Range Order Research Articles

Effect of B2O3 and Li2O on vibrational, thermal and optical properties of 50Bi2O3-15PbO-(35-x)B2O3-xLi2O (0 ≤ x ≤ 25 mol%) glasses

Bi2O3 based glasses have been proven as promising optical materials with regard to their 6 s2 lone pair electrons. By melt quenching, the highly thermal stable glasses 50Bi2O3-15PbO-(35-x)B2O3-xLi2O (where 0 ≤ x ≤ 25 mol%) were prepared. The short range order of the glasses was verified with XRD and DSC measurements. DSC analysis showed that thermal parameters varied non-linearly with increase of Li2O. Density (ρ), molar volume (Vm), oxygen packing density (OPD) and oxygen molar volume (Vo) were calculated and their compositional dependency was discussed in detail. Energy dispersive X-Ray (EDX) spectrometry analysis validated the stoichiometry of sample composition. FTIR analysis illustrated that the glass network comprise of BiO3, BiO6, BO3 and BO4 structural units together with non-bridging oxygens. The computed optical properties like optical band gap (Eopt), refractive index (n), Urbach energy (∆E), molar refraction (RM), metallization criterion (M) and oxide ion polarizability (αO2-) were observed to be non-linearly varied with the addition of Li2O. The interplay between the structural roles of Li2O and Bi2O3 was instrumental for the observed variations in all the properties. BiPBL4 glass showed the highest thermal stability (175 °C) and the high kgl value among the glass series. The incorporation of Li2O in presence of low mol% of B2O3 with Bi2O3-PbO endowed these glasses to have the low phonon energy. The analysis carried out in this work showed that these glasses might useful for optoelectronic devices and optical fiber drawing applications.

Evolution of local atomic structure accompanying devitrification of amorphous Ni-Zr alloy thin films

Thin film metallic glasses undergoing devitrification can form partially crystallized or fully crystallized materials with novel structural and magnetic properties. The development of desired and tunable properties of such systems drives the need to understand the mechanism of their thermal evolution at the atomic level. Co-sputtered amorphous Ni-Zr alloy thin films which were thermally annealed in steps of 200°C from room temperature up to 800°C, were observed to undergo an amorphous-to-crystalline transformation. Evolutions in local atomic structure, including oxide formation and depletion during this devitrification process, were determined using a combination of X-ray reflectivity (XRR), grazing incidence X-ray diffraction (GIXRD) and Extended X-ray Absorption Fine Structure (EXAFS) techniques. The most probable phase of the alloy was determined as Ni7Zr2; undergoing a polymorphous transformation. The slight oxide content in the films was also noted to decrease rapidly as annealing proceeded; leaving the crystallization pathway unhindered. modeling and analyses of XRR and GIXRD data showed that film thickness decreased with annealing while long range order increased. Pair distribution function peak widths were observed to decrease with annealing, indicating a control over structural disorder in the system as it transitioned from the amorphous to crystalline state. Partial atomic distribution in the environment of each constituent was examined at every stage of annealing through EXAFS measurements, which gave proper insight into atomic scale changes to the order present. Detailed analyses through these techniques gave coherent results, thus providing a true picture of the thermal evolution process of devitrification in this technologically useful material.

Parametric Optimization of Nozzle Turbine Vane Modal Characteristics by Means of Artificial System

Modal analysis is a fundamental assessment in the design phase of a nozzle guide vane in a low pressure turbine system. Evaluation is crucial for new concept design but also in case of design modification. The technical requirement is to ensure appropriate durability level (number of flight cycles) and the reliability of the system. An understanding of dynamic behavior is one of the key elements in the high cycle fatigue (HCF) evaluation. Finite element method (FEM) analyses are widely used in new product introduction phases to verify modal characteristics with respect to operating range and engine orders (forcing function, excitation). In the process used 2D representation of the nozzle guide vane approximated by axisymmetric and plane stress with thickness FEM plain elements. The optimization process used geometrical parameters (nozzle outer band and casing shell) and surrogate models to find optimal solutions from a frequency placement perspective. A sensitivity analysis and optimization process revealed casing shell thickness to be a major contribution in the modal response and weight. Excluding casing shell parameters led to a lower frequency shift with respect to the reference configuration. The presented optimization framework is very robust and time effective in completing the optimization task together with a sensitivity analysis for the defined design domain. An FEM model validation of the surrogate model showed consistency in the modal analysis results. A promising solution from the component weight standpoint is the optimization with hook position and leaning only. A future research recommendation is to study an extended parameter range to reduce weight impact for this set.

Biomolecules adsorption to trigger the self-assembly of nanospheres and nanorods

HypothesisThe self-assembly (SA) of nanostructures triggered by the adsorption of biomolecules (BSA) is investigated as a platform to develop diagnostics and functional applications. Mixing nanostructures of different morphologies; SiO2 nanospheres (NS) to a cellulose nanorod crystals (CNC) leads to the formation of short range ordered domains in the dried film. Adding biomolecules-treated SiO2 NS into the CNC develop the long range ordered assembly in the composite film. ExperimentsThe CNC-SiO2 composite films were prepared by mixing CNC suspension (3 wt%) with the SiO2 NS of different concentration (0.5–5 mg/mL) followed by drying at the ambient conditions. The CNC-SiO2 @BSA films are prepared by first mixing the BSA (1 mg/mL) with the SiO2 suspension of different concentrations. Later the SiO2 @BSA suspension was mixed with the CNC and left for drying at the ambient conditions. The self-assembly mechanisms of CNC, SiO2 and BSA are studied by combining SEM, DLS, UV-Vis, QCM-D and SAXS analysis. FindingsThe SA mechanism of aqueous suspensions of CNC blended with SiO2 NS pre-treated with BSA (by adsorption) is studied by a combination of small angle X-ray scattering (SAXS), scanning electron microscopy (SEM), UV-Vis spectroscopy (UV-Vis), dynamic light scattering (DLS) and quartz crystal microbalance with dissipation (QCM-D). Both CNC and SiO2 NS are negatively charged and have demonstrated self-assembly ability driven from a combination of long- and short- range order arrangement. Adding SiO2 NS to a CNC suspension disrupts the original SA of both CNC and SiO2, which leads to the formation of small, short- range ordered domains of large polydispersity. Surprisingly, adding BSA-treated SiO2 NS into the CNC network enhances the arrangement of CNC and NS towards a new system with long range ordered assembly. The SA mechanisms of cellulose-SiO2 composites result from the balance of electrostatic repulsion and van der Waal attraction in the structure factor, radial distance distribution and potential of mean force. Understanding the effect of biomolecule adsorption on the self-assembling mechanisms of CNC nanorods with SiO2 nanospheres enables the efficient engineering of catalysis, biosensors and diagnostics.

ATOCA: an Algorithm to Treat Order Contamination. Application to the NIRISS SOSS Mode

After a successful launch, the James Webb Space Telescope is preparing to undertake one of its principal mission objectives, the characterization of the atmospheres of exoplanets. The Single Object Slitless Spectroscopy (SOSS) mode of the Near Infrared Imager and Slitless Spectrograph (NIRISS) is the only observing mode that has been specifically designed for this objective. It features a wide simultaneous spectral range (0.6–2.8 μm) through two spectral diffraction orders. However, due to mechanical constraints, these two orders overlap slightly over a short range, potentially introducing a “contamination” signal in the extracted spectrum. We show that for a typical box extraction, this contaminating signal amounts to 1% or less over the 1.6–2.8 μm range (order 1), and up to 1% over the 0.85–0.95 μm range (order 2). For observations of exoplanet atmospheres (transits, eclipses or phase curves) where only temporal variations in flux matter, the contamination signal typically biases the results by order of 1% of the planetary atmosphere spectral features strength. To address this problem, we developed the Algorithm to Treat Order ContAmination (ATOCA). By constructing a linear model of each pixel on the detector, treating the underlying incident spectrum as a free variable, ATOCA is able to perform a simultaneous extraction of both orders. We show that, given appropriate estimates of the spatial trace profiles, the throughputs, the wavelength solutions, as well as the spectral resolution kernels for each order, it is possible to obtain an extracted spectrum accurate to within 10 ppm over the full spectral range.

XANES spectroscopy for the clinician

XANES spectroscopy, which uses synchrotron radiation as a probe, offers substantial information about the local structure of biological samples, encompassing those without long range order such as Pt anticancer molecules, and nanometre scale or amorphous particles of calcium phosphate. Its subcellular spatial resolution, as well as its capacity to operate at room temperatures and pressures represent major advantages for medical research. Moreover, paraffin embedded biopsy samples can be analysed without any further preparation, Key publications which illustrate these capacities are presented.

Chemical-element-distribution-mediated deformation partitioning and its control mechanical behavior in high-entropy alloys

• Effect of chemical heterogeneities on plasticity and strength is studied using atomic simulations in high-entropy alloys. • Elemental anisotropy/difference factor is proposed, and then used to evaluate the short range order and predict the HEA properties. • Elemental anisotropy factor for optimal high performance is accurately estimated by machine learning. • By a machine learning approach coupled with MD simulations, elemental anisotropy ranges from 2.9 to 3. The chemical element distributions always strongly affect the deformation mechanisms and mechanical properties of alloying materials. However, the detailed atomic origin still remains unknown in high-entropy alloys (HEAs) with a stable random solid solution. Here, considering the effect of elemental fluctuation distribution, the deformation behavior and mechanical response of the widely-studied equimolar random CoCrFeMnNi HEA are investigated by atomic simulations combined with machine learning and micro-pillar compression experiments. The elemental anisotropy factor is proposed, and then used to evaluate the chemical element distribution. The experimental and simulation results show that the local variations of chemical compositions exist and play a critical role in the deformation partitioning and mechanical properties. The high strength and good plasticity of HEAs are obtained via tuning the chemical element distributions, and the optimal elemental anisotropy factor ranges from 2.9 to 3 using machine learning. This trend can be attributed to the cooperative mechanisms depending on the local variational composition: massive partial dislocation multiplication at an initial stage of plastic deformation, and the inhibition of localized shear banding via the nucleation of deformation twinning at a later stage. Using the new insights gained here, it would be possible to create new metallic alloys with superior properties through thermal-mechanical treatment to tailoring the chemical element distribution.

Retainable short-range order effects on the strength and toughness of NbMoTaW refractory high-entropy alloys

Short range order (SRO) can affect the dislocation glide and twin nucleation in high-entropy alloys (HEAs), leading to varying mechanical performance. However, the mechanical implications of SRO in refractory HEAs (RHEAs) remain largely unknown due to the lack of understanding of the nanoscale deformation. Here, the role of SRO on the tensile mechanical properties of single crystal equiatomic NbMoTaW RHEAs is investigated using the hybrid Monte Carlo method and molecular dynamics simulation. We find that the presence of SRO can simultaneously enhance the strength and toughness over a wide range of temperatures under very fast strain rate. The enhancement is larger at lower temperature due to higher degree of SRO. The effects of SRO strengthening and toughening are retainable after unloading from the plastic stage, due to the unexpected twinning-assisted pseudo-elastic deformation. The fundamental principles of SRO are provided to facilitate the rational design and applications of RHEAs.

Supercooled Jahn-Teller ice

When the spins on the frustrated pyrochlore lattice obey the celebrated 2-$in$-2-$out$ ice rule, they stay in a correlated disordered phase and break the third law of thermodynamics. Similarly, if the atomic ions on the pyrochlore lattice move in and outward of the tetrahedra, they may obey a constraint resembling the ice rule. We discover that a model for pyrochlore molybdates $A_2$Mo$_2$O$_7$ ($A=$Y, Dy, Tb) exhibits a "supercooled ice" state of the displacement degrees of freedom of Mo$^{4+}$ ions, when we take account of the Jahn-Teller (JT) effect. The JT effect occurs when the lattice distortions reduce the symmetry of the local crystal field, resulting in the orbital-energy-splitting that causes the local energy gain. Unlike the standard JT effect that leads to periodic long range ordering, the displacements of Mo$^{4+}$ ions are disordered following the ice-like rule. We microscopically derive a model that describes this situation by having the 2nd and 3rd neighbor interactions between in-out lattice displacements comparably as strong as the nearest neighbor interactions of standard ice. There, the well-known nearly flat energy landscape of the ice state is altered to a metastable highly quasi-degenerate ice-like liquid state coexisting with a crystalline-like ground state. Our Monte Carlo simulations show that this liquid remains remarkably stable down to low temperatures by avoiding the putative first order transition. The relaxation in the supercooled JT ice state exhibits glassy dynamics with a plateau structure. They fit the feature of a "good glassformer" very often found in molecular liquids, but that has never been observed in material solids. The high glass-forming ability of the interacting lattice degrees of freedom will play a key role in the spin-glass transition of the material.

Cryogenic thermal cycling rejuvenation in metallic glasses: Structural and mechanical assessment

Rejuvenation in metallic glasses (MGs) can be achieved by means of thermal cycling treatments at cryogenic temperatures. Here, atomic scale studies were carried out to explore thermal cycling in CuZr MGs at different species contents. Enhanced ductility was observed due to several factors. All samples presented higher potential energy and less-dense structures upon treatments, indicating rejuvenated states. Furthermore, populations of high-centrosymmetric Voronoi polyhedra decreased, while liquid-like structures increased, which are usually related to low rigidity. Atomic connectivity was explored as a measure of the medium range order, revealing that thermal cycling reduced the fraction of 3-atom connections, while increased 2-atom and 4-atom connections. Since 3-atom connections are associated to more-ordered structures, its weakening explains the enhanced plasticity achieved by MGs upon thermal cycling treatments. This study provides new insights into rejuvenation of MGs, delivering atomic scale descriptions at both the short range and medium range order.

Intelligent Bi-directional Relaying Communication for Edge Intelligence based Industrial IoT Networks

Within this specific record, our group study the two-way interact body (TWRN) that has a number of amplify-and-forward (AF) relays. In that, the best one is actually really got to help the info communication among sources. A interact option is actually really according to the obsolete channel problem information (CSI) in addition to our group analyze its own very personal effect on the system effectiveness in the Rayleigh fading atmospheres. Especially, we extremely preliminary acquire a restricted decreased connected for the outage opportunity and afterward current an asymptotic assessment for greater signal-to-noise ratio (SNR). Our group extra acquire a restricted decreased connected along with an asymptotic result on the authorize error cost (SER). Originating got via these results, our group easily quickly obtain that body system range order remain at unity offered that the CSI is actually really obsolete. Relative results reveal the rigidness on the effectiveness bounds along with the effects of obsolete interact option on the body system effectiveness. Simulation outcomes are likewise offered to corroborate the scholastic evaluation.

Strontium ferrite SrFeO3-δ (2.50 ≤ 3-δ ≤ 2.87) studied by Raman and Mössbauer spectroscopy

Crystal structure, short range order, lattice dynamics and valence state of polycrystalline single-phase strontium ferrites SrFeO3-δ (with 3–δ = 2.87 ÷ 2.5) were studied by Raman and Mössbauer spectroscopy at normal conditions. Valence states of Fe ions and their fractions were determined from Mössbauer spectroscopy and concentrations of oxygen in all phases were estimated. For all studied SrFeO3-δ phases only five (or less) bands were observed above 200 cm−1 in spite of numerous Raman active phonon modes predicted by a factor group analysis. For the antiferromagnetic Brownmillerite phase (3–δ = 2.5), a broad band observed at ∼ 1350-1400 cm−1, was attributed to the two-magnon scattering. This band was found also for the SrFeO3-δ samples with 3–δ = 2.87 ÷ 2.725 which are in paramagnetic state at room temperature. This fact indicates an existence of the unusual magnetic correlations in all SrFeO3-δ perovskites.

Magnetism in four-layered Aurivillius Bi[formula omitted]FeTi[formula omitted]O15 at high pressures

We report the structural and magnetic properties of four-layer Aurivillius compound Bi5FeTi3O15 (BFTO) at high hydrostatic pressure conditions. The high-pressure x-ray diffraction (XRD) data does not explicitly show structural phase transitions with pressure, however the observed changes in lattice parameters indicate structural modifications at different pressure values. In the initial pressure region values (up to 2.2 GPa), the lattice parameters a- and b- are nearly equal implying a quasi-tetragonal structure, however as the pressure increases a- and b- diverges apart and exhibits complete orthorhombic phase at pressure values of about ≥8 GPa. Principal component analysis (PCA) of high pressure Raman measurements point out an evident change in the local structure at about 5.5 GPa indicating that the evolution of the local structure under applied pressure seems to not follow crystallographic changes (long range order). Nuclear forward scattering (NFS) measurements reveal the development of magnetic ordering in BFTO at 5K with high pressures. A progressive increase in magnetic order is observed with increase in pressure at 5 K. Further, NFS measurements carried out at constant pressure (6.4 GPa) and different temperatures indicate that the developed magnetism disappears at higher temperatures (20 K). It is attempted to explain these observations in terms of the observed structural parameter variation with pressure.

Addressing Opioid Range Order Use in Post Anesthesia Care Units (PACUs) Across a System

<h3>Background Information</h3> Range orders and therapeutic duplication are an ongoing issue in PACUs as we balance the unique needs of our patients with the restrictions of laws and regulatory bodies. At a previous Joint Commission visit, it had been identified there were issues with how range orders were interpreted and applied when treating patient's pain with opioid range orders in PACU Phase I recovery. <h3>Objectives of Project</h3> Identify and implement a tool to assist in standardization of PACU Phase I clinician interpretation and use of IV opioid range orders. <h3>Process of Implementation</h3> Multidisciplinary team convened to create the PACU/Recovery Room Opioid Order Management – Adult tool. Clinicians completed an in-depth Computer Based Training with a case study focus to become familiar with utilizing the tool with different patient scenarios encountered every day in the PACU. <h3>Statement of Successful Practice</h3> Chart reviews demonstrate consistency between clinicians with regard to dosing titration increments defined by the tool. The tool meets hospital policy requirements. During the most recent Joint Commission site survey, when a clinician was asked how range orders were utilized, the clinician was able to speak in detail to the tool and how IV opioid range orders are utilized in the PACU phase of care to treat pain. In the closing meeting with the Joint Commission surveyor, the tool was identified as a leading practice. <h3>Implications for Advancing the Practice of Perianesthesia Nursing</h3> The PACU/Recovery Room Opioid Management Tool supports standardization of initial and consecutive doses of range ordered opioids, allowing nurses to continue to manage a patient's individual pain management needs with the flexibility range orders offer.

Proper condensates and long range order

Within the framework of the algebra of canonical commutation relations in position space, a long range order between particles in bounded regions is established in states with a sufficiently large particle number. It occurs whenever homogeneous proper (infinite) condensates form locally in the states in the limit of infinite densities. The condensates are described by eigenstates of the momentum operator, covering also those cases where they are streaming with a constant velocity. The arguments given are model independent and lead to a new criterion for the occurrence of condensates. It makes use of a novel approach to the identification of condensates, based on a characterization of regular and singular wave functions.

A Quantitative Understanding of the Short Range Order in Disordered Rocksalt Cathode Materials

A Quantitative Understanding of the Short Range Order in Disordered Rocksalt Cathode Materials

Structural and optical characterization of semiconducting lithium modified zinc borate glassy system for UV band reject filter

The amalgamation of different compositions of 20ZnO.(80-x)B2O3.xLi2O (x = 10, 20, 30 and 40) glasses have been performed via well-known melt quenching technique. The absence of any sharp peak in X-ray Diffractograms confirms short range order i.e. amorphous nature of selected glass series. Calculations of density (ρ) have been done using the Archimedes principle and further different physical parameters such as molar volume (Vm), crystalline volume (Vc), bond density (nb), electronegativity difference (∆x), bond ionicity (Ib), boron-boron distance (<dB-B>), polaron radius (Rp), lithium ion concentration (N), lithium interionic separation (Ri), and lithium yield field strength (F) were calculated and found to be in correlation. Structural modifications occurring in the glass network with the addition of lithium oxide have been studied by identifying and careful assignment of structural groups present in the IR and Raman spectra on the basis of literature survey. The FTIR and Raman analysis revealed that the neutral triangular structural units (BØ3) transforms into charged tetrahedral borate units (BØ4−) which signifies the compactness of the glass network with enhancement in lithium concentration. The optical transmission studies revealed that glass composition 20ZnO.40B2O3.40Li2O acts as a UV band reject filter for wavelengths ranging from (247-323)nm whereas it acts as a transparent window with ∼80% transparency in the visible region. These optical features make glass composition 20ZnO.40B2O3.40Li2O suitable for radiation protection shields and may be used as an UV protective coating on window/sun glasses. The optical absorption spectrum has been in the light of the Mott and Davis model, Hydrogenic Excitonic model and modified Urbach energy model for extracting different optical parameters.

Gd(OH)F2: A Promising Cryogenic Magnetic Refrigerant.

Magnetic refrigerants with a large magnetocaloric effect (MCE) in a wide temperature range and low magnetic ordering temperature (To) in the sub-kelvin temperature region are not only crucial for adiabatic demagnetization refrigeration but also open up a broader parameter space for the optimal design of adiabatic demagnetization refrigerators. However, such magnetic refrigerants are extremely rare because they require magnetic materials to simultaneously satisfy three conditions: low To, weak magnetic interaction, and high magnetic density. Here, we report the syntheses, heat capacities, and magnetic properties of Gd(OH)3-xFx (1: x = 1, 2: x ≈ 1.5, and 3: x = 2), demonstrating for the first time that the introduction of fluoride anions into antiferromagnetic Gd(OH)3 can effectively regulate its To. Significantly, 3 not only has a To of 0.5 K but also exhibits a large MCE in the temperature range from 0.5 to 4 K, representing the best magnetic refrigerant reported to date in the temperature range of 0.5-4 K from the viewpoint of the MCE.

Modelling Intensity Fluctuations of Rayleigh Backscattered Coherent Light in Single-Mode Fibers

This work reportsa thorough analysis of intensity fluctuations of Rayleigh backscattered coherent light in single mode optical fibers. Based on the intermediate range order of silica glasses and on residual stress of optical fibers, a theoretical model was built to calculate intensity fluctuations of Rayleigh backscattered coherent light in the optical frequency domain. Numerical simulation results were compared to experimental results in time domain, strongly supporting the conclusion that Rayleigh backscattering in single mode fibers is an ergodic process exhibiting ergodicity in the time-frequency sense so that the model can be used to determine the statistical behavior of backscattered intensity fading.

Intercalant-mediated Kitaev exchange in Ag3LiIr2O6

The recently synthesized ${\mathrm{Ag}}_{3}{\mathrm{LiIr}}_{2}{\mathrm{O}}_{6}$ has been proposed as a Kitaev magnet in proximity to the quantum spin liquid phase. We explore its microscopic Hamiltonian and magnetic ground state using many-body quantum chemistry methods and exact diagonalization techniques. Our calculations establish a dominant bond dependent ferromagnetic Kitaev exchange between Ir sites and find that the inclusion of Ag $4d$ orbitals in the configuration interaction calculations strikingly enhances the Kitaev exchange. Furthermore, using exact diagonalization of the nearest-neighbor fully anisotropic $J\text{\ensuremath{-}}K\text{\ensuremath{-}}\mathrm{\ensuremath{\Gamma}}$ Hamiltonian, we obtain the magnetic phase diagram as a function of further neighbor couplings. We find that the antiferromagnetic off-diagonal coupling stabilizes long range order, but the structure factor calculations suggest that the material is very close to the quantum spin liquid phase and the ordered state can easily collapse into a liquid by small perturbations such as structural distortion or bond disorder.