Excessive Thickness Research Articles

Rapid construction of nickel phyllosilicate with ultrathin layers and high performance for CO2 methanation

The traditional techniques for the synthesis of nickel phyllosilicates usually time-consuming and energy-intensive, which often lead to the formation of layers with excessive thickness due to uncontrolled crystal growth. In order to overcome these challenges, this work introduces a microwave-assisted synthesis strategy to facilitate the synthesis of Ni-phyllosilicate-based catalysts within an exceptionally short duration of only five minutes, attaining a peak temperature of merely 102 °C. To enhance the specific surface area and to increase the exposure of active sites, an investigation was conducted involving three surfactants. The employment of hexadecyl trimethyl ammonium bromide (CTAB) has yielded remarkable results, with an ultrahigh specific surface area reaching 535 m2 g−1 and an ultrathin lamellar thickness of 1.43 nm. The catalyst exhibited an impressive CO2 conversion of 81.7 % at 400 °C, 60 L g−1 h−1, 0.1 MPa. It also demonstrated a substantial turnover frequency for CO2 (TOFCO2) of 5.4 ± 0.1 × 10−2 s−1, alongside a relatively low activation energy (Ea) of 80.74 kJ·mol−1. Moreover, the catalyst maintained its high stability over a period of 100 h and displayed high resistance to sintering. To further elucidate growth temperature gradient of the catalyst and concentration gradient of the materials involved, COMSOL Multiphysics (COMSOL) simulations were effectively utilized. In conclusion, this work breaks the limitation associated with traditional, laborious synthesis methods for Ni-phyllosilicates, which can produce materials with high surface area and thin-layer characteristics.

Time-Dependent Changes of Extremity Volume and Tissue Alterations in Swollen Arms Caused by Taxanes.

Background: We aimed to determine the course of arm swelling caused by the use of taxanes and to identify valid predictors of persistent swelling. Methods and Results: A total of 15 patients with unilateral arm swelling that developed during the course, or within 3 months after termination, of postoperative taxane-based chemotherapy were included in the present study. The patients attended follow-up appointments every 3-6 months for 24 months after their initial visit. Their arm circumference was measured at each follow-up appointment, while ultrasonography of the skin and subcutaneous tissues was performed at the 0-, 6-, 12-, and 24-month follow-ups. Of the 15 patients, 12 (80%) saw their taxane-induced arm swelling resolved within a median of 12 months (range, 3-29 months) after their final taxane administration. Of the 12 patients whose swelling resolved, 9 did not use compression sleeves; however, their course of resolution did not differ from the other 3 patients who regularly used compression sleeves. In the three patients with persistent swelling, the excess subcutaneous thickness in the medial upper arm (median, 283%) was significantly greater than that in the patients whose swelling resolved (120%; p < 0.05) during their initial visits. Conclusions: Of the 15 patients included in the present study, 80% saw their taxane-induced arm swelling resolve within a median of 12 months after their final taxane administration, independent of the use of compression therapy. Persistent swelling may be predicted during the initial visit based on subcutaneous thickening of the medial upper arm.

Flexural performance of precast segmental continuous box girders with corrugated steel webs

Due to the existence of joints, the flexural performance of segmental assembled girders is different from that of monolithic cast girders. In order to study the flexural performance of precast segmental assembled box girder with corrugated steel webs, a static failure test on a precast segmental assembled continuous box girder with corrugated steel webs and variable cross-section and a monolithic cast continuous box girder with corrugated steel webs of the same size was carried out. The influence of the existence of joints on the deflection, strain, and prestress increment of precast segmental continuous girder with corrugated steel webs was analyzed. The parameter analysis was further carried out by the finite element method. The results showed that, at the initial loading stage, the joint had little effect on the displacement, and the deflection of the segmental assembled girder changed more rapidly than that of the monolithic cast girder. In the monolithic girder, cracks mainly occurred at the middle-support position of the middle span and pure bending sections. In the segmental beam, cracks were concentrated in the concrete on both sides of the joint. The number of cracks was relatively small and concentrated in the concrete on both sides of the joints of the loading segment and the middle support segment. The trends in the strain growth in the segmental beam and MB01 were consistent, and the values were similar. The strain growth trend of the segmental girder and the monolithic girder was consistent, and the values were similar at the initial loading stage. The external prestressed tendons in the segmental girder had a greater role in the loading process than those in the monolithic girder, and the normal stress in the segmental girder increased more rapidly during the bending process. In the ultimate loading state, the external prestressing force of the segmental girder was 2.01% higher than that of the monolithic girder. The number of segments was inversely proportional to the flexural capacity of the structure. Excessive thickness of the adhesive layer would adversely affect the crack resistance of the structure. This study will contribute to the engineering application of continuous composite box girders with corrugated steel webs.

Smart fin with automatic evaporation and regeneration for thermal management of high heat flux electronics

The high temperature of modern electronic devices poses great challenges to the safety and reliability of applications. Reasonable and effective control of device operating temperature for enhancing device performance and promoting the development of the electronics industry has a positive effect. Here, an innovative and efficient passive cooling technology is proposed to reduce the device temperature using polymerized metal fin and smart hydrogel to form smart fin. The smart fin carries away the waste heat generated by the device through evaporation and regeneration is accomplished by capturing water molecules from the environment. The smart fin is demonstrated to low down the temperature of a heater with heat flux of 2900 W/m2 by 48.3 °C and restores to its initial state after 160 min. At a threshold temperature of 60 °C, it promoted the maximum usage power by 49.4%. The evaporation and regeneration capacity of the smart fin can be controlled by ambient temperature, relative humidity, and smart hydrogel thickness. Specifically, high temperatures promote water evaporation and absorption, high humidity suppresses evaporation but favors absorption, and excessive thickness impedes water transport. This thermal management strategy with simple structure, low-cost, and easy-preparation is expected to become a universal technology in the electronics industry.

Improving the performance of Cu2ZnSn(S,Se)4 thin film solar cells by SCAPS simulation

The effect of Se/(S + Se) ratio, absorber thickness, series and shunt resistance on Cu2ZnSn(S,Se)4 (CZTSSe) solar cells were studied by one-dimensional solar cell capacitance simulator (SCAPS-1D). The efficiency exhibited an initial increase followed by a subsequent decrease as Se/(S + Se) ratio increased, achieving peak efficiency of 17.38 % at Se/(S + Se) ratio of 0.2. As absorber thickness increased from 0.5 to 1.5 μm, both the short circuit current and efficiency exhibited continuous improvement, which was attributed to the enhanced absorption and utilization of sunlight. However, when the thickness of absorber exceeded 1.5 μm, the transport of carriers across the absorber was difficult due to the excessive thickness, and the efficiency was almost not improved. The optimal device possessed efficiency of 17.91 %. Series resistance exerted a more substantial influence on efficiency than shunt resistance. To achieve high-efficiency CZTSSe devices, series resistance should be controlled below 2 Ω·cm2, and shunt resistance should be controlled above 600 Ω·cm2.

Artificial Intelligence in Obstetric Anomaly Scan: Heart and Brain.

The ultrasound scan represents the first tool that obstetricians use in fetal evaluation, but sometimes, it can be limited by mobility or fetal position, excessive thickness of the maternal abdominal wall, or the presence of post-surgical scars on the maternal abdominal wall. Artificial intelligence (AI) has already been effectively used to measure biometric parameters, automatically recognize standard planes of fetal ultrasound evaluation, and for disease diagnosis, which helps conventional imaging methods. The usage of information, ultrasound scan images, and a machine learning program create an algorithm capable of assisting healthcare providers by reducing the workload, reducing the duration of the examination, and increasing the correct diagnosis capability. The recent remarkable expansion in the use of electronic medical records and diagnostic imaging coincides with the enormous success of machine learning algorithms in image identification tasks. We aim to review the most relevant studies based on deep learning in ultrasound anomaly scan evaluation of the most complex fetal systems (heart and brain), which enclose the most frequent anomalies.

The Plastic Deformation Mechanism in Nano-Polycrystalline Al/Mg Layered Composites: A Molecular Dynamics Study.

Understanding plastic deformation behaviour is key to optimising the mechanical properties of nano-polycrystalline layered composites. This study employs the molecular dynamics (MD) simulation to comprehensively investigate the effects of various factors, such as grain sizes, strain rates, and the interlayer thicknesses of the intermetallic compounds (IMCs), on the plastic deformation behaviour of nano-polycrystalline Al/Mg layered composites. Our findings reveal that the influence of grain size on deformation behaviour is governed by the strain rate, and an increase in grain size is inversely proportional to yield stress at low strain rates, whereas it is positively proportional to tensile stress at high strain rates. Moreover, an optimal thickness of the intermediate layer contributes to enhanced composite strength, whereas an excessive thickness leads to reduced tensile strength due to the fewer grain boundaries (GBs) available for accommodating dislocations. The reinforcing impact of the intermediate IMCs layer diminishes at excessive strain rates, as the grains struggle to accommodate substantial large strains within a limited timeframe encountered at high strain rates. The insights into grain sizes, strain rates, and interlayer thicknesses obtained from this study enable the tailored development of nanocomposites with optimal mechanical characteristics.

Single-track investigation of additively manufactured mold steel with larger layer thickness processing: Track morphology, melt pool characteristics and defects

Large layer thickness is essential to increase building rate, but excessive layer thickness easily lead to defects which negatively affect component quality. The evolution of track morphology, melt pool characteristics and defects of additively manufactured mold steel by using various larger layer thickness (60 and 90 μm) while also varying the laser energy density was investigated systematically. Results indicated that the morphologies of single tracks shifted sequentially from discontinuousness to continuous irregularity and continuous regularity with the increasing line energy density at 60 μm layer thickness. The width and depth of melt pool increased substantially with the line energy density increased from 0.4 to 1.3 J/mm, while the height of melt pool was nearly constant. Correspondently, transition of the melt pool based on the depth-to-width ratio from balling to conduction and keyhole modes was observed. When the layer thickness increased from 60 to 90 μm, the average build percentage of the single tracks decreased by 43 % with increasing line energy density from 0.26 to 0.51 J/mm, and more spatters around the surface of tracks were found at 0.8 J/mm. Interestingly, the average width of the melt pool decreased by 37 μm, while the height of melt pool increased by 45 μm. More small spherical gas pores (5–15 μm) occurred in bottom of keyhole due to trapped vapor at high energy density. The decrease in melt width with increased layer thickness is most likely due to the weakened Marangoni convection. Finally, formation mechanism of lack-of-fusion defects and gas pores with larger layer thickness processing were analyzed based on melt pool characteristics, such as spheroidization, keyhole and spatters.

Mapping strain across Co80Ta7B13 / Co62Ta6B32 glassy interfaces

While multilayered thin film metallic glasses offer promising mechanical properties due to their interfaces, the correlation between chemical composition and and strain at the interfaces has not been investigated so far. Hence, atomic distance and composition variations across glassy Co80Ta7B13 / Co62Ta6B32 interfaces are revealed by correlative transmission electron microscopy, nanobeam precession electron diffraction (NBPED) mapping and atom probe tomography (APT). A composition dependent mean atomic distance is identified for the individual layers. At the interfaces, a chemically graded region of 4 nm thickness is observed with APT, while the mean atomic distance gradient - investigated by NBPED mapping - extends over 9 nm and cannot solely be explained by chemical composition changes. Instead, the excess thickness of the atomic distance gradient compared to the chemical gradient can be rationalized by the presence of strain at the interface.

Highly conductive thin lamellar Li7La3Zr2O12/Li3InCl6 composite inorganic solid electrolyte for high-performance all-solid-state lithium battery

Garnet-type oxide Li7La3Zr2O12 (LLZO) has attracted considerable attention as promising solid-state electrolyte (SSE) owing to the exceptional bulk ion conduction. However, the Li+ transfer capacity of most LLZO-based solid electrolytes remains inadequate, primarily due to the presence of extensive grain boundaries and excessive thickness. Herein, we report the fabrication of a LLZO-based lamellar composite inorganic solid electrolyte (LLZO/LIC LISE) by in-situ sintering Li3InCl6 (LIC) in LLZO lamellar framework. LIC can act as an effective Li+-conductive grain boundary modifier within the electrolyte, leading to a remarkable reduction in grain boundary resistance of LLZO/LIC LISE (<9.2 Ω cm2), which is much lower than that of LLZO lamellar framework (827.2 Ω cm2). Together with the reduced internal grain boundary of LLZO nanosheet, a high ionic conductivity of 3.22 × 10−4 S cm−1 at 25 °C is obtained for LLZO/LIC LISE. In addition, combining with the thin thickness of 29 μm, LLZO/LIC LISE obtains high ionic conductance of 223 mS and exceptional energy density of 246 Wh kg−1, surpassing most developed SSEs. As a result, the cell assembled with LLZO/LIC LISE achieves superior cycling performance of 144.2 mAh g−1 after 200 cycles at 0.5C with a capacity decay of only 0.055% per cycle. This study may present a facile approach to effectively eliminate the grain boundary resistance of inorganic solid electrolytes toward high-performance all-solid-state lithium batteries.

Experimental study on seismic performance of low strength shear walls strengthened with modified reactive powder concrete

Improper operation during construction and damages in long-term use environments will result in the shear walls being unable to meet seismic design and safety requirements. In order to further explore the impact of modified reactive powder concrete (MRPC) surface strengthening on the bending performance of shear walls, four shear walls were subjected to low cyclic loading tests. The effects of single-sided strengthening, double-sided strengthening, and different strengthening thicknesses on their seismic performance such as failure mode, deformation capacity, energy dissipation capacity, and stiffness degradation have been studied. The results show that the failure modes of four shear wall specimens were bending failure. Horizontal and oblique cracks appeared at the bottom and middle of the specimen, respectively, and the concrete at the corner was crushed and peeled off. For the specimen strengthened by MRPC, the strengthening layer was slightly warped, and the number of cracks is significantly reduced, which can effectively avoid the brittle failure of the specimen. The strengthening layer formed a good restraint on the internal concrete. MRPC can effectively improve the seismic performance of low bending strength concrete shear walls, and the ductility was far exceeded the expectations of the experiment. Double-sided strengthening was better than single-sided strengthening. Increasing the strengthening thickness can improve the flexural cracking capacity, but due to the interface between the shear wall and MRPC, it had little effect on the yield, peak and ultimate capacity. In addition, excessive thickness will reduce the ductility and energy dissipation capacity of the specimen.

Implant retained prosthesis on a free fibula flap: A challenging procedure for prosthetic and soft tissue management

A 39-year-old woman who had undergone fibular flap reconstruction and simultaneous implant placement after the surgical removal of a cemento-ossifying fibroma was experiencing mild discomfort 3 years later and requested an implant-supported prosthesis to restore her edentulous left maxillary quadrant. Initially, an interim removable partial denture was provided and later duplicated with clear resin. The interim prosthesis identified the excessive thickness of the grafted cutaneous soft tissue and the inadequate emergence angle of the nonfunctioning implants. By using the interim prosthesis as a surgical guide, vestibuloplasty was performed to thin the peri-implant soft tissue and the excessive skin graft from the initial maxillofacial surgery. Concurrently, the emergence angle of the implant was corrected with angled multi-unit abutments. A tissue compression stent was then made and attached to the abutments to guide the soft tissue healing process. When the peri-implant soft tissue had stabilized, a definitive implant-supported prosthesis was provided.

Microstructure control of Ti-based conversion coatings for optimizing organic coating properties in A6063 and A3003 alloys

Ti-/Zr-based conversion coatings are environmentally friendly alternatives to conventional chromate conversion coatings. A prerequisite for their widespread use on aluminum alloys is an efficient treatment process applicable to multiple alloys. In this study, Ti-based conversion coatings with an ideal microstructure were successfully formed on both A6063 and A3003 under the same conversion bath conditions. These coatings exhibited satisfactory impact adhesion with organic coatings and salt spray corrosion resistance for practical applications. In-depth analyses of the deposition process of Ti-based conversion coatings by scanning and transmission electron microscopy showed that Ti-oxide nanoparticles were initially deposited on the matrix, which grew into a continuous layer on A6063, whereas a continuous Ti-oxide layer was formed on A3003 from the initial immersion stage. Lowering the pH of the conversion bath prevented the continuous growth of the Ti-oxide layer on A6063, thereby reducing the adhesion and corrosion resistance. Increasing the bath concentration accelerated the growth rate of Ti oxides in A3003 and A6063, and the formation of Ti oxides with excessive thickness reduced the adhesion. By optimizing the concentration and pH, a continuous Ti-oxide layer of 20–40 nm thickness was formed with a reasonable growth rate on both A6063 and A3003, resulting in satisfactory impact adhesion and salt spray corrosion resistance.

Effects of Bitumen Thickness on the Aging Behavior of High-Content Polymer-Modified Asphalt Mixture.

The film thickness of asphalt mixtures is critical for determining their performance and aging durability. However, understanding of the appropriate film thickness and its influence on performance and aging behavior for high-content polymer-modified asphalt (HCPMA) mixtures is still limited. This research aims to examine the relationship between film thickness, performance, and aging behavior of HCPMA mixtures in order to establish an optimal film thickness that ensures satisfactory performance and aging durability. HCPMA specimens with film thicknesses ranging from 6.9 μm to 17 μm were prepared using a 7.5% SBS-content-modified bitumen. Various tests, including Cantabro, SCB, SCB fatigue, and Hamburg wheel-tracking tests, were conducted to evaluate raveling, cracking, fatigue, and rutting resistance before and after aging. The key findings indicate that insufficient film thickness negatively affects aggregate bonding and performance, while excessive thickness reduces mixture stiffness and resistance to cracking and fatigue. A parabolic relationship between the aging index and film thickness was observed, suggesting that increasing film thickness improves aging durability up to a point, beyond which excessive thickness adversely impacts aging durability. The optimal film thickness for HCPMA mixtures, considering performance before and after aging and aging durability, falls within the 12.9 to 14.9 µm range. This range ensures the best balance between performance and aging durability, offering valuable insights for the pavement industry in designing and utilizing HCPMA mixtures.

Diagnostic surface horizon vs. conventional surface horizon: The impact of topsoil delineation on the results of topsoil organic carbon density assessment in China

Accurate assessment of the topsoil organic carbon density (TSOCD) is of great importance for the management and conservation of the topsoil organic carbon pools. The conventional surface horizon (CSH) delineation method, which involves specifying a uniform topsoil thickness for all sampling points across a study area, carries the potential risk of inaccurate TSOCD estimation. Chinese soil scientists developed the definition and determination criteria for diagnostic surface horizon (DSH) in Chinese Soil Taxonomy (CST), which were based on the distinctive characteristics of topsoil in China. This study employed a DSH-based topsoil classification method to evaluate the TSOCD of China, based on the findings of the recent national soil survey. Also, TSOCD was calculated for all sample points based on the CSH method, where the thickness of CSH was defined as 5, 10, 15, 20, 30, and 60 cm from the surface. The results showed that DSH-based TSOCD in China ranged from 0.03 to 74.63 kg m−2 with a mean value of 4.34 kg m−2. The standardized topsoil delineation based on the DSH method shows great potential for improving the accuracy of TSOCD assessment and different DSH types exhibited very significant differences in TSOCD (p < 0.01). There was a significant difference between the TSOCD results based on the six CSH delineation thicknesses (p < 0.01). Excessive or insufficient uniform CSH thickness settings may result in over- or underestimation of TSOCD values in comparison to DSH. This study provides evidence that specific uniform thickness delineations are suitable for particular soil types, climatic conditions, and land use patterns, and that the mean TSOCD results derived from these delineations do not significantly differ (p < 0.01) from those based on DSH. The findings of this study have the potential to support the development of more accurate surface horizon delineation methods for managing and making decisions related to topsoil organic carbon pools.

Application and Progress of Artificial Intelligence in Fetal Ultrasound.

Prenatal ultrasonography is the most crucial imaging modality during pregnancy. However, problems such as high fetal mobility, excessive maternal abdominal wall thickness, and inter-observer variability limit the development of traditional ultrasound in clinical applications. The combination of artificial intelligence (AI) and obstetric ultrasound may help optimize fetal ultrasound examination by shortening the examination time, reducing the physician's workload, and improving diagnostic accuracy. AI has been successfully applied to automatic fetal ultrasound standard plane detection, biometric parameter measurement, and disease diagnosis to facilitate conventional imaging approaches. In this review, we attempt to thoroughly review the applications and advantages of AI in prenatal fetal ultrasound and discuss the challenges and promises of this new field.

First-principles study of the optical properties of BaMoO[formula omitted]/SrHfO[formula omitted] hyperbolic metamaterials

The theoretical applications of hyperbolic metamaterials have generated excitement in multiple fields, particularly in super-resolution optics. In practice, however, the potential of HMMs has been limited by the shortcomings of their constituent parts. Primarily, these are high losses and instabilities in the metal component, which is typically gold or silver, and excessive thickness in both types of layers. In this paper, we use density functional theory to investigate BaMoO3-SrHfO3 metamaterials. We predict that these are hyperbolic throughout the visible range and have the potential to mitigate many of these limitations, including a significant loss reduction. We also examine the accuracy of the effective-medium theory, which is used to predict the bulk optical properties of multilayered HMMs.

Multiscale investigation of self-consolidating earthen materials using a novel concrete-equivalent mortar approach

Earth-based materials have been used since ancient times due to their low environmental impact and superior thermal performance. The rammed earth (RE) method, as a common earthen construction, consists in casting the material layer-by-layer, which is time-consuming, labor-intensive, and energy consuming. Designing self-consolidating earth concrete (SCEC) can speed up the construction process and overcome the disadvantages of conventional RE and enhance its performance. Achieving high fluidity and adequate compressive strength for early demolding is challenging because of the presence of clay and low cement content, respectively. Moreover, diversity of existing soil types does not allow to propose a universal mixture proportioning approach. In this study, workability, drying shrinkage, and compressive strength of SCEC mixtures were evaluated using a new concrete-equivalent mortar (CEM) approach to facilitate the optimization process and reduce the number of experiments and materials. The approach is mainly based on optimizing the excess paste (EP) thickness to consider the variation of packing density of the granular skeleton. The mixture parameters included the water-to-powder ratio (W/P), volumetric sand-to-total aggregate ratio (S/A), and the excess paste thickness. Good correlations between the investigated CEMs and their corresponding concrete mixtures were established. According to the carried-out ANOVA analysis, the main influencing parameters on workability, drying shrinkage, and compressive strength of SCEC include the specific surface area and Atterberg limits of the ternary binder system, W/P, paste volume, and EP thickness.

Convective Self‐Compression of Cratons and the Stabilization of Old Lithosphere

AbstractDespite being exposed to convective stresses for much of the Earth's history, cratonic roots appear capable of resisting mantle shearing. This tectonic stability can be attributed to the neutral density and higher strength of cratons. However, the excess thickness of cratons and their higher viscosity amplify coupling to underlying mantle flow, which could be destabilizing. To investigate the stresses that a convecting mantle exerts on cratons that are both strong and thick, we developed instantaneous global spherical numerical models that incorporate present‐day geoemetry of cratons within active mantle flow. Our results show that mantle flow is diverted downward beneath thick and viscous cratonic roots, giving rise to a ring of elevated and inwardly‐convergent tractions along a craton's periphery. These tractions induce regional compressive stress regimes within cratonic interiors. Such compression could serve to stabilize older continental lithosphere against mantle shearing, thus adding an additional factor that promotes cratonic longevity.

Tibial Post Refracture in Posterior-Stabilized Total Knee Arthroplasty Following Isolated Tibial Insert Exchange.

We report 4 cases with a tibial post refracture following isolated tibial insert exchange in posterior-stabilized total knee arthroplasty at a single center. In our institution, 27 cases (26 patients) underwent reoperation due to tibial post fracture in posterior-stabilized total knee arthroplasty between July 2008 and November 2020. Of these 27 cases, 4(4 patients) tibial post refractures occurred at a mean follow-up period of 9.1 years. All 4 cases of tibial post refracture occurred in a group of 21 cases with isolated tibial insert exchange. There was no tibial post refracture in patients with a tibial revision surgery. The incidence of this complication following isolated tibial insert exchange was 19.0%. The mean elapsed time from tibial insert exchange to the diagnosis of a post refracture was 2.5 years (range: 1.1-6.6 years). Isolated exchange of a tibial insert with excessive thickness as a treatment for tibial post fracture is associated with a high probability of tibial post refracture. The treatment method should be selected after a thorough analysis according to the cause of fracture. IV.