Liquid Deposition Research Articles

Direct liquid injection pulsed-pressure MOCVD of large area MoS2 on Si/SiO2.

Large-scale, high-quality growth of transition metal dichalcogenides (TMD) of controlled thickness is paramount for many applications in opto- and microelectronics. This paper describes the direct growth of well-controlled large area molybdenum disulfide (MoS2) on Si/SiO2 substrates by direct liquid injection pulsed-pressure metal-organic chemical vapor deposition (DLI-PP-MOCVD) using low-toxicity precursors. It is shown that control of the deposited thickness can be achieved by carefully tuning the amount of molybdenum precursor evaporated and that continuous layers are routinely obtained. Homogeneity and reproducibility have also been examined, as well as the average size of the grains. When targeting monolayer thickness, the MoS2 showed near stoichiometry (S/Mo = 1.93-1.95), low roughness and high photoluminescence (PL) quantum yield, equivalent to exfoliated monolayers and CVD MoS2 grown on the same substrates.

Epitaxial LiNbO3 growth and layer transfer for thin-film electro-optic modulator realization

The aim of the PhD project is to develop a new trend in modulation system for Exail company: thin film (<1 μm) lithium niobate (LN) electro-optic modulator. It exhibits better performance in term of bandwidth, power consumption and footprint than legacy ones [1-3]. This PhD is a cooperation between Exail photonics which is world-renowned for the performances of their electro-optic modulators and FEMTO-ST institute which can offer the possibility to grow stoichiometric LN thin film by means of direct liquid injection metalorganic chemical vapor deposition (DLI-MOCVD). This cooperation opens the possibility to obtain industrialization of optical device based on CVD LN stoichiometric layers which allow to have enhanced performances such as higher electro-optic coefficient than that of congruent compositions of commercial single crystals. Thus, all steps from MOCVD layer deposition to modulator realization can be done here in Besançon.

MATHEMATICAL MODELS OF THE NODE OF TECHNOGENIC INFLUENCE, TAKING INTO ACCOUNT THE MAIN DIRECTIONS OF MATERIAL FLOWS IN THE LOGISTICS OF MINING ENTERPRISES

ABSTRACT. The aim of the work is to create a mathematical model of liquid waste storage that accumulates processed products and mine waters simultaneously from many mining and processing plants, taking into account technological constraints on waste volumes and climatic factors depending on the season. The proposed mathematical model of node of technogenic influence is based on the balance of material flows in and out the node. A typical node of technogenic influence is an accumulation node. In the problem considered in this paper, the accumulation node is a waste storage facility where liquid man-made deposits are stored. The model of this node includes a system of equations describing the height of the water mirror and the bottom level depending on the volume of placers and water in and out for the analysed period of operation, taking into account the geometric features of the storage. The main directions of material flows can be formed from two or three nodes of technogenic influence. The first case is typical for underground mining, and the second one is typical for open pit mining. In the second case, the main direction is formed from the node of extraction of primary deposits, the node of processing or separation, and the node of accumulation or the node of storage of man-made deposits. The mathematical model makes it possible to determine the level of the free surface mirror in any month of the year, as well as to calculate the change in the current height of the water mirror in storage for any period of the year, such as spring months or all year round.

Microstructure and high-temperature oxidation behavior of Al2O3/Cr composite coating on Inconel 718 alloy

In this paper, Al2O3/Cr composite coatings were prepared on the surface of Inconel 718 alloy by cathodic liquid plasma electrolytic deposition (CLPED) and double-glow plasma surface alloying (DGPSA) processes. The microstructure and high-temperature oxidation behavior of Al2O3/Cr composite coating were investigated. The results showed that the Al2O3 interlayer surface was fully covered with Cr coating. The interface between the Al2O3 layer and the Cr metal layer presents a mechanical interlock effect, which can absorb the deformation caused by thermal expansion, thereby reducing the adverse effects of thermal stress. The surface roughness of the Al2O3 coatings decreased after depositing Cr coating. The oxidation weight gain of the Al2O3/Cr composite coatings were significantly lower than that of the substrate, indicating that the Al2O3/Cr composite coatings improved the high-temperature oxidation resistance of Inconel 718 alloy. The oxidation weight gain of the Al2O3/Cr composite coatings at different frequencies were similar, while the Al2O3/Cr composite coating at 400 Hz was lowest. During the high-temperature oxidation process, the Al2O3 interlayer can effectively inhibit the external diffusion of Ni, Fe and other elements in the matrix, which helps to prevent the cracking of the outer oxide film, thereby reducing the oxidation rate.

Enhanced solar water splitting using bismuth ferrite photoanodes grown by direct liquid injection chemical vapor deposition

Enhanced solar water splitting using bismuth ferrite photoanodes grown by direct liquid injection chemical vapor deposition

Excellent field emission with enhanced photodetection behavior of multiwalled carbon nanotubes: experimental and theoretical study

In this study, we synthesized multiwalled carbon nanotubes (MWCNTs) using the direct liquid injection chemical vapor deposition (DLICVD) method, the growth temperatures were varied to investigate their unique properties.

Exploring the Potential of Residual Aspergillus Mycelium as a Sustainable Material for Additive Biomanufacturing

Non-degradable materials are responsible for a variety of negative socio-environmental effects. In order to realize a sustainable bioeconomy a circular design of production systems based on biogenic resources is inevitable. Consequently, the recycling of residual and side-streams is becoming increasingly relevant. In this paper, we investigate the potential of using sterilized mycelium from Aspergillus niger, which occurs as a residual-product from the citric acid production, as a sustainable material for additive biomanufacturing by using the Liquid Deposition Modeling technology. The mycelium-based material is extruded through a specially designed printer head, enabling a multi-layered fabrication of complex structures. In combination with additives such as fibers the mycelium can lead to materials with promising mechanical characteristics and shows good properties for its use as an innovative material to be applied in additive manufacturing processes. We conclude that additive biomanufacturing with mycelium from Aspergillus is a sustainable alternative for traditional materials. Its biodegradability characteristic makes it a promising material for various applications and circular products. Finally, we outline further research and development issues to enable the transformation into industrial applications.

Fabrication of PEEK Ag/AgI mid-infrared hollow fiber and transmission reliability study for CO2 laser radiation

Hollow fiber is a crucial means for delivery of mid-infrared laser radiation and has a wide range of applications in laser surgery and other fields. At present, there is still a lack of low-cost, highly flexible plastic hollow fiber that can reliably transmit mid-infrared laser with low loss. In this study, flexible Poly ether ether ketone (PEEK) tubing material was selected as the structural tube for establishing a robust plastic Ag/AgI mid-infrared hollow fiber. Fiber samples with inner diameters of 1.0, 1.5 and 2.0 mm were prepared using plasma treatment and dynamic chemical liquid deposition processes. The transmission losses for CO2 laser of the 1.0-, 1.5- and 2.0-mm-bore PEEK Ag/AgI hollow fibers increased from 0.40, 0.18 and 0.10 dB/m to 2.35, 1.60 and 1.05 dB/m, respectively, as they were bent at an angle from 0° to 180° with a radius of 15 cm. The hollow fibers could stably transmit CO2 laser in high (120 °C) and low (-78.5 °C) temperature environments. After undergoing 100 h of accelerated humidity-heat aging (85 °C, 85 % RH) and 10 cycles of high-low (-40 ∼ 85 °C) temperature cycling treatment, the transmission loss remained almost unchanged. The PEEK Ag/AgI hollow fiber exhibited high energy damage threshold and it could stably deliver a 10 ∼ 20 W CO2 laser beam for 20 min to 5 h when bent at a 25 cm radius and a 90° angle. The current research provides a possible approach for developing low-cost, highly flexible, low-loss and highly reliable mid-infrared hollow fibers. It is helpful to promote the applications of CO2 laser in laser medicine, intelligent manufacturing and sensing.

Home, unsweet home – effect of homeownership on financial investments of Indian households

PurposeThe study analyzes the relationship between homeownership and financial investment of households in the context of emerging markets like India. It also examines how homeownership affects the portfolio decisions of Indian households.Design/methodology/approachUsing the nationally representative All-India Debt and Investment Survey of 2019 and employing an instrumental variable approach, the authors analyze the relationship between homeownership and the share of financial assets held by Indian households. The study also employs several sensitivity checks, including alternate estimation techniques and alternative definitions of the housing variables, and accounts for additional factors to ensure that the authors are able to capture the effect of homeownership on the outcome variable.FindingsThe analysis suggests homeownership crowds out financial investment in India due to high repair and maintenance costs. The negative effect is mainly observed in urban households. Further, the findings imply that homeownership leads households to reallocate their asset portfolio. Homeowners have a lower share in liquid short term deposits, indicating the high liquidity risk of their portfolios. On the other hand, homeownership increases the share of long term retirement funds along with no effect on risky asset share. The authors observe that the crowding out effect is more striking for younger households and poorer households with low income, and the effect is lower for indebted households.Practical implicationsThe findings underscore the need for financial awareness programs so that housing does not crowd out liquid investments of households. Additionally, the results highlight that policies should first focus on young and poor households as the negative effect is more prominent for these groups. Finally, there is scope for policies to support repair and maintenance costs incurred by vulnerable households to reduce the negative effect of housing on liquid financial investments.Originality/valueThis paper is among the few studies that provide insights into how homeownership relates to financial investment and portfolio decisions in the context of an emerging economy. Furthermore, the heterogeneous effects based on poor economic status and age underscore the need for complementary policies.

AP assembled on ultrafine aluminum particle and its application to NEPE propellant

Coating modification is an important way to enhance the reactivity of aluminum powder. In this paper, ammonium perchlorate and aluminum powder were assembled into energetic microunits by liquid deposition method. Spherical particles with AP as shell and ultrafine aluminum powder as the core (Al@AP) were gained. The micromorphology results show that the coated particles are about 5 μm, and the coating layer is evenly distributed on the outer surface of aluminum powder, indicating a complete coating. The energetic microunits were implanted into the nitrate ester plasticizing adhesive system (NEPE) as solid phase fillers. The effect of filler on the rheological properties, safety, mechanical properties, thermal reaction and energy properties of the system was analyzed by comparing with the raw aluminum filler. The test results show that the rheological properties, mechanical properties and pressure index of NEPE containing system Al@AP meets the requirements of solid propellant charging. Compared with Al based propellant, the mechanical sensitivity and thermal sensitivity are decreased, the safety is better, and the explosion heat of the propellant is increased by 7.8%. The engine test shows that the specific impulse is increased by 1.2 s. Al@AP can improve the energy output and safety of NEPE propellant, and has potential application prospects in high-energy propellants.

Preparation of and Self-Catalytic Performance AP/CuCo2O4 Core–Shell Energetic Composites

To reduce the thermal decomposition temperature of ammonium perchlorate, Copper cobaltate (CuCo2O4) was prepared and precipitate on the surface of AP by liquid deposition method. The performance of specimen were characterized by X-ray diffraction, transmission electron microscope and fourier transform infrared spectroscop. The self-catalysis of AP/CuCo2O4 core—shell energetic composites was evaluated by differential thermal analysis. The analysis results show that CuCo2O4 was successfully coated on AP surface with good coating effect. And DTA results show that AP/CuCo2O4 core—shell energetic composites have good self-catalysis. When the content of CuCo2O4 in core—shell energetic composites is 6%, it shows the best self-catalytic property, the pyrolysis peak of AP decreased by 194.79 °C, and the heat release of high temperature decomposition peak increased by 773.89 J • g–1. The investigations indicate that AP/CuCo2O4 core—shell energetic composites have shown better catalytic effect than CuCo2O4, and provides a new ideal in the field of soild propellant catalysis.

Hydrophobicity of molecular-scale textured surfaces: The case of zeolitic imidazolate frameworks, an atomistic perspective.

Hydrophobicity has proven fundamental in an inexhaustible amount of everyday applications. Material hydrophobicity is determined by chemical composition and geometrical characteristics of its macroscopic surface. Surface roughness or texturing enhances intrinsic hydrophilic or hydrophobic characteristics of a material. Here we consider crystalline surfaces presenting molecular-scale texturing typical of crystalline porous materials, e.g., metal-organic frameworks. In particular, we investigate one such material with remarkable hydrophobic qualities, ZIF-8. We show that ZIF-8 hydrophobicity is driven not only by its chemical composition but also its sub-nanoscale surface corrugations, a physical enhancement rare amongst hydrophobes. Studying ZIF-8's hydrophobic properties is challenging as experimentally it is difficult to distinguish between the materials' and the macroscopic corrugations' contributions to the hydrophobicity. The computational contact angle determination is also difficult as the standard "geometric" technique of liquid nanodroplet deposition is prone to many artifacts. Here, we characterise ZIF-8 hydrophobicity via: (i) the "geometric" approach and (ii) the "energetic" method, utilising the Young-Dupré formula and computationally determining the liquid-solid adhesion energy. Both approaches reveal nanoscale Wenzel-like bathing of the corrugated surface. Moreover, we illustrate the importance of surface linker termination in ZIF-8 hydrophobicity, which reduces when varied from sp3 N to sp2 N termination. We also consider halogenated analogues of the methyl-imidazole linker, which promote the transition from nanoWenzel-like to nanoCassie-Baxter-like states, further enhancing surface hydrophobicity. Present results reveal the complex interface physics and chemistry between water and complex porous, molecular crystalline surfaces, providing a hint to tune their hydrophobicity.

Fluid Dynamics of Airtanker Firefighting

Airtanker firefighting is the most spectacular tool used to fight wildland fires. However, it employs a rudimentary large-scale spraying technology operating at a high speed and a long distance from the target. This review gives an overview of the fluid dynamics processes that govern this practice, which are characterized by rich and varied physical phenomena. The liquid column penetration in the air, its large-scale fragmentation, and an intense surface atomization give shape to the rainfall produced by the airtanker and the deposition of the final product on the ground. The cloud dynamics is controlled by droplet breakup, evaporation, and wind dispersion. The process of liquid deposition onto the forest canopy is full of open questions of great interest for rainfall retention in vegetation. Of major importance, but still requiring investigation, is the role of the complex non-Newtonian viscoelastic and shear-thinning behavior of the retardant dropped to stop the fire propagation. The review describes the need for future research devoted to the subject.

In situ one-step production of hierarchical silicon nanofilaments/polyimide nonwovens for environmentally sustainable applications

Highly architectures with roughness and low surface energy reagent are the key toward developing superwetting materials. Silicon nanofilaments (SiNFs) had been grown on polyimide (PI) nonwovens by liquid deposition, which could enhance the hydrophobicity of the nonwovens without additives. These newly prepared nonwovens with micro/nano-scale secondary rough structures demonstrate outstanding air filtration and oil/water separation abilities. The in situ hybrid nonwoven shows extremely high efficiency air filtration function (the increase in filtration efficiency for PM1.0 by 63 % with stable pressure drop), stable particulate filtering effect after storage 15 months at ambient temperature, and good thermal stability at 350 °C. The oil/water separation test showed a separation efficiency of over 98 % and a high flux (above 40,000 Lm-2h−1) for different oil/water mixtures. Additionally, nonwovens prepared in this study demonstrated exceptional durability and stability when subjected to corrosive conditions, as evidenced by the results of realistic industrial simulations. The introduction of SiNFs on nonwoven, which combines the multiple capture and wettability properties, shows promise as a potential solution for large-scale air filtration and oil/water separation.

Dynamic Extrusion Control in Spot Deposition Modeling for Porous 3D Clay Structures

The dynamic state of the viscous clay in Liquid Deposition Modeling (LDM) often leads to discrepancies between the digital model and the resulting physical object. This emergent behavior can be harnessed to produce complex physical structures that would not be possible with other methods. This study takes advantage of the viscous state and tensile strength of the extruded clay strand to explore the impact of dynamic extrusion and deformations through travel paths in LDM to manufacture complex porous physical structures. The effects of these parameters are discussed in two case studies: (1) regular and semi-random Spot Deposition surfaces with either open or thickened regions, and (2) porous 3D lattice structures created through the controlled bending of vertical extrusions. The achieved higher geometrical complexity of objects through the algorithmically programmed alternations in the sequence and rate of material deposition allows for a wide range of buildup approaches that expand the production spectrum of sustainable small- and large-scale elements.

3D printing of a wood-based furniture element with liquid deposition modeling

Liquid deposition modeling is an energy-efficient, additive manufacturing process for pasty materials. Physical material properties were determined for a water-based paste consisting of the binder carboxymethyl cellulose and wood flour. A continuously operating dual screw extruder was developed, which was used to manufacture a table frame with a height of 18 cm.

Predicting the Splash of a Drop Impacting a Thin Liquid Film.

An experimental study is carried out to investigate droplet-film interactions when a drop impinges on a thin stagnant film of the same liquid. The impacting drop causes either liquid deposition or splash, consisting of prompt generation of secondary drops or a delayed process. By varying the drop diameter and impact velocity, measurements are made to characterize the phenomena using five different liquids that are chosen to cover a wide range of liquid properties (viscosity and surface tension). The drop impact dynamics are captured with a high-speed digital camera with real-time, high-resolution image processing. The drop-splash threshold is found to scale with inertial and viscous forces, or Reynolds number (Re), as well as capillary forces, as described by the balance of gravitational and interfacial tension forces, or Bond number (Bo); fluid properties are described by their Morton number (Mo). A correlation, functionally expressed as Re = ϕ(Bo,Mo), is devised to determine the splash/no-splash (or deposition) boundary, and the predictions for the splash/no-splash outcomes agree well with the experimental outcomes as well as those readily available in the literature.

Geodynamic regime and prospects for oil and gas potential in the South Caspian Basin


 
 
 The article considers the geodynamic regime of the South Caspian depression, de- fines the directions of compressive stresses, the role of the latter in changing the thickness of sedimentary formation complexes, in the formation of local uplifts and their complication by faults and mud volcanism. The purpose of the study is to research the geodynamic regime and determine the oil and gas content of the South Caspian depression. The article reflects the features of studying the zone of pseudosub- duction in the South Caspian depression and the analysis of the obtained results of the prospects of oil and gas potential from the point of view of the influence of modern geodynamic processes. The study of the intensity of the formation of sedimentary facies complexes in the South Caspian depression and the features of the intensity of sedimentation allows us to distinguish 4 stages in different time intervals. According to the analysis of the available data, an inverse relationship has been established between the duration of each stage and the thickness of deposits accumulated during this period of time. In other words, the shorter the duration of the stage, the greater the thickness of the formed deposits. It was found out that this is the result of geodynamic processes occurring within the Southern Caspian Sea and in the adjacent areas, and due to the prevailing geodynamic conditions, the uncompensated deflection regime prevailing for the bottom of the South Caspian Basin had a direct impact on the process of oil and gas formation in its sedimentary cover. The depths of the boundary isotherms of catagenesis and the zone of oil and gas formation were determined in order to determine the state of each sedimentary-facies complex in the vertical zonality of oil and gas formation. It was found that in the western part of the South Caspian Basin, the lower boundary of the protocatagenesis zone is 3 km, the isotherm of the lower boundary of the oil window corresponding to 1500 C is located at a depth of 11-12 km, and the depth of the main gas formation zone corresponding to 2500 C is 18-19 km. The presented analysis of the features of oil and gas formation makes it possible to predict the formation of liquid hydrocarbon deposits at depths corresponding to the oil formation zone.
 
 

Liquid Metal Interface for Two-Precursor Autogenous Deposition of Metal Telluride-Tellurium Networks.

Liquid metal-electrolyte can offer electrochemically reducing interfaces for the self-deposition of low-dimensional nanomaterials. We show that implementing such interfaces from multiprecursors is a promising pathway for achieving nanostructured films with combinatory properties and functionalities. Here, we explored the liquid metal-driven interfacial growth of metal tellurides using eutectic gallium-indium (EGaIn) as the liquid metal and the cation pairs Ag+-HTeO2+ and Cu2+-HTeO2+ as the precursors. At the EGaIn-electrolyte interface, the precursors were reduced and self-deposited autogenously to form interconnected nanoparticle networks. The deposited materials consisted of metal telluride and tellurium with their relative abundance depending on the metal ion type (Ag+ and Cu2+) and the metal-to-tellurium ion ratios. When used as electrode modifiers, the synthesized materials increased the electroactive surface area of unmodified electrodes by over 10 times and demonstrated remarkable activity for model electrochemical reactions, including HexRu(III) responses and dopamine sensing. Our work reveals the promising potential of the liquid metal-templated deposition method for synthesizing complex material systems for electrochemical applications.

Tailoring crystallisation of anatase TiO2 ultra-thin films grown by atomic layer deposition using 2D oxides as growth template

TiO2 ultrathin films are required in many material research areas. The anatase phase was found to be more stable in case of atomic layer deposition growth, nevertheless a critical thickness of around 10 nm appears necessary to obtain crystallization on native silicon oxide on Si (001). This work focuses on direct liquid injection Atomic Layer Deposition (ALD) of TiO2 films with thicknesses about some nanometers, using titanium tetra-isopropoxide as precursor and H2O as oxidant. A particular care to the treatment of ellipsometric measurements is employed. Below the threshold value, films remain amorphous unless the growth starts onto a crystalized surface, a thick TiO2 layer in our case. Here we propose and show the efficiency of 2-dimensional (2D) [Ca2Nb3O10]− and [Ti0.865O2]0.54− nanosheets as seeds at the surface for the crystallization and epitaxy of ultra-thin films of TiO2 below the critical thickness. Furthermore, we show that the structure of the 2D nanosheets determines the growth orientation of the epitaxial anatase, namely (010) for [Ti0.865O2]0.54−, and (100) for [Ca2Nb3O10]−. These results, based on the tailoring of crystal anisotropy via adapted 2D seed nanosheets and low temperature ALD, opens the way for opto-electronics applications of titanium oxide layers of a few unit cells.