Готові списки джерел за темами / Density distortion

Добірка наукової літератури з теми "Density distortion"

Автор: Grafiati
Опубліковано: 14 березня 2023

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Статті в журналах з теми "Density distortion"

1

Wang, Q. C., Xiao Dong Hu, W. Li, and Ju Long Yuan. "Numerical Simulation of Machining Distortion of Residually Stressed Aircraft Aluminum Components." Key Engineering Materials 315-316 (July 2006): 235–38. http://dx.doi.org/10.4028/www.scientific.net/kem.315-316.235.

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The presence of residual stress in aircraft aluminum components can give rise to distortion after machining. Excessive distortion may result in the rejection of a part or the need for costly and time-consuming rework prior to placement in service. The purpose of this research was to develop a methodology for the prediction of machining-induced distortions of residually stressed aircraft aluminum components. Numerical simulation results show that the magnitude of machining distortion is strongly related to the square root of Stain Energy Density W or Stress Range σ . The experimental results demonstrate good agreement with the predicted machining distortions of 7075T73 bulkheads. It included that the original residual stress in the blocks of aircraft aluminum component is one of key factors to cause machining distortion.
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2

Harvey, Pierre D., and Christian Reber. "Article." Canadian Journal of Chemistry 77, no. 1 (January 1, 1999): 16–23. http://dx.doi.org/10.1139/v98-212.

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Density functional theory is used to characterize the lowest energy excited spin triplet orbital configurations of square-planar halide complexes of palladium(II). Calculations for the eg –> b1g orbital excitation (D4h labels) predict a non-totally symmetric distortion along the b1g normal coordinate, leading to unequal bond lengths for perpendicular metal-ligand bonds (D2h symmetry). Calculated bond length changes are 0.15 Å (0.11 Å) and 0.05 Å (0.00 Å) for PdCl42- (PdBr42-). These values compare favorably to the emitting-state distortions of 0.12 Å and 0.09 Å for K2PdCl4 (0.12 Å, and 0.07 Å for K2PdBr4) determined from resolved single-crystal luminescence spectra. The calculations indicate that the non-totally symmetric distortion is an intrinsic molecular property of these complexes.Key words: palladium(II) complexes, excited state distortions, density functional theory.
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3

Wang, Kan, and Meng Wang. "Aero-optics of subsonic turbulent boundary layers." Journal of Fluid Mechanics 696 (February 24, 2012): 122–51. http://dx.doi.org/10.1017/jfm.2012.11.

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AbstractCompressible large-eddy simulations are carried out to study the aero-optical distortions caused by Mach 0.5 flat-plate turbulent boundary layers at Reynolds numbers of ${\mathit{Re}}_{\theta } = 875$, 1770 and 3550, based on momentum thickness. The fluctuations of refractive index are calculated from the density field, and wavefront distortions of an optical beam traversing the boundary layer are computed based on geometric optics. The effects of aperture size, small-scale turbulence, different flow regions and beam elevation angle are examined and the underlying flow physics is analysed. It is found that the level of optical distortion decreases with increasing Reynolds number within the Reynolds-number range considered. The contributions from the viscous sublayer and buffer layer are small, while the wake region plays a dominant role, followed by the logarithmic layer. By low-pass filtering the fluctuating density field, it is shown that small-scale turbulence is optically inactive. Consistent with previous experimental findings, the distortion magnitude is dependent on the propagation direction due to anisotropy of the boundary-layer vortical structures. Density correlations and length scales are analysed to understand the elevation-angle dependence and its relation to turbulence structures. The applicability of Sutton’s linking equation to boundary-layer flows is examined, and excellent agreement between linking equation predictions and directly integrated distortions is obtained when the density length scale is appropriately defined.
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4

Luty, Tadeusz, and John C. Raich. "Molecular to atomic transformation in solid iodine under high pressure." Canadian Journal of Chemistry 66, no. 4 (April 1, 1988): 812–18. http://dx.doi.org/10.1139/v88-141.

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Structural transformations in solid iodine under high pressure are analyzed from the point of view of symmetries of possible charge density distortions coupled to phonons. The transition from the high pressure atomic phase to the low pressure molecular phase is interpreted in terms of phonon softening and formation of molecular bonds and is seen as a condensation of a charge density distortion wave coupled to a phonon mode.
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5

Kaczmarek, Michał, and Ernest Stano. "Magnetic Flux Density under Single Harmonic Distortion." Materials Science Forum 1034 (June 15, 2021): 151–57. http://dx.doi.org/10.4028/www.scientific.net/msf.1034.151.

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In the paper the change of the magnetic flux density under single harmonic distortion is discussed. Presented results show the dependence of the value of the magnetic flux density in the toroidal magnetic core made from the Ni80Fe20 tape of the phase angle of higher harmonic in relation to the main harmonic of distorted magnetizing current. Moreover, the influence of higher harmonic depends from it frequency and it becomes undetectable above 15th higher harmonic, even if its level reaches 50% of the RMS value of the main harmonic of distorted magnetizing current. Laboratory tests were carried out for the magnetic toroidal core of iCT with a current ratio equal to 300 A / 5 A. The oscilloscope is used to measure waveforms of the excitation current and the secondary voltage through the voltage probes. Build in numerical integration is used to determine the magnetic flux density from secondary voltage. In the case of tested 5th higher harmonic the highest value of the magnetic flux density is obtained for phase angle equal to 90° between main and higher harmonics, while the lowest is obtained for 270°. This depends from the initial phase of the magnetic field strength and results from the integration of distorted secondary voltage with the particular content of higher harmonics.
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6

Park, Sang-Cheol, Hee-Seon Bang, and Woo-Jae Seong. "Effects of Material Properties on Angular Distortion in Wire Arc Additive Manufacturing: Experimental and Computational Analyses." Materials 13, no. 6 (March 19, 2020): 1399. http://dx.doi.org/10.3390/ma13061399.

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Анотація:
In wire arc additive manufacturing (AM), as in arc welding, arc heat thermally deforms substrates and articles. For industrial applications, deformation characteristics of various materials must be understood and appropriate materials and methods of reducing deformation must be devised. Therefore, angular distortions of different materials were investigated through bead-on-plate welding and finite element analysis. A model that simplifies temperature-dependent properties was developed to establish relationships between thermomechanical properties and angular distortion. A simplified model of temperature-dependent properties was used, and angular distortion characteristics were extensively investigated for different material properties and heat inputs. Coefficient of thermal expansion, density, and specific heat all notably affected angular distortion depending on heat input conditions. Results showed that during wire arc AM, flatness of both substrates and articles could vary depending on material properties, heat input, substrate thickness, and bead accumulation. Study findings can provide insight into deformation characteristics of new materials and how to mitigate thermal distortions.
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7

Hussein, Rageh K., Ibrahim I. Bashter, Mohamed El-Okr, and Medhat Ahmed Ibrahim. "DFT Investigation of Structural and Electronic Properties of Modified PZT." Acta Chemica Iasi 27, no. 1 (June 1, 2019): 15–30. http://dx.doi.org/10.2478/achi-2019-0002.

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Abstract Density of states and geometrical structures of modified Lead zirconate titanate are investigated using density functional theory within local density approximation. The electronic properties and bond length variation have been studied in terms of electronic structure and bonding mechanism principles respectively. Hybridization between Ti 3d - O 2p states and ferroelectric distortion have been addressed as a theoretical approach, to rule the improvement of ferroelectric properties of Lead zirconate titanate. The analysis of Ga, Tl modified Lead zirconate titanate were found to diminish the hybridization between Ti 3d - O 2p states, the relaxed behavior lead to the reversal of the known ferroelectric distortion. Y, Ho, Yb and Lu modified Lead zirconate titanate compounds have a tendency to intense the ferroelectric stability, its exhibit higher hybridization between Ti 3d - O 2p states than pure Lead zirconate titanate, also the arrangement of the ions distortions is strongly the same as the more favoured ferroelectric states of Lead zirconate titanate.
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8

Birkinshaw, Mark, Josie Rawes, and Diana Worrall. "Extreme jet distortions in low-z radio galaxies." Proceedings of the International Astronomical Union 14, A30 (August 2018): 61–65. http://dx.doi.org/10.1017/s1743921319003466.

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AbstractJets often display bends and knots at which the flows change character. Extreme distortions have implications for the nature of jet flows and their interactions. We present the results of three radio mapping campaigns. The distortion of 3CRR radio galaxy NGC 7385 is caused by a collision with a foreground magnetised gas cloud which causes Faraday rotation and free-free absorption, and is triggered into star formation. For NGC 6109 the distortion is more extreme, creating a ring-shaped structure, but no deflector can be identified in cold or hot gas. Similar distortions in NGC 7016 are apparently associated with an X-ray gas cavity, and the adjacent NGC 7018 shows filaments drawn out beyond 100 kpc. Encounters with substructures in low-density, magnetised, intergalactic gas are likely causes of many of these features.
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9

Bakhtiyarov, Sayavur I. "Numerical Simulations and Experimental Study of Liquid Metal Flow Around Sand Core." Journal of Fluids Engineering 128, no. 3 (October 25, 2005): 541–47. http://dx.doi.org/10.1115/1.2175160.

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This paper presents the results of experimental and numerical studies of the hot distortion phenomenon in the phenolic urethane cold box systems used in metal casting. Dual Pushrod Dilatometry has been used to measure a thermal expansion/contraction of phenolic urethane cold box sand core specimens at temperatures ranging from 20°C to 600°C. High temperature tensile tests showed that the tensile strength of the phenolic urethane cold box sand cores is significantly affected by the bench life, temperature and binders level. High temperature hot distortion furnace tests on cylindrical cores showed that some coatings increase the temperature limit when distortion starts, but application of coating cannot prevent distortion. The hot distortion test during metal casting showed that regardless of the application of coating, the type of coating, and anti-veining additives, all cores with density greater than the density of the molten metal (magnesium alloy) were significantly distorted. Numerical simulations of the liquid metal flow around the cylindrical sand core and analysis of dynamic forces acting on the core during the fill process showed that a buoyancy force is the major contributor to the hot distortion. It is concluded that the one of the solutions in preventing the hot distortion of sand cores is optimizing their weight, which will balance the buoyancy force and will bring the resultant force to the minimum. The hot distortion test castings using optimized sand cores with density almost equal to the density of the molten magnesium proved our predictions, and hot distortion has been prevented.
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10

Bak, Peter, Matthias Schaefer, Andreas Stoffel, Daniel A. Keim, and Itzhak Omer. "Density Equalizing Distortion of Large Geographic Point Sets." Cartography and Geographic Information Science 36, no. 3 (January 2009): 237–50. http://dx.doi.org/10.1559/152304009788988288.

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Дисертації з теми "Density distortion"

1

VERDEROSA, ANTONELLA. "Density and Energy Distortion in an Oscillator Chain." Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2679565.

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The work in this thesis is focused on the thermodynamic properties of microscopic systems in low dimen- sions which are characterized by some peculiar features. In particular we try to understand how the density and the energy of the particles in an oscillator chain can change due to the presence of non equilibrium conditions. This kind of system has been studied widely and deeply: here we choose a different approach and we deal with the problem in a different way. More precisely, instead of considering the dynamics of the chain and its interaction with the reservoirs, we focus on the heat flux that travels through the chain by adding a distorsion to the Hamiltonian that describes the oscillator chain. The chain has fixed edges and equal masses for all particles and it is defined in a phase space of 2N dimensions, with N the number of particles. The work is divided into two part: in the first one we consider for the system a harmonic potential. It is known in literature that not only numerical but also exact analytical solutions already exist in this case. Indeed we use the harmonic chain as a check, to understand if our results are in agreement with the known ones and hence if our model can be consistent. To do this we try to extrapolate the properties of this physical system by computing some basic observables that characterize the chain. We start in Chapter 3 with the analytical computation for a 2-particle system: the quantities taken into account are the kinetic temperature, the variance of the space variables, the average position of the particles and the average of the distance between two particles. We prove for these observables exact solutions exist for this model but only under some constraints on the parameter space. We then study the same observables numerically in Chapter 4 for a 50-particle system by running some Monte Carlo simulations: the results were quite promising: the qualitative behavior of all the quantities considered prove to be similar to the ones known in literature. We consider also the temperature profile to check if the relation hv i 2 i = β 1 < x i+1 − x i > +β 2 still holds for this model: indeed the relation still stands for our model with β 1 = 1 and β 2 having a quadratic dependence on γ. In the second part of the thesis, a new potential is considered: precisely, a α-FPU potential. In this case exact analitycal solutions do not exist yet and hence in Chapter 5 we try to investigate if with this model it is possible to overcome this problem, by computing the same observables as in Chapter 3. this task is indeed not successful, even if some approximated solutions can be obtained by considering a restricted phase space. In Chapter 6 we then run the numerical simulations for the 50-particle system for three different values of k 3 , the coupling constant of the cubic term in the FPU-potential, to understand how the system is changing as we slowly move away from the harmonic case. For k 3 = 0.001 it is straightforward to notice that the behavior is similar to the harmonic case for all variables, while for k 3 = 0.002 and k 3 = 0.003 the trend prove to be more irregular: this is due to a lack of statistics since a higher number of samples is needed in the Monte Carlo simulations for higher values of k 3 . Still, the dependence of these quantities on the non equilibrium conditions, for all the three values is the same as in the harmonic case with the momentum and the variance increasing with the intensity of the distorsion. Finally we study again the temperature profile for the different values of k 3 to comapare the results with the harmonic case: we can see that also the dependence of β 2 on γ is the same, with β 1 = 1 and β 2 with a quadratic dependence on γ and increasing as we move away from the harmonic case.
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2

Bukvic, Gill [UNESP]. "Usinagem a verde voltada à melhoria da distorção e acabamento superficial de cerâmicas sinterizadas." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/96482.

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Made available in DSpace on 2014-06-11T19:28:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-01-18Bitstream added on 2014-06-13T18:57:24Z : No. of bitstreams: 1 bukvic_g_me_bauru.pdf: 10769904 bytes, checksum: 62e0300f452d06ec5fe503cb8b56d8d5 (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A usinagem de cerâmicas avançadas geralmente é feita com o objetivo de corrigir as deformações após a etapa de sinterização, conferir precisão dimensional e qualidade superficial. Para cumprir esta tarefa é utilizada, principalmente, a retificação com rebolo de diamante sob baixas taxas de remoção de material. O torneamento com ferramenta de diamante pode ser aplicado para a maioria das cerâmicas, mas esbarram em condições limites de remoção de material, como profundidade de corte nanamétricas, que se ultrapassadas mudam o regime de remoção de dúctil para frágil. Uma alternativa é a usinagem da peça no estado verde, a qual apresenta fácil usinagem com a diminuição da introdução de defeitos prejudiciais à resistência mecânica. Após a sinterização invariavelmente ocorrem distorções devido à distribuição heterogênea de gradientes de densidade que se localizam nas porções mais externas do compactado. Na tentativa de remover estes gradientes, o presente trabalho analisou a influência da remoção de sobrematerial no estado verde na distorção da peça após a sinterização. Corpos-de-prova de alumina, com 99,8% de pureza, foram torneados com sobremateriais de 1,0, 2,0 3,0, 4,0 e 5,0 mm por uma ferramenta de metal duro sob condições constantes de usinagem. Além da distorção, outras variáveis de saída foram analisadas, com desgaste de ferramenta, força de corte (Fc) e rugosidade média aritmética (Ra) do compactado em verde e sinterizado. Os resultados apontam uma redução da distorção da peça sinterizada de até 81,4% com o maior valor de remoção de sobrematerial em verde e a influência do desgaste da ferramenta na rugosidade da peça em verde e na correspondente peça sinterizada
Advanced ceramics machining is generally done with the objective of correcting distortions in pieces after sintering. In order to comply with this task grinding with a diamond grinding wheel is mainly used with low material removal rates. Turning can be done diamong tool to most of the ceramics, but is runs into very narrow material removal limit conditions, as nanometric cutting depths, which if exceeded change the removal system from ductile to brittle. An alternative is machining the piece on the green state, which presents easy machining without the introduction of harmful defects to mechanical resitance. However, after sintering there are invariably distortions caused by the heterogeneous distribution of density gradients that are located in the most outlying portions of the compacted. In an attempt to remove these gradients, this study examined the influence of different allowance values removed and the corresponding distortion after sintering. Alumina speciments are used for this procedure, with 99,8% purity, from which allowances of 1.0,2.0,3.0,4.0, 5.0 mm are removed by turning with a cermented carbine tool under constant machining conditions. Besides distortion, other output variables were analyzed, such as tool wear, cutting force and surface roughness of the green ceramics and the sintered. The results presents a reduction of the distortion of the sintered piece of 81,4% with the greater allowance removal values and the influence of tool wear on the green machining surface roughness and on the corresponding sintered piece
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3

Ren, Zhensong. "Combined neutron, transport and material based investigation in Ca₃Ir₄Sn₁₃." Thesis, Boston College, 2015. http://hdl.handle.net/2345/bc-ir:104538.

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Thesis advisor: Stephen D. Wilson
This dissertation investigates the cubic type II superconductor, Ca₃Ir₄Sn₁₃, discovered by Remeika and the coauthors more than 30 years ago. It was originally discovered be to a superconductor and later suggested to host ferromagnetic spin fluctuations, which lead to a peak-like anomaly in thermodynamic and transport measurements. Later detailed x-ray single crystal structural refinement associated the peak-like anomaly in transport and magnetization measurements with a charge density wave phase transition at the same temperature. The potential charge density wave phase transition T* can be suppressed either by pressure or chemical potential through substitution on the Ca and Ir site such that a temperature-pressure/composition phase diagram can be constructed. Upon investigating magnetism in this compound, polarized neutron scattering and μSR data from our group and other researchers did not reveal any magnetic order or magnetic spin fluctuations at the time scale of μSR . However, through the partial substitution of Ir by Rh, we realized a structural quantum critical point at ambient pressure with 30% of Ir substituted by Rh--providing the research community a valuable material's platform for studying the interplay between 3D charge density wave order and superconductivity. On the other hand, our surprising discovery of the weak HHL (L=odd) type of super-lattice peaks from neutron scattering led us to a tentative model of a distorted Ca sublattice in this material. The similarity of the lattice instabilites of the Remeika compound and A15 superconductors are discussed, which may give us more insight into its role in the formation of the superconducting phase
Thesis (PhD) — Boston College, 2015
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Physics
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4

Bukvic, Gill. "Usinagem a verde voltada à melhoria da distorção e acabamento superficial de cerâmicas sinterizadas /." Bauru : [s.n.], 2011. http://hdl.handle.net/11449/96482.

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Анотація:
Orientador: Luiz Eduardo de Angelo Sanchez
Banca: Carlos Alberto Fortulan
Banca: Gilberto de Magalhães Bento Gonçalves
Resumo: A usinagem de cerâmicas avançadas geralmente é feita com o objetivo de corrigir as deformações após a etapa de sinterização, conferir precisão dimensional e qualidade superficial. Para cumprir esta tarefa é utilizada, principalmente, a retificação com rebolo de diamante sob baixas taxas de remoção de material. O torneamento com ferramenta de diamante pode ser aplicado para a maioria das cerâmicas, mas esbarram em condições limites de remoção de material, como profundidade de corte nanamétricas, que se ultrapassadas mudam o regime de remoção de dúctil para frágil. Uma alternativa é a usinagem da peça no estado verde, a qual apresenta fácil usinagem com a diminuição da introdução de defeitos prejudiciais à resistência mecânica. Após a sinterização invariavelmente ocorrem distorções devido à distribuição heterogênea de gradientes de densidade que se localizam nas porções mais externas do compactado. Na tentativa de remover estes gradientes, o presente trabalho analisou a influência da remoção de sobrematerial no estado verde na distorção da peça após a sinterização. Corpos-de-prova de alumina, com 99,8% de pureza, foram torneados com sobremateriais de 1,0, 2,0 3,0, 4,0 e 5,0 mm por uma ferramenta de metal duro sob condições constantes de usinagem. Além da distorção, outras variáveis de saída foram analisadas, com desgaste de ferramenta, força de corte (Fc) e rugosidade média aritmética (Ra) do compactado em verde e sinterizado. Os resultados apontam uma redução da distorção da peça sinterizada de até 81,4% com o maior valor de remoção de sobrematerial em verde e a influência do desgaste da ferramenta na rugosidade da peça em verde e na correspondente peça sinterizada
Abstract: Advanced ceramics machining is generally done with the objective of correcting distortions in pieces after sintering. In order to comply with this task grinding with a diamond grinding wheel is mainly used with low material removal rates. Turning can be done diamong tool to most of the ceramics, but is runs into very narrow material removal limit conditions, as nanometric cutting depths, which if exceeded change the removal system from ductile to brittle. An alternative is machining the piece on the green state, which presents easy machining without the introduction of harmful defects to mechanical resitance. However, after sintering there are invariably distortions caused by the heterogeneous distribution of density gradients that are located in the most outlying portions of the compacted. In an attempt to remove these gradients, this study examined the influence of different allowance values removed and the corresponding distortion after sintering. Alumina speciments are used for this procedure, with 99,8% purity, from which allowances of 1.0,2.0,3.0,4.0, 5.0 mm are removed by turning with a cermented carbine tool under constant machining conditions. Besides distortion, other output variables were analyzed, such as tool wear, cutting force and surface roughness of the green ceramics and the sintered. The results presents a reduction of the distortion of the sintered piece of 81,4% with the greater allowance removal values and the influence of tool wear on the green machining surface roughness and on the corresponding sintered piece
Mestre
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5

Mohamed, Fathi Husain Alhadi. "Mitigation of Amplitude and Phase Distortion of Signals Under Modified Von Karman Turbulence Using Encrypted Chaos Waves." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1467943201.

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6

Ramer, Becky E. (Becky Ellen). "Aerodynamic response of turbomachinery blade rows to convecting density distortions." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/49964.

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7

Padilha, Antonio Claudio Michejevs. "Aglomerados de pentaceno e nanotubos de carbono: um estudo MM/MQ (mecânica molecular/mecânica quântica)." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-26042012-145354/.

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Анотація:
Nanotubos de carbono e polímeros condutores são fortes candidatos à miniaturização dos componentes eletrônicos disponíveis atualmente. Estudos teóricos afirmaram que 1/3 dos nanotubos seriam metálicos, enquanto que os outros seriam semicondutores, mas alguns grupos reportaram medidas experimentais evidenciando um pequeno gap eletrônico em tubos considerados metálicos. Protótipos de transístores compostos de nanotubos e moléculas orgânicas conjugadas foram propostos e foi observado que o recobrimento dos tubos por moléculas de pentaceno tornava os dispositivos menos suscetíveis à deposição de impurezas, o que diminuía a histerese na curva característica i x V, ao mesmo tempo que a formação de cristais de pentaceno era favorecida. Neste trabalho estudamos a estrutura eletrônica dos nanotubos (5,5) e (9,0) través de DFT e observamos presença de um gap nesses sistemas, assim como uma deformação de suas estruturas de ligações químicas, evidenciando a distorção de Peierls. O efeito do termo de troca de Hartree-Fock introduzido no funcional B3LYP foi avaliado variando-se seu peso e observando as propriedades destes sistemas. Em uma segunda etapa, utilizamos mecânica molecular e dinâmica molecular clássica com o campo de forças CVFF 950 e observamos a formação de estruturas de pentaceno em volta dos tubos, evidenciando o favorecimento da formação de cristais do mesmo quando depositado sobre os nanotubos.
Carbon Nanotubes and conducting polymers are strong candidates for use in nanoscale electronic devices. Theoretical studies claimed that 1/3 of the nanotubes are metallic, while the others are semiconductors, but some groups have reported experimental measurements of a small electronic gap in tubes considered metallic. Prototype transistors made of nanotubes and organic conjugated molecules were proposed and it has been noticed that the coverage of the tubes by pentacene molecules made those trasistors less susceptible to impurity deposition, reducing the hysteresis in the characteristic I x V curve, while the formation of pentacene cristals was favored. In this work, we studied the electronic structure of the nanotubes (5,5) and (9,0) using DFT and noticed an electronic gap in those systems, as well as a deformation of their structures, similar to a Peierls distortion. The effect of the Hartree-Fock exchange included in the B3LYP functional was studied, as we varied its weight to obtain some properties of those systems. Later, we used molecular mechanics and classical molecular dynamics with the CVFF 950 force field and obtained structures compatible with pentacene crystals around the tubes, showing that the tubes in fact favor the formation of of these structures around them.
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8

Kluender, Rafael. "Mesures en trois dimensions des distorsions cristallines par imagerie en diffraction de Bragg : application aux cristaux de glace." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00635598.

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La déformation visco-plastique de la glace est fortement anisotrope, le plan de glissement préferé étant la plan de base. Le fait que dans un polycristal chaque grain possède sa propre direction de déformation produit des incompatibilités et un champ de contrainte complexe. La déformation à été étudiée expérimentellement en mésurant la dis- tortion des plans cristallins de mono- et polycristaux de glace artificielle. Les expériences ont été réalisées à l'aide d'un faisceau synchrotron. Une nouvelle procédure éxperimental, basée sur les méthodes de l'imagerie en diffraction de Bragg, comme lumière blanche, im- agerie sur la courbe de diffraction et topographie laminaire et ponctuelle, a été dévéloppée. Les désorientations angulaires, les largeurs à mi-hauteur et les intensités intégrées ont été mésurées dans les trois dimensions spatiales de l'échantillon et avec une résolution de 50× 50 × 50µm3. Les algorithmes d'analyse de données ont été écrits pour extraire des données des résultats quantitatifs, et pour calculer les neuf composantes du tenseur de courbure ainsi que la distortion entière des plans cristallins. Les résultats ont permis d'observer les premières étappes de la déformation de la glace. Par example la polygonisation d'un grain à été observée.
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9

Šperbelis, Gediminas. "Rašalinio spausdintuvo spalvų gamos tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2005. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2005~D_20050621_092021-21158.

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It was investigated the colour reproduction on prints made in ink-jet printer. Experimentally investigated gradation characteristics of CMYK colours. It was made a 26 step strip with raster dots from 0 to 100 %. Prints were made at different printing regimes on papers with different whiteness. Zone optical densities were measured, compared with theoretical density values and gradational distortions were determined. Also were measured 100% raster strips in CIE L*a*b* coordinate system and defined the maximum reproduction of colours in ink-jet printer.
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10

Kleprlík, Luděk. "Vlastnosti slabě diferencovatelných funkcí a zobrazení." Doctoral thesis, 2014. http://www.nusl.cz/ntk/nusl-342351.

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We study the optimal conditions on a homeomorphism f : Ω → Rn which guarantee that the composition u◦f is weakly differentiable and its weak derivative belongs to the some function space. We show that if f has finite distortion and q-distortion Kq = |Df|q /Jf is integrable enough, then the composition operator Tf (u) = u ◦ f maps functions from W1,q loc into space W1,p loc and the well-known chain rule holds. To prove it we characterize when the inverse mapping f−1 maps sets of measure zero onto sets of measure zero (satisfies the Luzin (N−1 ) con- dition). We also fully characterize conditions for Sobolev-Lorentz space WLn,q for arbitrary q and for Sobolev Orlicz space WLq log L for q ≥ n and α > 0 or 1 < q ≤ n and α < 0. We find a necessary condition on f for Sobolev rearrangement invariant function space WX close to WLq , i.e. X has q-scaling property. 1
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Книги з теми "Density distortion"

1

Yan, Charles Xiao Bo. Correction of gradient distortion for low frequency current density imaging. 2006.

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2

Rakhit, A. K. Heat Treatment of Gears. ASM International, 2000. http://dx.doi.org/10.31399/asm.tb.htgpge.9781627083478.

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Heat Treatment of Gears: A Practical Guide for Engineers describes the processes and procedures used to harden alloy steel gears and explains how to optimize benefits, such as improved fatigue life, while minimizing distortion and costs. The first few chapters familiarize readers with the basic concepts of heat treating and its effect on the composition, structure, and properties of iron-carbon alloys. The chapters that follow compare and contrast the heat treatments typically used for gears, including through hardening, induction hardening, carburizing, nitriding, and carbonitriding. Carburizing and nitriding are covered in much greater depth than the other methods because of their extensive use and the advantages they offer. As the book explains, carburizing produces gears with three to four times the torque density than that achieved by other methods, while nitriding causes the least amount of distortion. The book also addresses the disadvantages of each process and, using examples, presents various ways to get around them. It also discusses secondary operations, such as shot peening and finish grinding, and provides insights on material and process selection as well as gear design. For information on the print version, ISBN 978-0-87170-694-2, follow this link.
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3

Launay, Jean-Pierre, and Michel Verdaguer. Basic concepts. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198814597.003.0001.

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The electronic structure of molecules is described, starting from qualitative Molecular Orbital (MO) theory. After the case of simple atoms and molecules, one treats molecular solids and develops the relation between Molecular Orbital theory and band theory. In both cases, one shows that the electronic structure can influence the geometrical structure, through Jahn–Teller effects or Peierls distortion. The effect of interelectronic repulsion, the central problem of Quantum Chemistry, is put in perspective by a synthetic presentation of different approaches: Hartree–Fock Self-Consistent Field with treatment of electron correlation, Valence Bond models, and finally Density Functional Theory methods (DFT). The last section is devoted to quantum tunnelling and its dynamical aspects.
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4

Levesque, Paul H., and Laura Sheiman. One-View Asymmetry. Edited by Christoph I. Lee, Constance D. Lehman, and Lawrence W. Bassett. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190270261.003.0013.

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This chapter, appearing in the section “Asymmetry, Mass, and Distortion,” will discuss the presence of tissue asymmetry visualized only on one view. The distribution of fibroglandular tissue is extremely variable and unique from one patient to another; however, in most patients the parenchyma is usually distributed within the breasts symmetrically in a “mirror-image” fashion. Areas of tissue density (asymmetry) may be seen that are only visualized on the craniocaudal (CC) or mediolateral oblique (MLO) view. In the majority of patients, this finding represents superimposed normal tissue, or islands of normal parenchyma. Occasionally, underlying benign lesions may present as a tissue asymmetry. Rarely, a one-view asymmetry may represent a malignancy. This section will discuss the imaging features (including mammography, tomosynthesis, and ultrasound assessment), clinical features, differential diagnosis, and management suggestions for one-view asymmetries.
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5

Prince, Erin L., and Heidi R. Umphrey. Multiple Irregular Masses. Edited by Christoph I. Lee, Constance D. Lehman, and Lawrence W. Bassett. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190270261.003.0026.

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Irregular masses seen on two-view mammography are defined as masses with margins that are neither round nor oval. They may demonstrate indistinct, microlobulated, obscured, or spiculated margins and have a variety of densities, ranging from high to low or fat density. Irregular masses tend to imply a more suspicious finding. Multiple irregular masses may be seen unilaterally or bilaterally, and are usually further evaluated with either ultrasound or magnetic resonance imaging and correlated with clinical information. The etiology of multiple irregular masses is vast. This chapter, appearing in the section on asymmetry, mass, and distortion, reviews the key imaging and clinical features, imaging protocols and pitfalls, differential diagnoses, and management recommendations for multiple irregular masses. Topics discussed include metastases, granulomatous mastitis, diabetic mastopathy, and second synchronous cancers.
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Частини книг з теми "Density distortion"

1

Yu, Mujian, Junwei Luo, Bozhi Xu, Guoliang Chen, and Wei Lu. "Halftone Image Steganography Based on Minimizing Distortion with Pixel Density Transition." In Lecture Notes in Computer Science, 424–36. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-78612-0_34.

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2

Ang, Zoey Z. Y., Rob Heard, Mohammad A. Rawashdeh, Patrick C. Brennan, Warwick Lee, and Sarah J. Lewis. "Breast Asymmetry, Distortion and Density Are Key Factors for False Positive Decisions." In Breast Imaging, 307–15. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-41546-8_39.

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3

Ardestani, Masoud, and Hamid Reza Izadfar. "Reduction of Air-Gap Flux Density Distortion for a 20 kW HTS Induction Motor." In Technological Innovation for Digitalization and Virtualization, 167–83. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-07520-9_16.

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4

Zlatar, Matija, Jean-Pierre Brog, Alain Tschannen, Maja Gruden-Pavlović, and Claude Daul. "Density Functional Theory Study of the Multimode Jahn-Teller Effect – Ground State Distortion of Benzene Cation." In Vibronic Interactions and the Jahn-Teller Effect, 25–38. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-2384-9_2.

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5

Harischandra, Najini, Nihal Kodikara, K. D. Sandaruwan, G. K. A. Dias, and Maheshya Weerasinghe. "Real-Time Simulation of Aero-optical Distortions Due to Air Density Fluctuations at Supersonic Speed." In Neural Information Processing, 653–62. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-26555-1_74.

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6

King, R. B., I. Silaghi-Dumitrescu, and A. Kun. "A Density Functional Theory Study of Distortions from Octahedral Symmetry in Hypoelectronic Six-Vertex Polyhedral Clusters of the Group 13 Elements Boron, Indium, and Thallium." In ACS Symposium Series, 208–25. Washington, DC: American Chemical Society, 2002. http://dx.doi.org/10.1021/bk-2002-0822.ch015.

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7

Abdelouahad, Abdelkaher Ait, Mohammed El Hassouni, Hocine Cherifi, and Driss Aboutajdine. "A New Image Distortion Measure Based on Natural Scene Statistics Modeling." In Geographic Information Systems, 616–30. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-2038-4.ch037.

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In the field of Image Quality Assessment (IQA), this paper examines a Reduced Reference (RRIQA) measure based on the bi-dimensional empirical mode decomposition. The proposed measure belongs to Natural Scene Statistics (NSS) modeling approaches. First, the reference image is decomposed into Intrinsic Mode Functions (IMF); the authors then use the Generalized Gaussian Density (GGD) to model IMF coefficients distribution. At the receiver side, the same number of IMF is computed on the distorted image, and then the quality assessment is done by fitting error between the IMF coefficients histogram of the distorted image and the GGD estimate of IMF coefficients of the reference image, using the Kullback Leibler Divergence (KLD). In addition, the authors propose a new Support Vector Machine-based classification approach to evaluate the performances of the proposed measure instead of the logistic function-based regression. Experiments were conducted on the LIVE dataset.
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8

"Crystalline Imperfections—Problems and Solutions." In Crystalline Imperfections: Key Topics in Materials Science and Engineering, 13–33. ASM International, 2021. http://dx.doi.org/10.31399/asm.tb.ciktmse.t56020013.

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Abstract This chapter provides readers with worked solutions to more than 25 problems related to compositional impurities and structural defects. The problems deal with important issues and challenges such as the design of low-density steels, the causes and effects of distortion in different crystal structures, the ability to predict the movement of dislocations, the influence of impurities on defects, the relationship between gain size and material properties, the identification of specific types of defects, the selection of compatible metals for vacuum environments, and the effect of twinning planes on stacking sequences. The chapter also includes problems on how the formation of precipitates can produce slip planes and how grain boundaries can act as obstacles to dislocation motion.
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9

"Mechanical Behavior of High-Entropy Alloys—Questions and Answers." In Mechanical Behavior of High-Entropy Alloys: Key Topics in Materials Science and Engineering, 21–47. ASM International, 2022. http://dx.doi.org/10.31399/asm.tb.mbheaktmse.t56030021.

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Abstract This chapter, presented in a question-and-answer format, covers many practical aspects of high-entropy alloys (HEAs). It provides clear and concise answers to more than 50 questions, imparting knowledge on alloying elements, heat treatments, diffusion mechanisms, phase formation, lattice distortion, crystal and grain structures, structure-property relationships, microstructure control, and characterization methods. It likewise explains how to calculate the effect of strengthening processes on the mechanical properties of HEAs and offers insights on how to balance strength, ductility, and density for specific applications. It also provides information on twinning behaviors, stacking faults, elastic properties, coating and film deposition methods, manufacturing challenges, and the use of computational techniques for alloy design.
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10

Saha, Santanu. "Non-Destructive Evaluation of Residual Stresses in Welding." In Engineering Principles - Welding and Residual Stresses. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.101638.

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During welding, due to the highly localized transient heat input, considerable residual stresses and deformations may occur. Welding residual stresses and welding distortion may greatly impair manufacturing and strength. Residual stresses are internal forces without external forces acting. The total residual stresses superimpose on the stresses from the external load, i.e., the load stresses. Residual stresses are the result of microstructural deformations, e.g., dislocations etc. and can be divided as follows: i) volumetric (or “dilatoric”) ii) distortional (or “deviatoric”). Volumetric strain generally is caused by sectioning by thermal expansion, chemical conversion, microstructural transformation or change in state; distortional strain is generally caused by time-independent plastic or time-dependent visco-plastic deformation. There are several methods available to measure the residual stresses or strains non-destructively. One of them is X-ray diffraction. X-rays are diffracted crystal lattices and produce interference phenomena, from which it is possible to draw conclusions relating to the interplanar spacing of the lattice. Other methods are the neutron diffraction method, ultrasonic method and the magnetostriction method. In the magnetostriction or Barkhausen noise method, the stress state is deduced from the value of the local magnetization restraint. The magnetic flux density in a ferromagnetic material subjected to a time-varying magnetic field does not change in a strictly continuous way, but rather by small, abrupt, discontinuous increments called Barkhausen jumps. The jumps are due primarily to discontinuous movements of boundaries between small magnetically saturated regions called magnetic domains in the material. This chapter describes the causes and measurement of residual stress induced during welding.
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Тези доповідей конференцій з теми "Density distortion"

1

Goebel, Dan M. "Pulse shortening and distortion in BWO and TWT microwave tubes." In High energy density microwaves. AIP, 1999. http://dx.doi.org/10.1063/1.59016.

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2

Yan, Charles X. B., Tim P. DeMonte, and Michael L. G. Joy. "Gradient Distortion Correction for Low Frequency Current Density Imaging." In Conference Proceedings. Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2006. http://dx.doi.org/10.1109/iembs.2006.260787.

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3

Yan, Charles X. B., Tim P. DeMonte, and Michael L. G. Joy. "Gradient Distortion Correction for Low Frequency Current Density Imaging." In Conference Proceedings. Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2006. http://dx.doi.org/10.1109/iembs.2006.4397384.

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4

Wu, Jingxian, and Ning Sun. "Optimal Sensor Density in a Distortion-Tolerant Linear Wireless Sensor Network." In GLOBECOM 2010 - 2010 IEEE Global Communications Conference. IEEE, 2010. http://dx.doi.org/10.1109/glocom.2010.5683531.

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5

Brandt, Erika, Frank Zimmerer, Bistra Andreeva, and Bernd Möbius. "Mel-Cepstral Distortion of German Vowels in Different Information Density Contexts." In Interspeech 2017. ISCA: ISCA, 2017. http://dx.doi.org/10.21437/interspeech.2017-838.

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6

JOPSON, R. M., T. E. DARCIE, and K. GAYLIARD. "Observation of carrier-density mediated intermodulation distortion in an optical amplifier." In Optical Fiber Communication Conference. Washington, D.C.: OSA, 1988. http://dx.doi.org/10.1364/ofc.1988.wn4.

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7

Nejdl, Jaroslav, and Michaela Kozlová. "Plasma density-gradient measurement using x-ray laser wave-front distortion." In SPIE Optical Engineering + Applications, edited by James Dunn and Gregory J. Tallents. SPIE, 2009. http://dx.doi.org/10.1117/12.837015.

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8

Zhang, Qiaolin, Kameshwar Poolla, and Costas J. Spanos. "Modeling of mask thermal distortion and its dependency on pattern density." In Photomask and Next Generation Lithography Mask Technology XII, edited by Masanori Komuro. SPIE, 2005. http://dx.doi.org/10.1117/12.617442.

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9

Kovacevic, Svjetlana, Tatjana Pesic-Brdanin, and Jovan Galic. "Intermodulation distortion of class D audio amplifier using pulse density modulation." In 2016 Zooming Innovation in Consumer Electronics International Conference (ZINC). IEEE, 2016. http://dx.doi.org/10.1109/zinc.2016.7513652.

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10

Schappert, G. T., D. E. Casperson, J. A. Cobble, L. A. Jones, G. A. Kyrala, P. H. Y. Lee, T. D. Nichols, A. J. Taylor, and C. R. Tallman. "Ultra-high Intensity Lasers and Experiments at Los Alamos." In High-Energy Density Physics with Subpicosecond Laser Pulses. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/hpslp.1989.t5.

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Recent developments in excimer laser technology have made it possible to achieve irradiances on target approaching 1020 W/cm2. Oscillators capable of generating subpicosecond pulses and amplifiers capable of amplifying these pulses without significant pulse stretching or optical distortion are now available. Hence ultrashort pulses of modest energies, focused to nearly-diffraction-limited spots a few microns in diameter, result in an irradiance in excess of 1019 W/cm2. Such laser systems typically operate at a repetition rate of several Hz, ideal for experimental programs.
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