use in aircraft gas turbine engine applications. Improved manufacturing processes were developed for the fabrication of TDNiCr sheet and foil to specifications. Sheet rolling process studies and extrusion studies were made on two aluminum containing alloys: Ni-16%Cr-3.5%A1-2%ThO2 and Ni-16%Cr-5.0%A12%ThO2. Over 1600 kg.(3500 lb.) of plate, sheet, foil, bar and extrusion products were supplied to NASA Centers for technology studies.

Effects of selected process parameters in extrusion of yam flour (Dioscorea rotundata) on physicochemical properties of the extrudates.

PubMed

Sebio, L; Chang, Y K

2000-04-01

Raw yam (Dioscorea rotundata) flour was cooked and extruded in a Brabender single-screw laboratory scale extruder. Response surface methodology using an incomplete factorial design was applied with various combinations of barrel temperature [100, 125, 150 degrees C], feed moisture content [18, 22, 26%] and screw speed [100, 150, 200 rpm]. Initial viscosity at 30 degrees C, water solubility index, expansion and hardness were determined. The highest values of initial viscosity were at the highest barrel temperatures and the highest moisture contents. At high feed moisture content and high barrel temperatures the yam extrudate flour showed the greatest values of water solubility index. The physical properties of the extruded product showed that at high temperature the lower the moisture content the greater the expansion index. Hardness was influenced directly by moisture content and inversely by extrusion temperature. The extrusion of yam flour led to the production of snacks and pre-gelatinized flours of diverse properties. Also extruded yam flour can be successfully used in the preparation of 'futu' (pre-cooked compact dough), a yam-based food, popular in Western Africa.

Mechanical and degradation property improvement in a biocompatible Mg-Ca-Sr alloy by thermomechanical processing

DOE PAGES

Henderson, Hunter B.; Ramaswamy, Vidhya; Wilson-Heid, Alexander E.; ...

2018-02-03

Magnesium-based alloys have attracted interest as a potential material to comprise biomedical implants that are simultaneously high-strength and temporary, able to provide stabilization before degrading safely and able to be excreted by the human body. Many alloy systems have been evaluated, but this work reports on improved properties through hot extrusion of one promising alloy: Mg-1.0 wt% Ca-0.5 wt%Sr. This alloy has previously demonstrated promising toxicity and degradation properties in the as-cast and rolled conditions. In the current study extrusion causes a dramatic improvement in the mechanical properties in tension and compression, as well as a low in vitro degradationmore » rate. Microstructure (texture, second phase distribution, and grain size), bulk mechanical properties, flow behavior, degradation in simulated body fluid, and effect on osteoblast cyctotoxicity are evaluated and correlated to extrusion temperature. In conclusion, maximum yield strength of 300 MPa (above that of annealed 316 stainless steel) with 10% elongation is observed, making this alloy competitive with existing implant materials.« less

Mechanical and degradation property improvement in a biocompatible Mg-Ca-Sr alloy by thermomechanical processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henderson, Hunter B.; Ramaswamy, Vidhya; Wilson-Heid, Alexander E.

Magnesium-based alloys have attracted interest as a potential material to comprise biomedical implants that are simultaneously high-strength and temporary, able to provide stabilization before degrading safely and able to be excreted by the human body. Many alloy systems have been evaluated, but this work reports on improved properties through hot extrusion of one promising alloy: Mg-1.0 wt% Ca-0.5 wt%Sr. This alloy has previously demonstrated promising toxicity and degradation properties in the as-cast and rolled conditions. In the current study extrusion causes a dramatic improvement in the mechanical properties in tension and compression, as well as a low in vitro degradationmore » rate. Microstructure (texture, second phase distribution, and grain size), bulk mechanical properties, flow behavior, degradation in simulated body fluid, and effect on osteoblast cyctotoxicity are evaluated and correlated to extrusion temperature. In conclusion, maximum yield strength of 300 MPa (above that of annealed 316 stainless steel) with 10% elongation is observed, making this alloy competitive with existing implant materials.« less

Mechanical and degradation property improvement in a biocompatible Mg-Ca-Sr alloy by thermomechanical processing.

PubMed

Henderson, Hunter B; Ramaswamy, Vidhya; Wilson-Heid, Alexander E; Kesler, Michael S; Allen, Josephine B; Manuel, Michele V

2018-04-01

Magnesium-based alloys have attracted interest as a potential material to comprise biomedical implants that are simultaneously high-strength and temporary, able to provide stabilization before degrading safely and able to be excreted by the human body. Many alloy systems have been evaluated, but this work reports on improved properties through hot extrusion of one promising alloy: Mg-1.0 wt% Ca-0.5 wt%Sr. This alloy has previously demonstrated promising toxicity and degradation properties in the as-cast and rolled conditions. In the current study extrusion causes a dramatic improvement in the mechanical properties in tension and compression, as well as a low in vitro degradation rate. Microstructure (texture, second phase distribution, and grain size), bulk mechanical properties, flow behavior, degradation in simulated body fluid, and effect on osteoblast cyctotoxicity are evaluated and correlated to extrusion temperature. Maximum yield strength of 300 MPa (above that of annealed 316 stainless steel) with 10% elongation is observed, making this alloy competitive with existing implant materials. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Remodeling of adhesion and modulation of mechanical tensile forces during apoptosis in Drosophila epithelium.

PubMed

Teng, Xiang; Qin, Lei; Le Borgne, Roland; Toyama, Yusuke

2017-01-01

Apoptosis is a mechanism of eliminating damaged or unnecessary cells during development and tissue homeostasis. During apoptosis within a tissue, the adhesions between dying and neighboring non-dying cells need to be remodeled so that the apoptotic cell is expelled. In parallel, contraction of actomyosin cables formed in apoptotic and neighboring cells drives cell extrusion. To date, the coordination between the dynamics of cell adhesion and the progressive changes in tissue tension around an apoptotic cell is not fully understood. Live imaging of histoblast expansion, which is a coordinated tissue replacement process during Drosophila metamorphosis, shows remodeling of adherens junctions (AJs) between apoptotic and non-dying cells, with a reduction in the levels of AJ components, including E-cadherin. Concurrently, surrounding tissue tension is transiently released. Contraction of a supra-cellular actomyosin cable, which forms in neighboring cells, brings neighboring cells together and further reshapes tissue tension toward the completion of extrusion. We propose a model in which modulation of tissue tension represents a mechanism of apoptotic cell extrusion. © 2017. Published by The Company of Biologists Ltd.

Embedded Multimaterial Extrusion Bioprinting.

PubMed

Rocca, Marco; Fragasso, Alessio; Liu, Wanjun; Heinrich, Marcel A; Zhang, Yu Shrike

2018-04-01

Embedded extrusion bioprinting allows for the generation of complex structures that otherwise cannot be achieved with conventional layer-by-layer deposition from the bottom, by overcoming the limits imposed by gravitational force. By taking advantage of a hydrogel bath, serving as a sacrificial printing environment, it is feasible to extrude a bioink in freeform until the entire structure is deposited and crosslinked. The bioprinted structure can be subsequently released from the supporting hydrogel and used for further applications. Combining this advanced three-dimensional (3D) bioprinting technique with a multimaterial extrusion printhead setup enables the fabrication of complex volumetric structures built from multiple bioinks. The work described in this paper focuses on the optimization of the experimental setup and proposes a workflow to automate the bioprinting process, resulting in a fast and efficient conversion of a virtual 3D model into a physical, extruded structure in freeform using the multimaterial embedded bioprinting system. It is anticipated that further development of this technology will likely lead to widespread applications in areas such as tissue engineering, pharmaceutical testing, and organs-on-chips.

Phenomenological model of maize starches expansion by extrusion

NASA Astrophysics Data System (ADS)

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.

Characterization of weathered wood-plastic composite surfaces using FTIR spectroscopy, contact angle, and XPS

Treesearch

Nicole M. Stark; Laurent M. Matuana

2007-01-01

Much of the current growth of wood-plastic composites (WPCs) is due to increased penetration into the decking market; therefore it has become imperative to understand the durability of WPCs in outdoor applications. In this study, wood flour filled high-density polyethylene (HDPE) composites were manufactured through either injection molding or extrusion. A set of...

Identification of potent odorants formed during the preparation of extruded potato snacks.

PubMed

Majcher, Małgorzata A; Jeleń, Henryk H

2005-08-10

Extrusion cooking processing followed by air-drying has been applied to obtain low-fat potato snacks. Optimal parameters were developed for a dough recipe. Dough contained apart from potato granules 7% of canola oil, 1% of salt, 1% of baking powder, 5% of maltodextrin, and 15% of wheat flour. After the extrusion process, snacks were dried at 85 degrees C for 15 min followed by 130 degrees C for 45 min. The potent odorants of extruded potato snacks were identified using aroma extract dilution analysis and gas chromatography-olfactometry. Among the characteristic compounds, methional with boiled potato flavor, benzenemethanethiol with pepper-seed flavor, 2-acetyl-1-pyrroline with popcorn flavor, benzacetaldehyde with strong flowery flavor, butanal with rancid flavor, and 2-acetylpyrazine with roasty flavor were considered to be the main contributors to the aroma of extruded potato snacks. Several compounds were concluded to be developed during extrusion cooking, such as ethanol, 3-methylbutanal, (Z)-1,5-octadien-3-one with geranium flavor, and unknown ones with the flavor of boiled potato, cumin, candy, or parsley root. Compounds such as methanethiol, 2,3-pentanedione, limonene, 2-acetylpyrazine, 2-ethyl-3,5-dimethylpyrazine, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, 2-methyl-3,5-diethylpyrazine, 5-methyl-2,3-diethylpyrazine, and (E)-beta-damascenone were probably developed during air-drying of the potato extrudate.

Development of functional extruded snacks by utilizing paste shrimp (Acetes spp.): process optimization and quality evaluation.

PubMed

Kumar, Raushan; Xavier, Ka Martin; Lekshmi, Manjusha; Dhanabalan, Vignaesh; Thachil, Madonna T; Balange, Amjad K; Gudipati, Venkateshwarlu

2018-04-01

Functional extruded snacks were prepared using paste shrimp powder (Acetes spp.), which is rich in protein. The process variables required for the preparation of extruded snacks was optimized using response surface methodology. Extrusion temperature (130-144 °C), level of Acetes powder (100-200 g kg -1 ) and feed moisture (140-200 g kg -1 ) were selected as design variables, and expansion ratio, porosity, hardness, crispness and thiobarbituric acid reactive substance value were taken as the response variables. Extrusion temperature significantly influenced all the response variables, while Acetes inclusion influenced all variables except porosity. Feed moisture content showed a significant quadratic effect on all responses and an interactive effect on expansion ratio and hardness. Shrimp powder incorporation increased the protein and mineral content of the final product. The extruded snack made with the combination of extrusion temperature 144.59 °C, feed moisture 178.5 g kg -1 and Acetes inclusion level 146.7 g kg -1 was found to be the best one based on sensory evaluation. The study suggests that use of Acetes species for the development of extruded snacks will serve as a means of utilization of Acetes as well as being a rich source of proteins for human consumption, which would otherwise remain unexploited as a by-catch. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Optimization of Extrusion Process of Directly Expanded Snacks Based on Potato Starch in a Single Step for the Formation of Type IV Resistant Starch.

PubMed

Calvo-López, Amira Daniela; Martínez-Bustos, Fernando

2017-09-01

Resistant starch type IV (RSIV) can be produced by chemical modifications (etherized or esterified) such as conversion, substitution, or cross-linking, which can prevent its digestion by blocking enzyme access and forming atypical linkages. In this research, the effects of barrel temperature (145.86-174.14 °C), the screw speed (42.93-57.07 Hz) and derivatization (esterification) in the formation of RSIV content of directly expanded snacks (second generation snacks) were studied. Potato starch was chemically modified by phosphorylation and succinylation, and expanded by using the extrusion cooking process. Snacks with phosphorylated starch showed expansion index from 2.57 to 3.23, bulk density from 306.19 to 479.00 kg/m 3 and RSIV from 43.27 to 55.81%. Snacks with succinylated starch had expansion index from 3.52 to 3.82, bulk density from 99.85 to 134.51 kg/m 3 and RSIV from 23.17 to 35.01%. The results found in this work showed that it is possible to manufacture extruded directly expanded snacks (second-generation snacks) such as a ready-to-eat (RTE) with good physicochemical properties and without substantial loss of extrusion functionality, which could bring a healthy benefit due to the presence of RSIV.

Influence of processing on the microstructure and mechanical properties of 14YWT

DOE PAGES

Hoelzer, David T.; Unocic, Kinga A.; Sokolov, Mikhail A.; ...

2015-12-15

In this study, the investigation of the mechanical alloying (MA) conditions for producing the advanced oxide dispersion strengthened (ODS) 14YWT ferritic alloy led to significant improvements in balancing the strength, ductility and fracture toughness properties while still maintaining the salient microstructural features consisting of ultra-fine grains and high concentration of Y-, Ti- and O-enriched nanoclusters. The implemented changes to the processing conditions included reducing the contamination of the powder during ball milling, applying a pre-extrusion annealing treatment on the ball milled powder and exploring different extrusion temperatures at 850 °C (SM170 heat), 1000 °C (SM185) and 1150 °C (SM200). Themore » microstructural studies of the three 14YWT heats showed similarities in the dispersion of nanoclusters and sub-micron size grains, indicating the microstructure was insensitive to the different extrusion conditions. Compared to past 14YWT heats, the three new heats showed lower strength, but higher ductility levels between 25 and 800 °C and significantly higher fracture toughness values between 25 °C and 700 °C. The lower contamination levels of O, C and N achieved with improved ball milling conditions plus the slightly larger grain size were identified as important factors for improving the balance in mechanical properties of the three heats of 14YWT.« less

Physico-chemical, nutritional and infrared spectroscopy evaluation of an optimized soybean/corn flour extrudate.

PubMed

Guzmán-Ortiz, Fabiola Araceli; Hernández-Sánchez, Humberto; Yee-Madeira, Hernani; San Martín-Martínez, Eduardo; Robles-Ramírez, María Del Carmen; Rojas-López, Marlon; Berríos, Jose De J; Mora-Escobedo, Rosalva

2015-07-01

A central composite design using RMS (Response Surface Methodology) successfully described the effect of independent variables (feed moisture, die temperature and soybean proportion) on the specific parameters of product quality as expansion index (EI), water absorption index (WAI), water solubility index (WSI) and total color difference (ΔE) studied. The regression model indicated that EI, WAI, WSI and ΔE were significant (p < 0.05) with coefficients of determination (R(2)) of 0.7371, 0.7588, 0.7622, 0.8150, respectively. The optimized processing conditions were obtained with 25.8 % feed moisture, 160 °C die temperature and 58 %/42 % soybean/corn proportion. It was not found statistically changes in amino acid profile due to extrusion process. The electrophoretic profile of extruded soybean/corn mix presented low intensity molecular weight bands, compared to the unprocessed sample. The generation of low molecular weight polypeptides was associated to an increased in In vitro protein digestibility (IVPD) of the extrudate. The FTIR spectra of the soybean/corn mix before and after extrusion showed that the α-helix structure remained unchanged after extrusion. However, the band associated with β-sheet structure showed to be split into two bands at 1624 and 1640 cm(-1) . The changes in the β-sheet structures may be also associated to the increased in IVPD in the extruded sample.

Mechanochemical Synthesis of Pharmaceutical Cocrystal Suspensions via Hot Melt Extrusion: Feasibility Studies and Physicochemical Characterization.

PubMed

Li, Shu; Yu, Tao; Tian, Yiwei; McCoy, Colin P; Jones, David S; Andrews, Gavin P

2016-09-06

Engineered cocrystals offer an alternative solid drug form with tailored physicochemical properties. Interestingly, although cocrystals provide many new possibilities, they also present new challenges, particularly in regard to their design and large-scale manufacture. Current literature has primarily focused on the preparation and characterization of novel cocrystals typically containing only the drug and coformer, leaving the subsequent formulation less explored. In this paper we propose, for the first time, the use of hot melt extrusion for the mechanochemical synthesis of pharmaceutical cocrystals in the presence of a meltable binder. In this approach, we examine excipients that are amenable to hot melt extrusion, forming a suspension of cocrystal particulates embedded in a pharmaceutical matrix. Using ibuprofen and isonicotinamide as a model cocrystal reagent pair, formulations extruded with a small molecular matrix carrier (xylitol) were examined to be intimate mixtures wherein the newly formed cocrystal particulates were physically suspended in a matrix. With respect to formulations extruded using polymeric carriers (Soluplus and Eudragit EPO, respectively), however, there was no evidence within PXRD patterns of either crystalline ibuprofen or the cocrystal. Importantly, it was established in this study that an appropriate carrier for a cocrystal reagent pair during HME processing should satisfy certain criteria including limited interaction with parent reagents and cocrystal product, processing temperature sufficiently lower than the onset of cocrystal Tm, low melt viscosity, and rapid solidification upon cooling.

Inline UV/Vis spectroscopy as PAT tool for hot-melt extrusion.

PubMed

Wesholowski, Jens; Prill, Sebastian; Berghaus, Andreas; Thommes, Markus

2018-01-11

Hot-melt extrusion on co-rotating twin screw extruders is a focused technology for the production of pharmaceuticals in the context of Quality by Design. Since it is a continuous process, the potential for minimizing product quality fluctuation is enhanced. A typical application of hot-melt extrusion is the production of solid dispersions, where an active pharmaceutical ingredient (API) is distributed within a polymer matrix carrier. For this dosage form, the product quality is related amongst others to the drug content. This can be monitored on- or inline as critical quality attribute by a process analytical technology (PAT) in order to meet the specific requirements of Quality by Design. In this study, an inline UV/Vis spectrometer from ColVisTec was implemented in an early development twin screw extruder and the performance tested in accordance to the ICH Q2 guideline. Therefore, two API (carbamazepine and theophylline) and one polymer matrix (copovidone) were considered with the main focus on the quantification of the drug load. The obtained results revealed the suitability of the implemented PAT tool to quantify the drug load in a typical range for pharmaceutical applications. The effort for data evaluation was minimal due to univariate data analysis, and in combination with a measurement frequency of 1 Hz, the system is sufficient for real-time data acquisition.

Analyzing the extrusion mould for aluminum profile

NASA Astrophysics Data System (ADS)

Yun, Wang; Xu, Zhenying; Dai, Yachun; Dong, Peilong; Yuan, Guoding; Lan, Cai

2007-12-01

The die or mould used for extruding aluminum wallboard profile is in serious work conditions, so it is easy to appear drawbacks in the mould such as non-uniform stress and strain distributions, crack initiation and propagation, elastic warp, and even plastic distortion. As we know, the extrusion die or mould is subject to complex loads including the extrusion pressure, friction and thermal load, which make the mould complicated and hard to be designed and analyzed by using conventional analytical method. In this paper, we applied Deform-3D, FEA (Finite Element Analysis) software used frequently in all engineering fields, to simulate three-dimensional extruding process of aluminum profile. The simulation results show that the deformation increases gradually from inside to outside. Exterior deformation contour distribution is relative uniform since the influence of inner holes on deformation is small, and the contour form is regular and similar with the shape of the mould. However, the interior deformation contour is irregular as the influence of holes with basically symmetric equivalent curves. At the middle of the mould, the deformation reaches the largest, it reaches 0.633mm. The deformation of the mould can be reduced by increasing the distance between two holes or increasing thickness of the mould. Experiment result accords with simulation. The simulation process and results ensure the feasibility of finite element method, providing the support for mould design and structural optimization.

Reprint of: Effects of cold deformation, electron irradiation and extrusion on deuterium desorption behavior in Zr-1%Nb alloy

NASA Astrophysics Data System (ADS)

Morozov, O.; Mats, O.; Mats, V.; Zhurba, V.; Khaimovich, P.

2018-01-01

The present article introduces the data of analysis of ranges of ion-implanted deuterium desorption from Zr-1% Nb alloy. The samples studied underwent plastic deformation, low temperature extrusion and electron irradiation. Plastic rolling of the samples at temperature ∼300 K resulted in plastic deformation with the degree of ε = 3.9 and the formation of nanostructural state with the average grain size of d = 61 nm. The high degree of defectiveness is shown in thermodesorption spectrum as an additional area of the deuterium desorption in the temperature ranges 650-850 K. The further processing of the sample (that had undergone plastic deformation by plastic rolling) with electron irradiation resulted in the reduction of the average grain size (58 nm) and an increase in borders concentration. As a result the amount of deuterium desorpted increased in the temperature ranges 650-900 K. In case of Zr-1% Nb samples deformed by extrusion the extension of desorption area is observed towards the temperature reduction down to 420 K. The formation of the phase state of deuterium solid solution in zirconium was not observed. The structural state behavior is a control factor in the process of deuterium thermodesorption spectrum structure formation with a fixed implanted deuterium dose (hydrogen diagnostics). It appears as additional temperature ranges of deuterium desorption depending on the type, character and defect content.

PVC extrusion development and production for the NOvA neutrino experiment

DOE PAGES

Talaga, R. L.; Grudzinski, J. J.; Phan-Budd, S.; ...

2017-03-08

We have produced large and highly-reflective open-cell PVC extrusions for the NOvA neutrino oscillation experiment. The extrusions were sealed, instrumented, assembled into self-supporting detector blocks, and filled with liquid scintillator. Each Far Detector block stands 15.7 m high, is 15.7 m wide and 2.1 m thick. More than 22,000 extrusions were produced with high dimensional tolerance and robust mechanical strength. This paper provides an overview of the NOvA Far Detector, describes the preparation of the custom PVC powder, and the making of the extrusions. As a result, quality control was a key element in the production and is described inmore » detail.« less

Method for extruding pitch based foam

DOEpatents

Klett, James W.

2002-01-01

A method and apparatus for extruding pitch based foam is disclosed. The method includes the steps of: forming a viscous pitch foam; passing the precursor through an extrusion tube; and subjecting the precursor in said extrusion tube to a temperature gradient which varies along the length of the extrusion tube to form an extruded carbon foam. The apparatus includes an extrusion tube having a passageway communicatively connected to a chamber in which a viscous pitch foam formed in the chamber paring through the extrusion tube, and a heating mechanism in thermal communication with the tube for heating the viscous pitch foam along the length of the tube in accordance with a predetermined temperature gradient.

Reducing the Surface Degradation of Aluminum Extrusion Dies During Preheating

NASA Astrophysics Data System (ADS)

Stratton, Paul

2010-07-01

Aluminum extrusion dies are usually made from H13 steel that is ferritically nitrocarburized to minimize wear and pick-up. Before being placed in the extrusion press, the dies are preheated to minimize thermal shock at the start of the extrusion cycle. During the preheating time, the nitrocarburized layer oxidizes. Some of this layer can break away during extrusion leaving marks on the product. Although inerting the preheat furnaces with nitrogen has been found to reduce the oxidation, it does not solve the problem completely. Experiments have shown that a small addition of ammonia to the preheating protective atmosphere could eliminate oxidation and prevent nitrogen loss from the surface nitride layer.

Thermal and Kinetic Modelling of Elastomer Flow—Application to an Extrusion Die

NASA Astrophysics Data System (ADS)

Launay, J.; Allanic, N.; Mousseau, P.; Deterre, R.

2011-05-01

This paper reports and discusses the thermal and kinetic behaviour of elastomer flow inside an extrusion die. The reaction progress through the runner was modeled by using a particle tracking technique. The aim is to analyze viscous dissipation phenomena to control scorch arisen, improve the rubber compound curing homogeneity and reduce the heating time in the mould using the progress of the induction time. The heat and momentum equations were solved in three dimensions with Ansys Polyflow. A particle tracking technique was set up to calculate the reaction progress. Several simulations were performed to highlight the influence of process parameters and geometry modifications on the rubber compound thermal and cure homogeneity.

Evolution of microstructure and precipitates in 2xxx aluminum alloy after severe plastic deformation

NASA Astrophysics Data System (ADS)

Adamczyk-Cieslak, B.; Zdunek, J.; Mizera, J.

2016-04-01

This paper investigates the influence of precipitation on the microstructure development in a 2xxx aluminum alloy subjected to hydrostatic extrusion. A three step reduction of the diameter was performed using hydrostatic extrusion (HE) process: from 20mm (initial state) to 10 mm, 5 mm and 3 mm, which corresponds to the logarithmic deformations ɛ = 1.4, ɛ = 2.8 and ɛ = 3.8 respectively. The microstructure and precipitation analysis before and after deformation was performed using transmission electron microscope (TEM), and scanning electron microscopy (SEM). As a result of the tests, a very significant influence of precipitation on the degree of refinement and mechanism of microstructure transformation was stated.

Improved Tubulars for Better Economics in Deep Gas Well Drilling using Microwave Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dinesh Agrawal; Paul Gigl; Mahlon Dennis

2006-02-01

The objective of the research program has been to improve the rate-of-penetration in deep hostile environments by improving the life cycle and performance of coiled-tubing, an important component of a deep well drilling system for oil and gas exploration. The current process of the manufacture long tubular steel products consists of shaping the tube from flat strip, welding the seam and sections into lengths that can be miles long, and coiling onto reels. However, the welds, that are a weak point, now limit the performance of the coil tubing. This is not only from a toughness standpoint but also frommore » a corrosion standpoint. By utilizing the latest developments in the sintering of materials with microwave energy and powder metal extrusion technology for the manufacture of seamless coiled tubing and other tubular products, these problems can be eliminated. The project is therefore to develop a continuous microwave process to sinter continuously steel tubulars and butt-join them using microwave/induction process. The program started about three years ago and now we are in the middle of Phase II. In Phase I (which ended in February 2005) a feasibility study of the extrusion process of steel powder and continuously sinter the extruded tubing was conducted. The research program has been based on the development of microwave technology to process tubular specimens of powder metals, especially steels. The existing microwave systems at the Materials Research Laboratory (MRL) and Dennis Tool Company (DTC) were suitably modified to process tubular small specimens. The precursor powder metals were either extruded or cold isostatically pressed (CIP) to form tubular specimens. After conducting an extensive and systematic investigation of extrusion process for producing long tubes, it was determined that there were several difficulties in adopting extrusion process and it cannot be economically used for producing thousands of feet long green tubing. Therefore, in the Phase II the approach was modified to the microwave sintering combined with Cold Isostatic Press (CIP) and joining (by induction or microwave). This process can be developed into a semi-continuous sintering process if the CIP can produce parts fast enough to match the microwave sintering rates. This report summarizes the progress made to-date in this new approach. The final steel composition matching with the Quality tubing's QT-16Cr80 was short listed and used for all experiments. Bonding experiments using 4 different braze powders were conducted and the process optimized to obtain high degree of bonding strength. For fabrication of green tubulars a large CIP unit was acquired and tested. This equipment is located at the Dennis Tool facility in Houston. Microwave sintering experiments for continuous processing of the CIPed tubes are under progress in order to identify the optimum conditions. There have been some reproducibility problems and we are at present working to resolve these problems.« less

Design and optimization of disintegrating pellets of MCC by non-aqueous extrusion process using statistical tools.

PubMed

Gurram, Rajesh Kumar; Gandra, Suchithra; Shastri, Nalini R

2016-03-10

The objective of the study was to design and optimize a disintegrating pellet formulation of microcrystalline cellulose by non-aqueous extrusion process for a water sensitive drug using various statistical tools. Aspirin was used as a model drug. Disintegrating matrix pellets of aspirin using propylene glycol as a non-aqueous granulation liquid and croscarmellose as a disintegrant was developed. Plackett-Burman design was initially conducted to screen and identify the significant factors. Final optimization of formula was performed by response surface methodology using a central composite design. The critical attributes of the pellet dosage forms (dependent variables); disintegration time, sphericity and yield were predicted with adequate accuracy based on the regression model. Pareto charts and contour charts were studied to understand the influence of factors and predict the responses. A design space was constructed to meet the desirable targets of the responses in terms of disintegration time <5min, maximum yield, sphericity >0.95 and friability <1.7%. The optimized matrix pellets were enteric coated using Eudragit L 100. The drug release from the enteric coated pellets after 30min in the basic media was ~93% when compared to ~77% from the marketed pellets. The delayed release pellets stored at 25°C/60% RH were stable for a period of 10mo. In conclusion, it can be stated that the developed process for disintegrating pellets using non-aqueous granulating agents can be used as an alternative technique for various water sensitive drugs, circumventing the application of volatile organic solvents in conventional drug layering on inert cores. The scope of this study can be further extended to hydrophobic drugs, which may benefit from the rapid disintegration property and the use of various hydrophilic excipients used in the optimized pellet formulation to enhance dissolution and in turn improve bioavailability. Copyright © 2016 Elsevier B.V. All rights reserved.

Deficiencies in extrusion of the second polar body due to high calcium concentrations during in vitro fertilization in inbred C3H/He mice.

PubMed

Ohta, Yuki; Nagao, Yoshikazu; Minami, Naojiro; Tsukamoto, Satoshi; Kito, Seiji

2016-08-01

Successful in vitro fertilization (IVF) of all inbred strains of laboratory mice has not yet been accomplished. We have previously shown that a high calcium concentration improved IVF in various inbred mice. However, we also found that in cumulus-free ova of C3H/He mice such IVF conditions significantly increased the deficiency of extrusion of the second polar body (PBII) in a dose-dependent manner (2% at 1.71 mM and 29% at 6.84 mM, P < 0.05) and that PBII extrusion was affected by high calcium levels at 2-3 h post-insemination. While developmental competence of ova without PBII extrusion to blastocysts after 96 h culture was not affected, a significant reduction in the nuclear number of the inner cell mass was observed in blastocyst fertilized under high calcium condition. We also examined how high calcium concentration during IVF affects PBII extrusion in C3H/He mice. Cumulus cells cultured under high calcium conditions showed a significantly alleviated deficient PBII extrusion. This phenomenon is likely to be specific to C3H/He ova because deficient PBII extrusion in reciprocal fertilization between C3H and BDF1 gametes was observed only in C3H/He ova. Sperm factor(s) was still involved in deficient PBII extrusion due to high calcium concentrations, as this phenomenon was not observed in ova activated by ethanol. The cytoskeletal organization of ova without PBII extrusion showed disturbed spindle rotation, incomplete formation of contractile ring and disturbed localization of actin, suggesting that high calcium levels affect the anchoring machinery of the meiotic spindle. These results indicate that in C3H/He mice high calcium levels induce abnormal fertilization, i.e. deficient PBII extrusion by affecting the cytoskeletal organization, resulting in disturbed cytokinesis during the second meiotic division. Thus, use of high calcium media for IVF should be avoided for this strain.

Corporate Energy Conservation Program for Alcoa North American Extrusions

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2001-08-01

This case study is the latest in a series on industrial firms who are implementing energy efficient technologies and system improvements into their manufacturing processes. The case studies document the activities, savings, and lessons learned on these projects.

The Pliocene seamount series of La Palma/Canary Islands

NASA Astrophysics Data System (ADS)

Staudigel, Hubert; Schmincke, Hans-Ulrich

1984-12-01

A Pliocene submarine series of alkali basaltic pillow lavas, hyaloclastites, and breccias (A), a sheeted dike swarm (B), and a basal suite of gabbro and ultramafic rocks (C) from La Palma (Canary Islands) is interpreted as a cross section through an uplifted seamount. This series has been tilted to its present orientation of 50°/230° (plunge and azimuth), probably by upwarping due to intrusions in the central portion of the island. The basal plutonic complex (C) also includes intrusives coeval with up to 2000 m of younger subaerial alkali basaltic lavas unconformably overlying the submarine series. The plutonic suite (C) is overlain abruptly by more than 1800 m of sills (B), 0.4-1 m thick on average, with minor screens of lavas and breccias. Extrusives (A) form a 1750 m thick sequence of pillow lavas, breccias, and hyaloclastites. The clastic rocks increase in abundance upward and are of four main types: (1) breccias, consisting of partly broken pillows, formed nearly in situ, (2) heterolithologic pillow fragment breccias, (3) hyaloclastites composed dominantly of highly vesicular lapilli and ash sized shards, the latter thought to have formed by near surface explosive eruptions and been subsequently transported downslope by mass flows, (2) and (3) being interpreted to have been resedimented, and (4) pillow scoria breccias from the upper 700 m of the extrusive section consisting of amoeboidal, highly vesicular "pillows" and lava stringers and local bombs, probably formed by cracking and "bleeding" of gas-rich expanding pillow lava and some shallow submarine/subaerial lava fountaining. The extrusive series is chemically and mineralogically crudely zoned, with the most differentiated rocks (metatrachytes and mugearites) at the base and most picritic lavas occurring near the top of the series. Subsequent to emplacement, the entire extrusive and intrusive series has been hydrothermally altered, the lower part to greenschist and the upper part to smectite—zeolite facies mineral assemblages. The La Palma succession, combined with evidence from surface studies of seamounts, suggests that seamounts are formed by intrusive and extrusive processes in approximately equal portions. The nature of eruptive clastic and depositional mechanisms changes drastically during growth of a seamount if the critical depth for major magmatic degassing is surpassed and especially if magmatic explosive processes can occur at very shallow water depth, the critical depth depending on magma and thus volatile composition. Changes in slopes of a seamount influence depositional processes. Based on these factors, at least three major depositional sites develop as a seamount grows: summit, flank, and apron facies. Nonexplosive, extrusive processes prevail in the Deep Water Stage, dominantly producing pillow lavas (75%). These consist of individual pillow volcanoes up to 200 m high, with large pillows near the base and decreasing pillow size toward the top of a volcano. Pillow breccias, and pillow fragment breccias comprise approximately 20% of this facies. The deep water flank and apron facies are characterized by debris flow deposits with possibjy rather dense matrix material. The Shallow Water (shoaling) Stage is reached when the seamount top reaches the critical depth for drastic increase in exsolution of magmatic volatiles, about 800 m for the alkali basaltic seamount of La Palma, resulting in formation of mainly clastic rocks (70%): in situ pillow rind breccias and scoriaceous amoeboidal breccias and pillows are formed in the summit regions of the seamount, by repeated expansion and leaking of frothy pillow lava possibly by lava fountaining. Resedimented, heterolithologic pillow fragment breccias, lapilli breccias, and hyaloclastites are deposited on the flanks and aprons of the seamount. Pillow lavas comprise < 30% of these deposits.

In-line monitoring of compaction properties on a rotary tablet press during tablet manufacturing of hot-melt extruded amorphous solid dispersions.

PubMed

Grymonpré, W; Verstraete, G; Van Bockstal, P J; Van Renterghem, J; Rombouts, P; De Beer, T; Remon, J P; Vervaet, C

2017-01-30

As the number of applications for polymers in pharmaceutical development is increasing, there is need for fundamental understanding on how such compounds behave during tableting. This research is focussed on the tableting behaviour of amorphous polymers, their solid dispersions and the impact of hot-melt extrusion on the compaction properties of these materials. Soluplus, Kollidon VA 64 and Eudragit EPO were selected as amorphous polymers since these are widely studied carriers for solid dispersions, while Celecoxib was chosen as BCS class II model drug. Neat polymers and physical mixtures (up to 35% drug load) were processed by hot-melt extrusion (HME), milled and sieved to obtain powders with comparable particle sizes as the neat polymer. A novel approach was used for in-line analysis of the compaction properties on a rotary tablet press (Modul P, GEA) using complementary sensors and software (CDAAS, GEA). By combining 'in-die' and 'out-of-die' techniques, it was possible to investigate in a comprehensive way the impact of HME on the tableting behaviour of amorphous polymers and their formulations. The formation of stable glassy solutions altered the formulations towards more fragmentary behaviour under compression which was beneficial for the tabletability. Principal component analysis (PCA) was applied to summarize the behaviour during compaction of the formulations, enabling the selection of Soluplus and Kollidon VA 64 as the most favourable polymers for compaction of glassy solutions. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of calcium (Ca(2+)) extrusion mechanisms on electrophysiological properties in a hypoglossal motoneuron: insight from a mathematical model.

PubMed

Horn, Kyle G; Solomon, Irene C

2014-01-01

Spike-frequency dynamics and spike shape can provide insight into the types of ion channels present in any given neuron and give a sense for the precise response any neuron may have to a given input stimulus. Motoneuron firing frequency over time is especially important due to its direct effect on motor output. Of particular interest is intracellular Ca(2+), which exerts a powerful influence on both firing properties over time and spike shape. In order to better understand the cellular mechanisms for the regulation of intracellular Ca(2+) and their effect on spiking behavior, we have modified a computational model of an HM to include a variety of Ca(2+) handling processes. For the current study, a series of HM models that include Ca(2+) pumps, Na(+)/Ca(2+) exchangers, and a generic exponential decay of excess Ca(2+) were generated. Simulations from these models indicate that although each extrusion mechanism exerts a similar effect on voltage, the firing properties change distinctly with the inclusion of additional Ca(2+)-related mechanisms: BK channels, Ca(2+) buffering, and diffusion of [Ca(2+)]i modeled via a linear diffusion partial differential equation. While an exponential decay of Ca(2+) seems to adequately capture short-term changes in firing frequency seen in biological data, internal diffusion of Ca(2+) appears to be necessary for capturing longer term frequency changes. © 2014 Elsevier B.V. All rights reserved.

Enhanced additive manufacturing with a reciprocating platen

DOEpatents

Lind, Randall F.; Blue, Craig A.; Love, Lonnie J.; Post, Brian K.; Lloyd, Peter D.

2018-02-06

An additive manufacturing extrusion head that includes a heated nozzle for accepting a feedstock and extruding the feedstock onto a substrate at a deposition plane, the nozzle having a longitudinal extrusion axis. A reciprocating platen surrounds the nozzle, the platen operable to reciprocate along the extrusion axis at or above the deposition plane as the nozzle extrudes feedstock onto the substrate; and wherein the platen flattens the extruded feedstock such that it does not protrude above the deposition plane as the extrusion head traverses over the substrate.

Unidirectional Movement of Cellulose Synthase Complexes in Arabidopsis Seed Coat Epidermal Cells Deposit Cellulose Involved in Mucilage Extrusion, Adherence, and Ray Formation1[OPEN

PubMed Central

Lam, Patricia; Young, Robin; DeBolt, Seth

2015-01-01

CELLULOSE SYNTHASE5 (CESA5) synthesizes cellulose necessary for seed mucilage adherence to seed coat epidermal cells of Arabidopsis (Arabidopsis thaliana). The involvement of additional CESA proteins in this process and details concerning the manner in which cellulose is deposited in the mucilage pocket are unknown. Here, we show that both CESA3 and CESA10 are highly expressed in this cell type at the time of mucilage synthesis and localize to the plasma membrane adjacent to the mucilage pocket. The isoxaben resistant1-1 and isoxaben resistant1-2 mutants affecting CESA3 show defects consistent with altered mucilage cellulose biosynthesis. CESA3 can interact with CESA5 in vitro, and green fluorescent protein-tagged CESA5, CESA3, and CESA10 proteins move in a linear, unidirectional fashion around the cytoplasmic column of the cell, parallel with the surface of the seed, in a pattern similar to that of cortical microtubules. Consistent with this movement, cytological evidence suggests that the mucilage is coiled around the columella and unwinds during mucilage extrusion to form a linear ray. Mutations in CESA5 and CESA3 affect the speed of mucilage extrusion and mucilage adherence. These findings imply that cellulose fibrils are synthesized in an ordered helical array around the columella, providing a distinct structure to the mucilage that is important for both mucilage extrusion and adherence. PMID:25926481

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.

PubMed

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. Copyright © 2014. Published by Elsevier B.V.

Evaluation of 4 Different Irrigating Systems for Apical Extrusion of Sodium Hypochlorite.

PubMed

Yost, Ross A; Bergeron, Brian E; Kirkpatrick, Timothy C; Roberts, Mark D; Roberts, Howard W; Himel, Van T; Sabey, Kent A

2015-09-01

The aim of this study was to evaluate NaOCl apical extrusion by using negative apical pressure (EndoVac), sonic agitation (EndoActivator), side-vented needle (Max-i-Probe), and photon induced photoacoustic streaming (PIPS 10 mJ and PIPS 20 mJ) laser irrigation in an in vitro gel model. Extracted mandibular and maxillary central incisors (n = 18) were prepared to size 35/.04 and 55/.04, respectively. Teeth were mounted in transparent containers with clear acrylic and suspended in a color-changing pH-sensitive gel, creating a closed system. By using a crossover design, each tooth was sequentially irrigated by using 6% NaOCl with each device following manufacturers' recommendations. Each tooth served as its own control. Pre-irrigation and post-irrigation buccal and proximal view photographs served to measure the longest distance of extrusion and were analyzed with ImageJ software. Mean results were analyzed by using Kruskal-Wallis and Dunn post hoc test (P < .05). There were no significant differences between EndoVac, EndoActivator, and the passive extrusion groups. The EndoVac and EndoActivator groups produced significantly less extrusion than PIPS irrigation. Max-i-Probe extrusion results were more variable than those of EndoActivator but had no significant difference. Across all irrigation systems, there were no significant differences with respect to apical preparation size. Under the in vitro conditions of this study, no difference was found between the 10 mJ and 20 mJ PIPS laser groups. EndoVac demonstrated significantly less potential for apical extrusion than PIPS and Max-i-Probe, whereas apical preparation size did not significantly affect extrusion of irrigant. The potential for apical extrusion of endodontic irrigants should be a consideration when selecting a system for final irrigation. Published by Elsevier Inc.

A Comparison of Apical Bacterial Extrusion in Manual, ProTaper Rotary, and One Shape Rotary Instrumentation Techniques.

PubMed

Mittal, Rakesh; Singla, Meenu G; Garg, Ashima; Dhawan, Anu

2015-12-01

Apical extrusion of irrigants and debris is an inherent limitation associated with cleaning and shaping of root canals and has been studied extensively because of its clinical relevance as a cause of flare-ups. Many factors affect the amount of extruded intracanal materials. The purpose of this study was to assess the bacterial extrusion by using manual, multiple-file continuous rotary system (ProTaper) and single-file continuous rotary system (One Shape). Forty-two human mandibular premolars were inoculated with Enterococcus faecalis by using a bacterial extrusion model. The teeth were divided into 3 experimental groups (n = 12) and 1 control group (n = 6). The root canals of experimental groups were instrumented according to the manufacturers' instructions by using manual technique, ProTaper rotary system, or One Shape rotary system. Sterilized saline was used as an irrigant, and bacterial extrusion was quantified as colony-forming units/milliliter. The results obtained were statistically analyzed by using one-way analysis of variance for intergroup comparison and post hoc Tukey test for pair-wise comparison. The level for accepting statistical significance was set at P < .05. All the instrumentation techniques resulted in bacterial extrusion, with manual step-back technique exhibiting significantly more bacterial extrusion than the engine-driven systems. Of the 2 engine-driven systems, ProTaper rotary extruded significantly more bacteria than One Shape rotary system (P < .05). The engine-driven nickel-titanium systems were associated with less apical extrusion. The instrument design may play a role in amount of extrusion. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Rheometry of polymer melts using processing machines

NASA Astrophysics Data System (ADS)

Friesenbichler, Walter; Neunhäuserer, Andreas; Duretek, Ivica

2016-08-01

The technology of slit-die rheometry came into practice in the early 1960s. This technique enables engineers to measure the pressure drop very precisely along the slit die. Furthermore, slit-die rheometry widens up the measurable shear rate range and it is possible to characterize rheological properties of complicated materials such as wall slipping PVCs and high-filled compounds like long fiber reinforced thermoplastics and PIM-Feedstocks. With the use of slit-die systems in polymer processing machines e.g., Rauwendaal extrusion rheometer, by-pass extrusion rheometer, injection molding machine rheometers, new possibilities regarding rheological characterization of thermoplastics and elastomers at processing conditions near to practice opened up. Special slit-die systems allow the examination of the pressure-dependent viscosity and the characterization of cross-linking elastomers because of melt preparation and reachable shear rates comparable to typical processing conditions. As a result of the viscous dissipation in shear and elongational flows, when performing rheological measurements for high-viscous elastomers, temperature-correction of the apparent values has to be made. This technique was refined over the last years at Montanuniversitaet. Nowadays it is possible to characterize all sorts of rheological complicated polymeric materials under process- relevant conditions with viscosity values fully temperature corrected.

Direct ink writing of 3D conductive polyaniline structures and rheological modelling

NASA Astrophysics Data System (ADS)

Holness, F. Benjamin; Price, Aaron D.

2018-01-01

The intractable nature of conjugated polymers (CP) leads to practical limitations in the fabrication of CP-based transducers having complex three-dimensional geometries. Conventional CP device fabrication processes have focused primarily on thin-film deposition techniques; this study explores novel additive manufacturing processes specifically developed for CP with the ultimate goal of increasing the functionality of CP sensors and actuators. Herein we employ automated polymer paste extrusion processes for the direct ink writing of 3D conductive polyaniline (PANI) structures. Realization of these structures was enabled through a modified fused filament fabrication delta robot equipped with an integrated polymer paste extruder to fabricate high-resolution 3D conductive PANI structures. The required processability of PANI was achieved by means of a counterion-induced thermal doping method. The effect of thermal doping on the PANI-DBSA paste by means of a constitutive relationship to describe the paste flow as a function of the thermal doping time is explored. This relationship is incorporated within a flow model to predict the extruded track width as a function of various process parameters including: print speed, gauge pressure, nozzle diameter, and pre-extrusion thermal doping time.

Effects of processing method and moisture history on laboratory fungal resistance of wood-HDPE composites.

Treesearch

Craig M. Clemons; Rebecca E. Ibach

2004-01-01

The purpose of this study was to clarify the effects of composite processing and moisture sorption on laboratory fungal resistance of wood-plastic composites. A 2-week water soaking or cyclic boiling-drying procedure was used to infuse moisture into composites made from high-density polyethylene filled with 50 percent wood flour and processed by extrusion, compression...

Welding and Weldability of AZ31B by Gas Tungsten Arc and Laser Beam Welding Processes

NASA Astrophysics Data System (ADS)

Lathabai, S.; Barton, K. J.; Harris, D.; Lloyd, P. G.; Viano, D. M.; McLean, A.

Welding will play an important role in the fabrication of modular lightweight structures based on magnesium alloy die castings, extrusion profiles and wrought products. Minimisation of rejection rates during fabrication requires that satisfactory weldability be established for a particular combination of materials and welding procedures. In this paper, we present the results of a study to quantify the weldability of wrought alloy AZ31B by gas tungsten arc (GTA) and laser beam (LB) welding processes. The susceptibility to weld metal solidification cracking was evaluated using the Circular Patch weldability test. Operating windows of welding parameters for crack-free and porosity-free GTA and LB welding were identified, based on which welding procedures were developed for sheet and plate AZ31B. The microstructure and mechanical properties of welded test plates were assessed, leading to a better understanding of microstructurat development and structure-property relationships in GTA and LB weldments in AZ31B.

Quality and utilization of food co-products and residues

NASA Astrophysics Data System (ADS)

Cooke, P.; Bao, G.; Broderick, C.; Fishman, M.; Liu, L.; Onwulata, C.

2010-06-01

Some agricultural industries generate large amounts of low value co-products/residues, including citrus peel, sugar beet pulp and whey protein from the production of orange juice, sugar and cheese commodities, respectively. National Program #306 of the USDA Agricultural Research Service aims to characterize and enhance quality and develop new processes and uses for value-added foods and bio-based products. In parallel projects, we applied scanning microscopies to examine the molecular organization of citrus pectin gels, covalent crosslinking to reduce debonding in sugar beet pulp-PLA composites and functional modification of whey protein through extrusion in order to evaluate new methods of processing and formulating new products. Also, qualitative attributes of fresh produce that could potentially guide germ line development and crop management were explored through fluorescence imaging: synthesis and accumulation of oleoresin in habanero peppers suggest a complicated mechanism of secretion that differs from the classical scheme. Integrated imaging appears to offer significant structural insights to help understand practical properties and features of important food co-products/residues.

75 FR 51243 - Aluminum Extrusions from the People's Republic of China: Postponement of Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-19

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-967] Aluminum Extrusions from the... Department of Commerce (``the Department'') initiated an antidumping duty investigation on Aluminum... Aluminum Extrusions from the People's Republic of China: Initiation of Antidumping Duty Investigation, 75...

76 FR 18521 - Aluminum Extrusions From the People's Republic of China: Final Affirmative Countervailing Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-04

... People's Republic of China: Final Affirmative Countervailing Duty Determination AGENCY: Import... producers and exporters of aluminum extrusions from the People's Republic of China (the PRC). For... Aluminum Extrusions From the People's Republic of China: Preliminary Affirmative Countervailing Duty...

Effect of banana flour, screw speed and temperature on extrusion behaviour of corn extrudates.

PubMed

Kaur, Amritpal; Kaur, Seeratpreet; Singh, Mrinal; Singh, Narpinder; Shevkani, Khetan; Singh, Baljit

2015-07-01

Effect of extrusion parameters (banana flour, screw speed, extrusion temperature) on extrusion behaviour of corn grit extrudates were studied. Second order quadratic equations for extrusion properties as function of banana flour (BF), screwspeed (SS) and extrusion temperature (ET) were computed. BF had predominant effect on the Hunter color (L*, a*, b*) parameters of the extrudates. Addition of BF resulted in corn extrudates with higher L* and lower a* and b* values. Higher ET resulted in dark colored extrudates with lower L* and a* value. Higher SS enhanced the lightness of the extrudates. Expansion of the extrudates increased with increase in the level of BF and ET. WAI of the extrudates decreased with BF whereas increased with SS. However, reversed effect of BF and SS on WSI was observed. Flextural strength of the extrudates increased with increase in SS followed by BF and ET. The addition of BF and higher ET resulted in extrudates with higher oil uptake.

Development of a novel cold forging process to manufacture eccentric shafts

NASA Astrophysics Data System (ADS)

Pasler, Lukas; Liewald, Mathias

2018-05-01

Since the commercial usage of compact combustion engines, eccentric shafts have been used to transform translational into rotational motion. Over the years, several processes to manufacture these eccentric shafts or crankshafts have been developed. Especially for single-cylinder engines manufactured in small quantities, built crankshafts disclose advantages regarding tooling costs and performance. Those manufacturing processes do have one thing in common: They are all executed at elevated temperatures to enable the material to be formed to high forming degree. In this paper, a newly developed cold forging process is presented, which combines lateral extrusion and shifting for manufacturing a crank in one forming operation at room temperature. In comparison to the established upsetting and shifting methods to manufacture such components, the tool cavity or crank web thickness remains constant. Therefore, the developed new process presented in this paper consists of a combination of shifting and extrusion of the billet, which allows pushing material into the forming zone during shifting. In order to reduce the tensile stresses induced by the shifting process, compressive stresses are superimposed. It is expected that the process limits will be expanded regarding the horizontal displacement and form filling. In the following report, the simulation and design of the tooling concept are presented. Experiments were conducted and compared with corresponding simulation results afterwards.

76 FR 29007 - Certain Aluminum Extrusions From China

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-19

... Aluminum Extrusions From China Determinations On the basis of the record \\1\\ developed in the subject...), that an industry in the United States is materially injured by reason of imports of certain aluminum... by Aluminum Extrusions Fair Trade Committee and the United Steel, Paper and Forestry, Rubber...

Alcoa North American Extrusions Implements Energy Use Assessments at Multiple Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2001-08-01

This case study is the latest in a series on industrial firms who are implementing energy efficient technologies and system improvements into their manufacturing processes. The case studies document the activities, savings, and lessons learned on these projects.

In-line NIR spectroscopy for the understanding of polymer-drug interaction during pharmaceutical hot-melt extrusion.

PubMed

Saerens, Lien; Dierickx, Lien; Quinten, Thomas; Adriaensens, Peter; Carleer, Robert; Vervaet, Chris; Remon, Jean Paul; De Beer, Thomas

2012-05-01

The aim was to evaluate near-infrared spectroscopy for the in-line determination of the drug concentration, the polymer-drug solid-state behaviour and molecular interactions during hot-melt extrusion. Kollidon® SR was extruded with varying metoprolol tartrate (MPT) concentrations (20%, 30% and 40%) and monitored using NIR spectroscopy. A PLS model allowed drug concentration determination. The correlation between predicted and real MPT concentrations was good (R(2)=0.97). The predictive performance of the model was evaluated by the root mean square error of prediction, which was 1.54%. Kollidon® SR with 40% MPT was extruded at 105°C and 135°C to evaluate NIR spectroscopy for in-line polymer-drug solid-state characterisation. NIR spectra indicated the presence of amorphous MPT and hydrogen bonds between drug and polymer in the extrudates. More amorphous MPT and interactions could be found in the extrudates produced at 135°C than at 105°C. Raman spectroscopy, DSC and ATR FT-IR were used to confirm the NIR observations. Due to the instability of the formulation, only in-line Raman spectroscopy was an adequate confirmation tool. NIR spectroscopy is a potential PAT-tool for the in-line determination of API concentration and for the polymer-drug solid-state behaviour monitoring during pharmaceutical hot-melt extrusion. Copyright © 2012 Elsevier B.V. All rights reserved.

Quantitative assessment of apical debris extrusion and intracanal debris in the apical third, using hand instrumentation and three rotary instrumentation systems.

PubMed

H K, Sowmya; T S, Subhash; Goel, Beena Rani; T N, Nandini; Bhandi, Shilpa H

2014-02-01

Decreased apical extrusion of debris and apical one third debris have strong implications for decreased incidence of postoperative inflammation and pain. Thus, the aim of this study was to assess quantitatively the apical extrusion of debris and intracanal debris in the apical third during root canal instrumentation using hand and three different types of rotary instruments. Sixty freshly extracted single rooted human teeth were randomly divided into four groups. Canal preparation was done using step-back with hand instrumentation, crown-down technique with respect to ProTaper and K3, and hybrid technique with LightSpeed LSX. Irrigation was done with NaOCl, EDTA, and normal saline and for final irrigation, EndoVac system was used. The apically extruded debris was collected on the pre-weighed Millipore plastic filter disk and weighed using microbalance. The teeth were submitted to the histological processing. Sections from the apical third were analyzed by a trinocular research microscope that was coupled to a computer where the images were captured and analyzed using image proplus V4.1.0.0 software. The mean weight of extruded debris for each group and intracanal debris in the root canal was statistically analyzed by a Kruskal-Wallis one-way analysis of variance and Mann-Whitney U test. The result showed that, hand instrumentation using K files showed the highest amount of debris extrusion apically when compared to ProTaper, K3 and LightSpeed LSX. The result also showed that there was no statistically significant difference between the groups in relation to presence of intracanal debris in the apical one third. Based on the results, all instrumentation techniques produced debris extrusion. The engine driven Ni-Ti systems extruded significantly less apical debris than hand instrumentation. There was no statistically significant difference between the groups in relation to presence of intracanal debris in the apical one third.

Quantitative Assessment of Apical Debris Extrusion and Intracanal Debris in the Apical Third, Using Hand Instrumentation and Three Rotary Instrumentation Systems

PubMed Central

H.K., Sowmya; T.S., Subhash; Goel, Beena Rani; T.N., Nandini; Bhandi, Shilpa H.

2014-01-01

Introduction: Decreased apical extrusion of debris and apical one third debris have strong implications for decreased incidence of postoperative inflammation and pain. Thus, the aim of this study was to assess quantitatively the apical extrusion of debris and intracanal debris in the apical third during root canal instrumentation using hand and three different types of rotary instruments. Methodology: Sixty freshly extracted single rooted human teeth were randomly divided into four groups. Canal preparation was done using step-back with hand instrumentation, crown-down technique with respect to ProTaper and K3, and hybrid technique with LightSpeed LSX. Irrigation was done with NaOCl, EDTA, and normal saline and for final irrigation, EndoVac system was used. The apically extruded debris was collected on the pre-weighed Millipore plastic filter disk and weighed using microbalance. The teeth were submitted to the histological processing. Sections from the apical third were analyzed by a trinocular research microscope that was coupled to a computer where the images were captured and analyzed using image proplus V4.1.0.0 software. The mean weight of extruded debris for each group and intracanal debris in the root canal was statistically analyzed by a Kruskal-Wallis one-way analysis of variance and Mann-Whitney U test. Results: The result showed that, hand instrumentation using K files showed the highest amount of debris extrusion apically when compared to ProTaper, K3 and LightSpeed LSX. The result also showed that there was no statistically significant difference between the groups in relation to presence of intracanal debris in the apical one third. Conclusion: Based on the results, all instrumentation techniques produced debris extrusion. The engine driven Ni-Ti systems extruded significantly less apical debris than hand instrumentation. There was no statistically significant difference between the groups in relation to presence of intracanal debris in the apical one third. PMID:24701536

Enabling thermal processing of ritonavir-polyvinyl alcohol amorphous solid dispersions by KinetiSol® Dispersing.

PubMed

LaFountaine, Justin S; Jermain, Scott V; Prasad, Leena Kumari; Brough, Chris; Miller, Dave A; Lubda, Dieter; McGinity, James W; Williams, Robert O

2016-04-01

Polyvinyl alcohol has received little attention as a matrix polymer in amorphous solid dispersions (ASDs) due to its thermal and rheological limitations in extrusion processing and limited organic solubility in spray drying applications. Additionally, in extrusion processing, the high temperatures required to process often exclude thermally labile APIs. The purpose of this study was to evaluate the feasibility of processing polyvinyl alcohol amorphous solid dispersions utilizing the model compound ritonavir with KinetiSol® Dispersing (KSD) technology. The effects of KSD rotor speed and ejection temperature on the physicochemical properties of the processed material were evaluated. Powder X-ray diffraction and modulated differential scanning calorimetry were used to confirm amorphous conversion. Liquid chromatography-mass spectroscopy was used to characterize and identify degradation pathways of ritonavir during KSD processing and (13)C nuclear magnetic resonance spectroscopy was used to investigate polymer stability. An optimal range of processing conditions was found that resulted in amorphous product and minimal to no drug and polymer degradation. Drug release of the ASD produced from the optimal processing conditions was evaluated using a non-sink, pH-shift dissolution test. The ability to process amorphous solid dispersions with polyvinyl alcohol as a matrix polymer will enable further investigations of the polymer's performance in amorphous systems for poorly water-soluble compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

Fusion production of solid dispersions containing a heat-sensitive active ingredient by hot melt extrusion and Kinetisol dispersing.

PubMed

Dinunzio, James C; Brough, Chris; Hughey, Justin R; Miller, Dave A; Williams, Robert O; McGinity, James W

2010-02-01

Many techniques for the production of solid dispersions rely on elevated temperatures and prolonged material residence times, which can result in decomposition of temperature-sensitive components. In this study, hydrocortisone was used as a model temperature-sensitive active ingredient to study the effect of formulation and processing techniques as well as to characterize the benefits of KinetiSol Dispersing for the production of solid dispersions. Preformulation studies were conducted using differential scanning calorimetry and hot stage microscopy to identify optimum carriers for the production of amorphous solid dispersions. After identification, solid dispersions were prepared by hot melt extrusion and KinetiSol Dispersing, with material characterized by X-ray diffraction, dissolution and potency testing to evaluate physicochemical properties. Results from the preformulation studies showed that vinylacetate:vinylpyrrolidone (PVPVA) copolymer allowed for hydrocortisone dissolution within the carrier at temperatures as low as 160 degrees C, while hydroxypropyl methylcellulose required temperatures upward of 180 degrees C to facilitate solubilization. Low substituted hydroxypropyl cellulose, a high glass transition temperature control, showed that the material was unable to solubilize hydrocortisone. Manufacturing process control studies using hot melt extruded compositions of hydrocortisone and PVPVA showed that increased temperatures and residence times negatively impacted product potency due to decomposition. Using KinetiSol Dispersing to reduce residence time and to facilitate lower temperature processing, it was possible to produce solid dispersions with improved product potency. This study clearly demonstrated the importance of carrier selection to facilitate lower temperature processing, as well as the effect of residence time on product potency. Furthermore, KinetiSol Dispersing provided significant advantages over hot melt extrusion due to the reduced residence times and lower required processing temperatures. This allowed for the production of solid dispersions with enhanced product potency. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Extrusion of small-diameter, thin-wall tungsten tubing

NASA Technical Reports Server (NTRS)

Blankenship, C. P.; Gyorgak, C. A.

1967-01-01

Small-diameter, thin-wall seamless tubing of tungsten has been fabricated in lengths of up to 10 feet by hot extrusion over a floating mandrel. Extrusion of 0.50-inch-diameter tubing over 0.4-inch-diameter mandrels was accomplished at temperatures ranging from 3000 degrees to 4000 degrees F.

Spontaneous extrusion of a stainless steel glaucoma drainage implant (Ex-PRESS).

PubMed

Tavolato, M; Babighian, S; Galan, A

2006-01-01

To report a case of spontaneous extrusion of a stainless steel glaucoma drainage implant (Ex-PRESS). An Ex-PRESS was implanted under the conjunctiva in a 76-year-old man with primary open-angle glaucoma. Two years after implantation, the Ex-Press extruded spontaneously. Despite this adverse event, there was no increase in intraocular pressure. This is the first report of spontaneous extrusion of an Ex-PRESS device. Implanting the device under a scleral flap should be considered to avoid adverse events such as extrusion or conjunctival erosion.

Method for producing through extrusion an anisotropic magnet with high energy product

DOEpatents

Chandhok, Vijay K.

2004-09-07

A method for producing an anisotropic magnet with high energy product through extrusion and, more specifically, by placing a particle charge of a composition from the which magnet is to be produced in a noncircular container, heating the container and particle charge and extruding the container and particle charge through a noncircular extrusion die in such a manner that one of the cross-sectional axes or dimension of the container and particle charge is held substantially constant during the extrusion to compact the particle charge to substantially full density by mechanical deformation produced during the extrusion to achieve a magnet with anisotropic magnetic properties along the axes or dimension thereof and, more specifically, a high energy product along the transverse of the smallest cross-sectional dimension of the extruded magnet.

Extrusion without a motor: a new take on the loop extrusion model of genome organization

PubMed Central

Johnson, J.; Michieletto, D.; Morozov, A. N.; Nicodemi, M.; Cook, P. R.; Marenduzzo, D.

2018-01-01

ABSTRACT Chromatin loop extrusion is a popular model for the formation of CTCF loops and topological domains. Recent HiC data have revealed a strong bias in favour of a particular arrangement of the CTCF binding motifs that stabilize loops, and extrusion is the only model to date which can explain this. However, the model requires a motor to generate the loops, and although cohesin is a strong candidate for the extruding factor, a suitable motor protein (or a motor activity in cohesin itself) has yet to be found. Here we explore a new hypothesis: that there is no motor, and thermal motion within the nucleus drives extrusion. Using theoretical modelling and computer simulations we ask whether such diffusive extrusion could feasibly generate loops. Our simulations uncover an interesting ratchet effect (where an osmotic pressure promotes loop growth), and suggest, by comparison to recent in vitro and in vivo measurements, that diffusive extrusion can in principle generate loops of the size observed in the data. Extra View on : C. A. Brackley, J. Johnson, D. Michieletto, A. N. Morozov, M. Nicodemi, P. R. Cook, and D. Marenduzzo “Non-equilibrium chromosome looping via molecular slip-links”, Physical Review Letters 119 138101 (2017) PMID:29300120

Characterization of Al-Cu-Li Alloy 2090 Near Net Shape Extrusion

NASA Technical Reports Server (NTRS)

Birt, M. J.; Domack, M. S.; Hafley, R. A.; Pollock, W. D.

1998-01-01

Aluminum-lithium (Al-Li) alloys near net shape extrusions are being evaluated for potential application in launch vehicle structures. The objective of this study was to determine tensile and fracture properties, corrosion resistance, and weldability of integrally stiffened panels of Al-Cu-Li alloy 2090 in the T8 temper. The microstructure was pre-dominantly unrecrystallized. Texture analyses revealed the presence of fiber components in the stiffeners and a combination of fiber and rolling components in the skin. Variations in grain morphology and texture through the extruded cross section were correlated with the tensile, fracture, and corrosion behavior. Tensile strengths at room and cryogenic temperatures of the 2090 extrusions were similar to other 2090 product forms and were higher than 2219-T87, the primary structural material in the Space Shuttle external tank; however, ductilities were lower. The fracture resistance of the 2090 extrusion was lower than 2219-T87 plate at room temperature. At cryogenic temperatures, tensile ductility and fracture behavior of the 2090 extrusion were similar to other 2090 product forms but were lower than 2219-T87 plate. The exfoliation and stress corrosion resistance of the 2090 extrusion compared favorably with the characteristics of other 2090 product forms. The weldability and weldment properties of the extrusions were similar to 2090 and 2219 plates.

The effect of processing parameters during heat treatment of bulk high-T(sub c) superconductors

NASA Astrophysics Data System (ADS)

Cha, Y. S.; Dorris, S. E.; Hull, J. R.; Poeppel, R. B.

1991-04-01

Plastic extrusion is a promising method for producing the long lengths of high-Tc superconductor that will be necessary to meet many potential applications. A crucial phase of the extrusion method is removal of organic constituents. Incomplete removal can leave residual carbon at grain boundaries, which can adversely affect the superconducting properties, whereas excessively rapid removal of the organics can cause the extruded superconductor to disintegrate completely. In this paper, we analyze the effects of the following aspects of organics removal, as they apply to the firing of extruded YBa2Cu3O(x) coils: (1) total pressure in the furnace, (2) oxygen flow, (3) heat conduction, and (4) diffusion of volatile components during removal of organics.

Rheological Characterization of Molten Polymer-Drug Dispersions as a Predictive Tool for Pharmaceutical Hot-Melt Extrusion Processability.

PubMed

Van Renterghem, Jeroen; Vervaet, Chris; De Beer, Thomas

2017-11-01

The aim of this study was to investigate (i) the influence of drug solid-state (crystalline or dissolved in the polymer matrix) on the melt viscosity and (ii) the influence of the drug concentration, temperature and shear rate on polymer crystallization using rheological tests. Poly (ethylene oxide) (PEO) (100.000 g/mol) and physical mixtures (PM) containing 10-20-30-40% (w/w) ketoprofen or 10% (w/w) theophylline in PEO were rheologically characterized. Rheological tests were performed (frequency and temperature sweeps in oscillatory shear as well as shear-induced crystallization experiments) to obtain a thorough understanding of the flow behaviour and crystallization of PEO-drug dispersions. Theophylline did not dissolve in PEO as the complex viscosity (η*) of the drug-polymer mixture increased as compared to that of neat PEO. In contrast, ketoprofen dissolved in PEO and acted as a plasticizer, decreasing η*. Acting as a nucleating agent, theophylline induced the crystallization of PEO upon cooling from the melt. On the other hand, ketoprofen inhibited crystallization upon cooling. Moreover, higher concentrations of ketoprofen in the drug-polymer mixture increasingly inhibited polymer crystallization. However, shear-induced crystallization was observed for all tested mixtures containing ketoprofen. The obtained rheological results are relevant for understanding and predicting HME processability (e.g., barrel temperature selection) and downstream processing such as injection moulding (e.g., mold temperature selection).

Understanding the Thermal Properties of Precursor-Ionomers to Optimize Fabrication Processes for Ionic Polymer-Metal Composites (IPMCs)

PubMed Central

Choi, Kisuk; Olsen, Zakai; Hwang, Taeseon; Nam, Jae-Do

2018-01-01

Ionic polymer-metal composites (IPMCs) are one of many smart materials and have ionomer bases with a noble metal plated on the surface. The ionomer is usually Nafion, but recently Aquivion has been shown to be a promising alternative. Ionomers are available in the form of precursor pellets. This is an un-activated form that is able to melt, unlike the activated form. However, there is little study on the thermal characteristics of these precursor ionomers. This lack of knowledge causes issues when trying to fabricate ionomer shapes using methods such as extrusion, hot-pressing, and more recently, injection molding and 3D printing. To understand the two precursor-ionomers, a set of tests were conducted to measure the thermal degradation temperature, viscosity, melting temperature, and glass transition. The results have shown that the precursor Aquivion has a higher melting temperature (240 °C) than precursor Nafion (200 °C) and a larger glass transition range (32–65 °C compared with 21–45 °C). The two have the same thermal degradation temperature (~400 °C). Precursor Aquivion is more viscous than precursor Nafion as temperature increases. Based on the results gathered, it seems that the precursor Aquivion is more stable as temperature increases, facilitating the manufacturing processes. This paper presents the data collected to assist researchers in thermal-based fabrication processes. PMID:29693584

Pullout Fixation of Posterior Medial Meniscus Root Tears: Correlation Between Meniscus Extrusion and Midterm Clinical Results

PubMed

Chung, Kyu Sung; Ha, Jeong Ku; Ra, Ho Jong; Nam, Gun Woo; Kim, Jin Goo

2017-01-01

Medial meniscus posterior root tears (MMPRTs) lead to extrusion of the meniscus during weightbearing as well as loss of the ability of the meniscus to generate hoop stress. This loss of load-sharing ability leads to progressive arthritic changes. However, there have been no studies that correlate the correction of meniscus extrusion with clinical outcomes. Decreased meniscus extrusion is associated with better clinical and radiographic outcomes compared with increased meniscus extrusion after MMPRT pullout fixation. Case-control study; Level of evidence, 3. A total of 39 patients who underwent MMPRT pullout fixation and had been observed for more than 5 years were recruited for this study. The mean follow-up period was 69.8 months. Participants were categorized into 2 groups according to the direction of meniscus extrusion: group A (increased extrusion; 23 patients) and group B (decreased extrusion; 16 patients). Meniscus extrusion was assessed in the coronal plane on magnetic resonance imaging preoperatively and at 1 year postoperatively. The postoperative clinical outcomes (Lysholm and International Knee Documentation Committee [IKDC] scores) and radiographic results (Kellgren-Lawrence [K-L] grade and medial joint space) were compared between groups. Meniscus extrusion in group A increased significantly from a mean (±SD) of 3.5 ± 0.9 mm preoperatively to 5.1 ± 1.4 mm at 1 year postoperatively ( P < .001), whereas in group B, it decreased significantly from 4.1 ± 1.3 mm preoperatively to 3.5 ± 1.4 mm at 1 year postoperatively ( P < .001). The K-L arthritis grade (0/1/2/3/4) significantly progressed in group A (from 2/12/9/0/0 preoperatively to 0/1/14/8/0 postoperatively, respectively; P = .009) but not in group B (from 1/11/4/0/0 preoperatively to 0/6/8/2/0 postoperatively, respectively; P = .274). The mean final Lysholm and IKDC scores in group B (88.1 ± 12.1 and 79.0 ± 11.4, respectively) were significantly better than those in group A (81.0 ± 9.0 and 71.1 ± 7.8, respectively) ( P < .05). There was less medial joint space narrowing at final follow-up in group B (0.6 ± 0.8 mm) than in group A (1.1 ± 0.6 mm) ( P = .015). Progression of the K-L arthritis grade was seen in 50% (8/16) of the patients in group B compared with 87% (20/23) of the patients in group A ( P = .027). The current study demonstrates that in patients with MMPRTs, pullout fixation leads to favorable midterm outcomes, regardless of meniscus extrusion at 1-year follow-up. However, patients with decreased meniscus extrusion at postoperative 1 year have more favorable clinical scores and radiographic findings at midterm follow-up than those with increased extrusion at 1 year. This study indicates that one of the main goals of the repair of MMPRTs is to reduce meniscus extrusion as much as possible.

Predictive Modeling of Fast-Curing Thermosets in Nozzle-Based Extrusion

NASA Technical Reports Server (NTRS)

Xie, Jingjin; Randolph, Robert; Simmons, Gary; Hull, Patrick V.; Mazzeo, Aaron D.

2017-01-01

This work presents an approach to modeling the dynamic spreading and curing behavior of thermosets in nozzle-based extrusions. Thermosets cover a wide range of materials, some of which permit low-temperature processing with subsequent high-temperature and high-strength working properties. Extruding thermosets may overcome the limited working temperatures and strengths of conventional thermoplastic materials used in additive manufacturing. This project aims to produce technology for the fabrication of thermoset-based structures leveraging advances made in nozzle-based extrusion, such as fused deposition modeling (FDM), material jetting, and direct writing. Understanding the synergistic interactions between spreading and fast curing of extruded thermosetting materials will provide essential insights for applications that require accurate dimensional controls, such as additive manufacturing [1], [2] and centrifugal coating/forming [3]. Two types of thermally curing thermosets -- one being a soft silicone (Ecoflex 0050) and the other being a toughened epoxy (G/Flex) -- served as the test materials in this work to obtain models for cure kinetics and viscosity. The developed models align with extensive measurements made with differential scanning calorimetry (DSC) and rheology. DSC monitors the change in the heat of reaction, which reflects the rate and degree of cure at different crosslinking stages. Rheology measures the change in complex viscosity, shear moduli, yield stress, and other properties dictated by chemical composition. By combining DSC and rheological measurements, it is possible to establish a set of models profiling the cure kinetics and chemorheology without prior knowledge of chemical composition, which is usually necessary for sophisticated mechanistic modeling. In this work, we conducted both isothermal and dynamic measurements with both DSC and rheology. With the developed models, numerical simulations yielded predictions of diameter and height of droplets, along with width and height of extruded lines cured at varied temperatures. Experimental results carried out on a goniometric platform and a nozzle-based 3D printer showed agreement with the numerical simulations. Finally, this presentation will show how the models are adaptable to the planning of tool paths and designs in additive manufacturing.

Silane cross-linkable ethylene-propylene elastomer compositions prepared by reactive processing

NASA Astrophysics Data System (ADS)

Kozawa, Eiji; Nakajima, Yasuo; Kim, Jae Kyung

2015-05-01

Thermoplastic Elastomers (TPEs) have received attention as the alternative materials of EPDM due to an advantage for mass production. In recent years, by the progress of polymerization technology, Ethylene-propylene Elastomer (EP), one of the TPEs, is beginning to be applied to many products because of its good properties as rubber. However, as much as a complete replacement for EPDM, it is not provided with sufficient properties. In such circumstance, we found that EP's performance properties can be further enhanced via chemical modification such as cross-linking. The advent of a newer technique, involving the grafting of organo-functional silane onto the polymer chain in the reaction extrusion process is more attractive due to various industrial advantages. Although the functionalization of the EP by silane grafting through reactive processing is very useful, the silane grafting process of EP has a difficulty. It is most likely a consequence of the nature of the PP chain scission (β-scission), which is the dominant reaction in PP when subjected to free radicals at elevated temperature during processing. Therefore, the objective of our current work is to investigate a reactive extrusion process for the silane cross-linkable EP while minimizing the degradation, as well as evaluate the properties of the modified polymer.

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

PubMed

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. Copyright © 2013 Wiley Periodicals, Inc.

Microstructure evolution and tensile properties of Zr-2.5wt%Nb pressure tubes processed from billets with different microstructures

NASA Astrophysics Data System (ADS)

Kapoor, K.; Saratchandran, N.; Muralidharan, K.

1999-02-01

Starting with identical ingots, billets having different microstructures were obtained by three different processing methods for fabrication of Zr-2.5wt%Nb pressure tubes. The billets were further processed by hot extrusion and cold Pilger tube reducing to the finished product. Microstructural characterization was done at each stage of processing. The effects of the initial billet microstructure on the intermediate and final microstructure and mechanical property results were determined. It was found that the structure at each stage and the final mechanical properties depend strongly on the initial billet microstructure. The structure at the final stage consists of elongated alpha zirconium grains with a network of metastable beta zirconium phase. Some of this metastable phase transforms into stable beta niobium during thermomechanical processing. Billets with quenched structure resulted in less beta niobium at the final stage. The air cooled billets resulted in a large amount of beta niobium. The tensile properties, especially the percentage elongation, were found to vary for the different methods. Higher percentage elongation was observed for billets having quenched structure. Extrusion and forging did not produce any characteristic differences in the properties. The results were used to select a process flow sheet which yields the desired mechanical properties with suitable microstructure in the final product.

Fabrication of fine-grain tantalum diffusion barrier tube for Nb3Sn conductors

NASA Astrophysics Data System (ADS)

Hartwig, K. T.; Balachandran, S.; Mezyenski, R.; Seymour, N.; Robinson, J.; Barber, R. E.

2014-01-01

Diffusion barriers used in Nb3Sn wire are often fabricated by wrapping Ta sheet into a tube with an overlap seam. A common result of such practice is non-uniform deformation in the Ta sheet as it thins by wire drawing because of non-uniform grain size and texture in the original Ta sheet. Seamless Ta tube with a fine-grain and uniform microstructure would be much better for the diffusion barrier application, but such material is expensive and difficult to manufacture. This report presents results on a new fabrication strategy for Ta tube that shows promise for manufacture of less costly tube with an improved microstructure. The fabrication method begins with seam-welded tube but gives a fine-grain uniform microstructure with little difference between the longitudinal seam weld region and the parent metal after post-weld processing. Severe plastic deformation processing (SPD) applied by area reduction extrusion and tube equal channel angular extrusion (tECAE) are used to refine and homogenize the microstructure. Microstructure and mechanical property results are presented for Ta tubes fabricated by this new processing strategy.

Studies on the effect of storage time and plasticizers on the structural variations in thermoplastic starch.

PubMed

Schmitt, H; Guidez, A; Prashantha, K; Soulestin, J; Lacrampe, M F; Krawczak, P

2015-01-22

Starch was combined with plasticizers such as glycerol, sorbitol, glycerol/sorbitol and urea/ethanolamine blends by means of high shear extrusion process to prepare thermoplastic starch (TPS). Effect of storage time and plasticizers on the structural stability of melt processed TPS was investigated. Morphological observation, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy reveal that melt extrusion process is efficient in transforming granular starch into a plasticized starch for all plasticizer compositions. XRD analysis highlights major changes in the microstructure of plasticized starch, and dependence of crystalline type and degree of crystallinity mainly on the plasticizer composition and storage time. Dynamical mechanical analysis (DMA) yields a decrease of the peak intensity of loss factor with aging time. The effect of ageing on tensile strength also appears to be highly dependent on the plasticizer composition. Thus, through different plasticizer combinations and ageing, starch-based materials with significant differences in tensile properties can be obtained, which may be tuned to meet the requirements of a wide range of applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

Influence of extrusion-cooking parameters on some quality aspects of precooked pasta-like products.

PubMed

Wójtowicz, A; Mościcki, L

2009-06-01

The present article aims to evaluate some quality parameters and texture characteristics of precooked wheat pasta-like products. Using the methods for pasta and instant noodles the tested parameters were water absorption, starch gelatinization degree, cooking losses, and hardness. The texture profile was characterized using Zwick apparatus by cutting test with the head speed of 10 mm/min and expressed as hardness and firmness of hydrated products. SEM pictures were used to illustrate the internal structure of dry and cooked pasta-like products. Dough moisture content and process conditions influenced all tested quality parameters of the pasta-like products processed on a modified single screw extrusion-cooker TS-45 with L: D = 16: 1. Good organoleptical quality (notes higher than 4 in a 5-point scale) and firm texture were observed for common wheat flour pasta processed at 30% m.c. Hardness and firmness of hydrated products lowered with a longer hydration time in hot water. The firmest texture and low stickiness was observed for products with a highest starch gelatinization degree.

Biopolymer foams - Relationship between material characteristics and foaming behavior of cellulose based foams

NASA Astrophysics Data System (ADS)

Rapp, F.; Schneider, A.; Elsner, P.

2014-05-01

Biopolymers are becoming increasingly important to both industry and consumers. With regard to waste management, CO2 balance and the conservation of petrochemical resources, increasing efforts are being made to replace standard plastics with bio-based polymers. Nowadays biopolymers can be built for example of cellulose, lactic acid, starch, lignin or bio mass. The paper will present material properties of selected cellulose based polymers (cellulose propionate [CP], cellulose acetate butyrate [CAB]) and corresponding processing conditions for particle foams as well as characterization of produced parts. Special focus is given to the raw material properties by analyzing thermal behavior (differential scanning calorimetry), melt strength (Rheotens test) and molecular weight distribution (gel-permeation chromatography). These results will be correlated with the foaming behavior in a continuous extrusion process with physical blowing agents and underwater pelletizer. Process set-up regarding particle foam technology, including extrusion foaming and pre-foaming, will be shown. The characteristics of the resulting foam beads will be analyzed regarding part density, cell morphology and geometry. The molded parts will be tested on thermal conductivity as well as compression behavior (E-modulus, compression strength).

Identification of Heterotrophic Zinc Mobilization Processes among Bacterial Strains Isolated from Wheat Rhizosphere (Triticum aestivum L.).

PubMed

Costerousse, Benjamin; Schönholzer-Mauclaire, Laurie; Frossard, Emmanuel; Thonar, Cécile

2018-01-01

Soil and plant inoculation with heterotrophic zinc-solubilizing bacteria (ZSB) is considered a promising approach for increasing zinc (Zn) phytoavailability and enhancing crop growth and nutritional quality. Nevertheless, it is necessary to understand the underlying bacterial solubilization processes to predict their repeatability in inoculation strategies. Acidification via gluconic acid production remains the most reported process. In this study, wheat rhizosphere soil serial dilutions were plated on several solid microbiological media supplemented with scarcely soluble Zn oxide (ZnO), and 115 putative Zn-solubilizing isolates were directly detected based on the formation of solubilization halos around the colonies. Eight strains were selected based on their Zn solubilization efficiency and siderophore production capacity. These included one strain of Curtobacterium , two of Plantibacter , three strains of Pseudomonas , one of Stenotrophomonas , and one strain of Streptomyces In ZnO liquid solubilization assays, the presence of glucose clearly stimulated organic acid production, leading to medium acidification and ZnO solubilization. While solubilization by Streptomyces and Curtobacterium was attributed to the accumulated production of six and seven different organic acids, respectively, the other strains solubilized Zn via gluconic, malonic, and oxalic acids exclusively. In contrast, in the absence of glucose, ZnO dissolution resulted from proton extrusion (e.g., via ammonia consumption by Plantibacter strains) and complexation processes (i.e., complexation with glutamic acid in cultures of Curtobacterium ). Therefore, while gluconic acid production was described as a major Zn solubilization mechanism in the literature, this study goes beyond and shows that solubilization mechanisms vary among ZSB and are strongly affected by growth conditions. IMPORTANCE Barriers toward a better understanding of the mechanisms underlying zinc (Zn) solubilization by bacteria include the lack of methodological tools for isolation, discrimination, and identification of such organisms. Our study proposes a direct bacterial isolation procedure, which prevents the need to screen numerous bacterial candidates (for which the ability to solubilize Zn is unknown) for recovering Zn-solubilizing bacteria (ZSB). Moreover, we confirm the potential of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) as a quick and accurate tool for the identification and discrimination of environmental bacterial isolates. This work also describes various Zn solubilization processes used by wheat rhizosphere bacteria, including proton extrusion and the production of different organic acids among bacterial strains. These processes were also clearly affected by growth conditions (i.e., solid versus liquid cultures and the presence and absence of glucose). Although highlighted mechanisms may have significant effects at the soil-plant interface, these should only be transposed cautiously to real ecological situations. Copyright © 2017 American Society for Microbiology.

Autoclave heat treatment for prealloyed powder products

NASA Technical Reports Server (NTRS)

Freche, J. C.; Ashbrook, R. L.

1973-01-01

Technique could be applied directly to loose powders as part of hot pressing process of forming them to any required shapes. This would eliminate initial extrusion step commonly applied to prealloyed powders, substantially reduce cost of forming operation, and result in optimum properties.

Effects of Plastizers on the Structure and Properties of Starch-Clay Nanocomposites

USDA-ARS?s Scientific Manuscript database

Biodegradable nanocomposites were successfully fabricated from corn starch and montmorillonite (MMT) nanoclays by melt extrusion processing. The structure and morphology of the nanocomposites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and film propertie...

TPS/PCL composite reinforced with treated sisal fibers: property, biodegradation and water-absorption

USDA-ARS?s Scientific Manuscript database

Sisal fibers bleached with sodium-hydroxide followed by hydrogen peroxide treatment were incorporated in a thermoplastic starch;-polycaprolactone (TPS/PCL) blend via extrusion processing and examined for their property, biodegradability and water-absorption. Scanning electron microscopy revealed wel...

Causes and Mitigation of Fuel Pilot Operated Valve Pilot Seal Extrusion in Space Shuttle Orbiter Primary RCS Thrusters

NASA Technical Reports Server (NTRS)

Waller, Jess M.; Roth, Tim E.; Saulsberry, Regor L.; Haney, William A.; Kelly, Terence S; Forsyth, Bradley S.

2004-01-01

Extrusion of a polytetrafluoroethylene (PTFE) pilot seal located in the Space Shuttle Orbiter Primary Reaction Control Subsystem (PRCS) thruster fuel valve has been implicated in 68 ground and on-orbit fuel valve failures. A rash of six extrusion-related in-flight anomalies over a six-mission span from December 2001 to October 2002 led to heightened activity at various NASA centers, and the formation of a multidisciplinary team to solve the problem. Empirical and theoretical approaches were used. For example, thermomechanical analysis (TMA) and exposure tests showed that some extrusion is produced by thermal cycling; however, a review of thruster service histories did not reveal a strong link between thermal cycling and extrusion. Calculations showed that the amount of observed extrusion often exceeded the amount allowed by thermally-induced stress relief. Failure analysis of failed hardware also revealed the presence of fuel-oxidizer reaction product (FORP) inside the fuel valve pilot seal cavity, and differential scanning calorimetry (DSC) showed that the FORP was intimately associated with the pilot seal material. Component-level exposure tests showed that FORP of similar composition could be produced by adjacent oxidizer valve leakage in the absence of thruster firing. Specific gravity data showed that extruded fuel valve pilot seals were less dense than new pilot seals or oxidizer valve pilot seals, indicating permanent modification of the PTFE occurred during service. It is concluded that some thermally-induced extrusion is unavoidable; however, oxidizer leakage-induced extrusion is mostly avoidable and can be mitigated. Several engineering level mitigation strategies are discussed.

Hot Melt Extruded and Injection Moulded Dosage Forms: Recent Research and Patents.

PubMed

Major, Ian; McConville, Christopher

2015-01-01

Hot Melt Extrusion (HME) and Injection Moulding (IM) are becoming more prevalent in the drug delivery field due to their continuous nature and advantages over current pharmaceutical manufacturing techniques. Hot melt extrusion (HME) is a process that involves the use of at least one reciprocating screw to force a thermoplastic resin along a heated barrel and through a die, while injection moulding is a forming process were molten polymer is forced at high pressure to enter a mould. HME offers a number of advantages over conventional pharmaceutical manufacturing techniques such as increased solubility and bioavailability of poorly water soluble drugs, a solvent free and continuous process, improved content uniformity and flexibility in manufacture. Injection moulding (IM) has been recognised as a rapid and versatile manufacturing technique, which has the advantages of being a continuous process, which is easily scaled up by the use of larger equipment and moulds. However, despite their advantages and the significant number of publications and patents on HME and IM drug delivery devices there are very few marketed formulations. These marketed products range from oral dosage forms which improve bioavailability and reduce pill burden to vaginal rings which provide long-term controlled release thus improving patient compliance. The patenting strategy for IM and HME seems to be focused towards patenting the finished product, more so than patenting the manufacturing process. This is probably due to the fact that the IM and HME processes have already been patented. HME is a process where raw materials (i.e. polymer, plasticizer, drug etc.) are mixed and pumped along by a rotating screw(s) at elevated temperatures through a die to produce a product of uniform shape. IM is similar to HME except that the raw materials are pushed into a mould which is set at lower temperatures. Interest in the use of HME and IM within the pharmaceutical industry is growing with as steady increase in the number of HME patents being issued and with more than 10 products, ranging from oral dosage forms to implantable devices, currently on the market. Therefore, this review of HME and IM is important to the scientific community to further understand and advance these novel and exciting manufacturing techniques.

Characteristics of rapeseed oil cake using nitrogen adsorption

NASA Astrophysics Data System (ADS)

Sokołowska, Z.; Bowanko, G.; Boguta, P.; Tys, J.; Skiba, K.

2013-09-01

Adsorption of nitrogen on the rapeseed oil cake and rapeseed oil cake with wheat meal extrudates was investigated. The results are presented as adsorption-desorption isotherms. The Brunauer-Emmet and Teller equation was used to analyse the experimental sorption data. To obtain estimates of the surface area and surface fractal dimension, the sorption isotherms were analyzed using the Brunauer-Emmet and Teller and Frenkel-Halsey-Hill equations. Mesopore analysis was carried out using the Dollimore and Heal method. The properties and surface characteristic of rapeseed oil cake extrudates are related to different basic properties of particular samples and duration of the extrusion process. Extrusion conditions lead to essential differences in particular products. For all kinds of rapeseed oil cakes the amount of adsorbed nitrogen was different, but for the rapeseed oil cake extrudates a large amount of adsorbed nitrogenwas observed. The average surface area of the rapeseed oil cake extrudates was about 6.5-7.0 m2 g-1, whereas it was equal to about 4.0-6.0 m2 g-1 for rapeseed oil cake with the wheat meal extrudates. In the case of non-extruded rapeseed oil cake and wheat meal, the dominant group included ca. 2 and 5 nmpores. The values of surface fractal dimension suggested that the surface of the extrudates was more homogenous than that of the raw material. Duration of the extrusion process to 80 s resulted in a decrease in the specific surface area, surface fractal dimension, and porosity of the extrudates.

Hot-Melt Extrusion: from Theory to Application in Pharmaceutical Formulation.

PubMed

Patil, Hemlata; Tiwari, Roshan V; Repka, Michael A

2016-02-01

Hot-melt extrusion (HME) is a promising technology for the production of new chemical entities in the developmental pipeline and for improving products already on the market. In drug discovery and development, industry estimates that more than 50% of active pharmaceutical ingredients currently used belong to the biopharmaceutical classification system II (BCS class II), which are characterized as poorly water-soluble compounds and result in formulations with low bioavailability. Therefore, there is a critical need for the pharmaceutical industry to develop formulations that will enhance the solubility and ultimately the bioavailability of these compounds. HME technology also offers an opportunity to earn intellectual property, which is evident from an increasing number of patents and publications that have included it as a novel pharmaceutical formulation technology over the past decades. This review had a threefold objective. First, it sought to provide an overview of HME principles and present detailed engineered extrusion equipment designs. Second, it included a number of published reports on the application of HME techniques that covered the fields of solid dispersions, microencapsulation, taste masking, targeted drug delivery systems, sustained release, films, nanotechnology, floating drug delivery systems, implants, and continuous manufacturing using the wet granulation process. Lastly, this review discussed the importance of using the quality by design approach in drug development, evaluated the process analytical technology used in pharmaceutical HME monitoring and control, discussed techniques used in HME, and emphasized the potential for monitoring and controlling hot-melt technology.

78 FR 34984 - Aluminum Extrusions From the People's Republic of China: Notice of Court Decision Not in Harmony...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-11

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-967; C-570-968] Aluminum... (AD) and countervailing duty (CVD) orders on aluminum extrusions,\\1\\ pursuant to the CIT's remand... Rail Kits \\2\\ and is amending its final scope ruling. \\1\\ See Aluminum Extrusions from the People's...

75 FR 34482 - Certain Aluminum Extrusions From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-17

...)] Certain Aluminum Extrusions From China Determinations On the basis of the record \\1\\ developed in the... reason of imports from China of certain aluminum extrusions, provided for in subheadings 7604.21, 7604.29... United States at less than fair value (LTFV) and subsidized by the Government of China. \\1\\ The record is...

Influence of dried Hokkaido pumpkin and ascorbic acid addition on chemical properties and colour of corn extrudates.

PubMed

Obradović, Valentina; Babić, Jurislav; Šubarić, Drago; Jozinović, Antun; Ačkar, Đurđica; Klarić, Ilija

2015-09-15

The influence of Hokkaido pumpkin powder (PP) addition to corn grits at levels 4%, 6%, and 8% and ascorbic acid (AA) addition at levels 0.5% and 1% was evaluated. Extrusion was done using a single-screw extruder at two temperature regimes: 135/170/170°C (E1) and 100/150/150°C (E2). Mathematical models that describe the influence of additives on the colour of extrudates were determined. Raw extrusion mixtures as well as obtained extrudates were tested for ascorbic acid, polyphenol, proteins, fat, crude fibre, ash and carotenoids content, and antioxidant activity. E1 extrusion regime acted favourably on polyphenols, crude fibre content, and antioxidant activity. It also caused higher fat degradation than E2 extrusion. Xanthophylls (lutein and zeaxanthin) were less sensitive to extrusion than carotenes (α-carotene, 9-cis-β-carotene and 13-cis-β-carotene). Ascorbic acid was more sensitive to higher extrusion temperatures (49-76% degradation). It provided protection to carotenoids and consequently the colour of the extrudates. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of Humidity of Poly-Cereal Flour Mixture and Screw Rotation Rate on Efficiency of Extrusion Process

ERIC Educational Resources Information Center

Ospanov, ?bdymanap ?.; Muslimov, Nurzhan Zh.; Timurbekova, ?igul ?.; Jumabekova, Gulnar? B.

2016-01-01

The food industry is an important constituent of a country's economy, which provides the population with food. The development of the food industry and the supply of food products to the entire population requires improving food-manufacturing technologies, such as the process for production of extruded poly-cereal food products using…

Improvements to the single screw extruder

NASA Technical Reports Server (NTRS)

Hiemenz, C.; Ziegmann, G.; Franzkoch, B.; Hoffmanns, W.; Michaeli, W.

1977-01-01

The extrusion on a single screw extruder is examined. The process is divided into several steps: the dosage of the materials to be conveyed; the modification of the shape of the feeding opening which influences the feeding process and consequently the throughput of the extruder; optimizing the shape of the feeding zone to meet the specific material requirements; and plasticizing and homogenizing.

Effects of Deformation Texture Intensities and Precipitates on the Anisotropy of Mechanical Properties of Al-Li Alloy 2099 T83 Extrusions

NASA Astrophysics Data System (ADS)

Bois-Brochu, Alexandre; Blais, Carl; Goma, Franck Armel Tchitembo; Larouche, Daniel; Boselli, Julien; Brochu, Mathieu

The use of aluminum-lithium alloys in aerospace applications requires a thorough knowledge of how processing and product geometry impact their microstructure, texture and mechanical properties. As with other aluminum alloys, anisotropy of mechanical properties has been related to the formation of deformation textures during thermo-mechanical processes.

One-step internal-tin Nb/sub 3/Sn superconductor fabrication. Final report, June 1983-August 1984

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marancik, W.

1985-03-01

The object of this research is to demonstrate the feasibility of producing a Nb/sub 3/Sn superconductor in a single extrusion process with a large number of filaments with internal tin. The technique chosen uses .010'-diameter Nb and tin-plated Cu wires formed into a solenoid. The solenoid is covered with tin-plated copper foil and isostatically compacted to a pressure of 17,000 psi. The solenoid is slit along its length. This results in a ribbon about 40 inches long by about 5-inches wide, with the Nb wires running across the 5-inch-width. The ribbon is then rolled up (Jelly Roll) around a 0.5more » inch diameter Ta covered copper rod to produce a composite of about 1.5 inches in diameter by 5 inches long. The composite geometry is now a cylindrical bundle of 0.010-inch-diameter Nb wire separated from each other by tin-plated copper. Each Nb wire is aligned with the axis of cylinder. The cylinder is slid into a Ta-lined copper extrusion can which is evacuated and sealed. The can is extruded at a low temperature and drawn to final wire size without intermediate annealing. The advantage of the process is that it is an internal tin process with the tin uniformly distributed through the matrix. The Nb is in a relatively soft state having been fully annealed at 0.020-inch diameter. Only one extrusion is required since the bundling technique allows a large number of wires to be precisely aligned and spaced in the matrix.« less

Effect of Processing Route on Strain Controlled Low Cycle Fatigue Behavior of Polycrystalline NiAl

NASA Technical Reports Server (NTRS)

Rao, K. Bhanu Sankara; Lerch, B. A.; Noebe, R. D.

1995-01-01

The present investigation examines the effects of manufacturing process on the total axial strain controlled low cycle fatigue behavior of polycrystalline NiAl at 1000 K, a temperature above the monotonic Brittle-to-Ductile Transition Temperature (BDTT). The nickel aluminide samples were produced by three different processing routes: hot isostatic pressing of pre- alloyed powders, extrusion of prealloyed powders, and extrusion of vacuum induction melted ingots. The LCF behavior of the cast plus extruded material was also determined at room temperature (below the BD77) for comparison to the high temperature data. The cyclic stress response, cyclic stress-strain behavior, and strain-life relationships were influenced by the alloy preparation technique and the testing temperature. Detailed characterization of the LCF tested samples was conducted by optical and electron microscopy to determine the variations in fracture and deformation modes and to determine any microstructural changes that occurred during LCF testing. The dependence of LCF properties on processing route was rationalized on the basis of starting microstructure, brittle-to-ductile transition temperature, deformation induced changes in the basic microstructure, deformation substructure, and synergistic interaction between the damage modes.

Liner for extrusion billet containers. Interim Technical Documentary Progress Report, February 1--April 30, 1963

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spachner, S. A.

1963-05-01

A shrink-fit assembly device for buildup of ceramiccoated liner and sleeve assemblies was tested and modified to develop desired temperatures and suitable heat distribution in sleeves, which were heated. Nine different compositions of fiber metal reinforced ceramic compacts were produced for preliminary evaluation of suitability for extrusion liner use. Procedures were developed for welding short, hollow ceramic cylinders of high-strength metal carbides and borides to form a ceramic extrusion liner of suitable length. Dissassembly tooling for rapid separation of shrink-fitted sleeves from a worn liner was designed, fabricated, and tested. Preliminary extrusion testing of an alumina-coated liner was carried out,more » using SAE 4340 steel billets extruded to rod at 12 : 1 and 16 : 1 ratios. No coating wear was noted after extrusion of 3 billets. (auth)« less

FORMING TUBES AND RODS OF URANIUM METAL BY EXTRUSION

DOEpatents

Creutz, E.C.

1959-01-27

A method and apparatus are presented for the extrusion of uranium metal. Since uranium is very brittle if worked in the beta phase, it is desirable to extrude it in the gamma phase. However, in the gamma temperature range thc uranium will alloy with the metal of the extrusion dic, and is readily oxidized to a great degree. According to this patent, uranium extrusion in thc ganmma phase may be safely carried out by preheating a billet of uranium in an inert atmosphere to a trmperature between 780 C and 1100 C. The heated billet is then placed in an extrusion apparatus having dies which have been maintained at an elevated temperature for a sufficient length of time to produce an oxide film, and placing a copper disc between the uranium billet and the die.

Birth of an oceanic spreading center at a magma-poor rift system.

PubMed

Gillard, Morgane; Sauter, Daniel; Tugend, Julie; Tomasi, Simon; Epin, Marie-Eva; Manatschal, Gianreto

2017-11-08

Oceanic crust is continuously created at mid-oceanic ridges and seafloor spreading represents one of the main processes of plate tectonics. However, if oceanic crust architecture, composition and formation at present-day oceanic ridges are largely described, the processes governing the birth of a spreading center remain enigmatic. Understanding the transition between inherited continental and new oceanic domains is a prerequisite to constrain one of the last major unsolved problems of plate tectonics, namely the formation of a stable divergent plate boundary. In this paper, we present newly released high-resolution seismic reflection profiles that image the complete transition from unambiguous continental to oceanic crusts in the Gulf of Guinea. Based on these high-resolution seismic sections we show that onset of oceanic seafloor spreading is associated with the formation of a hybrid crust in which thinned continental crust and/or exhumed mantle is sandwiched between magmatic intrusive and extrusive bodies. This crust results from a polyphase evolution showing a gradual transition from tectonic-driven to magmatic-driven processes. The results presented in this paper provide a characterization of the domain in which lithospheric breakup occurs and enable to define the processes controlling formation of a new plate boundary.

Predicting melt rheology for hot-melt extrusion by means of a simple Tg-measurement.

PubMed

Bochmann, Esther S; Üstüner, Elgin E; Gryczke, Andreas; Wagner, Karl G

2017-10-01

The feasibility of predicting melt rheology by using the glass transition temperature (T g ) of a desired amorphous solid dispersion (ASD) for hot-melt extrusion (HME) and other melt based processes is presented. Three groups of three different active pharmaceutical ingredients (APIs) or plasticizer/copovidone mixtures, with identical glass transition in rheological testing, were used. Their rheological behavior as a function of temperature and frequency were analyzed by means of small amplitude oscillatory shear (SAOS) on an oscillatory rheometer. The zero-shear viscosity (η 0 ) identified at 150°C was compared to T g , measured by differential scanning calorimetry (DSC) and SAOS. A strong correlation between η 0 and T g was identified, independent of the API or plasticizer used to achieve T g of the mixture. To evaluate and rate the discrepancy in η 0 of the different mixtures at same T g , hot-melt extrusion trials were conducted to measure torque and mean residence time. In this paper, carbamazepine, dipyridamole, indomethacin, ibuprofen, polyethylene glycol (PEG 1500) in vinylpyrrolidone-vinyl acetate copolymer (copovidone) as matrix polymer were used. Copyright © 2017. Published by Elsevier B.V.

Microstructure and Mechanical Properties of Ultrafine-Grained Al-6061 Prepared Using Intermittent Ultrasonic-Assisted Equal-Channel Angular Pressing

NASA Astrophysics Data System (ADS)

Lu, Jianxun; Wu, Xiaoyu; Wu, Zhaozhi; Liu, Zhiyuan; Guo, Dengji; Lou, Yan; Ruan, Shuangchen

2017-10-01

Equal-channel angular pressing (ECAP) is an efficient technique to achieve grain refinement in a wide range of materials. However, the extrusion process requires an excessive extrusion force, the microstructure of ECAPed specimens scatters heterogeneously because of considerable fragmentation of the structure and strain heterogeneity, and the resultant ultrafine grains exhibit poor thermal stability. The intermittent ultrasonic-assisted ECAP (IU-ECAP) approach was proposed to address these issues. In this work, ECAP and IU-ECAP were applied to produce ultrafine-grained Al-6061 alloys, and the differences in their mechanical properties, microstructural characteristics, and thermal stability were investigated. Mechanical testing demonstrated that the necessary extrusion force for IU-ECAP was significantly reduced; even more, the microhardness and ultimate tensile strength were strengthened. In addition, the IU-ECAPed Al alloy exhibited a smaller grain size with a more homogeneous microstructure. X-ray diffraction analysis indicated that the intensities of the textures were weakened using IU-ECAP, and a more homogeneous microstructure and larger dislocation densities were obtained. Investigation of the thermal stability revealed that the ultrafine-grained materials produced using IU-ECAP recrystallized at higher temperature or after longer time; the materials thus exhibited improved thermal stability.

Worm melt fracture and fast die build-up at high shear rates in extrusion blow molding of large drums

NASA Astrophysics Data System (ADS)

Inn, Yong Woo; Sukhadia, Ashish M.

2017-05-01

In the extrusion blow molding process of high density polyethylene (HDPE) for making of large size drums, string-like defects, which are referred to as worm melt fracture in the industry, are often observed on the extrudate surface. Such string-like defects in various shapes and sizes are observed in capillary extrusion at very high shear rates after the slip-stick transition. The HDPE resin with broader molecular weight distribution (MWD) exhibits a greater degree of worm melt fracture while the narrow MWD PE resin, which has higher slip velocity and a uniform slip layer, shows a lesser degree of worm melt fracture. It is hypothesized that the worm melt fracture is related to fast die build-up and cohesive slip layer, a failure within the polymer melts at an internal surface. If the cohesive slip layer at an internal surface emerges out from the die, it can be attached on the surface of extrudate as string-like defects, the worm melt fracture. The resin having more small chains and lower plateau modulus can be easier to have such an internal failure and consequently exhibit more "worm" defects.

Application of quality by design (QbD) to formulation and processing of naproxen pellets by extrusion-spheronization.

PubMed

Wang, Junlin; Kan, Shuling; Chen, Tong; Liu, Jianping

2015-03-01

The aim of this research was to apply quality by design (QbD) to the development of naproxen loaded core pellets which can be used as the potential core for colon-specific pellets. In the early stages of this study, prior knowledge and preliminary studies were systematically incorporated into the risk assessment using failure mode and effect analysis (FMEA) and fishbone diagram. Then Plackett-Burman design was used to screen eight potential high risk factors (spheronization speed, spheronization time, extrusion speed, drying method, CCMC-Na concentration, lactose concentration, water concentration and Tween 80 concentration) obtained from the above risk assessment. It was discovered that out of the eight potential high risk factors only three factors (spheronization speed, extrusion speed and CCMC-Na concentration) had significant effects on the quality of the pellets. This allowed the use of Box-Behnken design (BBD) to fully elucidate the relationship between the variables and critical quality attribute (CQA). Finally, the final control space was established within which the quality of the pellets can meet the requirement of colon-specific drug delivery system. This study demonstrated that naproxen loaded core pellets were successfully designed using QbD principle.

Location of the tibial tunnel aperture affects extrusion of the lateral meniscus following reconstruction of the anterior cruciate ligament.

PubMed

Kodama, Yuya; Furumatsu, Takayuki; Miyazawa, Shinichi; Fujii, Masataka; Tanaka, Takaaki; Inoue, Hiroto; Ozaki, Toshifumi

2017-08-01

The anterior root of the lateral meniscus provides functional stability to the meniscus. In this study, we evaluated the relationship between the position of the tibial tunnel and extrusion of the lateral meniscus after anterior cruciate ligament reconstruction, where extrusion provides a proxy measure of injury to the anterior root. The relationship between extrusion and tibial tunnel location was retrospectively evaluated from computed tomography and magnetic resonance images of 26 reconstructed knees, contributed by 25 patients aged 17-31 years. A measurement grid was used to localize the position of the tibial tunnel based on anatomical landmarks identified from the three-dimensional reconstruction of axial computed tomography images of the tibial plateaus. The reference point-to-tibial tunnel distance (mm) was defined as the distance from the midpoint of the lateral edge of the grid to the posterolateral aspect of the tunnel aperture. The optimal cutoff of this distance to minimize post-operative extrusion was identified using receiver operating curve analysis. Extrusion of the lateral meniscus was positively correlated to the reference point-to-tibial tunnel distance (r 2  = 0.64; p < 0.001), with a cutoff distance of 5 mm having a sensitivity to extrusion of 83% and specificity of 93%. The mean extrusion for a distance >5 mm was 0.40 ± 0.43 mm, compared to 1.40 ± 0.51 mm for a distance ≤5 mm (p < 0.001). Therefore, a posterolateral location of the tibial tunnel aperture within the footprint of the anterior cruciate ligament decreases the reference point-to-tibial tunnel distance and increases extrusion of the lateral meniscus post-reconstruction. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1625-1633, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

The significance of late-stage processes in lava flow emplacement: squeeze-ups in the 2001 Etna flow field

NASA Astrophysics Data System (ADS)

Applegarth, L. J.; Pinkerton, H.; James, M. R.

2009-04-01

The general processes associated with the formation and activity of ephemeral boccas in lava flow fields are well documented (e.g. Pinkerton & Sparks 1976; Polacci & Papale 1997). The importance of studying such behaviour is illustrated by observations of the emplacement of a basaltic andesite flow at Parícutin during the 1940s. Following a pause in advance of one month, this 8 km long flow was reactivated by the resumption of supply from the vent, which forced the rapid drainage of stagnant material in the flow front region. The material extruded during drainage was in a highly plastic state (Krauskopf 1948), and its displacement allowed hot fluid lava from the vent to be transported in a tube to the original flow front, from where it covered an area of 350,000 m2 in one night (Luhr & Simkin 1993). Determining when a flow has stopped advancing, and cannot be drained in such a manner, is therefore highly important in hazard assessment and flow modelling, and our ability to do this may be improved through the examination of relatively small-scale secondary extrusions and boccas. The 2001 flank eruption of Mt. Etna, Sicily, resulted in the emplacement of a 7 km long compound `a`ā flow field over a period of 23 days. During emplacement, many ephemeral boccas were observed in the flow field, which were active for between two and at least nine days. The longer-lived examples initially fed well-established flows that channelled fresh material from the main vent. With time, as activity waned, the nature of the extruded material changed. The latest stages of development of all boccas involved the very slow extrusion of material that was either draining from higher parts of the flow or being forced out of the flow interior as changing local flow conditions pressurised parts of the flow that had been stagnant for some time. Here we describe this late-stage activity of the ephemeral boccas, which resulted in the formation of ‘squeeze-ups' of lava with a markedly different texture to that of the surrounding `a`ā flow surface. The appearance of the squeeze-up material in this flow is similar to that of the plastic lava forcibly drained from the front of the Parícutin flow. The squeeze-up features demonstrate marked morphological variation, which was found to reflect the rheology of the material being extruded, the volume of material being extruded, the extrusion rate and the geometry of the source bocca. We describe the final morphology of squeeze-ups from the 2001 flow field, which ranges from relatively fluid flows to extrusions of high-strength material that accumulated above the source bocca, forming features more akin to tumuli. Although tumulus-like in overall shape and dimensions, the morphology and inferred growth mechanisms for these structures leads to them being dubbed ‘exogenous tumuli', to distinguish them from the more familiar tumuli resulting from inflation processes, which are described elsewhere (e.g. Macdonald 1972; Walker 1991; Duncan et al. 2004). The morphological data are then used together with observations of lava surface textures and squeeze-up locations to build up a picture of flow structure and flow dynamics at the time of squeeze-up formation. The structure of the crust underlying the clinker cover can be elucidated by examining the locations in which squeeze-ups occur, as extrusions exploit zones of crustal weakness. It is found that the flow crust plays an increasingly important role in determining the locus of squeeze-ups as the flow evolves. Squeeze-ups that clearly had a high strength upon extrusion formed as a result of high overpressures in the flow interior. The extrusion of such material may represent the latter stages of activity of a long-lived bocca, or the new development of a bocca in a part of the flow that had been stagnant for some time. Examination of squeeze-up textures may help determine whether the material was transported to the extrusion site in an open or closed system, or if it was stored for a significant length of time before extrusion. Information may also be gleaned concerning the maximum crystallinity at which lava can flow, which is an important parameter in flow modelling. Evidence for a mechanism by which sufficient overpressure can be generated to extrude such material is presented.

GRAPHITE EXTRUSIONS

DOEpatents

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.

Reactive Melt Extrusion To Improve the Dissolution Performance and Physical Stability of Naproxen Amorphous Solid Dispersions.

PubMed

Liu, Xu; Zhou, Lin; Zhang, Feng

2017-03-06

The purpose of this study was to investigate the reaction between naproxen (NPX) and meglumine (MEG) at elevated temperature and to study the effect of this reaction on the physical stabilities and in vitro drug-release properties of melt-extruded naproxen amorphous solid dispersions (ASDs). Differential scanning calorimetry, hot-stage polarized light microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses demonstrated that in situ salt formation with proton transfer between NPX and MEG occurred at elevated temperature during the melt extrusion process. The amorphous NPX-MEG salt was physically most stable when two components were present at a 1:1 molar ratio. Polymeric carriers, including povidone, copovidone, and SOLUPLUS, did not interfere with the reaction between NPX and MEG during melt extrusion. Compared to the traditional NPX ASDs consisting of NPX and polymer only, NPX-MEG ASDs were physically more stable and remained amorphous following four months storage at 40 °C and 75% RH (relative humidity). Based on nonsink dissolution testing and polarized light microscopy analyses, we concluded that the conventional NPX ASDs composed of NPX and polymers failed to improve the NPX dissolution rate due to the rapid recrystallization of NPX in contact with aqueous medium. The dissolution rate of NPX-MEG ASDs was two times greater than the corresponding physical mixtures and conventional NPX ASDs. This study demonstrated that the acid-base reaction between NPX and MEG during melt extrusion significantly improved the physical stability and the dissolution rate of NPX ASDs.

A Taguchi approach on optimal process control parameters for HDPE pipe extrusion process

NASA Astrophysics Data System (ADS)

Sharma, G. V. S. S.; Rao, R. Umamaheswara; Rao, P. Srinivasa

2017-06-01

High-density polyethylene (HDPE) pipes find versatile applicability for transportation of water, sewage and slurry from one place to another. Hence, these pipes undergo tremendous pressure by the fluid carried. The present work entails the optimization of the withstanding pressure of the HDPE pipes using Taguchi technique. The traditional heuristic methodology stresses on a trial and error approach and relies heavily upon the accumulated experience of the process engineers for determining the optimal process control parameters. This results in setting up of less-than-optimal values. Hence, there arouse a necessity to determine optimal process control parameters for the pipe extrusion process, which can ensure robust pipe quality and process reliability. In the proposed optimization strategy, the design of experiments (DoE) are conducted wherein different control parameter combinations are analyzed by considering multiple setting levels of each control parameter. The concept of signal-to-noise ratio ( S/ N ratio) is applied and ultimately optimum values of process control parameters are obtained as: pushing zone temperature of 166 °C, Dimmer speed at 08 rpm, and Die head temperature to be 192 °C. Confirmation experimental run is also conducted to verify the analysis and research result and values proved to be in synchronization with the main experimental findings and the withstanding pressure showed a significant improvement from 0.60 to 1.004 Mpa.

The interprocess NIR sampling as an alternative approach to multivariate statistical process control for identifying sources of product-quality variability.

PubMed

Marković, Snežana; Kerč, Janez; Horvat, Matej

2017-03-01

We are presenting a new approach of identifying sources of variability within a manufacturing process by NIR measurements of samples of intermediate material after each consecutive unit operation (interprocess NIR sampling technique). In addition, we summarize the development of a multivariate statistical process control (MSPC) model for the production of enteric-coated pellet product of the proton-pump inhibitor class. By developing provisional NIR calibration models, the identification of critical process points yields comparable results to the established MSPC modeling procedure. Both approaches are shown to lead to the same conclusion, identifying parameters of extrusion/spheronization and characteristics of lactose that have the greatest influence on the end-product's enteric coating performance. The proposed approach enables quicker and easier identification of variability sources during manufacturing process, especially in cases when historical process data is not straightforwardly available. In the presented case the changes of lactose characteristics are influencing the performance of the extrusion/spheronization process step. The pellet cores produced by using one (considered as less suitable) lactose source were on average larger and more fragile, leading to consequent breakage of the cores during subsequent fluid bed operations. These results were confirmed by additional experimental analyses illuminating the underlying mechanism of fracture of oblong pellets during the pellet coating process leading to compromised film coating.

Disc extrusions and bulges in nonspecific low back pain and sciatica: Exploratory randomised controlled trial comparing yoga therapy and normal medical treatment.

PubMed

Monro, Robin; Bhardwaj, Abhishek Kumar; Gupta, Ram Kumar; Telles, Shirley; Allen, Beth; Little, Paul

2015-01-01

Previous trials of yoga therapy for nonspecific low back pain (nsLBP) (without sciatica) showed beneficial effects. To test effects of yoga therapy on pain and disability associated with lumbar disc extrusions and bulges. Parallel-group, randomised, controlled trial. Sixty-one adults from rural population, aged 20-45, with nsLBP or sciatica, and disc extrusions or bulges. Randomised to yoga (n=30) and control (n=31). Yoga: 3-month yoga course of group classes and home practice, designed to ensure safety for disc extrusions. normal medical care. OUTCOME MEASURES (3-4 months) Primary: Roland Morris Disability Questionnaire (RMDQ); worst pain in past two weeks. Secondary: Aberdeen Low Back Pain Scale; straight leg raise test; structural changes. Disc projections per case ranged from one bulge or one extrusion to three bulges plus two extrusions. Sixty-two percent had sciatica. Intention-to-treat analysis of the RMDQ data, adjusted for age, sex and baseline RMDQ scores, gave a Yoga Group score 3.29 points lower than Control Group (0.98, 5.61; p=0.006) at 3 months. No other significant differences in the endpoints occurred. No adverse effects of yoga were reported. Yoga therapy can be safe and beneficial for patients with nsLBP or sciatica, accompanied by disc extrusions and bulges.

Microstructure and Texture Evolutions of Biomedical Ti-13Nb-13Zr Alloy Processed by Hydrostatic Extrusion

NASA Astrophysics Data System (ADS)

Ozaltin, K.; Panigrahi, A.; Chrominski, W.; Bulutsuz, A. G.; Kulczyk, M.; Zehetbauer, M. J.; Lewandowska, M.

2017-11-01

A biomedical β-type Ti-13Nb-13Zr (TNZ) (wt pct) ternary alloy was subjected to severe plastic deformation by means of hydrostatic extrusion (HE) at room temperature without intermediate annealing. Its effect on microstructure, mechanical properties, phase transformations, and texture was investigated by light and electron microscopy, mechanical tests (Vickers microhardness and tensile tests), and XRD analysis. Microstructural investigations by light microscope and transmission electron microscope showed that, after HE, significant grain refinement took place, also reaching high dislocation densities. Increases in strength up to 50 pct occurred, although the elongation to fracture left after HE was almost 9 pct. Furthermore, Young's modulus of HE-processed samples showed slightly lower values than the initial state due to texture. Such mechanical properties combined with lower Young's modulus are favorable for medical applications. Phase transformation analyses demonstrated that both initial and extruded samples consist of α' and β phases but that the phase fraction of α' was slightly higher after two stages of HE.

Study on the extrusion of nickel-based spark plug electrodes by numerical simulation

NASA Astrophysics Data System (ADS)

Saby, Q.; Courbon, C.; Salvatore, F.; Fabre, D.; Romeyer, F.

2018-05-01

Interest in metal forming simulation has grown rapidly during the last decades and is now well established even in industry. It provides a flexible and relatively cheap method to perform sensitivity analyses, getting a better insight into the forming process and use it as an optimisation tool. As far as wear is concerned, numerical simulation can be seen as a relevant approach to assess the thermomechanical loadings applied to the active die surface and therefore predict their wear behaviour. In this study, a Finite-Element (FE) based model has been developed in order to investigate the cold forming process of a nickel-based sparkplug electrode. A fully thermo-mechanically coupled implicit formulation has been used in order to model the forward extrusion step with a special emphasis on the contact conditions at the workpiece-die interface. Contact pressure, relative sliding velocity and temperature profiles have been extracted versus time and qualitatively compared to the wear phenomena observed on the worn production dies.

Effect of extrusion process parameters and pregelatinized rice flour on physicochemical properties of ready-to-eat expanded snacks.

PubMed

Gat, Yogesh; Ananthanarayan, Laxmi

2015-05-01

Present study was conducted to investigate effects of pregelatinized rice flour and extrusion process parameters such as feed moisture (16-19 %), die temperature (115-145 °C) and screw speed (150-250 rpm) on physicochemical properties of ready-to-eat expanded snacks by using co-rotating twin-screw extruder. Higher die temperature increased extrudate density and WSI but reduced die pressure, torque and expansion. Increased feed moisture content resulted in extrudates with increased density, WAI and hardness but reduced die pressure, expansion and WSI. Screw speed was found to have no significant effect on expansion and hardness of extrudates, while increase in screw speed resulted in increased WAI of extrudates and reduced torque of extrudates. Effect of pregelatinized rice flour on extrudate expansion and hardness was analysed at 16 % feed moisture, 135 °C die temperature and 150 rpm screw speed. Use of pregelatinized rice flour increased expansion while it reduced hardness of extrudates.

Beyond cellular detoxification: a plethora of physiological roles for MDR transporter homologs in plants

PubMed Central

Remy, Estelle; Duque, Paula

2014-01-01

Higher plants possess a multitude of Multiple Drug Resistance (MDR) transporter homologs that group into three distinct and ubiquitous families—the ATP-Binding Cassette (ABC) superfamily, the Major Facilitator Superfamily (MFS), and the Multidrug And Toxic compound Extrusion (MATE) family. As in other organisms, such as fungi, mammals, and bacteria, MDR transporters make a primary contribution to cellular detoxification processes in plants, mainly through the extrusion of toxic compounds from the cell or their sequestration in the central vacuole. This review aims at summarizing the currently available information on the in vivo roles of MDR transporters in plant systems. Taken together, these data clearly indicate that the biological functions of ABC, MFS, and MATE carriers are not restricted to xenobiotic and metal detoxification. Importantly, the activity of plant MDR transporters also mediates biotic stress resistance and is instrumental in numerous physiological processes essential for optimal plant growth and development, including the regulation of ion homeostasis and polar transport of the phytohormone auxin. PMID:24910617

APPLICATIONS OF HOT-MELT EXTRUSION FOR DRUG DELIVERY

PubMed Central

Repka, Michael A.; Majumdar, Soumyajit; Battu, Sunil Kumar; Srirangam, Ramesh; Upadhye, Sampada B.

2018-01-01

In today’s pharmaceutical arena, it is estimated that more than 40% of new chemical entities produced during drug discovery efforts exhibit poor solubility characteristics. However, over the last decade hot-melt extrusion (HME) has emerged as a powerful processing technology for drug delivery and has opened the door to a host of such molecules previously considered unviable as drugs. HME is considered to be an efficient technique in developing solid molecular dispersions and has been demonstrated to provide sustained, modified and targeted drug delivery resulting in improved bioavailability. This article reviews the myriad of HME applications for pharmaceutical dosage forms such as tablets, capsules, films and implants for drug delivery through oral, transdermal, transmucosal, transungual, as well as other routes of administration. Interest in HME as a pharmaceutical process continues to grow and the potential of automation and reduction of capital investment and labor costs have made this technique worthy of consideration as a drug delivery solution. PMID:19040397

Impact of Processing on the Protein Quality of Pinto Bean (Phaseolus vulgaris) and Buckwheat (Fagopyrum esculentum Moench) Flours and Blends, As Determined by in Vitro and in Vivo Methodologies.

PubMed

Nosworthy, Matthew G; Franczyk, Adam; Zimoch-Korzycka, Anna; Appah, Paulyn; Utioh, Alphonsus; Neufeld, Jason; House, James D

2017-05-17

Blending of protein sources can increase protein quality by compensating for limiting amino acids present in individual sources, whereas processing grain flours by extrusion or baking can also alter protein quality. To determine the effect of baking and extrusion on the protein quality of blended flours from buckwheat and pinto beans, a rodent bioassay was performed and compared to an in vitro method of protein quality determination. Overall, extruded products had higher protein efficiency ratio values, increased digestibility, and greater protein digestibility corrected amino acid score (PDCAAS) values than baked products, with the extruded buckwheat/pinto blend having the greatest PDCAAS value of the experimental diets investigated. A correlation was found between both digestibility and PDCAAS values generated from in vitro and in vivo methods. The use of in vitro digestibility analysis should be investigated as a potential replacement for the current rodent assay for nutrient content claim purposes.

Mechanical properties and electrical conductivity of Al 6101 and 6201 alloys processed by hydro-extrusion

NASA Astrophysics Data System (ADS)

Pakiela, Z.; Ludwichowska, K.; Ferenc, J.; Kulczyk, M.

2014-08-01

The aim of this work was to produce a material with high strength and electrical conductivity. Two aluminium alloys: Al 6101 and 6201 were used for investigation. Improvement of mechanical properties was obtained by severe plastic deformation, using Hydrostatic Extrusion (HE). To examine mechanical properties of the materials microhardness and tensile tests were carried out. Furthermore, the microstructure analysis was carried out using TEM and light microscopy. Electrical conductivity of materials was measured by 4-wire method. It was found that in the material processed by HE tensile strength and microhardness increased about twice. The biggest strength of 356 MPa was obtained for alloy 6201 after HE. In this case the reduction of a diameters from 20 to 5 mm was used. Examination of the microstructure revealed that as a result of HE grain size refinement to 0.5 micrometer occurred. It was also found that the material has the electric conductivity of about 52% IACS.

Concentrations and toxicity of fumonisin B1 in fermented corn grits are reduced by extrusion cooking with glucose supplementation

USDA-ARS?s Scientific Manuscript database

Extrusion is a cooking method in which dough is forced under high pressure through a heated barrel using one (single-screw configuration) or two (twin-screw configuration) augers. In an earlier experiment (Voss et al., J. Food Protec. 71: 2036-2041, 2008), extrusion using the single screw configura...

NANEX: Process design and optimization.

PubMed

Baumgartner, Ramona; Matić, Josip; Schrank, Simone; Laske, Stephan; Khinast, Johannes; Roblegg, Eva

2016-06-15

Previously, we introduced a one-step nano-extrusion (NANEX) process for transferring aqueous nano-suspensions into solid formulations directly in the liquid phase. Nano-suspensions were fed into molten polymers via a side-feeding device and excess water was eliminated via devolatilization. However, the drug content in nano-suspensions is restricted to 30 % (w/w), and obtaining sufficiently high drug loadings in the final formulation requires the processing of high water amounts and thus a fundamental process understanding. To this end, we investigated four polymers with different physicochemical characteristics (Kollidon(®) VA64, Eudragit(®) E PO, HPMCAS and PEG 20000) in terms of their maximum water uptake/removal capacity. Process parameters as throughput and screw speed were adapted and their effect on the mean residence time and filling degree was studied. Additionally, one-dimensional discretization modeling was performed to examine the complex interactions between the screw geometry and the process parameters during water addition/removal. It was established that polymers with a certain water miscibility/solubility can be manufactured via NANEX. Long residence times of the molten polymer in the extruder and low filling degrees in the degassing zone favored the addition/removal of significant amounts of water. The residual moisture content in the final extrudates was comparable to that of extrudates manufactured without water. Copyright © 2016 Elsevier B.V. All rights reserved.

Assessment of the Relationship between the Shape of the Lateral Meniscus and the Risk of Extrusion Based on MRI Examination of the Knee Joint.

PubMed

Szarmach, Arkadiusz; Luczkiewicz, Piotr; Skotarczak, Monika; Kaszubowski, Mariusz; Winklewski, Pawel J; Dzierzanowski, Jaroslaw; Piskunowicz, Maciej; Szurowska, Edyta; Baczkowski, Bogusław

2016-01-01

Meniscus extrusion is a serious and relatively frequent clinical problem. For this reason the role of different risk factors for this pathology is still the subject of debate. The goal of this study was to verify the results of previous theoretical work, based on the mathematical models, regarding a relationship between the cross-section shape of the meniscus and the risk of its extrusion. Knee MRI examination was performed in 77 subjects (43 men and 34 women), mean age 34.99 years (range: 18-49 years), complaining of knee pain. Patients with osteoarthritic changes (grade 3 and 4 to Kellgren classification), varus or valgus deformity and past injuries of the knee were excluded from the study. A 3-Tesla MR device was used to study the relationship between the shape of the lateral meniscus (using slope angle, meniscus-cartilage height and meniscus-bone angle) and the risk of extrusion. Analysis revealed that with values of slope angle and meniscus-bone angle increasing by one degree, the risk of meniscus extrusion raises by 1.157 and 1.078 respectively. Also, an increase in meniscus-cartilage height by 1 mm significantly elevates the risk of extrusion. At the same time it was demonstrated that for meniscus-bone angle values over 42 degrees and slope angle over 37 degrees the risk of extrusion increases significantly. This was the first study to demonstrate a tight correlation between slope angle, meniscus-bone angle and meniscus-cartilage height values in the assessment of the risk of lateral meniscus extrusion. Insertion of the above parameters to the radiological assessment of the knee joint allows identification of patients characterized by an elevated risk of development of this pathology.

Medial extrusion of the posterior segment of medial meniscus is a sensitive sign for posterior horn tears.

PubMed

Ohishi, Tsuyoshi; Suzuki, Daisuke; Yamamoto, Kazufumi; Banno, Tomohiro; Shimizu, Yuta; Matsuyama, Yukihiro

2014-01-01

To evaluate medial extrusion of the posterior segment of the medial meniscus in posterior horn tears. This study enrolled 72 patients without medial meniscal tears (group N), 72 patients with medial meniscal tears without posterior horn tears (group PH-), 44 patients with posterior horn tears of the medial meniscus (group PH+). All meniscal tears were confirmed by arthroscopy. Medial extrusion of the middle segment and the posterior segment was measured on coronal MRIs. Extrusions of both middle and posterior segments in groups PH- and PH+ (middle segment; 2.94±1.51 mm for group PH- and 3.75±1.69 mm for group PH+, posterior segment; 1.85±1.82 mm for group PH- and 4.59±2.74 mm for group PH+) were significantly larger than those in group N (middle segment; 2.04±1.20, posterior segment; 1.21±1.86). Both indicators of extrusion in group PH+ were larger than those in group PH-. In the early OA category, neither middle nor posterior segment in group PH- extruded more than in group N. However, only the posterior segment in group PH+ extruded significantly more than in group N. Multiple lineal regression analyses revealed that posterior segment extrusion was strongly correlated with the posterior horn tears (p<0.001) among groups PH- and PH+. The newly presented indicator for extrusion of the posterior segment of the medial meniscus is associated with posterior horn tears in comparison with the extrusion of the middle segment, especially in the early stages of osteoarthritis. Level II--Diagnostic Study. Copyright © 2013 Elsevier B.V. All rights reserved.

Dynamic coupling among channel flow, plateau growth, foreland shortening, and the formation of metamorphic core complexes: Application to the Tibetan plateau

NASA Astrophysics Data System (ADS)

Rey, P. F.; Teyssier, C.; Whitney, D. L.

2009-04-01

Gravitational potential energy stored in an orogenic plateau can be sufficiently strong to deform the surrounding region (foreland), hence contributing to both plateau growth and collapse. Gravity-driven channel flow from the plateau lower crust into the foreland lower crust, or channel extrusion, has been proposed as a main contributor to the eastward growth of the Tibetan plateau, possibly driving the lower crust channel as far as 1000 km beneath the foreland (eg. Royden et al., 2008). On the basis of numerical modeling using temperature-dependent viscosities and densities, we show that four processes impose severe limitations to channel extrusion: (1) cooling of the extruded channel, (2) convective motion in the plateau channel, (3) surface extension of the plateau, and (4) erosion of the plateau edge. Model results show that peak velocities in the extrusion channel drop rapidly (in less than a few My) from ca. 5 cm/year to less than 1 cm/year, owing to the rapid cooling in the channel from 750-850°C to 650-550°C as it travels into the foreland region. Channel flow extrusion is further slowed when convective flow initiates in the plateau channel as a result of only a few percent drop in density. This convection inhibits laminar flow in the channel, reduces the peak horizontal velocity in the channel to a few mm, and even drives a counter flow at the base of the channel, preventing its propagation toward the foreland. If the foreland is actively pulled away from the plateau (extending boundaries), the plateau upper crust undergoes extension and the lower crust moves up efficiently into a metamorphic core complex, which inhibits flow of the channel away from the plateau and even generates a counter flow from the foreland to the metamorphic core complex. If the foreland is fixed, the same phenomenon occurs as long as the foreland upper crust undergoes shortening (likely weakened by high pore fluid pressure), which enhances extension of the plateau and upward flow of the channel. Previous studies (eg. Beaumont et al, 2001) have already emphasized the importance of aggressive erosion of the plateau edge as a process able to remove a section of the plateau upper crust, providing space for the plateau lower crust to flow into. Together, these numerical experiments demonstrate the dynamic link that exists between plateau and foreland through the behavior of a low-viscosity channel. For the cases studied, the length scale of channel extrusion is 100 km in the most favorable conditions, and not 1000 km as previously suggested. Beaumont, C., Jamieson, R.A., Nguyen, M.H. & Lee, B. Himalayan tectonics explained by extrusion of a low-viscosity crustal channel coupled to focused surface denudation. Nature 414, 738-742 (2001). Royden, L. H., Burchfiel, B.C. & van der Hilst, R.D. The geological evolution of the Tibetan Plateau. Science 321, 1054 - 1058 (2008).

Experimental Design for Evaluation of Co-extruded Refractory Metal/Nickel Base Superalloy Joints

DOE Office of Scientific and Technical Information (OSTI.GOV)

ME Petrichek

2005-12-16

Prior to the restructuring of the Prometheus Program, the NRPCT was tasked with delivering a nuclear space reactor. Potential NRPCT nuclear space reactor designs for the Prometheus Project required dissimilar materials to be in contact with each other while operating at extreme temperatures under irradiation. As a result of the high reactor core temperatures, refractory metals were the primary candidates for many of the reactor structural and cladding components. They included the tantalum-base alloys ASTAR-811C and Ta-10W, the niobium-base alloy FS-85, and the molybdenum base alloys Moly 41-47.5 Rhenium. The refractory metals were to be joined to candidate nickel basemore » alloys such as Haynes 230, Alloy 617, or Nimonic PE 16 either within the core if the nickel-base alloys were ultimately selected to form the outer core barrel, or at a location exterior to the core if the nickel-base alloys were limited to components exterior to the core. To support the need for dissimilar metal joints in the Prometheus Project, a co-extrusion experiment was proposed. There are several potential methods for the formation of dissimilar metal joints, including explosive bonding, friction stir welding, plasma spray, inertia welding, HIP, and co-extrusion. Most of these joining methods are not viable options because they result in the immediate formation of brittle intermetallics. Upon cooling, intermetallics form in the weld fusion zone between the joined metals. Because brittle intermetallics do not form during the initial bonding process associated with HIP, co-extrusion, and explosive bonding, these three joining procedures are preferred for forming dissimilar metal joints. In reference to a Westinghouse Astronuclear Laboratory report done under a NASA sponsored program, joints that were fabricated between similar materials via explosive bonding had strengths that were directly affected by the width of the diffusion barrier. It was determined that the diffusion zone should not exceed a critical thickness (0.0005 in.). A diffusion barrier that exceeded this thickness would likely fail. The joint fabrication method must therefore mechanically bond the two materials causing little or no interdiffusion upon formation. Co-extrusion fits this description since it forms a mechanical joint between two materials by using heat and pressure. The two materials to be extruded are first assembled and sealed within a co-extrusion billet which is subsequently heated and then extruded through a die. For a production application, once the joint is formed, it is dejacketed to remove the outer canister. The remaining piece consists of two materials bonded together with a thin diffusion barrier. Therefore, the long-term stability of the joint is determined primarily by the kinetics of interdiffusion reaction between the two materials. An experimental design for co-extrusion of refractory metals and nickel-based superalloys was developed to evaluate this joining process and determine the long-term stability of the joints.« less

Extrusion rate of the Mount St. Helens lava dome estimated from terrestrial imagery, November 2004-December 2005: Chapter 12 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

USGS Publications Warehouse

Major, Jon J.; Kingsbury, Cole G.; Poland, Michael P.; LaHusen, Richard G.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

2008-01-01

Oblique, terrestrial imagery from a single, fixed-position camera was used to estimate linear extrusion rates during sustained exogenous growth of the Mount St. Helens lava dome from November 2004 through December 2005. During that 14-month period, extrusion rates declined logarithmically from about 8-10 m/d to about 2 m/d. The overall ebbing of effusive output was punctuated, however, by episodes of fluctuating extrusion rates that varied on scales of days to weeks. The overall decline of effusive output and finer scale rate fluctuations correlated approximately with trends in seismicity and deformation. Those correlations portray an extrusion that underwent episodic, broad-scale stick-slip behavior superposed on the finer scale, smaller magnitude stick-slip behavior that has been hypothesized by other researchers to correlate with repetitive, nearly periodic shallow earthquakes.