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The rapid development of additive manufacturing, also known as three-dimensional (3D) printing, is driving innovations in both industry and academia. Direct ink writing (DIW), an extrusion-based 3D printing technology, can build 3D structures through the deposition of custom-made inks and produce devices with complex architectures, excellent mechanical properties, and enhanced functionalities. A paste-like ink is the key to successful printing. However, as new ink compositions have emerged, the rheological requirements of inks have not been well connected to printability, or the ability of a printed object to maintain its shape and support the weight of subsequent layers. In this review, we provide an overview of the rheological properties of successful DIW inks and propose a classification system based on ink composition. Factors influencing the rheology of different types of ink are discussed, and we propose a framework for describing ink printability using measures of rheology and print resolution. Furthermore, evolving techniques, including computational studies, high-throughput rheological measurements, machine learning, and materiomics, are discussed to illustrate the future directions of feedstock development for DIW. The goals of this review are to assess our current understanding of the relationship between rheological properties and printability, to point out specific challenges and opportunities for development, to provide guidelines to those interested in multi-material DIW, and to pave the way for more efficient, intelligent approaches for DIW ink development. [ABSTRACT FROM AUTHOR]

Photonic crystals enable further manipulation of light at the nanometer scale, and the preparation of photonic crystal inks becomes a novel approach in achieving multifunctional and customizable light manipulation. The unique physical structure of photonic crystals exhibits special structural colors, which find wide applications in fields such as displays, sensors, information storage and anti‐counterfeiting measures, printing, and biomedicine. Compared to traditional dye‐based inks containing chemical pigments, photonic crystal inks not only maintain vibrant colors for longer durations but also significantly reduce environmental harm. This article introduces the basic characteristics of photonic crystal inks, summarizes recent synthetic methods of some inks, and finally concludes with an overview and prospects of the applications and development directions of photonic crystal inks. [ABSTRACT FROM AUTHOR]

Silicone elastomers have a broad variety of applications, such as soft robotics, biomedical devices, and structural metamaterials. The extrusion‐based method known as direct ink write (DIW) has enabled the production of additively manufactured silicone structures. However, this method is limited to manufacturing mostly planar or pseudo‐3D structures. Due to the low self‐supporting capabilities of extruded strands for traditional silicone‐based "inks," obtaining tall or overhanging structures, or structures comprised by thin walls is not feasible. Here, a novel Fast Cure silicone‐based ink is demonstrated that enables manufacturing of complex 3D structures. The Fast Cure ink is a two‐part mixture and silicone structures are produced by inline mixing and coextrusion of a part containing a catalyst (part A) and a part containing a crosslinker (part B). By the virtue of crosslinking, the extruded strands rapidly rigidize, increasing their self‐supportive capacity. Hence, structures can be obtained with superior shape retention and previously unobtainable parts are realized that are tall, with aspect ratios higher than 3, and have overhanging features, achieving inclination angles smaller than 35° with respect to the printing plane. These minimal sag parts are achieved without requiring extra curing or mechanisms, support structures, or suspension baths. [ABSTRACT FROM AUTHOR]

Non-contact dispenser printing is a novel, high-precision, template-free, and inexpensive film-forming technique. The quality of printed films is mostly determined by the physicochemical characteristics of the ink, which also have a big effect on the performance of microelectronic devices. In this work, high-performance gas-sensitive ink was made with ZnO-SnO2 composite gas-sensitive materials as functional phases and ethylene glycol and glycerol as solvents, employing PEG400 as dispersion in place of conventional high molecular weight dispersants. ZnO-SnO2 composite gas-sensitive films were printed on micro-electromechanical system ( MEMS) micro-hotplates using non-contact dispenser method. The effects of PEG400 content and solid content on the physical and chemical properties of ink were discussed by measuring the viscosity, and suspension stability of the ink. The microscopic morphology of the film was observed by SEM. The results show that the composite gas-sensitive ink possesses printability and low-temperature sintering film-forming properties when the solid content is 15% (mass fraction, the same here in after) and the PEG400 content is 6%, and the prepared composite gas-sensitive film is uniform in thickness, with a smooth surface, regular edges, and a good response to acetone gas. [ABSTRACT FROM AUTHOR]

The powerful capability of multi‐stimulus‐responsive fluorescent hydrogen‐bonded organic frameworks (HOFs) to respond to external chemical or physical stimuli in various manners makes them appealing in advanced information encryption. However, it is still a global challenge to manipulate the fluorescence properties finely to achieve dynamic fluorescence properties in the time dimension. Here, a feasible strategy is shown to control the emission of materials by introducing a common SP photochromic compound (1′, 3′, 3′‐trimethyl‐6‐nitro‐spiro‐ [chromene‐2, 2′‐indoline]) into functionalized HOFs, to finely manipulate the fluorescence properties. Two kinds of HOFs are successfully synthesized by modifying the unbonded carboxylic group of HOFs with Tb3+ or 5‐hexene‐1‐ol termed Tb‐HOFs and HOF‐olefin, respectively. Then, spiropyran is loaded into the Tb‐HOFs or HOFs‐olefin and dynamic fluorescence emission can be well controlled by changing the lanthanide dopants and light stimulation time. Relying on the dynamic fluorescence emission, the multilevel information encryption including anti‐counterfeiting ink, QR code, base code, and time‐resolved information storage has been successfully demonstrated, and the security level has been greatly improved. This work opens an avenue for achieving time‐resolved information storage technology, where the “time factor” is equivalent to a dynamic key, which introduces countless unpredictable possibilities and makes imitation more challenging. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) ink is a primary type of ink used in additive manufacturing with 3D inkjet printing. However, ink aggregation presents a challenge in nano-inkjet printing, affecting the stability and quality of the printing fluid and potentially leading to the clogging of nanometer-sized nozzles. This paper utilizes a Dissipative Particle Dynamics (DPD) simulation to investigate the aggregation behavior of alumina in a blend of 1,6-Hexanediol diacrylate (HDDA) and Trimethylolpropane triacrylate (TMPTA). By analyzing the effects of solid content, polymer component ratios, and dispersant concentration on alumina aggregation, the optimal ink formulation was identified. Compared to traditional experimental methods, DPD simulations not only reduce experimental costs and time but also reveal particle aggregation mechanisms that are difficult to explore through experimental methods, providing a crucial theoretical basis for optimizing ink formulations. This study demonstrates that alumina ceramic ink achieves optimal performance with a solid content of 20%, an HDDA-to-TMPTA ratio of 4:1, and 9% oleic acid as a dispersant. [ABSTRACT FROM AUTHOR]

Direct ink writing (DIW), or robocasting, is emerging as a key additive manufacturing technique for ceramic materials. Nevertheless, controlling ink rheology, finding optimal ink properties for printability, and optimising final mechanical performance have consistently posed major challenges. This review addresses these critical aspects of ceramic DIW through a meta-analysis. It encompasses rheological data from various ceramic inks and reviews methods for tuning ink properties to improve printability. The collected rheological properties are integrated into various printability criteria and models, leading to the proposal of an empirical criterion based on two key rheological parameters. Furthermore, the mechanical properties of both dense and porous ceramic components are discussed, revealing their correlations with rheology and processing defects. The objective of this comprehensive work is to serve as a valuable toolkit and guideline, providing researchers with the necessary insights to develop superior ink formulations and enhance the mechanical performance of robocasted ceramic components. [ABSTRACT FROM AUTHOR]

The inherent brittleness of ceramics poses significant challenges in the fabrication of hollow ceramic fibers, severely constraining their practical applications. In this study, a novel method for creating three-dimensional hollow fiber ceramic structures using UV-assisted single-channel direct ink writing was demonstrated. A concentric single-channel nozzle featuring shell/core structure was devised through the coaxial embedding method, and this specially designed nozzle was manufactured using digital light processing technology. During the UV-assisted direct ink writing process, the photosensitive ceramic slurry can be rapidly cured in place under the irradiation of UV light, ensuring high fidelity of the printed components. The hollow fiber structure produced in this study has a circular, pentagram, triangular and quadrilateral inner core, which can be adjusted according to the designed nozzle structure. This approach facilitates a straightforward and expedited creation of scaffolds featuring small-diameter hollow fiber structures, broadening the scope of potential applications for direct ink writing. [Display omitted] [ABSTRACT FROM AUTHOR]

Induced pluripotent stem cells (iPSCs) have emerged as a revolutionary tool in cell therapies due to their ability to differentiate into various cell types, unlimited supply, and potential as off-the-shelf cell products. New advances in iPSCderived immune cells have generated potent iNK and iT cells which showed robust killing of cancer cells in animal models and clinical trials. With the advent of advanced genome editing technologies that enable the development of highly engineered cells, here we outline 12 strategies to engineer iPSCs to overcome limitations and challenges of current cell-based immunotherapies, including safety switches, stealth edits, avoiding graft-versus-host disease (GvHD), targeting, reduced lymphodepletion, efficient differentiation, increased in vivo persistence, stemness, metabolic fitness, homing/trafficking, and overcoming suppressive tumor microenvironment and stromal cell barrier. With the development of advanced genome editing techniques, it is now possible to insert large DNA sequences into precise genomic locations without the need for DNA double strand breaks, enabling the potential for multiplexed knock out and insertion. These technological breakthroughs have made it possible to engineer complex cell therapy products at unprecedented speed and efficiency. The combination of iPSC derived iNK, iT and advanced gene editing techniques provides new opportunities and could lead to a new era for next generation of cell immunotherapies. [ABSTRACT FROM AUTHOR]

In this article, we have explored the use of Mueller polarimetry for the detection and enhancement of alterations in questioned documents. Erasures, obliterations (with liquid paper and by pasting an additional layer of paper), and insertions (made with several inks) were studied in both regular and glossy paper. Promising results were obtained, which depend on the type of paper and the relation between the color of the ink and that of the illuminating light source. Erasures are easier to detect in glossy paper than in regular paper. Obliterations with liquid paper produced successful results in both types of paper, while detection of obliterations made with an additional layer of paper led to higher contrast for regular paper. Regarding the insertions, the black ball‐point ink could be differentiated from roller‐ball and gel‐pen ink, which is often difficult to achieve visually. The contrast observed between the two inks was higher for regular paper than for glossy paper. Although the results shown in this article are promising, a wider variety of papers and pen types must be tested to further develop the procedure. It has the advantage of being non‐destructive and far more economic than other methods. In some cases, the results can be complementary to those obtained by other methods (e.g., fluorescence with UV excitation and illumination with transmitted and oblique light), while in other cases the method offers unique advantages. [ABSTRACT FROM AUTHOR]

The effects of selected conservation treatments on brown inks have been investigated using inks prepared following historic recipes and applied to pure cellulose paper. Tests were carried out on both freshly prepared and on artificially preaged samples to enable the evaluation of the effects of ageing phenomena on the colour stability of the inks. The behaviour of the inks was studied by observation of changes occurring during treatment, accompanied by colorimetric measurements before and after the treatments. The goal of this study was to assess the risks posed to objects containing such inks by the selected treatments and to facilitate the design of safe treatment strategies for such objects. [ABSTRACT FROM AUTHOR]

Influenced by the spreading route of Buddhism, palm leaf manuscripts in China are mostly distributed in Yunnan province and Tibet. The ink of palm leaf manuscripts from Yunnan province is left in the incisions, while the ink of palm leaf manuscripts from Tibet is written on the surface. The two inks have different compositions and application techniques, which may lead to varying degrees of flaking and ink loss. Application technique and ink composition are crucial for conservation measures. In this study, non-destructive analysis techniques including a portable digital microscope, Fourier transform infrared spectroscopy (FTIR), and X-ray fluorescence (XRF) were undertaken to analyse the characteristics and preservation condition of inks applied with different techniques on palm leaf manuscripts. Morphologies indicated that the interaction of ink and support influence the type and extent of ink loss. FTIR and XRF results showed significant differences in ink composition between incised palm leaf manuscripts from Yunnan and surface-written manuscripts from Tibet. Manuscripts from different periods within the same region exhibited similarities in ink composition. This paper significantly contributes to understanding properties of inks, offering an essential reference for ink consolidation. [ABSTRACT FROM AUTHOR]

Objective: Due to inconsistent subjective assessment criteria and excessively long calculation responses, there is a high risk of mistakenly discarding suspected hemolytic plasma and inappropriately discarding suspected non-hemolytic plasma during plasma preparation, posing significant risks to patient safety and leading to waste. This study aims to resolue these problems. Methods: A thresholding method that integrates deep learning with color-changing ink concepts was developed. By employing an enhanced U-Net architecture for image segmentation, the study introduces an advanced attention mechanism, batch normalization, and a padding module to tackle issues such as mean estimation bias, computational inefficiencies, and limited receptive field sizes in spatial mapping relationships. The model was validated and compared using a self-collected sample dataset. Results: This study employed the color-changing ink boundary method for classification, enhancing the computational efficiency of plasma discrimination and reducing discrimination time, while ensuring the accuracy of plasma sample identification. The accuracy rate of the experimental results is 99.52%. Conclusion: The results indicate that the plasma discrimination accuracy of this model is superior to other discrimination models, and it is expected to be applied in clinical practice. [ABSTRACT FROM AUTHOR]

Carbon black, a key ingredient in ancient inks, is used today to make the porous electrodes found in many rechargeable batteries. Understanding how to control its microstructure can pave the way to better-performing batteries. [ABSTRACT FROM AUTHOR]

The effects of the addition of nanoparticles (NPs) of alumina (NA) and silica (NS) on the rheological properties of aqueous-based ceramic inks for material extrusion-based additive manufacturing (ME-AM) and sinterability of printed ceramic components were investigated. The inks were first designed using bimodal particle sizes of NPs with micro-alumina, and their solids fraction in printable inks was found to be dependent on the functionalization properties of NPs. NAs create a lubricating effect in the ink system and improve solids-loading in the ink. Meanwhile, NSs form silanol bonds in aqueous-based inks that increase viscosity and reduce solids-loading for a printable ME-AM ink. The inks containing NPs with higher solids-loading and optimized rheology were printed using ME-AM, and the printed components were sintered at 1400–1550 ºC. Adding NPs in the ink significantly improved the sinterability of printed shapes by enhancing sintering kinetics and filling-effects, with NS having a more significant effect than NA. [Display omitted] [ABSTRACT FROM AUTHOR]

The droplet formation process in inkjet printing is studied numerically and verified through a simulation model. The droplet formation process decides the printing quality of the coating, and a mathematical model is developed to understand the complete process from droplet formation to detachment. The Navier-Stokes equation is used to mathematically derive the droplet radius (rnumerical). COMSOL multiphysics is used for simulation and the radius (rsimulation) is calculated from the droplet mass. The rnumerical and rsimulation are compared for inks containing nickel, graphene, and nickel-graphene composite ink it is observed that the composite ink radiuses have the lowest difference (rsimulation - rnumerical = 0.085 µm). A droplet is formed at 1.47 mm from the nozzle inlet, for nickel-graphene ink, and after 1.5mm for other pristine inks. The results are verified through Z number, velocity profile, and droplet mass. The droplet formation observed from the velocity profile is earliest at 120 µs. It is seen that a stable droplet is generated at 100µs for nickel-graphene ink and at 200 µs for individual inks. [ABSTRACT FROM AUTHOR]

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Printing as a process itself generates many environmental concerns. The paper addresses ink management in terms of environmental issues in the label printing industry, focusing on its environmental implications. The goal is to demonstrate how a proper ink management system impacts overall printing process efficiency and environmental sustainability for printing companies. The paper introduces an empirical approach to managing components for label and packaging production, utilizing automatic ink dispensing systems. The results demonstrate that the proper management of ink dispensing to minimize waste in packaging printing is crucial for optimizing operating print costs, potentially reducing the amount of ink needed to prepare colors by 52% and achieving energy savings of 37%. This approach fulfills the goal of sustainability by addressing environmental, economic, and social concerns. By optimizing ink usage and energy consumption, companies can significantly reduce operating costs and enhance economic performance. Simultaneously, these practices improve product quality, meet consumer demands for sustainable packaging, and create better working conditions for employees. Future directions and practical implications for supporting operational excellence in production are also discussed. [ABSTRACT FROM AUTHOR]

The demand for cost‐effective and rapid processing of large‐area thin films in the photovoltaic industry has recently driven significant research interest. In this context, among the various approaches explored, printing devices, particularly perovskite solar cells (PSCs), have garnered considerable attention due to their potential for scalability and cost efficiency. Besides, solution printing is widely recognized as an appealing strategy for large‐area, cost‐effective, and high‐throughput production of PSCs. However, while substantial progress has been made in this process, challenges related to stability, uniformity, and scalability remain to be addressed. This review critically examines the key printing techniques and substrates employed in PSC fabrication. Then, given the significance of ambient air printing for industrial applications, fundamental challenges associated with achieving ambient air production of PSCs are discussed in detail. Moreover, the formulation strategies of perovskite ink in printing technologies are thoroughly explored, considering its crucial role in determining the performance and stability of printed PSCs. Finally, the printing process for various components of PSCs, including the perovskite absorber layer, charge transport layers (CTLs), and electrodes, is meticulously analyzed, highlighting current achievements and remaining hurdles. [ABSTRACT FROM AUTHOR]

Sol LeWitt, a pioneer of conceptual art, created during his career over 1350 wall drawings, including the Wall Drawing #736 (1993) at the Center for Contemporary Art Luigi Pecci in Prato (Prato, Italy). The painting, executed by Andrea Marescalchi and Antony Sansotta under LeWitt's instructions, features a grid of coloured rectangles obtained by overlapping different layers of inks. During a 2021 restoration by the Wall Paintings and Stuccoes Department of the Opificio delle Pietre Dure (Firenze, Italy), an in-depth investigation of the composition and the materials used by LeWitt's assistants in producing Wall Drawing #736 was performed. A multi-analytical approach entailing Raman spectroscopy, high-performance liquid chromatography coupled to diode array and high-resolution mass spectrometry, gas chromatography–mass spectrometry (GC–MS), and pyrolysis coupled with GC–MS was applied. Our results revealed the use of animal glue, shellac resin, paraffin wax, linseed oil, and various organic pigments. The binder in the preparation layer was identified as poly(vinyl acetate), while poly(n-butyl methacrylate) was determined as a fixative. This research provided valuable insights into LeWitt's techniques. The acquired knowledge on the paint technique is highly relevant in supporting conservators in restoration and consolidating the many wall drawings produced exploiting the same technique all over the world. [ABSTRACT FROM AUTHOR]

Archival writing material is an important carrier to record and reflect archival content, and its material and durability are closely related to the life of archives. The "Shuyede" press in Shandong Province, which originated in the reign of Kangxi (1662 AD–1722 AD) in the Qing dynasty, printed many important archives and ancient books of the Qing dynasty (1644 AD–1911 AD). In order to explore the material composition of woodblock printing ink from the Shuyede press, modern analytical and detection techniques such as scanning electron microscopy–energy-dispersive spectrometry (SEM-EDS), Fourier-transform infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC/MS), and pyrolysis gas chromatography–mass spectrometry (Py-GC/MS) were applied for the analysis and identification of the ink on woodblock plates from the Shuyede press. The results showed that two kinds of printing ink—pine soot ink and oil soot ink—used were in these woodblocks from the Shuyede press in the Qing dynasty in the collection of Shandong Museum, and the binding material in the ink was animal glue, indicating that both pine and oil soot inks were used as printing ink in the Qing dynasty. [ABSTRACT FROM AUTHOR]

Sol LeWitt, a pioneer of conceptual art, created during his career over 1350 wall drawings, including the Wall Drawing #736 (1993) at the Center for Contemporary Art Luigi Pecci in Prato (Prato, Italy). The painting, executed by Andrea Marescalchi and Antony Sansotta under LeWitt’s instructions, features a grid of coloured rectangles obtained by overlapping different layers of inks. During a 2021 restoration by the Wall Paintings and Stuccoes Department of the Opificio delle Pietre Dure (Firenze, Italy), an in-depth investigation of the composition and the materials used by LeWitt’s assistants in producing Wall Drawing #736 was performed. A multi-analytical approach entailing Raman spectroscopy, high-performance liquid chromatography coupled to diode array and high-resolution mass spectrometry, gas chromatography–mass spectrometry (GC–MS), and pyrolysis coupled with GC–MS was applied. Our results revealed the use of animal glue, shellac resin, paraffin wax, linseed oil, and various organic pigments. The binder in the preparation layer was identified as poly(vinyl acetate), while poly(n-butyl methacrylate) was determined as a fixative. This research provided valuable insights into LeWitt’s techniques. The acquired knowledge on the paint technique is highly relevant in supporting conservators in restoration and consolidating the many wall drawings produced exploiting the same technique all over the world.

Inkjet-printed micro-patterns on hydrophobic surfaces have promising applications in the fabrication of microscale devices such as organic thin-film transistors. The low wettability of the surface prevents the inkjet-printed droplets from spreading, connecting to each other, and forming a pattern. Consequently, it is challenging to form micro-patterns on surfaces with low wettability. Here, we propose a sequential printing and drying method to form micro-patterns and control their shape. The first set of droplets is inkjet-printed at a certain spacing and dried. The second set of droplets is printed between these dry anchors on the surface with low wettability. As a result, a stable bridge on the surface with low wettability forms. This printing method is extended to more complicated shapes such as triangles. By implementing an energy minimization technique, a simple model was devised to predict the shape of the inkjet-printed micro-patterns while confirming that their equilibrium shape is mainly governed by surface tension forces. The gradient descent method was utilized with parametric boundaries to emulate droplet pinning and wettability of the anchors and to prevent convergence issues from occurring in the simulations. Finally, the energy minimization based simulations were used to predict the required ink to produce dry lines and triangles with smooth edges. [ABSTRACT FROM AUTHOR]

The Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) legislation in Europe has limited the use of certain materials in the manufacturing of tattoo inks; in particular, Pigment Blue 15:3 and Pigment Green 7 have been banned for the use in tattoo inks and permanent makeups and all labels must include an accurate list of ingredients. This study analyzed green and blue inks from five different manufacturers distributed to the European market, all of which claim to be REACH compliant. Nine out of ten inks analyzed were found to not be compliant and four contained banned material. The polymorph of Pigment Blue 15 found in four inks was unable to be determined. The majority of inks showed labeling inaccuracies, including the addition of unlisted poly(ethylene glycol) and propylene glycol. This study highlights issues around REACH compliance of tattoo inks on the European market and the need for manufacturing protocols to ensure accurate labeling. [ABSTRACT FROM AUTHOR]

Hospitality and tourism experiences have impeccable capacities of transformation. Drawing on the experience advantage literature, the current research highlights the needs-based mechanisms through self-esteem, autonomy, meaningfulness, and relatedness in understanding the transformative power of hospitality and tourism experiences. Through a synthesis of past literature, we first synthesize how these four needs-based mechanisms have been addressed in the hospitality and tourism experience literature. Against the backdrop of socially conditioned trends evolving around the four needs-based mechanisms, we developed a "HEAL" model to outline the transformative functions of hospitality and tourism experiences, which are to H arbor, E volve, A waken and L ink individuals. Finally, our research calls for additional studies that contribute to advancing hospitality and tourism experiences' transformative power. [ABSTRACT FROM AUTHOR]

Abstract Raman spectral references for various formulations of iron gall inks, logwood inks and mixtures of both types were acquired during this study. The samples, either liquid or dry inks and applied on paper, were analysed using a portable Raman spectrometer, both with 852 and 785 nm excitation lines, and a confocal dispersive Raman microscope with two different excitations, namely 785 and 532 nm. It was found that longer wavelengths are more suitable for the analysis of iron gall inks and that the spectral response of logwood inks is relatively more dependent on the excitation line. For the mixtures, it is suggested analyses be performed with both longer and shorter wavelengths, since with a 785 nm line mainly the characteristic features of the metal-polyphenol complex in iron gall inks are detected, while the spectra collected with a 532 nm excitation contain information on the presence of logwood inks. The study was complemented by non-invasive reflectance infrared spectroscopy, which enabled the detection of tannic acid in iron gall inks and in the mixtures, and by micro-Fourier transform infrared (FTIR) spectroscopy to complement the reference set. The study aims to contribute to the development of non-invasive protocols for identification of inks in historic and artistic works on paper, such as manuscripts and drawings. Graphical Abstract

The demand for modern electronics and semiconductors has increased throughout the years, which has enabled the innovation and exploration of solution-processed deposition. Solution-based processes have gained a lot of interest due to the low-cost fabrication and the large fabrication areas without the need for high-vacuum equipment. In this study, we utilized the ZnO ink for inkjet printer ink to fabricate a thin film via Electrohydrodynamic printing. Three different ink solutions were prepared for experimentation. The EHD printing technique demonstrated the ink's compatibility with and without the modifications. The outcomes of the EHD printed materials were comparable with the spin-coated thin films. The EHD-printed films demonstrated better results in comparison to spin-coated films. Ra and Rq of the EHD film measured at 3.651 nm and 4.973 nm, respectively. It improved the absorbance up to two-fold at 360 nm wavelength and electrical conductivity up to 40% compared to the spin-coated films. Furthermore, the optimization of the printing parameters can lead to the improved morphology and thickness of the EHD thin films. [ABSTRACT FROM AUTHOR]

In preparing flexible sensors, electrohydrodynamic inkjet printing technology is a commonly used method to print and pattern functional inks uniformly with high precision. This paper reviews the latest research results of functional inks for manufacturing flexible sensors using electrohydrodynamic inkjet printing (E-jet) technology. Firstly, the functional inks are categorized into metal nanomaterial inks, carbon material series inks, and organic polymer inks, as well as ceramic nanoparticle inks and metal oxide inks, and the processing of these functional inks in the fabrication of flexible sensors is discussed in detail, while the advantages and limitations of different types of functional inks are compared. Finally, the challenges facing the printing and manufacturing of flexible sensors by E-jet technology are discussed, and the future development prospects are envisioned to promote the further development and application of flexible sensors manufactured by E-jet technology. [ABSTRACT FROM AUTHOR]

Deposition of a passivation layer on top of the perovskite is proven to be an effective method for improving the efficiency and long‐term stability of perovskite solar cells (PSCs). And the spin‐coating method is the most typical and popular method developed for this purpose. However, the spin‐coating method wastes substantial passivator materials, thus the quantitative relationship between the passivator amount and the device performance cannot be obtained. Herein, a quantitative deposition method is developed through drop‐on‐demand inkjet printing to investigate the influence of 2‐adamantylamine hydrochloride (2‐ADAHCl) deposition surface density on the device performance, which is found to have a significant impact on the device performance. A low deposition surface density of 1.1 µg cm−2 does not reach its optimum passivation capability. In contrast, an excess deposition surface density of 10.1 µg cm−2 would lead to energy level mismatch and large series resistance at the perovskite/hole transport layer (HTL) interface, thus resulting in inferior device properties. At an optimum deposition surface density of 2.5 µg cm−2, perovskite surface defects are greatly suppressed, and the interfacial contact between perovskite and HTL is improved. Finally, PSCs with a high efficiency of 24.57% are achieved with improved operational and environmental stabilities. [ABSTRACT FROM AUTHOR]

The direct ink writing (DIW) technique is considered efficient for manufacturing complex-shaped Cf/SiC composites. However, the SiC slurry with high load has poor flow ability and covering-fibers properties, resulting in numerous gaps between the ceramic matrix and fibers. This study utilized DIW to manufacture Cf/SiC composites and improved the slurry's printing ability by adjusting the binder content. Moreover, the printing parameters, such as the angle between the fiber nozzle and slurry nozzle and the slurry nozzle size, were optimized to enhance the accuracy of the body structure and the filling effect of the slurry on the fiber gaps. The results showed that a binder content of 0.4 wt% produced excellent thixotropic, viscoelastic, and shear thinning behavior in the slurry. By using a fiber nozzle angle of 60° and a nozzle diameter of 1.55 mm, the slurry effectively filled the gaps between the fiber bundle and matrix, reducing the number and size of pores in the SiC matrix. These improvements greatly enhance the density, strength, and fracture toughness of the Cf/SiC composites. Therefore, this research demonstrated that optimizing the printing parameters not only improved the structural accuracy of the printed bodies but also greatly enhanced the properties of the ceramic matrix composites. [ABSTRACT FROM AUTHOR]

Wearable thermoelectric devices are widely used due to their ability to generate heat and cool rapidly without the need for bulky external equipment. Researchers have explored methods to enhance flexibility and stretchability by incorporating liquid metal as an electrode. However, the challenge lies in the low thermal conductivity of the polymer, which hampers heating and cooling performance. Traditional methods, like molding and spraying, increase the thickness of both liquid metal and polymer channels, but this added thickness does not significantly improve the device's stretchability.[1, 2] To overcome these issues, this paper proposes a stretchable thermoelectric device (STED), which offers improved heating and cooling capabilities, as well as enhanced stretchability. To enhance the thermal conductivity of the polymer, Ag powder with varying particle sizes is mixed with the material. Additionally, the liquid metal is deposited using the direct ink writing (DIW) method, reducing the whole thickness of STED. The air layer is created by printing molten isomalt, which is subsequently removed using water. The proposed STED exhibits high stretchability, reaching up to 150 %, enabling flexible twisting in various directions. The double‐layer structure resulted in a maximum temperature decrease of 14 °C at room temperature. [ABSTRACT FROM AUTHOR]

In historical recto–verso manuscripts, very often the text written on the opposite page of the folio penetrates through the fiber of the paper, so that the texts on the two sides appear mixed. This is a very impairing damage that cannot be physically removed, and hinders both the work of philologists and palaeographers and the automatic analysis of linguistic contents. A procedure based on neural networks (NN) is proposed here to clean up the complex background of the manuscripts from this interference. We adopt a very simple shallow NN whose learning phase employs a training set generated from the data itself using a theoretical blending model that takes into account ink diffusion and saturation. By virtue of the parametric nature of the model, various levels of damage can be simulated in the training set, favoring a generalization capability of the NN. More explicitly, the network can be trained without the need for a large class of other similar manuscripts, but is still able, at least to some extent, to classify manuscripts with varying degrees of corruption. We compare the performance of this NN and other methods both qualitatively and quantitatively on a reference dataset and heavily damaged historical manuscripts. [ABSTRACT FROM AUTHOR]

Direct ink writing of 3D WC-Co with conformable green bodies was achieved benefiting from the highly flexible WC-Co paste with high solid loading. Rheology properties of the paste, microstructure of the 3D structure was investigated. Organic-based paste of WC-8Co with a high solid content of 91 wt% were prepared, which exhibited shear thinning behavior and had a high storage modulus, two key parameters for ensuring the smooth printing. After secondary molding, 3D WC-Co green bodies with overhanging structure and no cracks were confirmed through secondary treatment of twisting or bending. Sound 3D structures with uniform and dense microstructure were obtained after debinding and sintering in vacuum. This work showed a facile route for the fabrication of 3D bone cemented carbides by direct ink writing with flexible green bodies. [ABSTRACT FROM AUTHOR]

To achieve consistent color reproduction of printed products and accurate measurement the content of mixed ink has always been an important research topic in the printing industry. This paper proposes a spectral-based method for measuring the content of dual-color mixed printing ink, aiming to solve the difficulty in determining the specific content of the base color in the same ratio of dual-color ink by using spectral analysis. First, a composite filtering method combining median filtering and wavelet transform was compared and selected for spectral preprocessing. Then, three methods, namely the successive projections algorithm (SPA), competitive adaptive reweighted sampling method (CARS), and stable competitive adaptive weighted sampling method (SCARS), were used to extract feature wavelengths from the preprocessed information. Based on partial least squares regression (PLSR), four models, PLSR, SPA–PLSR, CARS–PLSR, and SCARS, were established for predictive analysis. To further test the model, the SCARS–PLSR model was used for predictive analysis of magenta-cyan, yellow-magenta, and yellowcyan binary samples with a mass fraction ratio of 0.5. The results showed that the SCARS–PLSR model has the best predictive performance, with RMSE and R2 values of 0.0052, 0.0002, 0.0004 and 0.9989, 0.9999, 0.9999, respectively. This indicates that this study can accurately determine the content of dual-color ink by spectral analysis. [ABSTRACT FROM AUTHOR]

Through the dual keywords--wenfang 文房 and "four friends" (siyou 四友)--this essay examines the inextricable interrelationship among material things, a place, and the self that was initiated during the Song dynasty (960-1279). Song literati displayed unprecedented interest in scholarly things, particularly four specific things in the studio--the writing brush, inkstone, paper, and ink. Through literary representations, this article investigates the changing nature of the literati's relation to these "four things" in the studio. Rather than framing their bond as the ruler and ministers or the owner and his possessions, from the early Northern Song to the Southern Song, writers transformed their relationship to these four things gradually to that between friends and peers, or from pure ownership to an imaginary friendship, and in turn, these four things supported the construction of both the personal studio and the collective identity of the new elites in the Song. This transformation from "four things" or "four treasures" to "four friends" represented a distinctive model of the observation and conception of material things that Song scholars developed, which provided intriguing insights into the relationship between humans and things in premodern China. [ABSTRACT FROM AUTHOR]

The utilization of 3D printing technology for the fabrication of intricate transparent ceramics overcomes the limitations associated with conventional molding processes, thereby presenting a highly promising solution. In this study, we employed direct ink writing (DIW) to prepare yttrium oxide transparent ceramics using a ceramic slurry with excellent moldability, solid content of 45 vol%, and shear-thinning behavior. A successfully printed transparent yttrium oxide ring measuring 30 mm in diameter, 10 mm in inner diameter, and 0.9 mm in thickness was obtained from the aforementioned slurry. After de-binding and sintering procedures, the printed ceramic exhibited in-line transmittance of 71% at 850 nm. This work not only produced complex yttria transparent ceramics with intricate shapes, but also achieved in-line transmittance that was comparable to that of the CIP method (79%), which can meet certain optical applications. [ABSTRACT FROM AUTHOR]

Manufacturing intricately controlled, hierarchically distributed structures poses significant fabrication challenges, but is crucial for enhancing functionality in synthetic systems. A 3D printing technique combining advective assembly with rotational direct ink writing is developed and exploited to build topologically complex, multimaterial structures with high precision. A modular advective assembler printhead is fabricated and employed in the process. This flow‐structuring device is designed with a complex network of internal channels that patterns flowing hydrogel‐based inks, creating multi‐layered filaments whose structures go well beyond conventional nozzle shape and size limitations. The composite filaments are extruded into a rotating support bath of Polyacrylic acid microgels. The rheology of the inks and support bath are critical to maintain print fidelity and integrity, and are characterized by linear and nonlinear bulk rheometry. Optimization of the materials creates a platform where curvilinear, multimaterial architectures are constructed without being constrained to slicing across X, Y, and Z axes. The versatility of this manufacturing platform is demonstrated by printing helical structures that undergo swelling‐induced actuation. This processing method has the potential to significantly enhance additive manufacturing by enabling the production of intricate, multiscale composite structures with broad applicability in fields such as bioengineering, soft robotics, and functional composite materials. [ABSTRACT FROM AUTHOR]

Sb2Te3-based thermoelectric (TE) ink was synthesized by mixing different Sb2Te3 microsizes with a ChaM-based solution. A thick-film TE was fabricated via a screen-printing technique on SiO2/Si-wafer substrates. The thickness of the film was controlled at 200 µm, the film was dried on hotplates at 433 K for 30 min, and the film was annealed at 523 K under vacuum for 30 min. The crystal structure, morphology, chemical composition, Seebeck coefficient, electrical resistivity, thermal conductivity, and ZT were evaluated for the annealed film samples. The small powder size of Sb2Te3 was found to be in good condition, and a maximum ZT value of 1.04 was obtained at 468 K, which is more than three times that of the large size at the same temperature. [ABSTRACT FROM AUTHOR]

Infrared (IR) optoelectronics have become important owing to their various applications, such as recognition, autonomous driving, and quantum communications. In particular, detection beyond 1400‐nm wavelength in the shortwave IR (SWIR) spectrum (i.e., 1550 nm) is important for eye safety, and long‐range communication. Recently, group III–V (InAs or InSb) colloidal quantum dots (CQDs) have attracted considerable interest due to their broadband optical tunability and toxic‐elements (Pb and Hg)‐free properties. Herein, a new approach is developed to synthesize highly monodispersed InSb CQD by employing the continuous injection method, which enables facile optical bandgap tuning at a SWIR wavelength of up to 0.9 eV. Furthermore, solution ligand exchange using halides and thiolates results in effective passivation of the InSb CQD surface and renders a stable p‐type CQD ink. Finally, bulk heterojunction (BHJ) structure is demonstrated using n‐type InAs:p‐type InSb CQDs, which exhibits broad absorption up to 1600 nm, and a sixfold higher responsivity compared with the pristine InSb CQD device due to the efficient charge transport in BHJ CQD solids. [ABSTRACT FROM AUTHOR]

Raman spectral references for various formulations of iron gall inks, logwood inks and mixtures of both types were acquired during this study. The samples, either liquid or dry inks and applied on paper, were analysed using a portable Raman spectrometer, both with 852 and 785 nm excitation lines, and a confocal dispersive Raman microscope with two different excitations, namely 785 and 532 nm. It was found that longer wavelengths are more suitable for the analysis of iron gall inks and that the spectral response of logwood inks is relatively more dependent on the excitation line. For the mixtures, it is suggested analyses be performed with both longer and shorter wavelengths, since with a 785 nm line mainly the characteristic features of the metal-polyphenol complex in iron gall inks are detected, while the spectra collected with a 532 nm excitation contain information on the presence of logwood inks. The study was complemented by non-invasive reflectance infrared spectroscopy, which enabled the detection of tannic acid in iron gall inks and in the mixtures, and by micro-Fourier transform infrared (FTIR) spectroscopy to complement the reference set. The study aims to contribute to the development of non-invasive protocols for identification of inks in historic and artistic works on paper, such as manuscripts and drawings. [ABSTRACT FROM AUTHOR]

In the present research work is demonstrated a cross-scale manufacturing approach for the production of multifunctional glass fiber reinforced polymer (GFRP) composite tubes with a purposely redesigned filament winding process. Up until now, limited studies have been reported towards the multiscale reinforcement direction of continuous fibers for the manufacturing of hierarchical composites at the industrial level. This study involved the development of two different multi-walled carbon nanotube (MWCNT) aqueous-based inks, which were employed for the modification of commercial glass fiber (GF) reinforcing tows via a bath coating unit in a pilot production line. The obtained multifunctional GFRP tubes presented a variety of characteristics in relation to their final mechanical, hydrothermal aging, electrical, thermal and thermoelectric properties. Results revealed that the two individual systems exhibited pronounced differences both in crushing behavior and durability performance. Interestingly, for lateral compression the MWCNT coatings comprising a polymeric dispersant minorly affected the mechanical response of the produced tubes. The crashworthiness indicators of the multifunctional tubes displayed a slight 5% variation to the respective reference values, combined with a more ductile behavior. Moreover, regarding the bulk electrical and thermal conductivity values, as well as the Seebeck coefficient factor, the corresponding tubes displayed a variance of 233% and 19% and an opposite semi-conducting sign denoting a p- and n-type character, respectively. [ABSTRACT FROM AUTHOR]

Silver-based metal–organic decomposition inks composed of silver salts, complexing agents and volatile solvents are now the subject of much research due to the simplicity and variability of their preparation, their high stability and their relatively low sintering temperature. The use of this type of ink in inkjet printing allows for improved cost-effective and environmentally friendly technology for the production of electrical devices, including flexible electronics. An approach to producing a silver salt-based reactive ink for jet printing has been developed. The test images were printed with an inkjet printer onto polyimide substrates, and two-stage thermal sintering was carried out at temperatures of 60 °C and 100–180 °C. The structure and electrical properties of the obtained conductive lines were investigated. As a result, under optimal conditions an electrically conductive film with low surface resistance of approximately 3 Ω/square can be formed. [ABSTRACT FROM AUTHOR]

Inkjet is a versatile non‐contact printing technique that uses droplets of ink jetted from nozzles to print on a variety of substrates. Although some modern piezoelectric printheads support high viscosity fluids (>10 cP), they are currently expensive and may not be suited for many benchtop experiments in research environment. Here, the design, fabrication by 3D‐printing (no cleanroom processes or silicon micromachining are involved) and testing of a multi‐purpose single‐nozzle piezoelectric dispenser/printhead for medium‐viscosity fluids (10–60 cP) is reported. Custom control electronics are developed to drive the printhead. The design features a 200 μm diameter nozzle, suitable for nL drop generation with solutions containing nm sized particles, thus allowing the deposition of μm thick layers of functional inks in a single printing pass. The inkjet dispenser is first tested with glycerol solutions, resulting in drops of 1.9–3.6 nL with typical drop velocity of 0.5–1.3 m s−1. The developed piezoelectric dispensing system is then demonstrated in the printing of a two‐layer capacitive sensor, using silver nanoparticle ink (conductive ink) and a transparent encapsulant ink (dielectric ink). The reported piezoelectric dispenser design can be optimized for many research purposes, allowing the dispensing of functional chemicals, materials, and biomolecules. [ABSTRACT FROM AUTHOR]

The article "Learning Through Practice: On How Kemyt Contributed to Crafting and Transmitting Scribal Knowledge" by Aurore Motte examines the practices of ancient Egyptian scribes and how they transmitted their knowledge. It analyzes the structure of the Kemyt text and the choice of ink and writing direction used. It is determined that there was a complex network of scribes who contributed to the development and transmission of written knowledge. The Kemyt text has been found in various materials and regions of Egypt and describes different features of the Kemyt specimens found in Deir el-Medina. Various types of corrections and revisions in Egyptian literary texts are also described. The texts demonstrate the changes in literary culture during the New Kingdom. Various aspects of Egyptian script and language are also addressed. [Extracted from the article]

Additive manufacturing (AM) has significant utility for off-planet fabrication where dedicated infrastructure is severely limited, weight reduction and in situ resource utilization is desirable, and demands for complex systems are high. Direct ink writing (DIW) is a useful AM technique since it enables the deposition of a broad set of materials and the co-printing of multiple materials simultaneously. This allows for the fabrication of complex functional devices and systems in addition to structural objects. To evaluate this technique for space applications, this study characterized DIW in low gravity environments. Parabolic flights were used to simulate Martian, Lunar, and Micro gravity, and the effects that these 3 gravity regimes have on two critical print performance parameters, drooping and slumping, was evaluated using viscous paste inks deposited with an auger-driven extrusion head. In the drooping case, bridging structures were printed across gaps without support material, and the deformation was monitored. In the slumping case, a wall was printed through sequential layer deposition, and the vertical displacement of each layer under reduced gravity was explored. As expected, we found that a reduction in apparent gravity led to a decrease in the droop of a printed line, and as apparent gravitational acceleration is decreased its impact on the magnitude of drooping becomes less significant. For wall structures printed in simulated Lunar or Martian gravity regimes, the total structure height was found to be similar to that of a structure printed under Earth's gravitational conditions. In contrast, for prints performed in microgravity, it was found that slumping was significantly reduced and structure height was larger. These results provide experimental data to enable the design and optimization of appropriate structures and tool paths for printing objects using DIW for off-planet manufacturing. • Parabolic flights were used to evaluate direct ink write 3D printing under Lunar, Martian, and micro gravity regimes. • Structures made under these conditions show lower rates and degrees of deformation, allowing extended unsupported features. • A significant reduction in the slumping of multilayer prints occurs under microgravity conditions. [ABSTRACT FROM AUTHOR]

Inkjet 3D printing has potential in the additive manufacturing of electronic circuits and devices. However, inks that can be used for printing layers with T5%>300 °C or hardness>200 MPa have been rarely reported. Cyanate ester (CE) polymers have excellent thermal stability, high strength, and low shrinkage compared to other common dielectric inks for inkjet 3D printing, but cannot be quickly shaped by ultraviolet (UV) irradiation or thermal treatment. Combining CEs with UV-curable monomers may be a possible way to accelerate crosslinking, but there are challenges from the adverse effects of the dilution of both monomers. In this study, dielectric inks with acrylate and cyanate moieties were developed. The low viscosity and surface tension of the CE precursor (Bisphenol E cyanate ester) were combined with photocurable acrylate diluent monomers and cross-linker to realize an ink suitable for inkjet 3D printing. An internal dual three-dimensional cross-linked network structure resin was prepared by a combination of photocuring and thermal curing with T5% up to 326.69 °C, hardness up to 431.84 MPa, dielectric constant of 2.70 at 8 GHz, and shrinkage of 1.64%. The developed dielectric inks can be applied to the 3D printing of printed circuit boards and other electronic devices that require dielectric properties. [ABSTRACT FROM AUTHOR]

Sitting might be associated in our minds with a break in action; less a gesture than a slump into inertia. However, by analyzing John Milton's Samson Agonistes (1671), John Webster's The Duchess of Malfi (1614), and texts on melancholy and Hercules's attack on the Pygmies, we argue that manifold ideas about madness and melancholy are encapsulated in the early modern sitting body. Hercules, Samson, and the Duchess are explicitly written—or can be read—as mad and melancholy. Like Lucas Cranach and Albrecht Dürer's depictions of Melancholia, these characters are seen in a sitting posture. By sitting decisively, the Duchess and Samson alert us to their early modern context which is rife with visual and textual depictions of sitting. Thereby, they invite us to read their sitting bodies as sites where madness and rationality, power and dependency, and different genders, incline into and towards each other. [ABSTRACT FROM AUTHOR]

The direct ink writing (DIW) technique utilizing a single-screw mixing exhibits the capability of fabricating functionally graded materials (FGMs) featuring continuous gradients. Nevertheless, the vast array of parameters involved in the printing process and the absence of standard values and suitable matching relationships between individual parameters are factors that negatively impact print quality. This, in turn, hampers the potential application of FGMs across a multitude of fields. Thus, the primary objective of this study was to devise a process parameter model that can facilitate the setup of additional control parameters. To this end, the parametric model was constructed on the basis of the correlation between volumetric flow and pressure in each zone, and took into consideration all structural parameters of the prototype and material property parameters. Moreover, the digital image processing was employed to analyze and compare the printing results of FGM samples fabricated using different screw speeds across three groups. The analysis revealed that for stacking quality, deviations from the optimal screw speed resulted in understacking or overstacking. Furthermore, unsuitable screw speeds led to inconsistencies between the printed material information and the expected results. [ABSTRACT FROM AUTHOR]

This study reports the use of tin oxide (SnO 2) octahedral nanoparticles with exposed high-energy facets as sensing material in inkjet-printed carbon monoxide (CO) gas sensors. The nanoparticles were synthesized via a hydrothermal method aimed at encouraging high-indexed (221) crystal planes to be exposed as facets, since their high surface energy may encourage interactions with gases. Studies by X-ray diffraction (XRD) confirmed the identity of the SnO 2 , while transmission electron microscopy (TEM) revealed formations of octahedral-shaped SnO 2 nanoparticles, with features confirming the exposure of high-energy (221) crystal facets. The nanoparticles' reductive behavior in a CO environment was studied using temperature-programmed reduction (TPR). A stable ink based on the SnO 2 nanoparticles was successfully prepared and utilized to fabricate, via inkjet printing, homogenous films onto electrically conductive graphene-based interdigitated electrodes. Optimizing the inkjet printing parameters enhanced the CO gas sensing performance of the fabricated sensors. For example, at 200 ppm, the sensor with 10 printed layers recorded a sensitivity of about 20%, as compared to a sensitivity of not more than 14% recorded in each of the sensors with 5, 15, and 20 printed layers. As a result of having homogenous films, the inkjet-printed sensors also exhibited almost double the sensitivity of similar sensors prepared by drop-casting method. [Display omitted] [ABSTRACT FROM AUTHOR]

Functional inkjet printing is an emerging manufacturing technology for the production of various planar elements and electronic devices. This technology offers affordable freeform and highly customizable production of thin film micron-scale elements on various substrates. Functional inkjet printing employs various inks based on organic and inorganic materials with diverse functional properties, and among them, conjugated polymers are of particular interest due to their electrical, photophysical, and electrochemical properties. This paper provides an overview of inkjet printing with conjugated (semi)conductive polymers, including the fundamentals of the technology and its scope, limitations, and main challenges. Specific attention is drawn to the synthesis and chemistry of these polymers in connection with the patterning and functional properties of the inks composed thereof. Practical aspects of this technology are also highlighted, namely the manufacturing capabilities of the technology and particular applications for the fabrication of various electronic elements and devices. [ABSTRACT FROM AUTHOR]