Magnitude Of Relaxation Research Articles

Improved data analysis for molecular dynamics in liquid CCl4

Previously reported inelastic x-ray scattering spectra of a typical van der Waals molecular liquid CCl4 were reanalyzed using a generalized Langevin formalism with a memory function including a thermal and two viscoelastic relaxation processes and simple sparse modeling. The obtained excitations of longitudinal acoustic phonons show a largely positive deviation from the hydrodynamic value by about 57%, much larger than about 37% by the previously reported damped harmonic oscillator result. Such large values of fast sounds in molecular liquids larger than 15-20% of typical liquid metals are interpreted as extra energy losses for terahertz phonons by molecules' vibrational and rotational motions. The rates of the fast and slow viscoelastic relaxations in the memory function at low Q indicate large values, about 0.5 and 2 ps, which correspond to the vibrational and rotational motions of CCl4 molecules, respectively. These values are larger than those of the typical polar molecular liquid acetone, which may reflect the heavier atomic mass of CCl4. The Q dependences of the viscoelastic relaxation rates are discussed in terms of the lifetime and propagating length of the terahertz phonon oscillations. The microscopic kinematic longitudinal viscosity was obtained from the viscoelastic relaxation magnitudes and times, rapidly decreasing with Q from a macroscopic value at Q→0.

Abstract 12220: Intracavitary Left Ventricular Flow During Isovolumic Relaxation: Prevalence, Mechanism and Clinical Outcomes

Introduction: Intracavitary flow (IVF) from LV base to apex during isovolumic relaxation (IVR) has been identified in patients with Grade I diastolic dysfunction (G1DD) associated with impaired relaxation. We examined the prevalence, mechanism, and outcomes of this phenomenon. Methods: Echocardiograms and medical records of 113 patients who met ASE criteria for G1DD without other cardiac abnormalities were reviewed. IVR was from relaxation onset to mitral opening. IVF was an apically directed signal with a defined envelope recorded by CW Doppler during IVR (Figure) confirmed by color Doppler. Global longitudinal strain was obtained in standard fashion using commercial equipment and analyzed for apical and basal segments. Results: IVF during IVR was present in 35 patients, absent in 27, and had inconclusive signals not meeting criteria in 51. The magnitude of reduction in apical strain was significantly larger in IVF patients than those without (-14% vs -5%, p = 0.04). This difference was present in both the lateral (-18% vs -7%, p = 0.04) and septal (-11% vs -1%, p = 0.05) segments. The rate of reduction in apical strain was also higher in the IVF group (0.318 strain fractions/sec vs 0.168, p = 0.03). No significant differences between groups existed for proportion of apical relaxation, change in strain between apex/base, proportion/magnitude/rate in basal strain. Patients with IVF during IVR had a non-significant trend for a higher death rate (23 vs 11%). There was no significant difference in hospitalization, heart failure, atrial fibrillation, CAD, or stroke. Conclusions: Apical intracavitary flow during IVR occurred in 31% of G1DD patients. Although mechanism is not fully defined, our data indicates that IVF during IVR is related to the magnitude and rate of apical relaxation. IVF during IVR may be of value in stratifying future risk in Grade I diastolic dysfunction patients but will require larger studies.

The Role of Clay in Limiting Frictional Healing in Fault Gouges

AbstractFrictional healing is fundamental to the seismic cycle and plays a role in the energy balance, dynamics, and recurrence interval of earthquakes and slow slip events. Although the healing behavior of quartz has been studied extensively, the role of clay content is less understood. We tested synthetic mixtures of quartz and smectite (10%–100% smectite) in a double‐direct shear configuration to measure frictional healing. We show that the magnitude and rate of healing decreases systematically with higher clay content (from 0.008/decade at 10% smectite to 0.002/decade at 100% smectite). Healing scales with both the magnitude of stress relaxation during holds and layer‐normal compaction of the gouge. We suggest this reflects the alignment of clay minerals, leading to saturation of the real area of contact that limits restrengthening during holds. The low healing rates of clay‐rich faults—together with rate‐neutral to rate‐strengthening friction—should promote frequent, small failures or stable sliding.

Shear resistance relaxation of granular materials under vibration and restricted deforming conditions

The phenomenon of vibration-induced shear resistance relaxation (ViSRR) refers to the loss of shear resistance in granular materials subjected to vibration, without an observable increase of excess pore pressure, under restricted deforming conditions. Essentially, ViSRR occurs when the total deformation of granular materials is unable to keep up with the plastic deformation induced by the vibration, given the restricted deforming conditions. In this study, ViSRR is investigated through a series of specially designed experiments together with theoretical simulation based on the extended shear transformation zone (STZ) model developed for granular materials. The results demonstrate that ViSRR takes place in granular materials under monotonic shearing when the vibration is superimposed, and the magnitude of shear resistance relaxation depends on the intensity of the vibration. The occurrence of ViSRR is subject to two fundamental prerequisites: superimposed vibration as the driving force for plastic deformation, and restricted total deformation that impedes a granular material's deformability to follow the development of plastic deformation. The simulation results obtained from the extended STZ model are in agreement with laboratory test results, indicating that the model is effective in describing the process of shear resistance relaxation and the accompanying volumetric strain during vibration.

Small crater relaxation and ice abundance at high northern latitudes on Mars

The cold, northern high-latitudes around the Phoenix landing site feature a population of small and very shallow craters known as palimpsest craters or boulder halos that could give insight into the subsurface ice content of the region. Notably there is also a split in the population by the size of craters that feature blocky ejecta: the smallest crater sizes that are <200–350 m in diameter typically do not feature blocky ejecta, while craters larger than this size range do. This has been interpreted as there being a less consolidated layer of mainly ice that sits over a more consolidated layer containing more silicate material from which the larger craters are able to excavate the blocky ejecta. This work focuses on determining whether these 200 m - 1 km shallow craters could be indicative of topographic relaxation due to substantial ice in the subsurface, with goals to determine the subsurface structure and most importantly the amount of ice present through its abundance and depth extent. We use finite element modeling of axisymmetric simple craters, employing the most recent characterizations of solid-state creep for water ice, silicate-rich ice, and CO2 ice, to determine the timescales and magnitudes of relaxation accommodated by an icy single or multiple material layered subsurface to determine the environment's properties. Our models include a 35 m thick layer of pure ice (water, or water and CO2) over a mobile substrate of particulate rich water ice of variable thicknesses able to accommodate relaxation for larger crater sizes up to 1 km in diameter. Our findings demonstrate that relaxation is able to account for significant flattening of crater topography, though for smaller craters the relaxation is incomplete, leaving about half the depth. The accommodated relaxation of our modeled subsurface does imply associated increases in ice abundances of 4 to 10 times greater than is currently estimated for the region, dependent on the extent of the mobile layer.

Systematic Trends in Hybrid-DFT Computations of BaTiO3/SrTiO3, PbTiO3/SrTiO3 and PbZrO3/SrZrO3 (001) Hetero Structures

We performed predictive hybrid-DFT computations for PbTiO3, BaTiO3, SrTiO3, PbZrO3 and SrZrO3 (001) surfaces, as well as their BaTiO3/SrTiO3, PbTiO3/SrTiO3 and PbZrO3/SrZrO3 (001) heterostructures. According to our hybrid-DFT computations for BO2 and AO-terminated ABO3 solid (001) surfaces, in most cases, the upper layer ions relax inwards, whereas the second layer ions shift upwards. Our hybrid-DFT computed surface rumpling s for the BO2-terminated ABO3 perovskite (001) surfaces almost always is positive and is in a fair agreement with the available LEED and RHEED experiments. Computed B-O atom chemical bond population values in the ABO3 perovskite bulk are enhanced on its BO2-terminated (001) surfaces. Computed surface energies for BO2 and AO-terminated ABO3 perovskite (001) surfaces are comparable; thus, both (001) surface terminations may co-exist. Our computed ABO3 perovskite bulk Γ-Γ band gaps are in fair agreement with available experimental data. BO2 and AO-terminated (001) surface Γ-Γ band gaps are always reduced with regard to the respective bulk band gaps. For our computed BTO/STO and PTO/STO (001) interfaces, the average augmented upper-layer atom relaxation magnitudes increased by the number of augmented BTO or PTO (001) layers and always were stronger for TiO2-terminated than for BaO or PbO-terminated upper layers. Our B3PW concluded that BTO/STO, as well as SZO/PZO (001) interface Γ-Γ band gaps, very strongly depends on the upper augmented layer BO2 or AO-termination but considerably less so on the number of augmented (001) layers.

Characteristics of Open Circuit Voltage Relaxation in Lithium-Ion Batteries for the Purpose of State of Charge and State of Health Analysis

Open circuit voltage relaxation to a steady state value occurs, and is measured, at the terminals of a lithium-ion battery when current stops flowing. It is of interest for use in determining state of charge and state of health. As voltage relaxation can take several hours, a representative model and curve fitting is necessary for practical usage. Previous studies of lithium-ion voltage relaxation investigate four characteristics: relationship between voltage relaxation magnitude and state of charge; length of relaxation required; model complexity for state of charge estimation; and model complexity for state of health evaluation. However, previous studies have inconsistent methodology or use only one type of lithium-ion cell, making comparison and generalization difficult. To address this, we conducted 3 h and 24 h voltage relaxation experiments over a range of states of charge on three different lithium ion chemistries (nickel cobalt aluminum NCA; nickel manganese cobalt NMC532; lithium iron phosphate LFP) and fitted them with a new voltage relaxation equivalent circuit model. It was found that a 3 h relaxation period was sufficient for NMC and LFP for state of charge and state of health investigations. Voltage relaxation of the NCA cell continued to evolve past 24 h. It was shown that voltage relaxation shape and magnitude changes as a function of state of charge, and the accuracy of estimating state of charge was explored. Strategically choosing a state of charge for state of health assessment can be optimized to accentuate voltage relaxation magnitude and this differs by chemistry. This suggested technique and experimental findings can be paired with battery degradation studies to determine accuracy of assessing state of health.

Analysis of High-Throughput Electrochemical Impedance Spectroscopy via Hierarchical Bayesian Models

Electrochemical impedance spectroscopy (EIS) is a powerful characterization technique that enables in-situ investigation of electrochemical processes over a wide range of timescales, making it particularly effective in analysis of electrochemical energy conversion devices such as fuel cells and batteries. The advent of automated high-throughput EIS systems presents an exciting opportunity for materials discovery, rapidly providing detailed information about candidate materials. However, the utility of EIS as an electrochemical method is paralleled by the complexity of interpreting the resulting data: overlapping features, noise, and measurement artifacts make EIS spectra notoriously difficult to analyze. Equivalent circuit models (ECMs) are widely used to deconvolute EIS data, but there is significant ambiguity in model selection; meanwhile, the distribution of relaxation times (DRT) has become increasingly popular as an alternative/complementary deconvolution method, but faces similar uncertainty in the choice of regularization parameters. The sheer volume of data produced by high-throughput methods amplifies these challenges, necessitating automated, self-consistent analysis procedures.Here, we discuss high-throughput EIS characterization of protonic ceramic electrode thin films and demonstrate the application of hierarchical Bayesian models for robust analysis of the data. The calibrated hierarchical Bayesian DRT resolves much of the ambiguity in regularization parameters by encoding desired properties of the DRT in prior distributions [1]. Meanwhile, the versatility of the DRT enables appropriate deconvolution of thousands of spectra without predetermined model selection. The DRT may be translated to an ECM for further quantitative analysis of individual relaxation timescales and magnitudes by leveraging a flexible semi-empirical model. In addition, advanced Bayesian DRT models can be implemented to address outliers, sample drift, and multi-spectrum deconvolution. These tools enable conversion of raw spectra to a dataset amenable to further interpretation via machine learning and other methods, thereby expanding opportunities to distill meaningful insight from high-throughput electrochemical studies.

Cyclic GMP-Dependent Regulation of Vascular Tone and Blood Pressure Involves Cysteine-Rich LIM-Only Protein 4 (CRP4).

The cysteine-rich LIM-only protein 4 (CRP4), a LIM-domain and zinc finger containing adapter protein, has been implicated as a downstream effector of the second messenger 3′,5′-cyclic guanosine monophosphate (cGMP) pathway in multiple cell types, including vascular smooth muscle cells (VSMCs). VSMCs and nitric oxide (NO)-induced cGMP signaling through cGMP-dependent protein kinase type I (cGKI) play fundamental roles in the physiological regulation of vascular tone and arterial blood pressure (BP). However, it remains unclear whether the vasorelaxant actions attributed to the NO/cGMP axis require CRP4. This study uses mice with a targeted deletion of the CRP4 gene (CRP4 KO) to elucidate whether cGMP-elevating agents, which are well known for their vasorelaxant properties, affect vessel tone, and thus, BP through CRP4. Cinaciguat, a NO- and heme-independent activator of the NO-sensitive (soluble) guanylyl cyclase (NO-GC) and NO-releasing agents, relaxed both CRP4-proficient and -deficient aortic ring segments pre-contracted with prostaglandin F2α. However, the magnitude of relaxation was slightly, but significantly, increased in vessels lacking CRP4. Accordingly, CRP4 KO mice presented with hypotonia at baseline, as well as a greater drop in systolic BP in response to the acute administration of cinaciguat, sodium nitroprusside, and carbachol. Mechanistically, loss of CRP4 in VSMCs reduced the Ca2+-sensitivity of the contractile apparatus, possibly involving regulatory proteins, such as myosin phosphatase targeting subunit 1 (MYPT1) and the regulatory light chain of myosin (RLC). In conclusion, the present findings confirm that the adapter protein CRP4 interacts with the NO-GC/cGMP/cGKI pathway in the vasculature. CRP4 seems to be part of a negative feedback loop that eventually fine-tunes the NO-GC/cGMP axis in VSMCs to increase myofilament Ca2+ desensitization and thereby the maximal vasorelaxant effects attained by (selected) cGMP-elevating agents.

Correlation of physical aging and glass transition temperatures in ultrathin polystyrene films supported on [formula omitted

This study examined the effects of the aging temperature (Tage) on structural relaxation in ultrathin-supported polystyrene (PS) films with thickness ~0.2Rg. X-ray reflectivity and differential scanning calorimetry were used to evaluate the glass transition temperature (Tg) of ultrathin PS and bulk PS, respectively. The ultrathin films in their confined state showed anomalous thickness relaxation behaviors that could be classified into three types: (1) Tage≤60°C, a slow increase in thickness with time and a decrease in relaxation magnitude with temperature; (2) 70°C≤Tage≤110°C, a slow decrease in thickness with time and an increase in relaxation magnitude with temperature; (3) Tage>110°C, an increase in thickness with time due to dewetting of PS films deposited on SiO2. Such an interesting relaxation behavior can arise from the enhanced dynamics at the surface and reduced mobility at the interface inherent in ultrathin-supported films. Two distinct Tgs peculiar to ultrathin films were confirmed. The lower Tg has not been reported for supported PS films. The relaxation summarized above revealed a strong correlation with the Tg values. The de Gennes modified sliding motion model was applied to explain the correlation with relaxation dynamics.

126. Proximal and distal reciprocal alignment changes following cervical deformity correction

<h3>BACKGROUND CONTEXT</h3> Hyperextension of C0-C2 is a painful compensatory mechanism used to maintain horizontal gaze that is analogous to high pelvic tilt to maintain upright posture. The magnitude and impact of relaxation of this hyperextension following CD correction are not well understood. <h3>PURPOSE</h3> To investigate whether correction of cervical sagittal malalignment allows for relaxation of C0–C2 hyperextension and improved clinical outcome. <h3>STUDY DESIGN/SETTING</h3> Retrospective review. <h3>PATIENT SAMPLE</h3> This study included 65 ACD patients with 1- or 2-year follow-up. <h3>OUTCOME MEASURES</h3> Radiographic alignment, range of motion (ROM). <h3>Methods</h3> CD patients undergoing surgery short of the occiput and the pelvis were included. In addition to the classic alignment parameters, ROM and reserve of extension were calculated across the C2-C7 and C0-C2 segments. After describing the cohort in terms of preoperative information, correlations and hierarchical stepwise regressions investigated the association between C2-C7 correction and change in C0-C2 reserve of extension while controlling for maintenance of horizontal gaze. Stratification by ΔC2-C7 percentile was conducted followed by paired t-tests to investigate changes in TK, C0-C2 and reserve of extension within each percentile. <h3>Results</h3> Sixty-five patients were included (61.8yo±9.6, 68%F). At baseline, they presented with a cervical kyphotic alignment (C2-C7: -11.7°±18.2; TS-CL: 38.6°±18.6), a negative global alignment (SVA: -12mm±71), and hyperlordosis at C0-C2 (33.2°±11.8). The ROM was 25.7°±17.7 and 21.3°±9.9 at C2-C7 and C0-C2, respectively, with an associated reserve of extension of ∼9° for each segment. Limited C0-C2 ROM and reserve of extension significantly correlated with the Neck Disability Index (r=-0.371 & -0.394) and with decreased general health (r=0.455 & 0.512) (all p<0.005) The mean number of levels treated was 7.0±3.1 (24.6% ACDF, 43.1% posterior), with 49.2% of the patients receiving an osteotomy, and 16.9% a 3CO. At 1 year, C2-C7 increased to 5.5°±13.4, SVA became neutral (12mm±54), C0-C2 decreased to 27.7°±11.7, and TK increased to -49.4±18.1 (all p <0.001). At C2-C7 ROM decreased significantly to 9.5°±14.1, and increased to 27.6°±8.1 at C0-C2 without change in reserve of extension. The horizontal gaze significantly improved (4.5±13.3 vs -0.5±9.3 p=0.003). Controlling horizontal gaze, change in C2-C7 lordosis significantly correlated with increased TK (r=-0.615, p<0.01), decreased C0-C2 (r=-0.686, p<0.001), and increased C0-C2 reserve of extension (r=0.414, p<0.015). Larger C0-C2 ROM and reserve of extension correlated with decreased in Neck Disability Index (r=-0.571 & -0.470 p<0.05). Stratification by ΔC2-C7 percentile highlighted the reciprocal change above and below the fusion. Within the lowest percentile (ΔC2-C7: 2°±9.6), no significant difference was noticed between pre and 1 year, while within the highest percentile (ΔC2-C7: -42.8±14.1), C0-C2 decreased (-9.7°±10.5, p=0.001), TK kyphosis increased (14.3°±7.5, p<0.001) and C0-C2 reserve of extension increased (5.8°±6.4, p=0.026). Subanalysis on patients with available 2-year data (N=42) demonstrated similar trends. <h3>Conclusions</h3> Correction of cervical malalignment can significantly impact proximal (C0-C2) and distal (T2-T12) compensation. Restoration of a more natural alignment resulted in an increase of the reserve of extension between C0-C2 and was associated with improved clinical outcomes. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Stress relaxation behaviour of marble under cyclic weak disturbance and confining pressures

Cyclic weak disturbance caused by blasting, drilling, earthquake and transport is an important factor to deep rock projects failure. In order to study the influence of cyclic weak disturbance on the stress relaxation of rock under different confining pressures, a step loading stress cyclic weak disturbance relaxation test was carried out on marble, and an impact factor of weak disturbance was defined. The test results showed that the rock peak strength was the smallest under cyclic weak disturbance relaxation; before the peak stress was reached, the relaxation magnitude of weak disturbance increased with the increase of the initial stress level; and it continuously increased with the decrease of the initial stress level after the peak stress. The stress relaxation rate nonlinearly decreased with axial strain levels; by contrast, the initial stress relaxation rate was proportional to the strain level. As the strain increased, the weak disturbance effect presented a nonlinear growth characteristic of first decreasing and then increasing.

Structure, composition and fibril-reinforced poroviscoelastic properties of bovine knee ligaments and patellar tendon.

Tissue-level stress-relaxation of ligaments and tendons in the toe region is characterized by fast and long-term relaxations and an increase in relaxation magnitude with strain. Characterizing the compositional and structural origins of these phenomena helps in the understanding of mechanisms of ligament and tendon function and adaptation in health and disease. A three-step tensile stress-relaxation test was conducted on dumbbell-shaped pieces of bovine knee ligaments and patellar tendon (PT) (n = 10 knees). Their mechanical behaviour was characterized by a fibril-reinforced poroviscoelastic material model, able to describe characteristic times and magnitudes of fast and long-term relaxations. The crimp angle and length of tissues were measured with polarized light microscopy, while biochemical contents were determined by colorimetric biochemical methods. The long-term relaxation time was longer in the anterior cruciate ligament (ACL) and PT compared with collateral ligaments (p < 0.05). High hydroxyproline content predicted greater magnitude and shorter time of both fast and long-term relaxation. High uronic acid content predicted longer time of long-term relaxation, whereas high crimp angle predicted higher magnitude of long-term relaxation. ACL and PT are better long-term stabilizers than collateral ligaments. The long-term relaxation behaviour is affected or implied by proteoglycans and crimp angle, possibly relating to slow structural reorganization of the tissue.

Effects of trans- versus cis-resveratrol on adrenergic contractions of the rat tail artery and role of endothelium.

The health benefits of the natural polyphenol trans‐resveratrol may play an important role in preventing a variety of diseases. Resveratrol has been shown to reduce blood pressure and improve metabolic diseases such as type 2 diabetes mellitus and obesity. Our previous studies examined the role of K+ channels in the vasorelaxation responses to trans‐resveratrol in the rat tail artery. During these studies, we uncovered a novel transient contraction prior to the sustained relaxation effect of trans‐resveratrol. Thus, the purpose of this study was to determine the role of the endothelium in these vascular contraction and relaxation responses to trans‐resveratrol. We additionally sought to determine if the cis‐isomer of resveratrol exerts any of the same vascular effects as the trans‐isomer. The vascular responses to trans‐resveratrol were examined in rat tail arteries with intact or denuded endothelium over a 2‐hr period. Additionally, the vascular responses to trans‐ and cis‐resveratrol were compared in rat tail arteries with intact endothelium. Both the transient contractile response and the persistent relaxation response to trans‐resveratrol were similar in the arterial rings with intact or denuded endothelium. There was a significant correlation between the initial contraction‐enhancing action of trans‐resveratrol and the magnitude of the sustained relaxation for vessels with both intact and denuded endothelium. Moreover, we demonstrated that cis‐resveratrol produced a significantly greater relaxation response as compared to trans‐resveratrol without the initial contractile response. These data demonstrate the role of the vascular smooth muscle in the vascular responses to resveratrol and the potential clinical benefits of the cis‐isomer of resveratrol as compared to the trans‐isomer.

Geometry relaxation-mediated localization and delocalization of excitons in organic semiconductors: A quantum chemical study.

Photo-induced relaxation processes leading to excimer formations or other traps are in the focus of many investigations of optoelectronic materials because they severely affect the efficiencies of corresponding devices. Such relaxation effects comprise inter-monomer distortions in which the orientations of the monomer change with respect to each other, whereas intra-monomer distortions are variations in the geometry of single monomers. Such distortions are generally neglected in quantum chemical investigations of organic dye aggregates due to the accompanied high computational costs. In the present study, we investigate their relevance using perylene-bisimide dimers and diindenoperylene tetramers as model systems. Our calculations underline the importance of intra-monomer distortions on the shape of the potential energy surfaces as a function of the coupling between the monomers. The latter is shown to depend strongly on the electronic state under consideration. In particular, it differs between the first and second excited state of the aggregate. Additionally, the magnitude of the geometrical relaxation decreases if the exciton is delocalized over an increasing number of monomers. For the interpretation of the vibronic coupling model, pseudo-Jahn-Teller or Marcus theory can be employed. In the first part of this paper, we establish the accuracy of density functional theory-based approaches for the prediction of vibrationally resolved absorption spectra of organic semiconductors. These investigations underline the accuracy of those approaches although shortcomings become obvious as well. These calculations also indicate the strength of intra-monomer relaxation effects.

Water splitting on the mesoporous surface and oxygen vacancies of iron oxide generates electricity by hydroelectric cell

The impact of water splitting by specially processed maghemite/iron oxide for generating ecologically sustainable, low-cost green electricity is a vital step. In the present work, a facile and a low-cost chemical synthesis technique has been adopted to produce versatile, oxygen deficient, mesoporous maghemite (iron oxide) nanostructure. The maghemite nanoparticles have been synthesized by the oxidation of magnetite nanoparticles, using a coprecipitation technique followed by heat treatment at elevated temperature 350 °C for 2 h. In the modified process, oxygen (VO) and iron vacancies (VFe) in maghemite have been systematically created. The VFe sites generated at octahedral sites due to Fe2+ ion oxidation has been estimated by Raman and X-ray photoelectron spectroscopy (XPS). Water splitting is prominently occurring at VO sites. Splitting of polar water molecules on the surface oxygen vacancies of nanoporous ferrite and metal oxide pellets has been translated into a primary hydroelectric cell by attaching two dissimilar electrodes to the pellets to generate an electric current. However, preferable associative water adsorption on VFe sites have been confirmed by unique XPS bands with multilayered physisorbed water adsorption modes. The role of VFe, VO sites in water molecule dissociation, and further dissociated ions diffusion kinetics through respective maghemite and magnetite pellets has been thoroughly explored by dielectric measurements. Maghemite based hydroelectric cell (HEC) has delivered a maximum current of 19 mA and emf 0.85 V by using only 200 μL water. The maximum electrical power 16.15 mW delivered by maghemite HEC is 0.58, 0.42 times lower than the respective magnetite, hematite HECs. The magnitude of dielectric relaxation is reduced in maghemite due to preferable associative water adsorption on VFes compared to other iron oxides. Hence, lesser VO concentration, larger average pore size along with the presence of hydrophobic VFe sites are responsible for the lower performance of maghemite based HEC. Variation in spinel magnetite, maghemite HEC performance has been analysed by simulating its V–I characteristic curve. The electricity generation by maghemite HEC is reduced due to lower VO concentration along with the presence of hydrophobic VFe sites reducing the overall number of dissociated ions. Hydroelectric cell from earth- abundant iron oxide is an eco-friendly, bio-compatible, and cost-effective green energy source by water splitting at room temperature.

Behavior of Phosphorus Donors in Bulk Single-Crystal Monoisotopic 28Si1 – x72Gex Alloys

The behavior of phosphorus donors in bulk single-crystal monoisotopic Si1 – xGex alloys (x = 0.0039–0.05) enriched by zero-spin isotopes 28Si (99.998%) and 72Ge (99.984%) by the electron-spin-resonance method is investigated. The hyperfine structure of the donor-electron spectrum giving information on the density of the donor wave function in the ground state on the 31P nucleus (I = 1/2) as well as the temperature dependences of the spin-relaxation rate (T = 3.5–30 K), which make it possible to analyze the longitudinal component T1 relaxation mechanism and magnitude of the valley–orbit splitting of the donor state, are investigated. Interest in these investigations is also caused by the fact that the Si1 – xGex alloy enriched by zero-spin isotopes (28SiisoGe, iso = 70, 72, 74, 76) is a poorly known material when compared with 28Si. The irregular arrangement of germanium atoms in the lattice of the SiGe solid solution and local distortions formed by it can level isotopic effects under isotopic enrichment. However, despite broadening of the lines of the electron-spin resonance of donor electrons due to random deformations formed by dissolved germanium atoms in silicon, narrower lines of the spectra of the electron-spin resonance are observed in isotopically pure Si1 – xGex single crystals at x = 0.39, 1.2, 2.9 at % when compared with similar crystals with the natural composition of silicon and germanium isotopes.

Uniaxial stress relaxation behavior of marble after cyclic disturbance loads

It is known that time-dependent rheological deformation of rocks is influenced by cyclic disturbance loads. However, the stress relaxation behavior after cyclic disturbance is still poorly understood. To study such effects, a dynamic disturbance electrohydraulic servo triaxial test system was developed. A series of disturbance relaxation tests with different disturbance numbers and amplitudes were carried out on marble at several strain levels. The influence of cyclic disturbance parameters on the relaxation magnitude, relaxation rate, and peak stress was analyzed. Relaxation magnitude and relaxation rate after cyclic disturbance loads are larger than those of conventional relaxation. In addition, sensitivity analysis reveals that the relaxation magnitude is more sensitive to the disturbance amplitude. Damage variables defined by the plastic strain method can well reflect the evolution law of relaxation damage under different disturbance conditions. It is believed that the damage model constructed by Harris function can better describe the relaxation damage evolution law at various strain levels.

Delamination Morphology Maps of Chromium Oxide Scales Formed on Cr-Based Alloys

The delamination processes occurring in chromia scales formed on Ni-30Cr and Fe-47Cr alloys were studied. Delamination is the result of the competition between growth stresses evolution during heating, thermal stresses during cooling, and stress release phenomena, leading to high residual stress in the oxide film. Delamination in chromia has been found to occur due to type and amount of residual stresses generated at the end of heating-induced chromia growth and subsequent cooling-induced differential shrinkage. The mapping of the residual stresses in the oxide films at the microscopic scale around the delaminations allow to classify the latter into three different groups: buckles of Type 1, buckles of Type 2, and spalls. Using the stress relaxation magnitude, an assessment of the interfacial toughness of the metal/oxide systems was carried out, thanks to the buckling and crack propagation theory in the oxide. From the value obtained, microscopic observations, and the residual stress maps, a diagram describing the spalling of the buckles for chromia scales is proposed, as well as the delamination maps of Fe-47Cr/Cr2O3 and Ni-30Cr/Cr2O3 systems specifying the conditions of existence of the obtained delamination features.

Is Blue Light the Next Little Blue Pill?: Effects of Light‐Stimulation on Erectile Dynamics

INTRODUCTIONMany major risk factors for erectile dysfunction (ED) are associated with depressed nitric oxide (NO) availability. Phosphodiesterase type 5 inhibitors are the current first line therapy for ED and are ineffective in 30–50% of patients, largely due to impaired NO production. New therapeutic approaches for ED are needed under such conditions. The phenomenon of light‐stimulated vasodilation has recently been described in aortic tissue, which is enhanced by G‐protein coupled receptor kinase 2 (GRK2) inhibition and particular for blue light. The objective of this project was to determine if this GRK2 sensitive photorelaxation response is active in erectile tissue and the contribution of the NO signaling pathway to the response.METHODSYoung male mice (n = 4–8 / experiment) were sacrificed and erectile tissue was harvested from the shaft of the penis. Ex vivo constriction and relaxation responses were assessed in a muscle strip myograph. The GRK2‐sensitive photorelaxation response was assessed ± 1 μM GRK2 inhibitor using nine different wavelengths (365–700 nm) of light at constant intensity (100 Lux), and then at nine different light intensities (1–1000 Lux) at 455 nm. The contribution of the NO signaling pathway to the GRK2‐sensitive response was tested with stimulations of 20 and 100 Lux at 455 nm with 1 μM GRK2 inhibitor ± the NO synthase inhibitor L‐NAME, the soluble guanylate cyclase (sGC) inhibitor ODQ, the protein kinase G (PKG) inhibitor Rp‐8‐Br‐cGMPS, or the NO scavenger cPTIO, as well as in tissue from mice with a deletion of endothelial + neuronal NO synthase. Differences in responses were determined by two‐way repeated measures ANOVA followed by Sidak’s post hoc test where appropriate.RESULTSMaximal relaxation responses at 455 nm increased with increasing light intensity in the absence (2–10%) and presence (57–103%) of the GRK2 inhibitor, demonstrating a stark increase in photorelaxation under GRK2 inhibition. However, this response waned more rapidly at intensities &gt; 100 Lux. Significant GRK2‐sensitive responses were observed at 365, 395, 430, and 455 nm at 100 Lux intensity, with no significant responses observed in the 490–700 nm range. Both L‐NAME and deletion of endothelial/neuronal NO synthase increased the magnitude of relaxation at all time‐points at 20 Lux, and prolonged maximal relaxation at 100 Lux. CPTIO prolonged the relaxation response at both intensities. ODQ drastically blunted the photorelaxation response at all time points and intensities. Rp‐8‐Br‐cGMPS had no effect on photorelaxation.CONCLUSIONSGRK2‐sensitive photorelaxation was determined to be optimal in the 430–455 nm (violet‐blue) range at ~100 Lux. Depletion of NO by scavenging, enzyme inhibition or genetic deletion enhanced the response, which is sGC‐dependent but PKG‐independent. These findings have implications for treatment of ED due to low NO availability if the GRK2‐sensitive photorelaxation pathway can be harnessed therapeutically.