Relevant bibliographies by topics / Compression twin

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers

Academic literature on the topic 'Compression twin'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Compression twin.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Compression twin"

1

Adams, G. P., and W. Soedel. "Computation of Compression Loads in Twin Screw Compressors." Journal of Mechanical Design 117, no. 4 (December 1, 1995): 512–19. http://dx.doi.org/10.1115/1.2826712.

Full text
Abstract:
The compression mechanism in a twin screw compressor consists of two helical rotors. In this work, a method is presented for computing the forces and moments induced on each rotor due to gas compression. These are defined as the compression loads. The helical rotor surfaces are defined by the end profiles, wrap angle and rotor length. The 3D surface of each rotor is mapped to 2D integration regions. These regions correspond to the surfaces associated with individual compression chambers. The compression loads are computed by integrating the chamber pressure over the rotor surfaces. The integrals are evaluated at incremental values of the rotor angular position. The method is presented and implemented for a specific compressor configuration. The compression loads are resolved to forces at the bearing locations. These bearing forces are presented for operating pressures which represent an under-pressure condition. A frequency analysis demonstrates the rich frequency content of the bearing forces due to the sharpness of the compression loads as a function of the rotor angular position. In addition, it is demonstrated that the moment load about the axis of rotation induced on the female is approximately 12 percent of that induced on the male. Therefore, the female rotor motion approaches that of an idler gear.
APA, Harvard, Vancouver, ISO, and other styles
2

Lee, B. H., S. H. Park, Mohamad El Mehtedi, E. Evangelista, and Chong Soo Lee. "Influence of Initial Texture on Twin Formation and Plastic Deformation of Rolled AZ31 Mg Alloy." Advanced Materials Research 26-28 (October 2007): 149–52. http://dx.doi.org/10.4028/www.scientific.net/amr.26-28.149.

Full text
Abstract:
The influence of initial texture on the formation of primary twin system of AZ31 Magnesium rolled plate was investigated in this work. Uniaxial compression tests were carried out on samples cut along the rolling direction (RD) and normal direction (ND) of rolled AZ31 Mg plate at various temperatures (RT, 150, 200, 250, 300, 350, 400, 450°C) with the fixed strain rate (0.01s-1). The results showed that the primary twinning system of AZ31 Mg alloy (c-axis extension twin) occurred actively in the RD compression specimens, which promoted homogeneous deformation as compared to the ND compression specimens. The effect of temperature on the formation of deformation twins was also investigated, and slip/twin transition temperature was found to be 250°C.
APA, Harvard, Vancouver, ISO, and other styles
3

Hou, Long, Ying Niu, Yanchao Dai, Lansong Ba, Yves Fautrelle, Zongbin Li, Bo Yang, Claude Esling, and Xi Li. "Stress-induced detwinning and martensite transformation in an austenite Ni–Mn–Ga alloy with martensite cluster under uniaxial loading." IUCrJ 6, no. 3 (March 27, 2019): 366–72. http://dx.doi.org/10.1107/s2052252519003208.

Full text
Abstract:
Stress-induced martensitic detwinning and martensitic transformation during step-wise compression in an austenite Ni–Mn–Ga matrix with a martensite cluster under uniaxial loading have been investigated by electron backscatter diffraction, focusing on the crystallographic features of microstructure evolution. The results indicate that detwinning occurs on twins with a high Schmid factor for both intra-plate and inter-plate twins in the hierarchical structure, resulting in a nonmodulated (NM) martensite composed only of favourable variants with [001]NM orientation away from the compression axis. Moreover, the stress-induced martensitic transformation occurs at higher stress levels, undergoing a three-stage transformation from austenite to a twin variant pair and finally to a single variant with increasing compressive stress, and theoretical calculation shows that the corresponding crystallographic configuration is accommodated to the compression stress. The present research not only provides a comprehensive understanding of martensitic variant detwinning and martensitic transformation under compression stress, but also offers important guidelines for the mechanical training process of martensite.
APA, Harvard, Vancouver, ISO, and other styles
4

Ando, Shinji, Masayuki Tsushida, and Hiromoto Kitahara. "Deformation Behavior of Magnesium Single Crystal in c-Axis Compression and a-Axis Tension." Materials Science Forum 654-656 (June 2010): 699–702. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.699.

Full text
Abstract:
In general, deformation behavior of magnesium in compression is different from tensile. To investigate deformation behavior of magnesium single crystals by non-basal slips and twins, c-axis compression and a-axis tension tests were performed in the range of 77K-573K. The crystals were yielded by second order pyramidal slip, and the yield stress shows anomalous temperature dependence (increased with increasing temperature) between 203K and 293K. Yield stress of c-axis compression was bigger than that of a-axis tensile. In compression, fracture surface were (11 4) under 293K and were {30 4} above 373K, and fracture strain was smaller than the case of tension test. {10 1}-{10 2} double twin were activated at higher temperature and the crystal, therefore, fractured along the twin interface.
APA, Harvard, Vancouver, ISO, and other styles
5

Bao, Lei, Yudong Zhang, Christophe Schuman, Jean-Sébastien Lecomte, Marie-Jeanne Philippe, Xiang Zhao, and Claude Esling. "Multiple twinning in pure hexagonal close-packed titanium." Journal of Applied Crystallography 46, no. 5 (September 18, 2013): 1397–406. http://dx.doi.org/10.1107/s002188981302253x.

Full text
Abstract:
Commercial pure titanium (T40) was deformed in channel die compression by means of the split-sample technique in order to study multiple twinning. Particular attention was paid to the twin variant presentation and selection during multiple twinning. All possible misorientations, corresponding to the multiple twins arising from the combination of the {1 1 {\overline 2} 2} compression (C) twin, the {1 0 {\overline 1} 2} tension twin (T1) and the {1 1 {\overline 2} 1} tension twin (T2), were calculated with respect to the crystal basis of the matrix grain. All the multiple twin variants are partitioned into ten classes with the same crystallographically equivalent misorientation angle and axis. However, when the influence of twinning order is taken into account, the multiple twin variants are partitioned into 15 classes. Experimental results prove that the selection of twin variants (primary and secondary) is mainly governed by their macroscopic Schmid factor (SF). The normalized SF is more efficient at predicting variant selection. A twin formed in one grain can activate another twin in a neighbouring grain, provided that the angle between the two twinning planes does not exceed 20°.
APA, Harvard, Vancouver, ISO, and other styles
6

Ferreira, C. A. Infante, C. Zamfirescu, and D. Zaytsev. "Twin screw oil-free wet compressor for compression–absorption cycle." International Journal of Refrigeration 29, no. 4 (June 2006): 556–65. http://dx.doi.org/10.1016/j.ijrefrig.2005.10.006.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Li, Xiao, Ping Yang, and Li Meng. "Orientational Analysis on Static Recrystallization at Tension Twins in AZ31 Magnesium Alloy." Advanced Materials Research 299-300 (July 2011): 778–84. http://dx.doi.org/10.4028/www.scientific.net/amr.299-300.778.

Full text
Abstract:
The deformation depends on twinning in Mg alloy, and twins will be the dominant recrystallization nucleation site. Tension twinning proceeds much more easily than compression twinning since its volume fraction is much higher than that of compression twins, which may have a promotive effect on the recrystallization to a certain degree. Based on the previous research on the static recrystallization at compression twins, the evolution of microstructure and texture in AZ31 magnesium alloy during its static recystallization at tension twins was further investigated; and the orientational characteristics of new grains formed at tension twins in the early stage of static recrystallization were analyzed by EBSD technique. The results showed that the strong basal texture was retained and weakened with no new texture component being detected during annealing. New grains were observed to nucleate preferentially at the intersections of tension twin variants or the intersection between tension twins and compression twins. Their orientations are relatively random and are strongly scattered from those of original tension twins or compression twins. A comparison of the recrystallization at tension twins and compression twins was further made.
APA, Harvard, Vancouver, ISO, and other styles
8

Hu, Wei Hui, Tian Mo Liu, and Qing Liu. "Research on Hot Upsetting Deformation Behavior and Dynamic Recrystallization for AZ31." Key Engineering Materials 353-358 (September 2007): 722–25. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.722.

Full text
Abstract:
The AZ31 Mg alloy was upseted from 250°C to 500°C. In optical microscopy, as the temperature increases, the volume fraction of deformation twin will reduce to a minium and vanish. Simultaneously, some small dynamically recrystallized grains were observed at the boundaries of origin grains and twins. When temperatures rise from 350°C to 500°C , the volume fraction and size of DRX grains increases .By the compression test of the upsetting proof samples, the compressive strength reach a maxium, and reduce during further rising temperatures.
APA, Harvard, Vancouver, ISO, and other styles
9

Parlangeau, Camille, Alexandre Dimanov, Olivier Lacombe, Simon Hallais, and Jean-Marc Daniel. "Uniaxial compression of calcite single crystals at room temperature: insights into twinning activation and development." Solid Earth 10, no. 1 (February 7, 2019): 307–16. http://dx.doi.org/10.5194/se-10-307-2019.

Full text
Abstract:
Abstract. E-twinning is a common plastic deformation mechanism in calcite deformed at low temperature. Strain rate, temperature and confining pressure have negligible effects on twinning activation which is mainly dependent on differential stress. The critical resolved shear stress (CRSS) required for twinning activation is dependent on grain size and strain hardening. This CRSS value may obey the Hall–Petch relation, but due to sparse experimental data its actual evolution with grain size and strain still remains a matter of debate. In order to provide additional constraints on twinning activation and development, new mechanical tests were carried out at room temperature on unconfined single crystals of calcite, with different sizes and crystallographic orientations. Uniaxial deformation was performed at a controlled displacement rate, while the sample surface was monitored using optical microscopy and a high-resolution CCD (charge-coupled device) camera. The retrieved macroscopic stress–strain behavior of the crystals was correlated with the surface observations of the deformation process. Results show (1) the onset of crystal plasticity with the activation of the first isolated mechanical twins during the strain hardening stage, and (2) the densification and thickening of twin lamellae during the steady-state flow stress stage. Such thickening of twin lamellae at room temperature emphasizes that calcite twin morphology is not controlled solely by temperature. The different values for the CRSS obtained for the activation of isolated twins and for the onset of twin densification and thickening raises questions regarding the appropriate value to be considered when using calcite twin data for stress inversion purposes.
APA, Harvard, Vancouver, ISO, and other styles
10

Sun, Jing Li, and Jing Tao Wang. "Microstructures and Mechanical Properties of Pure Titanium by Dynamic Plastic Deformation." Materials Science Forum 667-669 (December 2010): 337–42. http://dx.doi.org/10.4028/www.scientific.net/msf.667-669.337.

Full text
Abstract:
Dynamic plastic deformation of commercially pure titanium in the temperature range of -100-18°C at the strain rates of 3.0×102-2.5×103, as well as at quasi-static compression were carried out by a Split Hopkinson Pressure Bar technique and conventional compression testing machine respectively. The formation of deformation twins plays a key role on the accommodation of a large amount of strain produced by plastic deformation. Grain orientation has a great influence on the formation of twins. Temperature has smaller effects than strain rate on the evolutions of the microstructures and mechanical properties. The area fraction of twins and their intersections increase with the increasing strain rate and the deformation strain, resulting in refined microstructures and higher hardness values. Strain rate also leads to the change of twin shape (type). While more lenticular twins are observed in samples after quasi-static deformation, there are lots of needle-like twins with straight and long boundaries in samples processed via dynamic plastic deformation. This may imply that different twin systems operate at different strain rate. For the needle-like twins in samples after dynamic plastic deformation, the twin area fraction approaches saturation beyond the true strain of about 0.13, which is significant turning point for twinning rate. This saturated trend is not observed in quasi-static deformation.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Compression twin"

1

Chan, Evan. "Wet-gas compression in twin-screw multiphase pumps." Thesis, [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1178.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Xu, Jian. "Modeling of wet gas compression in twin-screw multiphase pump." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2808.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Jong, Jae Ho. "Characteristics of jet impingement, drainage and compression in a forming roll of a twin-wire machine." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/NQ41558.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Piao, Kun. "An Elevated-Temperature Tension-Compression Test and Its Application to Mg AZ31B." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1316096630.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Scott, Jonathan Michael. "Failure Mechanisms and Texture Evolution of Wrought AZ31B Magnesium at Temperatures Ranging from 25 C to 125 C." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3135.

Full text
Abstract:
Failure mechanisms were studied in wrought AZ31B magnesium alloy under different strain paths and various temperatures. Optical micrographs were used to observe the formation of shear bands and regions of high twin density in samples strained under uniaxial, biaxial and plane strain conditions. Interrupted testing at 4% effective strain increments until failure was used to observe the evolution of the microstructure. Results showed that shear bands with a high percentage of twinned grains appeared early in the samples strained under biaxial or plane strain tension. These bands are similar to the failure region in uniaxial tension specimens. A forming limit diagram for AZ31B was developed from the strain data, showing that plane strain and biaxial tension had very similar limit strains, in contrast to materials like steel or aluminum alloys which typically have greater ductility in biaxial tension compared to plane strain tension. When the experiments are repeated at elevated forming temperatures of 75 C and 125 C there is no observable shear band formation. The forming limit diagrams for each temperature were created and showed a marked increase in biaxial tension formability, compared to plane strain tension. Optical microscopy showed no sign of any compression twins and very few tensile twins in samples strained in biaxial or plane strain tension, up to 12% effective strain. The lack of compression twins at these strain levels shows that the effect of temperature on critical resolved shear stress for < c+a > slip is greater than previously expected.
APA, Harvard, Vancouver, ISO, and other styles
6

Hattay, Jamel. "Wavelet-based lifting structures and blind source separation : applications to digital in-line holography." Rouen, 2016. http://www.theses.fr/2016ROUES016.

Full text
Abstract:
Ce projet de thèse expose des méthodes de traitement, dans le domaine des ondelettes, pour résoudre certains problèmes liés à la mise en oeuvre de l’holographie numérique dans l’axe. Ce developpement utilise des outils de la théorie de l’information et des divers moyens de traitement du signal tels que la séparation aveugle de sources (SAS). Cette technique est exploitée, ici, pour améliorer l’efficacité de l’holographie numérique, tels que la suppression de l’image jumelle, l’estimation de l’indice de réfraction, le codage et la transmission temps réel des hologrammes. Tout d’abord, nous donnons une brève introduction à la configuration dans l’axe de l’holographie numérique telle qu’elle est mise en oeuvre à l’UMR 6614 CORIA: l'explication de l’étape d’enregistrement ainsi que les différentes approches de restitution des hologrammes utilisés dans cette thèse. Ensuite, nous présentons un état de l’art des méthodes permettant de résoudre les deux principaux obstacles rencontrés dans la reconstruction des hologrammes numériques: l’étape de mise au point et la suppression de l’image jumelle. Ensuite, nous expliquons méticuleusement l’outil basé sur la transformée d’ondelettes, pour assurer une décomposition multi résolution de l’image, qui permet la séparation aveugle des images mélangées par un produit de convolution. Notre proposition consiste à utiliser la 2ème génération de la transformée en ondelettes d’une manière adaptative appelée aussi Schéma de lifting en quinconce Adaptif (SLQA). Cette décomposition est couplée à un algorithme de séparation appropriée pour former les trois étapes suivantes : les images d’entrées, mélangées par convolution, sont décomposées par SLQA pour former un arbre d’ondelettes. Ensuite, on applique l’algorithme de séparation sur le noeud le plus parcimonieux, généralement à la résolution la plus élevée, et enfin les images séparées sont reconstruites à l’aide de l’inverse de SLQA. Cet outil est appliqué pour résoudre plusieurs problèmes liés à des applications d’holographie numérique dans l’axe. Dans ce contexte, deux méthodes sont proposées. La première méthode, utilisant l’entropie globale, est développée pour rechercher de manière automatique le meilleur plan de mise au point des images holographiques. La deuxième méthode sert à supprimer l’image jumelle qui accompagne l’image restituée. Cette dernière se base sur la décomposition SLQA avec un algorithme de séparation statistique qui utilise la fameuse technique Analyse en Composantes Indépendantes (ACI). Vu que le formalisme d’un produit de convolution est retenu dans l’étape de formation de l’hologramme, l’outil SLQA et ACI assurent parfaitement la tâche de déconvolution. Les résultats expérimentaux confirment bien que nos deux méthodes proposées sont capables d’estimer le meilleur plan de mise au point et d’éliminer l’effet de l’image jumelle dans l’image restituée. Puis, nous proposons d’estimer l’épaisseur d’un anneau dans une image restituée d’un hologramme contenant la diffraction d’une bulle de vapeur stable dans une gouttelette d’un liquide. La dernière partie met en oeuvre le nouveau concept de Télé-Holographie. Il s’agit de mettre en place un échange de flux interactif entre la chambre d’enregistrement des hologrammes in-situ et un laboratoire distant au sein duquel s’effectue le traitement numérique de ces hologrammes. Pour atteindre cet objectif, nous proposons de réaliser une compression sans perte des hologrammes numériques par transformée en ondelettes. Pour la phase de la transmission progressive, selon la capacité du canal de transmission, nous proposons une manière efficace pour le codage de l’arbre des zéros des coefficients emboités obtenu par la transformée d’ondelette en quinconce (SLQA). Ce codeur nous permet une réduction considérable du débit binaire lors de la transmission des hologrammes. Les premiers tests effectués sur des hologrammes réels, enregistrés au sein du laboratoire CORIA, montrent une amélioration significative des taux de compression totale et de la taille de l’hologramme compressé
The present thesis is meant to develop specific processes, in the realm of wavelets domain, for certain digital holography applications. We mainly use the so-called blind source separation (BSS) techniques to solve numerous digital holography problems, namely, the twin image suppression, real time coding and transmission of holograms. Firstly, we give a brief introduction to in-line configuration of digital holography in flow measurements: the recording step explanation and the study of two reconstruction approaches that have been used during this thesis. Then, we emphasize the two well known obstacles of digital holograms reconstruction, namely, the determination of the best focus plane and the twin image removal. Secondly, we propose a meticulous scrutiny of the tool, based on the Blind Source Separation (BSS), enhanced by a multiscale decomposition algorithm, which enables the blind separation of convolutively mixed images. The suggested algorithm uses a wavelet-based transformer, called Adaptive Quincunx Lifting Scheme (AQLS), coupled with an appropriate unmixing algorithm. The resulting deconvolution process is made up of three steps. In the first step, the convolutively mixed images are decomposed by AQLS. Then, separation algorithm is applied to the most relevant component to unmix the transformed images. The unmixed images are, thereafter, reconstructed using the inverse of the AQLS transform. In a subsequent part, we adopt the blind source separation technique in the wavelet field domain to solve several problems related to digital holography. In this context, we present two main contributions for digital in-line hologram processing. The first contribution consists in an entropy-based method to retrieve the best focus plane, a crucial issue in digital hologram reconstruction. The second contribution consists in a new approach to remove a common unwanted artifact in holography called the twin image. The latter contribution is based on the blind source separation technique, and the resulting algorithm is made up of two steps: an Adaptive Quincunx Lifting Scheme (AQLS) based on the wavelet packet transform and a statistical unmixing algorithm based on Independent Component Analysis (ICA) tool. The role of the AQLS is to maximize the sparseness of the input holograms. Since the convolutive formalism is retained in digital in-line holography, BSS-based tool is extended and coupled with wavelet-based AQLS to fulfill the deconvolution task. Experimental results confirm that convolutive blind source separation is able to discard the unwanted twin image from digital in-line holograms. The last of this part consists in measuring the thickness of a ring. This ring is obtained from an improved reconstructed image of an hologram containing a vapor bubble created by thermal coupling between a laser pulse and nanoparticles in a droplet of a liquid. The last part introduces the Tele-Holography concept. Once the image of the object is perfectly reconstructed, the next objective is to code and transmit the reconstructed image for an interactive flow of exchange between a given laboratory, where the holograms are recorded, and a distant partner research. We propose the tele-holography process that involves the wavelet transform tool for lossless compression and transmission of digital holograms. The concept of tele-holography is motivated by the fact that the digital holograms are considered as a 2D image yielding the depth information of 3D objects. Besides, we propose a quincunx embedded zero-tree wavelet coder (QEZW) for scalable transmission. Owing to the transmission channel capacity, it reduces drastically the bit rate of the holography transmission flow. A flurry of experimental results carried out on real digital holograms show that the proposed lossless compression process yields a significant improvement in compression ratio and total compressed size. These experimentations reveal the capacities of the proposed coder in terms of real bitrate for progressive transmission
APA, Harvard, Vancouver, ISO, and other styles
7

Evon, Philippe. "Nouveau procédé de bioraffinage du tournesol plante entière par fractionnement thermo-mécano-chimique en extrudeur bi-vis : étude de l'extraction aqueuse des lipides et de la mise en forme du raffinat en agromatériaux par thermomoulage." Phd thesis, Toulouse, INPT, 2008. http://oatao.univ-toulouse.fr/7723/1/evon.pdf.

Full text
Abstract:
L'extraction aqueuse des lipides de la graine de tournesol est étudiée en contacteur agité. La diffusion à l'intérieur des particules est le facteur limitant de l'échange de matière. Les protéines sont impliquées dans l'entraînement et la stabilisation des lipides par l'eau. Le fractionnement de la plante entière est également étudié avec l'eau en extrusion bi-vis. Un extrait et un raffinat sont obtenus séparément et en une seule étape continue. Des rendements d'extraction en huile de 55 % peuvent être obtenus sous forme d'émulsions huile/eau. Leur stabilité est assurée par la présence à l'interface de tensioactifs : les phospholipides et les protéines voire les pectines. Les extraits se composent aussi d'une phase hydrophile. Prépondérante, elle contient des composés hydrosolubles (protéines, pectines…). Riches en fibres, les raffinats présentent une teneur significative en protéines au comportement thermoplastique. Ils peuvent être transformés en agromatériaux par thermomoulage.
APA, Harvard, Vancouver, ISO, and other styles
8

Martinelli, Marcelo. "Compressão de ruído quântico e efeitos transversos em osciladores paramétricos óticos." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-29052002-175731/.

Full text
Abstract:
Apresentamos neste trabalho o projeto e a construção de um Oscilador Paramétrico Ótico (OPO), demonstrando o caráter quântico da correlação de intensidade dos feixes sinal e complementar nele produzidos a partir de um feixe de bombeio de 532 nm. Estudamos ainda a compressão quântica de ruído no feixe de bombeio refletido por uma cavidade de OPO, obtendo 38 % de redução (abaixo do limite quântico) no ruído de quadratura de um feixe de 1064 nm produzido por um laser de Nd:YAG. Por fim, observamos a formação de estruturas nos feixes de saída para cavidades com modos transversos degenerados (confocal e concêntrica) e demonstramos pela primeira vez o caráter multimodo transverso das correlações quânticas em um OPO com cavidade confocal.
We present in this work the project and construction of an Optical Parametric Oscillator (OPO), showing the quantum behavior in the intensity correlation of signal and idler beams, generated from a 532 nm pump. We have also studied the quantum noise compression in the pump beam reflected from an OPO cavity, obtaining 38 % of noise reduction below the vacuum fluctuations in the quadrature of a 1064 nm beam coming from a Nd:YAG laser. Finally, we observed the pattern formation in the output beams for transverse degenerate cavities (confocal and concentric) and we show, for the first time to our knowledge, the transverse multimode behavior in the quantum correlation of a confocal OPO.
APA, Harvard, Vancouver, ISO, and other styles
9

Khosravani, Ali. "Application of High Resolution Electron Backscatter Diffraction(HR-EBSD) Techniques to Twinning Deformation Mechanism in AZ31 Magnesium Alloy." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3432.

Full text
Abstract:
The application of high resolution electron backscatter diffraction (HR-EBSD) techniques has been used in order to study the evolution of geometrically necessary dislocation (GND). The tested materials were taken from AZ31 magnesium sheet which had strong basal texture. Because of low symmetry of the magnesium crystal lattice, the von Mises criteria cannot be satisfied by the three independent, easily activated, basal slips. The strain along the c-axis of the crystal must be accommodated by either twinning and/or slip systems. HR-EBSD data was taken in order to investigate these phenomena. The HR-EBSD results were post processed in order to resolve total GND density onto the observed possible slip systems. The first chapter of the investigation focused on the correlation between resolved GNDs with tensile twin nucleation, and the subsequent propagation path in the microstructure. For this purpose, 2.5 % strain was applied in a uniaxial compression test along the transverse direction (TD). Several fine scan were done at the boundaries where twin formed. The results show that in order for a twin to nucleate spontaneously at the grain boundaries, two criteria should generally be met: high angle grain boundaries (35-45°) and pile ups of basal slip system in neighboring grain at the other side of the boundary. Furthermore, once nucleation has initiated, twin propagation can occur through low angle grain boundaries (15-25°); if a twin reaches a high angle boundary, it will generally terminate at the boundary at low strain levels. A twin may pass through high angle boundaries with further deformation. In the second chapter, deformation of the AZ31 magnesium alloy was study for different strain paths. For this purpose, compression and tension in-situ tests were done and the texture and GND evolutions were investigated. The results show that the load paths, compression and tension, evolve the microstructure in different ways. Massive twin fractions were formed in compression, and higher GND contents were observed in tension tests. It was observed that at higher strain levels GND contents are roughly independent of the initial texture but the activation of slip systems at low strain strongly depends on initial structure. If the samples were loaded along RD, GND density increased sharply at low strain. In contrast, for the samples loaded along TD, GND increased moderately. A small amount of repetition is apparent in the two parts of the thesis due to them being formatted for individual publication as journal papers.
APA, Harvard, Vancouver, ISO, and other styles
10

Chiu, Chao-ching, and 邱朝慶. "Vibration Analysis of Twin Screw Compressor." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/58333734464610442434.

Full text
Abstract:
碩士
國立中正大學
機械工程所
96
The thesis focuses on the vibration analysis of twin-screw compressors by using finite element software ANSYS. In the first part, the natural frequency and mode shapes of female and male rotors are investigated individually using ANSYS and the results are validated experimentally by modal testing. The deviations in natural frequency between ANSYS and experiment up to the first six modes all are within 7%. Moreover, results from ANSYS reveal that a torsional mode corresponding to 880 Hz while two rotors is meshing together is much lower than those of the individual modes of female and male rotors, respectively. It implies that this torsional mode plays an important role in the vibration of twin screw compressor. The second part of the thesis studies the vibration response for a twin screw compressor while the varying pressure is taken into consideration in the FEM model. The air pressure is obtained experimentally and then is transferred to the FEM model. Therefore the vibration response of the twin screw compressor is determined semi-empirically. A user-friendly interface is developed to conduct the vibration analysis of twin screw rotor with air pressure included automatically. By simply input the data of rotor profile and the contact line between two rotors, one may utilize this program integrated with ANSYS to determine the mode shapes, bearing forces, and stress distribution of a twin screw rotor.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "Compression twin"

1

Jong, Jae Ho. Characteristics of jet impingement, drainage and compression in a forming roll of a twin-wire machine. 1998.

Find full text
APA, Harvard, Vancouver, ISO, and other styles

Book chapters on the topic "Compression twin"

1

Oka, Akihiro, Satoshi Koyama, Teruo Izumi, and Yuh Shiohara. "Fabrication process of twin-free orthorhombic Nd123 single crystal under uni-axial compression." In Advances in Superconductivity XI, 729–32. Tokyo: Springer Japan, 1999. http://dx.doi.org/10.1007/978-4-431-66874-9_168.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Jiang, Jia, Andrew Godfrey, and Qing Liu. "EBSD Analysis and Theoretical Prediction of Twin Orientations during Compression in Mg-3Al-1Zn." In Key Engineering Materials, 627–30. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-456-1.627.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Yang, Ping, Li Meng, Q. G. Xie, and F. E. Cui. "A Preliminary Analysis on Compression Twins in Magnesium." In Materials Science Forum, 297–300. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-432-4.297.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Hequet, Anne-Gaëlle. "Twin Air Compressor for Energy Saving and Backup Capability." In Light Metals 2012, 613–15. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118359259.ch104.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Hequet, Anne-Gaëlle. "Twin air compressor for energy saving and back up capability." In Light Metals 2012, 613–15. Cham: Springer International Publishing, 2012. http://dx.doi.org/10.1007/978-3-319-48179-1_104.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Yang, P., L. Meng, X. Li, W. Mao, and L. Chen. "Microstructure and Micro-Texture Evolution of Compression Twins in Magnesium." In Ceramic Transactions Series, 637–43. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2008. http://dx.doi.org/10.1002/9780470444191.ch72.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Hamada, A. S., L. Pentti Karjalainen, Mahesh C. Somani, and R. M. Ramadan. "Deformation Mechanisms in High-Al Bearing High-Mn TWIP Steels in Hot Compression and in Tension at Low Temperatures." In Materials Science Forum, 217–22. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-434-0.217.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Samal, M. K. "Numerical Simulation of High Temperature Deformation Behavior of Nickel-Based Superalloys Using Crystal Plasticity Models and Finite Element Method." In Mathematical Concepts and Applications in Mechanical Engineering and Mechatronics, 414–46. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-1639-2.ch020.

Full text
Abstract:
Development of reliable computational models to predict the high temperature deformation behavior of nickel based super-alloys is in the forefront of materials research. These alloys find wide applications in manufacturing of turbine blades and discs of aircraft engines. The micro-structure of these alloys consists of the primary gamma-prime phase and the secondary and tertiary precipitates (of Ni3Al type) are dispersed as gamma-prime phases in the gamma-matrix. It is computationally expensive to incorporate the explicit finite element model of the micro-structure in a crystal plasticity based constitutive framework to simulate the response of the polycrystalline micro-structure. Existing models in literature do not account for these underlying micro-structural features which are important for simulation of polycrystalline response. The aim of this chapter is to present a physically-motivated multi-scale approach for simulation of high temperature response of Nickel-based super-alloys. At the lower length scale, a dislocation density based crystal plasticity model is developed which simulates the response of various types of micro-structures. The micro-structures are designed with various shapes and volume fractions of gamma-prime precipitates. A new model for simulation of the mechanism of anti-phase boundary shearing of the gamma-prime precipitates, by the matrix dislocations, is presented in this chapter. The lower scale model is homogenized as a function of various micro-structural parameters and the homogenized model is used in the next scale of multi-scale simulation. In addition, a new criterion for initiation of micro-twin and a constitutive model for twin strain accumulation are developed. This new micro-twin model along with the homogenized crystal plasticity model has been used to simulate the creep response of a single crystal nickel-based super-alloy and the results have been compared with those of experiment from literature. It was observed that the new model has been able to model the tension-compression asymmetry as observed in single crystal experiments.
APA, Harvard, Vancouver, ISO, and other styles
9

Samal, M. K. "Numerical Simulation of High Temperature Deformation Behavior of Nickel-Based Superalloys Using Crystal Plasticity Models and Finite Element Method." In Materials Science and Engineering, 341–73. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-1798-6.ch013.

Full text
Abstract:
Development of reliable computational models to predict the high temperature deformation behavior of nickel based super-alloys is in the forefront of materials research. These alloys find wide applications in manufacturing of turbine blades and discs of aircraft engines. The micro-structure of these alloys consists of the primary gamma-prime phase and the secondary and tertiary precipitates (of Ni3Al type) are dispersed as gamma-prime phases in the gamma-matrix. It is computationally expensive to incorporate the explicit finite element model of the micro-structure in a crystal plasticity based constitutive framework to simulate the response of the polycrystalline micro-structure. Existing models in literature do not account for these underlying micro-structural features which are important for simulation of polycrystalline response. The aim of this chapter is to present a physically-motivated multi-scale approach for simulation of high temperature response of Nickel-based super-alloys. At the lower length scale, a dislocation density based crystal plasticity model is developed which simulates the response of various types of micro-structures. The micro-structures are designed with various shapes and volume fractions of gamma-prime precipitates. A new model for simulation of the mechanism of anti-phase boundary shearing of the gamma-prime precipitates, by the matrix dislocations, is presented in this chapter. The lower scale model is homogenized as a function of various micro-structural parameters and the homogenized model is used in the next scale of multi-scale simulation. In addition, a new criterion for initiation of micro-twin and a constitutive model for twin strain accumulation are developed. This new micro-twin model along with the homogenized crystal plasticity model has been used to simulate the creep response of a single crystal nickel-based super-alloy and the results have been compared with those of experiment from literature. It was observed that the new model has been able to model the tension-compression asymmetry as observed in single crystal experiments.
APA, Harvard, Vancouver, ISO, and other styles
10

Chakraborty, Chinmay. "Performance Analysis of Compression Techniques for Chronic Wound Image Transmission Under Smartphone-Enabled Tele-Wound Network." In Research Anthology on Telemedicine Efficacy, Adoption, and Impact on Healthcare Delivery, 345–64. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-8052-3.ch018.

Full text
Abstract:
The healing status of chronic wounds is important for monitoring the condition of the wounds. This article designs and discusses the implementation of smartphone-enabled compression technique under a tele-wound network (TWN) system. Nowadays, there is a huge demand for memory and bandwidth savings for clinical data processing. Wound images are captured using a smartphone through a metadata application page. Then, they are compressed and sent to the telemedical hub with a set partitioning in hierarchical tree (SPIHT) compression algorithm. The transmitted image can then be reduced, followed by an improvement in the segmentation accuracy and sensitivity. Better wound healing treatment depends on segmentation and classification accuracy. The proposed framework is evaluated in terms of rates (bits per pixel), compression ratio, peak signal to noise ratio, transmission time, mean square error and diagnostic quality under telemedicine framework. A SPIHT compression technique assisted YDbDr-Fuzzy c-means clustering considerably reduces the execution time (105s), is simple to implement, saves memory (18 KB), improves segmentation accuracy (98.39%), and yields better results than the same without using SPIHT. The results favor the possibility of developing a practical smartphone-enabled telemedicine system and show the potential for being implemented in the field of clinical evaluation and the management of chronic wounds in the future.
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Compression twin"

1

Barker, P. A. "Stress Corrosion Cracking in Twin Ferrule Compression Fittings in SS31600." In SPE International Oilfield Corrosion Conference and Exhibition. Society of Petroleum Engineers, 2018. http://dx.doi.org/10.2118/190887-ms.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Yata, Susumu, Masaki Oono, Kazuhiro Morita, Toru Sumitomo, and Jun-ichi Aoe. "Double-array compression by pruning twin leaves and unifying common suffixes." In Informatics (ICOCI). IEEE, 2006. http://dx.doi.org/10.1109/icoci.2006.5276476.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Sajjad, Saqib, Eisa Al Jenaibi, and Praveen Hakki. "Integrated Thermodynamic Digital Twin for Energy Performance Monitoring of Large Compression Units." In Abu Dhabi International Petroleum Exhibition & Conference. Society of Petroleum Engineers, 2020. http://dx.doi.org/10.2118/203358-ms.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Browne, Florian, George Chiu, and Neera Jain. "Dynamic Modeling of Twin-Roll Steel Strip Casting." In ASME 2016 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/dscc2016-9698.

Full text
Abstract:
We consider the problem of dynamic coupling between the rapid thermal solidification and mechanical compression of steel in twin-roll steel strip casting. In traditional steel casting, molten steel is first solidified into thick slabs and then compressed via a series of rollers to create thin sheets of steel. In twin-roll casting, these two processes are combined, thereby making control of the overall system significantly more challenging. Therefore, a simple and accurate model that characterizes these coupled dynamics is needed for model-based control of the system. We model the solidification process with explicit consideration for the mushy (semi-solid) region of steel by using a lumped parameter moving boundary approach. The moving boundaries are also used to estimate the size and composition of the region of steel that must be compressed to maintain a uniform strip thickness. A novelty of the proposed model is the use of a stiffening spring to characterize the stiffness of the resultant strip as a function of the relative amount of mushy and solid steel inside the compression region. In turn this model is used to determine the force required to carry out the compression. Simulation results demonstrate key features of the overall model.
APA, Harvard, Vancouver, ISO, and other styles
5

Raju, Thokala Soloman, Angelina Prince, Prasanta K. Panigrahi, and C. Nagaraja Kumar. "Compression and Propagation of Spatially Modulated Optical Similaritons in Asymmetric Twin-core Fibers." In International Conference on Fibre Optics and Photonics. Washington, D.C.: OSA, 2014. http://dx.doi.org/10.1364/photonics.2014.m4a.31.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Sammak, Majed, Magnus Genrup, Egill Thorbergsson, and Tomas Grönstedt. "Conceptual Mean-Line Design of Single and Twin-Shaft Oxy-Fuel Gas Turbine in a Semi-Closed Oxy-Fuel Combustion Combined Cycle." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-69470.

Full text
Abstract:
The aim of this study was to compare single- and twin-shaft oxy-fuel gas turbines in a semi-closed oxy-fuel combustion combined cycle (SCOC-CC). This paper discussed the turbomachinery preliminary mean-line design of oxy-fuel compressor and turbine. The conceptual turbine design was performed using the axial through-flow code LUAX-T, developed at Lund University. A tool for conceptual design of axial compressors developed at Chalmers University was used for the design of the compressor. The modeled SCOC-CC gave a net electrical efficiency of 46% and a net power of 106 MW. The production of 95% pure oxygen and the compression of CO2 reduced the gross efficiency of the SCOC-CC by 10 and 2 percentage points, respectively. The designed oxy-fuel gas turbine had a power of 86 MW. The rotational speed of the single-shaft gas turbine was set to 5200 rpm. The designed turbine had four stages, while the compressor had 18 stages. The turbine exit Mach number was calculated to be 0.6 and the calculated value of AN2 was 40·106 rpm2m2. The total calculated cooling mass flow was 25% of the compressor mass flow, or 47 kg/s. The relative tip Mach number of the compressor at the first rotor stage was 1.15. The rotational speed of the twin-shaft gas generator was set to 7200 rpm, while that of the power turbine was set to 4500 rpm. Twin-shaft turbine designed with five turbine stages to maintain the exit Mach number around 0.5. The twin-shaft turbine required a lower exit Mach number to maintain reasonable diffuser performance. The compressor turbine was designed with two stages while the power turbine had three stages. The study showed that a four-stage twin-shaft turbine produced a high exit Mach number. The calculated value of AN2 was 38·106 rpm2m2. The total calculated cooling mass flow was 23% of the compressor mass flow, or 44 kg/s. The compressor was designed with 14 stages. The preliminary design parameters of the turbine and compressor were within established industrial ranges. From the results of this study it was concluded that both single- and twin-shaft oxy-fuel gas turbines have advantages. The choice of a twin-shaft gas turbine can be motivated by the smaller compressor size and the advantage of greater flexibility in operation, mainly in off-design mode. However, the advantages of a twin-shaft design must be weighed against the inherent simplicity and low cost of the simple single-shaft design.
APA, Harvard, Vancouver, ISO, and other styles
7

Nakashima, Celso Yukio, Silvio de Oliveira Ju´nior, and Elisio F. Caetano. "Thermodynamic Model of a Twin-Screw Multiphase Pump." In ASME 2002 Engineering Technology Conference on Energy. ASMEDC, 2002. http://dx.doi.org/10.1115/etce2002/prod-29164.

Full text
Abstract:
The twin-screw multiphase pump has been studied as an alternative system to substitute the conventional one (fluid separation, liquid pumping and gas compression) in petroleum boosting. By “pumping” simultaneously gas and liquid, the multiphase pump could reduce production costs in deepwater activities. This paper presents a thermodynamic model of a twin-screw multiphase pump to determine performance parameters such as: absorbed power, discharge conditions and efficiency. To overcome problems with the complex flow field inside of this novel equipment, the multiphase flow was divided into a sequence of simpler processes. Such approach helps determine energy and mass balances and enables the use of a process simulator (Hysys.Process v2.1) to construct the model. The model prediction when compared to the literature show that the assumption of a smooth turbulent flow, considering the pressure loss in the entrance and discharge of the gap, fits better the phenomena than the turbulent flow when calculating the flow through the gaps. In addition, the comparison for absorbed power indicates that the assumption of gaps filled only with liquid is not valid under all operation conditions.
APA, Harvard, Vancouver, ISO, and other styles
8

Nakashima, Celso Y., Silvio Oliveira, and Elisio F. Caetano. "Thermo-Hydraulic Model of a Twin-Screw Multiphase Pump." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-60139.

Full text
Abstract:
The twin-screw multiphase pump has been studied as an alternative equipment to substitute the conventional system (fluid separation, liquid pumping and gas compression) in petroleum boosting. By “pumping” gas and liquid together, the multiphase pump could reduce production costs, particularly in deepwater activity. This paper presents a thermo-hydraulic model of a twin-screw multiphase pump developed to determine important parameters such as: volumetric efficiency, absorbed power, discharge conditions, heat transfer and pressure and temperature profiles. The continuous movement from suction to the discharge of pump chambers is divided in small discretive steps. This division allows the calculation of energy and mass balances for each screw chamber. At each step, it is possible to calculate mass and energy that enters and leaves one chamber. With this balance, pressure and temperature for the next step can be calculated. Differently from previous model, it considers not only water-air but also hydrocarbon mixtures (including petroleum heavy fractions) as working fluids. Besides, inclusion of screw rotation influence over peripheral backflow is not neglected as in previous models.
APA, Harvard, Vancouver, ISO, and other styles
9

Leinhos, Dirk C., Stephen G. Scheidler, Leonhard Fottner, Frank Grauer, Jakob Hermann, Manuel Mettenleiter, and Armin Orthmann. "Experiments in Active Stall Control of a Twin-Spool Turbofan Engine." In ASME Turbo Expo 2002: Power for Land, Sea, and Air. ASMEDC, 2002. http://dx.doi.org/10.1115/gt2002-30002.

Full text
Abstract:
The aerodynamic stability of aero engine compressors must be assured by active control systems in all operating conditions when the design surge margin is reduced in order to improve efficiency. While this has been investigated only on compressor rigs and single-spool engines in the past, this study focuses on the active control of the LARZAC 04 twin-spool turbofan. The objective is to demonstrate potential benefits, problems and solutions and also to provide a data base for numerical modeling and simulation of the capabilities of active control. Three different control strategies have been employed each of which refers to a specific operating condition and instability inception of the engine: The attenuation of disturbances travelling at rotor speed by modulated air injection into the LPC in the high speed range, the recovery of fully developed LPC stall at low speeds with a minimized amount of air and finally a constant air recirculation (HPC exit to LPC inlet) for stabilizing the compression system at different speeds based on the monitoring of a stability parameter. The injector is mounted upstream of the LPC and has ten circumferentially distributed nozzles for air injection into the tip region of the first rotor. The injected air which is either taken from an external source or from bleed air ports at the HPC exit is controlled by high-bandwidth direct-drive-valves. Disturbances travelling at rotor speed can be detected and attenuated with modulated air injection leading to a delay of stall onset. Fully developed rotating stall in the LPC was eliminated by asymmetric injection based on modal control strategies with less air than needed with constant air injection. By using online-stability-monitoring it is possible to initiate constant air recirculation when approaching the surge line, though the current design of the injector does not allow for large extension of the operating range for all spool speeds.
APA, Harvard, Vancouver, ISO, and other styles
10

Anderson, Kevin R., and Trevor Steele. "Analysis of a FAME/MLL Screw Multi-Stage Compressor for High Temperature, High Pressure Vapor Compression Refrigeration Cycle." In ASME 2020 Fluids Engineering Division Summer Meeting collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/fedsm2020-20002.

Full text
Abstract:
Abstract This paper presents the analysis and design of a compressor for application to a Fatty Acid Methyl Ester (FAME) Methyl Linoleate (MLL) bio-refrigerant cascade working cycle. This working fluid is being used in the topping cycle of an active electronics payload cooling system design to operate at elevated temperatures and pressures such as those witnessed by a Venus lander. The twin-screw, three-stage compressor operates at escalated temperatures of approximately 520 °C (960 °F). The total compressor power of 143.4 W is shared as 43.5 W, 47.7 W, and 53.3 W over stages 1, 2, and 3, respectively. The screw compressor is baselined with a D = 1 inch diameter rotor and an L/D (stroke/bore) ratio of L/D = 2 per stage. The compression ratio corresponds to a volume ratio of 6.5. The swept volume for a 4+6 rotor configuration is estimated to be 1.13 CFM at 2000 RPM with an asymmetric profile and no leakage. The volumetric efficiency of the compressor is estimated to be on the order of 80% due to the higher molecular weight of the FAME/MLL working fluid. The SCORG turbomachinery software is used to verify the thermodynamics analysis and affords a volumetric displacement of 0.025 L/rev at 2000 RPM and 80% adiabatic efficiency.
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'Compression twin' for particular source types:
Journal articles Dissertations / Theses
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography