Volume Distortion Research Articles

Effects on magnetic properties and light absorption bandgaps of lattice distortions in CuIn1-xCoxSe2 chalcopyrites

Co doped CuInSe2 compounds have been synthesized by vacuum arc melting-vacuum solid sintering-mechanical milling technology, and their crystal structures, magnetic and light absorption properties have been systematically investigated by using X-ray diffraction, vibrating sample magnetometer and UV–Vis spectrophotometer. X-ray diffraction analyses show that CuIn1-xCoxSe2 (x = 0–0.2) crystallize in tetragonal chalcopyrite structure with a space group of I4¯2d. Co partly substitutes for In at the 4b site. The studies of magnetic properties show that CuIn1-xCoxSe2 (x = 0.1–0.3) show supermagnetic characteristics at room temperature with applying an external field. Co doping can adjust the light absorption bandgaps of CuIn1-xCoxSe2 from 1.25 to 1.53eV. These phenomena are revealed to be closely correlated with the lattice distortions induced by Co doping into CuInSe2. The magnetism of Co doped CuInSe2 is suggested to come from the double-exchange mechanism. The magnetic moment and light absorption bandgap depend upon the lattice distortions of (In,Co)Se4 and CuSe4 tetrahedrons, it shows that the magnetic moment is going up with the increase of Se-(In,Co) bond length and the decrease of (In,Co)Se-(In,Co) bond angle; the light absorption bandgap is going up with the increase of volume distortion of CuSe4 tetrahedron.

Geometry-based distortion measures for space deformation

We present a framework for optimizing a rich family of geometry-based energies defined on planes, surfaces and volumetric domains. Our approach is based on the concept of first order distortion measures and on the steepest descent optimization. Specifically, we present an algorithm for inducing optimal deformations for triangular and tetrahedral meshes. The resulting techniques apply to a variety of geometry processing problems, including ones that are highly non-convex. Among these problems are deformation and parametrization of planes, surfaces and volumetric meshes, surface mapping using volumetric textures, generation of triangular and tetrahedral meshes. In particular, the proposed techniques can be employed to devise “as close to being conformal as possible” mappings and other deformations that are nearly optimal with respect to related distortion measures, such as the isometric distortion and the distortion of a local volume. Tests, carried out on 2D and 3D data, show that the optimization process is numerically stable and fast-converging. Our approach is general and it can be run in parallel processes.

Evaluation of microdamage initiation in Z-pinned laminates by means of automated RVE computations

Z-pinning was originally designed to improve the delamination toughness and the impact resistance of composite laminates. However, there is extensive experimental evidence that this improvement is accompanied by a reduction of the in-plane properties. The main mechanisms responsible for this deterioration are the local change in fiber content, fiber distortion, and the inclusion of resin-rich regions near the Z-pin. The shape of these geometrical features strongly depends on the laminate stacking sequence and on pin parameters such as pin diameter, pin content, and initial pin inclination angle. Their shape complexity challenges analytical modelling approaches which are currently used to generate RVE geometries for simulations.A computational approach is presented to generate such geometrical models. Resin-rich regions are modelled by initially straight discretized lines which are gradually shaped by a set of geometrical operations mimicking pin insertion, pin rotation and fiber deflection. Fiber distortion is modelled in a post-processing stage in cross-sections accounting for the preservation of the amount of fibers. These models are then transformed into finite element mechanical models in order to investigate how local fiber volume fraction changes, fiber misalignment, or distortions in reinforcement due to pin rotation, affect the global stiffness and local stress concentrations.

Bi-Sobolev solutions to the prescribed Jacobian inequality in the plane with Lp data and applications to nonlinear elasticity

We construct planar bi-Sobolev mappings whose local volume distortion is bounded from below by a given function f∈Lp with p>1. More precisely, for any 1<q<(p+1)/2 we construct W1,q-bi-Sobolev maps with identity boundary conditions; for f∈L∞, we provide bi-Lipschitz maps. The basic building block of our construction are bi-Lipschitz maps which stretch a given compact subset of the unit square by a given factor while preserving the boundary. The construction of these stretching maps relies on a slight strengthening of the celebrated covering result of Alberti, Csörnyei, and Preiss for measurable planar sets in the case of compact sets. We apply our result to a model functional in nonlinear elasticity, the integrand of which features fast blowup as the Jacobian determinant of the deformation becomes small. For such functionals, the derivation of the equilibrium equations for minimizers requires an additional regularization of test functions, which our maps provide.

Crystal chemistry of K-rich nepheline in nephelinite from Hamada, Shimane Prefecture, Japan

AbstractK-rich nepheline with a structural formula of A2B6T14T24T34T44O32 (Z = 1) within melilite–olivine nephelinite from Hamada, Shimane Prefecture, Japan, was investigated to clarify its crystal structure and to determine cation distributions in the A and B structural positions of structural channels and tetrahedral T1–T4 sites. The chemical formula of a single-crystal sample was (Na5.437K2.248Mg0.034Ca0.031)Σ7.750(Si8.332Al7.445Fe3+0.158Ti0.009Cr0.005)Σ15.949O32, which results in 65.2, 27.8, 2.1, 3.2 and 1.6 mol.% NaAlSiO4, KAlSiO4, NaFe3+SiO4, □Si2O4 and □0.5(Ca,Mg)0.5AlSiO4 end-member components, respectively, where □ is a vacancy. X-ray diffraction data of a single crystal with dimensions of 0.28 mm × 0.15 mm × 0.05 mm measured at 296 K indicate the space group P63. In the structural refinement, the R1 factor was reduced to 3.69% by taking twinning by merohedry into the refinement. The refinement accounted for 77.7% of the absolute structure and 22.3% of the a and b axes reversed absolute structure. The atomic populations determined in the A and B positions were 1.834 K + 0.166 □ and 5.705 Na + 0.198 K + 0.031 Ca + 0.034 Mg, respectively, implying the substitution of K for Na in the B position. The a and c dimensions are a = 10.0270(3) and c = 8.4027(3) Å. The average &amp;lt;A–O&amp;gt; and &amp;lt;B–O&amp;gt; distances are 3.009 and 2.65 Å, respectively. The substitution of K for Na in the B channel results in increased volume and bond-length distortion of the BO8 polyhedra, which then reduces distortion of the AO9 polyhedra. The average T–O distances indicate that the T1 and T4 sites are essentially filled with Al, whereas the T2 and T3 are filled with Si. Despite the deviation of the O1 oxygen from the triad axis and the combination of K+ ions and vacancies in the hexagonal channels, an incommensurate structure was not observed in the X-ray diffraction data or using the electron diffraction technique.

Research on Supply Chain Coordination and Profit Allocation Based on Altruistic Principal under Bilateral Asymmetric Information

To ensure supply chain coordination and equitable profit allocation when there is bilateral asymmetric information, a supply chain consisting of one manufacturer with private manufacturing cost information and one retailer with private selling cost information is considered. A bilateral adverse selection model is established with a virtual altruistic principal as the coordination subject, for which the supply chain coordination conditions and an allocation rule for the supply chain surplus are then given. It was found that contract coordination depended on the costs and risk rates of both parties and market demand; that is, the lower the costs and the risk rate, the easier the supply chain coordination. Second, the trading volume distortion degree was positively correlated with production cost, sales cost, and price sensitivity and negatively correlated with the market environment parameter. Third, the allocation proportion for the supply chain surplus was determined. Finally, under a specific cost distribution assumption, a numerical example was given to simulate the contract execution and analyze the relationships between costs and profit.

Colour identification, degradation processes and findings in a fifteenth-century Book of Hours: the case study of Cofre n.\xba 31 from Mafra National Palace

This paper presents the work done as part of a master dissertation on Conservation and Restoration at the Faculty of Sciences and Technology, Nova University of Lisbon. The “Cofre n.º 31” is a French fifteenth century Book of Hours from the Library of the National Palace of Mafra, Portugal. This prayer book, composed by illuminations and devotional texts, was in bad condition due mainly to the rebinding done between eighteenth and nineteenth centuries. According to the assessment of the state of conservation, the main damages observed in the text block and binding were: volume distortion, loose and deformed gatherings, distortion and cockling of folios, and damages in the illuminations. The pigments palette was identified by µ-EDXRF, FORS, µ-Raman and µ-FTIR, which is consistent with the materials used in the fifteenth century. Nevertheless, some particular application techniques such as mixtures and overlays were found, namely in the red colours and specifically in the metallic leaves. Some of these colours also show specific degradation: darkening of the mixture of minium and vermillion; silver tarnishing with strong migration into the parchment support, especially when associated with minium; detachment of azurite, lead white and its mixtures, such as flesh tones and light colours. The main deterioration processes associated to silver and pigments can be assigned to their reactions with humidity and air pollutants, to the grain size of the pigments and to mechanical factors related to the book binding and its use. The presence of different pigments application techniques in different groups of folios lead us to conclude for the existence of a pigments palette with variations, and finally, three different illuminators and two different techniques, confirming the proposals of art history studies.

Synthesis, structure and luminescence of SrLiAl3N4:Ce3+ phosphor

Here we report a new phosphor, Ce-doped SrLiAl3N4, which can be effectively excited by green light at ~ 517 nm. A series of synthetic experiments are performed to find an optimal scheme. This phosphor has two emission bands at ~ 545 and ~ 610 nm corresponding to the d-f electronic transition of Ce3+. Large centroid shift of 5d level results in a green light-excitable feature. Compared to other Ce3+-doped nitrides, the crystal field splitting of 5d energy levels for this phosphor, i.e. about 11,300 cm−1, is much smaller due to larger volume and smaller distortion of coordination polyhedron of Ce3+. The phosphor shows an excellent luminescent thermal quenching behavior. At 150 °C, the emission intensity retains about 93% of the initial value at room temperature upon 517 nm excitation. This property can be ascribed to rigid structure and large gap between 5d levels and bottom of conduction band.

Typology of intravesical prostatic protrusions, or so-called median lobes, in middle-aged and older men.

Changes related to prostatic ageing include an increase of prostate volume and morphologic distortions of the prostatic edges in middle-aged and older men. These changes of the prostate exhibit a certain level of heterogeneity, which is clinically obvious for surgeons, radiologists, and anatomists, and which can be explained by the complex nature of the embryologic/anatomic development of the prostate. While the etiology of the median lobe has typically been attributed to a growth and protrusion of the prostatic area at the top of the utricle, we argue that this is not necessarily the case as intravesical protrusions of the prostate have also been observed laterally and anteriorly to the bladder neck, suggesting the involvement of other prostatic zones, thereby highlighting the need to refine the concept of the median lobe. The current study examined a large series of 478 prostate magnetic resonance imaging scans (MRIs). Intravesical prostatic protrusions were classified, based on their topography: anterior (A), posterolateral (P), and dual (D). Data were analyzed using MedCalc®11.6.1.1.0 software. Pearson's correlations with coefficients (r) and P values were calculated for the patient's age, prostate volume, and IVPP size. An intravesical prostatic protrusion was observed in 27% of cases, with type A occurring in 18% (3% isolated), type P in 96% (81% isolated), and type D in 15%. The new insights regarding the variability in prostate anatomy will contribute to the improved management of prostate hypertrophy by radiologists and surgeons.

Surface distortion compensation in nano particle by using the graphene layer to obtain reconfigurable absorber

Distortion in the fabrication of the nanoparticle in the process of the lithography affects the absorption of a nano antenna. In this paper, we have used the graphene as a part of the substrate for compensating the effect of these distortions. In this study, we have investigated rectangular nano particle as our basic nano particle which are placed over a SiN substrate as a spacer. We have utilized the graphene layer with thickness of 2 nm under the nano particle and then various distortions is modeled and applied by small spherical array. In optical domain, we have studied the effect of distortions on the nano particle reflection. We have checked the graphene effect for compensation the frequency shift that made by the distortions. We also replaced the graphene layer with SiN to show that how much the graphene is affected on reflection controlling. Furthermore the distortion volume has been considered and compared to the rectangular element. The result shows that the relaxation time and temperature have less effect on the absorbency and chemical potential is the main parameter for compensation. This method can be considered for calibration the nano antenna and the optical absorber.

Segregation energy of the hydrogen at Ni Σ3 grain boundaries: some implications of the atomic volume and the interstitial self-stress

Atomistic simulations performed for the hydrogen segregation in different Ni $$ \Sigma 3 $$ 〈110〉 tilt grain boundaries (GBs), including symmetrical and asymmetrical configurations, highlight a decreasing functional relationship between the segregation energy and the atomic volume of the GB interstitial site. The analysis of the local deformations around the hydrogen atoms showed that this relationship is not depending on the geometric form of the GB interstitial sites. For small contents of the volume change, a linear correlation was found between the segregation energy of the hydrogen solutes and the volume occupancy of the GB trapping sites. However, when interstitial volumes reach a certain critical value this proportionality presents some limits, especially for GB trapping sites that undergo considerable volume distortions. A general thermo-mechanical framework based on the atomic self-stress calculations is stated to understand locally the connection between the volume occupancy and the elastic relaxed energy from the insertion of hydrogen interstitials in $$ \Sigma 3 $$ grain boundaries.

Effect of temperature and stoichiometry on the long-range 1:2 cation order in BaZn1/3Ta2/3O3

We report on the compositional stability range, the degree of atomic order and Raman and optical spectra of the off-stoichiometric BaZn1/3Ta2/3O3 (BZT) within the BaO–ZnO–Ta2O5 ternary diagram. Almost all off-stoichiometric BZT compositions equilibrated at 1200 °C show significant degree of the long-range 1:2 cation order ranging from 60% to 80%. Ceramics equilibrated at 1550 °C and annealed at 1450 °C show strong effect of composition on the 1:2 order. The regions where an 1:2 atomic order is robust to the deviation from stoichiometry include the off-stoichiometric compositions along the BZT–Ba4Ta2O9, BZT–Ba3Ta2O8, BZT–BaTa2O6, BZT–Ta2O5, BZT–ZnTa2O6 and BZT–Zn4Ta2O9 (pseudo) tie lines. At the same time ceramics formulated along the BZT–BaO, BZT–ZnO, BZT–BaZnO2, BZT–Ba2ZnO3 tie lines and BZT–‘Ba3ZnO4’ pseudo tie line show complete disorder. There is a very close correlation between the degree of the 1:2 order on one hand and the unit cell volume and lattice distortion on the other hand. The ordered BZT show contraction of the unit cell whereas disordered ceramics show expansion of the unit cell in the off-stoichiometric region. The pronounced signatures of the order-disorder phase transition in the Raman and optical spectra are discussed.

Assessment of Volumetric Distortion Artifact in Filled Root Canals Using Different Cone-beam Computed Tomographic Devices

IntroductionArtifacts in cone-beam computed tomographic (CBCT) imaging may compromise radiodiagnosis. Obturation materials for endodontic treatment may present with variable material density and thus also cause distinct artifact expression. The aim of this study was to assess the volume distortion artifact of root canal sealers using CBCT devices and micro-CT imaging as a reference. MethodsThirty single-root mandibular central incisors were used for this study. Teeth were prepared with EndoSequence rotary nickel-titanium files (Brasseler USA, Savannah, GA) and divided into 3 groups. Canals were obturated with gutta-percha and AH Plus root canal sealer (Dentsply Maillefer, Ballaigues, Switzerland) using single-cone filling techniques. Each tooth was scanned with different CBCT devices (ie, Promax 3D Max [Planmeca Inc, Roselle, IL], NewTom VGi evo [NewTom, Verona, Italy], and 3D Accuitomo 170 [J Morita, Kyoto, Japan]) with the same voxel size (0.2 mm3) and compared with micro-CT imaging as a reference standard. ResultsThe results showed a significant difference in terms of volume distortion between micro-CT and CBCT images (P < .05). There were also significant differences among CBCT devices. Promax 3D Max measurements showed significantly larger root canal volumes than the other CBCT machines (P < .05). However, NewTom VGi evo and 3D Accuitomo 170 showed similar results without any significant difference (P > .05). ConclusionsCBCT devices showed more volumetric distortion artifact than micro-CT imaging. The volume was variable for different CBCT devices while scanning at the same voxel size. However, to assess the effect of sealer materials on CBCT imaging, further studies should be conducted for different sealers.

Investigating nanoscale mineral compositions: IronL3-edge spectroscopic evaluation of iron oxide and oxy-hydroxide coordination

The iron (Fe) L 2,3 -edge X-ray absorption near-edge structure (XANES) spectrum is sensitive to the local coordination environment around the Fe metal center, making it a useful probe for understanding Fe mineral speciation. The two dominant spectral peaks in the Fe L 3 -edge are parameterized according to the difference in the energy position (ΔeV), and the quotient (intensity ratio) of the two peaks’ maxima. Variations in the ΔeV value are strongly linked to factors that impact on the strength of the ligand field (e.g., Fe valence state, coordination number, and the nature of ligand bonding). The intensity ratio is affected by the strength of the ligand field and by the composition of the resultant molecular orbitals. The Fe valence state also strongly affects the intensity ratio, and an intensity ratio equal to one can be used to distinguish between Fe 2+ and Fe 3+ minerals. The effects of polyhedral distortion on the magnitudes of ΔeV and intensity ratio values were tested by considering the Fe oxide and -oxy-hydroxide mineral system, in which ligand effects are limited to the differences between the oxygen and hydroxyl ligands. In this system, the distribution of Fe oxide and -oxy-hydroxide minerals on a ΔeV vs. intensity ratio two-parameter plot could be explained by considering the Fe valence state, the ligand chemistry and the site symmetry of the Fe polyhedra. Furthermore, the ΔeV and intensity ratio values were found to be anti-correlated with respect to the various distortion measures considered in this study (e.g., polyhedral volume distortion percentage). This two-parameter plot is thus presented as a standard-less phase-specific identification tool for use in Fe speciation studies, applicable to both natural systems (e.g., aerosols, aquatic colloids) as well as to engineered systems (e.g., nanoparticle synthesis). A major advantage of this technique is that it is applicable to both crystalline and poorly crystalline phases, thus enhancing our ability to study amorphous and nano-crystalline phases that are typically difficult to characterize using X-ray diffraction techniques.

Trading Volume and Price Distortion: An Agent-Based Model with Heterogenous Knowledge of Fundamentals

This paper investigates whether trading volume and price distortion can be explained by the investor’s bounded rationality. Assuming that agents are bounded by their information access and processing, what are the consequences on market dynamics? We expose the result of simulations in an ABM that considers the liquidity as an endogenous characteristic of the market and allows to design investors as bounded rational. In a call auction market, where two risky assets are exchanged, traders are defined as a mix between fundamentalist and trend-follower outlook. Each one differs as to behaviour, order-placement strategy, mood, knowledge, risk-aversion and investment horizon. We place agents in a context of evolving fundamental values and order placement strategy; they perceive the fundamental but they also have some heterogeneous belief perseverance; and they adapt their orders to the market depth so as to maximise their execution probability and their profit. By adding bounded rationality in their information processing, we show that (1) usual features as trend-follower outlook and heterogeneous investment horizon are important features to generate excess volatility of asset prices and market inefficiency; (2) the learning fundamental value stabilises the market price and the trading volume; (3) the order-placement strategy increases trading volume, but reduces market efficiency and stability; (4) the agent’s mood prevents illiquid market and weakly increases the market volatility as classical noise trader agents; (5) the impatience to sell of traders is always present in the market: the market sell orders are always more numerous than the market buy orders.

Breast amyloidosis: a case report

Amyloidosis is an uncommon disorder characterized by extracellular deposition of abnormal proteins. Breast involvement has rarely been reported and can clinically be misdiagnosed as breast cancer. A 60-year-old woman presented with a 3-mm diameter mass in the right breast close to a silicon implant positioned 20 years before. A core biopsy, performed to rule out breast cancer, showed amyloid deposit. Further exams confirmed a systemic amyloid light chain amyloidosis. After few months the mass increased causing breast volume and shape distortion. Since breast cancer may be the cause of amyloid deposits or be hidden by it, the patient underwent a bilateral skin sparing mastectomy and expander and fat grafting breast reconstruction. The resection specimens showed amyloid deposits only, no evidence of cancer. At 2 years follow-up, no breast amyloidosis recurrence was shown. Breast amyloidosis is rare but can occur in a plastic surgeon’s practice. It is mandatory to rule out a comitant breast cancer or systemic amyloidosis.

Volume distortion in homotopy groups

Given a finite metric CW complex $X$ and an element $\alpha \in \pi_n(X)$, what are the properties of a geometrically optimal representative of $\alpha$? We study the optimal volume of $k\alpha$ as a function of $k$. Asymptotically, this function, whose inverse, for reasons of tradition, we call the volume distortion, turns out to be an invariant with respect to the rational homotopy of $X$. We provide a number of examples and techniques for studying this invariant, with a special focus on spaces with few rational homotopy groups. Our main theorem characterizes those $X$ in which all non-torsion homotopy classes are undistorted, that is, their distortion functions are linear.

X-ray topographic study of a diamond from Udachnaya: Implications for the genetic nature of inclusions

In recent years, several studies have focused on the growth conditions of the diamonds through the analysis of the mineral inclusions trapped in them. In these studies, it is crucial to distinguish between protogenetic, syngenetic and epigenetic inclusions. X-ray topography (XRDT) can be a helpful tool to verify, in a non-destructive way, the genetic nature of inclusions in diamond. With this aim, a diamond from the Udachnaya kimberlite, Siberia, was investigated. The diamond, previously studied by Nestola et al. (2011), has anomalous birefringence and the two largest olivines have typical “diamond-imposed” shapes. The study of the topographic images shows that the diamond exhibits significant deformation fields related to post growth plastic deformation. The absence of dislocations starting from the olivine inclusions, and the dark contrasts around them represent the main results obtained by XRDT, contributing to the elucidation of the relationships between the diamond and the olivines at the micron-meter scale. The dark halo surrounding the inclusions was likely caused by the effect of different thermo-elastic properties between the diamond and the inclusions. The absence of dislocations indicates that the diamond-imposed morphology did not produce the volume distortion commonly associated with the entrapment of the full-grown inclusions and, thus, only based on such evidence, a syngenetic origin could be proposed. In addition, stepped figures optically observed at the interface between diamond and one of the olivines suggest processes of selective partial dissolution that would contribute to a change in the final morphology of inclusions. These results show that a diamond morphology may be imposed to a full-grown (protogenetic) olivine during their encapsulation, suggesting that the bulk of the inclusion is protogenetic, whereas its more external regions, close to the diamond-inclusion interface, could be syngenetic.

FCS on Proteins in Crowded Environments

The most of our knowledge about proteins is mainly gained from in-vitro measurements. However, the results obtained from in-vitro measurements are likely to be deviated from the explicit natural characteristics of the proteins in the living cell. Yet, the technical difficulty of labeling proteins inside the living cell hinders carrying out in-vivo fluorescence spectroscopic studies. An approach to get closer to the complex nature of the cellular cytoplasm is to roughly mimic it by an artificial crowded-environment. Fluorescence Correlation Spectroscopy (FCS) is utilized to study diffusion effects of fluorescently labeled molecules. The implication of FCS in studying proteins mobility in a crowded-medium is limited by several technical obstacles such as distortion of the molecule detection volume[1] and switching from Brownian diffusion regime to hindered diffusion[2] regime. A pre-characterization of the viscosity and refractive index of investigated solutions and their effects on the validity of the measurement has been carried out [3]. Further, FCS was utilized to investigate the diffusional phenomena of various proteins dissolved in solutions containing classes of crowders [4].

Suppression of space charge induced beam halo in nonlinear focusing channel

An intense non-uniform particle beam exhibits strong emittance growth and halo formation in focusing channels due to nonlinear space charge forces of the beam. This phenomenon limits beam brightness and results in particle losses. The problem is connected with irreversible distortion of phase space volume of the beam in conventional focusing structures due to filamentation in phase space. Emittance growth is accompanied by halo formation in real space, which results in inevitable particle losses. A new approach for solving a self-consistent problem for a matched non-uniform beam in two-dimensional geometry is discussed. The resulting solution is applied to the problem of beam transport, while avoiding emittance growth and halo formation by the use of nonlinear focusing field. Conservation of a beam distribution function is demonstrated analytically and by particle-in-cell simulation for a beam with a realistic beam distribution.