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Based on the propagation principle of laser ultrasonics on the circumferential surface of metal specimens, this paper uses the scanning detection source method and the scanning excitation source method to locate and analyze. The defects on the circumferential surface of bolt blanks. A comparison reveals that the amplitude change of the ultrasonic wave peak near the defect is significantly greater when using the scanning excitation source method, which is more conducive to defect identification. By analyzing the relationship between the time difference of characteristic echoes Rr, R’r generated on the circumferential surface and the depth of defects, a quantitative calculation method for defect depth is studied. Through numerical fitting and comparative verification, this method can achieve the characterization of 0-1.5 mm defect depth within the allowable error range.

Attention lapses (ALs) are complete lapses of responsiveness in which performance is briefly but completely disrupted and during which, as opposed to microsleeps, the eyes remain open. Although the phenomenon of ALs has been investigated by behavioural and physiological means, the underlying cause of an AL has largely remained elusive. This study aimed to investigate the underlying physiological substrates of behaviourally identified endogenous ALs during a continuous visuomotor task, primarily to answer the question: Were the ALs during this task due to extreme mind‐wandering or mind‐blanks? The data from two studies were combined, resulting in data from 40 healthy non‐sleep‐deprived subjects (20M/20F; mean age 27.1 years, 20–45). Only 17 of the 40 subjects were used in the analysis due to a need for a minimum of two ALs per subject. Subjects performed a random 2‐D continuous visuomotor tracking task for 50 and 20 min in Studies 1 and 2, respectively. Tracking performance, eye‐video, and functional magnetic resonance imaging (fMRI) were recorded simultaneously. A human expert visually inspected the tracking performance and eye‐video recordings to identify and categorise lapses of responsiveness as microsleeps or ALs. Changes in neural activity during 85 ALs (17 subjects) relative to responsive tracking were estimated by whole‐brain voxel‐wise fMRI and by haemodynamic response (HR) analysis in regions of interest (ROIs) from seven key networks to reveal the neural signature of ALs. Changes in functional connectivity (FC) within and between the key ROIs were also estimated. Networks explored were the default mode network, dorsal attention network, frontoparietal network, sensorimotor network, salience network, visual network, and working memory network. Voxel‐wise analysis revealed a significant increase in blood‐oxygen‐level‐dependent activity in the overlapping dorsal anterior cingulate cortex and supplementary motor area region but no significant decreases in activity; the increased activity is considered to represent a recovery‐of‐responsiveness process following an AL. This increased activity was also seen in the HR of the corresponding ROI. Importantly, HR analysis revealed no trend of increased activity in the posterior cingulate of the default mode network, which has been repeatedly demonstrated to be a strong biomarker of mind‐wandering. FC analysis showed decoupling of external attention, which supports the involuntary nature of ALs, in addition to the neural recovery processes. Other findings were a decrease in HR in the frontoparietal network before the onset of ALs, and a decrease in FC between default mode network and working memory network. These findings converge to our conclusion that the ALs observed during our task were involuntary mind‐blanks. This is further supported behaviourally by the short duration of the ALs (mean 1.7 s), which is considered too brief to be instances of extreme mind‐wandering. This is the first study to demonstrate that at least the majority of complete losses of responsiveness on a continuous visuomotor task are, if not due to microsleeps, due to involuntary mind‐blanks. We used whole‐brain voxel‐wise functional magnetic resonance imaging, haemodynamic response analysis, and functional connectivity analysis to investigate changes in neural activity during complete attention lapses on an extended visuomotor task. This revealed that, if not due to microsleeps, the majority of lapses were due to transient suspensions of thinking—that is, mind‐blanks.

Tailored welded blanks (TWBs) technology can give an important possibility to obtain components in automobile industry satisfying lightweight strategies as well as satisfying increased crashworthiness, corrosion resistance, and accuracy. Friction stir welding (FSW) is a joining process, which can be well fitted to obtaining aluminum tailored blanks when compared to other conventional joining processes. This paper presents an experimental study on TWBs produced by FSW with dissimilar aluminum alloy thin sheets. The formability performance is investigated by obtaining forming limit curves with Nakajima test using different blank widths. The properties of welded AA5182/AA6061 alloy pair, 1 mm thick, are studied and the corresponding formability is compared to base materials. Different weld line orientations are defined related to sheet rolling direction and corresponding forming limit curves are obtained in addition to load–displacement behavior. Results show a dependency of TWB formability on weld line orientation, as well as a decrease of welded pair alloy formability when compared to base materials.

The present meta‐analysis aimed to summarize the extent to which second language vocabulary is learned from the most frequently researched word‐focused activities: flashcards, word lists, writing, and fill‐in‐the‐blanks. One hundred effect sizes from 22 studies were included in meta‐regression analyses and administered separately for the observations measured with meaning‐recall and form‐recall tests. The results revealed that the average percentage learning gains were 60.1% and 58.5% on meaning‐recall and form‐recall immediate posttests. These gains dropped to 39.4% and 25.1% on delayed meaning‐ and form‐recall tests, respectively. These results suggest that learning through word‐focused tasks is far from guaranteed. Moreover, the percentage learning gains among the different activities ranged from 18.4% to 77.0% on immediate posttests and from 23.9% to 73.4% on delayed posttests indicating that there is much variation in efficacy among the activities. Moderator analyses revealed that learners’ place of study and direction of learning affected learning.

Microplastics (MPs) are ubiquitous in the environment, in the human food chain, and have been recently detected in blood and lung tissues. To undertake a pilot analysis of MP contamination in human vein tissue samples with respect to their presence (if any), levels, and characteristics of any particles identified. This study analysed digested human saphenous vein tissue samples (n = 5) using μFTIR spectroscopy (size limitation of 5 μm) to detect and characterise any MPs present. In total, 20 MP particles consisting of five MP polymer types were identified within 4 of the 5 vein tissue samples with an unadjusted average of 29.28 ± 34.88 MP/g of tissue (expressed as 14.99 ± 17.18 MP/g after background subtraction adjustments). Of the MPs detected in vein samples, five polymer types were identified, of irregular shape (90%), with alkyd resin (45%), poly (vinyl propionate/acetate, PVAc (20%) and nylon-ethylene-vinyl acetate, nylon-EVA, tie layer (20%) the most abundant. While the MP levels within tissue samples were not significantly different than those identified within procedural blanks (which represent airborne contamination at time of sampling), they were comprised of different plastic polymer types. The blanks comprised n = 13 MP particles of four MP polymer types with the most abundant being polytetrafluoroethylene (PTFE), then polypropylene (PP), polyethylene terephthalate (PET) and polyfumaronitrile:styrene (FNS), with a mean ± SD of 10.4 ± 9.21, p = 0.293. This study reports the highest level of contamination control and reports unadjusted values alongside different contamination adjustment techniques. This is the first evidence of MP contamination of human vascular tissues. These results support the phenomenon of transport of MPs within human tissues, specifically blood vessels, and this characterisation of types and levels can now inform realistic conditions for laboratory exposure experiments, with the aim of determining vascular health impacts.

Precise measurement of tailor-welded blanks is crucial for quality control of laser welding. The difficulty in measuring the seam profile of similar gage tailor–welded blanks lies in lacking of solutions to locate their feature points such as those representing the laser stripe. A laser sensor–based method is proposed to measure tailor-welded blanks based on its laser stripe and texture features, from which the proposed algorithm is employed to extract the feature points for seam profile assessment. The algorithm is evaluated on a laser-based weld seam measurement system, the experiment results show that the proposed method measures the tailor-welded blanks with high accuracy and is suitable for online inspection.

In this study, sheet bulk metal forming (SBMF) processes for manufacturing sidewall-thickened cups were explored, including sheet forming processes for the preparation of cup billets and bulk forming processes for sidewall thickening. To avoid forging laps caused by the clearance between the cup corner and die during sidewall upsetting, a locally thickened tailored blank was designed and produced. To form tailored blanks, coining and orbital forming were compared, and a strategy based on a coining process with different lubrication conditions was analyzed. The tailored blanks were drawn to cups, which had sharp corners and were used as billets for the final upsetting operation to avoid the clearance and thus eliminate forging laps. Adopting upsetting with controllable deformation zone (U-CDZ) method, the cup sidewall was thickened. During forming, the buckling on the sidewall and laps on the corner were prevented. The numerical and experimental results indicate that sheet parts with complex sections can be formed using a tailored blank with the U-CDZ method.

Under the background of dual carbon policy as well as energy conservation, blanks with variable thicknesses (BVTs) which act as structural components have drawn extensive attention due to their excellent strength and formability and reasonable load-bearing distribution characteristics, particularly in the field of automotive manufacturing. With these advantages, the manufacturing technologies of these plates using more efficient rolling methods have thus emerged. This article summarizes four methods and their characteristics for manufacturing plates with variable thicknesses based on rolling technology. In addition, a review is conducted on the latest research progress of the metal flow and rolling theories of existing plates with different thicknesses in the longitudinal and transverse direction.

This study delved into the significance of double-pass friction stir welding (DP-FSW) and blank arrangement on aluminum tailor-welded blanks (TWBs) formability. The five different positions of TWBs fabricated from solution-annealed and precipitation-hardened AA2017-T6 and AA6061-T6 were utilized in experimentation and finite element analyses that evaluated formability. This effect of welding parameters and blank positions on TWB formability characteristics was investigated thoroughly through an extensive analysis that included experimental tests and finite elemental analysis. The results showed that adopting double-pass FSW approaches, against single-pass methods, significantly improved formability. Furthermore, the investigation of different blank positions during the welding process exhibited distinctive effects on formability, and the best configurations were found. These insights provide valuable guidance for optimizing FSW processes in producing aluminum TWBs, thus contributing to advancements in lightweight material fabrication across diverse industrial applications. The experimental and simulated results have a standard deviation of ± 5%. The deviation was decreased by treating the blank as five different zones rather than there.

With the development of lightweight vehicles, tailor-welded blanks (TWBs) are being increasingly used in the automotive industry. Splitting and wrinkling are the main defects occurring during the deep drawing of TWBs. Accordingly, in this paper, a new method to control the forming defects is introduced in the forming process of TWBs. The microstructure and mechanical properties of TWBs are characterised by metallography and tensile tests. Finite element analysis is conducted for an automobile rear door inner panel made of TWBs to analyse the deep drawing. Edge and notch cutting are introduced to address forming defects and reduce the number of stamping tools. The thinning index, thickening index and minimum distance between the material draw-in and trimming lines are defined as the measurable index to analyse the numerical results. Orthogonal experiments, numerical simulations and multiobjective experiments are conducted to optimise the forming parameters. The proposed method and optimised parameters are verified through experiments, the results of which are essentially consistent with the numerical simulation. Indeed, the proposed method can provide guidance in controlling defects associated with the deep drawing of TWBs for complex-shape automotive panels.