Inelastic Components Research Articles

Conceptual study of a new instrument for dynamic neutron scattering measurements-The modulated intensity with diffraction analysis spectrometer (MIDAS).

Dynamic neutron scattering probes unique nanoscale dynamics via measurement of energy exchanged between a sample and the neutrons. The two spectrometers that investigate processes with characteristic times around a nanosecond are backscattering (BS) and neutron spin-echo (NSE). We present a new method for measuring dynamics using an oscillating cosine-like energy-distribution neutron-package at the sample and measure solely the portion scattered into the elastic line. This portion corresponds to elastically scattered neutrons and, in addition, inelastic components that are scattered with a probability directly proportional to the cosine Fourier-coefficients of the exchanged-energy spectrum. The counts at the detector thus correspond to the van Hove intermediate scattering function. We denote this new method as "Fourier transform neutron scattering" (FTNS), it being broadly analogous to IR and Raman spectroscopies. Here, the realization of such a concept is investigated using an oscillating incident beam produced via a precession method and a secondary spectrometer identical to a BS instrument using crystal analyzers. The instrument is denoted "Modulated Intensity with Diffraction Analysis Spectrometer" (MIDAS). However, simpler approaches, e.g., choppers, may also be used for an FTNS instrument. The theory behind MIDAS is presented, supported by numerical calculations and in silico experiments. Finally, we present a Monte Carlo simulation to compare BS and MIDAS spectrometers. This shows that MIDAS has almost 100 times more incident flux than standard BS, but due to the better signal-to-noise ratio of BS, the final information acquisition rate gain of MIDAS is approximately a factor of 2.

Transport and Nonreciprocity in Monitored Quantum Devices: An Exact Study.

We study noninteracting fermionic systems undergoing continuous monitoring and driven by biased reservoirs. Averaging over the measurement outcomes, we derive exact formulas for the particle and heat flows in the system. We show that these currents feature competing elastic and inelastic components, which depend nontrivially on the monitoring strength γ. We highlight that monitor-induced inelastic processes lead to nonreciprocal currents, allowing one to extract work from measurements without active feedback control. We illustrate our formalism with two distinct monitoring schemes providing measurement-induced power or cooling. Optimal performances are found for values of the monitoring strength γ, which are hard to address with perturbative approaches.

Acoustic monitoring humidity effects on the formation of water bridges at sharp contacts

Shear-force Acoustic Near-field Microscopy (SANM) and Whispering Gallery Acoustic Sensing (WGAS) are used to evaluate the role of humidity on the formation and rupture of water meniscus bridges that form between a laterally oscillating tapered probe and a flat substrate. SANM monitors the near-field acoustic wave emitted by the meniscus, while WGAS monitors acoustically the probe’s amplitude of oscillation, as a function of the probe-sample distance. In the instances reported here, the SANM/WGAS measurements are performed in frequency modulation modality, which allows to discriminate the elastic and inelastic components of the probe-fluid-substrate interaction. The response signal traces, acquired when the probe first approaches and then retracts from the sample at 56% relative humidity (or below), revealed absence of hysteresis; this result persists when performing the same experiment a few days later. However, as the humidity increases (different trials from 56% to 67% are included) a notorious hysteresis is observed between the approach and retraction traces. The results indicate that, as the probe approaches the substrate, a higher humidity promotes an increase of stochastic instabilities in the probe-fluid-substrate interactions (reflected in higher damping effects on the probe, and instabilities in the probe-sample distance feedback control). However, the elastic response of the water meniscus prevails over damping effect, as revealed by the greater acoustic emission despite a decrease in the probe’s amplitude. These measurements are relevant to investigations on the dynamic behavior of fluids near hydrophobic/philic substrates, and wetting properties of solids and nanotribology phenomena in general.

Peierls plasticity of thermoelectric lead telluride assessed by local misfit energy

High brittleness observed in p-type PbTe is a significant obstacle in the commercial use of PbTe-based thermoelectric materials. An in-depth study of dislocations in PbTe is crucial due to their significant impact on material plasticity. In this work, the properties of 12[011](0 1¯ 1) edge dislocation in PbTe are investigated by using the local misfit energy of a shear model within the framework of the Peierls–Nabarro theory. By incorporating a moderate strain region size, a smooth and gradual transition of Pb–Te bonds during the shear process can be facilitated while balancing the elastic and inelastic components of the local misfit energy. The average misfit energy and the Peierls stress of the dislocation are calculated and compared with those of SrTiO3, a material that has demonstrated unexpected plasticity in its single crystal form. The findings indicate that undoped PbTe exhibits reasonably good plasticity. This work presents a theoretical approach to investigate dislocation properties in PbTe, laying the foundation for further research on the mechanical aspects of p-type dopant-induced issues in PbTe-based materials.

Collective modes in molten CsCl, CuCl and AgI observed by inelastic x-ray scattering

Inelastic x-ray scattering measurements have been carried out for molten CuCl and AgI and the results were compared with those in molten CsCl by Inui et al. (2007) [42]. The inelastic components arising from collective excitation were observed on both sides of the quasielastic component at the center in the dynamic structure factor. As a result of examining several model functions to fit the observed dynamic structure factor with convolution of the spectrometer resolution function, we adopted the conventional damped harmonic oscillator with a Lorentzian for the quasielastic component. From the apparent sound speed and the linewidth of the collective excitation, the ionic dynamics of molten AgI was found to be different from that in molten CsCl and CuCl, suggesting that AgI has the strongest covalent bonding nature among these molten salts. Meanwhile the relaxation times estimated from the width of the quasielastic components indicated that ionic dynamics in noble metal halides differs from that in molten CsCl.

The contribution of Compton ionization to ultrafast x-ray scattering.

We investigate the role of Compton ionization in ultrafast non-resonant x-ray scattering using a molecular model system, which includes the ionization continuum via an orthonormalized plane wave ansatz. Elastic and inelastic components of the scattering signal, as well as coherent-mixed scattering that arises from electron dynamics, are calculated. By virtue of a near-quantitative distinction between scattering related to electronic transitions into bound and continuum states, we demonstrate how Compton ionization contributes to the coherent-mixed component. Analogous to inelastic scattering, the contribution to the coherent-mixed signal is significant and particularly manifests at intermediate and high-momentum transfers. Strikingly, for molecules with inversion symmetry, the exclusion of bound or continuum transitions may lead to the prediction of spurious coherent-mixed signals. We conclude that qualitative and quantitative accuracies of predicted scattering signals on detectors without energy resolution require that elements of the two-electron density operator are used. This approach inherently accounts for all accessible electronic transitions, including ionization.

Carbon Elastic and Inelastic Stopping-Power Components for Heavy Ions at Bohr and Higher Velocities

Carbon stopping power (SP) data for heavy ions (HIs), obtained around Bohr velocities, revealed remarkably lower values than those predicted using the SRIM/TRIM calculations/simulations. An attempt was made to extract the elastic (collisional) and inelastic (electronic) components from the available SP data obtained in experiments. A problem is that essentially, total SP is measured in experiments, whereas electronic SP values, usually presented as the results, are derived via the subtraction of the calculated collisional component from the measured values. At high HI reduced velocities (V/v0)/ZHI2/3≳0.3 (V and v0 are HI and Bohr velocities, respectively, and ZHI is the HI atomic number), the collisional component can be neglected, whereas at Bohr velocities it becomes comparable to the electronic one. These circumstances were used to compare the experimental SP data with the SRIM/TRIM calculations/simulations and to empirically obtain corrections to the collisional and inelastic SP components.

Quantifying seasonal ground deformation in Taiyuan basin, China, by Sentinel-1 InSAR time series analysis

The presence of seasonal surface deformation in areas that are subsiding/uplifting due to groundwater pumping/recovery can indicate aquifer recharge. Understanding seasonal surface deformation and the existing relationship between triggering factors and the deformation supports effective groundwater management and subsidence mitigation. Here, we investigated seasonal ground displacement in response to the aquifer compaction and expansion due to groundwater extraction and recharge within the Taiyuan basin, Northern China. We obtained Sentinel-1 InSAR displacement time series data from 2017 to 2020 and quantitatively analyzed relationships between triggering factors (e.g., groundwater level and precipitation) and the associated displacements using wavelet-based methods. The results show that the seasonal deformation is concentrated in the irrigated areas within the central basin, with a 1-year periodicity. The annual peak-to-peak amplitude was up to 2 cm, peaking in March with troughs in August. This seasonality present in the displacement time series is found to be ‘in-phase’ with respect to groundwater levels and ‘anti-phase’ in relation to natural precipitation. These results are consistent with the irrigation pumping practices in the basin, with increased groundwater withdrawals to meet irrigation water demand prior to the monsoon precipitation season, resulting in water level decline and land subsidence from mid-March to mid-August. During the non-irrigated season, groundwater extraction decreases, and the aquifer systems are replenished by precipitation, causing water levels to recover and the ground to uplift from late August to mid-March. A geological analysis indicates that the seasonal deformation is controlled by the thickness of Quaternary strata and fault systems, which play a critical role in forming the earth fissures in the basin. The elastic and inelastic deformation was separated; the estimated elastic/inelastic ratio was about 0.6–0.7, indicating that the inelastic component dominates the main aquifer compaction in the central basin. Our analysis is of hydrologic importance which could be used to guide groundwater management and subsidence mitigation, given the inter-basin water diversion projects in this arid basin.

Some features of flat fiberglass specimens’ behavior under three-point bending

The authors carried out the experimental works devoted to the problem of describing the processes occurring under long-term loading of composite materials. They studied a glass-reinforced plastic (GP) flat specimen under three-point bending and assumed the deformations normal to the section are purely elastic, and the transverse shear deformation consists of two parts –elastic, and creep deformations and damages formed as a result of accumulation. The authors considered a variant of the creep ratios according to the hardening theory. In previous research authors determined its parameters based on the analysis of the tubular samples operation. It was found that even for thin beams, in contrast to a purely elastic problem, taking into account creep under transverse shear leads to inelastic deflection components that are comparable with their elastic values. The authors presented the results of numerical calculations. It is concluded that at large time and loads, deformations appear in the sample caused by the accumulation of damage.

A novel methodology for characterizing fracture process zone evolution in Barre granite specimens under mode I loading

Fracturing in quasi-brittle such as rock involves the development of an inelastic zone around the pre-crack tip, also known as the fracture process zone (FPZ). The evolution of FPZ, while influencing the fracture behavior of rocks, is difficult to characterize due to the localized nature of material behavior and microstructural heterogeneities. This study presents a digital image correlation technique (DIC)-based method that consistently describes the FPZ evolution in mode I fracture of Barre granite specimens. The FPZ characteristics were also evaluated using acoustic emission (AE) monitoring. The evolution of the crack tip opening displacement (CTOD) was analyzed to estimate the various fracture parameters, such as threshold values of the elastic and critical opening displacements and the size of the fully developed FPZ. The comparison of DIC-based measurements with the AE-based microcracking activities demonstrated that the displacement approach of the former could be used independently to identify the transition among the three stages of FPZ evolution, namely, (1) elastic stage, (2) formation of FPZ, and (3) macro-crack initiation. Experimental results also indicate a linear relationship between the FPZ length and the inelastic component of the CTOD, along with the quadratic relationship between the local dissipated energy and the FPZ length, which is consistent with the linear softening law for material inside the FPZ.

Systematic study of Δ (1232) resonance excitations using single isobaric charge-exchange reactions induced by medium-mass projectiles of Sn

The fragment separator FRS has been for the first time used to measure the (n,p) and (p,n)-type isobaric charge-exchange cross sections of stable 112,124Sn isotopes accelerated at 1A GeV with an uncertainty of 3% and to separate quasi-elastic and inelastic components in the missing-energy spectra of the ejectiles. The inelastic contribution can be associated to the excitation of isobar {\Delta}(1232) resonances and to the pion emission in s-wave, both in the target and projectile nuclei, while the quasi-elastic contribution is associated to the nuclear spin-isospin response of nucleon-hole excitations. The data lead to interesting results where we observe a clear quenching of the quasi-elastic component and their comparisons to theoretical calculations demonstrate that the baryonic resonances can be excited in the target and projectile nuclei. To go further in this investigation, we propose to study the excitation of baryonic resonances taking advantage of the combination of high-resolving power magnetic spectrometers with the WASA calorimeter. These new measurements will allow us to determine the momenta of the ejectiles and pions emitted in coincidence after the single isobaric charge-exchange collisions, providing us unique opportunities to study the evolution of the baryonic resonance dynamics with the neutron-proton asymmetry through the use of exotic radioactive ion beams.

Higher mode effects on capacity curves

The effects of higher modes on the capacity curves and their effects on the formation of plastic hinges are studied herein for regular reinforced concrete structure with no any weak or soft story having time period typically less than 1 sec. The theoretical validity of modal pushover analysis is explained with respect to elastic and inelastic systems. In this modal pushover analysis (MPA), the seismic demand due to individual terms in the modal expansion of the effective earthquake forces is determined by a pushover analysis using the inertia force distribution for each mode. The higher mode pushover curves show significant increase in base shear as well as significant decrease in roof displacement that are not detected by the first mode which is a part of FEMA-356 force distributions. To determine the difference of seismic response parameter at concerned point, local performance levels are used rather than global performance level for better accuracy. Fiber plastic hinges model is used instead of conventional lumped plastic hinge where stress-strain curves is directly applied for confined concrete to inner core concrete and unconfined stress- strain to outer concrete. Base Shear of Capacity Curve at IO performance level, inelastic beam component with compressive stress at 0.002 and 0.0038 increased by 14.52 %, 10.825 %, and 10.42 % respectively. Displacement Demand of Capacity Curve at IO performance level, inelastic beam component with compressive stress at 0.002 and 0.0038 decreased by 15.84 %, 15. 94 % and 12.86 %. It is seen that up to 3rd mode is crucial and should be amalgamate in regular structure and up to 8th mode should be amalgamate in irregular structure

A dual pressure indicator, two-layer compression system for treatment of venous leg ulcers: a review.

Venous leg ulcers (VLUs) are considered the most frequent category of hard-to-heal limb ulcers. Although evidence-based care of VLUs suggests that compression therapy plays a pivotal role in the standard of care, patient adherence is considered low, with at least 33% non-compliance, either due to perceived problems from clinicians regarding their own competency in applying the bandages, or from the patient finding the wrapping bothersome. For many years, four-layer bandaging has been considered the 'gold standard', but application can be difficult and may also prove uncomfortable for patients. Accurate application may be facilitated by a stretch indicator which has been engineered to act as a surrogate for appropriate pressure application that can address the skill concern, while fewer layers can save clinicians' time and improve the quality of life of patients. Here, we review the literature supporting a two-layer system which combines elastic (long stretch) and inelastic (short stretch) components as well as both layers having graphic markers to define that the dressing has been applied at the proper tension. An initial search was conducted on PubMed and then followed up by a manual search of Google Scholar to retrieve evidence of different levels, in order to evaluate the outcomes of use of the specific two-layer compression system with pressure indicators in the management of patients presenting with VLUs. A total of four papers discussing the specific compression system in question were identified from 32 publications retrieved from PubMed, while a further six were retrieved from Google Scholar. These 10 publications were considered relevant to the two-layer system and were analysed for the outcomes of care, including wound healing, appropriate application, time-saving and better patient acceptance and adherence. Previous authors have demonstrated that two-layer systems are equivalent to four-layer systems. However, the ability to reproducibly apply appropriate compression has remained a question. The papers reviewed demonstrate that evidence suggests that the two-layer compression bandage system with indicators provides continuous, consistent and comfortable treatment that may be easier to apply with accurate pressure levels due to their indicator systems, and therefore, is a procedure that may increase patient adherence and acceptability to the wound therapy.

Polar inelastic profiles in fast-atom diffraction at surfaces

Elastic diffraction of fast atoms at crystal surfaces under grazing incidence $\ensuremath{\theta}\ensuremath{\approx}1$\ifmmode^\circ\else\textdegree\fi{} has strong similarities with atomic diffraction at thermal energies discovered almost hundred years ago. Here, we focus on the polar scattering profile, which does not exhibit diffraction features but shows well-defined elastic and inelastic components that are found to be essentially independent of the crystallographic axis. The width ${\ensuremath{\sigma}}_{\ensuremath{\theta}}$ of the inelastic component is very sensitive to the weak attractive forces responsible for the physisorption. This effect is visible on an energy range almost ten times larger than the depth $D$ of the physisorption well. Experimental data are analyzed using a binary collision model with a Morse potential where the width ${\ensuremath{\sigma}}_{\ensuremath{\theta}}$ of the scattering profile is connected to the classical energy loss and is governed by the surface stiffness, defined as the logarithmic derivative of the interaction potential along the surface normal. The main outcome is that the weak attractive forces make the mean surface potential almost twice harder at low energy.

Modelling nonlinear behavior of [formula omitted] frames using the Force Analogy Method

The nonlinear dynamic analysis of civil engineering structures is a topic of high significance for civil engineering community. In recent years, the linear dynamic analysis, in which no damage is taken into account, was improved to consider various sources of nonlinearity. Many commercial software packages were developed to consider both the material and geometrical nonlinearity. A new technique, entitled the Force Analogy Method, was introduced recently. In this technique, the material nonlinearity is addressed by considering a constant stiffness matrix throughout the entire dynamic analysis. Based on the principle of superposition, the displacement vector is decomposed into an elastic and inelastic component. The inelastic component of the displacement will cause perturbation forces once this term is moved to the right hand side of the equation of motion. However, although this intriguing technique has proved to be both accurate and numerical efficient over the years, no paper has addressed the 3D models case yet. In this paper, the authors develop the fundamental approach to generalize FAM for modeling the nonlinear response of three dimensional frame structures. The numerical results obtained are compared and validated using a well established commercial software.

Separation of the inelastic and elastic scattering in time-of-flight mode on the pinhole small-angle neutron scattering diffractometer K-WS-2.

To study and control the incoherent inelastic background in small-angle neutron scattering, which makes a significant contribution to the detected scattering from hydrocarbon systems, the KWS-2 small-angle neutron scattering diffractometer operated by the Jülich Centre for Neutron Science (JCNS) at Heinz-Maier Leibnitz Zentrum (MLZ), Garching, Germany, was equipped with a secondary single-disc chopper that is placed in front of the sample stage. This makes it possible to record in time-of-flight mode the scattered neutrons in the high-Q regime of the instrument (i.e. short incoming wavelengths and detection distances) and to discard the inelastic component from the measured data. Examples of measurements on different materials routinely used as standard samples, sample containers and solvents in the experiments at KWS-2 are presented. When only the elastic region of the spectrum is used in the data-reduction procedure, a decrease of up to two times in the incoherent background of the experimentally measured scattering cross section may be obtained. The proof of principle is demonstrated on a solution of bovine serum albumin in D2O.

Isobaric charge-exchange reactions: a tool to study the excitation of baryonic resonances in exotic nuclear matter

Isobaric charge-exchange reactions induced by beams of 112Sn have been investigated at the GSI facility using the fragment separator FRS. The high-resolving power of this spectrometer makes it possible to obtain the isobaric charge-exchange cross sections with an uncertainty of 3.5% and to separate quasi-elastic and inelastic contributions in the missing-energy spectra, in which the inelastic component is associated to the in-medium excitation of baryonic resonances such as the Δ resonance. We report on the results obtained for the (p,n) channel excited by using different targets that cover a large range in neutron excess. In addition, we also compare the missing-energy spectra with an intranuclear cascade model coupled to a de-excitation code to investigate the in-medium effects in the production of baryonic resonances.

Multidetector Pulsed-Neutron Tool Application in Low-Porosity Reservoir–A Case Study in Mutiara Field, Indonesia

In mature fields, pulsed-neutron logging is commonly used to solve for the remaining saturation behind the casing. For years, sigma-based saturation has been used to calculate gas saturation behind casing; however, the high dependency of sigma-to-water salinity of the formation, especially the low-dynamic range at porosity near 12 p.u., has proven to be challenging in low-porosity gas rock. A new measurement from the third detector from a multidetector pulsed-neutron tool (MDPNT) is proposed to provide a better estimation of the gas saturation in a low-porosity reservoir. Two sets of independently measured sigma and the third detector were taken in a casedhole well, with a dual-tubing system of a long string and short string. For the third-detector measurement, the measurement was based on the ratio of the slow capture gate and inelastic gate component from the decay curve created by the long detector. This ratio can be used to detect gas in a tight reservoir with a minimum salinity and lithology effect. This data will then be used to calculate the gas saturation from the third detector, and the result is compared to sigma-based gas saturation. At an interval where the porosity is above 12 p.u., the sigma-based gas saturation and MDPNT-based gas saturation are very much in agreement. However, in a low-porosity reservoir near 12 p.u. or below, the sigma-based measurement starts to show its limitation. Meanwhile, the MDPNT-based gas saturation clearly shows the remaining gas saturation where sigma-based measurements failed to detect it. The subsequent decision was made based on the log analysis result, and perforation was done at a potential interval based on the MDPNT result. The results from the production test confirm the MDPNT-based gas saturation with 700-Mscf/d gas production added. This study showcases a new technology to solve a low-porosity gas reservoir issue where a sigma-based measurement underestimates the remaining gas saturation. Using two different measurements in the same well, the results from the MDPNT measurement demonstrated a better result compared to the sigma-based measurement in low-porosity rock

Excitation of baryonic resonances in stable medium-mass nuclei of Sn

Isobaric charge-exchange reactions induced by beams of 112Sn have been investigated at the GSI facilities using the fragment separator FRS. The high-resolving power of this spectrometer makes it possible to obtain the isobaric charge-exchange cross sections with an accuracy of 3% and to separate quasi-elastic and inelastic contributions in the missing-energy spectra, in which the inelastic component is associated to the in-medium excitation of baryonic resonances such as the Δ resonance. We report on the results obtained for the (p,n) and (n,p) channels excited by using different targets that cover a large range in neutron excess.

Study of Δ excitations in medium-mass nuclei with peripheral heavy ion charge-exchange reactions

Isobaric single charge-exchange reactions, changing nuclear charges by one unit but leaving the mass partitions unaffected, have been for the first time investigated by peripheral collisions of 112Sn ions accelerated up to 1A GeV at the GSI facilities. The high-resolving power of the FRS spectrometer allows us to obtain (p,n)-type isobaric charge-exchange cross sections with an uncertainty of 3.5% and to separate quasi-elastic and inelastic components in the missing-energy spectra of the ejectiles. The inelastic component is associated to the excitation of the Δ(1232) isobar resonance and the emission of pions in s-wave both in the target and projectile nucleus, while the quasi-elastic contribution is associated to the nuclear spin-isospin response of nucleon-hole excitations. An apparent shift of the Δ-resonance peak of ∼63 MeV is observed when comparing the missing-energy spectra obtained from the measurements with proton and carbon targets. A detailed analysis, performed with a theoretical model for the reactions, indicates that this observation can be simply interpreted as a change in the relative magnitude between the contribution of the excitation of the resonance in the target and in the projectile.