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Sample records for channel angular extrusion

  1. Equal Channel Angular Extrusion Simulation of High-Nb Containing β-γ TiAl Alloys

    Directory of Open Access Journals (Sweden)

    Lai-qi Zhang

    2015-01-01

    Full Text Available TiAl alloys containing high Nb are significantly promising for high-temperature structural applications in aerospace and automotive industries. Unfortunately the low plasticity at room temperature limits their extensive applications. To improve the plasticity, not only optimizing the opposition, but also refining grain size through equal channel angular extrusion (ECAE is necessary. The equal channel angular extrusion simulation of Ti-44Al-8Nb-(Cr,Mn,B,Y(at% alloy was investigated by using the Deform-3D software. The influences of friction coefficient, extrusion velocity, and different channel angles on effective strain, damage factor, and the load on the die were analyzed. The results indicate that, with the increasing of friction coefficient, effective strain is enhanced. The extrusion velocity has little effect on the uniformity of effective strain; in contrast it has large influence on the damage factor. Thus smaller extrusion rate is more appropriate. Under the condition of different channel angles, the larger one results in the lower effective strain magnitude and better strain distribution uniformity.

  2. An investigation into the effect of equal channel angular extrusion process on mechanical and microstructural properties of middle layer in copper clad aluminum composite

    International Nuclear Information System (INIS)

    Tolaminejad, B.; Karimi Taheri, A.; Arabi, H.; Shahmiri, M.

    2009-01-01

    Equal channel angular extrusion is a promising technique for production of ultra fine-grain materials of few hundred nanometers size. In this research, the grain refinement of aluminium strip is accelerated by sandwiching it between two copper strips and then subjecting the three strips to Equal channel angular extrusion process simultaneously. The loosely packed copper-aluminium-copper laminated billet was passed through Equal channel angular extrusion die up to 8 passes using the Bc route. Then, tensile properties and some microstructural characteristics of the aluminium layer were evaluated. The scanning and transmission electron microscopes, and X-ray diffraction were used to characterize the microstructure. The results show that the yield stress of middle layer (Al) is increased significantly by about four times after application of Equal channel angular extrusion throughout the four consecutive passes and then it is slightly decreased when more Equal channel angular extrusion passes are applied. An ultra fine grain within the range of 500 to 600 nm was obtained in the Al layer by increasing the thickness of the copper layers. lt was observed that the reduction of grain size in the aluminium layer is nearly 55% more than that of a equal channel angular-extruded single layer aluminium billet, i.e. extruding a single aluminium strip or a billet without any clad for the same amount of deformation. This behaviour was attributed to the higher rates of dislocations interaction and cell formation and texture development during the Equal channel angular extrusion of the laminated composite compared to those of a single billet.

  3. Effects of equal channel angular extrusion on microstructure, strength and ballistic performance of AA5754 plates

    DEFF Research Database (Denmark)

    Mishin, Oleg; Hong, Chuanshi; Toftegaard, Helmuth Langmaack

    2014-01-01

    The microstructure, hardness, tensile properties and ballistic performance have been investigated in thick plates of the AA5754 alloy both in a coarse-grained as-received condition and after 4 passes of equal channel angular extrusion (ECAE) conducted at elevated temperatures. It is found that ECAE...

  4. Analysis of Crystallographic Textures in Aluminum Plates Processed by Equal Channel Angular Extrusion

    DEFF Research Database (Denmark)

    Li, Saiyi; Mishin, Oleg

    2014-01-01

    A modeling and experimental investigation has been conducted to explore the effect of processing route on texture evolution during equal channel angular extrusion (ECAE) of aluminum plate samples. It is found that although the textures in the plates develop along orientation fibers previously ide...... identified for ECAE-processed rods and bars, the main components and strength of these textures vary significantly with processing route, which may lead to considerable differences in the plastic anisotropy of the plates....

  5. Equal-channel angular sheet extrusion of interstitial-free (IF) steel: Microstructural evolution and mechanical properties

    International Nuclear Information System (INIS)

    Saray, O.; Purcek, G.; Karaman, I.; Neindorf, T.; Maier, H.J.

    2011-01-01

    Highlights: → IF-steel sheets can successfully be processed in the continuous manner using the equal-channel angular sheet extrusion (ECASE). → The ECASE produces the microstructures including dislocation cell and micro-shear bands inside the grains with mainly low-angle grain boundaries. → The ECASE results in a considerable increase in the strength but limited ductility. → A good strength-ductility balance in the ECASE-processed IF-steel sheets can be managed with a suitable annealing parameters. - Abstract: Interstitial-free steel (IF-steel) sheets were processed at room temperature using a continuous severe plastic deformation (SPD) technique called equal-channel angular sheet extrusion (ECASE). After processing, the microstructural evolution and mechanical properties have been systematically investigated. To be able to directly compare the results with those from the same material processed using discontinuous equal channel angular extrusion, the sheets were ECASE processed up to eight passes. The microstructural investigations revealed that the processed sheets exhibited a dislocation cell and/or subgrain structures with mostly low angle grain boundaries. The grains after processing have relatively high dislocation density and intense micro-shear band formation. The electron backscattering diffraction (EBSD) examination showed that the processed microstructure is not fully homogeneous along the sheet thickness due probably to the corner angle of 120 deg. in the ECASE die. It was also observed that the strengths of the processed sheets increase with the number of ECASE passes, and after eight passes following route-A and route-C, the yield strengths reach 463 MPa and 459 MPa, respectively, which is almost 2.5 times higher than that of the initial material. However, the tensile ductility considerably dropped after the ECASE. The limited ductility was attributed to the early plastic instability in the tensile samples due to the inhomogeneous

  6. An investigation on diffusion bonding of aluminum to copper using equal channel angular extrusion process

    OpenAIRE

    Eslami, P.; Taheri, A. Karimi

    2011-01-01

    A new method for production of bimetallic rods, utilizing the equal channel angular extrusion (ECAE) process has been introduced before by previous researchers, but no attempt has been made to assess the effect of different temperatures and holding times in order to achieve a diffusional bond between the mating surfaces. In present research copper sheathed aluminum rods have been ECAEed at room temperature and subsequently held at a constant ECAE pressure, at different temperatures and holdin...

  7. Quantitative Microstructural Characterization of Thick Aluminum Plates Heavily Deformed Using Equal Channel Angular Extrusion

    DEFF Research Database (Denmark)

    Mishin, Oleg; Segal, V.M.; Ferrasse, S.

    2012-01-01

    A detailed quantitative analysis of the microstructure has been performed in three orthogonal planes of 15-mm-thick aluminum plates heavily deformed via two equal channel angular extrusion (ECAE) routes. One route was a conventional route A with no rotation between passes. Another route involved...... sequential 90 deg rotations about the normal direction (ND) between passes. The microstructure in the center of these plates, and especially the extent of microstructural heterogeneity, has been characterized quantitatively and compared with that in bar samples extruded via either route A or route Bc with 90...... Bc. © The Minerals, Metals & Materials Society and ASM International 2012...

  8. CHARACTERIZATION OF THE GRAINS IN 2014 ALUMINIUM ALLOY AFTER EQUAL CHANNEL ANGULAR EXTRUSION (ECAE PROCESS

    Directory of Open Access Journals (Sweden)

    Sonia Boczkal

    2011-05-01

    Full Text Available In 2014 alloy deformed by Equal Channel Angular Extrusion process (ECAE the changes in the size and shape of structural constituents were examined. The samples subjected after deformation to additional annealing at 300°C/10min were characterized by larger grains of nearly-equiaxial shapes. The microstructure after deformation was composed of a large number of the mutually crossing bands and microbands. The intersection of microbands resulted in formation of rectangular and rhombohedral grains. It was noted that the average grain size after ε = 4.6 (4 passes was 0.2 μm.

  9. Equal channel angular extrusion of ultra-high molecular weight polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Reinitz, Steven D., E-mail: Steven.D.Reinitz.TH@Dartmouth.edu; Engler, Alexander J.; Carlson, Evan M.; Van Citters, Douglas W.

    2016-10-01

    Ultra-high molecular weight polyethylene (UHMWPE), a common bearing surface in total joint arthroplasty, is subject to material property tradeoffs associated with conventional processing techniques. For orthopaedic applications, radiation-induced cross-linking is used to enhance the wear resistance of the material, but cross-linking also restricts relative chain movement in the amorphous regions and hence decreases toughness. Equal Channel Angular Extrusion (ECAE) is proposed as a novel mechanism by which entanglements can be introduced to the polymer bulk during consolidation, with the aim of imparting the same tribological benefits of conventional processing without complete inhibition of chain motion. ECAE processing at temperatures near the crystalline melt for UHMWPE produces (1) increased entanglements compared to control materials; (2) increasing entanglements with increasing temperature; and (3) mechanical properties between values for untreated polyethylene and for cross-linked polyethylene. These results support additional research in ECAE-processed UHMWPE for joint arthroplasty applications. - Highlights: • A new processing method for ultra-high molecular weight polyethylene is introduced. • The process produces a highly entangled polyethylene material. • Entanglements are hypothesized to enhance the wear resistance of polyethylene. • This process eliminates the trade-off between mechanical and wear properties.

  10. Numerical Investigation of Plastic Deformation in Two-turn Equal Channel Angular Extrusion

    Directory of Open Access Journals (Sweden)

    A. Mitsak

    2014-12-01

    Full Text Available There has been a number of investigations in recent years reporting on the structure and properties of materials deformed to super plastic deformation (SPD. During SPD new textures can be formed and abnormal characteristics are displayed, attracting a growing research interest.¶ Equal channel angular extrusion (ECAE is a method often used to obtain large plastic strains. However, according to experimental results, there is a large tensile stress in the sample during deformation, which may lead in some cases, to cracking in metallic alloys and large curvature in polymeric materials. In order to overcome these drawbacks, the ECAE process can be conducted at high temperatures. But this contributes significantly to a decreased level of plastic deformation induced in the sample. Hence, a tool with multi-pass seems to be a very appropriate solution. In this paper, a new geometry die composed of two elbows has been simulated by finite element method aiming to provide an insight into the mechanisms of deformation and to determine the optimum geometry of the tool. The numerical results show that the length and the section of the second channel play a significant role on the homogeneity of the plastic strain distribution. It has been found that good homogeneity was obtained when the second channel has the same section as that of the entrance and the exit channels and with a length equal to three times of its width.

  11. Scale up and application of equal-channel angular extrusion for the electronics and aerospace industries

    International Nuclear Information System (INIS)

    Ferrasse, Stephane; Segal, V.M.; Alford, Frank; Kardokus, Janine; Strothers, Susan

    2008-01-01

    Two areas are critical to promote equal-channel angular extrusion beyond the stage of a laboratory curiosity: (i) tool/processing design and scale up; (ii) development of new submicrometer-grained products. Both goals are pursued at Honeywell. The first case is the successful commercialization of ECAE for the production of sputtering targets from single phase alloys in the electronic industry. Blank dimensions are significantly larger than those reported in the literature. Other described applications are targeted to the increase of tensile strength, high-cycle fatigue and toughness in medium-to-heavily alloyed Al materials used in aerospace. In these alloys, the optimal properties can be reached with better understanding of the interplay between plastic deformation and precipitation mechanisms

  12. Microstructure and mechanical properties of Al-3Fe alloy processed by equal channel angular extrusion

    International Nuclear Information System (INIS)

    Fuxiao, Yu; Fang, Liu; Dazhi, Zhao; Toth, Laszlo S

    2014-01-01

    Al-Fe alloys are attractive for applications at temperatures beyond those normally associated with the conventional aluminum alloys. Under proper solidification condition, a full eutectic microstructure can be generated in Al-Fe alloys at Fe concentration well in excess of the eutectic composition of 1.8 wt.% Fe. The microstructure in this case is characterized by the metastable regular eutectic Al-Al 6 Fe fibers of nano-scale in diameter, instead of the equilibrium eutectic Al-Al 3 Fe phase. In this study, the microstructure and mechanical properties of the Al-3Fe alloy with metastable Al 6 Fe particles deformed by equal channel angular extrusion were investigated. Severe plastic deformation results in a microstructure consisting of submicron equiaxed Al grains with a uniform distribution of submicron Al 6 Fe particles on the grain boundaries. The room temperature tensile properties of the alloy with this microstructure will be presented

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

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, X.G.; Ying, T. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zheng, M.Y., E-mail: zhenghe@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wei, E.D.; Wu, K.; Hu, X.S. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Gan, W.M.; Brokmeier, H.G. [Institute of Materials Research, Helmholtz-Centre Geesthacht, D-21502 Geesthacht (Germany); Golovin, I.S. [Department of Physical Metallurgy of Non-Ferrous Metals, National University of Science and Technology “MISiS”, Leninsky ave. 4, 119049 Moscow (Russian Federation)

    2016-11-15

    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 agglomerated 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.

  14. An electron back-scattered diffraction study on the microstructure evolution of AZ31 Mg alloy during equal channel angular extrusion

    International Nuclear Information System (INIS)

    Jin Li; Lin Dongliang; Mao Dali; Zeng Xiaoqin; Ding Wenjiang

    2006-01-01

    Microstructure evolution of AZ31 Mg alloy during equal channel angular extrusion (ECAE) was investigated by electron back-scattered diffraction (EBSD). The grains of AZ31 Mg alloy were refined significantly after ECAE 1-8 passes at 498 K and the distributions of grain size tended to be more uniform with pass number increasing. Frequency of sub-boundaries and low angle grain boundaries (LAGBs) increased at initial stage of deformation, and sub-boundaries and LAGBs evolved into high angle grain boundaries (HAGBs) with further deformation, which resulted in the high frequency of HAGBs in the alloy after ECAE 8 passes. Preferred misorientation angle with frequency peak near 30 deg. and 90 deg. were observed. The frequency peaks were weak after ECAE 1 pass but became stronger with the increase of pass numbers. Micro-textures were formed in AZ31 microstructure during ECAE and were stronger with the pass number increasing

  15. Wear Behavior and Microstructure of Mg-Sn Alloy Processed by Equal Channel Angular Extrusion.

    Science.gov (United States)

    Chen, Jung-Hsuan; Shen, Yen-Chen; Chao, Chuen-Guang; Liu, Tzeng-Feng

    2017-11-16

    Mg-5wt.% Sn alloy is often used in portable electronic devices and automobiles. In this study, mechanical properties of Mg-5wt.% Sn alloy processed by Equal Channel Angular Extrusion (ECAE) were characterized. More precisely, its hardness and wear behavior were measured using Vickers hardness test and a pin-on-disc wear test. The microstructures of ECAE-processed Mg-Sn alloys were investigated by scanning electron microscope and X-ray diffraction. ECAE process refined the grain sizes of the Mg-Sn alloy from 117.6 μm (as-cast) to 88.0 μm (one pass), 49.5 μm (two passes) and 24.4 μm (four passes), respectively. Meanwhile, the hardness of the alloy improved significantly. The maximum wear resistance achieved in the present work was around 73.77 m/mm³, which was obtained from the Mg-Sn alloy treated with a one-pass ECAE process with a grain size of 88.0 μm. The wear resistance improvement was caused by the grain size refinement and the precipitate of the second phase, Mg₂Sn against the oxidation of the processed alloy. The as-cast Mg-Sn alloy with the larger grain size, i.e., 117.6 μm, underwent wear mechanisms, mainly adhesive wear and abrasive wear. In ECAE-processed Mg-Sn alloy, high internal energy occurred due to the high dislocation density and the stress field produced by the plastic deformation, which led to an increased oxidation rate of the processed alloy during sliding. Therefore, the oxidative wear and a three-body abrasive wear in which the oxide debris acted as the three-body abrasive components became the dominant factors in the wear behavior, and as a result, reduced the wear resistance in the multi-pass ECAE-processed alloy.

  16. Experimental investigation on the performance of an improved equal channel angular pressing die

    International Nuclear Information System (INIS)

    Surendarnath, S; Sankaranarayanasamy, K; Ravisankar, B

    2014-01-01

    A major problem in Equal Channel Angular Pressing is die design. Friction plays an important role in the extrusion process. In the present work, Aluminium 6082 alloy was processed through a modified ECAP die originally proposed by Mathieu et al. in 2004 [1] and the performance of the die was analyzed. The channel angle was φ=90° and corner angle ψ=20°. Mechanical properties, micro hardness measurement and crystalline size (D) were measured from the extruded specimen for both the conventional and new die designs. It has been found that the new die samples displayed better results than the conventional ones. The newly designed die reduced the effect of friction on the work piece, it increased the tensile strength, the hardness of the material and achieved better grain refinement

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

    Science.gov (United States)

    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.

  18. Improvement of Strength and Energy Absorption Properties of Porous Aluminum Alloy with Aligned Unidirectional Pores Using Equal-Channel Angular Extrusion

    Science.gov (United States)

    Yoshida, Tomonori; Muto, Daiki; Tamai, Tomoya; Suzuki, Shinsuke

    2018-06-01

    Porous aluminum alloy with aligned unidirectional pores was fabricated by dipping A1050 tubes into A6061 semi-solid slurry. The porous aluminum alloy was processed through Equal-channel Angular Extrusion (ECAE) while preventing cracking and maintaining both the pore size and porosity by setting the insert material and loading back pressure. The specific compressive yield strength of the sample aged after 13 passes of ECAE was approximately 2.5 times higher than that of the solid-solutionized sample without ECAE. Both the energy absorption E V and energy absorption efficiency η V after four passes of ECAE were approximately 1.2 times higher than that of the solid-solutionized sample without ECAE. The specific yield strength was improved via work hardening and precipitation following dynamic aging during ECAE. E V was improved by the application of high compressive stress at the beginning of the compression owing to work hardening via ECAE. η V was improved by a steep increase of stress at low compressive strain and by a gradual increase of stress in the range up to 50 pct of compressive strain. The gradual increase of stress was caused by continuous shear fracture in the metallic part, which was due to the high dislocation density and existence of unidirectional pores parallel to the compressive direction in the structure.

  19. Improvement of Strength and Energy Absorption Properties of Porous Aluminum Alloy with Aligned Unidirectional Pores Using Equal-Channel Angular Extrusion

    Science.gov (United States)

    Yoshida, Tomonori; Muto, Daiki; Tamai, Tomoya; Suzuki, Shinsuke

    2018-04-01

    Porous aluminum alloy with aligned unidirectional pores was fabricated by dipping A1050 tubes into A6061 semi-solid slurry. The porous aluminum alloy was processed through Equal-channel Angular Extrusion (ECAE) while preventing cracking and maintaining both the pore size and porosity by setting the insert material and loading back pressure. The specific compressive yield strength of the sample aged after 13 passes of ECAE was approximately 2.5 times higher than that of the solid-solutionized sample without ECAE. Both the energy absorption E V and energy absorption efficiency η V after four passes of ECAE were approximately 1.2 times higher than that of the solid-solutionized sample without ECAE. The specific yield strength was improved via work hardening and precipitation following dynamic aging during ECAE. E V was improved by the application of high compressive stress at the beginning of the compression owing to work hardening via ECAE. η V was improved by a steep increase of stress at low compressive strain and by a gradual increase of stress in the range up to 50 pct of compressive strain. The gradual increase of stress was caused by continuous shear fracture in the metallic part, which was due to the high dislocation density and existence of unidirectional pores parallel to the compressive direction in the structure.

  20. Effect of Equal Channel Angular Pressing on the Surface Roughness of Solid State Recycled Aluminum Alloy 6061 Chips

    Directory of Open Access Journals (Sweden)

    Adel Taha Abbas

    2017-01-01

    Full Text Available Solid state recycling through hot extrusion is a promising technique to recycle machining chips without remelting. Furthermore, equal channel angular pressing (ECAP technique coupled with the extruded recycled billet is introduced to enhance the mechanical properties of recycled samples. In this paper, the surface roughness of solid state recycled aluminum alloy 6061 turning chips was investigated. Aluminum chips were cold compacted and hot extruded under an extrusion ratio (ER of 5.2 at an extrusion temperature (ET of 425°C. In order to improve the properties of the extruded samples, they were subjected to ECAP up to three passes at room temperature using an ECAP die with a channel die angle (Φ of 90°. Surface roughness (Ra and Rz of the processed recycled billets machined by turning was investigated. Box-Behnken experimental design was used to investigate the effect of three machining parameters (cutting speed, feed rate, and depth of cut on the surface roughness of the machined specimens for four materials conditions, namely, extruded billet and postextrusion ECAP processed billets to one, two, and three passes. Quadratic models were developed to relate the machining parameters to surface roughness, and a multiobjective optimization scheme was conducted to maximize material removal rate while maintaining the roughness below a preset practical value.

  1. Effect of ECAP and extrusion on particle distribution in Al-nano ...

    Indian Academy of Sciences (India)

    Administrator

    Al-nano–Al2O3 composite. R DERAKHSHANDEH HAGHIGHI. Department of Materials Science and Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran. MS received 24 January 2014; accepted 23 April 2015. Abstract. In this study equal channel angular pressing (ECAP) and conventional extrusion were used ...

  2. Thermal Stability of AA1050 Aluminum Alloy after Equal Channel Angular Pressing

    Directory of Open Access Journals (Sweden)

    Koprowski P.

    2017-06-01

    Full Text Available The annealing behavior of AA1050 aluminum alloy deformed by equal-channel angular pressing (ECAP was studied experimentally. The material was subjected to extrusion through die with channels intersecting at an 90° angle. Samples were pressed for up to 8 passes using route BC, then cut into slices and subsequently annealed for 1 hour at temperatures from 100°C to 350°C. Hardness measurements were performed on each slice. Microstructure of material was analyzed in the longitudinal section by means of Electron Backscatter Diffraction system in a scanning electron microscope (EBSD/SEM. From the obtained sets of Kikuchi diffraction patterns orientation maps and Image Quality maps were determined. Grain size, disorientation distributions and crystallographic texture were also estimated. ECAP caused significant improvement of hardness, with stabilization after 4 passes. Refinement of microstructure was obtained with the increasing amount of passes. Material properties were stable during annealing at temperatures lower than 150°C. Annealing at higher temperatures caused a decrease in hardness corresponding to an increase of the grain size.

  3. Angular distributions of ions channeled in the Si crystals

    International Nuclear Information System (INIS)

    Petrovic, S.; Korica, S.; Kokkoris, M.; Neskovic, N.

    2002-01-01

    In this study we analyze the angular distributions of Ne 10+ ions channeled in the Si crystals. The ion energy is 60 MeV and the crystal thickness is varied from 286 to 3435 nm. This thickness range corresponds to the reduced crystal thickness range from 0.5 to 6, i.e. from the second to the twelfth rainbow cycle. The angular distributions were obtained via the numerical solution of the ion equations of motion and the computer simulation method. The analysis shows that the angular distribution has a periodic behavior. We also analyze the transmission patterns corresponding to the angular distributions. These patterns should be compared to the experimental patterns obtainable by a two-dimensional position sensitive detector. We demonstrate that, when the ion beam divergence is sufficiently large, i.e. much larger than the critical angle for channeling, the channeling star effect occurs in the transmission patterns

  4. On Angular Sampling Methods for 3-D Spatial Channel Models

    DEFF Research Database (Denmark)

    Fan, Wei; Jämsä, Tommi; Nielsen, Jesper Ødum

    2015-01-01

    This paper discusses generating three dimensional (3D) spatial channel models with emphasis on the angular sampling methods. Three angular sampling methods, i.e. modified uniform power sampling, modified uniform angular sampling, and random pairing methods are proposed and investigated in detail....... The random pairing method, which uses only twenty sinusoids in the ray-based model for generating the channels, presents good results if the spatial channel cluster is with a small elevation angle spread. For spatial clusters with large elevation angle spreads, however, the random pairing method would fail...... and the other two methods should be considered....

  5. Strain Mapping and Nanocrystallite Size Determination by Neutron Diffraction in an Aluminum Alloy (AA5083 Severely Plastically Deformed through Equal Channel Angular Pressing

    Directory of Open Access Journals (Sweden)

    P. A. González Crespo

    2013-01-01

    Full Text Available Six specimens of an aluminum alloy (AA-5083 extruded by Equal Channel Angular Pressing following two different routes plus a blank sample were examined with a neutron radiation of 1.5448 Å. Macrostrain maps from the (311 reflection were obtained. A clear difference about accumulated macrostrain with the extrusion cycles between the two routes is shown. The diffraction data of annealed specimens did permit to estimate crystallite sizes that range between 89 nm and 115 nm depending on the routes.

  6. Electron angular distribution axial channeling

    International Nuclear Information System (INIS)

    Khokonov, A.Kh.; Khokonov, M.Kh.

    1989-01-01

    Angular distributions of ultra-relativistic electrons are calculated in the assumption about presence of statistical equilibrium. Analysis is based on numerical solution of Fokker-Planck type kinetic equation. It is shown that in contrast to case of amorphous medium, the multiple scattering at axial channeling of negative particles results in self-focusing of the initial beam particles and due to it number of electrons moving at an angles to the chain, which are smaller, than critical angle of channeling, may increase by several times as compared to the initial one

  7. The effect of grain size on dynamic tensile extrusion behaviour

    Directory of Open Access Journals (Sweden)

    Park Leeju

    2015-01-01

    Full Text Available Dynamic tensile extrusion (DTE tests were conducted on coarse grained and ultrafine grained (UFG OFHC Cu, Interstitial free (IF Steel, and pure Ta. Equal channel angular pressing (ECAP of 16passes with Bc for Cu, IF Steel and 4 passes for Ta was employed to fabricated UFG materials. DTE tests were carried out by launching the sphere samples (Dia. 7.62 mm to the conical extrusion die at a speed of ∼500 m/sec. The fragmentation behavior of the soft-recovered fragments were examined and compared with each other. The DTE fragmentation behavior of CG and UFG was numerically simulated by the LS-DYNA FEM code.

  8. Microstructural evolution of bainitic steel severely deformed by equal channel angular pressing.

    Science.gov (United States)

    Nili-Ahmadabadi, M; Haji Akbari, F; Rad, F; Karimi, Z; Iranpour, M; Poorganji, B; Furuhara, T

    2010-09-01

    High Si bainitic steel has been received much of interest because of combined ultra high strength, good ductility along with high wear resistance. In this study a high Si bainitic steel (Fe-0.22C-2.0Si-3.0Mn) was used with a proper microstructure which could endure severe plastic deformation. In order to study the effect of severe plastic deformation on the microstructure and properties of bainitic steel, Equal Channel Angular Pressing was performed in two passes at room temperature. Optical, SEM and TEM microscopies were used to examine the microstructure of specimens before and after Equal Channel Angular Pressing processing. X-ray diffraction was used to measure retained austenite after austempering and Equal Channel Angular Pressing processing. It can be seen that retained austenite picks had removed after Equal Channel Angular Pressing which could attributed to the transformation of austenite to martensite during severe plastic deformation. Enhancement of hardness values by number of Equal Channel Angular Pressing confirms this idea.

  9. Microstructure and mechanical properties of carbon nanotubes reinforced aluminum matrix composites synthesized via equal-channel angular pressing

    Energy Technology Data Exchange (ETDEWEB)

    Zare, Hassan [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Jahedi, Mohammad, E-mail: mohammad.jahedi@unh.edu [Department of Mechanical Engineering, University of New Hampshire, Durham, NH 03824 (United States); Toroghinejad, Mohammad Reza; Meratian, Mahmoud [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Knezevic, Marko [Department of Mechanical Engineering, University of New Hampshire, Durham, NH 03824 (United States)

    2016-07-18

    In this work, 2 vol% carbon nanotubes (CNTs) reinforced aluminum (Al) matrix composites of superior microstructural homogeneity are successfully synthesized using Bc equal-channel angular extrusion (ECAP) route. The key step in arriving at high level of homogeneous distribution of CNTs within Al was preparation of the powder using simultaneous attrition milling and ultra-sonication processes. Microstructure as revealed by electron microscopy and absence of Vickers hardness gradients across the material demonstrate that the material reached the homogeneous state in terms of CNT distribution, porosity distribution, and grain structure after eight ECAP passes. To facilitate comparison of microstructure and hardness, samples of Al were processed under the same ECAP conditions. Significantly, the composite containing only 2 vol% exhibits 20% increase in hardness relative to the Al samples.

  10. Modeling channel interference in an orbital angular momentum-multiplexed laser link

    Science.gov (United States)

    Anguita, Jaime A.; Neifeld, Mark A.; Vasic, Bane V.

    2009-08-01

    We study the effects of optical turbulence on the energy crosstalk among constituent orbital angular momentum (OAM) states in a vortex-based multi-channel laser communication link and determine channel interference in terms of turbulence strength and OAM state separation. We characterize the channel interference as a function of C2n and transmit OAM state, and propose probability models to predict the random fluctuations in the received signals for such architecture. Simulations indicate that turbulence-induced channel interference is mutually correlated across receive channels.

  11. Angular Domain Data-Assisted Channel Estimation for Pilot Decontamination in Massive MIMO

    Directory of Open Access Journals (Sweden)

    Yihenew Beyene

    2017-01-01

    Full Text Available Massive Multiple-Input-Multiple-Output (M-MIMO system is a promising technology that offers to mobile networks substantial increase in throughput. In Time-Division Duplexing (TDD, the uplink training allows a Base Station (BS to acquire Channel State Information (CSI for both uplink reception and downlink transmission. This is essential for M-MIMO systems where downlink training pilots would consume large portion of the bandwidth. In densely populated areas, pilot symbols are reused among neighboring cells. Pilot contamination is the fundamental bottleneck on the performance of M-MIMO systems. Pilot contamination effect in antenna arrays can be mitigated by treating the channel estimation problem in angular domain where channel sparsity can be exploited. In this paper, we introduce a codebook that projects the channel into orthogonal beams and apply Minimum Mean-Squared Error (MMSE criterion to estimate the channel. We also propose data-aided channel covariance matrix estimation algorithm for angular domain MMSE channel estimator by exploiting properties of linear antenna array. The algorithm is based on simple linear operations and no matrix inversion is involved. Numerical results show that the algorithm performs well in mitigating pilot contamination where the desired channel and other interfering channels span overlapping angle-of-arrivals.

  12. Equal channel angular pressing of pure aluminium—an analysis

    Indian Academy of Sciences (India)

    Abstract. Equal channel angular pressing (ECAP) is a novel technique for producing ultra fine grain struc- tures in submicron level by introducing a large amount of shear strain into the materials without changing the billet shape or dimensions. This process is well suited for aluminium alloys and is capable of producing ultra.

  13. Microstructure and texture evolution in a Cu–Ni–Si alloy processed by equal-channel angular pressing

    Energy Technology Data Exchange (ETDEWEB)

    Hadj Larbi, Fayçal; Azzeddine, Hiba [Faculté de Physique, USTHB, BP 32 El-Alia, Dar El Beida, Alger (Algeria); Baudin, Thierry [Université de Paris Sud, ICMMO, UMR CNRS 8182, Laboratoire de physico-chimie de l’état solide, Bâtiment 410, 91405 Orsay Cedex (France); Mathon, Marie-Hélène [Laboratoire Léon Brillouin, CEA-CNRS, CEA/Saclay, 91191 Gif-sur-Yvette (France); Brisset, François; Helbert, Anne-Laure [Université de Paris Sud, ICMMO, UMR CNRS 8182, Laboratoire de physico-chimie de l’état solide, Bâtiment 410, 91405 Orsay Cedex (France); Kawasaki, Megumi, E-mail: megumi@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Departments of Aerospace & Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States); Bradai, Djamel [Faculté de Physique, USTHB, BP 32 El-Alia, Dar El Beida, Alger (Algeria); Langdon, Terence G. [Departments of Aerospace & Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States); Materials Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom)

    2015-07-25

    Highlights: • A Cu–Ni–Si alloy is processed by ECAP up to 12 passes at 423 K through route A. • The texture after ECAP is characterized by typical shear components of fcc metals. • ECAP leads to randomization of the texture with increasing numbers of passes. • ECAP through route A rotates the texture positions from the ideal component. - Abstract: Experiments were conducted to evaluate the evolution of microstructure and texture in a commercial Cu–2.5Ni–0.6Si (wt.%) alloy processed by equal-channel angular pressing (ECAP) at 423 K for up to 12 passes. An electron backscatter diffraction (EBSD) analysis shows that ECAP processing leads to microstructural refinement with an average grain size of ∼0.9 μm. The refined grains are inclined to the direction of extrusion and the deformation structure evolves from elongated grains to a duplex microstructure of equiaxed and elongated grains. Detailed measurements demonstrate that the grain boundary misorientations gradually increase with increasing numbers of ECAP passes. The texture was investigated using both EBSD and neutron diffraction. The results show the texture after ECAP is characterized by typical shear components of face-centered cubic metals which deviate from their ideal positions.

  14. Microstructure and texture evolution in a Cu–Ni–Si alloy processed by equal-channel angular pressing

    International Nuclear Information System (INIS)

    Hadj Larbi, Fayçal; Azzeddine, Hiba; Baudin, Thierry; Mathon, Marie-Hélène; Brisset, François; Helbert, Anne-Laure; Kawasaki, Megumi; Bradai, Djamel; Langdon, Terence G.

    2015-01-01

    Highlights: • A Cu–Ni–Si alloy is processed by ECAP up to 12 passes at 423 K through route A. • The texture after ECAP is characterized by typical shear components of fcc metals. • ECAP leads to randomization of the texture with increasing numbers of passes. • ECAP through route A rotates the texture positions from the ideal component. - Abstract: Experiments were conducted to evaluate the evolution of microstructure and texture in a commercial Cu–2.5Ni–0.6Si (wt.%) alloy processed by equal-channel angular pressing (ECAP) at 423 K for up to 12 passes. An electron backscatter diffraction (EBSD) analysis shows that ECAP processing leads to microstructural refinement with an average grain size of ∼0.9 μm. The refined grains are inclined to the direction of extrusion and the deformation structure evolves from elongated grains to a duplex microstructure of equiaxed and elongated grains. Detailed measurements demonstrate that the grain boundary misorientations gradually increase with increasing numbers of ECAP passes. The texture was investigated using both EBSD and neutron diffraction. The results show the texture after ECAP is characterized by typical shear components of face-centered cubic metals which deviate from their ideal positions

  15. Processing of Polypropylene-Organic Montmorillonite Nanocomposite by Equal Channel Multiangular Extrusion

    Directory of Open Access Journals (Sweden)

    V. A. Beloshenko

    2016-01-01

    Full Text Available By the example of polypropylene-organic montmorillonite composite (PP-OMMT, the abilities of the method of equal channel multiangular extrusion have been studied with respect to the modification of the structure and the properties of polymeric nanocomposites. With using X-ray structure analysis, TEM, DSC, and dilatometry, it has been demonstrated that this kind of processing provides an additional intercalation of the polymer into OMMT tactoids with the succeeding exfoliation and facilitates an increase in the aspect ratio, the degree of platelet orientation, the crystalline lamellar thickness, and a decrease in the dispersion of the crystallite thickness, as well as the formation of biaxial orientation of the OMMT and PP crystals. The observed structure rearrangements determine enhanced microhardness, ductility, and the heat distortion temperature of the PP-OMMT composite.

  16. Optimasi Proses Multi-Pass Equal Channel Angular Pressing Dengan Simulasi Komputer

    OpenAIRE

    Choiron, Moch. Agus; Anam, Khairul; Prasetyo, Totok Tri

    2014-01-01

    UFG (Ultra-fine grained) material is a material with a grain size between 10 nm to 1000 nm were developed to improve the quality of the material microstructure byreducing the grain size. Equal Channel Angular Pressing (ECAP) is a method to produce the UFG material by utilizing the shear stress on the material. Shear stress distribution in the material as it passes through the channel intersection is important to investigate so that it can be known the die design that can produce a uniform sh...

  17. Microstructure and mechanical properties of AZ91 tubes fabricated by Multi-pass Parallel Tubular Channel Angular Pressing

    OpenAIRE

    Hooman Abdolvand; Ghader Faraji; Javad Shahbazi Karami

    2017-01-01

    Parallel Tubular Channel Angular Pressing (PTCAP) process is a novel recently developed severe plastic deformation (SPD) method for producing ultrafine grained (UFG) and nanograined (NG) tubular specimens with excellent mechanical and physical properties. This process has several advantageous compared to its TCAP counterparts. In this paper, a fine grained AZ91 tube was fabricated via multi pass parallel tubular channel angular pressing (PTCAP) process. Tubes were processed up to three passes...

  18. Mechanical properties of copper processed by Equal Channel Angular Pressing - a review

    Czech Academy of Sciences Publication Activity Database

    Kunz, Ludvík; Collini, L.

    -, č. 19 (2012), s. 61-75 ISSN 1971-8993 R&D Projects: GA ČR GAP108/10/2001 Institutional research plan: CEZ:AV0Z20410507 Keywords : ultrafine-grained structure * equal channel angular pressing * copper * fatigue Subject RIV: JL - Materials Fatigue , Friction Mechanics

  19. Angular distributions of 250 GeV/c positive particles axially channeled in germanium crystal. Pt. 3

    International Nuclear Information System (INIS)

    Sun, C.R.; Gibson, W.M.; Kim, I.J.; Williams, G.O.; Carrigan, R.A. Jr.; Chrisman, B.L.; Toohig, T.E.; Guzik, Z.; Nigmanov, T.S.; Tsyganov, A.S.

    1982-01-01

    Channeling phenomena are observed for charged particles of momentum up to 250 GeV/c in a germanium crystal. The angular distributions of the channeled particles are compared with theoretical predictions based on a diffusion model. The results indicate additional mechanisms leading to dechanneling of the particles although channeling effects are observed for particles incident at up to several times the critical angle, in contrast with the results from low energy channeling. (orig.)

  20. Mechanical properties of copper processed by Equal Channel Angular Pressing – a review

    Directory of Open Access Journals (Sweden)

    Ludvík Kunz

    2012-01-01

    Full Text Available The Equal Channel Angular Pressing is a hardening treatment with which ductile metals can be processed to refine their grain and sub-grain structure. This process enhances the mechanical strength of metals in terms of tensile strength, stress-controlled fatigue strength, and fatigue crack growth resistance. In this paper the authors draw a review of the major results of a wide research activity they carried out on a copper microstructure processed by Equal Channel Angular Pressing. The essential results are that tensile and fatigue strengths of the so obtained refined structure are improved by a factor of two with respect to the original coarse-grained metal. The fatigue crack initiation mechanism and the stability of the refined microstructure under cyclic loading are topics also discussed, evidencing the essential role of the process and of the material parameter, as the content of impurities in the microstructure. In this review, the authors also underline some critical aspects that have to be more investigated.

  1. Preequilibrium GDR excitation and entrance channel angular momentum effects

    International Nuclear Information System (INIS)

    Sandoli, M.; Campajola, L.; De Rosa, A.; D'Onofrio, A.; La Commara, M.; Ordine, A.; Pierroutsakou, D.; Roca, V.; Romano, M.; Romoli, M.; Terrasi, F.; Trotta, M.; Cardella, G.; Papa, M.; Pappalardo, G.; Rizzo, F.; Alamanos, N.; Auger, F.; Gillibert, A.

    1997-01-01

    The energy spectra of the γ-rays emitted in the 35 Cl+ 92 Mo reaction at incident energy E=260 MeV were measured in coincidence with the ejectiles produced in dissipative reaction events. The cumulative energy spectrum of the γ-rays coming from the decay of the ejectiles was calculated within the statistical model and its comparison to the experimental spectrum evidences an excess in the data for E γ =8 to 12 MeV. Such an excess, fitted with a Lorentz curve, is attributed to the preequilibrium GDR γ-decay of the intermediate dinuclear system. The centroid energy of the Lorentz curve corresponds to a dipole oscillation along the symmetry axis of the system and its width is found to be comparable to that of the ground state GDR low energy component of the deformed dinucleus. The small quantal dispersion Δl=(10.3±0.1)ℎ of the entrance channel angular momentum, determined by analysing the dissipative fragment angular distribution in the framework of the Strutinsky model, is suggested to limit the broadening of the preequilibrium GDR width. (orig.)

  2. Friction conditions in the bearing area of an aluminium extrusion process

    NARCIS (Netherlands)

    Ma, X.; de Rooij, Matthias B.; Schipper, Dirk J.

    2012-01-01

    In aluminium extrusion processes, friction inside the bearing channel is important for controlling the surface quality of the extrusion products. The contact materials show a large hardness difference, one being hot aluminium, and the other being hardened tool steel. Further, the contact pressure is

  3. The limit of grain refinement on equal channel angular deformation

    International Nuclear Information System (INIS)

    Kopylov, V.I.; Chuvil'deev, V.N.

    2004-01-01

    Experimental and theoretical study results on the process of strain-induced grain refinement under severe plastic deformation are described. A generalization is made for experimental results on deformation dispersing of copper, magnesium and aluminium base alloys as well as unalloyed metals. The model is developed which allows calculating the minimal grain size being able to result from equal channel angular pressing. The expressions describing the dependence of the limit of grain refinement on the nature of the material and severe plastic deformation rate and temperature are obtained [ru

  4. Microstructural characteristics of pure gold processed by equal-channel angular pressing

    International Nuclear Information System (INIS)

    Gubicza, J.; Chinh, N.Q.; Szommer, P.; Vinogradov, A.; Langdon, T.G.

    2007-01-01

    Experiments were conducted to evaluate the microstructural characteristics of pure (4N) gold processed by equal-channel angular pressing using routes A or B c . Using atomic force microscopy and X-ray diffraction, it is shown that, although these two routes lead to similar dislocation densities of ∼1.5-1.7 x 10 15 m -2 and similar average grain sizes of ∼460-490 nm, there are significant differences in the shearing patterns and in the densities of planar faults

  5. Effect of equal-channel angular pressing on the creep resistance of precipitation-strengthened alloys

    Czech Academy of Sciences Publication Activity Database

    Sklenička, Václav; Král, Petr; Dvořák, Jiří; Kvapilová, Marie; Kawasaki, M.; Langdon, T. G.

    667-669, - (2011), s. 897-902 ISSN 0255-5476. [NanoSPD5 - International Conference on Nanomaterials by Severe Plastic Deformation /5./. Nanjing, 21.03.2011-25.03.2011] Institutional research plan: CEZ:AV0Z20410507 Keywords : creep * equal-channel angular pressing * precipitation- strength ened alloys * creep damage Subject RIV: JG - Metallurgy

  6. Microstructure quantification of ultrafine grained pure copper fabricated by simple shear extrusion (SSE) technique

    International Nuclear Information System (INIS)

    Bagherpour, E.; Qods, F.; Ebrahimi, R.; Miyamoto, H.

    2016-01-01

    In the present paper commercially pure copper was processed by simple shear extrusion (SSE) technique up to 12 passes using the so-called route C. For SSE processing an appropriate die with a linear die profile was designed and constructed. Effect of SSE passes on isotropy and uniformity of microstructures are focused. Electron back-scattering diffraction (EBSD) was used to evaluate the microstructure of the deformed samples in three orthogonal planes. To investigate the microstructural uniformity EBSD maps were taken from center to periphery of the extrusion direction plane (ED-plane) samples. Significant evolution in grain refinement was achieved down to sub-micron grain size in all planes. Hardness measurements show a considerable increase in hardness of the material after the processing, which confirms the microstructural evolutions. EBSD scans revealed a homogeneous ultrafine grained microstructure after 12 passes. Micro-shear bands were found as potential sites for accelerating the formation of new grains by fragmentation of the initial grains. The total frequency of coincidence site lattice (CSL) boundaries including Σ3 boundaries increased by the increasing of SSE passes. The higher fraction of low to high angle grain boundaries of SSE compared to equal channel angular pressing is an evidence for the cyclic behavior of SSE technique.

  7. Microstructure quantification of ultrafine grained pure copper fabricated by simple shear extrusion (SSE) technique

    Energy Technology Data Exchange (ETDEWEB)

    Bagherpour, E., E-mail: e.bagherpour@semnan.ac.ir [Faculty of Metallurgical and Materials Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Department of Mechanical Engineering, Doshisha University, Kyotanabe, Kyoto 610-0394 (Japan); Qods, F., E-mail: qods@semnan.ac.ir [Faculty of Metallurgical and Materials Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Ebrahimi, R., E-mail: ebrahimy@shirazu.ac.ir [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Miyamoto, H., E-mail: hmiyamot@mail.doshisha.ac.jp [Department of Mechanical Engineering, Doshisha University, Kyotanabe, Kyoto 610-0394 (Japan)

    2016-09-30

    In the present paper commercially pure copper was processed by simple shear extrusion (SSE) technique up to 12 passes using the so-called route C. For SSE processing an appropriate die with a linear die profile was designed and constructed. Effect of SSE passes on isotropy and uniformity of microstructures are focused. Electron back-scattering diffraction (EBSD) was used to evaluate the microstructure of the deformed samples in three orthogonal planes. To investigate the microstructural uniformity EBSD maps were taken from center to periphery of the extrusion direction plane (ED-plane) samples. Significant evolution in grain refinement was achieved down to sub-micron grain size in all planes. Hardness measurements show a considerable increase in hardness of the material after the processing, which confirms the microstructural evolutions. EBSD scans revealed a homogeneous ultrafine grained microstructure after 12 passes. Micro-shear bands were found as potential sites for accelerating the formation of new grains by fragmentation of the initial grains. The total frequency of coincidence site lattice (CSL) boundaries including Σ3 boundaries increased by the increasing of SSE passes. The higher fraction of low to high angle grain boundaries of SSE compared to equal channel angular pressing is an evidence for the cyclic behavior of SSE technique.

  8. Fatigue property and fatigue cracks of ultra-fine grained copper processed by equal-channel angular pressing

    Czech Academy of Sciences Publication Activity Database

    Wang, Q.; Du, Z.; Liu, X.; Kunz, Ludvík

    2011-01-01

    Roč. 2011, č. 682 (2011), s. 231-237 ISSN 1013-9826 Institutional research plan: CEZ:AV0Z20410507 Keywords : ultrafine-grained copper * equal channel angular pressing * fatigue * fatigue cracks Subject RIV: JL - Materials Fatigue, Friction Mechanics

  9. Mechanical Properties of Copper Processed by Equal Channel Angular Pressing

    Science.gov (United States)

    Sülleiová, K.; Ballóková, B.; Besterci, M.; Kvačkaj, T.

    2017-12-01

    The development of the nanostructure in commercial pure copper and the strength and ductility after severe plastic deformation (SPD) with the technology of equal channel angular pressing (ECAP) are analysed. Experimental results and analyses showed that both strength and ductility can be increased simultaneously by SPD. The final grain size decreased from the initial 50μm by SPD to 100-300 nm after 10 passes. An increase of the ductility together with an increase of strength caused by SPD are explained by a strong grain refinement and by a dynamic equilibrium of weakening and strengthening, and it is visible on the final static tensile test stress-strain charts.

  10. Microstructural evolution and mechanical properties of high purity aluminium processed by equal-channel angular pressing

    Czech Academy of Sciences Publication Activity Database

    Dvořák, Jiří; Sklenička, Václav; Horita, Z.

    2008-01-01

    Roč. 49, č. 1 (2008), s. 15-19 ISSN 1345-9678 Institutional research plan: CEZ:AV0Z20410507 Keywords : pure aluminium * equal-channel angular pressing (ECAP) * tensile property * strain rates * grain refinement * stacking fault energy Subject RIV: JJ - Other Materials Impact factor: 0.753, year: 2008

  11. INFLUENCE OF DIE ANGLES ON THE MICROHARDNESS OF ALUMINUM ALLOY PROCESSED BY EQUAL CHANNEL ANGULAR PRESSING

    Directory of Open Access Journals (Sweden)

    Ali A Aljubouri

    2010-11-01

    Full Text Available   The die geometry has a massive effect on the plastic deformation behavior during pressing of material processed by equal channel angular pressing (ECAP method; subsequently the properties of the processed material are strongly dependent on it. Two categories of designed and manufactured dies are used for equal channel angular pressing, a 1200 sharp angle and a 900 round –cornered (200 dies, that produce strain per pass through both dies of ~0.7 and ~1.05   respectively. The microhardness developed in Al-Si alloy during ECAP using route BC. The microhardness increased by a factor of >1.5, after only 1 pressing. Subsequently, the hardness increases slightly up to 8 pressings through the 1200 sharp angle die, while it is increased by a factor of ~2.6 after 5 passes by using the 900 round cornered die, comparing with that for the cast workpiece.

  12. Ultrafine grained steels processed by equal channel angular pressing

    International Nuclear Information System (INIS)

    Shin, Dong Hyuk; Park, Kyung-Tae

    2005-01-01

    Recent development of ultrafine grained (UFG) low carbon steels by using equal channel angular pressing (ECAP) and their room temperature tensile properties are reviewed, focusing on the strategies overcoming their inherent mechanical drawbacks. In addition to ferrite grain refinement, when proper post heat treatments are imposed, carbon atom dissolution from pearlitic cementite during ECAP can be utilized for microstructural modification such as uniform distribution of nano-sized cementite particles or microalloying element carbides inside UFG ferrite grains and fabrication of UFG ferrite/martensite dual phase steel. The utilization of nano-sized particles is effective on improving thermal stability of UFG low carbon ferrite/pearlite steel but less effective on improving its tensile properties. By contrast, UFG ferrite/martensite dual phase steel exhibits an excellent combination of ultrahigh strength, large uniform elongation and extensive strain hardenability

  13. Comparison of the monotonic and cyclic mechanical properties of ultrafine-grained low carbon steels processed by continuous and conventional equal channel angular pressing

    International Nuclear Information System (INIS)

    Niendorf, T.; Böhner, A.; Höppel, H.W.; Göken, M.; Valiev, R.Z.; Maier, H.J.

    2013-01-01

    Highlights: ► UFG low-carbon steel was successfully processed by continuous ECAP-Conform. ► Continuously processed UFG steel shows high performance. ► High monotonic strength and good ductility. ► Microstructural stability under cyclic loading in the LCF regime. ► Established concepts can be used for predicting the properties. - Abstract: In the current study the mechanical properties of ultra-fine grained low carbon steel processed by conventional equal channel angular pressing and a continuous equal channel angular pressing-Conform process were investigated. Both monotonic and cyclic properties were determined for the steel in either condition and found to be very similar. Microstructural analyses employing electron backscatter diffraction were used for comparison of the low carbon steels processed by either technique. Both steels feature very similar grain sizes and misorientation angle distributions. With respect to fatigue life the low carbon steel investigated shows properties similar to ultra-fine grained interstitial-free steel processed by conventional equal channel angular pressing, and thus, the general fatigue behavior can be addressed following the same routines as proposed for interstitial-free steel. In conclusion, the continuously processed material exhibits very promising properties, and thus, equal channel angular pressing-Conform is a promising tool for production of ultra-fine grained steels in a large quantity

  14. Fatigue strength of a magnesium MA2-1 alloy after equal-channel angular pressing

    Science.gov (United States)

    Terent'ev, V. F.; Dobatkin, S. V.; Prosvirnin, D. V.; Bannykh, I. O.; Kopylov, V. I.; Serebryany, V. N.

    2010-09-01

    The fatigue strength of a magnesium MA2-1 alloy is studied after annealing and equal-channel angular pressing (ECAP). The ultrafine-grained structure formed upon ECAP is shown to increase the plasticity of the material during static tension, to decrease the cyclic life to failure, and not to decrease the fatigue limit. The mechanisms of crack nucleation and growth during cyclic deformation are investigated.

  15. Obtención de microestructuras de grano ultrafino en aleaciones de aluminio mediante extrusión en canal angular (ECAE

    Directory of Open Access Journals (Sweden)

    Alkorta, J.

    2004-04-01

    Full Text Available Al 5083 samples have been subjected to 90º equal-channel angular extrusion (ECAE at 270ºC. After ECAE, the microhardness was measured and the texture for the plane perpendicular to the extrusion direction was analysed by X-Rays and EBSD. The microstructure was characterized by optical microscopy and EBSD. As deformation accumulates the hardness increases until it reaches saturation at an effective strain of about ε∼4. With regard to the texture, it has been shown that a high density of {111} planes are oriented parallel to the shear plane of the last pass.

    Varias muestras de aluminio 5083 se han sometido a extrusiones en canal angular de 90º a 270ºC. A continuación se midieron las durezas de las muestras obtenidas y se caracterizó la textura en el plano perpendicular a la dirección de extrusión mediante Rayos-X y difracción de electrones retrodispersados (EBSD. La caracterización microestructural se hizo mediante microscopio óptico y EBSD. Se ha observado que la dureza aumenta sensiblemente con el grado de deformación y que alcanza un nivel máximo de saturación a partir de ε∼4. En cuanto a la textura, se observa que los planos {111} tienden a orientarse paralelos al plano de la última cortadura.

  16. Comparisons of microstructures and texture and mechanical properties of magnesium alloy fabricated by compound extrusion and direct extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Hu, H.-J., E-mail: hhj@cqut.edu.cn [Chongqing University of Technology, Chongqing 400050 (China); PLA Chongqing Logistics Engineering College, 401311 (China); Ying, Y.-L. [Chongqing University of Technology, Chongqing 400050 (China); Ou, Z.-W. [PLA Chongqing Logistics Engineering College, 401311 (China); Wang, X.-Q. [The University of Alabama, Tuscaloosa, AL 35487 (United States)

    2017-05-17

    In this study, microstructure evolution, textures and mechanical properties of AZ61 magnesium alloy were investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and tensile tests. The samples were processed by a new compound extrusion (CE) which combines direct extrusion (DE) and two steps of equal channel anger extrusion (ECAE). The results show that CE process can refine the microstructure more effectively than the DE process. The CE-fabricated samples have a weaker texture (0002), and a more fine and homogeneous microstructures, which attributes to the additional two steps of ECAE in CE process. In CE process, twin dynamic recrystallization and rotational dynamic recrystallization occurred, which enhances the refinement of the grains and weakening of the texture. In addition, the samples fabricated by CE process display a higher tensile properties (yield strength, tensile strength and elongation) with an excellent balance of strength and tensile ductility. Based on this study, severe plastic deformation (SPD) techniques combining conventional DE and two steps ECAE into a single process are feasibility to improve the mechanical properties of AZ61 Mg alloy.

  17. Enhancement effect of inter-pass annealing during equal channel angular pressing on grain refinement and ductility of 9Cr1Mo steel

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Ting, E-mail: hao.ting@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Tangi, Haiyin [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Luo, Guangnan [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China); Wang, Xianping; Liu, Changsong [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Fang, Qianfeng, E-mail: qffang@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China)

    2016-06-14

    To obtain enhanced mechanical property in both the strength and the ductility, 9Cr1Mo steel (T91) was severely deformed by equal channel angular pressing (ECAP) combined with an additional inter-pass annealing. Tensile results show that the additional inter-pass annealing can significantly improve the ductility (i.e. 18% of the total elongation after four-pass extrusion with the inter-pass annealing) but slightly decrease the tensile strength comparing with the case without the inter-pass annealing (i.e. 10% of the total elongation after four-pass ECAP processing). The average grain size of the two passes ECAP-processed materials with the inter-pass annealing (~0.8 µm) is smaller than that of the sample without inter-pass annealing (~2 µm), and the fraction of the high angle grain boundaries in the samples with the inter-pass annealing (~40%) is higher than that of ~34% (two-pass ECAP) without the inter-pass annealing based on electron backscattering diffraction analysis. The crystallite size and dislocation density were evaluated by means of the modified Williamson-Hall plot based on X-ray diffraction analysis. The microstructural analysis indicates that the enhanced ductility of the ECAP processed and inter-pass annealed materials can be attributed to the relatively smaller grain sizes, larger crystallite sizes and lower dislocation densities.

  18. Enhancement effect of inter-pass annealing during equal channel angular pressing on grain refinement and ductility of 9Cr1Mo steel

    International Nuclear Information System (INIS)

    Hao, Ting; Tangi, Haiyin; Luo, Guangnan; Wang, Xianping; Liu, Changsong; Fang, Qianfeng

    2016-01-01

    To obtain enhanced mechanical property in both the strength and the ductility, 9Cr1Mo steel (T91) was severely deformed by equal channel angular pressing (ECAP) combined with an additional inter-pass annealing. Tensile results show that the additional inter-pass annealing can significantly improve the ductility (i.e. 18% of the total elongation after four-pass extrusion with the inter-pass annealing) but slightly decrease the tensile strength comparing with the case without the inter-pass annealing (i.e. 10% of the total elongation after four-pass ECAP processing). The average grain size of the two passes ECAP-processed materials with the inter-pass annealing (~0.8 µm) is smaller than that of the sample without inter-pass annealing (~2 µm), and the fraction of the high angle grain boundaries in the samples with the inter-pass annealing (~40%) is higher than that of ~34% (two-pass ECAP) without the inter-pass annealing based on electron backscattering diffraction analysis. The crystallite size and dislocation density were evaluated by means of the modified Williamson-Hall plot based on X-ray diffraction analysis. The microstructural analysis indicates that the enhanced ductility of the ECAP processed and inter-pass annealed materials can be attributed to the relatively smaller grain sizes, larger crystallite sizes and lower dislocation densities.

  19. Simulação computacional, projeto, construção e análise do desempenho de uma matriz para extrusão em canal angular dedicada ao processamento de chapas

    OpenAIRE

    Phillip Springer

    2012-01-01

    O presente trabalho descreve o projeto, construção e testes de uma matriz de Extrusão em Canal Angular (ECA) dedicada ao processamento de amostras em forma de chapa. O parâmetro construtivo fundamental de uma matriz deste tipo é a geometria dos canais, especialmente o ângulo de encontro dos mesmos e os raios de curvatura nesse ponto. O material de trabalho empregado é o Al comercial AA1050. A motivação deste projeto é prover o ferramental necessário para produção de amostras que serão utiliza...

  20. Initial porosity impact on equal channel angular pressing (ECAP of Ti–6Al–4V powder material

    Directory of Open Access Journals (Sweden)

    V. A. Andreyachshenko

    2016-10-01

    Full Text Available There is studied the technology of processing Ti-6Al-4V powder material with various initial densities using the method of equal channel angular pressing. The device with the 90, 120 and 135 degree angled joint channels was used for the study. The deformation was carried out at the room temperature. It was found that the most favorable stressed-and-strained state was formed in the instrument where the angle of channel joints was equal to 135 degrees. The maximum compression in the instrument is reached at 90 degree angle of the channel joints, but it needs a larger deformation force. To obtain pressed material it is recommended to use a high ECAP cycle for any configuration.

  1. Texture in equal-channel angular pressed aluminum and nickel

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, S.C.; Beyerlein, I.J.; Bourke, M.A.M.; Tome, C.N.; Rangaswamy, P. [Los Alamos National Lab., Los Alamos, NM (United States); Xu, C.; Langdon, T.G. [Univ. of Southern California, Los Angeles, CA (United States)

    2002-07-01

    Nano-structured metals with advantageous mechanical properties can be produced using severe plastic deformation techniques such as equal channel angular pressing (ECAP). Metals and alloys processed by ECAP have much higher yield strengths than the equivalent unprocessed material while retaining high ductilities, an extremely attractive combination of properties. Implicit in the process are the introduction of repetitive shear strains of 100% which introduce texture, the modeling of which is challenging. In this work, we present results from a neutron diffraction study on aluminum and nickel samples processed by ECAP. The results are compared to predictions from a visco-plastic self-consistent (VPSC) model. By taking into account grain-grain interactions in the model the agreement between the predicted and measured orientation distributions is improved. The results show also that the initial texture affects the texture evolution, at least up to strains of the order of {proportional_to}1, i.e. one ECAP pass. (orig.)

  2. Effect of extrusion stem speed on extrusion process for a hollow aluminum profile

    International Nuclear Information System (INIS)

    Zhang, Cunsheng; Zhao, Guoqun; Chen, Zhiren; Chen, Hao; Kou, Fujun

    2012-01-01

    Highlights: ► Extrusion stem speed has significant effects on extrusion process. ► An optimum value of stem speed exists for uniform metal flow distribution. ► A higher stem speed leads to a higher required extrusion force. ► A high stem speed leads to an improved welding quality of aluminum profile. - Abstract: Extrusion stem speed is one of important process parameters during aluminum profile extrusion, which directly influences the profile quality and choice of extrusion equipments. In this paper, the extrusion process of a thin-walled hollow aluminum profile was simulated by means of the HyperXtrude commercial software. Through a serial of numerical simulation, the effects of stem speed on extrusion process, such as metal flow behavior at die exit, temperature distribution, extrusion force, and welding pressure, have been investigated. The numerical results showed that there existed an optimum value of stem speed for flow velocity distribution. With the increasing stem speed, the temperature of the extrudate and required extrusion force increased, and the welding quality of extrudate would be improved. Through comprehensive comparison and analysis, the appropriate stem speed could be determined for practical extrusion production. Thus, the research results could give effective guideline for determining initial billet and die temperature and choosing the proper extrusion press in aluminum profile industry.

  3. Siegert pseudostate formulation of scattering theory: Nonzero angular momenta in the one-channel case

    International Nuclear Information System (INIS)

    Batishchev, Pavel A.; Tolstikhin, Oleg I.

    2007-01-01

    The Siegert pseudostate (SPS) formulation of scattering theory, originally developed by Tolstikhin, Ostrovsky, and Nakamura [Phys. Rev. A, 58, 2077 (1998)] for s-wave scattering in a spherically symmetric finite-range potential, is generalized to nonzero angular momenta. The orthogonality and completeness properties of SPSs are established and SPS expansions for the outgoing-wave Green's function, physical states, and scattering matrix are obtained. The present formulation completes the theory of SPSs in the one-channel case, making its application to three-dimensional problems possible. The results are illustrated by calculations for several model potentials

  4. High Temperature Deformation of Twin-Roll Cast Al-Mn-Based Alloys after Equal Channel Angular Pressing.

    Science.gov (United States)

    Málek, Přemysl; Šlapáková Poková, Michaela; Cieslar, Miroslav

    2015-11-12

    Twin roll cast Al-Mn- and Al-Mn-Zr-based alloys were subjected to four passes of equal channel angular pressing. The resulting grain size of 400 nm contributes to a significant strengthening at room temperature. This microstructure is not fully stable at elevated temperatures and recrystallization and vast grain growth occur at temperatures between 350 and 450 °C. The onset of these microstructure changes depends on chemical and phase composition. Better stability is observed in the Al-Mn-Zr-based alloy. High temperature tensile tests reveal that equal channel angular pressing results in a softening of all studied materials at high temperatures. This can be explained by an active role of grain boundaries in the deformation process. The maximum values of ductility and strain rate sensitivity parameter m found in the Al-Mn-Zr-based alloy are below the bottom limit of superplasticity (155%, m = 0.25). However, some features typical for superplastic behavior were observed-the strain rate dependence of the parameter m , the strengthening with increasing grain size, and the fracture by diffuse necking. Grain boundary sliding is believed to contribute partially to the overall strain in specimens where the grain size remained in the microcrystalline range.

  5. Orbital angular momentum in four channel spatial domain multiplexing system for multi-terabit per second communication architectures

    Science.gov (United States)

    Murshid, Syed H.; Muralikrishnan, Hari P.; Kozaitis, Samuel P.

    2012-06-01

    Bandwidth increase has always been an important area of research in communications. A novel multiplexing technique known as Spatial Domain Multiplexing (SDM) has been developed at the Optronics Laboratory of Florida Institute of Technology to increase the bandwidth to T-bits/s range. In this technique, space inside the fiber is used effectively to transmit up to four channels of same wavelength at the same time. Experimental and theoretical analysis shows that these channels follow independent helical paths inside the fiber without interfering with each other. Multiple pigtail laser sources of exactly the same wavelength are used to launch light into a single carrier fiber in a fashion that resulting channels follow independent helical trajectories. These helically propagating light beams form optical vortices inside the fiber and carry their own Orbital Angular Momentum (OAM). The outputs of these beams appear as concentric donut shaped rings when projected on a screen. This endeavor presents the experimental outputs and simulated results for a four channel spatially multiplexed system effectively increasing the system bandwidth by a factor of four.

  6. The Prediction of Microstructure Evolution of 6005A Aluminum Alloy in a P-ECAP Extrusion Study

    Science.gov (United States)

    Lei, Shi; Jiu-Ba, Wen; Chang, Ren

    2018-04-01

    Finite element modeling (FEM) was applied for predicting the recrystallized structure in extruded 6005 aluminum alloy, and simulated results were experimentally validated. First, microstructure evolution of 6005 aluminum alloy during deformation was studied by means of isothermal compression test, where the processing parameters were chosen to reproduce the typical industrial conditions. Second, microstructure evolution was analyzed, and the obtained information was used to fit a dynamic recrystallization model implementing inside the DEFORM-3D FEM code environment. FEM of deformation of 6005 aluminum has been established and validated by microstructure comparison. Finally, the obtained dynamic recrystallization model was applied to tube extrusion by using a portholes-equal channel angular pressing die. The finite element analysis results showed that coarse DRX grains occur in the extruded tube at higher temperature and in the extruded tube at the faster speed of the stem. The test results showed material from the front end of the extruded tube has coarse grains (60 μm) and other extruded tube has finer grains (20 μm).

  7. The Prediction of Microstructure Evolution of 6005A Aluminum Alloy in a P-ECAP Extrusion Study

    Science.gov (United States)

    Lei, Shi; Jiu-Ba, Wen; Chang, Ren

    2018-05-01

    Finite element modeling (FEM) was applied for predicting the recrystallized structure in extruded 6005 aluminum alloy, and simulated results were experimentally validated. First, microstructure evolution of 6005 aluminum alloy during deformation was studied by means of isothermal compression test, where the processing parameters were chosen to reproduce the typical industrial conditions. Second, microstructure evolution was analyzed, and the obtained information was used to fit a dynamic recrystallization model implementing inside the DEFORM-3D FEM code environment. FEM of deformation of 6005 aluminum has been established and validated by microstructure comparison. Finally, the obtained dynamic recrystallization model was applied to tube extrusion by using a portholes-equal channel angular pressing die. The finite element analysis results showed that coarse DRX grains occur in the extruded tube at higher temperature and in the extruded tube at the faster speed of the stem. The test results showed material from the front end of the extruded tube has coarse grains (60 μm) and other extruded tube has finer grains (20 μm).

  8. Network of Porosity Formed in Ultrafine-Grained Copper Produced by Equal Channel Angular Pressing

    Science.gov (United States)

    Ribbe, Jens; Baither, Dietmar; Schmitz, Guido; Divinski, Sergiy V.

    2009-04-01

    Radiotracer experiments on diffusion of Ni63 and Rb86 in severely deformed commercially pure copper (8 passes of equal channel angular pressing) reveal unambiguously the existence of ultrafast transport paths. A fraction of these paths remains in the material even after complete recrystallization. Scanning electron microscopy and focused ion beam techniques are applied. Deep grooves are found which are related to original high-energy interfaces. In-depth sectioning near corresponding triple junctions reveals clearly multiple microvoids or microcracks caused by the severe deformation. Long-range tracer penetration over tens of micrometers proves that these submicrometer-large defects are connected by highly diffusive paths and that they appear with significant frequency.

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

    Directory of Open Access Journals (Sweden)

    R. B. Mei

    2015-01-01

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

  10. Multi-channel Spiral Twist Extrusion (MCSTE): A Novel Severe Plastic Deformation Technique for Grain Refinement

    Science.gov (United States)

    El-Garaihy, W. H.; Fouad, D. M.; Salem, H. G.

    2018-04-01

    Multi-channel Spiral Twist Extrusion (MCSTE) is introduced as a novel severe plastic deformation (SPD) technique for producing superior mechanical properties associated with ultrafine grained structure in bulk metals and alloys. The MCSTE design is based on inserting a uniform square cross-sectioned billet within stacked disks that guarantee shear strain accumulation. In an attempt to validate the technique and evaluate its plastic deformation characteristics, a series of experiments were conducted. The influence of the number of MCSTE passes on the mechanical properties and microstructural evolution of AA1100 alloy were investigated. Four passes of MCSTE, at a relatively low twisting angle of 30 deg, resulted in increasing the strength and hardness coupled with retention of ductility. Metallographic observations indicated a significant grain size reduction of 72 pct after 4 passes of MCSTE compared with the as-received (AR) condition. Moreover, the structural uniformity increased with the number of passes, which was reflected in the hardness distribution from the peripheries to the center of the extrudates. The current study showed that the MCSTE technique could be an effective, adaptable SPD die design with a promising potential for industrial applications compared to its counterparts.

  11. Metal extrusion using hydrostatic pressures

    International Nuclear Information System (INIS)

    Sauve, Ch.

    1965-01-01

    The main problems connected with the deformation of metals due to extrusion are described. A method is put forward for calculating the rational rate of percentage deformation in the case of bar extrusion using a cylindrical container; reference is made to previous work on extrusion using a hydrostatic pressure with or without back-pressure. An extrusion process is described using hydrostatic pressure, without back-pressure, and using the lubricant for transmitting the thrust. This process has been used for eight years by the C.E.A. for the extrusion of a very wide range of metals, from beryllium to uranium and including steels; it leads to excellent surface textures. A very fine crystallization can be obtained on extruded products when the rate of extrusion is very low. There appears to be nothing against the use of high extrusion rates using this method. (author) [fr

  12. Consolidation of Fe-N Magnets Using Equal Channel Angular Extrusion

    Science.gov (United States)

    2016-03-23

    rare-earth crisis ”, it is better and more scientifically sound in the long term to pursue this type of research and development. For instance...α’). Proc Roy Soc. 1951;A208:200. 2. Kim TK, Takahashi M. New magnetic material having ultrahigh magnetic- moment. Appl Phys Lett. 1972;20:492. 3...single-crystal films. J Appl Phys. 1991;70:5977. 4. Wallace WE, Huang MQ. Enhanced Fe moment in nitrogen martensite and Fe16N2. J Appl Phys. 1994;76

  13. Microstructural evolution in a spray-cast aluminum alloy during equal-channel angular pressing

    International Nuclear Information System (INIS)

    Gao Nong; Starink, Marco J.; Furukawa, Minoru; Horita, Zenji; Xu Cheng; Langdon, Terence G.

    2005-01-01

    A spray-cast Al-7034 alloy was processed by equal-channel angular pressing (ECAP) to a total of eight passes at 473 K and the pressed samples were examined using transmission electron microscopy, differential scanning calorimetry and electron back-scatter diffraction. It is shown that the grain size of the alloy is reduced to ∼0.3 μm by ECAP and the high pressures associated with ECAP lead to a fragmentation of the rod-like η-phase. The high temperature of ECAP also produces a precipitation of η-phase. There is an increase in the fraction of high-angle boundaries during the initial passes of ECAP but the fraction of low-angle boundaries remains high even after eight passes

  14. Influence of equal-channel angular pressing on precipitation in an Al-Zn-Mg-Cu alloy

    International Nuclear Information System (INIS)

    Sha, G.; Wang, Y.B.; Liao, X.Z.; Duan, Z.C.; Ringer, S.P.; Langdon, T.G.

    2009-01-01

    Processing by equal-channel angular pressing (ECAP) affects the morphology of η precipitates in an Al-Zn-Mg-Cu (Al-7136) alloy. It is shown by transmission electron microscopy that ECAP changes the orientation of precipitates and this influences the atomic configuration and the interfacial energy at the η/α-Al interfaces. Consequently, η precipitates adopt an isotropic growth mode and evolve into equiaxed particles. A three-dimensional atom probe analysis demonstrates that large η precipitates formed in different numbers of ECAP passes are of similar composition. The coalescence of smaller precipitates, rather than the fragmentation of larger precipitates, dominates the precipitate evolution.

  15. Amplitude damping channel for orbital angular momentum

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2010-03-01

    Full Text Available Since the pioneering work on the entanglement of the orbital angular momentum (OAM) states of light, much attention has been devoted to the subject, with particular attention into the quantum aspects of information processing using OAM. Furthermore...

  16. Effect of friction stirring on microstructure in equal channel angular pressed aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Y.S.; Urata, M.; Kokawa, H.; Ikeda, K. [Dept. of Materials Processing, Graduate School of Engineering, Tohoku Univ., Aoba-yama, Sendai (Japan)

    2003-07-01

    Friction stir welding (FSW) was applied to equal channel angular (ECA) pressed aluminum (Al) alloys with high strength and toughness, and the effect of FSW on microstructure and the hardness profile in ECA-pressed alloys was examined. In the weld of ECA-pressed Al alloy 1050 and 5083, the stir zone had roughly the same hardness as the ECA-pressed material, while the hardness was slightly reduced in the thermo-mechanically affected zone (TMAZ). The reduction of hardness in the TMAZ was due to dynamic recovery of dislocation cells of the ECA-pressed material. The addition of Zr to Al suppressed the reduction of hardness in the TMAZ. Consequently, friction stir (FS) weld of Al-Zr alloy retained the hardness of the ECA-pressed material throughout the weld. (orig.)

  17. Etching Behavior of Aluminum Alloy Extrusions

    Science.gov (United States)

    Zhu, Hanliang

    2014-11-01

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

  18. Effect of Equal-Channel Angular Pressing on Pitting Corrosion of Pure Aluminum

    Directory of Open Access Journals (Sweden)

    Injoon Son

    2012-01-01

    Full Text Available The effect of equal-channel angular pressing (ECAP on the pitting corrosion of pure Al was investigated using electrochemical techniques in solutions containing 0.1 m mol·dm−3 of Na2SO4 and 8.46 mol·dm−3 of NaCl (300 ppm Cl− and followed by surface analysis. The potential for pitting corrosion of pure Al was clearly shifted in the noble direction by the ECAP process indicating that this process improves resistance to pitting corrosion. The time dependence of corrosion potential and the anodic potential at 1 A·m−2 revealed that the rate of formation of Al oxide films increased due to a decrease in the grain size of the Al after ECAP. Since there exists a negligible amount of impurity precipitates in pure Al, the improvement in pitting corrosion resistance of pure Al by ECAP appears to be attributable to an increase in the rate of formation of Al oxide films.

  19. Characterization of nanostructured pure aluminum tubes produced by tubular channel angular pressing (TCAP)

    Energy Technology Data Exchange (ETDEWEB)

    Mesbah, M. [Centre of Advanced Manufacturing and Material Processing, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Faraji, G., E-mail: ghfaraji@ut.ac.ir [School of Mechanical Engineering, College of Engineering, University of Tehran, 11155-4563 Tehran (Iran, Islamic Republic of); Centre of Advanced Manufacturing and Material Processing, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Bushroa, A.R. [Centre of Advanced Manufacturing and Material Processing, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-01-10

    Ultrafine grained (UFG) aluminum tubes were fabricated by the tubular channel angular pressing (TCAP) process. The microstructural evolution was characterized by transmission electron microscopy (TEM) and mechanical properties were evaluated by compression test and hardness measurements. TEM analysis of specimen subjected to one TCAP pass showed the formation of an array of elongated subgrains with high angle grain boundaries. Increase in the number of passes changes the elongated grains to equiaxed grains with ∼310 nm sizes. Microhardness value of the processed tubes was enhanced to 49.4 Hv after one pass from an initial value of 32.9 Hv. Yield and ultimate strengths were increased 2.5 and 2.28 times as compared to annealed specimen. Compression tests also showed that UFG aluminum tubes exhibit lower work hardening and almost perfect plastic behavior without any failure.

  20. Characterization of nanostructured pure aluminum tubes produced by tubular channel angular pressing (TCAP)

    International Nuclear Information System (INIS)

    Mesbah, M.; Faraji, G.; Bushroa, A.R.

    2014-01-01

    Ultrafine grained (UFG) aluminum tubes were fabricated by the tubular channel angular pressing (TCAP) process. The microstructural evolution was characterized by transmission electron microscopy (TEM) and mechanical properties were evaluated by compression test and hardness measurements. TEM analysis of specimen subjected to one TCAP pass showed the formation of an array of elongated subgrains with high angle grain boundaries. Increase in the number of passes changes the elongated grains to equiaxed grains with ∼310 nm sizes. Microhardness value of the processed tubes was enhanced to 49.4 Hv after one pass from an initial value of 32.9 Hv. Yield and ultimate strengths were increased 2.5 and 2.28 times as compared to annealed specimen. Compression tests also showed that UFG aluminum tubes exhibit lower work hardening and almost perfect plastic behavior without any failure

  1. SPOT WELDING COPPER–1%Cr ELECTRODE TIPS PRODUCED VIA EQUAL CHANNEL ANGULAR PRESSING

    Directory of Open Access Journals (Sweden)

    Luay Bakir Hussain

    2010-09-01

    Full Text Available A sharp 120o Equal channel angular pressing (ECAP following rout Bc was applied at room temperature to refine the grains sizes of pure copper and copper-1%Chromium alloy for spot welding electrode tips application. Initially deformation behavior was investigated with the position using colorful plasticine as work piece followed by copper alloy. It was found the deformation at the central part of the work piece is heavily sheared than the outer part. Optical and Scanning electron microscopy were used to study the progress of grain refining under the influence of rotation and number of passes during pressing. The influnece of elongated fibrous nano graines on electrical conductivity and hardness were discussed. Shear test of spot welded 303 stainless steel indicated that nano structural Cu-1%Cr electrode tips used showed a superior results compared to commercial electrodes

  2. 2 Tbit/s free-space data transmission on two orthogonal orbital-angular-momentum beams each carrying 25 WDM channels.

    Science.gov (United States)

    Fazal, Irfan M; Ahmed, Nisar; Wang, Jian; Yang, Jeng-Yuan; Yan, Yan; Shamee, Bishara; Huang, Hao; Yue, Yang; Dolinar, Sam; Tur, Moshe; Willner, Alan E

    2012-11-15

    We demonstrate a 2 Tbit/s free-space data link using two orthogonal orbital angular momentum beams each carrying 25 different wavelength-division-multiplexing channels. We measure the performance for different modulation formats, including directly detected 40 Gbit/s nonreturn-to-zero (NRZ) differential phase-shift keying, 40 Gbit/s NRZ on-off keying, and coherently-detected 10 Gbaud NRZ quadrature phase-shift keying, and achieve low bit error rates with penalties less than 5 dB.

  3. Microstructure strengthening mechanisms in an Al–Mg–Si–Sc–Zr equal channel angular pressed aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Cabibbo, Marcello, E-mail: m.cabibbo@univpm.it [Dipartimento di Ingegneria Meccanica e Scienze Matematiche (DIISM), Università Politecnica delle Marche, 60131 Ancona (Italy)

    2013-09-15

    Microstructure dislocation strengthening mechanisms in severely deformed aluminium strongly depend on the different boundary evolutions. Thereafter, models of proof stress determination should take into account the different nature of the boundaries that form during severe plastic deformation. In the last few decades, Hall–Petch modified relationship and other proof stress modelling were extensively discussed. This paper deals with further insights into the Hansen's and other authors approach to the modelling of aluminium poof stress after equal channel angular pressing. The present model is based on a detailed transmission electron microscopy microstructure characterization of the different strengthening contributions in an age-hardened Al–Mg–Si–Sc–Zr alloy.

  4. Microstructure strengthening mechanisms in an Al–Mg–Si–Sc–Zr equal channel angular pressed aluminium alloy

    International Nuclear Information System (INIS)

    Cabibbo, Marcello

    2013-01-01

    Microstructure dislocation strengthening mechanisms in severely deformed aluminium strongly depend on the different boundary evolutions. Thereafter, models of proof stress determination should take into account the different nature of the boundaries that form during severe plastic deformation. In the last few decades, Hall–Petch modified relationship and other proof stress modelling were extensively discussed. This paper deals with further insights into the Hansen's and other authors approach to the modelling of aluminium poof stress after equal channel angular pressing. The present model is based on a detailed transmission electron microscopy microstructure characterization of the different strengthening contributions in an age-hardened Al–Mg–Si–Sc–Zr alloy.

  5. Microstructural and mechanical characteristics of EUROFER'97 processed by equal channel angular pressing

    International Nuclear Information System (INIS)

    Fernandez, P.; Eddahbi, M.; Auger, M.A.; Leguey, T.; Monge, M.A.; Pareja, R.

    2011-01-01

    EUROFER'97 was processed by equal channel angular pressing (ECAP) at 823 K for a total of 4 or 8 passes, using a die angle of 105 o , and its microstructure and tensile behavior in temperature range 568-873 K investigated. A single ECAP pass developed a deformation texture {1 1 0} that was practically stable during subsequent ECAP passes. The materials processed by 1 or 2 passes exhibited a fine microstructure of recovered subgrains and tensile behavior very similar to that for the tempered material in the as-received condition. The materials processed using 4 or 8 passes exhibited nearly equiaxial submicron grained structures with a high density of high-angle grain boundaries. These materials became softer than the as-received material at a testing temperature of ∼823 K. EUROFER ECAP processed under the present conditions exhibited hardening ratio somewhat higher than that of the as-received material.

  6. The reactive extrusion of thermoplastic polyurethane

    NARCIS (Netherlands)

    Verhoeven, Vincent Wilhelmus Andreas

    2006-01-01

    The objective of this thesis was to increase the understanding of the reactive extrusion of thermoplastic polyurethane. Overall, several issues were identified: • Using a relative simple extrusion model, the reactive extrusion process can be described. This model can be used to further investigate

  7. Microstructure and anisotropy of the mechanical properties in commercially pure titanium after equal channel angular pressing with back pressure at room temperature

    Czech Academy of Sciences Publication Activity Database

    Jäger, Aleš; Gärtnerová, Viera; Tesař, Karel

    2015-01-01

    Roč. 644, Sep (2015), s. 114-120 ISSN 0921-5093 R&D Projects: GA ČR GBP108/12/G043 Institutional support: RVO:68378271 Keywords : equal channel angular processing * nanostructured materials * phase transformation * grain refinement * mechanical anisotropy * high pressure omega phase Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.647, year: 2015

  8. Angular dispersion and energy loss of H+ and He+ in metals

    International Nuclear Information System (INIS)

    Cantero, Esteban

    2006-01-01

    In this master thesis the effects produced when a light ion beam traverses a thin metallic film were studied.In particular, the interactions of low energy (E ≤ 10 keV) light ions (H + ,H 2 + , D + , He + ) with monocrystalline and also polycrystalline gold samples were investigated.In first place, the dependence of the stopping power with projectiles' velocity was studied, analyzing the threshold effect in the excitation of the 5d electrons in the channelling regime for energies between 0,4 and 9 keV.Next, the angular dispersion of ions in polycrystalline and monocrystalline films was measured and analyzed.Comparisons for different energies and projectiles were done, studying molecular and isotopic effects.Using Lindhard's channeling theory, a scale law for the angular dispersion of angles greater than the critical angle was found.Additionally, the angular dependence of the energy loss and the energy loss straggling of protons transmitted through monocrystals were measured.To explain the angular variations of these magnitudes a theoretical model based on the electronic density fluctuations inside the channel was developed [es

  9. Numerical Simulation and Experimental Analysis of The Equal Channel Angular Pressing of Pure Titanium

    Energy Technology Data Exchange (ETDEWEB)

    Quang, Pham; Nghiep, Do Minh [Hanoi University of Science and Technology, Hanoi (Viet Nam)

    2016-03-15

    The plastic deformation behavior of pure Ti during equal channel angular pressing (ECAP) is simulated using the three-dimension finite volume method and is experimentally investigated. The calculated effective strain and effective stress distributions and histories are analyzed to understand the local and global deformation characteristics. The predicted plastic deformation behavior of the Ti workpiece during the ECAP process was compared with the theoretical total strain for every pass at RAM speed v of 10 mm/s and at constant temperature of 400 ℃. The simulated strain and stress distributions are homogenous in the central region of the ECAP processed Ti. The experimental ECAP performed with four, eight, and twelve passes at 400 ℃ results in refined grain sizes of approximately 5-10 µm, 0.4⁓0.5 µm and 0.1⁓0.2 µm, respectively.

  10. EBSD Analysis of Deformed and Partially Recrystallized Microstructures in ECAE-Processed Copper

    DEFF Research Database (Denmark)

    Mishin, Oleg; Bowen, Jacob R.; Godfrey, A.

    2012-01-01

    The deformed microstructure and recrystallization behavior of copper samples processed using equal channel angular extrusion (ECAE) have been investigated. The heavily deformed microstructure was found to be non-uniform through the sample thickness and to vary in a manner consistent with the non...

  11. Inline monitoring and a PAT strategy for pharmaceutical hot melt extrusion.

    Science.gov (United States)

    Wahl, Patrick R; Treffer, Daniel; Mohr, Stefan; Roblegg, Eva; Koscher, Gerold; Khinast, Johannes G

    2013-10-15

    Implementation of continuous manufacturing in the pharmaceutical industry requires tight process control. This study focuses on a PAT strategy for hot melt extrusion of vegetable calcium stearate (CaSt) as matrix carrier and paracetamol as active pharmaceutical ingredient (API). The extrusion was monitored using in-line near-infrared (NIR) spectroscopy. A NIR probe was located in the section between the extrusion screws and the die, using a novel design of the die channel. A chemometric model was developed based on premixes at defined concentrations and was implemented in SIPAT for real time API concentration monitoring. Subsequently, step experiments were performed for different API concentrations, screw speeds and screw designs. The predicted API concentration was in good agreement with the pre-set concentrations. The transition from one API plateau to another was a smooth curve due to the mixing behaviour of the extruder. The accuracy of the model was confirmed via offline HPLC analysis. The screw design was determined as the main influential factor on content uniformity (CU). Additionally the influence of multiple feeders had a significant impact on CU. The results demonstrate that in-line NIR measurements is a powerful tool for process development (e.g., mixing characterization), monitoring and further control strategies. Copyright © 2013. Published by Elsevier B.V.

  12. Estimation of the mechanical properties of aluminium and an aluminium composite after equal channel angular pressing by means of the small punch test

    Czech Academy of Sciences Publication Activity Database

    Dobeš, Ferdinand; Dymáček, Petr; Besterci, M.

    2015-01-01

    Roč. 626, FEB (2015), s. 313-321 ISSN 0921-5093 R&D Projects: GA ČR(CZ) GAP108/12/1452; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Mechanical characterization * Aluminium alloys * Composites * Equal channel angular processing * Grain refinement Subject RIV: JI - Composite Materials Impact factor: 2.647, year: 2015

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

    Science.gov (United States)

    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.

  14. Solid-State Recycling of Light Metal Reinforced Inclusions by Equal Channel Angular Pressing: A Review

    Directory of Open Access Journals (Sweden)

    Al-Alimi Sami.

    2017-01-01

    Full Text Available Solid-state recycling of light metals reinforced inclusions through hot Equal Channel Angular Pressing (ECAP is performed to directly recycle metal scraps and reduce cost of material in engineering applications. The ECAP is one of the most important method in severe plastic deformation (SPD that can convert light metals into finished products. This paper reviews several experimental and numerical works that have been done to investigate the effects of the ECAP parameters such as die angles, material properties, outer corner angle, friction coefficient, temperature, size of chips, pressing force, ram speed and direct effects of number of passes on the strain distributions. It also includes the performance enhancement of aluminium matrix composite reinforced ceramic-based particles that derived from direct recycled aluminium chips for sustainable manufacturing practices.

  15. An experimental study on joining of severe plastic deformed aluminium materials with friction welding method

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Mumin [Mechanical Engineering Department, Trakya University, 22030 Edirne (Turkey)], E-mail: mumins@trakya.edu.tr; Erol Akata, H.; Ozel, Kaan [Mechanical Engineering Department, Trakya University, 22030 Edirne (Turkey)

    2008-07-01

    In this study, 5083 aluminium alloys, which were exposed to severe plastic deformation, were joined with friction welding method and the variation in mechanical properties of the joints was experimentally investigated. Severe plastic deformation methods can be classified as equal channel angular pressing (ECAP) (in other words, equal cross section lateral extrusion - ECSLE) and cyclic extrusion-compression. Aluminium alloy as test material 5083 and square cross-sectional equal channel angular pressing die for severe plastic deformation were used in the study. Firstly 5083 alloys, as purchased, were joined with friction welding method. The optimum parameters for friction time, upset time, friction pressure and upset pressure, which are necessary for welding, were obtained. Afterwards, 5083 aluminium materials as purchased were prepared as square cross-section and then 1-pass severe plastic deformation was applied to specimen by equal channel angular pressing die. The obtained parts as square form were prepared as cylindrical form by machining and then the parts were joined by continuous drive friction welding equipment that was designed and produced in laboratory conditions before. Later, the tensile strengths of the parts, obtained at optimum conditions, were compared with those of the joined parts as purchased form. Then, hardness variations and microstructures of joints were examined. Finally, the obtained results were commented on.

  16. Orientation correlations in aluminium deformed by ECAE

    DEFF Research Database (Denmark)

    Bowen, Jacob R.; Mishin, Oleg; Prangnell, P.B.

    2002-01-01

    Distributions of boundary misorientations measured in an Al–0.13%Mg alloy, processed by equal channel angular extrusion to a von Mises effective strain of 10, have been compared to misorientation distributions generated from a random mix of orientations present in the microstructure. A significan...

  17. Improving the automated optimization of profile extrusion dies by applying appropriate optimization areas and strategies

    Science.gov (United States)

    Hopmann, Ch.; Windeck, C.; Kurth, K.; Behr, M.; Siegbert, R.; Elgeti, S.

    2014-05-01

    The rheological design of profile extrusion dies is one of the most challenging tasks in die design. As no analytical solution is available, the quality and the development time for a new design highly depend on the empirical knowledge of the die manufacturer. Usually, prior to start production several time-consuming, iterative running-in trials need to be performed to check the profile accuracy and the die geometry is reworked. An alternative are numerical flow simulations. These simulations enable to calculate the melt flow through a die so that the quality of the flow distribution can be analyzed. The objective of a current research project is to improve the automated optimization of profile extrusion dies. Special emphasis is put on choosing a convenient starting geometry and parameterization, which enable for possible deformations. In this work, three commonly used design features are examined with regard to their influence on the optimization results. Based on the results, a strategy is derived to select the most relevant areas of the flow channels for the optimization. For these characteristic areas recommendations are given concerning an efficient parameterization setup that still enables adequate deformations of the flow channel geometry. Exemplarily, this approach is applied to a L-shaped profile with different wall thicknesses. The die is optimized automatically and simulation results are qualitatively compared with experimental results. Furthermore, the strategy is applied to a complex extrusion die of a floor skirting profile to prove the universal adaptability.

  18. 75 FR 80527 - Aluminum Extrusions From China

    Science.gov (United States)

    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...

  19. Residual stress and its effect on the mechanical properties of Y-doped Mg alloy fabricated via back-pressure assisted equal channel angular pressing (ECAP-BP)

    Czech Academy of Sciences Publication Activity Database

    Shen, J.; Gärtnerová, Viera; Kecskes, L.J.; Kondoh, K.; Jäger, Aleš; Wei, Q.

    2016-01-01

    Roč. 669, Jul (2016), s. 110-117 ISSN 0921-5093 R&D Projects: GA ČR GBP108/12/G043 Institutional support: RVO:68378271 Keywords : magnesium * equal channel angular pressing * ECAP * rare earth Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.094, year: 2016

  20. Microstructure and mechanical properties after annealing of equal-channel angular pressed interstitial-free steel

    International Nuclear Information System (INIS)

    Hazra, Sujoy S.; Pereloma, Elena V.; Gazder, Azdiar A.

    2011-01-01

    The evolution of microstructure, microtexture and mechanical properties during isothermal annealing of an ultrafine-grained interstitial-free steel after eight passes of route B C room temperature equal-channel angular pressing (ECAP) was studied. The microstructure and microtexture were characterized by electron back-scattering diffraction, and mechanical properties were assessed by shear punch and uniaxial tensile testing. Homogeneous coarsening via continuous recrystallization of the ECAP microstructure is accompanied by minor changes in the ∼63% high-angle boundary population and a sharpening of the original ECAP texture. This is followed by abnormal growth during the final stages of softening due to local growth advantages. Linear correlations between shear and tensile data were established for yield, ultimate strength and total elongation. After yield, the changes in uniaxial tensile behaviour from geometrical softening after ECAP to load drop, Lueders banding and continuous yielding after annealing is attributable to a coarsening of the microstructure.

  1. Processing of a magnesium alloy by equal-channel angular pressing using a back-pressure

    International Nuclear Information System (INIS)

    Xu Cheng; Xia Kenong; Langdon, Terence G.

    2009-01-01

    Experiments were conducted on the magnesium AZ31 alloy to evaluate the significance of conducting equal-channel angular pressing (ECAP) with a back-pressure. Following processing by ECAP, the values of the Vickers microhardness were recorded on the cross-sectional planes and microstructural observations were undertaken using transmission electron microscopy. The results show an increase in the hardness in the first pass with significant microstructural inhomogeneity and a transition towards a more homogeneous structure with subsequent passes. The grain size was measured as ∼0.9 μm after 8 passes. A comparison with published data on the same alloy processed by ECAP without a back-pressure suggests several advantages in incorporating a back-pressure into ECAP. These advantages include the ability to achieve greater grain refinement, a potential for pressing at lower temperatures and the development of a more rapid evolution towards a homogeneous microstructure.

  2. Angular correlations in top quark decays in standard model extensions

    International Nuclear Information System (INIS)

    Batebi, S.; Etesami, S. M.; Mohammadi-Najafabadi, M.

    2011-01-01

    The CMS Collaboration at the CERN LHC has searched for the t-channel single top quark production using the spin correlation of the t-channel. The signal extraction and cross section measurement rely on the angular distribution of the charged lepton in the top quark decays, the angle between the charged lepton momentum and top spin in the top rest frame. The behavior of the angular distribution is a distinct slope for the t-channel single top (signal) while it is flat for the backgrounds. In this Brief Report, we investigate the contributions which this spin correlation may receive from a two-Higgs doublet model, a top-color assisted technicolor (TC2) and the noncommutative extension of the standard model.

  3. Hydrostatic extrusion of magnesium alloys

    NARCIS (Netherlands)

    Sillekens, W.H.; Bohlen, J.

    2012-01-01

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

  4. Spatially multiplexed orbital-angular-momentum-encoded single photon and classical channels in a free-space optical communication link.

    Science.gov (United States)

    Ren, Yongxiong; Liu, Cong; Pang, Kai; Zhao, Jiapeng; Cao, Yinwen; Xie, Guodong; Li, Long; Liao, Peicheng; Zhao, Zhe; Tur, Moshe; Boyd, Robert W; Willner, Alan E

    2017-12-01

    We experimentally demonstrate spatial multiplexing of an orbital angular momentum (OAM)-encoded quantum channel and a classical Gaussian beam with a different wavelength and orthogonal polarization. Data rates as large as 100 MHz are achieved by encoding on two different OAM states by employing a combination of independently modulated laser diodes and helical phase holograms. The influence of OAM mode spacing, encoding bandwidth, and interference from the co-propagating Gaussian beam on registered photon count rates and quantum bit error rates is investigated. Our results show that the deleterious effects of intermodal crosstalk effects on system performance become less important for OAM mode spacing Δ≥2 (corresponding to a crosstalk value of less than -18.5  dB). The use of OAM domain can additionally offer at least 10.4 dB isolation besides that provided by wavelength and polarization, leading to a further suppression of interference from the classical channel.

  5. X-ray microbeam measurements of long-range internal stresses in commercial-purity aluminum processed by multiple passes of equal-channel angular pressing

    International Nuclear Information System (INIS)

    Phan, Thien Q.; Lee, I-Fang; Levine, Lyle E.; Tischler, Jonathan Z.; Huang, Yi; Fox, Alan G.; Langdon, Terence G.; Kassner, Michael E.

    2014-01-01

    X-ray microbeam diffraction was used to measure long-range internal stresses (LRISs) in the grain/subgrain interiors of commercial-purity aluminum processed by equal-channel angular pressing for up to eight passes. The LRIS values at +4.9° off the axial (pressing) direction show only a slight increase with increasing numbers of passes. The normalized stress remains approximately constant at ∼0.10 of the flow stress

  6. How extrusion shapes food processing

    Science.gov (United States)

    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 ...

  7. The angular momentum dependence of complex fragment emission

    International Nuclear Information System (INIS)

    Sobtka, L.G.; Sarantites, D.G.; Li, Z.

    1987-01-01

    Large fragment (A > 4) production at high angular momentum is studied via the reaction, 200 MeV 45 Sc + 65 Cu. Comparisons of the fragment yields from this reaction (high angular momentum) to those from 93 Nb + Be (low angular momentum) are used to verify the strong angular momentum dependence of large fragment production predicted by equilibrium models. Details of the coincident γ-ray distributions not only confirm a rigidly rotating intermediate but also indicate that the widths of the primary L-wave distributions decrease with increasing symmetry in the decay channel. These data are used to test the asymmetry and L-wave dependence of emission barriers calculated from a rotating, finite range corrected, liquid drop model. 21 refs., 10 figs

  8. Shear bands and anisotropy of the mechanical properties of an MA2-1pch magnesium alloy after equal-channel angular pressing

    Science.gov (United States)

    Serebryany, V. N.; Khar'kova, M. A.; D'yakonov, G. S.; Kopylov, V. I.; Dobatkin, S. V.

    2017-10-01

    Effect of structure and texture on the anisotropy of the mechanical properties of the MA2-1pch magnesium alloy subjected to equal-channel angular pressing and subsequent annealing has been studied in two mutually perpendicular planes Y and X (along and across the pressing direction). The anisotropy of the mechanical properties is shown to be due to various orientations of shear bands and various types of texture inside the bands and outside them in planes X and Y.

  9. Microstructural and mechanical characteristics of EUROFER'97 processed by equal channel angular pressing

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, P., E-mail: pilar.fernandez@ciemat.es [National Fusion Laboratory, CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain); Eddahbi, M.; Auger, M.A.; Leguey, T.; Monge, M.A.; Pareja, R. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

    2011-10-01

    EUROFER'97 was processed by equal channel angular pressing (ECAP) at 823 K for a total of 4 or 8 passes, using a die angle of 105{sup o}, and its microstructure and tensile behavior in temperature range 568-873 K investigated. A single ECAP pass developed a deformation texture {l_brace}1 1 0{r_brace} <0 1 1> that was practically stable during subsequent ECAP passes. The materials processed by 1 or 2 passes exhibited a fine microstructure of recovered subgrains and tensile behavior very similar to that for the tempered material in the as-received condition. The materials processed using 4 or 8 passes exhibited nearly equiaxial submicron grained structures with a high density of high-angle grain boundaries. These materials became softer than the as-received material at a testing temperature of {approx}823 K. EUROFER ECAP processed under the present conditions exhibited hardening ratio somewhat higher than that of the as-received material.

  10. Observation of Anisotropy of Creep Fracture Using Small Punch Test for Al-Al4C3 System Produced by Equal Channel Angular Pressing

    Czech Academy of Sciences Publication Activity Database

    Besterci, M.; Dobeš, Ferdinand; Ballóková, B.; Sülleiová, K.; Kvačkaj, T.

    2011-01-01

    Roč. 30, č. 3 (2011), s. 205-210 ISSN 0334-6455 R&D Projects: GA AV ČR 1QS200410502; GA AV ČR IAA200410801 Grant - others:Vega(SK) 2/0025/11 Institutional research plan: CEZ:AV0Z20410507 Keywords : Equal channel angular pressing * small-punch creep * fracture * metal-matrix composites Subject RIV: JI - Composite Materials Impact factor: 0.242, year: 2011

  11. Influences of crystallographic orientations on deformation mechanism and grain refinement of Al single crystals subjected to one-pass equal-channel angular pressing

    International Nuclear Information System (INIS)

    Han, W.Z.; Zhang, Z.F.; Wu, S.D.; Li, S.X.

    2007-01-01

    The influences of crystallographic orientations on the evolution of dislocation structures and the refinement process of sub-grains in Al single crystals processed by one-pass equal-channel angular pressing (ECAP) were systematically investigated by means of scanning electron microscopy, electron backscatter diffraction and transmission electron microscopy. Three single crystals with different orientations, denoted as crystal I, crystal II and crystal III, were specially designed according to the shape of the ECAP die. For crystal I, its insert direction is parallel to [1 1 0] and its extrusion direction is parallel to [1-bar11]. For crystal II, the (1-bar11) plane is located parallel to the intersection plane of the ECAP die, and the [1 1 0] direction is along the general shear direction on the intersection plane. For crystal III, the (1-bar11) plane is laid on the plane perpendicular to the intersection of the ECAP die, and the [1 1 0] direction is vertical to the general shear direction. For crystal I, abundant cell block structures with multi-slip characters were formed, and they should be induced by four symmetric slip systems, while for crystal II, there are two sets of sub-grain structures with higher misorientation, making an angle of ∼70 deg., which can be attributed to the interactions of the two asymmetric primary slip planes, whereas for crystal III, only one set of ribbon structures was parallel to the traces of (1-bar11) with the lowest misorientation angle among the three single crystals, which should result from the homogeneous slip on the primary slip plane. The different microstructural features of the three single crystals provide clear experimental evidence that the microstructures and misorientation evolution are strongly affected by the crystallographic orientation or by the interaction between shear deformation imposed by the ECAP die and the intrinsic slip deformation of the single crystals. Based on the experimental results and the

  12. Natural roller bearing fault detection by angular measurement of true instantaneous angular speed

    Science.gov (United States)

    Renaudin, L.; Bonnardot, F.; Musy, O.; Doray, J. B.; Rémond, D.

    2010-10-01

    The challenge in many production activities involving large mechanical devices like power transmissions consists in reducing the machine downtime, in managing repairs and in improving operating time. Most online monitoring systems are based on conventional vibration measurement devices for gear transmissions or bearings in mechanical components. In this paper, we propose an alternative way of bearing condition monitoring based on the instantaneous angular speed measurement. By the help of a large experimental investigation on two different applications, we prove that localized faults like pitting in bearing generate small angular speed fluctuations which are measurable with optical or magnetic encoders. We also emphasize the benefits of measuring instantaneous angular speed with the pulse timing method through an implicit angular sampling which ensures insensitivity to speed fluctuation. A wide range of operating conditions have been tested for the two applications with varying speed, load, external excitations, gear ratio, etc. The tests performed on an automotive gearbox or on actual operating vehicle wheels also establish the robustness of the proposed methodology. By the means of a conventional Fourier transform, angular frequency channels kinematically related to the fault periodicity show significant magnitude differences related to the damage severity. Sideband effects are evidently seen when the fault is located on rotating parts of the bearing due to load modulation. Additionally, slip effects are also suspected to be at the origin of enlargement of spectrum peaks in the case of double row bearings loaded in a pure radial direction.

  13. Dynamic ageing and the mechanical response of Al-Mg-Si alloy through equal channel angular pressing

    International Nuclear Information System (INIS)

    Vaseghi, Majid; Taheri, Ali Karimi; Hong, Sun Ig; Kim, Hyoung Seop

    2010-01-01

    In this paper, dynamic ageing characteristics associated with the application of equal channel angular pressing (ECAP) to Al6061 alloy at elevated temperatures was investigated. Followed by ECAP, Vickers microhardness measurement on the cross-sectional planes and microstructural observations were undertaken using transmission electron microscopy. The combination of the ECAP process with dynamic ageing at both 100 o C and 150 o C resulted in a significant increase in hardness. The grain size was measured as ∼160 nm after four passes. A comparison with the published data on the same alloy processed by ECAP at room temperature and statically aged, suggests several advantages in incorporating dynamic ageing with ECAP. These advantages consist of the ability to attain better grain refinement, increased hardness and the potential for saving time and energy.

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

    Energy Technology Data Exchange (ETDEWEB)

    Fan, X.H. [State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240 (China); School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Tang, D., E-mail: tangding@sjtu.edu.cn [State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240 (China); School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Fang, W.L.; Li, D.Y.; Peng, Y.H. [State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240 (China); School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

    2016-08-15

    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 recrystallization 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.

  15. Friction measurement and modelling in forward rod extrusion

    DEFF Research Database (Denmark)

    Tan, Xincai; Bay, Niels; Zhang, Wenqi

    2003-01-01

    Forward extrusion is one of the important processes in bulk metal forming. Friction stress can be estimated from the slope of the load±displacement curve at the steady state after the maximum load in a forward extrusion test. In this paper, forward rod extrusion tests are carried out to determine...... as the lubricant. Friction stresses are obtained from measurements of slopes of extrusion pressure±punch travel curves at the steady state stage. Normal pressures are evaluated by using Mohr’s circle, in which shear ¯ow stresses are estimated at the maximum elastic deformation points from the same extrusion...... pressure±punch travel curves. It is found that the relationship between normal pressure and friction stress appears linear, and therefore Coulomb’s friction model ®ts the experimental data very well. Extrusion pressure±punch travel curves before the steady state can be divided into four stages: elastic...

  16. Strain Localization during Equal-Channel Angular Pressing Analyzed by Finite Element Simulations

    Directory of Open Access Journals (Sweden)

    Tobias Daniel Horn

    2018-01-01

    Full Text Available Equal-Channel Angular Pressing (ECAP is a method used to introduce severe plastic deformation into a metallic billet without changing its geometry. In special cases, strain localization occurs and a pattern consisting of regions with high and low deformation (so-called shear and matrix bands can emerge. This paper studies this phenomenon numerically adopting two-dimensional finite element simulations of one ECAP pass. The mechanical behavior of aluminum is modeled using phenomenological plasticity theory with isotropic or kinematic hardening. The effects of the two different strain hardening types are investigated numerically by systematic parameter studies: while isotropic hardening only causes minor fluctuations in the plastic strain fields, a material with high initial hardening rate and sufficient strain hardening capacity can exhibit pronounced localized deformation after ECAP. The corresponding finite element simulation results show a regular pattern of shear and matrix bands. This result is confirmed experimentally by ECAP-processing of AA6060 material in a severely cold worked condition, where microstructural analysis also reveals the formation of shear and matrix bands. Excellent agreement is found between the experimental and numerical results in terms of shear and matrix band width and length scale. The simulations provide additional insights regarding the evolution of the strain and stress states in shear and matrix bands.

  17. Evaluation of Extrusion Technique for Nanosizing Liposomes

    Directory of Open Access Journals (Sweden)

    Sandy Gim Ming Ong

    2016-12-01

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

  18. The effect of high hydrostatic pressure on creep behaviour of pure Al and a Cu-0.2 wt% Zr alloy processed by equal-channel angular pressing

    Czech Academy of Sciences Publication Activity Database

    Dvořák, Jiří; Sklenička, Václav; Betekhtin, V. I.; Kadomtsev, A. G.; Král, Petr; Kvapilová, Marie; Svoboda, Milan

    2013-01-01

    Roč. 584, NOV (2013), s. 103-113 ISSN 0921-5093 R&D Projects: GA ČR(CZ) GAP108/11/2260; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Equal-channel angular processing * Nanostructured materials * Mechanical characterization * Electron microscopy * Grain boundaries Subject RIV: JG - Metallurgy Impact factor: 2.409, year: 2013

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

    Science.gov (United States)

    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.

  20. The donut and dynamic polarization effects in proton channeling through carbon nanotubes

    DEFF Research Database (Denmark)

    Borka, D.; Mowbray, Duncan; Miskovic, Z.L.

    2010-01-01

    We investigate the angular and spatial distributions of protons with an energy of 0.223 MeV after channeling them through an (11, 9) single-wall carbon nanotube of 0.2 mu m length. The proton incident angle is varied between 0 and 10 mrad, being close to the critical angle for channeling. We show...... that, as the proton incident angle increases and approaches the critical angle for channeling, a ring-like structure is developed in the angular distribution-the donut effect. We demonstrate that it is the rainbow effect. If the proton incident angle is between zero and half of the critical angle...... for channeling, the image force affects considerably the number and positions of the maxima of the angular and spatial distributions. However, if the proton incident angle is close to the critical angle for channeling, its influence on the angular and spatial distributions is considerably decreased. We...

  1. Aluminum extrusion with a deformable die

    NARCIS (Netherlands)

    Assaad, W.

    2010-01-01

    Aluminum extrusion process is one of metal forming processes. In aluminum extrusion, a work-piece (billet) is pressed through a die with an opening that closely resembles a desired shape of a profile. By this process, long profiles with an enormous variety of cross-sections can be produced to

  2. Influence of the Number of Passes under Equal-Channel Angular Pressing on the Elastic-Plastic Properties, Durability, and Defect Structure of the Al+0.2 wt % Sc Alloy

    Czech Academy of Sciences Publication Activity Database

    Betekhtin, V. I.; Sklenička, Václav; Saxl, Ivan; Kardashev, B. K.; Kadomtsev, A. G.; Narykova, M. V.

    52 2010, č. 8 (2010), s. 1629-1636 ISSN 1063-7834 Institutional research plan: CEZ:AV0Z20410507; CEZ:AV0Z10190503 Keywords : equal-channel angular pressing (ECAP) * severe plastic deformation * ultrafine-grained material * elastic-plastic properties Subject RIV: JG - Metallurgy Impact factor: 0.727, year: 2010

  3. Turbine airfoil fabricated from tapered extrusions

    Science.gov (United States)

    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.

  4. MODERNIZATION OF TECHNOLOGICAL LINE FOR CELLULAR EXTRUSION PROCESS

    Directory of Open Access Journals (Sweden)

    Tomasz Garbacz

    2014-06-01

    As part of the modernization of the cellular extrusion technology the extrusion head was designed and made. During the designing and modeling of the head the Auto CAD programe was used. After the prototyping the extrusion head was tested. In the article specification of cellular extrusion process of thermoplastics was presented. In the research, the endothermal chemical blowing agents in amount 1,0% by mass were used. The quantity of used blowing agent has a direct influence on density and structure of the extruded product of modified polymers. However, these properties have further influence on porosity, impact strength, hardness, tensile strength and another.

  5. Extrusion product defects: a statistical study

    International Nuclear Information System (INIS)

    Qamar, S.Z.; Arif, A.F.M.; Sheikh, A.K.

    2003-01-01

    In any manufacturing environment, defects resulting in rework or rejection are directly related to product cost and quality, and indirectly linked with process, tooling and product design. An analysis of product defects is therefore integral to any attempt at improving productivity, efficiency and quality. Commercial aluminum extrusion is generally a hot working process and consists of a series of different but integrated operations: billet preheating and sizing, die set and container preheating, billet loading and deformation, product sizing and stretching/roll-correction, age hardening, and painting/anodizing. Product defects can be traced back to problems in billet material and preparation, die and die set design and maintenance, process variable aberrations (ram speed, extrusion pressure, container temperature, etc), and post-extrusion treatment (age hardening, painting/anodizing, etc). The current paper attempts to analyze statistically the product defects commonly encountered in a commercial hot aluminum extrusion setup. Real-world rejection data, covering a period of nine years, has been researched and collected from a local structural aluminum extrusion facility. Rejection probabilities have been calculated for all the defects studied. The nine-year rejection data have been statistically analyzed on the basis of (i) an overall breakdown of defects, (ii) year-wise rejection behavior, (iii) breakdown of defects in each of three cost centers: press, anodizing, and painting. (author)

  6. Effect of equal channel angular pressing on the strength and ductility of an AZ80 alloy

    International Nuclear Information System (INIS)

    Pereira, T S; Chung, C W; Ding, R; Chiu, Y L

    2009-01-01

    Equal channel angular pressing (ECAP) was applied to an extruded AZ80 Mg alloy in order to refine microstructure and enhance mechanical properties. The results show that the initial grain size of 20 μm of the as-extruded samples has been reduced by 75% after the first pass of ECAP, down to about 5 μm. Also as a result of the severe plastic deformation, the intermetallic compound Mg 17 Al 12 , which was distributed along grain boundaries and forms networks before the ECAP, has been re-arranged into a more homogeneous distribution and with a more spherical shape after the ECAP. Although no strengthening effect has been observed, the grain refinement and precipitate fragmentation caused by the ECAP has resulted in a 28% increase in the elongation to failure in tensile tests. Fractography observation and texture measurement have also been carried out.

  7. Characterization of creep properties and creep textures in pure aluminum processed by equal-channel angular pressing

    International Nuclear Information System (INIS)

    Kawasaki, Megumi; Beyerlein, Irene J.; Vogel, Sven C.; Langdon, Terence G.

    2008-01-01

    High-purity aluminum was processed by equal-channel angular pressing (ECAP) and then tested under creep conditions at 473 K. The results show conventional power-law creep with a stress exponent of n = 5 which is consistent with an intragranular dislocation process involving the glide and climb of dislocations. It is demonstrated that diffusion creep is not important in these tests because the ultrafine grains produced by ECAP are not stable at this temperature. Texture measurements were undertaken using the high-pressure preferred orientation neutron time-of-flight diffractometer and they reveal significant differences in the evolution of texture during creep in pressed and unpressed specimens. These experimental measurements of texture are in excellent agreement with theoretical textures predicted using a visco-plastic self-consistent model that limits deformation to plastic slip. The calculations provide additional confirmation that creep occurs through an intragranular dislocation process

  8. Extrusion processing : effects on dry canine diets

    NARCIS (Netherlands)

    Tran, Q.D.

    2008-01-01

    Keywords: Extrusion, Canine diet, Protein, Lysine, Starch gelatinization, Palatability, Drying.

    Extrusion cooking is a useful and economical tool for processing animal feed. This high temperature, short time processing technology causes chemical and physical changes that alter the

  9. Mechanical properties and biocorrosion resistance of the Mg-Gd-Nd-Zn-Zr alloy processed by equal channel angular pressing.

    Science.gov (United States)

    Zhang, Junyi; Kang, Zhixin; Wang, Fen

    2016-11-01

    A Mg-Gd-Nd-Zn-Zr alloy was processed by equal channel angular pressing (ECAP) at 375°C. The grain size of Mg-Gd-Nd-Zn-Zr alloy was refined to ~2.5μm with the spherical precipitates (β1 phase) distributing in the matrix. The mechanical properties of ECAPed alloy were significantly improved as a result of the grain refinement and precipitation strengthening. The corrosion rate of the ECAPed magnesium alloy in simulated body fluid dramatically decreased from 0.236mm/a to 0.126mm/a due to the strong basal texture and refined microstructure. This wrought magnesium alloy shows potentials in biomedical application. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Orbital Angular Momentum Multiplexing over Visible Light Communication Systems

    Science.gov (United States)

    Tripathi, Hardik Rameshchandra

    This thesis proposes and explores the possibility of using Orbital Angular Momentum multiplexing in Visible Light Communication system. Orbital Angular Momentum is mainly applied for laser and optical fiber transmissions, while Visible Light Communication is a technology using the light as a carrier for wireless communication. In this research, the study of the state of art and experiments showing some results on multiplexing based on Orbital Angular Momentum over Visible Light Communication system were done. After completion of the initial stage; research work and simulations were performed on spatial multiplexing over Li-Fi channel modeling. Simulation scenarios which allowed to evaluate the Signal-to-Noise Ratio, Received Power Distribution, Intensity and Illuminance were defined and developed.

  11. Channeling of molecular ions with relativistic energy

    International Nuclear Information System (INIS)

    Azuma, Toshiyuki; Muranaka, Tomoko; Kondo, Chikara; Hatakeyama, Atsushi; Komaki, Kenichiro; Yamazaki, Yasunori; Takabayashi, Yuichi; Murakami, Takeshi; Takada, Eiichi

    2003-01-01

    When energetic ions are injected into a single crystal parallel to a crystal axis or plane, they proceed in an open space guided by the crystal potential without colliding with atoms in the atomic plane or string, which is called channeling. We aimed to study dynamics of molecular ions, H 2 + , of 160 MeV/u and their fragment ions, H + ions in a Si crystal under the channeling condition. The molecular ions, H 2 + , are soon ionized, i.e. electron-stripped in the crystal, and a pair of bare nuclei, H + ions, travels in the crystal potential with mutual Coulomb repulsion. We developed a 2D position sensitive detector for the angular-distribution measurement of the H + ions transmitted through the crystal, and observed the detailed angular distribution. In addition we measured the case of H + on incidence for comparison. As a result, the channeled component and non-channeling were clearly separated. The incident angular divergence is critical to discuss the effect of Coulomb explosion of molecular H 2 + ions. (author)

  12. Zr Extrusion – Direct Input for Models & Validation

    Energy Technology Data Exchange (ETDEWEB)

    Cerreta, Ellen Kathleen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-07

    As we examine differences in the high strain rate, high strain tensile response of high purity, highly textured Zr as a function of loading direction, temperature and extrusion velocity with primarily post mortem characterization techniques, we have also developed a technique for characterizing the in-situ extrusion process. This particular measurement is useful for partitioning energy of the system during the extrusion process: friction, kinetic energy, and temperature

  13. Residence time modeling of hot melt extrusion processes.

    Science.gov (United States)

    Reitz, Elena; Podhaisky, Helmut; Ely, David; Thommes, Markus

    2013-11-01

    The hot melt extrusion process is a widespread technique to mix viscous melts. The residence time of material in the process frequently determines the product properties. An experimental setup and a corresponding mathematical model were developed to evaluate residence time and residence time distribution in twin screw extrusion processes. The extrusion process was modeled as the convolution of a mass transport process described by a Gaussian probability function, and a mixing process represented by an exponential function. The residence time of the extrusion process was determined by introducing a tracer at the extruder inlet and measuring the tracer concentration at the die. These concentrations were fitted to the residence time model, and an adequate correlation was found. Different parameters were derived to characterize the extrusion process including the dead time, the apparent mixing volume, and a transport related axial mixing. A 2(3) design of experiments was performed to evaluate the effect of powder feed rate, screw speed, and melt viscosity of the material on the residence time. All three parameters affect the residence time of material in the extruder. In conclusion, a residence time model was developed to interpret experimental data and to get insights into the hot melt extrusion process. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Subbarrier fusion of 16O+112Cd: Cross sections and mean angular momenta

    International Nuclear Information System (INIS)

    Ackermann, D.; Corradi, L.; Napoli, D.R.; Petrache, C.M.; Spolaore, P.; Stefanini, A.M.; Scarlassara, F.; Beghini, S.; Montagnoli, G.; Segato, G.F.; Signorini, C.

    1994-01-01

    Fusion cross sections and mean angular momenta have been measured for 16 O+ 112 Cd around the Coulomb barrier. The experimental results are well reproduced by coupled-channels calculations, confirming the validity of this model for mass-asymmetric systems. The predicted asymptotic behaviour of the mean angular momentum at low energies has been observed. ((orig.))

  15. Microstructure and mechanical properties of Pb-4%Sb alloy processed by equal channel angular pressing

    Directory of Open Access Journals (Sweden)

    Roberto Braga Figueiredo

    2006-03-01

    Full Text Available Equal Channel Angular Pressing (ECAP is the most prominent SPD (Severe Plastic Deformation method for the production of ultrafine and nanostructured metals, and has been extensively employed and analyzed. This technique was applied to a Pb-4%Sb alloy at room temperature, in order to study its effect on a low melting point and multiphase metallic material. The material was subjected to effective strains higher than 9, after 8 passes of processing, where dynamic and static recrystallization are expected during and after each pass. This eliminates any grain refinement and allows the analysis only of the microstructural effects associated with second phase redistribution and eventual precipitate dissolution. ECAP followed route C, which eliminates structural alignment after each even ECAP pass, facilitating the study of the microstructural evolution. It is shown that three ECAP passes are necessary to completely break the lamellar structure of the as cast strucure and that antimony dissolves into the lead rich matrix. Dynamic recrystallization and structural changes reduce the material strength and change the flow curve format.

  16. Effect of regimes of equal-channel angular pressing on the superplasticity of aluminium alloy 1420

    International Nuclear Information System (INIS)

    Islamgaliev, R.K.; Yunusova, N.F.; Valiev, R.Z.

    2002-01-01

    Investigation results on the influence of conditions of equal-channel angular pressing (EAP) on structure and superplasticity of aluminium alloy 1420 (Al-5.5%Mg-2.2%Li-0.12%Zr) are reported. It is revealed that the superplasticity of alloy 1420 is determined not only by fine grains (less than 1 μm), but its structural and phase state as well. The structural phase state is shown to be greatly dependent on EAP conditions. In particular, the structure of specimens prepared using the optimal EAP conditions is characterized by a mean grain size (0.8 μm) of the matrix with predominantly high-angle disorientations as well as by presence of secondary phase Al 2 MgLi and AlLi particles with of 0.3 μm and 0.4 μm size respectively. It is shown that the rods with an optimal structural phase state exhibit record-breaking for the alloy elongation to fracture equal to 1620% at 400 Deg C and at strain rate of 10 -2 s -1 [ru

  17. Material testing of copper by extrusion-cutting

    DEFF Research Database (Denmark)

    Segalina, F.; De Chiffre, Leonardo

    2017-01-01

    was developed and implemented on a CNC lathe. An investigation was carried out extrusion-cutting copper discs using high-speed-steel cutting tools at 100 m/min cutting speed. Flow stress values for copper under machining-relevant conditions were obtained from measurement of the extrusion-cutting force...

  18. Nano grained AZ31 alloy achieved by equal channel angular rolling process

    International Nuclear Information System (INIS)

    Hassani, F.Z.; Ketabchi, M.

    2011-01-01

    Equal channel angular rolling (ECAR) is a severe plastic deformation process which is carried out on large, thin sheets. The grain size could be significantly decreased by this process. The main purpose of this study is to investigate the possibility of grain refinement of AZ31 magnesium alloy sheet by this process to nanometer. The effect of the number of ECAR passes on texture evolution of AZ31 magnesium alloy was investigated. ECAR temperature was controlled to maximize the grain refinement efficiency along with preventing cracking. The initial microstructure of as-received AZ31 sheet showed an average grain size of about 21 μm. The amount of grain refinement increased with increasing the pass number. After 10 passes of the process, significant grain refinement occurred and the field emission scanning electron microscopic (FESEM) micrographs showed that the size of grains were decreased significantly to about 14-70 nm. These grains were formed at the grain boundaries and inside some of the previous larger micrometer grains. Observation of optical microstructures and X-ray diffraction patterns (XRD) showed the formation of twins after ECAR process. Micro-hardness of material was studied at room temperature. There was a continuous enhancement of hardness by increasing the pass number of ECAR process. At the 8th pass, hardness values increased by 53%. At final passes hardness reduced slightly, which was attributed to saturation of strain in high number of passes.

  19. Long-term thermal stability of Equal Channel Angular Pressed 2024 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Güher, E-mail: guherkotan@gmail.com [Middle East Technical University, Metallurgical and Materials Engineering Department, 06800 Ankara (Turkey); Mersin University, Metallurgical and Materials Engineering Department, 33343 Yenisehir, Mersin (Turkey); Kalay, Y. Eren; Gür, C. Hakan [Middle East Technical University, Metallurgical and Materials Engineering Department, 06800 Ankara (Turkey)

    2016-11-20

    The strength of bulk metallic materials can be improved by creating ultra-fine grained structure via severe plastic deformation (SPD). However, the thermal stability of severely deformed materials has been a major issue that restricts their practical use within the industry. Although there are studies on the thermal stability of SPD metals, the long-term annealing response of particularly complex alloys, such as the age hardenable ones, remains undetermined. In the present study, annealing behavior of the single-pass Equal Channel Angular Pressed age hardenable 2024 Al alloy was investigated in the 0.38–0.52 homologous temperature range for up to 1000 h. Microstructures and the corresponding mechanical properties of the samples were determined by transmission electron microscopy, electron back-scatter diffraction analyses, and micro-hardness measurements. After long annealing durations at 80 °C and 120 °C, a secondary hardening was observed whereas a fast softening occurred at 200 °C. At 150 °C, however, a softening followed by a slight secondary hardening was also detected. The increased coarsening rate of S precipitates accompanied with dislocation annihilation was found to be the major cause of the hardness loss. Furthermore, dislocation-rich structure and Mg clusters remaining from the S precipitate dissolution eased the nucleation of Ω precipitates which are responsible for the secondary hardening. It was concluded that below 120 °C the single pass ECAPed Al 2024 components preserve their improved hardness for a prolonged period of time.

  20. EVOLUTION OF MICROSTRUCTURE AND MECHANICAL PROPERTIES OF ULTRA-FINE-GRAINED INTERSTITIAL-FREE STEEL PROCESSED BY EQUAL CHANNEL ANGULAR PRESSING

    Directory of Open Access Journals (Sweden)

    Tomáš Krajňák

    2013-04-01

    Full Text Available Equal channel angular pressing (ECAP is one of the severe plastic deformation techniques which is widely used for producing metals with ultra-fine-grained microstructures. In the present work the influence of number of pressing by route BC on grain size, evolution of microstructure and mechanical properties of interstitial-free (IF steel has been investigated by means of optical microscopy, electron back-scattering diffraction (EBSD and tensile tests. It has been found, that the grain size decreases with increasing number of passes. Simultaneously tensile strength increases. The thermal stability of ECAP-processed microstructures has been also examined. It was found that the degradation of mechanical properties occurs only above 600 ˚C and 700 ˚C.

  1. Grain Refinement and High-Performance of Equal-Channel Angular Pressed Cu-Mg Alloy for Electrical Contact Wire

    Directory of Open Access Journals (Sweden)

    Aibin Ma

    2014-12-01

    Full Text Available Multi-pass equal-channel angular pressing (EACP was applied to produce ultrafine-grained (UFG Cu-0.2wt%Mg alloy contact wire with high mechanical/electric performance, aim to overcome the catenary barrier of high-speed trains by maximizing the tension and improving the power delivery. Microstructure evolution and overall properties of the Cu-Mg alloy after different severe-plastic-deformation (SPD routes were investigated by microscopic observation, tensile and electric tests. The results show that the Cu-Mg alloy after multi-pass ECAP at 473 K obtains ultrafine grains, higher strength and desired conductivity. More passes of ECAP leads to finer grains and higher strength, but increasing ECAP temperature significantly lower the strength increment of the UFG alloy. Grain refinement via continuous SPD processing can endow the Cu-Mg alloy superior strength and good conductivity characteristics, which are advantageous to high-speed electrification railway systems.

  2. Channeling of protons through radial deformed carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Borka Jovanović, V., E-mail: vborka@vinca.rs [Atomic Physics Laboratory (040), Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Borka, D. [Atomic Physics Laboratory (040), Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Galijaš, S.M.D. [Faculty of Physics, University of Belgrade, P.O. Box 368, 11001 Belgrade (Serbia)

    2017-05-18

    Highlights: • For the first time we presented theoretically obtained distributions of channeled protons with radially deformed SWNT. • Our findings indicate that influence of the radial deformation is very strong and it should not be omitted in simulations. • We show that the spatial and angular distributions depend strongly of level of radial deformation of nanotube. • Our obtained results can be compared with measured distributions to reveal the presence of various types of defects in SWNT. - Abstract: In this paper we have presented a theoretical investigation of the channeling of 1 GeV protons with the radial deformed (10, 0) single-wall carbon nanotubes (SWNTs). We have calculated channeling potential within the deformed nanotubes. For the first time we presented theoretically obtained spatial and angular distributions of channeled protons with radially deformed SWNT. We used a Monte Carlo (MC) simulation technique. We show that the spatial and angular distributions depend strongly of level of radial deformation of nanotube. These results may be useful for nanotube characterization and production and guiding of nanosized ion beams.

  3. Extrusion of the uranium-0.75 weight percent titanium alloy

    International Nuclear Information System (INIS)

    Jackson, R.J.; Lundberg, M.R.; Boland, J.F.

    1975-01-01

    Procedures are described for extruding the U--0.75 wt percent Ti alloy in the high alpha region (600 to 640 0 C) , and in the upper gamma region (900 to 1000 0 C). The casting of sound extrusion billets has importance in the production of sound extrusions, and procedures are given for casting sound billets up to 1,100 kilograms . Also important in producing sound extrusions is the use of glass lubricants. Reduction ratios of greater than 50 to 1 were achieved on reasonably sized billets. Extrusion constants of 48,000 pounds per square inch (psi) [296 megapascals (MPa)] for alpha phase (630 0 C) and 8,000 psi (56 MPa) for gamma phase (950 0 C) were achieved. Gamma-phase extrusion has preference over alpha-phase extrusion in that larger billets can be used and temperature control is not as critical. However alpha-phase extrusion offers better surface finish, less die wear, and fewer oxidation problems. Billets up to 14 inches in diameter have been successfully gamma-extruded and plans exist for extruding billets up to 20 inches (508 millimetres) in diameter. (U.S.)

  4. Towards predictive control of extrusion weld seams: an integrated approach

    NARCIS (Netherlands)

    Bakker, A.J. den; Werkhoven, R.J.; Sillekens, W.H.; Katgerman, L.

    2010-01-01

    Longitudinal weld seams are an intrinsic feature in hollow extrusions produced with porthole dies. The formation of longitudinal weld seams is a solid bonding process, controlled by the local conditions in the extrusion die. Being the weakest areas within the extrusion cross section, it is desirable

  5. Texture evolution during tensile necking of copper processed by equal channel angular extrusion

    DEFF Research Database (Denmark)

    Pantleon, Wolfgang; Richter, S.; Martin, S.

    2010-01-01

    Two copper samples, pre-deformed in tension to 5% plastic strain, are subjected to an in situ tensile deformation of 1% plastic strain while X-ray peak profiles from individual bulk grains are obtained. One sample is oriented with the in situ tensile axis parallel to the pre-deformation axis......, and peak profiles are obtained with the scattering vector parallel to this direction. The profiles show the expected asymmetry explained by the composite model as caused by intra-grain stresses. The other sample is oriented with the in situ tensile axis perpendicular to the pre-deformation axis, and peak...

  6. Development of Nanostructured Materials with Improved Radiation Tolerance for Advanced Nuclear Systems

    International Nuclear Information System (INIS)

    Zinghang Zhang; Hartwig, K. Ted

    2009-01-01

    This project will explore the fundamental mechanisms through which interfaces in nanolayered structures and grain boundaries of bulk nanomaterials are able to attract and rapidly eliminate point defects and unwanted foreign species. Candidate materials that will be studied include both nanostructured multilayer composites synthesized by magnetron sputtering and structural bulk nanomaterials produced by severed plastic deformation, equal channel angular extrusion

  7. Biomarker selection for determining bone biocompatibility of pure magnesium processed by equal channel angular pressing (ECAP) using immunohistochemistry

    Science.gov (United States)

    Handayani, Lisa; Sulistyani, Lilies Dwi; Supriadi, Sugeng; Priosoeryanto, Bambang Pontjo; Latief, Benny Syariefsyah

    2018-02-01

    Since grain refinement is proved to be favorable to improve mechanical properties and corrosion resistance, a new conceptual metal forming process, equal channel angular pressing (ECAP), has been carried out on magnesium, a very promising biodegradable material in the field of oral and maxillofacial surgery. The popularity of immunohisto-chemistry (IHC) has been rising following the discovery of biomarker. In the meantime, more antibodies being produced for research have been continuously rising and becoming more varied. This review provides a conceptual framework to understand the roles of IHC on determination of bone biocompatibility to ECAP magnesium by selecting biomarker and point needed to either select or make an antibody to the target. From the review, it has been concluded that the most suitable biomarkers for biocompatibility test of bone implanted with ECAP magnesium are collagen-1, osteocalcin, smooth muscle actin, and CD68.

  8. Microstructural evolution of Fe-rich particles in an Al-Zn-Mg-Cu alloy during equal-channel angular pressing

    International Nuclear Information System (INIS)

    Sha, G.; Wang, Y.B.; Liao, X.Z.; Duan, Z.C.; Ringer, S.P.; Langdon, T.G.

    2010-01-01

    The microstructures of a severely deformed Al-Zn-Mg-Cu (AA7136) alloy have been characterized carefully using transmission electron microscopy and three-dimensional atom probe analysis. The Fe-rich intermetallic particles are predominantly Al 13 Fe 4 type in the as-extruded alloy. Significantly, equal-channel angular pressing (ECAP) at 200 deg. C refines Fe-rich particles from ∼1 to 2 μm to as small as ∼50 nm after 4 passes processing, and effectively narrow down their size distribution with the increase of number of ECAP passes. In addition, small Fe-rich particles evolve into spherical morphology and are in a more uniform distribution. The formations of Fe-rich phases in AA7136, the kinetic and thermodynamic effects in relation to the refinement of Fe-rich particles and their morphology evolution during ECAP processing are discussed.

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

    International Nuclear Information System (INIS)

    Na, Geum Ju; Jang, Myung Geun; Kim, Jong Bong

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-15

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

  11. The friction influence on stress in micro extrusion

    Directory of Open Access Journals (Sweden)

    J. Piwnik

    2010-01-01

    Full Text Available Manufacturing of metallic parts by forming methods is industrially widespread due to high production rate, high accuracy, dimension’s and shape’s repeatability and good surface quality. The application of metal extrusion methods for the production of micro parts is possible, but there are some technological problems caused by small dimensions. Size effect is appearing. One of size effect symptom in micro extrusion, is a significant influence of rough contact between workpiece and tool while processing. In the case of rough contact without friction, material flows in the vicinity of the die surface. In order to explain more accurately a friction distribution in this area, the plastic wave friction model is proposed. This paper analyses specifications of a metal extrusion in micro scale. Using the friction model, a substitute friction shear factor mz and its influence on extrusion loading curves is determined in relationship to size of asperities.

  12. Experimental and numerical investigation of ram extrusion of bread dough

    Science.gov (United States)

    Mohammed, M. A. P.; Wanigasooriya, L.; Charalambides, M. N.

    2016-10-01

    An experimental and numerical study on ram extrusion of bread dough was conducted. A laboratory ram extrusion rig was designed and manufactured, where dies with different angles and exit radii were employed. Rate dependent behaviour was observed from tests conducted at different extrusion speeds, and higher extrusion pressure was reported for dies with decreasing exit radius. A finite element simulation of extrusion was performed using the adaptive meshing technique in Abaqus. Simulations using a frictionless contact between the billet and die wall showed that the model underestimates the response at high entry angles. On the other hand, when the coefficient of friction value was set to 0.09 as measured from friction experiments, the dough response was overestimated, i.e. the model extrusion pressure was much higher than the experimentally measured values. When a critical shear stress limit, τmax, was used, the accuracy of the model predictions improved. The results showed that higher die angles require higher τmax values for the model and the experiments to agree.

  13. On strain-induced dissolution of θ' and θ particles in Al-Cu binary alloy during equal channel angular pressing

    International Nuclear Information System (INIS)

    Liu Zhiyi; Bai Song; Zhou Xuanwei; Gu Yanxia

    2011-01-01

    Research highlights: → θ' particles in Al-Cu binary alloy was found to dissolve more rapidly than θ particles. → The different dissolution behavior of the θ' and θ phase was thermodynamically analysed. → The critical radius and free energy barrier for the strain-induced dissolution were calculated. - Abstract: The deformable θ' particle in Al-Cu binary alloy was found to dissolve more rapidly than the indeformable θ particle due to an additional increasing strain energy accumulated in the deformed θ' plate as well as an increasing interface energy led by the formation of sub-boundary in the θ' plate and fragmentation of the particle during equal channel angular pressing (ECAP). The critical radius and the free energy barrier for the strain-induced dissolution of both θ' and θ particles were calculated.

  14. Annealing behavior and shape memory effect in NiTi alloy processed by equal-channel angular pressing at room temperature

    International Nuclear Information System (INIS)

    Shahmir, Hamed; Nili-Ahmadabadi, Mahmoud; Wang, Chuan Ting; Jung, Jai Myun; Kim, Hyoung Seop; Langdon, Terence G.

    2015-01-01

    A martensitic NiTi shape memory alloy was processed successfully by equal-channel angular pressing (ECAP) for one pass at room temperature using a core–sheath billet design. The annealing behavior and shape memory effect of the ECAP specimens were studied followed by post-deformation annealing (PDA) at 673 K for various times. The recrystallization and structural evolution during annealing were investigated by differential scanning calorimetry, dilatometry, X-ray diffraction, transmission electron microscopy and microhardness measurements. The results indicate that the shape memory effect improves by PDA after ECAP processing. Annealing for 10 min gives a good shape memory effect which leads to a maximum in recoverable strain of 6.9 pct upon heating where this is more than a 25 pct improvement compared with the initial state

  15. Fabricating tungsten crucibles by drawing and extrusion spinning

    International Nuclear Information System (INIS)

    Edstrom, C.M.

    1981-01-01

    The fabrication of seamless tungsten crucibles 127-mm ID x 265-mm high x 6.25-mm wall thickness (5 in. x 10 1/2 in. x 1/4 in.) involved three drawing operations and extrusion spinning. The success of the drawing operations came from a combination of low draw reduction percentage, generous draw radii, large punch-to-die clearance, and attention to drawing temperature. The extrusion spinning success related to good drawn-cup-to-spinning-mandrel fit prior to making the extrusion passes, removal of stress risers in the part prior to spinning, and special attention to part and mandrel temperature

  16. Die Defects and Die Corrections in Metal Extrusion

    Directory of Open Access Journals (Sweden)

    Sayyad Zahid Qamar

    2018-05-01

    Full Text Available Extrusion is a very popular and multi-faceted manufacturing process. A large number of products for the automotive, aerospace, and construction sectors are produced through aluminum extrusion. Many defects in the extruded products occur because of the conditions of the dies and tooling. The problems in dies can be due to material issues, design and manufacturing, or severe usage. They can be avoided by maintaining the billet quality, by controlling the extrusion process parameters, and through routine maintenance. Die problems that occur on a day-to-day basis are mostly repairable and are rectified through various types of die correction operations. These defects and repair operations have not been reported in detail in the published literature. The current paper presents an in-depth description of repairable die defects and related die correction operations in metal extrusion. All major die defects are defined and classified, and their causes, preventive measures, and die correction operations are described. A brief frequency-based statistical study of die defects is also carried out to identify the most frequent die corrections. This work can be of direct benefit to plant engineers and operators and to researchers and academics in the field of metal extrusion.

  17. CHARACTERIZATION OF NEW TOOL STEEL FOR ALUMINUM EXTRUSION DIES

    OpenAIRE

    José Britti Bacalhau; Fernanda Moreno Rodrigues; Rafael Agnelli Mesquita

    2014-01-01

    Aluminum extrusion dies are an important segment of application on industrial tools steels, which are manufactured in steels based on AISI H13 steel. The main properties of steels applied to extrusion dies are: wear resistance, impact resistance and tempering resistance. The present work discusses the characteristics of a newly developed hot work steel to be used on aluminum extrusion dies. The effects of Cr and Mo contents with respect to tempering resistance and the Al addition ...

  18. Enhanced Impact Toughness at Ambient Temperatures of Ultrafine-Grained Al-26 wt.% Si Alloy Produced by Equal-Channel Angular Pressing

    Science.gov (United States)

    Jiang, Jinghua; Yuan, Ting; Shi, Jun; Zhang, Lingling; Ma, Aibin; Song, Dan

    2018-05-01

    Overcoming general brittleness of hypereutectic Al-Si alloys is in urgent need for expanding their application in automotive, aerospace and construction industries. A unique phenomenon was observed that bulk ultrafine-grained Al-26 wt.% Si alloy, produced by severe plastic deformation via equal-channel angular pressing, exhibited higher toughness at the impact temperature of - 196 100 °C than the coarse-grained casting alloy. The improvement in impact toughness at all testing temperatures was mainly due to the homogeneous ultrafine-grained structure with the breakage of brittle primary silicon crystals, which generated more and deeper fracture dimples that consumed much higher fracture energy. It indicates the advantage of bulk ultrafine-grained Al-Si alloys and spurs their application interest at various ambient temperatures.

  19. Investigation of quantum states of fast electrons under planar channeling in silicon crystals

    International Nuclear Information System (INIS)

    Gridnev, V.I.; Kaplin, V.V.; Khlabutin, V.G.; Rozum, E.I.; Vorobiev, S.A.

    1987-01-01

    The angular distributions of (1.87 to 5.7) MeV electrons channeled in 2 μm Si crystals along (100), (110), and (111) atomic planes are measured. The half-width of measured angular distributions is defined by a critical Lindhard angle. A relation is obtained connecting those energies of electrons at which their angular distributions are similar for various atomic planes. The effect of a 'critical energy' under planar channeling of electrons is found and investigated. (author)

  20. Spectral distribution of radiation on plane and axial channeling of ultrarelativistic electrons

    International Nuclear Information System (INIS)

    Bazylev, V.A.; Glebov, V.I.; Zhevago, N.K.

    1980-01-01

    The spectral angular and polarization charactristics of the radiation from channeled ultrarelativistic electrons are calculated. Analytic expressions for the spectral-angular power density of the radiation are obtained for some realistic models of the continuous potential of the crystal planes and axes. A critical analysis is also presented of some existent results of the theory of radiation on channeling

  1. Surface channeling

    International Nuclear Information System (INIS)

    Sizmann, R.; Varelas, C.

    1976-01-01

    There is experimental evidence that swift light ions incident at small angles towards single crystalline surfaces can lose an appreciable fraction of their kinetic energy during reflection. It is shown that these projectiles penetrate into the bulk surface region of the crystal. They can travel as channeled particles along long paths through the solid (surface channeling). The angular distribution and the depth history of the re-emerged projectiles are investigated by computer simulations. A considerable fraction of the penetrating projectiles re-emerges from the crystal with constant transverse energy if the angle of incidence is smaller than the critical angle for axial channeling. Analytical formulae are derived based on a diffusion model for surface channeling. A comparison with experimental data exhibits the relevance of the analytical solutions. (Auth.)

  2. Machine for extrusion under vacuum

    International Nuclear Information System (INIS)

    Gautier, A.

    1958-01-01

    In a study of the behaviour of easily oxidised metals during the extrusion process, it is first necessary to find an effective mean of fighting corrosion, since this, even when barely detectable, has an important influence on the validity of the results recorded. The neatest and also the most efficient of all the methods tried consists in creating a vacuum around the test piece. Working on this principle, and at the same time respecting the conventional rules for extrusion tests (loading the sample after stabilisation at the testing temperature, differential measurements of lengthening, etc.) we found it necessary to construct an original machine. (author) [fr

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

    Science.gov (United States)

    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.

  4. FORMING TUBES AND RODS OF URANIUM METAL BY EXTRUSION

    Science.gov (United States)

    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.

  5. The donut and dynamic polarization effects in proton channeling through carbon nanotubes

    International Nuclear Information System (INIS)

    Borka, D; Petrovic, S; Neskovic, N; Mowbray, D J; Miskovic, Z L

    2010-01-01

    We investigate the angular and spatial distributions of protons with an energy of 0.223 MeV after channeling them through an (11, 9) single-wall carbon nanotube of 0.2 μm length. The proton incident angle is varied between 0 and 10 mrad, being close to the critical angle for channeling. We show that, as the proton incident angle increases and approaches the critical angle for channeling, a ring-like structure is developed in the angular distribution-the donut effect. We demonstrate that it is the rainbow effect. If the proton incident angle is between zero and half of the critical angle for channeling, the image force affects considerably the number and positions of the maxima of the angular and spatial distributions. However, if the proton incident angle is close to the critical angle for channeling, its influence on the angular and spatial distributions is considerably decreased. We demonstrate that an increase of the proton incident angle can lead to a significant rearrangement of the propagating protons within the nanotube. This effect may be used to locate atomic impurities in nanotubes as well as for creating nanosized proton beams to be used in materials science, biology and medicine.

  6. Functionality of extrusion--texturized whey proteins.

    Science.gov (United States)

    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.

  7. Cross sections and average angular momenta in the fusion of 28Si+94,100Mo and 58,64Ni+64Ni

    International Nuclear Information System (INIS)

    Ackermann, D.; Beghini, S.; Montagnoli, G.; Mueller, L.; Segato, G.F.; Soramel, F.; Signorini, C.

    1996-01-01

    Fusion cross sections and mean angular momenta have been measured for the four systems 28 Si+ 94,100 Mo and 58,64 Ni+ 64 Ni and can be explained in the framework of the coupled-channel (CC) approach. In particular the influence of 2n-transfer channels with positive Q-values shows up. The direct relation between excitation function and angular momenta has been verified. (orig.)

  8. Orthodontic extrusion in the transitional dentition: a simple technique.

    LENUS (Irish Health Repository)

    Darby, Laura J

    2009-11-01

    Extrusion of teeth may be necessary in cases of delayed eruption, primary retention, traumatically intruded teeth, or subgingivally fractured teeth. Removable appliances are advantageous, as anchorage is not as tooth-dependant as in the case of fixed appliances. They are cost-effective, operator friendly, and a valuable treatment option to consider in cases where extrusion of anterior teeth in the transitional dentition is necessary. The purpose of this paper was to describe a simple, cost-effective technique using a removable appliance for extrusion of incisors in the transitional dentition.

  9. Workability Limits of Magnesium Alloy AZ31B Subjected to Equal Channel Angular Pressing

    Science.gov (United States)

    Arun, M. S.; Chakkingal, Uday

    2018-03-01

    Equal channel angular pressing (ECAP) is an important severe plastic deformation process to produce ultrafine grained microstructures in metals and alloys. Magnesium and its alloys generally possess poor workability at temperatures below 250 °C. This investigation examines the influence of different passes and processing routes of ECAP on improving the workability of Mg alloy AZ31B. ECAP was carried out for three passes using a die of angle 120° using processing routes Bc and C. The operating temperature was 523 K for the first pass and 423 K for the subsequent two passes. The resultant microstructure and mechanical properties were determined. Workability of the alloy at 423 K (150 °C) was determined using upsetting experiments on cylindrical specimens machined from the annealed and ECAPed samples. Workability limit diagrams have been constructed for the various processed conditions. The workability data generated were also analyzed using five different workability criteria (also referred to as ductile fracture models) and the material constants for these five models were evaluated. Specimens processed by two passes through route C (pass 2C) exhibits better workability compared to other passes since the workability limit line after this pass shows maximum safe working area and lies above the other workability lines. Among the five different workability criteria investigated, the Freudenthal workability criterion is more suitable for prediction of failure in this alloy.

  10. Flow behaviour of magnesium alloy AZ31B processed by equal-channel angular pressing

    International Nuclear Information System (INIS)

    Arun, M S; Chakkingal, U

    2014-01-01

    Magnesium alloys are characterised by their low density, high specific strength and stiffness. But, the potential application of Mg is limited by its low room-temperature ductility and formability. Formability can be improved by developing an ultrafine grained (UFG) structure. Equal channel angular pressing (ECAP) is a well known process that can be used to develop an ultrafine grained microstructure. The aim of this study was to investigate the flow behaviour of AZ31B magnesium alloy after ECAP. The specimen was subjected to three passes of ECAP with a die angle of 120° using processing route Bc. The processing temperature was 523 K for the first pass and 423 K for the subsequent two passes. The microstructure characterisation was done. Compression tests of ECAPed and annealed specimens were carried out at strain rates of 0.01 – 1s −1 and deformation temperatures of 200 – 300°C using computer servo-controlled Gleeble-3800 system. The value of activation energy Q and the empirical materials constants of A and n were determined. The equations relating flow stress and Zener-Hollomon parameter were proposed. In the case annealed AZ31, the activation energy was determined to be 154 kJ/mol, which was slightly higher than the activation energy of 144 kJ/mol for ECAPed AZ31

  11. Flow behaviour of magnesium alloy AZ31B processed by equal-channel angular pressing

    Science.gov (United States)

    Arun, M. S.; Chakkingal, U.

    2014-08-01

    Magnesium alloys are characterised by their low density, high specific strength and stiffness. But, the potential application of Mg is limited by its low room-temperature ductility & formability. Formability can be improved by developing an ultrafine grained (UFG) structure. Equal channel angular pressing (ECAP) is a well known process that can be used to develop an ultrafine grained microstructure. The aim of this study was to investigate the flow behaviour of AZ31B magnesium alloy after ECAP. The specimen was subjected to three passes of ECAP with a die angle of 120° using processing route Bc. The processing temperature was 523 K for the first pass and 423 K for the subsequent two passes. The microstructure characterisation was done. Compression tests of ECAPed and annealed specimens were carried out at strain rates of 0.01 - 1s-1 and deformation temperatures of 200 - 300°C using computer servo-controlled Gleeble-3800 system. The value of activation energy Q and the empirical materials constants of A and n were determined. The equations relating flow stress and Zener-Hollomon parameter were proposed. In the case annealed AZ31, the activation energy was determined to be 154 kJ/mol, which was slightly higher than the activation energy of 144 kJ/mol for ECAPed AZ31.

  12. Use of a high temperature hydrostatic extrusion technique for powders strengthening

    International Nuclear Information System (INIS)

    Decours, J.; Gavinet, J.; Weisz, M.

    1975-01-01

    A conventional 575 tonnes extrusion press has been modified by a device permitting the extrusion process by hydrostatic pression through a leakless mechanical set (13,000 bars maximum), from room temperature to 1,200 deg C. This new device allows: the high temperature hydrostatic extrusion for strengthening of powders, the isostatic compression of powders. Examples of realisations obtained by this process are described, including the influence of different parameters: pressure, temperature, extrusion ratio and for different materials: pure metals (iron, nickel, niobium, etc...) and alloys (stainless steel, molybdenum, niobium nickel alloys, etc...). Then, the advantages of the process are emphasized [fr

  13. Embedded Multimaterial Extrusion Bioprinting

    NARCIS (Netherlands)

    Rocca, Marco; Fragasso, Alessio; Liu, Wanjun; Heinrich, Marcel A.; Zhang, Yu Shrike

    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

  14. Fatigue properties of ultra-fine grain Cu–Cr alloy processed by equal-channel angular pressing

    International Nuclear Information System (INIS)

    Wang, Q.J.; Du, Z.Z.; Luo, L.; Wang, W.

    2012-01-01

    Highlights: ► The UFG Cu–Cr alloys processed by ECAP possess high strength and sufficient ductility. ► The ECAPed sample with UFG under strain controlled fatigue exhibited cyclic softening and lower fatigue limit compared to the unECAPed one. ► That cyclic softening of UFG Cu–Cr alloy is associated with some dislocation annihilation and the substructure recovery. ► Shear bands, microcracks and final fracture of UFG Cu–Cr fatigue samples occur predominantly along the shear plane corresponding to the last ECAP. - Abstract: A precipitation-hardening copper based alloy (Cu–0.6 wt.% Cr) was selected and the ultra-fine grain (UFG) microstructure was obtained by equal channel angular pressing (ECAP). The alloys tensile behaviors and fatigue properties were investigated experimentally, the results indicated that the Cu–Cr alloy processed by ECAP possessed high strength and sufficient ductility and the 12-passes ECAPed sample with UFG under strain controlled fatigue exhibited cyclic softening and lower fatigue limit compared to the unECAPed one. Moreover, the shear bands on the surface of cycled samples were also studied by scanning electron microscopy, the results showed that the oriented distribution of defects along the shear plane in the last ECAP processing was one of the major mechanisms of SBs formation.

  15. Dependence of equilibrium properties of channeled particles on transverse quasi temperature

    International Nuclear Information System (INIS)

    Kashlev, Yu.A.

    2006-01-01

    Quasi-equilibrium and kinetic characteristics of channeled particles are investigated by methods of nonequilibrium statistical thermodynamics. The equilibrium equation of the transverse energy of fast particles and the equilibrium equation of the transverse momentum of particles are derived. It is shown that equilibrium equations solution permits to obtain the expression for the transverse quasi-temperature of the channeled particle subsystem. The quasi-equilibrium angular distribution of particles after transmission through a thin monocrystal and the angular distribution at backscattering are studied. The evaluated data of the transverse quasi-temperature are presented for the case of iodine ion channeling through silver crystals [ru

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

    Science.gov (United States)

    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.

  17. A convergent-beam electron diffraction study of strain homogeneity in severely strained aluminum processed by equal-channel angular pressing

    Energy Technology Data Exchange (ETDEWEB)

    Alhajeri, Saleh N. [Materials Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom); Department of Manufacturing Engineering, College of Technological Studies, PAAET, PO Box 42325, Shuwaikh 70654 (Kuwait); Fox, Alan G. [Materials Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom); Mechanical Engineering Department, Asian University, 89 Moo 12, Highway 331, Banglamung, Chon Buri 20260 (Thailand); Langdon, Terence G., E-mail: langdon@usc.edu [Materials Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom); Departments of Aerospace and Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States)

    2011-11-15

    Aluminum of commercial purity was processed by equal-channel angular pressing (ECAP) through two, four and eight passes at room temperature. A series of [1 1 4] convergent-beam electron diffraction (CBED) zone axis patterns were obtained using an electron probe with a diameter of 20 nm. Observations were recorded both immediately adjacent to the grain boundaries and in the grain interiors. Symmetry breaking of the higher-order Laue zone (HOLZ) lines was observed adjacent to the boundaries after two and four passes but not in the grain interiors. Pattern simulation of the CBED patterns taken from the two- and four-pass samples adjacent to the boundaries revealed a homogeneous strain with compressive and shear components. The presence of these homogeneous strains demonstrates that the internal stresses associated with the deformation of aluminum at room temperature are localized in the close vicinity, to within {approx}20 nm, of the grain boundaries.

  18. Study of CP Symmetry Violation in the Charmonium-K*(892) Channel By a Complete Time Dependent Angular Analysis (BaBar Experiment)

    Energy Technology Data Exchange (ETDEWEB)

    T' Jampens, Stephane; /Orsay

    2006-09-18

    This thesis presents the full-angular time-dependent analysis of the vector-vector channel B{sub d}{sup 0} {yields} J/{psi}(K{sub S}{sup 0}{pi}{sup 0})*{sup 0}. After a review of the CP violation in the B meson system, the phenomenology of the charmonium-K*(892) channels is exposed. The method for the measurement of the transversity amplitudes of the B {yields} J/{psi}K*(892), based on a pseudo-likelihood method, is then exposed. The results from a 81.9 fb{sup -1} of collected data by the BABAR detector at the {Upsilon}(4S) resonance peak are |A{sub 0}|{sup 2} = 0.565 {+-} 0.011 {+-} 0.004, |A{sub {parallel}}|{sup 2} = 0.206 {+-} 0.016 {+-} 0.007, |A{sub {perpendicular}}|{sup 2} = 0.228 {+-} 0.016 {+-} 0.007, {delta}{sub {parallel}} = -2.766 {+-} 0.105 {+-} 0.040 and {delta}{sub {perpendicular}} = 2.935 {+-} 0.067 {+-} 0.040. Note that ({delta}{sub {parallel}}, {delta}{sub {perpendicular}}) {yields} (-{delta}{sub {parallel}}, {pi} - {delta}{sub {perpendicular}}) is also a solution. The strong phases {delta}{sub {parallel}} and {delta}{sub {perpendicular}} are at {approx}> 3{sigma} from {+-}{pi}, signing the presence of final state interactions and the breakdown of the factorization hypothesis. The forward-backward analysis of the K{pi} mass spectrum revealed the presence of a coherent S-wave interfering with the K*(892). It is the first evidence of this wave in the K{pi} system coming from a B meson. The particularity of the B{sub d}{sup 0} {yields} J/{psi}(K{sub S}{sup 0}{pi}{sup 0})*{sup 0} channel is to have a time-dependent but also an angular distribution which allows to measure sin 2{beta} but also cos2{beta}. The results from an unbinned maximum likelihood fit are sin 2{beta} = -0.10 {+-} 0.57 {+-} 0.14 and cos 2{beta} = 3.32{sub -0.96}{sup +0.76} {+-} 0.27 with the transversity amplitudes fixed to the values given above. The other solution for the strong phases flips the sign of cos 2{beta}. Theoretical considerations based on the s-quark helicity

  19. CHARACTERIZATION OF NEW TOOL STEEL FOR ALUMINUM EXTRUSION DIES

    Directory of Open Access Journals (Sweden)

    José Britti Bacalhau

    2014-06-01

    Full Text Available Aluminum extrusion dies are an important segment of application on industrial tools steels, which are manufactured in steels based on AISI H13 steel. The main properties of steels applied to extrusion dies are: wear resistance, impact resistance and tempering resistance. The present work discusses the characteristics of a newly developed hot work steel to be used on aluminum extrusion dies. The effects of Cr and Mo contents with respect to tempering resistance and the Al addition on the nitriding response have been evaluated. From forged steel bars, Charpy impact test and characterization via EPMA have been conducted. The proposed contents of Cr, Mo, and Al have attributed to the new VEX grade a much better tempering resistance than H13, as well as a deeper and harder nitrided layer. Due to the unique characteristics, this new steel provides an interesting alternative to the aluminum extrusion companies to increase their competitiveness.

  20. Channeling ion implantation through palladium films

    International Nuclear Information System (INIS)

    Ishiwara, H.; Furukawa, S.

    1975-01-01

    The possibility of channeling ion implantation into semiconductors through polycrystalline metallic layers is studied. Minimum values and standard deviations of channeling angular yield in polycrystalline Pd 2 Si layers formed on Si have been measured by protons and 4 He, and 14 N ion backscattering and channeling measurements. Depth distributions of the spread of crystallite orientations and scattering centers such as lattice defects have been separately derived by using the above two quantities. It has been concluded that the channeling-ion-implantation technique will become a practical one by using the parallel scanning system

  1. Finite element analysis of the combined fine blanking and extrusion process

    Science.gov (United States)

    Zheng, Peng-Fei

    The combined fine blanking and extrusion process is such a metal forming process that fine blanking and forward extrusion are carried out on sheet metal material at the same time. There are two typical characteristics in this process, one is the fine blanking whose deformation mechanism is different from conventional blanking; the other is the sheet metal extrusion, which is different from the conventional extrusion. Even though fine blanking has been used in industry for many years, only limited literature can be found which deals with the theoretical analysis of it. On the other hand, no publications on the theoretical analysis of the sheet metal extrusion have been found. Intensive work should be carried out to reveal the mechanism of both fine blanking process and sheet metal extrusion process, and further the combined fine blanking and extrusion process. The scope of this thesis is to study the mechanics of fine blanking, sheet metal extrusion, and combined fine blanking and extrusion process one by one with the rigid-plastic finite element method. All of above processes are typical unsteady ones, especially the fine blanking process in which extremely severe and localized deformation occurs. Therefore, commercial programs can not be used to solve these problems up till now. Owing to this reason, a rigid-plastic finite element program was developed for simulating these processes where remeshing and mesh tracing techniques as well as the golden section method were adopted according to the characteristics of these processes in this thesis. Moreover, a permissible kinematic velocity field was adopted as the initial velocity field for simulating extrusion process successfully. Results from the simulation included the distorted mesh, the field of material flow, the stress and the strain distributions at various moments of deformation. Results under different deformation conditions such as different blanking clearances, different diameters of the extrusion punch and

  2. IMPORTANT DEGRADATIONS IN POLYETHYLENE TERAPHTALATE EXTRUSION PROCESS

    Directory of Open Access Journals (Sweden)

    Şule ALTUN

    2003-01-01

    Full Text Available Polyethylene terephthalate (PET is one of the most used thermo-plastic polymers. The total consumption of PET has been about 30 million tons in the year 2000. Polyester fibers constitute about 60 % of total synthetic fibers consumption. During extrusion, PET polymer is faced to thermal, thermo-oxidative and hydrolytic degradation, which result in severe reduction in its molecular weight, thereby adversely affecting its subsequent melt processability. Therefore, it is essential to understand degradation processes of PET during melt extrusion.

  3. A new constitutive analysis of hexagonal close-packed metal in equal channel angular pressing by crystal plasticity finite element method

    Science.gov (United States)

    Li, Hejie; Öchsner, Andreas; Yarlagadda, Prasad K. D. V.; Xiao, Yin; Furushima, Tsuyoshi; Wei, Dongbin; Jiang, Zhengyi; Manabe, Ken-ichi

    2018-01-01

    Most of hexagonal close-packed (HCP) metals are lightweight metals. With the increasing application of light metal products, the production of light metal is increasingly attracting the attentions of researchers worldwide. To obtain a better understanding of the deformation mechanism of HCP metals (especially for Mg and its alloys), a new constitutive analysis was carried out based on previous research. In this study, combining the theories of strain gradient and continuum mechanics, the equal channel angular pressing process is analyzed and a HCP crystal plasticity constitutive model is developed especially for Mg and its alloys. The influence of elevated temperature on the deformation mechanism of the Mg alloy (slip and twin) is novelly introduced into a crystal plasticity constitutive model. The solution for the new developed constitutive model is established on the basis of the Lagrangian iterations and Newton Raphson simplification.

  4. Extrusion: An environmentally friendly process for PEMFC membrane elaboration

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, J.-Y.; Iojoiu, C.; Marechal, M. [LEPMI, UMR 5631 CNRS-INPG-UJF, ENSEEG, BP 75, F-38402, Saint Martin d' Heres (France); Chabert, F.; El Kissi, N. [Rheologie, UMR 5520 CNRS-INPG-UJF, ENSHMG, BP 53, F-38041, Grenoble (France); Salomon, J.; Mercier, R. [LMOPS UMR CNRS 5041, BP 24, F-69390 Vernaison (France); Piffard, Y. [CNRS Universite de Nantes, Institut des Materiaux Jean Rouxel, UMR 6502, BP 32229, F-44322, Nantes Cedex 3 (France); Galiano, H. [CEA, Le Ripault Research Center, BP 16, F-37260, Monts (France)

    2007-12-31

    The paper deals with the use of extrusion to process PEMFC filled and unfilled membranes. Several routes including the sulfonation of filled and unfilled extruded membranes and the extrusion of filled and unfilled ionomers are reported. Thanks to the use of selected water-soluble aid process plasticizers, acid and alkaline forms of sulfonated polyethersulfone were, for the first time, successfully extruded. The extrusion process did not lead to any degradation of the ionomer performances. Decreasing the membrane cost while using environmentally friendly elaboration conditions, it should be helpful to an industrial production. In addition, avoiding filler sedimentation it should allow homogeneous composite membranes to be obtained. (author)

  5. Towards Extrusion of Ionomers to Process Fuel Cell Membranes

    Directory of Open Access Journals (Sweden)

    Jean-Yves Sanchez

    2011-07-01

    Full Text Available While Proton Exchange Membrane Fuel Cell (PEMFC membranes are currently prepared by film casting, this paper demonstrates the feasibility of extrusion, a solvent-free alternative process. Thanks to water-soluble process-aid plasticizers, duly selected, it was possible to extrude acidic and alkaline polysulfone ionomers. Additionally, the feasibility to extrude composites was demonstrated. The impact of the plasticizers on the melt viscosity was investigated. Following the extrusion, the plasticizers were fully removed in water. The extrusion was found to impact neither on the ionomer chains, nor on the performances of the membrane. This environmentally friendly process was successfully validated for a variety of high performance ionomers.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  8. X-ray radiation channeling in micro-channel plates: Spectroscopy with a synchrotron radiation beam

    International Nuclear Information System (INIS)

    Mazuritskiy, M.I.; Dabagov, S.B.; Marcelli, A.; Dziedzic-Kocurek, K.; Lerer, A.M.

    2015-01-01

    We present here the angular distribution of the radiation propagated inside MultiChannel Plates with micro-channels of ∼3 μm diameter. The spectra collected at the exit of the channels present a complex distribution with contributions that can be assigned to the fluorescence radiation, originated from the excitation of the micro-channel walls. For radiation above the absorption edge, when the monochromatic energy in the region of the Si L-edge hits the micro-channel walls with a grazing angle θ ⩾ 5°, or at the O K-edge when θ ⩾ 2° a fluorescence radiation is detected. Additional information associated to the fine structures of the XANES spectra detected at the exit of MCPs are also presented and discussed

  9. Evolution of orbital angular momentum entangled bi-photon, propagating through a turbulent atmosphere

    CSIR Research Space (South Africa)

    Roux, FS

    2011-01-01

    Full Text Available Orbital angular momentum (OAM) entangled bi-photons are a resource for the higher dimensional implementation of quantum cryptography, which allows secure communication over various channels. In the case where free-space is used as communication...

  10. Momentum distribution at great depths when electron axial channeling

    International Nuclear Information System (INIS)

    Khokonov, M.Kh.; Tuguz, F.K.

    1989-01-01

    The electron distribution in momenta during axial channeling in thick monocrystals in great depths is estimated. The estimate was carried out with respect to the fact that due to diffusion the angular momentum of the electron can change only in a limited region of phase space and that multiple scattering only takes place on thermal oscillations of nuclei of the crystal lattice. It is shown that in thick monocrystals the distribution in momenta can be considered uniform on the greater part of the way of channeled electrons which can simplity the qualitative consideration of spectral-angular characteristics forming during this radiation

  11. Magnetic Field Generation and Electron Acceleration in Relativistic Laser Channel

    International Nuclear Information System (INIS)

    Kostyukov, I.Yu.; Shvets, G.; Fisch, N.J.; Rax, J.M.

    2001-01-01

    The interaction between energetic electrons and a circularly polarized laser pulse inside an ion channel is studied. Laser radiation can be resonantly absorbed by electrons executing betatron oscillations in the ion channel and absorbing angular momentum from the laser. The absorbed angular momentum manifests itself as a strong axial magnetic field (inverse Faraday effect). The magnitude of this magnetic field is calculated and related to the amount of the absorbed energy. Absorbed energy and generated magnetic field are estimated for the small and large energy gain regimes. Qualitative comparisons with recent experiments are also made

  12. Assembling filamentous phage occlude pIV channels.

    Science.gov (United States)

    Marciano, D K; Russel, M; Simon, S M

    2001-07-31

    Filamentous phage f1 is exported from its Escherichia coli host without killing the bacterial cell. Phage-encoded protein pIV, which is required for phage assembly and secretion, forms large highly conductive channels in the outer membrane of E. coli. It has been proposed that the phage are extruded across the bacterial outer membrane through pIV channels. To test this prediction, we developed an in vivo assay by using a mutant pIV that functions in phage export but whose channel opens in the absence of phage extrusion. In E. coli lacking its native maltooligosacharride transporter LamB, this pIV variant allowed oligosaccharide transport across the outer membrane. This entry of oligosaccharide was decreased by phage production and still further decreased by production of phage that cannot be released from the cell surface. Thus, exiting phage block the pIV-dependent entry of oligosaccharide, suggesting that phage occupy the lumen of pIV channels. This study provides the first evidence, to our knowledge, for viral exit through a large aqueous channel.

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

    Science.gov (United States)

    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.

  14. Angular distributions of evaporation residues from near-barrier fusion of 32,36S on a ≅100 nuclei

    International Nuclear Information System (INIS)

    Borges, A.M.

    1986-01-01

    The angular distributions of evaporation residues from near-barrier fusion of 32,36 S ions with 92,94,96,98,100 Mo, 100,101,102,104 Ru, 103 Rh, and 104,105,106,108,110 Pd were measured in the range of 3 to 11 degrees in the laboratory system. The relative yield of the four most abundant exit evaporation channels has been extracted for all target-projectile combination at two bombarding energies, by fitting the angular distributions expected for each channel as obtained from the Monte-Carlo program TRANMI to the measured angular distribution of the evaporation residues. The total detection efficiency for the Munich-RF-Recoil Spectrometer was obtained from the relative yields, taking into account the effect due to multiple scattering, and compared with that obtained previously from the recoil velocity distributions. (orig./HSI) [de

  15. X-ray diffraction analysis of aluminium containing Al8Fe2Si processed by equal channel angular pressing

    International Nuclear Information System (INIS)

    Korchef, Atef; Champion, Yannick; Njah, Nabil

    2007-01-01

    A 99.1% aluminium with initial grain size of ∼85 μm was deformed by equal channel angular (ECA) pressing. The sample undergoes an effective strain of 1.07 N by N passes through the die. The material contains a low volume fraction of Al 8 Fe 2 Si precipitates located essentially at the grain boundaries. The analysis of the X-ray diffraction peaks showed a significant broadening, which was related to grain refinement and lattice distortions. The crystallite size, calculated using the Halder-Wagner method, reached 225 nm after two passes and did not subsequently change. A decrease of the lattice parameter was also observed after ECA pressing. This is due to a partial dissolution of the precipitates. The microstructure was stable up an annealing of 200 deg. C due to the precipitates which delay the diffusion process. The annealing of the ECA pressed samples up to 400 deg. C leads to a decrease in the X-ray diffraction peaks broadening and an increase of the lattice parameter. This is due to grain growth

  16. Die design and process optimization of plastic gear extrusion

    Science.gov (United States)

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

    2018-01-01

    The flow velocity of the melt in the extruder was simulated by using software Polyflow, and the size of the die channel with the best flow uniformity was obtained. The die profile shape is obtained by reverse design. The length of the shaping section is determined by Ansys transient thermal analysis. According to the simulation results, the design and manufacture of extrusion die of plastic gear and vacuum cooling setting were obtained. The influence of the five process parameters on the precision of the plastic gear were studied by the single factor analysis method, such as the die temperature T, the screw speed R, the die spacing S, the vacuum degree M and the hauling speed V. The optimal combination of process parameters was obtained by using the neural network particle swarm optimization algorithm(T = 197.05 °C, R = 9.04rpm, S = 67mm, M = -0.0194MPa). The tooth profile deviation of the extruded plastic gear can reach 9 level of accuracy.

  17. An Orbital Angular Momentum (OAM) Mode Reconfigurable Antenna for Channel Capacity Improvement and Digital Data Encoding.

    Science.gov (United States)

    Liu, Baiyang; Lin, Guoying; Cui, Yuehui; Li, RongLin

    2017-08-29

    For purpose of utilizing orbital angular momentum (OAM) mode diversity, multiple OAM beams should be generated preferably by a single antenna. In this paper, an OAM mode reconfigurable antenna is proposed. Different from the existed OAM antennas with multiple ports for multiple OAM modes transmitting, the proposed antenna with only a single port, but it can be used to transmit mode 1 or mode -1 OAM beams arbitrary by controlling the PIN diodes on the feeding network through a programmable microcontroller which control by a remote controller. Simulation and measurement results such as return loss, near-field and far-field radiation patterns of two operating states for mode 1 and mode -1, and OAM mode orthogonality are given. The proposed antenna can serve as a candidate for utilizing OAM diversity, namely phase diversity to increase channel capacity at 2.4 GHz. Moreover, an OAM-mode based encoding method is experimentally carried out by the proposed OAM mode reconfigurable antenna, the digital data are encoded and decoded by different OAM modes. At the transmitter, the proposed OAM mode reconfigurable antenna is used to encode the digital data, data symbol 0 and 1 are mapped to OAM mode 1 and mode -1, respectively. At the receiver, the data symbols are decoded by phase gradient method.

  18. Instant blend from cassava derivatives produced by extrusion

    OpenAIRE

    Trombini, Fernanda Rossi Moretti; Mischan, Martha Maria; Leonel, Magali

    2016-01-01

    ABSTRACT: The current research aimed to evaluate the effects of extrusion parameters on the physical characteristics of extruded blends of cassava leaf flour and starch. A factorial central composite design with four independent variables and the response surface methodology were used to evaluate the results of color parameters (L*, a*, b*), water absorption index, water solubility index and paste properties, according to the variations in the leaf flour percentage (1.5 to 7.5%), extrusion te...

  19. Rapid Continuous Multimaterial Extrusion Bioprinting

    NARCIS (Netherlands)

    Liu, Wanjun; Zhang, Yu Shrike; Heinrich, Marcel A.; De Ferrari, F; Jang, HL; Bakht, SM; Alvarez, MM; Yang, J; Li, YC; Trujillo-de Stantiago, G; Miri, AK; Zhu, K; Khoshakhlagh, P; Prakash, G; Cheng, H; Guan, X; Zhong, Z; Ju, J; Zhu, GH; Jin, X; Ryon Shin, Su; Dokmeci, M.R.; Khademhosseini, Ali

    The development of a multimaterial extrusion bioprinting platform is reported. This platform is capable of depositing multiple coded bioinks in a continuous manner with fast and smooth switching among different reservoirs for rapid fabrication of complex constructs, through digitally controlled

  20. Embedded Multimaterial Extrusion Bioprinting.

    Science.gov (United States)

    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.

  1. Axial ion channeling patterns from ultra-thin silicon membranes

    International Nuclear Information System (INIS)

    Motapothula, M.; Dang, Z.Y.; Venkatesan, T.; Breese, M.B.H.; Rana, M.A.; Osman, A.

    2012-01-01

    We present channeling patterns produced by MeV protons transmitted through 55 nm thick [0 0 1] silicon membranes showing the early evolution of the axially channeled beam angular distribution for small tilts away from the [0 0 1], [0 1 1] and [1 1 1] axes. Instead of a ring-like “doughnut” distribution previously observed at small tilts to major axes in thicker membranes, geometric shapes such as squares and hexagons are observed along different axes in ultra-thin membranes. The different shapes arise because of the highly non-equilibrium transverse momentum distribution of the channeled beam during its initial propagation in the crystal and the reduced multiple scattering which allows the fine angular structure to be resolved. We describe a simple geometric construction of the intersecting planar channels at an axis to gain insight into the origin of the geometric shapes observed in such patterns and how they evolve into the ‘doughnut’ distributions in thicker crystals.

  2. Angular momentum branching ratios for electron-induced ionization: Atomic and model calculations

    International Nuclear Information System (INIS)

    Mehl, M.J.; Einstein, T.L.

    1987-01-01

    We present calculations of the matrix elements for electron-induced ionization of core electrons of atoms. We use both self-consistent atomic potentials for accuracy and model potentials to gain physical insight. We pay particular attention to the angular momentum distribution of the two final-state electrons, especially when one of them lies near what would be the Fermi energy in a solid (i.e., as in an absorption fine-structure experiment). For nodeless core wave functions, in the dominant channel both final-state electrons have angular momentum one greater than that of the initial core state. For sufficiently deeply bound states, this first approximate selection rule holds until the incident electron energy exceeds the ionization threshold by at least 500 eV, i.e., over the experimentally relevant range. It is also possible to determine the angular momentum distribution of the final-state electron. The EXAFS-like electron tends to have angular momentum one greater than that of the initial core state, even in some cases where the first approximate selection rule does not hold. (EXAFS is extended x-ray-absorption fine structure.) The strongest trend is that the dipole component in a partial-wave expansion of the Coulomb interaction dominates the matrix element. In these studies, careful treatment of not just the core state but also the unbound states is crucial; we show that the conventional orthogonalized plane-wave approximation is inadequate, giving incorrect ordering of the channels. For model potentials with an adjustable screening length, low-lying bound resonances are found to play an important role

  3. REFINEMENT OF THE REVERSE EXTRUSION TEST TO DETERMINE THE TWO CONSISTENCY LIMITS

    Directory of Open Access Journals (Sweden)

    Kamil KAYABALI

    2015-11-01

    Full Text Available Liquid limit (LL and plastic limit (PL are the two most commonly used index proper- ties of fine-grained soils. They have been used in not only classification of soils but also in correlation with certain engineering properties. Therefore, they have been subjected to numerous researches since they were first introduced by Atterberg in 1911. While their me- chanisms were well defined in many codes and they have been in use for decades, criticisms often arose pertinent to the uncertainties inherent to them. Incredible amount of effort has been exerted to invent more rational testing methods in place of both the Casagrande’s cup and bead rolling methods. Part of those efforts has been on devicing a single tool to measure the two relative index properties together. Recently, the reverse extrusion test was brought into the use of geotechnical engineers. It was shown that this tool has a potential of measu- ring LL, PL, and even the shrinkage limit (SL. The aim of this investigation is to reassess the ability of the reverse extrusion test to determine LL and PL with further refinement. In this regard 70 fine-grained soils covering a large range of plasticity were employed. Fall-cone method and rolling-device method were employed to determine LL and PL, res- pectively. The reverse extrusion tests were carried out at least five different water contents per soil sample. Extrusion pressures were plotted against water content and a curve fitting was applied to data pairs, from which the y-intercept (the coefficient a and the slope (the coefficieent b of the curve were determined. Those reverse extrusion coefficients were utilized to determine the representative extrusion pressures corresponding to LL and PL, as was done by the earlier researchers; however, the degree of success for the prediction of LL and PL using the representative extrusion pressures was not encouraging. Different from the previously proposed approaches, the reverse extrusion

  4. Angular analysis and CP violation studies in B decays at CMS

    CERN Document Server

    Chen, Kai-Feng

    2014-01-01

    Angular distributions of the decay $B^0 \\to K^{*0} \\mu^+\\mu^-$ are a clean probe of physics beyond the standard model. In particular the forward-backward asymmetry and other variables which can be determined as a function of $q^2$, provide fruitful information from a single decay channel. An angular and proper decay time analysis is applied to the $B_s \\to J/\\psi \\phi$ decays. The $B_s$ signal candidates are reconstructed and used to extract the mixing phase $\\phi_s$. The theoretical prediction of the $\\phi_s$ angle is particularly robust, thus any deviation from the prediction can be a smoking gun signal of new physics.

  5. 75 FR 69403 - Aluminum Extrusions From the People's Republic of China: Notice of Preliminary Determination of...

    Science.gov (United States)

    2010-11-12

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-967] Aluminum Extrusions From the... Commerce (``Department'') preliminarily determines that aluminum extrusions from the People's Republic of... of aluminum extrusions from the PRC filed in proper form by the Aluminum Extrusions Fair Trade...

  6. Microstructure evolution of pure copper during a single pass of simple shear extrusion (SSE): role of shear reversal

    Energy Technology Data Exchange (ETDEWEB)

    Bagherpour, E., E-mail: e.bagherpour@semnan.ac.ir [Faculty of Metallurgical and Materials Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Department of Mechanical Engineering, Doshisha University, Kyotanabe, Kyoto 610–0394 (Japan); Qods, F., E-mail: qods@semnan.ac.ir [Faculty of Metallurgical and Materials Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Ebrahimi, R., E-mail: ebrahimy@shirazu.ac.ir [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Miyamoto, H., E-mail: hmiyamot@mail.doshisha.ac.jp [Department of Mechanical Engineering, Doshisha University, Kyotanabe, Kyoto 610–0394 (Japan)

    2016-06-01

    In the present paper the role of shear reversal on microstructure, texture and mechanical properties of pure copper during a single pass of the simple shear extrusion (SSE) process was investigated. For SSE processing an appropriate die with a linear die profile was designed and constructed, which imposes forward shear in the first half and reverse shear in the second half channels. Electron back-scattering diffraction (EBSD), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) were used to evaluate the microstructure of the deformed samples. The geometrical nature of this process imposes a distribution of strain results in the inhomogeneous microstructure and the hardness throughout the plane perpendicular to the extrusion direction. Strain reversal during the process results in a slight reduction in dislocation density, the hardness and mean disorientation angle of the samples, and an increase in the grain size. After a complete pass of SSE, dislocation density decreased by ~14% if compared to the middle of the process. This suggests that the dislocation annihilation occurred by the reversal of the shear strain. The simple shear textures were formed gradually and the strongest simple shear textures were observed on the middle of the SSE channel. The degree of the simple shear textures decreases with the distance from the middle plane where the shear is reversed, but the simple shear textures are still the major components after exit of the channel. Hardness variation was modeled by contributions from dislocation strengthening and grain boundary strengthening, where dislocation density is approximated by the misorientation angle of LAGBs which are regarded as dislocation cell boundaries. As a result, the hardness can be predicted successfully by the microstructural features, i.e. the low-angle boundaries, the mean misorientation angle and the fraction of high-angle grain boundaries.

  7. Isotropic gates and large gamma detector arrays versus angular distributions

    International Nuclear Information System (INIS)

    Iacob, V.E.; Duchene, G.

    1997-01-01

    Angular information extracted from in-beam γ ray measurements are of great importance for γ ray multipolarity and nuclear spin assignments. In our days large Ge detector arrays became available allowing the measurements of extremely weak γ rays in almost 4π sr solid angle (e.g., EUROGAM detector array). Given the high detector efficiency it is common for the mean suppressed coincidence multiplicity to reach values as high as 4 to 6. Thus, it is possible to gate on particular γ rays in order to enhance the relative statistics of a definite reaction channel and/or a definite decaying path in the level scheme of the selected residual nucleus. As compared to angular correlations, the conditioned angular distribution spectra exhibit larger statistics because in the latter the gate-setting γ ray may be observed by all the detectors in the array, relaxing somehow the geometrical restrictions of the angular correlations. Since the in-beam γ ray emission is anisotropic one could inquire that gate setting as mentioned above, based on anisotropic γ ray which would perturb the angular distributions in the unfolded events. As our work proved, there is no reason to worry about this if the energy gate runs over the whole solid angle in an ideal 4π sr detector, i.e., if the gate is isotropic. In real quasi 4π sr detector arrays the corresponding quasi isotropic gate preserves the angular properties of the unfolded data, too. However extraction of precise angular distribution coefficient especially a 4 , requires the consideration of the deviation of the quasi isotropic gate relative to the (ideal) isotropic gate

  8. 75 FR 57441 - Aluminum Extrusions From the People's Republic of China: Alignment of Final Countervailing Duty...

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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.

  10. 76 FR 30650 - Aluminum Extrusions from the People's Republic of China: Antidumping Duty Order

    Science.gov (United States)

    2011-05-26

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-967] Aluminum Extrusions from the...''), the Department is issuing an antidumping duty order on aluminum extrusions from the People's Republic... of material injury by reason of imports of certain aluminum extrusions from the PRC, and its negative...

  11. Effects of pressing temperature and initial microstructure on the equal channel angular pressing of Ti-6Al-4V alloy

    International Nuclear Information System (INIS)

    Ko, Y.G.; Lee, Y.H.; Jung, W.S.; Shin, D.H.; Lee, C.S.

    2003-01-01

    The effects of pressing temperature and initial microstructure on the equal channel angular (ECA) pressing of Ti-6Al-4V alloy were investigated in this study. The ECA pressing was carried out isothermally with route C at 500 C, 600 C and 700 C for two typical microstructures, i.e., the Widmanstaetten microstructure and the equiaxed microstructure. The results showed that ECA pressing at 600 C and 700 C was successful without producing any noticeable segment at the specimen surfaces, while a large amount of surface segments were produced at 500 C. After 1 pass pressing at 600 C, the equiaxed microstructure showed more uniform material flow at the surface than the Widmanstaetten microstructure. However, this microstructural influence was diminished with increase of the number of the ECA pressing. A flow-localization parameter that quantifies the flow non-uniform tendency in case of flow softening materials was used to explain the different results in each microstructure. (orig.)

  12. Extrusion conditions affect chemical composition and in vitro digestion of select food ingredients.

    Science.gov (United States)

    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.

  13. Hot-melt extrusion of sugar-starch-pellets.

    Science.gov (United States)

    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.

  14. Influence of tools geometry and processing conditions on behavior of a difficult-to-work Al-Mg alloy during equal channel angular pressing

    Science.gov (United States)

    Comǎneci, Radu Ioachim; Nedelcu, Dumitru; Bujoreanu, Leandru Gheorghe

    2017-10-01

    Equal channel angular pressing (ECAP) is a well-established method for grain refinement in metallic materials by large shear plastic deformation, being the most promising and effective severe plastic deformation (SPD) technique. ECAP is a discontinuous process, so the billet removal implies a new development of the procedure: the new sample pushes out the previous sample. In resuming the process the head and the tail ends of the work piece which becomes strongly distorted and receiving different amount of strain have to be removed. Due to the path difference in material flow between upper and lower region of the outlet channel, a non-uniform strain and stress distribution across the width of the workpiece leaving the plastic deformation zone (PDZ) is achieved. A successful ECAP requires surpassing two obstacles: the necessary load level which directly affects tools and a favorable stress distribution so the material withstanding the accumulated strain of repeated deformation. Under back pressure (BP), materials have shown to be able to withstand more passes. As soon as the billet passes the PDZ along the bisector plane of the two channels, the compressive mean stress changes to tensile (leading to crack initiation), while in the presence of BP, a negative (compressive) stress is applied during the process. In this paper a comparative tridimensional finite element analysis (FEA) is performed to evaluate the behavior of a difficult-to-work Al-Mg alloy depending on tools geometry and process parameters. The results in terms of load level and strain distribution show the influence of the punch geometry and BP on the material behavior.

  15. Optimizing the equal channel angular pressing process (ECAP) operation parameters to produce bulk nanostructure materials

    International Nuclear Information System (INIS)

    Abushgair, K.

    2015-01-01

    In this work we were interested in doing simulation using finite elements analysis (FEA) to study the equal channel angular pressing process (ECAP), which is currently one of the most popular methods of severe plastic deformation Processes (SPD). for fabricating Ultra-Fine Grained (UFG) materials, because it allows very high strains to be imposed leading to extreme work hardening and microstructural refinement. The main object of this study is to establish the influence of main parameters which effect ECAP process which are magnitude of the die angle and the friction coefficient. The angle studied between (90-135°) degree, and magnitude of the friction coefficient μ between (0.12-0.6), and number of pass. The samples were made from aluminum alloy at room temperature with (15X 15) mm cross section and 150 mm length. The simulation result shows that normal elastic strain, shears elastic strain, and max. shear elastic strain increased, when changing the angle from 90° to 100°. and decrease between the angle 110° to 135°. Also the total deformation increased when we change die angle from 90° to 135°. By studding the friction effect on the die and sample we noted that increasing the friction coefficient from 0.12 to 0.6, normal elastic strain, and shear elastic strain increased and increasing the friction coefficient from 0.1 to 0.6 decrease the normal and shear stress

  16. FEM analysis of hollow hub forming in rolling extrusion process

    Directory of Open Access Journals (Sweden)

    J. Bartnicki

    2014-10-01

    Full Text Available In this paper are presented the results of numerical calculations of rolling extrusion process of a hollow hub. As the flanges manufacturing at both sides of the product is required, in the analyzed process of rolling extrusion, a rear bumper was implemented as additional tool limiting axial metal flow. Numerical calculations of the hub forming process were conducted basing on finite element method, applying software Deform3D and Simufact in conditions of three dimensional state of strain. The obtained satisfactory results show that it is possible to conduct the further research works of experimental character, with the application of a modernized aggregate for the rolling extrusion process PO-2.

  17. Comparative Analysis of the Effects of Severe Plastic Deformation and Thermomechanical Training on the Functional Stability of Ti50.5Ni24.5Pd25 High-Temperature Shape Memory Alloy

    Science.gov (United States)

    Atli, K. C.; Karaman, I.; Noebe, R. D.; Maier, H. J.

    2010-01-01

    We compare the effectiveness of a conventional thermomechanical training procedure and severe plastic deformation via equal channel angular extrusion to achieve improved functional stability in a Ti50.5Ni24.5Pd25 high-temperature shape memory alloy. Thermomechanical testing indicates that both methods result in enhanced shape memory characteristics, such as reduced irrecoverable strain and thermal hysteresis. The mechanisms responsible for the improvements are discussed in light of microstructural findings from transmission electron microscopy.

  18. High strength Al–Al2O3p composites: Optimization of extrusion parameters

    DEFF Research Database (Denmark)

    Luan, B.F.; Hansen, Niels; Godfrey, A.

    2011-01-01

    Composite aluminium alloys reinforced with Al2O3p particles have been produced by squeeze casting followed by hot extrusion and a precipitation hardening treatment. Good mechanical properties can be achieved, and in this paper we describe an optimization of the key processing parameters...... on an investigation of their mechanical properties and microstructure, as well as on the surface quality of the extruded samples. The evaluation shows that material with good strength, though with limited ductility, can be reliably obtained using a production route of squeeze casting, followed by hot extrusion....... The parameters investigated are the extrusion temperature, the extrusion rate and the extrusion ratio. The materials chosen are AA 2024 and AA 6061, each reinforced with 30vol.% Al2O3 particles of diameter typically in the range from 0.15 to 0.3μm. The extruded composites have been evaluated based...

  19. Factors affecting irrigant extrusion during root canal irrigation: a systematic review

    NARCIS (Netherlands)

    Boutsioukis, C.; Psimma, Z.; van der Sluis, L.W.M.

    2013-01-01

    The aim of the present study was to conduct a systematic review and critical analysis of published data on irrigant extrusion to identify factors causing, affecting or predisposing to irrigant extrusion during root canal irrigation of human mature permanent teeth. An electronic search was conducted

  20. A novel plastification agent for cemented carbides extrusion molding

    International Nuclear Information System (INIS)

    Ji-Cheng Zhou; Bai-Yun Huang

    2001-01-01

    A type of novel plastification agent for plasticizing powder extrusion molding of cemented carbides has been developed. By optimizing their formulation and fabrication method, the novel plastification agent, with excellent properties and uniform distribution characters, were manufactured. The thermal debinding mechanism has been studied, the extruding rheological characteristics and debinding behaviors have been investigated. Using the newly developed plastification agent, the cemented carbides extrusion rods, with diameter up to 25 mm, have been manufactured. (author)

  1. Professional AngularJS

    CERN Document Server

    Karpov, Valeri

    2015-01-01

    A comprehensive guide to AngularJS, Google's open-source client-side framework for app development. Most of the existing guides to AngularJS struggle to provide simple and understandable explanations for more advanced concepts. As a result, some developers who understand all the basic concepts of AngularJS struggle when it comes to building more complex real-world applications. Professional AngularJS provides a thorough understanding of AngularJS, covering everything from basic concepts, such as directives and data binding, to more advanced concepts like transclusion, build systems, and auto

  2. Extrusão de misturas de castanha do Brasil com mandioca Extrusion of Brazil nut and cassava flour mixtures

    Directory of Open Access Journals (Sweden)

    Maria Luzenira de Souza

    2008-06-01

    Full Text Available Considerando-se que a castanha do Brasil apresenta elevado potencial nutritivo, baixo consumo no Brasil, baixo valor agregado e é um produto orgânico, além da alta produtividade, do baixo custo da mandioca e da tecnologia de extrusão termoplástica apresentarem ampla aplicabilidade e vantagens, este trabalho teve como objetivo empregar estas três variáveis, para formular misturas com castanha do Brasil e farinha de mandioca e processá-las por extrusão, visando à obtenção de produtos extrusados ricos em proteína vegetal e prontos para o consumo. Foram utilizadas torta de amêndoa de castanha do Brasil semidesengordurada e farinha de mandioca para formulações das misturas para extrusão. Aplicou-se o delineamento fatorial completo composto central (2³, com 3 variáveis independentes e a metodologia de superfície de resposta foi usada para avaliar os resultados da composição centesimal e o valor calórico, frente às variações de castanha, umidade e temperatura. Os resultados indicam que as formulações com maiores quantidades de castanha apresentam quantidades de proteínas, lipídios e cinzas mais elevadas, já as formulações com menores teores de castanha apresentam maiores percentuais de carboidratos. Os coeficientes de regressão médios do modelo estatístico para as respostas são: umidade 7,40; carboidratos 51,09; proteínas 15,34; lipídios 11,77; fibra total 9,92 e kcal 371,65. Os ensaios com menores teores de castanha e maiores de farinha apresentam-se mais expandidos e de cor clara, enquanto que aqueles com maiores teores de castanha não se expandem e têm a cor acinzentada. Conclui-se que a adição de castanha semidesengordurada à farinha de mandioca pode ser submetida à extrusão, originando um produto extrusado fonte de proteína vegetal, pronto para o consumo e que pode atender à exigência de consumidores que não utilizam proteínas de origem animal.Considering that Brazil nut presents high nutritional

  3. Extrusion-cooking to improve the animal feed quality of broad beans

    NARCIS (Netherlands)

    Moscicki, L.; Wojcik, S.; Plaur, K.; Zuilichem, van D.J.

    1984-01-01

    Extrusion-cooking of broad beans with a single-screw extruder has been investigated. Attention was focused on process requirements as well as on the nutritional effects of extrusion-cooked broad beans in a chicken feed formulation. The optimal thermal process conditions required for a product of

  4. Relationship Between Preoperative Extrusion of the Medial Meniscus and Surgical Outcomes After Partial Meniscectomy.

    Science.gov (United States)

    Kim, Sung-Jae; Choi, Chong Hyuk; Chun, Yong-Min; Kim, Sung-Hwan; Lee, Su-Keon; Jang, Jinyoung; Jeong, Howon; Jung, Min

    2017-07-01

    No previous study has examined arthritic change after meniscectomy with regard to extrusion of the medial meniscus. (1) To determine the factors related to preoperative meniscal extrusion; (2) to investigate the relationship between medial meniscal extrusion and postoperative outcomes of partial meniscectomy, and to identify a cutoff point of meniscal extrusion that contributes to arthritic change after partial meniscectomy in nonosteoarthritic knees. Cohort study; Level of evidence, 3. A total of 208 patients who underwent partial meniscectomy of the medial meniscus between January 2000 and September 2006 were retrospectively reviewed. The extent of extrusion and severity of degeneration of the medial meniscus as shown on preoperative MRI were evaluated. The minimum follow-up duration was 7 years. Clinical function was assessed with the Lysholm knee scoring scale, the International Knee Documentation Committee (IKDC) subjective knee evaluation form, and the Tapper and Hoover grading system. Radiological evaluation was conducted by use of the IKDC radiographic assessment scale. Regression analysis was performed to identify factors affecting preoperative extrusion of the medial meniscus and factors influencing follow-up results after partial meniscectomy. Receiver operating characteristic curve was used to identify a cutoff point for the extent of meniscal extrusion that was associated with arthritic change. The mean ± SD preoperative Lysholm knee score was 65.0 ± 6.3 and the mean IKDC subjective score was 60.1 ± 7.5. The mean follow-up functional scores were 93.2 ± 5.1 ( P meniscus showed a tendency to increase as the extent of intrameniscal degeneration increased, and the medial meniscus was extruded more in patients with horizontal, horizontal flap, and complex tears. The preoperative extent of meniscal extrusion had a statistically significant correlation with follow-up Lysholm knee score (coefficient = -0.10, P = .002), IKDC subjective score (coefficient

  5. The Energetics and Physiological Impact of Cohesin Extrusion.

    Science.gov (United States)

    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.

  6. Angular momentum effects in subbarrier fusion

    International Nuclear Information System (INIS)

    Halbert, M.L.; Beene, J.R.; Hensley, D.C.; Honkanen, K.; Semkow, T.M.; Abenante, V.; Sarantites, D.G.; Li, Z.

    1987-01-01

    The authors discuss angular-momentum distributions σ l for the compound nucleus 164 Yb deduced from measurements of γ-ray multiplicity for all significant evaporation residues from fusion of 64 Ni and 100 Mo and 16 O + 148 Sm. At the lowest bombarding energies the σ l extend to higher l values than do predictions that include coupling of the principal inelastic channels, even if the coupling strengths are increased to match the experimental excitation function. Likewise, σ l from an energy-dependent real potential fitted to the excitation function fails to reproduce the experimental σ l distribution. No effects attributed to superdeformation were observed

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

    Science.gov (United States)

    2016-04-01

    specimens were mounted in an epoxy resin and prepared using conventional metallographic techniques. A final etching, using diluted picric acid, was...additional pass, the shearing texture is exaggerated and, unless reversed , an acicular texture in the material could result. The function of route C

  8. Metal extrusion using hydrostatic pressures; Le filage des metaux sous pression hydrostatique

    Energy Technology Data Exchange (ETDEWEB)

    Sauve, Ch [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The main problems connected with the deformation of metals due to extrusion are described. A method is put forward for calculating the rational rate of percentage deformation in the case of bar extrusion using a cylindrical container; reference is made to previous work on extrusion using a hydrostatic pressure with or without back-pressure. An extrusion process is described using hydrostatic pressure, without back-pressure, and using the lubricant for transmitting the thrust. This process has been used for eight years by the C.E.A. for the extrusion of a very wide range of metals, from beryllium to uranium and including steels; it leads to excellent surface textures. A very fine crystallization can be obtained on extruded products when the rate of extrusion is very low. There appears to be nothing against the use of high extrusion rates using this method. (author) [French] On expose les problemes generaux lies a la deformation des metaux par filage. On propose un calcul de la vitesse rationnelle de deformation pour cent dans le cas du filage de barres a partir d'un conteneur cylindrique, et l'on cite les travaux anterieurs sur le filage par faction d'une pression hydrostatique sans ou avec une contre-pression. On decrit un procede de filage par l'action d'une pression hydrostatique, sans contre-pression, utilisant le lubrifiant pour transmettre la poussee. Ce procede employe depuis 8 ans au C.E.A. pour filer les metaux les plus divers, depuis le beryllium jusqu'a l'uranium en passant par les aciers, permet d'obtenir d'excellents etats de surface. Une cristallisation tres fine peut etre obtenue sur les produits files lorsque le filage est tres lent. Rien ne parait s'opposer a ce que des filages rapides soient effectues avec cette methode. (auteur)

  9. Optical Measurement Technology For Aluminium Extrusions

    International Nuclear Information System (INIS)

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

    2007-01-01

    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 shape 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

  10. Uncertainty principle for angular position and angular momentum

    International Nuclear Information System (INIS)

    Franke-Arnold, Sonja; Barnett, Stephen M; Yao, Eric; Leach, Jonathan; Courtial, Johannes; Padgett, Miles

    2004-01-01

    The uncertainty principle places fundamental limits on the accuracy with which we are able to measure the values of different physical quantities (Heisenberg 1949 The Physical Principles of the Quantum Theory (New York: Dover); Robertson 1929 Phys. Rev. 34 127). This has profound effects not only on the microscopic but also on the macroscopic level of physical systems. The most familiar form of the uncertainty principle relates the uncertainties in position and linear momentum. Other manifestations include those relating uncertainty in energy to uncertainty in time duration, phase of an electromagnetic field to photon number and angular position to angular momentum (Vaccaro and Pegg 1990 J. Mod. Opt. 37 17; Barnett and Pegg 1990 Phys. Rev. A 41 3427). In this paper, we report the first observation of the last of these uncertainty relations and derive the associated states that satisfy the equality in the uncertainty relation. We confirm the form of these states by detailed measurement of the angular momentum of a light beam after passage through an appropriate angular aperture. The angular uncertainty principle applies to all physical systems and is particularly important for systems with cylindrical symmetry

  11. Study on reactive extrusion processes of block copolymer

    International Nuclear Information System (INIS)

    Wu Lili; Jia Yuxi; Sun Sheng; Zhang Guofang; Zhao Guoqun; An Lijia

    2007-01-01

    The anionic copolymerization process of styrene-butadiene (S/B) block copolymer in a closely intermeshing co-rotating twin screw extruder with butyl-lithium initiator was studied. According to the anionic copolymerization mechanism and the reactive extrusion characteristics, the mathematical models of monomer conversion, average molecular weight and fluid viscosity during the anionic copolymerization of S/B were constructed, and then the reactive extrusion process was simulated by means of the finite volume method and the uncoupled semi-implicit iterative algorithm. Finally, the influence of the feeding mixture composition on conversion was discussed. The simulated results were nearly in agreement with the experimental results

  12. Measurement of Fission Fragment Angular Distributions for 14 N+ 232 Th and 11 B+ 235 U at Near-Barrier Energies

    International Nuclear Information System (INIS)

    Behera, B.R.; Jena, S.; Satapathy, M.; Ison, V.V.; Kailas, S.; Chatterjee, A.; Shrivastava, A.; Mahata, K.; Satpathy, L.; Basu, P.; Roy, S.; Sharan, M.; Chatterjee, M.L; Datta, S.K.

    2000-01-01

    Fission fragment angular distributions of heavy-ion induced fission in actinide nuclei at near-barrier energies show anomalous fragment anisotropies. At above barrier energies entrance channel dependence is a probable cause and explanation in terms of pre-equilibrium fission and the critical mass asymmetry parameter (Businaro-Gallone) has been tried. Target deformation and ground state spin also seem to influence the measured anisotropy. To understand the extent of importance of some or all of these features, we performed a set of experiments where (i) entrance channel dependence (ii) mass asymmetry on the two sides of Businaro-Gallone and (iii) different ground state spins are present. The channels chosen are 14 N+ 232 Th and 11 B+ 235 U. Experiments were done using the Pelletron accelerators at NSC, New Delhi and BARC-TIFR, Bombay. Compound nucleus populated in both cases is 246 Bk. 232 Th has ground state spin zero and 235 U has spin 7/2. Fragment anisotropies have been measured from 10-15 % above barrier to 10 % below barrier at similar excitation energy (around 40 MeV to 58 MeV). The mean square angular momentum is matched at least at one energy. Results indicate that when both excitation energy and angular momentum are matched, there are differences in the measured values of fission anisotropies. This implies entrance channel dependence consistent with the expectation of pre-equilibrium fission model. (authors)

  13. Extrusion and properties of lead zirconate titanate piezoelectric ceramics

    DEFF Research Database (Denmark)

    Cai, S.; Millar, C.E.; Pedersen, L.

    1997-01-01

    The purpose of this work was to develop a procedure for fabricating electroceramic actuators with good piezoelectric properties. The preparation of lead zirconate titanate (PZT) piezoelectric ceramic rods and tubes by extrusion processing is described. The microstructure of extrudates was investi......The purpose of this work was to develop a procedure for fabricating electroceramic actuators with good piezoelectric properties. The preparation of lead zirconate titanate (PZT) piezoelectric ceramic rods and tubes by extrusion processing is described. The microstructure of extrudates...

  14. Improvement of mechanical properties and corrosion resistance of biodegradable Mg-Nd-Zn-Zr alloys by double extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaobo, E-mail: xbxbzhang2003@163.com [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China); Wang, Zhangzhong [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China); Yuan, Guangyin [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai, 200240 (China); Xue, Yajun [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China)

    2012-08-01

    Highlights: Black-Right-Pointing-Pointer Microstructure of Mg-Nd-Zn-Zr alloys was refined and homogenized by double extrusion process. Black-Right-Pointing-Pointer The mechanical properties of the alloys were significantly enhanced by double extrusion. Black-Right-Pointing-Pointer The biocorrosion resistance of the alloys was improved by double extrusion. - Abstract: Mg-Nd-Zn-Zr alloy is a novel and promising biodegradable magnesium alloy due to good biocompatibility, desired uniform corrosion mode and outstanding corrosion resistance in simulated body fluid (SBF). However, the corrosion resistance and mechanical properties should be improved to meet the requirement of the biodegradable implants, such as plates, screws and cardiovascular stents. In the present study, double extrusion process was adopted to refine microstructure and improve mechanical properties of Mg-2.25Nd-0.11Zn-0.43Zr and Mg-2.70Nd-0.20Zn-0.41Zr alloys. The corrosion resistance of the alloys after double extrusion was also studied. The results show that the microstructure of the alloys under double extrusion becomes much finer and more homogeneous than those under once extrusion. The yield strength, ultimate tensile strength and elongation of the alloys under double extrusion are over 270 MPa, 300 MPa and 32%, respectively, indicating that outstanding mechanical properties of Mg-Nd-Zn-Zr alloy can be obtained by double extrusion. The results of immersion experiment and electrochemical measurements in SBF show that the corrosion resistance of Alloy 1 and Alloy 2 under double extrusion was increased by 7% and 8% respectively compared with those under just once extrusion.

  15. Improvement of mechanical properties and corrosion resistance of biodegradable Mg–Nd–Zn–Zr alloys by double extrusion

    International Nuclear Information System (INIS)

    Zhang, Xiaobo; Wang, Zhangzhong; Yuan, Guangyin; Xue, Yajun

    2012-01-01

    Highlights: ► Microstructure of Mg–Nd–Zn–Zr alloys was refined and homogenized by double extrusion process. ► The mechanical properties of the alloys were significantly enhanced by double extrusion. ► The biocorrosion resistance of the alloys was improved by double extrusion. - Abstract: Mg–Nd–Zn–Zr alloy is a novel and promising biodegradable magnesium alloy due to good biocompatibility, desired uniform corrosion mode and outstanding corrosion resistance in simulated body fluid (SBF). However, the corrosion resistance and mechanical properties should be improved to meet the requirement of the biodegradable implants, such as plates, screws and cardiovascular stents. In the present study, double extrusion process was adopted to refine microstructure and improve mechanical properties of Mg–2.25Nd–0.11Zn–0.43Zr and Mg–2.70Nd–0.20Zn–0.41Zr alloys. The corrosion resistance of the alloys after double extrusion was also studied. The results show that the microstructure of the alloys under double extrusion becomes much finer and more homogeneous than those under once extrusion. The yield strength, ultimate tensile strength and elongation of the alloys under double extrusion are over 270 MPa, 300 MPa and 32%, respectively, indicating that outstanding mechanical properties of Mg–Nd–Zn–Zr alloy can be obtained by double extrusion. The results of immersion experiment and electrochemical measurements in SBF show that the corrosion resistance of Alloy 1 and Alloy 2 under double extrusion was increased by 7% and 8% respectively compared with those under just once extrusion.

  16. Effect of equal channel angular pressing on in vitro degradation of LAE442 magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Minárik, Peter, E-mail: peter.minarik@mff.cuni.cz [Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic); Jablonská, Eva [Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6 (Czech Republic); Král, Robert [Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic); Lipov, Jan; Ruml, Tomáš [Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6 (Czech Republic); Blawert, Carsten [Helmholtz-Zentrum Geesthacht, Zentrum für Material- und Küstenforschung GmbH, Institut für Werkstoffforschung, Max-Planck-Straße 1, Geesthacht (Germany); Hadzima, Branislav [University of Žilina, Univerzitná 8215/1, 010 26 Žilina (Slovakia); Chmelík, František [Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic)

    2017-04-01

    Effect of processing by equal channel angular pressing (ECAP) on the degradation behaviour of extruded LAE442 magnesium alloy was investigated in a 0.1 M NaCl solution, Kirkland's biocorrosion medium (KBM) and Minimum Essential Medium (MEM), both with and without 10% of foetal bovine serum (FBS). Uniform degradation of as extruded and ECAP processed samples in NaCl solution was observed, nevertheless higher corrosion resistance was found in the latter material. The increase of corrosion resistance due to ECAP was observed also after 14-days immersion in all media used. Higher compactness of the corrosion layer formed on the samples after ECAP was responsible for the observed decrease of corrosion resistance, which was proven by scanning electron microscope investigation. Lower corrosion rate in media with FBS was observed and was explained by additional effect of protein incorporation on the corrosion layer stability. A cytotoxicity test using L929 cells was carried out to investigate possible effect of processing on the cell viability. Sufficient cytocompatibility of the extruded samples was observed with no adverse effects of the subsequent ECAP processing. In conclusion, this in vitro study proved that the degradation behaviour of the LAE442 alloy could be improved by subsequent ECAP processing and this material is a good candidate for future in vivo investigation. - Highlights: • ECAP processing decelerates the corrosion rate of the LAE442 magnesium alloy. • Corrosion layers formed on the samples after ECAP have higher compactness. • No cytotoxic effect of extracts prepared from LAE442 after both types of processing was observed.

  17. Effect of equal channel angular pressing on in vitro degradation of LAE442 magnesium alloy

    International Nuclear Information System (INIS)

    Minárik, Peter; Jablonská, Eva; Král, Robert; Lipov, Jan; Ruml, Tomáš; Blawert, Carsten; Hadzima, Branislav; Chmelík, František

    2017-01-01

    Effect of processing by equal channel angular pressing (ECAP) on the degradation behaviour of extruded LAE442 magnesium alloy was investigated in a 0.1 M NaCl solution, Kirkland's biocorrosion medium (KBM) and Minimum Essential Medium (MEM), both with and without 10% of foetal bovine serum (FBS). Uniform degradation of as extruded and ECAP processed samples in NaCl solution was observed, nevertheless higher corrosion resistance was found in the latter material. The increase of corrosion resistance due to ECAP was observed also after 14-days immersion in all media used. Higher compactness of the corrosion layer formed on the samples after ECAP was responsible for the observed decrease of corrosion resistance, which was proven by scanning electron microscope investigation. Lower corrosion rate in media with FBS was observed and was explained by additional effect of protein incorporation on the corrosion layer stability. A cytotoxicity test using L929 cells was carried out to investigate possible effect of processing on the cell viability. Sufficient cytocompatibility of the extruded samples was observed with no adverse effects of the subsequent ECAP processing. In conclusion, this in vitro study proved that the degradation behaviour of the LAE442 alloy could be improved by subsequent ECAP processing and this material is a good candidate for future in vivo investigation. - Highlights: • ECAP processing decelerates the corrosion rate of the LAE442 magnesium alloy. • Corrosion layers formed on the samples after ECAP have higher compactness. • No cytotoxic effect of extracts prepared from LAE442 after both types of processing was observed.

  18. Suitability of the Yield Criterion in Numerical Simulation of Stretch Bending of Aluminum Extrusions

    International Nuclear Information System (INIS)

    Li, X.Q.; Zhou, X.B.; Wu, X.D.; Gao, H.Z.

    2005-01-01

    Stretch bending is commonly used to shape thin-walled extrusions in aerospace and automotive industries. The extrusions are pre-stretched and bent over rigid curved dies. Effective application of this process demands sufficient knowledge of how different parameters influence the final shape of the product. Numerical simulation is an effective approach to investigate these issues presently. However, the validity of simulation result depends strongly on a precise description of the mechanical behavior of the material. Due to crystallographic texture caused by the extrusion process, aluminium extrusions exhibit significant plastic anisotropy which need be described by advanced constitutive model. In this work stretch bending of aluminum extrusions is simulated by using different anisotropic criteria (Hill quadratic, Barlat three-parameter). The influence of two yield criteria on predicting maximum die force immediately before unloading, permanent sagging and vertical springback displacement in the middle section of extrusion are compared. Maximum die force and springback calculated by two yield criteria are found to be almost same. Permanent sagging is obviously underestimated by two yield criteria, however, prediction by Barlat three-parameter is closer to experiment than one of Hill quadratic yield criterion

  19. Current deformation rates and extrusion of the northwestern Okhotsk plate, northeast Russia

    Science.gov (United States)

    Hindle, D.; Fujita, K.; Mackey, K.

    2006-01-01

    Northeast Asia is a region of broad deformation resulting from the convergence of the Eurasian (EU) and North American (NA) plates. Part of this convergence has been suggested to be relieved by the extrusion and deformation of the Okhotsk plate (OK). Three models for the deformation of the seismically active northwestern corner of the Okhotsk plate, based on different modes of deformation partitioning, are calculated and compared to observations from GPS, seismicity, and geology. The results suggest that this region is being extruded southeastward and deforming internally by a mixture of pure contraction, ``smooth'' extrusion, and ``rigid'' extrusion. Calculated extrusion rates are ~3-5.5 mm/yr, comparable to estimates from geologic data, and internal deformation rates are ~3.0 × 10-9 yr -1. Internal deformation may be only partially accommodated by seismicity, but the short time span of seismic data leaves this subject to large uncertainty.

  20. Prediction of extrusion die wear by use of an artificial neural network

    International Nuclear Information System (INIS)

    Naidim, O.; Epureanu, A.; Tabacaru, V.

    2000-01-01

    In its vision of designing a technology, the process of optimisation of a material extrusion is an on-line process. The tool life is an important factor in selecting the objective function that represents the cost of the extruded product. This work is intended to realise the prediction of die wear evolution within the extrusion process, based on information obtained from numerical modelling. In order to reduce the number of experiments and to realise a flexible process of designing the necessary tools for an extrusion process, finite element (FE) modelling was used to determine designing space against the shape of the extruded product, the work conditions, the material and wear conditions. The information generated using FE was then used to train a neural network using backpropagation algorithm. Parameters considered in constructing neural networks include error tolerance, the factor of estimation of the 'best solution', the number of training cycles and the number of hidden layers. A general formula of calculus applicable in any extrusion process can be determined by establishing a relation between the stress state obtained within the extrusion process, deformation speed and friction on one hand, and wear on the other hand. The (1/W) parameter, where W is the tool wear in the active zone of the extrusion die, is a measure taken into account in calculating the die life as written in (1); this is the reason why it is important to make prediction of W value for geometries used in designing process or to optimise the die shape in order to reduce wear. (author)

  1. Deformations in micro extrusion of metals

    Directory of Open Access Journals (Sweden)

    J. Piwnik

    2010-07-01

    Full Text Available Production technologies of small dimensions metallic elements are known for a long time. They are produced by machining methods:turning, milling, polishing. Recently, methods for manufacturing small details by forming are developed – microforming. This process ischaracterized by the high dimensions accuracy and the surface smoothness of received items and the high production rate. When a forming process is scaled down to micro dimensions, the microstructure of the workpiece, the surface topology of the workpiece and that of the tooling remain unchanged. Size effect is appearing. This paper analyses specifications of a metal extrusion in micro scale. To determine the impact of the tool surface roughness on deformation process the numerical model of roughness as triangle wave were developed. In paper the influence of the wave presence on the material flow is described. Impact of the forming conditions on extrusion forces there is also characterized.

  2. Extrusion and drawing of zircaloy 2. Production of pressure tubes for EL-4

    International Nuclear Information System (INIS)

    Thevenet, J.

    1964-01-01

    The authors give briefly the physical mechanical and chemical properties of zircaloy 2, as far as the transformation of this alloy is concerned. Extrusion: After a few general remarks concerning the extrusion and co-extrusion, including a comparison of the deformation resistance of canning metals and of zircaloy 2, the following points are considered: - the difficulties occurring because of the use of this alloy: - atmosphere protection - adjustment on to the machine tools - low thermal conductivity - economy of the metal (price) - the factors affecting the quality of the extruded products extrusion under a copper can and under lubricant glass - fine grain structure - temperature homogeneity - working temperature The transformation cycle - '550 kg ingot - preliminary shape 'for drawing of EL-4 tubes (112 x 120 L 12 m)' - is described in detail (extrusion or forging of the φ = 340 ingot into φ = 220 billets, cutting into lengths and hot drilling at φ = 125, fixing into a copper can and rough extrusion). Drawing: The main difficulties are due to seizing of the tools and to the necessity of protecting the alloy from the atmosphere during annealings. A brief description is given of drawing out on a short mandrel, on a long mandrel, of laminating on a reducing machine and of the carrying out of an annealing, as well as of the production of EL-4 tubes (φ =107 x 113 L 430 m) by drawing out shapes having a size of 112 x 120 on long mandrels. Conclusion: It is possible by extrusion and drawing to produce zircaloy 2 tubes similar to those which may be obtained normally using stainless steel. (authors) [fr

  3. Cervical artificial disc extrusion after a paragliding accident.

    Science.gov (United States)

    Niu, Tianyi; Hoffman, Haydn; Lu, Daniel C

    2017-01-01

    Cervical total disc replacement (TDR) is an established alternative to anterior cervical discectomy and fusion (ACDF) with excellent long-term outcomes and low failure rates. Cases of implant failure and migration are scarce and primarily limited to several years postoperatively. The authors report a case of anterior extrusion of a C4-C5 ProDisc-C (DePuy Synthes, West Chester, PA, USA) cervical artificial disc (CAD) 14 months after placement due to minor trauma. A 33-year-old female who had undergone C4-C5 CAD implantation presented with neck pain and spasm after experiencing a paragliding accident. A 4 mm anterior protrusion of the CAD was seen on x-ray. She underwent removal of the CAD followed by anterior fusion. Other cases of CAD extrusion in the literature are discussed and the device's durability and testing are considered. Overall, CAD extrusion is a rare event. This case is likely the result of insufficient osseous integration. Patients undergoing cervical TDR should avoid high-risk activities to prevent trauma that could compromise the disc's placement, and future design/research should focus on how to enhance osseous integration at the interface while minimizing excessive heterotopic ossification.

  4. Extrusion-mixing compared with hand-mixing of polyether impression materials?

    Science.gov (United States)

    McMahon, Caroline; Kinsella, Daniel; Fleming, Garry J P

    2010-12-01

    The hypotheses tested were two-fold (a) whether altering the base:catalyst ratio influences working time, elastic recovery and strain in compression properties of a hand-mixed polyether impression material and (b) whether an extrusion-mixed polyether impression material would have a significant advantage over a hand-mixed polyether impression material mixed to the optimum base:catalyst ratio. The polyether was hand-mixed at the optimum (manufacturers recommended) base:catalyst ratios (7:1) and further groups were made by increasing or decreasing the catalyst length by 25%. Additionally specimens were also made from an extrusion-mixed polyether impression material and compared with the optimum hand-mixed base:catalyst ratio. A penetrometer assembly was used to measure the working time (n=5). Five cylindrical specimens for each hand-mixed and extrusion mixed group investigated were employed for elastic recovery and strain in compression testing. Hand-mixing polyether impression materials with 25% more catalyst than that recommended significantly decreased the working time while hand-mixing with 25% less catalyst than that recommended significantly increased the strain in compression. The extrusion-mixed polyether impression material provided similar working time, elastic recovery and strain in compression to the hand-mixed polyether mixed at the optimum base:catalyst ratio.

  5. Statistical reliability analyses of two wood plastic composite extrusion processes

    International Nuclear Information System (INIS)

    Crookston, Kevin A.; Mark Young, Timothy; Harper, David; Guess, Frank M.

    2011-01-01

    Estimates of the reliability of wood plastic composites (WPC) are explored for two industrial extrusion lines. The goal of the paper is to use parametric and non-parametric analyses to examine potential differences in the WPC metrics of reliability for the two extrusion lines that may be helpful for use by the practitioner. A parametric analysis of the extrusion lines reveals some similarities and disparities in the best models; however, a non-parametric analysis reveals unique and insightful differences between Kaplan-Meier survival curves for the modulus of elasticity (MOE) and modulus of rupture (MOR) of the WPC industrial data. The distinctive non-parametric comparisons indicate the source of the differences in strength between the 10.2% and 48.0% fractiles [3,183-3,517 MPa] for MOE and for MOR between the 2.0% and 95.1% fractiles [18.9-25.7 MPa]. Distribution fitting as related to selection of the proper statistical methods is discussed with relevance to estimating the reliability of WPC. The ability to detect statistical differences in the product reliability of WPC between extrusion processes may benefit WPC producers in improving product reliability and safety of this widely used house-decking product. The approach can be applied to many other safety and complex system lifetime comparisons.

  6. Angular correlation, spin alignment, and systematics of mis-matched {sup 12}C+{sup 12}C inelastic scattering resonances

    Energy Technology Data Exchange (ETDEWEB)

    Wuosmaa, A.H.; Wiedenhoever, I.; Caggiano, J.; Carpenter, M.P.; Devlin, M.; Heinz, A.; Janssens, R.V.F.; Kondev, F.; Lauritsen, T.; Sarantites, D.G.; Sobotka, L.G.; Battacharyya, P

    2003-10-09

    Particle gamma-ray angular correlation measurements have been used to study the spin alignment and magnetic-substate population parameters for the 2{sup +}{sub 1} (4.443 MeV) state in {sup 12}C, populated in the {sup 12}C({sup 12}C,{sup 12}C[0{sup +}{sub 2}]){sup 12}C(2{sup +}{sub 1}) inelastic scattering reaction in the vicinity of a prominent, narrow peak in the scattering excitation function. The data show a strong alignment of the spin with the orbital angular momentum, and suggest that the cross section peak corresponds to a spin 14{sup +} resonance at E{sub c.m.}=28.0 MeV. This energy is close to that where a strong peak is also observed in the 0{sup +}{sub 1}+0{sup +}{sub 2} excitation function. A comparison between the data for these two channels lends some support to recent theoretical calculations of resonance behavior for angular-momentum-mismatched channels in {sup 12}C+{sup 12}C inelastic scattering.

  7. Molecular type channeling of relativistic electrons in crystals

    International Nuclear Information System (INIS)

    Vyatkin, E.G.; Filimonov, Yu.M.; Taratin, A.M.; Vorobiev, S.A.

    1983-01-01

    Channeling of relativistic electrons in direction in a diamond crystal and the channeling radiation spectra are investigated using computer simulation by the binary collision model and using the model of a continuum potential of the atomic rows. In a computer experiment the atomic- and molecular-type states of channeled elcetrons are revealed, and the orientational dependence of the electron trapping probability in these states is obtained. The peculiarities revealed of the angular distributions and radiation spectra of electrons in the molecular-type states allow to discover these states in the experiment. (author)

  8. Effect of equal channel angular pressing on the microstructure and mechanical properties of Al-10Zn-2Mg alloy

    Science.gov (United States)

    Manjunath, G. K.; Kumar, G. V. Preetham; Bhat, K. Udaya

    2018-04-01

    The current investigation is focused on evaluating the mechanical properties and the microstructure of cast Al-10Zn-2Mg alloy processed through equal channel angular pressing (ECAP). The ECAP processing was attempted at minimum possible processing temperature. Microstructural characterization was carried out in optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction analysis. Hardness measurement and tensile tests were employed to estimate the mechanical properties. Experimental results showed that, ECAP processing leads to noticeable grain refinement in the alloy. Reasonable amount of dislocations were observed in the ECAP processed material. After ECAP processing, precipitates nucleation in the material was detected in the XRD analysis. ECAP leads to considerable enhancement in the mechanical properties of the material. After ECAP processing, microhardness of the material is increased from 144 Hv to 216 Hv. Also, after ECAP processing the UTS of the material is increased from 140 MPa to 302 MPa. The increase in the mechanical properties of the alloy after ECAP processing is due to the dislocation strengthening and grain refinement strengthening. Finally, fracture surface morphology of the tensile test samples also studied.

  9. Influence of Route-R on wrought magnesium AZ61 alloy mechanical properties through equal channel angular pressing

    Directory of Open Access Journals (Sweden)

    Muralidhar Avvari

    2014-06-01

    Full Text Available A new fundamental route entitled ‘Route-R’ is introduced to refine the grains in the material through Equal Channel Angular Pressing (ECAP process. In route R, specimen is inverted to the original position in each ECAP pass. In the present work, AZ61 alloy is processed using ECAP process for three different fundamental routes mainly route A, route Bc, and route R. ECAP experiment is carried out on AZ61 alloy at lower temperature of 483 K up to two passes. Microstructural characterization is evaluated on unECAPed and ECAPed specimens for three routes. Average grain size of the alloy is to be reduced from 66 μm to 16 μm, 14.1 μm and 10 μm for route A routes Bc, and route R respectively. Vickers microhardness of the alloy is found to be 60 HV for as received material. This microhardness of the alloy is increased to 71 HV, 72 HV, and 74 HV for route A, route Bc, and route R respectively. Mechanical properties of the AZ61 alloy are observed to be route R is providing maximum YS, UTS, and percentage elongation than other route A and route Bc. Tensile fracture topography of the specimen is analyzed using three different routes for two passes.

  10. Effect of rapid cooling and extrusion ratio on the mechanical property of Mg alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taek-Soo, E-mail: tskim@kitech.re.k [Center for Echo Materials and Processing, Korea Institute of Industrial Technology, 7-47 Techno-park Songdo, Incheon 406-130 (Korea, Republic of)

    2010-08-15

    Mg{sub 95}Zn{sub 4.3}Y{sub 0.7} (at.%) alloy powders were prepared using an inert gas atomizer, followed by warm extrusion. The powders were almost spherical in shape, and the grain size, compared with the cast product, was fine being less than 5 {mu}m. The microstructure of bars extruded was examined as a function of the extrusion ratio using scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDS) and X-ray diffractometer (XRD). As the extrusion ratio increased from 10:1 to 20:1, the powders fully deformed with refining the grain size. Both the ultimate strength and elongation also showed a dependence on the extrusion ratio.

  11. Angular analyses of $b \\to s \\mu^+ \\mu^-$ transitions at CMS

    CERN Document Server

    Wang, Dayong

    2018-01-01

    The flavour changing neutral current decays can be interesting probes for searching for new physics. Angular distributions of $b \\to s \\ell^+ \\ell^-$ transition processes of both $\\mathrm{B}^0 \\to \\mathrm{K}^{*0} \\mu^ +\\mu^-$ and $\\mathrm{B}^{+} \\to \\mathrm{K}^{+} \\mu^+\\mu^-$ are studied using a sample of proton-proton collisions at $\\sqrt{s} = 8~\\mathrm{TeV}$ collected with the CMS detector at the LHC, corresponding to an integrated luminosity of $20.5~\\mathrm{fb}^{-1}$. Angular analyses are performed to determine $P_1$ and $P_5'$ angular parameters for $\\mathrm{B}^0 \\to \\mathrm{K}^{*0} \\mu^ +\\mu^-$ and $A_{FB}$ and $F_{H}$ parameters for $\\mathrm{B}^{+} \\to \\mathrm{K}^{+} \\mu^+\\mu^-$, all as functions of the dimuon invariant mass squared. The $P_5'$ parameter is of particular interest due to recent measurements that indicate a potential discrepancy with the standard model. All the measurements are consistent with the standard model predictions. Efforts with more channels and more coming data will be con...

  12. Melting, casting, and alpha-phase extrusion of the uranium-2.4 weight percent niobium alloy

    International Nuclear Information System (INIS)

    Anderson, R.C.; Beck, D.E.; Kollie, T.G.; Zorinsky, E.J.; Jones, J.M.

    1981-10-01

    The experimental details of the melting, casting, homogenization, and alpha-phase extrusion process used to fabricate the uranium-2.4 wt % niobium alloy into 46-mm-diameter rods is described. Extrusion defects that were detected by an ultrasonic technique were eliminated by proper choice of extrusion parameters; namely, reduction ratio, ram speed, die angle, and billet preheat temperature

  13. 75 FR 73041 - Aluminum Extrusions From the People's Republic of China: Postponement of Final Determination of...

    Science.gov (United States)

    2010-11-29

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-967] Aluminum Extrusions From the... investigation of aluminum extrusions from the People's Republic of China (``PRC'') on April 27, 2010.\\1\\ On..., 2011. \\1\\ See Aluminum Extrusions from the People's Republic of China: Initiation of Antidumping Duty...

  14. 75 FR 34982 - Aluminum Extrusions from the People's Republic of China: Notice of Postponement of Preliminary...

    Science.gov (United States)

    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...

  15. Bio-Inspired Micro-Fluidic Angular-Rate Sensor for Vestibular Prostheses

    Directory of Open Access Journals (Sweden)

    Charalambos M. Andreou

    2014-07-01

    Full Text Available This paper presents an alternative approach for angular-rate sensing based on the way that the natural vestibular semicircular canals operate, whereby the inertial mass of a fluid is used to deform a sensing structure upon rotation. The presented gyro has been fabricated in a commercially available MEMS process, which allows for microfluidic channels to be implemented in etched glass layers, which sandwich a bulk-micromachined silicon substrate, containing the sensing structures. Measured results obtained from a proof-of-concept device indicate an angular rate sensitivity of less than 1 °/s, which is similar to that of the natural vestibular system. By avoiding the use of a continually-excited vibrating mass, as is practiced in today’s state-of-the-art gyroscopes, an ultra-low power consumption of 300 μW is obtained, thus making it suitable for implantation.

  16. Osmotic mechanism of the loop extrusion process

    Science.gov (United States)

    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.

  17. Apical extrusion of debris in four different endodontic instrumentation systems: A meta-analysis.

    Science.gov (United States)

    Western, J Sylvia; Dicksit, Daniel Devaprakash

    2017-01-01

    All endodontic instrumentation systems tested so far, promote apical extrusion of debris, which is one of the main causes of postoperative pain, flare ups, and delayed healing. Of this meta-analysis was to collect and analyze in vitro studies quantifying apically extruded debris while using Hand ProTaper (manual), ProTaper Universal (rotary), Wave One (reciprocating), and self-adjusting file (SAF; vibratory) endodontic instrumentation systems and to determine methods which produced lesser extrusion of debris apically. An extensive electronic database search was done in PubMed, Scopus, Cochrane, LILACS, and Google Scholar from inception until February 2016 using the key terms "Apical Debris Extrusion, extruded material, and manual/rotary/reciprocating/SAF systems." A systematic search strategy was followed to extract 12 potential articles from a total of 1352 articles. The overall effect size was calculated from the raw mean difference of weight of apically extruded debris. Statistically significant difference was seen in the following comparisons: SAF ProTaper. Apical extrusion of debris was invariably present in all the instrumentation systems analyzed. SAF system seemed to be periapical tissue friendly as it caused reduced apical extrusion compared to Rotary ProTaper and Wave One.

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

    Science.gov (United States)

    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.

  19. Simulation of planar channeling-radiation spectra of relativistic electrons and positrons channeled in a diamond-structure or tungsten single crystal (classical approach)

    International Nuclear Information System (INIS)

    Azadegan, B.; Wagner, W.

    2015-01-01

    We present a Mathematica package for simulation of spectral-angular distributions and energy spectra of planar channeling radiation of relativistic electrons and positrons channeled along major crystallographic planes of a diamond-structure or tungsten single crystal. The program is based on the classical theory of channeling radiation which has been successfully applied to study planar channeling of light charged particles at energies higher than 100 MeV. Continuous potentials for different planes of diamond, Si, Ge and W single crystals are calculated using the Doyle–Turner approximation to the atomic scattering factor and taking thermal vibrations of the crystal atoms into account. Numerical methods are applied to solve the classical one-dimensional equation of motion. The code is designed to calculate the trajectories, velocities and accelerations of electrons (positrons) channeled by the planar continuous potential. In the framework of classical electrodynamics, these data allow realistic simulations of spectral-angular distributions and energy spectra of planar channeling radiation. Since the generated output is quantitative, the results of calculation may be useful, e.g., for setup configuration and crystal alignment in channeling experiments, for the study of the dependence of channeling radiation on the input parameters of particle beams with respect to the crystal orientation, but also for the simulation of positron production by means of pair creation what is mandatory for the design of efficient positron sources necessary in high-energy and collider physics. Although the classical theory of channeling is well established for long time, there is no adequate library program for simulation of channeling radiation up to now, which is commonly available, sufficiently simple and effective to employ and, therefore, of benefit as for special investigations as for a quick overview of basic features of this type of radiation

  20. Fission via compound states and JπK A. Bohr's channels: what we can learn from recent studies with slow neutrons

    Directory of Open Access Journals (Sweden)

    Furman W.I.

    2012-02-01

    Full Text Available Last data on angular correlations of fission fragments from slow (s-wave neutron induced binary fission of spin-aligned nuclei 235U are discussed in the context of JπK A. Bohrs channels. Special attention is paid to K = 0 channel. Reasons for its suppression are specified for compound nucleus states of negative parity. A brief overview of recent data on T-odd angular correlations in ternary and binary (with emission of a third particle, a neutron or γ-quantum fission induced by slow polarized neutrons is presented. On the basis of the developed theoretical approach it is shown that a valuable information on JπK fission channels at scission point can be inferred from these T-odd angular correlations.

  1. Feasibility of attaining uniform grain structure and enhanced ductility in aluminum alloy by employing a beveled punch in equal-channel angular pressing

    Energy Technology Data Exchange (ETDEWEB)

    Nejadseyfi, Omid, E-mail: o.nejadseyfi@gmail.com [Advanced Materials and Nanotechnology Research Lab, Department of Mechanical Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Shokuhfar, Ali [Advanced Materials and Nanotechnology Research Lab, Department of Mechanical Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Sadeghi, Seyedali [Department of Mechanical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2016-01-10

    The advantage of using a beveled-edge punch in equal-channel angular pressing is investigated. Lambda angle (λ), the clockwise angle between the theoretical shear plane and punch/billet interface, is used to demonstrate how the punch tip is inclined. Transmission electron microscope is used to assess the microstructure of the samples processed using a beveled-edge punch. In addition, tensile tests at elevated temperature are performed. The results show that using a beveled-edge punch (λ=90°) in the process leads to formation of uniform subgrain structure and increases the tensile ductility for the samples at elevated temperature. Additionally, finite element simulations are performed to study the correlation between measured properties and mechanism of material deformation by employing a beveled-edge punch. Numerical simulations confirm the irregular deformation in case of λ=0° and uniform strain distribution for λ=90°, which were the main reasons of variation in mechanical properties.

  2. A simulation study of antimatter-helium ion planar channeling in silicon

    International Nuclear Information System (INIS)

    Wijesundera, Dharshana; Jayarathna, Sandun; Bellwied, Rene; Chu, Wei-Kan

    2012-01-01

    With the physical significance arising with the reports on experimental observation of antimatter-He nuclei, we have investigated a case of 2 MeV antimatter-He ion planar channeling in Si (1 0 0) in comparison with He channeling, by simulation. For a negatively charged antimatter-He nucleus, the planar potential well is centered at the atomic plane itself as opposed to the center-channel minimum for He ions; the antimatter-He ion distribution therefore tends to concentrate toward the atomic lattice planes. The antimatter-He ion flux distribution and the resulting close encounter probability are crucial in determining the probability of close encounter events including annihilation at channeling incidence. We have therefore analyzed the variation of antimatter-He ion flux distribution within the channels with respect to the angle of incidence and have thereby derived the orientation dependence of probability of close encounter events, or an antimatter-He channeling angular scan. The angular scan is inverted with a maximum yield at the perfect beam-planar alignment. The half-angle is narrower compared to He channeling, as a consequence of the narrower planar channeling potential centered at the lattice planes. The high de-channeling rate associated with the higher antimatter-He ion concentration in the proximity of lattice planes causes the maximum yield to be less prominent and to decrease rapidly with depth. The shoulder region shows strong depth dependent reduction that can be associated to near surface depth dependent ion flux variation.

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

    Science.gov (United States)

    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 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.

  4. Quantum Channeling Effects for 1 MeV Positrons

    International Nuclear Information System (INIS)

    Haakenaasen, R.; Vestergaard Hau, L.; Golovchenko, J.A.; Palathingal, J.C.; Peng, J.P.; Asoka-Kumar, P.; Lynn, K.G.

    1995-01-01

    A high resolution angular study of positrons transmitted through a thin single crystal of Si clearly reveals a detailed fine structure due to strong quantum channeling effects. The beam transmitted in the forward direction displays many features associated with dynamical diffraction effects and long coherence lengths. Calculations are presented showing that in flight annihilation of channeled positrons can serve as a solid state probe of electron and spin densities in thin crystals

  5. Coupled analysis of material flow and die deflection in direct aluminum extrusion

    NARCIS (Netherlands)

    Assaad, W.; Geijselaers, Hubertus J.M.

    2010-01-01

    The design of extrusion dies depends on the experience of the designer. After the die has been manufactured, it is tested during an extrusion trial and machined several times until it works properly. The die is designed by a trial and error method which is an expensive process in terms of time and

  6. Coherent radiation from atoms and a channeled particle

    International Nuclear Information System (INIS)

    Epp, V.; Sosedova, M.A.

    2013-01-01

    Highlights: ► Impact of coherent atoms vibrations on radiation of a channeled particle is studied. ► Resonant amplification of atomic radiation is possible under certain conditions. ► Radiation of vibrating atoms forms an intense narrow peak in angular distribution. ► Radiation of atoms on resonance conditions is higher than that of channeled particle. -- Abstract: A new mechanism of radiation emitted at channeling of a relativistic charged particle in a crystal is studied. The superposition of coherent radiation from atoms, which are excited to vibrate in the crystal lattice by a channeled charged particle, with the ordinary channeling radiation is considered. It is shown that the coherent radiation from a chain of oscillating atoms forms a resonance peak on the tail of radiation emitted by the channeled particle

  7. Analysis of plasma channels in mm-scale plasmas formed by high intensity laser beams

    International Nuclear Information System (INIS)

    Murakami, R; Habara, H; Iwawaki, T; Uematsu, Y; Tanaka, K A; Ivancic, S; Anderson, K; Haberberger, D; Stoeckl, C; Theobald, W; Sakagami, H

    2016-01-01

    A plasma channel created by a high intensity infrared laser beam was observed in a long scale-length plasma (L ∼ 240 μm) with the angular filter refractometry technique, which indicated a stable channel formation up to the critical density. We analyzed the observed plasma channel using a rigorous ray-tracing technique, which provides a deep understanding of the evolution of the channel formation. (paper)

  8. THE IMPACT OF EXTRUSION ON THE BIOGAS AND BIOMETHANE YIELD OF PLANT SUBSTRATES

    Directory of Open Access Journals (Sweden)

    Krzysztof Pilarski

    2016-09-01

    Full Text Available The objective of the present work was to determine the effect of pretreatment by extrusion on the biogas and biomethane yield of lignocellulosic substrates such as maize silage and maize straw silage. The biogas yields of the substrates before and after treatment were compared. Moreover, energy efficiency of pretreatment by extrusion was analyzed in order to assess the applicability of the process in an agricultural biogas plant. Extrusion tests were carried out in a short single-screw extruder KZM-2 in which the length-to-diameter ratio of the screw was 6:1 and rotational speed was 200 rpm. The biogas yield tests of the plant substrates after extrusion were carried out in a laboratory scale, using 15 biofermenters operated in a periodic manner, at a constant temperature of 39°C (mesophilic digestion and controlled pH conditions. The gas-emission analysis was performed using a certified gas analyzer from Geotech GA5000. Pretreatment by extrusion was observed to improve the quantity of methane generated: in terms of fresh matter for maize silage subjected to extrusion, the methane yield was 16.48% higher than that of the non-extruded silage. On the other hand, maize straw silage after extrusion gave 35.30% more methane than did the same, non-extruded, material. Differences in yields relative to dry organic matter are also described in this paper. Taking into account the amount of energy that is spent on pretreatment and the generated amount of methane, the energy balance for the process gives an idea of the economics of the operation. For maize silage, energy efficiency was lower by 13.21% (-553.2 kWh/Mg, in contrast to maize straw silage, where the increase in energy was 33.49% (678.4 kWh/Mg. The obtained results indicate that more studies on the pretreatment and digestion of maize silage are required in order to improve the efficiency of its use for making biogas. To fully utilize its potential, it is necessary to know thoroughly the effect of

  9. Seafloor classification of the mound and channel provinces of the Porcupine Seabight: An application of the multibeam angular backscatter data

    Digital Repository Service at National Institute of Oceanography (India)

    Beyer, A.; Chakraborty, B.; Schenke, H.W.

    In this study multibeam angular backscatter data acquired in the eastern slope of the Porcupine Seabight are analysed. Processing of the angular backscatter data using the ‘NRGCOR’ software was made for 29 locations comprising different geological...

  10. Study on lead extrusion damper as a seismic support

    International Nuclear Information System (INIS)

    Nomura, T.; Kojima, N.; Fujita, K.; Ito, T.

    1989-01-01

    The fundamental characteristics of two types of lead extrusion dampers (cylinder type, rotary type) for use as the nuclear power plant piping support of the elasto-plastic of damper are clarified. As a result, these lead extrusion dampers are found to have the following dynamic characteristics: hysteresis loop is both rectangular shape and bi-linear shape; maximum reaction force is independent of velocity and frequency but it increases as displacement exceeds the specified value; and the dissipated energy is very large and is independent of velocity, frequency and initial displacement (i.e., thermal expansion of pipings) in the range of test

  11. Analysis of Material Flow in Screw Extrusion of Aluminum

    International Nuclear Information System (INIS)

    Haugen, Bjoern; Oernskar, Magnus; Welo, Torgeir; Wideroee, Fredrik

    2010-01-01

    Screw extrusion of aluminum is a new process for production of aluminum profiles. The commercial potential could be large. Little experimental and numerical work has been done with respect to this process.The material flow of hot aluminum in a screw extruder has been analyzed using finite element formulations for the non-Newtonian Navier-Stokes equations. Aluminum material properties are modeled using the Zener-Holloman material model. Effects of stick-slip conditions are investigated with respect to pressure build up and mixing quality of the extrusion process.The numerical results are compared with physical experiments using an experimental screw extruder.

  12. Angular and polarization trails from effective interactions of Majorana neutrinos at the LHeC

    Science.gov (United States)

    Duarte, Lucía; Zapata, Gabriel; Sampayo, Oscar A.

    2018-05-01

    We study the possibility of the LHeC facility to disentangle different new physics contributions to the production of heavy sterile Majorana neutrinos in the lepton number violating channel e-p→ lj+ + 3 jets (l_j≡e ,μ ). This is done investigating the angular and polarization trails of effective operators with distinct Dirac-Lorentz structure contributing to the Majorana neutrino production, which parameterize new physics from a higher energy scale. We study an asymmetry in the angular distribution of the final anti-lepton and the initial electron polarization effect on the number of signal events produced by the vectorial and scalar effective interactions, finding both analyses could well separate their contributions.

  13. Optical Angular Momentum

    International Nuclear Information System (INIS)

    Arimondo, Ennio

    2004-01-01

    For many years the Institute of Physics has published books on hot topics based on a collection of reprints from different journals, including some remarks by the editors of each volume. The book on Optical Angular Momentum, edited by L Allen, S M Barnett and M J Padgett, is a recent addition to the series. It reproduces forty four papers originally published in different journals and in a few cases it provides direct access to works not easily accessible to a web navigator. The collection covers nearly a hundred years of progress in physics, starting from an historic 1909 paper by Poynting, and ending with a 2002 paper by Padgett, Barnett and coworkers on the measurement of the orbital angular momentum of a single photon. The field of optical angular momentum has expanded greatly, creating an interdisciplinary attraction for researchers operating in quantum optics, atomic physics, solid state physics, biophysics and quantum information theory. The development of laser optics, especially the control of single mode sources, has made possible the specific design of optical radiation modes with a high degree of control on the light angular momentum. The editors of this book are important figures in the field of angular momentum, having contributed to key progress in the area. L Allen published an historical paper in 1999, he and M J Padgett (together with M Babiker) produced few years ago a long review article which is today still the most complete basic introduction to the angular momentum of light, while S M Barnett has contributed several high quality papers to the progress of this area of physics. The editors' choice provides an excellent overview to all readers, with papers classified into eight different topics, covering the basic principles of the light and spin and orbital angular momentum, the laboratory tools for creating laser beams carrying orbital angular momentum, the optical forces and torques created by laser beams carrying angular momentum on

  14. An osteophyte in the tibial plateau is a risk factor for allograft extrusion after meniscus allograft transplantation.

    Science.gov (United States)

    Jeon, Byeongsam; Kim, Jong-Min; Kim, Jong-Min; Lee, Chang-Rack; Kim, Kyung-Ah; Bin, Seong-Il

    2015-05-01

    Osteophytes can be observed on the tibial plateau during meniscus allograft transplantation (MAT). However, no studies to date have evaluated the effect of these osteophytes on meniscus allograft extrusion. Osteophyte excision in the tibial plateau could reduce extrusion of the transplanted meniscus and improve short-term clinical outcomes with meniscus allograft transplantation. Cohort study; Level of evidence, 3. Between October 2004 and July 2012, a total of 323 patients underwent MAT at a single institution. Of these, 88 patients had a peripheral osteophyte in their tibial plateau, and they were enrolled in the study retrospectively. The mean age of the patients was 35.3 years (range, 15-56 years); there were 57 male and 31 female patients. Forty-four patients underwent osteophyte excision concomitantly with MAT and 44 patients underwent MAT only. The 2 groups showed no difference in terms of age, body mass index, time after meniscectomy, and preoperative knee scores. A medial meniscus allograft was transplanted in 13 cases (15%) and a lateral meniscus in 75 (85%). The absolute extrusion and relative percentage of extrusion were measured to evaluate allograft extrusion 12 months after MAT. The modified Lysholm scoring system and the Hospital for Special Surgery score at 2 years after MAT were used to evaluate clinical outcomes. The mean absolute extrusions at 1 year postoperatively in the excision and nonexcision groups were 3.5±1.5 and 5.5±1.6 mm, respectively. The mean relative percentages of extrusion were 34.1%±15.9% and 54.7%±20.7%, respectively. The rates of allograft extrusion (>3 mm) were 28 of 44 (63.6%) and 41 of 44 (93.2%) in the excision and nonexcision groups, respectively. The intergroup differences in absolute extrusion, relative percentage of extrusion, and rate of allograft extrusion were statistically significant (P<.001 for all 3 parameters). There were no significant differences in the clinical outcomes (modified Lysholm or Hospital of

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

    Science.gov (United States)

    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.

  16. Reduction of Fumonisin Toxicity by Extrusion and Nixtamalization (Alkaline Cooking).

    Science.gov (United States)

    Voss, Kenneth; Ryu, Dojin; Jackson, Lauren; Riley, Ronald; Gelineau-van Waes, Janee

    2017-08-23

    Fumonisins are mycotoxins found in corn. They are toxic to animals and cause cancer in rodents and neural tube defects in LM/Bc mice. Reducing their concentrations in corn-based foods is therefore desirable. Chemical analysis or in vitro bioassays of food extracts might not detect toxic fumonisin reaction products that are unknown or unextractable from food matrices, thus potentially underestimating in vivo toxicity. The effectiveness of two common cooking methods, extrusion and nixtamalization (alkaline cooking), to reduce the toxicity of fumonisin-contaminated corn grits (extrusion) and whole kernel corn (nixtamalization) was shown by means of rat feeding bioassays using fumonisin-specific kidney effects as indicators of potential toxicity. A third bioassay showed that in contrast to fumonisin B 1 (FB 1 ), hydrolyzed fumonisin B 1 (HFB 1 ; formed from FB 1 during nixtamalization) did not cause neural tube defects in LM/Bc mice. The findings indicate that extrusion and nixtamalization reduce the potential toxicity of FB 1 -contaminated corn.

  17. Mathematical model of a current of two plastic environments in the forming channel extruders at coextrusion

    Directory of Open Access Journals (Sweden)

    V. N. Vasilenko

    2012-01-01

    Full Text Available On the basis of the classical equations of an isothermal pressure head current of two rheology the various not mixing up viscou- plastic environments in the cylindrical channel, Ostvald-de-Vil submitting to the law, the model of a current of two viscous-plastic environments in the moulding channel extruder is synthesised at co-extrusion on which basis the technique of a choice of diameter of a dosing out branch pipe on the demanded value of the ratio of volume expenditures of two viscous-plastic environments (extrudat and stuffings is offered.

  18. Inductive ingot heating for extrusion press applications; Induktive Bolzenerwaermung fuer Strangpressanwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Beer, Stefan [I.A.S. Induktions-Anlagen + Service GmbH und Co. KG, Iserlohn (Germany)

    2013-03-15

    Inductive heating of large-format aluminium ingots on modern extrusion press lines generates significant process-engineering benefits. In addition, the proportion of special alloys processed is continuously increasing, accompanied simultaneously by ever smaller production batches, both of which are factors necessitating improvement of and greater flexibility in process-cycle control. This report examines a system concept recently commissioned on one of the world's largest aluminium extrusion presses. (orig.)

  19. FEM simulation of friction testing method based on combined forward rod-backward can extrusion

    DEFF Research Database (Denmark)

    Nakamura, T; Bay, Niels; Zhang, Z. L

    1997-01-01

    A new friction testing method by combined forward rod-backward can extrusion is proposed in order to evaluate frictional characteristics of lubricants in forging processes. By this method the friction coefficient mu and the friction factor m can be estimated along the container wall and the conical...... curves are obtained by rigid-plastic FEM simulations in a combined forward rod-backward can extrusion process for a reduction in area R-b = 25, 50 and 70 percent in the backward can extrusion. It is confirmed that the friction factor m(p) on the punch nose in the backward cart extrusion has almost...... in a mechanical press with aluminium alloy A6061 as the workpiece material and different kinds of lubricants. They confirm the analysis resulting in reasonable values for the friction coefficient and the friction factor....

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

    Science.gov (United States)

    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

  1. Wealth of information derivable from Evaporation Residue (ER) angular momentum distributions

    International Nuclear Information System (INIS)

    Madhavan, N.

    2016-01-01

    Understanding fusion-fission dynamics is possible by studying the fission process, or, alternatively, by studying the complementary fusion-evaporation process. Though the latter method is difficult to implement, requiring sophisticated recoil separators/spectrometers for selecting the ERs in the direction of the primary beam, it provides more clarity with better accuracy and is indispensible for probing the pre-saddle region in heavy nuclei. Super Heavy Element (SHE) search crucially depends on understanding the fusion-fission process, the choice of entrance channel and excitation energy of the Compound Nucleus (CN), ER cross-section and, more importantly, the angular momenta populated in ERs which survive fission. The measurement of ER angular momentum distributions, through coincidence technique involving large gamma multiplicity detector array and recoil separator, throws up a wealth of information such as, nuclear viscosity effects, limits of stability of ERs, shape changes at high spins, snapshot of frozen set of barriers using a single-shot experiment and indirect information about onset of quasi-fission processes. There is a paucity of experimental data with regard to angular momentum distributions in heavy nuclei due to experimental constraints. In this talk, the variety of information which could be derived through experimental ER angular momentum distributions will be elaborated with examples from work carried out at IUAC using advanced experimental facilities. (author)

  2. Quantum effects for particles channeling in a bent crystal

    Energy Technology Data Exchange (ETDEWEB)

    Feranchuk, Ilya, E-mail: iferanchuk@gmail.com [Atomic Molecular and Optical Physics Research Group, Ton Duc Thang University, 19 Nguyen Huu Tho Str., Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, 19 Nguyen Huu Tho Str., Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Belarusian State University, 4 Nezavisimosty Ave., 220030 Minsk (Belarus); San, Nguyen Quang [Belarusian State University, 4 Nezavisimosty Ave., 220030 Minsk (Belarus)

    2016-09-15

    Quantum mechanical theory for channeling of the relativistic charged particles in the bent crystals is considered in the paper. Quantum effects of under-barrier tunneling are essential when the radius of the curvature is closed to its critical value. In this case the wave functions of the quasi-stationary states corresponding to the particles captured in a channel are presented in the analytical form. The efficiency of channeling of the particles and their angular distribution at the exit crystal surface are calculated. Characteristic experimental parameters for observation the quantum effects are estimated.

  3. Hydrodynamic modelling of hydrostatic magnesium extrusion

    NARCIS (Netherlands)

    Moodij, Ellen; de Rooij, Matthias B.; Schipper, Dirk J.

    2006-01-01

    Wilson’s hydrodynamic model of the hydrostatic extrusion process is extended to meet the geometry found on residual billets. The transition from inlet to work zone of the process is not considered sharp as in the model of Wilson but as a rounded edge, modelled by a parabolic function. It is shown

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

    Science.gov (United States)

    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.

  5. Characterisation of the wall-slip during extrusion of heavy-clay products

    Science.gov (United States)

    Kocserha, I.; Gömze, A. L.; Kulkov, S.; Kalatur, E.; Buyakova, S. P.; Géber, R.; Buzimov, A. Y.

    2017-01-01

    During extrusion through the extrusion die, heavy-clay compounds are usually show plug flow with extensive slip at the wall of the die. In this study, the viscosity and the thickness of the slip layer were investigated. For the examination a brick-clay from Malyi (Hungary) deposit was applied as a raw material. The clay was characterised by XRPD, BET, SEM and granulometry. As the slip layer consists of suspension of the fine clay fraction so the clay minerals content of the clay (dviscosity of suspension with different water content was measured by means of rotational viscosimeter. The thickness of the slip layer was calculated from the measured viscosity and other data obtained from an earlier study with capillary rheometer. The calculated thickness value showed a tendency to reach a limit value by increasing the extrusion speed.

  6. Further development of a facility for channeling studies: application to lattice location

    International Nuclear Information System (INIS)

    Lopes, D.R.

    1984-08-01

    Equipment modifications at the Lawrence Berkeley Laboratory (LBL) Rutherford backscattering facility, including the addition of a high precision goniometer, have been made to enhance the performance of channeling experiments. The angular divergence of the alpha particle beam was also reduced to 0 by improving the collimation. To demonstrate improved channeling capability angular scans were performed about the [100], [110], and [111] axial channels of a 3400 A (100) silicon membrane. Both the minimum yield, chi/sub min/, and the critical angle, psi/sub 1/2/, were consistent with accepted values. A preliminary investigation of the lattice location of cobalt on the (100) silicon surface was undertaken. Approximately 4.5 x 10 15 Co atoms/cm 2 were electron beam deposited on a 3900 A, HF etched silicon membrane in a system using oilless pumps. Preliminary channeling data taken approximately one month later indicated a preferred site for approximately 16% of the cobalt atoms. Channeling data obtained six months later with the new goniometer showed no evidence for a preferred site. Room temperature oxidation between experiments was observed and is thought to have affected the location of the cobalt atoms. 33 references, 15 figures

  7. Multi-channel coherent perfect absorbers

    KAUST Repository

    Bai, Ping

    2016-05-18

    The absorption efficiency of a coherent perfect absorber usually depends on the phase coherence of the incident waves on the surfaces. Here, we present a scheme to create a multi-channel coherent perfect absorber in which the constraint of phase coherence is loosened. The scheme has a multi-layer structure such that incident waves in different channels with different angular momenta can be simultaneously and perfectly absorbed. This absorber is robust in achieving high absorption efficiency even if the incident waves become "incoherent" and possess "random" wave fronts. Our work demonstrates a unique approach to designing highly efficient metamaterial absorbers. © CopyrightEPLA, 2016.

  8. Multi-channel coherent perfect absorbers

    KAUST Repository

    Bai, Ping; Wu, Ying; Lai, Yun

    2016-01-01

    The absorption efficiency of a coherent perfect absorber usually depends on the phase coherence of the incident waves on the surfaces. Here, we present a scheme to create a multi-channel coherent perfect absorber in which the constraint of phase coherence is loosened. The scheme has a multi-layer structure such that incident waves in different channels with different angular momenta can be simultaneously and perfectly absorbed. This absorber is robust in achieving high absorption efficiency even if the incident waves become "incoherent" and possess "random" wave fronts. Our work demonstrates a unique approach to designing highly efficient metamaterial absorbers. © CopyrightEPLA, 2016.

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

    Science.gov (United States)

    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.

  10. Experimental and finite element analyses of plastic deformation behavior in vortex extrusion

    International Nuclear Information System (INIS)

    Shahbaz, M.; Pardis, N.; Kim, J.G.; Ebrahimi, R.; Kim, H.S.

    2016-01-01

    Vortex extrusion (VE) is a single pass severe plastic deformation (SPD) technique which can impose high strain values with almost uniform distribution within cross section of the processed material. This technique needs no additional facilities for installation on any conventional extrusion equipment. In this study the deformation behavior of material during VE is investigated and the results are compared with those of conventional extrusion (CE). These investigations include finite element analysis, visioplasticity, and microstructural characterization of the processed samples. The results indicate that the VE process can accumulate a higher strain value by applying an additional torsional deformation. The role of this additional deformation mode on the microstructural evolution of the VE sample is discussed and compared with the results obtained on the CE samples.

  11. Extrusion Process by Finite Volume Method Using OpenFoam Software

    International Nuclear Information System (INIS)

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

    2011-01-01

    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.

  12. 75 FR 51243 - Aluminum Extrusions from the People's Republic of China: Postponement of Preliminary...

    Science.gov (United States)

    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...

  13. Experimental characterization of a 400  Gbit/s orbital angular momentum multiplexed free-space optical link over 120 m

    OpenAIRE

    Ren, Yongxiong; Wang, Zhe; Liao, Peicheng; Li, Long; Xie, Guodong; Huang, Hao; Zhao, Zhe; Yan, Yan; Ahmed, Nisar; Willner, Asher; Lavery, Martin P.J.; Ashrafi, Nima; Ashrafi, Solyman; Bock, Robert; Tur, Moshe

    2016-01-01

    We experimentally demonstrate and characterize the\\ud performance of a 400-Gbit/s orbital angular momentum\\ud (OAM) multiplexed free-space optical link over 120-\\ud meters on the roof of a building. Four OAM beams, each\\ud carrying a 100-Gbit/s QPSK channel are multiplexed and\\ud transmitted. We investigate the influence of channel\\ud impairments on the received power, inter-modal\\ud crosstalk among channels, and system power penalties.\\ud Without laser tracking and compensation systems, the\\...

  14. Dimensional accuracy of aluminium extrusions in mechanical calibration

    Science.gov (United States)

    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.

  15. Microstructure and Mechanical Properties of Bulk Nanostructured Cu-Ta Alloys Consolidated by Equal Channel Angular Extrusion

    Science.gov (United States)

    2014-07-01

    5,9], W [16], Zr [17] and Nb [18]. These systems have shown moderate to extraordinarily high microstructural stability at elevated temperatures...cans were then either serial sectioned for shear punch testing or cut into compression samples using wire electric discharge machining. Through SEM...to resist deformation, but do not necessarily alter the dislocation mechanism operating during plastic deformation. There are a number of challenges

  16. Solution of the Fokker-Planck equation for axially-channeled relativistic electrons

    International Nuclear Information System (INIS)

    Muralev, V.A.; Telegin, V.I.

    1981-01-01

    A method of the two dimensional kinetic equation of the Fokker-Planck type for axially-channeled electrons is proposed. This equation has been obtained recently by Beloshitsky and Kumakhov to describe the diffusion of channeling negative particles over the transverse energy and angular momentum. The results of computation of the dechanneling function of 1 GeV electrons in tungsten are presented. (author)

  17. Mechanical properties of ultra-fine grained structure formed in Al-Li alloys

    International Nuclear Information System (INIS)

    Adamczyk-Cieslak, B.; Lewandowska, M.; Mizera, J.; Kurzydlowski, K.J.

    2004-01-01

    This paper describes the mechanical properties (microhardness, yield stress) of two model Al-Li alloys by the Equal-Channel-Angular-Extrusion (ECAE) process. The applied ECAE process reduced the grain size from an initial value of ∼300 μm to a value of ∼0.7 μm leading to profound increase of plastic flow resistance. Such an increase is related to the grain size refinement and strengthening due to Li atoms in solid solution. Microhardness data confirm the Hall - Petch relation for grain sizes not available so far in Al-Li alloys. (author)

  18. 77 FR 74466 - Aluminum Extrusions From the People's Republic of China: Notice of Court Decision Not in Harmony...

    Science.gov (United States)

    2012-12-14

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-968] Aluminum Extrusions From the... countervailing duty (CVD) investigation of aluminum extrusions from the People's Republic of China (PRC) \\1... Aluminum Extrusions From the People's Republic of China: Final Affirmative Countervailing Duty...

  19. Friction phenomena in hydrostatic extrusion of magnesium

    NARCIS (Netherlands)

    Moodij, Ellen

    2014-01-01

    When magnesium is hydrostatically extruded an inconsistent and sometimes bad surface quality is encountered. In hydrostatic extrusion the billet is surrounded by a lubricant, usually castor oil. The required pressure to deform the material is applied onto this lubricant and not directly to the

  20. Debris extrusion by glide-path establishing endodontic instruments with different geometries

    Directory of Open Access Journals (Sweden)

    Jung-Hong Ha

    2016-06-01

    Conclusion: Creating the glide-path using nickel-titanium rotary files produced lower amounts of debris extrusion than using manual stainless-steel files. The progressive taper design of ProGlider, the center-off cross-section of One G, and the alternative-pitch design of ScoutRace may have increased the efficiencies of debris removal with minimal extrusion during glide-path preparation. Glide-path preparation using NiTi rotary files have better clinical efficiency than the manual stainless-steel file.

  1. Concept Feasibility Report for Using Co-Extrusion to Bond Metals to Complex Shapes of U-10Mo

    Energy Technology Data Exchange (ETDEWEB)

    Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Paxton, Dean M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smith, Mark T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Soulami, Ayoub [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Joshi, Vineet V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burkes, Douglas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-12-01

    In support of the Convert Program of the U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA) Global Threat Reduction Initiative (GTRI), Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum (U-10Mo) alloy plate fuel for the U.S. high-performance research reactors (USHPRR). This report documents the results of PNNL’s efforts to develop the extrusion process for this concept. The approach to the development of a co-extruded complex-shaped fuel has been described and an extrusion of DU-10Mo was made. The initial findings suggest that given the extrusion forces required for processing U-10Mo, the co-extrusion process can meet the production demands of the USHPRR fuel and may be a viable production method. The development activity is in the early stages and has just begun to identify technical challenges to address details such as dimensional tolerances and shape control. New extrusion dies and roll groove profiles have been developed and will be assessed by extrusion and rolling of U-10Mo during the next fiscal year. Progress on the development and demonstration of the co-extrusion process for flat and shaped fuel is reported in this document

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

    Science.gov (United States)

    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.

  3. Recent Advances in Extrusion-Based 3D Printing for Biomedical Applications.

    Science.gov (United States)

    Placone, Jesse K; Engler, Adam J

    2018-04-01

    Additive manufacturing, or 3D printing, has become significantly more commonplace in tissue engineering over the past decade, as a variety of new printing materials have been developed. In extrusion-based printing, materials are used for applications that range from cell free printing to cell-laden bioinks that mimic natural tissues. Beyond single tissue applications, multi-material extrusion based printing has recently been developed to manufacture scaffolds that mimic tissue interfaces. Despite these advances, some material limitations prevent wider adoption of the extrusion-based 3D printers currently available. This progress report provides an overview of this commonly used printing strategy, as well as insight into how this technique can be improved. As such, it is hoped that the prospective report guides the inclusion of more rigorous material characterization prior to printing, thereby facilitating cross-platform utilization and reproducibility. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Forward impact extrusion of surface textured steel blanks using coated tooling

    Science.gov (United States)

    Hild, Rafael; Feuerhack, Andreas; Trauth, Daniel; Arghavani, Mostafa; Kruppe, Nathan C.; Brögelmann, Tobias; Bobzin, Kirsten; Klocke, Fritz

    2017-10-01

    A method to enable dry metal forming by the means of a self-lubricating coating and surface textures was researched using an innovative Pin-On-Cylinder-Tribometer. The experimental analysis was complemented by a numerical model of the complex contact conditions between coated tools and the surface textured specimen at the micro-level. Based on the results, the explanation of the tribological interactions between surface textured specimens and the tool in dry full forward extrusion is the objective of this work. Therefore, experimental dry extrusion tests were performed using a tool system. The extruded specimens were evaluated regarding their geometry as well as by the required punch force. Thereby, the effectiveness and the feasibility of dry metal forming on the example of full forward extrusion was evaluated. Thus, one more step towards the technical realization of dry metal forming of low alloy steels under industrial conditions was realized.

  5. Angular correlation methods

    International Nuclear Information System (INIS)

    Ferguson, A.J.

    1974-01-01

    An outline of the theory of angular correlations is presented, and the difference between the modern density matrix method and the traditional wave function method is stressed. Comments are offered on particular angular correlation theoretical techniques. A brief discussion is given of recent studies of gamma ray angular correlations of reaction products recoiling with high velocity into vacuum. Two methods for optimization to obtain the most accurate expansion coefficients of the correlation are discussed. (1 figure, 53 references) (U.S.)

  6. Observation of diffraction effects in positron channeling

    International Nuclear Information System (INIS)

    Palathingal, J.C.; Peng, J.P.; Lynn, K.G.; Wu, X.Y.; Schultz, P.J.

    1994-01-01

    An experimental investigation of positron channeling was made with a high-angular resolution apparatus, employing positrons of kinetic energy 1 MeV, derived from the Brookhaven National Laboratory Dynamitron. The pattern of transmission through a Si (100) single crystal of thickness 0.245 μm was investigated for a number of major planes. The authors have observed for the first time, in excellent detail, the fine structure of the channeling pattern expected to arise from the particle diffraction effects, theoretically explainable in terms of the quantum-mechanical many-beam calculations

  7. Investigation of the process energy demand in polymer extrusion: A brief review and an experimental study

    International Nuclear Information System (INIS)

    Abeykoon, Chamil; Kelly, Adrian L.; Brown, Elaine C.; Vera-Sorroche, Javier; Coates, Phil D.; Harkin-Jones, Eileen; Howell, Ken B.; Deng, Jing; Li, Kang; Price, Mark

    2014-01-01

    Highlights: • Energy consumption and losses in polymer extrusion are discussed. • This compares energy consumption in polymer extrusion at different conditions. • The role of power factor on energy efficiency in polymer extrusion is explored. • Empirical models on extruder energy consumption are provided. • Computer modelling of energy consumption of polymer extrusion is performed. - Abstract: Extrusion is one of the fundamental production methods in the polymer processing industry and is used in the production of a large number of commodities in a diverse industrial sector. Being an energy intensive production method, process energy efficiency is one of the major concerns and the selection of the most energy efficient processing conditions is a key to reducing operating costs. Usually, extruders consume energy through the drive motor, barrel heaters, cooling fans, cooling water pumps, gear pumps, etc. Typically the drive motor is the largest energy consuming device in an extruder while barrel/die heaters are responsible for the second largest energy demand. This study is focused on investigating the total energy demand of an extrusion plant under various processing conditions while identifying ways to optimise the energy efficiency. Initially, a review was carried out on the monitoring and modelling of the energy consumption in polymer extrusion. Also, the power factor, energy demand and losses of a typical extrusion plant were discussed in detail. The mass throughput, total energy consumption and power factor of an extruder were experimentally observed over different processing conditions and the total extruder energy demand was modelled empirically and also using a commercially available extrusion simulation software. The experimental results show that extruder energy demand is heavily coupled between the machine, material and process parameters. The total power predicted by the simulation software exhibits a lagging offset compared with the

  8. Study of dissociative collisions of hydrogen-line ions by mean of angular and energy distributions

    International Nuclear Information System (INIS)

    Martinez, H.; Urquijo, J. de; Cisneros, C.; Alvarez, J.

    1988-01-01

    Angular and energy distribution of fragments produced in a collision, employed in conjunction with the 'step-model' that means excitation and binary dissociation, are used to determine the binding energy of H 3 (D 3 ) and HD + 2 and also to identify the principal channels in the dissociation processes. (A.C.A.S.) [pt

  9. Shuttle Primary Reaction Control Subsystem Thruster Fuel Valve Pilot Seal Extrusion: A Failure Correlation

    Science.gov (United States)

    Waller, Jess; Saulsberry, Regor L.

    2003-01-01

    Pilot operated valves (POVs) are used to control the flow of hypergolic propellants monomethylhydrazine (fuel) and nitrogen tetroxide (oxidizer) to the Shuttle orbiter Primary Reaction Control Subsystem (PRCS) thrusters. The POV incorporates a two-stage design: a solenoid-actuated pilot stage, which in turn controls a pressure-actuated main stage. Isolation of propellant supply from the thruster chamber is accomplished in part by a captive polytetrafluoroethylene (PTFE) pilot seal retained inside a Custom 455.1 stainless steel cavity. Extrusion of the pilot seal restricts the flow of fuel around the pilot poppet, thus impeding or preventing the main valve stage from opening. It can also prevent the main stage from staying open with adequate force margin, particularly if there is gas in the main stage actuation cavity. During thruster operation on-orbit, fuel valve pilot seal extrusion is commonly indicated by low or erratic chamber pressure or failure of the thruster to fire upon command (Fail-Off). During ground turnaround, pilot seal extrusion is commonly indicated by slow gaseous nitrogen (GN2) main valve opening times (greater than 38 ms) or slow water main valve opening response times (greater than 33 ms). Poppet lift tests and visual inspection can also detect pilot seal extrusion during ground servicing; however, direct metrology on the pilot seat assembly provides the most quantitative and accurate means of identifying extrusion. Minimizing PRCS fuel valve pilot seal extrusion has become an important issue in the effort to improve PRCS reliability and reduce associated life cycle costs.

  10. Physical and mathematical modelling of extrusion processes

    DEFF Research Database (Denmark)

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

    2000-01-01

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

  11. Extrusion of ECC: Recent Developments and Applications

    DEFF Research Database (Denmark)

    Stang, Henrik; Fredslund-Hansen, Helge; Puclin, Tony

    2008-01-01

    process. Extrusion of cementitious (fiber reinforced) materials has proven particularly difficult due to the high inter-particle friction combined with the disastrous effect of static zones in the flow pattern, and to the ease of phase migration or separation. In order to deal with these conflicting...

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

    Science.gov (United States)

    Hengsawas Surasarang, Soraya; Keen, Justin M; Huang, Siyuan; Zhang, Feng; McGinity, James W; Williams, Robert O

    2017-05-01

    The purpose of this study was to enhance the dissolution properties of albendazole (ABZ) by the use of amorphous solid dispersions. Phase diagrams of ABZ-polymer binary mixtures generated from Flory-Huggins theory were used to assess miscibility and processability. Forced degradation studies showed that ABZ degraded upon exposure to hydrogen peroxide and 1 N NaOH at 80 °C for 5 min, and the degradants were albendazole sulfoxide (ABZSX), and ABZ impurity A, respectively. ABZ was chemically stable following exposure to 1 N HCl at 80 °C for one hour. Thermal degradation profiles show that ABZ, with and without Kollidon ® VA 64, degraded at 180 °C and 140 °C, respectively, which indicated that ABZ could likely be processed by thermal processing. Following hot melt extrusion, ABZ degraded up to 97.4%, while the amorphous ABZ solid dispersion was successfully prepared by spray drying. Spray-dried ABZ formulations using various types of acids (methanesulfonic acid, sulfuric acid and hydrochloric acid) and polymers (Kollidon ® VA 64, Soluplus ® and Eudragit ® E PO) were studied. The spray-dried ABZ with methanesulfonic acid and Kollidon ® VA 64 substantially improved non-sink dissolution in acidic media as compared to bulk ABZ (8-fold), physical mixture of ABZ:Kollidon ® VA 64 (5.6-fold) and ABZ mesylate salt (1.6-fold). No degradation was observed in the spray-dried product for up to six months and less than 5% after one-year storage. In conclusion, amorphous ABZ solid dispersions in combination with an acid and polymer can be prepared by spray drying to enhance dissolution and shelf-stability, whereas those made by melt extrusion are degraded.

  13. Plasticized chitosan/polyolefin films produced by extrusion.

    Science.gov (United States)

    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.

  14. Spatial correlation in 3D MIMO channels using fourier coefficients of power spectrums

    KAUST Repository

    Nadeem, Qurrat-Ul-Ain

    2015-03-01

    In this paper, an exact closed-form expression for the Spatial Correlation Function (SCF) is derived for the standardized three-dimensional (3D) multiple-input multiple-output (MIMO) channel. This novel SCF is developed for a uniform linear array of antennas with non-isotropic antenna patterns. The proposed method resorts to the spherical harmonic expansion (SHE) of plane waves and the trigonometric expansion of Legendre and associated Legendre polynomials to obtain a closed-form expression for the SCF for arbitrary angular distributions and antenna patterns. The resulting expression depends on the underlying angular distributions and antenna patterns through the Fourier Series (FS) coefficients of power azimuth and elevation spectrums. The novelty of the proposed method lies in the SCF being valid for any 3D propagation environment. Numerical results validate the proposed analytical expression and study the impact of angular spreads on the correlation. The derived SCF will help evaluate the performance of correlated 3D MIMO channels in the future. © 2015 IEEE.

  15. Angular distributions of relativistic electrons under channeling in half-wavelength crystal and corresponding radiation

    International Nuclear Information System (INIS)

    Takabayashi, Y.; Bagrov, V.G.; Bogdanov, O.V.; Pivovarov, Yu.L.; Tukhfatullin, T.A.

    2015-01-01

    New experiments on channeling of 255 MeV electrons in a half-wavelength crystals (HWC) were performed at SAGA Light Source facilities. The simulations of trajectories for (2 2 0) and (1 1 1) planar channeling in Si were performed using the computer code BCM-1.0. Comparison of experimental and theoretical results shows a good agreement. The results of calculations of spectral distribution of radiation in forward direction (θ = 0°) from 255 MeV electrons at (2 2 0) channeling in HWC silicon are presented. Qualitative comparison with radiation spectrum from an electron moving in an arc is performed

  16. Back extrusion of vocadlo-type fluids

    Czech Academy of Sciences Publication Activity Database

    David, Jiří; Filip, Petr; Kharlamov, Alexander

    2013-01-01

    Roč. 23, č. 4 (2013), , 45366-1-45366-8 ISSN 1430-6395 R&D Projects: GA ČR GA103/09/2066 Institutional support: RVO:67985874 Keywords : viscosity * back extrusion * annular pumping * vocadlo model * Robertson-stiff model Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.592, year: 2013 http://www.ar.ethz.ch/TMPPDF/23840225602.368/ApplRheol_23_45366.pdf

  17. Research variations the channel of gallbladder in relation to gender

    Directory of Open Access Journals (Sweden)

    Spasojević Goran

    2014-01-01

    Full Text Available Channel of the gallbladder (DC shows the different anatomical variations, the knowledge is important in the diagnosis and particularly abdominal surgery. The aim of this study was to investigate possible gender differences in the morphology of the gallbladder channel (DC. A total sample consists of 50 anatomical liver taken from autopsy cases of both sexes (32 men and 18 women. Samples of liver were fixed in 4% formalin for 4 weeks, and then studied microdissected under scrutiny. We were working length measurement channels of the gallbladder (DC and typing of junction of the cystic (DC with the common hepatic duct (DHC. We classify anatomical junction variations DC with DHC into three types: angular, parallel and spiral type, and then performed statistical analysis of the data with respect to gender. Results: The angular type compound we found approximately at 2/3 or 64% of the samples (men-60% of women-72%, the parallel type combination of a total of 22% of the sample (men-31% of women-6% and spiral type of 14% of the samples (males-9%, women 22%. Parallel and spiral type together make up about 1/3 of the cases. The average length of DC is 3.1 cm and the variation interval of 1.7 to 6.2 cm. We found that the difference circuit between DC and DHC the angular variable (parallel junction and spiral with respect to gender there but the difference was not statistically significant (p> 0.05.

  18. Preparation and Evaluation of Pellets Using Acacia and Tragacanth by Extrusion-Spheronization

    OpenAIRE

    S. Pirmoradi; M R. Abbaspour; A. Akhgari

    2011-01-01

    Background and the purpose of the study: Extrusion-spheronization is an established technique for the production of pellets for pharmaceutical applications. In this study, the feasibility and influence of the incorporation of acacia, by itself and in combination with tragacanth, on the ability of formulations containing 2 model of drugs (ibuprofen and theophylline) to form spherical pellets by extrusion-spheronization was investigated.Material and Methods: Formulations containing different ra...

  19. Root resorption after orthodontic intrusion and extrusion:.

    NARCIS (Netherlands)

    Han, G.; Huang, S.; Hoff, J.W. Von den; Zeng, X.; Kuijpers-Jagtman, A.M.

    2005-01-01

    The aim of this investigation was to compare root resorption in the same individual after application of continuous intrusive and extrusive forces. In nine patients (mean age 15.3 years), the maxillary first premolars were randomly intruded or extruded with a continuous force of 100 cN for eight

  20. Ultrarelativistic electron and positron radiation in planar channeling

    International Nuclear Information System (INIS)

    Kalashnikov, N.P.; Olchack, A.S.

    1980-01-01

    The coherent electromagnetic radiation from channeling electrons and positrons is given by similar expression. However for the channeling positrons the close collisions are suppressed due to the fact that the positron wave function is exponentially small near the atoms of the crystal lattice. It follows that the coherent bremsstrahlung decreases for the channeling positrons. We have investigated the ultrarelativistic channeling electron and positron radiations, connected with the electromagnetic transitions from the continuum spectrum states to the quasi-bound spectrum states and between the different quasi-bound spectrum states. The radiation probabilities are calculated by using the model continuum planar potential. It is shown that the radiation from the channeling electrons is several orders of magnitude larger than the positron radiation, while the electron and positron radiation have similar characteristics such as frequency limitation and angular distribution of the radiation. (orig.)

  1. Optical angular momentum and atoms.

    Science.gov (United States)

    Franke-Arnold, Sonja

    2017-02-28

    Any coherent interaction of light and atoms needs to conserve energy, linear momentum and angular momentum. What happens to an atom's angular momentum if it encounters light that carries orbital angular momentum (OAM)? This is a particularly intriguing question as the angular momentum of atoms is quantized, incorporating the intrinsic spin angular momentum of the individual electrons as well as the OAM associated with their spatial distribution. In addition, a mechanical angular momentum can arise from the rotation of the entire atom, which for very cold atoms is also quantized. Atoms therefore allow us to probe and access the quantum properties of light's OAM, aiding our fundamental understanding of light-matter interactions, and moreover, allowing us to construct OAM-based applications, including quantum memories, frequency converters for shaped light and OAM-based sensors.This article is part of the themed issue 'Optical orbital angular momentum'. © 2017 The Author(s).

  2. Optical angular momentum and atoms

    Science.gov (United States)

    2017-01-01

    Any coherent interaction of light and atoms needs to conserve energy, linear momentum and angular momentum. What happens to an atom’s angular momentum if it encounters light that carries orbital angular momentum (OAM)? This is a particularly intriguing question as the angular momentum of atoms is quantized, incorporating the intrinsic spin angular momentum of the individual electrons as well as the OAM associated with their spatial distribution. In addition, a mechanical angular momentum can arise from the rotation of the entire atom, which for very cold atoms is also quantized. Atoms therefore allow us to probe and access the quantum properties of light’s OAM, aiding our fundamental understanding of light–matter interactions, and moreover, allowing us to construct OAM-based applications, including quantum memories, frequency converters for shaped light and OAM-based sensors. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069766

  3. Lateral extrusion of Tunisia : Contribution of Jeffara Fault (southern branch) and Petroleum Implications

    Science.gov (United States)

    Ghedhoui, R.; Deffontaines, B.; Rabia, M. C.

    2012-04-01

    Contrasting to the northward African plate motion toward Eurasia and due to its geographic position in the North African margin, since early cretaceous, Tunisia seems to be submitted to an eastward migration. The aim of this work is to study the southern branch of this inferred tectonic splay that may guide the Tunisian extrusion characterised to the east by the Mediterranean sea as a free eastern boundary. The Jeffara Fault zone (southern Tunisia), represent a case example of such deformation faced by Tunisia. Helped by the results of previous researchers (Bouaziz, 1995 ; Rabiaa, 1998 ; Touati et Rodgers, 1998 ; Sokoutis D. et al., 2000 ; Bouaziz et al., 2002 ; Jallouli et al., 2005 ; Deffontaines et al., 2008…), and new evidences developed in this study, we propose a geodynamic Tunisian east extrusion model, due to such the northern African plate migration to the Eurasian one. In this subject, structural geomorphology is undertaken herein based on both geomorphometric drainage network analysis (Deffontaines et al., 1990), the Digital Terrain Model photo-interpretation (SRTM) combined with photo-interpretation of detailed optical images (Landsat ETM+), and confirmed by field work and numerous seismic profiles at depth. All these informations were then integrated within a GIS (Geodatabase) (Deffontaines 1990 ; Deffontaines et al. 1994 ; Deffontaines, 2000 ; Slama, 2008 ; Deffontaines, 2008) and are coherent with the eastern extrusion of the Sahel block. We infer that the NW-SE Gafsa-Tozeur, which continue to the Jeffara major fault zone acting as a transtensive right lateral motion since early cretaceous is the southern branch of the Sahel block extrusion. Our structural analyses prove the presence of NW-SE right lateral en-echelon tension gashes, NW-SE aligned salt diapirs, numerous folds offsets, en-echelon folds, and so on that parallel this major NW-SE transtensive extrusion fault zone.These evidences confirm the fact that the NW-SE Jeffara faults correspond

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  6. Microstructural evolution and wear characteristics of equal channel angular pressing processed semi-solid-cast hypoeutectic aluminum alloys

    International Nuclear Information System (INIS)

    Thuong, Nguyen Van; Zuhailawati, Hussain; Seman, Anasyida Abu; Huy, Tran Duc; Dhindaw, Brij Kumar

    2015-01-01

    Highlights: • We produced aluminum feedstock for ECAP by two casting techniques: conventional and with cooling slope. • Globular α-Al phase was found in cooling slope sample compared to dendritic in the conventional. • After ECAP uniform Si particles distribution and fine α-Al were observed for cooling slope. • We observed significant improvement in wear resistance of ECAPed sample produced by cooling slope. - Abstract: This work investigated the microstructural evolution of Al–7Si–Mg alloy cast semi-solid using a cooling slope as well as conventional casting followed by equal channel angular pressing (ECAP) in a 120° die. Feed materials were prepared for ECAP by cooling slope casting and by conventional casting. The microstructure of the processed alloys extruded was observed by optical microscope and by transmission electron microscope, and their hardness and wear resistance were evaluated. After ECAP processing, the primary α-Al phase tended to be elongated while the Si particles became fragmented and more nearly globular in shape and uniform in size than in the as-cast sample. The microstructure of the cooling slope-cast ECAPed samples was more homogenous than that of the conventionally cast ECAPed sample. The α-Al phase sub-grains were refined to sub-micrometer sizes for samples cast by both methods after ECAP. The hardness of the cooling slope-cast ECAPed sample was also higher than that of the conventionally cast ECAPed sample. The wear resistance of the alloy improved after cooling slope casting and ECAP processing

  7. Equal channel angular pressing of powder processed Al6061/SiC nano metal matrix composites and study of its wear properties

    Science.gov (United States)

    Bongale, Arunkumar M.; Kumar, Satish

    2018-03-01

    Nano Metal Matrix Composites were fabricated by a novel approach by combining powder metallurgy and equal channel angular pressing (ECAP) using aluminium alloy 6061 (Al6061) as matrix phase and 2, 4 and 6 wt% of silicon carbide nanoparticles (SiCnp) as reinforcements. Alloying elements of Al6061 in their elemental form are blended together using high energy planetary ball mill and calculated wt% of SiCnp were mixed with it. Thus formed composite powder mixture is compacted in a uniaxial compaction die and then subjected to ECAP up to three passes. Density and porosity of samples were estimated using Archimedes’ principle. Pin on disc setup is used to evaluate the wear properties of the composites under different speed and loading conditions. Tests revealed that increase in wt% of SiCnp reduces the wear rate of the composites whereas increasing the load and speed increases wear rate of the composite samples. SEM micrographs of worn surfaces indicated different types of wear mechanism responsible for wear of the specimens under different testing conditions. Also, wt% of SiCnp and the number of passes through ECAP were found to increase the hardness value of the composite material.

  8. The influence of deformation path on strain characteristics of AA1050 aluminium processed by equal-channel angular pressing followed by rolling

    Energy Technology Data Exchange (ETDEWEB)

    Vega, M.C.V. [Department of Materials Engineering – Universidade Federal de São Carlos, (SP) Rod. Washington Luis km 235, 13565-905 São Carlos (Brazil); Bolmaro, R.E. [Instituto de Física Rosario (IFIR) FCEIA-UNR-CONICET, Bv. 27 de Febrero 210 bis, S2000EZP Rosario (Argentina); Ferrante, M.; Sordi, V.L. [Department of Materials Engineering – Universidade Federal de São Carlos, (SP) Rod. Washington Luis km 235, 13565-905 São Carlos (Brazil); Kliauga, A.M., E-mail: kliauga@ufscar.br [Department of Materials Engineering – Universidade Federal de São Carlos, (SP) Rod. Washington Luis km 235, 13565-905 São Carlos (Brazil)

    2015-10-14

    The present investigation reports on the microstructure evolution, texture development, the nature of the grain boundaries and the tensile and deep drawing behaviour of commercial AA1050 Al processed by Equal Channel Angular Pressing (ECAP) plus rolling. Although in terms of final mechanical strength ECAP and rolling are indistinguishable, the deformation path is substantially different, and this has important consequences on both microstructure and texture. From the spatial distribution of high angle grain boundaries (HAGB) and low angle grain boundaries (LAGB), the fine microstructure and the crystallographic texture, it was concluded that the microstructure is oriented according to the external imposed flow: a spin movement in the ECAP process, which promotes the rotation of the cells inside the original grain, followed by a sliding movement caused by the rolling, leading to grain elongation. The ECAP process is more suitable to promote a higher fraction of HAGBs, and the same time as it reduces the intensity of the bulk crystallographic texture. As a consequence an increase of the penetration depth and deformation strain, as measured by the Erichsen test, was observed in samples processed by 8 ECAP passes, characterized by low texture intensity and a high degree of dynamic recrystallization.

  9. Total yield of channeling radiation from relativistic electrons in thin Si and W crystals

    International Nuclear Information System (INIS)

    Abdrashitov, S.V.; Bogdanov, O.V.; Dabagov, S.B.; Pivovarov, Yu.L.; Tukhfatullin, T.A.

    2013-01-01

    Orientation dependences of channeling radiation total yield from relativistic 155–855 MeV electrons at both 〈1 0 0〉 axial and (1 0 0) planar channeling in thin silicon and tungsten crystals are studied by means of computer simulations. The model as well as computer code developed allows getting the quantitative results for orientation dependence of channeling radiation that can be used for crystal alignment in channeling experiments and/or for diagnostics of initial angular divergence of electron beam

  10. Management of vaginal extrusion after tension-free vaginal tape procedure for urodynamic stress incontinence.

    Science.gov (United States)

    Giri, Subhasis K; Sil, Debasri; Narasimhulu, Girish; Flood, Hugh D; Skehan, Mark; Drumm, John

    2007-06-01

    To report our experience in the management of vaginal extrusion after the tension-free vaginal tape (TVT) procedure for urodynamic stress incontinence. Five patients diagnosed with vaginal extrusion after a TVT procedure performed at our institution were identified. We reviewed the patients' records retrospectively. The interval from TVT placement to diagnosis, presenting symptoms and signs, duration of symptoms, diagnostic test findings, treatment, and postoperative results were recorded. Patients were followed up for at least 12 months. From January 2001 to June 2004, a total of 166 patients underwent the TVT procedure. Of these, 5 patients (3%) were diagnosed with isolated vaginal extrusion 4 to 40 months postoperatively. No cases of urethral or bladder erosion occurred in this series. The symptoms included vaginal discharge, pain, bleeding, and dyspareunia. The eroded margin of the vaginal mucosa was trimmed, mobilized, and closed over the tape with interrupted vertical mattress sutures in a single layer using 2-0 polyglactin 910 to avoid mucosal inversion. All patients remained symptom free without any evidence of defective healing or additional extrusion at a minimal follow-up of 12 months. Primary reclosure of the vaginal mucosa over the TVT tape is an effective first-line treatment option for vaginal extrusion without compromising continence. Patients undergoing the TVT procedure should be adequately counseled about the possibility of this complication and the available treatment options.

  11. Differential branching fraction and angular analysis of the decay $B_s^0 \\to \\phi \\mu^+\\mu^-$

    CERN Document Server

    Aaij, R; Adeva, B; Adinolfi, M; Adrover, C; Affolder, A; Ajaltouni, Z; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves Jr, A A; Amato, S; Amerio, S; Amhis, Y; Anderlini, L; Anderson, J; Andreassen, R; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Bachmann, S; Back, J J; Baesso, C; Balagura, V; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Bauer, Th; Bay, A; Beddow, J; Bedeschi, F; Bediaga, I; Belogurov, S; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bettler, M -O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Bowcock, T J V; Bowen, E; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Britsch, M; Britton, T; Brook, N H; Brown, H; Burducea, I; Bursche, A; Busetto, G; Buytaert, J; 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Easo, S; Egede, U; Egorychev, V; Eidelman, S; van Eijk, D; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; El Rifai, I; Elsasser, Ch; Elsby, D; Falabella, A; Färber, C; Fardell, G; Farinelli, C; Farry, S; Fave, V; Ferguson, D; Fernandez Albor, V; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fiore, M; Fitzpatrick, C; Fontana, M; Fontanelli, F; Forty, R; Francisco, O; Frank, M; Frei, C; Frosini, M; Furcas, S; Furfaro, E; Gallas Torreira, A; Galli, D; Gandelman, M; Gandini, P; Gao, Y; Garofoli, J; Garosi, P; Garra Tico, J; Garrido, L; Gaspar, C; Gauld, R; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gibson, V; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gordon, H; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Griffith, P; Grünberg, O; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hampson, T; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Hartmann, T; He, J; Heijne, V; Hennessy, K; Henrard, P; Hernando Morata, J A; van Herwijnen, E; Hicheur, A; Hicks, E; Hill, D; Hoballah, M; Holtrop, M; Hombach, C; Hopchev, P; Hulsbergen, W; Hunt, P; Huse, T; Hussain, N; Hutchcroft, D; Hynds, D; Iakovenko, V; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jans, E; Jaton, P; Jawahery, A; Jing, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Kaballo, M; Kandybei, S; Karacson, M; Karbach, T M; Kenyon, I R; Kerzel, U; Ketel, T; Keune, A; Khanji, B; Kochebina, O; Komarov, I; Koopman, R F; Koppenburg, P; Korolev, M; Kozlinskiy, A; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Kucharczyk, M; Kudryavtsev, V; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanciotti, E; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J -P; Lefèvre, R; Leflat, A; Lefrançois, J; Leo, S; Leroy, O; Lesiak, T; Leverington, B; Li, Y; Li Gioi, L; 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Zhang, Y; Zhelezov, A; Zhokhov, A; Zhong, L; Zvyagin, A

    2013-07-11

    The determination of the differential branching fraction and the first angular analysis of the decay $B_s^0\\to\\phi\\mu^{+}\\mu^{-}$ are presented using data, corresponding to an integrated luminosity of $1.0\\,{\\rm fb}^{-1}$, collected by the LHCb experiment at $\\sqrt{s}=7\\,{\\rm TeV}$. The differential branching fraction is determined in bins of $q^{2}$, the invariant dimuon mass squared. Integration over the full $q^{2}$ range yields a total branching fraction of ${\\cal B}(B_s^0\\to\\phi\\mu^{+}\\mu^{-}) = (7.07\\,^{+0.64}_{-0.59}\\pm 0.17 \\pm 0.71)\\times 10^{-7}$, where the first uncertainty is statistical, the second systematic, and the third originates from the branching fraction of the normalisation channel. An angular analysis is performed to determine the angular observables $F_{\\rm L}$, $S_3$, $A_6$, and $A_9$. The observables are consistent with Standard Model expectations.

  12. Electron and ion angular distributions in resonant dissociative photoionization of H{sub 2} and D{sub 2} using linearly polarized light

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Jorge; MartIn, Fernando [Departamento de Quimica C-9, Universidad Autonoma de Madrid, 28049 Madrid (Spain)], E-mail: fernando.martin@uam.es

    2009-04-15

    We have evaluated fully differential electron angular distributions in H{sub 2} and D{sub 2} dissociative photoionization by using linearly polarized light of 20, 27 and 33 eV. At 20 eV, the distributions exhibit simple p-wave patterns, which is the signature of direct ionization through the X{sup 2}{sigma}{sub g}{sup +}(1s{sigma}{sub g}) channel. At 27 eV, where the Q{sub 1} autoionizing states are populated, we observe a similar pattern, except when the molecule is oriented perpendicularly to the polarization direction and the energy of the ejected electron is small. In contrast, at 33 eV, autoionization from the Q{sub 1} and Q{sub 2} states leads to interferences between the X{sup 2}{sigma}{sub g}{sup +}(1s{sigma}{sub g}) and {sup 2}{sigma}{sub u}{sup +}(2p{sigma}{sub u}) ionization channels that result in a strong asymmetry of the electron angular distributions along the molecular axis. This asymmetry changes rapidly with the energy of the ejected electron. Electron angular distributions integrated over all possible molecular orientations or ion angular distributions integrated over electron emission angle show no reminiscence of the above phenomena, but the corresponding asymmetry parameters dramatically change with electron and ion energies in the region of autoionizing states.

  13. Adaptive Control of Freeze-Form Extrusion Fabrication Processes (Preprint)

    National Research Council Canada - National Science Library

    Zhao, Xiyue; Landers, Robert G; Leu, Ming C

    2008-01-01

    Freeze-form Extrusion Fabrication (FEF) is an additive manufacturing process that extrudes high solids loading aqueous ceramic pastes in a layer-by-layer fashion below the paste freezing temperature for component fabrication...

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

    Science.gov (United States)

    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.

  15. Anisotropy of relativistic lepton coherent scattering at axial channeling

    International Nuclear Information System (INIS)

    Telegin, V.I.; Kanloev, A.M.; Kungurov, F.R.

    1989-01-01

    The contribution of the coherent and incoherent scattering of relativistic leptons passed through thin crystals in the channeling mode to their angular distribution is considered. The investigation was carried out by numerical integration of the motion equations for a great number of particles. It is shown that in the crystals with a thickness smaller than the dechanneling length the determining role in formation of distribution over the axit angles is played by the coherent scattering of particles by atomic chains. The effect of the multiple scattering on the angular distribution is negligibly small. 6 refs.; 4 figs

  16. Characterisation of radiation damage in perovskite using high angular resolution electron channeling x-ray spectroscopy (HARECXS)

    International Nuclear Information System (INIS)

    Smith, K.L.; Zaluzec, N.J.

    2002-01-01

    Full text: Predicting and/or modelling the occurrence of radiation damage induced defects and their effects on physical properties (eg. amorphisation induced swelling, electrical conductivity., optical response etc.) in ceramic phases requires knowledge of the displacement energies, E d , of cations and anions in those phases. In this study, High Angular Resolution Electron Channelling X-ray Spectroscopy (HARECXS) spectra were collected from perovskite (CaTiO 3 ) samples that had been exposed to high-energy electrons or high-energy heavy ions. Calculations based on experimental data were then used to indicate the E d of the cations in perovskite. The HARECXS measurements were conducted on a Philips EM 420T AEM (LaB6 source, operated at 120 kV) fitted with an EDAX ultra thin window Si(Li) detector. The specimen was first manually oriented to an appropriate zone axis. Then control of the relative orientation of the incident probe was accomplished via direct computer control of the beam tilt coils, Typical acquisition times for a complete two-dimensional scan were 18-24 hours, while one dimensional scans ranged from 1-5 hours. Our experiments established that: a) HARECXS can detect radiation damage in perovskite caused by either high energy heavy ions or high energy electrons, b) the HARECXS signature of perovskite shows a systematic change with ion dose, c) HARECXS detects damage in perovskite that has been irradiated with 900kV electrons and does not detect damage in perovskite that has been irradiated with 620kV electrons, indicating the existance of an electron irradiation damage threshold. Calculations based on the latter results indicate that the displacement energy, E d of calcium and titanium in perovskite lie between 50 and 85eV. Copyright (2002) Australian Society for Electron Microscopy Inc

  17. Design of an extrusion screw and solid fuel produced from coconut shell

    Directory of Open Access Journals (Sweden)

    Madhiyanon, T

    2006-03-01

    Full Text Available The objectives were to design an extrusion screw to produce biomass solid fuel in a cold extrusion process, and investigate the effects of molasses used as a selected adhesive on the physical properties of extruded products. The material employed consisted of crushed coconut shell char and coconut fiber char mixed at a ratio of 40:60. The ratios of molasses in the mixture were 10:100, 15:100 and 20:100 (by weight and the extrusion die angles were 1.0, 1.1, 1.2, and 1.3 degrees gradation per experiment. The experimental results showed that the newly designed screw could function properly in the output range 0.75-0.90 kg/min, which is close to the design value. Regarding the molasses's effect on solid fuel properties, increasing the share of molasses was positive for both output and strength of the resulting briquettes, whereas the results of increasing die angle showed decreases in both output and strength. The compressive strength varied between 2.49-2.87 MPa in all circumstances, which was considerably higher than acceptable industrial level. Furthermore, the extruded solid fuel showed excellent resistance to impact force. Regarding energy consumption, the amount of electrical energy used in the extrusion process was insignificant, ranging between 0.040-0.079 kWh/kg.

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

    Science.gov (United States)

    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.

  19. Channeling of protons in various types of radially compressed carbon nanotubes

    International Nuclear Information System (INIS)

    Karabarbounis, A.; Sarros, S.; Trikalinos, Ch.

    2015-01-01

    Channeling of 10 MeV protons in various types of radially compressed chiral carbon nanotubes is considered. Monte Carlo simulation program is used for the calculation of the trajectories, energy losses and angular distributions of protons in nanotubes of various lengths, where the potential in Doyle–Turner approximation is used to describe the interaction between a proton and a nanotube. Carbon nanotubes, which are considered, are radially compressed at the centre or at both ends. The results show that in some cases a decreased angular distribution of the beam is observed, compared with propagation through a straight nanotube. Furthermore, the energy distribution of channeled protons in nanotubes present a series of small peaks besides a main one, the number of which depends on the nanotube length and the angle of incidence, which in some cases are significantly high

  20. Channeling of protons in various types of radially compressed carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Karabarbounis, A. [Department of Physics, Section of Nuclear and Particle Physics, University of Athens, Panepistimioupolis, Ilissia, 15771 Athens (Greece); Sarros, S., E-mail: stsarros@phys.uoa.gr [Department of Physics, Section of Nuclear and Particle Physics, University of Athens, Panepistimioupolis, Ilissia, 15771 Athens (Greece); Trikalinos, Ch. [Department of Philosophy and History of Science, University of Athens, Panepistimioupolis, Ilissia, 15771 Athens (Greece)

    2015-07-15

    Channeling of 10 MeV protons in various types of radially compressed chiral carbon nanotubes is considered. Monte Carlo simulation program is used for the calculation of the trajectories, energy losses and angular distributions of protons in nanotubes of various lengths, where the potential in Doyle–Turner approximation is used to describe the interaction between a proton and a nanotube. Carbon nanotubes, which are considered, are radially compressed at the centre or at both ends. The results show that in some cases a decreased angular distribution of the beam is observed, compared with propagation through a straight nanotube. Furthermore, the energy distribution of channeled protons in nanotubes present a series of small peaks besides a main one, the number of which depends on the nanotube length and the angle of incidence, which in some cases are significantly high.

  1. A Comparison of Apical Bacterial Extrusion in Manual, ProTaper Rotary, and One Shape Rotary Instrumentation Techniques.

    Science.gov (United States)

    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 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 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.

  2. Angular Momentum in Dwarf Galaxies

    Directory of Open Access Journals (Sweden)

    Del Popolo A.

    2014-06-01

    Full Text Available We study the “angular momentum catastrophe” in the framework of interaction among baryons and dark matter through dynamical friction. By means of Del Popolo (2009 model we simulate 14 galaxies similar to those investigated by van den Bosch, Burkert and Swaters (2001, and calculate the distribution of their spin parameters and the angular momenta. Our model gives the angular momentum distribution which is in agreement with the van den Bosch et al. observations. Our result shows that the “angular momentum catastrophe” can be naturally solved in a model that takes into account the baryonic physics and the exchange of energy and angular momentum between the baryonic clumps and dark matter through dynamical friction.

  3. MM98.36 Strain Paths in Extrusion

    DEFF Research Database (Denmark)

    Lindegren, Maria; Wiwe, Birgitte; Wanheim, Tarras

    1998-01-01

    The extrusion process has been investigated for different geometries, in order to study the strain path of different material elements during their movements through the plastic zone. This is done by using the FEM code DEFORM and physical simulation with wax togehter with the coefficient method. ....... Calculations of strain paths have also been performed by ABAQUS....

  4. Spinning and tumbling of micron-sized triangles in a micro-channel shear flow

    Science.gov (United States)

    Fries, J.; Kumar, M. Vijay; Mihiretie, B. Mekonnen; Hanstorp, D.; Mehlig, B.

    2018-03-01

    We report on measurements of the angular dynamics of micron-sized equilaterally triangular platelets suspended in a micro-channel shear flow. Our measurements confirm that such particles spin and tumble like a spheroid in a simple shear. Since the triangle has corners, we can observe the spinning directly. In general, the spinning frequency is different from the tumbling frequency and the spinning is affected by tumbling. This gives rise to doubly periodic angular dynamics.

  5. Generation and use of process maps for hot extrusion of seamless tubes for nuclear applications

    International Nuclear Information System (INIS)

    Vaibhaw, Kumar; Jha, S.K.; Saibaba, N.; Jayaraj, R.N.

    2009-01-01

    Full text: Hot extrusion is known as significant bulk deformation step in manufacturing of seamless tube production. Elevated temperature deformation carried out above the recrystallization temperature would enable imposition of large strains in single step. This deformation causes a significant change in the microstructure of the material and depends on extrusion process parameters such as temperature and strain rate (Ram speed). Basic microstructure developed at this deformation stage has significant bearing on the final properties of the material fabricated with subsequent cold working steps. Zirconium alloys and special nuclear grade austenitic stainless steels are two important groups of materials used as structural and core components in thermal and fast reactors world wide respectively. The properties of former alloy are very sensitive to the thermo mechanical fabrication steps initiated with hot extrusion due to their anisotropic deformation behaviour. However, nuclear grade austenitic stainless steels have many variants from their commercial grades in terms of micro and macro alloy chemistry. Factors such as these significantly affect the workability of the materials and require proper selection of extrusion parameters especially working temperature and extrusion speed plays a key role in the quality of the product. Modern developments in processing technology envisage the application of processing maps based on dynamic material model for selection of hot extrusion parameters. The present paper is aimed at bringing out significance of the map in selection of working domain with respect to the industrial process conditions for both groups of nuclear materials mentioned earlier. Developed process maps of certain alloys suggest use of extremely slow strain rate and low temperature extrusion which can not be achieved during bulk processing due to design of equipment and heat transfer constraints in industrial scale production. Attempts are made to highlight

  6. Pellet manufacturing by extrusion-spheronization using process analytical technology

    DEFF Research Database (Denmark)

    Sandler, Niklas; Rantanen, Jukka; Heinämäki, Jyrki

    2005-01-01

    The aim of this study was to investigate the phase transitions occurring in nitrofurantoin and theophylline formulations during pelletization by extrusion-spheronization. An at-line process analytical technology (PAT) approach was used to increase the understanding of the solid-state behavior...... of the active pharmaceutical ingredients (APIs) during pelletization. Raman spectroscopy, near-infrared (NIR) spectroscopy, and X-ray powder diffraction (XRPD) were used in the characterization of polymorphic changes during the process. Samples were collected at the end of each processing stage (blending......, granulation, extrusion, spheronization, and drying). Batches were dried at 3 temperature levels (60 degrees C, 100 degrees C, and 135 degrees C). Water induced a hydrate formation in both model formulations during processing. NIR spectroscopy gave valuable real-time data about the state of water in the system...

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

    Science.gov (United States)

    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.

  8. Microstructures and recrystallization behavior of severely hot-deformed tungsten

    International Nuclear Information System (INIS)

    Mathaudhu, S.N.; De Rosset, A.J.; Hartwig, K.T.; Kecskes, L.J.

    2009-01-01

    When coarse-grained (CG) tungsten (W) is heavily worked by equal-channel angular extrusion (ECAE), the grain size is reduced to the ultrafine-grained/nanocrystalline regimes (UFG/NC) and the strength and ductility increase. Because of the brittle nature of CG W, the material must be hot-extruded, and, if the temperatures are near the recrystallization temperature (T rc ), gains in properties may not be maximized. In this study, the recrystallization behavior of ECAE-processed CG W is examined as a function of the imparted strain (i.e., number of extrusions) and the hot-working extrusion temperature. Up to four ECAE passes were performed in tooling with a 90 deg. channel intersection, and at temperatures of 1000 deg. C or 1200 deg. C. Subsequent 60 min annealing of the worked material to 1600 deg. C allowed for the determination of T rc . Vickers microhardness measurements and scanning electron microscopy, were used to characterize the microstructures in the as-worked and recrystallized states. The ECAE-processed W shows increased microstructural break-up and refinement with increasing strain and decreasing hot-working temperature in the fully worked state. T rc was determined to be ∼1400 deg. C, which is nearly independent of the number of extrusions and the working temperature. These results show that if ECAE is accomplished below 1400 deg. C (i.e., at 1000 deg. C or lower) the attractive properties of the UFG/NC-worked W may be retained. Specifically, below 1000 deg. C, with increasing strain imparted to the material, high hardness values with a concomitant grain size refinement (∼350 nm) could be expected

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

    Science.gov (United States)

    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.

  10. A Novel Continuous Extrusion Process to Fabricate Wedge-Shaped Light Guide Plates

    Directory of Open Access Journals (Sweden)

    Wen-Tse Hsiao

    2013-01-01

    Full Text Available Backlight modules are key components in thin-film transistor liquid crystal displays (TFT-LCD. Among the components of a backlight module, the light guide plate (LGP plays the most important role controlling the light projected to the eyes of users. A wedge-shaped LGP, with its asymmetrical structure, is usually fabricated by an injection proces, but the fabrication time of this process is long. This study proposes a continuous extrusion process to fabricate wedge-shaped LGPs. This continuous process has advantages for mass production. Besides a T-die and rollers, this system also has an in situ monitor of the melt-bank that forms during the extrusion process, helping control the plate thickness. Results show that the melt bank has a close relationship with the plate thickness. The temperature of the bottom heater and roller was adjusted to reduce the surface deformation of the wedge-shaped plate. This continuous extrusion system can successfully manufacture wedge-shaped LGPs for mass production.

  11. 75 FR 22109 - Aluminum Extrusions from the People's Republic of China: Initiation of Antidumping Duty...

    Science.gov (United States)

    2010-04-27

    ... Aluminium, Ltd., a producer of aluminum extrusions, for the 2008 2009 fiscal year. See Volume II of the..., produced by an extrusion process, made from aluminum alloys having metallic elements corresponding to the alloy series designations published by The Aluminum Association commencing with the numbers 1, 3, and 6...

  12. The Development and Numerical Analysis of the Conical Radiator Extrusion Process

    Directory of Open Access Journals (Sweden)

    Michalczyk J.

    2017-12-01

    Full Text Available The article presents a newly developed method for single-operation extrusion of conical radiators. This is the author’s radiator manufacturing method being the subject of a patent application. The proposed method enables the manufacture of radiators either with or without an inner opening and with an integral plate. Selected results of numerical computations made within Forge®3D, a finite element method (FEM-based software program, were presented during the analysis of the process. A comparative analysis of the proposed manufacturing method using the double-sided extrusion method was also made.

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

    DEFF Research Database (Denmark)

    Pedersen, Thomas Ø

    2000-01-01

    of describing the elastic-plastic material behaviour under cyclic loadings is used to study the effects of different pre-stressing concepts on the accumulation of plastic strain and the development of fatigue damage. The results show, that the accumulation of plastic strain in the critical region can......Forward extrusion dies typically fail due to transverse fatigue cracks or wear. Fatigue cracks are initiated in regions where the material is subjected to repeated plastic deformations, e.g. the transition radius in a forward extrusion die, in the present work, a material model capable...... be controlled by means of the pre-stressing system or the geometry of the die insert. (C) 2000 Elsevier Science B.V. All rights reserved....

  14. Chemical, physical and nutritional changes in soybean meal as a result of toasting and extrusion cooking

    NARCIS (Netherlands)

    Marsman, G.J.P.

    1998-01-01

    The effect of soybean meal extrusion and the development of shear forces during single-screw extrusion was compared with the toasting process of soybean meal. Attention was focused on chemical, physical and nutritional changes during these thermo-mechanical

  15. Angular distribution of W boson pairs at a heavy Z-resonance

    International Nuclear Information System (INIS)

    Nandi, S.; Rizzo, T.G.

    1987-05-01

    In theories with an extra U(1) gauge boson (Z 2 ) at low energies. W boson pairs may be produced copiously by the process e + e - → Z 2 → W + W - at the Z 2 -resonance. We show that the angular distribution of the W pairs (produced at the Z 2 -resonance) is very different from that in the standard model, at the same center of mass energy, where it is dominated by t-channel neutrino exchange. These distributions will also be useful in distinguishing among the various models containing an extra Z-boson

  16. Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling

    Energy Technology Data Exchange (ETDEWEB)

    Randall S. Seright

    2007-09-30

    This final technical progress report describes work performed from October 1, 2004, through May 16, 2007, for the project, 'Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling'. We explored the potential of pore-filling gels for reducing excess water production from both fractured and unfractured production wells. Several gel formulations were identified that met the requirements--i.e., providing water residual resistance factors greater than 2,000 and ultimate oil residual resistance factors (F{sub rro}) of 2 or less. Significant oil throughput was required to achieve low F{sub rro} values, suggesting that gelant penetration into porous rock must be small (a few feet or less) for existing pore-filling gels to provide effective disproportionate permeability reduction. Compared with adsorbed polymers and weak gels, strong pore-filling gels can provide greater reliability and behavior that is insensitive to the initial rock permeability. Guidance is provided on where relative-permeability-modification/disproportionate-permeability-reduction treatments can be successfully applied for use in either oil or gas production wells. When properly designed and executed, these treatments can be successfully applied to a limited range of oilfield excessive-water-production problems. We examined whether gel rheology can explain behavior during extrusion through fractures. The rheology behavior of the gels tested showed a strong parallel to the results obtained from previous gel extrusion experiments. However, for a given aperture (fracture width or plate-plate separation), the pressure gradients measured during the gel extrusion experiments were much higher than anticipated from rheology measurements. Extensive experiments established that wall slip and first normal stress difference were not responsible for the pressure gradient discrepancy. To explain the discrepancy, we noted that the aperture for gel flow (for mobile gel wormholing through concentrated

  17. Effects of terraces, surface steps and 'over-specular' reflection due to inelastic energy losses on angular scattering spectra for glancing incidence scattering

    CERN Document Server

    Danailov, D; O'Connor, D J

    2002-01-01

    Recent experiments and our molecular-dynamics simulations indicate that the main signal of the angular scattering spectra of glancing incidence scattering are not affected by the thermal motion of surface atoms and can be explained by our row-model with averaged cylindrical potentials. At the ICACS-18 Conference [Nucl. Instr. and Meth. B 164-165 (2000) 583] we reported good agreement between experimental and calculated multimodal azimuthal angular scattering spectra for the glancing scattering of 10 and 15 keV [Nucl. Instr. and Meth. B 180 (2001) 265, Appl. Surf. Sci. 171 (2001) 113] He sup 0 beam along the [1 0 0] direction on the Fe(1 0 0) face. Our simulations also predicted that in contrast to the 2D angular scattering distribution, the 1D azimuthal angular distribution of scattered particles is very sensitive to the interaction potential used. Here, we report more detailed calculations incorporating the influence of terraces and surface steps on surface channeling, which show a reduction of the angular s...

  18. Data-oriented development with AngularJS

    CERN Document Server

    Waikar, Manoj

    2015-01-01

    This book helps beginner-level AngularJS developers organize AngularJS applications by discussing important AngularJS concepts and best practices. If you are an experienced AngularJS developer but haven't written directives or haven't created custom HTML controls before, then this book is ideal for you.

  19. Residual stress and its effect on the mechanical properties of Y-doped Mg alloy fabricated via back-pressure assisted equal channel angular pressing (ECAP-BP)

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Jianghua, E-mail: j_shen@live.cn [Department of Mechanical Engineering, University of North Carolina at Charlotte, Charlotte, NC 28223-0001 (United States); School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072 (China); Gärtnerová, Viera [Laboratory of Nanostructures and Nanomaterials, Institute of Physics of the ASCR, Na Slovance 2, CZ – 182 21, Prague 8 (Czech Republic); Kecskes, Laszlo J. [US Army Research Laboratory, Aberdeen Proving Ground, MD 21005-5069 (United States); Kondoh, Katsuyoshi [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaragi, Osaka 567-0047 (Japan); Jäger, Aleš, E-mail: jager@fzu.cz [Laboratory of Nanostructures and Nanomaterials, Institute of Physics of the ASCR, Na Slovance 2, CZ – 182 21, Prague 8 (Czech Republic); Wei, Qiuming [Department of Mechanical Engineering, University of North Carolina at Charlotte, Charlotte, NC 28223-0001 (United States)

    2016-07-04

    In this study, pure magnesium (Mg) and Mg-0.6 wt% yttrium (Y) binary alloy were fabricated via casting followed by room temperature equal channel angular pressing (ECAP) using an applied back pressure (BP). Microstructural examination after ECAP-BP revealed a fine-grained Mg-Y alloy with a high residual stress level, whereas, the pure Mg exhibited a well-recrystallized microstructure with uniform and equiaxed grains, but retaining very little residual stress. The Y atoms were present in the Mg matrix as solid solutes and acted as dislocation and grain boundary blockers, thus suppressing dynamic recovery and/or recrystallization during the ECAP process. The Mg-Y alloy had an average grain size of ~400 nm, approximately one order smaller than that of pure Mg. The combination of high residual stress and ultrafine grains of the Mg-Y alloy gave rise to a significant difference in its mechanical behavior from that of the pure Mg, under both quasi-static and dynamic compressive loading.

  20. AngularJS web application development

    CERN Document Server

    Darwin, Peter Bacon

    2013-01-01

    The book will be a step-by-step guide showing the readers how to build a complete web app with AngularJSJavaScript developers who want to learn AngularJS for developing web apps. Knowledge of JavaScript and HTML is expected. No knowledge of AngularJS is required.

  1. Complex deformation routes for direct recycling aluminium alloy scrap via industrial hot extrusion

    Science.gov (United States)

    Paraskevas, Dimos; Kellens, Karel; Kampen, Carlos; Mohammadi, Amirahmad; Duflou, Joost R.

    2018-05-01

    This paper presents the final results of an industrial project, aiming for direct hot extrusion of wrought aluminium alloy scrap at an industrial scale. Two types of complex deformation/extrusion routes were tested for the production of the same profile, starting from AA6060 scrap in form of machining chips. More specifically scrap-based billets were extruded through: a 2-porthole and a 4-porthole die-set, modified for enhanced scrap consolidation and grain refinement. For comparison reasons, cast billets of the same alloy were extruded through the modified 2-porthole die set. The tensile testing results as well as microstructural investigations show that the 4-porthole extrusion route further improves scrap consolidation compared to the 2-porthole die output. The successful implementation of solid state recycling, directly at industrial level, indicates the technological readiness level of this research.

  2. Angular momentum of dwarf galaxies

    Science.gov (United States)

    Kurapati, Sushma; Chengalur, Jayaram N.; Pustilnik, Simon; Kamphuis, Peter

    2018-05-01

    Mass and specific angular momentum are two fundamental physical parameters of galaxies. We present measurements of the baryonic mass and specific angular momentum of 11 void dwarf galaxies derived from neutral hydrogen (HI) synthesis data. Rotation curves were measured using 3D and 2D tilted ring fitting routines, and the derived curves generally overlap within the error bars, except in the central regions where, as expected, the 3D routines give steeper curves. The specific angular momentum of void dwarfs is found to be high compared to an extrapolation of the trends seen for higher mass bulge-less spirals, but comparable to that of other dwarf irregular galaxies that lie outside of voids. As such, our data show no evidence for a dependence of the specific angular momentum on the large scale environment. Combining our data with the data from the literature, we find a baryonic threshold of ˜109.1 M⊙ for this increase in specific angular momentum. Interestingly, this threshold is very similar to the mass threshold below which the galaxy discs start to become systematically thicker. This provides qualitative support to the suggestion that the thickening of the discs, as well as the increase in specific angular momentum, are both results of a common physical mechanism, such as feedback from star formation. Quantitatively, however, the amount of star formation observed in our dwarfs appears insufficient to produce the observed increase in specific angular momentum. It is hence likely that other processes, such as cold accretion of high angular momentum gas, also play a role in increasing the specific angular momentum.

  3. Bibliography of ceramic extrusion and plasticity

    Energy Technology Data Exchange (ETDEWEB)

    Janney, M.A.; Vance, M.C.; Jordan, A.C.; Kertesz, M.P.

    1987-03-01

    A comprehensive bibliography of ceramic extrusion and plasticity has been compiled. Over 670 abstracts are included covering the period 1932 to 1984. Citations cover a wide range of interests from basic science investigations to engineering ''tips'' and include references to brick and tile, whitewares, technical ceramics, theoretical models, engineering analyses, forming, drying, and raw materials. In addition to the citations, there are numerous indices to make the bibliography easy to use.

  4. Preventing Silicone Tube Extrusion after Nasolacrimal Duct Intubation in Children

    Directory of Open Access Journals (Sweden)

    Ali-Akbar Sabermoghaddam

    2010-01-01

    Full Text Available Herein we report our experience with a simple technique for reducing the rate of silicone tube extrusion after nasolacrimal duct (NLD intubation for congenital NLD obstruction. Medical records of children older than 2 years, with or without history of failed probing, who had undergone NLD intubation with a Crawford silicone tube over a period of 4 years were reviewed. In all subjects, one end of the Crawford tube was passed through a piece of scalp vein tubing followed by applying one or two knots. All Crawford tubes were removed after 3 months. Main outcome measures included complications such as tube extrusion, nasal discharge, crust formation and pyogenic granuloma formation. Fifty-seven patients, including 49 unilateral and 8 bilateral cases with mean age of 3.8΁1.6 (range, 2 to 11.5 years were operated. No complications such as tube dislodgement, significant nasal discharge, crust or pyogenic granuloma formation occurred prior to Crawford tube removal. All silicone tubes were successfully removed from the nasal cavity. In conclusion, passing one end of the Crawford tube through a small piece of scalp vein tubing before knotting it in the nasal cavity seems to decrease the rate of tube extrusion which is the most common complication following NLD intubation in children.

  5. Multidrug and toxin extrusion proteins as transporters of antimicrobial drugs.

    Science.gov (United States)

    Nies, Anne T; Damme, Katja; Schaeffeler, Elke; Schwab, Matthias

    2012-12-01

    Antimicrobial drugs are essential in the treatment of infectious diseases. A better understanding of transport processes involved in drug disposition will improve the predictability of drug-drug interactions with consequences for drug response. Multidrug And Toxin Extrusion (MATE; SLC47A) proteins are efflux transporters mediating the excretion of several antimicrobial drugs as well as other organic compounds into bile and urine, thereby contributing to drug disposition. This review summarizes current knowledge of the structural and molecular features of human MATE transporters including their functional role in drug transport with a specific focus on antimicrobial drugs. The PubMed database was searched using the terms "MATE1," "MATE-2K," "MATE2," "SLC47A1," "SLC47A2," and "toxin extrusion protein" (up to June 2012). MATE proteins have been recognized as important transporters mediating the final excretion step of cationic drugs into bile and urine. These include the antiviral drugs acyclovir, amprenavir, and ganciclovir, the antibiotics cephalexin, cephradine and levofloxacin, as well as the antimalarial agents chloroquine and quinine. It is therefore important to enhance our understanding of the role of MATEs in drug extrusion with particular emphasis on the functional consequences of genetic variants on disposition of these antimicrobial drugs.

  6. Structure-Property Correlations in Al-Li Alloy Integrally Stiffened Extrusions

    Science.gov (United States)

    Hales, Stephen J.; Hafley, Robert A.

    2001-01-01

    The objective of this investigation was to establish the relationship between mechanical property anisotropy, microstructure and crystallographic texture in integrally 'T'-stiffened extruded panels fabricated from the Al-Li alloys 2195, 2098 and 2096. In-plane properties were measured as a function of orientation at two locations in the panels, namely mid-way between (Skin), and directly beneath (Base), the integral 'T' stiffeners. The 2195 extrusion exhibited the best combination of strength and toughness, but was the most anisotropic. The 2098 extrusion exhibited lower strength and comparable toughness, but was more isotropic than 2195. The 2096 extrusion exhibited the lowest strength and poor toughness, but was the most isotropic. All three alloys exhibited highly elongated grain structures and similar location-dependent variations in grain morphology. The textural characteristics comprised a beta + fiber texture, similar to rolled product, in the Skin regions and alpha + fiber texture, comparable to axisymmetric extruded product, in the Base regions. In an attempt to quantitatively correlate texture with yield strength anisotropy, the original 'full constraint' Taylor model and a variant of the 'relaxed constraint' model, explored by Wert et al., were applied to the data. A comparison of the results revealed that the Wert model was consistently more accurate than the Taylor model.

  7. Textures and mechanical properties in rare-earth free quasicrystal reinforced Mg-Zn-Zr alloys prepared by extrusion

    International Nuclear Information System (INIS)

    Ohhashi, S.; Kato, A.; Demura, M.; Tsai, A.P.

    2011-01-01

    Highlights: → Powder-metallurgical warm extrusion made quasicrystal dispersing Mg alloys. → Mg extrusions containing quasicrystals showed randomized textures. → These extrusion showed the enhancement of mechanical properties at 150 deg. C. - Abstract: Microstructure and mechanical properties of quasicrystals dispersed Mg alloys prepared by warm extrusion of the mixtures of Mg and Zn-Mg-Zr quasicrystalline (Qc) powders have been studied. Strong texture oriented along a [101-bar 0] direction observed in pure Mg was reduced in Qc-dispersed samples, as verified by pole figure method and electron back scattering diffraction. The ultimate tensile strengths at 150 deg. C for Qc-dispersed extrusions were much higher than 110 MPa for pure Mg, which drastically reached 156 MPa for 15 wt.% Qc by preventing the motion of dislocations. Elongation was improved by the randomization of grain orientation: from 5.7% for pure Mg to 12.9% for 10 wt.% Qc at room temperature; from 15% for pure Mg to 37.1% for 5 wt.% Qc at 150 deg. C.

  8. Positron energy distributions from a hybrid positron source based on channeling radiation

    International Nuclear Information System (INIS)

    Azadegan, B.; Mahdipour, A.; Dabagov, S.B.; Wagner, W.

    2013-01-01

    A hybrid positron source which is based on the generation of channeling radiation by relativistic electrons channeled along different crystallographic planes and axes of a tungsten single crystal and subsequent conversion of radiation into e + e − -pairs in an amorphous tungsten target is described. The photon spectra of channeling radiation are calculated using the Doyle–Turner approximation for the continuum potentials and classical equations of motion for channeled particles to obtain their trajectories, velocities and accelerations. The spectral-angular distributions of channeling radiation are found applying classical electrodynamics. Finally, the conversion of radiation into e + e − -pairs and the energy distributions of positrons are simulated using the GEANT4 package

  9. A novel angular acceleration sensor based on the electromagnetic induction principle and investigation of its calibration tests.

    Science.gov (United States)

    Zhao, Hao; Feng, Hao

    2013-08-12

    An angular acceleration sensor can be used for the dynamic analysis of human and joint motions. In this paper, an angular acceleration sensor with novel structure based on the principle of electromagnetic induction is designed. The method involves the construction of a constant magnetic field by the excitation windings of sensor, and the cup-shaped rotor that cut the magnetic field. The output windings of the sensor generate an electromotive force, which is directly proportional to the angular acceleration through the electromagnetic coupling when the rotor has rotational angular acceleration. The mechanical structure and the magnetic working circuit of the sensor are described. The output properties and the mathematical model including the transfer function and state-space model of the sensor are established. The asymptotical stability of the sensor when it is working is verified by the Lyapunov Theorem. An angular acceleration calibration device based on the torsional pendulum principle is designed. The method involves the coaxial connection of the angular acceleration sensor, torsion pendulum and a high-precision angle sensor, and then an initial external force is applied to the torsion pendulum to produce a periodic damping angle oscillation. The angular acceleration sensor and the angle sensor will generate two corresponding electrical signals. The sensitivity coefficient of the angular acceleration sensor can be obtained after processing these two-channel signals. The experiment results show that the sensitivity coefficient of the sensor is about 17.29 mv/Krad·s2. Finally, the errors existing in the practical applications of the sensor are discussed and the corresponding improvement measures are proposed to provide effective technical support for the practical promotion of the novel sensor.

  10. Identification of an HV 1 voltage-gated proton channel in insects.

    Science.gov (United States)

    Chaves, Gustavo; Derst, Christian; Franzen, Arne; Mashimo, Yuta; Machida, Ryuichiro; Musset, Boris

    2016-04-01

    The voltage-gated proton channel 1 (HV 1) is an important component of the cellular proton extrusion machinery and is essential for charge compensation during the respiratory burst of phagocytes. HV 1 has been identified in a wide range of eukaryotes throughout the animal kingdom, with the exception of insects. Therefore, it has been proposed that insects do not possess an HV 1 channel. In the present study, we report the existence of an HV 1-type proton channel in insects. We searched insect transcriptome shotgun assembly (TSA) sequence databases and found putative HV 1 orthologues in various polyneopteran insects. To confirm that these putative HV 1 orthologues were functional channels, we studied the HV 1 channel of Nicoletia phytophila (NpHV 1), an insect of the Zygentoma order, in more detail. NpHV 1 comprises 239 amino acids and is 33% identical to the human voltage-gated proton channel 1. Patch clamp measurements in a heterologous expression system showed proton selectivity, as well as pH- and voltage-dependent gating. Interestingly, NpHV 1 shows slightly enhanced pH-dependent gating compared to the human channel. Mutations in the first transmembrane segment at position 66 (Asp66), the presumed selectivity filter, lead to a loss of proton-selective conduction, confirming the importance of this aspartate residue in voltage-gated proton channels. Nucleotide sequence data have been deposited in the GenBank database under accession number KT780722. © 2016 Federation of European Biochemical Societies.

  11. The total angular moment selectivity in 7Li(α, α) 7Li(4.63 MeV, 7/2-) reaction at Eα = 27.2 MeV

    International Nuclear Information System (INIS)

    Dmitrenko, V.N.; Kozyr', Yu.E.

    1995-01-01

    The DWBA calculation of tensor polarisation of residual nuclei for direct inelastic scattering 7 Li(α, α) 7 Li(4.63 MeV, 7/2 - ) gives the lest approximation to experimental data at selected total angular moment and parity values J π 13/2 + . The microscopic coupled channel calculation also predicts a significant role of total angular moment states with J ≥ 13/2. at E α 27.2 MeV

  12. Physical properties, molecular structures and protein quality of texturized whey protein isolate: effect of extrusion temperature

    Science.gov (United States)

    Extrusion is a powerful food processing operation, which utilizes high temperature and high shear force to produce a product with unique physical and chemical characteristics. Texturization of whey protein isolate (WPI) through extrusion for the production of protein fortified snack foods has provid...

  13. 78 FR 67115 - Aluminum Extrusions From the People's Republic of China: Intent To Rescind 2012 Countervailing...

    Science.gov (United States)

    2013-11-08

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-968] Aluminum Extrusions From the People's Republic of China: Intent To Rescind 2012 Countervailing Duty Administrative Review, in Part... administrative review of the countervailing duty (CVD) order on aluminum extrusions from the People's Republic of...

  14. Joint image reconstruction method with correlative multi-channel prior for x-ray spectral computed tomography

    DEFF Research Database (Denmark)

    Kazantsev, Daniil; Jørgensen, Jakob Sauer; Andersen, Martin S

    2018-01-01

    peaks. The acquired energy-binned data, however, suffer from low signal-to-noise ratio, acquisition artifacts, and frequently angular undersampled conditions. New regularized iterative reconstruction methods have the potential to produce higher quality images and since energy channels are mutually...... to encourage joint smoothing directions. In particular, the method selects reference channels from which to propagate structure in an adaptive and stochastic way while preferring channels with a high data signal-to-noise ratio. The method is compared with current state-of-the-art multi-channel reconstruction...

  15. Secondary electron emission induced by channeled relativistic electrons in a (1 1 0) Si crystal

    International Nuclear Information System (INIS)

    Korotchenko, K.B.; Kunashenko, Yu P.; Tukhfatullin, T.A.

    2012-01-01

    A new effect that accompanies electrons channeled in a crystal is considered. This phenomenon was previously predicted was called channeling secondary electron emission (CSEE). The exact CSEE cross-section on the basis of using the exact Bloch wave function of electron channeled in a crystal is obtained. The detailed investigation of CSEE cross-section is performed. It is shown that angular distribution of electrons emitted due to CSEE has a complex form.

  16. Classical theory of the Kumakhov radiation in axial channeling

    International Nuclear Information System (INIS)

    Khokonov, M.K.; Komarov, F.F.; Telegin, V.I.

    1984-01-01

    The paper considers radiation of ultrarelativistic electrons in axial channeling initially predicted by Kumakhov. The consideration is based on the results of solution of the Fokker-Planck equation. The spectral-angular characteristics of the Kumakhov radiation in thick single crystals are calculated. It is shown that in heavy single crystals the energy losses on radiation can amount to a considerable portion of the initial beam energy. The possibility of a sharp increase of radiation due to a decrease of crystal temperature is discussed. It is shown that radiation intensity in axial channeling is weakly dependent on the initial angle of the electron entrance into the channel if this angle changes within the limits of a critical one. (author)

  17. Extrusion of Debris from Primary Molar Root Canals following Instrumentation with Traditional and New File Systems.

    Science.gov (United States)

    Thakur, Bhagyashree; Pawar, Ajinkya M; Kfir, Anda; Neelakantan, Prasanna

    2017-11-01

    To assess the amount of debris extruded apically during instrumentation of distal canals of extracted primary molars by three instrument systems [ProTaper Universal (PTU), ProTaper NEXT (PTN), and self-adjusting file (SAF)] compared with conventional stainless steel hand K-files (HF, control). Primary mandibular molars (n = 120) with a single distal canal were selected and randomly divided into four groups (n = 30) for root canal instrumentation using group I, HF (to size 0.30/0.02 taper), group II, PTU (to size F3), group III, PTN (to size X3), and group IV, SAF. Debris extruded during instrumentation was collected in preweighed Eppendorf tubes, stored in an incubator at 70°C for 5 days and then weighed. Statistical analysis was performed by one-way analysis of variance (ANOVA), followed by Turkey's post hoc test (p = 0.05). All the groups resulted in extrusion of debris. There was statistically significant difference (p < 0.001) in the debris extrusion between the three groups: HF (0.00133 ± 0.00012), PTU (0.00109 ± 0.00005), PTN (0.00052 ± 0.00008), and SAF (0.00026 ± 0.00004). Instrumentation with SAF resulted in the least debris extrusion when used for shaping root canals of primary molar teeth. Debris extrusion in primary teeth poses an adverse effect on the stem cells and may also alter the permanent dental germ. Debris extrusion is rarely reported for primary teeth and it is important for the clinician to know which endodontic instrumentation leads to less extrusion of debris.

  18. Reaction channels of 6,7Li+28Si at near-barrier energies

    International Nuclear Information System (INIS)

    Pakou, A; Rusek, K; Nicolis, N G; Alamanos, N; Doukelis, G; Gillibert, A; Kalyva, G; Kokkoris, M; Lagoyannis, A; Musumarra, A; Papachristodoulou, C; Perdikakis, G; Pierroutsakou, D; Pollacco, E C; Spyrou, A; Zarkadas, Ch

    2005-01-01

    The production of α-particles in the reactions 6,7 Li+ 28 Si was studied as a means to disentangle the various reaction channels at near-barrier energies. The competition between compound and direct reactions was determined by using the shape of angular distributions and statistical model calculations. DWBA calculations were also performed to probe the various direct channels. It was found that, approaching barrier, transfer channels are the most dominant for both reactions. For 7 Li+ 28 Si d-transfer is one of the contributing channels without excluding t-transfer, while for 6 Li+ 28 Si, n-transfer and p-transfer have substantial contribution but without excluding d-transfer

  19. Functionalization of whey proteins by reactive supercritical fluid extrusion

    Directory of Open Access Journals (Sweden)

    Khanitta Ruttarattanamongkol

    2012-09-01

    Full Text Available Whey protein, a by-product from cheese-making, is often used in a variety of food formulations due to its unsurpassednutritional quality and inherent functional properties. However, the possibilities for the improvement and upgrading of wheyprotein utilization still need to be explored. Reactive supercritical fluid extrusion (SCFX is a novel technique that has beenrecently reported to successfully functionalize commercially available whey proteins into a product with enhanced functionalproperties. The specific goal of this review is to provide fundamental understanding of the reinforcement mechanism andprocessing of protein functionalization by reactive SCFX process. The superimposed extrusion variables and their interactionmechanism affect the physico-chemical properties of whey proteins. By understanding the structure, functional properties andprocessing relationships of such materials, the rational design criteria for novel functionalized proteins could be developedand effectively utilized in food systems.

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

    DEFF Research Database (Denmark)

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

    2012-01-01

    Polypropylene (PP)-based polymer nanocomposites containing organically modified montmorillonite (OMMT) with and without maleic anhydride grafted PP, were compounded by twin-screw extrusion. The extrusion process was repeated various numbers of times to increase the extruder residence time (TR) and......) increased monotonically with increased TR by 70% from least dispersed to best dispersed, which was still 20% below the level for neat PP. Both the fracture initiation energy and propagation energy increased with TR, but the primary effect on ri came from the fracture propagation energy, which delivered 80...

  1. Physical simulation method for the investigation of weld seam formation during the extrusion of aluminum alloys

    NARCIS (Netherlands)

    Fang, G; Zhou, J.

    2017-01-01

    Extrusion through the porthole die is a predominant forming process used in the production of hollow aluminum alloy profiles across the aluminum extrusion industry. Longitudinal weld seams formed during the process may negatively influence the quality of extruded profiles. It is therefore of

  2. Microstructure and properties of the novel Cu–0.30Mg–0.05Ce alloy processed by equal channel angular pressing

    International Nuclear Information System (INIS)

    Duan, Y.L.; Xu, G.F.; Tang, L.; Li, Z.; Yang, G.

    2015-01-01

    A novel Cu–0.30Mg–0.05Ce (wt%) alloy was designed and prepared by melting and casting. The hot-rolled Cu–Mg–Ce alloy with an average grain size of 24.3 μm was processed by equal channel angular pressing (ECAP) via route B_C with different passes at room temperature. Moreover, microstructure evolution, mechanical properties and electrical conductivity of the alloy subjected to ECAP with different passes have been analyzed. The transmission electron microscope observation and electron backscatter diffraction analysis results show that the grains were refined significantly and the low angle boundaries generated at the initial stage of deformation were gradually transformed to the high angle boundaries with increasing the number of ECAP passes. After 8 ECAP passes, the average grain size decreased to 1.2 μm, and the fraction of high angle boundaries was 87.7%. Besides, the typical FCC shear textures ({111} , {111} and {001} ) were generated during ECAP deformation. Furthermore, tension testing results indicated that the tensile strength was remarkably improved from ∼274 MPa before ECAP to ∼588 MPa after 8 ECAP passes, maintaining an appropriate elongation of ∼11% and good electrical conductivity of 73.5% International Annealed Copper Standard (IACS), which showed bright prospect in high-speed railway as a contact wire material.

  3. Microstructure and properties of the novel Cu–0.30Mg–0.05Ce alloy processed by equal channel angular pressing

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Y.L. [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Xu, G.F., E-mail: csuxgf660302@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Nonferrous Materials Science and Engineering of Ministry of Education, Central South University, Changsha 410083 (China); Tang, L. [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Li, Z. [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Nonferrous Materials Science and Engineering of Ministry of Education, Central South University, Changsha 410083 (China); Yang, G. [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

    2015-11-11

    A novel Cu–0.30Mg–0.05Ce (wt%) alloy was designed and prepared by melting and casting. The hot-rolled Cu–Mg–Ce alloy with an average grain size of 24.3 μm was processed by equal channel angular pressing (ECAP) via route B{sub C} with different passes at room temperature. Moreover, microstructure evolution, mechanical properties and electrical conductivity of the alloy subjected to ECAP with different passes have been analyzed. The transmission electron microscope observation and electron backscatter diffraction analysis results show that the grains were refined significantly and the low angle boundaries generated at the initial stage of deformation were gradually transformed to the high angle boundaries with increasing the number of ECAP passes. After 8 ECAP passes, the average grain size decreased to 1.2 μm, and the fraction of high angle boundaries was 87.7%. Besides, the typical FCC shear textures ({111}<112>, {111}<110> and {001}<110>) were generated during ECAP deformation. Furthermore, tension testing results indicated that the tensile strength was remarkably improved from ∼274 MPa before ECAP to ∼588 MPa after 8 ECAP passes, maintaining an appropriate elongation of ∼11% and good electrical conductivity of 73.5% International Annealed Copper Standard (IACS), which showed bright prospect in high-speed railway as a contact wire material.

  4. Modelling the Thermo-Mechanical Behavior of Magnesium Alloys during Indirect Extrusion

    International Nuclear Information System (INIS)

    Steglich, D.; Ertuerk, S.; Bohlen, J.; Letzig, D.; Brocks, W.

    2010-01-01

    One of the basic metal forming process for semi-finished products is extrusion. Since extrusion involves complex thermo-mechanical and multiaxial loading conditions resulting in large strains, high strain rates and an increase in temperature due to deformation, a proper yield criterion and hardening law should be used in the numerical modelling of the process. A phenomenological model based on a plastic potential has been proposed that takes strain, strain rate and temperature dependency on flow behaviour into consideration. A hybrid methodology of experiment and finite element simulation has been adopted in order to obtain necessary model parameters. The anisotropy/asymmetry in yielding was quantified by tensile and compression tests of specimens prepared from different directions. The identification of the corresponding model parameters was performed by a genetic algorithm. A fully coupled thermo-mechanical analysis has been used in extrusion simulations for calculation of the temperature field by considering heat fluxes and heat generated due to plastic deformation. The results of the approach adopted in this study appeared to be successful showing promising predictions of the experiments and thus may be extended to be applicable to other magnesium alloys or even other hcp metals.

  5. Experimental characterization of a 400 Gbit/s orbital angular momentum multiplexed free-space optical link over 120 m.

    Science.gov (United States)

    Ren, Yongxiong; Wang, Zhe; Liao, Peicheng; Li, Long; Xie, Guodong; Huang, Hao; Zhao, Zhe; Yan, Yan; Ahmed, Nisar; Willner, Asher; Lavery, Martin P J; Ashrafi, Nima; Ashrafi, Solyman; Bock, Robert; Tur, Moshe; Djordjevic, Ivan B; Neifeld, Mark A; Willner, Alan E

    2016-02-01

    We experimentally demonstrate and characterize the performance of a 400-Gbit/s orbital angular momentum (OAM) multiplexed free-space optical link over 120 m on the roof of a building. Four OAM beams, each carrying a 100-Gbit/s quadrature-phase-shift-keyed channel are multiplexed and transmitted. We investigate the influence of channel impairments on the received power, intermodal crosstalk among channels, and system power penalties. Without laser tracking and compensation systems, the measured received power and crosstalk among OAM channels fluctuate by 4.5 dB and 5 dB, respectively, over 180 s. For a beam displacement of 2 mm that corresponds to a pointing error less than 16.7 μrad, the link bit error rates are below the forward error correction threshold of 3.8×10(-3) for all channels. Both experimental and simulation results show that power penalties increase rapidly when the displacement increases.

  6. A proposed measurement of optical orbital and spin angular momentum and its implications for photon angular momentum

    Directory of Open Access Journals (Sweden)

    Elliot Leader

    2018-04-01

    Full Text Available The expression for the total angular momentum carried by a laser optical vortex beam, splits, in the paraxial approximation, into two terms which seem to represent orbital and spin angular momentum respectively. There are, however, two very different competing versions of the formula for the spin angular momentum, one based on the use of the Poynting vector, as in classical electrodynamics, the other related to the canonical expression for the angular momentum which occurs in Quantum Electrodynamics. I analyze the possibility that a sufficiently sensitive optical measurement could decide which of these corresponds to the actual physical angular momentum carried by the beam. Keywords: Photon, Angular momentum, Laser optics, Particle physics

  7. AngularJS : yksisivuisen web-sovelluksen käyttöliittymän toteutus AngularJS:llä

    OpenAIRE

    Suomijoki, Juha

    2015-01-01

    Opinnäytetyössä tutkittiin mikä on AngularJS-JavaScript-ohjelmistokehys ja miten se soveltuu yksisivuisen web-sovelluksen käyttöliittymän toteutukseen. AngularJS on vuonna 2012 julkaistu Googlen ylläpitämä JavaScript-ohjelmistokehys, joka on tarkoitettu ensisijaisesti yksisivuisten web-sovellusten kehittämiseen. Opinnäytetyön teoriaosuudessa tutkittiin mikä AngularJS on ja mitkä ovat AngularJS:n keskeiset konseptit ja sovelluskomponentit. Tarkastelu pohjautui AngularJS:stä kirjoitettu...

  8. Quark Orbital Angular Momentum

    Directory of Open Access Journals (Sweden)

    Burkardt Matthias

    2015-01-01

    Full Text Available Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. We find that the difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asymmetries in semi-inclusive deep-inelastic scattering.

  9. Effect of materials and temperature on the forward extrusion of magnesium alloys

    International Nuclear Information System (INIS)

    Chandrasekaran, Margam; John, Yong Ming Shyan

    2004-01-01

    Magnesium alloys are being extensively used in weight-saving applications and as a potential replacement for plastics in electronic and computer applications. However, processing of magnesium has always been a challenge for manufacturing industries owing to their high brittleness despite their good EMI shielding property and high specific strength. Despite these advantages, they are limited by their processability. The present work aims to evaluate lower temperature formability of magnesium alloys. Three different materials were selected for axisymmetric extrusion tests, namely AZ31, AZ61 and the forging alloy, ZK 60. To establish the size and capacity of the press required to perform these forming trials and to know the formability, simulation using finite element analysis was carried on a representative material AZ31 using the properties established based on earlier work. A die set with a die shoe was designed to perform the forward extrusion trials. The area reduction ratio for forward extrusion was fixed at 41% for the die design and simulation. The maximum strain is given as ln(A o /A f ) ∼ 0.88 in the case of forward extrusion. The temperature was varied with a temperature controller built in-house from room temperature (RT) to 300 deg.C. However, the results provided below only include the tests carried out at RT, 100, 150, 175 and 200 deg.C. Although the forming trials were successful above 200 deg.C, there was difficulty in removing the specimens from the die cavity. Secondly, the process of removing the samples in the case of AZ31 and ZK 60 resulted in cracking, so it was difficult to evaluate the samples and the process. However, AZ61 samples did not show any evidence of crack formation during ejection of the formed sample. Simulation results and experimental trials showed that magnesium (AZ31) could be easily formed at elevated temperatures of 300 deg.C. Though there was a good correlation on the yield point prediction between simulation and

  10. 75 FR 17436 - Certain Aluminum Extrusions From China

    Science.gov (United States)

    2010-04-06

    ... States at less than fair value and alleged to be subsidized by the Government of China. Unless the... response to a petition filed on March 31, 2010, by the Aluminum Extrusions Fair Trade Committee... presentation at the conference. A nonparty who has testimony that may aid the Commission's deliberations may...

  11. Acid-extrusion from tissue: the interplay between membrane transporters and pH buffers.

    Science.gov (United States)

    Hulikova, Alzbeta; Harris, Adrian L; Vaughan-Jones, Richard D; Swietach, Pawel

    2012-01-01

    The acid-base balance of cells is related to the concentration of free H⁺ ions. These are highly reactive, and their intracellular concentration must be regulated to avoid detrimental effects to the cell. H⁺ ion dynamics are influenced by binding to chelator substances ('buffering'), and by the production, diffusion and membrane-transport of free H⁺ ions or of the H⁺-bound chelators. Intracellular pH (pHi) regulation aims to balance this system of diffusion-reaction-transport processes at a favourable steady-state pHi. The ability of cells to regulate pHi may set a limit to tissue growth and can be subject to selection pressures. Cancer cells have been postulated to respond favourably to such selection pressures by evolving a better means of pHi regulation. A particularly important feature of tumour pHi regulation is acid-extrusion, which involves H⁺-extrusion and HCO₃⁻-uptake by membrane-bound transporter-proteins. Extracellular CO₂/HCO₃⁻ buffer facilitates these membrane-transport processes. As a mobile pH-buffer, CO₂/HCO₃⁻ protects the extracellular space from excessive acidification that could otherwise inhibit further acid-extrusion. CO₂/HCO₃⁻ also provides substrate for HCO₃⁻-transporters. However, the inherently slow reaction kinetics of CO₂/HCO₃⁻ can be rate-limiting for acid-extrusion. To circumvent this, cells can express extracellular-facing carbonic anhydrase enzymes to accelerate the attainment of equilibrium between CO₂, HCO₃⁻ and H⁺. The acid-extrusion apparatus has been proposed as a target for anti-cancer therapy. The major targets include H⁺ pumps, Na⁺/H⁺ exchangers and carbonic anhydrases. The effectiveness of such therapy will depend on the correct identification of rate-limiting steps in pHi regulation in a specific type of cancer.

  12. Consensus Control Design for 360 MN Extrusion Machine Producing Process

    Directory of Open Access Journals (Sweden)

    Chao Wang

    2014-01-01

    Full Text Available This paper mainly addresses the issue of 360 MN extrusion machine and focuses on the stabilization control of main table attitude. We will first introduce the problem and then model the extrusion machine. As the machine is a multi-input multioutput (MIMO and strong coupling system, it is challenging to apply existing control theory to design a controller to stabilize the main table attitude. Motivated by recent research in the field of multiagent systems, we design a consensus control protocol for our system and derive our convergence conditions based directly on Routh stability criterion. The advantages of the design are also demonstrated by numerical simulation.

  13. Anomalous growth of whisker-like bismuth-tin extrusions from tin-enriched tin-Bi deposits

    International Nuclear Information System (INIS)

    Hu, C.-C.; Tsai, Y.-D.; Lin, C.-C.; Lee, G.-L.; Chen, S.-W.; Lee, T.-C.; Wen, T.-C.

    2009-01-01

    This article shows the first finding that the anomalous growth of Bi-Sn extrusions from tin-enriched alloys (Sn-xBi with x between 20 and 10 wt.%) can be induced by post-plating annealing in N 2 between 145 and 260 deg. C for 10 min although metal whiskers were commonly formed on the surface of pure metals or alloys of the enriched component. From SEM observations, very similar to Sn whiskers, Bi-Sn extrusions vary in size, shape, length, and diameter with changing the annealing temperature, which are highly important in regarding the potential for failure of electronic products. Annealing resulting in thermal expansion of Sn grains is believed to squeeze the Bi-Sn alloys with relatively low melting points to form whisker-like extrusions although the exact mechanism is unclear

  14. Main and interaction effects of extrusion temperature and usage ...

    African Journals Online (AJOL)

    ali

    2012-10-30

    Oct 30, 2012 ... The main and interaction effects of three extrusion ... oil extraction and allow the use of a homegrown protein supplement in the .... Statistical analysis. The main and .... acceptable level of antitrypsin factor is 4 mg/g; this level.

  15. Rotations and angular momentum

    International Nuclear Information System (INIS)

    Nyborg, P.; Froyland, J.

    1979-01-01

    This paper is devoted to the analysis of rotational invariance and the properties of angular momentum in quantum mechanics. In particular, the problem of addition of angular momenta is treated in detail, and tables of Clebsch-Gordan coefficients are included

  16. Periodontal healing complications following extrusive and lateral luxation in the permanent dentition: a longitudinal cohort study

    DEFF Research Database (Denmark)

    Hermann, Nuno Vibe; Lauridsen, Eva Fejerskov; Christensen, Søren Steno Ahrensburg

    2012-01-01

    To analyze the risk of tooth loss and complications in periodontal ligament (PDL) healing following extrusive and lateral luxation in the permanent dentition.......To analyze the risk of tooth loss and complications in periodontal ligament (PDL) healing following extrusive and lateral luxation in the permanent dentition....

  17. Photoelectron angular distribution from free SiO2 nanoparticles as a probe of elastic electron scattering.

    Science.gov (United States)

    Antonsson, E; Langer, B; Halfpap, I; Gottwald, J; Rühl, E

    2017-06-28

    In order to gain quantitative information on the surface composition of nanoparticles from X-ray photoelectron spectroscopy, a detailed understanding of photoelectron transport phenomena in these samples is needed. Theoretical results on the elastic and inelastic scattering have been reported, but a rigorous experimental verification is lacking. We report in this work on the photoelectron angular distribution from free SiO 2 nanoparticles (d = 122 ± 9 nm) after ionization by soft X-rays above the Si 2p and O 1s absorption edges, which gives insight into the relative importance of elastic and inelastic scattering channels in the sample particles. The photoelectron angular anisotropy is found to be lower for photoemission from SiO 2 nanoparticles than that expected from the theoretical values for the isolated Si and O atoms in the photoelectron kinetic energy range 20-380 eV. The reduced angular anisotropy is explained by elastic scattering of the outgoing photoelectrons from neighboring atoms, smearing out the atomic distribution. Photoelectron angular distributions yield detailed information on photoelectron elastic scattering processes allowing for a quantification of the number of elastic scattering events the photoelectrons have undergone prior to leaving the sample. The interpretation of the experimental photoelectron angular distributions is complemented by Monte Carlo simulations, which take inelastic and elastic photoelectron scattering into account using theoretical values for the scattering cross sections. The results of the simulations reproduce the experimental photoelectron angular distributions and provide further support for the assignment that elastic and inelastic electron scattering processes need to be considered.

  18. Microstructure of titanium deformed by warm extrusion with forward- backward rotating die

    International Nuclear Information System (INIS)

    Sztwiertnia, K; Morawiec, A; Bieda, M; Kawałko, J

    2014-01-01

    The principal KoBo device is a press with a forward-backward rotating die, enabling the extrusion of ingots under conditions of constant destabilization of their substructure. Polycrystalline grade 2 titanium was subjected to warm KoBo type extrusion. Microstructure of the material was investigated by means of Electron Backscatter Diffraction (EBSD) in the scanning electron microscope. It clearly shows deformation-induced grain fragmentation. The EBSD maps reveal heterogeneous microstructure built of ribbons curled about the extrusion direction (ED) and some equiaxed or cigar-like grains. Sizes of grains vary in the range 70 – 1500 nm for the minor axis and 350 – 20000 nm for the major axis. The material has a relatively sharp nearly axial texture with the <0001> axis perpendicular to ED. In misorientation angle distribution, besides the peak at low angle boundaries, there are three other peaks at about: 29.7deg, 89.7deg and 93.2deg. They do not correspond to any twin boundaries or low Σ coincidence site lattice misorientations

  19. Growth of extrusions in localized cyclic plastic straining

    Czech Academy of Sciences Publication Activity Database

    Polák, Jaroslav; Sauzay, M.

    2009-01-01

    Roč. 500, č. 1-2 (2009), s. 122-129 ISSN 0921-5093 R&D Projects: GA ČR GA101/07/1500 Institutional research plan: CEZ:AV0Z20410507 Keywords : extrusion * strain localization * persistent slip band * vacancy Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.901, year: 2009

  20. Microstructural modelling and lubrication study during zirconium alloy hot extrusion

    International Nuclear Information System (INIS)

    Gaudout, B.

    2009-01-01

    Using torsion tests (with strain rate jumps) and an experimental hot mini-extrusion apparatus, several samples zirconium alloy have been deformed: Zircaloy-4 (high α range) and Zr-1Nb (α + β domain). The fragmentation of the microstructure and post-dynamic grain growth have been examined. The main difference between these two alloys is that Zr-1Nb does not show grain growth during a heat treatment within the α + β domain after hot deformation. The recrystallization volume fraction has been measured on extruded samples with or without heat treatment. These rheological and microstructural data have been used to determine the parameters of a microstructural model including: a work-hardening model (Laaasraoui/Jonas), a continuous dynamic recrystallization model (Gourdet/Montheillet) and a grain growth model. This model leads to a good prediction of recrystallization volume fraction for Zircaloy-4 extrusion. However, the Zr-1Nb model cannot be validated because of the difficulty to observe deformed microstructures. Extrusion process is lubricated with a solid film. Trapping tests show that this lubricant is thermoviscoplastic. Friction along the container and several observations show the lubrication is not realized by a continuous film. Indeed, the heterogeneousness of deformation of these alloys causes a rupture of the lubricant film. Experiments and numerical simulations show that the radial gradient of axial displacement is affected by friction but also by stress softening of the alloys. (author)

  1. Locking of intrinsic angular momentum in collision complexes

    International Nuclear Information System (INIS)

    Berengolts, Alexander.

    1995-04-01

    A concept of locking of the intrinsic angular momentum of a fragment of a collision complex to a body-fixed axis is widely used in the description of heavy-particle dynamics. The aim of this work is to provide a semiclassical description of the locking phenomenon which occur in diatomic and three atomic collision complexes. The first part of this work is devoted to the semiclassical study of the locking of the electronic angular momentum that occurs in slow collisions of two atoms, one in the spherically symmetric state and the other in state with j= 1. Here we calculate explicitly the complete locking matrix for different types of interatomic interactions. The elements of this matrix directly enter into the semiclassical expression for the different cross sections of polarized atoms. Limitations to the notion of the the locking radius and slipping probability are discussed in connection with the steepness of the interaction. Numerical calculations confirm analytical result: the optimal criterion for determination of the locking radius is a condition for the accumulated phase difference between two molecular states. Analytical expressions are suggested for the locking angle and the slipping probability. Implication of the locking approximation for calculation of the quasiclassical scattering matrix is discussed. The second part considers the locking of the rotational angular momentum of a diatom in the decomposition of a triatomic complexes. We discuss here cases J = 1,2,3 and 4, but restrict ourselves to calculation of the so-called dynamic orientation of the diatomic fragment. The letter represents one of the characteristics of the locking matrix which in principle can be measured experimentally. The orientation is created as a result of the interplay between the adiabatic interaction in the atom- diatom exit channel and the rotationally non adiabatic coupling in the perturbed rotor region

  2. A proposed measurement of optical orbital and spin angular momentum and its implications for photon angular momentum

    Science.gov (United States)

    Leader, Elliot

    2018-04-01

    The expression for the total angular momentum carried by a laser optical vortex beam, splits, in the paraxial approximation, into two terms which seem to represent orbital and spin angular momentum respectively. There are, however, two very different competing versions of the formula for the spin angular momentum, one based on the use of the Poynting vector, as in classical electrodynamics, the other related to the canonical expression for the angular momentum which occurs in Quantum Electrodynamics. I analyze the possibility that a sufficiently sensitive optical measurement could decide which of these corresponds to the actual physical angular momentum carried by the beam.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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 Ti 2 Cu particle significantly. Ti-Cu(E) alloys exhibited higher hardness and compressive yield strength than Ti-Cu(S) alloys due to the fine grain and Ti 2 Cu 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. - Highlights: • Hot extrusion refined the grain size and Ti 2 Cu phase significantly. • Hot extrusion increased the mechanical properties and the corrosion resistance. • The antibacterial properties was not affected by the hot process.

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

    Science.gov (United States)

    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

  5. Role of lipids in the extrusion cooking processes

    Directory of Open Access Journals (Sweden)

    Berghofe, E.

    2000-04-01

    Full Text Available Extrusion is a versatile and very efficient technology that is widely used in food and feed processing. The cooking extruders have found many applications, which include: breakfast cereals, snack foods, other cereal based products, pet food and aquatic foods, texturized vegetable proteins, confectionery products, chemical and biochemical reactions, and oil extraction. Lipids are components that play an important role in most of the extrusion cooking processes. They can act as plastificizers or emulsifiers, and affect more significantly texture and stickiness of the extrudate. This paper reviews effect of oils and other lipids reactions during extrusion cooking as well as the effects of amylase-lipid complexation on extrudate quality.La extrusión es, en general, una tecnología versátil y muy eficiente, que se aplica ampliamente en la elaboración de alimentos y piensos. Los equipos de cocción-extrusión tienen numerosas aplicaciones, entre las que pueden incluirse: los cereales de desayuno listos para comer, los aperitivos, diferentes productos basados en cereales, los piensos para animales domésticos y peces, proteínas vegetales texturizadas, productos de pastelería, reacciones químicas y bioquímicas, y la extracción de aceites. Los lípidos son componentes que juegan un papel importante en la mayoría de los procesos de cocción-extrusión. Pueden actuar como plastificantes o como emulsionantes, suministrando lubricación. En este artículo se revisan con detalle los efectos de las reacciones de los aceites y otros lípidos durante el proceso de cocción-extrucción así como el efecto de la formación de complejos amilasa-lípidos sobre la calidad de los extrudados.

  6. A measurement by BOOMERANG of multiple peaks in the angular power spectrum of the cosmic microwave background

    Science.gov (United States)

    Netterfield, C. B.; Ade, P. A. R.; Bock, J. J.; Bond, J. R.; Borrill, J.; Boscaleri, A.; Coble, K.; Contaldi, C. R.; Crill, B. P.; Bernardis, P. de; hide

    2001-01-01

    This paper presents a measurement of the angular power spectrum of the Cosmic Microwave Background from l = 75 to l = 1025 (10' to 5 degrees) from a combined analysis of four 150 GHz channels in the BOOMERANG experiment. The spectrum contains multiple peaks and minima, as predicted by standard adiabatic-inflationary models in which the primordial plasma undergoes acoustic oscillations.

  7. Modelling of anisotropy for Al-Li 2099 T83 extrusions and effect of precipitate density

    International Nuclear Information System (INIS)

    Bois-Brochu, Alexandre; Blais, Carl; Tchitembo Goma, Franck Armel; Larouche, Daniel

    2016-01-01

    The development of aluminum-lithium alloys for aerospace applications requires a thorough understanding of how processing and product geometry impact their microstructure, texture and mechanical properties. The anisotropy of the mechanical properties is in part related to the deformation texture formed during thermo-mechanical processing. In this study, two different extrusions of Al-Li 2099 T83 were characterized, a cylindrical extrusion and an integrally stiffened panel (ISP). A model is proposed to predict mechanical properties and their anisotropy as a function of the <111> fiber texture. Furthermore, the volume fraction of precipitates was measured in zones of high anisotropy (cylindrical extrusion) and low anisotropy (ISP). Results show that there is no significant difference between the two parts concerning volume fraction of precipitates.

  8. Modelling of anisotropy for Al-Li 2099 T83 extrusions and effect of precipitate density

    Energy Technology Data Exchange (ETDEWEB)

    Bois-Brochu, Alexandre, E-mail: Alexandre.Bois-Brochu.1@ulaval.ca; Blais, Carl, E-mail: Carl.Blais@gmn.ulaval.ca; Tchitembo Goma, Franck Armel, E-mail: Franck-Armel.Tchitembo-Goma.1@ulaval.ca; Larouche, Daniel, E-mail: Daniel.Larouche@gmn.ulaval.ca

    2016-09-15

    The development of aluminum-lithium alloys for aerospace applications requires a thorough understanding of how processing and product geometry impact their microstructure, texture and mechanical properties. The anisotropy of the mechanical properties is in part related to the deformation texture formed during thermo-mechanical processing. In this study, two different extrusions of Al-Li 2099 T83 were characterized, a cylindrical extrusion and an integrally stiffened panel (ISP). A model is proposed to predict mechanical properties and their anisotropy as a function of the <111> fiber texture. Furthermore, the volume fraction of precipitates was measured in zones of high anisotropy (cylindrical extrusion) and low anisotropy (ISP). Results show that there is no significant difference between the two parts concerning volume fraction of precipitates.

  9. Incorporation of ladle furnace slag in ceramic formulations: study of extrusion zones

    International Nuclear Information System (INIS)

    Feitosa, E.F.; Santana, C.M.; Luna, D.S.; Santos, D.M.S.; Silva, G.S.; Noleto, L.T.; Almeida, N.C.; Rabelo, A.A.; Fagury Neto, E.

    2016-01-01

    This study aimed to investigate the effect of incorporation of ladle furnace slag (LFS) in two clays with higher and lower plasticity, used for the manufacture of structural ceramics. The LFS from a local steel making plant was added to ceramic compositions in proportions of 8 %, 14 % and 16 %. The formulations were tested in appropriate equipment that measures the liquid limit and plastic limit. The property examined was the plasticity index, in order to make a study of the extrusion zones. Results showed that the addition of slag into clay mixtures alters the plasticity; however, the extrusion process was not hampered. (author)

  10. Development of a high speed extrusion concept using a floating screw sleeve for solid-melt-separation

    Science.gov (United States)

    Karrenberg, Gregor; Wortberg, Johannes

    2015-05-01

    The High-Speed-S-Truder with floating screw sleeve is an alternative extrusion concept with solid-melt-separation. A fairly conventional 35 mm screw with a length of 21 D, which is accelerated by a 75 kW gearless, water cooled synchronous drive, conveys the resin into a 60 mm screw sleeve with a length of 10 D. Inside the sleeve the material is plasticizied and discharged into the outer screw channel of the sleeve through radial bores. Only the solid bed remains inside. The development of a melt pool - and thus a decrease of the plasticizing capacity - is avoided. The sleeve is rotated by drag forces only (approximately 10 - 15 % of the screw speed). Due to the low speed of the screw sleeve molten material is conveyed to a 4 D Dynamic Mixing Ring in a gentle manner. The DMRs floating ring and the screw sleeve are directly coupled. The granules in the screw channel are stopped by a barrier on the screw in front of the mixing device. So nearly no unmelted material can pass the system. For temperature management in the plastification and mixing zone a 3-zone heating/air-cooling system is used. Various kinds of experiments with the High-Speed S-Truder were conducted. Reachable throughputs with different types of material (LDPE, LLDPE, PP, PS) have been tested. Also three screw geometries, which are mainly varying in the channel depth, were compared. Experimental results and theoretical background will be described in this paper.

  11. Top quark polarization in t-channel single top-quark events with the ATLAS detector

    CERN Document Server

    Chitishvili, Mariam

    2017-01-01

    This summary presents the measurement of the top‐quark polarization in t-channel single top quarks with the ATLAS detector at the LHC. Monte Carlo simulated events are used. Selected events contain one lepton, large missing transverse momentum and exactly two jets, with one of them identified as b-jet. Selection cuts are used to identify the t-channel topology at reconstruction level. The polarization is measured, from an asymmetry in an angular distribution, at parton level by correcting the reconstructed angular distribution for detector effects. This project provides an overview on how a "standard" physics analysis is performed within ATLAS. The analysis is performed in ROOT. Simulation data is reconstructed to perform an unfolded measurement of a given property of a fundamental particle within the Standard Model. Finally results are compared with theoretical predictions.

  12. High-temperature extrusion behavior of a superplastic zirconia-based ceramic

    International Nuclear Information System (INIS)

    Kellett, B.J.; Carry, C.; Mocellin, A.

    1990-01-01

    Workability of 3-mol%-yttria-stabilized tetragonal ZrO 2 has been gauged through a series of extrusion experiments performed under vacuum with graphite dies at 1500 degrees C and 35 MPa piston stress. It is shown that dense and smooth extrustions can be obtained from solid billets when graphite paper is used as a lubricant. Sigmoidal dies and conical dies with cone angles of 18.4 degrees, 26.6 degrees, and 45 degrees and diameter ratios of 1.5, 2, and 3 were used to explore extrusion behavior. Observed piston velocities correspond to what may be predicted from the experimental uniaxial constitutive creep equation and a simple slab analysis. A precise analysis, however, is not attempted because of lack of steady-state behavior of the material itself

  13. Accretion torques due to three-dimensional channelled flows in magnetic cataclysmic variables

    International Nuclear Information System (INIS)

    Campbell, C.G.

    1986-01-01

    Angular momentum transfer due to three-dimensional magnetically channelled accretion flows in cataclysmic binaries is considered. The white dwarf experiences a torque due to the twist in that part of its magnetic field which interacts with the accretion stream. The channelling process can also enhance angular momentum exchange between the stream and the orbit by increasing the gravitational torques. The components of the accretion torque are calculated for an arbitrary static magnetic orientation of the white dwarf, and their variation with orientation is presented. For high inclinations of the accreting pole to the orbital plane the component of the accretion torque parallel to this plane can be comparable to its perpendicular component. It is shown that the parallel component of the torque is still significant relative to the perpendicular component if material links to the white dwarf's magnetic field well away from the L 1 region. (author)

  14. AngularJS Performance: A Survey Study

    OpenAIRE

    Ramos, Miguel; Valente, Marco Tulio; Terra, Ricardo

    2017-01-01

    AngularJS is a popular JavaScript MVC-based framework to construct single-page web applications. In this paper, we report the results of a survey with 95 professional developers about performance issues of AngularJS applications. We report common practices followed by developers to avoid performance problems (e.g., use of third-party or custom components), the general causes of performance problems in AngularJS applications (e.g., inadequate architecture decisions taken by AngularJS users), a...

  15. Angular Positioning Sensor for Space Mechanisms

    Science.gov (United States)

    Steiner, Nicolas; Chapuis, Dominique

    2013-09-01

    Angular position sensors are used on various rotating mechanisms such as solar array drive mechanisms, antenna pointing mechanisms, scientific instruments, motors or actuators.Now a days, potentiometers and encoders are mainly used for angular measurement purposes. Both of them have their own pros and cons.As alternative, Ruag Space Switzerland Nyon (RSSN) is developing and qualifying two innovative technologies of angular position sensors which offer easy implementation, medium to very high lifetime and high flexibility with regards to the output signal shape/type.The Brushed angular position sensor uses space qualified processes which are already flying on RSSN's sliprings for many years. A large variety of output signal shape can be implemented to fulfill customer requirements (digital, analog, customized, etc.).The contactless angular position sensor consists in a new radiation hard Application Specific Integrated Circuit (ASIC) based on the Hall effect and providing the angular position without complex processing algorithm.

  16. Apical Extrusion of Debris Produced during Continuous Rotating and Reciprocating Motion

    Directory of Open Access Journals (Sweden)

    Giselle Nevares

    2015-01-01

    Full Text Available This study aimed to analyse and compare apical extrusion of debris in canals instrumented with systems used in reciprocating and continuous motion. Sixty mandibular premolars were randomly divided into 3 groups (n=20: the Reciproc (REC, WaveOne (WO, and HyFlex CM (HYF groups. One Eppendorf tube per tooth was weighed in advance on an analytical balance. The root canals were instrumented according to the manufacturer’s instructions, and standardised irrigation with 2.5% sodium hypochlorite was performed to a total volume of 9 mL. After instrumentation, the teeth were removed from the Eppendorf tubes and incubated at 37°C for 15 days to evaporate the liquid. The tubes were weighed again, and the difference between the initial and final weight was calculated to determine the weight of the debris. The data were statistically analysed using the Shapiro-Wilk, Wilcoxon, and Mann-Whitney tests (α=5%. All systems resulted in the apical extrusion of debris. Reciproc produced significantly more debris than WaveOne (p<0.05, and both systems produced a greater apical extrusion of debris than HyFlex CM (p<0.001. Cross section and motion influenced the results, despite tip standardization.

  17. Instant AngularJS starter

    CERN Document Server

    Menard, Dan

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. This book is written in an easytoread style, with a strong emphasis on realworld, practical examples. Stepbystep explanations are provided for performing important tasks.This book is for web developers familiar with JavascriptIt doesn't cover the history of AngularJS, and it's not a pitch to convince you that AngularJS is the best framework on the entire web. It's a guide to help you learn everything you need to know about AngularJS in as few pa

  18. AngularJS testing cookbook

    CERN Document Server

    Bailey, Simon

    2015-01-01

    This book is intended for developers who have an understanding of the basic principles behind both AngularJS and test-driven development. You, as a developer, are interested in eliminating the fear related to either introducing tests to an existing codebase or starting out testing on a fresh AngularJS application. If you're a team leader or part of a QA team with the responsibility of ensuring full test coverage of an application, then this book is ideal for you to comprehend the full testing scope required by your developers. Whether you're new to or are well versed with AngularJS, this book

  19. The extrusion test and sensory perception revisited: Some comments on generality and the effect of measurement temperature.

    Science.gov (United States)

    Brenner, Tom; Tomczyńska-Mleko, Marta; Mleko, Stanisław; Nishinari, Katsuyoshi

    2017-12-01

    Relations between sensory perception, extrusion and fracture in shear, extension and compression are examined. Gelatin-based gels are perceived as less firm and less hard than expected based on their mechanical properties compared to polysaccharide gels that have the same mechanical properties at room temperature but melt well above body temperature, underlying the importance of the measurement temperature for gels that melt during mastication. Correlations between parameters from extrusion and compression, extension and shear are verified using mixed polysaccharide gels. We previously reported a high correlation between several sensory attributes and parameters from an extrusion test. The extrusion test showed the most robust correlation, and could be used to assess samples at both extremes of the texture range with respect to elasticity, for example, both samples that could not be extended as their very low elasticity led to their fracture during handling, as well as samples that could not be fractured in compression. Here, we reexamine the validity of the relations reported. We demonstrate the generality of the relations between large deformation tests and extrusion, but the findings underscore the need to take into account the measurement temperature for samples that melt during mastication when correlating instrumental parameters with sensory perception. © 2017 Wiley Periodicals, Inc.

  20. Influence of Extrusion Temperature on the Aging Behavior and Mechanical Properties of an AA6060 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Nadja Berndt

    2018-01-01

    Full Text Available Processing of AA6060 aluminum alloys for semi-products usually includes hot extrusion with subsequent artificial aging for several hours. Processing below the recrystallization temperature allows for an increased strength at a significantly reduced annealing time by combining strain hardening and precipitation hardening. In this study, we investigate the potential of cold and warm extrusion as alternative processing routes for high strength aluminum semi-products. Cast billets of the age hardening aluminum alloy AA6060 were solution annealed and then extruded at room temperature, 120 or 170 °C, followed by an aging treatment. Electron microscopy and mechanical testing were performed on the as-extruded as well as the annealed materials to characterize the resulting microstructural features and mechanical properties. All of the extruded profiles exhibit similar, strongly graded microstructures. The strain gradients and the varying extrusion temperatures lead to different stages of dynamic precipitation in the as-extruded materials, which significantly alter the subsequent aging behavior and mechanical properties. The experimental results demonstrate that extrusion below recrystallization temperature allows for high strength at a massively reduced aging time due to dynamic precipitation and/or accelerated precipitation kinetics. The highest strength and ductility were achieved by extrusion at 120 °C and subsequent short-time aging.

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

    African Journals Online (AJOL)

    Aynadis

    metabolites which can be observed on food stuffs or ... Extrusion cooking technologies are used to ..... effective interaction to reduce aflatoxin B1in the ..... Drug. Administration, “Guidance for industry: Action levels for poisonous or deleterious.

  2. Strain detection in crystalline heterostructures using bidimensional blocking patterns of channelled particles

    Science.gov (United States)

    Redondo-Cubero, A.; David-Bosne, E.; Wahl, U.; Miranda, P.; da Silva, M. R.; Correia, J. G.; Lorenz, K.

    2018-03-01

    Strain is a critical parameter affecting the growth and the performance of many semiconductor systems but, at the same time, the accurate determination of strain profiles in heterostructures can be challenging, especially at the nanoscale. Ion channelling/blocking is a powerful technique for the detection of the strain state of thin films, normally carried out through angular scans with conventional particle detectors. Here we report the novel application of position sensitive detectors for the evaluation of the strain in a series of AlInN/GaN heterostructures with different compositions and thicknesses. The tetragonal strain is varied from compressive to tensile and analysed through bidimensional blocking patterns. The results demonstrate that strain can be correctly quantified when compared to Monte Carlo channelling simulations, which are essential because of the presence of ion steering effects at the interface between the layer and the substrate. Despite this physical limitation caused by ion steering, our results show that full bidimensional patterns can be applied to detect fingerprints and enhance the accuracy for most critical cases, in which the angular shift associated to the lattice distortion is below the critical angle for channelling.

  3. A Waveguide Antenna with an Extended Angular Range for Remote Steering of Wave-Beam Direction

    Science.gov (United States)

    Sobolev, D. I.; Denisov, G. G.

    2018-03-01

    A new method for increasing the angular range of a waveguide antenna for remote steering of the wave-beam direction in thermonuclear-fusion experimental setups with plasma magnetic confinement is proposed. Characteristics for large beam inclination angles can be improved using the synthesized nonuniform waveguide profile. For small angles, the characteristics remain invariable, the waveguide profile differs only slightly from the regular shape, and can be fit to limited waveguide-channel sizes.

  4. Coupled channel analysis of s-wave ππ and K anti-K photoproduction

    International Nuclear Information System (INIS)

    Chueng-Ryong Ji; Szczepaniak, A.; Kaminski, R.; Lesniak, L.; Williams, R.

    1997-10-01

    We present a coupled channel partial wave analysis of non-diffractive S-wave π + π - and K + K - photoproduction focusing on the K anti-K threshold. Final state interactions are included. We calculate total cross sections, angular and effective mass distributions in both ππ and K anti-K channels. Our results indicate that these processes are experimentally measurable and valuable information on the f 0 (980) resonance structure can be obtained. (author)

  5. Oriented Structure of Pentablock Copolymers Induced by Solution Extrusion

    Science.gov (United States)

    Harada, Tamotsu; Bates, Frank S.; Lodge, Timothy P.

    2002-03-01

    Highly oriented structure of a poly(styrene-co-butadiene) pentablock copolymer (Mw; 104,700 g/mol, weight percentage of polybutadiene blocks; 29 wt of concentrated solutions. The pentablock copolymer was dissolved into mixtures of toluene and heptane, and the polymer concentration ranged from 40 wt extrusion, the pentablock copolymer was solidified either by coagulation in methanol or by evaporation of the solvent. Interestingly, a highly oriented lamellar structure was confirmed through the small angle X-ray scattering over a specific range of heptane composition, which is a good solvent for polybutadiene, although the hexagonal cylinder morphology was identified for the melt sample. The transition from the oriented lamellar to highly oriented cylinder structure was observed by annealing the samples at temperatures above the glass transition temperature of polystyrene. Moreover, a transition from parallel to perpendicular orientation in the lamellar state was observed with an increase of the extrusion shear rate. A comparison between pentablock and triblock copolymers will be also discussed.

  6. Phenomenological analisis of the p-even- and p,odd-angular asimmetry of alpha particles in the 10B(n, α)7Li reaction with thermal polarized neutrons

    International Nuclear Information System (INIS)

    Rzhevskij, E.S.

    1983-01-01

    The formalism for multilevel phenomfor munological analysis of angular asymmetry of alpha-particles escape from compound-nuclei in reactions induced by thermal polarized neutrons is suggested. The formalism is based on R-matrix theory of nuclear reactions. The connection of problems of angular correlations description with those of light nuclei structure is shown. The problems related to the selection of compound-resonance parameters, determination of alpha-cluster states, estimation of the role of these or those compound-resonances in neutron and alpha-particle channels are discussed. An explanation is given to the observed in the experiment p-even left/right angular asymmetry of alpha-particles. The values of p-odd angular correlations, the measurements of which are continued, are estimated

  7. Efeito de parâmetros de extrusão na cor E propriedades de pasta da farinha de mandioquinha-salsa (Arracacia xanthorrhiza Effect of extrusion parameters on color and pasting properties of peruvian carrot flour (Arracacia xanthorrhiza

    Directory of Open Access Journals (Sweden)

    Bruna Menegassi

    2007-12-01

    Full Text Available Processou-se neste trabalho a farinha de mandioquinha-salsa (Arracacia xanthorrhiza Bancr. em uma linha de extrusão (mono rosca variando as condições operacionais: umidade da farinha (11-19%, temperatura de extrusão (86-154ºC e taxa de rotação da rosca (136-272rpm. Os parâmetros de cor analisados foram luminosidade (L* e os componentes de cromaticidade a* e b*. Os parâmetros de propriedade de pasta analisados foram viscosidade inicial, pico de viscosidade, quebra de viscosidade, tendência a retrogradação e viscosidade final. Os resultados obtidos mostraram que a umidade da matéria-prima interferiu nos componentes de cor das farinhas com efeito significativo sobre a luminosidade e croma a*, e a temperatura interferiu no croma b* . Quanto ao efeito dos parâmetros de processo sobre as propriedades de pasta, a umidade interferiu nas viscosidades inicial e final dos produtos, pico e quebra de viscosidade, enquanto a temperatura de extrusão e a rotação da rosca tiveram influência sobre a tendência a retrogradação e viscosidade final dos produtos.In this work peruvian carrot flour (Arracacia xanthorrhiza Bancr. was processed in a single screw extruder at different moisture contents (11-19%, extrusion temperature (86-154ºC and screw speed (136-272rpm. The parameters L*, a* and b* of color were analyzed in extruded flours. The viscosity related parameters determined include initial viscosity, viscosity peak, breakdown, setback and final viscosity. The results showed effect of feed moisture on flour color (L* and a* and the extrusion temperature influenced b*. Moisture content of the feed had effect on initial and final viscosity, viscosity peak and breakdown. Extrusion temperature and screw speed had effect on final viscosity and setback.

  8. Dental extrusion with orthodontic miniscrew anchorage: a case report describing a modified method.

    Science.gov (United States)

    Horliana, Ricardo Fidos; Horliana, Anna Carolina Ratto Tempestini; Wuo, Alexandre do Vale; Perez, Flávio Eduardo Guillin; Abrão, Jorge

    2015-01-01

    In recent years, the skeletal anchorage through miniscrews has expanded the treatment options in orthodontics (Yamaguchi et al., 2012). We hereby present a modified method for tooth extrusion for cases where crown-lengthening surgery is contraindicated for aesthetic reasons. This modified method uses three orthodontic appliances: a mini-implant, an orthodontic wire, and a bracket. The aim of this case report was to increase the length of the clinical crown of a fractured tooth (tooth 23) by means of an orthodontic extrusion with the modified method of Roth and Diedrich.

  9. Evaluation of hardening and softening behaviors in Zn–21Al–2Cu alloy processed by equal channel angular pressing

    Directory of Open Access Journals (Sweden)

    José Luis Hernández-Rivera

    2017-10-01

    Full Text Available The microstructural evolution of as-cast and homogenized Zn–21Al–2Cu samples after two and six passes in an equal channel angular pressing (ECAP at room temperature was reported. A homogenization treatment for 24 h at 350 °C was applied to the as-cast samples followed by deformation. An annealing heat treatment was performed on all samples after the ECAP process. Our results showed that the homogenized and deformed samples displayed a uniform fine-grained microstructure after annealing, while as-cast samples without homogenization treatment presented only some regions of fine-grained microstructure. The level of microsegregation was higher in the as-cast samples as compared to the homogenized ones even after annealing. Vickers microhardness measurement on samples after deformation is smaller than the original material indicating a softening. However, after the annealing treatment, the microhardness increased, indicating that there was a slight hardening of the material. Keywords: Severe plastic deformation, ECAP, Work softening, Annealing, Hardening, Fine grain

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

    Science.gov (United States)

    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.

  11. Variation in angular velocity and angular acceleration of a particle in rectilinear motion

    International Nuclear Information System (INIS)

    Mashood, K K; Singh, V A

    2012-01-01

    We discuss the angular velocity and angular acceleration associated with a particle in rectilinear motion with constant acceleration. The discussion was motivated by an observation that students and even teachers have difficulty in ascribing rotational motion concepts to a particle when the trajectory is a straight line. We present some details of our observations. A formal derivation of ω and α is presented which reveals ‘surprising’ and non-intuitive aspects, namely non-monotonic behaviour with an associated extremum. The special case of constant velocity is studied and we find that angular acceleration associated with it also has an extremum. We discuss a plausible source of difficulty. (paper)

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

    Science.gov (United States)

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

    2017-10-01

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

  13. Rapid production of hollow SS316 profiles by extrusion based additive manufacturing

    Science.gov (United States)

    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.

  14. Characterization of ultra-fine grained aluminum produced by accumulative back extrusion (ABE)

    International Nuclear Information System (INIS)

    Alihosseini, H.; Faraji, G.; Dizaji, A.F.; Dehghani, K.

    2012-01-01

    In the present work, the microstructural evolutions and microhardness of AA1050 subjected to one, two and three passes of accumulative back extrusion (ABE) were investigated. The microstructural evolutions were characterized using transmission electron microscopy. The results revealed that applying three passes of accumulative back extrusion led to significant grain refinement. The initial grain size of 47 μm was refined to the grains of 500 nm after three passes of ABE. Increasing the number of passes resulted in more decrease in grain size, better microstructure homogeneity and increase in the microhardness. The cross-section of ABEed specimen consisted of two different zones: (i) shear deformation zone, and (ii) normal deformation zone. The microhardness measurements indicated that the hardness increased from the initial value of 31 Hv to 67 Hv, verifying the significant microstructural refinement via accumulative back extrusion. - Highlights: ► A significant grain refinement can be achieved in AA1050, Al alloy by applying ABE. ► Microstructural homogeneity of ABEed samples increased by increasing the number of ABE cycles. ► A substantial increase in the hardness, from 31 Hv to 67 Hv, was recorded.

  15. Fission fragment angular momentum

    International Nuclear Information System (INIS)

    Frenne, D. De

    1991-01-01

    Most of the energy released in fission is converted into translational kinetic energy of the fragments. The remaining excitation energy will be distributed among neutrons and gammas. An important parameter characterizing the scission configuration is the primary angular momentum of the nascent fragments. Neutron emission is not expected to decrease the spin of the fragments by more than one unit of angular momentum and is as such of less importance in the determination of the initial fragment spins. Gamma emission is a suitable tool in studying initial fragment spins because the emission time, number, energy, and multipolarity of the gammas strongly depend on the value of the primary angular momentum. The main conclusions of experiments on gamma emission were that the initial angular momentum of the fragments is large compared to the ground state spin and oriented perpendicular to the fission axis. Most of the recent information concerning initial fragment spin distributions comes from the measurement of isomeric ratios for isomeric pairs produced in fission. Although in nearly every mass chain isomers are known, only a small number are suitable for initial fission fragment spin studies. Yield and half-life considerations strongly limit the number of candidates. This has the advantage that the behavior of a specific isomeric pair can be investigated for a number of fissioning systems at different excitation energies of the fragments and fissioning nuclei. Because most of the recent information on primary angular momenta comes from measurements of isomeric ratios, the global deexcitation process of the fragments and the calculation of the initial fragment spin distribution from measured isomeric ratios are discussed here. The most important results on primary angular momentum determinations are reviewed and some theoretical approaches are given. 45 refs., 7 figs., 2 tabs

  16. Angular Acceleration without Torque?

    Science.gov (United States)

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  17. Effect of Thermo-extrusion Process Parameters on Selected Quality ...

    African Journals Online (AJOL)

    Effect of Thermo-extrusion Process Parameters on Selected Quality Attributes of Meat Analogue from Mucuna Bean Seed Flour. ... Nigerian Food Journal ... The product functional responses with coefficients of determination (R2) ranging between 0.658 and 0.894 were most affected by changes in barrel temperature and ...

  18. Extrusion Cooking Systems and Textured Vegetable Proteins

    Directory of Open Access Journals (Sweden)

    2015-02-01

    Full Text Available Many fabricated foods are cooked industrially and are given desired textures, shapes, density and rehydration characteristics by an extrusion cooking process. This relatively new process is used in the preparation of “engineered” convenience foods: textured vegetable proteins, breakfast cereals, snacks, infant foods, dry soup mixes, breading, poultry stuffing, croutons, pasta products, beverage powders, hot breakfast gruels, and in the gelatinization of starch or the starchy component of foods.

  19. Angular-momentum transport in nuclear collisions

    International Nuclear Information System (INIS)

    Wolschin, G.; Ayik, S.; Noerenberg, W.

    1978-01-01

    Among the various relaxation processes that can be observed in heavy-ion collisions, the dissipation of relative angular momentum into intrinsic angular momentum of the fragments attracts increasing attention. Here we present a transport theoretical description of angular-momentum and mass transport that allows for a transparent interpretation of the data. (orig.) [de

  20. AngularJS test-driven development

    CERN Document Server

    Chaplin, Tim

    2015-01-01

    This book is for developers who want to learn about AngularJS development by applying testing techniques. You are assumed to have a basic knowledge and understanding of HTML, JavaScript, and AngularJS.

  1. Main and interaction effects of extrusion temperature and usage ...

    African Journals Online (AJOL)

    The extruded full fat soybean (EFFSB) may be used in diet to satisfy the energy and protein requirements of fast growing broiler chickens. The main and interaction effects of three extrusion temperatures and two dietary levels of FFSB were studied on the performance, physiological enzymes and blood metabolites of broiler ...

  2. Rheology and extrusion of low-grade paper and sludge

    Science.gov (United States)

    C. Tim Scott; Stefan Zauscher; Daniel J. Klingenberg

    1999-01-01

    This paper discusses efforts to characterize the rheological properties of pulps that include low-grade wastepapers and papermill sludges to determine their potential for extrusion and conversion into useful products. We investigated apparent changes in viscosity associated with the addition of typical inorganic paper fillers (calcium carbonate, kaolin clay, and...

  3. The (3He,α) reaction mechanism. A study of the angular momentum transfer

    International Nuclear Information System (INIS)

    Guttormsen, M.; Bergholt, L.; Ingebretsen, F.; Loevhoeiden, G.; Messelt, S.; Rekstad, J.; Tveter, T.S.; Helstrup, H.; Thorsteinsen, T.F.

    1994-01-01

    The γ-rays emitted after the 163 Dy( 3 He,αxn) reactions at E( 3 He) = 45 MeV have been measured. The transferred angular momentum in the reaction is deduced from the side-feeding γ-intensities of the ground bands in the residual 162-x Dy isotopes. With decreasing α-energy the average spin transfer increases from similar 5h to similar 11h. The ( 3 He,α) reaction at these energies is dominated by direct processes. Even at the highest spin transfer the contribution from the compound reaction channel is negligible. ((orig.))

  4. Influence of material and solution composition on the extrusion/erosion behaviour of compacted bentonite

    International Nuclear Information System (INIS)

    Schatz, Timothy; Martikainen, Jari; Koskinen, Kari

    2010-01-01

    Document available in extended abstract form only. In principle, in a KBS-3 type repository, the volume of a deposition hole is fixed and the bentonite buffer mass accordingly balanced to lead to the development of a suitable swelling pressure upon saturation. However, fractures intersecting the deposition holes give rise to the possibility that volume constrained conditions do not universally exist. Such fractures may provide pathways for the continued, localised, free swelling of bentonite buffer material. Loss of mass from the deposition hole by extrusion into intersecting fractures may compromise the long-term safety and performance of the buffer component of the engineered barrier system. Furthermore, the continued hydration and expansion of extruded bentonite in these fracture environments could lead to the separation of colloid-sized (or larger) particles by diffusion or shear which may have to be accounted for in possible radionuclide migration scenarios. Geochemical conditions, with respect to both solution and material composition, are considered to play important roles regarding the fracture extrusion/erosion of bentonite buffer material. For example, calcium-montmorillonite exhibits limited free swelling relative to sodium-montmorillonite and the colloidal and rheological properties of montmorillonite dispersions are sensitive to the presence of electrolytes. Insofar as both the buffer material composition (due to ion exchange) and groundwater composition (dilution resulting from infiltration of glacial melt water) are expected to evolve with time, so too might the potential for fracture extrusion/erosion of buffer material vary over time. The hydraulic characteristics of the intersecting fracture are expected to influence the extrusion/erosion process as well. To evaluate the effect of material and solution composition on the potential for extrusion of buffer mass into intersecting fractures, a series of batch experiments were performed. In these

  5. Anoctamin Calcium-Activated Chloride Channels May Modulate Inhibitory Transmission in the Cerebellar Cortex.

    Directory of Open Access Journals (Sweden)

    Weiping Zhang

    Full Text Available Calcium-activated chloride channels of the anoctamin (alias TMEM16 protein family fulfill critical functions in epithelial fluid transport, smooth muscle contraction and sensory signal processing. Little is known, however, about their contribution to information processing in the central nervous system. Here we examined the recent finding that a calcium-dependent chloride conductance impacts on GABAergic synaptic inhibition in Purkinje cells of the cerebellum. We asked whether anoctamin channels may underlie this chloride conductance. We identified two anoctamin channel proteins, ANO1 and ANO2, in the cerebellar cortex. ANO1 was expressed in inhibitory interneurons of the molecular layer and the granule cell layer. Both channels were expressed in Purkinje cells but, while ANO1 appeared to be retained in the cell body, ANO2 was targeted to the dendritic tree. Functional studies confirmed that ANO2 was involved in a calcium-dependent mode of ionic plasticity that reduces the efficacy of GABAergic synapses. ANO2 channels attenuated GABAergic transmission by increasing the postsynaptic chloride concentration, hence reducing the driving force for chloride influx. Our data suggest that ANO2 channels are involved in a Ca2+-dependent regulation of synaptic weight in GABAergic inhibition. Thus, in balance with the chloride extrusion mechanism via the co-transporter KCC2, ANO2 appears to regulate ionic plasticity in the cerebellum.

  6. An upper bound solution for the spread extrusion of elliptical sections

    International Nuclear Information System (INIS)

    Abrinia, K.; Makaremi, M.

    2007-01-01

    The three dimensional problem of extrusion of elliptical sections with side material flow or spread has been formulated using the upper bound theory. The shape of the die for such a process is such that it could allow the material to flow sideways as well as in the forward direction. When flat faced dies are used a deforming region is developed with dead metal zones. Therefore this deforming region has been represented in the formulation based on the definitions of streamlines and stream surfaces. A generalized kinematically admissible velocity field was then derived for this formulation and strain rate components obtained for the upper bound solution. The general formulation for the deforming region and the velocity and strain rate fields allow for the optimization of the upper bound solution so that the nearest geometry of the deforming region and dead metal zone to the actual one was obtained.Using this geometry a die with similar surfaces to those of the dead metal zone is designed having converging and diverging surfaces to lead the material flow. The analysis was also carried out for this die and results were obtained showing a reduction in the extrusion pressure compared to the flat faced die. Effects of reduction of area, shape complexity, spread ratio and friction on the extrusion process were also investigated

  7. Orbital-angular-momentum photons for optical communication in non-Kolmogorov atmospheric turbulence

    Science.gov (United States)

    Wei, Mei-Song; Wang, Jicheng; Zhang, Yixin; Hu, Zheng-Da

    2018-06-01

    We investigate the effects of non-Kolmogorov atmospheric turbulence on the transmission of orbital-angular-momentum single photons for different turbulence aberrations in optical communication, via the channel capacity. For non-Kolmogorov model, the characteristics of atmosphere turbulence may be determined by different cases, including the increasing altitude, the mutative index-of-refraction structure constant and the power-law exponent of non-Kolmogorov spectrum. It is found that the influences of low-order aberrations, including Z-tilt, defocus, astigmatism, and coma aberrations, are different and the turbulence Z-tilt aberration plays a more important role in the decay of the signal.

  8. Study of elastic scattering between heavy ions. Reaction channel influence

    International Nuclear Information System (INIS)

    Doubre, Hubert.

    1978-01-01

    The role of absorption on the behavior of heavy ion angular distributions and excitaton functions has been investigated on light and medium mass systems. Comparison between 20 Ne+ 12 C and 16 O+ 16 O systems which lead to the same compound nucleus, shows that it originates from the direct channels strongly coupled to the entrance channel. Structures in the excitation functions occur for almost all the light systems and it is shown that the damping observed for heavier systems such as 40 Ca+ 40 Ca, essentially results on the predominance of Coulomb effects which hide the nuclear structure effects. Thus no valuable information on the details of S-matrix can be extracted for such an heavy system. A coherent description of the elastic scattering, based on a splitting of the scattering amplitude into two components, the modulus of each component varying smoothly as a function of energy and angle. The interference between these sub-amplitudes give rise to interference effects in angular distributions and excitation functions. The study of the main reaction channels of the 40 Ca+ 40 Ca system - i.e. deep inelastic reactions and fusion - also shows that the closed-shell nature of the interacting nuclei does not play any role in these processes due to the excitation processes in the first stage of the reactions which destroy the specific structure of the nuclei [fr

  9. 78 FR 34984 - Aluminum Extrusions From the People's Republic of China: Notice of Court Decision Not in Harmony...

    Science.gov (United States)

    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...

  10. Angular momentum from tidal torques

    International Nuclear Information System (INIS)

    Barnes, J.; Efstathiou, G.; Cambridge Univ., England)

    1987-01-01

    The origin of the angular momentum of bound objects in large N-body simulations is studied using three sets of models. One model with white-noise initial conditions is analyzed as well as two in which the initial conditions have more power on large scales, as predicted in models with cold dark matter. The growth and distribution of angular momentum in individual objects is studied and it is found that the specific angular momentum distribution of bound clumps increases in a near linear fashion with radius while the orientation of the angular momentum in the inner high-density regions is often poorly correlated with that of the outer parts. It is also found that the dimensionless spin parameter is insensitive to the initial perturbation spectrum and has a median value of about 0.05. 61 references

  11. Transverse and longitudinal angular momenta of light

    Energy Technology Data Exchange (ETDEWEB)

    Bliokh, Konstantin Y., E-mail: k.bliokh@gmail.com [Center for Emergent Matter Science, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Nonlinear Physics Centre, RSPhysE, The Australian National University, Canberra, ACT 0200 (Australia); Nori, Franco [Center for Emergent Matter Science, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Physics Department, University of Michigan, Ann Arbor, MI 48109-1040 (United States)

    2015-08-26

    We review basic physics and novel types of optical angular momentum. We start with a theoretical overview of momentum and angular momentum properties of generic optical fields, and discuss methods for their experimental measurements. In particular, we describe the well-known longitudinal (i.e., aligned with the mean momentum) spin and orbital angular momenta in polarized vortex beams. Then, we focus on the transverse (i.e., orthogonal to the mean momentum) spin and orbital angular momenta, which were recently actively discussed in theory and observed in experiments. First, the recently-discovered transverse spin  angular momenta appear in various structured fields: evanescent waves, interference fields, and focused beams. We show that there are several kinds of transverse spin angular momentum, which differ strongly in their origins and physical properties. We describe extraordinary features of the transverse optical spins and overview recent experiments. In particular, the helicity-independent transverse spin inherent in edge evanescent waves offers robust spin–direction coupling at optical interfaces (the quantum spin Hall effect of light). Second, we overview the transverse orbital angular momenta of light, which can be both extrinsic and intrinsic. These two types of the transverse orbital angular momentum are produced by spatial shifts of the optical beams (e.g., in the spin Hall effect of light) and their Lorentz boosts, respectively. Our review is underpinned by a unified theory of the angular momentum of light based on the canonical momentum and spin densities, which avoids complications associated with the separation of spin and orbital angular momenta in the Poynting picture. It allows us to construct a comprehensive classification of all known optical angular momenta based on their key parameters and main physical properties.

  12. Load beam unit replaceable inserts for dry coal extrusion pumps

    Science.gov (United States)

    Saunders, Timothy; Brady, John D.

    2012-11-13

    A track assembly for a particulate material extrusion pump according to an exemplary aspect of the present disclosure includes a link assembly with a roller bearing. An insert mounted to a load beam located such that the roller bearing contacts the insert.

  13. Track with overlapping links for dry coal extrusion pumps

    Science.gov (United States)

    Saunders, Timothy; Brady, John D

    2014-01-21

    A chain for a particulate material extrusion pump includes a plurality of links, each of the plurality of links having a link body and a link ledge, wherein each link ledge of the plurality of links at least partially overlaps the link body of an adjacent one of the plurality of links.

  14. Effects of fermentation and extrusion on the proximate composition ...

    African Journals Online (AJOL)

    The effect of extrusion and fermentation on the proximate composition and organoleptic properties of six combinations (100:0, 90:10, 80:20, 70:30, 60:40 and 50:50) of sorghum - soya blend were investigated. A total number of 19 microorganisms were isolated during the fermentation of sorghum-soya extrudates; these ...

  15. Density and superconducting properties of metal-sheathed YBa2Cu3Oy ceramic processed by hydrostatic extrusion

    International Nuclear Information System (INIS)

    Karpov, M.I.; Korzhov, V.P.; Artamoshin, A.V.; Prokopenko, V.M.

    1994-01-01

    Brittle materials can be deformed without cracking and rupturing using hydrostatic extrusion, which provides the greatest pore annihilation in powder-processed materials and allows large degrees of one-step deformation, which is favorable for texturing. Earlier, a casting slip prepared by mixing a starting powder of Y-based ceramic with an organic binder was conventionally extruded to produce a wire 150 μm in diameter. After special sintering, the critical-current density in the material attained a few hundred amperes per square centimeter at 77 K, and the wire could be rolled into a winding ≥0.3 m in diameter. Hydrostatic extrusion of an assembly composed of Y-based ceramic in a bimetallic Nb/Cu tube 30 mm in diameter was used to produce rods 6 mm in diameter; drawing of these rods yielded samples of wire 2 to 3 mm in diameter. It was shown that the extrusion pressure and strain substantially influence the yield of the rupture-free wire. No signs of rupturing, cracking, or necking were observed in wire extruded at pressures ≤700 MPa and degrees of deformation ≤50%. A pronounced instability of the hydrostatic extrusion, the appearance of defects, and even the rupture of the rods were caused by an increase in the pressure up to 2000 MPa and in the degree of one-step deformation up to 80%. In this work, the authors focus on the possibility of producing thin YBa 2 Cu 3 O y superconductors using only hydrostatic extrusion. They determined the parameters for the hydrostatic extrusion of the metal-sheathed YBa 2 Cu 3 O y ceramic to a diameter of 3 mm or to a rectangular cross section. Effects of the ceramic core, and of the reduction coefficient on superconducting-transition parameters and the critical-current density of the ceramic were examined

  16. Substrate dependent reaction channels of the Wolff–Kishner reduction reaction: A theoretical study

    Directory of Open Access Journals (Sweden)

    Shinichi Yamabe

    2014-01-01

    Full Text Available Wolff–Kishner reduction reactions were investigated by DFT calculations for the first time. B3LYP/6-311+G(d,p SCRF=(PCM, solvent = 1,2-ethanediol optimizations were carried out. To investigate the role of the base catalyst, the base-free reaction was examined by the use of acetone, hydrazine (H2N–NH2 and (H2O8. A ready reaction channel of acetone → acetone hydrazine (Me2C=N–NH2 was obtained. The channel involves two likely proton-transfer routes. However, it was found that the base-free reaction was unlikely at the N2 extrusion step from the isopropyl diimine intermediate (Me2C(H–N=N–H. Two base-catalyzed reactions were investigated by models of the ketone, H2N–NH2 and OH−(H2O7. Here, ketones are acetone and acetophenone. While routes of the ketone → hydrazone → diimine are similar, those from the diimines are different. From the isopropyl diimine, the N2 extrusion and the C–H bond formation takes place concomitantly. The concomitance leads to the propane product concertedly. From the (1-phenylethyl substituted diimine, a carbanion intermediate is formed. The para carbon of the phenyl ring of the anion is subject to the protonation, which leads to a 3-ethylidene-1,4-cyclohexadiene intermediate. Its [1,5]-hydrogen migration gives the ethylbenzene product. For both ketone substrates, the diimines undergoing E2 reactions were found to be key intermediates.

  17. Microemulsion extrusion technique: a new method to produce lipid nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jesus, Marcelo Bispo de, E-mail: dejesusmb@gmail.com; Radaic, Allan [University of Campinas-UNICAMP, Department of Biochemistry, Institute of Biology (Brazil); Zuhorn, Inge S. [University of Groningen, Department of Membrane Cell Biology, University Medical Center (Netherlands); Paula, Eneida de [University of Campinas-UNICAMP, Department of Biochemistry, Institute of Biology (Brazil)

    2013-10-15

    Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) have been intensively investigated for different applications, including their use as drug and gene delivery systems. Different techniques have been employed to produce lipid nanoparticles, of which high pressure homogenization is the standard technique that is adopted nowadays. Although this method has a high efficiency, does not require the use of organic solvents, and allows large-scale production, some limitations impede its application at laboratory scale: the equipment is expensive, there is a need of huge amounts of surfactants and co-surfactants during the preparation, and the operating conditions are energy intensive. Here, we present the microemulsion extrusion technique as an alternative method to prepare lipid nanoparticles. The parameters to produce lipid nanoparticles using microemulsion extrusion were established, and the lipid particles produced (SLN, NLC, and liposomes) were characterized with regard to size (from 130 to 190 nm), zeta potential, and drug (mitoxantrone) and gene (pDNA) delivery properties. In addition, the particles' in vitro co-delivery capacity (to carry mitoxantrone plus pDNA encoding the phosphatase and tensin homologue, PTEN) was tested in normal (BALB 3T3 fibroblast) and cancer (PC3 prostate and MCF-7 breast) cell lines. The results show that the microemulsion extrusion technique is fast, inexpensive, reproducible, free of organic solvents, and suitable for small volume preparations of lipid nanoparticles. Its application is particularly interesting when using rare and/or costly drugs or ingredients (e.g., cationic lipids for gene delivery or labeled lipids for nanoparticle tracking/diagnosis)

  18. Microemulsion extrusion technique: a new method to produce lipid nanoparticles

    International Nuclear Information System (INIS)

    Jesus, Marcelo Bispo de; Radaic, Allan; Zuhorn, Inge S.; Paula, Eneida de

    2013-01-01

    Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) have been intensively investigated for different applications, including their use as drug and gene delivery systems. Different techniques have been employed to produce lipid nanoparticles, of which high pressure homogenization is the standard technique that is adopted nowadays. Although this method has a high efficiency, does not require the use of organic solvents, and allows large-scale production, some limitations impede its application at laboratory scale: the equipment is expensive, there is a need of huge amounts of surfactants and co-surfactants during the preparation, and the operating conditions are energy intensive. Here, we present the microemulsion extrusion technique as an alternative method to prepare lipid nanoparticles. The parameters to produce lipid nanoparticles using microemulsion extrusion were established, and the lipid particles produced (SLN, NLC, and liposomes) were characterized with regard to size (from 130 to 190 nm), zeta potential, and drug (mitoxantrone) and gene (pDNA) delivery properties. In addition, the particles’ in vitro co-delivery capacity (to carry mitoxantrone plus pDNA encoding the phosphatase and tensin homologue, PTEN) was tested in normal (BALB 3T3 fibroblast) and cancer (PC3 prostate and MCF-7 breast) cell lines. The results show that the microemulsion extrusion technique is fast, inexpensive, reproducible, free of organic solvents, and suitable for small volume preparations of lipid nanoparticles. Its application is particularly interesting when using rare and/or costly drugs or ingredients (e.g., cationic lipids for gene delivery or labeled lipids for nanoparticle tracking/diagnosis)

  19. Study of the angular momentum distribution of compound nuclei obtained from fusion reactions close to the Coulomb barrier

    International Nuclear Information System (INIS)

    Romain, P.

    1990-03-01

    The effect of the mass asymmetry of the input channel on the compound nuclei spin distribution. The 16 O + 144 Nd and 80 Se + 80 Se reactions produce the same 160 Er compound nucleus in the 38 to 68 MeV energy range. In certain cases, the incident energies required to form the compound nucleus, at the same excitation energies, are very close to the Coulomb barrier. In the experimental device, the 'Chateau de Cristal' multidetector and additional sensors are used. The angular momentum distribution of the different evaporation products are measured by gamma spectrometry techniques. The fusion cross sections are measured by the time-of-flight technique. Theoretical predictions and experimental results concerning the distribution of the compound nucleus angular momentum are compared [fr

  20. Angular trap for macroparticles

    International Nuclear Information System (INIS)

    Aksyonov, D.S.

    2013-01-01

    Properties of angular macroparticle traps were investigated in this work. These properties are required to design vacuum arc plasma filters. The correlation between trap geometry parameters and its ability to absorb macroparticles were found. Calculations allow one to predict the behaviour of filtering abilities of separators which contain such traps in their design. Recommendations regarding the use of angular traps in filters of different builds are given.

  1. Spin-analysis of s-channel diphoton resonances at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M.C.; Ravindran, V. [Harish-Chandra Research Institute, Jhunsi, Allahabad (India). Regional Centre for Accelerator-Based Particle Physics; Mathews, P. [Saha Institute of Nuclear Physics, Kolkata (India); Pankov, A.A.; Tsytrinov, A.V. [Technical Univ. of Gomel (Belarus). The Abdus Salam ICTP Affiliated Centre; Paver, N. [Trieste Univ. (Italy); INFN-Trieste Section, Trieste (Italy)

    2011-08-15

    The high mass neutral quantum states envisaged by theories of physics beyond the standard model can at the hadron colliders reveal themselves through their decay into a pair of photons. Once such a peak in the diphoton invariant mass distribution is discovered, the determination of its spin through the distinctive photon angular distributions is needed in order to identify the associated nonstandard dynamics. We here discuss the discrimination of the spin-2 Randall- Sundrum graviton excitation against the hypothesis of a spin-0 exchange giving the same number of events under the peak, by means of the angular analysis applied to resonant diphoton events expected to be observed at the LHC. The spin-0 hypothesis is modelled by an effective interaction of a high mass gauge singlet scalar particle interacting with the standard model fields. The basic observable of our analysis is the symmetrically integrated angular asymmetry A{sub CE}, calculated for both graviton and scalar s-channel exchanges to next-to-leading order in QCD. (orig.)

  2. Channel Model of Molecular Communication via Diffusion in a Vessel-like Environment Considering a Partially Covering Receiver

    OpenAIRE

    Turan, Meriç; Kuran, Mehmet Sukru; Yilmaz, H. Birkan; Demirkol, Ilker; Tugcu, Tuna

    2018-01-01

    By considering potential health problems that a fully covering receiver may cause in vessel-like environments, the implementation of a partially covering receiver is needed. To this end, distribution of hitting location of messenger molecules (MM) is analyzed within the context of molecular communication via diffusion with the aim of channel modeling. The distribution of these MMs for a fully covering receiver is analyzed in two parts: angular and radial dimensions. For the angular distributi...

  3. Structure, texture, and mechanical properties of an MA2-1hp magnesium alloy after two-stage equal-channel angular pressing and intermediate annealing

    Science.gov (United States)

    Serebryany, V. N.; Perezhogin, V. Yu.; Raab, G. I.; Kopylov, V. I.; Tabachkova, N. Yu.; Sirotinkin, V. P.; Dobatkin, S. V.

    2015-01-01

    The effect of two-stage equal-channel angular pressing (ECAP) on the microstructure, the texture, and the mechanical properties of an MA2-1hp magnesium alloy is analyzed. ECAP leads to the formation of a submicrocrystalline structure with an average grain size of 640 nm, which includes Mg17Al12 phase particles with an average grain size of 240 nm and a volume fracture of 5.5%. A scattered tilted basal texture forms after ECAP, and its experimental pole figures are used for calculating orientation distribution functions and determining the volume fractions of the main orientations and the Schmid factors for different deformation systems. An increased activation of basal slip is found after both the first and the second stages of ECAP. As a result of two-stage ECAP, the strength properties of the alloy that correspond to the minimum acceptable values achieved by direct compression are obtained. Ductility is 44 and 18% after the first stage of ECAP plus subsequent annealing and after the second stage, respectively, which is almost four and two times higher than the initial value. The resulting strength mechanical properties of the alloy after the first and the second ECAP stages are analyzed using the Hall-Petch relation.

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

    Science.gov (United States)

    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®.

  5. Angular momentum in general relativity

    International Nuclear Information System (INIS)

    Cresswell, A.; Zimmerman, R.L.; Oregon Univ., Eugene

    1986-01-01

    It is argued that the correct expressions for the angular momentum flux carried by gravitational radiation should follow directly from the momentum currents. Following this approach, the authors compute the angular momentum associated with several different choices of energy-momentum prescriptions. (author)

  6. LATE TRIASSIC OBLIQUE EXTRUSION OF UHP/HP COMPLEXES IN THE ATBASHI ACCRETIONARY COMPLEX OF SOUTH TIANSHAN, KYRGYZSTAN

    Directory of Open Access Journals (Sweden)

    Wenjiao Xiao

    2017-01-01

    Full Text Available The exhumation and tectonic emplacement of eclogites and blueschists take place in forearc accretionary complexes by either forearc- or backarc-directed extrusion, but few examples have been well analysed in detail. Here we present an example of oblique wedge extrusion of UHP/HP rocks in the Atbashi accretionary complex of the Kyrgyz South Tianshan.

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

    Science.gov (United States)

    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.

  8. Hot-melt extrusion microencapsulation of quercetin for taste-masking.

    Science.gov (United States)

    Khor, Chia Miang; Ng, Wai Kiong; Kanaujia, Parijat; Chan, Kok Ping; Dong, Yuancai

    2017-02-01

    Besides its poor dissolution rate, the bitterness of quercetin also poses a challenge for further development. Using carnauba wax, shellac or zein as the shell-forming excipient, this work aimed to microencapsulate quercetin by hot-melt extrusion for taste-masking. In comparison with non-encapsulated quercetin, the microencapsulated powders exhibited significantly reduced dissolution in the simulated salivary pH 6.8 medium indicative of their potentially good taste-masking efficiency in the order of zein > carnauba wax > shellac. In vitro bitterness analysis by electronic tongue confirmed the good taste-masking efficiency of the microencapsulated powders. In vitro digestion results showed that carnauba wax and shellac-microencapsulated powders presented comparable dissolution rate with the pure quercetin in pH 1.0 (gastric) and 6.8 (intestine) medium; while zein-microencapsulated powders exhibited a remarkably slower dissolution rate. Crystallinity of quercetin was slightly reduced after microencapsulation while its chemical structure remained unchanged. Hot-melt extrusion microencapsulation could thus be an attractive technique to produce taste-masked bioactive powders.

  9. A Pearson VII distribution function for fast calculation of dechanneling and angular dispersion of beams

    International Nuclear Information System (INIS)

    Shao Lin; Peng Luohan

    2009-01-01

    Although multiple scattering theories have been well developed, numerical calculation is complicated and only tabulated values have been available, which has caused inconvenience in practical use. We have found that a Pearson VII distribution function can be used to fit Lugujjo and Mayer's probability curves in describing the dechanneling phenomenon in backscattering analysis, over a wide range of disorder levels. Differentiation of the obtained function gives another function to calculate angular dispersion of the beam in the frameworks by Sigmund and Winterbon. The present work provides an easy calculation of both dechanneling probability and angular dispersion for any arbitrary combination of beam and target having a reduced thickness ≥0.6, which can be implemented in modeling of channeling spectra. Furthermore, we used a Monte Carlo simulation program to calculate the deflection probability and compared them with previously tabulated data. A good agreement was reached.

  10. Strain transformation between tectonic extrusion and crustal thickening in the growth of the Tibetan Plateau

    Science.gov (United States)

    Liu, M.; Li, Y.; Sun, Y.; Shen, X.

    2017-12-01

    The Indo-Eurasian continental collision since 50 Ma has thickened the crust to raise the Himalayan-Tibetan Plateau and driven lateral extrusion of Asian lithospheric blocks to affect Cenozoic tectonics in central and east Asia. The relative roles of crustal thickening and tectonic extrusion, and the strain partitioning between them over time and space, remain controversial. We have analyzed the strain rates using GPS velocities, and correlated the results with vertical motion derived from precise leveling. We found that tectonic extrusion largely transforms to crustal thickening near the margins of the Tibetan Plateau. Near the NW margin of the Tibetan Plateau, the shear stain transforms to compressive strain, consistent with neotectonic studies that indicate crustal shortening and uplift. Around the SE margin, shear stain largely terminates in the southern Yunnan province of China. The present-day crustal motion in SE Tibetan Plateau can be well explained by gravitational spreading without invoking plate-edge push as envisioned in the tectonic extrusion model. Using data collected from local seismic arrays, we derived receiver functions to image the lithospheric structures across the Tibetan Plateau and the Alashan block to its north and the Ordos block to its east. Our results indicate that the mantle lithosphere of these bounding Asian blocks has not been reworked by Tibetan tectonics; instead they have acted as restrictive walls to the growing Tibetan Plateau. Our finite element modeling shows that crustal deformation along the margins of the Tibetan Plateau are consistent with the notion that the east- and southeastward extrusion of the Tibetan lithosphere is largely confined to the Tibetan Plateau because of the restrictive bounding blocks of the Asian lithosphere. Thus the tectonic impact of the Indo-Eurasian collision on the Cenozoic Asian tectonics may not be as extensive as previously thought.

  11. 2D CFD description of the kinematic effects of movable inlet and outlet die wall transport motion and punch shape geometry on the dynamics of viscous flow during ECAE through Segal 2θ-dies for a range of channel angles

    Directory of Open Access Journals (Sweden)

    Alexander V. Perig

    2017-11-01

    Full Text Available Minimization of the dead zone (DZA in the process of material forming is a materials science problem. Geometric and kinematic approaches to the minimization of the DZA during Equal Channel Angular Extrusion (ECAE have been proposed, developed, analyzed, and documented. The present article is focused on a 2D Computational Fluid Dynamics (CFD description of the kinematic effects of punch shape geometry and inlet (IDW and outlet (ODW die wall motion on the DZA during ECAE of Viscous Incompressible Continuum (VIC through a Segal 2θ-die for a range of channel angles 60° ≤ 2θ ≤ 135°. Due attention has been given to the independent alternating transport motions of the IDW and ODW. Punch shape geometry and the kinematic modes of IDW and ODW motions for DZA minimization have been determined with a numerical solution of the boundary value problem for the Navier-Stokes equations in curl transfer form for VIC. Experimental verification was accomplished with an introduction of initial circular gridlines-based physical simulation techniques. For the first time, experimental verification of CFD-derived results was made through an additional superposition of empirically-derived digital photos with deformed elliptical gridlines in the channel intersection deformation zones and correspondent 2D numerical plots with CFD-derived flow lines and full flow velocities. An empirical DZA localization was experimentally determined as the location of minimally-deformed near circular markers. The computational DZA localization was numerically determined as a flow-lines-free zone (the first hypothesis or as a zone with near-zero values of full flow velocities (the second hypothesis. The relative DZA was estimated as a ratio of the measured DZA with respect to the area of the deformation zone in the channel intersection region. A good agreement was obtained between DZA values obtained with the first hypothesis and experimental results.

  12. Oscillatory Shear Rheology in Examining the Drug-Polymer Interactions Relevant in Hot Melt Extrusion

    DEFF Research Database (Denmark)

    Aho, Johanna; Edinger, Magnus; Botker, Johan

    2016-01-01

    The flow properties of drug-polymer mixtures have a significant influence on their processability when using techniques such as hot melt extrusion (HME). Suitable extrusion temperature and screw speed to be used in laboratory scale HME were evaluated for mixtures containing 30% of paracetamol (PRC...... of the drug substances. Consecutively, the mixtures were extruded, and the maximum plasticizing weight fraction of each drug was determined by means of rheological measurements. IBU was found to have an efficient plasticizing functionality, decreasing the viscosity of the mixtures even above its apparent...

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

    Science.gov (United States)

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

    2015-12-01

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

  14. Search for entrance-channel dependence in the population of superdeformed bands in {sup 191}Hg

    Energy Technology Data Exchange (ETDEWEB)

    Soramel, F.; Khoo, T.L.; Janssens, R.V.F. [and others

    1995-08-01

    The population intensity of some SD bands in the mass 150 region were observed to depend on the mass symmetry of the entrance channel in the fusion reaction. The authors raised the possibility that the population of SD bands had a memory of the entrance channel. To check this interesting possibility, we made measurements of the population intensities of superdeformed (SD) bands in the {sup 160}Gd({sup 36}S,5n){sup 191}Hg and {sup 130}Te({sup 64}Ni,3n){sup 191}Hg reactions. To ensure that any observed effect was not due to a simple angular momentum difference in the entrance channels, we also measured the average entry points and spin distributions of normal and SD states in {sup 191}Hg in the two reactions. The entry points and spin distributions for {sup 191}Hg are the same and, indeed, so are the SD intensities in the two reactions. Hence, no entrance-channel effect is observed in the population of the SD band in {sup 191}Hg, in contrast with data for SD bands in the mass 150 regions. We suggest that the effect observed previously in the mass 150 region is due to an angular momentum effect. A letter reporting our results was submitted for publication.

  15. Desenvolvimento de misturas instantâneas de mandioca e caseína: efeito do teor de proteína e parâmetros de extrusão sobre a viscosidade Development of instant blends of cassava flour and casein: effect of protein contents and extrusion parameters on viscosity

    Directory of Open Access Journals (Sweden)

    Beatriz Helena Borges Lustosa

    2010-09-01

    Full Text Available O interesse da indústria de alimentos por produtos desenvolvidos a partir de farinhas acrescidas de proteína não se deve somente às suas características nutricionais, senão também às suas propriedades funcionais e reológicas, as quais definem as suas aplicações comerciais. Este trabalho teve por objetivo avaliar o efeito de parâmetros operacionais do processo de extrusão sobre as propriedades de pasta de misturas de farinha de mandioca e caseína. O processo de extrusão seguiu o delineamento 'central composto rotacional' para três fatores: teor de proteína (2,5 a 9,5%, umidade (14,5 a 19,5% e temperatura de extrusão (65 a 135 ºC. As misturas antes e após a extrusão foram analisadas no Rapid Visco Analyser (RVA quanto a: viscosidade inicial, pico de viscosidade, quebra de viscosidade, viscosidade final e tendência à retrogradação. Os resultados obtidos nas misturas antes da extrusão mostraram aumento dos valores de viscosidade com o aumento da concentração de proteína até o ponto central (6% e, nos teores mais elevados de proteína, ocorreu redução destes. Após a extrusão, observou-se que o teor de proteína foi a variável de maior efeito sobre as propriedades de pasta, seguida pela umidade das misturas.The interest of the food industry in products developed from flours added with protein is not due only to their nutritional characteristics, but also due to their functional and rheological properties, which define their commercial applications. This study aimed to evaluate the effect of operational parameters of the extrusion process on the paste properties of cassava flour and casein blends. The process of extrusion followed the central composed rotational design with three factors: protein content (2.5 to 9.5%, moisture (14.5 to 19.5%, and extrusion temperature (65 to 135 ºC. Before and after extrusion, the blends were analyzed on a Rapid Visco Analyser using the following parameters: initial viscosity, peak

  16. Resonant influence of a longitudinal hypersonic field on the radiation from channeled electrons

    International Nuclear Information System (INIS)

    Grigoryan, L.Sh.; Mkrtchyan, A.R.; Mkrtchyan, A.H.; Khachatryan, H.F.; Prade, H.; Wagner, W.; Piestrup, M.A.

    2001-01-01

    The wave function of a planar/axially channeled electron with energy 10 MeV≤E<<1 GeV under the influence of a longitudinal hypersonic wave excited in a single crystal is calculated. Conditions for the resonant influence of the hypersonic wave on the quantum state of the channeled electron are deduced. Expressions for the wave function that are applicable in the case of resonance are obtained. Angular and spectral distributions of the radiation intensity from the planar/axially channeled electron are also calculated. The possibility of significant amplification of channeling radiation by a hypersonic wave is substantiated. It is found that the hypersound can excite inverse radiative transitions through which the transversal energy of the channeled electron is increased. These transitions have a resonant nature and can lead to a considerable intensification of the electron channeling radiation. In the case of axial channeling, the resonance radiation is sustained also by direct radiative transitions of the electron

  17. Aluminum-graphite composite produced by mechanical milling and hot extrusion

    International Nuclear Information System (INIS)

    Flores-Zamora, M.I.; Estrada-Guel, I.; Gonzalez-Hernandez, J.; Miki-Yoshida, M.; Martinez-Sanchez, R.

    2007-01-01

    Aluminum-graphite composites were produced by mechanical milling followed by hot extrusion. Graphite content was varied between 0 and 1 wt.%. Al-graphite mixtures were initially mixed in a shaker mill without ball, followed by mechanical milling in a High-energy simoloyer mill for 2 h under argon atmosphere. Milled powders were subsequently pressed at ∼950 MPa for 2 min, and next sintered under vacuum for 3 h at 823 K. Finally, sintered products were held for 0.5 h at 823 K and hot extruded using indirect extrusion. Tension and compression tests were carried out to determine the yield stress and maximum stress of the materials. We found that the mechanical resistance increased as the graphite content increased. Microstructural characterization was done by transmission electron microscopy. Al-O-C nanofibers and graphite nanoparticles were observed in extruded samples by transmission electron microscopy. These nanoparticles and nanofibers seemed to be responsible of the reinforcement phenomenon

  18. Efeitos de parâmetros de extrusão nas propriedades físicas de produtos expandidos de inhame Effect of extrusion parameters in the physical properties of expanded yam snacks

    Directory of Open Access Journals (Sweden)

    Magali Leonel

    2006-06-01

    Full Text Available Neste trabalho, estudou-se o efeito de parâmetros de extrusão sobre o índice de expansão (IE, volume específico (VE, índice de absorção de água (IAA e índice de solubilidade em água (ISA de extrusados de inhame. O processamento foi executado em extrusor mono rosca. Para analisar o efeito combinado das variáveis independentes nas características tecnológicas dos extrusados de farinha de inhame, utilizou-se o delineamento 'central composto rotacional' para três fatores. O desenho experimental foi elaborado para verificar o efeito de três níveis de temperatura na última zona de extrusão (100, 115 e 130ºC, rotação da rosca (163, 204 e 245 rpm e umidade das farinhas (12, 15 e 18%. Os resultados obtidos mostraram que a umidade e a temperatura influenciaram os parâmetros de expansão (IE e VE. O índice de solubilidade em água (ISA foi dependente dos três parâmetros do processo. Temperatura elevada e alta rotação da rosca promoveram maiores valores de ISA. Nas condições estudadas, os parâmetros de extrusão não influenciaram o índice de absorção de água (IAA.Effect of extrusion parameters was studied on the expansion index, specific volume, water absorption index (WAI and water solubility index (WSI of expanded yam snacks. The central composite design was used to study the parameters effect. It was verified three levels of temperature in the barrel (100, 115 and 130ºC, three levels of screw speed (163, 204 and 245 rpm and three levels of flour moisture (12, 15 and 18%. The results showed that expansion properties (expansion index and specific volume depend on flour moisture and extrusion temperature. The WSI was dependant of three parameters. Higher levels of temperature and screw speed increase the water solubility index (WSI. The studied parameters did not influence the water absorption index (WAI.

  19. Apical extrusion of debris after hand, engine-driven reciprocating and continuous preparation = Extrusão apical de “debris” após o preparo manual e mecanizado oscilatório e contínuo

    Directory of Open Access Journals (Sweden)

    Luisi, Simone Bonato

    2010-01-01

    Conclusão: A técnica rotatória contínua com Pro-taper produziu maior quantidade de extrusão apical do que as técnicas coroa-ápice manual e mecanizada com sistema de rotação oscilatória. A direção da instrumentação, se cérvico-apical ou ápico-cervical, parece ser o fator mais determinante na extrusão de “debris” independente desta ser realizada manual ou mecanizada

  20. A new arthroscopic classification of degenerative medial meniscus root tear that correlates with meniscus extrusion on magnetic resonance imaging.

    Science.gov (United States)

    Bin, Seong-Il; Jeong, Tae-Wan; Kim, Su-Jin; Lee, Dae-Hee

    2016-03-01

    To determine a new classification system for medial meniscus root tears (MMRT) based on arthroscopic findings. 24 knees (55%) belonged to the nondisplaced or overlapped group, and 20 knees (45%) to the widely displaced group. Absolute meniscal extrusion was defined as distance between outer edge of the articular cartilage of tibial plateau and meniscal outer edge. Relative extrusion was defined as extruded meniscus width divided by entire meniscal width, multiplied by 100. The proportion of knees with major (>3 mm) extrusion were compared in two groups, as were the severity of chondral wear and osteoarthritic change. Absolute (4.6 mm vs. 3.7 mm, P=0.006) and relative (46% vs. 39%, P=0.042) extrusion of the medial meniscus were greater in widely displaced than in nondisplaced or overlapped group. Medial joint space width was significantly narrower in the widely displaced than in the nondisplaced or overlapped group (3.0 mm vs. 4.0 mm, P=0.007). The widely displaced group had a 4° greater varus deformity, and higher rates of major extrusion (>3 mm), grade III or IV chondral wear in the medial femoral condyle (60% vs. 29%, P=0.039) and medial compartment osteoarthritis (75% vs. 21%, P=0.001) than did the nondisplaced or overlapped group. Widely displaced MMRT had greater meniscal extrusion and more severe chondral wear and osteoarthritis than did nondisplaced or overlapped MMRT. In this novel classification system, the stage of MMRT severity was associated with tear site displacement. Case series (level IV). Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Effect of combined extrusion parameters on mechanical properties of basalt fiber-reinforced plastics based on polypropylene

    Science.gov (United States)

    Bashtannik, P. I.; Ovcharenko, V. G.; Boot, Yu. A.

    1997-11-01

    Basalt fibers are efficient reinforcing fillers for polypropylene because they increase both the mechanical and the tribotechnical properties of composites. Basalt fibers can compete with traditional fillers (glass and asbestos fibers) of polypropylene with respect to technological, economic, and toxic properties. The effect of technological parameters of producing polypropylene-based basalt fiber-reinforced plastics (BFRPs) by combined extrusion on their mechanical properties has been investigated. The extrusion temperature was found to be the main parameter determining the mechanical properties of the BFRPs. With temperature growth from 180 to 240°C, the residual length of the basalt fibers in the composite, as well as the adhesive strength of the polymer-fiber system, increased, while the composite defectiveness decreased. The tensile strength and elastic modulus increased from 35 to 42 MPa and 3.2 to 4.2 GPa, respectively. At the same time, the growth in composite solidity led to its higher brittleness. Thus, a higher temperature of extrusion allows us to produce materials which can be subjected to tensile and bending loads, while the materials produced at a lower temperature of extrusion are impact stable. The effect of the gap size between the extruder body and moving disks on the mechanical properties of the BFRPs is less significant than that of temperature. An increase of the gap size from 2 to 8 mm improves the impregnation quality of the fibers, but the extruder productivity diminishes. The possibility of controling the properties of reinforced polypropylene by varying the technological parameters of combined extrusion is shown. The polypropylene-based BFRPs produced by the proposed method surpass the properties of glass and asbestos fiber-reinforced plastics.

  2. Classical theory of the Kumakhov radiation in axial channeling. 1. Dipole approximation

    Energy Technology Data Exchange (ETDEWEB)

    Khokonov, M.K.; Komarov, F.F.; Telegin, V.I.

    1984-05-01

    The paper considers radiation of ultrarelativistic electrons in axial channeling initially predicted by Kumakhov. The consideration is based on the results of solution of the Fokker-Planck equation. The spectral-angular characteristics of the Kumakhov radiation in thick single crystals are calculated. It is shown that in heavy single crystals the energy losses on radiation can amount to a considerable portion of the initial beam energy. The possibility of a sharp increase of radiation due to a decrease of crystal temperature is discussed. It is shown that radiation intensity in axial channeling is weakly dependent on the initial angle of the electron entrance into the channel if this angle changes within the limits of a critical one.

  3. Extrusion cooking technology: Principal mechanism and effect on direct expanded snacks – An overview

    Directory of Open Access Journals (Sweden)

    Ajita Tiwari

    2017-04-01

    Full Text Available The snack industry is one of the fastest growing food sectors and is an important contributor within the global convenience food market. Nowadays snacks and convenience foods are also consumed regularly in India. Properly designed convenience foods can make an important contribution to nutrition in societies where social changes are altering traditional patterns of food preparation. Extrusion cooking as a popular means of preparing snack foods based on cereals and plant protein foodstuff has elicited considerable interest and attention over the past 30 years. Several studies on the extrusion of cereals and pulses, using various proportions, have been conducted because blends of cereals and pulses produce protein enriched products. Special importance is placed on the physicochemical and chemical modifications of protein, starch and dietary fibre. Extruded products can be categorized for a particular application based on their functional properties such as water absorption and water solubility index, expansion ratio, bulk density and viscosity of the dough.Therefore, the literature was reviewed for effect of extrusion processing on product parameters, and nutritional and anti-nutritional properties of extruded products.

  4. Efeito do tipo de elemento de rosca na degradação de polipropileno durante múltiplas extrusões Effect of screw element on the polypropylene degradation during multiple extrusions

    Directory of Open Access Journals (Sweden)

    Ana Clélia Babetto

    2000-06-01

    Full Text Available A configuração da rosca de uma extrusora de dupla rosca modular pode ser projetada com vários tipos de elementos de condução e mistura, produzindo diferentes níveis de degradação no polímero fundido. Neste trabalho determinou-se o nível de degradação do polipropileno durante múltiplas extrusões em várias configurações de rosca, através de cromatografia por exclusão de tamanho e espectroscopia de infravermelho. Houve decréscimo do peso molecular e estreitamento da sua distribuição em função do número de extrusões e do aumento da agressividade da rosca, assim como, aumento da concentração de carbonilas e insaturações na cadeia polimérica. O elemento de mistura EM90 causou o maior nível de degradação e a adição de elementos de condução esquerdos ECE reduziram o nível de degradação.The screw configuration of a double screw extruder can be designed to contain kneading and conveying elements inducing different levels of degradation in the polymer melt. In this work the level of degradation in polypropylene have been measured after multiple extrusions for various screw configurations using Size Exclusion Chromatography and Infra-Red Spectroscopy. The average molecular weight and the polydispersity are reduced and the carbonyl and unsaturation indices increase as the number of extrusions and the agressiveness of the screw increase. The kneading element with 90 degrees caused the greater level of degradation and the addition of left hand elements have reduced the level of degradation.

  5. Orbital Angular Momentum-based Space Division Multiplexing for High-capacity Underwater Optical Communications

    Science.gov (United States)

    Ren, Yongxiong; Li, Long; Wang, Zhe; Kamali, Seyedeh Mahsa; Arbabi, Ehsan; Arbabi, Amir; Zhao, Zhe; Xie, Guodong; Cao, Yinwen; Ahmed, Nisar; Yan, Yan; Liu, Cong; Willner, Asher J.; Ashrafi, Solyman; Tur, Moshe; Faraon, Andrei; Willner, Alan E.

    2016-09-01

    To increase system capacity of underwater optical communications, we employ the spatial domain to simultaneously transmit multiple orthogonal spatial beams, each carrying an independent data channel. In this paper, we show up to a 40-Gbit/s link by multiplexing and transmitting four green orbital angular momentum (OAM) beams through a single aperture. Moreover, we investigate the degrading effects of scattering/turbidity, water current, and thermal gradient-induced turbulence, and we find that thermal gradients cause the most distortions and turbidity causes the most loss. We show systems results using two different data generation techniques, one at 1064 nm for 10-Gbit/s/beam and one at 520 nm for 1-Gbit/s/beam; we use both techniques since present data-modulation technologies are faster for infrared (IR) than for green. For the 40-Gbit/s link, data is modulated in the IR, and OAM imprinting is performed in the green using a specially-designed metasurface phase mask. For the 4-Gbit/s link, a green laser diode is directly modulated. Finally, we show that inter-channel crosstalk induced by thermal gradients can be mitigated using multi-channel equalisation processing.

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

    Directory of Open Access Journals (Sweden)

    Leonardo Fábio Rivas

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

  7. Finite Element Analysis and Die Design of Non-specific Engineering Structure of Aluminum Alloy during Extrusion

    International Nuclear Information System (INIS)

    Chen, D.-C.; Lu, Y.-Y.

    2010-01-01

    Aluminum extension applies to industrial structure, light load, framework rolls and conveyer system platform. Many factors must be controlled in processing the non-specific engineering structure (hollow shape) of the aluminum alloy during extrusion, to obtain the required plastic strain and desired tolerance values. The major factors include the forming angle of the die and temperature of billet and various materials. This paper employs rigid-plastic finite element (FE) DEFORM 3D software to investigate the plastic deformation behavior of an aluminum alloy (A6061, A5052, A3003) workpiece during extrusion for the engineering structure of the aluminum alloy. This work analyzes effective strain, effective stress, damage and die radius load distribution of the billet under various conditions. The analytical results confirm the suitability of the current finite element software for the non-specific engineering structure of aluminum alloy extrusion.

  8. LHCb: Lifetime measurements and angular analysis of $B_s \\to J/\\Psi\\Phi$

    CERN Multimedia

    Sparkes, A

    2011-01-01

    Extracting the CP violating phase $\\Phi_s$ from the channel $B_s \\to J/\\Psi\\Phi$ is an important measurement for LHCb. This decay is a pseudoscalar to vector-vector transition and has three decay amplitudes which can be extracted by an angular analysis. Studies of untagged $B_s \\to J/\\Psi\\Phi$ decays using LHCb data recorded in 2010 allows us to measure the lifetime difference in $B_s$ mesons and verifies the method for extracting the weak CP violating phase $\\Phi_s$. Lifetime measurements for $B^+, B_d, B_s$ and $\\Lambda_b$ will also be presented.

  9. Optimization of extrusion process for production of nutritious pellets Otimização do processo de extrusão para a produção de pellets nutricional

    Directory of Open Access Journals (Sweden)

    Ernesto Aguilar-Palazuelos

    2012-03-01

    Full Text Available A blend of 50% Potato Starch (PS, 35% Quality Protein Maize (QPM, and 15% Soybean Meal (SM were used in the preparation of expanded pellets utilizing a laboratory extruder with a 1.5 × 20.0 × 100.0 mm die-nozzle. The independent variables analyzed were Barrel Temperature (BT (75-140 °C and Feed Moisture (FM (16-30%. The effect of extrusion variables was investigated in terms of Expansion Index (EI, apparent density (ApD, Penetration Force (PF and Specific Mechanical Energy (SME, viscosity profiles, DSC, crystallinity by X-ray diffraction, and Scanning Electronic Microscopy (SEM. The PF decreased from 30 to 4 kgf with the increase of both independent variables (BT and FM. SME was affected only by FM, and decreased with the increase in this variable. The optimal region showed that the maximum EI was found for BT in the range of 123-140 °C and 27-31% for FM, respectively. The extruded pellets obtained from the optimal processing region were probably not completely degraded, as shown in the structural characterization. Acceptable expanded pellets could be produced using a blend of PS, QPM, and SM by extrusion cooking.Neste trabalho foram elaborados pellets expandidos a partir da mistura de 50% de Amido de Batata (AB, 35% de Milho de Qualidade Protéica (MQP e 15% de Farelo de Soja (FS, utilizando extrusor de laboratório com matriz de 1,5 × 20,0 × 100,0 mm. As variáveis independentes analisadas foram: Temperatura de Extrusão (TE (75-140 °C e Umidade da Mistura (UM (16-30%. O efeito das variáveis de extrusão foram estudadas quanto ao Índice de Expansão (IE, a densidade aparente (DA, força de penetração (FP, Energia Mecânica Específica (EME, perfil de viscosidade, DSC, cristalinidade através de difração de raio X e Microscopia Eletrônica de Varredura (MEV. A PF diminuiu de 30 para 4 kgf com o aumento de ambas as variáveis independentes (TE e UM. EME foi afetada somente pela UM, diminuindo com o aumento desta variável. A regi

  10. Influence of the halo upon angular distributions for elastic scattering and breakup

    International Nuclear Information System (INIS)

    Capel, P.; Hussein, M.S.; Baye, D.

    2010-01-01

    The angular distributions for elastic scattering and breakup of halo nuclei are analysed using a near-side/far-side decomposition within the framework of the dynamical eikonal approximation. This analysis is performed for 11 Be impinging on Pb at 69 MeV/nucleon. These distributions exhibit very similar features. In particular they are both near-side dominated, as expected from Coulomb-dominated reactions. The general shape of these distributions is sensitive mostly to the projectile-target interactions, but is also affected by the extension of the halo. This suggests the elastic scattering not to be affected by a loss of flux towards the breakup channel.

  11. Orbital angular momentum in phase space

    International Nuclear Information System (INIS)

    Rigas, I.; Sanchez-Soto, L.L.; Klimov, A.B.; Rehacek, J.; Hradil, Z.

    2011-01-01

    Research highlights: → We propose a comprehensive Weyl-Wigner formalism for the canonical pair angle-angular momentum. → We present a simple and useful toolkit for the practitioner. → We derive simple evolution equations in terms of a star product in the semiclassical limit. - Abstract: A comprehensive theory of the Weyl-Wigner formalism for the canonical pair angle-angular momentum is presented. Special attention is paid to the problems linked to rotational periodicity and angular-momentum discreteness.

  12. Effect of conventional and extrusion pelleting on in situ ruminal degradability of starch, protein, and fibre in cattle

    DEFF Research Database (Denmark)

    Razzaghi, Ali; Larsen, Mogens; Lund, Peter

    2016-01-01

    +50% sugar beet pulp (SBP), or 50% maize+50% SBP. Meals were pelleted by either conventional pelleting, or by cooking extrusion using two distinct settings giving pellets with either high density (HD) or low density (LD). Ruminal degradation of starch, crude protein (CP) and NDF, and intestinal...... affected ruminal degradability of starch, protein, and NDF differently depending on both type of cereal and composition of the concentrate mixture.......>Pelleting>Meal). In contradiction, ESD for pure wheat and wheat mixtures was reduced, though differences were minor. Conventional pelleting reduced the effective protein degradability (EPD) for pure wheat, but extrusion did not further affect the EPD. In contrast, the most intense processing with extrusion LD increased EPD...

  13. Angular momentum projected wave-functions

    International Nuclear Information System (INIS)

    Bengtsson, R.; Haakansson, H.B.

    1978-01-01

    Angular momentum projection has become a vital link between intrinsic model-wavefunctions and the physical states one intends to describe. We discuss in general terms some aspects of angular momentum projection and present results from projection on e.g. cranking wavefunctions. Mass densities and spectroscopic factors are also presented for some cases. (author)

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

    Science.gov (United States)

    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).

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

    Science.gov (United States)

    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

  16. Multi-Channel Deconvolution for Forward-Looking Phase Array Radar Imaging

    Directory of Open Access Journals (Sweden)

    Jie Xia

    2017-07-01

    Full Text Available The cross-range resolution of forward-looking phase array radar (PAR is limited by the effective antenna beamwidth since the azimuth echo is the convolution of antenna pattern and targets’ backscattering coefficients. Therefore, deconvolution algorithms are proposed to improve the imaging resolution under the limited antenna beamwidth. However, as a typical inverse problem, deconvolution is essentially a highly ill-posed problem which is sensitive to noise and cannot ensure a reliable and robust estimation. In this paper, multi-channel deconvolution is proposed for improving the performance of deconvolution, which intends to considerably alleviate the ill-posed problem of single-channel deconvolution. To depict the performance improvement obtained by multi-channel more effectively, evaluation parameters are generalized to characterize the angular spectrum of antenna pattern or singular value distribution of observation matrix, which are conducted to compare different deconvolution systems. Here we present two multi-channel deconvolution algorithms which improve upon the traditional deconvolution algorithms via combining with multi-channel technique. Extensive simulations and experimental results based on real data are presented to verify the effectiveness of the proposed imaging methods.

  17. Rainbows in channeling of charged particles in crystals and nanotubes

    CERN Document Server

    Nešković, Nebojša; Ćosić, Marko

    2017-01-01

    This book discusses the effects, modeling, latest results, and nanotechnology applications of rainbows that appear during channeling of charged particles in crystals and nanotubes. The authors begin with a brief review of the optical and particle rainbow effects followed by a detailed description of crystal rainbows, which appear in ion channeling in crystals, and their modeling using catastrophe theory. The effects of spatial and angular focusing of channeled ions are described, with special attention given to the applications of the former effect to subatomic microscopy. The results of a thorough study of the recent high-resolution channeling experiments performed with protons of energies between 2.0 and 0.7 MeV and a 55 nm thick silicon crystal are also provided. This study opens up the potential for accurate analysis of very thin crystals. Also presented are recent results related to rainbows occurring in proton transmission through carbon nanotubes, and a detailed quantum consideration of the transmissio...

  18. Passive measurement-device-independent quantum key distribution with orbital angular momentum and pulse position modulation

    Science.gov (United States)

    Wang, Lian; Zhou, Yuan-yuan; Zhou, Xue-jun; Chen, Xiao

    2018-03-01

    Based on the orbital angular momentum and pulse position modulation, we present a novel passive measurement-device-independent quantum key distribution (MDI-QKD) scheme with the two-mode source. Combining with the tight bounds of the yield and error rate of single-photon pairs given in our paper, we conduct performance analysis on the scheme with heralded single-photon source. The numerical simulations show that the performance of our scheme is significantly superior to the traditional MDI-QKD in the error rate, key generation rate and secure transmission distance, since the application of orbital angular momentum and pulse position modulation can exclude the basis-dependent flaw and increase the information content for each single photon. Moreover, the performance is improved with the rise of the frame length. Therefore, our scheme, without intensity modulation, avoids the source side channels and enhances the key generation rate. It has greatly utility value in the MDI-QKD setups.

  19. Disc extrusions and bulges in nonspecific low back pain and sciatica: Exploratory randomised controlled trial comparing yoga therapy and normal medical treatment.

    Science.gov (United States)

    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.

  20. Virtual instrument automation of ion channeling setup for 1.7 MV tandetron accelerator

    International Nuclear Information System (INIS)

    Suresh, K.; Sundaravel, B.; Panigrahi, B.K.; Nair, K.G.M.; Viswanathan, B.

    2004-01-01

    A virtual instrument based automated ion channeling experimental setup has been developed and implemented in a 1.7 MV tandetron accelerator. Automation of the PC based setup is done using a windows based virtual instrument software allowing the setup to be easily ported between different computer operating systems. The virtual instrument software has been chosen to achieve quick and easy development of versatile, multi-purpose user friendly graphical interface for carrying out channeling experiments. The software has been modular designed to provide independent control of the stepper motors for fixing the sample at any user defined orientation, running and on-line display of azimuthal and tilt angular scans, auto storage of the angular scan data. Using this automated setup, the crystallographic axis of the sample can be aligned with the incident ion beam rapidly minimizing the beam damages to the sample. A standard single crystalline GaAs(100) has been characterized with this set up using 2 MeV He ++ ion beam. The crystalline quality (χ min ) and channeling half angle (ψ 1sol2 ) are measured to be 3.7% and 0.48 deg., respectively, which are close to the theoretical values. Salient features, working principles and design details of the automated setup are discussed in this paper