Local Thickness Changes Research Articles

Near-Field Photoluminescence of WS<sub>2</sub> and MoS<sub>2</sub> Monolayers, Grown by Chemical Vapor Deposition

Monolayer triangular WS2 and MoS2 islands grown by chemical vapor deposition was investigated by near-field photoluminescence (nano-PL) enhanced by the metallized atomic force microscope (AFM) tip. To achieve maximum near-field response from WS2 and MoS2 materials fabricated Au and Ag metallized AFM tips were used. Maximum nano-PL responds from the islands is observed under the resonant conditions when the energy of the localized surface plasmon of the metallized probe coincides with the energy of the exciton luminescence of the WS2 and MoS2 materials. Nano-PL mapping of the exciton response allows visualizing structural defects and determine the local thickness changes of monolayer islands with nanometer spatial resolution.

The effect of menisci on vortex streets on soap film flows

In soap film experiments, the insertion of an external object is necessary to produce vorticity. However, this insertion causes local thickness changes, or simply meniscus, near the object. Because the meniscus formation may alter the flow near the object, the characterization of a meniscus is of considerable importance for the accurate interpretation of data. In this study, we insert cylindrical cones made of aluminum, titanium, and glass to measure the size of the menisci by using a long-range microscope. In all material tested, we find that the size of the meniscus is less than 0.2 mm, much shorter than the capillary length. In addition, by comparing the formation of vortex streets behind objects of different materials, we conclude that the meniscus acts as an added length to the size of the object itself. This added length effect can be non-negligible if the size of an object is comparable to the size of a meniscus.

Detecting Subclinical Corneal Edema Using Corneal Thickness Mapping in Patients Presenting Fuchs Endothelial Corneal Dystrophy

To determine whether local corneal thickness changes observed with optical coherence tomography (OCT) can detect subclinical corneal edema in Fuchs endothelial corneal dystrophy (FECD). Retrospective cohort study. A series of patients presenting FECD who underwent cataract surgery alone (45 eyes) or with concomitant Descemet membrane endothelial keratoplasty (triple procedure; 117 eyes). The study reviewed medical records, collected the preoperative corneal thickness map and calculated the differences and ratio of corneal thickness measured at 5, 7, and 9 mm from the central corneal thickness. Area under the receiver operating characteristic curves (AUCs) were calculated and thresholds were selected to obtain a specificity of 90%. The median difference between 5- and 2-mm corneal thickness in the supra-nasal quadrant (∆5-2mmSN) was 38 µm (interquartile range 34-46) in the cataract group and 17 µm (2-38) in the triple procedure group (P < .001). The corneal thickness ratios of supra-nasal 5- to 2-mm (R5/2mmSN) and 7- to 2-mm (R7/2mmSN) were 1.07 (1.06-1.08) and 1.15 (1.13-1.17)] in the cataract group and 1.03 (1.00-1.06) and 1.09 (1.06-1.14) in the triple procedure group (P < .001). The probability of corneal edema was increased 7-fold with ∆5-2mm SN < 27 µm (AUC=0.76) and 9.4- and 7.4-fold with R5/2mmSN and R7/2mmSN < 1.045 (AUC=0.77) and 1.118 (AUC=0.76), respectively. Local changes in corneal thickness may be useful in detecting preclinical corneal edema, especially in patients with FECD undergoing cataract surgery.

Real-Time Nondestructive Evaluation of Additive Manufacturing Using a Laser Vibrometer and Shock Tube

Abstract Additive manufacturing (AM) parts retain a certain degree of individuality and could suffer from a combination of different defect types, and therefore the nondestructive evaluation on AM parts remains a challenging task. Engineering non-contact and nondestructive real-time inspection and in situ quality assurance of AM parts would be a net improvement compared to current quality control methods that are conducted post-production. Here, the authors propose to combine the use of a laser vibrometer with a compression-driven shock tube to assess the quality of AM parts through the evaluation of the vibration spectra of the part. An AM of a cylindrical part was selected for the study, along with different defect types and sizes. These defects include internal voids of different sizes at different locations, local changes in thickness (infill), and local changes in melting temperatures. A numerical model was created and validated using experimental data to conduct model-assisted probability of detection (MAPOD). Results were analyzed by evaluating correlation matrices between different models. Results showed that vibration spectra induced by a shock wave were sensitive to different types and sizes of defects under the studied geometry. The defect index yielded an approximately linear relationship with respect to defect void severity. MAPOD curve studies revealed a minimum detectable void defect of 0.039% of the AM part’s volume.

Data-driven Normative Reference of Pediatric Cranial Bone Development.

Background:Available normative references of cranial bone development and suture fusion are incomplete or based on simplified assumptions due to the lack of large datasets. We present a fully data-driven normative model that represents the age- and sex-specific variability of bone shape, thickness, and density between birth and 10 years of age at every location of the calvaria.Methods:The model was built using a cross-sectional and multi-institutional pediatric computed tomography image dataset with 2068 subjects without cranial pathology (age 0–10 years). We combined principal component analysis and temporal regression to build a statistical model of cranial bone development at every location of the calvaria. We studied the influences of sex on cranial bone growth, and our bone density model allowed quantifying for the first time suture fusion as a continuous temporal process. We evaluated the predictive accuracy of our model using an independent longitudinal image dataset of 51 subjects.Results:Our model achieved temporal predictive errors of 2.98 ± 0.69 mm, 0.27 ± 0.29 mm, and 76.72 ± 91.50 HU in cranial bone shape, thickness, and mineral density changes, respectively. Significant sex differences were found in intracranial volume and bone surface areas (P < 0.01). No significant differences were found in cephalic index, bone thickness, mineral density, or suture fusion.Conclusions:We presented the first pediatric age- and sex-specific statistical reference for local cranial bone shape, thickness, and mineral density changes. We showed its predictive accuracy using an independent longitudinal dataset, we studied developmental differences associated with sex, and we quantified suture fusion as a continuous process.

State-of-Charge Dependent Change of the Young’s Modulus in Lithium-Ion Batteries

One way to increase the sustainability of lithium-ion batteries (LIB) is to extend the cycle life, e.g., in electric vehicles. To do this, the effects within a LIB must be understood and tracked over its lifetime. In addition to electrical (e.g. IR-drop) and thermal measurements (e.g. temperature inhomogeneities), a new approach for such studies is the use of ultrasound to investigate the mechanical changes inside a LIB [1]. With this low-cost technology, it is possible to detect mechanical degradation (e.g. local thickness change due to lithium plating) or Young’s moduli changes over lifetime and possibly counteract them by the battery management system.In this work a self-built device containing a LIB between two opposing transducers is used to study the impact of state-of-charge (SOC), current rate and frequency on the ultrasound signal inside the LIB. Based on the time the ultrasound signal takes to pass through the LIB (time-of-flight (TOF)), the speed of sound and the Young’s moduli can be determined. The influence of the applied current rate and the frequency of the transducer to the TOF/ speed of sound in the LIB is relatively small. However, the SOC has an impact on the TOF/ speed of sound, where the speed of sound is around 4.5% higher in the fully charged state with ~1740 m s-1 compared to the discharged state with ~1660 m s-1 (see Figure 1 (a)). One explanation for this phenomenon is the change in the lithium staging within the graphite anode. In a charged battery, the graphite anode is filled with lithium ions, which enhances the transmission properties of ultrasound. By knowing speed of sound, the Young’s modulus of the whole battery can be estimated as ~4.2 GPa in discharged state and ~5.6 GPa in the charged state (Figure 1 (b)). This significant increase can also be explained with the lithiation stages of the graphite anode, as the graphite particles themselves exhibit a threefold increase of the Young’s modulus during lithiation [2]. Additionally, the evolution of the speed of sound and Young’s moduli is studied during aging of the LIB.

Cortical Thickness Adaptive Response to Mechanical Loading Depends on Periosteal Position and Varies Linearly With Loading Magnitude.

The aim of the current study was to quantify the local effect of mechanical loading on cortical bone formation response at the periosteal surface using previously obtained μCT data from a mouse tibia mechanical loading study. A novel image analysis algorithm was developed to quantify local cortical thickness changes (ΔCt.Th) along the periosteal surface due to different peak loads (0N ≤ F ≤ 12N) applied to right-neurectomised mature female C57BL/6 mice. Furthermore, beam analysis was performed to analyse the local strain distribution including regions of tensile, compressive, and low strain magnitudes. Student’s paired t-test showed that ΔCt.Th in the proximal (25%), proximal/middle (37%), and middle (50%) cross-sections (along the z-axis of tibia) is strongly associated with the peak applied loads. These changes are significant in a majority of periosteal positions, in particular those experiencing high compressive or tensile strains. No association between F and ΔCt.Th was found in regions around the neutral axis. For the most distal cross-section (75%), the association of loading magnitude and ΔCt.Th was not as pronounced as the more proximal cross-sections. Also, bone formation responses along the periosteum did not occur in regions of highest compressive and tensile strains predicted by beam theory. This could be due to complex experimental loading conditions which were not explicitly accounted for in the mechanical analysis. Our results show that the bone formation response depends on the load magnitude and the periosteal position. Bone resorption due to the neurectomy of the loaded tibia occurs throughout the entire cross-sectional region for all investigated cortical sections 25, 37, 50, and 75%. For peak applied loads higher than 4 N, compressive and tensile regions show bone formation; however, regions around the neutral axis show constant resorption. The 50% cross-section showed the most regular ΔCt.Th response with increased loading when compared to 25 and 37% cross-sections. Relative thickness gains of approximately 70, 60, and 55% were observed for F = 12 N in the 25, 37, and 50% cross-sections. ΔCt.Th at selected points of the periosteum follow a linear response with increased peak load; no lazy zone was observed at these positions.

2Pb5-8 Optimization of Window Length in Velocity Estimation in Heart Wall Using Ultrasound Phase Difference for Measurement of Local Change in Myocardial Layer Thickness

2Pb5-8 Optimization of Window Length in Velocity Estimation in Heart Wall Using Ultrasound Phase Difference for Measurement of Local Change in Myocardial Layer Thickness

Morphological Heterogeneities of Stripped and Plated Lithium Metal Analyzed By X-Ray Tomography

Lithium (Li) metal is the most promising anode battery material to be implemented in stationary and electric vehicle applications [1]. For years, its use and subsequent industrialization was hampered because of the inhomogeneous Li electrodeposits onto Li metal leading to dendrite growth [2]. The use of solid polymer electrolyte is a solution to mitigate dendrite growth but the Li redox processes, stripping and plating, remain heterogeneous. Blue Solutions compagny is already commercializing lithium metal batteries using a solid polymer electrolyte to prevent dendrite growth. A precise characterization of the behaviour of these heterogeneities during cycling is essential to move towards an optimized anode. During our research, we have developed a characterization method based on X-ray tomography applied to model Li symmetric cells toquantify and spatially probe the Li stripping/plating process. Ante- and post-mortem cells are recut in order to allow a 1µm voxel sizein a conventional laboratory scanner. The reconstructed cell volume is post-processed to numerically re-flatten the Li electrodes, allowingus a subsequent precise measurement of the electrode and electrolyte thicknesses and revealing local interface modifications. This in-depthanalysis brings information on the location of heterogeneities and the impact on the electrode microstructure both at the electrode grains andgrain boundaries. This simple methodology permits to finely retrieve and then surface-map the local current density at both electrodes basedon the local thickness change during the redox process (see Figure 1a : 2D map of the cathode local current density variations overlaped withgrain boundaries pattern (image analysis of a cell after moving 22µm of lithium)). Thanks to quantitative data that can be extracted from the2D maps (see Figure 1b: anode and cathode quantitative distribution of local current density variations), we show that the plating process(reduction) induces more pronounced heterogeneous deposits compared to the stripping (oxidation) one. The existence of cross-talkingbetween the electrodes is also highlighted. [1] Wu Xu et al., Energy Environ. Sci. 7, no 2 (2014): 513-37[2] Xin-Bing Cheng et al., Chemical Reviews 117, n°15 (2017): 10403-73 Figure 1

High-temperature effects on the mucus layers in a realistic human upper airway model

Firefighters and workers in some industries often inhale (polluted) air at high temperatures, eg, 50–200°C, and very low relative humidity, say, 5–10%. Such severe environmental conditions may cause health problems or further aggravate existing ones. As in vivo tests are very complex, potentially harmful and costly, and in vitro experiments often lack high resolution and predictive capability, in silico studies become a priority. They may include computer simulations of the air-particle dynamics in human lung-airway models to understand the convection heat transfer as well as pollutant transport, deposition and uptake at high inlet temperatures and low relative humidity. In this study, detailed modeling, simulation and analysis focuses on two-phase flow in a human upper lung-airway model with a realistic 3D mucus lining. Especially modeling of the upper airway mucus layers was of interest in order to simulate the vapor mass transfer to the airflow because of its primary function for airway humidification. Naturally, the humidification causes water loss in the mucus layer, which leads to its reduction or even depletion when exposed to relatively high temperatures. Accounting for the changes in thickness and the rise in temperature in the mucus layer allows for the determination of locations of thermal injury in the human airways due to continuous exposure of such abnormal inhalation conditions. Different temperature profiles and local changes in mucus layer thickness were studied for ranges of severe inlet temperature conditions at a representative flow rate of 20 LPM (liters per minute). For inlet temperature reaching 100°C, mucus-layer thinning was observed in the upper airways. Interestingly, as a confirmation of the Reynolds analogy, the areas of significant wall heat flux and associated wall shear stress coincided with the regions of highest mucus evaporation, resulting in the humidification of the air with low relative humidity. Model development and mucus layer generation were done using C++ programming. All computer simulations were carried out using the open-source computational fluid dynamics toolbox OpenFOAM.

Quantification of the Local Topological Variations of Stripped and Plated Lithium Metal by X-ray Tomography.

Lithium (Li) metal is the most promising negative electrode to be implemented in batteries for stationary and electric vehicle applications. For years, its use and subsequent industrialization were hampered because of the inhomogeneous Li+ ion reduction upon recharge onto Li metal leading to dendrite growth. The use of solid polymer electrolyte is a solution to mitigate dendrite growth. Li reduction leads typically to dense Li deposits, but the Li stripping and plating process remain nonuniform with local current heterogeneities. A precise characterization of the behavior of these heterogeneities during cycling is then essential to move toward an optimized negative electrode. In this work, we have developed a characterization method based on X-ray tomography applied to model Li symmetric cells to quantify and spatially probe the Li stripping/plating processes. Ante- and post-mortem cells are recut in smaller cells to allow a 1 μm voxel size resolution in a conventional laboratory scanner. The reconstructed cell volume is postprocessed to numerically reflatten the Li electrodes, allowing us a subsequent precise measurement of the electrode and electrolyte thicknesses and revealing local interface modifications. This in-depth analysis brings information about the location of heterogeneities and their impact on the electrode microstructure at both the electrode grains and grain boundaries. We show that the plating process (reduction) induces more pronounced heterogeneities compared to the stripping (oxidation) one. The existence of crosstalking between the electrodes is also highlighted. In addition, this simple methodology permits to finely retrieve and then surface map the local current density at both electrodes based on the local thickness change during the redox process.

Mechanical stimuli for left ventricular growth during pressure overload.

The mechanical stimulus (i.e. stress or stretch) for growth occurring in the pressure-overloaded left ventricle (LV) is not exactly known. To address this issue, we investigate the correlation between local ventricular growth (indexed by local wall thickness) and the local acute changes in mechanical stimuli after aortic banding. LV geometric data were extracted from 3D echo measurements at baseline and 2 weeks in the aortic banding swine model (n = 4). We developed and calibrated animal-specific finite element (FE) model of LV mechanics against pressure and volume waveforms measured at baseline. After the simulation of the acute effects of pressure-overload, the local changes of maximum, mean and minimum myocardial stretches and stresses in three orthogonal material directions (i.e., fiber, sheet and sheet-normal) over a cardiac cycle were quantified. Correlation between mechanical quantities and the corresponding measured local changes in wall thickness was quantified using the Pearson correlation number (PCN) and Spearman rank correlation number (SCN). At 2 weeks after banding, the average septum thickness decreased from 10.6 ± 2.92mm to 9.49 ± 2.02mm, whereas the LV free-wall thickness increased from 8.69 ± 1.64mm to 9.4 ± 1.22mm. The FE results show strong correlation of growth with the changes in maximum fiber stress (PCN = 0.5471, SCN = 0.5111) and changes in the mean sheet-normal stress (PCN= 0.5266, SCN = 0.5256). Myocardial stretches, however, do not have good correlation with growth. These results suggest that fiber stress is the mechanical stimuli for LV growth in pressure-overload.

On the Applicability of Thermoforming Characterization and Simulation Approaches to Glass Mat Thermoplastic Composites

Chopped fiber composite materials offer the potential to be used for complex geometries, including local thickness changes, ribs and beads, offering significant potential for functional lightweighting. Depending on the initial mold coverage and flowability of the material, the processing behaves either more like a compression molding or a thermoforming process. The latter is applicable to high initial mold coverages and includes typical thermoforming defects such as local wrinkling. Such defects are not predictable by conventional compression molding simulation approaches usually adopted for this material class. Therefore, thermoforming characterization and simulation approaches and their applicability to glass mat thermoplastic (47 vol.% long glass fiber, Tepex Flowcore) for high initial mold coverages is investigated. Abaqus in combination with several user-subroutines is applied. Valid material characterization results from torsion bar and rheometer bending tests are obtained and applied to an automotive structure in thermoforming simulation. Results indicate that the high stiffness and high viscosity captured by the rheometer bending test at low shear-rates are necessary to reproduce the wrinkling behavior observed in the experimental results. Discrepancy is most likely reducible to thermomechanical effects, and that the modelling approach does not account for thickness deformation due to transverse compression.

3J4-3 Measurement of local change in myocardial thickness caused by electrical excitation in heart wall

3J4-3 Measurement of local change in myocardial thickness caused by electrical excitation in heart wall

Role of corneal epithelial thickness mapping in the evaluation of keratoconus

PurposeTo investigate the corneal epithelial thickness profiles in patients with a confirmed diagnosis of stable and progressive keratoconus. SettingStudio Italiano di Oftalmologia, Rome, Italy. DesignObservational study. Methods86 patients with either stable (n = 52) or progressive (n = 34) keratoconus and 182 healthy controls were enrolled in the study. Disease progression was confirmed by repeated corneal topographies over 1 year follow-up before inclusion in the study. All subjects had full corneal and epithelial thickness mapping taken by spectral domain optical coherence tomography (SD-OCT). The full corneal mapping was investigated by evaluating the central corneal thickness, the thinnest point, the superonasal-inferotemporal thickness difference and the minimum-median thickness difference. The epithelial mapping was investigated by assessing the 2 mm central thickness, the inferior paracentral (2–5 mm) thickness, and the minimum-maximum thickness difference. ResultsNo significant differences in full corneal mapping were found between stable and progressive keratoconic eyes. Of note, the inferior paracentral region of the corneal epithelium was significantly thinner in progressive (50 ± 3 μm) than stable (53 ± 4 μm) keratoconus (P < 0.001). ConclusionsThe SD-OCT corneal epithelial mapping was valuable for detecting local thickness changes in eyes with keratoconus. Monitoring the corneal epithelial changes across the inferior area in patients with keratoconus could be worthy for assessing disease progression.

Effects of Anterior Cruciate Ligament Deficiency on Tibiofemoral Cartilage Thickness and Strains in Response to Hopping

Background: Changes in knee kinematics after anterior cruciate ligament (ACL) injury may alter loading of the cartilage and thus affect its homeostasis, potentially leading to the development of posttraumatic osteoarthritis. However, there are limited in vivo data to characterize local changes in cartilage thickness and strain in response to dynamic activity among patients with ACL deficiency. Purpose/Hypothesis: The purpose was to compare in vivo tibiofemoral cartilage thickness and cartilage strain resulting from dynamic activity between ACL-deficient and intact contralateral knees. It was hypothesized that ACL-deficient knees would show localized reductions in cartilage thickness and elevated cartilage strains. Study Design: Controlled laboratory study. Methods: Magnetic resonance images were obtained before and after single-legged hopping on injured and uninjured knees among 8 patients with unilateral ACL rupture. Three-dimensional models of the bones and articular surfaces were created from the pre- and postactivity scans. The pre- and postactivity models were registered to each other, and cartilage strain (defined as the normalized difference in cartilage thickness pre- and postactivity) was calculated in regions across the tibial plateau, femoral condyles, and femoral cartilage adjacent to the medial intercondylar notch. These measurements were compared between ACL-deficient and intact knees. Differences in cartilage thickness and strain between knees were tested with multiple analysis of variance models with alpha set at P < .05. Results: Compressive strain in the intercondylar notch was elevated in the ACL-deficient knee relative to the uninjured knee. Furthermore, cartilage in the intercondylar notch and adjacent medial tibia was significantly thinner before activity in the ACL-deficient knee versus the intact knee. In these 2 regions, thinning was significantly influenced by time since injury, with patients with more chronic ACL deficiency (>1 year since injury) experiencing greater thinning. Conclusion: Among patients with ACL deficiency, the medial femoral condyle adjacent to the intercondylar notch in the ACL-deficient knee exhibited elevated cartilage strain and loss of cartilage thickness, particularly with longer time from injury. It is hypothesized that these changes may be related to posttraumatic osteoarthritis development. Clinical Relevance: This study suggests that altered mechanical loading is related to localized cartilage thinning after ACL injury.

Sleep apnoea in the asymptomatic elderly: a real issue for the brain?

The link between sleep apnoea and brain structure is unclear; although dysfunction of the hippocampus, middle temporal gyrus and brainstem/cerebellum have been observed previously. However, this link has been little explored in elderly subjects. The aim of this study was to explore the link between sleep apnoea and the brain in an elderly population.226 asymptomatic elderly subjects (age mean±sd 75.3±0.9 years, range 72.3-77.8 years) from the PROOF (Evaluation of Ageing, Autonomic Nervous System Activity and Cardiovascular Events) cohort study were explored using linear voxel-based or cortical thickness with apnoea/hypopnoea index (AHI; mean±sd 15.9±11.5 events·h-1, range 6-63.6 events·h-1) as a covariate of main interest. The brain volumes of 20 control subjects, 18 apnoeic (AHI >29 events·h-1) treated patients and 20 apnoeic untreated patients from this population were compared using voxel-based morphometry, cortical thickness or surface-based analyses.AHI was not associated with any change in local brain volume, cortical thickness or cortex surface. Control subjects, apnoeic treated and untreated patients were not different in terms of local brain volume, cortical thickness or surface.In a specific population of asymptomatic elderly healthy subjects, sleep apnoea does not seem to be associated with a change in local brain volume or in cortical thickness.

Accelerated executive functions decline and gray matter structural changes in middle‐aged type 1 diabetes mellitus patients with proliferative retinopathy

The aim of the present study was to determine trajectories of cognitive and cortical changes over time in middle-aged patients with type 1 diabetes mellitus (T1DM) and proliferative retinopathy. Twenty-five patients and 25 controls underwent neuropsychological assessment and neuroimaging twice in a mean (±SD) of 3.56 ± 0.65 and 3.94 ± 0.91 years, respectively (P = 0.098). Cognitive assessment included the domains of general cognitive ability, memory, information processing speed, executive functions, attention, and motor and psychomotor speed. Symmetrized percentage change in local cortical thickness, surface area, and volume was determined using the FreeSurfer 6 vertex-wise general linear model method. Analyses were performed uncorrected and corrected for baseline systolic blood pressure and depressive symptoms. In patients versus controls, accelerated executive function decline was accompanied by, but not related to, lower left frontal and temporal surface area, left parietal and right frontal thickness, and bilateral frontal and right posterior cingulate volume (family-wise error [FWE]-corrected P < 0.05 for all). In patients, lower executive performance was related to loss of right precuneus surface area (PFWE = 0.005). Higher HbA1c during follow-up was related to executive function decline (r = -0.509, P = 0.016) and loss of left hemisphere surface area (rcorrected analysis = -0.555, P = 0.007). After 3.5 years of follow-up, middle-aged T1DM patients with proliferative retinopathy, mild focal changes in executive functions, and cortical structure were found, which may indicate accelerated aging.

Using Local Volume Expansion to Design Better Charging Protocols for Lithium-Ion Batteries

Introduction Reduction of charging time is desirable in most battery-powered applications and may be a key factor for wider acceptance of battery electric vehicles (BEVs). However, fast charging of lithium-ion cells may result in accelerated aging [1]. In state-of-the-art cells, lithium deposition on the graphite anodes is a significant mechanism of capacity loss, especially with high charging rates and/or low temperatures. In this work, we show that local cell expansion can serve as an indirect measure of lithium deposition and how this relationship can be used to design charging protocols that provide both beneficial battery cycle life and charging time. Experimental and Results A 2-D thickness scan setup [2] is used to measure locally resolved thickness changes of commercial pouch cells during operation. After accounting for thermal expansion, the thickness changes are linked to reversible and irreversible lithium plating. The analysis is underpinned by voltage relaxation [3] and post-mortem examination. It is shown that the locally resolved thickness measurement helps detect lithium deposition more reliably and at an earlier stage than a with single-spot or a surface-averaged thickness measurement. Finally, a screening of charging conditions and corresponding thickness changes is performed. Fast charging protocols are derived based on maximum allowable local irreversible thickness change. An extended cycling experiment serves as a proof of the cycle life advantage of our fast charging protocols compared to standard constant current – constant voltage charging. Acknowledgements This work has received funding from the European Union's Horizon 2020 research and innovation programme under the grant 'Electric Vehicle Enhanced Range, Lifetime And Safety Through INGenious battery management' (EVERLASTING-713771).

Effective absorption correction for energy dispersive X-ray mapping in a scanning transmission electron microscope: analysing the local indium distribution in rough samples of InGaN alloy layers.

We have applied our previous method of self-consistent k*-factors for absorption correction in energy-dispersive X-ray spectroscopy to quantify the indium content in X-ray maps of thick compound InGaN layers. The method allows us to quantify the indium concentration without measuring the sample thickness, density or beam current, and works even if there is a drastic local thickness change due to sample roughness or preferential thinning. The method is shown to select, point-by-point in a two-dimensional spectrum image or map, the k*-factor from the local Ga K/L intensity ratio that is most appropriate for the corresponding sample geometry, demonstrating it is not the sample thickness measured along the electron beam direction but the optical path length the X-rays have to travel through the sample that is relevant for the absorption correction.