Changes In Structural Parameters Research Articles

A DFT study on the mechanism of acetaldehyde generation during vinyl acetate synthesis from gas-phase ethylene acetoxylation on Pd/Au (100) surface

Acetaldehyde (CH3CHO) is an important by-product in the reaction of ethylene to vinyl acetate (VAC). However, the mechanism of the generation of CH3CHO has been little studied. In this paper, we designed a reaction network for the possible generation of acetaldehyde from intermediate species on Pd/Au catalysts, including three reaction paths. Stable adsorption configurations of the species involved in each elementary reaction were identified by Density Functional Theory (DFT) calculations and the charge changes on the catalyst surface during the adsorption process as well as the structural parameter changes of the adsorption configurations were compared. Based on this, we calculated the kinetic parameters on three reaction paths and combined with Kinetic Monte Carlo (KMC) simulations to found the dominant path and rate-determining step to help understand the mechanism of acetaldehyde generation on the surface of Pd/Au (100). Results suggest that species involved in the reactions are adsorbed mainly on Pd-Au bridge sites, Pd top sites, and Pd-Pd intermediate vacancies and species structure changes after adsorption. CHCH, CH2CH, and CH3CH could all generate CHxCHO by reacting with O species or OH species, and the energy barrier for reactions with O species are all lower than those for reactions with OH species. The dominant pathway for acetaldehyde generation on Pd/Au (100) surface is CH2CH2 → CH2CH→ CH2CHO → CH3CHO and the ethylene dehydrogenation elementary reaction is the rate-determining step.

Experimental research on damage identification of fully free beams based on modal shapes

Ship damage identification is a new field of ship research, which is of great significance to damage control, life and property safety and strategic decision-making, but there is no effective method for ship damage identification. The structural system changes caused by ship damage are usually represented by the change of system mass, stiffness and energy dissipation characteristics, and then the change of structural dynamic characteristic parameters, which provides a theoretical basis for ship damage identification. In this paper, the ship is simplified as a beam model with fully free boundary conditions. Based on the dynamic characteristic parameter of the modal shape, the damage identification of the ship under six damage conditions is carried out through numerical simulation and experimental verification by using COMAC and the derived indexes of curvature mode and modal flexibility. The results show that the first four orders of curvature mode difference mean index and the curvature index of modal flexibility change rate can accurately locate the damage of hull beam structure; The damage degree of hull beam can be identified by the change of curvature mode difference index, but there are some errors in this method; The curvature index of modal flexibility change rate is positively correlated with the damage degree, which can reflect the damage degree of the structure. The research results of this paper can provide new methods and ideas for hull beam damage identification.

Study on the mechanical properties and pore structure of granulated blast furnace slag self-compacting concrete based on grey correlation theory

ABSTRACT Variations in the mechanical properties and pore structure of granulated blast furnace slag self-compacting concrete were studied. The grey correlation theory established the relationship between mechanical properties and pore structure. The test results show that with the continuous improvement of age, the mechanical properties decreased with the increase of sand replacement rate in the early stage. In the middle and late stages, the compressive strength and splitting tensile strength of granulated blast furnace slag self-compacting concrete are higher than those of ordinary self-compacting concrete, while the elastic modulus continues to decrease with increasing slag content. After standard curing, the change in the pore structure parameters of ordinary self-compacting concrete is relatively stable. The pore structure parameters of granulated blast furnace slag self-compacting concrete change significantly. Because granulated blast furnace slag has a certain hydraulicity, the strength and strength growth rate of granulated blast furnace slag self-compacting concrete are higher than those of ordinary self-compacting concrete, and the corresponding pore structure parameters change. Through grey correlation analysis, the specific surface area and average chord length structure of granulated blast furnace slag self-compacting concrete are essential factors affecting its mechanical properties.

Long-term continuous automatic modal tracking algorithm based on Bayesian inference

Modal tracking plays a vital role in structural health monitoring since changes in modal parameters help us understand a structure’s dynamic characteristics and may reflect the potential deterioration of structural performance. Although numerous modal parameter estimation (MPE) methods exist, it is not guaranteed that an MPE process will exclude all spurious modes and not lose any physical modes every time over a long-term monitoring period. Relatively large damping of a structure, poor data quality, and significant changes in structural modal parameters may make the estimated modal parameters spurious, missing, or misclassified. It makes long-term modal tracking semiautomated or manual, which constrains timely downstream applications such as anomaly detection, condition assessment, and decision making. This research aims to propose a long-term continuous automatic modal tracking algorithm based on Bayesian inference even when the modal parameters, damping, and data quality change significantly. Bayesian inference is used to determine the physical modes from the results of existing MPE methods. Both the modes identified from the most recent response set and the modal probability model from multiple previous response sets are considered in the Bayesian model to better determine the physical modes from the results of MPE. Moreover, the proposed algorithm requires only three extra hyperparameters compared to general modal tracking algorithms, and they can be quickly determined by a grid search method. The performance of the proposed algorithm is verified by a numerical example and a real-world civil structure Z24 Bridge benchmark.

Important role of a few large-diameter tree species in basal area and its increase in an old-growth deciduous broadleaf forest in Japan

Because of their large diameter and biomass, old-growth forests provide valuable wood and high levels of ecosystem services (e.g., carbon sinks). Most of the aboveground biomass or basal area (BA) in old-growth forests is provided by small numbers of large-diameter trees. If the diversity of these trees is lower in temperate forests than in tropical forests, then the BA of temperate forests should be dominated by small numbers of large-diameter species. To explore how and to what extent BA and increase in BA (ΔBA) are determined by species with large diameters in temperate old-growth forests, we examined changes in the size structure and demographic parameters of large-diameter tree species based on 11 years of diameter at breast height (DBH, ≥ 5 cm) records for a 6-ha plot in an old-growth deciduous broadleaf forest in Japan. To estimate the extent to which difference in the successional status affect future ΔBA, we compared demographic parameters between them. Individuals with DBH ≥ 50 cm represented only 4.2% of all trees; however, their relative BA (rBA, ratio of BA of individual trees to the BA of entire forest) and relative increase in BA (rΔBA, ratio of increase in BA of individual trees to increase in BA of entire forest) were 36.4% and 25.1%, respectively, indicating that both BA and ΔBA were dominated by a small number of large trees. The rBA and rΔBA of the four species with the highest maximum DBH (DBHmax) were 71.1% and 61.4%, respectively, indicating that BA and ΔBA were also dominated by a very small number of species with exceptionally high DBHmax. Even among individuals with DBH ≥ 50 cm, the top four species in terms of DBHmax represented 90.0% and 80.6% of the total BA and ΔBA, respectively, confirming that both BA and ΔBA are highly dependent on species with high DBHmax values irrespective of the successional status. Most of the top 10 species in terms of DBHmax also showed increasing diameter growth rates and survival rates with increases in DBH class. Although the species with the second-highest DBHmax value had relatively low BA and ΔBA, BA gain exceeded BA loss for 11 years, thereby increasing the overall BA of the forest. These findings suggest that small numbers of large-diameter tree species play an important role in the sustainable increase in biomass among temperate old-growth forests in Japan. However, late successional species have higher rates of gain in BA, lower mortality, and higher recruitment rates than mid successional and early succesional species, indicating that their populations are increasing strongly. It is expected that the late successional species will eventually become more dominant than the mid and early successional species, unless there occurs some large-scale disturbance.

Research on structural optimization of low viscosity automatic inflow controller

The study on AICD structure optimization is an ongoing research issue. Reasonable structural is conducive to improve the water control performance of the device. However, the existing structural optimization methods ignore the influence of multiple factors. In order to further improve the water control effect, a low viscosity AICD was designed, and the orthogonal test was introduced to optimize its structure. The optimal structure of AICD under different viscosity conditions was defined. The significant degree of each structure on the water control performance was clarified. The influence law on the flow field distribution in AICD by the change of structure parameters was revealed by visualizing pressure and streamline field. The water control performance of original model and optimization model was analyzed and evaluated by the water–oil pressure loss difference. The results showed that the optimal structure of AICD changes under different viscosity conditions. The outlet diameter is the most influential factor. Reducing the outlet diameter is beneficial to increasing the rotational distance of the fluid in the disk and enlarging the water–oil pressure loss difference. Distributary channel width is a secondary factor. The reasonable size contributes to improve the water split ratio in the annular channel. There is a certain correlation between the intake angle and the oil viscosity. It is recommended to adopt a large intake angle in the case of high oil viscosity. The water–oil pressure loss difference of the AICD obtained by orthogonal test under different conditions is improved by two times compared with that before optimization. It can be seen that the optimization of AICD by orthogonal test greatly improves the water control performance of the device.

Layer structure-based grain refinement mechanism and its effect on the mechanical behavior of Ti/Al laminated metal composites

In this study, the effect of layer structure on the mechanical behavior of Ti/Al laminated metal composites (LMCs) was explored, focusing on the occurrence of an additional strengthening mechanism introduced by heterogeneous microstructures between constituent layers. Experimental results showed that the change in layer structure parameters and rolling conditions had a significant effect on the microstructure of the Al layer, and the difference in shear strain scale near the interface led to the formation of a grain refinement zone (GRZ) with various microstructural characteristics during dynamic recrystallization. In addition, the recrystallized distribution and texture evolution (i.e., the increasing recrystallized fraction and the intensifying shear texture r-Cube {001} 〈110〉) revealed that the deformation storage energy as the driving force of recrystallization played an important role in the difference in the heterogeneous degree formed in various Ti/Al LMCs. On the other hand, the strength deviation between the experimental strength and the theoretical strength predicted by the rule of mixture can be detected in all LMCs with different thickness ratios after hot rolling, resulting from the pile-up of geometrically necessary dislocations (GNDs) caused by the synergetic deformation induced by mechanical incompatibility between Ti and Al layers during plastic deformation. With a change in the layer structure parameter, a considerable strength deviation in the Ti/Al LMC with a large thickness ratio indicated that the high mechanical incompatibility between the constituent layers was conducive to the enhancement of additional strengthening behavior.

Optical coherence tomography angiography biomarkers in a bi-monthly maintenance dosing aflibercept in patients with neovascular age-related macular degeneration

PurposeTo evaluate the correlations between swept-source optical coherence tomography angiography (SS-OCTA) parameters and clinical outcomes in eyes with neovascular age-related macular degeneration (nAMD) administered a bimonthly intravitreal aflibercept regimen.MethodsThis prospective, single-arm, interventional study enrolled 33 patients with treatment-naïve nAMD. The eyes received three monthly aflibercept injections followed by five bi-monthly regimens (total 50 weeks). The structural parameters including central subfield thickness (CST) and 5 mm pigment epithelial detachment (PED) volume and microvascular parameters including macular neovascularization (MNV) area, vessel density (VD), and vessel length density (VLD) were recorded every before and 1 week after treatment.ResultsPatients who gained > 5 letters of best-corrected visual acuity (BCVA) from the baseline showed greater decreases in VD and VLD during the loading phase. Patients without recurrent or persistent fluid during the maintenance phase showed greater decreases in CST and 5 mm PED volume after the first injection. The decrease in mean VD during the loading phase was significantly correlated with the final BCVA (r = -0.820, p = 0.004). Moreover, the decrease in mean VLD during the loading phase was significantly correlated with the improvement in the final BCVA (r = -0.726, p = 0.017).ConclusionsThe decrease in mean VD during the loading phase was significantly negatively correlated with the final BCVA at the last visit. The decrease in mean VLD during the loading phase, mean CST during the loading phase, and the improvement in final BCVA showed significant correlations. Therefore, early changes in OCTA microvascular and OCT structural parameters could help predict clinical outcomes in nAMD.Trial RegistrationThe trial was registered with the Clinical Research Information Service (CRIS), which joined the WHO International Clinical Trials Registry Platform (ICTRP) (Registration number: KCT0007375, Date of first trial registration: 10/06/2022).

Effect of reinforcing flexible biofriendly ternary polymer blend film with bio ionic liquid on structural, thermal and low-frequency dielectric properties for multifunctional biomedical and soft electronics applications

ABSTRACT In present work the effect of reinforcing choline acetate in PVC-PVP-50%PPy on structural, morphological, mechanical, thermal, electrical and low-frequency dielectric properties of base matrix is studied. Synergistic changes in structural, morphological, mechanical, thermal properties and dielectric parameters in low-frequency region of the host matrix are seen. Disk diffusion test for Escherichia coli and Bacillus subtilis shows that the blend film reinforced with Choline acetate showed their benign nature toward bacteria indicating their potentiality to be used for various scale multifunctional dielectric and electrical applications working in close contact with living matter, green electronics and various health monitoring systems.

Sound absorption performance based on auxetic microstructure model: A parametric study

With the increasing prominence and complexity of environmental noise problems, there is an urgent need for novel acoustic materials to meet noise reduction requirements. In this paper, two auxetic microstructures and three typical lattice microstructures are established, and a microscopic-macroscopic acoustic performance study scheme is established through the Johnson-Champoux-Allard-Pride-Lafarge (JCAPL) model. Auxetic-BCC porous materials have lower acoustic resistance and reactance amplitudes than many typical porous materials through experimental verification and comparative analysis of numerical calculations. The porous material's thickness and the backing cavity's thickness have similar effects on sound absorption performance when controlling a single change in structural parameters, and there is an optimum thickness. As acoustic resistance and reactance are dominant at low and high frequencies, respectively, noise reduction is better at low (high) frequencies than at minor (large) porosity, and the porosity of 76.4%–82.0% has the best sound absorption effect. Changes in prism length of materials with high porosity are more sensitive than those with low porosity, so the prism length with porosity of 76.4%, 79.0%, and 82.6% shall be designed to be less than 1.1 mm, 0.9 mm, 0.8 mm, respectively. This study provides theoretical guidance for designing multifunctional porous materials in extreme environments.

A theoretical study on the filtration efficiency and dust holding performance of pleated air filters

Filter media composed of electrostatically charged nonwovens is the key device in an air purifier. Pleated filters are constructed from a cardboard frame with lattice faces containing a filter media reinforce by an expanded support grid, which have more surface area for trapping contaminants and capture airborne contaminants more effectively than non-pleated air filters. The aim of this work is to investigate the dominant factors on the filtration efficiency and dust holding performance of pleated filter by using a modified numerical model. It is found that geometric parameters of pleated filter play important roles to efficiency of the air purifier based on particle loading and filtration efficiency. The stable structural parameters include bending angle of pleated filter material in the range of 0∼60° and the ratio of bending portion less than 0.5. Lower filling degree and shorter length of pleated filter unit exhibit similar stability of efficiency, indicating that the change of structural parameters has little effects on the filtration performance. The knowledge obtained in this work provides concrete reference for the design of high-performance air-cleaner element.

Tailoring of Optical, Dielectric, and Structural Parameters of PVA by CdS-Ag Core-Shell Nanoparticles and UV Irradiation

Chemical reduction process was employed for formation of CdS-Ag CSNs. Consequently, different weight % of these core shells were embedded in PVA. Further, these films were exposed with UV radiation and changes in optical, structural and dielectric parameters were observed. XRD and TEM was done to establish formation of CSNs. By evaluation of UV–vis data band gap of PVA was observed to reduce after embedding CSNs and linear and non-linear optical parameters like n0, χ[1], χ[3], n2 were discussed corresponding to weight % and UV exposure. Effect of weight % of CSNs and UV on structure, ac conductivity and dielectric parameters is discussed in detail.

Improved Structural Health Monitoring Using Mode Shapes: An Enhanced Framework for Damage Detection in 2D and 3D Structures

Structural health monitoring (SHM) is crucial for ensuring the safety and performance of offshore platforms. SHM uses advanced sensor systems to detect and respond to negative changes in structures, improving their reliability and extending their life cycle. Model updating methods are also useful for sensitivity analysis. It is feasible to discuss and introduce established techniques for detecting damage in structures by utilizing their mode shapes. In this research, by considering reducing the stiffness of elements in the damage scenarios, we conducted simulations of the models in MATLAB, including both two-dimensional and three-dimensional structures, to update the method suggested by Wang. Wang’s method was improved to produce a sensitivity equation for the damaged structures. The sensitivity equation solution using a subset of mode shapes data was found to evaluate structural parameter changes. Comparing the updated results for Wang’s method and the suggested method in the two- and three-dimensional frames showed a noticeable modification in damage recognition. Furthermore, the suggested method can update a model containing measurement errors. Since Wang’s damage detection formulation is suitable only for 2D structures, this modified framework provides a more accurate decision-making tool for damage detection of structures, regardless of whether a 2D or 3D formulation is used.

Association between early changes of left atrial volume and right ventricular function after transcatheter edge-to-edge repair for mitral regurgitation

Abstract Funding Acknowledgements Type of funding sources: None. Background Transcatheter edge-to-edge repair (TEER) has recently become a therapeutic option for patients with severe mitral regurgitation (MR) who are unsuitable for surgery, in order to improve clinical outcomes. MR is a determinant of structural and functional changes of all cardiac chambers. The left atrium (LA) and the right ventricle (RV) play an important role in the pathogenesis of symptoms in patients affected by severe MR. Recent data suggests that reverse changes of left ventricle (LV), as well as LA and RV, are associated to reduced morbidity and mortality. Purpose The aim of the study is to test the association between changes of LAV and RV function early after TEER. Methods This is a retrospective study that enrolled patients with chronic functional severe MR, at high surgical risk, who underwent TEER between February 2015 and July 2022. We evaluated the changes of LA and RV function between baseline and before discharge and their relation with symptoms. Results A total of 52 patients were included (mean age 65.2 ± 10.2 years; 69% males, mean left ventricular ejection fraction [LVEF] 28.8 ± 5.7%). No differences of baseline clinical and echocardiographic characteristics were detected between the groups of patients who had LA volume (LAV) reduction (n = 31) and those who did not (n = 21), including symptoms assessed with New York Heart Association (NYHA) classification. However, the former group had a significant higher LA size (LAVI 76.6 ± 18.2 vs. 61.2 ± 17.6 mL/m2, p = 0.004). In the overall population, we observed a significant increase in tricuspid annular plane systolic excursion (TAPSE), S’ wave at Tissue Doppler and ratio between TAPSE and pulmonary artery systolic pressure (TAPSE/PASP), as well as a decrease of PASP (respectively, p = 0.034, p = 0.003, p < 0.001 and p < 0.001). Compared to patients who did not have LAV reduction, those who had showed a significant increase of TAPSE/PASP (from 0.40 ± 0.17 to 0.52 ± 0.21 mm/mmHg, p = 0.002), S’ wave (from 8.7 ± 1.6 to 9.4 ± 1.7 cm/s, p = 0.005) and a decrease of PASP (from 50.3 ± 14.3 to 38.9 ± 11.5 mmHg, p < 0.001). The absolute change of LAV from baseline to discharge was associated with the change of PASP (b coefficient 0.55, 95% confidence interval 0.09, 1.02, p = 0.022) and TAPSE/PASP (b coefficient −4.06, 95% confidence interval −7.78, −0.33, p = 0.033), even after adjustment for covariates (respectively, b coefficient 0.61, 95% confidence interval 0.07, 1.14, p = 0.027 and b coefficient −4.82, 95% confidence interval −9.43, −0.23, p = 0.040). Finally, NYHA class significantly improved in the group of patients whose LAV reduced (p = 0.011). Conclusion In this retrospective study, an association between early changes of LA structure and RV functional parameters has been described. After TEER, RV function improved, especially in patients who had LAV reduction. In the latter, we observed an improvement of NYHA functional class.

Effects of sacubitril/valsartan on atrial function and structure as treatment response indicators in patients with heart failure with reduced ejection fraction: an observational prospective study

Abstract Funding Acknowledgements Type of funding sources: None. Background Sacubitril/valsartan (Sac/Val) has been shown to improve mortality and reduce hospitalizations in patients with heart failure with reduced ejection fraction (HFrEF), also through reverse cardiac remodeling. However, temporal changes of functional and structural left atrial parameters, including speckle tracking (ST) analysis, have not been comprehensively characterized yet. Purpose This prospective study sought to: (1) evaluate the impact of Sac/Val on echo parameters, focusing on left atrial function and structure metrics, at two timepoints, 6 and 12 months, after treatment initiation; (2) assess the predictive role of these factors on Sac/Val response at 12 months, including LVEF and biomarker outcomes. Methods From January 2020 to September 2021, HFrEF patients from Policlinico Universitario Agostino Gemelli IRCSS outpatient HF service with indication to Sac/Val treatment were prospectively enrolled; subjects with history of atrial fibrillation and more than moderate mitral regurgitation were excluded. Echocardiographic evaluation was performed before Sac/Val, at 6 and 12 months after treatment initiation. Patients with improvement in left ventricular ejection fraction (LVEF) ≥ 35% and with N-terminal pro-b-type natriuretic peptide (NT pro-BNP) reduction below 1000 pg/mL were considered responders. Results Sixty-six patients (50 males, 16 females) with an age of 64 ± 12 years were finally enrolled, of which 41% were affected by chronic ischemic heart disease. At enrollment, 19 subjects were in New York Heart Association class III-IV, median NT-proBNP was 3063.00 pg/mL and mean LVEF was 30.3±7.7%. LA-EF was 27.8±12.8%, while Left Atrio-ventricular coupling index (LACi) was 0,30±0,12. At ST echocardiography, LV GLS was -8,2±3,0% and LA reservoir strain (LARS) 11,60%. All structural and functional LA parameters significantly improved at T1 and T2: at T2, LARS was 22,51%, LA-EF 37,4±15,8% and LACi 0,28±0,12 (respectively p <0,001, p = 0,05, p = 0,018 compared to baseline). No differences were detected according to dysfunction etiology. Improvements were larger among patients who achieved the pre-specified outcome. LA reservoir strain was the best predictor of positive changes in LVEF and NT-proBNP. Conclusions Precise characterization of LA structural and functional parameters, including ST analysis, may help identifying patients experiencing the highest benefit from Sac/Val, therefore guiding treatment in the HFrEF population.

Isolated and solvated chiroptical behavior in conformationally flexible butanamines.

The nonresonant optical activity of two highly flexible aliphatic amines, (2R)-3-methyl-2-butanamine (R-MBA) and (2R)-(3,3)-dimethyl-2-butanamine (R-DMBA), has been probed under isolated and solvated conditions to examine the roles of conformational isomerism and to explore the influence of extrinsic perturbations. The optical rotatory dispersion (ORD) measured in six solvents presented uniformly negative rotatory powers over the 320-590 nm region, with the long-wavelength magnitude of chiroptical response growing nearly monotonically as the dielectric constant of the surroundings diminished. The intrinsic specific optical rotation, (in deg dm-1 [g/mL]-1 ), extracted for ambient vapor-phase samples of R-MBA [-11.031(98) and -2.29 (11)] and R-DMBA [-9.434 (72) and -1.350 (48)] at 355 and 633 nm were best reproduced by counterintuitive solvents of high polarity (yet low polarizability) like acetonitrile and methanol. Attempts to interpret observed spectral signatures quantitatively relied on the linear-response frameworks of density-functional theory (B3LYP, cam-B3LYP, and dispersion-corrected analogs) and coupled-cluster theory (CCSD), with variants of the polarizable continuum model (PCM) deployed to account for the effects of implicit solvation. Building on the identification of several low-lying equilibrium geometries (nine for R-MBA and three for R-DMBA), ensemble-averaged ORD profiles were calculated at T = 300K by means of the independent-conformer ansatz, which enabled response properties predicted for the optimized structure of each isomer to be combined through Boltzmann-weighted population fractions derived from corresponding relative internal-energy or free-energy values, the latter of which stemmed from composite CBS-APNO and G4 analyses. Although reasonable accord between theory and experiment was realized for the isolated (vapor-phase) species, the solution-phase results were less satisfactory and tended to degrade progressively as the solvent polarity increased. These trends were attributed to solvent-mediated changes in structural parameters and energy metrics for the transition states that separate and putatively isolate the equilibrium conformations supported by the ground electronic potential-energy surface, with the resulting displacement of barrier locations and/or decrease of barrier heights compromising the underlying premise of the independent-conformer ansatz.

Differences in rate of change of retinal structural and microvasculature parameters in parkinson’s disease compared to controls

AbstractBackgroundPrior cross‐sectional studies have revealed decreased macular perfusion density (PFD) and increased peripapillary PFD in Parkinson’s disease (PD). We assess longitudinal rate of change of retinal microvascular and structural parameters in PD vs controls with normal cognition.MethodSubjects were imaged using Zeiss Cirrus HD‐5000 AngioPlex. Those with confounding medical or ocular comorbidities were excluded. Superficial capillary plexus (SCP) PFD and vessel density (VD) were assessed within ETDRS 6×6 circle, inner ring, outer ring and 3×3 circle and inner ring. SCP foveal avascular zone (FAZ) area was assessed. PFD, VD, FAZ, peripapillary retinal nerve fiber layer (RNFL), ganglion cell‐inner plexiform layer (GCIPL), and central subfield thickness (CST) were measured at 2 time points 1 year apart. Rate of change per year was calculated. Generalized estimating equations analyzed associations between rate of change of imaging parameters and PD.Result74 eyes of 40 patients with PD (60% male, mean age 67.47.9 years) & 149 eyes of 78 controls (28% male, mean age 70.35.8 years) were included. No demographic differences were observed between groups except higher proportion of females in controls (p = 0.001). PD had a greater decline in PFD in 6×6 circle (mean change per year = 0.021, control = 0.00, p = 0.001), 6×6 inner ring (PD = 0.018, control = 0.001, p = .007), 6×6 outer ring (PD = 0.022, control = 0.00, p = 0.001), 3×3 circle (PD = 0.016, control = 0.002, p<.001), 3×3 inner ring (PD = 0.016, control = 0.002, p<0.001). PD had greater decline in VD in 6×6 circle (mean change per year in PD = 0.72/mm, control = 0.054/mm, p = 0.006), 6×6 inner ring (PD = 0.636/mm, control = 0.048/mm, p = 0.03), 6×6 outer ring (PD = 0.746/mm, control = 0.054/mm, p = 0.005), 3×3 circle (PD = 0.939/mm, control = 0.006/mm, p<0.001), 3×3 inner ring (PD = ‐0.942/mm, control = 0.013/mm, p<0.001). PD had greater decrease in GCIPL (mean change per year in PD = 0.403µm, control = 0.128µm control, p = 0.01). There were no significant differences in rate of change in FAZ area, RNFL thickness, CST, and no significant differences in rate of change when stratified by PD severity.ConclusionPD may be associated with more rapid loss of retinal microvascular perfusion and vessel densities and more rapid thinning of GCIPL compared to normal aging in controls with normal cognition.

A novel hybrid auxetic honeycomb with enhanced load-bearing and energy absorption properties

Auxetic structures with negative Poisson's ratio exhibit excellent performance in cushioning, shear resistance and energy absorption, but their load-bearing capacity is usually poor. To address this drawback of the conventional Auxetic structure, a star-rhombic honeycomb (SRH) design is proposed in this paper to improve its load-bearing capacity. Analytical models of the elastic modulus and Poisson's ratio of this structure for different loading directions are developed. Quasi-static compression experiments were conducted on SRH specimens fabricated by selective laser melting (SLM) technique. Good agreement was achieved between the simulated and experimental stress response curves and deformation patterns. It was found that the SRH structure possessed better elastic modulus and energy absorption capacity than the SH structure without sacrificing the auxetic properties. The elastic modulus and Poisson's ratio of SRH under the x loading direction are more sensitive to the changes of structural parameters. An optimum energy absorption performance is achieved for an appropriate ratio of the inner rhombic strut thickness to outer reentrant strut thickness (k = 0.5). The specific energy absorption of SRH is improved by 136% and 75% compared to that of the conventional reentrant honeycomb (RH) and star honeycomb (SH), respectively. It has advantages for application scenarios with requirements for both auxetic and load bearing properties.

Insights into photo-induced excited state behaviors for 2-[4-(Di-tert-butyl-amino)-phenyl]-5-(5-fluoro-benzooxazol-2-yl)-benzofuran-6-ol: Solvent effects

Inspired by distinguished white emitters characteristics and potential fluorescence probe performance, we mainly focus on exploring photo-induced behaviors of 2-[4-(Di-tert-butyl-amino)-phenyl]-5-(5-fluoro-benzooxazol-2-yl)-benzofuran-6-ol (DPFB) fluorophore. By comparing changes of chemical structure parameters and variations of infrared (IR) spectrum, we confirm hydrogen bond should be strengthened after photoexcitation. Combined with charge recombination caused by photoexcitation in different solvents, we propose nonpolar solvents are favorable to excited-state dynamic behavior. By searching transition state (TS) form along with excited state reaction path as well as constructing energy profiles, we clearly reveal the solvent polarity dependent excited state intramolecular proton transfer (ESIPT) mechanism for DPFB fluorophore.

Influence of structural parameters of electro-hydraulic diesel fuel injector on set of diagnostic parameters

Introduction. Malfunctions of the elements of the fuel injection system lead to a deterioration in the performance of diesel engines. The largest proportion of faults that occur during the operation of battery injection systems are electro-hydraulic injectors. For the timely detection of malfunctions, the injectors are diagnosed. The most accurate determination of the technical condition of the injectors can be made using specialized diagnostic stands with their removal from the engine. As a rule, the diagnosis is a conclusion about the general technical condition of the injector. To ensure high quality and reduce the complexity of repairs, it is necessary to use new methods and tools that allow for in-depth diagnostics of injectors with the identification of specific defects. The purpose of the presented work is to identify possible differences in the change in the set of diagnostic parameters when changing individual structural parameters in order to be able to determine specific defects in injectors during their diagnosis.Materials and methods. The hydrodynamic processes occurring in the electro-hydraulic injector during its operation were described by a system of differential equations of the first order. Numerical experiments were carried out to study the influence of changes in structural parameters on diagnostic parameters. The calculations using the software environment for mathematical calculations Mathcad were carried out. The calculations at different combinations of pressures in the fuel accumulator and the duration of the control pulse corresponding to certain engine operating modes were carried out.Results. The paper presents the graphs of the dependences of the cyclic supply, the average fuel consumption in the drain line, the delay in the start of the needle lift, the duration of the needle lift and landing, the duration of the injection and the sensitivity of these diagnostic parameters on the gaps in the interfaces ‘needle guide spray body’, ‘plunger multiplier – sleeve’, from the magnitude of the leakage of the control valve.Discussion and conclusion. As a result of numerical experiments, differences in the change in the set of diagnostic parameters with a change in individual structural parameters were found.