Decreasing Layer Thickness Research Articles

Дослідження впливу різних наповнювачів на атмосферостійкість асфальтобетонів

Introduction. The properties of bituminous-mineral materials are determined by the bonds formed between individual mineral grains and depend on the characteristics of the bitumen, the thickness of the bitumen layer covering the mineral grains, as well as the interaction processes between the mineral materials and bitumen at their joint interface. To ensure a strong and stable bond between the grains, the bitumen must evenly cover the surface of the mineral materials with a thin layer. To improve the strength of road pavement made from bituminous-mineral material, it is necessary for the maximum amount of bitumen to be adsorbed by the mineral material, minimizing the content of free bitumen. Problem Statement. Depending on the nature of the mineral material and the chemical composition of the bitumen, the properties of its thin layers change in various ways. On an active mineral surface, the strength of the bitumen in a thin layer increases as the thickness decreases, while on an inactive surface, the strength of the bitumen remains largely unchanged with a decrease in layer thickness.

Effects of Stress and Strain on the Optic Nerve Head on the Progression of Glaucoma.

In primary open-angle glaucoma, the rate of retinal nerve fiber layer thickness decrease was negatively correlated with lamina cribrosa strain, which was associated with intraocular pressure and optic nerve head geometric factors. We hypothesized that the biomechanical deformation of the optic nerve head (ONH) contributes to the progression of primary open-angle glaucoma (POAG). This study investigated the biomechanical stress and strain on the ONH in patients with POAG using computer simulations based on finite element analysis (FEA) and analyzed its association with disease progression. We conducted a retrospective analysis that included patients diagnosed with early-to-moderate stage POAG. The strains and stresses on the retinal nerve fiber layer (RNFL) surface, prelaminar region, and lamina cribrosa (LC) were calculated using computer simulations based on FEA. The correlations between the rate of RNFL thickness decrease and biomechanical stress and strain were investigated in both the progression and non-progression groups. The study included 71 and 47 patients in the progression and non-progression groups, respectively. In the progression group, the factors exhibiting negative correlations with the RNFL thickness decrease rate included the maximum and mean strain on the LC. In multivariate analysis, the mean strain on the LC was associated with optic disc radius, optic cup deepening, axial length, and mean intraocular pressure (IOP), whereas the maximum strain was only associated with mean IOP. In early-to-moderate stage POAG, the rate of RNFL thickness decrease was influenced by both the mean and maximum strain on the LC. Strains on the LC were associated with mean IOP, optic disc radius, axial length, and optic cup deepening. These results suggest that not only IOP but also ONH geometric factors are important in the progression of glaucoma.

High-strength aluminum alloy processed by micro laser powder bed fusion (μ-LPBF): Coordination of laser formability, microstructure evolution, and mechanical properties

As the scale of additive manufacturing process (e.g., laser spot size, powder particle size, powder layer thickness) decreases, the application of micro laser powder bed fusion (μ-LPBF) involves novel mechanisms for process, microstructure and performance coordination. This study provides a systematic view of the processing window and performance enhancement of high-strength Al-Mg-Sc-Zr alloy fabricated by μ-LPBF. The effects of μ-LPBF parameters on defect control and densification activity of the printed parts were analyzed, so as to obtain the suitable processing window. The influence of building orientation and heat treatment on microstructural characteristics and mechanical properties of μ-LPBF processed parts was studied. The μ-LPBF Al-Mg-Sc-Zr exhibited sound surface quality (Ra of 6.088 μm) and considerably refined grains with an average size of 1.102 μm, which was related to the high cooling rate (8.6 × 107 K/s) induced by a small-sized laser beam (25 μm) and a tiny powder particle size distribution (2–20 μm) applied in μ-LPBF. After aging treatment (325 °C/4 h), the superior ultimate tensile strength of 590.24 ± 4.75 MPa combined with the sufficiently high elongation of 11.99 ± 1.17 % was achieved. Due to the significantly decreased scale of μ-LPBF production, the anisotropy caused by the variation of building directions was negligible. These enhanced mechanical properties were attributed to the combined effect of the grain size refinement, the higher number density (1.2 × 1024/mm3) of interior precipitates within grains, and the small-sized molten pool size of μ-LPBF. Computational fluid dynamics (CFD) simulation was applied to reveal the molten pool thermodynamics, indicating that a higher thermal temperature gradient (up to 9.8×107 K/m), a smaller molten pool size (with the width of 38.7–69.8 μm and depth of 8.7–30.0 μm) were generated in μ-LPBF. This work presents great potential in processing high-precision metallic components with fine structural feature size and satisfactory manufacturing quality.

Influence of layer thickness and exposure on mechanical properties of additively manufactured polymer-derived SiOC ceramics

One significant hurdle in additively manufacturing polymer-derived ceramics lies in reconciling the lower mechanical properties of additively manufactured parts compared to traditionally manufactured ceramics and PDCs. Here, a methodology is presented for evaluating the influence of layer thickness and exposure on polymer-derived ceramics within the constraints of commercially available software and hardware. Maximizing exposure within printable limitation of DLP processes, produced green bodies with the highest conversion, and resulted in improved pyrolysis outcomes, manufacturability, and most importantly ceramic strengths comparable to traditionally manufactured SiOC PDCs. Decreasing layer thickness and increasing total dwell time had a dramatic impact on mechanical properties, increasing flexural strength by more than 6x from 18 MPa at 100 μm layer thickness to 111 MPa at 10 μm layer thickness. Density of resultant ceramic also increased from 1.62 ± 0.03 g/cc to 2.3 ± 0.05 g/cc. This represented a large increase in mechanical strengths of PDCs produced via DLP in literature.

Numerical investigation of the bearing performance of Thin- and Thick-Ply hybrid laminates

This publication presents a numerical investigation of Thin-Ply Hybrid CFRP bolted joints. In addition to Thin- and Thick-Ply specimens, hybrid specimens are investigated by substituting a part of the 90° CFRP layers with stainless steel foils. The numerical investigations are based on preliminary experimental work, which showed that fibre kinking led to final failure. A modelling strategy that includes 3D stress states and fibre kinking is chosen. The influence of micro-damages such as matrix cracks decreases with decreasing layer thickness. Therefore, and to avoid high computational power, primarily micro-damages such as matrix cracks are not included. The results of the simulations of the Thin-Ply and the hybrid samples show a good agreement with the experimental results. By hybridisation, the bearing performance can be significantly increased. It is shown that the modelling approach of not including micro-damage is well applicable for thinner plies but reaches its limits for thicker plies.

Effects of highly-textured and untextured polycrystalline layers on deformation mechanisms in amorphous submicron-layered materials

Amorphous alloys have high strength, but softening can lead to room temperature brittleness, limiting their applications. Typically, soft means low hardness and yield strength, and the lower the yield stress, the higher the fracture toughness. Two amorphous/crystalline multilayer samples with submicron single layer thickness were prepared. The crystalline layer of one sample is composed of highly-textured (111) nanocrystalline grains, and the other sample is untextured. Indentation experiments proved that the samples were plastically deformed, while the amorphous layer did not form shear bands with decreased layer thickness. The thickness reduction of the amorphous layer in the sample with highly-textured crystalline layers is greater than in the sample with untextured crystalline layers. The strain-hardening ability of the textured crystalline layer is higher, while the corresponding amorphous layer is deformed more severely with free volume annihilation and greater flow with more compact atoms. The amorphous layer corresponding to the untextured crystalline layer absorbs dislocations, and activates shear transformation zones (STZs), increasing the free volume near the interface. The annihilation of the free volume is less than the sample with highly-textured crystalline layers.

Evaluation of macular vessel density among patients with glaucoma, ocular hypertension, and normal participants

Purpose To assess macular vessel density (VD) in open-angle glaucoma (OAG), normal tension glaucoma (NTG), ocular hypertension (OHT), and normal participants by using optical coherence tomography angiography (OCTA). Setting and design This observational case–control study was conducted at Menoufia University, Faculty of Medicine, Department of Ophthalmology. Patients and methods Patients who received OCTA were already diagnosed with glaucoma and were divided into four groups: OAG group, NTG group, OHT group, and normal participants’ group. The ophthalmic parameters, which include best-corrected visual acuity, intraocular pressure, visual field mean deviation, retinal nerve fiber layer thickness, and ganglion cell complex thickness, were recorded. About the macula, the superficial VD, deep VD, and foveal avascular zone (FAZ) were evaluated via OCTA and analyzed by utilizing the default VD analysis program in the same OCTA. Results This study was conducted on 152 eyes, 38 eyes with OAG, 38 eyes with NTG, 38 eyes with OHT, and 38 normal participant eyes. Significant decrease in retinal nerve fiber layer thickness and ganglion cell complex thickness were noticed in OAG and normal tension groups cases. The OAG and NTG groups revealed a reduction in superficial VD and a reduction in deep VD compared to the OHT and the controls. No difference in the FAZ was noticed among all the studied groups. Conclusion Impaired macular circulation was demonstrated in the OAG and NTG patients compared to OHT patients and normal participants. No difference in FAZ among the glaucoma cases and normal individuals.

Interfacial Distortion of Sb2Te3-Sb2Se3 Multilayers via Atomic Layer Deposition for Enhanced Thermoelectric Properties.

Atomic layer deposition (ALD) is an effective technique for depositing thin films with precise control of layer thickness and functional properties. In this work, Sb2Te3-Sb2Se3 nanostructures were synthesized using thermal ALD. A decrease in the Sb2Te3 layer thickness led to the emergence of distinct peaks from the Laue rings, indicative of a highly textured film structure with optimized crystallinity. Density functional theory simulations revealed that carrier redistribution occurs at the interface to establish charge equilibrium. By carefully optimizing the layer thicknesses, we achieved an obvious enhancement in the Seebeck coefficient, reaching a peak figure of merit (zT) value of 0.38 at room temperature. These investigations not only provide strong evidence for the potential of ALD manipulation to improve the electrical performance of metal chalcogenides but also offer valuable insights into achieving high performance in two-dimensional materials.

Ocular blood flow biomarkers may predict long-term glaucoma progression

Background/aimTo examine the relationship between baseline blood flow biomarkers and long-term open-angle glaucoma (OAG) progression.Methods112 patients with early to moderate OAG (mean age 64.9±11.0 years; 68 female) were evaluated at...

Characterizing pearlite transformation in an API X60 pipeline steel through phase-field modeling and experimental validation

This study explores the microstructural characterization of pearlite phase transformation in high-strength low-alloy API X60 steel, which is used in pipelines. Understanding the formation, phase percentages, and morphology of the pearlitic phase is crucial since it affects the mechanical properties of the considered steel. In this research, a phase-field model, particularly the Cahn–Hilliard approach, was used in order to simulate the formation and morphology of the pearlite phase in response to different heat treatments. Both double- and triple-well potentials were considered for comprehensively studying pearlite’s morphology in the simulations. The simulation results were then compared with experimental outcomes obtained by metallography and field-emission scanning electron microscopy analyses. Considering the double-well potential can help simulate only two phases, ferrite and cementite, which is less compatible with the experiment results than the triple-well potential, which gives the possibility of simulating a three-phase microstructure, ferrite, cementite, and austenite, and a better match with experimental data. The study revealed that as the cooling rate increases, the interlamellar spacing and layer thickness decrease. Additionally, the difference between experimental and simulation results using triple-well potential was approximately ∼10%. Therefore, triple-well potential formulation predictions have better agreements with experimental results for the development circumstance of pearlitic structures.

Two Cases of Ischemic Optic Neuropathy after Extracorporeal Membrane Oxygenation (ECMO)

Purpose: We report two cases of non-arteritic ischemic optic neuropathy (NAION) following extracorporeal membrane oxygenation (ECMO) treatment.Case summary: (Case 1) A 36-year-old man underwent ECMO treatment. Upon regaining consciousness, he complained of a darkened peripheral visual field and was subsequently referred to an ophthalmologist. His best-corrected visual acuity was 0.9 in the right eye and 0.8 in the left eye. The intraocular pressure measured 12 mmHg in the right eye and 10 mmHg in the left eye; color vision was normal. A visual field test demonstrated concentric visual field defects in both eyes, and a fundus examination revealed a pale optic disc. Optical coherence tomography (OCT) indicated a decrease in retinal nerve fiber layer (RNFL) thickness. (Case 2) A 48-year-old woman underwent ECMO treatment. After regaining consciousness, she reported decreased vision in her right eye. Her best-corrected visual acuity was limited to hand motion in the right eye and was 1.2 in the left eye. A relative afferent pupillary defect in the right eye was observed. Color vision in the right eye was compromised, and a fundus examination revealed a pale optic disc. A visual field test demonstrated total visual field defect in the right eye, while OCT showed decreases in both the RNFL thickness and the ganglion cell-inner plexiform layer thickness of the right eye. Magnetic resonance imaging (MRI) revealed high signal intensity and abnormal enhancement in the right retrobulbar optic nerve.Conclusions: In cases where vision loss and visual field defects are observed following ECMO treatment, differential diagnoses for ischemic optic neuropathy are warranted.

Microstructure and Mechanical Properties of Mg-Li/Al Dissimilar Joints via Dynamic Support Friction Stir Lap Welding.

In this study, two-mm-thick dual-phase LA103Z Mg-Li and 6061 Al alloys, known for their application in lightweight structural designs, were joined using dynamic support friction stir lap welding (DSFSLW). The microstructural evolution and mechanical properties of dissimilar joints were investigated at different welding speeds. The analysis revealed two distinct interfaces: the diffusion interface and the mixed interface. The diffusion interface, characterized by a pronounced diffusion zone, is formed under slower welding speeds. The diffusion zone height, the effective lap width, and the interface layer thickness decrease with increasing welding speed due to low plastic deformation capacity and weak interfacial reactions. Conversely, the mixed interface, associated with higher welding speeds, contained large Al fragments. The extremely high microhardness values (130.5 HV) can be ascribed to the formation of intermetallic compounds (IMCs) and strain-hardened Al fragments. Notably, the maximum shear strength achieved was 175 N/mm at a welding speed of 20 mm/min. The fracture behavior varied significantly with the interface type; the diffusion interface showed enhanced mechanical strength due to better intermetallic reactions and interlocking structures, while the mixed interface displayed more linear crack propagation due to weaker IMCs and the absence of hook structures. Fracture surface analysis indicates that fractures are more likely to propagate through the Al matrix and interface layers.

The effect of printing parameters on the properties of 17-4 PH stainless steel fabricated by material extrusion additive manufacturing

The 17-4PH stainless steel filament was characterised and utilised to study the effect of printing parameters, i.e. printing temperature, layer thickness, infill pattern and extrusion multiplier on the physical properties. The as-printed and as-sintered internal structures were analysed. The results showed that the as-printed density increases with increasing printing temperature and extrusion multiplier and decreasing layer thickness. The use of the line infill pattern also provided slightly higher as-printed density than the concentric infill pattern due to the low fraction of void between deposited paths. After sintering, the trace of these voids can be observed together with smaller-size residual pores from the spaces between powders, which is the nature of the pressureless sintering process. The microstructure of the as-sintered specimens was similar to the typical microstructure of the 17-4PH alloy fabricated by metal injection moulding process, which contains delta ferrite, martensite and Si-rich phases. In additions, the internal void generated during debinding and sintering results in unexpectedly low tensile properties and results in the difference in tensile properties between the concentric and line infill patterns.

Evaluation of the Surface Integrity and Recast Layer in Electrical Discharge Turning of WC-Co Composites.

Tungsten carbide (WC) and its composites are typically associated with high hardness and high wear resistance, posing challenges in conventional machining processes like turning. To address the machining difficulties of WC-Co, electrical discharge turning (EDT) was proposed. The rotational speed in EDT is a key factor influencing the machining results; however, conflicting reports exist about its impact on the EDT process. Therefore, the effect of rotational speed on three different machining regimes, including roughing, semi-finishing, and finishing, was investigated using energy-dispersive X-ray spectroscopy (EDX), SEM, and roughness tests. Additionally, elemental mapping was applied to illustrate the element distribution on the machined surface. The results indicated that increasing the rotational speed led to a 10% to 17% decrease in the recast layer thickness and a 14% to 54% reduction in the surface roughness (Ra).

Retinal Structural and Vascular Changes in Patients with Coronary Artery Disease: A Systematic Review and Meta-Analysis.

Retinal microvascular anomalies have been identified in patients with cardiovascular conditions such as arterial hypertension, diabetes mellitus, and carotid artery disease. We conducted a systematic review and meta-analysis (PROSPERO registration number CRD42024506589) to explore the potential of retinal vasculature as a biomarker for diagnosis and monitoring of patients with coronary artery disease (CAD) through optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). We systematically examined original articles in the Pubmed, Embase, and Web of Science databases from their inception up to November 2023, comparing retinal microvascular features between patients with CAD and control groups. Studies were included if they reported sample mean with standard deviation or median with range and/or interquartile range (which were computed into mean and standard deviation). Review Manager 5.4 (The Cochrane Collaboration, 2020) software was used to calculate the pooled effect size with weighted mean difference and 95% confidence intervals (CI) by random-effects inverse variance method. Eleven studies meeting the inclusion criteria were incorporated into the meta-analysis. The findings indicated a significant decrease in the retinal nerve fiber layer (WMD -3.11 [-6.06, -0.16]), subfoveal choroid (WMD -58.79 [-64.65, -52.93]), and overall retinal thickness (WMD -4.61 [-7.05, -2.17]) among patients with CAD compared to controls (p < 0.05). Furthermore, vascular macular density was notably lower in CAD patients, particularly in the superficial capillary plexus (foveal vessel density WMD -2.19 [-3.02, -1.135], p < 0.0001). Additionally, the foveal avascular zone area was statistically larger in CAD patients compared to the control group (WMD 52.73 [8.79, 96.67], p = 0.02). Heterogeneity was significant (I2 > 50%) for most features except for subfoveal choroid thickness, retina thickness, and superficial foveal vessel density. The current meta-analysis suggests that retinal vascularization could function as a noninvasive biomarker, providing additional insights beyond standard routine examinations for assessing dysfunction in coronary arteries.

Postcumulus Processes Recorded in Whole-Rock Geochemistry: a Case Study from the Mirabela Layered Intrusion, Brazil

Abstract According to the ‘trapped liquid’ paradigm, whole-rock chemical compositions of cumulate rocks in layered intrusions can be represented as closed-system multicomponent mixtures of the cumulus phases and the liquids from which they crystallised. Alternative open-system models for cumulate solidification assert that intercumulus liquid is continuously mobile as a result of compaction of crystal mushes. In the closed-system models, all excluded elements, i.e. those incompatible in the cumulus phases, should be correlated with one another, whereas in open systems the more incompatible elements should be decoupled from the more compatible ones and correlations should be poor. These alternative hypotheses are tested using a database of &amp;gt;63 000 whole-rock analyses of mostly ultramafic cumulates from a single package of layers across the entire width of the Mirabela layered intrusion, a 2.5-km-wide by &amp;gt;2-km-thick intrusion with Great Dyke-like stratigraphy. Variably compatible elements Al, Na, Ti and P are found to show strong correlations with one other in olivine-pyroxene cumulates across the spectrum from mesocumulate to orthocumulate rocks, where drill-core sample intervals are composited over 3 m; weaker correlations are found over 1-m sample intervals. The closed-system trapped liquid model is robust for this suite of rocks at the scale of 3-m lengths of drill core (~1 kg of sample). Furthermore, a very smooth and symmetrical variation is observed from dominantly ad- to mesocumulate rocks in the geometrical centre of the intrusion towards orthocumulates at both margins, attributable to increase in cooling rate towards the margins. The most adcumulate rocks are gabbronorites at the base of the mafic sequence in the centre of the intrusion. There is no corresponding decrease in layer thickness towards the centre that would be predicted by a compaction model. The only incompatible element showing partial decoupling is K, which appears to have been mobile at a very late stage, probably in an aqueous fluid phase. There is no evidence for mobilisation of platinum group elements or other chalcophile elements by this fluid despite the presence of disseminated sulfide throughout the sampled interval.

The influence of filler and FDM printing parameters on the strength of PLA

The tensile strength of samples made by FDM technology from PLA and PLA with different fillers (aluminum oxide, copper, carbon fiber) was investigated. FDM process parameters (raster angle, layer thickness and number of shells) were optimized using ANOVA test. It was found that the raster angle is the most influential parameter. Tensile strength increases as the raster angle increases and the number of shells as well as layer thickness (larger number of infills) decreases. The highest strength was achieved for PLA/PLA-Al2O3.

Ripa-56 protects retinal ganglion cells in glutamate-induced retinal excitotoxic model of glaucoma

Glaucoma is a prevalent cause of blindness globally, characterized by the progressive degeneration of retinal ganglion cells (RGCs). Among various factors, glutamate excitotoxicity stands out as a significant contributor of RGCs loss in glaucoma. Our study focused on Ripa-56 and its protective effect against NMDA-induced retinal damage in mice, aiming to delve into the potential underlying mechanism. The R28 cells were categorized into four groups: glutamate (Glu), Glu + Ripa-56, Ripa-56 and Control group. After 24 h of treatment, cell death was assessed by PI / Hoechst staining. Mitochondrial membrane potential changes, apoptosis and reactive oxygen species (ROS) production were analyzed using flow cytometry. The alterations in the expression of RIP-1, p-MLKL, Bcl-2, BAX, Caspase-3, Gpx4 and SLC7A11 were examined using western blot analysis. C57BL/6j mice were randomly divided into NMDA, NMDA + Ripa-56, Ripa-56 and control groups. Histological changes in the retina were evaluated using hematoxylin and eosin (H&E) staining. RGCs survival and the protein expression changes of RIP-1, Caspase-3, Bcl-2, Gpx4 and SLC7A11 were observed using immunofluorescence. Ripa-56 exhibited a significant reduction in the levels of RIP-1, p-MLKL, Caspase-3, and BAX induced by glutamate, while promoting the expression of Bcl-2, Gpx-4, and SLC7A1 in the Ripa-56-treated group. In our study, using an NMDA-induced normal tension glaucoma mice model, we employed immunofluorescence and H&E staining to observe that Ripa-56 treatment effectively ameliorated retinal ganglion cell loss, mitigating the decrease in retinal ganglion cell layer and bipolar cell layer thickness caused by NMDA. In this study, we have observed that Ripa-56 possesses remarkable anti- necroptotic, anti-apoptotic and anti-ferroptosis properties. It demonstrates the ability to combat not only glutamate-induced excitotoxicity in R28 cells, but also NMDA-induced retinal excitotoxicity in mice. Therefore, Ripa-56 could be used as a potential retinal protective agent.

Influence of thermal loading parameters and microstructure on the formation of stratified surface layers on railway wheels

Due to an increasing trend towards environmentally friendly public transport, rail networks face higher speeds and wheel loads affecting the material degradation of the railway components. Within this study, influencing parameters on the formation of stratified surface layers, forming on railway wheels during service due to thermal loadings in the wheel-rail contact, are studied. These layers consist of white etching layer and underlying brown etching layer and are susceptible to fatigue crack initiation. By using laser surface treatments, its formation based on two consecutive thermal loadings is systematically demonstrated on ER7 wheel steel. Further, a decrease in layer thickness with decreasing laser power, and an increase in brown etching layer thickness with increasing laser power difference is shown. Moreover, the effect of finer grain size leading to an increased layer thickness, and the influence of the chemical composition by comparing the standard ER7 wheel steel to a micro-alloyed wheel steel are demonstrated.

Hot-Electron Microwave Noise and Energy Relaxation in (Be)MgZnO/ZnO Heterostructures

Pulsed hot-electron microwave noise measurements of the (Be)MgZnO/ZnO heterostructures are presented in this work. The heterostructures of different barrier thicknesses and different bulk electron densities in ZnO layer are compared. Capacitance–voltage (C–V) measurements reveal the decrease in the two-dimensional electron gas (2DEG) peak in electron density profile at the Zn-polar BeMgZnO/ZnO interface as the BeMgZnO barrier layer thickness decreases. For thin-barrier heterostructures, the peak disappears and only the bulk electron density is resolved in C–V measurements. The excess noise temperature at ∼10 GHz in thick-barrier heterostructures is noticeably higher (∼10 times) compared to thin-barrier heterostructures, which is attributed to the strong noise source in the contacts of the former. In the case of thin-barrier heterostructures, at electric fields above ∼10 kV/cm and electron density ≳1×1017cm−3, strong noise source is resolved, which was also observed earlier in the Ga-doped ZnO films due to the formation of self-supporting high-field domains. However, for the low electron densities (≲6 ×1016 cm−3), the aforementioned noise source is not observed, which suggests the importance of a deep ZnO/GaN interface with 2DEG for power dissipation. The hot-electron temperature dependence on the dissipated power of those low-electron-density heterostructures is similar to that of O-polar ZnO/MgZnO. The estimated electron energy relaxation time in ZnO/MgZnO is ∼0.45 ps ± 0.05 ps at dissipated electrical power per electron of ∼0.1 nW/el and approaches ∼0.1 ps as the dissipated power is increased above ∼10 nW/el.