Sequential Casting Research Articles

Direct Precursor Route for the Fabrication of LLZO Composite Cathodes for Solid-State Batteries.

Solid-state batteries based on Li7La3Zr2O12 (LLZO) garnet electrolyte are a robust and safe alternative to conventional lithium-ion batteries. However, the large-scale implementation of ceramic composite cathodes is still challenging due to a complex multistep manufacturing process. A new one-step route for the direct synthesis of LLZO during the manufacturing of LLZO/LiCoO2 (LCO) composite cathodes based on cheap precursors and utilizing the industrially established tape casting process is presented. It is shown that Al, Ta:LLZO can be formed directly in the presence of LCO from metal oxide precursors (LiOH, La2O3, ZrO2, Al2O3, and Ta2O5) by heating to 1050°C, eliminating the time- and energy-consuming synthesis of preformed LLZO powders. In addition, performance-optimized gradient microstructures can be produced by sequential casting of slurries with different compositions, resulting in dense and flat phase-pure cathodes without unwanted ion interdiffusion or secondary phase formation. Freestanding cathodes with a thickness of 85µm, a relative density of 95%, and an industrial relevant LCO loading of 15mg show an initial capacity of 82 mAh g-1 (63% of the theoretical capacity of LCO) in a solid-state cell with Li metal anodes, which is comparable to conventional LCO/LLZO cathodes and can be further improved in the future.

Morphologically engineered multi-component organic solar cells with stratified donor distribution and alloyed acceptors for enhanced efficiency and stability

The strategy of integrating multiple components within the bulk-heterojunction layer of organic photovoltaics (OPVs) has proven effective in enhancing device performance and demonstrates broad potential applications. Nonetheless, achieving precise control over the morphology in such a multifaceted system presents a significant challenge. In this work, we introduce an innovative sequential casting technique to fabricate highly efficient quaternary OPVs with a meticulously tailored morphology featuring layers of stratified donor distribution and composite alloyed acceptors. The layered configuration of D18/PTQ10, with distinct crystalline domains, establishes a dedicated hole-transport pathway, while the alloyed BTP-eC9:Y6-O acceptors are evenly dispersed across the layered D18/PTQ10 donor phase. This carefully crafted morphology presents a gradient and interpenetrated donor/acceptor phase separation at an ideal length scale, which facilitates exciton dissociation, minimizes energetic disorder, and mitigates recombination. As a result, a power conversion efficiency close to 19% with excellent operational stability (extrapolated T80 = 818 h) was achieved. This work offers valuable insights into the morphological engineering of multicomponent OPVs for improved performance.

Hollow-adjustable polymer microneedles for prolonged hypoglycemic effect on diabetic rats

Maintaining blood glucose levels within a safe range is critical for diabetic management. In recent decades, microneedles (MNs) have emerged as a potential method for delivering drugs to treat diabetes. However, insufficient drug loading and the complexity of achieving long-acting release have presented challenges that research has not addressed well. In this study, the hollow-adjustable biocompatible polymer MNs with varying cavity volumes were developed by cyclic freeze-thawing technique. The structure of shell-layer of hollow MNs was optimized with a sequential casting approach for regulating drug release kinetics. This design can ensure the sufficient mechanical strength of MNs and help to improve the drug-loading capacity, thereby solving the problem of low drug-loading capacity and short pharmacodynamic action time of traditional polymer MNs. In vivo experiments performed on diabetic rat models revealed the potential of the as-fabricated MNs to effectively pierce into the skin, leading to a notable hypoglycemic effect lasting up to 14 h without inducing the risk of hypoglycemia. These results indicate that the fabricated hollow-adjustable polymer MNs is a potential candidate for transdermal delivery of high-dose drugs.

The Investigation of Current Collector Layers and Design Modification of SOFCRoll Cell with LCNT-Based Electrode

The Solid Oxide Fuel Cells (SOFCs) with an alternative fuel electrode based on the nickel-doped lanthanum calcium titanate (La0.43Ca0.37Ni0.06Ti0.94O3-γ, LCNT) were produced with alternative SOFCRoll geometry. The SOFCRoll is a self-supporting cell based on a double spiral shape, where all the layers are tape cast, rolled and fired in a single step. The SOFCRoll has the advantage of the planar system, thick film manufacturing techniques, robustness of the tubular design and very high volumetric surface area. In the previous work, 27.75 cm2 of surface area was incorporated in a spiral structure with a volume of about 2.5 cm3.For cell production, all tapes were cast on each other by sequential casting and co-sintered at 1350 °C. The cell assembly included one layer of La0.43Ca0.37Ni0.06Ti0.94O3-γ /Zr0.92Y0.08O2-γ composite fuel electrode with 50% of LCNT by volume (LCNT/YSZ50), two layers of Zr0.92Y0.08O2-γ (YSZ) electrolyte, one layer of (La0.8Sr0.2)0.95MnO3 /Zr0.92Y0.08O2-γ active oxygen electrode with 50% of LSM (LSM/YSZ50), and LSM/YSZ current collector layer with high 90% of LSM content (LSM/YSZ10). The described methodology allowed to co-sinter four different layers of ceramic material and produced a stable SOFCRoll cell with minimum internal defects. The shrinking profile during sintering was the most crucial factor and was controlled by the initial pre-sintering of the material and the size of the particles.The current paper presents further work on cell optimisation to improve the current collection and gas distribution within a cell structure. The design modification and co-sintering of the current collector fuel electrode layer with high Ni content allowed for the optimal use of 12 cm2 surface area in the smaller cell version. The use of shorter tapes gave shorter diffusion and current collection distance; also, the LSM/YSZ10 layer was not needed, as the whole area of the oxygen electrode was exposed for current collection purposes. While for the fuel electrode side, new tapes for the current collector were developed, such as LCNT/Ni50 composite with 50% of Ni by volume and Ni/YSZ10 composite with 90% of Ni by volume. Moreover, the co-casting method for SOFCRoll preparation was modified and improved. Giving better control over co-cast tape parameters and letting to avoid structural defects created during a cell assembly.The paper aims to deliver the complete procedures behind the manufacturing and testing of SOFCRoll with a new configuration and assembly. These include the guidelines for material preparation and processing, tapes development, analysis of shrinking profile, cell assembly, set up of electrochemical test, data interpretation and post-mortem analysis.

Pain behavior of children with bilateral idiopathic clubfoot undergoing Ponseti casting and the effect of non-pharmaceutical pain-relieving agents.

This study prospectively investigated the pain response and physiological parameters [heart rate (HR) and oxygen saturation (SpO2)] during sequential casting in bilateral clubfoot. Additionally, it explored the role of non-nutritive sucking and human care contact on the observed responses during casting. Subjects were allotted to control group (Group A with no intervention) and two intervention groups (Group B: non-nutritive sucking intervention, Group C: human care contact intervention). Neonatal Infant Pain Score (NIPS), heart rate (HR), and oxygen saturation (SpO2) were used to assess the response. The three groups matched in age and gender characteristics of the participants. Pain response was noted across all groups. The left foot demonstrated a statistically significant preexisting tachycardia which rose further during casting (p < 0.01). Intergroup comparisons revealed that the alteration for NIPS during casting was in following sequence (Group A > C > B, p < 0.00001). The effect of interventions offered in Group B and C lasted in the post-cast period as well (B > C). The clubfoot child exhibited moderate pain response during casting of both feet. A tachycardia was noted prior to initiation of second cast which further exaggerated with subsequent cast. Pacifier (non-nutritive sucking) intervention produced better control of pain response than human care contact during casting for both feet.

High‐Efficiency Binary Organic Solar Cells Enabled by Pseudo‐Bilayer Configuration in Dilute Solution

Forming proper film morphology in organic solar cells (OSCs) is important to govern the exciton dissociation and charge transport. Herein, high‐performance pseudo‐bilayer heterojunction (PBHJ) OSCs with donor:acceptor (D:A) bilayer architecture are reported by sequentially depositing two layers of diluted active solution with different D:A ratios. Such pseudo‐bilayer films can not only enable the cascaded components distributed in the vertical direction, but also afford large donor and acceptor (D/A) interfaces for efficient exciton dissociation. Additionally, the D:A active layer on the bottom substrate can act as a seed to promote the crystallization process of the upper film during the sequential casting process. The PBHJ strategy on two representative D:A blends, PM6:Y6 and PTQ10:Y6, is implemented. Benefiting from the synergetic effects of efficient exciton dissociation and balanced charge transport, the devices based on PM6:Y6 and PTQ10:Y6 show high power conversion efficiencies of 17.73% and 17.81%, respectively. Notably, the presented PBHJ devices are fabricated by using dilute chloroform solution (4 mg mL−1 for donor), demonstrating the excellent potential for poorly soluble donors and acceptors in future OSCs applications.

High-performance organic photodetectors enabled by a refined fibrillar multiphase morphology

Film morphology of donor:acceptor blend layers plays a critical role in photon-to-current efficiency and dark/noise current of organic photodetectors (OPDs). One effective approach to manipulate crystallization and mesoscale phase separation of such blend layers is sequential casting (SC). However, the guiding strategies to control the morphology and the impacts on OPD performance of the SC films remain elusive, as the film structural evolution during SC is different from conventional blend casting (BC). Here, a refined fibrillar multiphase morphology is demonstrated by SC in an NT812:IEICO-4F blend film, where the high-quality IEICO-4F crystallites infiltrate the robust NT812 fibril network from the surface to the bulk. Such a morphology leads to improved charge generation and collection, reduced trap states, and enhanced charge block capability of resultant device, enabling simultaneous achievement of high external quantum efficiency and low dark/noise current. A maximum special detectivity of 5 × 1013 Jones is achieved at 860 nm under –0.1 V, which is among the highest detectivities for vis-to-NIR OPDs. The linear dynamic range and response speed are also improved. Such enhancements are parallelly observed from OPD devices based on other blend systems with similar fibrillar refinement, which provides guidelines for film structure manipulation towards high OPD performance.

Versatile Sequential Casting Processing for Highly Efficient and Stable Binary Organic Photovoltaics (Adv. Mater. 33/2022)

Organic Solar Cells Forming an ideal bulk heterojunction morphology is a critical issue governing the photon to electron process in organic solar cells (OSCs). In article number 2203379, Lijian Zuo, Hongzheng Chen, and co-workers show how sequential-casting (SC) processing is practical and universal for improvement of device performance in both fullerene- and nonfullerene-based systems, in which the donor and acceptor are deposited sequentially. The fabricated OSCs show advantages regarding device performance, photostability and upscale fabrication. Such a film spin-coating method is analogous to the traditional Chinese pancake making process.

Versatile Sequential Casting Processing for Highly Efficient and Stable Binary Organic Photovoltaics.

Forming an ideal bulk heterojunction (BHJ) morphology is a critical issue governing the photon to electron process in organic solar cells (OSCs). Complementary to the widely-used blend casting (BC) method for BHJ construction, sequential casting (SC) can also enable similar or even better morphology and device performance for OSCs. Here, BC and SC methods on three representative donor:acceptor (D:A) blends are utilized, that is, PM6:PC71 BM, PM6:IT-4F and PM6:L8-BO. Higher power conversion efficiencies (PCEs) in all cases by taking advantage of beneficial morphology from SC processing are achieved, and a champion PCE of 18.86% (certified as 18.44%) based on the PM6:L8-BO blend is reached, representing the record value among binary OSCs. The observations on phase separation and vertical distribution inspire the proposal of the swelling-intercalation phase-separation model to interpret the morphology evolution during SC processing. Further, the vertical phase segregation is found to deliver an improvement of device performance via affecting the charge transport and collection processes, as evidenced by the D:A-ratio-dependent photovoltaic properties. Besides, OSCs based on SC processing show advantages on device photostability and upscale fabrication. This work demonstrates the versatility and efficacy of the SC method for BHJ-based OSCs.

Core-shell microneedle patch for six-month controlled-release contraceptive delivery.

There is a tremendous need for simple-to-administer, long-acting contraception, which can increase access to improved family planning. Microneedle (MN) patches enable simple self-administration and have previously been formulated for 1-2months' controlled release of contraceptive hormone using monolithic polymer/drug MN designs having first-order release kinetics. To achieve zero-order release, we developed a novel core-shell MN patch where the shell acts as a rate-controlling membrane to delay release of a contraceptive hormone, levonorgestrel (LNG), for 6months. In this approach, LNG was encapsulated in a poly(lactide-co-glycolide) (PLGA) core surrounded by a poly(l-lactide) (PLLA) shell and a poly(D,L-lactide) (PLA) cap that were fabricated by sequential casting into a MN mold. Upon application to skin, the core-shell MNs utilized an effervescent interface to separate from the patch backing within 1min. The core-shell design limited the initial 24h burst release of LNG to 5.8±0.5% and achieved roughly zero-order LNG release for 6.2±0.1months in vitro. A monolithic MN patch formulated with the same LNG and PLGA core, but without the rate-controlling PLLA shell and PLA cap had a larger LNG burst release of 22.6±2.0% and achieved LNG release for just 2.1±0.2months. This study provides the first core-shell MN patch for controlled months-long drug release and supports the development of long-acting contraception using a simple-to-administer, twice-per-year MN patch.

Numerical Analysis of the Influence of the Modification of the Ladle Shroud on Fluid Flow Behavior in a One-strand Tundish during Continuous Steel Casting

A tundish is a device from which liquid steel is pour into a mold. Therefore tundish hydrodynamic conditions have a significant impact on solidification during continuous steel casting (CSC) process. Modification of ladle shroud workspace, allows for the modification of liquid steel movement in the tundish. In the following work, numerical simulations were performed which allowed the impact of the modification of the ladle shroud workspace on the liquid steel flow structure in a one-strand tundish to be determined. In order to assess the impact of the modification of the ladle shroud on the behavior of the liquid steel in the tundish, simulations were performed, on the basis of which the percentage share of stagnant, ideal mixing and plug flow zones were determined. In addition, the mixing parameters were determined, allowing the estimation of casting duration during sequential casting. The flow fields of liquid steel for each modification of the ladle shroud were performed. The average velocity of liquid steel flowing through the tundish, the Reynolds number and turbulent intensity were also described. The obtained results showed, among others, that the application of three cylinders with a diameter of 0.041 m into the ladle shroud with a diameter of 0.11 m increases the share of active flow in the tundish in relation to the tundish with Conventional Ladle Shroud. At the same time, applying a ladle shroud with a diameter of 0.11 m during casting is the most favorable in relation to the hydrodynamics of the tundish.

OEIS Syndrome: Omphalocele, Exstrophy of the Cloaca, Imperforate Anus, and Spinal Defects

OEIS Syndrome: Omphalocele, Exstrophy of the Cloaca, Imperforate Anus, and Spinal Defects

Heating‐induced aggregation control for efficient sequential‐cast organic solar cells

AbstractThe aggregation and morphology within the photoactive layer is of considerable significance to boost the power‐conversion efficiency (PCE) of organic solar cells (OSCs). Herein, heating‐induced aggregation control of nonfullerene acceptor BTP‐eC7 during sequential casting was demonstrated. The large aggregates of BTP‐eC7 can be significantly reduced by sequential casting of BTP‐eC7 hot solution on the D18 fibrillar layer, and further eliminated by sequential casting of BTP‐eC7 hot solution on the D18 fibrillar layer heated on hot substrate, leading to stronger face‐on π–π stacking and appropriate phase separation within the photoactive layer to promote exciton dissociation and charge transfer. The maximum PCE of D18/BTP‐eC7 solar cells can be enhanced from 8.1% of room temperature casting to 15.9% of hot solution, hot‐substrate casting, therefore demonstrates that heating‐induced aggregation and sequential‐casting strategies are a promising approach in improving the performance of OSCs employing nonfullerene acceptors with limited solubility or strong crystallization ability.

The Evaluation of Deformity Correction in Idiopathic Clubfoot During Ponseti Casting Sessions: Two Scoring Methods Depicted Graphically

Background We graphically analyzed the correction of total Pirani and Dimeglio scores and their subcomponents at sequential casting sessions for children with idiopathic clubfeet. Methods Correction of scores at weekly sessions was represented graphically. The tenotomy effect was accounted for separately. We classified 1st to 3rd casts as early, 4th and 5th cast midlevel, and beyond 5 as final casts to describe casting treatment. Results A total of 88 clubfeet (34 bilateral) in 54 patients were studied. Both total Pirani and Dimeglio graphs were characterized by a steep fall in early casts; subsequent minimal improvement in midlevel and final casts; later marked correction with tenotomy. Equinus in both scores stood as the most resistant deformity, showed full correction only following tenotomy. Dimeglio graphs captured coupling of various foot motions better over early casts than Pirani graphs. Conclusions Both Pirani and Dimeglio scores can adequately guide caregivers to progressive deformity correction in clubfoot. Keywords: Clubfoot, CTEV, Pirani, Dimeglio, Scores, Graphs

Bioimprint Mediated Label-Free Isolation of Pancreatic Tumor Cells from a Healthy Peripheral Blood Cell Population.

New techniques are required for earlier diagnosis and response to treatment of pancreatic cancer. Here, a label-free approach is reported in which circulating pancreatic tumor cells are isolated from healthy peripheral blood cells via cell bioimprinting technology. The method involves pre-fabrication of pancreatic cell layers and sequential casting of cell surfaces with a series of custom-made resins to produce negative cell imprints. The imprint is functionalized with a combination of polymers to engineer weak attraction to the cells which is further amplified by the increased area of contact with the matching cells. A flow-through bioimprint chip is designed and tested for selectivity toward two pancreatic tumor cell lines, ASPC-1 and Mia-PaCa-2. Healthy human peripheral blood mononuclear cells (PBMCs) are spiked with pancreatic tumor cells at various concentrations. Bioimprints are designed for preferential retention of the matching pancreatic tumor cells and with respect to PBMCs. Tumor bioimprints are capable of capturing and concentrating pancreatic tumor cells from a mixed cell population with increased retention observed with the number of seedings. ASPC-1 bioimprints preferentially retain both types of pancreatic tumor cells. This technology could be relevant for the collection and interrogation of liquid biopsies, early detection, and relapse monitoring of pancreatic cancer patients.

Temporal Variation of Scores Along the Course of the Ponseti Treatment in Older Children: A Ready Guide to Progress of Treatment.

We aimed to graphically study the correction trend along the course of Ponseti treatment in older children with idiopathic clubfeet. The temporal variation of total Pirani and Dimeglio scores and their individual components at each casting session was represented graphically. Tenotomy correction was accounted for separately. We classified 0 to 4 as early, 4 to 8 as midlevel, and beyond 8 as late casts to describe the sequence of treatment. A total of 27 patients (39 feet; bilateral in 12) were studied. The average patient age was 4.78±2.36 years. Rigid equinus was the more severe pretreatment deformity in Pirani system and also the most difficult to treat component. Posterior crease and medial crease were least severe and were treated in early casts. Reducibility of lateral head of talus, curved lateral border of foot, and empty heel were moderately severe and showed a gradual improvement pattern over subsequent casting sessions. For Dimeglio components, equinus was the most resistant deformity, and it persisted until late casts. Adduction, rotation, and varus were moderately severe, and they followed a gradual improvement slope. Several components/scores did not turn 0 after correction for older clubfoot children. The treatment graphs for older clubfoot children adequately illustrated the initial severity, number of Ponseti casts used, correction of total scores and their individual components over sequential casting sessions, tenotomy influence, and the residual deformities.

A stochastic model of the process of sequence casting of steel, taking into account imperfect mixing

The process of sequential casting of steel, i.e. the procedure that implies a continuous change in the composition of the steel in the casting process of different steel grades, can be easily modelled assuming a perfect and instantaneous mix of the materials in the tundish. However, experimental evidence based on the measure of the local composition of steel billets obtained through this process suggests that the mixing of different steel grades in the tundish cannot be considered either perfect or instantaneous. An improved stochastic model, taking into account these effects, is presented and validated against the experimental results obtained using the laser-induced breakdown spectroscopy technique, assisted by an artificial neural network. In spite of the simplicity of the model proposed, the agreement between its predictions and the experimental results is remarkable.

Two-Phase Numerical Modeling of Grade Intermixing in a Steelmaking Tundish

The sequential casting of slabs is a major trend in the steel industry where steel quality is the most important factor. The operating parameters have the most influence on mixing phenomenon apart from the design and shapes of the tundish and its furniture. Moreover, in industrial practice, the bath height in tundish varied with time when the ladle is changed. In the present work, the numerical simulation has been carried out to study the effect of residual volume and outflow (throughput) rate on the mixing phenomenon inside the tundish. A transient, three-dimensional two-phase model using the Volume of Fluid (VOF) method and Level Set interface tracking method has been used to investigate the intermixed grade steel formation. A comparison of the two interface tracking schemes, i.e., Geo-reconstruct and Modified HRIC (High-Resolution Interface Capturing Scheme) has also been presented. The results obtained through numerical simulation has been compared with experimental results. In a later section, the results showed that residual volume has a significant effect on the grade mixing. The mixing phenomenon in tundish is considerably influenced by the advance-pouring box (APB). Further, the outflow rate of tundish has little impact on the grade intermixing phenomenon.

Gravity Casting Of Variable Composition Al Alloys: Innovation And New Potentialities

Aluminum alloys are the most employed light alloys in the automotive sector. Therefore, aluminum-alloy production process must be flexible and competitive in order to meet the market needs. This study analyzes an innovative production process for aluminum alloys that can be employed for engine components like pistons. This kind of engine parts are typically subjected in service to high temperatures and fatigue stresses. The aim of this work is to define a sequential casting process for the production of a Functionally Graded Material (FGM) component with high-temperature resistance and ductility. The employ of two distinct aluminum alloys is at issue

Thermal Properties of Multilayer Nanocomposites Based on Halloysite Nanotubes and Biopolymers

This paper reports a novel procedure to fabricate multilayer composite biofilms based on halloysite nanotubes (HNTs) and sustainable polymers. Among the biopolymers, the non-ionic (hydroxypropyl cellulose) and cationic (chitosan) molecules were selected. The nanocomposites were prepared by the sequential casting of ethanol solutions of hydroxypropyl cellulose and aqueous dispersions of chitosan/HNTs. The composition of the bio-nanocomposites was systematically changed in order to investigate the effect of the hydroxypropyl cellulose/HNTs ratio on the thermal properties of the films, which were investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG). DSC studies were conducted in the static air (oxidative atmosphere), while TG measurements were carried out under nitrogen flow (inert atmosphere). The analysis of DSC data provided the enthalpy and the temperature for the oxidative degradation of the bio-nanocomposites. These results were helpful to estimate the efficacy of the well-compacted middle layer of HNTs as a flame retardant. TG experiments were performed at a variable heating rate and the collected data were analyzed by the Friedman’s method (non-isothermal thermogravimetric approach) with the aim of studying the kinetics of the hydroxypropyl cellulose degradation in the multilayer nanocomposites. This work represents an advanced contribution for designing novel sustainable nanocomposites with excellent thermal behavior as a consequence of their peculiar multilayer structure.